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1.
Beijerinckia indica subsp. indica is an aerobic, acidophilic, exopolysaccharide-producing, N2-fixing soil bacterium. It is a generalist chemoorganotroph that is phylogenetically closely related to facultative and obligate methanotrophs of the genera Methylocella and Methylocapsa. Here we report the full genome sequence of this bacterium.Beijerinckia indica subsp. indica ATCC 9039 is the type strain of the genus Beijerinckia (6), a member of the Rhizobiales order of the Alphaproteobacteria. Beijerinckia spp. are commonly found as free-living bacteria in acidic soils and also in plant rhizosphere and phyllosphere environments (4). Research on Beijerinckia has suffered from chronic taxonomic confusion, with some strains of Sphingomonas and Azotobacter being misidentified in the literature: e.g., a “Beijerinckia” reported to degrade PAH has been reclassified (3). However, some Beijerinckia spp. have received research attention due to their plant growth-promoting properties (7) and for their abundant production of exoheteropolysaccharide with potential biotechnological uses (5).Genomic DNA from Beijerinckia indica subsp. indica was used to create 3-kb, 8-kb, and 40-kb DNA libraries. Sequencing, assembly, and automated annotation were performed at the Joint Genome Institute using standard procedures (U.S. Department of Energy; http://www.jgi.doe.gov/sequencing/strategy.html). The total number of paired-end shotgun Sanger reads in the assembly was 33,870. In addition, Roche 454 sequence data were included into the final assembly. Large Newbler contigs of 454 reads were chopped into 4,975 overlapping fragments of 1,000 bp and entered into the assembly as pseudoreads.The genome of B. indica subsp. indica was 4,170,153 bp. In addition, two plasmids of 181,736 and 66,727 bp were present. There are a total of 3,982 open reading frames (ORFs) predicted using Glimmer, of which 3,784 are predicted protein-coding genes and 2,695 (70%) have been assigned a predicted function. There are 134 pseudogenes, 52 tRNA genes, and three operons each containing 16S, 23S, and 5S rRNA genes. The G+C content is 57.0% (56% and 54% in the plasmids).The bacterium lacks phosphofructokinase, the key enzyme of the Embden-Meyerhof pathway. Instead, it uses the Entner-Doudoroff or pentose phosphate pathway to catabolize sugars, which is typical of free-living Rhizobiales. The majority of the genes involved in N2 fixation are clustered in two genomic islands (10 kb and 51 kb), with the notable exception of the nifS gene encoding cysteine desulfurase.Beijerinckia indica is a metabolically versatile bacterium capable of growth on a variety of organic acids, sugars, and alcohols (4). In contrast, its close phylogenetic cousins Methylocella and Methylocapsa are highly specialized methanotrophs capable of growth on very few substrates (2). However, the genome size of Beijerinckia indica compared to that of Methylocella silvestris (4.17 versus 4.30 Mbp) and the numbers of predicted protein-encoding genes (3,788 versus 3,917) are remarkably similar. A BLAST analysis indicated that the 57% of the genes in the genome of B. indica have homologues in M. silvestris (stringency threshold expectation value [E] of 1e−50). Some key pathways of one-carbon metabolism (such as the tetrahydromethanopterin and serine pathways of formaldehyde metabolism) that are present in M. silvestris appear to be absent or incomplete in B. indica, which confirms previous experiments showing that the organism is incapable of methylotrophic growth (1). However, an operon encoding a putative propane monooxygenase homologous to soluble propane/methane monooxygenases of Methylocella silvestris BL2 was identified. More in-depth comparison of these genomes will help elucidate what defines their distinct lifestyles.  相似文献   

2.
Two flavonoids, (2S)-5,7,3',4'-tetramethoxyflavanone (1) and 5,7,2',5'-tetramethoxyflavone (2) together with three known flavonoids, 7-O-methylwogonin (3), skullcapflavone I (4) and 5-hydroxy-7,2'-dimethoxyflavone (5) were isolated from the whole plant of Limnophila indica. The structures of compounds 1-5 were elucidated on the basis of spectral and chemical studies.  相似文献   

3.
In a culture of Alocasia indica (2n=28), one plant was found to be desynaptic. At pachytene, pairing apparently was complete, but at diakinesis and metaphase I on the average only 2.36 and 1.53 bivalents respectively were found. Desynapsis is of the medium-strong type according to Prakken. Later meiotic stages were irregular and pollen sterility was 95%. The origin must have been spontaneous mutation.  相似文献   

