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1.
An association between the scale-worm Malmgreniella cf. variegata and the ophiuroid Ophionereis annulata is reported for first time in the Mexican Pacific. The relationship was found in five localities across a total of 22 sites where O. annulata was collected. The polynoids collected were similar to the Western Atlantic scale-worm Malmgreniella variegata, which was previously recorded as commensal of O. annulata on the Pacific side of Panama, although they differ in colour pattern and the presence of notochaetae with a unidentate tip. The prevalence of infestation was 5 % and the intensity was 1.20. Experimental observations suggest that the behaviour of the scale-worm on O. annulata could be affected by light conditions, and that the commensal had a preference for its host over other ophiuroid species. More studies should be carried out to determine the taxonomic status of M. cf. variegata in the Eastern Pacific and to further elucidate the commensal–host relationship between this scale-worm and O. annulata.  相似文献   

2.
The excretory duct of pyriform glands in Araneus diadematus is connected to the secretory sac through an intermediary cell ring. Apices of these cells bear thick, long microvilli and cytoplasmic extensions containing microtubules in bundles, some of which are derived from normal basal bodies. These finger-like extensions lie between the cuticular intima and the secretory product; they are thought to protect the intima and to initiate moulding of the silk thread. Structural features of the duct cells suggest that the latter play a role in the control of the water content of the silk glue which is restricted to the last portion of the duct where numerous nerve endings are inserted between cells. It is evident that duct structure and chemical and physical characteristics of silk are correlated in all spider silk glands.  相似文献   

3.
Female insects generally store sperm received during mating in specific organs of their reproductive tract, i.e., the spermathecae, which keep the sperm alive for a long time until fertilization occurs. We investigated spermatheca morphology and ultrastructure in the psylloidean insect Trioza alacris (Flor, 1861 ) in which spheroidal sperm packets that we refer to as ‘spermatodoses’ are found after mating. The ectoderm‐derived epithelium of the sac‐shaped spermatheca that has a proximal neck, consists of large secretory and flat cuticle‐forming cells. Secretory cells are characterized by a wide extracellular cavity, bordered by microvilli, in which electron‐dense secretion accumulates before discharge into the spermathecal lumen. The cuticle‐forming cells produce the cuticular intima of the organ and a peculiar specialized apical structure, through which secretion flows into the lumen. At mating, the male transfers bundles of sperm cells embedded in seminal fluid into the spermathecal neck. Sperm cells proceed towards the spermathecal sac lumen, where they are progressively compacted and surrounded with an envelope that also encloses secretions of both male and female origin. We describe the formation of these sperm containing structures and document the contribution of the female secretion to spermatodose or female‐determined spermatophore construction. We also discuss the choice of the term ‘spermatodose’ for T. alacris and suggest it be used to refer to sperm masses constructed in the female reproductive organs, at least when they involve the contribution of female secretion. © 2011 Wiley Periodicals, Inc.  相似文献   

4.
Summary A closing apparatus of the Dufour gland is described in the formicine ant Formica sanguinea Latreille 1798. Four sets of muscles are involved, two of which directly attach to the slit-like duct. The latter shows a considerable cuticular thickening of its intima at this level. Ultrastructural observations reveal that the muscles are attached to a cuticula by means of intracellular microtubules in the duct cells. These microtubules run parallel to the myofilaments. Together with the increased contact area for muscular attachments they are believed to ensure the accurate muscular mechanism assuring a well-controlled spraying activity of this gland. Opening of the duct is probably achieved by active muscular contractions, while its closure may be achieved by a passive return to the rest position of the thickened cuticular intima.Research assistant of the Belgian National Fund for Scientific Research  相似文献   

5.
The insect tracheal system is an air-filled branching network of internal tubing that functions to exchange respiratory gases between the tissues and the environment. The light and electron-micrographs presented in this study show tracheae in the process of moulting, captured from the metathoracic hopping femur of a juvenile third instar locust (Locusta migratoria). The images provide evidence for the detachment of the cuticular intima from the tracheal epithelial cells, the presence of moulting fluid between the new and old cuticle layers, and the withdrawal of the shed cuticular lining through larger upstream regions of the tracheal system during moulting. The micrographs also reveal that the cuticular intima of the fine terminal branches of the tracheal system is cast at ecdysis. Therefore, the hypothesis that tracheoles retain their cuticle lining at each moult may not apply to all insect species or developmental stages.  相似文献   

