Interaction with Deoxyribonucleic Acid and Determination of Orientin in Lophatherum gracile Brongn by High-Performance Liquid Chromatography with Amperometric Detection

International Nuclear Information System (INIS)

Wang, Fang; Yan, Fangfang; Long, Yuling; Wang, Lili; Chen, Zilin

2015-01-01

The mechanisms of the electrochemical oxidation of orientin and its interaction with deoxyribonucleic acid have been investigated using glassy carbon electrode. The electrochemical response of orientin is due to oxidation of phenolic hydroxyl groups on orientin. The whole process is controlled by the adsorption step and concerned 4 electrons and 4 protons. Negative shift of potential and decrease of peak current for electrochemical oxidation of orientin can be observed at bare glassy carbon electrode and deoxyribonucleic acid modified electrode in 0.05 M Na_2HPO_4-KH_2PO_4 (pH 7.48), confirming the dominant electrostatic interaction between orientin and deoxyribonucleic acid. Moreover, a reliable and sensitive method of reversed-phase high-performance liquid chromatography-electrochemical detection has been developed for simultaneous determination of the isomer pair orientin/isoorientin. Chromatographic separation was carried out on a reversed-phase C_1_8 column and a mobile phase comprised of acetonitrile and acetate (0.5%, pH 2.97) by amperometric detection with a glassy carbon electrode at the working potential of +1.00 V. The method was validated for linearity, accuracy, precision, and limit of detection. Under the optimized conditions, linear regression analysis for the calibration curve showed a good linear relationship between peak area and their concentrations in the linear range of 89.2 nM to 59.5 μM for orientin with detection limit of 14.9 nM and 78.0 nM to 52.0 μM for isoorientin with a detection limit of 13.0 nM, respectively. Compared to the method using ultraviolet detection, the detection limits are greatly lowered. Finally, the proposed method has been successfully applied to the determination of orientin and isoorientin in Lophatherum gracile Brongn.

Role of deoxyribonucleic acid polymerases and deoxyribonucleic acid ligase in x-ray-induced repair synthesis in toluene-treated Escherichia coli K-12

International Nuclear Information System (INIS)

Billen, D.; Hellermann, G.R.

1976-01-01

Toluene-treated Escherichia coli mutants have been used to study the roles of deoxyribonucleic acid (DNA) polymerases I, II, and III, and of DNA ligase in repair synthesis and strand rejoining following X-irradiation. In cells possessing all three DNA polymerases, both a greater amount of repair synthesis (''exaggerated'' repair synthesis) and failure of ligation are observed when DNA ligase activity is inhibited. In a mutant lacking the polymerizing activity of DNA polymerase I, exaggerated repair synthesis is not observed, and strand rejoining does not occur even if DNA ligase is fully activated. In a mutant possessing the polymerizing activity of DNA polymerase I but lacking its 5' → 3' exonuclease activity, exaggerated repair synthesis is minimal. After irradiation, DNA polymerases II and III are capable of carrying out an adenosine 5'-triphosphate-dependent repair synthesis, but rejoining of strand breaks does not occur and exaggerated synthesis is not seen whether DNA ligase is active or not. These results suggest that DNA polymerase I and DNA ligase act together to limit repair synthesis after X irradiation and that both are necessary in toluene-treated cells for strand rejoining. DNA polymerases II and III apparently cannot complete chain elongation and gap filling, and therefore repair carried out by these enzymes does not respond to ligase action

Binding of T4 endonuclease V to deoxyribonucleic acid irradiated with ultraviolet light

International Nuclear Information System (INIS)

Seawell, P.C.; Simon, T.J.; Ganesan, A.K.

1980-01-01

Endonuclease V of bacteriophage T4 binds to uv-irradiated deoxyribonucleic acid (DNA) but not to unirradiated DNA. We have developed an assay to detect this binding, based on the retention of enzyme - DNA complexes on nitrocellulose filters. The amount of complex retained, ascertained by using radioactive DNA, is a measure of T4 endonuclease V activity. From our data we conclude that (1) T4 endonuclease V binds to uv-irradiated DNA but not to DNA that has been previously incised by the endonuclease, (2) equilibrium between the free and complexed form of the enzyme is attained under our reaction conditions, (3) dissociation of enzyme - DNA complexes is retarded by sodium cyanide, and (4) retention of enzyme - DNA complexes on nitrocellulose filters is enhanced by high concentrations of saline-citrate

Deoxyribonucleic acid repair in Escherichia coli mutants deficient in the 5'----3' exonuclease activity of deoxyribonucleic acid polymerase I and exonuclease VII

International Nuclear Information System (INIS)

Chase, J.W.; Masker, W.E.

1977-01-01

A series of Escherichia coli strains deficient in the 5'----3' exonuclease activity associated with deoxyribonucleic acid (DNA) polymerase I (exonuclease VI) and exonuclease VII has been constructed. Both of these enzymes are capable of pyrimidine dimer excision in vitro. These strains were examined for conditional lethality, sensitivity to ultraviolet (UV) and X-irradiation, postirradiation DNA degradation, and ability to excise pyrimidine dimers. It was found that strains deficient in both exonuclease VI (polAex-) and exonuclease VII (xseA-) are significantly reduced in their ability to survive incubation at elevated temperature (43 degrees C) beyond the reduction previously observed for the polAex single mutants. The UV and X-ray sensitivity of the exonuclease VI-deficient strains was not increased by the addition of the xseA7 mutation. Mutants deficient in both enzymes are about as efficient as wild-type strains at excising dimers produced by up to 40 J/m2 UV. At higher doses strains containing only polAex- mutations show reduced ability to excise dimers; however, the interpretation of dimer excision data at these doses is complicated by extreme postirradiation DNA degradation in these strains. The additional deficiency in the polAex xseA7 double-mutant strains has no significant effect on either postirradiation DNA degradation or the apparent deficiency in dimer excision at high UV doses observed in polAex single mutants

Integrity of nuclear genomic deoxyribonucleic acid in cooked meat: Implications for food traceability.

Science.gov (United States)

Aslan, O; Hamill, R M; Sweeney, T; Reardon, W; Mullen, A M

2009-01-01

It is essential to isolate high-quality DNA from muscle tissue for PCR-based applications in traceability of animal origin. We wished to examine the impact of cooking meat to a range of core temperatures on the quality and quantity of subsequently isolated genomic (specifically, nuclear) DNA. Triplicate steak samples were cooked in a water bath (100 degrees C) until their final internal temperature was 75, 80, 85, 90, 95, or 100 degrees C, and DNA was extracted. Deoxyribonucleic acid quantity was significantly reduced in cooked meat samples compared with raw (6.5 vs. 56.6 ng/microL; P 800 bp) were observed only when using DNA from raw meat and steak cooked to lower core temperatures. Small amplicons (food authentication, it is less abundant, and results suggest that analyses should be designed to use small amplicon sizes for meat cooked to high core temperatures.

Study of the interaction of enzyme Heparanase 1 (HPSE1) active with deoxyribonucleic acids

International Nuclear Information System (INIS)

Cid, Gisele da Silva

2016-01-01

The human heparanase 1 (HPSE 1) is a protein with multiple functions and has emerged as a promising therapeutic target in the context of antitumor therapy. This fact is due to its clinical relevance in the tumor development and progression, as determined by their enzymatic ability to degrade heparan sulfate (HS), the main constituent of the extracellular matrix, providing a tumor microenvironment to tumor dissemination. In addition, this protein plays a significant role in the increase of tumor cells migration ionizing radiation dose delivery in radiotherapy from the increase in the expression levels of HPSE1. In order to evaluate in more detail the functions of active HPSE1, it has been proposed to characterize the interaction of human heparanase protein 1 with deoxyribonucleic acids. Our results are original and point to a new function of HPSE1 of the endonuclease type. (author)

High mobility organic field-effect transistor based on water-soluble deoxyribonucleic acid via spray coating

Energy Technology Data Exchange (ETDEWEB)

Shi, Wei; Han, Shijiao; Huang, Wei; Yu, Junsheng, E-mail: jsyu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

2015-01-26

High mobility organic field-effect transistors (OFETs) by inserting water-soluble deoxyribonucleic acid (DNA) buffer layer between electrodes and pentacene film through spray coating process were fabricated. Compared with the OFETs incorporated with DNA in the conventional organic solvents of ethanol and methanol: water mixture, the water-soluble DNA based OFET exhibited an over four folds enhancement of field-effect mobility from 0.035 to 0.153 cm{sup 2}/Vs. By characterizing the surface morphology and the crystalline structure of pentacene active layer through atomic force microscope and X-ray diffraction, it was found that the adoption of water solvent in DNA solution, which played a key role in enhancing the field-effect mobility, was ascribed to both the elimination of the irreversible organic solvent-induced bulk-like phase transition of pentacene film and the diminution of a majority of charge trapping at interfaces in OFETs.

Bacterial cells with improved tolerance to isobutyric acid

DEFF Research Database (Denmark)

2017-01-01

Bacterial cells genetically modified to improve their tolerance to certain commodity chemicals, such as isobutyric acid and related compounds, and methods of preparing and using such bacterial cells for production of isobutyric acid and related compounds.......Bacterial cells genetically modified to improve their tolerance to certain commodity chemicals, such as isobutyric acid and related compounds, and methods of preparing and using such bacterial cells for production of isobutyric acid and related compounds....

No activation of new initiation points for deoxyribonucleic acid replication in BALB/c 3T3 cells transformed by Kirsten sarcoma virus

International Nuclear Information System (INIS)

Oppenheim, A.; Horowitz, A.T.

1981-01-01

BALB/c 3T3 cells were transformed by Kirsten sarcoma virus, and five clones were isolated in soft agar. Average replicon sizes of the transformed cell lines were stimated by the method of fiber-autoradiography and found to be the same size as the nontransformed 3T3 cells, analyzed in parallel. The results indicate that, unlike simian virus 40 and Epstein-Barr virus, Kirsten sarcoma virus does not activate new initiation points for cellular deoxyribonucleic acid replication in murine sarcome virus-transformed BALB/c 3T3 cells

Bacterial fatty acid metabolism in modern antibiotic discovery.

Science.gov (United States)

Yao, Jiangwei; Rock, Charles O

2017-11-01

Bacterial fatty acid synthesis is essential for many pathogens and different from the mammalian counterpart. These features make bacterial fatty acid synthesis a desirable target for antibiotic discovery. The structural divergence of the conserved enzymes and the presence of different isozymes catalyzing the same reactions in the pathway make bacterial fatty acid synthesis a narrow spectrum target rather than the traditional broad spectrum target. Furthermore, bacterial fatty acid synthesis inhibitors are single-targeting, rather than multi-targeting like traditional monotherapeutic, broad-spectrum antibiotics. The single-targeting nature of bacterial fatty acid synthesis inhibitors makes overcoming fast-developing, target-based resistance a necessary consideration for antibiotic development. Target-based resistance can be overcome through multi-targeting inhibitors, a cocktail of single-targeting inhibitors, or by making the single targeting inhibitor sufficiently high affinity through a pathogen selective approach such that target-based mutants are still susceptible to therapeutic concentrations of drug. Many of the pathogens requiring new antibiotic treatment options encode for essential bacterial fatty acid synthesis enzymes. This review will evaluate the most promising targets in bacterial fatty acid metabolism for antibiotic therapeutics development and review the potential and challenges in advancing each of these targets to the clinic and circumventing target-based resistance. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop. Copyright © 2016 Elsevier B.V. All rights reserved.

Ability of Bacillus subtilis protoplasts to repair irradiated bacteriophage deoxyribonucleic acid via acquired and natural enzymatic systems

International Nuclear Information System (INIS)

Yasbin, R.E.; Andersen, B.J.; Sutherland, B.M.

1981-01-01

A novel form of enzyme therapy was achieved by utilizing protoplasts of Bacillus subtilis. Photoreactivating enzyme of Escherichia coli was successfully inserted into the protoplasts of B. subtilis treated with polyethylene glycol. This enzyme was used to photoreactivate ultraviolet-damaged bacteriophage deoxyribonucleic acid (DNA). Furthermore, in polyethylene glycol-treated protoplasts, ultraviolet-irradiated transfecting bacteriophage DNA was shown to be a functional substrate for the host DNA excision repair system. Previous results (R.E. Yasbin, J.D. Fernwalt, and P.I. Fields, J. Bacteriol.; 137: 391-396) showed that ultraviolet-irradiated bacteriophage DNA could not be repaired via the excision repair system of competent cells. Therefore, the processing of bacteriophage DNA by protoplasts and by competent cells must be different. This sensitive protoplast assay can be used to identify and to isolate various types of DNA repair enzymes

Evaluation of deoxyribonucleic acid (DNA) isolated from human bloodstains exposed to ultraviolet light, heat, humidity, and soil contamination

International Nuclear Information System (INIS)

McNally, L.; Shaler, R.C.; Baird, M.; Balazs, I.; De Forest, P.; Kobilinsky, L.

1989-01-01

This study was designed to analyze the effects of common environmental insults on the ability to obtain deoxyribonucleic acid (DNA) restriction fragment-length polymorphisms (RFLP) patterns from laboratory prepared specimens. The environmental conditions studied include the exposure of dried bloodstains to varying amounts of relative humidity (0, 33, 67, and 98%), heat (37 degree C), and ultraviolet light for periods of up to five days. In addition, the effect of drying over a four-day period in whole blood collected with and without ethylenediaminetetraacetate (EDTA) was examined. The results of the study showed that, under the conditions studied, the integrity of DNA is not altered such that false RFLP patterns are obtained. The only effect observed was that the overall RFLP pattern becomes weaker, but individual RFLP fragments are neither created nor destroyed

Cell division in Escherichia coli BS-12 is hypersensitive to deoxyribonucleic acid damage by ultraviolet light

International Nuclear Information System (INIS)

Bridges, B.A.; Mottershead, R.P.; Green, M.H.

1977-01-01

Escherichia coli BS-12 uvrA lon is hypersensitive to ultraviolet light. On minimal agar plates at densities in excess of about 10(7) bacteria per plate, as few as one or two photoreversible pyrimidine dimers in the entire genome are sufficient to cause inhibition of cell division. Most of the resulting filaments are unable to divide or form a viable colony. Inhibition of cell division appears to be a rapid consequence of replication of deoxyribonucleic acid containing a pyrimidine dimer. Photoreversibility of the inhibition of cell division persists indefinitely, indicating that the continued presence of the pyrimidine dimers (or the continued generation of daughter strand gaps) is necessary to maintain the division-inhibited state. In view of the kinetics for the production of filamentation by ultraviolet light and the extremely low average inducing fluence (0.03 J/m2), it is concluded that the initiating signal is not the same as that causing other inducible phenomena such as prophage induction or Weigle reactivation

Photoreactions of ruthenium(II) and osmium(II) complexes with deoxyribonucleic acid (DNA).

Science.gov (United States)

Moucheron, C; Kirsch-De Mesmaeker, A; Kelly, J M

1997-09-01

The design of Ru(II) and Os(II) complexes which are photoreactive with deoxyribonucleic acid (DNA) represents one of the main targets for the development of novel molecular tools for the study of DNA and, in the future, for the production of new, metal-based, anti-tumor drugs. In this review, we explain how it is possible to make a complex photoreactive with nucleobases and nucleic acids. According to the photophysical behaviour of the Ru(II) compounds, two types of photochemistry are expected: (1) photosubstitution of a ligand by a nucleobase and another monodentate ligand, which takes place from the triplet, metal-centred (3MC) state; this state is populated thermally from the lowest lying triplet metal to ligand charge transfer (3MLCT) state; (2) photoreaction from the 3MLCT state, corresponding to photoredox processes with DNA bases. The two photoreactivities are in competition. By modulating appropriately the redox properties of the 3MLCT state, an electron transfer process from the base to the excited complex takes place, and is directly correlated with DNA cleavage or the formation of an adduct of the complex to DNA. In this adduct, guanine is linked by N2 to the alpha-position of a non-chelating nitrogen of the polyazaaromatic ligand without destruction of the complex. Different strategies are explained which increase the affinity of the complexes for DNA and direct the complex photoreactivity to sites of special DNA topology or targeted sequences of bases. Moreover, the replacement of the Ru(II) ion by the Os(II) ion in the photoreactive complexes leads to an increased specificity of photoreaction. Indeed, only one type of photoreactivity (from the 3MLCT state) is present for the Os(II) complexes because the 3MC state is too high in energy to be populated at room temperature.

Electrogenerated chemiluminescence detection for deoxyribonucleic acid hybridization based on gold nanoparticles carrying multiple probes

International Nuclear Information System (INIS)

Wang Hui; Zhang Chengxiao; Li Yan; Qi Honglan

2006-01-01

A novel sensitive electrogenerated chemiluminescence (ECL) method for the detection deoxyribonucleic acid (DNA) hybridization based on gold nanoparticles carrying multiple probes was developed. Ruthenium bis(2,2'-bipyridine)(2,2'-bipyridine-4,4'-dicarboxylic acid)-N-hydroxysuccinimide ester (Ru(bpy) 2 (dcbpy)NHS) was used as a ECL label and gold nanoparticle as a carrier. Probe single strand DNA (ss-DNA) was self-assembled at the 3'-terminal with a thiol group to the surface of gold nanoparticle and covalently labeled at the 5'-terminal of a phosphate group with Ru(bpy) 2 (dcbpy)NHS and the resulting conjugate (Ru(bpy) 2 (dcbpy)NHS)-ss-DNA-Au, was taken as a ECL probe. When target analyte ss-DNA was immobilized on a gold electrode by self-assembled monolayer technique and then hybridized with the ECL probe to form a double-stranded DNA (ds-DNA), a strong ECL response was electrochemically generated. The ECL intensity was linearly related to the concentration of the complementary sequence (target ss-DNA) in the range from 1.0 x 10 -11 to 1.0 x 10 -8 mol L -1 , and the linear regression equation was S = 57301 + 4579.6 lg C (unit of C is mol L -1 ). A detection limit of 5.0 x 10 -12 mol L -1 for target ss-DNA was achieved. The ECL signal generated from many reporters of ECL probe prepared is greatly amplified, compared to the convention scheme which is based on one reporter per hybridization event

Review of moxifloxacin hydrochloride ophthalmic solution in the treatment of bacterial eye infections

Directory of Open Access Journals (Sweden)

Darlene Miller

2008-03-01

Full Text Available Darlene MillerAbrams Ocular Microbiology Laboratory, Bascom Palmer Eye Institute, Anne Bates Leach Eye Hospital, Miller School of Medicine-University of Miami, FL, USAAbstract: Moxifloxacin hydrochloride ophthalmic solution 0.5% (Vigamox® is the ocular formulation/adaptation of moxifloxacin. Moxifloxacin is a broad spectrum 8-methoxyfluoroquinolone which terminates bacterial growth by binding to DNA gyrase (topoisomerase II and topoisomerase IV, essential bacterial enzymes involved in the replication, translation, repair and recombination of deoxyribonucleic acid. Affinity for both enzymes improves potency and reduces the probability of selecting resistant bacterial subpopulations. Vigamox is a bactericidal, concentration dependent, anti-infective. It is preservative free, and well tolerated with minimal ocular side effects. It provides increased penetration into ocular tissues and fluids with improved activity against Streptococci and Staphylococci species and moderate to excellent activity against clinically relevant, gram- negative ocular pathogens.Keywords: moxifloxacin, vigamox, pharmacodynamic indices, minimal inhibitory concentrations

Initiation points for cellular deoxyribonucleic acid replication in human lymphoid cells converted by Epstein-Barr virus

International Nuclear Information System (INIS)

Oppenheim, A.; Shlomai, Z.; Ben-Bassat, H.

1981-01-01

Replicon size was estimated in two Epstein-Barr virus (EBV)-negative human lymphoma lines, BJAB and Ramos, and four EBV-positive lines derived from the former ones by infection (conversion) with two viral strains, B95-8 and P3HR-1. Logarithmic cultures were pulse-labeled with [/sup -3/H]thymidine, and the deoxyribonucleic acid was spread on microscopic slides and autoradiographed by the method of Huberman and Riggs. Three of the four EBV-converted cell lines, BJAB/B95-8, Ra/B95-8, and Ra/HRIK, were found to have significantly shorter replicons (41, 21, 54% shorter, respectively), i.e., more initiation points, than their EBV-negative parents. BJAB/HRIK had replicons which were only slightly shorter (11%) than those of BJAB. However, analysis of track length demonstrated that extensive track fusion occurred during the labeling of BJAB/HRIK, implying that its true average replicon size is shorter than the observed value. The results indicate that in analogy to simian virus 40, EBV activates new initiation points for cellular DNA replication in EBV-transformed cells

Molecular dynamics simulations of deoxyribonucleic acids and repair enzyme T4 endonuclease V

International Nuclear Information System (INIS)

Pinak, Miroslav

1999-01-01

This report describes the results of molecular dynamics (MD) simulation of deoxyribonucleic acids (DNA) and specific repair enzyme T4 endonuclease V. Namely research described here is focused on the examination of specific recognition process, in which this repair enzyme recognizes the damaged site on the DNA molecule-thymine dimer (TD). TD is frequent DNA damage induced by UV radiation in sun light and unless properly repaired it may be mutagenic or lethal for cell, and is also considered among the major causes of skin cancer. T4 endonuclease V is a DNA specific repair enzyme from bacteriophage T4 that catalyzes the first reaction step of TD repair pathway. MD simulations of three molecules - native DNA dodecamer (12 base pairs), DNA of the same sequence of nucleotides as native one but with TD, and repair enzyme T4 endonuclease V - were performed for 1 ns individually for each molecule. Simulations were analyzed to determine the role of electrostatic interaction in the recognition process. It is found that electrostatic energies calculated for amino acids of the enzyme have positive values of around +15 kcal/mol. The electrostatic energy of TD site has negative value of approximately -9 kcal/mol, different from the nearly neutral value of the respective thymines site of the native DNA. The electrostatic interaction of TD site with surrounding water environment differs from the electrostatic interaction of other nucleotides. Differences found between TD site and respective thymines site of native DNA indicate that the electrostatic energy is an important factor contributing to proper recognition of TD site during scanning process in which enzyme scans the DNA. In addition to the electrostatic energy, the important factor in recognition process might be structural complementarity of enzyme and bent DNA with TD. There is significant kink formed around TD site, that is not observed in native DNA. (author)

Effects of 5 Thio-D-Glucose on cellular adenosine triphosphate levels and deoxyribonucleic acid rejoining in hypoxic and aerobic Chinese hamster cells

International Nuclear Information System (INIS)

Nagle, W.A.; Moss, A.J. Jr.; Roberts, H.G. Jr.; Baker, M.L.

1980-01-01

Intracellular adenosine triphosphate (ATP) levels were measured in both hypoxic and aerobic cultures of V79 Chinese hamster cells treated with 5-thio-D-glucose (5-SH-D-Glc). This glucose analog, a known inhibitor of D-glucose transport and metabolism, reduced ATP in cell cultures allowed to become hypoxic by cell metabolism, but not in aerobic cultures treated similarly. Cells depleted of ATP were unable to rejoin x-ray induced deoxyribonucleic acid (DNA) strand breaks as measured by the alkaline sucrose gradient sedimentation technique. The inference for radiation therapy is that inhibition of glucose metabolism selectively depletes energy reserves in hypoxic cells, rendering these cells more radiosensitive and leading to a more effective tumor treatment

Comparison of the Rate and Extent of Deoxyribonucleic Acid Repair and Semi-Conservative Synthesis in Bacteria Exposed to Ultra-Violet Light

Energy Technology Data Exchange (ETDEWEB)

Billen, D. [Radiation Biology Laboratory and Departments of Microbiology and Radiology, College of Medicine, University of Florida, Gainesville, FL (United States)

1968-08-15

Many bacterial strains possess the ability to repair genetic damage resulting from ultra-violet light (u.v. ) exposure. Of major importance is the occurrence of a 'repair' type of deoxyribonucleic acid (DNA) replication during 'dark repair', which presumably results in the replacement of the damaged portion of the genome. With deuterium, {sup 15}N and {sup 13}C as a density label, and buoyant density centrifugation in CsCl as a means of separating pre and post-irradiation synthesized DNA strands, the rate and extent of DNA repair synthesis in exponential - phase Escherichia coli strain B/r were determined. After u.v. exposure, {sup 3}H-thymine incorporation into the 'heavy' parental DNA strands was used to measure repair synthesis, while {sup 3}H-thymine incorporation into 'light' and newly synthesized DNA strands measured semi-conservative replication. The rate of bases incorporated by repair synthesis in the initial 15 minures of post-irradiation incubation at 37 Degree-Sign C appears to be saturated at a dose of approximately 100 ergs/mm{sup 2}. At higher doses (up to 600 ergs/mm{sup 2}) the increase observed was not proportional to dose. During this initial 15 minutes, less than 1% of the chromosomal DNA was replaced. The amount of DNA synthesized by semi-conservative replication during the initial 15 minutes was reduced with increasing u.v. dose. After exposure to 600 ergs/mm{sup 2}, repair and semiconservative DNA synthesis were nearly equivalent in the irradiated cells after 15 minutes of incubation. Repair synthesis was observed to be terminated by 45 minutes in bacteria exposed to 160 or 500 ergs/mm{sup 2} (64% and 10% survivors, respectively). The amount of genome replaced by repair synthesis at several doses was determined. Starvation for a required amino acid (resulting in an inhibition of protein and ribonucleic acid synthesis) did not prevent the repair synthesis nor grossly alter its extent. The restoration of the semi-conservative mo d e of DNA

Uracil in formic acid hydrolysates of deoxyribonucleic acid

Science.gov (United States)

Schein, Arnold H.

1966-01-01

1. When DNA is hydrolysed with formic acid for 30min. at 175° and the hydrolysate is chromatographed on paper with propan-2-ol–2n-hydrochloric acid, in addition to expected ultraviolet-absorbing spots corresponding to guanine, adenine, cytosine and thymine, an ultraviolet-absorbing region with RF similar to that of uracil can be detected. Uracil was separated from this region and identified by its spectra in acid and alkali, and by its RF in several solvent systems. 2. Cytosine, deoxyribocytidine and deoxyribocytidylic acid similarly treated with formic acid all yielded uracil, as did a mixture of deoxyribonucleotides. 3. Approx. 4% of deoxyribonucleotide cytosine was converted into uracil by the formic acid treatment. ImagesFig. 1. PMID:5949371

A MapReduce approach to diminish imbalance parameters for big deoxyribonucleic acid dataset.

Science.gov (United States)

Kamal, Sarwar; Ripon, Shamim Hasnat; Dey, Nilanjan; Ashour, Amira S; Santhi, V

2016-07-01

In the age of information superhighway, big data play a significant role in information processing, extractions, retrieving and management. In computational biology, the continuous challenge is to manage the biological data. Data mining techniques are sometimes imperfect for new space and time requirements. Thus, it is critical to process massive amounts of data to retrieve knowledge. The existing software and automated tools to handle big data sets are not sufficient. As a result, an expandable mining technique that enfolds the large storage and processing capability of distributed or parallel processing platforms is essential. In this analysis, a contemporary distributed clustering methodology for imbalance data reduction using k-nearest neighbor (K-NN) classification approach has been introduced. The pivotal objective of this work is to illustrate real training data sets with reduced amount of elements or instances. These reduced amounts of data sets will ensure faster data classification and standard storage management with less sensitivity. However, general data reduction methods cannot manage very big data sets. To minimize these difficulties, a MapReduce-oriented framework is designed using various clusters of automated contents, comprising multiple algorithmic approaches. To test the proposed approach, a real DNA (deoxyribonucleic acid) dataset that consists of 90 million pairs has been used. The proposed model reduces the imbalance data sets from large-scale data sets without loss of its accuracy. The obtained results depict that MapReduce based K-NN classifier provided accurate results for big data of DNA. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

pH-responsive deoxyribonucleic acid capture/release by polydopamine functionalized magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Wang, Yu; Ma, Xiangdong; Ding, Chun; Jia, Li, E-mail: jiali@scnu.edu.cn

2015-03-03

Highlights: • PDA@Fe{sub 3}O{sub 4} were prepared and applied for efficient extraction of DNA from pathogens. • The DNA capture and release by PDA@Fe{sub 3}O{sub 4} was pH-induced. • The adsorption capacity of PDA@Fe{sub 3}O{sub 4} for DNA was 161 mg g{sup −1}. • PDA@Fe{sub 3}O{sub 4} based MSPE was combined with PCR and CE for rapid detection of pathogens. - Abstract: Polydopamine functionalized magnetic nanoparticles (PDA@Fe{sub 3}O{sub 4}) were prepared and characterized by transmission electron microscopy, scanning electron microscopy, zeta potential and vibrating sample magnetometry. They were found to enable highly efficient capture of genomic deoxyribonucleic acid (DNA). The adsorption capacity of PDA@Fe{sub 3}O{sub 4} for genomic DNA can reach 161 mg g{sup −1}. The extraction protocol used aqueous solutions for DNA binding to and releasing from the surface of the magnetic particles based on the pH inducing the charge switch of amino and phenolic hydroxyl groups on PDA@Fe{sub 3}O{sub 4}. The extracted DNA with high quality (A{sub 260}/A{sub 280} = 1.80) can be directly used as templates for polymerase chain reaction (PCR) followed by capillary electrophoresis (CE) analysis. None of the toxic chemical reagents and PCR inhibitors was used throughout the whole procedure. PDA@Fe{sub 3}O{sub 4} based magnetic solid phase extraction (MSPE) method was superior to those using commercial kit and traditional phenol–chloroform extraction methods in yield of DNA. The developed PDA@Fe{sub 3}O{sub 4} based MSPE-PCR-CE method was applied for simultaneous and fast detection of Listeria monocytogenes and Escherichia coli O157:H7 in milk.

D-amino acids inhibit initial bacterial adhesion: thermodynamic evidence.

Science.gov (United States)

Xing, Su-Fang; Sun, Xue-Fei; Taylor, Alicia A; Walker, Sharon L; Wang, Yi-Fu; Wang, Shu-Guang

2015-04-01

Bacterial biofilms are structured communities of cells enclosed in a self-produced hydrated polymeric matrix that can adhere to inert or living surfaces. D-Amino acids were previously identified as self-produced compounds that mediate biofilm disassembly by causing the release of the protein component of the polymeric matrix. However, whether exogenous D-amino acids could inhibit initial bacterial adhesion is still unknown. Here, the effect of the exogenous amino acid D-tyrosine on initial bacterial adhesion was determined by combined use of chemical analysis, force spectroscopic measurement, and theoretical predictions. The surface thermodynamic theory demonstrated that the total interaction energy increased with more D-tyrosine, and the contribution of Lewis acid-base interactions relative to the change in the total interaction energy was much greater than the overall nonspecific interactions. Finally, atomic force microscopy analysis implied that the hydrogen bond numbers and adhesion forces decreased with the increase in D-tyrosine concentrations. D-Tyrosine contributed to the repulsive nature of the cell and ultimately led to the inhibition of bacterial adhesion. This study provides a new way to regulate biofilm formation by manipulating the contents of D-amino acids in natural or engineered systems. © 2014 Wiley Periodicals, Inc.

Oxygen-independent direct deoxyribonucleic acid backbone breakage caused by rose bengal and visible light

Energy Technology Data Exchange (ETDEWEB)

Peak, M J; Peak, J G; Foote, C S; Krinsky, N I

1984-01-01

An oxygen enhancement ratio of 10 for the induction of backbone single-strand breaks (SSBs) in purified deoxyribonucleic acid (DNA) by monochromatic 365 nm UV radiation was obtained. Similarly, a dose reduction factor of 10 was observed when the DNA was irradiated in the presence of 0.1 M diazabicyclo(2.2.2)octane (DABCO). To determine whether this breakage of DNA was due to the action of a reactive oxygen species such as singlet oxygen, we used the photosensitizing dye Rose Bengal and visible light as a system for generating singlet oxygen. Treatment of the DNA with Rose Bengal and 545 nm monochromatic light enhanced the rate of induction of SSBs six times, compared with the rate we obtained when the light was used alone. Elimination of oxygen or addition of 0.1 M DABCO during the 545 nm irradiation in the presence of Rose Bengal did not alter the enhancement of SSBs in the DNA caused by Rose Bengal and 545 nm radiation. The induction of SSBs in the DNA caused by irradiation of the DNA by 545 nm light in the presence of Rose Bengal was not enhanced by the use of D/sub 2/O instead of H/sub 2/O as a solvent. The results indicate that Rose Bengal plus visible light can cause biological damage without the intermediacy of reactive oxygen species, i.e. Rose Bengal and visible light can react directly with biological material, in reactions that appear to be type I photosensitized processes, independent of singlet oxygen as an intermediate.

Preliminary individualized chemotherapy for malignant astrocytomas based on O6-methylguanine-deoxyribonucleic acid methyltransferase methylation analysis.

Science.gov (United States)

Watanabe, Takao; Katayama, Yoichi; Ogino, Akiyoshi; Ohta, Takashi; Yoshino, Atsuo; Fukushima, Takao

2006-08-01

O(6)-methylguanine-deoxyribonucleic acid methyltransferase gene (MGMT) methylation is apparently correlated with responsiveness to nitrosourea chemotherapy, suggesting this alkylating agent should be effective against MGMT-methylated tumors. MGMT appears not to be linked to platinum resistance, so platinum chemotherapy should be used for MGMT-unmethylated tumors. This study was a preliminary trial of individualized chemotherapy based on MGMT methylation status in a total of 20 patients with newly diagnosed malignant astrocytomas (9 anaplastic astrocytomas and 11 glioblastomas multiforme). The procarbazine, 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-2(2-chloroethyl)-3-nitrosourea, and vincristine (PAV) regimen was administered to seven patients with MGMT-methylated tumors, and the carboplatin and etoposide (CE) regimen was administered to 13 patients with MGMT-unmethylated tumors. Objective response to the PAV therapy was noted in all three patients with measurable residual tumor (2 complete responses and 1 partial response). Five of the seven patients continued to be disease-free after initiation of the PAV therapy. Objective response to the CE therapy was seen in only one of seven patients with measurable residual tumor (1 partial response). Three of the 13 patients were free from progression, whereas the remaining 10 patients showed early progression. The PAV regimen is effective against MGMT-methylated malignant astrocytomas, but the CE regimen is not useful at the given dose and schedule in MGMT-unmethylated tumors.

Deoxyribonucleic Acid Damage and Repair: Capitalizing on Our Understanding of the Mechanisms of Maintaining Genomic Integrity for Therapeutic Purposes

Directory of Open Access Journals (Sweden)

Jolene Michelle Helena

2018-04-01

Full Text Available Deoxyribonucleic acid (DNA is the self-replicating hereditary material that provides a blueprint which, in collaboration with environmental influences, produces a structural and functional phenotype. As DNA coordinates and directs differentiation, growth, survival, and reproduction, it is responsible for life and the continuation of our species. Genome integrity requires the maintenance of DNA stability for the correct preservation of genetic information. This is facilitated by accurate DNA replication and precise DNA repair. DNA damage may arise from a wide range of both endogenous and exogenous sources but may be repaired through highly specific mechanisms. The most common mechanisms include mismatch, base excision, nucleotide excision, and double-strand DNA (dsDNA break repair. Concurrent with regulation of the cell cycle, these mechanisms are precisely executed to ensure full restoration of damaged DNA. Failure or inaccuracy in DNA repair contributes to genome instability and loss of genetic information which may lead to mutations resulting in disease or loss of life. A detailed understanding of the mechanisms of DNA damage and its repair provides insight into disease pathogeneses and may facilitate diagnosis and the development of targeted therapies.

Physical size of the donor locus and transmission of Haemophilus influenzae ampicillin resistance genes by deoxyribonucleic acid-mediated transformation

International Nuclear Information System (INIS)

Bendler, J.W. III

1976-01-01

The properties of donor deoxyribonucleic acid (DNA) from three clinical isolates and its ability to mediate the transformation of competent Rd strains to ampicillin resistance were examined. A quantitative technique for determining the resistance of individual Haemophilus influenzae cells to ampicillin was developed. When this technique was used, sensitive cells failed to tolerate levels of ampicillin greater than 0.1 to 0.2 μg/ml, whereas three resistant type b β-lactamase-producing strains could form colonies 1- to 3-μg/ml levels of the antibiotic. DNA extracted from the resistant strains elicited transformation of the auxotrophic genes in a multiply auxotrophic Rd strain. For two of the donors, transformation to ampicillin resistance occurred after the uptake of a single DNA molecule approximately 10 4 -fold less frequently than transformation of auxotrophic loci and was not observed to occur at all with the third. The frequency of transformation to ampicillin resistance was two- to fivefold higher in strain BC200 (Okinaka and Barnhart, 1974), which was cured of a defective prophage. All three clinical ampicillin-resistant strains were poor recipients, but the presence of the ampicillin resistant genes in strain BC200 did not reduce its competence

The effect of swim-up and gradient sperm preparation techniques on deoxyribonucleic acid (DNA) fragmentation in subfertile patients.

Science.gov (United States)

Oguz, Yuksel; Guler, Ismail; Erdem, Ahmet; Mutlu, Mehmet Firat; Gumuslu, Seyhan; Oktem, Mesut; Bozkurt, Nuray; Erdem, Mehmet

2018-03-23

To compare the effect of two different sperm preparation techniques, including swim-up and gradient methods on sperm deoxyribonucleic acid (DNA) fragmentation status of semen samples from unexplained and mild male factor subfertile patients undergoing intrauterine insemination (IUI). A prospective randomized study was conducted in 65 subfertile patients, including 34 unexplained and 31 male factor infertility to compare basal and post-procedure DNA fragmentation rates in swim-up and gradient techniques. Sperm DNA fragmentation rates were evaluated by a sperm chromatin dispersion (SCD) test in two portions of each sample of semen that was prepared with either swim-up or gradient techniques. Sperm motility and morphology were also assessed based on WHO 2010 criteria. Swim-up but not gradient method yielded a statistically significant reduction in the DNA fragmented sperm rate after preparation as compared to basal rates, in the semen samples of both unexplained (41.85 ± 22.04 vs. 28.58 ± 21.93, p gradient) and mild male factor (46.61 ± 19.38 vs. 30.32 ± 18.20, p gradient) subgroups. Swim-up method significantly reduces sperm DNA fragmentation rates and may have some prognostic value on intrauterine insemination in patients with decreased sperm DNA integrity.

Injury-induced inhibition of small intestinal protein and nucleic acid synthesis

International Nuclear Information System (INIS)

Carter, E.A.; Hatz, R.A.; Yarmush, M.L.; Tompkins, R.G.

1990-01-01

Small intestinal mucosal weight and nutrient absorption are significantly diminished early after cutaneous thermal injuries. Because these intestinal properties are highly dependent on rates of nucleic acid and protein synthesis, in vivo incorporation of thymidine, uridine, and leucine into small intestinal deoxyribonucleic acid, ribonucleic acid, and proteins were measured. Deoxyribonucleic acid synthesis was markedly decreased with the lowest thymidine incorporation in the jejunum (p less than 0.01); these findings were confirmed by autoradiographic identification of radiolabeled nuclei in the intestinal crypts. Protein synthesis was decreased by 6 h postinjury (p less than 0.01) but had returned to normal by 48 h. Consistent with a decreased rate of protein synthesis, ribonucleic acid synthesis was also decreased 18 h postinjury (p less than 0.01). These decreased deoxyribonucleic acid, ribonucleic acid, and protein synthesis rates are not likely a result of ischemia because in other studies of this injury model, intestinal blood flow was not significantly changed by the burn injury. Potentially, factors initiating the acute inflammatory reaction may directly inhibit nucleic acid and protein synthesis and lead to alterations in nutrient absorption and intestinal barrier function after injury

Isolation and identification of biocellulose-producing bacterial strains from Malaysian acidic fruits.

Science.gov (United States)

Voon, W W Y; Rukayadi, Y; Meor Hussin, A S

2016-05-01

Biocellulose (BC) is pure extracellular cellulose produced by several species of micro-organisms that has numerous applications in the food, biomedical and paper industries. However, the existing biocellulose-producing bacterial strain with high yield was limited. The aim of this study was to isolate and identify the potential biocellulose-producing bacterial isolates from Malaysian acidic fruits. One hundred and ninety-three bacterial isolates were obtained from 19 local acidic fruits collected in Malaysia and screened for their ability to produce BC. A total of 15 potential bacterial isolates were then cultured in standard Hestrin-Schramm (HS) medium statically at 30°C for 2 weeks to determine the BC production. The most potent bacterial isolates were identified using 16S rRNA gene sequence analysis, morphological and biochemical characteristics. Three new and potent biocellulose-producing bacterial strains were isolated from soursop fruit and identified as Stenotrophomonas maltophilia WAUPM42, Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. Stenotrophomonas maltophilia WAUPM42 was the most potent biocellulose-producing bacterial strain that produced the highest amount of BC 0·58 g l(-1) in standard HS medium. Whereas, the isolates P. vagans WAUPM45 and B. fluminensis WAUPM53 showed 0·50 and 0·52 g l(-1) of BC production, respectively. Biocellulose (BC) is pure extracellular cellulose that is formed by many micro-organisms in the presence of carbon source and acidic condition. It can replace plant-based cellulose in multifarious applications due to its unique characteristics. In this study, three potential biocellulose-producing bacterial strains were obtained from Malaysian acidic fruits and identified as Stenotrophomonas maltophilia WAUPM42, Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. This study reports for the first time the new biocellulose-producing bacterial strains isolated from Malaysian acidic fruits. © 2016 The

Lactic Acid Bacterial Vaginosis among Outpatients in Addis Ababa ...

African Journals Online (AJOL)

Background: Bacterial vaginosis (BV) is a polymicrobial syndrome in which a decrease in vaginal acidity and concentration of lactobacilli is accompanied by an increase of other pathogenic micro-organisms. The distribution of lactic acid bacteria in vaginal environment of Ethiopian women has not been documented.

Evaluation of Deoxyribonucleic Acid Toxicity Induced by the Radiopharmaceutical 99mTechnetium-Methylenediphosphonic Acid and by Stannous Chloride in Wistar Rats

Directory of Open Access Journals (Sweden)

Adriano Caldeira-de-Araujo

2012-11-01

Full Text Available Radiopharmaceuticals are employed in patient diagnostics and disease treatments. Concerning the diagnosis aspect, technetium-99m (99mTc is utilized to label radiopharmaceuticals for single photon computed emission tomography (SPECT due to its physical and chemical characteristics. 99mTc fixation on pharmaceuticals depends on a reducing agent, stannous chloride (SnCl2 being the most widely-utilized. The genotoxic, clastogenic and anegenic properties of the 99mTc-MDP(methylene diphosphonate used for bone SPECT and SnCl2 were evaluated in Wistar rat blood cells using the Comet assay and micronucleus test. The experimental approach was to endovenously administer NaCl 0.9% (negative control, cyclophosphamide 50 mg/kg b.w. (positive control, SnCl2 500 μg/mL or 99mTc-MDP to animals and blood samples taken immediately before the injection, 3, and 24 h after (in the Comet assay and 36 h after, for micronucleus test. The data showed that both SnCl2 and 99mTc-MDP-induced deoxyribonucleic acid (DNA strand breaks in rat total blood cells, suggesting genotoxic potential. The 99mTc-MDP was not able to induce a significant DNA strand breaks increase in in vivo assays. Taken together, the data presented here points to the formation of a complex between SnCl2 in the radiopharmaceutical 99mTc-MDP, responsible for the decrease in cell damage, compared to both isolated chemical agents. These findings are important for the practice of nuclear medicine.

Cisplatin Targeting of Bacterial Ribosomal RNA Hairpins

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Gayani N. P. Dedduwa-Mudalige

2015-09-01

Full Text Available Cisplatin is a clinically important chemotherapeutic agent known to target purine bases in nucleic acids. In addition to major deoxyribonucleic acid (DNA intrastrand cross-links, cisplatin also forms stable adducts with many types of ribonucleic acid (RNA including siRNA, spliceosomal RNAs, tRNA, and rRNA. All of these RNAs play vital roles in the cell, such as catalysis of protein synthesis by rRNA, and therefore serve as potential drug targets. This work focused on platination of two highly conserved RNA hairpins from E. coli ribosomes, namely pseudouridine-modified helix 69 from 23S rRNA and the 790 loop of helix 24 from 16S rRNA. RNase T1 probing, MALDI mass spectrometry, and dimethyl sulfate mapping revealed platination at GpG sites. Chemical probing results also showed platination-induced RNA structural changes. These findings reveal solvent and structural accessibility of sites within bacterial RNA secondary structures that are functionally significant and therefore viable targets for cisplatin as well as other classes of small molecules. Identifying target preferences at the nucleotide level, as well as determining cisplatin-induced RNA conformational changes, is important for the design of more potent drug molecules. Furthermore, the knowledge gained through studies of RNA-targeting by cisplatin is applicable to a broad range of organisms from bacteria to human.

Identification of Three Kinds of Citri Reticulatae Pericarpium Based on Deoxyribonucleic Acid Barcoding and High-performance Liquid Chromatography-diode Array Detection-electrospray Ionization/Mass Spectrometry/Mass Spectrometry Combined with Chemometric Analysis

Science.gov (United States)

Yu, Xiaoxue; Zhang, Yafeng; Wang, Dongmei; Jiang, Lin; Xu, Xinjun

2018-01-01

Background: Citri Reticulatae Pericarpium is the dried mature pericarp of Citrus reticulata Blanco which can be divided into “Chenpi” and “Guangchenpi.” “Guangchenpi” is the genuine Chinese medicinal material in Xinhui, Guangdong province; based on the greatest quality and least amount, it is most expensive among others. Hesperidin is used as the marker to identify Citri Reticulatae Pericarpium described in the Chinese Pharmacopoeia 2010. However, both “Chenpi” and “Guangchenpi” contain hesperidin so that it is impossible to differentiate them by measuring hesperidin. Objective: Our study aims to develop an efficient and accurate method to separate and identify “Guangchenpi” from other Citri Reticulatae Pericarpium. Materials and Methods: The genomic deoxyribonucleic acid (DNA) of all the materials was extracted and then the internal transcribed spacer 2 was amplified, sequenced, aligned, and analyzed. The secondary structures were created in terms of the database and website established by Jörg Schultz et al. High-performance liquid chromatography-diode array detection-electrospray Ionization/mass spectrometry (HPLC-DAD-ESI-MS)/MS coupled with chemometric analysis was applied to compare the differences in chemical profiles of the three kinds of Citri Reticulatae Pericarpium. Results: A total of 22 samples were classified into three groups. The results of DNA barcoding were in accordance with principal component analysis and hierarchical cluster analysis. Eight compounds were deduced from HPLC-DAD-ESI-MS/MS. Conclusions: This method is a reliable and effective tool to differentiate the three Citri Reticulatae Pericarpium. SUMMARY The internal transcribed spacer 2 regions and the secondary structure among three kinds of Citri Reticulatae Pericarpium varied considerablyAll the 22 samples were analyzed by high-performance liquid chromatography (HPLC) to obtain the chemical profilesPrincipal component analysis and hierarchical cluster analysis

Evaluation of different lactic acid bacterial strains for probiotic characteristics

OpenAIRE

B. Srinu,; T. Madhava Rao,; P. V. Mallikarjuna Reddy; K. Kondal Reddy

2013-01-01

Objective: The objective of the present study was to collect different Lactic acid bacterial strains from culture collection centers and screen their functional probiotic characteristics such as acid tolerance, bile tolerance, antibacterial activity and antibiotic sensitivity for their commercial use. Materials and Methods: Acid and bile tolerence of selected LAB(Lactic acid bacteria) was determined. The antibiotic resistance of Lactobacillus species was assessed using different antibiotic di...

Identification of a Herbal Powder by Deoxyribonucleic Acid Barcoding and Structural Analyses.

Science.gov (United States)

Sheth, Bhavisha P; Thaker, Vrinda S

2015-10-01

Authentic identification of plants is essential for exploiting their medicinal properties as well as to stop the adulteration and malpractices with the trade of the same. To identify a herbal powder obtained from a herbalist in the local vicinity of Rajkot, Gujarat, using deoxyribonucleic acid (DNA) barcoding and molecular tools. The DNA was extracted from a herbal powder and selected Cassia species, followed by the polymerase chain reaction (PCR) and sequencing of the rbcL barcode locus. Thereafter the sequences were subjected to National Center for Biotechnology Information (NCBI) basic local alignment search tool (BLAST) analysis, followed by the protein three-dimension structure determination of the rbcL protein from the herbal powder and Cassia species namely Cassia fistula, Cassia tora and Cassia javanica (sequences obtained in the present study), Cassia Roxburghii, and Cassia abbreviata (sequences retrieved from Genbank). Further, the multiple and pairwise structural alignment were carried out in order to identify the herbal powder. The nucleotide sequences obtained from the selected species of Cassia were submitted to Genbank (Accession No. JX141397, JX141405, JX141420). The NCBI BLAST analysis of the rbcL protein from the herbal powder showed an equal sequence similarity (with reference to different parameters like E value, maximum identity, total score, query coverage) to C. javanica and C. roxburghii. In order to solve the ambiguities of the BLAST result, a protein structural approach was implemented. The protein homology models obtained in the present study were submitted to the protein model database (PM0079748-PM0079753). The pairwise structural alignment of the herbal powder (as template) and C. javanica and C. roxburghii (as targets individually) revealed a close similarity of the herbal powder with C. javanica. A strategy as used here, incorporating the integrated use of DNA barcoding and protein structural analyses could be adopted, as a novel

Study of the interaction of enzyme Heparanase 1 (HPSE1) active with deoxyribonucleic acids; Estudo de interacao da enzima Heparanase 1 (HPSE 1) ativa com acido desoxirribonucleicos

Energy Technology Data Exchange (ETDEWEB)

Cid, Gisele da Silva

2016-07-01

The human heparanase 1 (HPSE 1) is a protein with multiple functions and has emerged as a promising therapeutic target in the context of antitumor therapy. This fact is due to its clinical relevance in the tumor development and progression, as determined by their enzymatic ability to degrade heparan sulfate (HS), the main constituent of the extracellular matrix, providing a tumor microenvironment to tumor dissemination. In addition, this protein plays a significant role in the increase of tumor cells migration ionizing radiation dose delivery in radiotherapy from the increase in the expression levels of HPSE1. In order to evaluate in more detail the functions of active HPSE1, it has been proposed to characterize the interaction of human heparanase protein 1 with deoxyribonucleic acids. Our results are original and point to a new function of HPSE1 of the endonuclease type. (author)

Effect of crushed mussel shell addition on bacterial growth in acid polluted soils

DEFF Research Database (Denmark)

Fernandez Calviño, David; Garrido-Rodríguez, B.; Arias-Estévez, M.

2015-01-01

We applied three different doses of crushed mussel shell (CMS) on two Cu-polluted acid soils to study the effect of these amendments on the growth of the bacterial community during 730 days. Soil pH increased in the short and medium term due to CMS addition. In a first stage, bacterial growth...... was lower in the CMS-amended than in the un-amended samples. Thereafter, bacterial growth increased slowly. The soil having the highest initial pH value (4.5) showed the first significant increase in bacterial growth 95 days after the CMS amendment. However, in the soil with the lowest initial pH value (3...... as an agronomic sound practice for strongly acid soils (pH

Measurement of the incorporation rates of four amino acids into proteins for estimating bacterial production.

Science.gov (United States)

Servais, P

1995-03-01

In aquatic ecosystems, [(3)H]thymidine incorporation into bacterial DNA and [(3)H]leucine incorporation into proteins are usually used to estimate bacterial production. The incorporation rates of four amino acids (leucine, tyrosine, lysine, alanine) into proteins of bacteria were measured in parallel on natural freshwater samples from the basin of the river Meuse (Belgium). Comparison of the incorporation into proteins and into the total macromolecular fraction showed that these different amino acids were incorporated at more than 90% into proteins. From incorporation measurements at four subsaturated concentrations (range, 2-77 nm), the maximum incorporation rates were determined. Strong correlations (r > 0.91 for all the calculated correlations) were found between the maximum incorporation rates of the different tested amino acids over a range of two orders of magnitude of bacterial activity. Bacterial production estimates were calculated using theoretical and experimental conversion factors. The productions calculated from the incorporation rates of the four amino acids were in good concordance, especially when the experimental conversion factors were used (slope range, 0.91-1.11, and r > 0.91). This study suggests that the incorporation of various amino acids into proteins can be used to estimate bacterial production.

ATR-FTIR Spectroscopic Evidence for Biomolecular Phosphorus and Carboxyl Groups Facilitating Bacterial Adhesion to Iron Oxides

Science.gov (United States)

Parikh, Sanjai J.; Mukome, Fungai N.D.; Zhang, Xiaoming

2014-01-01

Attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy has been used to probe the binding of bacteria to hematite (α-Fe2O3) and goethite (α-FeOOH). In situ ATR-FTIR experiments with bacteria (Pseudomonas putida, P. aeruginosa, Escherichia coli), mixed amino acids, polypeptide extracts, deoxyribonucleic acid (DNA), and a suite of model compounds were conducted. These compounds represent carboxyl, catecholate, amide, and phosphate groups present in siderophores, amino acids, polysaccharides, phospholipids, and DNA. Due in part to the ubiquitous presence of carboxyl groups in biomolecules, numerous IR peaks corresponding to outer-sphere or unbound (1400 cm−1) and inner-sphere (1310-1320 cm−1) coordinated carboxyl groups are noted following reaction of bacteria and biomolecules with α-Fe2O3 and α-FeOOH. However, the data also reveal that the presence of low-level amounts (i.e., 0.45-0.79%) of biomolecular phosphorous groups result in strong IR bands at ~1043 cm−1, corresponding to inner-sphere Fe-O-P bonds, underscoring the importance of bacteria associated P-containing groups in biomolecule and cell adhesion. Spectral comparisons also reveal slightly greater P-O-Fe contributions for bacteria (Pseudomonad, E. coli) deposited on α-FeOOH, as compared to α-Fe2O3. This data demonstrates that slight differences in bacterial adhesion to Fe oxides can be attributed to bacterial species and Fe-oxide minerals. However, more importantly, the strong binding affinity of phosphate in all bacteria samples to both Fe-oxides results in the formation of inner-sphere Fe-O-P bonds, signifying the critical role of biomolecular P in the initiation of bacterial adhesion. PMID:24859052

Reduced Bacterial Wilt in Tomato Plants by Bactericidal Peroxyacetic Acid Mixture Treatment

Directory of Open Access Journals (Sweden)

Jeum Kyu Hong

2018-02-01

Full Text Available Peroxyacetic acid mixture Perosan, composed of peroxyacetic acid, hydrogen peroxide and acetic acid, was evaluated for eco-friendly management of tomato bacterial wilt by Ralstonia pseudosolanacearum. Perosan drastically suppressed in vitro growth of R. pseudosolanacearum in liquid cultures in dose- and incubation time-dependent manners. Higher perosan doses (0.1 and 1% caused lowered pH and phytotoxicity to detached leaves of two tomato cultivars Cupirang and Benekia 220 in aqueous solution. Treatment with 0.01% of Perosan delayed wilting symptom significantly in the detached leaves of two cultivars inoculated with R. pseudosolanacearum (10⁷ cfu/ml. Soil drenching of 5% Perosan solution in pots caused severe tissue collapse of tomato seedlings at the four-week-old stage of two tomato cultivars. Treatment with 1% Perosan by soil-drenching significantly reduced bacterial wilt in the tomato seedlings of two cultivars. These findings suggest that Perosan treatment can be applied to suppress bacterial wilt during tomato production.

Engineering Escherichia coli for Biodiesel Production Utilizing a Bacterial Fatty Acid Methyltransferase▿†

Science.gov (United States)

Nawabi, Parwez; Bauer, Stefan; Kyrpides, Nikos; Lykidis, Athanasios

2011-01-01

The production of low-cost biofuels in engineered microorganisms is of great interest due to the continual increase in the world's energy demands. Biodiesel is a renewable fuel that can potentially be produced in microbes cost-effectively. Fatty acid methyl esters (FAMEs) are a common component of biodiesel and can be synthesized from either triacylglycerol or free fatty acids (FFAs). Here we report the identification of a novel bacterial fatty acid methyltransferase (FAMT) that catalyzes the formation of FAMEs and 3-hydroxyl fatty acid methyl esters (3-OH-FAMEs) from the respective free acids and S-adenosylmethionine (AdoMet). FAMT exhibits a higher specificity toward 3-hydroxy free fatty acids (3-OH-FFAs) than FFAs, synthesizing 3-hydroxy fatty acid methyl esters (3-OH-FAMEs) in vivo. We have also identified bacterial members of the fatty acyl-acyl carrier protein (ACP) thioesterase (FAT) enzyme family with distinct acyl chain specificities. These bacterial FATs exhibit increased specificity toward 3-hydroxyacyl-ACP, generating 3-OH-FFAs, which can subsequently be utilized by FAMTs to produce 3-OH-FAMEs. PhaG (3-hydroxyacyl ACP:coenzyme A [CoA] transacylase) constitutes an alternative route to 3-OH-FFA synthesis; the coexpression of PhaG with FAMT led to the highest level of accumulation of 3-OH-FAMEs and FAMEs. The availability of AdoMet, the second substrate for FAMT, is an important factor regulating the amount of methyl esters produced by bacterial cells. Our results indicate that the deletion of the global methionine regulator metJ and the overexpression of methionine adenosyltransferase result in increased methyl ester synthesis. PMID:21926202

Isolation of bacterial cellulose nanocrystalline from pineapple peel waste: Optimization of acid concentration in the hydrolysis method

Science.gov (United States)

Anwar, Budiman; Rosyid, Nurul Huda; Effendi, Devi Bentia; Nandiyanto, Asep Bayu Dani; Mudzakir, Ahmad; Hidayat, Topik

2016-02-01

Isolation of needle-shaped bacterial cellulose nanocrystalline with a diameter of 16-64 nm, a fiber length of 258-806 nm, and a degree of crystallinity of 64% from pineapple peel waste using an acid hydrolysis process was investigated. Experimental showed that selective concentration of acid played important roles in isolating the bacterial cellulose nanocrystalline from the cellulose source. To achieve the successful isolation of bacterial cellulose nanocrystalline, various acid concentrations were tested. To confirm the effect of acid concentration on the successful isolation process, the reaction conditions were fixed at a temperature of 50°C, a hydrolysis time of 30 minutes, and a bacterial cellulose-to-acid ratio of 1:50. Pineapple peel waste was used as a model for a cellulose source because to the best of our knowledge, there is no report on the use of this raw material for producing bacterial cellulose nanocrystalline. In fact, this material can be used as an alternative for ecofriendly and cost-free cellulose sources. Therefore, understanding in how to isolate bacterial cellulose nanocrystalline from pineapple peel waste has the potential for large-scale production of inexpensive cellulose nanocrystalline.

In vitro antioxidant potential and deoxyribonucleic acid protecting activity of CNB-001, a novel pyrazole derivative of curcumin

Directory of Open Access Journals (Sweden)

Richard L Jayaraj

2014-01-01

Full Text Available Background: Free radicals are underpinned to initiate cascade of toxic events leading to oxidative stress and resultant cell death in many neurodegenerative disorders. Now-a-days antioxidants have become mandatory in the treatment of various diseases apart from the drug′s modes of action. CNB-001, a novel hybrid molecule synthesized by combining curcumin and cyclohexyl bisphenol A is known to possess various biological activities, but the antioxidative property of the compound has not yet been elucidated. Aim: The present study is aimed to analyze various free radicals scavenging by employing in vitro antioxidant assays and to evaluate the deoxyribonucleic acid (DNA protecting the ability of CNB-001 against hydroxyl radicals. Materials and methods: The in vitro antioxidant potential of CNB-001 was evaluated by analyzing its ability to scavenge DPPH, ABTS, nitric oxide, superoxide, hydrogen peroxide, superoxide anion, hydroxyl, hydrogen peroxide radicals and reducing power using spectroscopic method. The DNA protecting activity of CNB-001 was also evaluated on pUC19 plasmid DNA subjected to hydroxyl radicals using standard agarose gel electrophoresis. Results: From the assays, it was observed that CNB-001 scavenged free radicals effectively in a dose dependent manner. CNB-001 scavenged 2,2-diphenyl-1-picrylhydrazyl (IC50 = 44.99 μg/ml, 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (IC50 = 17.99 μg/ml, nitric oxide (IC50 = 1.36 μg/ml, superoxide radical (IC50 = 77.17 μg/ml, hydrogen peroxide (IC50 = 492.7 μg/ml, superoxide (IC50 = 36.92 μg/ml and hydroxyl (IC50 = 456.5 μg/ml radicals effectively and the reducing power was found to be 11.53 μg/ml. CNB-001 showed considerable protecting activity against plasmid DNA (pUC19 strand scission by ·OH at dose dependent manner. Conclusion: Results from these assays concluded that CNB-001 has a good antioxidant potential by reducing reactive oxygen and reactive nitrogen radicals and it

Cost-effective production of bacterial cellulose using acidic food industry by-products.

Science.gov (United States)

Revin, Victor; Liyaskina, Elena; Nazarkina, Maria; Bogatyreva, Alena; Shchankin, Mikhail

2018-03-13

To reduce the cost of obtaining bacterial cellulose, acidic by-products of the alcohol and dairy industries were used without any pretreatment or addition of other nitrogen sources. Studies have shown that the greatest accumulation of bacterial cellulose (6.19g/L) occurs on wheat thin stillage for 3 days of cultivation under dynamic conditions, which is almost 3 times higher than on standard Hestrin and Schramm medium (2.14g/L). The use of whey as a nutrient medium makes it possible to obtain 5.45g/L bacterial cellulose under similar conditions of cultivation. It is established that the pH of the medium during the growth of Gluconacetobacter sucrofermentans B-11267 depends on the feedstock used and its initial value. By culturing the bacterium on thin stillage and whey, there is a decrease in the acidity of the waste. It is shown that the infrared spectra of bacterial cellulose obtained in a variety of environments have a similar character, but we found differences in the micromorphology and crystallinity of the resulting biopolymer. Copyright © 2018 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Lactic acid levels in pleural fluid from patients with bacterial pleuritis.

OpenAIRE

Riley, T V

1985-01-01

Pleural fluid lactic acid estimations were carried out on 60 samples by gas-liquid chromatography. Lactic acid levels in 12 patients with bacterial pleural infection were statistically significantly higher (mean, 287 mg/dl; range, 135 to 482 mg/dl) than in 18 patients with malignancy (mean, 71 mg/dl; range, 24 to 157 mg/dl) and 30 other patients with pleural effusions (mean, 19 mg/dl; range, 10 to 57 mg/dl). The determination of pleural fluid lactic acid may help in differentiating between em...

MOLECULAR EVALUATION OF CHANGES IN PLANKTONIC BACTERIAL POPULATIONS RESULTING FROM EQUINE FECAL CONTAMINATION IN A SUB-WATERSHED

Science.gov (United States)

Considerable emphasis has been placed on developing watershed-based strategies with the potential to reduce non-point-source fecal contamination. Molecular methods applied used 16S-ribosomal-deoxyribonucleic-acid (rDNA) to try to determine sources of fecal contamination. Objectiv...

Time-resolved studies of energy transfer from meso-tetrakis(N-methylpyridinium-4-yl)- porphyrin to 3,3'-diethyl-2,2'-thiatricarbocyanine iodide along deoxyribonucleic acid Chain.

Science.gov (United States)

Kakiuchi, Toshifumi; Ito, Fuyuki; Nagamura, Toshihiko

2008-04-03

The excitation energy transfer from meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (TMPyP) to 3,3'-diethyl-2,2'-thiatricarbocyanine iodide (DTTCI) along the deoxyribonucleic acid (DNA) double strand was investigated by the steady-state absorption and fluorescence measurements and time-resolved fluorescence measurements. The steady-state fluorescence spectra showed that the near-infrared fluorescence of DTTCI was strongly enhanced up to 86 times due to the energy transfer from the excited TMPyP molecule in DNA buffer solution. Furthermore, we elucidated the mechanism of fluorescence quenching and enhancement by the direct observation of energy transfer using the time-resolved measurements. The fluorescence quenching of TMPyP chiefly consists of a static component due to the formation of complex and dynamic components due to the excitation energy transfer. In a heterogeneous one-dimensional system such as a DNA chain, it was proved that the energy transfer process only carries out within the critical distance based on the Förster theory and within a threshold value estimated from the modified Stern-Volmer equation. The present results showed that DNA chain is one of the most powerful tools for nanoassemblies and will give a novel concepts of material design.

Effect of Thymine Starvation on Messenger Ribonucleic Acid Synthesis in Escherichia coli

Science.gov (United States)

Luzzati, Denise

1966-01-01

Luzzati, Denise (Institut de Biologie Physico-Chimique, Paris, France). Effect of thymine starvation on messenger ribonucleic acid synthesis in Escherichia coli. J. Bacteriol. 92:1435–1446. 1966.—During the course of thymine starvation, the rate of synthesis of messenger ribonucleic acid (mRNA, the rapidly labeled fraction of the RNA which decays in the presence of dinitrophenol or which hybridizes with deoxyribonucleic acid) decreases exponentially, in parallel with the viability of the thymine-starved bacteria. The ability of cell-free extracts of starved bacteria to incorporate ribonucleoside triphosphates into RNA was determined; it was found to be inferior to that of extracts from control cells. The analysis of the properties of cell-free extracts of starved cells shows that their decreased RNA polymerase activity is the consequence of a modification of their deoxyribonucleic acid, the ability of which to serve as a template for RNA polymerase decreases during starvation. PMID:5332402

Crystallization and X-ray diffraction studies of a complete bacterial fatty-acid synthase type I

International Nuclear Information System (INIS)

Enderle, Mathias; McCarthy, Andrew; Paithankar, Karthik Shivaji; Grininger, Martin

2015-01-01

Bacterial and fungal type I fatty-acid synthases (FAS I) are evolutionarily connected, as bacterial FAS I is considered to be the ancestor of fungal FAS I. In this work, the production, crystallization and X-ray diffraction data analysis of a bacterial FAS I are reported. While a deep understanding of the fungal and mammalian multi-enzyme type I fatty-acid synthases (FAS I) has been achieved in recent years, the bacterial FAS I family, which is narrowly distributed within the Actinomycetales genera Mycobacterium, Corynebacterium and Nocardia, is still poorly understood. This is of particular relevance for two reasons: (i) although homologous to fungal FAS I, cryo-electron microscopic studies have shown that bacterial FAS I has unique structural and functional properties, and (ii) M. tuberculosis FAS I is a drug target for the therapeutic treatment of tuberculosis (TB) and therefore is of extraordinary importance as a drug target. Crystals of FAS I from C. efficiens, a homologue of M. tuberculosis FAS I, were produced and diffracted X-rays to about 4.5 Å resolution

Crystallization and X-ray diffraction studies of a complete bacterial fatty-acid synthase type I

Energy Technology Data Exchange (ETDEWEB)

Enderle, Mathias [Goethe University Frankfurt, Max-von-Laue-Strasse 15, 60438 Frankfurt am Main (Germany); Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried (Germany); McCarthy, Andrew [EMBL Grenoble, 71 Avenue des Martyrs, 38042 Grenoble CEDEX 9 (France); Paithankar, Karthik Shivaji, E-mail: paithankar@em.uni-frankfurt.de [Goethe University Frankfurt, Max-von-Laue-Strasse 15, 60438 Frankfurt am Main (Germany); Grininger, Martin, E-mail: paithankar@em.uni-frankfurt.de [Goethe University Frankfurt, Max-von-Laue-Strasse 15, 60438 Frankfurt am Main (Germany); Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried (Germany)

2015-10-23

Bacterial and fungal type I fatty-acid synthases (FAS I) are evolutionarily connected, as bacterial FAS I is considered to be the ancestor of fungal FAS I. In this work, the production, crystallization and X-ray diffraction data analysis of a bacterial FAS I are reported. While a deep understanding of the fungal and mammalian multi-enzyme type I fatty-acid synthases (FAS I) has been achieved in recent years, the bacterial FAS I family, which is narrowly distributed within the Actinomycetales genera Mycobacterium, Corynebacterium and Nocardia, is still poorly understood. This is of particular relevance for two reasons: (i) although homologous to fungal FAS I, cryo-electron microscopic studies have shown that bacterial FAS I has unique structural and functional properties, and (ii) M. tuberculosis FAS I is a drug target for the therapeutic treatment of tuberculosis (TB) and therefore is of extraordinary importance as a drug target. Crystals of FAS I from C. efficiens, a homologue of M. tuberculosis FAS I, were produced and diffracted X-rays to about 4.5 Å resolution.

