Isolation, characterization, antibiogram and pathology of Pasteurella multocida isolated from pigs

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Mamta Tigga

2014-05-01

Full Text Available Aim: Isolation, characterization and antibiogram of Pasteurella multocida from diseased pigs of district Durg of Chhattisgarh, and to study pathological changes caused by swine pasteurellosis. Materials and Methods: An outbreak of swine pasteurellosis was suspected in pigs of Ruwabandha (Bhilai, Anjora, Somni, Tedesara, Tirgajhola villages of Durg district in Chhattisgarh, India during August and September of 2011. Nasal Swabs and blood samples from ailing pigs and heart blood and impression smears from morbid pigs were processed for detection and isolation of P. multocida by bacteriological methods. Detailed necropsy was conducted and gross and histopathological lesions were recorded. The test Isolates were subjected to antimicrobial sensitivity profile by disc-diffusion method. Results: The blood smears from heart blood and tissue impression smears revealed teaming of bipolar organisms indicating the presence of Pasteurella spp. The isolates obtained were subjected to Gram's staining for checking the purity and bipolar morphology and characterized biochemically. Gross lesions included severe acute pneumonia and haemorrhages in lungs, petechial haemorrhages on serous membranes and other visceral organs. On histopathological examination, lungs showed typical fibrinous bronchopneumonia, multifocal suppuration. All the isolates of P. multocida were 100% sensitive to Amoxicillin, Gentamicin, Enrofloxacin and showed100% resistance to Ceftizoxim and Cloxacillin. Conclusion: Gross and microscopic lesions in dead animals are of great diagnostic value and are of characteristic of P. multocida infection. Cultural, morphological and biochemical characters are useful to rule out the causative agent as P. multocida. Antibiotic sensitivity pattern of the isolates should routinely be carried out for knowing the antibiotic resistance trends in an endemic area.

Restriction endonuclease analysis of Pasteurella multocida isolates from three California turkey premises.

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Christiansen, K H; Carpenter, T E; Snipes, K P; Hird, D W; Ghazikhanian, G Y

1992-01-01

Three California turkey premises that had repeated outbreaks of fowl cholera were studied for periods of 2 to 4 years. Using biochemical, serologic, plasmid DNA, and restriction endonuclease analyses of isolates of Pasteurella multocida from turkeys and wildlife on the premises, strains of the organism were found to be enzootic on two of the premises. On the third, a variety of strains of P. multocida were isolated from fowl cholera outbreak flocks.

Revised description and classification of atypical isolates of Pasteurella multocida from bovine lungs based on genotypic characterization to include variants previously classified as biovar 2 of Pasteurella canis and Pasteurella avium

DEFF Research Database (Denmark)

Christensen, Henrik; Angen, Øystein; Olsen, John E.

2004-01-01

Strains deviating in key phenotypic characters, mainly isolated from cases of bovine pneumonia in five European countries, were genotyped in order to examine their genotypic relationship with Pasteurella multocida. Twenty-two strains of Pasteurella avium biovar 2, including variants in indole, xy...

Transmission of Pasteurella multocida on California turkey premises in 1988-89.

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Christiansen, K H; Carpenter, T E; Snipes, K P; Hird, D W

1992-01-01

Restriction endonuclease analysis (REA) of whole-cell DNA was used to determine possible sources of Pasteurella multocida for each outbreak of fowl cholera occurring in turkey flocks in eight commercial poultry companies in California from October 1988 to September 1989. Over this period, 179 isolates of P. multocida were obtained from dead turkeys in 80 meat and breeder flocks on 43 premises. P. multocida was isolated from wildlife on five premises. Isolates were characterized by subspecies, serotype, presence of plasmid DNA, and REA type. In 52 (65%) flocks, all isolates of P. multocida had the same REA pattern as the M9 live vaccine strain following digestion of DNA with the restriction enzyme SmaI. Field strains of P. multocida were obtained from 27 (34%) flocks, and one flock (1%) yielded both M9 and a field strain of the organism. REA of field strains of P. multocida revealed 17 different SmaI REA types. Based on matching SmaI REA types, potential sources of P. multocida were identified for 15 of the 28 flocks infected with field strains of the organism, and transmission between turkey premises was a possibility in only seven flocks.

Host Response in Rabbits to Infection with Pasteurella multocida Serogroup F Strains Originating from Fowl Cholera

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The ability of two avian Pasteurella multocida serogroup F strains to induce disease in rabbits was investigated in this study. Two groups of 18 Pasteurella-free rabbits each were intranasally challenged with strains isolated from chicken and turkey, respectively. Half the animals in each challenge ...

Utilization of L-aspartate, L-malate and fumarate by Pasteurella multocida

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Hoefer, M.; Flossmann, K.D. (Akademie der Landwirtschaftswissenschaften der DDR, Jena. Inst. fuer Bakterielle Tierseuchenforschung)

1981-01-01

Strains of Pasteurella multocida use L-aspartate, L-malate and furmarate, respectively, as substrates for production of succinic acid which accumulates in the medium. As was established by studies with /sup 14/C- and /sup 3/H-labelled substrates, the degradation of these substances proceeds analogously via the citric acid cycle.

Utilization of L-aspartate, L-malate and fumarate by Pasteurella multocida

International Nuclear Information System (INIS)

Hoefer, M.; Flossmann, K.D.

1981-01-01

Strains of Pasteurella multocida use L-aspartate, L-malate and furmarate, respectively, as substrates for production of succinic acid which accumulates in the medium. As was established by studies with 14 C- and 3 H-labelled substrates, the degradation of these substances proceeds analogously via the citric acid cycle. (author)

The pathogenesis of Pasteurella multocida local isolates in mice and chicken

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Supar

2000-03-01

Full Text Available Avian cholera or fowl cholera is a bacterial disease caused by Pasteurella multocida strain of serogroup A, has been recognized as important disease in domestic poultry such as ducks and chicken. P. multocida strains derived from overseas and local isolates are stored as freeze dried and kept at the Research hlstitute for Veterinary Science (BALITVET culture collection (BCC. Some of those bacteria are still alive and can be used as vaccine candidates. Each strain or isolate was activated in brain heart infusion broth containing foetal calf serum and incubated at 37°C then it was identitied by biochemical reactions. Field surveys Were conducted in Central Java and South Kalimantan to observe fowl cholera problems and sample collections for isolation of pathogens. Of the 14 of Pasteurella multocida strains or isolates from BCC, II strains (9 imported 2 local isolates were still alive. In addition to this 2 isolates trom chicken and duck were viable. Seven out of 9 imported strains killed mice within 3 x 24 hours, similarly for the local isolates (BCC 299, 2331, DYI, DY2, 12TG, 15TG. However, the only BCC 2331 and DY2 isolates were able to kill two week old chicken witIlin 6 x 24 hours post inoculation. From this experiment indicated that the P. multocida local isolates (BCC 2,331 and DY2 are more pathogenic than that of imported strains. Two strains of imported P. multocida BCC 2331, 1362 and 6 local isolates (BCC 299, 2331, DYI, DY2, 12TG and 15TG would be selected for mono- and polyvalent vaccine candidates in the following experiments and the highly patogenic BCC 2331 and DY2 isolates would be used to challenge the vaccinated animals.

Cross protection against fowl cholera disease with the use of recombinant Pasteurella multocida FHAB2 peptides vaccine

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It has been demonstrated that fhaB2 (filamentous hemagglutinin) is an important virulence factor for P. multocida in development of fowl cholera disease and that recombinant FHAB2 peptides derived from P. multocida, Pm-1059, protect turkeys against Pm-1059 challenge. To test the hypothesis that rFHA...

Plasmid DNA Analysis of Pasteurella multocida Serotype B isolated from Haemorrhagic Septicaemia outbreaks in Malaysia

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Jamal, H.

2005-01-01

Full Text Available A total of 150 purified isolates of Pasteurella multocida serotype B were used (Salmah, 2004 for plasmid DNA curing experiment to determine hyaluronidase activity, antibiotic resistance pattern (ARP and mice lethality test (LD50 for their role of pathogenicity. A plasmid curing experiment was carried out by using the intercalating agent; ethidium bromide and rifampicin, where it was found all the plasmids had been cured (plasmidless from Pasteurella multocida. All of these plasmidless isolates maintained their phenotypic characteristics. They showed the same antibiotic resistancepattern as before curing, produced hyaluronidase and possessed lethality activity in mice when injected intraperitoneally(i.p. Based on this observation, the antibiotic resistance, hyaluronidase activity and mice virulence could probably be chromosomal-mediated. Plasmids were detected 100% in all P. multocida isolates with identical profile of 2 plasmids size 3.0 and 5.5 kb. No large plasmids could be detected in all isolates. Since all the isolates appeared to have identicalplasmid profiles, they were subjected to restriction enzyme(RE analysis. From RE analysis results obtained, it can be concluded that the plasmid DNA in serotype B isolates are identical. Only 4 of 32 REs were found to cleave these plasmids with identical restriction fingerprints; BglII, HaeIII, RsaI and SspI. From RE analysis results, it can be concluded that the plasmid DNA isolates are identical. This plasmid might not played any role in pathogenicity of Pasteurella multocida serotype B, however this information is important for the construction of shuttle vectors in genetic studies of the pathogenicity of haemorrhagic septicaemia(HS.

Pneumonia in calves produced with aerosols of Pasteurella multocida alone and in combination with bovine herpesvirus 1.

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Jericho, K W; Carter, G R

1985-01-01

Pathological changes in respiratory tracts were studied in 30 calves following exposure to aerosols of Pasteurella multocida or to bovine herpesvirus 1 and P. multocida. Two groups of five calves were exposed to aerosols of one of two types of P. multocida only, which produced lobar pneumonia in one calf of each group. Another five groups of four calves were exposed to aerosols of bovine herpesvirus 1 and four to seven days later to one of the two types or one sub-type of P. multocida. Extens...

Pasteurella multocida Involved in Respiratory Disease of Wild Chimpanzees

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Köndgen, Sophie; Leider, Michaela; Lankester, Felix; Bethe, Astrid; Lübke-Becker, Antina; Leendertz, Fabian H.; Ewers, Christa

2011-01-01

Pasteurella multocida can cause a variety of diseases in various species of mammals and birds throughout the world but nothing is known about its importance for wild great apes. In this study we isolated P. multocida from wild living, habituated chimpanzees from Taï National Park, Côte d'Ivoire. Isolates originated from two chimpanzees that died during a respiratory disease outbreak in 2004 as well as from one individual that developed chronic air-sacculitis following this outbreak. Four isolates were subjected to a full phenotypic and molecular characterisation. Two different clones were identified using pulsed field gel electrophoresis. Multi Locus Sequence Typing (MLST) enabled the identification of previous unknown alleles and two new sequence types, ST68 and ST69, were assigned. Phylogenetic analysis of the superoxide dismutase (sodA) gene and concatenated sequences from seven MLST-housekeeping genes showed close clustering within known P. multocida isolated from various hosts and geographic locations. Due to the clinical relevance of the strains described here, these results make an important contribution to our knowledge of pathogens involved in lethal disease outbreaks among endangered great apes. PMID:21931664

Ducks as a potential reservoir for Pasteurella multocida infection detected using a new rOmpH-based ELISA.

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Liu, Rongchang; Chen, Cuiteng; Cheng, Longfei; Lu, Ronghui; Fu, Guanghua; Shi, Shaohua; Chen, Hongmei; Wan, Chunhe; Lin, Jiansheng; Fu, Qiuling; Huang, Yu

2017-07-28

Pasteurella multocida is an important pathogen of numerous domestic poultry and wild animals and is associated with a variety of diseases including fowl cholera. The aim of this study was to develop an indirect enzyme-linked immunosorbent assay (ELISA) based on recombinant outer-membrane protein H (rOmpH) for detection of anti-P. multocida antibodies in serum to determine their prevalence in Chinese ducks. The P. multocida ompH gene was cloned into pET32a, and rOmpH was expressed in Escherichia coli BL21 (DE3). Western blotting revealed that purified rOmpH was recognized by duck antisera against P. multocida, and an indirect ELISA was established. During analysis of serum samples (n=115) from ducks, the rOmpH ELISA showed 95.0% specificity, 100% sensitivity and a 92.0% κ coefficient (95% confidence interval 0.844-0.997) as compared with a microtiter agglutination test. Among 165 randomly selected serum samples, which were collected in 2015 and originated from six duck farms across Fujian Province, China, anti-P. multocida antibodies were detected in 22.42% of apparently healthy ducks, including 25 of 90 sheldrakes (27.8%), eight of 50 Peking ducks (16.0%) and four of 25 Muscovy ducks (16%). Overall, the data suggest that rOmpH is a suitable candidate antigen for the development of an indirect ELISA for detection of P. multocida in ducks; moreover, our results showed that ducks could serve as a potential reservoir for P. multocida infection.

Comparative genome analysis of an avirulent and two virulent strains of avian Pasteurella multocida reveals candidate genes involved in fitness and pathogenicity

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Fowl cholera is a highly contagious systemic disease affecting wild and domestic birds, frequently resulting in high morbidity and mortality. The causative agent is Pasteurella multocida (P. multocida). The completed genome of P. multocida strain Pm70 has been available for over eleven years and has...

Antimicrobial susceptibility of Pasteurella multocida and Haemophilus parasuis isolates associated with porcine pneumonia

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Kateřina Nedbalcová

2013-01-01

Full Text Available Pasteurella multocida and Haemophilus parasuis pig isolates obtained in the Czech Republic were tested for their susceptibility against selected antimicrobial agents by broth microdilution method between 2008 and 2011. A low degree of resistance was observed for ampicillin, amoxicillin/clavulanic acid, ceftiofur, tulathromycin, tilmicosin, florfenicol and enrofloxacin in 20 (6.0%, 15 (4.5 %, 2 (0.6%, 8 (2.4%, 13 (3.9%, 5 (1.5% and 5 (1.5% P. multocida isolates as well as for tiamulin, gentamicin, tulathromycin, tilmicosin and ampicillin in 2 (2.4%, 2 (2.4%, 3 (3.6%, 3 (3.6% and 6 (7.2% H. parasuis isolates. In addition, moderate level of resistance to tiamulin was found in 60 (18.1% P. multocida isolates and high level of resistance for tetracycline was detected in 107 (32.2 % P. multocida isolates and in 23 (27.7 % H. parasuis isolates. Differences between resistance rates of P. multocida and H. parasuis were significant (P ≤ 0.5 only for tiamulin. These data confirmed that antimicrobial resistance is not very widespread among current porcine P. multocida and H. parasuis isolates in the Czech Republic.

Characterization of sucrose-negative Pasteurella multocida variants, including isolates from large-cat bite wounds

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Christensen, Henrik Grimmig; Bisgaard, Magne; Angen, Øystein

2005-01-01

To validate the identification of Pasteurella multocida-like bacteria negative for acid formation from sucrose, including isolates from bite wounds caused by large cats, 17 strains were phenotypically and genotypically characterized. Phylogenetic analysis of partially sequenced rpoB and infB genes...... showed the monophyly of the strains characterized and the reference strains of P. multocida. The sucrose-negative strains formed two groups, one related to reference strains of P. multocida and the other related to a separate species-like group (taxon 45 of Bisgaard). DNA-DNA hybridization further...... and the reference strains of P. multocida. Two strains isolated from leopard bite wounds were related to the type strain of P. dagmatis; however, they represented a new taxon (taxon 46 of Bisgaard), in accordance with their distinct phenotypic and genotypic identifications. The present study documents that sucrose-negative...

Efforts Towards The Development Of Recombinant Vaccines Against

African Journals Online (AJOL)

ABSTRACT. Hemorrhagic septicemia is caused by gram-negative bacterium of Pasteurella multocida (P. multocida) strains. Most of the current vaccines against P. multocida have shortcomings. Presently, there is increasing efforts towards construction of recombinant clone for vaccine development against P. multocida.

Effect of aerial ammonia on porcine infection of the respiratory tract with toxigenic Pasteurella multocida

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Andreasen, Morten; Bækbo, P.; Nielsen, J.P.

1999-01-01

The objective of the experimental study was to examine whether aerial ammonia alone could predispose the respiratory system of pigs to infection with toxigenic Pasteurella multocida type A. Two groups of 5 pigs each were continuously exposed to 50 ppm ammonia and less than 5 ppm ammonia...

Associations between water quality, Pasteurella multocida, and avian cholera at Sacramento National Wildlife Refuge

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Lehr, M.A.; Botzler, R.G.; Samuel, M.D.; Shadduck, D.J.

2005-01-01

We studied patterns in avian cholera mortality, the presence of Pasteurella multocida in the water or sediment, and water chemistry characteristics in 10 wetlands at the Sacramento National Wildlife Refuge Complex (California, USA), an area of recurrent avian cholera epizootics, during the winters of 1997 and 1998. Avian cholera outbreaks (a?Y50 dead birds) occurred on two wetlands during the winter of 1997, but no P. multocida were recovered from 390 water and 390 sediment samples from any of the 10 wetlands. No mortality events were observed on study wetlands during the winter of 1998; however, P. multocida was recovered from water and sediment samples in six of the 10 study wetlands. The pH levels were higher for wetlands experiencing outbreaks during the winter of 1997 than for nonoutbreak wetlands, and aluminum concentrations were higher in wetlands from which P. multocida were recovered during the winter of 1998. Water chemistry parameters (calcium, magnesium, sodium, and dissolved protein) previously linked with P. multocida and avian cholera mortality were not associated with the occurrence of avian cholera outbreaks or the presence of P. multocida in our study wetlands. Overall, we found no evidence to support the hypothesis that wetland characteristics facilitate the presence of P. multocida and, thereby, allow some wetlands to serve as long-term sources (reservoirs) for P. multocida.

Efforts towards the development of recombinant Vaccines against ...

African Journals Online (AJOL)

Hemorrhagic septicemia is caused by gram-negative bacterium of Pasteurella multocida (P. multocida) strains. Most of the current vaccines against P. multocida have shortcomings. Presently, there is increasing efforts towards construction of recombinant clone for vaccine development against P. multocida. In this review an ...

The Capsule Is a Virulence Determinant in the Pathogenesis of Pasteurella multocida M1404 (B:2)

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Boyce, John D.; Adler, Ben

2000-01-01

Capsules from a range of pathogenic bacteria are key virulence determinants, and the capsule has been implicated in virulence in Pasteurella multocida. We have previously identified and determined the nucleotide sequence of the P. multocida M1404 (B:2) capsule biosynthetic locus (J. D. Boyce, J. Y. Chung, and B. Adler, Vet. Microbiol. 72:121–134, 2000). The cap locus consists of 15 genes, which can be grouped into three functional regions. Regions 1 and 3 contain genes proposed to encode prot...

Efficacy of a novel Pasteurella multocida vaccine against progressive atrophic rhinitis of swine

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Hsuan, Shih-Ling; Liao, Chih-Ming; Huang, Chienjin; Winton, James R.; Chen, Zeng-Weng; Lee, Wei-Cheng; Liao, Jiunn-Wang; Chen, Ter-Hsin; Chiou, Chwei-Jang; Yeh, Kuang-Sheng; Chien, Maw-Sheng

2009-01-01

The efficacy of a novel vaccine composed of three short recombinant subunit Pasteurella multocida toxin (PMT) proteins in combination with a bi-valent P. multocida whole-cell bacterin (rsPMT–PM) was evaluated in field studies for prevention and control of progressive atrophic rhinitis (PAR) of swine at 15 conventional farrow-to-finish farms. Experimental piglets that were immunized twice with the rsPMT–PM vaccine developed detectable titers of neutralizing antibodies (greater than 1:8) that prevented the growth retardation and pathological lesions typically observed following challenge with authentic PMT. A total of 542 sows were vaccinated once or twice prior to parturition and serum neutralizing antibody titers were evaluated. Both single and double vaccination protocols induced neutralizing antibody titers of 1:16 or higher in 62% and 74% of sows, respectively. Notably, neither sows nor piglets at a farm experiencing a severe outbreak of PAR at the time of the vaccination trial had detectable antibody titers, but antibody titers increased significantly to 1:16 or higher in 40% of sows following double vaccination. During the year after vaccination, clinical signs of PAR decreased in fattening pigs and growth performance improved sufficiently to reduce the rearing period until marketing by 2 weeks. Collectively, these results indicate that the rsPMT–PM vaccine could be used to provide protective immunity for controlling the prevalence and severity of PAR among farm-raised swine.

Virulence Genes and Antimicrobial Resistance Profiles of Pasteurella multocida Strains Isolated from Rabbits in Brazil

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Thais Sebastiana Porfida Ferreira

2012-01-01

Full Text Available Pasteurella multocida is responsible for a wide range of diseases in domestic animals. In rabbits, the agent is related to nasal discharge, pneumonia, otitis media, pyometra, orchitis, abscess, and septicemia. One hundred and forty rabbits with respiratory diseases from four rabbitries in São Paulo State, Brazil were evaluated for the detection of P. multocida in their nasal cavities. A total of twenty-nine animals were positive to P. multocida isolation, and 46 strains were selected and characterized by means of biochemical tests and PCR. P. multocida strains were tested for capsular type, virulence genes, and resistance profile. A total of 45.6% (21/46 of isolates belonged to capsular type A, and 54.34% (25/46 of the isolates were untypeable. None of the strains harboured toxA or pfhA genes. The frequency of the other twenty genes tested was variable, and the data generated was used to build a dendrogram, showing the relatedness of strains, which were clustered according to origin. Resistance revealed to be more common against sulfonamides and cotrimoxazole, followed by erythromycin, penicillin, and amoxicillin.

Lack of effect of aerial ammonia on atrophic rhinitis and pneumonia induced by Mycoplasma hyopneumoniae and toxigenic Pasteurella multocida

DEFF Research Database (Denmark)

Andreasen, Morten; Bækbo, P.; Nielsen, Jens

2000-01-01

The objective of this experimental study was to determine the effects of aerial ammonia on disease development and bacterial colonization in weaned pigs inoculated with toxigenic Pasteurella multocida and Mycoplasma hyopneumoniae. Two groups of 10 pigs each were continuously exposed to 50 and 100 p.......p.m ammonia, respectively, and compared to a non-exposed control, group of 20 pigs. Following aerosol inoculation with M. hyopneumoniae at day 9, ail pigs were aerosol-inoculated with toxigenic P. multocida type A at days 28, 42 and 56. Ac day 63 they were euthanized. Clinical signs including coughing...... with inoculations with M. hyopneumoniae and toxigenic P. multocida had no significant effect on disease development, but may have enhanced colonization by toxigenic P. multocida on the nasal turbinates....

Anatomopathological pneumonic aspects associated with highly pathogenic Pasteurella multocida in finishing pigs

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Eliana S. Paladino

Full Text Available ABSTRACT: The bacterium Pasteurella multocida is a frequent cause of porcine respiratory disease complex in finishing pigs. Historically, the bacterium is recognized as an opportunistic agent, causing secondary bacterial pneumonia in pigs. Several Brazilian reports have suggested the ability of P. multocida to cause primary pulmonary infection that leads to the death of finishing pigs prior to slaughter. The aim of this study was to evaluate anatomopathological pulmonary findings associated with P. multocida infection that were obtained from animals with clinical respiratory disease and from animals at slaughter. Twenty-five lung samples from 14 herds of finishing pigs with acute clinical respiratory disease and 19 lungs collected at slaughter from a different set of 14 herds were studied. In all lung samples, bacterial isolation was performed, and only samples with pure P. multocida growth were included in the study. Gross and histopathological lesions were evaluated, as well as Influenza A, porcine circovirus type 2 (PCV2 and Mycoplasma hyopneumoniae co-infections. Pleuritis and pericarditis were more often observed in clinical samples (P<0.05. Moreover, there was a numerical trend indicating that pericarditis, lymphadenomegaly and cavity exudates were more often present in clinical samples. Thirteen lung samples were negative to M. hyopneumoniae, Influenza A and PCV2 by immunohistochemistry (IHC, with only P. multocida identified. In these cases, gross lesions such as pleuritis, pericarditis and lymphadenomegaly were always present, and no histologic lesions indicative of other agents such as Actinobacillus pleuropneumoniae, Actinobacillus suis or Haemophilus parasuis were observed. These findings suggest the ability of some P. multocida isolates to cause primary respiratory and systemic infection. However, in this study, it was not possible to determine specific virulence markers to explain these findings.

Capsular Polysaccharide Interferes with Biofilm Formation by Pasteurella multocida Serogroup A

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Briana Petruzzi

2017-11-01

Full Text Available Pasteurella multocida is an important multihost animal and zoonotic pathogen that is capable of causing respiratory and multisystemic diseases, bacteremia, and bite wound infections. The glycosaminoglycan capsule of P. multocida is an essential virulence factor that protects the bacterium from host defenses. However, chronic infections (such as swine atrophic rhinitis and the carrier state in birds and other animals may be associated with biofilm formation, which has not been characterized in P. multocida. Biofilm formation by clinical isolates was inversely related to capsule production and was confirmed with capsule-deficient mutants of highly encapsulated strains. Capsule-deficient mutants formed biofilms with a larger biomass that was thicker and smoother than the biofilm of encapsulated strains. Passage of a highly encapsulated, poor-biofilm-forming strain under conditions that favored biofilm formation resulted in the production of less capsular polysaccharide and a more robust biofilm, as did addition of hyaluronidase to the growth medium of all of the strains tested. The matrix material of the biofilm was composed predominately of a glycogen exopolysaccharide (EPS, as determined by gas chromatography-mass spectrometry, nuclear magnetic resonance, and enzymatic digestion. However, a putative glycogen synthesis locus was not differentially regulated when the bacteria were grown as a biofilm or planktonically, as determined by quantitative reverse transcriptase PCR. Therefore, the negatively charged capsule may interfere with biofilm formation by blocking adherence to a surface or by preventing the EPS matrix from encasing large numbers of bacterial cells. This is the first detailed description of biofilm formation and a glycogen EPS by P. multocida.

Serotypes and DNA fingerprint profiles of Pasteurella multocida isolated from raptors

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Wilson, M.A.; Duncan, R.M.; Nordholm, G.E.; Berlowski, B.M.

1995-01-01

Pasteurella multocida isolates from 21 raptors were examined by DNA fingerprint profile and serotyping methods. Isolates were obtained from noncaptive birds of prey found in 11 states from November 28, 1979, through February 10, 1993. Nine isolates were from bald eagles, and the remaining isolates were from hawks, falcons, and owls. Seven isolates were members of capsule group A, and 14 were nonencapsulated. One isolate was identified as somatic type 3, and another was type 3,4,7; both had unique HhaI DNA fingerprint profiles. Nineteen isolates expressed somatic type 1 antigen; HhaI profiles of all type 1 isolates were identical to each other and to the HhaI profile of the reference somatic type 1, strain X-73. The 19 type 1 isolates were differentiated by sequential digestion of DNA with HpaII; four HpaII fingerprint profiles were obtained. The HpaII profile of one isolate was identical to the HpaII profile of strain X-73. Incidence of P. multocida somatic type 1 in raptors suggests that this type may be prevalent in other wildlife or wildlife environments.

Phenotypic and genotypic characters of isolates of Pasteurella multocida obtained from back-yard poultry and from two outbreaks of avian cholera in avifauna in Denmark

DEFF Research Database (Denmark)

Christensen, J.P.; Dietz, Hans-Henrik; Bisgaard, M.

1998-01-01

Two outbreaks of fowl cholera in the avifauna in Denmark, affecting primarily elders but also cormorants, gulls and oyster-catchers were shown to be caused by the same clone of Pasteurella multocida ssp, multocida by restriction enzyme analysis (REA) and ribotyping, using the enzymes HpaII and Hha...

Meningencefalite por Pasteurella multocida: estudo clínico-laboratorial de um caso em lactente

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C. E. Levy

1989-12-01

Full Text Available Os autores apresentam descrição clínico-laboratorial e evolutiva do caso de lactente com o diagnóstico de meningencefalite por Pasteurella multocida que apresentou na evolução atraso neuromotor, manifestações epilépticas, surdez neurossensorial e paresia crural à esquerda. Fazem também breve revisão do papel deste agente etiológico na patologia humana. Ressaltam a importância da P. multocida em casos de meningites bacterianas, fazendo-se o diagnóstico laboratorial diferencial com o Haemophilus influenzae e Neisseria meningitidis em processos infecciosos conseqüentes a arranhadura ou mordida de animais e nas bacteremias ou septicemias em pacientes com hepatopatias crônicas ou em estados de imunodepressão.

Multiplex PCR To Identify Macrolide Resistance Determinants in Mannheimia haemolytica and Pasteurella multocida

DEFF Research Database (Denmark)

Rose, Simon; Desmolaize, Benoit; Jaju, Puneet

2012-01-01

The bacterial pathogens Mannheimia haemolytica and Pasteurella multocida are major etiological agents in respiratory tract infections of cattle. Although these infections can generally be successfully treated with veterinary macrolide antibiotics, a few recent isolates have shown resistance...... to these drugs. Macrolide resistance in members of the family Pasteurellaceae is conferred by combinations of at least three genes: erm(42), which encodes a monomethyltransferase and confers a type I MLS(B) (macrolide, lincosamide, and streptogramin B) phenotype; msr(E), which encodes a macrolide efflux pump...

Variability of Pasteurella multocida isolated from Icelandic sheep and detection of the toxA gene.

Science.gov (United States)

Einarsdottir, Thorbjorg; Gunnarsson, Eggert; Sigurdardottir, Olof G; Jorundsson, Einar; Fridriksdottir, Vala; Thorarinsdottir, Gudridur E; Hjartardottir, Sigridur

2016-09-01

Pasteurella multocida can be part of the upper respiratory flora of animals, but under conditions of stress or immunocompromisation, the bacteria can cause severe respiratory symptoms. In this study, we compared 10 P. multocida isolates from Icelandic sheep with respiratory symptoms and 19 isolates from apparently healthy abattoir sheep. We examined capsule type, genetic variability and the presence of the toxA gene in the two groups. Surprisingly, we found that all ovine P. multocida isolates examined in this study carried the toxA gene, which markedly differs from what has been published from other studies. Interestingly, all isolates from abattoir animals were capsule type D, whilst bacteria isolated from animals with clinical respiratory symptoms had capsule type A, D or F. Examination of seven housekeeping genes indicated that the clinical respiratory isolates were significantly more heterogeneous than the abattoir isolates (P<0.05, two-tailed Mann-Whitney U test). The results suggest that there may be at least two groups of P. multocida in sheep - a genetically homogeneous group that resides in the respiratory tract and a genetically heterogeneous group that is the predominant cause of disease.

Comparison of standardised versus non-standardised methods for testing the in vitro potency of oxytetracycline against mannheimia haemolytica and pasteurella multocida

OpenAIRE

Lees, P; Illambas, J; Pelligand, L; Toutain, P L

2016-01-01

The in vitro pharmacodynamics of oxytetracycline was established for six isolates of each of the calf pneumonia pathogens Mannheimia haemolytica and Pasteurella multocida. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and bacterial time-kill curves were determined in two matrices, Mueller Hinton broth (MHB) and calf serum. Geometric mean MIC ratios, serum:MHB, were 25.2:1 (M. haemolytica) and 27.4:1 (P. multocida). The degree of binding of oxytetracycline to...

A novel Erm monomethyltransferase in antibiotic-resistant isolates of Mannheimia haemolytica and Pasteurella multocida

DEFF Research Database (Denmark)

Desmolaize, Benoit; Rose, Simon; Warrass, Ralf

2011-01-01

Mannheimia haemolytica and Pasteurella multocida are aetiological agents commonly associated with respiratory tract infections in cattle. Recent isolates of these pathogens have been shown to be resistant to macrolides and other ribosome-targeting antibiotics. Direct analysis of the 23S r...... without any dimethyltransferase activity. Erm(42) is a novel addition to the Erm family: it is phylogenetically distant from the other Erm family members and it is unique in being a bona fide monomethyltransferase that is disseminated between bacterial pathogens....

Isolation, characterization, virulence and immunogenicity testing of field isolates of Pasteurella multocida, Staphylococcus aureus, and Streptococcus agalactiae in laboratory settings.

Science.gov (United States)

Qudratullah; Muhammad, G; Saqib, M; Bilal, M Qamar

2017-08-01

The present study was designed to investigate isolation, characterization, virulence and immunogenicity testing of field isolates of Pasteurella multocida, Staphylococcus aureus, and Streptococcus agalactiae in rabbits and mice. Isolates of P. multocida, S. aureus and Str. agalactiae recovered from field cases of Hemorragic septicemia and mastitis were scrutinized for virulence/pathogenicity and immunogenicity. Mouse LD 50 of P. multocida showed that P. multocida isolate No.1 was more virulent than isolates No. 2 and 3. Virulence of isolate No.1S. aureus and Str. agalactiae revealed that 100, 80% rabbits died within 18h of inoculation. Seven-digit numerical profiles of these 4 isolates with API ® Staph test strips isolates, No.1 (6736153) showed good identification (S. aureus id=90.3%). Indirect ELISA-based serum antibody titers to P. multocida isolate No.1, S. aureus No.1, Str. agalactiae, isolate No.1 elicited high antibody titers 1.9, 1.23, 1.12 respectively. All the pathogens of Isolate No. 1 (P. multocida, S. aureus Str. agalactiae), were high antibody than others isolates. Copyright © 2017 Elsevier B.V. All rights reserved.

Isolation and Identification of Pasteurella multocida from Sheep & Goat in Iran

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Valadan, M.,

2014-05-01

Full Text Available This study has been carried out with the objective of isolation and identification of agent(s of pasteurella pneumonia in sheep and goat in Iran using bacteriological and biochemical assays to be identified in the pursuant researches to be used in pasteurellosis vaccine production. To accomplish this objective, samples were gathered from areas suspicious to pasteurellosis infection and industrial abbatoirs according to clinical and autopsy symptoms from eight provinces of Bushehr, Esfahan, Kerman, Kohgilooyeh & Boyr Ahmad, Fars, Qom, Tehran and Qazvin in a period from spring 2008 to spring 2011. Samples were different in sort due to the existent condition but generally were comprised of palatine tonsil swabs or blood samples taken from jugular vein in live animals and lungs or upper respiratory tract lymph glands in dead or slaughtered animals. Totally, 1454 samples (1120 samples of sheep, 334 samples of goat composed if 1084 samples of live animals and 370 samples of dead or slaughterd animals were tested. Considering results obtained from assays, only 54 samples (3.71% were assessed as being pasteurella, genus of which was totally identified as multocida.

Why your housecat's trite little bite could cause you quite a fright: a study of domestic felines on the occurrence and antibiotic susceptibility of Pasteurella multocida.

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Freshwater, A

2008-10-01

Approximately four to five million animal bite wounds are reported in the USA each year. Domestic companion animals inflict the majority of these wounds. Although canine bites far outnumber feline bites, unlike the dog, the cat's bite is worse than its bark; 20-80% of all cat bites will become infected, compared with only 3-18% of dog bite wounds. Pasteurella multocida is the most commonly cultured bacterium from infected cat bite wounds. Anyone seeking medical attention for a cat-inflicted bite wound is given prophylactic/empiric penicillin or a derivative to prevent Pasteurella infection (provided they are not allergic to penicillins). In an effort to establish a carriage rate of P. multocida in the domestic feline, bacterial samples from the gingival margins of domestic northern Ohio cats (n=409) were cultured. Isolates were tested for antibiotic sensitivity as prophylactic/empiric use of penicillin and its derivatives could potentially give rise to antibiotic resistance in P. multocida. The high carriage rate (approximately 90%) of P. multocida observed was found to be independent of physiological and behavioural variables including age, breed, food type, gingival scale, lifestyle and sex. High antibiotic susceptibility percentages were observed for benzylpenicillin, amoxicillin-clavulanate, cefazolin, and azithromycin (100%, 100%, 98.37% and 94.02%, respectively) in P. multocida isolates. The high prevalence of P. multocida in the feline oral cavity indicates that prophylactic/empiric antibiotic therapy is still an appropriate response to cat bite wounds. Additionally, the susceptibility of P. multocida to penicillin and its derivatives indicates that they remain reliable choices for preventing and treating P. multocida infections.

Multiorgan Failure and Refractory Lactic Acidosis due to Pasteurella multocida Septicemia in a Patient with No Animal Exposure

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Damaris Pena

2018-01-01

Full Text Available Introduction. Pasteurella multocida is a gram-negative coccobacillus pathogenic to animals. It can cause infection in humans by a bite, scratch, or lick from a cat or dog. P. multocida can cause a variety of infections in humans, including cellulitis, osteomyelitis, endocarditis, peritonitis, and septic shock. Case Presentation. A 56-year-old male presented to our hospital with a 2-day history of fever, abdominal pain, nausea, and vomiting. He denied exposure to cats, dogs or other pets. He had severe respiratory distress requiring ventilator support, profound septic shock requiring multiple vasopressors, severe lactic acidosis, and renal failure requiring emergent hemodialysis. Blood cultures confirmed the presence of P. multocida. The patient subsequently died of cardiopulmonary arrest due to multiorgan failure with refractory shock. Conclusion. P. multocida septicemia can lead to septic shock. Early identification of this organism may decrease mortality. Although our patient had no known cat or dog exposure, physicians should enquire about a history of animal exposure when a patient presents with an infection with no obvious cause.

Genotyping of Pasteurella multocida ovine and bovine isolates from Iran based on PCR-RFLP of ompH gene

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A. Ghanizadeh

2015-10-01

Full Text Available Pasteurella multocida (P. multocida, A Gram-negative facultative anaerobic bacterium, is a causative animal pathogen in porcine atrophic rhinitis and avian fowl cholera. The outer membrane of Gram-negative bacteria contains of many different protein in very high copy numbers. One of the major outer membrane, the H proteins have functional as high immunogenicity and antigenicity. In this study to increase information about epidemiology of ovine and bovine P. multocida, the 24 isolates from sheep and nine isolates from cattle were investigated by PCR-RFLP analysis of the ompH gene. In all 33 isolates, digestion of the amplified fragment of ompH gene by using EcoRI, cfoI and HindIII produced 3, 5 and 3 different restriction patterns respectively. Sixteen RFLP patterns were found among 33 investigated P.multocida isolates. This study showed that, the PCR RFLP based on ompH gene is potentially a useful method for typing of P. multocida isolates from sheep and cattle. The RFLP patterns of this gene exhibited extensive restriction site heterogeneity, which may be particularly suitable for fingerprinting of P. multocida isolates.Considering ompH protein as a protective immunogenic moiety of P.ultocida, the results of this study showed a heterogenic bacteria and this means the possibility to produce a multivalent vaccine to be protective against diseases caused by this organism in sheep and cattle in Iran.

Time-course investigation of infection with a low virulent Pasteurella multocida strain in normal and immune-suppressed 12-week-old free-range chickens

DEFF Research Database (Denmark)

Mbuthia, P.G.; Njagi, L.W.; Nyaga, P.N.

2011-01-01

Twelve-week-old indigenous chickens, either immune-suppressed using dexamethasone (IS) or non-immune-suppressed (NIS), were challenged with a low virulent strain, Pasteurella multocida strain NCTC 10322(T), and developed clinical signs and pathological lesions typical of chronic fowl cholera. NIS...

Structure and function of C-terminal catalytic region of pasteurella multocida toxin

International Nuclear Information System (INIS)

Kitadokoro, Kengo; Kamitami, Shigeki; Horiguchi, Yasuhiko

2008-01-01

Pasteurella multocida toxin (PMT) is one of virulence factors responsible for the pathogenesis in some Pasteurellosis. We determined the crystal structure of the C-terminal region of PMT (C-PMT), which carries an intracellularly active moiety. The overall structure of C-PMT displays three different domains designated C1, C2 and C3. We found in the C3 domain the Cys-His-Asp catalytic triad that is organized only when the Cys is released from a disulfide bond. The steric alignment of the triad corresponded well to that of papain or other enzymes carrying the Cys-His-Asp triad. Our results demonstrate that PMT is an enzymatic toxin carrying the cysteine-protease like catalytic triad, which is organized only under reducing conditions. (author)

Prosthetic joint infection caused by Pasteurella multocida: a case series and review of literature.

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Honnorat, Estelle; Seng, Piseth; Savini, Hélène; Pinelli, Pierre-Olivier; Simon, Fabrice; Stein, Andreas

2016-08-20

Pasteurella multocida is a well-recognized zoonotic agent following dog or cat bites or scratches. Nevertheless, prosthetic joint infection caused by P. multocida are rarely reported. We report here a series of six cases of prosthetic joint infection caused by P. multocida managed at a referral centre for the treatment of bone and joint infection in southern France. We also reviewed the 26 cases reported in literature. The mean age of our cases was 74 years [±8.2, range 63-85]. In majority of our cases (5 cases) were associated with knee prostheses and one case with a hip prosthesis. Most of cases occurred after cat or dog scratches or licks or contact. Diagnoses of prosthetic joint infection caused by P. multocida were made by positive cultures of surgical biopsies or needle aspiration. Mean time delay between prosthetic joint implantation and infection onset was 7.6 years (±5.12 years, range 2-17). Local inflammation, which occurred in all six cases, was the most frequent clinical symptom, followed by pain in five cases, fever and swollen joints in four cases, and a fistula with purulent discharge inside the wound in two cases. The mean time of antibiotic therapy was 8 months. Surgical treatment with prosthesis removal was performed in three cases. Six of our cases were in remission without apparent relapse at 3 years after end of treatment. Prosthetic joint infections caused by P. multocida usually occur after animal scratches or bites, but can occasionally occur after a short animal lick. These infections are usually resulting from a contiguous infection and localized in the knee. An early antibiotic therapy after surgical debridement could avoid prosthetic withdrawal, notably in elderly patients. Patients with prosthetic joints should be warned that animals are potential sources of serious infection and urgent medical advice should be sought if they are bitten or scratched.

Analysis of the polymerization initiation and activity of Pasteurella multocida heparosan synthase PmHS2, an enzyme with glycosyltransferase and UDP-sugar hydrolase activity

NARCIS (Netherlands)

Chavaroche, A.A.E.; Broek, van den L.A.M.; Springer, J.; Boeriu, C.; Eggink, G.

2011-01-01

Heparosan synthase catalyzes the polymerization of heparosan [-4GlcUAß1-4GlcNAca1-]n by transferring alternatively the monosaccharide units from UDP-GlcUA and UDP-GlcNAc to an acceptor molecule. Details on the heparosan chain initiation by Pasteurella multocida heparosan synthase PmHS2 and its

Establishment of a Pathogenicity Index for One-day-old Broilers to Pasteurella multocida Strains Isolated from Clinical Cases in Poultry and Swine

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RM Pilatti

Full Text Available ABSTRACT Although Pasteurella multocida is a member of the respiratory microbiota, under some circumstances, it is a primary agent of diseases , such as fowl cholera (FC, that cause significant economic losses. Experimental inoculations can be employed to evaluate the pathogenicity of strains, but the results are usually subjective and knowledge on the pathogenesis of this agent is still limited. The objective of this study was to establish a new methodology for classifying the pathogenicity of P. multocida by formulating a standard index. Strains isolated from FC cases and from swine with respiratory problems were selected. One hundred mL of a bacterial culture of each strain, containing 106 CFU, was inoculated in 10 one-day-old broilers. Mortality after inoculation, time of death (TD, and the presence of six macroscopic lesions were evaluated over a period of seven days post-inoculation (dpi. A Pathogenicity Index Per Bird (IPI, ranging 0 to 10, was calculated. Liver and heart fragments were collected to reisolate the bacteria. Blood was collected from the surviving birds, and an ELISA test was carried out to detect specific antibodies. The median of the pathogenicity indices, the number of lesions and the rate of bacteria reisolation were significantly different (p<0.05 among the origins of the isolates (p<0.05. The pathogenicity index developed in this study allows the classification of Pasteurella multocida pathogenicity and may be an alternative to the pathogenicity models currently used for screening.

Pharmacokinetic/pharmacodynamic integration and modelling of oxytetracycline for the porcine pneumonia pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida.

Science.gov (United States)

Dorey, L; Pelligand, L; Cheng, Z; Lees, P

2017-10-01

Pharmacokinetic-pharmacodynamic (PK/PD) integration and modelling were used to predict dosage schedules of oxytetracycline for two pig pneumonia pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida. Minimum inhibitory concentration (MIC) and mutant prevention concentration (MPC) were determined in broth and porcine serum. PK/PD integration established ratios of average concentration over 48 h (C av0-48 h )/MIC of 5.87 and 0.27 μg/mL (P. multocida) and 0.70 and 0.85 μg/mL (A. pleuropneumoniae) for broth and serum MICs, respectively. PK/PD modelling of in vitro time-kill curves established broth and serum breakpoint values for area under curve (AUC 0-24 h )/MIC for three levels of inhibition of growth, bacteriostasis and 3 and 4 log 10 reductions in bacterial count. Doses were then predicted for each pathogen, based on Monte Carlo simulations, for: (i) bacteriostatic and bactericidal levels of kill; (ii) 50% and 90% target attainment rates (TAR); and (iii) single dosing and daily dosing at steady-state. For 90% TAR, predicted daily doses at steady-state for bactericidal actions were 1123 mg/kg (P. multocida) and 43 mg/kg (A. pleuropneumoniae) based on serum MICs. Lower TARs were predicted from broth MIC data; corresponding dose estimates were 95 mg/kg (P. multocida) and 34 mg/kg (A. pleuropneumoniae). © 2017 The Authors. Journal of Veterinary Pharmacology and Therapeutics Published by John Wiley & Sons Ltd.

Susceptibilidade in vitro a antimicrobianos da Mannheimia haemolytica e da Pasteurella multocida isoladas de ovinos sadios e com doenças respiratórias

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Leomar Viana

2007-12-01

Full Text Available Pasteurella multocida e Mannheimia haemolytica (P. haemolytica estão associadas a enfermidades no sistema respiratório de ovinos. Com o objetivo de avaliar a susceptibilidade in vitro destes microrganismos frente aos antimicrobianos, foram colhidas amostras de nasofaringe (n=180 e orofaringe (n=82 de ovinos com e sem enfermidade respiratória. Dentre os antimicrobianos testados, a sensibilidade foi maior para enrofloxacina (100% e florfenicol (100%, considerando-se ambas as espécies bacterianas. Observou-se resistência de M. haemolytica e P. multocida à tetraciclina (15,64% e 17,65%, respectivamente e penicilina (1.82% e 4.2%, respectivamente.

What is the true in vitro potency of oxytetracycline for the pig pneumonia pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida?

Science.gov (United States)

Dorey, L; Hobson, S; Lees, P

2017-10-01

The pharmacodynamics of oxytetracycline was determined for pig respiratory tract pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida. Indices of potency were determined for the following: (i) two matrices, broth and pig serum; (ii) five overlapping sets of twofold dilutions; and (iii) a high strength starting culture. For A. pleuropneumoniae, minimum inhibitory concentration (MIC) was similar for the two matrices, but for P. multocida, differences were marked and significantly different. MIC and minimum bactericidal concentration (MBC) serum: broth ratios for A. pleuropneumoniae were 0.83:1 and 1.22:1, respectively, and corresponding values for P. multocida were 22.0:1 and 7.34:1. For mutant prevention concentration (MPC) serum: broth ratios were 0.79:1 (A. pleuropneumoniae) and 20.9:1 (P. multocida). These ratios were corrected for serum protein binding to yield fraction unbound (fu) serum: broth MIC ratios of 0.24:1 (A. pleuropneumoniae) and 6.30:1 (P. multocida). Corresponding fu serum: broth ratios for MPC were almost identical, 0.23:1 and 6.08:1. These corrections for protein binding did not account for potency differences between serum and broth for either species; based on fu serum MICs, potency in serum was approximately fourfold greater than predicted for A. pleuropneumoniae and sixfold smaller than predicted for P. multocida. For both broth and serum and both bacterial species, MICs were also dependent on initial inoculum strength. The killing action of oxytetracycline had the characteristics of codependency for both A. pleuropneumoniae and P. multocida in both growth media. The in vitro potency of oxytetracycline in pig serum is likely to be closer to the in vivo plasma/serum concentration required for efficacy than potency estimated in broths. © 2017 The Authors. Journal of Veterinary Pharmacology and Therapeutics Published by John Wiley & Sons Ltd.

Oral exposure to culture material extract containing fumonisins predisposes swine to the development of pneumonitis caused by Pasteurella multocida

International Nuclear Information System (INIS)

Halloy, David J.; Gustin, Pascal G.; Bouhet, Sandrine; Oswald, Isabelle P.

2005-01-01

Fumonisin B 1 (FB 1 ) is a mycotoxin produced by Fusarium verticillioides and F. proliferatum that commonly occurs in maize. In swine, consumption of contaminated feed induces liver damage and pulmonary edema. Pasteurella multocida is a secondary pathogen, which can generate a respiratory disorder in predisposed pigs. In this study, we examined the effect of oral exposure to fumonisin-containing culture material on lung inflammation caused by P. multocida. Piglets received by gavage a crude extract of fumonisin, 0.5 mg FB 1 /kg body weight/day, for 7 days. One day later, the animals were instilled intratracheally with a non toxin producing type A strain of P. multocida and followed up for 13 additional days. Pig weight and cough frequency were measured throughout the experiment. Lung lesions, bronchoalveolar lavage fluid (BALF) cell composition and the expression of inflammatory cytokines were evaluated at the autopsy. Ingestion of fumonisin culture material or infection with P. multocida did not affect weight gain, induced no clinical sign or lung lesion, and only had minimal effect on BALF cell composition. Ingestion of mycotoxin extract increased the expression of IL-8, IL-18 and IFN-γ mRNA compared with P. multocida infection that increased the expression of TNF-α. The combined treatment with fumonisin culture material and P. multocida delayed growth, induced cough, and increased BALF total cells, macrophages and lymphocytes. Lung lesions were significantly enhanced in these animals and consisted of subacute interstitial pneumonia. TNF-α, IFN-γ and IL-18 mRNA expression was also increased. Taken together, our data showed that fumonisin culture material is a predisposing factor to lung inflammation. These results may have implications for humans and animals consuming FB 1 contaminated food or feed

Oral exposure to culture material extract containing fumonisins predisposes swine to the development of pneumonitis caused by Pasteurella multocida

Energy Technology Data Exchange (ETDEWEB)

Halloy, David J [Department of Functional Sciences, Unit of Pharmacology, Pharmacotherapy and Toxicology, Faculty of Veterinary Medicine, University of Liege, Liege (Belgium); Gustin, Pascal G [Department of Functional Sciences, Unit of Pharmacology, Pharmacotherapy and Toxicology, Faculty of Veterinary Medicine, University of Liege, Liege (Belgium); Bouhet, Sandrine [INRA, UR66, Laboratory of Pharmacology and Toxicology, 180 Chemin de Tournefeuille, BP3, 31931 Toulouse (France); Oswald, Isabelle P [INRA, UR66, Laboratory of Pharmacology and Toxicology, 180 Chemin de Tournefeuille, BP3, 31931 Toulouse (France)

2005-09-15

Fumonisin B{sub 1} (FB{sub 1}) is a mycotoxin produced by Fusarium verticillioides and F. proliferatum that commonly occurs in maize. In swine, consumption of contaminated feed induces liver damage and pulmonary edema. Pasteurella multocida is a secondary pathogen, which can generate a respiratory disorder in predisposed pigs. In this study, we examined the effect of oral exposure to fumonisin-containing culture material on lung inflammation caused by P. multocida. Piglets received by gavage a crude extract of fumonisin, 0.5 mg FB{sub 1}/kg body weight/day, for 7 days. One day later, the animals were instilled intratracheally with a non toxin producing type A strain of P. multocida and followed up for 13 additional days. Pig weight and cough frequency were measured throughout the experiment. Lung lesions, bronchoalveolar lavage fluid (BALF) cell composition and the expression of inflammatory cytokines were evaluated at the autopsy. Ingestion of fumonisin culture material or infection with P. multocida did not affect weight gain, induced no clinical sign or lung lesion, and only had minimal effect on BALF cell composition. Ingestion of mycotoxin extract increased the expression of IL-8, IL-18 and IFN-{gamma} mRNA compared with P. multocida infection that increased the expression of TNF-{alpha}. The combined treatment with fumonisin culture material and P. multocida delayed growth, induced cough, and increased BALF total cells, macrophages and lymphocytes. Lung lesions were significantly enhanced in these animals and consisted of subacute interstitial pneumonia. TNF-{alpha}, IFN-{gamma} and IL-18 mRNA expression was also increased. Taken together, our data showed that fumonisin culture material is a predisposing factor to lung inflammation. These results may have implications for humans and animals consuming FB{sub 1} contaminated food or feed.

Mucoadhesive and pH-sensitive thiolated Eudragit microspheres for oral delivery of Pasteurella multocida antigens containing dermonecrotoxin.

Science.gov (United States)

Islam, Mohammad Ariful; Jiang, Hu-Lin; Quan, Ji-Shan; Arote, Rohidas B; Kang, Mi-Lan; Yoo, Han-Sang; Yun, Cheol-Heui; Choi, Yun-Jaie; Cho, Chong-Su

2011-05-01

In this study, cysteine was conjugated to the Eudragit to have mucoadhesive and pH-sensitive properties. Pasteurella multocida dermonecrotoxin (PMT) is a major virulence factor as a causative agent of atrophic rhinitis (AR) in swine and, therefore, inactivated P. multocida was used as a candidate vaccine in the current study. PMT-loaded thiolated Eudragit microspheres (TEMS) prepared using W/O/W emulsion-solvent evaporation method were characterized to assess their efficacy in oral vaccination. PMT-loaded TEMS were observed as spherical shapes with smooth surfaces and average particle sizes were 5.2 +/- 0.55 microm. The loading efficiency of PMT in the TEMS was about 75.3%. A significantly higher percentage of PMT from PMT-loaded TEMS was released at pH 7.4 than at pH 1.5. Murine macrophage stimulated with PMT-loaded TEMS facilitated a gradual secretion of tumor necrosis factor-alpha and nitric oxide as immune stimulatory mediators in a time dependent manner, suggesting that the released PMT from PMT-loaded TEMS had immune stimulating activity of AR vaccine in vitro.

Modulating the regioselectivity of a Pasteurella multocida sialyltransferase for biocatalytic production of 3'- and 6'-sialyllactose

DEFF Research Database (Denmark)

Guo, Yao; Jers, Carsten; Meyer, Anne S.

2015-01-01

Several bacterial sialyltransferases have been reported to be multifunctional also catalysing sialidase and trans-sialidase reactions. In this study, we examined the trans-sialylation efficacy and regioselectivity of mutants of the multifunctional Pasteurella multocida sialyltransferase (Pm...... activity was abolished. Histidine in this position is conserved in α-2,6-sialyltransferases and has been suggested, and recently confirmed, to be the determinant for strict regiospecificity in the sialyltransferase reaction. Our data verified this theorem. In trans-sialidase reactions, the P34H mutant...... displayed a distinct preference for 6'-sialyllactose synthesis but low levels of 3'-sialyllactose were also produced. The sialyllactose yield was however lower than when using PmSTWT under optimal conditions for 6'-sialyllactose formation. The discrepancy in regiospecificity between the two reactions could...

Occurrence Of Virulence Factors And Antimicrobial Resistance In Pasteurella Multocida Strains Isolated From Slaughter Cattle In Iran

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Faham eKhamesipour

2014-10-01

Full Text Available A total of 30 Pasteurella multocida strains isolated from 333 pneumonic and apparently health slaughter cattle were examined for capsule biosynthesis genes and 23 virulence associated genes by polymerase chain reaction. The disc diffusion technique was used to determine antimicrobial resistance profiles among the isolates. Of the isolates, 23 belonged to capsular type A, 5 to capsular type D and two isolates were untypeable. The distribution of the capsular types in pneumonic lungs and in apparently health lungs was statistically similar. All virulence genes tested were detected among the isolates derived from pneumonic lungs; whereas isolates derived from apparently health lungs carried 16 of the 23 genes. The frequently detected genes among isolates from pneumonic lungs were exbD, hgbA, hgbB, ompA, ompH, oma87 and sodC; whereas tadD, toxA and pmHAS genes occurred less frequently. Most of the adhesins and superoxide dismutases; and all of the iron acquisition and protectin proteins occurred at significantly (p≤0.05 higher frequencies in isolates from pneumonic lungs. Isolates from apparently healthy lungs didn’t carry the following genes; hsf-1, hsf-2, tadD, toxA, nanB, nanH and pmHAS. One adhesion (hsf-1 and two iron acquisition (exbD and tonB genes occurred at significantly (p≤0.05 higher frequencies among capA isolates. All the P. multocida isolates were susceptible to ciprofloxacin, co-trimoxazole, doxycycline, enrofloxacin, nitrofurantoin and tetracyclines. Different proportions of the isolates were however resistant to ampicillin, amoxicillin, erythromycin, lincomycin, penicillin, rifampin, streptomycin and florfenicol. Our results reveal presence of virulence factors in P. multocida strains isolated from symptomatic and asymptomatic bovids. A higher frequency of the factors among isolates from symptomatic study animals may suggest their role in pathogenesis of P. multocida-associated bovine respiratory disease. The results further

Isolation, identification, and monitoring of antibiotic resistance in Pasteurella multocida and Mannheimia haemolytica isolated from sheep in East Azerbaijan province, Iran

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I. Khalili

2016-09-01

Full Text Available The present study was carried out in order to isolate, identify, and assess the antimicrobial susceptibility of the causative agent(s of pneumonic pasteurellosis in sheep in East Azerbaijan province, northwest of Iran. Pneumonia was detected in 320 cases, and the affected lungs were sampled in the slaughterhouse. The samples were investigated bacteriologically for the isolation of two microorganisms from the Pasteurellaceae family. Pasteurella multocida was isolated from six (1.87% samples, while none of the lung tissues were positive for Mannheimia haemolytica. After the isolation and detection of microorganisms via cultural and morphological tests, the bacteria were identified on the basis of biochemical criteria and polymerase chain reaction (PCR technique. Antimicrobial susceptibility testing was performed on all P. multocida isolates, using broth microdilution method. Evaluation of the minimum inhibitory concentration (MIC of eight antimicrobial agents against the tested isolates showed that all the organisms were resistant to amoxicillin and relatively susceptible to ceftiofur. In conclusion, P. multocida was introduced as the main cause of ovine pneumonic pasteurellosis in the studied district, and the outbreak frequency significantly varied in different seasons of the year (P

Ocorrência de genes tad associados à formação de biofilme em isolados de Pasteurella multocida de pulmões de suínos com pneumonia

OpenAIRE

Moraes, Danny Franciele da S.D.; Brandão, Laila Natasha S.; Pitchenin, Leticia C.; O. Filho, João Xavier; Morés, Nelson; Nakazato, Luciano; Dutra, Valéria

2014-01-01

Os atuais sistemas de criação intensiva de suínos aumentam a pressão de seleção microbiana propiciando a disseminação de doenças respiratórias. A bactéria Pasteurella multocida é associada a diversas patologias respiratórias em animais submetidos a esse tipo de criação, causando grandes perdas econômicas. A formação de biofilme foi descrita in vitro em P. multocida e fatores analisados indicaram a facilitação na colonização dos tecidos, aumentando a resistência às defesas do hospedeiro e aos ...

Isolation and molecular detection of Pasteurella multocida Type A from naturally infected chickens, and their histopathological evaluation in artificially infected chickens in Bangladesh

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Sayedun Nahar Panna

2015-09-01

Full Text Available Pasteurella multocida type A is the etiologic agent of fowl cholera, a highly contagious and fatal disease of chickens. The present research work was performed for the isolation, identification and molecular detection of P. multocida Type A from chickens. Liver, heart and spleen of suspected dead chicken (n=35 were collected from Gazipur and Pabna districts in Bangladesh. The targeted bacteria from the samples were isolated, identified and characterized based on their morphology, staining, cultural, biochemical characters, pathogenicity test, histopathological study and Polymerase Chain Reaction (PCR. The P. multocida organism was isolated from 11.42% (n=4/35 samples. The organisms were gram negative, non-spore forming rod, non-motile, occurring singly or pairs in Gram staining, whereas in Leishman's stain, bipolar shaped organisms were observed. All the isolates were found positive for oxidase and catalase tests, produced indole, and fermented glucose, mannitol and sucrose. Necrotic foci in liver and congestion with hemorrhages in heart were found on necropsy. After pathogenicity test, the pathological changes were reconfirmed by histopathology depicting congestion, hemorrhage and lymphocyte infiltration in heart, liver and spleen tissues. In type specific PCR reaction, the organisms were confirmed as P. multocida Type A. In conclusion, P. multocida type A is prevalent among poultry in the studied regions; thus, care must be taken to control of the disease. [J Adv Vet Anim Res 2015; 2(3.000: 338-345

[Effect of lead microparticles introduced into the respiratory system of the sensitivity of mice to Pasteurella multocida infection via aerosol].

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Bouley, G; Dubreuil, A; Arsac, F; Boudène, C

1977-12-19

Lead microparticles, resulting from the pyrolysis of organic lead used as an anti-knock agent in gasoline, were introduced into the lungs of Mice, during a short single exposure. When 6 microgram of lead were retained in the lungs (mean value per Mouse), the phagocytic ability of the pulmonary alveolar macrophages harvested 6 and 18 hrs. later, was significantly reduced. It was observed, in the same conditions, that the resistance of Mice to experimental infection by aerosolized Pasteurella multocida, was significantly reduced. When 3 microgram of lead were retained in the lungs, there was no significant difference between control and intoxicated Mice.

Bronchoalveolar lavage is an ideal tool in evaluation of local immune response of pigs vaccinated with Pasteurella multocida bacterin vaccine

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Shiney George

2015-04-01

Full Text Available Aim: The aim was to study the bronchoalveolar lavage (BAL technique in evaluating the local immune response of pig immunized with Pasteurella multocida bacterin vaccine. Materials and Methods: Weaned piglets were immunized with formalin-inactivated P52 strain of P. multocida bacterin and evaluated for pulmonary immune response in BAL fluid. BAL was performed before vaccination and at different post vaccination days. The BAL fluid was assayed using enzyme-linked immunosorbent assay to study the development of P. multocida specific antibody isotypes and also evaluated for different cell populations using standard protocol. Results: The average recovery percentage of BAL fluid varies from 58.33 to 61.33 in vaccinated and control group of piglets. The BAL fluid of vaccinated pigs showed increase in antibody titer up to 60th days post vaccination (8.98±0.33, IgG being the predominant isotype reached maximum titer of 6.12±0.20 on 45th days post vaccination, followed by IgM and a meager concentration of IgA could be detected. An increased concentration of the lymphocyte population and induction of plasma cells was detected in the BAL fluid of vaccinated pigs. Conclusion: Though intranasal vaccination with P. multocida plain bacterin vaccine could not provoke a strong immune response, but is promising as lymphocyte population was increased and plasma cells were detected. BAL can be performed repeatedly up to 3/4 months of age in pigs to study pulmonary immune response without affecting their health.

Ultrastructural Comparison of the Nasal Epithelia of Healthy and Naturally Affected Rabbits with Pasteurella multocida A

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Paula Esquinas

2013-01-01

Full Text Available An ultrastructural comparison between the nasal cavities of healthy rabbits and those suffering from two forms of spontaneous infection with Pasteurella multocida was undertaken. Twelve commercially produced rabbits of different ages and respiratory health status were divided into four groups: healthy from 0 to 21 days (G1, n=2; healthy from 23 to 49 days (G2, n=2; healthy from 51 to 69 days (G3, n=2; diseased rabbits with septicemia and the rhinitic form of P. multocida infection (G4, n=3. The main ultrastructural changes observed were a widening of the interepithelial spaces, increased activity and number of goblet cells, the formation of two types of vacuoles in epithelial cells, the degranulation and migration of heterophils between the epithelial cells, and the association of this migration with some of the other changes. No bacteria were observed adhering to the epithelium, and very few were observed free in the mucus. Scant inter-epithelial spaces were found in healthy rabbits, but they were not as large and numerous as those found in diseased animals. We discuss the origin and meaning of these changes but, we focus on the significance of the inter-epithelial spaces and goblet cells for the defense of the upper respiratory airways against the bacterium and its lipopolysaccharide.

