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81.
Distribution of the molossinus allele of Sry, the testis-determining gene, in wild mice 总被引:3,自引:0,他引:3
Nagamine CM; Shiroishi T; Miyashita N; Tsuchiya K; Ikeda H; Takao N; Wu XL; Jin ML; Wang FS; Kryukov AP 《Molecular biology and evolution》1994,11(6):864-874
When the Y chromosome of the laboratory inbred mouse strain C57BL/6 (B6) is
replaced by the Y of certain strains of Mus musculus domesticus, testis
determination fails and all XY fetuses develop either as hermaphrodites or
XY females (XY sex reversal). This suggests the presence of at least two
alleles of Sry, the male-determining gene on the Y:M. m. domesticus and B6.
The B6 Y chromosome is derived from the Japanese house mouse, M. m.
molossinus and therefore carries a molossinus Sry allele. As a first step
to determine how the molossinus Sry allele evolved, its distribution
pattern was determined in wild mice. The cumulative data of 96 M. musculus
samples obtained from 58 geographical locations in Europe, North Africa,
and Asia show the molossinus Sry allele is restricted to Japan and the
neighboring Asian mainland and confirm that Japanese M. m. molossinus mice
were derived in part from a race of M. m. musculus from Korea or Manchuria.
Sry polymorphisms, as illustrated by the molossinus Sry allele, can serve
as molecular markers for studies on the evolution of wild M. musculus
populations and can help determine the role sex determination plays in
speciation.
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82.
Papakonstantinou E; Karakiulakis G; Eickelberg O; Perruchoud AP; Block LH; Roth M 《Glycobiology》1998,8(8):821-830
The formation of atherosclerotic lesions is characterized by invasion of
vascular smooth muscle cells (VSMC) into the tunica intima of the arterial
wall and subsequently by increased proliferation of VSMC, a process
apparently restricted to the intimal layer of blood vessels. Both events
are preceded by the pathological overexpression of several growth factors,
such as platelet-derived growth factor (PDGF) which is a potent mitogen for
VSMC and can induce their chemotaxis. PDGF is generally not expressed in
the normal artery but it is upregulated in atherosclerotic lesions. We have
previously shown that PDGF-BB specifically stimulates proliferating VSMC to
secrete a 340 kDa hyaluronic acid (HA-340). Here, we present evidence
regarding the biological functions of this glycan. We observed that HA-340
inhibited the PDGF-induced proliferation of human VSMC in a dose-dependent
manner and enhanced the PDGF-dependent invasion of VSMC through a basement
membrane barrier. These effects were abolished following treatment of
HA-340 with hyaluronidase. The effect of HA-340 on the PDGF-dependent
invasion of VSMC coincided with increased secretion of the 72-kDa type IV
collagenase by VSMC and was completely blocked by GM6001, a hydroxamic acid
inhibitor of matrix metalloproteinases. HA-340 did not exert any
chemotactic potency, nor did it affect chemotaxis of VSMC along a PDGF
gradient. In human atheromatic aortas, we found that HA- 340 is expressed
with a negative concentration gradient from the tunica media to the tunica
intima and the atheromatic plaque. Our findings suggest that HA-340 may be
linked to the pathogenesis of atherosclerosis, by modulating VSMC
proliferation and invasion.
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83.
Monoamine oxidase‐A is a novel driver of stress‐induced premature senescence through inhibition of parkin‐mediated mitophagy 下载免费PDF全文
Nicola Manzella Yohan Santin Damien Maggiorani Hélène Martini Victorine Douin‐Echinard Joao F. Passos Frank Lezoualc'h Claudia Binda Angelo Parini Jeanne Mialet‐Perez 《Aging cell》2018,17(5)
Cellular senescence, the irreversible cell cycle arrest observed in somatic cells, is an important driver of age‐associated diseases. Mitochondria have been implicated in the process of senescence, primarily because they are both sources and targets of reactive oxygen species (ROS). In the heart, oxidative stress contributes to pathological cardiac ageing, but the mechanisms underlying ROS production are still not completely understood. The mitochondrial enzyme monoamine oxidase‐A (MAO‐A) is a relevant source of ROS in the heart through the formation of H2O2 derived from the degradation of its main substrates, norepinephrine (NE) and serotonin. However, the potential link between MAO‐A and senescence has not been previously investigated. Using cardiomyoblasts and primary cardiomyocytes, we demonstrate that chronic MAO‐A activation mediated by synthetic (tyramine) and physiological (NE) substrates induces ROS‐dependent DNA damage response, activation of cyclin‐dependent kinase inhibitors p21cip, p16ink4a, and p15ink4b and typical features of senescence such as cell flattening and SA‐β‐gal activity. Moreover, we observe that ROS produced by MAO‐A lead to the accumulation of p53 in the cytosol where it inhibits parkin, an important regulator of mitophagy, resulting in mitochondrial dysfunction. Additionally, we show that the mTOR kinase contributes to mitophagy dysfunction by enhancing p53 cytoplasmic accumulation. Importantly, restoration of mitophagy, either by overexpression of parkin or inhibition of mTOR, prevents mitochondrial dysfunction and induction of senescence. Altogether, our data demonstrate a novel link between MAO‐A and senescence in cardiomyocytes and provides mechanistic insights into the potential role of MAO‐dependent oxidative stress in age‐related pathologies. 相似文献
84.
