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1.
Cell suspension cultures of Gymnema sylvestre treated with four different elicitors, methyl jasmonate (MJ), yeast extract, chitin and pectin were studied for the production of gymnemic acid as gymnemagenin equivalent, that was analyzed by high performance liquid chromatography (HPLC). All the four tested elicitors induced gymnemic acid production in cell suspension cultures. Highest gymnemic acid content was achieved following treatment with yeast extract (100.47 ± 0.28 mg/l), this was followed by MJ (70.43 ± 0.26 mg/l), pectin (64.19 ± 0.23 mg/l) and chitin (62.72 ± 0.13 mg/l). The addition of elicitors has shown a significant influence on cell growth that affected cell growth compared to respective controls. The highest gymnemic acid production was obtained after 20 days of elicitation in cultures treated with 0.5 g l−l yeast extract, it was 5.25-folds greater than in control. These results suggest that the addition of an elicitor to Gymnema sylvestre cell suspension cultures could stimulate and enhance gymnemic acid production. In our present study we could able to overproduce gymnemic acid up to 51.97 ± 0.26 mg l−l (dry weight basis) in yeast extract treated cell suspension cultures.  相似文献   

2.
The tiger shrimp (Penaeus monodon) is an important marine crustacean in terms of biological diversity and aquaculture resource. The shrimp is widespread across the Indo‐Pacific region and shows apparent genetic differentiation among geographical populations. It is common practice to transport female brooders between different countries to seed the shrimp farms, posing potential problems of unwanted population admixture. We developed 23 polymorphic microsatellites for P. monodon (average HE = 0.936) and these microsatellites were applicable for studying population differentiation, identifying valid stocks and tagging nonindigenous farmed shrimps.  相似文献   

3.
Bioethanol is an attractive alternative to fossil fuels. Saccharomyces cerevisiae is the most important ethanol producer. However, yeast cells are challenged by various environmental stresses during the industrial process of ethanol production. The robustness under heat, acetic acid, and furfural stresses was improved for ethanologenic S. cerevisiae in this work using genome shuffling. Recombinant yeast strain R32 could grow at 45°C, and resist 0.55% (v/v) acetic acid and 0.3% (v/v) furfural at 40°C. When ethanol fermentation was conducted at temperatures ranging from 30 to 42°C, recombinant strain R32 always gave high ethanol production. After 42 h of fermentation at 42°C, 187.6 ± 1.4 g/l glucose was utilized by recombinant strain R32 to produce 81.4 ± 2.7 g/l ethanol, which were respectively 3.4 and 4.1 times those of CE25. After 36 h of fermentation at 40°C with 0.5% (v/v) acetic acid, 194.4 ± 1.2 g/l glucose in the medium was utilized by recombinant strain R32 to produce 84.2 ± 4.6 g/l of ethanol. The extent of glucose utilization and ethanol concentration of recombinant strain R32 were 6.3 and 7.9 times those of strain CE25. The ethanol concentration produced by recombinant strain R32 was 8.9 times that of strain CE25 after fermentation for 48 h under 0.2% (v/v) furfural stress at 40°C. The strong physiological robustness and fitness of yeast strain R32 support its potential application for industrial production of bioethanol from renewable resources such as lignocelluloses.  相似文献   

4.
The thalassinidean shrimp Callichirus seilacheri is a common species in the intertidal zone of the South American Pacific coast. However, our knowledge of its reproductive ecology is rather limited. The present study was carried out between January and December 2003 at Las Machas, northern Chile. Although ovigerous females were encountered almost throughout the study period, they were particularly abundant between May and September when water temperatures were lowest and sediment coverage of the burrow entrances was highest. Females of C. seilacheri produced numerous (17,450 ± 3,796 eggs) and small (0.884 ± 0.080 mm; 0.262 ± 0.054 mm3) eggs when compared to other thalassinidean shrimps for which such information is available. Fecundity was positively correlated with female size; however, correlations were allometric, which might be related to the elasticity of the abdomen. Egg volume increased by 41.2% during embryogenesis, and egg loss during the incubation period was on average 8%. Females inverted on average 14.9% of their dry weight into egg production.  相似文献   

