Effects of photoperiodicity and light irradiance on phosphate-limited Oscillatoria agardhii in chemostat cultures

Oscillatoria sp. strain 23 is a filamentous, non-heterocystous cyanobacterium that fixes nitrogen aerobically. Although, in this organism nitrogenase is inactivated by oxygen a high tolerance is observed. Up to a pO₂ of 0.15 atm, oxygen does not have any measurable effects on acetylene reduction. Higher concentrations of oxygen inhibited the activity to a relatively high degree. Evidence for two mechanisms of oxygen protection of nitrogenase in this cyanobacterium was obtained. A high rate of synthesis of nitrogenase may allow the organism to maintain a certain amount of active enzyme under aerobic conditions. Secondly, a switch off/on mechanism may reversibly convert the active enzyme into a non-active form which is insensitive to oxygen inactivation after a sudden and short-term exposure to high oxygen concentrations. It is conceived that these mechanisms in addition to a temporal separation of nitrogen fixation from oxygenic photosynthesis sufficiently explain the regulation process of aerobic nitrogen fixation in this organism.Abbreviations DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea - CAP chloramphenicol     

Ecology of gorillas and its relation to female transfer in mountain gorillas

Understanding the principles that underly primate social evolution depends on integrated analysis of data on behavioral ecology, demography, life history tactics, and social organization. In this paper, data on the behavioral ecology of gorillas are reviewed and comparisons made among the three subspecies. Gorillas are selective feeders; and, their patterns of food choice are consistent with models of feeding by large generalist herbivores. They rely heavily on terrestrial herbaceous vegetation, which provides an abundant supply of densely distributed food. Availability of this food varies little in space and time; and, gorilla foraging activity can maintain its productivity. The level of frugivory and the extent of seasonal variation in diet and habitat use vary among and within populations. Low variability in food distribution patterns makes cooperative defense of foraging areas not worthwhile; but, it also means that ecological costs associated with gregariousness are low. However, demographic and life history data on mountain gorillas show that these costs may be sufficient to reduce female reproductive success as group size increases. Advantages to being with high quality males apparently can outweigh these costs. The implications of these data for the evolution of the mountain gorilla social system, and the possible roles of male protection, predation, and female/female competition in this regard, are discussed.     

Long lasting anti-adrenergic effect of 7-oxo-prostacyclin in the heart: a cycloheximide sensitive increase of phosphodiesterase isoform I and IV activities

Evidence is accumulating that 7-oxo-prostacyclin (7-oxo-PGI₂) induces a delayed indirect anti-adrenergic and cytoprotective effect on the myocardium, the mechanism of which is still unclear. To demonstrate that a single application of 7-oxo-PGI₂ (50 g/kg i.m.) 48 h prior to starting experiments attenuates the isoprenaline inducible inotropic response and accumulation of cAMP, isolated hearts of pretreated animals were perfused in the Langendorff mode with and without isoprenaline (1 to 100 nM). The late anti-adrenergic effect of the drug was manifested by a significant attenuation in the elevation of cAMP levels as well as in contractile force development. This effect was not due to changes in cAMP generation as there were identical ₁-adrenoceptor densities and affinities (as calculated from [³H]-CGP binding studies), G_i and G_s protein patterns (as taken from Western blots) as well as adenylyl cyclase activity measurements in the hearts studied. The anti-adrenergic potency of 7-oxo-PGI₂, however, was found to be related to a significant rise in cyclic nucleotide hydrolysis by phosphodiesterase (PDE). Using the fast-performance liquid chromatographic separation for PDE isoforms, a significant increase in the activity of PDE isoforms I and IV (260±28 vs 110±12 pmol cGMP/min x enzyme fraction and 77±11 vs 34±3 pmol cAMP/min x enzyme fraction, respectively) was found in the solubilized fraction of cardiac membranes in comparison to untreated controls; PDE IV activity was also increased in the cytosolic fraction (106±14 vs 65±6 pmol cAMP/min x enzyme fraction). The hypothesis that the delayed anti-adrenergic effect of 7-oxo-PGI₂ is initiated by an induction and accelerated synthesis of PDE I and IV in the heart is underlined by the fact that cycloheximide suppresses completely both the rise in PDE activities and the anti-adrenergic effects studied. It is suggested that an inducible predominance of cAMP degradation over its generation may be of relevance in processes related to heart protection.     

