Morphological changes in the central vacuole ofBlastocystis hominis during in vitro culture

Summary Morphological changes in the central vacuole during the growth in in vitro culture ofBlastocystis hominis were investigated by light and electron microscopy. Most cells in log phase and an early stationary phase showed a positive staining reaction in the central vacuole with PAS or Sudan black B stain, whereas cells in late stationary phase showed few positive reactions. Electron microscopic observations revealed that 95% ofB. hominis cells in log phase and 50% of cells in early stationary phase, had a substantial accumulation of electron-dense material in the central vacuole. In contrast, only 25% of the organisms in late stationary phase had an electron-dense central vacuole, while more than 50% of cells had an electron-lucent central vacuole. These results indicate thatB. hominis accumulated carbohydrates and lipids in the central vacuole during cell growth and that the organism probably consumed these metabolic substances during stationary growth. Therefore, it is strongly suggested that the central vacuole is an important organelle for storage of metabolic substances, such as carbohydrates and lipids, required for cell growth.Abbreviations PBS phosphate-buffered saline - PAS periodic acid-Schiff     

辽宁三角洲区域生态经济分区及其功能分析

应用主成分分析和系统聚类分析方法,将辽河三角洲划分为３个生态经济区和８个生态经济小区．通过对反映系统功能的３个表现属性的分析,评价了辽河三角洲农业生态经济系统的功能状况．     

中药材分类中的聚类分析

本文应用聚类分析中的系统聚类法与模糊聚类法,对植物药材百合的18个样品进行了聚类．结果不仅两法所得的结论相一致,而且与传统分类的情况相符合．     

Free l-amino acids and d-aspartate content in the nervous system of Cephalopoda. A comparative study

We have determined the content of free l-amino acids and d-aspartate in the nervous tissue of three representative cephalopods: Sepia officinalis, Octopus vulgaris, and Loligo vulgaris, and the optic lobes of adult and embryo Sepia officinalis. Taurine is the most abundant amino acid in the cephalopod nervous tissue. Its content amounts to more than 50% of the total free amino acids. The other most concentrated amino acids are Glu, Ala, Asp, and GABA. High concentrations of d-aspartate were found in the nervous tissue of all cephalopods examined (7–12 μmol/g wet tissue) which represents 50–80% of the total aspartate (d + l), depending on the animal. Among the various regions of the brain of Octopus vulgaris, d-aspartate was found to be evenly distributed in the various regions of the brain. In nerve tissue of Sepia officinalis, there is no significant difference in the pattern of free l-amino acids, in particular of the d-aspartate concentration, between adults and embryos, except for GABA, Gly, His and Thr. This suggests that d-aspartate in nerve tissue of the Cephalopoda is of endogenous origin and not a product of accumulation from exogenous sources. From a comparative study of the content of d-aspartate in the nervous tissue of different animals, we found that protostomia contain a significantly higher amount than deuterostomia. Thus, d-aspartate could be a criterion to distinguish the protostomia phyla from the deuterostomia phyla.     

Mutations in somePolycomb group genes ofDrosophila interfere with regulation of segmentation genes

Mutations in severalPolycomb (Pc) group genes cause maternal-effect or zygotic segmentation defects, suggesting thatPc group genes may regulate the segmentation genes ofDrosophila. We show that individuals doubly heterozygous for mutations inpolyhomeotic and six otherPc group genes show gap, pair rule, and segment polarity segmentation defects. We examined double heterozygous combinations ofPc group and segmentation mutations for enhancement of adult and embryonic segmentation defects.Posterior sex combs andpolyhomeotic interact withKrüppel ² and enhance embryonic phenotypes ofhunchback andknirps, andpolyhomeotic enhanceseven-skipped. Surprisingly, flies carrying duplications ofextra sex combs (esc), that were heterozygous for mutations ofeven-skipped (eve), were extremely subvital. Embryos and surviving adults of this genotype showed strong segmentation defects in even-numbered segments. Antibody studies confirm that expression ofeve is suppressed by duplications ofesc. However,esc duplications have no effect on other gap or pair rule genes tested. To our knowledge, this is only the second triplo-abnormal phenotype associated withPc group genes. Duplications of nine otherPc group genes have no detectable effect oneve. Expression ofengrailed (en) was abnormal in the central nervous systems of mostPc group mutants. These results support a role forPc genes in regulation of some segmentation genes, and suggest thatesc may act differently from otherPc group genes.     

