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1.
Mycobacterium tuberculosis H37Ra,M. smegmatisATCC 607,M. smegmatis MC2155,M. aurum A +,M. aurum A11, and one representative strain ofM. flavescens were transformed by electroporation with plasmid pMY10 and cosmid pDC100. Plasmid pMY 10 contained the origin of replication of pAL5000, the origin of replication of pBR322, a kanamycin resistance gene, and the origin of transfer of the Inc plasmid RK2; the cosmid pDC100 contained the pHC79 SS cosmid, the origin of replication of pAL5000, and a kanamycin resistance gene. The efficiency of transformation varied with the recipient cells used and was in decreasing order: 7×105 forM. smegmatis MC2155, 6×103 forM. tuberculosis H37Ra, 103 forM. aurum, 50 forM. smegmatis ATCC 607, and 5 forM. flavescens. A rapid protocol for plasmid extraction from mycobacteria was developed.The satisfactory transformation of the nonvirulentM. tuberculosis strain H37Ra was of interest for future studies on cloning of virulence genes, while the satisfactory transformation ofM. aurum was of interest for future studies on the genetics of drug resistance because these bacteria are sensitive to drugs specifically used in the treatment of tuberculosis and leprosy. However, neither vector was stably maintained inM. smegmatis, indicating that further investigations are still necessary to resolve this difficulty. 相似文献
2.
MORBILLIVIRUS INFECTION IN BOTTLENOSE DOLPHINS: EVIDENCE FOR RECURRENT EPIZOOTICS IN THE WESTERN ATLANTIC AND GULF OF MEXICO 总被引:1,自引:0,他引:1
Pádraig J. Duignan Carol House Daniel K. Odell Randall S. Wells Larry J. Hansen Michael T. Walsh David J. St . Aubin Bert K. Rima Joseph R. Geraci 《Marine Mammal Science》1996,12(4):499-515
Morbillivirus infection is widespread among odontocetes of the western Atlantic and Gulf of Mexico. Serologic evidence of infection in bottlenose dolphins, Tursiops truncatus , was first detected during an epizootic along the mid-Atlantic coast in 1987. Here, we report recurrent epizootics in the coastal dolphin population since at least the early 1980s based on serological surveys and regional stranding frequencies. The first observed epizootic of this series occurred in the Indian and Banana Rivers in 1982 and was followed by others on the mid-Atlantic coast in 1987–1988 and in the Gulf of Mexico between 1992 and 1994. This temporal pattern of infection is likely facilitated by the population size and its fragmentation into relatively discrete coastal communities. Introduction of morbillivirus into a community with a sufficient number of naive hosts may precipitate an epizootic, depending on the potential for transmission within the group. Propagation of an epizootic along the coast is probably determined by frequency of contact between adjacent communities and seasonal migrations.
Morbillivirus antibodies were also detected in serum from offshore bottlenose dolphins. The sero-prevalence in the latter may be higher than in coastal dolphins because of their close association with enzootically infected pilot whales ( Globicephala spp.). Occasional contact between offshore and coastal dolphins may provide an epizootiologic link between pilot whales and coastal dolphin communities. 相似文献
Morbillivirus antibodies were also detected in serum from offshore bottlenose dolphins. The sero-prevalence in the latter may be higher than in coastal dolphins because of their close association with enzootically infected pilot whales ( Globicephala spp.). Occasional contact between offshore and coastal dolphins may provide an epizootiologic link between pilot whales and coastal dolphin communities. 相似文献
3.
Antigenic determinants of measles virus hemagglutinin associated with neurovirulence. 总被引:7,自引:5,他引:2 下载免费PDF全文
U G Liebert S G Flanagan S Lffler K Baczko V ter Meulen B K Rima 《Journal of virology》1994,68(3):1486-1493
The biological activity of monoclonal antibodies specific for the hemagglutinin protein of measles virus strain CAM recognizing six epitope groups according to their binding properties to measles virus strain CAM/R401 was investigated in vivo in our rat model of measles encephalitis. When injected intraperitoneally into measles virus-infected suckling rats, some monoclonal antibodies modified the disease process and prevented the necrotizing encephalopathy seen in untreated animals. The analysis of measles virus brain isolates revealed emergence of variants that resisted neutralization with the passively transferred selecting monoclonal antibody but not with other monoclonal antibodies. Monoclonal antibody escape mutants were also isolated in vitro, and their neurovirulence varied in the animal model. Sequence data from the hemagglutinin gene of measles virus localize a major antigenic surface determinant of the hemagglutinin protein between amino acid residues 368 and 396, which may be functionally important for neurovirulence. The data indicate that the interaction of antibodies with the measles virus H protein plays an important role in the selection of neurovirulent variants. These variants have biological properties different from those of the parent CAM virus. 相似文献
4.
