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1.
Bacillus subtilis and Escherichia coli K12 (both transformed for human leukocyte interferon production) and Escherichia coli B/r and Sporotrichum thermophile (a deuteromycete) were cultivated in submersed culture and the culture fluorescence recorded on-line using a fluorometer. During the cultivation of B. subtilis the signal from the fluorometer correlated with cell density and interferon production and thus could be used for process control (interferon production). However, the culture fluorescence of the other organisms did not increase (S. thermophile), was too weak to be measured with the fluorometer used (E. coli transformed for interferon production), or the signal from the fluorometer was not an accurate measure of the culture fluorescence because of the accumulation of a fluorophor in the culture medium (E. coli B/r). 相似文献
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3.
Alzate JF Alvarez-Barrientos A González VM Jiménez-Ruiz A 《Apoptosis : an international journal on programmed cell death》2006,11(2):161-171
An increasing number of reports indicate that single-celled organisms are able to die following what seems to be an ordered
program of cell death with strong similarities to apoptosis from higher eukaryotes. DNA degradation and several other apoptotic-like
processes have also been described in the parasitic protozoa Leishmania. However, the existence of an apoptotic death in this parasite is still a matter of controversy. Our results indicate that
most of the processes of macromolecular degradation and organelle dysfunction observed in mammalian cells during apoptosis
can also be reproduced in promastigotes of the genus Leishmania when incubated at temperatures above 38°C. These processes can be partially reversed by the expression of the anti-apoptotic
mammalian gene Bcl-XL, which suggests that this family of apoptosis-regulating proteins was present very early in the evolution of eukaryotic cells. 相似文献
4.
The use of mysid shrimp, particularly the genusMysidopsis, along with specific testing procedures, has become accepted in aquatic toxicology. Investigators have developed methodologies for both culture and testing of these organisms. Acute and chronic (life cycle) toxicity tests in addition to dredge spoil and effluent tests with mysids are now becoming common. Attempts have been made to use mysids as test organisms in behavioral, physiological, nutritional, and food-chain studies. In general,Mysidopsis spp. have been shown to be as sensitive or more sensitive to toxic substances than other marine species tested. The ease of handling and culture, relative sensitivity to toxicants, short life cycle, small size and direct larval development make these organisms desirable for research purposes. Continued research using mysid species will probably demonstrate even greater usefulness of these organisms in assessment of pollutant impacts on estuarine or marine communities. 相似文献
5.
Cell death in trichomonads: new insights 总被引:2,自引:2,他引:0
Tritrichomonas foetus is an amitochondriate parasite that possesses hydrogenosomes, unusual anerobic energy-producing organelles. In these organisms the “mitochondrial cell death machinery” is supposed to be absent, and the mechanisms that lead to cell demise remain to be elucidated. The presence of a cell death program in trichomonads has already been reported, suggesting the existence of a caspase-like execution pathway in such organisms. Here we demonstrate the alterations provoked by the fungicide griseofulvin and raise the possibility that other cell death pathways may exist in T. foetus. Dramatic changes in trichomonads morphology are presented after griseofulvin treatment, such as intense plasma membrane and nuclear envelope blebbing, nucleus fragmentation, and an abnormal number of oversized vacuoles. One important finding was the exposition of phosphatidylserine (PS) in the outer leaflet of the plasma membrane in cells after drug treatment, and also the presence of a high amount of misshapen flagella and tubulin precipitates as vacuolar contents, suggesting an autophagic process of abnormal cellular elements. Interestingly, immunoreactivity for activated caspase-3 was not detected during griseofulvin treatment, a finding distinct from the observed when this cell was treated with H2O2. The possibility of the existence of different pathways to cell death in trichomonads is discussed. 相似文献
6.
Comparison of the three-dimensional structure of hyperthermophilic and mesophilic β-glycosidases shows differences in secondary
structure composition. The enzymes from hyperthermophilic archaea have a significantly larger number of β-strands arranged
in supernumerary β-sheets compared to mesophilic enzymes from bacteria and other organisms. Amino acid replacements designed
to alter the structure of the supernumerary β-strands were introduced by site directed mutagenesis into the sequence encoding
the β-glycosidase from Sulfolobus solfataricus. Most of the replacements caused almost complete loss of activity but some yielded enzyme variants whose activities were
affected specifically at higher temperatures. Far-UV CD spectra recorded as a function of temperature for both wild type β-glycosidase
and mutant V349G, one of the mutants with reduced activity at higher temperatures, were similar, showing that the protein
structure of the mutant was stable at the highest temperatures assayed. The properties of mutant V349G show a difference between
thermostability (stability of the protein structure at high temperatures) and thermophilicity (optimal activity at high temperatures). 相似文献
7.
