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1.
Naumov GI Naumova ES Aigle M Masneuf I Belarbi A 《Applied microbiology and biotechnology》2001,55(1):108-111
Using genetic hybridization analysis, pulsed-field gel electrophoresis of chromosomal DNA and PCR/RFLP analysis of the MET2 gene, we reidentified 11 Champagne yeast strains. Two of them, SCPP and SC4, were found to belong to Saccharomyces bayanus var. uvarum and the remaining strains to S. cerevisiae. Strain SCPP (CLIB 2025) of S. bayanus var. uvarum is known as a producer of three pectinolytic enzymes.
Received: 28 April 2000 / Received revision: 20 July 2000 / Accepted: 25 July 2000 相似文献
2.
This short review covers metabolic pathways, genetics and metabolic engineering of 1,2-propanediol formation in microbes.
1,2-Propanediol production by bacteria and yeasts has been known for many years and two general pathways are recognized. One
involves the metabolism of deoxyhexoses, where lactaldehyde is formed during the glycolytic reactions and is then reduced
to 1,2-propanediol. The second pathway derives from the formation of methylglyoxal from dihydroxyacetonephosphate and its
subsequent reduction to 1,2-propanediol. The enzymes involved in the reduction of methylglyoxal can generate isomers of lactaldehyde
or acetol, which can be further reduced by specific reductases, giving chiral 1,2-propanediol as the product. The stereospecificity
of the enzymes catalyzing the two reduction steps is important in deriving a complete pathway. Through genetic engineering,
appropriate combinations of enzymes have been brought together in Escherichia coli and yeast to generate 1,2-propanediol from glucose. The optimization of these strains may yield microbial processes for the
production of this widely used chemical.
Received: 25 May 2000 / Received revision: 24 July 2000 / Accepted: 25 July 2000 相似文献
3.
Rhizobium leguminosarum biovar trifolii was detected in soil from 41 of 47 plots, within nine sewage sludge-treated sites with different soil characteristics and
heavy metal contents. However, although population size varied widely, there was no consistent correlation with soil heavy
metal concentration. Indigenous populations in 20 plots within four selected sites retained their ability to induce effective
nodule formation after incubation of soil in the dark for 165 days. In sterilized (γ-irradiated) soil, Rhizobium survival varied from 0.01% to 95% depending on the soil sample and strain used. Metal-resistant strains with non-mucoid colonies
survived less well than mucoid metal-sensitive strains.
Received: 26 June 2000/Accepted: 31 July 2000 相似文献
4.
Fuller ME Mailloux BJ Streger SH Hall JA Zhang P Kovacik WP Vainberg S Johnson WP Onstott TC DeFlaun MF 《Applied and environmental microbiology》2004,70(3):1680-1687
Two differentially labeled bacterial strains were monitored in near-real time during two field-scale bacterial transport experiments in a shallow aquifer in July 2000 and July 2001. Comamonas sp. strain DA001 and Acidovorax sp. strain OY-107 were grown and labeled with the vital fluorescent stain TAMRA/SE (5 [and -6]-carboxytetramethylrhodamine, succinimidyl ester) or CFDA/SE (5 [and -6]-carboxyfluorescein diacetate, succinimidyl ester). Fluorescently labeled cells and a conservative bromide tracer were introduced into a suboxic superficial aquifer, followed by groundwater collection from down-gradient multilevel samplers. Cells were enumerated in the field by microplate spectrofluorometry, with confirmatory analyses for selected samples done in the laboratory by epifluorescence microscopy, flow cytometry, and ferrographic capture. There was general agreement in the results from all of the vital-stain-based enumeration methods, with differences ranging from <10% up to 40% for the analysis of identical samples between different tracking methods. Field analysis by microplate spectrofluorometry was robust and efficient, allowing thousands of samples to be analyzed in quadruplicate for both of the injected strains. The near-real-time data acquisition allowed adjustments to the predetermined sampling schedule to be made. The microplate spectrofluorometry data sets for the July 2000 and July 2001 experiments allowed the transport of the injected cells to be related to the site hydrogeology and injection conditions and enabled the assessment of differences in the transport of the two strains. This near-real-time method should prove effective for a number of microbial ecology applications. 相似文献
5.
