Sexual dimorphism in antennal receptors of Phyllophaga ravida Blanchard (Coleoptera: Scarabaeoidea: Melolonthidae)

The external morphology of sensilla on the antennae of males and females of Phyllophaga ravida Blanchard is described using scanning electron microscopy. Sexual dimorphism in body and antennal dimensions and in antennal receptor types was found. The female's body is slightly larger than the male's, although male antennal lamellae are longer than in females. Sixteen types of sensilla were identified on the proximal and distal surfaces of lamellae from both sexes, most of them in males: three types of placodea sensilla, four types of auricilica sensilla, five types of basiconica sensilla, and four types of coeloconica sensilla. Also, two types of mechanoreceptor sensilla were present on the lamellae periphery. Furthermore, males had larger placodea, auricilica and some types of basiconica sensilla.     

Differences in boar sperm head shape and dimensions recorded by computer-assisted sperm morphometry are not related to chromatin integrity

Although sperm head shape and relative dimensions are considered reliable indicators of sperm quality, their quantification is most often operator-driven, e.g., subjective. Artificial insemination semen doses from 35 mature stud boars of known fertility and belonging to three breeds and two hybrid breeds (Duroc, Large White, Landrace, respectively, Yorker and Risco) were used in this study. Sperm samples were extended to 100x10(6) cells per mL and 10microL of the sperm suspension used to made smears which, stained, were examined using phase contrast microscopy interfaced with an automated sperm morphology analyzer (ASMA, ISAS). Each sperm head was measured for four primary parameters [area (A) microm(2), perimeter (P) mum, length (L) microm, width (W) microm], and four derived parameters of head shape [(L/W), (4piA/P(2)), ((L-W)/(L+W)), (piLW/4A)]. Definition of head size was statistically performed. The threshold for each class was established on the basis of the area values, considering the 25th percentile as small and the 75th percentile as large spermatozoa. In a second step, sperm head shape was determined as normal, elliptic, abnormal (rugose) contour, long or irregular and percentiles set as above to define spermatozoa with normal values for each shape parameter. Significant differences were found among breeds in the size of morphologically normal spermatozoa, which were significantly larger and more elliptic (P<0.001) in the Duroc breed. Sperm chromatin integrity was studied using the SCSA-assay, with significant differences observed in the degree of fragmentation intensity (DFI) although this value was consistently low in all animals studied. The hereby-validated ASMA was able to determine significant differences in sperm shape and dimensions among breeds, which were not accompanied by deviations in chromatin structure neither within nor between fertile AI-boars.     

Use of proteomics for the identification of novel drug targets in brain diseases

In spite of the rapid advances in the development of the new proteomic technologies, there are, to date, relatively fewer studies aiming to explore the neuronal proteome. One of the reasons is the complexity of the brain, which presents high cellular heterogeneity and a unique subcellular compartmentalization. Therefore, tissue fractionation of the brain to enrich proteins of interest will reduce the complexity of the proteomics approach leading to the production of manageable and meaningful results. In this review, general considerations and strategies of proteomics, the advantages and challenges to exploring the neuronal proteome are described and summarized. In addition, this article presents an overview of recent advances of proteomic technologies and shows that proteomics can serve as a valuable tool to globally explore the changes in brain proteome during various disease states. Understanding the molecular basis of brain function will be extremely useful in identifying novel targets for the treatment of brain diseases.     

Adrenomedullin and its receptor components in adipose tissues: Differences between white and brown fats and the effects of adrenergic stimulation

Male Sprague-Dawley rats were subcutaneously injected with 2.5mg/kg phenylephrine or 2.5mg/kg isoproterenol or both (2.5mg/kg for each drug) for 4 days, twice a day. Samples of scapular brown adipose tissue (BAT) and epididymal white adipose tissue (WAT) were collected for the measurement of adrenomedullin (AM) levels and the gene expression of preproAM, calcitonin receptor like receptor (CRLR) and its activity modifying proteins (RAMPs) by radioimmunoassay and RT-PCR. These values were compared with those in the rats that received 0.9% saline. The gene expression of AM and AM receptor components in BAT are much less than that in epididymal WAT. In BAT there were an increase in AM peptide level after a combined treatment of alpha(1) and beta adrenoceptor agonists and increases in preproAM mRNA levels for rats treated with alpha(1) and beta receptor agonists alone or in combination. Both CRLR and RAMP2 mRNA levels of alphabeta group were increased significantly. In WAT, AM peptide level, RAMP1 and RAMP2 mRNA expression levels were augmented in the alpha group while CRLR mRNA level was enhanced in the beta group. The levels of AM, its receptor and RAMPs are much less in BAT than in WAT but adrenergic stimulation has a greater effect on the AM and its receptor components in BAT than those in WAT. AM stimulates lipolysis and increases the level of uncoupling protein-1 (UCP-1) in BAT. It may therefore enhance thermogenesis by increasing the availability of free fatty acids substrate as well as the UCP-1 level on the mitochondrial membrane.     

