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991.
Costas Grivas Stavros M. Xirouchakis Costas Christodoulou Beatriz Carcamo-Aboitiz Panagiotis Georgiakakis Michalis Probonas 《Journal of Ethology》2009,27(1):105-116
We describe here an automated surveillance system that was installed in a bearded vulture (Gypaetus barbatus) nest in Crete during 2003–2006 with the aim of studying siblicide in this species. The system caused only minimal levels
of disturbance to the birds and was capable of operating autonomously for more than 1 week. It comprised (1) a nest monitoring
subsystem (camera, microphone, battery with a charge controller and a transmitter together with an antenna), which was supported
by a solar panel, and (2) a recording subsystem (antenna receiver, video signal controller and a remote controlled PC through
a GSM modem) that compressed the audio–video signal and provided real time monitoring. Two-egg clutches with a 7-day laying
and hatching interval were recorded while hatching asynchrony was also determined through an analysis of the bioacoustic data.
Food delivery rate and number of feeds to the first chick increased after the hatching of its sibling although not significantly
so. Of the aggressive interactions recorded, 98% were initiated by the dominant chick and resulted in an average of 246 ± 157
peckings per day. Supplementary feeding did not produce any significant correlation between feeding rate and sibling aggression.
The second chick survived 5 days and died as a result of starvation accelerated by sibling aggression. Intervention measures
aimed at increasing the survival chance of the second chick should be undertaken when the latter is 1–2 days old. 相似文献
992.
Stomach content data from 798 Pacific walruses ( Odobenus rosmarus divergens ) collected during 1952–1991 were analyzed using a method that evaluates the stage of digestion of prey remains. Non-molluscan prey taxa were not well represented in previous interpretations of walrus diet due to digestion biases. Stomach contents least affected by digestion (fresh stomachs) contained more prey taxa than stomachs of an unknown or more digested state. Bivalves, gastropods, and polychaete worms were the most frequent prey items in both the Bering and Chukchi seas, although bivalves occurred more frequently in stomachs from the Bering Sea and gastropods occurred more frequently in stomachs from the Chukchi Sea. Male and female walruses consumed essentially the same prey when in the same location. Using only fresh stomachs collected between 1975 and 1985, there was no significant difference between the proportion that contained mostly bivalves and the proportion that contained non-bivalve prey items. Earlier interpretations of a change in walrus diet in this period compared to the prior two decades may have been due to digestion as well as sampling biases. Current climatic changes may affect walrus's access to diverse, productive shallow water feeding areas. 相似文献
993.
Xingjiang Li Zhi Zheng Zhaojun Wei Shaotong Jiang Lijun Pan Shibing Weng 《World journal of microbiology & biotechnology》2009,25(4):667-677
Purpose In this paper, the high yield mutant strain was expected to be obtained for the industrial bioconversion of corn straw hydrolyte
to succinic acid. Methods API biochemical reactions and 16S r RNA sequence analysis were carried out for identification, and then the strain’s metabolic
pathway and its relevant enzymes were discussed for the metabolic flux analysis (MFA). The X-ray of synchronous radiation
and site-directed mutagenesis were imported for decreasing those byproducts, and the metabolic technics was also modulated.
Results Identification showed that the succinic-acid-producing strain S.JST belonged to Actinobacillus succinogenes species. Metabolic pathway analysis indicated that this strain had the character of utilizing glucose and xylose simultaneously,
which was a great advantage considering the fact that most crop straw hydrolyte included glucose and xylose. Metabolic flux
analysis showed that acetic acid and alcohol competed with the flux of succinic acid, and the analysis of [H] reducing power
balance investigated that the [H] electronic donor produced in the cell was not enough for the metabolism of succinic acid.
Then X-ray mutagenesis showed that the flux of byproduct acetic acid was decreased to 0.666 from 1.233 mmol/g DW h and that
two mutated sites were found in pta (gene of phosphotransacetylase) from mutant strain M.JSTP, but less succinic acid was produced due to the worse lacking in
the supply of [H] reducing power. The site-directed mutagenesis showed that the flux of byproduct alcohol was successfully
decreased to 0.029 from 1.303 mmol/g DW h. Then, surrounding the flux ratio of HMP to EMP, the metabolic technics was modulated
with the addition of citrate in order to improve the balance of [H] reducing power, thus the succinic acid flux of the mutant
M.JSTA was increased to 3.163 from 2.480 mmol/g DW h comparing with the parent strain S.JST. Conclusions The mutant strain obtained in this paper deserves to be scaled-up. 相似文献
994.