Ionizing radiation damage to the folded chromosome of Escherichia coli K-12: repair of double-strand breaks in deoxyribonucleic acid

International Nuclear Information System (INIS)

Ulmer, M.K.; Gomez, R.F.; Sinskevy, A.J.

1979-01-01

The extremely gentle lysis and unfolding procedures that have been developed for the isolation of nucleoid deoxyribonucleic acid yield undamaged, replicating genomes, thus permitting direct measurement of the formation and repair of DNA double-strand breaks at biologically significant doses of ionizing radiation. Repair of ionizing radiation damage to folded chromosomes of Escherichia coli K-12 strain AB2497 was observed within 2 to 3 h of post-irradiation incubation in growth medium. Such behavior was not observed after post-irradiation incubation in growth medium of a recA13 strain (strain AB2487). A model based on recombinational repair is proposed to explain the formation of 2,200 to 2,300S material during early stages of incubation and to explain subsequent changes in the gradient profiles. Association of unrepaired DNA with the plasma membrane is proposed to explain the formation of a peak of rapidly sedimenting material (greater than 3,100S) during the later stage of repair. Direct evidence of repair of double-strand breaks during post-irradiation incubation in growth medium was obtained from gradient profiles of DNA from ribonuclease-digested chromosomes. The sedimentation coefficient of broken molecules was restored to the value of unirradiated DNA after 2 to 3 h of incubation, and the fraction of the DNA repaired in this fashion was equal to the fraction of cells that survived at the same dose. An average of 2.7 double-strand breaks per genome per lethal event was observed, suggesting that one to two double-strand breaks per genome are repairable in E. coli K-12 strain AB2497

Synergism between hydrogen peroxide and seventeen acids against six bacterial strains.

Science.gov (United States)

Martin, H; Maris, P

2012-09-01

The objective of this study was to evaluate the bactericidal efficacy of hydrogen peroxide administered in combination with 17 mineral and organic acids authorized for use in the food industry. The assays were performed on a 96-well microplate using a microdilution technique based on the checkerboard titration method. The six selected strains were reference strains and strains representative of contaminating bacteria in the food industry. Each synergistic hydrogen peroxide/acid combination found after 5-min contact time at 20°C in distilled water was then tested in conditions simulating four different use conditions. Thirty-two combinations were synergistic in distilled water; twenty-five of these remained synergistic with one or more of the four mineral and organic interfering substances selected. Hydrogen peroxide/formic acid combination was synergistic for all six bacterial strains in distilled water and remained synergistic with interfering substances. Six other combinations maintained their synergistic effect in the presence of an organic load but only for one or two bacterial strains. Synergistic combinations of disinfectants were revealed, among them the promising hydrogen peroxide/formic acid combination. A rapid screening method was proposed and used to reveal the synergistic potential of disinfectant and/or sanitizer combinations. © 2012 ANSES Fougères Laboratory Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

A rapid colorimetric screening method for vanillic acid and vanillin-producing bacterial strains.

Science.gov (United States)

Zamzuri, N A; Abd-Aziz, S; Rahim, R A; Phang, L Y; Alitheen, N B; Maeda, T

2014-04-01

To isolate a bacterial strain capable of biotransforming ferulic acid, a major component of lignin, into vanillin and vanillic acid by a rapid colorimetric screening method. For the production of vanillin, a natural aroma compound, we attempted to isolate a potential strain using a simple screening method based on pH change resulting from the degradation of ferulic acid. The strain Pseudomonas sp. AZ10 UPM exhibited a significant result because of colour changes observed on the assay plate on day 1 with a high intensity of yellow colour. The biotransformation of ferulic acid into vanillic acid by the AZ10 strain provided the yield (Yp/s ) and productivity (Pr ) of 1·08 mg mg(-1) and 53·1 mg L(-1) h(-1) , respectively. In fact, new investigations regarding lignin degradation revealed that the strain was not able to produce vanillin and vanillic acid directly from lignin; however, partially digested lignin by mixed enzymatic treatment allowed the strain to produce 30·7 mg l(-1) and 1·94 mg l(-1) of vanillic acid and biovanillin, respectively. (i) The rapid colorimetric screening method allowed the isolation of a biovanillin producer using ferulic acid as the sole carbon source. (ii) Enzymatic treatment partially digested lignin, which could then be utilized by the strain to produce biovanillin and vanillic acid. To the best of our knowledge, this is the first study reporting the use of a rapid colorimetric screening method for bacterial strains producing vanillin and vanillic acid from ferulic acid. © 2013 The Society for Applied Microbiology.

Effect of simulated acid rain on fluorine mobility and the bacterial community of phosphogypsum.

Science.gov (United States)

Wang, Mei; Tang, Ya; Anderson, Christopher W N; Jeyakumar, Paramsothy; Yang, Jinyan

2018-03-21

Contamination of soil and water with fluorine (F) leached from phosphogypsum (PG) stacks is a global environmental issue. Millions of tons of PG is produced each year as a by-product of fertilizer manufacture, and in China, weathering is exacerbated by acid rain. In this work, column leaching experiments using simulated acid rain were run to evaluate the mobility of F and the impact of weathering on native bacterial community composition in PG. After a simulated summer rainfall, 2.42-3.05 wt% of the total F content of PG was leached and the F concentration in leachate was above the quality standard for surface water and groundwater in China. Acid rain had no significant effect on the movement of F in PG. A higher concentration of F was observed at the bottom than the top section of PG columns suggesting mobility and reprecipitation of F. Throughout the simulation, the PG was environmentally safe according the TCLP testing. The dominant bacteria in PG were from the Enterococcus and Bacillus genus. Bacterial community composition in PG leached by simulated acid rain (pH 3.03) was more abundant than at pH 6.88. Information on F mobility and bacterial community in PG under conditions of simulated rain is relevant to management of environmental risk in stockpiled PG waste.

Nucleic acid-binding glycoproteins which solubilize nucleic acids in dilute acid: re-examination of the Ustilago maydis glycoproteins

Energy Technology Data Exchange (ETDEWEB)

Unrau, P.; Champ, D.R.; Young, J.L.; Grant, C.E.

1980-01-01

Holloman reported the isolation from Ustilago maydis of a glycoprotein which prevented the precipitation of nucleic acids in cold 5% trichloroacetic acid. Two glycoprotein fractions from U. maydis with this nucleic acid-solubilizing activity were isolated in our laboratory using improved purification procedures. The activity was not due to nuclease contamination. The glycoproteins are distinguished by: their ability to bind to concanavalin A-Sepharose; their differential binding to double- and single-stranded deoxyribonucleic acid, and to ribonucleic acid; their molecular weights (46,000 and 69,000); and the relative amounts present in growing versus nongrowing cells. Both fractions required sulfhydryl-reducing conditions for optimal yields, specific activity, and stability. Nucleic acid binding was cooperative, the minimum number of glycoproteins required to make a native T7 DNA molecule soluble in dilute acid being estimated at 2 and 15, respectively.

Diverse Bacterial PKS Sequences Derived From Okadaic Acid-Producing Dinoflagellates

Directory of Open Access Journals (Sweden)

Kathleen S. Rein

2008-05-01

Full Text Available Okadaic acid (OA and the related dinophysistoxins are isolated from dinoflagellates of the genus Prorocentrum and Dinophysis. Bacteria of the Roseobacter group have been associated with okadaic acid producing dinoflagellates and have been previously implicated in OA production. Analysis of 16S rRNA libraries reveals that Roseobacter are the most abundant bacteria associated with OA producing dinoflagellates of the genus Prorocentrum and are not found in association with non-toxic dinoflagellates. While some polyketide synthase (PKS genes form a highly supported Prorocentrum clade, most appear to be bacterial, but unrelated to Roseobacter or Alpha-Proteobacterial PKSs or those derived from other Alveolates Karenia brevis or Crytosporidium parvum.

Effects of jasmonic acid, ethylene, and salicylic acid signaling on the rhizosphere bacterial community of Arabidopsis thaliana.

Science.gov (United States)

Doornbos, Rogier F; Geraats, Bart P J; Kuramae, Eiko E; Van Loon, L C; Bakker, Peter A H M

2011-04-01

Systemically induced resistance is a promising strategy to control plant diseases, as it affects numerous pathogens. However, since induced resistance reduces one or both growth and activity of plant pathogens, the indigenous microflora may also be affected by an enhanced defensive state of the plant. The aim of this study was to elucidate how much the bacterial rhizosphere microflora of Arabidopsis is affected by induced systemic resistance (ISR) or systemic acquired resistance (SAR). Therefore, the bacterial microflora of wild-type plants and plants affected in their defense signaling was compared. Additionally, ISR was induced by application of methyl jasmonate and SAR by treatment with salicylic acid or benzothiadiazole. As a comparative model, we also used wild type and ethylene-insensitive tobacco. Some of the Arabidopsis genotypes affected in defense signaling showed altered numbers of culturable bacteria in their rhizospheres; however, effects were dependent on soil type. Effects of plant genotype on rhizosphere bacterial community structure could not be related to plant defense because chemical activation of ISR or SAR had no significant effects on density and structure of the rhizosphere bacterial community. These findings support the notion that control of plant diseases by elicitation of systemic resistance will not significantly affect the resident soil bacterial microflora.

Analysis of Bacterial Diversity During Acetic Acid Fermentation of Tianjin Duliu Aged Vinegar by 454 Pyrosequencing.

Science.gov (United States)

Peng, Qian; Yang, Yanping; Guo, Yanyun; Han, Ye

2015-08-01

The vinegar pei harbors complex bacterial communities. Prior studies revealing the bacterial diversity involved were mainly conducted by culture-dependent methods and PCR-DGGE. In this study, 454 pyrosequencing was used to investigate the bacterial communities in vinegar pei during the acetic acid fermentation (AAF) of Tianjin Duliu aged vinegar (TDAV). The results showed that there were 7 phyla and 24 families existing in the vinegar pei, with 2 phyla (Firmicutes, Protebacteria) and 4 families (Lactobacillaceae, Acetobacteracae, Enterobacteriaceae, Chloroplast) predominating. The genus-level identification revealed that 9 genera were the relatively stable, consistent components in different stages of AAF, including the most abundant genus Lactobacillus followed by Acetobacter and Serratia. Additionally, the bacterial community in the early fermentation stage was more complex than those in the later stages, indicating that the accumulation of organic acids provided an appropriate environment to filter unwanted bacteria and to accelerate the growth of required ones. This study provided basic information of bacterial patterns in vinegar pei and relevant changes during AAF of TDAV, and could be used as references in the following study on the implementation of starter culture as well as the improvement of AAF process.

Bacterial metabolism of human polymorphonuclear leukocyte-derived arachidonic acid.

Science.gov (United States)

Sorrell, T C; Muller, M; Sztelma, K

1992-05-01

Evidence for transcellular bacterial metabolism of phagocyte-derived arachidonic acid was sought by exposing human blood polymorphonuclear leukocytes, prelabelled with [3H]arachidonic acid, to opsonized, stationary-phase Pseudomonas aeruginosa (bacteria-to-phagocyte ratio of 50:1) for 90 min at 37 degrees C. Control leukocytes were stimulated with the calcium ionophore A23187 (5 microM) for 5 min. Radiochromatograms of arachidonic acid metabolites, extracted from A23187-stimulated cultures and then separated by reverse-phase high-performance liquid chromatography, revealed leukotriene B4, its omega-oxidation products, and 5-hydroxy-eicosatetraenoic acid. In contrast, two major metabolite peaks, distinct from known polymorphonuclear leukocyte arachidonic acid products by high-performance liquid chromatography or by thin-layer chromatography, were identified in cultures of P. aeruginosa with [3H]arachidonic acid-labelled polymorphonuclear leukocytes. Respective chromatographic characteristics of these novel products were identical to those of two major metabolite peaks produced by incubation of stationary-phase P. aeruginosa with [3H]arachidonic acid. Production of the metabolites was dependent upon pseudomonal viability. UV spectral data were consistent with a conjugated diene structure. Metabolism of arachidonic acid by P. aeruginosa was not influenced by the presence of catalase, superoxide dismutase, nordihydroguaiaretic acid, ethanol, dimethyl sulfoxide, or ferrous ions but was inhibited by carbon monoxide, ketoconazole, and 1,2-epoxy-3,3,3-trichloropropane. Our data suggest that pseudomonal metabolism of polymorphonuclear leukocyte-derived arachidonic acid occurs during phagocytosis, probably by enzymatic epoxidation and hydroxylation via an oxygenase. By this means, potential proinflammatory effects of arachidonic acid or its metabolites may be modulated by P. aeruginosa at sites of infection in vivo.

Characterization of a novel sialic acid transporter of the sodium solute symporter (SSS) family and in vivo comparison with known bacterial sialic acid transporters.

Science.gov (United States)

Severi, Emmanuele; Hosie, Arthur H F; Hawkhead, Judith A; Thomas, Gavin H

2010-03-01

The function of sialic acids in the biology of bacterial pathogens is reflected by the diverse range of solute transporters that can recognize these sugar acids. Here, we use an Escherichia coliDeltananT strain to characterize the function of known and proposed bacterial sialic acid transporters. We discover that the STM1128 gene from Salmonella enterica serovar Typhimurium, which encodes a member of the sodium solute symporter family, is able to restore growth on sialic acid to the DeltananT strain and is able to transport [(14)C]-sialic acid. Using the DeltananT genetic background, we performed a direct in vivo comparison of the transport properties of the STM1128 protein with those of sialic acid transporters of the major facilitator superfamily and tripartite ATP-independent periplasmic families, E. coli NanT and Haemophilus influenzae SiaPQM, respectively. This revealed that both STM1128 and SiaPQM are sodium-dependent and, unlike SiaPQM, both STM1128 and NanT are reversible secondary carriers, demonstrating qualitative functional differences in the properties of sialic acid transporters used by bacteria that colonize humans.

Soil factors involved in the diversity and structure of soil bacterial communities in commercial organic olive orchards in Southern Spain.

Science.gov (United States)

Landa, B B; Montes-Borrego, M; Aranda, S; Soriano, M A; Gómez, J A; Navas-Cortés, J A

2014-04-01

Nowadays, there is a tendency in olive production systems to reduce tillage or keep a vegetative cover to reduce soil erosion and degradation. However, there is scarce information on the effects of different soil management systems (SMS) in soil bacterial community composition of olive groves. In this study, we have evaluated the effects of soil type and different SMS implemented to control weeds in the structure and diversity of bacterial communities of 58 soils in the two geographic areas that best represent the organic olive production systems in Spain. Bacterial community composition assessed by frequency and intensity of occurrence of terminal restriction profiles (TRFs) derived from terminal restriction fragment length polymorphism (T-RFLP) analysis of amplified 16S ribosomal deoxyribonucleic acid were strongly correlated with soil type/field site (Eutric/Calcaric) that differed mainly in soil particle size distribution and soil pH, followed by a strong effect of SMS, in that order. Canonical discriminant (CD) analysis of TRFs properly classified all of the olive orchard soils as belonging to their respective soil type or SMS. Furthermore, only a small set of TRFs were enough to clearly and significantly differentiate soil samples according to soil type or SMS. Those specific TRFs could be used as bioindicators to assess the effect of changes in SMS aimed to enhance soil quality in olive production systems. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

Glyphosate has limited short-term effects on commensal bacterial community composition in the gut environment due to sufficient aromatic amino acid levels.

Science.gov (United States)

Nielsen, Lene Nørby; Roager, Henrik M; Casas, Mònica Escolà; Frandsen, Henrik L; Gosewinkel, Ulrich; Bester, Kai; Licht, Tine Rask; Hendriksen, Niels Bohse; Bahl, Martin Iain

2018-02-01

Recently, concerns have been raised that residues of glyphosate-based herbicides may interfere with the homeostasis of the intestinal bacterial community and thereby affect the health of humans or animals. The biochemical pathway for aromatic amino acid synthesis (Shikimate pathway), which is specifically inhibited by glyphosate, is shared by plants and numerous bacterial species. Several in vitro studies have shown that various groups of intestinal bacteria may be differently affected by glyphosate. Here, we present results from an animal exposure trial combining deep 16S rRNA gene sequencing of the bacterial community with liquid chromatography mass spectrometry (LC-MS) based metabolic profiling of aromatic amino acids and their downstream metabolites. We found that glyphosate as well as the commercial formulation Glyfonova ® 450 PLUS administered at up to fifty times the established European Acceptable Daily Intake (ADI = 0.5 mg/kg body weight) had very limited effects on bacterial community composition in Sprague Dawley rats during a two-week exposure trial. The effect of glyphosate on prototrophic bacterial growth was highly dependent on the availability of aromatic amino acids, suggesting that the observed limited effect on bacterial composition was due to the presence of sufficient amounts of aromatic amino acids in the intestinal environment. A strong correlation was observed between intestinal concentrations of glyphosate and intestinal pH, which may partly be explained by an observed reduction in acetic acid produced by the gut bacteria. We conclude that sufficient intestinal levels of aromatic amino acids provided by the diet alleviates the need for bacterial synthesis of aromatic amino acids and thus prevents an antimicrobial effect of glyphosate in vivo. It is however possible that the situation is different in cases of human malnutrition or in production animals. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Comparison of Cultivable Acetic Acid Bacterial Microbiota in Organic and Conventional Apple Cider Vinegar

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Aleksandra Štornik

2016-01-01

Full Text Available Organic apple cider vinegar is produced from apples that go through very restricted treatment in orchard. During the first stage of the process, the sugars from apples are fermented by yeasts to cider. The produced ethanol is used as a substrate by acetic acid bacteria in a second separated bioprocess. In both, the organic and conventional apple cider vinegars the ethanol oxidation to acetic acid is initiated by native microbiota that survived alcohol fermentation. We compared the cultivable acetic acid bacterial microbiota in the production of organic and conventional apple cider vinegars from a smoothly running oxidation cycle of a submerged industrial process. In this way we isolated and characterized 96 bacteria from organic and 72 bacteria from conventional apple cider vinegar. Using the restriction analysis of the PCR-amplifi ed 16S-23S rRNA gene ITS regions, we identified four different HaeIII and five different HpaII restriction profiles for bacterial isolates from organic apple cider vinegar. Each type of restriction profile was further analyzed by sequence analysis of the 16S-23S rRNA gene ITS regions, resulting in identification of the following species: Acetobacter pasteurianus (71.90 %, Acetobacter ghanensis (12.50 %, Komagataeibacter oboediens (9.35 % and Komagataeibacter saccharivorans (6.25 %. Using the same analytical approach in conventional apple cider vinegar, we identified only two different HaeIII and two different HpaII restriction profiles of the 16S‒23S rRNA gene ITS regions, which belong to the species Acetobacter pasteurianus (66.70 % and Komagataeibacter oboediens (33.30 %. Yeasts that are able to resist 30 g/L of acetic acid were isolated from the acetic acid production phase and further identified by sequence analysis of the ITS1-5.8S rDNA‒ITS2 region as Candida ethanolica, Pichia membranifaciens and Saccharomycodes ludwigii. This study has shown for the first time that the bacterial microbiota for the

Comparison of Cultivable Acetic Acid Bacterial Microbiota in Organic and Conventional Apple Cider Vinegar.

Science.gov (United States)

Štornik, Aleksandra; Skok, Barbara; Trček, Janja

2016-03-01

Organic apple cider vinegar is produced from apples that go through very restricted treatment in orchard. During the first stage of the process, the sugars from apples are fermented by yeasts to cider. The produced ethanol is used as a substrate by acetic acid bacteria in a second separated bioprocess. In both, the organic and conventional apple cider vinegars the ethanol oxidation to acetic acid is initiated by native microbiota that survived alcohol fermentation. We compared the cultivable acetic acid bacterial microbiota in the production of organic and conventional apple cider vinegars from a smoothly running oxidation cycle of a submerged industrial process. In this way we isolated and characterized 96 bacteria from organic and 72 bacteria from conventional apple cider vinegar. Using the restriction analysis of the PCR-amplified 16S-23S rRNA gene ITS regions, we identified four different Hae III and five different Hpa II restriction profiles for bacterial isolates from organic apple cider vinegar. Each type of restriction profile was further analyzed by sequence analysis of the 16S-23S rRNA gene ITS regions, resulting in identification of the following species: Acetobacter pasteurianus (71.90%), Acetobacter ghanensis (12.50%), Komagataeibacter oboediens (9.35%) and Komagataeibacter saccharivorans (6.25%). Using the same analytical approach in conventional apple cider vinegar, we identified only two different Hae III and two different Hpa II restriction profiles of the 16S‒23S rRNA gene ITS regions, which belong to the species Acetobacter pasteurianus (66.70%) and Komagataeibacter oboediens (33.30%). Yeasts that are able to resist 30 g/L of acetic acid were isolated from the acetic acid production phase and further identified by sequence analysis of the ITS1-5.8S rDNA‒ITS2 region as Candida ethanolica , Pichia membranifaciens and Saccharomycodes ludwigii . This study has shown for the first time that the bacterial microbiota for the industrial production of

Characterization and purification of a bacterial chlorogenic acid esterase detected during the extraction of chlorogenic acid from arbuscular mycorrhizal tomato roots.

Science.gov (United States)

Negrel, Jonathan; Javelle, Francine; Morandi, Dominique; Lucchi, Géraldine

2016-12-01

A Gram-negative bacterium able to grow using chlorogenic acid (5-caffeoylquinic acid) as sole carbon source has been isolated from the roots of tomato plants inoculated with the arbuscular mycorrhizal fungus Rhizophagus irregularis. An intracellular esterase exhibiting very high affinity (K m  = 2 μM) for chlorogenic acid has been extracted and purified by FPLC from the chlorogenate-grown cultures of this bacterium. The molecular mass of the purified esterase determined by SDS-PAGE was 61 kDa and its isoelectric point determined by chromatofocusing was 7.75. The esterase hydrolysed chlorogenic acid analogues (caffeoylshikimate, and the 4- and 3-caffeoylquinic acid isomers), feruloyl esterases substrates (methyl caffeate and methyl ferulate), and even caffeoyl-CoA in vitro but all of them were less active than chlorogenic acid, demonstrating that the esterase is a genuine chlorogenic acid esterase. It was also induced when the bacterial strain was cultured in the presence of hydroxycinnamic acids (caffeic, p-coumaric or ferulic acid) as sole carbon source, but not in the presence of simple phenolics such as catechol or protocatechuic acid, nor in the presence of organic acids such as succinic or quinic acids. The purified esterase was remarkably stable in the presence of methanol, rapid formation of methyl caffeate occurring when its activity was measured in aqueous solutions containing 10-60% methanol. Our results therefore show that this bacterial chlorogenase can catalyse the transesterification reaction previously detected during the methanolic extraction of chlorogenic acid from arbuscular mycorrhizal tomato roots. Data are presented suggesting that colonisation by Rhizophagus irregularis could increase chlorogenic acid exudation from tomato roots, especially in nutrient-deprived plants, and thus favour the growth of chlorogenate-metabolizing bacteria on the root surface or in the mycorhizosphere. Copyright © 2016 Elsevier Masson SAS. All rights

In Silico Phylogenetic Analysis and Molecular Modelling Study of 2-Haloalkanoic Acid Dehalogenase Enzymes from Bacterial and Fungal Origin

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Raghunath Satpathy

2016-01-01

Full Text Available 2-Haloalkanoic acid dehalogenase enzymes have broad range of applications, starting from bioremediation to chemical synthesis of useful compounds that are widely distributed in fungi and bacteria. In the present study, a total of 81 full-length protein sequences of 2-haloalkanoic acid dehalogenase from bacteria and fungi were retrieved from NCBI database. Sequence analysis such as multiple sequence alignment (MSA, conserved motif identification, computation of amino acid composition, and phylogenetic tree construction were performed on these primary sequences. From MSA analysis, it was observed that the sequences share conserved lysine (K and aspartate (D residues in them. Also, phylogenetic tree indicated a subcluster comprised of both fungal and bacterial species. Due to nonavailability of experimental 3D structure for fungal 2-haloalkanoic acid dehalogenase in the PDB, molecular modelling study was performed for both fungal and bacterial sources of enzymes present in the subcluster. Further structural analysis revealed a common evolutionary topology shared between both fungal and bacterial enzymes. Studies on the buried amino acids showed highly conserved Leu and Ser in the core, despite variation in their amino acid percentage. Additionally, a surface exposed tryptophan was conserved in all of these selected models.

Inhibitors of bacterial N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) and demonstration of in vitro antimicrobial activity.

Science.gov (United States)

Gillner, Danuta; Armoush, Nicola; Holz, Richard C; Becker, Daniel P

2009-11-15

The dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) is a critical bacterial enzyme for the construction of the bacterial cell wall. A screen biased toward compounds containing zinc-binding groups (ZBG's) including thiols, carboxylic acids, boronic acids, phosphonates and hydroxamates has delivered a number of micromolar inhibitors of DapE from Haemophilus influenzae, including the low micromolar inhibitor L-captopril (IC(50)=3.3 microM, K(i)=1.8 microM). In vitro antimicrobial activity was demonstrated for L-captopril against Escherichia coli.

Bacterial dynamics and metabolite changes in solid-state acetic acid fermentation of Shanxi aged vinegar.

Science.gov (United States)

Li, Sha; Li, Pan; Liu, Xiong; Luo, Lixin; Lin, Weifeng

2016-05-01

Solid-state acetic acid fermentation (AAF), a natural or semi-controlled fermentation process driven by reproducible microbial communities, is an important technique to produce traditional Chinese cereal vinegars. Highly complex microbial communities and metabolites are involved in traditional Chinese solid-state AAF, but the association between microbiota and metabolites during this process are still poorly understood. In this study, we performed amplicon 16S rRNA gene sequencing on the Illumina MiSeq platform, PCR-denaturing gradient gel electrophoresis, and metabolite analysis to trace the bacterial dynamics and metabolite changes under AAF process. A succession of bacterial assemblages was observed during the AAF process. Lactobacillales dominated all the stages. However, Acetobacter species in Rhodospirillales were considerably accelerated during AAF until the end of fermentation. Quantitative PCR results indicated that the biomass of total bacteria showed a "system microbe self-domestication" process in the first 3 days, and then peaked at the seventh day before gradually decreasing until the end of AAF. Moreover, a total of 88 metabolites, including 8 organic acids, 16 free amino acids, and 66 aroma compounds were detected during AAF. Principal component analysis and cluster analyses revealed the high correlation between the dynamics of bacterial community and metabolites.

Karyotype and nucleic acid content in Zantedeschia aethiopica Spr ...

African Journals Online (AJOL)

DR. NJ TONUKARI

2012-07-03

Jul 3, 2012 ... Analysis of karyotype, nucleic deoxyribonucleic acid (DNA) content and sodium dodecyl sulfate polyacrylamide ... base pairs) for Z. aethiopica and 1144.26 ± 0.05 picograms (equivalent to 1144.26 mega base pairs) for Z. elliottiana. ... ml ice-cold nuclei-isolation buffer A of the Partec high resolution. DNA kit ...

Structural Characterisation of FabG from Yersinia pestis, a Key Component of Bacterial Fatty Acid Synthesis.

Science.gov (United States)

Nanson, Jeffrey D; Forwood, Jade K

2015-01-01

Ketoacyl-acyl carrier protein reductases (FabG) are ubiquitously expressed enzymes that catalyse the reduction of acyl carrier protein (ACP) linked thioesters within the bacterial type II fatty acid synthesis (FASII) pathway. The products of these enzymes, saturated and unsaturated fatty acids, are essential components of the bacterial cell envelope. The FASII reductase enoyl-ACP reductase (FabI) has been the focus of numerous drug discovery efforts, some of which have led to clinical trials, yet few studies have focused on FabG. Like FabI, FabG appears to be essential for survival in many bacteria, similarly indicating the potential of this enzyme as a drug target. FabG enzymes are members of the short-chain alcohol dehydrogenase/reductase (SDR) family, and like other SDRs, exhibit highly conserved secondary and tertiary structures, and contain a number of conserved sequence motifs. Here we describe the crystal structures of FabG from Yersinia pestis (YpFabG), the causative agent of bubonic, pneumonic, and septicaemic plague, and three human pandemics. Y. pestis remains endemic in many parts of North America, South America, Southeast Asia, and Africa, and a threat to human health. YpFabG shares a high degree of structural similarity with bacterial homologues, and the ketoreductase domain of the mammalian fatty acid synthase from both Homo sapiens and Sus scrofa. Structural characterisation of YpFabG, and comparison with other bacterial FabGs and the mammalian fatty acid synthase, provides a strong platform for virtual screening of potential inhibitors, rational drug design, and the development of new antimicrobial agents to combat Y. pestis infections.

Structural Characterisation of FabG from Yersinia pestis, a Key Component of Bacterial Fatty Acid Synthesis.

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Jeffrey D Nanson

Full Text Available Ketoacyl-acyl carrier protein reductases (FabG are ubiquitously expressed enzymes that catalyse the reduction of acyl carrier protein (ACP linked thioesters within the bacterial type II fatty acid synthesis (FASII pathway. The products of these enzymes, saturated and unsaturated fatty acids, are essential components of the bacterial cell envelope. The FASII reductase enoyl-ACP reductase (FabI has been the focus of numerous drug discovery efforts, some of which have led to clinical trials, yet few studies have focused on FabG. Like FabI, FabG appears to be essential for survival in many bacteria, similarly indicating the potential of this enzyme as a drug target. FabG enzymes are members of the short-chain alcohol dehydrogenase/reductase (SDR family, and like other SDRs, exhibit highly conserved secondary and tertiary structures, and contain a number of conserved sequence motifs. Here we describe the crystal structures of FabG from Yersinia pestis (YpFabG, the causative agent of bubonic, pneumonic, and septicaemic plague, and three human pandemics. Y. pestis remains endemic in many parts of North America, South America, Southeast Asia, and Africa, and a threat to human health. YpFabG shares a high degree of structural similarity with bacterial homologues, and the ketoreductase domain of the mammalian fatty acid synthase from both Homo sapiens and Sus scrofa. Structural characterisation of YpFabG, and comparison with other bacterial FabGs and the mammalian fatty acid synthase, provides a strong platform for virtual screening of potential inhibitors, rational drug design, and the development of new antimicrobial agents to combat Y. pestis infections.

Lactic Acid Bacterial Starter Culture with Antioxidant and γ-Aminobutyric Acid Biosynthetic Activities Isolated from Flatfish-Sikhae Fermentation.

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Won, Yeong Geol; Yu, Hyun-Hee; Chang, Young-Hyo; Hwang, Han-Joon

2015-12-01

The aim of this study is to select a lactic acid bacterial strain as a starter culture for flatfish-Sikhae fermentation and to evaluate its suitability for application in a food system. Four strains of lactic acid bacteria isolated from commercial flatfish-Sikhae were identified and selected as starter culture candidates through investigation of growth rates, salt tolerance, food safety, and functional properties such as antioxidative and antimicrobial activities. The fermentation properties of the starter candidates were also examined in food systems prepared with these strains (candidate batch) in comparison with a spontaneous fermentation process without starter culture (control batch) at 15°C. The results showed that the candidate YG331 batch had better fermentation properties such as viable cell count, pH, and acidity than the other experimental batches, including the control batch. The results are expressed according to selection criteria based on a preliminary sensory evaluation and physiochemical investigation. Also, only a small amount of histamine was detected with the candidate YG331 batch. The radical scavenging activity of the candidate batches was better compared with the control batch, and especially candidate YG331 batch showed the best radical scavenging activity. Also, we isolated another starter candidate (identified as Lactobacillus brevis PM03) with γ-aminobutyric acid (GABA)-producing activity from commercial flatfish-Sikhae products. The sensory scores of the candidate YG331 batch were better than those of the other experimental batches in terms of flavor, color, and overall acceptance. In this study, we established selection criteria for the lactic acid bacterial starter for the flatfish-Sikhae production and finally selected candidate YG331 as the most suitable starter.

Effects of remediation on the bacterial community of an acid mine drainage impacted stream.

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Ghosh, Suchismita; Moitra, Moumita; Woolverton, Christopher J; Leff, Laura G

2012-11-01

Acid mine drainage (AMD) represents a global threat to water resources, and as such, remediation of AMD-impacted streams is a common practice. During this study, we examined bacterial community structure and environmental conditions in a low-order AMD-impacted stream before, during, and after remediation. Bacterial community structure was examined via polymerase chain reaction amplification of 16S rRNA genes followed by denaturing gradient gel electrophoresis. Also, bacterial abundance and physicochemical data (including metal concentrations) were collected and relationships to bacterial community structure were determined using BIO-ENV analysis. Remediation of the study stream altered environmental conditions, including pH and concentrations of some metals, and consequently, the bacterial community changed. However, remediation did not necessarily restore the stream to conditions found in the unimpacted reference stream; for example, bacterial abundances and concentrations of some elements, such as sulfur, magnesium, and manganese, were different in the remediated stream than in the reference stream. BIO-ENV analysis revealed that changes in pH and iron concentration, associated with remediation, primarily explained temporal alterations in bacterial community structure. Although the sites sampled in the remediated stream were in relatively close proximity to each other, spatial variation in community composition suggests that differences in local environmental conditions may have large impacts on the microbial assemblage.

Skin bacterial flora as a potential risk factor predisposing to late bacterial infection after cross-linked hyaluronic acid gel augmentation.

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Netsvyetayeva, Irina; Marusza, Wojciech; Olszanski, Romuald; Szyller, Kamila; Krolak-Ulinska, Aneta; Swoboda-Kopec, Ewa; Sierdzinski, Janusz; Szymonski, Zachary; Mlynarczyk, Grazyna

2018-01-01

Cross-linked hyaluronic acid (HA) gel is widely used in esthetic medicine. Late bacterial infection (LBI) is a rare, but severe complication after HA augmentation. The aim of this study was to determine whether patients who underwent the HA injection procedure and developed LBI had qualitatively different bacterial flora on the skin compared to patients who underwent the procedure without any complications. The study group comprised 10 previously healthy women with recently diagnosed, untreated LBI after HA augmentation. The control group comprised 17 healthy women who had a similar amount of HA injected with no complications. To assess the difference between the two groups, their skin flora was cultured from nasal swabs, both before and after antibiotic treatment in the study group. A significant increase in the incidence of Staphylococcus epidermidis was detected in the control group ( P =0.000) compared to the study group. The study group showed a significantly higher incidence of Staphylococcus aureus ( P =0.005), Klebsiella pneumoniae ( P =0.006), Klebsiella oxytoca ( P =0.048), and Staphylococcus haemolyticus ( P =0.048) compared to the control group. The bacterial flora on the skin differed in patients with LBI from the control group. The control group's bacterial skin flora was dominated by S. epidermidis . Patients with LBI had a bacterial skin flora dominated by potentially pathogenic bacteria.

Short chain and polyunsaturated fatty acids in host gut health and foodborne bacterial pathogen inhibition.

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Peng, Mengfei; Biswas, Debabrata

2017-12-12

As a major source of microbes and their numerous beneficial effects, the gut microflora/microbiome is intimately linked to human health and disease. The exclusion of enteric pathogens by these commensal microbes partially depends upon the production of bioactive compounds such as short-chain fatty acids (SCFAs) and polyunsaturated fatty acids (PUFAs). These key intestinal microbial byproducts are crucial to the maintenance of a healthy gut microbial community. Moreover, SCFAs and PUFAs play multiple critical roles in host defense and immunity, including anti-cancer, anti-inflammation, and anti-oxidant activities, as well as out-competition of enteric bacterial pathogens. In this review article, we hereby aim to highlight the importance of SCFAs and PUFAs and the microbes involved in production of these beneficial intestinal components, and their biological functions, specifically as to their immunomodulation and interactions with enteric bacterial pathogens. Finally, we also advance potential applications of these fatty acids with regards to food safety and human gut health.

Analysis of the Cellular and Molecular Mechanisms Which Underlie Sensitivity to Bacterial Endotoxin and Early Tolerance

Science.gov (United States)

1992-06-24

hydrolase enzyme bp- base pairs BSA- bovine serum albumin cAMP- cyclic adenosine S’-monophosphate cDNA- complementary deoxyribonucleic acid C02...tachycardia, tachypnea, hypertriglyceridemia, thrombocytopenia, metabolic acidosis , acute renal failure, hepatic failure, acute respiratory distress...bilirubin, lactate (which indicates an ameliorating effect on metabolic acidosis ), and to bring about an increase in the mean arterial pressure in balxxms

Effect of lactic acid suppositories compared with oral metronidazole and placebo in bacterial vaginosis: a randomised clinical trial.

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Boeke, A J; Dekker, J H; van Eijk, J T; Kostense, P J; Bezemer, P D

1993-01-01

OBJECTIVE--To compare the effect of lactic acid locally, metronidazole orally and placebo in women with bacterial vaginosis. DESIGN--Randomised clinical trial. SETTING--30 general practices in the Netherlands. PATIENTS--125 women consulting the general practitioner for symptomatic bacterial vaginosis. MAIN OUTCOME MEASURES--Duration of subjective symptoms, recurrence of symptoms, clinically diagnosed cure, adverse events. RESULTS--Survival analysis showed a significantly faster disappearance of symptoms in the metronidazole category compared with both lactic acid and placebo (p = 0.0005 metronidazole v placebo, p = 0.0002 metronidazole v lactic acid p = 0.6521 lactic acid v placebo [The stratified Mantel Cox test]). The median duration until absence of symptoms was 21 days for metronidazole and 80 days for placebo. Disappearance of symptoms did not occur in 50% of the lactic acid group in 90 days. Recurrence rates of symptoms were similar over the treatment categories (p = 0.13 metronidazole v placebo and p = 0.12 lactic acid v placebo). After 2 weeks cure rates (cure defined as less than three of four clinical criteria present) were 83%, 49% and 47% for metronidazole, lactic acid and placebo category respectively. At that time cure rates (cure defined as none of three clinical criteria present) were 10%, 0% and 3%. After four weeks and three months these figures were: 55%, 20%, 20% and 64%, 28%, 28%. No differences in adverse events were found between the three interventions. CONCLUSIONS--Lactic acid suppositories are ineffective, metronidazole capsules are effective on signs and symptoms in bacterial vaginosis. A considerable proportion of the patients recover without active medication. PMID:8244360

Striking similarities are exhibited by two small Epstein-Barr virus-encoded ribonucleic acids and the adenovirus-associated ribonucleic acids VAI and VAII

Energy Technology Data Exchange (ETDEWEB)

Rosa, M.D.; Gottlieb, E.; Lerner, M.R.; Steitz, J.A.

1981-09-01

The nucleotide sequence of the region of the Epstein-Barr virus genome that specified two small ribonucleic acids (RNAs), EBER 1 and EBER 2, has been determined. Both of these RNAs are encoded by the right-hand 1,000 base pairs of the EcoRI J fragment of EBV deoxyribonucleic acid. EBER 1 is 166 (167) nucleotides long and EBER 2 is 172 +- 1 nucleotides long; the heterogeneity resides at the 3' termini. The EBER genes are separated by 161 base pairs and are transcribed from the same deoxyribonucleic acid strand. In vitro, both EBER genes can be transcribed by RNA polymerase III; sequences homologous to previously identified RNA polymerase III intragenic transcription control regions are present. Striking similarities are therefore apparent both between the EBERs and the two adenovirus-associated RNAs, VAI and VAII, and between the regions of the two viral genomes that specify these small RNAs. We have shown that VAII RNA as well as VAI RNA and the EBERs exist in ribonucleoprotein complexes which are precipitable by anti-La antibodies associated with systemic lupus erythematosus. Finally the authors have demonstrated that the binding of protein(s) from uninfected cells confers antigenicity on each of the four virus-encoded small RNAs.

Potent Antioxidative Activity of Lycopene: A Potential Role in Scavenging Hypochlorous Acid †

OpenAIRE

Pennathur, Subramaniam; Maitra, Dhiman; Byun, Jaeman; Sliskovic, Inga; Abdulhamid, Ibrahim; Saed, Ghassan M.; Diamond, Michael P.; Abu-Soud, Husam M.

2010-01-01

Lycopene, a carotenoid found in tomatoes, is a proven anti-oxidant that may lower the risk of certain disorders including heart disease and cancer. Hypochlorous acid (HOCl) is an oxidant linked to tissue oxidation in cardiovascular disease and other inflammatory disorders through its ability to modify proteins, deoxyribonucleic acid, ribonucleic acid and lipids. Here we show that lycopene can function as a potent scavenger of HOCl at a wide range of concentrations that span various pathophysi...

Development of a bacterial bioassay for atrazine and cyanuric acid detection

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Anna eHUA

2015-03-01

Full Text Available The s-triazine herbicides are compounds which can disseminate into soils and water. Due to their toxic effects on living organisms, their concentrations in drinking water are legislated by WHO recommendations. Here we have developed for the first time, to the best of our knowledge, an alternative method for physicochemical quantification using two bioluminescent bacterial biosensors: E. coli SM003 for cyanuric acid detection and E. coli SM004 for both atrazine and cyanuric acid detection. The concentration of cyanuric acid detection for E. coli SM003 ranges from 7.83 µM to 2.89 mM, and for E. coli SM004 ranges from 0.22 µM to 15 µM. Moreover, atrazine detection by E. coli SM004 ranges from 1.08 µM to 15 µM. According to WHO recommendations, the cyanuric acid detection range is sensitive enough to discriminate between polluted and drinking water. Nevertheless, the detection of atrazine by E. coli SM004 is only applicable for high concentrations of contaminants.

Bacterial Oxidation and Reduction of Iron in the Processes of Creation and Treatment of Acid Mining Waters

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Daniel Kupka

2004-12-01

Full Text Available Acid mine drainages (AMDs arise at the weathering of sulphidic minerals. The occurrence of acidic streams is commonly associated with the human mining activities. Due to the disruption and excavation of sulphide deposits, the oxidation processes have initiated. Acidic products of sulphide oxidation accelerate the degradation of accompanying minerals. AMDs typically contain high concentrations of sulfuric acid and soluble metals and cause serious ecological problems due to the water pollution and the devastation of adjacent country. Microbial life in these extremely acidic environments may be considerably diverse. AMDs are abundant in bacteria capable to oxidize and/or to reduce iron. The rate of bacterial oxidation of ferrous iron released from pyrite surfaces is up to one million times faster than the chemical oxidation rate at low pH. Bacterial regeneration of ferric iron maintains the continuity of pyrite oxidation and the production of AMDs. Another group of microorganisms living in these environments are acidophilic ferric iron reducing bacteria. This group of microorganisms has been discovered only relatively recently. Acidophilic heterotrophic bacteria reduce ferric iron in either soluble or solid forms to ferrous iron. The reductive dissolution of ferric iron minerals brings about a mobilization of iron as well as associated heavy metals. The Bacterial oxidation and reduction of iron play an important role in the transformation of either crystalline or amorphous iron-containing minerals, including sulphides, oxides, hydroxysulfates, carbonates and silicates. This work discusses the role of acidophilic bacteria in the natural iron cycling and the genesis of acidic effluents. The possibilities of application of iron bacteria in the remediation of AMDs are also considered.

Nucleic Acid-based Detection of Bacterial Pathogens Using Integrated Microfluidic Platform Systems

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Carl A. Batt

2009-05-01

Full Text Available The advent of nucleic acid-based pathogen detection methods offers increased sensitivity and specificity over traditional microbiological techniques, driving the development of portable, integrated biosensors. The miniaturization and automation of integrated detection systems presents a significant advantage for rapid, portable field-based testing. In this review, we highlight current developments and directions in nucleic acid-based micro total analysis systems for the detection of bacterial pathogens. Recent progress in the miniaturization of microfluidic processing steps for cell capture, DNA extraction and purification, polymerase chain reaction, and product detection are detailed. Discussions include strategies and challenges for implementation of an integrated portable platform.

Combined Effects of Tauroursodeoxycholic Acid and Glutamine on Bacterial Translocation in Obstructive Jaundiced Rats

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Ahmet Rahmi Hatipoğlu

2013-12-01

Full Text Available Background: Bacterial Translocation is believed to be an important factor on mortality and morbidity in Obstructive Jaundiced. Aims: We investigated the probable or estimated positive effects of tauroursodeoxycholic acid, which has antibacterial and regulatory effects on intestinal flora, together with glutamine on BT in an experimental obstructive jaundiced rat model. Study Design: Animal experimentation. Methods: Forty adult, male, Sprague Dawley rats were used in this study. Animals were randomised and divided into five groups of eight each: sham (Sh; control (common bile duct ligation, CBDL; and supplementation groups administered tauroursodeoxycholic acid (CBDL+T, glutamine (CBDL+G, or tauroursodeoxycholic acid plus glutamine (CBDL+TG. Blood and liver, spleen, MLN, and ileal samples were taken via laparotomy under sterile conditions for investigation of bacterial translocation and intestinal mucosal integrity and hepatic function tests on the tenth postoperative day. Results: There were statistically significant differences in BT rates in all samples except the spleen of the CBDL+TG group compared with the CBDL group (p=0.041, p=0.026, and p=0.041, respectively. Conclusion: It is essential to protect hepatic functions besides maintaining intestinal mucosal integrity in the active struggle against BT occurring in obstructive jaundice. The positive effect on intestinal mucosal integrity can be increased if glutamine is used with tauroursodeoxycholic acid, which also has hepatoprotective and immunomodulatory features.

Changes in ruminal bacterial community composition following feeding of alfalfa ensiled with a lactic acid bacterial inoculant.

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Mohammed, R; Stevenson, D M; Beauchemin, K A; Muck, R E; Weimer, P J

2012-01-01

Some silage inoculants help to improve silage quality and promote an increase in milk production, possibly through altering the rumen microflora. We hypothesized that rumen bacterial community composition (BCC) would be different in cows fed alfalfa ensiled with the inoculant Lactobacillus plantarum MTD/1 (LP) compared with those fed alfalfa ensiled without the inoculant (Ctrl). Eight ruminally cannulated Holstein cows were allotted to 2 diets (Ctrl or LP) in a double crossover design with four 28-d periods. Diets were formulated to contain (% dry matter basis) 28.0% neutral detergent fiber and 16.2% crude protein, and contained alfalfa silage, 50.9; corn silage, 20.6; high-moisture shelled corn, 21.4; soy hulls, 4.7; plus minerals and vitamins, 2.4. Ruminal digesta were collected just before feeding on 3 consecutive days near the end of each period, and were separated into solid and liquid phases. Microbial DNA was extracted from each phase, amplified by PCR using domain-level bacterial primers, and subjected to automated ribosomal intergenic spacer analysis. The pH was 4.56 and 4.86 and the lactate-to-acetate ratio 9.8 and 4.4, respectively, for the treated and untreated alfalfa silages. Dry matter intakes and milk production data were not influenced by diets but showed a cow effect. Total volatile fatty acids (mM) tended to be greater for LP compared with Ctrl. Individual volatile fatty acids were not influenced by diets but showed a significant cow effect. Ruminal acetate (mol/100 mol) and acetate-to-propionate ratio were lower and propionate (mol/100 mol) greater for the 2 milk fat-depressed (MFD; content) cows compared with the other 6 cows. Correspondence analysis of the 265 peaks in the automated ribosomal intergenic spacer analysis profile across the 188 samples revealed that the first 2 components contributed 7.1 and 3.8% to the total variation in the profile. The ordination points representing the liquid and solid phases clustered separately, indicating

Rhizosphere bacterial carbon turnover is higher in nucleic acids than membrane lipids: implications for understanding soil carbon cycling

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Ashish A. Malik

2015-04-01

Full Text Available Using a pulse-chase 13CO2 plant labeling experiment we compared the flow of plant carbon into macromolecular fractions of root-associated soil microorganisms. Time dependent 13C dilution patterns in microbial cellular fractions were used to calculate their turnover time. The turnover times of microbial biomolecules were found to vary: microbial RNA (19 h and DNA (30 h turned over fastest followed by chloroform fumigation extraction-derived soluble cell lysis products (14 d, while phospholipid fatty acids (PLFAs had the slowest turnover (42 d. PLFA/NLFA 13C analyses suggest that both mutualistic arbuscular mycorrhizal and saprophytic fungi are dominant in initial plant carbon uptake. In contrast, high initial 13C enrichment in RNA hints at bacterial importance in initial C uptake due to the dominance of bacterial derived RNA in total extracts of soil RNA. To explain this discrepancy, we observed low renewal rate of bacterial lipids, which may therefore bias lipid fatty acid based interpretations of the role of bacteria in soil microbial food webs. Based on our findings, we question current assumptions regarding plant-microbe carbon flux and suggest that the rhizosphere bacterial contribution to plant assimilate uptake could be higher. This highlights the need for more detailed quantitative investigations with nucleic acid biomarkers to further validate these findings.

The Immediate and Delayed Post-Debridement Effects on Tissue Bacterial Wound Counts of Hypochlorous Acid Versus Saline Irrigation in Chronic Wounds.

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Hiebert, John M; Robson, Martin C

2016-01-01

Introduction: Wound debridement is considered essential in chronic wound management. Hypochlorous acid has been shown to be an effective agent in reducing wound bacterial counts in open wounds. Ultrasound-enabled wound debridement is an effective and efficient method of debridement. This study compared ultrasound irrigation with hypochlorous acid versus saline irrigation for wound debridement on pre- and postoperative wounds and determined regrowth of bacteria over 1 week period of time. Finally, the outcome of definitive wound closure of the clinically clean-appearing wounds was recorded. Methods: Seventeen consenting adult patients with chronic open wounds were randomly selected for study. The patients were randomly divided into the hypochlorous acid irrigation or saline irrigation group. All patients provided pre- and postoperative tissue samples for qualitative and quantitative bacteriology. For the time (7 days) between the debridement procedure and the definitive closure procedure, the wounds were dressed with a silver-impregnated dressing and a hydroconductive dressing. Results : Both types of irrigation in the ultrasonic system initially lowered the bacterial counts by 4 to 6 logs. However, by the time of definitive closure, the saline-irrigated wounds had bacterial counts back up to 10 5 whereas the hypochlorous acid-irrigated wounds remained at 10 2 or fewer. More than 80% of patients in the saline group had postoperative closure failure compared with 25% of patients in the hypochlorous acid group. Conclusions: Hypochlorous acid irrigation with ultrasound debridement reduced bacterial growth in chronic open wounds more efficiently than saline alone. Postoperative wound closure outcomes suggest a remarkable reduction in wound complications after wound debridement using hypochlorous acid irrigation with ultrasound versus saline alone.

Dietary supplementation with docosahexaenoic acid (DHA) improves seminal antioxidant status and decreases sperm DNA fragmentation.

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Martínez-Soto, Juan Carlos; Domingo, Joan Carles; Cordobilla, Begoña; Nicolás, María; Fernández, Laura; Albero, Pilar; Gadea, Joaquín; Landeras, José

2016-12-01

The purpose of this study was to evaluate the effect of docosahexaenoic acid (DHA) dietary supplementation on semen quality, fatty acid composition, antioxidant capacity, and DNA fragmentation. In this randomized, double blind, placebo-controlled, parallel-group study, 74 subjects were recruited and randomly assigned to either the placebo group (n=32) or to the DHA group (n=42) to consume three 500-mg capsules of oil per day over 10 weeks. The placebo group received 1,500 mg/day of sunflower oil and the DHA group 1,500 mg/day of DHA-enriched oil. Seminal parameters (semen volume, sperm concentration, motility, morphology, and vitality), total antioxidant capacity, deoxyribonucleic acid fragmentation, and lipid composition were evaluated prior to the treatment and after 10 weeks. Finally, 57 subjects were included in the study with 25 in the placebo group and 32 in the DHA group. No differences were found in traditional sperm parameters or lipid composition of the sperm membrane after treatment. However, an increase in DHA and Omega-3 fatty acid content in seminal plasma, an improvement in antioxidant status, and a reduction in the percentage of spermatozoa with deoxyribonucleic acid damage were observed in the DHA group after 10 weeks of treatment.

THE ROLE OF BACTERIAL SYMBIONTS IN AMINO ACID COMPOSITION OF BLACK BEAN APHIDS

Institute of Scientific and Technical Information of China (English)

MingGan; De-ChengDing; Xue-xiaMiao

2003-01-01

To evaluate the role of bacterial symbionts ( Buchnera spp. ) in the black bean aphids ( Aphis craccivora Koch), the aphids were treated with the antibiotic, rifampicin, to eliminate their intracellular symbiotic bacteria. Analysis of protein and amino acid concentration in 7-day-old of aposymbiotic aphids showed that the total protein content per mg fresh weight was significantly reduced by 29 %, but free amino acid titers were increased by 17% . The ratio of the essential amino acids was in general only around 20% essential amino acids in phloem sap of broad bean, whereas it was 44% and 37% in symbiotic and aposymbiotic aphids, respectively,suggesting that the composition of the free amino acids was unbalanced. For example, the essential amino acid,threonine represented 21. 6% of essential amino acids in symbiotic aphids, but it was only 16.7% in aposymbiotic aphids. Likewise, two nonessential amino acids, tyrosine and serine, represented 8.9% and 5.6% of total amino acids in symbiontic aphids, respectively, but they enhanced to 21.1% and 13.6% in aposymbiotic aphids. It seems likely that the elevated free amino acid concentration in aposymbiotic aphids was caused by the limited protein anabolism as the result of the unbalanced amino acid composition.

Effect of organic acids production and bacterial community on the possible mechanism of phosphorus solubilization during composting with enriched phosphate-solubilizing bacteria inoculation.

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Wei, Yuquan; Zhao, Yue; Shi, Mingzi; Cao, Zhenyu; Lu, Qian; Yang, Tianxue; Fan, Yuying; Wei, Zimin

2018-01-01

Enriched phosphate-solubilizing bacteria (PSB) agent were acquired by domesticated cultivation, and inoculated into kitchen waste composting in different stages. The effect of different treatments on organic acids production, tricalcium phosphate (TCP) solubilization and their relationship with bacterial community were investigated during composting. Our results pointed out that inoculation affected pH, total acidity and the production of oxalic, lactic, citric, succinic, acetic and formic acids. We also found a strong advantage in the solubilization of TCP and phosphorus (P) availability for PSB inoculation especially in the cooling stage. Redundancy analysis and structural equation models demonstrated inoculation by different methods changed the correlation of the bacterial community composition with P fractions as well as organic acids, and strengthened the cooperative function related to P transformation among species during composting. Finally, we proposed a possible mechanism of P solubilization with enriched PSB inoculation, which was induced by bacterial community and organic acids production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Role of lauric acid-potassium hydroxide concentration on bacterial contamination of spray washed broiler carcasses

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A series of experiments were conducted to examine reductions in bacterial contamination of broiler carcasses washed in a spray cabinet with various concentrations of lauric acid (LA)-potassium hydroxide (KOH) solutions. Fifty eviscerated carcasses and 5 ceca were obtained from the processing line of...

Effects of bacterial action on waste rock producing acid drainage in the Brazilian first uranium mine

International Nuclear Information System (INIS)

Rey-Silva, Daniela V.F.M.; Oliveira, Alexandre P. de; Geraldo, Bianca; Campos, Michele B.; Azevedo, Heliana de; Barreto, Rodrigo P.; Souza-Santos, Marcio L. de

2009-01-01

This work is an evolution of the methodology showed in the paper 'Study of waste of waste rock piles producing acid drainage in the Brazilian first uranium mine', also submitted for INAC2009. Therefore, the present work also related to the determination of chemical species leaching from waste rock pile 4 (WRP4) of the Uranium Mine and Milling Facility located in the Pocos de Caldas Plateau, as well as the generation of acid waters. With the previous experimental setup, it has been observed that not only water and available oxygen are significant to pyrite oxidation reaction, but bacterial activity as well. As a first approach, the present work addresses the same experiment, but now testing without the influence of bacterial action. Therefore, the new methodology and experimental setup is now capable of determining the acidity of water in contact with material from the WRP4 and the concentration of chemical species dissolved as function of time. Such would also show the extent of bacterial action interference on the pyrite oxidation reaction. Results are based on mass balances comparing concentrations of chemical species in the waste rock before the experiment and in the waste rock plus the remaining water after the experiment. In addition, the evolution of the pH and EMF (electromotive force) values along with chemical species quantified through the experiment are presented through graphics. That is followed by discussions on the significance of such results in terms of concentration of the involved chemical species. The present work has also shown the need of improving the injection of air into the system. A more sophisticated experimental setup should be assembled in the near future, which would allow the quantification of differences between experimental tests with and without bacterial action. (author)

Eubacterium rangiferina, a novel usnic acid-resistant bacterium from the reindeer rumen

Science.gov (United States)

Sundset, Monica A.; Kohn, Alexandra; Mathiesen, Svein D.; Præsteng, Kirsti E.

2008-08-01

Reindeer are able to eat and utilize lichens as an important source of energy and nutrients. In the current study, the activities of antibiotic secondary metabolites including usnic, antranoric, fumarprotocetraric, and lobaric acid commonly found in lichens were tested against a collection of 26 anaerobic rumen bacterial isolates from reindeer ( Rangifer tarandus tarandus) using the agar diffusion method. The isolates were identified based on their 16S ribosomal ribonucleic acid (rRNA) gene sequences. Usnic acid had a potent antimicrobial effect against 25 of the isolates, belonging to Clostridiales, Enterococci, and Streptococci. Isolates of Clostridia and Streptococci were also susceptible to atranoric and lobaric acid. However, one isolate (R3_91_1) was found to be resistant to usnic, antranoric, fumarprotocetraric, and lobaric acid. R3_91_1 was also seen invading and adhering to lichen particles when grown in a liquid anaerobic culture as demonstrated by transmission electron microscopy. This was a Gram-negative, nonmotile rod (0.2-0.7 × 2.0-3.5 μm) with a deoxyribonucleic acid G + C content of 47.0 mol% and main cellular fatty acids including 15:0 anteiso-dimethyl acetal (DMA), 16:0 iso-fatty acid methyl ester (FAME), 13:0 iso-3OH FAME, and 17:0 anteiso-FAME, not matching any of the presently known profiles in the MIDI database. Combined, the phenotypic and genotypic traits including the 16S rRNA gene sequence show that R3_91_1 is a novel species inside the order Clostridiales within the family Lachnospiraceae, for which we propose the name Eubacterium rangiferina. This is the first record of a rumen bacterium able to tolerate and grow in the presence of usnic acid, indicating that the rumen microorganisms in these animals have adapted mechanisms to deal with lichen secondary metabolites, well known for their antimicrobial and toxic effects.

Quantitative determination of deoxyribonucleic acid in rat brain

Science.gov (United States)

Penn, N. W.; Suwalski, R.

1969-01-01

1. A procedure is given for spectrophotometric analysis of rat brain DNA after its resolution into component bases. Amounts of tissue in the range 50–100mg. can be used. 2. The amount of DNA obtained by the present method is 80% greater than that reported for rat brain by a previous procedure specific for DNA thymine. Identity of the material is established by the base ratios of purines and pyrimidines. The features responsible for the higher yield are the presence of dioxan during alkaline hydrolysis of tissue, the determination of the optimum concentration of potassium hydroxide in this step and omission of organic washes of the initial acid-precipitated residues. 3. The requirement for dioxan during alkaline hydrolysis suggests a possible association of brain DNA with lipid. The concentration of potassium hydroxide that gives maximum yield is 0·1m, indicating that there may be internucleotide linkages in this DNA that are more sensitive to alkali than those of liver or thymus DNA. 4. This procedure gives low yields of DNA from liver. It is not suitable for analysis of the DNA from this tissue. PMID:5353529

Fluorescence quenching of graphene oxide combined with the site-specific cleavage of restriction endonuclease for deoxyribonucleic acid demethylase activity assay

Energy Technology Data Exchange (ETDEWEB)

Ji, Lijuan; Qian, Yingdan; Wu, Ping; Zhang, Hui; Cai, Chenxin, E-mail: cxcai@njnu.edu.cn

2015-04-15

Highlights: • An approach for sensitive and selective DNA demethylase activity assay is reported. • This assay is based on the fluorescence quenching of GO and site-specific cleavage of endonuclease. • It can determine as low as 0.05 ng mL{sup −1} of MBD2 with a linear range of 0.2–300 ng mL{sup −1}. • It has an ability to recognize MBD2 from other possibly coexisting proteins and cancer cell extracts. • It can avoid false signals, requiring no bisulfite conversion, PCR amplification, radioisotope-labeling. - Abstract: We report on the development of a sensitive and selective deoxyribonucleic acid (DNA) demethylase (using MBD2 as an example) activity assay by coupling the fluorescence quenching of graphene oxide (GO) with the site-specific cleavage of HpaII endonuclease to improve the selectivity. This approach was developed by designing a single-stranded probe (P1) that carries a binding region to facilitate the interaction with GO, which induces fluorescence quenching of the labeled fluorophore (FAM, 6-carboxyfluorescein), and a sensing region, which contains a hemi-methylated site of 5′-CmCGG-3′, to specifically recognize the target (T1, a 32-mer DNA from the promoter region of p53 gene) and hybridize with it to form a P1/T1 duplex. After demethylation with MBD2, the duplex can be specifically cleaved using HpaII, which releases the labeled FAM from the GO surface and results in the recovery of fluorescence. However, this cleavage is blocked by the hemi-methylation of this site. Thus, the magnitude of the recovered fluorescence signal is related to the MBD2 activity, which establishes the basis of the DNA demethylase activity assay. This assay can determine as low as ∼(0.05 ± 0.01) ng mL{sup −1} (at a signal/noise of 3) of MBD2 with a linear range of 0.2–300 ng mL{sup −1} and recognize MBD2 from other possibly coexisting proteins and cancer cell extracts. The advantage of this assay is its ability to avoid false signals and no

Antimicrobial and immune modulatory effects of lactic acid and short chain fatty acids produced by vaginal microbiota associated with eubiosis and bacterial vaginosis

Science.gov (United States)

Aldunate, Muriel; Srbinovski, Daniela; Hearps, Anna C.; Latham, Catherine F.; Ramsland, Paul A.; Gugasyan, Raffi; Cone, Richard A.; Tachedjian, Gilda

2015-01-01

Lactic acid and short chain fatty acids (SCFAs) produced by vaginal microbiota have reported antimicrobial and immune modulatory activities indicating their potential as biomarkers of disease and/or disease susceptibility. In asymptomatic women of reproductive-age the vaginal microbiota is comprised of lactic acid-producing bacteria that are primarily responsible for the production of lactic acid present at ~110 mM and acidifying the vaginal milieu to pH ~3.5. In contrast, bacterial vaginosis (BV), a dysbiosis of the vaginal microbiota, is characterized by decreased lactic acid-producing microbiota and increased diverse anaerobic bacteria accompanied by an elevated pH>4.5. BV is also characterized by a dramatic loss of lactic acid and greater concentrations of mixed SCFAs including acetate, propionate, butyrate, and succinate. Notably women with lactic acid-producing microbiota have more favorable reproductive and sexual health outcomes compared to women with BV. Regarding the latter, BV is associated with increased susceptibility to sexually transmitted infections (STIs) including HIV. In vitro studies demonstrate that lactic acid produced by vaginal microbiota has microbicidal and virucidal activities that may protect against STIs and endogenous opportunistic bacteria as well as immune modulatory properties that require further characterization with regard to their effects on the vaginal mucosa. In contrast, BV-associated SCFAs have far less antimicrobial activity with the potential to contribute to a pro-inflammatory vaginal environment. Here we review the composition of lactic acid and SCFAs in respective states of eubiosis (non-BV) or dysbiosis (BV), their effects on susceptibility to bacterial/viral STIs and whether they have inherent microbicidal/virucidal and immune modulatory properties. We also explore their potential as biomarkers for the presence and/or increased susceptibility to STIs. PMID:26082720

Antimicrobial and immune modulatory effects of lactic acid and short chain fatty acids produced by vaginal microbiota associated with eubiosis and bacterial vaginosis

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Muriel eAldunate

2015-06-01

Full Text Available Lactic acid and short chain fatty acids (SCFAs produced by vaginal microbiota have reported antimicrobial and immune modulatory activities indicating their potential as biomarkers of disease and/or disease susceptibility. In asymptomatic women of reproductive-age the vaginal microbiota is comprised of lactic acid-producing bacteria that are primarily responsible for the production of lactic acid present at ~110 mM and acidifying the vaginal milieu to pH ~3.5. In contrast, bacterial vaginosis (BV, a dysbiosis of the vaginal microbiota, is characterized by decreased lactic acid-producing microbiota and increased diverse anaerobic bacteria accompanied by an elevated pH>4.5. BV is also characterized by a dramatic loss of lactic acid and greater concentrations of mixed SCFAs including acetate, propionate, butyrate and succinate. Notably women with lactic acid-producing microbiota have more favorable reproductive and sexual health outcomes compared to women with BV. Regarding the latter, BV is associated with increased susceptibility to sexually transmitted infections (STIs including HIV. In vitro studies demonstrate that lactic acid produced by vaginal microbiota has microbicidal and virucidal activities that may protect against STIs and endogenous opportunistic bacteria as well as immune modulatory properties that require further characterization with regard to their effects on the vaginal mucosa. In contrast, BV-associated SCFAs have far less antimicrobial activity with the potential to contribute to a pro-inflammatory vaginal environment. Here we review the composition of lactic acid and SCFAs in respective states of eubiosis (non-BV or dysbiosis (BV, their effects on susceptibility to bacterial/viral STIs and whether they have inherent microbicidal/virucidal and immune modulatory properties. We also explore their potential as biomarkers for the presence and/or increased susceptibility to STIs.

Antimicrobial and immune modulatory effects of lactic acid and short chain fatty acids produced by vaginal microbiota associated with eubiosis and bacterial vaginosis.

