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1.
Quantitative and qualitative studies of the bacterial flora of farmed freshwater prawn (Macrobrachium rosenbergii) larvae in Saudi Arabia were performed, and isolates identified where possible. Physico‐chemical characteristics, bacterial counts, and the nature of the bacterial flora of larvae rearing tank water, sediment, tank wall surfaces, larval surface, supplied water, and feed were investigated. Bacterial counts ranged from 2.1 ± 1.3 × 105 to 2.2 ± 0.8 × 107 colony forming units (CFU) ml?1 in tank water; 4.4 ± 0.9 × 107 to 8.3 ± 1.7 ×109 CFU g?1 in tank sediment; 8.6 ± 1.0 × 102 to 9.8 ±0.7 × 104 CFU cm?2 on the tank wall surface; 1.3 ± 1.1 × 104 to 7.7 ± 1.6 × 106 CFU per larva surface, 7.9 ± 1.2 × 105 to 5.0 ± 1.5 × 107 CFU g?1 in washed larval tissue slurries, 9.1 ± 0.7 × 103 CFU ml?1 in supplied water, and 2.4 ± 1.9 ×1010 CFU g?1 in mixed feed. Fourteen bacterial genera were identified, including Chryseomonas sp., Vibrio spp., Cellulomonas sp., Aeromonas hydrophila, and Pasteurella sp. The tank water and sediment had similar bacteria to those on the prawn larvae. Chryseomonas sp., Cellulomonas sp. and Vibrio sp. were the most dominant species (prevalence >10%) in tank water; Chryseomonas sp., Pseudomonas alcaligenes and Shewanella putrefaciens in the sediment; Ps. alcaligenes and Cellulomonas sp. on the tank wall surface; Chryseomonas sp., and Cellulomonas sp. on the larval surface; and Chryseomonas sp., Vibrio vulnificus, Sh. putrefaciens and V. alginolyticus in the washed larval tissue slurries (prevalence 10%). Pseudomonas alcaligenes, Moraxella sp., Serratia liquefaciens, Gordona sp. and Burkholderia glumae were absent in larvae but identified in the culture water, tank sediment, and tank wall surface. Pseudomonas sp., Chryseomonas sp., Pasteurella sp. and V. alginolyticus were the prevalent bacteria (>12%) in supplied water. The feed contained V. alginolyticus, A. hydrophila and Cellulomonas sp. as the dominant bacteria (>13%). In the culture water and larvae samples, 83% of the feed and supplied water bacteria were identified. 相似文献
2.
Biological deinking of inkjet-printed paper using Vibrio alginolyticus and its enzymes 总被引:1,自引:0,他引:1
Recycling of office waste paper (photocopy, inkjet, and laser prints) is a major problem due to difficulty in removal of nonimpact
ink. Biological deinking of office waste paper is reported using several microorganisms and their enzymes. We report here
deinking and decolorization of the dislodged ink particles from inkjet printed paper pulp by a marine bacterium, Vibrio alginolyticus isolate no. NIO/DI/32, obtained from marine sediments. Decolorization of this pulp was achieved within 72 h by growing the
bacterium in the pulp of 3–6% consistency suspended in seawater. Immobilized bacterial cells in sodium alginate beads were
also able to decolorize this pulp within 72 h. The cell-free culture supernatant of the bacterium grown in nutrient broth
was not effective in deinking. However, when the culture was grown in nutrient broth supplemented with starch or Tween 80,
the cell-free culture supernatant could effectively deink and decolorize inkjet-printed paper pulp within 72 h at 30°C. The
culture supernatant of V. alginolyticus grown in the presence of starch or Tween 80 showed 49 U ml−1 and 33 U ml−1 amylase and lipase activities, respectively. Dialysis of these culture supernatants through 10 kDa cut-off membrane resulted
in a 35–40% reduction in their efficiency in decolorizing the pulp. It appears that amylase and lipase effectively help in
dislodging the ink particles from the inkjet printed-paper pulp. We hypothesize that the bacterium might be inducing the formation
of low molecular weight free radicals in the culture medium, which might be responsible for decolorization of the pulp. 相似文献
3.
