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1.
Gioconda San-Blas Françoise Sorais Gustavo Niño-Vega Cioly Méndez Felipe San-Blas 《Current microbiology》1998,37(2):141-143
Cytosolic proteinases were assayed in both morphological phases of Paracoccidioides brasiliensis. Preparations from the mycelial phase were more active in vitro than those from the yeast cells. Optimal proteinase activities
for both phases occurred at pH's between 6.0 and 9.0, and at 45°C. Gelatin-SDS-PAGE electrophoresis separated several bands
(58–112 kDa) in mycelial preparations; a single band (70 kDa) was seen in yeast preparations. Enzymatic activities were inhibited
by antipain, phenyl methyl sulfonyl fluoride (PMSF), and chymostatin, suggestive of serine proteinases. Partial inhibition
of the mycelial enzymes by ethylene diamine tetraacetic acid (EDTA), 1,10-phenanthroline, and iodoacetamide, also suggested
the presence of cysteine- and metallo-proteinases. The enzymatic activity increased in preparations extracted from yeast cells
transforming to mycelia, and decreased in preparations obtained from the reverse process.
Received: 29 September 1997 / Accepted: 19 February 1998 相似文献
2.
Gioconda San-Blas Felipe San-Blas Françoise Sorais Belisario Moreno José Ruiz-Herrera 《Archives of microbiology》1996,166(6):411-413
Putrescine and spermidine were the only polyamines found inParacoccidioides brasiliensis, a dimorphic fungus pathogenic for humans. Free polyamines (putrescine>spermidine) increased during the first 24 h of yeast growth, with a second peak at 42 h, and also during the first 12 h of mycelium-to-yeast transition (spermidine>putrescine). Conjugated and bound polyamines were also quantified. 1,4-Diamino-2-butanone decreased free putrescine and spermidine accumulation by inhibiting the activity of ornithine decarboxylase. The increase in free polyamines corresponds to bud emergence in yeast growth and to the mycelium-to-yeast transition ofP. brasiliensis.Abbreviations
DAB
1,4-Diamino-2-butanone
-
Y
Yeasts
-
M
Mycelia
-
ODC
Ornithine decarboxylase 相似文献
3.
Ayako Sano Reiko Tanaka Kazuko Nishimura Cilmery S. Kurokawa Kunie labuki R. Coelho Marcello Franco Mario Rubens Montenegro Makoto Miyaji 《Mycoscience》1997,38(2):117-122
We have studied the physiological and morphological features of 17 isolates ofParacoccidioides brasiliensis in order to define their phenotypes. The isolates were cultured at room temperature on potato dextrose agar (PDA, Difco)
slants for mycelial growth and in 1% dextrose brain heart infusion agar (BHIA, Difco) at 37°C for the study of yeast forms.
Most mycelial and yeast forms grew well between pH 5.6–9.4. In their response to osmotic pressure the isolates were separated
in three groups: intolerant, intermediate and tolerant. They also varied in carbohydrate assimilation tests, which indicated
important metabolic variation. No clear differences were observed in phenol oxidase tests, KNO3, starch, casein and arbutin assimilation tests. Only 1 of the isolates, Bt-19, had gelatinase activity. No correlation was
observed between the above differences and virulence. Two patterns of growth were observed in the mycelial cultures, glabrous
and cottonous, the latter being correlated with increased virulence for ddY mice. Most yeast forms grew as cerebriform colonies,
but Pb-HC and Bt-19 colonies had a cobblestone-like surface. 相似文献
4.
The gram-negative bacterium Myxobacter sp. AL-1 produces chitosanase-cellulase activity that is maximally excreted during the stationary phase of growth. Carboxymethylcellulase
zymogram analysis revealed that the enzymatic activity was correlated with two bands of 32 and 35 kDa. Ion-exchange-chromatography-enriched
preparations of the 32-kDa enzyme were capable of degrading the cellulose fluorescent derivatives 4-methylumbelliferyl-β-d-cellobioside and 4-methylumbelliferyl-β-d-cellotrioside. These enzymatic preparations also showed a greater capacity at 70° C than at 42° C to degrade chitosan oligomers
of a minimum size of six units. Conversely, the β-1,4 glucanolytic activity was more efficient at attacking carboxymethylcellulose
and methylumbelliferyl-cellotrioside at 42° C than at 70° C. The 32-kDa enzyme was purified more than 800-fold to apparent
homogeneity by a combination of ion-exchange and molecular-exclusion chromatography. Amino-terminal sequencing indicated that
mature chitosanase-cellulase shares more than 70% identity with endocellulases produced by strains DLG, PAP115, and 168 of
the gram-positive microorganism Bacillus subtilis.
