Moulting hormone,juvenile hormone and the ultrastructure of the fat body of adult Sarcophaga bullata (Diptera)

Summary In the ovoviviparous fly, Sarcophaga bullata, vitellogenesis is cyclic; a process reflected in ultrastructural changes in the fat body cells and oenocytes. At eclosion the larval fat body has not yet completely disappeared. During vitellogenesis the fat body cells are specialized for intensive protein synthesis showing a very extensive RER and numerous invaginations of the plasma membrane. These features disappear when the eggs descend into the oviducts to complete embryogenesis. The predominant feature of the oenocytes is their very prominent SER. The fat body cells of the males are never as specialized for protein synthesis as those of the females. Feeding of ecdysterone to males for 3 or more days induces a rather extensive subcellular apparatus for protein synthesis, i.e., invaginations of the plasma membrane and an extensive RER. Juvenile hormone is completely ineffective in this respect. Both ecdysterone and juvenile hormone have pronounced but different effects on the oenocytes of males.     

The relationship between the nuage and the chromatoid body during spermatogenesis in the Rat

Summary Cytoplasmic structures ultrastructurally similar to the nuage are present in the cytoplasm of all spermatogenic cells in adult rats. The nuage is a discrete organelle which should not be confused with the chromatoid body. In step 7–8 spermatids transient contact is established between the nuage and the chromatoid body. This indicates a very specific recognition of the nuage by the chromatoid body. It is suggested that the nuage and the chromatoid body are separate cell organelles the functions of which are somehow related to each other.     

The control of fruiting body formation in the ascomycete Sordaria macrospora Auersw. by regulation of hyphal development

The morphological effects of biotin and L-arginine on fruiting body formation of the ascomycete Sordaria macrospora are investigated by scanning electron and light microscopy. Biotin is recognized as an elongation factor and arginine as a branching factor in vegetative and reproductive hyphae. In the absence of exogenous biotin, development is blocked after the ascogonium-core hypha stage of protoperithecial morphogenesis, whereas linear growth of the myceliar front is maintained. The addition of exogenous arginine to a biotin deficient culture induces the formation of numerous side branches even in the older mycelium. Fruiting body formation, however, remains blocked at the protoperithecial stage as before, because of the inability of the side branches to elongate. When biotin and arginine are administered simultaneously, a most vigorous branching and growth are induced in the older mycelium, accompanied by a rapid and maximal formation of fruiting bodies. The results are summarized in a model of the exogenous control of hyphal morphogenesis. The model is designed to explain the relationship between fruiting and hyphal density as well as the edge effect on fruiting body formation.     

油菜种子发育早期的油体发生与调控

以甘蓝型油菜（Brassica napus L.）品种‘Westar’和‘Topas’为材料,通过超微结构观察和荧光定量PCR技术对油菜胚胎发育早期油体的发生、油体蛋白及脂肪酸合成转录因子基因的表达情况进行分析。结果显示：油体出现在油菜胚胎发育早期,在授粉9~11 d后（球形胚时期）的胚体和胚柄中均存在直径小于0.5 μm的油体;荧光定量实验结果表明,除BnCLO3的表达量在整个胚胎发育阶段无明显变化外,其他油体蛋白基因Oleosins、Steroleosins和BnCLO1的表达量在心形胚时期就明显增多并持续增长;脂肪酸合成转录因子BnLEC1、BnL1L、BnWRI1和BnFUS3在胚胎发育阶段,基因表达规律均呈先上升再下降的趋势,但达到最高值的时间存在差异,其中BnLEC1最早,BnL1L其次,BnWRI1和BnFUS3较晚。研究结果表明甘蓝型油菜在球形胚时期出现油体,其结构蛋白和转录调控因子基因的表达自心形胚开始明显增多。     

温度对桃蚜、萝卜蚜体重及种群参数的影响

桃蚜Myrus perslcae、萝卜蚜Lipaphis crystml在能正常产仔的整个恒温范围内,成蚜和新产仔蚜体重随温度的变化都符合二次抛物线,但体重最高值出现较低的温度下．即体重变化主要表现为随温度升高而下降的趋势．在组建蚜虫的生命生殖力表时,以新产仔蚜体重对其在各温度下的生殖事进行校正。并未对计算所得的内禀增长能力rm值及其随温度的变化情况产生明显的影响,不仅没有提供新的信息。相反。这一方法使计算所得rm的值含义模糊。故建议不予采用。     

No Effect of Hyperketonemia on Local Cerebral Glucose Utilization in Conscious Rats

Abstract: Local cerebral glucose utilization was measured by the [¹⁴C]2-deoxy- d -glucose method in conscious control and hyperketonemic rats. Hyperketonemia was induced by 3 days of starvation or by infusion of 3- hydroxybutyrate in fed rats. These treatments produced combined blood ketone body concentrations (acetoacetate + 3-hydroxybutyrate) of from 1.2 to 2.4 mM. Neither treatment significantly affected glucose utilization in any of the 15 brain regions studied. These observations indicate that hyperketonemia in resting, conscious rats does not interfere with brain uptake and phosphorylation of glucose.     

Low-angle X-ray scattering analysis of the Thermoplasma acidophilum nucleoprotein subunit

A DNA-protein complex isolated from Thermoplasma acidophilum has been examined using low-angle X-ray scattering measurements. In agreement with the results of electron-microscopic studies a diamter of 5.5 nm is deduced. Finally, a simplified model of the DNA-protein particles is discussed postulating a kinked DNA.     

Body wall of juvenile and adult Gastromermis boophthorae (Nematoda: Mermithidae): Ultrastructure and nutritional role

During the life cycle of the mermithid nematode Gastromermis boophthorae the main components of the body wall, namely the cuticle, hypodermis and somatic musculature, undergo radical changes in structure and relative proportions. In the non-feeding, free-living stages the cuticle is a well-defined, multilayered structure which lies upon a generally thin hypodermis; the somatic musculature has the extensive and highly organised appearance typical of motile nematodes. In parasitic juveniles the body wall has a completely different structure which is adapted for the suggested purpose of nutrient uptake from the host insect's haemocoelomic fluid; the cuticle is characteristically thin and rather diffuse, the underlying hypodermis becomes very extensive and metabolically active, and there is a corresponding reduction in the proportion of somatic musculature. The sub-cuticular surface of the enlarged hypodermis has a microvillous configuration and has associated alkaline phosphatase activity.     

Observations of the pineal region of non-eutherian mammals

Summary A survey has been made of the pineal region of the brain of 11 species of marsupials belonging to 5 families and a species from both families of monotremes.The results show that the pineal body of non-eutherian mammals, although well-defined in all species, has a very varied morphology. Three types of pineal recess occur: (i) a pineal recess in sensu stricto, (ii) an intercommissural pineal recess, and (iii) an infrapineal recess. The existence of nerve fibres which pass through the pineal body and form a spatial link between the habenular and posterior commissures, has been demonstrated in marsupials and monotremes. It is also likely that these animals as well as eutherian mammals possess a nervus conarii. Nerve cells are not a constant feature of the non-eutherian pineal body.The subcommissural organ (SCO) is present in all species. It does not exhibit the same degree of morphological variation as the pineal body. Horizontal sections available for 4 species within 3 families of marsupials show it to be composed of a median portion joined to bilateral protuberances. Large nerve cells occur within the SCO in all marsupial species; they are absent from the monotreme SCO. Tentatively, the relationship of these neurons to the SCO is considered to be merely one of association.The importance of an extended comparative study of this region in non- eutherian mammals in order to add insight into its phylogeny and function is emphasized.