Science.gov (United States)

Aldunate, Muriel; Srbinovski, Daniela; Hearps, Anna C; Latham, Catherine F; Ramsland, Paul A; Gugasyan, Raffi; Cone, Richard A; Tachedjian, Gilda

2015-01-01

Lactic acid and short chain fatty acids (SCFAs) produced by vaginal microbiota have reported antimicrobial and immune modulatory activities indicating their potential as biomarkers of disease and/or disease susceptibility. In asymptomatic women of reproductive-age the vaginal microbiota is comprised of lactic acid-producing bacteria that are primarily responsible for the production of lactic acid present at ~110 mM and acidifying the vaginal milieu to pH ~3.5. In contrast, bacterial vaginosis (BV), a dysbiosis of the vaginal microbiota, is characterized by decreased lactic acid-producing microbiota and increased diverse anaerobic bacteria accompanied by an elevated pH>4.5. BV is also characterized by a dramatic loss of lactic acid and greater concentrations of mixed SCFAs including acetate, propionate, butyrate, and succinate. Notably women with lactic acid-producing microbiota have more favorable reproductive and sexual health outcomes compared to women with BV. Regarding the latter, BV is associated with increased susceptibility to sexually transmitted infections (STIs) including HIV. In vitro studies demonstrate that lactic acid produced by vaginal microbiota has microbicidal and virucidal activities that may protect against STIs and endogenous opportunistic bacteria as well as immune modulatory properties that require further characterization with regard to their effects on the vaginal mucosa. In contrast, BV-associated SCFAs have far less antimicrobial activity with the potential to contribute to a pro-inflammatory vaginal environment. Here we review the composition of lactic acid and SCFAs in respective states of eubiosis (non-BV) or dysbiosis (BV), their effects on susceptibility to bacterial/viral STIs and whether they have inherent microbicidal/virucidal and immune modulatory properties. We also explore their potential as biomarkers for the presence and/or increased susceptibility to STIs.

Bacterial fatty acids enhance recovery from the dauer larva in Caenorhabditis elegans.

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Tiffany K Kaul

Full Text Available The dauer larva is a specialized dispersal stage in the nematode Caenorhabditis elegans that allows the animal to survive starvation for an extended period of time. The dauer does not feed, but uses chemosensation to identify new food sources and to determine whether to resume reproductive growth. Bacteria produce food signals that promote recovery of the dauer larva, but the chemical identities of these signals remain poorly defined. We find that bacterial fatty acids in the environment augment recovery from the dauer stage under permissive conditions. The effect of increased fatty acids on different dauer constitutive mutants indicates a role for insulin peptide secretion in coordinating recovery from the dauer stage in response to fatty acids. These data suggest that worms can sense the presence of fatty acids in the environment and that elevated levels can promote recovery from dauer arrest. This may be important in the natural environment where the dauer larva needs to determine whether the environment is appropriate to support reproductive growth following dauer exit.

Evaluation of different lactic acid bacterial strains for probiotic characteristics

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B. Srinu,

2013-08-01

Full Text Available Objective: The objective of the present study was to collect different Lactic acid bacterial strains from culture collection centers and screen their functional probiotic characteristics such as acid tolerance, bile tolerance, antibacterial activity and antibiotic sensitivity for their commercial use. Materials and Methods: Acid and bile tolerence of selected LAB(Lactic acid bacteria was determined. The antibiotic resistance of Lactobacillus species was assessed using different antibiotic discs on de Mann Rogosa Sharpe broth (MRS agar plates seeded with the test probiotic organism. The antibacterial activity of LAB was assessed by using well diffusion method.Results: Among the six probiotic strains tested, all showed good survivability at high bile salt concentration (0.3 to 2.0 % oxgall and good growth at a low pH of 1.5 to 3.5. These probiotic species showed good survival abilities in acidic pH of 2.0 to 3.5 except Lactobacillus delbrueckii subspp. bulgaricus 281 which did not grown at pH of 2.0. Lactobacillus fermentum 141 was able to grow even at pH of 1.5 also. Among the six lactic acid species, Lactobacillus fermentum 141 (except Tetracycline, Lactobacillus delbrueckii subspp. Bulgaricus 281 except (Cefpodoxime and all other LAB were resistant to all the antibiotics tested (Ampicillin, Nalidixic acid , Ciprofloxacin ,Co-Trimoxazole, Gentamicin and Cefpodoxime. All these probiotic organisms were screened for their in vitro inhibition ability against pathogenic microorganisms namely, E.coli ATCC (American type culture collection centre, Pseudomonas aeruginosa, Salmonella paratyphi, Staphylococcus aureus. Lactobacillus delbrueckii subspp. bulgaricus 281, Lactobacillus casei 297 and Lactobacillus fermentum 141 inhibited the growth of all the pathogenic bacteria used in the study. Conclusion: The study indicated Lactobacillus fermentum 141 and Lactobacillus casei 297 as potential functional probiotics for future in vivo studies for

Algal and bacterial activities in acidic (pH 3) strip mine lakes

International Nuclear Information System (INIS)

Gyure, R.A.; Konopka, A.; Brooks, A.; Doemel, W.

1987-01-01

Reservoir 29 and Lake B are extremely acid lakes (epilimnion pHs of 2.7 and 3.2, respectively), because they receive acidic discharges from coal refuse piles. They differ in that the pH of profundal sediments in Reservoir 29 increased from 2.7 to 3.8 during the period of thermal stratification, whereas permanently anoxic sediments in Lake B had a pH of 6.2. The pH rise in Reservoir 29 sediments was correlated with a temporal increase in H 2 S concentration in the anaerobic hypolimnion from 0 to >1 mM. The chlorophyll a levels in the epilimnion of Reservoir 29 were low, and the rate of primary production was typical of an oligotrophic system. However, there was a dense 10-cm layer of algal biomass at the bottom of the metalimnion. Production by this layer was low owing to light limitation and possibly H 2 S toxicity. The specific photosynthetic rates of epilimnetic algae were low, which suggests that nutrient availability is more important than pH in limiting production. The highest photosynthetic rates were obtained in water samples incubated at pH 2.7 to 4. Heterotrophic bacterial activity (measured by [ 14 C]glucose metabolism) was greatest at the sediment/water interface. Bacterial production (assayed by thymidine incorporation) was as high in Reservoir 29 as in a nonacid mesotrophic Indiana lake

Acidic Conditions in the NHE2-/- Mouse Intestine Result in an Altered Mucosa-Associated Bacterial Population with Changes in Mucus Oligosaccharides

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Melinda A. Engevik

2013-12-01

Full Text Available Background: The mechanisms bacteria use to proliferate and alter the normal bacterial composition remain unknown. The ability to link changes in the intestinal micro-environment, such as ion composition and pH, to bacterial proliferation is clinically advantageous for diseases that involve an altered gut microbiota, such as Inflammatory Bowel Disease, obesity and diabetes. In human and mouse intestine, the apical Na+/H+ exchangers NHE2 and NHE3 affect luminal Na+, water, and pH. Loss of NHE2 results in acidic luminal pH. Since acid resistance systems in gram-positive bacteria are well documented, we hypothesize that gram-positive bacteria would increase in representation in the acidic NHE2-/- intestine. Methods: Intestinal ion composition was measured by fame photometry and chloridometry and pH measured electrochemically. DNA extracted from intestinal flushes or from mucosal scrapings was analyzed by qRT-PCR to examine luminal and mucosa-associated bacterial populations. Epithelial mucus oligosaccharide patterns were examined by histology with FIT-C labeled lectins. Results: Although total luminal and mucosa-associated bacteria were unchanged in NHE2-/- intestine, gram-positive bacterial phyla were increased in the mucosa-associated bacterial population in a region-specific manner. The genera Clostridium and Lactobacillus were increased in the cecum and colon which corresponded to changes in NHE2-/- mucus oligosaccharide composition of mannose, N-acetyglucosamine, N-acetygalactosamine and galactose. Conclusions: Together these data indicate that changes in ion transport induce region-specific bacterial changes, which alter host mucus oligosaccharide patterns. These host-bacterial interactions provide a possible mechanism of niche-development and shed insight on how certain groups proliferate in changing environments and maintain their proliferation by altering the host.

Bacterial, Archaeal, and Eukaryotic Diversity across Distinct Microhabitats in an Acid Mine Drainage

Science.gov (United States)

Mesa, Victoria; Gallego, Jose L. R.; González-Gil, Ricardo; Lauga, Béatrice; Sánchez, Jesús; Méndez-García, Celia; Peláez, Ana I.

2017-01-01

Acid mine drainages are characterized by their low pH and the presence of dissolved toxic metallic species. Microorganisms survive in different microhabitats within the ecosystem, namely water, sediments, and biofilms. In this report, we surveyed the microbial diversity within all domains of life in the different microhabitats at Los Rueldos abandoned mercury underground mine (NW Spain), and predicted bacterial function based on community composition. Sediment samples contained higher proportions of soil bacteria (AD3, Acidobacteria), as well as Crenarchaeota and Methanomassiliicoccaceae archaea. Oxic and hypoxic biofilm samples were enriched in bacterial iron oxidizers from the genus Leptospirillum, order Acidithiobacillales, class Betaproteobacteria, and archaea from the class Thermoplasmata. Water samples were enriched in Cyanobacteria and Thermoplasmata archaea at a 3–98% of the sunlight influence, whilst Betaproteobacteria, Thermoplasmata archaea, and Micrarchaea dominated in acid water collected in total darkness. Stalactites hanging from the Fe-rich mine ceiling were dominated by the neutrophilic iron oxidizer Gallionella and other lineages that were absent in the rest of the microhabitats (e.g., Chlorobi, Chloroflexi). Eukaryotes were detected in biofilms and open-air water samples, and belonged mainly to clades SAR (Alveolata and Stramenopiles), and Opisthokonta (Fungi). Oxic and hypoxic biofilms displayed higher proportions of ciliates (Gonostomum, Oxytricha), whereas water samples were enriched in fungi (Paramicrosporidium and unknown microbial Helotiales). Predicted function through bacterial community composition suggested adaptive evolutive convergence of function in heterogeneous communities. Our study showcases a broad description of the microbial diversity across different microhabitats in the same environment and expands the knowledge on the diversity of microbial eukaryotes in AMD habitats. PMID:28955322

Bacterial, Archaeal, and Eukaryotic Diversity across Distinct Microhabitats in an Acid Mine Drainage

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Victoria Mesa

2017-09-01

Full Text Available Acid mine drainages are characterized by their low pH and the presence of dissolved toxic metallic species. Microorganisms survive in different microhabitats within the ecosystem, namely water, sediments, and biofilms. In this report, we surveyed the microbial diversity within all domains of life in the different microhabitats at Los Rueldos abandoned mercury underground mine (NW Spain, and predicted bacterial function based on community composition. Sediment samples contained higher proportions of soil bacteria (AD3, Acidobacteria, as well as Crenarchaeota and Methanomassiliicoccaceae archaea. Oxic and hypoxic biofilm samples were enriched in bacterial iron oxidizers from the genus Leptospirillum, order Acidithiobacillales, class Betaproteobacteria, and archaea from the class Thermoplasmata. Water samples were enriched in Cyanobacteria and Thermoplasmata archaea at a 3–98% of the sunlight influence, whilst Betaproteobacteria, Thermoplasmata archaea, and Micrarchaea dominated in acid water collected in total darkness. Stalactites hanging from the Fe-rich mine ceiling were dominated by the neutrophilic iron oxidizer Gallionella and other lineages that were absent in the rest of the microhabitats (e.g., Chlorobi, Chloroflexi. Eukaryotes were detected in biofilms and open-air water samples, and belonged mainly to clades SAR (Alveolata and Stramenopiles, and Opisthokonta (Fungi. Oxic and hypoxic biofilms displayed higher proportions of ciliates (Gonostomum, Oxytricha, whereas water samples were enriched in fungi (Paramicrosporidium and unknown microbial Helotiales. Predicted function through bacterial community composition suggested adaptive evolutive convergence of function in heterogeneous communities. Our study showcases a broad description of the microbial diversity across different microhabitats in the same environment and expands the knowledge on the diversity of microbial eukaryotes in AMD habitats.

Mitigation of membrane biofouling by d-amino acids: Effect of bacterial cell-wall property and d-amino acid type.

Science.gov (United States)

Wang, Si-Yu; Sun, Xue-Fei; Gao, Wen-Jing; Wang, Yi-Fu; Jiang, Bei-Bei; Afzal, Muhammad Zaheer; Song, Chao; Wang, Shu-Guang

2018-04-01

Development of novel approaches for biofouling mitigation is of crucial importance for membrane-based technologies. d-amino acids (d-AAs) have been proposed as a potential strategy to mitigate biofouling. However, the effect of bacterial cell-wall properties and d-AAs type on biofouling mitigation remains unclear. This study assesses the effect of d-AAs type on membrane biofouling control, towards Gram positive (G+) and Gram negative (G-) bacteria. Three kinds of d-AAs were found to inhibit both G+ and G- bacterial attachment in short-term attachment and dead-end filtration experiments. The existence of d-AAs reduces extracellular polysaccharides and proteins on the membrane, which may decrease membrane biofouling. Cross-flow filtration tests further indicated that d-AAs could effectively reduce membrane biofouling. The permeate flux recovery post chemical cleaning, improved for both P. aeruginosa and B. subtilis treated with d-AAs. The results obtained from this study enable better understanding of the role of d-AAs species on bacterial adhesion and biofilm formation. This may provide a new way to regulate biofilm formation by manipulating the species of d-AAs membrane systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Experimental Warming Decreases the Average Size and Nucleic Acid Content of Marine Bacterial Communities

KAUST Repository

Huete-Stauffer, Tamara M.

2016-05-23

Organism size reduction with increasing temperature has been suggested as a universal response to global warming. Since genome size is usually correlated to cell size, reduction of genome size in unicells could be a parallel outcome of warming at ecological and evolutionary time scales. In this study, the short-term response of cell size and nucleic acid content of coastal marine prokaryotic communities to temperature was studied over a full annual cycle at a NE Atlantic temperate site. We used flow cytometry and experimental warming incubations, spanning a 6°C range, to analyze the hypothesized reduction with temperature in the size of the widespread flow cytometric bacterial groups of high and low nucleic acid content (HNA and LNA bacteria, respectively). Our results showed decreases in size in response to experimental warming, which were more marked in 0.8 μm pre-filtered treatment rather than in the whole community treatment, thus excluding the role of protistan grazers in our findings. Interestingly, a significant effect of temperature on reducing the average nucleic acid content (NAC) of prokaryotic cells in the communities was also observed. Cell size and nucleic acid decrease with temperature were correlated, showing a common mean decrease of 0.4% per °C. The usually larger HNA bacteria consistently showed a greater reduction in cell and NAC compared with their LNA counterparts, especially during the spring phytoplankton bloom period associated to maximum bacterial growth rates in response to nutrient availability. Our results show that the already smallest planktonic microbes, yet with key roles in global biogeochemical cycling, are likely undergoing important structural shrinkage in response to rising temperatures.

Experimental Warming Decreases the Average Size and Nucleic Acid Content of Marine Bacterial Communities

KAUST Repository

Huete-Stauffer, Tamara M.; Arandia-Gorostidi, Nestor; Alonso-Sá ez, Laura; Moran, Xose Anxelu G.

2016-01-01

Organism size reduction with increasing temperature has been suggested as a universal response to global warming. Since genome size is usually correlated to cell size, reduction of genome size in unicells could be a parallel outcome of warming at ecological and evolutionary time scales. In this study, the short-term response of cell size and nucleic acid content of coastal marine prokaryotic communities to temperature was studied over a full annual cycle at a NE Atlantic temperate site. We used flow cytometry and experimental warming incubations, spanning a 6°C range, to analyze the hypothesized reduction with temperature in the size of the widespread flow cytometric bacterial groups of high and low nucleic acid content (HNA and LNA bacteria, respectively). Our results showed decreases in size in response to experimental warming, which were more marked in 0.8 μm pre-filtered treatment rather than in the whole community treatment, thus excluding the role of protistan grazers in our findings. Interestingly, a significant effect of temperature on reducing the average nucleic acid content (NAC) of prokaryotic cells in the communities was also observed. Cell size and nucleic acid decrease with temperature were correlated, showing a common mean decrease of 0.4% per °C. The usually larger HNA bacteria consistently showed a greater reduction in cell and NAC compared with their LNA counterparts, especially during the spring phytoplankton bloom period associated to maximum bacterial growth rates in response to nutrient availability. Our results show that the already smallest planktonic microbes, yet with key roles in global biogeochemical cycling, are likely undergoing important structural shrinkage in response to rising temperatures.

Glyphosate has limited short-term effects on commensal bacterial community composition in the gut environment due to sufficient aromatic amino acid levels

DEFF Research Database (Denmark)

Nielsen, Lene Nørby; Roager, Henrik Munch; Casas, Mònica Escolà

2017-01-01

in acetic acid produced by the gut bacteria. We conclude that sufficient intestinal levels of aromatic amino acids provided by the diet alleviates the need for bacterial synthesis of aromatic amino acids and thus prevents an antimicrobial effect of glyphosate in vivo. It is however possible...

A new approach in the first-line treatment of bacterial and mycotic vulvovaginitis with topical lipohydroperoxides and glycyrrhetic acid: a comparative study.

Science.gov (United States)

Mainini, G; Rotondi, M; Scaffa, C

2011-01-01

PURPOSE OF INVESTIGATIONS: The aim of this randomized controlled trial was to evaluate efficacy and tolerability of a new association of lipohydroperoxides and glycyrrhetic acid on topical treatment of bacterial and mycotic vulvovaginitis. One hundred consecutive patients with bacterial or mycotic vulvovaginitis were randomly assigned to a study group treated with vaginal lipohydroperoxides and a derivative of glycyrrhetic acid for three days (n = 50), and a control group using vaginal antibacterial metronidazole (500 mg) or antimycotic econazole (150 mg) for six days (n = 50). A clinical and microbiological response was achieved in 80.4% and 88.9% in investigational and control group, respectively (p > 0.05). Compared to traditional antimicrobial drugs, the effect appears to be faster and safer, even if not significantly. The 6-month recurrence rate was 7.7% and 5.6% in the investigational and control group, respectively. Topical medication based on lipohydroperoxides and glycyrrhetic acid showed a clinical and microbiological efficacy in the first-line treatment of bacterial and mycotic vulvovaginitis, comparable to conventional drugs.

Binding mechanisms for histamine and agmatine ligands in plasmid deoxyribonucleic acid purifications.

Science.gov (United States)

Sousa, Ângela; Pereira, Patrícia; Sousa, Fani; Queiroz, João A

2014-10-31

Histamine and agmatine amino acid derivatives were immobilized into monolithic disks, in order to combine the specificity and selectivity of the ligand with the high mass transfer and binding capacity offered by monolithic supports, to purify potential plasmid DNA biopharmaceuticals. Different elution strategies were explored by changing the type and salt concentration, as well as the pH, in order to understand the retention pattern of different plasmids isoforms The pVAX1-LacZ supercoiled isoform was isolated from a mixture of pDNA isoforms by using NaCl increasing stepwise gradient and also by ammonium sulfate decreasing stepwise gradient, in both histamine and agmatine monoliths. Acidic pH in the binding buffer mainly strengthened ionic interactions with both ligands in the presence of sodium chloride. Otherwise, for histamine ligand, pH values higher than 7 intensified hydrophobic interactions in the presence of ammonium sulfate. In addition, circular dichroism spectroscopy studies revealed that the binding and elution chromatographic conditions, such as the combination of high ionic strength with extreme pH values can reversibly influence the structural stability of the target nucleic acid. Therefore, ascending sodium chloride gradients with pH manipulation can be preferable chromatographic conditions to be explored in the purification of plasmid DNA biopharmaceuticals, in order to avoid the environmental impact of ammonium sulfate. Copyright © 2014. Published by Elsevier B.V.

Acidic pH sensing in the bacterial cytoplasm is required for Salmonella virulence.

Science.gov (United States)

Choi, Jeongjoon; Groisman, Eduardo A

2016-09-01

pH regulates gene expression, biochemical activities and cellular behaviors. A mildly acidic pH activates the master virulence regulatory system PhoP/PhoQ in the facultative intracellular pathogen Salmonella enterica serovar Typhimurium. The sensor PhoQ harbors an extracytoplasmic domain implicated in signal sensing, and a cytoplasmic domain controlling activation of the regulator PhoP. We now report that, surprisingly, a decrease in Salmonella's own cytoplasmic pH induces transcription of PhoP-activated genes even when the extracytoplasmic pH remains neutral. Amino acid substitutions in PhoQ's cytoplasmic domain hindered activation by acidic pH and attenuated virulence in mice, but did not abolish activation by low Mg(2+) or the antimicrobial peptide C18G. Conversely, removal of PhoQ's extracytoplasmic domains prevented the response to the latter PhoQ-activating signals but not to acidic pH. PhoP-dependent genes were minimally induced by acidic pH in the non-pathogenic species Salmonella bongori but were activated by low Mg(2+) and C18G as in pathogenic S. enterica. Our findings indicate that the sensor PhoQ enables S. enterica to respond to both host- and bacterial-derived signals that alter its cytoplasmic pH. © 2016 John Wiley & Sons Ltd.

Crystal structure of a bacterial homologue of the bile acid sodium symporter ASBT

Science.gov (United States)

Hu, Nien-Jen; Iwata, So; Cameron, Alexander D.; Drew, David

2011-01-01

High cholesterol levels greatly increase the risk of cardiovascular disease. By its conversion into bile acids, about 50% of cholesterol is eliminated from the body. However bile acids released from the bile duct are constantly recycled, being reabsorbed in the intestine via the Apical Sodium dependent Bile acid Transporter (ASBT). It has been shown in animal models that plasma cholesterol levels are significantly lowered by specific inhibitors of ASBT1,2, thus ASBT is a target for hypercholesterolemia drugs. Here, we describe the crystal structure of a bacterial homologue of ASBT from Neisseria meningitidis (ASBTNM) at 2.2Å. ASBTNM contains two inverted structural repeats of five transmembrane helices. A Core domain of six helices harbours two sodium ions while the remaining helices form a Panel-like domain. Overall the architecture of the protein is remarkably similar to the sodium-proton antiporter NhaA3 despite no detectable sequence homology. A bile acid molecule is situated between the Core and Panel domains in a large hydrophobic cavity. Residues near to this cavity have been shown to affect the binding of specific inhibitors of human ASBT4. The position of the bile acid together with the molecular architecture suggests the rudiments of a possible transport mechanism. PMID:21976025

The bile acid deoxycholate elicits defences in Arabidopsis and reduces bacterial infection.

Science.gov (United States)

Zarattini, Marco; Launay, Alban; Farjad, Mahsa; Wénès, Estelle; Taconnat, Ludivine; Boutet, Stéphanie; Bernacchia, Giovanni; Fagard, Mathilde

2017-05-01

Disease has an effect on crop yields, causing significant losses. As the worldwide demand for agricultural products increases, there is a need to pursue the development of new methods to protect crops from disease. One mechanism of plant protection is through the activation of the plant immune system. By exogenous application, 'plant activator molecules' with elicitor properties can be used to activate the plant immune system. These defence-inducing molecules represent a powerful and often environmentally friendly tool to fight pathogens. We show that the secondary bile acid deoxycholic acid (DCA) induces defence in Arabidopsis and reduces the proliferation of two bacterial phytopathogens: Erwinia amylovora and Pseudomonas syringae pv. tomato. We describe the global defence response triggered by this new plant activator in Arabidopsis at the transcriptional level. Several induced genes were selected for further analysis by quantitative reverse transcription-polymerase chain reaction. We describe the kinetics of their induction and show that abiotic stress, such as moderate drought or nitrogen limitation, does not impede DCA induction of defence. Finally, we investigate the role in the activation of defence by this bile acid of the salicylic acid biosynthesis gene SID2, of the receptor-like kinase family genes WAK1-3 and of the NADPH oxidase-encoding RbohD gene. Altogether, we show that DCA constitutes a promising molecule for plant protection which can induce complementary lines of defence, such as callose deposition, reactive oxygen species accumulation and the jasmonic acid and salicylic acid signalling pathways. © 2016 BSPP AND JOHN WILEY & SONS LTD.

Pediatric tuberculosis-human immunodeficiency virus co-infection in the United Kingdom highlights the need for better therapy monitoring tools: a case report.

Science.gov (United States)

Evangelopoulos, Dimitrios; Whittaker, Elizabeth; Honeyborne, Isobella; McHugh, Timothy D; Klein, Nigel; Shingadia, Delane

2017-02-26

Tuberculosis is an infection that requires at least 6 months of chemotherapy in order to clear the bacteria from the patient's lungs. Usually, therapeutic monitoring is dependent on smear microscopy where a decline in acid-fast bacilli is observed. However, this might not be indicative of the actual decline of bacterial load and thus other tools such as culture and molecular assays are required for patient management. Here, we report the case of a 12-year-old Black African boy co-infected with tuberculosis and human immunodeficiency virus who remained smear culture positive and liquid culture negative for a prolonged period of time following chemotherapy. In order to determine whether there was any live bacteria present in his specimens, we applied the newly developed molecular bacterial load assay that detects the presence of 16S ribosomal ribonucleic acid derived from the bacteria. Using this methodology, we were able to quantify his bacterial load and inform the management of his treatment in order to reduce the disease burden. Following this intervention he went on to make a complete recovery. This case report highlights the value of improved biomarkers for monitoring the treatment of tuberculosis and the role of molecular assays such as the molecular bacterial load assay applied here. The molecular bacterial load assay detects bacterial ribonucleic acid which corresponds closely with the number of live bacilli as compared with polymerase chain reaction that detects deoxyribonucleic acid and may include dead bacteria.

Host-Derived Sialic Acids Are an Important Nutrient Source Required for Optimal Bacterial Fitness In Vivo

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Nathan D. McDonald

2016-04-01

Full Text Available A major challenge facing bacterial intestinal pathogens is competition for nutrient sources with the host microbiota. Vibrio cholerae is an intestinal pathogen that causes cholera, which affects millions each year; however, our knowledge of its nutritional requirements in the intestinal milieu is limited. In this study, we demonstrated that V. cholerae can grow efficiently on intestinal mucus and its component sialic acids and that a tripartite ATP-independent periplasmic SiaPQM strain, transporter-deficient mutant NC1777, was attenuated for colonization using a streptomycin-pretreated adult mouse model. In in vivo competition assays, NC1777 was significantly outcompeted for up to 3 days postinfection. NC1777 was also significantly outcompeted in in vitro competition assays in M9 minimal medium supplemented with intestinal mucus, indicating that sialic acid uptake is essential for fitness. Phylogenetic analyses demonstrated that the ability to utilize sialic acid was distributed among 452 bacterial species from eight phyla. The majority of species belonged to four phyla, Actinobacteria (members of Actinobacillus, Corynebacterium, Mycoplasma, and Streptomyces, Bacteroidetes (mainly Bacteroides, Capnocytophaga, and Prevotella, Firmicutes (members of Streptococcus, Staphylococcus, Clostridium, and Lactobacillus, and Proteobacteria (including Escherichia, Shigella, Salmonella, Citrobacter, Haemophilus, Klebsiella, Pasteurella, Photobacterium, Vibrio, and Yersinia species, mostly commensals and/or pathogens. Overall, our data demonstrate that the ability to take up host-derived sugars and sialic acid specifically allows V. cholerae a competitive advantage in intestinal colonization and that this is a trait that is sporadic in its occurrence and phylogenetic distribution and ancestral in some genera but horizontally acquired in others.

Different reparability of the chromosomal and cytoplasmic deoxyribonucleic acid in Escherichia coli damaged by γ and ultraviolet irradiation

International Nuclear Information System (INIS)

Petranovic, D.; Petranovic, M.; Nozinic, R.; Trgovcevic, Z.

1978-01-01

The relative efficiencies by which chromosomal and extrachromosomal DNAs are repaired in irradiated bacteria were assayed. Repair-proficient Escherichia coli C600 cells lysogenic for, or infected with, the thermoinducible phage lambdacI857 ind were exposed to γ or uv radiation and then tested for colony- and plaque-forming ability. The results show that the bacterial cell is about 5 times more sensitive to γ rays and about 1.5 times more sensitive to uv light, if compared to either (1) the prophage that is irradiated in the bacterial chromosome and, on heat induction, repaired in the cytoplasm or (2) the infecting phage that is irradiated and repaired in the cytoplasm. Since the bacterial DNA is about 80 times larger than the phage DNA, it is inferred that repair processes operating along the chromosomal DNA are one order of magnitude more efficient than those operating along the extrachromosomal DNA. This conclusion is reinforced by the fact that the absence of repair in the system Escherichia coli AB2480 uvrA recA-lambdacI857 ind red gives the expected ratio of 80/1 for the uv sensitivity of cells and that of intracellular phage

Incorporation of 15N and 14C into amino acids of bacterial and protozoal protein in the rumen of the cow on urea-rich feed

Directory of Open Access Journals (Sweden)

Eeva-Liisa Syväoja

1979-01-01

Full Text Available The utilization of the non-protein nitrogen and carbon of feed by rumen microorganisms for the synthesis of protein was studied by administering [U-14C] sucrose and 15NH4Cl to a cow on urea-rich, low-protein feed. By studying the labelling of the protozoa and bacteria and the amino acids isolated from them at intervals up to 48 hours afterwards, it was found that the bacteria synthesized amino acids from nonprotein nitrogen much more rapidly and effectively than the protozoa. Also the labelling of the carbon in the amino acids of the bacteria was more rapid than in the protozoa. In both protozoa and bacteria there was intracellular storage of [14C] sucrose. Of the bacterial amino acids the most vigorous 14C labelling was found in Glu, Arg, Lys, Val and Ala and the weakest labelling in Gly, His and Ser. Of the protozoal amino acids Ala, Asp, Glu, Leu and Lys had the highest labelling and Pro, Gly, His and Phe the lowest. In the bacterial protein the labelling of Pro and Arg was ten times that of the corresponding protozoal amino acids, and Asp, Ser and Ala four times. After the 15NH4Cl dose the half-life of 15N in the rumen fluid was estimated to be 3.3 h. Labelled ammonium nitrogen was about 11 —15 % of the bacterial nitrogen and 2—3 % of the protozoal nitrogen after 1 h. Of the protozoal amino acids Ala, Glu, Val, Asp and Met had the most vigorous labelling, and of the bacterial amino acids Glu, Asp, Ser, He and Tyr. The slowest incorporation of ammonium nitrogen was into His, Pro, Arg and Gly in both bacteria and protozoa. The labelling of the bacterial amino acids was approximately 7—8 times more vigorous than that of the protozoal amino acids. The labelling of Ala was only 4 times, and that of Val, Met and Glu 5 times more vigorous than with protozoal protein. The pathway of histidine synthesis seemed to be restricted in both bacteria and protozoa and therefore may be a limiting factor in protein synthesis, particularly in cows fed

Ultra-Sensitive Biological Detection via Nanoparticle-Based Magnetically Amplified Surface Plasmon Resonance (Mag-SPR) Techniques

Science.gov (United States)

2008-10-08

surfactant such as hexadecyltrimethyl ammonium bromide (CTMA). And also CTMA- polymethacrylic acid (PMA), CTMA-Polyglutamic acid were synthesized as reference...rich world of naturally occurring biomaterials probably none is more important and more fundamental than DNA (deoxyribonucleic acid ), the polymeric...deoxyribonucleic acid gate dielectric," Journal of Applied Physics, vol. 100, p. 024514, 2006. [3] C. H. Lee, E.-D. Do, Y.-W. Kwon, D.-H. Choi, J.-I. Jin

Bacterial lipases

NARCIS (Netherlands)

Jaeger, Karl-Erich; Ransac, Stéphane; Dijkstra, Bauke W.; Colson, Charles; Heuvel, Margreet van; Misset, Onno

Many different bacterial species produce lipases which hydrolyze esters of glycerol with preferably long-chain fatty acids. They act at the interface generated by a hydrophobic lipid substrate in a hydrophilic aqueous medium. A characteristic property of lipases is called interfacial activation,

Helicase-dependent amplification of nucleic acids.

Science.gov (United States)

Cao, Yun; Kim, Hyun-Jin; Li, Ying; Kong, Huimin; Lemieux, Bertrand

2013-10-11

Helicase-dependent amplification (HDA) is a novel method for the isothermal in vitro amplification of nucleic acids. The HDA reaction selectively amplifies a target sequence by extension of two oligonucleotide primers. Unlike the polymerase chain reaction (PCR), HDA uses a helicase enzyme to separate the deoxyribonucleic acid (DNA) strands, rather than heat denaturation. This allows DNA amplification without the need for thermal cycling. The helicase used in HDA is a helicase super family II protein obtained from a thermophilic organism, Thermoanaerobacter tengcongensis (TteUvrD). This thermostable helicase is capable of unwinding blunt-end nucleic acid substrates at elevated temperatures (60° to 65°C). The HDA reaction can also be coupled with reverse transcription for ribonucleic acid (RNA) amplification. The products of this reaction can be detected during the reaction using fluorescent probes when incubations are conducted in a fluorimeter. Alternatively, products can be detected after amplification using a disposable amplicon containment device that contains an embedded lateral flow strip. Copyright © 2013 John Wiley & Sons, Inc.

Bilateral lesions of suprachiasmatic nuclei affect circadian rhythms in [3H]-thymidine incorporation into deoxyribonucleic acid in mouse intestinal tract, mitotic index of corneal epithelium, and serum corticosterone

International Nuclear Information System (INIS)

Scheving, L.E.; Tsai, T.H.; Powell, E.W.; Pasley, J.N.; Halberg, F.; Dunn, J.

1983-01-01

Investigations into the role of the suprachiasmatic nuclei (SCN) in the coordination of circadian rhythms have presented differing results. Several reports have shown that ablation of the suprachiasmatic nuclei (SCNA) alters the phase and amplitude of rhythms but does not abolish them. The present study investigates the effect of SCNA on the rhythms in cell proliferation in various regions of the intestinal tract as measured by the incorporation of [ 3 H]-thymidine into deoxyribonucleic acid, in the mitotic activity of the corneal epithelium, and in serum corticosterone levels. The study involved mice with verified lesions of the SCN (six to 13 mice per time point) and control groups of both sham-operated and unoperated mice (seven of each per time point). The mice were killed in groups that represented seven time points over a single 24 hr span (3 hr intervals with the 0800 hr sampled both at start and end of the series). The tissues examined were the tongue, esophagus, gastric stomach, and colon for DNA synthesis, the corneal epithelium for mitotic index, and blood serum for corticosterone level. The most consistent result of SCNA was a phase advance in the rhythms in cell proliferation in the tongue, esophagus, gastric stomach, colon, and corneal epithelium. A reduction in rhythm amplitude occurred in the tongue, esophagus, and corneal epithelium; however, there was an amplitude increase for the stomach, colon, and serum corticosterone. The mesor (rhythm-adjusted mean) was increased by SCNA in all tissues except the corneal epithelium. These findings further support the role of the suprachiasmatic nuclear area in the control of rhythms in cell proliferation and corticosterone production, by acting as a ''phase-resetter'' and as a modulator of rhythm amplitude

Conventional and nonconventional strategies for controlling bacterial contamination in fuel ethanol fermentations.

Science.gov (United States)

Ceccato-Antonini, Sandra Regina

2018-05-25

Ethanol bio-production in Brazil has some unique characteristics that inevitably lead to bacterial contamination, which results in the production of organic acids and biofilms and flocculation that impair the fermentation yield by affecting yeast viability and diverting sugars to metabolites other than ethanol. The ethanol-producing units commonly give an acid treatment to the cells after each fermentative cycle to decrease the bacterial number, which is not always effective. An alternative strategy must be employed to avoid bacterial multiplication but must be compatible with economic, health and environmental aspects. This review analyzes the issue of bacterial contamination in sugarcane-based fuel ethanol fermentation, and the potential strategies that may be utilized to control bacterial growth besides acid treatment and antibiotics. We have emphasized the efficiency and suitability of chemical products other than acids and those derived from natural sources in industrial conditions. In addition, we have also presented bacteriocins, bacteriophages, and beneficial bacteria as non-conventional antimicrobial agents to mitigate bacterial contamination in the bioethanol industry.

Changes in the protein fraction of Merluccius bilinearis muscle under lactic acid bacterial fermentation using a Lactobacillus Acidophilus starter culture (ESP)

OpenAIRE

Elizondo, Luis J.

2016-01-01

The effect of lactic acid bacterial fermentation on the protein fraction of Merluccius bilinearis muscle was evaluated. The non-protein fraction increased progressively with corresponding decreases in the percentage protein (dry weight) indicating proteolytic activity during fermentation. Significant increases in the percentages of the amino acids cystine, isoleucine, phenylalanine and tyrosine were observed after two months of fermentation. Percentages of arginine decreased significantly aft...

Bacterial leaching of uranium ores - a review

International Nuclear Information System (INIS)

Lowson, R.T.

1975-11-01

The bacterial leaching of uranium ores involves the bacterially catalysed oxidation of associated pyrite to sulphuric acid and Fe 3+ by autotrophic bacteria and the leaching of the uranium by the resulting acidic, oxidising solution. Industrial application has been limited to Thiobacillus thiooxidans and Thiobacillus ferrooxidans at pH 2 to 3, and examples of these are described. The bacterial catalysis can be improved with nutrients or prevented with poisons. The kinetics of leaching are controlled by the bed depth, particle size, percolation rate, mineralogy and temperature. Current work is aimed at quantitatively defining the parameters controlling the kinetics and extending the method to alkaline conditions with other autotrophic bacteria. (author)

Homology among tet determinants in conjugative elements of streptococci

Energy Technology Data Exchange (ETDEWEB)

Smith, M.D.; Hazum, S.; Guild, W.R.

1981-10-01

A mutation to tetracycline sensitivity in a resistant strain of Streptococcus pneumoniae was shown by several criteria to be due to a point mutation in the conjugative o(cat-tet) element found in the chromosomes of strains derived from BM6001, a clinical strain resistant to tetracycline and chloramphenicol. Strains carrying the mutation were transformed back to tetracycline resistance with the high efficiency of a point marker by donor deoxyribonucleic acids from its ancestral strain and from nine other clinical isolates of pneumococcus and by deoxyribonucleic acids from Group D Streptococcus faecalis and Group B Streptococcus agalactiae strains that also carry conjugative tet elements in their chromosomes. It was not transformed to resistance by tet plasmid deoxyribonucleic acids from either gram-negative or gram-positive species, except for one that carried transposon TN916, the conjugative tet element present in the chromosomes of some S. faecalis strains. The results showed that the tet determinants in conjugative elements of several streptococcal species share a high degree of deoxyribonucleic acid sequence homology and suggested that they differ from other tet genes.

Requirement of a Functional Flavin Mononucleotide Prenyltransferase for the Activity of a Bacterial Decarboxylase in a Heterologous Muconic Acid Pathway in Saccharomyces cerevisiae.

Science.gov (United States)

Weber, Heike E; Gottardi, Manuela; Brückner, Christine; Oreb, Mislav; Boles, Eckhard; Tripp, Joanna

2017-05-15

Biotechnological production of cis , cis -muconic acid from renewable feedstocks is an environmentally sustainable alternative to conventional, petroleum-based methods. Even though a heterologous production pathway for cis , cis -muconic acid has already been established in the host organism Saccharomyces cerevisiae , the generation of industrially relevant amounts of cis , cis -muconic acid is hampered by the low activity of the bacterial protocatechuic acid (PCA) decarboxylase AroY isomeric subunit C iso (AroY-C iso ), leading to secretion of large amounts of the intermediate PCA into the medium. In the present study, we show that the activity of AroY-C iso in S. cerevisiae strongly depends on the strain background. We could demonstrate that the strain dependency is caused by the presence or absence of an intact genomic copy of PAD1 , which encodes a mitochondrial enzyme responsible for the biosynthesis of a prenylated form of the cofactor flavin mononucleotide (prFMN). The inactivity of AroY-C iso in strain CEN.PK2-1 could be overcome by plasmid-borne expression of Pad1 or its bacterial homologue AroY subunit B (AroY-B). Our data reveal that the two enzymes perform the same function in decarboxylation of PCA by AroY-C iso , although coexpression of Pad1 led to higher decarboxylase activity. Conversely, AroY-B can replace Pad1 in its function in decarboxylation of phenylacrylic acids by ferulic acid decarboxylase Fdc1. Targeting of the majority of AroY-B to mitochondria by fusion to a heterologous mitochondrial targeting signal did not improve decarboxylase activity of AroY-C iso , suggesting that mitochondrial localization has no major impact on cofactor biosynthesis. IMPORTANCE In Saccharomyces cerevisiae , the decarboxylation of protocatechuic acid (PCA) to catechol is the bottleneck reaction in the heterologous biosynthetic pathway for production of cis , cis -muconic acid, a valuable precursor for the production of bulk chemicals. In our work, we demonstrate

Haematoxylin and eosin staining identifies medium to large bacterial aggregates with a reliable specificity: A comparative analysis of follicular bacterial aggregates in axillary biopsies using peptide nucleic acid-fluorescence in situ hybridization and haematoxylin and eosin staining.

Science.gov (United States)

Ring, Hans Christian; Theut Riis, Peter; Bay, Lene; Kallenbach, Klaus; Bjarnsholt, Thomas; Jemec, Gregor B E

2017-10-01

Although peptide nucleic acid (PNA), fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) are the reference tools in the study of bacterial aggregates/biofilms, it may also be rather time-consuming. This study aimed to investigate the sensitivity and specificity between bacterial aggregates identified by haematoxylin and eosin (HE) staining vs bacterial aggregates in corresponding PNA-FISH samples. Axillary biopsies were obtained in 24 healthy controls. HE-stained and PNA-FISH samples were investigated using traditional light microscopy and CLSM, respectively. The data demonstrate that HE staining identifies large bacterial aggregates (>10 μm) with a sensitivity of 0.43 and specificity of 1. The methods, however, are not equivalent as demonstrated by a McNemar's test (P=.04). Where bacterial aggregates >10 μm in diameter, HE staining may offer a rapid and practical low-cost tool to evaluate bacterial aggregates. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of different fermentation methods on bacterial cellulose and acid production by Gluconacetobacter xylinus in Cantonese-style rice vinegar.

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Fu, Liang; Chen, Siqian; Yi, Jiulong; Hou, Zongxia

2014-07-01

A strain of acidogenic bacterium was isolated from the fermentation liquid of Cantonese-style rice vinegar produced by traditional surface fermentation. 16S rDNA identification confirmed the bacterium as Gluconacetobacter xylinus, which synthesizes bacterial cellulose, and the acid productivity of the strain was investigated. In the study, the effects of the membrane integrity and the comparison of the air-liquid interface membrane with immerged membrane on total acidity, cellulose production, alcohol dehydrogenase (ADH) activity and number of bacteria were investigated. The cellulose membrane and the bacteria were observed under SEM for discussing their relationship. The correlations between oxygen consumption and total acid production rate were compared in surface and shake flask fermentation. The results showed the average acid productivity of the strain was 0.02g/(100mL/h), and the integrity of cellulose membrane in surface fermentation had an important effect on total acidity and cellulose production. With a higher membrane integrity, the total acidity after 144 h of fermentation was 3.75 g/100 mL, and the cellulose production was 1.71 g/100 mL after 360 h of fermentation. However, when the membrane was crushed by mechanical force, the total acidity and the cellulose production were as low as 0.36 g/100 mL and 0.14 g/100 mL, respectively. When the cellulose membrane was forced under the surface of fermentation liquid, the total acid production rate was extremely low, but the activity of ADH in the cellulose membrane was basically the same with the one above the liquid surface. The bacteria were mainly distributed in the cellulose membrane during the fermentation. The bacterial counts in surface fermentation were more than in the shake flask fermentation and G. xylinus consumed the substrate faster, in surface fermentation than in shake flask fermentation. The oxygen consumption rate and total acid production rate of surface fermentation were respectively 26

The Immediate and Delayed Post-Debridement Effects on Tissue Bacterial Wound Counts of Hypochlorous Acid Versus Saline Irrigation in Chronic Wounds

OpenAIRE

Hiebert, John?M.; Robson, Martin?C.

2016-01-01

Introduction: Wound debridement is considered essential in chronic wound management. Hypochlorous acid has been shown to be an effective agent in reducing wound bacterial counts in open wounds. Ultrasound-enabled wound debridement is an effective and efficient method of debridement. This study compared ultrasound irrigation with hypochlorous acid versus saline irrigation for wound debridement on pre- and postoperative wounds and determined regrowth of bacteria over 1 week period of time. Fina...

Host-Derived Sialic Acids Are an Important Nutrient Source Required for Optimal Bacterial Fitness In Vivo.

Science.gov (United States)

McDonald, Nathan D; Lubin, Jean-Bernard; Chowdhury, Nityananda; Boyd, E Fidelma

2016-04-12

A major challenge facing bacterial intestinal pathogens is competition for nutrient sources with the host microbiota.Vibrio cholerae is an intestinal pathogen that causes cholera, which affects millions each year; however, our knowledge of its nutritional requirements in the intestinal milieu is limited. In this study, we demonstrated that V. cholerae can grow efficiently on intestinal mucus and its component sialic acids and that a tripartite ATP-independent periplasmic SiaPQM strain, transporter-deficient mutant NC1777, was attenuated for colonization using a streptomycin-pretreated adult mouse model. In in vivo competition assays, NC1777 was significantly outcompeted for up to 3 days postinfection. NC1777 was also significantly outcompeted in in vitro competition assays in M9 minimal medium supplemented with intestinal mucus, indicating that sialic acid uptake is essential for fitness. Phylogenetic analyses demonstrated that the ability to utilize sialic acid was distributed among 452 bacterial species from eight phyla. The majority of species belonged to four phyla, Actinobacteria (members of Actinobacillus, Corynebacterium, Mycoplasma, and Streptomyces), Bacteroidetes (mainly Bacteroides, Capnocytophaga, and Prevotella), Firmicutes (members of Streptococcus, Staphylococcus, Clostridium, and Lactobacillus), and Proteobacteria (including Escherichia, Shigella, Salmonella, Citrobacter, Haemophilus, Klebsiella, Pasteurella, Photobacterium, Vibrio, and Yersinia species), mostly commensals and/or pathogens. Overall, our data demonstrate that the ability to take up host-derived sugars and sialic acid specifically allows V. cholerae a competitive advantage in intestinal colonization and that this is a trait that is sporadic in its occurrence and phylogenetic distribution and ancestral in some genera but horizontally acquired in others. Sialic acids are nine carbon amino sugars that are abundant on all mucous surfaces. The deadly human pathogen Vibrio cholerae contains

Bacterial membrane activity of a-peptide/b-peptoid chimeras: Influence of amino acid composition and chain length on the activity against different bacterial strains

DEFF Research Database (Denmark)

Hein-Kristensen, Line; Knapp, Kolja M; Franzyk, Henrik

2011-01-01

and subsequent killing is usually not tested. In this report, six α-peptide/β-peptoid chimeras were examined for the effect of amino acid/peptoid substitutions and chain length on the membrane perturbation and subsequent killing of food-borne and clinical bacterial isolates. RESULTS: All six AMP analogues...... acid only had a minor effect on MIC values, whereas chain length had a profound influence on activity. All chimeras were less active against Serratia marcescens (MICs above 46 μM). The chimeras were bactericidal and induced leakage of ATP from Staphylococcus aureus and S. marcescens with similar time...... of onset and reduction in the number of viable cells. EDTA pre-treatment of S. marcescens and E. coli followed by treatment with chimeras resulted in pronounced killing indicating that disintegration of the Gram-negative outer membrane eliminated innate differences in susceptibility. Chimera chain length...

Genetic Transformation of Streptococcus mutans

OpenAIRE

Perry, Dennis; Kuramitsu, Howard K.

1981-01-01

Three strains of Streptococcus mutans belonging to serotypes a, c, and f were transformed to streptomycin resistance by deoxyribonucleic acids derived from homologous and heterologous streptomycin-resistant strains of S. mutans and Streptococcus sanguis strain Challis. Homologous transformation of S. mutans was less efficient than heterologous transformation by deoxyribonucleic acids from other strains of S. mutans.

A New Sensitive GC-MS-based Method for Analysis of Dipicolinic Acid and Quantifying Bacterial Endospores in Deep Marine Subsurface Sediment

Science.gov (United States)

Fang, J.

2015-12-01

Marine sediments cover more than two-thirds of the Earth's surface and represent a major part of the deep biosphere. Microbial cells and microbial activity appear to be widespread in these sediments. Recently, we reported the isolation of gram-positive anaerobic spore-forming piezophilic bacteria and detection of bacterial endospores in marine subsurface sediment from the Shimokita coalbed, Japan. However, the modern molecular microbiological methods (e.g., DNA-based microbial detection techniques) cannot detect bacterial endospore, because endospores are impermeable and are not stained by fluorescence DNA dyes or by ribosomal RNA staining techniques such as catalysed reporter deposition fluorescence in situ hybridization. Thus, the total microbial cell abundance in the deep biosphere may has been globally underestimated. This emphasizes the need for a new cultivation independent approach for the quantification of bacterial endospores in the deep subsurface. Dipicolinic acid (DPA, pyridine-2,6-dicarboxylic acid) is a universal and specific component of bacterial endospores, representing 5-15wt% of the dry spore, and therefore is a useful indicator and quantifier of bacterial endospores and permits to estimate total spore numbers in the subsurface biosphere. We developed a sensitive analytical method to quantify DPA content in environmental samples using gas chromatography-mass spectrometry. The method is sensitive and more convenient in use than other traditional methods. We applied this method to analyzing sediment samples from the South China Sea (obtained from IODP Exp. 349) to determine the abundance of spore-forming bacteria in the deep marine subsurface sediment. Our results suggest that gram-positive, endospore-forming bacteria may be the "unseen majority" in the deep biosphere.

Presence of bacterial DNA and bacterial peptidoglycans in joints of patients with rheumatoid arthritis and other arthritides

NARCIS (Netherlands)

van der Heijden, I. M.; Wilbrink, B.; Tchetverikov, I.; Schrijver, I. A.; Schouls, L. M.; Hazenberg, M. P.; Breedveld, F. C.; Tak, P. P.

2000-01-01

The continuous presence of bacteria or their degraded antigens in the synovium may be involved in the pathogenesis of rheumatoid arthritis (RA). The aim of this study was to determine the presence of bacterial nucleic acids and bacterial cell wall constituents in the joints of patients with RA and

Revealing the compact structure of lactic acid bacterial hetero-exopolysaccharides by SAXS and DLS

DEFF Research Database (Denmark)

Khan, Sanaullah; Birch, Johnny; Harris, Pernille

2017-01-01

solution structures of three lactic acid bacterial hetero-exopolysaccharides (HePS-1, HePS-2 and HePS-3). Values of radius of gyration RG, cross-sectional radius of gyration RXS, approximate length L and hydrodynamic diameter were not directly proportional to the molar mass and indicated the HePSs adopted...... Galf residues significantly influence the conformation. Ab initio scattering modeling of HePS-2 and HePS-3 gave excellent curve fittings with χ2 of 0.43 and 0.34 for best-fit models, respectively, compatible with coil-like conformation. The findings disclose solution behaviour of HePS relevant...

Association between Folic Acid and Zinc Concentration with Incidence of Bacterial Vaginosis in The First Trimester of Pregnancy

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Noroyono Wibowo

2016-03-01

Full Text Available Bacterial vaginosis (BV in pregnancy is associated with the increase of adverse pregnancy outcomes such as premature rupture of membranes and preterm labor. One of the multifactorial causes of BV is thechange in vaginal immunity. Malnutrition, including micronutrient deficiency, increases the vulnerability toinfections. This study aim to investigate the association between folic acid and zinc concentration with theincidence of bacterial vaginosis in the first trimester of pregnancy. This descriptive cross sectional studyinvolved 139 mothers with first trimester pregnancy, aged between 17-39 years old. The study was conductedat dr. Cipto Mangunkusumo Hospital from September 2013 until August 2014. Vaginal secretions was sampledto diagnose BV under nugent criteria. Folic acid and zinc in the serum were measured. From 139 subject,18.7% (n=26 were found to be BV positive (nugent score =7. No deficiency of folic acid (<7 ng/mL and40.3% (n=56 of zinc deficiency (<60  µg/dL were found. Bivariate analysis used Kruskal-Wallis test betweenfolic acid and zinc concentration with BV incidence gives p value of 0.668 and 0.478 respectively. Prevalenceof BV in this study was 18.7%. The relation between the maternal statuses of folic acid with BV in the firsttrimester of pregnancy was not found. Keywords: bacterial vaginosis, folic acid, zinc, pregnancy.   Hubungan antara Kadar Asam Folat dan Seng terhadap KejadianVaginosis Bakteri pada Trimester Pertama Kehamilan Abstrak Bakterial vaginosis (BV pada kehamilan dihubungkan dengan meningkatnya luaran maternal yang buruk seperti ketuban pecah dini dan persalinan prematur. Penyebab BV multifaktor salah satunya adalahperubahan imunitas di vagina. Malnutrisi termasuk defisiensi mikronutrien meningkatkan kerentananterhadap infeksi. Studi ini dilakukan untuk mengetahui hubungan antara kadar asam folat dan seng terhadapkejadian vaginosis bakteri pada trimester pertama kehamilan. Penelitian ini merupakan studi

Superimposed Code Theoretic Analysis of Deoxyribonucleic Acid (DNA) Codes and DNA Computing

Science.gov (United States)

2010-01-01

DNA strand and its Watson - Crick complement can be used to perform mathematical computation. This research addresses how the...Acid dsDNA double stranded DNA MOSAIC Mobile Stream Processing Cluster PCR Polymerase Chain Reaction RAM Random Access Memory ssDNA single stranded DNA WC Watson – Crick A Adenine C Cytosine G Guanine T Thymine ...are 5′→3′ and strands with strikethrough are 3′→5′. A dsDNA duplex formed between a strand and its reverse complement is called a

Bacterial cell wall preservation during organic matter diagenesis in sediments off Peru

DEFF Research Database (Denmark)

Lomstein, Bente Aagaard; Niggemann, Jutta; Jørgensen, Bo Barker

BACTERIAL CELL WALL PRESERVATION DURING ORGANIC MATTER DIAGENESIS IN SEDIMENTS OFF PERU The spatial distribution of total hydrolysable amino acids, total hydrolysable amino sugars and amino acid enantiomers (D- and L-forms) were investigated in surface sediments at 20 stations in the Peru margin: 9......°45 S - 13º32 S. The objective of this study was to assess the preservation of bacterial cell walls during diagenesis of organic matter. Bacterial cell walls were traced by analysis of biomarkers uniquely produced by bacteria (D-amino acids and muramic acid). The diagenetic status of the sediments......:00 Presentation is given by student: No...

Hunger and microbiology: is a low gastric acid-induced bacterial overgrowth in the small intestine a contributor to malnutrition in developing countries?

Science.gov (United States)

Sarker, Shafiqul A; Ahmed, Tahmeed; Brüssow, Harald

2017-09-01

Underproduction of hydrochloric acid into the stomach is frequently encountered in subjects from developing countries. We explore the hypothesis that hypochlorhydria compromises the gastric barrier and favours bacterial overgrowth in the proximal parts of the small intestine where nutrient absorption takes place. Food calories are thus deviated into bacterial metabolism. In addition to an adequate caloric supply, correcting hypochlorhydria might be needed to decrease childhood malnutrition. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Yeast and bacterial diversity along a transect in an acidic, As-Fe rich environment revealed by cultural approaches.

Science.gov (United States)

Delavat, François; Lett, Marie-Claire; Lièvremont, Didier

2013-10-01

Acid mine drainages (AMDs) are often thought to harbour low biodiversity, yet little is known about the diversity distribution along the drainages. Using culture-dependent approaches, the microbial diversity from the Carnoulès AMD sediment was investigated for the first time along a transect showing progressive environmental stringency decrease. In total, 20 bacterial genera were detected, highlighting a higher bacterial diversity than previously thought. Moreover, this approach led to the discovery of 16 yeast species, demonstrating for the first time the presence of this important phylogenetic group in this AMD. All in all, the location of the microbes along the transect helps to better understand their distribution in a pollution gradient. Copyright © 2013 Elsevier B.V. All rights reserved.

Nanotechnology: Threats and Deterrent Opportunities by 2035

Science.gov (United States)

2010-02-17

22. 17 James Watson and Francis Crick discovered the structure of Deoxyribonucleic acid ( DNA ) in 1953. 18 Self-replication is when nanoscale machine...which then improves researchers’ understanding of critical, computationally intensive fields of study like DNA .17 These complementary scientific and...researchers’ clarity on critical medical issues like Deoxyribonucleic acid ( DNA ). 102 Omar Khayyam, Rubaiyat of Omar Khayyam (NY: Random House, 1947

Ultralong C100 mycolic acids support the assignment of Segniliparus as a new bacterial genus.

Directory of Open Access Journals (Sweden)

Sunhee Hong

Full Text Available Mycolic acid-producing bacteria isolated from the respiratory tract of human and non-human mammals were recently assigned as a distinct genus, Segniliparus, because they diverge from rhodococci and mycobacteria in genetic and chemical features. Using high accuracy mass spectrometry, we determined the chemical composition of 65 homologous mycolic acids in two Segniliparus species and separately analyzed the three subclasses to measure relative chain length, number and stereochemistry of unsaturations and cyclopropyl groups within each class. Whereas mycobacterial mycolate subclasses are distinguished from one another by R groups on the meromycolate chain, Segniliparus species synthesize solely non-oxygenated α-mycolates with high levels of cis unsaturation. Unexpectedly Segniliparus α-mycolates diverge into three subclasses based on large differences in carbon chain length with one bacterial culture producing mycolates that range from C58 to C100. Both the overall chain length (C100 and the chain length diversity (C42 are larger than previously seen for mycolic acid-producing organisms and provide direct chemical evidence for assignment of Segniliparus as a distinct genus. Yet, electron microscopy shows that the long and diverse mycolates pack into a typical appearing membrane. Therefore, these new and unexpected extremes of mycolic acid chemical structure raise questions about the modes of mycolic acid packing and folding into a membrane.

Does the high nucleic acid content of individual bacterial cells allow us to discriminate between active cells and inactive cells in aquatic systems?

Science.gov (United States)

Lebaron, P; Servais, P; Agogué, H; Courties, C; Joux, F

2001-04-01

The nucleic acid contents of individual bacterial cells as determined with three different nucleic acid-specific fluorescent dyes (SYBR I, SYBR II, and SYTO 13) and flow cytometry were compared for different seawater samples. Similar fluorescence patterns were observed, and bacteria with high apparent nucleic acid contents (HNA) could be discriminated from bacteria with low nucleic acid contents (LNA). The best discrimination between HNA and LNA cells was found when cells were stained with SYBR II. Bacteria in different water samples collected from seven freshwater, brackish water, and seawater ecosystems were prelabeled with tritiated leucine and then stained with SYBR II. After labeling and staining, HNA, LNA, and total cells were sorted by flow cytometry, and the specific activity of each cellular category was determined from leucine incorporation rates. The HNA cells were responsible for most of the total bacterial production, and the specific activities of cells in the HNA population varied between samples by a factor of seven. We suggest that nucleic acid content alone can be a better indicator of the fraction of growing cells than total counts and that this approach should be combined with other fluorescent physiological probes to improve detection of the most active cells in aquatic systems.

An unusual mode of DNA duplex association: Watson-Crick interaction of all-purine deoxyribonucleic acids.

Science.gov (United States)

Battersby, Thomas R; Albalos, Maria; Friesenhahn, Michel J

2007-05-01

Nucleic acid duplexes associating through purine-purine base pairing have been constructed and characterized in a remarkable demonstration of nucleic acids with mixed sequence and a natural backbone in an alternative duplex structure. The antiparallel deoxyribose all-purine duplexes associate specifically through Watson-Crick pairing, violating the nucleobase size-complementarity pairing convention found in Nature. Sequence-specific recognition displayed by these structures makes the duplexes suitable, in principle, for information storage and replication fundamental to molecular evolution in all living organisms. All-purine duplexes can be formed through association of purines found in natural ribonucleosides. Key to the formation of these duplexes is the N(3)-H tautomer of isoguanine, preferred in the duplex, but not in aqueous solution. The duplexes have relevance to evolution of the modern genetic code and can be used for molecular recognition of natural nucleic acids.

Cyanuric acid biodegradation by a mixed bacterial culture of Agrobacterium tumefaciens and Acinetobacter sp. in a packed bed biofilm reactor.

Science.gov (United States)

Galíndez-Nájera, S P; Llamas-Martínez, M A; Ruiz-Ordaz, N; Juárez-Ramírez, C; Mondragón-Parada, M E; Ahuatzi-Chacón, D; Galíndez-Mayer, J

2009-02-01

Cyanuric acid (1,3,5-triazine-2,4,6-triol [OOOT]) is a common biodegradation byproduct of triazinic herbicides, frequently accumulated in soils or water when supplementary carbon sources are absent. A binary bacterial culture able to degrade OOOT was selected through a continuous selection process accomplished in a chemostat fed with a mineral salt (MS) medium containing cyanuric acid as the sole carbon and nitrogen source. By sequence comparison of their 16S rDNA amplicons, bacterial strains were identified as Agrobacterium tumefaciens, and Acinetobacter sp. When the binary culture immobilized in a packed bed reactor (PBR) was fed with MS medium containing OOOT (50 mg L(-1)), its removal efficiencies were about 95%; when it was fed with OOOT plus glucose (120 mg L(-1)) as a supplementary carbon source, its removal efficiencies were closer to 100%. From sessile cells, attached to PBR porous support, or free cells present in the outflowing medium, DNA was extracted and used for Random Amplification of Polymorphic DNA analysis. Electrophoretic patterns obtained were compared to those of pure bacterial strains, a clear predominance of A. tumefaciens in PBR was observed. Although in continuous suspended cell culture, a stable binary community could be maintained, the attachment capability of A. tumefaciens represented a selective advantage over Acinetobacter sp. in the biofilm reactor, favoring its predominance in the porous stone support.

Changes in the protein fraction of Merluccius bilinearis muscle under lactic acid bacterial fermentation using a Lactobacillus Acidophilus starter culture (ESP

Directory of Open Access Journals (Sweden)

Luis J. Elizondo

2016-03-01

Full Text Available The effect of lactic acid bacterial fermentation on the protein fraction of Merluccius bilinearis muscle was evaluated. The non-protein fraction increased progressively with corresponding decreases in the percentage protein (dry weight indicating proteolytic activity during fermentation. Significant increases in the percentages of the amino acids cystine, isoleucine, phenylalanine and tyrosine were observed after two months of fermentation. Percentages of arginine decreased significantly after one week and again after two months of fermentation.

Evaluation of bacterial growth inhibition by mercaptopropionic acid in metallo-β-lactamase detection on multidrug-resistant Acinetobacter baumannii.

Science.gov (United States)

Mayer, Letícia Eichstaedt; Hörner, Rosmari; Tizotti, Maisa Kräulich; Martini, Rosiéli; Roehrs, Magda Cristina Souza Marques; Kempfer, Cláudia Barbisan

2012-01-01

Metallo-β-lactamase (MBL) has been reported all over the world. The inhibitory effect of mercaptopropionic acid (MPA) on bacterial growth was evaluated by comparison between disk diffusion and broth dilution methodology with determination of the minimum inhibitory concentration (MIC) for multidrug-resistant Acinetobacter baumanni strains. MPA significantly inhibited growth of the strains. The use of MPA can affect the results in phenotypic methods of MBL detection.

DNA-mediated bacterial aggregation is dictated by acid-base interactions

NARCIS (Netherlands)

Das, Theerthankar; Krom, Bastiaan P.; van der Mei, Henny C.; Busscher, Henk J.; Sharma, Prashant K.

2011-01-01

Extracellular DNA (eDNA) plays a significant role in bacterial biofilm formation and aggregation. Here, for the first time, we present a physico-chemical analysis of the DNA-mediated aggregation for three bacterial strains (Streptococcus mutans LT11, Pseudomonas aeruginosa PAO1 and Staphylococcus

Evaluation of bacterial growth inhibition by mercaptopropionic acid in metallo-β-lactamase detection on multidrug-resistant Acinetobacter baumannii

Directory of Open Access Journals (Sweden)

Letícia Eichstaedt Mayer

2012-04-01

Full Text Available INTRODUCTION: Metallo-β-lactamase (MBL has been reported all over the world. METHODS: The inhibitory effect of mercaptopropionic acid (MPA on bacterial growth was evaluated by comparison between disk diffusion and broth dilution methodology with determination of the minimum inhibitory concentration (MIC for multidrug-resistant Acinetobacter baumanni strains. RESULTS: MPA significantly inhibited growth of the strains. CONCLUSIONS: The use of MPA can affect the results in phenotypic methods of MBL detection.

Bacterial Cell Mechanics.

Science.gov (United States)

Auer, George K; Weibel, Douglas B

2017-07-25

Cellular mechanical properties play an integral role in bacterial survival and adaptation. Historically, the bacterial cell wall and, in particular, the layer of polymeric material called the peptidoglycan were the elements to which cell mechanics could be primarily attributed. Disrupting the biochemical machinery that assembles the peptidoglycan (e.g., using the β-lactam family of antibiotics) alters the structure of this material, leads to mechanical defects, and results in cell lysis. Decades after the discovery of peptidoglycan-synthesizing enzymes, the mechanisms that underlie their positioning and regulation are still not entirely understood. In addition, recent evidence suggests a diverse group of other biochemical elements influence bacterial cell mechanics, may be regulated by new cellular mechanisms, and may be triggered in different environmental contexts to enable cell adaptation and survival. This review summarizes the contributions that different biomolecular components of the cell wall (e.g., lipopolysaccharides, wall and lipoteichoic acids, lipid bilayers, peptidoglycan, and proteins) make to Gram-negative and Gram-positive bacterial cell mechanics. We discuss the contribution of individual proteins and macromolecular complexes in cell mechanics and the tools that make it possible to quantitatively decipher the biochemical machinery that contributes to bacterial cell mechanics. Advances in this area may provide insight into new biology and influence the development of antibacterial chemotherapies.

Porous rod-like MgO complex membrane with good anti-bacterial activity directed by conjugated linolenic acid polymer

Energy Technology Data Exchange (ETDEWEB)

Wang, Hua-Jie, E-mail: wanghuajie972001@163.com; Chen, Meng [Henan Normal University, College of Chemistry and Chemical Engineering (China); Mi, Li-Wei, E-mail: mlwzzu@163.com [Zhongyuan University of Technology, Center for Advanced Materials Research (China); Shi, Li-Hua [Anyang 101 Education Center (China); Cao, Ying, E-mail: caoying1130@sina.com [Zhongyuan University of Technology, Center for Advanced Materials Research (China)

2016-02-15

The problem of infection in the tissue engineering substitutes is driving us to seek new coating materials. We previously found that conjugated linolenic acid (CLnA) has well biocompatibility and excellent membrane-forming property. The objective of this study is to endow the anti-bacterial activity to CLnA membra ne by linking with MgO. The results showed that the CLnA polymer membrane can be loaded with porous rod-like MgO and such complex membrane showed anti-bacterial sensitivity against gram-positive bacteria (Staphylococcus aureus) even at the low concentration (0.15 μg/mm{sup 2}). In the present study, the best zone of inhibition got to 18.2 ± 0.8 mm when the amount of MgO reach 2.42 ± 0.58 μg/mm{sup 2}. It was deduced that the porous rod-like structure of MgO was directed by CLnA in its polymerization process. Such CLnA/MgO complex membrane can be helpful in the tissue engineering, medicine, food engineering, food preservation, etc. on the basis of its good anti-bacterial activity.

Activity and Phylogenetic Diversity of Bacterial Cells with High and Low Nucleic Acid Content and Electron Transport System Activity in an Upwelling Ecosystem

OpenAIRE

Longnecker, K.; Sherr, B. F.; Sherr, E. B.

2005-01-01

We evaluated whether bacteria with higher cell-specific nucleic acid content (HNA) or an active electron transport system, i.e., positive for reduction of 5-cyano-2,3-ditolyl tetrazolium chloride (CTC), were responsible for the bulk of bacterioplankton metabolic activity. We also examined whether the phylogenetic diversity of HNA and CTC-positive cells differed from the diversity of Bacteria with low nucleic acid content (LNA). Bacterial assemblages were sampled both in eutrophic shelf waters...