Bacanamwo Methode; Purcell Larry C.; Serraj Rachid 《Journal of experimental botany》1997,48(11):1987-1994
Regulation of nitrogen fixation in response to various environmentalconditions often involves an adjustment in nodule permeabilityand, because of the importance of nodule permeability in nitrogenfixation, several methods to estimate it have been developed.In the present study, these methods are reviewed and their limitationsare highlighted. A simple, rapid and inexpensive technique thatcan be used to estimate permeability of nodules and respirationof other plant tissues is described. The technique was evaluatedby comparing it to the lag-phase technique as an independentand reliable method for estimating nodule permeability. Overa wide range of nodule permeability estimates, the closed systemO2 uptake technique was linearly related to lag-phase permeabilityestimates. The technique was tested further by studying theresponse to sub- and supra-ambient pO2 in the root environment,and the responses agreed well with published reports on theeffect of O2 on nodule permeability. The technique was foundto be very satisfactory in estimating nodule permeability andmay be used to measure the ability of other plant tissues totake up O2. Key words: Soybean, Glycine max, nitrogen fixation, root, respiration 相似文献
5.
In Bacillus subtilis, uracil (Ura), uridine (Urd), and deoxyuridine (dUrd) are metabolized through pathways similar to those of enteric bacteria. Ura is probably converted to uridine 5'-monophosphate by uridine 5'-monophosphate pyrophosphorylase. More than 95% of dUrd added to cultures is converted to Ura and deoxyribose-1-phosphate. Although dUrd kinase activity is detectable in vitro, this enzyme does not seem to play an important role in the metabolism of dUrd. The metabolism of cytosine (Cyt), cytidine (Cyd), and deoxycytidine (dCyd) in B. subtilis appears to be different from that in enteric bacteria. Cytosine cannot be used by Ura-requiring mutants as pyrimidine source. dCyd is deaminated by dCyd-Cyd deaminase or phosphorylated to dCyd nucleotides by dCyd kinase. Cyd is deaminated by dCyd-Cyd deaminase of phosphorylated by Cyd kinase. This Cyd kinase activity has never been reported for B. subtilis. 相似文献
6.
A number of deoxyribonucleoside-requiring mutants (dns) of Bacillus subtilis were isolated and their growth characteristics and ribonucleotide reductase activities were compared with those of the wild type and of a dna mutant (tsA13). Both tsA13 and dns mutants required the presence of a mixture of deoxyribonucleosides for growth at 45 degrees C but not at 25 degrees C. All the mutant strains tested contained ribonucleotide reductase activity which showed heat sensitivity similar to that of the enzyme from a wild-type strain. The reductase in B. subtilis seemed to reduce ribonucleoside triphosphates in a similar manner to the enzyme in Lactobacillus leichmannii. 相似文献
7.
8.
Rachid Zerrouki Traki Benhassine Mustapha Bensaada Patricia Lauzon Anissa Trabzi 《Genetics and molecular biology》2016,39(1):7-13
Many subtypes of acute lymphoblastic leukemia (ALL) are associated with specific chromosomal rearrangements. The complex translocation t(9;14;14), a variant of the translocation (14;14)(q11;q32), is a rare but recurrent chromosomal abnormality involving the immunoglobulin heavy-chain (IGH) and CCAAT enhancer-binding protein (CEBPE) genes in B-lineage ALL (B-ALL) and may represent a new B-ALL subgroup. We report here the case of a 5-year-old girl with B-ALL, positive for CD19, CD38 and HLA-DR. A direct technique and G-banding were used for chromosomal analysis and fluorescentin situ hybridization (FISH) with BAC probes was used to investigate a possible rearrangement of the IGH andCEBPE genes. The karyotype exhibit the chromosomal aberration 46,XX,del(9)(p21),t(14;14)(q11;q32). FISH with dual-color break-apartIGH-specific and CEPBE-specific bacterial artificial chromosome (BAC) probes showed a complex t(9;14;14) associated with a deletion of cyclin-dependent kinase inhibitor 2A (CDKN2A) and paired box gene 5 (PAX5) at 9p21-13 and duplication of the fusion gene IGH-CEBPE. 相似文献
9.
Short-term effects of water deficit on nitrogenase activitywere investigated with hydroponically grown soybean plants (Glycinemax L. Merr. cv. Biloxi) by adding polyethylene glycol (PEG)to the hydroponic solution and measuring nitrogenase activity,nodule respiration, and permeability to oxygen diffusion (Po).These experiments showed a rapid decrease in acetylene reductionactivity (ARA) and nodule respiration. A consequence of thedecreased respiration rate was that Po calculated by Fick'sLaw also decreased. However, these results following PEG treatmentwere in direct conflict with a previous report of stabilityin Po determined by using an alternative technique. To resolvethis conflict, an hypothesis describing a sequence of responsesto the initial PEG treatment is presented. An important findingof this study was that the response to water deficit inducedby PEG occurred in two stages. The first stage of decreasednodule activity was O2-limited and could be reversed by exposingthe nodules to elevated pO2. The second stage which developedafter 24 h of exposure to PEG resulted in substantial loss innodule activity and this activity could not be recovered withincreased pO2. Severe water deficit treatments disrupt noduleactivity to such a degree that O2 is no longer the major limitation. Key words: Glycine max, N2 fixation, soybean, oxygen permeability, water deficit 相似文献
10.
Koura Jessica Manneh Rima Belarbi Rafik El Khoury Vanessa El Bachawati Makram 《The International Journal of Life Cycle Assessment》2020,25(3):423-442
The International Journal of Life Cycle Assessment - Vegetative roofs (VRs) are fully planted roof spaces that offer aesthetic view, storm water management, sound insulation, energy savings, and... 相似文献