华溪蟹属三新种的描述（十足目：华溪蟹科）

本文描述了在中国江西、湖南及广东三省发现的华溪蟹属Sinopotmon三个新种:不等叶华溪蟹S.unaequum,sp.nov.,双叶华溪蟹S.bilobatum sp.nov.及南岭华溪蟹S.nanlingense SD.nov.     

影响光合细菌类胡萝卜素形成因素的研究

对已初步确认为球形红假单胞菌属的S—1菌株进行了类胡萝卜素形成因素的研究。通过对光照强度、温度、pH、碳源、氮源、生长因子和无机盐成份等培养条件的探讨,找到了适合类胡萝卜素形成的条件,为开发光合细菌类胡萝卜素提供了依据。     

Reduced susceptibility to HIV-1 infection of ethyl-methanesulfonate-treated CEM subclones correlates with a blockade in their protein kinase C signaling pathway.

We have described the isolation of chemically induced CEM subclones that express CD4 receptors and bind soluble gp120, yet show a markedly reduced susceptibility to infection with HIV-1. Two subclones were found to have an abnormal response to the protein kinase C (PKC) activator PMA. PMA treatment induced CD3 and CD25 (IL-2R) receptors on the parental line and on other ethyl-methanesulfonate-derived subclones, but not on these two mutants. Direct assays of PKC activity were conducted. Total cellular PKC enzymatic activity was found to be normal in these subclones. PMA-induced CD4 down-modulation occurred normally. In addition, activation of c-raf kinase was normal. Since HIV-1 long terminal repeat contains two functional nuclear factor kB (NF-kB) regulatory elements, we studied the ability of PMA to induce NF-kB binding activity by different assays. Chloramphenicol acetyl transferase (CAT) assays using the HIV-1 (-139)long terminal repeat-CAT construct showed no PMA induction of CAT activity in these subclones (unlike the parental line and other subclones). Okadaic acid, an inhibitor of phosphatases 1 and 2A, did not overcome the defect in these subclones. Gel retardation assays, using a 32P-probe containing the HIV-1 NF-kB probe and nuclear extracts from PMA-treated cells, showed significantly reduced induction of nuclear NF-kB binding proteins in these two subclones compared with wild type CEM and a control subclone. Deoxycholate treatment of cytoplasmic extracts from these subclones released much reduced NF-kB binding proteins from their cytoplasmic pools. Thus, reduced levels of PKC-induced nuclear NF-kB activity in two T cell subclones did not affect their normal cell growth, but correlated with a pronounced reduction in their susceptibility to HIV-1 infection.     

Vibrational analysis of crystalline tri-L-alanine

We have found that tri-L-alanine (Ala3) can crystallize in a parallel-chain beta structure in addition to the previously known antiparallel-chain beta structure. Although the chain conformations in each structure are essentially similar, the ir and Raman spectra are distinctively different. We have calculated the normal modes of each structure, and can account in significant detail for these differences. This demonstrates the essential validity of our empirically refined force fields, as well as showing that deeper insights into polypeptide and protein structure can be achieved through the rigorous analyses of normal mode calculations.     

蝉的变音调复合声和发声机制的分析

蛙鸣蝉(Meimuna opalifera (Walk).ab.punctata Kato)的自然鸣声为“ji…guái”的重复单变调复合声.“ji”为主音频约4800Hz的准单音;“guái”的波形和主音频呈明显的演变,优势主频约2100Hz和2800Hz的变音调声.鸟鸣蝉(Meimuna opalifera (Walk)var.formosana Kato)的自然鸣声由重复的“jiū…ruǎ”和“jiū…gū…”合成的双变调复合声.“jiū”为基频和主频分别约625Hz和2100—2300Hz的准单音;“ruǎ”的波形和主音频呈明显的演变,基音和优势主频分别约575—625Hz和1550—1750Hz的变音调声.“gū”为优势主频约625Hz的准单音.变音调复合声不仅与腹部运动有关,而主要取决于发声肌的收缩特性和发声膜肋结构的振动特性.     