5.
Methyl jasmonate, 50 μM, 0.5 mg yeast extract/l and 100 mg chitosan/l stimulated plumbagin production in Drosera burmanii whole plant cultures after 6 days of elicitation. Yeast extract (0.5 mg/l) was the most efficient enhancing plumbagin production in roots of D. burmanii to 8.8 ± 0.5 mg/g dry wt that was 3.5-fold higher than control plants.  相似文献   

6.
A novel anamorphic yeast strain, A1-01T, belonging to the genus Rhodotorula was isolated from a plant in Taiwan and analysed morphologically, physiologically and phylogenetically. Neither ballistoconidia nor sexual reproduction was observed. Sequence analysis of the 26S rRNA gene and the ITS region indicate that Rhodosporidium sphaerocarpum is the most closely related species, with 14 and 24 nucleotide substitutions, respectively. The novel species differed physiologically from R. sphaerocarpum in its ability to assimilate ethylamine and cadaverine, its inability to assimilate ethanol and nitrite. From these comparative analyses, the following novel yeast species is proposed: Rhodotorula taiwanensis sp. nov. with the type strain of A1-01T (BCRC 23118T = CBS 11729T).  相似文献   

7.
A probiotic bacterium isolated from the gut of wild shrimp Penaeus monodon rendered maximum antagonistic activity against shrimp pathogens and was capable of producing extracellular enzymes. The probiotic bacterium was identified as Bacillus cereus through 16S rRNA sequencing. The lyophilized B. cereus was supplemented with shrimp basal diet at four different concentrations (0.1–0.4%/100 g feed) in D1–D4 diets. The viability of probiotic bacterium in the test diets was evaluated during the study period at various time intervals. The viability ranged from 50.24 ± 1.42 to 180.34 ± 1.30 CFU/g in D1 to D3 diets on the 30th day, whereas it was slightly declined from 45.23 ± 1.30 to 169.13 ± 1.18 CFU/g during the 90th day of storage. A control diet (C), devoid of probiotic supplementation was also simultaneously prepared. During experimentation, P. monodon postlarvae (PL-15) were cultured in individual one tonne capacity FRP tanks in triplicates provided with equal amount of substratum (clay soil) and fed with these respective diets at ad libitum for 90 days. Survival was high (82.0 ± 1.60%) in D4 diet fed shrimp as against a low survival of 65.0 ± 1.33% displayed by control diet fed shrimp. Overall growth responses inferred that a maximum production of 10.45 ± 0.275 g, SGR of 4.40 ± 0.179% and a better FCR of 1.27 ± 0.081 were obtained in D4 diet fed shrimp. However, the water quality parameters showed nonsignificant (P > 0.05) variations among the control and the probiotic treated groups. The tested immunological parameters such as Total haemocyte count, phenoloxidase activity, respiratory burst activity, lysozyme activity, plasma protein concentration and bactericidal activity were higher in D4 diet fed P. monodon, when compared to that of other diets fed shrimp. It is therefore suggested that lyophilized probiotic B. cereus at a concentration of 0.4%/100 g feed was efficient in stimulating the growth and immunity in shrimp.  相似文献   