A. C. Amadioha 《World journal of microbiology & biotechnology》1993,9(5):599-600
Rhizoctonia bataticola produced oxalic acid in vitro and in vivo during pathogenesis of patato tuber. Polygalacturonase (PG) was also detected in culture filtrates of the rot-causing organism. Levels of maceration and cell death in tuber tissue were higher when a mixture of oxalic acid and PG was used than when either oxalic acid or PG were used alone. 相似文献
8.
Biotechnology and aquaculture of rotifers 总被引:13,自引:0,他引:13
Biotechnology can be defined as any technology that involves living organisms or their derivatives. In applying this definition to rotifers, we focus on their contribution in culturing of early larval stages of marine fish. After almost four decades of marine fish culture in captivity, the success of this worldwide industry is still quite dependent on mass culture of the species Brachionus plicatilis and B. rotundiformis. In mass culture, the rotifers are continuously driven to reproduce at high rates, in relatively extreme environmental conditions of high population density and high loads of organic matter. Therefore, the success of mass cultures and future improvements in these systems relies on a close interaction between basic and applied studies of rotifers. In the present review, we will attempt to analyze why rotifers are suitable for early life stages of fish and to describe, in general, methodologies that have been devised for reliable supply of rotifers in large quantities. Problems associated with rotifer production, nutritional quality and effect on fish health and nutrition, will be discussed. Research on B. plicatilis and B. rotundiformis has increased enormously during the past three decades and these two species are the best-studied rotifers so far. While much of the research on these species is directed or devoted to the needs of aquaculture industry, they are also used as models for addressing basic biological questions, due to the relative ease of culture and their availability. Studies on feeding, pheromones, speciation in rotifers, the occurrence and putative hormones involved in sexual and asexual reproduction and production of resting eggs, are few examples of such studies. Rotifers will probably maintain their role as food organism for fish larvae, in spite of attempts to replace them with more accessible formulated food. Development of new culture methods that will improve the nutritional quality and production efficiency of rotifers may result in more diversified and flexible tasks for these organisms in aquaculture. 相似文献
9.
Laboratory culture of fairy shirmps using baker's yeast as basic food in a flow-through system 总被引:1,自引:1,他引:0
Alejandro M. Maeda-Martínez Hortencia Obergón-Barboza Henri J. Dumont 《Hydrobiologia》1995,298(1-3):141-157
We designed and standardized a culture method for freshwater anostracans using diets free of live algae.Thamnocephalus platyurus andBranchinecta lindahli were used as test organisms.We used baker's yeast as basic food and added inert particles (clay or amorphic silicium dioxide) to improve the digestion of the yeast. A flow-through culture system was used, according to a fixed feeding schedule, to supply separately, culture medium (tap water), food, and inert particle suspensions. Three variants with baker's yeast as basic, food were compared for survival, growth, and reproduction. A diet of solely baker's yeast (diet 1) or baker's yeast supplemented with vegetal oil containing ß-carotene (diet 2) was unsuitable for reproduction ofT. platyurus. Cyst production was only achieved when diet 2 was supplemented with fish oil andSpirulina powder (diet 3). This suggests that not only a digestibility problem, but also nutritional deficiencies are present in baker's yeast. 相似文献
10.
The growth, biochemical composition and fatty acid profiles of six Antarctic microalgae cultured at different temperatures, ranging from 4, 6, 9, 14, 20 to 30 ∘C, were compared. The algae were isolated from seawater, freshwater, soil and snow samples collected during our recent expeditions to Casey, Antarctica, and are currently deposited in the University of Malaya Algae Culture Collection (UMACC). The algae chosen for the study were Chlamydomonas UMACC 229, Chlorella UMACC 234, Chlorella UMACC 237, Klebsormidium UMACC 227, Navicula UMACC 231 and Stichococcus UMACC 238. All the isolates could grow at temperatures up to 20 ∘C; three isolates, namely Navicula UMACC 231 and the two Chlorella isolates (UMACC 234 and UMACC 237) grew even at 30 ∘C. Both Chlorella UMACC 234 and Stichococcus UMACC 238 had broad optimal temperatures for growth, ranging from 6 to 20 ∘C (μ = 0.19 – 0.22 day–1) and 4 to 14 ∘C (μ = 0.13 – 0.16 day–1), respectively. In contrast, optimal growth temperatures for NaviculaUMACC 231 and Chlamydomonas UMACC 229 were 4 ∘C (μ = 0.34 day–1) and 6–9 ∘C (μ = 0.39 – 0.40 day–1), respectively. The protein content of the Antarctic algae was markedly affected by culture temperature. All except Navicula UMACC 231 and Stichococcus UMACC 238 contained higher amount of proteins when grown at low temperatures (6–9 ∘C). The percentage of PUFA, especially 20:5 in Navicula UMACC 231 decreased with increasing culture temperature. However, the percentages of unsaturated fatty acids did not show consistent trend with culture temperature for the other algae studied. 相似文献
11.
