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1.
为探究不同食物及食物密度对盐蚕豆虫(Fabrea salina)种群动力学的影响。本文采用商业酵母和杜氏藻(Dunaliella salina)两种不同类型的饲料喂食盐蚕豆虫,探究其种群动力学特征。结果表明,杜氏藻组的盐蚕豆虫具有较高的生长率[(0.78 ± 0.019)/d]、较低的世代时间[(0.89 ± 0.021)d],内禀生长率为1.49/d,米氏常数值为1 121.32;商业酵母组生长率较低[(0.36 ± 0.001)/d],世代时间较长[(1.93 ± 0.007)d],内禀生长率为0.51/d,米氏常数值为2.68。One-way ANOVA检验结果表明,食物及食物密度对盐蚕豆虫的种群生长均有极显著影响(P < 0.01)。以密度为10 × 109 cells/L的杜氏藻投喂,可在短时间内实现盐蚕豆虫的高密度培养和利用,而酵母适用于实验室中盐蚕豆虫的保种工作。  相似文献   

2.
Immunofluorescence was used to reveal the presence of a rhodopsin-like molecule on the plasma membrane of the photoresponsive ciliate Fabrea salina. The ciliate, fixed on a glass support, showed a spontaneous red-orange fluorescence. Cells incubated with a fluoresceinated, anti-bovine opsin, sheep polyclonal antiserum showed instead a green fluorescence typical of fluorochrome excited at 436 nm, whereas cells incubated with a fluoresceinated, nonimmune sheep serum kept their original red fluorescence. Excess bovine opsin did not inhibit the antibody reaction, but detergent-coated purified bovine opsin was proven able to bind to the cell membrane. Since rhodopsin belongs to a gene-related protein family, which includes adrenergic or cholinergic receptors, the cell response to acute exposure to muscarinic and adrenergic agonist and antagonist drugs was investigated. Acetylcholine, atropine, hexamethonium, noradrenaline, or phenoxybenzamine in the culture medium (10-4 M) did not influence motion behaviour nor phototaxis of Fabrea salina. These findings raise the possibility that a rhodopsin-like molecule is present on the surface of Fabrea salina. Nevertheless, they do not prove that this surface antigen is a rhodopsin, or that this molecule is responsible for photoresponsiveness in this organism.  相似文献   

3.
ABSTRACT. Forty-five axenically grown algal (sensu lato) species representing six divisions—that is. 13 Chlorophyceae, 14 Chrysophycophyta, five Dinophycophyta, seven Cryptophycophyta, two Rhodophycophyta, and four Cyanochloronta—were aseplicaily presented separately as potential food sources to the marine helerotrich ciliate Fabrea salina under standardized algal number, medium, lighting, and temperature. The algae can be placed into three groups based on their effect on the intrinsic growth rate of the ciliate. Nutritious: Rhodomonas lens, cryptomonad LIS1, Dunaliella parva, Prasinodadus marinus, Chroomonas salina, D. tertiolecta, Chaeloceros galvestonensis, D. primolecta, Phaeodactylum tricornutum, D. salina, Isochrysis galbana, Cylindrothecaclosterium, cryptomonad strains M2, WH2 & FSA, Chroomonas sp., P. lubricus, and Peridinium trochoideum. Maintamers: Cyanobacterium strain Tigriopus blue green, P. triquetum. Monochrysis lutheri, Exuviella gracilis, Platymonas tetrathele. Cyclotella caspa, Crypthecodinium cohnii, Prasinocladus C5 strain, D. viridis, Nannochloris occulata, Tetraselmis gracilis, Anacystis marinum, Rhodosorus marinum, and Thalassiosira pseudonana. Nonnutritious: Stichococcus immobilis, Hymenomonas sp. strain 150, Syracosphaera sp. strain 181, Tetraselmis verrucosa, Thalassiosira fluviatilis, Microcoleus chthonoplastes, Synechococcus sp., Pavlova gyrans, Prymnesium parvum, Coccolithus huxleyi, Olisthodiscus luteus, Amphidinium carterii, and Porphyridium aerugineum. There was no apparent relationship between a given taxon and the nutritional value of the group, with the possible exception of the Cryptophycophyta.  相似文献   