8.
In order to explore compounds naturallly inhibitory to shrimp pathogenic vibrios, a culture filtrate of Pseudomonas sp. W3 at a pH of 2 was extracted with ethyl acetate (EtOAc) to produce 82.15 mg/l of a yellow–brown extract (EtOAc-W3) that had MIC values of 225-450 μg/ml against the growth of 18 shrimp pathogenic Vibrio harveyi strains. The MIC of EtOAc-W3 against the most pathogenic strain PSU 2015 was 450 μg/ml and this strain had the lowest LD50 (50% lethal dose) to pacific white shrimp (Litopenaeus vannamei, PL 21). At this MIC value, EtOAc-W3 in artificial sea water (ASW) killed strain PSU 2015; however in natural sea water, only a partial growth inhibition was observed. The toxicity to pacific white shrimp and antivibrio activity of the EtOAc-W3 were investigated by conducting an experiment with 4 sets; native control (commercial ASW), EtOAc-W3 control (MIC/10, 45 μg/ml), challenge (inoculation 6.0 × 106 c.f.u./ml PSU 2015) and treatment (6.0 × 106 c.f.u./ml PSU 2015 + 45 μg/ml EtOAc-W3). The same experiment was repeated by increasing the dose of EtOAc-W3 to 90 μg/ml (MIC/5). Both concentrations of EtOAc-W3 tested had no toxicity to postlarval shrimps. A significant decrease in shrimp mortality was observed over a 72 h period as approximately 80% of the shrimps died in each challenge set but only 63 and 23% died in the presence of 45 and 90 μg/ml EtOAc-W3. The major component of EtOAc-W3 was supposed to be 2-heptyl-4-quinolone (HHQ) by FAB-MS and 1H-NMR analyses of the purified fraction.  相似文献   

9.
Aims: To investigate the antimicrobial spectrum of Lactococcus piscium CNCM I‐4031 and its protective effect in cooked and peeled shrimp against Brochothrix thermosphacta. Methods and Results: Sixteen pathogenic and spoiling bacteria were inhibited in Elliker, but not in shrimp juice agar plates. In shrimp packed under modified atmosphere and stored at 8°C, B. thermosphacta (103 CFU g?1) was inhibited by 4·1 log CFU g?1 when co‐inoculated with L. piscium (106 CFU g?1). Brochothrix thermosphacta spoiled the product after 11 days, with the emission of strong butter/caramel off‐odours. In co‐culture with L. piscium, sensory shelf‐life was extended by at least 10 days. The inhibition was partially explained by a drop in pH from 6·6 to 5·6. The physicochemical composition of shrimp and shrimp juice was established to identify the inhibition mechanisms involved. Conclusion: Lactococcus piscium CNCM I‐4031 has a wide antimicrobial spectrum. The strain inhibits B. thermosphacta in shrimp and significantly prolongs sensory shelf‐life. Significance and Impact of the Study: Lactococcus piscium CNCM I‐4031 is shown to be a promising agent for improving shrimp quality and may be tested against pathogens and in other food matrices. Knowledge of the physicochemical composition of shrimp and shrimp juice will allow the development of a chemically defined model medium for determining the inhibition mechanisms involved.  相似文献   

10.
The antagonistic effects of Lactobacillus against pathogenic bacteria were evaluated in vitro on cultured Caco-2 cells. Lactobacilli were added simultaneously with enteric pathogenic strains (enterotoxigenic Escherichia coli K88 or Salmonella typhimurium SARB21 and SL1344), before pathogenic strains and after pathogenic strains for competition, exclusion and displacement assays. The six lactobacilli significantly limited the adhesion and invasion of the pathogenic bacteria. In the simulating competition and exclusion assays, the adhesion of pathogenic strains was reduced by Lactobacillus strains significantly, whereas the inhibiting effect on pathogenic strains adhesion was a little weaker in the displacement assay. Furthermore, we found that the antagonistic effects of lactobacilli against K88, SARB21, and SL1344 were various. Strain R4 showed a strong inhibitory effect on the adhesion of K88 to Caco-2 cells. In the competition assay of R4, the number of viable cell-associated K88 (3.84 ± 0.10 log CFU/well) was much lower than the control group without Lactobacillus (5.98 ± 0.02 log CFU/well). Compared to the control group (6.07 ± 0.02 log CFU/well), the six Lactobacillus strains all performed strong antagonistic effects against SL1344, particularly D17 showed a higher inhibitory effect in the displacement assays (4.15 ± 0.04 log CFU/well). These results implied that several Lactobacillus strains might be useful for protecting against enteric pathogenic infection.  相似文献   