4.
Adult nymphalid butterflies possess sensilla trichodea (ST) that perceive taste in their walking legs. We examined whether the gustatory responses to mid-leg tarsal stimulation were different between Vanessa indica (rotting-food feeder) and Argyreus hyperbius (flower-nectar feeder). Sucrose, fructose, and glucose elicited behavioral responses (proboscis extension reflex: PER) and electrophysiological responses (spikes) from ST. Sugar responsiveness was similar in both species, where sucrose was the most stimulatory. Two fermentation products, ethanol and acetic acid, never induced PERs but elicited large-amplitude spikes at a concentration of >1% (w/v). The two species significantly differed in responsiveness to the binary mixtures of sucrose and the fermentation products. Ethanol enhanced the sugar responses of V. indica but slightly inhibited those of A. hyperbius. Although acetic acid suppressed the sugar responses of both species, V. indica was less susceptible than A. hyperbius. When concentration of the fermentation products increased, binary mixtures evoked large spikes together with small ones regarded as the sucrose responses. Unlike the proboscal sensilla in our previous study, the tarsal ST of both species unambiguously responded to fermentation products. These results demonstrate that the tarsal gustatory sense of V. indica is adaptive to the use of rotting foods.  相似文献   

5.
Nodal explants of rice cultivar Pathumthani 1 (PT1; short-day photoperiod insensitive) were collected, surface-disinfected, and cultured on modified MS medium under in vitro conditions for 90 d. A total of 60% nodal explants generated flowering plantlets (with one inflorescence per cluster). The net photosynthetic rate was greater, and soluble sugars (including glucose, fructose, and sucrose) accumulated to higher levels in the leaves of flowering as compared to non-flowering plants. In contrast, chlorophyll a, chlorophyll b, total chlorophyll, and total carotenoid content were enriched to a greater degree in the leaves of non-flowering as compared to flowering plants. Also, growth performance parameters, including plant height, number of leaves per plant, leaf area, fresh weight, and dry weight of plantlets derived from seedlings were superior to those of plantlets derived from nodal explants. In addition, the protocol proved to successfully induce flowering in KDML 105, a short-day photoperiod-sensitive rice cultivar.  相似文献   

6.
美人蕉核型研究   总被引:1,自引:0,他引:1  
对美人蕉体细胞染色体计数,并对其核型进行分析。结果表明,美人蕉的染色体数目为2n=18,核型公式为2n=2x=18m,属于"1A"型。  相似文献   

7.
Abstract. To investigate the ability of insects to discriminate between nutritionally balanced and unbalanced foods, fifth-instar nymphs of Locusta migratoria L. (Orthoptera: Acrididae) were given one of thirteen pairings of artificial foods differing only in their concentration of protein and carbohydrate. One food, containing a previously estimated optimum balance of these nutrients, was common to each pairing. The relative intake of this 'target' food increased on the more extreme pairings, i.e. the insects demonstrated increasingly strong preference for the balanced food when it was paired with unbalanced alternative foods. When distinctive non-nutritional flavours (tannic acid and amygdalin) were added to one or both of the foods, the insects' intake of the unbalanced foods increased, particularly on high-protein foods. It is suggested that learned associations were not involved in the observed patterns of selection and that the added flavours disrupted the chemosensory responses to nutrients used by the insects to differentiate foods in this context.  相似文献   

8.
Objectives : Despite the increasing availability of low‐ and reduced‐fat foods, Americans continue to consume more fat than recommended, which may be a contributing factor to the obesity epidemic. This investigation examined relationships between liking and household availability of high‐ and low‐fat foods and their association with dietary fat intake. Research Methods and Procedures : A food frequency questionnaire assessed percent calories from fat consumed over the past year in 85 men and 80 women. Participants reported their degree of liking 22 “high‐fat foods” (>45% calories from fat) and 22 “low‐fat foods” (<18% calories from fat), and the number and percentage (number of high‐ or low‐fat foods/total number of foods × 100) of these high‐ and low‐fat foods in their homes. Results : Hierarchical regression analyses examined the ability of liking and household availability of low‐ and high‐fat foods to predict percent dietary fat intake. After controlling for age, sex, and BMI, liking ratings for high‐ and low‐fat foods and the interaction of liking for low‐fat foods by the percentage of low‐fat foods in the household were significant predictors of percent dietary fat consumed. Greater liking of high‐fat foods and lower liking of low‐fat foods, both alone and combined with a lower percentage of low‐fat foods in the home, were predictive of higher dietary fat intake. Discussion : Interventions designed to reduce dietary fat intake should target both decreasing liking for high‐fat foods and increasing liking for low‐fat foods, along with increasing the proportion of low‐fat foods in the household.  相似文献   

9.
Flavonoids (1-4), together with ten known compounds (5-14) were isolated from the stems and roots of the mangrove plant Derris indica. Their chemical structures were elucidated by analysis of their spectroscopic data. All compounds except compounds 2 and 6 exhibited antimycobacterial activity with minimum inhibitory concentrations (MIC) between 6.25 and 200 microg/mL.  相似文献   

