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101.
Saswati Nayak Radha Prasanna Boddupalli M. Prasanna Dina B. Sahoo 《World journal of microbiology & biotechnology》2007,23(11):1575-1584
A set of 24 strains belonging to the genus Anabaena (Phylum Cyanobacteria), isolated from diverse geographic locations in India, were evaluated along with three International
type strains of Anabaena (ATCC 29414, ATCC 29208 and ATCC 27899) for their morphological, physiological and biochemical diversity. The morphological
dataset, consisting of 58 variants for 15 characters, and SDS-PAGE protein profiles comprising 17 polymorphic bands were utilized
to differentiate the selected Anabaena strains and explore the patterns of diversity through cluster analysis. Physiological and biochemical characterization with
respect to nitrogen fixation and accumulation of chlorophyll and phycobiliproteins led to the identification of some highly
promising Anabaena strains for use as biofertilizers and source of pigments. The study highlighted the tremendous inter and intraspecific diversity
within the Anabaena isolates and indicated the potential as well as constraints of the morphological and protein profiling datasets for unambiguous
differentiation and analyses of diversity among the Anabaena strains. 相似文献
102.
At the edges of tropical rain forest fragments, altered abiotic and biotic conditions influence the structure and dynamics
of plant communities. In Neotropical rain forests, palms (Arecaceae) are important floristic and ecological elements. Palms’
responses to edge effects appear to be idiosyncratic and to depend on the level of disturbance at edges. This paper explores
how variation in forest structure at the edges of two old-growth forest fragments in a tropical rain forest in western Ecuador
affects palms of different species, life-forms, and size classes. We investigate (1) how edge effects influence the relative
proportion of palm adults and juveniles, (2) how distance from the forest edge affects palm density and species richness,
(3) how altered forest structure along edges affects palm density. We found that at edges (1) palm communities had a lower
proportion of adults relative to juvenile individuals compared to continuous forests, (2) the density of two species of palms
and the overall species richness of the palm community tended to decrease toward the edges within forest fragments, and, (3)
altered forest structure decreased the density of adult palms. Hence, edge effects on palms were controlled by the degree
of modification of the forest structure, and by species responses to edge-related disturbance. 相似文献
103.
We investigated the distribution pattern of centipedes (Chilopoda) in four primeval forests of the western Carpathians, central
Slovakia. The forests are located in two different mountain ranges (Kremnické vrchy and Pol’ana Mountains), which are exposed
on either the southern (Boky, Rohy) or northern slopes (Pol’ana, Badín). In these forests, the influence of coarse woody debris
(CWD) on centipede distribution was studied, by distinguishing sampling sites on the forest floor, close to CWD (c-CWD) and
distant from CWD (d-CWD). In total, we collected 2,706 individuals from 20 species of centipedes. Average species richness
and number of individuals per forest ranged from 8 to 12 species/m2 and from 244 to 486 individuals/m2. The oak forests on south facing slopes harboured several species, which did not occur in the more northern exposed fir-beech
forests. Number of species as well as individuals, however, varied more within than between individual forests. Increase of
species number and density was mainly caused by CWD and was more pronounced on the southern slopes (P<0.001), characterized by high temperatures and low precipitation, than on the northern slopes (n.s. to P<0.01), characterized by low temperatures and high precipitation. It was found that CWD did not generally increase (species)
diversity. 相似文献
104.
The conservation of Himalayan forests is big concern in view of global agenda. Many studies in this endeavor reported that
the rate of forests degradation is posing a severe threat to the landscape and existing biodiversity in the Himalayas. Currently
there many conservation approaches exists and of them four are widely recognized (1) Conservation through traditional religious
beliefs “traditional conserved forests” (TCF); (2) Conservation through governmental planning and schemes “government conserved
forests” (GCF); (3) Conservation through creation of protected areas (PAF); and (4) Conservation through community efforts
“community conserved forests” (CCF). Our hypothesis in this direction says that all the conservation approaches lead to same
results concerning to forest conservation. To testify our hypothesis we have studied the forests of each conservation regimes
and evaluated them based on the identified indicators. We have done empirical studies and following the cloud-free satellite
data were used for last three decades (such as Multi-Spectral Scanner, Linear Imaging and Self Scanning, and Enhanced Thematic
Mapper ) to study a change in vegetation dynamics of the mountain forests in multi-temporal dimension. Our research concluded
that community conservation approach have greater significance for biodiversity conservation and management in the Himalayan
region. Here we support the model of CCF for forest ecosystem conservation, alongside the sustainable livelihood of the mountain
societies. But every conservation regimes has its own importance in viewpoint of the particular objectives. Therefore, we
suggests advancement and revision of PAF and GCF however, some elements of CCF can be introduced in TCF for making up it more
sound in view of rapid socio-economic and cultural changes taking place in the communities.
