Testosterone regulates smooth muscle contractile pathways in the rat prostate: emphasis on PDE5 signaling

Testosterone (T) plays a permissive role in the development of benign prostatic hyperplasia (BPH), and phosphodiesterase 5 inhibitors (PDE5is) have been found to be effective for BPH and lower urinary tract symptoms (LUTS) in clinical trials. This study investigated the effect of T on smooth muscle (SM) contractile and regulatory signaling pathways, including PDE5 expression and functional activity in prostate in male rats (sham-operated, surgically castrated, and castrated with T supplementation). In vitro organ bath studies, real-time RT-PCR, Western blot analysis, and immunohistochemistry were performed. Castration heavily attenuated contractility, including sensitivity to phenylephrine with SM myosin immunostaining revealing a disrupted SM cell arrangement in the stroma. PDE5 was immunolocalized exclusively in the prostate stroma, and orchiectomy signficantly reduced PDE5 immunopositivity, mRNA, and protein expression, along with nNOS and ROKβ mRNA, whereas it increased eNOS plus α(1a) and α(1b) adrenoreceptor expression in castrated animals. The PDE5i zaprinast significantly increased prostate strip relaxation to the nitric oxide donor sodium nitroprusside (SNP) in control but not castrated rats. But SNP alone was more effective on castrated rats, comparable with sham treated with SNP plus zaprinast. T supplementation prevented or restored all above changes, including SNP and zaprinast in vitro responsiveness. In conclusion, our data show that T positively regulates PDE5 expression and functional activities in prostate, and T ablation not only suppresses prostate size but also reduces prostatic SM contractility, with several potential SM contraction/relaxation pathways implicated. Zaprinast findings strongly suggest a major role for PDE5/cGMP in this signaling cascade. PDE5 inhibition may represent a novel mechanism for treatment of BPH.     

Functional characterization and localization of a gill-specific claudin isoform in Atlantic salmon

Claudins are the major determinants of paracellular epithelial permeability in multicellular organisms. In Atlantic salmon (Salmo salar L.), we previously found that mRNA expression of the abundant gill-specific claudin 30 decreases during seawater (SW) acclimation, suggesting that this claudin is associated with remodeling of the epithelium during salinity change. This study investigated localization, protein expression, and function of claudin 30. Confocal microscopy showed that claudin 30 protein was located at cell-cell interfaces in the gill filament in SW- and fresh water (FW)-acclimated salmon, with the same distribution, overall, as the tight junction protein ZO-1. Claudin 30 was located at the apical tight junction interface and in cell membranes deeper in the epithelia. Colocalization with the α-subunit of the Na(+)-K(+)-ATPase was negligible, suggesting limited association with mitochondria-rich cells. Immunoblotting of gill samples showed lower claudin 30 protein expression in SW than FW fish. Retroviral transduction of claudin 30 into Madin-Darby canine kidney cells resulted in a decreased conductance of 19%. The decreased conductance correlated with a decreased permeability of the cell monolayer to monovalent cations, whereas permeability to chloride was unaffected. Confocal microscopy revealed that claudin 30 was expressed in the lateral membrane, as well as in tight junctions of Madin-Darby canine kidney cells, thereby paralleling the findings in the native gill. This study suggests that claudin 30 functions as a cation barrier between pavement cells in the gill and also has a general role in cell-cell adhesion in deeper layers of the epithelium.     

He—Ne激光对君子兰幼果和胡萝卜根的愈伤组织形成及生长的影响

利用6mv的He—Ne激光器,每天对君子兰幼果、胡萝卜根的外植体辐照5分钟,连续辐照20天,对愈伤组织的形成和生长有一定的促进作用。但同样条件下,辐照10分钟,对君子兰幼果,胡萝卜根的愈伤组织形成和生长都有明显的抑制作用。     

The complete mitochondrial genome of Solen strictus (Bivalvia: Solenidae)

In this paper, we determined the complete mitochondrial genome of Solen strictus (Bivalvia: Solenidae). The whole mitogenome of S. strictus is 16,535?bp in length with a base composition of 21.7% A, 41.0% T, 25.6% C, and 11.7% G and contains 12 protein-coding genes (atp8 is missing), 2 ribosomal RNA genes, 22 transfer RNA genes, and a major non-coding region (MNR). Some peculiar patterns including tandem repeats and microsatellite-like elements are found in the MNR of S. strictus.     