11.
Studies were carried out to utilize in situ proteases of shrimp heads to recover carotenoproteins possessing antioxidant activity. Highest protease activity of the buffer extract was found at pH 8.0 (9.85 ± 0.61 units). The protease activity increased with temperature up to 50°C and reduced thereafter with highest activity being 19.32 ± 2.0 units. Thus, the autolysis of shrimp heads for recovery of carotenoprotein was carried out at pH 8.0 and at 50°C. Waste to buffer ratio had a significant (p < 0.05) effect on recovery of carotenoids in carotenoprotein filtrate with a maximum of 58.5 ± 6.4% recovery with a waste to buffer ratio of 1:2.5 (w:v). The carotenoid recovery increased significantly to 63.4% ± 3.6% at the end of a 4-h autolysis. The studies on combined effect of waste to buffer ratio and autolysis time indicated increase in protein recovery with increase in waste to buffer ratio but not with autolysis time. DPPH scavenging activity of the carotenoprotein isolate increased with autolysis time up to 100 min, and thereafter, reduced above 160 min of autolysis time. With increase in waste to buffer ratio, the scavenging activity increased, reaching more than 12.5 mg TBHQ equivalent/mg protein at waste to buffer ratio of 1:5. The optimum autolysis condition for obtaining antioxidant activity rich carotenoprotein from shrimp heads was found to be waste to buffer (pH 8.0) ratio of 1:5 and an autolysis time of 2 h at 50°C. The isolated carotenoprotein was found to have antioxidant activity with respect to singlet oxygen quenching, reducing power and metal chelating activity.  相似文献   

12.
This study describes in vitro shoot induction and plant regeneration from a mature apical meristem and nodal explants of the endangered medicinal shrub Vitex agnus-castus. Multiple shoots were induced directly from the axis of nodal and apical meristem explants on Murashige and Skoog (MS) medium containing 3% sucrose and different concentrations (1.0, 1.5, 2.0, and 2.5 mg/l) of 6-benzyl aminopurine (BAP) in combination with Kinetin (Kin) and α-naphthalene acetic acid (NAA), both at 0.1 mg/l. BAP and Kinetin were used as supplements to MS basal medium, either individually or in combination with auxins. The optimal concentration of BAP for inducing bud break was found to be 2.0 mg/l when Kinetin was at 0.1 mg/l. Regeneration frequency was highest for both apical meristem and nodal explants (94.5% and 90.3%, respectively) when explants were cultured on MS medium supplemented with BAP (2.0 mg/l) and Kin (0.1 mg/l). A maximum of 7.7 ± 0.4 and 6.7 ± 0.2 shoots were obtained per explant for apical meristem and nodal explants, respectively. Regenerated shoots, transferred to MS medium supplemented with either 1.0 or 1.5 mg/l BAP combined with 0.1 mg/l GA3, showed maximum elongation of 6.7 ± 0.4 and 6.0 ± 1.3 cm in apical meristem and nodal explants, respectively. In vitro regenerated shoots transferred to half-strength MS medium supplemented with 0.1 mg/l IBA induced 90.4% of the shoots to form roots after 30–35 d of culture. Up to 80% of the regenerated shoots were successfully established in soil in the greenhouse.  相似文献   

13.
Cerebral blood flow (CBF) of a vespertilionid bat, Miniopterus fuliginosus (M. f.), and a pteropodid bat, Rousettus leschenaultii (R. l.) was measured non-invasively during induced hypothermia (37–10°C for M. f. and 37–24°C for R. l.) with perfusion-weighted magnetic resonance imaging. In both species, the average CBF was found to decrease with rectal temperature. The patterns of hypothermia-induced regional CBF changes, however, were different between the two species. In the pteropodid bat, the extent of CBF decrease at lower rectal temperature was similar in the cortex and thalamus, resulting in an unchanged thalamus/cortex CBF ratio. In contrast, the thalamus/cortex CBF ratio in the vespertilionid species increased progressively with decreasing rectal temperature (1.52 ± 0.14 at 37 ± 1°C vs. 2.28 ± 0.29 at 10 ± 1°C). These results suggest that the manner in which the two bat species cope with low body temperature may be reflected by a differential CBF regulation between thalamus and cortex.  相似文献   

