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1.
Microbiological synthesis of higher alcohols (1-butanol, isobutanol, 2-methyl-1-butanol, etc.) from plant biomass is critically important due to their advantages over ethanol as a motor fuel. In recent years, the use of branched-chain amino acid (BCAA) biosynthesis pathways together with heterologous Ehrlich pathway enzyme system (Hazelwood et al. in Appl Environ Microbiol 74:2259–2266, 2008) has been proposed by the Liao group as an alternative approach to aerobic production of higher alcohols as new-generation biofuels (Atsumi et al. in Nature 451:86–90, 2008; Atsumi et al. in Appl Microbiol Biotechnol 85:651–657, 2010; Cann and Liao in Appl Microbiol Biotechnol 81:89–98, 2008; Connor and Liao in Appl Environ Microbiol 74:5769–5775, 2008; Shen and Liao in Metab Eng 10:312–320, 2008; Yan and Liao in J Ind Microbiol Biotechnol 36:471–479, 2009). On the basis of these remarkable investigations, we re-engineered Escherichia coli valine-producing strain H-81, which possess overexpressed ilvGMED operon, for the aerobic conversion of sugar into isobutanol. To redirect valine biosynthesis to the production of alcohol, we also—as has been demonstrated previously (Atsumi et al. in Nature 451:86–90, 2008; Atsumi et al. in Appl Microbiol Biotechnol 85:651–657, 2010; Cann and Liao in Appl Microbiol Biotechnol 81:89–98, 2008; Connor and Liao in Appl Environ Microbiol 74:5769–5775, 2008; Shen and Liao in Metab Eng 10:312–320, 2008; Yan and Liao in J Ind Microbiol Biotechnol 36:471–479, 2009)—used enzymes of Ehrlich pathway. In particular, in our study, the following heterologous proteins were exploited: branched-chain 2-keto acid decarboxylase (BCKAD) encoded by the kdcA gene from Lactococcus lactis with rare codons substituted, and alcohol dehydrogenase (ADH) encoded by the ADH2 gene from Saccharomyces cerevisiae. We show that expression of both of these genes in the valine-producing strain H-81 results in accumulation of isobutanol instead of valine. Expression of BCKAD alone also resulted in isobutanol accumulation in the culture broth, supporting earlier obtained data (Atsumi et al. in Appl Microbiol Biotechnol 85:651–657, 2010) that native ADHs of E. coli are also capable of isobutanol production. Thus, in this work, isobutanol synthesis by E. coli was achieved using enzymes similar to but somewhat different from those previously used.  相似文献   

2.
A chemically defined diet is a powerful tool for the study of nutritional physiology. We have developed a simple, standardized diet for Rhytidoponera ants to facilitate experiments on nutrititional regulation and nutrient balancing in these ants. Colonies of Rhytidoponera metallica were fed with a standardized diet, containing a 1:2 ratio of total proteins to digestible carbohydrates. After 8 weeks, colony performance (number of brood raised, the mass of pupae, and the mortality of workers) was superior to that of colonies fed with Bhatkar-Whitcomb diet and similar to colonies fed with Drosophila and honey-water. Received 10 March 2008; revised 1 May 2008; accepted 6 May 2008.  相似文献   

3.
We studied the effect of great-horned owl (Bubo virginianus) removal on piping plover (Charadrius melodus) hatchling survival on Missouri River sandbars (2008–2009). Owl removal increased daily survival of piping plover chicks in 2008 (β = 2.03, 95% CI: 0.04–4.02), but this effect decreased with increasing age of the chick (β = −0.42, 95% CI: −0.81 to −0.03). Results for 2009 were similar in direction but not significant. Survival was higher in 2008 than in 2009, regardless of owl capture, indicating that even if owl capture consistently were effective at increasing survival, overall survival resulting from trapping may vary annually. Owl trapping was a successful means to raise chick survival on the Missouri River in ≥1 year and could be used at other sites experiencing depressed chick survival due to avian predators. © 2011 The Wildlife Society.  相似文献   

