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1.
Justin van der Westhuyzen Richard C. Cantrill† F. Fernandes-Costa Jack Metz 《Journal of neurochemistry》1982,37(3):543-549
Abstract: The Egyptian fruit bat Rousettus aegyptiacus develops severe vitamin B12 deficiency when fed a diet of fresh peeled fruit and water. In a group of bats fed this diet, B12 concentrations in the serum and brain were low, and neurological impairment, evidenced by deficient or absent hindlimb groping or grasping ability and climbing difficulties, was manifest. Control bats fed the identical diet supplemented with B12 showed no such changes. Fatty acid analysis of whole brain homogenates showed a higher level of 20:4 in the deficient group. Phosphatidylcholine showed a marginally higher percentage of 18:3. The total percentage of branched chain fatty acids of phos-phatidylethanolamine was four times higher in deficient brains, comprising 2% of the total. Sphingomyelin showed a slightly higher percentage of 15:0, and a significantly lower percentage of long chain fatty acids C-24 and longer ( p < 0.01). The compositions of nonhydroxy fatty acids in cerebroside were unchanged. Examination of phospholipids showed that 8.9 ± 0.4% of total phosphorus was present as sphingomyelin in deficient bats, compared with 11.9 ± 1.2% in control animals (p < 0.05). There were no statistically significant differences in the concentrations of total brain lipid, protein, phospholipid, glycosphingolipid, cholesterol and plasmalogen between B12 -deficient and control bats. 相似文献
2.
A. Hernandez-Mendoza D. Guzman-de-Peña H.S. Garcia 《Journal of applied microbiology》2009,107(2):395-403
Aims: To assess the ability of five probiotic bacteria to bind aflatoxin B1 and to determine the key role of teichoic acids in the binding mechanism.
Methods and Results: The strains were incubated in aqueous solutions containing aflatoxin B1 (AFB1 ). The amount of free toxin was quantified by HPLC. Stability of the bacteria–aflatoxin complex was evaluated by repeated washes with buffer. In order to understand the binding process, protoplasts, spheroplasts and cell wall components of two strains were analysed to assess their capacity to bind AFB1 . Additionally, the role of teichoic acids in the AFB1 binding process was assessed. Lactobacillus reuteri strain NRRL14171 and Lactobacillus casei strain Shirota were the most efficient strains for binding AFB1 . The stability of the AFB1 –bacteria complex appears to be related to the binding ability of a particular strain; AFB1 binding was also pH-dependent. Our results suggest that teichoic acids could be responsible for this ability.
Conclusions: Our results provide information concerning AFB1 binding by previously untested strains, leading to enhanced understanding of the mechanism by which probiotic bacteria bind AFB1 .
Significance and Impact of the Study: Our results support the suggestion that some probiotic bacteria could prevent absorption of aflatoxin from the gastrointestinal tract. 相似文献
Methods and Results: The strains were incubated in aqueous solutions containing aflatoxin B
Conclusions: Our results provide information concerning AFB
Significance and Impact of the Study: Our results support the suggestion that some probiotic bacteria could prevent absorption of aflatoxin from the gastrointestinal tract. 相似文献
3.
PATRICIA F. UPHILL FREDERIKA JACOB PARVINDER LALL 《Journal of applied microbiology》1977,43(3):333-344
The vitamin B12 -producing capacity of micro-organisms isolated from baboon faeces and gastric contents was measured using Lactobacillus leichmannii . The animals were fed either a diet deficient in or supplemented with vitamin B12 (controls). Samples of gastric and small intestinal contents, obtained at laparotomy from two young vitamin B12 -deprived baboons, contained varying quantities of vitamin B12 . Many of the organisms isolated from these aspirates produced vitamin B12 in vitro . The highest levels of vitamin B12 were produced by anaerobic organisms. Gastric juice samples from vitamin B12 deprived and control baboons contained similar types of organisms with like vitamin B12 -producing capacity. The vitamin B12 content, pH and total bacterial counts of gastric juice samples aspirated after a 6 h fast from vitamin B12 deprived baboons were not significantly different from those of the control animals. The pH values of gastric juice samples aspirated 18 h after feeding, however, were significantly lower than those of 6 h fasting samples in both groups. The mean vitamin B12 levels in the total volumes of gastric juice aspirated after each fasting period were similar. The possible involvement of the gastrointestinal flora in the vitamin B12 status of the baboon is discussed. 相似文献
4.
