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941.
942.
Sweet vernal grasses (Anthoxanthum) colonized African mountains along two fronts in the Late Pliocene,followed by secondary contact,polyploidization and local extinction in the Pleistocene 下载免费PDF全文
Felly Mugizi Tusiime Abel Gizaw Tigist Wondimu Catherine Aloyce Masao Ahmed Abdikadir Abdi Vincent Muwanika Pavel Trávníček Sileshi Nemomissa Magnus Popp Gerald Eilu Manuel Pimentel 《Molecular ecology》2017,26(13):3513-3532
High tropical mountains harbour remarkable and fragmented biodiversity thought to a large degree to have been shaped by multiple dispersals of cold‐adapted lineages from remote areas. Few dated phylogenetic/phylogeographic analyses are however available. Here, we address the hypotheses that the sub‐Saharan African sweet vernal grasses have a dual colonization history and that lineages of independent origins have established secondary contact. We carried out rangewide sampling across the eastern African high mountains, inferred dated phylogenies from nuclear ribosomal and plastid DNA using Bayesian methods, and performed flow cytometry and AFLP (amplified fragment length polymorphism) analyses. We inferred a single Late Pliocene western Eurasian origin of the eastern African taxa, whose high‐ploid populations in one mountain group formed a distinct phylogeographic group and carried plastids that diverged from those of the currently allopatric southern African lineage in the Mid‐ to Late Pleistocene. We show that Anthoxanthum has an intriguing history in sub‐Saharan Africa, including Late Pliocene colonization from southeast and north, followed by secondary contact, hybridization, allopolyploidization and local extinction during one of the last glacial cycles. Our results add to a growing body of evidence showing that isolated tropical high mountain habitats have a dynamic recent history involving niche conservatism and recruitment from remote sources, repeated dispersals, diversification, hybridization and local extinction. 相似文献
943.
944.
Microdissected region-specific gene expression analysis with methacarn-fixed, paraffin-embedded tissues by real-time RT-PCR. 总被引:5,自引:0,他引:5
Hironori Takagi Makoto Shibutani Natsumi Kato Haruka Fujita Kyoung-Youl Lee Shu Takigami Kunitoshi Mitsumori Masao Hirose 《The journal of histochemistry and cytochemistry》2004,52(7):903-913
We have previously shown methacarn to be a versatile fixative for analysis of proteins, DNA, and RNA in paraffin-embedded tissues (PETs). In this study we analyzed its suitability for quantitative mRNA expression analysis of microdissected PET specimens using a real-time RT-PCR technique. Fidelity of expression in the methacarn-fixed PET sections, with reference to dose-dependent induction of cytochrome P450 2B1 in the phenobarbital-treated rat liver, was high in comparison with the unfixed frozen tissue case, even after hematoxylin staining. RNA yield from methacarn-fixed PET sections was equivalent to that in unfixed cryosections and was also not significantly affected by hematoxylin staining. Correlations between the expression levels of target genes and input amounts of extracted RNA in the range of 1-1000 pg were very high (correlation coefficients >0.98), the regression curves being similar to those with unfixed cryosections. Although cell numbers should be optimized for each target gene/tissue, >/=200 cells were necessary for accurate measurement in 10-microm-thick rat liver sections judging from the variation of measured value in small microdissected areas. These results indicate high performance with methacarn, close to that of unfixed tissues, regarding quantitative expression analysis of mRNAs in microdissected PET-specimens. 相似文献
945.
