Myoanatomy of <Emphasis Type=Italic>Barentsia discreta</Emphasis> (Busk, 1886) (Kamptozoa: Coloniales)

The anatomy of the muscular system of Barentsia discreta (Kamptozoa) was studied by confocal laser scanning and transmission electron microscopy. The calyx musculature, muscles associated with the digestive tract, atrial ring muscles, and tentacle muscles are described. The structure of the muscular bulbus located in the upper part of the stalk and the muscle base of the stalk were examined. The middle part of the stalk and the stolon lack musculature. The structure of the star-cell complex lying at the boundary of the stalk and calyx was examined in detail. Emschermann’s (1969) opinion was confirmed that the star-cell complex performs the function of a heart, providing the transport of substances from the calyx to the stalk and stolon. The general plan of the muscle arrangement is similar in all Kamptozoa; it consists of central muscles of the calyx, atrial ring muscles, tentacle muscles, and muscles associated with the digestive tract. Oral, lateral, and aboral muscles extending from the stalk into the calyx, which were described for solitary forms, are lacking in the calyx of colonial B. discreta. The calyx of B. discreta is separated from the stalk by a septum, through which muscles do not penetrate from the stalk.     

Neurospora discreta,a new heterothallic species defined by its crossing behavior

The species is described and namedNeurospora discreta sp. nov. because of its stringent reproductive isolation. Isolates collected from burned vegetation at a single site near Kirbyville, Texas, include both mating types (Aanda). Experimental criteria based on cross-fertility were used for assigning species status. Crosses between isolates of opposite mating type are highly fertile, producing abundant eightspored asci. In contrast, when the Kirbyville strains are crossed to sexually compatible speciestester strains representingN. crassa, N. intermedia, N. sitophila, andN. tetrasperma, perithecia are rudimentary and no ascospores are produced. The haploid chromosome number is 7. Chromosomes at pachytene resemble those of otherNeurospora species. Biotin is required. Linear growth is slower than for other heterothallic species. When A and a strains from Kirbyville grow toward one another and intersect on crossing medium, there is no barrage. A single homogeneous band of perithecia is formed where they meet, indicating that opposite mating types are vegetatively compatible. The Kirbyville population differs from other heterothallicNeurospora species in ascospore morphology and vegetative traits. Ascospores from Kirbyville parents are larger, and the ribs between confluent parallel grooves are ornamented with dot-like pits. Vegetative cultures from Kirbyville are yellowish rather than orange, and large empty barren protoperithecia or false perithecia are produced abundantly in unfertilized haploid cultures. Isolates from two otherN. discreta populations resemble otherNeurospora species more closely with respect to these morphological traits but are clearly conspecific with the Kirbyville strains on the basis of fertility in crosses.     

Integument and the Environment Glandular Composition, Function, and Evolution

SYNOPSIS Integumcntirv secietory cells and glands inveitebiateanimals are systemati cally surveyed and basic attnbutes ofthen adaptive evolution are outlined Moi phogenetic lines ofsecretory epideimal cells are fundamentaland present a pnmaiydichotomy between mucous and piotcinaceous stem lines Adaptiveevolution of integumentary glandulir cells can not be sepaiatedfrom the cytogenesis and evolution of other synthetically activeepideimal cells including thosewhich seciete without havinga glandulii moiphology Glandular microevolutionny patterns aiecoirelated with evolving intciactions between enviionment andoiganism and aie mterpietible only on the basis of studies lntegiaungthe appioaches ind techniques of diffciuit zoological spornllics     

The Development of the Integument Spatial, Temporal, and Phylogenetic Factors

SYNOPSIS The development of hair teeth and feathers is leviewedin the context ot experimental manipulation of dermal epideimalinteractions The inductive role of the del mis is described,and the consequences of altering the ages and sources of theinteracting tissue components is demonstrated The importanceof examining the developmental capibilities of these tissuesafter disruption of the dermal epidermal inteiface as well asin intact explants is discussed In addition the role of thebasement membrane m establishing and stabilizing integumentaldenvatrves and the role of collagen synthesis and depositionisexamined     

