Phosphorylation and ubiquitination of dynamin-related proteins (AtDRP3A/3B) synergically regulate mitochondrial proliferation during mitosis

The balance between mitochondrial fission and fusion is disrupted during mitosis, but the mechanism governing this phenomenon in plant cells remains enigmatic. Here, we used mitochondrial matrix‐localized Kaede protein (mt‐Kaede) to analyze the dynamics of mitochondrial fission in BY‐2 suspension cells. Analysis of the photoactivatable fluorescence of mt‐Kaede suggested that the fission process is dominant during mitosis. This finding was confirmed by an electron microscopic analysis of the size distribution of mitochondria in BY‐2 suspension cells at various stages. Cellular proteins interacting with Myc‐tagged dynamin‐related protein 3A/3B (AtDRP3A and AtDRP3B) were immunoprecipitated with anti‐Myc antibody‐conjugated beads and subsequently identified by microcapillary liquid chromatography–quadrupole time‐of‐flight mass spectrometry (CapLC Q‐TOF) MS/MS. The identified proteins were broadly associated with cytoskeletal (microtubular), phosphorylation, or ubiquitination functions. Mitotic phosphorylation of AtDRP3A/AtDRP3B and mitochondrial fission at metaphase were inhibited by treatment of the cells with a CdkB/cyclin B inhibitor or a serine/threonine protein kinase inhibitor. The fate of AtDRP3A/3B during the cell cycle was followed by time‐lapse imaging of the fluorescence of Dendra2‐tagged AtDRP3A/3B after green‐to‐red photoconversion; this experiment showed that AtDRP3A/3B is partially degraded during interphase. Additionally, we found that microtubules are involved in mitochondrial fission during mitosis, and that mitochondria movement to daughter cell was limited as early as metaphase. Taken together, these findings suggest that mitotic phosphorylation of AtDRP3A/3B promotes mitochondrial fission during plant cell mitosis, and that AtDRP3A/3B is partially degraded at interphase, providing mechanistic insight into the mitochondrial morphological changes associated with cell‐cycle transitions in BY‐2 suspension cells.     

Patterns of variation in tail ornament size in birds

In recent years several different kinds of sexual selection models have been developed, and tail ornaments in birds have frequently been used as an example of a sexually selected character where the models might apply. However, very little is known about intra- and interpopulation variation in ornament size. We have studied the elongated tail ornaments in four species of whydahs Vidua , the forktailed flycatcher Tyrannus savana and the Asian paradise flycatcher Terpsiphone paradisi. Ornaments were relatively longer in males with the longest tarsi ('heterogony' with positive allometry). Also, tail lengths were remarkably variable within each geographical area, the coefficient of variation (average = 11%) being three times as high as for body size characters. Models, with female preference of ornaments bearing no relation to male viability, usually generate lines of neutral equilibria. Thus, they predict extraordinary variation in ornaments between populations. However, elongated tail ornaments did not show higher geographical variation than the body size characters, suggesting that there is no line of equilibria for these ornaments.     

The acute effect of 30 min of moderate exercise on high density lipoprotein cholesterol in untrained middle-aged men

Fifteen middle-aged, untrained (defined as no regular exercise) men (mean age 49.9 years, range 42-67) cycled on a cycle ergometer at 50 rpm for 30 min at an intensity producing 60% predicted maximum heart rate [(fc,max), where fc,max = 220 - age]. Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglyceride (Tg) concentrations were measured from fasting fingertip capillary blood samples collected at rest, after 15 and 30 min of exercise, and at 15 min post-exercise. The mean HDL-C level increased significantly from the resting level of 0.85 mmol.l-1 to 0.97 mmol.l-1 (P < 0.05) after 15 min of exercise, increased further to 1.08 mmol.l-1 (P < 0.01) after 30 min of exercise and remained elevated at 1.07 mmol.l-1 (P < 0.01) at 15 min post-exercise. These increases represented changes above the mean resting level of 14.1%, 27.1% and 25.9% respectively. The HDL-C/LDL-C ratio increased significantly from a resting ratio of 0.20 to 0.26 after 30 min of exercise (P < 0.01) and to 0.24 at 15 min post-exercise (P < 0.05). The mean Tg level increased significantly from a resting level of 0.88 mmol.l-1 to 1.05 mmol.l-1 after 15 min, and to 1.06 mmol.l-1 after 30 min of exercise (P < 0.05 at each time). The TC/HDL-C ratio decreased significantly (P = 0.05) after 30 min of exercise and at 15 min post-exercise by 18.8% and 14%, respectively. No significant changes were observed in the levels of TC or LDL-C over time.(ABSTRACT TRUNCATED AT 250 WORDS)     