4.
Two yellow fever outbreaks (YFOs) ocurred in northeastern Argentina between November 2007 and October 2008, seriously affecting populations of two howler monkey species: the brown howler Alouatta guariba clamitans and the black howler Alouatta caraya. Both howlers live syntopically in El Piñalito Provincial Park, Misiones, where four groups (36 individuals) were studied since January 2005. The first dead howlers were found on January 20, 2008, in El Piñalito. Systematic searches found 14 dead howlers within the area (12 from the study groups and two from neighboring groups), with only two young seen on January 25, 2008, and none found since up to December 2008. In October 2008, another YFO hit howler monkey populations from El Soberbio, Misiones. Overall, 59 howlers were found dead in Misiones from November 2007 to December 2008. Thanks to the alert of the howler's death in El Piñalito, a prompt human vaccination campaign started in the area. Wild howler monkey populations from both species are in a delicate situation in Misiones, especially the brown howler, an already endangered species in Argentina and endemic to the Atlantic Forest. If we add the recurrence of YFOs to the reduction of suitable habitat to small fragments, it could be only a matter of time until howler populations disappear from the Upper Paraná Atlantic Forest in Misiones. Am. J. Primatol. 72:475–480, 2010. © 2010 Wiley‐Liss, Inc.  相似文献   

5.
BACKGROUND: In utero exposure to carbimazole for maternal hyperthyroidism has been reported to cause choanal atresia. There are case reports of patent vitello‐intestinal duct and Meckel's diverticulum in similar association. CASE: We report another such instance of an infant who was exposed to carbimazole in utero, presenting with bilateral choanal atresia and patent vitello‐intestinal duct. CONCLUSIONS: As there seems to be no reports of a possible association between propylthiouracil and congenital malformations, it may be safer to use propylthiouracil instead of carbimazole. Birth Defects Research (Part A), 2008. © 2008 Wiley‐Liss, Inc.  相似文献   

6.
The Fennoscandian arctic fox (Vulpes lagopus) population is endangered due to overharvest and competition with the larger red fox (Vulpes vulpes). In this study, we have screened the population in Sweden for endoparasites by analysis of non-invasively faecal samples collected at reproductive dens during two summers, one with low food abundance (2008) and the other with high food abundance (2010). Eggs, larvae and oocysts of a total of 14 different endoparasites were identified with a species richness per inhabited den of 3.2 (CI95% ± 0.48) in 2008 and 2.7 (CI95% ± 0.72) in 2010. Capillariidae-like eggs was identified at 59% of the dens in 2008 and 57% in 2010 and Toxocara canis with 7% (2008) and 30% (2010); Toxascaris leonina with 93% (2008) and 65% (2010); Uncinaria stenocephala 65% (2008) and 39% (2010); Crenosoma vulpis 3% (2008) and 4% (2010); Trichuris sp. 7% (2008) and 4% (2010); Cystoisospora canis-like oocysts 28% (2008) and 26% (2010); Cystoisospora ohiensis-like oocysts 38% (2008) and 4% (2010); Eimeria sp. 7% (2008) and 9% (2010); Sarcocystis sp. 3% (2008) and 9% (2010); Taenia sp. 10% (2008) and 4% (2010); Mesocestoides sp. 3% (2008) and 0% (2010); Balantidium sp. 0% (2008) and 9% (2010) and Spiruroidea-like eggs 0% (2008) and 4% (2010). To our knowledge, Balantidium sp., Sarcocystis sp. and Trichuris sp. has never been described before in wild arctic foxes.  相似文献   