S.H. Cai Y.S. Lu Z.‐H. Wu J.C. Jian B. Wang Y.C. Huang 《Letters in applied microbiology》2010,50(5):480-485
Aims: The purpose of this study was to develop a loop‐mediated isothermal amplification (LAMP) method for the rapid, sensitive and simple detection of Vibrio alginolyticus in mariculture fish. Methods and Results: LAMP primers were designed by targeting the gyrB gene. With Bst DNA polymerase, the target DNA can be clearly amplified for 60 min at 64°C in a simple water bath. The detection sensitivity of the LAMP assay for the detection of V. alginolyticus is about 3·7 × 102 CFU ml?1 (3·7 CFU per reaction). LAMP products could be judged with agar gel or naked eye after the addition of SYBR Green I. There were no cross‐reactions with other bacterial strains indicating a high specificity of the LAMP. The LAMP method was applied to detect V. alginolyticus‐infected fish tissues effectively. Conclusions: The LAMP established in this study is a simple, sensitive, specific, inexpensive and rapid protocol for the detection of V. alginolyticus. Significance and Impact of the Study: This LAMP method provides an important diagnostic tool for the detection of V. alginolyticus infection both in the laboratory and field. 相似文献
4.
P. A. Sansberro H. Y. Rey L. A. Mroginski M. M. Collavino 《Journal of Plant Growth Regulation》1998,17(2):101-105
The effects of benzyladenine (BAP), kinetin (KIN), zeatin (ZEA), isopentenyladenine (2iP), and thidiazuron (TDZ) were studied
on in vitro growth of rudimentary embryos of Ilex paraguariensis St. Hil. Heart stage zygotic embryos were removed from seeds of immature, light green fruits and cultured aseptically on
quarter-strength Murashige and Skoog medium containing 3% sucrose, 0.65% agar, and supplemented with or without three concentrations
of BAP, KIN, ZEA, 2iP, or TDZ. Cultures were incubated in darkness at 27 ± 2°C. Media containing 4.4 × 10−6
m BAP, 4.6 × 10−6
m KIN, or 4.9 × 10−6
m 2iP were totally ineffective in inducing embryo growth after culture for 28 days. However, lower concentrations of these
compounds (4.4 × 10−8
m BAP, 4.6 × 10−8
m KIN, 4.5 × 10−8
m ZEA, or 4.9 × 10−8
m 2iP) promoted embryo growth. TDZ at 9.9 × 10−9
m, 9.9 × 10−8
m, or 9.9 × 10−7
m induced embryo growth at similar rates. The maximum percentage of embryos converted to seedlings was achieved when the medium
was supplemented with 4.5 × 10−7
m ZEA.
Received August 1, 1997; accepted February 19, 1998 相似文献
5.
The use of clove oil as a potential anaesthetic for freshwater amphipods was examined at 20 °C. Individuals of Gammarus minus, a common species in southern Illinois, USA, spanning the entire body size range (4.3–14.3 mm), were used to test four anaesthetic
concentrations varying from 1.48 × 10−4 ml ml−1 to 5.9 × 10−4 ml ml−1. Small-bodied individuals (mean size = 5.4 mm ± 0.27SE) were used to test additional concentrations, up to 14.7 × 10−4 ml ml−1, a 10-fold span, to identify potential lethal concentrations. At the lowest concentration, time to anaesthesia and recovery
was constant at all body sizes. For the three next higher concentrations, time to anaesthesia decreased with increasing concentration
while recovery time increased. Activity of amphipods was not affected by the ethanol carrier. In addition, activity did not
differ between amphipods that had recovered from anaesthesia and unexposed amphipods. At clove oil concentrations of 8.84
× 10−4 ml ml−1 and 14.7 × 10−4 ml ml−1, mortality was 7 and 40%, respectively, indicating, that 5.9 × 10−4 ml ml−1 was a safe working concentration. No mortality was observed with Gammarus acherondytes, a federally endangered cave amphipod on which the protocol with 80 μl of stock was used in the field. The method enabled
us to obtain information on the endangered amphipod which normally would have required the sacrifice of individuals. Thus,
research can continue on species for which population numbers are low and for which basic information is needed to formulate
meaningful recovery plans. 相似文献
6.
