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1.
Zearalenone (ZON) is a non-steroidal estrogenic mycotoxin produced by plant pathogenic species ofFusarium. As a consequence of infection withF. culmorum andF. graminearum, ZON can be found in cereals and derived food products. Several countries have established monitoring programs and guidelines
for ZON levels in grain intended for human consumption and animal feed. We have developed a sensitive yeast bioassay allowing
detection of the estrogenic activity of ZON in cereal extracts without requiring further clean up steps. The high sensitivity
makes this assay suitable for low cost monitoring of contamination of small grain cereals with estrogenicFusarium mycotoxins, but also attractive as a tool for basic research. We have successfully used yeast indicator strains to screen
for mutants ofF. graminearum which no longer produce detectable amounts of ZON, and have identified a plant cDNA encoding a ZON detoxification enzyme.
Presented at the 25th Mykotoxin Workshop in Giessen, Germany, May 19–21, 2003 相似文献
2.
Two homofermentative strains, Lactobacillus casei NRRL B-441 and Lactobacillus casei subsp. rhamnosus NRRL B-445 were selected for further study from 17 lactic acid bacterial strains screened for lactic acid production. The
effect of temperature on lactic acid production with the selected strains was investigated by adapting both strains to four
different temperatures. The production of L(+)-lactic acid by both strains was most efficient at 37°C, although with L. casei the highest lactic acid concentration was obtained at 41°C. The maximal volumetric productivity with L. casei was 4.1 g l-1 h-1 and with L. casei subsp. rhamnosus 3.5 g l-1 h-1. The composition of the medium was studied in order to replace the costly yeast extract with less expensive sources of nitrogen
and amino acids. From 11 different nitrogen sources investigated at 37°C, barley malt sprouts (88 g l-1 lactic acid in 66 h) and grass extract (74 g l-1 lactic acid in 73 h) were the best economic alternatives. The effect of different combinations of yeast extract, peptone
and malt sprouts was further studied by using statistical experimental design, and an empirical second-order polynomial model
was constructed on the basis of the results. With the right combination most of the yeast extract could be substituted by
barley malt sprouts for efficient lactic acid production. A method for extraction of nutrients and growth factors from malt
sprouts is also described.
Received: 25 September 1995/Accepted: 24 October 1995 相似文献
3.
Boiero L Perrig D Masciarelli O Penna C Cassán F Luna V 《Applied microbiology and biotechnology》2007,74(4):874-880
The aim of this work was to evaluate phytohormone biosynthesis, siderophores production, and phosphate solubilization in three
strains (E109, USDA110, and SEMIA5080) of Bradyrhizobium japonicum, most commonly used for inoculation of soybean and nonlegumes in USA, Canada, and South America. Siderophore production and
phosphate solubilization were evaluated in selective culture conditions, which had negative results. Indole-3-acetic acid
(IAA), gibberellic acid (GA3), and abscisic acid (ABA) production were analyzed by gas chromatography–mass spectrometry (GC-MS). Ethylene and zeatin biosynthesis
were determined by GS–flame ionization detection and high-performance liquid chromatography (HPLC-UV), respectively. IAA,
zeatin, and GA3 were found in all three strains; however, their levels were significantly higher (p < 0.01) in SEMIA5080 (3.8 μg ml−1), USDA110 (2.5 μg ml−1), and E109 (0.87 μg ml−1), respectively. ABA biosynthesis was detected only in USDA110 (0.019 μg ml−1). Ethylene was found in all three strains, with highest production rate (18.1 ng ml−1 h−1) in E109 cultured in yeast extract mannitol medium plus l-methionine. This is the first report of IAA, GA3, zeatin, ethylene, and ABA production by B. japonicum in pure cultures, using quantitative physicochemical methodology. The three strains have differential capability to produce
the five major phytohormones and this fact may have an important technological implication for inoculant formulation. 相似文献
4.
In this study, a characterization of cell wall polysaccharide composition of three yeasts involved in the production of agave
distilled beverages was performed. The three yeast strains were isolated from different media (tequila, mezcal and bakery)
and were evaluated for the β(1,3)-glucanase lytic activity and the β-glucan/mannan ratio during the fermentation of Agave tequilana juice and in YPD media (control). Fermentations were performed in shake flasks with 30 g l−1 sugar concentration of A. tequilana juice and with the control YPD using 30 g l−1 of glucose. The three yeasts strains showed different levels of β-glucan and mannan when they were grown in A. tequilana juice in comparison to the YPD media. The maximum rate of cell wall lyses was 50% lower in fermentations with A. tequilana juice for yeasts isolated from tequila and mezcal than compared to the bakery yeast. 相似文献
5.