Twenty nodule isolates from Sarothamnus scoparius (broom) growing in Poland and nine strains from plants growing in Japan were studied for phenotypic properties, plasmid presence,
phage sensitivity, and host plant specificity. By numerical analysis of phenotypic properties, it was found that the studied
nodule bacteria, originating from geographically different countries, constitute two separate groups affiliated to the bradyrhizobium
cluster. The membership of S. scoparius rhizobia in the Bradyrhizobium genus was also supported by their long generation time, alkaline reaction in YEM medium with mannitol, lack of plasmids,
and wide host plant range.
Received: 12 June 2000 / Accepted: 17 July 2000 相似文献
6.
The xylose reductase gene (XYL1) was isolated from Pichia stipitis and Candida shehatae, cloned into YEp-based vectors under the control of ADH2 and PGK1 promoter/terminator cassettes and introduced into Saccharomyces cerevisiae Y294 by electroporation. Shake-flask fermentations were carried out with 5% xylose and 1% galactose, glucose or maltose as
co-substrates. Xylose uptake was similar in both the recombinant strains when different co-substrates were used and slowed
once the co-substrate was depleted. The recombinant strains converted xylose to xylitol with yields approaching the theoretical
maxima. Xylitol production was most rapid when the co-substrate was still present. Approximately 50% of the xylose was not
metabolized due to the depletion of the co-substrate.
Received: 23 December 1999 / Received revision: 30 June 2000 / Accepted: 1 July 2000 相似文献
7.
Application of a Vital Fluorescent Staining Method for Simultaneous, Near-Real-Time Concentration Monitoring of Two Bacterial Strains in an Atlantic Coastal Plain Aquifer in Oyster, Virginia 下载免费PDF全文
Mark E. Fuller Brian J. Mailloux Sheryl H. Streger James A. Hall Pengfei Zhang William P. Kovacik Simon Vainberg William P. Johnson Tullis C. Onstott Mary F. DeFlaun 《Applied microbiology》2004,70(3):1680-1687
Two differentially labeled bacterial strains were monitored in near-real time during two field-scale bacterial transport experiments in a shallow aquifer in July 2000 and July 2001. Comamonas sp. strain DA001 and Acidovorax sp. strain OY-107 were grown and labeled with the vital fluorescent stain TAMRA/SE (5 [and -6]-carboxytetramethylrhodamine, succinimidyl ester) or CFDA/SE (5 [and -6]-carboxyfluorescein diacetate, succinimidyl ester). Fluorescently labeled cells and a conservative bromide tracer were introduced into a suboxic superficial aquifer, followed by groundwater collection from down-gradient multilevel samplers. Cells were enumerated in the field by microplate spectrofluorometry, with confirmatory analyses for selected samples done in the laboratory by epifluorescence microscopy, flow cytometry, and ferrographic capture. There was general agreement in the results from all of the vital-stain-based enumeration methods, with differences ranging from <10% up to 40% for the analysis of identical samples between different tracking methods. Field analysis by microplate spectrofluorometry was robust and efficient, allowing thousands of samples to be analyzed in quadruplicate for both of the injected strains. The near-real-time data acquisition allowed adjustments to the predetermined sampling schedule to be made. The microplate spectrofluorometry data sets for the July 2000 and July 2001 experiments allowed the transport of the injected cells to be related to the site hydrogeology and injection conditions and enabled the assessment of differences in the transport of the two strains. This near-real-time method should prove effective for a number of microbial ecology applications. 相似文献
8.
