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1.
Molecular genetic analysis was performed using random amplified polymorphic DNA (RAPD) on three commonly used laboratory bred rodent genera viz. mouse (Mus musculus), rat (Rattus norvegicus) and guinea pig (Cavia porcellus) as sampled from the breeding colony maintained at the Animal Facility, CSIR-Indian Institute of Toxicology Research, Lucknow. In this study, 60 samples, 20 from each genus, were analyzed for evaluation of genetic structure of rodent stocks based on polymorphic bands using RAPD markers. Thirty five random primers were assessed for RAPD analysis. Out of 35, only 20 primers generated a total of 56.88 % polymorphic bands among mice, rats and guinea pigs. The results revealed significantly variant and distinct fingerprint patterns specific to each of the genus. Within-genera analysis, the highest (89.0 %) amount of genetic homogeneity was observed in mice samples and the least (79.3 %) were observed in guinea pig samples. The amount of genetic homogeneity was observed very high within all genera. The average genetic diversity index observed was low (0.045) for mice and high (0.094) for guinea pigs. The inter-generic distances were maximum (0.8775) between mice and guinea pigs; and the minimum (0.5143) between rats and mice. The study proved that the RAPD markers are useful as genetic markers for assessment of genetic structure as well as inter-generic variability assessments.  相似文献   

2.
The diversity and properties of actinobacteria, predominant residents in coral holobionts, have been rarely documented. In this study, we aimed to explore the species diversity, antimicrobial activities and biosynthetic potential of culturable actinomycetes within the tissues of the scleractinian corals Porites lutea, Galaxea fascicularis and Acropora millepora from the South China Sea. A total of 70 strains representing 13 families and 15 genera of actinobacteria were isolated. The antimicrobial activity and biosynthetic potential of fifteen representative filamentous actinomycetes were estimated. Crude fermentation extracts of 6 strains exhibited comparable or greater activities against Vibrio alginolyticus than ciprofloxacin. Seven of the 15 actinomycetes strains possess type I polyketide synthases (PKS-I) and/or nonribosomal peptide synthetases (NRPS) genes. Nine tested strains possess type II polyketide synthases (PKS-II). Phylogenetic analysis based on 16S rRNA gene sequences indicated that these PKS and NRPS gene screening positive strains belong to genera Nocardiopsis, Pseudonocardia, Streptomyces, Micromonospora, Amycolatopsis and Prauserella. One PKS-I and four NRPS fragments showed <70 % similarity to their closest relatives, which suggested the novelty of these genes. This study helps uncover the genetic capacity of stony coral-associated actinomycetes to produce bioactive molecules.  相似文献   

3.
Microbial diversity and biogeochemical processes of the Gangxi bed with low-mineral water and a temperature gradient from 35 to 54°C were studied. The 16S rRNA gene clone libraries (over 800 clones) were obtained from microbial DNA isolated from formation water and from the primary enrichment cultures for fermenting, sulfate-reducing, methanogenic, and aerobic organotrophic prokaryotes. While both sulfate reduction and methanogenesis were registered in formation water by radioisotope techniques, the genes of sulfate-reducing prokaryotes were not revealed in the 16S rRNA gene clone library from formation water. The 16S rRNA genes of Methanobacterium congolense and Methanococcus vannielii predominated among archaeal sequences retrieved from formation water, while the genes of Methanothermobacter thermoautotrophicus, Methanomethylovorans thermophila, and Methanoculleus sp. predominated in the combined library from enrichment cultures. In the library of Bacteria 16S rRNA genes from formation water, the genes of thermophilic fermentative bacteria of the family Thermoanaerobacteriaceae predominated; the remaining sequences belonged to mesophiles (genera Brevundimonas, Sphingomonas, Oxalicibacterium, and Stenotrophomonas), the phylum Chloroflexi, and unidentified bacteria. The combined library from enrichment cultures, contained, apart from the sequences of the family Thermoanaerobacteriaceae, the genes of fermentative bacteria (genera Anaerobaculum, Coprothermobacter, Thermanaerovibrio, Soehngenia, Bacteroides, and Aminobacterium and the order Thermotogales), of aerobic hydrocarbon-oxidizing bacteria (genera Pannonibacter and Pseudomonas), and of sulfate reducers (genera Desulfomicrobium, Thermodesulfovibrio, and Desulfotomaculum). High coverage was shown for bacterial (97.6%) and archaeal (100%) clone libraries, indicating that a significant portion of the microbial diversity in the studied communities was revealed.  相似文献   