Efeito do extrato alcoólico de própolis sobre a Pasteurella multocida “in vitro” e em coelhos - DOI: 10.4025/actascianimsci.v26i1.1952 Effect of alcohol extract of propolis on the Pasteurella multocida in vitro and in the rabbits - DOI: 10.4025/actascianimsci.v26i1.1952

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Hélio Langoni

2004-04-01

Full Text Available O ensaio in vitro objetivou avaliar o efeito do álcool PA e de diferentes concentrações (5%, 10% e 15% no Agar, do Extrato Alcoólico de Própolis (EAP, de três regiões do Estado de São Paulo, sobre a Pasteurella multocida, obtida a partir de swab nasal de coelhos. Por meio de outro ensaio, analisou-se o comportamento dessas bactérias em lavado tráqueo-brônquico de coelhos, alimentados com rações contendo álcool PA e diferentes concentrações de EAP (0,1%; 0,2% e 0,3%. O álcool só foi efetivo na inibição do desenvolvimento bacteriano in vitro na concentração mais elevada, enquanto o EAP demonstrou efetividade em todas as concentrações. As amostras de própolis das três regiões não diferiram entre si. No lavado tráqueo-brônquico, o número de Unidades Formadoras de Colônias por mililitro não diferiu entre os tratamentos, porém houve uma tendência de maior efetividade nos tratamentos com EAP em relação ao álcool, acompanhando a ação in vitro.The essay in vitro aimed to evaluate the effect of alcohol and different concentrations (5, 10 and 15% in the agar, of Alcoholic Extract of Propolis (AEP, from three regions of São Paulo State, Brazil, on Pasteurella multocida, obtained from rabbits’ nasal swabs. In other essay the reaction of this bacteria was observed. In tracheal regions of rabbits, fed on diets with alcohol and AEP in different concentrations (0.1; 0.2 and 0.3%. The alcohol was only effective on the inhibition of the bacteria in vitro on highest concentration, while the AEP was effective in all concentrations. The propolis samples from three regions did not differ. In the other assay, there wasn’t any difference between treatments, but the AEP showed to be more active than alcohol against Pasteurella multocida, in the tracheal region of the rabbits, as to the action in vitro.

Field study of pneumonia in vaccinated cattle associated with incorrect vaccination and Pasteurella multocida infection.

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Crawshaw, W M; Caldow, G L

2015-04-25

This field study used data on the vaccine courses against bovine respiratory disease sold by one pharmaceutical company in conjunction with pharmacovigilance data to explore reported suspected lack of expected efficacy and the reasons for this. The study ran from May 1, 2007, to April 30, 2010, and covered vaccines sold in Scotland and part of Northumberland. In total, 83 groups of cattle reported suspected lack of expected efficacy, representing 1.6 per cent of the 804,618 vaccine courses sold. It was possible to investigate 45 of these outbreaks in depth using a standard questionnaire and diagnostic protocol. Vaccine usage outwith the specific product characteristics (SPC) occurred in 47 per cent of cases (21/45). The proportion of vaccination courses used where a pathogen contained in the vaccine was detected in the diseased cattle and vaccine use was consistent with the SPC was estimated at 0.12 per cent of the courses sold. Pasteurella multocida was the most common pathogen detected and was found in 21 of the outbreaks. For outbreaks where a pathogen contained in the vaccine was detected, P. multocida was found at a significantly greater frequency (P=0.03) where vaccine use was compliant with the SPC (five of six outbreaks) compared with outbreaks where vaccine use had not been compliant with the SPC (one of seven outbreaks). The limitations of the study, including the diagnostic tests employed and definition of vaccination outwith the SPC, are discussed. British Veterinary Association.

Pharmacokinetic/pharmacodynamic integration and modelling of florfenicol for the pig pneumonia pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida.

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Lucy Dorey

Full Text Available Pharmacokinetic-pharmacodynamic (PK/PD integration and modelling were used to predict dosage schedules for florfenicol for two pig pneumonia pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida. Pharmacokinetic data were pooled for two bioequivalent products, pioneer and generic formulations, administered intramuscularly to pigs at a dose rate of 15 mg/kg. Antibacterial potency was determined in vitro as minimum inhibitory concentration (MIC and Mutant Prevention Concentration in broth and pig serum, for six isolates of each organism. For both organisms and for both serum and broth MICs, average concentration:MIC ratios over 48 h were similar and exceeded 2.5:1 and times greater than MIC exceeded 35 h. From in vitro time-kill curves, PK/PD modelling established serum breakpoint values for the index AUC24h/MIC for three levels of inhibition of growth, bacteriostasis and 3 and 4log10 reductions in bacterial count; means were 25.7, 40.2 and 47.0 h, respectively, for P. multocida and 24.6, 43.8 and 58.6 h for A. pleuropneumoniae. Using these PK and PD data, together with literature MIC distributions, doses for each pathogen were predicted for: (1 bacteriostatic and bactericidal levels of kill; (2 for 50 and 90% target attainment rates (TAR; and (3 for single dosing and daily dosing at steady state. Monte Carlo simulations for 90% TAR predicted single doses to achieve bacteriostatic and bactericidal actions over 48 h of 14.4 and 22.2 mg/kg (P. multocida and 44.7 and 86.6 mg/kg (A. pleuropneumoniae. For daily doses at steady state, and 90% TAR bacteriostatic and bactericidal actions, dosages of 6.2 and 9.6 mg/kg (P. multocida and 18.2 and 35.2 mg/kg (A. pleuropneumoniae were required. PK/PD integration and modelling approaches to dose determination indicate the possibility of tailoring dose to a range of end-points.

Investigation of genetic diversity and epidemiological characteristics of Pasteurella multocida isolates from poultry in southwest China by population structure, multi-locus sequence typing and virulence-associated gene profile analysis.

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Li, Zhangcheng; Cheng, Fangjun; Lan, Shimei; Guo, Jianhua; Liu, Wei; Li, Xiaoyan; Luo, Zeli; Zhang, Manli; Wu, Juan; Shi, Yang

2018-04-25

Fowl cholera caused by Pasteurella multocida has always been a disease of global importance for poultry production. The aim of this study was to obtain more information about the epidemiology of avian P. multocida infection in southwest China and the genetic characteristics of clinical isolates. P. multocida isolates were characterized by biochemical and molecular-biological methods. The distributions of the capsular serogroups, the phenotypic antimicrobial resistance profiles, lipopolysaccharide (LPS) genotyping and the presence of 19 virulence genes were investigated in 45 isolates of P. multocida that were associated with clinical disease in poultry. The genetic diversity of P. multocida strains was performed by 16S rRNA and rpoB gene sequence analysis as well as multilocus sequence typing (MLST). The results showed that most (80.0%) of the P. multocida isolates in this study represented special P. multocida subspecies, and 71.1% of the isolates showed multiple-drug resistance. 45 isolates belonged to capsular types: A (100%) and two LPS genotypes: L1 (95.6%) and L3 (4.4%). MLST revealed two new alleles (pmi77 and gdh57) and one new sequence type (ST342). ST129 types dominated in 45 P. multocida isolates. Isolates belonging to ST129 were with the genes ompH+plpB+ptfA+tonB, whereas ST342 included isolates with fur+hgbA+tonB genes. Population genetic analysis and the MLST results revealed that at least one new ST genotype was present in the avian P. multocida in China. These findings provide novel insights into the epidemiological characteristics of avian P. multocida isolates in southwest China.

Serological patterns of Actinobacillus pleuropneumoniae, Mycoplasma hyopneumoniae, Pasteurella multocida and Streptococcus suis in pig herds affected by pleuritis.

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Wallgren, Per; Nörregård, Erik; Molander, Benedicta; Persson, Maria; Ehlorsson, Carl-Johan

2016-10-04

Respiratory illness is traditionally regarded as the disease of the growing pig, and has historically mainly been associated to bacterial infections with focus on Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae. These bacteria still are of great importance, but continuously increasing herd sizes have complicated the scenario and the influence of secondary invaders may have been increased. The aim of this study was to evaluate the presence of A. pleuropneumoniae and M. hyopneumoniae, as well as that of the secondary invaders Pasteurella multocida and Streptococcus suis by serology in four pig herds (A-D) using age segregated rearing systems with high incidences of pleuritic lesions at slaughter. Pleuritic lesions registered at slaughter ranged from 20.5 to 33.1 % in the four herds. In herd A, the levels of serum antibodies to A. pleuropneumoniae exceeded A 450  > 1.5, but not to any other microbe searched for. The seroconversion took place early during the fattening period. Similar levels of serum antibodies to A. pleuropneumoniae were also recorded in herd B, with a subsequent increase in levels of antibodies to P. multocida. Pigs seroconverted to both agents during the early phase of the fattening period. In herd C, pigs seroconverted to P. multocida during the early phase of the fattening period and thereafter to A. pleuropneumoniae. In herd D, the levels of antibodies to P. multocida exceeded A 450  > 1.0 in absence (A 450  hyopneumoniae and to S. suis remained below A 450  hyopneumoniae late during the rearing period (herd B-D), or not at all (herd A). Different serological patterns were found in the four herds with high levels of serum antibodies to A. pleuropneumoniae and P. multocida, either alone or in combination with each other. Seroconversion to M. hyopneumoniae late during the rearing period or not at all, confirmed the positive effect of age segregated rearing in preventing or delaying infections with M

Rapid diagnosis of virulent Pasteurella multocida isolated from farm animals with clinical manifestation of pneumonia respiratory infection using 16S rDNA and KMT1 gene

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Gamal Mohamedin Hassan

2016-01-01

Full Text Available Objective: To characterize intra-isolates variation between clinical isolates of Pasteurella multocida (P. multocida isolated from sheep, cattle and buffalo at molecular level to check the distribution of pneumonia and hemorrhagic septicemia in some regions of Fayoum, Egypt. Methods: These isolates were obtained from various locations in the Fayoum Governorate, Egypt and they were identified by amplifying 16S rDNA and KMT1 genes using their DNA as a template in PCR reaction. Results: The results demonstrated that the five selective isolates of P. multocida had similar size of PCR products that generated one band of 16S rDNA having 1 471 bp and KMT1 gene having 460 bp. The phylogenetic tree and similarity of the five selective isolates of P. multocida which were collected from GenBank database were calculated and analyzed for the nucleotide sequence of 16S rDNA and KMT1 genes. The sequencing result of 16S rRNA gene product (1 471 bp for the five selective isolates of P. multocida showed that the isolates of sheep (FUP2 shared 94.08%, 88.10% homology with the buffalo isolate (FUP8 and cattle isolate (FUP9 respectively, whereas, the buffalo isolate (FUP5 shared 98.18% and 94.40% homology with the cattle isolates (FUP12 and FUP9. Conclusions: The results indicated the relationships of P. multocida isolated from buffalo and cattle rather than the close relationships between P. multocida isolated from cattle and sheep. Diagnosis of P. multocida by 16S rDNA and KMT1 gene sequences was important to determine the antigen that is responsible for protective cover within the same group of animals and to help for the production of new vaccines for the control of microbial infection for domestic animals.

Distribution of the ompA-types among ruminant and swine pneumonic strains of Pasteurella multocida exhibiting various cap-locus and toxA patterns.

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Vougidou, C; Sandalakis, V; Psaroulaki, A; Siarkou, V; Petridou, E; Ekateriniadou, L

2015-05-01

Pasteurella multocida is an important pathogen in food-producing animals and numerous virulence genes have been identified in an attempt to elucidate the pathogenesis of pasteurellosis. Currently, some of these genes including the capsule biosynthesis genes, the toxA and the OMPs-encoding genes have been suggested as epidemiological markers. However, the number of studies concerning ruminant isolates is limited, while, no attempt has ever been made to investigate the existence of ompA sequence diversity among P. multocida isolates. The aim of the present study was the comparative analysis of 144 P. multocida pneumonic isolates obtained from sheep, goats, cattle and pigs by determining the distribution of the ompA-types in conjunction with the cap-locus and toxA patterns. The ompA genotypes of the isolates were determined using both a PCR-RFLP method and DNA sequence analysis. The most prevalent capsule biosynthesis gene among the isolates was capA (86.1%); a noticeable, however, rate of capD-positive isolates (38.6%) was found among the ovine isolates that had been associated primarily with the capsule type A in the past. Moreover, an unexpectedly high percentage of toxA-positive pneumonic isolates was noticed among small ruminants (93.2% and 85.7% in sheep and goats, respectively), indicating an important epidemiological role of toxigenic P. multocida for these species. Despite their great heterogeneity, certain ompA-genotypes were associated with specific host species, showing evidence of a host preference. The OmpA-based PCR-RFLP method developed proved to be a valuable tool in typing P. multocida strains. Copyright © 2015 Elsevier GmbH. All rights reserved.

Mutant prevention concentration and PK-PD relationships of enrofloxacin for Pasteurella multocida in buffalo calves.

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Balaje, R M; Sidhu, P K; Kaur, G; Rampal, S

2013-12-01

This study validated the use of mutant prevention concentration (MPC) and pharmacokinetic and pharmacodynamic (PK-PD) modeling approach for optimization of dose regimen of enrofloxacin to contain the emergence of Pasteurella multocida resistance. The PK and PD characteristics of enrofloxacin were investigated in buffalo calves after intramuscular administration at a dose rate of 12 mg/kg. The concentration of enrofloxacin and ciprofloxacin in serum were determined by high-performance liquid chromatography. The serum peak concentration (Cmax), terminal half-life (t1/2K10), volume of distribution (Vd(area)/F) and mean residence time (MRT) of enrofloxacin were 1.89 ± 0.35 μg/ml, 5.14 ± 0.66 h, 5.59 ± 0.99 l/kg/h and 8.52 ± 1.29 h, respectively. The percent metabolite conversion ratio of ciprofloxacin to enrofloxacin was 79. The binding of enrofloxacin to plasma proteins was 11%. The MIC, MBC and MPC for enrofloxacin against P. multocida were 0.05, 0.06 μg/ml and 1.50 μg/ml.In vitro and ex-vivo bactericidal activity of enrofloxacin was concentration dependent. Modeling of ex-vivo growth inhibition data to the sigmoid Emax equation provided AUC24h/MIC values to produce bacteriostatic (19 h), bactericidal (43 h) and bacterial eradication (64 h). PK-PD data in conjunction with MPC and MIC90 data predicted dosage schedules for enrofloxacin that may achieve optimum efficacy in respect of bacteriological and clinical cure and minimize the risk of emergence of resistance. Copyright © 2013 Elsevier Ltd. All rights reserved.

ESTUDIOS DE AISLAMIENTO Y FRACCIONAMIENTO DE UN COMPLEJO GLICOPROTEICO DE PASTEURELLA MULTOCIDA

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Yolanda de Navarro

2010-07-01

Full Text Available Mediante la extracción con solución de NaCl 2.5% (p/v a 47' C, se obtuvo un complejo glicoproteíco de Pasteurella multocida que fue parcialmente purificado mediante filtración por gel usando Sephacryl S-200. Las fracciones 1, 2 y 3 presentaron líneas de precipitinas en imnunodifusión contra sueros hiperimnunes de conejos inoculados con extracto salino 2.5% (P/V a 47" C y 66' C. Por electroforesis SDS-PAGE. se determinaron bandas de proteínas con pesos moleculares entre 98.800 y 17.700 daltons. Lafracción lyel extracto salino crudo a 47" C se utilizaron como antígenos adsorbidos en gel de Al(OHj y con ellos se efectuaron ensayos de protección en ratones, teniendo como referencia la vacuna comercial contra Septicemia Hemorrágica producida por VECOL S.A. Mediante el método estadístico de Reed Muench se estableció el índice de protección y se encontró que todos los antígenos fueron considerados prolectores, siendo la fracción 1 la de mayor índice de protección con una dosis inferior.

A capsule/lipopolysaccharide/MLST genotype D/L6/ST11 of Pasteurella multocida is likely to be strongly associated with swine respiratory disease in China.

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Peng, Zhong; Wang, Haonan; Liang, Wan; Chen, Yibao; Tang, Xibiao; Chen, Huanchun; Wu, Bin

2018-01-01

Pasteurella multocida is a leading cause of respiratory disease in pigs worldwide. In this study, we determined the genetic characteristics of 115 P. multocida isolates from the lungs of pigs with respiratory disease in China in 2015 using capsular typing, lipopolysaccharide (LPS) genotyping, and virulence genotyping based on the detection of virulence-associated genes. The results showed that the isolates belonged to three capsular types: A (49.6%), D (46.1%), and nontypable (4.3%); and two LPS genotypes: L3 (22.6%) and L6 (77.4%). When combining the capsular types with the LPS genotypes, a genotype group D: L6 (46.1%) was the most prevalent among the strains. Among the 23 virulence-associated genes detected in this study, a small number of them displayed a certain level of "genotype-preference". We found that pfhA, hgbA, and hgbB had a close association with P. multocida LPS genotypes, while tadD was more associated with P. multocida capsular types. In addition, multilocus sequence typing (MLST) on 40 P. multocida isolates identified four sequence types: ST3, ST10, ST11, and ST16, and the distribution of ST11 was significantly higher than the other MLST genotypes. Interestingly, all of the ST11 isolates detected in this study were genotype D: L6 strains and they were 100% positive for hgbB. Our data suggest that a capsule/LPS/MLST genotype D/L6/ST11 is likely to be strongly associated with respiratory clinical manifestation of the disease in pigs.

Pasteurella multocida in backyard chickens in Upper Egypt: incidence with polymerase chain reaction analysis for capsule type, virulence in chicken embryos and antimicrobial resistance.

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Mohamed, Moemen A; Mohamed, Mohamed-Wael A; Ahmed, Ahmed I; Ibrahim, Awad A; Ahmed, Mohamed S

2012-01-01

The prevalence of Pasteurella multocida strains among 275 backyard chickens from different regions of Upper Egypt was studied. A total of 21 isolates of P. multocida were recovered in 21 out of 275 chickens tested (7.6%) and were confirmed using phenotypic characterisation. Somatic serotyping of the 21 isolates resulted in 12 isolates being classed as serotype A:1 (57.14%), 4 as serotype A:3 (19.05%) and 5 could not be typed (23.8%). Capsular typing, using multiplex polymerase chain reaction (PCR), demonstrated that 18 strains were capsular type A (85.7%), and 3 were type D (14.3%). The present findings suggest that a multiplex capsular PCR could be valuable for the rapid identification of P. multocida in cases of fowl cholera infection. A total of 5 isolates of P. multocida were selected to study their pathogenicity in embryonated chicken eggs instead of conducting a study in mature chickens. The results showed a variation in pathogenicity between the strains tested, namely: serotype A:1 strains caused 80% mortality, in contrast to 20% mortality by type D strains. Pathological findings included severe congestion of the entire embryo, haemorrhaging of the skin, feather follicles and toe, and ecchymotic haemorrhages on the liver of the inoculated embryos. The observations in this study indicate that P. multocida serogroup A could be highly pathogenic for mature chickens and therefore might be a cause of considerable economic losses in commercial production. A total of 10 isolates were subjected to antimicrobial susceptibility to determine the minimal inhibitory concentration of 7 antimicrobials. All isolates were susceptible to ciprofloxacin, florfenicol, streptomycin and sulphamethoxazol with trimethoprim and with varying degrees of sensitivity to the other agents.

Serological evidence of avian encephalomyelitis virus and Pasteurella multocida infections in free-range indigenous chickens in Southern Mozambique.

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Taunde, Paula; Timbe, Palmira; Lucas, Ana Felicidade; Tchamo, Cesaltina; Chilundo, Abel; Dos Anjos, Filomena; Costa, Rosa; Bila, Custodio Gabriel

2017-06-01

A total of 398 serum samples from free-range indigenous chickens originating from four villages in Southern Mozambique were tested for the presence of avian encephalomyelitis virus (AEV) and Pasteurella multocida (PM) antibodies through commercial enzyme-linked immunosorbent assay (ELISA) kits. AEV and PM antibodies were detected in all villages surveyed. The proportion of positive samples was very high: 59.5% (95% confidence interval (CI) 51.7-67.7%) for AEV and 71.5% (95% CI 67.7-77.3%) for PM. Our findings revealed that these pathogens are widespread among free-range indigenous chickens in the studied villages and may represent a threat in the transmission of AEV and PM to wild, broiler or layer chickens in the region. Further research is warranted on epidemiology of circulating strains and impact of infection on the poultry industry.

The capsule is a virulence determinant in the pathogenesis of Pasteurella multocida M1404 (B:2).

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Boyce, J D; Adler, B

2000-06-01

Capsules from a range of pathogenic bacteria are key virulence determinants, and the capsule has been implicated in virulence in Pasteurella multocida. We have previously identified and determined the nucleotide sequence of the P. multocida M1404 (B:2) capsule biosynthetic locus (J. D. Boyce, J. Y. Chung, and B. Adler, Vet. Microbiol. 72:121-134, 2000). The cap locus consists of 15 genes, which can be grouped into three functional regions. Regions 1 and 3 contain genes proposed to encode proteins involved in capsule export, and region 2 contains genes proposed to encode proteins involved in polysaccharide biosynthesis. In order to construct a mutant impaired in capsule export, the final gene of region 1, cexA, was disrupted by insertion of a tetracycline resistance cassette by allelic replacement. The genotype of the tet(M) OmegacexA mutant was confirmed by Southern hybridization and PCR. The acapsular phenotype was confirmed by immunofluorescence, and the strain could be complemented and returned to capsule production by the presence of a cloned uninterrupted copy of cexA. Wild-type, mutant, and complemented strains were tested for virulence by intraperitoneal challenge of mice; the presence of the capsule was shown to be a crucial virulence determinant. Following intraperitoneal challenge of mice, the acapsular bacteria were removed efficiently from the blood, spleen, and liver, while wild-type bacteria multiplied rapidly. Acapsular bacteria were readily taken up by murine peritoneal macrophages, but wild-type bacteria were significantly resistant to phagocytosis. Both wild-type and acapsular bacteria were resistant to complement in bovine and murine serum.

Pasteurella multocida in backyard chickens in Upper Egypt: incidence with polymerase chain reaction analysis for capsule type, virulence in chicken embryos and antimicrobial resistance

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Moemen A. Mohamed

2012-03-01

Full Text Available The prevalence of Pasteurella multocida strains among 275 backyard chickens from different regions of Upper Egypt was studied. A total of 21 isolates of P. multocida were recovered in 21 out of 275 chickens tested (7.6% and were confirmed using phenotypic characterisation. Somatic serotyping of the 21 isolates resulted in 12 isolates being classed as serotype A:1 (57.14%, 4 as serotype A:3 (19.05% and 5 could not be typed (23.8%. Capsular typing, using multiplex polymerase chain reaction (PCR, demonstrated that 18 strains were capsular type A (85.7%, and 3 were type D (14.3%. The present findings suggest that a multiplex capsular PCR could be valuable for the rapid identification of P. multocida in cases of fowl cholera infection. A total of 5 isolates of P. multocida were selected to study their pathogenicity in embryonated chicken eggs instead of conducting a study in mature chickens. The results showed a variation in pathogenicity between the strains tested, namely: serotype A:1 strains caused 80% mortality, in contrast to 20% mortality by type D strains. Pathological findings included severe congestion of the entire embryo, haemorrhaging of the skin, feather follicles and toe, and ecchymotic haemorrhages on the liver of the inoculated embryos. The observations in this study indicate that P. multocida serogroup A could be highly pathogenic for mature chickens and therefore might be a cause of considerable economic losses in commercial production. A total of 10 isolates were subjected to antimicrobial susceptibility to determine the minimal inhibitory concentration of 7 antimicrobials. All isolates were susceptible to ciprofloxacin, florfenicol, streptomycin and sulphamethoxazol with trimethoprim and with varying degrees of sensitivity to the other agents.

Characterization of Pasteurella multocida involved in rabbit infections

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Massacci, Francesca Romana; Magistrali, Chiara Francesca; Cucco, Lucilla

2018-01-01

In rabbit, P. multocida is considered a predominant pathogenic agent; despite this, few data on the molecular epidemiology are available so far. The aim of this work was to characterize P. multocida isolates from rabbit affected by various diseases in Italy. Comparison was made to reference strains...... belonged to the LPS genotypes 3 (22/39) or 6 (17/39). The clonal relationships of the Italian strains from rabbit had similarity to previously reported rabbit isolates that belonged to ST9, ST74, ST204 and ST206, however, they differed from other rabbit references strains that belonged to six other STs....... In particular, ST9 with capsular type F has been previously reported from diseased rabbit in Czech Republic and ST74 has been observed for older rabbit isolates. ST50 has probably been reported from Spain. ST9 and ST50 have previously also been reported from birds and pig, respectively, whereas ST74 has...

Determination of the minimum inhibitory concentration (MIC and mutant prevention concentration (MPC of selected antimicrobials in bovine and swine Pasteurella multocida, Escherichia coli, and Staphylococcus aureus isolates

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Kateřina Nedbalcová

2015-01-01

Full Text Available We compared the values of the minimum inhibitory concentration (MIC and mutant prevention concentration (MPC values ​​of three antimicrobial agents for 72 bovine isolates of Pasteurella multocida, 80 swine isolates of P. multocida, 80 bovine isolates of Escherichia coli, 80 swine isolates of E. coli, and 80 isolates of Staphylococcus aureus from bovine mastitis. The ratio of MIC90​​/MPC90 which limited mutant selection window (MSW was ≤ 0.12/4 mg/l for enrofloxacin, 0.5/≥ 64 mg/l for florfenicol and 4/≥ 128 mg/l for tulathromycin in bovine P. multocida isolates, ≤ 0.12/2 mg/l for enrofloxacin, 0.5/≥ 64 mg/l for florfenicol and 4/≥ 128 mg/l for tulathromycin in swine P. multocida isolates, 1/16 mg/l for enrofloxacin, 8/≥ 64 mg/l for florfenicol and 8/≥ 128 mg/l for tulathromycin in bovine E. coli isolates, 0.5/16 mg/l for enrofloxacin, ≥ 64/≥ 64 mg/l for florfenicol and 8/≥ 128 mg/l for tulathromycin in swine E. coli isolates, and 0.25/16 mg/l for enrofloxacin, 4/≥ 64 mg/l for florfenicol and 4/≥ 128 mg/l for tulathromycin in S. aureus isolates. These findings indicate that the dosage of antimicrobial agents to achieve serum concentration equal to or higher than MPC could reduce selection of resistant bacterial subpopulation.

Clinico-pathology, hematology and biochemistry responses in buffaloes towards Pasteurella multocida type B: 2 immunogen lypopolysaccharide via oral and intravenous routes of infection.

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Chung, Eric Lim Teik; Abdullah, Faez Firdaus Jesse; Ibrahim, Hayder Hamzah; Marza, Ali Dhiaa; Zamri-Saad, Mohd; Haron, Abdul Wahid; Lila, Mohd Azmi Mohd; Norsidin, Mohd Jefri

2016-02-01

Haemorrhagic septicaemia is a disease caused by Pasteurella multocida serotype B: 2 and E: 2. The organism causes acute, highly fatal septicaemic disease with high morbidity and mortality in cattle and more susceptible in buffaloes. Lipopolysaccharide can be found on the outer cell wall of the organism. Lipopolysaccharide is released during multiplication which leads to inflammatory reaction. It represents the endotoxin of P. multocida type B: 2 and responsible for toxicity in haemorrhagic septicaemia which plays an important role in the pathogenesis of the disease. Therefore, the aim of this study was to investigate the clinical signs, blood parameters, gross post mortem lesions and histopathology changes caused by P. multocida type B:2 immunogen lipopolysaccharide infections initiated through intravenous and oral routes of infection. 9 buffalo heifers were divided equally into 3 treatment groups. Group 1 was inoculated orally with 10 ml of phosphate buffer saline (PBS); Group 2 and 3 were inoculated with 10 ml of lipopolysaccharide broth intravenously and orally respectively. For the clinical signs, there were significant differences (p hematology and biochemistry findings, there were significant differences (p 0.05) in the MCHC, leukocytes, band neutrophils, basophils, thrombocytes, plasma protein, icterus index, total protein, globulin and A:G ratio between intravenous and oral group. For Group 2 buffaloes, there were gross lesions in the lung, trachea, heart, liver, spleen, and kidney. In contrast, lesions were only observed in the lung, trachea and liver of Group 3 buffaloes. There were significant differences (p 0.05) in edema lesion between groups. In conclusion, this study is a proof that oral route infection of P. multocida type B:2 immunogen lipopolysaccharide can be used to stimulate host cell responses where oral vaccine through feed could be developed in the near future. Copyright © 2015 Elsevier Ltd. All rights reserved.

Identificação de transcritos diferencialmente expressos por Pasteurella multocida em condições de privação de ferro

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Mayara I.V. Silva

Full Text Available RESUMO: Ferro (Fe é um elemento essencial e a capacidade de adquiri-lo in vivo têm sido descrita em diversos agentes patogênicos através de fatores de virulência. Análises de transcritos durante a privação de Fe tem sido descritos através da técnica de "microarray", entretanto a técnica de RNA-seq recentemente tem demonstrado resultados superiores. Neste trabalho, o isolado de Pasteurella multocida (Pm 16759 altamente patogênico em suínos foi cultivado em duas condições com diferentes concentrações de Fe (controle e privação com o objetivo de analisar transcritos diferencialmente expressos. O RNA total das duas condições foi extraído e sequenciado através da plataforma de nova geração Ion Torrent. Os dados foram analisados no Software Ion Reporter(tm e processados no programa Rockhopper. Foram obtidas 1.341.615 leituras com tamanho médio de 81pb, com 96% de alinhamento com o genoma de Pasteurella multocida subsp. multocida 3480 e 98,8% de acurácia. No mapeamento das leituras das duas condições, observou-se 2,652 transcritos e destes, 177 (6,7% foram diferencialmente expressos, sendo 93 na condição controle (Fe+ e 84 na condição de privação (Fe-. Na condição de privação de Fe, o perfil de transcritos foram associados a função de transporte celular (fbp ABC, permease de alta afinidade com Fe2+/Pb2+ e proteína periplasmática de alta afinidade com Fe2+ , reguladores transcricionais e proteínas hipotéticas. O perfil na condição controle (Fe+ apresentou transcritos diferencialmente expressos associados ao RNAs anti-sense (asRNA e genes do metabolismo energético (fructose-1,6-bisfosfatase. O estudo comprovou que a restrição de Fe aumenta a expressão de genes envolvidos no transporte celular, reguladores transcricionais, proteínas hipotéticas e desconhecidas e permitiu ainda a identificação de novos genes como a permease de alta afinidade com Fe2+/Pb2+ e proteina periplasmática de alta afinidade

Development of fowl cholera vaccine: I. Protection of Pasteurella multocida local isolate vaccine against challenge of homologous and heterologous strains.

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Supar

2001-03-01

Full Text Available Pasteurella multocida locally isolated from chicken and ducks (BCC 299, BCC 2331, DY1, DY2, 12TG, 15TG andimported strains (BCC 1359, 1362; HEDDLESTON group 1 and 6 respectively had been tested for its pathogenicity in theprevious study. The aims of this experiment were to study the preparation of local isolate pasteurellosis vaccines and to determine the protective effect of that vaccines in chicken against the highly pathogenic local isolates of P. multocida. Killed monovalent, bivalent and polyvalent pasteurellosis vaccines were prepared and each was adjunvanted with aluminum hydroxide gel at a final concentration of 1.5% and the cell concentration was equal to the No 10 of MacFarland tube standard. Each of the vaccine prepared was used to vaccinated on a group of six week old of layer chicken (8 per group. Each chicken was subcutaneously injected with 0.2 ml of vaccine, four weeks later each was boostered with similar vaccine with the same dose. Two weeks after giving the boostered vaccine each group of chicken were challenged, half with life bacterium of P. Multocida BCC 2331 and other with DY2. Any chick which survive after challenge was designated as protected by vaccination. Before vaccination 1 ml of blood was drawn from each of chicken and then two weeks apart up to challenge. Serum from each sample was separated and kept in deep freeze until tested by enzyme-linked immunosorbent assay (ELISA. Chicken vaccinated with killed whole cell P. multocida vaccines of monovalent (BCC 2331 or DY2 and bivalent (BCC 2331 + DY2 were protected against challenge with live bacterium of either BCC 2331 or DY2 at rate 67-100%. There was no protection in chicken vaccinated with either BCC 299, DY1, 12TG, 15TG, BCC 1359, or 1362 killed vaccine. Similarly no protection of chicken vaccinated with either DY1 + BCC299, 12TG + 15TG or BCC 1359 + BCC 1362 bivalent vaccines. The protection rate of the polyvalent local isolate vaccine was at average 50-75%. All

Evaluación de dos técnicas de subtipificación molecular para el estudio de Pasteurella multocida Evaluation of two techniques of molecular subtyping to study Pasteurella multocida

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G. A. Leotta

2006-12-01

Full Text Available Se determinó la tipibilidad, la reproducibilidad y el poder discriminatorio de ERIC-PCR y ApaI-PFGE para establecer la relación genética de cepas de Pasteurella multocida. Se estudiaron 49 cepas de diferente origen, subespecie, biotipo, grupo capsular, serotipo somático y perfil de resistencia antimicrobiana. Por ERIC-PCR se establecieron 31 patrones, los que presentaron entre 10 y 14 bandas en un rango comprendido entre 0,2 y 1,2 kb. Por ApaI-PFGE se detectaron 37 patrones de restricción, los cuales presentaron entre 7 y 15 bandas bien definidas de 34 a 450 kb. La tipibilidad de ERIC-PCR fue del 100% (T=1 y la de ApaI-PFGE del 94% (T=0,94. La reproducibilidad de ambas técnicas fue del 100% (R=1; sin embargo, el poder discriminatorio de ERIC-PCR fue 93% (D=0,93 y el de ApaI-PFGE 98% (D=0,98. Mediante ambas técnicas fue posible agrupar las cepas con relación epidemiológica y diferenciar claramente las cepas no relacionadas. Se demostró el valor de ERIC-PCR y ApaI-PFGE para complementar estudios epidemiológicos, principalmente si las cepas en estudio son analizadas por ambas técnicas.Typeability, reproducibility, and discriminatory power of ERIC-PCR and ApaI-PFGE to establish the genetic relation of P. multocida strains were determined. Forty-nine strains of different source, biotype, capsular group, somatic serotype, and resistance to antimicrobials were studied. By ERIC-PCR, 31 patterns were defined with 10 to 14 bands in a rank of 0.2 and 1.2 kb. By ApaI-PFGE, 37 restriction patterns were established with 7 to 15 bands of 34 to 450 kb. Typeability was 100% (T=1 for ERIC-PCR, and 94% (T=0.94 for ApaI-PFGE. Reproducibility of both techniques was 100% (R=1. Discriminatory power was 93% (D=0.93 for ERIC-PCR, and 98% (D=0.98 for ApaI-PFGE. By using both techniques, epidemiologically related strains were grouped, and unrelated strains were clearly differentiated. The value of ERIC-PCR and ApaI-PFGE as complements to epidemiologic studies

Molecular analysis of Pasteurella multocida strains isolated from fowl cholera infection in backyard chickens

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Mohamed-Wael Abdelazeem Mohamed

2014-01-01

Conclusion: Based on the previous findings, there are three spreading clusters that may indicate the association of a small number of P. multocida variants with the majority of cases suggesting that certain clones of P. multocida are able to colonize the examined backyard chickens. Also, the ease and rapidity of RAPD-PCR support the use of this technique as alternative to the more labour-intensive SDS-PAGE system for strain differentiation and epidemiological studies of avian P. multocida. Further application of RAPD technology to the examination of avian cholera outbreaks in commercially available flocks may facilitate more effective management of this disease by providing the potential to investigate correlations of P. multocida genotypes, to identify affiliations between bird types and bacterial genotypes, and to elucidate the role of specific bird species in disease transmission.

Surveillance of antimicrobial resistance in clinical isolates of Pasteurella multocida and Streptococcus suis from Ontario swine

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Glass-Kaastra, Shiona K.; Pearl, David L.; Reid-Smith, Richard J.; McEwen, Beverly; Slavic, Durda; Fairles, Jim; McEwen, Scott A.

2014-01-01

Susceptibility results for Pasteurella multocida and Streptococcus suis isolated from swine clinical samples were obtained from January 1998 to October 2010 from the Animal Health Laboratory at the University of Guelph, Guelph, Ontario, and used to describe variation in antimicrobial resistance (AMR) to 4 drugs of importance in the Ontario swine industry: ampicillin, tetracycline, tiamulin, and trimethoprim–sulfamethoxazole. Four temporal data-analysis options were used: visualization of trends in 12-month rolling averages, logistic-regression modeling, temporal-scan statistics, and a scan with the “What’s strange about recent events?” (WSARE) algorithm. The AMR trends varied among the antimicrobial drugs for a single pathogen and between pathogens for a single antimicrobial, suggesting that pathogen-specific AMR surveillance may be preferable to indicator data. The 4 methods provided complementary and, at times, redundant results. The most appropriate combination of analysis methods for surveillance using these data included temporal-scan statistics with a visualization method (rolling-average or predicted-probability plots following logistic-regression models). The WSARE algorithm provided interesting results for quality control and has the potential to detect new resistance patterns; however, missing data created problems for displaying the results in a way that would be meaningful to all surveillance stakeholders. PMID:25355992

Comparison of gene expression of Toll-like receptors and cytokines between Piau and Commercial line (Landrace×Large White crossbred) pigs vaccinated against Pasteurella multocida type D.

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Sousa, Katiene Régia Silva; Ribeiro, André Mauric Frossard; Dantas, Waleska de Melo Ferreira; Oliveira, Leandro Licursi de; Gasparino, Eliane; Guimarães, Simone Eliza Facioni

2017-10-01

We aimed to compare Toll-like receptors (TLR) and cytokines expression in local Piau breed and a Commercial line (Landrace×Large White crossbred) pigs in response to vaccination against Pasteurella multocida type D. Seronegative gilts for Pasteurella multocida type D and Mycoplasma hyopneumoniae were used, from which peripheral blood mononuclear cells (PBMC) were collected in four time points (T0, T1, T2 and T3; before and after each vaccination dose). For bronchoalveolar lavage fluid cells (BALF), we set groups of vaccinated and unvaccinated animals for both genetic groups. Gene expression was evaluated on PBMC and BALF. In PBMC, when we analyzed time points within breeds, significant differences in expression for TLRs and cytokines, except TGFβ, were observed for Commercial animals. For the Piau pigs, only TGFβ showed differential expression. Comparing the expression among genetic groups, the Commercial pigs showed higher expression for TLRs after first vaccination dose, while for IL2, IL6, IL12 and IL13, higher expression was also observed in T3 and IL8 and IL10, in T1 and T3. Still comparing the breeds, the crossbred animals showed higher expression for TNFα in T1 and T2, while for TGFβ only in T2. For gene expression in BALF, vaccinated Commercial pigs showed higher expression of TLR6, TLR10, IL6, IL8, IL10, TNFα and TGFβ genes than vaccinated Piau pigs. The Commercial line pigs showed higher sensitivity to vaccination, while in local Piau breed lower responsiveness, which may partly explain genetic variability in immune response and will let us better understand the tolerance/susceptibility for pasteurellosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

[In vitro activity of 12 antibiotics used in veterinary medicine against Mannheimia haemolytica and Pasteurella multocida isolated from calves in the Netherlands].

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Mevius, D J; Hartman, E G

2000-03-01

Results of susceptibility tests of clinical isolates of animal pathogens are periodically summarized and reported by the Animal Health Service. However, these results are based upon qualitative test methods. In the present paper results of quantitative susceptibility tests of twelve antibacterial agents against Mannheimia haemolytica (MHA) and Pasteurella multocida (PMU) isolated from Dutch calves in 1996 and 1997 are presented. Minimum inhibitory concentrations of amoxicillin, ceftiofur, tetracycline, trimethoprim-sulphamethoxazole, tilmicosin, neomycin, gentamicin, spectinomycin, flumequine, enrofloxacin, chloramphenicol and florfenicol were determined. No resistance was detected for ceftiofur and florfenicol. Three strains had an intermediate susceptibility to tilmicosin. The resistance percentages of MHA and PMU for neomycin, gentamicin, spectinomycin, flumequine, enrofloxacin, and chloramphenicol varied from 2% to 16%. Higher resistance percentages (16%-53%) were observed for amoxicillin, tetracycline, and trimethoprim-sulphamethoxazole. The MIC breakpoints used to determine whether a strain is susceptible, intermediate, or resistant are arbitrary and discussed in this paper.

Pasteurella multocida isolated from wild birds of North America: a serotype and DNA fingerprint study of isolates from 1978 to 1993

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Wilson, M.A.; Duncan, R.M.; Nordholm, G.E.; Berlowski, B.M.

1995-01-01

Serotype and DNA fingerprint methods were used to study Pasteurella multocida isolated from 320 wild birds of North America. Isolates were collected during 1978-93. The HhaI profiles of 314 isolates matched the HhaI profile of somatic reference type 1, strain X-73; somatic type 1 antigen was expressed by 310 isolates, and the serotype of four isolates was undetected. Differentiation of the 314 isolates was observed by digestion of DNA with HpaII. None of the HpaII profiles matched the HpaII profile of X-73 (designated HhaI 001/HpaII 001). Three HpaII profiles were recognized among the somatic type 1 isolates: HpaII 002 (n = 18), HpaII 003 (n = 122), and HpaII 004 (n = 174). Profile HpaII 002 was found among isolates collected during 1979-83. Profile HpaII 003 was identified from isolates collected during 1979-89, with the exception of two isolates in 1992. The HpaII 004 profile was identified from isolates collected during 1983-93. Of the six remaining isolates, four expressed somatic type 4 and had HhaI profiles identical to the somatic type 4 reference strain P-1662 profile (designated HhaI 004); these isolates were differentiated by digestion of DNA with HpaII. One isolate was identified as serotype F:11, and another was serotype A:3,4. In the present study, 314 of 316 (99.4%) isolates from wild birds in the Central, Mississippi, and Pacific flyways during 1978-93, were P. multocida somatic type 1.

Cellular defense of the avian respiratory system: effects of Pasteurella multocida on respiratory burst activity of avian respiratory tract phagocytes.

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Ochs, D L; Toth, T E; Pyle, R H; Siegel, P B

1988-12-01

The respiratory tract of healthy chickens contain few free-residing phagocytic cells. Intratracheal inoculation with Pasteurella multocida stimulated a significant (P less than 0.05) migration of cells to the lungs and air sacs of White Rock chickens within 2 hours after inoculation. We found the maximal number of avian respiratory tract phagocytes (22.9 +/- 14.0 x 10(6] at 8 hours after inoculation. Flow cytometric analysis of these cells revealed 2 populations on the basis of cell-size and cellular granularity. One of these was similar in size and granularity to those of blood heterophils. Only this population was capable of generating oxidative metabolites in response to phorbol myristate acetate. The ability of the heterophils to produce hydrogen peroxide, measured as the oxidation of intracellularly loaded 2',7'-dichlorofluorescein, decreased with time after inoculation. These results suggest that the migration of heterophils, which are capable of high levels of oxidative metabolism, to the lungs and air sacs may be an important defense mechanism of poultry against bacterial infections of the respiratory tract.

Demonstration that Australian Pasteurella multocida isolates from sporadic outbreaks of porcine pneumonia are non-toxigenic (toxA-) and display heterogeneous DNA restriction endonuclease profiles compared with toxigenic isolates from herds with progressive atrophic rhinitis.

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Djordjevic, S P; Eamens, G J; Ha, H; Walker, M J; Chin, J C

1998-08-01

Capsular types A and D of Pasteurella multocida cause economic losses in swine because of their association with progressive atrophic rhinitis (PAR) and enzootic pneumonia. There have been no studies comparing whole-cell DNA profiles of isolates associated with these two porcine respiratory diseases. Twenty-two isolates of P. multocida from diseased pigs in different geographic localities within Australia were characterised genotypically by restriction endonuclease analysis (REA) with the enzyme CfoI. Seven of 12 P. multocida isolates from nasal swabs from pigs in herds where PAR was either present or suspected displayed a capsular type D phenotype. These were shown to possess the toxA gene by polymerase chain reaction (PCR) and Southern hybridisation, and further substantiated by production of cytotoxin in vitro. The CfoI profile of one of these seven isolates, which was from the initial outbreak of PAR in Australia (in Western Australia, WA), was identical with profiles of all six other toxigenic isolates from sporadic episodes in New South Wales (NSW). The evidence suggests that the strain involved in the initial outbreak was responsible for the spread of PAR to the eastern states of Australia. Another 10 isolates, representing both capsular types A and D, were isolated exclusively from porcine lung lesions after sporadic outbreaks of enzootic pneumonia in NSW and WA. CfoI restriction endonuclease profiles of these isolates revealed considerable genomic heterogeneity. Furthermore, none of these possessed the toxA gene. This suggests that P. multocida strains with the toxA gene do not have a competitive survival advantage in the lower respiratory tract or that toxin production does not play a role in the pathology of pneumonic lesions, or both. REA with polyacrylamide gel electrophoresis and silver staining was found to be a practical and discriminatory tool for epidemiological tracing of P. multocida outbreaks associated with PAR or pneumonia in pigs.

Hematology of layers chickens vaccinated with fowl cholera vaccine and experimentally inoculated with virulent Pasteurella multocida serotypes in Zaria, Nigeria

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Yusuf Madaki Lekko

2017-09-01

Conclusion The PCV significantly decrease P≤0.05 in layers vaccinated and inoculated with P. multocida but increase in unvaccinated layers inoculated P. multocida. The mean serum ALP concentration significantly increase P≤0.05 in unvaccinated layers inoculated with P. multocida when compared to layers vaccinated and inoculated with P. multocida. [J Adv Vet Anim Res 2017; 4(3.000: 234-240

Auranofin Inhibits the Enzyme Activity of Pasteurella multocida Toxin PMT in Human Cells and Protects Cells from Intoxication

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Stefan Carle

2017-01-01

Full Text Available The AB-type protein toxin from Pasteurella multocida (PMT contains a functionally important disulfide bond within its catalytic domain, which must be cleaved in the host cell cytosol to render the catalytic domain of PMT into its active conformation. Here, we found that the reductive potential of the cytosol of target cells, and more specifically, the activity of the thioredoxin reductase (TrxR is crucial for this process. This was demonstrated by the strong inhibitory effect of the pharmacological TrxR inhibitor auranofin, which inhibited the intoxication of target cells with PMT, as determined by analyzing the PMT-catalyzed deamidation of GTP-binding proteins (G-proteins in the cytosol of cells. The amount of endogenous substrate levels modified by PMT in cells pretreated with auranofin was reduced compared to cells treated with PMT alone. Auranofin had no inhibitory effect on the activity of the catalytic domain of constitutively active PMT in vitro, demonstrating that auranofin did not directly inhibit PMT activity, but interferes with the mode of action of PMT in cells. In conclusion, the results show that TrxR is crucial for the mode of action of PMT in mammalian cells, and that the drug auranofin can serve as an efficient inhibitor, which might be a starting point for novel therapeutic options against toxin-associated diseases.

Antimicrobial susceptibility, serotypes and genotypes of Pasteurella multocida isolates associated with swine pneumonia in Taiwan.

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Yeh, Jih-Ching; Lo, Dan-Yuan; Chang, Shao-Kuang; Chou, Chi-Chung; Kuo, Hung-Chih

2017-09-21

Pasteurella multocida (PM) can cause progressive atrophic rhinitis and suppurative bronchopneumonia in pigs. The present study performed antimicrobial susceptibility testing and serotype and genotype identification on the 62 PM strains isolated from the lungs of diseased pigs with respiratory symptoms. Antimicrobial susceptibility testing examined 13 antimicrobial agents (amoxicillin, cefazolin, doxycycline, flumequine, enrofloxacin, florfenicol, kanamycin, lincomycin, Linco-Spectin (lincomycin and spectinomycin), erythromycin, tylosin, tilmicosin and tiamulin). Antimicrobial resistance ratios were over 40% in all of the antimicrobial agents except for cefazolin. The highest levels of resistance (100%) were found for kanamycin, erythromycin and tylosin. The majority of isolated strains was serotype D:L6 (n=35) followed by A:L3 (n=17). Comparison of the antimicrobial resistance levels between the two serotypes showed that the antimicrobial resistance rates were higher in D:L6 than in A:L3 for all the tested antimicrobials except for tylosin and tilmicosin. For PM with erm (B), erm (T) or erm (42), the results showed no significant difference compared with non-resistance gene strains in phenotype. Pulsed-field gel electrophoresis genotyping using Apa I restriction digestion of the genomic DNA demonstrated that there were 17 distinct clusters with a similarity of 85% or more, and the genotyping result was similar to that of serotyping. The results of the present study demonstrated that the PM isolated from diseased pigs in Taiwan was resistant to multiple antimicrobials, and the distribution of antimicrobial resistance was associated with pulsotype and serotype. © British Veterinary Association (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Arf6-Dependent Intracellular Trafficking of Pasteurella multocida Toxin and pH-Dependent Translocation from Late Endosomes

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Tracy P. M. Chong

2011-03-01

Full Text Available The potent mitogenic toxin from Pasteurella multocida (PMT is the major virulence factor associated with a number of epizootic and zoonotic diseases caused by infection with this respiratory pathogen. PMT is a glutamine-specific protein deamidase that acts on its intracellular G-protein targets to increase intracellular calcium, cytoskeletal, and mitogenic signaling. PMT enters cells through receptor-mediated endocytosis and then translocates into the cytosol through a pH-dependent process that is inhibited by NH4Cl or bafilomycin A1. However, the detailed mechanisms that govern cellular entry, trafficking, and translocation of PMT remain unclear. Co-localization studies described herein revealed that while PMT shares an initial entry pathway with transferrin (Tfn and cholera toxin (CT, the trafficking pathways of Tfn, CT, and PMT subsequently diverge, as Tfn is trafficked to recycling endosomes, CT is trafficked retrograde to the ER, and PMT is trafficked to late endosomes. Our studies implicate the small regulatory GTPase Arf6 in the endocytic trafficking of PMT. Translocation of PMT from the endocytic vesicle occurs through a pH-dependent process that is also dependent on both microtubule and actin dynamics, as evidenced by inhibition of PMT activity in our SRE-based reporter assay, with nocodazole and cytochalasin D, respectively, suggesting that membrane translocation and cytotoxicity of PMT is dependent on its transfer to late endosomal compartments. In contrast, disruption of Golgi-ER trafficking with brefeldin A increased PMT activity, suggesting that inhibiting PMT trafficking to non-productive compartments that do not lead to translocation, while promoting formation of an acidic tubulovesicle system more conducive to translocation, enhances PMT translocation and activity.

Feeding of waste milk to Holstein calves affects antimicrobial resistance of Escherichia coli and Pasteurella multocida isolated from fecal and nasal swabs.

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Maynou, G; Bach, A; Terré, M

2017-04-01

The use of milk containing antimicrobial residues in calf feeding programs has been shown to select for resistant fecal Escherichia coli in dairy calves. However, information is scarce about the effects of feeding calves waste milk (WM) on the prevalence of multidrug-resistant bacteria. The objective of this study was to determine the antimicrobial resistance patterns of fecal E. coli and nasal Pasteurella multocida isolates from calves fed either milk replacer (MR) or WM in 8 commercial dairy farms (4 farms per feeding program). Fecal and nasal swabs were collected from 20 ± 5 dairy calves at 42 ± 3.2 d of age, and from 10 of these at approximately 1 yr of age in each study farm to isolate the targeted bacteria. Furthermore, resistance of E. coli isolates from calf-environment and from 5 calves at birth and their dams was also evaluated in each study farm. Resistances were tested against the following antimicrobial agents: amoxicillin-clavulanic acid, ceftiofur, colistin, doxycycline (DO), enrofloxacin (ENR), erythromycin, florfenicol, imipenem, and streptomycin. A greater number of fecal E. coli resistant to ENR, florfenicol, and streptomycin and more multidrug-resistant E. coli phenotypes were isolated in feces of calves fed WM than in those fed MR. However, the prevalence of fecal-resistant E. coli was also influenced by calf age, as it increased from birth to 6 wk of age for ENR and DO and decreased from 6 wk to 1 yr of age for DO regardless of the feeding program. From nasal samples, an increase in the prevalence of colistin-resistant P. multocida was observed in calves fed WM compared with those fed MR. The resistance patterns of E. coli isolates from calves and their dams tended to differ, whereas similar resistance profiles among E. coli isolates from farm environment and calves were observed. The findings of this study suggest that feeding calves WM fosters the presence of resistant bacteria in the lower gut and respiratory tracts of dairy calves

Characterization of Pasteurella multocida associated with ovine pneumonia using multi-locus sequence typing (MLST) and virulence-associated gene profile analysis and comparison with porcine isolates.

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García-Alvarez, Andrés; Vela, Ana Isabel; San Martín, Elvira; Chaves, Fernando; Fernández-Garayzábal, José Francisco; Lucas, Domínguez; Cid, Dolores

2017-05-01

Pasteurella multocida is a pathogen causing disease in a wide range of hosts including sheep and pigs. Isolates from ovine pneumonia were characterized by MLST (Multi-host and RIRDC databases) and virulence-associated gene (VAG) typing and compared with porcine isolates. Ovine and porcine isolates did not share any STs as determined by both schemes and exhibited different VAG profiles. With the Multi-host database, sixteen STs were identified among 43 sheep isolates with two STs (ST50 and ST19) comprising 53.5% of the isolates, and seven MLST genotypes (ST3, ST11 and ST62 included 75% of the isolates) among the 48 pig isolates. The most frequent VAG profile among sheep isolates was tbpA+/toxA+ (69.8% of isolates) and pfhA+ (62.5%) and hgbB+ (33.3%) among pig isolates. Representative ovine and porcine isolates of those STs identified by the Multi-host scheme were further typed using the RIRDC scheme. Seven STs were identified among the ovine isolates (ST95 RIRDC , ST131 RIRDC , ST203 RIRDC , ST320 RIRDC , ST324 RIRDC , ST321 RIRDC , and ST323 RIRDC ), with the latter four sequence types being new STs identified in this study, and six STs (ST9 RIRDC , ST13 RIRDC , ST27 RIRDC , ST50 RIRDC , and ST74 RIRDC and a new sequence type ST322 RIRDC ) among the porcine isolates. STs identified among ovine isolates have been detected exclusively in small ruminants, suggesting an adaptation to these hosts, while the genotypes identified among pig isolates have been previously identified in multiple hosts and therefore they are not restricted to pigs. The differences in genotypes and VAG profiles between ovine and pig isolates suggest they could represent different subpopulations of P. multocida. Copyright © 2017 Elsevier B.V. All rights reserved.

ORF Alignment: NC_002663 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available NC_002663 gi|15602008 >1p3dA 1 463 17 479 e-156 ... ref|NP_245080.1| MurC [Pasteurell...a multocida subsp. multocida str. Pm70] ... gb|AAK02227.1| MurC [Pasteurella multocida subsp. ...

Utilización de lectinas en la inhibición de la adhesión de Pasteurella multocida

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Magda Patricia Carrillo Lamus

2013-06-01

Full Text Available El primer paso de la infección es la adhesión de los organismos patógenos a las células blanco. Esta característica les permite no solo penetrar y desplegar las estrategias ofensivas para iniciar la colonización, sino contribuir a la protección y el resguardo de estos a los mecanismos de defensa tanto inmunológicos como mecánicos del hospedero. Este proceso se lleva a cabo en gran medida por la interacción de lectinas, que son proteínas de origen no inmune con la capacidad de reconocer y aglutinar carbohidratos. Este mecanismo ha sido reportado para muchos microorganismos como virus y bacterias. En el caso particular de la Pasteurella multocida, que es una bacteria gramnegativa, patógena oportunista, que inicia la infección en el epitelio respiratorio de muchos animales, se han descrito sobre su superficie sustancias lectinas como la fimbria tipo IV y carbohidratos como el lipopolisacárido o la cápsula que reconocen carbohidratos y lectinas, respectivamente, sobre la superficie de las células epiteliales del tubo respiratorio, circunstancia que le permite adherirse y resguardarse del efecto mucociliar. Debido a que para la gran mayoría de estos microorganismos —incluida P. multocida— es evidente la disminución de la susceptibilidad a los antibacterianos y a la efectividad de las vacunas, se han buscado nuevas tácticas terapéuticas y profilácticas con el fin de interrumpir la infección de los patógenos por medio del bloqueo por competencia de la unión carbohidratos-lectina, donde se ve disminuida la unión del microorganismo al tejido y, por consiguiente, la infección.

Specific detection of Pasteurella multocida in chickens with fowl cholera and in pig lung tissues using fluorescent rRNA in situ hybridization

DEFF Research Database (Denmark)

Mbuthia, P.G.; Christensen, H.; Boye, Mette

2001-01-01

in formalin-fixed paraffin-embedded lung tissues from experimental fowl cholera in chickens and infections in pigs. In chicken lung tissues P. multocida cells were detected singly, in pairs, as microcolonies, and as massive colonies within air capillaries (septa and lumen), parabronchial septa, and blood...... and fast method for specific detection of P. multocida in histological formalin-fixed tissues. The test was replicable and reproducible and is recommended as a supplementary test for diagnosis and as a tool in pathogenesis studies of fowl cholera and respiratory tract infections in pigs due to P. multocida....

Mannan-binding lectin (MBL) in two chicken breeds and the correlation with experimental Pasteurella multocida infection

DEFF Research Database (Denmark)

Schou, Torben Wilde; Permin, Anders; Christensen, Jens Peter

2010-01-01

of the chickens, suggesting that MBL plays an important role against P. multocida. A statistically significant negative correlation was found between the specific antibody response and the genetic serum MBL concentration for both breeds. This indicates that MBL in chickens is capable of acting as the first line...

21 CFR 520.2218 - Sulfamerazine, sulfamethazine, and sulfaquinoxaline powder.

Science.gov (United States)

2010-04-01

...) As an aid in the control of acute fowl cholera caused by Pasteurella multocida susceptible to... days. If disease recurs, repeat treatment. (ii) Limitations. Make fresh solution daily. Do not treat... acute fowl cholera caused by Pasteurella multocida susceptible to sulfamerazine, sulfamethazine, and...

Molecular diagnosis of Haemorrhagic Septicaemia - A Review

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Ranjan Rajeev

2011-08-01

Full Text Available Pasteurella multocida is associated with hemorrhagic septicaemia in cattle and buffaloes, pneumonic pasteurellosis in sheep and goats, fowl cholera in poultry, atrophic rhinitis in pigs and snuffles in rabbits. Haemorrhagic septicaemia is caused by Pasteurella multocida type B:2, B:2,5 and B:5 in Asian countries and type E:2 in African countries. Pasteurella multocida have five types of capsular serotype i.e. type A, B, D, E and F. Diagnosis of the disease is mainly based on the clinical sign and symptom, post mortem findings. Confirmatory diagnosis is done by isolation and identification of causative agent. A variety of laboratory diagnostic techniques have been developed over the years for pasteurellosis and used routinely in the laboratory. Among these techniques molecular techniques of diagnosis is most important. This technique not only gives diagnosis but it also provides information regarding capsular type of Pasteurella multocida. Techniques which are used for molecular diagnosis of haemorrhagic septicaemia are PCR based diagnosis, Restriction endonuclease analysis (REA, Ribotyping, Colony hybridization assay, Filled alternation gel electrophoresis (FAGE, Detection of Pasteurella multocida by Real Time PCR. Among these techniques real time PCR is most sensitive and specific. [Vet. World 2011; 4(4.000: 189-192

Pasteurella multocida from outbreaks of avian cholera in wild and captive birds in Denmark

DEFF Research Database (Denmark)

Pedersen, Karl; Dietz, Hans-Henrik; Jørgensen, J.C.

2003-01-01

An outbreak of avian cholera was observed among wild birds in a few localities in Denmark in 2001. The highest mortalities were among breeding ciders (Somateria mollissima) and gulls (Larus spp.). Pulsed-field gel electrophoresis (PFGE) was conducted using ApaI and SmaI as restriction enzymes...... the outbreak strain. Among 68 isolates from wild birds, only one PFGE and one REA pattern were demonstrated, whereas among 23 isolates from domestic poultry, 14 different SmaI, 12 different ApaI, and 10 different HpaII patterns were found. The results suggest that a P. multocida strain has survived during...

Virulence Genotyping of Pasteurella multocida Isolated from Multiple Hosts from India

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Laxmi Narayan Sarangi

2014-01-01

Full Text Available In this study, 108 P. multocida isolates recovered from various host animals such as cattle, buffalo, swine, poultry (chicken, duck, and emu and rabbits were screened for carriage of 8 virulence associated genes. The results revealed some unique information on the prevalence of virulence associated genes among Indian isolates. With the exception of toxA gene, all other virulence associated genes were found to be regularly distributed among host species. Association study between capsule type and virulence genes suggested that pfhA, nanB, and nanH genes were regularly distributed among all serotypes with the exception of CapD, whereas toxA gene was found to be positively associated with CapD and CapA. The frequency of hgbA and nanH genes among swine isolates of Indian origin was found to be less in comparison to its equivalents around the globe. Interestingly, very high prevalence of tbpA gene was observed among poultry, swine, and rabbit isolates. Likewise, very high prevalence of pfhA gene (95.3% was observed among Indian isolates, irrespective of host species origin.

Virulence genotyping of Pasteurella multocida isolated from multiple hosts from India.

Science.gov (United States)

Sarangi, Laxmi Narayan; Priyadarshini, Adyasha; Kumar, Santosh; Thomas, Prasad; Gupta, Santosh Kumar; Nagaleekar, Viswas Konasagara; Singh, Vijendra Pal

2014-01-01

In this study, 108 P. multocida isolates recovered from various host animals such as cattle, buffalo, swine, poultry (chicken, duck, and emu) and rabbits were screened for carriage of 8 virulence associated genes. The results revealed some unique information on the prevalence of virulence associated genes among Indian isolates. With the exception of toxA gene, all other virulence associated genes were found to be regularly distributed among host species. Association study between capsule type and virulence genes suggested that pfhA, nanB, and nanH genes were regularly distributed among all serotypes with the exception of CapD, whereas toxA gene was found to be positively associated with CapD and CapA. The frequency of hgbA and nanH genes among swine isolates of Indian origin was found to be less in comparison to its equivalents around the globe. Interestingly, very high prevalence of tbpA gene was observed among poultry, swine, and rabbit isolates. Likewise, very high prevalence of pfhA gene (95.3%) was observed among Indian isolates, irrespective of host species origin.

The origin of Pasteurella multocida impacts pathology and inflammation when assessed in a mouse model

DEFF Research Database (Denmark)

Pors, Susanne E.; Chadfield, Mark S.; Sorensen, Dorte B.

2016-01-01

dose dependent and consisted of exudative bronchopneumonia, abscess formation in liver and a lower bacterial load in lung and liver. Both isolates caused increased expression of MMP9 and TIMP1. In conclusion, evaluation and comparison of pathogenicity and host-pathogen interaction of P. multocida......) of an isolate from porcine pneumonia or fowl cholera showed marked differences between the two isolates. The avian isolate was highly pathogenic with severe signs of necrotizing pneumonia, liver necrosis and high bacterial load in lung and liver. Clinical signs and pathology related to the porcine isolate were...

The ability of lipopolysaccharide (LPS) of Pasteurella multocida B:2 to induce clinical and pathological lesions in the nervous system of buffalo calves following experimental inoculation.

Science.gov (United States)

Marza, Ali Dhiaa; Jesse Abdullah, Faez Firdaus; Ahmed, Ihsan Muneer; Teik Chung, Eric Lim; Ibrahim, Hayder Hamzah; Zamri-Saad, Mohd; Omar, Abdul Rahman; Abu Bakar, Md Zuki; Saharee, Abdul Aziz; Haron, Abdul Wahid; Alwan, Mohammed Jwaid; Mohd Lila, Mohd Azmi

2017-03-01

Lipopolysaccharide (LPS) of P. multocida B:2, a causative agent of haemorrhagic septicaemia (HS) in cattle and buffaloes, is considered as the main virulence factor and contribute in the pathogenesis of the disease. Recent studies provided evidences about the involvement of the nervous system in pathogenesis of HS. However, the role of P. multocida B:2 immunogens, especially the LPS is still uncovered. Therefore, this study was designed to investigate the role of P. multocida B:2 LPS to induce pathological changes in the nervous system. Nine eight-month-old, clinically healthy buffalo calves were used and distributed into three groups. Calves of Group 1 and 2 were inoculated orally and intravenously with 10 ml of LPS broth extract represent 1 × 10 12  cfu/ml of P. multocida B:2, respectively, while calves of Group 3 were inoculated orally with 10 ml of phosphate buffer saline as a control. Significant differences were found in the mean scores for clinical signs, post mortem and histopathological changes especially in Group 2, which mainly affect different anatomic regions of the nervous system, mainly the brain. On the other hand, lower scores have been recorded for clinical signs, gross and histopathological changes in Group 1. These results provide for the first time strong evidence about the ability of P. multocida B:2 LPS to cross the blood brain barrier and induce pathological changes in the nervous system of the affected buffalo calves. Copyright © 2017 Elsevier Ltd. All rights reserved.

In vitro activity of flumequine in comparison with several other antimicrobial agents against five pathogens isolated in calves in The Netherlands.