Aims: To test the fumonisin B1 - producing ability of Fusarium proliferatum strains isolated from Welsh onion ( Allium fistulosum ) plants and seeds of commercial cultivars in Japan and to examine the applicability of PCR-based assays to discriminate between fumonisin B1 -producing and nonproducing isolates.
Methods and Results: Fumonisin B1 levels in 20 Fusarium isolates obtained from Welsh onion plants and seeds of seven commercial cultivars were determined by HPLC. Thirteen of the 20 isolates produced fumonisin B1 . PCR assay with FUM1 gene-specific primers amplified a DNA fragment (700 bp) only from fumonisin-producing isolates.
Conclusions: Fusarium proliferatum isolates that can produce fumonisin B1 were often associated with wilted Welsh onion plants and seeds of some commercial cultivars. The PCR assay with FUM1 gene-specific primers has the potential to discriminate between fumonisin B1 -producing and nonproducing isolates.
Significance and Impact of the Study: This study revealed that F. proliferatum producing fumonisin B1 is associated with Welsh onion plants and that commercial cultivar seeds may be contaminated with the fungus. PCR amplification of FUM1 gene can be a useful tool for the rapid identification of fumonisin B1 -producing F. proliferatum isolates. 相似文献
Methods and Results: Fumonisin B
Conclusions: Fusarium proliferatum isolates that can produce fumonisin B
Significance and Impact of the Study: This study revealed that F. proliferatum producing fumonisin B
5.
Abstract. 1. In insects, larval diet can have a major impact on development, survival, and reproductive success. However, resource availability at the adult phase of the life cycle is also likely to have strong effects in species where there is an extended period of sexual maturation following adult eclosion.
2. The effect of diet on the survival and reproductive success of the lekking Hawaiian fruit fly, Drosophila grimshawi , was explored. Two generations of emerging adults were exposed to one of two feeding regimes: 'constant' and 'varied' (corresponding to food 'each day' or 'every other day' respectively). The impact of resource availability on survival and reproductive success in each generation was then investigated.
3. The probability of survival to 5 weeks old was higher for individuals fed a constant diet than individuals fed a varied diet, but was comparable for males and females.
4. There was a significant maternal effect on offspring survival. Offspring whose mothers were reared on a constant feeding regime had higher survival than offspring whose mothers were reared on a varied diet.
5. There was no relationship between feeding regime and the quantity of pheromones deposited by males (a measure of male reproductive investment); however F2 sons were more likely to deposit pheromones and deposited a larger quantity of pheromone than their F1 sires. The number and sex ratio of offspring (a measure of female reproductive effort) emerging from the F1 generation was unrelated to maternal or paternal feeding regime.
6. The implications of variation in the foraging environment for mate choice in D. grimshawi are discussed. 相似文献
2. The effect of diet on the survival and reproductive success of the lekking Hawaiian fruit fly, Drosophila grimshawi , was explored. Two generations of emerging adults were exposed to one of two feeding regimes: 'constant' and 'varied' (corresponding to food 'each day' or 'every other day' respectively). The impact of resource availability on survival and reproductive success in each generation was then investigated.
3. The probability of survival to 5 weeks old was higher for individuals fed a constant diet than individuals fed a varied diet, but was comparable for males and females.
4. There was a significant maternal effect on offspring survival. Offspring whose mothers were reared on a constant feeding regime had higher survival than offspring whose mothers were reared on a varied diet.
5. There was no relationship between feeding regime and the quantity of pheromones deposited by males (a measure of male reproductive investment); however F
6. The implications of variation in the foraging environment for mate choice in D. grimshawi are discussed. 相似文献
6.
V. Niderkorn D.P. Morgavi B. Aboab M. Lemaire H. Boudra 《Journal of applied microbiology》2009,106(3):977-985
Aims: The ability of lactic acid bacteria (LAB) to bind fumonisins B1 and B2 (FB1 , FB2 ) in fermented foods and feeds and in the gastrointestinal tract could contribute to decrease their bioavailability and toxic effects on farm animals and humans. The aim of this work was to identify the bacterial cell wall component(s) and the functional group(s) of FB involved in the LAB–FB interaction.
