Cationic antimicrobial peptides inactivate Shiga toxin-encoding bacteriophages

Science.gov (United States)

Del Cogliano, Manuel E.; Hollmann, Axel; Martinez, Melina; Semorile, Liliana; Ghiringhelli, Pablo D.; Maffía, Paulo C.; Bentancor, Leticia V.

2017-12-01

Shiga toxin (Stx) is the principal virulence factor during Shiga toxin-producing Escherichia coli (STEC) infections. We have previously reported the inactivation of bacteriophage encoding Stx after treatment with chitosan, a linear polysaccharide polymer with cationic properties. Cationic antimicrobial peptides (cAMPs) are short linear aminoacidic sequences, with a positive net charge, which display bactericidal or bacteriostatic activity against a wide range of bacterial species. They are promising novel antibiotics since they have shown bactericidal effects against multiresistant bacteria. To evaluate whether cationic properties are responsible for bacteriophage inactivation, we tested seven cationic peptides with proven antimicrobial activity as anti-bacteriophage agents, and one random sequence cationic peptide with no antimicrobial activity as a control. We observed bacteriophage inactivation after incubation with five cAMPs, but no inactivating activity was observed with the random sequence cationic peptide or with the non alpha helical cAMP Omiganan. Finally, to confirm peptide-bacteriophage interaction, zeta potential was analyzed by following changes on bacteriophage surface charges after peptide incubation. According to our results we could propose that: 1) direct interaction of peptides with phage is a necessary step for bacteriophage inactivation, 2) cationic properties are necessary but not sufficient for bacteriophage inactivation, and 3) inactivation by cationic peptides could be sequence (or structure) specific. Overall our data suggest that these peptides could be considered a new family of molecules potentially useful to decrease bacteriophage replication and Stx expression.

Cationic Antimicrobial Peptides Inactivate Shiga Toxin-Encoding Bacteriophages

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Manuel E. Del Cogliano

2017-12-01

Full Text Available Shiga toxin (Stx is the principal virulence factor during Shiga toxin-producing Escherichia coli (STEC infections. We have previously reported the inactivation of bacteriophage encoding Stx after treatment with chitosan, a linear polysaccharide polymer with cationic properties. Cationic antimicrobial peptides (cAMPs are short linear aminoacidic sequences, with a positive net charge, which display bactericidal or bacteriostatic activity against a wide range of bacterial species. They are promising novel antibiotics since they have shown bactericidal effects against multiresistant bacteria. To evaluate whether cationic properties are responsible for bacteriophage inactivation, we tested seven cationic peptides with proven antimicrobial activity as anti-bacteriophage agents, and one random sequence cationic peptide with no antimicrobial activity as a control. We observed bacteriophage inactivation after incubation with five cAMPs, but no inactivating activity was observed with the random sequence cationic peptide or with the non-alpha helical cAMP Omiganan. Finally, to confirm peptide-bacteriophage interaction, zeta potential was analyzed by following changes on bacteriophage surface charges after peptide incubation. According to our results we could propose that: (1 direct interaction of peptides with phage is a necessary step for bacteriophage inactivation, (2 cationic properties are necessary but not sufficient for bacteriophage inactivation, and (3 inactivation by cationic peptides could be sequence (or structure specific. Overall our data suggest that these peptides could be considered a new family of molecules potentially useful to decrease bacteriophage replication and Stx expression.

[Kinetics of catalase inactivation induced by ultrasonic cavitation].

Science.gov (United States)

Potapovich, M V; Eremin, A N; Metelitsa, D I

2003-01-01

Kinetic patterns of sonication-induced inactivation of bovine liver catalase (CAT) were studied in buffer solutions (pH 4-11) within the temperature range from 36 to 55 degrees C. Solutions of CAT were exposed to low-frequency (20.8 kHz) ultrasound (specific power, 48-62 W/cm2). The kinetics of CAT inactivation was characterized by effective first-order rate constants (s-1) of total inactivation (kin), thermal inactivation (*kin), and ultrasonic inactivation (kin(us)). In all cases, the following inequality was valid: kin > *kin. The value of kin(us) increased with the ultrasound power (range, 48-62 W/cm2) and exhibited a strong dependence on pH of the medium. On increasing the initial concentration of CAT (0.4-4.0 nM), kin(us) decreased. The three rate constants were minimum within the range of pH 6.5-8; their values increased considerably at pH 9. At 36-55 degrees C, temperature dependence of kin(us) was characterized by an activation energy (Eact) of 19.7 kcal/mol, whereas the value of Eact for CAT thermoinactivation was equal to 44.2 kcal/mol. Bovine serum and human serum albumins (BSA and HSA, respectively) inhibited sonication-induced CAT inactivation; complete prevention was observed at concentrations above 2.5 micrograms/ml. Dimethyl formamide (DMFA), a scavenger of hydroxyl radicals (HO.), prevented sonication-induced CAT inactivation at 10% (kin and *kin increased with the content of DMFA at concentrations in excess of 3%). The results obtained indicate that free radicals generated in the field of ultrasonic cavitation play a decisive role in the inactivation of CAT, which takes place when its solutions are exposed to low-frequency ultrasound. However, the efficiency of CAT inactivation by the radicals is determined by (1) the degree of association between the enzyme molecules in the reaction medium and (2) the composition thereof.

Inactivation Data.xlsx

Data.gov (United States)

U.S. Environmental Protection Agency — The data set is a spreadsheet that contains results of inactivation experiments that were conducted to to determine the effectiveness of chlorine in inactivating B....

Inactivation of pathogenic bacteria in food matrices: high pressure processing, photodynamic inactivation and pressure-assisted photodynamic inactivation

Science.gov (United States)

Cunha, A.; Couceiro, J.; Bonifácio, D.; Martins, C.; Almeida, A.; Neves, M. G. P. M. S.; Faustino, M. A. F.; Saraiva, J. A.

2017-09-01

Traditional food processing methods frequently depend on the application of high temperature. However, heat may cause undesirable changes in food properties and often has a negative impact on nutritional value and organoleptic characteristics. Therefore, reducing the microbial load without compromising the desirable properties of food products is still a technological challenge. High-pressure processing (HPP) can be classified as a cold pasteurization technique, since it is a non-thermal food preservation method that uses hydrostatic pressure to inactivate spoilage microorganisms. At the same time, it increases shelf life and retains the original features of food. Photodynamic inactivation (PDI) is also regarded as promising approach for the decontamination of food matrices. In this case, the inactivation of bacterial cells is achieved by the cytotoxic effects of reactive oxygens species (ROS) produced from the combined interaction of a photosensitizer molecule, light and oxygen. This short review examines some recent developments on the application of HPP and PDI with food-grade photosensitizers for the inactivation of listeriae, taken as a food pathogen model. The results of a proof-of-concept trial of the use of high-pressure as a coadjutant to increase the efficiency of photodynamic inactivation of bacterial endospores is also addressed.

The assessment of efficacy of porcine reproductive respiratory syndrome virus inactivated vaccine based on the viral quantity and inactivation methods

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Lee Byeongchun

2011-06-01

Full Text Available Abstract Background There have been many efforts to develop efficient vaccines for the control of porcine reproductive and respiratory syndrome virus (PRRSV. Although inactivated PRRSV vaccines are preferred for their safety, they are weak at inducing humoral immune responses and controlling field PRRSV infection, especially when heterologous viruses are involved. Results In all groups, the sample to positive (S/P ratio of IDEXX ELISA and the virus neutralization (VN titer remained negative until challenge. While viremia did not reduce in the vaccinated groups, the IDEXX-ELISA-specific immunoglobulin G increased more rapidly and to significantly greater levels 7 days after the challenge in all the vaccinated groups compared to the non-vaccinated groups (p 6 PFU/mL PRRSV vaccine-inoculated and binary ethylenimine (BEI-inactivated groups 22 days after challenge (p Conclusions The inactivated vaccine failed to show the humoral immunity, but it showed different immune response after the challenge compared to mock group. Although the 106 PFU/mL-vaccinated and BEI-inactivated groups showed significantly greater VN titers 22 days after challenge, all the groups were already negative for viremia.

The probability to initiate X chromosome inactivation is determined by the X to autosomal ratio and X chromosome specific allelic properties.

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Kim Monkhorst

Full Text Available In female mammalian cells, random X chromosome inactivation (XCI equalizes the dosage of X-encoded gene products to that in male cells. XCI is a stochastic process, in which each X chromosome has a probability to be inactivated. To obtain more insight in the factors setting up this probability, we studied the role of the X to autosome (X ratio A ratio in initiation of XCI, and have used the experimental data in a computer simulation model to study the cellular population dynamics of XCI.To obtain more insight in the role of the XratioA ratio in initiation of XCI, we generated triploid mouse ES cells by fusion of haploid round spermatids with diploid female and male ES cells. These fusion experiments resulted in only XXY triploid ES cells. XYY and XXX ES lines were absent, suggesting cell death related either to insufficient X-chromosomal gene dosage (XYY or to inheritance of an epigenetically modified X chromosome (XXX. Analysis of active (Xa and inactive (Xi X chromosomes in the obtained triploid XXY lines indicated that the initiation frequency of XCI is low, resulting in a mixed population of XaXiY and XaXaY cells, in which the XaXiY cells have a small proliferative advantage. This result, and findings on XCI in diploid and tetraploid ES cell lines with different X ratio A ratios, provides evidence that the X ratio A ratio determines the probability for a given X chromosome to be inactivated. Furthermore, we found that the kinetics of the XCI process can be simulated using a probability for an X chromosome to be inactivated that is proportional to the X ratio A ratio. These simulation studies re-emphasize our hypothesis that the probability is a function of the concentration of an X-encoded activator of XCI, and of X chromosome specific allelic properties determining the threshold for this activator.The present findings reveal that the probability for an X chromosome to be inactivated is proportional to the X ratio A ratio. This finding

Sexually localized expression of pseudo-self compatibility (PSC) in Petunia X hybrida Hort : 2. Stylar inactivation.

Science.gov (United States)

Dana, M N; Ascher, P D

1986-01-01

A previously identified S-linked stylar-inactivation PSC factor (Flaschenriem and Ascher 1979b) was studied for its location relative to S. Plants exhibiting complete stylar-inactivation PSC were those with higher multigenic PSC background level than plants with only S-linked partial stylar-inactivation PSC. A pollen-mediated pseudo-self compatibility (PMPSC) adjustment factor was offered as a device to focus on stylar-inactivation PSC by removing some male origin, multigenic PSC. The stylar inactivation factor was not tightly linked to S but affected expression of only the allele to which it was linked. A three part interacting association of genetic material governing self incompatibility (SI) is proposed. The parts of S are the SI identity gene, S-specific PSC genes and, finally, PSC genes which are not S-specific in action. The complete association is termed the SI-complex.

The radiation inactivation of glutamate and isocitrate dehydrogenases

International Nuclear Information System (INIS)

El Failat, R.R.A.

1980-12-01

The reaction of free radicals produced by ionizing radiation with the enzymes glutamate dehydrogenase (GDH) and NADP + -specific isocitrate dehydrogenase (ICDH) have been studied by steady-state and pulse radiolysis techniques. In de-aerated GDH solutions, hydroxyl radicals have been found to be the most efficient of the primary radicals generated from water in causing inactivation. The effect of reaction with the enzyme of selective free radicals (SCN) 2 - , (Br) 2 - and (I) 2 - on its activity has also been studied. In neutral solutions, the order of inactivating effectiveness is (I) 2 - > (Br) 2 - > (SCN) 2 - . In the case of the thiocyanate radical anion (SCN) 2 - , the inactivation efficiency is found to depend on KSCN concentration. The radiation inactivation of GDH at both neutral and alkaline pH is accompanied by the loss of sulphydryl groups. Pulse radiolysis was also used to determine the rate constants and the transient absorption spectra following the reaction of the free radicals with GDH. 60 Co-γ-radiolysis and pulse radiolysis were also used to study the effect of ionizing radiation on the activity of ICDH. The results obtained were similar to those of GDH. (author)

Occurrence of specific influenza antibodies in saliva and nasal secretion of monkeys (Macacus rhesus) after oral administration of influenza vaccine inactivated by gamma rays

International Nuclear Information System (INIS)

Tischner, H.; Huyuh, P.L.; Phan, P.N.; Bergmann, K.C.; Hoang, T.N.; Luther, P.; Nordheim, W.; Braeuniger, S.; Waldman, R.H.

1984-01-01

Antibodies in nasal secretion and saliva were measured in 10 Macacus rhesus wich had been immunized orally with a 60 Co-gamma-inactivated influenza vaccine. Prior to immunization monkeys had no detectable antibodies against hemagglutinin (HA) and neuraminidase, resp. in sera or secretions. Oral immunization using intraoesophageal tubing, induced the occurrence of both antiobodies in pilocarpine-stimulated secretions within 28 days but not in sera. 6 monkeys reacted with increasing HA antibodies in nasal secretions and 10 monkeys with increasing neuraminidase antibodies. Salivary HA antibodies occurred in 8 of 10 and neuraminidase antibodies in 9 of 10 animals. In most cases antibodies occurred in both secretions simultaneously. These results demonstrate the stimulation of antibodies specific to influenza in the respiratory tract of monkeys after oral immunization with an inactivated vaccine, for the first time. (author)

Biochemical mechanism of action of a diketopiperazine inactivator of plasminogen activator inhibitor-1

DEFF Research Database (Denmark)

Einholm, Anja P; Pedersen, Katrine E; Wind, Troels

2003-01-01

-inactivated PAI-1 is inert to reaction with its target proteases and has a decreased susceptibility to non-target proteases, in spite of a generally increased proteolytic susceptibility of specific peptide bonds elsewhere in PAI-1. The properties of XR5118-inactivated PAI-1 were different from those of the so...

Domain IV voltage-sensor movement is both sufficient and rate limiting for fast inactivation in sodium channels.

Science.gov (United States)

Capes, Deborah L; Goldschen-Ohm, Marcel P; Arcisio-Miranda, Manoel; Bezanilla, Francisco; Chanda, Baron

2013-08-01

Voltage-gated sodium channels are critical for the generation and propagation of electrical signals in most excitable cells. Activation of Na(+) channels initiates an action potential, and fast inactivation facilitates repolarization of the membrane by the outward K(+) current. Fast inactivation is also the main determinant of the refractory period between successive electrical impulses. Although the voltage sensor of domain IV (DIV) has been implicated in fast inactivation, it remains unclear whether the activation of DIV alone is sufficient for fast inactivation to occur. Here, we functionally neutralize each specific voltage sensor by mutating several critical arginines in the S4 segment to glutamines. We assess the individual role of each voltage-sensing domain in the voltage dependence and kinetics of fast inactivation upon its specific inhibition. We show that movement of the DIV voltage sensor is the rate-limiting step for both development and recovery from fast inactivation. Our data suggest that activation of the DIV voltage sensor alone is sufficient for fast inactivation to occur, and that activation of DIV before channel opening is the molecular mechanism for closed-state inactivation. We propose a kinetic model of sodium channel gating that can account for our major findings over a wide voltage range by postulating that DIV movement is both necessary and sufficient for fast inactivation.

Post-irradiation inactivation, protection, and repair of the sulfhydryl enzyme malate synthase

International Nuclear Information System (INIS)

Durchschlag, H.; Zipper, P.

1985-01-01

Malate synthase from baker's yeast, a trimeric sulfhydryl enzyme with one essential sulfhydryl group per subunit, was inactivated by 2 kGy X-irradiation in air-saturated aqueous solution (enzyme concentration: 0.5 mg/ml). The radiation induced changes of enzymic activity were registered at about 0,30,60 h after irradiation. To elucidate the role of OH - , O 2 , and H 2 O 2 in the X-ray inactivation of the enzyme, experiments were performed in the absence of presence of different concentrations of specific additives (formate, superoxide dismutase, catalase). These additives were added to malate synthase solutions before or after X-irradiation. Moreover, repairs of inactivated malate synthase were initiated at about 0 or 30 h after irradiation by means of the sulfhydryl agent dithiothreitol. Experiments yielded the following results: 1. Irradiation of malate synthase in the absence of additives inactivated the enzyme immediately to a residual activity Asub(r)=3% (corresponding to a D 37 =0.6 kGy), and led to further slow inactivation in the post-irradiation phase. Repairs, initiated at different times after irradiation, restored enzymic activity considerably. The repair initiated at t=0 led to Asub(r)=21%; repairs started later on resulted in somewhat lower activities. The decay of reparability, however, was found to progress more slowly than post-irradiation inactivation itself. After completion of repair the activities of repaired samples did not decrease significantly. 2. The presence of specific additives during irradiation caused significant protective effects against primary inactivation. The protection by formate was very pronounced (e.g., Asub(r)=72% and D 37 =6 kGy for 100 mM formate). The presence of catalytic amounts of superoxide dismutase and/or catalase exhibited only minor effects, depending on the presence and concentration of formate. (orig.)

Effective inactivation of a wide range of viruses by pasteurization.

Science.gov (United States)

Gröner, Albrecht; Broumis, Connie; Fang, Randel; Nowak, Thomas; Popp, Birgit; Schäfer, Wolfram; Roth, Nathan J

2018-01-01

Careful selection and testing of plasma reduces the risk of blood-borne viruses in the starting material for plasma-derived products. Furthermore, effective measures such as pasteurization at 60°C for 10 hours have been implemented in the manufacturing process of therapeutic plasma proteins such as human albumin, coagulation factors, immunoglobulins, and enzyme inhibitors to inactivate blood-borne viruses of concern. A comprehensive compilation of the virus reduction capacity of pasteurization is presented including the effect of stabilizers used to protect the therapeutic protein from modifications during heat treatment. The virus inactivation kinetics of pasteurization for a broad range of viruses were evaluated in the relevant intermediates from more than 15 different plasma manufacturing processes. Studies were carried out under the routine manufacturing target variables, such as temperature and product-specific stabilizer composition. Additional studies were also performed under robustness conditions, that is, outside production specifications. The data demonstrate that pasteurization inactivates a wide range of enveloped and nonenveloped viruses of diverse physicochemical characteristics. After a maximum of 6 hours' incubation, no residual infectivity could be detected for the majority of enveloped viruses. Effective inactivation of a range of nonenveloped viruses, with the exception of nonhuman parvoviruses, was documented. Pasteurization is a very robust and reliable virus inactivation method with a broad effectiveness against known blood-borne pathogens and emerging or potentially emerging viruses. Pasteurization has proven itself to be a highly effective step, in combination with other complementary safety measures, toward assuring the virus safety of final product. © 2017 The Authors Transfusion published by Wiley Periodicals, Inc. on behalf of AABB.

Inactivation and stability of viral diagnostic reagents treated by gamma radiation

International Nuclear Information System (INIS)

White, L.A.; Freeman, C.Y.; Hall, H.E.; Forrester, B.D.

1990-01-01

The objective of this study was to apply the pertinent findings from gamma inactivation of virus infectivity to the production of high quality diagnostic reagents. A Gammacell 220 was used to subject 38 viruses grown in either susceptible tissue cultures or embryonated chicken eggs to various doses of gamma radiation from a cobalt-60 source. The radiation required to reduce viral infectivity was 0.42 to 3.7 megarads (Mrad). The effect of gamma treatment on the antigenic reactivity of reagents for the complement fixation (CF), hemagglutination (HA) and neuraminadase assays was determined. Influenza antigens inactivated with 1.7 Mrad displayed comparable potency, sensitivity, specificity and stability to those inactivated by standard procedures with beta-propiolactone (BPL). Significant inactivation of influenza N1 and B neuraminidase occurred with >2.4 Mrad radiation at temperatures above 4 0 C. All 38 viruses were inactivated, and CF or HA antigens were prepared successfully. Antigenic potency remained stable with all antigens for 3 years and with 83% after 5 years storage. Influenza HA antigens evaluated after 9 years of storage demonstrated 86% stability. Gamma radiation is safer than chemical inactivation procedures and is a reliable and effective replacement for BPL in preparing diagnostic reagents. (author)

Inactivation and stability of viral diagnostic reagents treated by gamma radiation

Energy Technology Data Exchange (ETDEWEB)

White, L A; Freeman, C Y; Hall, H E; Forrester, B D [Department of Health and Human Services, Atlanta, GA (USA)

1990-10-01

The objective of this study was to apply the pertinent findings from gamma inactivation of virus infectivity to the production of high quality diagnostic reagents. A Gammacell 220 was used to subject 38 viruses grown in either susceptible tissue cultures or embryonated chicken eggs to various doses of gamma radiation from a cobalt-60 source. The radiation required to reduce viral infectivity was 0.42 to 3.7 megarads (Mrad). The effect of gamma treatment on the antigenic reactivity of reagents for the complement fixation (CF), hemagglutination (HA) and neuraminadase assays was determined. Influenza antigens inactivated with 1.7 Mrad displayed comparable potency, sensitivity, specificity and stability to those inactivated by standard procedures with beta-propiolactone (BPL). Significant inactivation of influenza N1 and B neuraminidase occurred with >2.4 Mrad radiation at temperatures above 4{sup 0}C. All 38 viruses were inactivated, and CF or HA antigens were prepared successfully. Antigenic potency remained stable with all antigens for 3 years and with 83% after 5 years storage. Influenza HA antigens evaluated after 9 years of storage demonstrated 86% stability. Gamma radiation is safer than chemical inactivation procedures and is a reliable and effective replacement for BPL in preparing diagnostic reagents. (author).

Luteinizing hormone-releasing hormone inactivation by purified pituitary plasma membranes: effects of receptor-binding studies.

Science.gov (United States)

Clayton, R N; Shakespear, R A; Duncan, J A; Marshall, J C

1979-05-01

Inactivation of LHRH by purified bovine pituitary plasma membranes was studied in vitro. After incubation of [125I]iodo-LHRH with plasma membranes, the amount of tracer bound to the pellet was measured, and the integrity of the unbound tracer in the supernatant was assessed. Reduction in ability to bind to anti-LHRH serum and to rebind to plasma membranes together with altered electrophoretic mobility on polyacrylamide gels showed that the unbound [125I]iodo-LHRH was inactivated. LHRH inactivation occurred rapidly and was dependent upon membrane concentration and incubation temperature. These results indicate that hormone inactivation must be taken into account in the interpretation of LHRH-receptor interactions. During 37 C incubations, the apparent absence of specific LHRH binding can be explained by inactivation of tracer hormone. Significant LHRH inactivation also occurred at 0 C, which in part explains the insensitivity of LHRH receptor assays. Assessment of LHRH inactivation by different particulate subcellular fractions of pituitary tissue showed that the inactivating enzyme was associated with the plasma membranes; other organelles did not alter LHRH. The enzyme appeared to be an integral part of the plasma membrane structure, since enzymic activity could not be removed by washing without reducing specific LHRH binding. Additionally, reduction of LHRH inactivation by the inhibitors Bacitracin and Trasylol and by magnesium was also accompanied by reduced LHRH binding. Previous studies have shown that the majority of LHRH binding to pituitary plasma membranes is to the low affinity site (approximately 10(-6) M), but the significance of this binding has been uncertain. Our findings indicate that low affinity binding probably represents binding of LHRH to the inactivating enzyme. The LHRH analog, D-Ser6(TBu), des Gly10, ethylamide, has greater biological activity than LHRH and is not inactivated to a significant extent by pituitary plasma membranes. The

THE USE OF THE ANTI-VENOM SPECIFIC ANTIBODIES ISOLATED FROM DUCK EGGS FOR INACTIVATION OF THE VIPER VENOM

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ADRIANA CRISTE

2008-05-01

Full Text Available The activity of specific anti-venom can be demonstrated using protection test in laboratory mice. Our study aimed to emphasize the possibility of viper venom inactivation by the antibodies produced and isolated from duck eggs and also to the activation concentration of these antibodies. The venom used for inoculation was harvested from two viper species (Vipera ammodytes and Vipera berus. The immunoglobulin extract had a better activity on the venom from Vipera berus compared to the venom from Vipera ammodytes. This could be the result of a better immunological response, as consequence of the immunization with this type of venom, compared to the response recorded when the Vipera ammodytes venom was used. Besides the advantages of low cost, high productivity and reduced risk of anaphylactic shock, the duck eggs also have high activity up to dilutions of 1/16, 1/32, respectively, with specific activity and 100 surviving in individuals which received 3 x DL50.

Skewed X-inactivation in cloned mice

International Nuclear Information System (INIS)

Senda, Sho; Wakayama, Teruhiko; Yamazaki, Yukiko; Ohgane, Jun; Hattori, Naka; Tanaka, Satoshi; Yanagimachi, Ryuzo; Shiota, Kunio

2004-01-01

In female mammals, dosage compensation for X-linked genes is accomplished by inactivation of one of two X chromosomes. The X-inactivation ratio (a percentage of the cells with inactivated maternal X chromosomes in the whole cells) is skewed as a consequence of various genetic mutations, and has been observed in a number of X-linked disorders. We previously reported that phenotypically normal full-term cloned mouse fetuses had loci with inappropriate DNA methylation. Thus, cloned mice are excellent models to study abnormal epigenetic events in mammalian development. In the present study, we analyzed X-inactivation ratios in adult female cloned mice (B6C3F1). Kidneys of eight naturally produced controls and 11 cloned mice were analyzed. Although variations in X-inactivation ratio among the mice were observed in both groups, the distributions were significantly different (Ansary-Bradley test, P < 0.01). In particular, 2 of 11 cloned mice showed skewed X-inactivation ratios (19.2% and 86.8%). Similarly, in intestine, 1 of 10 cloned mice had a skewed ratio (75.7%). Skewed X-inactivation was observed to various degrees in different tissues of different individuals, suggesting that skewed X-inactivation in cloned mice is the result of secondary cell selection in combination with stochastic distortion of primary choice. The present study is the first demonstration that skewed X-inactivation occurs in cloned animals. This finding is important for understanding both nuclear transfer technology and etiology of X-linked disorders

Free radical inactivation of trypsin

International Nuclear Information System (INIS)

Cudina, Ivana; Jovanovic, S.V.

1988-01-01

Reactivities of free radical oxidants, radical OH, Br2-anion radical and Cl 3 COO radical and a reductant, CO2-anion radical, with trypsin and reactive protein components were determined by pulse radiolysis of aqueous solutions at pH 7, 20 0 C. Highly reactive free radicals, radical OH, Br2-anion radical and CO2-anion radical, react with trypsin at diffusion controlled rates. Moderately reactive trichloroperoxy radical, k(Cl 3 COO radical + trypsin) preferentially oxidizes histidine residues. The efficiency of inactivation of trypsin by free radicals is inversely proportional to their reactivity. The yields of inactivation of trypsin by radical OH, Br2-anion radical and CO2-anion radical are low, G(inactivation) = 0.6-0.8, which corresponds to ∼ 10% of the initially produced radicals. In contrast, Cl 3 COO radical inactivates trypsin with ∼ 50% efficiency, i.e. G(inactivation) = 3.2. (author)

Active-site-directed inactivation of Aspergillus oryzae beta-galactosidase with beta-D-galactopyranosylmethyl-p-nitrophenyltriazene.

Science.gov (United States)

Mega, T; Nishijima, T; Ikenaka, T

1990-04-01

beta-D-Galactopyranosylmethyl-p-nitrophenyltriazene (beta-GalMNT), a specific inhibitor of beta-galactosidase, was isolated as crystals by HPLC and its chemical and physicochemical characteristics were examined. Aspergillus oryzae beta-galactosidase was inactivated by the compound. We studied the inhibition mechanism in detail. The inhibitor was hydrolyzed by the enzyme to p-nitroaniline and an active intermediate (beta-galactopyranosylmethyl carbonium or beta-galactopyranosylmethyldiazonium), which inactivated the enzyme. The efficiency of inactivation of the enzyme (the ratio of moles of inactivated enzyme to moles of beta-GalMNT hydrolyzed by the enzyme) was 3%; the efficiency of Escherichia coli beta-galactosidase was 49%. In spite of the low efficiency, the rate of inactivation of A. oryzae enzyme was not very different from that of the E. coli enzyme, because the former hydrolyzed beta-GalMNT faster than the latter did. A. oryzae beta-galactosidase was also inactivated by p-chlorophenyl, p-tolyl, and m-nitrophenyl derivatives of beta-galactopyranosylmethyltriazene. However, E. coli beta-galactosidase was not inactivated by these triazene derivatives. The results showed that the inactivation of A. oryzae and E. coli beta-galactosidases by beta-GalMNT was an enzyme-activated and active-site-directed irreversible inactivation. The possibility of inactivation by intermediates produced nonenzymatically was ruled out for E. coli, but not for the A. oryzae enzyme.

Strategy to inactivate Clostridium perfringens spores in meat products.

Science.gov (United States)

Akhtar, Saeed; Paredes-Sabja, Daniel; Torres, J Antonio; Sarker, Mahfuzur R

2009-05-01

The current study aimed to develop an inactivation strategy for Clostridium perfringens spores in meat through a combination of spore activation at low pressure (100-200 MPa, 7 min) and elevated temperature (80 degrees C, 10 min); spore germination at high temperatures (55, 60 or 65 degrees C); and inactivation of germinated spores with elevated temperatures (80 and 90 degrees C, 10 and 20 min) and high pressure (586 MPa, at 23 and 73 degrees C, 10 min). Low pressures (100-200 MPa) were insufficient to efficiently activate C. perfringens spores for germination. However, C. perfringens spores were efficiently activated with elevated temperature (80 degrees C, 10 min), and germinated at temperatures lethal for vegetative cells (>or= 55 degrees C) when incubated for 60 min with a mixture of L-asparagine and KCl (AK) in phosphate buffer (pH 7) and in poultry meat. Inactivation of spores (approximately 4 decimal reduction) in meat by elevated temperatures (80-90 degrees C for 20 min) required a long germination period (55 degrees C for 60 min). However, similar inactivation level was reached with shorter germination period (55 degrees C for 15 min) when spore contaminated-meat was treated with pressure-assisted thermal processing (568 MPa, 73 degrees C, 10 min). Therefore, the most efficient strategy to inactivate C. perfringens spores in poultry meat containing 50 mM AK consisted: (i) a primary heat treatment (80 degrees C, 10 min) to pasteurize and denature the meat proteins and to activate C. perfringens spores for germination; (ii) cooling of the product to 55 degrees C in about 20 min and further incubation at 55 degrees C for about 15 min for spore germination; and (iii) inactivation of germinated spores by pressure-assisted thermal processing (586 MPa at 73 degrees C for 10 min). Collectively, this study demonstrates the feasibility of an alternative and novel strategy to inactivate C. perfringens spores in meat products formulated with germinants specific for C

Development of inactivated-local isolate vaccine for infectious bronchitis

Directory of Open Access Journals (Sweden)

Darminto

1999-06-01

Full Text Available Infectious bronchitis (IB is an acute highly contagious viral respiratory disease of poultry caused by coronavirus. The disease causes high mortality in young chicks, reduce body weight gain in broilers and remarkable drop in egg production. IB can only be controlled by vaccination, but due to the antigenic variation among serotypes of IB viruses, the effective IB vaccine should be prepared from local isolates. The aim of this research is to develop inactivated IB vaccine derived from local IB isolates. Local isolates of IB viruses designated as I-37, I-269 and PTS-III were propagated respectively in specific pathogen free (SPF chicken eggs, the viruses then were inactivated by formaline at final concentration of 1:1,000. Subsequently, the inactivated viruses were mixed and emulsified in oil emulsion adjuvant with sorbitant mono-oleic as an emulsifier. The vaccine then was tested for its safety, potency and efficacy in broiler chickens. Birds inoculated twice with a two-week interval by inactivated vaccine did not show any adverse reaction, either systemic or local reaction. The inoculated birds developed antibody responses with high titre, while antibody of the control birds remain negative. In addition, efficacy test which was conducted in broilers demonstrated that birds vaccinated by live-commercial vaccine and boosted three weeks later by Balitvet inactivated vaccine showed high level of antibody production which provided high level of protection against challenged virus (76% against I-37, 92% against I-269 and 68% against PTS-III challenge viruses. From this study, it can be concluded that inactivated local IB vaccine is considered to be safe, potent and efficacious. The vaccine stimulates high titre of antibody responses, which provide high level of protection against challenged viruses.

Increasing the endogenous NO level causes catalase inactivation and reactivation of intercellular apoptosis signaling specifically in tumor cells.

Science.gov (United States)

Bauer, Georg

2015-12-01

Tumor cells generate extracellular superoxide anions and are protected against intercellular apoptosis-inducing HOCl- and NO/peroxynitrite signaling through the expression of membrane-associated catalase. This enzyme decomposes H2O2 and thus prevents HOCl synthesis. It efficiently interferes with NO/peroxynitrite signaling through oxidation of NO and decomposition of peroxynitrite. The regulatory potential of catalase at the crosspoint of ROS and RNS chemical biology, as well as its high local concentration on the outside of the cell membrane of tumor cells, establish tight control of intercellular signaling and thus prevent tumor cell apoptosis. Therefore, inhibition of catalase or its inactivation by singlet oxygen reactivate intercellular apoptosis-inducing signaling. Nitric oxide and peroxynitrite are connected with catalase in multiple and meaningful ways, as (i) NO can be oxidated by compound I of catalase, (ii) NO can reversibly inhibit catalase, (iii) peroxynitrite can be decomposed by catalase and (iv) the interaction between peroxynitrite and H2O2 leads to the generation of singlet oxygen that inactivates catalase. Therefore, modulation of the concentration of free NO through addition of arginine, inhibition of arginase, induction of NOS expression or inhibition of NO dioxygenase triggers an autoamplificatory biochemical cascade that is based on initial formation of singlet oxygen, amplification of superoxide anion/H2O2 and NO generation through singlet oxygen dependent stimulation of the FAS receptor and caspase-8. Finally, singlet oxygen is generated at sufficiently high concentration to inactivate protective catalase and to reactivate intercellular apoptosis-inducing ROS signaling. This regulatory network allows to establish several pathways for synergistic interactions, like the combination of modulators of NO metabolism with enhancers of superoxide anion generation, modulators of NO metabolism that act at different targets and between modulators of

Increasing the endogenous NO level causes catalase inactivation and reactivation of intercellular apoptosis signaling specifically in tumor cells

Science.gov (United States)

Bauer, Georg

2015-01-01

Tumor cells generate extracellular superoxide anions and are protected against intercellular apoptosis-inducing HOCl- and NO/peroxynitrite signaling through the expression of membrane-associated catalase. This enzyme decomposes H2O2 and thus prevents HOCl synthesis. It efficiently interferes with NO/peroxynitrite signaling through oxidation of NO and decomposition of peroxynitrite. The regulatory potential of catalase at the crosspoint of ROS and RNS chemical biology, as well as its high local concentration on the outside of the cell membrane of tumor cells, establish tight control of intercellular signaling and thus prevent tumor cell apoptosis. Therefore, inhibition of catalase or its inactivation by singlet oxygen reactivate intercellular apoptosis-inducing signaling. Nitric oxide and peroxynitrite are connected with catalase in multiple and meaningful ways, as (i) NO can be oxidated by compound I of catalase, (ii) NO can reversibly inhibit catalase, (iii) peroxynitrite can be decomposed by catalase and (iv) the interaction between peroxynitrite and H2O2 leads to the generation of singlet oxygen that inactivates catalase. Therefore, modulation of the concentration of free NO through addition of arginine, inhibition of arginase, induction of NOS expression or inhibition of NO dioxygenase triggers an autoamplificatory biochemical cascade that is based on initial formation of singlet oxygen, amplification of superoxide anion/H2O2 and NO generation through singlet oxygen dependent stimulation of the FAS receptor and caspase-8. Finally, singlet oxygen is generated at sufficiently high concentration to inactivate protective catalase and to reactivate intercellular apoptosis-inducing ROS signaling. This regulatory network allows to establish several pathways for synergistic interactions, like the combination of modulators of NO metabolism with enhancers of superoxide anion generation, modulators of NO metabolism that act at different targets and between modulators of

Acute Vhl gene inactivation induces cardiac HIF-dependent erythropoietin gene expression.

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Marta Miró-Murillo

Full Text Available Von Hippel Lindau (Vhl gene inactivation results in embryonic lethality. The consequences of its inactivation in adult mice, and of the ensuing activation of the hypoxia-inducible factors (HIFs, have been explored mainly in a tissue-specific manner. This mid-gestation lethality can be also circumvented by using a floxed Vhl allele in combination with an ubiquitous tamoxifen-inducible recombinase Cre-ER(T2. Here, we characterize a widespread reduction in Vhl gene expression in Vhl(floxed-UBC-Cre-ER(T2 adult mice after dietary tamoxifen administration, a convenient route of administration that has yet to be fully characterized for global gene inactivation. Vhl gene inactivation rapidly resulted in a marked splenomegaly and skin erythema, accompanied by renal and hepatic induction of the erythropoietin (Epo gene, indicative of the in vivo activation of the oxygen sensing HIF pathway. We show that acute Vhl gene inactivation also induced Epo gene expression in the heart, revealing cardiac tissue to be an extra-renal source of EPO. Indeed, primary cardiomyocytes and HL-1 cardiac cells both induce Epo gene expression when exposed to low O(2 tension in a HIF-dependent manner. Thus, as well as demonstrating the potential of dietary tamoxifen administration for gene inactivation studies in UBC-Cre-ER(T2 mouse lines, this data provides evidence of a cardiac oxygen-sensing VHL/HIF/EPO pathway in adult mice.

Radiobiological inactivation of Epstein-Barr virus

International Nuclear Information System (INIS)

Henderson, E.; Heston, L.; Grogan, E.; Miller, G.

1978-01-01

Lymphocyte transforming properties of B95-8 strain Epstein-Barr virus (EBV) are very sensitive to inactivation by either uv or x irradiation. No dose of irradiation increases the transforming capacity of EBV. The x-ray dose needed for inactivation of EBV transformation (dose that results in 37% survival, 60,000 rads) is similar to the dose required for inactivation of plaque formation by herpes simplex virus type 1 (Fischer strain). Although herpes simplex virus is more sensitive than EBV to uv irradiation, this difference is most likely due to differences in the kinetics or mechanisms of repair of uv damage to the two viruses. The results lead to the hypothesis that a large part, or perhaps all, of the EBV genome is in some way needed to initiate transformation. The abilities of EBV to stimulate host cell DNA synthesis, to induce nuclear antigen, and to immortalize are inactivated in parallel. All clones of marmoset cells transformed by irradiated virus produce extracellular transforming virus. These findings suggest that the abilities of the virus to transform and to replicate complete progeny are inactivated together. The amounts of uv and x irradiation that inactivate transformation by B95-8 virus are less than the dose needed to inactivate early antigen induction by the nontransforming P 3 HR-1 strain of EBV. Based on radiobiological inactivation, 10 to 50% of the genome is needed for early antigen induction

Studies on the inactivation of human parvovirus 4.

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Baylis, Sally A; Tuke, Philip W; Miyagawa, Eiji; Blümel, Johannes

2013-10-01

Human parvovirus 4 (PARV4) is a novel parvovirus, which like parvovirus B19 (B19V) can be a contaminant of plasma pools used to prepare plasma-derived medicinal products. Inactivation studies of B19V have shown that it is more sensitive to virus inactivation strategies than animal parvoviruses. However, inactivation of PARV4 has not yet been specifically addressed. Treatment of parvoviruses by heat or low-pH conditions causes externalization of the virus genome. Using nuclease treatment combined with real-time polymerase chain reaction, the extent of virus DNA externalization was used as an indirect measure of the inactivation of PARV4, B19V, and minute virus of mice (MVM) by pasteurization of albumin and by low-pH treatment. Infectivity studies were performed in parallel for B19V and MVM. PARV4 showed greater resistance to pasteurization and low-pH treatment than B19V, although PARV4 was not as resistant as MVM. There was a 2- to 3-log reduction of encapsidated PARV4 DNA after pasteurization and low-pH treatment. In contrast, B19V was effectively inactivated while MVM was stable under these conditions. Divalent cations were found to have a stabilizing effect on PARV4 capsids. In the absence of divalent cations, even at neutral pH, there was a reduction of PARV4 titer, an effect not observed for B19V or MVM. In the case of heat treatment and incubation at low pH, PARV4 shows intermediate resistance when compared to B19V and MVM. Divalent cations seem important for stabilizing PARV4 virus particles. © 2013 American Association of Blood Banks.

Chlorine inactivation of Tubifex tubifex in drinking water and the synergistic effect of sequential inactivation with UV irradiation and chlorine.

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Nie, Xiao-Bao; Li, Zhi-Hong; Long, Yuan-Nan; He, Pan-Pan; Xu, Chao

2017-06-01

The inactivation of Tubifex tubifex is important to prevent contamination of drinking water. Chlorine is a widely-used disinfectant and the key factor in the inactivation of T. tubifex. This study investigated the inactivation kinetics of chlorine on T. tubifex and the synergistic effect of the sequential use of chlorine and UV irradiation. The experimental results indicated that the Ct (concentration × time reaction ) concept could be used to evaluate the inactivation kinetics of T. tubifex with chlorine, thus allowing for the use of a simpler Ct approach for the assessment of T. tubifex chlorine inactivation requirements. The inactivation kinetics of T. tubifex by chlorine was found to be well-fitted to a delayed pseudo first-order Chick-Watson expression. Sequential experiments revealed that UV irradiation and chlorine worked synergistically to effectively inactivate T. tubifex as a result of the decreased activation energy, E a , induced by primary UV irradiation. Furthermore, the inactivation effectiveness of T. tubifex by chlorine was found to be affected by several drinking water quality parameters including pH, turbidity, and chemical oxygen demand with potassium permanganate (COD Mn ) concentration. High pH exhibited pronounced inactivation effectiveness and the decrease in turbidity and COD Mn concentrations contributed to the inactivation of T. tubifex. Copyright © 2017 Elsevier Ltd. All rights reserved.

Generation and characterization of rat and mouse monoclonal antibodies specific for MeCP2 and their use in X-inactivation studies.

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K Laurence Jost

Full Text Available Methyl CpG binding protein 2 (MeCP2 binds DNA, and has a preference for methylated CpGs and, hence, in cells, it accumulates in heterochromatin. Even though it is expressed ubiquitously MeCP2 is particularly important during neuronal maturation. This is underscored by the fact that in Rett syndrome, a neurological disease, 80% of patients carry a mutation in the MECP2 gene. Since the MECP2 gene lies on the X chromosome and is subjected to X chromosome inactivation, affected patients are usually chimeric for wild type and mutant MeCP2. Here, we present the generation and characterization of the first rat monoclonal MeCP2 specific antibodies as well as mouse monoclonal antibodies and a rabbit polyclonal antibody. We demonstrate that our antibodies are suitable for immunoblotting, (chromatin immunoprecipitation and immunofluorescence of endogenous and ectopically expressed MeCP2. Epitope mapping revealed that most of the MeCP2 monoclonal antibodies recognize the C-terminal domain and one the N-terminal domain of MeCP2. Using slot blot analysis, we determined a high sensitivity of all antibodies, detecting amounts as low as 1 ng of MeCP2 protein. Moreover, the antibodies recognize MeCP2 from different species, including human, mouse, rat and pig. Lastly, we have validated their use by analyzing and quantifying X chromosome inactivation skewing using brain tissue of MeCP2 heterozygous null female mice. The new MeCP2 specific monoclonal antibodies described here perform well in a large variety of immunological applications making them a very valuable set of tools for studies of MeCP2 pathophysiology in situ and in vitro.

recA+-dependent inactivation of the lambda repressor in Escherichia coli lysogens by γ-radiation and by tif expression

International Nuclear Information System (INIS)

West, S.C.; Powell, K.A.; Emmerson, P.T.

1975-01-01

When lambda lysogens of E. coli are induced by γ-radiation the lambda repressor, as measured by its specific binding to lambda DNA, is rapidly inactivated by a recA + -dependent process which does not require new protein synthesis. This rapid inactivation is similar to inactivation of repressor by expression of the temperature sensitive E. coli mutation tif. In contrast, induction by UV irradiation or mitomycin C treatment requires new protein synthesis and there is a lag before the repressor is inactivated (Tomizawa and Ogawa, 1967; Shinagawa and Itoh, 1973). (orig.) [de

DNA aptamer functionalized gold nanostructures for molecular recognition and photothermal inactivation of methicillin-Resistant Staphylococcus aureus.

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Ocsoy, Ismail; Yusufbeyoglu, Sadi; Yılmaz, Vedat; McLamore, Eric S; Ildız, Nilay; Ülgen, Ahmet

2017-11-01

In this work, we report the development of DNA aptamer-functionalized gold nanoparticles (Apt@Au NPs) and gold nanorods (Apt@Au NRs) for inactivation of Methicillin-resistant Staphylococcus aureus (MRSA) with targeted photothermal therapy (PTT). Although both Apt@Au NPs and Apt@Au NRs specifically bind to MRSA cells, Apt@Au NPs and Apt@Au NRs inactivated ∼5% and over 95% of the cells,respectively through PTT. This difference in inactivation was based on the relatively high longitudinal absorption of near-infrared (NIR) radiation and strong photothermal conversion capability for the Apt@Au NRs compared to the Apt@Au NPs. The Au NRs served as a nanoplatform for the loading of thiolated aptamer and also provided multivalent effects for increasing binding strength and affinity to MRSA. Our results indicate that the type of aptamer and the degree of multivalent effect(s) are important factors for MRSA inactivation efficiency in PTT. We show that the Apt@Au NRs are a very effective and promising nanosystem for specific cell recognition and in vitro PTT. Copyright © 2017 Elsevier B.V. All rights reserved.

Female meiotic sex chromosome inactivation in chicken.

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Sam Schoenmakers

2009-05-01

Full Text Available During meiotic prophase in male mammals, the heterologous X and Y chromosomes remain largely unsynapsed, and meiotic sex chromosome inactivation (MSCI leads to formation of the transcriptionally silenced XY body. In birds, the heterogametic sex is female, carrying Z and W chromosomes (ZW, whereas males have the homogametic ZZ constitution. During chicken oogenesis, the heterologous ZW pair reaches a state of complete heterologous synapsis, and this might enable maintenance of transcription of Z- and W chromosomal genes during meiotic prophase. Herein, we show that the ZW pair is transiently silenced, from early pachytene to early diplotene using immunocytochemistry and gene expression analyses. We propose that ZW inactivation is most likely achieved via spreading of heterochromatin from the W on the Z chromosome. Also, persistent meiotic DNA double-strand breaks (DSBs may contribute to silencing of Z. Surprisingly, gammaH2AX, a marker of DSBs, and also the earliest histone modification that is associated with XY body formation in mammalian and marsupial spermatocytes, does not cover the ZW during the synapsed stage. However, when the ZW pair starts to desynapse, a second wave of gammaH2AX accumulates on the unsynapsed regions of Z, which also show a reappearance of the DSB repair protein RAD51. This indicates that repair of meiotic DSBs on the heterologous part of Z is postponed until late pachytene/diplotene, possibly to avoid recombination with regions on the heterologously synapsed W chromosome. Two days after entering diplotene, the Z looses gammaH2AX and shows reactivation. This is the first report of meiotic sex chromosome inactivation in a species with female heterogamety, providing evidence that this mechanism is not specific to spermatogenesis. It also indicates the presence of an evolutionary force that drives meiotic sex chromosome inactivation independent of the final achievement of synapsis.

Inactivation of adipose angiotensinogen reduces adipose tissue macrophages and increases metabolic activity.

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LeMieux, Monique J; Ramalingam, Latha; Mynatt, Randall L; Kalupahana, Nishan S; Kim, Jung Han; Moustaïd-Moussa, Naïma

2016-02-01

The adipose renin-angiotensin system (RAS) has been linked to obesity-induced inflammation, though mechanisms are not completely understood. In this study, adipose-specific angiotensinogen knockout mice (Agt-KO) were generated to determine whether Agt inactivation reduces inflammation and alters the metabolic profile of the Agt-KO mice compared to wild-type (WT) littermates. Adipose tissue-specific Agt-KO mice were created using the Cre-LoxP system with both Agt-KO and WT littermates fed either a low-fat or high-fat diet to assess metabolic changes. White adipose tissue was used for gene/protein expression analyses and WAT stromal vascular cells for metabolic extracellular flux assays. No significant differences were observed in body weight or fat mass between both genotypes on either diet. However, improved glucose clearance was observed in Agt-KO compared to WT littermates, consistent with higher expression of genes involved in insulin signaling, glucose transport, and fatty acid metabolism. Furthermore, Agt inactivation reduced total macrophage infiltration in Agt-KO mice fed both diets. Lastly, stroma vascular cells from Agt-KO mice revealed higher metabolic activity compared to WT mice. These findings indicate that adipose-specific Agt inactivation leads to reduced adipose inflammation and increased glucose tolerance mediated in part via increased metabolic activity of adipose cells. © 2015 The Obesity Society.

Complete inactivation of HIV-1 using photo-labeled non-nucleoside reverse transcriptase inhibitors.

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Rios, Adan; Quesada, Jorge; Anderson, Dallas; Goldstein, Allan; Fossum, Theresa; Colby-Germinario, Susan; Wainberg, Mark A

2011-01-01

We demonstrate that a photo-labeled derivative of the non-nucleoside reverse transcriptase inhibitor (NNRTI) dapivirine termed DAPY, when used together with exposure to ultraviolet light, was able to completely and irreversibly inactivate both HIV-1 RT activity as well as infectiousness in each of a T cell line and peripheral blood mononuclear cells. Control experiments using various concentrations of DAPY revealed that a combination of exposure to ultraviolet light together with use of the specific, high affinity photo-labeled compound was necessary for complete inactivation to occur. This method of HIV RT inactivation may have applicability toward preservation of an intact viral structure and warrants further investigation in regard to the potential of this approach to elicit a durable, broad protective immune response. Copyright © 2010 Elsevier B.V. All rights reserved.

Photodynamic Inactivation of Mammalian Viruses and Bacteriophages

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Liliana Costa

2012-06-01

Full Text Available Photodynamic inactivation (PDI has been used to inactivate microorganisms through the use of photosensitizers. The inactivation of mammalian viruses and bacteriophages by photosensitization has been applied with success since the first decades of the last century. Due to the fact that mammalian viruses are known to pose a threat to public health and that bacteriophages are frequently used as models of mammalian viruses, it is important to know and understand the mechanisms and photodynamic procedures involved in their photoinactivation. The aim of this review is to (i summarize the main approaches developed until now for the photodynamic inactivation of bacteriophages and mammalian viruses and, (ii discuss and compare the present state of the art of mammalian viruses PDI with phage photoinactivation, with special focus on the most relevant mechanisms, molecular targets and factors affecting the viral inactivation process.

9 CFR 113.100 - General requirements for inactivated bacterial products.

Science.gov (United States)

2010-01-01

... instances, the guinea pig safety test provided in § 113.38 shall be conducted in place of the mouse safety... Outline of Production, an inactivated bacterial product shall meet the applicable requirements in this... in poultry as defined in the specific Standard Requirement or Outline of Production for the product...

Microbial Inactivation by Ultrasound Assisted Supercritical Fluids

Science.gov (United States)

Benedito, Jose; Ortuño, Carmen; Castillo-Zamudio, Rosa Isela; Mulet, Antonio

A method combining supercritical carbon dioxide (SC-CO2) and high power ultrasound (HPU) has been developed and tested for microbial/enzyme inactivation purposes, at different process conditions for both liquid and solid matrices. In culture media, using only SC-CO2, the inactivation rate of E. coli and S. cerevisiae increased with pressure and temperature; and the total inactivation (7-8 log-cycles) was attained after 25 and 140 min of SC-CO2 (350 bar, 36 °C) treatment, respectively. Using SC-CO2+HPU, the time for the total inactivation of both microorganisms was reduced to only 1-2 min, at any condition selected. The SC-CO2+HPU inactivation of both microorganisms was slower in juices (avg. 4.9 min) than in culture media (avg. 1.5 min). In solid samples (chicken, turkey ham and dry-cured pork cured ham) treated with SC-CO2 and SC-CO2+HPU, the inactivation rate of E. coli increased with temperature. The application of HPU to the SC-CO2 treatments accelerated the inactivation rate of E. coli and that effect was more pronounced in treatments with isotonic solution surrounding the solid food samples. The application of HPU enhanced the SC-CO2 inactivation mechanisms of microorganisms, generating a vigorous agitation that facilitated the CO2 solubilization and the mass transfer process. The cavitation generated by HPU could damage the cell walls accelerating the extraction of vital constituents and the microbial death. Thus, using the combined technique, reasonable industrial processing times and mild process conditions could be used which could result into a cost reduction and lead to the minimization in the food nutritional and organoleptic changes.

Charge immobilization of the voltage sensor in domain IV is independent of sodium current inactivation.

Science.gov (United States)

Sheets, Michael F; Hanck, Dorothy A

2005-02-15

Recovery from fast inactivation in voltage-dependent Na+ channels is associated with a slow component in the time course of gating charge during repolarization (i.e. charge immobilization), which results from the slow movement of the S4 segments in domains III and IV (S4-DIII and S4-DIV). Previous studies have shown that the non-specific removal of fast inactivation by the proteolytic enzyme pronase eliminated charge immobilization, while the specific removal of fast inactivation (by intracellular MTSET modification of a cysteine substituted for the phenylalanine in the IFM motif, ICMMTSET, in the inactivation particle formed by the linker between domains III and IV) only reduced the amount of charge immobilization by nearly one-half. To investigate the molecular origin of the remaining slow component of charge immobilization we studied the human cardiac Na+ channel (hH1a) in which the outermost arginine in the S4-DIV, which contributes approximately 20% to total gating charge (Qmax), was mutated to a cysteine (R1C-DIV). Gating charge could be fully restored in R1C-DIV by exposure to extracellular MTSEA, a positively charged methanethiosulphonate reagent. The RIC-DIV mutation was combined with ICMMTSET to remove fast inactivation, and the gating currents of R1C-DIV-ICM(MTSET) were recorded before and after modification with MTSEAo. Prior to MTSEAo, the time course of the gating charge during repolarization (off-charge) was best described by a single fast time constant. After MTSEA, the off-charge had both fast and slow components, with the slow component accounting for nearly 35% of Qmax. These results demonstrate that the slow movement of the S4-DIV during repolarization is not dependent upon the normal binding of the inactivation particle.

Patulin reduction in apple juice by inactivated Alicyclobacillus spp.

Science.gov (United States)

Yuan, Y; Wang, X; Hatab, S; Wang, Z; Wang, Y; Luo, Y; Yue, T

2014-12-01

This study aimed to investigate the reduction of patulin (PAT) in apple juice by 12 inactivated Alicyclobacillus strains. The reduction rate of PAT by each strain was determined by high-performance liquid chromatography (HPLC). The results indicated that the removal of PAT was strain specific. Alicyclobacillus acidoterrestris 92 and A. acidoterrestris 96 were the most effective ones among the 12 tested strains in the removal of PAT. Therefore, these two strains were selected to study the effects of incubation time, initial PAT concentration and bacteria powder amount on PAT removal abilities of Alicyclobacillus. The highest PAT reduction rates of 88·8 and 81·6% were achieved after 24-h incubation with initial PAT concentration of 100 μg l(-1) and bacteria powder amount of 40 g l(-1) , respectively. Moreover, it was found that the treatment by these 12 inactivated Alicyclobacillus strains had no negative effect on the quality parameters of apple juice. Similar assays were performed in supermarket apple juice, where inactivated Alicyclobacillus cells could efficiently reduce PAT content. Taken together, these data suggest the possible application of this strategy as a means to detoxify PAT-contaminated juices. Inactivated Alicyclobacillus cells can efficiently reduce patulin concentration in apple juice. It provides a theoretical foundation for recycling of Alicyclobacillus cells from spoiled apple juice to reduce the source of pollution and the cost of juice industry. This is the first report on the use of Alicyclobacillus to remove patulin from apple juice. © 2014 The Society for Applied Microbiology.

Enhancing immune responses to inactivated porcine parvovirus oil emulsion vaccine by co-inoculating porcine transfer factor in mice.

Science.gov (United States)

Wang, Rui-ning; Wang, Ya-bin; Geng, Jing-wei; Guo, Dong-hui; Liu, Fang; Chen, Hong-ying; Zhang, Hong-ying; Cui, Bao-an; Wei, Zhan-yong

2012-07-27

Inactivated porcine parvovirus (PPV) vaccines are available commercially and widely used in the breeding herds. However, inactivated PPV vaccines have deficiencies in induction of specific cellular immune response. Transfer factor (TF) is a material that obtained from the leukocytes, and is a novel immune-stimulatory reagent that as a modulator of the immune system. In this study, the immunogenicity of PPV oil emulsion vaccine and the immuno-regulatory activities of TF were investigated. The inactivated PPV oil emulsion vaccines with or without TF were inoculated into BALB/c mice by subcutaneous injection. Then humoral and cellular immune responses were evaluated by indirect enzyme-linked immunosorbent assays (ELISA), fluorescence-activated cell sorter analyses (FACS). The results showed that the PPV specific immune responses could be evoked in mice by inoculating with PPV oil emulsion vaccine alone or by co-inoculation with TF. The cellular immune response levels in the co-inoculation groups were higher than those groups receiving the PPV oil emulsion vaccine alone, with the phenomena of higher level of IFN-γ, a little IL-6 and a trace of IL-4 in serum, and a vigorous T-cell response. However, there was no significant difference in antibody titers between TF synergy inactivated vaccine and the inactivated vaccine group (P>0.05). In conclusion, these results suggest that TF possess better cellular immune-enhancing capability and would be exploited into an effective immune-adjuvant for inactivated vaccines. Copyright © 2012 Elsevier Ltd. All rights reserved.

Ultraviolet inactivation of papain

International Nuclear Information System (INIS)

Baugher, J.F.; Grossweiner, L.I.

1975-01-01

Flash photolysis transient spectra (lambda > 250 nm) of aqueous papain showed that the initial products are the neutral tryptophan radical Trp (lambdasub(max) 510 nm), the tryptophan triplet state 3 Trp (lambdasub(max) 460 nm), the disulfide bridge electron adduct -SS - - (lambdasub(max) 420 nm) and the hydrated electron esub(aq) - . The -SS - - yield was not altered by nitrous oxide or air, indicating that the formation of this product does not involve electrons in the external medium. The original papain preparation was activated by irradiating under nitrogen. The action spectrum supports previous work attributing the low initial activity to blocking of cysteinyl site 25 with a mixed disulfide. Flask lamp irradiation in nitrogen led to activation at low starting activities and inactivation at higher starting activities, while only inactivation at the same quantum yield was observed with air saturation. The results are consistent with photoionization of an essential tryptophyl residue as the key inactivating step. (author)

Pathogens Inactivated by Low-Energy-Electron Irradiation Maintain Antigenic Properties and Induce Protective Immune Responses

Science.gov (United States)

Fertey, Jasmin; Bayer, Lea; Grunwald, Thomas; Pohl, Alexandra; Beckmann, Jana; Gotzmann, Gaby; Casado, Javier Portillo; Schönfelder, Jessy; Rögner, Frank-Holm; Wetzel, Christiane; Thoma, Martin; Bailer, Susanne M.; Hiller, Ekkehard; Rupp, Steffen; Ulbert, Sebastian

2016-01-01

Inactivated vaccines are commonly produced by incubating pathogens with chemicals such as formaldehyde or β-propiolactone. This is a time-consuming process, the inactivation efficiency displays high variability and extensive downstream procedures are often required. Moreover, application of chemicals alters the antigenic components of the viruses or bacteria, resulting in reduced antibody specificity and therefore stimulation of a less effective immune response. An alternative method for inactivation of pathogens is ionizing radiation. It acts very fast and predominantly damages nucleic acids, conserving most of the antigenic structures. However, currently used irradiation technologies (mostly gamma-rays and high energy electrons) require large and complex shielding constructions to protect the environment from radioactivity or X-rays generated during the process. This excludes them from direct integration into biological production facilities. Here, low-energy electron irradiation (LEEI) is presented as an alternative inactivation method for pathogens in liquid solutions. LEEI can be used in normal laboratories, including good manufacturing practice (GMP)- or high biosafety level (BSL)-environments, as only minor shielding is necessary. We show that LEEI efficiently inactivates different viruses (influenza A (H3N8), porcine reproductive and respiratory syndrome virus (PRRSV), equine herpesvirus 1 (EHV-1)) and bacteria (Escherichia coli) and maintains their antigenicity. Moreover, LEEI-inactivated influenza A viruses elicit protective immune responses in animals, as analyzed by virus neutralization assays and viral load determination upon challenge. These results have implications for novel ways of developing and manufacturing inactivated vaccines with improved efficacy. PMID:27886076

Pathogen inactivation techniques.

Science.gov (United States)

Pelletier, J P R; Transue, S; Snyder, E L

2006-01-01

of investigation. Clearly, regulatory agencies have a major role to play in the evaluation of these new technologies. This chapter will cover the several types of pathogen-reduction systems, mechanisms of action, the inactivation efficacy for specific types of pathogens, toxicology of the various systems and the published research and clinical trial data supporting their potential usefulness. Due to the nature of the field, pathogen reduction is a work in progress and this review should be considered as a snapshot in time rather than a clear picture of what the future will bring.

Recombinant fusion protein of albumin-retinol binding protein inactivates stellate cells

International Nuclear Information System (INIS)

Choi, Soyoung; Park, Sangeun; Kim, Suhyun; Lim, Chaeseung; Kim, Jungho; Cha, Dae Ryong; Oh, Junseo

2012-01-01

Highlights: ► We designed novel recombinant albumin-RBP fusion proteins. ► Expression of fusion proteins inactivates pancreatic stellate cells (PSCs). ► Fusion proteins are successfully internalized into and inactivate PSCs. ► RBP moiety mediates cell specific uptake of fusion protein. -- Abstract: Quiescent pancreatic- (PSCs) and hepatic- (HSCs) stellate cells store vitamin A (retinol) in lipid droplets via retinol binding protein (RBP) receptor and, when activated by profibrogenic stimuli, they transform into myofibroblast-like cells which play a key role in the fibrogenesis. Despite extensive investigations, there is, however, currently no appropriate therapy available for tissue fibrosis. We previously showed that the expression of albumin, composed of three homologous domains (I–III), inhibits stellate cell activation, which requires its high-affinity fatty acid-binding sites asymmetrically distributed in domain I and III. To attain stellate cell-specific uptake, albumin (domain I/III) was coupled to RBP; RBP-albumin domain III (R-III) and albumin domain I -RBP-albumin III (I-R-III). To assess the biological activity of fusion proteins, cultured PSCs were used. Like wild type albumin, expression of R-III or I-R-III in PSCs after passage 2 (activated PSCs) induced phenotypic reversal from activated to fat-storing cells. On the other hand, R-III and I-R-III, but not albumin, secreted from transfected 293 cells were successfully internalized into and inactivated PSCs. FPLC-purified R-III was found to be internalized into PSCs via caveolae-mediated endocytosis, and its efficient cellular uptake was also observed in HSCs and podocytes among several cell lines tested. Moreover, tissue distribution of intravenously injected R-III was closely similar to that of RBP. Therefore, our data suggest that albumin-RBP fusion protein comprises of stellate cell inactivation-inducing moiety and targeting moiety, which may lead to the development of effective anti

Influenza Vaccination Strategies: Comparing Inactivated and Live Attenuated Influenza Vaccines

Directory of Open Access Journals (Sweden)

Saranya Sridhar

2015-04-01

Full Text Available Influenza is a major respiratory pathogen causing annual outbreaks and occasional pandemics. Influenza vaccination is the major method of prophylaxis. Currently annual influenza vaccination is recommended for groups at high risk of complications from influenza infection such as pregnant women, young children, people with underlying disease and the elderly, along with occupational groups such a healthcare workers and farm workers. There are two main types of vaccines available: the parenteral inactivated influenza vaccine and the intranasal live attenuated influenza vaccine. The inactivated vaccines are licensed from 6 months of age and have been used for more than 50 years with a good safety profile. Inactivated vaccines are standardized according to the presence of the viral major surface glycoprotein hemagglutinin and protection is mediated by the induction of vaccine strain specific antibody responses. In contrast, the live attenuated vaccines are licensed in Europe for children from 2–17 years of age and provide a multifaceted immune response with local and systemic antibody and T cell responses but with no clear correlate of protection. Here we discuss the immunological immune responses elicited by the two vaccines and discuss future work to better define correlates of protection.

X-linked gene expression and X-chromosome inactivation: marsupials, mouse, and man compared.

Science.gov (United States)

VandeBerg, J L; Robinson, E S; Samollow, P B; Johnston, P G

1987-01-01

The existence of paternal X inactivation in Australian and American marsupial species suggests that this feature of X-chromosome dosage compensation is not a recent adaptation, but probably predates the evolutionary separation of the Australian and American marsupial lineages. Although it is theoretically possible that the marsupial system is one of random X inactivation with p greater than 0.99 and q less than 0.01 and dependent on parental source, no instance of random X inactivation (p = q or p not equal to q) has ever been verified in any tissue or cell type of any marsupial species. Therefore, we conclude that the most fundamental difference in X inactivation of marsupials and eutherians is whether the inactive X is the paternal one or is determined at random (with p = q in most but not all cases). The only other unequivocal difference between eutherians and marsupials is that both X chromosomes are active in mice and human oocytes, but not in kangaroo oocytes. Apparently, the inactive X is reactivated at a later meiotic stage or during early embryogenesis in kangaroos. X-chromosome inactivation takes place early in embryogenesis of eutherians and marsupials. Extraembryonic membranes of mice exhibit paternal X inactivation, whereas those of humans seem to exhibit random X inactivation with p greater than q (i.e., preferential paternal X inactivation). In general, extraembryonic membranes of marsupial exhibit paternal X inactivation, but the Gpd locus is active on both X chromosomes in at least some cells of kangaroo yolk sac. It is difficult to draw any general conclusion because of major differences in embryogeny of mice, humans, and marsupials, and uncertainties in interpreting the data from humans. Other differences between marsupials and eutherians in patterns of X-linked gene expression and X-chromosome inactivation seem to be quantitative rather than qualitative. Partial expression of some genes on the inactive X is characteristic of marsupials, with

Reversible Heat-Induced Inactivation of Chimeric β-Glucuronidase in Transgenic Plants1

Science.gov (United States)

Almoguera, Concepción; Rojas, Anabel; Jordano, Juan

2002-01-01

We compared the expression patterns in transgenic tobacco (Nicotiana tabacum) of two chimeric genes: a translational fusion to β-glucuronidase (GUS) and a transcriptional fusion, both with the same promoter and 5′-flanking sequences of Ha hsp17.7 G4, a small heat shock protein (sHSP) gene from sunflower (Helianthus annuus). We found that immediately after heat shock, the induced expression from the two fusions in seedlings was similar, considering chimeric mRNA or GUS protein accumulation. Surprisingly, we discovered that the chimeric GUS protein encoded by the translational fusion was mostly inactive in such conditions. We also found that this inactivation was fully reversible. Thus, after returning to control temperature, the GUS activity was fully recovered without substantial changes in GUS protein accumulation. In contrast, we did not find differences in the in vitro heat inactivation of the respective GUS proteins. Insolubilization of the chimeric GUS protein correlated with its inactivation, as indicated by immunoprecipitation analyses. The inclusion in another chimeric gene of the 21 amino-terminal amino acids from a different sHSP lead to a comparable reversible inactivation. That effect not only illustrates unexpected post-translational problems, but may also point to sequences involved in interactions specific to sHSPs and in vivo heat stress conditions. PMID:12011363

Inactivation of enteroviruses in sewage with ozone

Energy Technology Data Exchange (ETDEWEB)

Ivanova, O.E.; Bogdanov, M.V.; Kazantseva, V.A.; Gabrilevskaia, L.N.; Kodkind, G.K.H.

The study of ozone inactivation of enteroviruses in sewage showed the presence in sewage of suspensions of organic origin and bacterial flora to influence the rate of inactivation. The inactivation rate of poliomyelitis virus in sewage free from organic suspension and bacterial flora was significantly higher than that in sewage containing such suspension and bacterial flora. The inactivation rate of enteroviruses was found not to depend upon the protein and salt composition and pH of sewage or strain appurtenance of viruses. The inactivation rate of enteroviruses directly depended upon the dose of ozone and time of contact with it. Differences in the resistance of different types of poliomyelitis virus, ECHO and Coxsackie viruses to the effect of ozone are likely exist. These differences are manifested within the range of relatively small doses of ozone. E. coli is more resistant to ozone than entero-viruses. The results of laboratory studies were used to choose the regimen of sanitation of urban sewage to be used in technological cycles of industrial enterprises.

Mycobacteria inactivation using Engineered Water Nanostructures (EWNS).

Science.gov (United States)

Pyrgiotakis, Georgios; McDevitt, James; Gao, Ya; Branco, Alan; Eleftheriadou, Mary; Lemos, Bernardo; Nardell, Edward; Demokritou, Philip

2014-08-01

Airborne transmitted pathogens such as Mycobacterium tuberculosis (Mtb) cause serious, often fatal infectious disease with enormous global health implications. Due to their unique cell wall and slow growth, mycobacteria are among the most resilient microbial forms. Herein we evaluate the ability of an emerging, chemical-free, nanotechnology-based method to inactivate M. parafortuitum (Mtb surrogate). This method is based on the transformation of atmospheric water vapor into engineered water nano-structures (EWNS) via electrospray. We demonstrate that the EWNS can interact with and inactivate airborne mycobacteria, reducing their concentration levels significantly. Additionally, EWNS can inactivate M. parafortuitum on surfaces eight times faster than the control. The mechanism of mycobacteria inactivation was also investigated in this study. It was demonstrated that the EWNS effectively deliver the reactive oxygen species, encapsulated during the electrospray process, to the bacteria oxidizing their cell membrane resulting into inactivation. Overall, this is a method with the potential to become an effective intervention technology in the battle against airborne infections. This study demonstrates the feasibility of mycobacterium inactivation in airborne form or on contact surfaces using electrospray activated water nano-structures. Given that the method is free of toxic chemicals, this might become an important tool in the prevention of mycobacterial infections, which are notoriously hard to treat. Copyright © 2014 Elsevier Inc. All rights reserved.

Carbapenem inactivation: a very affordable and highly specific method for phenotypic detection of carbapenemase-producing Pseudomonas aeruginosa isolates compared with other methods.

Science.gov (United States)

Akhi, Mohammad Taghi; Khalili, Younes; Ghotaslou, Reza; Kafil, Hossein Samadi; Yousefi, Saber; Nagili, Behroz; Goli, Hamid Reza

2017-06-01

This investigation was undertaken to compare phenotypic and molecular methods for detection of carbapenemase-producing Pseudomonas aeruginosa. A total of 245 non-duplicated isolates of P. aeruginosa were collected from hospitalized patients. Disc diffusion method was used to identify carbapenem-resistant bacteria. Three phenotypic methods, including Modified Hodge Test (MHT), Modified Carba NP (MCNP) test and Carbapenem Inactivation Method (CIM) were used for investigation of carbapenemase production. In addition, polymerase chain reaction (PCR) was used to detect carbapenemase encoding genes. Of 245 P. aeruginosa isolates investigated, 121 isolates were carbapenem-resistant. Among carbapenem-resistant isolates, 40, 39 and 35 isolates exhibited positive results using MHT, MCNP test and CIM, respectively. PCR indicated the presence of carbapenemase genes in 35 of carbapenem-resistant isolates. MHT showed low sensitivity and specificity for carbapenemase detection among P. aeruginosa isolates in comparison to PCR. CIM was most affordable and highly specific than MCNP test compared with the molecular method.

Inactivated recombinant plant virus protects dogs from a lethal challenge with canine parvovirus.

Science.gov (United States)

Langeveld, J P; Brennan, F R; Martínez-Torrecuadrada, J L; Jones, T D; Boshuizen, R S; Vela, C; Casal, J I; Kamstrup, S; Dalsgaard, K; Meloen, R H; Bendig, M M; Hamilton, W D

2001-06-14

A vaccine based upon a recombinant plant virus (CPMV-PARVO1), displaying a peptide derived from the VP2 capsid protein of canine parvovirus (CPV), has previously been described. To date, studies with the vaccine have utilized viable plant chimaeric particles (CVPs). In this study, CPMV-PARVO1 was inactivated by UV treatment to remove the possibility of replication of the recombinant plant virus in a plant host after manufacture of the vaccine. We show that the inactivated CVP is able to protect dogs from a lethal challenge with CPV following parenteral immunization with the vaccine. Dogs immunized with the inactivated CPMV-PARVO1 in adjuvant displayed no clinical signs of disease and shedding of CPV in faeces was limited following CPV challenge. All immunized dogs elicited high titres of peptide-specific antibody, which neutralized CPV in vitro. Levels of protection, virus shedding and VP2-specific antibody were comparable to those seen in dogs immunized with the same VP2- peptide coupled to keyhole limpet hemocyanin (KLH). Since plant virus-derived vaccines have the potential for cost-effective manufacture and are not known to replicate in mammalian cells, they represent a viable alternative to current replicating vaccine vectors for development of both human and veterinary vaccines.

Kinetics of recB-dependent repair: Relationship to post-UV inactivation of the prophage

International Nuclear Information System (INIS)

Trgovcevic, Z.; Petranovic, D.; Salaj-Smic, E.; Petranovic, M.

1987-01-01

By making use of the temperature-sensitive mutant recB270, we showed that the RecBCD enzyme is needed for repair between 1 and 4 h after UV exposure. recB-dependent prophage inactivation takes place in all dying cells during the same period of time. The kinetics of decrease in the yield of recombinants in phage-prophage crosses resemble those of prophage inactivation in UV-irradiated bacteria. This indicates that recombination processes (including site-specific recombination required for prophage excision) are blocked in cells destined to die. On the basis of our results, we suggest that a large fraction of damaged cells is rescued by the RecA-RecBCD recombination pathway. If repair is unsuccessful, RecA-RecBCD recombinaton intermediates persist in the irradiated cells leading to prophage inactivation. 27 refs.; 4 figs

Thermal Inactivation of avian influenza virus in poultry litter as a method to decontaminate poultry houses.