Rapid brain death caused by a cerebellar abscess with Fusobacterium nucleatum in a young man with drug abuse: a case report.

Science.gov (United States)

Hischebeth, Gunnar T R; Keil, Vera C; Gentil, Katrin; Boström, Azize; Kuchelmeister, Klaus; Bekeredjian-Ding, Isabelle

2014-06-10

Fusobacterium nucleatum is a strict anaerobic microorganism that causes disease entities such as periodontal and soft tissue abscesses, pulmonary and intraabdominal infections and very rarely intracerebral infections. Here, we report the rare case of a previously healthy 25-year-old German man with a cerebellar abscess caused by Fusobacterium nucleatum that resulted in rapid brain death. Toxicological screening showed positivity for amphetamines and cannabis. The diagnosis was obtained by polymerase chain reaction amplification of bacterial deoxyribonucleic acid in cerebrospinal fluid. In drug users clinicians should think about rare causes of brain abscesses/meningitis. Early diagnosis is necessary and justifies the use of molecular techniques.

Isolation of deoxyribonucleic acids (A Review)

International Nuclear Information System (INIS)

Garcia Pineda, M. de

1974-01-01

The criteria of choice in this Review have been to gather some of the last advances in the methodology of DNAs isolation; also the description of the generally accepted procedures has been emphasized. Only papers published before March 1974 are reviewed, because this work has been finished during this month. (Author) 109 refs

The deoxyribonucleic acid of Micrococcus radiodurans

Science.gov (United States)

Schein, Arnold H.

1966-01-01

The DNA of Micrococcus radiodurans was prepared by three methods. Although the recovery of DNA varied considerably, the percentage molar base ratios of the DNA from the three preparations were essentially the same: guanine, 33±2; adenine, 18±1; cytosine, 33±2; thymine, 17±1. Base compositions calculated from Tm values and from density in caesium chloride gradients also yielded guanine+cytosine contents of 66 and 68% of total bases respectively. No unusual bases were observed. The S20,w values were characteristic of high-molecular-weight DNA. Electron microscopy showed the purified DNA in long strands; occasionally these were coiled. Images(a)(b)(c)(d)(e)Fig. 1. PMID:16742439

Extremophiles in Mineral Sulphide Heaps: Some Bacterial Responses to Variable Temperature, Acidity and Solution Composition

Directory of Open Access Journals (Sweden)

Helen R. Watling

2015-07-01

Full Text Available In heap bioleaching, acidophilic extremophiles contribute to enhanced metal extraction from mineral sulphides through the oxidation of Fe(II and/or reduced inorganic sulphur compounds (RISC, such as elemental sulphur or mineral sulphides, or the degradation of organic compounds derived from the ore, biota or reagents used during mineral processing. The impacts of variable solution acidity and composition, as well as temperature on the three microbiological functions have been examined for up to four bacterial species found in mineral sulphide heaps. The results indicate that bacteria adapt to sufficiently high metal concentrations (Cu, Ni, Co, Zn, As to allow them to function in mineral sulphide heaps and, by engaging alternative metabolic pathways, to extend the solution pH range over which growth is sustained. Fluctuating temperatures during start up in sulphide heaps pose the greatest threat to efficient bacterial colonisation. The large masses of ores in bioleaching heaps mean that high temperatures arising from sulphide oxidation are hard to control initially, when the sulphide content of the ore is greatest. During that period, mesophilic and moderately thermophilic bacteria are markedly reduced in both numbers and activity.

Disinfection efficiency of peracetic acid (PAA): inactivation of coliphages and bacterial indicators in a municipal wastewater plant.

Science.gov (United States)

Zanetti, F; De Luca, G; Sacchetti, R; Stampi, S

2007-11-01

The aim of the study was to assess the efficiency of low doses of peracetic acid against viral and bacterial indicators in wastewater and to evaluate if the treatment allows regulatory requirements to be satisfied. A total of 31 samplings were carried out, each involving the collection of secondary effluent and of effluent disinfected with 1.2 or 1.5 mg l(-1) of peracetic acid (contact time 20 minutes). In each sample were measured: somatic coliphages, F-specific RNA bacteriophages, Escherichia coli, total and faecal coliforms, enterococci. Peracetic acid disinfection showed significant differences between the reductions of the microorganisms tested: E. coli showed the highest reduction (1.78 and 2.43 Log respectively with 1.2 and 1.5 mg l(-1) of peracetic acid) and phages the lowest (ranging between 0.52 and 0.60 Log). Only a concentration of 1.5 mg l(-1) of peracetic acid would enable the effluent to be discharged into surface waters in compliance with Italian regulations. The variability of microbial resistance against the peracetic acid disinfection treatment, underlines the importance of assessing disinfection efficiency by using more than one indicator microorganism. The detection of E. coli could be usefully accompanied by tests for more resistant microorganisms such as enterococci or coliphages. In conclusion, peracetic acid can be used for the disinfection of effluents even at low doses, with the advantage of reducing costs and preventing the formation of significant amounts of genotoxic by-products.

Re-engineering of Bacterial Luciferase; For New Aspects of Bioluminescence.

Science.gov (United States)

Kim, Da-Som; Choi, Jeong-Ran; Ko, Jeong-Ae; Kim, Kangmin

2018-01-01

Bacterial luminescence is the end-product of biochemical reactions catalyzed by the luciferase enzyme. Nowadays, this fascinating phenomenon has been widely used as reporter and/or sensors to detect a variety of biological and environmental processes. The enhancement or diversification of the luciferase activities will increase the versatility of bacterial luminescence. Here, to establish the strategy for luciferase engineering, we summarized the identity and relevant roles of key amino acid residues modulating luciferase in Vibrio harveyi, a model luminous bacterium. The current opinions on crystal structures and the critical amino acid residues involved in the substrate binding sites and unstructured loop have been delineated. Based on these, the potential target residues and/or parameters for enzyme engineering were also suggested in limited scale. In conclusion, even though the accurate knowledge on the bacterial luciferase is yet to be reported, the structure-guided site-directed mutagenesis approaches targeting the regulatory amino acids will provide a useful platform to re-engineer the bacterial luciferase in the future. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

[Spontaneous bacterial peritonitis].

Science.gov (United States)

Velkey, Bálint; Vitális, Eszter; Vitális, Zsuzsanna

2017-01-01

Spontaneous bacterial peritonitis occurs most commonly in cirrhotic patients with ascites. Pathogens get into the circulation by intestinal translocation and colonize in peritoneal fluid. Diagnosis of spontaneous bacterial peritonitis is based on elevated polymorphonuclear leukocyte count in the ascites (>0,25 G/L). Ascites culture is often negative but aids to get information about antibiotic sensitivity in positive cases. Treatment in stable patient can be intravenous then orally administrated ciprofloxacin or amoxicillin/clavulanic acid, while in severe cases intravenous III. generation cephalosporin. Nosocomial spontaneous bacterial peritonitis often caused by Gram-positive bacteria and multi-resistant pathogens can also be expected thus carbapenem should be the choice of the empiric treatment. Antibiotic prophylaxis should be considered. Norfloxacin is used most commonly, but changes are expected due to increase in quinolone resistance. As a primary prophylaxis, a short-term antibiotic treatment is recommended after gastrointestinal bleeding for 5 days, while long-term prophylaxis is for patients with low ascites protein, and advanced disease (400 mg/day). Secondary prophylaxis is recommended for all patients recovered from spontaneous bacterial peritonitis. Due to increasing antibiotic use of antibiotics prophylaxis is debated to some degree. Orv. Hetil., 2017, 158(2), 50-57.

PHAGE RESISTANT LACTIC ACID BACTERIAL MUTANTS

DEFF Research Database (Denmark)

2001-01-01

Method of obtaining mutated lactic acid bacteria having a reduced susceptibility towards attack by bacteriophages, the method comprising mutating a gene involved in the pyrimidine metabolism, including pyrG encoding CTP synthetase. Such lactic acid bacteria are useful in starter cultures...

Inhibition of bacterial DD-peptidases (penicillin-binding proteins) in membranes and in vivo by peptidoglycan-mimetic boronic acids.

Science.gov (United States)

Dzhekieva, Liudmila; Kumar, Ish; Pratt, R F

2012-04-03

The DD-peptidases or penicillin-binding proteins (PBPs) catalyze the final steps of bacterial peptidoglycan biosynthesis and are inhibited by the β-lactam antibiotics. There is at present a question of whether the active site structure and activity of these enzymes is the same in the solubilized (truncated) DD-peptidase constructs employed in crystallographic and kinetics studies as in membrane-bound holoenzymes. Recent experiments with peptidoglycan-mimetic boronic acids have suggested that these transition state analogue-generating inhibitors may be able to induce reactive conformations of these enzymes and thus inhibit strongly. We have now, therefore, measured the dissociation constants of peptidoglycan-mimetic boronic acids from Escherichia coli and Bacillus subtilis PBPs in membrane preparations and, in the former case, in vivo, by means of competition experiments with the fluorescent penicillin Bocillin Fl. The experiments showed that the boronic acids bound measurably (K(i) DD-peptidase inhibitors are more or less effective in vivo than in homogeneous solution.

Analysis of the bacterial community composition in acidic well water used for drinking in Guinea-Bissau, West Africa.

Science.gov (United States)

Machado, Ana; Bordalo, Adriano A

2014-08-01

Potable water is a resource out of reach for millions worldwide, and the available water may be chemically and microbiologically compromised. This is particularly acute in Africa, where water-networks may be non-existent or restricted to a small fraction of the urban population, as in the case of Guinea-Bissau, West Africa. This study was carried out seasonally in Bolama (11°N), where unprotected hand-dug wells with acidic water are the sole source of water for the population. We inspected the free-living bacterial community dynamics by automated rRNA intergenic spacer analyses, quantitative polymerase chain reaction and cloning approaches. The results revealed a clear seasonal shift in bacterial assemblage composition and microbial abundance within the same sampling site. Temperature, pH and turbidity, together with the infiltration and percolation of surface water, which takes place in the wet season, seemed to be the driving factors in the shaping and selection of the bacterial community and deterioration of water quality. Analysis of 16S rDNA sequences revealed several potential pathogenic bacteria and uncultured bacteria associated with water and sediments, corroborating the importance of a culture-independent approach in drinking water monitoring. Copyright © 2014. Published by Elsevier B.V.

Antibiofilm Properties of Acetic Acid

DEFF Research Database (Denmark)

Bjarnsholt, Thomas; Alhede, Morten; Jensen, Peter Østrup

2014-01-01

Bacterial biofilms are known to be extremely tolerant toward antibiotics and other antimicrobial agents. These biofilms cause the persistence of chronic infections. Since antibiotics rarely resolve these infections, the only effective treatment of chronic infections is surgical removal of the inf......Bacterial biofilms are known to be extremely tolerant toward antibiotics and other antimicrobial agents. These biofilms cause the persistence of chronic infections. Since antibiotics rarely resolve these infections, the only effective treatment of chronic infections is surgical removal...... of the infected implant, tissue, or organ and thereby the biofilm. Acetic acid is known for its antimicrobial effect on bacteria in general, but has never been thoroughly tested for its efficacy against bacterial biofilms. In this article, we describe complete eradication of both Gram-positive and Gram......-negative biofilms using acetic acid both as a liquid and as a dry salt. In addition, we present our clinical experience of acetic acid treatment of chronic wounds. In conclusion, we here present the first comprehensive in vitro and in vivo testing of acetic acid against bacterial biofilms....

Is intravesical instillation of hyaluronic acid and chondroitin sulfate useful in preventing recurrent bacterial cystitis? A multicenter case control analysis

OpenAIRE

Giorgio Gugliotta; Gloria Calagna; Giorgio Adile; Salvatore Polito; Salvatore Saitta; Patrizia Speciale; Stefano Palomba; Antonino Perino; Roberta Granese; Biagio Adile

2015-01-01

Objective: Urinary tract infections (UTIs) are common in the female population and, over a lifetime, about half of women have at least one episode of UTI requiring antibiotic therapy. The aim of the current study was to compare two different strategies for preventing recurrent bacterial cystitis: intravesical instillation of hyaluronic acid (HA) plus chondroitin sulfate (CS), and antibiotic prophylaxis with sulfamethoxazole plus trimethoprim. Materials and methods: This was a retrospective...

Fluorescent detection of dipicolinic acid as a biomarker of bacterial spores using lanthanide-chelated gold nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Donmez, Mert [Department of Chemistry, Faculty of Art and Sciences, Duzce University, Duzce 81620 (Turkey); Yilmaz, M. Deniz, E-mail: deniz.yilmaz@gidatarim.edu.tr [Department of Bioengineering, Faculty of Engineering and Architecture, Konya Food and Agriculture University, Konya 42080 (Turkey); Kilbas, Benan, E-mail: benankilbas@duzce.edu.tr [Department of Chemistry, Faculty of Art and Sciences, Duzce University, Duzce 81620 (Turkey)

2017-02-15

Highlights: • The nanosensors based on gold nanoparticles functionalized with lanthanide complexes were synthesized. • The nanosensors selectively and sensitively detected DPA, a biomarker of bacterial spores. • Ratiometric sensing of DPA by a ternary complex was achieved by ligand displacement strategy. - Abstract: Gold nanoparticles (GNPs) functionalized with ethylenediamine-lanthanide complexes (Eu-GNPs and Tb-GNPs) were used for the selective fluorescent detection of dipicolinic acid (DPA), a unique biomarker of bacterial spores, in water. Particles were characterized by transmission electron microscopy and zeta potential measurements. The coordination of DPA to the lanthanides resulted in the enhancement of the fluorescence. A selective response to DPA was observed over the nonselective binding of aromatic ligands. The ligand displacement strategy were also employed for the ratiometric fluorescent detection of DPA. 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedion (TFNB) was chosen as an antenna to synthesize ternary complexes. The addition of DPA on EuGNP:TFNB ternary complex quenched the initial emission of the complex at 615 nm and increased the TFNB emission at 450 nm when excited at 350 nm. The results demonstrated that the ratiometric fluorescent detection of DPA was achieved by ligand displacement strategy.

Benzene-1,3-dicarboxylic acid 2,5-dimethylpyrrole derivatives as multiple inhibitors of bacterial Mur ligases (MurC-MurF).

Science.gov (United States)

Perdih, Andrej; Hrast, Martina; Barreteau, Hélène; Gobec, Stanislav; Wolber, Gerhard; Solmajer, Tom

2014-08-01

Enzymes catalyzing the biosynthesis of bacterial peptidoglycan represent traditionally a collection of highly selective targets for novel antibacterial drug design. Four members of the bacterial Mur ligase family-MurC, MurD, MurE and MurF-are involved in the intracellular steps of peptidoglycan biosynthesis, catalyzing the synthesis of the peptide moiety of the Park's nucleotide. In our previous virtual screening campaign, a chemical class of benzene-1,3-dicarboxylic acid 2,5-dimethylpyrrole derivatives exhibiting dual MurD/MurE inhibition properties was discovered. In the present study we further investigated this class of compounds by performing inhibition assays on all four Mur ligases (MurC-MurF). Furthermore, molecular dynamics (MD) simulation studies of one of the initially discovered compound 1 were performed to explore its geometry as well as its energetic behavior based on the Linear Interaction Energy (LIE) method. Further in silico virtual screening (VS) experiments based on the parent active compound 1 were conducted to optimize the discovered series. Selected hits were assayed against all Escherichia coli MurC-MurF enzymes in biochemical inhibition assays and molecules 10-14 containing benzene-1,3-dicarboxylic acid 2,5-dimethylpyrrole coupled with five member-ring rhodanine moiety were found to be multiple inhibitors of the whole MurC-MurF cascade of bacterial enzymes in the micromolar range. Steady-state kinetics studies suggested this class to act as competitive inhibitors of the MurD enzyme towards d-Glu. These compounds represent novel valuable starting point in the development of novel antibacterial agents. Copyright © 2014 Elsevier Ltd. All rights reserved.

Synthesis of Na-acetyl-ornithine and N-succinyl-diaminopimelic acid analogs as potential inhibitors of bacterial enzymes ArgE and DapE

Czech Academy of Sciences Publication Activity Database

Hlaváček, Jan; Pícha, Jan; Jiráček, Jiří; Vaněk, Václav; Gilner, D.; Slaninová, Jiřina; Fučík, Vladimír; Holz, R. C.

2009-01-01

Roč. 103, č. 11 (2009), s. 952-952 ISSN 0009-2770. [Pokroky v organické, bioorganické a farmaceutické chemii /44./. 27.11.2009-29.11.2009, Liblice] R&D Projects: GA AV ČR IAA400550614 Institutional research plan: CEZ:AV0Z40550506 Keywords : amino acid derivatives * bacterial enzymes * inhibition Subject RIV: CC - Organic Chemistry

Activity and phylogenetic diversity of bacterial cells with high and low nucleic acid content and electron transport system activity in an upwelling ecosystem.

Science.gov (United States)

Longnecker, K; Sherr, B F; Sherr, E B

2005-12-01

We evaluated whether bacteria with higher cell-specific nucleic acid content (HNA) or an active electron transport system, i.e., positive for reduction of 5-cyano-2,3-ditolyl tetrazolium chloride (CTC), were responsible for the bulk of bacterioplankton metabolic activity. We also examined whether the phylogenetic diversity of HNA and CTC-positive cells differed from the diversity of Bacteria with low nucleic acid content (LNA). Bacterial assemblages were sampled both in eutrophic shelf waters and in mesotrophic offshore waters in the Oregon coastal upwelling region. Cytometrically sorted HNA, LNA, and CTC-positive cells were assayed for their cell-specific [3H]leucine incorporation rates. Phylogenetic diversity in sorted non-radioactively labeled samples was assayed using denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA genes. Cell-specific rates of leucine incorporation of HNA and CTC-positive cells were on average only slightly greater than the cell-specific rates of LNA cells. HNA cells accounted for most bacterioplankton substrate incorporation due to high abundances, while the low abundances of CTC-positive cells resulted in only a small contribution by these cells to total bacterial activity. The proportion of the total bacterial leucine incorporation attributable to LNA cells was higher in offshore regions than in shelf waters. Sequence data obtained from DGGE bands showed broadly similar phylogenetic diversity across HNA, LNA, and CTC-positive cells, with between-sample and between-region variability in the distribution of phylotypes. Our results suggest that LNA bacteria are not substantially different from HNA bacteria in either cell-specific rates of substrate incorporation or phylogenetic composition and that they can be significant contributors to bacterial metabolism in the sea.

TolC is important for bacterial survival and oxidative stress response in Salmonella enterica serovar Choleraesuis in an acidic environment.

Science.gov (United States)

Lee, Jen-Jie; Wu, Ying-Chen; Kuo, Chih-Jung; Hsuan, Shih-Ling; Chen, Ter-Hsin

2016-09-25

The outer membrane protein TolC, which is one of the key components of several multidrug efflux pumps, is thought to be involved in various independent systems in Enterobacteriaceae. Since the acidic environment of the stomach is an important protection barrier against foodborne pathogen infections in hosts, we evaluated whether TolC played a role in the acid tolerance of Salmonella enterica serovar Choleraesuis. Comparison of the acid tolerance of the tolC mutant and the parental wild-type strain showed that the absence of TolC limits the ability of Salmonella to sustain life under extreme acidic conditions. Additionally, the mutant exhibited morphological changes during growth in an acidic medium, leading to the conflicting results of cell viability measured by spectrophotometry and colony-forming unit counting. Reverse-transcriptional-PCR analysis indicated that acid-related molecules, apparatus, or enzymes and oxidation-induced factors were significantly affected by the acidic environment in the null-tolC mutant. The elongated cellular morphology was restored by adding antioxidants to the culture medium. Furthermore, we found that increased cellular antioxidative activity provides an overlapping protection against acid killing, demonstrating the complexity of the bacterial acid stress response. Our findings reinforce the multifunctional characteristics of TolC in acid tolerance or oxidative stress resistance and support the correlative protection mechanism between oxygen- and acid-mediated stress responses in Salmonella enterica serovar Choleraesuis. Copyright © 2016 Elsevier B.V. All rights reserved.

Fertilization Shapes Bacterial Community Structure by Alteration of Soil pH

Directory of Open Access Journals (Sweden)

Yuting Zhang

2017-07-01

Full Text Available Application of chemical fertilizer or manure can affect soil microorganisms directly by supplying nutrients and indirectly by altering soil pH. However, it remains uncertain which effect mostly shapes microbial community structure. We determined soil bacterial diversity and community structure by 454 pyrosequencing the V1-V3 regions of 16S rRNA genes after 7-years (2007–2014 of applying chemical nitrogen, phosphorus and potassium (NPK fertilizers, composted manure or their combination to acidic (pH 5.8, near-neutral (pH 6.8 or alkaline (pH 8.4 Eutric Regosol soil in a maize-vegetable rotation in southwest China. In alkaline soil, nutrient sources did not affect bacterial Operational Taxonomic Unit (OTU richness or Shannon diversity index, despite higher available N, P, K, and soil organic carbon in fertilized than in unfertilized soil. In contrast, bacterial OTU richness and Shannon diversity index were significantly lower in acidic and near-neutral soils under NPK than under manure or their combination, which corresponded with changes in soil pH. Permutational multivariate analysis of variance showed that bacterial community structure was significantly affected across these three soils, but the PCoA ordination patterns indicated the effect was less distinct among nutrient sources in alkaline than in acidic and near-neural soils. Distance-based redundancy analysis showed that bacterial community structures were significantly altered by soil pH in acidic and near-neutral soils, but not by any soil chemical properties in alkaline soil. The relative abundance (% of most bacterial phyla was higher in near-neutral than in acidic or alkaline soils. The most dominant phyla were Proteobacteria (24.6%, Actinobacteria (19.7%, Chloroflexi (15.3% and Acidobacteria (12.6%; the medium dominant phyla were Bacterioidetes (5.3%, Planctomycetes (4.8%, Gemmatimonadetes (4.5%, Firmicutes (3.4%, Cyanobacteria (2.1%, Nitrospirae (1.8%, and candidate division TM7 (1

Fertilization Shapes Bacterial Community Structure by Alteration of Soil pH.

Science.gov (United States)

Zhang, Yuting; Shen, Hong; He, Xinhua; Thomas, Ben W; Lupwayi, Newton Z; Hao, Xiying; Thomas, Matthew C; Shi, Xiaojun

2017-01-01

Application of chemical fertilizer or manure can affect soil microorganisms directly by supplying nutrients and indirectly by altering soil pH. However, it remains uncertain which effect mostly shapes microbial community structure. We determined soil bacterial diversity and community structure by 454 pyrosequencing the V1-V3 regions of 16S rRNA genes after 7-years (2007-2014) of applying chemical nitrogen, phosphorus and potassium (NPK) fertilizers, composted manure or their combination to acidic (pH 5.8), near-neutral (pH 6.8) or alkaline (pH 8.4) Eutric Regosol soil in a maize-vegetable rotation in southwest China. In alkaline soil, nutrient sources did not affect bacterial Operational Taxonomic Unit (OTU) richness or Shannon diversity index, despite higher available N, P, K, and soil organic carbon in fertilized than in unfertilized soil. In contrast, bacterial OTU richness and Shannon diversity index were significantly lower in acidic and near-neutral soils under NPK than under manure or their combination, which corresponded with changes in soil pH. Permutational multivariate analysis of variance showed that bacterial community structure was significantly affected across these three soils, but the PCoA ordination patterns indicated the effect was less distinct among nutrient sources in alkaline than in acidic and near-neural soils. Distance-based redundancy analysis showed that bacterial community structures were significantly altered by soil pH in acidic and near-neutral soils, but not by any soil chemical properties in alkaline soil. The relative abundance (%) of most bacterial phyla was higher in near-neutral than in acidic or alkaline soils. The most dominant phyla were Proteobacteria (24.6%), Actinobacteria (19.7%), Chloroflexi (15.3%) and Acidobacteria (12.6%); the medium dominant phyla were Bacterioidetes (5.3%), Planctomycetes (4.8%), Gemmatimonadetes (4.5%), Firmicutes (3.4%), Cyanobacteria (2.1%), Nitrospirae (1.8%), and candidate division TM7 (1

Identification of Lactic Acid Bacteria and Propionic Acid Bacteria using FTIR Spectroscopy and Artificial Neural Networks

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Beata Nalepa

2012-01-01

Full Text Available In the present study, lactic acid bacteria and propionic acid bacteria have been identified at the genus level with the use of artificial neural networks (ANNs and Fourier transform infrared spectroscopy (FTIR. Bacterial strains of the genera Lactobacillus, Lactococcus, Leuconostoc, Streptococcus and Propionibacterium were analyzed since they deliver health benefits and are routinely used in the food processing industry. The correctness of bacterial identification by ANNs and FTIR was evaluated at two stages. At first stage, ANNs were tested based on the spectra of 66 reference bacterial strains. At second stage, the evaluation involved 286 spectra of bacterial strains isolated from food products, deposited in our laboratory collection, and identified by genus-specific PCR. ANNs were developed based on the spectra and their first derivatives. The most satisfactory results were reported for the probabilistic neural network, which was built using a combination of W5W4W3 spectral ranges. This network correctly identified the genus of 95 % of the lactic acid bacteria and propionic acid bacteria strains analyzed.

Bacterial community dynamics and product distribution during pH-adjusted fermentation of vegetable wastes.

Science.gov (United States)

Ye, N-F; Lü, F; Shao, L-M; Godon, J-J; He, P-J

2007-10-01

To estimate the effect of pH on the structures of bacterial community during fermentation of vegetable wastes and to investigate the relationship between bacterial community dynamics and product distribution. The bacterial communities in five batch tests controlled at different pH values [uncontrolled (about pH 4), 5, 6, 7 and 8] were monitored by denaturing gradient gel electrophoresis (DGGE) and single-strand conformation polymorphism (SSCP). The two fingerprinting methods provided consistent results and principal component analysis indicated a close similarity of bacterial community at pH 7 and 8 in addition to those at pH 4-6. This clustering also corresponded to dominant metabolic pathway. Thus, pH 7-8 shifted from alcohol-forming to acid-forming, especially butyric acid, whereas both alcohol-forming and acid-forming dominated at pH 5-6, and at pH 4, fermentation was inhibited. Shannon-weaver index was calculated to analyse the DGGE profiles, which revealed that the bacterial diversities at pH 7 and 8 were the highest while those at pH 5 and 4 (uncontrolled) were the lowest. According to sequencing results of the bands excised from DGGE gels, lactic acid bacteria and Clostridium sp. were predominant at all pH values, but varieties in species were observed as pH changed and time prolonged. The bacterial community during fermentation was materially influenced by pH and the diverse product distribution was related to the shift of different bacterial population. The study reveals that the impact of pH on fermentation product distribution is implemented primarily by changes of bacterial community. It also provides information about the comparison of two fingerprinting methods, DGGE and SSCP.

Effects of hybrid and bacterial inoculation on fermentation quality and fatty acid profile of barley silage.

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Kim, Dong Hyeon; Amanullah, Sadar M; Lee, Hyuk Jun; Joo, Young Ho; Han, Ouk Kyu; Adesogan, Adegbola T; Kim, Sam Churl

2018-01-01

This study estimated the effects of hybrid and bacterial inoculant on fermentation quality and fatty acid profile of barley silages. Yuyeon (Silkless) and Youngyang (Silking) barley hybrids were harvested at 24.9 and 27.1% dry matter, respectively, and chopped to 10 cm lengths. Each hybrid was treated with or without an inoculant (2 × 10 4  colony-forming units/g of Lactobacillus plantarum). A total of 48 silos were prepared in an experiment with a 2 × 2 (hybrid × inoculant) treatment arrangement with four replications and three ensiling durations (2, 7 and 100 days). After 100 days of ensiling, Yuyeon silage had higher (P hybrids and increased (P hybrid might have better potential benefits on animal performances due to its smooth awn and silkless nature, and higher in vitro dry matter digestibility. Its higher C18:3n-3 would be better for improving fatty acid profile of meat or milk than Youngyang hybrid. © 2017 Japanese Society of Animal Science.

Isolation and characterization of two new methanesulfonic acid-degrading bacterial isolates from a Portuguese soil sample.

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De Marco, P; Murrell, J C; Bordalo, A A; Moradas-Ferreira, P

2000-02-01

Two novel bacterial strains that can utilize methanesulfonic acid as a source of carbon and energy were isolated from a soil sample collected in northern Portugal. Morphological, physiological, biochemical and molecular biological characterization of the two isolates indicate that strain P1 is a pink-pigmented facultative methylotroph belonging to the genus Methylobacterium, while strain P2 is a restricted methylotroph belonging to the genus Hyphomicrobium. Both strains are strictly aerobic, degrade methanesulfonate, and release small quantities of sulfite into the medium. Growth on methanesulfonate induces a specific polypeptide profile in each strain. This, together with the positive hybridization to a DNA probe that carries the msm genes of Methylosulfonomonas methylovora strain M2, strongly endorses the contention that a methanesulfonic acid monooxygenase related to that found in the previously known methanesulfonate-utilizing bacteria is present in strains P1 and P2. The isolation of bacteria containing conserved msm genes from diverse environments and geographical locations supports the hypothesis that a common enzyme may be globally responsible for the oxidation of methanesulfonate by natural methylotrophic communities.

Effect of Dietary Protein Levels on Composition of Odorous Compounds and Bacterial Ecology in Pig Manure

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Sungback Cho

2015-09-01

Full Text Available This study was performed to investigate the effect of different levels of dietary crude protein (CP on composition of odorous compounds and bacterial communities in pig manure. A total of 48 male pigs (average initial body weight 45 kg fed diets containing three levels of dietary CP (20%, 17.5%, and 15% and their slurry samples were collected from the pits under the floor every week for one month. Changes in composition of odorous compounds and bacterial communities were analyzed by gas chromatography and 454 FLX titanium pyrosequencing systems, respectively. Levels of phenols, indoles, short chain fatty acid and branched chain fatty acid were lowest (p<0.05 in CP 15% group among three CP levels. Relative abundance of Bacteroidetes phylum and bacterial genera including Leuconostoc, Bacillus, Atopostipes, Peptonphilus, Ruminococcaceae_uc, Bacteroides, and Pseudomonas was lower (p<0.05 in CP 15% than in CP 20% group. There was a positive correlation (p<0.05 between odorous compounds and bacterial genera: phenol, indole, iso-butyric acid, and iso-valeric acid with Atopostipes, p-cresol and skatole with Bacteroides, acetic acid and butyric acid with AM982595_g of Porphyromonadaceae family, and propionic acid with Tissierella. Taken together, administration of 15% CP showed less production of odorous compounds than 20% CP group and this result might be associated with the changes in bacterial communities especially whose roles in protein metabolism.

Bacterial populations and environmental factors controlling cellulose degradation in an acidic Sphagnum peat.

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Pankratov, Timofey A; Ivanova, Anastasia O; Dedysh, Svetlana N; Liesack, Werner

2011-07-01

Northern peatlands represent a major global carbon store harbouring approximately one-third of the global reserves of soil organic carbon. A large proportion of these peatlands consists of acidic Sphagnum-dominated ombrotrophic bogs, which are characterized by extremely low rates of plant debris decomposition. The degradation of cellulose, the major component of Sphagnum-derived litter, was monitored in long-term incubation experiments with acidic (pH 4.0) peat extracts. This process was almost undetectable at 10°C and occurred at low rates at 20°C, while it was significantly accelerated at both temperature regimes by the addition of available nitrogen. Cellulose breakdown was only partially inhibited in the presence of cycloheximide, suggesting that bacteria participated in this process. We aimed to identify these bacteria by a combination of molecular and cultivation approaches and to determine the factors that limit their activity in situ. The indigenous bacterial community in peat was dominated by Alphaproteobacteria and Acidobacteria. The addition of cellulose induced a clear shift in the community structure towards an increase in the relative abundance of the Bacteroidetes. Increasing temperature and nitrogen availability resulted in a selective development of bacteria phylogenetically related to Cytophaga hutchinsonii (94-95% 16S rRNA gene sequence similarity), which densely colonized microfibrils of cellulose. Among isolates obtained from this community only some subdivision 1 Acidobacteria were capable of degrading cellulose, albeit at a very slow rate. These Acidobacteria represent indigenous cellulolytic members of the microbial community in acidic peat and are easily out-competed by Cytophaga-like bacteria under conditions of increased nitrogen availability. Members of the phylum Firmicutes, known to be key players in cellulose degradation in neutral habitats, were not detected in the cellulolytic community enriched at low pH. © 2011 Society for

Supplementing Blends of Sugars, Amino Acids, and Secondary Metabolites to the Diet of Termites (Reticulitermes flavipes) Drive Distinct Gut Bacterial Communities.

Science.gov (United States)

Huang, Xing-Feng; Chaparro, Jacqueline M; Reardon, Kenneth F; Judd, Timothy M; Vivanco, Jorge M

2016-10-01

Although it is well known that diet is one of the major modulators of the gut microbiome, how the major components of diet shape the gut microbial community is not well understood. Here, we developed a simple system that allows the investigation of the impact of given compounds as supplements of the diet on the termite gut microbiome. The 16S rRNA pyrosequencing analysis revealed that feeding termites different blends of sugars and amino acids did not majorly impact gut community composition; however, ingestion of blends of secondary metabolites caused shifts in gut bacterial community composition. The supplementation of sugars and amino acids reduced the richness significantly, and sugars alone increased the evenness of the gut bacterial community significantly. Secondary metabolites created the most dramatic effects on the microbial community, potentially overriding the effect of other types of compounds. Furthermore, some microbial groups were stimulated specifically by particular groups of compounds. For instance, termites fed with secondary metabolites contained more Firmicutes and Spirochaetes compared to the other treatments. In conclusion, our results suggest that the termite (Reticulitermes flavipes) can be used as a simple and effective system to test the effects of particular chemical compounds in modulating the gut microbiome.

Bacterial and archaeal diversities in Yunnan and Tibetan hot springs, China.

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Song, Zhao-Qi; Wang, Feng-Ping; Zhi, Xiao-Yang; Chen, Jin-Quan; Zhou, En-Min; Liang, Feng; Xiao, Xiang; Tang, Shu-Kun; Jiang, Hong-Chen; Zhang, Chuanlun L; Dong, Hailiang; Li, Wen-Jun

2013-04-01

Thousands of hot springs are located in the north-eastern part of the Yunnan-Tibet geothermal zone, which is one of the most active geothermal areas in the world. However, a comprehensive and detailed understanding of microbial diversity in these hot springs is still lacking. In this study, bacterial and archaeal diversities were investigated in 16 hot springs (pH 3.2-8.6; temperature 47-96°C) in Yunnan Province and Tibet, China by using a barcoded 16S rRNA gene-pyrosequencing approach. Aquificae, Proteobacteria, Firmicutes, Deinococcus-Thermus and Bacteroidetes comprised the large portion of the bacterial communities in acidic hot springs. Non-acidic hot springs harboured more and variable bacterial phyla than acidic springs. Desulfurococcales and unclassified Crenarchaeota were the dominated groups in archaeal populations from most of the non-acidic hot springs; whereas, the archaeal community structure in acidic hot springs was simpler and characterized by Sulfolobales and Thermoplasmata. The phylogenetic analyses showed that Aquificae and Crenarchaeota were predominant in the investigated springs and possessed many phylogenetic lineages that have never been detected in other hot springs in the world. Thus findings from this study significantly improve our understanding of microbial diversity in terrestrial hot springs. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Carbon nanomaterials alter plant physiology and soil bacterial community composition in a rice-soil-bacterial ecosystem.

Science.gov (United States)

Hao, Yi; Ma, Chuanxin; Zhang, Zetian; Song, Youhong; Cao, Weidong; Guo, Jing; Zhou, Guopeng; Rui, Yukui; Liu, Liming; Xing, Baoshan

2018-01-01

The aim of this study was to compare the toxicity effects of carbon nanomaterials (CNMs), namely fullerene (C 60 ), reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs), on a mini-ecosystem of rice grown in a loamy potted soil. We measured plant physiological and biochemical parameters and examined bacterial community composition in the CNMs-treated plant-soil system. After 30 days of exposure, all the three CNMs negatively affected the shoot height and root length of rice, significantly decreased root cortical cells diameter and resulted in shrinkage and deformation of cells, regardless of exposure doses (50 or 500 mg/kg). Additionally, at the high exposure dose of CNM, the concentrations of four phytohormones, including auxin, indoleacetic acid, brassinosteroid and gibberellin acid 4 in rice roots significantly increased as compared to the control. At the high exposure dose of MWCNTs and C 60 , activities of the antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD) in roots increased significantly. High-throughput sequencing showed that three typical CNMs had little effect on shifting the predominant soil bacterial species, but the presence of CNMs significantly altered the composition of the bacterial community. Our results indicate that different CNMs indeed resulted in environmental toxicity to rice and soil bacterial community in the rhizosphere and suggest that CNMs themselves and their incorporated products should be reasonably used to control their release/discharge into the environment to prevent their toxic effects on living organisms and the potential risks to food safety. Copyright © 2017 Elsevier Ltd. All rights reserved.

The microbiota and microbiome in aging: potential implications in health and age-related diseases.

Science.gov (United States)

Zapata, Heidi J; Quagliarello, Vincent J

2015-04-01

Advances in bacterial deoxyribonucleic acid sequencing allow for characterization of the human commensal bacterial community (microbiota) and its corresponding genome (microbiome). Surveys of healthy adults reveal that a signature composite of bacteria characterizes each unique body habitat (e.g., gut, skin, oral cavity, vagina). A myriad of clinical changes, including a basal proinflammatory state (inflamm-aging), that directly interface with the microbiota of older adults and enhance susceptibility to disease accompany aging. Studies in older adults demonstrate that the gut microbiota correlates with diet, location of residence (e.g., community dwelling, long-term care settings), and basal level of inflammation. Links exist between the microbiota and a variety of clinical problems plaguing older adults, including physical frailty, Clostridium difficile colitis, vulvovaginal atrophy, colorectal carcinoma, and atherosclerotic disease. Manipulation of the microbiota and microbiome of older adults holds promise as an innovative strategy to influence the development of comorbidities associated with aging. © 2015, Copyright the Authors Journal compilation © 2015, The American Geriatrics Society.

Soil Acidification Aggravates the Occurrence of Bacterial Wilt in South China

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Chen Xu

2017-04-01

Full Text Available Soil acidification is a major problem in modern agricultural systems and is an important factor affecting the soil microbial community and soil health. However, little is known about the effect of soil acidification on soil-borne plant diseases. We performed a 4-year investigation in South China to evaluate the correlation between soil acidification and the occurrence of bacterial wilt. The results showed that the average soil pH in fields infected by bacterial wilt disease was much lower than that in non-disease fields. Moreover, the proportion of infected soils with pH lower than 5.5 was much higher than that of non-infected soils, and this phenomenon became more obvious as the area of bacterial wilt disease increased at soil pH lower than 5.5 from 2011 to 2014. Then, in a field pot experiment, bacterial wilt disease developed more quickly and severely in acidic conditions of pH 4.5, 5.0, and 5.5. These results indicate that soil acidification can cause the outbreak of bacterial wilt disease. Further experiments showed that acidic conditions (pH 4.5–5.5 favored the growth of the pathogen Ralstonia solanacearum but suppressed the growth and antagonistic activity of antagonistic bacteria of Pseudomonas fluorescens and Bacillus cereus. Moreover, acidic conditions of pH 5.5 were conducive to the expression of the virulence genes PopA, PrhA, and SolR but restrained resistance gene expression in tobacco. Finally, application of wood ash and lime as soil pH amendments improved soil pH and reduced the occurrence of bacterial wilt. Together, these findings improve our understanding of the correlation between soil acidification and soil-borne plant diseases and also suggest that regulation of soil acidification is the precondition and foundation of controlling bacterial wilt.

Modification and restriction of T-even bacteriophages. In vitro degradation of deoxyribonucleic acid containing 5-hydroxymethylctosine.

Science.gov (United States)

Fleischman, R A; Cambell, J L; Richardson, C C

1976-03-25

Using the single-stranded circular DNA of bacteriophage fd as template, double-stranded circular DNA has been prepared in vitro with either 5-hydroxymethylcytosine ([hmdC]DNA) or cytosine ([dC]DNA) in the product strand. Extracts prepared from Escherichia coli cells restrictive to T-even phage containing nonglucosylated DNA degrade [hmdC]DNA to acid-soluble material in vitro, but do not degrade [dC]dna. In contrast, extracts prepared from E. coli K12 rglA- rglB-, a strain permissive to T-even phage containing nonglucosylated DNA, do not degrade [hmdC]DNA or [dC]DNA. In addition, glucosylation of the [hmdC]DNA renders it resistant to degradation by extracts from restrictive strains. The conversion of [hmdC]DNA to acid-soluble material in vitro consists of an HmCyt-specific endonucleolytic cleavage requiring the presence of the RglB gene product to form a linear molecule, followed by a non-HmCyt-specific hydrolysis of the linear DNA to acid-soluble fragments, catalyzed in part by exonuclease V. The RglB protein present in extracts of E. coli K12 rglA- rglB+ has been purified 200-fold by complementation with extracts from E. coli K12 rglA- rglB-. The purified RglB protein does not contain detectable HmCyt-specific endonuclease or exonuclease activity. In vitro endonucleolytic cleavage of [hmdC]DNA thus requires additional factors present in cell extracts.

The experimental study of bacterial leaching at condition of different ore's diameter

International Nuclear Information System (INIS)

Liu Jinhui; Li Lin; Liu Yajie

2006-01-01

This papper compared the effect of leaching rate of uranium and the adaptability of bacteria with the condition of different ore's diameter (2-5 mm, 5-10 mm), which use the way of inleakage-leaching. The experiment use the way that firstly acid leaching, and then 2 bacterial leaching. As a reasult that the total leaching-rate of minute diameter ore are always high than the big diameter one. But for the quantum of consumed acid its just a opposition. During bacterial leaching the adaptability of bacteria in big diameter ore are high than in the minute one. So this experiment may offer a bases for a latter industry experiment which use big diameter ore's bacterial leaching. (authors)

Thin-layer chromatographic technique for rapid detection of bacterial phospholipases.

Science.gov (United States)

Legakis, N J; Papavassiliou, J

1975-11-01

Silica gel thin-layer chromatography was employed to detect lecithinase activity induced from bacterial resting cell preparations induced from bacterial resting cell preparations incubated at 37 C for 4 h in the presence of purified egg yolk lecithin. Bacillus subtilis, Bacillus cereus, Serratia marcescens, and Pseudomonas aeruginosa hydrolyzed lecithin with the formation of free fatty acids as the sole lipid-soluble product. In none of the Escherichia coli and Citrobacter freundii strains tested could lecithinase activity be detected. Four among eight strains of Enterobacter aerogenes and one among 12 strains of Proteus tested produced negligible amounts of free fatty acid.

PCR-based detection of bacterial DNA after antimicrobial treatment is indicative of persistent, viable bacteria in the chinchilla model of otitis media.

Science.gov (United States)

Post, J C; Aul, J J; White, G J; Wadowsky, R M; Zavoral, T; Tabari, R; Kerber, B; Doyle, W J; Ehrlich, G D

1996-01-01

Bacterial deoxyribonucleic acid (DNA) has been previously detected by polymerase chain reactions (PCR) in a significant percentage of culturally-sterile pediatric middle-ear effusions. The current study was designed to determine whether this represents the existence of viable bacteria or the persistence of residual DNA in the middle-ear cleft. The middle-ear cavities of two sets of chinchillas were inoculated with either: 1) 100 colony-forming units (CFU) of live Haemophilus influenzae, 2.2 x 10(6) CFU of pasteurized Moraxella catarrhalis, and 1000 ng of DNA (>10(8) genomic equivalents) from Streptococcus pneumoniae; or 2) 100 CFU of live S pneumoniae, 2.2 x 10(6) CFU of pasteurized M catarrhalis and 1000 ng of purified DNA from H influenzae. Animals were treated with ampicillin for 5 days beginning on day 3. A single-point longitudinal study design was used for sampling to eliminate the possibility of contamination. No DNA was detectable from the heat-killed bacteria or the purified DNA after day 3. However, DNA from the live bacteria persisted through day 21, even though all specimens were culture-negative following the initiation of antimicrobial therapy. These findings indicate that purified DNA and DNA from intact but nonviable bacteria do not persist in the middle-ear cleft in the presence of an effusion, even following high copy inoculation. In contrast, antibiotic-treated bacteria persist in some viable state for weeks as evidenced by the differential ability of the PCR-based assay systems to detect the live bacteria, but not detect the heat-killed organisms.

Structural aspects of catalytic mechanisms of endonucleases and their binding to nucleic acids

Energy Technology Data Exchange (ETDEWEB)

Zhukhlistova, N. E.; Balaev, V. V.; Lyashenko, A. V.; Lashkov, A. A., E-mail: alashkov83@gmail.com [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2012-05-15

Endonucleases (EC 3.1) are enzymes of the hydrolase class that catalyze the hydrolytic cleavage of deoxyribonucleic and ribonucleic acids at any region of the polynucleotide chain. Endonucleases are widely used both in biotechnological processes and in veterinary medicine as antiviral agents. Medical applications of endonucleases in human cancer therapy hold promise. The results of X-ray diffraction studies of the spatial organization of endonucleases and their complexes and the mechanism of their action are analyzed and generalized. An analysis of the structural studies of this class of enzymes showed that the specific binding of enzymes to nucleic acids is characterized by interactions with nitrogen bases and the nucleotide backbone, whereas the nonspecific binding of enzymes is generally characterized by interactions only with the nucleic-acid backbone. It should be taken into account that the specificity can be modulated by metal ions and certain low-molecular-weight organic compounds. To test the hypotheses about specific and nonspecific nucleic-acid-binding proteins, it is necessary to perform additional studies of atomic-resolution three-dimensional structures of enzyme-nucleic-acid complexes by methods of structural biology.

Self-assembled monolayer based electrochemical nucleic acid sensor for Vibrio cholerae detection

International Nuclear Information System (INIS)

Patel, Manoj K; Solanki, Pratima R; Agrawal, Ved V; Khandelwal, Sachin; Ansari, S G; Malhotra, B D

2012-01-01

Nucleic acid sensor has been fabricated by immobilization of thiolated (5' end) single stranded deoxyribonucleic acid probe (ssDNA-SH) onto gold (Au) coated glass electrode for Vibriocholerae detection. This ssDNA-SH/Au bioelectrode characterized using atomic force microscopy (AFM),Fourier transforms infrared spectroscopy (FT-IR) and electrochemical technique, has been used for hybridization detection of genomic DNA (dsDNA/Au). This ssDNA-SH/Au bioelectrode can specifically detect up to 100- 500 ng/μL genomic DNA of Vibriocholeare within 60 s of hybridization time at 25°C by cyclic voltammetry (CV) using methylene blue (MB) as electro-active DNA hybridization indicator. The value of sensitivity of the dsDNA/Au electrode has been determined as 0.027μA/ng cm −2 with regression coefficient as 0.978. This DNA bioelectrode is stable for about 4 months when stored at 4°C.

Protocol optimization for deoxyribonucleic acid (DNA) extraction ...

African Journals Online (AJOL)

MUNAWAR ROOMI

2013-12-18

Dec 18, 2013 ... research institutes, such as National Agricultural Research Centre. (NARC) .... and was experienced on soybean, chickpea seeds and wheat. When high ... suitable for molecular marker and transgenic analysis. Afr. J.

Protocol optimization for deoxyribonucleic acid (DNA) extraction ...

African Journals Online (AJOL)

Arachis hypogaea L.) is particularly problematic due to the presence of phenolic compounds and polysaccharides. Inconsistencies in extraction results can be attributed to the age and growth stages of the plant material analyzed. Mature leaves ...

Antimicrobial Nanoparticle for the Treatment of Bacterial Infection

Science.gov (United States)

Pornpattananangkul, Dissaya

Liposomes are spherical lipid vesicles with bilayered membrane structure, which have been recognized as one of the most widely used carriers for delivering a myriad of pharmaceuticals. Liposomes can carry both hydrophilic and hydrophobic agents with high efficiency and protect them from undesired effects of external conditions. However, the applications of liposomes are usually limited by their instability during storage. They are inclined to fuse with one another immediately after preparation, resulting in undesired mixing, increase in size, and payload loss. To overcome this limitation, this dissertation will focus on the technology to stabilize liposomes during storage and destabilize at specific conditions in order to allow controllable therapeutic release, as well as demonstrate their application to treat one of the bacterial infection diseases, acne vulgaris. The first area of this research is stimuli-responsive liposomes development, where the liposomes are stabilized by introducing gold nanoparticles to adsorb to their surface. As a result, the liposomes are prevented from fusing with one another and undesirable payload release during storage or physiological environments. Moreover, therapeutic is controllably released depending on environment conditions, such as acidic pH and bacterial virulence factor. In case of acid-responsive liposomes, the bound gold nanoparticles can effectively prevent liposomes from fusing with one another at neutral pH value, while at acidic environment (e.g. pHhuman skin are typically acidic. Demonstrated by fluorescent and antimicrobial experiments, the bound gold nanoparticles effectively prevent LipoLA from fusing with one another at neutral pH value. However, at acidic condition, the gold particles detatch from LipoLA surface, allowing the fusion with P.acnes membrane and lauric acid delivery, resulting in a complete killing effect. The stimuli-responsive liposomes presented here provide a new, safe, and effective approach to

Present and future etiological treatment of bacterial pneumonia 3. The antibacterial drugs under development

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A.A. Abaturov

2017-08-01

Full Text Available The rapid spread of antibiotic-resistant bacterial strains necessitates the development of new antibacterial agents and a review of the guidelines for etiological treatment of bacterial infections, including pneumonia. Currently, new antibacterial agents are being developed that disrupt the biosynthesis of peptidoglycan, teichoic and lipoteichoic acids, and also block the attachment of virulent factors to the bacterial wall. New molecules of old classes of antibiotics and representatives of new classes of antibiotics with their targets (lipid II and III, teichoic and lipoteichoic acids, alanine racemase, and sortase A will become practical tools in clinical practice in the very near future. The goals and mechanisms of action of new antibacterial compounds predetermine their clinical prospects in future strategies for the treatment of infectious bacterial diseases.

A locked nucleic acid (LNA-based real-time PCR assay for the rapid detection of multiple bacterial antibiotic resistance genes directly from positive blood culture.

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Lingxiang Zhu

Full Text Available Bacterial strains resistant to various antibiotic drugs are frequently encountered in clinical infections, and the rapid identification of drug-resistant strains is highly essential for clinical treatment. We developed a locked nucleic acid (LNA-based quantitative real-time PCR (LNA-qPCR method for the rapid detection of 13 antibiotic resistance genes and successfully used it to distinguish drug-resistant bacterial strains from positive blood culture samples. A sequence-specific primer-probe set was designed, and the specificity of the assays was assessed using 27 ATCC bacterial strains and 77 negative blood culture samples. No cross-reaction was identified among bacterial strains and in negative samples, indicating 100% specificity. The sensitivity of the assays was determined by spiking each bacterial strain into negative blood samples, and the detection limit was 1-10 colony forming units (CFU per reaction. The LNA-qPCR assays were first applied to 72 clinical bacterial isolates for the identification of known drug resistance genes, and the results were verified by the direct sequencing of PCR products. Finally, the LNA-qPCR assays were used for the detection in 47 positive blood culture samples, 19 of which (40.4% were positive for antibiotic resistance genes, showing 91.5% consistency with phenotypic susceptibility results. In conclusion, LNA-qPCR is a reliable method for the rapid detection of bacterial antibiotic resistance genes and can be used as a supplement to phenotypic susceptibility testing for the early detection of antimicrobial resistance to allow the selection of appropriate antimicrobial treatment and to prevent the spread of resistant isolates.

The role indigenous bacterial isolates for bioremediation agent in the uranium contaminated aquatic environment

International Nuclear Information System (INIS)

Mochd Yazid

2014-01-01

A Research on the role of indigenous bacterial isolates for bio-remediation agent of the uranium contaminated in the aquatic environment has been conducted. The objective of the research is to study the role of Pseudomonas sp and Bacillus sp. have been isolated from low level uranium waste for bioremediation agent in their environment, such as the determination of efficiency of the uranium binding compared by the non indigenous bacterial, location of these binding and the influences of added acethyl acid stimulant. The uranium reduction studied was measured by weighting bacterial biomass and uranium concentration was measured by spectrophotometer. The acethyl acid stimulant addition has been done with the variation of concentration and volume. The efficiency of the uranium reduction by indigenous bacterial isolate such as Pseudomonas sp were 84.99 % and Bacillus sp were 52.70 %, so the reduction efficiency by non indigenous bacterial such as Pseudomonas aerogenes were 78.47 % and Bacillus subtilis were 45.22 % for 54 hours incubation time. The result of this research can be concluded that Pseudomonas sp and Bacillus sp. Indigenous bacterial have been isolates from the liquid uranium waste can contributed in bioremediation agent for uranium radionuclide in the environment for 60 ppm concentration with reduction efficiency 52.70 %-84.99 %, that is higher non indigenous bacterial for 54 hours incubation time, the stimulant addition of acethyl acid, the efficiency can be increased up to 99.8 %. (author)

The relationships between odd- and branched-chain fatty acids to ruminal fermentation parameters and bacterial populations with different dietary ratios of forage and concentrate.

Science.gov (United States)

Zhang, Y; Liu, K; Hao, X; Xin, H

2017-12-01

The objectives of this study were to investigate the effect of different dietary ratios of forage and concentrate (F:C) on ruminal odd- and branched-chain fatty acids (OBCFAs) contents and to evaluate the relationships between OBCFA and ruminal fermentation parameters as well as bacterial populations tested by real-time PCR technique. The experimental design was a 3 × 3 Latin square. Three rumen-fistulated dry Holstein cows were fed three rations with different dietary F:C ratios (F:C; 30:70, 50:50 and 70:30). The rumen samples were collected every two hours (0600, 0800, 1000, 1200, 1400, 1600, 1800, 2000, 2200, 2400, 0200 and 0400 h) over three consecutive days in each sampling period. The results showed that rumen OBCFA profiles are significantly (p ruminal OBCFAs had strong relationships with ruminal fermentation parameters and bacterial populations. In particular, the iso-fatty acids had potential power to predict butyrate and isoacids metabolized in the rumen, whereas the fatty acids with 17 carbon atoms correlated with ruminal NH 3 -N content. The OBCFA contents have different relationships with fibrolytic and starch bacteria in the rumen. C17:0 and its isomers might be used to predict populations of fibrolytic bacteria. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

Phytoplankton-Associated Bacterial Community Composition and Succession during Toxic Diatom Bloom and Non-Bloom Events.

Science.gov (United States)

Sison-Mangus, Marilou P; Jiang, Sunny; Kudela, Raphael M; Mehic, Sanjin

2016-01-01

Pseudo-nitzschia blooms often occur in coastal and open ocean environments, sometimes leading to the production of the neurotoxin domoic acid that can cause severe negative impacts to higher trophic levels. Increasing evidence suggests a close relationship between phytoplankton bloom and bacterial assemblages, however, the microbial composition and succession during a bloom process is unknown. Here, we investigate the bacterial assemblages before, during and after toxic and non-toxic Pseudo-nitzschia blooms to determine the patterns of bacterial succession in a natural bloom setting. Opportunistic sampling of bacterial community profiles were determined weekly at Santa Cruz Municipal Wharf by 454 pyrosequencing and analyzed together with domoic acid levels, phytoplankton community and biomass, nutrients and temperature. We asked if the bacterial communities are similar between bloom and non-bloom events and if domoic acid or the presence of toxic algal species acts as a driving force that can significantly structure phytoplankton-associated bacterial communities. We found that bacterial diversity generally increases when Pseudo-nitzschia numbers decline. Furthermore, bacterial diversity is higher when the low-DA producing P. fraudulenta dominates the algal bloom while bacterial diversity is lower when high-DA producing P. australis dominates the algal bloom, suggesting that the presence of algal toxin can structure bacterial community. We also found bloom-related succession patterns among associated bacterial groups; Gamma-proteobacteria, were dominant during low toxic P. fraudulenta blooms comprising mostly of Vibrio spp., which increased in relative abundance (6-65%) as the bloom progresses. On the other hand, Firmicutes bacteria comprising mostly of Planococcus spp. (12-86%) dominate during high toxic P. australis blooms, with the bacterial assemblage showing the same bloom-related successional patterns in three independent bloom events. Other environmental

Phytoplankton-associated bacterial community composition and succession during toxic diatom bloom and non-bloom events

Directory of Open Access Journals (Sweden)

Marilou P. Sison-Mangus

2016-09-01

Full Text Available Pseudo-nitzschia blooms often occur in coastal and open ocean environments, sometimes leading to the production of the neurotoxin domoic acid that can cause severe negative impacts to higher trophic levels. Increasing evidence suggests a close relationship between phytoplankton bloom and bacterial assemblages, however, the microbial composition and succession during a bloom process is unknown. Here, we investigate the bacterial assemblages before, during and after toxic and non-toxic Pseudo-nitzschia blooms to determine the patterns of bacterial succession in a natural bloom setting. Opportunistic sampling of bacterial community profiles were determined weekly at Santa Cruz Municipal Wharf by 454 pyrosequencing and analyzed together with domoic acid levels, phytoplankton community and biomass, nutrients and temperature. We asked if the bacterial communities are similar between bloom and non-bloom events and if domoic acid or the presence of toxic algal species acts as a driving force that can significantly structure phytoplankton-associated bacterial communities. We found that bacterial diversity generally increases when Pseudo-nitzschia numbers decline. Furthermore, bacterial diversity is higher when the low-DA producing P. fraudulenta dominates the algal bloom while bacterial diversity is lower when high-DA producing P. australis dominates the algal bloom, suggesting that the presence of algal toxin can structure bacterial community. We also found bloom-related succession patterns among associated bacterial groups; Gamma-proteobacteria, were dominant during low toxic P. fraudulenta blooms comprising mostly of Vibrio spp., which increased in relative abundance (6%-65% as the bloom progresses. On the other hand, Firmicutes bacteria comprising mostly of Planococcus spp. (12%- 86% dominate during high toxic P. australis blooms, with the bacterial assemblage showing the same bloom-related successional patterns in 3 independent bloom events. Other

Food irradiation and bacterial toxins

International Nuclear Information System (INIS)

Tranter, H.S.; Modi, N.K.; Hambleton, P.; Melling, J.; Rose, S.; Stringer, M.F.

1987-01-01

The authors' findings indicate that irradiation confers no advantage over heat processing in respect of bacterial toxins (clostridium botulinum, neurotoxin A and staphylococcal enterotoxin A). It follows that irradiation at doses less than the ACINF recommended upper limit of 10 kGy could not be used to improve the ambient temperature shelf life on non-acid foods. (author)

Cellular reprogramming by gram-positive bacterial components: a review.

LENUS (Irish Health Repository)

Buckley, Julliette M

2012-02-03

LPS tolerance has been the focus of extensive scientific and clinical research over the last several decades in an attempt to elucidate the sequence of changes that occur at a molecular level in tolerized cells. Tolerance to components of gram-positive bacterial cell walls such as bacterial lipoprotein and lipoteichoic acid is a much lesser studied, although equally important, phenomenon. This review will focus on cellular reprogramming by gram-positive bacterial components and examines the alterations in cell surface receptor expression, changes in intracellular signaling, gene expression and cytokine production, and the phenomenon of cross-tolerance.

Polypyrrole-polyvinyl sulphonate film based disposable nucleic acid biosensor

Energy Technology Data Exchange (ETDEWEB)

Prabhakar, Nirmal [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Centre for Biomedical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Arora, Kavita [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Singh, Surinder P. [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Pandey, Manoj K. [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Singh, Harpal [Centre for Biomedical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Malhotra, Bansi D. [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India)]. E-mail: bansi.malhotra@gmail.com

2007-04-18

Double stranded calf thymus deoxyribonucleic acid entrapped polypyrrole-polyvinyl sulphonate (dsCT-DNA-PPy-PVS) films fabricated onto indium-tin-oxide (ITO) coated glass plates have been used to detect organophosphates such as chlorpyrifos and malathion. These disposable dsCT-DNA-PPy-PVS/ITO bioelectrodes have been characterized using cyclic voltammetry, Fourier-transform-infra-red (FTIR) spectroscopy and atomic force microscopy (AFM), respectively. These biosensing electrodes have a response time of 30 s, are stable for about 5 months when stored in desiccated conditions at 25 deg. C and can be used to amperometrically detect chlorpyrifos (0.0016-0.025 ppm) and malathion (0.17-5.0), respectively. The additive effect of these pesticides on the amperometric response of the disposable dsCT-DNA-PPy-PVS/ITO bioelectrodes has also been investigated.

Bacterial decolorization and detoxification of black liquor from rayon grade pulp manufacturing paper industry and detection of their metabolic products.

Science.gov (United States)

Chandra, Ram; Abhishek, Amar; Sankhwar, Monica

2011-06-01

This study deals with the decolorization of black liquor (BL) by isolated potential bacterial consortium comprising Serratia marcescens (GU193982), Citrobacter sp. (HQ873619) and Klebsiella pneumoniae (GU193983). The decolorization of BL was studied by using the different nutritional as well as environmental parameters. In this study, result revealed that the ligninolytic activities were found to be growth associated and the developed bacterial consortium was efficient for the reduction of COD, BOD and color up to 83%, 74% and 85%, respectively. The HPLC analysis of degraded samples of BL has shown the reduction in peak area compared to control. Further, the GC-MS analysis showed that, most of the compounds detected in control were diminished after bacterial treatment while, formic acid hydrazide, 4-cyclohexane-1,2-dicarboxylic acid, carbamic acid, 1,2-benzenedicarboxylic acid and erythropentanoic acid were found as new metabolites. Further, the seed germination test using Phaseolus aureus has supported the detoxification of bacterial decolorized BL. Copyright © 2011 Elsevier Ltd. All rights reserved.

First improvements in the detection and quantification of label-free nucleic acids by laser-induced breakdown spectroscopy: Application to the deoxyribonucleic acid micro-array technology

International Nuclear Information System (INIS)

Le Meur, Julien; Menut, Denis; Wodling, Pascal; Salmon, Laurent; Thro, Pierre-Yves; Chevillard, Sylvie; Ugolin, Nicolas

2008-01-01

The accurate quantification of nucleic acids is essential in many fields of modern biology and industry, and in some cases requires the use of fluorescence labeling. Yet, in addition to standardization problems and quantification reproducibility, labeling can modify the physicochemical properties of molecules or affect their stability. To address these limitations, we have developed a novel method to detect and quantify label-free nucleic acids. This method is based on stoichiometric proportioning of phosphorus in the nucleic acid skeleton, using laser-induced breakdown spectroscopy, and a specific statistical analysis, which indicates the error probability for each measurement. The results obtained appear to be quantitative, with a limit of detection of 10 5 nucleotides/μm 2 (i.e. 2 x 10 13 phosphorus atoms/cm 2 ). Initial micro-array analysis has given very encouraging results, which point to new ways of quantifying hybridized nucleic acids. This is essential when comparing molecules of different sequences, which is presently very difficult with fluorescence labeling

First improvements in the detection and quantification of label-free nucleic acids by laser-induced breakdown spectroscopy: Application to the deoxyribonucleic acid micro-array technology

Energy Technology Data Exchange (ETDEWEB)

Le Meur, Julien [Laboratoire de Cancerologie Experimentale, Commissariat a l' Energie Atomique de Fontenay-aux-Roses, Direction des Sciences du Vivant, Departement de Radiobiologie et Radiopathologie, Fontenay-aux-Roses (France); Menut, Denis [Laboratoire de Reactivite des Surfaces et des Interfaces, Commissariat a l' Energie Atomique de Saclay, Direction de l' Energie Nucleaire, Departement de Physico-Chimie, Gif sur Yvette (France); Wodling, Pascal [Laboratoire d' Interaction Laser-Matiere, Commissariat a l' Energie Atomique de Saclay, Direction de l' Energie Nucleaire, Departement de Physico-Chimie, Gif sur Yvette (France); Salmon, Laurent [Laboratoire de Reactivite des Surfaces et des Interfaces, Commissariat a l' Energie Atomique de Saclay, Direction de l' Energie Nucleaire, Departement de Physico-Chimie, Gif sur Yvette (France); Thro, Pierre-Yves [Laboratoire d' Interaction Laser-Matiere, Commissariat a l' Energie Atomique de Saclay, Direction de l' Energie Nucleaire, Departement de Physico-Chimie, Gif sur Yvette (France); Chevillard, Sylvie [Laboratoire de Cancerologie Experimentale, Commissariat a l' Energie Atomique de Fontenay-aux-Roses, Direction des Sciences du Vivant, Departement de Radiobiologie et Radiopathologie, Fontenay-aux-Roses (France); Ugolin, Nicolas [Laboratoire de Cancerologie Experimentale, Commissariat a l' Energie Atomique de Fontenay-aux-Roses, Direction des Sciences du Vivant, Departement de Radiobiologie et Radiopathologie, Fontenay-aux-Roses (France)], E-mail: nugolin@cea.fr

2008-04-15

The accurate quantification of nucleic acids is essential in many fields of modern biology and industry, and in some cases requires the use of fluorescence labeling. Yet, in addition to standardization problems and quantification reproducibility, labeling can modify the physicochemical properties of molecules or affect their stability. To address these limitations, we have developed a novel method to detect and quantify label-free nucleic acids. This method is based on stoichiometric proportioning of phosphorus in the nucleic acid skeleton, using laser-induced breakdown spectroscopy, and a specific statistical analysis, which indicates the error probability for each measurement. The results obtained appear to be quantitative, with a limit of detection of 10{sup 5} nucleotides/{mu}m{sup 2} (i.e. 2 x 10{sup 13} phosphorus atoms/cm{sup 2}). Initial micro-array analysis has given very encouraging results, which point to new ways of quantifying hybridized nucleic acids. This is essential when comparing molecules of different sequences, which is presently very difficult with fluorescence labeling.

Effects of humic acid on the interactions between zinc oxide nanoparticles and bacterial biofilms.