4.
ABSTRACT. The composition and incorporation of lipids in two marine ciliates, Pleuronema sp. and Fabrea salina, was examined following growth on either an algal or bacterial diet. When allowed to feed on a natural bacterial community, Pleuronema sp. synthesized the triterpenoid alcohol gammaceran-3β-ol (tetrahymanol) and two hopanoids (hopan-3β-ol and one uncharacterized hopanoid). When fed the marine alga Isochrysis galbana, F. salina contained the major algal sterol 24-methylcholesta-5, 22-dien-3β-ol and several long chain ketones specific to the alga. In both ciliates, fatty acids composition showed a general correspondence to that of the diet. Using a series of antibiotic treatments to alter the bacterial prey community, and thus fatty acid composition of the ciliate's diet, promoted changes in the fatty acid composition of Pleuronema sp. to resemble that of the bacterial prey. The addition of a mixture of algal sterols to a bacterized culture of another scuticociliate, Parauronema acutum, inhibited tetrahymanol synthesis and resulted in the incorporation of sterols into the ciliate.  相似文献   

5.
Fuente de Piedra saline lake is located in an endorheic basin in the south of Spain. This lake is very shallow (0.5 m max. depth during 1987–88) and relatively large (± 1350 ha). It is a temporary playa lake, showing irregular cycles, with frequent seasonal drought and a high degree of unpredictability. The lake was sampled monthly during a relatively rainy year (1987–88, 10.5 months permanence). The result of combined analyses for environmental variables (salinity, temperature and soluble inorganic forms of nitrogen and phosphorus), variables related to biological activity (chlorophyll a, sediment organic matter and redox potential) and the direct analysis of the planktonic community, shows the existence of two periods of dominance by autotrophs. The first occurs during winter, exhibits a progressively higher surface to volume ratio for phytoplankton and is followed in the spring by high zooplankton densities (Moina salina, Fabrea salina) and very low phytoplankton densities, suggesting the existence of a period with a detritus-based food web. The summer period coincides with a community better adapted to high salinities that is dominated by Dunaliella salina, D. viridis, diatoms and the ciliate Fabrea salina, and associated with high ammonium concentrations. A new period of organic matter accumulation could be facilitated, in the last moments before the lake dries, by a progressive decrease in zooplankton abundance.  相似文献   

6.
E. Michels  L. De Meester 《Hydrobiologia》1998,379(1-3):199-206
We examined the influence of food quality on the phototactic behaviour of Daphnia magna. Cohorts of a positively phototactic D. magna clone were fed nine diets differing in quality. Diets were obtained by substitution of a fraction of unicellular algae ( Scenedesmus acutus) by a biomass-equivalent of fresh yeast ( Saccharomyces cerevisiae). Some of the diets were enriched with an inoculum of ciliates and organic compounds added as a hay infusion filtrate. Animals fed with a diet containing at least 25% algae showed a similar phototactic behaviour as animals fed with a diet that contained 100% algae. Addition of ciliates to the yeast diets resulted in a lower mortality and a higher reproductive rate compared to diets without a ciliate supplement. The presence of ciliates did not influence phototactic behaviour. Experiments testing for a maternal effect showed that the phototactic behaviour of the animals was strongly influenced by diet during the early developmental stages, but was not influenced by the diet of the mother. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

7.
Abstract Size-selective grazing by Cyclidium sp., isolated as a dominant ciliate bacterivore from the Římov Reservoir (South Bohemia), was examined using fluorescent labelled bacteria (FLB) produced from natural bacterioplankton or pure bacterial cultures. Sizes of ingested bacteria in food vacuoles were measured directly. Three experimental arrangements were used: (1) Ciliates were grown on the pure culture of Alcaligenes xylosoxidans and fed with various proportions of ‘large’ and ‘small’ FLB (mean biovolume, 0.377 and 0.202 μm3, respectively) prepared from the same bacterial species. Results clearly showed significant selection of larger bacteria. (2) Ciliates were grown on natural bacterioplankton from the reservoir and subsequently fed on FLB prepared from the reservoir bacterioplankton (mean biovolume, 0.065 μm3). Independent of either prey or predator abundance, larger FLB (> 0.100 μ m3, and especially those > 0.200 μ m3) were ingested with much higher frequency than their occurrence i the natural assemblage. (3) Ciliates were grown on the reservoir baterioplankton and fed by FLB prepared from the culture of Pseudomonas sp. In contrast with previous results, no size selection of the ciliate was found when FLB were different from the bacterial food used to grow the ciliate. Ecological impacts of size-selective bacterivory are suggested.  相似文献   