Agrobacterium-mediated production of transgenic rice plants expressing a chimeric α-amylase promoter/β-glucuronidase gene

We have successfully transferred and expressed a reporter gene driven by an -amylase promoter in a japonica type of rice (Oryza sativa L. cv. Tainung 62) using the Agrobacterium-mediated gene transfer system. Immature rice embryos (10–12 days after anthesis) were infected with an Agrobacterium strain carrying a plasmid containing chimeric genes of -glucuronidase (uidA) and neomycin phosphotransferase (nptII). Co-incubation of potato suspension culture (PSC) with the Agrobacterium inoculum significantly improved the transformation efficiency of rice. The uidA and nptII genes, which are under the control of promoters of a rice -amylase gene (Amy8) and Agrobacterium nopaline synthase gene (nos), respectively, were both expressed in G418-resistant calli and transgenic plants. Integration of foreign genes into the genomes of transgenic plants was confirmed by Southern blot analysis. Histochemical localization of GUS activity in one transgenic plant (R0) revealed that the rice -amylase promoter functions in all cell types of the mature leaves, stems, sheaths and roots, but not in the very young leaves. This transgenic plant grew more slowly and produced less seeds than the wild-type plant, but its R1 and R2 progenies grew normally and produced as much seeds as the wild-type plant. Inheritance of foreign genes to the progenies was also confirmed by Southern blot analysis. These data demonstrate successful gene transfer and sexual inheritance of the chimeric genes.     

黄芪改善红细胞变形能力的活性成分研究

膜荚黄芪(Astragalus Membrannaceus(Fisch)Bunge)为豆科紫云英属植物,其根作为传统中药黄芪之正品。本课题通过以改善红细胞变形能力为活性导向筛选,用核孔膜滤筛法,以IF值为指标,对膜荚黄芪的成分进行了系统分离和鉴定。结果表明:黄芪中的黄芪皂甙Ⅱ,Ⅲ,Ⅳ(Astragaloside Ⅱ,Ⅲ,Ⅳ)等皂甙类及芒柄花素(Formononetin),毛蕊异黄酮(Calycosin)等异黄酮类化合物,对孵化红细胞的变形能力有明显的改善作用,这可能是黄芪改善血液流变学指标的重要机理。     

p130/p107 expression distinguishes adipogenic potential in primary myoblasts based on age

Recent investigations have provided significant evidence that many mesodermally derived tissues contain stem cell-like precursors capable of being stimulated to undergo differentiation into a variety of cellular lineages. We have recently reported that primary myoblasts isolated from 23-month-old mice have an increased adipogenic potential when compared to their 8-month-old counterparts. To further characterize the degree of adipocyte differentiation in these myoblasts, we examined early and late markers of adipocyte differentiation. Within the first 24h of adipocyte differentiation, expression of p130 and p107, two members of the retinoblastoma tumor suppressor gene family, are regulated and this event is an important one early in adipogenesis. Consistent with the increased adipogenic potential of the older myoblasts and in contrast to the younger cells, the p130:p107 pattern of expression is very similar to that observed in adipogenesis where there is a transient increase in p107 expression accompanied by a decrease in p130 expression. Interestingly, while these older cells accumulated lipid and expressed genes associated with lipid metabolism, they failed to express adipsin and leptin, two well-established markers of terminal adipocyte differentiation. These results suggest that older myoblasts are capable of initiating and progressing through the adipogenic program to a point where they express genes associated with lipid metabolism, but do not reach a terminally differentiated state. This finding may have important metabolic implications in the aging population.