Regulation of tissue inhibitor of metalloproteinases-1 in rat Sertoli cells: induction by germ cell residual bodies, interleukin-1alpha, and second messengers

In the testis, FSH has been shown to induce the expression and secretion of tissue inhibitor of metalloproteinases-1 (TIMP-1) from Sertoli cells in vitro. This study was performed to elucidate further the cellular origin of testicular TIMP-1 and its expression by hormonal and paracrine factors. This is the first report on the expression of testicular TIMP-1 in vivo. TIMP-1 mRNA in whole testis was decreased after hypophysectomy and strongly increased by the injection of FSH-S17 to hypophysectomized rats. Primary cultures of both peritubular and Sertoli cells showed basal expression of TIMP-1 mRNA. In contrast, we were unable to detect TIMP-1 mRNA in Leydig cells, freshly isolated immature germ cells (primary spermatocytes and spermatids), or residual bodies. We further show that treatment of Sertoli cells with 8-(4-chlorophenyl)thio-cAMP (8-CPTcAMP) in combination with 12-O-tetradecanoylphorbol 13-acetate (TPA) or Ca(2+) inducers (calcium ionophore A23187 or thapsigargin) had additive (TPA) and synergistic effects (Ca(2+)) on the level of TIMP-1 mRNA and secreted protein. We also show that both the level of TIMP-1 mRNA and secreted protein from Sertoli cells were strongly increased by residual bodies, as well as by the cytokine interleukin-1alpha. TIMP-1 was not up-regulated by either 8-CPTcAMP or interleukin-1alpha in peritubular cells. In contrast to the regulated secretory fraction of TIMP-1, we also detected constitutively expressed immunoreactive TIMP-1 in the nucleus of Sertoli cells, suggesting a role of nuclear TIMP-1 in these cells. In conclusion, our data show that secretion of TIMP-1 from Sertoli cells is highly regulated by hormonal and local processes in the testis, indicating that TIMP-1 is of physiological importance during both testicular development and spermatogenesis.     

The retinoblastoma gene product regulates progression through the G1 phase of the cell cycle.

The RB gene product is a nuclear phosphoprotein that undergoes cell cycle-dependent changes in its phosphorylation status. To test whether RB regulates cell cycle progression, purified RB proteins, either full-length or a truncated form containing the T antigen-binding region, were injected into cells. Injection of either protein early in G1 inhibits progression into S phase. Co-injection of anti-RB antibodies antagonizes this effect. Injection of RB into cells arrested at G1/S or late in G1 has no effect on BrdU incorporation, suggesting that RB does not inhibit DNA synthesis in S phase. These results indicate that RB regulates cell proliferation by restricting cell cycle progression at a specific point in G1 and establish a biological assay for RB activity. Neither co-injection of RB with a T antigen peptide nor injection into cells expressing T antigen prevents cells from progressing into S phase, which supports the hypothesis that T antigen binding has functional consequences for RB.     

含铬重组液激活部分缺失金属原子簇的钼铁蛋白的研究

棕色固氮菌（Ａｚｏｔｏｂａｃｔｅｒ ｖｉｎｅｌａｎｄｉｉ）固氮酶钼铁蛋白经邻菲口罗啉和Ｏ２ 处理后,变为部分缺失ＦｅＭｏｃｏ 和Ｐ－ｃｌｕｓｔｅｒ的失活蛋白。与由Ｋ２ＣｒＯ４、高柠檬酸铁、Ｎａ２Ｓ和二硫苏糖醇组成的重组液保温后,处理蛋白对乙炔和质子还原的活性都得以显著恢复;然而,它的吸收光谱和圆二色谱虽有明显恢复,但仍与还原钼铁蛋白有所不同。这表明,激活蛋白中也许存在功能与钼铁蛋白相似,而结构则有所差异的含铬（ＣｒＦｅ）蛋白     