Methods and Results: The effect of physicochemical, enzymatic and genetic treatments of bacteria and the removal/inactivation of the functional groups of FB on toxin binding were evaluated. Treatments affecting the bacterial wall polysaccharides, lipids and proteins increased binding, while those degrading peptidoglycan (PG) partially decreased it. In addition, purified PG from Gram-positive bacteria bound FB in a manner analogue to that of intact LAB. For FB, tricarballylic acid (TCA) chains play a significant role in binding as hydrolysed FB had less affinity for LAB.
Conclusions: Peptidoglycan and TCA are important components of LAB and FB, respectively, involved in the binding interaction.
Significance and Impact of the Study: Lactic acid bacteria binding efficiency seems related to the peptide moiety structure of the PG. This information can be used to select probiotics with increased FB binding efficiency. 相似文献
Methods and Results: The effect of physicochemical, enzymatic and genetic treatments of bacteria and the removal/inactivation of the functional groups of FB on toxin binding were evaluated. Treatments affecting the bacterial wall polysaccharides, lipids and proteins increased binding, while those degrading peptidoglycan (PG) partially decreased it. In addition, purified PG from Gram-positive bacteria bound FB in a manner analogue to that of intact LAB. For FB, tricarballylic acid (TCA) chains play a significant role in binding as hydrolysed FB had less affinity for LAB.
Conclusions: Peptidoglycan and TCA are important components of LAB and FB, respectively, involved in the binding interaction.
Significance and Impact of the Study: Lactic acid bacteria binding efficiency seems related to the peptide moiety structure of the PG. This information can be used to select probiotics with increased FB binding efficiency. 相似文献
7.
J. J. A. McLAUGHLIN 《The Journal of eukaryotic microbiology》1958,5(1):75-81
SYNOPSIS. The nutritional requirements of 3 isolates of Prymnesium parvum (2 Israeli, 1 Scottish) included vitamin B12 and thiamine. For comparison, 2 other brackish chrysomonads were studied: Monochrysis lutheri isolated by Droop in Scotland and Isochrysis galbana purified by McLaughlin from a culture obtained from the Plymouth laboratory.
The isolates of Prymnesium parvum and Isochrysis galbana had a molecular B12 specificity like Ochromonas malhamensis : no response to Factor B, pseudovitamin B12 , Factor A or Factor H. M. lutheri , in contrast, responded to pseudovitamin B12 , Factor H, and Factor A.
Thiamine was essential; 1.0 μg.% allowed full growth of P. parvum. The NaCl concentration for good growth was 0.3–5.0%; growth was possible from 6–12%. Dark growth was not achieved.
Ammonia, as suggested from its use in suppressing outbreaks of P. parvum , was sharply inhibitory, less so at high concentrations of NaCl or at acid pH.
Nitrate, ammonia, arginine, asparagine, methionine, histidine, alanine, glycine, serine, proline, leucine, isoleucine, tyrosine, aspartic and glutamic acids, acetylurea, and creatine served as nitrogen sources in both acid and alkaline media.
The phosphate requirement of P. parvum and M. lutheri and Isochrysis galbana was satisfied by inorganic phosphate, commercial glycerophosphate, yeast adenylic acid, cytidylic acid, monoethyl phosphate, and riboflavin monophosphate.
Laboratory cultures in defined media of the isolates of P. parvum were toxigenic to Lebistes and Gambusia. Culture fluids from alkaline media were more toxic than those from acid media, as previously noted in Israel.
Culture media suitable for production of large quantities of these organisms were developed. 相似文献
The isolates of Prymnesium parvum and Isochrysis galbana had a molecular B
Thiamine was essential; 1.0 μg.% allowed full growth of P. parvum. The NaCl concentration for good growth was 0.3–5.0%; growth was possible from 6–12%. Dark growth was not achieved.
Ammonia, as suggested from its use in suppressing outbreaks of P. parvum , was sharply inhibitory, less so at high concentrations of NaCl or at acid pH.
Nitrate, ammonia, arginine, asparagine, methionine, histidine, alanine, glycine, serine, proline, leucine, isoleucine, tyrosine, aspartic and glutamic acids, acetylurea, and creatine served as nitrogen sources in both acid and alkaline media.
The phosphate requirement of P. parvum and M. lutheri and Isochrysis galbana was satisfied by inorganic phosphate, commercial glycerophosphate, yeast adenylic acid, cytidylic acid, monoethyl phosphate, and riboflavin monophosphate.
