Alterations in synaptosomal neurotransmitter amino acids in “petit-mal” rats at a daytime and a nighttime

The synaptosoma fractions of 6 brain areas-olfactory tubercles (OT), frontal cortex (FC), striatum (Sr), amygdala (A), thalamus (Th), hypothalamus (Hy)-have been analyzed for their neurotransmitter amino acids (AA) content in Wistar rats exhibiting petit-mal epilepsy (PM-E) and in controls (C). The analysis was carried out at 11 p.m. (nighttime corresponding to the acrophase for the hourly number of spike-wave complexes) and at 11 a.m. (daytime). A day versus night rhythmicity is recorded for synaptosomal inhibitory AA in control and in PM-E rats. However, day versus night variations are more frequent and more prominent in C rats than in PM-E rats. Two day versus night variations exist only in PM-E rats: increases of GABA level in Sr and of Asp in Hy. Differences between PME-and C in synaptosomal AA content are more likely to be present during the nighttime. During this period lower AA values for PM-E rats are found for one or several inhibitory AA in OT, Th, and FC. It seems that the differences between PM-E and C concerning the inhibitory AA correlate with the number of spike-wave discharges. Only in one brain area is there a similar difference for PM-E and C during daytime and nighttime: a decreased GABA content for PM-E rats in OT. The decrease is larger in nighttime than in daytime. This difference may serve as a marker for this epileptic disorder. Moreover, it is in OT that the greatest number of PM-E versus C differences in synaptosomal neurotransmitter AA are observed. In view of these and former data, the existence of different alterations in synaptosomal neurotransmitter AA for different types of epilepsy is suggested.Abbreviations used GABA 4-aminobutyrate - Tau taurine - Gly glycine - Asp aspartate - Glu glutamate - Gln glutamine - OT offactory tubereles - FC fronto-parietal cortex - Sr striatum - A amygdala - Th lateral thalamus - Hy lateral hypothalamus - AA neurotransmitter amino acids - I inhibitory - E excitatory - C control rats - PM-E petit-mal rats     

鳗鲡幼鱼耳石日轮的研究

本文报道采自辽东半岛沿岸鳗鲡(Anguilla japonica)的白仔鳗和经人工培育的当年幼鳗耳石日轮生长的观察结果。白仔鳗和幼鳗耳石平均直径均与体全长成直线相关。12尾白仔鳗耳石的平均日轮数146.3,据此推测其产卵期为11—12月。观察证实从咸淡水转人到淡水生活的幼鳗耳石的环纹有过渡带存在。     

Age and growth of tarpon,Megalops atlanticus,larvae in the eastern Gulf of Mexico,with notes on relative abundance and probable spawning areas

Synopsis Leptocephali were collected in June 1981 and July 1989 over the continental shelf and slope of the Florida west coast. Tarpon larvae ranged 5.5–24.4 mm standard length (SL) and were the second most abundant leptocephalus species. Sagittae examined with compound microscopes and scanning electron microscopy had increments that were presumed to be formed daily. Increment counts made using the two microscopic techniques were not significantly different. Estimated ages ranged 2–25 days with a growth rate (± standard error) of 0.92 ± 0.04 mm d^–1 The least squares linear regression equation SL = 2.78 + 0.92 (age in days) best described the relationship between estimated age and length. Adult tarpon appear to undergo a substantial spawning migration from inshore areas frequented during spring and summer to offshore spawning grounds. Spawning occurs during May, June, and July, although the spawning season may be of greater duration.     

A possible discrepancy between the exposed and the whole population depending on range-size and trap-spacing in vole populations

Population Ecology - From a field study for the vole population (Clethrionomys rufocanus) in Hokkaido in the late summer of 1965, it has been proved that the range length may decrease from 25 to 18...     

Search for rhythmicity during hibernation in the European hamster

Temporal patterns of hibernation were studied by continuous monitoring of body temperature by radiotelemetry over 6 months in European hamsters, Cricetus cricetus, at constant temperature and photoperiod. Entrances into hibernation occurred mostly at the end of the night (0000–0800 hours), while arousals were randomly distributed between day and night. This is at variance with a control of bout duration by a clock with a period of 24 h. Consequently, the timing of entrances implies a phase-resetting of the circadian clock on each arousal. Persistence of circadian rhythmicity with a period different from 24 h during deep hibernation was investigated examining whether the durations of torpor bouts were integer multiples of a constant period. A non-parametric version of the classical contingency test of periodicity was developed for this purpose. Periods ranging from 21 to 29 h were tested. Nine animals out of ten showed at least one significant period in this range (P<0.01), either below 24 h (21.8±0.5 h, n=4) or above (27.3±0.5 h, n=7). However, we have found a theoretical model of bout durations for which the contingency test of periodicity sometimes gives false significant results. This indicates that the power of the test is weak. With this reservation our results suggest that a circadian oscillator controls the duration of a bout of hibernation, which would occur after an integer, but variable and possibly temperature-dependent number of cycles.Abbreviations _b a contingency test (see Appendix) - SCN suprachiasmatic nuclei - period - T _b body temperature     