Annexin A1 Is a Physiological Modulator of Neutrophil Maturation and Recirculation Acting on the CXCR4/CXCL12 Pathway 下载免费PDF全文
85.
86.
Ultrastructural and morphometric characterization of buffalo (Bubalus bubalis) ovarian preantral follicles 总被引:1,自引:0,他引:1
The main objective of the present study was to characterize buffalo preantral ovarian follicles. Parts of ovarian cortex, collected from postpubertal buffalo females that were having estrous cycles at regular intervals, were selected under stereomicroscopy and processed for optic and transmission electron microscopy. Primordial follicles were characterized as an oocyte encircled by one layer of flattened cells. The buffalo primordial follicle has a mean diameter of 35 microm and the oocyte diameter is 24.9 microm. The oocyte nucleus is relatively large and eccentric; and in the cytoplasm a large amount of mitochondria, vesicles and endoplasmic reticulum cistern, mainly of the smooth type is observed. The primordial follicles cells are rich in plasma membrane invaginations, which are observed within the cell and between the cell and the oocyte. The primary follicles (mean diameter of 41.8 microm) consist of an oocyte, with a medium diameter of 26.9 microm, surrounded by one layer of cubical granulosa cells. At this follicular stage, the beginning of zona pellucida deposition can also be seen in areas between the oocyte and follicular cells. The secondary follicles, which are surrounded by more than one layer of cubical cells, have a diameter of 53.3 microm, and the oocyte has a mean diameter of 29.4 microm. The ultrastructural analysis showed a large amount of coalescent vesicles, more evident in the oocyte periphery. The zona pellucida (ZP) is thicker at this stage and contains a large quantity of glycoproteins. In general, the ultrastructure of buffalo preantral follicles was similar to that of other mammalian species, but some differences were observed, which indicate species specific characteristics. The main differences observed were cytoplasmic vesicles quantity, mitochondria shape and inner content, ZP deposition and granulosa cell-oocyte junctions. In conclusion, the morphological differences described in this paper, could be responsible for some functional differences observed in Bubalus bubalis in vitro embryo production and follicular dynamics, when compared with Bos taurus or Bos indicus species. 相似文献
87.
Domestication of a housekeeping transglycosylase for assembly of a Type VI secretion system 下载免费PDF全文
The type VI secretion system (T6SS) is an anti‐bacterial weapon comprising a contractile tail anchored to the cell envelope by a membrane complex. The TssJ, TssL, and TssM proteins assemble a 1.7‐MDa channel complex that spans the cell envelope, including the peptidoglycan layer. The electron microscopy structure of the TssJLM complex revealed that it has a diameter of ~18 nm in the periplasm, which is larger than the size of peptidoglycan pores (~2 nm), hence questioning how the T6SS membrane complex crosses the peptidoglycan layer. Here, we report that the MltE housekeeping lytic transglycosylase (LTG) is required for T6SS assembly in enteroaggregative Escherichia coli. Protein–protein interaction studies further demonstrated that MltE is recruited to the periplasmic domain of TssM. In addition, we show that TssM significantly stimulates MltE activity in vitro and that MltE is required for the late stages of T6SS membrane complex assembly. Collectively, our data provide the first example of domestication and activation of a LTG encoded within the core genome for the assembly of a secretion system. 相似文献
88.
89.
Viegas Eduardo Santin Altair Bachtold Juliana Segalin Darlan Stihler Maicon Marcon Arlindo Maziero Carlos 《Cluster computing》2021,24(3):1659-1674
Cluster Computing - Enforcing Service Level Agreements (SLA) on service provisioning is a challenge in cloud computing environments. This paper proposes an architecture for multiparty (provider and... 相似文献
90.