Differentially methylated genes and androgen receptor re-expression in small cell prostate carcinomas

Small cell prostate carcinoma (SCPC) morphology is rare at initial diagnosis but often emerges during prostate cancer progression and portends a dismal prognosis. It does not express androgen receptor (AR) or respond to hormonal therapies. Clinically applicable markers for its early detection and treatment with effective chemotherapy are needed. Our studies in patient tumor–derived xenografts (PDX) revealed that AR–negative SCPC (AR^?SCPC) expresses neural development genes instead of the prostate luminal epithelial genes characteristic of AR–positive castration-resistant adenocarcinomas (AR⁺ADENO). We hypothesized that the differences in cellular lineage programs are reflected in distinct epigenetic profiles. To address this hypothesis, we compared the DNA methylation profiles of AR^? and AR⁺ PDX using methylated CpG island amplification and microarray (MCAM) analysis and identified a set of differentially methylated promoters, validated in PDX and corresponding donor patient samples. We used the Illumina 450K platform to examine additional regions of the genome and the correlation between the DNA methylation profiles of the PDX and their corresponding patient tumors. Struck by the low frequency of AR promoter methylation in the AR^?SCPC, we investigated this region's specific histone modification patterns by chromatin immunoprecipitation. We found that the AR promoter was enriched in silencing histone modifications (H3K27me3 and H3K9me2) and that EZH2 inhibition with 3-deazaneplanocin A (DZNep) resulted in AR expression and growth inhibition in AR^?SCPC cell lines. We conclude that the epigenome of AR^? is distinct from that of AR⁺ castration-resistant prostate carcinomas, and that the AR^? phenotype can be reversed with epigenetic drugs.     

Optimization of polyphenol extraction from red grape pomace using aqueous glycerol/tartaric acid mixtures and response surface methodology

Grape pomace is a food industry waste containing a high burden of antioxidant polyphenols and several methodologies have been developed for their efficient extraction. However, a sustainable and environmentally friendly process should involve recovery means composed of benign, non-toxic solvents, such as tartaric acid and glycerol, which are natural food constituents. In this line, this study examined the extraction of polyphenols using aqueous tartaric acid/glycerol solutions. The aim was to assess the role of acid and glycerol concentration in the extraction yield, employing a Box-Behnken experimental design and response surface methodology. The results showed that solutions containing only glycerol (20%, w/v) are more suitable for retrieving polyphenols, flavonoids, and pigments from grape pomace, while tartaric acid exerted a negative effect in this regard, when tested at concentrations up to 2% (w/v).     

Structural studies with weak oxytocin antagonists

Summary [Aib³,Thr⁵]OT, [Aib³,Thr(OMe)⁵]OT, [Aib³,Orn⁸]OT, [Thr(OMe)⁵,Orn⁸]OT and [Phe²,Thr(OMe)⁵,Orn⁸]OT were synthesized by solid-phase techniques. From the biological properties of these peptides, it seems that the simultaneous replacement of positions 3 and 5 of oxytocin with Aib and Thr(OMe) results in an analogue devoid of antagonistic activity in comparison with the singly substituted compounds. Simultaneous Orn⁸ substitution does the same in the case of the Aib³ analogue and even leads to agonistic activity in the case of the Thr(OMe)⁵ analogue. Replacement of Tyr² by Phe², e.g. [Phe²,Thr(OMe)⁵,Orn⁸]OT, again favors the appearance of minor antagonistic potency.     

Cytokines and male infertility

Many male infertility cases have no apparent cause, being characterized as idiopathic. Both inflammation and obesity have long been associated with infertility. On one hand, inflammation, such as orchitis and male accessory gland infections (MAGIs), are regulated by inflammatory cytokines. The latter are also produced in the testis by Leydig and Sertoli cells, being associated with gap junctional communication at the blood–testis barrier. Furthermore, they regulate spermatogenesis through cell interaction, Toll-like receptors and production of reactive oxygen species. Additionally, they affect testosterone production, acting at many levels of the pituitary - gonadal axis. Any imbalance in their production may result in infertility. On the other hand, obesity has also been associated with infertility. Adipokines, cytokines produced by white adipose tissue, regulate the lipid and glucose metabolism and the inflammatory system. Recent data on leptin show that it regulates reproduction by adjusting hypothalamus - pituitary - gonadal axis at both the central and peripheral levels. In this regard, resistin, visfatin and the GH secretagogue peptic hormone ghrelin affect spermatogenesis, whereas data on adiponectin are rather scarce. In conclusion, inflammatory cytokines and adipokines seem to have a pivotal role in the regulation of spermatogenesis; any imbalance in this stable environment may lead to infertility. Nevertheless, further studies are needed to clarify their exact role.     