Science.gov (United States)

Stephens, Christopher B; Spackman, Erica

2017-09-15

Removal of contaminated material from a poultry house during recovery from an avian influenza virus (AIV) outbreak is costly and labor intensive. Because AIV is not environmentally stable, heating poultry houses may provide an alternative disinfection method. The objective was to determine the time necessary to inactivate AIV in poultry litter at temperatures achievable in a poultry house. Low pathogenic (LP) AIV inactivation was evaluated between 10.0°-48.9°C, at ∼5.5°C intervals and highly pathogenic (HP) AIV inactivation was evaluated between 10.0°-43.3°C, at ∼11°C intervals. Samples were collected at numerous time points for each temperature. Virus isolation in embryonating chicken eggs was conducted to determine if viable virus was present. Each sample was also tested by real-time RT-PCR. Low pathogenicity AIV was inactivated at 1day at 26.7°C or above. At 10.0, 15.6 and 21.1°C, inactivation times increased to 2-5days. Highly pathogenic AIV followed a similar trend; the virus was inactivated after 1day at 43.3°C and 32.2°C, and required 2 and 5days for inactivation at 21.1°C and 10.0°C respectively. While low pathogenicity AIV appeared to be inactivated at a lower temperature than high pathogenicity AIV, this was not due to any difference in the strains, but due to fewer temperature points being evaluated for high pathogenicity. Endpoints for detection by real-time RT-PCR were not found even weeks after the virus was inactivated. This provides a guideline for the time required, at specific temperatures to inactivate AIV in poultry litter and likely on surfaces within the house. Heat treatment will provide an added level of safety to personnel and against further spread by eliminating infectious virus prior to cleaning a house. Published by Elsevier B.V.

EVALUATION OF REACTOGENICITY, SAFETY AND IMMUNOGENICITY OF INACTIVATED MONOVALENT VACCINE IN CHILDREN

Directory of Open Access Journals (Sweden)

A.N. Mironov

2010-01-01

Full Text Available NPO «Microgen» developed vaccine «PANDEFLU» — influenza inactivated subunit adsorbed monovalent vaccine, strain A/California/7/2009 (H1N1, for specific prophylaxis of pandemic influenza in different age groups of citizens. Reactogenicity, safety and immunogenicity were analyzed in a study of volunteers 18–60 years old. The article presents results of administration of vaccine «PANDEFLU» in children. The study performed in two clinical centers proves good tolerability, reactogenicity, safety and high immunogenicity of this vaccine.Key words: children, influenza, influenza virus А/H1N1, inactivated influenza vaccine, reactogenicity, safety, immunogenicity.(Voprosy sovremennoi pediatrii — Current Pediatrics. – 2010;9(4:106-109

Structure of suicide-inactivated β-hydroxydecanoyl-thioester dehydrase

International Nuclear Information System (INIS)

Schwab, J.M.; Ho, C.K.; Li, W.B.; Townsend, C.A.; Salituro, G.M.

1986-01-01

β-Hydroxydecanoylthioester dehydrase, the key enzyme in biosynthesis of unsaturated fatty acids under anaerobic conditions, equilibrates thioesters of (R)-3-hydroxydecanoic acid, E-2-decenoic acid, and Z-3-decenoic acid. Dehydrase is irreversibly inactivated by the N-acetylcysteamine thioester of 3-decynoic acid (3-decynoyl-NAC), via dehydrase-catalyzed isomerization to 2,3-decadienoyl-NAC. To probe the relationship between normal catalysis and suicide inactivation, the structure of the inactivated enzyme has been studied. 3-[2- 13 C]Decynoyl-NAC was synthesized and incubated with dehydrase. 13 C NMR showed that attack of 2,3-decadienoyl-NAC by the active site histidine gives 3-histidinyl-3-decenoyl-NAC, which slowly rearranges to the more stable Δ 2 isomer. Model histidine-allene adducts have been made and characterized. Analysis of NMR data show that the C=C configuration of the decenoyl moiety of enzyme-bound inactivator is E. The suggestion that the mechanism of dehydrase inactivation parallels its normal mechanism of action is supported these findings

Modelling and application of the inactivation of microorganism

International Nuclear Information System (INIS)

Oğuzhan, P.; Yangılar, F.

2013-01-01

Prevention of consuming contaminated food with toxic microorganisms causing infections and consideration of food protection and new microbial inactivation methods are obligatory situations. Food microbiology is mainly related with unwanted microorganisms spoiling foods during processing and transporting stages and causing diseases. Determination of pathogen microorganisms is important for human health to define and prevent dangers and elongate shelf life. Inactivation of pathogen microorganisms can provide food security and reduce nutrient losses. Microbial inactivation which is using methods of food protection such as food safety and fresh. With this aim, various methods are used such as classical thermal processes (pasteurisation, sterilisation), pressured electrical field (PEF), ionised radiation, high pressure, ultrasonic waves and plasma sterilisation. Microbial inactivation modelling is a secure and effective method in food production. A new microbiological application can give useful results for risk assessment in food, inactivation of microorganisms and improvement of shelf life. Application and control methods should be developed and supported by scientific research and industrial applications

Immunogenicity of an electron beam inactivated Rhodococcus equi vaccine in neonatal foals.

Directory of Open Access Journals (Sweden)

Angela I Bordin

Full Text Available Rhodococcus equi is an important pathogen of foals that causes severe pneumonia. To date, there is no licensed vaccine effective against R. equi pneumonia of foals. The objectives of our study were to develop an electron beam (eBeam inactivated vaccine against R. equi and evaluate its immunogenicity. A dose of eBeam irradiation that inactivated replication of R. equi while maintaining outer cell wall integrity was identified. Enteral administration of eBeam inactivated R. equi increased interferon-γ production by peripheral blood mononuclear cells in response to stimulation with virulent R. equi and generated naso-pharyngeal R. equi-specific IgA in newborn foals. Our results indicate that eBeam irradiated R. equi administered enterally produce cell-mediated and upper respiratory mucosal immune responses, in the face of passively transferred maternal antibodies, similar to those produced in response to enteral administration of live organisms (a strategy which previously has been documented to protect foals against intrabronchial infection with virulent R. equi. No evidence of adverse effects was noted among vaccinated foals.

SMARCB1/INI1 inactivation in renal medullary carcinoma.

Science.gov (United States)

Calderaro, Julien; Moroch, Julien; Pierron, Gaelle; Pedeutour, Florence; Grison, Camille; Maillé, Pascale; Soyeux, Pascale; de la Taille, Alexandre; Couturier, Jérome; Vieillefond, Annick; Rousselet, Marie Christine; Delattre, Olivier; Allory, Yves

2012-09-01

Renal medullary carcinoma (RMC), a rare and highly aggressive tumour which occurs in patients with sickle-cell disease, shares many clinicopathological features with collecting duct carcinoma (CDC). The molecular mechanisms underlying RMC and CDC are mainly unknown, and there is ongoing debate about their status as distinct entities. Loss of expression of SMARCB1/INI1, a chromatin remodelling regulator and repressor of cyclin D1 transcription, has been reported recently in RMC. The aim of our study was to investigate if such loss of expression is specific for RMC. SMARCB1/INI1 genetic alterations and cyclin D1 expression were also studied. Using immunochemistry, neoplastic cells showed complete loss of SMARCB1/INI1 expression in all six cases of RMC but in only one of 22 cases of CDC. In two RMC cases investigated, comparative genomic hybridization demonstrated complete loss of one SMARCB1/INI1 allele, with no other genomic imbalances, and no mutations were found on the remaining allele. Cyclin D1 was expressed in all RMCs, suggesting that SMARCB1/INI1 inactivation may result in increased cyclin D1 transcription. The specific SMARCB1/INI1 inactivation observed in RMCs suggests that RMC and CDC are different entities. © 2012 Blackwell Publishing Ltd.

Human active X-specific DNA methylation events showing stability across time and tissues

Science.gov (United States)

Joo, Jihoon Eric; Novakovic, Boris; Cruickshank, Mark; Doyle, Lex W; Craig, Jeffrey M; Saffery, Richard

2014-01-01

The phenomenon of X chromosome inactivation in female mammals is well characterised and remains the archetypal example of dosage compensation via monoallelic expression. The temporal series of events that culminates in inactive X-specific gene silencing by DNA methylation has revealed a ‘patchwork' of gene inactivation along the chromosome, with approximately 15% of genes escaping. Such genes are therefore potentially subject to sex-specific imbalance between males and females. Aside from XIST, the non-coding RNA on the X chromosome destined to be inactivated, very little is known about the extent of loci that may be selectively silenced on the active X chromosome (Xa). Using longitudinal array-based DNA methylation profiling of two human tissues, we have identified specific and widespread active X-specific DNA methylation showing stability over time and across tissues of disparate origin. Our panel of X-chromosome loci subject to methylation on Xa reflects a potentially novel mechanism for controlling female-specific X inactivation and sex-specific dimorphisms in humans. Further work is needed to investigate these phenomena. PMID:24713664

HPV-16 L1 genes with inactivated negative RNA elements induce potent immune responses

International Nuclear Information System (INIS)

Rollman, Erik; Arnheim, Lisen; Collier, Brian; Oeberg, Daniel; Hall, Haakan; Klingstroem, Jonas; Dillner, Joakim; Pastrana, Diana V.; Buck, Chris B.; Hinkula, Jorma; Wahren, Britta; Schwartz, Stefan

2004-01-01

Introduction of point mutations in the 5' end of the human papillomavirus type 16 (HPV-16) L1 gene specifically inactivates negative regulatory RNA processing elements. DNA vaccination of C57Bl/6 mice with the mutated L1 gene resulted in improved immunogenicity for both neutralizing antibodies as well as for broad cellular immune responses. Previous reports on the activation of L1 by codon optimization may be explained by inactivation of the regulatory RNA elements. The modified HPV-16 L1 DNA that induced anti-HPV-16 immunity may be seen as a complementary approach to protein subunit immunization against papillomavirus

Recombinant fusion protein of albumin-retinol binding protein inactivates stellate cells

Energy Technology Data Exchange (ETDEWEB)

Choi, Soyoung; Park, Sangeun; Kim, Suhyun [Laboratory of Cellular Oncology, Korea University Graduate School of Medicine, Ansan, Gyeonggi do 425-707 (Korea, Republic of); Lim, Chaeseung [Department of Laboratory Medicine, Korea University Guro Hospital, Seoul 152-703 (Korea, Republic of); Kim, Jungho [Department of Life Science, Sogang University, Seoul 121-742 (Korea, Republic of); Cha, Dae Ryong [Department of Internal Medicine, Korea University Ansan Hospital, Ansan, Gyeonggi do 425-020 (Korea, Republic of); Oh, Junseo, E-mail: ohjs@korea.ac.kr [Laboratory of Cellular Oncology, Korea University Graduate School of Medicine, Ansan, Gyeonggi do 425-707 (Korea, Republic of)

2012-02-03

Highlights: Black-Right-Pointing-Pointer We designed novel recombinant albumin-RBP fusion proteins. Black-Right-Pointing-Pointer Expression of fusion proteins inactivates pancreatic stellate cells (PSCs). Black-Right-Pointing-Pointer Fusion proteins are successfully internalized into and inactivate PSCs. Black-Right-Pointing-Pointer RBP moiety mediates cell specific uptake of fusion protein. -- Abstract: Quiescent pancreatic- (PSCs) and hepatic- (HSCs) stellate cells store vitamin A (retinol) in lipid droplets via retinol binding protein (RBP) receptor and, when activated by profibrogenic stimuli, they transform into myofibroblast-like cells which play a key role in the fibrogenesis. Despite extensive investigations, there is, however, currently no appropriate therapy available for tissue fibrosis. We previously showed that the expression of albumin, composed of three homologous domains (I-III), inhibits stellate cell activation, which requires its high-affinity fatty acid-binding sites asymmetrically distributed in domain I and III. To attain stellate cell-specific uptake, albumin (domain I/III) was coupled to RBP; RBP-albumin{sup domain} {sup III} (R-III) and albumin{sup domain} {sup I}-RBP-albumin{sup III} (I-R-III). To assess the biological activity of fusion proteins, cultured PSCs were used. Like wild type albumin, expression of R-III or I-R-III in PSCs after passage 2 (activated PSCs) induced phenotypic reversal from activated to fat-storing cells. On the other hand, R-III and I-R-III, but not albumin, secreted from transfected 293 cells were successfully internalized into and inactivated PSCs. FPLC-purified R-III was found to be internalized into PSCs via caveolae-mediated endocytosis, and its efficient cellular uptake was also observed in HSCs and podocytes among several cell lines tested. Moreover, tissue distribution of intravenously injected R-III was closely similar to that of RBP. Therefore, our data suggest that albumin-RBP fusion protein comprises

Removal of detergents from SDS-inactivated dextransucrase

International Nuclear Information System (INIS)

Husman, D.W.; Mayer, R.M.

1986-01-01

Dextransucrase, which is rapidly inactivated by SDS, can be reactivated upon the addition of Triton X-100. Purification of the enzyme, in good yield and homogeneity, has been achieved by chromatography in the presence of SDS. The purified enzyme can be reactivated with Triton, but has large amounts of detergents. It was important to develop procedures for their removal. Density gradient centrifugation of SDS-inactivated or Triton-reactivated enzyme, treatment with Extracti-Gel D (Pierce) or chromatography on hydroxyl apatite (HA), have been examined for their effectiveness in providing detergent-free enzyme in good yield. Ultracentrifugation of SDS-inactivated protein provided limited recovery of active enzyme, but suggested that reactivation could be achieved by the simple removal of the detergent. While similar behavior was observed when the enzyme was eluted from Extracti-Gel, it was also shown that the limited recovery was a result of irreversible inactivation of the enzyme. Recovery could be improved if the enzyme was collected in solutions containing Triton, which has been reported to be a stabilizer. Chromatography of SDS-inactivated enzyme on HA also yielded active enzyme. Good recovery was obtained when Triton-reactivated enzyme was employed in these studies. The degree of detergent removal was determined by utilizing radiolabelled SDS and Triton X-100

Luciferase inactivation in the luminous marine bacterium Vibrio harveyi.

Science.gov (United States)

Reeve, C A; Baldwin, T O

1981-06-01

Luciferase was rapidly inactivated in stationary-phase cultures of the wild type of the luminous marine bacterium Vibrio harveyi, but was stable in stationary-phase cultures of mutants of V. harveyi that are nonluminous without exogenous aldehyde, termed the aldehyde-deficient mutants. The inactivation in the wild type was halted by cell lysis and was slowed or stopped by O2 deprivation or by addition of KCN and NaF or of chloramphenicol. If KCN and NaF or chloramphenicol were added to a culture before the onset of luciferase inactivation, then luciferase inactivation did not occur. However, if these inhibitors were added after the onset of luciferase inactivation, then luciferase inactivation continued for about 2 to 3 h before the inactivation process stopped. The onset of luciferase inactivation in early stationary-phase cultures of wild-type cell coincided with a slight drop in the intracellular adenosine 5'-triphosphate (ATP) level from a relatively constant log-phase value of 20 pmol of ATP per microgram of soluble cell protein. Addition of KCN and NaF to a culture shortly after this drop in ATP caused a rapid decrease in the ATP level to about 4 pmol of ATP per microgram whereas chloramphenicol added at this same time caused a transient increase in ATP level to about 25 pmol/microgram. The aldehyde-deficient mutant (M17) showed a relatively constant log-phase ATP level identical with that of the wild-type cells, but rather than decreasing in early stationary phase, the ATP level increased to a value twice that in log-phase cells. We suggest that the inactivation of luciferase is dependent on the synthesis of some factor which is produced during stationary phase and is itself unstable, and whose synthesis is blocked by chloramphenicol or cyanide plus fluoride.

Comparison of two different methods for inactivation of viruses in serum

DEFF Research Database (Denmark)

Preuss, T.; Kamstrup, Søren; Kyvsgaard, N.C.

1997-01-01

enterovirus (PEV) was inactivated within 3 h, The inactivation with electron-beam irradiation resulted in almost linear curves in a semilogarithmic plot of virus titer versus irradiation dose, reflecting a first-order inactivation, The rate of inactivation was almost twice as fast in the liquid samples...

Regional inactivations of primate ventral prefrontal cortex reveal two distinct mechanisms underlying negative bias in decision making.

Science.gov (United States)

Clarke, Hannah F; Horst, Nicole K; Roberts, Angela C

2015-03-31

Dysregulation of the orbitofrontal and ventrolateral prefrontal cortices is implicated in anxiety and mood disorders, but the specific contributions of each region are unknown, including how they gate the impact of threat on decision making. To address this, the effects of GABAergic inactivation of these regions were studied in marmoset monkeys performing an instrumental approach-avoidance decision-making task that is sensitive to changes in anxiety. Inactivation of either region induced a negative bias away from punishment that could be ameliorated with anxiolytic treatment. However, whereas the effects of ventrolateral prefrontal cortex inactivation on punishment avoidance were seen immediately, those of orbitofrontal cortex inactivation were delayed and their expression was dependent upon an amygdala-anterior hippocampal circuit. We propose that these negative biases result from deficits in attentional control and punishment prediction, respectively, and that they provide the basis for understanding how distinct regional prefrontal dysregulation contributes to the heterogeneity of anxiety disorders with implications for cognitive-behavioral treatment strategies.

Leukotriene B4 omega-hydroxylase in human polymorphonuclear leukocytes. Suicidal inactivation by acetylenic fatty acids.

Science.gov (United States)

Shak, S; Reich, N O; Goldstein, I M; Ortiz de Montellano, P R

1985-10-25

Human polymorphonuclear leukocytes (PMN) not only generate and respond to leukotriene B4 (LTB4), but also catabolize this mediator of inflammation rapidly and specifically by omega-oxidation (probably due to the action of a cytochrome P-450 enzyme). To develop pharmacologically useful inhibitors of the LTB4 omega-hydroxylase in human PMN, we devised a general scheme for synthesizing terminal acetylenic fatty acids based on the "acetylenic zipper" reaction. We found that the LTB4 omega-hydroxylase in intact PMN and in PMN sonicates is inactivated in a concentration-dependent fashion by terminal acetylenic analogues of lauric, palmitic, and stearic acids (i.e. 11-dodecynoic, 15-hexadecynoic, and 17-octadecynoic acids). Consistent with a suicidal process, inactivation of the LTB4 omega-hydroxylase requires molecular oxygen and NADPH, is time-dependent, and follows pseudo-first-order kinetics. Inactivation of the omega-hydroxylase by acetylenic fatty acids also is dependent on the terminal acetylenic moiety and the carbon chain length. Saturated fatty acids lacking a terminal acetylenic moiety do not inactivate the omega-hydroxylase. In addition, the two long-chain (C16, C18) acetylenic fatty acids inactivate the omega-hydroxylase at much lower concentrations (less than 5.0 microM) than those required for inactivation by the short-chain (C12) terminal acetylenic fatty acid (100 microM). Potent suicidal inhibitors of the LTB4 omega-hydroxylase in human PMN will help elucidate the roles played by LTB4 and its omega-oxidation products in regulating PMN function and in mediating inflammation.

Inactivation of Lassa, Marburg, and Ebola viruses by gamma irradiation

International Nuclear Information System (INIS)

Elliott, L.H.; McCormick, J.B.; Johnson, K.M.

1982-01-01

Because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. The infectivity of Lassa, Marburg, and Ebola viruses was inactivated without altering the immunological activity after radiation with 60 CO gamma rays. At 4 degrees C, Lassa virus was the most difficult to inactivate with a rate of 5.3 X 10(-6) log 50% tissue culture infective dose per rad of 60 CO radiation, as compared with 6.8 X 10(-6) log 50% tissue culture infective dose per rad for Ebola virus and 8.4 X 10(-6) log 50% tissue culture infective dose per rad for Marburg virus. Experimental inactivation curves, as well as curves giving the total radiation needed to inactivate a given concentration of any of the three viruses, are presented. The authors found this method of inactivation to be superior to UV light or beta-propiolactone inactivation and now routinely use it for preparation of material for protein-chemistry studies or for preparation of immunological reagents

Inactivation of Lassa, Marburg, and Ebola viruses by gamma irradiation

International Nuclear Information System (INIS)

Elliott, L.H.; McCormick, J.B.; Johnson, K.M.

1982-01-01

Because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. The infectivity of Lassa, Marburg, and Ebola viruses was inactivated without altering the immunological activity after radiation with 60 Co gamma rays. At 4 degrees C, Lassa virus was the most difficult to inactivate with a rate of 5.3 X 10(-6) log 50% tissue culture infective dose per rad of 60 Co radiation, as compared with 6.8 X 10(-6) log 50% tissue culture infective dose per rad for Ebola virus and 8.4 X 10(-6) log 50% tissue culture infective dose per rad for Marburg virus. Experimental inactivation curves, as well as curves giving the total radiation needed to inactivate a given concentration of any of the three viruses, are presented. We found this method of inactivation to be superior to UV light or beta-propiolactone inactivation and now routinely use it for preparation of material for protein-chemistry studies or for preparation of immunological reagents

Site-specific, insertional inactivation of incA in Chlamydia trachomatis using a group II intron.

Science.gov (United States)

Johnson, Cayla M; Fisher, Derek J

2013-01-01

Chlamydia trachomatis is an obligate, intracellular bacterial pathogen that has until more recently remained recalcitrant to genetic manipulation. However, the field still remains hindered by the absence of tools to create selectable, targeted chromosomal mutations. Previous work with mobile group II introns demonstrated that they can be retargeted by altering DNA sequences within the intron's substrate recognition region to create site-specific gene insertions. This platform (marketed as TargeTron™, Sigma) has been successfully employed in a variety of bacteria. We subsequently modified TargeTron™ for use in C. trachomatis and as proof of principle used our system to insertionally inactivate incA, a chromosomal gene encoding a protein required for homotypic fusion of chlamydial inclusions. C. trachomatis incA::GII(bla) mutants were selected with ampicillin and plaque purified clones were then isolated for genotypic and phenotypic analysis. PCR, Southern blotting, and DNA sequencing verified proper GII(bla) insertion, while continuous passaging in the absence of selection demonstrated that the insertion was stable. As seen with naturally occurring IncA(-) mutants, light and immunofluorescence microscopy confirmed the presence of non-fusogenic inclusions in cells infected with the incA::GII(bla) mutants at a multiplicity of infection greater than one. Lack of IncA production by mutant clones was further confirmed by Western blotting. Ultimately, the ease of retargeting the intron, ability to select for mutants, and intron stability in the absence of selection makes this method a powerful addition to the growing chlamydial molecular toolbox.

Photodynamic inactivation of foodborne bacteria by eosin Y.

Science.gov (United States)

Bonin, E; Dos Santos, A R; Fiori da Silva, A; Ribeiro, L H; Favero, M E; Campanerut-Sá, P A Z; de Freitas, C F; Caetano, W; Hioka, N; Mikcha, J M G

2018-03-25

The aim of this study was evaluate the effect of photodynamic inactivation mediated by eosin Y in Salmonella enterica serotype Typhimurium ATCC 14028, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and Bacillus cereus ATCC 11778. Bacteria (10 7 CFU per ml) were incubated with eosin Y at concentrations ranging from 0·1 to 10 μmol l -1 , irradiated by green LED (λ max 490-570 nm) for 5, 10 and 15 min and the cellular viability was determined. Pseudomonas aeruginosa was completely inactivated when treated with 10 μmol l -1 eosin Y for 10 min. Treatments reduced B. cereus and Salm. Typhimurium counts to 2·7 log CFU per ml and 1·7 log CFU per ml, respectively. Escherichia coli counts were slightly reduced. Staphylococcus aureus presented the highest sensitivity, being completely inactivated by eosin Y at 5 μmol l -1 and 5 min of illumination. The reduction of cellular viability of photoinactivated Staph. aureus was also demonstrated by flow cytometry and morphological changes were observed by scanning electron microscopy. Eosin Y in combination with LED produced bacterial inactivation, being a potential candidate for photodynamic inactivation. This study evidenced the efficacy of photodynamic inactivation as a novel and promising alternative to bacterial control. © 2018 The Society for Applied Microbiology.

Inactivation of Mycobacterium avium with free chlorine.

Science.gov (United States)

Luh, Jeanne; Mariñas, Benito J

2007-07-15

The inactivation kinetics of Mycobacterium avium with free chlorine was characterized by two stages: an initial phase at a relatively fast rate followed by a slower second stage of pseudo first-order kinetics. The inactivation rate of each stage was approximately the same for all experiments performed at a certain condition of pH and temperature; however, variability was observed for the disinfectant exposure at which the transition between the two stages occurred. This variability was not a function of the initial disinfectant concentration, the initial bacterial density, or the bacterial stock. However, the transition to the second stage varied more significantly at high temperatures (30 degrees C), while lower variability was observed at lower temperatures (5 and 20 degrees C). Experiments conducted at pH values in the range of 6-9 revealed that the inactivation of M. avium was primarily due to hypochlorous acid, with little contribution from hypochlorite ion within this pH range. The inactivation kinetics was represented with a two-population model. The activation energies for the resulting pseudo first-order rate constants for the populations with fast and slow kinetics were 100.3 and 96.5 kJ/mol, respectively. The magnitude of these values suggested that for waters of relatively high pH and low temperatures, little inactivation of M. avium would be achieved within treatment plants, providing a seeding source for distribution systems.

Radiation inactivation of multimeric enzymes: application to subunit interactions of adenylate cyclase

International Nuclear Information System (INIS)

Verkman, A.S.; Skorecki, K.L.; Ausiello, D.A.

1986-01-01

Radiation inactivation has been applied extensively to determine the molecular weight of soluble enzyme and receptor systems from the slope of a linear ln (activity) vs. dose curve. Complex nonlinear inactivation curves are predicted for multimeric enzyme systems, composed of distinct subunits in equilibrium with multimeric complexes. For the system A1 + A2----A1A2, with an active A1A2 complex (associative model), the ln (activity) vs. dose curve is linear for high dissociation constant, K. If a monomer, A1, has all the enzyme activity (dissociative model), the ln (activity) vs. dose curve has an activation hump at low radiation dose if the inactive subunit, A2, has a higher molecular weight than A1 and has upward concavity when A2 is smaller than A1. In general, a radiation inactivation model for a multistep mechanism for enzyme activation fulfills the characteristics of an associative or dissociative model if the reaction step forming active enzyme is an associative or dissociative reaction. Target theory gives the molecular weight of the active enzyme subunit or complex from the limiting slope of the ln (activity) vs. dose curve at high radiation dose. If energy transfer occurs among subunits in the multimer, the ln (activity) vs. dose curve is linear for a single active component and is concave upward for two or more active components. The use of radiation inactivation as a method to determine enzyme size and multimeric subunit assembly is discussed with specific application to the hormone-sensitive adenylate cyclase system. It is shown that the complex inactivation curves presented in the accompanying paper can be used select the best mechanism out of a series of seven proposed mechanisms for the activation of adenylate cyclase by hormone

Inactivation of viruses in municipal effluent by chlorine.

OpenAIRE

Hajenian, H. G.; Butler, M.

1980-01-01

The influence of pH and temperature on the efficiency of chlorine inactivation of two unrelated picornaviruses in a typical urban wastewater effluent was examined. Temperature, unlike pH, had relatively little effect on the rate of inactivation. The pH effect was complex and the two viruses differed. The f2 coliphage was more sensitive to chlorine at low pH, but at all values there was a threshold above which additional chlorine resulted in very rapid inactivation. The amount of chlorine requ...

Modified Carbapenem Inactivation Method for Phenotypic Detection of Carbapenemase Production among Enterobacteriaceae.

Science.gov (United States)

Pierce, Virginia M; Simner, Patricia J; Lonsway, David R; Roe-Carpenter, Darcie E; Johnson, J Kristie; Brasso, William B; Bobenchik, April M; Lockett, Zabrina C; Charnot-Katsikas, Angella; Ferraro, Mary Jane; Thomson, Richard B; Jenkins, Stephen G; Limbago, Brandi M; Das, Sanchita

2017-08-01

The ability of clinical microbiology laboratories to reliably detect carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) is an important element of the effort to prevent and contain the spread of these pathogens and an integral part of antimicrobial stewardship. All existing methods have limitations. A new, straightforward, inexpensive, and specific phenotypic method for the detection of carbapenemase production, the carbapenem inactivation method (CIM), was recently described. Here we describe a two-stage evaluation of a modified carbapenem inactivation method (mCIM), in which tryptic soy broth was substituted for water during the inactivation step and the length of this incubation was extended. A validation study was performed in a single clinical laboratory to determine the accuracy of the mCIM, followed by a nine-laboratory study to verify the reproducibility of these results and define the zone size cutoff that best discriminated between CP-CRE and members of the family Enterobacteriaceae that do not produce carbapenemases. Bacterial isolates previously characterized through whole-genome sequencing or targeted PCR as to the presence or absence of carbapenemase genes were tested for carbapenemase production using the mCIM; isolates with Ambler class A, B, and D carbapenemases, non-CP-CRE isolates, and carbapenem-susceptible isolates were included. The sensitivity of the mCIM observed in the validation study was 99% (95% confidence interval [95% CI], 93% to 100%), and the specificity was 100% (95% CI, 82% to 100%). In the second stage of the study, the range of sensitivities observed across nine laboratories was 93% to 100%, with a mean of 97%; the range of specificities was 97% to 100%, with a mean of 99%. The mCIM was easy to perform and interpret for Enterobacteriaceae , with results in less than 24 h and excellent reproducibility across laboratories. Copyright © 2017 American Society for Microbiology.

Physical inactivation and stabilization of sludges

International Nuclear Information System (INIS)

Alexandre, D.

1979-07-01

High temperature conditioning of sludge is a stabilization process that insures sterilization. Both thermal pasteurization and irradiation are inactivation processes. Viruses and parasites are inactivated at 70-80 0 C. Total bacterial destruction requires higher temperatures and/or detention time. Radio sensitivity of pathogens and pertinent treatment parameters are examined. If sludge is to be land disposed, disinfection requires irradiation doses ranging 500 Krad; if cattle feeding is considered, the required dose is 1 Mrad

Inactivation of complement by Loxosceles reclusa spider venom.

Science.gov (United States)

Gebel, H M; Finke, J H; Elgert, K D; Cambell, B J; Barrett, J T

1979-07-01

Zymosan depletion of serum complement in guinea pigs rendered them highly resistant to lesion by Loxosceles reclusa spider venom. Guinea pigs deficient in C4 of the complement system are as sensitive to the venom as normal guinea pigs. The injection of 35 micrograms of whole recluse venom intradermally into guinea pigs lowered their complement level by 35.7%. Brown recluse spider venom in concentrations as slight as 0.02 micrograms protein/ml can totally inactivate one CH50 of guinea pig complement in vitro. Bee, scorpion, and other spider venoms had no influence on the hemolytic titer of complement. Fractionation of recluse spider venom by Sephadex G-200 filtration separated the complement-inactivating property of the venom into three major regions which could be distinguished on the basis of heat stability as well as size. None was neutralized by antivenom. Polyacrylamide gel electrophoresis of venom resolved the complement inactivators into five fractions. Complement inactivated by whole venom or the Sephadex fractions could be restored to hemolytic activity by supplements of fresh serum but not by heat-inactivated serum, pure C3, pure C5, or C3 and C5 in combination.

Randomized Trials Comparing Inactivated Vaccine after Medium- or High-titer Measles Vaccine with Standard Titer Measles Vaccine after Inactivated Vaccine

DEFF Research Database (Denmark)

Aaby, Peter; Ravn, Henrik; Benn, Christine S.

2016-01-01

Background: Observational studies have suggested that girls have higher mortality if their most recent immunization is an inactivated vaccine rather than a live vaccine. We therefore reanalyzed 5 randomized trials of early measles vaccine (MV) in which it was possible to compare an inactivated va...

Germination and Inactivation of Alicyclobacillus acidoterrestris Spores Induced by Moderate Hydrostatic Pressure.

Science.gov (United States)

Sokołowska, Barbara; Skapska, Sylwia; Fonberg-Broczek, Monika; Niezgoda, Jolanta; Porebska, Izabela; Dekowska, Agnieszka; Rzoska, Sylwester J

2015-01-01

Given the importance of spoilage caused by Alicyclobacillus acidoterrestris for the fruit juice industry, the objective of this work was to study the germination and inactivation of A. acidoterrestris spores induced by moderate hydrostatic pressure. Hydrostatic pressure treatment can induce the germination and inactivation of A. acidoterrestris spores. At low pH, spore germination of up to 3.59-3.75 log and inactivation of 1.85-2.04 log was observed in a low pressure window (200-300 MPa) applied at 50 degrees C for 20 min. Neutral pH suppressed inactivation, the number of spores inactivated at pH 7.0 was only 0.24-1.06 log. The pressurization temperature significantly affected spore germination and inactivation. The degree of germination in apple juice after pressurization for 30 min with 200 MPa at 20 degrees C was 2.04 log, with only 0.61 log of spores being inactivated, while at 70 degrees C spore germination was 5.94 log and inactivation 4.72 log. This temperature strongly stimulated germination and inactivation under higher (500 MPa) than lower (200 MPa) pressure. When the oscillatory mode was used, the degree of germination and inactivation was slightly higher than at continuous mode. The degree of germination and inactivation was inversely proportional to the soluble solids content and was lowest in concentrated apple juice.

Inactivation of human and simian rotaviruses by ozone

Energy Technology Data Exchange (ETDEWEB)

Vaughn, J.M.; Chen, Y.S.; Lindburg, K.; Morales, D.

1987-09-01

The inactivation of simian rotavirus Sa-11 and human rotavirus type 2 (Wa) by ozone was compared at 4/sup 0/C by using single-particle virus stocks. Although the human strain was clearly more sensitive, both virus types were rapidly inactivated by ozone concentrations of 0.25 mg/liter or greater at all pH levels tested. Comparison of the virucidal activity of ozone with that of chlorine in identical experiments indicated little significant difference in rotavirus-inactivating efficiencies when the disinfectants were used at concentrations of 0.25 mg/liter or greater.

Mutual inactivation of Notch receptors and ligands facilitates developmental patterning.

Directory of Open Access Journals (Sweden)

David Sprinzak

2011-06-01

Full Text Available Developmental patterning requires juxtacrine signaling in order to tightly coordinate the fates of neighboring cells. Recent work has shown that Notch and Delta, the canonical metazoan juxtacrine signaling receptor and ligand, mutually inactivate each other in the same cell. This cis-interaction generates mutually exclusive sending and receiving states in individual cells. It generally remains unclear, however, how this mutual inactivation and the resulting switching behavior can impact developmental patterning circuits. Here we address this question using mathematical modeling in the context of two canonical pattern formation processes: boundary formation and lateral inhibition. For boundary formation, in a model motivated by Drosophila wing vein patterning, we find that mutual inactivation allows sharp boundary formation across a broader range of parameters than models lacking mutual inactivation. This model with mutual inactivation also exhibits robustness to correlated gene expression perturbations. For lateral inhibition, we find that mutual inactivation speeds up patterning dynamics, relieves the need for cooperative regulatory interactions, and expands the range of parameter values that permit pattern formation, compared to canonical models. Furthermore, mutual inactivation enables a simple lateral inhibition circuit architecture which requires only a single downstream regulatory step. Both model systems show how mutual inactivation can facilitate robust fine-grained patterning processes that would be difficult to implement without it, by encoding a difference-promoting feedback within the signaling system itself. Together, these results provide a framework for analysis of more complex Notch-dependent developmental systems.

A review of cyanobacteria and cyanotoxins removal/inactivation in drinking water treatment.

Science.gov (United States)

Westrick, Judy A; Szlag, David C; Southwell, Benjamin J; Sinclair, James

2010-07-01

This review focuses on the efficiency of different water treatment processes for the removal of cyanotoxins from potable water. Although several investigators have studied full-scale drinking water processes to determine the efficiency of cyanotoxin inactivation, many of the studies were based on ancillary practice. In this context, "ancillary practice" refers to the removal or inactivation of cyanotoxins by standard daily operational procedures and without a contingency operational plan utilizing specific treatment barriers. In this review, "auxiliary practice" refers to the implementation of inactivation/removal treatment barriers or operational changes explicitly designed to minimize risk from toxin-forming algae and their toxins to make potable water. Furthermore, the best drinking water treatment practices are based on extension of the multibarrier approach to remove cyanotoxins from water. Cyanotoxins are considered natural contaminants that occur worldwide and specific classes of cyanotoxins have shown regional prevalence. For example, freshwaters in the Americas often show high concentrations of microcystin, anatoxin-a, and cylindrospermopsin, whereas Australian water sources often show high concentrations of microcystin, cylindrospermopsin, and saxitoxins. Other less frequently reported cyanotoxins include lyngbyatoxin A, debromoaplysiatoxin, and beta-N-methylamino-L-alanine. This review focuses on the commonly used unit processes and treatment trains to reduce the toxicity of four classes of cyanotoxins: the microcystins, cylindrospermopsin, anatoxin-a, and saxitoxins. The goal of this review is to inform the reader of how each unit process participates in a treatment train and how an auxiliary multibarrier approach to water treatment can provide safer water for the consumer.

Sunlight-induced inactivation of human Wa and porcine OSU rotaviruses in the presence of exogenous photosensitizers

KAUST Repository

Romero-Maraccini, Ofelia C.

2013-10-01

Human rotavirus Wa and porcine rotavirus OSU solutions were irradiated with simulated solar UV and visible light in the presence of different photosensitizers dissolved in buffered solutions. For human rotavirus, the exogenous effects were greater than the endogenous effects under irradiation with full spectrum and UVA and visible light at 25 C. For porcine rotavirus, the exogenous effects with UVA and visible light irradiation were only observed at high temperatures, >40 C. The results from dark experiments conducted at different temperatures suggest that porcine rotavirus has higher thermostability than human rotavirus. Concentrations of 3′-MAP excited triplet states of 1.8 fM and above resulted in significant human rotavirus inactivation. The measured excited triplet state concentrations of ≤0.45 fM produced by UVA and visible light irradiation of natural dissolved organic matter solutions were likely not directly responsible for rotavirus inactivation. Instead, the linear correlation for human rotavirus inactivation rate constant (kobs) with the phenol degradation rate constant (kexp) found in both 1 mM NaHCO3 and 1 mM phosphate-buffered solutions suggested that OH radical was a major reactive species for the exogenous inactivation of rotaviruses. Linear correlations between rotavirus kobs and specific UV254 nm absorbance of two river-dissolved organic matter and two effluent organic matter isolates indicated that organic matter aromaticity may help predict formation of radicals responsible for rotavirus inactivation. The results from this study also suggested that the differences in rotavirus strains should be considered when predicting solar inactivation of rotavirus in sunlit surface waters. © 2013 American Chemical Society.

High pressure inactivation of Brettanomyces bruxellensis in red wine.

Science.gov (United States)

van Wyk, Sanelle; Silva, Filipa V M

2017-05-01

Brettanomyces bruxellensis ("Brett") is a major spoilage concern for the wine industry worldwide, leading to undesirable sensory properties. Sulphur dioxide, is currently the preferred method for wine preservation. However, due to its negative effects on consumers, the use of new alternative non-thermal technologies are increasingly being investigated. The aim of this study was to determine and model the effect of high pressure processing (HPP) conditions and yeast strain on the inactivation of "Brett" in Cabernet Sauvignon wine. Processing at 200 MPa for 3 min resulted in 5.8 log reductions. However higher pressure is recommended to achieve high throughput in the wine industry, for example >6.0 log reductions were achieved after 400 MPa for 5 s. The inactivation of B. bruxellensis is pressure and time dependent, with increased treatment time and pressure leading to increased yeast inactivation. It was also found that yeast strain had a significant effect on HPP inactivation, with AWRI 1499 being the most resistant strain. The Weibull model successfully described the HPP "Brett" inactivation. HPP is a viable alternative for the inactivation of B. bruxellensis in wine, with the potential to reduce the industry's reliance on sulphur dioxide. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chlorophyll mediated photodynamic inactivation of blue laser on Streptococcus mutans

Science.gov (United States)

Astuti, Suryani Dyah; Zaidan, A.; Setiawati, Ernie Maduratna; Suhariningsih

2016-03-01

Photodynamic inactivation is an inactivation method in microbial pathogens that utilize light and photosensitizer. This study was conducted to investigate photodynamic inactivation effects of low intensity laser exposure with various dose energy on Streptococcus mutans bacteria. The photodynamic inactivation was achieved with the addition of chlorophyll as photosensitizers. To determine the survival percentage of Streptococcus mutans bacteria after laser exposure, the total plate count method was used. For this study, the wavelength of the laser is 405 nm and variables of energy doses are 1.44, 2.87, 4.31, 5.74, 7.18, and 8.61 in J/cm2. The results show that exposure to laser with energy dose of 7.18 J/cm2 has the best photodynamic inactivation with a decrease of 78% in Streptococcus

Inactivation of RNA Viruses by Gamma Irradiation: A Study on Mitigating Factors

Directory of Open Access Journals (Sweden)

Adam J. Hume

2016-07-01

Full Text Available Effective inactivation of biosafety level 4 (BSL-4 pathogens is vital in order to study these agents safely. Gamma irradiation is a commonly used method for the inactivation of BSL-4 viruses, which among other advantages, facilitates the study of inactivated yet morphologically intact virions. The reported values for susceptibility of viruses to inactivation by gamma irradiation are sometimes inconsistent, likely due to differences in experimental protocols. We analyzed the effects of common sample attributes on the inactivation of a recombinant vesicular stomatitis virus expressing the Zaire ebolavirus glycoprotein and green fluorescent protein. Using this surrogate virus, we found that sample volume and protein content of the sample modulated viral inactivation by gamma irradiation but that air volume within the sample container and the addition of external disinfectant surrounding the sample did not. These data identify several factors which alter viral susceptibility to inactivation and highlight the usefulness of lower biosafety level surrogate viruses for such studies. Our results underscore the need to validate inactivation protocols of BSL-4 pathogens using “worst-case scenario” procedures to ensure complete sample inactivation.

X inactivation in females with X-linked Charcot-Marie-Tooth disease.

LENUS (Irish Health Repository)

Murphy, Sinéad M

2012-07-01

X-linked Charcot-Marie-Tooth disease (CMT1X) is the second most common inherited neuropathy, caused by mutations in gap junction beta-1 (GJB1). Males have a uniformly moderately severe phenotype while females have a variable phenotype, suggested to be due to X inactivation. We aimed to assess X inactivation pattern in females with CMT1X and correlate this with phenotype using the CMT examination score to determine whether the X inactivation pattern accounted for the variable phenotype in females with CMT1X. We determined X inactivation pattern in 67 females with CMT1X and 24 controls using the androgen receptor assay. We were able to determine which X chromosome carried the GJB1 mutation in 30 females. There was no difference in X inactivation pattern between patients and controls. In addition, there was no correlation between X inactivation pattern in blood and phenotype. A possible explanation for these findings is that the X inactivation pattern in Schwann cells rather than in blood may explain the variable phenotype in females with CMT1X.

Inactivation of prion infectivity by ionizing rays

Energy Technology Data Exchange (ETDEWEB)

Gominet, M. [Ionisos, ZI les Chatinieres, F01120 Dagneux (France); Vadrot, C.; Austruy, G. [Paris V University, Central Pharmacy of Hospitals, 4 avenue de l' Observatoire, F-75006, Paris (France); Darbord, J.C. [Paris V University, Central Pharmacy of Hospitals, 4 avenue de l' Observatoire, F-75006, Paris (France)], E-mail: darbord@pharmacie.univ-paris5.fr

2007-11-15

Inactivation of prion deposits on medical devices or prion contamination in pharmaceutical raw materials is considered as impossible by using gamma irradiation. Early, the guideline WHO/CDS/CSR/APH/2000 has described irradiation as an ineffective process. But, in 2003, S. Miekka et al. noted radiation inactivation of prions in a particular application to purify human albumin, shown by the physical denaturation of the infectious protein (PrP). The aim of our study was to determine the inactivation of prions with a scrapie model (strain C506M3) by irradiating standardised preparations. Results: Gamma irradiation was partially effective, showing a 4-5 log reduction on exposure to 50 kGy. A characteristic effect-dose curve was not observed (25, 50 and 100 kGy), only an increase in the incubation period of the murine disease (229 days with 25 kGy to 290 days with 100 kGy) compared with 170 days without irradiation. Since the inactivation was not a total one, the observed effect is significant. It is proposed that further work be undertaken with the model to investigate the application of gamma radiation known levels of prion contamination.

Inactivation of prion infectivity by ionizing rays

International Nuclear Information System (INIS)

Gominet, M.; Vadrot, C.; Austruy, G.; Darbord, J.C.

2007-01-01

Inactivation of prion deposits on medical devices or prion contamination in pharmaceutical raw materials is considered as impossible by using gamma irradiation. Early, the guideline WHO/CDS/CSR/APH/2000 has described irradiation as an ineffective process. But, in 2003, S. Miekka et al. noted radiation inactivation of prions in a particular application to purify human albumin, shown by the physical denaturation of the infectious protein (PrP). The aim of our study was to determine the inactivation of prions with a scrapie model (strain C506M3) by irradiating standardised preparations. Results: Gamma irradiation was partially effective, showing a 4-5 log reduction on exposure to 50 kGy. A characteristic effect-dose curve was not observed (25, 50 and 100 kGy), only an increase in the incubation period of the murine disease (229 days with 25 kGy to 290 days with 100 kGy) compared with 170 days without irradiation. Since the inactivation was not a total one, the observed effect is significant. It is proposed that further work be undertaken with the model to investigate the application of gamma radiation known levels of prion contamination

Thermal and high pressure inactivation kinetics of blueberry peroxidase.

Science.gov (United States)

Terefe, Netsanet Shiferaw; Delon, Antoine; Versteeg, Cornelis

2017-10-01

This study for the first time investigated the stability and inactivation kinetics of blueberry peroxidase in model systems (McIlvaine buffer, pH=3.6, the typical pH of blueberry juice) during thermal (40-80°C) and combined high pressure-thermal processing (0.1-690MPa, 30-90°C). At 70-80°C, the thermal inactivation kinetics was best described by a biphasic model with ∼61% labile and ∼39% stable fractions at temperature between 70 and 75°C. High pressure inhibited the inactivation of the enzyme with no inactivation at pressures as high as 690MPa and temperatures less than 50°C. The inactivation kinetics of the enzyme at 60-70°C, and pressures higher than 500MPa was best described by a first order biphasic model with ∼25% labile fraction and 75% stable fraction. The activation energy values at atmospheric pressure were 548.6kJ/mol and 324.5kJ/mol respectively for the stable and the labile fractions. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Bovine intestinal bacteria inactivate and degrade ceftiofur and ceftriaxone with multiple beta-lactamases.

Science.gov (United States)

Wagner, R Doug; Johnson, Shemedia J; Cerniglia, Carl E; Erickson, Bruce D

2011-11-01

The veterinary cephalosporin drug ceftiofur is rapidly degraded in the bovine intestinal tract. A cylinder-plate assay was used to detect microbiologically active ceftiofur, and high-performance liquid chromatography-mass spectrometry analysis was used to quantify the amount of ceftiofur remaining after incubation with bovine intestinal anaerobic bacteria, which were isolated from colon contents or feces from 8 cattle. Ninety-six percent of the isolates were able to inactivate ceftiofur to some degree, and 54% actually degraded the drug. None of 9 fungal isolates inactivated or degraded ceftiofur. Facultative and obligate anaerobic bacterial species that inactivated or degraded ceftiofur were identified with Vitek and Biolog systems, respectively. A subset of ceftiofur degraders also degraded the chemically similar drug ceftriaxone. Most of the species of bacteria that degraded ceftiofur belonged to the genera Bacillus and Bacteroides. PCR analysis of bacterial DNA detected specific β-lactamase genes. Bacillus cereus and B. mycoides isolates produced extended-spectrum β-lactamases and metallo-β-lactamases. Seven isolates of Bacteroides spp. produced multiple β-lactamases, including possibly CepA, and metallo-β-lactamases. Isolates of Eubacterium biforme, Bifidobacterium breve, and several Clostridium spp. also produced ceftiofur-degrading β-lactamases. An agar gel overlay technique on isoelectric focusing separations of bacterial lysates showed that β-lactamase enzymes were sufficient to degrade ceftiofur. These results suggest that ceftiofur is inactivated nonenzymatically and degraded enzymatically by multiple β-lactamases from bacteria in the large intestines of cattle.

Bovine Intestinal Bacteria Inactivate and Degrade Ceftiofur and Ceftriaxone with Multiple β-Lactamases▿

Science.gov (United States)

Wagner, R. Doug; Johnson, Shemedia J.; Cerniglia, Carl E.; Erickson, Bruce D.

2011-01-01

The veterinary cephalosporin drug ceftiofur is rapidly degraded in the bovine intestinal tract. A cylinder-plate assay was used to detect microbiologically active ceftiofur, and high-performance liquid chromatography-mass spectrometry analysis was used to quantify the amount of ceftiofur remaining after incubation with bovine intestinal anaerobic bacteria, which were isolated from colon contents or feces from 8 cattle. Ninety-six percent of the isolates were able to inactivate ceftiofur to some degree, and 54% actually degraded the drug. None of 9 fungal isolates inactivated or degraded ceftiofur. Facultative and obligate anaerobic bacterial species that inactivated or degraded ceftiofur were identified with Vitek and Biolog systems, respectively. A subset of ceftiofur degraders also degraded the chemically similar drug ceftriaxone. Most of the species of bacteria that degraded ceftiofur belonged to the genera Bacillus and Bacteroides. PCR analysis of bacterial DNA detected specific β-lactamase genes. Bacillus cereus and B. mycoides isolates produced extended-spectrum β-lactamases and metallo-β-lactamases. Seven isolates of Bacteroides spp. produced multiple β-lactamases, including possibly CepA, and metallo-β-lactamases. Isolates of Eubacterium biforme, Bifidobacterium breve, and several Clostridium spp. also produced ceftiofur-degrading β-lactamases. An agar gel overlay technique on isoelectric focusing separations of bacterial lysates showed that β-lactamase enzymes were sufficient to degrade ceftiofur. These results suggest that ceftiofur is inactivated nonenzymatically and degraded enzymatically by multiple β-lactamases from bacteria in the large intestines of cattle. PMID:21876048

Thermal inactivation kinetics of β-galactosidase during bread baking.

Science.gov (United States)

Zhang, Lu; Chen, Xiao Dong; Boom, Remko M; Schutyser, Maarten A I

2017-06-15

In this study, β-galactosidase was utilized as a model enzyme to investigate the mechanism of enzyme inactivation during bread baking. Thermal inactivation of β-galactosidase was investigated in a wheat flour/water system at varying temperature-moisture content combinations, and in bread during baking at 175 or 205°C. In the wheat flour/water system, the thermostability of β-galactosidase increased with decreased moisture content, and a kinetic model was accurately fitted to the corresponding inactivation data (R 2 =0.99). Interestingly, the residual enzyme activity in the bread crust (about 30%) was hundredfold higher than that in the crumb (about 0.3%) after baking, despite the higher temperature in the crust throughout baking. This result suggested that the reduced moisture content in the crust increased the thermostability of the enzyme. Subsequently, the kinetic model reasonably predicted the enzyme inactivation in the crumb using the same parameters derived from the wheat flour/water system. However, the model predicted a lower residual enzyme activity in the crust compared with the experimental result, which indicated that the structure of the crust may influence the enzyme inactivation mechanism during baking. The results reported can provide a quantitative understanding of the thermal inactivation kinetics of enzyme during baking, which is essential to better retain enzymatic activity in bakery products supplemented with heat-sensitive enzymes. Copyright © 2017 Elsevier Ltd. All rights reserved.

A tritherapy combination of inactivated allogeneic leukocytes infusion and cell vaccine with cyclophosphamide in a sequential regimen enhances antitumor immunity

OpenAIRE

Yishu Tang; Wenbo Ma; Chunxia Zhou; Dongmei Wang; Shuren Zhang

2018-01-01

Background: Tumor-induced immunosuppression can impede tumor-specific immune responses and limit the effects of cancer immunotherapy. The aim of this study was to investigate the possible effects of sequential chemoimmunotherapeutic strategies to enhance antitumor immune responses. Methods: Using the E7-expressing tumor TC-1 as the tumor model, the treatment groups were divided into the following groups: (1) inactivated allogeneic leukocyte infusion (ALI), (2) ALI + MMC-inactivated TC-1 cell ...

TFPI-2 is a putative tumor suppressor gene frequently inactivated by promoter hypermethylation in nasopharyngeal carcinoma

International Nuclear Information System (INIS)

Wang, Shumin; Ma, Ning; Murata, Mariko; Huang, Guangwu; Zhang, Zhe; Xiao, Xue; Zhou, Xiaoying; Huang, Tingting; Du, Chunping; Yu, Nana; Mo, Yingxi; Lin, Longde; Zhang, Jinyan

2010-01-01

Epigenetic silencing of tumor suppressor genes play important roles in NPC tumorgenesis. Tissue factor pathway inhibitor-2 (TFPI-2), is a protease inhibitor. Recently, TFPI-2 was suggested to be a tumor suppressor gene involved in tumorigenesis and metastasis in some cancers. In this study, we investigated whether TFPI-2 was inactivated epigenetically in nasopharyngeal carcinoma (NPC). Transcriptional expression levels of TFPI-2 was evaluated by RT-PCR. Methylation status were investigated by methylation specific PCR and bisulfate genomic sequencing. The role of TFPI-2 as a tumor suppressor gene in NPC was addressed by re-introducing TFPI-2 expression into the NPC cell line CNE2. TFPI-2 mRNA transcription was inactivated in NPC cell lines. TFPI-2 was aberrantly methylated in 66.7% (4/6) NPC cell lines and 88.6% (62/70) of NPC primary tumors, but not in normal nasopharyngeal epithelia. TFPI-2 expression could be restored in NPC cells after demethylation treatment. Ectopic expression of TFPI-2 in NPC cells induced apoptosis and inhibited cell proliferation, colony formation and cell migration. Epigenetic inactivation of TFPI-2 by promoter hypermethylation is a frequent and tumor specific event in NPC. TFPI-2 might be considering as a putative tumor suppressor gene in NPC

Modeling-independent elucidation of inactivation pathways in recombinant and native A-type Kv channels

Science.gov (United States)

Fineberg, Jeffrey D.; Ritter, David M.

2012-01-01

A-type voltage-gated K+ (Kv) channels self-regulate their activity by inactivating directly from the open state (open-state inactivation [OSI]) or by inactivating before they open (closed-state inactivation [CSI]). To determine the inactivation pathways, it is often necessary to apply several pulse protocols, pore blockers, single-channel recording, and kinetic modeling. However, intrinsic hurdles may preclude the standardized application of these methods. Here, we implemented a simple method inspired by earlier studies of Na+ channels to analyze macroscopic inactivation and conclusively deduce the pathways of inactivation of recombinant and native A-type Kv channels. We investigated two distinct A-type Kv channels expressed heterologously (Kv3.4 and Kv4.2 with accessory subunits) and their native counterparts in dorsal root ganglion and cerebellar granule neurons. This approach applies two conventional pulse protocols to examine inactivation induced by (a) a simple step (single-pulse inactivation) and (b) a conditioning step (double-pulse inactivation). Consistent with OSI, the rate of Kv3.4 inactivation (i.e., the negative first derivative of double-pulse inactivation) precisely superimposes on the profile of the Kv3.4 current evoked by a single pulse because the channels must open to inactivate. In contrast, the rate of Kv4.2 inactivation is asynchronous, already changing at earlier times relative to the profile of the Kv4.2 current evoked by a single pulse. Thus, Kv4.2 inactivation occurs uncoupled from channel opening, indicating CSI. Furthermore, the inactivation time constant versus voltage relation of Kv3.4 decreases monotonically with depolarization and levels off, whereas that of Kv4.2 exhibits a J-shape profile. We also manipulated the inactivation phenotype by changing the subunit composition and show how CSI and CSI combined with OSI might affect spiking properties in a full computational model of the hippocampal CA1 neuron. This work unambiguously

Thermal inactivation of enzymes and pathogens in biosamples for MS analysis.

Science.gov (United States)

Ahnoff, Martin; Cazares, Lisa H; Sköld, Karl

2015-01-01

Protein denaturation is the common basis for enzyme inactivation and inactivation of pathogens, necessary for preservation and safe handling of biosamples for downstream analysis. While heat-stabilization technology has been used in proteomic and peptidomic research since its introduction in 2009, the advantages of using the technique for simultaneous pathogen inactivation have only recently been addressed. The time required for enzyme inactivation by heat (≈1 min) is short compared with chemical treatments, and inactivation is irreversible in contrast to freezing. Heat stabilization thus facilitates mass spectrometric studies of biomolecules with a fast conversion rate, and expands the chemical space of potential biomarkers to include more short-lived entities, such as phosphorylated proteins, in tissue samples as well as whole-blood (dried blood sample) samples.

Cortical inactivation by cooling in small animals

Directory of Open Access Journals (Sweden)

Ben eCoomber

2011-06-01

Full Text Available Reversible inactivation of the cortex by surface cooling is a powerful method for studying the function of a particular area. Implanted cooling cryoloops have been used to study the role of individual cortical areas in auditory processing of awake-behaving cats. Cryoloops have also been used in rodents for reversible inactivation of the cortex, but recently there has been a concern that the cryoloop may also cool non-cortical structures either directly or via the perfusion of blood, cooled as it passed close to the cooling loop. In this study we have confirmed that the loop can inactivate most of the auditory cortex without causing a significant reduction in temperature of the auditory thalamus or other sub-cortical structures. We placed a cryoloop on the surface of the guinea pig cortex, cooled it to 2°C and measured thermal gradients across the neocortical surface. We found that the temperature dropped to 20-24°C among cells within a radius of about 2.5mm away from the loop. This temperature drop was sufficient to reduce activity of most cortical cells and led to the inactivation of almost the entire auditory region. When the temperature of thalamus, midbrain, and middle ear were measured directly during cortical cooling, there was a small drop in temperature (about 4°C but this was not sufficient to directly reduce neural activity. In an effort to visualise the extent of neural inactivation we measured the uptake of thallium ions following an intravenous injection. This confirmed that there was a large reduction of activity across much of the ipsilateral cortex and only a small reduction in subcortical structures.

Inactivation as a new regulatory mechanism for neuronal Kv7 channels

DEFF Research Database (Denmark)

Jensen, Henrik Sindal; Grunnet, Morten; Olesen, Søren-Peter

2007-01-01

neuronal channels and are important for controlling excitability. Kv7.1 channels have been considered the only Kv7 channels to undergo inactivation upon depolarization. However, here we demonstrate that inactivation is also an intrinsic property of Kv7.4 and Kv7.5 channels, which inactivate to a larger...

Quantum chromodynamics as the sequential fragmenting with inactivation

International Nuclear Information System (INIS)

Botet, R.

1996-01-01

We investigate the relation between the modified leading log approximation of the perturbative QCD and the sequential binary fragmentation process. We will show that in the absence of inactivation, this process is equivalent to the QCD gluodynamics. The inactivation term yields a precise prescription of how to include the hadronization in the QCD equations. (authors)

Scale down of the inactivated polio vaccine production process

NARCIS (Netherlands)

Thomassen, Y.E.; Oever, van 't R.; Vinke, C.M.; Spiekstra, A.; Wijffels, R.H.; Pol, van der L.A.; Bakker, W.A.M.

2013-01-01

The anticipated increase in the demand for inactivated polio vaccines resulting from the success in the polio eradication program requires an increase in production capacity and cost price reduction of the current inactivated polio vaccine production processes. Improvement of existing production

Inactivation of Escherichia coli Endotoxin by Soft Hydrothermal Processing▿

Science.gov (United States)

Miyamoto, Toru; Okano, Shinya; Kasai, Noriyuki

2009-01-01

Bacterial endotoxins, also known as lipopolysaccharides, are a fever-producing by-product of gram-negative bacteria commonly known as pyrogens. It is essential to remove endotoxins from parenteral preparations since they have multiple injurious biological activities. Because of their strong heat resistance (e.g., requiring dry-heat sterilization at 250°C for 30 min) and the formation of various supramolecular aggregates, depyrogenation is more difficult than sterilization. We report here that soft hydrothermal processing, which has many advantages in safety and cost efficiency, is sufficient to assure complete depyrogenation by the inactivation of endotoxins. The endotoxin concentration in a sample was measured by using a chromogenic limulus method with an endotoxin-specific limulus reagent. The endotoxin concentration was calculated from a standard curve obtained using a serial dilution of a standard solution. We show that endotoxins were completely inactivated by soft hydrothermal processing at 130°C for 60 min or at 140°C for 30 min in the presence of a high steam saturation ratio or with a flow system. Moreover, it is easy to remove endotoxins from water by soft hydrothermal processing similarly at 130°C for 60 min or at 140°C for 30 min, without any requirement for ultrafiltration, nonselective adsorption with a hydrophobic adsorbent, or an anion exchanger. These findings indicate that soft hydrothermal processing, applied in the presence of a high steam saturation ratio or with a flow system, can inactivate endotoxins and may be useful for the depyrogenation of parenterals, including end products and medical devices that cannot be exposed to the high temperatures of dry heat treatments. PMID:19502435

Cytolytic T lymphocyte responses to metabolically inactivated stimulator cells. I. Metabolic inactivation impairs both CD and LD antigen signals

International Nuclear Information System (INIS)

Kelso, A.; Boyle, W.

1982-01-01

The effects of metabolic inactivation of spleen cells on antigen presentation to precursors of alloreactive cytolytic T lymphocytes (T/sub c/) were examined. By serological methods, populations inactivated by ultraviolet irradiation, glutaraldehyde fixation or plasma membrane isolation were found to retain normal levels of H-2K/D and Ia antigens. However, comparison of the antigen doses required to stimulate secondary T/sub c/ responses in mixed leukocyte culture showed that the inactivated preparations were approximately 10-fold less immunogenic than X-irradiated spleen cells. Their total inability to stimulate primary cytolytic responses pointed to at least a 100-fold impairment of immunogenicity for unprimed T/sub c/ precursors in the case of uv-irradiated and glutaraldehyde-treated stimulator cells, and at least a 10-fold impairment for membrane fragments. Experiments showing that the capacity of cell monolayers to absorb precursor T/sub c/ from unprimed spleen populations was reduced following uv-irradiation or glutaraldehyde treatment provided direct evidence that this loss of immunogenicity was due in part to suboptimal antigen presentation to precursor T/sub c/. It is concluded that, in addition to the traditional view that these treatments damage the ''LD'' signal to helper T lymphocytes, metabolic inactivation also impairs recognition of ''CD'' determinants by precursor T/sub c/

Quantum chromodynamics as the sequential fragmenting with inactivation

Energy Technology Data Exchange (ETDEWEB)

Botet, R. [Paris-11 Univ., 91 - Orsay (France). Lab. de Physique des Solides; Ploszajczak, M. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France)

1996-12-31

We investigate the relation between the modified leading log approximation of the perturbative QCD and the sequential binary fragmentation process. We will show that in the absence of inactivation, this process is equivalent to the QCD gluodynamics. The inactivation term yields a precise prescription of how to include the hadronization in the QCD equations. (authors). 15 refs.

The roles of the various plasma agents in the inactivation of bacteria

International Nuclear Information System (INIS)

Lu Xinpei; Xiong Qing; Tang Zhiyuan; Xiong Zhilan; Hu Jing; Jiang Zhonghe; Pan Yuan; Ye Tao; Cao Yingguang; Sun Ziyong

2008-01-01

The roles of various plasma agents in the inactivation of bacteria have recently been investigated. However, up to now, the effect of the charged particles on the inactivation of bacteria is not well understood. In this paper, an atmospheric pressure plasma jet device, which generates a cold plasma plume carrying a peak current of 300 mA, is used to investigate the role of the charged particles in the inactivation process. It is found that the charged particles play a minor role in the inactivation process when He/N 2 (3%) is used as working gas. On the other hand, when He/O 2 (3%) is used, the charged particles are expected to play an important role in the inactivation of bacteria. Further analysis shows that the negative ions O 2 - might be the charged particles that are playing the role. Besides, it is found that the active species, including O, O 3 , and metastable state O 2 *, can play a crucial role in the inactivation of the bacteria. However, the excited He*, N 2 C 3 Π u , and N 2 + B 2 Σ u + have no significant direct effect on the inactivation of bacteria. It is also concluded that heat and UV play no or minor role in the inactivation process

Mechanism of Cd2+-coordination during Slow Inactivation in Potassium Channels

Science.gov (United States)

Raghuraman, H.; Cordero-Morales, Julio F.; Jogini, Vishwanath; Pan, Albert C.; Kollewe, Astrid; Roux, Benoît; Perozo, Eduardo

2013-01-01

Summary In K+ channels, rearrangements of the pore outer-vestibule have been associated with C-type inactivation gating. Paradoxically, the crystal structure of Open/C-type inactivated KcsA suggest these movements to be modest in magnitude. Here, we show that under physiological conditions, the KcsA outer-vestibule undergoes relatively large dynamic rearrangements upon inactivation. External Cd2+ enhances the rate of C-type inactivation in an outer-vestibule cysteine mutant (Y82C) via metal-bridge formation. This effect is not present in a non-inactivating mutant (E71A/Y82C). Tandem dimer and tandem tetramer constructs of equivalent cysteine mutants in KcsA and Shaker K+ channels demonstrate that these Cd2+ metal bridges are formed only between adjacent subunits. This is well supported by molecular dynamics simulations. Based on the crystal structure of Cd2+-bound Y82C-KcsA in the closed state, together with EPR distance measurements in the KcsA outer-vestibule, we suggest that subunits must dynamically come in close proximity as the channels undergo inactivation. PMID:22771214

Quantitative analysis of wet-heat inactivation in bovine spongiform encephalopathy

International Nuclear Information System (INIS)

Matsuura, Yuichi; Ishikawa, Yukiko; Bo, Xiao; Murayama, Yuichi; Yokoyama, Takashi; Somerville, Robert A.; Kitamoto, Tetsuyuki; Mohri, Shirou

2013-01-01

Highlights: ► We quantitatively analyzed wet-heat inactivation of the BSE agent. ► Infectivity of the BSE macerate did not survive 155 °C wet-heat treatment. ► Once the sample was dehydrated, infectivity was observed even at 170 °C. ► A quantitative PMCA assay was used to evaluate the degree of BSE inactivation. - Abstract: The bovine spongiform encephalopathy (BSE) agent is resistant to conventional microbial inactivation procedures and thus threatens the safety of cattle products and by-products. To obtain information necessary to assess BSE inactivation, we performed quantitative analysis of wet-heat inactivation of infectivity in BSE-infected cattle spinal cords. Using a highly sensitive bioassay, we found that infectivity in BSE cattle macerates fell with increase in temperatures from 133 °C to 150 °C and was not detected in the samples subjected to temperatures above 155 °C. In dry cattle tissues, infectivity was detected even at 170 °C. Thus, BSE infectivity reduces with increase in wet-heat temperatures but is less affected when tissues are dehydrated prior to the wet-heat treatment. The results of the quantitative protein misfolding cyclic amplification assay also demonstrated that the level of the protease-resistant prion protein fell below the bioassay detection limit by wet-heat at 155 °C and higher and could help assess BSE inactivation. Our results show that BSE infectivity is strongly resistant to wet-heat inactivation and that it is necessary to pay attention to BSE decontamination in recycled cattle by-products

Quantitative analysis of wet-heat inactivation in bovine spongiform encephalopathy

Energy Technology Data Exchange (ETDEWEB)

Matsuura, Yuichi; Ishikawa, Yukiko; Bo, Xiao; Murayama, Yuichi; Yokoyama, Takashi [Prion Disease Research Center, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856 (Japan); Somerville, Robert A. [The Roslin Institute and Royal (Dick) School of Veterinary Studies, Roslin, Midlothian, EH25 9PS (United Kingdom); Kitamoto, Tetsuyuki [Division of CJD Science and Technology, Department of Prion Research, Center for Translational and Advanced Animal Research on Human Diseases, Tohoku University Graduate School of Medicine, 2-1 Seiryo, Aoba, Sendai 980-8575 (Japan); Mohri, Shirou, E-mail: shirou@affrc.go.jp [Prion Disease Research Center, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856 (Japan)

2013-03-01

Highlights: ► We quantitatively analyzed wet-heat inactivation of the BSE agent. ► Infectivity of the BSE macerate did not survive 155 °C wet-heat treatment. ► Once the sample was dehydrated, infectivity was observed even at 170 °C. ► A quantitative PMCA assay was used to evaluate the degree of BSE inactivation. - Abstract: The bovine spongiform encephalopathy (BSE) agent is resistant to conventional microbial inactivation procedures and thus threatens the safety of cattle products and by-products. To obtain information necessary to assess BSE inactivation, we performed quantitative analysis of wet-heat inactivation of infectivity in BSE-infected cattle spinal cords. Using a highly sensitive bioassay, we found that infectivity in BSE cattle macerates fell with increase in temperatures from 133 °C to 150 °C and was not detected in the samples subjected to temperatures above 155 °C. In dry cattle tissues, infectivity was detected even at 170 °C. Thus, BSE infectivity reduces with increase in wet-heat temperatures but is less affected when tissues are dehydrated prior to the wet-heat treatment. The results of the quantitative protein misfolding cyclic amplification assay also demonstrated that the level of the protease-resistant prion protein fell below the bioassay detection limit by wet-heat at 155 °C and higher and could help assess BSE inactivation. Our results show that BSE infectivity is strongly resistant to wet-heat inactivation and that it is necessary to pay attention to BSE decontamination in recycled cattle by-products.

THE ANTIGENIC POTENCY OF EPIDEMIC INFLUENZA VIRUS FOLLOWING INACTIVATION BY ULTRAVIOLET RADIATION

Science.gov (United States)

Salk, Jonas E.; Lavin, G. I.; Francis, Thomas

1940-01-01

A study of the antigenic potency of influenza virus inactivated by ultraviolet radiation has been made. Virus so inactivated is still capable of functioning as an immunizing agent when given to mice by the intraperitoneal route. In high concentrations inactivated virus appears to be nearly as effective as active virus but when quantitative comparisons of the immunity induced by different dilutions are made, it is seen that a hundredfold loss in immunizing capacity occurs during inactivation. Virus in suspensions prepared from the lungs of infected mice is inactivated more rapidly than virus in tissue culture medium. A standard for the comparison of vaccines of epidemic influenza virus is proposed. PMID:19871057

Fullerene C60 and graphene photosensibiles for photodynamic virus inactivation

Science.gov (United States)

Belousova, I.; Hvorostovsky, A.; Kiselev, V.; Zarubaev, V.; Kiselev, O.; Piotrovsky, L.; Anfimov, P.; Krisko, T.; Muraviova, T.; Rylkov, V.; Starodubzev, A.; Sirotkin, A.; Grishkanich, A.; Kudashev, I.; Kancer, A.; Kustikova, M.; Bykovskaya, E.; Mayurova, A.; Stupnikov, A.; Ruzankina, J.; Afanasyev, M.; Lukyanov, N.; Redka, D.; Paklinov, N.

2018-02-01

A solid-phase photosensitizer based on aggregated C60 fullerene and graphene oxide for photodynamic inactivation of pathogens in biological fluids was studied. The most promising technologies of inactivation include the photodynamic effect, which consists in the inactivation of infectious agents by active oxygen forms (including singlet oxygen), formed when light is activated by the photosensitizer introduced into the plasma. Research shows features of solid-phase systems based on graphene and fullerene C60 oxide, which is a combination of an effective inactivating pathogens (for example, influenza viruses) reactive oxygen species formed upon irradiation of the photosensitizer in aqueous and biological fluids, a high photostability fullerene coatings and the possibility of full recovery photosensitizer from the biological environment after the photodynamic action.

Thermal inactivation kinetics of β-galactosidase during bread baking

NARCIS (Netherlands)

Zhang, L.; Chen, Xiao Dong; Boom, R.M.; Schutyser, M.A.I.

2017-01-01

In this study, β-galactosidase was utilized as a model enzyme to investigate the mechanism of enzyme inactivation during bread baking. Thermal inactivation of β-galactosidase was investigated in a wheat flour/water system at varying temperature-moisture content combinations, and in bread during

Ebola Virus Inactivation by Detergents Is Annulled in Serum

NARCIS (Netherlands)

van Kampen, Jeroen J. A.; Tintu, Andrei; Russcher, Henk; Fraaij, Pieter L. A.; Reusken, Chantal B. E. M.; Rijken, Mikel; van Hellemond, Jaap J.; van Genderen, Perry J. J.; Koelewijn, Rob; de Jong, Menno D.; Haddock, Elaine; Fischer, Robert J.; Munster, Vincent J.; Koopmans, Marion P. G.

2017-01-01

Treatment of blood samples from hemorrhagic fever virus (HFV)-infected patients with 0.1% detergents has been recommended for virus inactivation and subsequent safe laboratory testing. However, data on virus inactivation by this procedure are lacking. Here we show the effect of this procedure on

N- vs. C-Domain Selectivity of Catalytic Inactivation of Human Angiotensin Converting Enzyme by Lisinopril-Coupled Transition Metal Chelates

Science.gov (United States)

Hocharoen, Lalintip; Joyner, Jeff C.; Cowan, J. A.

2014-01-01

The N- and C-terminal domains of human somatic Angiotensin I Converting Enzyme (sACE-1) demonstrate distinct physiological functions, with resulting interest in the development of domain-selective inhibitors for specific therapeutic applications. Herein, the activity of lisinopril-coupled transition metal chelates were tested for both reversible binding and irreversible catalytic inactivation of sACE-1. C/N domain binding selectivity ratios ranged from 1 to 350, while rates of irreversible catalytic inactivation of the N- and C-domains were found to be significantly greater for the N-domain, suggesting a more optimal orientation of the M-chelate-lisinopril complexes within the active site of the N-domain of sACE-1. Finally, the combined effect of binding selectivity and inactivation selectivity was assessed for each catalyst (double-filter selectivity factors), and several catalysts were found to cause domain-selective catalytic inactivation. The results of this study demonstrate the ability to optimize the target selectivity of catalytic metallopeptides through both binding and orientation factors (double-filter effect). PMID:24228790

N- versus C-domain selectivity of catalytic inactivation of human angiotensin converting enzyme by lisinopril-coupled transition metal chelates.