Laboratory cultures in defined media of the isolates of P. parvum were toxigenic to Lebistes and Gambusia. Culture fluids from alkaline media were more toxic than those from acid media, as previously noted in Israel.
Culture media suitable for production of large quantities of these organisms were developed. 相似文献
8.
As a versatile cofactor for many enzymes catalyzing important biochemical reactions, vitamin B6 is required for all cellular organisms. In contrast to bacteria, fungi and plants, which have the ability to synthesize vitamin B6 de novo , animals have to take up the vitamin from their diet. Plants are the major source of vitamin B6 for animals. The recent identification of vitamin B6 biosynthetic enzymes PDX1 and PDX2 in plants makes it possible to regulate the biosynthesis of this important vitamin. In this study, we generated Arabidopsis plants overexpressing the PDX1 and/or PDX2 gene and used a liquid chromatography/mass spectrometry/mass spectrometry method to determine the levels of different forms of vitamin B6 in these transgenic plants. It was found that expression of the PDX genes under control of the CaMV 35S promoter caused only a limited increase in pyridoxine contents in dry seeds but not in shoots or roots. When using the Arabidopsis seed-specific 12S promoter to drive the expression of the PDX genes, the levels of vitamin B6 increased more than twofold in transgenic plants. Our work demonstrates that it is feasible to enhance vitamin B6 content in seeds by metabolic engineering. 相似文献
9.
Abstract: Diapause induction and photoperiodic response curves were determined for 33 strains of Tetranychus pueraricola derived from kudzu vine at three constant temperatures (15, 18 and 20°C) under a short-day condition (10 : 14 h; light : dark). Females of all but one of the strains entered diapause at all three temperatures with little variation in diapause percentages among the strains. The exception was the southernmost strain, which was found to be a non-diapause (ND) strain. The critical photoperiod gradually decreased towards the south at a rate of about 1 h for each 5 degrees of latitude. The diapause strains (D1 and D2) exhibited 100% diapause, whereas the ND strain exhibited 0% diapause. By crossing these strains, we determined that 'non-diapause' was a dominant character over 'diapause' and the character was controlled by simple Mendelian inheritance. To clarify why the female progeny from the crosses between the D1 and ND strains did not segregate into the diapause and non-diapause phenotypes in a 1:1 ratio in the B1 generation, round-robin crosses were carried out among the three strains. The results showed that the F1 generation was reproductively compatible and showed high egg hatchability with a female-biased sex ratio. In the B1 generation, the crosses between the D1 and ND strains and between the D1 and D2 strains exhibited extremely low egg hatchability and produced mostly female progeny, whereas offspring from the crosses between the D2 and ND strains showed more than 50% hatchability for B1 eggs and a female-biased sex ratio. Thus, the absence of segregation observed in the crosses between the D1 and ND strains appears to be due to the severe hybrid breakdown that occurred in the B1 generation. 相似文献
10.
V. Cusumano G.B. Costa R. Trifiletti R.A. Merendino G. Mancuso 《FEMS immunology and medical microbiology》1995,10(2):151-156
Abstract Contamination of food with mycotoxins is a major health problem. Impairment of several immune functions has been repeatedly reported in animals fed with contaminated fodder. Since the liver is a major target of toxicity by aflatoxins, the effects of aflatoxins B1, and its hepatic metabolites Q1 and M1 on Kupffer cell function was investigated in vitro. Aflatoxin B1 induced significant ( P < 0.05) inhibition of phagocytosis, intracellular killing of Candida albicans , and intrinsic anti-Herpes virus activity at concentrations as low as 0.01 pg ml−1 . Aflatoxin Q1 and M1 had similar effects on phagocytosis and microbicidal activity, but were two- to ten-fold less potent than aflatoxin B1 . 相似文献
11.
Increasing tolerance to Cry1Ac cotton from cotton bollworm, Helicoverpa armigera, was confirmed in Bt cotton farming area of China 总被引:1,自引:0,他引:1
GUO-PING LI KONG-MING WU FRED GOULD JIAN-KANG WANG JIN MIAO XI-WU GAO YU-YUAN GUO 《Ecological Entomology》2007,32(4):366-375
Abstract. 1. Changes in the frequency of Cry1Ac resistance genes and shifts in tolerance of cotton bollworm, Helicoverpa armigera , to the Cry1Ac toxin were assessed using bioassays of F1 and F2 offspring of isofemale lines from Anci County of Hebei Province (a multiple-crop system including corn, soybean, peanut, and Bt cotton) and Xiajin County of Shandong Province (an intensive Bt cotton planting area) in Northern China during 2002–2005.
