Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Circular DNA was isolated from mitochondrial fractions of ram spermatozoa by SDS treatment followed by convex sucrose gradient centrifugation. The DNA had a contour length of 5.0 micron. Its buoyant density was 1.6983 g cm-3, which was smaller than two nuclear DNA components with buoyant densities of 1.6999 and 1.7156 g cm-3, found in ram spermatozoa. The Tm of the mitochondrial DNA was 69.7 degrees C. The mole fraction G+C calculated from the buoyant density and melting temperature was 39.1% and 38.6%, respectively.
 ...
PMID:Ram sperm mitochondrial DNA. 61 Aug 81

A method for isolation of plasma membrane vesicles from human and boar spermatozoa using nitrogen cavitation is described. The purity of the preparations were assessed by electron microscopy, marker enzyme assay and the sedimentation characteristics of fused plasma membrane-acrosomal membrane vesicles in sucrose gradients. PAGE-SDS profiles of plasma membrane polypeptides from boar spermatozoa were significantly different from those of human spermatozoa. Differences in electrophoretic profiles of polypeptides from different regions of the spermatozooon were also observed.
 ...
PMID:Isolation and characterization of membrane vesicles from human and boar spermatozoa: methods using nitrogen cavitation and ionophore induced vesiculation. 71 84

The perforatorium of rat spermatozoa was isolated and its protein composition determined. SDS-polyacrylamide gel electrophoresis showed that the organelle is composed of a single polypeptide component with a molecular weight of 13,000. The perforatorium becomes more resistant to solubilization during epididymal transit due to an apparent increase in disulphide bond content. Amino acid analysis of the perforatorium polypeptide revealed a content of 6-5% cysteine.
 ...
PMID:Isolation and characterization of the perforatorium of rat spermatozoa. 95 29

Possum spermatozoa undergo a distinctive process of maturation in the epididymis, as shown by change in the properties of the sperm surface, by modification of their morphology and by their increasing capacity for progressive motility. Modification of the sperm surface over the head and tail is demonstrated by the different affinities of sperm from successive regions of the epididymis for FITC-conjugated wheat germ agglutinin and concanavalin A, and for cationic ferric oxide colloidal particles. Changes in sperm head morphology are caused by (1) a dramatic reshaping and consolidation of the acrosome in which excess plasma membrane overlying it is sloughed as a cluster of vesicles, (2) a reorientation of the nucleus almost parallel to the axis of the tail and (3) distal movement of the droplet from its initial envelopment of the nucleus to an eccentric position on the anterior segment of the midpiece. Spermatozoa released from the testis and caput epididymidis are essentially immotile or exhibit only lazy uncoordinated movements, whereas many from the corpus and most from the more distal regions of the epididymis display an energetic, progressive motility imparted by a rapid and stiff tail beat of narrow arc. This maturation of the capacity for motility is accompanied by an enhanced stability of the dense fibers and sheath, which became more resistant to the disruptive action of SDS and DTT, and by changes in the ultrastructure of the sperm tail. These include modification of the matrix of the mitochondria and also an unusual differentation of the midpiece into two distinct segments. The anterior segment is defined by profuse peri-mitochondrial stacks of membranes which developed as spermatozoa pass through the epididymis. These membranes, although prominent in mature spermatozoa fixed in situ, appear sparse and disorganised in spermatozoa fixed after 15 to 30 minutes of active motility in physiological medium, suggesting their possible utilisation in motile spermatozoa. The posterior segment is characterised by a thick peri-mitochondrial cytoplasmic sleeve, by spirally arranged parallel fibrous bands immediately beneath the plasma membrane and, subsequently, as spermatozoa pass into the lower corpus epididymidis, by rows of flask-shaped surface invaginations which develop between the spiral bands. Despite broad similarities in the features of sperm maturation in this marsupial and in eutherian mammals, there are distinct differencesin the structural organisation of their spermatozoa, particularly in the pserm head. Until more is known of the details of fertilisation in marsupials the significance of these differences will remain unclear.
 ...
PMID:The features of sperm maturation in the epididymis of a marsupial, the brushtailed possum Trichosurus vulpecula. 100 39

Our previous study suggested that a chymotrypsin-like protease was involved in the motility of chum salmon sperm (Inaba K, Morisawa M, Biomed Res (1991) 12, 435-437). In this study, we examined the peptidase activity of demembranated sperm of chum salmon using ten synthetic peptides. When spermatozoa were treated with 0.04% Triton X-100 for extracting the plasma membrane and the suspension was separated into the Triton-soluble and insoluble fractions by centrifugation, only the hydrolytic activity towards succinyl (Suc)-Leu-Leu-Val-Tyr-4-methylcoumaryl-7-amide (MCA), a typical substrate for chymotrypsin-like protease, was mostly retained in the insoluble fraction. The bulk of the activities toward other substrates was detected in the soluble fraction. Flagellar axonemes isolated from demembranated sperm showed considerable hydrolytic activity toward Suc-Leu-Leu-Val-Tyr-MCA and the activity was still retained in the axoneme even after further washing. The hydrolysis was activated by a low concentration of SDS, suggesting that the protease associated with the axonemes is a multicatalytic ATP-dependent proteinase (proteasome). Motility of demembranated sperm was inhibited by Suc-Leu-Leu-Val-Tyr-MCA in an ATP-concentration-dependent manner. These results suggest that proteasomes associated with flagellar axoneme regulate flagellar motility.
 ...
PMID:Chymotrypsin-like protease activity associated with demembranated sperm of chum salmon. 130 78