日粮水平对鲇鱼日总代谢,特殊动力作用和活动代谢的影响

在２５℃不同日粮水平（饥饿─４％体重／ｄ）条件下,采用封闭式呼吸仪测定了３１尾鲇鱼（体重７２．９─１３３．３ｇ）的日总代谢率,然后,将鱼限制在呼吸室中的限动笼内测定了其中２０尾鲇鱼的静止日总代谢率,并计算出了鲇鱼的特殊动力作用（ＳＤＡ）和活动代谢率。日总代谢率和活动代谢率都随日粮水平的升高呈“Ｖ”形变化,分别在约１％和２％体重／ｄ的日粮水平时最低,ＳＤＡ的能量支出占摄入能量的２２．１４％。     

Effect of daily photon receipt on the susceptibility of dwarf bean (Phaseolus vulgaris L.) leaves to photoinhibition of photosynthesis

Bean (Phaseolus vulgaris L.) plants were grown at two light periods of 8 and 13 h with a similar photon flux density (PFD) giving a daily photon receipt (DPR) of 17.9 and 38.2 mol · m–2, respectively. Shoot growth and leaf area development were followed at regular intervals and diurnal whole-plant photosynthesis measured. Single mature trifoliate leaves were exposed to photoinhibitory treatments at PFDs of 800 and 1400 mol · m–2 · s–1 and at temperatures of 12 and 20°C. Chlorophyll fluorescence and photon yields were measured at regular intervals throughout each treatment. Plants grown in 13 h had significantly greater leaf areas than those grown in 8 h. There were no differences in maximum rates of photosynthesis, photon yields and only minor but significant differences in F_v/F_m for plants in the two treatments, showing photosynthetic characteristics were dependent on PFD but not DPR. A significant decline in photosynthesis and F_v/F_m occurred over the 13-h but little change in photosynthesis for plants in the 8 h, indicating some feedback inhibition of photosynthesis was occurring. Plants grown in 8 h were consistently more susceptible to photoinhibition of photosynthesis at all treatments than 13-h plants. Nevertheless, photoinhibition was exacerbated by increases in PFD, and by decreases in temperature for leaves from both treatments. However, for plants from the 8-h day, exposing leaves to 12°C and 1400 mol · m–2 · s–1 caused photo-oxidation and severe bleaching but no visible damage on leaves from 13-h-grown plants. Closure of the photosystem II reaction-centre pool was partially correlated with increasing extents of photoinhibition but the relationship was similar for plants from both treatments. There remains no clear explanation for their wide differences in susceptibility to photoinhibition.Abbreviations and Symbols DPR daily photon receipt - F₀ and F_m initial and maximal fluorescence - F_v/F_m fluorescence ratio in dark-treated leaves - F/F_m intrinsic efficiency of PSII during illumination - PFD photon flux density - _i photon yield (incident basis) - _psi quantum yield of PSII electron transport - P_max maximum rate of photosynthesis - q_N non-photochemical quenching coefficient - q_P photochemical quenching coefficient Many thanks to my colleague William Laing who spent a considerable effort in developing the programme to run the photosynthesis apparatus. I am also indebted to one reviewer with whom I corresponded to resolve some issues in the paper. This project was funded by the New Zealand Foundation for Research, Science and Technology.     