Science.gov (United States)

Ouyang, Kai; Yu, Xiao-Ying; Zhu, Yunlin; Gao, Chunhui; Huang, Qiaoyun; Cai, Peng

2017-12-01

The effects of humic acid (HA) on interactions between ZnO nanoparticles (ZnO NPs) and Pseudomonas putida KT2440 biofilms at different maturity stages were investigated. Three stages of biofilm development were identified according to bacterial adenosine triphosphate (ATP) activity associated with biofilm development process. In the initial biofilm stage 1, the ATP content of bacteria was reduced by more than 90% when biofilms were exposed to ZnO NPs. However, in the mature biofilm stages 2 and 3, the ATP content was only slightly decreased. Biofilms at stage 3 exhibited less susceptibility to ZnO NPs than biofilms at stage 2. These results suggest that more mature biofilms have a significantly higher tolerance to ZnO NPs compared to young biofilms. In addition, biofilms with intact extracellular polymeric substances (EPS) showed higher tolerance to ZnO NPs than those without EPS, indicating that EPS play a key role in alleviating the toxic effects of ZnO NPs. In both pure ZnO NPs and ZnO-HA mixtures, dissolved Zn 2+ originating from the NPs significantly contributed to the overall toxicity. The presence of HA dramatically decreased the toxicity of ZnO NPs due to the binding of Zn 2+ on HA. The combined results from this work suggest that the biofilm maturity stages and environmental constituents (such as humic acid) are important factors to consider when evaluating potential risks of NPs to ecological systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of humic acid on the interactions between zinc oxide nanoparticles and bacterial biofilms

Energy Technology Data Exchange (ETDEWEB)

Ouyang, Kai; Yu, Xiao-Ying; Zhu, Yunlin; Gao, Chunhui; Huang, Qiaoyun; Cai, Peng

2017-12-01

The effects of humic acid (HA) on interactions between ZnO nanoparticles (ZnO NPs) and Pseudomonas putida KT2440 biofilms at different maturity stages were investigated. Three stages of biofilm development were identified according to bacterial adenosine triphosphate (ATP) activity associated with biofilm development process. In the initial biofilm stage 1, the ATP content of bacteria was reduced by more than 90% when biofilms were exposed to ZnO NPs. However, in the mature biofilm stages 2 and 3, the ATP content was only slightly decreased. Biofilms at stage 3 exhibited less susceptibility to ZnO NPs than biofilms at stage 2. These results suggest that more mature biofilms have a significantly higher tolerance to ZnO NPs compared to young biofilms. In addition, biofilms with intact extracellular poly-meric substances (EPS) showed higher tolerance to ZnO NPs than those without EPS, indicating that EPS play a key role in alleviating the toxic effects of ZnO NPs. In both pure ZnO NPs and ZnO-HA mixtures, dissolved Zn²⁺ originating from the NPs significantly contributed to the overall toxicity. The presence of HA dramatically decreased the toxicity of ZnO NPs due to the binding of Zn²⁺ on HA. The combined results from this work suggest that the biofilm maturity stages and environmental constituents (such as humic acid) are important factors to consider when evaluating potential risks of NPs to ecological systems.

Changes in rocket salad phytochemicals within the commercial supply chain: Glucosinolates, isothiocyanates, amino acids and bacterial load increase significantly after processing.

Science.gov (United States)

Bell, Luke; Yahya, Hanis Nadia; Oloyede, Omobolanle Oluwadamilola; Methven, Lisa; Wagstaff, Carol

2017-04-15

Five cultivars of Eruca sativa and a commercial variety of Diplotaxis tenuifolia were grown in the UK (summer) and subjected to commercial growth, harvesting and processing, with subsequent shelf life storage. Glucosinolates (GSL), isothiocyanates (ITC), amino acids (AA), free sugars, and bacterial loads were analysed throughout the supply chain to determine the effects on phytochemical compositions. Bacterial load of leaves increased significantly over time and peaked during shelf life storage. Significant correlations were observed with GSL and AA concentrations, suggesting a previously unknown relationship between plants and endemic leaf bacteria. GSLs, ITCs and AAs increased significantly after processing and during shelf life. The supply chain did not significantly affect glucoraphanin concentrations, and its ITC sulforaphane significantly increased during shelf life in E. sativa cultivars. We hypothesise that commercial processing may increase the nutritional value of the crop, and have added health benefits for the consumer. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Chemical composition and anti-bacterial activity of essential oil from ...

African Journals Online (AJOL)

This work assesses the chemical compositions and in vitro anti-bacterial activities of seed essential oil from Cedrela sinesis (A. Juss.) Roem. seed. which has abundant mineral elements such as K, Ca, Fe. The fatty acid profiles of seed essential oil are characterized by considerable unsaturated fatty acids (90.39%) ...

California Black Oak Drying Problems and the Bacterial Factor.

Science.gov (United States)

1979-01-01

operations in Anderson area and to adjacent kilns by spacing stickers 18 inches apart and Georgia and wondered if bacterial tree drying softwood lumber at...on stickers in a weighted, volatile fatty acids which are the sapwood , and then from the outer, covered pile placed outdoors on the characteristic of...1. JT~~~ Figure 1 —Scanning electron micrographs of nonintected sapwood (A-B) and bacterially infected heartwood (C-D) from

Fermentation of aqueous plant seed extracts by lactic acid bacteria

Energy Technology Data Exchange (ETDEWEB)

Schafner, D.W.; Beuchat, R.L.

1986-05-01

The effects of lactic acid bacterial fermentation on chemical and physical changes in aqueous extracts of cowpea (Vigna unguiculata), peanut (Arachis hypogea), soybean (Glycine max), and sorghum (Sorghum vulgare) were studied. The bacteria investigated were Lactobacillus helveticus, L. delbrueckii, L. casei, L. bulgaricus, L. acidophilus, and Streptococcus thermophilus. Organisms were inoculated individually into all of the seed extracts; L. bulgaricus and S. thermophilus were also evaluated together as inocula for fermenting the legume extracts. During fermentation, bacterial population and changes in titratable acidity, pH, viscosity, and color were measured over a 72 h period at 37 degrees C. Maximum bacterial populations, titratable acidity, pH, and viscosity varied depending upon the type of extract and bacterial strain. The maximum population of each organism was influenced by fermentable carbohydrates, which, in turn, influenced acid production and change in pH. Change in viscosity was correlated with the amount of protein and titratable acidity of products. Color was affected by pasteurization treatment and fermentation as well as the source of extract. In the extracts inoculated simultaneously with L. bulgaricus and S. thermophilus, a synergistic effect resulted in increased bacterial populations, titratable acidity, and viscosity, and decreased pH in all the legume extracts when compared to the extracts fermented with either of these organisms individually. Fermented extracts offer potential as substitutes for cultured dairy products. 24 references.

Bacterial growth on ion exchange resin - investigations with a strong cationic exchanger. Pt. 3. Disinfection with peracetic acid

Energy Technology Data Exchange (ETDEWEB)

Flemming, H.C.

1984-12-01

The suitability of peracetic acid (PAA) for the disinfection of ion exchangers was investigated. 0.02% PAA is suitable for satisfactory disinfection. In this way corrosive effects are strongly reduced. Ca/sup 2+/-ions seem to protect the bacteria, therefore the disinfection should be done with the Na/sup +/-form. The disinfection has no remanent effect and therefore is not suitable for preventing bacterial aftergrowth during off-periods. A combination of silver and disinfectant can accomplish this, until a new, silver-tolerant microflora has evolved. In this case the use of 0.02% PAA is imperative, because higher concentrations will dissolve the silver. As a principle the effectiveness of disinfection procedure should be monitored bacteriologically.

Interactions of plaunotol with bacterial membranes.

Science.gov (United States)

Koga, T; Watanabe, H; Kawada, H; Takahashi, K; Utsui, Y; Domon, H; Ishii, C; Narita, T; Yasuda, H

1998-08-01

Plaunotol, a cytoprotective antiulcer agent, has a bactericidal effect against Helicobacter pylori, which may result from interaction of this compound with the bacterial cell membrane. The purpose of the present study was to confirm that plaunotol interacts with the H. pylori membrane. Membrane fluidities were measured using two stearic acid spin labels, namely 5-doxyl-stearic acid (in which the nitroxide group is located in the upper portion of the bacterial cell membrane) and 16-doxyl-stearic acid methyl ester (in which the nitroxide group is located deeper in the bacterial cell membrane), by means of electron spin resonance. The membrane fluidities of plaunotol-treated cells were significantly increased in the measurements made using the two spin labels. We also attempted to isolate plaunotol-resistant H. pylori in vitro by two different methods. To assess the level of resistance that could be reached, H. pylori was passaged five times on an agar plate containing subinhibitory concentrations of plaunotol or metronidazole. To measure the rate of development of resistance, H. pylori was grown with subinhibitory concentrations (0.25 x MIC) of plaunotol or metronidazole, and quantitatively plated on to medium containing 4 x MIC of the compounds. This treatment was repeated once more. No plaunotol-resistant colonies were selected by the two methods. H. pylori developed resistance to metronidazole easily and at a relatively high rate. The mechanism by which plaunotol directly fluidizes and destroys the H. pylori membrane might make it difficult for this organism to develop resistance to plaunotol. It was confirmed that the bactericidal effects of plaunotol were also shown against Staphylococcus aureus, Streptococcus pneumoniae, Neisseria gonorrhoeae, Moraxella catarrhalis and Haemophilus influenzae. No such effect was seen against Escherichia coli and Pseudomonas aeruginosa.

Arginine- and Polyamine-Induced Lactic Acid Resistance in Neisseria gonorrhoeae.

Directory of Open Access Journals (Sweden)

Zheng Gong

Full Text Available Microbe-derived lactic acid protects women from pathogens in their genital tract. The purpose of this study was to determine lactic acid susceptibility of Neisseria gonorrhoeae, and identify potential acid resistance mechanisms present in this pathogen. Tested in vitro, lactic acid killed all 10 gonococcal strains analyzed in a low pH-dependent manner. Full inactivation occurred at pH 4.5. At low pH, lactic acid treatment resulted in the entry of the DNA-binding fluorochrome propidium iodide into the microbial cells, suggesting that hydrogen ions from lactic acid compromise the integrity of the bacterial cell wall/membrane. Most likely, hydrogen ions also inactivate intracellular proteins since arginine rendered significant protection against lactic acid presumably through action of the gonococcal arginine decarboxylase, an enzyme located in the bacterial cytoplasm. Surprisingly, arginine also lessened lactic acid-mediated cell wall/membrane disruption. This effect is probably mediated by agmatine, a triamine product of arginine decarboxylase, since agmatine demonstrated a stronger protective effect on GC than arginine at equal molar concentration. In addition to agmatine, diamines cadaverine and putrescine, which are generated by bacterial vaginosis-associated microbes, also induced significant resistance to lactic acid-mediated GC killing and cell wall/membrane disruption. These findings suggest that the arginine-rich semen protects gonococci through both neutralization-dependent and independent mechanisms, whereas polyamine-induced acid resistance contributes to the increased risk of gonorrhea in women with bacterial vaginosis.

Bacterial endophytes enhance competition by invasive plants.

Science.gov (United States)

Rout, Marnie E; Chrzanowski, Thomas H; Westlie, Tara K; DeLuca, Thomas H; Callaway, Ragan M; Holben, William E

2013-09-01

Invasive plants can alter soil microbial communities and profoundly alter ecosystem processes. In the invasive grass Sorghum halepense, these disruptions are consequences of rhizome-associated bacterial endophytes. We describe the effects of N2-fixing bacterial strains from S. halepense (Rout and Chrzanowski, 2009) on plant growth and show that bacteria interact with the plant to alter soil nutrient cycles, enabling persistence of the invasive. • We assessed fluxes in soil nutrients for ∼4 yr across a site invaded by S. halepense. We assayed the N2-fixing bacteria in vitro for phosphate solubilization, iron chelation, and production of the plant-growth hormone indole-3-acetic acid (IAA). We assessed the plant's ability to recruit bacterial partners from substrates and vertically transmit endophytes to seeds and used an antibiotic approach to inhibit bacterial activity in planta and assess microbial contributions to plant growth. • We found persistent alterations to eight biogeochemical cycles (including nitrogen, phosphorus, and iron) in soils invaded by S. halepense. In this context, three bacterial isolates solubilized phosphate, and all produced iron siderophores and IAA in vitro. In growth chamber experiments, bacteria were transmitted vertically, and molecular analysis of bacterial community fingerprints from rhizomes indicated that endophytes are also horizontally recruited. Inhibiting bacterial activity with antibiotics resulted in significant declines in plant growth rate and biomass, with pronounced rhizome reductions. • This work suggests a major role of endophytes on growth and resource allocation of an invasive plant. Indeed, bacterial isolate physiology is correlated with invader effects on biogeochemical cycles of nitrogen, phosphate, and iron.

Sphagnum mosses harbour highly specific bacterial diversity during their whole lifecycle.

Science.gov (United States)

Bragina, Anastasia; Berg, Christian; Cardinale, Massimiliano; Shcherbakov, Andrey; Chebotar, Vladimir; Berg, Gabriele

2012-04-01

Knowledge about Sphagnum-associated microbial communities, their structure and their origin is important to understand and maintain climate-relevant Sphagnum-dominated bog ecosystems. We studied bacterial communities of two cosmopolitan Sphagnum species, which are well adapted to different abiotic parameters (Sphagnum magellanicum, which are strongly acidic and ombrotrophic, and Sphagnum fallax, which are weakly acidic and mesotrophic), in three Alpine bogs in Austria by a multifaceted approach. Great differences between bacterial fingerprints of both Sphagna were found independently from the site. This remarkable specificity was confirmed by a cloning and a deep sequencing approach. Besides the common Alphaproteobacteria, we found a discriminative spectrum of bacteria; although Gammaproteobacteria dominated S. magellanicum, S. fallax was mainly colonised by Verrucomicrobia and Planctomycetes. Using this information for fluorescent in situ hybridisation analyses, corresponding colonisation patterns for Alphaproteobacteria and Planctomycetes were detected. Bacterial colonies were found in high abundances inside the dead big hyalocytes, but they were always connected with the living chlorocytes. Using multivariate statistical analysis, the abiotic factors nutrient richness and pH were identified to modulate the composition of Sphagnum-specific bacterial communities. Interestingly, we found that the immense bacterial diversity was transferred via the sporophyte to the gametophyte, which can explain the high specificity of Sphagnum-associated bacteria over long distances. In contrast to higher plants, which acquire their bacteria mainly from the environment, mosses as the phylogenetically oldest land plants maintain their bacterial diversity within the whole lifecycle.

Bacterial Peptide Deformylase Inhibition of Tetrazole-Substituted Biaryl Acid Analogs: Synthesis, Biological Evaluations, and Molecular Docking Study.

Science.gov (United States)

Khan, Firoz A Kalam; Patil, Rajendra H; Patil, Manjiri; Arote, Rohidas; Shinde, Devanand B; Sangshetti, Jaiprakash N

2016-12-01

The synthesis and screening of tetrazole-substituted biaryl acid analogs 7a-l as bacterial peptide deformylase (PDF) enzyme inhibitors is reported. The compounds 7e (IC 50 value = 5.50 μM) and 7g (IC 50 value = 7.25 μM) showed good PDF inhibition activity. The compounds 7e (MIC range = 10.75-11.66 μg/mL) and 7g (MIC range = 8.91-12.83 μg/mL) also showed potent antibacterial activity when compared with the standard ciprofloxacin (MIC range = 25-50 μg/mL). Thus, the active derivatives were not only potent PDF enzyme inhibitors but also efficient antibacterial agents. In order to gain more insight into the binding mode of the compounds with the PDF enzyme, the most active compounds 7e and 7g, the moderately active compound 7k, and the least active compound 7h were docked against the PDF enzyme of Escherichia coli. The docking study of the most active compounds 7e and 7g against the PDF enzyme exhibited good binding properties. Hence, we believe our synthesized compounds 7a-l could serve as reservoir for bacterial PDF inhibitor development. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Direct high-pressure NMR observation of dipicolinic acid leaking from bacterial spore: A crucial step for thermal inactivation.

Science.gov (United States)

Akasaka, Kazuyuki; Maeno, Akihiro; Yamazaki, Akira

2017-12-01

A bacterial spore protects itself with an unusually high concentration (~10% in dry weight of spore) of dipicolinic acid (DPA), the release of which is considered the crucial step for inactivating it under mild pressure and temperature conditions. However, the process of how the spore releases DPA in response to pressure remains obscure. Here we apply 1 H high-resolution high-pressure NMR spectroscopy, for the first time, to the spore suspension of Bacillus subtilis natto and monitor directly and in real-time the leaking process of DPA in response to pressure of 200MPa at 20°C. We find that about one third of the total DPA leaks immediately upon applying pressure, but that the rest leaks slowly in hrs upon decreasing the pressure. Once DPA is fully released from the spore, the proteins of the spore become easily denatured at a mild temperature, e.g., 80°C, much below the temperature commonly used to inactivate spores (121°C). The success of the present experiment opens a new avenue for studying bacterial spores and cells at the molecular level in response to pressure, temperature and other perturbations. Copyright © 2017 Elsevier B.V. All rights reserved.

Is intravesical instillation of hyaluronic acid and chondroitin sulfate useful in preventing recurrent bacterial cystitis? A multicenter case control analysis.

Science.gov (United States)

Gugliotta, Giorgio; Calagna, Gloria; Adile, Giorgio; Polito, Salvatore; Saitta, Salvatore; Speciale, Patrizia; Palomba, Stefano; Perino, Antonino; Granese, Roberta; Adile, Biagio

2015-10-01

Urinary tract infections (UTIs) are common in the female population and, over a lifetime, about half of women have at least one episode of UTI requiring antibiotic therapy. The aim of the current study was to compare two different strategies for preventing recurrent bacterial cystitis: intravesical instillation of hyaluronic acid (HA) plus chondroitin sulfate (CS), and antibiotic prophylaxis with sulfamethoxazole plus trimethoprim. This was a retrospective review of two different cohorts of women affected by recurrent bacterial cystitis. Cases (experimental group) were women who received intravesical instillations of a sterile solution of high concentration of HA + CS in 50 mL water with calcium chloride every week during the 1(st) month and then once monthly for 4 months. The control group included women who received traditional therapy for recurrent cystitis based on daily antibiotic prophylaxis using sulfamethoxazole 200 mg plus trimethoprim 40 mg for 6 weeks. Ninety-eight and 76 patients were treated with experimental and control treatments, respectively. At 12 months after treatment, 69 and 109 UTIs were detected in the experimental and control groups, respectively. The proportion of patients free from UTIs was significantly higher in the experimental than in the control group (36.7% vs. 21.0%; p = 0.03). Experimental treatment was well tolerated and none of the patients stopped it. The intravesical instillation of HA + CS is more effective than long-term antibiotic prophylaxis for preventing recurrent bacterial cystitis. Copyright © 2015. Published by Elsevier B.V.

Amino acid metabolic signaling influences Aedes aegypti midgut microbiome variability.

Directory of Open Access Journals (Sweden)

Sarah M Short

2017-07-01

Full Text Available The mosquito midgut microbiota has been shown to influence vector competence for multiple human pathogens. The microbiota is highly variable in the field, and the sources of this variability are not well understood, which limits our ability to understand or predict its effects on pathogen transmission. In this work, we report significant variation in female adult midgut bacterial load between strains of A. aegypti which vary in their susceptibility to dengue virus. Composition of the midgut microbiome was similar overall between the strains, with 81-92% of reads coming from the same five bacterial families, though we did detect differences in the presence of some bacterial families including Flavobacteriaceae and Entobacteriaceae. We conducted transcriptomic analysis on the two mosquito strains that showed the greatest difference in bacterial load, and found that they differ in transcript abundance of many genes implicated in amino acid metabolism, in particular the branched chain amino acid degradation pathway. We then silenced this pathway by targeting multiple genes using RNA interference, which resulted in strain-specific bacterial proliferation, thereby eliminating the difference in midgut bacterial load between the strains. This suggests that the branched chain amino acid (BCAA degradation pathway controls midgut bacterial load, though the mechanism underlying this remains unclear. Overall, our results indicate that amino acid metabolism can act to influence the midgut microbiota. Moreover, they suggest that genetic or physiological variation in BCAA degradation pathway activity may in part explain midgut microbiota variation in the field.

Characterization of Chemically-Induced Bacterial Ghosts (BGs Using Sodium Hydroxide-Induced Vibrio parahaemolyticus Ghosts (VPGs

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Hyun Jung Park

2016-11-01

Full Text Available Acellular bacterial ghosts (BGs are empty non-living bacterial cell envelopes, commonly generated by controlled expression of the cloned lysis gene E of bacteriophage PhiX174. In this study, Vibrio parahaemolyticus ghosts (VPGs were generated by chemically-induced lysis and the method is based on minimum inhibitory concentration (MIC of sodium hydroxide (NaOH, acetic acid, boric acid, citric acid, maleic acid, hydrochloric acid, and sulfuric acid. The MIC values of the respective chemicals were 3.125, 6.25, <50.0, 25.0, 6.25, 1.56, and 0.781 mg/mL. Except for boric acid, the lysis efficiency reached more than 99.99% at 5 min after treatment of all chemicals. Among those chemicals, NaOH-induced VPGs appeared completely DNA-free, which was confirmed by quantitative real-time PCR. Besides, lipopolysaccharides (LPS extracted from the NaOH-induced VPGs showed no distinctive band on SDS-PAGE gel after silver staining. On the other hand, LPS extracted from wild-type bacterial cells, as well as the organic acids-induced VPGs showed triple major bands and LPS extracted from the inorganic acids-induced VPGs showed double bands. It suggests that some surface structures in LPS of the NaOH-induced VPGs may be lost, weakened, or modified by the MIC of NaOH. Nevertheless, Limulus amoebocyte lysate assay revealed that there is no significant difference in endotoxic activity between the NaOH-induced VPGs and wild-type bacterial cells. Macrophages exposed to the NaOH-induced VPGs at 0.5 × 106 CFU/mL showed cell viability of 97.9%, however, the MIC of NaOH did not reduce the cytotoxic effect of wild-type bacterial cells. Like Escherichia coli LPS, the NaOH-induced VPGs are an excellent activator of pro-inflammatory cytokines (IL-1β and iNOS, anti-inflammatory cytokine (IL-10, and dual activities (IL-6 in the stimulated macrophage cells. On the other hand, the induction of TNF-α mRNA was remarkable in the macrophages exposed with wild-type cells. Scanning

Co-expression of bacterial aspartate kinase and adenylylsulfate reductase genes substantially increases sulfur amino acid levels in transgenic alfalfa (Medicago sativa L.).

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Tong, Zongyong; Xie, Can; Ma, Lei; Liu, Liping; Jin, Yongsheng; Dong, Jiangli; Wang, Tao

2014-01-01

Alfalfa (Medicago sativa L.) is one of the most important forage crops used to feed livestock, such as cattle and sheep, and the sulfur amino acid (SAA) content of alfalfa is used as an index of its nutritional value. Aspartate kinase (AK) catalyzes the phosphorylation of aspartate to Asp-phosphate, the first step in the aspartate family biosynthesis pathway, and adenylylsulfate reductase (APR) catalyzes the conversion of activated sulfate to sulfite, providing reduced sulfur for the synthesis of cysteine, methionine, and other essential metabolites and secondary compounds. To reduce the feedback inhibition of other metabolites, we cloned bacterial AK and APR genes, modified AK, and introduced them into alfalfa. Compared to the wild-type alfalfa, the content of cysteine increased by 30% and that of methionine increased substantially by 60%. In addition, a substantial increase in the abundance of essential amino acids (EAAs), such as aspartate and lysine, was found. The results also indicated a close connection between amino acid metabolism and the tricarboxylic acid (TCA) cycle. The total amino acid content and the forage biomass tested showed no significant changes in the transgenic plants. This approach provides a new method for increasing SAAs and allows for the development of new genetically modified crops with enhanced nutritional value.

Acinetobacter calcoaceticus CSY-P13 Mitigates Stress of Ferulic and p-Hydroxybenzoic Acids in Cucumber by Affecting Antioxidant Enzyme Activity and Soil Bacterial Community

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Fenghui Wu

2018-06-01

Full Text Available Ferulic acid (FA and p-hydroxybenzoic acid (PHBA are main phenolic compounds accumulated in rhizosphere of continuously cropped cucumber, causing stress in plants. Microbial degradation of a mixture of FA and PHBA is not well understood in soil. We isolated a strain CSY-P13 of Acinetobacter calcoaceticus, inoculated it into soil to protect cucumber from FA and PHBA stress, and explored a mechanism underlying the protection. CSY-P13 effectively degraded a mixture of FA and PHBA in culture solution under conditions of 39.37°C, pH 6.97, and 21.59 g L-1 potassium dihydrogen phosphate, giving rise to 4-vinyl guaiacol, vanillin, vanillic acid, and protocatechuic acid. During FA and PHBA degradation, activities of superoxide dismutase (SOD, catalase, ascorbate peroxidase, and dehydroascorbate reductase in CSY-P13 were induced. Inoculated into cucumber-planted soil containing 220 μg g-1 mixture of FA and PHBA, CSY-P13 degraded FA and PHBA in soil, increased plant height, and decreased malonaldehyde, superoxide radical, and hydrogen peroxide levels in leaves. CSY-P13 also enhanced SOD, guaiacol peroxidase, catalase, glutathione peroxidase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase activities; increased ascorbate and glutathione contents; and elevated transcript levels of copper/zinc SOD, manganese SOD, and catalase in leaves under FA and PHBA. Moreover, CSY-P13 increased phosphatase, catalase, urease, and sucrase activities and changed bacterial richness, diversity, and community composition by high throughput sequencing in cucumber-planted soil supplemented with the mixture of FA and PHBA. So CSY-P13 degrades the mixture of FA and PHBA in soil and mitigates stress from the two phenolic compounds in cucumber by activating antioxidant enzymes, changing soil bacterial community, and inducing soil enzymes.

Modulation of Intestinal Barrier and Bacterial Endotoxin Production Contributes to the Beneficial Effect of Nicotinic Acid on Alcohol-Induced Endotoxemia and Hepatic Inflammation in Rats

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Wei Zhong

2015-10-01

Full Text Available Alcohol consumption causes nicotinic acid deficiency. The present study was undertaken to determine whether dietary nicotinic acid supplementation provides beneficial effects on alcohol-induced endotoxin signaling and the possible mechanisms at the gut-liver axis. Male Sprague-Dawley rats were pair-fed the Lieber-DeCarli liquid diets containing ethanol or isocaloric maltose dextrin for eight weeks, with or without dietary supplementation with 750 mg/liter nicotinic acid. Chronic alcohol feeding elevated the plasma endotoxin level and activated hepatic endotoxin signaling cascade, which were attenuated by nicotinic acid supplementation. Alcohol consumption remarkably decreased the mRNA levels of claudin-1, claudin-5, and ZO-1 in the distal intestine, whereas nicotinic acid significantly up-regulated these genes. The concentrations of endotoxin, ethanol, and acetaldehyde in the intestinal contents were increased by alcohol exposure, and niacin supplementation reduced the intestinal endotoxin and acetaldehyde levels. Nicotinic acid supplementation upregulated the intestinal genes involved in aldehyde detoxification via transcriptional regulation. These results demonstrate that modulation of the intestinal barrier function and bacterial endotoxin production accounts for the inhibitory effects of nicotinic acid on alcohol-induced endotoxemia and hepatic inflammation.

Systemic lupus erythematosus and the Crithidia luciliae immunofluorescent test

International Nuclear Information System (INIS)

Whitehouse, I.J.; Fehr, K.; Wagenhaeuser, F.J.

1983-01-01

A comparative study of the Crithidia luciliae immunofluorescence (CL-IF) assay and an adapted Farr radioimmunoassay (RIA), for the measurement of antibodies to native deoxyribonucleic acid, was performed using forty-two sera from patients with systematic lupus erythematosus (SLE) and another forty-two from patients with rheumatoid arthritis. Both assays were specific for SLE. The CL-IF assay was statistically significantly more sensitive than the adapted RIA assay. This significant difference was due to greater sensitivity of the CL-IF assay in the cases of sera from patients with SLE of slight activity. Additional advantages of the CL-IF assay were its use to classify the immunoglobulin types of the antibodies (most commonly IgG or IgM) and to measure complement-fixing antibodies to native deoxyribonucleic acid; it affords a simple method of selecting and following SLE patients at risk of developing severe renal disease. These advantages plus the simplicity and inexpensiveness of the CL-IF assay make it a useful tool, especially for use in small laboratories, for the study of antibodies to native deoxyribonucleic acid in patients with SLE. (orig.) [de

Pilot test of bacterial percolation leaching at Fuzhou uranium mine

International Nuclear Information System (INIS)

Fan Baotuan; Liu Jian; Jiang Yngqiong; Cai Chunhui; Jiang Lang; Zhou Renhua; Tong Changning; Zhang Hongli

2006-01-01

Total 18 t uranium ores of Fuzhou Uranium Mine packed in three or four columns in series were leached by bacterial percolation. The results show that without adding any other chemical oxidant such as sodium chlorate, the leaching rate measured by residue is 91.45%-94.48%, leaching time is 50-60 d, acid consumption is 6.17%-7.75%, and residue grade is 0.0149%-0.0208%. Compared with conventional percolation leaching process, the leaching rate is improved by 3%, leaching time is shorted by 26%, and acid consumption is saved by 34%. Accumulation pattern of ΣFe and F - in the process of leaching is discussed. Influence of F - on bacterial growth, regeneration of barren solution as well as correlative techniques are reviewed. (authors)

In Situ Hydrocarbon Degradation by Indigenous Nearshore Bacterial Populations

International Nuclear Information System (INIS)

Cherrier, J.

2005-01-01

series experiments demonstrated that short-term exposure of petroleum to UV light enhanced hydrocarbon degradation by 48% over that observed for non-photo-oxidized petroleum. Despite the greater bio-availability of the photo-oxidized over the non-photo-oxidized petroleum, an initial lag in CO 2 production was observed indicating potential phototoxicity of the photo- by-products. (delta) 13 C analysis and mass balance calculations reveal that co-metabolism with pinfish resulted in increased hydrocarbon degradation for both photo-oxidized and non-photo-oxidized petroleum each by over 100%. These results demonstrate the cumulative effect of photo-oxidation and co-metabolism on petroleum hydrocarbon degradation by natural bacterial populations indigenous to systems chronically impacted by hydrocarbon input. To address the second objective of this proposal bacterial concentrates were collected from Bayboro Harbor in April 2001 for nucleic acid extraction and subsequent natural radiocarbon abundance analyses. Unfortunately, however, all of these samples were lost due to a faulty compressor in our -70 freezer. The freezer was subsequently repaired and samples were again collected from Bayboro Harbor in June 2002 and again December 2002. Several attempts were made to extract the nucleic acid samples--however, the student was not able to successfully extract and an adequate amount of uncontaminated nucleic acid samples for subsequent natural radiocarbon abundance measurements of the bacterial carbon by accelerator mass spectrometry (i.e. require at least 50 (micro)g carbon for AMS measurement). Consequently, we were not able to address the second objective of this proposed work

Searching for the main anti-bacterial components in artificial Calculus bovis using UPLC and microcalorimetry coupled with multi-linear regression analysis.

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Zang, Qing-Ce; Wang, Jia-Bo; Kong, Wei-Jun; Jin, Cheng; Ma, Zhi-Jie; Chen, Jing; Gong, Qian-Feng; Xiao, Xiao-He

2011-12-01

The fingerprints of artificial Calculus bovis extracts from different solvents were established by ultra-performance liquid chromatography (UPLC) and the anti-bacterial activities of artificial C. bovis extracts on Staphylococcus aureus (S. aureus) growth were studied by microcalorimetry. The UPLC fingerprints were evaluated using hierarchical clustering analysis. Some quantitative parameters obtained from the thermogenic curves of S. aureus growth affected by artificial C. bovis extracts were analyzed using principal component analysis. The spectrum-effect relationships between UPLC fingerprints and anti-bacterial activities were investigated using multi-linear regression analysis. The results showed that peak 1 (taurocholate sodium), peak 3 (unknown compound), peak 4 (cholic acid), and peak 6 (chenodeoxycholic acid) are more significant than the other peaks with the standard parameter estimate 0.453, -0.166, 0.749, 0.025, respectively. So, compounds cholic acid, taurocholate sodium, and chenodeoxycholic acid might be the major anti-bacterial components in artificial C. bovis. Altogether, this work provides a general model of the combination of UPLC chromatography and anti-bacterial effect to study the spectrum-effect relationships of artificial C. bovis extracts, which can be used to discover the main anti-bacterial components in artificial C. bovis or other Chinese herbal medicines with anti-bacterial effects. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

RNA preservation agents and nucleic acid extraction method bias perceived bacterial community composition.

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Ann McCarthy

Full Text Available Bias is a pervasive problem when characterizing microbial communities. An important source is the difference in lysis efficiencies of different populations, which vary depending on the extraction protocol used. To avoid such biases impacting comparisons between gene and transcript abundances in the environment, the use of one protocol that simultaneously extracts both types of nucleic acids from microbial community samples has gained popularity. However, knowledge regarding tradeoffs to combined nucleic acid extraction protocols is limited, particularly regarding yield and biases in the observed community composition. Here, we evaluated a commercially available protocol for simultaneous extraction of DNA and RNA, which we adapted for freshwater microbial community samples that were collected on filters. DNA and RNA yields were comparable to other commonly used, but independent DNA and RNA extraction protocols. RNA protection agents benefited RNA quality, but decreased DNA yields significantly. Choice of extraction protocol influenced the perceived bacterial community composition, with strong method-dependent biases observed for specific phyla such as the Verrucomicrobia. The combined DNA/RNA extraction protocol detected significantly higher levels of Verrucomicrobia than the other protocols, and those higher numbers were confirmed by microscopic analysis. Use of RNA protection agents as well as independent sequencing runs caused a significant shift in community composition as well, albeit smaller than the shift caused by using different extraction protocols. Despite methodological biases, sample origin was the strongest determinant of community composition. However, when the abundance of specific phylogenetic groups is of interest, researchers need to be aware of the biases their methods introduce. This is particularly relevant if different methods are used for DNA and RNA extraction, in addition to using RNA protection agents only for RNA

Heterotrophic bacterial responses to the winter–spring phytoplankton bloom in open waters of the NW Mediterranean

KAUST Repository

Gomes, Ana; Gasol, Josep M.; Estrada, Marta; Franco-Vidal, Leticia; Dí az-Pé rez, Laura; Ferrera, Isabel; Moran, Xose Anxelu G.

2014-01-01

and bacterioplankton biomass and production were complemented with an insight into bacterial physiological structure by single-cell analysis of nucleic acid content [low (LNA) vs. high (HNA)] and membrane integrity (“Live” vs. “Dead” cells). Bacterial production

Furan-based benzene mono- and dicarboxylic acid derivatives as multiple inhibitors of the bacterial Mur ligases (MurC-MurF): experimental and computational characterization

Science.gov (United States)

Perdih, Andrej; Hrast, Martina; Pureber, Kaja; Barreteau, Hélène; Grdadolnik, Simona Golič; Kocjan, Darko; Gobec, Stanislav; Solmajer, Tom; Wolber, Gerhard

2015-06-01

Bacterial resistance to the available antibiotic agents underlines an urgent need for the discovery of novel antibacterial agents. Members of the bacterial Mur ligase family MurC-MurF involved in the intracellular stages of the bacterial peptidoglycan biosynthesis have recently emerged as a collection of attractive targets for novel antibacterial drug design. In this study, we have first extended the knowledge of the class of furan-based benzene-1,3-dicarboxylic acid derivatives by first showing a multiple MurC-MurF ligase inhibition for representatives of the extended series of this class. Steady-state kinetics studies on the MurD enzyme were performed for compound 1, suggesting a competitive inhibition with respect to ATP. To the best of our knowledge, compound 1 represents the first ATP-competitive MurD inhibitor reported to date with concurrent multiple inhibition of all four Mur ligases (MurC-MurF). Subsequent molecular dynamic (MD) simulations coupled with interaction energy calculations were performed for two alternative in silico models of compound 1 in the UMA/ d-Glu- and ATP-binding sites of MurD, identifying binding in the ATP-binding site as energetically more favorable in comparison to the UMA/ d-Glu-binding site, which was in agreement with steady-state kinetic data. In the final stage, based on the obtained MD data novel furan-based benzene monocarboxylic acid derivatives 8- 11, exhibiting multiple Mur ligase (MurC-MurF) inhibition with predominantly superior ligase inhibition over the original series, were discovered and for compound 10 it was shown to possess promising antibacterial activity against S. aureus. These compounds represent novel leads that could by further optimization pave the way to novel antibacterial agents.

Weak organic acid stress in Bacillus subtilis

NARCIS (Netherlands)

ter Beek, A.S.

2009-01-01

Weak organic acids are commonly used food preservatives that protect food products from bacterial contamination. A variety of spore-forming bacterial species pose a serious problem to the food industry by causing extensive food spoilage or even food poisoning. Understanding the mechanisms of

Pervasive Selection for Cooperative Cross-Feeding in Bacterial Communities.

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Sebastian Germerodt

2016-06-01

Full Text Available Bacterial communities are taxonomically highly diverse, yet the mechanisms that maintain this diversity remain poorly understood. We hypothesized that an obligate and mutual exchange of metabolites, as is very common among bacterial cells, could stabilize different genotypes within microbial communities. To test this, we developed a cellular automaton to model interactions among six empirically characterized genotypes that differ in their ability and propensity to produce amino acids. By systematically varying intrinsic (i.e. benefit-to-cost ratio and extrinsic parameters (i.e. metabolite diffusion level, environmental amino acid availability, we show that obligate cross-feeding of essential metabolites is selected for under a broad range of conditions. In spatially structured environments, positive assortment among cross-feeders resulted in the formation of cooperative clusters, which limited exploitation by non-producing auxotrophs, yet allowed them to persist at the clusters' periphery. Strikingly, cross-feeding helped to maintain genotypic diversity within populations, while amino acid supplementation to the environment decoupled obligate interactions and favored auxotrophic cells that saved amino acid production costs over metabolically autonomous prototrophs. Together, our results suggest that spatially structured environments and limited nutrient availabilities should facilitate the evolution of metabolic interactions, which can help to maintain genotypic diversity within natural microbial populations.

Primordial soup was edible: abiotically produced Miller-Urey mixture supports bacterial growth.

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Xie, Xueshu; Backman, Daniel; Lebedev, Albert T; Artaev, Viatcheslav B; Jiang, Liying; Ilag, Leopold L; Zubarev, Roman A

2015-09-28

Sixty years after the seminal Miller-Urey experiment that abiotically produced a mixture of racemized amino acids, we provide a definite proof that this primordial soup, when properly cooked, was edible for primitive organisms. Direct admixture of even small amounts of Miller-Urey mixture strongly inhibits E. coli bacteria growth due to the toxicity of abundant components, such as cyanides. However, these toxic compounds are both volatile and extremely reactive, while bacteria are highly capable of adaptation. Consequently, after bacterial adaptation to a mixture of the two most abundant abiotic amino acids, glycine and racemized alanine, dried and reconstituted MU soup was found to support bacterial growth and even accelerate it compared to a simple mixture of the two amino acids. Therefore, primordial Miller-Urey soup was perfectly suitable as a growth media for early life forms.

CRISPR/Cas systems: new players in gene regulation and bacterial physiology

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David eWeiss

2014-04-01

Full Text Available CRISPR-Cas systems are bacterial defenses against foreign nucleic acids derived from bacteriophages, plasmids or other sources. These systems are targeted in an RNA-dependent, sequence-specific manner, and are also adaptive, providing protection against previously encountered foreign elements. In addition to their canonical function in defense against foreign nucleic acid, their roles in various aspects of bacterial physiology are now being uncovered. We recently revealed a role for a Cas9-based Type II CRISPR-Cas system in the control of endogenous gene expression, a novel form of prokaryotic gene regulation. Cas9 functions in association with two small RNAs to target and alter the stability of an endogenous transcript encoding a bacterial lipoprotein (BLP. Since BLPs are recognized by the host innate immune protein Toll-like Receptor 2 (TLR2, CRISPR-Cas-mediated repression of BLP expression facilitates evasion of TLR2 by the intracellular bacterial pathogen Francisella novicida, and is essential for its virulence. Here we describe the Cas9 regulatory system in detail, as well as data on its role in controlling virulence traits of Neisseria meningitidis and Campylobacter jejuni. We also discuss potential roles of CRISPR-Cas systems in the response to envelope stress and other aspects of bacterial physiology. Since ~45% of bacteria and ~83% of Archaea encode these machineries, the newly appreciated regulatory functions of CRISPR-Cas systems are likely to play broad roles in controlling the pathogenesis and physiology of diverse prokaryotes.

Amplification of deoxyribonucleic acid (DNA) fragment using two ...

African Journals Online (AJOL)

user

2011-04-11

Apr 11, 2011 ... polymerases on this method, whether different lengths of. DNA fragments could be amplified by two-step PCR and the difference of DNA product quality produced by the two methods. MATERIALS AND METHODS. PCR template and reagents. Enterobacteria phage lambda DNA (GenBank no: V00636) ...

The effects of ionizing radiation on deoxyribonucleic acid

International Nuclear Information System (INIS)

Cullis, P.M.; Jones, G.D.D.; Lea, J.; Symons, M.C.R.; Sweeney, M.

1987-01-01

Exposure of frozen, deoxygenated, aqueous solutions of DNA to 60 Co γ-rays at 77 K results in the formation of guanine-centred radical-cations (Gsup(radical +)) and thymine-centred radical-anions (Tsup(radical -)). Both these primary centres are thought to be capable of inducing DNA strand-breaks, both single (SSB) and double (DSB). When low concentrations of a range of water-soluble thiols were added, there was no change in the initial yield of Gsup(radical +) and Tsup(radical -) as judged from the e.s.r. spectra. However, on annealing, the normal pattern of radical reactions was abruptly modified at ca. 200 ± 5 K, with the DNA-centred radicals being dramatically reduced in concentration with the concomitant growth of e.s.r. signals characteristic of RSsup(radical) - SR - radical-anions. For example, for solutions containing one thiol molecule per 25 base-pairs, there was a loss of ca. 50% in the concentration of DNA radicals at this temperature. Using plasmid DNA, the change in the numbers of SSBs and DSBs was monitored when various thiols were present. There was a marked fall in the yields of both these events, in accord with the e.s.r. results. It is concluded that these thiols react by hydrogen-atom donation to various DNA radicals thereby forming RSsup(radical) radicals which rapidly form RSsup(radical)SR - radical-anions. It seems that, under our conditions, neither of these sulphur radicals is able to react with DNA. In the presence of oxygen, the results are less definitive, the degree of repair being a function of the relative concentrations of oxygen and thiol. E.s.r. evidence for the formation of DNA-centred peroxy radicals and their reaction with thiols is presented, and also there is evidence for the addition of oxygen to RSsup(radical) radicals to give RSOsup(anion radical) 2 radicals. The latter are probably able to react with DNA. (author)

Processing of micro-nano bacterial cellulose with hydrolysis method as a reinforcing bioplastic

Science.gov (United States)

Maryam, Maryam; Dedy, Rahmad; Yunizurwan, Yunizurwan

2017-01-01

Nanotechnology is the ability to create and manipulate atoms and molecules on the smallest of scales. Their size allows them to exhibit novel and significantly improved physical, chemical, biological properties, phenomena, and processes because of their size. The purpose of this research is obtaining micro-nano bacterial cellulose as reinforcing bioplastics. Bacterial cellulose (BC) was made from coconut water for two weeks. BC was dried and grinded. Bacterial cellulose was given purification process with NaOH 5% for 6 hours. Making the micro-nano bacterial cellulose with hydrolysis method. Hydrolysis process with hydrochloric acid (HCl) at the conditions 3,5M, 55°C, 6 hours. Drying process used spray dryer. The hydrolysis process was obtained bacterial cellulose with ±7 μm. The addition 2% micro-nano bacterial cellulose as reinforcing in bioplastics composite can improve the physical characteristics.

Processing of micro-nano bacterial cellulose with hydrolysis method as a reinforcing bioplastic

International Nuclear Information System (INIS)

Maryam, Maryam; Yunizurwan, Yunizurwan; Dedy, Rahmad

2017-01-01

Nanotechnology is the ability to create and manipulate atoms and molecules on the smallest of scales. Their size allows them to exhibit novel and significantly improved physical, chemical, biological properties, phenomena, and processes because of their size. The purpose of this research is obtaining micro-nano bacterial cellulose as reinforcing bioplastics. Bacterial cellulose (BC) was made from coconut water for two weeks. BC was dried and grinded. Bacterial cellulose was given purification process with NaOH 5% for 6 hours. Making the micro-nano bacterial cellulose with hydrolysis method. Hydrolysis process with hydrochloric acid (HCl) at the conditions 3,5M, 55°C, 6 hours. Drying process used spray dryer. The hydrolysis process was obtained bacterial cellulose with ±7 μm. The addition 2% micro-nano bacterial cellulose as reinforcing in bioplastics composite can improve the physical characteristics. (paper)

Effects of bacterial direct-fed microbials on ruminal characteristics, methane emission, and milk fatty acid composition in cows fed high- or low-starch diets.

Science.gov (United States)

Philippeau, C; Lettat, A; Martin, C; Silberberg, M; Morgavi, D P; Ferlay, A; Berger, C; Nozière, P

2017-04-01

This study investigated the effects of bacterial direct-fed microbials (DFM) on ruminal fermentation and microbial characteristics, methane (CH 4 ) emission, diet digestibility, and milk fatty acid (FA) composition in dairy cows fed diets formulated to induce different ruminal volatile fatty acid (VFA) profiles. Eight ruminally cannulated dairy cows were divided into 2 groups based on parity, days in milk, milk production, and body weight. Cows in each group were fed either a high-starch (38%, HS) or a low-starch (2%, LS) diet in a 55:45 forage-to-concentrate ratio on a dry matter (DM) basis. For each diet, cows were randomly assigned to 1 of 4 treatments in a Latin square design of (1) control (CON); (2) Propionibacterium P63 (P63); (3) P63 plus Lactobacillus plantarum 115 (P63+Lp); (4) P63 plus Lactobacillus rhamnosus 32 (P63+Lr). Strains of DFM were administered at 10 10 cfu/d. Methane emission (using the sulfur hexafluoride tracer technique), total-tract digestibility, dry matter intake, and milk production and composition were quantified in wk 3. Ruminal fermentation and microbial characteristics were measured in wk 4. Data were analyzed using the mixed procedure of SAS (SAS Institute Inc., Cary, NC). The 2 diets induced different ruminal VFA profiles, with a greater proportion of propionate at the expense of acetate and butyrate for the HS diet. Greater concentrations of total bacteria and selected bacterial species of methanogenic Archaea were reported for the HS diet, whereas the protozoa concentration in HS decreased. For both diets, bacterial DFM supplementation raised ruminal pH (+0.18 pH units, on average) compared with CON. Irrespective of diet, P63+Lp and P63+Lr increased ruminal cellulase activity (3.8-fold, on average) compared with CON, but this effect was not associated with variations in ruminal microbial numbers. Irrespective of diet, no effect of bacterial DFM on ruminal VFA was observed. For the LS diet, supplementing cows with P63+Lr tended

Sequence analysis of putative swrW gene required for surfactant ...

African Journals Online (AJOL)

Serratia marcescens produces biosurfactant serrawettin, essential for its population migration behavior. Serrawettin W1 was revealed to be an antibiotic serratamolide that makes it significant for deoxyribonucleic acid (DNA) and protein sequence analysis. Four nucleotide and amino-acid sequences from local strains ...

Emerging Role of D-Amino Acid Metabolism in the Innate Defense

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Jumpei Sasabe

2018-05-01

Full Text Available Mammalian innate and adaptive immune systems use the pattern recognition receptors, such as toll-like receptors, to detect conserved bacterial and viral components. Bacteria synthesize diverse D-amino acids while eukaryotes and archaea generally produce two D-amino acids, raising the possibility that many of bacterial D-amino acids are bacteria-specific metabolites. Although D-amino acids have not been identified to bind to any known pattern recognition receptors, D-amino acids are enantioselectively recognized by some other receptors and enzymes including a flavoenzyme D-amino acid oxidase (DAO in mammals. At host–microbe interfaces in the neutrophils and intestinal mucosa, DAO catalyzes oxidation of bacterial D-amino acids, such as D-alanine, and generates H2O2, which is linked to antimicrobial activity. Intestinal DAO also modifies the composition of microbiota through modulation of growth for some bacteria that are dependent on host nutrition. Furthermore, regulation and recognition of D-amino acids in mammals have additional meanings at various host–microbe interfaces; D-phenylalanine and D-tryptophan regulate chemotaxis of neutrophils through a G-coupled protein receptor, D-serine has a bacteriostatic role in the urinary tract, D-phenylalanine and D-leucine inhibit innate immunity through the sweet taste receptor in the upper airway, and D-tryptophan modulates immune tolerance in the lower airway. This mini-review highlights recent evidence supporting the hypothesis that D-amino acids are utilized as inter-kingdom communication at host–microbe interface to modulate bacterial colonization and host defense.

Isolation, characterization, and aggregation of a structured bacterial matrix precursor.

Science.gov (United States)

Chai, Liraz; Romero, Diego; Kayatekin, Can; Akabayov, Barak; Vlamakis, Hera; Losick, Richard; Kolter, Roberto

2013-06-14

Biofilms are surface-associated groups of microbial cells that are embedded in an extracellular matrix (ECM). The ECM is a network of biopolymers, mainly polysaccharides, proteins, and nucleic acids. ECM proteins serve a variety of structural roles and often form amyloid-like fibers. Despite the extensive study of the formation of amyloid fibers from their constituent subunits in humans, much less is known about the assembly of bacterial functional amyloid-like precursors into fibers. Using dynamic light scattering, atomic force microscopy, circular dichroism, and infrared spectroscopy, we show that our unique purification method of a Bacillus subtilis major matrix protein component results in stable oligomers that retain their native α-helical structure. The stability of these oligomers enabled us to control the external conditions that triggered their aggregation. In particular, we show that stretched fibers are formed on a hydrophobic surface, whereas plaque-like aggregates are formed in solution under acidic pH conditions. TasA is also shown to change conformation upon aggregation and gain some β-sheet structure. Our studies of the aggregation of a bacterial matrix protein from its subunits shed new light on assembly processes of the ECM within bacterial biofilms.

Tet38 Efflux Pump Affects Staphylococcus aureus Internalization by Epithelial Cells through Interaction with CD36 and Contributes to Bacterial Escape from Acidic and Nonacidic Phagolysosomes.

Science.gov (United States)

Truong-Bolduc, Q C; Khan, N S; Vyas, J M; Hooper, D C

2017-02-01

We previously reported that the Tet38 efflux pump is involved in internalization of Staphylococcus aureus by A549 lung epithelial cells. A lack of tet38 reduced bacterial uptake by A549 cells to 36% of that of the parental strain RN6390. Using invasion assays coupled with confocal microscopy imaging, we studied the host cell receptor(s) responsible for bacterial uptake via interaction with Tet38. We also assessed the ability of S. aureus to survive following alkalinization of the phagolysosomes by chloroquine. Antibody to the scavenger receptor CD36 reduced the internalization of S. aureus RN6390 by A549 cells, but the dependence on CD36 was reduced in QT7 tet38, suggesting that an interaction between Tet38 and CD36 contributed to S. aureus internalization. Following fusion of the S. aureus-associated endosomes with lysosomes, alkalinization of the acidic environment with chloroquine led to a rapid increase in the number of S. aureus RN6390 bacteria in the cytosol, followed by a decrease shortly thereafter. This effect of chloroquine was not seen in the absence of intact Tet38 in mutant QT7. These data taken together suggest that Tet38 plays a role both in bacterial internalization via interaction with CD36 and in bacterial escape from the phagolysosomes. Copyright © 2017 American Society for Microbiology.

The effect of temperature on the fatty acids and isozymes of a psychrotrophic and two mesophilic species of Xenorhabdus, a bacterial symbiont of entomopathogenic nematodes

Energy Technology Data Exchange (ETDEWEB)

He, H. [Wisconsin Univ., Dept. of Biological Sciences, Milwaukee, WI (United States); Gordon, R. [Prince Edward Island Univ., Dept. of Biology, Charlottetown, PE (Canada); Gow, J. A. [Memorial University of Newfoundland, St. John' s NF (Canada)

2001-05-01

Generation times relative to temperature were determined for four strains of Xenorhabdus bacteria that represented three geographically distinct species in order to study the capacity of these bacteria to adapt to changes in temperature, as shown by changes in fatty acid composition. Species of the genus Xenorhabdus are carried in the gut of non-feeding infective juvenile nematodes where they release antibacterial and antifungal compounds, to create a non-competitive environment for nematode and bacterial growth. One of the species investigated was psychotropic (i.e. thriving at low temperatures), the other two mesophilic (i.e. growing at moderate temperatures). Results showed that as temperatures declined, proportions of two of the major fatty acids increased significantly in all strains, while the proportion of the prevalent fatty acid (palmitic acid) decreased. Certain other fatty acids decreased with declining temperatures in all strains. The synthesis of isozymes in response to changing temperatures was also investigated. Results showed a broad capacity for physiological temperature adaptation among strains of different climatic origin. It is suggested that these results support the proposition that entomopathogenic bacteria associated with nematodes adjust to temperature changes physiologically by altering the synthesis of isozymes. 36 refs.,6 tabs.

Synthesis and antibacterial activity of some Schiff bases derived from 4-aminobenzoic acid

Directory of Open Access Journals (Sweden)

JIGNA PAREKH

2005-10-01

Full Text Available The following Schiff bases have been synthesized: (1 4-[(2-chlorobenzylidene amino]benzoic acid [JP1], (2 4-[(furan-2-ylmethyleneamino]benzoic acid [JP2], (3 4-[(3-phenylallylideneamino]benzoic acid [JP3], (4 4-[(2-hydroxybenzylidene amino]benzoic acid [JP4], (5 4-[(4-hydroxy-3-methoxybenzylideneamino]benzoic acid [JP5] and (6 4-[(3-nitrobenzylideneamino]benzoic acid [JP6]. They were screened as potential antibacterial agents against a number of medically important bacterial strains. The antibacterial activity was studied against A. faecalis ATCC 8750, E. aerogenes ATCC 13048, E. coli ATCC 25922, K. pneumoniae NCIM 2719, S. aureus ATCC 25923, P. vulgaris NCIM 8313, P. aeruginosa ATCC 27853 and S. typhimurium ATCC 23564. The antibacterial activity was evaluated using the Agar Ditch method. The solvents used were 1,4-dioxane and dimethyl sulfoxide. Different effects of the compounds were found in the bacterial strains investigated and the solvents used, suggesting, once again, that the antibacterial activity is dependent on the molecular structure of the compound, the solvent used and the bacterial strain under consideration. In the present work, 1,4-dioxane proved to be a good solvent in inhibiting the above stated bacterial strains.

Degradation of amino acids to short-chain fatty acids in humans. An in vitro study

DEFF Research Database (Denmark)

Rasmussen, H S; Holtug, K; Mortensen, P B

1988-01-01

Short-chain fatty acids (SCFA) originate mainly in the colon through bacterial fermentation of polysaccharides. To test the hypothesis that SCFA may originate from polypeptides as well, the production of these acids from albumin and specific amino acids was examined in a faecal incubation system....... Albumin was converted to all C2-C5-fatty acids, whereas amino acids generally were converted to specific SCFA, most often through the combination of a deamination and decarboxylation of the amino acids, although more complex processes also took place. This study indicates that a part of the intestinal...

[Analysis of the bacterial community developing in the course of Sphagnum moss decomposition].

Science.gov (United States)

Kulichevskaia, I S; Belova, S E; Kevbrin, V V; Dedysh, S N; Zavarzin, G A

2007-01-01

Slow degradation of organic matter in acidic Sphagnum peat bogs suggests a limited activity of organotrophic microorganisms. Monitoring of the Sphagnum debris decomposition in a laboratory simulation experiment showed that this process was accompanied by a shift in the water color to brownish due to accumulation of humic substances and by the development of a specific bacterial community with a density of 2.4 x 10(7) cells ml(-1). About half of these organisms are metabolically active and detectable with rRNA-specific oligonucleotide probes. Molecular identification of the components of this microbial community showed the numerical dominance of bacteria affiliated with the phyla Alphaproteobacteria, Actinobacteria, and Phanctomycetes. The population sizes of Firmicutes and Bacteroidetes, which are believed to be the main agents of bacterially-mediated decomposition in eutrophic wetlands, were low. The numbers of planctomycetes increased at the final stage of Sphagnum decomposition. The representative isolates of Alphaproteobacteria were able to utilize galacturonic acid, the only low-molecular-weight organic compound detected in the water samples; the representatives of Planctomycetes were able to decompose some heteropolysaccharides, which points to the possible functional role of these groups of microorganisms in the community under study. Thus, the composition of the bacterial community responsible for Sphagnum decomposition in acidic and low-mineral oligotrophic conditions seems to be fundamentally different from that of the bacterial community which decomposes plant debris in eutrophic ecosystems at neutral pH.

Total volatile fatty acids and bacterial production rates as affected by rations containing untreated or ammonia (urea) treated rice straw in croos-bred cattle

International Nuclear Information System (INIS)

Puri, J.P.; Gupta, B.N.

1990-01-01

An experiment was conducted to study the effect of feeding ammoniated rice straw on ruminal total volatile fatty acid (TVFA) and bacterial production rates. Twelve karan swiss, male, rumen fistulated calves (2-2.5 yrs) were divided in three equal groups. Animals were offered rice straw either untreated (A) or 4 per cent urea+40 per cent moisture treated and ensiled for 30 days (B) or 5 per cent urea+30 per cent moisture treated and ensiled for 30 days (C). Protein requirements were met through concentrate mixture. Levels of NH 3 -N and TCA-precipitable-N in strained rumen liquor (SRL) were significantly higher (20.34±0.022, 63.26±0.81 (B), 20.78±0.41, 64.98±0.87 (C) (mg/100 ml SRL) in groups fed ammoniated ±0.31, 45.94±1.91 mg/100 ml S RL), respectively. The bacterial production rates in the rumen (g/day) were significantly higher in groups B and C as compared to group A. TVFA concentrations (mmole/100 ml SRL ) and TVFA production rates (mmole/d) were also significantly higher in groups B and C as compared to group A. The bacterial production rates were significantly co-related with TVFA, NH 3 -N, TCA precipitable-N concentration in the rumen and ATP production. Multiple regression equations relating bacterial production rates with (i)NH 3 -N and TVFA concentration in the rumen, (ii)NH 3 -N and TVFA production rates and (iii)NH 3 -N and ATP produced were also developed. (author). 18 refs., 2 tabs

Recombinant bacterial hemoglobin alters metabolism of Aspergillus niger

DEFF Research Database (Denmark)

Hofmann, Gerald; Diano, Audrey; Nielsen, Jens

2009-01-01

, the fungus will produce various by-products like organic acids and polyols. In order to circumvent this problem we here study the effects of the expression of a bacterial hemoglobin protein on the metabolism of A. niger. We integrated the vgb gene from Vitreoscilla sp. into the genome at the pyrA locus...

Enzyme-mediated bacterial biodegradation of an azo dye (C.I. Acid blue 113): reuse of treated dye wastewater in post-tanning operations.

Science.gov (United States)

Senthilvelan, T; Kanagaraj, J; Panda, R C

2014-11-01

"Dyeing" is a common practice used to color the hides during the post-tanning operations in leather processing generating plenty of wastewater. The waste stream containing dye as pollutant is severely harmful to living beings. An azo dye (C.I. Acid Blue 113) has been biodegraded effectively by bacterial culture mediated with azoreductase enzyme to reduce the pollution load in the present investigation. The maximum rate of dye degradation was found to be 96 ± 4 and 92 ± 4 % for the initial concentrations of 100 and 200 mg/l, respectively. The enzyme activity was measured using NADH as a substrate. Fourier transform infrared spectroscopy (FT-IR) analysis was confirmed that the transformation of azo linkage could be transformed into N2 or NH3 or incorporated into complete biomass. Breaking down of dye molecules to various metabolites (such as aniline, naphthalene-1,4-diamine, 3-aminobenzenesulfonic acid, naphthalene-1-sulfonic acid, 8-aminonaphthalene-1-sulfonic acid, 5,8-diaminonaphthalene-1-sulfonic acid) was confirmed by gas chromatography and mass spectra (GC-MS) and mass (electrospray ionization (ESI)) spectra analysis. The treated wastewater could be reused for dyeing operation in the leather processing, and the properties of produced leather were evaluated by conventional methods that revealed to have improved dye penetration into the grain layer of experimental leather sample and resulted in high levelness of dyeing, which helps to obtain the desired smoothness and soft leather properties.

Avoiding acidic region streaking in two-dimensional gel electrophoresis: case study with two bacterial whole cell protein extracts.

Science.gov (United States)

Roy, Arnab; Varshney, Umesh; Pal, Debnath

2014-09-01

Acidic region streaking (ARS) is one of the lacunae in two-dimensional gel electrophoresis (2DE) of bacterial proteome. This streaking is primarily caused by nucleic acid (NuA) contamination and poses major problem in the downstream processes like image analysis and protein identification. Although cleanup and nuclease digestion are practiced as remedial options, these strategies may incur loss in protein recovery and perform incomplete removal of NuA. As a result, ARS has remained a common observation across publications, including the recent ones. In this work, we demonstrate how ultrasound wave can be used to shear NuA in plain ice-cooled water, facilitating the elimination of ARS in the 2DE gels without the need for any additional sample cleanup tasks. In combination with a suitable buffer recipe, IEF program and frequent paper-wick changing approach, we are able to reproducibly demonstrate the production of clean 2DE gels with improved protein recovery and negligible or no ARS. We illustrate our procedure using whole cell protein extracts from two diverse organisms, Escherichia coli and Mycobacterium smegmatis. Our designed protocols are straightforward and expected to provide good 2DE gels without ARS, with comparable times and significantly lower cost.

Dynamic metabolic exchange governs a marine algal-bacterial interaction.

Science.gov (United States)

Segev, Einat; Wyche, Thomas P; Kim, Ki Hyun; Petersen, Jörn; Ellebrandt, Claire; Vlamakis, Hera; Barteneva, Natasha; Paulson, Joseph N; Chai, Liraz; Clardy, Jon; Kolter, Roberto

2016-11-18

Emiliania huxleyi is a model coccolithophore micro-alga that generates vast blooms in the ocean. Bacteria are not considered among the major factors influencing coccolithophore physiology. Here we show through a laboratory model system that the bacterium Phaeobacter inhibens , a well-studied member of the Roseobacter group, intimately interacts with E. huxleyi. While attached to the algal cell, bacteria initially promote algal growth but ultimately kill their algal host. Both algal growth enhancement and algal death are driven by the bacterially-produced phytohormone indole-3-acetic acid. Bacterial production of indole-3-acetic acid and attachment to algae are significantly increased by tryptophan, which is exuded from the algal cell. Algal death triggered by bacteria involves activation of pathways unique to oxidative stress response and programmed cell death. Our observations suggest that bacteria greatly influence the physiology and metabolism of E. huxleyi. Coccolithophore-bacteria interactions should be further studied in the environment to determine whether they impact micro-algal population dynamics on a global scale.

Bacterial Reaction Centers Purified with Styrene Maleic Acid Copolymer Retain Native Membrane Functional Properties and Display Enhanced Stability**

Science.gov (United States)

Swainsbury, David J K; Scheidelaar, Stefan; van Grondelle, Rienk; Killian, J Antoinette; Jones, Michael R

2014-01-01

Integral membrane proteins often present daunting challenges for biophysical characterization, a fundamental issue being how to select a surfactant that will optimally preserve the individual structure and functional properties of a given membrane protein. Bacterial reaction centers offer a rare opportunity to compare the properties of an integral membrane protein in different artificial lipid/surfactant environments with those in the native bilayer. Here, we demonstrate that reaction centers purified using a styrene maleic acid copolymer remain associated with a complement of native lipids and do not display the modified functional properties that typically result from detergent solubilization. Direct comparisons show that reaction centers are more stable in this copolymer/lipid environment than in a detergent micelle or even in the native membrane, suggesting a promising new route to exploitation of such photovoltaic integral membrane proteins in device applications. PMID:25212490

Different temperatures select distinctive acetic acid bacteria species and promotes organic acids production during Kombucha tea fermentation.

Science.gov (United States)

De Filippis, Francesca; Troise, Antonio Dario; Vitaglione, Paola; Ercolini, Danilo

2018-08-01

Kombucha is a traditional beverage produced by tea fermentation, carried out by a symbiotic consortium of bacteria and yeasts. Acetic Acid Bacteria (AAB) usually dominate the bacterial community of Kombucha, driving the fermentative process. The consumption of this beverage was often associated to beneficial effects for the health, due to its antioxidant and detoxifying properties. We characterized bacterial populations of Kombucha tea fermented at 20 or 30 °C by using culture-dependent and -independent methods and monitored the concentration of gluconic and glucuronic acids, as well as of total polyphenols. We found significant differences in the microbiota at the two temperatures. Moreover, different species of Gluconacetobacter were selected, leading to a differential abundance of gluconic and glucuronic acids. Copyright © 2018 Elsevier Ltd. All rights reserved.

Impact of oil contamination and biostimulation on the diversity of indigenous bacterial communities in soil microcosms

NARCIS (Netherlands)

Evans, FF; Rosado, AS; Sebastian, GV; Casella, R; Machado, PLOA; Holmstrom, C; Kjelleberg, S; van Elsas, JD; Seldin, L

2004-01-01

The aim of this study was to analyse the effect of oil contamination and biostimulation (soil pH raise, and nitrogen, phosphate and sulphur addition) on the diversity of a bacterial community of an acidic Cambisol under Atlantic Forest. The experiment was based on the enumeration of bacterial

A Survey of Bacterial and Fungal Oppurtunistic Infections among ...

African Journals Online (AJOL)

The bacterial pathogens were isolated using Blood and Chocolate agar plates and identified biochemically except the Acid Fast Bacilli (AFB) which was tested in all the HIV positive samples by Ziehl Neelson staining technique. The fungal pathogens were isolated using Sabouraud Dextrose Agar (SDA) with antibiotics and ...

Indole-3-acetic acid biosynthetic pathway and aromatic amino acid aminotransferase activities in Pantoea dispersa strain GPK.

Science.gov (United States)

Kulkarni, G B; Nayak, A S; Sajjan, S S; Oblesha, A; Karegoudar, T B

2013-05-01

This investigation deals with the production of IAA by a bacterial isolate Pantoea dispersa strain GPK (PDG) identified by 16S rRNA gene sequence analysis. HPLC and Mass spectral analysis of metabolites from bacterial spent medium revealed that, IAA production by PDG is Trp-dependent and follows indole-3-pyruvic acid (IPyA) pathway. Substrate specificity study of aromatic amino acid aminotransferase (AAT) showed high activities, only when tryptophan (Trp) and α-ketoglutarate (α-kg) were used as substrates. AAT is highly specific for Trp and α-kg as amino group donor and acceptor, respectively. The effect of exogenous IAA on bacterial growth was established. Low concentration of exogenous IAA induced the growth, whereas high concentration decreased the growth of bacterium. PDG treatment significantly increased the root length, shoot length and dry mass of the chickpea and pigeon pea plants. © 2013 The Society for Applied Microbiology.

Bacterial streamers in curved microchannels

Science.gov (United States)

Rusconi, Roberto; Lecuyer, Sigolene; Guglielmini, Laura; Stone, Howard

2009-11-01

Biofilms, generally identified as microbial communities embedded in a self-produced matrix of extracellular polymeric substances, are involved in a wide variety of health-related problems ranging from implant-associated infections to disease transmissions and dental plaque. The usual picture of these bacterial films is that they grow and develop on surfaces. However, suspended biofilm structures, or streamers, have been found in natural environments (e.g., rivers, acid mines, hydrothermal hot springs) and are always suggested to stem from a turbulent flow. We report the formation of bacterial streamers in curved microfluidic channels. By using confocal laser microscopy we are able to directly image and characterize the spatial and temporal evolution of these filamentous structures. Such streamers, which always connect the inner corners of opposite sides of the channel, are always located in the middle plane. Numerical simulations of the flow provide evidences for an underlying hydrodynamic mechanism behind the formation of the streamers.

Interaction of Atmospheric-Pressure Air Microplasmas with Amino Acids as Fundamental Processes in Aqueous Solution.