8.
The unicellular green alga Dunaliella salina is a halotolerant eukaryotic organism. Its halophytic properties provide an important advantage for open pond mass cultivation, since D. salina can be grown selectively. D. salina was originally described by E. C. Teodoresco in 1905. Since that time, numerous isolates of D. salina have been identified from hypersaline environments on different continents. The new Dunaliella strain used for this study was isolated from the salt farm area of the west coastal side of South Korea. Cells of the new strain were approximately oval- or pear-shaped (approximately 16-24 microm long and 10-15 microm wide), and contained one pyrenoid, cytoplasmatic granules, and no visible eyespot. Although levels of beta-carotene per cell were relatively low in cells grown at salinities between 0.5 to 2.5 M NaCl, cells grown at 4.5 M NaCl contained about a ten-fold increase in cellular levels of beta-carotene, which demonstrated that cells of the new Korean strain of Dunaliella can overaccumulate beta- carotene in response to salt stress. Analysis of the ITS1 and ITS2 regions of the new Korean isolate showed that it is in the same clade as D. salina. Consequently, based on comparative cell morphology, biochemistry, and molecular phylogeny, the new Dunaliella isolate from South Korea was classified as D. salina KCTC10654BP.  相似文献   

9.
Fertilized eggs from an spontaneously spawn of thirty sexually mature sea urchins (Arbacia punctulata) were incubated to complete embryonic development. The echinopluteus larvae (3 ind/ml) were distributed into 50 plastic containers (25 containers at 30 psu and 25 containers at 40 psu) and fed on Tetraselmis chuii, Nannochloropsis oculata, Isochrysis galbana, Chaetoceros gracilis and C. calcitrans under a natural photoperiod. The water of the containers was partially renewed (75%) everyday. Larval anatomic development aspects, daily survival and growth were determined. The growth was determined through postoral arms and body length measurement, and body diameter of twelve larvae during metamorphosis. During the planktonic larval phase, only the I. galbana diet produced similar results for both salinities. The relative growth of larvae was isometric (I) for larvae fed on I. galbana at two salinities and positive allometric for those fed on C. gracilis and C. calcitrans at both salinities. In this study A. punctulata started metamorphosis at day 14 and was completed 30 days after fecundation. Significant differences were detected in post-settlement body growth between the two salinities (F = 23.58, p < 0.05): growth was better for larvae at 30 psu (final body diameter was 3.14 +/- 0.44 mm). The final rate of planktonic larvae was highest with I. galbana (58.33%). For juveniles the rate was 6.48% for those fed on C. gracilis (40 psu in both larvae and juveniles). We recommend the use of this diet and 40 psu for survival or 30 psu for growth.  相似文献   

10.
The biochemical composition and abundance variation of zooplankton (copepods and Artemia salina) were determined in four ponds of increasing salinity (A5, A16, C41 and M2) in the Sfax solar saltern (Tunisia). The zooplankton community was dominated by copepods in the ponds A5, A16 and C41. The pond M2 was marked by the presence of only Artemia salina. Our results showed the dominance of total saturated fatty acids (SFA), which made up 57%–95% of total fatty acids (TFA). SFA 16:0 and 18:0 dominate in all ponds. A. salina showed the highest amounts of the total monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), this indicates that this species could be employed in hatcheries and used as food source for some aquarium species. Fatty acids of herbivory, proportion of all diatom markers to all flagellate markers (D/F), were negatively correlated with the total zooplankton (r = −0.998, p < 0.05). A. salina was negatively correlated with a biomarker for carnivory polyunsaturated fatty acids/saturated fatty acids (PUFA/SFA) (r = −0.959, p < 0.05). The dietary quality of zooplankton seems to be dependent on food availability in the four studied ponds.  相似文献   