Tetsuya Tatsumi Natsuya Keira Kazuko Akashi Miyuki Kobara Satoaki Matoba Jun Shiraishi Satoshi Yamanaka Akiko Mano Mitsuo Takeda Susumu Nishikawa Jun Asayama Henry Fliss Masao Nakagawa 《Journal of applied physiology》2004,96(3):853-860
The mechanisms by which endotoxemia causes cardiac depression have not been fully elucidated. The present study examined the involvement of nitric oxide (NO) in this pathology. Rats were infused with lipopolysaccharide (LPS) or saline, and the plasma and myocardial NO(2)(-) and NO(3)(-) (NOx) concentrations were measured before or 3, 6, and 24 h after treatment. The hearts were then immediately isolated and mounted in a Langendorff apparatus, and left ventricular developed pressure (LVDP) was determined before biochemical analysis of the myocardium. LPS injection effected the expression of inducible NO synthase (iNOS) in the myocardium, a marked increase in plasma and myocardial NOx levels, and a significant decline in LVDP compared with saline controls. The LPS-induced NO production and concomitant cardiac depression were most pronounced 6 h after LPS injection and were accompanied by a significant increase in myocardial cGMP content. Myocardial ATP levels were not significantly altered after LPS injection. Significant negative correlation was observed between LVDP and myocardial cGMP content, as well as between LVDP and plasma NOx levels. Aminoguanidine, an inhibitor of iNOS, significantly attenuated the LPS-induced NOx production and contractile dysfunction. Furthermore, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, an inhibitor of soluble guanylate cyclase, significantly decreased myocardial cGMP content and attenuated the contractile depression, although aminoguanidine or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one was not able to completely reverse myocardial dysfunction. Our data suggest that endotoxin-induced contractile dysfunction in rat hearts is associated with NO production by myocardial iNOS and a concomitant increase in myocardial cGMP. 相似文献
946.
Detection of Bacteria Carrying the stx2 Gene by In Situ Loop-Mediated Isothermal Amplification 总被引:7,自引:0,他引:7 下载免费PDF全文
Fumito Maruyama Takehiko Kenzaka Nobuyasu Yamaguchi Katsuji Tani Masao Nasu 《Applied microbiology》2003,69(8):5023-5028
A new in situ DNA amplification technique for microscopic detection of bacteria carrying a specific gene is described. Loop-mediated isothermal amplification (LAMP) was used to detect stxA2 in Escherichia coli O157:H7 cells. The mild permeabilization conditions and low isothermal temperature used in the in situ LAMP method caused less cell damage than in situ PCR. It allowed use of fluorescent antibody labeling in the bacterial mixture after the DNA amplification for identification of E. coli O157:H7 cells with an stxA2 gene. Higher-contrast images were obtained with this method than with in situ PCR. 相似文献
947.
Gravitropic response plays an important role in the nutational movements of the shoots of Pharbitis nil and Arabidopsis thaliana 总被引:1,自引:0,他引:1
Yasuko Hatakeda Motoshi Kamada Nobuharu Goto Hidehiro Fukaki Masao Tasaka Hiroshi Suge Hideyuki Takahashi 《Physiologia plantarum》2003,118(3):464-473
The shoots of a Japanese strain of morning glory ( Pharbitis nil ) called 'Shidare-asagao' display agravitropic and weeping growth. It has been shown that this shoot agravitropism may be due to the defective differentiation of endodermal cells that contain statoliths. Roots of the weeping morning glory show normal responsiveness to gravity and the shoots are positively phototropic. Shoots of the morning glory cultivar Violet used as a wild type exhibited distinct circumnutation with circular movements that increase as the plants grow. In weeping morning glory, however, nutation was limited to slight back and forth or side to side movements. To determine whether endodermal cells participate in circumnutation through a function that is independent of their role in gravitropism, the nutational movements of various gravitropic mutants of Arabidopsis thaliana were compared. The inflorescences of wild-type Arabidopsis showed relatively large circular movements. Inflorescences of the pgm-1 mutant, which is defective in starch synthesis, showed reduced nutation. Even more seriously affected were the sgr1-1 / scr-3 and sgr7-1 / shr-2 mutants, which are defective in endodermal cell differentiation, and the auxin-resistant axr2-1 mutant showed no significant nutational movements at all. 1- N -naphthylphthalamic acid (NPA) could inhibit Violet circumnutation, supporting the notion that auxin participates in circumnutation. Thus, the gravitropic response is an essential component in plant shoot circumnutation. Endodermal cells are involved in such circumnutation possibly because of their role in inducing the gravitropic response. 相似文献
948.
