Failure of short term stimulation to reduce sarcoplasmic reticulum Ca2+-ATPase function in homogenates of rat gastrocnemius

To examine the effect of short term intense activity on sarcoplasmic reticulum (SR) Ca²⁺ sequestering function, the gastrocnemius (G) muscles of 11 anaesthetized male rats (weight, 411±8 g,X±SE) were activated using supramaximal, intermittent stimulation (one train of 0.2 msec impulses per sec of 100 msec at 100 Hz). Homogenates were obtained from stimulated white (WG-S) and red (RG-S) tissues, assayed for Ca²⁺ uptake and maximal Ca²⁺ ATPase activity and compared to contralateral controls (WG-C, RG-C). Calcium uptake (nmoles/mg protein/min) determined using Indo-l and at [Ca²⁺]_f concentrations between 300–400 nM was unaffected (p>0.05) by activity in both WG (6.14+0.43 vs 5.37+0.43) and RG (3.21+0.18 vs 3.07+0.20). Similarly, no effect (p>0.05) of contractile activity was found for maximal Ca²⁺ ATPase activity (mole/mg protein/min) determined spectrophotometrically in RG (0.276+0.03 vs 0.278+0.02). In WG, Ca²⁺ ATPase activity was 15% higher in WG-S compared to WG-C (0.412+0.03 vs 0.385+0.04). Repetitive stimulation resulted in a reduction in tetanic tension of 74% (p<0.05) by 2 min in the G muscle. By the end of the stimulation period, ATP concentration was reduced (p<0.05) by 57% in the WG and by 47% in the RG. These results indicate that the repeated generation of maximal tetanic force, at least for short term periods, need not adversely affectin vitro homogenate determination of Ca²⁺ sequestering function in spite of severe alterations in energy potential and that some other mechanism must be involved to explain the depression in Ca²⁺ uptake and Ca²⁺ ATPase activity previously noted with short term intense exercise.     

短盖巨脂鲤卵巢发育组织学研究

通过对短盖巨脂鲤各个生长时期卵巢组织学研究以及成熟卵超微结构观察,获得短盖巨脂鲤生长发育过程中卵巢发育规律;同时对卵母细胞核仁排出物与核质关系及在卵黄形成中的作用等问题作了初步探讨;并根据卵巢的卵母细胞组成确定了其产卵类型。     

Interaction of Fusarium oxysporum f. sp. ciceri and Meloidogyne javanica on Cicer arietinum

Interaction of Meloidogyne javanica and Fusarium oxysporum f. sp. ciceri was studied on Fusarium wilt-susceptible (JG 62 and K 850) and resistant (JG 74 and Avrodhi) chickpea cultivars. In greenhouse experiments, inoculation of M. javanica juveniles prior to F. oxysporum f. sp. ciceri caused greater wilt incidence in susceptible cultivars and induced vascular discoloration in roots of resistant cultivars. Nematode reproduction was greatest (P = 0.05) at 25 °C. Number of galls and percentage of root area galled increased when the temperature was increased from 15 °C to 25 °C. Wilt incidence was greater at 20 °C than at 25 °C. Chlorosis of leaves and vascular discoloration of plants did not occur at 15 °C. The nematode enhanced the wilt incidence in wilt-susceptible cultivars only at 25 °C. Interaction between the two pathogens on shoot and root weights was significant only at 20 °C, and F. o. ciceri suppressed the nematode density at this temperature. Wilt incidence was greater in clayey (48% clay) than in loamy sand (85% sand) soils. The nematode caused greater plant damage on loamy sand than on clayey soil. Fusarium wilt resistance in Avrodhi and JG 74 was stable in the presence of M. javanica across temperatures and soil types.     

Studying dynamic process of photosensitization by ESR method

By kinetic methods, functional relation of TAN radical, produced in the process of TEMPONE trapping O2, vs. time during photosensitization was established. Accordingly relative rate constants of generating all kinds of active intermediates through types I and II mechanism of photosensitization can be calculated. Using the formula and experimental results, the relative rate constants of generating O2, O2 and PS2 of three kinds of perylenequinone photosensitizer: HA, HB and CP in DMF-H20 and DMSO-H2O system were calculated, and then the structure-activity relationship of perylenequinone photosensitizer and the relation between photosensitivity and solvent was studied.     