11.
Reproduction, feeding and population structure were investigated in the mountain mullet, Agonostomus monticola, in eastern Jamaica between 1982 and 1986. Female fishes just outnumbered males 1.2 : 1. Minimum size at maturity for females was 123 mm fork length (FL) and 96 mm FL for males. Mean size at maturity for females was 165.8 mm FL (S.D.=1.61) and for males was 148.4 mm FL (S.D.=2.97). Fecundity was 340 000 eggs for a 25 g ovary. Fecundity (F) was related to size by the equation F=153.8 FL1.36. Mean lengths of males and females captured by all methods were 129.4 mm (S.D.=5.56) and 160.4 mm FL (S.D.=0.70), respectively. A. monticola was found to be chiefly an insectivorous feeder. The major food items found in stomach contents in ranked sequence were insects, freshwater prawns, plant detritus and algae.  相似文献   

12.
The seasonal distribution of metazooplankton and large-sized ciliates was studied in four ponds of different salinity in the solar salterns of Sfax (Tunisia). Total zooplankton abundance varied from 1 × 103 to 4.7 × 106 ind m–3. Salinity had a negative effect on the abundance of copepods and rotifers which were absent in the pond with the highest salt concentration (180) in which the number of taxa was low and Artemia or the ciliate Fabrea largely dominated the zooplankton community. Temperature and the presence of Dunaliella salina as prey appeared as key factors in controlling the abundance of Artemia, while organic detritus appeared as important in the diet of Fabrea. Change in zooplankton species composition along the hypersaline gradient (40–90) was primarily related to salinity. However, our data suggest the importance of both the abundance and composition of food in the spatial and temporal variations of some zooplankton species.  相似文献   

13.
目的:研究以活酵母为输送载体的狂犬病疫苗对小鼠的免疫保护能力和免疫疗程。方法:小鼠首先灌食高浓度空白活酵母INVSI,并于灌胃后8h和12h分别采集小鼠空肠和回肠组织并提取小肠浸出液培养,计算活酵母经肠胃环境后的存活率;分别取狂犬病糖蛋白(glycoprotein,G)分泌型表达菌株pYes-InG和胞内表达型菌株pYes-G灌胃小鼠,灌胃结束后12h采集小鼠血清和小肠组织,采用免疫组织化学方法检测抗原物质G在小肠上皮细胞的分布,采用ELISA检测小鼠血清中和性抗体的滴度。结果:活酵母经灌食消化8h后在小肠中的存活率最高达36.11%,12h后降至0.59%;口服分泌型pYes-InG重组酵母的小鼠小肠组织和血清中能检测到抗原物质G和低量的中和性抗体,ELISA分析显示,小鼠经过3~4次免疫接种,免疫效果基本恒定,而口服胞内表达型pYes-G重组酵母的小鼠小肠组织和血清中均未检测到目标物。结论:分泌型重组酵母pYes-InG经多次口服可对狂犬病起到一定的预防作用,但它诱导产生的中和性抗体浓度低,免疫应答慢,虽不适合用于控制突发性狂犬病的传染以及治疗狂犬病患者,但从免疫机制、免疫方式、安全性以及生产成本等因素考虑,仍具有良好的研究价值。  相似文献   