Science.gov (United States)

Mevius, D J; Breukink, H J; van Miert, A S

1990-10-01

The in vitro activity of flumequine in comparison with several other drugs was tested against 17 P. multocida, 16 P. haemolytica, 21 S. dublin, 21 S. typhimurium and 21 E. coli strains, isolated in (veal) calves in the Netherlands. The MIC50 of flumequine for the respective pasteurellas was 0.25 and 1 microgram/ml, for the salmonellas and E. coli 0.5 micrograms/ml. In comparison with flumequine, enrofloxacin and ciprofloxacin showed higher in vitro activity, with MIC50 less than or equal to 0.008 micrograms/ml for ciprofloxacin. Decreased susceptibility of the pasteurellas was found for kanamycin, neomycin, streptomycin, gentamicin, oxytetracycline and doxycycline. The MIC50 of minocycline for P. multocida was 0.5 micrograms/ml and there was no cross resistance with the other tetracyclines. P. multocida was very susceptible to ampicillin (MIC50 less than or equal to 0.03 micrograms/ml), P. haemolytica, however, was 100% resistant to this drug. Both pasteurellas were susceptible to cephalothin and approximately 50% of the strains of both bacteria were resistant to chloramphenicol. The MIC50 of either spiramycin or tylosin was greater than or equal to their respective breakpoint-MIC values. Both pasteurellas were susceptible to the combination of trimethoprim and sulphamethoxazole. However, for P. multocida, the addition of sulphamethoxazole to trimethoprim had no synergistic effect on its MIC. In comparison with trimethorpim, aditoprim was less potent. Therefore only P. multocida was susceptible to aditoprim.

Aspectos patológicos e microbiológicos das doenças respiratórias em suínos de terminação no Brasil

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Marcos A.Z. Morés

2015-08-01

Full Text Available Resumo: Para avaliação dos aspectos patológicos e microbiológicos de casos clínicos de doenças respiratórias em suínos de terminação foram analisados 75 suínos doentes oriundos de 36 lotes. Suínos que apresentavam sinais clínicos respiratórios evidentes foram necropsiados para avaliação macroscópica e colheita de amostras para análise histopatológica e microbiológica. Foram realizados testes de isolamento bacteriano para as principais bactérias do sistema respiratório dos suínos, PCR para Mycoplasma hyorhinis, imuno-histoquímica para Influenza A, Circovirus suíno tipo 2 e Mycoplasma hyopneumoniae. A sensibilidade antimicrobiana de 24 amostras de Pasteurella multocida tipo A foi avaliada por testes de concentração inibitória mínima para os principais antimicrobianos utilizados em suinocultura. Mycoplasma hyopneumoniae e Pasteurella multocida tipo A foram os agentes infecciosos mais prevalentes. Broncopneumonia supurativa e pleurite foram as principais lesões respiratórias encontradas. Pasteurella multocida tipo A, quando presente, aumentou a extensão das lesões pulmonares. Todas as amostras de Pasteurella multocida testadas foram sensíveis aos antimicrobianos Doxiciclina, Enrofloxacina e Tilmicosina. Em 58% das amostras foi identificado mais de um agente infeccioso, evidenciando a alta prevalência da associação de agentes nas doenças respiratórias de suínos em terminação.

One-Step Multiplex RT-qPCR Assay for the detection of Peste des petits ruminants virus, Capripoxvirus, Pasteurella multocida and Mycoplasma capricolum subspecies (ssp.) capripneumoniae

International Nuclear Information System (INIS)

Settypalli, T.B.K.; Lamien, C.; Spergser, J.; Lelenta, M.; Wade, A.; Gelaye, E.; Loitsch, A.; Minoungou, G.; Thiaucourt, F.; Diallo, A.

2016-01-01

Full text: Respiratory infections, although showing common clinical symptoms like pneumonia, are caused by bacterial, viral or parasitic agents. These are often reported in sheep and goats populations and cause huge economic losses to the animal owners in developing countries. Detection of these diseases is routinely done using ELISA or microbiological methods which are being reinforced or replaced by molecular based detection methods including multiplex assays, where detection of different pathogens is carried out in a single reaction. In the present study, a one-step multiplex RT-qPCR assay was developed for simultaneous detection of Capripoxvirus (CaPV), Peste de petits ruminants virus (PPRV), Pasteurella multocida (PM) and Mycoplasma capricolum ssp. capripneumonia (Mccp) in pathological samples collected from small ruminants with respiratory disease symptoms. The test performed efficiently without any cross-amplification. The multiplex PCR efficiency was 98.31%, 95.48%, 102.77% and 91.46% whereas the singleplex efficiency was 93.43%, 98.82%, 102.55% and 92.0% for CaPV, PPRV, PM and Mccp, respectively. The correlation coefficient was greater than 0.99 for all the targets in both multiplex and singleplex. Based on cycle threshold values, intra and inter assay variability, ranged between the limits of 2%–4%, except for lower concentrations of Mccp. The detection limits at 95% confidence interval (CI) were 12, 163, 13 and 23 copies/reaction for CaPV, PPRV, PM and Mccp, respectively. The multiplex assay was able to detect CaPVs from all genotypes, PPRV from the four lineages, PM and Mccp without amplifying the other subspecies of mycoplasmas. The discriminating power of the assay was proven by accurate detection of the targeted pathogen (s) by screening 58 viral and bacterial isolates representing all four targeted pathogens. Furthermore, by screening 81 pathological samples collected from small ruminants showing respiratory disease symptoms, CaPV was detected in

One-Step Multiplex RT-qPCR Assay for the Detection of Peste des petits ruminants virus, Capripoxvirus, Pasteurella multocida and Mycoplasma capricolum subspecies (ssp. capripneumoniae.

Directory of Open Access Journals (Sweden)

Tirumala Bharani Kumar Settypalli

Full Text Available Respiratory infections, although showing common clinical symptoms like pneumonia, are caused by bacterial, viral or parasitic agents. These are often reported in sheep and goats populations and cause huge economic losses to the animal owners in developing countries. Detection of these diseases is routinely done using ELISA or microbiological methods which are being reinforced or replaced by molecular based detection methods including multiplex assays, where detection of different pathogens is carried out in a single reaction. In the present study, a one-step multiplex RT-qPCR assay was developed for simultaneous detection of Capripoxvirus (CaPV, Peste de petits ruminants virus (PPRV, Pasteurella multocida (PM and Mycoplasma capricolum ssp. capripneumonia (Mccp in pathological samples collected from small ruminants with respiratory disease symptoms. The test performed efficiently without any cross-amplification. The multiplex PCR efficiency was 98.31%, 95.48%, 102.77% and 91.46% whereas the singleplex efficiency was 93.43%, 98.82%, 102.55% and 92.0% for CaPV, PPRV, PM and Mccp, respectively. The correlation coefficient was greater than 0.99 for all the targets in both multiplex and singleplex. Based on cycle threshold values, intra and inter assay variability, ranged between the limits of 2%-4%, except for lower concentrations of Mccp. The detection limits at 95% confidence interval (CI were 12, 163, 13 and 23 copies/reaction for CaPV, PPRV, PM and Mccp, respectively. The multiplex assay was able to detect CaPVs from all genotypes, PPRV from the four lineages, PM and Mccp without amplifying the other subspecies of mycoplasmas. The discriminating power of the assay was proven by accurate detection of the targeted pathogen (s by screening 58 viral and bacterial isolates representing all four targeted pathogens. Furthermore, by screening 81 pathological samples collected from small ruminants showing respiratory disease symptoms, CaPV was detected in

Effect of radiation on bacterial cells pathogenesis

International Nuclear Information System (INIS)

Szulc, M.; Tropilo, J.; Zajaczkowska, E.

1983-01-01

In order to determine the effect of X rays on the pathogeny of Erysipelothrix rhusiopathiae and Pasteurella multocida 334 mice were infected subcutaneously with the germs exposed to 10 Gy and D 10 . It was found that a single exposition of E. rhusiopathiae and P. multocida to 10 Gy and D 10 did not change pathogenic properties of these cells. P. multocida showed higher sensitivity to X rays: D 10 for that species was 94 Gy and for E. rhusiopathiae - 156 Gy. (author)

Bacteremia and Peritonitis in a Patient With Cirrhosis: A Life-Threatening Case From a Prick of a Cactus

Directory of Open Access Journals (Sweden)

Jodi-Anne Wallace MD

2017-08-01

Full Text Available A 58-year-old male with nonalcoholic steatohepatitis cirrhosis presents with right lower extremity cellulitis, abdominal tenderness, and severe sepsis after sustaining puncture injury from a cactus on a property with feral cats. Blood cultures and diagnostic paracentesis were consistent with spontaneous bacterial peritonitis due to Pasteurella multocida , a gram-negative coccobacillus found in the respiratory tract of domestic animals. The patient received timely antibiotic coverage with resolution of spontaneous bacterial peritonitis and sepsis after 14-day treatment. This case emphasizes the life-threatening nature of systemic Pasteurella multocida infection as well as an indirect way of acquiring a zoonotic infection in a patient with end-stage liver disease.

Demonstration of Ornithobacterium rhinotracheale in pheasants (Phasianus colchicus) with pneumonia and airsacculitis

DEFF Research Database (Denmark)

Welchman, D. de B.; Ainsworth, H. L.; Jensen, Tim Kåre

2013-01-01

type 2, avian coronavirus, Mycoplasma gallisepticum, Mycoplasma synoviae and other Mycoplasma species, Escherichia coli, Pasteurella multocida, other Pasteurellaceae and Syngamus trachea, suggesting synergism with other agents. Exposure to other intercurrent factors, including adverse weather...

Indução de empiema em ratos através da inoculação pleural de bactérias Experimental empyema in rats through intrapleural injection of bacteria

Directory of Open Access Journals (Sweden)

José Carlos Fraga

2001-12-01

Full Text Available OBJETIVOS: avaliar a indução experimental de empiema em ratos, através da inoculação intrapleural de duas bactérias (Pasteurella multocida e Staphylococcus aureus, utilizando técnica cirúrgica simples e de fácil execução. MÉTODOS: foram utilizados 24 ratos albinos da raça Wistar, de ambos os sexos, pesando entre 250 e 300g, que, após a anestesia geral, foram submetidos à toracotomia anterior direita, afastamento da musculatura e inoculação de 0,2ml de solução, conforme descrição a seguir: grupo I (n=12, inoculação de Pasteurella multocida, 10(10 unidades formadoras de colônia/ml cultivados em caldo cérebro-coração; grupo II (n=8, inoculação de Staphylococcus aureus, 10(10 unidades formadoras de colônia/ml cultivados em caldo cérebro-coração; e grupo III (n=4, inoculação de caldo cérebro-coração estéril (controle. Os animais foram sacrificados em até 7 dias e a intensidade da reação pleural, analisada macroscopicamente conforme escala padronizada. Também foram avaliados a mortalidade, o volume de líquido na cavidade pleural e o exame bacteriológico (animais mortos e líquido pleural. RESULTADOS: no grupo I (Pasteurella multocida, sete ratos morreram nas primeiras 48 horas de experimento. Cinco ratos foram sacrificados no período programado, mas nenhum deles apresentava empiema. No grupo II (Staphylococcus aureus, somente um animal morreu nas primeiras 24 horas, os outros 7 (88% foram sacrificados e apresentavam empiema. No grupo III, considerados controles, todos os animais sobreviveram, não se observando nenhuma anormalidade torácica ao sacrifício. Analisando conjuntamente os grupos, a indução de empiema esteve associada de maneira significativa à inoculação de Staphylococcus aureus no espaço pleural (p OBJECTIVE: to evaluate empyema formation in rats through the injection of two bacteria (Pasteurella multocida and Staphylococcus aureus, using a simple, easy-to-use surgical technique

Disease: H00306 [KEGG MEDICUS

Lifescience Database Archive (English)

Full Text Available found in the animal's oral cavity. Disseminated Pasteurella infections can lead to serious diseases including septic shock and menin...gitis mostly in infants and pregnant women. Many patients with P. multocida-related

21 CFR 558.586 - Sulfaquinoxaline.

Science.gov (United States)

2010-04-01

... use. As an aid in the control of acute fowl cholera caused by Pasteurella multocida susceptible to.... Treatment to be started after weaning. Feed continuously for 30 days or feed medicated feed for 2 days out...

Avian cholera

Science.gov (United States)

Friend, Milton

1999-01-01

Avian cholera is a contagious disease resulting from infection by the bacterium Pasteurella multocida. Several subspecies of bacteria have been proposed for P. multocida, and at least 16 different P. multocida serotypes or characteristics of antigens in bacterial cells that differentiate bacterial variants from each other have been recognized. The serotypes are further differentiated by other methods, including DNA fingerprinting. These evaluations are useful for studying the ecology of avian cholera (Fig. 7.1), because different serotypes are generally found in poultry and free-ranging migratory birds. These evaluations also show that different P. multocida serotypes are found in wild birds in the eastern United States than those that are found in the birds in the rest of the Nation (Fig. 7.2).

Inhibition of protein synthesis on the ribosome by tildipirosin compared with other veterinary macrolides

DEFF Research Database (Denmark)

Andersen, Niels Møller; Poehlsgaard, Jacob; Warrass, Ralf

2012-01-01

Tildipirosin is a 16-membered-ring macrolide developed to treat bacterial pathogens, including Mannheimia haemolytica and Pasteurella multocida, that cause respiratory tract infections in cattle and swine. Here we evaluated the efficacy of tildipirosin at inhibiting protein synthesis...

The isolation and antibiogram of aerobic nasal bacterial flora of ...

African Journals Online (AJOL)

The following microorganisms were identified from the normal flora of the grasscutters, they are; Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus sp, Micrococcus sp, Bacillus cerus , E. coli, Serratia sp, Streptococcus sp, Pasteurella multocida, Streptacoccus, sp., Mannheimia heamolytica, Klebsiella sp., ...

Quantification and characterization of enzymatically produced hyaluronan with fluorophore-assisted carbohydrate electrophoresis

NARCIS (Netherlands)

Kooy, F.K.; Muyuan Ma,; Beeftink, H.H.; Eggink, G.; Tramper, J.; Boeriu, C.G.

2009-01-01

Hyaluronan (HA) is a polysaccharide with high-potential medical applications, depending on the chain length and the chain length distribution. Special interest goes to homogeneous HA oligosaccharides, which can be enzymatically produced using Pasteurella multocida hyaluronan synthase (PmHAS). We

21 CFR 558.630 - Tylosin and sulfamethazine.

Science.gov (United States)

2010-04-01

... grams sulfamethazine. (2) Indications for use-(i) Maintaining weight gains and feed efficiency in the presence of atrophic rhinitis; lowering the incidence and severity of Bordetella bronchiseptica rhinitis... (Pasteurella multocida and/or Corynebacterium pyogenes); for reducing the incidence of cervical lymphadenitis...

75 FR 1274 - Implantation or Injectable Dosage Form New Animal Drugs; Florfenicol and Flunixin

Science.gov (United States)

2010-01-11

... flunixin meglumine), a combination injectable solution, for treatment of bovine respiratory disease (BRD... treatment of bovine respiratory disease (BRD) associated with Mannheimia haemolytica, Pasteurella multocida... female dairy cattle 20 months of age or older. Use of florfenicol in this class of cattle may cause milk...

21 CFR 522.955 - Florfenicol.

Science.gov (United States)

2010-04-01

... treatment of bovine respiratory disease (BRD) associated with Mannheimia haemolytica, Pasteurella multocida... cause milk residues. A withdrawal period has not been established in preruminating calves. Do not use in... use. For control of respiratory disease in cattle at high risk of developing BRD associated with...

21 CFR 520.2260b - Sulfamethazine sustained-release boluses.

Science.gov (United States)

2010-04-01

... pneumonia caused or complicated by Pasteurella multocida; as an aid in the treatment of foot rot, mastitis... sulfamethazine-sensitive organisms as follows: bacterial pneumonia and bovine respiratory disease complex... mastitis and acute metritis caused by Streptococcus spp.)1 (iii) Limitations. After 72 hours, all animals...

Fulminant infection by uncommon organisms in animal bite wounds.

Science.gov (United States)

Dutta, J K

1998-10-01

In 1995 and 1996, 215 patients exposed to different species of animals were treated at the Amarnath Polyclinic, Balasore, in India. Among them were two children infected by uncommon organisms, i.e., Capnocytophaga canimorsus and Pasteurella multocida; the patients recovered with appropriate antibiotic therapy.

Fulminant infection by uncommon organisms in animal bite wounds.

OpenAIRE

Dutta, J. K.

1998-01-01

In 1995 and 1996, 215 patients exposed to different species of animals were treated at the Amarnath Polyclinic, Balasore, in India. Among them were two children infected by uncommon organisms, i.e., Capnocytophaga canimorsus and Pasteurella multocida; the patients recovered with appropriate antibiotic therapy.

Management of common animal bites in the emergency centre

African Journals Online (AJOL)

Professor Engelbrecht's current fields of interest are bites, stings and poisonous plants. Correspondence to: ... Cross War Memorial Children's Hospital in. Cape Town ... infections. Wound infection with Pasteurella multocida usually occurs early (within 12 ..... Dog bite prevention: an assessment of child knowledge. J Pediatr ...

(PCR) for the identification of Mycoplasma capricolum subsp.

African Journals Online (AJOL)

ajl yemi

2011-10-07

Oct 7, 2011 ... lactalbumin hydrolysate, 1% MEM, 20% decomplemented horse serum, 5% fresh yeast extract, 1% thallium acetate and 0.4% sodium pyruvate) in a high security laboratory. The DNA of. Pasteurella multocida and Mannheimia haemolytica was maintained in the State Key Laboratory of Veterinary Etiological ...

Forekomst af resistente bakterier og forbrug af antibiotika til hunde

DEFF Research Database (Denmark)

Pedersen, Karl; Pedersen, Kristina; Jensen, Helene

2007-01-01

), Pasteurella multocida (n=25), Bordetella bronchiseptica (n=14), Proteus spp. (n=29), og E. coli (n=449). I undersøgelsen anvendtes data fra VetStat databasen. Størstedelen af de antibiotika, der bruges til hunde er bredspektrede. Penicilliner med udvidet spektrum, cephalosporiner samt sulphonamider...

In vitro screening of methanol plant extracts for their antibacterial activity

International Nuclear Information System (INIS)

Hussain, T.; Arshad, M.; Khan, S.; Sattar, H.

2011-01-01

The purpose of this study was to observe the antibacterial activity of aqueous methanolic extracts of 10 plants against 2-gram negative bacteria (Pasteurella multocida, Escherichia coli) and 3-gram positive bacteria (Bacillus cereus, Staphylococcus aureus, Corynebacterium bovis) by using disc diffusion method. The minimum inhibitory concentration (MIC) was determined by agar well diffusion method and agar dilution method. All the bacteria were susceptible to different plant extracts. Lawsonia inermis, Embellia ribes and Santalum album showed antibacterial activity against all the tested bacteria. The extract of Santalum album showed maximum antibacterial activity of the 10 plant extracts used. Bacillus cereus and Pasteurella multocida were the most sensitive bacteria against most of the plant extracts. It is clear from the results of the present studies that the plant extracts have great potential as antimicrobial compounds against bacteria. However, there is a need of further research to isolate the active ingredients for further pharmacological evaluation. (author)

21 CFR 522.2471 - Tilmicosin.

Science.gov (United States)

2010-04-01

...) Indications for use. For the treatment of bovine respiratory disease (BRD) associated with Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. For the control of respiratory disease in cattle at... dairy cattle 20 months of age or older. Use of this antibiotic in this class of cattle may cause milk...

Gamma-Irradiated Mannheimia (Pasteurella) Haemolytica Identified by rRNA Gene Sequencing as a Potential Vaccine in Mice

International Nuclear Information System (INIS)

Araby, E.

2014-01-01

Pneumonic pasteurellosis is a significant disease in beef production medicine. The most information suggests that this disease is a $700 million dollar per year economic burden in bovine food animal production. The current study was designed to assess the immune efficacy of whole cell killed of M. haemolytica strain from satisfactory cases (infected lung from sheep). The efficacy of gamma- irradiated M. haemolytica vaccine (GIV) was evaluated in mice in comparison to the classical aqueous formalized (AFV) one. The bacteria under study were cultivation on blood agar, purification and genetically identified. Then the bacterial cells were exposed to different doses of gamma radiation (2- 20 kGy) with 2 kGy intervals and the dose response curve of the survivors was plotted and 20 kGy was selected as the dose for the preparation of the vaccine. A total of 30 male mice (two weeks – old) were used for the further experimental investigations. Animals were divided into three equal groups each of 10 animals. The first group (group A) was given GIV . The second group (group B) received AFV. The third group (group C) was injected with sterile saline solution and represents the control. Animals were vaccinated via intraperitoneal (i.p) injection with 1x10 8 CFU per treated mouse. After vaccination, the immuno response was determined by cellular surface antigens-reactive antibodies using a modified protein- electrophoresis procedure. Antibody-antigen hybrids was visualized at molecular weight more than 225 KDa in samples represented M. haemolytica antibodies group (A, B) against both bacterial samples (M. haemolytica and Pasteurella multocida ) , while non-treated bacterial cells in which cells incubated with serum of mice group (C) revealed no hybridization reaction, this results verify that, there is shared cellular surface antigens among the two Pasteurella species. Also, the bacterial distribution with (LD 50 ) 2x10 7 CFU of a live M. heamolytica into vaccinated and non

Pasteurella aerogenes as an Asymptomatic Bacteriuria Agent.

Science.gov (United States)

Alaygut, Demet; Engin, Aynur

2018-02-01

'Asymptomatic bacteriuria' (ASB) is isolation of a specified quantitative count of bacteria in an appropriately collected urine specimen obtained from a person without symptoms or signs referable to urinary infection. Catheterized specimens are less likely to be contaminated compared with voided specimens; therefore, positive cultures of catheterized specimens are more likely to reflect true bladder bacteriuria even with low colony counts. The common pathogens for ASB are Escherichia coli, Klebsiella and Streptococcus spp. Pasteurella spp. was not previously reported as an ASB agent. ASB is important for pregnant women, children, individuals with obstructive uropathy, chronic renal failure and neutropenia, before the urologic procedures and after renal transplantation. Treatment of ASB is required for above situations. We report an 11-year-old-girl with neurogenic bladder who made clean intermittent catheterization and had Pasteurella aerogenes as an ASB agent. © The Author [2017]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Application of Enrofloxacin and Orbifloxacin Disks Approved in Japan for Susceptibility Testing of Representative Veterinary Respiratory Pathogens

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HARADA, Kazuki; USUI, Masaru; ASAI, Tetsuo

2014-01-01

ABSTRACT In this study, susceptibilities of Pasteurella multocida, Mannheimia haemolytica and Actinobacillus pleuropneumoniae to enrofloxacin and orbifloxacin were tested using an agar diffusion method with the commercial disks and a broth microdilution method. Good correlation between the 2 methods for enrofloxacin and orbifloxacin was observed for P. multocida (r = −0.743 and −0.818, respectively), M. haemolytica (r = −0.739 and −0.800, respectively) and A. pleuropneumoniae (r = −0.785 and −0.809, respectively). Based on the Clinical and Laboratory Standards Institute interpretive criteria for enrofloxacin, high-level categorical agreement between the 2 methods was found for P. multocida (97.9%), M. haemolytica (93.8%) and A. pleuropneumoniae (92.0%). Our findings indicate that the tested commercial disks can be applied for susceptibility testing of veterinary respiratory pathogens. PMID:25008965

Phenotypic variability among strains of Pasteurella multocida ...

African Journals Online (AJOL)

STORAGESEVER

2008-05-02

May 2, 2008 ... Available online at http://www.academicjournals.org/AJB. ISSN 1684–5315 ... extended phenotypic characterization methods supported by DNA ... septicaemia African (Obudu) strain (E:2) which are currently employed as ...

9 CFR 113.68 - Pasteurella Haemolytica Vaccine, Bovine.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Pasteurella Haemolytica Vaccine, Bovine. 113.68 Section 113.68 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE... Service. (4) A satisfactory challenge shall be evidenced in the controls by progression of clinical signs...

Avian cholera causes marine bird mortality in the Bering Sea of Alaska

Science.gov (United States)

Bodenstein, Barbara L.; Kimberlee Beckmen,; Gay Sheffield,; Kathy Kuletz,; Van Hemert, Caroline R.; Berlowski-Zier, Brenda M.; Shearn-Bochsler, Valerie I.

2015-01-01

The first known avian cholera outbreak among wild birds in Alaska occurred during November 2013. Liver, intestinal, and splenic necrosis consistent with avian cholera was noted, and Pasteurella multocida serotype 1 was isolated from liver and lung or spleen in Crested Auklets (Aethia cristatella), Thick-billed Murres (Uria lomvia), Common Eider (Somateria mollissima), Northern Fulmars (Fulmarus glacialis), and Glaucous-winged Gulls (Larus glaucescens).

Septicemic pasteurellosis in free-ranging neonatal pronghorn in Oregon

Science.gov (United States)

Dunbar, Michael R.; Wolcott, Mark J.; Rimler, R.B.; Berlowski, Brenda M.

2000-01-01

As part of a study to determine the cause(s) of population decline and low survival of pronghorn (Antilocapra americana) neonates on Hart Mountain National Antelope Refuge (HMNAR), Oregon (USA), 55 of 104 neonates captured during May 1996 and 1997 were necropsied (n = 28, 1996; n = 27, 1997) to determine cause of death. Necropsies were conducted on fawns that died during May, June, or July of each year. The objectives of this study were to report the occurrence and pathology of pasteurellosis in neonates and determine if the isolated strain of Pasteurella multocida was unique. Septicemic pasteurellosis, caused by P. multocida, was diagnosed as the cause of death for two neonates in May and June 1997. Necropsy findings included widely scattered petechial and ecchymotic hemorrhages found over a large portion of the subcutaneous tissue, meninges of the brain, epicardium, skeletal muscle, and serosal surface of the thorasic and abdominal cavities. Histological examination of lung tissues revealed diffuse congestion and edema and moderate to marked multifocal infiltrate of macrophages, neutrophils, and numerous bacteria within many terminal bronchioles and alveoli. Pasteurella multocida serotypes A:3,4, and B:1 were isolated from several tissues including lung, intestinal, thorasic fluid, and heart blood. Each B:1 isolate had DNA restriction endonuclease fingerprint profiles distinct from isolates previously characterized from domestic cattle, swan (Olor spp.), moose (Alces alces), and pronghorn from Montana (USA). This is the first report of pasteurellosis in pronghorn from Oregon and the B:1 isolates appear to be unique in comparison to DNA fingerprint profiles from selected domestic and wild species.

Enzymatic production of human milk oligosaccharides

DEFF Research Database (Denmark)

Guo, Yao

. A recombinant Pasteurella multocida sialyltransferase (EC 2.4.99.-), namely PmST, exhibiting promiscuous trans-sialidase activities was examined. The enzyme catalysed α-2,3- and α-2,6- sialylation of lactose using either 2- O -(p-nitrophenyl)-α- D - N -acetylneuraminic acid or casein glycomacropeptide...... galactooligosaccharides with use of galactooligosaccharides as acceptors. Secondly, we examined the regioselectivity of five designed mutants of PmST catalysing synthesis of 3'- and 6'-sialyllactoses using casein glycomacropeptide and lactose as substrates. The mutants PmST E271F , PmST R313Y and PmST E271F/R313Y...... was almost abolished. The k cat / K m value for PmST P34H catalysing 6'-sialyllactose synthesis using 3'-sialyllactose as donor was 31.2 M -1 s -1 . Moreover, both the wild type enzyme and PmST P34H were capable of catalysing the hydrolysis and transfer of α-2,6 bound sialic acid....

Use of radioactively labelled bacteria in animal experiments. 4

International Nuclear Information System (INIS)

Flossmann, K.D.; Mueller, G.; Heilmann, P.; Finsterbusch, L.; Hubald, J.

1981-01-01

Intratracheal administration of 3 H-, 14 C-, 59 Fe- or 125 I-labelled Pasteurella multocida germs to mice resulted in a more or less differentiated, nuclidedependent distribution of radioactivity in blood, spleen, liver, lung, kidney, and gastrointestinal tract, and was comparable to that following subcutaneous application. The elimination of the antigen from the lungs and other organs could be characterised by an e function, after having reached a certain level of distribution. Some of the antigen was persistent in the lung not less than 14 days. Extremely high activity concentration and persistence was recordable, following the use of 59 Fe complete antigen. Phagocytosis of Pasteurella multocida germs through alveolar macrophages of the lung was secured by autoradiography. Most of the antigen seemed to be discharged from the lungs through the digestive tract. Antigen distribution recorded from immunized and non-immunized mice seemed to suggest that the fate of antigen applied was affected by the kind of immunization. No difference in antigen distribution between non-immunized and subcutaneously immunized animals were provable, following intratracheal antigen application, but is was clearly provable, following intratracheal immunization. Elimination of antigen from the lungs of intratracheally immunized animals was found to occur faster than it did from non-immunized animals. (author)

Isolation of obligate and facultative anaerobic bacteria from feline subcutaneous abscesses.

Science.gov (United States)

Hoshuyama, S; Kanoe, M; Amimoto, A

1996-03-01

A total of 113 specimens collected from purulent skin lesions of household cats was examined bacteriologically. Ninety seven isolates obtained from 74 specimens (65.5%). Of these, 11 specimens (9.7%) contained obligate anaerobes only, 18 specimens (15.9%) yielded both obligate and facultative anaerobes. In the obligate anaerobes detected, genus Fusobacterium was the most frequently observed and F. nucleatum was most common species. Pasteurella multocida was the facultative anaerobe which was most frequently detected.

Experimental infection with different bacterial strains in larvae and juvenile Litopenaeus vannamei reared in Santa Catarina State, Brazil - doi: 10.4025/actascibiolsci.v32i3.5471 Experimental infection with different bacterial strains in larvae and juvenile Litopenaeus vannamei reared in Santa Catarina State, Brazil - doi: 10.4025/actascibiolsci.v32i3.5471

Directory of Open Access Journals (Sweden)

Adolfo Jatoba

2010-09-01

Full Text Available This study evaluated the pathogenic characteristics of bacteria isolated from Litopenaeus vannamei during an outbreak at the Laboratory of Marine Shrimp, UFSC, Santa Catarina State, Brazil. Their virulence potential in larvae and juvenile shrimp and the effects on the total haemocyte count, phenoloxidase activity and serum agglutinate titre were examined after experimental infection. Bacterial strains were isolated from larvae and adult shrimps, identified by the AP120E biochemical system as: two strains of Vibrio alginolyticus, three of Aeromonas salmonicida and one of Pasteurella multocida sp. and Pasteurella sp. All the bacterial strains isolated in this study caused mortality in shrimp. One strain of V. alginolyticus was responsible for 97.3 and 88.7% mortality in larvae and juvenil shrimps, respectively. The shrimp immunological system was influenced by experimental infection with V. alginolyticus. Decrease in the total haemocyte count and increase in the phenoloxidase activity and the serum agglutinate titre (p V. alginolyticus isolated from larvae and juvenile reared marine shrimp.This study evaluated the pathogenic characteristics of bacteria isolated from Litopenaeus vannamei during an outbreak at the Laboratory of Marine Shrimp, UFSC, Santa Catarina State, Brazil. Their virulence potential in larvae and juvenile shrimp and the effects on the total haemocyte count, phenoloxidase activity and serum agglutinate titre were examined after experimental infection. Bacterial strains were isolated from larvae and adult shrimps, identified by the AP120E biochemical system as: two strains of Vibrio alginolyticus, three of Aeromonas salmonicida and one of Pasteurella multocida sp. and Pasteurella sp. All the bacterial strains isolated in this study caused mortality in shrimp. One strain of V. alginolyticus was responsible for 97.3 and 88.7% mortality in larvae and juvenil shrimps, respectively. The shrimp immunological system was influenced by

Antibacterial Activity of the Hydro-Alcoholic Extract of Juglans regia L. Stem Bark on Human Bacterial Infection

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Moori Bakhtiari N.* PhD,

2015-12-01

Full Text Available Aims Bovine mastitis continues to be the most costly disease to the dairy farmers. It dominates in Iran as one of the most prevalent diseases in dairy cattle among the dairy farms. Mastitis treatment with antibiotics leads to the development of antibiotic resistant strains and consumer health problem.This study was performed for the first time to analyze in vitro effects of hydro-alcoholic extract of Juglans regia L. stem bark on 6 mastitis pathogens. Materials & Methods the susceptibility of 6 strains of bacteria (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Streptococcus spp., Pasteurella multocida and Mannheimia haemolytica were analyzed against hydro-alcoholic extract of Juglans regia L. stem bark with minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC methods. Findings Hydro-alcoholic extract did not have antibacterial effects on E. coli and K. pneumoniae. Minimum inhibitory concentration for S. aureus, P. multocida, M. haemolytica and Streptococcus spp. was 62.5mg/ml of hydro-alcoholic extract. There was not any significant response with concentrations below 100mg/disc on S. aureus, Streptococcus species, P. multocida and M. haemolytica. Minimum bactericidal concentration of this extract was 100mg/ml in all isolates. Conclusion Juglans regia L. have some antibacterial effects on S. aureus, P. multocida, M. haemolytica and Streptococcus species.

Birds in Human Modified Environments and Bird Damage Control: Social, Economic, and Health Implications

Science.gov (United States)

1989-12-01

Paratyphoid (Salmonella typhimurium) x x x + + .+ + + . + + + + Pasteurellasis (Fowl cholera ) (Pasteurella multocida) x x...enteritis (Clostridlum colinum) x 0 0 Vibriosis ( Vibrio fetu) x 30 Table 4 (ContWd Carriers r. .14 0 C c to to z ca -W V 0 4 w .,.4 ". Ca 0 3d ca DI .C...endemic vector of EEE in North America (Reeves et al. 1958, Howard and Wallis 1974). This species breeds in freshwater swamps from the Gulf of Mexico

A longitudinal study of serological patterns of respiratory infections in nine infected Danish swine herds

DEFF Research Database (Denmark)

Andreasen, Margit; Nielsen, Jens; Bækbo, Poul

2000-01-01

Sixteen litters of seven pigs from each of nine Danish farrow-to-finish herds were followed to investigate the serological patterns caused by natural infection with Mycoplasma hyponeumoniae, Pasteurella multocida toxin and Actinobacillus pleuroneumoniae serotypes 2, 5-7, 12. In seven of the herds......, pigs were followed as two separate cohorts started 4 weeks apart, and in two herds only one cohort was followed. A total of 999 pigs were included in the study. The pigs were blood sampled at weaning and subsequently every fourth week until slaughter. All pigs were examined for antibodies against M....... hyopneumoniae (enzyme-linked immunosorbent assay), P. multocida toxin (enzyme-linked immunosorbent assay) and A. pleuropneumoniae serotypes 2, 5-7, 12 (complement-fixation tests). The most-common pattern (28%) of seroconversion was that of pigs first seroconverting to A. pleuropneumoniae serotype 2, followed...

Occurrence of antimicrobial resistance in bacteria from diagnostic samples from dogs

DEFF Research Database (Denmark)

Pedersen, Karl; Pedersen, Kristina; Jensen, Helene

2007-01-01

Pseudomonas aeruginosa, 25 Pasteurella multocida, 29 Proteus spp. and 449 Escherichia coli isolates from clinical submissions from dogs were determined by a broth-dilution method for determination of minimal inhibitory concentration. Data for consumption of antimicrobials were retrieved from Vet....... intermedius and Proteus isolates. Conclusions: This investigation provided data on occurrence of antimicrobial resistance in important pathogenic bacteria from dogs, which may be useful for the small animal practitioner. Resistance was low to the compounds that were most often used, but unfortunately...

Avian cholera in waterfowl: the role of lesser snow and Ross's geese as carriers of avian cholera in the Playa Lakes region

Science.gov (United States)

Samuel, M.D.; Shadduck, D.J.; Goldberg, Diana R.; Johnson, W.P.

2005-01-01

We collected samples from apparently healthy geese in the Playa Lakes Region (USA) during the winters of 2000a??01 and 2001a??02 to determine whether carriers of Pasteurella multocida, the bacterium that causes avian cholera, were present in wild populations. With the use of methods developed in laboratory challenge trials (Samuel et al., 2003a) and a serotype-specific polymerase chain reaction method for identification of P. multocida serotype 1, we found that a small proportion of 322 wild birds (cholera infection. Our results confirm the hypothesis that wild waterfowl are carriers of avian cholera and add support for the hypothesis that wild birds are a reservoir for this disease. In concert with other research, this work indicates that enzootic infection with avian cholera occurs in lesser snow goose (Chen caerulescens caerulescens) populations throughout their annual cycle. Although fewer Rossa??s geese (Chen rossii) were sampled, we also found these birds were carriers of P. multocida. Even in the absence of disease outbreaks, serologic evidence indicates that chronic disease transmission and recent infection are apparently occurring year-round in these highly gregarious birds and that a small portion of these populations are potential carriers with active infection.

An Investigation of the Pathology and Pathogens Associated with Porcine Respiratory Disease Complex in Denmark

DEFF Research Database (Denmark)

Hansen, Mette Sif; Pors, S. E.; Jensen, H. E.

2010-01-01

), porcine reproductive and respiratory syndrome virus (both European and US type), porcine circovirus type 2 (PCV2), porcine respiratory coronavirus, porcine cytomegalovirus, Mycoplasma hyopneumoniae and Mycoplasma hyorhinis. All cases had cranioventral lobular bronchopneumonia consistent with PRDC....... There was a broad range of microscopical lesions and the cases were characterized as acute (n=10), subacute (n=24) or chronic (n=114) bronchopneumonia. Five bacterial species, five viruses and two Mycoplasma spp. were detected in different combinations. PCV2, M. hyopneumoniae, M. hyorhinis and Pasteurella multocida...

Fatal pneumonia of bighorn sheep following association with domestic sheep.

Science.gov (United States)

Foreyt, W J; Jessup, D A

1982-04-01

During 1979-1980 acute fibrinopurulent bronchopneumonia resulted in high mortality or total loss of herds of bighorn sheep (Ovis canadensis) in California and Washington. Contact with domestic sheep occurred shortly before the onset of disease in each case. Circumstantial evidence indicated that the apparently healthy domestic sheep transmitted pathogenic bacteria to the bighorns, resulting in mortality. Pasteurella multocida and Corynebacterium pyogenes were isolated from pulmonary tissue of dead bighorns. The presence of domestic sheep may have been an important stress which initiated or compounded the disease.

Biased distribution of DNA uptake sequences towards genome maintenance genes

DEFF Research Database (Denmark)

Davidsen, T.; Rodland, E.A.; Lagesen, K.

2004-01-01

Repeated sequence signatures are characteristic features of all genomic DNA. We have made a rigorous search for repeat genomic sequences in the human pathogens Neisseria meningitidis, Neisseria gonorrhoeae and Haemophilus influenzae and found that by far the most frequent 9-10mers residing within...... in these organisms. Pasteurella multocida also displayed high frequencies of a putative DUS identical to that previously identified in H. influenzae and with a skewed distribution towards genome maintenance genes, indicating that this bacterium might be transformation competent under certain conditions....

Antimicrobial susceptibility monitoring of respiratory tract pathogens isolated from diseased cattle and pigs across Europe: the VetPath study.

Science.gov (United States)

de Jong, Anno; Thomas, Valérie; Simjee, Shabbir; Moyaert, Hilde; El Garch, Farid; Maher, Kirsty; Morrissey, Ian; Butty, Pascal; Klein, Ulrich; Marion, Hervé; Rigaut, Delphine; Vallé, Michel

2014-08-06

VetPath is an ongoing pan-European antibiotic susceptibility monitoring programme collecting pathogens from diseased antimicrobial non-treated cattle, pigs and poultry. In the current study, 1001 isolates from cattle and pig respiratory tract infections were tested for their antimicrobial susceptibilities. Non-replicate lung samples or nasopharyngeal/nasal swabs were collected from animals with acute clinical signs in 11 countries during 2002-2006. Pasteurella multocida and Mannheimia haemolytica from cattle and P. multocida, Actinobacillus pleuropneumoniae and Streptococcus suis from pigs were isolated by standard methods. S. suis was also isolated from meningitis cases. MICs of 16 antibiotics were assessed centrally by broth microdilution following CLSI recommendations. Results were interpreted using CLSI breakpoints where available. P. multocida (231) and M. haemolytica (138) isolates were all susceptible to amoxicillin/clavulanic acid, ceftiofur, enrofloxacin and trimethoprim/sulfamethoxazole. Resistance to florfenicol and spectinomycin was 0.4% and 3.5% in P. multocida, respectively, and absent in M. haemolytica isolates. Tetracycline resistance was 5.7% and 14.6% for P. multocida and M. haemolytica. In pigs, 230 P. multocida, 220 A. pleuropneumoniae and 182 S. suis isolates were recovered. Resistance to amoxicillin/clavulanic acid, ceftiofur, enrofloxacin, florfenicol, tiamulin and tilmicosin was absent or <1%. Trimethoprim/sulfamethoxazole resistance was 3-6% and tetracycline resistance varied from 14.7% in A. pleuropneumoniae to 81.8% in S. suis. In conclusion, low resistance to antibiotics with defined clinical breakpoints, except for tetracycline, was observed among the major respiratory tract pathogens recovered from cattle and pigs. Since for approximately half of the antibiotics in this panel no CLSI-defined breakpoints were available, setting of the missing veterinary breakpoints is important. Copyright © 2014 Elsevier B.V. All rights reserved.

Microbiological and serological monitoring in hooded crow (Corvus corone cornix in the Region Lombardia, Italy

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Guido Grilli

2010-01-01

Full Text Available The health status of 276 hooded crows (Corvus corone cornix from various provinces of Lombardy was monitored for three years. Bacteriological examination detected E. coli (76%, Campylobacter jejuni (17%, Salmonella typhimurium (11.6%, Yersinia spp. (6.5%, Clamydophila abortus and C. psittaci (2.6%; from six birds showing severe prostration Pasteurella multocida was isolated. Virological and serological tests were negative for Avian Influenza virus (AIV, West Nile virus (WNV and only three samples were positive for Newcastle disease virus (NDV but only at serology (titre 1:16.

Development of pneumonia in desert bighorn sheep after exposure to a flock of exotic wild and domestic sheep.

Science.gov (United States)

Callan, R J; Bunch, T D; Workman, G W; Mock, R E

1991-03-15

From 1986 to 1989, 5 desert bighorn sheep (3 Ovis canadensis mexicana and 2 O c nelsoni), ranging in age from 2 to 3 years, were exposed to a flock of exotic wild and domestic sheep to potentially achieve naturally acquired pneumonia. Pasteurella multocida was isolated from nasal samples from 4 of 6 sheep randomly sampled from the flock. Bighorn sheep were exposed individually and each exposure period was a trial. Treatment before and after exposure varied and included combinations of alpha interferon, antibiotics, anti-inflammatory drugs, and vaccines. Treatments were chosen on the basis of recommendations of others for treating pneumonia in desert bighorn sheep as well as our own experience in sheep and cattle. Regardless of treatment used, bighorn sheep in trials 1 to 4 developed signs of pneumonia within 10 to 14 days of exposure. Bighorn sheep in trials 1 to 3 died within 11 to 17 days of initial exposure. In trial 4, the bighorn sheep was isolated from the carrier sheep for treatment of pneumonia on day 14 and died on day 30. Pasteurella multocida was isolated from lung tissue in 3 of the 4 bighorn sheep. On the basis of results of trials 1 to 4, a more in depth clinical study was conducted in trial 5. Nasal and blood specimens were collected prior to and during trial 5 for bacteriologic culturing and serologic testing for bovine viral diarrhea virus, infectious bovine rhinotracheitis, parainfluenza-3 virus, and respiratory syncytial virus.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pasteurella] caballi infection not limited to horses - a closer look at taxon 42 of Bisgaard

DEFF Research Database (Denmark)

Christensen, Henrik; Hommez, J.; Olsen, John Elmerdahl

2006-01-01

Aim To investigate if taxon 42 of Bisgaard isolated from pigs represents genuine [Pasteurella] caballi which has previously only been isolated from horses. Methods and Results A total of 15 field isolates from horses and pigs from 5 different countries representing three continents were to subjec...

Pasteurella testudinis associated with respiratory disease and septicaemia in leopard (Geochelone pardalis and other tortoises in South Africa

Directory of Open Access Journals (Sweden)

M.M. Henton

2003-07-01

Full Text Available The first recorded isolates of Pasteurella testudinis from South African tortoises kept in captivity is presented. P. testudinis was found in association with respiratory disease in affected animals.

RESPIRATORY SYNDROME: A MAJOR THREAT TO THE LIVESTOCK FARMERS AND ITS ECONOMIC IMPACT

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A. B. ZAHUR, U. FAROOQ, M. HUSSAIN1, S. H. HASHMI2 AND R. MUNEER

2007-10-01

Full Text Available Epidemiology of a respiratory syndrome was studied at Landhi Dairy Colony (LDC, Karachi, Pakistan and its economic impact was estimated. Among 5889 buffaloes examined, 2.3% animals were suffering from this syndrome. From some of the sick animals, Pasteurella multocida, the causative agent of haemorrhagic septicaemia, was isolated. In the present study, an average loss of Rs. 0.2 million per farm was calculated and the extrapolated values for 0.2 and 0.8 million animals present in LDC and other dairy colonies in Karachi were Rs. 225.6 and Rs. 1128.1 million, respectively.

Effects of Enrofloxacin on Porcine Phagocytic Function

Science.gov (United States)

Schoevers, E. J.; van Leengoed, L. A. M. G.; Verheijden, J. H. M.; Niewold, T. A.

1999-01-01

The interaction between enrofloxacin and porcine phagocytes was studied with clinically relevant concentrations of enrofloxacin. Enrofloxacin accumulated in phagocytes, with cellular concentration/extracellular concentration ratios of 9 for polymorphonuclear leukocytes (PMNs) and 5 for alveolar macrophages (AMs). Cells with accumulated enrofloxacin brought into enrofloxacin-free medium released approximately 80% (AMs) to 90% (PMNs) of their enrofloxacin within the first 10 min, after which no further release was seen. Enrofloxacin affected neither the viability of PMNs and AMs nor the chemotaxis of PMNs at concentrations ranging from 0 to 10 μg/ml. Enrofloxacin (0.5 μg/ml) did not alter the capability of PMNs and AMs to phagocytize fluorescent microparticles or Actinobacillus pleuropneumoniae, Pasteurella multocida, and Staphylococcus aureus. Significant differences in intracellular killing were seen with enrofloxacin at 5× the MIC compared with that for controls not treated with enrofloxacin. PMNs killed all S. aureus isolates in 3 h with or without enrofloxacin. Intracellular S. aureus isolates in AMs were less susceptible than extracellular S. aureus isolates to the bactericidal effect of enrofloxacin. P. multocida was not phagocytosed by PMNs. AMs did not kill P. multocida, and similar intra- and extracellular reductions of P. multocida isolates by enrofloxacin were found. Intraphagocytic killing of A. pleuropneumoniae was significantly enhanced by enrofloxacin at 5× the MIC in both PMNs and AMs. AMs are very susceptible to the A. pleuropneumoniae cytotoxin. This suggests that in serologically naive pigs the enhancing effect of enrofloxacin on the bactericidal action of PMNs may have clinical relevance. PMID:10471554

Phenotypic and genotypic characterization of Mannheimia (Pasteurella) haemolytica-like strains isolated from diseased animals in Denmark

DEFF Research Database (Denmark)

Angen, Øystein; Ahrens, Peter; Bisgaard, M.

2002-01-01

Trehalose-negative strains of the Pasteurella haemolytica complex have recently been transferred to a new genus, Mannheimia. This genus presently consists of five named species: M. haemolytica, M. glucosida, M. granulomatis, M. ruminalis and M. varigena. The purpose of this study was to investigate...

Clonal outbreaks of [ Pasteurella] pneumotropica biovar Heyl in two mouse colonies

DEFF Research Database (Denmark)

Adhikary, Sadhana; Bisgaard, Magne; Dagnæs-Hansen, Frederik

2017-01-01

The aim of this study was to document the pathogenic role of biovar Heyl of [Pasteurella] pneumotropica in mouse colonies. Fifty-three isolates associated with mastitis and orbital, cutaneous and vaginal abscesses as well as isolates from the nose and vagina of healthy mice were investigated...... strains with the same rpoB sequence type, as shown by the PFGE profiles. The investigation documented that members of biovar Heyl of [P.] pneumotropica caused disease outbreaks in mouse colonies since the clonality indicated a primary role of [P.] pneumotropica biovar Heyl in the infections observed....

Outbreak of Pasteurella pneumotropica in a closed colony of STOCK-Cd28(tm1Mak) mice

DEFF Research Database (Denmark)

Artwohl, J.E.; Flynn, J.C.; Bunte, R.M.

2000-01-01

Fifteen mice with Pasteurella pneumotropica orbital abscesses were noted in mice that were homozygous for a targeted Cd28 gene mutation. Only one mouse heterozygous for the Cd28 mutation was affected. According to phenotypic reactions and 16S rDNA sequencing, the isolates were most similar to bio...

Standard PK/PD concepts can be applied to determine a dosage regimen for a macrolide: the case of tulathromycin in the calf.

Science.gov (United States)

Toutain, P-L; Potter, T; Pelligand, L; Lacroix, M; Illambas, J; Lees, P

2017-01-01

The pharmacokinetic (PK) profile of tulathromycin, administered to calves subcutaneously at the dosage of 2.5 mg/kg, was established in serum, inflamed (exudate), and noninflamed (transudate) fluids in a tissue cage model. The PK profile of tulathromycin was also established in pneumonic calves. For Mannheimia haemolytica and Pasteurella multocida, tulathromycin minimum inhibitory concentrations (MIC) were approximately 50 times lower in calf serum than in Mueller-Hinton broth. The breakpoint value of the PK/pharmacodynamic (PD) index (AUC (0-24 h) /MIC) to achieve a bactericidal effect was estimated from in vitro time-kill studies to be approximately 24 h for M. haemolytica and P. multocida. A population model was developed from healthy and pneumonic calves and, using Monte Carlo simulations, PK/PD cutoffs required for the development of antimicrobial susceptibility testing (AST) were determined. The population distributions of tulathromycin doses were established by Monte Carlo computation (MCC). The computation predicted a target attainment rate (TAR) for a tulathromycin dosage of 2.5 mg/kg of 66% for M. haemolytica and 87% for P. multocida. The findings indicate that free tulathromycin concentrations in serum suffice to explain the efficacy of single-dose tulathromycin in clinical use, and that a dosage regimen can be computed for tulathromycin using classical PK/PD concepts. © 2016 John Wiley & Sons Ltd.

Dicty_cDB: AFK338 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available AF (Link to library) AFK338 (Link to dictyBase) - - - - AFK338P (Link to Original s...ite) AFK338F 659 AFK338Z 221 AFK338P 880 - - Show AFK338 Library AF (Link to library) Clone ID AFK338 (Link to dic...01175_2502( CP001175 |pid:none) Listeria monocytogenes HCC23, c... 40 0.099 AY714838_16( AY714838 |pid:none) Unculture...A sequence. 44 3.0 1 AE006080 |AE006080.1 Pasteurella multocida PM70 section 47 o... 0.003 BX294148_242( BX294148 |pid:none) Rhodopirellula baltica SH 1 comp... 44 0.005 CP000910_1528( CP00091

Experimental contact transmission of Pasteurella haemolytica from clinically normal domestic sheep causing pneumonia in Rocky Mountain bighorn sheep.

Science.gov (United States)

Onderka, D K; Wishart, W D

1988-10-01

Two Rocky Mountain bighorn lambs (Ovis canadensis canadensis) were held in captivity for 120 days before being housed with two domestic sheep. The lambs were clinically normal and had no Pasteurella spp. on nasal swab cultures. The domestic sheep were known to carry Pasteurella haemolytica biotype A in the nasal passages. After being in close contact for 19 days. P. haemolytica biotype A was cultured from nasal swabs of one of the bighorn lambs. By 26 days, both bighorn sheep developed coughs, were anorectic and became lethargic and nasal swabs yielded P. haemolytica biotype T, serotype 10. Twenty-nine days after contact, the lambs were necropsied and found to have extensive fibrinous bronchopneumonia. From affected tissues pure cultures of beta-hemolytic P. haemolytica biotype T, serotype 10 were grown. Both domestic sheep remained clinically normal and had no gross or microscopic lesions, but they carried the same P. haemolytica serotype in their tonsils. Behavioural observations gave no indication of stress in the bighorn lambs.

Fatal pneumonia following inoculation of healthy bighorn sheep with Pasteurella haemolytica from healthy domestic sheep.

Science.gov (United States)

Foreyt, W J; Snipes, K P; Kasten, R W

1994-04-01

In a series of three experiments, isolates of Pasteurella haemolytica biotype A, serotype 2, ribotype reference WSU-1, from healthy domestic sheep, were inoculated intratracheally into eight bighorn sheep (Ovis canadensis canadensis) and seven domestic sheep with doses of bacteria ranging from 5.3 x 10(8) to 8.6 x 10(11) colony forming units. Seven of eight inoculated bighorn sheep died from acute pneumonia within 48 hr of inoculation, whereas all seven domestic sheep inoculated with comparable or greater doses of bacteria remained healthy. One contact control bighorn sheep also died 6 days after its penmates received P. haemolytica. Three other noncontact control bighorn sheep remained healthy during the experiments. Pasteurella haemolytica biotype A, serotype 2, ribotype reference WSU-1 in the inocula was recovered from one or more tissues from all bighorns that died; whereas, it was not detected in any bighorn sheep before inoculation. Three different ribotypes of P. haemolytica A2 were recovered from bighorn sheep; however, only the ribotype reference WSU-1 in the domestic sheep-origin inoculum was recovered from all dead bighorn sheep, and was not recovered from bighorn sheep that survived the experiments. Thus, a relatively nonpathogenic and common isolate of P. haemolytica from healthy domestic sheep was lethal in bighorn sheep under experimental conditions.

Comparative studies on [Pasteurella] testudinis and [P.] testudinis-like bacteria and proposal of Chelonobacter oris gen. nov., sp. nov. as a new member of the family Pasteurellaceae

DEFF Research Database (Denmark)

Gregersen, Rikke Heidemann; Neubauer, Claudia; Christensen, Henrik

2009-01-01

Abstract A collection of 12 strains isolated from diseased tortoises tentatively identified as [Pasteurella] testudinis-like based on phenotypical characters were compared with three reference strains of [Pasteurella] testudinis. All strains could be separated from the reference strains with resp...

Mycoplasma ovipneumoniae - A Primary Cause of Severe Pneumonia Epizootics in the Norwegian Muskox (Ovibos moschatus) Population

Science.gov (United States)

Handeland, Kjell; Tengs, Torstein; Kokotovic, Branko; Vikøren, Turid; Ayling, Roger D.; Bergsjø, Bjarne; Sigurðardóttir, Ólöf G.; Bretten, Tord

2014-01-01

The Norwegian muskox (Ovibos moschatus) population lives on the high mountain plateau of Dovre and originates from animals introduced from Greenland. In the late summers of 2006 and 2012, severe outbreaks of pneumonia with mortality rates of 25-30% occurred. During the 2012 epidemic high quality samples from culled sick animals were obtained for microbiological and pathological examinations. High throughput sequencing (pyrosequencing) of pneumonic lung tissue revealed high concentrations of Mycoplasma ovipneumoniae in all six animals examined by this method and Pasteurella multocida subsp. multocida in four animals, whereas no virus sequences could be identified. Mycoplasma ovipneumoniae and P. multocida multocida were also isolated by culture. Using real time PCR on lung swabs, M. ovipneumoniae was detected in all of the 19 pneumonic lungs examined. Gross pathological examination revealed heavy consolidations primarily in the cranial parts of the lungs and it also identified one case of otitis media. Histologically, lung lesions were characterized as acute to subacute mixed exudative and moderately proliferative bronchoalveolar pneumonia. Immunohistochemical (IHC) examination revealed high load of M. ovipneumoniae antigens within lung lesions, with particularly intensive staining in the neutrophils. Similar IHC finding were observed in archived lung tissue blocks from animals examined during the 2006 epidemic. An M. ovipneumoniae specific ELISA was applied on bio-banked muskox sera from stray muskoxen killed in the period 2004–2013 and sick muskoxen culled, as well as sera from wild reindeer (Rangifer tarandus tarandus) on Dovre and muskoxen from Greenland. Serology and mycoplasma culturing was also carried out on sheep that had been on pasture in the muskox area during the outbreak in 2012. Our findings indicated separate introductions of M. ovipneumoniae infection in 2006 and 2012 from infected co-grazing sheep. Salt licks shared by the two species were a

Mycoplasma ovipneumoniae--a primary cause of severe pneumonia epizootics in the Norwegian Muskox (Ovibos moschatus population.

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Kjell Handeland

Full Text Available The Norwegian muskox (Ovibos moschatus population lives on the high mountain plateau of Dovre and originates from animals introduced from Greenland. In the late summers of 2006 and 2012, severe outbreaks of pneumonia with mortality rates of 25-30% occurred. During the 2012 epidemic high quality samples from culled sick animals were obtained for microbiological and pathological examinations. High throughput sequencing (pyrosequencing of pneumonic lung tissue revealed high concentrations of Mycoplasma ovipneumoniae in all six animals examined by this method and Pasteurella multocida subsp. multocida in four animals, whereas no virus sequences could be identified. Mycoplasma ovipneumoniae and P. multocida multocida were also isolated by culture. Using real time PCR on lung swabs, M. ovipneumoniae was detected in all of the 19 pneumonic lungs examined. Gross pathological examination revealed heavy consolidations primarily in the cranial parts of the lungs and it also identified one case of otitis media. Histologically, lung lesions were characterized as acute to subacute mixed exudative and moderately proliferative bronchoalveolar pneumonia. Immunohistochemical (IHC examination revealed high load of M. ovipneumoniae antigens within lung lesions, with particularly intensive staining in the neutrophils. Similar IHC finding were observed in archived lung tissue blocks from animals examined during the 2006 epidemic. An M. ovipneumoniae specific ELISA was applied on bio-banked muskox sera from stray muskoxen killed in the period 2004-2013 and sick muskoxen culled, as well as sera from wild reindeer (Rangifer tarandus tarandus on Dovre and muskoxen from Greenland. Serology and mycoplasma culturing was also carried out on sheep that had been on pasture in the muskox area during the outbreak in 2012. Our findings indicated separate introductions of M. ovipneumoniae infection in 2006 and 2012 from infected co-grazing sheep. Salt licks shared by the two

Comparison of the diagnostic performance of bacterial culture of nasopharyngeal swab and bronchoalveolar lavage fluid samples obtained from calves with bovine respiratory disease.

Science.gov (United States)

Capik, Sarah F; White, Brad J; Lubbers, Brian V; Apley, Michael D; DeDonder, Keith D; Larson, Robert L; Harhay, Greg P; Chitko-McKown, Carol G; Harhay, Dayna M; Kalbfleisch, Ted S; Schuller, Gennie; Clawson, Michael L

2017-03-01

OBJECTIVE To compare predictive values, extent of agreement, and gamithromycin susceptibility between bacterial culture results of nasopharyngeal swab (NPS) and bronchoalveolar lavage fluid (BALF) samples obtained from calves with bovine respiratory disease (BRD). ANIMALS 28 beef calves with clinical BRD. PROCEDURES Pooled bilateral NPS samples and BALF samples were obtained for bacterial culture from calves immediately before and at various times during the 5 days after gamithromycin (6 mg/kg, SC, once) administration. For each culture-positive sample, up to 12 Mannheimia haemolytica, 6 Pasteurella multocida, and 6 Histophilus somni colonies underwent gamithromycin susceptibility testing. Whole-genome sequencing was performed on all M haemolytica isolates. For paired NPS and BALF samples collected 5 days after gamithromycin administration, the positive and negative predictive values for culture results of NPS samples relative to those of BALF samples and the extent of agreement between the sampling methods were determined. RESULTS Positive and negative predictive values of NPS samples were 67% and 100% for M haemolytica, 75% and 100% for P multocida, and 100% and 96% for H somni. Extent of agreement between results for NPS and BALF samples was substantial for M haemolytica (κ, 0.71) and H somni (κ, 0.78) and almost perfect for P multocida (κ, 0.81). Gamithromycin susceptibility varied within the same sample and between paired NPS and BALF samples. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated culture results of NPS and BALF samples from calves with BRD should be interpreted cautiously considering disease prevalence within the population, sample collection relative to antimicrobial administration, and limitations of diagnostic testing methods.

Experimental infection with different bacterial strains in larvae and juvenile Litopenaeus vannamei reared in Santa Catarina State, Brazil = Infecção experimental em larvas e juvenis de Litopaenaeus vannamei cultivados no Estado de Santa Catarina, Brasil

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Celso Carlos Buglione

2010-07-01

Full Text Available This study evaluated the pathogenic characteristics of bacteria isolated from Litopenaeus vannamei during an outbreak at the Laboratory of Marine Shrimp, UFSC, Santa Catarina State, Brazil. Their virulence potential in larvae and juvenile shrimp and theeffects on the total haemocyte count, phenoloxidase activity and serum agglutinate titre were examined after experimental infection. Bacterial strains were isolated from larvae and adult shrimps, identified by the AP120E biochemical system as: two strains of Vibrioalginolyticus, three of Aeromonas salmonicida and one of Pasteurella multocida sp. and Pasteurella sp. All the bacterial strains isolated in this study caused mortality in shrimp. One strain of V. alginolyticus was responsible for 97.3 and 88.7% mortality in larvae and juvenil shrimps, respectively. The shrimp immunological system was influenced by experimental infection with V. alginolyticus. Decrease in the total haemocyte count and increase in the phenoloxidase activity and the serum agglutinate titre (p Este estudo avaliou as características patogênicas de cepas de bactérias isoladas de Litopenaeus vannamei durante surto de mortalidade no Laboratório de Camarões Marinhos, UFSC, Estado de Santa Catarina, Brasil. Seu potencial de virulência em larvas e juvenis de camarão marinho e os efeitos sobre a contagem total de hemócito, atividade de fenoloxidase e título aglutinante do soro foramavaliados após infecção experimental. As cepas bacterianas foram isoladas de larvas e de camarões adultos e identificadas bioquimicamente pelo sistema API20E como: duas cepas de Vibrio alginolyticus, três de Aeromonas salmonicida e uma de Pasteurella sp. e P. multocida. Todas as cepas isoladas provocaram mortalidade em L. vannamei, e uma de V. alginolyticus resultou em mortalidade de 97,3 e 88,7% para larvas e juvenis de camarões, respectivamente. O sistema imunológico dos camarões juvenis sofreu influência da infecção experimental

Short communication: Interaction of the isomers carvacrol and thymol with the antibiotics doxycycline and tilmicosin: In vitro effects against pathogenic bacteria commonly found in the respiratory tract of calves.

Science.gov (United States)

Kissels, W; Wu, X; Santos, R R

2017-02-01

Bovine respiratory disease is the major problem faced by cattle, specially calves, leading to reduced animal performance and increased mortality, consequently causing important economic losses. Hence, calves must be submitted to antibiotic therapy to counteract this infection usually initiated by the combination of environmental stress factors and viral infection, altering the animal's defense mechanism, and thus allowing lung colonization by the opportunistic bacteria Mannheimia haemolytica and Pasteurella multocida. Essential oils appear to be candidates to replace antibiotics or to act as antibiotic adjuvants due to their antimicrobial properties. In the present study, we aimed to evaluate the 4 essential oil components carvacrol, thymol, trans-anethole, and 1,8 cineole as antibacterial agents or as adjuvants for the antibiotics doxycycline and tilmicosin against M. haemolytica and P. multocida. Bacteria were cultured according to standard protocols, followed by the determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration. A checkerboard assay was applied to detect possible interactions between components, between antibiotics, and between components and antibiotics. Doxycycline at 0.25 and 0.125 μg/mL inhibited the growth of P. multocida and M. haemolytica, respectively, whereas tilmicosin MIC values were 1.0 and 4.0 μg/mL for P. multocida and M. haemolytica, respectively. Carvacrol MIC values were 2.5 and 1.25 mM for P. multocida and M. haemolytica, respectively, whereas thymol MIC values were 1.25 and 0.625 mM for P. multocida and M. haemolytica, respectively. Trans-anethole and 1,8 cineole did not present any antibacterial effect even at 40 mM against the investigated pathogens. All minimum bactericidal concentration values were the same as MIC, except when thymol was tested against M. haemolytica, being twice the MIC data (i.e., 1.25 mM thymol). Based on fractional inhibitory concentration checkerboard assay, no

Investigation of genome sequences within the family Pasteurellaceae

DEFF Research Database (Denmark)

Angen, Øystein; Ussery, David

Introduction The bacterial genome sequences are now available for an increasing number of strains within the family Pasteurellaceae. At present, 24 Pasteurellaceae genomes are publicly available through internet databases, and another 40 genomes are being sequenced. This investigation will describe...... the core genome for both the family Pasteurellaceae and for the species Haemophilus influenzae. Methods Twenty genome sequences from the following species were included: Haemophilus influenzae (11 strains), Haemophilus ducreyi (1 strain), Histophilus somni (2 strains), Haemophilus parasuis (1 strain......), Actinobacillus pleuropneumoniae (2 strains), Actinobacillus succinogenes (1 strain), Mannheimia succiniciproducens (1 strain), and Pasteurella multocida (1 strain). The predicted proteins for each genome were BLASTed against each other, and a set of conserved core gene families was determined as described...