10.
The commercially available dog food samples (29 dry foods and 11 wet foods) were analysed for deoxynivalenol (DON) and ochratoxin A (OTA) using ELISA. All (100%) dry foods were contaminated with DON with various amount of the toxin (22-1837 μg/kg). In wet food 3 samples were found to be positive for DON in the range of 95-170 μg/kg. There were a few samples contaminated with OTA: 3 samples in dry foods (7-40 μg/kg) and 2 samples in wet foods (45 and 115 μg/kg).  相似文献   

11.
食品中重金属的存在形态及其与毒性的关系   总被引:15,自引:6,他引:15  
简要介绍了近年来有关食品中重金属形态及其毒性关系的研究进展,归纳了食品中重金属的化学形态特征、不同类型食品中重金属的存在形态、食品中重金属形态与生物有效性和毒性的关系,以及该领域中急需研究解决的问题.  相似文献   

12.
We investigated responses toward novel foods and novel objects by wild capuchins that routinely exploit visitors' foods in Brasília National Park. Given the capuchins' daily exposure to human foods and objects, we expected them to be more explorative toward novel foods and objects compared to capuchins that are not habituated to visitors. However, since the safety and palatability of potential foods have to be learned, we also expected the capuchins to be cautious about eating novel foods, as has been reported for wild and captive capuchins. Stimuli were presented on a platform in four experimental conditions: familiar food (FF), novel food (NF), familiar food plus novel object (FF+O), and novel food plus novel object (NF+O). Latencies to approach and contact the platform, and to approach and to ingest food did not differ across conditions. Nevertheless, the capuchins were significantly more responsive (measured in terms of interest, manipulation, etc.) toward familiar foods than novel foods, and ate significantly more of the former. In other words, their explorative response toward novel foods led to little consumption. Our results do not support the "readiness to eat" hypothesis, according to which a lower readiness to eat and food neophobia are the consequences of the presence of a distracting novel object. The finding that capuchins explore novel stimuli but remain cautious about eating novel foods supports the view that neophilia and neophobia are motivationally independent responses.  相似文献   

13.
Hesitancy to eat novel foods hampers the immediate enlargement of the diet but serves to limit the risk of ingesting toxic foods. Neophobia has been systematically investigated in only a few primate species, in which it appears to be affected by social influences. Surprisingly, little is known about neophobia in chimpanzees. We studied the response of eight adult captive chimpanzees to 16 foods (foods commonly eaten by humans and never tasted before by chimpanzees). Each novel food was presented twice to the chimpanzee by a familiar or an unfamiliar human. Between the two trials the human ate the food face to face with the chimpanzee (demonstration). Results showed that some foods were almost unanimously accepted, whereas others were not. Moreover, there were marked interindividual differences in food acceptance and consumption; chimpanzees ranged from being almost completely neophobic to accepting almost all foods. Familiarity with the human and the human's demonstration did not affect responses to the foods. The humans' predictions concerning the chimpanzees' acceptance of the different foods were rather good; furthermore, in seven cases out of eight the humans' preferences did not correlate with their predictions on the chimpanzees' preferences. The finding that most captive chimpanzees are initially cautious toward novel foods supports the little information there is regarding this subject in wild chimpanzees. However, the lack of influence of the humans' familiarity and demonstration on the response to food by the chimpanzees calls for more naturalistic studies, in which social influences are provided by group members. Since novel stimuli provide sensory stimulation and elicit exploration and social interest, occasional presentation of novel foods could be a promising and cheap device for feeding enrichment. Zoo Biol 21:539–548, 2002. © 2002 Wiley‐Liss, Inc.  相似文献   

14.
We review 69 studies of the diet of Badgers Meles meles L. in the former Soviet Union, using information from 58 Russian-language papers. Animal foods occurred more frequently in the diet than vegetal foods and constituted, on average, 62% of all intake by volume. The most important individual food categories were insects (30% by volume) and small mammals (20% by volume), which appear to be staple foods of Badgers over virtually the whole of the former Soviet Union. Earthworms were mentioned in only a few reports and never exceeded 5% of the diet by volume. Other animal foods included birds, reptiles, amphibians, fish, molluscs and carrion. Fruits were seasonally important in some areas while roots, tubers, bulbs, cereals and nuts were also eaten; but in general, the Soviet literature lacks detailed information about vegetal foods. Many authors comment on seasonal variation in the diet and there was statistically significant seasonal variation in the frequency with which small mammals, reptiles, insects and vegetal foods were eaten. No largescale geographical trends were apparent in the composition of the diet, but foods which were of minor importance overall, such as reptiles, amphibians and molluscs, were sometimes eaten with high frequency in particular localities. The results support the view that Badgers are opportunistic, generalist foragers, with a preference for animal foods when these are available.  相似文献   