An erratum to this article can be found at 相似文献
105.
Emiliano Ukmar Corrado Battisti Luca Luiselli Marco A. Bologna 《Biodiversity and Conservation》2007,16(12):3287-3300
Breeding bird communities in burnt and unburnt residual pinewoods were studied over 3 years by line-transect method, following
a catastrophic fire event in Castelfusano (Rome, Central Italy; July 2000). We applied bootstrap procedures to evaluate whether
the observed data were true or just produced by chance, and then examined the emerging patterns at three levels: community,
guild and species levels. At the community level, fire acted on breeding bird communities by altering especially the total
abundance patterns: the species abundance decreased in the burnt pinewood compared to the residual one, but other parameters
were not significantly affected by fire. As a consequence of fire, the destruction and structural simplification of the canopy
and shrubby component, as well as the increase of edge habitat and patchiness at landscape scale, induced a turnover in species
between pinewoods. Species turnover was higher at the burnt than at the residual pinewoods, during all the 3 years of study.
At the guild level, the forest species decreased strongly in terms of richness and abundance in the burnt pinewoods, contrary
to the edge and open habitat species which increased in terms of richness, abundance and evenness. Edge species showed the
highest turnover in burnt pinewood during the whole period of study. At species level, after an a priori subdivision (based
on bibliographic search) of the various species in two ecological guilds (forest versus edge species), it was found that an
a posteriori statistical analysis confirmed the expected trend, i.e. that the species which decreased significantly in burnt
pinewood were essentially the forest species, whereas the species which increased were essentially the edge/open habitat ones.
Overall, in order to investigate the effects of fire catastrophes on birds, the guild approach seems more exhaustive than
the taxonomic community approach, where intrinsic confounding trends are present. 相似文献
106.
Spiroplasma species in the Costa Rican highlands: implications for biogeography and biodiversity 总被引:1,自引:0,他引:1
Robert F. Whitcomb Joseph G. Tully Gail E. Gasparich Laura B. Regassa David L. Williamson Frank E. French 《Biodiversity and Conservation》2007,16(13):3877-3894
More than 1,000 Spiroplasma isolates have been obtained from horse flies and deer flies (Diptera:Tabanidae) in the United States and Canada. However, the spiroplasma biota of Central America is poorly known. In August of 1995 and
1998, 13 isolates were obtained in 14 attempts from horse flies of a single species, Poeciloderas quadripunctatus, taken in the Costa Rican highlands (1,100–2,000 m). The majority of the “isolates” proved to be mixtures of two or more
Spiroplasma species, but after filter cloning, single strains emerged that were designated as representatives of the 13 accessions. Six
distinct spiroplasma serogroups were identified from these isolations. Three of the strains are putative new species with
no serological relationship to any other Spiroplasma species. A fourth strain is a putative new species that may be distantly related to S. helicoides, a southeastern U.S. species. These four strains are accorded herein status as representatives of new serogroups: strain
BARC 4886 (group XXXV); strain BARC 4900 (group XXXVI); strain BARC 4908 (group XXXVII); and GSU5450 (group XXXVIII). A fifth
Spiroplasma species was very closely related to S. lineolae, known previously only from the Georgia (U.S.) coast. The sixth was most closely related to subgroup VIII-3, known from Texas
and the southeastern U.S. Discovery of six spiroplasma species in only 13 attempted isolations reflects diversity seldom equaled
in southeast Georgia, and never elsewhere in the U.S. These results are consistent with a hypothesis that spiroplasma diversity
increases from north (Nova Scotia) to south (Georgia and Costa Rica). The discovery of significant affinity between some spiroplasmas
of the southeastern U.S. and the Costa Rican highlands was unexpected, but may reflect a climatically complex Pleistocene
history.