2. A conservative analysis of the overall results indicated that there was a small increase in the frequency of major, non-recessive resistance genes over time.
3. The relative average development ratings [RADR – growth rate of a line on a Bt diet in proportion to the growth rate on a non-Bt (NBT) diet] of the bollworm larvae in F1 tests increased significantly from year to year, indicating a gradual trend towards higher tolerance to Cry1Ac in the field populations.
4. There were also significant positive correlations between RADR of the lines in the F1 generation and the RADR of their F2 offspring, indicating that the tolerance was genetically based.
5. Quantitative genetic simulation analysis showed that resistance of H . armigera to Bt cotton in Xiajin could evolve to a high level in 11–15 years if no effective resistance management measures are carried out. 相似文献
2. A conservative analysis of the overall results indicated that there was a small increase in the frequency of major, non-recessive resistance genes over time.
3. The relative average development ratings [RADR – growth rate of a line on a Bt diet in proportion to the growth rate on a non-Bt (NBT) diet] of the bollworm larvae in F
4. There were also significant positive correlations between RADR of the lines in the F
5. Quantitative genetic simulation analysis showed that resistance of H . armigera to Bt cotton in Xiajin could evolve to a high level in 11–15 years if no effective resistance management measures are carried out. 相似文献
12.
Abstract. 1. The population abundance and age structure of Rhopalosiphum padi , one of the most common maize aphid species, on transgenic Bt (expressing the Cry1Ab protein) and non-Bt isogenic maize was studied in commercial plots during three crop seasons.
2. A higher density of aphids, particularly alates and young nymphs, occurred in Bt plots at very young maize development stages, corresponding to the settlement period, in the 3 years studied. Possible causes are discussed. After this period, there were no differences between Bt and non-Bt maize.
3. Mortality, development, and reproduction of the offspring of alate forms of R. padi and the offspring of different generations of apterous forms fed with Bt maize were evaluated in the laboratory under controlled conditions.
4. The developmental and pre-reproductive times of the offspring of the first generation of alatae were shorter and the intrinsic rate of natural increase ( r m ) higher when aphids fed on Bt maize. The opposite occurs with the offspring of the first generation of apterous mothers, which have lower nymphal and adult mortality, shorter developmental and pre-reproductive times, a higher effective fecundity rate, and greater r m , when fed on non-Bt maize. The differences in aphid development on the two cultivars may be linked to changes in host-plant quality due to pleiotropic effects of the genetic modification.
5. No differences on aphid mortality, developmental and pre-reproductive times, fecundity, and r m were found between the offspring of apterous aphids maintained on Bt or non-Bt maize for several generations. 相似文献
2. A higher density of aphids, particularly alates and young nymphs, occurred in Bt plots at very young maize development stages, corresponding to the settlement period, in the 3 years studied. Possible causes are discussed. After this period, there were no differences between Bt and non-Bt maize.
3. Mortality, development, and reproduction of the offspring of alate forms of R. padi and the offspring of different generations of apterous forms fed with Bt maize were evaluated in the laboratory under controlled conditions.
4. The developmental and pre-reproductive times of the offspring of the first generation of alatae were shorter and the intrinsic rate of natural increase ( r
5. No differences on aphid mortality, developmental and pre-reproductive times, fecundity, and r
13.