Feral cats have been directly responsible for the extinction of numerous species on islands worldwide, including endemic species
of mammals, birds and reptiles. The diet of feral cats in the main habitats of the Canary Islands, as generally occurred on
oceanic islands, is mainly composed of introduced mammals, and native species of birds, reptiles and insects. The impact of
feral cat upon the endangered species was assessed by evaluating their relative abundance in the cats’ diet and by considering
their current conservation status. A total of 68 different preys were identified at species level in all studies carried out
in the Canary Islands (5 mammals, 16 birds, 15 reptiles and 32 invertebrates). From all the species preyed by feral cats in
the Canary Islands, only four of them are considered threatened by the IUCN Red List of Threatened Species: one endemic bird
Saxicola dacotiae and three endemic giant lizards, Gallotia simonyi, Gallotia intermedia, and Gallotia gomerana. Although some efforts on management control have been carried out, it is necessary to enforce these conservation activities
on those areas of Tenerife, La Gomera and El Hierro where giant lizards are still present. Furthermore some local areas where
endangered bird species are highly predated should be protected. Nevertheless, it is important to take into account the presence
of other introduced species such as rats, mice or rabbits in order to avoid problems derived from the hyperpredation process
and mesopredator release effect. 相似文献
995.
The extent to which black‐backed jackals (Canis mesomelas) selectively consume domestic sheep (Ovis aries) compared to wild prey is unknown. Using faecal analysis and prey surveys, we determined the seasonal diet and prey selection of jackals on a small‐livestock farm in South Africa. Sheep comprised 25–48% of the biomass consumed by jackals across seasons, and consumption peaked during the lambing seasons, indicating sheep often were the main food resource for jackals. Another main food resource was wild ungulates <50 kg, primarily springbok (Antidorcas marsupialis) and steenbok (Raphicerus campestris), which comprised 8–47% of the biomass consumed. Other important food items were mammals 1–3 kg (4–16%), which included hares (Lepus spp.) and springhares (Pedetes capensis), and small rodents (10–14%). Compared to the biomass available, jackals selectively consumed mammals 1–3 kg over sheep across all seasons, whereas wild ungulates <50 kg were selectively consumed over sheep in most seasons. Our results showed that jackals selectively consumed different food items throughout the year and that wild prey were consistently selected over sheep. 相似文献
996.
Ranunculus weyleri is a species endemic to Mallorca Island (western Mediterranean basin) that is currently threatened due to its reduced geographical distribution and disjunct, isolated populations. It is a small, perennial herb that inhabits rocky environments, together with other endemic plants with creeping life-forms. In the present study, for the first time the reproductive biology of the species was investigated in terms of its floral phenology (floral stages and times of formation), pollen/ovule (P/O) ratios, and fruit and seed setting under natural and pollen manipulation experiments, assessing the breeding system, pollination vectors and pollen limitations. Cross-pollinations among populations were performed to evaluate the levels of compatibility between populations. In addition, the floral displays and the reproductive outputs of four wild populations were determined. The observed high P/O ratios, results of the hand-pollination experiments, and flower traits indicate that this species is predominantly allogamous. Combinations of both insects (belonging to Coleoptera, Diptera, Lepidoptera and Hymenoptera) and wind (ambophily) constitute the main pollination vectors, and pollen limitation was observed. Interpopulation crossing was effective, and exogamic depression was not present, as evidenced by the fecundity levels. The predation of the floral stems by herbivores (mainly goats) severely limits the reproductive success of this endemic species in wild populations. Finally, several ways of action are proposed for R. weyleri conservation. 相似文献
997.