Science.gov (United States)

Hocharoen, Lalintip; Joyner, Jeff C; Cowan, J A

2013-12-27

The N- and C-terminal domains of human somatic angiotensin I converting enzyme (sACE-1) demonstrate distinct physiological functions, with resulting interest in the development of domain-selective inhibitors for specific therapeutic applications. Herein, the activity of lisinopril-coupled transition metal chelates was tested for both reversible binding and irreversible catalytic inactivation of each domain of sACE-1. C/N domain binding selectivity ratios ranged from 1 to 350, while rates of irreversible catalytic inactivation of the N- and C-domains were found to be significantly greater for the N-domain, suggesting a more optimal orientation of M-chelate-lisinopril complexes within the active site of the N-domain of sACE-1. Finally, the combined effect of binding selectivity and inactivation selectivity was assessed for each catalyst (double-filter selectivity factors), and several catalysts were found to cause domain-selective catalytic inactivation. The results of this study demonstrate the ability to optimize the target selectivity of catalytic metallopeptides through both binding and catalytic factors (double-filter effect).

Rapid Bedside Inactivation of Ebola Virus for Safe Nucleic Acid Tests

DEFF Research Database (Denmark)

Rosenstierne, Maiken Worsøe; Karlberg, Helen; Bragstad, Karoline

2016-01-01

Rapid bedside inactivation of Ebola virus would be a solution for the safety of medical and technical staff, risk containment, sample transport, and high-throughput or rapid diagnostic testing during an outbreak. We show that the commercially available Magna Pure lysis/binding buffer used...... for nucleic acid extraction inactivates Ebola virus. A rapid bedside inactivation method for nucleic acid tests is obtained by simply adding Magna Pure lysis/binding buffer directly into vacuum blood collection EDTA tubes using a thin needle and syringe prior to sampling. The ready-to-use inactivation vacuum...... tubes are stable for more than 4 months, and Ebola virus RNA is preserved in the Magna Pure lysis/binding buffer for at least 5 weeks independent of the storage temperature. We also show that Ebola virus RNA can be manually extracted from Magna Pure lysis/binding buffer-inactivated samples using...

Tissue-specific inactivation of type 2 deiodinase reveals multilevel control of fatty acid oxidation by thyroid hormone in the mouse.

Science.gov (United States)

Fonseca, Tatiana L; Werneck-De-Castro, Joao Pedro; Castillo, Melany; Bocco, Barbara M L C; Fernandes, Gustavo W; McAninch, Elizabeth A; Ignacio, Daniele L; Moises, Caio C S; Ferreira, Alexander R; Ferreira, Alexandre; Gereben, Balázs; Bianco, Antonio C

2014-05-01

Type 2 deiodinase (D2) converts the prohormone thyroxine (T4) to the metabolically active molecule 3,5,3'-triiodothyronine (T3), but its global inactivation unexpectedly lowers the respiratory exchange rate (respiratory quotient [RQ]) and decreases food intake. Here we used FloxD2 mice to generate systemically euthyroid fat-specific (FAT), astrocyte-specific (ASTRO), or skeletal-muscle-specific (SKM) D2 knockout (D2KO) mice that were monitored continuously. The ASTRO-D2KO mice also exhibited lower diurnal RQ and greater contribution of fatty acid oxidation to energy expenditure, but no differences in food intake were observed. In contrast, the FAT-D2KO mouse exhibited sustained (24 h) increase in RQ values, increased food intake, tolerance to glucose, and sensitivity to insulin, all supporting greater contribution of carbohydrate oxidation to energy expenditure. Furthermore, FAT-D2KO animals that were kept on a high-fat diet for 8 weeks gained more body weight and fat, indicating impaired brown adipose tissue (BAT) thermogenesis and/or inability to oxidize the fat excess. Acclimatization of FAT-D2KO mice at thermoneutrality dissipated both features of this phenotype. Muscle D2 does not seem to play a significant metabolic role given that SKM-D2KO animals exhibited no phenotype. The present findings are unique in that they were obtained in systemically euthyroid animals, revealing that brain D2 plays a dominant albeit indirect role in fatty acid oxidation via its sympathetic control of BAT activity. D2-generated T3 in BAT accelerates fatty acid oxidation and protects against diet-induced obesity.

Inactivation of human and simian rotaviruses by chlorine dioxide

Energy Technology Data Exchange (ETDEWEB)

Chen, Yu-Shiaw (Brookhaven National Lab., Upton, NY (USA)); Vaughn, J.M. (Univ. of New England College of Medicine, Biddeford, ME (USA))

1990-05-01

The inactivation of single-particle stocks of human (type 2, Wa) and simian (SA-11) rotaviruses by chlorine dioxide was investigated. Experiments were conducted at 4{degree}C in a standard phosphate-carbonate buffer. Both virus types were rapidly inactivated, within 20 s under alkaline conditions, when chlorine dioxide concentrations ranging from 0.05 to 0.2 mg/liter were used. Similar reductions of 10{sup 5}-fold in infectivity required additional exposure time of 120 s at 0.2 mg/liter for Wa and at 0.5 mg/liter for SA-11, respectively, at pH 6.0. The inactivation of both virus types was moderate a neutral pH, and the sensitivities to chlorine dioxide were similar. The observed enhancement of virucidal efficiency with increasing pH was contrary to earlier findings with chlorine- and ozone-treated rotavirus particles, where efficiencies decreased with increasing alkalinity. Comparison of 99.9% virus inactivation times revealed ozone to be the most effective virucidal agent among these three disinfectants.

Inactivation of Paragonimus westermani metacercariae in soy sauce-marinated and frozen freshwater crabs.

Science.gov (United States)

Kim, Tae Im; Oh, Se-Ra; Dai, Fuhong; Yang, Hyun-Jong; Ha, Sang-Do; Hong, Sung-Jong

2017-03-01

Soy sauce-marinated freshwater crabs (Eriocheir japonicus) are a source of human paragonimiasis. The viability of Paragonimus westermani metacercariae (PwMc) in marinated crabs was investigated in an experimental setting. The PwMc collected from freshwater crayfish were inoculated into freshwater crabs, which were then frozen or marinated in soy sauce. All PwMc in the freshwater crabs were inactivated after freezing for 48 h at -20 °C and after freezing for 12 h at -40 °C. After marinating for 32 days, the survival rate of PwMc in 5% NaCl soy sauce was 50%, in 7.5% NaCl soy sauce it was 33.3%, and in 10.0% NaCl soy sauce it was 31.3%. When marinated for 64 days, all PwMc were inactivated in all experimental groups. These results revealed that freezing and soy sauce marination were detrimental to the survival of PwMc in freshwater crabs. Specifically, freezing crabs for more than 48 h or soaking them in soy sauce containing at least 5.0% NaCl for 64 days can inactivate PwMc. These results can inform the production of the traditional Korean soy sauce-marinated freshwater crabs known as gejang.

The inactivation of papain by high LET radiations

International Nuclear Information System (INIS)

Bisby, R.H.; Cundall, R.B.; Sims, H.E.; Burns, W.G.

1984-01-01

The effect of varying LET over a wide range (0.2-1570 eV/nm) on the radiation-induced inactivation of the enzyme papain in dilute aqueous solution has been investigated. Measurements of total, reparable and non-reparable inactivation G values in oxygen, nitrous oxide and argon saturated solutions have allowed the contributions to inactivation from radicals and hydrogen peroxide to be evaluated. At high LET the results demonstrate an increasing component due to reaction of the superoxide radical, formed from oxygen produced in the track as a primary radiolysis product. This effect was not observed in our previous study with ribonuclease due to the insensitivity of ribonuclease to inactivation by superoxide and hydrogen peroxide. The results obtained with papain clearly demonstrate a maximum in G(H 2 O 2 ) at an LET of equivalent to 140 eV/nm. Generation of O 2 within the track as a primary radiolysis product at high LET now appears to be confirmed as an important mechanism leading to reduction in the oxygen enhancement ratio for cellular systems exposed to high LET radiations (Baverstock and Burns 1981). (author)

Design and mechanism of tetrahydrothiophene-based γ-aminobutyric acid aminotransferase inactivators.

Science.gov (United States)

Le, Hoang V; Hawker, Dustin D; Wu, Rui; Doud, Emma; Widom, Julia; Sanishvili, Ruslan; Liu, Dali; Kelleher, Neil L; Silverman, Richard B

2015-04-08

Low levels of γ-aminobutyric acid (GABA), one of two major neurotransmitters that regulate brain neuronal activity, are associated with many neurological disorders, such as epilepsy, Parkinson's disease, Alzheimer's disease, Huntington's disease, and cocaine addiction. One of the main methods to raise the GABA level in human brain is to use small molecules that cross the blood-brain barrier and inhibit the activity of γ-aminobutyric acid aminotransferase (GABA-AT), the enzyme that degrades GABA. We have designed a series of conformationally restricted tetrahydrothiophene-based GABA analogues with a properly positioned leaving group that could facilitate a ring-opening mechanism, leading to inactivation of GABA-AT. One compound in the series is 8 times more efficient an inactivator of GABA-AT than vigabatrin, the only FDA-approved inactivator of GABA-AT. Our mechanistic studies show that the compound inactivates GABA-AT by a new mechanism. The metabolite resulting from inactivation does not covalently bind to amino acid residues of GABA-AT but stays in the active site via H-bonding interactions with Arg-192, a π-π interaction with Phe-189, and a weak nonbonded S···O═C interaction with Glu-270, thereby inactivating the enzyme.

Design and Mechanism of Tetrahydrothiophene-Based γ-Aminobutyric Acid Aminotransferase Inactivators

Energy Technology Data Exchange (ETDEWEB)

Le, Hoang V. [Departments; Hawker, Dustin D. [Departments; Wu, Rui [Department; Doud, Emma [Departments; Widom, Julia [Departments; Sanishvili, Ruslan [X-ray; Liu, Dali [Department; Kelleher, Neil L. [Departments; Silverman, Richard B. [Departments

2015-03-25

Low levels of gamma-aminobutyric acid (GABA), one of two major neurotransmitters that regulate brain neuronal activity, are associated with many neurological disorders, such as epilepsy, Parkinsons disease, Alzheimers disease, Huntingtons disease, and cocaine addiction. One of the main methods to raise the GABA level in human brain is to use small molecules that cross the bloodbrain barrier and inhibit the activity of gamma-aminobutyric acid aminotransferase (GABA-AT), the enzyme that degrades GABA. We have designed a series of conformationally restricted tetrahydrothiophene-based GABA analogues with a properly positioned leaving group that could facilitate a ring-opening mechanism, leading to inactivation of GABA-AT. One compound in the series is 8 times more efficient an inactivator of GABA-AT than vigabatrin, the only FDA-approved inactivator of GABA-AT. Our mechanistic studies show that the compound inactivates GABA-AT by a new mechanism. The metabolite resulting from inactivation does not covalently bind to amino acid residues of GABA-AT but stays in the active site via H-bonding interactions with Arg-192, a pi-pi interaction with Phe-189, and a weak nonbonded (SO)-O-...=C interaction with Glu-270, thereby inactivating the enzyme.

Gamma-irradiation to inactivate thioglucosidase of crucifers

International Nuclear Information System (INIS)

Lessman, K.J.; McCaslin, B.D.

1987-01-01

The crucifers contain glucosinolates which through enzymatic hydrolysis give rise to toxicants that limit the use of oil-free meal obtainable from this plant family. Seeds from three crucifers were used to test gamma irradiation to inactivate enzyme systems as a step toward detoxification. Seeds of Crambe abyssinica Hochst (crambe), ground seeds of Sinapis alba L. (mustard), and seeds of Brassica napus L. (rape) were subjected to gamma-irradiation (6.25, 12.5, 25.0 and 50.4 Mrad) to inactivate thioglucosidase and/or destroy glucosinolates. Samples of ground seeds, their oil-free meals, previously irradiated ground seeds and their oil-free meals were assayed for glucose, a product of enzymatic hydrolysis of glucosinolates present in the crucifer seeds. The 50.4 Mrad exposure inactivated thioglucosidase but did not destroy glucosinolates. The fatty acid contents of extracted oils were affected. The amino acid profile of defatted crambe protein meal was affected, while that of white mustard was not

Susceptibility of glucokinase-MODY mutants to inactivation by oxidative stress in pancreatic β-cells.

Science.gov (United States)

Cullen, Kirsty S; Matschinsky, Franz M; Agius, Loranne; Arden, Catherine

2011-12-01

The posttranslational regulation of glucokinase (GK) differs in hepatocytes and pancreatic β-cells. We tested the hypothesis that GK mutants that cause maturity-onset diabetes of the young (GK-MODY) show compromised activity and posttranslational regulation in β-cells. Activity and protein expression of GK-MODY and persistent hyperinsulinemic hypoglycemia of infancy (PHHI) mutants were studied in β-cell (MIN6) and non-β-cell (H4IIE) models. Binding of GK to phosphofructo-2-kinase, fructose-2,6-bisphosphatase (PFK2/FBPase2) was studied by bimolecular fluorescence complementation in cell-based models. Nine of 11 GK-MODY mutants that have minimal effect on enzyme kinetics in vitro showed decreased specific activity relative to wild type when expressed in β-cells. A subset of these were stable in non-β-cells but showed increased inactivation in conditions of oxidative stress and partial reversal of inactivation by dithiothreitol. Unlike the GK-MODY mutants, four of five GK-PHHI mutants had similar specific activity to wild type and Y214C had higher activity than wild type. The GK-binding protein PFK2/FBPase2 protected wild-type GK from oxidative inactivation and the decreased stability of GK-MODY mutants correlated with decreased interaction with PFK2/FBPase2. Several GK-MODY mutants show posttranslational defects in β-cells characterized by increased susceptibility to oxidative stress and/or protein instability. Regulation of GK activity through modulation of thiol status may be a physiological regulatory mechanism for the control of GK activity in β-cells.

Lipase inactivation in wheat germ by gamma irradiation

International Nuclear Information System (INIS)

Jha, Pankaj Kumar; Kudachikar, V.B.; Kumar, Sourav

2013-01-01

An attempt was made to improve the shelf life of wheat germ by optimizing processing conditions involving γ-irradiation. Studies were carried out to investigate the effect of γ-irradiation (0–30 kGy doses) on the chemical composition of wheat germ with respect to variation in moisture, total ash, crude fat, free fatty acid, protein and lipase activity. The results demonstrate that shelf stability of wheat germ was achieved by inactivation of lipase at doses of γ-irradiation greater than 12 kGy. - Highlights: Ø γ-irradiation was found to inactivate Lipase present in Wheat Germ. Ø The treatment did not result in significant changes in Total Ash, Moisture and Protein Content of Wheat Germ. Ø The irradiation at 30 kGy resulted in 31.2 % inactivation of Lipase in Wheat Germ

The pulsed light inactivation of veterinary relevant microbial biofilms ...

African Journals Online (AJOL)

Results show that both Cryptosporidium and Giardia attach to biofilms in large numbers (100-1000 oo/cysts) in as little as 72 hours. Pulsed light successfully inactivated all test species (Listeria, Salmonella, Bacillus, Escherichia) in planktonic and biofilm form with an increase in inactivation for every increase in UV dose.

Peracetic Acid Treatment Generates Potent Inactivated Oral Vaccines from a Broad Range of Culturable Bacterial Species

Science.gov (United States)

Moor, Kathrin; Wotzka, Sandra Y.; Toska, Albulena; Diard, Médéric; Hapfelmeier, Siegfried; Slack, Emma

2016-01-01

Our mucosal surfaces are the main sites of non-vector-borne pathogen entry, as well as the main interface with our commensal microbiota. We are still only beginning to understand how mucosal adaptive immunity interacts with commensal and pathogenic microbes to influence factors such as infectivity, phenotypic diversity, and within-host evolution. This is in part due to difficulties in generating specific mucosal adaptive immune responses without disrupting the mucosal microbial ecosystem itself. Here, we present a very simple tool to generate inactivated mucosal vaccines from a broad range of culturable bacteria. Oral gavage of 1010 peracetic acid-inactivated bacteria induces high-titer-specific intestinal IgA in the absence of any measurable inflammation or species invasion. As a proof of principle, we demonstrate that this technique is sufficient to provide fully protective immunity in the murine model of invasive non-typhoidal Salmonellosis, even in the face of severe innate immune deficiency. PMID:26904024

Capsid protein oxidation in feline calicivirus using an electrochemical inactivation treatment

Energy Technology Data Exchange (ETDEWEB)

Shionoiri, Nozomi; Nogariya, Osamu; Tanaka, Masayoshi; Matsunaga, Tadashi; Tanaka, Tsuyoshi, E-mail: tsuyo@cc.tuat.ac.jp

2015-02-11

Highlights: • Feline calicivirus was inactivated electrochemically by a factor of >5 log. • The electrochemical treatment was performed at 0.9 V (vs. Ag/AgCl) for 15 min. • Electrochemical treatment caused oxidation of viral proteins. • Oxidation of viral proteins can lead to loss of viral structural integrity. - Abstract: Pathogenic viral infections are an international public health concern, and viral disinfection has received increasing attention. Electrochemical treatment has been used for treatment of water contaminated by bacteria for several decades, and although in recent years several reports have investigated viral inactivation kinetics, the mode of action of viral inactivation by electrochemical treatment remains unclear. Here, we demonstrated the inactivation of feline calicivirus (FCV), a surrogate for human noroviruses, by electrochemical treatment in a developed flow-cell equipped with a screen-printed electrode. The viral infectivity titer was reduced by over 5 orders of magnitude after 15 min of treatment at 0.9 V vs. Ag/AgCl. Proteomic study of electrochemically inactivated virus revealed oxidation of peptides located in the viral particles; oxidation was not observed in the non-treated sample. Furthermore, transmission electron microscopy revealed that viral particles in the treated sample had irregular structures. These results suggest that electrochemical treatment inactivates FCV via oxidation of peptides in the structural region, causing structural deformation of virus particles. This first report of viral protein damage through electrochemical treatment will contribute to broadening the understanding of viral inactivation mechanisms.

Effective immunotherapy of weakly immunogenic solid tumours using a combined immunogene therapy and regulatory T-cell inactivation.

LENUS (Irish Health Repository)

Whelan, M C

2012-01-31

Obstacles to effective immunotherapeutic anti-cancer approaches include poor immunogenicity of the tumour cells and the presence of tolerogenic mechanisms in the tumour microenvironment. We report an effective immune-based treatment of weakly immunogenic, growing solid tumours using a locally delivered immunogene therapy to promote development of immune effector responses in the tumour microenvironment and a systemic based T regulatory cell (Treg) inactivation strategy to potentiate these responses by elimination of tolerogenic or immune suppressor influences. As the JBS fibrosarcoma is weakly immunogenic and accumulates Treg in its microenvironment with progressive growth, we used this tumour model to test our combined immunotherapies. Plasmids encoding GM-CSF and B7-1 were electrically delivered into 100 mm(3) tumours; Treg inactivation was accomplished by systemic administration of anti-CD25 antibody (Ab). Using this approach, we found that complete elimination of tumours was achieved at a level of 60% by immunogene therapy, 25% for Treg inactivation and 90% for combined therapies. Moreover, we found that these responses were immune transferable, systemic, tumour specific and durable. Combined gene-based immune effector therapy and Treg inactivation represents an effective treatment for weakly antigenic solid growing tumours and that could be considered for clinical development.

Inactivation of Heterosigma akashiwo in ballast water by circular orifice plate-generated hydrodynamic cavitation.

Science.gov (United States)

Feng, Daolun; Zhao, Jie; Liu, Tian

2016-01-01

The discharge of alien ballast water is a well-known, major reason for marine species invasion. Here, circular orifice plate-generated hydrodynamic cavitation was used to inactivate Heterosigma akashiwo in ballast water. In comparison with single- and multihole orifice plates, the conical-hole orifice plate yielded the highest inactivation percentage, 51.12%, and consumed only 6.84% energy (based on a 50% inactivation percentage). Repeating treatment, either using double series-connection or circling inactivation, elevated the inactivation percentage, yet consumed much more energy. The results indicate that conical-hole-generated hydrodynamic cavitation shows great potential as a pre-inactivation method for ballast water treatment.

Factors affecting the In Vitro inactivation of adolase by x-rays

Energy Technology Data Exchange (ETDEWEB)

Quintiliani, M.; Boccacci, M.

1962-08-15

The influence of urea and of various protective compounds on the in vitro inactivation of aldolase by x rays was studied. Low concentrations of urea protect the enzyme from the inactivation, whereas high concentrations, able to induce an unfolding of the protein molecule, increase the degree inactivation by a given dose of radiation. Cysteamine, cystamine, aminoethyl-isothio-uronium, and glutathione, all protect the aldolase in solution from the inactivation by x rays. Cystamine is as protective as cysteamine, in equimolecular concentrations, when high inactivation levels are reached. No protection can be demonstrated when the aldolase, after incubation with the tested compounds, is precipitated and redissolved in a new medium before irradiation. Nevertheless, with S/sup 35/ labeled cystamine, it can be demonstrated that at least seven residues of cysteamine are bound to each aldolase molecule. The protective power of glutathione is reduced by a factor of about 0.2 in the presence of 4 M urea. The possible implications of these findings are discussed. (auth)

Mechanistic and kinetic aspects of microbial inactivation in food irradiation processes

International Nuclear Information System (INIS)

Tukenmez, I.

2004-01-01

Full text: A proper reaction mechanism was searched by analyzing the inactivation processes of microorganisms during food irradiation by ionizing radiation. By employing transition-state theory, it was assumed that the overall inactivation process involves a reversible sub-lethal stress and repair reactions to form reversibly injured cell or sensitized cell, which then undergoes irreversible injury leading to dead cell. A shoulder in low dose range in survival kinetics was associated with the repair process. Depending on the postulated mechanism, kinetic model equations were derived. The kinetics of cell inactivation by irradiation was expressed as depending on irradiation dose. By using experimental data in the developed model the inactivation parameters including threshold dose, radiation yield, decimal reduction dose and minimum sterilization dose were evaluated and microbial inactivation by irradiation was simulated by using the numerical values of the parameters. Developed model and model parameters may be used for the process control and the assessment of product quality in radiation preservation of food

A molecular switch driving inactivation in the cardiac K+ channel HERG.

Directory of Open Access Journals (Sweden)

David A Köpfer

Full Text Available K(+ channels control transmembrane action potentials by gating open or closed in response to external stimuli. Inactivation gating, involving a conformational change at the K(+ selectivity filter, has recently been recognized as a major K(+ channel regulatory mechanism. In the K(+ channel hERG, inactivation controls the length of the human cardiac action potential. Mutations impairing hERG inactivation cause life-threatening cardiac arrhythmia, which also occur as undesired side effects of drugs. In this paper, we report atomistic molecular dynamics simulations, complemented by mutational and electrophysiological studies, which suggest that the selectivity filter adopts a collapsed conformation in the inactivated state of hERG. The selectivity filter is gated by an intricate hydrogen bond network around residues S620 and N629. Mutations of this hydrogen bond network are shown to cause inactivation deficiency in electrophysiological measurements. In addition, drug-related conformational changes around the central cavity and pore helix provide a functional mechanism for newly discovered hERG activators.

Comparison of glycerolisation with cryopreservation methods on HIV-1 inactivation

International Nuclear Information System (INIS)

Van Baare, J.; Pagnon, J.; Cameron, P.; Vardaxis, N.; Middlekoop, E.; Crowe, S.

1999-01-01

Cryopreservation and glycerolisation are two successful long-term preservation methods for human cadaveric donor skin, which is used in the treatment of bum patients. High concentrations of glycerol has been shown to be antibacterial and virucidal. Because fear of possible transmission of HIV-1 following allograft transplantation, this study was undertaken to investigate whether HIV can be effectively eliminated from skin explants. HIV-1 Ba-L, which has been shown to infect monocytes in skin explants and also dendritic cells, was. For the experiments we used cell-free virus, exogenously HIV infected peripheral blood mononuclear cells (PBMCs) and exogenously HIV infected cadaver split skin. Different concentrations of glycerol at various temperatures and the glycerolisation procedure as used by the Euro Skin Bank were used to determine the effects on HIV-1 Ba-L infectivity. For the cryopreservation technique we used 10% DMSO and a controlled rate freezer. HIV-1 Ba-L transfer was determined by adding uninfected PBMCs to the infected material and reverse transcriptase was measured. Cell-free HIV-1 Ba-L was not inactivated by 50% glycerol but was effectively inactivated within 30 minutes by 70% and 85% glycerol at 4 degree C, room temperature and 37 degree C. In contrast, cell-free HIV-1 Ba-L was not inactivated by cryopreservation. Most importantly, we have shown that HIV-1 Ba-L present in split skin is inactivated by incubating skin in 70% glycerol for three hours at 37-C. HIV in exogenously infected skin was not inactivated by cryopreservation. High concentrations of glycerol effectively inactivates free HIV-1 Ba-L and intracellular HIV-1 Ba-L. Also the current glycerolisation procedure carried out by the Euro Skin Bank effectively inactivates infectious virus. However, the cryopreservation technique did not show any reduction in HIV-1 Ba-L infectivity

Optimising the inactivation of grape juice spoilage organisms by pulse electric fields.

Science.gov (United States)

Marsellés-Fontanet, A Robert; Puig, Anna; Olmos, Paola; Mínguez-Sanz, Santiago; Martín-Belloso, Olga

2009-04-15

The effect of some pulsed electric field (PEF) processing parameters (electric field strength, pulse frequency and treatment time), on a mixture of microorganisms (Kloeckera apiculata, Saccharomyces cerevisiae, Lactobacillus plantarum, Lactobacillus hilgardii and Gluconobacter oxydans) typically present in grape juice and wine were evaluated. An experimental design based on response surface methodology (RSM) was used and results were also compared with those of a factorially designed experiment. The relationship between the levels of inactivation of microorganisms and the energy applied to the grape juice was analysed. Yeast and bacteria were inactivated by the PEF treatments, with reductions that ranged from 2.24 to 3.94 log units. All PEF parameters affected microbial inactivation. Optimal inactivation of the mixture of spoilage microorganisms was predicted by the RSM models at 35.0 kV cm(-1) with 303 Hz pulse width for 1 ms. Inactivation was greater for yeasts than for bacteria, as was predicted by the RSM. The maximum efficacy of the PEF treatment for inactivation of microorganisms in grape juice was observed around 1500 MJ L(-1) for all the microorganisms investigated. The RSM could be used in the fruit juice industry to optimise the inactivation of spoilage microorganisms by PEF.

Inactivation of Adenovirus Type 5, Rotavirus WA and Male Specific Coliphage (MS2 in Biosolids by Lime Stabilization

Directory of Open Access Journals (Sweden)

Aaron B. Margolin

2007-03-01

Full Text Available The use of lime to reduce or eliminate pathogen content is a cost-effective treatment currently employed in many Class B biosolids production plants in the United States. A bench scale model of lime stabilization was designed to evaluate the survival of adenovirus type 5, rotavirus Wa, and the male specific bacteriophage, MS2, in various matrices. Each virus was initially evaluated independently in a reverse osmosis treated water matrix limed with an aqueous solution of calcium hydroxide for 24-hr at 22 ± 5°C. In all R/O water trials, adenovirus type 5, rotavirus Wa and MS2 were below detectable levels (<100.5 TCID50/mL and <1 PFU/mL respectively following 0.1-hr of liming. Adenovirus type 5, rotavirus Wa, and MS2, were inoculated into composted, raw and previously limed matrices, representative of sludge and biosolids, to achieve a final concentration of approximately 104 PFU or TCID50/mL. Each matrix was limed for 24-hr at 22 ± 5°C and 4 ± 2°C. In all trials virus was below detectable levels following a 24-hr incubation. The time required for viral inactivation varied depending on the temperature and sample matrix. This research demonstrates reduction of adenovirus type 5, rotavirus Wa, and male-specific bacteriophage, in water, sludge and biosolids matrices following addition of an 8% calcium hydroxide slurry to achieve a pH of 12 for 2-hr reduced to 11.5 for 22-hr by addition of 0.1 N HCl. In these trials, MS2 was a conservative indicator of the efficacy of lime stabilization of adenovirus Type 5 and rotavirus Wa and therefore is proposed as a useful indicator organism.

Epigenetic inactivation of CHFR in human tumors.

Science.gov (United States)

Toyota, Minoru; Sasaki, Yasushi; Satoh, Ayumi; Ogi, Kazuhiro; Kikuchi, Takefumi; Suzuki, Hiromu; Mita, Hiroaki; Tanaka, Nobuyuki; Itoh, Fumio; Issa, Jean-Pierre J; Jair, Kam-Wing; Schuebel, Kornel E; Imai, Kohzoh; Tokino, Takashi

2003-06-24

Cell-cycle checkpoints controlling the orderly progression through mitosis are frequently disrupted in human cancers. One such checkpoint, entry into metaphase, is regulated by the CHFR gene encoding a protein possessing forkhead-associated and RING finger domains as well as ubiquitin-ligase activity. Although defects in this checkpoint have been described, the molecular basis and prevalence of CHFR inactivation in human tumors are still not fully understood. To address this question, we analyzed the pattern of CHFR expression in a number of human cancer cell lines and primary tumors. We found CpG methylation-dependent silencing of CHFR expression in 45% of cancer cell lines, 40% of primary colorectal cancers, 53% of colorectal adenomas, and 30% of primary head and neck cancers. Expression of CHFR was precisely correlated with both CpG methylation and deacetylation of histones H3 and H4 in the CpG-rich regulatory region. Moreover, CpG methylation and thus silencing of CHFR depended on the activities of two DNA methyltransferases, DNMT1 and DNMT3b, as their genetic inactivation restored CHFR expression. Finally, cells with CHFR methylation had an intrinsically high mitotic index when treated with microtubule inhibitor. This means that cells in which CHFR was epigenetically inactivated constitute loss-of-function alleles for mitotic checkpoint control. Taken together, these findings shed light on a pathway by which mitotic checkpoint is bypassed in cancer cells and suggest that inactivation of checkpoint genes is much more widespread than previously suspected.

UK-18,892: resistance to modification by aminoglycoside-inactivating enzymes.

Science.gov (United States)

Andrews, R J; Brammer, K W; Cheeseman, H E; Jevons, S

1978-12-01

UK-18,892, a new semisynthetic aminoglycoside, was active against bacteria possessing aminoglycoside-inactivating enzymes, with the exception of some known to possess AAC(6') or AAD(4') enzymes. This activity has been rationalized by using cell-free extracts of bacteria containing known inactivating enzymes, where it was shown that UK-18,892 was not a substrate for the APH(3'), AAD(2''), AAC(3), and AAC(2') enzymes. It was also demonstrated that UK-18,892 protected mice against lethal infections caused by organisms possessing aminoglycoside-inactivating enzymes.

Detection of Avian Antigen-Specific T Cells Induced by Viral Vaccines

DEFF Research Database (Denmark)

Dalgaard, Tina Sørensen; Norup, Liselotte Rothmann; Juul-Madsen, Helle Risdahl

2016-01-01

Live attenuated viral vaccines are widely used in commercial poultry production, but the development of new effective inactivated/subunit vaccines is needed. Studies of avian antigen-specific T cells are primarily based on analyses ex vivo after activating the cells with recall antigen. There is ......Live attenuated viral vaccines are widely used in commercial poultry production, but the development of new effective inactivated/subunit vaccines is needed. Studies of avian antigen-specific T cells are primarily based on analyses ex vivo after activating the cells with recall antigen...

Modelling fungal solid-state fermentation: The role of inactivation kinetics

NARCIS (Netherlands)

Smits, J.P.; Sonsbeek, H.M. van; Knol, W.; Tramper, J.; Geelhoed, W.; Peeters, M.; Rinzema, A.

1999-01-01

The theoretical mathematical models described in this paper are used to evaluate the effects of fungal biomass inactivation kinetics on a non- isothermal tray solid-state fermentation (SSF). The inactivation kinetics, derived from previously reported experiments done under isothermal conditions and

Inactivation of carbenicillin by some radioresistant mutant strains

International Nuclear Information System (INIS)

Zahiera, T.S.; Mahmoud, M.I.; Bashandy, A.A.

1990-01-01

Sensitivity test of five bacterial species to carbenicillin was performed microbiologically. The bacterial species were previously isolated from high level radiation environment. All the studied species could either highly decrease the antibiotic activity or even inactivate it completely. Detailed study of the inactivation of carbenicillin by the radioresistant mutant strains B. Laterosporus, B. firmus and M. roseus was performed, in the present study. Using high performace liquid chromatography technique. The gram-positive m. roseus mutant strain seemed to be the most active mutant in degrading the antibiotic. The left over of the antibiotic attained a value of 9% of the original amount after 14 day incubation of the antibiotic with this mutant strain, while the value of the left over reached 36% and 32% after the same period of incubation with the mutants B. laterosporus and B. firmus respectively. In the case of bacillus species, the degradation of the antibiotic started at the same moment when it was added to the bacterial cultures. This fact may indicate that the inactivation of the studied antibiotic by these bacillus species was due to extracellular enzymes extracted rapidly in the surrounding medium. In the case of M. roseus the inactivation process started later. after the addition of the antibiotic to the mutant culture

Alternative inactivated poliovirus vaccines adjuvanted with Quillaja brasiliensis or Quil-a saponins are equally effective in inducing specific immune responses.

Directory of Open Access Journals (Sweden)

Fernanda de Costa

Full Text Available Inactivated polio vaccines (IPV have an important role at the final stages of poliomyelitis eradication programs, reducing the risks associated with the use of attenuated polio vaccine (OPV. An affordable option to enhance vaccine immunogenicity and reduce costs of IPV may be the use of an effective and renewable adjuvant. In the present study, the adjuvant activity of aqueous extract (AE and saponin fraction QB-90 from Quillaja brasiliensis using poliovirus antigen as model were analyzed and compared to a preparation adjuvanted with Quil-A, a well-known saponin-based commercial adjuvant. Experimental vaccines were prepared with viral antigen plus saline (control, Quil-A (50 µg, AE (400 µg or QB-90 (50 µg. Sera from inoculated mice were collected at days 0, 28, 42 and 56 post-inoculation of the first dose of vaccine. Serum levels of specific IgG, IgG1 and IgG2a were significantly enhanced by AE, QB-90 and Quil-A compared to control group on day 56. The magnitude of enhancement was statistically equivalent for QB-90 and Quil-A. The cellular response was evaluated through DTH and analysis of IFN-γ and IL-2 mRNA levels using in vitro reestimulated splenocytes. Results indicated that AE and QB-90 were capable of stimulating the generation of Th1 cells against the administered antigen to the same extent as Quil-A. Mucosal immune response was enhanced by the vaccine adjuvanted with QB-90 as demonstrated by increases of specific IgA titers in bile, feces and vaginal washings, yielding comparable or higher titers than Quil-A. The results obtained indicate that saponins from Q. brasiliensis are potent adjuvants of specific cellular and humoral immune responses and represent a viable option to Quil-A.

37 CFR 11.11 - Administrative suspension, inactivation, resignation, and readmission.

Science.gov (United States)

2010-07-01

... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Administrative suspension, inactivation, resignation, and readmission. 11.11 Section 11.11 Patents, Trademarks, and Copyrights UNITED... Other Non-Patent Law § 11.11 Administrative suspension, inactivation, resignation, and readmission. (a...

Immunogenicity of UV-inactivated measles virus

International Nuclear Information System (INIS)

Zahorska, R.; Mazur, N.; Korbecki, M.

1978-01-01

By means of the antigen extinction limit test it was shown that a triple dose vaccination of guinea pigs with UV-inactivated measles virus gave better results, than a single dose vaccination which was proved by the very low immunogenicity index. For both vaccination schemes (single and triple) the immune response was only sligthly influenced by a change of dose from 10 5 to 10 6 HadU 50 /ml or by the addition of aluminum adjuvant. In the antigen extinction limit test the antibody levels were determined by two methods (HIT and NT) the results of which were statistically equivalent. The UV-inactivated measles virus was also found to induce hemolysis-inhibiting antibodies. (orig.) [de

Influenza (flu) vaccine (Inactivated or Recombinant): What you need to know

Science.gov (United States)

... taken in its entirety from the CDC Inactivated Influenza Vaccine Information Statement (VIS) www.cdc.gov/vaccines/hcp/vis/vis-statements/flu.html CDC review information for Inactivated Influenza VIS: ...

Inactivation disinfection property of Moringa Oleifera seed extract: optimization and kinetic studies

Science.gov (United States)

Idris, M. A.; Jami, M. S.; Hammed, A. M.

2017-05-01

This paper presents the statistical optimization study of disinfection inactivation parameters of defatted Moringa oleifera seed extract on Pseudomonas aeruginosa bacterial cells. Three level factorial design was used to estimate the optimum range and the kinetics of the inactivation process was also carried. The inactivation process involved comparing different disinfection models of Chicks-Watson, Collins-Selleck and Homs models. The results from analysis of variance (ANOVA) of the statistical optimization process revealed that only contact time was significant. The optimum disinfection range of the seed extract was 125 mg/L, 30 minutes and 120rpm agitation. At the optimum dose, the inactivation kinetics followed the Collin-Selleck model with coefficient of determination (R2) of 0.6320. This study is the first of its kind in determining the inactivation kinetics of pseudomonas aeruginosa using the defatted seed extract.

Inactivation Effect of Antibiotic-Resistant Gene Using Chlorine Disinfection

Directory of Open Access Journals (Sweden)

Takashi Furukawa

2017-07-01

Full Text Available The aim of this study was to elucidate the inactivation effects on the antibiotic-resistance gene (vanA of vancomycin-resistant enterococci (VRE using chlorination, a disinfection method widely used in various water treatment facilities. Suspensions of VRE were prepared by adding VRE to phosphate-buffered saline, or the sterilized secondary effluent of a wastewater treatment plant. The inactivation experiments were carried out at several chlorine concentrations and stirring time. Enterococci concentration and presence of vanA were determined. The enterococci concentration decreased as chlorine concentrations and stirring times increased, with more than 7.0 log reduction occurring under the following conditions: 40 min stirring at 0.5 mg Cl2/L, 20 min stirring at 1.0 mg Cl2/L, and 3 min stirring at 3.0 mg Cl2/L. In the inactivation experiment using VRE suspended in secondary effluent, the culturable enterococci required much higher chlorine concentration and longer treatment time for complete disinfection than the cases of suspension of VRE. However, vanA was detected in all chlorinated suspensions of VRE, even in samples where no enterococcal colonies were present on the medium agar plate. The chlorine disinfection was not able to destroy antibiotic-resistance genes, though it can inactivate and decrease bacterial counts of antibiotic-resistant bacteria (ARB. Therefore, it was suggested that remaining ARB and/or antibiotic-resistance gene in inactivated bacterial cells after chlorine disinfection tank could be discharged into water environments.

Radical inactivation of a biological sulphydryl molecule

International Nuclear Information System (INIS)

Lin, W.S.; Lal, M.; Gaucher, G.M.; Armstrong, D.A.

1977-01-01

Reactive species produced from the free radical-induced chain oxidation of low molecular weight sulphydryl-containing molecules in aerated solutions deactivate the sulphydryl-containing enzyme papain, forming both reparable mixed disulphides and non-reparable products. This inactivation is highly efficient for penicillamine and glutathione, but almost negligible with cysteine, which is a protector of papain for [cysteine] / [papain] >= 5 under all conditions used. In the case of glutathione, superoxide dismutase caused only a small reduction in the inactivation and peroxide yields were small, implying that the deactivating species are not .O 2 - but RSOO. radicals or products from them. For penicillamine, however, dimutase was highly effective and the peroxide yields were relatively large, demonstrating that .O 2 - or a radical with similar capabilities for forming H 2 O 2 and being deactivated by dismutase was involved. Although in the presence of dismutase penicillamine is a better protector of non-reparable papain inactivation than glutathione, it suffers from a deficiency in that the papain-penicillamine mixed disulphide, which is always formed, cannot be repaired by spontaneous reaction with RSH molecules. (author)

Multipoint attachment to a support protects enzyme from inactivation by organic solvents: alpha-Chymotrypsin in aqueous solutions of alcohols and diols.

Science.gov (United States)

Mozhaev, V V; Sergeeva, M V; Belova, A B; Khmelnitsky, Y L

1990-03-25

Inactivation of alpha-chymotrypsin in aqueous solutions of alcohols and diols proceeds both reversibly and irreversibly. Reversible loss of the specific enzyme activity results from conformational changes (unfolding) of the enzyme detected by fluorescence spectroscopy. Multipoint covalent attachment to the matrix of polyacryl-amide gel by copolymerization method stabilizes alpha-chymotrypsin from denaturation by alcohols, the stabilizing effect increasing with the number of bonds between the protein and the support. Immobilization protects the enzyme also from irreversible inactivation by organic solvents resulting from bimolecular aggregation and autolysis.

Imprinted X chromosome inactivation: evolution of mechanisms in distantly related mammals

Directory of Open Access Journals (Sweden)

Shafagh A. Waters

2015-03-01

Full Text Available In females, X chromosome inactivation (XCI ensures transcriptional silencing of one of the two Xs (either in a random or imprinted fashion in somatic cells. Comparing this silencing between species has offered insight into different mechanisms of X inactivation, providing clues into the evolution of this epigenetic process in mammals. Long-noncoding RNAs have emerged as a common theme in XCI of therian mammals (eutherian and marsupial. Eutherian X inactivation is regulated by the noncoding RNA product of XIST, within a cis-acting master control region called the X inactivation center (XIC. Marsupials XCI is XIST independent. Instead, XCI is controlled by the long-noncoding RNA Rsx, which appears to be a functional analog of the eutherian XIST gene, insofar that its transcript coats the inactive X and represses activity of genes in cis. In this review we discuss XCI in eutherians, and contrast imprinted X inactivation in mouse and marsupials. We provide particular focus on the evolution of genomic elements that confer the unique epigenetic features that characterize the inactive X chromosome.

Pulsed dielectric barrier discharge for Bacillus subtilis inactivation in water

Science.gov (United States)

Hernández-Arias, A. N.; Rodríguez-Méndez, B. G.; López-Callejas, R.; Valencia-Alvarado, R.; Mercado-Cabrera, A.; Peña-Eguiluz, R.; Barocio, S. R.; Muñoz-Castro, A. E.; de la Piedad Beneitez, A.

2012-06-01

The inactivation of Bacillus subtilis bacteria in water has been experimentally studied by means of a pulsed dielectric barrier discharge (PDBD) in a coaxial reactor endowed with an alumina dielectric. The plasma source is capable of operating at atmospheric pressure with gas, water or hybrid gas-liquid media at adjustable 25 kV pulses, 30 μs long and at a 500 Hz frequency. In order to evaluate the inactivation efficiency of the system, a set of experiments were designed on the basis of oxygen flow control. The initial data have showed a significant bacterial rate reduction of 103-107 CFU/mL. Additional results proved that applying an oxygen flow for a few seconds during the PDBD treatment inactivates the Bacillus subtilis population with 99.99% effectiveness. As a reference, without gas flow but with the same exposure times, this percentage is reduced to ~90%. The analysis of the relationship between inactivation rate and chemical species in the discharge has been carried out using optical emission spectroscopy as to identifying the main reactive species. Reactive oxygen species such as atomic oxygen and ozone tuned out to be the dominant germicidal species. Some proposed inactivation mechanisms of this technique are discussed.

Pulsed dielectric barrier discharge for Bacillus subtilis inactivation in water

International Nuclear Information System (INIS)

Hernández-Arias, A N; López-Callejas, R; De la Piedad Beneitez, A; Rodríguez-Méndez, B G; Valencia-Alvarado, R; Mercado-Cabrera, A; Peña-Eguiluz, R; Barocio, S R; Muñoz-Castro, A E

2012-01-01

The inactivation of Bacillus subtilis bacteria in water has been experimentally studied by means of a pulsed dielectric barrier discharge (PDBD) in a coaxial reactor endowed with an alumina dielectric. The plasma source is capable of operating at atmospheric pressure with gas, water or hybrid gas-liquid media at adjustable 25 kV pulses, 30 μs long and at a 500 Hz frequency. In order to evaluate the inactivation efficiency of the system, a set of experiments were designed on the basis of oxygen flow control. The initial data have showed a significant bacterial rate reduction of 10 3 -10 7 CFU/mL. Additional results proved that applying an oxygen flow for a few seconds during the PDBD treatment inactivates the Bacillus subtilis population with 99.99% effectiveness. As a reference, without gas flow but with the same exposure times, this percentage is reduced to ∼90%. The analysis of the relationship between inactivation rate and chemical species in the discharge has been carried out using optical emission spectroscopy as to identifying the main reactive species. Reactive oxygen species such as atomic oxygen and ozone tuned out to be the dominant germicidal species. Some proposed inactivation mechanisms of this technique are discussed.

EVALUATION OF REACTOGENICITY, SAFETY AND IMMUNOGENICITY OF INACTIVATED MONOVALENT VACCINE IN CHILDREN

OpenAIRE

A.N. Mironov; A.A. Romanova; R.Ya. Meshkova; I.V. Fel’dblyum; N.V. Kupina; D.S. Bushmenkov; A.A. Tsaan

2010-01-01

NPO «Microgen» developed vaccine «PANDEFLU» — influenza inactivated subunit adsorbed monovalent vaccine, strain A/California/7/2009 (H1N1), for specific prophylaxis of pandemic influenza in different age groups of citizens. Reactogenicity, safety and immunogenicity were analyzed in a study of volunteers 18–60 years old. The article presents results of administration of vaccine «PANDEFLU» in children. The study performed in two clinical centers proves good tolerability, reactogenicity, safety ...

Anti-Human Endoglin (hCD105) Immunotoxin-Containing Recombinant Single Chain Ribosome-Inactivating Protein Musarmin 1.

Science.gov (United States)

Barriuso, Begoña; Antolín, Pilar; Arias, F Javier; Girotti, Alessandra; Jiménez, Pilar; Cordoba-Diaz, Manuel; Cordoba-Diaz, Damián; Girbés, Tomás

2016-06-10

Endoglin (CD105) is an accessory component of the TGF-β receptor complex, which is expressed in a number of tissues and over-expressed in the endothelial cells of tumor neovasculature. Targeting endoglin with immunotoxins containing type 2 ribosome-inactivating proteins has proved an effective tool to reduce blood supply to B16 mice tumor xenografts. We prepared anti-endoglin immunotoxin (IT)-containing recombinant musarmin 1 (single chain ribosome-inactivating proteins) linked to the mouse anti-human CD105 44G4 mouse monoclonal antibody via N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP). The immunotoxin specifically killed L929 fibroblast mouse cells transfected with the short form of human endoglin with IC50 values in the range of 5 × 10(-10) to 10(-9) M.

Inactivation of E. Coli in Water Using Photocatalytic, Nanostructured Films Synthesized by Aerosol Routes

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Pratim Biswas

2013-03-01

Full Text Available TiO2 nanostructured films were synthesized by an aerosol chemical vapor deposition (ACVD method with different controlled morphologies: columnar, granular, and branched structures for the photocatalytic inactivation of Escherichia coli (E. coli in water. Effects of film morphology and external applied voltage on inactivation rate were investigated. As-prepared films were characterized using scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffractometry (XRD, and UV-VIS. Photocatalytic and photoelectrochemical inactivation of E. coli using as-prepared TiO2 films were performed under irradiation of UVA light (note: UVA has a low efficiency to inactivate E. coli. Inactivation rate constants for each case were obtained from their respective inactivation curve through a 2 h incubation period. Photocatalytic inactivation rate constants of E. coli are 0.02/min (using columnar films, and 0.08/min (using branched films. The inactivation rate constant for the columnar film was enhanced by 330% by applied voltage on the film while that for the branched film was increased only by 30%. Photocatalytic microbial inactivation rate of the columnar and the branched films were also compared taking into account their different surface areas. Since the majority of the UV radiation that reaches the Earth’s surface is UVA, this study provides an opportunity to use sunlight to efficiently decontaminate drinking water.

Stem-Cell Inactivation on Transplantation of Haemopoietic Cell Suspensions from Genetically Different Donors

Energy Technology Data Exchange (ETDEWEB)

Petrov, R. V. [Institute of Biophysics, Ministry of Public Health of the USSR, Moscow, USSR (Russian Federation)

1969-07-15

The transplantation of a mixture of haemopoietic or lymphoid cells from two genetically different mice into lethally irradiated F{sub 1} recipients results in marked or total inactivation of the colony-forming units of the graft. This phenomenon is observed following transplantation of mixtures of spleen cells or bone-marrow cells from animals of different genotypes: CBA + C57BL, A + CBA, A + C57BL, C3H + C57BL, CBA + (CBA x C57BL) F{sub 1}. Maximum inactivation is observed when lymph-node cells of one genotype are transplanted with spleen or bone-marrow cells of another genotype. Use of non-syngenic kidney cells or lymphoid cells inactivated by irradiation as one component of the mixture shows that inactivation of genetically heterogeneous stem cells requires the participation of viable lymphoid cells. The inactivation phenomenon is also observed with Jerne's method. This shows that inactivation affects not only colony-forming cells but also the immunologically competent precursors of antibody-producing cells. (author)

Inactivation of influenza A virus H1N1 by disinfection process.

Science.gov (United States)

Jeong, Eun Kyo; Bae, Jung Eun; Kim, In Seop

2010-06-01

Because any patient, health care worker, or visitor is capable of transmitting influenza to susceptible persons within hospitals, hospital-acquired influenza has been a clinical concern. Disinfection and cleaning of medical equipment, surgical instruments, and hospital environment are important measures to prevent transmission of influenza virus from hospitals to individuals. This study was conducted to evaluate the efficacy of disinfection processes, which can be easily operated at hospitals, in inactivating influenza A virus H1N1 (H1N1). The effects of 0.1 mol/L NaOH, 70% ethanol, 70% 1-propanol, solvent/detergent (S/D) using 0.3% tri (n-butyl)-phosphate and 1.0% Triton X-100, heat, and ethylene oxide (EO) treatments in inactivating H1N1 were determined. Inactivation of H1N1 was kinetically determined by the treatment of disinfectants to virus solution. Also, a surface test method, which involved drying an amount of virus on a surface and then applying the inactivation methods for 1 minute of contact time, was used to determine the virucidal activity. H1N1 was completely inactivated to undetectable levels in 1 minute of 70% ethanol, 70% 1-propanol, and solvent/detergent treatments in the surface tests as well as in the suspension tests. H1N1 was completely inactivated in 1 minute of 0.1 mol/L NaOH treatment in the suspension tests and also effectively inactivated in the surface tests with the log reduction factor of 3.7. H1N1 was inactivated to undetectable levels within 5 minutes, 2.5 minutes, and 1 minute of heat treatment at 70, 80, and 90 degrees C, respectively in the suspension tests. Also, H1N1 was completely inactivated by EO treatment in the surface tests. Common disinfectants, heat, and EO tested in this study were effective at inactivating H1N1. These results would be helpful in implementing effective disinfecting measures to prevent hospital-acquired infections. Copyright 2010 Association for Professionals in Infection Control and Epidemiology, Inc

The Eag domain regulates the voltage-dependent inactivation of rat Eag1 K+ channels.

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Ting-Feng Lin

Full Text Available Eag (Kv10 and Erg (Kv11 belong to two distinct subfamilies of the ether-à-go-go K+ channel family (KCNH. While Erg channels are characterized by an inward-rectifying current-voltage relationship that results from a C-type inactivation, mammalian Eag channels display little or no voltage-dependent inactivation. Although the amino (N-terminal region such as the eag domain is not required for the C-type inactivation of Erg channels, an N-terminal deletion in mouse Eag1 has been shown to produce a voltage-dependent inactivation. To further discern the role of the eag domain in the inactivation of Eag1 channels, we generated N-terminal chimeras between rat Eag (rEag1 and human Erg (hERG1 channels that involved swapping the eag domain alone or the complete cytoplasmic N-terminal region. Functional analyses indicated that introduction of the homologous hERG1 eag domain led to both a fast phase and a slow phase of channel inactivation in the rEag1 chimeras. By contrast, the inactivation features were retained in the reverse hERG1 chimeras. Furthermore, an eag domain-lacking rEag1 deletion mutant also showed the fast phase of inactivation that was notably attenuated upon co-expression with the rEag1 eag domain fragment, but not with the hERG1 eag domain fragment. Additionally, we have identified a point mutation in the S4-S5 linker region of rEag1 that resulted in a similar inactivation phenotype. Biophysical analyses of these mutant constructs suggested that the inactivation gating of rEag1 was distinctly different from that of hERG1. Overall, our findings are consistent with the notion that the eag domain plays a critical role in regulating the inactivation gating of rEag1. We propose that the eag domain may destabilize or mask an inherent voltage-dependent inactivation of rEag1 K+ channels.

Turnover-dependent inactivation of the nitrogenase MoFe-protein at high pH.

Science.gov (United States)

Yang, Kun-Yun; Haynes, Chad A; Spatzal, Thomas; Rees, Douglas C; Howard, James B

2014-01-21

Proton uptake accompanies the reduction of all known substrates by nitrogenase. As a consequence, a higher pH should limit the availability of protons as a substrate essential for turnover, thereby increasing the proportion of more highly reduced forms of the enzyme for further study. The utility of the high-pH approach would appear to be problematic in view of the observation reported by Pham and Burgess [(1993) Biochemistry 32, 13725-13731] that the MoFe-protein undergoes irreversible protein denaturation above pH 8.65. In contrast, we found by both enzyme activity and crystallographic analyses that the MoFe-protein is stable when incubated at pH 9.5. We did observe, however, that at higher pHs and under turnover conditions, the MoFe-protein is slowly inactivated. While a normal, albeit low, level of substrate reduction occurs under these conditions, the MoFe-protein undergoes a complex transformation; initially, the enzyme is reversibly inhibited for substrate reduction at pH 9.5, yet in a second, slower process, the MoFe-protein becomes irreversibly inactivated as measured by substrate reduction activity at the optimal pH of 7.8. The final inactivated MoFe-protein has an increased hydrodynamic radius compared to that of the native MoFe-protein, yet it has a full complement of iron and molybdenum. Significantly, the modified MoFe-protein retains the ability to specifically interact with its nitrogenase partner, the Fe-protein, as judged by the support of ATP hydrolysis and by formation of a tight complex with the Fe-protein in the presence of ATP and aluminum fluoride. The turnover-dependent inactivation coupled to conformational change suggests a mechanism-based transformation that may provide a new probe of nitrogenase catalysis.

Studies on disappearance and inactivation of viruses in sewage, 2

International Nuclear Information System (INIS)

Yano, Kazuyoshi; Yabuuchi, Kiyoshi; Taguchi, Fumiaki.

1985-01-01

Methods of inactivating viruses in wastewater were studied. Polio visuses were added to the distilled water until the number of viruses reached 10sup(6.8) TCID 50 /ml, and liquid layer was 2 mm. The inactivation rate of viruses was determined at each time of ultraviolet (U.V.) irradiation (from 0.425 x 10 4 μw/cm 2 to 10.0 x 10 4 μw/cm 2 ). A linear correlation was seen between the inactivation rate of viruses and the time of U.V. irradiation obtained from logarithmic transformation. The irradiation time required for inactivation of 99.9% viruses was 15 sec when U.V. intensity was 10.0 x 10 4 μw/cm 2 and 9.6 min when it was 0.423 x 10 4 μw/cm 2 . When the U.V. intensity was 0.425 x 10 4 μw/cm 2 , the time required for inactivation was dependent on the number of viruses (120 sec in cases of 10sup(3.8) TCID 50 /ml of viruses and 720 sec in cases of 10sup(7.8) TCID 50 /ml of viruses). When viruses were added to the distilled water until the number reached 10sup(5.8) TCID 50 /ml, and the depth of water was designated as 2 mm, 10 cm, and 15 cm, the U.V. permeability was more than 89% at any depth of water, and a sixteen-min U.V. irradiation inactivated more than 99.99% of viruses. When polio viruses were added to triple step-treated water until the number reached 10sup(5.3) TCID 50 /ml, the irradiation time required for inactivation of more than 99.99% was one min when the U.V. intensity was 10.0 x 10 4 μw/cm 2 and 20 min when it was 0.425 x 10 4 μw/cm 2 . (Namekawa, K.)

Efficient Bacteria Inactivation by Ultrasound in Municipal Wastewater

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Leonel Ernesto Amabilis-Sosa

2018-04-01

Full Text Available The reuse of treated wastewaters could contribute to reducing water stress. In this research, ultrasound application on bacterial inactivation in municipal wastewater (MWW was evaluated. Total and fecal coliforms were used as standard fecal indicators; volatile suspended solids (VSS were analyzed too. Samples were taken from the effluent of secondary clarifiers. In addition, inactivation tests were carried out on pure cultures of E. coli (EC and B. subtilis (BS. Sonication was performed at 20 kHz, 35% amplitude and 600 W/L for 15, 30 and 45 min. After 15 min of sonication, bacterial density was reduced by 1.85 Log10 MPN/100 mL for EC and 3.16 Log10 CFU/mL for BS. After 30 min, no CFU/mL of BS were observed in MWW and, after 45 min, the reduction of total and fecal coliforms was practically 6.45 Log10 MPN/100mL. Inactivation mechanism was made by cavitation, which causes irreversible damage to the cell wall. Although high bacterial densities were employed, percentages of inactivation >99% were reached at 45 min. This research contributes to the implementation of ultrasound as a disinfection technique with high potential due to its high efficiency without producing byproducts. In fact, the water meets the guidelines for reuse in direct human contact services.

Does oxygen enhance the radiation: induced inactivation of penicillinase. Progress report, December 1, 1979-November 30, 1980

International Nuclear Information System (INIS)

Samuni, A.; Kalkstein, A.; Czapski, G.

1980-01-01

The radiation-induced inactivation of penicillinase in dilute aqueous solutions buffered with phosphate was studied, by examining enzyme radiosensitivity in the presence of various gases (He, O 2 , H 2 , N 2 O, N 2 O + O 2 ). The introduction of either N 2 O or O 2 was found to reduce the radiodamage. On the other hand H 2 or N 2 O + O 2 gas-mixture enhanced the radiosensitivity. In the presence of formate and oxygen, no enzyme inactivation was detected. The results indicated that the specific damaging efficiency of H atoms is almost four-fold higher than that of OH radical; therefore in phosphate buffer, where more than half of the free radicals are H atoms, it is the H radicals that are responsible for the majority of the damage. The superoxide radicals appeared to be completely inactive and did not contribute toward enzyme inactivation. Oxygen was shown to affect the radiosensitivity in two ways. On one side, it protected by converting e - /sub aq/ and H radicals into harmless O 2 - radicals. On the other side it increased the inactivation by enhancing the damage brought about by OH radicals (OER = 2.8). In the present case the oxygen effect of protection exceeded that of sensitization, thus giving rise to a moderate overall protection effect

Inactivation of bacteria in sewage sludge by gamma radiation

International Nuclear Information System (INIS)

Pandya, G.A.; Kapila, Smita; Kelkar, V.B.; Negi, Shobha; Modi, V.V.

1987-01-01

The survival of certain bacterial cultures suspended in sewage sludge and exposed to gamma-radiation was studied. The inactivation patterns of most of the organisms were significantly different when irradiation was performed using sewage samples collected in the summer and monsoon seasons. The summer sample collected from the anaerobic digester afforded significant protection to both Gram negative and Gram positive organisms. This was evident by the increase in dose required to bring about a 6 log cycle reduction in viable count of the bacterial cultures, when suspended in sewage samples instead of phosphate buffer. The observations made using monsoon digester samples were quite different. This sewage sludge greatly enhanced inactivation by gamma-radiation in most cases. The effects of certain chemicals on the inactivation patterns of two organisms - Salmonella typhi and Shigella flexneri - were examined. Arsenate, mercury and lead salts sensitised S. typhi, while barium acetate and sodium sulphide protected this culture against gamma-radiation. In the case of Sh. flexneri, barium acetate and iodacetamide proved to be radioprotectors. The effects of some chemicals on the inactivation pattern of Sh. flexneri cells irradiated in sludge are also discussed. (author)

Synthesis and characterization of PLGA nanoparticles containing mixture of curcuminoids for optimization of photodynamic inactivation

Science.gov (United States)

Suzuki, Isabella L.; Inada, Natália M.; Marangoni, Valéria S.; Corrêa, Thaila Q.; Zucolotto, Valtencir; Kurachi, Cristina; Bagnato, Vanderlei S.

2016-03-01

Because of excessive use of antibiotics there is a growth in the number of resistant strains. Due to this growth of multiresistant bacteria, the number of searches looking for alternatives antibacterial therapeutic has increased, and among them is the antimicrobial photodynamic therapy (aPDT) or photodynamic inactivation (PDI). The photodynamic inactivation involves the action of a photosensitizer (PS), activated by a specific wavelength, in the present of oxygen, resulting in cytotoxic effect. Natural curcumin, consists of a mixture of three curcuminoids: curcumin, demethoxycurcumin and bis-demethoxycurcumin. Curcumin has various pharmacological properties, however, has extremely low solubility in aqueous solutions, which difficult the use as therapeutic agent. The present study aims to develop polymeric PLGA nanoparticles containing curcuminoids to improve water solubility, increase bioavailability providing protection from degradation (chemistry and physics), and to verify the efficacy in photodynamic inactivation of microorganisms. The PLGA-CURC were synthesized by nanoprecipitation, resulting in two different systems, with an average size of 172 nm and 70% encapsulation efficiency for PLGA-CURC1, and 215 nm and 80% for PLGA-CURC2. Stability tests showed the polymer protected the curcuminoids against premature degradation. Microbiological tests in vitro with curcuminoids water solution and both suspension of PLGA-CURC were efficient in Gram-positive bacterium and fungus. However, the solution presented dark toxicity at high concentrations, unlike the nanoparticles. Thus, it was concluded that it was possible to let curcuminoids water soluble by encapsulation in PLGA nanoparticles, to ensure improved stability in aqueous medium (storage), and to inactivate bacteria and fungus.

Nanoscale Structural and Mechanical Analysis of Bacillus anthracis Spores Inactivated with Rapid Dry Heating

Science.gov (United States)

Felker, Daniel L.; Burggraf, Larry W.

2014-01-01

Effective killing of Bacillus anthracis spores is of paramount importance to antibioterrorism, food safety, environmental protection, and the medical device industry. Thus, a deeper understanding of the mechanisms of spore resistance and inactivation is highly desired for developing new strategies or improving the known methods for spore destruction. Previous studies have shown that spore inactivation mechanisms differ considerably depending upon the killing agents, such as heat (wet heat, dry heat), UV, ionizing radiation, and chemicals. It is believed that wet heat kills spores by inactivating critical enzymes, while dry heat kills spores by damaging their DNA. Many studies have focused on the biochemical aspects of spore inactivation by dry heat; few have investigated structural damages and changes in spore mechanical properties. In this study, we have inactivated Bacillus anthracis spores with rapid dry heating and performed nanoscale topographical and mechanical analysis of inactivated spores using atomic force microscopy (AFM). Our results revealed significant changes in spore morphology and nanomechanical properties after heat inactivation. In addition, we also found that these changes were different under different heating conditions that produced similar inactivation probabilities (high temperature for short exposure time versus low temperature for long exposure time). We attributed the differences to the differential thermal and mechanical stresses in the spore. The buildup of internal thermal and mechanical stresses may become prominent only in ultrafast, high-temperature heat inactivation when the experimental timescale is too short for heat-generated vapor to efficiently escape from the spore. Our results thus provide direct, visual evidences of the importance of thermal stresses and heat and mass transfer to spore inactivation by very rapid dry heating. PMID:24375142

Use of In Situ-Generated Dimethyldioxirane for Inactivation of Biological Agents

National Research Council Canada - National Science Library

Wallace, William H; Bushway, Karen E; Miller, Susan D; Delcomyn, Carrie A; Renard, Jean J; Henley, Michael V

2005-01-01

...) at neutral pH, was investigated for inactivation of biological warfare agent simulants. The DMDO solution inactivated bacterial spores, fungal spores, vegetative bacterial cells, viruses, and protein by 7 orders of magnitude in less than 10 min...

High pressure processing's potential to inactivate norovirus and other fooodborne viruses

Science.gov (United States)

High pressure processing (HPP) can inactivate human norovirus. However, all viruses are not equally susceptible to HPP. Pressure treatment parameters such as required pressure levels, initial pressurization temperatures, and pressurization times substantially affect inactivation. How food matrix ...

Method of inactivating reproducible forms of mycoplasma in biological preparations

International Nuclear Information System (INIS)

Veber, P.; Jurmanova, K.; Lesko, J.; Hana, L.; Veber, V.

1978-01-01

Inactivation of mycoplasms in biological materials was achieved using gamma radiation with a dose rate of 1x10 4 to 5x10 6 rads/h for 1 to 250 hours. The technique is advantageous for allowing the inactivation of the final form of products (tablets, vaccines, etc.). (J.P.)

Chlorine inactivation of fungal spores on cereal grains.

Science.gov (United States)

Andrews, S; Pardoel, D; Harun, A; Treloar, T

1997-04-01

Although 0.4% chlorine for 2 min has been recommended for surface disinfection of food samples before direct plating for fungal enumeration, this procedure may not be adequate for highly contaminated products. The effectiveness of a range of chlorine solutions was investigated using barley samples artificially contaminated with four different concentrations of Aspergillus flavus. A. niger, A. ochraceus, Eurotium repens, Penicillium brevicompactum P. chrysogenum and Cladosporium cladosporioides. At initial contamination levels greater than 10(4)/g, 0.4% chlorine did not inactivate sufficient spores to produce less than 20% contamination. Of the test fungi, ascospores of E. repens were the most resistant to chlorine inactivation, whereas the conidia of C. cladosporioides were the most sensitive. Rinsing the samples with 70% ethanol improved the effectiveness of the recommended surface disinfection procedure. However, some ethanol appears to permeate into the grains and may inactivate sensitive internal fungi, although a minimal effect only was observed on wheat infected with Alternaria.

Inactivation of alcohol dehydrogenase (ADH) by ferryl derivatives of human hemoglobin.

Science.gov (United States)

Kowalczyk, Aleksandra; Puchała, Mieczysław; Wesołowska, Katarzyna; Serafin, Eligiusz

2007-01-01

In this paper, inactivation of alcohol dehydrogenase (ADH) by products of reactions of H2O2 with metHb has been studied. Inactivation of the enzyme was studied in two systems corresponding to two kinetic stages of the reaction. In the first system H2O2 was added to the mixture of metHb and ADH [the (metHb+ADH)+H2O2] system (ADH was present in the system since the moment of addition of H2O2 i. e. since the very beginning of the reaction of metHb with H2O2). In the second system ADH was added to the system 5 min after the initiation of the reaction of H2O2 with metHb [the (metHb+H2O2)5 min+ADH] system. In the first case all the products of reaction of H2O2 with metHb (non-peroxyl and peroxyl radicals and non-radical products, viz. hydroperoxides and *HbFe(IV)=O) could react with the enzyme causing its inactivation. In the second system, enzyme reacted almost exclusively with non-radical products (though a small contribution of reactions with peroxyl radicals cannot be excluded). ADH inactivation was observed in both system. Hydrogen peroxide alone did not inactivate ADH at the concentrations employed evidencing that enzyme inactivation was due exclusively to products of reaction of H2O2 with metHb. The rate and extent of ADH inactivation were much higher in the first than in the second system. The dependence of ADH activity on the time of incubation with ferryl derivatives of Hb can be described by a sum of three exponentials in the first system and two exponentials in the second system. Reactions of appropriate forms of the ferryl derivatives of hemoglobin have been tentatively ascribed to these exponentials. The extent of the enzyme inactivation in the second system was dependent on the proton concentration, being at the highest at pH 7.4 and negligible at pH 6.0. The reaction of H2O2 with metHb resulted in the formation of cross-links of Hb subunits (dimers and trimers). The amount of the dimers formed was much lower in the first system i. e. when the radical

Inactivation of viruses in labile blood derivatives. II. Physical methods

International Nuclear Information System (INIS)

Horowitz, B.; Wiebe, M.E.; Lippin, A.; Vandersande, J.; Stryker, M.H.

1985-01-01

The thermal inactivation of viruses in labile blood derivatives was evaluated by addition of marker viruses (VSV, Sindbis, Sendai, EMC) to anti-hemophilic factor (AHF) concentrates. The rate of virus inactivation at 60 degrees C was decreased by at least 100- to 700-fold by inclusion of 2.75 M glycine and 50 percent sucrose, or 3.0 M potassium citrate, additives which contribute to retention of protein biologic activity. Nonetheless, at least 10(4) infectious units of each virus was inactivated within 10 hours. Increasing the temperature from 60 to 70 or 80 degrees C caused a 90 percent or greater loss in AHF activity. An even greater decline in the rate of virus inactivation was observed on heating AHF in the lyophilized state, although no loss in AHF activity was observed after 72 hours of heating at 60 degrees C. Several of the proteins present in lyophilized AHF concentrates displayed an altered electrophoretic mobility as a result of exposure to 60 degrees C for 24 hours. Exposure of lyophilized AHF to irradiation from a cobalt 60 source resulted in an acceptable yield of AHF at 1.0, but not at 2.0, megarads. At 1 megarad, greater than or equal to 6.0 logs of VSV and 3.3 logs of Sindbis virus were inactivated

Efficiency of superoxide anions in the inactivation of selected dehydrogenases

International Nuclear Information System (INIS)

Rodacka, Aleksandra; Serafin, Eligiusz; Puchala, Mieczyslaw

2010-01-01

The most ubiquitous of the primary reactive oxygen species, formed in all aerobes, is the superoxide free radical. It is believed that the superoxide anion radical shows low reactivity and in oxidative stress it is regarded mainly as an initiator of more reactive species such as · OH and ONOO - . In this paper, the effectiveness of inactivation of selected enzymes by radiation-generated superoxide radicals in comparison with the effectiveness of the other products of water radiolysis is examined. We investigate three enzymes: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH). We show that the direct contribution of the superoxide anion radical to GAPDH and ADH inactivation is significant. The effectiveness of the superoxide anion in the inactivation of GAPDH and ADG was only 2.4 and 2.8 times smaller, respectively, in comparison with hydroxyl radical. LDH was practically not inactivated by the superoxide anion. Despite the fact that the studied dehydrogenases belong to the same class of enzymes (oxidoreductases), all have a similar molecular weight and are tetramers, their susceptibility to free-radical damage varies. The differences in the radiosensitivity of the enzymes are not determined by the basic structural parameters analyzed. A significant role in inactivation susceptibility is played by the type of amino acid residues and their localization within enzyme molecules.

Efficiency of superoxide anions in the inactivation of selected dehydrogenases

Energy Technology Data Exchange (ETDEWEB)

Rodacka, Aleksandra, E-mail: olakow@biol.uni.lodz.p [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, 90-237 Lodz (Poland); Serafin, Eligiusz, E-mail: serafin@biol.uni.lodz.p [Laboratory of Computer and Analytical Techniques, University of Lodz, Banacha 12/16, 90-237 Lodz (Poland); Puchala, Mieczyslaw, E-mail: puchala@biol.uni.lodz.p [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, 90-237 Lodz (Poland)

2010-09-15

The most ubiquitous of the primary reactive oxygen species, formed in all aerobes, is the superoxide free radical. It is believed that the superoxide anion radical shows low reactivity and in oxidative stress it is regarded mainly as an initiator of more reactive species such as {sup {center_dot}}OH and ONOO{sup -}. In this paper, the effectiveness of inactivation of selected enzymes by radiation-generated superoxide radicals in comparison with the effectiveness of the other products of water radiolysis is examined. We investigate three enzymes: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH). We show that the direct contribution of the superoxide anion radical to GAPDH and ADH inactivation is significant. The effectiveness of the superoxide anion in the inactivation of GAPDH and ADG was only 2.4 and 2.8 times smaller, respectively, in comparison with hydroxyl radical. LDH was practically not inactivated by the superoxide anion. Despite the fact that the studied dehydrogenases belong to the same class of enzymes (oxidoreductases), all have a similar molecular weight and are tetramers, their susceptibility to free-radical damage varies. The differences in the radiosensitivity of the enzymes are not determined by the basic structural parameters analyzed. A significant role in inactivation susceptibility is played by the type of amino acid residues and their localization within enzyme molecules.

A Common Structural Component for β-Subunit Mediated Modulation of Slow Inactivation in Different KV Channels

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Nathalie Strutz-Seebohm

2013-06-01

Full Text Available Background/Aims: Potassium channels are tetrameric proteins providing potassium selective passage through lipid embedded proteinaceous pores with highest fidelity. The selectivity results from binding to discrete potassium binding sites and stabilization of a hydrated potassium ion in a central internal cavity. The four potassium binding sites, generated by the conserved TTxGYGD signature sequence are formed by the backbone carbonyls of the amino acids TXGYG. Residues KV1.5-Val481, KV4.3-Leu368 and KV7.1- Ile 313 represent the amino acids in the X position of the respective channels. Methods: Here, we study the impact of these residues on ion selectivity, permeation and inactivation kinetics as well as the modulation by β-subunits using site-specific mutagenesis, electrophysiological analyses and molecular dynamics simulations. Results: We identify this position as key in modulation of slow inactivation by structurally dissimilar β-subunits in different KV channels. Conclusion: We propose a model in which structural changes accompanying activation and β-subunit modulation allosterically constrain the backbone carbonyl oxygen atoms via the side chain of the respective X-residue in the signature sequence to reduce conductance during slow inactivation.

Inactivation of γ-aminobutyric acid aminotransferase by γ-ethynyl- and γ-vinyl GABA

International Nuclear Information System (INIS)

Silverman, R.B.; Burke, J.R.; Nanavati, S.M.

1989-01-01

γ-Ethynyl- and γ-vinyl GABA (vigabatrin) are anticonvulsant agents that have been shown to be mechanism-based inactivators of γ-aminobutyric acid aminotransferase (GABA-T). The inactivation mechanisms of these compounds have been investigated. Inactivation of GABA-T by [ 3 H]γ-ethynyl GABA led to the incorporation of 1.0 equiv of 3 H into the enzyme which is not released by enzyme denaturation. Inactivation by γ-ethynyl GABA of GABA-T reconstituted with [ 3 H]PLP followed by denaturation resulted in release of 3 H as PLP. Eight different possible adducts are consistent with that result. Experiments have been carried out to differentiate these possibilities. Similar studies have been carried out with γ-vinyl GABA. Inactivation by [ 14 C]γ-vinyl GABA resulted in the incorporation of 1.0 equiv of 14 C per active site. Unlike the case with γ-ethynyl GABA, γ-vinyl GABA inactivation of GABA-T reconstituted with [ 3 H]PLP followed by denaturation resulted in release of 3 H as PMP

Inactivation of catalase by free radicals derived from oxygen via gamma radiolysis

International Nuclear Information System (INIS)

Malhaire, J.P.; Gardes-Albert, M.; Ferradini, C.; Sabourault, D.; Ribiere, C.

