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J Moos

Publications and source records attributed to J Moos.

26 records · Page 2Linked to original sources
PubMed1992

Selective expression of a progesterone receptor on the human sperm surface.

OBJECTIVE: To visualize progesterone (P) binding sites on the sperm surface, examine the relationship between hormone binding and hormone action (acrosome reaction), and determine the size of the hormone-responsive sperm subpopulation. DESIGN: Kinetic analysis of P binding was combined with the assessment of the hormone effect using a fluorescent acrosomal marker. SETTING: Private hospital, medical research center, and a university-based andrological laboratory. PATIENTS, PARTICIPANTS: Sperm samples were from healthy volunteers with normal spermiogram values. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Progesterone binding was analyzed by fluorescence microscopy and flow cytometry using P coupled to fluorescein isothiocyanate-labeled bovine serum albumin. Tetramethylrhodamine isothiocyanate-labeled Pisum sativum agglutinin was used as acrosomal marker in double-labeling experiments. RESULTS: After in vitro capacitation, only few spermatozoa (approximately 10%) were able to bind P to the cell surface, but most of these cells subsequently generated the acrosome reaction in response to hormone binding. CONCLUSIONS: The expression of P receptor sites on the human sperm surface is a major factor controlling the P-induced acrosome reaction. Further studies are warranted to explore if defective expression of the receptor can compromise fertility.

Binding Sites↗
PubMed1992

Distinction between true acrosome reaction and degenerative acrosome loss by a one-step staining method using Pisum sativum agglutinin.

When western blots of human sperm proteins solubilized by acid extraction (presumably mainly acrosomal proteins) or by sodium dodecyl sulfate (SDS) were probed with biotin-conjugated Pisum sativum agglutinin (PSA), distinct sets of proteins were labelled in both preparations. When smears of human spermatozoa were treated with methanol either for 30 s or for 15 min and then exposed to FITC-conjugated PSA, the resulting fluorescence pattern essentially depended on the time of methanol treatment. With the longer treatment, fewer spermatozoa showed selective acrosomal labelling and more were labelled uniformly throughout, without a clear predilection for a single sperm region. With the shorter time of methanol treatment, the poorly topographically differentiated, whole-cell labelling was typical of dead spermatozoa as confirmed by a close correlation between the percentages of spermatozoa showing this type of labelling and of those stained supravitally with Hoechst 33258. The preferential whole-cell labelling of dead spermatozoa with PSA is considered to be due to increased availability of the nonacrosomal set of PSA-reactive sites in dead spermatozoa after a short treatment with methanol, whereas this treatment is probably not sufficient to expose most of these sites when applied to living spermatozoa. The simplicity of the staining protocol makes this method feasible in routine work in a number of clinical and research applications.

Acrosome↗
PubMed1991

Mechanism of maturation and nature of carbohydrate chains of boar sperm acrosin.

The acrosin zymogen proacrosin exists in two molecular forms which are believed to be single-chain polypeptides. During autoactivation in a cell-free system, the 55 and 53 kDa zymogens are sequentially converted into the 49, 36, 31 and 25 kDa forms. A similar mechanism of maturation was revealed, when the calcium ionophore A23187 was added to suspensions of boar spermatozoa. The 49 kDa form has been identified as the first active acrosin form in the maturation cascade. However, this form is indistinguishable from the 53 kDa zymogen in SDS-PAGE at nonreducing conditions. Two carbohydrate chains were evidenced on the acrosin molecule. The chain attached to the Asn3 of the acrosin light chain was enzymatically cleaved without loss of acrosin activity. By contrast, the carbohydrate chain linked to the acrosin heavy chain could be cleaved only after acrosin denaturation. Based on the susceptibility of acrosin to endoglycosidases F and H, a biantennary structure of both carbohydrate chains is proposed.

Acrosin↗
PubMed1991

Detection of gelatinolytic enzyme activities after sodium dodecyl sulfate-electrophoresis and protein blotting.

Visualization of proteases with gelatinolytic activity in sodium dodecyl sulfate gels is described. After conventional sodium dodecyl sulfate-polyacrylamide gel electrophoresis, proteins are transferred onto nitrocellulose membranes preincubated with 0.3% gelatine. During the protein electrotransfer, the proteases are renaturated and their enzymatic activity is restored. After nonspecific protein staining, bands with proteolytic activity appear as white areas on a dark background.

Acrosin↗
PubMed1990

Identification of 17-18 kDa zona pellucida binding proteins from boar spermatozoa.

Zona pellucida (ZP) binding proteins from boar spermatozoa were compared with antigens recognized by ACR.2 and ACR.3 monoclonal antibodies. The ZP binding proteins of 55, 53, 45 and 38 kDa are identical with various forms of boar acrosin immunologically detected by ACR.2 antibody. The ZP binding proteins of 17 and 18 kDa are recognized by ACR.3 antibody. The N-terminal amino acid sequence of the 17 kDa protein revealed that it is not derived from an acrosin molecule.

Amino Acid Sequence↗
PubMedDate not supplied

Monoclonal antibodies against boar acrosomal antigens labelling undamaged acrosomes of spermatozoa in immunofluorescence test.

Monoclonal antibodies specific for acrosomal proteins were prepared and characterized. Two of these monoclonal antibodies, ACR.3 and ACR.11, reacted with the same molecular specificity of acrosomal antigens (18-20 kDa), antibody ACR.4 reacted with the 25-27 kDa antigens, and antibody ACR.2 reacted with several forms of boar acrosin (55, 53, 45, and 38 kDa). All monoclonal antibodies labelled the acrosomes of undamaged spermatozoa in immunofluorescence test. This test should be convenient as an immunological test of the sperm quality.

Acrosin↗
PubMedDate not supplied

Monoclonal antibodies to canine intra-acrosomal sperm proteins recognizing acrosomal status during capacitation and acrosome reaction.

Monoclonal antibodies Ds-1 and Ds-2 specifically labelling dog sperm acrosome were prepared by immunization of mice with acetic acid extracts of dog spermatozoa. Electron microscopy and indirect immunofluorescence localized the site of Ds-1 and Ds-2 proteins inside the acrosomal vesicle. Ds-1 antibody detected 55, 76, 115, 120 and 190 kDa proteins under non-reducing conditions, and 73 kDa and 54 kDa proteins after reduction (p73/Ds-1 and p54/Ds-1). 92 kDa and 40 kDa proteins recognized by Ds-2 (p92/Ds-2 and p40/Ds-2) migrated at > 200 kDa in the absence of reducing agent. In vivo, p73/Ds-1 and p54/Ds-1 are therefore likely to be present both in free and complexed form, while all of p92/Ds-2 and p40/Ds-2 form disulfide-bonded complexes. Decrease in the rate of acrosomes stained with Ds-1 and Ds-2 was correlated with the progress of capacitation resulting in the increased rate of spontaneous acrosome reactions, as suggested by a dramatic effect of A23187. Monoclonal antibody to boar acrosin (ACR-2) recognized dog sperm acrosin homologue. A higher rate of ACR-2-negative spermatozoa was observed after capacitation and A23187 treatment compared to Ds-1 and Ds-2, indicating that proteins recognized by Ds-1 and Ds-2 are localized in a specific compartment of acrosome, distinct from acrosin and possibly representing fraction of acrosomal matrix.

Acrosin↗