4.
5.
Saffron (Crocus sativus L), an autumn-flowering perennial sterile plant, reproduces vegetatively by underground corms. Saffron has biannual corm–root cycle that makes it an interesting candidate to study microbial dynamics in its rhizosphere and cormosphere (area under influence of corm). Culture independent 16S rRNA gene metagenomic study of rhizosphere and cormosphere of Saffron during flowering stage revealed presence of 22 genera but none of the genus was common in all the three samples. Bulk soil bacterial community was represented by 13 genera with Acidobacteria being dominant. In rhizosphere, out of eight different genera identified, Pseudomonas was the most dominant genus. Cormosphere bacteria comprised of six different genera, dominated by the genus Pantoea. This study revealed that the bacterial composition of all the three samples is significantly different (P < 0.05) from each other. This is the first report on the identification of bacteria associated with rhizosphere, cormosphere and bulk soil of Saffron, using cultivation independent 16S rRNA gene targeted metagenomic approach.  相似文献   

6.
Several groups of Archaea, all Euryarchaeota, develop in hypersaline environments (from >10 % salt up to saturation). The cultured diversity of halophilic Archaea includes the family Halobacteriaceae of aerobic or facultative anaerobic, generally red-pigmented species (47 genera and 165 species as of February 2014) and seven representatives of four genera of methanogens, most of which obtain energy from methylated amines under anaerobic conditions. Metagenomic studies have identified an additional deep lineage of Archaea in salt lakes and ponds with brines approaching NaCl saturation. Genomic information is now available for representatives of these ‘Nanohaloarchaea’, but no members of this lineage have yet been cultured. Multilocus sequence analysis is becoming increasingly popular in taxonomic studies of the Halobacteriaceae, and such studies have demonstrated that recombination of genetic traits occurs at an extremely high frequency at least in some genera. Metagenomic studies in an Antarctic lake showed that large identical regions of up to 35 kb in length can be shared by members of different genera living together in the same environment. Such observations have important implications not only for the taxonomy of the Halobacteriaceae, but also for species concepts and questions on taxonomy and classification for prokaryotic microorganisms in general.  相似文献   

7.
Two new genera of Chrysobalanaceae are described.Hunga distributed in New Caledonia, the Loyalty Islands and Papua and New Guinea, contains eight species, three new, and five formerly placed in the generaAngelesia, Licania andParinari.Kostermanthus is described to accommodate two species with united filaments formerly placed inParinari andAcioa. Both new genera are quite as distinct as others of the family and have been overlooked by undue emphasis placed on the single character of a bilocular ovary.Licania palawanensis Prance is also described; it is the second species of its genus from Malesia.  相似文献   

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9.
The diversity of coral associated fungi is not enough understood, especially for scleractinian corals. Members of Porites are common and dominant species of scleractinian corals. To date, the fungal communities associated with coral Porites pukoensis have been not reported. In this paper, the diversity and activity of coral associated fungi in P. pukoensis were explored, 23 fungal strains were isolated, belonging to 10 genera and Aspergillus sp. (30.4 %) was predominant fungal genera. The sequence of isolate C1-23 in GenBank was only 90 % similarity to the most closely related sequences. It is concluded that rich fungal symbionts are attached to P. pukoensis, the rate of isolates with antibacterial activity was up to 30 %, particularly some isolates showed stronger bioactivities to gram-negative bacteria. It is included that the diversity of coral associated fungi in P. pukoensis is abundant and its activity is obviously. So the activities of fungi in P. pukoensis were deserved for further study.  相似文献   

10.
The species composition of centric diatoms from Lake Frolikha (Transbaikal area) has been studied. The lake is located on the eastern shore of Lake Baikal and connected with it by a river. Twenty-three species of Centrophyceae from 7 genera (Aulacoseira, Cyclostephanos, Cyclotella, Discostella, Handmania, Pliocaenicus, and Stephanodiscus) have been found. The most represented genus is Aulacoseira (11 species). Fifteen species and 4 genera are new for the lake record. All revealed species are known in other lakes of the Baikal region; however Baikal endemics are absent in Lake Frolikha. The flora of centric diatoms in Lake Frolikha can be divided into two groups. The first group includes taxa common in Lake Baikal, and the second group includes taxa not typical for Lake Baikal. The level of differences between flora in Lake Baikal and Lake Frolikha is high (43%) despite the close location and connection to the river. An analysis of distribution of interesting species in Asia is presented.  相似文献   