1991-01-01

The inactivation of catalase (10 -5 mol/l) by OH· or OH·/O 2 - · free radicals, at pH 7.4, has been investigated using γ radiolysis with doses up to 9000 Gy. Maxima initial G-values of catalase inactivation have been determined. These values are inferior to those of the free radicals OH· and O 2 - · produced by water radiolysis. Nevertheless, the presence of O 2 /O 2 - · enhances the inactivation due to OH· radicals. The general shape of the inactivation curves as a function of the radiation dose is biphasic: an initial rapid phase (from 0 to ∼ 500 Gy) followed by a slow phase (from ∼ 500 to 9000 Gy). The addition of H 2 O 2 at the beginning of irradiation decreases the inactivation yield by OH· radicals. This phenomenon could be due to the formation of compound-I (catalase-H 2 O 2 ) which would be less sensitive towards OH· radicals than catalase. In the presence of 0.1 mol/l ethanol, catalase (5 x 10 -6 mol/l) is not inactived by O 2 - · and RO 2 · (from ethanol) radicals for an irradiation dose of 2000 Gy, implying a complete protecting effect by ethanol [fr

UV ability to destroy poliovirus end FRNA specific bacteriophages

Energy Technology Data Exchange (ETDEWEB)

Baron, J.; Joret, J.C.; Lesavre, J.; Perrot, J.Y.

1996-01-01

In France, the use of ultraviolet radiation to disinfect secondary effluents is only in its initial stage. The aim of this study was to examine the ability of UV to destroy Poliovirus Type 1 and FRNA specific bacteriophages (laboratory MS2 phages and indigenous phages). Concentrated viral solutions were mixed with secondary effluents artificially enriched with suspended solids and then irradiated at various UV dose in a collimated beam. Bacteriological analysis of Escherichia coli and enterococci were performed at the same time. UV were very efficient to kill Poliovirus : Inactivation of 3 and 5 log units were observed respectively at UV doses of 20 and 40 mW/cm{sup 2}. The Poliovirus disinfection rate was almost the same than Escherichia coli. Enterococci were more resistant than E. coli. Inactivation of MS2 bacteriophages was significantly correlated to UV dose following the relationship MS2 Inactivation = 0.047{sup *} Dose + 0,396. At UV dose of 20 mWs/cm{sup 2}, MS2 phages were 2.3 times more resistant to UV than Poliovirus, i.e. they need UV dose 2,3 times greater to be disinfected at the same level. A review of the literature has also shown that viruses more resistant to UV treatment have never been reported. All this would tend to confirm the interest of this group of virus as indicators of the disinfection efficiency of UV, which could indicate, on site, the inactivation of pathogenic viruses. Inactivation rates obtained for FRNA phages proved the good virucidal activity of UV. The inactivation of indigenous FRNA bacteriophages was not correlated with E. coli inactivation. On the other hand, it was correlated with enterococci inactivation. (Author). 23 refs., 7 figs., 4 tabs.

Inactivation of bacteria in sewage sludge by ionizing radiation, heat, and thermoradiation

International Nuclear Information System (INIS)

Brandon, J.R.; Langley, S.L.

1976-01-01

For purposes of animal feeding or fertilizer usage on edible crops, sewage sludge must be free of pathogenic organisms. Bacterial inactivation by a combination of heat and irradiation is shown to be effective. These results must be viewed in conjunction with those from studies of parasite egg inactivation, virus inactivation, and physical-chemical benefits in order to make a fair assessment of the value of the thermoradiation treatment compared to other possible sludge treatment processes

Inactivation of poliovirus in wastewater sludge with radiation and thermoradiation

International Nuclear Information System (INIS)

Ward, R.L.

1977-01-01

The effect of sludge on the rate of viral inactivation by radiation and thermoradiation was determined. The virus used for the experiments was the poliovirus type 1 strain CHAT, which was grown in HeLa cells. Radiation, heat, and thermoradiation treatments were carried out in a chamber specifically designed to permit rapid heating and cooling of the samples at the beginning and completion of treatment, respectively. The treated samples were then assayed for plaque-forming units on HeLa cells after sonication in 0.1% sodium dodecylsulfate (SDS). For the radiation treatment virus was diluted 10-fold into PBS containing new sludge, irradiated at 20 0 C with 137 Cs at a dose rate of 30 krads/min, and assayed for infectious virus. The results show that raw sludge is protective of poliovirus against ionizing radiation but that small concentrations of sludge are nearly as protective as large concentrations. When heat and radiation are given simultaneously, however, the amount of protection afforded by sludge is less than the additive effects of the individual treatments. This result is especially evident at low concentrations of sludge. It appears, therefore, that thermoradiation treatment may be an effective way of inactivation viruses in waters containing low concentrations of suspended solids

Anti-Human Endoglin (hCD105 Immunotoxin—Containing Recombinant Single Chain Ribosome-Inactivating Protein Musarmin 1

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Begoña Barriuso

2016-06-01

Full Text Available Endoglin (CD105 is an accessory component of the TGF-β receptor complex, which is expressed in a number of tissues and over-expressed in the endothelial cells of tumor neovasculature. Targeting endoglin with immunotoxins containing type 2 ribosome-inactivating proteins has proved an effective tool to reduce blood supply to B16 mice tumor xenografts. We prepared anti-endoglin immunotoxin (IT—containing recombinant musarmin 1 (single chain ribosome-inactivating proteins linked to the mouse anti-human CD105 44G4 mouse monoclonal antibody via N-succinimidyl 3-(2-pyridyldithio propionate (SPDP. The immunotoxin specifically killed L929 fibroblast mouse cells transfected with the short form of human endoglin with IC50 values in the range of 5 × 10−10 to 10−9 M.

Light-driven photosensitizer uptake increases Candida albicans photodynamic inactivation.

Science.gov (United States)

Romano, Renan A; Pratavieira, Sebastião; Silva, Ana P da; Kurachi, Cristina; Guimarães, Francisco E G

2017-11-01

Photodynamic Inactivation (PDI) is based on the use of a photosensitizer (PS) and light that results mainly in the production of reactive oxygen species, aiming to produce microorganism cell death. PS incubation time and light dose are key protocol parameters that influence PDI response; the correct choice of them can increase the efficiency of inactivation. The results of this study show that a minor change in the PDI protocol, namely light-driven incubation leads to a higher photosensitizer and more uniform cell uptake inside the irradiated zone. Furthermore, as the uptake increases, the damage caused by PDI also increases. The proposed light-driven incubation prior to the inactivation illumination dose has advantages when compared to the traditional PDI treatments since it can be more selective and effective. Using a violet light as pre-illumination (light-driven incubation) source and a red-light system as PDI source, it was possible to demonstrate that when compared to the traditional protocol of dark incubation, the pre-illuminated cell culture showed an inactivation increase of 7 log units. These in vitro results performed in Candida albicans cells may result in the introduction of a new protocol for PDI. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inactivation of acetylcholinesterase by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride.

Science.gov (United States)

Zang, Lun-Yi; Misra, Hara P

2003-12-01

The neurotoxicant 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been shown to reversibly inhibit the activity of acetylcholinesterase. The inactivation of the enzyme was detected by monitoring the accumulation of yellow color produced from the reaction between thiocholine and dithiobisnitrobenzoate ion. The kinetic parameter, Km for the substrate (acetylthiocholine), was found to be 0.216 mM and Ki for MPTP inactivation of acetylcholinesterase was found to be 2.14 mM. The inactivation of enzyme by MPTP was found to be dose-dependent. It was found that MPTP is neither a substrate of AChE nor the time-dependent inactivator. The studies of reaction kinetics indicate the inactivation of AChE to be a linear mixed-type inhibition. The dilution assays indicate that MPTP is a reversible inhibitor for AChE. These data suggest that once MPTP enters the basal ganglia of the brain, it can inactivate the acetylcholinesterase enzyme and thereby increase the acetylcholine level in the basal ganglia of brain, leading to potential cell dysfunction. It appears that the nigrostriatal toxicity by MPTP leading to Parkinson's disease-like syndrome may, in part, be mediated via the acetylcholinesterase inactivation.

Urease from Helicobacter pylori is inactivated by sulforaphane and other isothiocyanates

Science.gov (United States)

Fahey, Jed W.; Stephenson, Katherine K.; Wade, Kristina L.; Talalay, Paul

2013-01-01

Infections by Helicobacter pylori are very common, causing gastroduodenal inflammation including peptic ulcers, and increasing the risk of gastric neoplasia. The isothiocyanate (ITC) sulforaphane [SF; 1-isothiocyanato-4-(methylsulfinyl)butane] derived from edible crucifers such as broccoli is potently bactericidal against Helicobacter, including antibiotic-resistant strains, suggesting a possible dietary therapy. Gastric H. pylori infections express high urease activity which generates ammonia, neutralizes gastric acidity, and promotes inflammation. The finding that SF inhibits (inactivates) urease (jack bean and Helicobacter) raised the issue of whether these properties might be functionally related. The rates of inactivation of urease activity depend on enzyme and SF concentrations and show first order kinetics. Treatment with SF results in time-dependent increases in the ultraviolet absorption of partially purified Helicobacter urease in the 280–340 nm region. This provides direct spectroscopic evidence for the formation of dithiocarbamates between the ITC group of SF and cysteine thiols of urease. The potencies of inactivation of Helicobacter urease by isothiocyanates structurally related to SF were surprisingly variable. Natural isothiocyanates closely related to SF, previously shown to be bactericidal (berteroin, hirsutin, phenethyl isothiocyanate, alyssin, and erucin), did not inactivate urease activity. Furthermore, SF is bactericidal against both urease positive and negative H. pylori strains. In contrast, some isothiocyanates such as benzoyl-ITC, are very potent urease inactivators, but are not bactericidal. The bactericidal effects of SF and other ITC against Helicobacter are therefore not obligatorily linked to urease inactivation, but may reduce the inflammatory component of Helicobacter infections. PMID:23583386

Numerical evaluation of lactoperoxidase inactivation during continuous pulsed electric field processing.

Science.gov (United States)

Buckow, Roman; Semrau, Julius; Sui, Qian; Wan, Jason; Knoerzer, Kai

2012-01-01

A computational fluid dynamics (CFD) model describing the flow, electric field and temperature distribution of a laboratory-scale pulsed electric field (PEF) treatment chamber with co-field electrode configuration was developed. The predicted temperature increase was validated by means of integral temperature studies using thermocouples at the outlet of each flow cell for grape juice and salt solutions. Simulations of PEF treatments revealed intensity peaks of the electric field and laminar flow conditions in the treatment chamber causing local temperature hot spots near the chamber walls. Furthermore, thermal inactivation kinetics of lactoperoxidase (LPO) dissolved in simulated milk ultrafiltrate were determined with a glass capillary method at temperatures ranging from 65 to 80 °C. Temperature dependence of first order inactivation rate constants was accurately described by the Arrhenius equation yielding an activation energy of 597.1 kJ mol(-1). The thermal impact of different PEF processes on LPO activity was estimated by coupling the derived Arrhenius model with the CFD model and the predicted enzyme inactivation was compared to experimental measurements. Results indicated that LPO inactivation during combined PEF/thermal treatments was largely due to thermal effects, but 5-12% enzyme inactivation may be related to other electro-chemical effects occurring during PEF treatments. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

Dynein Light Intermediate Chain 2 Facilitates the Metaphase to Anaphase Transition by Inactivating the Spindle Assembly Checkpoint.

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Sagar P Mahale

Full Text Available The multi-functional molecular motor cytoplasmic dynein performs diverse essential roles during mitosis. The mechanistic importance of the dynein Light Intermediate Chain homologs, LIC1 and LIC2 is unappreciated, especially in the context of mitosis. LIC1 and LIC2 are believed to exist in distinct cytoplasmic dynein complexes as obligate subunits. LIC1 had earlier been reported to be required for metaphase to anaphase progression by inactivating the kinetochore-microtubule attachment-sensing arm of the spindle assembly checkpoint (SAC. However, the functional importance of LIC2 during mitosis remains elusive. Here we report prominent novel roles for the LIC2 subunit of cytoplasmic dynein in regulating the spindle assembly checkpoint. LIC2 depletion in mammalian cells led to prolonged metaphase arrest in the presence of an active SAC and also to stretched kinetochores, thus implicating it in SAC inactivation. Quantitative fluorescence microscopy of SAC components revealed accumulation of both attachment- and tension-sensing checkpoint proteins at metaphase kinetochores upon LIC2 depletion. These observations support a stronger and more diverse role in checkpoint inactivation for LIC2 in comparison to its close homolog LIC1. Our study uncovers a novel functional hierarchy during mitotic checkpoint inactivation between the closely related but homologous LIC subunits of cytoplasmic dynein. These subtle functional distinctions between dynein subpopulations could be exploited to study specific aspects of the spindle assembly checkpoint, which is a key mediator of fidelity in eukaryotic cell division.

Mechanism of inactivation of human leukocyte elastase by a chloromethyl ketone: kinetic and solvent isotope effect studies

International Nuclear Information System (INIS)

Stein, R.L.; Trainor, D.A.

1986-01-01

The mechanism of inactivation of human leukocyte elastase (HLE) by the chloromethyl ketone MeOSuc-Ala-Ala-Pro-Val-CH 2 Cl was investigated. The dependence of the first-order rate constant for inactivation on concentration of chloromethyl ketone is hyperbolic and suggests formation of a reversible Michaelis complex prior to covalent interaction between the enzyme and inhibitor. However, the observed Ki value is 10 microM, at least 10-fold lower than dissociation constants for complexes formed from interaction of HLE with structurally related substrates or reversible inhibitors, and suggests that Ki is a complex kinetic constant, reflecting the formation and accumulation of both the Michaelis complex and a second complex. It is proposed that this second complex is a hemiketal formed from attack of the active site serine on the carbonyl carbon of the inhibitor. The accumulation of this intermediate may be a general feature of reactions of serine proteases and chloromethyl ketones derived from specific peptides and accounts for the very low Ki values observed for these reactions. The solvent deuterium isotope effect (SIE) on the inactivation step (ki) is 1.58 +/- 0.07 and is consistent with rate-limiting, general-catalyzed attack of the active site His on the methylene carbon of the inhibitor with displacement of chloride anion. The general catalyst is thought to be the active site Asp. In contrast, the SIE on the second-order rate constant for HLE inactivation, ki/Ki, is inverse and equals 0.64 +/- 0.05

Inactivation of Smad4 in gastric carcinomas.

Science.gov (United States)

Powell, S M; Harper, J C; Hamilton, S R; Robinson, C R; Cummings, O W

1997-10-01

Allelic loss of chromosome 18q has been noted in intestinal type gastric adenocarcinomas. Smad4 is a gene located at 18q that was recently cloned in humans and found to be significantly altered in pancreatic cancers. We sought to determine whether Smad4 genetic alterations played a significant role in gastric tumorigenesis by studying 35 gastric adenocarcinomas of all histopathological types and pathological stages. Microdissected specimens were used for mutational analysis of Smad4 at the nucleotide level, including the entire coding region and intron/exon boundaries. Allelic imbalance was also analyzed at the Smad4 locus using two nearby microsatellite markers. One case of apparent biallelic inactivation of Smad4 was found in our study of 35 gastric carcinomas. A nonsense point mutation at codon 334 was demonstrated, which, similar to other Smad4 mutations, is predicted to truncate the conserved COOH-terminal domain of this protein. This Smad4 C to T transition mutation was proven to be somatically acquired. Allelic loss was also noted on chromosome 18q at a marker near Smad4 in this mutated gastric cancer, apparently producing complete inactivation of Smad4 in this tumor. Significant 18q allelic loss (56% of 34 informative cases) was noted in our gastric carcinomas using microsatellite markers near the Smad4 locus, regardless of histological subtype or pathological stage. Additionally, three cases of microsatellite instability were observed. Thus, Smad4 inactivation was noted in our gastric carcinomas; however, this event was rare. The frequent loss of chromosomal arm 18q observed in gastric cancers suggests the presence of other tumor suppressor genes in this region that are involved in gastric tumorigenesis. Further studies are needed to identify these other targets of inactivation during gastric cancer development.

A New Adjuvant Combined with Inactivated Influenza Enhances Specific CD8 T Cell Response in Mice and Decreases Symptoms in Swine Upon Challenge.

Science.gov (United States)

Bouguyon, Edwige; Goncalves, Elodie; Shevtsov, Alexander; Maisonnasse, Pauline; Remyga, Stepan; Goryushev, Oleg; Deville, Sebastien; Bertho, Nicolas; Ben Arous, Juliette

2015-11-01

Vaccination is the most effective way to control swine influenza virus (SIV) in the field. Classical vaccines are based on inactivated antigens formulated with an oil emulsion or a polymeric adjuvant. Standard adjuvants enhance the humoral response and orient the immune response toward a Th2 response. An important issue is that current vaccines do not protect against new strains. One approach to improve cross-protection is to enhance Th1 and cytotoxic responses. The development of adjuvants orienting the immune response of inactivated vaccines toward Th1/Cytotoxic responses would be highly beneficial. This study shows that the water in oil in water emulsion adjuvant Montanide™ ISA 201 VG allows the induction of anti-influenza CD8 T cell in mice and induces homologous protection against an H1N1 challenge in swine. Such adjuvants that induce both humoral and cell-mediated immunity could improve the protection conferred by SIV vaccines in the field.

Predicting Bacillus coagulans spores inactivation in tomato pulp under nonisothermal heat treatments.

Science.gov (United States)

Zimmermann, Morgana; Longhi, Daniel A; Schaffner, Donald W; Aragão, Gláucia M F

2014-05-01

The knowledge and understanding of Bacillus coagulans inactivation during a thermal treatment in tomato pulp, as well as the influence of temperature variation during thermal processes are essential for design, calculation, and optimization of the process. The aims of this work were to predict B. coagulans spores inactivation in tomato pulp under varying time-temperature profiles with Gompertz-inspired inactivation model and to validate the model's predictions by comparing the predicted values with experimental data. B. coagulans spores in pH 4.3 tomato pulp at 4 °Brix were sealed in capillary glass tubes and heated in thermostatically controlled circulating oil baths. Seven different nonisothermal profiles in the range from 95 to 105 °C were studied. Predicted inactivation kinetics showed similar behavior to experimentally observed inactivation curves when the samples were exposed to temperatures in the upper range of this study (99 to 105 °C). Profiles that resulted in less accurate predictions were those where the range of temperatures analyzed were comparatively lower (inactivation profiles starting at 95 °C). The link between fail prediction and both lower starting temperature and magnitude of the temperature shift suggests some chemical or biological mechanism at work. Statistical analysis showed that overall model predictions were acceptable, with bias factors from 0.781 to 1.012, and accuracy factors from 1.049 to 1.351, and confirm that the models used were adequate to estimate B. coagulans spores inactivation under fluctuating temperature conditions in the range from 95 to 105 °C. How can we estimate Bacillus coagulans inactivation during sudden temperature shifts in heat processing? This article provides a validated model that can be used to predict B. coagulans under changing temperature conditions. B. coagulans is a spore-forming bacillus that spoils acidified food products. The mathematical model developed here can be used to predict the spoilage

Inactivation of biological substances by local heating

Energy Technology Data Exchange (ETDEWEB)

Saito, Masahiro [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.

1982-09-01

Mechanism of inactivation of biological substances caused by local heating was investigated. The effect of hot-zone formation by local heating on reaction of radicals was previously evaluated. The thermal increase in a hot zone due to low energy LET x-rays had little effect on reactibility of the radicals, but, in a hot zone caused by high energy LET x-rays, formed radicals seemed immediately react to active biological molecules to inactivate them. Direct thermal effect on biological molecules was analysed. Thermal increase in a hot zone may induce degenaration of biological molecules which seems to occur in a short time judged from the extension of a hot zone and the duration of high temperature.

Conformational lock and dissociative thermal inactivation of lentil seedling amine oxidase.

Science.gov (United States)

Moosavi-Nejad, S Zahra; Moosavi-Movahedi, Ali-Akbar; Rezaei-Tavirani, Mostafa; Floris, Giovanni; Medda, Rosaria

2003-03-31

The kinetics of thermal inactivation of copper-containing amine oxidase from lentil seedlings were studied in a 100 mM potassium phosphate buffer, pH 7, using putrescine as the substrate. The temperature range was between 47-60 degrees C. The thermal inactivation curves were not linear at 52 and 57 degrees C; three linear phases were shown. The first phase gave some information about the number of dimeric forms of the enzyme that were induced by the higher temperatures using the "conformational lock" pertaining theory to oligomeric enzyme. The "conformational lock" caused two additional dimeric forms of the enzyme when the temperature increased to 57 degrees C. The second and third phases were interpreted according to a dissociative thermal inactivation model. These phases showed that lentil amine oxidase was reversibly-dissociated before the irreversible thermal inactivation. Although lentil amine oxidase is not a thermostable enzyme, its dimeric structure can form "conformational lock," conferring a structural tolerance to the enzyme against heat stress.

Hydroxylamine technique for in vitro prevention of penicillin inactivation of tobramycin.

Science.gov (United States)

Falkowski, A J; Creger, R J

1984-01-01

Hydroxylamine was evaluated and found to be a highly effective agent for the in vitro prevention of penicillin inactivation of tobramycin. This inactivation reaction resulted in an underestimation of tobramycin concentrations and was dependent on time, temperature, amount and type of penicillin, and amount of tobramycin. Plasma samples containing tobramycin and three clinically relevant concentrations of ticarcillin, carbenicillin, azlocillin, or piperacillin were incubated with and without hydroxylamine, and tobramycin concentrations were monitored at 0, 12, 24, 48, and 72 h. The inactivation reaction was found to be completely inhibited by hydroxylamine (1 mg/ml) compared with a 27 to 50% loss of measured tobramycin concentration in the unprotected tobramycin-penicillin samples. Hydroxylamine did not interfere with the Emit enzyme immunoassay (Syva Co.) at either high or low tobramycin concentrations. Hydroxylamine was effective in inhibiting the tobramycin inactivation at both room and refrigerator temperatures and was 100% effective in protecting tobramycin on a 1:1 molar basis. PMID:6393865

Microbial electrolytic disinfection process for highly efficient Escherichia coli inactivation

DEFF Research Database (Denmark)

Zhou, Shaofeng; Huang, Shaobin; Li, Xiaohu

2018-01-01

extensively studied for recalcitrant organics removal, its application potential towards water disinfection (e.g., inactivation of pathogens) is still unknown. This study investigated the inactivation of Escherichia coli in a microbial electrolysis cell based bio-electro-Fenton system (renamed as microbial......Water quality deterioration caused by a wide variety of recalcitrant organics and pathogenic microorganisms has become a serious concern worldwide. Bio-electro-Fenton systems have been considered as cost-effective and highly efficient water treatment platform technology. While it has been......]OH was identified as one potential mechanism for disinfection. This study successfully demonstrated the feasibility of bio-electro-Fenton process for pathogens inactivation, which offers insight for the future development of sustainable, efficient, and cost-effective biological water treatment technology....

Effect of Coat Layers in Bacillus Subtilis Spores Resistance to Photo-Catalytic Inactivation

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Luz del Carmen Huesca-Espitia

2017-10-01

Full Text Available Different water treatment processes (physical and chemical exist to obtain safe water for human or food industry supply. The advanced oxidation technologies are rising as a new alternative to eliminate undesirable chemicals and waterborne diseases. In this work, we analyze the power of the photo-assisted Fenton process using Fe(II/H2O2 and UV radiation (365 nm to inactivate Bacillus subtilis spores, considered among the most resistant biological structures known. Different concentrations of Fe(II, H2O2 and UV radiation (365 nm were used to inactivate wt and some coat spore mutants of B. subtilis. Wt spores of B. subtilis were inactivated after 60 min using this process. In general, all defective coat mutants were more sensitive than the wt spores and, particularly, the double mutant was 10 folds more sensitive than others being inactivated during the first 10 minutes using soft reaction conditions. Presence of Fe(II ions was found essential for spore inactivating process and, for those spores inactivated using the Fe(II/H2O2 under UV radiation process, it is suggested that coat structures are important to their resistance to the treatment process. The photo-assisted Fenton process using Fe(II, H2O2 and UV radiation (365 nm can be used to inactivate any water microorganisms with the same or less resistance that B. subtilis spores to produce safe drinking water in relatively short treatment time.

Buffer AVL Alone Does Not Inactivate Ebola Virus in a Representative Clinical Sample Type.

Science.gov (United States)

Smither, Sophie J; Weller, Simon A; Phelps, Amanda; Eastaugh, Lin; Ngugi, Sarah; O'Brien, Lyn M; Steward, Jackie; Lonsdale, Steve G; Lever, Mark S

2015-10-01

Rapid inactivation of Ebola virus (EBOV) is crucial for high-throughput testing of clinical samples in low-resource, outbreak scenarios. The EBOV inactivation efficacy of Buffer AVL (Qiagen) was tested against marmoset serum (EBOV concentration of 1 × 10(8) 50% tissue culture infective dose per milliliter [TCID50 · ml(-1)]) and murine blood (EBOV concentration of 1 × 10(7) TCID50 · ml(-1)) at 4:1 vol/vol buffer/sample ratios. Posttreatment cell culture and enzyme-linked immunosorbent assay (ELISA) analysis indicated that treatment with Buffer AVL did not inactivate EBOV in 67% of samples, indicating that Buffer AVL, which is designed for RNA extraction and not virus inactivation, cannot be guaranteed to inactivate EBOV in diagnostic samples. Murine blood samples treated with ethanol (4:1 [vol/vol] ethanol/sample) or heat (60°C for 15 min) also showed no viral inactivation in 67% or 100% of samples, respectively. However, combined Buffer AVL and ethanol or Buffer AVL and heat treatments showed total viral inactivation in 100% of samples tested. The Buffer AVL plus ethanol and Buffer AVL plus heat treatments were also shown not to affect the extraction of PCR quality RNA from EBOV-spiked murine blood samples. © Crown copyright 2015.

Characterization of Immune Responses to an Inactivated Avian Influenza Virus Vaccine Adjuvanted with Nanoparticles Containing CpG ODN.

Science.gov (United States)

Singh, Shirene M; Alkie, Tamiru N; Abdelaziz, Khaled Taha; Hodgins, Douglas C; Novy, Anastasia; Nagy, Éva; Sharif, Shayan

2016-06-01

Avian influenza virus (AIV), a mucosal pathogen, gains entry into host chickens through respiratory and gastrointestinal routes. Most commercial AIV vaccines for poultry consist of inactivated, whole virus with adjuvant, delivered by parenteral administration. Recent advances in vaccine development have led to the application of nanoparticle emulsion delivery systems, such as poly (d,l-lactic-co-glycolic acid) (PLGA) nanoparticles to enhance antigen-specific immune responses. In chickens, the Toll-like receptor 21 ligand, CpG oligodeoxynucleotides (ODNs), have been demonstrated to be immunostimulatory. The objective of this study was to compare the adjuvant potential of CpG ODN 2007 encapsulated in PLGA nanoparticles with nonencapsulated CpG ODN 2007 when combined with a formalin-inactivated H9N2 virus, through intramuscular and aerosol delivery routes. Chickens were vaccinated at days 7 and 21 posthatch for the intramuscular route and at days 7, 21, and 35 for the aerosol route. Antibody-mediated responses were evaluated weekly in sera and lacrimal secretions in specific pathogen-free chickens. The results indicate that nonencapsulated CpG ODN 2007 in inactivated AIV vaccines administered by the intramuscular route generated higher antibody responses compared to the encapsulated CpG ODN 2007 formulation by the same route. Additionally, encapsulated CpG ODN 2007 in AIV vaccines administered by the aerosol route elicited higher mucosal responses compared to nonencapsulated CpG ODN 2007. Future studies may be aimed at evaluating protective immune responses induced with PLGA encapsulation of AIV and adjuvants.

Cytogenetic and molecular studies on a recombinant human X chromosome: implications for the spreading of X chromosome inactivation

International Nuclear Information System (INIS)

Mohandas, T.; Geller, R.L.; Yen, P.H.; Rosendorff, J.; Bernstein, R.; Yoshida, A.; Shapiro, L.J.

1987-01-01

A pericentric inversion of human X chromosome and a recombinant X chromosome [rec(X)] derived from crossing-over within the inversion was identified in a family. The rec(X) had a duplication of the segment Xq26.3 → Xqter and a deletion of Xp22.3 → Xpter and was interpreted to be Xqter → Xq26.3::Xp22.3 → Xqter. To characterize the rec(X) chromosome, dosage blots were done on genomic DNA from carriers of this rearranged X chromosome using a number of X chromosome probes. Results showed that anonymous sequences from the distal end of the long arm to which probes 4D8, Hx120A, DX13, and St14 bind as well as the locus for glucose-6-phosphate dehydrogenase (G6PD) wee duplicated on the rec(X). Mouse-human cell hybrids were constructed that retained the rec(X) in the active or inactive state. Analyses of these hybrid clones for markers from the distal short arm of the X chromosome showed that the rec(X) retained the loci for steroid sulfatase (STS) and the cell surface antigen 12E7 (MIC2); but not the pseudoautosomal sequence 113D. These molecular studies confirm that the rec(X) is a duplication-deficiency chromosome as expected. In the inactive state in cell hybrids, STS and MIC2 (which usually escape X chromosome inactivation) were expressed from the rec(X), whereas G6PD was not. Therefore, in the rec(X) X chromosome inactivation has spread through STS and MIC2 leaving these loci unaffected and has inactivated G6PD in the absence of an inactivation center in the q26.3 → qter region of the human X chromosome. The mechanism of spreading of inactivation appears to operate in a sequence-specific fashion. Alternatively, STS and MIC2 may have undergone inactivation initially but could not be maintained in an inactive state

Reaction of uridine diphosphate galactose 4-epimerase with a suicide inactivator

International Nuclear Information System (INIS)

Flentke, G.R.; Frey, P.A.

1990-01-01

UDPgalactose 4-epimerase from Escherichia coli is rapidly inactivated by the compounds uridine 5'-diphosphate chloroacetol (UDC) and uridine 5'-diphosphate bromoacetol (UCB). Both UDC and UDB inactivate the enzyme in neutral solution concomitant with the appearance of chromophores absorbing maximally at 325 and 328 nm, respectively. The reaction of UDC with the enzyme follows saturation kinetics characterized by a K D of 0.110 mM and k inact of 0.84 min -1 at pH 8.5 and ionic strength 0.2 M. The inactivation by UDC is competitively inhibited by competitive inhibitors of UDPgalactose 4-epimerase, and it is accompanied by the tight but noncovalent binding of UDC to the enzyme in a stoichiometry of 1 mol of UDC/mol of enzyme dimer, corresponding to 1 mol of UDC/mol of enzyme-bound NAD + . The inactivation of epimerase by uridine 5'-diphosphate [ 2 H 2 ]chloroacetol proceeds with a primary kinetic isotope effect (k H /k D ) of 1.4. The inactivation mechanism is proposed to involve a minimum of three steps: (a) reversible binding of UDC to the active site of UDPgalactose 4-epimerase; (b) enolization of the chloroacetol moiety of enzyme-bound UDC, catalyzed by an enzymic general base at the active site; (c) alkylation of the nicotinamide ring of NAD + at the active site by the chloroacetol enolate. The resulting adduct between UDC and NAD + is proposed to be the chromophore with λ max at 325 nm. The enzymic general base required to facilitate proton transfer in redox catalysis by this enzyme may be the general base that facilitates enolization of the chloroacetol moiety of UDC in the inactivation reaction

Inactivation of 1-aminocyclopropane-1-carboxylate oxidase involves oxidative modifications.

Science.gov (United States)

Barlow, J N; Zhang, Z; John, P; Baldwin, J E; Schofield, C J

1997-03-25

1-Aminocyclopropane-1-carboxylate (ACC) oxidase catalyzes the final step in the biosynthesis of the plant signaling molecule ethylene. It is a member of the ferrous iron dependent family of oxidases and dioxygenases and is unusual in that it displays a very short half-life under catalytic conditions, typically less than 20 min, and a requirement for CO2 as an activator. The rates of inactivation of purified, recombinant ACC oxidase from tomato under various combinations of substrates and cofactors were measured. Inactivation was relatively slow in the presence of buffer alone (t1/2 > 1 h), but fast in the presence of ferrous iron and ascorbate (t1/2 approximately 10 min). The rate of iron/ascorbate-mediated inactivation was increased by the addition of ACC, unaffected by the addition of CO2 at saturation (supplied as bicarbonate) but decreased by the addition of catalase or ACC + CO2 at saturation (supplied as bicarbonate). Iron/ascorbate-mediated inactivation was accompanied by partial proteolysis as observed by SDS-PAGE analysis. The fragmentation pattern was altered when ACC was also included, suggesting that ACC can bind to ACC oxidase in the absence of bicarbonate. N-terminal sequencing of fragments resulted in identification of an internal cleavage site which we propose is proximate to active-site bound iron. Thus, ACC oxidase inactivates via relatively slow partial unfolding of the catalytically active conformation, oxidative damage mediated via hydrogen peroxide which is catalase protectable and oxidative damage to the active site which results in partial proteolysis and is not catalase protectable.

An inactivated yellow fever 17DD vaccine cultivated in Vero cell cultures.

Science.gov (United States)

Pereira, Renata C; Silva, Andrea N M R; Souza, Marta Cristina O; Silva, Marlon V; Neves, Patrícia P C C; Silva, Andrea A M V; Matos, Denise D C S; Herrera, Miguel A O; Yamamura, Anna M Y; Freire, Marcos S; Gaspar, Luciane P; Caride, Elena

2015-08-20

Yellow fever is an acute infectious disease caused by prototype virus of the genus Flavivirus. It is endemic in Africa and South America where it represents a serious public health problem causing epidemics of hemorrhagic fever with mortality rates ranging from 20% to 50%. There is no available antiviral therapy and vaccination is the primary method of disease control. Although the attenuated vaccines for yellow fever show safety and efficacy it became necessary to develop a new yellow fever vaccine due to the occurrence of rare serious adverse events, which include visceral and neurotropic diseases. The new inactivated vaccine should be safer and effective as the existing attenuated one. In the present study, the immunogenicity of an inactivated 17DD vaccine in C57BL/6 mice was evaluated. The yellow fever virus was produced by cultivation of Vero cells in bioreactors, inactivated with β-propiolactone, and adsorbed to aluminum hydroxide (alum). Mice were inoculated with inactivated 17DD vaccine containing alum adjuvant and followed by intracerebral challenge with 17DD virus. The results showed that animals receiving 3 doses of the inactivated vaccine (2 μg/dose) with alum adjuvant had neutralizing antibody titers above the cut-off of PRNT50 (Plaque Reduction Neutralization Test). In addition, animals immunized with inactivated vaccine showed survival rate of 100% after the challenge as well as animals immunized with commercial attenuated 17DD vaccine. Copyright © 2015 Elsevier Ltd. All rights reserved.

Crystal structure of lactose permease in complex with an affinity inactivator yields unique insight into sugar recognition

Energy Technology Data Exchange (ETDEWEB)

Chaptal, Vincent; Kwon, Seunghyug; Sawaya, Michael R.; Guan, Lan; Kaback, H. Ronald; Abramson, Jeff (UCLA); (TTU)

2011-08-29

Lactose permease of Escherichia coli (LacY) with a single-Cys residue in place of A122 (helix IV) transports galactopyranosides and is specifically inactivated by methanethiosulfonyl-galactopyranosides (MTS-gal), which behave as unique suicide substrates. In order to study the mechanism of inactivation more precisely, we solved the structure of single-Cys122 LacY in complex with covalently bound MTS-gal. This structure exhibits an inward-facing conformation similar to that observed previously with a slight narrowing of the cytoplasmic cavity. MTS-gal is bound covalently, forming a disulfide bond with C122 and positioned between R144 and W151. E269, a residue essential for binding, coordinates the C-4 hydroxyl of the galactopyranoside moiety. The location of the sugar is in accord with many biochemical studies.

Regulation of Na+ channel inactivation by the DIII and DIV voltage-sensing domains.

Science.gov (United States)

Hsu, Eric J; Zhu, Wandi; Schubert, Angela R; Voelker, Taylor; Varga, Zoltan; Silva, Jonathan R

2017-03-06

Functional eukaryotic voltage-gated Na + (Na V ) channels comprise four domains (DI-DIV), each containing six membrane-spanning segments (S1-S6). Voltage sensing is accomplished by the first four membrane-spanning segments (S1-S4), which together form a voltage-sensing domain (VSD). A critical Na V channel gating process, inactivation, has previously been linked to activation of the VSDs in DIII and DIV. Here, we probe this interaction by using voltage-clamp fluorometry to observe VSD kinetics in the presence of mutations at locations that have been shown to impair Na V channel inactivation. These locations include the DIII-DIV linker, the DIII S4-S5 linker, and the DIV S4-S5 linker. Our results show that, within the 10-ms timeframe of fast inactivation, the DIV-VSD is the primary regulator of inactivation. However, after longer 100-ms pulses, the DIII-DIV linker slows DIII-VSD deactivation, and the rate of DIII deactivation correlates strongly with the rate of recovery from inactivation. Our results imply that, over the course of an action potential, DIV-VSDs regulate the onset of fast inactivation while DIII-VSDs determine its recovery. © 2017 Hsu et al.

Influenza virus inactivated by artificial ribonucleases as a prospective killed virus vaccine.

Science.gov (United States)

Fedorova, Antonina A; Goncharova, Elena P; Kovpak, Mikhail P; Vlassov, Valentin V; Zenkova, Marina A

2012-04-19

The inactivation of viral particles with agents causing minimal damage to the structure of surface epitopes is a well-established approach for the production of killed virus vaccines. Here, we describe new agents for the inactivation of influenza virus, artificial ribonucleases (aRNases), which are chemical compounds capable of cleaving RNA molecules. Several aRNases were identified, exhibiting significant virucidal activity against the influenza A virus and causing a minimal effect on the affinity of monoclonal antibodies for the inactivated virus. Using a murine model of the influenza virus infection, a high protective activity of the aRNase-inactivated virus as a vaccine was demonstrated. The results of the experiments demonstrate the efficacy of novel chemical agents in the preparation of vaccines against influenza and, perhaps, against other infections caused by RNA viruses. Copyright © 2012 Elsevier Ltd. All rights reserved.

Influence of pH, Salt and Temperature on Pressure Inactivation of Hepatitis A virus

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The effects of pH (3-7), NaCl (0-6%), and temperature on pressure inactivation of hepatitis A virus (HAV) were determined. The HAV samples were treated at 400 MPa for 1 min at 5, 20, and 50C. Decreasing solution pH enhanced pressure inactivation of HAV. This enhanced inactivation effect was most e...

Inactivation of human enteric virus surrogates by high-intensity ultrasound.

Science.gov (United States)

Su, Xiaowei; Zivanovic, Svetlana; D'Souza, Doris H

2010-09-01

Foodborne viruses, especially human noroviruses, are recognized as leading causes of nonbacterial gastroenteritis worldwide. Development of effective inactivation methods is of great importance to control their spread. In this study, the effect of high-intensity ultrasound (HIUS) on the infectivity of three foodborne virus surrogates was investigated. The three surrogates, murine norovirus (MNV-1), feline calicivirus (FCV-F9), and MS2 bacteriophage, were diluted in phosphate-buffered saline (PBS) or orange juice to a titer of approximately 6 log(10) PFU/mL or approximately 4 log(10) PFU/mL. The ultrasound treatment was performed in duplicate by immersing the HIUS probe in virus-containing solution that was cooled in ice-water and sonicated at 20 kHz for 2, 5, 10, 15, 20, and 30 min with 30 sec on and 30 sec off. The infectivity of the recovered viruses after each ultrasound treatment was evaluated in duplicate using standardized plaque assays and compared to untreated controls. The results show that HIUS effectiveness depended on the virus type, the initial titer of the viruses, and the virus suspension solution. At titers of approximately 4 log(10) PFU/mL in PBS, feline calicivirus (FCV)-F9, MS2, and murine norovirus (MNV)-1 required 5-, 10-, and 30-min treatment, respectively, for complete inactivation. At initial titers of approximately 4 log(10) PFU/mL in orange juice, FCV-F9 required a 15-min treatment for complete inactivation and only a 1.55 log(10) PFU/mL reduction was achieved for MNV-1 in orange juice after 30-min treatment. Thus, inactivation by HIUS in orange juice was much lower than in PBS. Experiments using titers of approximately 6 log(10) PFU/mL showed decreased effects compared to those using titers of approximately 4 log(10) PFU/mL. These results indicate that HIUS alone is not sufficient to inactivate virus in food. Hurdle technologies that combine HIUS with antimicrobials, heat, or pressure should be explored for viral inactivation.

Evaluation of eco-friendly zwitterionic detergents for enveloped virus inactivation.

Science.gov (United States)

Conley, Lynn; Tao, Yinying; Henry, Alexis; Koepf, Edward; Cecchini, Douglas; Pieracci, John; Ghose, Sanchayita

2017-04-01

Inclusion of a detergent in protein biotherapeutic purification processes is a simple and very robust method for inactivating enveloped viruses. The detergent Triton X-100 has been used for many years and is part of the production process of several commercial therapeutic proteins. However, recent ecological studies have suggested that Triton X-100 and its break-down products can potentially behave as endocrine disrupters in aquatic organisms, raising concerns from an environmental impact perspective. As such, discharge of Triton X-100 into the waste water treatment plants is regulated in some jurisdictions, and alternative detergents for viral inactivation are required. In this work, we report on the identification and evaluation of more eco-friendly detergents as viable replacements for Triton X-100. Five detergent candidates with low to moderate environmental impact were initially identified and evaluated with respect to protein stability, followed by proof-of-concept virus inactivation studies using a model enveloped virus. From the set of candidates lauryldimethylamine N-oxide (LDAO) was identified as the most promising detergent due to its low ecotoxicity, robust anti-viral activity (LRV >4 at validation set-point conditions with X-MuLX), and absence of any negative impact on protein function. This detergent exhibited effective and robust virus inactivation in a broad range of protein concentrations, solution conductivities, pHs, and in several different cell culture fluid matrices. The only process parameter which correlated with reduced virus inactivation potency was LDAO concentration, and then only when the concentration was reduced to below the detergent's critical micelle concentration (CMC). Additionally, this work also demonstrated that LDAO was cleared to below detectable levels after Protein A affinity chromatography, making it suitable for use in a platform process that utilizes this chromatographic mode for protein capture. All these findings

Effect of rising time of rectangular pulse on inactivation of staphylococcus aureus by pulsed electric field

Science.gov (United States)

Zhang, Ruobing; Liang, Dapeng; Zheng, Nanchen; Xiao, Jianfu; Mo, Mengbin; Li, Jing

2013-03-01

Pulsed electric field (PEF) is a novel non-thermal food processing technology that involves the electric discharge of high voltage short pulses through the food product. In PEF study, rectangular pulses are most commonly used for inactivating microorganisms. However, little information is available on the inactivation effect of rising time of rectangular pulse. In this paper, inactivation effects, electric field strength, treatment time and conductivity on staphylococcus aureus inactivation were investigated when the pulse rising time is reduced from 2.5 μs to 200 ns. Experimental results showed that inactivation effect of PEF increased with electric field strength, solution conductivity and treatment time. Rising time of the rectangular pulse had a significant effect on the inactivation of staphylococcus aureus. Rectangular pulses with a rising time of 200 ns had a better inactivation effect than that with 2 μs. In addition, temperature increase of the solution treated by pulses with 200 ns rising time was lower than that with 2 μs. In order to obtain a given inactivation effect, treatment time required for the rectangular pulse with 200 ns rise time was shorter than that with 2 μs.

Effect of rising time of rectangular pulse on inactivation of staphylococcus aureus by pulsed electric field

International Nuclear Information System (INIS)

Zhang, Ruobing; Liang, Dapeng; Xiao, Jianfu; Mo, Mengbin; Li, Jing; Zheng, Nanchen

2013-01-01

Pulsed electric field (PEF) is a novel non-thermal food processing technology that involves the electric discharge of high voltage short pulses through the food product. In PEF study, rectangular pulses are most commonly used for inactivating microorganisms. However, little information is available on the inactivation effect of rising time of rectangular pulse. In this paper, inactivation effects, electric field strength, treatment time and conductivity on staphylococcus aureus inactivation were investigated when the pulse rising time is reduced from 2.5 μs to 200 ns. Experimental results showed that inactivation effect of PEF increased with electric field strength, solution conductivity and treatment time. Rising time of the rectangular pulse had a significant effect on the inactivation of staphylococcus aureus. Rectangular pulses with a rising time of 200 ns had a better inactivation effect than that with 2 μs. In addition, temperature increase of the solution treated by pulses with 200 ns rising time was lower than that with 2 μs. In order to obtain a given inactivation effect, treatment time required for the rectangular pulse with 200 ns rise time was shorter than that with 2 μs.

ASSESSING THE EFFECTIVENESS OF LOW PRESSURE ULTRAVIOLET LIGHT FOR INACTIVATING HELICOBACTER PYLORI

Science.gov (United States)

Three strains of Helicobacter pylori were exposed to ultraviolet (UV) light from a low-pressure source to determine log inactivation versus applied fluence. Results indicate that H. pylori is readily inactivated at UV fluences typically used in water treatment r...

Some factors affecting urokinase inactivation. [Gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Iwata, Hiroo; Iketa, Yoshito

1985-10-01

The enzymatic activity of urokinase adsorbed on various polymer surfaces was measured to study the interaction between protein and polymers. The polymer films on which urokinase was adsorbed were exposed to either a high temperature or ..gamma..-radiation. The thermal inactivation rates were higher on hydrophobic polymers such as poly(ethylene terephthalate), nylon 6, and poly(vinylidene fluoride) than hydrophilic polymers like cellulose and ethylene-vinyl alcohol copolymer, indicating their substantial dependence on the interfacial free energy between the polymer and water. A similar dependence was also seen for the ..gamma..-radiation inactivation. Urokinase adsorbed on the hydrophobic polymers lost more easily its enzymatic activity by exposure to ..gamma..-radiation. The interfacial free energy seems to be one of the driving forces to denaturate proteins on polymers.

Differential effects of parietal and frontal inactivations on reaction times distributions in a visual search task

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Claire eWardak

2012-06-01

Full Text Available The posterior parietal cortex participates to numerous cognitive functions, from perceptual to attentional and decisional processes. However, the same functions have also been attributed to the frontal cortex. We previously conducted a series of reversible inactivations of the lateral intraparietal area (LIP and of the frontal eye field (FEF in the monkey which showed impairments in covert visual search performance, characterized mainly by an increase in the mean reaction time (RT necessary to detect a contralesional target. Only subtle differences were observed between the inactivation effects in both areas. In particular, the magnitude of the deficit was dependant of search task difficulty for LIP, but not for FEF.In the present study, we re-examine these data in order to try to dissociate the specific involvement of these two regions, by considering the entire RT distribution instead of mean RT. We use the LATER model to help us interpret the effects of the inactivations with regard to information accumulation rate and decision processes. We show that: 1 different search strategies can be used by monkeys to perform visual search, either by processing the visual scene in parallel, or by combining parallel and serial processes; 2 LIP and FEF inactivations have very different effects on the RT distributions in the two monkeys. Although our results are not conclusive with regards to the exact functional mechanisms affected by the inactivations, the effects we observe on RT distributions could be accounted by an involvement of LIP in saliency representation or decision-making, and an involvement of FEF in attentional shifts and perception. Finally, we observe that the use of the LATER model is limited in the context of a visual search as it cannot fit all the behavioural strategies encountered. We propose that the diversity in search strategies observed in our monkeys also exists in individual human subjects and should be considered in future

Inactivation of Staphylococcus aureus and Enterococcus faecalis by a direct-current, cold atmospheric-pressure air plasma microjet.

Science.gov (United States)

Tian, Ye; Sun, Peng; Wu, Haiyan; Bai, Na; Wang, Ruixue; Zhu, Weidong; Zhang, Jue; Liu, Fuxiang

2010-07-01

A direct-current, cold atmospheric-pressure air plasma microjet (PMJ) was performed to inactivate Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis) in air. The process of sterilization and morphology of bacteria was observed. We wish to know the possible inactivation mechanisms of PMJ and explore a potential application in dental and other temperature sensitive treatment. In this study, we employed a direct current, atmospheric pressure, cold air PMJ to inactivate bacterias. Scanning electron microscopy was employed to evaluate the morphology of S. aureus and showed rupture of cell walls after the plasma treatment and Optical emission spectrum (OES) were used to understand the possible inactivation mechanisms of PMJ. The inactivation rates could reach 100% in 5 min. When the distance between the exit nozzle of the PMJ device and Petri dish was extended from 1 cm to 3 cm, effective inactivation was also observed with a similar inactivation curve. The inactivation of bacteria is attributed to the abundant reactive oxygen and nitrogen species, as well as ultroviolet radiation in the plasma. Different life spans and defensibilities of these killing agents may hold the key to understanding the different inactivation curves at different treatment distances.

Singlet oxygen treatment of tumor cells triggers extracellular singlet oxygen generation, catalase inactivation and reactivation of intercellular apoptosis-inducing signaling☆

Science.gov (United States)

Riethmüller, Michaela; Burger, Nils; Bauer, Georg

2015-01-01

Intracellular singlet oxygen generation in photofrin-loaded cells caused cell death without discrimination between nonmalignant and malignant cells. In contrast, extracellular singlet oxygen generation caused apoptosis induction selectively in tumor cells through singlet oxygen-mediated inactivation of tumor cell protective catalase and subsequent reactivation of intercellular ROS-mediated apoptosis signaling through the HOCl and the NO/peroxynitrite signaling pathway. Singlet oxygen generation by extracellular photofrin alone was, however, not sufficient for optimal direct inactivation of catalase, but needed to trigger the generation of cell-derived extracellular singlet oxygen through the interaction between H2O2 and peroxynitrite. Thereby, formation of peroxynitrous acid, generation of hydroxyl radicals and formation of perhydroxyl radicals (HO2.) through hydroxyl radical/H2O2 interaction seemed to be required as intermediate steps. This amplificatory mechanism led to the formation of singlet oxygen at a sufficiently high concentration for optimal inactivation of membrane-associated catalase. At low initial concentrations of singlet oxygen, an additional amplification step needed to be activated. It depended on singlet oxygen-dependent activation of the FAS receptor and caspase-8, followed by caspase-8-mediated enhancement of NOX activity. The biochemical mechanisms described here might be considered as promising principle for the development of novel approaches in tumor therapy that specifically direct membrane-associated catalase of tumor cells and thus utilize tumor cell-specific apoptosis-inducing ROS signaling. PMID:26225731

Carvacrol suppresses high pressure high temperature inactivation of Bacillus cereus spores.

Science.gov (United States)

Luu-Thi, Hue; Corthouts, Jorinde; Passaris, Ioannis; Grauwet, Tara; Aertsen, Abram; Hendrickx, Marc; Michiels, Chris W

2015-03-16

The inactivation of bacterial spores generally proceeds faster and at lower temperatures when heat treatments are conducted under high pressure, and high pressure high temperature (HPHT) processing is, therefore, receiving an increased interest from food processors. However, the mechanisms of spore inactivation by HPHT treatment are poorly understood, particularly at moderately elevated temperature. In the current work, we studied inactivation of the spores of Bacillus cereus F4430/73 by HPHT treatment for 5 min at 600MPa in the temperature range of 50-100°C, using temperature increments of 5°C. Additionally, we investigated the effect of the natural antimicrobial carvacrol on spore germination and inactivation under these conditions. Spore inactivation by HPHT was less than about 1 log unit at 50 to 70°C, but gradually increased at higher temperatures up to about 5 log units at 100°C. DPA release and loss of spore refractility in the spore population were higher at moderate (≤65°C) than at high (≥70°C) treatment temperatures, and we propose that moderate conditions induced the normal physiological pathway of spore germination resulting in fully hydrated spores, while at higher temperatures this pathway was suppressed and replaced by another mechanism of pressure-induced dipicolinic acid (DPA) release that results only in partial spore rehydration, probably because spore cortex hydrolysis is inhibited. Carvacrol strongly suppressed DPA release and spore rehydration during HPHT treatment at ≤65°C and also partly inhibited DPA release at ≥65°C. Concomitantly, HPHT spore inactivation was reduced by carvacrol at 65-90°C but unaffected at 95-100°C. Copyright © 2014 Elsevier B.V. All rights reserved.

Protocol for Determining Ultraviolet Light Emitting Diode (UV-LED) Fluence for Microbial Inactivation Studies.

Science.gov (United States)

Kheyrandish, Ataollah; Mohseni, Madjid; Taghipour, Fariborz

2018-06-15

Determining fluence is essential to derive the inactivation kinetics of microorganisms and to design ultraviolet (UV) reactors for water disinfection. UV light emitting diodes (UV-LEDs) are emerging UV sources with various advantages compared to conventional UV lamps. Unlike conventional mercury lamps, no standard method is available to determine the average fluence of the UV-LEDs, and conventional methods used to determine the fluence for UV mercury lamps are not applicable to UV-LEDs due to the relatively low power output, polychromatic wavelength, and specific radiation profile of UV-LEDs. In this study, a method was developed to determine the average fluence inside a water suspension in a UV-LED experimental setup. In this method, the average fluence was estimated by measuring the irradiance at a few points for a collimated and uniform radiation on a Petri dish surface. New correction parameters were defined and proposed, and several of the existing parameters for determining the fluence of the UV mercury lamp apparatus were revised to measure and quantify the collimation and uniformity of the radiation. To study the effect of polychromatic output and radiation profile of the UV-LEDs, two UV-LEDs with peak wavelengths of 262 and 275 nm and different radiation profiles were selected as the representatives of typical UV-LEDs applied to microbial inactivation. The proper setup configuration for microorganism inactivation studies was also determined based on the defined correction factors.

Humoral response to 2 inactivated bluetongue virus serotype-8 vaccines in South American camelids.

Science.gov (United States)

Zanolari, P; Bruckner, L; Fricker, R; Kaufmann, C; Mudry, M; Griot, C; Meylan, M

2010-01-01

Bluetongue virus serotype 8 (BTV-8) has caused disease in domestic ruminants in several countries of northern Europe since 2006. In 2008 a mass-vaccination program was launched in most affected countries using whole virus inactivated vaccines. To evaluate 2 inactivated vaccines (Bovilis BTV 8; BTVPUR AlSap8) for immunogenicity and safety against BTV-8 in South American camelids (SAC) in a field trial. Forty-two SAC (25 Alpacas, 17 Llamas) aged between 1 and 16 years. The animals were vaccinated twice at intervals of 21 days. They were observed clinically for adverse local, systemic, or both reactions throughout the trial. Blood samples collected on days 0, 14, 21, 43, and 156 after vaccination were tested for the presence of BTV-8 virus by real time-polymerase chain reaction and of specific antibodies by competitive ELISA and a serum neutralization test. All vaccinated animals developed antibodies to BTV-8 after the 2nd administration of the vaccine. No adverse effects were observed except for moderate local swellings at the injection site, which disappeared within 21 days. Slightly increased body temperatures were only observed in the first 2 days after vaccination. The BTV was not detected in any of the samples analyzed. The administration of the 2 inactivated commercial vaccines was safe and induced seroconversion against BTV-8 in all vaccinated animals. The results of this study suggest that 2 doses injected 3 weeks apart is a suitable vaccination regimen for SAC.

Inactivation of Ichthyophonus spores using sodium hypochlorite and polyvinyl pyrrolidone iodine.

Science.gov (United States)

Hershberger, P K; Pacheco, C A; Gregg, J L

2008-11-01

Chlorine and iodine solutions were effective at inactivating Ichthyophonus spores in vitro. Inactivation in sea water increased directly with halogen concentration and exposure duration, with significant differences (P < 0.05) from controls occurring at all chlorine concentrations and exposure durations tested (1.5-13.3 ppm for 1-60 min) and at most iodine concentrations and exposure durations tested (1.2 ppm for 60 min and 5.9-10.7 ppm for 1-60 min). However, 10-fold reductions in spore viability occurred only after exposure to halogen solutions at higher concentrations and/or longer durations (13 ppm total chlorine for 1-60 min, 5.9 ppm total iodine for 60 min, and 10.7 ppm total iodine for 1-60 min). Inactivation efficacy was greater when halogen solutions were prepared in fresh water, presumably because of combined effects of halogen-induced inactivation and general spore instability in fresh water. The results have practical implications for disinfection and biocontainment in research laboratories and other facilities that handle live Ichthyophonus cultures and/or infected fish.

A Mouse Model of Enterovirus D68 Infection for Assessment of the Efficacy of Inactivated Vaccine

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Chao Zhang

2018-01-01

Full Text Available In recent years, enterovirus D68 (EVD68 has been reported increasingly to be associated with severe respiratory tract infections and acute flaccid myelitis (AFM in children all over the world. Yet, no effective vaccines or antiviral drugs are currently available for EVD68. Although several experimental animal models have been developed, immunogenicity and protective efficacy of inactivated EVD68 vaccines has not been fully evaluated. To promote the development of vaccines, we established an Institute of Cancer Research (ICR suckling mouse model of EVD68 infection in this study. The results showed that ICR neonatal mice up to about nine days of age were susceptible to infection with EVD68 clinical strain US/MO/14-18947 by intraperitoneal injection. The infected mice exhibited progressive limb paralysis prior to death and the mortality of mice was age- and virus dose-dependent. Tissue viral load analysis showed that limb muscle and spinal cord were the major sites of viral replication. Moreover, histopathologic examination revealed the severe necrosis of the limb and juxtaspinal muscles, suggesting that US/MO/14-18947 has a strong tropism toward muscle tissues. Additionally, β-propiolactone-inactivated EVD68 vaccine showed high purity and quality and induced robust EVD68-specific neutralizing antibody responses in adult mice. Importantly, results from both antisera transfer and maternal immunization experiments clearly showed that inactivated EVD68 vaccine was able to protect against lethal viral infection in the mouse model. In short, these results demonstrate the successful establishment of the mouse model of EVD68 infection for evaluating candidate vaccines against EVD68 and also provide important information for the development of inactivated virus-based EVD68 vaccines.

Thermal and Carbon Dioxide Inactivation of Alkaline Phosphatase in Buffer and Milk

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Osman Erkmen

2004-01-01

Full Text Available The effects of temperature and CO2 treatment on the inactivation of alkaline phosphatase (ALP were studied. The thermal stability of ALP was found to be significantly (P< 0.05 different in glycine/NaOH buffer, pasteurized milk and raw milk. ALP was completely inactivated in the buffer at 60, 70 and 80 °C but approximately 12 % of activity was present at 50 °C after 55 min of treatment. The time required for complete inactivation of the enzyme in the buffer was reduced from 50 to 4 min as temperature increased from 60 to 80 °C. Complete inactivation of the enzyme in pasteurized milk was achieved at 70 and 80 °C but 28 and 15 % of ALP activity was still present at 50 and 60 °C after 120 min of treatment. Inactivation time for raw milk was reduced nearly 18-fold by increasing temperature from 50 to 70 °C. ALP in the buffer exposed to CO2 (under atmospheric pressure treatment at different temperatures showed a decrease in enzyme activity. Inactivation was found to be higher as the temperature increased from 20 to 50 °C. At the end of a 30-min treatment, residual ALP activity was found to be 84 and 19 % at 20 and 50 °C, respectively. Faster drop in pH and enzyme activity occurred within 5 min. The change in pH and enzyme activity dependant on CO2 treatment was not observed in raw milk mainly due to strong buffering capacity of milk.

[Effect of Photodynamic Inactivation (PDI) using Riboflavin-Conjugated Antibody against Staphylococcus aureus].

Science.gov (United States)

Song, X; Stachon, T; Seitz, B; Wang, J; Bischoff, M; Langenbucher, A; Janunts, E; Szentmáry, N

2015-08-01

Crosslinking/riboflavin-UVA photodynamic therapy is a potential treatment alternative in antibiotic resistant infectious keratitis. For photodynamic therapy a specific (against bacteria) conjugated antibody may be used in order to increase the effect of the treatment. In our present study we analysed the impact of photodynamic inactivation using riboflavin-conjugated antibody or riboflavin alone on Staphylococcus aureus, in vitro. Staphylococcus aureus (S. aureus) was incubated in 1 : 100 diluted riboflavin-conjugated antibody (R-AB) for 30 minutes in darkness. Following UVA-light illumination (375 nm) with an energy dose of 2, 3, 4 and 8 J/cm(2), bacteria were brought to blood agar Plates for 24 hours before colony-forming unit (CFU) counting. In an additional group, we incubated bacteria to 0, 0.05 or 0.1 % riboflavin 5-phosphate as described above followed by illumination using UVA light (375 nm) with an energy dose of 2 J/cm(2), before CFU counting. The number of CFU decreased significantly (inactivation of 36 %, p = 0.022) using 1 : 100 diluted riboflavin-conjugated antibody and 2 J/cm(2) UVA-light illumination, compared to untreated controls. The use of 3, 4 und 8 J/cm(2) energy dose and R-AB in 1 : 100 dilution did not further change the decrease of CFU (inactivation of 39, 39 and 40 %; p = 0.016; p = 0.016; p = 0.015). The use of 0.05 % or 0.1 % riboflavin 5-phosphate alone and UVA-light illumination reduced the CFU count significantly (inactivation of 73 and 55 %; p = 0.002; p = 0.005), compared to untreated controls. The use of riboflavin-conjugated antibody or 0.05 % or 0.1 % riboflavin 5-phosphate and UVA-light illumination reduces the number of CFU of S. aureus. However, none of these photodynamic therapies reached the necessary 99 % killing rate of these bacteria. Further work is needed to increase the efficacy of riboflavin-conjugated antibodies against antibiotic resistant bacteria. Georg

Mean inactivation dose: a useful concept for intercomparison of human cell survival curves

International Nuclear Information System (INIS)

Fertil, B.; Dertinger, H.; Courdi, A.; Malaise, E.P.

1984-01-01

The mean inactivation dose (anti D) is calculated for published in vitro survival curves obtained from cell lines of both normal and neoplastic human tissues. Cells belonging to different histological categories (melanomas, carcinomas, etc.) are shown to be characterized by distinct values of anti D which are related to the clinical radiosensitivity of tumors from these categories. Compared to other ways of representing in vitro radiosensitivity, e.g., by the multitarget parameters D 8 and n, the parameter anti D has several specific advantages

Inactivation of Stac3 causes skeletal muscle defects and perinatal death in mice

OpenAIRE

Reinholt, Brad Michael

2012-01-01

The Src homology 3 domain (SH3) and cysteine rich domain (C1) 3 (Stac3) gene is a novel gene copiously expressed in skeletal muscle. The objective of this research was to determine the role of Stac3 in development, specifically in skeletal muscle. We achieved this objective by evaluating the phenotypic effects of Stac3 gene inactivation on development in mice. At birth homozygous Stac3 null (Stac3-/-) mice died perinatally and remained in fetal position with limp limbs, but possessed otherwis...

Nucleus incertus inactivation impairs spatial learning and memory in rats.

Science.gov (United States)

Nategh, Mohsen; Nikseresht, Sara; Khodagholi, Fariba; Motamedi, Fereshteh

2015-02-01

Nucleus incertus (NI) is a pontine nucleus which releases mainly GABA and relaxin-3 in rats. Its suggested functions include response to stress, arousal, and modulation of hippocampal theta rhythm. Since the role of NI in learning and memory has not been well characterized, therefore the involvement of this nucleus in spatial learning and memory and the aftermath hippocampal levels of c-fos and pCREB were evaluated. NI was targeted by implanting cannula in male rats. For reference memory, NI was inactivated by lidocaine (0.4 μl, 4%) at three stages of acquisition, consolidation and retrieval in Morris water maze paradigm. For working memory, NI was inactivated in acquisition and retrieval phases. Injection of lidocaine prior to the first training session of reference memory significantly increased the distance moved, suggesting that inactivation of NI delays acquisition in this spatial task. Inactivation also interfered with the retrieval phase of spatial reference memory, as the time in target quadrant for lidocaine group was less, and the escape latency was higher compared to the control group. However, no difference was observed in the consolidation phase. In the working memory task, with inter-trial intervals of 75 min, the escape latency was higher when NI was inactivated in the retrieval phase. In addition, c-fos and pCREB/CREB levels decreased in NI-inhibited rats. This study suggests that nucleus incertus might participate in acquisition of spatial reference, and retrieval of both spatial reference and working memory. Further studies should investigate possible roles of NI in the hippocampal plasticity. Copyright © 2014 Elsevier Inc. All rights reserved.

Pathogen inactivation of Dengue virus in red blood cells using amustaline and glutathione.

Science.gov (United States)

Aubry, Maite; Laughhunn, Andrew; Santa Maria, Felicia; Lanteri, Marion C; Stassinopoulos, Adonis; Musso, Didier

2017-12-01

Dengue virus (DENV) is an arbovirus primarily transmitted through mosquito bite; however, DENV transfusion-transmitted infections (TTIs) have been reported and asymptomatic DENV RNA-positive blood donors have been identified in endemic countries. DENV is considered a high-risk pathogen for blood safety. One of the mitigation strategies to prevent arbovirus TTIs is pathogen inactivation. In this study we demonstrate that the amustaline and glutathione (S-303/GSH) treatment previously found effective against Zika virus in red blood cells (RBCs) is also effective in inactivating DENV. Red blood cells were spiked with high levels of DENV. Viral RNA loads and infectious titers were measured in the untreated control and before and after pathogen inactivation treatment of RBC samples. DENV infectivity was also assessed over five successive cell culture passages to detect any potential residual replicative virus. The mean ± SD DENV titer in RBCs before inactivation was 6.61 ± 0.19 log 50% tissue culture infectious dose (TCID 50 )/mL and the mean viral RNA load was 8.42 log genome equivalents/mL. No replicative DENV was detected either immediately after completion of treatment using S-303/GSH or after cell culture passages. Treatment using S-303/GSH inactivated high levels of DENV in RBCs to the limit of detection. In combination with previous studies showing the effective inactivation of DENV in plasma and platelets using the licensed amotosalen/UVA system, this study demonstrates that high levels of DENV can be inactivated in all blood components. © 2017 The Authors Transfusion published by Wiley Periodicals, Inc. on behalf of AABB.

Sunlight inactivation of Escherichia coli in waste stabilization microcosms in a sahelian region (Ouagadougou, Burkina Faso).

Science.gov (United States)

Maïga, Ynoussa; Denyigba, Kokou; Wethe, Joseph; Ouattara, Aboubakar Sidiki

2009-02-09

Experiments on sunlight inactivation of Escherichia coli were conducted from November 2006 to June 2007 in eight outdoors microcosms with different depths filled with maturation pond wastewater in order to determine pond depth influence on sunlight inactivation of E. coli. The long-term aim was to maximize sunlight inactivation of waterborne pathogens in waste stabilization ponds (WSPs) in sahelian regions where number of sunny days enable longer exposure of wastewater to sunlight. The inactivation was followed during daylight from 8.00 h to 17.00 h and during the night. Sunlight inactivation rates (K(S)), as a function of cumulative global solar radiation (insolation), were 16 and 24 times higher than the corresponding dark inactivation (K(D)) rates, respectively in cold and warm season. In warm season, E. coli was inactivated far more rapidly. Inactivation of E. coli follows the evolution of radiation during the day. In shallow depth microcosms, E. coli was inactivated far more rapidly than in high depth microcosms. The physical chemical parameters [pH, dissolved oxygen (DO)] of microcosms water were higher in shallow depth microcosms than in high depth microcosms suggesting a synergistic effect of sunlight and these parameters to damage E. coli. To increase the efficiency of the elimination of waterborne bacteria, the use of maturation ponds with intermediate depths (0.4m) would be advisable in view of the high temperatures and thus evaporation recorded in sahelian regions.

Study on the inactivation of intracellular enzyme molecules by X-ray irradiation

International Nuclear Information System (INIS)

Lee, S.B.

1977-01-01

Inactivation of the glutamic acid dehydrogenase and glucose-6-phosphate dehydrogenase enzyme molecules in the Ehrlich ascites tumor cells of the mouse were studied. The above mentioned intracellular enzyme molecules were irradiated by the X-ray radiation under the condition of 65 kV, 1 Amp under the atmosphere of nitrogen gases and by 4 0 C. Thereby, irradiation doses were 580 KR/min(error: +-3%). After irradiation, the cell homogentes were prepared through liquid air techniques. There after, the activities of the enzymes were measured with photometric method given by O. Warburg and W. Christian. The dose effect curves of the activities of the two enzymes by the X-ray irradiation showed both exponential and the inactivation doses were 6.5x10 6 and 5.0x10 6 R respectively. These results showed one side that the inactivation process of the intracellular enzyme molecules was one hit reaction after target theory, and the other side that this inactivation process could not be the primary causes of the death through X-ray irradiation of the vertebrate animals, because of the high resistance of the intracellular protein molecules against X-ray irradiation. The one hit reaction by the inactivation process of the irradiated intracellular enzyme molecules was discussed. (author)

Mirasol PRT system inactivation efficacy evaluated in platelet concentrates by bacteria-contamination model

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Jocić Miodrag

2011-01-01

Full Text Available Background/Aim. Bacterial contamination of blood components, primarily platelet concentrates (PCs, has been identified as one of the most frequent infectious complications in transfusion practice. PC units have a high risk for bacterial growth/multiplication due to their storage at ambient temperature (20 ± 2°C. Consequences of blood contamination could be effectively prevented or reduced by pathogen inactivation systems. The aim of this study was to determine the Mirasol pathogen reduction technology (PRT system efficacy in PCs using an artificial bacteria-contamination model. Methods. According to the ABO blood groups, PC units (n = 216 were pooled into 54 pools (PC-Ps. PC-Ps were divided into three equal groups, with 18 units in each, designed for an artificial bacteria-contamination. Briefly, PC-Ps were contaminated by Staphylococcus epidermidis, Staphylococcus aureus or Escherichia coli in concentrations 102 to 107 colony forming units (CFU per unit. Afterward, PC-Ps were underwent to inactivation by Mirasol PRT system, using UV (l = 265-370 nm activated riboflavin (RB. All PC-Ps were assayed by BacT/Alert Microbial Detection System for CFU quantification before and after the Mirasol treatment. Samples from non-inactivated PC-P units were tested after preparation and immediately following bacterial contamination. Samples from Mirasol treated units were quantified for CFUs one hour, 3 days and 5 days after inactivation. Results. A complete inactivation of all bacteria species was obtained at CFU concentrations of 102 and 103 per PC-P unit through storage/ investigation period. The most effective inactivation (105 CFU per PC-P unit was obtained in Escherichia coli setting. Contrary, inactivation of all the three tested bacteria species was unworkable in concentrations of ≥ 106 CFU per PC-P unit. Conclusion. Efficient inactivation of investigated bacteria types with a significant CFU depletion in PC-P units was obtained - 3 Log for all

Evaluation of Different Dose-Response Models for High Hydrostatic Pressure Inactivation of Microorganisms

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Sencer Buzrul

2017-09-01

Full Text Available Modeling of microbial inactivation by high hydrostatic pressure (HHP requires a plot of the log microbial count or survival ratio versus time data under a constant pressure and temperature. However, at low pressure and temperature values, very long holding times are needed to obtain measurable inactivation. Since the time has a significant effect on the cost of HHP processing it may be reasonable to fix the time at an appropriate value and quantify the inactivation with respect to pressure. Such a plot is called dose-response curve and it may be more beneficial than the traditional inactivation modeling since short holding times with different pressure values can be selected and used for the modeling of HHP inactivation. For this purpose, 49 dose-response curves (with at least 4 log10 reduction and ≥5 data points including the atmospheric pressure value (P = 0.1 MPa, and with holding time ≤10 min for HHP inactivation of microorganisms obtained from published studies were fitted with four different models, namely the Discrete model, Shoulder model, Fermi equation, and Weibull model, and the pressure value needed for 5 log10 (P5 inactivation was calculated for all the models above. The Shoulder model and Fermi equation produced exactly the same parameter and P5 values, while the Discrete model produced similar or sometimes the exact same parameter values as the Fermi equation. The Weibull model produced the worst fit (had the lowest adjusted determination coefficient (R2adj and highest mean square error (MSE values, while the Fermi equation had the best fit (the highest R2adj and lowest MSE values. Parameters of the models and also P5 values of each model can be useful for the further experimental design of HHP processing and also for the comparison of the pressure resistance of different microorganisms. Further experiments can be done to verify the P5 values at given conditions. The procedure given in this study can also be extended for

Inactivation of Staphylococcus aureus and Enterococcus faecalis by a direct-current, cold atmospheric-pressure air plasma microjet☆

Science.gov (United States)

Tian, Ye; Sun, Peng; Wu, Haiyan; Bai, Na; Wang, Ruixue; Zhu, Weidong; Zhang, Jue; Liu, Fuxiang

2010-01-01

Objective A direct-current, cold atmospheric-pressure air plasma microjet (PMJ) was performed to inactivate Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis) in air. The process of sterilization and morphology of bacteria was observed. We wish to know the possible inactivation mechanisms of PMJ and explore a potential application in dental and other temperature sensitive treatment. Methods In this study, we employed a direct current, atmospheric pressure, cold air PMJ to inactivate bacterias. Scanning electron microscopy was employed to evaluate the morphology of S. aureus and showed rupture of cell walls after the plasma treatment and Optical emission spectrum (OES) were used to understand the possible inactivation mechanisms of PMJ. Results The inactivation rates could reach 100% in 5 min. When the distance between the exit nozzle of the PMJ device and Petri dish was extended from 1 cm to 3 cm, effective inactivation was also observed with a similar inactivation curve. Conclusion The inactivation of bacteria is attributed to the abundant reactive oxygen and nitrogen species, as well as ultroviolet radiation in the plasma. Different life spans and defensibilities of these killing agents may hold the key to understanding the different inactivation curves at different treatment distances. PMID:23554639

Inactivation kinetics and efficiencies of UV-LEDs against Pseudomonas aeruginosa, Legionella pneumophila, and surrogate microorganisms.