The effect of vitamin B6 on the levels of tissue selenium (Se) and glutathione peroxidase (GSH-Px) was studied. Male Wistar 4-week-old rats were fed a vitamin B6-Se-deficient basal diet for 2 weeks, then divided into 10 groups of five or six rats and fed their respective diets for 4 weeks. The experimental design was a 2×2×2 factorial with two levels of vitamin B6, two forms of Se, and two levels of Se, plus two extra groups (vitamin B6-supplemented and deficient without Se). Vitamin B6 was 0 and 250 μg pyridoxine-HCl/100 g of diet; Se forms were Na2SeO3 and DL-selenomethionine; Se levels were 0.5 and 5.0 mg Se/kg of diet. Regardless of form or level of Se, vitamin B6-deficient rats had lower body weights and organ weights than vitamin B6-supplemented rats. At 5.0 mg Se/kg of diet, Na2SeO3 caused a further depression. Vitamin B6 deficiency resulted in a higher Se level and GSH-Px activity in plasma of rats fed selenomethionine. However, Se content an GSH-Px activity in erythrocytes were significantly elevated in vitamin B6-supplemented rats compared with vitamin B6-deficient rats. Se levels in muscle and heart were significantly lower in vitamin B6-deficient groups fed Na2SeO3 than in vitamin B6-supplemented groups. Vitamin B6-deficient rats fed selenomethionine had higher Se levels in muscle, heart, spleen, liver, and kidneys than vitamin B6-supplemented rats. Activity of GSH-Px in muscle, heart, and spleen was significantly lower in vitamin B6-deficient groups than in vitamin B6-supplemented groups, regardless of form of Se. A significant decrease of GSH-Px in liver was observed in vitamin B6-deficient rats fed selenomethionine compared with vitamin B6-supplemented rats, whereas no significant decrease was observed in those fed Na2SeO3. These results suggest that vitamin B6 is involved in the distribution and transportation of Se in body and the metabolism of selenomethionine in liver. 相似文献
14.
Abstract: Bradykinin receptors have been subdivided into at least two major pharmacological subtypes, B1 and B2 . The cDNAs encoding functional B2 receptors have recently been cloned, but no molecular information exists at present on the B1 receptor. In this article, we describe experiments examining the possible relationship between the mRNAs encoding the B1 and B2 types of receptor. We showed previously that the Human fibroblast cell line W138 expresses both B1 and B2 receptors. In this report, we describe oocyte expression experiments showing that the B1 receptor in W138 human fibroblast cells is encoded by a distinct mRNA ∼2 kb shorter than that encoding the B2 receptor. We have used an antisense approach in conjunction with the oocyte expression system to demonstrate that the two messages differ in sequence at several locations throughout the length of the B2 sequence. Taken together with the mixed pharmacology exhibited in some expression systems by the cloned mouse receptor, the data indicate that B1 -type pharmacology may arise from two independent molecular mechanisms. 相似文献
15.
Abstract. 1. Factors affecting the nutritional ecology of mixed-feeding, polyphagous herbivores are poorly understood. Mixed-feeding herbivores do better when they consume both forb and grass species although they typically feed primarily on forbs, which are of relatively higher protein content than grasses.
2. In a field experiment, we examined the effects of nitrogen and phosphorus fertilization and associated changes in host-plant C:N:P on proportional grass consumption by a mixed-feeding insect herbivore, Melanoplus bivittatus , using natural abundance stable carbon isotope (12 C/13 C) methods. We also examined a grass-feeding ( Phoetaliotes nebrascensis ) and forb-feeding ( Hesperotettix viridis ) species.
3. The C isotope signatures of M. bivittatus collected from plots fertilized with nitrogen (+N), phosphorus (+P), nitrogen and phosphorus (+N+P) and no fertilizer were compared with the C isotope signatures of plants in those plots to determine the proportion of assimilated C derived from C4 grasses and C3 forbs in each plot. We also examined the relationship between M. bivittatus diets and plant C:N:P stoichiometry.
4. The proportion of grass assimilated approximately doubled in N-fertilized treatments (39.1 ± 0.1%) compared with non-fertilized treatments (19 ± <0.1%), an increase associated with decreased C:N and increased N:P of grasses.
5. These results indicate that mixed-feeding M. bivittatus can selectively feed to balance C:N:P intake even when choosing between two structurally and chemically different groups of plants.
6. The strong relationship between diet selection and grass stoichiometry also suggests that plant nutrient composition may be more important than defensive chemistry in food choice. 相似文献
2. In a field experiment, we examined the effects of nitrogen and phosphorus fertilization and associated changes in host-plant C:N:P on proportional grass consumption by a mixed-feeding insect herbivore, Melanoplus bivittatus , using natural abundance stable carbon isotope (
3. The C isotope signatures of M. bivittatus collected from plots fertilized with nitrogen (+N), phosphorus (+P), nitrogen and phosphorus (+N+P) and no fertilizer were compared with the C isotope signatures of plants in those plots to determine the proportion of assimilated C derived from C
4. The proportion of grass assimilated approximately doubled in N-fertilized treatments (39.1 ± 0.1%) compared with non-fertilized treatments (19 ± <0.1%), an increase associated with decreased C:N and increased N:P of grasses.