Use of virginiamycin to control the growth of lactic acid bacteria during alcohol fermentation 总被引:3,自引:0,他引:3
S H Hynes D M Kjarsgaard K C Thomas W M Ingledew 《Journal of industrial microbiology & biotechnology》1997,18(4):284-291
The antibiotic virginiamycin was investigated for its effects on growth and lactic acid production by seven strains of lactobacilli
during the alcoholic fermentation of wheat mash by yeast. The lowest concentration of virginiamycin tested (0.5 mg Lactrol
TMkg−1 mash), was effective against most of the lactic acid bacteria under study, but Lactobacillus plantarum was not significantly inhibited at this concentration. The use of virginiamycin prevented or reduced potential yield losses
of up to 11% of the produced ethanol due to the growth and metabolism of lactobacilli. However, when the same concentration
of virginiamycin was added to mash not inoculated with yeast, Lactobacillus rhamnosus and L. paracasei grew after an extensive lag of 48 h and L. plantarum grew after a similar lag even in the presence of 2 mg virginiamycin kg−1 mash. Results showed a variation in sensitivity to virginiamycin between the different strains tested and also a possible
reduction in effectiveness of virginiamycin over prolonged incubation in wheat mash, especially in the absence of yeast.
Received 05 August 1996/ Accepted in revised form 18 December 1996 相似文献
6.
Summary New yeast isolates from unexplored Patagonian habitats were studied for the production of biomass and carotenoids as the first
step towards the selection of hyper-producing strains and the design of a process optimization approach. Patagonian yeast
isolates considered as potential biomass and carotenoid sources were studied using ammonium sulphate and urea as nitrogen
sources in semi-synthetic medium (MMS), and agro-industrial byproducts (cane molasses, corn syrup, raw malt extract) as carbon
sources. Maximum pigment production (300 μg g−1) was achieved by Rhodotorula mucilaginosa CRUB 0195 and by novel species Cryptococcus sp. CRUB 1046. β-carotene, torulene and torularhodin were the major carotenoids found. 相似文献
7.
Rocha LL de Aguiar Cordeiro R Cavalcante RM do Nascimento RF Martins SC Santaella ST Melo VM 《Mycopathologia》2007,164(4):183-188
This study investigated the aerobic degradation of phenol by yeast strains isolated from an oil refinery wastewater from the
Northeast of Brazil. The samples displayed low fungal diversity, as only yeast colonies were detected on Sabouraud dextrose
agar containing chloramphenicol 0.05% (w/v). Among the isolates, three yeast strains were selected to be evaluated for their
potential for degrading high phenol concentrations. These species were identified through morphological and biochemical characteristics
as Candida tropicalis, C. rugosa, and Pichia membranaefaciens. Although the strains were able to degrade the phenol concentration present in the wastewater, which was 7 mg l−1, only C. tropicalis was capable of growing at high concentrations of phenol such as 500 mg l−1 and 1,000 mg l−1 in a mineral medium containing this pollutant as the only carbon source. C. rugosa and P. membranaefaciens were inhibited in the presence of 500 mg l−1 of phenol. However, a longer incubation time was needed for C. tropicalis strain to degrade 1,000 mg l−1 of phenol compared to the time required to degrade 500 mg l−1. Moreover, the strain released a significant amount of polysaccharide biosurfactant in the medium probably to minimize the
toxic effect of the high phenol concentration. When challenged with 1,500 and 2,000 mg l−1 of phenol, C. tropicalis was unable to grow at the tested conditions. The results indicate that this strain of C. tropicalis can be considered both a good phenol-degrader and biosurfactant-producer. Application of this strain might be useful in bioremediation
activities or treatment of phenol-polluted wastewater. 相似文献
8.
N. P. Mikhailova E. F. Sorokoletova E. N. Durasova K. A. Vyunov O. I. Shapovalov 《Folia microbiologica》1991,36(2):148-152
Composition of sterol fractions of nystatin-resistantCandida maltosa strains was determined. Using UV-spectrometry, TLC and GLC-MS it was demonstrated that resistance to nystatin is connected
with the composition alterations of yeast cell sterols. Block of different stages of ergosterol biosynthesis was revealed
in some mutants,viz. C-24-transmethylation, Δ8→Δ7, 14α-demethylation, C-5(6)-dehydrogenation, reduction of C-14(15) and C-24(28) double bonds. 相似文献
9.