11.
Of the many types of freshwater bodies across Iceland (e.g., lakes, springs, rivers, and ponds), greater effort has been invested in researching the freshwater Crustacea (Cladocera, Copepoda) of more permanent, larger, and deeper water bodies than on smaller or more ephemeral sites. To address this, we described the fauna of 12 shallow freshwater bodies distributed from the coast to the central highlands of Iceland. We identified 16 species in 11 genera belonging to six families of Cladocera, and 12 species in eight genera belonging to four families of Copepoda. Five of the species we identified (Alona werestschagini, Cyclops vicinus, Daphnia cristata, Diacyclops abyssicola, and Heterocope borealis) represent new distribution records for Iceland, increasing the number of species now known from this region to 34 Cladocera and 38 Copepoda taxa. Additionally, we discuss the taxonomy of some species with doubtful taxonomical status. Six crustacean taxocenes are described, each characterized by the dominance of different taxa, with bottom sediment characteristics best explaining species assemblage structure. We evaluated the relationships between Icelandic Cladocera and Copepoda faunas and those of the adjacent Svalbard, Faroe, and Shetland Islands, Greenland, and the mainland Norway. The taxonomic composition of the Icelandic fauna is dominated by widely distributed Holarctic, and secondarily Palaearctic and Nearctic species, and is more similar to the faunas of the major North Atlantic islands (64.2–71.8 % similarity) than it is to that of continental Norway.  相似文献   

12.
Anatomical study of the genusDendroseris (Compositae: Cichorieae), endemic to the Juan Fernandez Islands, was undertaken to determine if segregate genera were valid. Other questions include the significance of pith bundles and of receptacular bristles, and whether the ancestors of these peculiar rosette trees and shrubs were woody or herbaceous. Anatomical evidence, when added to that from gross morphology, suggests that the segregation as distinct genera ofRea, Phoenicoseris, andHesperoseris is probably not justified, and that they are better treated as subgenera ofDendroseris. Differences in pollen morphology, floral trichomes, achene and leaf anatomy provide good species characteristics. These all appear, respectively, as variations on a basic plan, andDendroseris can be envisaged as derived from a common stock in the Juan Fernandez Islands. The genus is not particularly primitive within the family or tribe. The presence of additional bundles in the flowers ofD. litoralis may be interpreted as related to gigantism. The separate corolla lobes inD. gigantea probably do not represent a vestige of an actinomorphic condition. Pith bundles inDendroseris may have been present in ancestors; in any case, they seem likely to have increased in prominence with increase in stem diameter. Available evidence seems to favor the interpretation of growth forms inDendroseris as derived from an herbaceous ancestry.  相似文献   

13.
Geothermal springs in Algeria have been known since the Roman Empire. They mainly locate in Eastern Algeria and are inhabited by thermophilic organisms, which include cyanobacteria forming mats and concretions. In this work, we have investigated the cyanobacterial diversity of these springs. Cyanobacteria were collected from water, concretions and mats in nine hot springs with water temperatures ranging from 39 to 93 °C. Samples were collected for isolation in culture, microscopic morphological examination, and molecular diversity analysis based on 16S rRNA gene sequences. Nineteen different cyanobacterial morphotypes were identified, the most abundant of which were three species of Leptolyngbya, accompanied by members of the genera Gloeocapsa, Gloeocapsopsis, Stigonema, Fischerella, Synechocystis, Microcoleus, Cyanobacterium, Chroococcus and Geitlerinema. Molecular diversity analyses were in good general agreement with classical identification and allowed the detection of additional species in three springs with temperatures higher than 50 °C. They corresponded to a Synechococcus clade and to relatives of the intracellularly calcifying Candidatus Gloeomargarita lithophora. The hottest springs were dominated by members of Leptolyngbya, Synechococcus-like cyanobacteria and Gloeomargarita, whereas Oscillatoriales other than Leptolyngbya, Chroococcales and Stigonematales dominated lower temperature springs. The isolation of some of these strains sets the ground for future studies on the biology of thermophilic cyanobacteria.  相似文献   

14.
InCallithrix, Saguinus, Aotus, andCallicebus other group members than the mother participate in infant care. Differences among these species are obvious in respect to the time of being off any caregiver, and in respect to the carrying position (Aotus andCallicebus). Alloparental care, a basic behaviour pattern in these species, has evolved from the parking behaviour of the prosimians. The infants are «parked» at other group members.  相似文献   

15.
Scanning electron microscopy was used to examine foliar surface features such as cuticular patterns, epicuticular wax, and trichome types in species ofAlnus, Betula, Carpinus, Corylus, andOstrya. Six trichome types are recognized in this survey, four non-glandular (acicular, filiform, aduncate, subulate) and two glandular (stipitate gland and peltate scale). The distribution of these trichomes among the genera supports the recognition of two tribes, Betuleae (Alnus andBetula) and Coryleae (Carpinus, Corylus, andOstrya). Trichome morphology can be an important supportive taxonomic character in determining evolutionary relationships.  相似文献   

