Tachykinin release from rat spinal cord in vitro and in vivo in response to various stimuli

The aim of the present study was to establish an experimental model, previously used in cat, for studying tachykinin release from the rat spinal cord in vivo and to compare the results with those obtained in vitro. Stimulation with pulses of 40 mM potassium or 10 microM capsaicin in the spinal cord superfusion fluid increased the release of substance P (SP)- and neurokinin A (NKA)-like immunoreactivity (LI) both in vivo and in vitro. The amounts of SP-LI and NKA-LI released by potassium in vitro were 1.02 +/- 0.12 and 1.17 +/- 0.22 fmol/mg tissue, respectively. Also the ratio between the amounts released by two consecutive potassium stimulations were similar for SP-LI and NKA-LI. Reversed-phase high performance liquid chromatography of the NKA-LI released in vitro by potassium or capsaicin revealed a major immunoreactive component coeluting with synthetic NKA. Despite the use of highly sensitive radioimmunoassays, basal release of SP-LI and NKA-LI was found only in 9 of 31 in vivo experiments. In these, peripheral electrical stimulation of the sciatic nerves (50 Hz, 50 V and 0.05 ms or 10 Hz, 10 V and 5 ms) induced an increase of the SP-LI and NKA-LI levels in the superfusates. This increase persisted for more than 40 min after a 2 min stimulation. In most experiments, however, no SP-LI or NKA-LI could be detected in the superfusates, neither at basal conditions nor following electrical nerve stimulation. Similarly, no release of SP-LI could be detected in response to various noxious mechanical, thermal or chemical stimuli applied to the skin. The present results demonstrate that the superfused rat spinal cord may be used to study in vivo release of tachykinins in response to intense chemical stimulation of the entire spinal cord. However, the method seems to be less suitable for studies of tachykinin release in response to electrical activation engaging only a few spinal segments or in response to natural noxious stimuli. The results obtained in vitro suggest that SP and NKA are released in equimolar amounts from the spinal cord upon stimulation with potassium.     

Production of DON-related trichothecenes byFusarium graminearum Schw from Krasnodarski krai of the USSR

34Fusarium graminearum Schw isolates produced 4-deoxynivalenol to form significant amounts of 4, 7 — dideoxynivalenol and lesser amounts of 4 — deoxynivalenol monoacetates on grain substratesin vitro. This is the first report on the capability a large group of naturally occurring isolates to produce 4,7-dideoxynivalenol. The average levels of 4,7-dideoxynivalenol on rice, corn, barley, and wheat as a substrate were respectively 26.8, 14.0, 12.8, and 10.5% of the level of 4-deoxynivalenol. 4, 7 — dideoxynivalenol was present in all examined naturally contaminated wheat kernel samples at levels of 1.7 to 7.9% of the level of 4-deoxynivalenol. These findings suggest that more attention should be given to the occurrence of 4,7-dideoxynivalenol in cereals.     

Variation in the ribosomal internal transcribed spacers (ITS1 and ITS2) among eight taxa of the Mimulus guttatus species complex

The internal transcribed spacer region (ITS1 and ITS2) of the 18S-25S nuclear ribosomal DNA sequence and the intervening 5.8S region were sequenced from three individuals in each of eight taxa of the Mimulus guttatus species complex. Three discrete variants, or "types," of ITS sequences were found, among which 30%-40% of sites differed, compared with 1%-2% within types. Dot plots indicate that these types were not related by conspicuous rearrangements or inversions. More than one ITS type was often found in the same taxon, and two of three ITS types span species boundaries, indicating their presence prior to speciation. These ITS sequences showed essentially no positional homology with the nearest sequenced relative, tomato. In contrast, the 5.8S region was relatively unvaried, with 8 of 162 sites varied in the sample among all eight taxa. The phylogeny inferred by the most common ITS sequence type, rooted by the two other ITS types, agreed with isozymes in showing the distinctness of M. nudatus, M. laciniatus, and M. tilingii from the other five taxa.      

中国小菇属十个新记录种

报道了小菇科小菇属真菌10个中国新记录种,香菌组：橙盖小菇Mycena aurantiidisca、黄白小菇Mycena flavoalba、粉黄小菇Mycena floridula;棘刺组：异刺小菇Mycena heteracantha;纤柄组：碱味小菇Mycena amygdalina;脆足组：粉被小菇Mycena zephirus;冬生组：绣线菊小菇Mycena speirea、冬生小菇Mycena hiemalis;小菇组：绒柄小菇Mycena flos-nivium,分别来自吉林等11个省份、自治区。提供了每个物种的形态描述和线条图,以及与相近种的讨论。共计90条自测及下载ITS序列,在采用贝叶斯法和最大似然法构建的小菇属系统发育树中,新记录种均得到分子数据支持。凭证标本存放于吉林农业大学菌物标本馆（HMJAU）。     