14.
This work optimized the novel biotransformation process of 4′-demethylepipodophyllotoxin (DMEP) into 4′-demethylepipodophyllic acid (DMEPA) by Bacillus fusiformis CICC 20463. Firstly, the biotransformation process was significantly affected by medium composition. 5 g/L of yeast extract and 10 g/L of peptone were optimal for DMEPA production (i.e., 2.81 ± 0.21 mg/L), while not beneficial for the cell growth of B. fusiformis. This indicated that the biosynthesis of DMEPA was not corresponded well to the cell growth of B. fusiformis. 40 g/L of sucrose was optimal for DMEPA production (i.e., 2.94 ± 0.17 mg/L), and 3 g/L of NaCl was the best for DMEPA production (i.e., 4.10 ± 0.18 mg/L). Secondly, the production of DMEPA was significantly enhanced by the control of substrate concentration and culture pH. 100 mg/L of substrate was optimal for DMEPA production (i.e., 6.47 ± 0.35 mg/L), and DMEPA concentration was enhanced to 38.78 mg/L by controlling culture pH at 9.0 in the stirred-tank bioreactors. The fundamental information obtained in this study provides a simple and efficient way to produce DMEPA by biotransformation.  相似文献   

15.
16.
Bioconversion of biodiesel-derived crude glycerol into carotenoids and lipids was investigated by a microbial conversion of an oleaginous red yeast Sporidiobolus pararoseus KM281507. The methanol content in crude glycerol (0.5%, w/v) did not show a significant effect on biomass production by strain KM281507. However, demethanolized crude glycerol significantly supported the production of biomass (8.64?±?0.13?g/L), lipids (2.92?±?0.03?g/L), β-carotene (15.76?±?0.85?mg/L), and total carotenoids (33.67?±?1.28?mg/L). The optimal conditions suggested by central composite design were crude glycerol concentration (55.04?g/L), initial pH of medium (pH 5.63) and cultivation temperature (24.01°C). Under these conditions, the production of biomass, lipids, β-carotene, and total carotenoids were elevated up to 8.83?±?0.05, 4.00?±?0.06?g/L, 27.41?±?0.20, and 53.70?±?0.48?mg/L, respectively. Moreover, an addition of olive oil (0.5???2.0%) dramatically increased the production of biomass (14.47?±?0.15?g/L), lipids (6.40?±?0.09?g/L), β-carotene (54.43?±?0.95?mg/L), and total carotenoids (70.92?±?0.51?mg/L). The oleic acid content in lipids was also increased to 75.1% (w/w) of total fatty acids, indicating a good potential to be an alternative biodiesel feedstock. Meanwhile, the β-carotene content in total carotenoids was increased to 76.7% (w/w). Hence, strain KM281507 could be a good potential source of renewable biodiesel feedstock and natural carotenoids.  相似文献   