籼稻的抗冷性与亲本的关系

四个籼稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）品种幼苗经１℃黑暗或光照２５０ μｍ ｏｌ·ｍ － ２·ｓ－ １处理后,抗冷的“桂山矮选３”比不抗冷的“青华６ 号”幼苗存活率高,其子代是以“桂山矮选３”为母本的比“青华６ 号”为母本的存活率较高。抽穗期剑叶经光照低温处理１２、２４ 和３６ ｈ 后,光合作用是“桂山矮选３”和以“桂山矮选３”为母本的子代比“青华６ 号”和以“青华６ 号”为母本的子代下降较少。呼吸作用是前者比后者在处理１２ ｈ 时有明显升高现象。荧光参数Ｆｖ／Ｆｏ和Ｆｖ／Ｆｍ比值在处理２４ ｈ 时前者比后者下降明显,但在常温下恢复则是前者比后者明显较快。自然低温（寒露风）对叶绿素荧光的影响亦有相似的规律。对水稻后代的抗冷性倾向于母本进行了讨论     

Tyrosine phosphorylation of phosphatase inhibitor 2

Inhibitor 2 is a heat-stable protein that complexes with the catalytic subunit of type-1 protein phosphatase. The reversible phosphorylation of Thr 72 of the inhibitor in this complex has been shown to regulate phosphatase activity. Here we show that inhibitor 2 can also be phosphorylated on tyrosine residues. Inhibitor 2 was ³²P-labeled by the insulin receptor kinase in vitro, in the presence of polylysine. Phosphorylation of inhibitor 2 was accompanied by decreased electrophoretic mobility. Dephosphorylation of inhibitor 2 by tyrosine phosphatase 1B, restored normal electrophoretic mobility. Phosphotyrosine in inhibitor 2 was detected by immunoblotting with antiphosphotyrosine antibodies and phosphoamino acid analysis. In addition, following tryptic digestion, one predominant phosphopeptide was recovered at the anode. The ability of inhibitor 2 to inhibit type-1 phosphatase activity was diminished with increasing phosphorylation up to a stoichiometry of 1 mole phosphate incorporated/mole of inhibitor 2, where inhibitory activity was completely lost. These data demonstrate that inhibitor 2 can be phosphorylated on tyrosine residues by the insulin receptor kinase, resulting in a molecule with decreased ability to inhibit type-1 phosphatase activity.     

Dissection of conjugants and mating type plus and minus cells in selfing clones of the isogamous green alga Closterium ehrenbergii

In the sexual reproduction of the green alga Closterium ehrenbergii, two sexually competent cells that are morphologically indistinguishable from the vegetative cells first come close to each other to form a sexually interacting pair. Each then divides into two gametangial cells. Isogamous conjugation occurs between nonsister gametangial cells of the two resulting pairs. With unusual selfing clones derived from a certain cross of heterothallic strains, we dissected apart a pair of gametangial cells that had already been united together by a delicate transparent tube, into which each gametangial cell was going to develop its conjugation papilla. In spite of such a degree of differentiation, when each was cultured in fresh medium, individual gametangial cells could dedifferentiate into vegetative cells and form subclones. By crossing such subclones with standard stable heterothallic mating-type strains, we show that each selfing clone of this alga actually produces both stable mt ⁺ and stable mt ^- cells, in addition to unstable mt ^- cells with selfing potency, during its mitotic vegetative growth. Although the selfing in C. ehrenbergii studied here differs in certain points from true homothallism, the results of the present study provide insight into how homothallism might have evolved from heterothallism.     

中国粗叶本属（茜草科）的植物地理研究

本文研究了中国产粗叶本属植物３０种４亚种和７变种的地理分布,划分出三个分布区类型,十二个变型和四个亚变型。根据种多度和分布特征,中国粗叶本属植物在分布上表现出与中国的热带雨林、季雨林区,南亚热带常绿阔叶林带和中亚热带常绿阔叶林带相匹配的分布规律,并受几条植物地理界线的作用。通过对地理替代类群和一些特殊分布式样的分析,显示了所谓的“田中线”和一条北起四川峨眉向南经贵州西南部至广西西部的界线对粗叶木种的分布,特别是对中国－喜马拉雅和中国－日本替代分布具有明显的作用。这导致笔者认为“田中线”作为中国－日本分布的西界而另一第线作为中国－喜马拉雅分布的东界。进一步的分析还揭示由云南南部沿缅甸、泰国向南延伸的横断山余脉既充做一条植物南－北迁移的通道又是一条中南半岛西部（印－缅）与东部（印度支那－华南）的植物地理界线。