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71.
72.
Caird Rexroad Roger Vallejo Issa Coulibaly Charlene Couch Amber Garber Mark Westerman Craig Sullivan 《Conservation Genetics》2006,7(6):971-982
Striped bass (Morone saxatilis) is economically important in the US due to its value as an aquaculture species and in supporting commercial and recreational fisheries, especially those off the Atlantic coast and in the Gulf of Mexico. Modern strategies for managing fishery populations and aquaculture broodstocks employ the use of molecular genetic markers to identify individuals, assign parentage, and characterize population genetic structure and levels of inbreeding and migration. As part of a collaborative effort to utilize molecular genetic technologies in striped bass breeding programs we generated microsatellite markers for use in population genetic studies, broodstock selection and management strategies, and the construction of a genetic map. We developed 345 new microsatellite markers for striped bass, a subset (n=71) of which was characterized by genotyping samples from two striped bass broodstock populations to evaluate marker polymorphism, percent heterozygosity, Hardy–Weinberg equilibrium (HWE), linkage disequilibrium (LD) and utility for population genetic studies. 相似文献
73.
Influence of selenium on toxicity of some heavy metals in the green algaScenedesmus obliquus 总被引:1,自引:0,他引:1
The green alga Scenedesmus obliquus was incubated with heavy metals (Cd2+, Zn2+, Mn2+, Ni2+) with and without selenium. S. obliquus exhibited higher rates of growth and some metabolic activities in cultures containing 0.1 mmol/L Se than those only containing the heavy metals. The positive effect of Se was found with all metals but was negligible with Mn2+. 相似文献
74.
Effects of the inoculation of cyanobacteria on the microstructure and the structural stability of a tropical soil 总被引:3,自引:0,他引:3
Oumarou Malam Issa Christian Défarge Yves Le Bissonnais Béatrice Marin Odile Duval Ary Bruand Luigi Paolo D’Acqui Sofie Nordenberg Marcus Annerman 《Plant and Soil》2007,290(1-2):209-219
Cyanobacteria are widespread photosynthetic microorganisms among which some are able to fix atmospheric nitrogen. We investigated
the impact of indigenous cyanobacteria strains (Nostoc) inoculation on physical characteristics of poorly aggregated soils from Guquka (Eastern Cape, South Africa). The soil aggregates
(3–5 mm) were arranged into a layer of 10–20 mm thick, and sprayed with cyanobacteria solution. Subsequently the inoculated
and un-inoculated samples were incubated (30°C, 80% humidity, continuous illumination at 100 μmol m−2 s−1). Their micromorphological characteristics and aggregate stability were investigated, after 1, 2, 3, 4 and 6 weeks of incubation,
by using high resolution Cryo-SEM and aggregate breakdown tests.
Micromorphological investigations revealed that the surface of un-inoculated samples remained uncovered, while the inoculated
samples were partially covered by cyanobacteria material after one week of incubation. A dense superficial network of cyanobacterial
filaments and extracellular polymer secretions (EPS) covered their surface after 4 and 6 weeks of incubation. Organo-mineral
aggregates comprising cyanobacterial filaments and EPS were observed after 6 weeks of incubation. The results of aggregate
breakdown tests showed no significant difference between un-inoculated samples after 1, 2, 3, 4 or 6 weeks, while they revealed
improvement of aggregate stability for inoculated samples. The improvement of aggregate stability appeared in a short while
following inoculation and increased gradually with time and cyanobacteria growth. The increase in aggregate stability is likely
related to the changes induced in micromorphological characteristics by cyanobacterial filaments and EPS. It reflects the
effect of coating, enmeshment, binding and gluing of aggregates and isolated mineral particles by cyanobacteria material.
Our study presents new data demonstrating the improvement of soil physical quality in a few weeks after cyanobacteria inoculation.
The interaction of the inocula and other biotic components is worthy of study before field application of cyanobacteria. 相似文献
75.
Isolation and Characterization of Polycyclic Aromatic Hydrocarbon–Degrading Mycobacterium Isolates from Soil 总被引:5,自引:0,他引:5
Miller CD Hall K Liang YN Nieman K Sorensen D Issa B Anderson AJ Sims RC 《Microbial ecology》2004,48(2):230-238
Bioremediation of soils contaminated with wood preservatives containing polycyclic aromatic hydrocarbons (PAHs) is desired because of their toxic, mutagenic, and carcinogenic properties. Creosote wood preservative–contaminated soils at the Champion International Superfund Site in Libby, Montana currently undergo bioremediation in a prepared-bed land treatment unit (LTU) process. Microbes isolated from these LTU soils rapidly mineralized the 14C-labeled PAH pyrene in the LTU soil. Gram staining, electron microscopy, and 16S rDNA-sequencing revealed that three of these bacteria, JLS, KMS, and MCS, were Mycobacterium strains. The phylogeny of the 16S rDNA showed that they were distinct from other Mycobacterium isolates with PAH-degrading activities. Catalase and superoxide dismutase (SOD) isozyme profiles confirmed that each isolate was distinct from each other and from the PAH-degrading mycobacterium, Mycobacterium vanbaalenii sp. nov, isolated from a petroleum-contaminated soil. We find that dioxygenase genes nidA and nidB are present in each of the Libby Mycobacterium isolates and are adjacent to each other in the sequence nidB-nidA, an order that is unique to the PAH-degrading mycobacteria.This revised version was published online in November 2004 with corrections to Volume 48. 相似文献
76.
77.