Mendoza LM de Nadra MC Bru E Farías ME 《Journal of industrial microbiology & biotechnology》2009,36(2):229-237
The influence of two physicochemical factors involved in winemaking, temperature and SO2, on the kinetics and metabolic behavior of Kloeckera apiculata and Saccharomyces cerevisiae was examined. Highest biomass was reached at 15 and 25°C for K. apiculata and S. cerevisiae, respectively. Pure cultures of K. apiculata died off early with increasing temperature, but in co-culture with S. cerevisiae it showed higher viability and a change in the death curve from exponential to linear. Statistical analysis revealed that
metabolite production was significantly different for the three cultures and also at the different fermentation temperatures.
Besides, the interaction between culture type and temperature was significant. At temperatures from 15 to 30°C the mixed culture
showed similar ethanol and lower acetic acid production compared with a pure culture of K. apiculata. SO2 addition slightly increased survival of the non-Saccharomyces species in pure and mixed cultures. Statistical evaluation indicated that culture type and SO2 addition significantly affected metabolite production, but the interaction between culture and SO2 was not significant. These results contribute to current knowledge of enological factors and their effect on prevalence and
fermentative activities of the composite yeast flora and the statistical significance emphasizes the importance of the combined
influence of the culture type and physicochemical factors on the production of fermentation metabolites. 相似文献
12.
To develop a risk-assessment system for small organisms accidentally introduced with imported organisms, we investigated as
a first case study parasitic canestriniid mites, which have been imported into Japan via pet lucanid beetles from Southeast
Asia. We collected mites from pinned specimens of Japanese lucanids collected before 1999—when the Japanese government lifted
a ban on the import of the beetles—and living mites from imported and native lucanid beetles collected after that. No foreign
canestriniid was found on any of the native Japanese beetles. Because the mites collected from imported beetles were different
from Japanese species, we conclude that the foreign mites have not yet established wild populations in Japan. However, because
the Japanese mites migrate between hosts without host physical contact, introduced mites are assumed to be able to migrate
from a foreign to Japanese host. In fact, possible contamination was observed in pet shops. We observed host switching in
only one direction: Southeast Asian Canestrinia nr spectanda switched to Japanese Dorcus rectus, but Japanese Coleopterophagus berlesei never switched to Indonesian D. titanus. The foreign mites reproduced between 15°C and 25°C, suggesting that the mites could survive in mountainous sites in southern
Japan and at low elevations in northern Japan. The ability of foreign parasitic canestriniids to infect and survive on Japanese
hosts at temperatures characteristic of much of Japan leads us to conclude that these mites present a potential risk to Japanese
endemic canestriniids as well as to native Japanese lucanids. 相似文献
13.
Screening of Rhizobium leguminosarum bv. phaseoli strains showed some that were able to nodulate common beans (Phaseolus vulgaris L.) at high temperatures (35 and 38°C/8 h/day). The nodulation ability was not related to the capability to grow or produce
melanin-like pigment in culture media at high temperatures. However, nodules formed at high temperatures were ineffective
and plants did not accumulate N in shoots. Two thermal shocks of 40°C/8 h/day at flowering time drastically decreased nitrogenase
activity and nodule relative efficiency of plants otherwise grown at 28°C. Recovery of nitrogenase activity began only after
seven days, when new nodules formed; total incorporation of N in tops did not recover for 2 weeks. Non-inoculated beans receiving
mineral N were not affected by the thermal shock, and when growing continuously at 35 or 38°C had total N accumulated in shoots
reduced by only 18%. 相似文献
14.