Received: 6 January 1997 / Accepted: 29 May 1997 相似文献
5.
A dextranase (EC 3.2.1.11) was purified and characterized from the IP-29 strain of Sporothrix schenckii, a dimorphic pathogenic fungus. Growing cells secreted the enzyme into a standard culture medium (20 °C) that supports the
mycelial phase. Soluble bacterial dextrans substituted for glucose as substrate with a small decrease in cellular yield but
a tenfold increase in the production of dextranase. This enzyme is a monomeric protein with a molecular mass of 79 kDa, a
pH optimum of 5.0, and an action pattern against a soluble 170-kDa bacterial dextran that leads to a final mixture of glucose
(38%), isomaltose (38%), and branched oligosaccharides (24%). In the presence of 200 mM sodium acetate buffer (pH 5.0), the
K
m for soluble dextran was 0.067 ± 0.003% (w/v). Salts of Hg2+, (UO2)2+, Pb2+, Cu2+, and Zn2+ inhibited by affecting both V
max and K
m. The enzyme was most stable between pH values of 4.50 and 4.75, where the half-life at 55 °C was 18 min and the energy of
activation for heat denaturation was 99 kcal/mol. S. schenckii dextranase catalyzed the degradation of cross-linked dextran chains in Sephadex G-50 to G-200, and the latter was a good
substrate for cell growth at 20 °C. Highly cross-linked grades (i.e., G-10 and G-25) were refractory to hydrolysis. Most strains
of S. schenckii from Europe and North America tested positive for dextranase when grown at 20 °C. All of these isolates grew on glucose at
35 °C, a condition that is typically associated with the yeast phase, but they did not express dextranase and were incapable
of using dextran as a carbon source at the higher temperature.
Received: 29 December 1997 / Accepted: 4 March 1998 相似文献
6.
F. Canganella J. M. Gonzalez Miki Yanagibayashi C. Kato Koki Horikoshi 《Archives of microbiology》1997,168(1):1-7
We studied the effects of high temperatures and elevated hydrostatic pressures on the physiological behavior and viability
of the extremely thermophilic deep-sea archaeon Thermococcus peptonophilus. Maximal growth rates were observed at 30 and 45 MPa although no significant increases in cell yields were detected. Growth
at 60 MPa was slower. The optimal growth temperature shifted from 85° C at 30 MPa to 90–95° C at 45 MPa. Cell viability during
the stationary phase was also enhanced under high pressure. A trend towards barophily at pressures greater than those encountered
in situ at the sea floor was demonstrated at increasing growth temperatures. The viability of cells during starvation, at
high temperature (90, 95° C), and at low temperature (10° C) was enhanced at 30 and 45 MPa as compared to atmospheric pressure.
These results show that the extremely thermophilic archaeon T. peptonophilus is a barophile.
Received: 21 October 1996 / Accepted: 5 February 1997 相似文献
7.