A. Pires S. L. Coon M. G. Hadfield 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,181(3):187-194
The content of catecholamines and dihydroxyphenylalanine in larvae of the nudibranch Phestilla sibogae was analyzed by high-performance liquid chromatography with electrochemical detection. Dihydroxyphenylalanine, norepinephrine
and dopamine were identified in larvae of all ages examined (5 through 12 days post-fertilization). Dihydroxyphenylalanine
could be accurately quantified only in larvae of ages 8 through 12 days, when its average concentration increased from 0.62
to 6.71 × 10−2 pmol μg protein−1. Between ages 5 and 12 days dopamine rose from 0.081 to 0.616 pmol μg protein−1, and norepinephrine from 0.45 to 2.17 × 10−2 pmol μg protein−1. Dihydroxyphenylalanine, dopamine and norepinephrine were also measured at different stages of metamorphic progress in 10-
to 12-day larvae. Dihydroxyphenylalanine increased by a factor of 2.4 between the onset and completion of metamorphosis, but
levels of dopamine and norepinephrine remained stable. One millimolar alpha-methyl-dl-m-tyrosine, an inhibitor of catecholamine synthesis, inhibited natural metamorphosis and depleted endogenous norepinephrine
and especially dopamine, respectively, to 75% and 35% of control values. The existence of unexpectedly high levels of catecholamines
in metamorphically competent larvae, and the association of catecholamine depletion with inhibition of metamorphosis, indicate
that these compounds may participate in the control of gastropod development.
Accepted: 18 April 1997 相似文献
7.
The distributions of bacterial populations in sea ice and underlying seawater were investigated on the continental shelf of
the “Terre Adélie” area. A reference station was sampled weekly from January 1991 to January 1992. In winter, the survey included
a minimum of six sampling layers: surface and bottom ice, brine, seawater from the interface, and at 0.5 and 2 m depth. In
seawater, the total bacterial abundance ranged from 0.5 × 105 cells ml−1 in July to 6.0 × 105 cells ml−1 after ice break. Values reaching 2.5 × 106 cells ml−1 were recorded in the overlying ice cover. Mean cell volumes were twice as high in brine as in seawater. The saprophytic bacterial
abundance ranged from 5.0 × 104 CFU (colony-forming units) ml−1 in some winter interface samples to less than 1.0 × 103 CFU ml−1 in most of the summer seawater samples. In sea ice a clear decreasing gradient for most of the studied bacterial parameters
from the surface layers towards the bottom layer was found. The ice cover had a discernible impact on underlying seawater,
but its influence was restricted to a limited interface layer. 相似文献
8.
Aims: To develop probiotics for the control of vibriosis caused by Vibrio anguillarum and Vibrio ordalii in finfish. Methods and Results: Kocuria SM1, isolated from the digestive tract of rainbow trout, was administered orally to rainbow trout (Oncorhynchus mykiss) for 2 weeks at a dose equivalent to c. 108 cells per g of feed and then challenged intraperitoneally with V. anguillarum and V. ordalii. Use of SM1 led to a reduction in mortalities to 15–20% compared to 74–80% mortalities in the controls. SM1 stimulated both cellular and humoral immune responses in rainbow trout, by elevation of leucocytes (5·5 ± 0·8 × 106 ml?1 from 3·7 ± 0·8 × 106 ml?1), erythrocytes (1·2 ± 0·1 × 108 ml?1 from 0·8 ± 0·1 × 108 ml?1), protein (23 ± 4·4 mg ml?1 from 16 ± 1·3 mg ml?1), globulin (15·7 ± 0·2 mg ml?1 from 9·9 ± 0·1 mg ml?1) and albumin (7·3 ± 0·2 mg ml?1 from 6·1 ± 0·1 mg ml?1) levels, upregulation of respiratory burst (0·05 ± 0·01 from 0·02 ± 0·01), complement (56 ± 7·2 units ml?1 from 40 ± 8·0 units ml?1), lysozyme (920 ± 128·8 units ml?1 from 760 ± 115·3 units ml?1) and bacterial killing activities. Conclusions: Kocuria SM1 successfully controlled vibriosis in rainbow trout, and the mode of action reflected stimulation of the host innate immune system. Significance and Impact of the Study: Probiotics can contribute a significant role in fish disease control strategies, and their use may replace some of the inhibitory chemicals currently used in fish farms. 相似文献
9.