6.
The postpharyngeal gland (PPG) plays a major role in the social integration of ant colonies. It had been thought to be restricted to ants but was recently also described for a solitary wasp, the European beewolf (Philanthus triangulum). This finding posed the question whether the gland has evolved independently in the two taxa or has been inherited from a common ancestor and is hence homologous. The latter alternative would be supported if a PPG was found in more basal taxa. Therefore, we examined a species at the base of the Apoidea, the solitary ampulicid wasp Ampulex compressa, for the existence of a PPG. Both sexes of this species possess a cephalic gland that branches off the posterior part of the pharynx, is lined by a cuticular intima and surrounded by a monolayered epithelium with the epithelial cells bearing long hairs. Most of these morphological characteristics conform to those of the PPG of ants and beewolves. Chemical analysis of the gland content revealed that it contains mainly hydrocarbons and that there is a congruence of the pattern of hydrocarbons in the gland, on the cuticle, and in the hemolymph, as has also been reported for both ants and beewolves. Based on these morphological and chemical results we propose that the newly described cephalic gland is a PPG and discuss its possible function in A. compressa. The present study supports the view of a homologous origin of the PPG in the aculeate Hymenoptera.  相似文献   

7.
Tropical theileriosis is a disease caused by infection with an apicomplexan parasite, Theileria annulata, and giving rise to huge economic losses. In recent years, parasite resistance has been reported against the most effective antitheilerial drug used for the treatment of this disease. This emphasizes the need for alternative methods of treatment. Enolase is a key glycolytic enzyme and can be selected as a macromolecular target of therapy of tropical theileriosis. In this study, an intron sequence present in T. annulata enolase gene was removed by PCR-directed mutagenesis, and the gene was first cloned into pGEM-T Easy vector and then subcloned into pLATE31 vector, and expressed in Escherichia coli cells. The enzyme was purified by affinity chromatography using Ni–NTA agarose column. Steady-state kinetic parameters of the enzyme were determined using GraFit 3.0. High quantities (~65 mg/l of culture) of pure recombinant T. annulata enolase have been obtained in a higly purified form (>95 %). Homodimer form of purified protein was determined from the molecular weights obtained from a single band on SDS-PAGE (48 kDa) and from size exclusion chromatography (93 kDa). Enzyme kinetic measurements using 2-PGA as substrate gave a specific activity of ~40 U/mg, K m: 106 μM, kcat: 37 s?1, and k cat/K m: 3.5 × 105 M?1 s?1. These values have been determined for the first time from this parasite enzyme, and availability of large quantities of enolase enzyme will facilitate further kinetic and structural characterization toward design of new antitheilerial drugs.  相似文献   

8.
The whole cuticle, perienteric fluid, and reproductive organs of Anisakis physeteris Baylis, 1923 from the sperm whale were analyzed for amino acid composition. Amino acid nitrogen per total nitrogen accounted for 96.2% in the cuticle. Corresponding values of TCA supernatant and precipitated fractions of perienteric fluid and reproductive organ were obtained. Proline, glycine, and arginine occurred abundantly in cuticle hydrolyzate. Lysine, glutamic acid, glycine, valine, leucine and histidine occounted for approximately 62% of total nitrogen in reproductive organ fractions. Differences were observed in the amounts of certain amino acids present in corresponding tissue of males and females as well as different tissue fractions from nematodes of the same sex, e.g., more serine in male cuticle than female, more proline in the protein of female reproductive organs than male; methionine present in cuticular protein and reproductive organ protein and nonprotein fractions but absent in perienteric fluid, and cystine in cuticular protein but not the other fractions. Untreated Anisakis hemolymph showed at least a 2-fold increase in ammonia in analyses made 2 and 10 days after bleeding. The relatively large ammonia content could have been in part the result of functional ornithine cycle and amino acid oxidase activity in vivo.  相似文献   