Differential profiles of soluble proteins during the initiation of morphogenesis in Candida albicans 总被引:1,自引:0,他引:1
Candida albicans is a dimorphic fungus that can grow either as yeast or as mycelia. The mycelial form may be required for tissue penetration
and therefore may have a role in pathogenesis. The protein profiles of the cell-free S100 fraction from budding yeast cells
and germ tube-forming cells (an early stage of the transition between yeast and mycelia) were evaluated using two-dimensional
polyacrylamide gel electrophoresis (2-D PAGE). Yeast growth or germ tube formation was induced in carbon-starved cells at
37° C by either glucose, galactose or N-acetylglucosamine at pH 4.5 or pH 6.7. More than 400 constitutively synthesised polypeptides were identified on 2-D PAGE
by silver staining. A few polypeptides which seem to reflect the release from carbon starvation were detected, but no polypeptides
unique to either morphology were observed. Fractionation of S100 preparations by polyethylenimine or heparin-agarose affinity
chromatography, which have been used to detect DNA-binding proteins, revealed several proteins that were synthesised on the
resumption of cell growth or in response to pH difference. Heparin-agarose also bound novel polypeptides in the size range
130–200 kDa that were preferentially synthesised in germ tube-forming cells. These results suggest that any protein factors
that might exert a regulatory role early in germ tube formation are of low abundance, and that a minor group of soluble proteins
involved in C. albicans morphogenesis may be differentially synthesised.
Received: 11 March 1996 / Accepted: 10 July 1996 相似文献
8.
N. Barron R. Marchant L. McHale A. P. McHale 《Applied microbiology and biotechnology》1995,43(3):518-520
The thermotolerant yeast strain, Kluyveromyces marxianus IMB3, was found to be capable of ethanol production during growth at 45°C on media containing milled paper and exogenously
added commercial cellulase. At maximum achievable cellulose concentrations in shake-flask cultures, ethanol production increased
to 6.6 g/l at 45°C, representing an overall level of conversion of 21% of the maximum theoretical yield. Subsequent studies
involving variations in added cellulase concentrations to the batch systems demonstrated that ethanol yields could be increased
to 10 g/l at 45°C, which represented 39% of the maximum theoretical yield. As a result of ethanol production at 45°C in the
systems examined, we suggest that the thermotolerant ethanol-producing yeast strain K. marxianus represents a novel candidate for use in simultaneous saccharification and conversion of the resulting substrates to ethanol.
Received: 9 June 1994/Received revision: 8 August 1994/Accepted: 12 August 1994 相似文献
9.
The coloration of cells of the cyanobacterium Synechococcus sp. PCC 7002 changed from normal blue-green to yellow-green when cells were grown at 15° C in a medium containing nitrate
as the sole nitrogen source. This change of coloration was similar to a general response to nutrient deprivation (chlorosis).
For the chlorotic cells at 15° C, the total amounts of phycobiliproteins and chlorophyll a decreased, high levels of glycogen accumulated, and growth was arithmetic rather than exponential. These changes in composition
and growth occurred in cells grown at low (50 μE m–2 s–1) as well as high (250 μE m–2 s–1) light intensity. After a temperature shift-up to 38° C, chlorotic cells rapidly regained their normal blue-green coloration
and normal exponential growth rate within 7 h. When cells were grown at 15° C in a medium containing urea as the reduced nitrogen
source, cells grew exponentially and the symptoms of chlorosis were not observed. The decrease in photosynthetic oxygen evolution
activity at low temperature was much smaller than the decrease in growth rate for cells grown on nitrate as the nitrogen source.
These studies demonstrate that low-temperature-induced chlorosis of Synechococcus sp. PCC 7002 is caused by nitrogen limitation and is not the result of limited photosynthetic activity or photodamage to
the photosynthetic apparatus, and that nitrogen assimilation is an important aspect of the low-temperature physiology of cyanobacteria.
Received: 24 April 1997 / Accepted: 5 August 1997 相似文献
10.