Reduction of metabolic rate and thermoregulation during daily torpor

Physiological mechanisms causing reduction of metabolic rate during torpor in heterothermic endotherms are controversial. The original view that metabolic rate is reduced below the basal metabolic rate because the lowered body temperature reduces tissue metabolism has been challenged by a recent hypothesis which claims that metabolic rate during torpor is actively downregulated and is a function of the differential between body temperature and ambient temperature, rather than body temperature per se. In the present study, both the steady-state metabolic rate and body temperature of torpid stripe-faced dunnarts, Sminthopsis macroura (Dasyuridae: Marsupialia), showed two clearly different phases in response to change of air temperature. At air temperatures between 14 and 30°C, metabolic rate and body temperature decreased with air temperature, and metabolic rate showed an exponential relationship with body temperature (r ²=0.74). The Q ₁₀ for metabolic rate was between 2 and 3 over the body temperature range of 16 to 32°C. The difference between body temperature and air temperature over this temperature range did not change significantly, and the metabolic rate was not related to the difference between body temperature and air temperature (P=0.35). However, the apparent conductance decreased with air temperature. At air temperatures below 14°C, metabolic rate increased linearly with the decrease of air temperature (r ²=0.58) and body temperature was maintained above 16°C, largely independent of air temperature. Over this air temperature range, metabolic rate was positively correlated with the difference between body temperature and air temperature (r ²=0.61). Nevertheless, the Q ₁₀ for metabolic rate between normothermic and torpid thermoregulating animals at the same air temperature was also in the range of 2–3. These results suggest that over the air temperature range in which body temperature of S. macroura was not metabolically defended, metabolic rate during daily torpor was largely a function of body temperature. At air temperatures below 14°C, at which the torpid animals showed an increase of metabolic rate to regulate body temperature, the negative relationship between metabolic rate and air temperature was a function of the differential between body temperature and air temperature as during normothermia. However, even in thermoregulating animals, the reduction of metabolic rate from normothermia to torpor at a given air temperature can also be explained by temperature effects.Abbreviations BM body mass - BMR basal metabolic rate - C apparent conductance - MR metabolic rate - RMR resting metabolic rate - RQ respiratory quotient - T _a air temperature - T _b body temperature - T _lc lower critical temperature - T _tc critical air temperature during torpor - TMR metabolic rate during torpor - TNZ thermoneutral zone - T difference between body temperature and air temperature - VO₂ rate of oxygen consumption     

Annual changes in brain concentration of arginine vasotocin and isotocin correspond with phases of reproductive cycle in round goby,Neogobius melanostomus

Reproductive cycle of seasonally breeding fish is synchronized with changes of photoperiod and temperature in environment. We hypothesize that arginine vasotocin (AVT) and isotocin (IT) are involved in timing and synchronization of seasonal reproductive activity in the round goby (Neogobius melanostomus). To verify this hypothesis, we examined the annual profiles of brain AVT and IT in round goby males and females in relation to their reproductive cycle. Wild round gobies were exposed to annual environmental changes in their natural habitats from where they were sampled monthly over a year. AVT and IT were measured using HPLC with fluorescence detection preceded by solid-phase extraction. This study shows seasonal variations in brain AVT and IT levels. Profiles of changes were similar in males and females: the peak of AVT was observed before spawning in March-April, whereas that of IT during spawning in May–June. Furthermore, the lowest AVT level was noted out of breeding season from November to January, while the level of IT decreased immediately at the end of the spawning. The results show that high AVT levels correlate with pre-spawning period whereas the highest IT levels correspond to spawning. A significant decline in AVT and IT in non-spawning season coincided with the quiescent phase of gametogenesis in both sexes.     

群体大小和觅食环境变化对东黑冠长臂猿日移动距离的影响

日移动距离是反映动物觅食努力的重要指标之一,相关研究有助于了解动物对生境的适应策略,对濒危物种的保护至关重要。东黑冠长臂猿（Nomascus nasutus）是一种极度濒危的树栖小型类人猿,主要生活在一夫二妻制的群体中,平均群体大小6.3只,目前对于该物种的日移动距离仍然缺乏足够的科学研究。我们以广西邦亮长臂猿国家级自然保护区内两群东黑冠长臂猿群作为研究对象,在2008年4月至2009年12月、2016年10月至2017年8月两个时期对其进行了157个全天跟踪,使用5 min间隔的瞬时扫描法记录长臂猿的取食行为和食物类型,每30 min记录长臂猿的位点,并使用轨迹法测算出日移动距离。结果发现东黑冠长臂猿在两个观察时期的不同食物类型取食比例有显著差异,全年的平均日移动距离为1 373 m （354~2 837 m）,相比于低纬度地区营一夫一妻制（平均群体大小3.8只）生活的长臂猿类群没有明显增加。这一结果说明,虽然群体更大,但是东黑冠长臂猿并没有增加每天的觅食努力,不符合生态限制模型的预测。更大的食物斑块、更小的种间竞争和低群体密度可能是支持东黑冠长臂猿无需付出更多的觅食努力来维持更大群体的原因。另外,我们还发现东黑冠长臂猿在人类干扰强度低的研究时期果实类取食比例提高,日移动距离更长,且在果实丰富的雨季日移动距离显著高于果实匮乏的旱季,表明它们可能采取能量保守的策略来应对高质量食物匮乏的环境。总的来说,本研究在更大数据量的基础上更加准确和详细地描述了东黑冠长臂猿的日移动距离,并以此探究长臂猿对高质量食物匮乏环境的响应,为该极度濒危物种的保护提供更多的科学信息。