Perrig D Boiero ML Masciarelli OA Penna C Ruiz OA Cassán FD Luna MV 《Applied microbiology and biotechnology》2007,75(5):1143-1150
We evaluated phytohormone and polyamine biosynthesis, siderophore production, and phosphate solubilization in two strains
(Cd and Az39) of Azospirillum brasilense used for inoculant formulation in Argentina during the last 20 years. Siderophore production and phosphate solubilization
were evaluated in a chemically defined medium, with negative results. Indole 3-acetic acid (IAA), gibberellic acid (GA3), and abscisic acid (ABA) production were analyzed by gas chromatography-mass spectrometry. Ethylene, polyamine, and zeatin
(Z) biosynthesis were determined by gas chromatography-flame ionization detector and high performance liquid chromatography
(HPLC-fluorescence and -UV), respectively. Phytohormones IAA, Z, GA3, ABA, ethylene, and growth regulators putrescine, spermine, spermidine, and cadaverine (CAD) were found in culture supernatant
of both strains. IAA, Z, and GA3 were found in all two strains; however, their levels were significantly higher (p < 0.01) in Cd (10.8, 2.32, 0.66 μg ml−1). ABA biosynthesis was significantly higher (p < 0.01) in Az39 (0.077 μg ml−1). Ethylene and polyamine CAD were found in all two strains, with highest production in Cd cultured in NFb plus l-methionine (3.94 ng ml−1 h−1) and Az39 cultured in NFb plus l-lysine (36.55 ng ml−1 h−1). This is the first report on the evaluation of important bioactive molecules in strains of A. brasilense as potentially capable of direct plant growth promotion or agronomic yield increase. Az39 and Cd showed differential capability
to produce the five major phytohormones and CAD in chemically defined medium. This fact has important technological implications
for inoculant formulation as different concentrations of growth regulators are produced by different strains or culture conditions. 相似文献
10.
Peter W. Inglis Rubia B. C. Sarmento Camila F. C. Gavião Heloisa Frazão M. Cléria Valadares-Inglis 《World journal of microbiology & biotechnology》2006,22(10):1083-1085
Summary An insertional mutant of Metarhizium anisopliae is described with enhanced submerged conidiation. In a 500 ml submerged culture, this mutant produces a mean of 4.05 × 108 propagules ml−1 from an inoculum of 1 × 106 conidia, where the parental strain accumulates only 3.75 × 104 propagules ml−1. 相似文献
11.
Gabriel Moura Mascarin Sérgio Batista Alves Fátima Teresinha Rampelotti-Ferreira Mariana Ragassi Urbano Clarice Garcia Borges Demétrio Italo DelaliberaJr. 《BioControl》2010,55(5):657-671
In this study a Brazilian granulovirus strain, PhopGV, isolated from the potato tuber moth (PTM) Phthorimaea operculella, was investigated regarding its potential for biological control and in vivo production. The relationship between mortality
of P. operculella larvae and virus concentration was determined at different temperatures on potato tubers and susceptibility of P. operculella to PhopGV was also determined on potato leaves. Virulence of PhopGV to P. operculella was not affected by temperatures from 18 to 30°C. The median lethal concentration (LC50) of larvae fed on potato foliage treated with PhopGV was not higher than that verified with larvae fed on treated tubers.