相似文献
Robert F. WhitcombEmail: |
107.
Takishita K Yubuki N Kakizoe N Inagaki Y Maruyama T 《Extremophiles : life under extreme conditions》2007,11(4):563-576
Recent culture-independent surveys of eukaryotic small-subunit ribosomal DNA (SSU rDNA) from many environments have unveiled
unexpectedly high diversity of microbial eukaryotes (microeukaryotes) at various taxonomic levels. However, such surveys were
most probably biased by various technical difficulties, resulting in underestimation of microeukaryotic diversity. In the
present study on oxygen-depleted sediment from a deep-sea methane cold seep of Sagami Bay, Japan, we surveyed the diversity
of eukaryotic rDNA in raw sediment samples and in two enrichment cultures. More than half of all clones recovered from the
raw sediment samples were of the basidiomycetous fungus Cryptococcus curvatus. Among other clones, phylotypes of eukaryotic parasites, such as Apicomplexa, Ichthyosporea, and Phytomyxea, were identified.
On the other hand, we observed a marked difference in phylotype composition in the enrichment samples. Several phylotypes
belonging to heterotrophic stramenopiles were frequently found in one enrichment culture, while a phylotype of Excavata previously
detected at a deep-sea hydrothermal vent dominated the other. We successfully established a clonal culture of this excavate
flagellate. Since these phylotypes were not identified in the raw sediment samples, the approach incorporating a cultivation
step successfully found at least a fraction of the “hidden” microeukaryotic diversity in the environment examined.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
108.
Leuko S Goh F Allen MA Burns BP Walter MR Neilan BA 《Extremophiles : life under extreme conditions》2007,11(1):203-210
Hamelin Pool in Western Australia is one of the two major sites in the world with active marine stromatolite formation. Surrounded
by living smooth and pustular mats, these ancient laminated structures are associated with cyanobacterial communities. Recent
studies have identified a wide diversity of bacteria and archaea in this habitat. By understanding and evaluating the microbial
diversity of this environment we can obtain insights into the formation of early life on Earth, as stromatolites have been
dated in the geological record as far back as 3.5 billion years. Automated ribosomal intergenic spacer analysis (ARISA) patterns
were shown to be a useful method to genetically discriminate halophilic archaea within this environment. Patterns of known
halophilic archaea are consistent, by replicate analysis, and the halophilic strains isolated from stromatolites have novel
intergenic spacer profiles. ARISA–PCR, performed directly on extracted DNA from different sample sites, provided significant
insights into the extent of previous unknown diversity of halophilic archaea within this environment. Cloning and sequence
analysis of the spacer regions obtained from stromatolites confirmed the novel and broad diversity of halophilic archaea in
this environment. 相似文献
109.
《Systematic and applied microbiology》2022,45(1):126280
Chamaecrista mimosoides is an annual herb legume widely distributed in tropical and subtropical Asia and Africa. It may have primitive and independently-evolved root nodule types but its rhizobia have not been systematically studied. Therefore, in order to learn the diversity and species affinity of its rhizobia, root nodules were sampled from C. mimosoides plants growing in seven geographical sites along the coast line of Shandong Peninsula, China. A total of 422 rhizobial isolates were obtained from nodules, and they were classified into 28 recA haplotypes. By using multilocus sequence analysis of the concatenated housekeeping genes dnaK, glnII, gyrB, recA and rpoB, the representative strains for these haplotypes were designated as eight defined and five candidate novel genospecies in the genus Bradyrhizobium. Bradyrhizobium elkanii and Bradyrhizobium ferriligni were predominant and universally distributed. The symbiotic genes nodC and nifH of the representative strains showed very similar topology in their phylogenetic trees indicating their co-evolution history. All the representative strains formed effective root nodules in nodulation tests. The correlation between genospecies and soil characteristics analyzed by CANOCO software indicated that available potassium (AK), organic carbon (OC) and available nitrogen (AN) in the soil samples were the main factors affecting the distribution of the symbionts involved in this current study. The study is the first systematic survey of Chamaecrista mimosoides-nodulating rhizobia, and it showed that Chamaecrista spp. were nodulated by bradyrhizobia in natural environments. In addition, the host spectrum of the corresponding rhizobial species was extended, and the study provided novel information on the biodiversity and biogeography of rhizobia. 相似文献
110.