Home About us Contact
|
Home About us Contact | ||
|
|
||
Residual Bodies (residual + body)
Selected AbstractsDynamic expression of the prion-like protein Doppel in ovine testicular tissueINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 3 2006Arild Espenes Summary Transgenic knockout of the gene encoding the prion-like protein Doppel (Dpl) leads to male infertility in mice. The precise role of Dpl in male fertility is still unclear, but sperm from Dpl-deficient mice appear to be unable to undergo the normal acrosome reaction that is necessary to penetrate the zona pellucida of the ovum. We have investigated the expression pattern and some biochemical properties of Dpl in sheep testicular tissue and spermatozoa. Neither the Dpl protein nor its mRNA was detected in pre-pubertal sheep testis. This was in contrast to the findings in adult rams where both Dpl mRNA and protein were present. The molecular mass and glycosylation pattern of sheep Dpl were similar to that of mice Dpl. The Dpl protein was detected in the seminiferous epithelium during the two final (7 and 8) and the two initial (1 and 2) stages of the spermatogenic cycle in a characteristic pattern. In stage 8, an intense brim of granular Dpl-immunoreactivity associated with maturation phase spermatids was observed, while after the release of spermatozoa in stages 1 and 2, the Dpl-staining was disseminated more diffusely in the epithelium, reaching the basal lamina. From stage 3 to stage 6, Dpl-immunoreactivity could not be detected, indicating that the Dpl protein had disappeared between stages 2 and 3. Dpl was not detected on ejaculated spermatozoa. These patterns of staining indicate that Dpl is enriched in residual bodies, which are phagocytosed and destroyed by Sertoli cells after release of sperm into the lumen of the seminiferous tubule. [source] Enzymatic and immunochemical evaluation of phospholipid hydroperoxide glutathione peroxidase (PHGPx) in testes and epididymal spermatozoa of rats of different agesINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 2 2002Federica Tramer Selenium (Se) and selenoproteins such as glutathione peroxidases are necessary for the proper development and fertilizing capacity of sperm cells. Phospholipid hydroperoxide glutathione peroxidase (PHGPx, E.C. 1.11.1.12) is a monomeric seleno-enzyme present in different mammalian tissues in soluble and bound form. Its function, like the other glutathione peroxidases, was originally viewed as a protective role against hydroperoxides, but direct and indirect evidence indicates that it has additional regulatory roles. PHGPx is present in testis cells and sperm cells, and its appearance is hormone regulated. We present here biochemical data, which clearly indicate that the enzyme specific activity in rat is age-dependent during the life-span monitored (from 36 to 365 days), with a maximum at 3 months of age in the testis germ cells and at 6 months of age in the isolated epididymal sperm cells. Western blotting and immunocytochemical analysis by means of anti-PHGPx antibodies show the different distribution and the strong binding of PHGPx in the testes and sperm cell subcellular compartments (nucleus, acrosome, mitochondria and residual bodies) of rats of different age. The presence of the protein exhibits in the testis cells a pattern different from that of the catalytic activity, with a maximum at 6 months of age. The subcellular distribution of PHGPx is qualitatively, but not quantitatively, unchanged during ageing. These different behaviours are compared and discussed. [source] Apoptotic-like morphology is associated with annual synchronized death in kleptoplastic sea slugs (Elysia chlorotica)INVERTEBRATE BIOLOGY, Issue 2 2003William L. Mondy Abstract. Certain digestive cells of the opisthobranch mollusc, Elysia chlorotica, contain functional chloroplasts which they steal from the filamentous alga, Vaucheria litorea. The adult portion of the life cycle of the slug lasts for ,10 months and is completely synchronized among individuals. All the adults die each year within a few weeks of each other. We have examined the microscopic morphology of the slugs near the end of the life cycle. Light microscopy demonstrated an absence of chloroplasts in most of the digestive epithelial cells, the appearance of many crypt cells