Science.gov (United States)

Rattanakul, Surapong; Oguma, Kumiko

2018-03-01

To demonstrate the effectiveness of UV light-emitting diodes (UV-LEDs) to disinfect water, UV-LEDs at peak emission wavelengths of 265, 280, and 300 nm were adopted to inactivate pathogenic species, including Pseudomonas aeruginosa and Legionella pneumophila, and surrogate species, including Escherichia coli, Bacillus subtilis spores, and bacteriophage Qβ in water, compared to conventional low-pressure UV lamp emitting at 254 nm. The inactivation profiles of each species showed either a linear or sigmoidal survival curve, which both fit well with the Geeraerd's model. Based on the inactivation rate constant, the 265-nm UV-LED showed most effective fluence, except for with E. coli which showed similar inactivation rates at 265 and 254 nm. Electrical energy consumption required for 3-log 10 inactivation (E E,3 ) was lowest for the 280-nm UV-LED for all microbial species tested. Taken together, the findings of this study determined the inactivation profiles and kinetics of both pathogenic bacteria and surrogate species under UV-LED exposure at different wavelengths. We also demonstrated that not only inactivation rate constants, but also energy efficiency should be considered when selecting an emission wavelength for UV-LEDs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Radiation inactivation of T7 phage

International Nuclear Information System (INIS)

Becker, D.; Redpath, J.L.; Grossweiner, L.I.

1978-01-01

The radiation inactivation of T7 phage by 25-MeV electron pulses has been measured in various media containing a wide concentration range of radical scavenging solutes and in the presence of protective and sensitizing agents. The dependence of sensitivity on pulse dose, from 1 mrad to 3.6 krad, is attributed to radical depletion via bimolecular processes. The survival data are analyzed by extending target theory to include diffusive reactions of primary and secondary radicals generated in the medium. It is concluded that OH radicals are the principal primary inactivating species and that secondary radicals from Br - , CNS - , uracil, glucose, ribose, sucrose, tyrosine, and histidine are lethal to some extent. In nutrient broth or 100 mM histidine, psoralen derivatives, Actinomycin D, and Mitomycin C are anoxic sensitizers. It is proposed that the psoralens promote the formation of non-strand break lesions as the sensitization mechanism. The target theory based on diffusional kinetics is applicable to other systems including single cells

X-chromosome inactivation in development and cancer.

Science.gov (United States)

Chaligné, Ronan; Heard, Edith

2014-08-01

X-chromosome inactivation represents an epigenetics paradigm and a powerful model system of facultative heterochromatin formation triggered by a non-coding RNA, Xist, during development. Once established, the inactive state of the Xi is highly stable in somatic cells, thanks to a combination of chromatin associated proteins, DNA methylation and nuclear organization. However, sporadic reactivation of X-linked genes has been reported during ageing and in transformed cells and disappearance of the Barr body is frequently observed in cancer cells. In this review we summarise current knowledge on the epigenetic changes that accompany X inactivation and discuss the extent to which the inactive X chromosome may be epigenetically or genetically perturbed in breast cancer. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Effective Thermal Inactivation of the Spores of Bacillus cereus Biofilms Using Microwave.

Science.gov (United States)

Park, Hyong Seok; Yang, Jungwoo; Choi, Hee Jung; Kim, Kyoung Heon

2017-07-28

Microwave sterilization was performed to inactivate the spores of biofilms of Bacillus cereus involved in foodborne illness. The sterilization conditions, such as the amount of water and the operating temperature and treatment time, were optimized using statistical analysis based on 15 runs of experimental results designed by the Box-Behnken method. Statistical analysis showed that the optimal conditions for the inactivation of B. cereus biofilms were 14 ml of water, 108°C of temperature, and 15 min of treatment time. Interestingly, response surface plots showed that the amount of water is the most important factor for microwave sterilization under the present conditions. Complete inactivation by microwaves was achieved in 5 min, and the inactivation efficiency by microwave was obviously higher than that by conventional steam autoclave. Finally, confocal laser scanning microscopy images showed that the principal effect of microwave treatment was cell membrane disruption. Thus, this study can contribute to the development of a process to control food-associated pathogens.

ALTERNATIVE EQUATIONS FOR DYNAMIC BEHAVIOR OF IONIC CHANNEL ACTIVATION AND INACTIVATION GATES

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Mahmut ÖZER

2003-03-01

Full Text Available In this paper, alternative equations for dynamics of ionic channel activation and inactivation gates are proposed based on the path probability method. Dynamic behavior of a voltage-gated ionic channel is modeled by the conventional Hodgkin-Huxley (H-H mathematical formalism. In that model, conductance of the channel is defined in terms of activation and inactivation gates. Dynamics of the activation and inactivation gates is modeled by first-order differential equations dependent on the gate variable and the membrane potential. In the new approach proposed in this study, dynamic behavior of activation and inactivation gates is modeled by a firstorder differential equation dependent on internal energy and membrane potential by using the path probability method which is widely used in statistical physics. The new model doesn't require the time constant and steadystate values which are used explicitly in the H-H model. The numerical results show validity of the proposed method.

Modeling of human factor Va inactivation by activated protein C

Directory of Open Access Journals (Sweden)

Bravo Maria

2012-05-01

Full Text Available Abstract Background Because understanding of the inventory, connectivity and dynamics of the components characterizing the process of coagulation is relatively mature, it has become an attractive target for physiochemical modeling. Such models can potentially improve the design of therapeutics. The prothrombinase complex (composed of the protease factor (FXa and its cofactor FVa plays a central role in this network as the main producer of thrombin, which catalyses both the activation of platelets and the conversion of fibrinogen to fibrin, the main substances of a clot. A key negative feedback loop that prevents clot propagation beyond the site of injury is the thrombin-dependent generation of activated protein C (APC, an enzyme that inactivates FVa, thus neutralizing the prothrombinase complex. APC inactivation of FVa is complex, involving the production of partially active intermediates and “protection” of FVa from APC by both FXa and prothrombin. An empirically validated mathematical model of this process would be useful in advancing the predictive capacity of comprehensive models of coagulation. Results A model of human APC inactivation of prothrombinase was constructed in a stepwise fashion by analyzing time courses of FVa inactivation in empirical reaction systems with increasing number of interacting components and generating corresponding model constructs of each reaction system. Reaction mechanisms, rate constants and equilibrium constants informing these model constructs were initially derived from various research groups reporting on APC inactivation of FVa in isolation, or in the presence of FXa or prothrombin. Model predictions were assessed against empirical data measuring the appearance and disappearance of multiple FVa degradation intermediates as well as prothrombinase activity changes, with plasma proteins derived from multiple preparations. Our work integrates previously published findings and through the cooperative

Inactivation of Bacillus spores inoculated in milk by Ultra High Pressure Homogenization.

Science.gov (United States)

Amador Espejo, Genaro Gustavo; Hernández-Herrero, M M; Juan, B; Trujillo, A J

2014-12-01

Ultra High-Pressure Homogenization treatments at 300 MPa with inlet temperatures (Ti) of 55, 65, 75 and 85 °C were applied to commercial Ultra High Temperature treated whole milk inoculated with Bacillus cereus, Bacillus licheniformis, Bacillus sporothermodurans, Bacillus coagulans, Geobacillus stearothermophilus and Bacillus subtilis spores in order to evaluate the inactivation level achieved. Ultra High-Pressure Homogenization conditions at 300 MPa with Ti = 75 and 85 °C were capable of a spore inactivation of ∼5 log CFU/mL. Furthermore, under these processing conditions, commercial sterility (evaluated as the complete inactivation of the inoculated spores) was obtained in milk, with the exception of G. stearothermophilus and B. subtilis treated at 300 MPa with Ti = 75 °C. The results showed that G. stearothermophilus and B. subtilis have higher resistance to the Ultra High-Pressure Homogenization treatments applied than the other microorganisms inoculated and that a treatment performed at 300 MPa with Ti = 85 °C was necessary to completely inactivate these microorganisms at the spore level inoculated (∼1 × 10(6) CFU/mL). Besides, a change in the resistance of B. licheniformis, B. sporothermodurans, G. stearothermophilus and B. subtilis spores was observed as the inactivation obtained increased remarkably in treatments performed with Ti between 65 and 75 °C. This study provides important evidence of the suitability of UHPH technology for the inactivation of spores in high numbers, leading to the possibility of obtaining commercially sterile milk. Copyright © 2014 Elsevier Ltd. All rights reserved.

The adjuvanticity of ophiopogon polysaccharide liposome against an inactivated porcine parvovirus vaccine in mice.

Science.gov (United States)

Fan, Yunpeng; Ma, Xia; Hou, Weifeng; Guo, Chao; Zhang, Jing; Zhang, Weimin; Ma, Lin; Song, Xiaoping

2016-01-01

In this study, the adjuvant activity of ophiopogon polysaccharide liposome (OPL) was investigated. The effects of OPL on the splenic lymphocyte proliferation of mice were measured in vitro. The results showed that OPL could significantly promote lymphocyte proliferation singly or synergistically with PHA and LPS and that the effect was better than ophiopogon polysaccharide (OP) at most of concentrations. The adjuvant activities of OPL, OP and mineral oil were compared in BALB/c mice inoculated with inactivated PPV in vivo. The results showed that OPL could significantly enhance lymphocyte proliferation, increase the proportion of CD4(+) and CD8(+) T cells, improve the HI antibody titre and specific IgG response, and promote the production of cytokines, and the efficacy of OPL was significantly better than that of OP. In addition, OPL significantly improved the cellular immune response compared with oil adjuvant. These results suggested that OPL possess superior adjuvanticity and that a medium dose had the best efficacy. Therefore, OPL can be used as an effective immune adjuvant for an inactivated PPV vaccine. Copyright © 2015. Published by Elsevier B.V.

Inactivation of carotenoid-producing and albino strains of Neurospora crassa by visible light, blacklight, and ultraviolet radiation

International Nuclear Information System (INIS)

Blanc, P.L.; Tuveson, R.W.; Sargent, M.L.

1976-01-01

Suspensions of Neurospora crassa conidia were inactivated by blacklight (BL) radiation (300 to 425 nm) in the absence of exogenous photosensitizing compounds. Carotenoid-containing wild-type conidia were less sensitive to BL radiation than albino conidia, showing a dose enhancement factor (DEF) of 1.2 for dose levels resulting in less than 10 percent survival. The same strains were about equally sensitive to shortwave ultraviolet (uv) inactivation. The kinetics of BL inactivation are similar to those of photodynamic inactivation by visible light in the presence of a photosensitizing dye (methylene blue). Only limited inactivation by visible light in the absence of exogenous photosensitizers was observed. BL and UV inactivations are probably caused by different mechanisms since wild-type conidia are only slightly more resistant to BL radiation (DEF = 1.2 at 1.0 percent survival) than are conidia from a uv-sensitive strain (upr-1, uvs-3). The BL-induced lethal lesions are probably not cyclobutyl pyrimidine dimers since BL-inactivated Haemophilus influenzae transforming deoxyribonucleic acid is not photoreactivated by N. crassa wild-type enzyme extracts, whereas uv-inactivated transforming deoxyribonucleic acid is photoreactivable with this treatment

Inactivation of Listeria monocytogenes in milk by pulsed electric field.

Science.gov (United States)

Reina, L D; Jin, Z T; Zhang, Q H; Yousef, A E

1998-09-01

Pasteurized whole, 2%, and skim milk were inoculated with Listeria monocytogenes Scott A and treated with high-voltage pulsed electric field (PEF). The effects of milk composition (fat content) and PEF parameters (electric field strength, treatment time, and treatment temperature) on the inactivation of the bacterium were studied. No significant differences were observed in the inactivation of L. monocytogenes Scott A in three types of milk by PEF treatment. With treatment at 25 degrees C, 1- to 3-log reductions of L. monocytogenes were observed. PEF lethal effect was a function of field strength and treatment time. Higher field strength or longer treatment time resulted in a greater reduction of viable cells. A 4-log reduction of the bacterium was obtained by increasing the treatment temperature to 50 degrees C. Results indicate that the use of a high-voltage PEF is a promising technology for inactivation of foodborne pathogens.

Synergistic inactivation of anaerobic wastewater biofilm by free nitrous acid and hydrogen peroxide

International Nuclear Information System (INIS)

Jiang, Guangming; Yuan, Zhiguo

2013-01-01

Highlights: ► H 2 O 2 greatly enhances the inactivation of microorganisms in biofilms by FNA. ► About 2-log of inactivation of biofilm microbes was achieved by FNA + H 2 O 2 . ► FNA + H 2 O 2 reduced sulfide production and detached biofilm in reactors. -- Abstract: Free nitrous acid (FNA) was recently revealed to be a strong biocide for microbes in anaerobic biofilm, achieving approximately 1-log (90%) inactivation at a concentration of 0.2–0.3 mgHNO 2 -N/L with an exposure time longer than 6 h. The combined biocidal effects of FNA and hydrogen peroxide (H 2 O 2 ) on anaerobic wastewater biofilm are investigated in this study. H 2 O 2 greatly enhances the inactivation of microorganisms by FNA. About 2-log (99%) of microbial inactivation was achieved when biofilms were exposed to FNA at 0.2 mgN/L or above and H 2 O 2 at 30 mg/L or above for 6 h or longer. It was found, through response surface methodology and ridge analysis, that FNA is the primary inactivation agent and H 2 O 2 enhances its efficiency. The loss and the subsequent slow recovery of biological activity in biofilm reactors subjected to FNA and H 2 O 2 dosing confirmed that the chemical combination could achieve higher microbial inactivation than with FNA alone. Reaction simulation shows that intermediates of reactions between FNA and H 2 O 2 , like peroxynitrite and nitrogen dioxide, would be produced at elevated levels and are likely responsible for the synergism between FNA and H 2 O 2 . The combination of FNA and H 2 O 2 could potentially provide an effective solution to sewer biofilm control

Synergistic inactivation of anaerobic wastewater biofilm by free nitrous acid and hydrogen peroxide

Energy Technology Data Exchange (ETDEWEB)

Jiang, Guangming, E-mail: gjiang@awmc.uq.edu.au [Advanced Water Management Centre, Gehrmann Building, Research Road, The University of Queensland, St. Lucia, Queensland 4072 (Australia); Yuan, Zhiguo, E-mail: zhiguo@awmc.uq.edu.au [Advanced Water Management Centre, Gehrmann Building, Research Road, The University of Queensland, St. Lucia, Queensland 4072 (Australia)

2013-04-15

Highlights: ► H{sub 2}O{sub 2} greatly enhances the inactivation of microorganisms in biofilms by FNA. ► About 2-log of inactivation of biofilm microbes was achieved by FNA + H{sub 2}O{sub 2}. ► FNA + H{sub 2}O{sub 2} reduced sulfide production and detached biofilm in reactors. -- Abstract: Free nitrous acid (FNA) was recently revealed to be a strong biocide for microbes in anaerobic biofilm, achieving approximately 1-log (90%) inactivation at a concentration of 0.2–0.3 mgHNO{sub 2}-N/L with an exposure time longer than 6 h. The combined biocidal effects of FNA and hydrogen peroxide (H{sub 2}O{sub 2}) on anaerobic wastewater biofilm are investigated in this study. H{sub 2}O{sub 2} greatly enhances the inactivation of microorganisms by FNA. About 2-log (99%) of microbial inactivation was achieved when biofilms were exposed to FNA at 0.2 mgN/L or above and H{sub 2}O{sub 2} at 30 mg/L or above for 6 h or longer. It was found, through response surface methodology and ridge analysis, that FNA is the primary inactivation agent and H{sub 2}O{sub 2} enhances its efficiency. The loss and the subsequent slow recovery of biological activity in biofilm reactors subjected to FNA and H{sub 2}O{sub 2} dosing confirmed that the chemical combination could achieve higher microbial inactivation than with FNA alone. Reaction simulation shows that intermediates of reactions between FNA and H{sub 2}O{sub 2}, like peroxynitrite and nitrogen dioxide, would be produced at elevated levels and are likely responsible for the synergism between FNA and H{sub 2}O{sub 2}. The combination of FNA and H{sub 2}O{sub 2} could potentially provide an effective solution to sewer biofilm control.

Reactive hydroxyl radical-driven oral bacterial inactivation by radio frequency atmospheric plasma

International Nuclear Information System (INIS)

Kang, Sung Kil; Lee, Jae Koo; Choi, Myeong Yeol; Koo, Il Gyo; Kim, Paul Y.; Kim, Yoonsun; Kim, Gon Jun; Collins, George J.; Mohamed, Abdel-Aleam H.

2011-01-01

We demonstrated bacterial (Streptococcus mutans) inactivation by a radio frequency power driven atmospheric pressure plasma torch with H 2 O 2 entrained in the feedstock gas. Optical emission spectroscopy identified substantial excited state OH generation inside the plasma and relative OH formation was verified by optical absorption. The bacterial inactivation rate increased with increasing OH generation and reached a maximum 5-log 10 reduction with 0.6%H 2 O 2 vapor. Generation of large amounts of toxic ozone is drawback of plasma bacterial inactivation, thus it is significant that the ozone concentration falls within recommended safe allowable levels with addition of H 2 O 2 vapor to the plasma.

The inactivating and mutagenic effect of hydroxylamine on bacteriophage φX174

NARCIS (Netherlands)

Pol, J.H. van de; Arkel, G.A. van

1965-01-01

The inactivation of bacteriophage ΦXI74 by the mutagenic agents nitrous acid and ultraviolet irradiation proceeds according to a single-hit kinetics. However, treatment of purified ΦXI74 by hydroxylamine (HA) at pH 6 and 25° results in an inactivation that is not strictly exponential. The

Radiation-induced inactivation of bovine liver catalase in nitrous oxide-saturated solutions

International Nuclear Information System (INIS)

Gebicka, L.; Metodiewa, D.

1988-01-01

Radiation-induced inactivation of catalase by . OH/H . radicals was studied. It was found that inactivation yield of catalase depended on the dose. Optical spectrum of irradiated catalase showed that no redox processes in active site of enzyme occurred as a result of . OH/H . interaction. (author) 19 refs.; 3 figs

Enhanced vulnerability of human proteins towards disease-associated inactivation through divergent evolution.

Science.gov (United States)

Medina-Carmona, Encarnación; Fuchs, Julian E; Gavira, Jose A; Mesa-Torres, Noel; Neira, Jose L; Salido, Eduardo; Palomino-Morales, Rogelio; Burgos, Miguel; Timson, David J; Pey, Angel L

2017-09-15

Human proteins are vulnerable towards disease-associated single amino acid replacements affecting protein stability and function. Interestingly, a few studies have shown that consensus amino acids from mammals or vertebrates can enhance protein stability when incorporated into human proteins. Here, we investigate yet unexplored relationships between the high vulnerability of human proteins towards disease-associated inactivation and recent evolutionary site-specific divergence of stabilizing amino acids. Using phylogenetic, structural and experimental analyses, we show that divergence from the consensus amino acids at several sites during mammalian evolution has caused local protein destabilization in two human proteins linked to disease: cancer-associated NQO1 and alanine:glyoxylate aminotransferase, mutated in primary hyperoxaluria type I. We demonstrate that a single consensus mutation (H80R) acts as a disease suppressor on the most common cancer-associated polymorphism in NQO1 (P187S). The H80R mutation reactivates P187S by enhancing FAD binding affinity through local and dynamic stabilization of its binding site. Furthermore, we show how a second suppressor mutation (E247Q) cooperates with H80R in protecting the P187S polymorphism towards inactivation through long-range allosteric communication within the structural ensemble of the protein. Our results support that recent divergence of consensus amino acids may have occurred with neutral effects on many functional and regulatory traits of wild-type human proteins. However, divergence at certain sites may have increased the propensity of some human proteins towards inactivation due to disease-associated mutations and polymorphisms. Consensus mutations also emerge as a potential strategy to identify structural hot-spots in proteins as targets for pharmacological rescue in loss-of-function genetic diseases. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please

Electron beam inactivation of Tulane virus on fresh produce, and mechanism of inactivation of human norovirus surrogates by electron beam irradiation.

Science.gov (United States)

Predmore, Ashley; Sanglay, Gabriel C; DiCaprio, Erin; Li, Jianrong; Uribe, R M; Lee, Ken

2015-04-02

Ionizing radiation, whether by electron beams or gamma rays, is a non-thermal processing technique used to improve the microbial safety and shelf-life of many different food products. This technology is highly effective against bacterial pathogens, but data on its effect against foodborne viruses is limited. A mechanism of viral inactivation has been proposed with gamma irradiation, but no published study discloses a mechanism for electron beam (e-beam). This study had three distinct goals: 1) evaluate the sensitivity of a human norovirus surrogate, Tulane virus (TV), to e-beam irradiation in foods, 2) compare the difference in sensitivity of TV and murine norovirus (MNV-1) to e-beam irradiation, and 3) determine the mechanism of inactivation of these two viruses by e-beam irradiation. TV was reduced from 7 log10 units to undetectable levels at target doses of 16 kGy or higher in two food matrices (strawberries and lettuce). MNV-1 was more resistant to e-beam treatment than TV. At target doses of 4 kGy, e-beam provided a 1.6 and 1.2 log reduction of MNV-1 in phosphate buffered saline (PBS) and Dulbecco's Modified Eagle Medium (DMEM), compared to a 1.5 and 1.8 log reduction of TV in PBS and Opti-MEM, respectively. Transmission electron microscopy revealed that increased e-beam doses negatively affected the structure of both viruses. Analysis of viral proteins by SDS-PAGE found that irradiation also degraded viral proteins. Using RT-PCR, irradiation was shown to degrade viral genomic RNA. This suggests that the mechanism of inactivation of e-beam was likely the same as gamma irradiation as the damage to viral constituents led to inactivation. Copyright © 2014 Elsevier B.V. All rights reserved.

Inhibition of host cell protein synthesis by UV-inactivated poliovirus

International Nuclear Information System (INIS)

Helentjaris, T.; Ehrenfeld, E.

1977-01-01

The ability of poliovirus that was irradiated with UV light at energies up to 2,160 ergs/mm 2 to subsequently inhibit host cell protein synthesis was measured. The inactivation of the host cell shutoff function followed one-hit kinetics. Increasing irradiation did not affect the rate of inhibition until the multiplicity of infection after irradiation was reduced to approximately 1 PFU/cell. At higher functional multiplicities, the rate was unchanged, but an increasing lag before the onset of inhibition was observed with increasing irradiation. The energy levels required to inactivate virus-induced inhibition of host cell protein synthesis suggest that damage to virus RNA rather than to virus capsid proteins is responsible for the loss of function. When the inactivation of host cell shutoff was compared with the inactivation of other viral functions by UV irradiation, it correlated exactly with the loss of infectivity but not with other viral functions measured. Guanidine treatment, which prevents detectable viral RNA and protein synthesis, completely inhibited host cell shutoff by low multiplicities of unirradiated virus infection but not higher multiplicities. When a high multiplicity of virus was first reduced to a low titer by irradiation, host cell shutoff was still evident in the presence of guanidine. The results demonstrate that the complete inhibition of host cell protein synthesis can be accomplished by one infectious viral genome per cell

Inactivation of human norovirus using chemical sanitizers.

Science.gov (United States)

Kingsley, David H; Vincent, Emily M; Meade, Gloria K; Watson, Clytrice L; Fan, Xuetong

2014-02-03

The porcine gastric mucin binding magnetic bead (PGM-MB) assay was used to evaluate the ability of chlorine, chlorine dioxide, peroxyacetic acid, hydrogen peroxide, and trisodium phosphate to inactivate human norovirus within 10% stool filtrate. One-minute free chlorine treatments at concentrations of 33 and 189 ppm reduced virus binding in the PGM-MB assay by 1.48 and 4.14 log₁₀, respectively, suggesting that chlorine is an efficient sanitizer for inactivation of human norovirus (HuNoV). Five minute treatments with 5% trisodium phosphate (pH~12) reduced HuNoV binding by 1.6 log₁₀, suggesting that TSP, or some other high pH buffer, could be used to treat food and food contact surfaces to reduce HuNoV. One minute treatments with 350 ppm chlorine dioxide dissolved in water did not reduce PGM-MB binding, suggesting that the sanitizer may not be suitable for HuNoV inactivation in liquid form. However a 60-min treatment with 350 ppm chlorine dioxide did reduce human norovirus by 2.8 log₁₀, indicating that chlorine dioxide had some, albeit limited, activity against HuNoV. Results also suggest that peroxyacetic acid has limited effectiveness against human norovirus, since 1-min treatments with up to 195 ppm reduced human norovirus binding by chlorine (sodium hypochlorite) as a HuNoV disinfectant wherever possible. Copyright © 2013. Published by Elsevier B.V.

Immunization against chlamydial genital infection in guinea pigs with UV-inactivated and viable chlamydiae administered by different routes

International Nuclear Information System (INIS)

Rank, R.G.; Batteiger, B.E.; Soderberg, L.S.

1990-01-01

Female guinea pigs were immunized with viable or UV light-inactivated chlamydiae, belonging to the species Chlamydia psittaci, by intravenous, subcutaneous, oral, or ocular routes. All animals were then inoculated vaginally with viable chlamydiae to determine the extent of protection against challenge infection induced by the various regimens. The course of genital infection was significantly reduced in intensity in all groups of animals except the unimmunized controls and those animals immunized orally with inactivated antigen. Guinea pigs immunized with viable antigen were more likely to develop resistance to challenge infection and, in general, had a significantly greater degree of protection than animals immunized with inactivated antigen. No one route seemed superior in producing a protective response. Animals in all groups demonstrating protection developed serum and secretion immunoglobulin G antibody responses to chlamydiae. Lymphocyte proliferative reactions to chlamydial antigen were variable among groups. Immunoblot analysis of serum and secretions indicated a wide range of antibody specificities, but most protected animals produced antibodies to the major outer membrane protein, lipopolysaccharide, and the 61-kilodalton protein. No definitive associations could be made between the increased ability of immunization with viable organisms to produce resistance to challenge infection and a particular immune parameter. These data indicate that viable chlamydiae given by various routes are able to induce a strong immune response which can provide resistance against reinfection in some cases or at least reduce the degree of infection to a greater degree than inactivated antigen. However, complete resistance to genital tract infection may be difficult to obtain and alternate immunizations strategies may have to be developed

Pulsed-light inactivation of pathogenic and spoilage bacteria on cheese surface.

Science.gov (United States)

Proulx, J; Hsu, L C; Miller, B M; Sullivan, G; Paradis, K; Moraru, C I

2015-09-01

Cheese products are susceptible to postprocessing cross-contamination by bacterial surface contamination during slicing, handling, or packaging, which can lead to food safety issues and significant losses due to spoilage. This study examined the effectiveness of pulsed-light (PL) treatment on the inactivation of the spoilage microorganism Pseudomonas fluorescens, the nonenterohemorrhagic Escherichia coli ATCC 25922 (nonpathogenic surrogate of Escherichia coli O157:H7), and Listeria innocua (nonpathogenic surrogate of Listeria monocytogenes) on cheese surface. The effects of inoculum level and cheese surface topography and the presence of clear polyethylene packaging were evaluated in a full factorial experimental design. The challenge microorganisms were grown to early stationary phase and subsequently diluted to reach initial inoculum levels of either 5 or 7 log cfu/slice. White Cheddar and process cheeses were cut into 2.5×5 cm slices, which were spot-inoculated with 100 µL of bacterial suspension. Inoculated cheese samples were exposed to PL doses of 1.02 to 12.29 J/cm(2). Recovered survivors were enumerated by standard plate counting or the most probable number technique, as appropriate. The PL treatments were performed in triplicate and data were analyzed using a general linear model. Listeria innocua was the least sensitive to PL treatment, with a maximum inactivation level of 3.37±0.2 log, followed by P. fluorescens, with a maximum inactivation of 3.74±0.8 log. Escherichia coli was the most sensitive to PL, with a maximum reduction of 5.41±0.1 log. All PL inactivation curves were nonlinear, and inactivation reached a plateau after 3 pulses (3.07 J/cm(2)). The PL treatments through UV-transparent packaging and without packaging consistently resulted in similar inactivation levels. This study demonstrates that PL has strong potential for decontamination of the cheese surface. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc

Singlet oxygen treatment of tumor cells triggers extracellular singlet oxygen generation, catalase inactivation and reactivation of intercellular apoptosis-inducing signaling.

Science.gov (United States)

Riethmüller, Michaela; Burger, Nils; Bauer, Georg

2015-12-01

Intracellular singlet oxygen generation in photofrin-loaded cells caused cell death without discrimination between nonmalignant and malignant cells. In contrast, extracellular singlet oxygen generation caused apoptosis induction selectively in tumor cells through singlet oxygen-mediated inactivation of tumor cell protective catalase and subsequent reactivation of intercellular ROS-mediated apoptosis signaling through the HOCl and the NO/peroxynitrite signaling pathway. Singlet oxygen generation by extracellular photofrin alone was, however, not sufficient for optimal direct inactivation of catalase, but needed to trigger the generation of cell-derived extracellular singlet oxygen through the interaction between H2O2 and peroxynitrite. Thereby, formation of peroxynitrous acid, generation of hydroxyl radicals and formation of perhydroxyl radicals (HO2(.)) through hydroxyl radical/H2O2 interaction seemed to be required as intermediate steps. This amplificatory mechanism led to the formation of singlet oxygen at a sufficiently high concentration for optimal inactivation of membrane-associated catalase. At low initial concentrations of singlet oxygen, an additional amplification step needed to be activated. It depended on singlet oxygen-dependent activation of the FAS receptor and caspase-8, followed by caspase-8-mediated enhancement of NOX activity. The biochemical mechanisms described here might be considered as promising principle for the development of novel approaches in tumor therapy that specifically direct membrane-associated catalase of tumor cells and thus utilize tumor cell-specific apoptosis-inducing ROS signaling. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Short communication: Pasteurization as a means of inactivating staphylococcal enterotoxins A, B, and C in milk.

Science.gov (United States)

Necidova, Lenka; Bogdanovicova, Katerina; Harustiakova, Danka; Bartova, Katerina

2016-11-01

Our aim was to assess the effect of pasteurization temperature on inactivation of staphylococcal enterotoxins (SE). Milk samples were inoculated with log 4.38 to 5.18cfu/mL of 40 different Staphylococcus aureus strains having the ability to produce types A, B, or C SE and incubated at 37°C for 24h to develop SE. This incubation was followed by heat treatment for 15 s at 72, 85, and 92°C. Samples were analyzed for Staph. aureus count by plate method and, specifically, for SE presence. An enzyme-linked immunofluorescent assay on a MiniVIDAS analyzer (bioMérieux, Marcy l'Étoile, France) was used to detect SE, which were determined semiquantitatively based on test values. The Staph. aureus count in milk before pasteurization did not affect the amount of SE. Before pasteurization, SEB was detected in the lowest amount compared with other SE types. Staphylococcal enterotoxins were markedly reduced with pasteurization and inactivated at pasteurization temperatures to an extent depending on the amount in the sample before pasteurization. After pasteurization at 72°C, SE were detected in 87.5% of samples (35/40), after pasteurization at 85°C in 52.5% of samples (21/40), and after pasteurization at 92°C in 45.0% of samples (18/40). We determined that SE may still persist in milk even when Staph. aureus bacteria are inactivated through pasteurization. Although pasteurization may partially inactivate SE in milk, a key measure in the prevention of staphylococcal enterotoxicosis linked to pasteurized milk consumption is to avoid any cold chain disruption during milk production and processing. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Effect of constitutive inactivation of the myostatin gene on the gain in muscle strength during postnatal growth in two murine models.

Science.gov (United States)

Stantzou, Amalia; Ueberschlag-Pitiot, Vanessa; Thomasson, Remi; Furling, Denis; Bonnieu, Anne; Amthor, Helge; Ferry, Arnaud

2017-02-01

The effect of constitutive inactivation of the gene encoding myostatin on the gain in muscle performance during postnatal growth has not been well characterized. We analyzed 2 murine myostatin knockout (KO) models, (i) the Lee model (KO Lee ) and (ii) the Grobet model (KO Grobet ), and measured the contraction of tibialis anterior muscle in situ. Absolute maximal isometric force was increased in 6-month-old KO Lee and KO Grobet mice, as compared to wild-type mice. Similarly, absolute maximal power was increased in 6-month-old KO Lee mice. In contrast, specific maximal force (relative maximal force per unit of muscle mass was decreased in all 6-month-old male and female KO mice, except in 6-month-old female KO Grobet mice, whereas specific maximal power was reduced only in male KO Lee mice. Genetic inactivation of myostatin increases maximal force and power, but in return it reduces muscle quality, particularly in male mice. Muscle Nerve 55: 254-261, 2017. © 2016 Wiley Periodicals, Inc.

MPLEx: a method for simultaneous pathogen inactivation and extraction of samples for multi-omics profiling

Energy Technology Data Exchange (ETDEWEB)

Burnum-Johnson, Kristin E.; Kyle, Jennifer E.; Eisfeld, Amie J.; Casey, Cameron P.; Stratton, Kelly G.; Gonzalez, Juan F.; Habyarimana, Fabien; Negretti, Nicholas M.; Sims, Amy C.; Chauhan, Sadhana; Thackray, Larissa B.; Halfmann, Peter J.; Walters, Kevin B.; Kim, Young-Mo; Zink, Erika M.; Nicora, Carrie D.; Weitz, Karl K.; Webb-Robertson, Bobbie-Jo M.; Nakayasu, Ernesto S.; Ahmer, Brian; Konkel, Michael E.; Motin, Vladimir; Baric, Ralph S.; Diamond, Michael S.; Kawaoka, Yoshihiro; Waters, Katrina M.; Smith, Richard D.; Metz, Thomas O.

2017-01-01

The continued emergence and spread of infectious agents is of increasing concern due to increased population growth and the associated increased livestock production to meet food demands, increased urbanization and land-use changes, and greater travel. A systems biology approach to infectious disease research can significantly advance our understanding of host-pathogen relationships and facilitate the development of new therapies and vaccines. Molecular characterization of infectious samples outside of appropriate biosafety containment can only take place subsequent to pathogen inactivation. Herein, we describe a modified Folch extraction using chloroform/methanol that facilitates the molecular characterization of infectious samples by enabling simultaneous pathogen inactivation and extraction of proteins, metabolites, and lipids for subsequent mass spectrometry-based multi-omics measurements. This metabolite, protein and lipid extraction (MPLEx) method resulted in complete inactivation of bacterial and viral pathogens with exposed lipid membranes, including Yersinia pestis, Salmonella Typhimurium, and Campylobacter jejuni in pure culture, and Yersinia pestis, Campylobacter jejuni, West Nile, MERS-CoV, Ebola, and influenza H7N9 viruses in infection studies. Partial inactivation was observed for pathogens without exposed lipid membranes including 99.99% inactivation of community-associated methicillin-resistant Staphylococcus aureus, 99.6% and >99% inactivation of Clostridium difficile spores and vegetative cells, respectively, and 50% inactivation of adenovirus type 5. To demonstrate that MPLEx yields biomaterial of sufficient quality for subsequent multi-omics analyses, we highlight select proteomics, metabolomics and lipidomics data from human epithelial lung cells infected with wild-type and mutant forms of influenza H7N9. We believe that MPLEx will facilitate systems biology studies of infectious samples by enabling simultaneous pathogen inactivation and multi

Inactivation of Listeria innocua in skim milk by pulsed electric fields and nisin.

Science.gov (United States)

Calderón-Miranda, M L; Barbosa-Cánovas, G V; Swanson, B G

1999-10-01

Pulsed electric fields (PEF) is an emerging nonthermal processing technology used to inactivate microorganisms in liquid foods such as milk. PEF results in loss of cell membrane functionality that leads to inactivation of the microorganism. There are many processes that aid in the stability and safety of foods. The combination of different preservation factors, such as nisin and PEF, to control microorganisms should be explored. The objective of this research was to study the inactivation of Listeria innocua suspended in skim milk by PEF as well as the sensitization of PEF treated L. innocua to nisin. The selected electric field intensity was 30, 40 and 50 kV/cm and the number of pulses applied was 10.6, 21.3 and 32. The sensitization exhibited by PEF treated L. innocua to nisin was assessed for 10 or 100 IU nisin/ml. A progressive decrease in the population of L. innocua was observed for the selected field intensities, with the greatest reduction being 2 1/2 log cycles (U). The exposure of L. innocua to nisin after PEF had an additive effect on the inactivation of the microorganism as that exhibited by the PEF alone. As the electric field, number of pulses and nisin concentration increased, synergism was observed in the inactivation of L. innocua as a result of exposure to nisin after PEF. The reduction of L. innocua accomplished by exposure to 10 IU nisin/ml after 32 pulsed electric fields was 2, 2.7, and 3.4 U for an electric field intensity of 30, 40, and 50 kV/cm, respectively. Population of L. innocua subjected to 100 IU nisin/ml after PEF was 2.8-3.8 U for the selected electric field intensities and 32 pulses. The designed model for the inactivation of L. innocua as a result of the PEF followed by exposure to nisin proved to be accurate in the prediction of the inactivation of L. innocua in skim milk containing 1.2 or 37 IU nisin/ml. Inactivation of L. innocua in skim milk containing 37 IU nisin/ml resulted in a decrease in population of 3.7 U.

Inactivation of STAT3 Signaling Impairs Hair Cell Differentiation in the Developing Mouse Cochlea.

Science.gov (United States)

Chen, Qianqian; Quan, Yizhou; Wang, Naitao; Xie, Chengying; Ji, Zhongzhong; He, Hao; Chai, Renjie; Li, Huawei; Yin, Shankai; Chin, Y Eugene; Wei, Xunbin; Gao, Wei-Qiang

2017-07-11

Although STAT3 signaling is demonstrated to regulate sensory cell differentiation and regeneration in the zebrafish, its exact role is still unclear in mammalian cochleae. Here, we report that STAT3 and its activated form are specifically expressed in hair cells during mouse cochlear development. Importantly, conditional cochlear deletion of Stat3 leads to an inhibition on hair cell differentiation in mice in vivo and in vitro. By cell fate analysis, inactivation of STAT3 signaling shifts the cell division modes from asymmetric to symmetric divisions from supporting cells. Moreover, inhibition of Notch signaling stimulates STAT3 phosphorylation, and inactivation of STAT3 signaling attenuates production of supernumerary hair cells induced by a Notch pathway inhibitor. Our findings highlight an important role of the STAT3 signaling during mouse cochlear hair cell differentiation and may have clinical implications for the recovery of hair cell loss-induced hearing impairment. Copyright © 2017 International Society for Stem Cell Research. Published by Elsevier Inc. All rights reserved.

Comparative study of methods for inactivation of vaccines on development process of veterinary “Ghost” vaccine

International Nuclear Information System (INIS)

Pencheva, Daniela; Genova-Kalou, Petia; Bryaskova, Rayna

2016-01-01

Experimental and laboratory tests were carried out in order to identify the advantages of “ghost” antigens obtained by treatment of the bacterial cell with silver nanoparticles in comparison to the inactivated antigens obtained by classical methods as heating or treatment with formalin. The Minimal Bactericidal Concentrations (MBC) of the hybrid material containing silver nanoparticles (PVA/AgNps), used for inactivation of the tested E. coli strains were determined and they were categorized as susceptible to the action of silver nanoparticles. The changes in the structure of the bacterial cells obtained after the treatment with the hybrid material containing silver nanoparticles or with formaldehyde, respectively, were established by TEM (Transmission electron microscopy) analysis. The advantages of the “ghost” vaccines are expressed in undamaged cell wall and better immunogenicity, thus resulting in faster formation of specific titer after immunization of experimental animals. Key words: E. coli O149, E. coli O157H7, “ghost” vaccine, silver nanoparticles, TEM

Protection against avian metapneumovirus subtype C in turkeys immunized via the respiratory tract with inactivated virus.

Science.gov (United States)

Cha, Ra Mi; Khatri, Mahesh; Sharma, Jagdev M

2011-01-10

Avian metapneumovirus subtype C (aMPV/C) causes a severe upper respiratory tract (URT) infection in turkeys. Turkeys were inoculated oculonasally with inactivated aMPV/C adjuvanted with synthetic double-stranded RNA polyriboinosinic polyribocytidylic acid (Poly IC). Immunized turkeys had elevated numbers of mucosal IgA+ cells in the URT and increased levels of virus-specific IgG and IgA in the lachrymal fluid and IgG in the serum. After 7 or 21 days post immunization, turkeys were challenged oculonasally with pathogenic aMPV/C. Immunized groups were protected against respiratory lesions induced by the challenge virus. Further, the viral copy number of the challenge virus in the URT were significantly lower in the immunized turkeys than in the unimmunized turkeys (P<0.05). These results showed that inactivated aMPV/C administered by the respiratory route induced protective immunity against pathogenic virus challenge. Copyright © 2010 Elsevier Ltd. All rights reserved.

Inactivation of STAT3 Signaling Impairs Hair Cell Differentiation in the Developing Mouse Cochlea

Directory of Open Access Journals (Sweden)

Qianqian Chen

2017-07-01

Full Text Available Although STAT3 signaling is demonstrated to regulate sensory cell differentiation and regeneration in the zebrafish, its exact role is still unclear in mammalian cochleae. Here, we report that STAT3 and its activated form are specifically expressed in hair cells during mouse cochlear development. Importantly, conditional cochlear deletion of Stat3 leads to an inhibition on hair cell differentiation in mice in vivo and in vitro. By cell fate analysis, inactivation of STAT3 signaling shifts the cell division modes from asymmetric to symmetric divisions from supporting cells. Moreover, inhibition of Notch signaling stimulates STAT3 phosphorylation, and inactivation of STAT3 signaling attenuates production of supernumerary hair cells induced by a Notch pathway inhibitor. Our findings highlight an important role of the STAT3 signaling during mouse cochlear hair cell differentiation and may have clinical implications for the recovery of hair cell loss-induced hearing impairment.

Inactivation of enteropathogenic E. coli by solar disinfection (SODIS) under simulated sunlight conditions

CSIR Research Space (South Africa)

Ubomba-Jaswa, Eunice

2008-12-01

Full Text Available of limitations. An important limitation is the lack of SODIS inactivation studies on some waterborne pathogens in the developing world. SODIS inactivation of enteropathogenic E. coli (EPEC), a major cause of infantile diarrhoea is reported for the first time...

Heat inactivation kinetics of Hypocrea orientalis β-glucosidase with enhanced thermal stability by glucose.

Science.gov (United States)

Xu, Xin-Qi; Shi, Yan; Wu, Xiao-Bing; Zhan, Xi-Lan; Zhou, Han-Tao; Chen, Qing-Xi

2015-11-01

Thermal inactivation kinetics of Hypocrea orientalis β-glucosidase and effect of glucose on thermostability of the enzyme have been determined in this paper. Kinetic studies showed that the thermal inactivation was irreversible and first-order reaction. The microscopic rate constants for inactivation of free enzyme and substrate-enzyme complex were both determined, which suggested that substrates can protect β-glucosidase against thermal deactivation effectively. On the other hand, glucose was found to protect β-glucosidase from heat inactivation to remain almost whole activity below 70°C at 20mM concentration, whereas the apparent inactivation rate of BG decreased to be 0.3×10(-3)s(-1) in the presence of 5mM glucose, smaller than that of sugar-free enzyme (1.91×10(-3)s(-1)). The intrinsic fluorescence spectra results showed that glucose also had stabilizing effect on the conformation of BG against thermal denaturation. Docking simulation depicted the interaction mode between glucose and active residues of the enzyme to produce stabilizing effect. Copyright © 2015 Elsevier B.V. All rights reserved.

Elective Inactivation of Total Artificial Heart Technology in Non-Futile Situations: Inpatients, Outpatients and Research Participants

Science.gov (United States)

Bramstedt, Katrina A.

2004-01-01

Total artificial heart technology as a potential clinical therapy raises the issue of elective device inactivation in both futile and non-futile situations. This article explores elective device inactivation in non-futile situations. In reply to such requests for inactivation, the medical team should reflect on the individual's decision-making…

High-pressure processing of apple juice: kinetics of pectin methyl esterase inactivation.

Science.gov (United States)

Riahi, Esmaeil; Ramaswamy, Hosahalli S

2003-01-01

High-pressure (HP) inactivation kinetics of pectin methyl esterase (PME) in apple juice were evaluated. Commercial PME was dispensed in clarified apple juice, sealed in dual peel sterilizable plastic bags, and subjected to different high-pressure processing conditions (200-400 MPa, 0-180 min). Residual enzyme activity was determined by a titration method estimating the rate of free carboxyl group released by the enzyme acting on pectin substrate at pH 7.5 (30 degrees C). The effects of pressure level and pressure holding time on enzyme inactivation were significant (p < 0.05). PME from the microbial source was found to be more resistant (p < 0.05) to pressure inactivation than PME from the orange peel. Almost a full decimal reduction in the activity of commercial PME was achieved by HP treatment at 400 MPa for 25 min. Inactivation kinetics were evaluated on the basis of a dual effect model involving a pressure pulse effect and a first-order rate model, and the pressure sensitivity of rate constants was modeled by using the z-value concept.

Intrinsic Toxin-Derived Peptides Destabilize and Inactivate Clostridium difficile TcdB

Directory of Open Access Journals (Sweden)

Jason L. Larabee

2017-05-01

Full Text Available Clostridium difficile infection (CDI is a major cause of hospital-associated, antibiotic-induced diarrhea, which is largely mediated by the production of two large multidomain clostridial toxins, TcdA and TcdB. Both toxins coordinate the action of specific domains to bind receptors, enter cells, and deliver a catalytic fragment into the cytosol. This results in GTPase inactivation, actin disassembly, and cytotoxicity. TcdB in particular has been shown to encode a region covering amino acids 1753 to 1851 that affects epitope exposure and cytotoxicity. Surprisingly, studies here show that several peptides derived from this region, which share the consensus sequence 1769NVFKGNTISDK1779, protect cells from the action of TcdB. One peptide, PepB2, forms multiple interactions with the carboxy-terminal region of TcdB, destabilizes TcdB structure, and disrupts cell binding. We further show that these effects require PepB2 to form a higher-order polymeric complex, a process that requires the central GN amino acid pair. These data suggest that TcdB1769–1779 interacts with repeat sequences in the proximal carboxy-terminal domain of TcdB (i.e., the CROP domain to alter the conformation of TcdB. Furthermore, these studies provide insights into TcdB structure and functions that can be exploited to inactivate this critical virulence factor and ameliorate the course of CDI.

Microwave-Irradiation-Assisted HVAC Filtration for Inactivation of Viral Aerosols (Postprint)

Science.gov (United States)

2012-02-01

Baggiani, A. and Senesi, S. (2004). Effect of Microwave Radiation on Bacillus subtilis Spores . J. Appl. Microbiol. 97: 1220–1227. Damit, B., Lee, C.N...AFRL-RX-TY-TP-2012-0020 MICROWAVE-IRRADIATION-ASSISTED HVAC FILTRATION FOR INACTIVATION OF VIRAL AEROSOLS POSTPRINT Myung-Heui Woo and...12-APR-2011 -- 11-DEC-2011 Microwave Irradiation-Assisted HVAC Filtration for Inactivation of Viral Aerosols (POSTPRINT) FA8650-06-C-5913 0602102F

Mobile sequences in the pyruvate dehydrogenase complex, the E2 component, the catalytic domain and the 2-oxogluturate dehydrogenase complex of Azotobacter vinelandii, as detected by 600 MHz 1H-NMR spectroscopy

International Nuclear Information System (INIS)

Hanemaaijer, R.; Vervoort, J.; Westphal, A.H.; Kok, A. de.; Veeger, C.

1988-01-01

600 MHz 1 H-NMR spectroscopy demonstrates that the pyruvate dehydrogenase complex of Azotobacter vinelandii contains regions of the polypeptide chain with intramolecular mobility. This mobility is located in the E 2 component and can probably be ascribed to alanine-proline-rich regions that link the lipoyl sibdiomains to each other as well as to the E 1 and E 3 binding domain. In the catalytic domain of E 2 which is thought to form a compact, rigid core, also conformational flexibility is observed. It is conceivable that the N-terminal region of the catalytic domain, which contains many alanine residues, is responsible for the observed mobility. In the low-field region of the 1 H-NMR spectrum of E 2 specific resonances are found, which can be ascribed to mobile phenylalanine, histidine and/or tyrosine residues which are located in the E 1 and E 3 binding domain that links the lipoyl domain to the catalytic domain. In the 1 H-NMR spectrum of the intact complex, these resonances cannot be observed, indicating a decreased mobility of the E 1 and E 3 binding domain. (author). 24 refs.; 2 figs

Weed seed inactivation in soil mesocosms via biosolarization with mature compost and tomato processing waste amendments.

Science.gov (United States)

Achmon, Yigal; Fernández-Bayo, Jesús D; Hernandez, Katie; McCurry, Dlinka G; Harrold, Duff R; Su, Joey; Dahlquist-Willard, Ruth M; Stapleton, James J; VanderGheynst, Jean S; Simmons, Christopher W

2017-05-01

Biosolarization is a fumigation alternative that combines passive solar heating with amendment-driven soil microbial activity to temporarily create antagonistic soil conditions, such as elevated temperature and acidity, that can inactivate weed seeds and other pest propagules. The aim of this study was to use a mesocosm-based field trial to assess soil heating, pH, volatile fatty acid accumulation and weed seed inactivation during biosolarization. Biosolarization for 8 days using 2% mature green waste compost and 2 or 5% tomato processing residues in the soil resulted in accumulation of volatile fatty acids in the soil, particularly acetic acid, and >95% inactivation of Brassica nigra and Solanum nigrum seeds. Inactivation kinetics data showed that near complete weed seed inactivation in soil was achieved within the first 5 days of biosolarization. This was significantly greater than the inactivation achieved in control soils that were solar heated without amendment or were amended but not solar heated. The composition and concentration of organic matter amendments in soil significantly affected volatile fatty acid accumulation at various soil depths during biosolarization. Combining solar heating with organic matter amendment resulted in accelerated weed seed inactivation compared with either approach alone. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Female-biased expression of long non-coding RNAs in domains that escape X-inactivation in mouse

Directory of Open Access Journals (Sweden)

Lu Lu

2010-11-01

Full Text Available Abstract Background Sexual dimorphism in brain gene expression has been recognized in several animal species. However, the relevant regulatory mechanisms remain poorly understood. To investigate whether sex-biased gene expression in mammalian brain is globally regulated or locally regulated in diverse brain structures, and to study the genomic organisation of brain-expressed sex-biased genes, we performed a large scale gene expression analysis of distinct brain regions in adult male and female mice. Results This study revealed spatial specificity in sex-biased transcription in the mouse brain, and identified 173 sex-biased genes in the striatum; 19 in the neocortex; 12 in the hippocampus and 31 in the eye. Genes located on sex chromosomes were consistently over-represented in all brain regions. Analysis on a subset of genes with sex-bias in more than one tissue revealed Y-encoded male-biased transcripts and X-encoded female-biased transcripts known to escape X-inactivation. In addition, we identified novel coding and non-coding X-linked genes with female-biased expression in multiple tissues. Interestingly, the chromosomal positions of all of the female-biased non-coding genes are in close proximity to protein-coding genes that escape X-inactivation. This defines X-chromosome domains each of which contains a coding and a non-coding female-biased gene. Lack of repressive chromatin marks in non-coding transcribed loci supports the possibility that they escape X-inactivation. Moreover, RNA-DNA combined FISH experiments confirmed the biallelic expression of one such novel domain. Conclusion This study demonstrated that the amount of genes with sex-biased expression varies between individual brain regions in mouse. The sex-biased genes identified are localized on many chromosomes. At the same time, sexually dimorphic gene expression that is common to several parts of the brain is mostly restricted to the sex chromosomes. Moreover, the study uncovered

Caught in-between: System for in-flow inactivation of enzymes as an intermediary step in “plug-and-play” microfluidic platforms

DEFF Research Database (Denmark)

Fernandes, Ana C.; Petersen, Benjamin; Møller, Lars

2018-01-01

for rapidenzyme inactivation. The thermal inactivation platform developed is compared with a standard benchtop ThermoMixer in terms of inactivation efficiency for glucose oxidase and catalase. A higher activity loss was observed for enzyme inactivation under flow conditions (inactivation achieved at 120 s...

Inactivation of purified human recombinant monoamine oxidases A and B by rasagiline and its analogues.

Science.gov (United States)

Hubálek, Frantisek; Binda, Claudia; Li, Min; Herzig, Yaacov; Sterling, Jeffrey; Youdim, Moussa B H; Mattevi, Andrea; Edmondson, Dale E

2004-03-25

The inactivation of purified human recombinant monoamine oxidases (MAO) A and B by rasagiline [N-propargyl-1(R)-aminoindan] and four of its analogues [N-propargyl-1(S)-aminoindan (S-PAI), 6-hydroxy-N-propargyl-1(R)-aminoindan (R-HPAI), N-methyl-N-propargyl-1(R)-aminoindan (R-MPAI), and 6-(N-methyl-N-ethyl carbamoyloxy)-N-propargyl-1(R)-aminoindan (R-CPAI)] has been investigated. All compounds tested, with the exception of R-CPAI, form stoichiometric N(5) flavocyanine adducts with the FAD moiety of either enzyme. No H(2)O(2) is produced during either MAO A or MAO B inactivation, which demonstrates that covalent addition occurs in a single turnover. Rasagiline has the highest specificity for MAO B, as demonstrated by a 100-fold higher inhibition potency (k(inact)/K(i)) compared to MAO A, with the remaining compounds exhibiting lower isozyme specificities. MAO B and MAO A are more selective for the R-enantiomer (rasagiline) compared to the S-enantiomer (S-PAI) by 2500-fold and 17-fold, respectively. Differences in UV/vis and CD spectral data of the complexes of the studied compounds with both MAO A and MAO B are interpreted in light of crystallographic data of complexes of MAO B with rasagiline and its analogues (Binda, C.; et al. J. Med. Chem. 2004, 47, 1767-1774.

[Inactivation of PMS2 gene by promoter methylation in nasopharyngeal carcinoma].

Science.gov (United States)

Ni, H F; Jiang, B; Zhou, Z; Li, Y; Yuan, X Y; Cao, X L; Huang, G W

2016-11-23

Objective: To investigate the inactivation of PMS2 gene mediated by promoter methylation and its regulatory mechanism in nasopharyngeal carcinoma (NPC). Methods: Fifty-four NPC tissues, 16 normal nasopharyngeal epithelia (NNE), 5 NPC cell lines (CNE1, CNE2, TWO3, HNE1 and HONE1) and 1 normal nasopharyngeal epithelial cell line (NP69) were collected.Methylation-specific PCR (MSP) was used to detect the PMS2 promoter methylation, semi-quantitative reverse transcription PCR (qRT-PCR) was applied to determine its mRNA expression, and immunohistochemistry (IHC) was used to detect the protein expression of PMS2. The expressions of PMS2 mRNA in CNE1 and CNE2 cells before and after treated with methyltransferase inhibitor 5-aza-2-deoxycytidine were analyzed by qRT-PCR. The impact of methylation and demethylation on the mRNA expression of PMS2, and the association of mRNA and protein expression of PMS2 with clinicopathological features of nasopharyngeal cancer were analyzed. Results: Methylation of PMS2 gene was detected in all of the five NPC cell lines, but not in normal nasopharyngeal epithelial NP69 cells. The methylation rate of PMS2 gene in NPC tissues was 63% (34/54), significantly higher than that of the normal nasopharyngeal epithelia (0/16, P PMS2 mRNA and protein were significantly down-regulated in the 54 NPC tissues when compared with those in the 16 NNE tissues ( P PMS2 mRNA was restored in the CNE1 and CNE2 cells.However, the expressions of PMS2 mRNA and protein were not significantly correlated with patients' age, gender, TNM stage, histopathologic type or lymph node metastasis ( P >0.05 for all). Conclusions: Promoter methylation-mediated inactivation of PMS2 gene participates in carcinogenesis and development of NPC. PMS2 may be a candidate tumor suppressor in the treatment for patients with inactivation of PMS2 promoter methylation.

Pharmacology of the Nav1.1 domain IV voltage sensor reveals coupling between inactivation gating processes.

Science.gov (United States)

Osteen, Jeremiah D; Sampson, Kevin; Iyer, Vivek; Julius, David; Bosmans, Frank

2017-06-27

The Na v 1.1 voltage-gated sodium channel is a critical contributor to excitability in the brain, where pathological loss of function leads to such disorders as epilepsy, Alzheimer's disease, and autism. This voltage-gated sodium (Na v ) channel subtype also plays an important role in mechanical pain signaling by primary afferent somatosensory neurons. Therefore, pharmacologic modulation of Na v 1.1 represents a potential strategy for treating excitability disorders of the brain and periphery. Inactivation is a complex aspect of Na v channel gating and consists of fast and slow components, each of which may involve a contribution from one or more voltage-sensing domains. Here, we exploit the Hm1a spider toxin, a Na v 1.1-selective modulator, to better understand the relationship between these temporally distinct modes of inactivation and ask whether they can be distinguished pharmacologically. We show that Hm1a inhibits the gating movement of the domain IV voltage sensor (VSDIV), hindering both fast and slow inactivation and leading to an increase in Na v 1.1 availability during high-frequency stimulation. In contrast, ICA-121431, a small-molecule Na v 1.1 inhibitor, accelerates a subsequent VSDIV gating transition to accelerate entry into the slow inactivated state, resulting in use-dependent block. Further evidence for functional coupling between fast and slow inactivation is provided by a Na v 1.1 mutant in which fast inactivation removal has complex effects on slow inactivation. Taken together, our data substantiate the key role of VSDIV in Na v channel fast and slow inactivation and demonstrate that these gating processes are sequential and coupled through VSDIV. These findings provide insight into a pharmacophore on VSDIV through which modulation of inactivation gating can inhibit or facilitate Na v 1.1 function.

Pulsed electric field inactivation in a microreactor

NARCIS (Netherlands)

Fox, M.B.

2006-01-01

Pulsed electric fields (PEF) is a novel, non-thermal pasteurization method which uses short, high electric field pulses to inactivate microorganisms. The advantage of a pasteurization method like PEF compared to regular heat pasteurization is that the taste, flavour, texture and nutritional value

Gamma radiation inactivation of pathogens in sludge under larger-scale condition

Energy Technology Data Exchange (ETDEWEB)

Sermkiattipong, N; Pongpat, S

1996-12-01

The effect of gamma radiation on microorganisms in sludge from Huay Kwang Sewage Treatment Plant and Vajira Hospital showed that total bacterial counts were reduced to 2-3 log cycles and 1-2 log cycles at 5 kGy irradiation with and without aeration, respectively. Inactivation of coliform bacteria in sludge required irradiation with and without aeration at the dosages of 3-4.5 and 4-5 kGy, respectively. A dose of 2-3 kGy was sufficient to inactivate fecal coliform bacteria and E. coli. The doses used for inactivation these bacteria depend on the irradiation condition and solid content in sludge sample. Irradiation with aeration led to an increased microbial inactivation. According to our results, the frequency of occurrence of salmonella e contaminated in sludge from Huay Kwang Sewage Treatment Plant and Vajira Hospital was 50% and 75%, respectively. A dose of 2 kGy irradiation with or without aeration, salmonella e could not be detected in any sludge. Clostridium perfringens organisms were also detected in non-irradiated and irradiated sludge from both sources. Moreover, a dose of 5 kGy irradiation with or without aeration was not enough to eliminate C. perfringens. However, no shigella e were isolated from any treatment of sludge

Complicated biallelic inactivation of Pten in radiation-induced mouse thymic lymphomas

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, Yu [Department of Biology, Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522 (Japan); Experimental Radiobiology for Children' s Health Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Takabatake, Takashi; Kakinuma, Shizuko; Amasaki, Yoshiko; Nishimura, Mayumi; Imaoka, Tatsuhiko; Yamauchi, Kazumi; Shang, Yi [Experimental Radiobiology for Children' s Health Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Miyoshi-Imamura, Tomoko [Experimental Radiobiology for Children' s Health Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Genetic Counseling Program, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyou-ku, Tokyo 112-8610 (Japan); Nogawa, Hiroyuki [Department of Biology, Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522 (Japan); Kobayashi, Yoshiro [Department of Biomolecular Science, Faculty of Science, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510 (Japan); Shimada, Yoshiya, E-mail: y_shimad@nirsgo.jp [Experimental Radiobiology for Children' s Health Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan)

2010-04-01

Inactivation of the phosphatase and tensin homolog gene (Pten) occurs via multiple tissue-dependent mechanisms including epigenetic silencing, point mutations, insertions, and deletions. Although frequent loss of heterozygosity around the Pten locus and plausible involvement of epigenetic silencing have been reported in radiation-induced thymic lymphomas, the proportion of lymphomas with inactivated Pten and the spectrum of causal aberrations have not been extensively characterized. Here, we assessed the mode of Pten inactivation by comprehensive analysis of the expression and alteration of Pten in 23 radiation-induced thymic lymphomas developed in B6C3F1 mice. We found no evidence for methylation-associated silencing of Pten; rather, complex structural abnormalities comprised of missense and nonsense mutations, 1- and 3-bp insertions, and focal deletions were identified in 8 of 23 lymphomas (35%). Sequencing of deletion breakpoints suggested that aberrant V(D)J recombination and microhomology-mediated rearrangement were responsible for the focal deletions. Seven of the 8 lymphomas had biallelic alterations, and 4 of them did not express Pten protein. These Pten aberrations coincided with downstream Akt phosphorylation. In conclusion, we demonstrate that Pten inactivation is frequently biallelic and is caused by a variety of structural abnormalities (rather than by epigenetic silencing) and is involved in radiation-induced lymphomagenesis.

Gamma radiation inactivation of pathogens in sludge under larger-scale condition

International Nuclear Information System (INIS)

Sermkiattipong, N.; Pongpat, S.

1996-01-01

The effect of gamma radiation on microorganisms in sludge from Huay Kwang Sewage Treatment Plant and Vajira Hospital showed that total bacterial counts were reduced to 2-3 log cycles and 1-2 log cycles at 5 kGy irradiation with and without aeration, respectively. Inactivation of coliform bacteria in sludge required irradiation with and without aeration at the dosages of 3-4.5 and 4-5 kGy, respectively. A dose of 2-3 kGy was sufficient to inactivate fecal coliform bacteria and E. coli. The doses used for inactivation these bacteria depend on the irradiation condition and solid content in sludge sample. Irradiation with aeration led to an increased microbial inactivation. According to our results, the frequency of occurrence of salmonella e contaminated in sludge from Huay Kwang Sewage Treatment Plant and Vajira Hospital was 50% and 75%, respectively. A dose of 2 kGy irradiation with or without aeration, salmonella e could not be detected in any sludge. Clostridium perfringens organisms were also detected in non-irradiated and irradiated sludge from both sources. Moreover, a dose of 5 kGy irradiation with or without aeration was not enough to eliminate C. perfringens. However, no shigella e were isolated from any treatment of sludge

A Chimeric LysK-Lysostaphin Fusion Enzyme Lysing Staphylococcus aureus Cells: a Study of Both Kinetics of Inactivation and Specifics of Interaction with Anionic Polymers.

Science.gov (United States)

Filatova, Lyubov Y; Donovan, David M; Ishnazarova, Nadiya T; Foster-Frey, Juli A; Becker, Stephen C; Pugachev, Vladimir G; Balabushevich, Nadezda G; Dmitrieva, Natalia F; Klyachko, Natalia L

2016-10-01

A staphylolytic fusion protein (chimeric enzyme K-L) was created, harboring three unique lytic activities composed of the LysK CHAP endopeptidase, and amidase domains, and the lysostaphin glycyl-glycine endopeptidase domain. To assess the potential of possible therapeutic applications, the kinetic behavior of chimeric enzyme K-L was investigated. As a protein antimicrobial, with potential antigenic properties, the biophysical effect of including chimeric enzyme K-L in anionic polymer matrices that might help reduce the immunogenicity of the enzyme was tested. Chimeric enzyme K-L reveals a high lytic activity under the following optimal ( opt ) conditions: pH opt 6.0-10.0, t opt 20-30 °C, NaCl opt 400-800 mM. At the working temperature of 37 °C, chimeric enzyme K-L is inactivated by a monomolecular mechanism and possesses a high half-inactivation time of 12.7 ± 3.0 h. At storage temperatures of 22 and 4 °C, a complex mechanism (combination of monomolecular and bimolecular mechanisms) is involved in the chimeric enzyme K-L inactivation. The optimal storage conditions under which the enzyme retains 100 % activity after 140 days of incubation (4 °C, the enzyme concentration of 0.8 mg/mL, pH 6.0 or 7.5) were established. Chimeric enzyme K-L is included in complexes with block-copolymers of poly-L-glutamic acid and polyethylene glycol, while the enzyme activity and stability are retained, thus suggesting methods to improve the application of this fusion as an effective antimicrobial agent.

Pharmacological inactivation does not support a unique causal role for intraparietal sulcus in the discrimination of visual number.

Directory of Open Access Journals (Sweden)

Nicholas K DeWind

Full Text Available The "number sense" describes the intuitive ability to quantify without counting. Single neuron recordings in non-human primates and functional imaging in humans suggest the intraparietal sulcus is an important neuroanatomical locus of numerical estimation. Other lines of inquiry implicate the IPS in numerous other functions, including attention and decision making. Here we provide a direct test of whether IPS has functional specificity for numerosity judgments. We used muscimol to reversibly and independently inactivate the ventral and lateral intraparietal areas in two monkeys performing a numerical discrimination task and a color discrimination task, roughly equilibrated for difficulty. Inactivation of either area caused parallel impairments in both tasks and no evidence of a selective deficit in numerical processing. These findings do not support a causal role for the IPS in numerical discrimination, except insofar as it also has a role in the discrimination of color. We discuss our findings in light of several alternative hypotheses of IPS function, including a role in orienting responses, a general cognitive role in attention and decision making processes and a more specific role in ordinal comparison that encompasses both number and color judgments.

Functional size analysis of bioactive materials by radiation inactivation

International Nuclear Information System (INIS)

Kume, Tamikazu

1994-01-01

When the research on various proteins including enzymes is carried out, first molecular weight is measured. The physical chemical methods used for measuring molecular weight cannot measure it in the state of actually acting in living bodies. Radiation inactivation method is the unique method which can measure the molecular weight of the active substances in living bodies. Paying attention to this point, recently it is attempted to measure the activity unit of enzymes, receptors and others, and to apply to the elucidation of their functions. In this report, the concept of the method of measuring molecular size based on radiation inactivation, the detailed experimental method and the points to which attention must be paid are described. Also its application to the elucidation of living body functions according to the example of the studies by the author is reported. The concept of the measurement of molecular weight by radiation inactivation is based on target theory. The preparation of samples, the effect of oxygen, radiation sources, dosimetry, irradiation temperature, internal standard process and so on are reported. The trend of the research is shown. (K.I.)

Viral inactivation in hemotherapy: systematic review on inactivators with action on nucleic acids

Directory of Open Access Journals (Sweden)

Patricia Marial Sobral

2012-01-01

Full Text Available The aim of this study was to conduct a systematic review on the photoinactivators used in hemotherapy, with action on viral genomes. The SciELO, Science Direct, PubMed and Lilacs databases were searched for articles. The inclusion criterion was that these should be articles on inactivators with action on genetic material that had been published between 2000 and 2010. The key words used in identifying such articles were "hemovigilance", "viral inactivation", "photodynamics", "chemoprevention" and "transfusion safety". Twenty-four articles on viral photoinactivation were found with the main photoinactivators covered being: methylene blue, amotosalen HCl, S-303 frangible anchor linker effector (FRALE, riboflavin and inactin. The results showed that methylene blue has currently been studied least, because it diminishes coagulation factors and fibrinogen. Riboflavin has been studied most because it is a photoinactivator of endogenous origin and has few collateral effects. Amotosalen HCl is effective for platelets and is also used on plasma, but may cause changes both to plasma and to platelets, although these are not significant for hemostasis. S-303 FRALE may lead to neoantigens in erythrocytes and is less indicated for red-cell treatment; in such cases, PEN 110 is recommended. Thus, none of the methods for pathogen reduction is effective for all classes of agents and for all blood components, but despite the high cost, these photoinactivators may diminish the risk of blood-transmitted diseases.

Deletion of an X-inactivation boundary disrupts adjacent gene silencing.

Directory of Open Access Journals (Sweden)

Lindsay M Horvath

2013-11-01

Full Text Available In mammalian females, genes on one X are largely silenced by X-chromosome inactivation (XCI, although some "escape" XCI and are expressed from both Xs. Escapees can closely juxtapose X-inactivated genes and provide a tractable model for assessing boundary function at epigenetically regulated loci. To delimit sequences at an XCI boundary, we examined female mouse embryonic stem cells carrying X-linked BAC transgenes derived from an endogenous escape locus. Previously we determined that large BACs carrying escapee Kdm5c and flanking X-inactivated transcripts are properly regulated. Here we identify two lines with truncated BACs that partially and completely delete the distal Kdm5c XCI boundary. This boundary is not required for escape, since despite integrating into regions that are normally X inactivated, transgenic Kdm5c escapes XCI, as determined by RNA FISH and by structurally adopting an active conformation that facilitates long-range preferential association with other escapees. Yet, XCI regulation is disrupted in the transgene fully lacking the distal boundary; integration site genes up to 350 kb downstream of the transgene now inappropriately escape XCI. Altogether, these results reveal two genetically separable XCI regulatory activities at Kdm5c. XCI escape is driven by a dominant element(s retained in the shortest transgene that therefore lies within or upstream of the Kdm5c locus. Additionally, the distal XCI boundary normally plays an essential role in preventing nearby genes from escaping XCI.

Enteric virus removal inactivation by coal-based media

Energy Technology Data Exchange (ETDEWEB)

Gupta, A.; Chaudhuri, M. [Indian Institute of Technology, Kanpur (India). Dept. of Civil Engineering

1995-02-01

Four coal-based media, viz. alum-pretreated or ferric hydroxide-impregnated Giridih bituminous coal and lignite (alum-GBC, Fe-GBC; alum-lignite and Fe-Lignite) were laboratory tested to assess their potential in removing/inactivating enteric viruses in water. Batch-sorption screening tests, employing a poliovirus-spiked canal water, indicated high poliovirus sorption by Fe-GBC and alum-GBC in a short contact time of 5 min. Based on the results of further batch-sorption tests, using silver incorporated media (alum/Ag-GBC, alum-GBC-Ag and Fe-GBC-Ag), as well as aesthetic water quality consideration and previous findings on removal of coliforms and turbidity, alum/Ag-GBC, alum-GBC and alum-GBC-AG were included in downflow column studies employing poliovirus-spiked canal water. All three media showed potential in removing/inactivating enteric viruses. In a separate column study employing a joint challenge of poliovirus and rotavirus, alum/Ag-GBC removed 59.3-86.5% of the viruses along with more than 99% reduction in indigenous heterotrophic bacteria. Alum/silver-pretreated bituminous coal medium appears promising for use in household water filters in rural areas of the developing world. However, improved medium preparation to further enhance its efficiency is needed; also, its efficacy in removing/inactivating indigenous enteric bacteria, viruses and protozoa has to be ensured and practicalities or economics of application need to be considered.

High Pressure Inactivation of HAV within Mussels

Science.gov (United States)

The potential of hepatitis A virus (HAV) to be inactivated within Mediterranean mussels (Mytilus galloprovincialis) and blue mussels (Mytilus edulis) by high pressure processing was evaluated. HAV was bioaccumulated within mussels to approximately 6-log10 PFU by exposure of mussels to HAV-contamina...

CHLORINE INACTIVATION OF CATEGORY "A" BIO-TERRORISM AGENTS

Science.gov (United States)

This poster presents information on the inactivation of select bioterrorist agents. Information will be presented on chlorine disinfection of vegetative cells of Brucella suis, Brucella melitensis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis and endos...

Focus formation and neoplastic transformation by herpes simplex virus type 2 inactivated intracellularly by 5-bromo-2'-deoxyuridine and near UV light

International Nuclear Information System (INIS)

Manak, M.M.; Aurelian, L.; Ts'o, P.O.

1981-01-01

The induction of focus formation in low serum and of neoplastic transformation of Syrian hamster embryo cells was examined after the expression of herpes simplex virus type 2 functions. Syrian hamster embryo cells infected at a high multiplicity (5 PFU/cell) with 5-bromo-2'-deoxyuridine-labeled herpes simplex virus type 2 (11% substitution of thymidine residues) were exposed to near UV light irradiation at various times postinfection. This procedure specifically inactivated the viral genome, while having little, if any, effect on the unlabeled cellular DNA. Focus formation in 1% serum and neoplastic transformation were observed in cells exposed to virus inactivated before infection, but the frequency was enhanced (15- to 27-fold) in cells in which the virus was inactivated at 4 to 8 h postinfection. Only 2 to 45 independently isolated foci were capable of establishing tumorigenic lines. The established lines exhibited phenotypic alterations characteristic of a transformed state, including reduced serum requirement, anchorage-independent growth, and tumorigenicity. They retained viral DNA sequences and, even at relatively late passage, expressed viral antigens, including ICP 10

Promoter hypermethylation of KLF4 inactivates its tumor suppressor function in cervical carcinogenesis.

Directory of Open Access Journals (Sweden)

Wen-Ting Yang

Full Text Available OBJECTIVE: The KLF4 gene has been shown to be inactivated in cervical carcinogenesis as a tumor suppressor. However, the mechanism of KLF4 silencing in cervical carcinomas has not yet been identified. DNA methylation plays a key role in stable suppression of gene expression. METHODS: The methylation status of the KLF4 promoter CpG islands was analyzed by bisulfite sequencing (BSQ in tissues of normal cervix and cervical cancer. KLF4 gene expression was detected by RT-PCR, immunohistochemistry and western blot. KLF4 promoter methylation in cervical cancer cell line was determined by BSQ and methylation-specific polymerase chain reaction (MS-PCR. Cell proliferation ability was detected by cell growth curve and MTT assay. RESULTS: The methylated allele was found in 41.90% of 24 cervical cancer tissues but only in 11.11% of 11 normal cervix tissues (P<0.005. KLF4 mRNA levels were significantly reduced in cervical cancer tissues compared with normal cervix tissues (P<0.01 and KLF4 mRNA expression showed a significant negative correlation with the promoter hypermethylation (r = -0.486, P = 0.003. Cervical cancer cell lines also showed a significant negative correlation between KLF4 expression and hypermethylation. After treatment with the demethylating agent 5-Azacytidine (5-Aza, the expression of KLF4 in the cervical cancer cell lines at both mRNA and protein levels was drastically increased, the cell proliferation ability was inhibited and the chemosensitivity for cisplatin was significantly increased. CONCLUSION: KLF4 gene is inactivated by methylation-induced silencing mechanisms in a large subset of cervical carcinomas and KLF4 promoter hypermethylation inactivates the gene's function as a tumor suppressor in cervical carcinogenesis.