5. These results indicate that mixed-feeding M. bivittatus can selectively feed to balance C:N:P intake even when choosing between two structurally and chemically different groups of plants.
6. The strong relationship between diet selection and grass stoichiometry also suggests that plant nutrient composition may be more important than defensive chemistry in food choice. 相似文献
16.
17.
Aims: To find out the cumulative effect of the nutritional parameters and to enhance the production of jasmonic acid (JA) in static fermentation by Lasiodiplodia theobromae using response surface methodology (RSM).
Method and Results: Malt extract, sucrose, NaNO3 and MgSO4 .7H2 O were analysed by a 30-trial central composite design using RSM for optimizing their concentrations in the medium and the effect of their mutual interaction on JA production. Sucrose and NaNO3 were found highly significant in influencing the JA production. Malt extract and MgSO4 .7H2 O showed an effect on the JA production in interaction with other variables. When the optimum values of the parameters obtained through RSM (19·95 g l−1 malt extract, 50 g l−1 sucrose, 7·5 g l−1 NaNO3 and 3·51 g l−1 MgSO4 .7H2 O) were applied, 32% increase in JA production (299 mg l−1 ) was observed in comparison with 225 mg l−1 of JA produced with same media components not analysed by RSM and subsequently validated the statistical model.
Conclusions: Increase in JA production was achieved by optimizing the nutritional parameters.
Significance and Impact of the Study: This is the first report of using RSM for optimizing a medium for JA production. It resulted in an increase in JA production without augmentation of costly additives. 相似文献
Method and Results: Malt extract, sucrose, NaNO
Conclusions: Increase in JA production was achieved by optimizing the nutritional parameters.
Significance and Impact of the Study: This is the first report of using RSM for optimizing a medium for JA production. It resulted in an increase in JA production without augmentation of costly additives. 相似文献
18.
Aim The distributions of Chinese spiders are used to form biotic regions and to infer biogeographical patterns.
Location China.
Methods China was initially divided into 294 quadrats of 2° latitude by 2° longitude. The distributions of 958 species of spiders were summarized for each quadrat. Subsequently, these quadrats were pooled into 28 areas based on topographical characteristics and to a lesser extent on the distributions of spiders. Parsimony analysis of endemicity (PAE) was used to classify the 28 areas based on the shared distributional patterns of spiders.
Results China was found to have seven major biogeographical regions based on the distributional patterns of spiders: Western Northern region (clade B2 : Tibetan Plateau and Inner Mongolia-Xinjiang subregions), Central Northern region (clade B3 ), Eastern Northern region (clade B4 ), Central region (clade C2 ), Eastern Southern region (clade C3 ), Western Southern region (clade C4 ), and Central Southern region (clade C5 ).
Main conclusions The distributional patterns of Chinese spiders correspond broadly to geological provinces. A comparison of the geological provinces and the distributional patterns of spiders reveals that the spiders occur south of the geological provinces. Furthermore, a general biogeographical classification with five natural areas is suggested as follows: Tibetan Plateau, Central Northern, Eastern Northern, Western Northern (excluding Tibetan Plateau), and Southern regions. 相似文献
Location China.
Methods China was initially divided into 294 quadrats of 2° latitude by 2° longitude. The distributions of 958 species of spiders were summarized for each quadrat. Subsequently, these quadrats were pooled into 28 areas based on topographical characteristics and to a lesser extent on the distributions of spiders. Parsimony analysis of endemicity (PAE) was used to classify the 28 areas based on the shared distributional patterns of spiders.
Results China was found to have seven major biogeographical regions based on the distributional patterns of spiders: Western Northern region (clade B
Main conclusions The distributional patterns of Chinese spiders correspond broadly to geological provinces. A comparison of the geological provinces and the distributional patterns of spiders reveals that the spiders occur south of the geological provinces. Furthermore, a general biogeographical classification with five natural areas is suggested as follows: Tibetan Plateau, Central Northern, Eastern Northern, Western Northern (excluding Tibetan Plateau), and Southern regions. 相似文献
19.