Aspects relating to use of radioactively labelled bacteria in animal experiments. 7

International Nuclear Information System (INIS)

Heilmann, P.; Flossmann, K.D.; Mueller, G.; Finsterbusch, L.

1983-01-01

Two different types of aerosol dispensers were used in an aerosol compartment to apply 59 Fe-labelled bacteria (Pasteurella multocida) to SPE Mini-LEWE piglets as well as to conventionally raised piglets and calves. Germ intake was verified by detection of radioactivity in the lungs. Antigen deposition on each lung amounted to 2-3 . 10 8 in mini-piglets, 6-8 . 10 8 in ordinary piglets, and 2 . 10 9 in conventionally raised calves, as determined by SAG-1, a Soviet model of aerosol dispenser. More or less equally high concentrations of aerosol particles were retained in the pulmonary lobes, independent of the animal species used. Antigen intake could not be influenced by addition of skim milk or by restriction of germ suspensions. (author)

Rapport for Center for Vildtsundhed 1. halvår 2012

DEFF Research Database (Denmark)

Chriél, Mariann; Enemark, Heidi L.; Therkildsen, Ole Roland

for vurderingen af parasitbelastningen hos raske ederfugle. Redemateriale til undersøgelse af Pasteurella multocida, der forårsager udbrud af fjerkrækolera, fortsættes i et specialestudie af de dyrkbare bakterier. Med henblik på kortlægning af rævens dværgbændelorm (Echinococcus multilocularis) hos mårhund og ræv...... Danmark siden 2000, og det er første gang bændelormen er påvist i jyske ræve. Echinococcus multilocularis kan smitte til mennesker, hvor de i larvestadiet angriber leveren, hvilket kan have fatale følger, så det er vigtigt, at folk er opmærksomme på risikoen og tager deres forbehold. Mennesker smittes...

Toll-like receptor 4-positive macrophages protect mice from Pasteurella pneumotropica-induced pneumonia

Science.gov (United States)

Hart, Marcia L.; Mosier, Derek A.; Chapes, Stephen K.

2003-01-01

This study investigates Toll-like receptor 4 (TLR4)-positive macrophages in early recognition and clearance of pulmonary bacteria. TLR4 is a trans-membrane receptor that is the primary recognition molecule for lipopolysaccharide of gram-negative bacteria. The TLR4(Lps-del) mouse strains C57BL10/ScN (B10) and STOCK Abb(tm1) TLR4(Lps-del) Slc11a1(s)(B10 x C2D) are susceptible to pulmonary infections and develop pneumonia when naturally or experimentally infected by the opportunistic bacterium Pasteurella pneumotropica. Since these mice have the TLR4(Lps-del) genotype, we hypothesized that reconstitution of mice with TLR4-positive macrophages would provide resistance to this bacterium. A cultured macrophage cell line (C2D macrophages) and bone marrow cells from C2D mice were adoptively transferred to B10 and B10 x C2D mice by intraperitoneal injection. C2D macrophages increased B10 and B10 x C2D mouse resistance to P. pneumotropica. In C2D-recipient mice there was earlier transcription of tumor necrosis factor alpha and chemokines JE and macrophage inflammatory protein 2 (MIP-2) in the lungs of B10 and B10 x C2D mice, and there was earlier transcription of KC and MIP-1alpha in B10 x C2D mice. In addition, the course of inflammation following experimental Pasteurella challenge was altered in C2D recipients. C2D macrophages also protected B10 x C2D mice, which lack CD4(+) T cells. These data indicate that macrophages are critical for pulmonary immunity and can provide host resistance to P. pneumotropica. This study indicates that TLR4-positive macrophages are important for early recognition and clearance of pulmonary bacterial infections.

Pathological and molecular based study of pneumonic pasteurellosis in cattle and buffalo (bubalus bubalis)

International Nuclear Information System (INIS)

Hussain, R.

2014-01-01

In present study the clinico-pathological findings were recorded in naturally infected cattle and buffaloes due to pasteurella multocida during an outbreak at different livestock herds. There was no significant difference in mortality among various groups of buffaloes (p>0.78) and cattle (p>0.49). The infected animals showed clinical signs of moderate to acute anorexia, salivation, fever, depression, dysponea, submandibular edema, mucopurulent nasal discharge and respiratory grunts. Few of infected animals died due to septicemia. the necropsy of dead animals was performed and visceral organs lungs, kidneys, heart and lymph nodes were observed for gross and histopathological lesions. The tissue samples from these organs were fixed in formalin for pathological changes. Necropsy of dead animals revealed severe pneumonia, consolidation of lungs and intense pleural adhesions. serosanguinous fluid was accumulated in pericardium and peritoneal cavities. Histopathologically affected lungs exhibited severe congestion, mononuclear cell infiltration, thick interlobular septae punctuated with macrophages, plasma cells and peri-vascular cuffing. Liver, kidneys and lymph nodes had degenerative changes in histological sections. The specificity of p. multocida was determined by colony characteristics on macconkey's agar and morphological features with gram's iodine. The pcr product size approximately 511bp from lung tissues confirmed a total of 82% (19/23) bacterial isolates from dead animals. (author)

Fatal Pasteurella haemolytica pneumonia in bighorn sheep after direct contact with clinically normal domestic sheep.

Science.gov (United States)

Foreyt, W J

1989-03-01

Six Rocky Mountain bighorn sheep were raised in captivity from birth (n = 5) or taken from the wild as a lamb (n = 1). After the bighorn sheep were in captivity for over a year, 6 clinically normal domestic sheep were placed on the 2 ha of pasture on which the bighorn sheep were kept. Nasal swab specimens were obtained from all sheep at the time the domestic sheep were introduced. Pasteurella haemolytica was isolated from swab specimens obtained from 4 of 6 domestic sheep, but not from specimens obtained from the bighorn sheep. All 6 bighorn sheep died of acute hemorrhagic pneumonia after exposure to domestic sheep. Death in the bighorn sheep occurred on days 4, 27, 27, 29, 36, or 71 after initial exposure to domestic sheep. Pasteurella haemolytica was isolated from respiratory tract tissue specimens of all bighorn sheep at the time of death. None of the domestic sheep were clinically ill during the study. At the end of the study, 3 of 6 domestic sheep were euthanatized, and at necropsy, P haemolytica was isolated from 2 of them. The most common serotypes in bighorn and domestic sheep were P haemolytica T-3 and A-2. Other serotypes isolated included P haemolytica A-1, A-9, and A-11 in bighorn sheep and A-1 in domestic sheep. On the basis of results of this study and of other reports, domestic sheep and bighorn sheep should not be managed in proximity to each other because of the potential fatal consequences in bighorn sheep.

Phylogeny of 54 representative strains of species in the family Pasteurellaceae as determined by comparison of 16S rRNA sequences.

Science.gov (United States)

Dewhirst, F E; Paster, B J; Olsen, I; Fraser, G J

1992-03-01

Virtually complete 16S rRNA sequences were determined for 54 representative strains of species in the family Pasteurellaceae. Of these strains, 15 were Pasteurella, 16 were Actinobacillus, and 23 were Haemophilus. A phylogenetic tree was constructed based on sequence similarity, using the Neighbor-Joining method. Fifty-three of the strains fell within four large clusters. The first cluster included the type strains of Haemophilus influenzae, H. aegyptius, H. aphrophilus, H. haemolyticus, H. paraphrophilus, H. segnis, and Actinobacillus actinomycetemcomitans. This cluster also contained A. actinomycetemcomitans FDC Y4, ATCC 29522, ATCC 29523, and ATCC 29524 and H. aphrophilus NCTC 7901. The second cluster included the type strains of A. seminis and Pasteurella aerogenes and H. somnus OVCG 43826. The third cluster was composed of the type strains of Pasteurella multocida, P. anatis, P. avium, P. canis, P. dagmatis, P. gallinarum, P. langaa, P. stomatis, P. volantium, H. haemoglobinophilus, H. parasuis, H. paracuniculus, H. paragallinarum, and A. capsulatus. This cluster also contained Pasteurella species A CCUG 18782, Pasteurella species B CCUG 19974, Haemophilus taxon C CAPM 5111, H. parasuis type 5 Nagasaki, P. volantium (H. parainfluenzae) NCTC 4101, and P. trehalosi NCTC 10624. The fourth cluster included the type strains of Actinobacillus lignieresii, A. equuli, A. pleuropneumoniae, A. suis, A. ureae, H. parahaemolyticus, H. parainfluenzae, H. paraphrohaemolyticus, H. ducreyi, and P. haemolytica. This cluster also contained Actinobacillus species strain CCUG 19799 (Bisgaard taxon 11), A. suis ATCC 15557, H. ducreyi ATCC 27722 and HD 35000, Haemophilus minor group strain 202, and H. parainfluenzae ATCC 29242. The type strain of P. pneumotropica branched alone to form a fifth group. The branching of the Pasteurellaceae family tree was quite complex. The four major clusters contained multiple subclusters. The clusters contained both rapidly and slowly evolving

Pasteurella haemolytica bacteriophage: identification, partial characterization, and relationship of temperate bacteriophages from isolates of Pasteurella haemolytica (biotype A, serotype 1)

International Nuclear Information System (INIS)

Richards, A.B.; Renshaw, H.W.; Sneed, L.W.

1985-01-01

Pasteurella haemolytica (biotype A, serotype 1) isolates (n = 15) from the upper respiratory tract of clinically normal cattle, as well as from lung lesions from cases of fatal bovine pasteurellosis, were examined for the presence of bacteriophage after irradiation with UV light. Treatment of all P haemolytica isolates with UV irradiation resulted in lysis of bacteria due to the induction of vegetative development of bacteriophages. The extent of growth inhibition and bacterial lysis in irradiated cultures was UV dose-dependent. Bacterial cultures exposed to UV light for 20 s reached peak culture density between 60 and 70 minutes after irradiation; thereafter, culture density declined rapidly, so that by 120 minutes, it was approximately 60% of the original value. When examined ultrastructurally, lytic cultures from each isolate revealed bacteriophages with an overall length of approximately 200 nm and that appeared to have a head with icosahedral symmetry and a contractile tail. Cell-free filtrate from each noninduced bacterial isolate was inoculated onto the other bacterial isolates in a cross-culture sensitivity assay for the presence of phages lytic for the host bacterial isolates. Zones of lysis (plaques) did not develop when bacterial lawns grown from the different isolates were inoculated with filtrates from the heterologous isolates

Antimicrobial Susceptibility of Bacteria That Cause Bovine Respiratory Disease Complex in Alberta, Canada

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R. Michele Anholt

2017-12-01

Full Text Available Bovine respiratory disease (BRD is the most important illness of feedlot cattle. Disease management targets the associated bacterial pathogens, Mannheimia haemolytica, Mycoplasma bovis, Pasteurella multocida, Histophilus somni, and Trueperella pyogenes. We conducted a cross-sectional study to measure the frequencies of antimicrobial-resistant BRD pathogens using a collaborative network of veterinarians, industry, government, and a diagnostic laboratory. Seven private veterinary practices in southern Alberta collected samples from both living and dead BRD-affected animals at commercial feedlots. Susceptibility testing of 745 isolates showed that 100% of the M. haemolytica, M. bovis, P. multocida, and T. pyogenes isolates and 66.7% of the H. somni isolates were resistant to at least one antimicrobial class. Resistance to macrolide antimicrobials (90.2% of all isolates was notable for their importance to beef production and human medicine. Multidrug resistance (MDR was high in all target pathogens with 47.2% of the isolates resistant to four or five antimicrobial classes and 24.0% resistance to six to nine classes. We compared the MDR profiles of isolates from two feedlots serviced by different veterinary practices. Differences in the average number of resistant classes were found for M. haemolytica (p < 0.001 and P. multocida (p = 0.002. Compared to previous studies, this study suggests an increasing trend of resistance in BRD pathogens against the antimicrobials used to manage the disease in Alberta. For the veterinary clinician, the results emphasize the importance of ongoing susceptibility testing of BRD pathogens to inform treatment protocols. Surveillance studies that collect additional epidemiological information and manage sampling bias will be necessary to develop strategies to limit the spread of resistance.

Aqueous Humor Antimicrobial Activity: In Vitro Analysis after Topical 0.5% Chloramphenicol Application.

Science.gov (United States)

Cagini, Carlo; Dragoni, Annalisa; Orsolini, Giampaolo; Fiore, Tito; Beccasio, Alfredo; Spadea, Leopoldo; Moretti, Amedeo; Mencacci, Antonella

2017-06-01

To assess aqueous humor antimicrobial activity in vitro after topical 0.5% chloramphenicol application. This investigation included 63 eyes from 65 cataract surgery patients. The study group of 48 eyes received preoperatively four topical applications of 0.5% chloramphenicol. The control group of 15 eyes was given no topical applications. Aqueous humor samples were collected for in vitro antimicrobial analysis using Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Pasteurella multocida organisms by means of disk diffusion test. No inhibition halo was observed around all aqueous humor samples from all chloramphenicol-treated patients, irrespective of the sample quantity added to the paper disks, with no significant difference from aqueous humor from untreated control patients. Aqueous humor displayed no bactericidal effect against any of the microorganisms evaluated after topical 0.5% chloramphenicol application.

Elimination of Pasteurella pneumotropica from a Mouse Barrier Facility by Using a Modified Enrofloxacin Treatment Regimen

Science.gov (United States)

Towne, Justin W; Wagner, April M; Griffin, Kurt J; Buntzman, Adam S; Frelinger, Jeffrey A; Besselsen, David G

2014-01-01

Multiple NOD.Cg-Prkdcscid Il2rgtm1WjlTg(HLA-A2.1)Enge/Sz (NSG/A2) transgenic mice maintained in a mouse barrier facility were submitted for necropsy to determine the cause of facial alopecia, tachypnea, dyspnea, and sudden death. Pneumonia and soft-tissue abscesses were observed, and Pasteurella pneumotropica biotype Jawetz was consistently isolated from the upper respiratory tract, lung, and abscesses. Epidemiologic investigation within the facility revealed presence of this pathogen in mice generated or rederived by the intramural Genetically Engineered Mouse Model (GEMM) Core but not in mice procured from several approved commercial vendors. Epidemiologic data suggested the infection originated from female or vasectomized male ND4 mice obtained from a commercial vendor and then comingled by the GEMM Core to induce pseudopregnancy in female mice for embryo implantation. Enrofloxacin delivered in drinking water (85 mg/kg body weight daily) for 14 d was sufficient to clear bacterial infection in normal, breeding, and immune-deficient mice without the need to change the antibiotic water source. This modified treatment regimen was administered to 2400 cages of mice to eradicate Pasteurella pneumotropica from the facility. Follow-up PCR testing for P. pneumotropica biotype Jawetz remained uniformly negative at 2, 6, 12, and 52 wk after treatment in multiple strains of mice that were originally infected. Together, these data indicate that enrofloxacin can eradicate P. pneumotropica from infected mice in a less labor-intensive approach that does not require breeding cessation and that is easily adaptable to the standard biweekly cage change schedule for individually ventilated cages. PMID:25255075

Elimination of Pasteurella pneumotropica from a mouse barrier facility by using a modified enrofloxacin treatment regimen.

Science.gov (United States)

Towne, Justin W; Wagner, April M; Griffin, Kurt J; Buntzman, Adam S; Frelinger, Jeffrey A; Besselsen, David G

2014-09-01

Multiple NOD. Cg-Prkdc(scid)Il2rg(tm1Wjl)Tg(HLA-A2.1)Enge/Sz (NSG/A2) transgenic mice maintained in a mouse barrier facility were submitted for necropsy to determine the cause of facial alopecia, tachypnea, dyspnea, and sudden death. Pneumonia and soft-tissue abscesses were observed, and Pasteurella pneumotropica biotype Jawetz was consistently isolated from the upper respiratory tract, lung, and abscesses. Epidemiologic investigation within the facility revealed presence of this pathogen in mice generated or rederived by the intramural Genetically Engineered Mouse Model (GEMM) Core but not in mice procured from several approved commercial vendors. Epidemiologic data suggested the infection originated from female or vasectomized male ND4 mice obtained from a commercial vendor and then comingled by the GEMM Core to induce pseudopregnancy in female mice for embryo implantation. Enrofloxacin delivered in drinking water (85 mg/kg body weight daily) for 14 d was sufficient to clear bacterial infection in normal, breeding, and immune-deficient mice without the need to change the antibiotic water source. This modified treatment regimen was administered to 2400 cages of mice to eradicate Pasteurella pneumotropica from the facility. Follow-up PCR testing for P. pneumotropica biotype Jawetz remained uniformly negative at 2, 6, 12, and 52 wk after treatment in multiple strains of mice that were originally infected. Together, these data indicate that enrofloxacin can eradicate P. pneumotropica from infected mice in a less labor-intensive approach that does not require breeding cessation and that is easily adaptable to the standard biweekly cage change schedule for individually ventilated cages.

An ecologic study comparing distribution of Pasteurella trehalosi and Mannheimia haemolytica between Sierra Nevada bighorn sheep, White Mountain bighorn sheep, and domestic sheep.

Science.gov (United States)

Tomassini, Letizia; Gonzales, Ben; Weiser, Glen C; Sischo, William

2009-10-01

The prevalence and phenotypic variability of Pasteurella and Mannheimia isolates from Sierra Nevada bighorn sheep (Ovis canadensis sierrae), White Mountain bighorn sheep (Ovis canadensis nelsoni), and domestic sheep (Ovis aries) from California, USA, were compared. The White Mountain bighorn sheep population had a recent history of pneumonia-associated mortality, whereas the Sierra Nevada bighorn sheep population had no recent history of pneumonia-associated mortality. The domestic sheep flocks were pastured in areas geographically near both populations but were not known to have direct contact with either bighorn sheep population. Oropharyngeal swab samples were collected from healthy domestic and bighorn sheep and cultured to characterize bacterial species, hemolysis, biogroups, and biovariants. Pasteurella trehalosi and Mannheimia haemolytica were detected in all of the study populations, but the relative proportion of each bacterial species differed among sheep populations. Pasteurella trehalosi was more common than M. haemolytica in the bighorn sheep populations, whereas the opposite was true in domestic sheep. Mannheimia haemolytica was separated into 11 biogroups, and P. trehalosi was characterized into two biogroups. Biogroup distributions for M. haemolytica and P. trehalosi differed among the three populations; however, no difference was detected for the distribution of P. trehalosi biogroups between the Sierra Nevada bighorn sheep and domestic sheep. The prevalence odds ratios (pOR) for the distribution of M. haemolytica biogroups suggested little difference between White Mountain bighorn sheep and domestic sheep compared with Sierra Nevada bighorn sheep and domestic sheep, although these comparisons had relatively large confidence intervals for the point estimates. Hemolytic activity of the isolates was not different among the sheep populations for M. haemolytica but was different for P. trehalosi. No clear evidence of association was found in the

Susceptibility of Rocky Mountain bighorn sheep and domestic sheep to pneumonia induced by bighorn and domestic livestock strains of Pasteurella haemolytica.

OpenAIRE

Onderka, D K; Rawluk, S A; Wishart, W D

1988-01-01

Bighorn sheep were inoculated intratracheally with suspensions of nonhemolytic Pasteurella haemolytica biotype T (10(12) organisms) unique to wild bighorns, with beta-hemolytic P. haemolytica biotype T (10(12) organisms) isolated from clinically normal domestic sheep or intradermally with half a dose of a cattle vaccine containing P. haemolytica biotype A (10(5) organisms). The bighorn strain caused lobar necrotizing bronchopneumonia whereas both domestic livestock strains precipitated fatal ...

Monitoring of antimicrobial susceptibility of respiratory tract pathogens isolated from diseased cattle and pigs across Europe, 2009-2012: VetPath results.

Science.gov (United States)

El Garch, Farid; de Jong, Anno; Simjee, Shabbir; Moyaert, Hilde; Klein, Ulrich; Ludwig, Carolin; Marion, Hervé; Haag-Diergarten, Silke; Richard-Mazet, Alexandra; Thomas, Valérie; Siegwart, Ed

2016-10-15

VetPath is an ongoing pan-European antibiotic susceptibility monitoring programme that collects pathogens from diseased cattle, pigs and poultry. In the current study, 996 isolates from cattle and pig respiratory tract infections were tested for their antimicrobial susceptibilities. Non-replicate lung samples or nasopharyngeal/nasal swabs were collected from animals with acute clinical signs in 10 countries during 2009-2012. Pasteurella multocida, Mannheimia haemolytica and Histophilus somni from cattle and P. multocida, Actinobacillus pleuropneumoniae, Haemophilus parasuis, Bordetella bronchiseptica and Streptococcus suis from pigs were isolated by standard methods. S. suis was also isolated from meningitis cases. MIC values of 16 or 17 antibiotics were assessed centrally by broth microdilution following CLSI standards. Results were interpreted using CLSI breakpoints where available. Cattle isolates were generally highly susceptible to most antibiotics, except to tetracycline (3.0-12.0% resistance). Low levels of resistance (0-4.0%) were observed for the macrolide antibiotics. Resistance to spectinomycin varied from 0 to 6.0%. In pig isolates similar observations were made. Resistance to amoxicillin/clavulanic acid, ceftiofur, enrofloxacin, florfenicol, tulathromycin, tiamulin and tilmicosin was absent or <2%. Trimethoprim/sulfamethoxazole resistance varied from 1.9 to 5.3%, but tetracycline resistance varied from 20.4% in P. multocida to 88.1% in S. suis. For most antibiotics and pathogens the percentage resistance remained unchanged or only increased numerically as compared to that of the period 2002-2006. In conclusion, absence or low resistance to antibiotics with defined clinical breakpoints, except for tetracycline, was observed among the major respiratory tract pathogens recovered from livestock. Comparison of all antibiotics and organisms was hampered since for almost half of the antibiotics no CLSI-defined breakpoints were available. Copyright © 2016

مطالعه بر روی ایمنی زایی یک واکسن آزمایشی سپتی سمی هموراژیک با ادجوان روغنی در گاو

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ا. ستوده نیا

2005-01-01

Full Text Available An oil adjuvant vaccine (OAV was prepared from a local strain of Pasteurella multocida. Strain 6:B was cultured and inactivated by formalin. Bacterial pellet was prepared by centrifugation and subsequently adjuvanted by Montannide oil ISA-70. A dose of prepared vaccine containing 3ml (2mg dry weight/ml was injected into five calves by IM route. Animals were bled before and at 24, 90, 150, and 200 days post-vaccination. Collected sera were used in passive mouse protection test (PMPT. Active mouse protection test (AMPT was carried out for OAV according to standard method. Results of PMPT showed 100% protection up to 150 days and 66-83% up to 200 days post-vaccination. In AMPT, 4 log of protection was gained. In this experiment the immunity induced by OAV adjuvanted by ISA-70 could protect the calves.

Combinations of macrolide resistance determinants in field isolates of Mannheimia haemolytica and Pasteurella multocida

DEFF Research Database (Denmark)

Desmolaize, Benoit; Rose, Simon; Wilhelm, Cornelia

2011-01-01

of these species exhibit resistance to veterinary macrolides with phenotypes that fall into three distinct classes. The first class has type I macrolide, lincosamide, and streptogramin B antibiotic resistance and, consistent with this, the 23S rRNA nucleotide A2058 is monomethylated by the enzyme product......(E) genes within an isogenic Escherichia coli background to assess their individually contributions to resistance. Our findings indicate what types of compounds might have driven the selection for these resistance determinants....

Purification, crystallization and preliminary crystallographic characterization of the α2,6-sialyltransferase from Photobacterium sp. JT-ISH-224

International Nuclear Information System (INIS)

Okino, Nozomu; Kakuta, Yoshimitsu; Kajiwara, Hitomi; Ichikawa, Masako; Takakura, Yoshimitsu; Ito, Makoto; Yamamoto, Takeshi

2007-01-01

Crystallization of the α2,6-sialyltransferase from Photobacterium. Sialyltransferases transfer sialic acid from cytidine-5-monophospho-N-acetylneuraminic acid (CMP-NeuAc) to the nonreducing termini of the oligosaccharyl structures of various glycoproteins and glycolipids. The newly cloned α2,6-sialyltransferase from Photobacterium sp. JT-ISH-224 (from the Vibrionaceae family) is composed of two domains: an unknown N-terminal domain and a catalytic C-terminal domain which shares significant homology with the Pasteurella multocida multifunctional sialyltransferase. The putative mature form of JT-ISH-224 α2,6-sialyltransferase was overproduced in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method at 293 K. The crystal belonged to space group P3 1 21 or P3 2 21, with unit-cell parameters a = b = 90.29, c = 204.33 Å. X-ray diffraction data were collected to 2.5 Å resolution

Pneumonia in slaughtered sheep in south-western Iran: pathological characteristics and aerobic bacterial aetiology.

Science.gov (United States)

Azizi, Shahrzad; Korani, Farzad Shahrani; Oryan, Ahmad

2013-01-01

In this study, the lungs of 1,000 sheep carcasses were subjected to gross examination and those suspected to be infected with pneumonia were studied at histopathological level as well as examined for presence of bacteria. Pneumonia was detected in 42 (4.2%) carcasses. Based on histopathological lesions, 45.24% were affected with suppurative bronchopneumonia, 20.93% with interstitial pneumonia, 11.9% bronchointerstitial pneumonia, 7.14% with fibrinous bronchopneumonia and 2.38% with embolic pneumonia. In addition, 11.9% of the lungs showed lung abscesses and 2.33% were affected with pleuritis without involving pulmonary parenchyma. Bacteriological examination revealed presence of ovine pathogens, such as Pasteurella multocida (24.53%), Staphylococcus aureus (20.75%), Klebsiella pneumoniae (15.09%), Corynebacterium pseudotuberculosis (7.55%) and Actinomyces pyogenes (1.89%). The most common form of pneumonia was suppurative bronchopneumonia with moderate amounts of fibrin deposits on the pleural surface and inside the bronchioles and alveoli.

Development of colloidal gold immunochromatographic strips for detection of Riemerella anatipestifer.

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Wanwan Hou

Full Text Available Riemerella anatipestifer is one of the most important bacterial pathogen of ducks and causes a contagious septicemia. R. anatipestifer infection causes serositis syndromes similar to other bacterial infections in ducks, including infection by Escherichia coli, Salmonella enterica and Pasteurella multocida. Clinically differentiating R. anatipestifer infections from other bacterial pathogen infections is usually difficult. In this study, MAb 1G2F10, a monoclonal antibody against R. anatipestifer GroEL, was used to develop a colloidal gold immunochromatographic strip. Colloidal gold particles were prepared by chemical synthesis to an average diameter of 20 ± 5.26 nm by transmission electron microscope imaging. MAb 1G2F10 was conjugated to colloidal gold particles and the formation of antibody-colloidal gold conjugates was monitored by UV/Vis spectroscopy. Immunochromatographic strips were assembled in regular sequence through different accessories sticked on PVC plate. Strips specifically detected R. anatipestifer within 10 min, but did not detect E. coli, S. enterica and P. multocida. The detection limit for R. anatipestifer was 1 × 10(6 colony forming units, which was 500 times higher than a conventional agglutination test. Accuracy was 100% match to multiplex PCR. Assay stability and reproducibility were excellent after storage at 4°C for 6 months. The immunochromatographic strips prepared in this study offer a specific, sensitive, and rapid detection method for R. anatipestifer, which is of great importance for the prevention and control of R. anatipestifer infections.

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

[Transformation from chronic subdural hematoma into subdural empyema following cat bites: a case report].

Science.gov (United States)

Konno, Takuya; Yamada, Kei; Kasahara, Sou; Umeda, Yoshitaka; Oyake, Mutsuo; Fujita, Nobuya

2015-01-01

A 69-year-old man developed motor aphasia and right hemiparesis with severe headache, during the treatment of cellulitis and sepsis due to cat bites. Brain CT showed a low density, crescent-shaped lesion in the left subdural space, which was hypointense on brain diffusion-weighted imaging (DWI). One week later, when his neurological symptoms had worsened, the signal of the subdural lesion had changed to hyperintense on DWI. The lesion was capsule-shaped when enhanced by Gadolinium. The signal changes on DWI of the lesion indicated the existing hematoma had changed to an empyema, or so-called infected subdural hematoma, due to a hematogenous bacterial infection. Pasteurella multocida, a resident microbe in the oral cavity of cats, could be the responsible pathogen in this case. The patient recovered completely after treatment with intravenous high dose antibiotics. This is an important case report describing the transformation from a chronic subdural hematoma into a subdural empyema by DWI.

Clinical and microbiological study of otitis externa in sheep

Directory of Open Access Journals (Sweden)

M. I. Al-Farwachi

2008-01-01

Full Text Available In this study one hundred Awassi sheep were examined clinically and bacteriologically for isolation and identification of the bacterial agents of otitis externa in sheep. The main clinical signs appeared included weakness, pale mucus membrane, auricular discharge, cough, anorexia, emaciation, and nasal discharge. Results revealed isolation of bacteria from (45% examined swabs. The most being from right ear. Younger animals were more frequently infected than older animals. Pseudomonas aeruginosa, Staphylococcus aureus, Mannheimia haemolytica, Staph. epidermidis, Pasteurella multocida, Streptococcus spp., Acintobacter spp., Escherichia coli and Klebsiella pneumonia were isolated. The results revealed that the most bacterial isolates were resistance to the bactericidal effect of the normal serum included Streptococcus pneumonia, Staphylococcus aureus, Mannheimia haemolytica. While the most bacterial isolates were produced hydroxymate siderophore included Staphylococcus aureus, Mannheimia haemolytica, Streptococcus pneumonia. The obtained results indicated to the importance of determination of serum resistance as a bacterial virulence factor in otitis externa in sheep.

New derivatives of salicylamides: Preparation and antimicrobial activity against various bacterial species.

Science.gov (United States)

Pauk, Karel; Zadražilová, Iveta; Imramovský, Aleš; Vinšová, Jarmila; Pokorná, Michaela; Masaříková, Martina; Cížek, Alois; Jampílek, Josef

2013-11-01

Three series of salicylanilides, esters of N-phenylsalicylamides and 2-hydroxy-N-[1-(2-hydroxyphenylamino)-1-oxoalkan-2-yl]benzamides, in total thirty target compounds were synthesized and characterized. The compounds were evaluated against seven bacterial and three mycobacterial strains. The antimicrobial activities of some compounds were comparable or higher than the standards ampicillin, ciprofloxacin or isoniazid. Derivatives 3f demonstrated high biological activity against Staphylococcus aureus (⩽0.03μmol/L), Mycobacterium marinum (⩽0.40μmol/L) and Mycobacterium kansasii (1.58μmol/L), 3g shows activity against Clostridium perfringens (⩽0.03μmol/L) and Bacillus cereus (0.09μmol/L), 3h against Pasteurella multocida (⩽0.03μmol/L) and M. kansasii (⩽0.43μmol/L), 3i against methicillin-resistant S. aureus and B. cereus (⩽0.03μmol/L). The structure-activity relationships are discussed for all the compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

Aerobic bacteria occurring in the vagina of bitches with reproductive disorders.

Science.gov (United States)

Bjurström, L

1993-01-01

A retrospective survey was performed of aerobic bacterial species found in the vagina of 203 bitches with genital disorders, e.g. infertility, vaginitis, pyometra and puppy death. Escherichia coli, beta-hemolytic streptococci, Staphylococcus intermedius and Pasteurella multocida were the species most often isolated. From bitches with pyometra E. coli in pure culture was the most frequent isolate. In contrast, the majority of infertile bitches gave rise to mixed cultures, and no specific bacterial species was consistently associated with infertility. Thus, bacterial sampling from infertile bitches was concluded to be of low diagnostic value. Bacterial species isolated from the bitches having vaginitis were present in pure culture in 26.9% of the samples while nonspecific mixed cultures were obtained from 34.6% of the samples from these bitches. E. coli was the most frequently isolated bacterial species from bitches with dead puppies. However, in such cases it is important to relate the vaginal bacterial findings to autopsy findings and the results of bacteriological cultures of the pups.

Causes of Pneumonia Epizootics among Bighorn Sheep, Western United States, 2008–2010

Science.gov (United States)

Highland, Margaret A.; Baker, Katherine; Cassirer, E. Frances; Anderson, Neil J.; Ramsey, Jennifer M.; Mansfield, Kristin; Bruning, Darren L.; Wolff, Peregrine; Smith, Joshua B.; Jenks, Jonathan A.

2012-01-01

Epizootic pneumonia of bighorn sheep is a devastating disease of uncertain etiology. To help clarify the etiology, we used culture and culture-independent methods to compare the prevalence of the bacterial respiratory pathogens Mannheimia haemolytica, Bibersteinia trehalosi, Pasteurella multocida, and Mycoplasma ovipneumoniae in lung tissue from 44 bighorn sheep from herds affected by 8 outbreaks in the western United States. M. ovipneumoniae, the only agent detected at significantly higher prevalence in animals from outbreaks (95%) than in animals from unaffected healthy populations (0%), was the most consistently detected agent and the only agent that exhibited single strain types within each outbreak. The other respiratory pathogens were frequently but inconsistently detected, as were several obligate anaerobic bacterial species, all of which might represent secondary or opportunistic infections that could contribute to disease severity. These data provide evidence that M. ovipneumoniae plays a primary role in the etiology of epizootic pneumonia of bighorn sheep. PMID:22377321

Causes of pneumonia epizootics among bighorn sheep, Western United States, 2008-2010.

Science.gov (United States)

Besser, Thomas E; Highland, Margaret A; Baker, Katherine; Cassirer, E Frances; Anderson, Neil J; Ramsey, Jennifer M; Mansfield, Kristin; Bruning, Darren L; Wolff, Peregrine; Smith, Joshua B; Jenks, Jonathan A

2012-03-01

Epizootic pneumonia of bighorn sheep is a devastating disease of uncertain etiology. To help clarify the etiology, we used culture and culture-independent methods to compare the prevalence of the bacterial respiratory pathogens Mannheimia haemolytica, Bibersteinia trehalosi, Pasteurella multocida, and Mycoplasma ovipneumoniae in lung tissue from 44 bighorn sheep from herds affected by 8 outbreaks in the western United States. M. ovipneumoniae, the only agent detected at significantly higher prevalence in animals from outbreaks (95%) than in animals from unaffected healthy populations (0%), was the most consistently detected agent and the only agent that exhibited single strain types within each outbreak. The other respiratory pathogens were frequently but inconsistently detected, as were several obligate anaerobic bacterial species, all of which might represent secondary or opportunistic infections that could contribute to disease severity. These data provide evidence that M. ovipneumoniae plays a primary role in the etiology of epizootic pneumonia of bighorn sheep.

Pneumonia in slaughtered sheep in south-western Iran: pathological characteristics and aerobic bacterial aetiology

Directory of Open Access Journals (Sweden)

Shahrzad Azizi

2013-03-01

Full Text Available In this study, the lungs of 1,000 sheep carcasses were subjected to gross examination and those suspected to be infected with pneumonia were studied at histopathological level as well as examined for presence of bacteria. Pneumonia was detected in 42 (4.2% carcasses. Based on histopathological lesions, 45.24% were affected with suppurative bronchopneumonia, 20.93% with interstitial pneumonia, 11.9% bronchointerstitial pneumonia, 7.14% with fibrinous bronchopneumonia and 2.38% with embolic pneumonia. In addition, 11.9% of the lungs showed lung abscesses and 2.33% were affected with pleuritis without involving pulmonary parenchyma. Bacteriological examination revealed presence of ovine pathogens, such as Pasteurella multocida (24.53%, Staphylococcus aureus (20.75%, Klebsiella pneumoniae (15.09%, Corynebacterium pseudotuberculosis (7.55% and Actinomyces pyogenes (1.89%. The most common form of pneumonia was suppurative bronchopneumonia with moderate amounts of fibrin deposits on the pleural surface and inside the bronchioles and alveoli.

Bovine mastitis caused by gram negative bacteria in Mosul

Directory of Open Access Journals (Sweden)

S. Y. A. Al-Dabbagh

2012-01-01

Full Text Available A total of 90 milk samples were collected from cows with clinical and subclinical mastitis from different areas in Mosul city, in a period from October 2009 to June 2010, for the detection of gram negative bacteriological causative agents. The bacteria were identified using morphological, cultural and biochemical characteristics. thirty tow (35.3% gram negative bacterial isolates were obtained from the total count which included 14 isolates (15.5% for Escherichia coli, 7 isolates (7.7% for Klebsiella spp, 4 isolates (4.4% for Pseudomonas aeruginosa, 3 isolates (3.3% for Enterobacter aerogenes ,2 isolates for Serratia marcescens and one isolates (1.1% for each of Aeromonas hydrophila and Pasteurella multocida. Results of antibiotic sensitivity test indicated that most of these isolates were sensitive to Ciprofloxacin following by Gentamycin and Cotrimoxazole, while most of these organisms were resistant to Ampicillin, the isolates showed different percentages of sensitivity to Doxycycline, Tetracycline, Neomycin and Chloramphenicol.

Mutant prevention concentration, pharmacokinetic-pharmacodynamic integration, and modeling of enrofloxacin data established in diseased buffalo calves.

Science.gov (United States)

Ramalingam, B; Sidhu, P K; Kaur, G; Venkatachalam, D; Rampal, S

2015-12-01

The pharmacokinetic-pharmacodynamic (PK/PD) modeling of enrofloxacin data using mutant prevention concentration (MPC) of enrofloxacin was conducted in febrile buffalo calves to optimize dosage regimen and to prevent the emergence of antimicrobial resistance. The serum peak concentration (Cmax ), terminal half-life (t1/2 K10) , apparent volume of distribution (Vd(area) /F), and mean residence time (MRT) of enrofloxacin were 1.40 ± 0.27 μg/mL, 7.96 ± 0.86 h, 7.74 ± 1.26 L/kg, and 11.57 ± 1.01 h, respectively, following drug administration at dosage 12 mg/kg by intramuscular route. The minimum inhibitory concentration (MIC), minimum bactericidal concentration, and MPC of enrofloxacin against Pasteurella multocida were 0.055, 0.060, and 1.45 μg/mL, respectively. Modeling of ex vivo growth inhibition data to the sigmoid Emax equation provided AUC24 h /MIC values to produce effects of bacteriostatic (33 h), bactericidal (39 h), and bacterial eradication (41 h). The estimated daily dosage of enrofloxacin in febrile buffalo calves was 3.5 and 8.4 mg/kg against P. multocida/pathogens having MIC90 ≤0.125 and 0.30 μg/mL, respectively, based on the determined AUC24 h /MIC values by modeling PK/PD data. The lipopolysaccharide-induced fever had no direct effect on the antibacterial activity of the enrofloxacin and alterations in PK of the drug, and its metabolite will be beneficial for its use to treat infectious diseases caused by sensitive pathogens in buffalo species. In addition, in vitro MPC data in conjunction with in vivo PK data indicated that clinically it would be easier to eradicate less susceptible strains of P. multocida in diseased calves. © 2015 John Wiley & Sons Ltd.

Mortalidad por meningitis por Pasteurella canis. Oportunidades de aprendizaje

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Ana Rosa Ropero Vera

2016-01-01

Full Text Available La meningitis bacteriana es una enfermedad importante de distribución mundial, causa mayor y sustancial de mortalidad y morbilidad en países en desarrollo. La Organización Mundial de la Salud (OMS sostiene que la meningitis es una de las diez afecciones principales del ser humano y debe ser considerada como una emergencia infectológica; por eso es fundamental reconocer que esta enfermedad es causa de muerte en niños de todo el mundo, sin distinción de raza, nivel económico o sociocultural. Se realizó una investigación de caso en menor de 53 días de nacido, que cumplía con los criterios clínicos y de laboratorio compatible con meningitis bacteriana, con el propósito de analizar y fortalecer la toma de decisiones en salud pública por parte de la secretaría local de salud del municipio de Valledupar (Colombia. Entre los hallazgos se encontró antecedentes infecciosos en el menor, coloración de Gram y cultivo de LCR, en el que se identificó cocobacilos Gram negativos, que fueron aislados como agente causal Pasteurella canis. Este estudio pretende sensibilizar a los prestadores de salud para que cuenten con personal altamente capacitado para brindar tratamientos adecuados y prevenir complicaciones en la meningitis bacteriana en niños, y así disminuir la posibilidad de secuelas o muerte, tanto en pacientes con compromiso inmunológico o sin este.

Anti-BACE1 and Antimicrobial Activities of Steroidal Compounds Isolated from Marine Urechis unicinctus

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Yong-Zhe Zhu

2018-03-01

Full Text Available The human β-site amyloid cleaving enzyme (BACE1 has been considered as an effective drug target for treatment of Alzheimer’s disease (AD. In this study, Urechis unicinctus (U. unicinctus, which is a Far East specialty food known as innkeeper worm, ethanol extract was studied by bioassay-directed fractionation and isolation to examine its potential β-site amyloid cleaving enzyme inhibitory and antimicrobial activity. The following compounds were characterized: hecogenin, cholest-4-en-3-one, cholesta-4,6-dien-3-ol, and hurgadacin. These compounds were identified by their mass spectrometry, 1H, and 13C NMR spectral data, comparing those data with NIST/EPA/NIH Mass spectral database (NIST11 and published values. Hecogenin and cholest-4-en-3-one showed significant inhibitory activity against BACE1 with EC50 values of 116.3 and 390.6 µM, respectively. Cholesta-4,6-dien-3-ol and hurgadacin showed broad spectrum antimicrobial activity, particularly strongly against Escherichia coli (E. coli, Salmonella enterica (S. enterica, Pasteurella multocida (P. multocida, and Physalospora piricola (P. piricola, with minimal inhibitory concentration (MIC ranging from 0.46 to 0.94 mg/mL. This is the first report regarding those four known compounds that were isolated from U. unicinctus and their anti-BACE1 and antimicrobial activity, highlighting the fact that known natural compounds may be a critical source of new medicine leads. These findings provide scientific evidence for potential application of those bioactive compounds for the development of AD drugs and antimicrobial agents.

Anti-BACE1 and Antimicrobial Activities of Steroidal Compounds Isolated from Marine Urechis unicinctus.

Science.gov (United States)

Zhu, Yong-Zhe; Liu, Jing-Wen; Wang, Xue; Jeong, In-Hong; Ahn, Young-Joon; Zhang, Chuan-Jie

2018-03-14

The human β-site amyloid cleaving enzyme (BACE1) has been considered as an effective drug target for treatment of Alzheimer's disease (AD). In this study, Urechis unicinctus (U. unicinctus) , which is a Far East specialty food known as innkeeper worm, ethanol extract was studied by bioassay-directed fractionation and isolation to examine its potential β-site amyloid cleaving enzyme inhibitory and antimicrobial activity. The following compounds were characterized: hecogenin, cholest-4- en -3-one, cholesta-4,6- dien -3-ol, and hurgadacin. These compounds were identified by their mass spectrometry, ¹H, and 13 C NMR spectral data, comparing those data with NIST/EPA/NIH Mass spectral database (NIST11) and published values. Hecogenin and cholest-4- en -3-one showed significant inhibitory activity against BACE1 with EC 50 values of 116.3 and 390.6 µM, respectively. Cholesta-4,6- dien -3-ol and hurgadacin showed broad spectrum antimicrobial activity, particularly strongly against Escherichia coli (E. coli) , Salmonella enterica (S. enterica) , Pasteurella multocida (P. multocida) , and Physalospora piricola (P. piricola) , with minimal inhibitory concentration (MIC) ranging from 0.46 to 0.94 mg/mL. This is the first report regarding those four known compounds that were isolated from U. unicinctus and their anti-BACE1 and antimicrobial activity, highlighting the fact that known natural compounds may be a critical source of new medicine leads. These findings provide scientific evidence for potential application of those bioactive compounds for the development of AD drugs and antimicrobial agents.

Aerobic bacteria from mucous membranes, ear canals, and skin wounds of feral cats in Grenada, and the antimicrobial drug susceptibility of major isolates.

Science.gov (United States)

Hariharan, Harry; Matthew, Vanessa; Fountain, Jacqueline; Snell, Alicia; Doherty, Devin; King, Brittany; Shemer, Eran; Oliveira, Simone; Sharma, Ravindra N

2011-03-01

In a 2-year period 54 feral cats were captured in Grenada, West Indies, and a total of 383 samples consisting of swabs from rectum, vagina, ears, eyes, mouth, nose and wounds/abscesses, were cultured for aerobic bacteria and campylobacters. A total of 251 bacterial isolates were obtained, of which 205 were identified to species level and 46 to genus level. A commercial bacterial identification system (API/Biomerieux), was used for this purpose. The most common species was Escherichia coli (N=60), followed by Staphylococcus felis/simulans (40), S. hominis (16), S. haemolyticus (12), Streptococcus canis (9), Proteus mirabilis (8), Pasteurella multocida (7), Streptococcus mitis (7), Staphylococcus xylosus (7), S. capitis (6), S. chromogenes (4), S. sciuri (3), S. auricularis (2), S. lentus (2), S. hyicus (2), Streptococcus suis (2) and Pseudomonas argentinensis (2). Sixteen other isolates were identified to species level. A molecular method using 16S rRNA sequencing was used to confirm/identify 22 isolates. Salmonella or campylobacters were not isolated from rectal swabs. E. coli and S. felis/simulans together constituted 50% of isolates from vagina. S. felis/simulans was the most common species from culture positive ear and eye samples. P. multocida was isolated from 15% of mouth samples. Coagulase-negative staphylococci were the most common isolates from nose and wound swabs. Staphylococcus aureus, or S. intemedius/S. pseudintermedius were not isolated from any sample. Antimicrobial drug resistance was minimal, most isolates being susceptible to all drugs tested against, including tetracycline. Copyright © 2010 Elsevier Ltd. All rights reserved.

Recombinant Programming

OpenAIRE

Pawlak , Renaud; Cuesta , Carlos; Younessi , Houman

2004-01-01

This research report presents a promising new approach to computation called Recombinant Programming. The novelty of our approach is that it separates the program into two layers of computation: the recombination and the interpretation layer. The recombination layer takes sequences as inputs and allows the programmer to recombine these sequences through the definition of cohesive code units called extensions. The output of such recombination is a mesh that can be used by the interpretation la...

Recombiner

International Nuclear Information System (INIS)

Kikuchi, Nobuo.

1983-01-01

Purpose: To shorten the pre-heating time for a recombiner and obtain a uniform temperature distribution for the charged catalyst layer in a BWR type reactor. Constitution: A pre-heating heater is disposed to the outer periphery of a vessel for a recombiner packed with catalysts for recombining hydrogen and oxygen in gases flowing through a radioactive gaseous wastes processing system. Heat pipes for transmitting the heat applied to said container to the catalyst are disposed vertically and horizontally within the container. Different length of the heat pipes are combined. In this way, pre-heating time for the recombiner before the operation start and before the system switching can be shortened and the uniform pre-heating for the inside of the recombiner is also made possible. Further, heater control in the pre-heating can be carried out effectively and with ease. (Moriyama, K.)

Aerobic salivary bacteria in wild and captive Komodo dragons.

Science.gov (United States)

Montgomery, Joel M; Gillespie, Don; Sastrawan, Putra; Fredeking, Terry M; Stewart, George L

2002-07-01

During the months of November 1996, August 1997, and March 1998, saliva and plasma samples were collected for isolation of aerobic bacteria from 26 wild and 13 captive Komodo dragons (Varanus komodoensis). Twenty-eight Gram-negative and 29 Gram-positive species of bacteria were isolated from the saliva of the 39 Komodo dragons. A greater number of wild than captive dragons were positive for both Gram-negative and Gram-positive bacteria. The average number of bacterial species within the saliva of wild dragons was 46% greater than for captive dragons. While Escherichia coli was the most common bacterium isolated from the saliva of wild dragons, this species was not present in captive dragons. The most common bacteria isolated from the saliva of captive dragons were Staphylococcus capitis and Staphylococcus capitis and Staphylococcus caseolyticus, neither of which were found in wild dragons. High mortality was seen among mice injected with saliva from wild dragons and the only bacterium isolated from the blood of dying mice was Pasteurella multocida. A competitive inhibition enzyme-linked immunosorbent assay revealed the presence of anti-Pasteurella antibody in the plasma of Komodo dragons. Four species of bacteria isolated from dragon saliva showed resistance to one or more of 16 antimicrobics tested. The wide variety of bacteria demonstrated in the saliva of the Komodo dragon in this study, at least one species of which was highly lethal in mice and 54 species of which are known pathogens, support the observation that wounds inflicted by this animal are often associated with sepsis and subsequent bacteremia in prey animals.

Photoionization and Recombination

Science.gov (United States)

Nahar, Sultana N.

2000-01-01

Theoretically self-consistent calculations for photoionization and (e + ion) recombination are described. The same eigenfunction expansion for the ion is employed in coupled channel calculations for both processes, thus ensuring consistency between cross sections and rates. The theoretical treatment of (e + ion) recombination subsumes both the non-resonant recombination ("radiative recombination"), and the resonant recombination ("di-electronic recombination") processes in a unified scheme. In addition to the total, unified recombination rates, level-specific recombination rates and photoionization cross sections are obtained for a large number of atomic levels. Both relativistic Breit-Pauli, and non-relativistic LS coupling, calculations are carried out in the close coupling approximation using the R-matrix method. Although the calculations are computationally intensive, they yield nearly all photoionization and recombination parameters needed for astrophysical photoionization models with higher precision than hitherto possible, estimated at about 10-20% from comparison with experimentally available data (including experimentally derived DR rates). Results are electronically available for over 40 atoms and ions. Photoionization and recombination of He-, and Li-like C and Fe are described for X-ray modeling. The unified method yields total and complete (e+ion) recombination rate coefficients, that can not otherwise be obtained theoretically or experimentally.

Preliminary clinical pharmacological investigations of tylosin and tiamulin in chickens.

Science.gov (United States)

Ziv, G

1980-10-15

The minimal inhibitory concentrations (MIC) of tiamulin and tylosin for mycoplasma, Gram-positive, and Gram-negative micro-organisms isolated from chickens were determinated by the agar dilution method. Median MIC values for tiamulin against Mycoplasma gallisepticum (0.05 microgram/ml) and Mycoplasma synoviae (0.10 microgram/ml) were 2 to 4 times lower than the corresponding values for tylosin. Tiamulin was also slightly more effective in vitro in inhibiting Escherichia coli, Pasteurella multocida, and beta-haemolytic streptococci than was tylosin. Groups of chicken were offered tiamulin medicated drinking water at rates of 125 and 250 mg/litre for 48 hours. Average serum tiamulin concentrations were 0.38 and 0.78 microgram/ml, respectively. When tylosin tartrate was added to the drinking water at 500 and 700 mg/litre, average serum drug levels were 0.12 and 0.17 microgram/ml, respectively. Tiamulin was 45% bound in chicken serum, as against 30% serum protein binding for tylosin. Correlations were made between free (non protein bound) serum drug levels and the MIC values of the two drugs. Such comparisons suggest that when tiamulin is given in the drinking water at rates of 125 to 250 mg/litre, better antimycoplasmal activity is to be expected in vivo than by giving tylosin tartrate in the drinking water at 500 to 700 mg/litre. Based on these data, no clinical efficacy of these dose rates can be expected in flocks infected by gram-negative micro-organisms such as E. coli or P. multocida. The tylosin tartrate rate of 500 to 700 mg/litre, may be clinical ineffective the treatment of Staphylococcus aureus infections.

Dose dependency of outcomes of intrapleural fibrinolytic therapy in new rabbit empyema models

Science.gov (United States)

Florova, Galina; Azghani, Ali O.; Buchanan, Ann; Boren, Jake; Allen, Timothy; Rahman, Najib M.; Koenig, Kathleen; Chamiso, Mignote; Karandashova, Sophia; Henry, James; Idell, Steven

2016-01-01

The incidence of empyema (EMP) is increasing worldwide; EMP generally occurs with pleural loculation and impaired drainage is often treated with intrapleural fibrinolytic therapy (IPFT) or surgery. A number of IPFT options are used clinically with empiric dosing and variable outcomes in adults. To evaluate mechanisms governing intrapleural fibrinolysis and disease outcomes, models of Pasteurella multocida and Streptococcus pneumoniae were generated in rabbits and the animals were treated with either human tissue (tPA) plasminogen activator or prourokinase (scuPA). Rabbit EMP was characterized by the development of pleural adhesions detectable by chest ultrasonography and fibrinous coating of the pleura. Similar to human EMP, rabbits with EMP accumulated sizable, 20- to 40-ml fibrinopurulent pleural effusions associated with extensive intrapleural organization, significantly increased pleural thickness, suppression of fibrinolytic and plasminogen-activating activities, and accumulation of high levels of plasminogen activator inhibitor 1, plasminogen, and extracellular DNA. IPFT with tPA (0.145 mg/kg) or scuPA (0.5 mg/kg) was ineffective in rabbit EMP (n = 9 and 3 for P. multocida and S. pneumoniae, respectively); 2 mg/kg tPA or scuPA IPFT (n = 5) effectively cleared S. pneumoniae-induced EMP collections in 24 h with no bleeding observed. Although intrapleural fibrinolytic activity for up to 40 min after IPFT was similar for effective and ineffective doses of fibrinolysin, it was lower for tPA than for scuPA treatments. These results demonstrate similarities between rabbit and human EMP, the importance of pleural fluid PAI-1 activity, and levels of plasminogen in the regulation of intrapleural fibrinolysis and illustrate the dose dependency of IPFT outcomes in EMP. PMID:27343192

Ceftiofur sodium, a broad-spectrum cephalosporin: evaluation in vitro and in vivo in mice.

Science.gov (United States)

Yancey, R J; Kinney, M L; Roberts, B J; Goodenough, K R; Hamel, J C; Ford, C W

1987-07-01

Ceftiofur sodium, a broad-spectrum beta-lactamase-resistant cephalosporin, was evaluated in vitro and in vivo in mice. Ceftiofur is the sodium salt of (6R, 7R)-7[( 2-amino-4-thiazolyl)-Z- (methoxyimino)acetyl]amino)-3-[( (2-furanylcarbonyl)thio]methyl)-8-oxo-5- thia-1-azabicyclo-[4.2.0]oct-2-ene-2-carboxylate. Minimal inhibitory concentration values were obtained with 264 strains representing 9 genera and 17 species of bacterial pathogens from cattle, swine, sheep, horses, poultry, dogs, cats, and human beings. Ceftiofur was more active than was ampicillin against all strains tested including beta-lactamase-producing organisms. In mice with systemic infections, ceftiofur was more active than or equivalent to ampicillin, cephalothin, cefamandole, cloxacillin, cefoperazone, or pirlimycin. These protection tests included infections with Escherichia coli, Haemophilus pleuropneumoniae, H somnus, Pasteurella haemolytica, P multocida, Salmonella typhimurium, or Staphylococcus aureus. In infant mice with E coli-induced lethal diarrhea and in mice with S aureus and E coli-induced mastitis, ceftiofur was comparable or more active than was ampicillin.

Granzyme A Produces Bioactive IL-1β through a Nonapoptotic Inflammasome-Independent Pathway

Directory of Open Access Journals (Sweden)

Dagmar Hildebrand

2014-11-01

Full Text Available Bacterial components are recognized by the immune system through activation of the inflammasome, eventually causing processing of the proinflammatory cytokine interleukin-1β (IL-1β, a pleiotropic cytokine and one of the most important mediators of inflammation, through the protease caspase-1. Synthesis of the precursor protein and processing into its bioactive form are tightly regulated, given that disturbed control of IL-1β release can cause severe autoinflammatory diseases or contribute to cancer development. We show that the bacterial Pasteurella multocida toxin (PMT triggers Il1b gene transcription in macrophages independently of Toll-like receptor signaling through RhoA/Rho-kinase-mediated NF-κΒ activation. Furthermore, PMT mediates signal transducer and activator of transcription (STAT protein-controlled granzyme A (a serine protease expression in macrophages. The exocytosed granzyme A enters target cells and mediates IL-1β maturation independently of caspase-1 and without inducing cytotoxicity. These findings show that macrophages can induce an IL-1β-initiated immune response independently of inflammasome activity.

Recombiner

International Nuclear Information System (INIS)

Osumi, Morimichi.

1979-01-01

Purpose: To provide a recombiner which is capable of converting hydrogen gas into water by use of high-frequency heating at comparatively low temperatures and is safe and cheap in cost. Constitution: Hydrogen gas is introduced from an outer pipeline to the main structure of a recombiner, and when it passes through the vicinity of the central part of the recombiner, it is reacted with copper oxide (CuO 2 ) heated to a temperature more than 300 0 C by a high-frequency heater, and converted gently into water by reduction operation (2H 2 + CuO 2 → Cu + 2H 2 O). The thus prepared water is exhausted through the outer pipeline to a suppression pool. A part of hydrogen gas which has not been converted completely into water by the reaction and is remaining as hydrogen is recovered through exhaust nozzles and again introduced into the main structure of the recombiner. (Yoshino, Y.)

Genome-wide recombination rate variation in a recombination map of cotton.

Science.gov (United States)

Shen, Chao; Li, Ximei; Zhang, Ruiting; Lin, Zhongxu

2017-01-01

Recombination is crucial for genetic evolution, which not only provides new allele combinations but also influences the biological evolution and efficacy of natural selection. However, recombination variation is not well understood outside of the complex species' genomes, and it is particularly unclear in Gossypium. Cotton is the most important natural fibre crop and the second largest oil-seed crop. Here, we found that the genetic and physical maps distances did not have a simple linear relationship. Recombination rates were unevenly distributed throughout the cotton genome, which showed marked changes along the chromosome lengths and recombination was completely suppressed in the centromeric regions. Recombination rates significantly varied between A-subgenome (At) (range = 1.60 to 3.26 centimorgan/megabase [cM/Mb]) and D-subgenome (Dt) (range = 2.17 to 4.97 cM/Mb), which explained why the genetic maps of At and Dt are similar but the physical map of Dt is only half that of At. The translocation regions between A02 and A03 and between A04 and A05, and the inversion regions on A10, D10, A07 and D07 indicated relatively high recombination rates in the distal regions of the chromosomes. Recombination rates were positively correlated with the densities of genes, markers and the distance from the centromere, and negatively correlated with transposable elements (TEs). The gene ontology (GO) categories showed that genes in high recombination regions may tend to response to environmental stimuli, and genes in low recombination regions are related to mitosis and meiosis, which suggested that they may provide the primary driving force in adaptive evolution and assure the stability of basic cell cycle in a rapidly changing environment. Global knowledge of recombination rates will facilitate genetics and breeding in cotton.

Fine-Scale Recombination Maps of Fungal Plant Pathogens Reveal Dynamic Recombination Landscapes and Intragenic Hotspots.

Science.gov (United States)

Stukenbrock, Eva H; Dutheil, Julien Y

2018-03-01

Meiotic recombination is an important driver of evolution. Variability in the intensity of recombination across chromosomes can affect sequence composition, nucleotide variation, and rates of adaptation. In many organisms, recombination events are concentrated within short segments termed recombination hotspots. The variation in recombination rate and positions of recombination hotspot can be studied using population genomics data and statistical methods. In this study, we conducted population genomics analyses to address the evolution of recombination in two closely related fungal plant pathogens: the prominent wheat pathogen Zymoseptoria tritici and a sister species infecting wild grasses Z. ardabiliae We specifically addressed whether recombination landscapes, including hotspot positions, are conserved in the two recently diverged species and if recombination contributes to rapid evolution of pathogenicity traits. We conducted a detailed simulation analysis to assess the performance of methods of recombination rate estimation based on patterns of linkage disequilibrium, in particular in the context of high nucleotide diversity. Our analyses reveal overall high recombination rates, a lack of suppressed recombination in centromeres, and significantly lower recombination rates on chromosomes that are known to be accessory. The comparison of the recombination landscapes of the two species reveals a strong correlation of recombination rate at the megabase scale, but little correlation at smaller scales. The recombination landscapes in both pathogen species are dominated by frequent recombination hotspots across the genome including coding regions, suggesting a strong impact of recombination on gene evolution. A significant but small fraction of these hotspots colocalize between the two species, suggesting that hotspot dynamics contribute to the overall pattern of fast evolving recombination in these species. Copyright © 2018 Stukenbrock and Dutheil.

Genetic Recombination

Science.gov (United States)

Whitehouse, H. L. K.

1973-01-01

Discusses the mechanisms of genetic recombination with particular emphasis on the study of the fungus Sordaria brevicollis. The study of recombination is facilitated by the use of mutants of this fungus in which the color of the ascospores is affected. (JR)

Comparative investigation on the efficacy of tulathromycin and florfenicol in the treatment of bronchopneumonia in feedlot calves

Directory of Open Access Journals (Sweden)

Jezdimirović Milanka

2011-01-01

Full Text Available The clinical efficacy of tulathromycin (TU and florfenicol (FL in the treatment of bronchopneumonia (BP caused by Pasteurella multocida which was isolated from nose swabs of diseased calves has been examined. The symptoms of bronchopneumonia (BP were quantified by means of the clinical score (CS with a maximum of 47 points. In the current investigation the average CS in diseased calves was 23.5± 0.15. The clinical efficacy of TU and FL was assessed every day in the first week after the administration of the drugs and was based on the decrease in CS and on microbiological findings on days 7, 28 and 35 after the completion of therapy. Tulathromycin was administered s.c., in the prescribed therapeutic dose (2.5 mg/kg BW, and florfenicol s.c., twice at a 48 h interval, in its respective therapeutic dose (40 mg/kg BW. In spite of the repeated administration of FL, TU was significantly more rapid to decrease the major clinical symptoms in the first four days following the application, in comparison with FL (P<0.05. On the fourth day after the administration, the clinical efficacy of TU in the therapy of BP in calves was 43.4±1.5 %, and of florfenicol 27.2±1.6 %. However, five days after the application of TU and two days after the repeated application of FL the assessed clinical efficacy of the two antibiotics was roughly the same. The average efficacy of TU was 57.1±0.0%, and of florfenicol 58.5±0.0%, both the individual and mean CS in the treated calves was 10 points, due to hyperthermia, which remained the only symptom. Six days after the administration of TU and three days after the repeated application of FL both antibiotics had equal maximum efficacy (100% in the treatment of BP. The clinical efficacy remained unchanged on day seven. The recovery was confirmed by the absence of P. multocida in nose swabs sampled on the seventh day after the initial treatment. However, in 4 calves (21.05 % of the 19 treated Streptococcus alpha haemolyticus

Recombining without Hotspots: A Comprehensive Evolutionary Portrait of Recombination in Two Closely Related Species of Drosophila

Science.gov (United States)

Smukowski Heil, Caiti S.; Ellison, Chris; Dubin, Matthew; Noor, Mohamed A.F.

2015-01-01

Meiotic recombination rate varies across the genome within and between individuals, populations, and species in virtually all taxa studied. In almost every species, this variation takes the form of discrete recombination hotspots, determined in some mammals by a protein called PRDM9. Hotspots and their determinants have a profound effect on the genomic landscape, and share certain features that extend across the tree of life. Drosophila, in contrast, are anomalous in their absence of hotspots, PRDM9, and other species-specific differences in the determination of recombination. To better understand the evolution of meiosis and general patterns of recombination across diverse taxa, we present a truly comprehensive portrait of recombination across time, combining recently published cross-based contemporary recombination estimates from each of two sister species with newly obtained linkage-disequilibrium-based historic estimates of recombination from both of these species. Using Drosophila pseudoobscura and Drosophila miranda as a model system, we compare recombination rate between species at multiple scales, and we suggest that Drosophila replicate the pattern seen in human–chimpanzee in which recombination rate is conserved at broad scales. We also find evidence of a species-wide recombination modifier(s), resulting in both a present and historic genome-wide elevation of recombination rates in D. miranda, and identify broad scale effects on recombination from the presence of an inversion. Finally, we reveal an unprecedented view of the distribution of recombination in D. pseudoobscura, illustrating patterns of linked selection and where recombination is taking place. Overall, by combining these estimation approaches, we highlight key similarities and differences in recombination between Drosophila and other organisms. PMID:26430062

Laser-induced electron--ion recombination used to study enhanced spontaneous recombination during electron cooling

International Nuclear Information System (INIS)

Schramm, U.; Wolf, A.; Schuess ler, T.; Habs, D.; Schwalm, D.; Uwira, O.; Linkemann, J.; Mueller, A.