Roles of singlet oxygen and triplet excited state of dissolved organic matter formed by different organic matters in bacteriophage MS2 inactivation

KAUST Repository

Rosado-Lausell, Sahid L.; Wang, Hanting; Gutié rrez, Leonardo A.; Romero-Maraccini, Ofelia C.; Niu, Xi-Zhi; Gin, Karina; Croue, Jean-Philippe; Nguyen, Thanh Ha

2013-01-01

Inactivation of bacteriophage MS2 by reactive oxygen species (ROS) and triplet excited state of dissolved organic matter (3DOM*) produced by irradiation of natural and synthetic sensitizers with simulated sunlight of wavelengths greater than 320nm was investigated. Natural sensitizers included purified DOM isolates obtained from wastewater and river waters, and water samples collected from Singapore River, Stamford Canal, and Marina Bay Reservoir in Singapore. Linear correlations were found between MS2 inactivation rate constants (kobs) and the photo-induced reaction rate constants of 2,4,6-trimethylphenol (TMP), a probe compound shown to react mainly with 3DOM*. Linear correlations between MS2 kobs and singlet oxygen (1O2) concentrations were also found for both purified DOM isolates and natural water samples. These correlations, along with data from quenching experiments and experiments with synthetic sensitizers, Rose Bengal (RB), 3'-methoxyacetophenone (3'-MAP), and nitrite (NO2-), suggest that 1O2, 3DOM*, and hydroxyl radicals (•OH) could inactivate bacteriophage MS2. Linear correlations between MS2 kobs and Specific Ultraviolet Absorption determined at 254nm (SUVA254) were also found for both purified DOM isolates and natural samples. These results suggest the potential use of TMP as a chemical probe and SUVA254 as an indicator for virus inactivation in natural and purified DOM water samples. © 2013 Elsevier Ltd.

Roles of singlet oxygen and triplet excited state of dissolved organic matter formed by different organic matters in bacteriophage MS2 inactivation

KAUST Repository

Rosado-Lausell, Sahid L.

2013-09-01

Inactivation of bacteriophage MS2 by reactive oxygen species (ROS) and triplet excited state of dissolved organic matter (3DOM*) produced by irradiation of natural and synthetic sensitizers with simulated sunlight of wavelengths greater than 320nm was investigated. Natural sensitizers included purified DOM isolates obtained from wastewater and river waters, and water samples collected from Singapore River, Stamford Canal, and Marina Bay Reservoir in Singapore. Linear correlations were found between MS2 inactivation rate constants (kobs) and the photo-induced reaction rate constants of 2,4,6-trimethylphenol (TMP), a probe compound shown to react mainly with 3DOM*. Linear correlations between MS2 kobs and singlet oxygen (1O2) concentrations were also found for both purified DOM isolates and natural water samples. These correlations, along with data from quenching experiments and experiments with synthetic sensitizers, Rose Bengal (RB), 3\\'-methoxyacetophenone (3\\'-MAP), and nitrite (NO2-), suggest that 1O2, 3DOM*, and hydroxyl radicals (•OH) could inactivate bacteriophage MS2. Linear correlations between MS2 kobs and Specific Ultraviolet Absorption determined at 254nm (SUVA254) were also found for both purified DOM isolates and natural samples. These results suggest the potential use of TMP as a chemical probe and SUVA254 as an indicator for virus inactivation in natural and purified DOM water samples. © 2013 Elsevier Ltd.

Reactive radical-driven bacterial inactivation by hydrogen-peroxide-enhanced plasma-activated-water

Science.gov (United States)

Wu, Songjie; Zhang, Qian; Ma, Ruonan; Yu, Shuang; Wang, Kaile; Zhang, Jue; Fang, Jing

2017-08-01

The combined effects of plasma activated water (PAW) and hydrogen peroxide (H2O2), PAW/HP, in sterilization were investigated in this study. To assess the synergistic effects of PAW/HP, S. aureus was selected as the test microorganism to determine the inactivation efficacy. Also, the DNA/RNA and proteins released by the bacterial suspensions under different conditions were examined to confirm membrane integrity. Additionally, the intracellular pH (pHi) of S. aureus was measured in our study. Electron spin resonance spectroscopy (ESR) was employed to identify the presence of radicals. Finally, the oxidation reduction potential (ORP), conductivity and pH were measured. Our results revealed that the inactivation efficacy of PAW/HP is much greater than that of PAW, while increased H2O2 concentration result in higher inactivation potential. More importantly, as compared with PAW, the much stronger intensity ESR signals and higher ORP in PAW/HP suggests that the inactivation mechanism of the synergistic effects of PAW/HP: more reactive oxygen species (ROS) and reactive nitrogen species (RNS), especially OH and NO radicals, are generated in PAW combined with H2O2 resulting in more deaths of the bacteria.

N-type Cu2O Film for Photocatalytic and Photoelectrocatalytic Processes: Its stability and Inactivation of E. coli

International Nuclear Information System (INIS)

Xiong, Liangbin; Ng, Tsz Wai; Yu, Ying; Xia, Dehua; Yip, Ho Yin; Li, Guiying; An, Taicheng; Zhao, Huijun; Wong, Po Keung

2015-01-01

Highlights: • Photoelectrocatalytic inactivation of E. coli by Cu 2 O film was firstly reported. • 7 log of E. coli could be completely inactivated in 2 h by Cu 2 O with a 0.1 V bias. • Charge transfer between Cu 2 O and E. coli was monitored by electrochemical technique. • Inactivation of E. coli by electric charges of electrodes was in-depth investigated. • Stability of N-type Cu 2 O as a photocatalyst was studied for the first time. - ABSTRACT: Photoelectrocatalytic (PEC) inactivation of Escherichia coli K-12 by cuprous oxide (Cu 2 O) film irradiated by visible light is firstly reported. A complete inactivation of about 7 log of E. coli was obtained for Cu 2 O film within 6 h. The bacterial inactivation efficiency was significantly improved in a photoelectrochemical cell, in which 7 log of E. coli could be completely inactivated within 2 h by Cu 2 O film with a 0.1 V bias. Electric charge transfer between electrodes and E. coli, and electric charge inactivation towards E. coli were investigated using membrane-separated reactor combined with short circuit photocurrent technique. H 2 O 2 , hole, and toxicity of Cu 2 O film were found responsible for the inactivation of E. coli. Toxicity of copper ions (including Cu 2+ and Cu + ) leakage from Cu 2 O films was determined and the results showed that the amount of leakage copper ions was not toxic to E. coli. Finally, the Cu 2 O film was proved to be effective and reusable for PC and PEC inactivation of E. coli

Function of the activated protein C (APC) autolysis loop in activated FVIII inactivation.

Science.gov (United States)

Cramer, Thomas J; Gale, Andrew J

2011-06-01

Activated protein C (APC) binds to its substrates activated factor V (FVa) and activated factor VIII (FVIIIa) with a basic exosite that consists of loops 37, 60, 70 and the autolysis loop. These loops have a high density of basic residues, resulting in a positive charge on the surface of APC. Many of these residues are important in the interaction of APC with FVa and FVIIIa. The current study focused on the function of the autolysis loop in the interaction with FVIIIa. This loop was previously shown to interact with FVa, and it inhibits APC inactivation by plasma serpins. Charged residues of the autolysis loop were individually mutated to alanine and the activity of these mutants was assessed in functional FVIIIa inactivation assays. The autolysis loop was functionally important for FVIIIa inactivation. Mutation of R306, K311 and R314 each resulted in significantly reduced FVIIIa inactivation. The inactivating cleavages of FVIIIa at R336 and R562 were affected equally by the mutations. Protein S and FV stimulated cleavage at R562 more than cleavage at R336, independent of mutations in the autolysis loop. Together, these results confirmed that the autolysis loop plays a significant role as part of the basic exosite on APC in the interaction with FVIIIa. © 2011 Blackwell Publishing Ltd.

Use of laser-UV for inactivation of virus in blood products

International Nuclear Information System (INIS)

Prodouz, K.N.; Fratantoni, J.C.; Boone, E.J.; Bonner, R.F.

1987-01-01

Inactivation of virus by UV radiation was examined as a potential method for sterilization of blood products. Samples of attenuated poliovirus, platelets and plasma were uniformly irradiated with a XeCl excimer laser that delivered 40 nsec pulses of UV at 308 nm (UVB308). Intensities and exposure does were varied from 0.11 to 1.40 MW/cm2 and 0.51 to 56.0 J/cm2, respectively. In studies conducted with low intensity UVB308 (less than or equal to 0.17 MW/cm2), using exposure doses greater than or equal to 10.8 J/cm2, it was possible to inactivate poliovirus by 4 to 6 log10. Platelets irradiated with doses less than or equal to 21.5 J/cm2 exhibited minimal damage as assessed by aggregation activity and spontaneous release of serotonin. Examination of the coagulation activity of irradiated plasma indicated that exposure doses less than or equal to 21.5 J/cm2 resulted in less than 20% increase in prothrombin and partial thromboplastin times. The use of UVB308 at a higher intensity (1.4 MW/cm2) over a similar range of exposure doses did not enhance viral inactivation but did result in increased damage to platelet and plasma proteins. These results demonstrate that at 308 nm there exists a window of efficacy for exposure doses between 10.8 and 21.5 J/cm2 and peak intensities less than or equal to 0.17 MW/cm2 in which a hardy virus is significantly inactivated and platelets and plasma proteins are, by functional criteria, minimally affected. Increased viral inactivation cannot be accomplished with higher UV intensities and will require additional or alternate measures

Effects of inactivation of the anterior interpositus nucleus on the kinematic and dynamic control of multijoint movement.

Science.gov (United States)

Cooper, S E; Martin, J H; Ghez, C

2000-10-01

We previously showed that inactivating the anterior interpositus nucleus in cats disrupts prehension; paw paths, normally straight and accurate, become curved, hypometric, and more variable. In the present study, we determined the joint kinematic and dynamic origins of this impairment. Animals were restrained in a hammock and trained to reach and grasp a cube of meat from a narrow food well at varied heights; movements were monitored using the MacReflex analysis system. The anterior interpositus nucleus was inactivated by microinjection of the GABA agonist muscimol (0.25-0.5 microgram in 0.5 microliter saline). For each joint, we computed the torque due to gravity, inertial resistance (termed self torque), interjoint interactions (termed interaction torque), and the combined effects of active muscle contraction and passive soft tissue stretch (termed generalized muscle torque). Inactivation produced significant reductions in the amplitude, velocity, and acceleration of elbow flexion. However, these movements continued to scale normally with target height. Shoulder extension was reduced by inactivation but wrist angular displacement and velocity were not. Inactivation also produced changes in the temporal coordination between elbow, shoulder, and wrist kinematics. Dynamic analysis showed that elbow flexion both before and during inactivation was produced by the combined action of muscle and interaction torque, but that the timing depended on muscle torque. Elbow interaction and muscle torques were scaled to target height both before and during inactivation. Inactivation produced significant reductions in elbow flexor interaction and muscle torques. The duration of elbow flexor muscle torque was prolonged to compensate for the reduction in flexor interaction torque. Shoulder extension was produced by extensor interaction and muscle torques both before and during inactivation. Inactivation produced a reduction in shoulder extension, primarily by reduced interaction

Novel recombinant adeno-associated viruses for Cre activated and inactivated transgene expression in neurons

Science.gov (United States)

Saunders, Arpiar; Johnson, Caroline A.; Sabatini, Bernardo L.

2012-01-01

Understanding the organization of the nervous system requires methods for dissecting the contributions of each component cell type to circuit function. One widely used approach combines genetic targeting of Cre recombinase to specific cell populations with infection of recombinant adeno-associated viruses (rAAVs) whose transgene expression is activated by Cre (“Cre-On”). Distinguishing how the Cre-expressing neurons differ functionally from neighboring Cre-negative neurons requires rAAVs that are inactivated by Cre (“Cre-Off”) and can be used in tandem with Cre-On viruses. Here we introduce two rAAV vectors that are inactivated by Cre and carry different fluorophore and optogenetic constructs. We demonstrate single and dual rAAV systems to achieve Cre-On and Cre-Off expression in spatially-intermingled cell populations of the striatum. Using these systems, we uncovered cryptic genomic interactions that occur between multiple Cre-sensitive rAAVs or between Cre-sensitive rAAVs and somatic Cre-conditional alleles and devised methods to avoid these interactions. Our data highlight both important experimental caveats associated with Cre-dependent rAAV use as well as opportunities for the development of improved rAAVs for gene delivery. PMID:22866029

Mechanistic study of the visible-light-driven photocatalytic inactivation of bacteria by graphene oxide–zinc oxide composite

International Nuclear Information System (INIS)

Wu, Dan; An, Taicheng; Li, Guiying; Wang, Wei; Cai, Yuncheng; Yip, Ho Yin; Zhao, Huijun; Wong, Po Keung

2015-01-01

Graphical abstract: - Highlights: • The GO–ZnO composites exhibited efficient VLD bacterial inactivation performance. • Strong interfacial interaction existed between GO and ZnO. • GO served as a photosensitizer in the inactivation process. • Excellent antibacterial activity by GO–ZnO composite was shown under sunlight. • An inactivation mechanism based on the GO photosensitizer induction was proposed. - Abstract: The visible-light-driven (VLD) photocatalytic activity of graphene oxide–zinc oxide (GO–ZnO) composite prepared by a simple hydrothermal method was evaluated toward the inactivation of Escherichia coli K-12. The results showed that GO–ZnO composite had excellent VLD photocatalytic bacterial inactivation activity, comparing with those of ZnO and GO, which was attributed to the strong interaction between ZnO and GO in the composite. Accordingly, an interaction induced VLD photocatalytic inactivation mechanism of the strong interaction of GO with ZnO within the GO–ZnO composite was proposed. GO served as a photosensitizer and facilitated the charge separation and transfer, thus boosted the massive production of reactive oxygen species such as ·OH bulk , which was identified as the major reactive species from conduction band of ZnO, and resulted in a remarkable enhancement of bacterial inactivation efficiency. Moreover, GO–ZnO composite showed obviously superior photocatalytic bacterial inactivation within 10 min under natural solar light irradiation, indicating that GO–ZnO composite has great potential in wastewater treatment and environmental protection.

Instrument for Study of Microbial Thermal Inactivation

Science.gov (United States)

Dickerson, R. W.; Read, R. B.

1968-01-01

An instrument was designed for the study of thermal inactivation of microorganisms using heating times of less than 1 sec. The instrument operates on the principle of rapid automatic displacement of the microorganism to and from a saturated steam atmosphere, and the operating temperature range is 50 to 90 C. At a temperature of 70 C, thermometric lag (time required to respond to 63.2% of a step change) of the fluid sample containing microorganisms was 0.12 sec. Heating time required to heat the sample to within 0.1 C of the exposure temperature was less than 1 sec, permitting exposure periods as brief as 1 sec, provided the proper corrections are made for the lethal effect of heating. The instrument is most useful for heat exposure periods of less than 5 min, and, typically, more than 500 samples can be processed for microbial inactivation determinations within an 8-hr period. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 7 Fig. 8 PMID:4874466

The SKINT1-like gene is inactivated in hominoids but not in all primate species: implications for the origin of dendritic epidermal T cells.

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Rania Hassan Mohamed

Full Text Available Dendritic epidermal T cells, which express an invariant Vγ5Vδ1 T-cell receptor and account for 95% of all resident T cells in the mouse epidermis, play a critical role in skin immune surveillance. These γδ T cells are generated by positive selection in the fetal thymus, after which they migrate to the skin. The development of dendritic epidermal T cells is critically dependent on the Skint1 gene expressed specifically in keratinocytes and thymic epithelial cells, suggesting an indispensable role for Skint1 in the selection machinery for specific intraepithelial lymphocytes. Phylogenetically, rodents have functional SKINT1 molecules, but humans and chimpanzees have a SKINT1-like (SKINT1L gene with multiple inactivating mutations. In the present study, we analyzed SKINT1L sequences in representative primate species and found that all hominoid species have a common inactivating mutation, but that Old World monkeys such as olive baboons, green monkeys, cynomolgus macaques and rhesus macaques have apparently functional SKINT1L sequences, indicating that SKINT1L was inactivated in a common ancestor of hominoids. Interestingly, the epidermis of cynomolgus macaques contained a population of dendritic-shaped γδ T cells expressing a semi-invariant Vγ10/Vδ1 T-cell receptor. However, this population of macaque T cells differed from rodent dendritic epidermal T cells in that their Vγ10/Vδ1 T-cell receptors displayed junctional diversity and expression of Vγ10 was not epidermis-specific. Therefore, macaques do not appear to have rodent-type dendritic epidermal T cells despite having apparently functional SKINT1L. Comprehensive bioinformatics analysis indicates that SKINT1L emerged in an ancestor of placental mammals but was inactivated or lost multiple times in mammalian evolution and that Skint1 arose by gene duplication in a rodent lineage, suggesting that authentic dendritic epidermal T cells are presumably unique to rodents.

Inactivation of B. Pumilus spores by combination hydrostatic pressure-radiation treatment of parenteral solutions

International Nuclear Information System (INIS)

Wills, P.A.

1975-01-01

Bacterial spores are inactivated by moderate hydrostatic pressures. The radiation dose required to sterilize radiation sensitive pharmaceuticals can be considerably reduced using a combination hydrostatic pressure-radiation treatment. This paper describes a combination pressure-radiation sterilization process using Bacillus pumilus spores suspended in water, 0.9% saline, and 5% dextrose solutions. The optimum temperatures for spore inactivation at 35 MPa and the degree of inactivation at 35, 70 and 105 MPa applied for times up to 100 min have been determined. Inactivation was greatest in saline and least in dextrose. Spores in dextrose were only slightly less radiation resistant than in saline or water. It was calculated that the radiation dose required for sterilization could be halved with appropriate compression treatment. Examples of combinations of pressure-radiation suitable for sterilization are given. One combination is compression at 105 MPa for 18 min for a dose of 1.25 Mrad. (author)

Review: Efficiency of physical and chemical treatments on the inactivation of dairy bacteriophages

Directory of Open Access Journals (Sweden)

Daniela Marta Guglielmotti

2012-01-01

Full Text Available Bacteriophages can cause great economic losses due to fermentation failure in dairy plants. Hence, physical and chemical treatments of raw material and/or equipment are mandatory to maintain phage levels as low as possible. Regarding thermal treatments used to kill pathogenic bacteria or achieve longer shelf-life of dairy products, neither low temperature long time (LTLT nor high temperature short time (HTST pasteurization were able to inactivate most lactic acid bacteria (LAB phages. Even though most phages did not survive 90ºC for 2 min, there were some that resisted 90ºC for more than 15 min (conditions suggested by the International Dairy Federation, IDF, for complete phage destruction. Among biocides tested, ethanol showed variable effectiveness in phage inactivation, since only phages infecting dairy cocci and Lactobacillus helveticus were reasonably inactivated by this alcohol, whereas isopropanol was in all cases highly ineffective. In turn, peracetic acid has consistently proved to be very fast and efficient to inactivate dairy phages, whereas efficiency of sodium hypochlorite was variable, even among different phages infecting the same LAB species. Both alkaline chloride foam and ethoxylated nonylphenol with phosphoric acid were remarkably efficient, trait probably related to their highly alkaline or acidic pH values in solution, respectively. Photocatalysis using UV light and TiO2 has been recently reported as a feasible option to industrially inactivate phages infecting diverse LAB species. Processes involving high pressure were barely used for phage inactivation, but until now most studied phages revealed high resistance to these treatments. To conclude, and given the great phage diversity found on dairies, it is always advisable to combine different anti-phage treatments (biocides, heat, high pressure, photocatalysis, rather than using them separately at extreme conditions.

Inactivation of Microorganisms

Science.gov (United States)

Alzamora, Stella Maris; Guerrero, Sandra N.; Schenk, Marcela; Raffellini, Silvia; López-Malo, Aurelio

Minimal processing techniques for food preservation allow better retention of product flavor, texture, color, and nutrient content than comparable conventional treatments. A wide range of novel alternative physical factors have been intensely investigated in the last two decades. These physical factors can cause inactivation of microorganisms at ambient or sublethal temperatures (e.g., high hydrostatic pressure, pulsed electric fields, ultrasound, pulsed light, and ultraviolet light). These technologies have been reported to reduce microorganism population in foods while avoiding the deleterious effects of severe heating on quality. Among technologies, high-energy ultrasound (i.e., intensities higher than 1 W/cm2, frequencies between 18 and 100 kHz) has attracted considerable interest for food preservation applications (Mason et al., 1996; Povey and Mason, 1998).

Inactivation of VHSV by infiltration and salt under experimental conditions

DEFF Research Database (Denmark)

Skall, Helle Frank; Jørgensen, Claus; Olesen, Niels Jørgen

2014-01-01

At the moment the only legal method in Denmark to sanitize wastewater from fish cutting plants is by infiltration. To evaluate the inactivation effect of infiltration on VHSV an experimental examination was initiated. A column packed with gravel as top- and bottom layer (total of 22 cm) and a mid...... be a valuable method to sanitize VHSV infected water. Changes in temperature, pH, earth types in the area used for infiltration etc. may change the virus reduction, though. As some of the fish cutting plants are also smoking rainbow trout fillets, the question arose whether a brine solution will inactivate VHSV...

The specific role of FAM20C in amelogenesis.

Science.gov (United States)

Wang, X; Jung, J; Liu, Y; Yuan, B; Lu, Y; Feng, J Q; Qin, C

2013-11-01

Previously, we showed that Sox2-Cre;Fam20C(fl/fl) mice in which Fam20C was ubiquitously inactivated had severe defects in dentin, enamel, and bone, along with hypophosphatemia. It remains to be determined if the enamel defects in the mice with universal inactivation of Family with sequence similarity 20-C (FAM20C) were associated with the dentin defects and whether hypophosphatemia in the knockout mice contributed to the enamel defects. In this study, we crossed Fam20C(fl/fl) mice with keratin 14-Cre (K14-Cre) transgenic mice to specifically inactivate Fam20C in the epithelial cells, including the dental epithelial cells that are responsible for forming tooth enamel. X-ray, backscattered scanning electron microscopic, and histological analyses showed that the K14-Cre;Fam20C(fl/fl) mice had severe enamel and ameloblast defects, while their dentin and alveolar bone were not significantly affected. Accordingly, serum biochemistry of the K14-Cre;Fam20C(fl/fl) mice showed normal phosphate and FGF23 levels in the circulation. Analysis of these data indicates that, while FAM20C is a molecule essential to amelogenesis, its inactivation in the dental epithelium does not significantly affect dentinogenesis. Hypophosphatemia makes no significant contribution to the enamel defects in the mice with the ubiquitous deletion of Fam20C.

Inactivation model for disinfection of biofilms in drinking water

International Nuclear Information System (INIS)

Karlicki, A.; O'Leary, K.C.; Gagnon, G.A.

2002-01-01

The purpose of the project was to investigate experimentally the effects of free chlorine, monochloramine and chlorine dioxide on the removal of biofilm growth in water as it applies to drinking water in distribution systems. In particular, biofilm kill for a particular dosage of disinfectant was measured as a function of time for each disinfectant over a range of disinfectant concentrations. These results were used to formulate concentration-time (Ct) inactivation values for each disinfectant to compare the efficacy of the three disinfectants for biofilm control. The biofilm reactor system consisted of a 125 mL columns, each containing tightly packed 3 mm glass beads on which heterotrophic bacterial biofilm is established. Following an initial biofilm inoculation period, the glass beads were removed from the columns and placed into glass jars for disinfection with free chlorine, monochloramine and chlorine dioxide. Cell counts were determined on a time series basis with the goal of achieving a Ct inactivation model that is similar to models presently used for inactivation of suspended cells. Ultimately this research could be used to develop a rationale method for setting regulatory values for secondary disinfection in drinking water distribution systems, which presently in only a few states and provinces. (author)

Antimicrobial blue light inactivation of Methicillin-resistant Staphylococcus aureus

Science.gov (United States)

Wang, Yucheng; Dai, Tianhong; Gu, Ying

2016-10-01

Background: With the increasing emergence of multidrug-resistant (MDR) bacterial strains, there is a pressing need for the development of alternative treatment for infections. Antimicrobial blue light (aBL) has provided a simple and effective approach. Methods: We first investigated the effectiveness of aBL (415 nm) inactivation of USA300 LAClux (a communityacquired Methicillin-resistant Staphylococcus aureus strain) both in the planktonic and biofilm forms. The survival of the bacteria in suspensions was determined by serial dilution and that of the biofilm-embedded bacteria was determined by bioluminescence quantification. Using a mouse model of thermal burn infected with USA300 LAClux, we further assessed the effectiveness of aBL for treating localized infections. Bioluminescence imaging was performed to monitor in real time bacterial viability in vivo. Results: In vitro study showed that, for the planktonic counterpart of the bacteria or the 24-h-old biofilms, an irradiance of 55 mW/cm2 for 60 min resulted in a 4.61 log10 or 2.56 log10 inactivation, respectively. In vivo study using infected mouse burns demonstrated that a 2.56-log10 inactivation was achieved after 100-mW/cm2 irradiation for 62 min. Conclusions: aBL is a potential alternative approach for treating Methicillin-resistant Staphylococcus aureus infections.

Non-linear pressure/temperature-dependence of high pressure thermal inactivation of proteolytic Clostridium botulinum type B in foods.

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Maximilian B Maier

Full Text Available The effect of high pressure thermal (HPT processing on the inactivation of spores of proteolytic type B Clostridium botulinum TMW 2.357 in four differently composed low-acid foods (green peas with ham, steamed sole, vegetable soup, braised veal was studied in an industrially feasible pressure range and temperatures between 100 and 120°C. Inactivation curves exhibited rapid inactivation during compression and decompression followed by strong tailing effects. The highest inactivation (approx. 6-log cycle reduction was obtained in braised veal at 600 MPa and 110°C after 300 s pressure-holding time. In general, inactivation curves exhibited similar negative exponential shapes, but maximum achievable inactivation levels were lower in foods with higher fat contents. At high treatment temperatures, spore inactivation was more effective at lower pressure levels (300 vs. 600 MPa, which indicates a non-linear pressure/temperature-dependence of the HPT spore inactivation efficiency. A comparison of spore inactivation levels achievable using HPT treatments versus a conventional heat sterilization treatment (121.1°C, 3 min illustrates the potential of combining high pressures and temperatures to replace conventional retorting with the possibility to reduce the process temperature or shorten the processing time. Finally, experiments using varying spore inoculation levels suggested the presence of a resistant fraction comprising approximately 0.01% of a spore population as reason for the pronounced tailing effects in survivor curves. The loss of the high resistance properties upon cultivation indicates that those differences develop during sporulation and are not linked to permanent modifications at the genetic level.

Effects of track structure and cell inactivation on the calculation of heavy ion mutation rates in mammalian cells

Science.gov (United States)

Cucinotta, F. A.; Wilson, J. W.; Shavers, M. R.; Katz, R.

1996-01-01

It has long been suggested that inactivation severely effects the probability of mutation by heavy ions in mammalian cells. Heavy ions have observed cross sections of inactivation that approach and sometimes exceed the geometric size of the cell nucleus in mammalian cells. In the track structure model of Katz the inactivation cross section is found by summing an inactivation probability over all impact parameters from the ion to the sensitive sites within the cell nucleus. The inactivation probability is evaluated using the dose-response of the system to gamma-rays and the radial dose of the ions and may be equal to unity at small impact parameters for some ions. We show how the effects of inactivation may be taken into account in the evaluation of the mutation cross sections from heavy ions in the track structure model through correlation of sites for gene mutation and cell inactivation. The model is fit to available data for HPRT mutations in Chinese hamster cells and good agreement is found. The resulting calculations qualitatively show that mutation cross sections for heavy ions display minima at velocities where inactivation cross sections display maxima. Also, calculations show the high probability of mutation by relativistic heavy ions due to the radial extension of ions track from delta-rays in agreement with the microlesion concept. The effects of inactivation on mutations rates make it very unlikely that a single parameter such as LET or Z*2/beta(2) can be used to specify radiation quality for heavy ion bombardment.

Modeling the high pressure inactivation kinetics of Listeria monocytogenes on RTE cooked meat products

DEFF Research Database (Denmark)

Hereu, A.; Dalgaard, Paw; Garriga, M.

2012-01-01

High pressure (HP) inactivation curves of Listeria monocytogenes CTC1034 (ca. 107CFU/g) on sliced RTE cooked meat products (ham and mortadella) were obtained at pressures from 300 to 800MPa. A clear tail shape was observed at pressures above 450MPa and the log-linear with tail primary model...... provided the best fit to the HP-inactivation kinetics. The relationships between the primary kinetic parameters (log kmax and log Nres) and pressure treatments were described by a polynomial secondary model. To estimate HP-inactivation of L. monocytogenes in log (N/N0) over time, a one-step global fitting...

Theoretical studies on the inactivation mechanism of γ-aminobutyric acid aminotransferase.

Science.gov (United States)

Durak, A T; Gökcan, H; Konuklar, F A S

2011-07-21

The inactivation mechanism of γ-aminobutyric acid aminotransferase (GABA-AT) in the presence of γ-vinyl-aminobutyric acid, an anti-epilepsy drug, has been studied by means of theoretical calculations. Density functional theory methods have been applied to compare the three experimentally proposed inactivation mechanisms (Silverman et al., J. Biol. Chem., 2004, 279, 363). All the calculations were performed at the B3LYP/6-31+G(d,p) level of theory. Single point solvent calculations were carried out in water, by means of an integral equation formalism-polarizable continuum model (IEFPCM) at the B3LYP/6-31+G(d,p) level of theory. The present calculations provide an insight into the mechanistic preferences of the inactivation reaction of GABA-AT. The results also allow us to elucidate the key factors behind the mechanistic preferences. The computations also confirm the importance of explicit water molecules around the reacting center in the proton transfer steps.

Chemical Addressability of Ultraviolet-Inactivated Viral Nanoparticles (VNPs)

Science.gov (United States)

Rae, Chris; Koudelka, Kristopher J.; Destito, Giuseppe; Estrada, Mayra N.; Gonzalez, Maria J.; Manchester, Marianne

2008-01-01

Background Cowpea Mosaic Virus (CPMV) is increasingly being used as a nanoparticle platform for multivalent display of molecules via chemical bioconjugation to the capsid surface. A growing variety of applications have employed the CPMV multivalent display technology including nanoblock chemistry, in vivo imaging, and materials science. CPMV nanoparticles can be inexpensively produced from experimentally infected cowpea plants at high yields and are extremely stable. Although CPMV has not been shown to replicate in mammalian cells, uptake in mammalian cells does occur in vitro and in vivo. Thus, inactivation of the virus RNA genome is important for biosafety considerations, however the surface characteristics and chemical reactivity of the particles must be maintained in order to preserve chemical and structural functionality. Methodology/Principal Findings Short wave (254 nm) UV irradiation was used to crosslink the RNA genome within intact particles. Lower doses of UV previously reported to inactivate CPMV infectivity inhibited symptoms on inoculated leaves but did not prohibit systemic virus spread in plants, whereas higher doses caused aggregation of the particles and an increase in chemical reactivity further indicating broken particles. Intermediate doses of 2.0–2.5 J/cm2 were shown to maintain particle structure and chemical reactivity, and cellular binding properties were similar to CPMV-WT. Conclusions These studies demonstrate that it is possible to inactivate CPMV infectivity while maintaining particle structure and function, thus paving the way for further development of CPMV nanoparticles for in vivo applications. PMID:18830402

Chemical addressability of ultraviolet-inactivated viral nanoparticles (VNPs.

Directory of Open Access Journals (Sweden)

Chris Rae

2008-10-01

Full Text Available Cowpea Mosaic Virus (CPMV is increasingly being used as a nanoparticle platform for multivalent display of molecules via chemical bioconjugation to the capsid surface. A growing variety of applications have employed the CPMV multivalent display technology including nanoblock chemistry, in vivo imaging, and materials science. CPMV nanoparticles can be inexpensively produced from experimentally infected cowpea plants at high yields and are extremely stable. Although CPMV has not been shown to replicate in mammalian cells, uptake in mammalian cells does occur in vitro and in vivo. Thus, inactivation of the virus RNA genome is important for biosafety considerations, however the surface characteristics and chemical reactivity of the particles must be maintained in order to preserve chemical and structural functionality.Short wave (254 nm UV irradiation was used to crosslink the RNA genome within intact particles. Lower doses of UV previously reported to inactivate CPMV infectivity inhibited symptoms on inoculated leaves but did not prohibit systemic virus spread in plants, whereas higher doses caused aggregation of the particles and an increase in chemical reactivity further indicating broken particles. Intermediate doses of 2.0-2.5 J/cm(2 were shown to maintain particle structure and chemical reactivity, and cellular binding properties were similar to CPMV-WT.These studies demonstrate that it is possible to inactivate CPMV infectivity while maintaining particle structure and function, thus paving the way for further development of CPMV nanoparticles for in vivo applications.

Inhibition of Retinoblastoma Protein Inactivation

Science.gov (United States)

2017-11-01

CONTRACT NUMBER Inhibition of Retinoblastoma Protein Inactivation 5b. GRANT NUMBER W81XWH-14-1-0329 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Seth M...confirmed 108 compounds as giving a dose-response curve with at least 30% inhibition at 10 µM. The flowchart of hit progression is shown on the...Cancer Research Program under Award No. W81XWH-14-1-0329 to S.M.R. Opinions, interpretations, conclusions, and recommendations are those of the author

No evidence for functional inactivation of wild-type p53 protein by MDM2 overexpression in gastric carcinogenesis

NARCIS (Netherlands)

Blok, P.; Craanen, M. E.; Dekker, W.; Offerhaus, G. J.; Tytgat, G. N.

1998-01-01

Inactivation of wild-type p53 during gastric carcinogenesis is usually caused by mutations within exons 5-8 of the p53 gene leading to mutated, usually immunohistochemically detectable p53 proteins. However, functional inactivation of wild-type p53, mimicking mutational inactivation, may also result

Inactivation of human immunodeficiency virus (HIV) by ionizing radiation in body fluids and serological evidence

International Nuclear Information System (INIS)

Bigbee, P.D.; Sarin, P.S.; Humphreys, J.C.; Eubanks, W.G.; Sun, D.; Hocken, D.G.; Thornton, A.; Adams, D.E.; Simic, M.G.

1989-01-01

A method to use ionizing radiation to inactivate HIV (Human Immunodeficiency Virus) in human body fluids was studied in an effort to reduce the risk of accidental infection to forensic science laboratory workers. Experiments conducted indicate that an X-ray absorbed dose of 25 krad was required to completely inactivate HIV. This does not alter forensically important constituents such as enzymes and proteins in body fluids. This method of inactivation of HIV cannot be used on body fluids which will be subjected to deoxyribonucleic acid (DNA) typing

THERMODYNAMICS AND KINETICS OF THERMAL INACTIVATION OF PEROXIDASE FROM MANGOSTEEN (GARCINIA MANGOSTANA L. PERICARP

Directory of Open Access Journals (Sweden)

MAHSA ZIABAKHSH DEYLAMI

2014-06-01

Full Text Available Mangosteen (Garcinia mangostana L. pericarp is an abundant source of phytochemicals. Blanching prior to further process stabilizes these valuable compounds. In this research, crude peroxidase (POD was extracted from mangosteen peel using Triton X-100. Kinetics of POD inactivation was studied over temperature range of 60- 100°C. The inactivation kinetics followed a monophasic first-order model with k values between 1.93×10-2- 8.14×10-2 min-1. The decreasing trend of k values with increasing temperature indicates a faster inactivation of peroxidase from mangosteen pericarp at higher temperatures. The activation energy (Ea of 35.06 kJ/mol was calculated from the slope of Arrhenius plot. Thermodynamic parameters (∆H, ∆G, ∆S for inactivation of peroxidase at different temperatures (60-100°C were studied in detail. The results of this research will help to design pre-processing conditions of mangosteen pericarp as a source of antioxidants.

Inactivation of hemopoietic stem cells by lymphocytes as related to genotype of interacting cells

Energy Technology Data Exchange (ETDEWEB)

Petrov, R V; Seslavina, L S; Panteleev, E I; Egorova, O S

1975-05-01

Inoculation of a mixture of bone marrow cells with allogeneic lymphocytes into irradiated mice of inbred strains or into F/sub 1/ hybrids results in the depression of bone marrow cell proliferation in the spleen of the recipient: the effect of inactivation of nonsyngeneic stem cells. The inactivation of stem cells by allogeneic lymphocytes can be detected in all tested combinations of mice strains - donors of lymphocytes and bone marrow cells and mice - recipients but the degree of inactivation differs and depends on the genotype of cell donors rather than on the genotype of the recipient. Lymphocytes of some mice strains (haplotypes H-2sup(k) and H-2sup(a)) are more active killers of bone marrow cells as compared with lymphocytes of other strains (hyplotypes H-2sup(b) and H-2sup(d)). Probably, the degree of stem cells inactivation by lymphocytes depends on the differences of their histocompatibility in H-2 system.

Wastewater disinfection by peracetic acid: assessment of models for tracking residual measurements and inactivation.

Science.gov (United States)

Santoro, Domenico; Gehr, Ronald; Bartrand, Timothy A; Liberti, Lorenzo; Notarnicola, Michele; Dell'Erba, Adele; Falsanisi, Dario; Haas, Charles N

2007-07-01

With its potential for low (if any) disinfection byproduct formation and easy retrofit for chlorine contactors, peracetic acid (PAA) or use of PAA in combination with other disinfectant technologies may be an attractive alternative to chlorine-based disinfection. Examples of systems that might benefit from use of PAA are water reuse schemes or plants discharging to sensitive receiving water bodies. Though PAA is in use in numerous wastewater treatment plants in Europe, its chemical kinetics, microbial inactivation rates, and mode of action against microorganisms are not thoroughly understood. This paper presents results from experimental studies of PAA demand, PAA decay, and microbial inactivation, with a complementary modeling analysis. Model results are used to evaluate techniques for measurement of PAA concentration and to develop hypotheses regarding the mode of action of PAA in bacterial inactivation. Kinetic and microbial inactivation rate data were collected for typical wastewaters and may be useful for engineers in evaluating whether to convert from chlorine to PAA disinfection.

X-ray induced inactivation of the capacity for photosynthetic oxygen evolution and nitrate reduction in blue-green algae

International Nuclear Information System (INIS)

Stevens, S.E. Jr.; Simic, M.G.; Rao, V.S.K.

1975-01-01

The level of inactivation of oxygen evolving photosynthesis in the green alga, Chlorella pyrenoidosa was 12 percent in N 2 at a dose of 100 krad of x irradiation. Under similar conditions, as well as under O 2 , there resulted a 20 percent inactivation of the same function in the blue-green algae, Agmenellum quadruplicatum, strains PR-6 and AQ-6. Nitrate reduction capacity in the mutant AQ-6 was inactivated to 40 percent in N 2 and to 7 percent in O 2 . Catalase and formate provided some protection from irradiation in O 2 , suggesting some inactivation by H 2 O 2 . Most of the damage to the nitrate reduction system resulted from the direct action of x irradiation on a constitutive subunit of the nitrate reductase complex. Moreover, the slight inactivation of the O 2 evolving system, a function which is associated with photosystem II, cannot account for the inactivation of nitrate reduction

Inactivation of bacterial biofilms using visible-light-activated unmodified ZnO nanorods

Science.gov (United States)

Aponiene, Kristina; Serevičius, Tomas; Luksiene, Zivile; Juršėnas, Saulius

2017-09-01

Various zinc oxide (ZnO) nanostructures are widely used for photocatalytic antibacterial applications. Since ZnO possesses a wide bandgap, it is believed that only UV light may efficiently assist bacterial inactivation, and diverse crystal lattice modifications should be applied in order to narrow the bandgap for efficient visible-light absorption. In this work we show that even unmodified ZnO nanorods grown by an aqueous chemical growth technique are found to possess intrinsic defects that can be activated by visible light (λ = 405 nm) and successfully applied for total inactivation of various highly resistant bacterial biofilms rather than more sensitive planktonic bacteria. Time-resolved fluorescence analysis has revealed that visible-light excitation creates long-lived charge carriers (τ > 1 μs), which might be crucial for destructive biochemical reactions achieving significant bacterial biofilm inactivation. ZnO nanorods covered with bacterial biofilms of Enterococcus faecalis MSCL 302 after illumination by visible light (λ = 405 nm) were inactivated by 2 log, and Listeria monocytogenes ATCL3C 7644 and Escherichia coli O157:H7 biofilms by 4 log. Heterogenic waste-water microbial biofilms, consisting of a mixed population of mesophilic bacteria after illumination with visible light were also completely destroyed.

Polyelectrolyte-Functionalized Nanofiber Mats Control the Collection and Inactivation of Escherichia coli

Directory of Open Access Journals (Sweden)

Katrina A. Rieger

2016-04-01

Full Text Available Quantifying the effect that nanofiber mat chemistry and hydrophilicity have on microorganism collection and inactivation is critical in biomedical applications. In this study, the collection and inactivation of Escherichia coli K12 was examined using cellulose nanofiber mats that were surface-functionalized using three polyelectrolytes: poly (acrylic acid (PAA, chitosan (CS, and polydiallyldimethylammonium chloride (pDADMAC. The polyelectrolyte functionalized nanofiber mats retained the cylindrical morphology and average fiber diameter (~0.84 µm of the underlying cellulose nanofibers. X-ray photoelectron spectroscopy (XPS and contact angle measurements confirmed the presence of polycations or polyanions on the surface of the nanofiber mats. Both the control cellulose and pDADMAC-functionalized nanofiber mats exhibited a high collection of E. coli K12, which suggests that mat hydrophilicity may play a larger role than surface charge on cell collection. While the minimum concentration of polycations needed to inhibit E. coli K12 was 800 µg/mL for both CS and pDADMAC, once immobilized, pDADMAC-functionalized nanofiber mats exhibited a higher inactivation of E. coli K12, (~97%. Here, we demonstrate that the collection and inactivation of microorganisms by electrospun cellulose nanofiber mats can be tailored through a facile polyelectrolyte functionalization process.

Polyelectrolyte-Functionalized Nanofiber Mats Control the Collection and Inactivation of Escherichia coli

Science.gov (United States)

Rieger, Katrina A.; Porter, Michael; Schiffman, Jessica D.

2016-01-01

Quantifying the effect that nanofiber mat chemistry and hydrophilicity have on microorganism collection and inactivation is critical in biomedical applications. In this study, the collection and inactivation of Escherichia coli K12 was examined using cellulose nanofiber mats that were surface-functionalized using three polyelectrolytes: poly (acrylic acid) (PAA), chitosan (CS), and polydiallyldimethylammonium chloride (pDADMAC). The polyelectrolyte functionalized nanofiber mats retained the cylindrical morphology and average fiber diameter (~0.84 µm) of the underlying cellulose nanofibers. X-ray photoelectron spectroscopy (XPS) and contact angle measurements confirmed the presence of polycations or polyanions on the surface of the nanofiber mats. Both the control cellulose and pDADMAC-functionalized nanofiber mats exhibited a high collection of E. coli K12, which suggests that mat hydrophilicity may play a larger role than surface charge on cell collection. While the minimum concentration of polycations needed to inhibit E. coli K12 was 800 µg/mL for both CS and pDADMAC, once immobilized, pDADMAC-functionalized nanofiber mats exhibited a higher inactivation of E. coli K12, (~97%). Here, we demonstrate that the collection and inactivation of microorganisms by electrospun cellulose nanofiber mats can be tailored through a facile polyelectrolyte functionalization process. PMID:28773422

Immunotherapy with internally inactivated virus loaded dendritic cells boosts cellular immunity but does not affect feline immunodeficiency virus infection course

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Pistello Mauro

2008-04-01

Full Text Available Abstract Immunotherapy of feline immunodeficiency virus (FIV-infected cats with monocyte-derived dendritic cells (MDCs loaded with aldrithiol-2 (AT2-inactivated homologous FIV was performed. Although FIV-specific lymphoproliferative responses were markedly increased, viral loads and CD4+ T cell depletion were unaffected, thus indicating that boosting antiviral cell-mediated immunity may not suffice to modify infection course appreciably.

Covalent Allosteric Inactivation of Protein Tyrosine Phosphatase 1B (PTP1B) by an Inhibitor-Electrophile Conjugate.

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Punthasee, Puminan; Laciak, Adrian R; Cummings, Andrea H; Ruddraraju, Kasi Viswanatharaju; Lewis, Sarah M; Hillebrand, Roman; Singh, Harkewal; Tanner, John J; Gates, Kent S

2017-04-11

Protein tyrosine phosphatase 1B (PTP1B) is a validated drug target, but it has proven difficult to develop medicinally useful, reversible inhibitors of this enzyme. Here we explored covalent strategies for the inactivation of PTP1B using a conjugate composed of an active site-directed 5-aryl-1,2,5-thiadiazolidin-3-one 1,1-dioxide inhibitor connected via a short linker to an electrophilic α-bromoacetamide moiety. Inhibitor-electrophile conjugate 5a caused time-dependent loss of PTP1B activity consistent with a covalent inactivation mechanism. The inactivation occurred with a second-order rate constant of (1.7 ± 0.3) × 10 2 M -1 min -1 . Mass spectrometric analysis of the inactivated enzyme indicated that the primary site of modification was C121, a residue distant from the active site. Previous work provided evidence that covalent modification of the allosteric residue C121 can cause inactivation of PTP1B [Hansen, S. K., Cancilla, M. T., Shiau, T. P., Kung, J., Chen, T., and Erlanson, D. A. (2005) Biochemistry 44, 7704-7712]. Overall, our results are consistent with an unusual enzyme inactivation process in which noncovalent binding of the inhibitor-electrophile conjugate to the active site of PTP1B protects the nucleophilic catalytic C215 residue from covalent modification, thus allowing inactivation of the enzyme via selective modification of allosteric residue C121.

Structure of 6-diazo-5-oxo-norleucine-bound human gamma-glutamyl transpeptidase 1, a novel mechanism of inactivation.

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Terzyan, Simon S; Cook, Paul F; Heroux, Annie; Hanigan, Marie H

2017-06-01

Intense efforts are underway to identify inhibitors of the enzyme gamma-glutamyl transpeptidase 1 (GGT1) which cleaves extracellular gamma-glutamyl compounds and contributes to the pathology of asthma, reperfusion injury and cancer. The glutamate analog, 6-diazo-5-oxo-norleucine (DON), inhibits GGT1. DON also inhibits many essential glutamine metabolizing enzymes rendering it too toxic for use in the clinic as a GGT1 inhibitor. We investigated the molecular mechanism of human GGT1 (hGGT1) inhibition by DON to determine possible strategies for increasing its specificity for hGGT1. DON is an irreversible inhibitor of hGGT1. The second order rate constant of inactivation was 0.052 mM -1 min -1 and the K i was 2.7 ± 0.7 mM. The crystal structure of DON-inactivated hGGT1 contained a molecule of DON without the diazo-nitrogen atoms in the active site. The overall structure of the hGGT1-DON complex resembled the structure of the apo-enzyme; however, shifts were detected in the loop forming the oxyanion hole and elements of the main chain that form the entrance to the active site. The structure of hGGT1-DON complex revealed two covalent bonds between the enzyme and inhibitor which were part of a six membered ring. The ring included the OG atom of Thr381, the reactive nucleophile of hGGT1 and the α-amine of Thr381. The structure of DON-bound hGGT1 has led to the discovery of a new mechanism of inactivation by DON that differs from its inactivation of other glutamine metabolizing enzymes, and insight into the activation of the catalytic nucleophile that initiates the hGGT1 reaction. © 2017 The Protein Society.

Inactivation of rabies diagnostic reagents by gamma radiation

International Nuclear Information System (INIS)

Gamble, W.C.; Chappell, W.A.; George, E.H.

1980-01-01

Treatment of CVS-11 rabies adsorbing suspensions and street rabies infected mouse brains with gamma radiation resulted in inactivated reagents that are safer to distribute and use. These irradiated reagents were as sensitive and reactive as the nonirradiated control reagents

Fetal calf serum heat inactivation and lipopolysaccharide contamination influence the human T lymphoblast proteome and phosphoproteome

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Rahman Hazir

2011-11-01

Full Text Available Abstract Background The effects of fetal calf serum (FCS heat inactivation and bacterial lipopolysaccharide (LPS contamination on cell physiology have been studied, but their effect on the proteome of cultured cells has yet to be described. This study was undertaken to investigate the effects of heat inactivation of FCS and LPS contamination on the human T lymphoblast proteome. Human T lymphoblastic leukaemia (CCRF-CEM cells were grown in FCS, either non-heated, or heat inactivated, having low ( Results A total of four proteins (EIF3M, PRS7, PSB4, and SNAPA were up-regulated when CCRF-CEM cells were grown in media supplemented with heat inactivated FCS (HE as compared to cells grown in media with non-heated FCS (NHE. Six proteins (TCPD, ACTA, NACA, TCTP, ACTB, and ICLN displayed a differential phosphorylation pattern between the NHE and HE groups. Compared to the low concentration LPS group, regular levels of LPS resulted in the up-regulation of three proteins (SYBF, QCR1, and SUCB1. Conclusion The present study provides new information regarding the effect of FCS heat inactivation and change in FCS-LPS concentration on cellular protein expression, and post-translational modification in human T lymphoblasts. Both heat inactivation and LPS contamination of FCS were shown to modulate the expression and phosphorylation of proteins involved in basic cellular functions, such as protein synthesis, cytoskeleton stability, oxidative stress regulation and apoptosis. Hence, the study emphasizes the need to consider both heat inactivation and LPS contamination of FCS as factors that can influence the T lymphoblast proteome.

Membrane permeabilization in relation to inactivation kinetics of Lactobacillus species due to pulsed electric fields.

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Wouters, P C; Bos, A P; Ueckert, J

2001-07-01

Membrane permeabilization due to pulsed electric field (PEF) treatment of gram-positive Lactobacillus cells was investigated by using propidium iodide uptake and single-cell analysis with flow cytometry. Electric field strength, energy input, treatment time, and growth phase affected membrane permeabilization of Lactobacillus plantarum during PEF treatment. A correlation between PEF inactivation and membrane permeabilization of L. plantarum cells was demonstrated, whereas no relationship was observed between membrane permeabilization and heat inactivation. The same results were obtained with a Lactobacillus fermentum strain, but the latter organism was more PEF resistant and exhibited less membrane permeabilization, indicating that various bacteria have different responses to PEF treatment. While membrane permeabilization was the main factor involved in the mechanism of inactivation, the growth phase and the acidity of the environment also influenced inactivation. By using flow cytometry it was possible to sort cells in the L. plantarum population based on different cell sizes and shapes, and the results were confirmed by image analysis. An apparent effect of morphology on membrane permeabilization was observed, and larger cells were more easily permeabilized than smaller cells. In conclusion, our results indicate that the ability of PEF treatment to cause membrane permeabilization is an important factor in determining inactivation. This finding should have an effect on the final choice of the processing parameters used so that all microorganisms can be inactivated and, consequently, on the use of PEF treatment as an alternative method for preserving food products.

Membrane Permeabilization in Relation to Inactivation Kinetics of Lactobacillus Species due to Pulsed Electric Fields

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Wouters, Patrick C.; Bos, Ad P.; Ueckert, Joerg

2001-01-01

Membrane permeabilization due to pulsed electric field (PEF) treatment of gram-positive Lactobacillus cells was investigated by using propidium iodide uptake and single-cell analysis with flow cytometry. Electric field strength, energy input, treatment time, and growth phase affected membrane permeabilization of Lactobacillus plantarum during PEF treatment. A correlation between PEF inactivation and membrane permeabilization of L. plantarum cells was demonstrated, whereas no relationship was observed between membrane permeabilization and heat inactivation. The same results were obtained with a Lactobacillus fermentum strain, but the latter organism was more PEF resistant and exhibited less membrane permeabilization, indicating that various bacteria have different responses to PEF treatment. While membrane permeabilization was the main factor involved in the mechanism of inactivation, the growth phase and the acidity of the environment also influenced inactivation. By using flow cytometry it was possible to sort cells in the L. plantarum population based on different cell sizes and shapes, and the results were confirmed by image analysis. An apparent effect of morphology on membrane permeabilization was observed, and larger cells were more easily permeabilized than smaller cells. In conclusion, our results indicate that the ability of PEF treatment to cause membrane permeabilization is an important factor in determining inactivation. This finding should have an effect on the final choice of the processing parameters used so that all microorganisms can be inactivated and, consequently, on the use of PEF treatment as an alternative method for preserving food products. PMID:11425727

Epitope mapping and biological function analysis of antibodies produced by immunization of mice with an inactivated Chinese isolate of severe acute respiratory syndrome-associated coronavirus (SARS-CoV)

International Nuclear Information System (INIS)

Chou, Te-hui W.; Wang, Shixia; Sakhatskyy, Pavlo V.; Mboudoudjeck, Innocent; Lawrence, John M.; Huang Song; Coley, Scott; Yang Baoan; Li Jiaming; Zhu Qingyu; Lu Shan

2005-01-01

Inactivated severe acute respiratory syndrome-associated coronavirus (SARS-CoV) has been tested as a candidate vaccine against the re-emergence of SARS. In order to understand the efficacy and safety of this approach, it is important to know the antibody specificities generated with inactivated SARS-CoV. In the current study, a panel of twelve monoclonal antibodies (mAbs) was established by immunizing Balb/c mice with the inactivated BJ01 strain of SARS-CoV isolated from the lung tissue of a SARS-infected Chinese patient. These mAbs could recognize SARS-CoV-infected cells by immunofluorescence analysis (IFA). Seven of them were mapped to the specific segments of recombinant spike (S) protein: six on S1 subunit (aa 12-798) and one on S2 subunit (aa 797-1192). High neutralizing titers against SARS-CoV were detected with two mAbs (1A5 and 2C5) targeting at a subdomain of S protein (aa 310-535), consistent with the previous report that this segment of S protein contains the major neutralizing domain. Some of these S-specific mAbs were able to recognize cleaved products of S protein in SARS-CoV-infected Vero E6 cells. None of the remaining five mAbs could recognize either of the recombinant S, N, M, or E antigens by ELISA. This study demonstrated that the inactivated SARS-CoV was able to preserve the immunogenicity of S protein including its major neutralizing domain. The relative ease with which these mAbs were generated against SARS-CoV virions further supports that subunit vaccination with S constructs may also be able to protect animals and perhaps humans. It is somewhat unexpected that no N-specific mAbs were identified albeit anti-N IgG was easily identified in SARS-CoV-infected patients. The availability of this panel of mAbs also provided potentially useful agents with applications in therapy, diagnosis, and basic research of SARS-CoV

Systems Biology of Immune Response to Live and Inactivated Dengue Virus Vaccines

Science.gov (United States)

2017-09-01

AWARD NUMBER: W81XWH-16-2-0032 TITLE: Systems Biology of Immune Response to Live and Inactivated Dengue Virus Vaccines PRINCIPAL INVESTIGATOR...CONTRACT NUMBER Systems Biology of Immune Response to Live and Inactivated Dengue Virus Vaccines 5b. GRANT NUMBER W81XWH-16-2-0032 5c. PROGRAM ELEMENT...cell) responses will be measured using molecular and cellular approaches and the data analyzed using a systems biology approach. During the first

Endotoxin inactivation via steam-heat treatment in dilute simethicone emulsions used in biopharmaceutical processes.

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Britt, Keith A; Galvin, Jeffrey; Gammell, Patrick; Nti-Gyabaah, Joseph; Boras, George; Kolwyck, David; Ramirez, José G; Presente, Esther; Naugle, Gregory

2014-01-01

Simethicone emulsion is used to regulate foaming in cell culture operations in biopharmaceutical processes. It is also a potential source of endotoxin contamination. The inactivation of endotoxins in dilute simethicone emulsions was assessed as a function of time at different steam temperatures using a Limulus amebocyte lysate kinetic chromogenic technique. Endotoxin inactivation from steam-heat treatment was fit to a four-parameter double exponential decay model, which indicated that endotoxin inactivation was biphasic, consisting of fast and slow regimes. In the fast regime, temperature-related effects were dominant. Transitioning into the slow regime, the observed temperature dependence diminished, and concentration-related effects became increasingly significant. The change in the Gibbs free energy moving through the transition state indicated that a large energy barrier must be overcome for endotoxin inactivation to occur. The corresponding Arrhenius pre-exponential factor was >10(12) s(-1) suggesting that endotoxins in aqueous solution exist as aggregates. The disorder associated with the endotoxin inactivation reaction pathway was assessed via the change in entropy moving through the transition state. This quantity was positive indicating that endotoxin inactivation may result from hydrolysis of individual endotoxin molecules, which perturbs the conformation of endotoxin aggregates, thereby modulating the biological activity observed. Steam-heat treatment decreased endotoxin levels by 1-2 logarithm (log) reduction (LRV), which may be practically relevant depending on incoming raw material endotoxin levels. Antifoam efficiency and cell culture performance were negligibly impacted following steam-heat treatment. The results from this study show that steam-heat treatment is a viable endotoxin control strategy that can be implemented to support large-scale biopharmaceutical manufacturing. © 2014 American Institute of Chemical Engineers.

Selection of inactivation medium for fungal spores in clinical wastes by supercritical carbon dioxide.

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Noman, Efaq; Norulaini Nik Ab Rahman, Nik; Al-Gheethi, Adel; Nagao, Hideyuki; Talip, Balkis A; Ab Kadir, Omar

2018-05-21

The present study aimed to select the best medium for inactivation of Aspergillus fumigatus, Aspergillus spp. in section Nigri, A. niger, A. terreus var. terreus, A. tubingensis, Penicillium waksmanii, P. simplicissimum, and Aspergillus sp. strain no. 145 spores in clinical wastes by using supercritical carbon dioxide (SC-CO 2 ). There were three types of solutions used including normal saline, seawater, distilled water, and physiological saline with 1% of methanol; each solution was tested at 5, 10, and 20 mL of the water contents. The experiments were conducted at the optimum operating parameters of supercritical carbon dioxide (30 MPa, 75 °C, 90 min). The results showed that the inactivation rate was more effective in distilled water with the presence of 1% methanol (6 log reductions). Meanwhile, the seawater decreases inactivation rate more than normal saline (4.5 vs. 5.1 log reduction). On the other hand, the experiments performed with different volumes of distilled water (5, 10, and 20 mL) indicated that A. niger spores were completely inactivated with 10 mL of distilled water. The inactivation rate of fungal spores decreased from 6 to 4.5 log as the amount of distilled water increased from 10 to 20 mL. The analysis for the spore morphology of A. fumigatus and Aspergillus spp. in section Nigri using scanning electron microscopy (SEM) has revealed the role of temperature and pressure in the SC-CO 2 in the destruction of the cell walls of the spores. It can be concluded that the distilled water represent the best medium for inactivation of fungal spores in the clinical solid wastes by SC-CO 2 .

Substrate-induced inactivation of the OXA2 beta-lactamase.

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Ledent, P; Frère, J M

1993-01-01

The hydrolysis time courses of 22 beta-lactam antibiotics by the class D OXA2 beta-lactamase were studied. Among these, only three appeared to correspond to the integrated Henri-Michaelis equation. 'Burst' kinetics, implying branched pathways, were observed with most penicillins, cephalosporins and with flomoxef and imipenem. Kinetic parameters characteristic of the different phases of the hydrolysis were determined for some substrates. Mechanisms generally accepted to explain such reversible partial inactivations involving branches at either the free enzyme or the acyl-enzyme were inadequate to explain the enzyme behaviour. The hydrolysis of imipenem was characterized by the occurrence of two 'bursts', and that of nitrocefin by a partial substrate-induced inactivation complicated by a competitive inhibition by the hydrolysis product. PMID:8240304

Inactivation of Template-Directed Misfolding of Infectious Prion Protein by Ozone

Science.gov (United States)

Ding, Ning; Price, Luke M.; Braithwaite, Shannon L.; Balachandran, Aru; Belosevic, Miodrag

2012-01-01

Misfolded prions (PrPSc) are well known for their resistance to conventional decontamination processes. The potential risk of contamination of the water environment, as a result of disposal of specified risk materials (SRM), has raised public concerns. Ozone is commonly utilized in the water industry for inactivation of microbial contaminants and was tested in this study for its ability to inactivate prions (263K hamster scrapie = PrPSc). Treatment variables included initial ozone dose (7.6 to 25.7 mg/liter), contact time (5 s and 5 min), temperature (4°C and 20°C), and pH (pH 4.4, 6.0, and 8.0). Exposure of dilute suspensions of the infected 263K hamster brain homogenates (IBH) (0.01%) to ozone resulted in the in vitro destruction of the templating properties of PrPSc, as measured by the protein misfolding cyclic amplification (PMCA) assay. The highest levels of prion inactivation (≥4 log10) were observed with ozone doses of 13.0 mg/liter, at pH 4.4 and 20°C, resulting in a CT (the product of residual ozone concentration and contact time) value as low as 0.59 mg · liter−1 min. A comparison of ozone CT requirements among various pathogens suggests that prions are more susceptible to ozone degradation than some model bacteria and protozoa and that ozone treatment may be an effective solution for inactivating prions in water and wastewater. PMID:22138993

Unilateral lateral entorhinal inactivation impairs memory expression in trace eyeblink conditioning.

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Stephanie E Tanninen

Full Text Available Memory in trace eyeblink conditioning is mediated by an inter-connected network that involves the hippocampus (HPC, several neocortical regions, and the cerebellum. This network reorganizes after learning as the center of the network shifts from the HPC to the medial prefrontal cortex (mPFC. Despite the network reorganization, the lateral entorhinal cortex (LEC plays a stable role in expressing recently acquired HPC-dependent memory as well as remotely acquired mPFC-dependent memory. Entorhinal involvement in recent memory expression may be attributed to its previously proposed interactions with the HPC. In contrast, it remains unknown how the LEC participates in memory expression after the network disengages from the HPC. The present study tested the possibility that the LEC and mPFC functionally interact during remote memory expression by examining the impact of pharmacological inactivation of the LEC in one hemisphere and the mPFC in the contralateral hemisphere on memory expression in rats. Memory expression one day and one month after learning was significantly impaired after LEC-mPFC inactivation; however, the degree of impairment was comparable to that after unilateral LEC inactivation. Unilateral mPFC inactivation had no effect on recent or remote memory expression. These results suggest that the integrity of the LEC in both hemispheres is necessary for memory expression. Functional interactions between the LEC and mPFC should therefore be tested with an alternative design.

Sexy transgenes: the impact of gene transfer and gene inactivation technologies on the understanding of mammalian sex determination.

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Vaiman, Daniel

2003-06-01

Amongst the various developmental pathways ending in a sound mammal, sex determination presents the peculiarity of a choice between two equally viable options: female or male. Therefore, destroying a 'male-determining gene' or a 'female-determining gene' should generally not be lethal. Genetic sex determination is divided into two consecutive steps: construction of the bipotential gonad, and then sex determination per se. The genes involved in the first step are in fact involved in the development of various body compartments, and their mutation is generally far from innocuous. From transgenic and inactivation studies carried out on the laboratory mouse, a complete picture of the two steps is beginning to emerge, where the gonad itself and the necessary ducts are shown to evolve in a very coordinate way, with well-defined sex-specificities. Compared with testis determination, the ovarian side of the picture is still relatively empty, but this situation can change rapidly as candidate ovarian genes for inactivation studies are beginning to be identified.

Inactivation of murine norovirus by chemical biocides on stainless steel

Science.gov (United States)

2009-01-01

Background Human norovirus (NoV) causes more than 80% of nonbacterial gastroenteritis in Europe and the United States. NoV transmission via contaminated surfaces may be significant for the spread of viruses. Therefore, measures for prevention and control, such as surface disinfection, are necessary to interrupt the dissemination of human NoV. Murine norovirus (MNV) as a surrogate for human NoV was used to study the efficacy of active ingredients of chemical disinfectants for virus inactivation on inanimate surfaces. Methods The inactivating properties of different chemical biocides were tested in a quantitative carrier test with stainless steel discs without mechanical action. Vacuum-dried MNV was exposed to different concentrations of alcohols, peracetic acid (PAA) or glutaraldehyde (GDA) for 5 minutes exposure time. Detection of residual virus was determined by endpoint-titration on RAW 264.7 cells. Results PAA [1000 ppm], GDA [2500 ppm], ethanol [50% (v/v)] and 1-propanol [30% (v/v)] were able to inactivate MNV under clean conditions (0.03% BSA) on the carriers by ≥ 4 log10 within 5 minutes exposure time, whereas 2-propanol showed a reduced effectiveness even at 60% (v/v). Furthermore, there were no significant differences in virus reduction whatever interfering substances were used. When testing with ethanol, 1- and 2-propanol, results under clean conditions were nearly the same as in the presence of dirty conditions (0.3% BSA plus 0.3% erythrocytes). Conclusion Products based upon PAA, GDA, ethanol and 1-propanol should be used for NoV inactivation on inanimate surfaces. Our data provide valuable information for the development of strategies to control NoV transmission via surfaces. PMID:19583832

Inactivation of murine norovirus by chemical biocides on stainless steel

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Steinmann Jörg

2009-07-01

Full Text Available Abstract Background Human norovirus (NoV causes more than 80% of nonbacterial gastroenteritis in Europe and the United States. NoV transmission via contaminated surfaces may be significant for the spread of viruses. Therefore, measures for prevention and control, such as surface disinfection, are necessary to interrupt the dissemination of human NoV. Murine norovirus (MNV as a surrogate for human NoV was used to study the efficacy of active ingredients of chemical disinfectants for virus inactivation on inanimate surfaces. Methods The inactivating properties of different chemical biocides were tested in a quantitative carrier test with stainless steel discs without mechanical action. Vacuum-dried MNV was exposed to different concentrations of alcohols, peracetic acid (PAA or glutaraldehyde (GDA for 5 minutes exposure time. Detection of residual virus was determined by endpoint-titration on RAW 264.7 cells. Results PAA [1000 ppm], GDA [2500 ppm], ethanol [50% (v/v] and 1-propanol [30% (v/v] were able to inactivate MNV under clean conditions (0.03% BSA on the carriers by ≥ 4 log10 within 5 minutes exposure time, whereas 2-propanol showed a reduced effectiveness even at 60% (v/v. Furthermore, there were no significant differences in virus reduction whatever interfering substances were used. When testing with ethanol, 1- and 2-propanol, results under clean conditions were nearly the same as in the presence of dirty conditions (0.3% BSA plus 0.3% erythrocytes. Conclusion Products based upon PAA, GDA, ethanol and 1-propanol should be used for NoV inactivation on inanimate surfaces. Our data provide valuable information for the development of strategies to control NoV transmission via surfaces.

Inactivation of possible microorganism food contaminants on packaging foils using nonthermal plasma and hydrogen peroxide

International Nuclear Information System (INIS)

Scholtz, V.; Khun, J.; Soušková, H.; Čeřovský, M.

2015-01-01

The inactivation effect of nonthermal plasma generated in electric discharge burning in air atmosphere with water or hydrogen peroxide aerosol for the application to the microbial decontamination of packaging foils is studied. The microbial inactivation is studied on two bacterial, two yeasts, and two filamentous micromycete species. The inactivation of all contaminating microorganisms becomes on the area of full 8.5 cm in diameter circular sample after short times of several tens of seconds. Described apparatus may present a possible alternative method of microbial decontamination of food packaging material or other thermolabile materials

Inactivation of possible microorganism food contaminants on packaging foils using nonthermal plasma and hydrogen peroxide

Energy Technology Data Exchange (ETDEWEB)

Scholtz, V., E-mail: Vladimir.Scholtz@vscht.cz; Khun, J. [Institute of Chemical Technology in Prague, Department of Physics and Measurements, Faculty of Chemical Engineering (Czech Republic); Soušková, H. [Institute of Chemical Technology in Prague, Department of Computing and Control Engineering, Faculty of Chemical Engineering (Czech Republic); Čeřovský, M. [Institute of Chemical Technology in Prague, Department of Food Preservation, Faculty of Food and Biochemical Technology (Czech Republic)

2015-07-15

The inactivation effect of nonthermal plasma generated in electric discharge burning in air atmosphere with water or hydrogen peroxide aerosol for the application to the microbial decontamination of packaging foils is studied. The microbial inactivation is studied on two bacterial, two yeasts, and two filamentous micromycete species. The inactivation of all contaminating microorganisms becomes on the area of full 8.5 cm in diameter circular sample after short times of several tens of seconds. Described apparatus may present a possible alternative method of microbial decontamination of food packaging material or other thermolabile materials.

Application of alpha microdosimetry in possible differentiation of inactivation effect from malignant cell transformation

International Nuclear Information System (INIS)

Sedlak, A.

1984-01-01

The model is described with a certain threshold value of specific energy z 0 independent of the linear transfer of energy (LTE) whose exceedance would result in the inactivation of the cell. The survival curves may be fitted to distribution function F(z 0 ,D). The final relationship is described by the linear dependence of quotient L 3 /D 37 on L 2 . The survival curves in low and high LTE are given. It may be assumed that at high LTE there exists a certain probability of survival even after passage of a densely ionizing particle through the cell nucleus. (E.S.)

Effects of blue or violet light on the inactivation of Staphylococcus aureus by riboflavin-5'-phosphate photolysis.

Science.gov (United States)

Wong, Tak-Wah; Cheng, Chien-Wei; Hsieh, Zong-Jhe; Liang, Ji-Yuan

2017-08-01

The light sensitive compound riboflavin-5'-phosphate (or flavin mononucleotide, FMN) generates reactive oxygen species (ROS) upon photo-irradiation. FMN is required by all flavoproteins because it is a cofactor of biological blue-light receptors. The photochemical effects of FMN after irradiation by blue or violet light on the inactivation of Staphylococcus aureus strains, including a methicillin-resistant strain (MRSA), were investigated in this study. Upon blue- or violet-light photo-treatment, FMN was shown to inactivate S. aureus due to the generated ROS. Effective bacterial inactivation can be achieved by FMN photolysis without an exogenous electron provider. Inactivation rates of 94.9 and 95.2% in S. aureus and MRSA, respectively, can be reached by blue light irradiation (2.0mW/cm 2 ) with 120μM FMN for 120min. A lower FMN concentration and a shorter time are required to reach similar effects by violet light irradiation. Inactivation rates of 96.3 and 97.0% in S. aureus and MRSA, respectively, can be reached by violet light irradiation (1.0mW/cm 2 ) with 30μM FMN for 30min. The sensitivity of the inherent photosensitizers is lower under blue-light irradiation. A long exposure photolytic treatment of FMN by blue light is required to inactivate S. aureus. Violet light was found to be more efficient in S. aureus inactivation at the same radiant intensity. FMN photolysis with blue or violet light irradiation enhanced the inactivation rates of S. aureus and MRSA. FMN photochemical treatment could be a supplemental technique in hygienic decontamination processes. Copyright © 2017 Elsevier B.V. All rights reserved.

Apc inactivation, but not obesity, synergizes with Pten deficiency to drive intestinal stem cell-derived tumorigenesis.

Science.gov (United States)

Tabrizian, Tahmineh; Wang, Donghai; Guan, Fangxia; Hu, Zunju; Beck, Amanda P; Delahaye, Fabien; Huffman, Derek M

2017-06-01

Obesity is a major risk factor for colorectal cancer and can accelerate Lgr5+ intestinal stem cell (ISC)-derived tumorigenesis after the inactivation of Apc However, whether non-canonical pathways involving PI3K-Akt signaling in ISCs can lead to tumor formation, and if this can be further exacerbated by obesity is unknown. Despite the synergy between Pten and Apc inactivation in epithelial cells on intestinal tumor formation, their combined role in Lgr5+-ISCs, which are the most rapidly dividing ISC population in the intestine, is unknown. Lgr5+-GFP mice were provided low-fat diet (LFD) or high-fat diet (HFD) for 8 months, and the transcriptome was evaluated in Lgr5+-ISCs. For tumor studies, Lgr5+-GFP and Lgr5+-GFP- Pten flox/flox mice were tamoxifen treated to inactivate Pten in ISCs and provided LFD or HFD until 14-15 months of age. Finally, various combinations of Lgr5+-ISC-specific, Apc- and Pten -deleted mice were generated and evaluated for histopathology and survival. HFD did not overtly alter Akt signaling in ISCs, but did increase other metabolic pathways. Pten deficiency, but not HFD, increased BrdU-positive cells in the small intestine ( P  Apc deficiency synergistically increased proliferative markers, tumor pathology and mortality, in a dose-dependent fashion ( P  Apc deficiency in ISCs synergistically increases proliferation, tumor formation and mortality. Thus, aberrant Wnt/β-catenin, rather than PI3K-Akt signaling, is requisite for obesity to drive Lgr5+ ISC-derived tumorigenesis. © 2017 Society for Endocrinology.

Prospects for a novel ultrashort pulsed laser technology for pathogen inactivation

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Tsen Shaw-Wei D

2012-07-01

Full Text Available Abstract The threat of emerging pathogens and microbial drug resistance has spurred tremendous efforts to develop new and more effective antimicrobial strategies. Recently, a novel ultrashort pulsed (USP laser technology has been developed that enables efficient and chemical-free inactivation of a wide spectrum of viral and bacterial pathogens. Such a technology circumvents the need to introduce potentially toxic chemicals and could permit safe and environmentally friendly pathogen reduction, with a multitude of possible applications including the sterilization of pharmaceuticals and blood products, and the generation of attenuated or inactivated vaccines.

Inactivation of bacteria by electric current in the presence of carbon nanotubes embedded within a polymeric membrane.