containing residual bodies and an invasion of the blood sinuses by neoplastic morula-like cells as the animals die. Electron microscopy revealed a degeneration of the digestive diverticulum which had several morphological characteristics in common with apoptosis: expansion of the endoplasmic reticulum and Golgi apparatus, DNA fragmentation, formation of primary lysosomes, and condensation of chromatin. These are followed by fragmentation of the nucleus and cytoplasm into autosomes merging to form a large central autolysosome. In addition in the aging slugs, the plastids begin to degenerate until none were left in the digestive epithelial cells and the central autolysosome contained numerous viral particles. [source] Food plaquette digestion in the ciliated protozoan Hyalophysa chattoniINVERTEBRATE BIOLOGY, Issue 2 2001Stephen C. Landers Abstract. The digestion of food plaquettes in the ciliated protozoan Hyalophysa chattoni was analyzed by light and electron microscopy. Through the use of nigrosin as a tracer for light microscopy and polystyrene microparticles for electron microscopy, we have demonstrated that food plaquettes transform to late-stage digestive vesicles. Eventually, in the phoront, some of the late-stage vesicles merge to form larger fusion vesicles, which are retained in the peripheral cytoplasm of the ensuing feeding stage. After the feeding stage settles and encysts, these vesicles are either retained by the daughter cells or are left in the divisional cyst as residual bodies. Food plaquettes, digestive vesicles, and fusion vesicles stain positively with neutral red and acridine orange, indicating an acidic pH. These results portray a unique digestive pathway in which stored, undigested material is reorganized into larger fusion vesicles as the cell prepares for additional feeding. [source] Complementary DNA cloning of rat spetex-1, a spermatid-expressing gene-1, encoding a 63 kDa cytoplasmic protein of elongate spermatidsMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2004Hiroshi Iida Abstract We used differential display in combination with complementary DNA (cDNA) cloning approach to isolate a novel rat gene designated as spetex-1, which had an open reading frame of 1,668-length nucleotides encoding a protein of 556 amino acids. Spetex-1 mRNA was highly expressed in testis, and weekly expressed in lung, intestine, and spleen. Spetex-1 expression in the rat testes was detected first at 3 weeks in postnatal development and continued to be detected up to adulthood. A search in the databases showed that the amino acid sequence of spetex-1 was 82% identical to that of its mouse homologue found in the databases. Both rat spetex-1 and the mouse homologue contained Ser-X (X,=,His, Arg, or Asn) repeats in the middle portion of the proteins. In situ hybridization revealed that spetex-1 mRNA was expressed in haploid spermatids of step 7,18 within the seminiferous epithelium. Immunohistochemical analysis with confocal laser-scanning microscopy demonstrated that spetex-1 protein was not expressed in spermatogonia, spermatocytes, and round spermatids in adult rat testis, but was specifically detected in the residual cytoplasm of elongate spermatids of step 15,18 as well as in residual bodies engulfed by Sertoli cells. We interpreted these data as a potential role of spetex-1 in spermatogenesis, especially in cell differentiation from late elongate spermatids to mature spermatozoa. Mol. Reprod. Dev. 68: 385,393, 2004. © 2004 Wiley-Liss, Inc. [source] Study of the mouse sortilin gene: Effects of its transient silencing by RNA interference in TM4 sertoli cellsMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2004Jibin Zeng Abstract Using databases of the mouse genome in combination with a sequence deduced from a mouse sortilin cDNA originated in our laboratory, we found the sortilin gene to map to a region of chromosome 3. The mouse sortilin gene contains 19 short exons separated by introns of various sizes. The study elucidated the exon-intron boundaries. Some introns extend over more than 24 kb. In the cytoplasmic domain of the translation product, we found a dileucine motif and three other motifs known to constitute the active sorting signal of the mannose 6-phosphate receptor (M6P-R). We also tested the hypothesis that sortilin is involved in the sorting