Optimal conditions for production of virus-infected larvae were obtained by using the virus suspensions of 41 × 105, 6.3 × 105 and 62 × 105 OBs ml−1 at 18, 24 and 30°C, which resulted in 32.0, 31.4 and 34.8% of infected larvae collected, respectively. The maximum percentage
of infected larvae recovered from tubers was not affected by temperature. However, time for production of virus-infected larvae
was longer at 18°C and shorter at 30°C. Persistence of PhopGV was determined on stored tubers and we observed that the virus
remained effective for at least two months, causing up to 84.2% mortality of P. operculella at 1 × 107 OBs ml−1. The pathogen was also highly virulent to tomato pinworm, Tuta absoluta, inflicting high percentage of mortality, delaying larval growth and inhibiting pupation. This Brazilian PhopGV strain has
potential to control PTM larvae on potato tubers at a broad range of temperature and can be produced in vivo using virus-treated
tubers. 相似文献
12.
We evaluated the combined effects of algal (Chlorella vulgaris) food levels (low, 0.5 × 106 (or 2.9 μg C ml−1); and high, 1 × 106 cells ml−1 (or 5.8 μg C ml−1)) and zinc concentrations (0, 0.125, and 0.250 mg l−1 of ZnCl2) on the competition between two common planktonic rotifers Anuraeopsis fissa and Brachionus rubens using their population growth. Median lethal concentration data (LC50) (mean ± 95% confidence intervals) showed that B. rubens was more resistant to zinc (0.554 ± 0.08 mg l−1) than A. fissa (0.315 ± 0.07 mg l−1). A. fissa when grown alone or with Zn was always numerically more abundant than B. rubens. When grown in the absence of zinc, under low- and high-food levels, the peak abundances of A. fissa varied from 251 ± 24 to 661 ± 77 ind. ml−1, respectively, and the corresponding maxima for B. rubens were 52 ± 3 and 102 ± 18 ind. ml−1. At a given food level, competition for food reduced the peak abundances of both rotifers considerably. Increase in Zn concentration
also lowered the rotifer abundances. The impact of zinc on competition between the two-rotifer species was evident at low-food
level, mainly for A. fissa. At zinc concentrations of 0 and 0.125 mg l−1, the populations of both rotifers continued to grow for about 10 days, but thereafter B. rubens began to decline. Role of zinc on the competitive outcome of the two species is discussed in relation to the changing algal
densities in natural water bodies. 相似文献
13.
We discuss the energetics of a cladoceran, Simocephalus vetulus at different temperatures (8.0 ± 1.0, 15.0 ± 1.0, 21.0 ± 1.0 and 28.0 ± 1.0 °C) and food (Chlamydomonas sp.) concentrations (25 × 103, 50 × 103, 75 × 103 and 100 × 103 cells ml−1). Increase in temperature accelerated ingestion and, to some extent, oxygen consumption. The study revealed a high reproduction
efficiency in S. vetulus. Net growth efficiency (ECI) was higher (13.17–41.18%) in pre-adults than in adults (2.71–8.40%). The assimilated energy
(A) increased with increasing food concentration at all temperatures. Assimilation efficiency (AD) decreased with increasing
food concentrations. The energy used for growth (P) was nearly constant at all food levels because the egested energy increased
and assimilation efficiency decreased as food concentration increased. 相似文献
14.
A Bacillus sp. RE was resistant to chromium and reduced Cr(VI) without accumulating chromium inside the cell. When Cr(VI) was 10 and
40 μg ml−1, >95% of the total Cr(VI) was reduced in 24 and 72 h of growth, respectively, whereas at 80 μg Cr(VI) ml−1 only 50% of Cr(VI) was reduced. However growth was not affected; the cell mass was 0.7–0.8 mg ml−1 in all cases. The cell-free extract showed Cr(VI) reducing enzyme activity which was enhanced (>5 fold) by NADH and NADPH.
Like whole cells the enzyme also reduced Cr(VI) with decreasing efficiency on increasing Cr(VI) concentration. The enzyme
activity was optimal at pH 6.0 and 30 °C. The enzyme was stable up to 30 °C and from pH 5.5 to 8, but from pH 4 to 5 the enzyme
was severely destabilized. Its Km and Vmax were 14 μm and 3.8 nmol min−1 mg−1 respectively. The enzyme activity was enhanced by Cu2+ and Ni2+ and inhibited by Hg2+.
