Mechanisms of long-term synaptic depression in the hippocampus]

Long-term depression (LTD) was studied in hippocampal slices obtained from neonatal rats at the synapses between CA3 and CA1 pyramidal neurons. The induction of the LTD required pairing of Ca2+ influx into the postsynaptic CA1 neuron through voltage-gated Ca2+ channels with activation of metabotropic glutamate receptors. The expression of this form of LTD is at least partly presynaptic, suggesting the need for a retrograde messenger. We present evidence that arachidonic acid might serve such a function. Thus applications of arachidonic acid simulate LTD whereas blockade of arachiidonic acid release inhibits LTD.     

MSI2通过下调circRNA_001214促进急性髓系白血病细胞HL60生长

Musashi-2（MSI2）是一种RNA结合蛋白质,对维持造血干细胞功能具有重要作用。研究表明,MSI2高表达能促进急性髓系白血病（acute myelocytic leukemia, AML）进展,但其作用机制尚不明确。本研究稳定沉默HL60细胞MSI2后,第1、2、3、4 d对照组的相对细胞生长率分别为1.931 ± 0.027、3.070 ± 0.073、4.017 ± 0.092和4.215 ± 0.246;敲减组分别为1.927 ± 0.035、2.564 ± 0.090、2.825 ± 0.097和3.223 ± 0.182,两组相比具有统计学差异,P<0.001;细胞凋亡明显增加(7.967% ± 0.698% vs 3.400% ± 0.322%., P<0.01);G₀/G₁期细胞比例明显增高（67.430% ± 4.390% vs. 50.360% ± 2.160%, P<0.01）;NUMB蛋白明显上调,LEF1明显下降。环状RNA（circular RNA, circRNA）芯片筛选和荧光定量PCR验证显示,MSI2沉默组circRNA_001214表达水平是对照组3.48倍。这一结果也在NALM6细胞得到证实。进一步用生物信息学分析,显示circRNA_001214最可能与miR-1273a、miR-1273e和miR 5095结合,进而影响参与细胞凋亡相关基因（CYCS、AKT1、BAX、TNFRSF10A、TNFRSF10D）、Wnt信号基因（WNT4、WNT2B、WNT7B、 DKK2、SFRP1、CSNKE1和LEF1）以及参与细胞代谢相关基因（RPE, PGAM4, PGAM1, TAT, CBS、RPE、SUCLG2、PGAM4、PGAM1和 IDNK）。总而言之,MSI2可能通过干扰circRNA_001214生成,减少靶miRNA对凋亡、Wnt信号及细胞代谢相关基因表达的影响,促进细胞生长。     

Changes in sensitivity of clinical strains of bacteria to dioxidine from 1984 to 1988

Dioxidine sensitivity of 7291 strains of aerobic bacteria and 163 strains of anaerobic bacteria was assayed with the disk diffusion method. The sensitivity of the aerobes was studied in the time course from 1984 to 1988. It was shown that during the 5-year period, the sensitivity of gram-positive bacteria to dioxidine gradually decreased. At the same time no increase in resistance of gram-negative organisms to dioxidine was observed. A high dioxidine sensitivity of obligate anaerobes, i.e. Clostridium spp., Bacteroides spp., Fusobacterium spp., anaerobic cocci and others was demonstrated.     

Efficacy of a combination of dioxidine with beta-lactam antibiotics in the prevention and treatment of purulent-inflammatory complications

Schemes for prevention and treatment of purulent inflammatory complications were developed on the basis of in vitro studies on antimicrobial activity of dioxidine and 7 beta-lactam antibiotics such as mezlocillin, carbenicillin, ampicillin, cefotaxime, cefoxitin, cefuroxime and cephalothin under conditions of aero- and anaerobiosis with an account of the isolated microflora, its sensitivity to antibacterial agents and conditions required for vital activity of obligate anaerobes in humans, i.e. decreased partial oxygen pressure, low oxidation-reduction potentials and high tissue concentrations of carbon dioxide. The use of dioxidine in combination with the antimicrobial drugs enabled one to decrease the number of cases with purulent inflammatory complications after large intestine esophagoplasty to 30.4 per cent against 67.5 per cent in the control group of the patients untreated preventively with the antibacterial drugs. The number of cases with similar complications after gastrectomy amounted to 16.1 per cent against 62 per cent in the control. The use of dioxidine+ in combination with ampicillin and cefotaxime in treatment of purulent necrotic affections of the foot in patients with diabetes mellitus enabled one to increase the number of satisfactory outcomes by 32 per cent, to decrease the number of high amputations by 21.9 per cent and to lower the number of deaths more than 2-fold as compared to the results in the control group of the patients subjected to chemotherapy based on sensitivity of the aerobic microflora alone.     