Science.gov (United States)

Zhu, Anna; Liu, Harris K; Long, Feng; Su, Erzheng; Klibanov, Alexander M

2015-01-01

Uniform conductive composite membranes were prepared using a phase inversion method by blending carboxyl-functionalized multi-walled carbon nanotubes (CNTs) with a polysulfone polymer. At 6 % of the embedded CNTs, the membrane pore size measured by transmission electron microscopy (TEM) was approximately 50 nm. Electric current in the presence of the composite membranes markedly inactivated the model pathogenic bacteria Escherichia coli and Staphylococcus aureus, with the extent of bacterial inactivation rising when the current was increased. Over 99.999 % inactivation of both bacteria was observed in deionized water after 40 min at 5 mA direct current (DC); importantly, no appreciable inactivation occurred in the absence of either the electric field or the CNTs within the membranes under otherwise the same conditions. A much lower, although still pronounced, inactivation was seen with alternating current (AC) in a 25 mM NaCl aqueous solution.

Characterization of X chromosome inactivation using integrated analysis of whole-exome and mRNA sequencing.

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Szabolcs Szelinger

Full Text Available In females, X chromosome inactivation (XCI is an epigenetic, gene dosage compensatory mechanism by inactivation of one copy of X in cells. Random XCI of one of the parental chromosomes results in an approximately equal proportion of cells expressing alleles from either the maternally or paternally inherited active X, and is defined by the XCI ratio. Skewed XCI ratio is suggestive of non-random inactivation, which can play an important role in X-linked genetic conditions. Current methods rely on indirect, semi-quantitative DNA methylation-based assay to estimate XCI ratio. Here we report a direct approach to estimate XCI ratio by integrated, family-trio based whole-exome and mRNA sequencing using phase-by-transmission of alleles coupled with allele-specific expression analysis. We applied this method to in silico data and to a clinical patient with mild cognitive impairment but no clear diagnosis or understanding molecular mechanism underlying the phenotype. Simulation showed that phased and unphased heterozygous allele expression can be used to estimate XCI ratio. Segregation analysis of the patient's exome uncovered a de novo, interstitial, 1.7 Mb deletion on Xp22.31 that originated on the paternally inherited X and previously been associated with heterogeneous, neurological phenotype. Phased, allelic expression data suggested an 83∶20 moderately skewed XCI that favored the expression of the maternally inherited, cytogenetically normal X and suggested that the deleterious affect of the de novo event on the paternal copy may be offset by skewed XCI that favors expression of the wild-type X. This study shows the utility of integrated sequencing approach in XCI ratio estimation.

High pressure processing inactivates human norovirus within oysters

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Consumption of raw bivalve mollusks can result in norovirus infection. One potential intervention for virus-contaminated shellfish is high pressure processing (HPP). Currently HPP is known to inactivate Vibrio bacteria, hepatitis A virus, and murine norovirus within oysters. To evaluate the potentia...

Decreased prothrombin conversion and reduced thrombin inactivation explain rebalanced thrombin generation in liver cirrhosis.

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Romy M W Kremers

Full Text Available Impaired coagulation factor synthesis in cirrhosis causes a reduction of most pro- and anticoagulant factors. Cirrhosis patients show no clear bleeding or thrombotic phenotype, although they are at risk for both types of hemostatic event. Thrombin generation (TG is a global coagulation test and its outcome depends on underlying pro- and anticoagulant processes (prothrombin conversion and thrombin inactivation. We quantified the prothrombin conversion and thrombin inactivation during TG in 30 healthy subjects and 52 Child-Pugh (CP- A, 15 CP-B and 6 CP-C cirrhosis patients to test the hypothesis that coagulation is rebalanced in liver cirrhosis patients. Both prothrombin conversion and thrombin inactivation are reduced in cirrhosis patients. The effect on pro- and anticoagulant processes partially cancel each other out and as a result TG is comparable at 5 pM tissue factor between healthy subjects and patients. This supports the hypothesis of rebalanced hemostasis, as TG in cirrhosis patients remains within the normal range, despite large changes in prothrombin conversion and thrombin inactivation. Nevertheless, in silico analysis shows that normalization of either prothrombin conversion or thrombin inactivation to physiological levels, by for example the administration of prothrombin complex concentrates would cause an elevation of TG, whereas the normalization of both simultaneously maintains a balanced TG. Therefore, cirrhosis patients might require adapted hemostatic treatment.

Difunctional bacteriophage conjugated with photosensitizers for Candida albicans-targeting photodynamic inactivation.

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Dong, Shuai; Shi, Hongxi; Zhang, Xintong; Chen, Xi; Cao, Donghui; Mao, Chuanbin; Gao, Xiang; Wang, Li

2018-01-01

Candida albicans is the most prevalent fungal pathogen of the human microbiota, causing infections ranging from superficial infections of the skin to life-threatening systemic infections. Due to the increasing occurrence of antibiotic-resistant C. albicans strains, new approaches to control this pathogen are needed. Photodynamic inactivation is an emerging alternative to treat infections based on the interactions between visible light and photosensitisers, in which pheophorbide a (PPA) is a chlorophyll-based photosensitizer that could induce cell death after light irradiation. Due to PPA's phototoxicity and low efficiency, the main challenge is to implement photosensitizer cell targeting and attacking. In this study, PPA was conjugated with JM-phage by EDC/NHS crosslinking. UV-Vis spectra was used to determine the optimum conjugation percentages of PPA and JM-phage complex for photodynamic inactivation. After photodynamic inactivation, the efficacy of PPA-JM-phage was assessed by performing in vitro experiments, such as MTS assay, scanning electron microscopy, measurement of dysfunctional mitochondria, ROS accumulation, S cell arrest and apoptotic pathway. A single-chain variable-fragment phage (JM) with high affinity to MP65 was screened from human single-fold single-chain variable-fragment libraries and designed as a binding target for C. albicans cells. Subsequently, PPa was integrated into JM phage to generate a combined nanoscale material, which was called PPA-JM-phage. After photodynamic inactivation, the growth of C. albicans was inhibited by PPA-JM-phage and apoptosis was observed. Scanning electron microscopy analysis revealed shrinking and rupturing of C. albicans . We also found that depolarization of mitochondrial membrane potential was decreased and intracellular reactive oxygen species levels were elevated significantly in C. albicans inhibited by PPA-JM-phage. Additionally, PPA-JM-phage also lead to S-phase arrest, and metacaspase activation

Ultraviolet-C irradiation for inactivation of viruses in foetal bovine serum.

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Vaidya, Vivek; Dhere, Rajeev; Agnihotri, Snehal; Muley, Ravindra; Patil, Sanjay; Pawar, Amit

2018-07-05

Foetal Bovine Serum (FBS) and porcine trypsin are one of the essential raw materials used in the manufacturing of cell culture based viral vaccines. Being from animal origin, these raw materials can potentially contaminate the final product by known or unknown adventitious agents. The issue is more serious in case of live attenuated viral vaccines, where there is no inactivation step which can take care of such adventitious agents. It is essential to design production processes which can offer maximum viral clearance potential for animal origin products. Ultraviolet-C irradiation is known to inactivate various adventitious viral agents; however there are limited studies on ultraviolet inactivation of viruses in liquid media. We obtained a recently developed UVivatec ultraviolet-C (UV-C) irradiation based viral clearance system for evaluating its efficacy to inactivate selected model viruses. This system has a unique design with spiral path of liquid allowing maximum exposure to UV-C light of a short wavelength of 254 nm. Five live attenuated vaccine viruses and four other model viruses were spiked in tissue culture media and exposed to UV-C irradiation. The pre and post UV-C irradiation samples were analyzed for virus content to find out the extent of inactivation of various viruses. These experiments showed substantial log reduction for the majority of the viruses with few exceptions based on the characteristics of these viruses. Having known the effect of UV irradiation on protein structure, we also evaluated the post irradiation samples of culture media for growth promoting properties using one of the most fastidious human diploid cells (MRC-5). UV-C exposure did not show any notable impact on the nutritional properties of culture media. The use of an UV-C irradiation based system is considered to be promising approach to mitigate the risk of adventitious agents in cell culture media arising through animal derived products. Copyright © 2018 Elsevier Ltd. All

Photodynamic inactivation of pathogens causing infectious keratitis

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Simon, Carole; Wolf, G.; Walther, M.; Winkler, K.; Finke, M.; Hüttenberger, D.; Bischoff, Markus; Seitz, B.; Cullum, J.; Foth, H.-J.

2014-03-01

The increasing prevalence of antibiotic resistance requires new approaches also for the treatment of infectious keratitis. Photodynamic Inactivation (PDI) using the photosensitizer (PS) Chlorin e6 (Ce6) was investigated as an alternative to antibiotic treatment. An in-vitro cornea model was established using porcine eyes. The uptake of Ce6 by bacteria and the diffusion of the PS in the individual layers of corneal tissue were investigated by fluorescence. After removal of the cornea's epithelium Ce6-concentrations tested in liquid culture against different concentrations of Ce6 (1 - 512 μM) using 10 minutes irradiation (E = 18 J/cm2 ). This demonstrated that a complete inactivation of the pathogen strains were feasible whereby SA was slightly more susceptible than PA. 3909 mutants of the Keio collection of Escherichia coli (E.coli) were screened for potential resistance factors. The sensitive mutants can be grouped into three categories: transport mutants, mutants in lipopolysaccharide synthesis and mutants in the bacterial SOS-response. In conclusion PDI is seen as a promising therapy concept for infectious keratitis.

Influvac, a trivalent inactivated subunit influenza vaccine.

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Zuccotti, Gian Vincenzo; Fabiano, Valentina

2011-01-01

Influenza represents a major sanitary and socio-economic burden and vaccination is universally considered the most effective strategy for preventing the disease and its complications. Traditional influenza vaccines have been on the market since the late 1940s, with million of doses administered annually worldwide, and demonstrated a substantial efficacy and safety. The trivalent inactivated subunit vaccine has been available for more than 25 years and has been studied in healthy children, adults and the elderly and in people affected by underlying chronic medical conditions. We describe vaccine technology focusing on subunit vaccine production procedures and mode of action and provide updated information on efficacy and safety available data. A review of efficacy and safety data in healthy subjects and in high risk populations from major sponsor- and investigator-driven studies. The vaccine showed a good immunogenicity and a favorable safety profile in all target groups. In the panorama of actually available influenza vaccines, trivalent inactivated subunit vaccine represents a well-established tool for preventing flu and the associated complications.

Field and laboratory investigations of inactivation of viruses (PRD1 and MS2) attached to iron oxide-coated quartz san

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Ryan, Joseph N.; Harvey, Ronald W.; Metge, David W.; Elimelech, Menachem; Navigato, Theresa; Pieper, Ann P.

2002-01-01

Field and laboratory experiments were conducted to investigate inactivation of viruses attached to mineral surfaces. In a natural gradient transport field experiment, bacteriophage PRD1, radiolabeled with 32P, was injected into a ferric oxyhydroxide-coated sand aquifer with bromide and linear alkylbenzene sulfonates. In a zone of the aquifer contaminated by secondary sewage infiltration, small fractions of infective and 32P-labeled PRD1 broke through with the bromide tracer, followed by the slow release of 84% of the 32P activity and only 0.011% of the infective PRD1. In the laboratory experiments, the inactivation of PRD1, labeled with 35S (protein capsid), and MS2, dual radiolabeled with 35S (protein capsid) and 32P (nucleic acid), was monitored in the presence of groundwater and sediment from the contaminated zone of the field site. Release of infective viruses decreased at a much faster rate than release of the radiolabels, indicating that attached viruses were undergoing surface inactivation. Disparities between 32P and35S release suggest that the inactivated viruses were released in a disintegrated state. Comparison of estimated solution and surface inactivation rates indicates solution inactivation is ∼3 times as fast as surface inactivation. The actual rate of surface inactivation may be substantially underestimated owing to slow release of inactivated viruses.

Heavy ion effects on mammalian cells: Inactivation measurements with different cell lines

International Nuclear Information System (INIS)

Wulf, H.; Kraft-Weyrather, W.; Miltenburger, H.G.; Kraft, G.

1985-07-01

In track segment experiments, the inactivation of different mammalian cells by heavy charged particles between helium and uranium in the energy range between 1 and 1000 MeV/u has been measured at the heavy ion accelerator Unilac, Darmstadt, the Tandem Van de Graaf, Heidelberg and the Bevalac, Berkeley. The inactivation cross sections calculated from the final slope of the dose effect curves are given as a function of the particle energy and the LET. (orig.)

Non-thermal plasma-activated water inactivation of food-borne pathogen on fresh produce

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Ma, Ruonan; Wang, Guomin; Tian, Ying; Wang, Kaile [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zhang, Jue, E-mail: zhangjue@pku.edu.cn [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China); Fang, Jing [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China)

2015-12-30

Highlights: • We propose a new approach to treat S. aureus inoculated on strawberries by PAW. • PAW could inactivate S. aureus on strawberries via the Log Reduction results, further confirmed by CLSM and SEM. • The short-lived ROS in PAW are considered the most important agents in inactivation process. • No significant change was found in color, firmness and pH of the PAW treated strawberries. - Abstract: Non-thermal plasma has been widely considered to be an effective method for decontamination of foods. Recently, numerous studies report that plasma-activated water (PAW) also has outstanding antibacterial ability. This study presents the first report on the potential of PAW for the inactivation of Staphylococcus aureus (S. aureus) inoculated on strawberries. PAW treatments achieved a reduction of S. aureus ranging from 1.6 to 2.3 log at day-0 storage, while 1.7 to 3.4 log at day-4 storage. The inactivation efficiency depended on the plasma-activated time for PAW generation and PAW-treated time of strawberries inoculated with S. aureus. LIVE/DEAD staining and scanning electron microscopy results confirm that PAW could damage the bacterial cell wall. Moreover, optical emission spectra and oxidation reduction potential results demonstrate the inactivation is mainly attributed to oxidative stress induced by reactive oxygen species in PAW. In addition, no significant change was found in color, firmness and pH of the PAW treated strawberries. Thus, PAW can be a promising alternative to traditional sanitizers applied in the fresh produce industry.

Non-thermal plasma-activated water inactivation of food-borne pathogen on fresh produce

International Nuclear Information System (INIS)

Ma, Ruonan; Wang, Guomin; Tian, Ying; Wang, Kaile; Zhang, Jue; Fang, Jing

2015-01-01

Highlights: • We propose a new approach to treat S. aureus inoculated on strawberries by PAW. • PAW could inactivate S. aureus on strawberries via the Log Reduction results, further confirmed by CLSM and SEM. • The short-lived ROS in PAW are considered the most important agents in inactivation process. • No significant change was found in color, firmness and pH of the PAW treated strawberries. - Abstract: Non-thermal plasma has been widely considered to be an effective method for decontamination of foods. Recently, numerous studies report that plasma-activated water (PAW) also has outstanding antibacterial ability. This study presents the first report on the potential of PAW for the inactivation of Staphylococcus aureus (S. aureus) inoculated on strawberries. PAW treatments achieved a reduction of S. aureus ranging from 1.6 to 2.3 log at day-0 storage, while 1.7 to 3.4 log at day-4 storage. The inactivation efficiency depended on the plasma-activated time for PAW generation and PAW-treated time of strawberries inoculated with S. aureus. LIVE/DEAD staining and scanning electron microscopy results confirm that PAW could damage the bacterial cell wall. Moreover, optical emission spectra and oxidation reduction potential results demonstrate the inactivation is mainly attributed to oxidative stress induced by reactive oxygen species in PAW. In addition, no significant change was found in color, firmness and pH of the PAW treated strawberries. Thus, PAW can be a promising alternative to traditional sanitizers applied in the fresh produce industry.

Glucose oxidase stabilization against thermal inactivation using high hydrostatic pressure and hydrophobic modification.

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Halalipour, Ali; Duff, Michael R; Howell, Elizabeth E; Reyes-De-Corcuera, José I

2017-03-01

High hydrostatic pressure (HHP) stabilized glucose oxidase (GOx) against thermal inactivation. The apparent first-order kinetics of inactivation of GOx were investigated at 0.1-300 MPa and 58.8-80.0°C. At 240 MPa and 74.5°C, GOx inactivated at a rate 50 times slower than at atmospheric pressure at the same temperature. The apparent activation energy of inactivation at 300 MPa was 281.0 ± 17.4 kJ mol -1 or 1.3-fold smaller than for the inactivation at atmospheric pressure (378.1 ± 25.6 kJ mol -1 ). The stabilizing effect of HHP was greatest at 74.5°C, where the activation volume of 57.0 ± 12.0 cm 3  mol -1 was highest compared to all other studied temperatures. Positive apparent activation volumes for all the treatment temperatures confirmed that HHP favors GOx stabilization. A second approach to increase GOx stability involved crosslinking with N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and either aniline or benzoate. The modified enzyme remained fully active with only slight increases in K M (1.3-1.9-fold increases for aniline and benzoate modification, respectively). The thermal stability of GOx increased by 8°C with aniline modification, while it decreased by 0.9°C upon modification with benzoate. Biotechnol. Bioeng. 2017;114: 516-525. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

The inactivation of human CYP2E1 by phenethyl isothiocyanate, a naturally occurring chemopreventive agent, and its oxidative bioactivation.

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Yoshigae, Yasushi; Sridar, Chitra; Kent, Ute M; Hollenberg, Paul F

2013-04-01

Phenethylisothiocyanate (PEITC), a naturally occurring isothiocyanate and potent cancer chemopreventive agent, works by multiple mechanisms, including the inhibition of cytochrome P450 (P450) enzymes, such as CYP2E1, that are involved in the bioactivation of carcinogens. PEITC has been reported to be a mechanism-based inactivator of some P450s. We describe here the possible mechanism for the inactivation of human CYP2E1 by PEITC, as well as the putative intermediate that might be involved in the bioactivation of PEITC. PEITC inactivated recombinant CYP2E1 with a partition ratio of 12, and the inactivation was not inhibited in the presence of glutathione (GSH) and not fully recovered by dialysis. The inactivation of CYP2E1 by PEITC is due to both heme destruction and protein modification, with the latter being the major pathway for inactivation. GSH-adducts of phenethyl isocyanate (PIC) and phenethylamine were detected during the metabolism by CYP2E1, indicating formation of PIC as a reactive intermediate following P450-catalyzed desulfurization of PEITC. Surprisingly, PIC bound covalently to CYP2E1 to form protein adducts but did not inactivate the enzyme. Liquid chromatography mass spectroscopy analysis of the inactivated CYP2E1 apo-protein suggests that a reactive sulfur atom generated during desulfurization of PEITC is involved in the inactivation of CYP2E1. Our data suggest that the metabolism of PEITC by CYP2E1 that results in the inactivation of CYP2E1 may occur by a mechanism similar to that observed with other sulfur-containing compounds, such as parathion. Digestion of the inactivated enzyme and analysis by SEQUEST showed that Cys 268 may be the residue modified by PIC.

Immunomodulatory effect of non-viable components of probiotic culture stimulated with heat-inactivated Escherichia coli and Bacillus cereus on holoxenic mice.

Science.gov (United States)

Ditu, L M; Chifiriuc, M C; Bezirtzoglou, E; Marutescu, L; Bleotu, C; Pelinescu, D; Mihaescu, G; Lazar, V

2014-01-01

Competition of probiotic bacteria with other species from the intestinal microbiota involves different mechanisms that occur regardless of probiotics' viability. The objective of this paper was to assess the cytokine serum levels in holoxenic mice after oral administration of non-viable components (NVC) of Enterococcus faecium probiotic culture stimulated with heat-inactivated Escherichia coli and Bacillus cereus in comparison to NVC of unstimulated E. faecium probiotic culture. Probiotic E. faecium CMGb 16 culture, grown in the presence of heat-inactivated cultures of E. coli and B. cereus CMGB 102, was subsequently separated into supernatant (SN) and heat-inactivated cellular sediment (CS) fractions by centrifugation. Each NVC was orally administered to holoxenic mice (balb C mouse strain), in three doses, given at 24 hours. Blood samples were collected from the retinal artery, at 7, 14, and 21 days after the first administration of the NVC. The serum concentrations of IL-12 and tumor necrosis factor-alpha (TNF-α) interleukins were assessed by ELISA method. After the oral administration of SN component obtained from the probiotic culture stimulated with heat-inactivated cultures of B. cereus CMGB 102 and E. coli O28, the serum concentrations of IL-12 were maintained higher in the samples collected at 7 and 14 days post-administration. No specific TNF-α profile could be established, depending on stimulated or non-stimulated probiotic culture, NVC fraction, or harvesting time. The obtained results demonstrate that non-viable fractions of probiotic bacteria, stimulated by other bacterial species, could induce immunostimulatory effects mediated by cytokines and act, therefore, as immunological adjuvants.

Mechanism of Bacillus subtilis spore inactivation by and resistance to supercritical CO2 plus peracetic acid.

Science.gov (United States)

Setlow, B; Korza, G; Blatt, K M S; Fey, J P; Setlow, P

2016-01-01

Determine how supercritical CO2 (scCO2 ) plus peracetic acid (PAA) inactivates Bacillus subtilis spores, factors important in spore resistance to scCO2 -PAA, and if spores inactivated by scCO2 -PAA are truly dead. Spores of wild-type B. subtilis and isogenic mutants lacking spore protective proteins were treated with scCO2 -PAA in liquid or dry at 35°C. Wild-type wet spores (aqueous suspension) were more susceptible than dry spores. Treated spores were examined for viability (and were truly dead), dipicolinic acid (DPA), mutations, permeability to nucleic acid stains, germination under different conditions, energy metabolism and outgrowth. ScCO2 -PAA-inactivated spores retained DPA, and survivors had no notable DNA damage. However, DPA was released from inactivated spores at a normally innocuous temperature (85°C), and colony formation from treated spores was salt sensitive. The inactivated spores germinated but did not outgrow, and these germinated spores had altered plasma membrane permeability and defective energy metabolism. Wet or dry coat-defective spores had increased scCO2 -PAA sensitivity, and dry spores but not wet spores lacking DNA protective proteins were more scCO2 -PAA sensitive. These findings suggest that scCO2 -PAA inactivates spores by damaging spores' inner membrane. The spore coat provided scCO2 -PAA resistance for both wet and dry spores. DNA protective proteins provided scCO2 -PAA resistance only for dry spores. These results provide information on mechanisms of spore inactivation of and resistance to scCO2 -PAA, an agent with increasing use in sterilization applications. © 2015 The Society for Applied Microbiology.

Inactivation of viable Ascaris eggs by reagents during enumeration.

Science.gov (United States)

Nelson, K L; Darby, J L

2001-12-01

Various reagents commonly used to enumerate viable helminth eggs from wastewater and sludge were evaluated for their potential to inactivate Ascaris eggs under typical laboratory conditions. Two methods were used to enumerate indigenous Ascaris eggs from sludge samples. All steps in the methods were the same except that in method I a phase extraction step with acid-alcohol (35% ethanol in 0.1 N H(2)SO(4)) and diethyl ether was used whereas in method II the extraction step was avoided by pouring the sample through a 38-microm-mesh stainless steel sieve that retained the eggs. The concentration of eggs and their viability were lower in the samples processed by method I than in the samples processed by method II by an average of 48 and 70%, respectively. A second set of experiments was performed using pure solutions of Ascaris suum eggs to elucidate the effect of the individual reagents and relevant combination of reagents on the eggs. The percentages of viable eggs in samples treated with acid-alcohol alone and in combination with diethyl ether or ethyl acetate were 52, 27, and 4%, respectively, whereas in the rest of the samples the viability was about 80%. Neither the acid nor the diethyl ether alone caused any decrease in egg viability. Thus, the observed inactivation was attributed primarily to the 35% ethanol content of the acid-alcohol solution. Inactivation of the eggs was prevented by limiting the direct exposure to the extraction reagents to 30 min and diluting the residual concentration of acid-alcohol in the sample by a factor of 100 before incubation. Also, the viability of the eggs was maintained if the acid-alcohol solution was replaced with an acetoacetic buffer. None of the reagents used for the flotation step of the sample cleaning procedure (ZnSO(4), MgSO(4), and NaCl) or during incubation (0.1 N H(2)SO(4) and 0.5% formalin) inactivated the Ascaris eggs under the conditions studied.

Inactivation of Prions and Amyloid Seeds with Hypochlorous Acid.

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Andrew G Hughson

2016-09-01

Full Text Available Hypochlorous acid (HOCl is produced naturally by neutrophils and other cells to kill conventional microbes in vivo. Synthetic preparations containing HOCl can also be effective as microbial disinfectants. Here we have tested whether HOCl can also inactivate prions and other self-propagating protein amyloid seeds. Prions are deadly pathogens that are notoriously difficult to inactivate, and standard microbial disinfection protocols are often inadequate. Recommended treatments for prion decontamination include strongly basic (pH ≥~12 sodium hypochlorite bleach, ≥1 N sodium hydroxide, and/or prolonged autoclaving. These treatments are damaging and/or unsuitable for many clinical, agricultural and environmental applications. We have tested the anti-prion activity of a weakly acidic aqueous formulation of HOCl (BrioHOCl that poses no apparent hazard to either users or many surfaces. For example, BrioHOCl can be applied directly to skin and mucous membranes and has been aerosolized to treat entire rooms without apparent deleterious effects. Here, we demonstrate that immersion in BrioHOCl can inactivate not only a range of target microbes, including spores of Bacillus subtilis, but also prions in tissue suspensions and on stainless steel. Real-time quaking-induced conversion (RT-QuIC assays showed that BrioHOCl treatments eliminated all detectable prion seeding activity of human Creutzfeldt-Jakob disease, bovine spongiform encephalopathy, cervine chronic wasting disease, sheep scrapie and hamster scrapie; these findings indicated reductions of ≥103- to 106-fold. Transgenic mouse bioassays showed that all detectable hamster-adapted scrapie infectivity in brain homogenates or on steel wires was eliminated, representing reductions of ≥~105.75-fold and >104-fold, respectively. Inactivation of RT-QuIC seeding activity correlated with free chlorine concentration and higher order aggregation or destruction of proteins generally, including prion

Two-Dimensional Microdischarge Jet Array in Air: Characterization and Inactivation of Virus

Science.gov (United States)

Nayak, Gaurav

OES to measure the O2(a 1Deltag) density and spectrophotometry to estimate the NOx species density in aqueous medium. The results show that the discharge activity is strongly dependent on the gas flow rate particularly for gas residence times comparable to the applied high voltage cycle. The maximum difference in gas temperature at extreme plasma conditions do not exceed 50 K. The NO density is found to be reducing with smaller gas residence time. It is found that the reduced field E/N is dependent on the flow rate. The observed variation in the electric field is attributed to the change in the neutral gas densities. Both gas residence time and humidity have an impact on the space-charge distribution. The O 3 density is found to increase with increasing power density and saturates at higher power above 12 W, and the maximum density of 1022 m-3 is achieved at an intermediate flow rate of 20 slm. An optimal condition for O2(a 1Deltag) generation is found that is a balance between power and gas residence. Higher specific energy leads to higher increase of O2(a 1Deltag) density as compared to the O3 density. It is also observed that the O2(a 1Deltag) to O3 density ratio could be controlled by the flow rate from 0.7 to almost 0. The discharge source is used for FCV inactivation on surfaces (in the gas phase) and suspended in solution. Discharge power and treatment time have strong effect on the reduction in virus titer, while exposure distance or flow rate have negligible effect. Humidity plays a major effect on FCV inactivation on surfaces, leading to complete inactivation (>4 log10) within 3 minutes of treatment. FCV inactivation can be explained by O3 in gas phase and RNS in liquid phase. Nonetheless synergistic effects of ROS and RNS cannot be excluded, as similar production rates of O3 and NOx in discharge are determined. The O2(a 1Deltag) density at conditions used for FCV treatment is at least 2 orders of magnitude lower than the ozone density and is not a dominant

[Mechanism of action of neurotoxins acting on the inactivation of voltage-gated sodium channels].

Science.gov (United States)

Benoit, E

1998-01-01

This review focuses on the mechanism(s) of action of neurotoxins acting on the inactivation of voltage-gated Na channels. Na channels are transmembrane proteins which are fundamental for cellular communication. These proteins form pores in the plasma membrane allowing passive ionic movements to occur. Their opening and closing are controlled by gating systems which depend on both membrane potential and time. Na channels have three functional properties, mainly studied using electrophysiological and biochemical techniques, to ensure their role in the generation and propagation of action potentials: 1) a highly selectivity for Na ions, 2) a rapid opening ("activation"), responsible for the depolarizing phase of the action potential, and 3) a late closing ("inactivation") involved in the repolarizing phase of the action potential. As an essential protein for membrane excitability, the Na channel is the specific target of a number of vegetal and animal toxins which, by binding to the channel, alter its activity by affecting one or more of its properties. At least six toxin receptor sites have been identified on the neuronal Na channel on the basis of binding studies. However, only toxins interacting with four of these sites (sites 2, 3, 5 et 6) produce alterations of channel inactivation. The maximal percentage of Na channels modified by the binding of neurotoxins to sites 2 (batrachotoxin and some alkaloids), 3 (alpha-scorpion and sea anemone toxins), 5 (brevetoxins and ciguatoxins) et 6 (delta-conotoxins) is different according to the site considered. However, in all cases, these channels do not inactivate. Moreover, Na channels modified by toxins which bind to sites 2, 5 and 6 activate at membrane potentials more negative than do unmodified channels. The physiological consequences of Na channel modifications, induced by the binding of neurotoxins to sites 2, 3, 5 and 6, are (i) an inhibition of cellular excitability due to an important membrane depolarization (site

Proteomic analysis reveals a novel function of the kinase Sat4p in Saccharomyces cerevisiae mitochondria.

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Uta Gey

Full Text Available The Saccharomyces cerevisiae kinase Sat4p has been originally identified as a protein involved in salt tolerance and stabilization of plasma membrane transporters, implicating a cytoplasmic localization. Our study revealed an additional mitochondrial (mt localization, suggesting a dual function for Sat4p. While no mt related phenotype was observed in the absence of Sat4p, its overexpression resulted in significant changes of a specific mitochondrial subproteome. As shown by a comparative two dimensional difference gel electrophoresis (2D-DIGE approach combined with mass spectrometry, particularly two groups of proteins were affected: the iron-sulfur containing aconitase-type proteins (Aco1p, Lys4p and the lipoamide-containing subproteome (Lat1p, Kgd2p and Gcv3p. The lipoylation sites of all three proteins could be assigned by nanoLC-MS/MS to Lys75 (Lat1p, Lys114 (Kgd2p and Lys102 (Gcv3p, respectively. Sat4p overexpression resulted in accumulation of the delipoylated protein variants and in reduced levels of aconitase-type proteins, accompanied by a decrease in the activities of the respective enzyme complexes. We propose a regulatory role of Sat4p in the late steps of the maturation of a specific subset of mitochondrial iron-sulfur cluster proteins, including Aco1p and lipoate synthase Lip5p. Impairment of the latter enzyme may account for the observed lipoylation defects.

The inhibitory effect of convulsant agents on the enzyme in brain which inactivates nerveside.

Science.gov (United States)

Toh, C C

1969-07-01

1. An enzyme which can be extracted from brain inactivates nerveside in the optimum pH range 5.8-7.0.2. The polybasic acids trypan blue and its analogue trypan red, bromphenol blue and its analogue bromthymol blue at concentrations of 0.22 mM and ethylenediaminetetra-acetic acid (EDTA) at a concentration of 1 mM are strong inhibitors of the enzyme.3. Penicillin which is a monobasic carboxylic acid also inhibits the enzyme but only if concentrations as high as 3.6 mM are used. The antibiotic streptomycin which is a basic substance does not inhibit the enzyme.4. Caffeine at a concentration of 7.2 mM only weakly inhibits the enzyme.5. Chymotrypsin and wheat germ acid phosphatase also inactivate nerveside at pH 5.9 and are inhibited by the acidic dyes and penicillin. EDTA inhibits wheat germ phosphatase but activates chymotrypsin.6. Inactivation of nerveside by the brain enzyme and by wheat germ phosphatase is different from the action of chymotrypsin. Nerveside solutions incubated with chymotrypsin completely lose all biological activity whereas if incubation is carried out with either the brain enzyme or wheat germ acid phosphatase a residual biological activity remains even when the concentration of these two enzymes is increased. This residual biological activity is due to a peptide as it is destroyed by chymotrypsin.7. The manner in which nerveside is inactivated by the brain enzyme is uncertain as the preparation of the latter contained phosphodiesterase and protease activities which were similarly inhibited by the acid dyes, penicillin and EDTA.8. Pentylenetetrazole, picrotoxin, strychnine and tetanus toxin do not inhibit the brain enzyme.9. The nerveside-inactivating enzyme is not identical with the Substance P-inactivating enzyme in brain as the former is inhibited by EDTA while the latter is not.

Water treatment with exceptional virus inactivation using activated carbon modified with silver (Ag) and copper oxide (CuO) nanoparticles.

Science.gov (United States)

Shimabuku, Quelen Letícia; Arakawa, Flávia Sayuri; Fernandes Silva, Marcela; Ferri Coldebella, Priscila; Ueda-Nakamura, Tânia; Fagundes-Klen, Márcia Regina; Bergamasco, Rosangela

2017-08-01

Continuous flow experiments (450 mL min -1 ) were performed in household filter in order to investigate the removal and/or inactivation of T4 bacteriophage, using granular activated carbon (GAC) modified with silver and/or copper oxide nanoparticles at different concentrations. GAC and modified GAC were characterized by X-ray diffractometry, specific surface area, pore size and volume, pore average diameter, scanning electron microscopy, transmission electron microscopy, zeta potential and atomic absorption spectroscopy. The antiviral activity of the produced porous media was evaluated by passing suspensions of T4 bacteriophage (∼10 5  UFP/mL) through filters. The filtered water was analyzed for the presence of the bacteriophage and the release of silver and copper oxide. The porous media containing silver and copper oxide nanoparticles showed high inactivation capacity, even reaching reductions higher than 3 log. GAC6 (GAC/Ag0.5%Cu1.0%) was effective in the bacteriophage inactivation, reaching 5.53 log reduction. The levels of silver and copper released in filtered water were below the recommended limits (100 ppb for silver and 1000 ppb for copper) in drinking water. From this study, it is possible to conclude that activated carbon modified with silver and copper oxide nanoparticles can be used as a filter for virus removal in the treatment of drinking water.

“Redundancy” of Endocannabinoid Inactivation: New Challenges and Opportunities for Pain Control

Science.gov (United States)

2012-01-01

Redundancy of metabolic pathways and molecular targets is a typical feature of all lipid mediators, and endocannabinoids, which were originally defined as endogenous agonists at cannabinoid CB1 and CB2 receptors, are no exception. In particular, the two most studied endocannabinoids, anandamide and 2-arachidonoylglycerol, are inactivated through alternative biochemical routes, including hydrolysis and oxidation, and more than one enzyme might be used even for the same type of inactivating reaction. These enzymes also recognize as substrates other concurrent lipid mediators, whereas, in turn, endocannabinoids might interact with noncannabinoid receptors with subcellular distribution and ultimate biological actions either similar to or completely different from those of cannabinoid receptors. Even splicing variants of endocannabinoid hydrolyzing enzymes, such as FAAH-1, might play distinct roles in endocannabinoid inactivation. Finally, the products of endocannabinoid catabolism may have their own targets, with biological roles different from those of cannabinoid receptors. These peculiarities of endocannabinoid signaling have complicated the use of inhibitors of its inactivation mechanisms as a safer and more efficacious alternative to the direct targeting of cannabinoid receptors for the treatment of several pathological conditions, including pain. However, new strategies, including the rediscovery of “dirty drugs”, and the use of certain natural products (including non-THC cannabis constituents), are emerging that might allow us to make a virtue of necessity and exploit endocannabinoid redundancy to develop new analgesics. PMID:22860203

Use of genetic algorithms for high hydrostatic pressure inactivation ...

African Journals Online (AJOL)

) for high hydrostatic pressure (HHP) inactivation of Bacillus cereus spores, Bacillus subtilis spores and cells, Staphylococcus aureus and Listeria monocytogenes, all in milk buffer, were used to demonstrate the utility of genetic algorithms ...

Acute toxicity and inactivation tests of CO2 on invertebrates in drinking water treatment systems.

Science.gov (United States)

Yin, Wen-Chao; Zhang, Jin-Song; Liu, Li-Jun; Zhao, Jian-Shu; Li, Tuo

2011-01-01

In addition to the esthetic problem caused by invertebrates, researchers are recently starting to be more aware of their potential importance in terms of public health. However, the inactivation methods of invertebrates which could proliferate in drinking water treatment systems are not well developed. The objective of this study is to assess the acute toxicity and inactivation effects of CO2 on familiar invertebrates in water treatment processes. The results of this study revealed that CO2 has a definite toxicity to familiar invertebrates. The values of 24-h LC50 (median lethal concentration) were calculated for each test with six groups of invertebrates. The toxicity of CO2 was higher with increasing concentrations in solution but was lower with the increase in size of the invertebrates. Above the concentration of 1,000 mg/L for the CO2 solution, the 100% inactivation time of all the invertebrates was less than 5 s, and in 15 min, the inactivation ratio showed a gradient descent with a decline in concentration. As seen for Mesocyclops thermocyclopoides, by dosing with a sodium bicarbonate solution first and adding a dilute hydrochloric acid solution 5 min later, it is possible to obtain a satisfactory inactivation effect in the GAC (granular activated carbon) filters.

Inactivation of the maternal fragile X gene results in sensitization of GABAB receptor function in the offspring

OpenAIRE

Zupan, Bojana; Toth, Miklos

2008-01-01

Fragile X syndrome is an X linked disorder caused by the inactivation of the FMR-1 gene with symptoms ranging from impaired cognitive functions to seizures, anxiety, sensory abnormalities and hyperactivity. Although Fragile X syndrome is considered a typical Mendelian disorder, we have recently reported that the environment, specifically the fmr-1+/− or fmr-1−/− (H or KO) maternal environment, elicits on its own a partial fragile X-like phenotype and can contribute to the overall phenotype of...

Inactivation of 10(15) chimpanzee-infectious doses of hepatitis B virus during preparation of a heat-inactivated hepatitis B vaccine

NARCIS (Netherlands)

Lelie, P. N.; Reesink, H. W.; Niessen, J.; Brotman, B.; Prince, A. M.

1987-01-01

The safety of a plasma-derived hepatitis-B vaccine inactivated by two heating steps (90 sec at 103 degrees C followed by 10 hr pasteurization at 65 degrees C) was validated in chimpanzees; 10(3) chimpanzee-infectious doses (CID50) of hepatitis-B virus (HBV), subjected to the purification steps

Combination of microsecond and nanosecond pulsed electric field treatments for inactivation of Escherichia coli in water samples.

Science.gov (United States)

Žgalin, Maj Kobe; Hodžić, Duša; Reberšek, Matej; Kandušer, Maša

2012-10-01

Inactivation of microorganisms with pulsed electric fields is one of the nonthermal methods most commonly used in biotechnological applications such as liquid food pasteurization and water treatment. In this study, the effects of microsecond and nanosecond pulses on inactivation of Escherichia coli in distilled water were investigated. Bacterial colonies were counted on agar plates, and the count was expressed as colony-forming units per milliliter of bacterial suspension. Inactivation of bacterial cells was shown as the reduction of colony-forming units per milliliter of treated samples compared to untreated control. According to our results, when using microsecond pulses the level of inactivation increases with application of more intense electric field strengths and with number of pulses delivered. Almost 2-log reductions in bacterial counts were achieved at a field strength of 30 kV/cm with eight pulses and a 4.5-log reduction was observed at the same field strength using 48 pulses. Extending the duration of microsecond pulses from 100 to 250 μs showed no improvement in inactivation. Nanosecond pulses alone did not have any detectable effect on inactivation of E. coli regardless of the treatment time, but a significant 3-log reduction was achieved in combination with microsecond pulses.

Nondeterministic computational fluid dynamics modeling of Escherichia coli inactivation by peracetic acid in municipal wastewater contact tanks.

Science.gov (United States)

Santoro, Domenico; Crapulli, Ferdinando; Raisee, Mehrdad; Raspa, Giuseppe; Haas, Charles N

2015-06-16

Wastewater disinfection processes are typically designed according to heuristics derived from batch experiments in which the interaction among wastewater quality, reactor hydraulics, and inactivation kinetics is often neglected. In this paper, a computational fluid dynamics (CFD) study was conducted in a nondeterministic (ND) modeling framework to predict the Escherichia coli inactivation by peracetic acid (PAA) in municipal contact tanks fed by secondary settled wastewater effluent. The extent and variability associated with the observed inactivation kinetics were both satisfactorily predicted by the stochastic inactivation model at a 95% confidence level. Moreover, it was found that (a) the process variability induced by reactor hydraulics is negligible when compared to the one caused by inactivation kinetics, (b) the PAA dose required for meeting regulations is dictated equally by the fixed limit of the microbial concentration as well as its probability of occurrence, and (c) neglecting the probability of occurrence during process sizing could lead to an underestimation of the PAA dose required by as much as 100%. Finally, the ND-CFD model was used to generate sizing information in the form of probabilistic disinfection curves relating E. coli inactivation and probability of occurrence with the average PAA dose and PAA residual concentration at the outlet of the contact tank.

Study of the integrated immune response induced by an inactivated EV71 vaccine.

Directory of Open Access Journals (Sweden)

Longding Liu

Full Text Available Enterovirus 71 (EV71, a major causative agent of hand-foot-and-mouth disease (HFMD, causes outbreaks among children in the Asia-Pacific region. A vaccine is urgently needed. Based on successful pre-clinical work, phase I and II clinical trials of an inactivated EV71 vaccine, which included the participants of 288 and 660 respectively, have been conducted. In the present study, the immune response and the correlated modulation of gene expression in the peripheral blood mononuclear cells (PBMCs of 30 infants (6 to 11 months immunized with this vaccine or placebo and consented to join this study in the phase II clinical trial were analyzed. The results showed significantly greater neutralizing antibody and specific T cell responses in vaccine group after two inoculations on days 0 and 28. Additionally, more than 600 functional genes that were up- or down-regulated in PBMCs were identified by the microarray assay, and these genes included 68 genes associated with the immune response in vaccine group. These results emphasize the gene expression profile of the immune system in response to an inactivated EV71 vaccine in humans and confirmed that such an immune response was generated as the result of the positive mobilization of the immune system. Furthermore, the immune response was not accompanied by the development of a remarkable inflammatory response.NCT01391494 and NCT01512706.

Basolateral amygdala inactivation impairs learning-induced long-term potentiation in the cerebellar cortex.

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Lan Zhu

Full Text Available Learning to fear dangerous situations requires the participation of basolateral amygdala (BLA. In the present study, we provide evidence that BLA is necessary for the synaptic strengthening occurring during memory formation in the cerebellum in rats. In the cerebellar vermis the parallel fibers (PF to Purkinje cell (PC synapse is potentiated one day following fear learning. Pretraining BLA inactivation impaired such a learning-induced long-term potentiation (LTP. Similarly, cerebellar LTP is affected when BLA is blocked shortly, but not 6 h, after training. The latter result shows that the effects of BLA inactivation on cerebellar plasticity, when present, are specifically related to memory processes and not due to an interference with sensory or motor functions. These data indicate that fear memory induces cerebellar LTP provided that a heterosynaptic input coming from BLA sets the proper local conditions. Therefore, in the cerebellum, learning-induced plasticity is a heterosynaptic phenomenon that requires inputs from other regions. Studies employing the electrically-induced LTP in order to clarify the cellular mechanisms of memory should therefore take into account the inputs arriving from other brain sites, considering them as integrative units. Based on previous and the present findings, we proposed that BLA enables learning-related plasticity to be formed in the cerebellum in order to respond appropriately to new stimuli or situations.

Fast neutron radiation inactivation of Bacillus subtilis: Absorbed dose determination

International Nuclear Information System (INIS)

Song Lingli; Zheng Chun; Ai Zihui; Li Junjie; Dai Shaofeng

2011-01-01

In this paper, fast neutron inactivation effects of Bacillus subtilis were investigated with fission fast neutrons from CFBR-II reactor of INPC (Institute of Nuclear Physics and Chemistry) and mono-energetic neutrons from the Van de Graaff accelerator at Peking University. The method for determining the absorbed dose in the Bacillus subtilis suspension contained in test tubes is introduced. The absorbed dose, on account of its dependence on the volume and the form of confined state, was determined by combined experiments and Monte Carlo method. Using the calculation results of absorbed dose, the fast neutron inactivation effects on Bacillus subtilis were studied. The survival rates and absorbed dose curve was constructed. (authors)

The Wnt Transcriptional Switch: TLE Removal or Inactivation?

Science.gov (United States)

Ramakrishnan, Aravinda-Bharathi; Sinha, Abhishek; Fan, Vinson B; Cadigan, Ken M

2018-02-01

Many targets of the Wnt/β-catenin signaling pathway are regulated by TCF transcription factors, which play important roles in animal development, stem cell biology, and oncogenesis. TCFs can regulate Wnt targets through a "transcriptional switch," repressing gene expression in unstimulated cells and promoting transcription upon Wnt signaling. However, it is not clear whether this switch mechanism is a general feature of Wnt gene regulation or limited to a subset of Wnt targets. Co-repressors of the TLE family are known to contribute to the repression of Wnt targets in the absence of signaling, but how they are inactivated or displaced by Wnt signaling is poorly understood. In this mini-review, we discuss several recent reports that address the prevalence and molecular mechanisms of the Wnt transcription switch, including the finding of Wnt-dependent ubiquitination/inactivation of TLEs. Together, these findings highlight the growing complexity of the regulation of gene expression by the Wnt pathway. © 2017 WILEY Periodicals, Inc.

Kinetic studies of acid inactivation of alpha-amylase from Aspergillus oryzae

DEFF Research Database (Denmark)

Carlsen, Morten; Nielsen, Jens Bredal; Villadsen, John

1996-01-01

The stability of alpha-amylase from Aspergillus oryzae has been studied at different pH. The enzyme is extremely stable at neutral pH (pH 5-8), whereas outside this pH-range a substantial loss of activity is observed. The acid-inactivation of alpha-amylase from A. oryzae was monitored on...... regains part of its activity, and the reactivation process also follows first-order kinetics. The irreversible loss of activity is found not to result from a protease contamination of the protein samples. A proposed model, where irreversibly inactivated a-amylase is formed both directly from the active...

High pressure thermal inactivation of Clostridium botulinum type E endospores – kinetic modeling and mechanistic insights

Directory of Open Access Journals (Sweden)

Christian Andreas Lenz

2015-07-01

Full Text Available Cold-tolerant, neurotoxigenic, endospore forming Clostridium (C. botulinum type E belongs to the non-proteolytic physiological C. botulinum group II, is primarily associated with aquatic environments, and presents a safety risk for seafood. High pressure thermal (HPT processing exploiting the synergistic effect of pressure and temperature can be used to inactivate bacterial endospores.We investigated the inactivation of C. botulinum type E spores by (near isothermal HPT treatments at 300 – 1200 MPa at 30 – 75 °C for 1 s – 10 min. The occurrence of heat and lysozyme susceptible spore fractions after such treatments was determined. The experimental data were modeled to obtain kinetic parameters and represented graphically by isoeffect lines. In contrast to findings for spores of other species and within the range of treatment parameters applied, zones of spore stabilization (lower inactivation than heat treatments alone, large heat susceptible (HPT-induced germinated or lysozyme-dependently germinable (damaged coat layer spore fractions were not detected. Inactivation followed 1st order kinetics. DPA release kinetics allowed for insights into possible inactivation mechanisms suggesting a (poorly effective physiologic-like (similar to nutrient-induced germination at ≤ 450 MPa/≤ 45 °C and non-physiological germination at >500 MPa/>60 – 70 °C.Results of this study support the existence of some commonalities in the HPT inactivation mechanism of C. botulinum type E spores and Bacillus spores although both organisms have significantly different HPT resistance properties. The information presented here contributes to closing the gap in knowledge regarding the HPT inactivation of spore formers relevant to food safety and may help industrial implementation of HPT processing. The markedly lower HPT resistance of C. botulinum type E spores than spores from other C. botulinum types, could allow for the implementation of milder processes without

Abnormal X : autosome ratio, but normal X chromosome inactivation in human triploid cultures

Directory of Open Access Journals (Sweden)

Norwood Thomas H

2006-07-01

Full Text Available Abstract Background X chromosome inactivation (XCI is that aspect of mammalian dosage compensation that brings about equivalence of X-linked gene expression between females and males by inactivating one of the two X chromosomes (Xi in normal female cells, leaving them with a single active X (Xa as in male cells. In cells with more than two X's, but a diploid autosomal complement, all X's but one, Xa, are inactivated. This phenomenon is commonly thought to suggest 1 that normal development requires a ratio of one Xa per diploid autosomal set, and 2 that an early event in XCI is the marking of one X to be active, with remaining X's becoming inactivated by default. Results Triploids provide a test of these ideas because the ratio of one Xa per diploid autosomal set cannot be achieved, yet this abnormal ratio should not necessarily affect the one-Xa choice mechanism for XCI. Previous studies of XCI patterns in murine triploids support the single-Xa model, but human triploids mostly have two-Xa cells, whether they are XXX or XXY. The XCI patterns we observe in fibroblast cultures from different XXX human triploids suggest that the two-Xa pattern of XCI is selected for, and may have resulted from rare segregation errors or Xi reactivation. Conclusion The initial X inactivation pattern in human triploids, therefore, is likely to resemble the pattern that predominates in murine triploids, i.e., a single Xa, with the remaining X's inactive. Furthermore, our studies of XIST RNA accumulation and promoter methylation suggest that the basic features of XCI are normal in triploids despite the abnormal X:autosome ratio.

Inactivation of Bacillus subtilis spores by high pressure CO2 with high temperature.

Science.gov (United States)

Rao, Lei; Xu, Zhenzhen; Wang, Yongtao; Zhao, Feng; Hu, Xiaosong; Liao, Xiaojun

2015-07-16

The objective of this study was to investigate the inactivation of the Bacillus subtilis spores by high pressure CO2 combined with high temperature (HPCD+HT) and to analyze the clumping effect of the spores on their HPCD+HT resistance. The spores of B. subtilis were subjected to heat at 0.1 MPa and HPCD at 6.5-25 MPa, and 82 °C, 86 °C, and 91 °C for 0-120 min. The spores were effectively inactivated by HPCD+HT, but a protective effect on the spores was also found, which was closely correlated to the pressure, temperature and time. The spores treated by HPCD+HT at 6.5 and 10 MPa exhibited a two-stage inactivation curve of shoulder and log-linear regions whereas the spores at 15-25 MPa exhibited a three-stage inactivation curve of shoulder, log-linear and tailing regions, and these curves were well fitted to the Geeraerd model. Approximately 90% of pyridine-2,6-dicarboxylic acid (DPA) was released after HPCD+HT and the 90% DPA release time depend on the pressure and temperature. Moreover, the spore clumping in suspensions was examined by dynamic light scattering. The particle size of the spore suspensions increased with the increase of pressure, temperature and time, indicating the spore clumping. 0.1% Tween 80 as a surfactant inhibited the spore clumping and increased the inactivation ratio of the spores by HPCD+HT. These results indicated that the spore clumping enhanced the spores' resistance to HPCD+HT and induced a protective effect. Copyright © 2015 Elsevier B.V. All rights reserved.

Unilateral Hypothalamus Inactivation Prevents PTZ Kindling Development through Hippocampal Orexin Receptor 1 Modulation

Directory of Open Access Journals (Sweden)

Nasibe Akbari

2014-02-01

Full Text Available Introduction: Epilepsy is a neural disorder in which abnormal plastic changes during short and long term periods lead to increased excitability of brain tissue. Kindling is an animal model of epileptogenesis which results in changes of synaptic plasticity due to repetitive electrical or chemical sub-convulsive stimulations of the brain. Lateral hypothalamus, as the main niche of orexin neurons with extensive projections, is involved in sleep and wakefulness and so it affects the excitability of the brain. Therefore, we investigated whether lateral hypothalamic area (LHA inactivation or orexin-A receptor blocking could change convulsive behavior of acute and kindled PTZ treated animals and if glutamate has a role in this regard.  Methods: Kindling was induced by 40 mg/kg PTZ, every 48 hours up to 13 injections to each rat. Three consecutive stages 4 or 5 of convulsive behavior were used to ensure kindling. Lidocaine was injected stereotaxically to inactivate LHA, unilaterally. SB334867 used for orexin receptor 1 (OX1R blocking administered in CSF.  Results: We demonstrated that LHA inactivation prevented PTZ kindling and hence, excitability evolution. Hippocampal glutamate content was decreased due to LHA inactivation, OX1R antagonist infusion, lidocaine injection and kindled groups. In accordance, OX1R antagonist (SB334867 and lidocaine injection decreased PTZ single dose induced convulsive behavior. While orexin-A i.c.v. infusion increased hippocampal glutamate content, it did not change PTZ induced convulsive intensity.  Discussion: It is concluded that LHA inactivation prevented kindling development probably through orexin receptor antagonism. CSF orexin probably acts as an inhibitory step on convulsive intensity through another unknown process.

Mechanisms of poliovirus inactivation by the direct and indirect effects of ionizing radiation

International Nuclear Information System (INIS)

Ward, R.L.

1980-01-01

This study was designed to measure the effects of ionizing radiation on poliovirus particles when given under conditions where either direct (in broth) or indirect (in water) effects were predominant. Under direct conditions, inactivation of poliovirus was found to be due primarily to RNA damage, although capsid damage could account for about one-third of the viral inactivation. RNA damage did not appear to be due to strand breakage and therefore was probably caused primarily by base damage or crosslink formation. Capsid damage under direct irradiation conditions did not result in significant alterations of either the sedimentation coefficients or the isoelectric points of the poliovirus particles or detectable modification of the sizes of the viral proteins. It did, however, cause loss of availability to bind to host cells. Under indirect conditions no more than 25% of viral inactivation appeared to be due to RNA damage. However, the sedimentation coefficients and isoelectric points of the viral particles were greatly altered, and their abilities to bind to cells were lost at about three-fourths the rate of loss of infectivity. Capsid damage in this case did result in changes in the sizes of capsid proteins. Therefore, the majority of the radiation inactivation under indirect conditions appeared to be due to protein damage

Free chlorine and monochloramine inactivation kinetics of Aspergillus and Penicillium in drinking water.

Science.gov (United States)

Ma, Xiao; Bibby, Kyle

2017-09-01

Fungi are near-ubiquitous in potable water distribution systems, but the disinfection kinetics of commonly identified fungi are poorly studied. In the present study, laboratory scale experiments were conducted to evaluate the inactivation kinetics of Aspergillus fumigatus, Aspergillus versicolor, and Penicillium purpurogenum by free chlorine and monochloramine. The observed inactivation data were then fit to a delayed Chick-Watson model. Based on the model parameter estimation, the Ct values (integrated product of disinfectant concentration C and contact time t over defined time intervals) for 99.9% inactivation of the tested fungal strains ranged from 48.99 mg min/L to 194.7 mg min/L for free chlorine and from 90.33 mg min/L to 531.3 mg min/L for monochloramine. Fungal isolates from a drinking water system (Aspergillus versicolor and Penicillium purpurogenum) were more disinfection resistant than Aspergillus fumigatus type and clinical isolates. The required 99.9% inactivation Ct values for the tested fungal strains are higher than E. coli, a commonly monitored indicator bacteria, and within a similar range for bacteria commonly identified within water distribution systems, such as Mycobacterium spp. and Legionella spp. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mild processing applied to the inactivation of the main foodborne bacterial pathogens

DEFF Research Database (Denmark)

Barba Orellana, Francisco Jose; Koubaa, Mohamed; do Prado-Silva, Leonardo

2017-01-01

shelf-lives, pasteurization and commercial sterilization may result in numerous nutritional and sensory changes in foods. To address these disadvantages, mild processing methods (i.e., processing technologies for food preservation that apply mild temperature; ... contaminants have been developed. Scope and approach This review emphasizes the main applications of mild technologies aiming to the inactivation of the four main pathogenic bacteria of relevance for food safety as well as their mechanisms of action. Key findings and conclusions Mild processing technologies...... such as high pressure processing, ultrasounds, pulsed electric fields, UV-light, and atmospheric cold plasma may serve, in some conditions, as useful alternatives to commercial sterilization and pasteurization aiming to destroy foodborne pathogens. Each of these mild technologies has a specific mode...

The impact of atmospheric cold plasma treatment on inactivation of lipase and lipoxygenase of wheat germs

DEFF Research Database (Denmark)

Tolouie, Haniye; Mohammadifar, Mohammad Amin; Ghomi, Hamid

2018-01-01

Wheat germ is a by-product of milling process which contains large amount of nutrients. The shelf life of wheat germ could improve by inactivation of destructive endogenous enzymes especially lipase and lipoxygenase. In this work, the impact of atmospheric cold plasma treatment on the inactivation...... of lipase and lipoxygenase enzymes of wheat germ was studied. Dielectric barrier discharge plasma was utilized to treat wheat germs. The impact of treatment time and voltage of plasma on the inactivation of lipase and lipoxygenase were investigated as well. The higher voltage and treatment time led...

Inactivation of Salmonella during cocoa roasting and chocolate conching.

Science.gov (United States)

Nascimento, Maristela da Silva do; Brum, Daniela Merlo; Pena, Pamela Oliveira; Berto, Maria Isabel; Efraim, Priscilla

2012-10-15

The high heat resistance of Salmonella in foods with low water activity raises particular issues for food safety, especially chocolate, where outbreak investigations indicate that few colony-forming units are necessary to cause salmonellosis. This study evaluated the efficiency of cocoa roasting and milk chocolate conching in the inactivation of Salmonella 5-strain suspension. Thermal resistance of Salmonella was greater in nibs compared to cocoa beans upon exposure at 110 to 130°C. The D-values in nibs were 1.8, 2.2 and 1.5-fold higher than those calculated for cocoa beans at 110, 120 and 130°C. There was no significant difference (p>0.05) between the matrices only at 140°C. Since in the conching of milk chocolate the inactivation curves showed rapid death in the first 180 min followed by a lower inactivation rate, and two D-values were calculated. For the first time interval (0-180 min) the D-values were 216.87, 102.27 and 50.99 min at 50, 60 and 70°C, respectively. The other D-values were determined from the second time interval (180-1440 min), 1076.76 min at 50°C, 481.94 min at 60°C and 702.23 min at 70°C. The results demonstrated that the type of matrix, the process temperature and the initial count influenced the Salmonella resistance. Copyright © 2012 Elsevier B.V. All rights reserved.

Inactivation of infectious bovine rhinotracheitis virus by gamma irradiation

International Nuclear Information System (INIS)

Nonomiya, Takashi; Yamashiro, Tomio; Tsutsumi, Takamasa; Ito, Hitoshi; Ishigaki, Isao.

1990-01-01

Radiation inactivation of Infectious Boivne Rhinotracheitis (IBR) virus was investigated by suspending in a commercial preparation medium (c.p.m.) or IBR antibody free serum and irradiated at room temperature or dry ice frozen condition. Normal pooled serum was also analysed by electrophoresis with cellulose acetate membrane after irradiation at frozen and non-frozen condition. The virus inactivation was determined by MDBK cell line which 50 % tissue culture infectious dose (TCID 50 ) was calculated by Behrens Kaerber method. D 10 value at non-frozen condition in serum was obtained as 1.1-1.2 kGy and that in c.p.m. was 1.3-1.4 kGy. On the other hand, D 10 value was increased to 3.4-3.6 kGy in serum and 3.9 kGy in c.p.m. at frozen condition. On the irradiation effect of bovine serum, four peaks of albumin, α, β and γ-globulin fraction were obtained from non-irradiation and irradiated serum up to 2 kGy at non-frozen condition by electrophoresis. More than 4 kGy irradiation, the peaks of globulin fractions became not clear and at more than 8 kGy, changed to one large peak. On the other hand, these changes of electrophoretic patterns were not observed even at 30 kGy irradiation in frozen condition. From these results, necessary dose was decided as 20-25 kGy at frozen condition for inactivation of IBR virus in serum. (author)

Long-term effect of oral immunization against influenza with a gamma-inactivated vaccine in mice

International Nuclear Information System (INIS)

Noack, K.; Tischner, H.; Pohl, W.D.; Braeuniger, S.; Nordheim, W.

1986-01-01

NMRI mice were immunized orally twice within 10 days with an influenza vaccine inactivated by gamma radiation. The immunization with a relatively low dosis led to the occurence of low specific antibody titer in the lung lavage fluid up to 6th month. Despite of the low titer, immunized mice were protected against aerogenic infection for about 6 months. Protection was demonstrated in comparison to non-immunized mice by a limited increase of cells in bronchoalveolar lavage, low virus titer in the lung and survival of most animals after a lethal aerosol challenge with the live virus. (author)

Photodynamic inactivation of antibiotic-resistant pathogens

International Nuclear Information System (INIS)

Paronyan, M.H.

2015-01-01

Nowadays methicillin-resistant strain Staphylococcus aureus (MRSA) is one of the most widespread multiresistant bacteria. Photodynamic inactivation (PDI) of microorganisms by photosensitizers (PS) may be an effective and alternative therapeutic option against antibiotic resistant bacteria. The effectiveness of new PS cationic porphyrin Zn-TBut4PyP was tested on two strains of S. aureus (MRSA and methicillin-sensitive S. aureus). It is shown that Zn-TBut4PyP has high photodynamic activity against both strains

Effect of water content and temperature on inactivation kinetics of myrosinase in broccoli (Brassica oleracea var. italica).

Science.gov (United States)

Oliviero, T; Verkerk, R; Van Boekel, M A J S; Dekker, M

2014-11-15

Broccoli belongs to the Brassicaceae plant family consisting of widely eaten vegetables containing high concentrations of glucosinolates. Enzymatic hydrolysis of glucosinolates by endogenous myrosinase (MYR) can form isothiocyanates with health-promoting activities. The effect of water content (WC) and temperature on MYR inactivation in broccoli was investigated. Broccoli was freeze dried obtaining batches with WC between 10% and 90% (aw from 0.10 to 0.96). These samples were incubated for various times at different temperatures (40-70°C) and MYR activity was measured. The initial MYR inactivation rates were estimated by the first-order reaction kinetic model. MYR inactivation rate constants were lower in the driest samples (10% WC) at all studied temperatures. Samples with 67% and 90% WC showed initial inactivation rate constants all in the same order of magnitude. Samples with 31% WC showed intermediate initial inactivation rate constants. These results are useful to optimise the conditions of drying processes to produce dried broccoli with optimal MYR retention for human health. Copyright © 2014 Elsevier Ltd. All rights reserved.

Reduction of porcine circovirus type 2 (PCV2 viremia by a reformulated inactivated chimeric PCV1-2 vaccine-induced humoral and cellular immunity after experimental PCV2 challenge

Directory of Open Access Journals (Sweden)

Seo Hwi

2012-10-01

Full Text Available Abstract Background The objective of the present study was to elucidate the humoral and cellular immune response mechanisms by which a reformulated inactivated chimeric PCV1-2 vaccine reduces the PCV2 viremia. Forty PCV2 seronegative 3-week-old pigs were randomly divided into the following four groups: vaccinated challenged (T01, vaccinated non-challenged (T02, non-vaccinated challenged (T03, and non-vaccinated non-challenged (T04 animals. The pigs in groups T01 and T02 were immunized with a reformulated inactivated chimeric PCV1-2 vaccine (Fostera™ PCV; Pfizer Animal Health administered as a 2.0 ml dose at 21 days of age. At 35 days of age (0 days post-challenge, the pigs in groups T01 and T03 were inoculated intranasally with 2 ml each of PCV2b. Results A reduction of PCV2 viremia coincided with the appearance of both PCV2-specific neutralizing antibodies (NA and interferon-γ-secreting cells (IFN-γ-SCs in the vaccinated animals. However, the presence of anti-PCV2 IgG antibodies did not correlate with the reduction of PCV2 viremia. Lymphocyte subset analysis indicated that the numbers of CD3+ and CD4+ cells increased in vaccinated animals but the numbers of CD4+ cells decreased transiently in non-vaccinated animals. The observation of a delayed type hypersensitivity response in only the vaccinated animals also supports a CD4+ cell-associated protective cellular immune response induced by the reformulated inactivated chimeric PCV1-2 vaccine. Conclusions The induction of PCV2-specific NA and IFN-γ-SCs, and CD4+ cells by the reformulated inactivated chimeric PCV1-2 vaccine is the important protective immune response leading to reduction of the PCV2 viremia and control of the PCV2 infection. To our knowledge this is the first demonstration of protective humoral and cellular immunity induced by the reformulated inactivated chimeric PCV1-2 vaccine and its effect on reduction of PCV2 viremia by vaccination.

Immunopotentiators Improve the Efficacy of Oil-Emulsion-Inactivated Avian Influenza Vaccine in Chickens, Ducks and Geese.

Directory of Open Access Journals (Sweden)

Jihu Lu

Full Text Available Combination of CVCVA5 adjuvant and commercial avian influenza (AI vaccine has been previously demonstrated to provide good protection against different AI viruses in chickens. In this study, we further investigated the protective immunity of CVCVA5-adjuvanted oil-emulsion inactivated AI vaccine in chickens, ducks and geese. Compared to the commercial H5 inactivated vaccine, the H5-CVCVA5 vaccine induced significantly higher titers of hemaglutinin inhibitory antibodies in three lines of broiler chickens and ducks, elongated the antibody persistence periods in geese, elevated the levels of cross serum neutralization antibody against different clade and subclade H5 AI viruses in chicken embryos. High levels of mucosal antibody were detected in chickens injected with the H5 or H9-CVCA5 vaccine. Furthermore, cellular immune response was markedly improved in terms of increasing the serum levels of cytokine interferon-γ and interleukine 4, promoting proliferation of splenocytes and upregulating cytotoxicity activity in both H5- and H9-CVCVA5 vaccinated chickens. Together, these results provide evidence that AI vaccines supplemented with CVCVA5 adjuvant is a promising approach for overcoming the limitation of vaccine strain specificity of protection.

Role of cloned carotenoid genes expressed in Escherichia coli in protecting against inactivation by near-UV light and specific phototoxic molecules

International Nuclear Information System (INIS)

Tuveson, R.W.; Larson, R.A.; Kagan, J.

1988-01-01

Genes controlling carotenoid synthesis were cloned from Erwinia herbicola and expressed in an Escherichia coli strain. Carotenoids protect against high fluences of near-UV (NUV; 320 to 400 nm) but not against far-UV (200-300 nm). Protection of E. coli cells was not observed following treatment with either psoralen or 8-methoxypsoralen plus NUV. However, significant protection of cells producing carotenoids was observed with three photosensitizing molecules activated by NUV (alpha-terthienyl, harmine, and phenylheptatriyne) which are thought to have the membrane as an important lethal target. Protection of carotenoid-producing cells against inactivation was not observed with acridine orange plus visible light but was seen with toluidine blue O plus visible light

Multi-Layered TiO2 Films towards Enhancement of Escherichia coli Inactivation

Directory of Open Access Journals (Sweden)

Sorachon Yoriya

2016-09-01

Full Text Available Crystalline TiO2 has shown its great photocatalytic properties in bacterial inactivation. This work presents a design fabrication of low-cost, layered TiO2 films assembled reactors and a study of their performance for a better understanding to elucidate the photocatalytic effect on inactivation of E. coli in water. The ability to reduce the number of bacteria in water samples for the layered TiO2 composing reactors has been investigated as a function of time, while varying the parameters of light sources, initial concentration of bacteria, and ratios of TiO2 film area and volume of water. Herein, the layered TiO2 films have been fabricated on the glass plates by thermal spray coating prior to screen printing, allowing a good adhesion of the films. Surface topology and crystallographic phase of TiO2 for the screen-printed active layer have been characterized, resulting in the ratio of anatase:rutile being 80:20. Under exposure to sunlight and a given condition employed in this study, the optimized film area:water volume of 1:2.62 has shown a significant ability to reduce the E. coli cells in water samples. The ratio of surface area of photocatalytic active base to volume of water medium is believed to play a predominant role facilitating the cells inactivation. The kinetic rate of inactivation and its behavior are also described in terms of adsorption of reaction species at different contact times.

Validation of γ-radiation and ultraviolet as a new inactivators for foot and mouth disease virus in comparison with the traditional methods

Science.gov (United States)

Mahdy, Safy El din; Hassanin, Amr Ismail; Gamal El-Din, Wael Mossad; Ibrahim, Ehab El-Sayed; Fakhry, Hiam Mohamed

2015-01-01

Aim: The present work deals with different methods for foot and mouth disease virus (FMDV) inactivation for serotypes O/pan Asia, A/Iran05, and SAT-2/2012 by heat, gamma radiation, and ultraviolet (UV) in comparison with the traditional methods and their effects on the antigenicity of viruses for production of inactivated vaccines. Materials and Methods: FMDV types O/pan Asia, A/Iran05, and SAT-2/2012 were propagated in baby hamster kidney 21 (BHK21) and titrated then divided into five parts; the first part inactivated with heat, the second part inactivated with gamma radiation, the third part inactivated with UV light, the fourth part inactivated with binary ethylamine, and the last part inactivated with combination of binary ethylamine and formaldehyde (BEI+FA). Evaluate the method of inactivation via inoculation in BHK21, inoculation in suckling baby mice and complement fixation test then formulate vaccine using different methods of inactivation then applying the quality control tests to evaluate each formulated vaccine. Results: The effect of heat, gamma radiation, and UV on the ability of replication of FMDV “O/pan Asia, A/Iran05, and SAT-2/2012” was determined through BHK cell line passage. Each of the 9 virus aliquots titer 108 TCID50 (3 for each strain) were exposed to 37, 57, and 77°C for 15, 30, and 45 min. Similarly, another 15 aliquots (5 for each strain) contain 1 mm depth of the exposed samples in petri-dish was exposed to UV light (252.7 nm wavelength: One foot distance) for 15, 30, 45, 60, and 65 min. Different doses of gamma radiation (10, 20, 25, 30, 35, 40, 45, 50, 55, and 60 KGy) were applied in a dose rate 0.551 Gy/s for each strain and repeated 6 times for each dose. FMDV (O/pan Asia, A/Iran05, and SAT-2/2012) were inactivated when exposed to heat ≥57°C for 15 min. The UV inactivation of FMDV (O/pan Asia and SAT-2) was obtained within 60 min and 65 min for type A/Iran05. The ideal dose for inactivation of FMDV (O/pan Asia, A/Iran05

Validation of γ-radiation and ultraviolet as a new inactivators for foot and mouth disease virus in comparison with the traditional methods

Directory of Open Access Journals (Sweden)

Safy El din Mahdy

2015-09-01

Full Text Available Aim: The present work deals with different methods for foot and mouth disease virus (FMDV inactivation for serotypes O/pan Asia, A/Iran05, and SAT-2/2012 by heat, gamma radiation, and ultraviolet (UV in comparison with the traditional methods and their effects on the antigenicity of viruses for production of inactivated vaccines. Materials and Methods: FMDV types O/pan Asia, A/Iran05, and SAT-2/2012 were propagated in baby hamster kidney 21 (BHK21 and titrated then divided into five parts; the first part inactivated with heat, the second part inactivated with gamma radiation, the third part inactivated with UV light, the fourth part inactivated with binary ethylamine, and the last part inactivated with combination of binary ethylamine and formaldehyde (BEI+FA. Evaluate the method of inactivation via inoculation in BHK21, inoculation in suckling baby mice and complement fixation test then formulate vaccine using different methods of inactivation then applying the quality control tests to evaluate each formulated vaccine. Results: The effect of heat, gamma radiation, and UV on the ability of replication of FMDV "O/pan Asia, A/Iran05, and SAT-2/2012" was determined through BHK cell line passage. Each of the 9 virus aliquots titer 108 TCID50 (3 for each strain were exposed to 37, 57, and 77°C for 15, 30, and 45 min. Similarly, another 15 aliquots (5 for each strain contain 1 mm depth of the exposed samples in petri-dish was exposed to UV light (252.7 nm wavelength: One foot distance for 15, 30, 45, 60, and 65 min. Different doses of gamma radiation (10, 20, 25, 30, 35, 40, 45, 50, 55, and 60 KGy were applied in a dose rate 0.551 Gy/s for each strain and repeated 6 times for each dose. FMDV (O/pan Asia, A/Iran05, and SAT-2/2012 were inactivated when exposed to heat ≥57°C for 15 min. The UV inactivation of FMDV (O/pan Asia and SAT-2 was obtained within 60 min and 65 min for type A/Iran05. The ideal dose for inactivation of FMDV (O/pan Asia, A

Biocontrol interventions for inactivation of foodborne pathogens on produce

Science.gov (United States)

Post-harvest interventions for control of foodborne pathogens on minimally processed foods are crucial for food safety. Biocontrol interventions have the primary objective of developing novel antagonists in combinations with physical and chemical interventions to inactivate pathogenic microbes. Ther...

Recovery of prostacyclin synthesis in vascular smooth muscle cells following self-inactivation and requirement for growth factors

International Nuclear Information System (INIS)

Bailey, J.M.; Hla, T.T.; Pash, J.M.

1986-01-01

The cyclooxygenase enzyme system is a prime example of a metabolic pathway that is regulated by self inactivation. This is believed to occur in part via the irreversible reaction of the endoperoxide intermediate species with the cyclooxygenase enzyme. This inactivation and recovery of activity is similar to the inactivation observed with aspirin which irreversibly acetylates the enzyme. Self inactivation was studied in cultured rat and bovine aorta smooth muscle cells. The production of the prostanoid PGI2 was demonstrated by incubation of a monolayer of cells with 12 μM C-14 labeled arachidonic acid. Products were analyzed by thin layer chromatography and identified by their comigration with authentic standards and confirmed by gas chromatography/mass spectrometry. Preincubation of the cells for 10 minutes with arachidonic acid at concentrations as low as 1 μg/mL inactivated the cells to a second challenge with radiolabeled arachidonic acid. Recovery from self inactivation took place over a three hour time period and was similar to the recovery observed with aspirin pretreatment. Recovery was inhibited by addition of 10 μg/mL cycloheximide to the medium indicating that it involves synthesis of cyclooxygenase protein. Epidermal growth factor was identified as a serum factor responsible for the rapid recovery of cyclooxygenase activity in rat and bovine aorta smooth muscle cells

Indicators for suicide substrate inactivation: A kinetic investigation

Indian Academy of Sciences (India)

Sharmistha Dhatt

2017-11-20

Nov 20, 2017 ... practical ones, that can decisively conclude enzyme inactivation are considered. Steady-state approximation ... nase 1 and 2 enzymes), Exemesteme - a drug used in the treatment of breast cancer (inhibitor of aromatase enzyme), AZT and .... for a next indicator that can serve as a diagnostic tool for enzyme ...