9.
《Insect Biochemistry》1989,19(1):41-46
The amino-terminal amino acid sequences for seven cuticular proteins from Hyalophora cecropia are reported. Proteins were purified by blotting two dimensional acrylamide gels onto acid-etched glass fiber filters, and the proteins were sequenced without further elution. The sequences of the serine-rich proteins from rigid cuticles revealed a new family of cuticular proteins, with features reminiscent of the amino-termini of certain vertebrate neurofilament proteins, members of the intermediate filament protein family which includes keratins. The proteins from flexible cuticles showed sequence similarity to proteins previously sequenced for Drosophila, Manduca and Sarcophaga. Proteins with identical electrophoretic mobility from two different metamorphic stages or from two anatomical regions within a single stage had identical amino-terminal sequences.  相似文献   

10.
11.
Sea slugs are interesting models to study post-copulatory sexual selection in simultaneous hermaphrodites due to the enormous variation of their reproductive systems. However, the knowledge of the functional morphology of their reproductive system is limited to few species, and it is rarely discussed in the context of sexual selection theory. In this study, we investigated the functional morphology of the sperm-containing chambers (i.e., ampulla, seminal receptacle, and bursa copulatrix) of the reproductive system of Okenia polycerelloides (Ortea & Bouchet, 1983), based on light, confocal, and electron microscopy. Although the morphology of the ampulla is similar to other species, indicating that it is a site for autosperm storage, we found some sperm facing the ampullar epithelium, a feature commonly regarded as characteristic of the seminal receptacle of sea slugs. The seminal receptacle of O. polycerelloides showed secretory activity and contained sperm with distribution and orientation suggestive of stratification of allosperm from distinct mating events, a feature that would affect sperm competition. The bursa copulatrix had epithelial cells with secretory and absorptive characteristics, and contained degraded sperm and yolk granules within its lumen. Comparative analyses of the contents of each organ demonstrated that sperm digestion occurs in the bursa copulatrix and affects sperm heads first, changing their morphology from slender and curved to shorter and ellipsoid before complete lysis. Although digestion and absorption of surplus sperm are currently the main hypothesized functions for the bursa copulatrix, its role in cryptic female choice should not be ruled out. The close structural connection between the seminal receptacle and bursa copulatrix, as well as their muscular walls, would enable control over the fate of the sperm received in each mating event, that is, storage or digestion.  相似文献   

12.
A laboratory colony of Oncopeltus fasciatus was found to be infected by Leptomonas oncopelti. The flagellates form a carpet attached to the cuticular intima of the rectal glands of adult bugs. The epithelial cells of these glands are characterized by infolded apical plasma membranes associated with mitochondria; the overlying cuticular intima shows endocuticular canals. The Leptomonas are attached by hemidesmosomes, located most often at the tip of the flagella. The Protozoa multiply by budding and the resultant straphangers cling to the parental flagellum. Adhesion of the flagellates to the cuticular lining is so strong that detaching flagellates carry with them the outer part of the epicuticle. Epicuticle repair presumably occurs through the endocuticular canals.  相似文献   

13.
T. annulata, an intracellular pathogenic parasite of the Aplicomplexa protozoan family infects bovine B-lymphocytes and macrophages. Parasitized cells that become transformed survive and proliferate independently of exogenous growth factors. In the present study, we used the isogenic non parasitized BL3 and parasitized TBL3 B cell lines, as a model to evaluate the contribution of two-major PI3-K- and PKA-dependent anti-apoptotic pathways in the survival of T. annulata parasitized B lymphocytes. We found that T. annulata increases PKA activity, induces over-expression of the catalytic subunit and down-regulates the pro-survival phosphorylation state of Akt/PKB. Consistent with a role of PKA activation in survival, two pharmacological inhibitors H89 and KT5720 ablate PKA-dependent survival of parasitized cells. To specifically inhibit PKA pro-survival pathways we linked the DPTsh1 peptide shuttle sequence to PKI5–24 and we generated DPT-PKI, a cell permeable PKI. DPT-PKI specifically inhibited PKA activity in bovine cell extracts and, as expected, also inhibited the PKA-dependent survival of T. annulata parasitized TBL3 cells. Thus, parasite-dependent constitutive activation of PKA in TBL3 cells generates an anti-apoptotic pathway that can protect T. annulata-infected B cells from apoptosis. These results also indicate that DPT-PKI could be a powerful tool to inhibit PKA pathways in other cell types.  相似文献   