1997-01-01

Spontaneous recombination of highly charged ions with free electrons in merged velocity matched electron and ion beams has been observed in earlier experiments to occur at rates significantly higher than predicted by theoretical estimates. To study this enhanced spontaneous recombination, laser induced recombination spectra were measured both in velocity matched beams and in beams with well defined relative velocities, corresponding to relative electron-ion detuning energies ranging from 1 meV up to 6.5 meV where the spontaneous recombination enhancement was found to be strongly reduced. Based on a comparison with simplified calculations, the development of the recombination spectra for decreasing detuning energies indicates additional contributions at matched velocities which could be related to the energy distribution of electrons causing the spontaneous recombination rate enhancement

Effects of nuclear mutations for recombination and repair functions and of caffeine on mitochondrial recombination

International Nuclear Information System (INIS)

Fraenkel, A.H.M.

1974-01-01

Studies of both prokaryotic and eukaryotic organisms indicate that pathways governing repair of damage to nuclear DNA caused by x-ray or ultraviolet irradiation overlap with those controlling recombination. Fourteen nuclear mutants of Saccharomyces cerevisiae were tested in order to determine whether these mutant genes affected mitochondrial recombination. None of the mutations studied significantly affected mitochondrial recombination. The nuclear recombination and repair pathways studied do not overlap with the nuclear pathway which controls recombination of mitochondrial DNA. A second set of experiments was designed to test the effect of caffeine on both nuclear and mitochondrial recombination in Saccharomyces cerevisiae. (U.S.)

Immunomodulatory activity of methanolic extract of Morus alba Linn. (mulberry) leaves.

Science.gov (United States)

Bharani, Shendige Eswara Rao; Asad, Mohammed; Dhamanigi, Sunil Samson; Chandrakala, Gowda Kallenahalli

2010-01-01

The leaves of Morus alba Linn. (Family: Moraceae) commonly known as mulberry are mainly used as food for the silkworms and they are sometimes eaten as vegetable or used as cattle fodder in different parts of the world. The effect of Morus alba on the immune system was evaluated by using different experimental models such as carbon clearance test, cyclophosphamide induced neutropenia, neutrophil adhesion test, effect on serum immunoglobulins, mice lethality test and indirect haemagglutination test. Methanolic extract of Morus alba was administered orally at low dose and high dose of 100 mg/kg and 1 g/kg respectively and Ocimum sanctum (100 mg/kg, po) was used as standard drug. Morus alba extract in both doses increased the levels of serum immunoglobulins and prevented the mortality induced by bovine Pasteurella multocida in mice. It also increased the circulating antibody titre in indirect haemagglutination test. On the other hand, it showed significant increase in the phagocytic index in carbon clearance assay, a significant protection against cyclophosphamide induced neutropenia and increased the adhesion of neutrophils in the neutrophil adhesion test. Hence, it was concluded that Morus alba increases both humoral immunity and cell mediated immunity.

How Respiratory Pathogens Contribute to Lamb Mortality in a Poorly Performing Bighorn Sheep ( Ovis canadensis ) Herd.

Science.gov (United States)

Wood, Mary E; Fox, Karen A; Jennings-Gaines, Jessica; Killion, Halcyon J; Amundson, Sierra; Miller, Michael W; Edwards, William H

2017-01-01

We evaluated bighorn sheep ( Ovis canadensis ) ewes and their lambs in captivity to examine the sources and roles of respiratory pathogens causing lamb mortality in a poorly performing herd. After seven consecutive years of observed December recruitments of sheep from the remnant Gribbles Park herd in Colorado, US were captured and transported to the Thorne-Williams Wildlife Research Center in Wyoming in March 2013. Ewes were sampled repeatedly over 16 mo. In April 2014, ewes were separated into individual pens prior to lambing. Upon death, lambs were necropsied and tested for respiratory pathogens. Six lambs developed clinical respiratory disease and one lamb was abandoned. Pathology from an additional six lambs born in 2013 was also evaluated. Mycoplasma ovipneumoniae , leukotoxigenic Mannheimia spp., leukotoxigenic Bibersteinia trehalosi , and Pasteurella multocida all contributed to lamb pneumonia. Histopathology suggested a continuum of disease, with lesions typical of pasteurellosis predominating in younger lambs and lesions typical of mycoplasmosis predominating in older lambs. Mixed pathology was observed in lambs dying between these timeframes. We suspected that all the ewes in our study were persistently infected and chronically shedding the bacteria that contributed to summer lamb mortality.

Recombining without Hotspots: A Comprehensive Evolutionary Portrait of Recombination in Two Closely Related Species of Drosophila.

Science.gov (United States)

Smukowski Heil, Caiti S; Ellison, Chris; Dubin, Matthew; Noor, Mohamed A F

2015-10-01

Meiotic recombination rate varies across the genome within and between individuals, populations, and species in virtually all taxa studied. In almost every species, this variation takes the form of discrete recombination hotspots, determined in some mammals by a protein called PRDM9. Hotspots and their determinants have a profound effect on the genomic landscape, and share certain features that extend across the tree of life. Drosophila, in contrast, are anomalous in their absence of hotspots, PRDM9, and other species-specific differences in the determination of recombination. To better understand the evolution of meiosis and general patterns of recombination across diverse taxa, we present a truly comprehensive portrait of recombination across time, combining recently published cross-based contemporary recombination estimates from each of two sister species with newly obtained linkage-disequilibrium-based historic estimates of recombination from both of these species. Using Drosophila pseudoobscura and Drosophila miranda as a model system, we compare recombination rate between species at multiple scales, and we suggest that Drosophila replicate the pattern seen in human-chimpanzee in which recombination rate is conserved at broad scales. We also find evidence of a species-wide recombination modifier(s), resulting in both a present and historic genome-wide elevation of recombination rates in D. miranda, and identify broad scale effects on recombination from the presence of an inversion. Finally, we reveal an unprecedented view of the distribution of recombination in D. pseudoobscura, illustrating patterns of linked selection and where recombination is taking place. Overall, by combining these estimation approaches, we highlight key similarities and differences in recombination between Drosophila and other organisms. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Therapeutic Recombinant Monoclonal Antibodies

Science.gov (United States)

Bakhtiar, Ray

2012-01-01

During the last two decades, the rapid growth of biotechnology-derived techniques has led to a myriad of therapeutic recombinant monoclonal antibodies with significant clinical benefits. Recombinant monoclonal antibodies can be obtained from a number of natural sources such as animal cell cultures using recombinant DNA engineering. In contrast to…

Recombination every day: abundant recombination in a virus during a single multi-cellular host infection.

Directory of Open Access Journals (Sweden)

Remy Froissart

2005-03-01

Full Text Available Viral recombination can dramatically impact evolution and epidemiology. In viruses, the recombination rate depends on the frequency of genetic exchange between different viral genomes within an infected host cell and on the frequency at which such co-infections occur. While the recombination rate has been recently evaluated in experimentally co-infected cell cultures for several viruses, direct quantification at the most biologically significant level, that of a host infection, is still lacking. This study fills this gap using the cauliflower mosaic virus as a model. We distributed four neutral markers along the viral genome, and co-inoculated host plants with marker-containing and wild-type viruses. The frequency of recombinant genomes was evaluated 21 d post-inoculation. On average, over 50% of viral genomes recovered after a single host infection were recombinants, clearly indicating that recombination is very frequent in this virus. Estimates of the recombination rate show that all regions of the genome are equally affected by this process. Assuming that ten viral replication cycles occurred during our experiment-based on data on the timing of coat protein detection-the per base and replication cycle recombination rate was on the order of 2 x 10(-5 to 4 x 10(-5. This first determination of a virus recombination rate during a single multi-cellular host infection indicates that recombination is very frequent in the everyday life of this virus.

Regulation of Meiotic Recombination

Energy Technology Data Exchange (ETDEWEB)

Gregory p. Copenhaver

2011-11-09

Meiotic recombination results in the heritable rearrangement of DNA, primarily through reciprocal exchange between homologous chromosome or gene conversion. In plants these events are critical for ensuring proper chromosome segregation, facilitating DNA repair and providing a basis for genetic diversity. Understanding this fundamental biological mechanism will directly facilitate trait mapping, conventional plant breeding, and development of genetic engineering techniques that will help support the responsible production and conversion of renewable resources for fuels, chemicals, and the conservation of energy (1-3). Substantial progress has been made in understanding the basal recombination machinery, much of which is conserved in organisms as diverse as yeast, plants and mammals (4, 5). Significantly less is known about the factors that regulate how often and where that basal machinery acts on higher eukaryotic chromosomes. One important mechanism for regulating the frequency and distribution of meiotic recombination is crossover interference - or the ability of one recombination event to influence nearby events. The MUS81 gene is thought to play an important role in regulating the influence of interference on crossing over. The immediate goals of this project are to use reverse genetics to identify mutants in two putative MUS81 homologs in the model plant Arabidopsis thaliana, characterize those mutants and initiate a novel forward genetic screen for additional regulators of meiotic recombination. The long-term goal of the project is to understand how meiotic recombination is regulated in higher eukaryotes with an emphasis on the molecular basis of crossover interference. The ability to monitor recombination in all four meiotic products (tetrad analysis) has been a powerful tool in the arsenal of yeast geneticists. Previously, the qrt mutant of Arabidopsis, which causes the four pollen products of male meiosis to remain attached, was developed as a facile system

Recombination of cluster ions

Science.gov (United States)

Johnsen, Rainer

1993-01-01

Some of our recent work on molecular band emissions from recombination of molecular dimer ions (N4(+) and CO(+) CO) is discussed. Much of the experimental work was done by Y. S. Cao; the results on N4(+) recombination have been published. A brief progress report is given on our ongoing measurements of neutral products of recombination using the flowing-afterglow Langmuir-probe technique in conjunction with laser-induced fluorescence.

In vivo production of recombinant proteins using occluded recombinant AcMNPV-derived baculovirus vectors.

Science.gov (United States)

Guijarro-Pardo, Eva; Gómez-Sebastián, Silvia; Escribano, José M

2017-12-01

Trichoplusia ni insect larvae infected with vectors derived from the Autographa californica multiple nucleopolyhedrovirus (AcMNPV), are an excellent alternative to insect cells cultured in conventional bioreactors to produce recombinant proteins because productivity and cost-efficiency reasons. However, there is still a lot of work to do to reduce the manual procedures commonly required in this production platform that limit its scalability. To increase the scalability of this platform technology, a current bottleneck to be circumvented in the future is the need of injection for the inoculation of larvae with polyhedrin negative baculovirus vectors (Polh-) because of the lack of oral infectivity of these viruses, which are commonly used for production in insect cell cultures. In this work we have developed a straightforward alternative to obtain orally infective vectors derived from AcMNPV and expressing recombinant proteins that can be administered to the insect larvae (Trichoplusia ni) by feeding, formulated in the insect diet. The approach developed was based on the use of a recombinant polyhedrin protein expressed by a recombinant vector (Polh+), able to co-occlude any recombinant Polh- baculovirus vector expressing a recombinant protein. A second alternative was developed by the generation of a dual vector co-expressing the recombinant polyhedrin protein and the foreign gene of interest to obtain the occluded viruses. Additionally, by the incorporation of a reporter gene into the helper Polh+ vector, it was possible the follow-up visualization of the co-occluded viruses infection in insect larvae and will help to homogenize infection conditions. By using these methodologies, the production of recombinant proteins in per os infected larvae, without manual infection procedures, was very similar in yield to that obtained by manual injection of recombinant Polh- AcMNPV-based vectors expressing the same proteins. However, further analyses will be required for a

Recombination pattern reanalysis of some HIV-1 circulating recombination forms suggest the necessity and difficulty of revision.

Directory of Open Access Journals (Sweden)

Lei Jia

Full Text Available Recombination is one of the major mechanisms underlying the generation of HIV-1 variability. Currently 61 circulating recombinant forms of HIV-1 have been identified. With the development of recombination detection techniques and accumulation of HIV-1 reference stains, more accurate mosaic structures of circulating recombinant forms (CRFs, like CRF04 and CRF06, have undergone repeated analysis and upgrades. Such revisions may also be necessary for other CRFs. Unlike previous studies, whose results are based primarily on a single recombination detection program, the current study was based on multiple recombination analysis, which may have produced more impartial results.Representative references of 3 categories of intersubtype recombinants were selected, including BC recombinants (CRF07 and CRF08, BG recombinants (CRF23 and CRF24, and BF recombinants (CRF38 and CRF44. They were reanalyzed in detail using both the jumping profile hidden Markov model and RDP3.The results indicate that revisions and upgrades are very necessary and the entire re-analysis suggested 2 types of revision: (i length of inserted fragments; and (ii number of inserted fragments. The reanalysis also indicated that determination of small regions of about 200 bases or fewer should be performed with more caution.Results indicated that the involvement of multiple recombination detection programs is very necessary. Additionally, results suggested two major challenges, one involving the difficulty of accurately determining the locations of breakpoints and the second involving identification of small regions of about 200 bases or fewer with greater caution. Both indicate the complexity of HIV-1 recombination. The resolution would depend critically on development of a recombination analysis algorithm, accumulation of HIV-1 stains, and a higher sequencing quality. With the changes in recombination pattern, phylogenetic relationships of some CRFs may also change. All these results may

Electron-ion recombination in merged beams

International Nuclear Information System (INIS)

Wolf, A.; Habs, D.; Lampert, A.; Neumann, R.; Schramm, U.; Schuessler, T.; Schwalm, D.

1993-01-01

Detailed studies of recombination processes between electrons and highly charged ions have become possible by recent improvements of merged-beams experiments. We discuss in particular measurements with stored cooled ion beams at the Test Storage Ring (TSR) in Heidelberg. The cross section of dielectronic recombination was measured with high energy resolution for few-electron systems up to the nuclear charge of Cu at a relative energy up to 2.6 keV. At low energy (∼0.1 eV) total recombination rates of several ions were measured and compared with calculated radiative recombination rates. Laser-stimulated recombination of protons and of C 6+ ions was investigated as a function of the photon energy using visible radiation. Both the total recombination rates and the stimulated recombination spectra indicate that in spite of the short interaction time in merged beams, also collisional capture of electrons into weakly bound levels (related to three-body recombination) could be important

Modulation of pulmonary defense mechanisms by acute exposures to nitrogen dioxide. [Staphylococcus aureus; Proteus mirabilis; Pasteurella pneumotropica

Energy Technology Data Exchange (ETDEWEB)

Jakab, G.J.

1987-02-01

The effect of acute exposures to NO/sub 2/ on the antibacterial defenses of the murine lung was assessed following inhalation challenges with Staphylococcus aureus, Proteus mirabilis, and Pasteurella pneumotropica. With S. aureus pulmonary antibacterial defenses were suppressed at NO/sub 2/ levels of 4.0 ppm and greater. Exposure to 10.0 ppm enhanced the intrapulmonary killing of P. mirabilis which correlated with an increase in the phagocytic cell populations lavaged from the lungs; at 20.0 ppm bactericidal activity against P. mirabilis was impaired. Pulmonary antibacterial defenses against P. pneumotropica were impaired at 10.0 ppm which correlated with a decrease in the retrieved phagocytic lung cell population. Reversing the order of treatment (ie., NO/sub 2/ exposure prior to bacterial challenge) raised the threshold concentration for NO/sub 2/-induced impairment of intrapulmonary bacterial killing. With S. aureus the effect was not observed at 5.0 ppm but at 10.0 ppm and with P. mirabilis not at 20.0 ppm but at 30.0 ppm intrapulmonary killing was enhanced. Exposures up to 20.0 ppm of NO/sub 2/ did not effect the physical translocation mechanisms of the lung as quantitated by declines in pulmonary radiotracer activity following aerogenic challenge with /sup 32/P-labeled staphylococci.

Multiple barriers to recombination between divergent HIV-1 variants revealed by a dual-marker recombination assay

DEFF Research Database (Denmark)

Nikolaitchik, Olga A; Galli, Andrea; Moore, Michael D

2011-01-01

Recombination is a major force for generating human immunodeficiency virus type 1 (HIV-1) diversity and produces numerous recombinants circulating in the human population. We previously established a cell-based system using green fluorescent protein gene (gfp) as a reporter to study the mechanisms...... of HIV-1 recombination. We now report an improved system capable of detecting recombination using authentic viral sequences. Frameshift mutations were introduced into the gag gene so that parental viruses do not express full-length Gag; however, recombination can generate a progeny virus that expresses...

Oxygen-hydrogen recombination system

International Nuclear Information System (INIS)

Sato, Shuichiro; Takejima, Masaki.

1981-01-01

Purpose: To avoid reduction in the performance of catalyst used for an oxygen-hydrogen recombiner in the off gas processing system of a nuclear reactor. Constitution: A thermometer is provided for the detection of temperature in an oxygen-hydrogen recombiner. A cooling pipe is provided in the recombiner and cooling medium is introduced externally. The cooling medium may be water or air. In accordance with the detection value from the thermometer, ON-OFF control is carried out for a valve to control the flow rate of the cooling medium thereby rendering the temperature in the recombiner to a predetermined value. This can prevent the catalyst from being exposed to high temperature and avoid the reduction in the performance of the catalyst. (Ikeda, J.)

Hydrogen recombiner development at AECL

International Nuclear Information System (INIS)

Dewit, W.A.; Koroll, G.W.; Loesel Sitar, J.; Graham, W.R.C.

1997-01-01

Catalytic recombiners have been developed at AECL for the purpose of hydrogen removal in post-accident nuclear containment buildings. The recombiners are based on a particular catalyst designed by AECL which has extraordinary resistance to fouling from water and water vapour and a large thermodynamic range of operation. The catalysts were developed, originally, for the purpose of heavy water manufacturing by way of a catalytic exchange process. Application of these catalyst materials in recombiners for containment applications began in the late 1980's. The first application was a passive recombiner, qualified for use in control of radiolytic hydrogen in the headspace of a pool-type experimental reactor of AECL design in 1988. The passive, or natural convection recombiner concept has continued development to commercial stage for application in power reactor containments. This paper reviews the AECL recombiner development, describes the current model and shows results from tests of full-scale recombiners in the Large Scale Vented Combustion Test Facility at AECL-WL. The AECL recombiner is designed for compactness and ease of engineering into containment. The design is a simple, open-ended rectangular enclosure with catalyst elements arranged inside to promote optimum convective flow driven by heat of recombination at the catalyst surface. Self start, as evidenced by catalyst heating and initiation of flow, is achieved in less than 1% hydrogen, with available oxygen, at room temperature and 100% relative humidity. This low temperature start-up in condensing atmospheres is viewed as the most challenging condition for wet-proofing effectiveness. Cold start-up is a vital performance requirement in containments, such as CANDU, where engineered air-cooling systems are operating and where long-term hydrogen control is required, after containment atmospheres have cooled. Once started, the removal capacity scales linearly with the inlet cross-section area and the partial

On the relict recombination lines

International Nuclear Information System (INIS)

Bershtejn, I.N.; Bernshtejn, D.N.; Dubrovich, V.K.

1977-01-01

Accurate numerical calculation of intensities and profiles of hydrogen recombination lines of cosmological origin is made. Relie radiation distortions stipulated by recombination quantum release at the irrevocable recombination are investigated. Mean number calculation is given for guantums educing for one irrevocably-lost electron. The account is taken of the educed quantums interraction with matter. The main quantum-matter interrraction mechanisms are considered: electronic blow broadening; free-free, free-bound, bound-bound absorptions Recombination dynamics is investigated depending on hydrogen density and total density of all the matter kinds in the Universe

Late replicating domains are highly recombining in females but have low male recombination rates: implications for isochore evolution.

Directory of Open Access Journals (Sweden)

Catherine J Pink

Full Text Available In mammals sequences that are either late replicating or highly recombining have high rates of evolution at putatively neutral sites. As early replicating domains and highly recombining domains both tend to be GC rich we a priori expect these two variables to covary. If so, the relative contribution of either of these variables to the local neutral substitution rate might have been wrongly estimated owing to covariance with the other. Against our expectations, we find that sex-averaged recombination rates show little or no correlation with replication timing, suggesting that they are independent determinants of substitution rates. However, this result masks significant sex-specific complexity: late replicating domains tend to have high recombination rates in females but low recombination rates in males. That these trends are antagonistic explains why sex-averaged recombination is not correlated with replication timing. This unexpected result has several important implications. First, although both male and female recombination rates covary significantly with intronic substitution rates, the magnitude of this correlation is moderately underestimated for male recombination and slightly overestimated for female recombination, owing to covariance with replicating timing. Second, the result could explain why male recombination is strongly correlated with GC content but female recombination is not. If to explain the correlation between GC content and replication timing we suppose that late replication forces reduced GC content, then GC promotion by biased gene conversion during female recombination is partly countered by the antagonistic effect of later replicating sequence tending increase AT content. Indeed, the strength of the correlation between female recombination rate and local GC content is more than doubled by control for replication timing. Our results underpin the need to consider sex-specific recombination rates and potential covariates in

Auger recombination in sodium iodide

Science.gov (United States)

McAllister, Andrew; Kioupakis, Emmanouil; Åberg, Daniel; Schleife, André

2014-03-01

Scintillators are an important tool used to detect high energy radiation - both in the interest of national security and in medicine. However, scintillator detectors currently suffer from lower energy resolutions than expected from basic counting statistics. This has been attributed to non-proportional light yield compared to incoming radiation, but the specific mechanism for this non-proportionality has not been identified. Auger recombination is a non-radiative process that could be contributing to the non-proportionality of scintillating materials. Auger recombination comes in two types - direct and phonon-assisted. We have used first-principles calculations to study Auger recombination in sodium iodide, a well characterized scintillating material. Our findings indicate that phonon-assisted Auger recombination is stronger in sodium iodide than direct Auger recombination. Computational resources provided by LLNL and NERSC. Funding provided by NA-22.

Regulation of homologous recombination in eukaryotes

OpenAIRE

Heyer, Wolf-Dietrich; Ehmsen, Kirk T.; Liu, Jie

2010-01-01

Homologous recombination is required for accurate chromosome segregation during the first meiotic division and constitutes a key repair and tolerance pathway for complex DNA damage including DNA double-stranded breaks, interstrand crosslinks, and DNA gaps. In addition, recombination and replication are inextricably linked, as recombination recovers stalled and broken replication forks enabling the evolution of larger genomes/replicons. Defects in recombination lead to genomic instability and ...

Recombination coefficients in extrinsic n-InSb

International Nuclear Information System (INIS)

Schneider, W.; Groh, H.; Huebner, K.

1976-01-01

The bulk recombination coefficients for linear recombination via recombination centers as well as for direct recombination have been determined measuring the conductivity decay after two-photon absorption with a CO 2 laser. The Suhl effect was applied to measure the surface recombination velocity. The corresponding literature is discussed and compared with our results. We conclude that two different kinds of recombination centers are possible in n-InSb, with energy levels (0.1-0.12)eV above the valence band, or (0.14-0.2)eV respectively. (orig.) [de

Electron-ion recombination rates for merged-beams experiments

International Nuclear Information System (INIS)

Pajek, M.

1994-01-01

Energy dependence of the electron-ion recombination rates are studied for different recombination processes (radiative recombination, three-body recombination, dissociative recombination) for Maxwellian relative velocity distribution of arbitrary asymmetry. The results are discussed in context of the electron-ion merged beams experiments in cooling ion storage rings. The question of indication of a possible contribution of the three-body recombination to the measured recombination rates versus relative energy is particularly addressed. Its influence on the electron beam temperature derived from the energy dependence of recombination rate is discussed

Electron-ion recombination at low energy

International Nuclear Information System (INIS)

Andersen, L.H.

1993-01-01

The work is based on results obtained with a merged-beams experiment. A beam of electronics with a well characterized density and energy distribution was merged with a fast, monoenergetic ion beam. Results have been obtained for radiative recombination and dielectronic recombination at low relative energies (0 to ∼70eV). The obtained energy resolution was improved by about a factor of 30. High vacuum technology was used to suppress interactions with electrons from the environments. The velocity distribution of the electron beam was determined. State-selective dielectronic-recombination measurements were performable. Recombination processes were studied. The theoretical background for radiative recombination and Kramers' theory are reviewed. The quantum mechanical result and its relation to the semiclassical theory is discussed. Radiative recombination was also measured with several different non-bare ions, and the applicability of the semiclassical theory to non-bare ions was investigated. The use of an effective charge is discussed. For dielectronic recombination, the standard theoretical approach in the isolated resonance and independent-processes approximation is debated. The applicability of this method was tested. The theory was able to reproduce most of the experimental data except when the recombination process was sensitive to couplings between different electronic configurations. The influence of external perturbing electrostatic fields is discussed. (AB) (31 refs.)

Recombinant Innovation and Endogenous Transitions

OpenAIRE

Koen Frenken; Luis R. Izquierdo; Paolo Zeppini

2012-01-01

We propose a model of technological transitions based on two different types of innovations. Branching innovations refer to technological improvements along a particular path, while recombinant innovations represent fusions of multiple paths. Recombinant innovations create “short-cuts” which reduce switching costs allowing agents to escape a technological lock-in. As a result, recombinant innovations speed up technological progress allowing transitions that are impossible with only branching ...

Interface recombination influence on carrier transport

International Nuclear Information System (INIS)

Konin, A

2013-01-01

A theory of interface recombination in the semiconductor–semiconductor junction is developed. The interface recombination rate dependence on the nonequilibrium carrier densities is derived on the basis of a model in which the interface recombination occurs through the mechanism of trapping. The general relation between the interface recombination parameters at small carrier density deviation from the equilibrium ones is obtained. The validity of this relation is proved considering the generation of the Hall electric field in the extrinsic semiconductor sample. The anomalous Hall electromotive force in a weak magnetic field was investigated and interpreted by means of a new interface recombination model. The experimental data corroborate the developed theory. (paper)

Caenorhabditis briggsae recombinant inbred line genotypes reveal inter-strain incompatibility and the evolution of recombination.

Directory of Open Access Journals (Sweden)

Joseph A Ross

2011-07-01

Full Text Available The nematode Caenorhabditis briggsae is an emerging model organism that allows evolutionary comparisons with C. elegans and exploration of its own unique biological attributes. To produce a high-resolution C. briggsae recombination map, recombinant inbred lines were generated from reciprocal crosses between two strains and genotyped at over 1,000 loci. A second set of recombinant inbred lines involving a third strain was also genotyped at lower resolution. The resulting recombination maps exhibit discrete domains of high and low recombination, as in C. elegans, indicating these are a general feature of Caenorhabditis species. The proportion of a chromosome's physical size occupied by the central, low-recombination domain is highly correlated between species. However, the C. briggsae intra-species comparison reveals striking variation in the distribution of recombination between domains. Hybrid lines made with the more divergent pair of strains also exhibit pervasive marker transmission ratio distortion, evidence of selection acting on hybrid genotypes. The strongest effect, on chromosome III, is explained by a developmental delay phenotype exhibited by some hybrid F2 animals. In addition, on chromosomes IV and V, cross direction-specific biases towards one parental genotype suggest the existence of cytonuclear epistatic interactions. These interactions are discussed in relation to surprising mitochondrial genome polymorphism in C. briggsae, evidence that the two strains diverged in allopatry, the potential for local adaptation, and the evolution of Dobzhansky-Muller incompatibilities. The genetic and genomic resources resulting from this work will support future efforts to understand inter-strain divergence as well as facilitate studies of gene function, natural variation, and the evolution of recombination in Caenorhabditis nematodes.

Molecular requirements for radiation-activated recombination

International Nuclear Information System (INIS)

Stevens, Craig W.; Zeng Ming; Stamato, Thomas; Cerniglia, George

1997-01-01

Purpose/Objective: The major stumbling block to successful gene therapy today is poor gene transfer. We hypothesized that ionizing radiation might activate cellular recombination, and so improve stable gene transfer. We further hypothesized that known DNA-damage-repair proteins might also be important in radiation-activated recombination. Materials and Methods: The effect of irradiation on stable gene transfer efficiency was determined in human (A549 and 39F) and rodent (NIH/3T3) cell lines. Continuous low dose rate and multiple radiation fractions were also tested. Nuclear extracts were made and the effect of irradiation on inter-plasmid recombination/ligation determined. Multiple DNA damage-repair deficient cell lines were tested for radiation-activated recombination. Results: A significant radiation dose-dependent improvement in stable plasmid transfection (by as much as 1300 fold) is demonstrated in neoplastic and primary cells. An improvement in transient plasmid transfection is also seen, with as much as 85% of cells transiently expressing b-galactosidase (20-50 fold improvement). Stable transfection is only improved for linearized or nicked plasmids. Cells have improved gene transfer for at least 96 hours after irradiation. Both fractionated and continuous low dose rate irradiation are effective at improving stable gene transfer in mammalian cells, thus making relatively high radiation dose delivery clinically feasible. Inter-plasmid recombination is radiation dose dependent in nuclear extract assays, and the type of overhang (3', 5' or blunt end) significantly affects recombination efficiency and the type of product. The most common end-joining activity involves filling-in of the overhang followed by blunt end ligation. Adenovirus is a linear, double stranded DNA virus. We demonstrate that adenoviral infection efficiency is increased by irradiation. The duration of transgene expression is lengthened because the virus integrates with high efficiency (∼10

Recombinant pinoresinol/lariciresinol reductase, recombinant dirigent protein, and methods of use

Science.gov (United States)

Lewis, Norman G.; Davin, Laurence B.; Dinkova-Kostova, Albena T.; Fujita, Masayuki; Gang, David R.; Sarkanen, Simo; Ford, Joshua D.

2001-04-03

Dirigent proteins and pinoresinol/lariciresinol reductases have been isolated, together with cDNAs encoding dirigent proteins and pinoresinol/lariciresinol reductases. Accordingly, isolated DNA sequences are provided which code for the expression of dirigent proteins and pinoresinol/lariciresinol reductases. In other aspects, replicable recombinant cloning vehicles are provided which code for dirigent proteins or pinoresinol/lariciresinol reductases or for a base sequence sufficiently complementary to at least a portion of dirigent protein or pinoresinol/lariciresinol reductase DNA or RNA to enable hybridization therewith. In yet other aspects, modified host cells are provided that have been transformed, transfected, infected and/or injected with a recombinant cloning vehicle and/or DNA sequence encoding dirigent protein or pinoresinol/lariciresinol reductase. Thus, systems and methods are provided for the recombinant expression of dirigent proteins and/or pinoresinol/lariciresinol reductases.

Population inversion in recombining hydrogen plasma

International Nuclear Information System (INIS)

Furukane, Utaro; Yokota, Toshiaki; Oda, Toshiatsu.

1978-11-01

The collisional-radiative model is applied to a recombining hydrogen plasma in order to investigate the plasma condition in which the population inversion between the energy levels of hydrogen can be generated. The population inversion is expected in a plasma where the three body recombination has a large contribution to the recombining processes and the effective recombination rate is beyond a certain value for a given electron density and temperature. Calculated results are presented in figures and tables. (author)

Consequences of recombination on traditional phylogenetic analysis

DEFF Research Database (Denmark)

Schierup, M H; Hein, J

2000-01-01

We investigate the shape of a phylogenetic tree reconstructed from sequences evolving under the coalescent with recombination. The motivation is that evolutionary inferences are often made from phylogenetic trees reconstructed from population data even though recombination may well occur (mt......DNA or viral sequences) or does occur (nuclear sequences). We investigate the size and direction of biases when a single tree is reconstructed ignoring recombination. Standard software (PHYLIP) was used to construct the best phylogenetic tree from sequences simulated under the coalescent with recombination....... With recombination present, the length of terminal branches and the total branch length are larger, and the time to the most recent common ancestor smaller, than for a tree reconstructed from sequences evolving with no recombination. The effects are pronounced even for small levels of recombination that may...

The role of lipooligosaccharide phosphorylcholine in colonization and pathogenesis of Histophilus somni in cattle

Directory of Open Access Journals (Sweden)

Elswaifi Shaadi F

2012-06-01

Full Text Available Abstract Histophilus somni is a Gram-negative bacterium and member of the Pasteurellaceae that is responsible for respiratory disease and other systemic infections in cattle. One of the bacterium’s virulence factors is antigenic phase variation of its lipooligosaccharide (LOS. LOS antigenic variation may occur through variation in composition or structure of glycoses or their substitutions, such as phosphorylcholine (ChoP. However, the role of ChoP in the pathogenesis of H. somni disease has not been established. In Haemophilus influenzae ChoP on the LOS binds to platelet activating factor on epithelial cells, promoting bacterial colonization of the host upper respiratory tract. However, ChoP is not expressed in the blood as it also binds C-reactive protein, resulting in complement activation and killing of the bacteria. In order to simulate the susceptibility of calves with suppressed immunity due to stress or previous infection, calves were challenged with bovine herpes virus-1 or dexamethazone 3 days prior to challenge with H. somni. Following challenge, expression of ChoP on the LOS of 2 different H. somni strains was associated with colonization of the upper respiratory tract. In contrast, lack of ChoP expression was associated with bacteria recovered from systemic sites. Histopathology of cardiac tissue from myocarditis revealed lesions containing bacterial clusters that appeared similar to a biofilm. Furthermore, some respiratory cultures contained substantial numbers of Pasteurella multocida, which were not present on preculture screens. Subsequent biofilm experiments have shown that H. somni and P. multocida grow equally well together in a biofilm, suggesting a commensal relationship may exist between the two species. Our results also showed that ChoP contributed to, but was not required for, adhesion to respiratory epithelial cells. In conclusion, expression of ChoP on H. somni LOS contributed to colonization of the bacteria to the

Potential probiotic attributes of a new strain of Bacillus coagulans CGMCC 9951 isolated from healthy piglet feces.

Science.gov (United States)

Gu, Shao-Bin; Zhao, Li-Na; Wu, Ying; Li, Shi-Chang; Sun, Jian-Rui; Huang, Jing-Fang; Li, Dan-Dan

2015-06-01

A new strain of Bacillus coagulans CGMCC 9551, which has a broad range of antibacterial activities against six main pathogenic bacteria including Escherichia coli O8, Staphylococcus aureus, Salmonella enterica subsp. enterica serovar enteritidis, Streptococcus suis, Listeria monocytogenes and Pasteurella multocida, was isolated from healthy piglet feces. In adhesion assay, the isolate exhibited a stronger adhesion to pig intestinal mucus than that of B. subtilis JT143 and L. acidophilus LY24 respectively isolated from BioPlus(®)2B and FloraFIT(®) Probiotics (P coagulans CGMCC 9551 was reduced by only 20% at 4 h exposure under 0.9% w/v bile salt. The strain was fully resistant to pH 2 for 2 h with 90.1 ± 3.5% survival and susceptible to 15 antibiotics commonly used in veterinary medicine. Additionally, the bacteria showed amylase, protease and cellulase activities. The safety assessment demonstrated the lack of toxicity potential in B. coagulans CGMCC 9551 by ligated rabbit ileal loop assay, acute and subchronic toxicity test. These results implied that that the new strain of B. coagulans CGMCC 9951 isolated from healthy piglet feces has promising probiotic characteristics and offers desirable opportunities for its successful commercialization as one excellent candidate probiotic.

Whole Genome Sequence Analysis of Pig Respiratory Bacterial Pathogens with Elevated Minimum Inhibitory Concentrations for Macrolides.

Science.gov (United States)

Dayao, Denise Ann Estarez; Seddon, Jennifer M; Gibson, Justine S; Blackall, Patrick J; Turni, Conny

2016-10-01

Macrolides are often used to treat and control bacterial pathogens causing respiratory disease in pigs. This study analyzed the whole genome sequences of one clinical isolate of Actinobacillus pleuropneumoniae, Haemophilus parasuis, Pasteurella multocida, and Bordetella bronchiseptica, all isolated from Australian pigs to identify the mechanism underlying the elevated minimum inhibitory concentrations (MICs) for erythromycin, tilmicosin, or tulathromycin. The H. parasuis assembled genome had a nucleotide transition at position 2059 (A to G) in the six copies of the 23S rRNA gene. This mutation has previously been associated with macrolide resistance but this is the first reported mechanism associated with elevated macrolide MICs in H. parasuis. There was no known macrolide resistance mechanism identified in the other three bacterial genomes. However, strA and sul2, aminoglycoside and sulfonamide resistance genes, respectively, were detected in one contiguous sequence (contig 1) of A. pleuropneumoniae assembled genome. This contig was identical to plasmids previously identified in Pasteurellaceae. This study has provided one possible explanation of elevated MICs to macrolides in H. parasuis. Further studies are necessary to clarify the mechanism causing the unexplained macrolide resistance in other Australian pig respiratory pathogens including the role of efflux systems, which were detected in all analyzed genomes.

Occurrence and severity of lung lesions in slaughter pigs vaccinated against Mycoplasma hyopneumoniae with different strategies.

Science.gov (United States)

Hillen, Sonja; von Berg, Stephan; Köhler, Kernt; Reinacher, Manfred; Willems, Hermann; Reiner, Gerald

2014-03-01

Different vaccination strategies against Mycoplasma hyopneumoniae have been adopted worldwide. Reports from the field indicate varying levels of protection among currently available vaccines. The goal of the present study was to compare the efficacies of three widespread commercial vaccination strategies against M. hyopneumoniae under field conditions. 20 farms were included. 14 farms used different single dose vaccines (vaccine 1 [V1], 8 herds; vaccine 2 [V2], 6 herds); another 6 farms (V3) used a two dose vaccination strategy. Gross lesions of 854 lungs and histopathology from 140 lungs were quantified, and a quantitative PCR was applied to detect M. hyopneumoniae and porcine circovirus 2 (PCV2) DNA in lung tissue (n=140). In addition, porcine reproductive and respiratory disease virus (PRRSV), swine influenza virus (SIV), Actinobacillus pleuropneumoniae, Haemophilus parasuis and Pasteurella multocida were tested by qualitative PCR. 53% of lungs were positive for M. hyopneumoniae. 55.9% of lungs showed macroscopic enzootic pneumonia (EP)-like lesions. Lung lesion scores (Phyopneumoniae-loads (Phyopneumoniae indicating that the applied diagnostic tools are valuable in confirming the prevalence and severity of M. hyopneumoniae infections. Comparing different vaccination strategies against M. hyopneumoniae indicates varying levels of protection. M. hyopneumoniae is still a major problem despite the widely applied vaccination. Copyright © 2014 Elsevier B.V. All rights reserved.

Density dependence of dielectronic recombination in selenium

International Nuclear Information System (INIS)

Hagelstein, P.L.; Rosen, M.D.; Jacobs, V.L.

1986-01-01

Dielectronic recombination has been found to be the dominant recombination process in the determination of the ionization balance of selenium near the Ne-like sequence under conditions relevant to the exploding-foil EUV laser plasmas. The dielectronic recombination process tends to populate excited levels, and these levels in turn are more susceptible to subsequent excitation and ionization than are the ground-state ions. If one defines an effective recombination rate which includes, in addition to the primary recombination, the subsequent excitation and ionization of the additional excited-state population due to the primary recombination, then this effective recombination rate can be density-sensitive at relatively low electron density. We present results for this effective dielectronic recombination rate at an electron density of 3 x 10/sup 20/ electrons/cm 3 for recombination from Ne-like to Na-like selenium and from F-like to Ne-like selenium. In the former case, the effective recombination rate coefficient is found to be 1.8 x 10/sup -11/ cm 3 /sec at 1.0 keV, which is to be compared with the zero-density value of 2.8 x 10/sup -11/ cm 3 /sec. In the latter case (F-like to Ne-like), the effective recombination rate coefficient is found to be 1.3 x 10/sup -11/ cm 3 /sec, which is substantially reduced from the zero-density result of 3.3 x 10/sup -11/ cm 3 /sec. We have examined the effects of dielectronic recombination on the laser gain of the dominant Ne-like 3p-3s transitions and have compared our results with those presented by Whitten et al. [Phys. Rev. A 33, 2171 (1986)

SequenceLDhot: detecting recombination hotspots.

Science.gov (United States)

Fearnhead, Paul

2006-12-15

There is much local variation in recombination rates across the human genome--with the majority of recombination occurring in recombination hotspots--short regions of around approximately 2 kb in length that have much higher recombination rates than neighbouring regions. Knowledge of this local variation is important, e.g. in the design and analysis of association studies for disease genes. Population genetic data, such as that generated by the HapMap project, can be used to infer the location of these hotspots. We present a new, efficient and powerful method for detecting recombination hotspots from population data. We compare our method with four current methods for detecting hotspots. It is orders of magnitude quicker, and has greater power, than two related approaches. It appears to be more powerful than HotspotFisher, though less accurate at inferring the precise positions of the hotspot. It was also more powerful than LDhot in some situations: particularly for weaker hotspots (10-40 times the background rate) when SNP density is lower (maths.lancs.ac.uk/~fearnhea/Hotspot.

Experimental evolution across different thermal regimes yields genetic divergence in recombination fraction but no divergence in temperature associated plastic recombination.

Science.gov (United States)

Kohl, Kathryn P; Singh, Nadia D

2018-04-01

Phenotypic plasticity is pervasive in nature. One mechanism underlying the evolution and maintenance of such plasticity is environmental heterogeneity. Indeed, theory indicates that both spatial and temporal variation in the environment should favor the evolution of phenotypic plasticity under a variety of conditions. Cyclical environmental conditions have also been shown to yield evolved increases in recombination frequency. Here, we use a panel of replicated experimental evolution populations of D. melanogaster to test whether variable environments favor enhanced plasticity in recombination rate and/or increased recombination rate in response to temperature. In contrast to expectation, we find no evidence for either enhanced plasticity in recombination or increased rates of recombination in the variable environment lines. Our data confirm a role of temperature in mediating recombination fraction in D. melanogaster, and indicate that recombination is genetically and plastically depressed under lower temperatures. Our data further suggest that the genetic architectures underlying plastic recombination and population-level variation in recombination rate are likely to be distinct. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Pasteurella pneumotropica evades the human complement system by acquisition of the complement regulators factor H and C4BP.

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Alfredo Sahagún-Ruiz

Full Text Available Pasteurella pneumotropica is an opportunist Gram negative bacterium responsible for rodent pasteurellosis that affects upper respiratory, reproductive and digestive tracts of mammals. In animal care facilities the presence of P. pneumotropica causes severe to lethal infection in immunodeficient mice, being also a potential source for human contamination. Indeed, occupational exposure is one of the main causes of human infection by P. pneumotropica. The clinical presentation of the disease includes subcutaneous abscesses, respiratory tract colonization and systemic infections. Given the ability of P. pneumotropica to fully disseminate in the organism, it is quite relevant to study the role of the complement system to control the infection as well as the possible evasion mechanisms involved in bacterial survival. Here, we show for the first time that P. pneumotropica is able to survive the bactericidal activity of the human complement system. We observed that host regulatory complement C4BP and Factor H bind to the surface of P. pneumotropica, controlling the activation pathways regulating the formation and maintenance of C3-convertases. These results show that P. pneumotropica has evolved mechanisms to evade the human complement system that may increase the efficiency by which this pathogen is able to gain access to and colonize inner tissues where it may cause severe infections.

The extent and importance of intragenic recombination

Directory of Open Access Journals (Sweden)

de Silva Eric

2004-11-01

Full Text Available Abstract We have studied the recombination rate behaviour of a set of 140 genes which were investigated for their potential importance in inflammatory disease. Each gene was extensively sequenced in 24 individuals of African descent and 23 individuals of European descent, and the recombination process was studied separately in the two population samples. The results obtained from the two populations were highly correlated, suggesting that demographic bias does not affect our population genetic estimation procedure. We found evidence that levels of recombination correlate with levels of nucleotide diversity. High marker density allowed us to study recombination rate variation on a very fine spatial scale. We found that about 40 per cent of genes showed evidence of uniform recombination, while approximately 12 per cent of genes carried distinct signatures of recombination hotspots. On studying the locations of these hotspots, we found that they are not always confined to introns but can also stretch across exons. An investigation of the protein products of these genes suggested that recombination hotspots can sometimes separate exons belonging to different protein domains; however, this occurs much less frequently than might be expected based on evolutionary studies into the origins of recombination. This suggests that evolutionary analysis of the recombination process is greatly aided by considering nucleotide sequences and protein products jointly.

Recombination epoch revisited

International Nuclear Information System (INIS)

Krolik, J.H.

1989-01-01

Previous studies of cosmological recombination have shown that this process produces as a by-product a highly superthermal population of Ly-alpha photons which retard completion of recombination. Cosmological redshifting was thought to determine the frequency distribution of the photons, while two-photon decay of hydrogen's 2s state was thought to control their numbers. It is shown here that frequency diffusion due to photon scattering dominate the cosmological redshift in the frequency range near line center which fixes the ratio of ground state to excited state population, while incoherent scattering into the far-red damping wing effectively destroys Ly-alpha photons as a rate which is competitive with two-photon decay. The former effect tends to hold back recombination, while the latter tends to accelerate it; the net results depends on cosmological parameters, particularly the combination Omega(b) h/sq rt (2q0), where Omega(b) is the fraction of the critical density provided by baryons. 18 references

Recombination of Globally Circulating Varicella-Zoster Virus

Science.gov (United States)

Depledge, Daniel P.; Kundu, Samit; Atkinson, Claire; Brown, Julianne; Haque, Tanzina; Hussaini, Yusuf; MacMahon, Eithne; Molyneaux, Pamela; Papaevangelou, Vassiliki; Sengupta, Nitu; Koay, Evelyn S. C.; Tang, Julian W.; Underhill, Gillian S.; Grahn, Anna; Studahl, Marie; Breuer, Judith; Bergström, Tomas

2015-01-01

ABSTRACT Varicella-zoster virus (VZV) is a human herpesvirus, which during primary infection typically causes varicella (chicken pox) and establishes lifelong latency in sensory and autonomic ganglia. Later in life, the virus may reactivate to cause herpes zoster (HZ; also known as shingles). To prevent these diseases, a live-attenuated heterogeneous vaccine preparation, vOka, is used routinely in many countries worldwide. Recent studies of another alphaherpesvirus, infectious laryngotracheitis virus, demonstrate that live-attenuated vaccine strains can recombine in vivo, creating virulent progeny. These findings raised concerns about using attenuated herpesvirus vaccines under conditions that favor recombination. To investigate whether VZV may undergo recombination, which is a prerequisite for VZV vaccination to create such conditions, we here analyzed 115 complete VZV genomes. Our results demonstrate that recombination occurs frequently for VZV. It thus seems that VZV is fully capable of recombination if given the opportunity, which may have important implications for continued VZV vaccination. Although no interclade vaccine-wild-type recombinant strains were found, intraclade recombinants were frequently detected in clade 2, which harbors the vaccine strains, suggesting that the vaccine strains have already been involved in recombination events, either in vivo or in vitro during passages in cell culture. Finally, previous partial and complete genomic studies have described strains that do not cluster phylogenetically to any of the five established clades. The additional VZV strains sequenced here, in combination with those previously published, have enabled us to formally define a novel sixth VZV clade. IMPORTANCE Although genetic recombination has been demonstrated to frequently occur for other human alphaherpesviruses, herpes simplex viruses 1 and 2, only a few ancient and isolated recent recombination events have hitherto been demonstrated for VZV. In the

BIOTECHNOLOGY OF RECOMBINANT HORMONES IN DOPING

Directory of Open Access Journals (Sweden)

Biljana Vitošević

2011-09-01

Full Text Available Recombinant DNA technology has allowed rapid progress in creating biosynthetic gene products for the treatment of many diseases. In this way it can produce large amounts of hormone, which is intended for the treatment of many pathological conditions. Recombinant hormones that are commonly used are insulin, growth hormone and erythropoietin. Precisely because of the availability of these recombinant hormones, it started their abuse by athletes. Experiments in animal models confirmed the potential effects of some of these hormones in increasing physical abilities, which attracted the attention of athletes who push the limits of their competitive capability by such manipulation. The risks of the use of recombinant hormones in doping include serious consequences for the health of athletes. Methods of detection of endogenous hormones from recombined based on the use of a monoclonal antibodies, capillary zone electrophoresis and protein biomarkers

Delayed recombination and cosmic parameters

International Nuclear Information System (INIS)

Galli, Silvia; Melchiorri, Alessandro; Bean, Rachel; Silk, Joseph

2008-01-01

Current cosmological constraints from cosmic microwave background anisotropies are typically derived assuming a standard recombination scheme, however additional resonance and ionizing radiation sources can delay recombination, altering the cosmic ionization history and the cosmological inferences drawn from the cosmic microwave background data. We show that for recent observations of the cosmic microwave background anisotropy, from the Wilkinson microwave anisotropy probe satellite mission (WMAP) 5-year survey and from the arcminute cosmology bolometer array receiver experiment, additional resonance radiation is nearly degenerate with variations in the spectral index, n s , and has a marked effect on uncertainties in constraints on the Hubble constant, age of the universe, curvature and the upper bound on the neutrino mass. When a modified recombination scheme is considered, the redshift of recombination is constrained to z * =1078±11, with uncertainties in the measurement weaker by 1 order of magnitude than those obtained under the assumption of standard recombination while constraints on the shift parameter are shifted by 1σ to R=1.734±0.028. From the WMAP5 data we obtain the following constraints on the resonance and ionization sources parameters: ε α i <0.058 at 95% c.l.. Although delayed recombination limits the precision of parameter estimation from the WMAP satellite, we demonstrate that this should not be the case for future, smaller angular scales measurements, such as those by the Planck satellite mission.

Meiotic recombination in human oocytes.

Directory of Open Access Journals (Sweden)

Edith Y Cheng

2009-09-01

Full Text Available Studies of human trisomies indicate a remarkable relationship between abnormal meiotic recombination and subsequent nondisjunction at maternal meiosis I or II. Specifically, failure to recombine or recombination events located either too near to or too far from the centromere have been linked to the origin of human trisomies. It should be possible to identify these abnormal crossover configurations by using immunofluorescence methodology to directly examine the meiotic recombination process in the human female. Accordingly, we initiated studies of crossover-associated proteins (e.g., MLH1 in human fetal oocytes to analyze their number and distribution on nondisjunction-prone human chromosomes and, more generally, to characterize genome-wide levels of recombination in the human female. Our analyses indicate that the number of MLH1 foci is lower than predicted from genetic linkage analysis, but its localization pattern conforms to that expected for a crossover-associated protein. In studies of individual chromosomes, our observations provide evidence for the presence of "vulnerable" crossover configurations in the fetal oocyte, consistent with the idea that these are subsequently translated into nondisjunctional events in the adult oocyte.

Electron - ion recombination processes - an overview

International Nuclear Information System (INIS)

Hahn, Yukap

1997-01-01

Extensive theoretical and experimental studies have been carried out for the past 20 years on electron - ion recombination processes, as they are applied to the analysis of astrophysical and laboratory plasmas. We review the basic understanding gained through these efforts, with emphasis on some of the more recent progress made in recombination theory as the recombining system is affected by time-dependent electric fields and plasma particles at low temperature. Together with collisional ionization and excitation processes, recombination is important in determining ionization balance and excited-state population in non-equilibrium plasmas. The radiation emitted by plasmas is usually the principal medium with which to study the plasma condition, as it is produced mainly during the recombination and decay of excited states of ions inside the plasma. This is especially true when the plasma under study is not readily accessible by direct probes, as in astrophysical plasmas. Moreover, external probes may sometimes cause undesirable disturbances of the plasma. Electron-ion recombination proceeds in several different modes. The direct modes include three-body recombination (TBR) and one-step radiative recombination (RR), all to the ground- and singly-excited states of the target ions. By contrast, the indirect resonant mode is a two-step dielectronic recombination (DR), which proceeds first with the formation of doubly-excited states by radiationless excitation/capture. The resonant states thus formed may relax by autoionization and/or radiative cascades. For more exotic modes of recombination, we consider off-shell dielectronic recombination (radiative DR = RDR), in which an electron capture is accompanied by simultaneous radiative emission and excitation of the target ion. Some discussion on attachment of electrons to neutral atoms, resulting in the formation of negative ions, is also given. When resonance states involve one or more electrons in high Rydberg states

Controlled Release from Recombinant Polymers

Science.gov (United States)

Price, Robert; Poursaid, Azadeh; Ghandehari, Hamidreza

2014-01-01

Recombinant polymers provide a high degree of molecular definition for correlating structure with function in controlled release. The wide array of amino acids available as building blocks for these materials lend many advantages including biorecognition, biodegradability, potential biocompatibility, and control over mechanical properties among other attributes. Genetic engineering and DNA manipulation techniques enable the optimization of structure for precise control over spatial and temporal release. Unlike the majority of chemical synthetic strategies used, recombinant DNA technology has allowed for the production of monodisperse polymers with specifically defined sequences. Several classes of recombinant polymers have been used for controlled drug delivery. These include, but are not limited to, elastin-like, silk-like, and silk-elastinlike proteins, as well as emerging cationic polymers for gene delivery. In this article, progress and prospects of recombinant polymers used in controlled release will be reviewed. PMID:24956486

Live recombinant BHV/BRSV vaccine

NARCIS (Netherlands)

Keil, G.M.; Rijsewijk, F.A.M.

1998-01-01

The present invention refers to synthetic Bovine Respiratory Syncytium virus genes. Also the invention relates to live attenuated Bovine Herpesvirus recombinants carrying such synthetic genes. Furthermore, the invention relates to vaccines based on these live attenuated recombinants, for the

First-principles study of Frenkel pair recombination in tungsten

International Nuclear Information System (INIS)

Qin, Shi-Yao; Jin, Shuo; Li, Yu-Hao; Zhou, Hong-Bo; Zhang, Ying; Lu, Guang-Hong

2017-01-01

The recombination of one Frenkel pair in tungsten has been investigated through first-principles simulation. Two different recombination types have been identified: instantaneous and thermally activated. The small recombination barriers for thermally activated recombination cases indicate that recombination can occur easily with a slightly increased temperature. For both of the two recombination types, recombination occurs through the self-interstitial atom moving towards the vacancy. The recombination process can be direct or through replacement sequences, depending on the vertical distance between the vacancy and the 〈1 1 1〉 line of self-interstitial atom pair.

Containment air circulation for optimal hydrogen recombination

International Nuclear Information System (INIS)

Spinks, N.; Krause, M.

1997-01-01

An accepted first-line defense for hydrogen mitigation is to design for the hydrogen to be rapidly mixed with the containment atmosphere and diluted to below flammability concentrations. Then, as hydrogen continues to be produced in the longer term, recombiners can be used to remove hydrogen: recombiners can be located in forced-air ducts or passive recombiners can be distributed within containment and the heat of recombination used to promote local air circulation. However, this principle does not eliminate the possibility of high hydrogen concentrations at locations removed from the recombiners. An improvement on this strategy is to arrange for a specific, buoyancy-driven, overall circulation of the containment atmosphere such that the recombiners can be located within the recirculation flow, immediately downstream of the hydrogen source. This would make the mixing process more predictable and solve the mass-transfer problem associated with distributed recombiners. Ideally, the recombiners would be located just above the hydrogen source so that the heat of recombination would assist the overall circulation. In this way, the hydrogen would be removed as close as possible to the source, thereby minimizing the amount of hydrogen immediately downstream of the source and reducing the hydrogen concentration to acceptable levels at other locations. Such a strategy requires the containment volume to be divided into an upflow path, past the hydrogen source and the recombiner, and a downflow path to complete the circuit. The flow could be generated actively using fans or passively using buoyancy forces arising from the difference in density of gases in the upfiow and downflow paths; the gases in the downflow path being cooled at an elevated heat sink. (author)

Recombination properties of dislocations in GaN

Science.gov (United States)

Yakimov, Eugene B.; Polyakov, Alexander Y.; Lee, In-Hwan; Pearton, Stephen J.

2018-04-01

The recombination activity of threading dislocations in n-GaN with different dislocation densities and different doping levels was studied using electron beam induced current (EBIC). The recombination velocity on a dislocation, also known as the dislocation recombination strength, was calculated. The results suggest that dislocations in n-GaN giving contrast in EBIC are charged and surrounded by a space charge region, as evidenced by the observed dependence of dislocation recombination strength on dopant concentration. For moderate (below ˜108 cm-2) dislocation densities, these defects do not primarily determine the average diffusion length of nonequilibrium charge carriers, although locally, dislocations are efficient recombination sites. In general, it is observed that the effect of the growth method [standard metalorganic chemical vapor deposition (MOCVD), epitaxial lateral overgrowth versions of MOCVD, and hydride vapor phase epitaxy] on the recombination activity of dislocations is not very pronounced, although the average diffusion lengths can widely differ for various samples. The glide of basal plane dislocations at room temperature promoted by low energy electron irradiation does not significantly change the recombination properties of dislocations.

A Pasteurella multocida sialyltransferase displaying dual trans-sialidase activities for production of 3′-sialyl and 6′-sialyl glycans

DEFF Research Database (Denmark)

Guo, Yao; Jers, Carsten; Meyer, Anne S.

2014-01-01

/Kmvalue for the enzyme using 3-sialyllactose as the donor for 6-sialyllactose synthesis at pH 5.4 and 40◦Cwas determined to be 23.22 ± 0.7 M−1s−1. Moreover, the enzyme was capable of catalyzing the synthesisof both 3- and 6-sialylated galactooligosaccharides, when galactooligosaccharides served as acceptors....

Oligonucleotide recombination enabled site-specific mutagenesis in bacteria

Science.gov (United States)

Recombineering refers to a strategy for engineering DNA sequences using a specialized mode of homologous recombination. This technology can be used for rapidly constructing precise changes in bacterial genome sequences in vivo. Oligo recombination is one type of recombineering that uses ssDNA olig...

Recombination: the good, the bad and the variable.

Science.gov (United States)

Stapley, Jessica; Feulner, Philine G D; Johnston, Susan E; Santure, Anna W; Smadja, Carole M

2017-12-19

Recombination, the process by which DNA strands are broken and repaired, producing new combinations of alleles, occurs in nearly all multicellular organisms and has important implications for many evolutionary processes. The effects of recombination can be good , as it can facilitate adaptation, but also bad when it breaks apart beneficial combinations of alleles, and recombination is highly variable between taxa, species, individuals and across the genome. Understanding how and why recombination rate varies is a major challenge in biology. Most theoretical and empirical work has been devoted to understanding the role of recombination in the evolution of sex-comparing between sexual and asexual species or populations. How recombination rate evolves and what impact this has on evolutionary processes within sexually reproducing organisms has received much less attention. This Theme Issue focusses on how and why recombination rate varies in sexual species, and aims to coalesce knowledge of the molecular mechanisms governing recombination with our understanding of the evolutionary processes driving variation in recombination within and between species. By integrating these fields, we can identify important knowledge gaps and areas for future research, and pave the way for a more comprehensive understanding of how and why recombination rate varies. © 2017 The Authors.

Susceptibility of Rocky Mountain bighorn sheep and domestic sheep to pneumonia induced by bighorn and domestic livestock strains of Pasteurella haemolytica.

Science.gov (United States)

Onderka, D K; Rawluk, S A; Wishart, W D

1988-10-01

Bighorn sheep were inoculated intratracheally with suspensions of nonhemolytic Pasteurella haemolytica biotype T (10(12) organisms) unique to wild bighorns, with beta-hemolytic P. haemolytica biotype T (10(12) organisms) isolated from clinically normal domestic sheep or intradermally with half a dose of a cattle vaccine containing P. haemolytica biotype A (10(5) organisms). The bighorn strain caused lobar necrotizing bronchopneumonia whereas both domestic livestock strains precipitated fatal septicemia and fibrinous bronchopneumonia. The serotypes given were T3, T4, T15 and A1 and these were recovered from lung lesions and other organs. In three trials, domestic sheep were inoculated intratracheally with suspensions of bighorn sheep pneumonic lungs, and two concentrations of the P. haemolytica bighorn strain (10(4) and 10(12) organisms). One of these sheep was inoculated intrabronchially. The domestic sheep experienced a transient fever and elevated white blood cell counts. After six days, none of the sheep had lung lesions and inoculated organisms could not be recovered. It is suggested that bighorn sheep are very susceptible to P. haemolytica from domestic livestock and should not be allowed in contact with sheep or cattle.

Genetic recombination of the hepatitis C virus: clinical implications.

Science.gov (United States)

Morel, V; Fournier, C; François, C; Brochot, E; Helle, F; Duverlie, G; Castelain, S

2011-02-01

Genetic recombination is a well-known feature of RNA viruses that plays a significant role in their evolution. Although recombination is well documented for Flaviviridae family viruses, the first natural recombinant strain of hepatitis C virus (HCV) was identified as recently as 2002. Since then, a few other natural inter-genotypic, intra-genotypic and intra-subtype recombinant HCV strains have been described. However, the frequency of recombination may have been underestimated because not all known HCV recombinants are screened for in routine practice. Furthermore, the choice of treatment regimen and its predictive outcome remain problematic as the therapeutic strategy for HCV infection is genotype dependent. HCV recombination also raises many questions concerning its mechanisms and effects on the epidemiological and physiopathological features of the virus. This review provides an update on recombinant HCV strains, the process that gives rise to recombinants and clinical implications of recombination. © 2010 Blackwell Publishing Ltd.

Cell biology of mitotic recombination

DEFF Research Database (Denmark)

Lisby, Michael; Rothstein, Rodney

2015-01-01

Homologous recombination provides high-fidelity DNA repair throughout all domains of life. Live cell fluorescence microscopy offers the opportunity to image individual recombination events in real time providing insight into the in vivo biochemistry of the involved proteins and DNA molecules as w...

Susceptibility of Dall sheep (Ovis dalli dalli) to pneumonia caused by Pasteurella haemolytica.

Science.gov (United States)

Foreyt, W J; Silflow, R M; Lagerquist, J E

1996-10-01

We evaluated susceptibility of Dall sheep (Ovis dalli dalli) to bacterial pneumonia induced by two strains of Pasteurella haemolytica of domestic sheep origin by evaluating the sensitivity of blood neutrophils of eight Dall sheep to lysis by cytotoxins of P. haemolytica, and by intratracheal inoculation of three Dall sheep, two bighorn sheep (Ovis canadensis), and two domestic sheep with 3.7 x 10(6) or 2.5 x 10(7) colony forming units of P. haemolytica. Neutrophils from the Dall sheep were more sensitive to lysis by cytotoxins from supernatants of a P. haemolytica, biotype A, serotype 2 (A2), of domestic sheep origin, than were neutrophils from six bighorn sheep. This cytotoxic bacterium was the same isolate that was used for intratracheal inoculation of two Dall sheep and two domestic sheep. Inoculation of this cytotoxic P. haemolytica A2 resulted in fatal fibrinopurulent pleuropneumonia in the first Dall sheep within 24 hr of inoculation, and pneumonic lesions in the second Dall sheep before it was euthanized 52 hr after inoculation. This strain of P. haemolytica A2 did not cause respiratory disease when inoculated into two domestic sheep. A noncytotoxic strain of P. haemolytica; biotype T, serotype 3,4,10 of domestic sheep origin did not result in pneumonia in the third Dall sheep or two bighorn sheep. Prior to inoculation, P. haemolytica, biotype T isolates were obtained from all three Dall sheep, but none of these isolates was cytotoxic. At necropsy, cytotoxic P. haemolytica A2 was isolated from lungs and other tissues of the two pneumonic Dall sheep. Based on these results, we conclude that Dall sheep appear to be at least as sensitive as bighorn sheep to pneumonia caused by P. haemolytica A2 of domestic sheep origin. Because in vitro and in vivo results appear closely correlated in this and other studies, we believe with additional evaluation and standardization, neutrophil cytotoxicity tests may serve as a substitute for live animal challenges in future

Test tube systems with cutting/recombination operations

Energy Technology Data Exchange (ETDEWEB)

Freund, R. [Technische Universitaet Wien (Austria); Csuhaj-Varju, E. [Computer and Automation Institute, Budapest (Hungary); Wachtler, F. [Universitaet Wien (Austria)

1996-12-31

We introduce test tube systems based on operations that are closely related to the splicing operations, i.e. we consider the operations of cutting a string at a specific site into two pieces with marking them at the cut ends and of recombining two strings with specifically marked endings. Whereas in the splicing of two strings these strings are cut at specific sites and the cut pieces are recombined immediately in a crosswise way, in CR(cutting/recombination)-schemes cutting can happen independently from recombining the cut pieces. Test tube systems based on these operations of cutting and recombination turn out to have maximal generative power even if only very restricted types of input filters for the test tubes are used for the redistribution of the contents of the test tubes after a period of cuttings and recombinations in the test tubes. 10 refs.

Atomic excitation and recombination in external fields

International Nuclear Information System (INIS)

Nayfeh, M.H.; Clark, C.W.

1985-01-01

This volume offers a timely look at Rydberg states of atoms in external fields and dielectronic recombination. Each topic provides authoritative coverage, presents a fresh account of a flourishing field of current atomic physics and introduces new opportunities for discovery and development. Topics considered include electron-atom scattering in external fields; observations of regular and irregular motion as exemplified by the quadratic zeeman effect and other systems; Rydberg atoms in external fields and the Coulomb geometry; crossed-field effects in the absorption spectrum of lithium in a magnetic field; precise studies of static electric field ionization; widths and shapes of stark resonances in sodium above the saddle point; studies of electric field effects and barium autoionizing resonances; autoionization and dielectronic recombination in plasma electric microfields; dielectronic recombination measurements on multicharged ions; merged beam studies of dielectronic recombination; Rydberg atoms and dielectronic recombination in astrophysics; and observations on dielectronic recombination

Genetic evidence for inducibility of recombination competence in yeast

International Nuclear Information System (INIS)

Fabre, F.; Roman, H.