J G Lewis R P Learmonth P V Attfield K Watson 《Journal of industrial microbiology & biotechnology》1997,18(1):30-36
Fourteen wild-type baking strains of Saccharomyces cerevisiae were grown in batch culture to true stationary phase (exogenous carbon source exhausted) and tested for their trehalose
content and their tolerance to heat (52°C for 4.5 min), ethanol (20% v/v for 30 min), H2O2 (0.3 M for 60 min), rapid freezing (−196°C for 20 min, cooling rate 200°C min−1), slow freezing (−20°C for 24 h, cooling rate 3°C min−1), salt (growth in 1.5 M NaCl agar) or acetic acid (growth in 0.4% w/v acetic acid agar) stresses. Stress tolerance among
the strains was highly variable and up to 1000-fold differences existed between strains for some types of stress. Compared
with previously published reports, all strains were tolerant to H2O2 stress. Correlation analysis of stress tolerance results demonstrated relationships between tolerance to H2O2 and tolerance to all stresses except ethanol. This may imply that oxidative processes are associated with a wide variety
of cellular stresses and also indicate that the general robustness associated with industrial yeast may be a result of their
oxidative stress tolerance. In addition, H2O2 tolerance might be a suitable marker for the general assessment of stress tolerance in yeast strains. Trehalose content
failed to correlate with tolerance to any stress except acetic acid. This may indicate that the contribution of trehalose
to tolerance to other stresses is either small or inconsistent and that trehalose may not be used as a general predictor
of stress tolerance in true stationary phase yeast.
Received 10 October 1995/ Accepted in revised form 10 September 1996 相似文献
10.
Carvalho RS Gomes LH Gonzaga do P Filho L Tavares FC 《Applied microbiology and biotechnology》2008,77(5):1131-1137
Saccharomyces cerevisiae hexokinase-less strains were produced to study the production of ethanol and fructose from sucrose. These strains do not
have the hexokinases A and B. Twenty-three double-mutant strains were produced, and then, three were selected for presenting
a smaller growth in yeast extract–peptone–fructose. In fermentations with a medium containing sucrose (180.3 g L−1) and with cell recycles, simulating industrial conditions, the capacity of these mutant yeasts in inverting sucrose and fermenting
only glucose was well characterized. Besides that, we could also see their great tolerance to the stresses of fermentative
recycles, where fructose production (until 90 g L−1) and ethanol production (until 42.3 g L−1) occurred in cycles of 12 h, in which hexokinase-less yeasts performed high growth (51.2% of wet biomass) and viability rates
(77% of viable cells) after nine consecutive cycles. 相似文献
11.
Acetaldehyde is relevant for wine aroma, wine color, and microbiological stability. Yeast are known to play a crucial role
in production and utilization of acetaldehyde during fermentations but comparative quantitative data are scarce. This research
evaluated the acetaldehyde metabolism of 26 yeast strains, including commercial Saccharomyces and non-Saccharomyces, in a reproducible resting cell model system. Acetaldehyde kinetics and peak values were highly genus, species, and strain
dependent. Peak acetaldehyde values varied from 2.2 to 189.4 mg l−1 and correlated well (r
2 = 0.92) with the acetaldehyde production yield coefficients that ranged from 0.4 to 42 mg acetaldehyde per g of glucose in
absence of SO2. S. pombe showed the highest acetaldehyde production yield coefficients and peak values. All other non-Saccharomyces species produced significantly less acetaldehyde than the S. cerevisiae strains and were less affected by SO2 additions. All yeast strains could degrade acetaldehyde as sole substrate, but the acetaldehyde degradation rates did not
correlate with acetaldehyde peak values or acetaldehyde production yield coefficients in incubations with glucose as sole
substrate. 相似文献
12.
Physiological samples of 100 piglets fed diets containing 0.01, 0.06, 0.15, 0.22 and 0.42 mg ZON and 0.2, 0.8, 1.0, 1.9 and
3.9 mg DON per kg over a period of 35±1.5 days were investigated for concentrations of deoxynivalenol (DON) and zearalenone
(ZON) and their metabolites.
