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31.
Rebecca C Mueller Fabiana S Paula Babur S Mirza Jorge LM Rodrigues Klaus Nüsslein Brendan JM Bohannan 《The ISME journal》2014,8(7):1548-1550
Understanding the interactions among microbial communities, plant communities and soil properties following deforestation could provide insights into the long-term effects of land-use change on ecosystem functions, and may help identify approaches that promote the recovery of degraded sites. We combined high-throughput sequencing of fungal rDNA and molecular barcoding of plant roots to estimate fungal and plant community composition in soil sampled across a chronosequence of deforestation. We found significant effects of land-use change on fungal community composition, which was more closely correlated to plant community composition than to changes in soil properties or geographic distance, providing evidence for strong links between above- and below-ground communities in tropical forests. 相似文献
32.
33.
Bendia Amanda G. Araujo Gabriel G. Pulschen André A. Contro Bruna Duarte Rubens T. D. Rodrigues Fábio Galante Douglas Pellizari Vivian H. 《Extremophiles : life under extreme conditions》2018,22(6):917-929
Extremophiles - Polar volcanoes harbor unique conditions of extreme temperature gradients capable of selecting different types of extremophiles. Deception Island is a marine stratovolcano located... 相似文献
34.
Three satellite DNA families were identified in three species of burying
beetles, Nicrophorus orbicollis, N. marginatus, and N. americanus. Southern
hybridization and nucleotide sequence analysis of individual randomly
cloned repeats shows that these satellite DNA families are highly abundant
in the genome, are composed of unique repeats, and are species-specific.
The repeats do not have identifiable core elements or substructures that
are similar in all three families, and most interspecific sequence
similarity is confined to homopolymeric runs of A and T. Satellite DNA from
N. marginatus and N. americanus show single-base-pair indels among repeats,
but single-nucleotide substitutions characterize most of the repeat
variability. Although the repeat units are of similar lengths (342, 350,
and 354 bp) and A + T composition (65%, 71%, and 71%, respectively), the
average nucleotide divergence among sequenced repeats is very low (0.18%,
1.22%, and 0.71%, respectively). Transition/transversion ratios from the
consensus sequence are 0.20, 0.69, and 0.70, respectively.
相似文献
35.
The yeast ATP synthase subunit 4: structure and function 总被引:1,自引:0,他引:1
The structure of ATP synthase subunit 4 was determined by using the oligonucleotide probe procedure. This subunit is the fourth polypeptide of the complex when classifying subunits in order of decreasing molecular mass. Its relative molecular mass is 25 kDa. The ATP4 gene was isolated and sequenced. The nucleotide sequence predicts that subunit 4 is probably derived from a precursor protein 244 amino acids long. Mature subunit 4 contains 209 amino acid residues and the predicted molecular mass is 23250 kDa. Subunit 4 shows homology with the b-subunit of Escherichia coli ATP synthase and the b-subunit of beef heart mitochondrial ATP synthase. By using homologous transformation, a mutant lacking wild subunit 4 was constructed. This mutant is devoid of oxidative phosphorylation and F1 is loosely bound to the membrane. Our data are in favor of a structural relationship between subunit 4 and the mitochondrially-translated subunit 6 during biogenesis of F0. 相似文献
36.
D Galante S Esposito D Barba C Scioli 《Bollettino della Società italiana di biologia sperimentale》1983,59(11):1678-1682
54 beta-lactamase producing E. coli were tested to observe their eventual capacity to transfer beta-lactamase production by conjugation to a receiving E. coli K12 C600 Na-. About 16% (9/54) of these strains transferred beta-lactamase producing capacity. MICs of five beta-lactam antibiotics (Ampicillin, Cephaloridine, Cephalexine, Cefuroxime, Cefotaxime) were performed against E. coli donors and E. coli K12 C600 transconjugates. It was observed a remarkable increase only of Ampicillin MICs against all transconjugates++. Beta-lactamases produced by donors and transconjugants were isolated and purified by sonication and high speed centrifugation. Sensitivity of the six antibiotics to these purified beta-lactamases was assessed by a spectrophotometric method that utilizes the velocity of cytochrome c reduction. beta-lactamases produced by transconjugants have identical substrate profile that beta-lactamases produced by donors. 相似文献
37.