15.
The main aim of this study was to verify if the response to novel foods in common marmoset (Callithrix jacchus) is influenced by different social settings. This question was tested in three tests involving four social groups. The data regarding the response to novel foods were collected from a total of eight food-naive young. In particular, we explored if direct contacts between food-naive and experienced individuals would have a different effect on the response to novel food by the first, in comparison with a situation in which only visual contacts were allowed. These two different social settings were then compared to a situation in which the response to novel food was not mediated by the experience of group-mates. The results showed a significantly higher number of intervals in which naive young, in social settings, were observed feeding compared with a control test. However, this result was confirmed only in the case of novel foods, not in the case of familiar foods. Furthermore, in the tests in which direct social contacts were allowed, naive young obtained food from group-mates significantly more often in the case of novel than familiar foods. This study suggests that although naive young, when left in pairs, responded quickly to novel foods without the need to observe or interact with experienced group-mates, a process of social facilitation was evident. Such a process was not observed in the case of familiar foods, confirming the hypothesis that social facilitation operates in order to acquire novel foods in the diet of the group in the long term.  相似文献   

16.
Stable carbon isotope analyses have shown that South African australopiths did not have exclusively frugivorous diets, but also consumed significant quantities of C4 foods such as grasses, sedges, or animals that ate these foods. Yet, these studies have had significant limitations. For example, hominin sample sizes were relatively small, leading some to question the veracity of the claim for australopith C4 consumption. In addition, it has been difficult to determine which C4 resources were actually utilized, which is at least partially due to a lack of stable isotope data on some purported australopith foods. Here we begin to address these lacunae by presenting carbon isotope data for 14 new hominin specimens, as well as for two potential C4 foods (termites and sedges). The new data confirm that non-C3 foods were heavily utilized by australopiths, making up about 40% and 35% of Australopithecus and Paranthropus diets respectively. Most termites in the savanna-woodland biome of the Kruger National Park, South Africa, have intermediate carbon isotope compositions indicating mixed C3/C4 diets. Only 28% of the sedges in Kruger were C4, and few if any had well-developed rhizomes and tubers that make some sedges attractive foods. We conclude that although termites and sedges might have contributed to the C4 signal in South African australopiths, other C4 foods were also important. Lastly, we suggest that the consumption of C4 foods is a fundamental hominin trait that, along with bipedalism, allowed australopiths to pioneer increasingly open and seasonal environments.  相似文献   

17.
A survey was conducted to compare the total viable fungal content and the number of different mold species encountered in 10 types of health foods labeled organically grown and in the same foods without such a label. The foods were wheat flour, corn meal, brown rice, figs, split peas, pinto beans, soybeans, walnuts, pecans, and peanuts. Results showed no consistent difference in either the total viable fungal content or the number of different mold species encountered between the labeled and unlabeled foods. Two genera of yeasts (Rhodotorula and Saccharomyces) and 22 gener of molds, including more than 65 species, were encountered. The mold flora was dominated by Aspergillus glaucus, Aspergillus niger, Aspergillus flavus, Aspergillus candidus, Penicillium cyclopium, and Penicillium viridicatum. Isolates of the genera Alternaria, Cladosporium, Fusarium, and Helminthosporium also occurred in certain foods. At least 10 toxicogenic species of Aspergillus and Penicillium were encountered. A total of 87 cultures of these species, all isolated from health foods, were screened for laboratory production of their respective toxins. Toxin production potential of these 87 cultures did not differ from that of cultures of the same species isolated from conventional foods.  相似文献   

18.
A survey was conducted to compare the total viable fungal content and the number of different mold species encountered in 10 types of health foods labeled organically grown and in the same foods without such a label. The foods were wheat flour, corn meal, brown rice, figs, split peas, pinto beans, soybeans, walnuts, pecans, and peanuts. Results showed no consistent difference in either the total viable fungal content or the number of different mold species encountered between the labeled and unlabeled foods. Two genera of yeasts (Rhodotorula and Saccharomyces) and 22 gener of molds, including more than 65 species, were encountered. The mold flora was dominated by Aspergillus glaucus, Aspergillus niger, Aspergillus flavus, Aspergillus candidus, Penicillium cyclopium, and Penicillium viridicatum. Isolates of the genera Alternaria, Cladosporium, Fusarium, and Helminthosporium also occurred in certain foods. At least 10 toxicogenic species of Aspergillus and Penicillium were encountered. A total of 87 cultures of these species, all isolated from health foods, were screened for laboratory production of their respective toxins. Toxin production potential of these 87 cultures did not differ from that of cultures of the same species isolated from conventional foods.  相似文献   

19.
20.
Ohne Zusammenfassung  相似文献   

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