microRNA在小鼠乳腺不同发育时期差异表达谱及作用

microRNA是一类大小约22个核苷酸的非编码RNA分子,是一种广泛存在的对基因表达进行微调的分子。microRNA可以通过与靶基因mRNA的特定位点结合,抑制该蛋白的合成或诱导该mRNA的降解,从而参与基因的表达调控。一般来源于染色体的非编码区域,由大约70个核苷酸大小的可形成发夹结构的前体经Dicer酶加工而来。这类小RNA在表达上具有组织和时间的特异性,是调节其他功能基因表达的重要调控分子,在生物的生长发育过程中发挥着重要作用。因此,虽然microRNA的研究仅有很短的历史,但已成为基因表达调控研究的热点领域。以中国昆明小鼠不同发育时期的乳腺组织为实验材料,应用芯片技术及荧光定量PCR技术,分析发育不同时期的乳腺组织microRNA差异表达图谱。本文研究发现microRNA在乳腺不同的发育时期表达图谱不同;与青春期、退化期比较,妊娠期、哺乳期有十余种microRNAs表达上调,20余种microRNAs表达下调;microRNAs在乳腺发育和泌乳周期中发挥重要的作用。     

Biodiesel production from high acid value waste frying oil catalyzed by superacid heteropolyacid

Transesterification of waste cooking oil with high acid value and high water contents using heteropolyacid H3PW12O40 x 6H2O (PW12) as catalyst was investigated. The hexahydrate form of PW(12) was found to be the most promising catalyst which exhibited highest ester yield 87% for transesterification of waste cooking oil and ester yield 97% for esterification of long-chain palmitic acid, respectively. The PW12 acid catalyst shows higher activity under the optimized reaction conditions compared with conventional homogeneous catalyst sulfuric acid, and can easily be separated from the products by distillation of the excess methanol and can be reused more times. The most important feature of this catalyst is that the catalytic activity is not affected by the content of free fatty acids (FFAs) and the content of water in the waste cooking oil and the transesterification can occur at a lower temperature (65 degrees C), a lower methanol oil ratio (70:1) and be finished within a shorter time. The results illustrate that PW12 acid is an excellent water-tolerant and environmentally benign acid catalyst for production of biodiesel from waste cooking oil.     

Recombinant Bacillus thuringiensis strain shows high insecticidal activity against Plutella xylostella and Leptinotarsa decemlineata without affecting nontarget species in the field

Aims: To construct a recombinant Bacillus thuringiensis (Bt) strain with broad insecticidal spectrum and investigate its impact on nontarget organisms in field. Method and Results: The cry-type gene of wild Bt strain UV17 was identified and a novel cry1Ba gene was cloned. The cry3Aa7 gene, which was highly toxic to coleopteran pests, was introduced into UV17, and a recombinant strain designated as UV173A was obtained. Bioassay results showed that UV173A was not only highly toxic against Plutella xylostella (50% lethal concentration [LC₅₀] = 18·03 μg ml^–1), but also against coleopteran Leptinotarsa decernlineata (LC₅₀ = 0·19 mg ml^–1). The recombinant strain was then tested in field trials to monitor its spatial variation of population and to investigate the impact on nontarget invertebrates. Conclusions: A recombinant Bt stain UV173A with broad insecticidal spectrum was obtained, and it did not cause adverse effects on the population of nontarget organisms. Significance and Impact of the Study: The results obtained here indicated that cry1Ba3 gene may be useful for the resistance management of P. xylostella, and the recombinant stain UV173A was potential for field application against some crucifer vegetable pests as well as L. decemlineata.     

Homocysteine inhibits endothelial progenitor cells proliferation via DNMT1-mediated hypomethylation of Cyclin A

Endothelial progenitor cells (EPCs) contribute to neovasculogenesis and reendothelialization of damaged blood vessels to maintain the endothelium. Dysfunction of EPCs is implicated in the pathogenesis of vascular injury induced by homocysteine (Hcy). We aimed to investigate the role of Cyclin A in Hcy-induced EPCs dysfunction and explore its molecular mechanism. In this study, by treatment of EPCs with Hcy, we found that the expression of Cyclin A mRNA and protein were significantly downregulated in a dose-dependent manner. Knockdown of Cyclin A prominently reduced proliferation of EPCs, while over-expression of Cyclin A significantly promoted the cell proliferation, suggesting that Hcy inhibits EPCs proliferation through downregulation of Cyclin A expression. In addition, epigenetic study also demonstrated that Hcy induces DNA hypomethylation of the Cyclin A promoter in EPCs through downregulated expression of DNMT1. Moreover, we found that Hcy treatment of EPCs leads to increased SAM, SAH and MeCP2, while the ratio of SAM/SAH and MBD expression decrease. In summary, our results indicate that Hcy inhibits Cyclin A expression through hypomethylation of Cyclin A and thereby suppress EPCs proliferation. These findings demonstrate a novel mechanism of DNA methylation mediated by DNMT1 in prevention of Hcy associated cardiovascular disease.     