CONTEXT:
Tumor protein 53 (tp53) is one of the candidate gene proposed for neural tube defects, which affects central nervous system during early embryonic development, on the basis of mouse models.AIMS:
The present study is an attempt to unfold the possible role of tp53 G412C polymorphism in the incidence of neural tube defect (NTDs) in humans.SETTINGS AND DESIGN:
Case-control study was carried out in government hospitals of Delhi, India.MATERIALS AND METHODS:
Subjects comprised of 100 mothers of NTD children and 100 matched control mothers. Information on some environmental exposures was collected along with blood samples. After DNA extraction, the genotyping of tp53 G412C polymorphism was carried out by PCR-RFLP method.Statistical Analysys:
Fisher Exact or Chi square test, binary logistic model, and odds ratio (95% confidence interval) calculations were used to evaluate effect of risk factors on NTDs using SPSS v17.0.RESULTS:
The ‘CC’ genotype of tp53 G412C showed protective effect towards the development of anencephaly and/or encephalocele (OR: 0.44; 95% CI: 0.19-1.00); however, no significant difference among overall NTD cases and controls was observed (P>0.05). Further segregation of all subjects based on 2 different communities, Hindus and Muslims, the association of ‘CC’ genotype of the polymorphism with reduced NTD risk was observed among Hindu community (OR: 0.33; 95% CI: 0.13-0.79).CONCLUSION:
The study highlights the selective advantage provided by maternal ‘CC’ genotype, thereby reducing risk of cephalic NTDs, probably due to the lower apoptotic activity of the protein, however, more specifically in the presence of community-specific microenvironment. 相似文献998.
长江口中国花鲈食性分析 总被引:4,自引:0,他引:4
中国花鲈(Lateolabrax maculatus)是长江口重要的经济鱼类之一。根据2010年7月至10月在长江口崇明东滩团结沙和东旺沙水域采集到的胃含物样品,对中国花鲈的摄食习性进行了研究。结果表明,从中国花鲈胃含物中共鉴定出6类27种饵料生物,其多样性指数H’值为2.484,均匀度指数J’为0.7535,优势指数D为0.1262。采用百分比相对重要性指数(IRI%)和综合指标优势指数(Ip)分析的结果较一致,鱼类是长江口中国花鲈夏季主要食物,其百分比相对重要性指数(IRI%)和综合指标优势指数(Ip)分别为82.63%和94.48,鮻(Liza haematocheila)为优势饵料生物(IRI%=41.89,Ip=53.20)。团结沙和东旺沙中国花鲈食性差异较大,主成分分析(PCA)表明鲚属(Coilia spp.)、舌虾虎鱼(Glossogobius giuris)、脊尾白虾(Exopalaemoncarinicauda)和雷伊著名团水虱(Gnorimosphaeroma rayi)是造成这种差异的主要饵料生物种类。 相似文献
999.
Manuel Jesús Lpez‐Rodríguez Jos Manuel Tierno de Figueroa Tiziano Bo Alessandro Mogni Stefano Fenoglio 《International Review of Hydrobiology》2012,97(2):117-123
Leuctridae is the richest stonefly family on the European continent, with many species of Leuctra often coexisting in sympatry in the same lotic environment. In this work we studied the life cycle and feeding habits of two species, Leuctra fusca and L. hippopus, coexisting in a small Italian Apennine stream. The life cycles of the two species are non‐overlapping, i.e., periods of nymphal growth and adult emergence are separated. Nymphs of both species feed mainly on detritus, but quantities of coarse particulate organic matter (CPOM) and diatoms are also ingested. Larger nymphs of both species ingest more CPOM and fewer diatoms. This suggests a similar trophic behaviour through their development. For example, they act as collector‐gatherers in their earlier instars and as collector‐gatherers or as shredders in their later instars (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
1000.
染色体片段导入系在作物遗传育种研究中的应用 总被引:5,自引:0,他引:5
染色体片段导入系是在轮回亲本的遗传背景上只含有一个或少量供体染色体片段的家系,可作为QTL分析的重要材料。在QTL检测时,染色体片段导入系的遗传背景清楚,可有效检测微效基因及隐蔽基因,准确地评价供体染色体片段的遗传效应,打破优良基因与不良基因的连锁,提高QTL检测的效率和准确性。另外,染色体片段导入系不仅可用于QTL精细定位和基因克隆、QTL间互作、QTL与环境互作以及杂种优势的研究,同时还可用于作物聚合育种和分子设计育种。本文对染色体片段导入系的构建及其在作物遗传育种中的应用进展进行了综述。 相似文献