17.
Oral administration of polysaccharide gel (PG) in shrimp diets revealed immunostimulating potential and disease resistance in Penaeus monodon (black tiger shrimp). PG from the fruit-rind of Durio zibethinus has been characterized to be a pectic polysaccharide with immunomodulating and antibacterial activities. PG inhibited growth of the shrimp bacterial pathogen, Vibrio harveyi 1526, by agar diffusion and broth microdilution tests. Clear inhibition zones on agar plates were observed at the lowest PG concentration of 3.1 mg/ml, where minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values for PG were 6.3 and 12.5 mg/ml, respectively. Each group of juvenile shrimps, initial mean body weight 0.29 ± 0.04 g, was housed in a closed-recirculating treated water system and was fed with PG-supplemented diets containing 1, 2 and 3% PG or shrimp basal diet in the control group for 8 and 12 weeks. PG-supplemented diets did not contribute to the overall growth of black tiger shrimp. The immune response was evaluated by analysis of prophenoloxidase activity and total hemocyte count in the shrimp fed PG-supplemented diets for 12 weeks. Prophenoloxidase activity in shrimp fed the 1, 2 and 3% PG-supplemented diet and total hemocyte count in shrimp fed the 1 and 2% PG-supplemented diet were higher (P < 0.05) than those of the control group. The percent survival was higher in groups fed the 1–3% PG-supplemented diets in challenge tests with either white spot syndrome virus (WSSV) or the bacterium V. harveyi 1526 than that of the control group. Relative percent survival (RPS) values in groups fed the 2% PG-supplemented diet showed the highest RPS value for disease resistance of 100% (at Day 6) and 36% (at Day 4) in treated shrimp against viral and bacterial infection, respectively. Mortality of PG-supplemented diets in treated shrimps against WSSV infection was also found to be much lower (P < 0.05) than that of the control group.  相似文献   

18.
Development of inexpensive and simple culture media is always favorable for recombinant protein over-expression in E. coli. The effects of medium composition on the production of recombinant human granulocyte-colony stimulating factor (rh-GCSF) were investigated in batch culture of E. coli BL21 (DE3) [pET23a-hgcsf]. First, the optimum medium for production of rh-GCSF was determined; and, then it was shown that mixture of amino acid addition at induction time, which was determined on the basis of amino acids frequency in the recombinant protein, increases recombinant protein expression level significantly. Furthermore, the effect of glucose concentration on productivity of rh-GCSF was investigated; 20 g/l of glucose will result in maximum attainable biomass and rh-GCSF in this process. At optimum conditions, a cell dry weight of 10.5 g/l, an expression level of about 35% of total cellular protein, rh-GCSF concentration of 1.75 ± 0.1 g/l, and overall rh-GCSF yield of 165 ± 5 mg/g were obtained.  相似文献   

19.
A hairy root culture system of Calotropis gigantea was established and effects of mechanical wounding (MW) and elicitors [methyl jasmonate (MJ), yeast extract (YE) and chitosan (CS)] on cardenolide production were investigated. All treatments stimulated the production of cardenolide in hairy root cultures of C. gigantea. CS was the most effective elicitor, followed by MJ. YE and MW also improved cardenolide yield in individual treatments. The highest cardenolide yield (1,050 ± 55 mg/l) was obtained after adding 50 mg CS/l for 20 days, which was 2.7-fold higher than the control.  相似文献   

20.
An efficient in vitro plant regeneration protocol for Swertia chirata Buch.-Ham. ex Wall (Gentianaceae), a critically endangered Himalayan medicinal herb, was developed using shoot tip explants derived from in vitro grown seedlings. Media with 2% sucrose and various types of hormones markedly influenced in vitro propagation of S. chirata. An in vitro shootlet production system using Murashige and Skoog (MS) medium with various hormones such as BAP, KN and TDZ was established. BAP at 1.0 mg/l and KN, 0.1 mg/l induced highest number of multiple shoots (42.16 ± 1.05) per explant. Micro-proliferated shoots were transferred to elongation medium amended with GA3 (0.1 mg/l) and hormone free basal medium, after which they were transferred to rooting medium. The highest frequency of rooting (22.48 ± 1.08) was obtained in half-strength MS medium supplemented with NAA, 0.1 mg/l after testing with different auxins at various concentrations within 4 weeks of transfer to the rooting medium. Hardening was successfully attained under controlled conditions inside the plant tissue culture room. This method could effectively be applied for the conservation and clonal propagation to meet the pharmaceutical demands.  相似文献   

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