Flight-correlated activity changes in neurons of the lateral accessory lobes in the brain of the locust Schistocerca gregaria

The study investigates activity changes in neurons of the lateral accessory lobes in the brain of the locust Schistocerca gregaria during wind-elicited tethered flight. Neurons with ascending projections from the ventral nerve cord to the lateral accessory lobes showed flight-associated excitations which were modulated in the flight motor rhythm. Descending neurons with ramifications in the lateral accessory lobes were tonically excited corresponding to flight duration. The onset of wind-elicited responses in the descending neurons preceded the onset of flight motor activity by 22–60 milliseconds. Neurons connecting the lateral accessory lobes with the central body, the anterior optic tubercles, or other brain areas showed a variety of responses including activity changes during flight initiation and flight termination. Activity in many of these neurons was less tightly coupled to the flight situation and often returned to background levels before flight was terminated. Most of the recorded neurons responded, in addition, to stationary visual stimuli. The results suggest that the lateral accessory lobes in the locust brain are integrative links between the central body, visual pathways, and the ventral nerve cord. The possible involvement of these brain areas in flight control is discussed.     

罂粟科植物的分类,进化与分布

罂粟科有38属约700种,作者通过对科内各属的研究,根据其主要器官(雌蕊、雄蕊,花被、果和种子)的进化趋势,重新排列科内的分类系统,在3个亚科下,包括8个亚族。在此基础上,讨论各属可能的演化关系,分析它们的分布规律,最后探讨本科的起源。     

一级吸收药物的生物利用度估计的两点法

本文应用系统分析方法,建立了一种一级吸收药物的生物利用度的简便估计的两点法。这种方法,只需测量血管内和血管外给药后的两个相同时点的血药浓度值。不论该药的处置系统是多少室,均能得到较好的结果。这种方法不仅比目前常用的点一点法和点一面法简单,而且结果更精确。     

A comparison of sweating responses during exercise and recovery in terms of sweating rate and body temperature

Based on the hypothesis that the relation between sweating rate and body temperature should be different during exercise and rest after exercise, we compared the sweating response during exercise and recovery at a similar body temperature. Healthy male subjects performed submaximal exercise (Experiment 1) and maximal exercise (Experiment 2) in a room at 27° C and 35% relative humidity. During exercise and recovery of 20 min after exercise, esophageal temperature (Tes), mean skin temperature, mean body temperature ( ), chest sweating rate ( ), and the frequency of sweat expulsion (F _SW) were measured. In both experiments, andF _SW were clearly higher during exercise than recovery at a similar body temperature (Tes, ). was similar during exercise and recovery, or a little less during the former, at a similarF _SW. It is concluded that the sweating rate during exercise is greater than that during recovery at the same body temperature, due to greater central sudomotor activity during exercise. The difference between the two values is thought to be related to non-thermal factors and the rate of change in mean skin temperature.     

Glial cells in adult and developing prothoracic ganglion of the hawk moth Manduca sexta

The glial cells of the prothoracic ganglion of the hawk moth Manduca sexta were studied in histological sections of several postembryonic stages and classified according to cell morphology, size, staining properties, and topographical relationships. In general, each glial cell type was found to be confined to one of the major ganglionic domains and each of these domains (i.e., perineurium, cell body rind, glial cover of the neuropil, and neuropil) was found to comprise specific cell types. Some types of glia were recognized in both larval and later stages, but other types were found exclusively from late pupal stages. It is proposed that the higher morphological diversity expressed by the glia of the pharate adult is attained by differentiation of new cell types during metamorphosis. Before the differentiation of new cell types, extensive cell death and cell proliferation seem to occur within some glial subpopulations.