Age-dependent metabolic changes in cultured human fibroblasts

Summary The effects of metabolic poisons on the ATP content of cultured human skin fibroblasts at selected in vitro and in vivo ages were studied. Potassium cyanide, iodacetemide, and Arsenate were used to inhibit ATP restoration by glycolysis and oxidative phosphorylation. Cells treated with these metabolic poisons showed an age-dependent change in their ATP content. The decrease in cellular ATP content after exposure to these drugs was taken as an estimate of ATP turnover. It was found that there was a decrease in the ATP turnover with increasing population doubling level (i.e. in vitro age), and cells cultured from a 68-yr-old donor had a lower ATP turnover than those cultured from a neonatal donor. This decreased ATP turnover correlates with a previous finding of a decreased ability of “older” cells to be stimulated to migrate in culture and suggests that there is a metabolic component to this age-related functional deficiency. This work was supported by National Institutes of Health grants 2, RO1 EY02523 and 1 RO1 1, AGO 1212 awarded to A.L. Muggleton-Harris.     

Detection of TRH extended peptides in rat hypothalamus using an antibody raised to pGluHisProGlyLys

An antibody was raised to the synthetic pentapeptide pGluHisProGlyLys which, in radioimmunoassay (RIA), could detect the pentapeptide at a level of 10 fmole per tube and exhibited <0.5 per cent cross reactivity with a series of related peptides. The RIA was used to demonstrate the presence of C-terminally extended forms of thyrotropin releasing hormone (TRH) in rat hypothalamus. After extraction, the endogenous peptides were resolved by gel exclusion chromatography and TRH-extended peptides were revealed by trypsin digestion to release the pentapeptide. The TRH extended peptides occurred in substantial quantity, approximately 11 pmoles/g, indicating that only partial processing of the gene duplicated prohormone takes place.     

吉林省寄螨亚科三新种(啤螨目:寄螨科)

本文记述寄螨亚科(Parasitinae)三新种。模式标本保存于吉林省地方病第一防治研究所。文内测量单位为微米,括号内为测量平均值。     

电刺激大鼠外侧缰核对延髓甩尾相关细胞的活动和甩尾反射的影响

在浅麻醉大鼠上,在延髓腹内侧结构内观察到三种具有不同放电类型的细胞,即乃尾前放电骤停的撤反应细胞,甩尾前放电骤增的给反应细胞和甩尾无关的中性细胞。电刺激外侧缰核可抑制撤反应细胞的自发放电,加强给反应细胞自发放电,从而易化两类细胞的甩尾相关反应,同时易化伤害刺激引起的甩尾反射。实验结果说明,外侧缰核对节段性防御反射有易化作用,这种易化作用可能是通过延髓内撤反应和反应细胞的协同活动而实现的。     

A mobile cage facilitates periodic social contact and exercise for singly caged adult Vervet monkeys

Abstract: A mobile exercise cage that expands the quantity and improves the quality of the space available to singly caged adult Vervet monkey males is described. It was easily fitted into an existing caging system and the addition of a resident consort female made it possible for the males to mate and have regular social contact.     

Effect of maximal arm exercise on skin blood flux in the paralyzed lower limbs in persons with spinal cord injury

The purpose of the present study was to examine the effect of maximal arm exercise on the skin blood circulation of the paralyzed lower limbs in persons with spinal cord injury (PSCI). Eight male PSCI with complete lesions located between T3 and L1 performed graded maximal arm-cranking exercise (MACE) to exhaustion. The skin blood flux at the thigh (SBFT) and that at the calf (SBFC) were monitored using laser-Doppler flowmeter at rest and for 15 s immediately after the MACE. The subject's mean peak oxygen uptake and peak heart rate was 1.41 ± 0.22 1·min⁻¹ and 171.6 ± 19.2 beats·min⁻¹, respectively. No PSCI showed any increase in either SBFT or SBFC after the MACE, when compared with the values at rest. These results suggest that the blood circulation of the skin in the paralyzed lower limbs in PSCI is unaffected by the MACE.     

猴B病毒相关抗体及B病毒抗体检测的比较研究

本文比较了用ＨＳＶ－１（ＩＥＡ）和Ｂ病毒（ＩＦＡ）的方法检查猴Ｂ病毒相关抗体和Ｂ病毒抗体的结果：ＩＥＡ检查出的Ｂ病毒相关抗体阴性猴,经ＩＦＡ检查,全部为Ｂ病毒抗体阴性。用ＩＦＡ检查了Ｂ病毒相关抗体阴性的恒河猴,在单笼隔离饲养六个月后,有９８．３％的动物Ｂ病毒相关抗体仍为阴性,表明ＩＲＡ的阴性结果有较好的一致性。本文讨论了建立无Ｂ病毒感染猴群的可行性。