14.
The spermatheca of Melanoplus sanguinipes consists of a preapical and an apical diverticulum, and a long, thin ductus seminalis. Histologically, the three components are identical. The wall of the spermatheca includes a basement membrane, secretory and epithelial cells, and a cuticular intima. Small, discrete bundles of muscle occur outside the basement membrane. In each secretory cell is a large central cavity which connects with a cuticular channel (efferent ductule) running through the epithelial cell to the spermathecal lumen. During sexual maturation, light- and dark-staining vesicles accumulate in the secretory cells and discharge their contents into the central cavity. Simultaneously, glycogen accumulates in the epithelial cells. Allatectomy of newly emerged females renders the secretory cells unable to produce material, an effect which can be reversed by topical application of synthetic juvenile hormone. The secretion contains protein and acidic mucopolysaccharide. After insemination the quantities of secretion in the lumen and of glycogen in the epithelial cells diminish in the preapical diverticulum where almost all sperm are stored. As the number of sperm declines, the secretion and glycogen are replenished.  相似文献   

15.
TTLL5/STAMP (tubulin tyrosine ligase-like family member 5) has multiple activities in cells. TTLL5 is one of 13 TTLLs, has polyglutamylation activity, augments the activity of p160 coactivators (SRC-1 and TIF2) in glucocorticoid receptor-regulated gene induction and repression, and displays steroid-independent growth activity with several cell types. To examine TTLL5/STAMP functions in whole animals, mice were prepared with an internal deletion that eliminated several activities of the Stamp gene. This mutation causes both reduced levels of STAMP mRNA and C-terminal truncation of STAMP protein. Homozygous targeted mutant (Stamptm/tm) mice appear normal except for marked decreases in male fertility associated with defects in progressive sperm motility. Abnormal axonemal structures with loss of tubulin doublets occur in most Stamptm/tm sperm tails in conjunction with substantial reduction in α-tubulin polyglutamylation, which closely correlates with the reduction in mutant STAMP mRNA. The axonemes in other structures appear unaffected. There is no obvious change in the organs for sperm development of WT versus Stamptm/tm males despite the levels of WT STAMP mRNA in testes being 20-fold higher than in any other organ examined. This defect in male fertility is unrelated to other Ttll genes or 24 genes previously identified as important for sperm function. Thus, STAMP appears to participate in a unique, tissue-selective TTLL-mediated pathway for α-tubulin polyglutamylation that is required for sperm maturation and motility and may be relevant for male fertility.  相似文献   

16.
A schizont antigen for the indirect fluorescent antibody test was prepared from an in vitro culture suspension of lymphoid cells infected with Theileria annulata macroschizonts. Two cattle recovered from T. annulata infection showed marked rises in antibody titer to this schizont antigen, with peak titers of 1:40,960 and 1:2560. Using sera from these recovered cattle, T. annulata cell culture schizont antigen was shown to cross-react markedly with Theileria parva and Theileria lawrencei cell culture schizonts and with Theileria mutans piroplasms in the indirect fluorescent antibody test. In contrast, using high-titer antisera to T. parva, T. lawrencei, and T. mutans, serological cross-reactions with T. annulata schizonts were only detected with T. parva and T. lawrencei antisera, and in both instances these were minimal. The value of the indirect fluorescent antibody test in the differential diagnosis of Theileria species pathogenic for cattle is discussed.  相似文献   

17.
The epithelium of seminal vesicles of seven species of Orthoptera Tettigonioidea was examined. Results revealed an epithelium that is always monolayered and devoid of cuticular intima, thus reflecting its mesodermic origin. In some species epithelial secretory activity is intense and seems to be effected via both apocrine and merocrine mechanisms. A peculiar characteristic observed in most of the species examined consists in the presence of spermiophagic activity, never previously recorded in insect seminal vesicles which have usually been attributed the function of synthesizing the substances that maintain sperm viable during their storage therein. The probable role of this spermiophagic activity in relation to the reproductive biology of Orthoptera Tettigonioidea is discussed.  相似文献   