Antibacterial activity of 17 strains of lactobacilli was tested against 10 strains of H. pylori. The inhibition observed was related to the acid production and the low pH attained. No relationship between CagA phenotype
of H. pylori strains and tolerance to lactic acid was observed. In mixed cultures, L. acidophilus CRL 639 showed an autolytic behavior after 24 h of culture. At this moment, H. pylori CCUG17874 showed a decrease of 2 log-cycle, and no viable count was detected after 48 h. The bactericidal effect of L. acidophilus CRL 639 in mixed cultures is related to a proteinaceous compound released after cell lysis.
Received: 19 June 2000 / Accepted: 12 July 2000 相似文献
9.
Twenty-five strains of Lactococcus lactis subspecies lactis and subspecies cremoris obtained from dairy industry and environmental collections were examined by 16S RNA automated ribotyping profiles and site-specific
PCR (S-PCR). By automated ribotyping, the majority of strains were classified in accordance with phenotypic characterization,
with the exception of one lactis (220) and two cremoris (BO32 and 140) strains. A complete differentiation of subspecies lactis and cremoris in agreement with conventional phenotypic methods was achieved by S-PCR with a set of site-specific primer pairs (PR1, RM4,
and F3) designed particularly from a deletion region found in subspecies cremoris, but not in lactis. Therefore, S-PCR with primers (PR1, RM4, and F3) is a rapid and very sensitive method for the distinction of lactis and cremoris subspecies in dairy production.
Received: 19 June 2000 / Accepted: 17 July 2000 相似文献
10.
DNases were shown to be present in the extracellular fraction of Frankia strains R43 and CcI3. In spite of this, DNA was found in both the extracellular and cell wall fractions of these strains,
and it was shown that extracellular DNA was resistant to the DNases secreted into the culture medium of both Frankia strains. Furthermore, Southern blot analysis under high stringency conditions revealed the chromosomal origin of the cell
wall-adsorbed DNA (CW-DNA). Mobility gel band shift assays suggested that the extracellular DNA and the CW-DNA are engaged
in complexes with other molecules, most likely proteins, which are probably responsible for the enzymatic resistance observed
against extracellular DNase activities. In addition, it was shown that lysis of a small proportion of the cells in the exponential
growth phase may account for the DNA being released into the supernatant and adsorbed to the cell wall.
Received: 21 July 2000 / Accepted: 21 August 2000 相似文献
11.
Inglis PW Teixeira EA Ribeiro DM Valadares-Inglis MC Tigano MS Mello SC 《Current microbiology》2001,42(3):194-198
Cercospora caricis is of interest as a potential mycoherbicide for control of purple nutsedge, Cyperus rotundus, which is considered to be the world's worst weed. The genetic variation of a collection of Brazilian Ce. caricis isolated from Cy. rotundus was analyzed by using RAPD, RFLP with a telomeric probe, [TTAGGG]18 and sequencing of the ITS1-5.8S-ITS2 regions of the ribosomal RNA gene. The Brazilian isolates were also compared with a
Ce. caricis isolate from Florida, USA and with some other Cercospora species. A cluster of isolates from the Brazilian cerrado region was identified showing high genetic similarity. In contrast,
isolates originating in other geographic regions of Brazil were less than 50% and 25% related to the former group according
to similarity estimates produced from RAPD and telomeric RFLP analyses respectively. ITS sequence analysis did not support
taxonomic division of the Brazilian strains, but did confirm the distant relatedness of these strains to the Ce. caricis isolate from Florida. The data indicate a need for an extensive molecular survey of Cercospora species associated with the Cyperaceae.
Received: 12 July 2000 / Accepted: 5 September 2000 相似文献
12.
Słomka M Szymanowska A Rokosz A Sawicka-Grzelak A Luczak M 《Medycyna do?wiadczalna i mikrobiologia》2004,56(2):127-131
The aim of this study was to compare the results of two methods: disc-diffusion test and ATB STAPH 5 (version 2000) test applied for determination of methicillin-resistant staphylococci. One hundred and twenty S. aureus strains isolated from clinical specimens in microbiological laboratory of Medical University in Warsaw were investigated. Identification and drug resistance were determined using automatic ATB Expression System. We compared the results of methicillin-resistant S. aureus detection by disc-diffusion method (oxacillin 1 microg) and ATB STAPH 5; version 2000 (bioMérieux sa). In the case of 116 strains S. aureus identical results were obtained in both methods, 4 strains gave inconsistent results in these two methods. Results that were obtained show that the ATB STAPH 5 (version 2000) test is as useful for routine determination of MRSA and MSSA strains as the disc-diffusion method, and may be used alternatively. 相似文献
13.