Directory of Open Access Journals (Sweden)

Renwu Zhou

Full Text Available Plasma medicine is a relatively new field that investigates potential applications of cold atmospheric-pressure plasmas in bioengineering, such as for bacterial inactivation and degradation of organic molecules in water. In order to enunciate mechanisms of bacterial inactivation at molecular or atomic levels, we investigated the interaction of atmospheric-pressure air microplasmas with amino acids in aqueous solution by using high-resolution mass spectrometry (HRMS. Results show that the oxidation effect of plasma-induced species on the side chains of the amino acids can be categorized into four types, namely hydroxylation, nitration, dehydrogenation and dimerization. In addition, relative activities of amino acids resulting from plasma treatment come in descending order as follows: sulfur-containing carbon-chain amino acids > aromatic amino acids > five-membered ring amino acids > basic carbon-chain amino acids. Since amino acids are building blocks of proteins vital to the growth and reproduction of bacteria, these results provide an insight into the mechanism of bacterial inactivation by plasma.

Bacterial profile and antibiogram of otitis media among children in yemen

International Nuclear Information System (INIS)

Mohanna, M.A.B.

2016-01-01

Otitis media is a worldwide disease and is higher in developing countries, particularly among the low socioeconomic levels of the society. The aim of the study is to identify the bacterial etiologic agents of otitis media (OM) and their antibiotics sensitivity patterns among children in Specialized Sam Paediatric Centre (SSPC) and Al-Mamoon Diagnostic Medical Centre (AMDC), in Sana'a city. Methods: A cross-sectional study was done in SSPC and AMDC from January to October 2015. A total of 150 patients who had ear pus discharge and clinically diagnosed as OM were included in this study. Samples of ear discharge were collected, bacteriologically tested by standard methods and bacterial strains were identified using biochemical testes. Questionnaire was administered on patients or parents that cover the age, gender and the duration of symptoms. Results: A total of 150 children with OM, their age ranged from below 1-15 years (85 males and 65 females). Children less than 5 years of age were 100 and 50 with age ranged from 6-15 years. Bacterial isolates were Staphylococcus aureus (44%), Pseudomonas aeruginosa (12.67%), Enterococcus species (12.67%), and Streptococcus pneumonia (10%). Bacterial culture revealed that, Staphylococcus aureus sensitivity to cefotaxime and azithromycin was 98%, to amoxicillin-clavulanic acid was 92% and it was 85% to gentamicin. Pseudomonas aeruginosa sensitivity to cefotaxime was 100%, to azithromycin and gentamicin was 98% and it was 80% to cefaclor. Enterococcus sensitivity to amoxicillin-clavulanic acid was 85%, to azithromycin was 80%, and it was 75% to cefotaxime, and gentamicin. Conclusion: The most common microorganism isolated was Staphylococcus aureus followed by Pseudomonas, Enterococcus species, and then Streptococcus pneumonia. The most effective antibiotics were cefotaxime, amoxicillin-clavulanic acid, azithromycin and gentamicin. Therefore, knowledge of antimicrobial susceptibility test is essential for guiding appropriate

Bacterial Profile And Antibiogram Of Otitis Media Among Children In Yemen.

Science.gov (United States)

Bin Mohanna, Mabrook Aidah; Bahannan, Abdurrahman Ali

2016-01-01

Otitis media is a worldwide disease and is higher in developing countries, particularly among the low socioeconomic levels of the society. The aim of the study is to identify the bacterial etiologic agents of otitis media (OM) and their antibiotics sensitivity patterns among children in Specialized Sam Paediatric Centre (SSPC) and Al-Mamoon Diagnostic Medical Centre (AMDC), in Sana'a city. A cross-sectional study was done in SSPC and AMDC from January to October 2015. A total of 150 patients who had ear pus discharge and clinically diagnosed as OM were included in this study. Samples of ear discharge were collected, bacteriologically tested by standard methods and bacterial strains were identified using biochemical testes. Questionnaire was administered on patients or parents that cover the age, gender and the duration of symptoms. A total of 150 children with OM, their age ranged from below 1-15 years (85 males and 65 females). Children less than 5 years of age were 100 and 50 with age ranged from 6-15 years. Bacterial isolates were Staphylococcus aureus (44%), Pseudomonas aeruginosa (12.67%), Enterococcus species (12.67%), and Streptococcus pneumonia (10%). Bacterial culture revealed that, Staphylococcus aureus sensitivity to cefotaxime and azithromycin was 98%, to amoxicillin-clavulanic acid was 92% and it was 85% to gentamicin. Pseudomonas aeruginosa sensitivity to cefotaxime was 100%, to azithromycin and gentamicin was 98% and it was 80% to cefaclor. Enterococcus sensitivity to amoxicillin-clavulanic acid was 85%, to azithromycin was 80%, and it was 75% to cefotaxime, and gentamicin. The most common microorganism isolated was Staphylococcus aureus followed by Pseudomonas, Enterococcus species, and then Streptococcus pneumonia. The most effective antibiotics were cefotaxime, amoxicillin-clavulanic acid, azithromycin and gentamicin. Therefore, knowledge of antimicrobial susceptibility test is essential for guiding appropriate antibacterial therapy.

~ Nigerian VeterinaryJournal ARTIClE-------------------------------------------

African Journals Online (AJOL)

causes damage to cell membrane ..... fatty acid transport by antioxidants evC. &VE) into mitochondria for energy production, ... due to generation of free radicals that could have inhibited the hypothalamic .... like protein, deoxyribonucleic acid and .... B., GELAYE, S. and AMOAH. E.A. (2002). Simulated preslaughter. 1004 ...

HIV-1 in the RNA world: Transcription regulation, miRNAs and antiviral RNAs

NARCIS (Netherlands)

Harwig, A.

2015-01-01

All organisms, from bacteria to human, use three biological molecules that each serve critical functions in the expression of genes in the cell. These are deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and proteins. RNA is synthesized from DNA in a process called transcription. RNA differs from

Fundamental Approaches in Molecular Biology for Communication Sciences and Disorders

Science.gov (United States)

Bartlett, Rebecca S.; Jette, Marie E.; King, Suzanne N.; Schaser, Allison; Thibeault, Susan L.

2012-01-01

Purpose: This contemporary tutorial will introduce general principles of molecular biology, common deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein assays and their relevance in the field of communication sciences and disorders. Method: Over the past 2 decades, knowledge of the molecular pathophysiology of human disease has…

STUDIES ON THE BACTERIOPHAGE OF D'HERELLE : IX. EVIDENCE OF HYDROLYSIS OF BACTERIAL PROTEIN DURING LYSIS.

Science.gov (United States)

Hetler, D M; Bronfenbrenner, J

1928-07-31

1. During the process of lysis by bacteriophage, there is an appreciable increase in the amount of free amino acid present in the culture. 2. The increase of free amino acid is due to hydrolysis of bacterial protein.

Bacterial diversity shift determined by different diets in the gut of the spotted wing fly Drosophila suzukii is primarily reflected on acetic acid bacteria

KAUST Repository

Vacchini, Violetta

2016-11-25

The pivotal role of diet in shaping gut microbiota has been evaluated in different animal models, including insects. Drosophila flies harbour an inconstant microbiota among which acetic acid bacteria (AAB) are important components. Here, we investigated the bacterial and AAB components of the invasive pest Drosophila suzukii microbiota, by studying the same insect population separately grown on fruit-based or non-fruit artificial diet. AAB were highly prevalent in the gut under both diets (90 and 92% infection rates with fruits and artificial diet, respectively). Fluorescent in situ hybridization and recolonization experiments with green fluorescent protein (Gfp)-labelled strains showed AAB capability to massively colonize insect gut. High-throughput sequencing on 16S rRNA gene indicated that the bacterial microbiota of guts fed with the two diets clustered separately. By excluding AAB-related OTUs from the analysis, insect bacterial communities did not cluster separately according to the diet, suggesting that diet-based diversification of the community is primarily reflected on the AAB component of the community. Diet influenced also AAB alpha-diversity, with separate OTU distributions based on diets. High prevalence, localization and massive recolonization, together with AAB clustering behaviour in relation to diet, suggest an AAB role in the D. suzukii gut response to diet modification. This article is protected by copyright. All rights reserved.

Study of a bacterial leaching program for uranium ores by Thiobacillus ferroxidans

International Nuclear Information System (INIS)

Garcia Junior, O.

1989-01-01

The development of a bacterial leaching program for uranium ores is studied. Three basic points are presented: isolation and purification of Thiobacillus ferroxidans, as well Thiobacillus thio oxidans; physiological studies of growth and respiratory metabolism of T. ferroxidans; uranium leaching from two types of ore by T. ferroxidans action, on laboratory, semi pilot and pilot scales. The bacterial leaching studies were carried out in shake flasks, percolation columns (laboratory and semi pilot) and in heap leaching (pilot). The potential of the ores studied in relation to bacterial action, was first showed in shake flask experiments. The production of H 2 S O 4 and Fe 3+ was a result of the bacterial activity on both ore samples containing pyrite (Fe S 2 ). These two bacterial products resulted in a high uranium and molybdenum extraction and a lower sulfuric acid consumption compared to the sterilized treatments. Similar results were obtained in percolation column at the same scale (lab). (author)

Novel approach for the use of dairy industry wastes for bacterial growth media production.

Science.gov (United States)

Kasmi, Mariam; Elleuch, Lobna; Dahmeni, Ameni; Hamdi, Moktar; Trabelsi, Ismail; Snoussi, Mejdi

2018-04-15

This work proposes a novel approach for the reuse and the recovery of dairy wastes valuable components. Thermal coagulation was performed for dairy effluents and the main responsible fraction for the organic matter content (protein and fat) was separated. Dairy curds were prepared for the formulation of bacterial growth media. Protein, sugar, fat and fatty acids contents have been assessed. Samples treated at 100 °C exhibited marked improvement in terms of protein (25-50%) recovery compared to those treated at 80 °C. Fatty acid analysis revealed the presence of unsaturated fatty acids (mainly oleic acid) that are essential to promote Lactobacillus growth. Previously isolated and identified bacterial strains from dairy wastes (Lactobacillus paracasei, Lactobacillus plantarum, Lactococcus lactis and Lactobacillus brevis) were investigated for their ability to grow on the formulated media. All the tested lactic acid bacteria exhibited greater bacterial growth on the formulated media supplemented with glucose only or with both glucose and yeast extract compared to the control media. By reference to the commercial growth medium, the productivity ratio of the supplemented bactofugate (B) and decreaming (D) formulated media exceeded 0.6 for L. paracasei culture. Whereas, the productivity ratio of the supplemented B medium was greater than 1 compared to the control medium for all the tested strains. As for the supplemented D medium, its productivity ratio was greater than 1 compared to the control medium for both L. paracasei and L. plantarum strains. Copyright © 2018 Elsevier Ltd. All rights reserved.

Antiproliferative potential of aqueous leaf extract of Mucuna pruriens ...

African Journals Online (AJOL)

. pruriens and weight determination was employed using standard protocol. Comet assay protocol was employed to determine level of deoxyribonucleic acid (DNA) fragmentation while hematoxylin and eosin were used for histological assay.

Gaseous 3-pentanol primes plant immunity against a bacterial speck pathogen, Pseudomonas syringae pv. tomato via salicylic acid and jasmonic acid-dependent signaling pathways in Arabidopsis.

Science.gov (United States)

Song, Geun C; Choi, Hye K; Ryu, Choong-Min

2015-01-01

3-Pentanol is an active organic compound produced by plants and is a component of emitted insect sex pheromones. A previous study reported that drench application of 3-pentanol elicited plant immunity against microbial pathogens and an insect pest in crop plants. Here, we evaluated whether 3-pentanol and the derivatives 1-pentanol and 2-pentanol induced plant systemic resistance using the in vitro I-plate system. Exposure of Arabidopsis seedlings to 10 μM and 100 nM 3-pentanol evaporate elicited an immune response to Pseudomonas syringae pv. tomato DC3000. We performed quantitative real-time PCR to investigate the 3-pentanol-mediated Arabidopsis immune responses by determining Pathogenesis-Related (PR) gene expression levels associated with defense signaling through salicylic acid (SA), jasmonic acid (JA), and ethylene signaling pathways. The results show that exposure to 3-pentanol and subsequent pathogen challenge upregulated PDF1.2 and PR1 expression. Selected Arabidopsis mutants confirmed that the 3-pentanol-mediated immune response involved SA and JA signaling pathways and the NPR1 gene. Taken together, this study indicates that gaseous 3-pentanol triggers induced resistance in Arabidopsis by priming SA and JA signaling pathways. To our knowledge, this is the first report that a volatile compound of an insect sex pheromone triggers plant systemic resistance against a bacterial pathogen.

Gaseous 3-pentanol primes plant immunity against a bacterial speck pathogen, Pseudomonas syringae pv. tomato via salicylic acid and jasmonic acid-dependent signaling pathways in Arabidopsis

Directory of Open Access Journals (Sweden)

Geun Cheol eSong

2015-10-01

Full Text Available 3-Pentanol is an active organic compound produced by plants and is a component of emitted insect sex pheromones. A previous study reported that drench application of 3-pentanol elicited plant immunity against microbial pathogens and an insect pest in crop plants. Here, we evaluated whether 3-pentanol and the derivatives 1-pentanol and 2-pentanol induced plant systemic resistance using the in vitro I-plate system. Exposure of Arabidopsis seedlings to 10 M and 100 nM 3-pentanol evaporate elicited an immune response to Pseudomonas syringae pv. tomato DC3000. We performed quantitative real-time PCR to investigate the 3-pentanol-mediated Arabidopsis immune responses by determining Pathogenesis-Related (PR gene expression levels associated with defense signaling through SA, JA, and ethylene signaling pathways. The results show that exposure to 3-pentanol and subsequent pathogen challenge upregulated PDF1.2 and PR1 expression. Selected Arabidopsis mutants confirmed that the 3-pentanol-mediated immune response involved salicylic acid (SA and jasmonic acid (JA signaling pathways and the NPR1 gene. Taken together, this study indicates that gaseous 3-pentanol triggers induced resistance in Arabidopsis by priming SA and JA signaling pathways. To our knowledge, this is the first report that a volatile compound of an insect sex pheromone triggers plant systemic resistance against a bacterial pathogen.

Effects of dietary inulin on bacterial growth, short-chain fatty acid production and hepatic lipid metabolism in gnotobiotic mice.

Science.gov (United States)

Weitkunat, Karolin; Schumann, Sara; Petzke, Klaus Jürgen; Blaut, Michael; Loh, Gunnar; Klaus, Susanne

2015-09-01

In literature, contradictory effects of dietary fibers and their fermentation products, short-chain fatty acids (SCFA), are described: On one hand, they increase satiety, but on the other hand, they provide additional energy and promote obesity development. We aimed to answer this paradox by investigating the effects of fermentable and non-fermentable fibers on obesity induced by high-fat diet in gnotobiotic C3H/HeOuJ mice colonized with a simplified human microbiota. Mice were fed a high-fat diet supplemented either with 10% cellulose (non-fermentable) or inulin (fermentable) for 6 weeks. Feeding the inulin diet resulted in an increased diet digestibility and reduced feces energy, compared to the cellulose diet with no differences in food intake, suggesting an increased intestinal energy extraction from inulin. However, we observed no increase in body fat/weight. The additional energy provided by the inulin diet led to an increased bacterial proliferation in this group. Supplementation of inulin resulted further in significantly elevated concentrations of total SCFA in cecum and portal vein plasma, with a reduced cecal acetate:propionate ratio. Hepatic expression of genes involved in lipogenesis (Fasn, Gpam) and fatty acid elongation/desaturation (Scd1, Elovl3, Elovl6, Elovl5, Fads1 and Fads2) were decreased in inulin-fed animals. Accordingly, plasma and liver phospholipid composition were changed between the different feeding groups. Concentrations of omega-3 and odd-chain fatty acids were increased in inulin-fed mice, whereas omega-6 fatty acids were reduced. Taken together, these data indicate that, during this short-term feeding, inulin has mainly positive effects on the lipid metabolism, which could cause beneficial effects during obesity development in long-term studies. Copyright © 2015 Elsevier Inc. All rights reserved.

Bacterial decontamination using ambient pressure nonthermal discharges

Energy Technology Data Exchange (ETDEWEB)

Birmingham, J.G.; Hammerstrom, D.J.

2000-02-01

Atmospheric pressure nonthermal plasmas can efficiently deactivate bacteria in gases, liquids, and on surfaces, as well as can decompose hazardous chemicals. This paper focuses on the changes to bacterial spores and toxic biochemical compounds, such as mycotoxins, after their treatment in ambient pressure discharges. The ability of nonthermal plasmas to decompose toxic chemicals and deactivate hazardous biological materials has been applied to sterilizing medical instruments, ozonating water, and purifying air. In addition, the fast lysis of bacterial spores and other cells has led us to include plasma devices within pathogen detection instruments, where nucleic acids must be accessed. Decontaminating chemical and biological warfare materials from large, high value targets such as building surfaces, after a terrorist attack, are especially challenging. A large area plasma decontamination technology is described.

Detection of Bacterial Endospores in Soil by Terbium Fluorescence

Directory of Open Access Journals (Sweden)

Andrea Brandes Ammann

2011-01-01

Full Text Available Spore formation is a survival mechanism of microorganisms when facing unfavorable environmental conditions resulting in “dormant” states. We investigated the occurrence of bacterial endospores in soils from various locations including grasslands (pasture, meadow, allotment gardens, and forests, as well as fluvial sediments. Bacterial spores are characterized by their high content of dipicolinic acid (DPA. In the presence of terbium, DPA forms a complex showing a distinctive photoluminescence spectrum. DPA was released from soil by microwaving or autoclaving. The addition of aluminium chloride reduced signal quenching by interfering compounds such as phosphate. The highest spore content (up to 109 spores per gram of dry soil was found in grassland soils. Spore content is related to soil type, to soil depth, and to soil carbon-to-nitrogen ratio. Our study might provide a basis for the detection of “hot spots” of bacterial spores in soil.

Increased systemic oxidatively generated DNA and RNA damage in schizophrenia

DEFF Research Database (Denmark)

Jørgensen, Anders; Brødbæk, Kasper; Fink-Jensen, Anders

2013-01-01

such as cardiovascular disease, type 2 diabetes and dementia. We determined the urinary excretion of markers of systemic Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA) oxidation, 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydroguanosine, respectively, in 40 schizophrenia patients and 40 age- and sex...

Bacterial Aggregates Establish at the Edges of Acute Epidermal Wounds

DEFF Research Database (Denmark)

Bay, Lene; Kragh, Kasper N.; Eickhardt, Steffen R.

2018-01-01

for culturing from the wounds and adjacent skin, and the wounds including adjacent skin were excised. Tissue sections were stained with peptide nucleic acid (PNA) fluorescence in situ hybridization (FISH) probes, counterstained by 4′,6-diamidino-2-phenylindole, and evaluated by confocal laser scanning...... microscopy (CLSM). Results: No bacterial aggregates were detected at day 0. At day 4, coagulase-negative staphylococci (CoNS) were the sole bacteria identified by CLSM/PNA-FISH and culturing. CoNS was isolated from 78% of the wound swabs and 48% of the skin swabs. Bacterial aggregates (5–150 μm) were...

Adherence of amino acids functionalized iron oxide nanoparticles on bacterial models E. Coli and B. subtilis

Science.gov (United States)

Trujillo, W.; Zarria, J.; Pino, J.; Menacho, L.; Coca, M.; Bustamante, A.

2018-03-01

Magnetic iron oxides nanoparticles (NPs) functionalized with lysine (Lys) and arginine (Arg) was obtained by following chemical co-precipitation route in basic medium. The synthesis was performed by mixing ferrous chloride (FeCl2•4H2O), ferric chloride (FeCl3•6H2O) and the specific amino acid in a molar ratio of 1: 2: 0.5, respectively. High pH sample was washed several times with distilled water to reach a pH similar to distilled water (Ph=7) after the synthesis process, part of the NPs obtained was dried. Of the measurements of XRD and MS was obtained that the samples are magnetic nanoparticles of maghemite of about 9 nm in diameter. Of the FTIR and zeta potential measures was obtained that the amino acids Lys and Arg were correctly functionalized at magnetic nanoparticles, referred to herein as M@Lys and M@Arg. In order to demonstrate the capture and adhesion of the nanoparticles to the bacteria, scanning electron microscopy (SEM) was performed. The obtained visualization of both bacteria shows that they are coated by the magnetic particles. In addition, M@Lys (B. sutilis) were cultured to verify the inhibition of growth measured by colony forming units (CFU), the concentrations of M@Lys were 1.75x102 g/mL and 0.875x102 g/mL. After the confrontation obtained efficiencies of 75.63% and 98.75% respectively for the third dilution. While for the fourth dilution were 90% and 98.57% respectively were obtained for each concentration of nanoparticles. Hinting that a high efficiency of bacterial capture at very low concentrations of NPs, which gives us a tool to capture nanobiotechnology bacteria in liquid cultures with application to capture them in wastewater. Based on our results we concluded that NPS functionalized with the amino acids Lys and Arg adhere to the bacteria efficiently in low concentrations.

Substantial nutritional contribution of bacterial amino acids to earthworms and enchytraeids: A case study from organic grasslands

DEFF Research Database (Denmark)

Larsen, Thomas; Pollierer, Melanie M.; Holmstrup, Martin

2016-01-01

worms relied equally on bacterial and plant derived EAA. Our study provides answers to some of the long-standing questions in regards to the role of bacteria for earthworm nutrition. While bacterial EAA contribution to anecic worms was relatively modest, less than one-quarter, bacterial contribution...... to endogeic and enchytraeid worms was substantial comprising almost half of their EAA. Our findings are important for understanding how different ecological groups of terrestrial oligochaetes meet nutritional needs and partition food resources....

Direct analysis by time-of-flight secondary ion mass spectrometry reveals action of bacterial laccase-mediator systems on both hardwood and softwood samples.

Science.gov (United States)

Goacher, Robyn E; Braham, Erick J; Michienzi, Courtney L; Flick, Robert M; Yakunin, Alexander F; Master, Emma R

2017-12-29

The modification and degradation of lignin play a vital role in carbon cycling as well as production of biofuels and bioproducts. The possibility of using bacterial laccases for the oxidation of lignin offers a route to utilize existing industrial protein expression techniques. However, bacterial laccases are most frequently studied on small model compounds that do not capture the complexity of lignocellulosic materials. This work studied the action of laccases from Bacillus subtilis and Salmonella typhimurium (EC 1.10.3.2) on ground wood samples from yellow birch (Betula alleghaniensis) and red spruce (Picea rubens). The ability of bacterial laccases to modify wood can be facilitated by small molecule mediators. Herein, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), gallic acid and sinapic acid mediators were tested. Direct analysis of the wood samples was achieved by time-of-flight secondary ion mass spectrometry (ToF-SIMS), a surface sensitive mass spectrometry technique that has characteristic peaks for H, G and S lignin. The action of the bacterial laccases on both wood samples was demonstrated and revealed a strong mediator influence. The ABTS mediator led to delignification, evident in an overall increase of polysaccharide peaks in the residual solid, along with equal loss of G and S-lignin peaks. The gallic acid mediator demonstrated minimal laccase activity. Meanwhile, the sinapic acid mediator altered the S/G peak ratio consistent with mediator attaching to the wood solids. The current investigation demonstrates the action of bacterial laccase-mediator systems directly on woody materials, and the potential of using ToF-SIMS to uncover the fundamental and applied role of bacterial enzymes in lignocellulose conversion. © 2017 Scandinavian Plant Physiology Society.

Role of lipids in bacterial radioresistance

International Nuclear Information System (INIS)

Abushady, M.R.; Fawkia, M.E.; Tawfik, Z.S.

1992-01-01

The radioresistance of three bacterial isolates was determined. S. aureus was the most sensitive one (D 1 0 value 0.14 KGy), B. coagulans was moderate resistant (D 1 0 value 3.3 KGy) and the most resistant one was B.megaterium (D 1 0 value 3.7 KGy). Total lipids and lipid patterns of these bacteria were determined and the role of lipids in radioresistance was investigated. Least amount of total lipids was detected in the most sensitive organism (S. aureus). The increase in the bacterial content of total lipids was concomitant with high degrees of radioresistance. The most resistant organism (B. megaterium was characterized by high content of methyl esters of fatty acids, phosphatidylcholine and phosphatidylethanolamine, followed by appreciable amounts in the moderate resistant (B. coagulans) and the least amounts were detected in the most sensitive organism (S.aureus).6 fig., 3 tab

Relationship among Phosphorus Circulation Activity, Bacterial Biomass, pH, and Mineral Concentration in Agricultural Soil

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Dinesh Adhikari

2017-12-01

Full Text Available Improvement of phosphorus circulation in the soil is necessary to enhance phosphorus availability to plants. Phosphorus circulation activity is an index of soil’s ability to supply soluble phosphorus from organic phosphorus in the soil solution. To understand the relationship among phosphorus circulation activity; bacterial biomass; pH; and Fe, Al, and Ca concentrations (described as mineral concentration in this paper in agricultural soil, 232 soil samples from various agricultural fields were collected and analyzed. A weak relationship between phosphorus circulation activity and bacterial biomass was observed in all soil samples (R2 = 0.25, and this relationship became significantly stronger at near-neutral pH (6.0–7.3; R2 = 0.67. No relationship between phosphorus circulation activity and bacterial biomass was observed at acidic (pH < 6.0 or alkaline (pH > 7.3 pH. A negative correlation between Fe and Al concentrations and phosphorus circulation activity was observed at acidic pH (R2 = 0.72 and 0.73, respectively, as well as for Ca at alkaline pH (R2 = 0.64. Therefore, bacterial biomass, pH, and mineral concentration should be considered together for activation of phosphorus circulation activity in the soil. A relationship model was proposed based on the effects of bacterial biomass and mineral concentration on phosphorus circulation activity. The suitable conditions of bacterial biomass, pH, and mineral concentration for phosphorus circulation activity could be estimated from the relationship model.

Detection of Ca2+-dependent acid phosphatase activity identifies neuronal integrity in damaged rat central nervous system after application of bacterial melanin

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Tigran R Petrosyan

2016-01-01

Full Text Available The study aims to confirm the neuroregenerative effects of bacterial melanin (BM on central nervous system injury using a special staining method based on the detection of Ca2+-dependent acid phosphatase activity. Twenty-four rats were randomly assigned to undergo either unilateral destruction of sensorimotor cortex (group I; n = 12 or unilateral rubrospinal tract transection at the cervical level (C3–4 (group II; n = 12. In each group, six rats were randomly selected after surgery to undergo intramuscular injection of BM solution (BM subgroup and the remaining six rats were intramuscularly injected with saline (saline subgroup. Neurological testing confirmed that BM accelerated the recovery of motor function in rats from both BM and saline subgroups. Two months after surgery, Ca2+-dependent acid phosphatase activity detection in combination with Chilingarian's calcium adenoside triphosphate method revealed that BM stimulated the sprouting of fibers and dilated the capillaries in the brain and spinal cord. These results suggest that BM can promote the recovery of motor function of rats with central nervous system injury; and detection of Ca2+-dependent acid phosphatase activity is a fast and easy method used to study the regeneration-promoting effects of BM on the injured central nervous system.

Modeling bacterial contamination of fuel ethanol fermentation.

Science.gov (United States)

Bischoff, Kenneth M; Liu, Siqing; Leathers, Timothy D; Worthington, Ronald E; Rich, Joseph O

2009-05-01

The emergence of antibiotic-resistant bacteria may limit the effectiveness of antibiotics to treat bacterial contamination in fuel ethanol plants, and therefore, new antibacterial intervention methods and tools to test their application are needed. Using shake-flask cultures of Saccharomyces cerevisiae grown on saccharified corn mash and strains of lactic acid bacteria isolated from a dry-grind ethanol facility, a simple model to simulate bacterial contamination and infection was developed. Challenging the model with 10(8) CFU/mL Lactobacillus fermentum decreased ethanol yield by 27% and increased residual glucose from 6.2 to 45.5 g/L. The magnitude of the effect was proportional to the initial bacterial load, with 10(5) CFU/mL L. fermentum still producing an 8% decrease in ethanol and a 3.2-fold increase in residual glucose. Infection was also dependent on the bacterial species used to challenge the fermentation, as neither L. delbrueckii ATCC 4797 nor L. amylovorus 0315-7B produced a significant decrease in ethanol when inoculated at a density of 10(8) CFU/mL. In the shake-flask model, treatment with 2 microg/mL virginiamycin mitigated the infection when challenged with a susceptible strain of L. fermentum (MIC for virginiamycin model may find application in developing new antibacterial agents and management practices for use in controlling contamination in the fuel ethanol industry. Copyright 2008 Wiley Periodicals, Inc.

Functional role of pyruvate kinase from Lactobacillus bulgaricus in acid tolerance and identification of its transcription factor by bacterial one-hybrid.

Science.gov (United States)

Zhai, Zhengyuan; An, Haoran; Wang, Guohong; Luo, Yunbo; Hao, Yanling

2015-11-19

Lactobacillus delbrueckii subsp. bulgaricus develops acid tolerance response when subjected to acid stress conditions, such as the induction of enzymes associated with carbohydrate metabolism. In this study, pyk gene encoding pyruvate kinase was over-expressed in heterologous host Lactococcus lactis NZ9000, and SDS-PAGE analysis revealed the successful expression of this gene in NZ9000. The survival rate of Pyk-overproducing strain was 45-fold higher than the control under acid stress condition (pH 4.0). In order to determine the transcription factor (TF) which regulates the expression of pyk by bacterial one-hybrid, we constructed a TF library including 65 TFs of L. bulgaricus. Western blotting indicated that TFs in this library could be successfully expressed in host strains. Subsequently, the promoter of pfk-pyk operon in L. bulgaricus was identified by 5'-RACE PCR. The bait plasmid pH3U3-p01 carrying the deletion fragment of pfk-pyk promoter captured catabolite control protein A (CcpA) which could regulate the expression of pyk by binding to a putative catabolite-responsive element (5'-TGTAAGCCCTAACA-3') upstream the -35 region. Real-time qPCR analysis revealed the transcription of pyk was positively regulated by CcpA. This is the first report about identifying the TF of pyk in L. bulgaricus, which will provide new insight into the regulatory network.

Human papilloma virus prevalence in laryngeal squamous cell carcinoma.

Science.gov (United States)

Gungor, A; Cincik, H; Baloglu, H; Cekin, E; Dogru, S; Dursun, E

2007-08-01

To determine the prevalence and type of human papilloma virus deoxyribonucleic acid (DNA) in cases of laryngeal squamous cell carcinoma. We analysed the prevalence of human papilloma virus infection in archived paraffin block specimens taken from 99 cases of laryngeal squamous cell carcinoma between 1990 and 2005, using polymerase chain reaction techniques. Biopsy specimens from five proven verrucous skin lesions were used as positive controls, and peripheral blood samples from five healthy volunteers were used as negative controls. Four test samples were found to have inadequate deoxyribonucleic acid purity and were therefore excluded from the study. Human papilloma virus deoxyribonucleic acid was detected in seven of 95 cases of laryngeal squamous cell carcinoma (7.36 per cent). Human papilloma virus genotyping revealed double human papilloma virus infection in three cases and single human papilloma virus infection in the remaining four cases. The human papilloma virus genotypes detected were 6, 11 and 16 (the latter detected in only one case). In our series, a very low human papilloma virus prevalence was found among laryngeal squamous cell carcinoma cases. The human papilloma virus genotypes detected were mostly 6 and/or 11, and 16 in only one case. To the best of our knowledge, this is the first report of human papilloma virus prevalence in laryngeal squamous cell carcinoma, based on polymerase chain reaction genotyping in a Turkish population.

Fungal Innate Immunity Induced by Bacterial Microbe-Associated Molecular Patterns (MAMPs

Directory of Open Access Journals (Sweden)

Simon Ipcho

2016-06-01

Full Text Available Plants and animals detect bacterial presence through Microbe-Associated Molecular Patterns (MAMPs which induce an innate immune response. The field of fungal–bacterial interaction at the molecular level is still in its infancy and little is known about MAMPs and their detection by fungi. Exposing Fusarium graminearum to bacterial MAMPs led to increased fungal membrane hyperpolarization, a putative defense response, and a range of transcriptional responses. The fungus reacted with a different transcript profile to each of the three tested MAMPs, although a core set of genes related to energy generation, transport, amino acid production, secondary metabolism, and especially iron uptake were detected for all three. Half of the genes related to iron uptake were predicted MirA type transporters that potentially take up bacterial siderophores. These quick responses can be viewed as a preparation for further interactions with beneficial or pathogenic bacteria, and constitute a fungal innate immune response with similarities to those of plants and animals.

Changes in the rumen bacterial microbiome of cattle exposed to ponderosa pine needles.

Science.gov (United States)

Welch, K D; Stonecipher, C A; Gardner, D R; Cook, D; Pfister, J A

2017-05-01

Consumption of ponderosa pine needles, as well as needles and bark from a number of other trees, can cause abortions in cattle. The abortifacient compounds in these trees are labdane resin acids, including isocupressic acid and agathic acid. Previous research has demonstrated that cattle conditioned to pine needles metabolize the labdane resin acids more quickly than naïve cattle. The results from that study indicated that changes had occurred in the rumen of conditioned cattle. Therefore, in this study, the changes that occurred in the rumen bacterial microflora of cattle during exposure to ponderosa pine needles were evaluated. Cattle were dosed with ground pine needles twice daily for 7 d. Rumen samples were collected on d 0, 3, 7, and 14 (7 d after treatment stopped) and ruminal bacterial microbiome analyses were performed. There were 372 different genera of bacteria identified in the rumen samples. Principal coordinate analysis indicated that there was a significant difference in the rumen bacterial composition between the time points. There were 18 genera that increased in abundance from d 0 to d 7. Twenty three genera decreased in abundance from d 0 to d 7. The results from this study demonstrated that exposure of cattle to pine needles caused a clear shift in the rumen microbiome composition. In general, this shift lasted less than 1 wk post exposure, which indicates that any prophylactic treatment to manipulate the ruminal metabolism of the abortifacient compounds in pine needles would need to be continuously administered to maintain the necessary microbial composition in the rumen.

A simple synthesis of 2-keto-3-deoxy-D-erythro-hexonic acid isopropyl ester, a key sugar for the bacterial population living under metallic stress.

Science.gov (United States)

Grison, Claire M; Renard, Brice-Loïc; Grison, Claude

2014-02-01

2-Keto-3-deoxy-D-erythro-hexonic acid (KDG) is the key intermediate metabolite of the Entner Doudoroff (ED) pathway. A simple, efficient and stereoselective synthesis of KDG isopropyl ester is described in five steps from 2,3-O-isopropylidene-D-threitol with an overall yield of 47%. KDG isopropyl ester is studied as an attractive marker of a functional Entner Doudoroff pathway. KDG isopropyl ester is used to promote growth of ammonium producing bacterial strains, showing interesting features in the remediation of heavy-metal polluted soils. Copyright © 2013 Elsevier Inc. All rights reserved.

Characterization of lactic acid bacteria isolated from Algerian arid ...

African Journals Online (AJOL)

Diversity and density of lactic acid bacteria isolated from Algerian raw goats\\' milk in arid zones were studied by determination of morphological, cultural, physiological and biochemical characteristics. 206 lactic acid bacterial strains were isolated, with 115 of them belonging to lactic acid cocci and others to the genus, ...

Discrimination of Spore-Forming Bacilli Using spoIVA

Science.gov (United States)

Venkateswaran, Kasthuri; LaDuc, Myron; Stuecker, Tara

2009-01-01

A method of discriminating between spore-forming and non-spore-forming bacteria is based on a combination of simultaneous sporulation-specific and non-sporulation-specific quantitative polymerase chain reactions (Q-PCRs). The method was invented partly in response to the observation that for the purposes of preventing or reducing biological contamination affecting many human endeavors, ultimately, only the spore-forming portions of bacterial populations are the ones that are problematic (or, at least, more problematic than are the non-spore-forming portions). In some environments, spore-forming bacteria constitute small fractions of the total bacterial populations. The use of sporulation-specific primers in Q-PCR affords the ability to assess the spore-forming fraction of a bacterial population present in an environment of interest. This assessment can provide a more thorough and accurate understanding of the bacterial contamination in the environment, thereby making it possible to focus contamination- testing, contamination-prevention, sterilization, and decontamination resources more economically and efficiently. The method includes the use of sporulation-specific primers in the form of designed, optimized deoxyribonucleic acid (DNA) oligonucleotides specific for the bacterial spoIVA gene (see table). [In "spoIVA," "IV" signifies Roman numeral four and the entire quoted name refers to gene A for the fourth stage of sporulation.] These primers are mixed into a PCR cocktail with a given sample of bacterial cells. A control PCR cocktail into which are mixed universal 16S rRNA primers is also prepared. ["16S rRNA" denotes a ribosomal ribonucleic acid (rRNA) sequence that is common to all organisms.] Following several cycles of heating and cooling according to the PCR protocol to amplify amounts of DNA molecules, the amplification products can be analyzed to determine the types of bacterial cells present within the samples. If the amplification product is strong

Antifungal Activity of Selected Lactic Acid Bacteria and Propionic Acid Bacteria against Dairy-Associated Spoilage Fungi

DEFF Research Database (Denmark)

Aunsbjerg, Stina Dissing

Bacterial cultures of lactic and propionic acid bacteria are widely used in fermented products including dairy products. Spoilage fungi may constitute a quality and safety issue in these products. The antifungal properties of some lactic and propionic acid bacteria make them potential candidates...... defined interaction medium (CDIM) was developed allowing growth of protective Lb. paracasei and P. freudenreichii subsp. shermaniii as well as the spoilage fungi, Penicillium spp., Rhodotorula mucilaginosa and Debaryomyces hansenii isolated from fermented dairy products. Lb. paracasei and P....... freudenreichii subsp. shermanii grew in CDIM and showed antifungal properties similar to those observed in milk-based systems. Most of the antifungal effect of the protective bacterial ferment was lost after removal of cells. This was explained by a marked decrease in diacetyl concentration, which...

Isolation of Biosurfactant–Producing Bacteria with Antimicrobial Activity against Bacterial Pathogens

Directory of Open Access Journals (Sweden)

Siripun Sarin

2011-01-01

Full Text Available The aims of this research were to study biosurfactant producing bacteria isolated from soil and to determine their property and efficiency as biosurfactants in order to inhibit bacterial pathogens. The result showed that there were 8 bacterial isolates out of 136 isolates of the total biosurfactant producing bacteria screened that exhibited the diameter of clear zone more than 1.5 cm. in the oil spreading test. The highest potential of emulsifying activity (%EA24 of 54.4 and the maximum additive concentration, (%MAC of 24.2 was obtained from the fermentation broth of the G7 isolate which the G7 isolate was later identified as Pseudomonas fluorescens. Escherichia coli, Staphylococcus aureus and Psuedomonas aeruginosa were the tested bacterial pathogens that were most sensitive to the acid precipitated biosurfactant obtained from P. fluorescens G7 with the lowest minimum inhibitory concentration (MIC of 41.6 mg/ml and minimum bactericidal concentration (MBC of 41.6 mg/ml compared with the acid precipitated bisurfactants of the other isolates used in the antimicrobial activity test. The type of the separated crude biosurfactant produced by P. fluorescens G7 analyzed later by using the rhamose test, TLC and FT-IR techniques was rhamnolipid.

Microbial ecology of bacterially mediated PCB biodegradation

International Nuclear Information System (INIS)

Pettigrew, C.A. Jr.

1989-01-01

The roles of plasmid mediated and consortia mediated polychlorinated biphenyl (PCB) biodegradation by bacterial populations isolated from PCB contaminated freshwater sediments were investigated. PCB degrading bacteria were isolated by DNA:DNA colony hybridization, batch enrichments, and chemostat enrichment. Analysis of substrate removal and metabolite production were done using chlorinated biphenyl spray plates, reverse phase high pressure liquid chromatography, Cl - detection, and 14 C-labeled substrate mineralization methods. A bacterial consortium, designated LPS10, involved in a concerted metabolic attack on chlorinated biphenyls, was shown to mineralize 4-chlorobiphenyl (4CB) and 4,4'-dichlorobiphenyl (4,4' CB). The LPS10 consortium was isolated by both batch and chemostat enrichment using 4CB and biphenyl (BP) as sole carbon source and was found to have tree bacterial isolates that predominated; these included: Pseudomonas, testosteroni LPS10A which mediated the breakdown of 4CB and 4,4' CB to the putative meta-cleavage product and subsequently to 4-chlorobenzoic acid (4CBA), an isolate tentatively identified as an Arthrobacter sp. LPS10B which mediated 4CBA degradation, and Pseudomonas putida by A LPS10C whose role in the consortium has not been determined

Bacterial prostatitis.

Science.gov (United States)

Gill, Bradley C; Shoskes, Daniel A

2016-02-01

The review provides the infectious disease community with a urologic perspective on bacterial prostatitis. Specifically, the article briefly reviews the categorization of prostatitis by type and provides a distillation of new findings published on bacterial prostatitis over the past year. It also highlights key points from the established literature. Cross-sectional prostate imaging is becoming more common and may lead to more incidental diagnoses of acute bacterial prostatitis. As drug resistance remains problematic in this condition, the reemergence of older antibiotics such as fosfomycin, has proven beneficial. With regard to chronic bacterial prostatitis, no clear clinical risk factors emerged in a large epidemiological study. However, bacterial biofilm formation has been associated with more severe cases. Surgery has a limited role in bacterial prostatitis and should be reserved for draining of a prostatic abscess or the removal of infected prostatic stones. Prostatitis remains a common and bothersome clinical condition. Antibiotic therapy remains the basis of treatment for both acute and chronic bacterial prostatitis. Further research into improving prostatitis treatment is indicated.

Effects of a dual-purpose bacterial inoculant on the fermentation ...

African Journals Online (AJOL)

Effects of a dual-purpose bacterial inoculant on the fermentation characteristics of high-moisture maize silage and dairy cattle performance. ... Inoculation did not affect the nutritive value or the aerobic stability of the maize silage, but increased the neutral detergent and acid detergent fibre fractions of the silage. However ...

Evaluation of free-stall mattress bedding treatments to reduce mastitis bacterial growth

Energy Technology Data Exchange (ETDEWEB)

Kristula, M A; Dou, Z; Toth, J D; Smith, B I; Harvey, N; Sabo, M [University of Penn, Kennett Square, PA (United States)

2008-05-15

Bacterial counts were compared in free-stall mattresses and teat ends exposed to 5 treatments in a factorial study design on 1 dairy farm. Mattresses in five 30-cow groups were subjected to 1 of 5 bedding treatments every other day: 0.5 kg of hydrated limestone, 120 mL of commercial acidic conditioner, 1 kg of coal fly ash, 1 kg of kiln-dried wood shavings, and control (no bedding). Counts of coliforms, Klebsiella spp., Escherichia coli, and Streptococcus spp. were lowest on mattresses bedded with lime. Mattresses bedded with the commercial acidic conditioner had the next lowest counts for coliforms, Klebsiella spp., and Streptococcus spp. Wood shavings and the no-bedding control had the highest counts for coliform and Klebsiella spp. Compared with wood shavings or control, fly ash reduced the counts of coliforms, whereas for the other 3 bacterial groups, the reduction was not always significant. Streptococcus spp. counts were greatest in the control group and did not differ among the shavings and fly ash groups. Teat swab results indicated that hydrated lime was the only bedding treatment that significantly decreased the counts of both coliforms and Klebsiella spp. There were no differences in Streptococcus spp. numbers on the teats between any of the bedding treatments. Bacterial populations grew steadily on mattresses and were generally higher at 36 to 48 h than at 12 to 24 h, whereas bacterial populations on teats grew rapidly by 12 h and then remained constant. Hydrated lime was the only treatment that significantly reduced bacterial counts on both mattresses and teat ends, but it caused some skin irritation.

Plasma concentrations of water-soluble vitamins in metabolic ...

African Journals Online (AJOL)

2012-01-21

Jan 21, 2012 ... histamine, hemoglobin, deoxyribonucleic acid (DNA), and ribonucleic .... workers who had more years of education and were better informed ..... Osuntokun BO, Aladetoyinbo A, Bademosi O. Vitamin B nutrition in the. Nigerian ...

Disaster Doctor From 9/11 to Katrina

Science.gov (United States)

... cytosine—DNA (deoxyribonucleic acid) is life's chemical instruction manual, governing how cells grow, divide, live and die. ... DNA traces that could specifically link victim to identity—had vanished in Katrina's wake. Gone, too, were ...

Effects of aromatic compounds on the production of bacterial nanocellulose by Gluconacetobacter xylinus.

Science.gov (United States)

Zhang, Shuo; Winestrand, Sandra; Guo, Xiang; Chen, Lin; Hong, Feng; Jönsson, Leif J

2014-04-30

Bacterial cellulose (BC) is a polymeric nanostructured fibrillar network produced by certain microorganisms, principally Gluconacetobacter xylinus. BC has a great potential of application in many fields. Lignocellulosic biomass has been investigated as a cost-effective feedstock for BC production through pretreatment and hydrolysis. It is well known that detoxification of lignocellulosic hydrolysates may be required to achieve efficient production of BC. Recent results suggest that phenolic compounds contribute to the inhibition of G. xylinus. However, very little is known about the effect on G. xylinus of specific lignocellulose-derived inhibitors. In this study, the inhibitory effects of four phenolic model compounds (coniferyl aldehyde, ferulic acid, vanillin and 4-hydroxybenzoic acid) on the growth of G. xylinus, the pH of the culture medium, and the production of BC were investigated in detail. The stability of the phenolics in the bacterial cultures was investigated and the main bioconversion products were identified and quantified. Coniferyl aldehyde was the most potent inhibitor, followed by vanillin, ferulic acid, and 4-hydroxybenzoic acid. There was no BC produced even with coniferyl aldehyde concentrations as low as 2 mM. Vanillin displayed a negative effect on the bacteria and when the vanillin concentration was raised to 2.5 mM the volumetric yield of BC decreased to ~40% of that obtained in control medium without inhibitors. The phenolic acids, ferulic acid and 4-hydroxybenzoic acid, showed almost no toxic effects when less than 2.5 mM. The bacterial cultures oxidized coniferyl aldehyde to ferulic acid with a yield of up to 81%. Vanillin was reduced to vanillyl alcohol with a yield of up to 80%. This is the first investigation of the effect of specific phenolics on the production of BC by G. xylinus, and is also the first demonstration of the ability of G. xylinus to convert phenolic compounds. This study gives a better understanding of how

Uric acid disrupts hypochlorous acid production and the bactericidal activity of HL-60 cells.

Science.gov (United States)

Carvalho, Larissa A C; Lopes, João P P B; Kaihami, Gilberto H; Silva, Railmara P; Bruni-Cardoso, Alexandre; Baldini, Regina L; Meotti, Flavia C

2018-06-01

Uric acid is the end product of purine metabolism in humans and is an alternative physiological substrate for myeloperoxidase. Oxidation of uric acid by this enzyme generates uric acid free radical and urate hydroperoxide, a strong oxidant and potentially bactericide agent. In this study, we investigated whether the oxidation of uric acid and production of urate hydroperoxide would affect the killing activity of HL-60 cells differentiated into neutrophil-like cells (dHL-60) against a highly virulent strain (PA14) of the opportunistic pathogen Pseudomonas aeruginosa. While bacterial cell counts decrease due to dHL-60 killing, incubation with uric acid inhibits this activity, also decreasing the release of the inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF- α). In a myeloperoxidase/Cl - /H 2 O 2 cell-free system, uric acid inhibited the production of HOCl and bacterial killing. Fluorescence microscopy showed that uric acid also decreased the levels of HOCl produced by dHL-60 cells, while significantly increased superoxide production. Uric acid did not alter the overall oxidative status of dHL-60 cells as measured by the ratio of reduced (GSH) and oxidized (GSSG) glutathione. Our data show that uric acid impairs the killing activity of dHL-60 cells likely by competing with chloride by myeloperoxidase catalysis, decreasing HOCl production. Despite diminishing HOCl, uric acid probably stimulates the formation of other oxidants, maintaining the overall oxidative status of the cells. Altogether, our results demonstrated that HOCl is, indeed, the main relevant oxidant against bacteria and deviation of myeloperoxidase activity to produce other oxidants hampers dHL-60 killing activity. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Ferrous Iron Oxidation by Thiobacillus ferrooxidans: Inhibition with Benzoic Acid, Sorbic Acid, and Sodium Lauryl Sulfate

OpenAIRE

Onysko, Steven J.; Kleinmann, Robert L. P.; Erickson, Patricia M.

1984-01-01

Benzoic acid, sorbic acid, and sodium lauryl sulfate at low concentrations (5 to 10 mg/liter) each effectively inhibited bacterial oxidation of ferrous iron in batch cultures of Thiobacillus ferrooxidans. The rate of chemical oxidation of ferrous iron in low-pH, sterile batch reactors was not substantially affected at the tested concentrations (5 to 50 mg/liter) of any of the compounds.

Effects of commercial enrichment products on fatty acid components ...

African Journals Online (AJOL)

ajl yemi

2011-10-26

Oct 26, 2011 ... 3050 (ZB) and Spresso (ZC) on fatty acid compositions in rotifers (Brachionus plicatilis) which were intensively ... docosahexaenoic acid (DHA) and the ratio of n–3/n–6 in enriched rotifers groups were higher (p < 0.05). The level of ...... acid profiles and bacterial load in cultured rotifers (Brachionus plicatilis ...

Browse Title Index

African Journals Online (AJOL)

Items 651 - 700 of 11090 ... ... results in physiological and behavioral changes in male mice ... Amplification of deoxyribonucleic acid (DNA) fragment using ... Vol 7, No 6 (2008), An allometric scaling law for understanding mammalian sleep ...

Mercury alters the bacterial community structure and diversity in soil even at concentrations lower than the guideline values.

Science.gov (United States)

Mahbub, Khandaker Rayhan; Subashchandrabose, Suresh Ramraj; Krishnan, Kannan; Naidu, Ravi; Megharaj, Mallavarapu

2017-03-01

This study evaluated the effect of inorganic mercury (Hg) on bacterial community and diversity in different soils. Three soils-neutral, alkaline and acidic-were spiked with six different concentrations of Hg ranging from 0 to 200 mg kg -1 and aged for 90 days. At the end of the ageing period, 18 samples from three different soils were investigated for bacterial community structure and soil physicochemical properties. Illumina MiSeq-based 16s ribosomal RNA (rRNA) amplicon sequencing revealed the alteration in the bacterial community between un-spiked control soils and Hg-spiked soils. Among the bacterial groups, Actinobacteria (22.65%) were the most abundant phyla in all samples followed by Proteobacteria (21.95%), Bacteroidetes (4.15%), Firmicutes (2.9%) and Acidobacteria (2.04%). However, the largest group showing increased abundance with higher Hg doses was the unclassified group (45.86%), followed by Proteobacteria. Mercury had a considerable negative impact on key soil functional bacteria such as ammonium oxidizers and nitrifiers. Canonical correspondence analysis (CCA) indicated that among the measured soil properties, Hg had a major influence on bacterial community structure. Furthermore, nonlinear regression analysis confirmed that Hg significantly decreased soil bacterial alpha diversity in lower organic carbon containing neutral and alkaline soils, whereas in acidic soil with higher organic carbon there was no significant correlation. EC 20 values obtained by a nonlinear regression analysis indicated that Hg significantly decreased soil bacterial diversity in concentrations lower than several guideline values.

Uronic acids in oligosaccharide synthesis

NARCIS (Netherlands)

Bos, Leendert Johannes van den

2007-01-01

This Thesis reports on research aimed at the assembly of acidic and zwitterionic polysaccharides of bacterial origin, using suitably protected 1-thioglycoside residues. Thioglycosides are attractive monosaccharide building blocks because of their high stability towards the diverse reaction

Phenolic biotransformations during conversion of ferulic acid to vanillin by lactic acid bacteria.

Science.gov (United States)

Kaur, Baljinder; Chakraborty, Debkumar; Kumar, Balvir

2013-01-01

Vanillin is widely used as food additive and as a masking agent in various pharmaceutical formulations. Ferulic acid is an important precursor of vanillin that is available in abundance in cell walls of cereals like wheat, corn, and rice. Phenolic biotransformations can occur during growth of lactic acid bacteria (LAB), and their production can be made feasible using specialized LAB strains that have been reported to produce ferulic acid esterases. The present study aimed at screening a panel of LAB isolates for their ability to release phenolics from agrowaste materials like rice bran and their biotransformation to industrially important compounds such as ferulic acid, 4-ethyl phenol, vanillic acid, vanillin, and vanillyl alcohol. Bacterial isolates were evaluated using ferulic acid esterase, ferulic acid decarboxylase, and vanillin dehydrogenase assays. This work highlights the importance of lactic acid bacteria in phenolic biotransformations for the development of food grade flavours and additives.

Phenolic Biotransformations during Conversion of Ferulic Acid to Vanillin by Lactic Acid Bacteria

Science.gov (United States)

Kaur, Baljinder; Kumar, Balvir

2013-01-01

Vanillin is widely used as food additive and as a masking agent in various pharmaceutical formulations. Ferulic acid is an important precursor of vanillin that is available in abundance in cell walls of cereals like wheat, corn, and rice. Phenolic biotransformations can occur during growth of lactic acid bacteria (LAB), and their production can be made feasible using specialized LAB strains that have been reported to produce ferulic acid esterases. The present study aimed at screening a panel of LAB isolates for their ability to release phenolics from agrowaste materials like rice bran and their biotransformation to industrially important compounds such as ferulic acid, 4-ethyl phenol, vanillic acid, vanillin, and vanillyl alcohol. Bacterial isolates were evaluated using ferulic acid esterase, ferulic acid decarboxylase, and vanillin dehydrogenase assays. This work highlights the importance of lactic acid bacteria in phenolic biotransformations for the development of food grade flavours and additives. PMID:24066293

Effect of mercuric chloride on cellular morphology and acid phosphatase of tissue culture cells cultivated in suspension

Energy Technology Data Exchange (ETDEWEB)

Li, M F; Traxler, G S

1974-01-01

Cells exposed to HgCl/sub 2/ (0.5 mg/liter) increased dramatically in size and stained poorly with May-Grunwald Giemsa stain and exhibited incompleteness in cell division. When the cell DNA was stained by the Feulgen technique, many multinucleated cells were apparent in the cultures treated with HgCl/sub 2/. Additionally, enlargement and alteration of the nucleoli were evident. Electron-micrographs of the experimental cells revealed that microvilli, ribosomes, mitochondria, and endoplasmic reticula were abundant in the control cells, but in contrast a scarcity of these organelles was observed together with notable cytoplasmic vacuolation in the HgCl/sub 2/-treated cells. In addition the nucleolini of the treated cells were enlarged and had begun to fuse, producing a mulberry appearance. Electronmicroscopic detection of acid phosphatase activity in the cells indicated that the periplasmic enzyme activity was present in control cells, but not in the cells exposed to HgCl/sub 2/. The possible reaction of Hg/sup + +/ with deoxyribonucleic acid and disulfides is discussed with respect to the observed cytopathic effect and impaired enzyme activity. 10 references, 5 figures.

Bacterial Adhesion & Blocking Bacterial Adhesion

DEFF Research Database (Denmark)

Vejborg, Rebecca Munk

2008-01-01

, which influence the transition from a planktonic lifestyle to a sessile lifestyle, have been studied. Protein conditioning film formation was found to influence bacterial adhesion and subsequent biofilm formation considerable, and an aqueous extract of fish muscle tissue was shown to significantly...... tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... is the first committing step in biofilm formation, and has therefore been intensely scrutinized. Much however, still remains elusive. Bacterial adhesion is a highly complex process, which is influenced by a variety of factors. In this thesis, a range of physico-chemical, molecular and environmental parameters...

Effects of carbon dioxide on metabolite production and bacterial communities during kimchi fermentation.

Science.gov (United States)

Park, Doo Hyun

2018-04-24

Bacterial communities and metabolites in kimchi fermented under conventional conditions (CC) compared to CO 2 -rich environments (CO 2 ) were analyzed. After a 20-day fermentation, lactic and acetic acid productions were 54 and 69 mM under CC, and 19 and 12 mM under CO 2 , respectively. The final pH of kimchi fermented under CC (CC-fermenting) and CO 2 (CO 2 -fermenting) were 4.1 and 4.7, respectively. For bacterial communities, OTU and Chao1 indices were both 35 in fresh kimchi, 10 and 15 in CC-fermenting kimchi, and 8 and 24 in CO 2 -fermenting kimchi, respectively. Shannon and Simpson indices were 3.47 and 0.93 in fresh kimchi, 1.87-0.06 and 0.46-0.01 in CC-fermenting kimchi, and 1.65-0.44 and 0.63-0.12 in CO 2 -fermenting kimchi, respectively. Non-lactic acid bacteria were eliminated in fermenting kimchi after 12 days under CC and 6 days under CO 2 . I conclude that carbon dioxide can alter bacterial communities, reduce metabolite production, and improve fermented kimchi quality.

Ferrous Iron Oxidation by Thiobacillus ferrooxidans: Inhibition with Benzoic Acid, Sorbic Acid, and Sodium Lauryl Sulfate

Science.gov (United States)

Onysko, Steven J.; Kleinmann, Robert L. P.; Erickson, Patricia M.

1984-01-01

Benzoic acid, sorbic acid, and sodium lauryl sulfate at low concentrations (5 to 10 mg/liter) each effectively inhibited bacterial oxidation of ferrous iron in batch cultures of Thiobacillus ferrooxidans. The rate of chemical oxidation of ferrous iron in low-pH, sterile batch reactors was not substantially affected at the tested concentrations (5 to 50 mg/liter) of any of the compounds. PMID:16346592

The role of bacterial antizyme: From an inhibitory protein to AtoC transcriptional regulator

Directory of Open Access Journals (Sweden)

Kyriakidis Dimitrios A

2004-06-01

Full Text Available Abstract This review considers the role of bacterial antizyme in the regulation of polyamine biosynthesis and gives new perspectives on the involvement of antizyme in other significant cellular mechanisms. Antizyme is a protein molecule induced by the end product of the enzymic reaction that it inhibits, in a non-competitive manner. The bacterial ornithine decarboxylase is regulated by nucleotides, phosphorylation and antizyme. The inhibition of ornithine decarboxylase by antizyme can be relieved to different degrees by DNA or by a variety of synthetic nucleic acid polymers, attributed to a specific interaction between nucleic acid and antizyme. Recently, this interplay between bacterial antizyme and nucleic acid was determined by discerning an additional function to antizyme that proved to be the atoC gene product, encoding the response regulator of the bacterial two-component system AtoS-AtoC. The gene located just upstream of atoC encodes the sensor kinase, named AtoS, that modulates AtoC activity. AtoC regulates expression of atoDAEB operon which is involved in short-chain fatty acid metabolism. Antizyme is thus referred to as AtoC, functioning both as a post-translational and transcriptional regulator. Also, the AtoS-AtoC signal transduction system in E. coli has a positive regulatory role on poly-(R-3-hydroxybutyrate biosynthesis. The properties and gene structural similarities of antizymes from different organisms were compared. It was revealed that conserved domains are present mostly in the C-domain of all antizymes. BLAST analysis of the E. coli antizyme protein (AtoC showed similarities around 69–58% among proteobacteria, g-proteobacteria, enterobacteria and the thermophilic bacterium Thermus thermophilus. A working hypothesis is proposed for the metabolic role of antizyme (AtoC describing the significant biological implications of this protein molecule. Whether antizymes exist to other enzymes in different tissues, meeting the

Biodiversity of bacterial ecosystems in traditional Egyptian Domiati cheese.

Science.gov (United States)

El-Baradei, Gaber; Delacroix-Buchet, Agnès; Ogier, Jean-Claude

2007-02-01

Bacterial biodiversity occurring in traditional Egyptian soft Domiati cheese was studied by PCR-temporal temperature gel electrophoresis (TTGE) and PCR-denaturing gradient gel electrophoresis (DGGE). Bands were identified using a reference species database (J.-C. Ogier et al., Appl. Environ. Microbiol. 70:5628-5643, 2004); de novo bands having nonidentified migration patterns were identified by DNA sequencing. Results reveal a novel bacterial profile and extensive bacterial biodiversity in Domiati cheeses, as reflected by the numerous bands present in TTGE and DGGE patterns. The dominant lactic acid bacteria (LAB) identified were as follows: Leuconostoc mesenteroides, Lactococcus garvieae, Aerococcus viridans, Lactobacillus versmoldensis, Pediococcus inopinatus, and Lactococcus lactis. Frequent non-LAB species included numerous coagulase-negative staphylococci, Vibrio spp., Kocuria rhizophila, Kocuria kristinae, Kocuria halotolerans, Arthrobacter spp./Brachybacterium tyrofermentans. This is the first time that the majority of these species has been identified in Domiati cheese. Nearly all the dominant and frequent bacterial species are salt tolerant, and several correspond to known marine bacteria. As Domiati cheese contains 5.4 to 9.5% NaCl, we suggest that these bacteria are likely to have an important role in the ripening process. This first systematic study of the microbial composition of Domiati cheeses reveals great biodiversity and evokes a role for marine bacteria in determining cheese type.

Biodiversity of Bacterial Ecosystems in Traditional Egyptian Domiati Cheese▿

Science.gov (United States)

El-Baradei, Gaber; Delacroix-Buchet, Agnès; Ogier, Jean-Claude

2007-01-01

Bacterial biodiversity occurring in traditional Egyptian soft Domiati cheese was studied by PCR-temporal temperature gel electrophoresis (TTGE) and PCR-denaturing gradient gel electrophoresis (DGGE). Bands were identified using a reference species database (J.-C. Ogier et al., Appl. Environ. Microbiol. 70:5628-5643, 2004); de novo bands having nonidentified migration patterns were identified by DNA sequencing. Results reveal a novel bacterial profile and extensive bacterial biodiversity in Domiati cheeses, as reflected by the numerous bands present in TTGE and DGGE patterns. The dominant lactic acid bacteria (LAB) identified were as follows: Leuconostoc mesenteroides, Lactococcus garvieae, Aerococcus viridans, Lactobacillus versmoldensis, Pediococcus inopinatus, and Lactococcus lactis. Frequent non-LAB species included numerous coagulase-negative staphylococci, Vibrio spp., Kocuria rhizophila, Kocuria kristinae, Kocuria halotolerans, Arthrobacter spp./Brachybacterium tyrofermentans. This is the first time that the majority of these species has been identified in Domiati cheese. Nearly all the dominant and frequent bacterial species are salt tolerant, and several correspond to known marine bacteria. As Domiati cheese contains 5.4 to 9.5% NaCl, we suggest that these bacteria are likely to have an important role in the ripening process. This first systematic study of the microbial composition of Domiati cheeses reveals great biodiversity and evokes a role for marine bacteria in determining cheese type. PMID:17189434

Focal Targeting of the Bacterial Envelope by Antimicrobial Peptides

Directory of Open Access Journals (Sweden)

Rafi eRashid

2016-06-01

Full Text Available Antimicrobial peptides (AMPs are utilized by both eukaryotic and prokaryotic organisms. AMPs such as the human beta defensins, human neutrophil peptides, human cathelicidin, and many bacterial bacteriocins are cationic and capable of binding to anionic regions of the bacterial surface. Cationic AMPs (CAMPs target anionic lipids (e.g. phosphatidylglycerol (PG and cardiolipins (CL in the cell membrane and anionic components (e.g. lipopolysaccharide (LPS and lipoteichoic acid (LTA of the cell envelope. Bacteria have evolved mechanisms to modify these same targets in order to resist CAMP killing, e.g. lysinylation of PG to yield cationic lysyl-PG and alanylation of LTA. Since CAMPs offer a promising therapeutic alternative to conventional antibiotics, which are becoming less effective due to rapidly emerging antibiotic resistance, there is a strong need to improve our understanding about the AMP mechanism of action. Recent literature suggests that AMPs often interact with the bacterial cell envelope at discrete foci. Here we review recent AMP literature, with an emphasis on focal interactions with bacteria, including (1 CAMP disruption mechanisms, (2 delocalization of membrane proteins and lipids by CAMPs, and (3 CAMP sensing systems and resistance mechanisms. We conclude with new approaches for studying the bacterial membrane, e.g., lipidomics, high resolution imaging and non-detergent-based membrane domain extraction.

Detoxification of mercury pollutant leached from spent fluorescent lamps using bacterial strains.

Science.gov (United States)

Al-Ghouti, Mohammad A; Abuqaoud, Reem H; Abu-Dieyeh, Mohammed H

2016-03-01

The spent fluorescent lamps (SFLs) are being classified as a hazardous waste due to having mercury as one of its main components. Mercury is considered the second most toxic heavy metal (arsenic is the first) with harmful effects on animal nervous system as it causes different neurological disorders. In this research, the mercury from phosphor powder was leached, then bioremediated using bacterial strains isolated from Qatari environment. Leaching of mercury was carried out with nitric and hydrochloric acid solutions using two approaches: leaching at ambient conditions and microwave-assisted leaching. The results obtained from this research showed that microwave-assisted leaching method was significantly better in leaching mercury than the acid leaching where the mercury leaching efficiency reached 76.4%. For mercury bio-uptake, twenty bacterial strains (previously isolated and purified from petroleum oil contaminated soils) were sub-cultured on Luria Bertani (LB) plates with mercury chloride to check the bacterial tolerance to mercury. Seven of these twenty strains showed a degree of tolerance to mercury. The bio-uptake capacities of the promising strains were investigated using the mercury leached from the fluorescent lamps. Three of the strains (Enterobacter helveticus, Citrobacter amalonaticus, and Cronobacter muytjensii) showed bio-uptake efficiency ranged from 28.8% to 63.6%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis of arborane triterpenols by a bacterial oxidosqualene cyclase

Science.gov (United States)

Banta, Amy B.; Wei, Jeremy H.; Gill, Clare C. C.; Giner, José-Luis; Welander, Paula V.

2017-01-01

Cyclic triterpenoids are a broad class of polycyclic lipids produced by bacteria and eukaryotes. They are biologically relevant for their roles in cellular physiology, including membrane structure and function, and biochemically relevant for their exquisite enzymatic cyclization mechanism. Cyclic triterpenoids are also geobiologically significant as they are readily preserved in sediments and are used as biomarkers for ancient life throughout Earth's history. Isoarborinol is one such triterpenoid whose only known biological sources are certain angiosperms and whose diagenetic derivatives (arboranes) are often used as indicators of terrestrial input into aquatic environments. However, the occurrence of arborane biomarkers in Permian and Triassic sediments, which predates the accepted origin of angiosperms, suggests that microbial sources of these lipids may also exist. In this study, we identify two isoarborinol-like lipids, eudoraenol and adriaticol, produced by the aerobic marine heterotrophic bacterium Eudoraea adriatica. Phylogenetic analysis demonstrates that the E. adriatica eudoraenol synthase is an oxidosqualene cyclase homologous to bacterial lanosterol synthases and distinct from plant triterpenoid synthases. Using an Escherichia coli heterologous sterol expression system, we demonstrate that substitution of four amino acid residues in a bacterial lanosterol synthase enabled synthesis of pentacyclic arborinols in addition to tetracyclic sterols. This variant provides valuable mechanistic insight into triterpenoid synthesis and reveals diagnostic amino acid residues to differentiate between sterol and arborinol synthases in genomic and metagenomic datasets. Our data suggest that there may be additional bacterial arborinol producers in marine and freshwater environments that could expand our understanding of these geologically informative lipids.

