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Many felids are threatened by loss of habitat, lack of genetic diversity, and over-exploitation. The reintroduction of bobcats (Felis rufus) to Cumberland Island, Georgia provided an opportunity to reintroduce a mid-sized felid without the concern for species survival that is paramount with endangered species. We captured bobcats from the coastal plain region of Georgia, briefly held them in captivity, and released them on Cumberland Island. We describe and evaluate the protocols and techniques used to accomplish the reintroduction. Future reintroductions of felids should consider the problem of post-release dispersal, although our island was relatively isolated and inhibited dispersal. Also, any reintroduction effort should invest effort and resources into post-release monitoring of the population. Empirical knowledge about the effects of spatial distribution, genetics, population dynamics, especially mechanisms of population regulation, behavior, and environmental conditions on the viability of populations is critical to the conservation of endangered species. Future research of the bobcats on Cumberland Island will be able to address aspects of the population and genetic dynamics of a small, insular felid population.  相似文献   

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Intensive fish breeding in artificial freshwater reservoirs and ponds is often accompanied by epidemics of invasive parasitic diseases. In the USSR, much attention is given to the study of fish parasites and diseases, revealing a range of protozoan and helminth parasites that can cause significant economic losses to the fish industry (Table I ; Refs 1-5).  相似文献   

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Non-B DNA conformations, mutagenesis and disease   总被引:10,自引:0,他引:10  
Recent discoveries have revealed that simple repeating DNA sequences, which are known to adopt non-B DNA conformations (such as triplexes, cruciforms, slipped structures, left-handed Z-DNA and tetraplexes), are mutagenic. The mutagenesis is due to the non-B DNA conformation rather than to the DNA sequence per se in the orthodox right-handed Watson-Crick B-form. The human genetic consequences of these non-B structures are approximately 20 neurological diseases, approximately 50 genomic disorders (caused by gross deletions, inversions, duplications and translocations), and several psychiatric diseases involving polymorphisms in simple repeating sequences. Thus, the convergence of biochemical, genetic and genomic studies has demonstrated a new paradigm implicating the non-B DNA conformations as the mutagenesis specificity determinants, not the sequences as such.  相似文献   

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Georgia is situated in the Caucasus region where Eastern Europe and Western Asia meet. The country covers a territory of 69,700 km² and its population is 4.385 million people. Formerly a part of the Soviet Union, Georgia restored its independence in 1991. Since then the country has struggled to renovate its economical and political structure, while saving the best from the past and exploring new opportunities. Bioscience is an essential part of this process. We have interviewed several leading Georgian scientists and asked them to describe the problems and accomplishments in their areas of bioscience.  相似文献   

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Perkinsus marinus in coastal Georgia, USA, following a prolonged drought   总被引:1,自引:0,他引:1  
Oysters Crassostrea virginica are 'keystone' estuarine species in the southeastern USA, providing essential fish habitat, food for human consumption, filtration of water bodies, and protection against shoreline erosion. Relatively few oyster pathology studies have been conducted in Georgia. The parasitic protozoan Perkinsus marinus was first observed here in the 1960s, but has not been investigated since the late 1990s, when increasing oyster infection levels were apparent. In the late 1990s and early 2000s, the region suffered a prolonged drought, resulting in elevated salinities and the proliferation of various diseases in the marine environment. By 2003, salinities had returned to normal levels, but the effect of the drought on oysters was unknown. In June 2003, oyster reefs throughout Chatham County were sampled to evaluate the prevalence and intensity of P. marinus. The disease appears to have remained prevalent in the coastal waters of Georgia (100% prevalence at some sites), but the intensity was low, ranging from 0 to 1.83 on a scale where heavy infections rated a score of 5. While the disease did not occur at levels high enough to cause oyster mortalities, further monitoring, particularly on a temporal scale, is warranted.  相似文献   

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Two new desmoscolecid species are described: Desmoscolex koloensis sp. nov. and D. parakoloensis sp. nov. Additional information is given on Desmoscolex (Desmolorenzenia) montana, D. sieverti and D. fennicus. The genus Desmolorenzenia is considered a subgenus of Desmoscolex. Pareudesmoscolex lacustris represents a juvenile state of Desmocolex dussarti. Some reflections are made on terrestrial and freshwater desmoscolecids.  相似文献   

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The information about cetacean occurrence around the Island of South Georgia is scarce. With the main goal of gathering information on a feeding ground of humpback whales (Megaptera novaeangliae) that winter in Brazilian waters, we conducted an expedition to South Georgia. We present here the information regarding cetacean sightings during the expedition. From 28 January to 2 March, 2006 we carried out 13 research cruises, covering 700 nautical miles and 110 h of observation. We registered 10 sightings, in 7 h of ad libitum observations, of the following species: Megaptera novaeangliae, Eubalaena australis, Balaenoptera physalus, Mesoplodon layardii, Orcinus orca and Lagenorhynchus cruciger. We present data on location, depth, group size, structure, and behavior for this geographical area of essential importance for cetacean conservation.  相似文献   

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Molecular Genetics and Genomics - Spores have been preferred for mutagenic treatment of Physcomitrella patens. Many mutant strains are, however, sexually sterile and so do not produce spores. We...  相似文献   

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