DON was detected in serum, bile and urine in increasing concentrations corresponding to the diet contamination. The metabolite
de-epoxy-DON was detected only in urine. The DON contamination of the diet was closely reflected by the serum concentrations
of the piglets.
ZON and its metabolite α-zearalenol were detected in bile fluid, liver and urine, while β-zearalenol was only detected in
bile fluid. In serum neither ZON nor its metabolites were found. The total concentration of ZON plus its metabolites in the
bile fluid corresponded well with the dietary contamination.
For all analyses it has to be noted that toxin residues were detectable even in individual samples of piglets fed the control
diet containing 0.01 mg ZON/kg and 0.2 mg DON/kg.
Presented at the 25th Mykotoxin Workshop in Giessen, Germany, May 19–21, 2003 相似文献
13.
Synthesis of optically active ethyl 4-chloro-3-hydroxybutanoate by microbial reduction 总被引:15,自引:0,他引:15
Y. Yasohara N. Kizaki J. Hasegawa S. Takahashi M. Wada M. Kataoka S. Shimizu 《Applied microbiology and biotechnology》1999,51(6):847-851
A total of 400 yeast strains were examined for the ability to reduce ethyl 4-chloroacetoacetate (COBE) to ethyl 4-chloro-3-hydroxybutyrate
(CHBE) by using acetone-dried cells in the presence of a coenzyme-recycling system in water/n-butyl acetate. We discovered some yeast strains that reduced COBE to (S)-CHBE. Heating of acetone-dried cells of the selected yeast strains increased the optical purity of the product. There may
be several enzymes that can reduce COBE stereoselectively in the same yeast cells. The cultured broth of Candida magnoliae accumulated 90 g/l (S)-CHBE (96.6% enantiomeric excess, e.e.) in the presence of glucose, NADP and glucose dehydrogenase in n-butyl acetate. When these cells were heated, the stereoselectivity of the reduction increased to 99% e.e. (S)-CHBE is one of the useful chiral building blocks applicable to the synthesis of some pharmaceuticals. We expect that the
cheap and industrial production of this important chiral compound will follow the discovery of this yeast strain.
Received: 9 September 1998 / Received last revision: 17 February 1999 / Accepted: 5 March 1999 相似文献
14.
S. U. ?str?m M. E. Nordlund F. L. Erickson E. M. Hannig A. S. Bystr?m 《Molecular & general genetics : MGG》1999,261(6):967-976
The Saccharomyces cerevisiae gene RIT1 encodes a phospho-ribosyl transferase that exclusively modifies the initiator tRNA (tRNAMet
i) by the addition of a 2′-O-ribosyl phosphate group to Adenosine 64. As a result, tRNAMet
i is prevented from participating in the elongation steps of protein synthesis. We previously showed that the modification
is not essential for the function of tRNAMet
i in the initiation of translation, since rit1 null strains are viable and show no obvious growth defects. Here, we demonstrate that yeast strains in which a rit1 null allele is combined with mutations in any of the genes for the three subunits of eukaryotic initiation factor-2 (eIF-2),
or with disruption alleles of two of the four initiator methionine tRNA (IMT) genes, show synergistic growth defects. A multicopy plasmid carrying an IMT gene can alleviate these defects. On the other hand, introduction of a high-copy-number plasmid carrying the TEF2 gene, which encodes the eukaryotic elongation factor 1α (eEF-1α), into rit1 null strains with two intact IMT genes had the opposite effect, indicating that increased levels of eEF-1α are deleterious to these strains, presumably due
to sequestration of the unmodified met-tRNAMet
i for elongation. Thus, under conditions in which the components of the ternary met-tRNAMet
i:GTP:eIF-2 complex become limiting or are functionally impaired, the presence of the 2′-O-ribosyl phosphate modification in
tRNAMet
i is important for the provision of adequate amounts of tRNAMet
i for formation of this ternary complex.
Received: 20 November 1998 / Accepted: 7 April 1999 相似文献
15.