Anaerobic sequencing batch reactors for wastewater treatment: a developing technology 总被引:4,自引:0,他引:4
Zaiat M Rodrigues JA Ratusznei SM de Camargo EF Borzani W 《Applied microbiology and biotechnology》2001,55(1):29-35
This paper describes and discusses the main problems related to anaerobic batch and fed-batch processes for wastewater treatment.
A critical analysis of the literature evaluated the industrial application viability and proposed alternatives to improve
operation and control of this system. Two approaches were presented in order to make this anaerobic discontinuous process
feasible for industrial application: (1) optimization of the operating procedures in reactors containing self-immobilized
sludge as granules, and (2) design of bioreactors with inert support media for biomass immobilization.
Received: 22 May 2000 / Received revision: 20 July 2000 / Accepted: 21 July 2000 相似文献
14.
Singleton MR Taylor SJ Parrat JS Littlechild JA 《Extremophiles : life under extreme conditions》2000,4(5):297-303
The gene encoding pyrrolidone carboxyl peptidase (Pcp) has been cloned from the hyperthermophilic archaeon Thermococcus litoralis. The recombinant enzyme has been expressed in Escherichia coli, purified, and char-acterized. The T. litoralis Pcp demonstrates strong sequence homology to previously characterized bacterial Pcps. Some investigations have been carried
out on enzyme substrate specificity and stability.
Received: July 4, 2000 / Accepted: July 21, 2000 相似文献
15.
S. González J. Díaz M. S. Pajares J. C. Alberdi A. Otero C. López 《International journal of biometeorology》2001,45(1):34-40
This study set out to determine the possible influence of variations in atmospheric pressure on mortality in the Madrid Autonomous
Region (MAR), taking into account the possible confounding effect of other atmospheric variables. The study was based on daily
mortality data from the MAR Revenue and Excise Authority, meteorological data from Getafe Observatory and air pollution data
from the Madrid Municipal Automatic Air Pollution Monitoring Grid. A time-series analysis was performed, using Box-Jenkins
modelling and controlling for the respective confounding variables. Furthermore, the different variables studied (pressure,
temperature, pollutants, etc.) were used to produce a multivariate model of the different causes of mortality. A significant
association was found between anticyclonic trend and mortality with circulatory causes in the medium-long term and anticyclonic
trend and mortality with respiratory causes in the long term.
Received: 14 January 2000 / Revised: 5 July 2000 / Accepted: 10 July 2000 相似文献
16.
Effects of ENU dosage on mouse strains 总被引:15,自引:0,他引:15
Monica J. Justice Don A. Carpenter Jack Favor Angelika Neuhauser-Klaus Martin Hrabé de Angelis Dian Soewarto Amy Moser Sabine Cordes Darla Miller Verne Chapman John S. Weber Eugene M. Rinchik Patricia R. Hunsicker William L. Russell Vernon C. Bode 《Mammalian genome》2000,11(7):484-488
The germline supermutagen, N-ethyl-N-nitrosourea (ENU), has a variety of effects on mice. ENU is a toxin and carcinogen as well as a mutagen, and strains differ
in their susceptibility to its effects. Therefore, it is necessary to determine an appropriate mutagenic, non-toxic dose of
ENU for strains that are to be used in experiments. In order to provide some guidance, we have compiled data from a number
of laboratories that have exposed male mice from inbred and non-inbred strains or their F1 hybrids to ENU. The results show that most F1 hybrid animals tolerate ENU well, but that inbred strains of mice vary in their longevity and in their ability to recover
fertility after treatment with ENU.