慢性心功能不全大鼠心脏和血淋巴细胞β-肾上腺素受体的改变

在主动脉与肾动脉缩窄造成的慢性心功能不全大鼠,血浆儿茶酚胺浓度增高;心脏β-肾上腺素受体(β-AR)数量增加,其中β_1-AR及其mRNA增加,而β_2-AR及其mRNA不变;左心房异丙基肾上腺素(ISO)浓度-收缩效应曲线右移;而心肌ISO浓度-cAMP蓄积曲线无显著改变;血淋巴细胞β-AR数量显著减少.结果提示心功能不全时心脏β_1-AR数量增多,但其介导的正性变力效应反而降低,在cAMP生成以后的信号转导过程或心肌收缩成分功能存在障碍,而血淋巴细胞β-AR的改变与心脏β-AR的功能改变平行.     

乳源耐甲氧西林金黄色葡萄球菌icaA/D基因缺失株的构建及其生物被膜形成能力与耐药性分析

[背景]耐甲氧西林金黄色葡萄球菌(Methicillin Resistant Staphylococcus aureus,MRSA)是一种具有多重耐药性的人畜共患病原菌,常引起奶牛乳房炎等疾病.形成生物被膜是MRSA重要的耐药机制之一.研究发现ica操纵子调控的胞间多糖黏附素(Polysaccharide Interc...     

我国部分地区自然发酵豆酱中的曲霉菌及其有性型

从我国42个地区的自然发酵酱醅和酱醪样品中分离得到曲霉Aspergillus及其有性型真菌20种,其中优势曲霉菌种类为A.tubingensis、A.flavus、A.niger、A.ochraceus、A.candidus和A.fumigatus.调查研究发现,从酱醅和酱醪样品中分离出黄曲霉的频率较高,表明自然发酵豆酱存在一定的安全隐患.研究中分离获得的曲霉菌株有望用于纯种制曲或特殊风味豆酱的工业化生产.     

绣球菌降血糖作用及活性成分分析

绣球菌是一种珍稀食药用真菌,本文对其醇提取物的降血糖作用及活性成分进行了研究.高脂高糖饲料联合链脲佐菌素造模建立了 Ⅱ型糖尿病小鼠模型,设置空白对照组、模型组、绣球菌提取物高、中、低3个剂量组(300、200和100mg/kg),连续给予相应药物3周,对各组小鼠的体重、血糖、血脂和胰腺进行组织病理学研究.结果显示:与模...     

菜粉蝶幼虫、蛹和成虫的雌雄形态鉴别

利用体视显微镜观察、测量、记录菜粉蝶不同虫态雌雄个体间的形态特征差异。雌雄菜粉蝶幼虫、蛹和成虫均存在显著的雌雄二型特征,3龄之后雄性幼虫的第6腹节有一对肾型黑斑,雌性幼虫无此斑。雄蛹第9腹节有生殖孔和一条短纵裂缝,裂缝两侧有凹凸不平的半圆形瘤状突起;雌蛹腹部第8、9腹节分别有生殖孔和产卵孔,且两孔之间亦有一条纵裂缝。雌蝶前翅背面有一对上下排列的黑圆斑,其腹部末端外生殖器为圆筒型;雄蝶前翅背面一对黑斑相对较小,颜色较浅,尤其下斑为浅灰色,腹部末端具钳状外生殖器。本研究揭示了菜粉蝶幼虫、蛹及成虫不同虫态的雌雄二型差异,比较研究并提出了便于快速鉴别雌雄个体的典型特征和识别方法。