Selective inhibition of prostaglandin biosynthesis by gold salts and phenylbutazone

Gold salts and phenylbutazone selectively inhibit the synthesis of PGF_2α and PGE₂ respectively. Lowered production of one prostaglandin species is accompanied by an increased production of the other. Selective inhibition by these drugs was observed in the presence of adrenaline, reduced glutathione and copper sulphate under conditions when most anti-inflammatory compounds inhibited PGE₂ and PGF_2α syntheses equally. It is postulated that selective inhibitors may have a different mode of action and beneficial effects may be related to the endogenous ratio of PGE to PGF required for normal function.     

Effects of chemical pollutants on reproductive and developmental processes in Italian amphibians

It is a widely held belief that environmental contaminants contribute to the decline of amphibian populations. By spending most of their early life in water and later stages on the land, amphibians face a constant risk of exposure to pesticides and other chemical pollutants in both aquatic and terrestrial environments. This review presents an overview of the studies carried out in Italian amphibians to highlight hazardous effects of bioaccumulation of chemical pollutants in juveniles and adults in various contaminated environments. Further, the studies in the laboratory setting assessing the effects of chemical pollutants on reproductive and developmental processes are reported. These studies and their relative references have been summarized in a tabular form. Three prominent contaminant groups were identified: herbicides, insecticides, and fungicides; and only a few works reported the effects of other chemical pollutants. Each pollutant group has been delegated to a section. All through the literature survey, it is seen that interest in this topic in Italy is very recent and sparse, where only a few anuran and caudata species and only some chemical pollutants have been studied.     

AMPA receptor expression in mouse testis and spermatogonial GC-1 cells: A study on its regulation by excitatory amino acids

Excitatory amino acids (EAAs) are found present in the nervous and reproductive systems of animals. Numerous studies have demonstrated a regulatory role for Glutamate (Glu), d -aspartate ( d -Asp) and N-methyl- d -aspartate (NMDA) in the control of spermatogenesis. EAAs are able to stimulate the Glutamate receptors, including the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR). Here in, we assess expression of the main AMPAR subunits, GluA1 and GluA2/3, in the mouse testis and in spermatogonial GC-1 cells. The results showed that both GluA1 and GluA2/3 were localized in mouse testis prevalently in spermatogonia. The subunit GluA2/3 was more highly expressed compared with GluA1 in both the testis and the GC-1 cells. Subsequently, GC-1 cells were incubated with medium containing l -Glu, d -Glu, d -Asp or NMDA to determine GluA1 and GluA2/3 expressions. At 30 minutes and 2 hours of incubation, EAA-treated GC-1 cells showed significantly higher expression levels of both GluA1 and GluA2/3. Furthermore, p-extracellular signal-regulated kinase (ERK), p-Akt, proliferating cell nuclear antigen (PCNA), and Aurora B expressions were assayed in l -Glu-, d -Glu-, and NMDA-treated GC-1 cells. At 30 minutes and 2 hours of incubation, treated GC-1 cells showed significantly higher expression levels of p-ERK and p-Akt. A consequent increase of PCNA and Aurora B expressions was induced by l -Glu and NMDA, but not by d -Glu. Our study demonstrates a direct effect of the EAAs on spermatogonial activity. In addition, the increased protein expression levels of GluA1 and GluA2/3 in EAA-treated GC-1 cells suggest that EAAs could activate ERK and Akt pathways through the AMPAR. Finally, the increased PCNA and Aurora B levels may imply an enhanced proliferative activity.     

Estrogen receptor beta localization in the lizard (Podarcis s. sicula) testis

There is increasing evidence that 17beta-estradiol is necessary for normal male fertility. The aim of the present study was to characterize estrogen receptor beta (ERbeta) expression in a non-mammalian vertebrate model, the lizard (Podarcis s. sicula) testis. Immunocytochemical analysis shows that ERbeta proteins are present among germ cells in the nucleus of the spermatogonia, in primary spermatocytes and spermatids. Western blot analysis with antibodies against the ERbeta gene product revealed an isoform with a specific weight of 55 kDa. In conclusion, the widespread expression of ERbeta in the Podarcis s. sicula testis is consistent with a role for estrogens in modulating spermatogenesis in the male.     