Dogfish egg case structural studies by ATR FT-IR and FT-Raman spectroscopy

The dogfish egg case is a composite structure that combines mechanical tensile strength, toughness and elasticity with high permeability to small molecules and ions. Presumably, it provides both a protective and a filtering role for the egg/embryo contained within it. In this work, we performed structural studies of the Galeus melastomus egg case at two different stages of the hardening process, utilizing ATR FT-IR and FT-Raman spectroscopy. Based on these data we deduce that: (a) The G. melastomus egg case, in close analogy to that of the related species Scyliorhinus cunicula, is a complex, composite structure which consists mainly of an analogue of collagen IV. This network forming protein appears to have common secondary structural characteristics in the entire egg case. (b) The outermost layer of the non-sclerotized egg case is especially rich in tyrosine, while the innermost layer is rich in polysaccharides, presumably glycosaminoglycans, and lipids. These differences are diminished upon hardening. (c) Disulfide bonds do not appear to play a significant role in cross-linking. However, cross-links involving tyrosine residues appear to sclerotize the egg case. It is proposed that the intensity of the Raman band at ca. 1615 cm(-1), which is due to ring stretching vibrations of Tyr, might be a useful indicator of the sclerotization status of a certain proteinaceous tissue, when tyrosines are involved in sclerotization mechanisms.     

Classification and gradient analysis of the beech forest vegetation of the southern Rodopi (northeast Greece)

Pure and mixed beech forest vegetation of the southern Rodopi range (northeast Greece) was studied using 614 relevés and multivariate analyses (TWINSPAN and DCA). Classification of the relevés resulted in 12 vegetation units, 8 of which were ranked as associations or communities and the rest as subcommunities and variants. DCA diagrams of relevés and taxa indicated that floristic differentiation was attributed mainly to factors such as altitude (affecting temperature and humidity), soil nutrient content and substrate type (affecting physical and chemical soil properties). Differential taxa of vegetation units were chosen based on their phi coefficient values, which were calculated from three different percentage synoptic tables that corresponded to three ranks (ecological groups, associations and communities, and subcommunities and variants) of floristic differentiation. The calculation of phi coefficient on the basis of relative constancy of taxa helps to overcome the problem of the dependence of fidelity values on the number of relevés per vegetation unit and to facilitate the better investigation of the floristic differentiation even of rare vegetation units represented by a small number of relevés. Furthermore, the calculation of fidelity values for different hierarchical levels enables a more detailed and thorough investigation of the floristic differentiation of the vegetation units.     

Pleurotus opuntiae revisited – An insight to the phylogeny of dimitic Pleurotus species with emphasis on the P. djamor complex

The name Pleurotus opuntiae is indiscriminately used for describing mushrooms with white to off-white to white-grey pilei with short or absent stipe and dimitic hyphal system, which grow on plants of the genera Opuntia, Yucca, Agave, Phytolacca etc. However, the outcome of the present study evidences that this name should be reserved for specimens deriving from the Mediterranean area only; an epitype originating from Italy on Opuntia ficus-indica is designated. Pertinent material was sequenced by using the internal transcribed spacer region (ITS) and found to be phylogenetically related to P. djamor from Kenya and Nigeria, while members of the P. djamor complex from other continents were clearly more distant. Results were further corroborated by examining the large subunit of nuclear ribosomal DNA (LSU) and the second subunit of RNA polymerase II (RPB2). The P. djamor complex shows high intraspecific polymorphism evidenced by sequence divergence and genetic distance values, presents a cosmopolitan distribution and also comprises material initially identified as P. flabellatus, P. opuntiae, P. ostreatoroseus, P. parsonsiae and P. salmoneostramineus. An ITS tree including representative specimens from all major Pleurotus species is provided for the first time and ambiguous taxa are discussed in the context of new findings.