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31.
Hemolin, a member of the immunoglobulin protein superfamily, functions in Lepidoptera as an opsonin in defence against potential pathogens and seems to play a role in tissue morphogenesis. We show that hemolin gene is expressed in several organs of Galleria mellonella larvae, including the nervous system and the silk glands. The expression in the silk glands of the wandering larvae and their isolated abdomens is enhanced within 6 h after an injection of bacteria, lipopolysaccharides, or peptidoglycans. The magnitude of silk gland response to bacterial challenge is similar to that seen in the fat body. A profound rise of hemolin expression without bacterial inoculation occurs in the silk glands of isolated abdomens when they are induced to pupate by a topical application of 20-hydroxyecdysone (20E). The induction of pupation is associated with silk gland programming for disintegration by apoptosis and phagocytosis. Administration of a juvenile hormone agonist prevents pupation and abolishes the stimulatory 20E effect on the hemolin expression. Hemolin protein can be immunodetected in the silk glands as well as in the spun-out cocoon silk. The results suggest that silk glands are a component of the insect immune system and that hemolin may mark the apoptic cells for the elimination by hemocytes. 相似文献
32.
不同生态环境野生大豆的结构比较研究 总被引:4,自引:0,他引:4
对生长在不同生态环境的蝶形花科Fabaceae 大豆属Glycine 的两个野生大豆G.soja 品系进行了扫描电镜观察及比较研究.结果表明,生长在盐渍生态环境的野生大豆茎和叶体表都具有盐腺,盐腺圆球型,基部有一个小柄,着生在盐生野生大豆茎、叶表皮外切向壁的胞间层处.幼嫩的盐腺靠泌盐孔泌盐,成熟的盐腺靠整体破碎释盐.而生长在黑土地生态环境的野生大豆的茎和叶外切向壁未发现有泌盐的盐腺,其茎叶的表皮都呈现出平滑状态.因此两种不同生态环境的同科同属植物在微观结构上显示出明显差异. 相似文献
33.
Nadim Cortas May Arnaout John Salon I. S. Edelman 《The Journal of membrane biology》1989,108(2):187-195
Summary To characterize the molecular properties conveyed by the isoforms of the subunit of Na,K-ATPase, the two major transepithelial transporting organs in the brine shrimp (Artemia salina), the salt glands and intestines, were isolated in pure form. The isoforms were quantified by ATP-sensitive fluorescein isothiocyanate (FITC) labeling. The salt gland enzyme exhibits only the 1 isoform, whereas the intestinal enzyme exhibits both the 1 and the 2 isoforms. After 32 hours of development, Na,K-ATPase activity [in mol Pi/mg protein/hr (1u)] in whole homogenates was 32±6 in the salt glands and 12±3 in the intestinal preparations (mean±sem). The apparent half-maximal activation constants (K
1/2) of the salt gland enzyme as compared to the intestinal enzyme were 3.7±0.6mm
vs. 23.5±4mm (P<0.01) for Na+, 16.6±2.2mm
vs. 8.29±1.5mm for K+ (P<0.01), and 0.87±0.8mm
vs. 0.79±1.1mm for ATP (NS). The apparentK
i's for ouabain inhibition were 1.1×10–4
m
vs. 2×10–5
m, respectively. Treatment of whole homogenates with deoxycholic acid (DOC) produced a maximal Na,K-ATPase activation of 46% in the salt gland as compared to 23% in the intestinal enzyme. Similar differences were found with sodium dodecyl sulfate (SDS). The two distinct forms of Na,K-ATPase isolated from the brine shrimp differed markedly in three kinetic parameters as well as in detergent sensitivity. The differences inK
1/2 for Na+ and K+ are more marked than those reported for the mammalian Na,K-ATPase isoforms. These differences may be attributed to the relative abundances of the subunit isoforms; other potential determinants (e.g. differences in membrane lipids), however, have not been investigated.During the tenure of an Educational Commission For Foreign Medical Graduates Visiting Associate Professorship. 相似文献
34.
South A Stanger-Hall K Jeng ML Lewis SM 《Evolution; international journal of organic evolution》2011,65(4):1099-1113
The beetle family Lampyridae (fireflies) encompasses ~100 genera worldwide with considerable diversity in life histories and signaling modes. Some lampyrid males use reproductive accessory glands to produce spermatophores, which have been shown to increase female lifetime fecundity. Sexual dimorphism in the form of neotenic and flightless females is also common in this family. A major goal of this study was to test a hypothesized link between female flight ability and male spermatophore production. We examined macroevolutionary patterns to test for correlated evolution among different levels of female neoteny (and associated loss of flight ability), male accessory gland number (and associated spermatophore production), and sexual signaling mode. Trait reconstruction on a molecular phylogeny indicated that flying females and spermatophores were ancestral traits and that female neoteny increased monotonically and led to flightlessness within multiple lineages. In addition, male spermatophore production was lost multiple times. Our evolutionary trait analysis revealed significant correlations between increased female neoteny and male accessory gland number, as well as between flightlessness and spermatophore loss. In addition, female flightlessness was positively correlated with the use of glows as female sexual signal. Transition probability analysis supported an evolutionary sequence of female flightlessness evolving first, followed by loss of male spermatophores. These results contribute to understanding how spermatophores have evolved and how this important class of seminal nuptial gifts is linked to other traits, providing new insights into sexual selection and life-history evolution. 相似文献
35.