CD31和CD105在卵巢上皮性肿瘤中的表达及其临床病理意义

目的探讨CD31和CD105在卵巢上皮性肿瘤及正常卵巢组织中的表达情况及其与卵巢肿瘤生物学行为之间的关系,并比较同为肿瘤血管内皮标记物的CD31和CDl05在标记微血管方面的差异。方法收集天津市肿瘤医院临床、病理和预后资料完整的恶性卵巢上皮性肿瘤组织标本76例,病例标本采用免疫组化EnVision法检测CD31和CD105所标记的MVD数值,MVD计数参照Weidner方法进行量化分析,实验同时取20例交界性卵巢上皮性肿瘤、10例良性卵巢上皮性肿瘤和10例宫颈癌手术中切除的正常卵巢组织作为对照。结果①CD31蛋白在卵巢上皮性肿瘤的微血管和大血管上均有较强表达,在正常卵巢组织血管中亦有表达,恶性卵巢肿瘤中的MVD-CD31值（5．484-_0．75）显著高于交界性卵巢肿瘤（2．24±0．61）、良性卵巢肿瘤（2．24土0．41）及正常卵巢组织（1．20±0．37）（P〈0．01）;在卵巢癌中,MVD-CD31值仅与有无淋巴结转移及组织学分级之间的差异有统计学意义（P〈O．05）,而与年龄、病理类型、肿瘤大小、腹水、有无远处转移无关（P〉0．05）。②CDl05蛋白在卵巢肿瘤微血管中有表达,在正常卵巢组织中呈微弱表达或无表达,恶性卵巢肿瘤中的MVD-CDl05值（4．07士2．11）显著高于交界性卵巢肿瘤（2．08土0．30）、良性卵巢肿瘤（1．92±1．15）及正常卵巢组织（O．68±0．39）（P〈0．05或P〈0．01）;在卵巢癌中MV口CDl05值与组织学分级、有无腹水、有无远处转移、有无淋巴结转移有关（P〈0．05）,而与年龄、病理类型、肿瘤大小等因素无关（P〉0．05）。③恶性肿瘤组织中的MVD-CD31值显著高于MVD-CDl05值（P〈0．05）。结论在标染卵巢癌方面,CDl05比CD31有明显优越性,CDl05的表达与卵巢癌的生物学行为密切相关,MVD-CDl05值的检测可更准确的确定肿瘤的临床分期、指导治疗及判断预后。     

Production and selected fuel properties of biodiesel from promising non-edible oils: Euphorbia lathyris L., Sapium sebiferum L. and Jatropha curcas L

A comparative study on the composition, biodiesel production and fuel properties of non-edible oils from Euphorbia lathyris L. (EL), Sapium sebiferum L. (SS), and Jatropha curcas L. (JC) was conducted. Under optimal conditions, the FAME content and yield of the three oils were greater than 97.5 wt.% and 84.0%, respectively. The best biodiesel was produced from EL due to its high monounsaturation (82.66 wt.%, Cn: 1), low polyunsaturation (6.49 wt.%, Cn: 2, 3) and appropriate proportion of saturated components (8.78 wt.%, Cn: 0). Namely, EL biodiesel possessed a cetane number of 59.6, an oxidation stability of 10.4 h and a cold filter plug point of -11 °C. However, the cetane number (40.2) and oxidative stability (0.8 h) of dewaxed SS kernel oil (DSSK) biodiesel were low due to the high polyunsaturation (72.79 wt.%). In general, the results suggest that E. lathyris L. is a promising species for biodiesel feedstock.