1977-01-01

Recombination between unirradiated chromosomes was induced by UV or x-ray irradiation of haploids followed by a mating with heteroallelic diploids of Saccharomyces cerevisiae. The selected event of intragenic recombination did not involve the participation of the irradiated chromosome and apparently was not caused by lesions introduced into the unirradiated chromosomes by some indirect process. The results favor the idea that recombination is repressed in the majority of vegetative cells and that one effect of radiation is the release of some factor(s) necessary for recombination. Consequently, the proportion of competent cells (i.e., cells able to recombine) in the population increases. This competent state seems necessary not only for the recombinational repair of radiation-induced lesions but also, since recombinants are produced in the absence of such lesions, for spontaneous recombination. Photoreactivation of the UV-irradiated haploids led to a decrease in the production of recombinants. Hence, lesions in the DNA appear to be responsible for the induction of the recombinational ability

Three-body recombination of cold fermionic atoms

International Nuclear Information System (INIS)

Suno, H; Esry, B D; Greene, Chris H

2003-01-01

Recombination of identical, spin-polarized fermions in cold three-body collisions is investigated. We parametrize the mechanisms for recombination in terms of the 'scattering volume' V p and another length scale r 0 . Model two-body interactions were used within the framework of the adiabatic hyperspherical representation. We examine the recombination rate K 3 as a function of the collision energy E for various values of V p . Not only do we consider the dominant J Π = 1 + case, but also the next-leading order contributions from J Π = 1 - and 3 - . We discuss the behaviour near a two-body resonance and the expected universality of fermionic recombination. Comparisons with boson recombination are considered in detail

Recombination Modulates How Selection Affects Linked Sites in Drosophila

Science.gov (United States)

McGaugh, Suzanne E.; Heil, Caiti S. S.; Manzano-Winkler, Brenda; Loewe, Laurence; Goldstein, Steve; Himmel, Tiffany L.; Noor, Mohamed A. F.

2012-01-01

One of the most influential observations in molecular evolution has been a strong association between local recombination rate and nucleotide polymorphisms across the genome. This is interpreted as evidence for ubiquitous natural selection. The alternative explanation, that recombination is mutagenic, has been rejected by the absence of a similar association between local recombination rate and nucleotide divergence between species. However, many recent studies show that recombination rates are often very different even in closely related species, questioning whether an association between recombination rate and divergence between species has been tested satisfactorily. To circumvent this problem, we directly surveyed recombination across approximately 43% of the D. pseudoobscura physical genome in two separate recombination maps and 31% of the D. miranda physical genome, and we identified both global and local differences in recombination rate between these two closely related species. Using only regions with conserved recombination rates between and within species and accounting for multiple covariates, our data support the conclusion that recombination is positively related to diversity because recombination modulates Hill–Robertson effects in the genome and not because recombination is predominately mutagenic. Finally, we find evidence for dips in diversity around nonsynonymous substitutions. We infer that at least some of this reduction in diversity resulted from selective sweeps and examine these dips in the context of recombination rate. PMID:23152720

Recombinational repair: workshop summary

International Nuclear Information System (INIS)

Howard-Flanders, P.

1983-01-01

Recombinational repair may or may not be synonymous with postreplication repair. Considerable progress has been made in the study of the relevant enzymes, particularly those from bacteria. In this workshop we focus on the recombination enzyme RecA protein. What structural changes take place in the protein and in DNA during repair. How does homologous pairing take place. How is ATP hydrolysis coupled to the stand exchange reaction and the formation of heteroduplx DNA. Turning to another enzyme needed for certain kinds of bacterial recombination, we will ask whether the purified recB protein and recC protein complement each other and are sufficient for exonuclease V activity. In higher cells, we would like to know whether sister exchanges, which occur in bacteria after uv irradiation, are also seen in animal cells

Recombinant vaccines: experimental and applied aspects

DEFF Research Database (Denmark)

Lorenzen, Niels

1999-01-01

Development of vaccines for aquaculture fish represent an important applied functional aspect of fish immunology research. Particularly in the case of recombinant vaccines, where a single antigen is usually expected to induce immunity to a specific pathogen, knowledge of mechanisms involved...... in induction of a protective immune response may become vital. The few recombinant vaccines licensd so far, despite much research during the last decade, illustrate that this is not a straightforward matter. However, as vaccine technology as well as our knowledge of the fish immune system is steadily improved......, these fields will open up a number of interesting research objectives of mutual benefit. Recent aspects of recombinant protein vaccines, live recombinant vaccines and DNA vaccines are discussed....

Mitigating Mitochondrial Genome Erosion Without Recombination.

Science.gov (United States)

Radzvilavicius, Arunas L; Kokko, Hanna; Christie, Joshua R

2017-11-01

Mitochondria are ATP-producing organelles of bacterial ancestry that played a key role in the origin and early evolution of complex eukaryotic cells. Most modern eukaryotes transmit mitochondrial genes uniparentally, often without recombination among genetically divergent organelles. While this asymmetric inheritance maintains the efficacy of purifying selection at the level of the cell, the absence of recombination could also make the genome susceptible to Muller's ratchet. How mitochondria escape this irreversible defect accumulation is a fundamental unsolved question. Occasional paternal leakage could in principle promote recombination, but it would also compromise the purifying selection benefits of uniparental inheritance. We assess this tradeoff using a stochastic population-genetic model. In the absence of recombination, uniparental inheritance of freely-segregating genomes mitigates mutational erosion, while paternal leakage exacerbates the ratchet effect. Mitochondrial fusion-fission cycles ensure independent genome segregation, improving purifying selection. Paternal leakage provides opportunity for recombination to slow down the mutation accumulation, but always at a cost of increased steady-state mutation load. Our findings indicate that random segregation of mitochondrial genomes under uniparental inheritance can effectively combat the mutational meltdown, and that homologous recombination under paternal leakage might not be needed. Copyright © 2017 by the Genetics Society of America.

The effect of a single recombination event

DEFF Research Database (Denmark)

Schierup, Mikkel Heide; Jensen, Thomas Mailund; Wiuf, Carsten

We investigate the variance in how visible a single recombination event is in a SNP data set as a function of the type of recombination event and its age. Data is simulated under the coalescent with recombination and inference is by the popular composite likelihood methods. The major determinant...

Recombination rate plasticity: revealing mechanisms by design

Science.gov (United States)

Sefick, Stephen; Rushton, Chase

2017-01-01

For over a century, scientists have known that meiotic recombination rates can vary considerably among individuals, and that environmental conditions can modify recombination rates relative to the background. A variety of external and intrinsic factors such as temperature, age, sex and starvation can elicit ‘plastic’ responses in recombination rate. The influence of recombination rate plasticity on genetic diversity of the next generation has interesting and important implications for how populations evolve. Further, many questions remain regarding the mechanisms and molecular processes that contribute to recombination rate plasticity. Here, we review 100 years of experimental work on recombination rate plasticity conducted in Drosophila melanogaster. We categorize this work into four major classes of experimental designs, which we describe via classic studies in D. melanogaster. Based on these studies, we highlight molecular mechanisms that are supported by experimental results and relate these findings to studies in other systems. We synthesize lessons learned from this model system into experimental guidelines for using recent advances in genotyping technologies, to study recombination rate plasticity in non-model organisms. Specifically, we recommend (1) using fine-scale genome-wide markers, (2) collecting time-course data, (3) including crossover distribution measurements, and (4) using mixed effects models to analyse results. To illustrate this approach, we present an application adhering to these guidelines from empirical work we conducted in Drosophila pseudoobscura. This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’. PMID:29109222

Recombination analysis based on the complete genome of bocavirus

Directory of Open Access Journals (Sweden)

Chen Shengxia

2011-04-01

Full Text Available Abstract Bocavirus include bovine parvovirus, minute virus of canine, porcine bocavirus, gorilla bocavirus, and Human bocaviruses 1-4 (HBoVs. Although recent reports showed that recombination happened in bocavirus, no systematical study investigated the recombination of bocavirus. The present study performed the phylogenetic and recombination analysis of bocavirus over the complete genomes available in GenBank. Results confirmed that recombination existed among bocavirus, including the likely inter-genotype recombination between HBoV1 and HBoV4, and intra-genotype recombination among HBoV2 variants. Moreover, it is the first report revealing the recombination that occurred between minute viruses of canine.

FASEB Summer Research Conference. Genetic Recombination and Chromosome Rearrangements

Energy Technology Data Exchange (ETDEWEB)

Jinks-Robertson, Sue

2002-02-01

The 2001 meeting entitled ''Genetic Recombination and Genome Rearrangements'' was held July 21-26 in Snowmass, Colorado. The goal of the meeting was to bring together scientists using diverse approaches to study all aspects of genetic recombination. This goal was achieved by integrating talks covering the genetics, biochemistry and structural biology of homologous recombination, site-specific recombination, and nonhomologous recombination. The format of the meeting consisted of a keynote address on the opening evening, two formal plenary sessions on each of the four full meeting days, a single afternoon workshop consisting of short talks chosen from among submitted abstracts, and afternoon poster sessions on each of the four full meeting days. The eight plenary session were entitled: (1) Recombination Mechanisms, (2) Prokaryotic Recombination, (3) Repair and Recombination, (4) Site-specific Recombination and Transposition, (5) Eukaryotic Recombination I, (6) Genome Rearrangements, (7) Meiosis, and (8) Eukaryotic Recombination II. Each session included a mix of genetic, biochemical and structural talks; talks were limited to 20 minutes, followed by 10 minutes of very lively, general discussion. Much of the data presented in the plenary sessions was unpublished, thus providing attendees with the most up-to-date knowledge of this rapidly-moving field.

Hadron Correlations and Parton Recombination

Energy Technology Data Exchange (ETDEWEB)

Fries, R.J. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)]. E-mail: rjfries@comp.tamu.edu

2007-02-15

Parton recombination has been found to be an extremely useful model to understand hadron production at the Relativistic Heavy Ion Collider. It is particularly important to explore its connections with hard processes. This article reviews some of the aspects of the quark recombination model and places particular emphasis on hadron correlations.

Exceptionally high levels of recombination across the honey bee genome.

Science.gov (United States)

Beye, Martin; Gattermeier, Irene; Hasselmann, Martin; Gempe, Tanja; Schioett, Morten; Baines, John F; Schlipalius, David; Mougel, Florence; Emore, Christine; Rueppell, Olav; Sirviö, Anu; Guzmán-Novoa, Ernesto; Hunt, Greg; Solignac, Michel; Page, Robert E

2006-11-01

The first draft of the honey bee genome sequence and improved genetic maps are utilized to analyze a genome displaying 10 times higher levels of recombination (19 cM/Mb) than previously analyzed genomes of higher eukaryotes. The exceptionally high recombination rate is distributed genome-wide, but varies by two orders of magnitude. Analysis of chromosome, sequence, and gene parameters with respect to recombination showed that local recombination rate is associated with distance to the telomere, GC content, and the number of simple repeats as described for low-recombining genomes. Recombination rate does not decrease with chromosome size. On average 5.7 recombination events per chromosome pair per meiosis are found in the honey bee genome. This contrasts with a wide range of taxa that have a uniform recombination frequency of about 1.6 per chromosome pair. The excess of recombination activity does not support a mechanistic role of recombination in stabilizing pairs of homologous chromosome during chromosome pairing. Recombination rate is associated with gene size, suggesting that introns are larger in regions of low recombination and may improve the efficacy of selection in these regions. Very few transposons and no retrotransposons are present in the high-recombining genome. We propose evolutionary explanations for the exceptionally high genome-wide recombination rate.

Three-particle recombination at low temperature: QED approach

International Nuclear Information System (INIS)

Bhattacharyya, S.; Roy, A.

2001-01-01

A theoretical study of three-body recombination of proton in presence of a spectator electron with electronic beam at near-zero temperature is presented using field theory and invariant Lorentz gauge. Contributions from the Feynman diagrams of different orders give an insight into the physics of the phenomena. Recombination rate coefficient is obtained for low lying principal quantum number n = 1 to 10. At a fixed ion beam temperature (300 K) recombination rate coefficient is found to increase in general with n, having a flat and a sharp peak at quantum states 3 to 5, respectively. In absence of any theoretical and experimental results for low temperature formation of H-atom by three-body recombination at low lying quantum states, we have presented the theoretical results of Stevefelt and group for three-body recombination of deuteron with electron along with the present results. Three-body recombination of antihydrogen in antiproton-positron plasma is expected to yield similar result as that for three-body recombination of hydrogen formation in proton-electron plasma. The necessity for experimental investigation of low temperature three-body recombination at low quantum states is stressed. (author)

The importance of subcutaneous abscess infection by Pasteurella spp. and Staphylococcus aureus as a cause of meat condemnation in slaughtered commercial rabbits

Directory of Open Access Journals (Sweden)

A. Ferreira

2014-12-01

Full Text Available Subcutaneous abscesses are lesions frequently reported in commercial rabbits. Both at farm and slaughterhouse level, these lesions are responsible for economic losses and a potential decrease in meat quality. The present study was devised to identify the main causes of meat condemnation in slaughtered commercial rabbits and assess the importance of abscess lesions in this domain. For these purposes, 281423 rabbits were evaluated during meat inspection at the slaughterhouse. The results achieved showed that subcutaneous abscesses were the major cause of condemnation, being responsible for the rejection of 1355 (0.48% rabbit carcasses. The main affected area was the hind limbs (31.37%, followed by the cervical area (23.10%. Microbiological analyses of 27 abscess samples indicated Pasteurella spp. as the bacteria mostly isolated (59.3%, followed by Staphylococcus aureus (25.9%. These results enable us to advise the industry on the significance of abscesses as an important cause of economic losses, due to meat condemnation during post mortem inspection, and highlight the importance of implementing monitoring plans as a way to control this pathological problem.

Activated recombinant adenovirus proteinases

Science.gov (United States)

Anderson, Carl W.; Mangel, Walter F.

1999-08-10

This application describes methods and expression constructs for producing activatable recombinant adenovirus proteinases. Purified activatable recombinant adenovirus proteinases and methods of purification are described. Activated adenovirus proteinases and methods for obtaining activated adenovirus proteinases are further included. Isolated peptide cofactors of adenovirus proteinase activity, methods of purifying and identifying said peptide cofactors are also described. Antibodies immunoreactive with adenovirus proteinases, immunospecific antibodies, and methods for preparing them are also described. Other related methods and materials are also described.

Hadron correlations from recombination

Energy Technology Data Exchange (ETDEWEB)

Fries, Rainer J [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2005-01-01

Quark recombination is a successful model to describe the hadronization of a deconfined quark gluon plasma. Jet-like dihadron correlations measured at RHIC provide a challenge for this picture. We discuss how correlations between hadrons can arise from correlations between partons before hadronization. An enhancement of correlations through the recombination process, similar to the enhancement of elliptic flow is found. Hot spots from completely or partially quenched jets are a likely source of such parton correlations.

X-ray- and TEM-induced mitotic recombination in Drosophila melanogaster: Unequal and sister-strand recombination

International Nuclear Information System (INIS)

Becker, H.J.

1975-01-01

Twin mosaic spots of dark-apricot and light-apricot ommatidia were found in the eyes of wsup(a)/wsup(a) females, of wsup(a) males, of females homozygous for In(1)sc 4 , wsup(a) and of attached-X females homozygous for wsup(a). The flies were raised from larvae which had been treated with 1,630 R of X-rays at the age of 48-52 hours. An additional group of wsup(a)/wsup(a) females and wsup(a) males came from larvae that had been fed with triethylene melamine (TEM) at the age of 22-24 hours. The twin spots apparently were the result of induced unequal mitotic recombination, i.e. from unequal sister-strand recombination in the males and from unequal sister-strand recombination as well as, possibly, unequal recombination between homologous strands in the females. That is, a duplication resulted in wsup(a)Dpwsup(a)/wsup(a) dark-apricto ommatidia and the corresponding deficiency in an adjacent area of wsup(a)/Dfwsup(a) light-apricot ommatidia. In an additional experiment sister-strand mitotic recombination in the ring-X chromosome of ring-X/rod-X females heterozygous for w and wsup(co) is believed to be the cause for X-ray induced single mosaic spots that show the phenotype of the rod-X marker. (orig.) [de

Two novel porcine epidemic diarrhea virus (PEDV) recombinants from a natural recombinant and distinct subtypes of PEDV variants.

Science.gov (United States)

Chen, Nanhua; Li, Shuangjie; Zhou, Rongyun; Zhu, Meiqin; He, Shan; Ye, Mengxue; Huang, Yucheng; Li, Shuai; Zhu, Cong; Xia, Pengpeng; Zhu, Jianzhong

2017-10-15

Porcine epidemic diarrhea virus (PEDV) causes devastating impact on global pig-breeding industry and current vaccines have become not effective against the circulating PEDV variants since 2011. During the up-to-date investigation of PEDV prevalence in Fujian China 2016, PEDV was identified in vaccinated pig farms suffering severe diarrhea while other common diarrhea-associated pathogens were not detected. Complete genomes of two PEDV representatives (XM1-2 and XM2-4) were determined. Genomic comparison showed that these two viruses share the highest nucleotide identities (99.10% and 98.79%) with the 2011 ZMDZY strain, but only 96.65% and 96.50% nucleotide identities with the attenuated CV777 strain. Amino acid alignment of spike (S) proteins indicated that they have the similar mutation, insertion and deletion pattern as other Chinese PEDV variants but also contain several unique substitutions. Phylogenetic analysis showed that 2016 PEDV variants belong to the cluster of recombination strains but form a new branch. Recombination detection suggested that both XM1-2 and XM2-4 are inter-subgroup recombinants with breakpoints within ORF1b. Remarkably, the natural recombinant HNQX-3 isolate serves as a parental virus for both natural recombinants identified in this study. This up-to-date investigation provides the direct evidence that natural recombinants may serve as parental viruses to generate recombined PEDV progenies that are probably associated with the vaccination failure. Copyright © 2017. Published by Elsevier B.V.

Rapid generation of markerless recombinant MVA vaccines by en passant recombineering of a self-excising bacterial artificial chromosome.

Science.gov (United States)

Cottingham, Matthew G; Gilbert, Sarah C

2010-09-01

The non-replicating poxviral vector modified vaccinia virus Ankara (MVA) is currently a leading candidate for development of novel recombinant vaccines against globally important diseases. The 1980s technology for making recombinant MVA (and other poxviruses) is powerful and robust, but relies on rare recombination events in poxviral-infected cells. In the 21st century, it has become possible to apply bacterial artificial chromosome (BAC) technology to poxviruses, as first demonstrated by B. Moss' lab in 2002 for vaccinia virus. A similar BAC clone of MVA was subsequently derived, but while recombination-mediated genetic engineering for rapid production was used of deletion mutants, an alternative method was required for efficient insertion of transgenes. Furthermore "markerless" viruses, which carry no trace of the selectable marker used for their isolation, are increasingly required for clinical trials, and the viruses derived via the new method contained the BAC sequence in their genomic DNA. Two methods are adapted to MVA-BAC to provide more rapid generation of markerless recombinants in weeks rather than months. "En passant" recombineering is applied to the insertion of a transgene expression cassette and the removal of the selectable marker in bacteria; and a self-excising variant of MVA-BAC is constructed, in which the BAC cassette region is rapidly and efficiently lost from the viral genome following rescue of the BAC into infectious virus. These methods greatly facilitate and accelerate production of recombinant MVA, including markerless constructs. Copyright 2010 Elsevier B.V. All rights reserved.

ORF Alignment: NC_002663 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available multocida ... subsp. multocida str. Pm70] ... Length = 108 ... Query: 2 ... IEVNQQQIETDAHGYLLDLTQWDEDVARAIAQQENIDLTDAH...WEVIYFVRAFYQEYKTSP 61 ... IEVNQQQIETDAHGYLLDLTQWDEDVARAIAQQENIDLTDAH...WEVIYFVRAFYQEYKTSP Sbjct: 1 ... IEVNQQQIETDAHGYLLDLTQWDEDVARAIAQQENIDLTDAHWEVIYFVRAFYQEYKTSP 60 ...

ORF Alignment: NC_002663 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available multocida ... subsp. multocida str. Pm70] ... Length = 159 ... Query: 2 ... TTNRQEVLQNRLGPEIQELKAQ...CKTVMLATVGEDGNPNVSYAPFAINNGEYQVFISTIAR 61 ... TTNRQEVLQNRLGPEIQELKAQCKTVML...ATVGEDGNPNVSYAPFAINNGEYQVFISTIAR Sbjct: 1 ... TTNRQEVLQNRLGPEIQELKAQCKTVMLATVGEDGNPNVSYAPFAINNGEYQVFISTIAR 60

Mechanisms and factors that influence high frequency retroviral recombination

DEFF Research Database (Denmark)

Delviks-Frankenberry, Krista; Galli, Andrea; Nikolaitchik, Olga

2011-01-01

With constantly changing environmental selection pressures, retroviruses rely upon recombination to reassort polymorphisms in their genomes and increase genetic diversity, which improves the chances for the survival of their population. Recombination occurs during DNA synthesis, whereby reverse...... transcriptase undergoes template switching events between the two copackaged RNAs, resulting in a viral recombinant with portions of the genetic information from each parental RNA. This review summarizes our current understanding of the factors and mechanisms influencing retroviral recombination, fidelity...... of the recombination process, and evaluates the subsequent viral diversity and fitness of the progeny recombinant. Specifically, the high mutation rates and high recombination frequencies of HIV-1 will be analyzed for their roles in influencing HIV-1 global diversity, as well as HIV-1 diagnosis, drug treatment...

Induction of homologous recombination in Saccharomyces cerevisiae.

Science.gov (United States)

Simon, J R; Moore, P D

1988-09-01

We have investigated the effects of UV irradiation of Saccharomyces cerevisiae in order to distinguish whether UV-induced recombination results from the induction of enzymes required for homologous recombination, or the production of substrate sites for recombination containing regions of DNA damage. We utilized split-dose experiments to investigate the induction of proteins required for survival, gene conversion, and mutation in a diploid strain of S. cerevisiae. We demonstrate that inducing doses of UV irradiation followed by a 6 h period of incubation render the cells resistant to challenge doses of UV irradiation. The effects of inducing and challenge doses of UV irradiation upon interchromosomal gene conversion and mutation are strictly additive. Using the yeast URA3 gene cloned in non-replicating single- and double-stranded plasmid vectors that integrate into chromosomal genes upon transformation, we show that UV irradiation of haploid yeast cells and homologous plasmid DNA sequences each stimulate homologous recombination approximately two-fold, and that these effects are additive. Non-specific DNA damage has little effect on the stimulation of homologous recombination, as shown by studies in which UV-irradiated heterologous DNA was included in transformation/recombination experiments. We further demonstrate that the effect of competing single- and double-stranded heterologous DNA sequences differs in UV-irradiated and unirradiated cells, suggesting an induction of recombinational machinery in UV-irradiated S. cerevisiae cells.

Spectrum Recombination.

Science.gov (United States)

Greenslade, Thomas B., Jr.

1984-01-01

Describes several methods of executing lecture demonstrations involving the recombination of the spectrum. Groups the techniques into two general classes: bringing selected portions of the spectrum together using lenses or mirrors and blurring the colors by rapid movement or foreshortening. (JM)

Genetic analysis of variation in human meiotic recombination.

Directory of Open Access Journals (Sweden)

Reshmi Chowdhury

2009-09-01

Full Text Available The number of recombination events per meiosis varies extensively among individuals. This recombination phenotype differs between female and male, and also among individuals of each gender. In this study, we used high-density SNP genotypes of over 2,300 individuals and their offspring in two datasets to characterize recombination landscape and to map the genetic variants that contribute to variation in recombination phenotypes. We found six genetic loci that are associated with recombination phenotypes. Two of these (RNF212 and an inversion on chromosome 17q21.31 were previously reported in the Icelandic population, and this is the first replication in any other population. Of the four newly identified loci (KIAA1462, PDZK1, UGCG, NUB1, results from expression studies provide support for their roles in meiosis. Each of the variants that we identified explains only a small fraction of the individual variation in recombination. Notably, we found different sequence variants associated with female and male recombination phenotypes, suggesting that they are regulated by different genes. Characterization of genetic variants that influence natural variation in meiotic recombination will lead to a better understanding of normal meiotic events as well as of non-disjunction, the primary cause of pregnancy loss.

Recombination in Avian Gamma-Coronavirus Infectious Bronchitis Virus

Directory of Open Access Journals (Sweden)

Mark W. Jackwood

2011-09-01

Full Text Available Recombination in the family Coronaviridae has been well documented and is thought to be a contributing factor in the emergence and evolution of different coronaviral genotypes as well as different species of coronavirus. However, there are limited data available on the frequency and extent of recombination in coronaviruses in nature and particularly for the avian gamma-coronaviruses where only recently the emergence of a turkey coronavirus has been attributed solely to recombination. In this study, the full-length genomes of eight avian gamma-coronavirus infectious bronchitis virus (IBV isolates were sequenced and along with other full-length IBV genomes available from GenBank were analyzed for recombination. Evidence of recombination was found in every sequence analyzed and was distributed throughout the entire genome. Areas that have the highest occurrence of recombination are located in regions of the genome that code for nonstructural proteins 2, 3 and 16, and the structural spike glycoprotein. The extent of the recombination observed, suggests that this may be one of the principal mechanisms for generating genetic and antigenic diversity within IBV. These data indicate that reticulate evolutionary change due to recombination in IBV, likely plays a major role in the origin and adaptation of the virus leading to new genetic types and strains of the virus.

The unconventional xer recombination machinery of Streptococci/Lactococci

NARCIS (Netherlands)

Le Bourgeois, Pascal; Bugarel, Marie; Campo, Nathalie; Daveran-Mingot, Marie-Line; Labonte, Jessica; Lanfranchi, Daniel; Lautier, Thomas; Pages, Carine; Ritzenthaler, Paul

Homologous recombination between circular sister chromosomes during DNA replication in bacteria can generate chromosome dimers that must be resolved into monomers prior to cell division. In Escherichia coli, dimer resolution is achieved by site-specific recombination, Xer recombination, involving

ORF Alignment: NC_002663 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available eurella multocida subsp. multocida str. Pm70] ... Length = 97 ... Query: 3 ... YYVIFAQDNPNTLAQRLAVREKHLARLTQLQAEDRLLVAGPNPAIDS...ENPGEAGFTGSTV 62 ... YYVIFAQDNPNTLAQRLAVREKHLARLTQLQAEDRLLVAGPNPAIDS...ENPGEAGFTGSTV Sbjct: 1 ... YYVIFAQDNPNTLAQRLAVREKHLARLTQLQAEDRLLVAGPNPAIDSENPGEAGFTGSTV 60 ...

Graded Recombination Layers for Multijunction Photovoltaics

KAUST Repository

Koleilat, Ghada I.; Wang, Xihua; Sargent, Edward H.

2012-01-01

it to achieve multicolor and spectrally tunable behavior. In series-connected current-matched multijunction devices, the recombination layers must allow the hole current from one cell to recombine, with high efficiency and low voltage loss, with the electron

V(D)J recombination frequency is affected by the sequence interposed between a pair of recombination signals: sequence comparison reveals a putative recombinational enhancer element

DEFF Research Database (Denmark)

Roch, F A; Hobi, R; Berchtold, M W

1997-01-01

respectively, can markedly affect the frequency of V(D)J recombination. We report that the entire Emu, the Emu core as well as its flanking 5' and 3' matrix associated regions (5' and 3' MARs) upregulate V(D)J recombination while the downstream section of the 3' MAR of Emu does not. Also, prokaryotic sequences...

Bio-equivalent doses of recombinent HCG and recombinent LH during ovarian stimulation result in similar oestradiol output

DEFF Research Database (Denmark)

Alsbjerg, Birgit; Elbaek, Helle Olesen; Laursen, Rita Jakubcionyte

2017-01-01

In nature, HCG is secreted by the implanting embryo from peri-implantation and onwards. In contrast, LH is mandatory for steroidogenesis and follicular development during the follicular phase, working in synergy with FSH. Moreover, LH is mandatory for the function of the corpus luteum. Although LH...... and HCG bind to the same receptor, significant molecular, structural and functional differences exist, inducing differences in bioactivity. This randomized controlled study compared the effect of recombinant FSH stimulation combined with daily either micro-dose recombinant HCG or recombinant LH...

Mechanisms and Factors that Influence High Frequency Retroviral Recombination

Science.gov (United States)

Delviks-Frankenberry, Krista; Galli, Andrea; Nikolaitchik, Olga; Mens, Helene; Pathak, Vinay K.; Hu, Wei-Shau

2011-01-01

With constantly changing environmental selection pressures, retroviruses rely upon recombination to reassort polymorphisms in their genomes and increase genetic diversity, which improves the chances for the survival of their population. Recombination occurs during DNA synthesis, whereby reverse transcriptase undergoes template switching events between the two copackaged RNAs, resulting in a viral recombinant with portions of the genetic information from each parental RNA. This review summarizes our current understanding of the factors and mechanisms influencing retroviral recombination, fidelity of the recombination process, and evaluates the subsequent viral diversity and fitness of the progeny recombinant. Specifically, the high mutation rates and high recombination frequencies of HIV-1 will be analyzed for their roles in influencing HIV-1 global diversity, as well as HIV-1 diagnosis, drug treatment, and vaccine development. PMID:21994801

Recombinant innovation and endogenous technological transitions

NARCIS (Netherlands)

Frenken, K.; Izquierdo, L.R.; Zeppini, P.

2012-01-01

We propose a model of technological transitions based on two different types of innovations. Branching innovations refer to technological improvements along a particular path, while recombinant innovations represent fusions of multiple paths. Recombinant innovations create "short-cuts" which reduce

Bimolecular recombination in ambipolar organic field effect transistors

NARCIS (Netherlands)

Charrier, D. S. H.; de Vries, T.; Mathijssen, S. G. J.; Geluk, E. -J.; Smits, E. C. P.; Kemerink, M.; Janssen, R. A. J.

In ambipolar organic field effect transistors (OFET) the shape of the channel potential is intimately related to the recombination zone width W, and hence to the electron-hole recombination strength. Experimentally, the recombination profile can be assessed by scanning Kelvin probe microscopy

Bimolecular recombination in ambipolar organic field effect transistors

NARCIS (Netherlands)

Charrier, D.S.H.; Vries, T. de; Mathijssen, S.G.J.; Geluk, E.-J.; Smits, E.C.P.; Kemerink, M.; Janssen, R.A.J.

2009-01-01

In ambipolar organic field effect transistors (OFET) the shape of the channel potential is intimately related to the recombination zone width W, and hence to the electron–hole recombination strength. Experimentally, the recombination profile can be assessed by scanning Kelvin probe microscopy

Genome-wide variation in recombination rate in Eucalyptus.

Science.gov (United States)

Gion, Jean-Marc; Hudson, Corey J; Lesur, Isabelle; Vaillancourt, René E; Potts, Brad M; Freeman, Jules S

2016-08-09

Meiotic recombination is a fundamental evolutionary process. It not only generates diversity, but influences the efficacy of natural selection and genome evolution. There can be significant heterogeneity in recombination rates within and between species, however this variation is not well understood outside of a few model taxa, particularly in forest trees. Eucalypts are forest trees of global economic importance, and dominate many Australian ecosystems. We studied recombination rate in Eucalyptus globulus using genetic linkage maps constructed in 10 unrelated individuals, and markers anchored to the Eucalyptus reference genome. This experimental design provided the replication to study whether recombination rate varied between individuals and chromosomes, and allowed us to study the genomic attributes and population genetic parameters correlated with this variation. Recombination rate varied significantly between individuals (range = 2.71 to 3.51 centimorgans/megabase [cM/Mb]), but was not significantly influenced by sex or cross type (F1 vs. F2). Significant differences in recombination rate between chromosomes were also evident (range = 1.98 to 3.81 cM/Mb), beyond those which were due to variation in chromosome size. Variation in chromosomal recombination rate was significantly correlated with gene density (r = 0.94), GC content (r = 0.90), and the number of tandem duplicated genes (r = -0.72) per chromosome. Notably, chromosome level recombination rate was also negatively correlated with the average genetic diversity across six species from an independent set of samples (r = -0.75). The correlations with genomic attributes are consistent with findings in other taxa, however, the direction of the correlation between diversity and recombination rate is opposite to that commonly observed. We argue this is likely to reflect the interaction of selection and specific genome architecture of Eucalyptus. Interestingly, the differences amongst

Induction of intrachromosomal homologous recombination in whole plants

International Nuclear Information System (INIS)

Puchta, H.; Swoboda, P.; Hohn, B.

1995-01-01

The influence of different factors on frequencies of intrachromosomal homologous recombination in whole Arabidopsis thaliana and tobacco plants was analyzed using a disrupted β-glucuronidase marker gene. Recombination frequencies were enhanced several fold by DNA damaging agents like UV-light or MMS (methyl methanesulfonate). Applying 3-methoxybenzamide (3-MB), an inhibitor of poly(ADP)ribose polymerase (PARP), an enzyme that is postulated to be involved in DNA repair, enhanced homologous recombination frequencies strongly. These findings indicate that homologous recombination is involved in DNA repair and can (at least partially) compensate for other DNA repair pathways. Indications that recombination in plants can be induced by environmental stress factors that are not likely to be involved in DNA metabolism were also found; Arabidopsis plants growing in a medium containing 0.1 M NaCl exhibited elevated recombination frequencies. The possible general effects of ‘environmental’ challenges on genome flexibility are discussed. (author)

Metal binding proteins, recombinant host cells and methods

Science.gov (United States)

Summers, Anne O.; Caguiat, Jonathan J.

2004-06-15

The present disclosure provides artificial heavy metal binding proteins termed chelons by the inventors. These chelons bind cadmium and/or mercuric ions with relatively high affinity. Also disclosed are coding sequences, recombinant DNA molecules and recombinant host cells comprising those recombinant DNA molecules for expression of the chelon proteins. In the recombinant host cells or transgenic plants, the chelons can be used to bind heavy metals taken up from contaminated soil, groundwater or irrigation water and to concentrate and sequester those ions. Recombinant enteric bacteria can be used within the gastrointestinal tracts of animals or humans exposed to toxic metal ions such as mercury and/or cadmium, where the chelon recombinantly expressed in chosen in accordance with the ion to be rededicated. Alternatively, the chelons can be immobilized to solid supports to bind and concentrate heavy metals from a contaminated aqueous medium including biological fluids.

Electric hydrogen recombiner special tests

International Nuclear Information System (INIS)

Wilson, J.F.

1975-12-01

Westinghouse has produced an electric hydrogen recombiner to control hydrogen levels in reactor containments following a postulated loss-of-coolant accident. The recombiner underwent extensive testing for NRC qualification (see WCAP 7709-L and Supplements 1, 2, 3, 4). As a result, WCAP 7709-L and Supplements 1, 2, 3, and 4 have been accepted by the NRC for reference in applications not committed to IEEE-323-1974. Supplement 5 and the next supplement will demonstrate conformance to IEEE-323-1974. This supplement describes additional tests, beyond those necessary to qualify the system, which will be referenced in supplement 6. Each test has demonstrated a considerable margin of safety over required performance. Concurrently, the test results increased the fund of technical information on the electric hydrogen recombiner

Frequent intra-subtype recombination among HIV-1 circulating in Tanzania.

Directory of Open Access Journals (Sweden)

Ireen E Kiwelu

Full Text Available The study estimated the prevalence of HIV-1 intra-subtype recombinant variants among female bar and hotel workers in Tanzania. While intra-subtype recombination occurs in HIV-1, it is generally underestimated. HIV-1 env gp120 V1-C5 quasispecies from 45 subjects were generated by single-genome amplification and sequencing (median (IQR of 38 (28-50 sequences per subject. Recombination analysis was performed using seven methods implemented within the recombination detection program version 3, RDP3. HIV-1 sequences were considered recombinant if recombination signals were detected by at least three methods with p-values of ≤0.05 after Bonferroni correction for multiple comparisons. HIV-1 in 38 (84% subjects showed evidence for intra-subtype recombination including 22 with HIV-1 subtype A1, 13 with HIV-1 subtype C, and 3 with HIV-1 subtype D. The distribution of intra-patient recombination breakpoints suggested ongoing recombination and showed selective enrichment of recombinant variants in 23 (60% subjects. The number of subjects with evidence of intra-subtype recombination increased from 29 (69% to 36 (82% over one year of follow-up, although the increase did not reach statistical significance. Adjustment for intra-subtype recombination is important for the analysis of multiplicity of HIV infection. This is the first report of high prevalence of intra-subtype recombination in the HIV/AIDS epidemic in Tanzania, a region where multiple HIV-1 subtypes co-circulate. HIV-1 intra-subtype recombination increases viral diversity and presents additional challenges for HIV-1 vaccine design.

Construction and characterization of a recombinant invertebrate iridovirus.

Science.gov (United States)

Ozgen, Arzu; Muratoglu, Hacer; Demirbag, Zihni; Vlak, Just M; van Oers, Monique M; Nalcacioglu, Remziye

2014-08-30

Chilo iridescent virus (CIV), officially named Insect iridescent virus 6 (IIV6), is the type species of the genus Iridovirus (family Iridoviridae). In this paper we constructed a recombinant CIV, encoding the green fluorescent protein (GFP). This recombinant can be used to investigate viral replication dynamics. We showed that homologous recombination is a valid method to make CIV gene knockouts and to insert foreign genes. The CIV 157L gene, putatively encoding a non-functional inhibitor of apoptosis (IAP), was chosen as target for foreign gene insertion. The gfp open reading frame preceded by the viral mcp promoter was inserted into the 157L locus by homologous recombination in Anthonomus grandis BRL-AG-3A cells. Recombinant virus (rCIV-Δ157L-gfp) was purified by successive rounds of plaque purification. All plaques produced by the purified recombinant virus emitted green fluorescence due to the presence of GFP. One-step growth curves for recombinant and wild-type CIV were similar and the recombinant was fully infectious in vivo. Hence, CIV157L can be inactivated without altering the replication kinetics of the virus. Consequently, the CIV 157L locus can be used as a site for insertion of foreign DNA, e.g. to modify viral properties for insect biocontrol. Copyright © 2014 Elsevier B.V. All rights reserved.

Poliovirus Polymerase Leu420 Facilitates RNA Recombination and Ribavirin Resistance

Science.gov (United States)

Kempf, Brian J.; Peersen, Olve B.

2016-01-01

ABSTRACT RNA recombination is important in the formation of picornavirus species groups and the ongoing evolution of viruses within species groups. In this study, we examined the structure and function of poliovirus polymerase, 3Dpol, as it relates to RNA recombination. Recombination occurs when nascent RNA products exchange one viral RNA template for another during RNA replication. Because recombination is a natural aspect of picornavirus replication, we hypothesized that some features of 3Dpol may exist, in part, to facilitate RNA recombination. Furthermore, we reasoned that alanine substitution mutations that disrupt 3Dpol-RNA interactions within the polymerase elongation complex might increase and/or decrease the magnitudes of recombination. We found that an L420A mutation in 3Dpol decreased the frequency of RNA recombination, whereas alanine substitutions at other sites in 3Dpol increased the frequency of recombination. The 3Dpol Leu420 side chain interacts with a ribose in the nascent RNA product 3 nucleotides from the active site of the polymerase. Notably, the L420A mutation that reduced recombination also rendered the virus more susceptible to inhibition by ribavirin, coincident with the accumulation of ribavirin-induced G→A and C→U mutations in viral RNA. We conclude that 3Dpol Leu420 is critically important for RNA recombination and that RNA recombination contributes to ribavirin resistance. IMPORTANCE Recombination contributes to the formation of picornavirus species groups and the emergence of circulating vaccine-derived polioviruses (cVDPVs). The recombinant viruses that arise in nature are occasionally more fit than either parental strain, especially when the two partners in recombination are closely related, i.e., members of characteristic species groups, such as enterovirus species groups A to H or rhinovirus species groups A to C. Our study shows that RNA recombination requires conserved features of the viral polymerase. Furthermore, a

Genome-wide recombination dynamics are associated with phenotypic variation in maize.

Science.gov (United States)

Pan, Qingchun; Li, Lin; Yang, Xiaohong; Tong, Hao; Xu, Shutu; Li, Zhigang; Li, Weiya; Muehlbauer, Gary J; Li, Jiansheng; Yan, Jianbing

2016-05-01

Meiotic recombination is a major driver of genetic diversity, species evolution, and agricultural improvement. Thus, an understanding of the genetic recombination landscape across the maize (Zea mays) genome will provide insight and tools for further study of maize evolution and improvement. Here, we used c. 50 000 single nucleotide polymorphisms to precisely map recombination events in 12 artificial maize segregating populations. We observed substantial variation in the recombination frequency and distribution along the ten maize chromosomes among the 12 populations and identified 143 recombination hot regions. Recombination breakpoints were partitioned into intragenic and intergenic events. Interestingly, an increase in the number of genes containing recombination events was accompanied by a decrease in the number of recombination events per gene. This kept the overall number of intragenic recombination events nearly invariable in a given population, suggesting that the recombination variation observed among populations was largely attributed to intergenic recombination. However, significant associations between intragenic recombination events and variation in gene expression and agronomic traits were observed, suggesting potential roles for intragenic recombination in plant phenotypic diversity. Our results provide a comprehensive view of the maize recombination landscape, and show an association between recombination, gene expression and phenotypic variation, which may enhance crop genetic improvement. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

RNAi and heterochromatin repress centromeric meiotic recombination

DEFF Research Database (Denmark)

Ellermeier, Chad; Higuchi, Emily C; Phadnis, Naina

2010-01-01

During meiosis, the formation of viable haploid gametes from diploid precursors requires that each homologous chromosome pair be properly segregated to produce an exact haploid set of chromosomes. Genetic recombination, which provides a physical connection between homologous chromosomes, is essen......During meiosis, the formation of viable haploid gametes from diploid precursors requires that each homologous chromosome pair be properly segregated to produce an exact haploid set of chromosomes. Genetic recombination, which provides a physical connection between homologous chromosomes....... Surprisingly, one mutant derepressed for recombination in the heterochromatic mating-type region during meiosis and several mutants derepressed for centromeric gene expression during mitotic growth are not derepressed for centromeric recombination during meiosis. These results reveal a complex relation between...... types of repression by heterochromatin. Our results also reveal a previously undemonstrated role for RNAi and heterochromatin in the repression of meiotic centromeric recombination and, potentially, in the prevention of birth defects by maintenance of proper chromosome segregation during meiosis....

Effects of UV radiation on genetic recombination

International Nuclear Information System (INIS)

Vlahovic, K.; Zahradka, D.; Petranovic, M.; Petranovic, D.

1996-01-01

We have used the model consisting of Escherichia coli cells and l phage to study the effects of UV radiation on genetic recombination. We found two radiation induced processes that reduce or inhibit genetic recombination. One such process leads to the inability of prophage to excise itself from the irradiated bacterial chromosome by the site-specific recombination. The other process was shown to inhibit a type of general recombination by which the prophage transfers one of its genetic markers to the infecting homologous phage. Loss of the prophage ability to take part in both site-specific and general recombination was shown to develop in recB + but not in recB cells. From this we infer that the loss of prophage recombinogenicity in irradiated cells is a consequence of one process in which RecBCD enzyme (the product of recB, recC and recD genes) plays an essential role. (author)

Temporally-controlled site-specific recombination in zebrafish.

Directory of Open Access Journals (Sweden)

Stefan Hans

Full Text Available Conventional use of the site-specific recombinase Cre is a powerful technology in mouse, but almost absent in other vertebrate model organisms. In zebrafish, Cre-mediated recombination efficiency was previously very low. Here we show that using transposon-mediated transgenesis, Cre is in fact highly efficient in this organism. Furthermore, temporal control of recombination can be achieved by using the ligand-inducible CreER(T2. Site-specific recombination only occurs upon administration of the drug tamoxifen (TAM or its active metabolite, 4-hydroxy-tamoxifen (4-OHT. Cre-mediated recombination is detectable already 4 or 2 hours after administration of TAM or 4-OHT, demonstrating fast recombination kinetics. In addition, low doses of TAM allow mosaic labeling of single cells. Combined, our results show that conditional Cre/lox will be a valuable tool for both, embryonic and adult zebrafish studies. Furthermore, single copy insertion transgenesis of Cre/lox constructs suggest a strategy suitable also for other organisms.

Algae-based oral recombinant vaccines

Science.gov (United States)

Specht, Elizabeth A.; Mayfield, Stephen P.

2014-01-01

Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for “molecular pharming” in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae could be poised to become the next candidate in recombinant subunit vaccine production, as they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered – from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and systemic immune reactivity. PMID:24596570

Recombination in hepatitis C virus.

Science.gov (United States)

González-Candelas, Fernando; López-Labrador, F Xavier; Bracho, María Alma

2011-10-01

Hepatitis C virus (HCV) is a Flavivirus with a positive-sense, single-stranded RNA genome of about 9,600 nucleotides. It is a major cause of liver disease, infecting almost 200 million people all over the world. Similarly to most RNA viruses, HCV displays very high levels of genetic diversity which have been used to differentiate six major genotypes and about 80 subtypes. Although the different genotypes and subtypes share basic biological and pathogenic features they differ in clinical outcomes, response to treatment and epidemiology. The first HCV recombinant strain, in which different genome segments derived from parentals of different genotypes, was described in St. Petersburg (Russia) in 2002. Since then, there have been only a few more than a dozen reports including descriptions of HCV recombinants at all levels: between genotypes, between subtypes of the same genotype and even between strains of the same subtype. Here, we review the literature considering the reasons underlying the difficulties for unequivocally establishing recombination in this virus along with the analytical methods necessary to do it. Finally, we analyze the potential consequences, especially in clinical practice, of HCV recombination in light of the coming new therapeutic approaches against this virus.

Algae-based oral recombinant vaccines

Directory of Open Access Journals (Sweden)

Elizabeth A Specht

2014-02-01

Full Text Available Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for molecular pharming in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae are poised to become the next candidate in recombinant subunit vaccine production, and they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally-delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered – from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and system immune reactivity.

Chronic intestinal pseudo-obstruction associated with enteric ganglionitis in a Persian cat

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Jeremy Mortier

2016-06-01

Full Text Available Case summary A 7-year-old neutered male Persian cat was presented for acute vomiting and inappetence. Physical examination revealed severe abdominal distension. Radiographs demonstrated pneumoperitoneum, megaoesophagus and generalised gaseous distension of the digestive tract. Exploratory coeliotomy was performed, revealing markedly distended and thickened small and large intestines with no observable peristalsis. No intestinal perforation was present. Bacteriological and cytological analysis of abdominal fluid revealed a septic peritonitis involving Pasteurella multocida . Full-thickness intestinal biopsies demonstrated lymphocytic ganglioneuritis localised to the enteric nervous system, in association with glandular atrophy and muscular layer hypertrophy. Amoxicillin-clavulanate and analgesics were given. The cat’s general condition gradually improved after the addition of pyridostigmine bromide (0.5 mg/kg q12h PO, initiated 3 days postsurgery. Vomiting resolved and did not recur. Follow-up radiographs at 15 days, and 1 and 6 months showed persistent intestinal ileus, milder than on the pretreatment radiographs. Thirty months after presentation the cat is still alive, without clinical signs, and receives 1 mg/kg q12h pyridostigmine. Relevance and novel information To our knowledge, this is the first case of ganglioneuritis of the myenteric plexus described in cats, as well as the first one successfully treated with pyridostigmine. Chronic intestinal pseudo-obstruction is a very rare condition in cats but should be included in the differential diagnosis of generalised gastrointestinal ileus.

Isolation and Antibiogram of Aerobic Nasal Bacterial Flora of Apparently Healthy West African Dwarf Goats

Directory of Open Access Journals (Sweden)

B. O. Emikpe

2009-01-01

Full Text Available Goats are important in the livestock economy by their adaptability to adverse environmental conditions as they are good sources of protein and income for the rural poor. Studies conducted on the bacterial flora of the respiratory tract in goats focused on the pneumonic lungs, with fewer studies on the apparently normal nasal passage and antibiogram of isolated organisms. This study was carried out on 60 apparently healthy West African Dwarf goats. The nasal swab from each goat was analyzed using standard methods. The disc diffusion technique was used for the antibiotic sensitivity test. Three hundred and twenty-eight isolates were obtained. The most frequently isolated species was Streptococcus spp., while Escherichia coli and Staphylococcus aureus were the second dominant bacteria. Other species were isolated at relatively lower rates. The isolation of Mannheimia haemolytica and Pasteurella multocida from the nasal cavity of apparently healthy goats in this study reflects their possible role in most common respiratory diseases encountered in small ruminants. Most of the bacteria were found to be susceptible to streptomycin, quinolones (perfloxacin, ciprofloxacin and ofloxacin and gentamicin, while they were resistant to tetracycline, augmentin and erythromycin. This study shows the relationship between misuse or unrestricted use of antibiotics and drug resistance. Therefore, there is a need for practitioners and researchers to be informed of the appropriate antibiotics to be used in respiratory infections and during control programs.

Chronic intestinal pseudo-obstruction associated with enteric ganglionitis in a Persian cat.

Science.gov (United States)

Mortier, Jeremy; Elissalt, Estelle; Palierne, Sophie; Semin, Marie Odile; Delverdier, Maxence; Diquélou, Armelle

2016-01-01

Case summary A 7-year-old neutered male Persian cat was presented for acute vomiting and inappetence. Physical examination revealed severe abdominal distension. Radiographs demonstrated pneumoperitoneum, megaoesophagus and generalised gaseous distension of the digestive tract. Exploratory coeliotomy was performed, revealing markedly distended and thickened small and large intestines with no observable peristalsis. No intestinal perforation was present. Bacteriological and cytological analysis of abdominal fluid revealed a septic peritonitis involving Pasteurella multocida . Full-thickness intestinal biopsies demonstrated lymphocytic ganglioneuritis localised to the enteric nervous system, in association with glandular atrophy and muscular layer hypertrophy. Amoxicillin-clavulanate and analgesics were given. The cat's general condition gradually improved after the addition of pyridostigmine bromide (0.5 mg/kg q12h PO), initiated 3 days postsurgery. Vomiting resolved and did not recur. Follow-up radiographs at 15 days, and 1 and 6 months showed persistent intestinal ileus, milder than on the pretreatment radiographs. Thirty months after presentation the cat is still alive, without clinical signs, and receives 1 mg/kg q12h pyridostigmine. Relevance and novel information To our knowledge, this is the first case of ganglioneuritis of the myenteric plexus described in cats, as well as the first one successfully treated with pyridostigmine. Chronic intestinal pseudo-obstruction is a very rare condition in cats but should be included in the differential diagnosis of generalised gastrointestinal ileus.

Quantification and characterization of enzymatically produced hyaluronan with fluorophore-assisted carbohydrate electrophoresis.

Science.gov (United States)

Kooy, Floor K; Ma, Muyuan; Beeftink, Hendrik H; Eggink, Gerrit; Tramper, Johannes; Boeriu, Carmen G

2009-01-15

Hyaluronan (HA) is a polysaccharide with high-potential medical applications, depending on the chain length and the chain length distribution. Special interest goes to homogeneous HA oligosaccharides, which can be enzymatically produced using Pasteurella multocida hyaluronan synthase (PmHAS). We have developed a sensitive, simple, and fast method, based on fluorophore-assisted carbohydrate electrophoresis (FACE), for characterization and quantification of polymerization products. A chromatographic pure fluorescent template was synthesized from HA tetrasaccharide (HA4) and 2-aminobenzoic acid. HA4-fluor and HA4 were used as template for PmHAS-mediated polymerization of nucleotide sugars. All products, fluorescent and nonfluorescent, were analyzed with gel electrophoresis and quantified using lane densitometry. Comparison of HA4- and HA4-fluor-derived polymers showed that the fluorophore did not negatively influence the PmHAS-mediated polymerization. Only even-numbered oligosaccharide products were observed using HA4-fluor or HA4 as template. The fluorophore intensity was linearly related to its concentration, and the limit of detection was determined to be 7.4pmol per product band. With this assay, we can now differentiate oligosaccharides of size range DP2 (degree of polymerization 2) to approximately DP400, monitor the progress of polymerization reactions, and measure subtle differences in polymerization rate. Quantifying polymerization products enables us to study the influence of experimental conditions on HA synthesis.

Serologic survey for selected arboviruses and other potential pathogens in wildlife from Mexico.

Science.gov (United States)

Aguirre, A A; McLean, R G; Cook, R S; Quan, T J

1992-07-01

During 1988 and 1989, a serologic survey of wildlife was conducted in northeastern Mexico to determine the presence, prevalence, and distribution of arboviruses and other selected disease agents. Eighty mammal specimens were tested. Antibodies to vesicular stomatitis-Indiana, Venezuelan equine encephalitis-Mena II, Rio Grande virus, and vesicular stomatitis-New Jersey were detected predominantly in small mammals. Deer and mouflon (Ovis musimon) had antibodies to bluetongue and epizootic hemorrhagic disease. Two species had serologic evidence of recent exposure to Francisella tularensis. A white-tailed deer (Odocoileus virginianus) had antibodies to Anaplasma marginale. All specimens tested for antibodies against Yersinia pestis and Brucella abortus were negative. Sera from 315 birds were tested for antibody against five equine encephalitis viruses and six avian pathogens. During 1988, antibodies to Venezuelan equine encephalitis-Mena II, Venezuelan equine encephalitis-TC83, St. Louis encephalitis, eastern equine encephalitis, and western equine encephalitis were detected in birds of several species. Antibodies to Pasteurella multocida and Newcastle disease virus were also detected. Birds from five species presented antibodies to Mycoplasma meleagridis. Specimens tested for M. gallisepticum, M. synoviae, and Chlamydia psittaci were negative. To the best of our knowledge, this survey represents the first serologic evidence of bluetongue, Cache Valley virus, epizootic hemorrhagic disease, Jamestown Canyon virus, vesicular stomatitis-Indiana, vesicular stomatitis-New Jersey, Rio Grande virus, and tularemia reported among wildlife in Mexico.

Enhanced defects recombination in ion irradiated SiC

International Nuclear Information System (INIS)

Izzo, G.; Litrico, G.; Grassia, F.; Calcagno, L.; Foti, G.

2010-01-01

Point defects induced in SiC by ion irradiation show a recombination at temperatures as low as 320 K and this process is enhanced after running current density ranging from 80 to 120 A/cm 2 . Ion irradiation induces in SiC the formation of different defect levels and low-temperature annealing changes their concentration. Some levels (S 0 , S x and S 2 ) show a recombination and simultaneously a new level (S 1 ) is formed. An enhanced recombination of defects is besides observed after running current in the diode at room temperature. The carriers introduction reduces the S 2 trap concentration, while the remaining levels are not modified. The recombination is negligible up to a current density of 50 A/cm 2 and increases at higher current density. The enhanced recombination of the S 2 trap occurs at 300 K, which otherwise requires a 400 K annealing temperature. The process can be related to the electron-hole recombination at the associated defect.

PROGENITORS OF RECOMBINING SUPERNOVA REMNANTS

Energy Technology Data Exchange (ETDEWEB)

Moriya, Takashi J., E-mail: takashi.moriya@ipmu.jp [Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8583 (Japan)

2012-05-01

Usual supernova remnants have either ionizing plasma or plasma in collisional ionization equilibrium, i.e., the ionization temperature is lower than or equal to the electron temperature. However, the existence of recombining supernova remnants, i.e., supernova remnants with ionization temperature higher than the electron temperature, has been recently confirmed. One suggested way to have recombining plasma in a supernova remnant is to have a dense circumstellar medium at the time of the supernova explosion. If the circumstellar medium is dense enough, collisional ionization equilibrium can be established in the early stage of the evolution of the supernova remnant and subsequent adiabatic cooling, which occurs after the shock wave gets out of the dense circumstellar medium, makes the electron temperature lower than the ionization temperature. We study the circumstellar medium around several supernova progenitors and show which supernova progenitors can have a circumstellar medium dense enough to establish collisional ionization equilibrium soon after the explosion. We find that the circumstellar medium around red supergiants (especially massive ones) and the circumstellar medium dense enough to make Type IIn supernovae can establish collisional ionization equilibrium soon after the explosion and can evolve to become recombining supernova remnants. Wolf-Rayet stars and white dwarfs have the possibility to be recombining supernova remnants but the fraction is expected to be very small. As the occurrence rate of the explosions of red supergiants is much higher than that of Type IIn supernovae, the major progenitors of recombining supernova remnants are likely to be red supergiants.

Dissociation of recombinant prion autocatalysis from infectivity.

Science.gov (United States)

Noble, Geoffrey P; Supattapone, Surachai

2015-01-01

Within the mammalian prion field, the existence of recombinant prion protein (PrP) conformers with self-replicating (ie. autocatalytic) activity in vitro but little to no infectious activity in vivo challenges a key prediction of the protein-only hypothesis of prion replication--that autocatalytic PrP conformers should be infectious. To understand this dissociation of autocatalysis from infectivity, we recently performed a structural and functional comparison between a highly infectious and non-infectious pair of autocatalytic recombinant PrP conformers derived from the same initial prion strain. (1) We identified restricted, C-terminal structural differences between these 2 conformers and provided evidence that these relatively subtle differences prevent the non-infectious conformer from templating the conversion of native PrP(C) substrates containing a glycosylphosphatidylinositol (GPI) anchor. (1) In this article we discuss a model, consistent with these findings, in which recombinant PrP, lacking post-translational modifications and associated folding constraints, is capable of adopting a wide variety of autocatalytic conformations. Only a subset of these recombinant conformers can be adopted by post-translationally modified native PrP(C), and this subset represents the recombinant conformers with high specific infectivity. We examine this model's implications for the generation of highly infectious recombinant prions and the protein-only hypothesis of prion replication.

Recombiner

International Nuclear Information System (INIS)

Saalfrank, H.

1985-01-01

Air containing hydrogen can be oxidized by heating in a container called a recombiner, in order to avoid the collection of hydrogen. The container is long and a large number of straight heating bars are arranged in parallel in it and they are flanged to a lid. The heating bars are surrounded by tubes, in order to obtain good heat transfer by a narrow annular gap. (orig.) [de

Anti-proliferative activity of recombinant melittin expressed in ...

African Journals Online (AJOL)

Recombinant melittin was then successfully expressed in Escherichia coli. The activity of affinity-purified recombinant melittin was determined in human leukemic U937 cells. Results show that the recombinant melittin had the same anti-proliferative activity in human leukemic U937 cells in vitro as natural one. This shows the ...

Site directed recombination

Science.gov (United States)

Jurka, Jerzy W.

1997-01-01

Enhanced homologous recombination is obtained by employing a consensus sequence which has been found to be associated with integration of repeat sequences, such as Alu and ID. The consensus sequence or sequence having a single transition mutation determines one site of a double break which allows for high efficiency of integration at the site. By introducing single or double stranded DNA having the consensus sequence flanking region joined to a sequence of interest, one can reproducibly direct integration of the sequence of interest at one or a limited number of sites. In this way, specific sites can be identified and homologous recombination achieved at the site by employing a second flanking sequence associated with a sequence proximal to the 3'-nick.

Recombination and dissociative recombination of H2+ and H3+ ions on surfaces with application to hydrogen negative ion sources

International Nuclear Information System (INIS)

Hiskes, J.R.; Karo, A.M.

1988-12-01

A four-step model for recombination and dissociative recombination of H 2 + and H 3 + ions on metal surfaces is discussed. Vibrationally excited molecules, H 2 (v''), from H 3 + recombination are produced in a broad spectrum that enhances the excited level distribution. The application of this latter process to hydrogen negative ion discharges is discussed. 5 refs., 3 figs., 1 tab

Recombination rate variation in mice from an isolated island.

Science.gov (United States)

Wang, Richard J; Gray, Melissa M; Parmenter, Michelle D; Broman, Karl W; Payseur, Bret A

2017-01-01

Recombination rate is a heritable trait that varies among individuals. Despite the major impact of recombination rate on patterns of genetic diversity and the efficacy of selection, natural variation in this phenotype remains poorly characterized. We present a comparison of genetic maps, sampling 1212 meioses, from a unique population of wild house mice (Mus musculus domesticus) that recently colonized remote Gough Island. Crosses to a mainland reference strain (WSB/EiJ) reveal pervasive variation in recombination rate among Gough Island mice, including subchromosomal intervals spanning up to 28% of the genome. In spite of this high level of polymorphism, the genomewide recombination rate does not significantly vary. In general, we find that recombination rate varies more when measured in smaller genomic intervals. Using the current standard genetic map of the laboratory mouse to polarize intervals with divergent recombination rates, we infer that the majority of evolutionary change occurred in one of the two tested lines of Gough Island mice. Our results confirm that natural populations harbour a high level of recombination rate polymorphism and highlight the disparities in recombination rate evolution across genomic scales. © 2016 John Wiley & Sons Ltd.

Live recombinant BHV/BRSV vaccine

OpenAIRE

Keil, G.M.; Rijsewijk, F.A.M.

1998-01-01

The present invention refers to synthetic Bovine Respiratory Syncytium virus genes. Also the invention relates to live attenuated Bovine Herpesvirus recombinants carrying such synthetic genes. Furthermore, the invention relates to vaccines based on these live attenuated recombinants, for the protection of cattle against both Bovine herpesvirus infection and against Bovine Respiratory Syncytium virus infection. Also the invention relates to methods for the preparation of such live attenuated r...

Recombinant snake venom prothrombin activators

OpenAIRE

L?vgren, Ann

2012-01-01

Three prothrombin activators; ecarin, which was originally isolated from the venom of the saw-scaled viper Echis carinatus, trocarin from the rough-scaled snake Tropidechis carinatus, and oscutarin from the Taipan snake Oxyuranus scutellatus, were expressed in mammalian cells with the purpose to obtain recombinant prothrombin activators that could be used to convert prothrombin to thrombin. We have previously reported that recombinant ecarin can efficiently generate thrombin without the need ...

Electronic recombination in some physics problems

International Nuclear Information System (INIS)

Guzman, O.

1988-01-01

This work is related to calculations of electronic recombination rates, as a function of electronic density, electronic temperature, and ion nuclear charge. Recombination times can be calculated and compared to cooling time, in cooling processes of ion beans by electrons from storage rings. (A.C.A.S.) [pt

Expression and purification of recombinant hemoglobin in Escherichia coli.

Directory of Open Access Journals (Sweden)

Chandrasekhar Natarajan

Full Text Available Recombinant DNA technologies have played a pivotal role in the elucidation of structure-function relationships in hemoglobin (Hb and other globin proteins. Here we describe the development of a plasmid expression system to synthesize recombinant Hbs in Escherichia coli, and we describe a protocol for expressing Hbs with low intrinsic solubilities. Since the α- and β-chain Hbs of different species span a broad range of solubilities, experimental protocols that have been optimized for expressing recombinant human HbA may often prove unsuitable for the recombinant expression of wildtype and mutant Hbs of other species.As a test case for our expression system, we produced recombinant Hbs of the deer mouse (Peromyscus maniculatus, a species that has been the subject of research on mechanisms of Hb adaptation to hypoxia. By experimentally assessing the combined effects of induction temperature, induction time and E. coli expression strain on the solubility of recombinant deer mouse Hbs, we identified combinations of expression conditions that greatly enhanced the yield of recombinant protein and which also increased the efficiency of post-translational modifications.Our protocol should prove useful for the experimental study of recombinant Hbs in many non-human animals. One of the chief advantages of our protocol is that we can express soluble recombinant Hb without co-expressing molecular chaperones, and without the need for additional reconstitution or heme-incorporation steps. Moreover, our plasmid construct contains a combination of unique restriction sites that allows us to produce recombinant Hbs with different α- and β-chain subunit combinations by means of cassette mutagenesis.

Expression and purification of recombinant hemoglobin in Escherichia coli.

Science.gov (United States)

Natarajan, Chandrasekhar; Jiang, Xiaoben; Fago, Angela; Weber, Roy E; Moriyama, Hideaki; Storz, Jay F

2011-01-01

Recombinant DNA technologies have played a pivotal role in the elucidation of structure-function relationships in hemoglobin (Hb) and other globin proteins. Here we describe the development of a plasmid expression system to synthesize recombinant Hbs in Escherichia coli, and we describe a protocol for expressing Hbs with low intrinsic solubilities. Since the α- and β-chain Hbs of different species span a broad range of solubilities, experimental protocols that have been optimized for expressing recombinant human HbA may often prove unsuitable for the recombinant expression of wildtype and mutant Hbs of other species. As a test case for our expression system, we produced recombinant Hbs of the deer mouse (Peromyscus maniculatus), a species that has been the subject of research on mechanisms of Hb adaptation to hypoxia. By experimentally assessing the combined effects of induction temperature, induction time and E. coli expression strain on the solubility of recombinant deer mouse Hbs, we identified combinations of expression conditions that greatly enhanced the yield of recombinant protein and which also increased the efficiency of post-translational modifications. Our protocol should prove useful for the experimental study of recombinant Hbs in many non-human animals. One of the chief advantages of our protocol is that we can express soluble recombinant Hb without co-expressing molecular chaperones, and without the need for additional reconstitution or heme-incorporation steps. Moreover, our plasmid construct contains a combination of unique restriction sites that allows us to produce recombinant Hbs with different α- and β-chain subunit combinations by means of cassette mutagenesis.

