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Megadromus guerinii, an endemic carabid beetle (Carabidae), is the most common carabid throughout its restricted range on Banks Peninsula, a formation of extinct volcanoes in Canterbury, New Zealand. This study characterises the small-scale phylogeographic patterns of M. guerinii across the formerly volcanically active Banks Peninsula using mitochondrial and ribosomal genes. Between the eastern and western areas of the peninsula, the mitochondrial, but not nuclear, DNA has a well-defined geographic distribution. Specifically, mitochondrial cytochrome c oxidase subunit I (CO1) identifies two distinct groups (> 6% divergence between eastern and western beetles) while ribosomal genes show no discernible pattern. Whether such a pattern represents male-biased dispersal, Wolbachia infection, a recent range expansion of a divergent lineage, or a deeper historic separation is explored. There is potential that male-biased dispersal could have occurred. Wolbachia infection was not detected. We conclude that historical processes have likely separated taxa in the eastern and western peninsula. 相似文献
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Patterns of chloroplast DNA (cpDNA) and mitochondrial DNA (mtDNA) variation
were studied in 378 populations of oak trees sampled throughout the
southern half of France. Six cpDNA haplotypes detected in a previous
European survey and three new cpDNA haplotypes were found in this region.
Two mitochondrial polymorphisms detected earlier by restriction analysis of
PCR-amplified fragments alone, or in combination with single-strand
conformation polymorphism (SSCP), were compared with the cpDNA data.
Sequencing revealed the nature of the two mitochondrial mutations: a
single-base substitution and a 4-bp inversion associated with a 22-bp
hairpin secondary structure. The single-base substitution was then analyzed
by allele-specific amplification. Results for the two cytoplasmic genomes
were combined, which allowed the identification of 12 cpDNA-mtDNA
haplotypes. The 4-bp mtDNA inversion has appeared independently in
different cpDNA lineages. Given the peculiar nature of this mtDNA mutation,
we suggest that intramolecular recombination leading to repeated inversions
of the 4-bp sequence (rather than paternal leakage of one of the two
genomes) is responsible for this pattern. Furthermore, the geographic
locations of the unusual cpDNA-mtDNA associations (due to the inversion)
usually do not match the zones of contact between divergent haplotypes. In
addition, in southern France, the groupings of populations based on the
mtDNA substitution were strictly congruent with those based on cpDNA.
Because many populations that are polymorphic for both cpDNA and mtDNA have
remained in contact since postglacial recolonization in this area without
producing any new combination of cytoplasms involving the mitochondrial
substitution, we conclude that paternal leakage is not a significant factor
at this timescale. Such results confirm and expand our earlier conclusions
based on controlled crosses.
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The genus Ulkenia is characterized by the naked protoplast stage within its life cycle. However, the 18S rRNA gene tree clearly shows that
this genus is not a natural taxon, because our own isolates and reported strains separately form four well-supported monophyletic
groups. These four groups are clearly distinguishable by their profiles of polyunsaturated fatty acids and carotenoid pigments
and cell and colony morphology, e.g., persistence of sporangial wall, manner of the cell cleavage at the zoospore formation,
and development of the ectoplasmic nets. Therefore, the four groups are assigned to four genera including three new genera,
i.e., Ulkenia sensu stricto, Botryochytrium, Parietichytrium, and Sicyoidochytrium gen. nov. 相似文献
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FM Gür S Timurkaan MH Yalcin A Girgin B Gençer Tarakçı 《Biotechnic & histochemistry》2017,92(4):245-251
Irisin was first identified in skeletal muscle cells. It is an exercise protein that is secreted into the circulation; it causes conversion of white adipose tissue to brown adipose tissue. We investigated irisin immunoreactivity in mole rat (Spalax leucodon) tissues. We examined cerebellum, pituitary, heart, liver, pancreas, spleen, uterus, kidney and striated muscle in female adult mole rats. Tissues were processed, embedded in paraffin, sectioned at 5 μm and stained immunohistochemically for irisin. Irisin immunostaining was detected in the cytoplasm of stained cells; the cytoplasm of Purkinje cells was unstained. We found that irisin may be synthesized in many tissues. The function of locally synthesized irisin currently is unknown. 相似文献
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gamma-aminobutyric acid increases the water accessibility of M3 membrane-spanning segment residues in gamma-aminobutyric acid type A receptors 总被引:3,自引:0,他引:3 下载免费PDF全文
gamma-Aminobutyric acid type A (GABA(A)) receptors are members of the ligand-gated ion channel gene superfamily. Using the substituted cysteine accessibility method, we investigated whether residues in the alpha(1)M3 membrane-spanning segment are water-accessible. Cysteine was substituted, one at a time, for each M3 residue from alpha(1)Ala(291) to alpha(1)Val(307). The ability of these mutants to react with the water-soluble, sulfhydryl-specific reagent pCMBS(-) was assayed electrophysiologically. Cysteines substituted for alpha(1)Ala(291) and alpha(1)Tyr(294) reacted with pCMBS(-) applied both in the presence and in the absence of GABA. Cysteines substituted for alpha(1)Phe(298), alpha(1)Ala(300), alpha(1)Leu(301), and alpha(1)Glu(303) only reacted with pCMBS(-) applied in the presence of GABA. We infer that the pCMBS(-) reactive residues are on the water-accessible surface of the protein and that GABA induces a conformational change that increases the water accessibility of the four M3 residues, possibly by inducing the formation of water-filled crevices that extend into the interior of the protein. Others have shown that mutations of alpha(1)Ala(291), a water-accessible residue, alter volatile anesthetic and ethanol potentiation of GABA-induced currents. Water-filled crevices penetrating into the interior of the membrane-spanning domain may allow anesthetics and alcohol to reach their binding sites and thus may have implications for the mechanisms of action of these agents. 相似文献
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A. terreus isolates isolated from some bakery products, corn and rice were found to be able to produce territrems. 90% of theA. terreus isolated from bakery products were able to produce territrem A, with a mean of 0.09 ppm, while 80% ofA. terreus isolates produce territrem B with a mean of 0.24 ppm. On the other hand 31.8% of the isolates ofA. terreus from corn were able to produce territrem A with a mean of 0.44 ppm. ConcerningA. terreus isolates from rice, 66.7% were found to produce territrem A, with a mean of 5.28 ppm, and 77.8% of the isolates produced
territrem B with a mean of 1.79 ppm. 相似文献
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Hilde MH Braakman Jan Lodder Alida A Postma Lambert FR Span Werner H Mess 《BMC neurology》2010,10(1):30