Received: 11 February 2000 / Accepted: 11 February 2000 相似文献
17.
A. D. FOX D. G. SALMON 《Biological journal of the Linnean Society. Linnean Society of London》1994,51(1-2):237-245
Aerial and ground censuses of Shelduck in 1988 found a summering population of 2000–2700 birds until early July. Territorial pairs, non-breeding aggregations and ultimate brood rearing nursery areas were associated with extensive areas of mudflats (Peterstone Wentlooge, Uskmouth-Collister Pill, Oldbury-Littleton and Purton-Frampton). Bridgwater Bay continues to be the most important moulting area away from the Wadden Sea, with just under 2000 present at peak count in late July. At least 94 pairs established territories along the shores of the Severn, with perhaps as many as 80 more on Flatholm, giving rise to at least 49 broods. Duckling survival was low in 1988: mean brood size fell from 9.3 to 3.3 between hatching and fledging. Breeding success in different parts of the estuary shows no consistent trends. 相似文献
18.
Swedish soil isolates biochemically classified as Bacillus thuringiensis subsp. israelensis were further examined for genetic diversity by multilocus enzyme electrophoresis (MLEE), random amplified polymorphic DNA
analysis (RAPD), pulse field gel electrophoresis (PFGE), and Southern blotting, and were compared with reference strains.
All the tested strains belonging to the Bt. israelensis serotype H14 were found to be identical, as judged from the RAPD analysis. MLEE analysis gave a similar result; only one
H14 strain was found to differ from the remaining H14 strains by one null allele. PFGE analysis confirmed a very close relationship
between the H14 strains but revealed an SfiI restriction fragment of variable size. Southern blot analyses were carried out with probes for the chromosomally encoded
flagellin gene(s) and the plasmid-encoded mosquitocidal toxins. All probes gave similar hybridization patterns in the H14
strains. The mosquito toxin probes hybridized only to the H14 strains, except for one probe hybridizing to strain 6:3, which
was originally isolated from the same soil sample as strains 6:11 and 6:12. Because the RAPD, MLEE, and PFGE analyses showed
that strain 6:3 appears to be unrelated to strains 6:11 and 6:12, the presence of a mosquito toxin sequence in strain 6:3
may suggest that gene transfer has occurred.
Received: 8 July 1999 / Accepted: 9 August 1999 相似文献
19.
Selection for high seed oil content in soybean families derived from plants regenerated from protoplasts and tissue cultures 总被引:2,自引:0,他引:2
M. V. Nguyen C. D. Nickell J. M. Widholm 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(6-7):1072-1075
Recurrent selection for high seed oil content was carried out with 2,008 progeny of 28 plants regenerated via embryogenesis,
95 via organogenesis and 25 from protoplasts via organogenesis from five different soybean cultivars. Two lines derived from
plants regenerated from the cultivar Jack with small increases in seed oil content emerged after three selection cycles in
the field but in both cases the protein content was decreased and the seed yield of one of the lines was also decreased. Apparently
somaclonal variation for seed oil content can arise, but on the basis of the decreases in protein and yield found in this
study, this small change is not useful for soybean improvement.
Received: 22 July 2000 / Accepted: 28 July 2000 相似文献
20.
The interaction between light and gravity is critical in determining the final form of a plant. For example, the competing
activities of gravitropism and phototropism can determine the final orientation of a stem or root. The results reported here
indicate that, in addition to the previously described blue-light-dependent negative phototropic response in roots, roots
of Arabidopsis thaliana (L.) Heynh. display a previously unknown red-light-dependent positive phototropic response. Both phototropic responses in
roots are considerably weaker than the graviresponse, which often masks phototropic curvature. However, through the use of
mutant strains with impaired gravitropism, we were able to identify a red-light-dependent positive phototropic response in
Arabidopsis roots. The red-induced positive phototropic response is considerably weaker than the blue-light response and is barely detectable
in plants with a normal gravitropic response.
Received: 22 May 2000 / Accepted: 3 July 2000 相似文献