Effects of acetic acid and lactic acid on the growth of Saccharomyces cerevisiae in a minimal medium 总被引:1,自引:0,他引:1
N V Narendranath K C Thomas W M Ingledew 《Journal of industrial microbiology & biotechnology》2001,26(3):171-177
Specific growth rates (μ) of two strains of Saccharomyces cerevisiae decreased exponentially (R
2>0.9) as the concentrations of acetic acid or lactic acid were increased in minimal media at 30°C. Moreover, the length of
the lag phase of each growth curve (h) increased exponentially as increasing concentrations of acetic or lactic acid were
added to the media. The minimum inhibitory concentration (MIC) of acetic acid for yeast growth was 0.6% w/v (100 mM) and that
of lactic acid was 2.5% w/v (278 mM) for both strains of yeast. However, acetic acid at concentrations as low as 0.05–0.1%
w/v and lactic acid at concentrations of 0.2–0.8% w/v begin to stress the yeasts as seen by reduced growth rates and decreased
rates of glucose consumption and ethanol production as the concentration of acetic or lactic acid in the media was raised.
In the presence of increasing acetic acid, all the glucose in the medium was eventually consumed even though the rates of
consumption differed. However, this was not observed in the presence of increasing lactic acid where glucose consumption was
extremely protracted even at a concentration of 0.6% w/v (66 mM). A response surface central composite design was used to
evaluate the interaction between acetic and lactic acids on the specific growth rate of both yeast strains at 30C. The data
were analysed using the General Linear Models (GLM) procedure. From the analysis, the interaction between acetic acid and
lactic acid was statistically significant (P≤0.001), i.e., the inhibitory effect of the two acids present together in a medium is highly synergistic. Journal of Industrial Microbiology & Biotechnology (2001) 26, 171–177.
Received 06 June 2000/ Accepted in revised form 21 September 2000 相似文献
16.
Domínguez-Bocanegra AR Ponce-Noyola T Torres-Muñoz JA 《Applied microbiology and biotechnology》2007,75(4):783-791
Phaffia rhodozyma (now Xanthophyllomyces dendrorhous) and Haematococcus pluvialis are known as the major prominent microorganisms able to synthesize astaxanthin natural pigment. Important research efforts
have been made to determine optimal conditions for astaxanthin synthesis. When the focus is on astaxanthin production, the
maximal reported value of 9.2 mg/g cell is obtained within H. pluvialis grown on BAR medium, under continuous illumination (345 μmol photon m−2 s−1) and without aeration. Whereas fermentation by mutated R1 yeast grown on coconut milk produced 1,850 μg/g yeast. However,
when looking at astaxanthin productivity, the picture is slightly different. The figures obtained with P. rhodozyma are rather similar to those of H. pluvialis. Maximal reported values are 170 μg/g yeast per day with a wild yeast strain and 370 μg/g yeast per day with mutated R1 yeast.
In the case of H. pluvialis, maximal values ranged from 290 to 428 μg/g cell per day depending on the media (BG-11 or BAR), light intensity (177 μmol
photon m−2 s−1), aeration, etc. The main aim of this work was to examine how astaxanthin synthesis, by P. rhodozyma and H. pluvialis, could be compared. The study is based on previous works by the authors where pigment productions have been reported. 相似文献
17.
Tomotake Morita Masako Takashima Tokuma Fukuoka Masaaki Konishi Tomohiro Imura Dai Kitamoto 《Applied microbiology and biotechnology》2010,88(3):679-688
The producers of glycolipid biosurfactant, mannosylerythritol lipid-B (MEL-B), were isolated from leaves of Perilla frutescens on Ibaraki in Japan. Four isolates, 1D9, 1D10, 1D11, and 1E5, were identified as basidiomycetous yeast Pseudozyma tsukubaensis by rDNA sequence and biochemical properties. The structure of MEL-B produced by these strains was analyzed by 1H nuclear magnetic resonance and gas chromatography–mass spectrometry methods, and was determined to be the same as the diastereomer
MEL-B produced by P. tsukubaensis NBRC 1940. Of these isolates, P. tsukubaensis 1E5 (JCM 16987) is capable of producing the largest amount of the diastereomer MEL-B from vegetable oils. In order to progress
the diastereomer MEL-B production by strain 1E5, factors affecting the production, such as carbon and organic nutrient sources,
were further examined. Olive oil and yeast extract were the best carbon and nutrient sources, respectively. Under the optimal
conditions, a maximum yield, productivity, and yield coefficient of 73.1 g/L, 10.4 g L−1 day−1, and 43.5 g/g were achieved by feeding of olive oil in a 5-L jar-fermenter culture using strain 1E5. 相似文献
18.