14.
Ecosystem functioning is affected by horizontal (within trophic groups) and vertical (across trophic levels) biodiversity. Theory predicts that the effects of vertical biodiversity depend on consumer specialization. In a microcosm experiment, we investigated ciliate consumer diversity and specialization effects on algal prey biovolume, evenness and composition, and on ciliate biovolume production. The experimental data was complemented by a process‐based model further analyzing the ecological mechanisms behind the observed diversity effects. Overall, increasing consumer diversity had no significant effect on prey biovolume or evenness. However, consumer specialization affected the prey community. Specialist consumers showed a stronger negative impact on prey biovolume and evenness than generalists. The model confirmed that this pattern was mainly driven by a single specialist with a high per capita grazing rate, consuming the two most productive prey species. When these were suppressed, the prey assemblage became dominated by a less productive species, consequently decreasing prey biovolume and evenness. Consumer diversity increased consumer biovolume, which was stronger for generalists than for specialists and highest in mixed combinations, indicating that consumer functional diversity, i.e. more diverse feeding strategies, increased resource use efficiency. Overall, our results indicate that consumer diversity effects on prey and consumers strongly depend on species‐specific growth and grazing rates, which may be at least equally important as consumer specialization in driving consumer diversity effects across trophic levels. Synthesis In a microcosm experiment, we investigated multitrophic consumer diversity and specialization effects using ciliate consumers and microalgal prey. Consumer diversity increased consumer biovolume, which was highest in combinations containing both generalists and specialists. Specialist consumers showed a stronger negative effect on prey biovolume and evenness than generalists. These experimental data were supported by a process‐based model, indicating that the large effect of the specialists was based on high per capita grazing rate on the two most productive prey species. Species‐specific traits such as growth and grazing rates were equally important for multitrophic diversity effects than consumer specialization.  相似文献   

15.
Mean apparent dry mass absorption efficiency by P. auritus fed on mealworms was 0.853 (S.D.=0.4, n=43). Mean apparent energy absorption efficiency by P. auritus and M. daubentoni fed on mealworms was 0.90 (S.D.=0.007, n=8). The mean energy content of mealworms was 28.6 kJ.g-1 dry mass (S.D.=1.1, n=8), and that of faeces was 19.5 kJ.g-1 (S.D.=0.7, n=8) in P. auritus and 19.9 kJ.g-1 (S.D.=1.3, n=8) in M. daubentoni . Water content of mealworms was 61.1% wet mass (S.D.=1.4, n=173); water content of faeces was 73.3% in P. auritus (S.D.=6.8, n=76) and 72.3% (S.D.=7.0, n=42) in M. daubentoni . Oven-dried mealworms consisted of <1% ash, <1% carbohydrate, 31% lipid and 39% protein. We suggest that the dry mass unaccounted for (28%) represented chitin, of which 59% was apparently absorbed during digestion. Apparent absorption by mass of both lipid and protein by P. auritus fed on mealworms was greater than 90%. Cumulative post-prandial defecation was sigmoidal in both bat species with 50% (by mass) of faeces being voided within 4 h and 95% within 12 h of feeding. On the basis of previous measurements, using doubly-labelled water, of daily energy expenditure and water flux in free-living P. auritus , we predict that water intake via the food, as free water and as potential metabolic water, represents 20 to 40% of total daily water flux for P. auritus during lactation in the wild.  相似文献   

16.
The suppressive effects on acute alcoholic liver injury of S-adenosylmethionine (SAM) and the sake yeast, Saccharomyces cerevisiae Kyokai No. 9, have been shown previously. To enhance the suppression of acute alcoholic liver injury by sake yeast, we prepared SAM-accumulating sake yeast (SAM yeast). Male C57BL/6 mice that had been fed on a diet containing 0.25% SAM yeast or sake yeast for two weeks received three doses of ethanol (5 g/kg BW). In the mice fed on the SAM yeast, the ethanol-induced increases in both triglyceride (TG) and alanine aminotransferase (ALT) were significantly repressed. In addition, the SAM yeast-fed mice did not show an ethanol-induced decrease in hepatic SAM level, suggesting that a disorder of methionine metabolism in the liver caused by ethanol was relieved by the SAM yeast. These results suggest that the SAM yeast had a stronger effect suppressing acute alcoholic liver injury in mice than the sake yeast.  相似文献   