We characterized receptors specific for sperm-activating peptide III (SAP-III: DSDSAQNLIQ) in spermatozoa of the sand dollar, Clypeaster japonicus, using both binding and cross-linking techniques. Analyses of the data obtained from the equilibrium binding of a radiolabeled SAP-III analogueto C. japonicus spermatozoa, using Klotz, Scatchard and Hill plots, showed the presence of two classes of receptors specific for SAP-III in the spermatozoa. One of the receptors (high-affinity) had a Kd of 3.4 nM and 3.4 x 10(4) binding sites/spermatozoon. The other receptor (low-affinity) had a Kd of 48 nM, with 6.1 x 10(4) binding sites/spermatozoon. The Kd of the high-affinity receptor was comparable to the median effective concentration of the intracellular-pH-increasing activity of SAP-III and that of the low-affinity receptor was comparable to the median effective concentration of the cellular-cGMP-elevating activity of the peptide. In addition, Scatchard and Hill plots of the data suggested the existence of positive cooperativity between the high-affinity members. Similar results were also obtained from a binding experiment using a sperm-membrane fraction prepared from C. japonicus spermatozoa. The incubation of intact spermatozoa or sperm plasma membranes with the radioiodinated SAP-III analogue and a chemical cross-linking reagent, disuccinimidyl suberate, resulted in the radiolabeling of three proteins with molecular masses of 126, 87 and 64 kDa, estimated by SDS/PAGE under reducing conditions.
 ...
PMID:Two classes of receptor specific for sperm-activating peptide III in sand-dollar spermatozoa. 131 39

Specific binding sites for atrial natriuretic factor (ANF) have been detected and localized in viable human spermatozoa through radioreceptor analysis and autoradiography, respectively. Radiotracer uptake was time and concentration dependent. Scatchard analysis of saturation data showed a single class of ANF receptors with a kd of 2.5 nM and a Bmax of 1.03 fmol/10(6) sperm 2.5 min-1, corresponding to about 620 molecules per sperm. Nonreducing SDS-PAGE analysis after covalent cross-linking of sperm bound 125I-ANF evidenced a single displaceable (i.e., specific) band with an apparent molecular weight of 135-140kD. In 125I-ANF bound spermatozoa, optical autoradiography showed an exclusive distribution of silver grains covering the midpiece region. The effects of ANF binding on ionic homeostasis and cyclic nucleotide metabolism, which modulate a number of sperm cellular processes, could make this factor play outstanding roles in gamete physiology.
 ...
PMID:Identification and localization of atrial natriuretic factor receptors in human spermatozoa. 132 61

The aim of the present work was to compare the structure and protein composition of centrioles from spermatozoa of sturgeon and salmon fishes. The total protein content of the extracted fractions was studied by Na-SDS electrophoresis. Proteins with molecular weights from 15 to 170 kDa were detected. In both cases the major protein of centrioles is a protein with a molecular weight equal to that of tubulin. A protein with the molecular weight corresponding to actin was also detected. In both cases the ATPase activity stimulated by Ca2+ and Mg2+ ions was revealed. Electron microscopic studies showed differences in the ultrastructure of centrioles from sturgeon and salmon spermatozoa.
 ...
PMID:[Comparative study of the structure and protein composition of spermatozoid centrioles from sturgeons and salmon]. 138 8

The secretion of epididymal proteins and their binding to spermatozoa in rats were examined after retrograde perfusion of the superior and inferior epididymal arteries with [35S]methionine. PAGE revealed that the pattern of radioactive proteins in the luminal fluid was markedly different from the well-characterized pattern of secretory proteins obtained by in vitro incubation of epididymal minces with labeled methionine. Of the proteins secreted into the lumen, about 1% were associated with Percoll-purified spermatozoa. More proteins were associated with the spermatozoa in the corpus epididymidis than in the caput. Sequential extraction of spermatozoa with an isotonic buffer, a high-salt buffer, Triton X-100, and SDS revealed that almost half of the radiolabeled proteins could be extracted with the isotonic buffer. The firmly bound radioactive proteins remaining, which were extracted with Triton X-100 or SDS, consisted of one major band of 25 kDa and two minor bands of 30 kDa and 32 kDa. Analysis of the sperm-associated proteins at various times after the isotope was administered indicated that tight binding of proteins to spermatozoa occurs within 3 h after isotope injection.
 ...
PMID:Binding of epididymal proteins to rat spermatozoa in vivo. 139 46

Flagella of human spermatozoa were separated from the sperm head by sonication at 25 kHz and subsequent density gradient centrifugation in Percoll. For isolation of the outer dense fibers (ODF), the flagellar membrane and fibrous sheath were dissolved under reducing conditions in the cationic detergent cetyltrimethylammonium bromide (CTAB) for 30, 60 and 90 min, respectively. The isolation steps were monitored by phase-contrast microscopy and electron microscopy. After SDS-PAGE and silver staining two protein bands at 55 and 67 kDa could be detected. An identification of these proteins as phosphoproteins, either with molybdate/methylgreen or rhodamine B, was not possible. The obtained results indicate that the ODF proteins might have more passive elastic than active function with respect to motility of spermatozoa.
 ...
PMID:Isolation and partial characterization of the outer dense fiber proteins from human spermatozoa. 141 83


1 2 3 4 5 6 7 8 9 10 Next >>