Functional relationship between ammonia and gangliosides in brain

The functional significance of ammonia production in brain under physiological or pathological conditions is not clearly known. NH₄ ⁺ stimulates Na⁺, K⁺ activated ATPase causing stabilization of neuronal membranes of which gangliosides are major structural components. Moreover ammonia is known to inhibit lysosomal enzymes which include enzymes degrading gangliosides. Gangliosides have been shown to stimulate neuritogenesis in neuronal cultures and prevent the damage of the neurons from glutamate toxicity particularly in areas of brain ischemia. Hyperammonemia without any behavioural changes was induced in experimental rats by intraperitoneal administration of either a single dose (0.8 mmol/100 g wt.) or by six hourly doses (0.6 mmol/100 g wt.) of ammonium acetate. An increase in the content of gangliosides along with a rise in the content of GD_1A and GD_1B without any change in -galactosidase and N-acetylhexosaminidase was observed in cerebral cortex, cerebellum, and brain stem, following the administration of single dose of ammonium acetate. Gangliosides, after extraction from the different brain regions, were estimated by the thiobarbituric acid method and expressed in terms of sialic acid. Individual gangliosides were separated and estimated by thin layer chromatography using resorcinol as the staining agent. These results suggest that ammonia production in the neuronal pathways in brain either as a result of repeated stimulation under physiological conditions or as a result of focal ischemia or injury, may likewise cause an increase in the content of gangliosides which may help in neuritic growth (physiological conditions facilitating synaptic plasticity) and may exert a protective effect on the neurons in the ischemic area against glutamate toxicity.Former Professor of Biochemistry, OMC, Hyderabad.     

Anostraca,Notostraca, Laevicaudata and Spinicaudata of Pannonian region and in its Austrian area

The northwestern area of the Pannonian Lowland extends into Austria. The climatic and hydrologic attributes of this biographic region promote the existence of extremely astatic bodies water lacking any fish and hence the occurrence of Anostraca, Notostraca, Laevicaudata and Spinicaudata. Zoogeographical and ecological features as well as the extinction of species due to anthropogenic influence are described.Dedicated to Prof. Dr F. Berger, Lunz, Austria, on the occasion of his 90th birthdayDedicated to Prof. Dr F. Berger, Lunz, Austria, on the occasion of his 90th birthday     

山水林田湖草沙一体化保护和修复工程与景观生态学

我国山水林田湖草沙生命共同体及其保护和修复工程的理论研究和实践正逐渐开展,需要系统的学科理论支撑,景观生态学作为地理学和生态学的交叉科学,能够以其宏观空间理论和技术体系满足这一需求。本文将景观生态学作为山水林田湖草沙一体化保护和修复工程的支撑学科,首先,明确了山水林田湖草沙生命共同体是镶嵌的异质景观、具有景观的所有特征并遵循景观生态学原理;其次,阐述了景观生态建设理论如何应用于山水林田湖草沙一体化保护和修复工程的规划和评价;最后,总结景观生态建设研究的新趋势,提出待解决的理论和实践问题,并论述山水林田湖草沙一体化保护和修复工程如何为解决这些问题提供广阔的研究空间。景观生态学和山水林田湖草沙一体化保护和修复工程实践相结合,将为实现我国乃至全球生态、经济、社会可持续发展提供极为有效的途径。     

Doubling protected land area may be inefficient at preserving the extent of undeveloped land and could cause substantial regional shifts in land use

Projection of land use and land-cover change is highly uncertain yet drives critical estimates of carbon emissions, climate change, and food and bioenergy production. We use new, spatially explicit land availability data in conjunction with a model sensitivity analysis to estimate the effects of additional land protection on land use and land cover. The land availability data include protected land and agricultural suitability and is incorporated into the Moirai land data system for initializing the Global Change Analysis Model. Overall, decreasing land availability is relatively inefficient at preserving undeveloped land while having considerable regional land-use impacts. Current amounts of protected area have little effect on land and crop production estimates, but including the spatial distribution of unsuitable (i.e., unavailable) land dramatically shifts bioenergy production from high northern latitudes to the rest of the world, compared with uniform availability. This highlights the importance of spatial heterogeneity in understanding and managing land change. Approximately doubling the current protected area to emulate a 30% protected area target may avoid land conversion by 2050 of less than half the newly protected extent while reducing bioenergy feedstock land by 10.4% and cropland and grazed pasture by over 3%. Regional bioenergy land may be reduced (increased) by up to 46% (36%), cropland reduced by up to 61%, pasture reduced by up to 100%, and harvested forest reduced by up to 35%. Only a few regions show notable gains in some undeveloped land types of up to 36%. Half of the regions can reach the target using only unsuitable land, which would minimize impacts on agriculture but may not meet conservation goals. Rather than focusing on an area target, a more robust approach may be to carefully select newly protected land to meet well-defined conservation goals while minimizing impacts to agriculture.     