7.
Recent phylogenetic studies indicating that termites are eusocial cockroaches closely related to the genus Cryptocercus have generated fresh interest in wood-feeding Blattaria. Here we summarize the social biology of the wood-feeding genus Salganea (Blaberidae: Panesthiinae). As in Cryptocercus, Salganea exhibits long term, biparental care that includes the defense and feeding of young nymphs. Unlike Cryptocercus, however, Salganea is iteroparous: most studied species reproduce periodically over their lifetime. These divergent reproductive strategies are likely related to parental costs associated with their differing reproductive modes: Cryptocercus is oviparous, while Salganea is ovoviviparous. The pattern of parental investment associated with ovoviviparous reproduction may be one reason why Salganea and other ovoviviparous wood-feeding cockroach lineages did not evolve eusociality. Received 21 August 2007; revised 25 January 2008; accepted 22 Feburary 2008.  相似文献   

8.
Aims: To monitor variations in the bacterial community and fermentation products of maize silage within and between bunker silos. Methods and Results: Silage samples were collected in 2008 and 2009 from three dairy farms, wherein the farmers arranged for a contractor to produce maize silage using bunker silos. Silage was prepared using a lactic acid bacteria (LAB) inoculant consisting of Enterococcus faecium, Lactobacillus plantarum and Lactobacillus buchneri. Eight samples were collected from each bunker silo; 4 ‘outer’ and 4 ‘inner’ samples were collected from near the top and the bottom of the silo. The dry matter, lactic acid, acetic acid, ethanol, 1‐propanol and 1,2‐propanediol contents differed between bunker silos in both sampling years. Higher acetic acid, 1‐propanol and 1,2‐propanediol contents were found in the bottom than the top layers in the 2008 samples, and higher lactic acid content was found in the top than the bottom layers in the 2009 samples. The bacterial community varied more between bunker silos than within a bunker silo in the 2008 samples, whereas differences between the top and the bottom layers were seen across bunker silos in the 2009 samples. The inoculated LAB were uniformly distributed, while several nonconventional silage bacteria were also detected. Lactobacillus acetotolerans, Lactobacillus panis and Acetobacter pasteurianus were detected in both years. Stenotrophomonas maltophilia was detected in the 2008 samples, and Lactobacillus reuteri, Acinetobacter sp. and Rahnella sp. were detected in the 2009 samples. Conclusions: Although differences were seen within and between bunker silos, the bacterial community may indicate a different relationship between bunker silos and sampling locations within a bunker silo from that indicated by the fermentation products. Significance and Impact of the Study: Analysis of bacterial community can help understand how diverse non‐LAB and LAB species are involved in the ensiling process of bunker‐made maize silage.  相似文献   

9.
A block synthetic approach is presented for the synthesis of the pentasaccharide repeating unit of the O-antigen of E. coli O83:K24:H31 strain, present in the “Colifant” vaccine. The target pentasaccharide has been synthesized by coupling a disaccharide with a trisaccharide in excellent yield. Yields are quite satisfactory in all intermediate steps. A concise synthesis of the pentasaccharide repeating unit of the O-antigen of E. coli O83:K24:H31 strain, present in the COLINFANT vaccine is presented. The target pentasaccharide has been synthesized following a block synthetic strategy by coupling a disaccharide with a trisaccharide in excellent yield.  相似文献   

10.
Both monogyne and polygyne colonies of Solenopsis invicta now occupy Taiwan. Although venom alkaloids of these ants have been described and synthesized, we here report on a quantitative analysis of the two social forms for the first time. The alkaloids were studied by gas chromatography coupled to mass spectrometry (GC-MS), and six major venom alkaloids were detectable in both types of workers. Both C13:C13:1 and C15:C15:1 ratios in alkaloid venom of monogyne workers were statistically higher than that of polygyne workers, but the sum of proportions of unsaturated alkaloids of polygyne workers was significantly higher than that of monogyne workers, regardless of growth temperature, sampling seasons or geographic location. Results of this study demonstrate that the difference in the proportions of unsaturated alkaloids and the ratios of C13:C13:1 and C15:C15:1 alkaloids might be a good indicator for differentiating monogyne and polygyne forms of S. invicta. Received 20 February 2008; revised 4 July 2008; accepted 5 August 2008.  相似文献   