The Structure and Permeability of Integument

SYNOPSIS. The skin is a heterogeneous, multimembrane systemwith multiple diffusion pathways and potentially numerous rate-limitingbarriers for specific molecules that are exchanged with theenvironment. A broad survey of animals indicates that integumentarycoverings are morphologically, biochemically and embryologicallydiverse but with common themes of adaptation. The evolutionaryproliferation of intercellular junctions, fibrous or mineralizedprotective barriers, and lipoid waterproofing barriers emphasizethe generality of diffusion limitations. However, the regulationof specific exchange processes such as the flux rates of respiratorygases entails a complex interaction of multiple factors affectingboth diffusion and perfusion limitations. Consideration of specificpathways and rate limitations for diffusion of various substancessuggests that the permeation of skin by specific molecules canbe partially independent of other exchange processes. Our understandingof regulated permeability is, however, lacking in mechanisticand integrated analysis in most cases. Comprehensive understandingof the integument as a regulatory pathway of communication withthe environment will require comparative studies of specifictransport pathways, their rate-limiting resistances, and theinteractions as well as individual regulation of transportedmolecules.     

高等植物珠被绒毡层的研究

绒毡层是植物孢子体向配子体世代转换的"哺乳组织",其研究对于揭示植物配子体发育的调控机制具有重要意义。对花药绒毡层的发育过程已有一些研究,而对珠被绒毡层的研究积累相对较薄弱。对菊科(Compositae)、柴胡(Bupleu-rum)、大车前(Plantago major)、柱花草(Stylosanthes)等草本植物的研究表明,因珠被发育过程和结构复杂,珠被绒毡层结构也较花药绒毡层复杂,其发育模式因植物不同而异,有单珠被绒毡层和双珠被绒毡层两种类型;珠被绒毡层异常生长会导致胚珠败育。木本植物珠被绒毡层,特别是裸子植物的珠被绒毡层在国内外的研究报道不多。     

Lipoprotein lipase promoting agent, NO-1886, modulates adrenal functions: species difference in effects of NO-1886 on steroidogenesis.

A novel compound, NO-1886, which possesses a powerful lipoprotein lipase activity-increasing action, induces hypertrophy of adrenals in rats and hyperplasia of cortical cells in dogs. However, these effects were not observed in monkeys. We examined the effects of NO- 1886 on steroid hormone production by adrenocortical cells to clarify its effects on adrenal steroidogenesis. NO-1886 did not inhibit the steroid synthetic enzymes, including 3beta-hydroxysteroid dehydrogenase, 21-hydroxylase, 11beta-hydroxylase, or cholesterol side-chain cleavage enzymes. However, NO-1886 affected steroid production from adrenocortical cells in rats, dogs, monkeys, and humans in in vitro studies. These effects were almost completely reversed by the addition of 25-hydroxycholesterol or low-density lipoproteins to the reaction medium, but not reversed by the addition of high-density lipoproteins. These results suggest that NO-1886 affects the cholesterol pathways within the adrenocortical cells and inhibits steroidogenesis, causing a reduction of steroid hormone release from adrenocortical cells and resulting in hypertrophy of adrenals via feed-back mechanisms. However, its effect is not apparent in animals that use low-density lipoproteins as a source of adrenocortical steroidogenesis.     

五唇兰珠被细胞的超微结构观察

应用透射电镜对五唇兰(Doritis pulcherrima)珠被细胞进行超微结构观察。结果表明,授粉38d后,五唇兰外珠被细胞尚保持完好,而内珠被细胞开始退化;线粒体内嵴减少或消失,内质网上的核糖体数量减少,液泡增加,在新形成的液泡内含有膜状结构和模糊的细胞器,但核膜完整,与细胞程序死亡的部分特征相似。     

Ultrastructural Investigation of the Integument of Tubiluchus philippinensis (Priapulida, Tubiluchidae)

The integument of Tubiluchus philippinensis van der Land, 1984 has been investigated by means of scanning and transmission electron microscopy. The ultrastructure of the cuticle corresponds principally to what has been found in Priapulidae. The tumuli are mere cuticular thickenings. Setae, tubuli, flosculi and scalids are receptor organs. Tubuli additionally serve a second function: they produce a secretion. The male genital area is equipped with various receptor organs, the internal morphology of which has been described. All receptor cells are characterized by apical cilia, which may be surrounded by a circlet of microvilli. They sometimes bear a rather complicated rootlet apparatus.