The effects of the putrescine analogue 1-aminooxy-3-aminopropane on fungal polyamine metabolism were evaluated using Sclerotinia sclerotiorum as an experimental model. The compound inhibited ornithine decarboxylase, spermidine synthase, and S -adenosyl-methionine decarboxylase in mycelial extracts. Addition of 1-aminooxy-3-aminopropane at 1 mM to the culture medium did not reduce mycelial growth and caused a 29% decrease in free spermidine and a two-fold increase in free spermine. When added 4.5 h before the determination of ornithine decarboxylase, 1-aminooxy-3-aminopropane reduced in vivo activity of this enzyme by 40–50%. When added 48 h before the determination, 1-aminooxy-3-aminopropane at 0.01 and 0.1 mM caused a slight increase of in vivo ornithine decarboxylase activity, while it had no effect at 1 mM. Comparison of the action of 1-aminooxy-3-aminopropane with that of other inhibitors of polyamine biosynthesis suggested that its effects on in vivo ornithine decarboxylase activity resulted from a balance between direct inhibition of enzyme activity and indirect stimulation of enzyme synthesis and/or activity mediated by the decrease in spermidine levels, which in turn was due to inhibition of spermidine synthase and S
-adenosyl-methionine decarboxylase. The potential of 1-aminooxy-3-aminopropane as a tool for studies on fungal polyamine metabolism and for the control of plant diseases of fungal origin is discussed.Abbreviations AdoMetDC
S-Adenosyl-methionine decarboxylase
- DFMO
-Difluoromethylornithine
- MGBG
Methylglyoxal
bis-[guanyl hydrazone]
- ODC
Ornithine decarboxylase 相似文献
11.
The expression of the Arabidopsis heat-shock protein (HSP) 18.2 promoter β-d-glucuronidase (GUS) chimera gene was studied in various organs of the transgenic Nicotiana plumbaginifolia during the recovery phase at normal temperatures (20–22 °C) following heat-shock (HS) treatment. The optimum HS temperature
for GUS activity in the anthers, petals and capsules was 42 °C, but in immature seeds and the placentas of capsules it was
36 °C and 39 °C, respectively. No apparent GUS activity was observed in any organs except for dry seeds after HS at 45 °C,
although the activity in dry seeds was apparent even after HS at 48 °C. After HS at 42 °C, GUS activity in the flower tissues
was the highest before anthesis and declined thereafter.
Received: 13 January 1998 / Revision received: 25 January 1999 / Accepted: 3 March 1999 相似文献
12.
The culturability of a strictly anaerobic, extremely thermophilic archaeon, Thermococcus peptonophilus (optimal growth temperature: 85° C), was studied during survival stages at various temperatures (98, 85, 70, and 4° C).
Total cell number (determined by DAPI staining), active cells (rhodamine-stained cells), and culturable cells (using most-probable-number)
were counted over time. The number of culturable cells decreased under each condition tested. The total number of cells significantly
decreased only at temperatures close to the maximum for growth (98° C); at this temperature, the cells spontaneously lysed.
Our results suggested that survival at 4° C in oxygenated waters might be a mechanism for the dispersion of extreme thermophiles
in the ocean. In addition, we proved the existence of T. peptonophilus cells in several physiological states: culturable cells, active non-culturable cells, inactive non-culturable cells, and
dead cells. Cell death was caused by cellular lysis.
Received: 5 February 1996 / Accepted: 16 April 1996 相似文献
13.
A number of substrates were tested for the cultivation of microorganisms to produce a host of enzymes. The effect of different
substrates (wheat and rice straw, sugar cane waste, wood waste), incubation temperatures (20–40°C), initial pH levels (3.5–9.0),
incubation periods (0–72 hours) and nitrogen sources (ammonium sulfate, urea, peptone, yeast extract, sodium nitrate) on growth
and α-amylase activity was studied for the native and mutant strains. Maximum enzyme activity was observed at 1.5% wheat straw
for Aspergillus niger FCBP-198 and An-Ch-4.7 and at 2% wheat straw for An-UV-5.6, with sodium nitrate as a principle nitrogen source. The optimum
temperature for maximum enzyme activity was 30°C for the parental strain, while An-UV-5.6 and An-Ch-4.7 thrived well at 32.5°C.
The best conditions of pH and incubation duration were 4.5 and 48 hours, respectively, for all the strains. Mass production
under preoptimized growth conditions demonstrated the suitability of wheat straw for swift mycelial colonization and viability. 相似文献
14.
The expression of the Arabidopsis heat shock protein (HSP) 18.2 promoter-β-d-glucuronidase (GUS) chimera gene was investigated in transgenic Nicotiana plumbaginifolia plants during the recovery phase at normal temperatures (20–22 °C) after a heat shock (HS) treatment. GUS activity increased
during the recovery phase after HS at 42 °C for 2 h, and maximal GUS activity was observed after 12 h at normal temperatures,
at levels 50–100 times higher than the activity immediately after HS. After HS at 44 °C, little GUS activity was observed
during the first 20–24 h at normal temperatures, but the activity increased gradually thereafter, to reach a maximum at 40–50 h.
