Pyrazole derived from (+)-3-carene; a novel potent,selective scaffold for sphingosine-1-phosphate (S1P1) receptor agonists

High throughput screening and hit to lead optimization led to the identification of ‘carene’ as a promising scaffold showing selective S1P₁ receptor agonism. In parallel to this work we have established a pharmacophore model for the S1P₁ receptor highlighting the minimal structural requirement necessary for potent receptor agonism.     

Cellular and extracellular behavior in the gerbil (Meriones unguiculatus) ventral prostate following different types of castration and the consequences of testosterone replacement

Mongolian gerbils (Meriones unguiculatus) were grouped into two experimental groups: GEx.01 suffered orchiectomy and after 30 days received doses of testosterone cipionate (T), while GEx.02 received weekly and alternated doses of the anti-androgens cyproterone acetate and flutamide for 30 days, and the animals were then euthanized. Structural evaluation reveals a more intense reduction in epithelial height in GEx.02. Smooth muscle cells (SMC) presented a star-shaped aspect after 30 days of hormonal ablation and basal membrane was shown to be more intensely grooved in GEx.01. In both groups, after hormonal replacement, recovery in epithelial height could be noted and the SMC presented its phenotypes, but an increase in RER was seen, characterizing a modulation from its contractile to secreting phenotype. In conclusion, the prostate presented involution capacity after androgen ablation and the ability to reorganize after hormonal replacement, but events resulting from orchiectomy and subsequent T replacement were shown to be more aggressive to the prostate.     

An overview of malaria transmission from the perspective of Amazon Anopheles vectors

In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence.     

Tissue remodeling in Guinea pig lateral prostate at different ages after estradiol treatment

Estrogen seems to have an essential role in the fibromuscular growth characteristic of benign prostatic hyperplasia (BPH). This paper describes the effects of chronic estradiol treatment on Guinea pig prostatic stroma at different ages. Tissues from experimental animals were studied by histological and histochemical procedures, morphometric-stereological analysis and transmission electron microscopy (TEM). Marked fibromuscular hypertrophy was observed after estradiol treatment in animals of pre-pubertal and adult ages. Increases in the density and thickness of the collagen and elastic fibers were observed by histochemistry. TEM revealed wide distributions of collagen fibrils and large elastic fibers adjacent to the epithelial basal lamina and between the stromal cells, establishing contacts between them. These results indicate that the Guinea pig prostate simulates the stromal modifications observed in BPH in some aged animals after estrogen treatment at different ages, making it a good model for this disease.     

Introgression in natural populations of bioindicators: a case study of Carabus splendens and Carabus punctatoauratus

The evolutionary importance of hybridization in wild plants and animals has become increasingly widely recognized in the last decade. In practical terms, hybridization provides an exceptionally tough set of problems for conservation biologists. We illustrate this in a case study of two Carabidae species widely used to evaluate the impact of human activities on biodiversity. These two species live in a complex mosaic of sympatry/allopatry and are known to hybridize in controlled conditions. Hybridization has not been quantified in natural populations to date due to the lack of a simple set of phenotypic traits for identifying hybrids. We thus screened for hybrids in natural populations, by multilocus genotyping at nine microsatellite loci. A high level of genetic differentiation between these two taxa was observed, as shown by allelic frequency distributions. Two Bayesian assignment procedures without obligatory pure taxon references were used to infer different classes of hybrids (F(1), F(2) and backcrosses) and mixture proportions between the two species. A low level of hybridization (F(1) genotypes) was observed in natural populations, contrasting with results obtained in controlled conditions. A high level of introgression was, however, detected at three of 12 sites, as revealed by the detection of backcrossed genotypes. This interspecific gene flow was detected in a limited zone of the common geographical range of the two species and was not related to the pattern of sympatry/allopatry. We then considered the origin and repercussions of this introgression, based on intraspecific genetic diversity and geographical structure.     

Evidence for the sucrose-binding protein role in carbohydrate metabolism and transport at early developmental stage

Despite the large amount of data regarding sucrose-binding proteins (SBP), their functions remain largely unknown and controversial. In this investigation we performed a detailed temporal and spatial characterization of the phenotypes related to photosynthesis, sucrose exudation and carbohydrate metabolism in SBP antisense plants to gain insights into the physiological role of SBP. Significant reductions in net photosynthesis and in stomatal conductance were observed in the SBP antisense lines but were restricted to the vegetative phase, and persisted during a daily time course at this phase. Photosynthesis was saturated at a substantially lower irradiance in source leaves of the antisense lines, suggesting that light utilization is decreased in these plants. A slight reduction in soluble sugars was observed throughout the development of source leaves, partially overlapping a decrease in sucrose synthase activity (EC 2.4.1.13); whereas a transient increase in starch and adinosine diphosphate (ADP)-glucose pyrophosphorylase activity (EC 2.7.7.27) as well as decreased leaf sucrose exudation were detected in the beginning of the vegetative phase. These changes in source leaves were accompanied by reductions in sucrose and starch in sink leaves, hexoses and sucrose in roots and hexoses in shoot apex, which were observed before the occurrence of a significant reduction in height and in leaf number in the transgenic lines. These alterations in growth parameters did not persist throughout the development, but were associated with a delay in flowering time and leaf senescence in the SBP antisense lines. A likely involvement of SBP in sink strength is discussed.     