右美托咪定联合芬太尼对心脏瓣膜置换术患者细胞免疫功能的影响及心脑保护作用研究

摘要 目的：观察右美托咪定联合芬太尼对心脏瓣膜置换术患者细胞免疫功能的影响及在心脑保护中的作用。方法：纳入海南医学院第二附属医院2019年4月~2021年6月间接收的体外循环（CPB）下心脏瓣膜置换术患者97例,根据信封抽签法将患者分为对照组（芬太尼,48例）和观察组（右美托咪定联合芬太尼,49例）。对比两组血流动力学指标[平均动脉压（MAP）、心率（HR）]、心肌损伤指标[肌钙蛋白（cTnI）、肌酸激酶同工酶（CK-MB）、心型脂肪酸结合蛋白（HFABP）]、脑损伤指标[神经元特异性烯醇化酶（NSE）、S-100β]、细胞免疫功能、镇痛情况及不良反应发生率。结果：观察组CPB开始后10 min（T2）时间点HR、MAP低于对照组,CPB结束（T3）、术毕（T4）时间点HR、MAP高于对照组（P<0.05）。两组术前（T1）、术后24 h、术后48 h视觉模拟评分法（VAS）评分升高后降低（P<0.05）,观察组术后24 h、术后48 h VAS评分低于对照组（P<0.05）。观察组术后48 h CD4⁺、CD4⁺/CD8⁺高于对照组,CD8⁺低于对照组（P<0.05）。观察组术后48 h cTnI、CK-MB、HFABP低于对照组（P<0.05）。观察组术后48 h NSE、S100B低于对照组（P<0.05）。观察组的不良反应发生率低于对照组（P<0.05）。结论：心脏瓣膜置换术患者选用右美托咪定联合芬太尼麻醉方案,有助于减轻疼痛,稳定血流动力学,减轻免疫抑制,同时还可发挥心脑保护效果,降低不良反应发生率,是一种可靠的麻醉方案。     

丙泊酚联合七氟醚麻醉在先天性心脏病介入手术患儿中的心肌保护作用及对苏醒质量和应激反应的影响

摘要 目的：研究丙泊酚联合七氟醚麻醉在先天性心脏病介入手术患儿中的心肌保护作用及对苏醒质量和应激反应的影响。方法：选择2020年1月~2022年4月期间在苏州大学附属儿童医院接受先天性心脏病介入手术患儿96例,按照双色球法将患儿分为对照组（n=48,接受瑞芬太尼、丙泊酚麻醉）和观察组（n=48,接受丙泊酚、七氟醚麻醉）。对比两组患儿心率、呼吸频率、平均动脉压、苏醒质量、心肌损伤指标、应激反应指标和不良反应发生率。结果：两组置喉罩时（T1）~拔除喉罩（T4）时间点心率、呼吸频率、平均动脉压下降后升高,观察组高于对照组同时间点（P<0.05）。观察组的苏醒时间、拔管时间均短于对照组（P<0.05）。两组术毕、术后24 h肌酸磷酸激酶同工酶（CK-MB）、心肌肌钙蛋白（cTnI）升高后下降,观察组低于对照组同时间点（P<0.05）。两组术毕、术后24 h血糖、皮质醇升高后下降,观察组低于对照组同时间点（P<0.05）。两组不良反应发生率组间对比,差异不显著（P>0.05）。结论：丙泊酚联合七氟醚麻醉应用于先天性心脏病介入手术中,可减轻患儿的应激反应,稳定机体血流动力学波动,同时还可发挥心肌保护作用,提高苏醒质量。     

Protection of plants from frost using hydrophobic particle film and acrylic polymer

Frost damage to potatoes, grapevine and citrus plants was assessed following treatment with either an acrylic polymer (Antistress?) or with a hydrophobic particle film (CM‐96–018). In large freezing tests, the application of the hydrophobic particle film consistently led to less damage whilst the acrylic polymer led to the same amount or more damage when compared to control plants. Detailed examination of the freezing of leaves of all three species using infrared thermal imaging revealed that the hydrophobic particle film delayed the entry of ice from a frozen water droplet containing ice nucleating active bacteria and in some cases for the complete duration of the frost test. In contrast, the acrylic polymer was only able to influence the time of ice nucleation of the leaves of citrus plants. It was concluded that the hydrophobic particle film shows considerable promise as a frost protectant applied to susceptible crops just prior to a freezing event.