稻瘟病菌株的DNA指纹分析及小种鉴别

基于对稻瘟病菌(Pyricularia oryzae)基因文库的分析,我们找到了一套含重复顺序的克隆。其中POR6和POR7被证实具有高度的多态性并随机散布于稻瘟病菌生理小种的致病性时,可以获得可分辨的基因组特异的杂交带型。我们还分析了致病性与8个稻瘟病菌株DNA指纹图谱之间的关系,结果表明各个小种组合间的百分相似率S_xy,值与该小种组合间共同侵染的鉴别品种数目有正相关性。     

Pulmonary vascular reactivity and hemodynamic changes in elastase-induced emphysema in hamsters.

Changes in pulmonary hemodynamics and vascular reactivity in emphysematous hamsters were studied in an isolated lung preparation perfused at constant flow with blood and 3% dextran. Hamsters were treated with intratracheal porcine pancreatic elastase at 70 days of age, and experimental studies were conducted at 1, 3, and 8 mo after treatment. Baseline pulmonary arterial pressure in elastase-treated lungs was increased compared with saline-treated control lungs 1 mo after treatment, but this increase did not progress at 3 and 8 mo. Increases in pulmonary arterial pressure in elastase-treated lungs were temporally correlated with the morphological development of emphysema and right ventricular hypertrophy; both of these were evident at 1 mo after treatment and showed little change thereafter. Pressor responses to hypoxia and angiotensin II were not different between elastase-treated and control lungs at 1 and 3 mo. At 8 mo, however, pressor responses in emphysematous lungs to 0% O2 (but not to angiotensin II) were significantly increased. This was the result of a lack of the normal age-related fall in the hypoxic pressor response. Our results suggest that the right ventricular hypertrophy found in these emphysematous animals results from a chronically increased pulmonary vascular resistance. Furthermore, increases in pulmonary vascular resistance in the early development of emphysema are likely a result of the loss of vascular beds and supporting connective tissue.     

Circ_0008542 in osteoblast exosomes promotes osteoclast-induced bone resorption through m6A methylation

With an increasing aging society, China is the world’s fastest growing markets for oral implants. Compared with traditional oral implants, immediate implants cause marginal bone resorption and increase the failure rate of osseointegration, but the mechanism is still unknown. Therefore, it is important to further study mechanisms of tension stimulus on osteoblasts and osteoclasts at the early stage of osseointegration to promote rapid osseointegration around oral implants. The results showed that exosomes containing circ_0008542 from MC3T3-E1 cells with prolonged tensile stimulation promoted osteoclast differentiation and bone resorption. Circ_0008542 upregulated Tnfrsf11a (RANK) gene expression by acting as a miR-185-5p sponge. Meanwhile, the circ_0008542 1916-1992 bp segment exhibited increased m6A methylation levels. Inhibiting the RNA methyltransferase METTL3 or overexpressing the RNA demethylase ALKBH5 reversed osteoclast differentiation and bone resorption induced by circ_0008542. Injection of circ_0008542 + ALKBH5 into the tail vein of mice reversed the same effects in vivo. Site-directed mutagenesis study demonstrated that 1956 bp on circ_0008542 is the m6A functional site with the abovementioned biological functions. In conclusion, the RNA methylase METTL3 acts on the m6A functional site of 1956 bp in circ_0008542, promoting competitive binding of miRNA-185-5p by circ_0008542, and leading to an increase in the target gene RANK and the initiation of osteoclast bone absorption. In contrast, the RNA demethylase ALKBH5 inhibits the binding of circ_0008542 with miRNA-185-5p to correct the bone resorption process. The potential value of this study provides methods to enhance the resistance of immediate implants through use of exosomes releasing ALKBH5.Subject terms: Epigenetics, Predictive markers     

Analysis of nutrient components of food for Asian elephants in the wild and in captivity

Thirty-seven wild plants as food for Asian elephants in the field in Simao, Yunnan province, China and five cultivated plants as food for captive elephants in the Beijing Zoo were collected and analyzed for their main nutrient components. Protein, fat, fiber, dry material, ash as well as major microelements: calcium, kalium, zincum, sodium in the food were analyzed by standard methodology. No significant differences were found between the wild plants taken in the field and forage provided in captivity. However, the calcium content in the forage is significantly less than the average of those in the wild plants. It is suggested that the increase in calcium intake may contribute to the relief of low plasma calcium diseases of elephants in captivity. Translated from Journal of Beijing Normal University (Natural Science), 2006, 42(2): 184–188 [译自: 北京师范大学学报 (自然科学版)]