The nuclear RhoA exchange factor Net1 interacts with proteins of the Dlg family, affects their localization, and influences their tumor suppressor activity

Net1 is a RhoA-specific guanine nucleotide exchange factor which localizes to the nucleus at steady state. A deletion in its N terminus redistributes the protein to the cytosol, where it activates RhoA and can promote transformation. Net1 contains a PDZ-binding motif at the C terminus which is essential for its transformation properties. Here, we found that Net1 interacts through its PDZ-binding motif with tumor suppressor proteins of the Dlg family, including Dlg1/SAP97, SAP102, and PSD95. The interaction between Net1 and its PDZ partners promotes the translocation of the PDZ proteins to nuclear subdomains associated with PML bodies. Interestingly, the oncogenic mutant of Net1 is unable to shuttle the PDZ proteins to the nucleus, although these proteins still associate as clusters in the cytosol. Our results suggest that the ability of oncogenic Net1 to transform cells may be in part related to its ability to sequester tumor suppressor proteins like Dlg1 in the cytosol, thereby interfering with their normal cellular function. In agreement with this, the transformation potential of oncogenic Net1 is reduced when it is coexpressed with Dlg1 or SAP102. Together, our results suggest that the interaction between Net1 and Dlg1 may contribute to the mechanism of Net1-mediated transformation.     

Differential Gene Expression in a Marine Sponge in Relation to Its Symbiotic State

The molecular mechanisms involved in the establishment and maintenance of sponge photosymbiosis, and in particular the association with cyanobacteria, are unknown. In the present study we analyzed gene expression in a common Mediterranean sponge (Petrosia ficiformis) in relation to its symbiotic (with cyanobacteria) or aposymbiotic status. A screening approach was applied to identify genes expressed differentially in symbiotic specimens growing in the light and aposymbiotic specimens growing in a dark cave at a short distance from the illuminated specimens. Out of the various differentially expressed sequences, we isolated two novel genes (here named PfSym1 and PfSym2) that were up-regulated when cyanobacterial symbionts were harbored inside the sponge cells. The sequence of one of these genes (PfSym2) was found to contain a conserved domain: the scavenger receptor cysteine rich (SRCR) domain. This is the first report on the expression of sponge genes in relation to symbiosis and, according to the presence of an SRCR domain, we suggest possible functions for one of the genes found in the sponge-cyanobacteria symbiosis.     

Complexity, connectivity, and duplicability as barriers to lateral gene transfer

Background

Lateral gene transfer is a major force in microbial evolution and a great source of genetic innovation in prokaryotes. Protein complexity has been claimed to be a barrier for gene transfer, due to either the inability of a new gene's encoded protein to become a subunit of an existing complex (lack of positive selection), or from a harmful effect exerted by the newcomer on native protein assemblages (negative selection).

Results

We tested these scenarios using data from the model prokaryote Escherichia coli. Surprisingly, the data did not support an inverse link between membership in protein complexes and gene transfer. As the complexity hypothesis, in its strictest sense, seemed valid only to essential complexes, we broadened its scope to include connectivity in general. Transferred genes are found to be less involved in protein-protein interactions, outside stable complexes, and this is especially true for genes recently transferred to the E. coli genome. Thus, subsequent to transfer, new genes probably integrate slowly into existing protein-interaction networks. We show that a low duplicability of a gene is linked to a lower chance of being horizontally transferred. Notably, many essential genes in E. coli are conserved as singletons across multiple related genomes, have high connectivity and a highly vertical phylogenetic signal.

Conclusion

High complexity and connectivity generally do not impede gene transfer. However, essential genes that exhibit low duplicability and high connectivity do exhibit mostly vertical descent.     

Self-eating and self-killing: crosstalk between autophagy and apoptosis

The functional relationship between apoptosis ('self-killing') and autophagy ('self-eating') is complex in the sense that, under certain circumstances, autophagy constitutes a stress adaptation that avoids cell death (and suppresses apoptosis), whereas in other cellular settings, it constitutes an alternative cell-death pathway. Autophagy and apoptosis may be triggered by common upstream signals, and sometimes this results in combined autophagy and apoptosis; in other instances, the cell switches between the two responses in a mutually exclusive manner. On a molecular level, this means that the apoptotic and autophagic response machineries share common pathways that either link or polarize the cellular responses.