Expression and purification of recombinant hemoglobin in Escherichia coli

DEFF Research Database (Denmark)

Natarajan, Chandrasekhar; Jiang, Xiaoben; Fago, Angela

2011-01-01

BACKGROUND: Recombinant DNA technologies have played a pivotal role in the elucidation of structure-function relationships in hemoglobin (Hb) and other globin proteins. Here we describe the development of a plasmid expression system to synthesize recombinant Hbs in Escherichia coli, and we describe...... a protocol for expressing Hbs with low intrinsic solubilities. Since the alpha- and beta-chain Hbs of different species span a broad range of solubilities, experimental protocols that have been optimized for expressing recombinant human HbA may often prove unsuitable for the recombinant expression......-translational modifications. CONCLUSION/SIGNIFICANCE: Our protocol should prove useful for the experimental study of recombinant Hbs in many non-human animals. One of the chief advantages of our protocol is that we can express soluble recombinant Hb without co-expressing molecular chaperones, and without the need...

Bayesian inference of shared recombination hotspots between humans and chimpanzees.

Science.gov (United States)

Wang, Ying; Rannala, Bruce

2014-12-01

Recombination generates variation and facilitates evolution. Recombination (or lack thereof) also contributes to human genetic disease. Methods for mapping genes influencing complex genetic diseases via association rely on linkage disequilibrium (LD) in human populations, which is influenced by rates of recombination across the genome. Comparative population genomic analyses of recombination using related primate species can identify factors influencing rates of recombination in humans. Such studies can indicate how variable hotspots for recombination may be both among individuals (or populations) and over evolutionary timescales. Previous studies have suggested that locations of recombination hotspots are not conserved between humans and chimpanzees. We made use of the data sets from recent resequencing projects and applied a Bayesian method for identifying hotspots and estimating recombination rates. We also reanalyzed SNP data sets for regions with known hotspots in humans using samples from the human and chimpanzee. The Bayes factors (BF) of shared recombination hotspots between human and chimpanzee across regions were obtained. Based on the analysis of the aligned regions of human chromosome 21, locations where the two species show evidence of shared recombination hotspots (with high BFs) were identified. Interestingly, previous comparative studies of human and chimpanzee that focused on the known human recombination hotspots within the β-globin and HLA regions did not find overlapping of hotspots. Our results show high BFs of shared hotspots at locations within both regions, and the estimated locations of shared hotspots overlap with the locations of human recombination hotspots obtained from sperm-typing studies. Copyright © 2014 by the Genetics Society of America.

Effects of the rad52 gene on recombination in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Prakash, S.; Prakash, L.; Burke, W.; Montelone, B.A.

1979-01-01

Effects of the rad52 mutation in Saccharomyces cerevisiae on meiotic, γ-ray-induced, uv-induced, and spontaneous mitotic recombination were studied. The rad52/rad52 diploids undergo premeiotic DNA synthesis; sporulation occurs but inviable spores are produced. Intra- and intergenic recombination during meiosis were examined in cells transferred from sporulation medium to vegetative medium at different time intervals. No intragenic recombination was observed at the hisl-1/hisl-315 and trp5-2/trp5-48 heteroalleles. Gene-centromere recombination was also not observed in rad52/rad52 diploids. No γ-ray-induced intragenic mitotic recombination is seen in rad52/rad52 diploids and uv-induced intragenic recombination is greatly reduced. However, spontaneous mitotic recombination is not similarly affected. The RAD52 gene thus functions in recombination in meiosis and in γ-ray and uv-induced mitotic recombination but not in spontaneous mitotic recombination

Heterogeneous recombination among Hepatitis B virus genotypes.

Science.gov (United States)

Castelhano, Nadine; Araujo, Natalia M; Arenas, Miguel

2017-10-01

The rapid evolution of Hepatitis B virus (HBV) through both evolutionary forces, mutation and recombination, allows this virus to generate a large variety of adapted variants at both intra and inter-host levels. It can, for instance, generate drug resistance or the diverse viral genotypes that currently exist in the HBV epidemics. Concerning the latter, it is known that recombination played a major role in the emergence and genetic diversification of novel genotypes. In this regard, the quantification of viral recombination in each genotype can provide relevant information to devise expectations about the evolutionary trends of the epidemic. Here we measured the amount of this evolutionary force by estimating global and local recombination rates in >4700 HBV complete genome sequences corresponding to nine (A to I) HBV genotypes. Counterintuitively, we found that genotype E presents extremely high levels of recombination, followed by genotypes B and C. On the other hand, genotype G presents the lowest level, where recombination is almost negligible. We discuss these findings in the light of known characteristics of these genotypes. Additionally, we present a phylogenetic network to depict the evolutionary history of the studied HBV genotypes. This network clearly classified all genotypes into specific groups and indicated that diverse pairs of genotypes are derived from a common ancestor (i.e., C-I, D-E and, F-H) although still the origin of this virus presented large uncertainty. Altogether we conclude that the amount of observed recombination is heterogeneous among HBV genotypes and that this heterogeneity can influence on the future expansion of the epidemic. Copyright © 2017 Elsevier B.V. All rights reserved.

Graded Recombination Layers for Multijunction Photovoltaics

KAUST Repository

Koleilat, Ghada I.

2012-06-13

Multijunction devices consist of a stack of semiconductor junctions having bandgaps tuned across a broad spectrum. In solar cells this concept is used to increase the efficiency of photovoltaic harvesting, while light emitters and detectors use it to achieve multicolor and spectrally tunable behavior. In series-connected current-matched multijunction devices, the recombination layers must allow the hole current from one cell to recombine, with high efficiency and low voltage loss, with the electron current from the next cell. We recently reported a tandem solar cell in which the recombination layer was implemented using a progression of n-type oxides whose doping densities and work functions serve to connect, with negligible resistive loss at solar current densities, the constituent cells. Here we present the generalized conditions for design of efficient graded recombination layer solar devices. We report the number of interlayers and the requirements on work function and doping of each interlayer, to bridge an work function difference as high as 1.6 eV. We also find solutions that minimize the doping required of the interlayers in order to minimize optical absorption due to free carriers in the graded recombination layer (GRL). We demonstrate a family of new GRL designs experimentally and highlight the benefits of the progression of dopings and work functions in the interlayers. © 2012 American Chemical Society.

Review of Parton Recombination Models

International Nuclear Information System (INIS)

Bass, Steffen A

2006-01-01

Parton recombination models have been very successful in explaining data taken at RHIC on hadron spectra and emission patterns in Au+Au collisions at transverse momenta above 2 GeV/c, which have exhibited features which could not be understood in the framework of basic perturbative QCD. In this article I will review the current status on recombination models and outline which future challenges need to be addressed by this class of models

The model of recombination process in TlBr

International Nuclear Information System (INIS)

Grigorjeva, L.; Millers, D.

2002-01-01

The time-resolved luminescence was used as a tool in the study of recombination process in several undoped TlBr crystals. The spectra and decay kinetics observed under electron beam excitation were investigated. Observation of several luminescence bands with different decay rates shows that more than one recombination center is involved and the recombination process is quite complicated. The band at ∼2.5 eV is dominant under 10 ns excitation pulse (electron beam or nitrogen laser pulses). The results of short-lived absorption and luminescence are used for analysis of possible mechanisms of recombination processes in TlBr

Affinity purification of recombinant human plasminogen activator ...

African Journals Online (AJOL)

Affinity purification of recombinant human plasminogen activator from ... Screening antibody was performed using rhPA milk in an ELISA-elution assay. ... useful for purifying other tPA mutants or other novel recombinant milkderived proteins.

Recombinant human bone morphogenetic protein induces bone formation

International Nuclear Information System (INIS)

Wang, E.A.; Rosen, V.; D'Alessandro, J.S.; Bauduy, M.; Cordes, P.; Harada, T.; Israel, D.I.; Hewick, R.M.; Kerns, K.M.; LaPan, P.; Luxenberg, D.P.; McQuaid, D.; Moutsatsos, I.K.; Nove, J.; Wozney, J.M.

1990-01-01

The authors have purified and characterized active recombinant human bone morphogenetic protein (BMP) 2A. Implantation of the recombinant protein in rats showed that a single BMP can induce bone formation in vivo. A dose-response and time-course study using the rat ectopic bone formation assay revealed that implantation of 0.5-115 μg of partially purified recombinant human BMP-2A resulted in cartilage by day 7 and bone formation by day 14. The time at which bone formation occurred was dependent on the amount of BMP-2A implanted; at high doses bone formation could be observed at 5 days. The cartilage- and bone-inductive activity of the recombinant BMP-2A is histologically indistinguishable from that of bone extracts. Thus, recombinant BMP-2A has therapeutic potential to promote de novo bone formation in humans

Inference of Ancestral Recombination Graphs through Topological Data Analysis

Science.gov (United States)

Cámara, Pablo G.; Levine, Arnold J.; Rabadán, Raúl

2016-01-01

The recent explosion of genomic data has underscored the need for interpretable and comprehensive analyses that can capture complex phylogenetic relationships within and across species. Recombination, reassortment and horizontal gene transfer constitute examples of pervasive biological phenomena that cannot be captured by tree-like representations. Starting from hundreds of genomes, we are interested in the reconstruction of potential evolutionary histories leading to the observed data. Ancestral recombination graphs represent potential histories that explicitly accommodate recombination and mutation events across orthologous genomes. However, they are computationally costly to reconstruct, usually being infeasible for more than few tens of genomes. Recently, Topological Data Analysis (TDA) methods have been proposed as robust and scalable methods that can capture the genetic scale and frequency of recombination. We build upon previous TDA developments for detecting and quantifying recombination, and present a novel framework that can be applied to hundreds of genomes and can be interpreted in terms of minimal histories of mutation and recombination events, quantifying the scales and identifying the genomic locations of recombinations. We implement this framework in a software package, called TARGet, and apply it to several examples, including small migration between different populations, human recombination, and horizontal evolution in finches inhabiting the Galápagos Islands. PMID:27532298

Retroviral Vectors for Analysis of Viral Mutagenesis and Recombination

Directory of Open Access Journals (Sweden)

Jonathan M.O. Rawson

2014-09-01

Full Text Available Retrovirus population diversity within infected hosts is commonly high due in part to elevated rates of replication, mutation, and recombination. This high genetic diversity often complicates the development of effective diagnostics, vaccines, and antiviral drugs. This review highlights the diverse vectors and approaches that have been used to examine mutation and recombination in retroviruses. Retroviral vectors for these purposes can broadly be divided into two categories: those that utilize reporter genes as mutation or recombination targets and those that utilize viral genes as targets of mutation or recombination. Reporter gene vectors greatly facilitate the detection, quantification, and characterization of mutants and/or recombinants, but may not fully recapitulate the patterns of mutagenesis or recombination observed in native viral gene sequences. In contrast, the detection of mutations or recombination events directly in viral genes is more biologically relevant but also typically more challenging and inefficient. We will highlight the advantages and disadvantages of the various vectors and approaches used as well as propose ways in which they could be improved.

Hadron production at RHIC: recombination of quarks

Energy Technology Data Exchange (ETDEWEB)

Fries, Rainer J [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2005-01-01

We discuss quark recombination applied to the hadronization of a quark gluon plasma. It has been shown that the quark recombination model can explain essential features of hadron production measured in high energy heavy ion collisions.

Catalytic hydrogen recombination for nuclear containments

International Nuclear Information System (INIS)

Koroll, G.W.; Lau, D.W.P.; Dewit, W.A.; Graham, W.R.C.

1994-01-01

Catalytic recombiners appear to be a credible option for hydrogen mitigation in nuclear containments. The passive operation, versatility and ease of back fitting are appealing for existing stations and new designs. Recently, a generation of wet-proofed catalyst materials have been developed at AECL which are highly specific to H 2 -O 2 , are active at ambient temperatures and are being evaluated for containment applications. Two types of catalytic recombiners were evaluated for hydrogen removal in containments based on the AECL catalyst. The first is a catalytic combustor for application in existing air streams such as provided by fans or ventilation systems. The second is an autocatalytic recombiner which uses the enthalpy of reaction to produce natural convective flow over the catalyst elements. Intermediate-scale results obtained in 6 m 3 and 10 m 3 spherical and cylindrical vessels are given to demonstrate self-starting limits, operating limits, removal capacity, scaling parameters, flow resistance, mixing behaviour in the vicinity of an operating recombiner and sensitivity to poisoning, fouling and radiation. (author). 13 refs., 10 figs

Pericardite em suínos ao abate no Rio Grande Sul: avaliação de agentes bacterianos e lesões associadas

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Carolini F. Coelho

2014-07-01

Full Text Available O objetivo do presente estudo foi identificar a frequência de lesões macroscópicas e microscópicas e dos agentes bacterianos envolvidos em pericardites em suínos no abate no Estado do Rio Grande do Sul. As amostras foram coletadas em frigoríficos de suínos com Serviço de Inspeção Federal (SIF entre fevereiro a outubro de 2010 e a condenação por pericardite dos animais acompanhados foi de 3,9% (299/7.571. No total foram investigados 91 casos de pericardites, 89% deles foram classificados como crônicos por histopatologia e pleurite crônica foi observada em 47% dos pulmões correspondentes, todavia não houve associação significativa entre as duas lesões. Os agentes bacterianos isolados a partir dos corações foram Streptococcus spp., Pasteurella multocida, Haemophilus parasuis e Streptococcus suis. DNA bacterianos mais detectados pela PCR foram de Mycoplasma hyopneumoniae e Actinobacillus pleuropneumoniae. Houve associação significativa entre isolamento de P. multocida e Streptococcus sp. nos corações e pulmões correspondentes. Esses resultados sugerem que a infecção no pulmão possa ter servido de porta de entrada para a colonização do pericárdio adjacente. Apesar de M. hyopneumoniae ter sido o agente detectado com maior frequência pela PCR em corações e pulmões correspondentes, não houve associação significativa da detecção dos agentes nos órgãos. Isto sugere que as infecções foram eventos independentes. Os demais agentes investigados não apresentaram associação significativa entre isolamento ou detecção de DNA em coração e pulmão correspondente. Outro achado importante foi a presença de coinfecções bacterianas em 2% dos corações e por PCR foi detectado DNA bacteriano de dois ou mais agentes em 16,5% dos corações. Esses resultados sugerem que as coinfecções em pericardites precisam ser melhor estudadas.

Recombination Processes and Nonlinear Markov Chains.

Science.gov (United States)

Pirogov, Sergey; Rybko, Alexander; Kalinina, Anastasia; Gelfand, Mikhail

2016-09-01

Bacteria are known to exchange genetic information by horizontal gene transfer. Since the frequency of homologous recombination depends on the similarity between the recombining segments, several studies examined whether this could lead to the emergence of subspecies. Most of them simulated fixed-size Wright-Fisher populations, in which the genetic drift should be taken into account. Here, we use nonlinear Markov processes to describe a bacterial population evolving under mutation and recombination. We consider a population structure as a probability measure on the space of genomes. This approach implies the infinite population size limit, and thus, the genetic drift is not assumed. We prove that under these conditions, the emergence of subspecies is impossible.

[Construction and expression of a recombinant adenovirus with LZP3].

Science.gov (United States)

Chen, Bang-dang; Zhang, Fu-chun; Sun, Mei-yu; Li, Yi-jie; Ma, Zheng-hai

2007-08-01

To explore a new immunocontraceptive vaccine and construct an attenuated recombinant adenoviral vaccine against Lagurus lagurus zona pellucida 3(LZP3). LZP3 gene was subcloned into the shuttle vector pShuttle-CMV, and then a two-step transformation procedure was employed to construct a recombinant adenoviral plasmid with LZP3, which was digested with Pac I and transfected into HEK293 cells to package recombinant adenovirus particles. Finally, HeLa cells were infected by the recombinant adenovirus. LZP3 gene was detected from the recombinant virus by PCR, and its transcription and expression were analyzed by RT-PCR and Western blot. Recombinant adenovirus vector pAd-LZP3 with LZP3 gene was constructed by homologous recombination in E.coli, and a recombinant adenovirus was obtained by transfecting HEK293 cells with pAd-LZP3. PCR test indicated that LZP3 gene was successfully integrated into the adenoviral genome, and the titer of the recombinant adenovirus reached 1.2x10(10) pfu/L. The transcription and expression of LZP3 gene in the infected HeLa cells were confirmed by RT-PCR and Western blot. The recombinant adenovirus RAd-LZP3 can be successfully expressed in the infected HeLa cells, which lays the foundation for further researches into immunizing animals with RAd-LZP3.

Genetic characterization of somatic recombination in Trichoderma pseudokoningii

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Barcellos Fernando Gomes

2003-01-01

Full Text Available Crossing experiments via hyphal anastomosis between two strains contrasting for auxotrophic markers of Trichoderma pseudokoningii were conducted to characterize the somatic recombination process in this specie. Four crossings were made and a total of 1052 colonies obtained from conidial suspensions of the heterokaryotic colonies were analyzed. Sixty-eight recombinant colonies, from four growing generations, were analyzed for the auxotrophic markers. Of the 68 colonies analyzed, 58 were stable after four generations and the remainders were unstable, reverting to one of the parentals. Most of the recombinant colonies were unstable through subculture and after four growing generations they showed the leu ino met markers (auxotrophic for leucin, inositol and metionin respectively. The unstable recombinant colonies showed irregular growing borders, sparse sporulation and frequent sector formation. The results suggest the occurrence of recombination mechanisms in the heterokaryon (somatic recombination, different from those described for the parasexual cycle or parameiosis. Therefore, we proposed the ocurrence of nuclei degradation from one parental (non prevalent parental in the heterokaryon and that the resulting chromosomal fragments may be incorporated into whole nuclei of the another parental (prevalent parental. However the parameiosis as originally described cannot be excluded.

Variation in Recombination Rate and Its Genetic Determinism in Sheep Populations.

Science.gov (United States)

Petit, Morgane; Astruc, Jean-Michel; Sarry, Julien; Drouilhet, Laurence; Fabre, Stéphane; Moreno, Carole R; Servin, Bertrand

2017-10-01

Recombination is a complex biological process that results from a cascade of multiple events during meiosis. Understanding the genetic determinism of recombination can help to understand if and how these events are interacting. To tackle this question, we studied the patterns of recombination in sheep, using multiple approaches and data sets. We constructed male recombination maps in a dairy breed from the south of France (the Lacaune breed) at a fine scale by combining meiotic recombination rates from a large pedigree genotyped with a 50K SNP array and historical recombination rates from a sample of unrelated individuals genotyped with a 600K SNP array. This analysis revealed recombination patterns in sheep similar to other mammals but also genome regions that have likely been affected by directional and diversifying selection. We estimated the average recombination rate of Lacaune sheep at 1.5 cM/Mb, identified ∼50,000 crossover hotspots on the genome, and found a high correlation between historical and meiotic recombination rate estimates. A genome-wide association study revealed two major loci affecting interindividual variation in recombination rate in Lacaune, including the RNF212 and HEI10 genes and possibly two other loci of smaller effects including the KCNJ15 and FSHR genes. The comparison of these new results to those obtained previously in a distantly related population of domestic sheep (the Soay) revealed that Soay and Lacaune males have a very similar distribution of recombination along the genome. The two data sets were thus combined to create more precise male meiotic recombination maps in Sheep. However, despite their similar recombination maps, Soay and Lacaune males were found to exhibit different heritabilities and QTL effects for interindividual variation in genome-wide recombination rates. This highlights the robustness of recombination patterns to underlying variation in their genetic determinism. Copyright © 2017 by the Genetics Society

Evolution of recombination in eutherian mammals: insights into mechanisms that affect recombination rates and crossover interference

OpenAIRE

Segura, Joana; Ferretti, Luca; Ramos-Onsins, Sebastián; Capilla, Laia; Farré, Marta; Reis, Fernanda; Oliver-Bonet, Maria; Fernández-Bellón, Hugo; Garcia, Francisca; Garcia-Caldés, Montserrat; Robinson, Terence J.; Ruiz-Herrera, Aurora

2013-01-01

Recombination allows faithful chromosomal segregation during meiosis and contributes to the production of new heritable allelic variants that are essential for the maintenance of genetic diversity. Therefore, an appreciation of how this variation is created and maintained is of critical importance to our understanding of biodiversity and evolutionary change. Here, we analysed the recombination features from species representing the major eutherian taxonomic groups Afrotheria, Rodentia, Primat...

In vitro V(D)J recombination: signal joint formation.

Science.gov (United States)

Cortes, P; Weis-Garcia, F; Misulovin, Z; Nussenzweig, A; Lai, J S; Li, G; Nussenzweig, M C; Baltimore, D

1996-11-26

The first step of V(D)J recombination, specific cleavage at the recombination signal sequence (RSS), can be carried out by the recombination activating proteins RAG1 and RAG2. In vivo, the cleaved coding and signal ends must be rejoined to generate functional antigen receptors and maintain chromosomal integrity. We have investigated signal joint formation using deletion and inversion substrates in a cell free system. RAG1 and RAG2 alone or in combination were unable to generate signal joints. However, RAG1 and RAG2 complemented with nuclear extracts were able to recombine an extrachromosomal substrate and form precise signal joints. The in vitro reaction resembled authentic V(D)J recombination in being Ku-antigen-dependent.

Recombinant DNA production of spider silk proteins.

Science.gov (United States)

Tokareva, Olena; Michalczechen-Lacerda, Valquíria A; Rech, Elíbio L; Kaplan, David L

2013-11-01

Spider dragline silk is considered to be the toughest biopolymer on Earth due to an extraordinary combination of strength and elasticity. Moreover, silks are biocompatible and biodegradable protein-based materials. Recent advances in genetic engineering make it possible to produce recombinant silks in heterologous hosts, opening up opportunities for large-scale production of recombinant silks for various biomedical and material science applications. We review the current strategies to produce recombinant spider silks. © 2013 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Recombination-Driven Genome Evolution and Stability of Bacterial Species.

Science.gov (United States)

Dixit, Purushottam D; Pang, Tin Yau; Maslov, Sergei

2017-09-01

While bacteria divide clonally, horizontal gene transfer followed by homologous recombination is now recognized as an important contributor to their evolution. However, the details of how the competition between clonality and recombination shapes genome diversity remains poorly understood. Using a computational model, we find two principal regimes in bacterial evolution and identify two composite parameters that dictate the evolutionary fate of bacterial species. In the divergent regime, characterized by either a low recombination frequency or strict barriers to recombination, cohesion due to recombination is not sufficient to overcome the mutational drift. As a consequence, the divergence between pairs of genomes in the population steadily increases in the course of their evolution. The species lacks genetic coherence with sexually isolated clonal subpopulations continuously formed and dissolved. In contrast, in the metastable regime, characterized by a high recombination frequency combined with low barriers to recombination, genomes continuously recombine with the rest of the population. The population remains genetically cohesive and temporally stable. Notably, the transition between these two regimes can be affected by relatively small changes in evolutionary parameters. Using the Multi Locus Sequence Typing (MLST) data, we classify a number of bacterial species to be either the divergent or the metastable type. Generalizations of our framework to include selection, ecologically structured populations, and horizontal gene transfer of nonhomologous regions are discussed as well. Copyright © 2017 by the Genetics Society of America.

Genetic recombination of tick-borne flaviviruses among wild-type strains.

Science.gov (United States)

Norberg, Peter; Roth, Anette; Bergström, Tomas

2013-06-05

Genetic recombination has been suggested to occur in mosquito-borne flaviviruses. In contrast, tick-borne flaviviruses have been thought to evolve in a clonal manner, although recent studies suggest that recombination occurs also for these viruses. We re-analyzed the data and found that previous conclusions on wild type recombination were probably falsely drawn due to misalignments of nucleotide sequences, ambiguities in GenBank sequences, or different laboratory culture histories suggestive of recombination events in laboratory. To evaluate if reliable predictions of wild type recombination of tick-borne flaviviruses can be made, we analyzed viral strains sequenced exclusively for this study, and other flavivirus sequences retrieved from GenBank. We detected genetic signals supporting recombination between viruses within the three clades of TBEV-Eu, TBEV-Sib and TBEV-Fe, respectively. Our results suggest that the tick-borne encephalitis viruses may undergo recombination under natural conditions, but that geographic barriers restrict most recombination events to involve only closely genetically related viruses. Copyright © 2013 Elsevier Inc. All rights reserved.

The influence of recombination on human genetic diversity.

Directory of Open Access Journals (Sweden)

Chris C A Spencer

2006-09-01

Full Text Available In humans, the rate of recombination, as measured on the megabase scale, is positively associated with the level of genetic variation, as measured at the genic scale. Despite considerable debate, it is not clear whether these factors are causally linked or, if they are, whether this is driven by the repeated action of adaptive evolution or molecular processes such as double-strand break formation and mismatch repair. We introduce three innovations to the analysis of recombination and diversity: fine-scale genetic maps estimated from genotype experiments that identify recombination hotspots at the kilobase scale, analysis of an entire human chromosome, and the use of wavelet techniques to identify correlations acting at different scales. We show that recombination influences genetic diversity only at the level of recombination hotspots. Hotspots are also associated with local increases in GC content and the relative frequency of GC-increasing mutations but have no effect on substitution rates. Broad-scale association between recombination and diversity is explained through covariance of both factors with base composition. To our knowledge, these results are the first evidence of a direct and local influence of recombination hotspots on genetic variation and the fate of individual mutations. However, that hotspots have no influence on substitution rates suggests that they are too ephemeral on an evolutionary time scale to have a strong influence on broader scale patterns of base composition and long-term molecular evolution.

Triplet formation in the ion recombination in irradiated liquids

International Nuclear Information System (INIS)

Bartczak, W.M.; Tachiya, M.; Hummel, A.

1990-01-01

The formation of singlet and triplet excited stages in the ion recombination in groups of oppositely charged ions (or positive ions and electrons) in nonpolar liquids, as occurs in the tracks of high energy electrons, is considered. Theoretical studies on triplet formation in groups of ion pairs have thus far concentrated on the case where recombination of the negative ions with any of the positive ions in the group is equally probable (random recombination). In this paper the probability for geminate recombination (electron and parent positive ion) vs cross-recombination (an electron with a positive ion other than its parent ion) in multiple ion pair groups is calculated by computer simulation and the effect of the initial spatial configuration of the charged species is investigated. It is also shown explicitly that the probability for singlet formation as a result of cross recombination is equal to 1/4, when spin relaxation by magnetic interaction with the medium and by exchange interaction can be neglected. The effect of the preferential recombination on the singlet formation probability is illustrated and recent experimental results on singlet to triplet ratios are discussed. (author)

Damage-induced ectopic recombination in the yeast Saccharomyces cerevisiae.

Science.gov (United States)

Kupiec, M; Steinlauf, R

1997-06-09

Mitotic recombination in the yeast Saccharomyces cerevisiae is induced when cells are irradiated with UV or X-rays, reflecting the efficient repair of damage by recombinational repair mechanisms. We have used multiply marked haploid strains that allow the simultaneous detection of several types of ectopic recombination events. We show that inter-chromosomal ectopic conversion of lys2 heteroalleles and, to a lesser extent, direct repeat recombination (DRR) between non-tandem repeats, are increased by DNA-damaging agents; in contrast, ectopic recombination of the naturally occurring Ty element is not induced. We have tested several hypotheses that could explain the preferential lack of induction of Ty recombination by DNA-damaging agents. We have found that the lack of induction cannot be explained by a cell cycle control or by an effect of the mating-type genes. We also found no role for the flanking long terminal repeats (LTRs) of the Ty in preventing the induction. Ectopic conversion, DRR, and forward mutation of artificial repeats show different kinetics of induction at various positions of the cell cycle, reflecting different mechanisms of recombination. We discuss the mechanistic and evolutionary aspects of these results.

A Glance at Recombination Hotspots in the Domestic Cat.

Directory of Open Access Journals (Sweden)

Hasan Alhaddad

Full Text Available Recombination has essential roles in increasing genetic variability within a population and in ensuring successful meiotic events. The objective of this study is to (i infer the population-scaled recombination rate (ρ, and (ii identify and characterize regions of increased recombination rate for the domestic cat, Felis silvestris catus. SNPs (n = 701 were genotyped in twenty-two East Asian feral cats (random bred. The SNPs covered ten different chromosomal regions (A1, A2, B3, C2, D1, D2, D4, E2, F2, X with an average region size of 850 Kb and an average SNP density of 70 SNPs/region. The Bayesian method in the program inferRho was used to infer regional population recombination rates and hotspots localities. The regions exhibited variable population recombination rates and four decisive recombination hotspots were identified on cat chromosome A2, D1, and E2 regions. As a description of the identified hotspots, no correlation was detected between the GC content and the locality of recombination spots, and the hotspots enclosed L2 LINE elements and MIR and tRNA-Lys SINE elements.

Dielectronic recombination theory

International Nuclear Information System (INIS)

LaGattuta, K.J.

1991-01-01

A theory now in wide use for the calculation of dielectronic recombination cross sections (σ DR ) and rate coefficients (α DR ) was one introduced originally by Feshbach for nuclear physics applications, and then later adapted for atomic scattering problems by Hahn. In the following, we briefly review this theory in a very general form, which allows one to account for the effects of overlapping and interacting resonances, as well as continuum-continuum coupling. An extension of our notation will then also allow for the inclusion of the effects of direct radiative recombination, along with a treatment of the interference between radiative and dielectronic recombination. Other approaches to the calculation of σ DR have been described by Fano and by Seaton. We will not consider those theories here. Calculations of α DR have progressed considerably over the last 25 years, since the early work of Burgess. Advances in the reliability of theoretical predictions have also been promoted recently b a variety of direct laboratory measurements of σ DR . While the measurements of σ DR for δn ≠ 0 excitations have tended to agree very well with calculations, the case of δn = 0 has been much problematic. However, by invoking a mechanism originally proposed by Jacobs, which takes into account the effect of stray electric fields on high Rydberg states (HRS) participating in the DR process, new calculations have improved the agreement between theory and experiment for these cases. Nevertheless, certain discrepancies still remain

Scrambling Eggs: Meiotic Drive and the Evolution of Female Recombination Rates

Science.gov (United States)

Brandvain, Yaniv; Coop, Graham

2012-01-01

Theories to explain the prevalence of sex and recombination have long been a central theme of evolutionary biology. Yet despite decades of attention dedicated to the evolution of sex and recombination, the widespread pattern of sex differences in the recombination rate is not well understood and has received relatively little theoretical attention. Here, we argue that female meiotic drivers—alleles that increase in frequency by exploiting the asymmetric cell division of oogenesis—present a potent selective pressure favoring the modification of the female recombination rate. Because recombination plays a central role in shaping patterns of variation within and among dyads, modifiers of the female recombination rate can function as potent suppressors or enhancers of female meiotic drive. We show that when female recombination modifiers are unlinked to female drivers, recombination modifiers that suppress harmful female drive can spread. By contrast, a recombination modifier tightly linked to a driver can increase in frequency by enhancing female drive. Our results predict that rapidly evolving female recombination rates, particularly around centromeres, should be a common outcome of meiotic drive. We discuss how selection to modify the efficacy of meiotic drive may contribute to commonly observed patterns of sex differences in recombination. PMID:22143919

Recombinant expression systems: the obstacle to helminth vaccines?

Science.gov (United States)

Geldhof, Peter; De Maere, Veerle; Vercruysse, Jozef; Claerebout, Edwin

2007-11-01

The need for alternative ways to control helminth parasites has in recent years led to a boost in vaccination experiments with recombinant antigens. Despite the use of different expression systems, only a few recombinants induced high levels of protection against helminths. This is often attributed to the limitations of the current expression systems. Therefore, the need for new systems that can modify and glycosylate the expressed antigens has been advocated. However, analysis of over 100 published vaccine trials with recombinant helminth antigens indicates that it is often not known whether the native parasite antigen itself can induce protection or, if it does, which epitopes are important. This information is vital for a well-thought-out strategy for recombinant production. So, in addition to testing more expression systems, it should be considered that prior evaluation and characterization of the native antigens might help the development of recombinant vaccines against helminths in the long term.

A study on the hydrogen recombination rates of catalytic recombiners and deliberate ignition

International Nuclear Information System (INIS)

Fineschi, F.; Bazzichi, M.; Carcassi, M.

1994-01-01

A study is being carried out by the Department of Nuclear and Mechanical Constructions (DCMN) at the University of Pisa on catalytic recombiners and on deliberately induced weak deflagration. The recombination rates of different types of catalytic devices were obtained from a thorough analysis of published experimental data. The main parameter that affects the effectiveness of these devices seems to be the molar density of the deficiency reactant rather than its volumetric concentration. The recombination rate of weak deflagrations in vented compartments has been assessed with experimental tests carried out in a small scale glass vessel. Through a computerized system of analysis of video recordings of the deflagrations, the flame surface and the burned gas volume were obtained as functions of time. Although approximations are inevitable, the method adopted to identify the position of the flame during propagation is more reliable than other non-visual methods (thermocouples and ion-probes). It can only easily be applied to vented weak deflagrations, i.e. when the hydrogen concentration is far from stoichiometric conditions and near to flammability limits, because the pressurization has to be limited due to the low mechanical resistance of the glass. The values of flame surface and burned gas volume were used as inputs for a computer code to calculate the recombining rate, the burning velocity and the pressure transient in the experimental test. The code is being validated with a methodology principally based on a comparison of the measurements of pressure with the calculated values. The research gave some very interesting results on a small scale which should in the future be compared with large scale data

Photoionization and electron-ion recombination of Cr I

International Nuclear Information System (INIS)

Nahar, Sultana N.

2009-01-01

Using the unified method, the inverse processes of photoionization and electron-ion recombination are studied in detail for neutral chromium, (CrI+hν↔CrII+e), for the ground and excited states. The unified method based on close-coupling approximation and R-matrix method (i) subsumes both the radiative recombination (RR) and dielectronic recombination (DR) for the total rate and (ii) provides self-consistent sets of photoionization cross sections σ PI and recombination rates α RC . The present results show in total photoionization of the ground and excited states an enhancement in the background at the first excited threshold, 3d 4 4s 5 D state of the core. One prominent phot-excitation-of-core (PEC) resonance due to one dipole allowed transition ( 6 S- 6 P o ) in the core is found in the photoionization cross sections of most of the valence electron excited states. Structures in the total and partial photoionization, for ionization into various excited core states and ground state only, respectively, are demonstrated. Results are presented for the septet and quintet states with n≤10 and l≤9 of Cr I. These states couple to the core ground state 6 S and contribute to the recombination rates. State-specific recombination rates are also presented for these states and their features are illustrated. The total recombination rate shows two DR peaks, one at a relatively low temperature, at 630 K, and the other around 40,000 K. This can explain existence of neutral Cr in interstellar medium. Calculations were carried out in LS coupling using a close-coupling wave function expansion of 40 core states. The results illustrate the features in the radiative processes of Cr I and provide photoionization cross sections and recombination rates with good approximation for this astrophysically important ion.

Workshop on Radio Recombination Lines

CERN Document Server

1980-01-01

Since their first detection 15 years ago, radio recombination lines from several elements have been observed in a wide variety of objects including HII regions, planetary nebulae, molecular clouds, the diffuse interstellar medium, and recently, other galaxies. The observations span almost the entire range from 0.1 to 100 GHz, and employ both single­ djsh and aperture synthesis techniques. The theory of radio recombination lines has also advanced strongly, to the point where it is perhaps one of the best-understood in astro­ physics. In a parallel development, it has become possible over the last decade to study these same highly-excited atoms in the laboratory; this work provides further confirmation of the theoretical framework. However there has been continuing controversy over the astrophysical interpre­ tation of radio recombination line observations, especially regarding the role of stimulated emission. A workshop was held in Ottawa on 24-25 August, 1979, bringing together many of the active scientist...

Determination of recombination in Mycoplasma hominis

DEFF Research Database (Denmark)

Jacobsen, Iben Søgaard; Boesen, Thomas; Mygind, Tina

2002-01-01

disequilibrium and distance between the segregating sites, by the homoplasy ratio (H ratio), and by compatibility matrices. The gap gene showed well-supported evidence for high levels of recombination, whereas recombination was less frequent and not significant within the other genes. The analysis revealed......B-hitL, excinuclease ABC subunit A (uvrA) and glyceraldehyde-3-phosphate dehydrogenase (gap) genes. The level of variability of these M. hominis genes was low compared with the housekeeping genes from Helicobacter pylori and Neisseria meningitidis, but only few M. hominis isolates had identical sequences in all genes...... intergenic and intragenic recombination in M. hominis and this may explain the high intraspecies variability. The results obtained in the present study may be of importance for future population studies of Mycoplasma species....

Radiative and three-body recombination in the Alcator C-Mod divertor

International Nuclear Information System (INIS)

Lumma, D.; Terry, J.L.; Lipschultz, B.

1997-01-01

Significant recombination of the majority ion species has been observed in the divertor region of Alcator C-Mod [I. H. Hutchinson et al., Phys. Plasmas 1, 1511 (1994)] under detached conditions. This determination is made by analysis of the visible spectrum from the divertor, in particular the Balmer series line emission and the observed recombination continuum, including an apparent recombination edge at ∼375 nm. The analysis shows that the electron temperature in the recombining plasma is 0.8 endash 1.5 eV. The measured volume recombination rate is comparable to the rate of ion collection at the divertor plates. The dominant recombination mechanism is three-body recombination into excited states (e+e+D + Right-arrow D 0 +e), although radiative recombination (e+D + Right-arrow D 0 +hν) contributes ∼5% to the total rate. Analysis of the Balmer series line intensities (from n upper =3 through 10) shows that the upper levels of these transitions are populated primarily by recombination. Thus the brightnesses of the Balmer series (and Lyman series) are directly related to the recombination rate. copyright 1997 American Institute of Physics

Recombination Promoted by DNA Viruses: Phage λ to Herpes Simplex Virus

Science.gov (United States)

Weller, Sandra K.; Sawitzke, James A.

2015-01-01

The purpose of this review is to explore recombination strategies in DNA viruses. Homologous recombination is a universal genetic process that plays multiple roles in the biology of all organisms, including viruses. Recombination and DNA replication are interconnected, with recombination being essential for repairing DNA damage and supporting replication of the viral genome. Recombination also creates genetic diversity, and viral recombination mechanisms have important implications for understanding viral origins as well as the dynamic nature of viral-host interactions. Both bacteriophage λ and herpes simplex virus (HSV) display high rates of recombination, both utilizing their own proteins and commandeering cellular proteins to promote recombination reactions. We focus primarily on λ and HSV, as they have proven amenable to both genetic and biochemical analysis and have recently been shown to exhibit some surprising similarities that will guide future studies. PMID:25002096

A New Metazoan Recombination Rate Record and Consistently High Recombination Rates in the Honey Bee Genus Apis Accompanied by Frequent Inversions but Not Translocations

Science.gov (United States)

Kuster, Ryan; Miller, Katelyn; Fouks, Bertrand; Rubio Correa, Sara; Collazo, Juan; Phaincharoen, Mananya; Tingek, Salim; Koeniger, Nikolaus

2016-01-01

Abstract Western honey bees (Apis mellifera) far exceed the commonly observed 1–2 meiotic recombination events per chromosome and exhibit the highest Metazoan recombination rate (20 cM/Mb) described thus far. However, the reasons for this exceptional rate of recombination are not sufficiently understood. In a comparative study, we report on the newly constructed genomic linkage maps of Apis florea and Apis dorsata that represent the two honey bee lineages without recombination rate estimates so far. Each linkage map was generated de novo, based on SNP genotypes of haploid male offspring of a single female. The A. florea map spans 4,782 cM with 1,279 markers in 16 linkage groups. The A. dorsata map is 5,762 cM long and contains 1,189 markers in 16 linkage groups. Respectively, these map sizes result in average recombination rate estimates of 20.8 and 25.1 cM/Mb. Synteny analyses indicate that frequent intra-chromosomal rearrangements but no translocations among chromosomes accompany the high rates of recombination during the independent evolution of the three major honey bee lineages. Our results imply a common cause for the evolution of very high recombination rates in Apis. Our findings also suggest that frequent homologous recombination during meiosis might increase ectopic recombination and rearrangements within but not between chromosomes. It remains to be investigated whether the resulting inversions may have been important in the evolutionary differentiation between honey bee species. PMID:28173114

Analysis of chickens for recombination within the MHC (B-complex)

DEFF Research Database (Denmark)

Skjødt, K; Koch, C; Crone, M

1985-01-01

In an attempt to further map the chicken MHC (the B complex), a systematic search for genetic recombinants within the B complex was performed by serotyping the progeny from F2 crosses of chickens by means of specific anti-class I, anti-class II, and anti-class IV alloantisera. Two recombinant B......-haplotypes (B21r and B15r) were found by analysing 2,656 F2 chickens representing 5,312 informative typings. In either case, the B-G (class IV) allele was recombined with both the B-F and B-L alleles of the opposite haplotype. MLC typings, tests for direct compatibility by GVH reactions, and absorption analyses...... confirmed the original serological typing of the two recombinant B haplotypes. No recombination between B-F (class I) and B-L (class II) loci was found. This very low frequency of recombination within the B complex as compared with recombination frequencies found in mammalian MHC's is discussed...

Meiotic recombination hotspots - a comparative view.

Science.gov (United States)

Choi, Kyuha; Henderson, Ian R

2015-07-01

During meiosis homologous chromosomes pair and undergo reciprocal genetic exchange, termed crossover. Meiotic recombination has a profound effect on patterns of genetic variation and is an important tool during crop breeding. Crossovers initiate from programmed DNA double-stranded breaks that are processed to form single-stranded DNA, which can invade a homologous chromosome. Strand invasion events mature into double Holliday junctions that can be resolved as crossovers. Extensive variation in the frequency of meiotic recombination occurs along chromosomes and is typically focused in narrow hotspots, observed both at the level of DNA breaks and final crossovers. We review methodologies to profile hotspots at different steps of the meiotic recombination pathway that have been used in different eukaryote species. We then discuss what these studies have revealed concerning specification of hotspot locations and activity and the contributions of both genetic and epigenetic factors. Understanding hotspots is important for interpreting patterns of genetic variation in populations and how eukaryotic genomes evolve. In addition, manipulation of hotspots will allow us to accelerate crop breeding, where meiotic recombination distributions can be limiting. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Cell biology of homologous recombination in yeast

DEFF Research Database (Denmark)

Eckert-Boulet, Nadine Valerie; Rothstein, Rodney; Lisby, Michael

2011-01-01

Homologous recombination is an important pathway for error-free repair of DNA lesions, such as single- and double-strand breaks, and for rescue of collapsed replication forks. Here, we describe protocols for live cell imaging of single-lesion recombination events in the yeast Saccharomyces...

Recombination Parameters for Antimonide-Based Semiconductors using RF Photoreflection Techniques

International Nuclear Information System (INIS)

Kumar, R.J.; Borrego, J.M.; Dutta, P.S.; Gutmann, R.J.; Wang, C.A.; Martinelli, R.U.; Nichols, G.

2002-01-01

RF photoreflection measurements and PC-1D simulations have been used to evaluate bulk and surface recombination parameters in antimonide-based materials. PC-1D is used to simulate the photoconductivity response of antimonide-based substrates and doubly-capped epitaxial layers and also to determine how to extract the recombination parameters using experimental results. Excellent agreement has been obtained with a first-order model and test structure simulation when Shockley-Reed-Hall (SRH) recombination is the bulk recombination process. When radiative, Auger and surface recombination are included, the simulation results show good agreement with the model. RF photoreflection measurements and simulations using PC-1D are compatible with a radiative recombination coefficient (B) of approximately 5 x 10 -11 cm 3 /s, Auger coefficient (C) ∼ 1.0 x 10 -28 cm 6 /s and surface recombination velocity (SRV) ∼ 600 cm/s for 0.50-0.55 eV doubly-capped InGaAsSb material with GaSb capping layers using the experimentally determined active layer doping of 2 x 10 17 cm -3 . Photon recycling, neglected in the analysis and simulations presented, will affect the extracted recombination parameters to some extent

Effects of the rad52 gene on recombination in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Prakash, S.; Prakash, L.; Burke, W.; Montelone, B.A.

1980-01-01

Effects of the rad 52 mutation in Saccharomyces cerevisiae on meiotic, γ-ray-induced, uv-induced and spontaneous mitotic recombination were studied. The rad52/rad52 diploids undergo premeiotic DNA synthesis; sporulation occurs but inviable spores are produced. Both intra and intergenic recombination during meiosis were examined in cells transferred from sporulation medium to vegetative medium at different time intervals. No intragenic recombination was observed at the his1-1/his1-315 and trp-5-2/trp5-48 heteroalleles. Gene-centromere recombination also was not observed in rad/52/rad52 diploids. No γ-ray- or uv-induced intragenic mitotic recombination is seen in rad52/rad52 diploids. The rate of spontaneous mitotic recombination is lowered five-fold at the his1-1/his1-315 and leu1-c/leu1-12 heteroalleles. Spontaneous reversion rates of both his1-1 and his1-315 were elevated 10 to 20 fold in rad52/rad52 diploids. The RAD52 gene function is required for spontaneous mitotic recombination, uv- and γ-ray-induced mitotic recombination and mitotic recombination

Phylogenetic and recombination analysis of tomato spotted wilt virus.

Directory of Open Access Journals (Sweden)

Sen Lian

Full Text Available Tomato spotted wilt virus (TSWV severely damages and reduces the yield of many economically important plants worldwide. In this study, we determined the whole-genome sequences of 10 TSWV isolates recently identified from various regions and hosts in Korea. Phylogenetic analysis of these 10 isolates as well as the three previously sequenced isolates indicated that the 13 Korean TSWV isolates could be divided into two groups reflecting either two different origins or divergences of Korean TSWV isolates. In addition, the complete nucleotide sequences for the 13 Korean TSWV isolates along with previously sequenced TSWV RNA segments from Korea and other countries were subjected to phylogenetic and recombination analysis. The phylogenetic analysis indicated that both the RNA L and RNA M segments of most Korean isolates might have originated in Western Europe and North America but that the RNA S segments for all Korean isolates might have originated in China and Japan. Recombination analysis identified a total of 12 recombination events among all isolates and segments and five recombination events among the 13 Korea isolates; among the five recombinants from Korea, three contained the whole RNA L segment, suggesting reassortment rather than recombination. Our analyses provide evidence that both recombination and reassortment have contributed to the molecular diversity of TSWV.

Effect of interface roughness on Auger recombination in semiconductor quantum wells

Science.gov (United States)

Tan, Chee-Keong; Sun, Wei; Wierer, Jonathan J.; Tansu, Nelson

2017-03-01

Auger recombination in a semiconductor is a three-carrier process, wherein the energy from the recombination of an electron and hole pair promotes a third carrier to a higher energy state. In semiconductor quantum wells with increased carrier densities, the Auger recombination becomes an appreciable fraction of the total recombination rate and degrades luminescence efficiency. Gaining insight into the variables that influence Auger recombination in semiconductor quantum wells could lead to further advances in optoelectronic and electronic devices. Here we demonstrate the important role that interface roughness has on Auger recombination within quantum wells. Our computational studies find that as the ratio of interface roughness to quantum well thickness is increased, Auger recombination is significantly enhanced. Specifically, when considering a realistic interface roughness for an InGaN quantum well, the enhancement in Auger recombination rate over a quantum well with perfect heterointerfaces can be approximately four orders of magnitude.

Total and partial recombination cross sections for F6+

International Nuclear Information System (INIS)

Mitnik, D.M.; Pindzola, M.S.; Badnell, N.R.

1999-01-01

Total and partial recombination cross sections for F 6+ are calculated using close-coupling and distorted-wave theory. For total cross sections, close-coupling and distorted-wave results, which include interference between the radiative and dielectronic pathways, are found to be in good agreement with distorted-wave results based on a sum of independent processes. Total cross sections near zero energy are dominated by contributions from low-energy dielectronic recombination resonances. For partial cross sections, the close-coupling and distorted-wave theories predict strong interference for recombination into the final recombined ground state 1s 2 2s 21 S 0 of F 5+ , but only weak interference for recombination into the levels of the 1s 2 2s2p configuration. copyright 1999 The American Physical Society

B chromosomes are associated with redistribution of genetic recombination towards lower recombination chromosomal regions in perennial ryegrass.

Science.gov (United States)

Harper, John; Phillips, Dylan; Thomas, Ann; Gasior, Dagmara; Evans, Caron; Powell, Wayne; King, Julie; King, Ian; Jenkins, Glyn; Armstead, Ian

2018-04-09

Supernumerary 'B' chromosomes are non-essential components of the genome present in a range of plant and animal species-including many grasses. Within diploid and polyploid ryegrass and fescue species, including the forage grass perennial ryegrass (Lolium perenne L.), the presence of B chromosomes has been reported as influencing both chromosome pairing and chiasma frequencies. In this study, the effects of the presence/absence of B chromosomes on genetic recombination has been investigated through generating DArT (Diversity Arrays Technology) marker genetic maps for six perennial ryegrass diploid populations, the pollen parents of which contained either two B or zero B chromosomes. Through genetic and cytological analyses of these progeny and their parents, we have identified that, while overall cytological estimates of chiasma frequencies were significantly lower in pollen mother cells with two B chromosomes as compared with zero B chromosomes, the recombination frequencies within some marker intervals were actually increased, particularly for marker intervals in lower recombination regions of chromosomes, namely pericentromeric regions. Thus, in perennial ryegrass, the presence of two B chromosomes redistributed patterns of meiotic recombination in pollen mother cells in ways which could increase the range of allelic variation available to plant breeders.

Analysis of intermolecular RNA-RNA recombination by rubella virus

International Nuclear Information System (INIS)

Adams, Sandra D.; Tzeng, W.-P.; Chen, M.-H.; Frey, Teryl K.

2003-01-01

To investigate whether rubella virus (RUB) undergoes intermolecular RNA-RNA recombination, cells were cotransfected with pairs of in vitro transcripts from genomic cDNA plasmid vectors engineered to contain nonoverlapping deletions: the replicative transcript maintained the 5'-proximal nonstructural (NS) ORF (which contained the replicase, making it RNA replication competent), had a deletion in the 3'-proximal structural protein (SP) ORF, and maintained the 3' end of the genome, including the putative 3' cis-acting elements (CSE), while the nonreplicative transcript consisted of the 3' half of the genome including the SP-ORF and 3' CSE. Cotransfection yielded plaque-forming virus that synthesized the standard genomic and subgenomic RNAs and thus was generated by RNA-RNA recombination. Using transcripts tagged with a 3'-terminal deletion, it was found that recombinants contained the 3' end derived from the replicative strand, indicating a cis-preference for initiation of negative-strand synthesis. In cotransfections in which the replicative transcript lacked the 3' CSE, recombination occurred, albeit at lower efficiency, indicating that initiation in trans from the NS-ORF can occur. The 3' CSE was sufficient as a nonreplicative transcript, showing that it can serve as a promoter for negative-strand RNA synthesis. While deletion mutagenesis showed that the presence of the junction untranslated region (J-UTR) between the ORFs appeared to be necessary on both transcripts for recombination in this region of the genome, analysis with transcripts tagged with restriction sites showed that the J-UTR was not a hot spot for recombination compared to neighboring regions in both ORFs. Sequence analysis of recombinants revealed that both precise (homologous) and imprecise recombination (aberrant, homologous resulting in duplications) occurred; however, imprecise recombination only involved the J-UTR or the 3' end of the NS-ORF and the J-UTR (maintaining the NS-ORF), indicating

Intrinsic and experimental quasiparticle recombination times in superconducting films

International Nuclear Information System (INIS)

Eisenmenger, W.; Lassmann, K.; Trumpp, H.J.; Krauss, R.

1977-01-01

Experimental quasiparticle recombination lifetime data for superconducting Al, Sn, and Pb films are compared with calculations based on a ray acoustic model taking account of the film thickness dependence of the reabsorption of recombination phonons. Information on the true or intrinsic quasiparticle recombination lifetime obtained from these and other data is discussed. (orig.) [de

Generation of Modified Pestiviruses by Targeted Recombination

DEFF Research Database (Denmark)

Rasmussen, Thomas Bruun; Friis, Martin Barfred; Risager, Peter Christian

involves targeted modification of viral cDNA genomes, cloned within BACs, by Red/ET recombination-mediated mutagenesis in E.coli DH10B cells. Using recombination-mediated mutagenesis for the targeted design, the work can be expedited and focused in principal on any sequence within the viral genome...

Polarity of recombination in transformation of Streptococcus pneumoniae.

Science.gov (United States)

Pasta, F; Sicard, M A

1999-03-16

In transformation of Streptococcus pneumoniae DNA enters the cell as single-strand fragments and integrates into the chromosome by homologous recombination. Deletions and insertions of a few hundred base pairs frequently stop the recombination process of a donor strand. In this work we took advantage of such interruptions of recombination to compare the transformation efficiencies of the segments 5'- and 3'-ward from a deletion. The deletion was created in the center of a fragment of the ami locus, and sites around the deletion were labeled by a frameshift generating a restriction site. Heteroduplexes were constructed containing two restriction sites on one strand and two different ones on the complementary strand. ami+ bacteria were transformed with such heteroduplexes. ami- transformants were isolated and individually underwent amplification of the transformed ami region. We have obtained two kinds of amplification products: short when the deletion was integrated, long when recombination stops at the deletion. Each long fragment was tested by the four restriction enzymes to detect which strand and which side of the deletion had recombined. We found that 80% of the cuts were located 5' to the deletion, showing that, in vivo, the 5' side is strongly favored by recombination. Further results suggest that exchanges occurring from 5' to 3' relative to the donor strand are more efficient than in the opposite direction, thus accounting for the 5' preference.

Recombinant activated factor VII in cardiac surgery: single-center experience.

Science.gov (United States)

Singh, Sarvesh Pal; Chauhan, Sandeep; Choudhury, Minati; Malik, Vishwas; Choudhary, Shiv Kumar

2014-02-01

The widespread off-label use of recombinant activated factor VII for the control of refractory postoperative hemorrhage continues despite a warning from the Food and Drug Administration. Although effective in reducing the need for transfusion of blood and blood products, safety concerns still prevail. To compare the dosing and efficacy of recombinant activated factor VII between pediatric and adult patients, and in the operating room and intensive care unit. The records of 69 patients (33 children and 36 adults) who underwent cardiovascular surgery and received recombinant activated factor VII were reviewed retrospectively. The dose of recombinant activated factor VII, mediastinal drainage, use of blood and blood products, incidence of thrombosis, and 28-day mortality were studied. the efficacy of recombinant activated factor VII was comparable in adults and children, despite the lower dose in adults. Prophylactic use of recombinant activated factor VII decreased the incidence of mediastinal exploration and the duration of intensive care unit stay. A 4.3% incidence of thrombotic complications was observed in this study. The efficacious dose of recombinant activated factor VII is much less in adults compared to children. Prophylactic use of recombinant activated factor VII decreases the dose required, the incidence of mediastinal exploration, and intensive care unit stay, with no survival benefit.

Homologous Recombination as a Replication Fork Escort: Fork-Protection and Recovery

Directory of Open Access Journals (Sweden)

Audrey Costes

2012-12-01

Full Text Available Homologous recombination is a universal mechanism that allows DNA repair and ensures the efficiency of DNA replication. The substrate initiating the process of homologous recombination is a single-stranded DNA that promotes a strand exchange reaction resulting in a genetic exchange that promotes genetic diversity and DNA repair. The molecular mechanisms by which homologous recombination repairs a double-strand break have been extensively studied and are now well characterized. However, the mechanisms by which homologous recombination contribute to DNA replication in eukaryotes remains poorly understood. Studies in bacteria have identified multiple roles for the machinery of homologous recombination at replication forks. Here, we review our understanding of the molecular pathways involving the homologous recombination machinery to support the robustness of DNA replication. In addition to its role in fork-recovery and in rebuilding a functional replication fork apparatus, homologous recombination may also act as a fork-protection mechanism. We discuss that some of the fork-escort functions of homologous recombination might be achieved by loading of the recombination machinery at inactivated forks without a need for a strand exchange step; as well as the consequence of such a model for the stability of eukaryotic genomes.

Low-temperature radiative recombination of electrons with bare nuclei

International Nuclear Information System (INIS)

Omidvar, K.

1993-01-01

Aside from empirical formulas, the radiative-recombination cross section and coefficient are usually given in tabulated forms instead of analytic formulas. Here, we give analytic expressions in the form of expansions for the recombination cross section as a function of the electron energy E for low E, and for the recombination coefficient as a function of the temperature T for low T. The expansion coefficients are combinations of confluent hypergeometric functions, and are tabulated for a large number of the final principal and angular-momentum quantum numbers n and l. It is shown that the recombination cross section for arbitrary nuclear charge number Z is independent of Z, while the recombination coefficient for T/Z 2 much-lt 1.58x10 5 K increases as Z 2 . Excellent agreement is found with the published tabulated values

PRODUCTION OF RECOMBINANT HIGH pI-BARLEY α-GLUCOSIDASE

DEFF Research Database (Denmark)

Næsted, Henrik; Svensson, Birte

plantlet [1]. Recently, expression and characterization of the recombinant full length, fully functional barley high pI α-glucosidase in Pichia pastoris has been achieved. To enable production of recombinant protein in mg amounts, a transformant harbouring a clone encoding the N-terminally hexa histidine...... tagged recombinant form of the enzyme was propagated using a high cell-density fermentation procedure. This system resulted in successful expression under the highly sensitive methanol utilization phase conducting the fermentation process using a BiostatB 5 L reactor. The recombinant high pI α...... glycosylation of the recombinant α-glucosidase. The enzyme activity was highly stable during the 5 day long fermentation. Characterisation of the enzymatic properties confirmed the specific activity actually to be superior to that of the native enzyme purified from malt [2]. The kinetic parameters Km, Vmax...

High-Resolution Patterns of Meiotic Recombination across the Human Major Histocompatibility Complex

Science.gov (United States)

Cullen, Michael; Perfetto, Stephen P.; Klitz, William; Nelson, George; Carrington, Mary

2002-01-01

Definitive characteristics of meiotic recombination events over large (i.e., >1 Mb) segments of the human genome remain obscure, yet they are essential for establishing the haplotypic structure of the genome and for efficient mapping of complex traits. We present a high-resolution map of recombination at the kilobase level across a 3.3-Mb interval encompassing the major histocompatibility complex (MHC). Genotyping of 20,031 single sperm from 12 individuals resulted in the identification and fine mapping of 325 recombinant chromosomes within genomic intervals as small as 7 kb. Several principal characteristics of recombination in this region were observed: (1) rates of recombination can differ significantly between individuals; (2) intense hot spots of recombination occur at least every 0.8 Mb but are not necessarily evenly spaced; (3) distribution in the location of recombination events can differ significantly among individuals; (4) between hot spots, low levels of recombination occur fairly evenly across 100-kb segments, suggesting the presence of warm spots of recombination; and (5) specific sequence motifs associate significantly with recombination distribution. These data provide a plausible model for recombination patterns of the human genome overall. PMID:12297984

Intermediate bands versus levels in non-radiative recombination

International Nuclear Information System (INIS)

Luque, Antonio; Marti, Antonio; Antolin, Elisa; Tablero, Cesar

2006-01-01

There is a practical interest in developing semiconductors with levels situated within their band gap while preventing the non-radiative recombination that these levels promote. In this paper, the physical causes of this non-radiative recombination are analyzed and the increase in the density of the impurities responsible for the mid-gap levels to the point of forming bands is suggested as the means of suppressing the recombination. Simple models supporting this recommendation and helping in its quantification are presented

Correlation between pairing initiation sites, recombination nodules and meiotic recombination in Sordaria macrospora.

Science.gov (United States)

Zickler, D; Moreau, P J; Huynh, A D; Slezec, A M

1992-09-01

The decrease of meiotic exchanges (crossing over and conversion) in two mutants of Sordaria macrospora correlated strongly with a reduction of chiasmata and of both types of "recombination nodules." Serial section reconstruction electron microscopy was used to compare the synapsis pattern of meiotic prophase I in wild type and mutants. First, synapsis occurred but the number of synaptonemal complex initiation sites was reduced in both mutants. Second, this reduction was accompanied by, or resulted in, modifications of the pattern of synapsis. Genetic and synaptonemal complex maps were compared in three regions along one chromosome arm divided into well marked intervals. Reciprocal exchange frequencies and number of recombination nodules correlated in wild type in the three analyzed intervals, but disparity was found between the location of recombination nodules and exchanges in the mutants. Despite the twofold exchange decrease, sections of the genome such as the short arm of chromosome 2 and telomere regions were sheltered from nodule decrease and from pairing modifications. This indicated a certain amount of diversity in the control of these features and suggested that exchange frequency was dependent not only on the amount of effective pairing but also on the localization of the pairing sites, as revealed by the synaptonemal complex progression in the mutants.

Sequence and recombination analyses of the geminivirus replication

Indian Academy of Sciences (India)

Prakash

2006-09-18

Sep 18, 2006 ... Recombination can provide selective advantage in the evolution of viruses .... Program (v 1.08): Recombination Detection Program (RDP). (Martin and Rybicki ..... Sweet potato leaf curl virus - [US:Louisiana:1994]. AF104036.

Recombinant zoster (shingles) vaccine, RZV - what you need to know

Science.gov (United States)

... year in the United States get shingles. Shingles vaccine (recombinant) Recombinant shingles vaccine was approved by FDA in 2017 for the ... life-threatening allergic reaction after a dose of recombinant shingles vaccine, or has a severe allergy to any component ...

Variation in recombination frequency and distribution across eukaryotes: patterns and processes

Science.gov (United States)

Feulner, Philine G. D.; Johnston, Susan E.; Santure, Anna W.; Smadja, Carole M.

2017-01-01

Recombination, the exchange of DNA between maternal and paternal chromosomes during meiosis, is an essential feature of sexual reproduction in nearly all multicellular organisms. While the role of recombination in the evolution of sex has received theoretical and empirical attention, less is known about how recombination rate itself evolves and what influence this has on evolutionary processes within sexually reproducing organisms. Here, we explore the patterns of, and processes governing recombination in eukaryotes. We summarize patterns of variation, integrating current knowledge with an analysis of linkage map data in 353 organisms. We then discuss proximate and ultimate processes governing recombination rate variation and consider how these influence evolutionary processes. Genome-wide recombination rates (cM/Mb) can vary more than tenfold across eukaryotes, and there is large variation in the distribution of recombination events across closely related taxa, populations and individuals. We discuss how variation in rate and distribution relates to genome architecture, genetic and epigenetic mechanisms, sex, environmental perturbations and variable selective pressures. There has been great progress in determining the molecular mechanisms governing recombination, and with the continued development of new modelling and empirical approaches, there is now also great opportunity to further our understanding of how and why recombination rate varies. This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’. PMID:29109219

Lineage specific recombination rates and microevolution in Listeria monocytogenes

Directory of Open Access Journals (Sweden)

Nightingale Kendra K

2008-10-01

Full Text Available Abstract Background The bacterium Listeria monocytogenes is a saprotroph as well as an opportunistic human foodborne pathogen, which has previously been shown to consist of at least two widespread lineages (termed lineages I and II and an uncommon lineage (lineage III. While some L. monocytogenes strains show evidence for considerable diversification by homologous recombination, our understanding of the contribution of recombination to L. monocytogenes evolution is still limited. We therefore used STRUCTURE and ClonalFrame, two programs that model the effect of recombination, to make inferences about the population structure and different aspects of the recombination process in L. monocytogenes. Analyses were performed using sequences for seven loci (including the house-keeping genes gap, prs, purM and ribC, the stress response gene sigB, and the virulence genes actA and inlA for 195 L. monocytogenes isolates. Results Sequence analyses with ClonalFrame and the Sawyer's test showed that recombination is more prevalent in lineage II than lineage I and is most frequent in two house-keeping genes (ribC and purM and the two virulence genes (actA and inlA. The relative occurrence of recombination versus point mutation is about six times higher in lineage II than in lineage I, which causes a higher genetic variability in lineage II. Unlike lineage I, lineage II represents a genetically heterogeneous population with a relatively high proportion (30% average of genetic material imported from external sources. Phylograms, constructed with correcting for recombination, as well as Tajima's D data suggest that both lineages I and II have suffered a population bottleneck. Conclusion Our study shows that evolutionary lineages within a single bacterial species can differ considerably in the relative contributions of recombination to genetic diversification. Accounting for recombination in phylogenetic studies is critical, and new evolutionary models that

Regulation of Homologous Recombination by SUMOylation

DEFF Research Database (Denmark)

Pinela da Silva, Sonia Cristina

factors such as the homologous recombination (HR) machinery. HR constitutes the main DSB repair pathway in Saccharomyces cerevisiae and despite being largely considered an error-free process and essential for genome stability, uncontrolled recombination can lead to loss of heterozygosity, translocations......, deletions, and genome rearrangements that can lead to cell death or cancer in humans. The post-translational modification by SUMO (small ubiquitinlike modifier) has proven to be an important regulator of HR and genome integrity, but the molecular mechanisms responsible for these roles are still unclear....... In this study I present new insights for the role of SUMOylation in regulating HR by dissecting the role of SUMO in the interaction between the central HR-mediator protein Rad52 and its paralogue Rad59 and the outcome of recombination. This data provides evidence for the importance of SUMO in promoting protein...