Paalme T Nisamedtinov I Abner K Laht TM Drews M Pehk T 《Antonie van Leeuwenhoek》2006,89(3-4):443-457
The advantage of using 13C-labelled glucose in metabolic studies is that it is an important carbon and energy source for almost all biotechnologically and medically important organisms. On the other hand, the disadvantage is its relatively high cost in the labelling experiments. Looking for cheaper alternatives we found that 13C-[2] acetate or 13C-[1,2] acetate is a prospective compound for such experiments. Acetate is well incorporated by many organisms, including mammalian and insect cell cultures as preferred source of acetyl-CoA. Our experimental results using 13C NMR demonstrated that acetate was efficiently incorporated into glutamate and alanine secreted by the insect cell culture. Using D-stat culture of Saccharomyces uvarum on glucose/13C-acetate mineral media we demonstrated that the labelling patterns of proteinogenic amino acids can be well predicted on the basis of specific substrate consumption rates using the modified scheme of yeast metabolism and stoichiometric modelling. According to this scheme aspartate and alanine in S. uvarum under the experimental conditions used is synthesised in the mitochondria. Synthesis of alanine in the mitochondria was also demonstrated for Spodoptera frugiperda. For both organisms malic enzyme was also operative. For S. uvarum it was shown that the activity of malic enzyme is sufficient for supporting the mitochondrial biosynthetic reactions with NADPH. 相似文献
15.
The free fatty acid and phospholipid composition of 4 psychrophilic marineVibrio spp. have been determined in chemostat culture with glucose as the limiting substrate over a temperature range 0–20°C. All the isolates show maximum glucose and lactose uptake at 0°C and this correlates with maximum cell yield. None of the isolates contain fatty acids with a chain length exceeding 17 carbon atoms.Vibrio AF-1 andVibrio AM-1 respond to decreased growth temperatures by synthesizing increased proportions of unsaturated fatty acids (C15:1, C16:1 and C17:1) whereas inVibrio BM-2 the fatty acids undergo chain length shortening. The fourth isolate (Vibrio BM-4) contains high levels (60%) of hexadecenoic acid at all growth temperatures and the fatty acid composition changes little with decreasing temperature. The principal phospholipid components of the four psychrophilic vibrios were phosphatidylserine, phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. Lyso-phosphatidylethanolamine and 2 unknown phospholipids were additionally found inVibrio AF-1. The most profound effect of temperature on the phospholipid composition of these organisms was the marked increase in the total quantities synthesized at 0°C. At 15°C phosphatidylglycerol accumulated in the isolates as diphosphatidylglycerol levels decreased. Additionally inVibrio BM-2 andVibro BM-4 phosphatidylserine accumulates as phosphatidylethanolamine biosynthesis was similarly impaired. The observed changes in fatty acid and phospholipid composition in these organisms at 0°C may explain how solute transport is maintained at low temperature.Abbreviations PS
Phosphatidylserine
- PE
phosphatidylethanolamine
- PG
phosphatidylglycerol
- DPG
diphosphatidylglycerol
- lyso PE
lysophosphatidylethanolamine 相似文献
16.
Cleverson D. Souza Oral A. Evanson Douglas J. Weiss 《Microbes and infection / Institut Pasteur》2007,9(14-15):1545
We compared the kinetics of activation and antimicrobial activities of MAPK-p38 and MAPK-ERK in bovine monocytes infected with Mycobacterium avium subsp. paratuberculosis (MAP) and Mycobacterium avium subsp. avium (Maa). Monocytes were incubated with MAP or Maa organisms with or without a specific inhibitor of the MAPK-p38 pathway (SB203580), and MAPK phosphorylation and antimicrobial functions of monocytes were evaluated. At early time points MAPK-p38 phosphorylation was greater in MAP-infected bovine monocytes than in Maa-infected monocytes. At later time points MAPK-p38 phosphorylation by both organisms was similar. MAPKp38 phosphorylation in MAP-infected monocytes was similar to negative control cells, whereas in Maa-infected this activation remained greater than negative control cells. Increase phosphorylation MAPK-ERK was similar at all time points for both organisms. Bovine monocytes had minimal capacity to kill MAP organisms, to acidify MAP-containing phagosomes, or to form phagolysosome. Alternatively, bovine monocytes were able to kill Maa organisms. Addition of SB203580 to monocyte cultures increased phagosome acidification, phagolysosome formation, and killing of MAP and Maa organisms. Taken together these data indicate that early transient activation of MAPK-p38 in bovine mononuclear phagocytes by MAP organisms may be a key mechanism involved in the capacity of MAP to survive in bovine monocytes. 相似文献
17.