Membrane resistance change of the frog taste cells in response to water and Nacl 总被引:2,自引:0,他引:2
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The electrical properties of the frog taste cells during gustatory stimulations with distilled water and varying concentrations of NaCl were studied with intracellular microelectrodes. Under the Ringer adaptation of the tongue, two types of taste cells were distinguished by the gustatory stimuli. One type, termed NaCl-sensitive (NS) cells, responded to water with hyperpolarizations and responded to concentrated NaCl with depolarizations. In contrast, the other type of cells, termed water-sensitive (WS) cells, responded to water depolarizations and responded to concentrated NaCl with hyperpolarizations. The membrane resistance of both taste cell types increased during the hyperpolarizing receptor potentials and decreased during the depolarizing receptor potentials, Reversal potentials for the depolarizing and hyperpolarizing responses in each cell type were a few millivolts positive above the zero membrane potential. When the tongue was adapted with Na-free Ringer solution for 30 min, the amplitude of the depolarizing responses in the NS cells reduced to 50% of the control value under normal Ringer adaptation. On the basis of the present results, it is concluded (a) that the depolarizing responses of the NS and WS cells under the Ringer adaptation are produced by the permeability increase in some ions, mainly Na+ ions across the taste cell membranes, and (b) that the hyperpolarizing responses of both types of taste cells are produced by a decrease in the cell membrane permeability to some ions, probably Na+ ions, which is slightly enhanced during the Ringer adaptation. 相似文献
38.
Mitochondrial ATP-Pi exchange complex 总被引:4,自引:0,他引:4
Y Hatefi D L Stiggall Y Galante W G Hanstein 《Biochemical and biophysical research communications》1974,61(1):313-321
An enzyme complex with high ATP-Pi exchange activity has been purified from beef heart mitochondria, using the general procedure which also yields electron transfer complexes I, II, III and IV from the same batch of mitochondria. The ATP-Pi exchange activity of the preparation, designated complex V, is inhibited by various uncouplers, rutamycin, venturicidin, dicyclohexylcarbodiimide, arsenate, azide, adenylyl imidodiphosphate, and valinomycin plus potassium. The ATP-Pi exchange activity of complex V is specific with respect to ATP; ITP, GTP and UTP are essentially ineffective. Complex V is deficient in cytochromes, but 2–3 times enriched as compared to mitochondria with respect to binding sites for the uncoupler 2-azido-4-nitrophenol. As in mitochondria, this binding is competitively inhibited by other uncouplers. Complexes I, III and IV, which in mitochondria contain the three energy coupling sites, do not bind the above uncoupler. 相似文献
39.
Molecular evidence for the rapid propagation of mouse t haplotypes from a single, recent, ancestral chromosome 总被引:11,自引:0,他引:11
Silver LM; Hammer M; Fox H; Garrels J; Bucan M; Herrmann B; Frischauf AM; Lehrach H; Winking H; Figueroa F 《Molecular biology and evolution》1987,4(5):473-482
Mouse t haplotypes are variant forms of chromosome 17 that exist at high
frequencies in worldwide populations of two species of commensal mice. To
determine both the relationship of t haplotypes to each other and the
species within which they exist, 35 representative t haplotypes were
analyzed by means of 10 independent molecular probes, including five DNA
clones and five polypeptide spots identified by means of two- dimensional
gel electrophoresis. All of the tested haplotypes were found to share
restriction fragments and polypeptide spots that are absent in mice
carrying wild-type forms of chromosome 17. This observation provides the
first direct evidence that all of the known t haplotypes are descendents of
a single ancestral chromosome. The absence of variation among t haplotypes
could mean that this ancestral chromosome existed relatively recently, in
which case it would be necessary to postulate introgressions of t
haplotypes across species lines to explain their presence in both Mus
domesticus and M. musculus. Alternatively, it is possible that the
ancestral chromosome existed prior to the split between M. domesticus and
M. musculus and that, by chance, our probes fail to detect polymorphisms
that exist among the t haplotypes. A further result of our analysis is the
characterization of a partial t haplotype in a wild population of Israeli
mice.
相似文献
40.