聚乙二醇处理大豆种子子叶中几种酶活性和可溶性蛋白含量的变化

聚乙二醇处理的大豆种子的异柠檬酸裂解酶、苹果酸脱氢酶、过氧化氢酶、超氧物歧化酶、酸性磷酸酶、碱性磷酸酶的活性明显高于受低温吸胀冷害的种子子叶的活性,相关的酶活性协同地增长,而蛋白质的含量没有明显的变化。这些酶活性的提高可能是渗透调控处理对细胞膜系统修补的结果。     

Dual action of anti-sporozoite antibodies in vitro

With the use of a double staining technique that permits localization of the sporozoite during the process of entering a host cell, we studied the biologic effects of three mAb directed against determinants contained in the circumsporozoite of Plasmodium yoelii. These mAb, which included one IgM and two IgG3, were studied in primary cultures of rodent hepatocytes inoculated with sporozoites of P. yoelii. These results confirm previous reports of the extended action of antibodies on Plasmodium falciparum after entering hepatocytes by producing a strong intrahepatocyte inhibitory effect in addition to the inhibitory effect on sporozoite entry. As with P. falciparum the intracellular effects on P. yoelii liver stages are only observed when the antibodies are present at the time the sporozoite enters the cell. While carrying out experiments on this phenomenon, it was discovered that, at lowered antibody concentrations, an increase in number of maturing liver schizonts occurs, with the increase or enhancement of infection reaching up to 150% of that of controls. It was also observed that there was an inverse relationship between the antibody concentration that was inhibitory and that which enhanced parasite infectivity.     

山东莒南发现的石制品

本文报道的128件人工石制品分别采自山东莒南县的石莲子乡烟敦岭和扁山乡九顶莲花山两个地点。石制品常见类型有边刮器,端刮器和砍斫器等,另有少量的雕刻器和尖状器,内含典型细石器。就石制品的组合及工艺水平而言,其时代可能属于旧石器时代末期。     

Microtubule-dependent retrograde transport of proteins into the ER in the presence of brefeldin A suggests an ER recycling pathway

Characteristics of brefeldin A (BFA)-induced redistribution of Golgi proteins into the endoplasmic reticulum (ER) and its relationship to an ER retrieval pathway were investigated. Retrograde movement of Golgi proteins into the ER occurred via long, tubulovesicular processes extending out of the Golgi along microtubules. Microtubule-disrupting agents (i.e., nocodazole), energy poisons, and reduced temperatures inhibited this pathway. In BFA-treated cells Golgi proteins appeared to cycle between the ER and an intermediate compartment marked by a 53 kd protein. Addition of nocodazole disrupted this dynamic cycle by preferentially inhibiting retrograde movement, causing Golgi proteins to accumulate in the intermediate compartment. In the absence of BFA, such an ER cycling pathway appeared to be followed normally by the 53 kd protein but not by Golgi proteins, as revealed by temperature shift experiments. We propose that BFA induces the interaction of the Golgi with an intermediate "recycling" compartment that utilizes a microtubule-dependent pathway into the ER.     

湖北郧西范家坪早石炭世四射珊瑚

本文描述了贵阳西北郊探矿厂对面山坡上发现的早二叠世晚期茅口组双切尾虫亚科三叶虫的1新属——棘菲利普虫属(Acanthophillipsia),计4新种:Acanthophillipsia guiyangensis, A. abrota, A. abnormis和A.granurosa,丰富了我国二叠纪三叶虫动物群的资料,对研究二叠纪三叶虫的分类、演化和古生物地理分区都具有一定的意义。     

Effect of genotype and medium on wheat (Triticum aestivum L.) anther culture

Four winter wheat (Triticum aestivum L.) and two spring wheat cultivars were evaluated in anther culture on three to four different media for their ability to initiate callus and green plants. Five media were used in the experiment: stored-potato medium with Ficoll 400, fresh-potato medium with Ficoll 400, fresh-potato medium with agar, fresh-potato liquid medium without agar or Ficoll 400, and a one tep 85D12-3 medium. Greatly different frequencies of calli and/or green plants were obtained from different cultivars and media. The callus initiation frequency varied from 2.7% for Arapahoe to 52% for Pavon, both on the stored potato medium with Ficoll 400. The frequency of green plant regeneration ranged from 0% for Arapahoe and Siouxland on the stored-potato medium with Ficoll 400 and 0% for Redland and Arapahoe in the fresh-potato medium with Ficoll 400 to 12% for Chris in the 85D12-3 medium (one-step procedure). Chris and Centurk 78, previously reported as having high levels of response, had significantly higher (P < 0.05) frequencies of green plant regeneration on the 851312-3 medium than the other cultivars. An unexpected observation is that wet MSC^– medium enhanced callus regeneration more than a drier MSC^– medium.     