17.
Cell growth of the marine microalga Isochrysis galbana was regulated by the addition of seaweed extracts in the culture medium. Methanol-soluble extracts from 27 species of seaweed showed growth activation only from Enteromorpha linza, and growth inhibition from Ishige foliacea and Sargassum sagamianum. Water-soluble extracts from Grateloupia turuturu and Monostroma nitidum showed growth activation, while none of the seaweed showed growth inhibition. From results of growth activation of extracts on I. galbana, the water extract of M. nitidum was the most effective up to two-fold increase in cell density with the addition of 1 mg mL-1 of extract to the medium. The cell growth rate was increased from 0.52 to 0.65 d-1. Cell size, gross biochemical compositions, fatty acid compositions, and digestion efficiency by shellfish differed marginally between cultures of I. galbana grown with and without the M. nitidum aqueous extract. This extract has also enhanced the growth of other feed microalgae tested, including Dunaliella salina. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

18.
食物条件对日本蟳幼体存活与变态的影响   总被引:6,自引:0,他引:6  
This paper studied the effects of different kind and density of baits and different starvation duration on Charybdis japonica larvae. The results showed that the preferable baits of zoaea-1 were Chaetoceros sp. and Isochysisgalbana, and their proper feeding density were 20 × 10^4 cell· ml^-1. The preferable bait of the larvae after zoaea-1 was Artemia salina nauplius, and its proper feeding density for zoaea-2 and zoaea-3 was 2 - 3 ind· ml^-1. The point of no-return for zoaea-1 of Charybdisjapoptica was about 66 hours. 18 hours starvation did not affect the growth of the larvae, but their livability would be decreased, and their metamorphism would be suspended along with the starvation duration.  相似文献   

19.
This study investigated the regulation of the major light harvesting chlorophyll a/b protein (LHCII) phosphorylation in Dunaliella salina thylakoid membranes. We found that both light and NaCl could induce LHCII phosphorylation in D. salina thylakoid membranes. Treatments with oxidants (ferredoxin and NADP) or photosynthetic electron flow inhibitors (DCMU, DBMIB, and stigmatellin) inhibited LHCII phosphorylation induced by light but not that induced by NaCl. Furthermore, neither addition of CuCl(2), an inhibitor of cytochrome b(6)f complex reduction, nor oxidizing treatment with ferricyanide inhibited light- or NaCl-induced LHCII phosphorylation, and both salts even induced LHCII phosphorylation in dark-adapted D. salina thylakoid membranes as other salts did. Together, these results indicate that the redox state of the cytochrome b(6)f complex is likely involved in light- but not salt-induced LHCII phosphorylation in D. salina thylakoid membranes.  相似文献   

20.
The competition between Cephalonomia stephanoderis and Prorops nasuta was studied in the laboratory, using coffee fruits infested with the host of these parasitoids, the coffee berry borer Hypothenemus hampei . Experiments were performed under different conditions, using: (a) three temperatures; (b) five densities of infested coffee fruits; and (c) introducing the parasitoids at different times. The effect of competition was determined according to the production of the progeny. When cultured together at the same time, C. stephanoderis produced in general, more progeny than P. nasuta under conditions of 29°C and alternating temperatures of 18–29°C. Nevertheless, there were significant differences at densities of 1 : 3, fruits : parasitoids ( F 0.05=8.9; d.f.=1, 12; P < 0.05) and 1 : 5 ( F 0.05=7.56; d.f.=1, 12; P < 0.05) at 29°C. Under alternating temperatures, there were differences at the same ratios as above in favour of C. stephanoderis , 1 : 3 ( F 0.05=20.08; d.f.=1, 12; P < 0.05) and 1 : 5 ( F 0.05=20.21; d.f.=1, 12; P < 0.05). Prorops nasuta was clearly more successful in all densities at 18°C. When C. stephanoderis was introduced 10 days before P. nasuta , the progeny production was markedly higher in eight from 10 densities at temperatures of 29°C and 18–29°C. Despite being introduced 10 days later, P. nasuta showed better performance at 18°C. When P. nasuta was introduced 10 days earlier than C. stephanoderis , there were significant differences in progeny production in favour of P. nasuta in 13 of 15 fruit densities under the three temperatures. Both parasitoids avoided ovipositing on previously parasitized hosts. Aggressive behaviour or interference was not observed when they were outside coffee fruits.  相似文献   

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