Roles of osmolality, calcium - Potassium antagonist and calcium in activation and flagellar beating pattern of sturgeon sperm

The present study shows the roles of osmolality, calcium (Ca(2+))-potassium (K(+)) antagonist and Ca(2+) in sperm activation and flagellar beating of a sturgeon species, sterlet (Acipenser ruthenus). Sperm motility was activated at hypoosmolality relative to seminal plasma and suppressed at 175 mOsmol kg(-1). Sperm activation was totally suppressed by 0.35mM K(+), but Ca(2+) could fully reverse K(+) inhibitory effect at Ca(2+): K(+) ratio of 0.25. Neither EGTA (a chelator of Ca(2+) ions) nor nifedipine (a Ca(2+) channel blocker) prevented sperm activation. But, sperm motility and velocity were significantly decreased by EGTA, nifedipine and an inhibitor for Ca(2+)/calmodulin activated phosphodiesterase (w-7) that suggest role of Ca(2+) signaling after triggering sperm activation through hypoosmolality. Symmetric flagellar beating was also turned to asymmetric after activation in w-7, which is an evidence for modulation of Ca(2+)-binding proteins activity. Sturgeon sperm, similar to salmonids, is immotile in seminal plasma due to high K(+) concentrations, but the mechanism of sperm activation seems to be closer to other fish species where osmolality prohibits sperm activation in seminal plasma. In these species, hypoosmolality is the primary signal for sperm Ca(2+)-dependent signaling of axonemal beating.     

Calcium ion supplementation increases brook trout Salvelinus fontinalis spermatozoa activation at the end of the spawning season

The role of environmental ion composition and osmolality in calcium ion (Ca²⁺) signalling of spermatozoa activation over the course of the spawning period of brook trout Salvelinus fontinalis was investigated. Motility at the end of spawning was low (mean ± s.d. of 5 ± 2% motile spermatozoa with curvilinear velocity of 25 ± 8 µm s^?1). Addition of 10 mM Ca²⁺ to the activation medium resulted in values similar to those recorded during the middle of the spawning period (mean ± s.d. of 95 ± 6% motile spermatozoa with curvilinear velocity of 130 ± 15 µm s^?1).     

DIRECT AND INDIRECT ESTIMATES OF SEED VERSUS POLLEN MOVEMENT WITHIN A POPULATION OF PONDEROSA PINE

We examined the spatial distribution of maternally inherited mitochondrial DNA and paternally inherited chloroplast DNA polymorphisms in a permanently marked stand of ponderosa pine (Pinus ponderosa Laws). Movement of maternally inherited mtDNA occurs only via seed dispersal, and mtDNA haplotypes showed significant patch structure. Moreover, individuals within patches identified by mtDNA haplotypes were related approximately as half-sibs based upon analysis of allozyme genotypes. Thus, seed dispersal is limited within the population, and creates matrilineal clusters in space. By contrast, paternally inherited cpDNA is dispersed by movement of both seed and pollen. Chloroplast DNA polymorphisms showed no evidence of patch structure, but rather a weak (and nonsignificant) trend toward hyperdispersion, suggesting nearly unlimited movement of pollen among trees within this stand. Two of the trees had unique allozyme alleles, which were used to directly measure pollen movement away from those trees. Marked pollen was as likely to disperse across the population as it was to fertilize near neighbors.     

Large-scale analysis of chromosomal aberrations in cancer karyotypes reveals two distinct paths to aneuploidy

Background  

Chromosomal aneuploidy, that is to say the gain or loss of chromosomes, is the most common abnormality in cancer. While certain aberrations, most commonly translocations, are known to be strongly associated with specific cancers and contribute to their formation, most aberrations appear to be non-specific and arbitrary, and do not have a clear effect. The understanding of chromosomal aneuploidy and its role in tumorigenesis is a fundamental open problem in cancer biology.     

Allergen Microarray Indicates Pooideae Sensitization in Brazilian Grass Pollen Allergic Patients

Background

Grass pollen, in particular from Lolium multiflorum is a major allergen source in temperate climate zones of Southern Brazil. The IgE sensitization profile of Brazilian grass pollen allergic patients to individual allergen molecules has not been analyzed yet.

Objective

To analyze the IgE sensitization profile of a Brazilian grass pollen allergic population using individual allergen molecules.

Methods

We analyzed sera from 78 grass pollen allergic patients for the presence of IgE antibodies specific for 103 purified micro-arrayed natural and recombinant allergens by chip technology. IgE-ELISA inhibition experiments with Lolium multiflorum, Phleum pratense extracts and a recombinant fusion protein consisting of Phl p 1, Phl p 2, Phl p 5 and Phl p 6 were performed to investigate cross-reactivities.

Results

Within the Brazilian grass pollen allergic patients, the most frequently recognized allergens were Phl p 1 (95%), Phl p 5 (82%), Phl p 2 (76%) followed by Phl p 4 (64%), Phl p 6 (45%), Phl p 11 (18%) and Phl p 12 (18%). Most patients were sensitized only to grass pollen allergens but not to allergens from other sources. A high degree of IgE cross-reactivity between Phleum pratense, Lolium multiflorum and the recombinant timothy grass fusion protein was found.

Conclusions

Component-resolved analysis of sera from Brazilian grass pollen allergic patients reveals an IgE recognition profile compatible with a typical Pooideae sensitization. The high degree of cross-reactivity between Phleum pratense and Lolium multiflorum allergens suggests that diagnosis and immunotherapy can be achieved with timothy grass pollen allergens in the studied population.     

Acrosome staining and motility characteristics of sterlet spermatozoa after cryopreservation with use of methanol and DMSO

In this study we describe acrosome staining and motility characteristics of fresh and cryopreserved sterlet (Acipenser ruthenus L.) spermatozoa using soybean trypsin inhibitor-Alexa conjugate fluorescent staining and computer-aided sperm analysis (CASA), respectively. Methanol or dimethylsulfoxide (DMSO) were used as cryoprotectants. After cryopreservation a decline in sperm motility characteristics occurred, but no differential effect between cryoprotectant was observed. Cryopreservation caused a significant increase in the percentage of spermatozoa with acrosome stained by SBTI-Alexa for samples cryopreserved using DMSO compared to methanol. These data suggest that the low usefulness of DMSO for cryopreservation of sturgeon spermatozoa is related to its harmful specific effect towards the acrosome, probably by causing its precocious triggering, much before any egg contact.