Cardiac responses elicited by peptides administered to canine intrinsic cardiac neurons.

In order to study the effects of peptides on intrinsic cardiac neurons, substance P, bradykinin, oxytocin, calcitonin gene related peptide, atrial natriuretic peptide and vasoactive intestinal peptide were administered into canine atrial or ventricular ganglionated plexi. When substance P was injected into right atrial or cranial medial ventricular ganglionated plexi heart rate, atrial force and ventricular intramyocardial pressures were augmented. No cardiac changes occurred when similar volumes of saline (i.e., peptide vehicle) were injected into these ganglionated plexi. When bradykinin was injected into atrial or ventricular ganglionated plexi heart rate, atrial force and ventricular force were augmented in approximately 50% and depressor responses were elicited in approximately 50% of these animals. When oxytocin was injected into right atrial ventral ganglionated plexi heart rate and atrial forces were reduced in five of ten dogs studied. No cardiac changes occurred when oxytocin was injected into left atrial or ventricular ganglionated plexi. No responses were elicited when calcitonin gene related peptide, atrial natriuretic peptide or vasoactive intestinal peptide was administered into atrial or ventricular ganglionated plexi. Following acute decentralization of the heart, no significant responses were elicited by repeat administrations of substance P, bradykinin or oxytocin, implying that connectivity with central nervous system neurons was necessary for consistent responses to be elicited. It is concluded that substance P, bradykinin and oxytocin can affect neurons on the heart such that cardiodynamics are modified, these different peptides eliciting different cardiac responses.     

培养大鼠搏动心肌细胞在缺氧和复氧时的电生理观察

应用细胞内微电极技术记录到37个培养大鼠搏动心肌细胞充氮前后和复氧后的电活动参数。结果提示:充氮10min后,最大舒张电位(MDP),最大除极速度(V_(max)),动作电位振幅(APA)和动作电位时程(APD)等参数明显降低;自发节律增快,并出现多种形式的节律失常。83.8％细胞在充氮后30min内停搏,16.2％在50min左右停搏。复氧后,86.5％细胞在5min内复跳,13.5％未能复跳;12.5％复跳细胞在复跳10min内再次停搏。复跳细胞的各项电活动参数在30min内未能恢复到充氮前水平(p<0.05),且呈现不同程度的各类异常电活动。本结果对进一步研究心肌细胞缺氧和复氧损伤有一定意义。     

Ⅱ型限制性核酸内切酶NcrⅠ的研究

 在肉色诺卡氏菌C-212株Nocardia carnea C-212中筛选到一种Ⅱ型限制性核酸内切酶NcrⅠ,经与BglⅡ的λDNA降解物的酶谱比较,以及酶识别特异性和切割位点的检测,证明了NcrⅠ是已知的限制酶BglⅡ的同切限制酶,而且其切割位点也与BglⅡ相同,其为:     

Stationary phase-associated protein expression in Mycobacterium tuberculosis: function of the mycobacterial alpha-crystallin homolog.

The majority of active tuberculosis cases arise as a result of reactivation of latent organisms which are quiescent within the host. The ability of mycobacteria to survive extended periods without active replication is a complex process whose details await elucidation. We used two-dimensional gel electrophoresis to examine both steady-state protein composition and time-dependent protein synthetic profiles in aging cultures of virulent Mycobacterium tuberculosis. At least seven proteins were maximally synthesized 1 to 2 weeks following the end of log-phase growth. One of these proteins accumulated to become a predominant stationary-phase protein. N-terminal amino acid sequencing and immunoreactivity identified this protein as the 16-kDa alpha-crystallin-like small heat shock protein. The gene for this protein was shown to be limited to the slowly growing M. tuberculosis complex of organisms as assessed by Southern blotting. Overexpression of this protein in wild-type M. tuberculosis resulted in a slower decline in viability following the end of log-phase growth. Accumulation of this protein was observed in log-phase cultures following a shift to oxygen-limiting conditions but not by other external stimuli. The protein was purified to homogeneity from overexpressing M. smegmatis in two steps and shown to have a significant ability to suppress the thermal denaturation of alcohol dehydrogenase. Collectively, these results suggest that the mycobacterial alpha-crystallin protein may play a role in enhancing long-term protein stability and therefore long-term survival of M. tuberculosis.