Practical application of immunofluorescence for the detection of bacterial contaminants during vinification

Directory of Open Access Journals (Sweden)

Marielle Bouix

1997-03-01

Full Text Available This study presents a rapid and specific microscopie technique for detecting and identifying populations of lactic acid bacteria in musts, wines, and inoculum starter cultures. Through the use of fluorescent antibodies, this procedure can be performed in less than two hours, and it is effective with Leuconostoc, Pediococcus and Lactobacillus concentrations as small as 102 cells/ml. Implementation of this technique will assist winemakers in controlling malolactic fermentations and in preventing lactic acid bacterial spoilage.

In vivo metabolism of 2,2'-diaminopimelic acid from gram-positive and gram-negative bacterial cells by ruminal microorganisms and ruminants and its use as a marker of bacterial biomass

International Nuclear Information System (INIS)

Masson, H.A.; Denholm, A.M.; Ling, J.R.

1991-01-01

Cells of Bacillus megaterium GW1 and Escherichia coli W7-M5 were specifically radiolabeled with 2,2'-diamino [G- 3 H] pimelic acid ([ 3 H]DAP) as models of gram-positive and gram-negative bacteria, respectively. Two experiments were conducted to study the in vivo metabolism of 2,2'-diaminopimelic acid (DAP) in sheep. In experiment 1, cells of [ 3 H]DAP-labeled B. megaterium GW1 were infused into the rumen of one sheep and the radiolabel was traced within microbial samples, digesta, and the whole animal. Bacterially bound [ 3 H]DAP was extensively metabolized, primarily (up to 70% after 8 h) via decarboxylation to [ 3 H]lysine by both ruminal protozoa and ruminal bacteria. Recovery of infused radiolabel in urine and feces was low (42% after 96 h) and perhaps indicative of further metabolism by the host animal. In experiment 2, [ 3 H]DAP-labeled B. megaterium GW1 was infused into the rumens of three sheep and [ 3 H]DAP-labeled E. coli W7-W5 was infused into the rumen of another sheep. The radioactivity contents of these mutant bacteria were insufficient to use as tracers, but the metabolism of DAP was monitored in the total, free, and peptidyl forms. Free DAP, as a proportion of total DPA in duodenal digesta, varied from 0 to 9.5%, whereas peptidyl DAP accounted for 8.3 to 99.2%

Kinetics of membrane damage to high (HNA) and low (LNA) nucleic acid bacterial clusters in drinking water by ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate.

Science.gov (United States)

Ramseier, Maaike K; von Gunten, Urs; Freihofer, Pietro; Hammes, Frederik

2011-01-01

Drinking water was treated with ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate to investigate the kinetics of membrane damage of native drinking water bacterial cells. Membrane damage was measured by flow cytometry using a combination of SYBR Green I and propidium iodide (SGI+PI) staining as indicator for cells with permeabilized membranes and SGI alone to measure total cell concentration. SGI+PI staining revealed that the cells were permeabilized upon relatively low oxidant exposures of all tested oxidants without a detectable lag phase. However, only ozonation resulted in a decrease of the total cell concentrations for the investigated reaction times. Rate constants for the membrane damage reaction varied over seven orders of magnitude in the following order: ozone > chlorine > chlorine dioxide ≈ ferrate > permanganate > chloramine. The rate constants were compared to literature data and were in general smaller than previously measured rate constants. This confirmed that membrane integrity is a conservative and therefore safe parameter for disinfection control. Interestingly, the cell membranes of high nucleic acid (HNA) content bacteria were damaged much faster than those of low nucleic acid (LNA) content bacteria during treatment with chlorine dioxide and permanganate. However, only small differences were observed during treatment with chlorine and chloramine, and no difference was observed for ferrate treatment. Based on the different reactivity of these oxidants it was suggested that HNA and LNA bacterial cell membranes have a different chemical constitution. Copyright © 2010 Elsevier Ltd. All rights reserved.

Exploration on trickle leaching of uranium ore by refreshed liquor of bacterial oxidation

International Nuclear Information System (INIS)

Chen Shian; Huang Xiangfu; Fan Baotuan

1995-01-01

The paper describes the adaptation of the domesticated thiobacillus ferroxidans to the trickle leaching conditions of uranium ore. When the bacterial leaching liquor through multiple cycles of oxidation and regeneration was used to return to the trickle leaching, the following results were obtained: the extraction rate was more than 95%, the acid consumption was saved by 30%, and the consumed 2.0% pyrolusite (MnO 2 40%) was eliminated. The following problems are discussed: the basic principle, process and some factors influencing the process of the trickle leaching of uranium ore using regenerated liquor of bacterial oxidation, counter-current trickle leaching mode, oxidation and regeneration techniques of bacterial leaching liquor and other technological problems on the process of uranium extraction by thiobacillus ferroxidans

Bacteriocins and lactic acid bacteria - a minireview | Savadogo ...

African Journals Online (AJOL)

Fermentation of various foods by lactic acid bacteria (LAB) is one of the oldest forms of biopreservation practised by mankind. Bacterial antagonism has been recognized for over a century but in recent years this phenomenon has received more scientific attention, particulary in the use of various strains of lactic acid bacteria.

Quinacrine enhances carmustine therapy of experimental rat glioma.

Science.gov (United States)

Reyes, S; Herrera, L A; Ostrosky, P; Sotelo, J

2001-10-01

The high rate of mutagenesis in malignant cells has been considered to be a primary factor in the appearance of chemotherapy-resistant cell clones in glioblastomas. Quinacrine binds strongly to deoxyribonucleic acid, preventing mutagenesis. We investigated whether quinacrine could improve carmustine therapy in C6 cell cultures and in C6 malignant gliomas implanted subcutaneously into Wistar rats. A potential chemopreventive effect of quinacrine on acquired resistance to carmustine therapy was studied in vitro and in vivo. Deoxyribonucleic acid damage was measured in cultured C6 cells by using the micronucleus test. Wistar rats with subcutaneously implanted C6 gliomas were treated with carmustine, quinacrine, or carmustine plus quinacrine, using pharmacological schemes similar to those used for human patients. The addition of quinacrine to cultured C6 cells did not modify carmustine-induced cytotoxicity; however, the deoxyribonucleic acid damage in surviving cells was minor, as indicated by the frequency of micronucleated cells. The surviving cells continued to be susceptible to a second exposure to carmustine, in contrast to non-quinacrine-treated control cells, which developed resistance to carmustine in a subsequent exposure (P < 0.05). The rate of tumor remission was higher for glioma-bearing rats treated with quinacrine plus carmustine, compared with rats treated with carmustine alone (P < 0.01). The addition of quinacrine to carmustine therapy increases the antineoplastic effect of the carmustine therapy. Our results suggest that chemical inhibition of mutagenesis in malignant glial cells during chemotherapy prevents the appearance of resistant clones.

Phenolic Biotransformations during Conversion of Ferulic Acid to Vanillin by Lactic Acid Bacteria

Directory of Open Access Journals (Sweden)

Baljinder Kaur

2013-01-01

Full Text Available Vanillin is widely used as food additive and as a masking agent in various pharmaceutical formulations. Ferulic acid is an important precursor of vanillin that is available in abundance in cell walls of cereals like wheat, corn, and rice. Phenolic biotransformations can occur during growth of lactic acid bacteria (LAB, and their production can be made feasible using specialized LAB strains that have been reported to produce ferulic acid esterases. The present study aimed at screening a panel of LAB isolates for their ability to release phenolics from agrowaste materials like rice bran and their biotransformation to industrially important compounds such as ferulic acid, 4-ethyl phenol, vanillic acid, vanillin, and vanillyl alcohol. Bacterial isolates were evaluated using ferulic acid esterase, ferulic acid decarboxylase, and vanillin dehydrogenase assays. This work highlights the importance of lactic acid bacteria in phenolic biotransformations for the development of food grade flavours and additives.

Comparison of four species-delimitation methods applied to a DNA barcode data set of insect larvae for use in routine bioassessment for use in routine bioassessment

Science.gov (United States)

Species delimitation (grouping individuals into distinct taxonomic groups) is an essential part of evolutionary, conservation, and molecular ecology. Deoxyribonucleic acid (DNA) barcodes, short fragments of the cytochrome c oxidase subunit I (COI) gene, are being used in environm...

Fulltext PDF

Indian Academy of Sciences (India)

Unknown

deoxyribonucleic acid. M GOPALa*, M S ... base pairs of DNA and interference with normal functioning of the enzyme topo- isomerase II which ... Data from the fluorescence titrations were used to determine the binding constant of. MPTQ with ...

Toxicity of nalidixic acid on candida albicans, Saccharomyces cerevisiae, and Kluyveromyces lactis.

Science.gov (United States)

Sobieski, R J; Brewer, A R

1976-03-01

The antibacterial drug nalidixic acid (Nal) can suppress the growth of Candida albicans at levels of the drug normally found in urine. Growth suppression increases as drug levels are increased, and Nal also causes a similar proportional inhibition of the synthesis of all cellular macromolecules. However, growth temperature (25 versus 37 C) and the divalent cations Mg(2+) and Mn(2+) can increase C. albicans resistance to Nal. Also, nitrogen depletion of Candida shows that Nal-treated and untreated cells exhibit no difference in leucine uptake during readaptation to nitrogen. In Nal-treated, nitrogen-starved cells, ribonucleic acid and deoxyribonucleic acid (DNA) biosynthesis are less affected than in unstarved Nal-treated cells, but of the two nucleic acids DNA synthesis is the most affected. Nal-resistant strains of C. albicans exhibit a slight toxicity for macromolecular synthesis. Nal treatment of a synchronized population of Saccharomyces cerevisiae results in an increase in the culture mean doubling time of, at most, 20%, but Nal causes the loss of synchronous cell division. With a synchronized population of Kluyveromyces lactis, Nal causes an increase in the mean doubling time of upwards of 300%, with synchrony of cell division being maintained. It is known that S. cerevisiae asynchronously synthesizes mitochondrial DNA during the cell cycle, whereas with K. lactis it is synchronous. Thus, with C. albicans Nal toxicity is dependent both on the dose and the physiological state of the cell. Furthermore, Nal inhibits growth of yeast with synchronous mitochondrial DNA synthesis more adversely than yeast with asynchronous mitochondrial DNA synthesis.

Efficacy of Poly-Lactic-Co-Glycolic Acid Micro- and Nanoparticles of Ciprofloxacin Against Bacterial Biofilms.

Science.gov (United States)

Thomas, Nicky; Thorn, Chelsea; Richter, Katharina; Thierry, Benjamin; Prestidge, Clive

2016-10-01

Bacterial biofilms are associated with a number of recurring infectious diseases and are a major cause for antibiotic resistance. Despite the broad use of polymeric microparticles and nanoparticles in biomedical research, it is not clear which particle size is more effective against biofilms. The purpose of this study was to evaluate the efficacy of sustained release poly-lactic-co-glycolic acid (PLGA) micro- and nanoparticles containing ciprofloxacin against biofilms of Staphylococcus aureus and Pseudomonas aeruginosa. The PLGA particles were prepared by the double emulsion solvent evaporation method. The resulting microparticles (12 μm) and nanoparticles (300 nm) contained drug loads of 7.3% and 4.5% (wt/wt) ciprofloxacin, respectively. Drug release was complete within 1 week following comparable release profiles for both particle sizes. Micro- and nanoparticles demonstrated a similar in vitro antibiofilm performance against mature P aeruginosa and S aureus with marked differences between the 2 strains. The sustained release of ciprofloxacin from micro- and nanoparticles over 6 days was equally effective as the continuous treatment with ciprofloxacin solution over the same period resulting in the eradication of culturable S aureus suggesting that reformulation of ciprofloxacin as sustained release PLGA micro- and nanoparticles might be valuable formulation approaches for the treatment of biofilms. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Functional microdomains in bacterial membranes.

Science.gov (United States)

López, Daniel; Kolter, Roberto

2010-09-01

The membranes of eukaryotic cells harbor microdomains known as lipid rafts that contain a variety of signaling and transport proteins. Here we show that bacterial membranes contain microdomains functionally similar to those of eukaryotic cells. These membrane microdomains from diverse bacteria harbor homologs of Flotillin-1, a eukaryotic protein found exclusively in lipid rafts, along with proteins involved in signaling and transport. Inhibition of lipid raft formation through the action of zaragozic acid--a known inhibitor of squalene synthases--impaired biofilm formation and protein secretion but not cell viability. The orchestration of physiological processes in microdomains may be a more widespread feature of membranes than previously appreciated.

Features of the bronchial bacterial microbiome associated with atopy, asthma, and responsiveness to inhaled corticosteroid treatment.

Science.gov (United States)

Durack, Juliana; Lynch, Susan V; Nariya, Snehal; Bhakta, Nirav R; Beigelman, Avraham; Castro, Mario; Dyer, Anne-Marie; Israel, Elliot; Kraft, Monica; Martin, Richard J; Mauger, David T; Rosenberg, Sharon R; Sharp-King, Tonya; White, Steven R; Woodruff, Prescott G; Avila, Pedro C; Denlinger, Loren C; Holguin, Fernando; Lazarus, Stephen C; Lugogo, Njira; Moore, Wendy C; Peters, Stephen P; Que, Loretta; Smith, Lewis J; Sorkness, Christine A; Wechsler, Michael E; Wenzel, Sally E; Boushey, Homer A; Huang, Yvonne J

2017-07-01

Compositional differences in the bronchial bacterial microbiota have been associated with asthma, but it remains unclear whether the findings are attributable to asthma, to aeroallergen sensitization, or to inhaled corticosteroid treatment. We sought to compare the bronchial bacterial microbiota in adults with steroid-naive atopic asthma, subjects with atopy but no asthma, and nonatopic healthy control subjects and to determine relationships of the bronchial microbiota to phenotypic features of asthma. Bacterial communities in protected bronchial brushings from 42 atopic asthmatic subjects, 21 subjects with atopy but no asthma, and 21 healthy control subjects were profiled by using 16S rRNA gene sequencing. Bacterial composition and community-level functions inferred from sequence profiles were analyzed for between-group differences. Associations with clinical and inflammatory variables were examined, including markers of type 2-related inflammation and change in airway hyperresponsiveness after 6 weeks of fluticasone treatment. The bronchial microbiome differed significantly among the 3 groups. Asthmatic subjects were uniquely enriched in members of the Haemophilus, Neisseria, Fusobacterium, and Porphyromonas species and the Sphingomonodaceae family and depleted in members of the Mogibacteriaceae family and Lactobacillales order. Asthma-associated differences in predicted bacterial functions included involvement of amino acid and short-chain fatty acid metabolism pathways. Subjects with type 2-high asthma harbored significantly lower bronchial bacterial burden. Distinct changes in specific microbiota members were seen after fluticasone treatment. Steroid responsiveness was linked to differences in baseline compositional and functional features of the bacterial microbiome. Even in subjects with mild steroid-naive asthma, differences in the bronchial microbiome are associated with immunologic and clinical features of the disease. The specific differences identified

Electrostatic stiffening and induced persistence length for coassembled molecular bottlebrushes

NARCIS (Netherlands)

Storm, Ingeborg M.; Stuart, Martien A.C.; Vries, de Renko; Leermakers, Frans A.M.

2018-01-01

A self-consistent field analysis for tunable contributions to the persistence length of isolated semiflexible polymer chains including electrostatically driven coassembled deoxyribonucleic acid (DNA) bottlebrushes is presented. When a chain is charged, i.e., for polyelectrolytes, there is, in

Promotion and inhibition of mutation in pathogens

Directory of Open Access Journals (Sweden)

Maurice Samuel Devaraj

2014-03-01

Findings from this research may be used to prevent development of drug resistance, whether epigenetic or arising due to deoxyribonucleic acid (DNA modification, in several pathogens, especially Mycobacterium tuberculosis through the co-administration of adenosine along with antibiotic treatment.

Microbiological analysis of common preservatives used in food items and demonstration of their in vitro anti-bacterial activity

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Tohora Sultana

2014-12-01

Full Text Available Objective: To quantify the microorganisms contaminating the common preservatives used in food as well as to detect their in vitro anti-bacterial traits. Methods: A total of 9 preservatives were subjected to conventional cultural and biochemical methods for microbial enumeration. Anti-bacterial activities were demonstrated through the agar well diffusion method. Results: All samples were found to be contaminated with bacteria up to 105 CFU/g and with the fungal flora within a range of 1 01-1 02 CFU/g. Escherichia coli, Pseudomonas spp. and Staphylococcus spp. were demonstrated in most of the samples. Sodium sulfite and citric acid possessed the strongest anti-bacterial trait against all of the test bacteria. Acetic acid exhibited activity against 6 out of 8 test bacteria while vinegar exhibited the activity against 4 bacteria. Activity of salt was demonstrated only against Listeria spp. and Bacillus spp., while activity of sugar and honey was found only against Escherichia coli and Klebsiella spp., respectively. Conclusions: According to the current investigation, sodium sulfite and citric acid samples were found to be satisfactory preservatives both in terms of microbiological criteria and their antibacterial traits.

Generation of acid mine drainage around the Karaerik copper mine (Espiye, Giresun, NE Turkey): implications from the bacterial population in the Acısu effluent.

Science.gov (United States)

Sağlam, Emine Selva; Akçay, Miğraç; Çolak, Dilşat Nigar; İnan Bektaş, Kadriye; Beldüz, Ali Osman

2016-09-01

The Karaerik Cu mine is a worked-out deposit with large volumes of tailings and slags which were left around the mine site without any protection. Natural feeding of these material and run-off water from the mineralised zones into the Acısu effluent causes a serious environmental degradation and creation of acid mine drainage (AMD) along its entire length. This research aims at modelling the formation of AMD with a specific attempt on the characterisation of the bacterial population in association with AMD and their role on its occurrence. Based on 16SrRNA analyses of the clones obtained from a composite water sample, the bacterial community was determined to consist of Acidithiobacillus ferrivorans, Ferrovum myxofaciens, Leptospirillum ferrooxidans and Acidithiobacillus ferrooxidans as iron-oxidising bacteria, Acidocella facilis, Acidocella aluminiidurans, Acidiphilium cryptum and Acidiphilium multivorum as iron-reducing bacteria, and Acidithiobacillus ferrivorans, Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Acidiphilium cryptum as sulphur-oxidising bacteria. This association of bacteria with varying roles was interpreted as evidence of a concomitant occurrence of sulphur and iron cycles during the generation of AMD along the Acısu effluent draining the Karaerik mine.

Determination of transcriptional units and gene products from the ftsA region of Escherichia coli.

Science.gov (United States)

Lutkenhaus, J F; Wu, H C

1980-01-01

Lambda transducing phage gamma 16-2 carries the genes envA, ftsZ, ftsA, ddl, and murC and directs the synthesis of six unique proteins in ultraviolet-irradiated cells. Various derivatives of gamma 16-2 carrying smaller segments of the bacterial deoxyribonucleic acid have also been analyzed for their capacity to direct protein synthesis in ultraviolet-irradiated cells. These results, in combination with genetic results, have allowed the gene product of each of these genes to be assigned. In addition, an unidentified gene was located counterclockwise to murC between murC and murF. Analysis of the direction of transcription indicates that murC, ddl, ftsA, and ftsZ are transcribed clockwise on the Escherichia coli genetic map, and envA is transcribed counterclockwise. In addition, it is shown that each of the genes envA, ftsZ, and ftsA can be expressed independently. Images PMID:6447690

Bioleaching of Arsenic-Rich Gold Concentrates by Bacterial Flora before and after Mutation

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Xuehui Xie

2013-01-01

Full Text Available In order to improve the bioleaching efficiency of arsenic-rich gold concentrates, a mixed bacterial flora had been developed, and the mutation breeding method was adopted to conduct the research. The original mixed bacterial flora had been enrichedin acid mine drainage of Dexing copper mine, Jiangxi Province, China. It was induced by UV (ultraviolet, ultrasonic, and microwave, and their combination mutation. The most efficient bacterial flora after mutation was collected for further bioleaching of arsenic-rich gold concentrates. Results indicated that the bacterial flora after mutation by UV 60 s combined with ultrasonic 10 min had the best oxidation rate of ferrous, the biggest density of cells, and the most activity of total protein. During bioleaching of arsenic-rich gold concentrates, the density of the mutant bacterial cells reached to 1.13×108 cells/mL at 15 days, more than 10 times compared with that of the original culture. The extraction of iron reached to 95.7% after 15 days, increased by 9.9% compared with that of the original culture. The extraction of arsenic reached to 92.6% after 12 days, which was increased by 46.1%. These results suggested that optimum combined mutation could improve leaching ability of the bacterial flora more significantly.

Bioleaching of Arsenic-Rich Gold Concentrates by Bacterial Flora before and after Mutation

Science.gov (United States)

Xie, Xuehui; Yuan, Xuewu; Liu, Na; Chen, Xiaoguang; Abdelgadir, Awad; Liu, Jianshe

2013-01-01

In order to improve the bioleaching efficiency of arsenic-rich gold concentrates, a mixed bacterial flora had been developed, and the mutation breeding method was adopted to conduct the research. The original mixed bacterial flora had been enrichedin acid mine drainage of Dexing copper mine, Jiangxi Province, China. It was induced by UV (ultraviolet), ultrasonic, and microwave, and their combination mutation. The most efficient bacterial flora after mutation was collected for further bioleaching of arsenic-rich gold concentrates. Results indicated that the bacterial flora after mutation by UV 60 s combined with ultrasonic 10 min had the best oxidation rate of ferrous, the biggest density of cells, and the most activity of total protein. During bioleaching of arsenic-rich gold concentrates, the density of the mutant bacterial cells reached to 1.13 × 108 cells/mL at 15 days, more than 10 times compared with that of the original culture. The extraction of iron reached to 95.7% after 15 days, increased by 9.9% compared with that of the original culture. The extraction of arsenic reached to 92.6% after 12 days, which was increased by 46.1%. These results suggested that optimum combined mutation could improve leaching ability of the bacterial flora more significantly. PMID:24381948

Bacterial Abundance and Activity across Sites within Two Northern Wisconsin Sphagnum Bogs.

Science.gov (United States)

Fisher; Graham; Graham

1998-11-01

Abstract Bacterial abundance, temperature, pH, and dissolved organic carbon (DOC) concentration were compared across surface sites within and between two northern Wisconsin Sphagnum peatlands over the summer seasons in 1995 and 1996. Sites of interest were the Sphagnum mat surface, the water-filled moat (lagg) at the bog margin, and the bog lake littoral zone. Significant differences in both bacterial populations and water chemistry were observed between sites. pH was highest in the lake and lowest in the mat at both bogs; the opposite was true for DOC. Large populations of bacteria were present in surface interstitial water from the mat; abundance in this site was consistently higher than in the moat or lake. Bacterial abundance also increased across sites of increasing DOC concentration and declining pH. Bacterial activities (rates of [3H]leucine incorporation) and growth in dilution cultures (with grazers removed) were also assessed in lake, moat, and mat sites. Results using these measures generally supported the trends observed in abundance, although high rates of [3H]leucine incorporation were recorded in the moat at one of the bogs. Our results indicate that bacterial populations in Sphagnum peatlands are not adversely affected by acidity, and that DOC may be more important than pH in determining bacterial abundance in these environments.

Bacterial periplasmic sialic acid-binding proteins exhibit a conserved binding site

Energy Technology Data Exchange (ETDEWEB)

Gangi Setty, Thanuja [Institute for Stem Cell Biology and Regenerative Medicine, NCBS Campus, GKVK Post, Bangalore, Karnataka 560 065 (India); Cho, Christine [Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109 (United States); Govindappa, Sowmya [Institute for Stem Cell Biology and Regenerative Medicine, NCBS Campus, GKVK Post, Bangalore, Karnataka 560 065 (India); Apicella, Michael A. [Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109 (United States); Ramaswamy, S., E-mail: ramas@instem.res.in [Institute for Stem Cell Biology and Regenerative Medicine, NCBS Campus, GKVK Post, Bangalore, Karnataka 560 065 (India)

2014-07-01

Structure–function studies of sialic acid-binding proteins from F. nucleatum, P. multocida, V. cholerae and H. influenzae reveal a conserved network of hydrogen bonds involved in conformational change on ligand binding. Sialic acids are a family of related nine-carbon sugar acids that play important roles in both eukaryotes and prokaryotes. These sialic acids are incorporated/decorated onto lipooligosaccharides as terminal sugars in multiple bacteria to evade the host immune system. Many pathogenic bacteria scavenge sialic acids from their host and use them for molecular mimicry. The first step of this process is the transport of sialic acid to the cytoplasm, which often takes place using a tripartite ATP-independent transport system consisting of a periplasmic binding protein and a membrane transporter. In this paper, the structural characterization of periplasmic binding proteins from the pathogenic bacteria Fusobacterium nucleatum, Pasteurella multocida and Vibrio cholerae and their thermodynamic characterization are reported. The binding affinities of several mutations in the Neu5Ac binding site of the Haemophilus influenzae protein are also reported. The structure and the thermodynamics of the binding of sugars suggest that all of these proteins have a very well conserved binding pocket and similar binding affinities. A significant conformational change occurs when these proteins bind the sugar. While the C1 carboxylate has been identified as the primary binding site, a second conserved hydrogen-bonding network is involved in the initiation and stabilization of the conformational states.

Bacterial periplasmic sialic acid-binding proteins exhibit a conserved binding site

International Nuclear Information System (INIS)

Gangi Setty, Thanuja; Cho, Christine; Govindappa, Sowmya; Apicella, Michael A.; Ramaswamy, S.

2014-01-01

Structure–function studies of sialic acid-binding proteins from F. nucleatum, P. multocida, V. cholerae and H. influenzae reveal a conserved network of hydrogen bonds involved in conformational change on ligand binding. Sialic acids are a family of related nine-carbon sugar acids that play important roles in both eukaryotes and prokaryotes. These sialic acids are incorporated/decorated onto lipooligosaccharides as terminal sugars in multiple bacteria to evade the host immune system. Many pathogenic bacteria scavenge sialic acids from their host and use them for molecular mimicry. The first step of this process is the transport of sialic acid to the cytoplasm, which often takes place using a tripartite ATP-independent transport system consisting of a periplasmic binding protein and a membrane transporter. In this paper, the structural characterization of periplasmic binding proteins from the pathogenic bacteria Fusobacterium nucleatum, Pasteurella multocida and Vibrio cholerae and their thermodynamic characterization are reported. The binding affinities of several mutations in the Neu5Ac binding site of the Haemophilus influenzae protein are also reported. The structure and the thermodynamics of the binding of sugars suggest that all of these proteins have a very well conserved binding pocket and similar binding affinities. A significant conformational change occurs when these proteins bind the sugar. While the C1 carboxylate has been identified as the primary binding site, a second conserved hydrogen-bonding network is involved in the initiation and stabilization of the conformational states

Viruses of the Archaea

DEFF Research Database (Denmark)

Basta, T.; Garrett, Roger Antony; Prangishvili,, David

2009-01-01

Double-stranded deoxyribonucleic acid (DNA) viruses that infect members of the third domain of life, the Archaea, are diverse and exceptional in both their morphotypes and their genomic properties. The majority of characterized species infect hyperthermophilic hosts and carry morphological featur...

Filling gaps in bacterial amino acid biosynthesis pathways with high-throughput genetics.

Directory of Open Access Journals (Sweden)

Morgan N Price

2018-01-01

Full Text Available For many bacteria with sequenced genomes, we do not understand how they synthesize some amino acids. This makes it challenging to reconstruct their metabolism, and has led to speculation that bacteria might be cross-feeding amino acids. We studied heterotrophic bacteria from 10 different genera that grow without added amino acids even though an automated tool predicts that the bacteria have gaps in their amino acid synthesis pathways. Across these bacteria, there were 11 gaps in their amino acid biosynthesis pathways that we could not fill using current knowledge. Using genome-wide mutant fitness data, we identified novel enzymes that fill 9 of the 11 gaps and hence explain the biosynthesis of methionine, threonine, serine, or histidine by bacteria from six genera. We also found that the sulfate-reducing bacterium Desulfovibrio vulgaris synthesizes homocysteine (which is a precursor to methionine by using DUF39, NIL/ferredoxin, and COG2122 proteins, and that homoserine is not an intermediate in this pathway. Our results suggest that most free-living bacteria can likely make all 20 amino acids and illustrate how high-throughput genetics can uncover previously-unknown amino acid biosynthesis genes.

Soil water availability and microsite mediate fungal and bacterial phospholipid fatty acid biomarker abundances in Mojave Desert soils exposed to elevated atmospheric CO2

Science.gov (United States)

Jin, V. L.; Schaeffer, S. M.; Ziegler, S. E.; Evans, R. D.

2011-06-01

Changes in the rates of nitrogen (N) cycling, microbial carbon (C) substrate use, and extracellular enzyme activities in a Mojave Desert ecosystem exposed to elevated atmospheric CO2 suggest shifts in the size and/or functional characteristics of microbial assemblages in two dominant soil microsites: plant interspaces and under the dominant shrub Larrea tridentata. We used ester-linked phospholipid fatty acid (PLFA) biomarkers as a proxy for microbial biomass to quantify spatial and temporal differences in soil microbial communities from February 2003 to May 2005. Further, we used the 13C signature of the fossil CO2 source for elevated CO2 plots to trace recent plant C inputs into soil organic matter (SOM) and broad microbial groups using δ13C (‰). Differences between individual δ13CPLFA and δ13CSOM for fungal biomarkers indicated active metabolism of newer C in elevated CO2 soils. Total PLFA-C was greater in shrub microsites compared to plant interspaces, and CO2 treatment differences within microsites increased under higher soil water availability. Total, fungal, and bacterial PLFA-C increased with decreasing soil volumetric water content (VWC) in both microsites, suggesting general adaptations to xeric desert conditions. Increases in fungal-to-bacterial PLFA-C ratio with decreasing VWC reflected functional group-specific responses to changing soil water availability. While temporal and spatial extremes in resource availability in desert ecosystems contribute to the difficulty in identifying common trends or mechanisms driving microbial responses in less extreme environments, we found that soil water availability and soil microsite interacted with elevated CO2 to shift fungal and bacterial biomarker abundances in Mojave Desert soils.

Surface layers of Xanthomonas malvacearum, the cause of bacterial blight of cotton.

Science.gov (United States)

Verma, J P; Formanek, H

1981-01-01

Mureins were isolated from two strains of Xanthomonas malvacearum, a phytopathogenic bacterium causing bacterial blight of cotton. The purity of murein was 70-95 % and the amino acid and amino sugar components (glutamic acid, alanina, meso-disminopimelic acid, muramic acid and glucosamine) were present at the molar ratio of 1:1.9:1:l.12.0.85. The bacterium secreted a copious amount of slime which masked itd surface structure. The slime was composed of densley interwoven network of filamentous material originating from the cell surface and extended into the medium without and discernable boundary. The slime was secreted through surface layers pores by force, giving the effect of a spray or jet. Slime also played a role in chain formatin of baterial cells.

Electrostatic behavior of the charge-regulated bacterial cell surface.

Science.gov (United States)

Hong, Yongsuk; Brown, Derick G

2008-05-06

The electrostatic behavior of the charge-regulated surfaces of Gram-negative Escherichia coli and Gram-positive Bacillus brevis was studied using numerical modeling in conjunction with potentiometric titration and electrophoretic mobility data as a function of solution pH and electrolyte composition. Assuming a polyelectrolytic polymeric bacterial cell surface, these experimental and numerical analyses were used to determine the effective site numbers of cell surface acid-base functional groups and Ca(2+) sorption coefficients. Using effective site concentrations determined from 1:1 electrolyte (NaCl) experimental data, the charge-regulation model was able to replicate the effects of 2:1 electrolyte (CaCl(2)), both alone and as a mixture with NaCl, on the measured zeta potential using a single Ca(2+) surface binding constant for each of the bacterial species. This knowledge is vital for understanding how cells respond to changes in solution pH and electrolyte composition as well as how they interact with other surfaces. The latter is especially important due to the widespread use of the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory in the interpretation of bacterial adhesion. As surface charge and surface potential both vary on a charge-regulated surface, accurate modeling of bacterial interactions with surfaces ultimately requires use of an electrostatic model that accounts for the charge-regulated nature of the cell surface.

Bacterially Induced Weathering of Ultramafic Rock and Its Implications for Phytoextraction

Science.gov (United States)

Kidd, Petra; Kuffner, Melanie; Prieto-Fernández, Ángeles; Hann, Stephan; Monterroso, Carmela; Sessitsch, Angela; Wenzel, Walter; Puschenreiter, Markus

2013-01-01

The bioavailability of metals in soil is often cited as a limiting factor of phytoextraction (or phytomining). Bacterial metabolites, such as organic acids, siderophores, or biosurfactants, have been shown to mobilize metals, and their use to improve metal extraction has been proposed. In this study, the weathering capacities of, and Ni mobilization by, bacterial strains were evaluated. Minimal medium containing ground ultramafic rock was inoculated with either of two Arthrobacter strains: LA44 (indole acetic acid [IAA] producer) or SBA82 (siderophore producer, PO4 solubilizer, and IAA producer). Trace elements and organic compounds were determined in aliquots taken at different time intervals after inoculation. Trace metal fractionation was carried out on the remaining rock at the end of the experiment. The results suggest that the strains act upon different mineral phases. LA44 is a more efficient Ni mobilizer, apparently solubilizing Ni associated with Mn oxides, and this appeared to be related to oxalate production. SBA82 also leads to release of Ni and Mn, albeit to a much lower extent. In this case, the concurrent mobilization of Fe and Si indicates preferential weathering of Fe oxides and serpentine minerals, possibly related to the siderophore production capacity of the strain. The same bacterial strains were tested in a soil-plant system: the Ni hyperaccumulator Alyssum serpyllifolium subsp. malacitanum was grown in ultramafic soil in a rhizobox system and inoculated with each bacterial strain. At harvest, biomass production and shoot Ni concentrations were higher in plants from inoculated pots than from noninoculated pots. Ni yield was significantly enhanced in plants inoculated with LA44. These results suggest that Ni-mobilizing inoculants could be useful for improving Ni uptake by hyperaccumulator plants. PMID:23793627

Supercritical Fluid Extraction of Bacterial and Archaeal Lipid Biomarkers from Anaerobically Digested Sludge

Directory of Open Access Journals (Sweden)

Koichi Fujie

2012-03-01

Full Text Available Supercritical fluid extraction (SFE was used in the analysis of bacterial respiratory quinone (RQ, bacterial phospholipid fatty acid (PLFA, and archaeal phospholipid ether lipid (PLEL from anaerobically digested sludge. Bacterial RQ were determined using ultra performance liquid chromatography (UPLC. Determination of bacterial PLFA and archaeal PLEL was simultaneously performed using gas chromatography-mass spectrometry (GC-MS. The effects of pressure, temperature, and modifier concentration on the total amounts of RQ, PLFA, and PLEL were investigated by 23 experiments with five settings chosen for each variable. The optimal extraction conditions that were obtained through a multiple-response optimization included a pressure of 23.6 MPa, temperature of 77.6 °C, and 10.6% (v/v of methanol as the modifier. Thirty nine components of microbial lipid biomarkers were identified in the anaerobically digested sludge. Overall, the SFE method proved to be more effective, rapid, and quantitative for simultaneously extracting bacterial and archaeal lipid biomarkers, compared to conventional organic solvent extraction. This work shows the potential application of SFE as a routine method for the comprehensive analysis of microbial community structures in environmental assessments using the lipid biomarkers profile.

The effect of gamma irradiation on the nucleic acids content of the mediterranean fruit fly ceratitis capitata (Wied)

International Nuclear Information System (INIS)

Fadel, A.M.; Amin, T.R.; Al-Elimi, M.H.

1999-01-01

This work was carried out study the effect of gamma irradiation on the deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) content in the whole body homogenate of the mediterranean fruit fly, ceratitis capitata (Wied.) pupae were gamma irradiated with different doses (o, 50, 70, 90 and 110 Gy) at two different pupal ages (2 and 4 days before adult emergence ) to estimate the nucleic acids in pupae and adult males, and females. Experimental results showed that gamma irradiation of pupae reduced RNA content, and this reduction was proportional with the applied dose and more pronounced in the younger pupae. However, DNA content was reduced only when the highest dose was applied to pupae irradiated 2 days before adult emergence (older pupae). Concerning adult insects which were gamma irradiated as pupae, the results revealed, generally, that males and females which were irradiated 2 days before adult emergence were more affected than those irradiated 4 days before adult emergence. The male DNA content and the female RNA content showed high degrees of reduction which, more or less, increased with increasing the dose used. On the other hand, female DNA and male RNA contents were slightly, changed. The significant importance of the results and some statistical interrelations were discussed

Hop acid-rich spent craft brewer's yeast modulates gut bacterial growth

Science.gov (United States)

Alpha and beta hop acids (humulones and lupulones) from Humulus lupulus are inhibitors of Gram-positive organisms and important natural antibiotics for beer fermentation and carbohydrate feed stocks for biofuel production. Recent observations (Bryant and Cohen) of high levels of hop acids in spent ...

Bacterial Shifts in Nutrient Solutions Flowing Through Biofilters Used in Tomato Soilless Culture.

Science.gov (United States)

Renault, David; Déniel, Franck; Vallance, Jessica; Bruez, Emilie; Godon, Jean-Jacques; Rey, Patrice

2017-11-25

In soilless culture, slow filtration is used to eliminate plant pathogenic microorganisms from nutrient solutions. The present study focused on the characterization and the potential functions of microbial communities colonizing the nutrient solutions recycled on slow filters during a whole cultivation season of 7 months in a tomato growing system. Bacterial microflora colonizing the solutions before and after they flew through the columns were studied. Two filters were amended with Pseudomonas putida (P-filter) or Bacillus cereus strains (B-filter), and a third filter was a control (C-filter). Biological activation of filter unit through bacterial amendment enhanced very significantly filter efficacy against plant potential pathogens Pythium spp. and Fusarium oxysporum. However, numerous bacteria (10 3 -10 4  CFU/mL) were detected in the effluent solutions. The community-level physiological profiling indicated a temporal shift of bacterial microflora, and the metabolism of nutrient solutions originally oriented towards carbohydrates progressively shifted towards degradation of amino acids and carboxylic acids over the 7-month period of experiment. Single-strand conformation polymorphism fingerprinting profiles showed that a shift between bacterial communities colonizing influent and effluent solutions of slow filters occurred. In comparison with influent, 16S rDNA sequencing revealed that phylotype diversity was low in the effluent of P- and C-filters, but no reduction was observed in the effluent of the B-filter. Suppressive potential of solutions filtered on a natural filter (C-filter), where the proportion of Proteobacteria (α- and β-) increased, whereas the proportion of uncultured candidate phyla rose in P- and B-filters, is discussed.

Bacterial communities in batch and continuous-flow wetlands treating the herbicide S-metolachlor

Energy Technology Data Exchange (ETDEWEB)

Elsayed, O.F. [Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS (France); Génétique Moléculaire, Génomique, Microbiologie (GMGM), UMR 7156 University of Strasbourg/CNRS (France); Maillard, E. [Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS (France); Vuilleumier, S. [Génétique Moléculaire, Génomique, Microbiologie (GMGM), UMR 7156 University of Strasbourg/CNRS (France); Imfeld, G., E-mail: imfeld@unistra.fr [Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS (France)

2014-11-15

Knowledge of wetland bacterial communities in the context of pesticide contamination and hydrological regime is scarce. We investigated the bacterial composition in constructed wetlands receiving Mercantor Gold{sup ®} contaminated water (960 g L{sup −1} of the herbicide S-metolachlor, > 80% of the S-enantiomer) operated under continuous-flow or batch modes to evaluate the impact of the hydraulic regime. In the continuous-flow wetland, S-metolachlor mass removal was > 40%, whereas in the batch wetland, almost complete removal of S-metolachlor (93–97%) was observed. Detection of ethanesulfonic and oxanilic acid degradation products further indicated S-metolachlor biodegradation in the two wetlands. The dominant bacterial populations were characterised by terminal restriction fragment length polymorphism (T-RFLP) and 454 pyrosequencing. The bacterial profiles evolved during the first 35 days of the experiment, starting from a composition similar to that of inlet water, with the use of nitrate and to a lesser extent sulphate and manganese as terminal electron acceptors for microbial metabolism. Proteobacteria were the most abundant phylum, with Beta-, Alpha- and Gammaproteobacteria representing 26%, 19% and 17% respectively of total bacterial abundance. Bacterial composition in wetland water changed gradually over time in continuous-flow wetland and more abruptly in the batch wetland. Differences in overall bacterial water structure in the two systems were modest but significant (p = 0.008), and S-metolachlor, nitrate, and total inorganic carbon concentrations correlated with changes in the bacterial profiles. Together, the results highlight that bacterial composition profiles and their dynamics may be used as bioindicators of herbicide exposure and hydraulic disturbances in wetland systems. - Highlights: • We evaluated the bacterial composition in wetlands treating S-metolachlor • Hydraulic regime impacted biogeochemical processes and S-metolachlor removal �

Bacterial communities in batch and continuous-flow wetlands treating the herbicide S-metolachlor

International Nuclear Information System (INIS)

Elsayed, O.F.; Maillard, E.; Vuilleumier, S.; Imfeld, G.

2014-01-01

Knowledge of wetland bacterial communities in the context of pesticide contamination and hydrological regime is scarce. We investigated the bacterial composition in constructed wetlands receiving Mercantor Gold ® contaminated water (960 g L −1 of the herbicide S-metolachlor, > 80% of the S-enantiomer) operated under continuous-flow or batch modes to evaluate the impact of the hydraulic regime. In the continuous-flow wetland, S-metolachlor mass removal was > 40%, whereas in the batch wetland, almost complete removal of S-metolachlor (93–97%) was observed. Detection of ethanesulfonic and oxanilic acid degradation products further indicated S-metolachlor biodegradation in the two wetlands. The dominant bacterial populations were characterised by terminal restriction fragment length polymorphism (T-RFLP) and 454 pyrosequencing. The bacterial profiles evolved during the first 35 days of the experiment, starting from a composition similar to that of inlet water, with the use of nitrate and to a lesser extent sulphate and manganese as terminal electron acceptors for microbial metabolism. Proteobacteria were the most abundant phylum, with Beta-, Alpha- and Gammaproteobacteria representing 26%, 19% and 17% respectively of total bacterial abundance. Bacterial composition in wetland water changed gradually over time in continuous-flow wetland and more abruptly in the batch wetland. Differences in overall bacterial water structure in the two systems were modest but significant (p = 0.008), and S-metolachlor, nitrate, and total inorganic carbon concentrations correlated with changes in the bacterial profiles. Together, the results highlight that bacterial composition profiles and their dynamics may be used as bioindicators of herbicide exposure and hydraulic disturbances in wetland systems. - Highlights: • We evaluated the bacterial composition in wetlands treating S-metolachlor • Hydraulic regime impacted biogeochemical processes and S-metolachlor removal �

Crystal structures of B-DNA dodecamer containing the epigenetic modifications 5-hydroxymethylcytosine or 5-methylcytosine

Czech Academy of Sciences Publication Activity Database

Renčiuk, Daniel; Blacque, O.; Vorlíčková, Michaela; Spingler, B.

2013-01-01

Roč. 41, č. 21 (2013), s. 9891-9900 ISSN 0305-1048 R&D Projects: GA ČR GAP205/12/0466; GA MŠk(CZ) ED1.1.00/02.0068 Institutional research plan: CEZ:AV0Z50040702 Institutional support: RVO:68081707 Keywords : NUCLEIC-ACID STRUCTURES * CIRCULAR-DICHROISM * DEOXYRIBONUCLEIC-ACID Subject RIV: BO - Biophysics Impact factor: 8.808, year: 2013

Bacterial and fungal markers in tobacco smoke

International Nuclear Information System (INIS)

Szponar, B.; Pehrson, C.; Larsson, L.

2012-01-01

Previous research has demonstrated that cigarette smoke contains bacterial and fungal components including lipopolysaccharide (LPS) and ergosterol. In the present study we used gas chromatography–mass spectrometry to analyze tobacco as well as mainstream and second hand smoke for 3-hydroxy fatty acids (3-OH FAs) of 10 to 18 carbon chain lengths, used as LPS markers, and ergosterol, used as a marker of fungal biomass. The air concentrations of LPS were 0.0017 nmol/m 3 (N = 5) and 0.0007/m 3 (N = 6) in the smoking vs. non-smoking rooms (p = 0.0559) of the studied private houses, and 0.0231 nmol/m 3 (N = 5) vs. 0.0006 nmol/m 3 (N = 5) (p = 0.0173), respectively, at the worksite. The air concentrations of ergosterol were also significantly higher in rooms with ongoing smoking than in rooms without smoking. A positive correlation was found between LPS and ergosterol in rooms with smoking but not in rooms without smoking. 3-OH C14:0 was the main 3-OH FA, followed by 3-OH C12:0, both in mainstream and second hand smoke and in phenol:water smoke extracts prepared in order to purify the LPS. The Limulus activity of the phenolic phase of tobacco was 3900 endotoxin units (EU)/cigarette; the corresponding amount of the smoke, collected on filters from 8 puffs, was 4 EU/cigarette. Tobacco smoking has been associated with a range of inflammatory airway conditions including COPD, asthma, bronchitis, alveolar hypersensitivity etc. Significant levels of LPS and ergosterol were identified in tobacco smoke and these observations support the hypothesis that microbial components of tobacco smoke contribute to inflammation and airway disease. -- Highlights: ► Air concentration of bacterial and fungal markers is significantly higher in rooms with ongoing smoking than without smoking. ► Bacterial LPS correlates with fungal marker in rooms with ongoing smoking but not without smoking. ► LPS from mainstream smoke contains 3-hydroxy 14:0 and 12:0 fatty acids in similar proportion as

Antibacterial Effect of Gallic Acid against Aeromonas hydrophila and Aeromonas sobria Through Damaging Membrane Integrity.

Science.gov (United States)

Lu, Jing; Wang, Zhenning; Ren, Mengrou; Huang, Guoren; Fang, Baochen; Bu, Xiujuan; Liu, Yanhui; Guan, Shuang

In the study, we investigated the antibacterial activity and mechanism of gallic acid against Aeromonas hydrophila and Aeromonas sobria. Gallic acid showed strong antimicrobial activity against the two bacteria. Furthermore, the antibacterial mechanism of gallic acid (0, 3, 6, 12 mM) was performed by membrane integrity assay and scanning electron microscopy (SEM) assay. The results showed that gallic acid notably increased the released material absorption value at 260, 280 nm and electric conductivity in a dose-dependent manner. Moreover, the SEM assay showed that gallic acid induced severe shrink of bacterial intima and irregular morphology in a dose-dependent manner. The SDS-PAGE profiles further confirmed that gallic acid could damage bacterial cells. These results indicated gallic acid exhibited antibacterial effect by destroying membrane integrity of A. hydrophila and A. sobria. Hence, gallic acid has great potential as a new natural food preservative in food fresh-keeping and storage.

Genome-wide Studies of Mycolic Acid Bacteria: Computational Identification and Analysis of a Minimal Genome

KAUST Repository

Kamanu, Frederick Kinyua

2012-12-01

The mycolic acid bacteria are a distinct suprageneric group of asporogenous Grampositive, high GC-content bacteria, distinguished by the presence of mycolic acids in their cell envelope. They exhibit great diversity in their cell and morphology; although primarily non-pathogens, this group contains three major pathogens Mycobacterium leprae, Mycobacterium tuberculosis complex, and Corynebacterium diphtheria. Although the mycolic acid bacteria are a clearly defined group of bacteria, the taxonomic relationships between its constituent genera and species are less well defined. Two approaches were tested for their suitability in describing the taxonomy of the group. First, a Multilocus Sequence Typing (MLST) experiment was assessed and found to be superior to monophyletic (16S small ribosomal subunit) in delineating a total of 52 mycolic acid bacterial species. Phylogenetic inference was performed using the neighbor-joining method. To further refine phylogenetic analysis and to take advantage of the widespread availability of bacterial genome data, a computational framework that simulates DNA-DNA hybridisation was developed and validated using multiscale bootstrap resampling. The tool classifies microbial genomes based on whole genome DNA, and was deployed as a web-application using PHP and Javascript. It is accessible online at http://cbrc.kaust.edu.sa/dna_hybridization/ A third study was a computational and statistical methods in the identification and analysis of a putative minimal mycolic acid bacterial genome so as to better understand (1) the genomic requirements to encode a mycolic acid bacterial cell and (2) the role and type of genes and genetic elements that lead to the massive increase in genome size in environmental mycolic acid bacteria. Using a reciprocal comparison approach, a total of 690 orthologous gene clusters forming a putative minimal genome were identified across 24 mycolic acid bacterial species. In order to identify new potential drug

Structure of a bacterial toxin-activating acyltransferase.

Science.gov (United States)

Greene, Nicholas P; Crow, Allister; Hughes, Colin; Koronakis, Vassilis

2015-06-09

Secreted pore-forming toxins of pathogenic Gram-negative bacteria such as Escherichia coli hemolysin (HlyA) insert into host-cell membranes to subvert signal transduction and induce apoptosis and cell lysis. Unusually, these toxins are synthesized in an inactive form that requires posttranslational activation in the bacterial cytosol. We have previously shown that the activation mechanism is an acylation event directed by a specialized acyl-transferase that uses acyl carrier protein (ACP) to covalently link fatty acids, via an amide bond, to specific internal lysine residues of the protoxin. We now reveal the 2.15-Å resolution X-ray structure of the 172-aa ApxC, a toxin-activating acyl-transferase (TAAT) from pathogenic Actinobacillus pleuropneumoniae. This determination shows that bacterial TAATs are a structurally homologous family that, despite indiscernible sequence similarity, form a distinct branch of the Gcn5-like N-acetyl transferase (GNAT) superfamily of enzymes that typically use acyl-CoA to modify diverse bacterial, archaeal, and eukaryotic substrates. A combination of structural analysis, small angle X-ray scattering, mutagenesis, and cross-linking defined the solution state of TAATs, with intermonomer interactions mediated by an N-terminal α-helix. Superposition of ApxC with substrate-bound GNATs, and assay of toxin activation and binding of acyl-ACP and protoxin peptide substrates by mutated ApxC variants, indicates the enzyme active site to be a deep surface groove.

An investigation of total bacterial communities, culturable antibiotic-resistant bacterial communities and integrons in the river water environments of Taipei city.

Science.gov (United States)

Yang, Chu-Wen; Chang, Yi-Tang; Chao, Wei-Liang; Shiung, Iau-Iun; Lin, Han-Sheng; Chen, Hsuan; Ho, Szu-Han; Lu, Min-Jheng; Lee, Pin-Hsuan; Fan, Shao-Ning

2014-07-30

The intensive use of antibiotics may accelerate the development of antibiotic-resistant bacteria (ARB). The global geographical distribution of environmental ARB has been indicated by many studies. However, the ARB in the water environments of Taiwan has not been extensively investigated. The objective of this study was to investigate the communities of ARB in Huanghsi Stream, which presents a natural acidic (pH 4) water environment. Waishuanghsi Stream provides a neutral (pH 7) water environment and was thus also monitored to allow comparison. The plate counts of culturable bacteria in eight antibiotics indicate that the numbers of culturable carbenicillin- and vancomycin-resistant bacteria in both Huanghsi and Waishuanghsi Streams are greater than the numbers of culturable bacteria resistant to the other antibiotics tested. Using a 16S rDNA sequencing approach, both the antibiotic-resistant bacterial communities (culture-based) and the total bacterial communities (metagenome-based) in Waishuanghsi Stream exhibit a higher diversity than those in Huanghsi Stream were observed. Of the three classes of integron, only class I integrons were identified in Waishuanghsi Stream. Our results suggest that an acidic (pH 4) water environment may not only affect the community composition of antibiotic-resistant bacteria but also the horizontal gene transfer mediated by integrons. Copyright © 2013 Elsevier B.V. All rights reserved.

Wickerhamiella van der Walt (1973)

Science.gov (United States)

This chapter describes the ascomycetous yeast genus Wickerhamiella, which has five described species and has been defined from multigene deoxyribonucleic acid (DNA) sequence analysis. The species reproduce by multilateral budding but do not form hyphae or pseudohyphae. Asci typically form a single a...

How SNP chips will advance our knowledge of factors controlling puberty and aid in selecting replacement females

Science.gov (United States)

The promise of genomic selection is that genetic potential can be accurately predicted from genotypes. Simple deoxyribonucleic acid (DNA) tests might replace low accuracy predictions based on performance and pedigree for expensive or lowly heritable measures of puberty and fertility. The promise i...

Effects of acid deposition on microbial processes in natural waters

International Nuclear Information System (INIS)

Gilmour, C.C.

1992-01-01

Biogeochemical processes mediated by microorganisms are not adversely affected by the acidification of natural waters to the same extent as are the life cycles of higher organisms. Basic processes, e.g., primary production and organic matter decomposition, are not slowed in moderately acidified systems and do not generally decline above a pH of 5. More specifically, the individual components of the carbon, nitrogen, and sulfur cycles are, with few exceptions, also acid resistant. The influence of acid deposition on microbial processes is more often stimulation of nitrogen and sulfur cycling, often leading to alkalinity production, which mitigates the effect of strong acid deposition. Bacterial sulfate reduction and denitrification in sediments are two of the major processes that can be stimulated by sulfate and nitrate deposition, respectively, and result in ANC (acid-neutralizing capacity) generation. One of the negative effects of acid deposition is increased mobilization and bioaccumulation of some metals. Bacteria appear to play an important role, especially in mercury cycling, with acidification leading to increased bacterial methylation of mercury and subsequent bioaccumulation in higher organisms

Bacterial community from gut of white shrimp, Penaeus vannamei, cultured in earthen ponds

Directory of Open Access Journals (Sweden)

Supamattaya, K.

2007-05-01

Full Text Available The Fluorescent in situ hybridization (FISH technique and conventional method were used to analyse the bacterial community in the gut of white shrimp cultured in earthen ponds. Samples were collectedfrom three parts, hepatopancreas, anterior intestine and posterior intestine. Gut bacterial community was enumerated by 15 probes in FISH and 3 bacterial culture technique media. The results showed that bacteriaspecific probes determined bacterial community and Eubacteria as the dominant group of microbial community in the studied gut portions. β-Proteobacteria group (29.53±5.39% and γ-Proteobacteria group (26.18±6.88% were major groups of bacterial flora in the hepatopancreas. In contrast, low G+C gram positive bacteria group (LGC was the most abundant group detected in anterior intestine (36.40±3.53% andposterior intestine (30.32±4.63%. Vibrio spp. were detected very less in hepatopancreas (0.25±0.43% and were present in 3 of 9 samples. In the case of bacterial detection using cultivation method, the number ofbacterial groups verified by TSA, TCBS and MRS showed high variation in every part of the studied digestive tract portions; however, no vibrio or lactic acid bacteria were present in the hepatopancreas ofhealthy shrimp. This study reveals the proportion of bacterial community in the digestive tract of white shrimp which can be used as important database for studying the change of the bacterial community in an abnormal condition including the efficiency of probiotics in the gut (in vivo of white shrimp.

Production and transformation of dissolved neutral sugars and amino acids by bacteria in seawater

DEFF Research Database (Denmark)

Jørgensen, Linda; Lechtenfeld, O.J.; Benner, R.

2014-01-01

production and degradation processes. This study provides insight into the bioavailability of biomolecules as well as the chemical composition of DOM produced by bacteria. The molecular compositions of combined neutral sugars and amino acids were investigated in DOM produced by bacteria and in DOM remaining...... degradation are not strongly influenced by the initial substrate or bacterial community. The molecular composition of neutral sugars released by bacteria was characterized by a high glucose content (47 mol %) and heterogeneous contributions from other neutral sugars (3–14 mol %). DOM remaining after bacterial...... degradation was characterized by a high galactose content (33 mol %), followed by glucose (22 mol %) and the remaining neutral sugars (7–11 mol %). The ratio of D-amino acids to L-amino acids increased during the experiments as a response to bacterial degradation, and after 32 days, the D/L ratios of aspartic...

Bacterial contaminants from frozen puff pastry production process and their growth inhibition by antimicrobial substances from lactic acid bacteria.

Science.gov (United States)

Rumjuankiat, Kittaporn; Keawsompong, Suttipun; Nitisinprasert, Sunee

2017-05-01

Seventy-five bacterial contaminants which still persisted to cleaning system from three puff pastry production lines (dough forming, layer and filling forming, and shock freezing) were identified using 16S rDNA as seven genera of Bacillus , Corynebacterium , Dermacoccus , Enterobacter , Klebsiella, Pseudomonas , and Staphylococcus with detection frequencies of 24.00, 2.66, 1.33, 37.33, 1.33, 2.66, and 30.66, respectively. Seventeen species were discovered while only 11 species Bacillus cereus, B. subtilis, B. pumilus, Corynebacterium striatum , Dermacoccus barathri , Enterobacter asburiae, Staphylococcus kloosii, S. haemolyticus, S. hominis, S. warneri , and S. aureus were detected at the end of production. Based on their abundance, the highest abundance of E. asburiae could be used as a biomarker for product quality. While a low abundance of the mesophile pathogen C. striatum , which causes respiratory and nervous infection and appeared only at the shock freezing step was firstly reported for its detection in bakery product. Six antimicrobial substances (AMSs) from lactic acid bacteria, FF1-4, FF1-7, PFUR-242, PFUR-255, PP-174, and nisin A were tested for their inhibition activities against the contaminants. The three most effective were FF1-7, PP-174, and nisin A exhibiting wide inhibition spectra of 88.00%, 85.33%, and 86.66%, respectively. The potential of a disinfectant solution containing 800 AU/ml of PP-174 and nisin A against the most resistant strains of Enterobacter , Staphylococcus , Bacillus and Klebsiella was determined on artificially contaminated conveyor belt coupons at 0, 4, 8, 12, and 16 hr. The survival levels of the test strains were below 1 log CFU/coupon at 0 hr. The results suggested that a combined solution of PP-174 and nisin A may be beneficial as a sanitizer to inhibit bacterial contaminants in the frozen puff pastry industry.

Les altérations des vins par les bacteries acétiques et les bactéries lactiques

Directory of Open Access Journals (Sweden)

Suzanne Lafon-Lafourcade

1984-03-01

Full Text Available Acetic acid and lactic acid bacteria were present at all stages of wine making. A lower pH and a highter ethanol concentration limit the risks of alteration. During the conservation, a low temperature, good use of S02 and frequent checkings ensure control of bacterial growth and metabolism.

Bacterial mycophagy: definition and diagnosis of a unique bacterial-fungal interaction

NARCIS (Netherlands)

Leveau, J.H.J.; Preston, G.M.

2008-01-01

This review analyses the phenomenon of bacterial mycophagy, which we define as a set of phenotypic behaviours that enable bacteria to obtain nutrients from living fungi and thus allow the conversion of fungal into bacterial biomass. We recognize three types of bacterial strategies to derive

Bacterial Reduction Of Barium Sulphate By Sulphate-Reducing Bacteria

Directory of Open Access Journals (Sweden)

Luptáková Alena

2015-12-01

Full Text Available Acid mine drainage (AMD is a worldwide problem leading to contamination of water sources. AMD are characterized by low pH and high content of heavy metals and sulphates. The barium salts application presents one of the methods for the sulphates removing from AMD. Barium chloride, barium hydroxide and barium sulphide are used for the sulphates precipitation in the form of barium sulphate. Because of high investment costs of barium salts, barium sulphide is recycled from barium sulphate precipitates. It can be recycled by thermic or bacterial reduction of barium sulphate. The aim of our study was to verify experimentally the possibility of the bacterial transformation of BaSO4 to BaS by sulphate-reducing bacteria. Applied BaSO4 came from experiments of sulphates removal from Smolnik AMD using BaCl2.

Structure of a microbial community in soil after prolonged addition of low levels of simulated acid rain

Science.gov (United States)

Pennanen; Fritze; Vanhala; Kiikkila; Neuvonen; Baath

1998-06-01

Humus samples were collected 12 growing seasons after the start of a simulated acid rain experiment situated in the subarctic environment. The acid rain was simulated with H2SO4, a combination of H2SO4 and HNO3, and HNO3 at two levels of moderate acidic loads close to the natural anthropogenic pollution levels of southern Scandinavia. The higher levels of acid applications resulted in acidification, as defined by humus chemistry. The concentrations of base cations decreased, while the concentrations of exchangeable H+, Al, and Fe increased. Humus pH decreased from 3.83 to 3.65. Basal respiration decreased with decreasing humus pH, and total microbial biomass, measured by substrate-induced respiration and total amount of phospholipid fatty acids (PLFA), decreased slightly. An altered PLFA pattern indicated a change in the microbial community structure at the higher levels of acid applications. In general, branched fatty acids, typical of gram-positive bacteria, increased in the acid plots. PLFA analysis performed on the bacterial community growing on agar plates also showed that the relative amount of PLFA specific for gram-positive bacteria increased due to the acidification. The changed bacterial community was adapted to the more acidic environment in the acid-treated plots, even though bacterial growth rates, estimated by thymidine and leucine incorporation, decreased with pH. Fungal activity (measured as acetate incorporation into ergosterol) was not affected. This result indicates that bacteria were more affected than fungi by the acidification. The capacity of the bacterial community to utilize 95 different carbon sources was variable and only showed weak correlations to pH. Differences in the toxicities of H2SO4 and HNO3 for the microbial community were not found.

Field investigations of bacterial contaminants and their effects on extended porcine semen.

Science.gov (United States)

Althouse, G C; Kuster, C E; Clark, S G; Weisiger, R M

2000-03-15

Field investigations (n=23) were made over a 3-yr period at North American boar studs and farms in which the primary complaint was sperm agglutination in association with decreased sperm longevity of extended semen, and increased regular returns to estrus and/or vaginal discharges across parity. Microscopic examination of extended semen from these units revealed depressed gross motility (usually semen collection and processing regardless of the semen extender used. The extended semen exhibited a high number of induced acrosome abnormalities (>20%). Sample pH was acidic (5.7 to 6.4) in 93% of the submitted samples. Aerobic culture yielded a variety of bacteria from different genera. A single bacterial contaminant was obtained from 66% of the submitted samples (n=37 doses); 34% contained 2 or more different bacterial genera. The most frequently isolated contaminant bacteria from porcine extended semen were Alcaligenes xylosoxydans (n=3), Burkholderia cepacia (n=6), Enterobacter cloacae (n=6), Escherichia coli (n=6), Serratia marcescens (n=5), and Stenotrophomonas [Xanthomonas] maltophilia (n=6); these 6 bacteria accounted for 71% of all contaminated samples, and were spermicidal when re-inoculated and incubated in fresh, high quality extended semen. All contaminant bacteria were found to be resistant to the aminoglycoside gentamicin, a common preservative antibiotic used in commercial porcine semen extenders. Eleven genera were spermicidal in conjunction with an acidic environment, while 2 strains (E. coli, S. maltophilia) were spermicidal without this characteristic acidic environment. Bacteria originated from multiple sources at the stud/farm, and were of animal and nonanimal origin. A minimum contamination technique (MCT) protocol was developed to standardize hygiene and sanitation. This protocol focused on MCT's during boar preparation, semen collection, semen processing and laboratory sanitation. Implementation of the MCT, in addition to specific recommendations

Diversity and functional properties of acid-tolerant bacteria isolated from tea plantation soil of Assam.

Science.gov (United States)

Goswami, Gunajit; Deka, Priyadarshini; Das, Pompi; Bora, Sudipta Sankar; Samanta, Ramkrishna; Boro, Robin Chandra; Barooah, Madhumita

2017-07-01

In this study, we report on the bacterial diversity and their functional properties prevalent in tea garden soils of Assam that have low pH (3.8-5.5). Culture-dependent studies and phospholipid fatty acid analysis revealed a high abundance of Gram-positive bacteria. Further, 70 acid-tolerant bacterial isolates characterized using a polyphasic taxonomy approach could be grouped to the genus Bacillus, Lysinibacillus, Staphylococcus, Brevundimonas, Alcaligenes, Enterobacter, Klebsiella, Escherichia, and Aeromonas. Among the 70 isolates, 47 most promising isolates were tested for their plant growth promoting activity based on the production of Indole Acetic Acid (IAA), siderophore, and HCN as well as solubilization of phosphate, zinc, and potassium. Out of the 47 isolates, 10 isolates tested positive for the entire aforesaid plant growth promoting tests and further tested for quantitative analyses for production of IAA, siderophore, and phosphate solubilization at the acidic and neutral condition. Results indicated that IAA and siderophore production, as well as phosphate solubilization efficiency of the isolates decreased significantly (P ≤ 0.05) in the acidic environment. This study revealed that low soil pH influences bacterial community structure and their functional properties.

Coupled cryoconite ecosystem structure-function relationships are revealed by comparing bacterial communities in alpine and Arctic glaciers

DEFF Research Database (Denmark)

Edwards, Arwyn; Mur, Luis A. J.; Girdwood, Susan E.

2014-01-01

Cryoconite holes are known as foci of microbial diversity and activity on polar glacier surfaces, but are virtually unexplored microbial habitats in alpine regions. In addition, whether cryoconite community structure reflects ecosystem functionality is poorly understood. Terminal restriction...... revealed Proteobacteria were particularly abundant, with Cyanobacteria likely acting as ecosystem engineers in both alpine and Arctic cryoconite communities. However, despite these generalities, significant differences in bacterial community structures, compositions and metabolomes are found between alpine...... fragment length polymorphism and Fourier transform infrared metabolite fingerprinting of cryoconite from glaciers in Austria, Greenland and Svalbard demonstrated cryoconite bacterial communities are closely correlated with cognate metabolite fingerprints. The influence of bacterial-associated fatty acids...

Development of a new lactic acid bacterial inoculant for fresh rice straw silage

Directory of Open Access Journals (Sweden)

Jong Geun Kim

2017-07-01

Full Text Available Objective Effects of newly isolated Lactobacillus plantarum on the fermentation and chemical composition of fresh rice straw silage was evaluated in this study. Methods Lactic acid bacteria (LAB from good crop silage were screened by growing them in MRS broth and a minimal medium with low carbohydrate content. Selected LAB (LAB 1821 were Gram-positive, rods, catalase negative, and were identified to be Lactobacillus plantarum based on their biochemical characteristics and a 16S rRNA analysis. Fresh rice straw was ensiled with two isolated LAB (1821 and 1841, two commercial inoculants (HM/F and P1132 and no additive as a control. Results After 2 months of storage at ambient temperature, rice straw silages treated with additives were well-preserved, the pH values and butyric and acetic acid contents were lower, and the lactic acid content and lactic/acetic acid ratio were higher than those in the control (p0.05 effect on acid detergent fiber or neutral detergent fiber contents. Crude protein (CP content and in vitro DM digestibility (IVDMD increased after inoculation of LAB 1821 (p<0.05. Conclusion LAB 1821 increased the CP, IVDMD, lactic acid content and ratio of lactic acid to acetic acid in rice straw silage and decreased the pH, acetic acid, NH3-N, and butyric acid contents. Therefore, adding LAB 1821 improved the fermentation quality and feed value of rice straw silage.

