Expression of Tas1 Taste Receptors in Mammalian Spermatozoa: Functional Role of Tas1r1 in Regulating Basal Ca2+ and cAMP Concentrations in Spermatozoa

Background: During their transit through the female genital tract, sperm have to recognize and discriminate numerous chemical compounds. However, our current knowledge of the molecular identity of appropriate chemosensory receptor proteins in sperm is still rudimentary. Considering that members of the Tas1r family of taste receptors are able to discriminate between a broad diversity of hydrophilic chemosensory substances, the expression of taste receptors in mammalian spermatozoa was examined. Methodology/Principal Findings: The present manuscript documents that Tas1r1 and Tas1r3, which form the functional receptor for monosodium glutamate (umami) in taste buds on the tongue, are expressed in murine and human spermatozoa, where their localization is restricted to distinct segments of the flagellum and the acrosomal cap of the sperm head. Employing a Tas1r1-deficient mCherry reporter mouse strain, we found that Tas1r1 gene deletion resulted in spermatogenic abnormalities. In addition, a significant increase in spontaneous acrosomal reaction was observed in Tas1r1 null mutant sperm whereas acrosomal secretion triggered by isolated zona pellucida or the Ca2+ ionophore A23187 was not different from wild-type spermatozoa. Remarkably, cytosolic Ca2+ levels in freshly isolated Tas1r1-deficient sperm were significantly higher compared to wild-type cells. Moreover, a significantly higher basal cAMP concentration was detected in freshly isolated Tas1r1-deficient epididymal spermatozoa, whereas upon inhibition of phosphodiesterase or sperm capacitation, the amount of cAMP was not different between both genotypes. Conclusions/Significance: Since Ca2+ and cAMP control fundamental processes during the sequential process of fertilization, we propose that the identified taste receptors and coupled signaling cascades keep sperm in a chronically quiescent state until they arrive in the vicinity of the egg - either by constitutive receptor activity and/or by tonic receptor activation by gradients of diverse chemical compounds in different compartments of the female reproductive tract

Functionalization of polyurethane dispersions for controlled interactions with different substrates

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Antigenic diversity in Haemophilus ducreyi as shown by western blot (immunoblot) analysis.

The antigenic diversity within a panel of 63 Haemophilus ducreyi isolates was examined by Western blot (immunoblot) analysis with a pool of 238 well-characterized human antisera. When a serum pool adsorbed on a mixture of Haemophilus influenzae, H. parainfluenzae, and H. parahaemolyticus was used, the immunoprofiles suggested that prominent antigenic proteins involved in the human immune response have apparent molecular masses of 63, 42, 34 to 30, and 28.5 to 28 kDa. Preliminary subcellular localization revealed that these antigens are associated with the cellular membrane. Two subsets of antigens were discriminated by detergent extraction. There was no evidence that the antigen composition is altered by changing the growth conditions. With a serum pool adsorbed on the Haemophilus spp. mixture supplemented with Actinobacillus actinomycetemcomitans, Pasteurella ureae, Neisseria gonorrhoeae, and Escherichia coli, antigenic determinants more specific for H. ducreyi were identified. An immunodominant 28.5- to 28-kDa protein was expressed by all H. ducreyi isolates. In the range from 34 to 30 kDa, 56 isolates revealed a dominant protein with variable molecular mass. By using both proteins (28.5 to 28 kDa and 34 to 30 kDa) as immunotypic markers, seven different immunopatterns were identified. Antigenic diversity among isolates from different geographical origins as well as from a single area was observed

Exploiting keywords life-cycle to analyse the dynamics of an emerging field : An experiment in Nanosciences with the Kwords lab

Synthèse de l'intervention consultable sur internet : http://www.enid-europe.org/conference/abstracts/Baneyx-Delemarle-etal_ENID.pd

Concomitant constitutive LNK and NFE2 mutation with loss of sum9oylation in a case of hereditary thrombocythemia

The vast majority of patients with myeloproliferative neoplasms (MPN), polycythemia vera, essential thrombocythemia (ET), and primary myelofibrosis, acquire driver mutations in the JAK2, MPL or CALR gene. Clustering of MPN is seen in select families, but in most pedigrees the MPN-predisposing change has not been determined and affected individuals somatically acquire one of the three above mentioned driver mutations. In contrast, a small number of individuals with hereditary thrombocythemia (HT) carry constitutive alterations, for example in the TPO or the LNK (SH2B3) gene.1–4 Acquired mutations in LNK, a negative regulator of JAK2 signaling, rarely occur in both sporadic and familial MPN cases.1,2 In the latter, they do not segregate with disease phenotype and diseased individuals acquire a concomitant MPN driver mutation.2 It, therefore, appears unlikely that mutant LNK acts as a driver in MPN

Profil et besoins des principaux aidants informels de patients âgés dans les hôpitaux gériatriques de jour belges: une étude transversale multicentrique

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