Observations on the development of seaweed communities on concretepanels suspended at three different slope angles – 0° (horizontal),45° (inclined) and 90° (vertical) – were carried out atUranouchi Inlet, Tosa Bay, southern Japan. Each panel had two opposite20 × 20 cm areas, which were affixed with six pieces of 6 × 9 cmacrylic plate on which algal communities were allowed to colonize. The panelswere suspended 1 m below the sea surface from a floating platform fora period of 6 weeks. The experiments were repeated nine times fromAugust 1996 to October 1997. Young thalli could already be recognized on the panels after 3–4 weeks. Thetype of algal community developing on a panel varied with the slope angleas well as the period of suspension. These were classified into the threedominant green algal genera: Ulva, Enteromorpha and Cladophora. The cover and biomass of particular species were clearlyinfluenced by the slope of the substratum. 相似文献
949.
Masao Yokoyama Shigeru Amano Atsushi Tsuji Masakiyo Sasahara Tadao Serikawa Nobuo Ihara Masayuki Matsuda Fumitada Hazama Jyoji Handa 《Mammalian genome》2001,12(3):207-211
We analyzed the mode of inheritance of cataract in the Ihara epileptic rat (IER) by crossing experiments, and mapped cataract-related
genes by linkage analysis. Cataract did not develop in the F1 animals, but it developed in both male and female animals of backcross and F2. The occurrence rate of cataract was 48.5% in the backcross progeny and 19.4% in the F2 progeny. Thus, the character was considered to be inherited by the autosomal recessive mode. We found two groups that differed
according to the time of onset among the backcross and F2 progeny: an early-onset group (EOG), in which cataracts developed by about 4 months after birth, and a late-onset group (LOG),
in which cataracts developed 8 months or more after birth. Linkage analysis indicated the presence of one cataract gene each
on Chromosome (Chr) 8 and Chr 15, and the cataract was demonstrated to be governed by more than one gene. The gene on Chr
8 was named Cati1, and that on Chr 15, Cati2. Cati1 was involved in the occurrence of cataract, and the conditions required for cataract to develop were Cati1
i/Cati1
i or Cati1
i/Cati1
w. However, in the cataract rats with Cati1
i/Cati1
w, the allele of Cati2 was always Cati2
i/Cati2
i. Cati2 was involved in the timing of onset of the cataract, and the precondition for early onset was Cati2
i/Cati2
i.
Received: 19 November 1999 / Accepted: 1 November 2000 相似文献
950.
Tomiko Asano Haruo Shinohara † Rika Morishita Hiroshi Ueda Noriko Kawamura Ritsuko Katoh-Semba Masao Kishikawa Kanefusa Kato 《Journal of neurochemistry》2001,79(6):1129-1135
G proteins play important roles in transmembrane signal transduction, and various isoforms of each subunit, alpha, beta and gamma, are highly expressed in the brain. The Ggamma5 subunit is a minor isoform in the adult brain, but we have previously shown it to be highly expressed in the proliferative region of the ventricular zone in the rat embryonic brain. We show here that Ggamma5 is also selectively localized in a proliferative region in the adult rat brain, including the subventricular zone of the lateral ventricle and rostral migratory stream. The Galphai2 subunit colocalized with Ggamma5 in these regions, the two subunits being present in neuronal precursors and ependymal cells but not in proliferating astrocytes. In addition, intense staining of Ggamma5 was seen in axons of the olfactory neurons, which are known to regenerate. These results suggest specific roles for Ggamma5 in precursor cells during neurogenesis so that this isoform might be a useful biological marker. 相似文献