武汉东湖桡足类的生态学演变

根据１９６２－１９６３,１９７４－１９７５,１９７９－１９９１年在武汉东湖进行的调查资料,考察了过去三十年内在东湖两个代表性采样站桡足类的种类组成及现存量的变化。结果表明：桡足类种类数由６０年代的１４种减少为９０年代的７种,Ｉ、Ⅱ站在种类组成的差别趋于消失。统计结果表明,东湖桡足类现存量以８０年代初、中期较高。但在水平分布格局上却发生了根本变化,由１９８７年前的Ｉ站现存量高于Ⅱ站,至１９８７年后Ⅱ站高于Ｉ站。本文还就影响东湖桡足类演变的生态因子进行了讨论。     

Discharge patterns of chicken cochlear ganglion neurons following kanamycin-induced hair cell loss and regeneration

Hair cells in the basal, high frequency region (>1100 Hz) of the chicken cochlea were destroyed with kanamycin (400 mg/kg/d × 10 d) and allowed to regenerate. Afterwards, single unit recordings were made from cochlear ganglion neurons at various times post-treatment. During the first few weeks post-treatment, only neurons with low characteristic frequencies (<1100 Hz) responded to sound. Despite the fact that the low frequency region of the cochlea was not destroyed, neurons with low characteristic frequencies had elevated thresholds, abnormally broad U-shaped or W-shaped tuning curves and low spontaneous discharge rates. At 2 days post-treatment, the spontaneous discharge rates of some acoustically unresponsive units fluctuated in a rhythmical manner. As recovery time increased, thresholds decreased, tuning curves narrowed and developed a symmetrical V-shape, spontaneous rate increased and neurons with higher characteristic frequencies began to respond to sound. In addition, the proportion of interspike interval histograms with regularly spaced peaks increased. These improvements progressed along a low-to-high characteristic frequency gradient. By 10–20 weeks post-treatment, the thresholds and tuning curves of neurons with characteristic frequencies below 2000 Hz were within normal limits; however, the spontaneous discharge rates of the neurons were still significantly lower than those from normal animals.Abbreviations KM kanamycin - BrdU bromodeoxyuridine - CF characteristic frequency - CAP compound action potential - ISI interspike interval     

T cell recognition of melanoma antigens in association with HLA-A1 on allogeneic melanoma cells

Previous studies have shown that recognition of melanoma by cytotoxic T lymphocytes may be restricted by HLA-A1, A2 and other HLA antigens. The present study examined the cytotoxic specificity and major histocompatibility complex restriction of cloned cytotoxic T lymphocytes (CTL) isolated from a patient with the HLA phenotype A3,31 who had been immunized with a vaccine prepared from HLA-A1,3 melanoma cells. Cytotoxic assays against HLA-typed allogeneic melanoma cells indicated that cloned CTL from the patient were able to kill allogeneic melanoma cells expressing HLA-A1 but not other HLA-A1-positive cells. Studies on a representative clone indicated that proliferation and cytokine (tumour necrosis factor ) production in response to melanoma cells was also associated with HLA-A1 on melanoma cells. Response to the melanoma cells was associated with interleukin-4 (IL-4) rather than IL-2 production. The antigen recognized in the context of HLA-A1 on allogeneic melanoma cells was detected in cytotoxic assays on cells from 9 of 12 HLA-A1⁺ melanoma cell lines and did not appear to be the product of the MAGE-1 or-3 genes. These findings suggest that T cells can recognize melanoma antigens in the context of alloantigens and that allogeneic vaccines containing immunodominant alloantigens may generate CTL that are ineffective against autologous melanoma. The study does not, however, exclude the possibility that CTL with specificity to the latter may be activated by allogeneic vaccines, and further studies are needed to answer this question.     

Effects of chorda-lingual nerve injury and repair on human taste

Citric acid detection threshold and magnitude response weremeasured on the anterior tongue in 10 patients with unilateralchorda-lingual nerve transections before and after repair. Fungiformtaste buds were analysed by videomicroscopy. Preliminary datasuggests that humans can regenerate fungiform taste buds andrecover some taste sensitivity after repair.     

水稻品种对白背飞虱种群增长的影响

白背飞虱在不同类型水稻品种上的分布、趋性、发育和繁殖力是不同的。它喜欢在杂交稻（汕优6号）上生活和繁殖,取食后成虫寿命最长,取食量、产卵趋性、产卵量、田间虫量均最大,种群增长快;在粳稻上却相反;常规灿稻和糯稻介于二者之间。在同一类型品种中,抗虫品种比感虫品种在上述特性方面差异明显。说明抗虫育种和种植抗虫品种是对该害虫综合治理的一项关键技术。     

祁连山地区植被特征及其分布规律

分析和讨论了祁连山地区主要植被类型及其分布特征。祁连山地区随着青藏高原的强烈隆升表现为整体抬升,植被具有明显的生态地理边缘效应特征和高原地带性规律。该区植被虽然受到四周的较大影响,但各类高寒植被占有绝对优势,表现出与青藏高原植被整体明显的相似性和广泛的一致性。另一方面,本区植被也有其特殊性及与高原面存在一些差异。因此,建议把祁连山地区做为青藏高原植被区的次一级独立单元     

水平回转对水稻幼苗叶细胞的影响

对在模拟微重力装置上回转１４ 天的水稻幼苗叶细胞进行了亚显微形态、电子探针和细胞酶化学研究。发现叶细胞质膜上Ｃａ２＋ －ＡＴＰ酶活性消失,膜内钙总量上升、膜外钙总量下降,细胞骨架变得疏松,细胞壁变薄并凹凸不平。叶绿体的基粒和线粒体的内嵴亦有部分变化。其变化机制,首先是细胞质膜上Ｃａ２＋ －ＡＴＰ酶活性消失,膜上钙泵停止工作,跨膜钙浓度差减小,膜内钙浓度上升,微管、微丝聚合受阻,细胞骨架疏松,分泌泡移动失去导向,从而导致细胞壁变薄等状态     

云南西双版纳兰科十新种

1.豹斑石豆兰 新种 图1:5—6Bulbophyllum colomaculosum Tsi et S. C. Chen, sp. nov.Species nova B. obrieniano Rolfe proxima, a quo differt petalis margine dentatis.Herba epiphytica. pseudobulbi aggregati ovati, ca. 4 cm longi, medio 1.5—1.8 cm lati,     

芦苇耐盐变异植株及其细胞学鉴定

用甲基磺酸乙酯（ＥＭＳ）处理芦苇（Ｐｈｒａｇｍ ｉｔｅｓｃｏｍ ｍ ｕｎｉｓ Ｔｒｉｎ．）胚性愈伤组织。从处理后的愈伤组织诱导获得芦苇耐盐变异植株Ｒ５００２－１２。变异植株能在含有１％ ＮａＣｌ的ＭＳ培养基上生长。细胞学检查变异植株是混倍体,染色体数目变异范围在１００至３３ 之间。分蘖植株具有相似的形态学及染色体变异特性