In the wild type strain (stock no. 1227) of Thermoactinomyces vulgaris, as reported earlier [Sinha and Singh (1980) Biochem. J. 190, 457–460], all phosphatase isoenzymes (three alkaline — AlpI,
AlpII and AlpIII, and one acidic — Acp) are present. However, the auxotrophic mutants, the strains 1286 (thi
−), 1279 (nic
−, ura
−) and 1278 (thi
−, ura
−) exhibited two alkaline phosphatase isoenzymes (AlpII and AlpIII), but AlpI was lacking. In the strain 1261 (nic
−, thi
−), only AlpIII was expressed, and AlpI and AlpII isoenzymes were missing. The results suggest that the strains, which require
either thiamine (1286 and 1278) or nicotinamide (1279) for their growth, were AlpI
− mutants; and the strain (1261), which requires both thiamine and nicotinamide for its growth, was AlpI
−/AlpII
− double mutant. There was no direct correlation between uracil auxotrophy and the expression of phosphatases. The uniform
expression of AlpIII and Acp in all the strains, irrespective of their nutrient requirements, suggest that these constitutive
phosphatases are species-specific. The specific activities of the thermophilic acid and alkaline phosphatases were maximum
in the wild type strain (1227) of T. vulgaris. The next in phosphatase activity was the strain 1279 (an AlpI
− mutant), followed by their decrease, in order, in the strains 1286 and 1278 (which were also AlpI
− mutants); while least activity of these enzymes was observed in the obligate thermophile strain 1261 (AlpI
−/AlpII
− double mutant). 相似文献
19.
Eicosapentaenoic and docosahexaenoic acids production by and okara-utilizing potential of thraustochytrids 总被引:3,自引:0,他引:3
K W Fan F Chen E BG Jones L LP Vrijmoed 《Journal of industrial microbiology & biotechnology》2001,27(4):199-202
Nine thraustochytrid strains isolated from subtropical mangroves were screened for their eicosapentaenoic acid (EPA) and docosahexaenoic
acid (DHA) production potential in a glucose yeast extract medium. Their ability to utilize okara (soymilk residue) for growth
and EPA and DHA production was also evaluated. EPA yield was low in most strains, while DHA level was high on glucose yeast
extract medium, producing 28.1–41.1% of total fatty acids, for all strains, with the exception of Ulkenia sp. KF13. The DHA yield of Schizochytrium mangrovei strains ranged from 747.7 to 2778.9 mg/l after 52 h of fermentation at 25°C. All strains utilized okara as a substrate for
growth, but DHA yield was lower when compared with fermentation in a glucose yeast extract medium. Journal of Industrial Microbiology & Biotechnology (2001) 27, 199–202.
Received 11 December 2000/ Accepted in revised form 29 June 2001 相似文献
20.
Zhu Daling Li Aihua Wang Jianguo Li Ming Cai Taozhen Hu Jing 《Frontiers of Biology in China》2007,2(2):176-179
Nine strains of Aeromonas hydrophila isolated from diseased fish or soft-shelled tortoise were tested for the presence of three virulence genes including the
genes encoding aerolysin, hemolysin, and extracellular serine protease (i.e., aerA, hlyA, and ahpA, respectively). These genes were investigated using polymerase chain reaction (PCR) with specific primers for each gene.
And the pathogenicities to Carrassius auratus ibebio of these strains were also assayed. PCR results demonstrated that the distribution patterns of aerA, hlyA, and ahpA were different in these strains. 6/9 of A. hydrophila strains were aerA positive, 8/9 of strains hlyA positive, 7/9 of strains ahpA positive, respectively. However, the assay for pathogenesis showed that two strains (A. hydrophila XS91-4-1 and C2) were strong virulent, two strains (A. hydrophila ST78-3-3 and 58-20-9) avirulent and the rest middle virulent was to the fish. In conclusion, there are significant correlation
between the distribution pattern of the three virulence genes and the pathogenicity to Carrassius auratus ibebio. All strong virulent A. hydrophila strains were aerA
+
hlyA
+
ahpA
+ genotype, and all aerA
+
hlyA
+
ahpA
+ strains were virulent. Strains with the genotype of aerA
−
hlyA
−
ahpA
+ have middle pathogenicity. In the present study, we found for the first time that all A. hydrophila isolated from the ahpA positive were virulent to Carrassius auratus ibebio. Additionally, there was a positive correlation between the virulence of A. hydrophila and the presence of aerA and ahpA.
__________
Translated from Acta Scientiarum Naturalium Universitatis Sunyatseni, 2006, 45(1): 82–85 [译自: 中山大学学报 (自然科学版)] 相似文献