11.
Correction to Shavit Grievink L, Penny D, Hendy MD, Holland BR: LineageSpecificSeqgen: generating sequence data with lineage-specific variation in the proportion of variable sites. BMC Evol Biol 2008, 8 (1):317.  相似文献   

12.
Seed predation is an important ecological and evolutionary force that directly affects the distribution of plant species. Copaifera langsdorffii is a tropical tree species with supra‐annual fruiting, which has its seeds predated by a specialist endogenous insect (Rynochenus brevicollis: Curculionidae) in the Brazilian savanna. Three hypotheses were addressed: (i) the predator satiation hypothesis, (ii) the resource concentration hypothesis and (iii) the larger seed predation hypothesis. A total of 112 individual C. langsdorffii were monitored monthly from January to August during four consecutive years (from 2008 to 2011) to determine the presence of fruits on each plant. All trees produced fruits in the year 2008, whereas none of them produced flowers or fruits in 2009 or 2010. Moreover, only 65 individuals (58%) marked in 2008 produced fruits in 2011. The number of fruits per plant was approximately 21% greater in 2008 than in 2011, while the percentage of seed predation was 76% greater in 2011, thereby supporting the predator satiation hypothesis. The percentage of seeds predated was not affected by the number of fruits per plant. Therefore, our data did not support the resource concentration hypothesis. Plants producing large seeds experienced more seed predation by R. brevicollis, supporting the larger seed predation hypothesis. In addition, we also observed a positive relationship between seed volume and adult R. brevicollis weight. This study demonstrates the importance of supra‐annual fruiting for increasing survivorship of C. langsdorffii seeds both at the individual and the population level, and suggests that seed predators select plants producing large seeds as a way of increasing the number of offspring.  相似文献   

13.
Correction to Wu DD, Irwin DM, Zhang YP: Molecular evolution of the keratin associated protein gene family in mammals, role in the evolution of mammalian hair. BMC Evol Biol 2008, 8:241.  相似文献   

14.
A response to Ziegler A, Faber C, Mueller S, Bartolomaeus T: Systematic comparison and reconstruction of sea urchin (Echinoidea) internal anatomy: a novel approach using magnetic resonance imaging.BMC Biol 2008, 6: 33.  相似文献   

15.
Eustenogaster nigra in the northern part of Vietnam has a synchronized, bivoltine colony cycle with winter dormancy. The males go through the winter dormancy in an envelope nest together with virgin females, and mating takes place after they emerge from the winter dormancy. The individuals overwintering in a given nest are often non-sibs. Females, including those emerging from the winter dormancy, start their colony singly. These suggest that winter nests function simply as hibernacula. The solitary life in E. nigra in northern Vietnam is discussed in comparison with that of E. scitula in central Vietnam where the mating usually takes place before entering the winter dormancy and only females overwinter. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Received 8 June 2008; revised 18 September 2008; accepted 23 September 2008.  相似文献   