Stable X chromosome inactivation involves the PRC1 Polycomb complex and requires histone MACROH2A1 and the CULLIN3/SPOP ubiquitin E3 ligase

DEFF Research Database (Denmark)

Hernández-Muñoz, Inmaculada; Lund, Anders H; van der Stoop, Petra

2005-01-01

X inactivation involves the stable silencing of one of the two X chromosomes in XX female mammals. Initiation of this process occurs during early development and involves Xist (X-inactive-specific transcript) RNA coating and the recruitment of Polycomb repressive complex (PRC) 2 and PRC1 proteins...

Adsorption, sedimentation, and inactivation of E. coli within wastewater treatment wetlands.

Science.gov (United States)

Boutilier, L; Jamieson, R; Gordon, R; Lake, C; Hart, W

2009-09-01

Bacteria fate and transport within constructed wetlands must be understood if engineered wetlands are to become a reliable form of wastewater treatment. This study investigated the relative importance of microbial treatment mechanisms in constructed wetlands treating both domestic and agricultural wastewater. Escherichia coli (E. coli) inactivation, adsorption, and settling rates were measured in the lab within two types of wastewater (dairy wastewater lagoon effluent and domestic septic tank effluent). In situ E. coli inactivation was also measured within a domestic wastewater treatment wetland and the adsorption of E. coli was also measured within the wetland effluent. Inactivation of E. coli appears to be the most significant contributor to E. coli removal within the wastewaters and wetland environments examined in this study. E. coli survived longer within the dairy wastewater (DW) compared to the domestic wastewater treatment wetland water (WW). First order rate constants for E. coli inactivation within the WW in the lab ranged from 0.09 day(-1) (d(-1)) at 7.6 degrees C to 0.18d(-1) at 22.8 degrees C. The average in situ rate constant observed within the domestic wetland ranged from 0.02 d(-1) to 0.03 d(-1) at an average water temperature of 17 degrees C. First order rate constants for E. coli inactivation within the DW ranged from 0.01 d(-1) at 7.7 degrees C to 0.04 d(-1) at 24.6 degrees C. Calculated distribution coefficients (K(d)) were 19,000 mL g(-1), 324,000 mL g(-1), and 293 mL g(-1) for E. coli with domestic septic tank effluent (STE), treated wetland effluent (WLE), and DW, respectively. Approximately 50%, 20%, and 90% of E. coli were "free floating" or associated with particles 5 microm within both the STE and DW, settling did not appear to contribute to E. coli removal within sedimentation experiments, indicating that the particles the bacteria were associated with had very small settling velocities. The results of this study highlight the

Inactivation of Escherichia coli in water by pulsed dielectric barrier discharge in coaxial reactor.

Science.gov (United States)

Hernández-Arias, A N; Rodríguez-Méndez, B G; López-Callejas, R; Alcántara-Díaz, D; Valencia-Alvarado, R; Mercado-Cabrera, A; Peña-Eguiluz, R; Muñoz-Castro, A E; Barocio, S R; de la Piedad-Beneitez, A

2012-09-01

An experimental study of ATCC (American Type Culture Collection) 8739 Escherichia coli bacteria inactivation in water by means of pulsed dielectric barrier discharge (PDBD) atmospheric pressure plasmas is presented. Plasma is generated by an adjustable power source capable of supplying high voltage 25 kV pulses, ∼30 μs long and at a 500 Hz frequency. The process was conducted in a ∼152 cm(3) cylindrical stainless steel coaxial reactor, endowed with a straight central electrode and a gas inlet. The bacterial concentration in water was varied from 10(3) up to 10(8) E. coli cells per millilitre. The inactivation was achieved without gas flow in the order of 82% at 10(8) colony-forming units per millilitre (CFU mL(-1)) concentrations in 600 s. In addition, oxygen was added to the gas supply in order to increase the ozone content in the process, raising the inactivation percentage to the order of 90% in the same treatment time. In order to reach a higher efficiency however, oxygen injection modulation is applied, leading to inactivation percentages above 99.99%. These results are similarly valid for lower bacterial concentrations.

Inactivation of 12 viruses by heating steps applied during manufacture of a hepatitis B vaccine

NARCIS (Netherlands)

Lelie, P. N.; Reesink, H. W.; Lucas, C. J.

1987-01-01

The efficacy of two heating cycles (90 sec at 103 degrees C and 10 hr at 65 degrees C) used during manufacture of a plasma-derived hepatitis-B vaccine was validated for the inactivation of 12 virus families. A period of 15 min warming up to 65 degrees C had already completely inactivated

Linear energy transfer (LET) effects in the radiation-induced inactivation of papain

International Nuclear Information System (INIS)

Bisby, R.H.; Cundall, R.B.; Sims, H.E.; Burns, W.G.

1977-01-01

The inactivation of dilute aqueous solutions of papain by radiations of varying linear energy transfer has been studied in N 2 , N 2 0 and O 2 -saturated solutions. The results obtained with low LET radiation are very similar to those previously reported by Lin et al (Radiation Res.;62:438(1975)). The additional data obtained at higher LET, when radical product yields are reduced and the yield of hydrogen peroxide is increased, show that the hydrogen atom is more important in the inactivation of papain than previously considered. (author)

Microbial inactivation and cytotoxicity evaluation of UV irradiated coconut water in a novel continuous flow spiral reactor.

Science.gov (United States)

Bhullar, Manreet Singh; Patras, Ankit; Kilanzo-Nthenge, Agnes; Pokharel, Bharat; Yannam, Sudheer Kumar; Rakariyatham, Kanyasiri; Pan, Che; Xiao, Hang; Sasges, Michael

2018-01-01

A continuous-flow UV reactor operating at 254nm wave-length was used to investigate inactivation of microorganisms including bacteriophage in coconut water, a highly opaque liquid food. UV-C inactivation kinetics of two surrogate viruses (MS2, T1UV) and three bacteria (E. coli ATCC 25922, Salmonella Typhimurium ATCC 13311, Listeria monocytogenes ATCC 19115) in buffer and coconut water were investigated (D 10 values ranging from 2.82 to 4.54mJ·cm -2 ). A series of known UV-C doses were delivered to the samples. Inactivation levels of all organisms were linearly proportional to UV-C dose (r 2 >0.97). At the highest dose of 30mJ·cm -2 , the three pathogenic organisms were inactivated by >5 log 10 (pUV-C irradiation effectively inactivated bacteriophage and pathogenic microbes in coconut water. The inactivation kinetics of microorganisms were best described by log linear model with a low root mean square error (RMSE) and high coefficient of determination (r 2 >0.97). Models for predicting log reduction as a function of UV-C irradiation dose were found to be significant (pUV-C treatment did not generate cytotoxic compounds in the coconut water. This study clearly demonstrated that high levels of inactivation of pathogens can be achieved in coconut water, and suggested potential method for UV-C treatment of other liquid foods. This research paper provides scientific evidence of the potential benefits of UV-C irradiation in inactivating bacterial and viral surrogates at commercially relevant doses of 0-120mJ·cm -2 . The irradiated coconut water showed no cytotoxic effects on normal intestinal and healthy mice liver cells. UV-C irradiation is an attractive food preservation technology and offers opportunities for horticultural and food processing industries to meet the growing demand from consumers for healthier and safe food products. This study would provide technical support for commercialization of UV-C treatment of beverages. Copyright © 2017 Elsevier Ltd. All

Saturation of SERCA's lipid annulus may protect against its thermal inactivation

International Nuclear Information System (INIS)

Fajardo, Val Andrew; Trojanowski, Natalie; Castelli, Laura M.; Miotto, Paula M.; Amoye, Foyinsola; Ward, Wendy E.; Tupling, A. Russell; LeBlanc, Paul J.

2017-01-01

The sarco(endo)plasmic reticulum Ca 2+ -ATPase (SERCA) pumps are integral membrane proteins that catalyze the active transport of Ca 2+ into the sarcoplasmic reticulum, thereby eliciting muscle relaxation. SERCA pumps are highly susceptible to oxidative damage, and cytoprotection of SERCA dampens thermal inactivation and is a viable therapeutic strategy in combating diseases where SERCA activity is impaired, such as muscular dystrophy. Here, we sought to determine whether increasing the percent of saturated fatty acids (SFA) within SERCA's lipid annulus through diet could protect SERCA pumps from thermal inactivation. Female Wistar rats were fed either a semi-purified control diet (AIN93G, 7% soybean oil by weight) or a modified AIN93G diet containing high SFA (20% lard by weight) for 17 weeks. Soleus muscles were extracted and SERCA lipid annulus and activity under thermal stress were analyzed. Our results show that SERCA's lipid annulus is abundant with short-chain (12–14 carbon) fatty acids, which corresponds well with SERCA's predicted bilayer thickness of 21 Å. Under control-fed conditions, SERCA's lipid annulus was already highly saturated (79%), and high-fat feeding did not increase this any further. High-fat feeding did not mitigate the reductions in SERCA activity seen with thermal stress; however, correlational analyses revealed significant and strong associations between % SFA and thermal stability of SERCA activity with greater %SFA being associated with lower thermal inactivation and greater % polyunsaturation and unsaturation index being associated with increased thermal inactivation. Altogether, these findings show that SERCA's lipid annulus may influence its susceptibility to oxidative damage, which could have implications in muscular dystrophy and age-related muscle wasting. - Highlights: • SERCA's lipid annulus in rat soleus was measured after immunoconcentration. • Short fatty acid chains surround SERCA and

IL26 gene inactivation in Equidae.

Science.gov (United States)

Shakhsi-Niaei, M; Drögemüller, M; Jagannathan, V; Gerber, V; Leeb, T

2013-12-01

Interleukin-26 (IL26) is a member of the IL10 cytokine family. The IL26 gene is located between two other well-known cytokines genes of this family encoding interferon-gamma (IFNG) and IL22 in an evolutionary conserved gene cluster. In contrast to humans and most other mammals, mice lack a functional Il26 gene. We analyzed the genome sequences of other vertebrates for the presence or absence of functional IL26 orthologs and found that the IL26 gene has also become inactivated in several equid species. We detected a one-base pair frameshift deletion in exon 2 of the IL26 gene in the domestic horse (Equus caballus), Przewalski horse (Equus przewalskii) and donkey (Equus asinus). The remnant IL26 gene in the horse is still transcribed and gives rise to at least five alternative transcripts. None of these transcripts share a conserved open reading frame with the human IL26 gene. A comparative analysis across diverse vertebrates revealed that the IL26 gene has also independently been inactivated in a few other mammals, including the African elephant and the European hedgehog. The IL26 gene thus appears to be highly variable, and the conserved open reading frame has been lost several times during mammalian evolution. © 2013 The Authors, Animal Genetics © 2013 Stichting International Foundation for Animal Genetics.

Functional inactivation of dorsal medial striatum alters behavioral flexibility and recognition process in mice.

Science.gov (United States)

Qiao, Yanhua; Wang, Xingyue; Ma, Lian; Li, Shengguang; Liang, Jing

2017-10-01

Deficits in behavioral flexibility and recognition memory are commonly observed in mental illnesses and neurodegenerative diseases. Abnormality of the striatum has been implicated in an association with the pathology of these diseases. However, the exact roles of striatal heterogeneous structures in these cognitive functions are still unknown. In the present study, we investigated the effects of suppressing neuronal activity in the dorsomedial striatum (DMStr) and nucleus accumbens core (NAcC) on reversal learning and novelty recognition in mice. In addition, the locomotor activity, anxiety-like behavior and social interaction were analyzed. Neuronal inactivation was performed by expressing lentivirus-mediated tetanus toxin (TeNT) in the target regions. The results showed that reversal learning was facilitated by neuronal inactivation in the DMStr but not the NAcC, which was attributable to accelerated extinction of acquired strategy but not to impaired memory retention. Furthermore, mice with NAcC inactivation spent more time exploring a novel object than a familiar one, comparable to control mice. In contrast, mice with DMStr inactivation exhibited no preference to a novel environment during the novel object or place recognition test. The DMStr mice also exhibited decreased anxiety level. No phenotypic effect was observed in the locomotion or social interaction in mice with either DMStr or NAcC inactivation. Altogether, these findings suggest that the DMStr but not the ventral area of the striatum plays a crucial role in learning and memory by coordinating spatial exploration as well as mediating information updating. Copyright © 2017 Elsevier Inc. All rights reserved.

Far-UVC light applications: sterilization of MRSA on a surface and inactivation of aerosolized influenza virus

Science.gov (United States)

Welch, David; Buonanno, Manuela; Shuryak, Igor; Randers-Pehrson, Gerhard; Spotnitz, Henry M.; Brenner, David J.

2018-02-01

Methicillin-resistant Staphylococcus aureus (MRSA) and influenza A virus are two of the major targets for new antimicrobial technologies. In contrast to conventional germicidal lamps emitting primarily at 254 nm, which are both carcinogenic and cataractogenic, recent work has shown the potential of far-UVC technology, mainly between 207 and 222 nm, to be an effective means of sterilization of pathogens without apparent harm to mammalian cells. This is because, due to its strong absorbance in biological materials, far-UVC light cannot penetrate even the outer (non living) layers of human skin or eye; however, because bacteria and viruses are of micrometer or smaller dimensions, far-UVC can penetrate and inactivate them. With this report, we present progress on in vitro tests to inactivate MRSA on a surface using far-UVC light from a laser delivered using an optical diffuser. Qualitative and quantitative results show that this means of far-UVC exposure is adequate to inactivate MRSA with a dose comparable to that which would be required using a conventional germicidal lamp. Also included is a report on progress on inactivation of aerosolized influenza A virus. A custom benchtop aerosol exposure chamber was constructed and used to determine the effectiveness of far- UVC. Results indicate that far-UVC efficiently inactivates airborne aerosolized viruses, with a very low dose of 2 mJ/cm2 of 222-nm light inactivating >95% of aerosolized H1N1 influenza virus. Together these studies help to further establish far-UVC technology as a promising, safe and inexpensive tool for sterilization in many environments.

Inactivation of Byssochlamys nivea ascospores in strawberry puree by high pressure, power ultrasound and thermal processing.

Science.gov (United States)

Evelyn; Silva, F V M

2015-12-02

Byssochlamys nivea is a mold that can spoil processed fruit products and produce mycotoxins. In this work, high pressure processing (HPP, 600 MPa) and power ultrasound (24 kHz, 0.33 W/mL; TS) in combination with 75°C for the inactivation of four week old B. nivea ascospores in strawberry puree for up to 30 min was investigated and compared with 75°C thermal processing alone. TS and thermal processing can activate the mold ascospores, but HPP-75°C resulted in 2.0 log reductions after a 20 min process. For a 10 min process, HPP-75°C was better than 85°C alone in reducing B. nivea spores (1.4 vs. 0.2 log reduction), demonstrating that a lower temperature in combination with HPP is more effective for spore inactivation than heat alone at a higher temperature. The ascospore inactivation by HPP-thermal, TS and thermal processing was studied at different temperatures and modeled. Faster inactivation was achieved at higher temperatures for all the technologies tested, indicating the significant role of temperature in spore inactivation, alone or combined with other physical processes. The Weibull model described the spore inactivation by 600 MPa HPP-thermal (38, 50, 60, 75°C) and thermal (85, 90°C) processing, whereas the Lorentzian model was more appropriate for TS treatment (65, 70, 75°C). The models obtained provide a useful tool to design and predict pasteurization processes targeting B. nivea ascospores. Copyright © 2015 Elsevier B.V. All rights reserved.

Inactivation of Anandamide Signaling: A Continuing Debate

Directory of Open Access Journals (Sweden)

Wael E. Houssen

2010-10-01

Full Text Available Since the first endocannabinoid anandamide was identified in 1992, extensive research has been conducted to characterize the elements of the tightly controlled endocannabinoid signaling system. While it was established that the activity of endocannabinoids are terminated by a two-step process that includes cellular uptake and degradation, there is still a continuing debate about the mechanistic role of these processes in inactivating anandamide signals.

Infectious Causes of Cholesteatoma and Treatment of Infected Ossicles prior to Reimplantation by Hydrostatic High-Pressure Inactivation

Science.gov (United States)

Hinz, Rebecca

2015-01-01

Chronic inflammation, which is caused by recurrent infections, is one of the factors contributing to the pathogenesis of cholesteatoma. If reimplantation of autologous ossicles after a surgical intervention is intended, inactivation of planktonic bacteria and biofilms is desirable. High hydrostatic pressure treatment is a procedure, which has been used to inactivate cholesteatoma cells on ossicles. Here we discuss the potential inactivating effect of high hydrostatic pressure on microbial pathogens including biofilms. Recent experimental data suggest an incomplete inactivation at a pressure level, which is tolerable for the bone substance of ossicles and results at least in a considerable reduction of pathogen load. Further studies are necessary to access how far this quantitative reduction of pathogens is sufficient to prevent ongoing chronic infections, for example, due to forming of biofilms. PMID:25705686

Systems Biology of the Immune Response to Live and Inactivated Dengue Virus Vaccines

Science.gov (United States)

2017-09-01

AWARD NUMBER: W81XWH-16-2-0031 TITLE: Systems Biology of the Immune Response to Live and Inactivated Dengue Virus Vaccines PRINCIPAL...SUBTITLE 5a. CONTRACT NUMBER Systems Biology of the Immune Response to Live and Inactivated Dengue Virus Vaccines 5b. GRANT NUMBER W81XWH-16-2-0031 5c...adaptive (T and B cell) responses will be measured using molecular and cellular approaches and the data analyzed using a systems biology approach

Detection, fate and inactivation of pathogenic norovirus employing settlement and UV treatment in wastewater treatment facilities

International Nuclear Information System (INIS)

Barrett, M.; Fitzhenry, K.; O'Flaherty, V.; Dore, W.; Keaveney, S.; Cormican, M.; Rowan, N.; Clifford, E.

2016-01-01

It is accepted that discharged wastewaters can be a significant source of pathogenic viruses in receiving water bodies contributing to pollution and may in turn enter the human food chain and pose a risk to human health, thus norovirus (NoV) is often a predominant cause of gastroenteritis globally. Working with NoV poses particular challenges as it cannot be readily identified and detection by molecular methods does not assess infectivity. It has been proposed that the infectivity of NoV may be modelled through the use of an alternative virus; F-specific RNA (FRNA) bacteriophages; GA genotype and other FRNA bacteriophages have been used as a surrogate in studies of NoV inactivation. This study investigated the efficiency of novel pulsed ultraviolet irradiation and low pressure ultraviolet irradiation as a potential pathogen inactivation system for NoV and FRNA bacteriophage (GA) in secondary treated wastewaters. The role of UV dose and the impact of suspended solids concentration on removal efficiency were also examined. The study also investigated the role of settlement processes in wastewater treatment plants in removing NoV. While NoV inactivation could not be determined it was found that at a maximum UV dose of 6.9 J/cm"2 (6900 mJ/cm"2) an average 2.4 log removal of FRNA bacteriophage (GA) was observed; indicating the potential need for high UV doses to remove NoV if FRNA bacteriophage prove a suitable indicator for NoV. The study found that increasing concentrations of suspended solids impacted on PUV efficiency however, it appears the extent of the impact may be site specific. Furthermore, the study found that settlement processes can play a significant role in the removal of FRNA bacteriophage, thus potentially NoV. - Highlights: • Effectiveness of low pressure UV and novel high-intensity pulsed UV disinfection in NoVs removal. • Reduction of FRNA bacteriophage was seen in clarified wastewater after settling. • Adsorption of viral particles to solids

Detection, fate and inactivation of pathogenic norovirus employing settlement and UV treatment in wastewater treatment facilities

Energy Technology Data Exchange (ETDEWEB)

Barrett, M. [Microbial Ecology Laboratory, Microbiology, School of Natural sciences, National University of Ireland Galway (Ireland); Ryan Institute, National University of Ireland Galway (Ireland); College of Engineering and Informatics, National University of Ireland Galway (Ireland); Fitzhenry, K. [Ryan Institute, National University of Ireland Galway (Ireland); College of Engineering and Informatics, National University of Ireland Galway (Ireland); O' Flaherty, V. [Microbial Ecology Laboratory, Microbiology, School of Natural sciences, National University of Ireland Galway (Ireland); Ryan Institute, National University of Ireland Galway (Ireland); Dore, W.; Keaveney, S. [Marine Institute, Galway (Ireland); Cormican, M. [Ryan Institute, National University of Ireland Galway (Ireland); Centre for Health from Environment, Ryan Institute, National University of Ireland Galway (Ireland); Rowan, N. [Bioscience Research Institute, Athlone Institute of Technology (Ireland); Clifford, E., E-mail: eoghan.clifford@nuigalway.ie [Ryan Institute, National University of Ireland Galway (Ireland); College of Engineering and Informatics, National University of Ireland Galway (Ireland)

2016-10-15

It is accepted that discharged wastewaters can be a significant source of pathogenic viruses in receiving water bodies contributing to pollution and may in turn enter the human food chain and pose a risk to human health, thus norovirus (NoV) is often a predominant cause of gastroenteritis globally. Working with NoV poses particular challenges as it cannot be readily identified and detection by molecular methods does not assess infectivity. It has been proposed that the infectivity of NoV may be modelled through the use of an alternative virus; F-specific RNA (FRNA) bacteriophages; GA genotype and other FRNA bacteriophages have been used as a surrogate in studies of NoV inactivation. This study investigated the efficiency of novel pulsed ultraviolet irradiation and low pressure ultraviolet irradiation as a potential pathogen inactivation system for NoV and FRNA bacteriophage (GA) in secondary treated wastewaters. The role of UV dose and the impact of suspended solids concentration on removal efficiency were also examined. The study also investigated the role of settlement processes in wastewater treatment plants in removing NoV. While NoV inactivation could not be determined it was found that at a maximum UV dose of 6.9 J/cm{sup 2} (6900 mJ/cm{sup 2}) an average 2.4 log removal of FRNA bacteriophage (GA) was observed; indicating the potential need for high UV doses to remove NoV if FRNA bacteriophage prove a suitable indicator for NoV. The study found that increasing concentrations of suspended solids impacted on PUV efficiency however, it appears the extent of the impact may be site specific. Furthermore, the study found that settlement processes can play a significant role in the removal of FRNA bacteriophage, thus potentially NoV. - Highlights: • Effectiveness of low pressure UV and novel high-intensity pulsed UV disinfection in NoVs removal. • Reduction of FRNA bacteriophage was seen in clarified wastewater after settling. • Adsorption of viral particles

Inactivation of Mycobacterium paratuberculosis in cows' milk at pasteurization temperatures.

Science.gov (United States)

Grant, I R; Ball, H J; Neill, S D; Rowe, M T

1996-01-01

The thermal inactivation of 11 strains of Mycobacterium paratuberculosis at pasteurization temperatures was investigated. Cows' milk inoculated with M. paratuberculosis at two levels (10(7) and 10(4) CFU/ml) was pasteurized in the laboratory by (i) a standard holder method (63.5 degrees C for 30 min) and (ii) a high-temperature, short-time (HTST) method (71.7 degrees C for 15 s). Additional heating times of 5, 10, 15, 20, and 40 min at 63.5 degrees C were included to enable the construction of a thermal death curve for the organism. Viability after pasteurization was assessed by culture on Herrold's egg yolk medium containing mycobactin J (HEYM) and in BACTEC Middlebrook 12B radiometric medium supplemented with mycobactin J and sterile egg yolk emulsion. Confirmation of acid-fast survivors of pasteurization as viable M. paratuberculosis cells was achieved by subculture on HEYM to indicate viability coupled with PCR using M. paratuberculosis-specific 1S900 primers. When milk was initially inoculated with 10(6) to 10(7) CFU of M. paratuberculosis per ml, M. paratuberculosis cells were isolated from 27 of 28 (96%) and 29 of 34 (85%) pasteurized milk samples heat treated by the holder and HTST methods, respectively. Correspondingly, when 10(3) to 10(4) CFU of M. paratuberculosis per ml of milk were present before heat treatment, M. paratuberculosis cells were isolated from 14 of 28 (50%) and 19 of 33 (58%) pasteurized milk samples heat treated by the holder and HTST methods, respectively. The thermal death curve for M. paratuberculosis was concave in shape, exhibiting a rapid initial death rate followed by significant "tailing." Results indicate that when large numbers of M. paratuberculosis cells are present in milk, the organism may not be completely inactivated by heat treatments simulating holder and HTST pasteurization under laboratory conditions. PMID:8593064

Inactivation and mutation induction in Saccharomyces cerevisiae exposed to simulated sunlight: evaluation of action spectra.

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Schenk-Meuser, K; Pawlowsky, K; Kiefer, J

1992-07-15

The effectiveness of polychromatic light irradiation was investigated for haploid yeast cells. Inactivation and mutation induction were measured in both a RAD-wildtype strain and an excision-repair defective strain. The behaviour of vegetative "wet" cells was compared to that of dehydrated cells. The aim of the study was to assess the interaction of UVC with other wavelengths in cells of different states of humidity. The irradiation procedure was therefore carried out using a solar simulator either with full spectrum or with a UVC-blocking filter (modified sunlight) added. The results were analysed on the basis of separately determined action spectra. The summation of the efficiency of individual wavelengths was compared to the values obtained from polychromatic irradiation. It is shown that the effects caused by the whole-spectrum irradiation in wet cells can be predicted sufficiently from the calculation, while dried wildtype cells exhibit higher mutation rates. Thus it can be assumed that drying-specific damage leads to lethal and mutagenic lesions which are processed in different ways, causing a synergistic behaviour in mutation induction. Irradiation of vegetative cells with modified sunlight (UVC-) results in less inactivation and lower mutation rates than were calculated. From these results it can be concluded that this antagonistic behaviour is caused by the interaction of near-UV photoproducts.

Inactivation of avirulent Yersinia pestis on food and food contact surfaces by ultraviolet light and freezing.

Science.gov (United States)

Sommers, Christopher H; Sheen, Shiowshuh

2015-09-01

Yersinia pestis, the causative agent of plague, can occasionally be contracted as a naso-pharyngeal or gastrointestinal illness through consumption of contaminated meat. In this study, the use of 254 nm ultraviolet light (UV-C) to inactivate a multi-isolate cocktail of avirulent Y. pestis on food and food contact surfaces was investigated. When a commercial UV-C conveyor was used (5 mW/cm(2)/s) 0.5 J/cm(2) inactivated >7 log of the Y. pestis cocktail on agar plates. At 0.5 J/cm(2), UV-C inactivated ca. 4 log of Y. pestis in beef, chicken, and catfish, exudates inoculated onto high density polypropylene or polyethylene, and stainless steel coupons, and >6 log was eliminated at 1 J/cm(2). Approximately 1 log was inactivated on chicken breast, beef steak, and catfish fillet surfaces at a UV-C dose of 1 J/cm(2). UV-C treatment prior to freezing of the foods did not increase the inactivation of Y. pestis over freezing alone. These results indicate that routine use of UV-C during food processing would provide workers and consumers some protection against Y. pestis. Published by Elsevier Ltd.

Inactivation of high-risk human papillomaviruses by Holder pasteurization: implications for donor human milk banking.

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Donalisio, Manuela; Cagno, Valeria; Vallino, Marta; Moro, Guido E; Arslanoglu, Sertac; Tonetto, Paola; Bertino, Enrico; Lembo, David

2014-01-01

Several studies have recently reported the detection of oncogenic human papillomaviruses (HPV) in human milk of a minority of lactating mothers. These findings raised safety concerns in the context of human donor milk banking given the potential risk of HPV transmission to recipient infants. The aim of this study was to investigate whether the Holder pasteurization, a procedure currently in use in human donor milk banks for milk pasteurization, completely inactivates high-risk and low-risk HPV. HPV pseudoviruses (PsV) were generated, spiked into cell culture medium or donor human milk and subjected to thermal inactivation. HPV PsV infectivity and morphological integrity was analyzed by cell-based assay and by electron microscopy, respectively. The Holder pasteurization completely inactivated the infectivity of high-risk (types 16 and 18) and low-risk (type 6) HPV both in cell culture medium and in human milk causing PsV particle disassembly. The results presented here indicate that the Holder pasteurization is an efficient procedure to inactivate high-risk and low-risk HPV thus preventing the potential risk of their transmission through human donor milk.

[Immunogenicity of sabin inactivated poliovirus vaccine induced by diphtheria-tetanus-acellular pertussis and Sabin inactivated poliovirus combined vaccine].

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Ma, Yan; Qin, Min; Hu, Hui-Qiong; Ji, Guang; Feng, Ling; Gao, Na; Gu, Jie; Xie, Bing-Feng; He, Ji-Hong; Sun, Ming-Bo

2011-06-01

In order to search the preparation process and optimazing dosage ratio of adsorbed diphtheria-tetanus-acellular pertussis and sabin inactivated poliovirus combined vaccine (DTaP-sIPV), the neutralizing antibody titers of IPV induced by different concentration of DTaP-sIPV were investigated on rats. Two batches of DTaP-sLPV were produced using different concentration of sIPV and the quality control was carried. Together with sabin-IPV and DTaP-wIPV ( boostrix-polio, GSK, Belgium) as control group, the DTaP-sIPV were administrated on three-dose schedule at 0, 1, 2 month on rats. Serum sample were collected 30 days after each dose and neutralizing antibody titers against three types poliovirus were determined using micro-neutralization test. Two batches of prepared DTaP-sIPV and control sLPV were according to the requirement of Chinese Pharmacopoeia (Volume III, 2005 edition) and showed good stability. The seropositivity rates were 100% for sabin inactivated poliovirus antigen in all groups. The GMTs (Geometric mean titers) of neutralizing antibodies against three types poliovirus increased. The prepared DTaP-sIPV was safe, stable and effective and could induced high level neutralizing antibody against poliovirus on rats.

Visible optical radiation generates bactericidal effect applicable for inactivation of health care associated germs demonstrated by inactivation of E. coli and B. subtilis using 405-nm and 460-nm light emitting diodes

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Hönes, Katharina; Stangl, Felix; Sift, Michael; Hessling, Martin

2015-07-01

The Ulm University of Applied Sciences is investigating a technique using visible optical radiation (405 nm and 460 nm) to inactivate health-hazardous bacteria in water. A conceivable application could be point-of-use disinfection implementations in developing countries for safe drinking water supply. Another possible application field could be to provide sterile water in medical institutions like hospitals or dental surgeries where contaminated pipework or long-term disuse often results in higher germ concentrations. Optical radiation for disinfection is presently mostly used in UV wavelength ranges but the possibility of bacterial inactivation with visible light was so far generally disregarded. One of the advantages of visible light is, that instead of mercury arc lamps, light emitting diodes could be used, which are commercially available and therefore cost-efficient concerning the visible light spectrum. Furthermore they inherit a considerable longer life span than UV-C LEDs and are non-hazardous in contrast to mercury arc lamps. Above all there are specific germs, like Bacillus subtilis, which show an inactivation resistance to UV-C wavelengths. Due to the totally different deactivation mechanism even higher disinfection rates are reached, compared to Escherichia coli as a standard laboratory germ. By 460 nm a reduction of three log-levels appeared with Bacillus subtilis and a half log-level with Escherichia coli both at a dose of about 300 J/cm². By the more efficient wavelength of 405 nm four and a half log-levels are reached with Bacillus subtilis and one and a half log-level with Escherichia coli also both at a dose of about 300 J/cm². In addition the employed optical setup, which delivered a homogeneous illumination and skirts the need of a stirring technique to compensate irregularities, was an important improvement compared to previous published setups. Evaluated by optical simulation in ZEMAX® the designed optical element provided proven

Method of inactivation of viral and bacterial blood contaminants

International Nuclear Information System (INIS)

Hackett, R.; Goodrich, R.P.; Van Borssum Waalkes, M.; Wong, V.A.

1992-01-01

A method is provided for inactivating viral and/or bacterial contamination in blood cellular matter, such as erythrocytes and platelets, or protein fractions. The cells or protein fractions are mixed with chemical sensitizers and irradiated with, for example, gamma or X-ray radiation

Some non-thermal microbial inactivation methods in dairy products

International Nuclear Information System (INIS)

Yangilar, F.; Kabil, E.

2013-01-01

During the production of dairy products, some thermal processes such as pasteurization and sterilization are used commonly to inactive microorganisms. But as a result of thermal processes, loss of nutrient and aroma, non-enzymatic browning and organoleptic differentiation especially in dairy products are seen. Because of this, alternative methods are needed to provide microbial inactivation and as major problems are caused by high temperatures, non-thermal processes are focused on. For this purpose, some methods such as high pressure (HP), pulsed light (PL), ultraviolet radiation (UV), supercritical carbon dioxide (SC-CO2) or pulsed electric field (PEF) are used in food. These methods products are processed in ambient temperature and so not only mentioned losses are minimized but also freshness and naturality of products can be preserved. In this work, we will try to be given information about methods of non-thermal microbial inactivation of dairy products. (author) [tr

Polio endgame: the global introduction of inactivated polio vaccine.

Science.gov (United States)

Patel, Manish; Zipursky, Simona; Orenstein, Walt; Garon, Julie; Zaffran, Michel

2015-05-01

In 2013, the World Health Assembly endorsed a plan that calls for the ultimate withdrawal of oral polio vaccines (OPV) from all immunization programs globally. The withdrawal would begin in a phased manner with removal of the type 2 component of OPV in 2016 through a global switch from trivalent OPV to bivalent OPV (containing only types 1 and 3). To mitigate risks associated with immunity gaps after OPV type 2 withdrawal, the WHO Strategic Advisory Group of Experts has recommended that all 126 OPV-only using countries introduce at least one dose of inactivated polio vaccine into routine immunization programs by end-2015, before the trivalent OPV-bivalent OPV switch. The introduction of inactivated polio vaccine would reduce risks of reintroduction of type 2 poliovirus by providing some level of seroprotection, facilitating interruption of transmission if outbreaks occur, and accelerating eradication by boosting immunity to types 1 and 3 polioviruses.

Rabies direct fluorescent antibody test does not inactivate rabies or eastern equine encephalitis viruses.

Science.gov (United States)

Jarvis, Jodie A; Franke, Mary A; Davis, April D

2016-08-01

An examination using the routine rabies direct fluorescent antibody test was performed on rabies or Eastern equine encephalitis positive mammalian brain tissue to assess inactivation of the virus. Neither virus was inactivated with acetone fixation nor the routine test, thus laboratory employees should treat all samples as rabies and when appropriate Eastern equine encephalitis positive throughout the whole procedure. Copyright © 2016 Elsevier B.V. All rights reserved.

Inactivation of infectious bovine rhinotracheitis virus by gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Nonomiya, Takashi; Yamashiro, Tomio; Tsutsumi, Takamasa (Animal Quarantine Service, Yokohama (Japan)); Ito, Hitoshi; Ishigaki, Isao

1990-10-01

Radiation inactivation of Infectious Boivne Rhinotracheitis (IBR) virus was investigated by suspending in a commercial preparation medium (c.p.m.) or IBR antibody free serum and irradiated at room temperature or dry ice frozen condition. Normal pooled serum was also analysed by electrophoresis with cellulose acetate membrane after irradiation at frozen and non-frozen condition. The virus inactivation was determined by MDBK cell line which 50 % tissue culture infectious dose (TCID{sub 50}) was calculated by Behrens Kaerber method. D{sub 10} value at non-frozen condition in serum was obtained as 1.1-1.2 kGy and that in c.p.m. was 1.3-1.4 kGy. On the other hand, D{sub 10} value was increased to 3.4-3.6 kGy in serum and 3.9 kGy in c.p.m. at frozen condition. On the irradiation effect of bovine serum, four peaks of albumin, {alpha}, {beta} and {gamma}-globulin fraction were obtained from non-irradiation and irradiated serum up to 2 kGy at non-frozen condition by electrophoresis. More than 4 kGy irradiation, the peaks of globulin fractions became not clear and at more than 8 kGy, changed to one large peak. On the other hand, these changes of electrophoretic patterns were not observed even at 30 kGy irradiation in frozen condition. From these results, necessary dose was decided as 20-25 kGy at frozen condition for inactivation of IBR virus in serum. (author).

Normal X-inactivation mosaicism in corneas of heterozygous FlnaDilp2/+ female mice--a model of human Filamin A (FLNA diseases

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Douvaras Panagiotis

2012-02-01

Full Text Available Abstract Background Some abnormalities of mouse corneal epithelial maintenance can be identified by the atypical mosaic patterns they produce in X-chromosome inactivation mosaics and chimeras. Human FLNA/+ females, heterozygous for X-linked, filamin A gene (FLNA mutations, display a range of disorders and X-inactivation mosaicism is sometimes quantitatively unbalanced. FlnaDilp2/+ mice, heterozygous for an X-linked filamin A (Flna nonsense mutation have variable eye, skeletal and other abnormalities, but X-inactivation mosaicism has not been investigated. The aim of this study was to determine whether X-inactivation mosaicism in the corneal epithelia of FlnaDilp2/+ mice was affected in any way that might predict abnormal corneal epithelial maintenance. Results X-chromosome inactivation mosaicism was studied in the corneal epithelium and a control tissue (liver of FlnaDilp2/+ and wild-type (WT female X-inactivation mosaics, hemizygous for the X-linked, LacZ reporter H253 transgene, using β-galactosidase histochemical staining. The corneal epithelia of FlnaDilp2/+ and WT X-inactivation mosaics showed similar radial, striped patterns, implying epithelial cell movement was not disrupted in FlnaDilp2/+ corneas. Corrected stripe numbers declined with age overall (but not significantly for either genotype individually, consistent with previous reports suggesting an age-related reduction in stem cell function. Corrected stripe numbers were not reduced in FlnaDilp2/+ compared with WT X-inactivation mosaics and mosaicism was not significantly more unbalanced in the corneal epithelia or livers of FlnaDilp2/+ than wild-type Flna+/+ X-inactivation mosaics. Conclusions Mosaic analysis identified no major effect of the mouse FlnaDilp2 mutation on corneal epithelial maintenance or the balance of X-inactivation mosaicism in the corneal epithelium or liver.

Human milk inactivates pathogens individually, additively, and synergistically.

Science.gov (United States)

Isaacs, Charles E

2005-05-01

Breast-feeding can reduce the incidence and the severity of gastrointestinal and respiratory infections in the suckling neonate by providing additional protective factors to the infant's mucosal surfaces. Human milk provides protection against a broad array of infectious agents through redundancy. Protective factors in milk can target multiple early steps in pathogen replication and target each step with more than one antimicrobial compound. The antimicrobial activity in human milk results from protective factors working not only individually but also additively and synergistically. Lipid-dependent antimicrobial activity in milk results from the additive activity of all antimicrobial lipids and not necessarily the concentration of one particular lipid. Antimicrobial milk lipids and peptides can work synergistically to decrease both the concentrations of individual compounds required for protection and, as importantly, greatly reduce the time needed for pathogen inactivation. The more rapidly pathogens are inactivated the less likely they are to establish an infection. The total antimicrobial protection provided by human milk appears to be far more than can be elucidated by examining protective factors individually.

Bioburden assessment and gamma radiation inactivation patterns in parchment documents

International Nuclear Information System (INIS)

Nunes, Inês; Mesquita, Nuno; Cabo Verde, Sandra; Carolino, Maria Manuela; Portugal, António; Botelho, Maria Luísa

2013-01-01

Parchment documents are part of our cultural heritage and, as historical artifacts that they are, should be preserved. The aim of this study was to validate an appropriate methodology to characterize the bioburden of parchment documents, and to assess the growth and gamma radiation inactivation patterns of the microbiota present in that material. Another goal was to estimate the minimum gamma radiation dose (D min ) to be applied for the decontamination of parchment as an alternative treatment to the current toxic chemical and non-chemical decontamination methods. Two bioburden assessment methodologies were evaluated: the Swab Method (SM) and the Destructive Method (DM). The recovery efficiency of each method was estimated by artificial contamination, using a Cladosporium cladosporioides spore suspension. The parchment samples' microbiota was typified using morphological methods and the fungal isolates were identified by ITS-DNA sequencing. The inactivation pattern was assessed using the DM after exposure to different gamma radiation doses, and using C. cladosporioides as reference. Based on the applied methodology, parchment samples presented bioburden values lower than 5×10 3 CFU/cm 2 for total microbiota, and lower than 10 CFU/cm 2 for fungal propagules. The results suggest no evident inactivation trend for the natural parchment microbiota, especially regarding the fungal community. A minimum gamma radiation dose (D min ) of 5 kGy is proposed for the decontamination treatment of parchment. Determining the minimal decontamination dose in parchment is essential for a correct application of gamma radiation as an alternative decontamination treatment for this type of documents avoiding the toxicity and the degradation promoted by the traditional chemical and non-chemical treatments. - Highlights: • Characterization of the microbial population of parchment documents. • Study the inactivation pattern of parchment microbiota by gamma radiation. • Assessment of

Inactivation of Escherichia coli in a tropical fruit smoothie by a combination of heat and pulsed electric fields.

Science.gov (United States)

Walkling-Ribeiro, M; Noci, F; Cronin, D A; Lyng, J G; Morgan, D J

2008-10-01

Moderate heat in combination with pulsed electric fields (PEF) was investigated as a potential alternative to thermal pasteurization of a tropical fruit smoothie based on pineapple, banana, and coconut milk, inoculated with Escherichia coli K12. The smoothie was heated from 25 degrees C to either 45 or 55 degrees C over 60 s and subsequently cooled to 10 degrees C. PEF was applied at electric field strengths of 24 and 34 kV/cm with specific energy inputs of 350, 500, and 650 kJ/L. Both processing technologies were combined using heat (45 or 55 degrees C) and the most effective set of PEF conditions. Bacterial inactivation was estimated on standard and NaCl-supplemented tryptone soy agar (TSA) to enumerate sublethally injured cells. By increasing the temperature from 45 to 55 degrees C, a higher reduction in E. coli numbers (1 compared with 1.7 log(10) colony forming units {CFU} per milliliter, P field strength was increased during stand-alone PEF treatment from 24 to 34 kV/cm, a greater number of E. coli cells were inactivated (2.8 compared with 4.2 log(10) CFU/mL, P or = 0.05) achieved by thermal pasteurization (72 degrees C, 15 s). A reversed hurdle processing sequence did not affect bacterial inactivation (P> or = 0.05). No differences were observed (P> or = 0.05) between the bacterial counts estimated on nonselective and selective TSA, suggesting that sublethal cell injury did not occur during single PEF treatments or combined heat/PEF treatments.

Polymorphism of antibiotic-inactivating enzyme driven by ecology expands the environmental resistome.

Science.gov (United States)

Kim, Dae-Wi; Thawng, Cung Nawl; Choi, Jung-Hye; Lee, Kihyun; Cha, Chang-Jun

2018-01-01

The environmental resistome has been recognized as the origin and reservoir of antibiotic resistance genes and considered to be dynamic and ever expanding. In this study, a targeted gene sequencing approach revealed that the polymorphic diversity of the aminoglycoside-inactivating enzyme AAC(6')-Ib was ecological niche-specific. AAC(6')-Ib-cr, previously known as a clinical variant, was prevalent in various soils and the intestines of chickens and humans, suggesting that this variant might not have arisen from adaptive mutations in the clinic but instead originated from the environment. Furthermore, ecologically dominant polymorphic variants of AAC(6')-Ib were characterized and found to display different substrate specificities for quinolones and aminoglycosides, conferring the altered resistance spectra. Interestingly, a novel variant with the D179Y substitution showed an extended resistance spectrum to the recently developed fluoroquinolone gemifloxacin. Our results suggest that soil and animal microbiomes could be major reservoirs of antibiotic resistance; polymorphic diversity expands the antibiotic resistome in the environment, resulting in the potential emergence of novel resistance.

Inactivation of Primate Prefrontal Cortex Impairs Auditory and Audiovisual Working Memory.

Science.gov (United States)

Plakke, Bethany; Hwang, Jaewon; Romanski, Lizabeth M

2015-07-01

The prefrontal cortex is associated with cognitive functions that include planning, reasoning, decision-making, working memory, and communication. Neurophysiology and neuropsychology studies have established that dorsolateral prefrontal cortex is essential in spatial working memory while the ventral frontal lobe processes language and communication signals. Single-unit recordings in nonhuman primates has shown that ventral prefrontal (VLPFC) neurons integrate face and vocal information and are active during audiovisual working memory. However, whether VLPFC is essential in remembering face and voice information is unknown. We therefore trained nonhuman primates in an audiovisual working memory paradigm using naturalistic face-vocalization movies as memoranda. We inactivated VLPFC, with reversible cortical cooling, and examined performance when faces, vocalizations or both faces and vocalization had to be remembered. We found that VLPFC inactivation impaired subjects' performance in audiovisual and auditory-alone versions of the task. In contrast, VLPFC inactivation did not disrupt visual working memory. Our studies demonstrate the importance of VLPFC in auditory and audiovisual working memory for social stimuli but suggest a different role for VLPFC in unimodal visual processing. The ventral frontal lobe, or inferior frontal gyrus, plays an important role in audiovisual communication in the human brain. Studies with nonhuman primates have found that neurons within ventral prefrontal cortex (VLPFC) encode both faces and vocalizations and that VLPFC is active when animals need to remember these social stimuli. In the present study, we temporarily inactivated VLPFC by cooling the cortex while nonhuman primates performed a working memory task. This impaired the ability of subjects to remember a face and vocalization pair or just the vocalization alone. Our work highlights the importance of the primate VLPFC in the processing of faces and vocalizations in a manner that

Inactivation of dairy manure-borne pathogens by anaerobic digestion

Science.gov (United States)

Background: Anaerobic digestion of animal manure has the potential to inactivate enteric pathogens, thereby reducing exposures to livestock and humans when the products of digestion are disposed by land-spreading or irrigation or returned to livestock uses such as bedding. Data on digester effectiv...

Modeling high-intensity pulsed electric field inactivation of a lipase from Pseudomonas fluorescens.

Science.gov (United States)

Soliva-Fortuny, R; Bendicho-Porta, S; Martín-Belloso, O

2006-11-01

The inactivation kinetics of a lipase from Pseudomonas fluorescens (EC 3.1.1.3.) were studied in a simulated skim milk ultrafiltrate treated with high-intensity pulsed electric fields. Samples were subjected to electric field intensities ranging from 16.4 to 27.4 kV/cm for up to 314.5 micros, thus achieving a maximum inactivation of 62.1%. The suitability of describing experimental data using mechanistic first-order kinetics and an empirical model based on the Weibull distribution function is discussed. In addition, different mathematical expressions relating the residual activity values to field strength and treatment time are supplied. A first-order fractional conversion model predicted residual activity with good accuracy (A(f) = 1.018). A mechanistic insight of the model kinetics was that experimental values were the consequence of different structural organizations of the enzyme, with uneven resistance to the pulsed electric field treatments. The Weibull model was also useful in predicting the energy density necessary to achieve lipase inactivation.

Inactivation of ultraviolet repair in normal and xeroderma pigmentosum cells by methyl methanesulfonate

International Nuclear Information System (INIS)

Cleaver, J.E.

1982-01-01

Excision repair of ultraviolet damage in the DNA of normal and xeroderma pigmentosum (Groups C, D, and variant) cells was inactivated by exposure of cells to methyl methanesulfonate immediately before irradiation independent of the presence of 0 to 10% fetal calf serum. The inactivation could be represented by a semilog relationship between the amount of repair and methyl methanesulfonate concentration up to approximately 5 mM. The inactivation can be considered to occur as the result of alkylation of a large (about 10(6) daltons) repair enzyme complex, and the dose required to reduce repair to 37% for most cells types was between 4 and 7 mM. No consistent, large difference in sensitivity to methyl methanesulfonate was found in any xeroderma pigmentosum complementation group compared to normal cells, implying that reduced repair in these groups may be caused by small inherited changes in the amino acid composition (i.e., point mutations or small deletions) rather than by losses of major components of the repair enzyme complex

Interaction effect of gamma rays and thermal neutrons on the inactivation of odontoglossum ringspot virus isolated from orchid

International Nuclear Information System (INIS)

Mori, Itsuhiko; Inouye, Narinobu.

1977-01-01

The effect of gamma rays or thermal neutrons and their interaction effects on the inactivation of the infectivity of Odontoglossum ringspot virus (ORSV) in buffered crude sap of the plant tissue were studied. The inactivation effect of gamma ray on ORSV varied in different ionic strength of the phosphate buffer solutions. Borax enhanced this effect. In interaction effect of gamma and neutron irradiation, irradiation orders, that is, n → γ and γ → n, gave different inactivation pattern. (author)

Inactivation of microorganisms for high pressures in the wine industry

International Nuclear Information System (INIS)

Montana B, Jaime Nelson; Ortegon T, Sandra Patricia

2000-01-01

In order to evaluate experimentally the capacity of N 2 and CO 2 under pressure to inactivate wild yeasts, which remain in the Puntalarga vineyard grape, musts were exposed to hyperbaric treatment with these gases. At the end of the pascalization (after 2 hours), CO 2 at 15 degrades Celsius under pressures from 1 to 5 MPa, reached high inactivation percentages of yeast cells (> 90%). Contrary to CO 2 treatment the use of N 2 at 15 degrades Celsius at 4 and 10 MPa failed to exert microbicide effect in a same treatment time. While CO 2 gas with high solubility in water has the potential to reduce microbial loads in musts, N 2 gas with low solubility in water have not effect on the survival of the pathogenic microorganisms in these juices

X Inactivation and Progenitor Cancer Cells

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Ruben Agrelo

2011-04-01

Full Text Available In mammals, silencing of one of the two X chromosomes is necessary to achieve dosage compensation. The 17 kb non-coding RNA called Xist triggers X inactivation. Gene silencing by Xist can only be achieved in certain contexts such as in cells of the early embryo and in certain hematopoietic progenitors where silencing factors are present. Moreover, these epigenetic contexts are maintained in cancer progenitors in which SATB1 has been identified as a factor related to Xist-mediated chromosome silencing.

Safety, immunogenicity and duration of immunity elicited by an inactivated bovine ephemeral fever vaccine.

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Orly Aziz-Boaron

Full Text Available Bovine ephemeral fever (BEF is an economically important viral vector-borne cattle disease. Several live-attenuated, inactivated and recombinant vaccines have been tested, demonstrating varying efficacy. However, to the best of our knowledge, duration of immunity conferred by an inactivated vaccine has never been reported. In the last decade, Israel has faced an increasing number of BEF outbreaks. The need for an effective vaccine compatible with strains circulating in the Middle East region led to the development of a MONTANIDE™ ISA 206 VG (water-in-oil-in-water, inactivated vaccine based on a local strain. We tested the safety, immunogenicity and duration of immunity conferred by this vaccine. The induced neutralizing antibody (NA response was followed for 493 days in 40 cows vaccinated by different protocols. The vaccine did not cause adverse reactions or a decrease in milk production. All cows [except 2 (6.7% which did not respond to vaccination] showed a significant rise in NA titer of up to 1:256 following the second, third or fourth booster vaccination. Neutralizing antibody levels declined gradually to 1:16 up to 120 days post vaccination. This decline continued in cows vaccinated only twice, whereas cows vaccinated 3 or 4 times showed stable titers of approximately 1:16 for up to 267 days post vaccination. At least three vaccinations with the inactivated BEF vaccine were needed to confer long-lasting immunity. These results may have significant implications for the choice of vaccination protocol with inactivated BEF vaccines. Complementary challenge data should however be added to the above results in order to determine what is the minimal NA response conferring protection from clinical disease.

Intranasal Immunization with Pressure Inactivated Avian Influenza Elicits Cellular and Humoral Responses in Mice.

Directory of Open Access Journals (Sweden)

Shana P C Barroso

Full Text Available Influenza viruses pose a serious global health threat, particularly in light of newly emerging strains, such as the avian influenza H5N1 and H7N9 viruses. Vaccination remains the primary method for preventing acquiring influenza or for avoiding developing serious complications related to the disease. Vaccinations based on inactivated split virus vaccines or on chemically inactivated whole virus have some important drawbacks, including changes in the immunogenic properties of the virus. To induce a greater mucosal immune response, intranasally administered vaccines are highly desired as they not only prevent disease but can also block the infection at its primary site. To avoid these drawbacks, hydrostatic pressure has been used as a potential method for viral inactivation and vaccine production. In this study, we show that hydrostatic pressure inactivates the avian influenza A H3N8 virus, while still maintaining hemagglutinin and neuraminidase functionalities. Challenged vaccinated animals showed no disease signs (ruffled fur, lethargy, weight loss, and huddling. Similarly, these animals showed less Evans Blue dye leakage and lower cell counts in their bronchoalveolar lavage fluid compared with the challenged non-vaccinated group. We found that the whole inactivated particles were capable of generating a neutralizing antibody response in serum, and IgA was also found in nasal mucosa and feces. After the vaccination and challenge we observed Th1/Th2 cytokine secretion with a prevalence of IFN-γ. Our data indicate that the animals present a satisfactory immune response after vaccination and are protected against infection. Our results may pave the way for the development of a novel pressure-based vaccine against influenza virus.

Key tumor suppressor genes inactivated by "greater promoter" methylation and somatic mutations in head and neck cancer

NARCIS (Netherlands)

Guerrero-Preston, Rafael; Michailidi, Christina; Marchionni, Luigi; Pickering, Curtis R.; Frederick, Mitchell J.; Myers, Jeffrey N.; Yegnasubramanian, Srinivasan; Hadar, Tal; Noordhuis, Maartje G.; Zizkova, Veronika; Fertig, Elana; Agrawal, Nishant; Westra, William; Koch, Wayne; Califano, Joseph; Velculescu, Victor E.; Sidransky, David

Tumor suppressor genes (TSGs) are commonly inactivated by somatic mutation and/or promoter methylation; yet, recent high-throughput genomic studies have not identified key TSGs inactivated by both mechanisms. We pursued an integrated molecular analysis based on methylation binding domain sequencing

Oxygen-independent inactivation of Haemophilus influenzae transforming DNA by monochromatic radiation: action spectrum, effect of histidine and repair

Energy Technology Data Exchange (ETDEWEB)

Cabrera-Juarez, E; Setlow, J K; Swenson, P A; Peak, M J

1976-01-01

The action spectrum for the oxygen-independent inactivation of native transforming DNA from Haemophilus influenzae with near-uv radiation revealed a shoulder beginning at 334 and extending to 460 nm. The presence of 0.2 M histidine during irradiation produced a small increase in inactivation at 254, 290 and 313 nm, a large increase at 334 nm and a decrease in inactivation at 365, 405, and 460 nm. Photoreactivation did not reverse the DNA damage produced at pH 7.0 at 334, 365, 405 and 460 nm, but did reactivate the DNA after irradiation at 254, 290 and 313 nm. The inactivation of DNA irradiated at 254, 290 and 313 nm was considerably greater when the transforming ability was assayed in an excision-defective mutant compared with the wild type, although DNA irradiated at 334, 365, 405 and 460 nm showed smaller differences. These results suggest that the oxygen-independent inactivation of H. influenzae DNA at pH 7 by irradiation at 334, 365, 405 and 460 nm is caused by lesions other than pyrimidine dimers.

Inactivated yellow fever 17D vaccine: development and nonclinical safety, immunogenicity and protective activity.

Science.gov (United States)

Monath, Thomas P; Lee, Cynthia K; Julander, Justin G; Brown, Alicja; Beasley, David W; Watts, Douglas M; Hayman, Edward; Guertin, Patrick; Makowiecki, Joseph; Crowell, Joseph; Levesque, Philip; Bowick, Gavin C; Morin, Merribeth; Fowler, Elizabeth; Trent, Dennis W

2010-05-14

In the last 10 years new concerns have arisen about safety of the live, attenuated yellow fever (YF) 17D vaccine, in particular viscerotropic adverse events, which have a case-fatality rate of 64%. A non-replicating cell culture-based vaccine would not cause these adverse events, and potentially could be used in persons with precautions or contraindications to use of the live vaccine, including age 60 years, egg allergy, immune suppression, and pregnancy. We developed a whole virion vaccine from the 17D strain inactivated with beta-propiolactone, and adsorbed to aluminum hydroxide. The inactivated vaccine was highly immunogenic in mice, hamsters, and cynomolgus macaques. After a single dose in hamsters and macaques, neutralizing antibody titers were similar to those elicited by the live 17D vaccine (YF-VAX, Sanofi Pasteur). After two doses of inactivated vaccine, neutralizing antibody titers in hamsters were significantly higher than after a single dose of YF-VAX [geometric mean titer (GMT) 20,480 vs. 1940, respectively (Pvaccine or a single dose of YF-VAX were fully protected against hepatitis, viremia, weight loss and death after challenge with YF virus (Jimenez strain). A clinical trial of the inactivated vaccine (XRX-001) has been initiated. Copyright 2010 Elsevier Ltd. All rights reserved.

Procaine rapidly inactivates acetylcholine receptors from Torpedo and competes with agonist for inhibition sites

International Nuclear Information System (INIS)

Forman, S.A.; Miller, K.W.

1989-01-01

The relationship between the high-affinity procaine channel inhibition site and the agonist self-inhibition site on acetylcholine receptors (AChRs) from Torpedo electroplaque was investigated by using rapid 86 Rb + quenched-flux assays at 4 degree C in native AChR-rich vesicles on which 50-60% of ACh activation sites were blocked with α-bungarotoxin (α-BTX). In the presence of channel-activating acetylcholine (ACh) concentrations alone, AChR undergoes one phase of inactivation in under a second. Addition of procaine produces two-phase inactivation similar to that seen with self-inhibiting ACh concentrations rapid inactivation complete in 30-75 ms is followed by fast desensitization at the same k d observed without procaine. The dependence of k r on [procaine] is consistent with a bimolecular association between procaine and its AChR site. Inhibition of AChR function by mixtures of procaine plus self-inhibiting concentrations of ACh or suberyldicholine was studied by reducing the level of α-BTX block in vesicles. The data support a mechanism where procaine binds preferentially to the open-channel AChR state, since no procaine-induced inactivation is observed without agonist and k r 's dependence on [ACh] in channel-activating range closely parallels that of 86 Rb + flux response to ACh

Antigen sparing with adjuvanted inactivated polio vaccine based on Sabin strains.

Science.gov (United States)

Westdijk, Janny; Koedam, Patrick; Barro, Mario; Steil, Benjamin P; Collin, Nicolas; Vedvick, Thomas S; Bakker, Wilfried A M; van der Ley, Peter; Kersten, Gideon

2013-02-18

Six different adjuvants, each in combination with inactivated polio vaccine (IPV) produced with attenuated Sabin strains (sIPV), were evaluated for their ability to enhance virus neutralizing antibody titres (VNTs) in the rat potency model. The increase of VNTs was on average 3-, 15-, 24-fold with adjuvants after one immunization (serotypes 1, 2, and 3, respectively). Also after a boost immunization the VNTs of adjuvanted sIPV were on average another 7-20-27 times higher than after two inoculations of sIPV without adjuvant. The results indicate that it is feasible to increase the potency of inactivated polio vaccines by using adjuvants. Copyright © 2013 Elsevier Ltd. All rights reserved.

Microbial Inactivation in the Liquid Phase Induced by Multigas Plasma Jet.

Directory of Open Access Journals (Sweden)

Toshihiro Takamatsu

Full Text Available Various gas atmospheric nonthermal plasmas were generated using a multigas plasma jet to treat microbial suspensions. Results indicated that carbon dioxide and nitrogen plasma had high sterilization effects. Carbon dioxide plasma, which generated the greatest amount of singlet oxygen than other gas plasmas, killed general bacteria and some fungi. On the other hand, nitrogen plasma, which generated the largest amount of OH radical, killed ≥ 6 log of 11 species of microorganisms, including general bacteria, fungi, acid-fast bacteria, spores, and viruses in 1-15 min. To identify reactive species responsible for bacterial inactivation, antioxidants were added to bacterial suspensions, which revealed that singlet oxygen and OH radicals had greatest inactivation effects.

Inactivation of lipoxygenase in whole soy flour suspension by ultrasonic cavitation

International Nuclear Information System (INIS)

Thakur, B.R.; Nelson, P.E.

1997-01-01

Use of ultrasound for lipoxygenase inactivation in whole soy flour suspension was studied. Inactivation of the enzyme was influenced by the time of exposure, pH, and the amplitude of ultrasound. Exposure to cavitating 20 kHz ultrasound for 3 h at pH5.0 had no effect on the activity of the enzyme. However, under similar conditions, the activity decreased by 70-85% when pH was lowered to 5.0 and 4.0, respectively. Lipoxygenase activity also decreased with increase in frequency of the ultrasound waves when pH was 5.0; above pH 5.0, increase in frequency did not affect the enzyme activity after an exposure of 1 h

Neutralization of Aerosolized Bio-Agents by Filled Nanocomposite Materials through Thermal and Chemical Inactivation Mechanisms

Science.gov (United States)

2016-06-01

Bio -agents by Filled Nanocomposite Materials through Thermal and Chemical Inactivation Mechanisms Distribution Statement A. Approved for public...of Cincinnati Project Title: Neutralization of Aerosolized Bio -agents by Filled Nanocomposite Materials through Thermal and Chemical Inactivation...fire ball, where they will not effectively interact with any viable bio -aerosol. 1.1.4. Conclusions Cryo-milling is necessary to achieve a

Tumor suppressor genes that escape from X-inactivation contribute to cancer sex bias

OpenAIRE

Dunford, Andrew; Weinstock, David M.; Savova, Virginia; Schumacher, Steven E.; Cleary, John P.; Yoda, Akinori; Sullivan, Timothy J.; Hess, Julian M.; Gimelbrant, Alexander A.; Beroukhim, Rameen; Lawrence, Michael S.; Getz, Gad; Lane, Andrew A.

2016-01-01

There is a striking and unexplained male predominance across many cancer types. A subset of X chromosome (chrX) genes can escape X-inactivation, which would protect females from complete functional loss by a single mutation. To identify putative “Escape from X-Inactivation Tumor Suppressor” (EXITS) genes, we compared somatic alterations from >4100 cancers across 21 tumor types for sex bias. Six of 783 non-pseudoautosomal region (PAR) chrX genes (ATRX, CNKSR2, DDX3X, KDM5C, KDM6A, and MAGEC3) ...

Atmospheric plasma processes for microbial inactivation: food applications and stress response in Listeria monocytogenes

OpenAIRE

Gozzi, Giorgia

2015-01-01

This PhD thesis is focused on cold atmospheric plasma treatments (GP) for microbial inactivation in food applications. In fact GP represents a promising emerging technology alternative to the traditional methods for the decontamination of foods. The objectives of this work were to evaluate: - the effects of GP treatments on microbial inactivation in model systems and in real foods; - the stress response in L. monocytogenes following exposure to different GP treatments. As far as t...

Sequential and Simultaneous Applications of UV and Chlorine for Adenovirus Inactivation.

Science.gov (United States)

Rattanakul, Surapong; Oguma, Kumiko; Takizawa, Satoshi

2015-09-01

Adenoviruses are water-borne human pathogens with high resistance to UV disinfection. Combination of UV treatment and chlorination could be an effective approach to deal with adenoviruses. In this study, human adenovirus 5 (HAdV-5) was challenged in a bench-scale experiment by separate applications of UV or chlorine and by combined applications of UV and chlorine in either a sequential or simultaneous manner. The treated samples were then propagated in human lung carcinoma epithelial cells to quantify the log inactivation of HAdV-5. When the processes were separate, a fluence of 100 mJ/cm(2) and a CT value of 0.02 mg min/L were required to achieve 2 log inactivation of HAdV-5 by UV disinfection and chlorination, respectively. Interestingly, synergistic effects on the HAdV-5 inactivation rates were found in the sequential process of chlorine followed by UV (Cl2-UV) (p simultaneous application of UV/Cl2. This implies that a pretreatment with chlorine may increase the sensitivity of the virus to the subsequent UV disinfection. In conclusion, this study suggests that the combined application of UV and chlorine could be an effective measure against adenoviruses as a multi-barrier approach in water disinfection.

Eslicarbazepine and the enhancement of slow inactivation of voltage-gated sodium channels: a comparison with carbamazepine, oxcarbazepine and lacosamide.

Science.gov (United States)

Hebeisen, Simon; Pires, Nuno; Loureiro, Ana I; Bonifácio, Maria João; Palma, Nuno; Whyment, Andrew; Spanswick, David; Soares-da-Silva, Patrício

2015-02-01

This study aimed at evaluating the effects of eslicarbazepine, carbamazepine (CBZ), oxcarbazepine (OXC) and lacosamide (LCM) on the fast and slow inactivated states of voltage-gated sodium channels (VGSC). The anti-epileptiform activity was evaluated in mouse isolated hippocampal slices. The anticonvulsant effects were evaluated in MES and the 6-Hz psychomotor tests. The whole-cell patch-clamp technique was used to investigate the effects of eslicarbazepine, CBZ, OXC and LCM on sodium channels endogenously expressed in N1E-115 mouse neuroblastoma cells. CBZ and eslicarbazepine exhibit similar concentration dependent suppression of epileptiform activity in hippocampal slices. In N1E-115 mouse neuroblastoma cells, at a concentration of 250 μM, the voltage dependence of the fast inactivation was not influenced by eslicarbazepine, whereas LCM, CBZ and OXC shifted the V0.5 value (mV) by -4.8, -12.0 and -16.6, respectively. Eslicarbazepine- and LCM-treated fast-inactivated channels recovered similarly to control conditions, whereas CBZ- and OXC-treated channels required longer pulses to recover. CBZ, eslicarbazepine and LCM shifted the voltage dependence of the slow inactivation (V0.5, mV) by -4.6, -31.2 and -53.3, respectively. For eslicarbazepine, LCM, CBZ and OXC, the affinity to the slow inactivated state was 5.9, 10.4, 1.7 and 1.8 times higher than to the channels in the resting state, respectively. In conclusion, eslicarbazepine did not share with CBZ and OXC the ability to alter fast inactivation of VGSC. Both eslicarbazepine and LCM reduce VGSC availability through enhancement of slow inactivation, but LCM demonstrated higher interaction with VGSC in the resting state and with fast inactivation gating. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cellular inactivation of nitric oxide induces p53-dependent ...

African Journals Online (AJOL)

Tropical Journal of Pharmaceutical Research August 2016; 15 (8): 1595-1603 ... Cellular inactivation of nitric oxide induces p53-dependent apoptosis in ... apoptosis induced by a selective iNOS inhibitor, N-[(3-aminomethyl) benzyl] acetamidine (1400W), .... and nitrate. ... Nitrite production was measured in culture media.

Effect of using heat-inactivated serum with the Abbott human T-cell lymphotropic virus type III antibody test.

OpenAIRE

Jungkind, D L; DiRenzo, S A; Young, S J

1986-01-01

The Abbott enzyme immunoassay (Abbott Laboratories, North Chicago, Ill.) for human T-cell lymphotropic virus type III (HTLV-III) antibody was evaluated to determine the effect of using heat-inactivated (56 degrees C for 30 min) serum as the sample. Each of 58 nonreactive serum samples gave a higher A492 value when tested after heat inactivation. Ten of the samples became reactive after heating. Heat-inactivated serum should not be used in the current Abbott HTLV-III antibody test, because thi...

Nitroxide radicals as research tools: Elucidating the kinetics and mechanisms of catalase-like and "suicide inactivation" of metmyoglobin.

Science.gov (United States)

Samuni, Uri; Czapski, Gideon; Goldstein, Sara

2016-07-01

Metmyoglobin (MbFe(III)) reaction with H(2)O(2) has been a subject of study over many years. H(2)O(2) alone promotes heme destruction frequently denoted "suicide inactivation," yet the mechanism underlying H(2)O(2) dismutation associated with MbFe(III) inactivation remains obscure. MbFe(III) reaction with excess H(2)O(2) in the absence and presence of the nitroxide was studied at pH 5.3-8.1 and 25°C by direct determination of reaction rate constants using rapid-mixing stopped-flow technique, by following H(2)O(2) depletion, O(2) evolution, spectral changes of the heme protein, and the fate of the nitroxide by EPR spectroscopy. The rates of both H(2)O(2) dismutation and heme inactivation processes depend on [MbFe(III)], [H(2)O(2)] and pH. Yet the inactivation stoichiometry is independent of these variables and each MbFe(III) molecule catalyzes the dismutation of 50±10 H(2)O(2) molecules until it is inactivated. The nitroxide catalytically enhances the catalase-like activity of MbFe(III) while protecting the heme against inactivation. The rate-determining step in the absence and presence of the nitroxide is the reduction of MbFe(IV)O by H(2)O(2) and by nitroxide, respectively. The nitroxide effects on H(2)O(2) dismutation catalyzed by MbFe(III) demonstrate that MbFe(IV)O reduction by H(2)O(2) is the rate-determining step of this process. The proposed mechanism, which adequately fits the pro-catalytic and protective effects of the nitroxide, implies the intermediacy of a compound I-H(2)O(2) adduct, which decomposes to a MbFe(IV)O and an inactivated heme at a ratio of 25:1. The effects of nitroxides are instrumental in elucidating the mechanism underlying the catalysis and inactivation routes of heme proteins. Copyright © 2016 Elsevier B.V. All rights reserved.

Inactivation Methods of Trypsin Inhibitor in Legumes: A Review.

Science.gov (United States)

Avilés-Gaxiola, Sara; Chuck-Hernández, Cristina; Serna Saldívar, Sergio O

2018-01-01

Seed legumes have played a major role as a crop worldwide, being cultivated on about 12% to 15% of Earth's arable land; nevertheless, their use is limited by, among other things, the presence of several antinutritional factors (ANFs - naturally occurring metabolites that the plant produces to protect itself from pest attacks.) Trypsin inhibitors (TIs) are one of the most relevant ANFs because they reduce digestion and absorption of dietary proteins. Several methods have been developed in order to inactivate TIs, and of these, thermal treatments are the most commonly used. They cause loss of nutrients, affect functional properties, and require high amounts of energy. Given the above, new processes have emerged to improve the nutritional quality of legumes while trying to solve the problems caused by the use of thermal treatments. This review examines and discusses the methods developed by researchers to inactivate TI present in legumes and their effects over nutritional and functional properties. © 2017 Institute of Food Technologists®.

Physicochemical stability and inactivation of human and simian rotaviruses

International Nuclear Information System (INIS)

Meng, Z.D.; Birch, C.; Heath, R.; Gust, I.

1987-01-01

The effects of various physical and chemical treatments on the stability of a human serotype 1 rotavirus and simian agent 11 (SA11) were compared by using a fluorescence focus assay. The infectivity of both strains was retained after storage at room temperature for 14 days, 4 degree C for 22 days, and -20 degree C for 32 days; lyophilization; and treatment at pH 3 to 11. Both viruses were inactivated at pH 12, as was the human virus at pH 2, although this pH resulted in only partial inactivation of SA11. The human virus also appeared to be more sensitive than SA11 to the action of ether and chloroform. The infectivity of both viruses was lost after UV irradiation for 15 min and after treatment with 8% formaldehyde for 5 min, 70% (vol/vol) ethanol for 30 min, and 2% lysol, 2% phenol, and 1% H 2 O 2 for 1 h each

Physicochemical stability and inactivation of human and simian rotaviruses

Energy Technology Data Exchange (ETDEWEB)

Meng, Z.D.; Birch, C.; Heath, R.; Gust, I.

1987-04-01

The effects of various physical and chemical treatments on the stability of a human serotype 1 rotavirus and simian agent 11 (SA11) were compared by using a fluorescence focus assay. The infectivity of both strains was retained after storage at room temperature for 14 days, 4 degree C for 22 days, and -20 degree C for 32 days; lyophilization; and treatment at pH 3 to 11. Both viruses were inactivated at pH 12, as was the human virus at pH 2, although this pH resulted in only partial inactivation of SA11. The human virus also appeared to be more sensitive than SA11 to the action of ether and chloroform. The infectivity of both viruses was lost after UV irradiation for 15 min and after treatment with 8% formaldehyde for 5 min, 70% (vol/vol) ethanol for 30 min, and 2% lysol, 2% phenol, and 1% H/sub 2/O/sub 2/ for 1 h each.

Short communication: effect of homogenization on heat inactivation of Mycobacterium avium subspecies paratuberculosis in milk.

Science.gov (United States)

Hammer, P; Kiesner, C; Walte, H-G C

2014-01-01

Mycobacterium avium ssp. paratuberculosis (MAP) can be present in cow milk and low numbers may survive high-temperature, short-time (HTST) pasteurization. Although HTST treatment leads to inactivation of at least 5 log10 cycles, it might become necessary to enhance the efficacy of HTST by additional treatments such as homogenization if the debate about the role of MAP in Crohn's disease of humans concludes that MAP is a zoonotic agent. This study aimed to determine whether disrupting the clumps of MAP in milk by homogenization during the heat treatment process would enhance the inactivation of MAP. We used HTST pasteurization in a continuous-flow pilot-plant pasteurizer and evaluated the effect of upstream, downstream, and in-hold homogenization on inactivation of MAP. Reduction of MAP at 72°C with a holding time of 28s was between 3.7 and 6.9 log10 cycles, with an overall mean of 5.5 log10 cycles. None of the 3 homogenization modes applied showed a statistically significant additional effect on the inactivation of MAP during HTST treatment. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Role of polyols in thermal inactivation of shark ornithine transcarbamoylase

Czech Academy of Sciences Publication Activity Database

Bellocco, E.; Lagana, G.; Barreca, D.; Ficarra, S.; Tellone, E.; Magazu, S.; Branca, C.; Kotyk, Arnošt; Galtieri, A.; Leuzzi, U.

2005-01-01

Roč. 54, č. 4 (2005), s. 395-402 ISSN 0862-8408 Institutional research plan: CEZ:AV0Z5011922 Keywords : ornithine transcarbamoylase * thermal inactivation * shark enzyme Subject RIV: CE - Biochemistry Impact factor: 1.806, year: 2005