Louis JM Nesheiwat I Chang L Clore GM Bewley CA 《The Journal of biological chemistry》2003,278(22):20278-20285
We have engineered two soluble, covalently linked, trimeric polypeptides, N35CCG-N13 and N34CCG comprising only the internal trimeric coiled-coil of the ectodomain of HIV-1 gp41. Both trimers inhibit human immunodeficiency virus, type 1 (HIV-1) envelope (Env)-mediated cell fusion at nanomolar concentrations by targeting the exposed C-terminal region of the gp41 ectodomain in the prehairpin intermediate state. The IC50 values for N35CCG-N13 and N34CCG are approximately 15 and approximately 95 nM, respectively, in a quantitative vaccinia virus-based reporter gene assay for HIV-1 Env-mediated cell fusion using Env from the T cell tropic strain LAV. Polyclonal antibodies were raised against N35CCG-N13 and a tightly binding fraction of anti-N35CCG-N13 inhibits T cell and macrophage tropic HIV-1 Env-mediated cell fusion with respective IC50 values of approximately 0.5 and approximately 1.5 microg/ml at 37 degrees C. The tightly binding anti-N35CCG-N13 antibody fraction targets the exposed internal trimeric coiled-coil in the prehairpin intermediate state of gp41 in a manner analogous to peptides derived from the C region of the gp41 ectodomain. The potency of the tightly binding anti-N35CCG-N13 antibody fraction in the fusion assay is comparable with that of the broadly neutralizing monoclonal antibody 2G12. These results indicate that N35CCG-N13 is a potential anti-HIV therapeutic agent and represents a suitable immunogen for the generation of neutralizing monoclonal antibodies targeted to the internal trimeric coiled-coil of gp41. The data on the tightly binding anti-N35CCG-N13 antibody fraction demonstrate that the internal trimeric coiled-coil of gp41 in the prehairpin intermediate state is accessible to antibodies and that access is not restricted by either antibody size or the presence of a kinetic barrier. 相似文献
78.
El-Shemy HA Aboul-Enein AM Aboul-Enein MI Issa SI Fujita K 《Journal of biochemistry and molecular biology》2003,36(4):387-389
The young developing leaves of willow (Salix safsaf, Salicaceae) trees have antileukemic activity. After a 24-h incubation in vitro, the crude water extracts of the leaves killed a majority of the blasts of acute myeloid leukemia (AML, 73.8%). 相似文献
79.
Substitution bias, rapid saturation, and the use of mtDNA for nematode systematics 总被引:13,自引:0,他引:13
Only relatively recently have researchers turned to molecular methods for
nematode phylogeny reconstruction. Thus, we lack the extensive literature
on evolutionary patterns and phylogenetic usefulness of different DNA
regions for nematodes that exists for other taxa. Here, we examine the
usefulness of mtDNA for nematode phylogeny reconstruction and provide data
that can be used for a priori character weighting or for parameter
specification in models of sequence evolution. We estimated the
substitution pattern for the mitochondrial ND4 gene from intraspecific
comparisons in four species of parasitic nematodes from the family
Trichostrongylidae (38-50 sequences per species). The resulting pattern
suggests a strong mutational bias toward A and T, and a lower
transition/transversion ratio than is typically observed in other taxa. We
also present information on the relative rates of substitution at first,
second, and third codon positions and on relative rates of saturation of
different types of substitutions in comparisons ranging from intraspecific
to interordinal. Silent sites saturate extremely quickly, presumably owing
to the substitution bias and, perhaps, to an accelerated mutation rate.
Results emphasize the importance of using only the most closely related
sequences in order to infer patterns of substitution accurately for
nematodes or for other taxa having strongly composition-biased DNA. ND4
also shows high amino acid polymorphism at both the intra- and
interspecific levels, and in higher level comparisons, there is evidence of
saturation at variable amino acid sites. In general, we recommend using
mtDNA coding genes only for phylogenetics of relatively closely related
nematode species and, even then, using only nonsynonymous substitutions and
the more conserved mitochondrial genes (e.g., cytochrome oxidases). On the
other hand, the high substitution rate in genes such as ND4 should make
them excellent for population genetics studies, identifying cryptic
species, and resolving relationships among closely related congeners when
other markers show insufficient variation.
相似文献
80.
Phylogeny of the Drosophila saltans species group based on combined analysis of nuclear and mitochondrial DNA sequences 总被引:2,自引:0,他引:2
Nucleotide sequences from two nuclear loci, alcohol dehydrogenase and
internal transcribed spacer-1 of the nuclear ribosomal DNA repeats, and two
mitochondrial genes, cytochrome oxidase I and cytochrome oxidase II, were
determined from nine species in the Drosophila saltans species group. The
partition homogeneity test and partitioned Bremer support were used to
measure incongruence between phylogenetic hypotheses generated from
individual partitions. Individual loci were generally congruent with each
other and consistent with the previously proposed morphological hypothesis,
although they differed in level of resolution. Since extreme conflict
between partitions did not exist, the data were combined and analyzed
simultaneously. The total evidence method gave a more resolved and highly
supported phylogeny, as indicated by bootstrap proportions and decay
indices, than did any of the individual analyses. The cordata and elliptica
subgroups, considered to have diverged early in the history of the D.
saltans group, were sister taxa to the remainder of the saltans group. The
sturtevanti subgroup, represented by D. milleri and D. sturtevanti,
occupies an intermediate position in this phylogeny. The saltans and
parasaltans subgroups are sister clades and occupy the most recently
derived portion of the phylogeny. As with previous morphological studies,
phylogenetic relationships within the saltans subgroup were not
satisfactorily resolved by the molecular data.
相似文献