16.
Chronic bacterial prostatitis (CBP) is, usually, caused by uropathogens, especially gram-negative bacilli, although infection is sometimes due to Gram-positive and atypical microorganisms. A recent increasing in prevalence of Gram-positive strains has been reported. The aim of this study was to explore the epidemiological features and resistance rates in uropathogens isolated from CBP outpatients in last 10 years. All consecutive outpatients with demonstrated CBP attending a single Sexually Transmitted Disease centre from January 1997 and December 2008, were enrolled and underwent microbiological cultures in first void early morning urine, midstream urine, expressed prostatic secretion, and post prostate massage urine. Prevalence of different bacterial strains was stratified in four different periods: 1997–1999, 2000–2002, 2003–2005, 2006–2008. Any changes observed in epidemiological features and resistance rates in uropathogens over the whole study period have been analyzed. The present study has been planned, thus, as in vitro study. From 6,221 patients, 4,601 Gram-positive and 1,620 Gram-negative bacterial strains have been isolated. Enterococcus faecalis and Escherichia coli strains are the first and second frequent pathogens found, respectively. Significant differences between E. faecalis prevalence in the 1997–1999 and 2006–2008 periods were found. E. coli showed a significant difference between prevalence in 1997–1999 and 2006–2008 periods. Gram-positive organisms showed a decreasing of susceptibility to ciprofloxacin as well as Gram-negative strains, while a good susceptibility to the levofloxacin was evidenced. E. faecalis prevalence seemed to be raised in 2006–2008 periods. Moreover, a decreasing of activity of ciprofloxacin and a good activity profile of levofloxacin have been reported.  相似文献   

17.
Aragán C. F. and Escudero A. 2008. Mating system of Helianthemum squamatum (Cistaceae), a gypsophile specialist of semi-arid Mediterranean environments. Bot. Helv. 118: 129–137 Plants living on gypsum have received remarkably little study, despite being one of the most important groups of endemic and rare plants in arid and semi-arid regions. This work is among the first to study the mating system of a gypsophyte, Helianthemum squamatum (Cistaceae), which is a short-lived perennial endemic to gypsum habitats of the Iberian Peninsula. We carried out a hand-pollination experiment, considering the following pollination treatments: autogamy, geitonogamy, xenogamy and control (open-pollination). Generalized linear mixed models were fitted to evaluate the effect of the treatment on the fruit set and the number of viable seeds yielded per fruit. Both response variables were significantly higher in the xenogamy treatment than in the autogamy and geitonogamy treatments. No significant differences were detected between the xenogamy treatment and the control group, indicating that H. squamatum is mainly an outcrosser although partially self-compatible. Our results also suggest that pollen limitation may only slightly affect the reproductive success of H. squamatum. In contrast with the general tendency towards self-compatibility previously described in short-lived species of the Cistaceae, this outcrossing mating system resembles the one of long-lived perennials Submitted 10 April 2008; Accepted 25 August 2008 Subject editor: Christian Parisod  相似文献   

18.
Semen collection and preservation is the first step toward the development of an artificial insemination program in endangered Pteropus spp. Semen was collected by manual stimulation from a single “human‐habituated” P. alecto. Manual stimulation resulted in the successful collection of motile spermatozoa on 17 of 34 attempts. The semen had a pH of 8.2 (n=2). With the exception of volume, seminal characteristics (concentration, motility, acrosome and plasma membrane status) were similar to those collected previously by electro‐ejaculation. Zoo Biol 27:159–164, 2008. © 2008 Wiley‐Liss, Inc.  相似文献   

19.
Reviews are provided for four books relevant to the studies on the biodiversity conservation of insects: Insect diversity conservation (Samways 2005), Insect conservation biology (Stewart et al. 2007), Ecology of insects: concepts and applications (Speight et al. 2008, 2nd edn), and Insect conservation: a handbook of approaches and methods (Samways et al. 2009).  相似文献   

20.
The primitively social bumblebee Bombus terrestris is an ecological model species as well as an important agricultural pollinator. As part of the ongoing development of genomic resources for this model organism, we have constructed a publicly available bacterial artificial chromosome (BAC) library from males of a field-derived colony. We have shown that this library has a high coverage, which allows any particular sequence to be retrieved from at least one clone with a probability of 99.7%. We have further demonstrated the library’s usefulness by successfully screening it with probes derived both from previously described B. terrestris genes and candidate genes from another bumblebee species and the honeybee. This library will facilitate genomic studies in B. terrestris and will allow for novel comparative studies in the social Hymenoptera. Received 12 March 2008; revised 13 September 2008; accepted 17 September 2008. R. Schmid-Hempel: contact for data repository of this BAC library  相似文献   

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