Testosterone stimulates growth and secretory activity of the female prostate in the adult gerbil (Meriones unguiculatus)

The prostate of the female gerbil (Meriones unguiculatus) is similar to the human female prostate (Skene gland) and, despite its reduced size, it is functional and shows secretory activity. However, virtually nothing is known about its physiological regulation. This study was thus undertaken to evaluate the behavior of the gerbil female prostate in a hyperandrogenic condition. Adult females received subcutaneous injections of testosterone cypionate (1 mg/kg body weight every 48 h) up to 21 days. Circulating levels of testosterone and estradiol were monitored, and the prostate and ovaries subjected to structural and immunocytochemical analyses. The treatment resulted in sustained high levels of circulating testosterone, and caused a transient increase in estradiol. There was an increase in epithelial cell proliferation accompanied by significant reorganization of the epithelium and an apparent reduction in secretory activity, followed by a progressive increase in luminal volume density and accumulation of secretory products. Immunocytochemistry identified the expression of androgen receptor and a prostate-specific antigen (PSA)-related antigen in prostatic epithelial cells. A circulating PSA-related antigen was also found, and its concentration showed strong negative correlation with circulating estrogen. Epithelial dysplasia was detected in the prostate of treated females. Analysis of the ovaries showed the occurrence of a polycystic condition and stromal cell hyperplasia. The results indicate that testosterone has a stimulatory effect on the female prostate, inducing epithelial cell proliferation, differentiation, secretory activity, and dysplasia. The results also suggest that prostatic growth and activity, polycystic ovaries, and ovarian stromal cell hyperplasia are related to a hyperandrogenic condition in females.     

Oncostatin M suppresses EGF-mediated protein tyrosine phosphorylation in breast cancer cells

The effect of oncostatin M (OM) on epidermal growth factor (EGF)-mediated protein tyrosine phosphorylation in an infiltrating ductal breast carcinoma cell line, H3922, was investigated by Western blot analysis. Pretreatment of H3922 cells with OM for 72 h suppressed EGF-stimulated protein tyrosine phosphorylation signals by 77%. Interestingly, pretreatment with OM for 6 or 48 h had little effect on these signals. EGF-mediated tyrosine phosphorylation of EGF receptor (EGFR) was suppressed by 55% in 72-h OM pretreated H3922 cells. No reduction in EGFR protein expression was detected in these cells. Flow cytometric analysis verified that OM does not suppress EGFR expression. The effect of OM could not be attributed to induction of protein tyrosine phosphatases. An H3922 subclone cell line, designated H3922-8, was found to exhibit no proliferative response to treatment with EGF. However, EGF-mediated protein tyrosine phosphorylation was detected in these cells. Radioligand EGF binding studies comparing H3922 to H3922-8 cells indicated that the clonal cells apparently lack high affinity EGF receptors. The mechanism by which OM suppresses EGF-mediated tyrosine phosphorylation has not been completely characterized. However, the suppressive effect occurs regardless of whether the cells are acutely responsive (H3922) or virtually unresponsive (H3922-8) to EGF stimulation of cell growth.     

Follicle-stimulating hormone accelerates mouse oocyte development in vivo

During folliculogenesis, oocytes grow and acquire developmental competence in a mutually dependent relationship with their adjacent somatic cells. Follicle-stimulating hormone (FSH) plays an essential and well-established role in the differentiation of somatic follicular cells, but its function in the development of the oocyte has still not been elucidated. We report here that oocytes of Fshb(-/-) mice, which cannot produce FSH, grow at the same rate and reach the same size as those of wild-type mice. Consistent with this observation, the granulosa cells of Fshb(-/-) mice express the normal quantity of mRNA encoding Kit ligand, which has been implicated in oocyte growth. Oocytes of Fshb(-/-) mice also accumulate normal quantities of cyclin B1 and CDK1 proteins and mitochondrial DNA. Moreover, they acquire the ability to complete meiotic maturation in vitro and undergo transition from non-surrounded nucleolus to surrounded nucleolus. However, these events of late oocyte development are significantly delayed. Following in vitro maturation and fertilization, only a small number of embryos derived from oocytes of Fshb(-/-) mice reach the blastocyst stage. Administration of equine chorionic gonadotropin, which provides FSH activity, 48 h before in vitro maturation increases the number of blastocysts obtained subsequently. These results indicate that FSH is not absolutely required for oocyte development in vivo but that this process occurs more rapidly in its presence. We suggest that FSH may coordinate the development of the germline and somatic compartments of the follicle, ensuring that ovulation releases a developmentally competent egg.     

Physiological responses to salt stress in young umbu plants

Soil salinity affects plant growth and development due to harmful ion effects and water stress caused by reduced osmotic potential in the soil solution. In order to evaluate the effects of salt stress in young umbu plants, research was performed in green house conditions at the Laboratory of Plant Physiology at Federal Rural University of Pernambuco, Brazil. Growth, stomatal behaviour, water relations, and both inorganic and organic solutes were studied aiming for a better understanding of the responses of umbu plants to increasing salinity. Plants were grown in washed sand with Hoagland and Arnon nutrient solution with 0, 25, 50, 75, and 100 mM NaCl. Growth, leaf water potential, transpiration, and diffusive resistance were evaluated. Na⁺, K⁺, Cl⁻, soluble carbohydrates, and free amino acid contents were measured in several plant organs. Most variables were affected with salinity above 50 mM NaCl showing decreases in: number of leaves, plant height, stems diameter, and dry masses, and increases in root-to-shoot ratio. Reductions in ψ_pd were observed in plants grown under 75 and 100 mM NaCl. All salt levels above zero increased Na⁺ and Cl⁻ contents in leaves. However, K⁺ content was not affected. Na⁺ and Cl⁻ in stems and roots reached saturation in treatments above 50 mM NaCl. Organic solute accumulation in response to salt stress was not observed in umbu plants. These results suggest that umbu plants tolerate salt levels up to 50 mM NaCl without showing significant physio-morphological alterations.