HAPLOID PARTHENOGENETIC SPOROPHYTES OF LAMINARIA JAPONICA (PHAEOPHYCEAE)1

Parthenogenetic sporophytes were obtained from three strains of Laminaria japonica Areschoug. These sporophytes grew to maturity in the sea, producine spores that all grew into female gametophytes. These female gametophytes gave rise to another generation of parthenogenetic sporophytes during the next year, so that by the year 1990 parthenogenetic sporophytes had been cultivated for 12, 9, and 7 generations, respectively, for the three strains. When female gametophytes from parthenogenetic sporophytes were combined with normal male gametophytes, normal sporophytes that reproduced and gave rise to both female and male gametophytes were obtained. The parthenogenetic sporophytes were shorter and narrower than the normal sporophytes of the same strain. Chromosome counts on mature sporophytes showed that normal sporophytes (from fertilized eggs) were diploid (2n = approximately 40) and that the spores they produced were haploid (n = approximately 20), while nuclei from both somatic and sporangial cells in parthenogenetic sporophytes were haploid. All gametophytes were haploid. Young sporophytes derived from cultures with both female and male gametophytes were diploid, while young, sporophytes obtained from female gametophytes from parthenogenetic sporophytes had haploid, diploid, or polyploidy chromosome numbers. Polyploidy was associated with abnormal cell shapes. The presence of haploid parthenogenetic sporophytes should be use in breeding kelp strains with useful characteristics, since the sporophyte phenotype is expressed from a haploid genotype which can be more readily selected.     

Dopamine Involved in the Nociceptive Modulation in the Parafascicular Nucleus of Morphine-Dependent Rat

Dopamine regulates pain perception in some areas of the central nervous system. Previously, we have confirmed that dopamine potentiated the electric activities of the evoked discharges of pain-excited neurons (PENs) and inhibited those of pain-inhibited neurons (PINs) in the parafascicular nucleus (Pfn) of normal rats. The mechanism of action of dopamine on pain-related neurons in the Pfn of morphine-dependent rat is still unknown. The present study aimed to determine the effects of dopamine and its receptor antagonist droperidol on the pain-evoked responses of the PEN and PIN in the Pfn of morphine-dependent rats, and to compare the effects between the morphine-dependent rat and the normal rat. The trains of electric impulses applied to the sciatic nerve were used as noxious stimulation. The discharges of PEN or PIN in the Pfn were recorded by using a glass microelectrode. The results showed that intra-Pfn microinjection of dopamine decreased the frequency of noxious stimulation-induced discharges of PEN and increased the frequency of PIN. The intra-Pfn administration of droperidol produced an opposite effect. These results demonstrated that dopamine is involved in nociceptive modulation in the morphine-dependent rat, the responses to noxious stimulation between normal rat and morphine-dependent rat are completely opposite. The effect of dopamine is through the dopamine D₂ receptor of PENs and PINs in Pfn. The results suggest that the dopamine system of the Pfn may become a therapeutic target for analgesia and the treatment of morphine dependence.     

Wistar大鼠心脏自发性病变的病理学观察

目的了解Wistar大鼠心脏自发性病变发病情况,为长期致癌性研究、老年病学研究及毒性病理学提供背景资料。方法采用160只清洁级Wistar大鼠,雌雄各半,常规饲养,分别在9月龄、12月龄、18月龄、24月龄时处死40只大鼠,HE及Masson三色法染色,观察心脏的病理改变。结果 9月龄Wistar大鼠心脏未见明显病理改变;12月龄Wistar大鼠月龄心脏病变的发病率为2.5%（1/40）,表现为少数心肌细胞变性坏死伴少量以单核细胞为主的炎细胞浸润;18月龄大鼠心脏病变的发病率为57.5%（23/40）,表现为轻至中度心肌病,雄性发病率高于雌性。24月龄大鼠100%（40/40）出现不同程度的心肌病,并有2.5%（1/40）发生心内膜下纤维组织增生。Masson染色显示9月龄大鼠心脏血管周围及心脏瓣膜环下有少量胶原纤维,随年龄增长,血管周围及心脏瓣膜环下胶原纤维逐渐增多,并延伸入心肌细胞间。结论随年龄增长,大鼠心脏自发病变比率升高,主要病变为心肌病,偶尔可发生心内膜下纤维组织增生;胶原纤维沉积首先发生于血管周围及心脏瓣膜环下,随年龄增长而增多,可能与大鼠心肌病的的发生密切相关。     