Summary Reproductive isolation in termites is not well known. Our study carried out on two sympatric species from northern Vietnam, Macrotermes annandalei and M. barneyi, showed that dispersal flights and sex pheromones were two important factors in their reproductive isolation. These fungus-growing termites were isolated, partially due to the timing of their respective dispersal flights. M. annandalei flew the first day after rain, while the flights of M. barneyi occurred the second day after rain. However, the flights can also be simultaneous in the two species. Sex pheromones of M. annandalei and M. barneyi were shown to be species-specific. In both species, they were secreted by females from two glandular sources, from tergal glands located on tergite 6 to 10 in M. annandalei and tergite 5 to 10 in M. barneyi, and from posterior sternal glands located on sternite 6 and 7 in both species. These posterior sternal glands, found for the first time in the Termitidae, were sex-specific glands. Although not fully identified, sex pheromones of M. annandalei and M. barneyi were clearly different from the trail-following pheromone secreted by the sternal gland stricto sensu located on the sternite 5. These results show that in termites, the sexual behaviour, the glandular origin of sex pheromones and their role in reproductive isolation greatly vary depending on the species and deserve to be more extensively studied.Received 8 April 2003; revised 1 September 2003; accepted 10 September 2003. 相似文献
36.
Ahmed E. Hegab Vi Luan Ha Yasser S. Attiga Derek W. Nickerson Brigitte N. Gomperts 《Journal of visualized experiments : JoVE》2012,(67)
The large airways are directly in contact with the environment and therefore susceptible to injury from toxins and infectious agents that we breath in 1. The large airways therefore require an efficient repair mechanism to protect our bodies. This repair process occurs from stem cells in the airways and isolating these stem cells from the airways is important for understanding the mechanisms of repair and regeneration. It is also important for understanding abnormal repair that can lead to airway diseases 2. The goal of this method is to isolate a novel stem cell population from the mouse tracheal submucosal gland ducts and to place these cells in in vitro and in vivo model systems to identify the mechanisms of repair and regeneration of the submucosal glands 3. This production shows methods that can be used to isolate and assay the duct and basal stem cells from the large airways 3.This will allow us to study diseases of the airway, such as cystic fibrosis, asthma and chronic obstructive pulmonary disease. Currently, there are no methods for isolation of submucosal gland duct cells and there are no in vivo models to study the regeneration of submucosal glands. 相似文献
37.
Bicarbonate and chloride secretion in Calu-3 human airway epithelial cells 总被引:23,自引:0,他引:23 下载免费PDF全文
Devor DC Singh AK Lambert LC DeLuca A Frizzell RA Bridges RJ 《The Journal of general physiology》1999,113(5):743-760
Serous cells are the predominant site of cystic fibrosis transmembrane conductance regulator expression in the airways, and they make a significant contribution to the volume, composition, and consistency of the submucosal gland secretions. We have employed the human airway serous cell line Calu-3 as a model system to investigate the mechanisms of serous cell anion secretion. Forskolin-stimulated Calu-3 cells secrete HCO-3 by a Cl-offdependent, serosal Na+-dependent, serosal bumetanide-insensitive, and serosal 4,4'-dinitrostilben-2,2'-disulfonic acid (DNDS)-sensitive, electrogenic mechanism as judged by transepithelial currents, isotopic fluxes, and the results of ion substitution, pharmacology, and pH studies. Similar studies revealed that stimulation of Calu-3 cells with 1-ethyl-2-benzimidazolinone (1-EBIO), an activator of basolateral membrane Ca2+-activated K+ channels, reduced HCO-3 secretion and caused the secretion of Cl- by a bumetanide-sensitive, electrogenic mechanism. Nystatin permeabilization of Calu-3 monolayers demonstrated 1-EBIO activated a charybdotoxin- and clotrimazole- inhibited basolateral membrane K+ current. Patch-clamp studies confirmed the presence of an intermediate conductance inwardly rectified K+ channel with this pharmacological profile. We propose that hyperpolarization of the basolateral membrane voltage elicits a switch from HCO-3 secretion to Cl- secretion because the uptake of HCO-3 across the basolateral membrane is mediated by a 4,4 '-dinitrostilben-2,2'-disulfonic acid (DNDS)-sensitive Na+:HCO-3 cotransporter. Since the stoichiometry reported for Na+:HCO-3 cotransport is 1:2 or 1:3, hyperpolarization of the basolateral membrane potential by 1-EBIO would inhibit HCO-3 entry and favor the secretion of Cl-. Therefore, differential regulation of the basolateral membrane K+ conductance by secretory agonists could provide a means of stimulating HCO-3 and Cl- secretion. In this context, cystic fibrosis transmembrane conductance regulator could serve as both a HCO-3 and a Cl- channel, mediating the apical membrane exit of either anion depending on basolateral membrane anion entry mechanisms and the driving forces that prevail. If these results with Calu-3 cells accurately reflect the transport properties of native submucosal gland serous cells, then HCO-3 secretion in the human airways warrants greater attention. 相似文献
38.
39.
KALYANI RAMASUBRAMANIAM 《Invertebrate reproduction & development.》2013,57(6):333-346
Histochemical investigations of the secretions of reproductive glands—albumen gland, apical uterus, basal uterus and prostate gland—indicate the presence of galactogen in the albumen gland, acid mucopolysaccharide in the apical uterus, and lipoprotein in the basal uterus and prostate gland of A. fulica. The proteinaceous secretions produced by the glands do differ in their terminal reactive sites. Intense alkaline phosphatase reaction is found in albumen gland and apical uterus; carbonic anhydrase activity could be detected mainly in the uterine glands. The cyclical secretory activity of the reproductive glands has been studied preparatory to egg-laying and in the spent phase. Histochemical characteristics of the egg envelopes—albumen, shell membrane and egg-shell—suggest a possible sequential deposition of glandular products during the descent of eggs through the repv. ductive tract. The factors contributing to the stability and resistant nature of the egg envelopes, and the possible role of nutritive materials contained in reproductive gland secretions in the development of the embryo (even while the eggs are inside the uterus), are discussed. 相似文献
40.