Nakahara Y Watanabe M Fujita A Kanamori Y Tanaka D Iwata K Furuki T Sakurai M Kikawada T Okuda T 《Journal of insect physiology》2008,54(8):1220-1225
Strategies to combat desiccation are critical for organisms living in arid and semi-arid areas. Larvae of the Australian chironomid Paraborniella tonnoiri resist desiccation by reducing water loss. In contrast, larvae of the African species Polypedilum vanderplanki can withstand almost complete dehydration, referred to as anhydrobiosis. For successful anhydrobiosis, the dehydration rate of P. vanderplanki larvae has to be controlled. Here, we desiccated larvae by exposing them to different drying regimes, each progressing from high to low relative humidity, and examined survival after rehydration. In larvae of P. vanderplanki, reactions following desiccation can be categorized as follows: (I) no recovery at all (direct death), (II) dying by unrepairable damages after rehydration (delayed death), and (III) full recovery (successful anhydrobiosis). Initial conditions of desiccation severely affected survival following rehydration, i.e. P. vanderplanki preferred 100% relative humidity where body water content decreased slightly. In subsequent conditions, unfavorable dehydration rate, such as more than 0.7 mg water lost per day, resulted in markedly decreased survival rate of rehydrated larvae. Slow dehydration may be required for the synthesis and distribution of essential molecules for anhydrobiosis. Larvae desiccated at or above maximum tolerable rates sometimes showed temporary recovery but died soon after. 相似文献
18.
Spatial and temporal patterns of morel fruiting 总被引:2,自引:0,他引:2
The biotic and abiotic factors conditioning morel fruit body production are incompletely known. We examined spatial and temporal patterns of Morchella esculenta fruiting over five years in a wooded site in Missouri, USA. Fruiting onset was inversely correlated with spring air and soil temperatures, whereas abundance was positively correlated with rain events (>10 mm) during the 30 d preceding fruiting. The two years with the greatest fruiting had the shortest fruiting seasons (6–7 d). Fruiting season length was positively correlated with soil warming, suggesting that a narrow range of optimum soil temperatures favour the explosive production of fruit bodies. All woody stems of at least 1 cm diam were mapped and stem diameter and crown condition were noted. Morel fruit bodies were significantly closer to stems of Carya spp., Tilia americana and Ulmus americana than predicted by the frequencies of these woody species or their contribution to the total basal area on the site. Although intra-annual clustering of fruit bodies was often observed, inter-annual clustering was not. The spatial pattern of M. esculenta fruiting appears to be associated with vegetation pattern, whereas the onset and abundance of fruiting are determined by the interaction of spring temperatures with availability of supporting precipitation. 相似文献
19.
Barry DP Beaman BL 《Apoptosis : an international journal on programmed cell death》2006,11(10):1695-1707
Apoptosis, or programmed cell death, is normally responsible for the orderly elimination of aged or damaged cells, and is
a necessary part of the homeostasis and development of multicellular organisms. Some pathogenic bacteria can disrupt this
process by triggering excess apoptosis or by preventing it when appropriate. Either event can lead to disease. There has been
extensive research into the modulation of host cell death by microorganisms, and several reviews have been published on the
phenomenon. Rather than covering the entire field, this review focuses on the dysregulation of host cell apoptosis by members
of the order Actinomycetales, containing the genera Corynebacterium, Mycobacterium, Rhodococcus, and Nocardia. 相似文献
20.
Baweja RB Zaman MS Mattoo AR Sharma K Tripathi V Aggarwal A Dubey GP Kurupati RK Ganguli M Chaudhury NK Sen S Das TK Gade WN Singh Y 《Archives of microbiology》2008,189(1):71-79
Bacillus anthracis makes highly stable, heat-resistant spores which remain viable for decades. Effect of various stress conditions on sporulation
in B. anthracis was studied in nutrient-deprived and sporulation medium adjusted to various pH and temperatures. The results revealed that
sporulation efficiency was dependent on conditions prevailing during sporulation. Sporulation occurred earlier in culture
sporulating at alkaline pH or in PBS than control. Spores formed in PBS were highly sensitive towards spore denaturants whereas,
those formed at 45°C were highly resistant. The decimal reduction time (D-10 time) of the spores formed at 45°C by wet heat,
2 M HCl, 2 M NaOH and 2 M H2O2 was higher than the respective D-10 time for the spores formed in PBS. The dipicolinic acid (DPA) content and germination
efficiency was highest in spores formed at 45°C. Since DPA is related to spore sensitivity towards heat and chemicals, the
increased DPA content of spores prepared at 45°C may be responsible for increased resistance to wet heat and other denaturants.
The size of spores formed at 45°C was smallest amongst all. The study reveals that temperature, pH and nutrient availability
during sporulation affect properties of B. anthracis spores. 相似文献