川芎嗪对Aβ25-35诱导体外大鼠海马神经元细胞凋亡的影响

本文通过Aβ25-35诱导体外原代培养的SD乳大鼠海马神经元,建立Aβ毒性损伤细胞模型,结合AnnexinV-FITC/PI荧光双染法流式细胞术、MTT比色法、实时荧光定量PCR及Western blot方法检测川芎嗪(tetrameth-ylpyrazine,TMP)对原代培养的海马神经元细胞活性、早期凋亡率和Bax、Bcl-2基因表达的影响。结果显示川芎嗪高、中剂量可明显增强细胞活性,增加神经元细胞的存活率(P<0.01),可显著抑制海马神经元细胞早期凋亡(P<0.01),抑制凋亡蛋白Bax的表达(P<0.01),增强抗凋亡蛋白bcl-2的表达(P<0.01)。川芎嗪可通过调节Bax/Bcl-2平衡抵抗Aβ25-35诱导的海马神经元凋亡,降低Aβ的神经元毒性,对海马神经元损伤有明显的保护作用。     

Modelling expected trout ranges under current and future water temperature regimes in the Eastern Cape,South Africa

Different values have resulted in conflicts between anglers and conservation lobbies in the management of trout in South Africa. Key to the conflict is the demarcation of boundaries to areas in which brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss currently occur, or are likely to establish following stocking for angling. To provide a longer-term perspective on these areas, we developed models to link salmonid biological thermal thresholds to elevation. These, when applied spatially using a digital elevation model with a probability of occurrence model, provided the basis for estimating potentially available thermal habitat for these two cold water species. Here, we acknowledge that other variables (stocking history; river connectivity) also play a role in understanding trout distributions. Using a simple scenario of an increase in mean daily water temperatures of 2 °C, we demonstrated that both brown and rainbow trout are likely to exhibit considerable range reductions in the future. Because it is possible that these range restrictions will result in an increasing desire to introduce trout into areas above their current distribution limits for the maintenance of angling opportunities, conservation managers should prioritise these areas, with management interventions seeking to understand what will help to limit introductions.     

水淹频率变化对鄱阳湖增强型植被指数的影响

水淹状况是湿地植被动态的重要影响因素。该研究基于谷歌地球引擎(GEE)平台, 利用2000-03-01至2020-02-29所有覆盖研究区域的MODIS遥感影像数据, 分析20年间水淹频率(IF)、增强型植被指数(EVI)的时空变化以及湿地植被对IF变化的响应, 得出以下结论: (1) 20年来鄱阳湖水文节律发生了明显改变, 高IF (IF > 75%)水域面积呈现下降趋势, 从2000年1 435.3 km²下降至2019年的510.25 km², 降幅为64.45%; (2)区域平均EVI呈显著上升趋势, 植被扩张主要集中在中部IF下降区域; (3)分析不同总水淹频率区域中平均EVI年际变化, 发现EVI与水淹状况的变化趋势相似, 2009年之后鄱阳湖水域面积萎缩趋势缓解, EVI增长速度出现下降; (4)鄱阳湖湿地植被主要沿水域面积萎缩方向扩张, 基于像元统计20年间IF与EVI的变化趋势, 发现它们在空间分布上高度吻合, 这种空间异质性进一步证实水淹状况起到调节植被动态变化的作用。     

Spinal cord stimulation improves survival in ischemic skin flaps: an experimental study of the possible mediation by calcitonin gene-related peptide

Currently, spinal cord stimulation is used to treat ischemia and ischemic pain, with the best results observed in vasospastic cases. It was earlier demonstrated that spinal cord stimulation may attenuate experimentally induced vasospasm in an island flap in the rat. The present study was designed to investigate whether preemptive spinal cord stimulation could increase long-term flap survival and to explore the neurohumoral mediation of the effect. A total of 56 rats were implanted with chronic spinal cord stimulation systems. Three days later, a groin flap based on the superficial epigastric vessels was harvested, and the single feeding artery was occluded by a detachable microvascular clip. After 12 hours, the clip was removed. Flap survival was evaluated after 7 days. Immediately before flap surgery, two groups of animals received 30 minutes of stimulation using current clinical parameters and with stimulation amplitudes of 70 (n = 10) or 90 percent (n = 8) of that evoking muscular contractions. The outcomes in these groups were compared with those in two control groups (n = 20; n = 10). In one group, an additional calcitonin gene-receptor peptide (CGRP) antagonist was intravenously injected before stimulation (n = 8). In the control groups without stimulation, virtually all flaps necrotized. In treated groups, flap survival was 60 percent at the lower intensity and almost 90 percent at the higher one. The administration of a CGRP antagonist before treatment reduced its efficacy to below 40 percent survival. The differences between the untreated and treated groups were significant. The decrease in survival after CGRP-receptor block was significant in one of two tests. Preemptive spinal cord stimulation increases survival of skin flaps with critical ischemia. The effects are dependent on the stimulation intensity and are possibly mediated by the release of CGRP in the periphery.