After HS at 45 °C, no GUS activity was observed throughout the experimental period. RT-PCR analysis showed that GUS mRNA
remained for 10 h after a 2-h HS at 42 °C and for 40 h after a 2-h HS at 44 °C. These findings demonstrate that brief HS
treatment, especially at a sublethal temperature, induces a long-term accumulation of HSP-GUS mRNA during the recovery phase.
Received: 31 July 1998 / Revision received: 4 November 1998 / Accepted: 19 February 1999 相似文献
15.
Palmero Llamas D de Cara Gonzalez M Iglesias Gonzalez C Ruíz Lopez G Tello Marquina JC 《Journal of industrial microbiology & biotechnology》2008,35(11):1405-1409
The mycelial growth of 18 Fusarium solani strains isolated from sea beds of the south-eastern coast of Spain was tested on potato-dextrose-agar adjusted to different
osmotic potentials with either KCl or NaCl (−1.50 to −144.54 bars) in 10 °C intervals ranging from 15 to 35 °C. Fungal growth
was determined by measuring colony diameter after 4 days of incubation. Mycelial growth was maximal at 25 °C. The quantity
and frequency pattern of mycelial growth of F. solani differ significantly at 15 and 25 °C, with maximal growth occurring at the highest water potential tested (−1.50 bars); and
at 35 °C, with a maximal mycelial growth at −13.79 bars. The effect of water potential was independent of salt composition.
The general growth pattern of F. solani showed declining growth at potentials below −41.79 bars. Fungal growth at 35 °C was always higher than that grow at 15 °C,
of all the water potentials tested. Significant differences observed in the response of mycelia to water potential and temperature
as main and interactive effects. The viability of cultures was increasingly inhibited as the water potential dropped, but
some growth was still observed at −99.56 bars. These findings could indicate that marine strains of F. solani have a physiological mechanism that permits survival in environments with low water potential. The observed differences in
viability and the magnitude of growth could indicate that the biological factors governing potential and actual growth are
affected by osmotic potential in different ways. 相似文献
16.
N. Schmitz 《Molecular & general genetics : MGG》1999,261(4-5):716-724
The protein kinase p34cdc2 is required at the onset of DNA replication and for entry into mitosis. The catalytic subunit and its regulatory proteins,
notably the cyclins, are conserved from yeast to man. This suggests that the control mechanisms necessary for progression
through the cell cycle in fission yeast are conserved throughout evolution. This work describes the characterization of a
fission yeast strain that is dependent for cell cycle progression on the activity of the p34CDC2 protein kinase from chicken. The response of the chicken p34CDC2 protein kinase to cell cycle components of fission yeast was examined. Cells expressing the chicken p34CDC2 protein divide at reduced size at 31° C. Cells are temperature sensitive at 35.5° C and die as a result of mitotic catastrophe.
This phenotype can be rescued by delaying cell cycle progression at the G1-S transition by adding low concentrations of hydroxyurea.
Schizosaccharomyces pombe cells that are dependent on chicken p34CDC2 are cold sensitive. At 19° C to 25° C cells arrest in the G1 phase, while traversal of the G2-M transition is not blocked
at low temperature. Expression of chicken p34CDC2 in the cold-sensitive G2-M mutant cdc2A21 suppresses the G1 arrest.
Received: 14 October 1998 / Accepted: 15 March 1999 相似文献
17.