Control of Aspergillus section Flavi growth and aflatoxin accumulation by plant essential oils 总被引:1,自引:0,他引:1
Aims: The antifungal effect of Pimpinella anisum (anise), Pëumus boldus (boldus), Mentha piperita (peppermint), Origanum vulgare (oregano) and Minthosthachys verticillata (peperina) essential oils against Aspergillus section Flavi (two isolates of Aspergillus parasiticus and two isolates of Aspergillus flavus ) was evaluated in maize meal extract agar at 0·982 and 0·955 water activities, at 25°C.
Methods and Results: The percentage of germination, germ-tube elongation rate, growth rate and aflatoxin B1 (AFB1 ) accumulation at different essential oils concentrations were evaluated. Anise and boldus essential oils were the most inhibitory at 500 mg kg−1 to all growth parameters of the fungus. These essential oils inhibited the percentage of germination, germ-tube elongation rate and fungal growth. AFB1 accumulation was completely inhibited by anise, boldus and oregano essential oils. Peperina and peppermint essential oils inhibited AFB1 production by 85–90% in all concentrations assayed.
Conclusions: Anise and boldus essential oils could be considered as effective fungitoxicans for Aspergillus section flavi .
Significance and Impact of the Study: Our results suggest that these phytochemical compounds could be used alone or in conjunction with other substances to control the presence of aflatoxigenic fungi in stored maize. 相似文献
Methods and Results: The percentage of germination, germ-tube elongation rate, growth rate and aflatoxin B
Conclusions: Anise and boldus essential oils could be considered as effective fungitoxicans for Aspergillus section flavi .
Significance and Impact of the Study: Our results suggest that these phytochemical compounds could be used alone or in conjunction with other substances to control the presence of aflatoxigenic fungi in stored maize. 相似文献
20.
Inhibition of Helicobacter pylori Infection in Humans by Lactobacillus reuteri ATCC 55730 and Effect on Eradication Therapy: A Pilot Study 总被引:3,自引:0,他引:3
Ruggiero Francavilla Elena Lionetti Stefania Paola Castellaneta Anna Maria Magistà Giovanni Maurogiovanni Nunzia Bucci Angela De Canio Flavia Indrio Luciano Cavallo Enzo Ierardi Vito Leonardo Miniello 《Helicobacter》2008,13(2):127-134
Background: Several studies report an inhibitory effect of probiotics on Helicobacter pylori .
Aim: To test whether Lactobacillus reuteri ATCC 55730 reduces H. pylori intragastric load in vivo, decreases dyspeptic symptoms, and affects eradication rates after conventional treatment.
Materials and Methods: In a double-blind placebo-controlled study, 40 H. pylori -positive subjects were given L. reuteri once a day for 4 weeks or placebo. All underwent upper endoscopy,13 C-urea breath test, and H. pylori stool antigen determination at entry and 13 C-urea breath test and H. pylori stool antigen (used as both qualitative and semiquantitative markers) after 4 weeks of treatment. Sequential treatment was administered subsequently to all.
Results: In vivo, L. reuteri reduces H. pylori load as semiquantitatively assessed by both13 C-urea breath test δ -value and H. pylori stool antigen quantification after 4 weeks of treatment ( p < .05). No change was shown in patients receiving placebo. L. reuteri administration was followed by a significant decrease in the Gastrointestinal Symptom Rating Scale as compared to pretreatment value ( p < .05) that was not present in those receiving placebo ( p = not significant). No difference in eradication rates was observed.
Conclusions: L. reuteri effectively suppresses H. pylori infection in humans and decreases the occurrence of dyspeptic symptoms. Nevertheless, it does not seem to affect antibiotic therapy outcome. 相似文献
Aim: To test whether Lactobacillus reuteri ATCC 55730 reduces H. pylori intragastric load in vivo, decreases dyspeptic symptoms, and affects eradication rates after conventional treatment.
Materials and Methods: In a double-blind placebo-controlled study, 40 H. pylori -positive subjects were given L. reuteri once a day for 4 weeks or placebo. All underwent upper endoscopy,
Results: In vivo, L. reuteri reduces H. pylori load as semiquantitatively assessed by both
Conclusions: L. reuteri effectively suppresses H. pylori infection in humans and decreases the occurrence of dyspeptic symptoms. Nevertheless, it does not seem to affect antibiotic therapy outcome. 相似文献