Prolin-rich tyrosine kinase 2 (PYK2) expression and localization in mouse testis

Prolin-rich kinase 2 (PYK2) is a nonreceptor tyrosine kinase related to the focal adhesion kinase (FAK) p125(FAK). PYK2 is rapidly phosphorylated on tyrosine residues in response to various stimuli, such as tumor necrosis factor-alpha (TNF-alpha), changes in osmolarity, elevation in intracellular calcium concentration, angiotensin, and UV irradiation. PYK2 has ligand sequences for Src homology 2 and 3 (SH-2 and SH-3), and has binding sites for paxillin and p130(cas). Activation of PYK2 leads to modulation of ion channel function, phosphorylation of tyrosine residues, and activation of the MAP kinase signaling pathways. Immunocytochemistry shows that PYK2 is present in mouse germinal and Sertoli cells (ser). Northern blot and immunoprecipitation analysis demonstrate that, among germinal cells, PYK2 is more abundant in spermatocytes (spc) and spermatids (spt); in addition, immunofluorescence analysis clearly shows that the diffuse cytoplasmic localization of PYK2 changes in a specific cellular compartment in spt and spermatozoa.     

Coinfection by Strongyloides stercoralis in blood donors infected with human T-cell leukemia/lymphoma virus type 1 in São Paulo City, Brazil

The frequency of coinfection with Strongyloides stercoralis and human T-cell leukemia/lymphoma virus type 1 (HTML-1) was determined in 91 blood donors examined at the blood bank of a large hospital in S?o Paulo city, Brazil. As control group 61 individuals, not infected by HTLV-1, were submitted to the same techniques for the diagnosis of S. stercoralis infection. In HTLV-1 infected patients the frequency of S. stercoralis infection was 12.1%; on the other hand, the control group showed a frequency significantly lower of S. stercoralis infection (1.6%), suggesting that HTLV-1 patients should be considered as a high risk group for strongyloidiasis in S?o Paulo city.     

Radiation of the Tnt1 retrotransposon superfamily in three Solanaceae genera

Background  

Tnt1 was the first active plant retrotransposon identified in tobacco after nitrate reductase gene disruption. The Tnt1 superfamily comprises elements from Nicotiana (Tnt1 and Tto1) and Lycopersicon (Retrolyc1 and Tlc1) species. The study presented here was conducted to characterise Tnt1-related sequences in 20 wild species of Solanum and five cultivars of Solanum tuberosum.     

Molecular pathways involved in the cyclic activity of frog (Pelophylax esculentus) Harderian gland: Influence of temperature and testosterone

The Harderian gland of Pelophylax esculentus (previously: Rana esculenta) shows seasonal secretory activity changes. Specifically, the secretory activity reaches a maximum during the hottest months, i.e., July and August, drops in September and slowly increases from October onwards. Expressions of P-CaMKII, P-ERK1 and P-Akt1 correlate well with gland secretory activity; i.e., they peak immediately before the hottest part of the year (maximum secretory activity). When the gland activity declines, kinase expressions drop and remain low until February. Experiments of thermal manipulation indicate that high temperature induces the activation of CaMKII, ERK1 and Akt1, and at low temperatures, Akt1 expression decreases. Experiments of chemical castration indicate that the Harderian gland of Cyproterone acetate-treated frogs shows lower Akt1 activity as compared to controls, but the CaMKII and ERK1 activities remain unchanged. Furthermore, in a period of resumed gland activity (October–December) we observed the highest expression of PCNA, a mitotic marker. Immediately after the proliferative phase, we found the highest expression of caspase 3, an enzyme that plays a key role in apoptosis. In combination, the results suggest the following: 1) CaMKII, ERK1, and Akt1 modulate the annual secretory activity of the frog Harderian gland; 2) CaMKII and ERK1 activities are regulated by temperature, whereas both temperature and testosterone likely play a central role in Akt1 regulation; and 3) proliferation and apoptosis occur to restore and balance, respectively, an adequate cell number, which is essential to gland function.