Bacterial meningitis

NARCIS (Netherlands)

Roos, Karen L.; van de Beek, Diederik

2010-01-01

Bacterial meningitis is a neurological emergency. Empiric antimicrobial and adjunctive therapy should be initiated as soon as a single set of blood cultures has been obtained. Clinical signs suggestive of bacterial meningitis include fever, headache, meningismus, vomiting, photophobia, and an

Effect of Fertilization on Tomato Bacterial Wilt Biocontrolling and Soil Health Restoration Using FAME Analysis

Institute of Scientific and Technical Information of China (English)

CAI Yan-fei; ZHAO Su-qing; LIAO Zong-wen; HE Cheng-xin; ZHUANG Xue-ying

2003-01-01

The effect of applying biological organic fertilizer (BOF) on bacterial wilt incidence of tomatoand soil microbial community under continuous cropping was studied. The results showed that all the tomatoeswere infected by bacterial wilt in the control. The infection rates of tomatoes in the treatments with un-com-posted BOF and decomposed BOF were 55 and 50% respectively. Fatty acid methyl esters (FAME) analysisindicated soil microbial community changed sensitively after applying BOF. Soil FAME total content, relativefungi content and ratio of fungi to bacteria were significantly increased in both BOF treatments. The soil odd-number fatty acid proportion changed after applying BOF, aC15: 0, iC17 . 0 decreased, while cyC17 . 0 in-creased in soil odd-number fatty acid proportion. BOF application would strengthen soil health and diseasesuppression. The content of C16: 111c in soil microbial community was obviously increased after decomposedBOF application. It indicated that the growth of AM fungi could be enhanced with decomposed BOF applica-tion. FAME microbial biomarkers could be used for an indicator of soil health and disease suppression. Odd-number fatty acid proportion was a sensitive indicator of the effect of applying un-composted and decomposedBOF respectively on soil health regulating.

Exogenous Polyunsaturated Fatty Acids Impact Membrane Remodeling and Affect Virulence Phenotypes among Pathogenic Vibrio Species.

Science.gov (United States)

Moravec, Anna R; Siv, Andrew W; Hobby, Chelsea R; Lindsay, Emily N; Norbash, Layla V; Shults, Daniel J; Symes, Steven J K; Giles, David K

2017-11-15

The pathogenic Vibrio species ( V. cholerae , V. parahaemolyticus , and V. vulnificus ) represent a constant threat to human health, causing foodborne and skin wound infections as a result of ingestion of or exposure to contaminated water and seafood. Recent studies have highlighted Vibrio 's ability to acquire fatty acids from environmental sources and assimilate them into cell membranes. The possession and conservation of such machinery provokes consideration of fatty acids as important factors in the pathogenic lifestyle of Vibrio species. The findings here link exogenous fatty acid exposure to changes in bacterial membrane phospholipid structure, permeability, phenotypes associated with virulence, and consequent stress responses that may impact survival and persistence of pathogenic Vibrio species. Polyunsaturated fatty acids (PUFAs) (ranging in carbon length and unsaturation) supplied in growth medium were assimilated into bacterial phospholipids, as determined by thin-layer chromatography and liquid chromatography-mass spectrometry. The incorporation of fatty acids variably affected membrane permeability, as judged by uptake of the hydrophobic compound crystal violet. For each species, certain fatty acids were identified as affecting resistance to antimicrobial peptide treatment. Significant fluctuations were observed with regard to both motility and biofilm formation following growth in the presence of individual PUFAs. Our results illustrate the important and complex roles of exogenous fatty acids in the membrane physiology and virulence of a bacterial genus that inhabits aquatic and host environments containing an abundance of diverse fatty acids. IMPORTANCE Bacterial responses to fatty acids include, but are not limited to, degradation for metabolic gain, modification of membrane lipids, alteration of protein function, and regulation of gene expression. Vibrio species exhibit significant diversity with regard to the machinery known to participate in the

Opioid Receptors Blockade Modulates Apoptosis in a Rat Model of ...

African Journals Online (AJOL)

inflammation characterized by replacement of liver tissue by ... Materials and Methods: Cirrhosis was induced in rats by bile duct ligation .... treated with deoxyribonucleic acid labeling solution containing ... binding was inhibited using non-immune serum. .... studies considering the increased level of tumor necrosis factor-α.

Protein Structure-sensitive Analysis by Normal Pulse Voltammetry

Czech Academy of Sciences Publication Activity Database

Černocká, Hana; Paleček, Emil

2016-01-01

Roč. 28, č. 11 (2016), s. 2884-2889 ISSN 1040-0397 R&D Projects: GA ČR(CZ) GA15-15479S Institutional support: RVO:68081707 Keywords : mercury -electrodes * deoxyribonucleic-acid * hydrogen evolution Subject RIV: BO - Biophysics Impact factor: 2.851, year: 2016

New aids for the non-invasive prenatal diagnosis of achondroplasia: dysmorphic features, charts of fetal size and molecular confirmation using cell-free fetal DNA in maternal plasma

NARCIS (Netherlands)

Chitty, L. S.; Griffin, D. R.; Meaney, C.; Barrett, A.; Khalil, A.; Pajkrt, E.; Cole, T. J.

2011-01-01

To improve the prenatal diagnosis of achondroplasia by constructing charts of fetal size, defining frequency of sonographic features and exploring the role of non-invasive molecular diagnosis based on cell-free fetal deoxyribonucleic acid (DNA) in maternal plasma. Data on fetuses with a confirmed

Extent of digestion affects the success of amplifying human DNA from blood meals of Anopheles gambiae (Diptera: Culicidae)

NARCIS (Netherlands)

Mukabana, W.R.; Takken, W.; Seda, P.; Killeen, G.F.; Hawley, W.A.; Knols, B.G.J.

2002-01-01

The success of distinguishing blood meal sources of Anopheles gambiae Giles through deoxyribonucleic acid (DNA) profiling was investigated by polymerase chain reaction (PCR) amplification at the TC-11 and VWA human short tandem repeats (STR) loci. Blood meal size and locus had no significant effect

Mur Ligase Inhibitors as Anti-bacterials: A Comprehensive Review.

Science.gov (United States)

Sangshetti, Jaiprakash N; Joshi, Suyog S; Patil, Rajendra H; Moloney, Mark G; Shinde, Devanand B

2017-01-01

Exploring a new target for antibacterial drug discovery has gained much attention because of the emergence of Multidrug Resistance (MDR) strains of bacteria. To overcome this problem the development of novel antibacterial was considered as highest priority task and was one of the biggest challenge since multiple factors were involved. The bacterial peptidoglycan biosynthetic pathway has been well documented in the last few years and has been found to be imperative source for the development of novel antibacterial agents with high target specificity as they are essential for bacterial survival and have no homologs in humans. We have therefore reviewed the process of peptidoglycan biosynthesis which involves various steps like formation of UDP-Nacetylglucosamine (GlcNAc), UDP-N-acetylmuramic acid (MurNAc) and lipid intermediates (Lipid I and Lipid II) which are controlled by various enzymes like GlmS, GlmM, GlmU enzyme, followed by Mur Ligases (MurAMurF) and finally by MraY and MurG respectively. These four amide ligases MurC-MurF can be used as the source for the development of novel multi-target antibacterial agents as they shared and conserved amino acid regions, catalytic mechanisms and structural features. This review begins with the need for novel antibacterial agents and challenges in their development even after the development of bacterial genomic studies. An overview of the peptidoglycan monomer formation, as a source of disparity in this process is presented, followed by detailed discussion of structural and functional aspects of all Mur enzymes and different chemical classes of their inhibitors along with their SAR studies and inhibitory potential. This review finally emphasizes on different patents and novel Mur inhibitors in the development phase. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Novel linear polymers able to inhibit bacterial quorum sensing.

Science.gov (United States)

Cavaleiro, Eliana; Duarte, Ana Sofia; Esteves, Ana Cristina; Correia, António; Whitcombe, Michael J; Piletska, Elena V; Piletsky, Sergey A; Chianella, Iva

2015-05-01

Bacterial phenotypes, such as biofilm formation, antibiotic resistance and virulence expression, are associated with quorum sensing. Quorum sensing is a density-dependent regulatory system of gene expression controlled by specific signal molecules, such as N-acyl homoserine lactones (AHLs), produced and released by bacteria. This study reports the development of linear polymers capable to attenuate quorum sensing by adsorption of AHLs. Linear polymers were synthesized using MMA as backbone monomer and methacrylic acid and itaconic acid as functional monomers. Two different quorum sensing-controlled phenotypes, Vibrio fischeri bioluminescence and Aeromonas hydrophila biofilm formation, were evaluated to test the polymers' efficiency. Results showed that both phenotypes were significantly affected by the polymers, with the itaconic acid-containing material being more effective than the methacrylic acid one. The polymer inhibitory effects were reverted by the addition of lactones, confirming attenuation of quorum sensing through sequestration of signal molecules. The polymers also showed no cytotoxicity when tested using a mammalian cell line. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bacterial utilization of size-fractionated dissolved organic matter

Digital Repository Service at National Institute of Oceanography (India)

Khodse, V.B.; Bhosle, N.B.

and vice versa (Amon et al. 2001, Goldberg et al. 2009). Similarly, utilization of uronic acid by heterotrophic bacteria has been reported in waters of the Bay of Bengal and the Gulf of Mexico (Hung et al. 2003, Khodse et al. 2007). In the coastal... in the Gulf of Mexico. Mar Chem 81:119-135 14 Jain A, Bhosle NB (2009) Biochemical composition of the marine conditioning film: implications for bacterial adhesion. Biofouling 25:13-19 Jorgensen NOG, Jensen RE (1994) Microbial fluxes of free...

Applying meta-pathway analyses through metagenomics to identify the functional properties of the major bacterial communities of a single spontaneous cocoa bean fermentation process sample.

Science.gov (United States)

Illeghems, Koen; Weckx, Stefan; De Vuyst, Luc

2015-09-01

A high-resolution functional metagenomic analysis of a representative single sample of a Brazilian spontaneous cocoa bean fermentation process was carried out to gain insight into its bacterial community functioning. By reconstruction of microbial meta-pathways based on metagenomic data, the current knowledge about the metabolic capabilities of bacterial members involved in the cocoa bean fermentation ecosystem was extended. Functional meta-pathway analysis revealed the distribution of the metabolic pathways between the bacterial members involved. The metabolic capabilities of the lactic acid bacteria present were most associated with the heterolactic fermentation and citrate assimilation pathways. The role of Enterobacteriaceae in the conversion of substrates was shown through the use of the mixed-acid fermentation and methylglyoxal detoxification pathways. Furthermore, several other potential functional roles for Enterobacteriaceae were indicated, such as pectinolysis and citrate assimilation. Concerning acetic acid bacteria, metabolic pathways were partially reconstructed, in particular those related to responses toward stress, explaining their metabolic activities during cocoa bean fermentation processes. Further, the in-depth metagenomic analysis unveiled functionalities involved in bacterial competitiveness, such as the occurrence of CRISPRs and potential bacteriocin production. Finally, comparative analysis of the metagenomic data with bacterial genomes of cocoa bean fermentation isolates revealed the applicability of the selected strains as functional starter cultures. Copyright © 2015 Elsevier Ltd. All rights reserved.

Culture-independent analysis of lactic acid bacteria diversity associated with mezcal fermentation.

Science.gov (United States)

Narváez-Zapata, J A; Rojas-Herrera, R A; Rodríguez-Luna, I C; Larralde-Corona, C P

2010-11-01

Mezcal is an alcoholic beverage obtained from the distillation of fermented juices of cooked Agave spp. plant stalks (agave must), and each region in Mexico with denomination of origin uses defined Agave species to prepare mezcal with unique organoleptic characteristics. During fermentation to produce mezcal in the state of Tamaulipas, not only alcohol-producing yeasts are involved, but also a lactic acid bacterial community that has not been characterized yet. In order to address this lack of knowledge on this traditional Mexican beverage, we performed a DGGE-16S rRNA analysis of the lactic acid bacterial diversity and metabolite accumulation during the fermentation of a typical agave must that is rustically produced in San Carlos County (Tamaulipas, Mexico). The analysis of metabolite production indicated a short but important malolactic fermentation stage not previously described for mezcal. The denaturing gradient gel electrophoresis (DGGE) analysis of the 16S rRNA genes showed a distinctive lactic acid bacterial community composed mainly of Pediococcus parvulus, Lactobacillus brevis, Lactobacillus composti, Lactobacillus parabuchneri, and Lactobacillus plantarum. Some atypical genera such as Weissella and Bacillus were also found in the residual must. Our results suggest that the lactic acid bacteria could strongly be implicated in the organoleptic attributes of this traditional Mexican distilled beverage.

Transport properties of poly(GACT)–poly(CTGA) deoxyribonucleic acid

Indian Academy of Sciences (India)

interface and the role of tube radius of nanotube contacts on the electronic transmission ... approaches, mostly use strictly one-dimensional tight-binding models [18–21] .... where ΣL(ΣR) is the self-energy matrix resulting from the coupling of the DNA .... where mα and mα run over the interfacial end-atoms of the SWNTs. gα.

The nature of radiolesions in deoxyribonucleic acid and their repair

International Nuclear Information System (INIS)

Moustacchi, E.

1976-01-01

The nature of different damages induced by ionizing radiations in DNA is described. The main lesions are single strand breaks, double strands breaks and base modifications. The principal enzymatic repair systems are recalled [fr

Reversible entrapment of plasmid deoxyribonucleic acid on different chromatographic supports.

Science.gov (United States)

Gabor, Boštjan; Černigoj, Urh; Barut, Miloš; Štrancar, Aleš

2013-10-11

HPLC based analytical assay is a powerful technique that can be used to efficiently monitor plasmid DNA (pDNA) purity and quantity throughout the entire purification process. Anion exchange monolithic and non-porous particle based stationary phases were used to study the recovery of the different pDNA isoforms from the analytical column. Three differently sized pDNA molecules of 3.0kbp, 5.2kbp and 14.0kbp were used. Plasmid DNA was injected onto columns under the binding conditions and the separation of the isoforms took place by increasing the ionic strength of the elution buffer. While there was no substantial decrease of the recovered supercoiled and linear isoforms of the pDNA with the increase of the plasmid size and with the increase of the flow rate (recoveries in all cases larger than 75%), a pronounced decrease of the oc isoform recovery was observed. The entrapment of the oc pDNA isoform occurred under non-binding conditions as well. The partial oc isoform elution from the column could be achieved by decreasing the flow rate of the elution mobile phase. The results suggested a reversible entrapment of the oc isoform in the restrictions within the pores of the monolithic material as well as within the intra-particle space of the non-porous particles. This phenomenon was observed on both types of the stationary phase morphologies and could only be connected to the size of a void space through which the pDNA needs to migrate. A prediction of reversible pDNA entrapment was successfully estimated with the calculation of Peclet numbers, Pe, which defines the ratio between a convective and diffusive mass transport. Copyright © 2013 Elsevier B.V. All rights reserved.

Host Specificity of Salmonella typhimurium Deoxyribonucleic Acid Restriction and Modification

Science.gov (United States)

Slocum, Harvey; Boyer, Herbert W.

1973-01-01

The restriction and modification genes of Salmonella typhimurium which lie near the thr locus were transferred to a restrictionless mutant of Escherichia coli. These genes were found to be allelic to the E. coli K, B, and A restriction and modification genes. E. coli recombinants with the restriction and modification host specificity of S. typhimurium restricted phage λ that had been modified by each of the seven known host specificities of E. coli at efficiency of plating levels of about 10−2. Phage λ modified with the S. typhimurium host specificity was restricted by six of the seven E. coli host specificities but not by the RII (fi− R-factor controlled) host specificity. It is proposed that the restriction and modification enzymes of this S. typhimurium host specificity have two substrates, one of which is a substrate for the RII host specificity enzymes. PMID:4570605

Purification of influenza deoxyribonucleic acid-based vaccine using agmatine monolith.

Science.gov (United States)

Bicho, D; Caramelo-Nunes, C; Sousa, A; Sousa, F; Queiroz, J A; Tomaz, C T

2016-02-15

Lately, researchers have made several efforts to improve vaccine production to fight highly contagious respiratory diseases like influenza. One of the most promising options for reducing the impact of this virus is DNA vaccination. However, a large quantity of highly pure plasmid DNA (pDNA) is necessary to attain this goal. The present work describes the production and purification of the plasmid NTC7482-41H-VA2HA expressing influenza virus hemagglutinin using an agmatine monolith. This ligand was chosen to purify supercoiled (sc) pDNA from complex lysates because of its versatile multimodal character. Its natural intervention in several biological systems together with its similarity with the highly studied arginine ligand allowed the development of a simpler and more specific purification process. Agmatine works under two strategies: descending ammonium sulfate gradient and ascending sodium chloride gradient. Furthermore, pH manipulation revealed an important role in pDNA isoforms selectivity. Dynamic binding capacity (DBC) experiments were performed varying different parameters and showed an increase with pDNA concentration, while high flow rate and high pH had the opposite effect. Sc pDNA was purified with high yield and was efficient with respect to cell transfection and cell viability. This monolith showed to be appropriate to purify the plasmid NTC7482-41H-VA2HA, providing a valuable tool for pDNA influenza vaccines preparation. Copyright © 2016. Published by Elsevier B.V.

Resistance of bacterial biofilms formed on stainless steel surface to disinfecting agent.

Science.gov (United States)

Królasik, Joanna; Zakowska, Zofia; Krepska, Milena; Klimek, Leszek

2010-01-01

The natural ability of microorganisms for adhesion and biofilm formation on various surfaces is one of the factors causing the inefficiency of a disinfection agent, despite its proven activity in vitro. The aim of the study was to determine the effectiveness of disinfecting substances on bacterial biofilms formed on stainless steel surface. A universally applied disinfecting agent was used in the tests. Bacterial strains: Listeria innocua, Pseudomonas putida, Micrococcus luteus, Staphylococcus hominis strains, were isolated from food contact surfaces, after a cleaning and disinfection process. The disinfecting agent was a commercially available acid specimen based on hydrogen peroxide and peroxyacetic acid, the substance that was designed for food industry usage. Model tests were carried out on biofilm formed on stainless steel (type 304, no 4 finish). Biofilms were recorded by electron scanning microscope. The disinfecting agent in usable concentration, 0.5% and during 10 minutes was ineffective for biofilms. The reduction of cells in biofilms was only 1-2 logarithmic cycles. The use of the agent in higher concentration--1% for 30 minutes caused reduction of cell number by around 5 logarithmic cycles only in the case of one microorganism, M. luteus. For other types: L. innocua, P. putida, S. hominis, the requirements placed on disinfecting agents were not fulfilled. The results of experiments proved that bacterial biofilms are resistant to the disinfectant applied in its operational parameters. Disinfecting effectiveness was achieved after twofold increase of the agent's concentration.

Bacterial Infections across the Ants: Frequency and Prevalence of Wolbachia, Spiroplasma, and Asaia

Directory of Open Access Journals (Sweden)

Stefanie Kautz

2013-01-01

Full Text Available Bacterial endosymbionts are common across insects, but we often lack a deeper knowledge of their prevalence across most organisms. Next-generation sequencing approaches can characterize bacterial diversity associated with a host and at the same time facilitate the fast and simultaneous screening of infectious bacteria. In this study, we used 16S rRNA tag encoded amplicon pyrosequencing to survey bacterial communities of 310 samples representing 221 individuals, 176 colonies and 95 species of ants. We found three distinct endosymbiont groups—Wolbachia (Alphaproteobacteria: Rickettsiales, Spiroplasma (Firmicutes: Entomoplasmatales, and relatives of Asaia (Alphaproteobacteria: Rhodospirillales—at different infection frequencies (at the ant species level: 22.1%, 28.4%, and 14.7%, resp. and relative abundances within bacterial communities (1.0%–99.9%. Spiroplasma was particularly enriched in the ant genus Polyrhachis, while Asaia relatives were most prevalent in arboreal ants of the genus Pseudomyrmex. While Wolbachia and Spiroplasma have been surveyed in ants before, Asaia, an acetic acid bacterium capable of fixing atmospheric nitrogen, has received much less attention. Due to sporadic prevalence across all ant taxa investigated, we hypothesize facultative associations for all three bacterial genera. Infection patterns are discussed in relation to potential adaptation of specific bacteria in certain ant groups.

The Role of Biotin in Bacterial Physiology and Virulence: a Novel Antibiotic Target for Mycobacterium tuberculosis.

Science.gov (United States)

Salaemae, Wanisa; Booker, Grant W; Polyak, Steven W

2016-04-01

Biotin is an essential cofactor for enzymes present in key metabolic pathways such as fatty acid biosynthesis, replenishment of the tricarboxylic acid cycle, and amino acid metabolism. Biotin is synthesized de novo in microorganisms, plants, and fungi, but this metabolic activity is absent in mammals, making biotin biosynthesis an attractive target for antibiotic discovery. In particular, biotin biosynthesis plays important metabolic roles as the sole source of biotin in all stages of the Mycobacterium tuberculosis life cycle due to the lack of a transporter for scavenging exogenous biotin. Biotin is intimately associated with lipid synthesis where the products form key components of the mycobacterial cell membrane that are critical for bacterial survival and pathogenesis. In this review we discuss the central role of biotin in bacterial physiology and highlight studies that demonstrate the importance of its biosynthesis for virulence. The structural biology of the known biotin synthetic enzymes is described alongside studies using structure-guided design, phenotypic screening, and fragment-based approaches to drug discovery as routes to new antituberculosis agents.

Soil microbial community responses to acid exposure and neutralization treatment.

Science.gov (United States)

Shin, Doyun; Lee, Yunho; Park, Jeonghyun; Moon, Hee Sun; Hyun, Sung Pil

2017-12-15

Changes in microbial community induced by acid shock were studied in the context of potential release of acids to the environment due to chemical accidents. The responses of microbial communities in three different soils to the exposure to sulfuric or hydrofluoric acid and to the subsequent neutralization treatment were investigated as functions of acid concentration and exposure time by using 16S-rRNA gene based pyrosequencing and DGGE (Denaturing Gradient Gel Electrophoresis). Measurements of soil pH and dissolved ion concentrations revealed that the added acids were neutralized to different degrees, depending on the mineral composition and soil texture. Hydrofluoric acid was more effectively neutralized by the soils, compared with sulfuric acid at the same normality. Gram-negative ß-Proteobacteria were shown to be the most acid-sensitive bacterial strains, while spore-forming Gram-positive Bacilli were the most acid-tolerant. The results of this study suggest that the Gram-positive to Gram-negative bacterial ratio may serve as an effective bio-indicator in assessing the impact of the acid shock on the microbial community. Neutralization treatments helped recover the ratio closer to their original values. The findings of this study show that microbial community changes as well as geochemical changes such as pH and dissolved ion concentrations need to be considered in estimating the impact of an acid spill, in selecting an optimal remediation strategy, and in deciding when to end remedial actions at the acid spill impacted site. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis of thermoplastic starch-bacterial cellulose nanocomposites via in situ fermentation

OpenAIRE

Osorio, Marlon A.; Restrepo, David; Velásquez-Cock, Jorge A.; Zuluaga, Robin O.; Montoya, Ursula; Rojas, Orlando; Gañán, Piedad F.; Marin, Diana; Castro, Cristina I.

2014-01-01

In this paper, a nanocomposite based on thermoplastic starch (TPS) reinforced with bacterial cellulose (BC) nanoribbons was synthesized by in situ fermentation and chemical crosslinking. BC nanoribbons were produced by a Colombian native strain of Gluconacetobacter medellinensis; the nanocomposite was plasticized with glycerol and crosslinked with citric acid. The reinforcement percentage in the nanocomposites remained constant throughout the fermentation time because of the TPS absorption ca...

21 CFR 864.7280 - Factor V Leiden DNA mutation detection systems.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Factor V Leiden DNA mutation detection systems....7280 Factor V Leiden DNA mutation detection systems. (a) Identification. Factor V Leiden deoxyribonucleic acid (DNA) mutation detection systems are devices that consist of different reagents and...

21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Drug metabolizing enzyme genotyping system. 862... Test Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification. A drug metabolizing enzyme genotyping system is a device intended for use in testing deoxyribonucleic acid (DNA...

Identification of Meconopsis species by a DNA barcode sequence ...

African Journals Online (AJOL)

Deoxyribonucleic acid (DNA) barcoding is a novel technology that uses a standard DNA sequence to facilitate species identification. Species identification is necessary for the authentication of traditional plant based medicines. Although a consensus has not been agreed regarding which DNA sequences can be used as ...

Different patterns of gene expression in rice varieties undergoing a ...

African Journals Online (AJOL)

Some genes specifically up-regulated in infected 9804-Rxo1 were defenserelated, including the genes encoding pathogenesis-related protein, terpene synthase family, transcription factors (TFs) AP2 domain containing protein, myb-like deoxyribonucleic acid (DNA)- binding domain containing protein, and C2H2-type ...

Report of foliar necrosis of potato caused by Cochliobolus lunatus in ...

African Journals Online (AJOL)

During the winter season of 2011, Cochliobolus lunatus was isolated from necrotized leaves of potato in potato plantations of Burdwan District, West Bengal State, India. The isolate was identified using standard monographs and taxonomic keys and confirmed molecularly using the Ribosomal Deoxyribonucleic acid (rDNA) ...

Golden rain tree leaf extracts as potential inhibitor of lipid ...

African Journals Online (AJOL)

This study was designed to evaluate the peroxyl radical scavenging capacity and deoxyribonucleic acid (DNA) protective effect of extract/fractions of Koelreuteria paniculata Laxm. (Golden rain tree) in lipid peroxidation assay and calf thymus DNA protection assay. The leaves of the plant were extracted with different ...

Is DNA Alive? a Study of Conceptual Change through Targeted Instruction

Science.gov (United States)

Witzig, Stephen B.; Freyermuth, Sharyn K.; Siegel, Marcelle A.; Izci, Kemal; Pires, J. Chris

2013-01-01

We are involved in a project to incorporate innovative assessments within a reform-based large-lecture biochemistry course for nonmajors. We not only assessed misconceptions but purposefully changed instruction throughout the semester to confront student ideas. Our research questions targeted student conceptions of deoxyribonucleic acid (DNA)…

Comparison of bacterial and fungal communities between natural and planted pine forests in subtropical China.

Science.gov (United States)

Nie, Ming; Meng, Han; Li, Ke; Wan, Jia-Rong; Quan, Zhe-Xue; Fang, Chang-Ming; Chen, Jia-Kuan; Li, Bo

2012-01-01

To improve our understanding of the changes in bacterial and fungal diversity in natural pine and planted forests in subtropical region of China, we examined bacterial and fungal communities from a native and a nearby planted pine forest of the Mt. Lushan by constructing clone libraries of 16S and 18S rRNA genes. For bacterial communities, Proteobacteria and Acidobacteria were dominant bacterial taxa in both two types of forest soils. The Shannon-Wiener diversity index, rarefaction curve analysis, and LibShuff analysis suggest that these two forests contained similar diversity of bacterial communities. Low soil acidity (pH ≈ 4) of our study forests might be one of the most important selection factors determining growth of acidophilic Acidobacteria and Proteobacteria. However, the natural forest harbored greater level of fungal diversity than the planted forest according to the Shannon-Wiener diversity index and rarefaction curve analysis. Basidiomycota and Ascomycota were dominant fungal taxa in the soils of natural and planted forests, respectively. Our results suggest that fungal community was more sensitive than the bacterial community in characterizing the differences in plant cover impacts on the microbial flora in the natural and planted forests. The natural and planted forests may function differently due to the differences in soil fungal diversity and relative abundance.

Wood Ash Induced pH Changes Strongly Affect Soil Bacterial Numbers and Community Composition

DEFF Research Database (Denmark)

Bang-Andreasen, Toke; Nielsen, Jeppe T.; Voriskova, Jana

2017-01-01

Recirculation of wood ash from energy production to forest soil improves the sustainability of this energy production form as recycled wood ash contains nutrients that otherwise would be lost at harvest. In addition, wood-ash is beneficial to many soils due to its inherent acid......-neutralizing capabilities. However, wood ash has several ecosystem-perturbing effects like increased soil pH and pore water electrical conductivity both known to strongly impact soil bacterial numbers and community composition. Studies investigating soil bacterial community responses to wood ash application remain sparse...... and the available results are ambiguous and remain at a general taxonomic level. Here we investigate the response of bacterial communities in a spruce forest soil to wood ash addition corresponding to 0, 5, 22, and 167 t wood ash ha(-1). We used culture-based enumerations of general bacteria, Pseudomonas...

Amplicon sequencing for the quantification of spoilage microbiota in complex foods including bacterial spores

NARCIS (Netherlands)

Boer, de P.; Caspers, M.; Sanders, J.W.; Kemperman, R.; Wijman, J.; Lommerse, G.; Roeselers, G.; Montijn, R.; Abee, T.; Kort, R.

2015-01-01

Background
Spoilage of food products is frequently caused by bacterial spores and lactic acid bacteria. Identification of these organisms by classic cultivation methods is limited by their ability to form colonies on nutrient agar plates. In this study, we adapted and optimized 16S rRNA amplicon

Nanomaterials from bacterial cellulose for antimicrobial wound dressing

Science.gov (United States)

Liyaskina, E.; Revin, V.; Paramonova, E.; Nazarkina, M.; Pestov, N.; Revina, N.; Kolesnikova, S.

2017-01-01

Bacterial nanocellulose (BNC) is widely used in biomedical applications. BNC has attracted increasing attention as a novel wound dressing material, but it has no antimicrobial activity. To get over this problem in the present study the BNC was saturated with antibiotic fusidic acid (FA). The subject of the experiment was BNC, produced by bacteria Gluconacetobacter sucrofermentans B-11267. The resulting biocomposites have high antibiotic activity against Staphylococcus aureus and can be used in medicine as a wound dressing. The structure of BNC was analyzed by atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR).

Culturable endophytic bacterial communities associated with field-grown soybean.

Science.gov (United States)

de Almeida Lopes, K B; Carpentieri-Pipolo, V; Oro, T H; Stefani Pagliosa, E; Degrassi, G

2016-03-01

Assess the diversity of the culturable endophytic bacterial population associated with transgenic and nontransgenic soybean grown in field trial sites in Brazil and characterize them phenotypically and genotypically focusing on characteristics related to plant growth promotion. Endophytic bacteria were isolated from roots, stems and leaves of soybean cultivars (nontransgenic (C) and glyphosate-resistant (GR) transgenic soybean), including the isogenic BRS133 and BRS245RR. Significant differences were observed in bacterial densities in relation to genotype and tissue from which the isolates were obtained. The highest number of bacteria was observed in roots and in GR soybean. Based on characteristics related to plant growth promotion, 54 strains were identified by partial 16S rRNA sequence analysis, with most of the isolates belonging to the species Enterobacter ludwigii and Variovorax paradoxus. Among the isolates, 44·4% were able to either produce indoleacetic acid (IAA) or solubilize phosphates, and 9·2% (all from GR soybean) presented both plant growth-promoting activities. The results from this study indicate that the abundance of endophytic bacterial communities of soybean differs between cultivars and in general it was higher in the transgenic cultivars than in nontransgenic cultivars. BRS 245 RR exhibited no significant difference in abundance compared to nontransgenic BRS133. This suggests that the impact of the management used in the GR soybean fields was comparable with the impacts of some enviromental factors. However, the bacterial endophytes associated to GR and nontransgenic soybean were different. The soybean-associated bacteria showing characteristics related to plant growth promotion were identified as belonging to the species Pantoea agglomerans and Variovorax paradoxus. Our study demonstrated differences concerning compostion of culturable endophytic bacterial population in nontransgenic and transgenic soybean. © 2016 The Society for Applied

Haematoxylin and eosin staining identifies medium to large bacterial aggregates with a reliable specificity: A comparative analysis of follicular bacterial aggregates in axillary biopsies using peptide nucleic acid-fluorescence in situ hybridization and haematoxylin and eosin staining

DEFF Research Database (Denmark)

Ring, Hans Christian; Riis, Peter Theut; Bay, Lene

2017-01-01

between bacterial aggregates identified by haematoxylin and eosin (HE) staining vs bacterial aggregates in corresponding PNA-FISH samples. Axillary biopsies were obtained in 24 healthy controls. HE-stained and PNA-FISH samples were investigated using traditional light microscopy and CLSM, respectively....... The data demonstrate that HE staining identifies large bacterial aggregates (>10 μm) with a sensitivity of 0.43 and specificity of 1. The methods, however, are not equivalent as demonstrated by a McNemar's test (P=.04). Where bacterial aggregates >10 μm in diameter, HE staining may offer a rapid...... and practical low-cost tool to evaluate bacterial aggregates....

A new strategy to enhance polysialic acid production by controlling ...

African Journals Online (AJOL)

Polysialic acid (PSA) is a new pharmaceutical material used in control release of protein drugs and as scaffold material in biomedical applications. It is also a vital source of sialic acid and its derivatives. In this paper, we demonstrated that the substrate sorbitol has significant effect on bacterial growth and PSA formation in ...

Evaluation of in-situ fatty acid extraction protocols for the analysis of staphylococcal cell membrane associated fatty acids by gas chromatography.

Science.gov (United States)

Crompton, Marcus J; Dunstan, R Hugh

2018-05-01

The composition and integrity of the bacterial cytoplasmic membrane is critical to the survival of staphylococci in dynamic environments and it is important to investigate how the cell membrane responds to changes in the environmental conditions. The staphylococcal membrane differs from eukaryotic and many other bacterial cell membranes by having a high abundance of branch fatty acids and relatively few unsaturated fatty acids. The range of available methods for extraction and efficient analyses of staphylococcal fatty acids was initially appraised to identify the best potential procedures for appraisal. Staphylococcus aureus subsp. aureus Rosenbach (ATCC® 29213) was grown under optimal conditions to generate a cell biomass to compare the efficiencies of three approaches to extract and prepare methyl esters of the membrane fatty acids: (1) acidic direct transesterification of lipids, (2) modified basic direct transesterification of membrane lipids with adjusted reaction times and temperatures, and (3) base catalysed hydrolysis followed by acid catalysed esterification in two separate chemical reactions (MIDI process). All methods were able to extract fatty acids from the cell mass effectively where these lipids represented approximately 5% of the cellular dry mass. The acidic transesterification method had the least number of steps, the lowest coefficient of variation at 6.7% and good resistance to tolerating water. Basic transesterification was the least accurate method showing the highest coefficient of variation (26%). The MIDI method showed good recoveries, but had twice the number of steps and a coefficient of variation of 16%. It was also found that there was no need to use an anti-oxidant such as BHT for the protection of polyunsaturated fatty acids when the GC-MS injection liner was clean. It was concluded that the acidic transesterification procedures formed the most efficient and reproducible method for the analyses of staphylococcal membrane fatty acids

Bacterial lung abscess

International Nuclear Information System (INIS)

Groskin, S.A.; Panicek, D.M.; Ewing, D.K.; Rivera, F.; Math, K.; Teixeira, J.; Heitzman, E.R.

1987-01-01

A retrospective review of patients with bacterial lung abscess was carried out. Demographic, clinical, and radiographical features of this patient group are compared with similar data from patients with empyema and/or cavitated lung carcinoma; differential diagnostic points are stressed. The entity of radiographically occult lung abscess is discussed. Complications associated with bacterial lung abscess are discussed. Current therapeutic options and treatment philosophy for patients with bacterial lung abscess are noted

Bacterial growth on macrophyte leachate and fate of bacterial production

International Nuclear Information System (INIS)

Findlay, S.; Carlough, L.; Crocker, M.T.; Gill, H.K.; Meyer, J.L.; Smith, P.J.

1986-01-01

The role bacteria play in transferring organic carbon to other trophic levels in aquatic ecosystems depends on the efficiency with which they convert dissolved organic [ 14 C]-labelled carbon into bacterial biomass and on the ability of consumers to graze bacteria. The authors have measured the conversion efficiency for bacteria growing on macrophyte-derived dissolved organic carbon and estimated the amount of bacterial production removed by grazing. Bacteria converted this DOC into new tissue with an efficiency of 53%, substantially higher than the apparent conversion efficiency of macrophyte-derived particulate organic carbon or other types of DOC. Two estimates of grazing indicate that the decline in bacterial numbers after the bloom was probably due to grazing by flagellates. These results show the significance of the bacterial link between DOC and other trophic levels

Enhanced Antibacterial Activity of Ent-Labdane Derivatives of Salvic Acid (7α-Hydroxy-8(17)-ent-Labden-15-Oic Acid): Effect of Lipophilicity and the Hydrogen Bonding Role in Bacterial Membrane Interaction.

Science.gov (United States)

Echeverría, Javier; Urzúa, Alejandro; Sanhueza, Loreto; Wilkens, Marcela

2017-06-23

In the present study, the antibacterial activity of several ent -labdane derivatives of salvic acid (7α-hydroxy-8(17)- ent -labden-15-oic acid) was evaluated in vitro against the Gram-negative bacterium Escherichia coli and the Gram-positive bacteria Staphylococcus aureus and Bacillus cereus . For all of the compounds, the antibacterial activity was expressed as the minimum inhibitory concentration (MIC) in liquid media and minimum inhibitory amount (MIA) in solid media. Structure activity relationships (SAR) were employed to correlate the effect of the calculated lipophilicity parameters (logP ow ) on the inhibitory activity. Employing a phospholipidic bilayer (POPG) as a bacterial membrane model, ent -labdane-membrane interactions were simulated utilizing docking studies. The results indicate that (i) the presence of a carboxylic acid in the C-15 position, which acted as a hydrogen-bond donor (HBD), was essential for the antibacterial activity of the ent -labdanes; (ii) an increase in the length of the acylated chain at the C-7 position improved the antibacterial activity until an optimum length of five carbon atoms was reached; (iii) an increase in the length of the acylated chain by more than five carbon atoms resulted in a dramatic decrease in activity, which completely disappeared in acyl chains of more than nine carbon atoms; and (iv) the structural factors described above, including one HBD at C-15 and a hexanoyloxi moiety at C-7, had a good fit to a specific lipophilic range and antibacterial activity. The lipophilicity parameter has a predictive characteristic feature on the antibacterial activity of this class of compounds, to be considered in the design of new biologically active molecules.

Structure and Orientation of Bovine Lactoferrampin in the Mimetic Bacterial Membrane as Revealed by Solid-State NMR and Molecular Dynamics Simulation

Science.gov (United States)

Tsutsumi, Atsushi; Javkhlantugs, Namsrai; Kira, Atsushi; Umeyama, Masako; Kawamura, Izuru; Nishimura, Katsuyuki; Ueda, Kazuyoshi; Naito, Akira

2012-01-01

Bovine lactoferrampin (LFampinB) is a newly discovered antimicrobial peptide found in the N1-domain of bovine lactoferrin (268–284), and consists of 17 amino-acid residues. It is important to determine the orientation and structure of LFampinB in bacterial membranes to reveal the antimicrobial mechanism. We therefore performed 13C and 31P NMR, 13C-31P rotational echo double resonance (REDOR), potassium ion-selective electrode, and quartz-crystal microbalance measurements for LFampinB with mimetic bacterial membrane and molecular-dynamics simulation in acidic membrane. 31P NMR results indicated that LFampinB caused a defect in mimetic bacterial membranes. Ion-selective electrode measurements showed that ion leakage occurred for the mimetic bacterial membrane containing cardiolipin. Quartz-crystal microbalance measurements revealed that LFampinB had greater affinity to acidic phospholipids than that to neutral phospholipids. 13C DD-MAS and static NMR spectra showed that LFampinB formed an α-helix in the N-terminus region and tilted 45° to the bilayer normal. REDOR dephasing patterns between carbonyl carbon nucleus in LFampinB and phosphorus nuclei in lipid phosphate groups were measured by 13C-31P REDOR and the results revealed that LFampinB is located in the interfacial region of the membrane. Molecular-dynamics simulation showed the tilt angle to be 42° and the rotation angle to be 92.5° for Leu3, which are in excellent agreement with the experimental values. PMID:23083717

Withania somnifera attenuates acid production, acid tolerance and extra-cellular polysaccharide formation of Streptococcus mutans biofilms.

Science.gov (United States)

Pandit, Santosh; Song, Kwang-Yeob; Jeon, Jae-Gyu

2014-01-01

Withania somnifera (Ashwagandha) is a plant of the Solanaceae family. It has been widely used as a remedy for a variety of ailments in India and Nepal. The plant has also been used as a controlling agent for dental diseases. The aim of the present study was to evaluate the activity of the methanol extract of W. somnifera against the physiological ability of cariogenic biofilms and to identify the components of the extract. To determine the activity of the extract, assays for sucrose-dependent bacterial adherence, glycolytic acid production, acid tolerance, and extracellular polysaccharide formation were performed using Streptococcus mutans biofilms. The viability change of S. mutans biofilms cells was also determined. A phytochemical analysis of the extract was performed using TLC and LC/MS/MS. The extract showed inhibitory effects on sucrose-dependent bacterial adherence (≥ 100 μg/ml), glycolytic acid production (≥ 300 μg/ml), acid tolerance (≥ 300 μg/ml), and extracellular polysaccharide formation (≥ 300 μg/ml) of S. mutans biofilms. However, the extract did not alter the viability of S. mutans biofilms cells in all concentrations tested. Based on the phytochemical analysis, the activity of the extract may be related to the presence of alkaloids, anthrones, coumarines, anthraquinones, terpenoids, flavonoids, and steroid lactones (withanolide A, withaferin A, withanolide B, withanoside IV, and 12-deoxy withastramonolide). These data indicate that W. somnifera may be a potential agent for restraining the physiological ability of cariogenic biofilms.

Bacterial population dynamics during the ensiling of Medicago sativa (alfalfa) and subsequent exposure to air.

Science.gov (United States)

McGarvey, J A; Franco, R B; Palumbo, J D; Hnasko, R; Stanker, L; Mitloehner, F M

2013-06-01

To describe, at high resolution, the bacterial population dynamics and chemical transformations during the ensiling of alfalfa and subsequent exposure to air. Samples of alfalfa, ensiled alfalfa and silage exposed to air were collected and their bacterial population structures compared using 16S rRNA gene libraries containing approximately 1900 sequences each. Cultural and chemical analyses were also performed to complement the 16S gene sequence data. Sequence analysis revealed significant differences (P alfalfa-derived library contained mostly sequences associated with the Gammaproteobacteria (including the genera: Enterobacter, Erwinia and Pantoea); the ensiled material contained mostly sequences associated with the lactic acid bacteria (LAB) (including the genera: Lactobacillus, Pediococcus and Lactococcus). Exposure to air resulted in even greater percentages of LAB, especially among the genus Lactobacillus, and a significant drop in bacterial diversity. In-depth 16S rRNA gene sequence analysis revealed significant bacterial population structure changes during ensiling and again during exposure to air. This in-depth description of the bacterial population dynamics that occurred during ensiling and simulated feed out expands our knowledge of these processes. © 2013 The Society for Applied Microbiology No claim to US Government works.

Bacterial and fungal markers in tobacco smoke

Energy Technology Data Exchange (ETDEWEB)

Szponar, B., E-mail: szponar@iitd.pan.wroc.pl [Lund University, Dept. of Laboratory Medicine, Soelvegatan 23, 223 62 Lund (Sweden); Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Rudolfa Weigla 12, 53-114 Wroclaw (Poland); Pehrson, C.; Larsson, L. [Lund University, Dept. of Laboratory Medicine, Soelvegatan 23, 223 62 Lund (Sweden)

2012-11-01

Previous research has demonstrated that cigarette smoke contains bacterial and fungal components including lipopolysaccharide (LPS) and ergosterol. In the present study we used gas chromatography-mass spectrometry to analyze tobacco as well as mainstream and second hand smoke for 3-hydroxy fatty acids (3-OH FAs) of 10 to 18 carbon chain lengths, used as LPS markers, and ergosterol, used as a marker of fungal biomass. The air concentrations of LPS were 0.0017 nmol/m{sup 3} (N = 5) and 0.0007/m{sup 3} (N = 6) in the smoking vs. non-smoking rooms (p = 0.0559) of the studied private houses, and 0.0231 nmol/m{sup 3} (N = 5) vs. 0.0006 nmol/m{sup 3} (N = 5) (p = 0.0173), respectively, at the worksite. The air concentrations of ergosterol were also significantly higher in rooms with ongoing smoking than in rooms without smoking. A positive correlation was found between LPS and ergosterol in rooms with smoking but not in rooms without smoking. 3-OH C14:0 was the main 3-OH FA, followed by 3-OH C12:0, both in mainstream and second hand smoke and in phenol:water smoke extracts prepared in order to purify the LPS. The Limulus activity of the phenolic phase of tobacco was 3900 endotoxin units (EU)/cigarette; the corresponding amount of the smoke, collected on filters from 8 puffs, was 4 EU/cigarette. Tobacco smoking has been associated with a range of inflammatory airway conditions including COPD, asthma, bronchitis, alveolar hypersensitivity etc. Significant levels of LPS and ergosterol were identified in tobacco smoke and these observations support the hypothesis that microbial components of tobacco smoke contribute to inflammation and airway disease. -- Highlights: Black-Right-Pointing-Pointer Air concentration of bacterial and fungal markers is significantly higher in rooms with ongoing smoking than without smoking. Black-Right-Pointing-Pointer Bacterial LPS correlates with fungal marker in rooms with ongoing smoking but not without smoking. Black-Right-Pointing-Pointer LPS

Uterine bacterial flora in postpartum Danish Holstein dairy cows determined using DNA-based fingerprinting: Correlation to uterine condition and calving management

DEFF Research Database (Denmark)

Elkjær, K.; Ancker, M.-L.; Gustafsson, H.

2013-01-01

The overall aim of this study was to describe uterine bacterial flora during the postpartum period in Danish Holstein cows using the Terminal Restriction Fragment Length Polymorphism (T-RFLP) method. This method produces a pattern of nucleic acid fragments from the microorganisms present, reflect......The overall aim of this study was to describe uterine bacterial flora during the postpartum period in Danish Holstein cows using the Terminal Restriction Fragment Length Polymorphism (T-RFLP) method. This method produces a pattern of nucleic acid fragments from the microorganisms present......, reflecting the “fingerprint” of the actual microbial flora. As well as characterizing changes in flora with time from calving and between herds, data were examined for strong relations between uterine bacterial flora, calving management and uterine condition. In total 125 Holstein cows from five herds were...... included, and for each cow calving management was recorded. Cows were clinically examined on average 8 (range 0–19) and 28 (range 22–38) days after calving, and a uterine sample was taken for bacterial identification using T-RFLP. Milk samples were taken weekly for progesterone analysis. Bacteria were...

BACTERIAL CONSORTIUM

Directory of Open Access Journals (Sweden)

Payel Sarkar

2013-01-01

Full Text Available Petroleum aromatic hydrocarbons like benzen e, toluene, ethyl benzene and xylene, together known as BTEX, has almost the same chemical structure. These aromatic hydrocarbons are released as pollutants in th e environment. This work was taken up to develop a solvent tolerant bacterial cons ortium that could degrade BTEX compounds as they all share a common chemical structure. We have isolated almost 60 different types of bacterial strains from different petroleum contaminated sites. Of these 60 bacterial strains almost 20 microorganisms were screene d on the basis of capability to tolerate high concentration of BTEX. Ten differe nt consortia were prepared and the compatibility of the bacterial strains within the consortia was checked by gram staining and BTEX tolerance level. Four successful mi crobial consortia were selected in which all the bacterial strains concomitantly grew in presence of high concentration of BTEX (10% of toluene, 10% of benzene 5% ethyl benzene and 1% xylene. Consortium #2 showed the highest growth rate in pr esence of BTEX. Degradation of BTEX by consortium #2 was monitored for 5 days by gradual decrease in the volume of the solvents. The maximum reduction observed wa s 85% in 5 days. Gas chromatography results also reveal that could completely degrade benzene and ethyl benzene within 48 hours. Almost 90% degradation of toluene and xylene in 48 hours was exhibited by consortium #2. It could also tolerate and degrade many industrial solvents such as chloroform, DMSO, acetonitrile having a wide range of log P values (0.03–3.1. Degradation of aromatic hydrocarbon like BTEX by a solvent tolerant bacterial consortium is greatly significant as it could degrade high concentration of pollutants compared to a bacterium and also reduces the time span of degradation.

Making Worms Glow

Indian Academy of Sciences (India)

Permanent link: http://www.ias.ac.in/article/fulltext/reso/023/03/0291-0298. Keywords. Nanotechnology, nanomachines, I-switch, FRET, fluorophore, endocytosis, pH sensor, C.elegans. Abstract. Deoxyribonucleic acid (DNA) is the molecule that carries geneticinformation in a cell. The field of DNA nanotechnologyaims to use ...

Preventing Ultraviolet Light-Induced Damage: The Benefits of Antioxidants

Science.gov (United States)

Yip, Cheng-Wai

2007-01-01

Extracts of fruit peels contain antioxidants that protect the bacterium "Escherichia coli" against damage induced by ultraviolet light. Antioxidants neutralise free radicals, thus preventing oxidative damage to cells and deoxyribonucleic acid. A high survival rate of UV-exposed cells was observed when grapefruit or grape peel extract was…

DNA-based population density estimation of black bear at northern ...

African Journals Online (AJOL)

The analysis of deoxyribonucleic acid (DNA) microsatellites from hair samples obtained by the non-invasive method of traps was used to estimate the population density of black bears (Ursus americanus eremicus) in a mountain located at the county of Lampazos, Nuevo Leon, Mexico. The genotyping of bears was ...

Nucleic Acid-Based Detection and Identification of Bacterial and Fungal Plant Pathogens - Final Report

Energy Technology Data Exchange (ETDEWEB)

Kingsley, Mark T.

2001-03-13

The threat to American interests from terrorists is not limited to attacks against humans. Terrorists might seek to inflict damage to the U.S. economy by attacking our agricultural sector. Infection of commodity crops by bacterial or fungal crop pathogens could adversely impact U.S. agriculture, either directly from damage to crops or indirectly from damage to our ability to export crops suspected of contamination. Recognizing a terrorist attack against U.S. agriculture, to be able to prosecute the terrorists, is among the responsibilities of the members of Hazardous Material Response Unit (HMRU) of the Federal Bureau of Investigation (FBI). Nucleic acid analysis of plant pathogen strains by the use of polymerase chain reaction (PCR) amplification techniques is a powerful method for determining the exact identity of pathogens, as well as their possible region of origin. This type of analysis, however, requires that PCR assays be developed specific to each particular pathogen strain, and analysis protocols developed that are specific to the particular instrument used for detection. The objectives of the work described here were threefold: 1) to assess the potential terrorist threat to U.S. agricultural crops, 2) to determine whether suitable assays exist to monitor that threat, and 3) where assays are needed for priority plant pathogen threats, to modify or develop those assays for use by specialists at the HMRU. The assessment of potential threat to U.S. commodity crops and the availability of assays for those threats were described in detail in the Technical Requirements Document (9) and will be summarized in this report. This report addresses development of specific assays identified in the Technical Requirements Document, and offers recommendations for future development to ensure that HMRU specialists will be prepared with the PCR assays they need to protect against the threat of economic terrorism.

Bacterial surface adaptation

Science.gov (United States)

Utada, Andrew

2014-03-01

Biofilms are structured multi-cellular communities that are fundamental to the biology and ecology of bacteria. Parasitic bacterial biofilms can cause lethal infections and biofouling, but commensal bacterial biofilms, such as those found in the gut, can break down otherwise indigestible plant polysaccharides and allow us to enjoy vegetables. The first step in biofilm formation, adaptation to life on a surface, requires a working knowledge of low Reynolds number fluid physics, and the coordination of biochemical signaling, polysaccharide production, and molecular motility motors. These crucial early stages of biofilm formation are at present poorly understood. By adapting methods from soft matter physics, we dissect bacterial social behavior at the single cell level for several prototypical bacterial species, including Pseudomonas aeruginosa and Vibrio cholerae.

Synthesis and characterization of anti-bacterial and anti-fungal citrate-based mussel-inspired bioadhesives

Science.gov (United States)

Guo, Jinshan; Wang, Wei; Hu, Jianqing; Xie, Denghui; Gerhard, Ethan; Nisic, Merisa; Shan, Dingying; Qian, Guoying; Zheng, Siyang; Yang, Jian

2016-01-01

Bacterial and fungal infections in the use of surgical devices and medical implants remain a major concern. Traditional bioadhesives fail to incorporate anti-microbial properties, necessitating additional anti-microbial drug injection. Herein, by the introduction of the clinically used and inexpensive anti-fungal agent, 10-undecylenic acid (UA), into our recently developed injectable citrate-based mussel-inspired bioadhesives (iCMBAs), a new family of anti-bacterial and anti-fungal iCMBAs (AbAf iCs) was developed. AbAf iCs not only showed strong wet tissue adhesion strength, but also exhibited excellent in vitro cyto-compatibility, fast degradation, and strong initial and considerable long-term anti-bacterial and anti-fungal ability. For the first time, the biocompatibility and anti-microbial ability of sodium metaperiodate (PI), an oxidant used as a cross-linking initiator in the AbAf iCs system, was also thoroughly investigated. Our results suggest that the PI-based bioadhesives showed better anti-microbial properties compared to the unstable silver-based bioadhesive materials. In conclusion, AbAf iCs family can serve as excellent anti-bacterial and anti-fungal bioadhesive candidates for tissue/wound closure, wound dressing, and bone regeneration, especially when bacterial or fungal infections are a major concern. PMID:26874283

Estimating bacterial production in marine waters from the simultaneous incorporation of thymidine and leucine.

Science.gov (United States)

Chin-Leo, G; Kirchman, D L

1988-08-01

We examined the simultaneous incorporation of [H]thymidine and [C]leucine to obtain two independent indices of bacterial production (DNA and protein syntheses) in a single incubation. Incorporation rates of leucine estimated by the dual-label method were generally higher than those obtained by the single-label method, but the differences were small (dual/single = 1.1 +/- 0.2 [mean +/- standard deviation]) and were probably due to the presence of labeled leucyl-tRNA in the cold trichloroacetic acid-insoluble fraction. There were no significant differences in thymidine incorporation between dual- and single-label incubations (dual/ single = 1.03 +/- 0.13). Addition of the two substrates in relatively large amounts (25 nM) did not apparently increase bacterial activity during short incubations (leucine incorporation rates covaried over depth profiles of the Chesapeake Bay. Estimates of bacterial production based on thymidine and leucine differed by less than 25%. Although the need for appropriate conversion factors has not been eliminated, the dual-label approach can be used to examine the variation in bacterial production while ensuring that the observed variation in incorporation rates is due to real changes in bacterial production rather than changes in conversion factors or introduction of other artifacts.

Quantification of a bacterial secondary metabolite by SERS combined with SLM extraction for bioprocess monitoring

DEFF Research Database (Denmark)

Morelli, Lidia; Andreasen, Sune Zoëga; Jendresen, Christian Bille

2017-01-01

and combined it with surface enhanced Raman scattering (SERS) sensing for the screening of a biological process, namely for the quantification of a bacterial secondary metabolite, p-coumaric acid (pHCA), produced by Escherichia coli. The microfluidic device proved to be robust and reusable, enabling efficient...... removal of interfering compounds from the real samples, reaching more than 13-fold up-concentration of the donor at 10 μL min-1 flow rate. With this method, we quantified pHCA directly from the bacterial supernatant, distinguishing between various culture conditions based on the pHCA production yield...

Thioacetamide-induced changes in the body weight, kidney weight and the total nucleic acids content of kidney of mouse

International Nuclear Information System (INIS)

Shakoori, Abdul Rauf; Ashraf, Fauzia.

1976-01-01

Effects of thioacetamide (TAA) on the body weight, kidney weight and the total nucleic acids content of kidney of mouse were studied. TAA 1% and 2% solutions were injected intraperitoneally, twice with an interval of 24 hours in two different batches of male mice. In this way one batch received a total dose of 100 mg TAA/Kg body wt. while the other got a total dose of 200 mg TAA/Kg. Both the body as well as kidney weights decrease after TAA treatment. A total dose of 200 mg/Kg is a stronger inhibitor of growth as compared with that of 100 mg/Kg. The nucleic acids content show an increase after the drug treatment. The ribonucleic acid content of kidney increased from an average value of 4.30+0.14 mg/g kidney to 4.60+-0.22 mg/g kidney after 1% TAA treatment. The increase in 2% TAA treated mice is slightly more prominent. The deoxyribonucleic acid (DNA) content of kidney are likewise affected. After an initial increase in 1% TAA-treated animals, the DNA content gradually fall down to normal control values. Administration of 2% TAA solution causes an average increase of 21% i.e. from 1.93+-0.19 mg/g kidney wt to 2.26+-0.23 mg/g kidney wt. The size of cell, nucleus and nucleolus also increased after drug treatment, which mainly occurred during the first 24 hours of the post-treatment period

Bacterial colonization on coated and uncoated orthodontic wires: A prospective clinical trial.

Science.gov (United States)

Raji, Seyed Hamid; Shojaei, Hasan; Ghorani, Parinaz Saeidi; Rafiei, Elahe

2014-11-01

The advantages of coated orthodontic wires such as esthetic and their effects on reduced friction, corrosion and allergic reaction and the significant consequences of plaque accumulation on oral health encouraged us to assess bacterial colonization on these wires. A total of 18 (9 upper and 9 lower) epoxy resin coated 16 × 22 nickel-titanium wires (Spectra, GAC, USA) and 18 (9 upper and 9 lower) non-coated 16 × 22 nickel-titanium wires (Sentalloy, GAC, USA) with isolated packages were selected and sterilized before application. The samples were divided randomly between upper and lower arches in 18 patients and hence that every patient received one coated and one uncoated wire at the same time. Samples were removed and cut in equal lengths after 3 weeks and placed in phosphate buffered saline buffer. After separation of bacteria in trypsin and ethylenediaminetetraacetic acid solution, the diluted solution was cultured in blood agar and bacterial colony forming units were counted. Finally, the data was analyzed using the paired t-test and the significance was set at 0.05. Mean of bacterial colonization on uncoated wires was more than that of coated wires (P < 0.001). Bacterial plaque accumulation on epoxy resin coated nickel-titanium orthodontic wires is significantly lower than uncoated nickel-titanium wires.

Characteristics and crystal structure of bacterial inosine-5'-monophosphate dehydrogenase.

Energy Technology Data Exchange (ETDEWEB)

Zhang, R.; Evans, G.; Rotella, F. J.; Westbrook, E. M.; Beno, D.; Huberman, E.; Joachimiak, A.; Collart, F. R.

1999-01-01

IMP dehydrogenase (IMPDH) is an essential enzyme that catalyzes the first step unique to GTP synthesis. To provide a basis for the evaluation of IMPDH inhibitors as antimicrobial agents, we have expressed and characterized IMPDH from the pathogenic bacterium Streptococcus pyogenes. Our results show that the biochemical and kinetic characteristics of S. pyogenes IMPDH are similar to other bacterial IMPDH enzymes. However, the lack of sensitivity to mycophenolic acid and the K{sub m} for NAD (1180 {mu}M) exemplify some of the differences between the bacterial and mammalian IMPDH enzymes, making it an attractive target for antimicrobial agents. To evaluate the basis for these differences, we determined the crystal structure of the bacterial enzyme at 1.9 {angstrom} with substrate bound in the catalytic site. The structure was determined using selenomethionine-substituted protein and multiwavelength anomalous (MAD) analysis of data obtained with synchrotron radiation from the undulator beamline (19ID) of the Structural Biology Center at Argonne's Advanced Photon Source. S. pyogenes IMPDH is a tetramer with its four subunits related by a crystallographic 4-fold axis. The protein is composed of two domains: a TIM barrel domain that embodies the catalytic framework and a cystathione {beta}-synthase (CBS) dimer domain of so far unknown function. Using information provided by sequence alignments and the crystal structure, we prepared several site-specific mutants to examine the role of various active site regions in catalysis. These variants implicate the active site flap as an essential catalytic element and indicate there are significant differences in the catalytic environment of bacterial and mammalian IMPDH enzymes. Comparison of the structure of bacterial IMPDH with the known partial structures from eukaryotic organisms will provide an explanation of their distinct properties and contribute to the design of specific bacterial IMPDH inhibitors.

Minimal domain of bacterial phytochrome required for chromophore binding and fluorescence

Science.gov (United States)

Rumyantsev, Konstantin A.; Shcherbakova, Daria M.; Zakharova, Natalia I.; Emelyanov, Alexander V.; Turoverov, Konstantin K.; Verkhusha, Vladislav V.

2015-12-01

Fluorescent proteins (FP) are used to study various biological processes. Recently, a series of near-infrared (NIR) FPs based on bacterial phytochromes was developed. Finding ways to improve NIR FPs is becoming progressively important. By applying rational design and molecular evolution we have engineered R. palustris bacterial phytochrome into a single-domain NIR FP of 19.6 kDa, termed GAF-FP, which is 2-fold and 1.4-fold smaller than bacterial phytochrome-based NIR FPs and GFP-like proteins, respectively. Engineering of GAF-FP involved a substitution of 15% of its amino acids and a deletion of the knot structure. GAF-FP covalently binds two tetrapyrrole chromophores, biliverdin (BV) and phycocyanobilin (PCB). With the BV chromophore GAF-FP absorbs at 635 nm and fluoresces at 670 nm. With the PCB chromophore GAF-FP becomes blue-shifted and absorbs at 625 nm and fluoresces at 657 nm. The GAF-FP structure has a high tolerance to small peptide insertions. The small size of GAF-FP and its additional absorbance band in the violet range has allowed for designing a chimeric protein with Renilla luciferase. The chimera exhibits efficient non-radiative energy transfer from luciferase to GAF-FP, resulting in NIR bioluminescence. This study opens the way for engineering of small NIR FPs and NIR luciferases from bacterial phytochromes.

Remediation of grey forest soils heavily polluted with heavy metals by means of their leaching at acidic pH followed by the soil reclamation by means of neutralization and bacterial manure addition

Science.gov (United States)

Georgiev, Plamen; Groudev, Stoyan; Spasova, Irena; Nicolova, Marina

2014-05-01

Some grey forest soils in Western Bulgaria are heavily polluted with heavy metals (copper, lead, and zinc), arsenic, and uranium due to the infiltration of acid mine drainage generated at the abandoned uranium mine Curilo. This paper presents some results from a study about soil remediation based on the contaminants leaching from the topsoil by means of irrigation with solutions containing sulphuric acid or its in situ generation by means of sulphur-oxidizing chemolithotrophic bacteria in or without the presence of finely cut straw. These methods were tested in large scale zero suction lysimeters. The approaches based on S° and finely cut straw addition was the most efficient amongst the tested methods and for seven months of soil remediation the concentration of all soil contaminants were decreased below the relevant Maximum Admissible Concentration (MAC). Neutralization of the soil acidity was applied as a next stage of soil reclamation by adding CaCO3 and cow manure. As a result, soil pH increased from strongly acidic (2.36) to slightly acidic (6.15) which allowed subsequent addition of humic acids and bacterial manure to the topsoil. The soil habitat changed in this way facilitated the growth of microorganisms which restored the biogeochemical cycles of nitrogen and carbon to the levels typical for non-polluted grey forest soil.

Genome-wide identification of Streptococcus pneumoniae genes essential for bacterial replication during experimental meningitis

DEFF Research Database (Denmark)

Molzen, T E; Burghout, P; Bootsma, H J

2010-01-01

Meningitis is the most serious of invasive infections caused by the Gram-positive bacterium Streptococcus pneumoniae. Vaccines protect only against a limited number of serotypes, and evolving bacterial resistance to antimicrobials impedes treatment. Further insight into the molecular pathogenesis...... as targets for future therapy and prevention of pneumococcal meningitis, since their mutants were attenuated in both models of infection as well as in competitive growth in human cerebrospinal fluid in vitro.......Meningitis is the most serious of invasive infections caused by the Gram-positive bacterium Streptococcus pneumoniae. Vaccines protect only against a limited number of serotypes, and evolving bacterial resistance to antimicrobials impedes treatment. Further insight into the molecular pathogenesis...... genes mutants of which had become attenuated or enriched, respectively, during infection. The results point to essential roles for capsular polysaccharides, nutrient uptake, and amino acid biosynthesis in bacterial replication during experimental meningitis. The GAF phenotype of a subset of identified...

A Prebiotic Formula Improves the Gastrointestinal Bacterial Flora in Toddlers

Directory of Open Access Journals (Sweden)

Ya-Ling Chen

2016-01-01

Full Text Available We aimed to investigate the effect of enriched 3-prebiotic formula (including inulin, fructooligosaccharides, and galactooligosaccharides on toddler gut health by measuring fecal microbiota. Our results revealed that the consumption of 3-prebiotic formula three times per day giving total intake of 1.8 g prebiotic ingredients significantly showed the increased number of probiotic Bifidobacterium spp. colonies and the reduced populations of both C. perfringens and total anaerobic bacteria on the fecal bacterial flora in toddlers at 18~36 months. In addition, total organic acids in the fecal samples significantly increased which improves the utilization of bifidus under acidic conditions after consumption of the 3-prebiotic formula. Therefore, using the formula enriched with prebiotic may maintain gut health in toddlers.

Bacterial Protein-Tyrosine Kinases

DEFF Research Database (Denmark)

Shi, Lei; Kobir, Ahasanul; Jers, Carsten

2010-01-01

in exopolysaccharide production, virulence, DNA metabolism, stress response and other key functions of the bacterial cell. BY-kinases act through autophosphorylation (mainly in exopolysaccharide production) and phosphorylation of other proteins, which have in most cases been shown to be activated by tyrosine......Bacteria and Eukarya share essentially the same family of protein-serine/threonine kinases, also known as the Hanks-type kinases. However, when it comes to protein-tyrosine phosphorylation, bacteria seem to have gone their own way. Bacterial protein-tyrosine kinases (BY-kinases) are bacterial...... and highlighted their importance in bacterial physiology. Having no orthologues in Eukarya, BY-kinases are receiving a growing attention from the biomedical field, since they represent a particularly promising target for anti-bacterial drug design....

Proton pump inhibitor use and association with spontaneous bacterial peritonitis in patients with cirrhosis and ascites.

Science.gov (United States)

Siple, Jolene F; Morey, Jessica M; Gutman, Tracy E; Weinberg, Kathy L; Collins, Peggie D

2012-10-01

To evaluate the literature regarding the efficacy and safety of proton pump inhibitors (PPIs) when they are used in patients with cirrhosis and ascites. A literature search was conducted using MEDLINE (1966-May 2012) and Web of Science (1990-May 2012) with the terms proton pump inhibitor, antisecretory therapy, cirrhosis, ascites, spontaneous bacterial peritonitis, and Clostridium difficile. The search was restricted to articles published in English on the use of PPIs in humans. Reference citations from identified published articles were reviewed for relevant information. All articles in English identified from the data sources were evaluated for inclusion. One case series, 8 retrospective case-control trials, and 1 meta-analysis were identified. Cirrhosis may cause complications such as portal hypertension, esophageal varices, and ascites. Patients may be prescribed PPIs without clear indications or because of their propensity to develop upper gastrointestinal symptoms and bleeding. However, gastric acidity is a major nonspecific defense mechanism and there is insufficient evidence on the need for chronic acid suppression in patients with cirrhosis. It is postulated that the portal hypertensive environment in cirrhosis and the acid suppression from PPIs can increase the risk of spontaneous bacterial peritonitis and C. difficile infection in patients with cirrhosis with ascites. Several retrospective studies and 1 meta-analysis have confirmed this association. Patients with cirrhosis and ascites should be monitored carefully while on PPIs for a possible increased risk of infection from spontaneous bacterial peritonitis and C. difficile. Prospective randomized trials are needed to confirm this association. Clinicians should be aware of this lesser known adverse effect of PPIs.