A Kademi L Fakhreddine N Aït-Abdelkader J C Baratti 《Journal of industrial microbiology & biotechnology》1999,23(3):188-193
Growth and esterase production (activity on p-nitrophenyl caprylate) by the newly isolated Bacillus circulans MAS2 bacterial strain were studied. The growth rate at 50°C was high (0.9 h-1) on LB medium with glucose added. Esterase production followed growth with the majority of activity being intracellular during
exponential growth phase. During stationary phase, the esterase activity was released in the culture medium. The strain was
able to grow at 35– 55°C with maximum growth rate at 50°C, showing a pattern typical of a moderate thermophile. Growth occurred
at pH 6–9 with a maximum at 8, with a similar pattern for the esterase production. Addition of glucose, fructose, sucrose
or sodium acetate greatly promoted both growth and esterase production while starch, inulin, tributyrin or glycerol showed
no effect. Complex nitrogen sources such as tryptone or yeast extract increased growth and esterase production while mineral
sources (ammonium chloride or sulfate), glycine or glutamate showed no effect. An increase of tryptone plus yeast extract
and glucose concentrations stimulated growth and esterase production which reached 160 U L−1.
Received 17 March 1999/ Accepted in revised form 25 June 1999 相似文献
18.
M Guilloux-Benatier O Pageault A Man M Feuillat 《Journal of industrial microbiology & biotechnology》2000,25(4):193-197
Oenococcus oeni exhibited extracellular β (1→3) glucanase activity. This activity increased when cells were cultivated with glycosidic cell-wall
macromolecules. In addition, the culture supernatant of the organism effectively lysed viable or dead cells of Saccharomyces cerevisiae. This lytic activity appeared in the early stationary phase of bacterial growth. Yeast cells at the end of the log phase
of growth were the most sensitive. The optimum temperature for lysis of viable yeast cells was 40°C, which is very different
from the temperatures observed in enological conditions (15–20°C). Moreover, the rate of the lytic activity was significantly
lower in comparison with yeast cell wall-degrading activities previously measured in various other microorganisms. Therefore,
yeast cell death that is sometimes observed during the alcoholic fermentation could hardly be attributed to the lytic activity
of O. oeni. Journal of Industrial Microbiology & Biotechnology (2000) 25, 193–197.
Received 27 December 1999/ Accepted in revised form 14 July 2000 相似文献
19.
A. S. Devakumar P. Gawai Prakash M. B. M. Sathik James Jacob 《Trees - Structure and Function》1999,13(3):161-167
In this study a comparison of the canopy architecture and the growth and distribution of roots was made in 10-year-old trees
of Hevea brasiliensis grown in a severely drought-prone area on the west coast of India under rainfed and irrigated conditions. LAI and light interception
increased significantly in the irrigated compared to the rainfed trees. Girth and height of the tree were 29 and 19% more
while width and height of the canopy were 19 and 20% more in the irrigated than rainfed trees. There were 22% more primary
branches which had 26% more diameter in the irrigated trees than rainfed trees. The branches were inserted on the main trunk
at an angle of 58.36° in the irrigated and 44.22° in rainfed trees. The above changes led to more light penetration which
altered the light distribution inside the rainfed trees during summer and inhibited leaf photosynthesis particularly in the
top canopy leaves. In the rainfed trees most of the growth occurred during the short favorable season immediately after the
monsoon between June and October and no growth or even shrinking of the trunk was seen during summer. In the irrigated trees
a higher growth was seen throughout the year and summer had no adverse effect. Although there was some difference in the root
distribution pattern, the total root density per unit soil volume did not vary between the irrigated and rainfed trees.
Key words Hevea brasiliensis· Drought · Crown architecture · Micro-climate · Root growth
Received: 8 May 1998 / Accepted 8 October 1998 相似文献
20.
《Comparative biochemistry and physiology. C: Comparative pharmacology》1990,95(2):305-310
1. Cobalt, copper, zinc and cadmium injected into Carassius auratus in April (water temperature 16°C) increased liver ornithine decarboxylase and adenosylmethionine decarboxylase and not tyrosine aminotransferase activities independently of their accumulation within the liver.2. As previously shown, cadmium stimulated ornithine decarboxylase in November (16°C), but was ineffective in July (23°C).3. Acclimation of fish at 23°C in April and November caused the metal to become ineffective, but acclimation at 15°C in July failed to restore the response to cadmium.4. In February no significant changes occurred either at 14°C or at 23°C with any of the metals.5. Putrescine and polyamine concentrations essentially followed the response of ornithine decarboxylase activity. 相似文献