16.
During helminthological examinations of teleost fishes of Ningaloo Reef, Western Australia, a new species of the enigmatic genus Plectognathotrema Layman, 1930 was discovered infecting the pot-bellied leatherjacket Pseudomonacanthus peroni (Hollard). The new species, Plectognathotrema kamegaii n. sp., is formally described, and the status of its four congeners is reviewed. Plectognathotrema hydrolagi Olson, Hanson & Pratt, 1970 is not recognised within the genus, as it differs greatly from its congeners in the form and arrangement of the vitellarium, testes and uterus, and in that it was described from a holocephalan. Plectognathotrema cephalopore Layman, 1930 and P. tsushimaense Kamegai, 1970 are morphologically similar, were described from the same host species and from close geographical localities and are considered synonymous. The new taxon is most similar to P. cephalopore, but differs from it in being much smaller and possessing a distinctly larger oral sucker relative to its body size. The generation of novel partial 28S ribosomal DNA sequences allowed a phylogenetic assessment of the genus and demonstrated that Plectognathotrema clearly belongs in the Zoogonidae Odhner, 1902, rather than in the Fellodistomidae Nicoll, 1909, where it is currently assigned. With the inclusion of Plectognathotrema in the Zoogonidae, there are now three zoogonid genera for which the species are restricted to monacanthid teleosts, i.e. Cephaloporus Yamaguti, 1934, Plectognathotrema and Yamagutiplectognathotrema Parukhin, 1977. Species of these genera share pronounced morphological and ecological affinities and a previously synonymised subfamily, the Cephaloporinae Yamaguti, 1934, is resurrected for them. The host specificity of these trematodes is commented upon.  相似文献   

17.
Tooth enamel microstructure is a reliable and widely used indicator of dietary interpretations and data for phylogenetic reconstruction, if all levels of variability are investigated. It is usually difficult to have a thorough examination at all levels of enamel structures for any mammals, especially for the early mammals, which are commonly represented by sparse specimens. Because of the random preservation of specimens, enamel microstructures from different teeth in various species are often compared. There are few examples that convincingly show intraspecific variation of tooth enamel microstructure in full dentition of a species, including multituberculates. Here we present a systematic survey of tooth enamel microstructures of Lambdopsalis bulla, a taeniolabidoid multituberculate from the Late Paleocene Nomogen Formation, Inner Mongolia. We examined enamel structures at all hierarchical levels. The samples are treated differently in section orientations and acid preparation and examined using different imaging methods. The results show that, except for preparation artifacts, the crystallites, enamel types, Schmelzmuster and dentition types of Lambdopsalis are relatively consistent in all permanent teeth, but the prism type, including the prism shape, size and density, may vary in different portions of a single tooth or among different teeth of an individual animal. The most common Schmelzmuster of the permanent teeth in Lambdopsalis is a combination of radial enamel in the inner and middle layers, aprismatic enamel in the outer layer, and irregular decussations in tooth crown area with great curvature. The prism seam is another comparably stable characteristic that may be a useful feature for multituberculate taxonomy. The systematic documentation of enamel structures in Lambdopsalis may be generalized for the enamel microstructure study, and thus for taxonomy and phylogenetic reconstruction, of multituberculates and even informative for the enamel study of other early mammals.  相似文献   

18.
19.
The diversity and physiological characteristics of culturable bacteria associated with lichens from different habitats of the Arctic and Antarctica were investigated. The 68 retrieved isolates could be grouped on the basis of their 16S rRNA gene sequences into 26 phylotypes affiliated with the phyla Actinobacteria, Bacteroidetes, Deinococcus-Thermus, and Firmicutes and with the classes Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. Isolates belonging to the Alphaproteobacteria were the most abundant, followed by those belonging to Actinobacteria, Betaproteobacteria, Gammaproteobacteria, Bacteroidetes, Firmicutes, and Deinococcus-Thermus. Phylogenetic analysis showed that approximately 21 % of the total isolates represented a potentially novel species or genus (≤97 % sequence similarity). Strains belonging to the genera Sphingomonas, Frondihabitans, Hymenobacter, and Burkholderia were recovered from lichen samples from both geographic locations, implying common and important bacterial functions within lichens. Extracellular protease activities were detected in six isolates, affiliated with Burkholderia, Frondihabitans, Hymenobacter, Pseudomonas, and Rhodanobacter. Extracellular lipase activities were detected in 37 isolates of the genera Burkholderia, Deinococcus, Frondihabitans, Pseudomonas, Rhodanobacter, Sphingomonas, and Subtercola. This is the first report on the culturable bacterial diversity present within lichens from Arctic and Antarctica and the isolates described herein are valuable resources to decode the functional and ecological roles of bacteria within lichens. In addition, the low similarity (≤97 %) of the recovered isolates to known species and their production of cold-active enzymes together suggest that lichens are noteworthy sources of novel bacterial strains for use in biotechnological applications.  相似文献   

20.
Collections from French Guiana, Amazonian Brazil, and Colombia taken in the last 20 years include new species in the following genera:Duroia, Pagamea, Psychotria, Randia, Retiniphyllum, Rudgea, Sabicea, Sipanea, andSphinctanthus. Twenty-one new species are described and five are illustrated.  相似文献   

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