of prosaposin (SGP-1) to the lysosomes. Prosaposin was initially identified in Sertoli cells, found in large amounts in the lysosomal compartment and implicated in the degradation of residual bodies released by the spermatids during spermiation. Interestingly, the targeting of prosaposin to the lysosomes is independent of the M6P-R. This investigation demonstrated that sortilin was required for the trafficking of prosaposin to the lysosomes in TM4 cells. The requirement of sortilin was shown using a siRNA probe to block the translation of sortilin mRNA. Sortilin-deficient cells were not able to route prosaposin to the lysosomal compartment but continue to transport cathepsin B, since this hydrolase uses the M6P-R to be routed to the lysosomes. These results indicate that sortilin appears to be involved in the lysosomal trafficking of prosaposin. Mol. Reprod. Dev. 68: 469,475, 2004. © 2004 Wiley-Liss, Inc. [source] Tryptamine induces cell death with ultrastructural features of autophagy in neurons and glia: Possible relevance for neurodegenerative disordersTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 9 2006Federico Herrera Abstract Tryptamine derivatives are a family of biogenic amines that have been suggested to be modulators of brain function at physiological concentrations. However, pharmacological concentrations of these amines display amphetamine-like properties, and they seem to play a role in brain disorders. Amphetamines induce autophagy in nerve cells, and this type of cell death has also been involved in neurodegenerative diseases. In the present work, we clearly demonstrate for the very first time that high concentrations of tryptamine (0.1,1 mM) induce autophagy in HT22 and SK-N-SH nerve cell lines and in primary cultures of astrocytes, glial cells being less sensitive than neurons. Ultrastructural cell morphology shows all of the typical hallmarks of autophagy. There is no nuclear chromatin condensation, endoplasmic reticulum and mitochondria are swollen, and a great number of double-membraned autophagosomes and residual bodies can be shown in the cytoplasm. Autophagosomes and residual bodies contain mitochondria, membranes, and vesicles and remain unabridged until the cell membrane is disrupted and the cell dies. The same results have been found when cells were incubated with high concentrations of 5-methoxytryptamine (0.1,1 mM). Our results establish a possible link between the role of tryptamine derivatives in brain disorders and the presence of autophagic cell death in these kinds of disorders. Anat Rec Part A, 288A:1026,1030, 2006. © 2006 Wiley-Liss, Inc. [source] Widespread hermaphroditism in freshwater gastrotrichsINVERTEBRATE BIOLOGY, Issue 4 2001Mitchell J. Weiss Abstract. Freshwater members of the phylum Gastrotricha were long thought to lack male gametes and to exist exclusively as parthenogenetic females. The surprising 1978 discovery of sperm in the common species Lepidodermella squamata raised the question of how many other freshwater gastrotrichs might likewise be hermaphroditic. In a comparative study of species from across both major families, sperm have been found in every species examined intensively. They were detected in 19 species of Chaetonotidae (from Aspidiophorus, Chaetonotus, Heterolepidoderma, Ichthydium, Lepidodermella, and Polymerurus) and 3 species of Dasydytidae (from Haltidytes, Setopus, and Stylochaeta), characteristically occurring ventrally in single unilateral or (more often) 2,12 bilateral packets. Their shape ranges from filiform (length in Chaetonotus bisacer, ,40 ,m) to rodlike, spindlelike, oval, and possibly spherical (some in Stylochaeta scirtetica measure only 1 ,m). With light microscopy, a dense nucleus appears to fill the entire volume of these aflagellate cells. Spermatogenesis within cysts (maximally, 16 sperm/clone) is evidently characteristic of both families, each cyst generating one large residual body. Sperm-bearers display oocytes with sometimes distinctive cytoplasmic elements and a posterior X-organ whose organization can be complex. Evidence supports an unusual life cycle in which parthenogenesis is followed by simultaneous hermaphroditism. These findings may illuminate the reproductive characters as well as ancestry of marine and brackish-water taxa of Chaetonotida. [source] | ||||||||||