Study of volume recombination and radiation opacity effects in Alcator C-Mod

International Nuclear Information System (INIS)

Terry, J.L.; Lipschultz, B.; Pigarov, A.Y.; Boswell, C.; Krasheninnikov, S.I.; LaBombard, B.; Pappas, D.A.

1998-01-01

Observations of significant volume recombination within the Alcator C-Mod divertor plasma and in the edge plasma (MARFE) are described. The recombination occurs in regions where T e approx-lt 1 eV and n e approx-gt 1x10 21 m -3 . The determinations of the recombination rates are made by measuring the D 0 Lyman and/or Balmer spectra and by using a collisional radiative model describing the level populations, ionization and recombination of D 0 . In regions of strong recombination the upper levels (n approx-gt 4) populations are close to those determined by Saha-Boltzmann distribution and are independent of the ground state density. Thus the intensities of lines from these levels are related to the recombination rate, and curves determining the number of open-quote recombinations per photon close-quote are calculated. Ly β line emission is shown to be trapped in some cases, meaning that Ly α can be strongly trapped. Since opacity affects the recombination rates, the effects of the trapping of Ly α,β photons on the open-quote recombinations per photon close-quote curves are calculated and considered in the recombination rate determinations. Total recombination rates in the detached divertor plasma and in MARFEs located at the periphery of the main plasma are determined. Recombination can be a significant sink for ions. copyright 1998 American Institute of Physics

Evidence of recombination in intrapatient populations of hepatitis C virus.

Science.gov (United States)

Sentandreu, Vicente; Jiménez-Hernández, Nuria; Torres-Puente, Manuela; Bracho, María Alma; Valero, Ana; Gosalbes, María José; Ortega, Enrique; Moya, Andrés; González-Candelas, Fernando

2008-09-18

Hepatitis C virus (HCV) is a major cause of liver disease worldwide and a potential cause of substantial morbidity and mortality in the future. HCV is characterized by a high level of genetic heterogeneity. Although homologous recombination has been demonstrated in many members of the family Flaviviridae, to which HCV belongs, there are only a few studies reporting recombination on natural populations of HCV, suggesting that these events are rare in vivo. Furthermore, these few studies have focused on recombination between different HCV genotypes/subtypes but there are no reports on the extent of intra-genotype or intra-subtype recombination between viral strains infecting the same patient. Given the important implications of recombination for RNA virus evolution, our aim in this study has been to assess the existence and eventually the frequency of intragenic recombination on HCV. For this, we retrospectively have analyzed two regions of the HCV genome (NS5A and E1-E2) in samples from two different groups: (i) patients infected only with HCV (either treated with interferon plus ribavirin or treatment naïve), and (ii) HCV-HIV co-infected patients (with and without treatment against HIV). The complete data set comprised 17712 sequences from 136 serum samples derived from 111 patients. Recombination analyses were performed using 6 different methods implemented in the program RDP3. Recombination events were considered when detected by at least 3 of the 6 methods used and were identified in 10.7% of the amplified samples, distributed throughout all the groups described and the two genomic regions studied. The resulting recombination events were further verified by detailed phylogenetic analyses. The complete experimental procedure was applied to an artificial mixture of relatively closely viral populations and the ensuing analyses failed to reveal artifactual recombination. From these results we conclude that recombination should be considered as a potentially

Genome-Wide Fine-Scale Recombination Rate Variation in Drosophila melanogaster

Science.gov (United States)

Song, Yun S.

2012-01-01

Estimating fine-scale recombination maps of Drosophila from population genomic data is a challenging problem, in particular because of the high background recombination rate. In this paper, a new computational method is developed to address this challenge. Through an extensive simulation study, it is demonstrated that the method allows more accurate inference, and exhibits greater robustness to the effects of natural selection and noise, compared to a well-used previous method developed for studying fine-scale recombination rate variation in the human genome. As an application, a genome-wide analysis of genetic variation data is performed for two Drosophila melanogaster populations, one from North America (Raleigh, USA) and the other from Africa (Gikongoro, Rwanda). It is shown that fine-scale recombination rate variation is widespread throughout the D. melanogaster genome, across all chromosomes and in both populations. At the fine-scale, a conservative, systematic search for evidence of recombination hotspots suggests the existence of a handful of putative hotspots each with at least a tenfold increase in intensity over the background rate. A wavelet analysis is carried out to compare the estimated recombination maps in the two populations and to quantify the extent to which recombination rates are conserved. In general, similarity is observed at very broad scales, but substantial differences are seen at fine scales. The average recombination rate of the X chromosome appears to be higher than that of the autosomes in both populations, and this pattern is much more pronounced in the African population than the North American population. The correlation between various genomic features—including recombination rates, diversity, divergence, GC content, gene content, and sequence quality—is examined using the wavelet analysis, and it is shown that the most notable difference between D. melanogaster and humans is in the correlation between recombination and

Hadron correlations from recombination and fragmentation

Energy Technology Data Exchange (ETDEWEB)

Fries, Rainer J [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2005-04-01

We review the formalism of quark recombination applied to the hadronization of a quark-gluon plasma. Evidence in favour of the quark recombination model is outlined. Recent work on parton correlations, leading to detectable correlations between hadrons, is discussed. Hot spots from completely quenched jets are a likely source of such correlations which appear to be jet like. It will be discussed how such a picture compares with measurement of associated hadron yields at RHIC.

Feline immunodeficiency virus (FIV) env recombinants are common in natural infections.

Science.gov (United States)

Bęczkowski, Paweł M; Hughes, Joseph; Biek, Roman; Litster, Annette; Willett, Brian J; Hosie, Margaret J

2014-09-17

Recombination is a common feature of retroviral biology and one of the most important factors responsible for generating viral diversity at both the intra-host and the population levels. However, relatively little is known about rates and molecular processes of recombination for retroviruses other than HIV, including important model viruses such as feline immunodeficiency virus (FIV). We investigated recombination in complete FIV env gene sequences (n = 355) isolated from 43 naturally infected cats. We demonstrated that recombination is abundant in natural FIV infection, with over 41% of the cats being infected with viruses containing recombinant env genes. In addition, we identified shared recombination breakpoints; the most significant hotspot occurred between the leader/signal fragment and the remainder of env. Our results have identified the leader/signal fragment of env as an important site for recombination and highlight potential limitations of the current phylogenetic classification of FIV based on partial env sequences. Furthermore, the presence of abundant recombinant FIV in the USA poses a significant challenge for commercial diagnostic tests and should inform the development of the next generation of FIV vaccines.

Charge-carrier transport and recombination in heteroepitaxial CdTe

International Nuclear Information System (INIS)

Kuciauskas, Darius; Farrell, Stuart; Dippo, Pat; Moseley, John; Moutinho, Helio; Li, Jian V.; Allende Motz, A. M.; Kanevce, Ana; Zaunbrecher, Katherine; Gessert, Timothy A.; Levi, Dean H.; Metzger, Wyatt K.; Colegrove, Eric; Sivananthan, S.

2014-01-01

We analyze charge-carrier dynamics using time-resolved spectroscopy and varying epitaxial CdTe thickness in undoped heteroepitaxial CdTe/ZnTe/Si. By employing one-photon and nonlinear two-photon excitation, we assess surface, interface, and bulk recombination. Two-photon excitation with a focused laser beam enables characterization of recombination velocity at the buried epilayer/substrate interface, 17.5 μm from the sample surface. Measurements with a focused two-photon excitation beam also indicate a fast diffusion component, from which we estimate an electron mobility of 650 cm 2 (Vs) −1 and diffusion coefficient D of 17 cm 2  s −1 . We find limiting recombination at the epitaxial film surface (surface recombination velocity S surface  = (2.8 ± 0.3) × 10 5  cm s −1 ) and at the heteroepitaxial interface (interface recombination velocity S interface  = (4.8 ± 0.5) × 10 5  cm s −1 ). The results demonstrate that reducing surface and interface recombination velocity is critical for photovoltaic solar cells and electronic devices that employ epitaxial CdTe.

Regulation of homologous recombination at telomeres in budding yeast

DEFF Research Database (Denmark)

Eckert-Boulet, Nadine; Lisby, Michael

2010-01-01

Homologous recombination is suppressed at normal length telomere sequences. In contrast, telomere recombination is allowed when telomeres erode in the absence of telomerase activity or as a consequence of nucleolytic degradation or incomplete replication. Here, we review the mechanisms that contr...... that contribute to regulating mitotic homologous recombination at telomeres and the role of these mechanisms in signalling short telomeres in the budding yeast Saccharomyces cerevisiae....

Recombining overlapping BACs into a single larger BAC

Directory of Open Access Journals (Sweden)

Huxley Clare

2004-01-01

Full Text Available Abstract Background BAC clones containing entire mammalian genes including all the transcribed region and long range controlling elements are very useful for functional analysis. Sequenced BACs are available for most of the human and mouse genomes and in many cases these contain intact genes. However, large genes often span more than one BAC, and single BACs covering the entire region of interest are not available. Here we describe a system for linking two or more overlapping BACs into a single clone by homologous recombination. Results The method was used to link a 61-kb insert carrying the final 5 exons of the human CFTR gene onto a 160-kb BAC carrying the first 22 exons. Two rounds of homologous recombination were carried out in the EL350 strain of bacteria which can be induced for the Red genes. In the first round, the inserts of the two overlapping BACs were subcloned into modified BAC vectors using homologous recombination. In the second round, the BAC to be added was linearised with the very rare-cutting enzyme I-PpoI and electroporated into recombination efficient EL350 bacteria carrying the other BAC. Recombined BACs were identified by antibiotic selection and PCR screening and 10% of clones contained the correctly recombined 220-kb BAC. Conclusion The system can be used to link the inserts from any overlapping BAC or PAC clones. The original orientation of the inserts is not important and desired regions of the inserts can be selected. The size limit for the fragments recombined may be larger than the 61 kb used here and multiple BACs in a contig could be combined by alternating use of the two pBACLink vectors. This system should be of use to many investigators wishing to carry out functional analysis on large mammalian genes which are not available in single BAC clones.

Mitochondrial Recombination and Introgression during Speciation by Hybridization.

Science.gov (United States)

Leducq, Jean-Baptiste; Henault, Mathieu; Charron, Guillaume; Nielly-Thibault, Lou; Terrat, Yves; Fiumera, Heather L; Shapiro, B Jesse; Landry, Christian R

2017-08-01

Genome recombination is a major source of genotypic diversity and contributes to adaptation and speciation following interspecies hybridization. The contribution of recombination in these processes has been thought to be largely limited to the nuclear genome because organelles are mostly uniparentally inherited in animals and plants, which prevents recombination. Unicellular eukaryotes such as budding yeasts do, however, transmit mitochondria biparentally, suggesting that during hybridization, both parents could provide alleles that contribute to mitochondrial functions such as respiration and metabolism in hybrid populations or hybrid species. We examined the dynamics of mitochondrial genome transmission and evolution during speciation by hybridization in the natural budding yeast Saccharomyces paradoxus. Using population-scale mitochondrial genome sequencing in two endemic North American incipient species SpB and SpC and their hybrid species SpC*, we found that both parental species contributed to the hybrid mitochondrial genome through recombination. We support our findings by showing that mitochondrial recombination between parental types is frequent in experimental crosses that recreate the early step of this speciation event. In these artificial hybrids, we observed that mitochondrial genome recombination enhances phenotypic variation among diploid hybrids, suggesting that it could play a role in the phenotypic differentiation of hybrid species. Like the nuclear genome, the mitochondrial genome can, therefore, also play a role in hybrid speciation. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Trends in recombinant protein use in animal production.

Science.gov (United States)

Gifre, Laia; Arís, Anna; Bach, Àlex; Garcia-Fruitós, Elena

2017-03-04

Recombinant technologies have made possible the production of a broad catalogue of proteins of interest, including those used for animal production. The most widely studied proteins for the animal sector are those with an important role in reproduction, feed efficiency, and health. Nowadays, mammalian cells and fungi are the preferred choice for recombinant production of hormones for reproductive purposes and fibrolytic enzymes to enhance animal performance, respectively. However, the development of low-cost products is a priority, particularly in livestock. The study of cell factories such as yeast and bacteria has notably increased in the last decades to make the new developed reproductive hormones and fibrolytic enzymes a real alternative to the marketed ones. Important efforts have also been invested to developing new recombinant strategies for prevention and therapy, including passive immunization and modulation of the immune system. This offers the possibility to reduce the use of antibiotics by controlling physiological processes and improve the efficacy of preventing infections. Thus, nowadays different recombinant fibrolytic enzymes, hormones, and therapeutic molecules with optimized properties have been successfully produced through cost-effective processes using microbial cell factories. However, despite the important achievements for reducing protein production expenses, alternative strategies to further reduce these costs are still required. In this context, it is necessary to make a giant leap towards the use of novel strategies, such as nanotechnology, that combined with recombinant technology would make recombinant molecules affordable for animal industry.

Constraints from jet calculus on quark recombination

International Nuclear Information System (INIS)

Jones, L.M.; Lassila, K.E.; Willen, D.

1979-01-01

Within the QCD jet calculus formalism, we deduce an equation describing recombination of quarks and antiquarks into mesons within a quark or gluon jet. This equation relates the recombination function R(x 1 ,x 2 ,x) used in current literature to the fragmentation function for producing that same meson out of the parton initiating the jet. We submit currently used recombination functions to our consistency test, taking as input mainly the u-quark fragmentation data into π + mesons, but also s-quark fragmentation into K - mesons. The constraint is well satisfied at large Q 2 for large moments. Our results depend on one parameter, Q 0 2 , the constraint equation being satisfied for small values of this parameter

Experimental study of para- and ortho-H3+ recombination

International Nuclear Information System (INIS)

Plasil, R; Varju, J; Hejduk, M; Dohnal, P; KotrIk, T; Glosik, J

2011-01-01

Recombination of H 3 + with electrons is a key process for many plasmatic environments. Recent experiments on storage ring devices used ion sources producing H 3 + with enhanced populations of H 3 + ions in the para nuclear spin configuration to shed light on the theoretically predicted faster recombination of para states. Although increased recombination rates were observed, no in situ characterization of recombining ions was performed. We present a state selective recombination study of para- and ortho-H 3 + ions with electrons at 77 K in afterglow plasma in a He/Ar/H 2 gas-mixture. Both spin configurations of H 3 + have been observed in situ with a near infrared cavity ring down spectrometer (NIR-CRDS) using the two lowest energy levels of H 3 + . Using hydrogen with an enhanced population of H 2 molecules in para states allowed us to influence the [para-H 3 + ]/[ortho-H 3 + ] ratio in the discharge and in the afterglow. We observed an increase in the measured effective recombination rate coefficients with the increase of the fraction of para-H 3 + . Measurements with different fractions of para-H 3 + at otherwise identical conditions allowed us to determine the binary recombination rate coefficients for pure para-H 3 + p α bin (77 K) = (2.0±0.4)x10 -7 cm 3 s -1 and pure ortho-H 3 + o α bin (77 K) = (4±3)x10 -8 cm 3 s -1 .

Experimental study of para- and ortho-H3+ recombination

Science.gov (United States)

Plašil, R.; Varju, J.; Hejduk, M.; Dohnal, P.; Kotrík, T.; Glosík, J.

2011-07-01

Recombination of H3+ with electrons is a key process for many plasmatic environments. Recent experiments on storage ring devices used ion sources producing H3+ with enhanced populations of H3+ ions in the para nuclear spin configuration to shed light on the theoretically predicted faster recombination of para states. Although increased recombination rates were observed, no in situ characterization of recombining ions was performed. We present a state selective recombination study of para- and ortho-H3+ ions with electrons at 77 K in afterglow plasma in a He/Ar/H2 gas-mixture. Both spin configurations of H3+ have been observed in situ with a near infrared cavity ring down spectrometer (NIR-CRDS) using the two lowest energy levels of H3+. Using hydrogen with an enhanced population of H2 molecules in para states allowed us to influence the [para-H3+]/[ortho-H3+] ratio in the discharge and in the afterglow. We observed an increase in the measured effective recombination rate coefficients with the increase of the fraction of para-H3+. Measurements with different fractions of para-H3+ at otherwise identical conditions allowed us to determine the binary recombination rate coefficients for pure para-H3+ pαbin(77 K) = (2.0±0.4)×10-7 cm3s-1 and pure ortho-H3+ oαbin(77 K) = (4±3)×10-8 cm3s-1.

Characterization of recombination features and the genetic basis in multiple cattle breeds.

Science.gov (United States)

Shen, Botong; Jiang, Jicai; Seroussi, Eyal; Liu, George E; Ma, Li

2018-04-27

Crossover generated by meiotic recombination is a fundamental event that facilitates meiosis and sexual reproduction. Comparative studies have shown wide variation in recombination rate among species, but the characterization of recombination features between cattle breeds has not yet been performed. Cattle populations in North America count millions, and the dairy industry has genotyped millions of individuals with pedigree information that provide a unique opportunity to study breed-level variations in recombination. Based on large pedigrees of Jersey, Ayrshire and Brown Swiss cattle with genotype data, we identified over 3.4 million maternal and paternal crossover events from 161,309 three-generation families. We constructed six breed- and sex-specific genome-wide recombination maps using 58,982 autosomal SNPs for two sexes in the three dairy cattle breeds. A comparative analysis of the six recombination maps revealed similar global recombination patterns between cattle breeds but with significant differences between sexes. We confirmed that male recombination map is 10% longer than the female map in all three cattle breeds, consistent with previously reported results in Holstein cattle. When comparing recombination hotspot regions between cattle breeds, we found that 30% and 10% of the hotspots were shared between breeds in males and females, respectively, with each breed exhibiting some breed-specific hotspots. Finally, our multiple-breed GWAS found that SNPs in eight loci affected recombination rate and that the PRDM9 gene associated with hotspot usage in multiple cattle breeds, indicating a shared genetic basis for recombination across dairy cattle breeds. Collectively, our results generated breed- and sex-specific recombination maps for multiple cattle breeds, provided a comprehensive characterization and comparison of recombination patterns between breeds, and expanded our understanding of the breed-level variations in recombination features within an

Linkage disequilibrium in HLA cannot be explained by selective recombination.

Science.gov (United States)

Termijtelen, A; D'Amaro, J; van Rood, J J; Schreuder, G M

1995-11-01

Some combinations of HLA-A, -B and -DR antigens occur more frequently than would be expected from their gene frequencies in the population. This phenomenon, referred to as Linkage Disequilibrium (LD) has been the origin of many speculations. One hypothesis to explain LD is that some haplotypes are protected from recombination. A second hypothesis is that these HLA antigens preferentially recombine after cross-over to create an LD haplotype. We tested these 2 hypotheses: from a pool of over 10,000 families typed in our department, we analyzed 126 families in which HLA-A:B or B:DR recombinant offspring was documented. To overcome a possible bias in our material, we used the non-recombined haplotypes from the same 126 families as a control group. Our results show that the number of cross-overs through LD haplotypes is not significantly lower then would be expected if recombination occurred randomly. Also the number of LD haplotypes created upon recombination was not significantly increased.

Branching innovation, recombinant innovation, and endogenous technological transitions

NARCIS (Netherlands)

Frenken, K.; Izquierdo, L.; Zeppini, P.

2012-01-01

We propose a model of technological transitions based on two different types of innovations. Branching innovations refer to technological improvements along a particular path, while recombinant innovations represent fusions of multiple paths. Recombinant innovations create "short-cuts" which reduce

Determination of the trap-assisted recombination strength in polymer light emitting diodes

NARCIS (Netherlands)

Kuik, Martijn; Nicolai, Herman T.; Lenes, Martijn; Wetzelaer, Gert-Jan A. H.; Lu, Mingtao; Blom, Paul W. M.

2011-01-01

The recombination processes in poly(p-phenylene vinylene) based polymer light-emitting diodes (PLEDs) are investigated. Photogenerated current measurements on PLED device structures reveal that next to the known Langevin recombination also trap-assisted recombination is an important recombination

Determination of the trap-assisted recombination strength in polymer light emitting diodes

NARCIS (Netherlands)

Kuik, M.; Nicolai, H.T.; Lenes, M.; Wetzelaer, G.-J.A.H.; Lu, M.; Blom, P.W.M.

2011-01-01

The recombination processes in poly(p -phenylene vinylene) based polymer light-emitting diodes (PLEDs) are investigated. Photogenerated current measurements on PLED device structures reveal that next to the known Langevin recombination also trap-assisted recombination is an important recombination

Recombination of a fast expanding plasma

International Nuclear Information System (INIS)

Salvat, M.

1979-05-01

The goal of the following calculations is to determine numerically the recombination of dense plasmas (for instance of laser-produced plasmas). The recombination is computed for plasmas with initial densities of 10 24 27 [m -3 ] and with initial temperatures >= 50 eV. The ionization of the plasma remains essentially constant during the early phase of expansion. The time for which the ionization is 'frozen-in' grows with decreasing initial density and with increasing initial temperature. (orig.) [de

Co-factor activated recombinant adenovirus proteinases

Science.gov (United States)

Anderson, Carl W.; Mangel, Walter F.

1996-08-06

This application describes methods and expression constructs for producing activatable recombinant adenovirus proteinases. Purified activatable recombinant adenovirus proteinases and methods of purification are described. Activated adenovirus proteinases and methods for obtaining activated adenovirus proteinases are further included. Isolated peptide cofactors of adenovirus proteinase activity, methods of purifying and identifying said peptide cofactors are also described. Antibodies immunoreactive with adenovirus proteinases, immunospecific antibodies, and methods for preparing them are also described. Other related methods and materials are also described.

Mitochondrial recombination increases with age in Podospora anserina

NARCIS (Netherlands)

van Diepeningen, Anne D; Goedbloed, Daniël J; Slakhorst, S Marijke; Koopmanschap, A Bertha; Maas, Marc F P M; Hoekstra, Rolf F; Debets, Alfons J M

With uniparental inheritance of mitochondria, there seems little reason for homologous recombination in mitochondria, but the machinery for mitochondrial recombination is quite well-conserved in many eukaryote species. In fungi and yeasts heteroplasmons may be formed when strains fuse and transfer

The Λ0 polarization and the recombination mechanism

International Nuclear Information System (INIS)

Herrera, G.; Montano, L.M.

1997-01-01

We use the recombination and the Thomas Precession Model to obtain a prediction for the Λ 0 polarization in the p+p → Λ 0 + X reaction. We study the effect of the recombination function on the Λ 0 polarization. (author)

A simple negative selection method to identify adenovirus recombinants using colony PCR

Directory of Open Access Journals (Sweden)

Yongliang Zhao

2014-01-01

Conclusions: The negative selection method to identify AdEasy adenovirus recombinants by colony PCR can identify the recombined colony within a short time-period, and maximally avoid damage to the recombinant plasmid by limiting recombination time, resulting in improved adenovirus packaging.

The potential of shifting recombination hotspots to increase genetic gain in livestock breeding.

Science.gov (United States)

Gonen, Serap; Battagin, Mara; Johnston, Susan E; Gorjanc, Gregor; Hickey, John M

2017-07-04

This study uses simulation to explore and quantify the potential effect of shifting recombination hotspots on genetic gain in livestock breeding programs. We simulated three scenarios that differed in the locations of quantitative trait nucleotides (QTN) and recombination hotspots in the genome. In scenario 1, QTN were randomly distributed along the chromosomes and recombination was restricted to occur within specific genomic regions (i.e. recombination hotspots). In the other two scenarios, both QTN and recombination hotspots were located in specific regions, but differed in whether the QTN occurred outside of (scenario 2) or inside (scenario 3) recombination hotspots. We split each chromosome into 250, 500 or 1000 regions per chromosome of which 10% were recombination hotspots and/or contained QTN. The breeding program was run for 21 generations of selection, after which recombination hotspot regions were kept the same or were shifted to adjacent regions for a further 80 generations of selection. We evaluated the effect of shifting recombination hotspots on genetic gain, genetic variance and genic variance. Our results show that shifting recombination hotspots reduced the decline of genetic and genic variance by releasing standing allelic variation in the form of new allele combinations. This in turn resulted in larger increases in genetic gain. However, the benefit of shifting recombination hotspots for increased genetic gain was only observed when QTN were initially outside recombination hotspots. If QTN were initially inside recombination hotspots then shifting them decreased genetic gain. Shifting recombination hotspots to regions of the genome where recombination had not occurred for 21 generations of selection (i.e. recombination deserts) released more of the standing allelic variation available in each generation and thus increased genetic gain. However, whether and how much increase in genetic gain was achieved by shifting recombination hotspots depended

Polyploidization increases meiotic recombination frequency in Arabidopsis

Directory of Open Access Journals (Sweden)

Rehmsmeier Marc

2011-04-01

Full Text Available Abstract Background Polyploidization is the multiplication of the whole chromosome complement and has occurred frequently in vascular plants. Maintenance of stable polyploid state over generations requires special mechanisms to control pairing and distribution of more than two homologous chromosomes during meiosis. Since a minimal number of crossover events is essential for correct chromosome segregation, we investigated whether polyploidy has an influence on the frequency of meiotic recombination. Results Using two genetically linked transgenes providing seed-specific fluorescence, we compared a high number of progeny from diploid and tetraploid Arabidopsis plants. We show that rates of meiotic recombination in reciprocal crosses of genetically identical diploid and autotetraploid Arabidopsis plants were significantly higher in tetraploids compared to diploids. Although male and female gametogenesis differ substantially in meiotic recombination frequency, both rates were equally increased in tetraploids. To investigate whether multivalent formation in autotetraploids was responsible for the increased recombination rates, we also performed corresponding experiments with allotetraploid plants showing strict bivalent pairing. We found similarly increased rates in auto- and allotetraploids, suggesting that the ploidy effect is independent of chromosome pairing configurations. Conclusions The evolutionary success of polyploid plants in nature and under domestication has been attributed to buffering of mutations and sub- and neo-functionalization of duplicated genes. Should the data described here be representative for polyploid plants, enhanced meiotic recombination, and the resulting rapid creation of genetic diversity, could have also contributed to their prevalence.

Tiamulin activity against fastidious and nonfastidious veterinary and human bacterial isolates: initial development of in vitro susceptibility test methods.

Science.gov (United States)

Jones, Ronald N; Pfaller, Michael A; Rhomberg, Paul R; Walter, Donald H

2002-02-01

Tiamulin is a pleuromutilin derivative used in veterinary practice for the control and specific therapy of infections in swine. This report summarizes studies to establish standardized susceptibility testing methods, interpretive criteria, and reagent details for use in veterinary methods recently developed by the National Committee for Clinical Laboratory Standards (NCCLS) (standards M31-A and M37-A, NCCLS, Wayne, Pa., 1999). A total of 636 fastidious and nonfastidious animal and human pathogens were processed by using media and procedures described by the NCCLS. Tiamulin disk diffusion tests used a 30-microg disk concentration, and the proposed MIC breakpoints corresponding to levels achievable in animal target tissues (lung) were or =32 microg/ml for resistance. Correlate zone diameters for specific nonfastidious species were as follows: for Pasteurella multocida and staphylococci tested on Mueller-Hinton agar, susceptibility at > or =19 mm and resistance at or =16 mm and resistance at or =9 mm) was suggested for veterinary fastidious medium broth and enriched chocolate Mueller-Hinton agar. Absolute categorical agreement between NCCLS dilution and disk diffusion test results with these criteria ranged from 90.5 to 96.2%. Tiamulin susceptibility testing methods appear to be accurate in their categorical classification for indicated species, and their availability will allow immediate testing of animal isolates to guide therapy via appropriate levels of dosing and to monitor the development of resistance for agents in this unique class.

Survey of susceptibility to marbofloxacin in bacteria isolated from diseased pigs in Europe.

Science.gov (United States)

El Garch, F; Kroemer, S; Galland, D; Morrissey, I; Woehrle, F

2017-06-17

A monitoring programme of marbofloxacin susceptibility of bacteria from Europe causing respiratory tract infection and meningitis in pigs has been active since 1994 and 2002, respectively. Monitoring digestive, metritis and urinary tract infection (UTI) in pigs has been active since 2005 and susceptibility results until 2013 are presented. Minimum inhibitory concentration (MIC) was determined by broth microdilution. For MIC interpretation, Vétoquinol-evaluated breakpoints were applied. For digestive pathogens, Escherichia coli and Salmonella species (1717 and 300 isolates, respectively) exhibited 7.5 per cent resistance in E coli and no resistance in Salmonella species. Similarly, E coli from metritis (369 isolates) had 7.0 per cent resistance to marbofloxacin. However, E coli from UTI (633 isolates) had higher resistance (10.4 per cent). For Streptococcus suis causing meningitis (585 isolates), marbofloxacin susceptibility was very high with only 0.5 per cent resistance and 0.4 per cent resistance was observed with S suis causing respiratory disease (729 isolates). Other respiratory pathogens were also highly susceptible to marbofloxacin with no resistance in Actinobacillus pleuropneumoniae (647 isolates) or Bordetella bronchiseptica (504 isolates), 0.1 per cent resistance in Pasteurella multocida (1373 isolates) and 1.4 per cent resistance in Haemophilus parasuis (145 isolates). There was no apparent change in marbofloxacin MIC over time for any bacterial pathogen based on MIC 50/90 These data confirm previously published MIC results from porcine and other animal infections. British Veterinary Association.

Isolation and polymerase chain reaction-based identification of Riemerella anatipestifer from ducks in Kerala, India

Directory of Open Access Journals (Sweden)

Manju Soman

2014-10-01

Full Text Available Aim: The aim was to isolate and characterize Riemerella anatipestifer organisms from disease outbreaks in ducks in Kerala. Materials and Methods: Ducklings, suspected of Riemerella infection, were sacrificed and subjected to post-mortem examination. Heart blood smears and impression smears from liver and spleen were examined for the presence of pathogenic organisms. Heart blood, lung, liver, and spleen collected aseptically from the birds were subjected to isolation trials in brain heart infusion agar and 10% bovine blood agar. The isolates were characterized based on morphology, cultural characteristics and biochemical tests, and their identity were confirmed by polymerase chain reaction (PCR and the PCR amplified DNA was sequenced. The antibiotic sensitivity testing of the isolates were carried out using six antibiotics viz ciprofloxacin, chloramphenicol, enrofloxacin, amoxycillin, cotrimoxazole, and gentamicin. Results: Colonies suggestive of Riemerella organisms could be isolated on blood agar. Biochemical characterization and PCR confirmed the identity of isolates as R. anatipestifer. The nucleotide sequence of the PCR product showed 99% homology to the R. anatipestifer sequences in the NCBI. The antibiogram revealed that the organisms were sensitive to ciprofloxacin, enrofloxacin, and gentamicin. Conclusion: The present study suggests that the PCR assay can facilitate fast and proper identification of R. anatipestifer infection in ducks. The assay can also differentiate between R. anatipestifer and Pasteurella multocida and can replace the traditional methods of differentiation which are cumbersome and time-consuming.

Pharmacokinetic/pharmacodynamic evaluation of marbofloxacin as a single injection for Pasteurellaceae respiratory infections in cattle using population pharmacokinetics and Monte Carlo simulations.

Science.gov (United States)

Paulin, A; Schneider, M; Dron, F; Woehrle, F

2018-02-01

Population pharmacokinetic of marbofloxacin was investigated with 52 plasma concentration-time profiles obtained after intramuscular administration of Forcyl® in cattle. Animal's status, pre-ruminant, ruminant, or dairy cow, was retained as a relevant covariate for clearance. Monte Carlo simulations were performed using a stratification by status, and 1000 virtual disposition curves were generated in each bovine subpopulation for the recommended dosage regimen of 10 mg/kg as a single injection. The probability of target attainment (PTA) of pharmacokinetic/pharmacodynamic (PK/PD) ratios associated with clinical efficacy and prevention of resistance was determined in each simulated subpopulation. The cumulative fraction of response (CFR) of animals achieving a PK/PD ratio predictive of positive clinical outcome was then calculated for the simulated dosage regimen, taking into account the minimum inhibitory concentration (MIC) distribution of Pasteurella multocida, Mannheimia haemolytica, and Histophilus somni. When considering a ratio of AUC 0-24 hr /MIC (area under the curve/minimum inhibitory concentration) greater than 125 hr, CFRs ranging from 85% to 100% against the three Pasteurellaceae in each bovine subpopulation were achieved. The PTA of the PK/PD threshold reflecting the prevention of resistances was greater than 90% up to MPC (mutant prevention concentration) values of 1 μg/ml in pre-ruminants and ruminants and 0.5 μg/ml in dairy cows. © 2017 The Authors. Journal of Veterinary Pharmacology and Therapeutics Published by John Wiley & Sons Ltd.

A bibliography of references to avian cholera

Science.gov (United States)

Wilson, Sonoma S.

1979-01-01

Mrs. Wilson has made a genuine effort to include in this bibliography every significant reference to avian cholera since Louis Pasteur's articles appeared in 1880, although she recognizes the likelihood that a few have been overlooked. New listings have been added throughout 1978, but comprehensive coverage of the literature cannot be claimed beyond June of that year.Textbook accounts, because they are generally summaries of work published elsewhere, are excluded. Papers dealing primarily with the biology of Pasteurella multocida, as opposed to the disease it induces in birds, are also excluded, unless they report information of diagnostic usefulness. Short abstracts are not included unless the journals in which they are published are more widely available than those in which the complete articles appear or they are English summaries of foreign language articles.In compiling this bibliography, Mrs. Wilson has made extensive use of Biological Abstracts, the Pesticide Documentation Bulletin, and printouts generated by Bibliographic Retrieval Services, Inc. The "Literature Cited" sections of textbooks and journal articles pertinent to the subject were sources of many additional references. Regardless of the origin of the citation, its accuracy was confirmed by comparison with the original publication, except in those few instances (marked with an asterisk) when the journal was not on the shelves of the libraries accessible to us.The author will be grateful to users of the bibliography who point out errors or omissions.Wayne I. JensenMicrobiologist In Charge

Disclosing respiratory co-infections: a broad-range panel assay for avian respiratory pathogens on a nanofluidic PCR platform.

Science.gov (United States)

Croville, Guillaume; Foret, Charlotte; Heuillard, Pauline; Senet, Alexis; Delpont, Mattias; Mouahid, Mohammed; Ducatez, Mariette F; Kichou, Faouzi; Guerin, Jean-Luc

2018-06-01

Respiratory syndromes (RS) are among the most significant pathological conditions in edible birds and are caused by complex coactions of pathogens and environmental factors. In poultry, low pathogenic avian influenza A viruses, metapneumoviruses, infectious bronchitis virus, infectious laryngotracheitis virus, Mycoplasma spp. Escherichia coli and/or Ornithobacterium rhinotracheale in turkeys are considered as key co-infectious agents of RS. Aspergillus sp., Pasteurella multocida, Avibacterium paragallinarum or Chlamydia psittaci may also be involved in respiratory outbreaks. An innovative quantitative PCR method, based on a nanofluidic technology, has the ability to screen up to 96 samples with 96 pathogen-specific PCR primers, at the same time, in one run of real-time quantitative PCR. This platform was used for the screening of avian respiratory pathogens: 15 respiratory agents, including viruses, bacteria and fungi potentially associated with respiratory infections of poultry, were targeted. Primers were designed and validated for SYBR green real-time quantitative PCR and subsequently validated on the Biomark high throughput PCR nanofluidic platform (Fluidigm©, San Francisco, CA, USA). As a clinical assessment, tracheal swabs were sampled from turkeys showing RS and submitted to this panel assay. Beside systematic detection of E. coli, avian metapneumovirus, Mycoplasma gallisepticum and Mycoplasma synoviae were frequently detected, with distinctive co-infection patterns between French and Moroccan flocks. This proof-of-concept study illustrates the potential of such panel assays for unveiling respiratory co-infection profiles in poultry.

A bighorn sheep die-off in southern Colorado involving a Pasteurellaceae strain that may have originated from syntopic cattle.

Science.gov (United States)

Wolfe, Lisa L; Diamond, Brandon; Spraker, Terry R; Sirochman, Michael A; Walsh, Daniel P; Machin, Chandra M; Bade, Donald J; Miller, Michael W

2010-10-01

We investigated a pasteurellosis epizootic in free-ranging bighorn sheep (Ovis canadensis) wherein a Pasteurellaceae strain carried by syntopic cattle (Bos taurus) under severe winter conditions appeared to contribute to pneumonia in affected bighorns. Twenty-one moribund or dead bighorn sheep were found on the "Fossil Ridge" herd's winter range, Colorado, USA, between 13 December 2007 and 29 February 2008. Eight carcasses examined showed gross or microscopic evidence of acute to subacute fibrinous bronchopneumonia. All eight carcasses yielded at least one β-hemolytic Mannheimia haemolytica biogroup 1(±(G)) strain, and seven also yielded a β-hemolytic Bibersteinia trehalosi biogroup 4 (CDS) strain; evidence of Pasteurella multocida, Mycoplasma ovipneumoniae, and parainfluenza 3 and bovine respiratory syncytial viruses was also detected. Isolates of β-hemolytic Manneimia haemolytica biogroup 1(G) from a bighorn carcass and a syntopic cow showed 99.5% similarity in genetic fingerprints; B. trehalosi biogroup 4(CDS) isolates were ≥94.9% similar to an isolate from a nearby bighorn herd. Field and laboratory observations suggested that pneumonia in affected bighorns may have been caused by a combination of pathogens including two pathogenic Pasteurellaceae strains--one likely of cattle origin and one likely of bighorn origin--with infections in some cases perhaps exacerbated by other respiratory pathogens and severe weather conditions. Our and others' findings suggest that intimate interactions between wild sheep and cattle should be discouraged as part of a comprehensive approach to health management and conservation of North American wild sheep species.

Fusobacterium necrophorum in North American Bighorn Sheep ( Ovis canadensis ) Pneumonia.

Science.gov (United States)

Shanthalingam, Sudarvili; Narayanan, Sanjeevkumar; Batra, Sai Arun; Jegarubee, Bavananthasivam; Srikumaran, Subramaniam

2016-07-01

Fusobacterium necrophorum has been detected in pneumonic bighorn sheep (BHS; Ovis canadensis ) lungs, in addition to the aerobic respiratory pathogens Mannheimia haemolytica , Bibersteinia trehalosi , Pasteurella multocida , and Mycoplasma ovipneumoniae . Similar to M. haemolytica , F. necrophorum produces a leukotoxin. Leukotoxin-induced lysis and degranulation of polymorphonuclear leukocytes (PMNs) and macrophages are responsible for acute inflammation and lung tissue damage characteristic of M. haemolytica -caused pneumonia. As one approach in elucidating the role of F. necrophorum in BHS pneumonia, we determined the frequency of the presence of F. necrophorum in archived pneumonic BHS lung tissues, and susceptibility of BHS leukocytes to F. necrophorum leukotoxin. A species-specific PCR assay detected F. necrophorum in 37% of pneumonic BHS lung tissues (total tested n=70). Sequences of PCR amplicons were similar to the less virulent F. necrophorum subsp. funduliforme. Fusobacterium necrophorum leukotoxin exhibited cytotoxicity to BHS PMNs and peripheral blood mononuclear cells. As with the M. haemolytica leukotoxin, F. necrophorum leukotoxin was more toxic to BHS PMNs than domestic sheep PMNs. It is likely that F. necrophorum enters the lungs after M. haemolytica and other aerobic respiratory pathogens enter the lungs and initiate tissue damage, thereby creating a microenvironment that is conducive for anaerobic bacterial growth. In summary, Fusobacterium leukotoxin is highly toxic for BHS leukocytes; however, based on the PCR findings, it is unlikely to play a direct role in the development of BHS pneumonia.

Evaluation of Phenolic Compounds and Antioxidant and Antimicrobial Activities of Some Common Herbs

Directory of Open Access Journals (Sweden)

Muhammad Abdul Qadir

2017-01-01

Full Text Available The study was designed to evaluate the phenolic, flavonoid contents and antioxidant and antimicrobial activities of onion (Allium cepa, garlic (Allium sativum, mint (Mentha spicata, thyme (Thymus vulgaris, oak (Quercus, aloe vera (Aloe barbadensis Miller, and ginger (Zingiber officinale. All extracts showed a wide range of total phenolic contents, that is, 4.96 to 98.37 mg/100 g gallic acid equivalents, and total flavonoid contents, that is, 0.41 to 17.64 mg/100 g catechin equivalents. Antioxidant activity (AA was determined by measuring reducing power, inhibition of peroxidation using linoleic acid system, and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH scavenging activity. Different extracts inhibited oxidation of linoleic acid by 16.6–84.2% while DPPH radical scavenging activity (IC50 values ranged from 17.8% to 79.1 μg/mL. Reducing power at 10 mg/mL extract concentration ranged from 0.11 to 0.84 nm. Furthermore the extracts of these medicinal herbs in 80% methanol, 80% ethanol, 80% acetone, and 100% water were screened for antimicrobial activity by disc diffusion method against selected bacterial strains, Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Pasteurella multocida, and fungal strains, Aspergillus niger, Aspergillus flavus, Rhizopus solani, and Alternaria alternata. The extracts show better antimicrobial activity against bacterial strains as compared to fungal strains. Results of various assays were analyzed statistically by applying appropriate statistical methods.

Report of recombinant norovirus GII.g/GII.12 in Beijing, China.

Science.gov (United States)

Sang, Shaowei; Zhao, Zhongtang; Suo, Jijiang; Xing, Yubin; Jia, Ning; Gao, Yan; Xie, Lijun; Du, Mingmei; Liu, Bowei; Ren, Shiwang; Liu, Yunxi

2014-01-01

Norovirus (NoV) has been recognized as the most important cause of nonbacterial acute gastroenteritis affecting all age group people in the world. Genetic recombination is a common occurance in RNA viruses and many recombinant NoV strains have been described since it was first reported in 1997. However, the knowledge of recombinant NoV in China is extremely limited. A total of 685 stool specimens were tested for NoV infection from the acute gastroenteritis patients who visited one general hospital in Beijing from April 2009 to November 2011. The virus recombination was identified by constructing phylogenetic trees of two genes, further SimPlot and the maximum chi-square analysis. The overall positive rate was 9.6% (66/685). GII.4 New Orleans 2009 and GII.4 2006b variants were the dominant genotype. Four GII.g/GII.12 and one GII.12/GII.3 recombinant strains were confirmed, and all derived from adult outpatients. The predictive recombination point occurred at the open reading frame (ORF)1/ORF2 overlap. The GII.g ORF1/GII.12ORF2 recombinant has been reported in several countries and it was the first report of this recombinant in China.

Recombinational Cloning Using Gateway and In-Fusion Cloning Schemes

Science.gov (United States)

Throop, Andrea L.; LaBaer, Joshua

2015-01-01

The comprehensive study of protein structure and function, or proteomics, depends on the obtainability of full-length cDNAs in species-specific expression vectors and subsequent functional analysis of the expressed protein. Recombinational cloning is a universal cloning technique based on site-specific recombination that is independent of the insert DNA sequence of interest, which differentiates this method from the classical restriction enzyme-based cloning methods. Recombinational cloning enables rapid and efficient parallel transfer of DNA inserts into multiple expression systems. This unit summarizes strategies for generating expression-ready clones using the most popular recombinational cloning technologies, including the commercially available Gateway® (Life Technologies) and In-Fusion® (Clontech) cloning technologies. PMID:25827088

Productive Homologous and Non-homologous Recombination of Hepatitis C Virus in Cell Culture

Science.gov (United States)

Li, Yi-Ping; Mikkelsen, Lotte S.; Gottwein, Judith M.; Bukh, Jens

2013-01-01

Genetic recombination is an important mechanism for increasing diversity of RNA viruses, and constitutes a viral escape mechanism to host immune responses and to treatment with antiviral compounds. Although rare, epidemiologically important hepatitis C virus (HCV) recombinants have been reported. In addition, recombination is an important regulatory mechanism of cytopathogenicity for the related pestiviruses. Here we describe recombination of HCV RNA in cell culture leading to production of infectious virus. Initially, hepatoma cells were co-transfected with a replicating JFH1ΔE1E2 genome (genotype 2a) lacking functional envelope genes and strain J6 (2a), which has functional envelope genes but does not replicate in culture. After an initial decrease in the number of HCV positive cells, infection spread after 13–36 days. Sequencing of recovered viruses revealed non-homologous recombinants with J6 sequence from the 5′ end to the NS2–NS3 region followed by JFH1 sequence from Core to the 3′ end. These recombinants carried duplicated sequence of up to 2400 nucleotides. HCV replication was not required for recombination, as recombinants were observed in most experiments even when two replication incompetent genomes were co-transfected. Reverse genetic studies verified the viability of representative recombinants. After serial passage, subsequent recombination events reducing or eliminating the duplicated region were observed for some but not all recombinants. Furthermore, we found that inter-genotypic recombination could occur, but at a lower frequency than intra-genotypic recombination. Productive recombination of attenuated HCV genomes depended on expression of all HCV proteins and tolerated duplicated sequence. In general, no strong site specificity was observed. Non-homologous recombination was observed in most cases, while few homologous events were identified. A better understanding of HCV recombination could help identification of natural recombinants

Inhomogeneous bimolecular recombination in partially crystallised tri-methylphenyl diamine glasses

International Nuclear Information System (INIS)

Goldie, D.M.

2013-01-01

The rise and fall dynamics of transient photocurrents induced by exposure to ultraviolet radiation have been analysed for a series of glassy tri-methylphenyl diamine films that have been partially crystallised by ageing under ambient conditions following vapour deposition. An inhomogeneous bimolecular recombination model that uses coupled rate equations is found to provide a consistent fit for the observed photocurrent dynamics provided the recombination rate of holes in the crystallised regions of the films is lower compared to the amorphous regions. Parameters returned by the bimolecular model are investigated as a function of the film age but are observed to be highly sensitive to the initial experimental estimates that are supplied for the effective hole recombination time. The effective hole recombination time generated by the model is found to be relatively independent of film age, however, and has a value of around 0.16 s for a carrier generation rate of 7 × 10 14 cm −3 s −1 . The effective recombination time and steady-state photoconductivity magnitudes are found to be consistent with experimental hole mobility and photo-carrier generation efficiency values that are obtained using complementary time-of-flight and charge collection experiments. - Highlights: ► Transient photocurrents in evaporated diamine films have fast and slow components. ► Transient photocurrents are modelled using inhomogeneous bimolecular recombination. ► Recombination rates differ between crystallised and amorphous film regions. ► Recombination parameters evolve with film age as the films crystallise

Dielectronic recombination of highly ionized iron

International Nuclear Information System (INIS)

Griffin, D.C.; Pindzola, M.S.

1987-01-01

Dielectronic recombination of the iron ions Fe/sup 15+/, Fe/sup 23+/, and Fe/sup 25+/ has been studied in the isolated-resonance, distorted-wave approximation. The cross-section calculations include the dielec- tronic transitions associated with the 3s→3l and 3s→4l excitations in Fe/sup 15+/, the 2s→2p and 2s→3l excitations in Fe/sup 23+/, and the 1s→2l excitations in Fe/sup 25+/. The effects of external electric fields have been included by employing intermediate-coupled, field-mixed eigenvectors for the doubly excited Rydberg states, determined by diagonalizing a Hamiltonian matrix which includes the internal electrostatic and spin-orbit terms, as well as the Stark matrix elements. The field effects are found to be quite large in Fe/sup 15+/, relatively small in Fe/sup 23+/, and negligible in Fe/sup 25+/. The calculations indicate that there are large resonances near threshold in Fe/sup 23+/ that are unaffected by external fields and may be measurable in new experiments currently being designed. In addition, the contributions of radiative recombination and the possible interference between radiative and dielectronic recombination in low-lying resonances are considered. Even though the radiative recombination cross sections may be appreciable near threshold in Fe/sup 15+/ and Fe/sup 23+/, the interference between these processes appears to be completely negligible

Measurements of EEDF in recombination dominated afterglow plasma

Science.gov (United States)

Plasil, R.; Korolov, I.; Kotrik, T.; Varju, J.; Dohnal, P.; Donko, Z.; Bano, G.; Glosik, J.

2009-11-01

Electron energy distribution functions (EEDF) have been measured in decaying plasma in Flowing Afterglow Langmuir Probe (FALP) experiment. The measurements have been carried out in diffusion and recombination governed plasmas used for studies of recombination of KrD+ and H3+ ions.

Measurements of EEDF in recombination dominated afterglow plasma

International Nuclear Information System (INIS)

Plasil, R; Korolov, I; Kotrik, T; Varju, J; Dohnal, P; Glosik, J; Donko, Z; Bano, G

2009-01-01

Electron energy distribution functions (EEDF) have been measured in decaying plasma in Flowing Afterglow Langmuir Probe (FALP) experiment. The measurements have been carried out in diffusion and recombination governed plasmas used for studies of recombination of KrD + and H 3 + ions.

The Genetic Architecture of Natural Variation in Recombination Rate in Drosophila melanogaster.

Science.gov (United States)

Hunter, Chad M; Huang, Wen; Mackay, Trudy F C; Singh, Nadia D

2016-04-01

Meiotic recombination ensures proper chromosome segregation in many sexually reproducing organisms. Despite this crucial function, rates of recombination are highly variable within and between taxa, and the genetic basis of this variation remains poorly understood. Here, we exploit natural variation in the inbred, sequenced lines of the Drosophila melanogaster Genetic Reference Panel (DGRP) to map genetic variants affecting recombination rate. We used a two-step crossing scheme and visible markers to measure rates of recombination in a 33 cM interval on the X chromosome and in a 20.4 cM interval on chromosome 3R for 205 DGRP lines. Though we cannot exclude that some biases exist due to viability effects associated with the visible markers used in this study, we find ~2-fold variation in recombination rate among lines. Interestingly, we further find that recombination rates are uncorrelated between the two chromosomal intervals. We performed a genome-wide association study to identify genetic variants associated with recombination rate in each of the two intervals surveyed. We refined our list of candidate variants and genes associated with recombination rate variation and selected twenty genes for functional assessment. We present strong evidence that five genes are likely to contribute to natural variation in recombination rate in D. melanogaster; these genes lie outside the canonical meiotic recombination pathway. We also find a weak effect of Wolbachia infection on recombination rate and we confirm the interchromosomal effect. Our results highlight the magnitude of population variation in recombination rate present in D. melanogaster and implicate new genetic factors mediating natural variation in this quantitative trait.

Recombination in feline immunodeficiency virus from feral and companion domestic cats

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Rodrigo Allen G

2008-06-01

Full Text Available Abstract Background Recombination is a relatively common phenomenon in retroviruses. We investigated recombination in Feline Immunodeficiency Virus from naturally-infected New Zealand domestic cats (Felis catus by sequencing regions of the gag, pol and env genes. Results The occurrence of intragenic recombination was highest in env, with evidence of recombination in 6.4% (n = 156 of all cats. A further recombinant was identified in each of the gag (n = 48 and pol (n = 91 genes. Comparisons of phylogenetic trees across genes identified cases of incongruence, indicating intergenic recombination. Three (7.7%, n = 39 of these incongruencies were found to be significantly different using the Shimodaira-Hasegawa test. Surprisingly, our phylogenies from the gag and pol genes showed that no New Zealand sequences group with reference subtype C sequences within intrasubtype pairwise distances. Indeed, we find one and two distinct unknown subtype groups in gag and pol, respectively. These observations cause us to speculate that these New Zealand FIV strains have undergone several recombination events between subtype A parent strains and undefined unknown subtype strains, similar to the evolutionary history hypothesised for HIV-1 "subtype E". Endpoint dilution sequencing was used to confirm the consensus sequences of the putative recombinants and unknown subtype groups, providing evidence for the authenticity of these sequences. Endpoint dilution sequencing also resulted in the identification of a dual infection event in the env gene. In addition, an intrahost recombination event between variants of the same subtype in the pol gene was established. This is the first known example of naturally-occurring recombination in a cat with infection of the parent strains. Conclusion Evidence of intragenic recombination in the gag, pol and env regions, and complex intergenic recombination, of FIV from naturally-infected domestic cats in New Zealand was found. Strains

Recombination in feline immunodeficiency virus from feral and companion domestic cats.

Science.gov (United States)

Hayward, Jessica J; Rodrigo, Allen G

2008-06-17

Recombination is a relatively common phenomenon in retroviruses. We investigated recombination in Feline Immunodeficiency Virus from naturally-infected New Zealand domestic cats (Felis catus) by sequencing regions of the gag, pol and env genes. The occurrence of intragenic recombination was highest in env, with evidence of recombination in 6.4% (n = 156) of all cats. A further recombinant was identified in each of the gag (n = 48) and pol (n = 91) genes. Comparisons of phylogenetic trees across genes identified cases of incongruence, indicating intergenic recombination. Three (7.7%, n = 39) of these incongruencies were found to be significantly different using the Shimodaira-Hasegawa test.Surprisingly, our phylogenies from the gag and pol genes showed that no New Zealand sequences group with reference subtype C sequences within intrasubtype pairwise distances. Indeed, we find one and two distinct unknown subtype groups in gag and pol, respectively. These observations cause us to speculate that these New Zealand FIV strains have undergone several recombination events between subtype A parent strains and undefined unknown subtype strains, similar to the evolutionary history hypothesised for HIV-1 "subtype E".Endpoint dilution sequencing was used to confirm the consensus sequences of the putative recombinants and unknown subtype groups, providing evidence for the authenticity of these sequences. Endpoint dilution sequencing also resulted in the identification of a dual infection event in the env gene. In addition, an intrahost recombination event between variants of the same subtype in the pol gene was established. This is the first known example of naturally-occurring recombination in a cat with infection of the parent strains. Evidence of intragenic recombination in the gag, pol and env regions, and complex intergenic recombination, of FIV from naturally-infected domestic cats in New Zealand was found. Strains of unknown subtype were identified in all three gene

Expression and purification of recombinant nattokinase in Spodoptera frugiperda cells.

Science.gov (United States)

Li, Xiaoxiang; Wang, Xiaoli; Xiong, Shaoling; Zhang, Jing; Cai, Litao; Yang, Yanyan

2007-10-01

A recombinant baculovirus, rv-egfp-NK, containing a reporter gene encoding the enhanced green fluorescent protein (EGFP), was used to express nattokinase (NK), a fibrinolytic enzyme, in Spodoptera frugiperda (SF-9) cells. The recombinant protein also included a histidine tag for purification using Ni(2+) resins. The recombinant NK, approximately 30 kDa, retained fibrinolytic activity (60 U/ml). The integration of the EGFP expression cassette in the Bac-to-Bac system is thus an effective method for the expression and purification of recombinant NK protein in Spodoptera frugiperda insect cells.

Recombinant organisms for production of industrial products

OpenAIRE

Adrio, Jose-Luis; Demain, Arnold L

2009-01-01

A revolution in industrial microbiology was sparked by the discoveries of ther double-stranded structure of DNA and the development of recombinant DNA technology. Traditional industrial microbiology was merged with molecular biology to yield improved recombinant processes for the industrial production of primary and secondary metabolites, protein biopharmaceuticals and industrial enzymes. Novel genetic techniques such as metabolic engineering, combinatorial biosynthesis and molecular breeding...

Modelling of the operational behaviour of passive autocatalytic recombiners

International Nuclear Information System (INIS)

Schwarz, Ulrich

2011-01-01

Due to severe accidents in nuclear power plants, a significant amount of hydrogen can be produced. In pressurized water reactors, a possible and wide-spread measurement is the use of auto-catalytic recombiners. There are numerous numerical models describing the operational behaviour of recombiners for containment codes. The numerical model REKO-DIREKT was developed at the Forschungszentrum Juelich. This model describes the chemical reaction on the catalytic sheets by a physical model, as opposed to the usual codes based on empirical correlations. Additionally, there have been experimental studies concerning the catalytic recombination of hydrogen since the 1990s. The aim of this work is the further development of the program REKO-DIREKT to an independent recombiner model for severe accident and containment codes. Therefore, the catalyst model already existed has been submitted by a parameter optimization with an experimental database expanded during this work. In addition, a chimney model has been implemented which allows the calculation of the free convection flow through the recombiner housing due to the exothermal reaction. This model has been tested by experimental data gained by a recently built test facility. The complete recombiner model REKO-DIREKT has been validated by data from literature. Another aim of this work is the derivation of the reaction kinetics for recombiner designs regarding future reactor concepts. Therefore, experimental studies both on single catalytic coated meshes as well as on two meshes installed in a row have been performed in laboratory scale. By means of the measured data, a theoretical approach for the determination of the reaction rate has been derived.

On the Fokker-Planck theory of electron three-body recombination

International Nuclear Information System (INIS)

Sayasov, Yu. S.

1977-01-01

The Fokker-Planck theory of electron three-body recombination based on the concept of electron diffusion along the energy scale in the excited hydrogen-like atoms formed in the recombining plasmas, is extended in several respects. 1) An universal formula for population distribution of the excited atoms in strongly ionized plasmas was found under a sole assumption, that the cross-sections for the inelastic atom-electron collisions are governed by the classical impulse approximation. 2) A general Fokker-Planck theory of the recombination in a slightly ionized, two-temperature plasmas was formulated. The recombination coefficients for such plasmas were shown to possess some peculiar properties in case the electronic temperature differs appreciable from the atomic one. A few limitations of the existing schemas for calculation of the recombination kinetics are briefly discussed. (orig.) [de

Novel canine circovirus strains from Thailand: Evidence for genetic recombination.

Science.gov (United States)

Piewbang, Chutchai; Jo, Wendy K; Puff, Christina; van der Vries, Erhard; Kesdangsakonwut, Sawang; Rungsipipat, Anudep; Kruppa, Jochen; Jung, Klaus; Baumgärtner, Wolfgang; Techangamsuwan, Somporn; Ludlow, Martin; Osterhaus, Albert D M E

2018-05-14

Canine circoviruses (CanineCV's), belonging to the genus Circovirus of the Circoviridae family, were detected by next generation sequencing in samples from Thai dogs with respiratory symptoms. Genetic characterization and phylogenetic analysis of nearly complete CanineCV genomes suggested that natural recombination had occurred among different lineages of CanineCV's. Similarity plot and bootscaning analyses indicated that American and Chinese viruses had served as major and minor parental viruses, respectively. Positions of recombination breakpoints were estimated using maximum-likelihood frameworks with statistical significant testing. The putative recombination event was located in the Replicase gene, intersecting with open reading frame-3. Analysis of nucleotide changes confirmed the origin of the recombination event. This is the first description of naturally occurring recombinant CanineCV's that have resulted in the circulation of newly emerging CanineCV lineages.

Charge carrier recombination dynamics in perovskite and polymer solar cells

Energy Technology Data Exchange (ETDEWEB)

Paulke, Andreas; Kniepert, Juliane; Kurpiers, Jona; Wolff, Christian M.; Schön, Natalie; Brenner, Thomas J. K.; Neher, Dieter [Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24–25, 14476, Potsdam (Germany); Stranks, Samuel D. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Snaith, Henry J. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)

2016-03-14

Time-delayed collection field experiments are applied to planar organometal halide perovskite (CH{sub 3}NH{sub 3}PbI{sub 3}) based solar cells to investigate charge carrier recombination in a fully working solar cell at the nanosecond to microsecond time scale. Recombination of mobile (extractable) charges is shown to follow second-order recombination dynamics for all fluences and time scales tested. Most importantly, the bimolecular recombination coefficient is found to be time-dependent, with an initial value of ca. 10{sup −9} cm{sup 3}/s and a progressive reduction within the first tens of nanoseconds. Comparison to the prototypical organic bulk heterojunction device PTB7:PC{sub 71}BM yields important differences with regard to the mechanism and time scale of free carrier recombination.

Construction and Characterization of a Recombinant Invertebrate Iridovirus

NARCIS (Netherlands)

Ozgen, A.; Muratoglu, H.; Demirbag, Z.; Vlak, J.M.; Oers, van M.M.; Nalcacioglu, R.

2014-01-01

Chilo iridescent virus (CIV), officially named Insect iridescent virus 6 (IIV6), is the type species of the genus Iridovirus (family Iridoviridae). In this paper we constructed a recombinant CIV, encoding the green fluorescent protein (GFP). This recombinant can be used to investigate viral

Measurements of EEDF in recombination dominated afterglow plasma

Energy Technology Data Exchange (ETDEWEB)

Plasil, R; Korolov, I; Kotrik, T; Varju, J; Dohnal, P; Glosik, J [Charles University, Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Prague (Czech Republic); Donko, Z; Bano, G, E-mail: radek.plasil@mff.cuni.c [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Budapest (Hungary)

2009-11-15

Electron energy distribution functions (EEDF) have been measured in decaying plasma in Flowing Afterglow Langmuir Probe (FALP) experiment. The measurements have been carried out in diffusion and recombination governed plasmas used for studies of recombination of KrD{sup +} and H{sub 3}{sup +} ions.

Recombination Phenotypes of Escherichia coli greA Mutants

Directory of Open Access Journals (Sweden)

Poteete Anthony R

2011-03-01

Full Text Available Abstract Background The elongation factor GreA binds to RNA polymerase and modulates transcriptional pausing. Some recent research suggests that the primary role of GreA may not be to regulate gene expression, but rather, to promote the progression of replication forks which collide with RNA polymerase, and which might otherwise collapse. Replication fork collapse is known to generate dsDNA breaks, which can be recombinogenic. It follows that GreA malfunction could have consequences affecting homologous recombination. Results Escherichia coli mutants bearing substitutions of the active site acidic residues of the transcription elongation factor GreA, D41N and E44K, were isolated as suppressors of growth inhibition by a toxic variant of the bacteriophage lambda Red-beta recombination protein. These mutants, as well as a D41A greA mutant and a greA deletion, were tested for proficiency in recombination events. The mutations were found to increase the efficiency of RecA-RecBCD-mediated and RecA-Red-mediated recombination, which are replication-independent, and to decrease the efficiency of replication-dependent Red-mediated recombination. Conclusion These observations provide new evidence for a role of GreA in resolving conflicts between replication and transcription.

21 CFR 522.2630 - Tulathromycin.

Science.gov (United States)

2010-04-01

.... multocida, Bordetella bronchiseptica, Haemophilus parasuis, and Mycoplasma hyopneumoniae; and for the control of SRD associated with A. pleuropneumoniae, P. multocida, and M. hyopneumoniae in groups of pigs..., Histophilus somni, and Mycoplasma bovis. For the control of respiratory disease in cattle at high risk of...

The Genetic Architecture of Natural Variation in Recombination Rate in Drosophila melanogaster.

Directory of Open Access Journals (Sweden)

Chad M Hunter

2016-04-01

Full Text Available Meiotic recombination ensures proper chromosome segregation in many sexually reproducing organisms. Despite this crucial function, rates of recombination are highly variable within and between taxa, and the genetic basis of this variation remains poorly understood. Here, we exploit natural variation in the inbred, sequenced lines of the Drosophila melanogaster Genetic Reference Panel (DGRP to map genetic variants affecting recombination rate. We used a two-step crossing scheme and visible markers to measure rates of recombination in a 33 cM interval on the X chromosome and in a 20.4 cM interval on chromosome 3R for 205 DGRP lines. Though we cannot exclude that some biases exist due to viability effects associated with the visible markers used in this study, we find ~2-fold variation in recombination rate among lines. Interestingly, we further find that recombination rates are uncorrelated between the two chromosomal intervals. We performed a genome-wide association study to identify genetic variants associated with recombination rate in each of the two intervals surveyed. We refined our list of candidate variants and genes associated with recombination rate variation and selected twenty genes for functional assessment. We present strong evidence that five genes are likely to contribute to natural variation in recombination rate in D. melanogaster; these genes lie outside the canonical meiotic recombination pathway. We also find a weak effect of Wolbachia infection on recombination rate and we confirm the interchromosomal effect. Our results highlight the magnitude of population variation in recombination rate present in D. melanogaster and implicate new genetic factors mediating natural variation in this quantitative trait.

The Contribution of Genetic Recombination to CRISPR Array Evolution.