Impaired long-term potentiation and long-term memory deficits in xCT-deficient sut mice

xCT is the functional subunit of the cystine/glutamate antiporter system xc-, which exchanges intracellular glutamate with extracellular cystine. xCT has been reported to play roles in the maintenance of intracellular redox and ambient extracellular glutamate, which may affect neuronal function. To assess a potential role of xCT in the mouse hippocampus, we performed fear conditioning and passive avoidance for long-term memories and examined hippocampal synaptic plasticity in wild-type mice and xCT-null mutants, sut mice. Long-term memory was impaired in sut mice. Normal basal synaptic transmission and short-term presynaptic plasticity at hippocampal Schaffer collateral-CA1 synapses were observed in sut mice. However, LTP (long-term potentiation) was significantly reduced in sut mice compared with their wild-type counterparts. Supplementation of extracellular glutamate did not reverse the reduction in LTP. Taken together, our results suggest that xCT plays a role in the modulation of hippocampal long-term plasticity.     

斜带石斑鱼经葡萄糖灌喂后的代谢反应

糖类的主要生理功能是为动物机体提供能量,而且是比蛋白质和脂肪更为廉价的能源。相对于陆生恒温动物,鱼类尤其是肉食性鱼类对糖的利用能力低下,似乎先天性地具有糖尿病患者的某些生理特征。饲料中过高的糖水平会导致鱼类抗病力下降、生长速度减缓、死亡率增加等症状。鱼类解除葡萄糖负荷的能力有限从而表现     

Autophagy promotes T-cell survival through degradation of proteins of the cell death machinery

Autophagy is implicated in regulating cell death in activated T cells, but the underlying mechanism is unclear. Here, we show that inhibition of autophagy via Beclin 1 gene deletion in T cells leads to rampant apoptosis in these cells upon TCR stimulation. Beclin 1-deficient mice fail to mount autoreactive T-cell responses and are resistant to experimental autoimmune encephalomyelitis. Compared with Th17 cells, Th1 cells are much more susceptible to cell death upon Beclin 1 deletion. Cell death proteins are highly increased in Beclin 1-deficient T cells and inhibition of caspases and genetic deletion of Bim reverse apoptosis. In addition, p62/sequestosome 1 binds to caspase-8 but does not control levels of procaspase-8 or other cell death-related proteins. These results establish a direct role of autophagy in inhibiting the programmed cell death through degradation of apoptosis proteins in activated T cells.     

高速逆流色谱法同时分离制备头花蓼中没食子酸和原儿茶酸

对蓼科蓼属头状蓼组植物头花蓼进行化学成分的研究。本研究建立了HPLC测定中药头花蓼水提喷雾干燥粉末中化学成分含量的方法,然后应用高速逆流色谱法对头花蓼水提喷雾干燥粉末的乙酸乙酯粗提物的化学成分进行了半制备性分离研究,通过对分离方法和溶剂系统的筛选,寻找到最佳的溶剂系统(正己烷∶乙酸乙酯∶甲醇∶水=1∶5∶1∶5),上相为固定相,转速840 r/min,流速2.0 mL/min,进样量756 mg,检测波长272 nm。结果显示,在该条件下经一步分离可同时得到质量为148.5 mg和9.2 mg的两种产物,纯度为99.8%和97.4%,经紫外、红外、质谱及核磁共振等方法进行结构分析,确定分别为没食子酸和原儿茶酸。