Received 21 September 2005; Revisions requested 5 October 2005; Revisions received 16 November 2005; Accepted 16 November
2005 相似文献
15.
Arthrospira
platensis SAG 21.99 and the isolated bacteria (Halomonas spp., Staphylococcus sp., etc.) from the culture of A. platensis SAG 21.99 were treated with five antibiotics to determine the minimal lethal concentrations. The combination of a washing
step and a consecutive treatment with antibiotics, imipenem (100 μg ml−1), neomycin (100 μg ml−1) and cycloheximide (20 μg ml−1), treatment step was highly effective in eliminating bacteria. An axenic culture of A. platensis SAG 21.99 could be induced within 3 days using this method. This technique is a simple and rapid method for obtaining axenic
cultures of filamentous cyanobacteria. 相似文献
16.
The effect of several plant growth regulators on the number of tumors developing on potato tuber discs (Solatium tuberosum L. cv. Radka) inoculated withAgrobacterium tumefaciens, strain C 58 was studied. The plant growth regulators used in appropriate range of concentrations stimulated the formation
of tumors byA. tumefaciens.
Naphthaleneacetic acid (NAA) was most active in concentration of 10−4 mg ml−1. Kinetin gave a biphasic response with optimal promotions of tumor initiation at 10−4 − 2 × 10−3 mg ml−1. High kinetin concentration (10−1 mg ml−1) inhibited the formation of tumors completely. Indoleacetic acid (IAA) stimulated the initiation of tumors in the same range
of concentrations as kinetin, except that very high concentrations did not inhibit but enhanced tumor formation. 2,4-diehlorphenoxyacetic
acid (2,4-D) showed a biphasic response with maxima in 10−4 mg ml−1 and 10−1 mg ml−1. All the tumors scored for nopaline production showed nopaline synthase activity independently whether their formation was
stimulated by l0−1 mg ml−1 IAA or they were initiated without any treatment by plant growth regulators. 相似文献
17.
David C. Anuforo Daniel Acosta Robert V. Smith 《In vitro cellular & developmental biology. Plant》1978,14(12):981-988
Summary A method for preparing primary monolayer cultures of postnatal rat hepatocytes has been developed in our laboratory. Growing
cultures in arginine-deficient medium inhibits fibroblast overgrowth, and relatively pure cultures of parenchymal hepatocytes
are obtained. This cell culture system has been used to study the cytotoxicity of two hepatotoxic agents, tetracycline and
norethindrone. Caffeine was evaluated as an agent thought to be relatively nontoxic to liver. Cytotoxicity was evaluated by
phase-contrast microscopy of cellular morphology and by measurement of leakage of intracellular enzymes [arginosuccinate lyase
(ASAL), lactate dehydrogenase (LDH), glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), and
acid phosphatase (AP)] into the culture medium. Hepatic cultures were treated with each of the agents in concentrations ranging
from 5×10−6 to 1×10−3
m and for durations from 1 to 24 hr. ASAL was found to be the most sensitive in predicting early cell injury and AP the least
sensitive; the other three enzymes tested were intermittent in value and equally sensitive in evaluating cytotoxicity. Treatment
of the cultures with tetracycline (5×10−4
m) for 6 hr resulted in ASAL leakage that was 400% of control values; and norethindrone (5×10−4
m) for 6 hr caused a 250% increase relative to controls. The hepatotoxic agents demonstrated a dose- and timedependence of
cytotoxicity in the cultures. In contrast, caffeine was relatively nontoxic to the cultures.
Part of this investigation was presented orally at the 17th Annual Meeting of the Society of Toxicology, San Francisco, March
13, 1978. 相似文献
18.