18.
Although the fruit fly, Drosophila melanogaster, has emerged as a model system for human disease, its potential as a model for mammalian reproductive biology has not been fully exploited. Here we describe how Drosophila can be used to study the interactions between sperm and the female reproductive tract. Like many insects, Drosophila has two types of sperm storage organs, the spermatheca and seminal receptacle, whose ducts arise from the uterine wall. The spermatheca duct ends in a capsule-like structure surrounded by a layer of gland cells. In contrast, the seminal receptacle is a slender, blind-ended tubule. Recent studies suggest that the spermatheca is specialized for long-term storage, as well as sperm maturation, whereas the receptacle functions in short-term sperm storage. Here we discuss recent molecular and morphological analyses that highlight possible themes of gamete interaction with the female reproductive tract and draw comparison of sperm storage organ design in Drosophila and other animals, particularly mammals. Furthermore, we discuss how the study of multiple sperm storage organ types in Drosophila may help us identify factors essential for sperm viability and, moreover, factors that promote long-term sperm survivorship.  相似文献   

19.
The ultrastructure of the spermathecal epithelium of the African Migratory Locust Locusta migratoria migratorioides R. & F. (Orthoptera: Acrididae) was investigated with the aid of transmission and scanning electron microscopic methods. The unpaired spermatheca can be subdivided into a multiple coiled tube and a terminal bulb region with vestibule, small apical and extensive pre-apical diverticulum. The wall of the spermatheca consists of a chitin intima, a layer of epithelial cells with a distinct apical microvilli border and a layer of gland cells, whereby slender projections of the epithelial cells extend between the gland cells. Through extensive folding, the basal plasma membrane of the gland and epithelial cells form a huge labyrinth, which is bounded by a basal lamina. Extending into the above mentioned projections there are bundles of parallel-arrayed microtubules, which run perpendicular to the microvilli border of the epithelial cell. They end in the base region of the microvilli and in the basal labyrinth on hemidesmosomes and serve to provide a mechanically stressable anchorage for the epithelium. The gland cells show structures typical for the production of export proteins: ribosomes, rER, dictyosomes, as well as vesicles of different size and electron-density. Every gland cell contains an extracellular cavity, arising through invagination, which is coated with a microvilli border. Over an end-apparatus and a ductule joining onto it (also with chitin intima) the lumen of the extracellular cavity is connected with the spermathecal lumen. The release of secretions and other substances from the epithelium into the spermatheca lumen is as possible as the uptake of substances from the latter into the epithelium. Regional differences in the fine structure of the cuticular intima, epithelial and gland cells point to different functions of the epithelium in these regions.  相似文献   

20.
Electron micrographs of inseminated eggs of Hydroides hexagonus previously had shown that in the immediate vicinity of the penetrating spermatozoön a small portion of the vitelline membrane regularly was absent, and it had been suggested that this area was a hole made by lytic activity of the individual spermatozoön during the course of its passage through the membrane. This deduction would receive support if it could be established that a sperm entry hole does form in living material. During the present study a hole repeatedly observed and photographed in the membrane of living eggs was found to arise as the spermatozoön penetrated the membrane. Gently compressed eggs formed exovates only through this hole. The holes, and exovates, were not found except at sperm entry sites. It was concluded that this hole is the counterpart of the area from which the membrane is absent in the electron micrographs cited above, and that the spermatozoön makes this hole. In an electron micrograph two spermatozoa which had penetrated the membrane at separate but closely neighboring points now occupy a single hole. It is argued that if each spermatozoön had displaced the membrane mechanically to make its hole, then there should be two holes, with a partition of membrane between them, but if each had eroded the membrane by applying lysin, a single hole should have formed as the eroded areas expanded and finally merged into one. The latter view agrees with the facts of the electron micrograph. It is concluded that lysis is the most probable means by which the individual spermatozoön makes its hole.  相似文献   

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