Kemel Jellouli Ali Bougatef Laila Manni Rym Agrebi Rayda Siala Islem Younes Moncef Nasri 《Journal of industrial microbiology & biotechnology》2009,36(7):939-948
A protease-producing bacterium was isolated from an alkaline wastewater of the soap industry and identified as Vibrio metschnikovii J1 on the basis of the 16S rRNA gene sequencing and biochemical properties. The strain was found to over-produce proteases
when it was grown at 30°C in media containing casein as carbon source (14,000 U ml−1). J1 enzyme, the major protease produced by V. metschnikovii J1, was purified by a three-step procedure, with a 2.1-fold increase in specific activity and 33.3% recovery. The molecular
weight of the purified protease was estimated to be 30 kDa by SDS-PAGE and gel filtration. The N-terminal amino acid sequence
of the first 20 amino acids of the purified J1 protease was AQQTPYGIRMVQADQLSDVY. The enzyme was highly active over a wide
range of pH from 9.0 to 12.0, with an optimum at pH 11.0. The optimum temperature for the purified enzyme was 60°C. The activity
of the enzyme was totally lost in the presence of PMSF, suggesting that the purified enzyme is a serine protease. The kinetic
constants K
m and K
cat of the purified enzyme using N-succinyl-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide were 0.158 mM and 1.14 × 105 min−1, respectively. The catalytic efficiency (K
cat
/K
m) was 7.23 × 108 min−1 M−1. The enzyme showed extreme stability toward non-ionic surfactants and oxidizing agents. In addition, it showed high stability
and compatibility with some commercial liquid and solid detergents. The aprJ1 gene, which encodes the alkaline protease from V. metschnikovii J1, was isolated, and its DNA sequence was determined. The deduced amino acid sequence of the preproenzyme differs from that
of V. metschnikovii RH530 detergent-stable protease by 12 amino acids, 7 located in the propeptide and 5 in the mature enzyme. 相似文献
19.
Résumé Les larves deTrichoplusia ni (Hübner) infectées parVairimorpha (=Nosema) necatrix (Kramer) présentent des sympt?mes chroniques, semi-chroniques et aigus selon les doses de spores deV. necatrix (5 à 500, 5.103 à 5.105 et 5.106 par larve, respectivement) ingérées par larve.V. necatrix parasite principalement le corps adipeux et les tissus des muscles quand les larves ont des sympt?mes chroniques, tandis
que les larves manifestent les sympt?mes aigus lorsque les microsporidies attaquent principalement l’intestin moyen. L’histopathologie
de la maladie est étudiée.
Ce travail a fait l’objet d’une thèse de 3e cycle, présentée à l’Université de Paris VI en mars 1977, parWei Hsuang Chu. 相似文献
Summary Infection of larvae ofTrichoplusia ni (Hübner) byVairimorpha, (=Nosema) necatrix was classified as chronic, semi-chronic and acute symptoms depending on the quantity of spores (5 to 500, 5×103 to 5×105, and 5×106 per larva, respectively) ingested per larva.V. necatrix infects mainly the fat body and some muscle tissue of larvae with chronic symptoms and mainly midgut tissue of larvae with acute symptoms.V. necatrix caused death in 3 to 4.5 days when a larva ingested 5×106 spores. The histopathology of the disease was studied.
Ce travail a fait l’objet d’une thèse de 3e cycle, présentée à l’Université de Paris VI en mars 1977, parWei Hsuang Chu. 相似文献
20.
In previous experiments, rates of picoplankton uptake into coral communities were controlled by sponge and ascidian biomass.
Those experimental communities, however, had relatively few sponges and ascidians. In contrast, turbulent transport of particles
into the momentum boundary layers can limit particle removal by layered, dense bivalve populations. In this study, the role
of water velocity in controlling particulate nutrient-uptake by rubble communities was evaluated, in which the rubble was
more completely covered by sponges and ascidians. Picoplankton uptake was proportional to concentration over a range of cell
concentrations from 3.0 × 105 to 9.5 × 105 heterotrophic bacteria ml−1, 4.1 × 104 to 1.2 × 105
Synechococcus sp. ml−1 and 6.3 × 103 to 1.8 × 104 picoeukaryotes ml−1. The first-order uptake rate constants, normalized to sponge and ascidian biomass, were similar to previous experimental
communities. Picoplankton uptake increased 1.6-fold over a 7-fold change in water velocity, 0.05–0.35 m s−1. This increase has been interpreted as a result of higher turbulent transport within the rough coral community (canopy),
as indicated by a 1.6-fold increase in the bottom friction with increasing water velocity. 相似文献