Run or Die in the Evolution of New MicroRNAs—Testing the Red Queen Hypothesis on De Novo New Genes

The Red Queen hypothesis depicts evolution as the continual struggle to adapt. According to this hypothesis, new genes, especially those originating from nongenic sequences (i.e., de novo genes), are eliminated unless they evolve continually in adaptation to a changing environment. Here, we analyze two Drosophila de novo miRNAs that are expressed in a testis-specific manner with very high rates of evolution in their DNA sequence. We knocked out these miRNAs in two sibling species and investigated their contributions to different fitness components. We observed that the fitness contributions of miR-975 in Drosophila simulans seem positive, in contrast to its neutral contributions in D. melanogaster, whereas miR-983 appears to have negative contributions in both species, as the fitness of the knockout mutant increases. As predicted by the Red Queen hypothesis, the fitness difference of these de novo miRNAs indicates their different fates.     

Epicuticular wax of Colletia paradoxa

The composition of Colletia paradoxa epicuticular wax was determined. Hydrocarbons (27%), ketones (22%—mainly taraxerone), free acids (17%), free     

Germ cell proliferation and apoptosis during testicular regression in a seasonal breeding fish kept in captivity

Cell proliferation and apoptosis regulate germ cells stock and sperm production, eliminate anomalous gametes, and are essential parameters to consider in fish farming. Herein, spermatogenic activity as well as germ cell proliferation and apoptosis were assessed in Leporinus taeniatus, a seasonal breeding species from the São Francisco River basin, Brazil. Testes of 24 adult fishes from a farming station were sampled between December and July and processed for light and transmission electron microscopy and immunohistochemistry for PCNA and TUNEL assay. The gonadosomatic index and seminiferous tubule diameters presented higher values during the breeding season (December/January and February/March), and then significantly reduced during the regression and resting stages (April/May and June/July). Phagocytosis of spermatozoa by Sertoli cells was evident during gonadal regression, but a significant number (up to 30%) remained at the tubular lumen during the resting stage. A higher PCNA/TUNEL ratio occurred in the breeding period, leading to an elevated proportion (%) of spermatogonia (G_A and G_B) in resting. Moreover, a higher TUNEL/PCNA ratio indicates the contribution of apoptosis to the reduction of germ cells during testicular regression. Together, these results indicate a shift in the balance between cell proliferation and apoptosis that contributes to the regulation of the spermatogenic cycle and germ cells pool of L. taeniatus kept in captivity.     

A global metagenomic map of urban microbiomes and antimicrobial resistance

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Prehistoric settlement developments in the multi-period sites of south India,Brahmagiri Hill

This paper is focused on the multi-period sites in the core southern Neolithic region of south India to highlight their potential archaeological features and resources to assess land use and settlement patterns adopted by the mid-Holocene societies. Systematic archaeological reworks at the multi-period sites require particular attention to identify the resource locations and non-occupation sites for developing a comprehensive picture of the demographic and social models for explaining how people managed and shared resources within the site environs that continued to exist and operated for more than three thousand years spanning from Neolithic (3000-1200 BCE), Iron Age (1200-300 BCE) and Early History (300 BCE- 500 CE). Published archaeological data on major multi-period sites of south India is reviewed, compiled and attested with exploration findings from the Brahmagiri Hill. Here a fresh approach is made to assess the impact of Ashokan rock edicts on the social fabric and any landscape changes it brought to Isila (Isila is believed to be an early historic townsite at Brahmagiri ).     

Reviewing the Role of DNA (Cytosine-5) Methyltransferase Overexpression in the Cortical GABAergic Dysfunction Associated with Psychosis Vulnerability

In this review, we discuss changes in the regulation of gene expression in the central nervous system (CNS) associated with DNA (cytosine-5) methylation, chromatin remodeling and post-translational covalent modifications of histones.

During brain development, abnormal intrinsic or extrinsic cues may compromise epigenetic processes regulating neural stem cell proliferation and differentiation and thus directly or indirectly could contribute to altered epiphenotypes leading to psychiatric disorders. These mechanisms, that include chromatin remodeling and reversible changes in promoter methylation patterns, are largely expressed by terminally differentiated cortical GABAergic neurons. These neurons are unique among various brain cell subtypes because they express high levels of DNA-methyltransferase-1 (DNMT1). Moreover, DNMT1 expression is further increased in schizophrenia (SZ) and bipolar (BP) disorder brains.

To unravel how this pathological DNMT1 overexpression induces GABAergic neuronal dysfunction in SZ and in other psychoses, we report on how alterations in methylation modify the expression of susceptible vulnerability genes such as reelin or GAD67 in these neurons. The results encourage the view that promoter hypermethylation in GABAergic neurons that occurs in SZ represents a testable target for novel therapeutic strategies to treat this disorder.     

Nouvelles molécules non émettrices de positons : traceurs gamma

The dramatic development of PET tracers, together with doubts related to gamma emitters (especially when considering the molybden production crisis) have questioned the future of such single-photon emitters tracers, mainly when thinking about new and innovative molecules. This paper offers several ways for discussion, and aims to demonstrate that such tracers will have for long time still great interest and usefulness, being complementary rather than alternative with PET tracers.     

Données stratigraphiques, archéologiques et insertion chronologique de la séquence de Longgupo

The site of Longgupo is located north of the subtropical zone and is part of the domain of eastern fauna. The large number of mammal species identified at this site enables clarification of the broad pattern of paleoenvironmental change for the three assemblages from the first stratigraphic sequence (Huang W.-B. excavations). The different species have been classified in four biogeographic groups: subtropical (moderate monsoon), tropical forest (hot and humid climate), montane (cold climate) and prairie (cold and dry climate). Variation in the representation rate of each of these groups enables general reconstruction of the paleoenvironments for the three assemblages identified at Longgupo: a lower assemblage in a hot and humid climate with cold and dry episodes, an intermediate assemblage in a rather cold and dry climate in the lower part, becoming progressively warmer and humid toward the top of the sequence with a monsoon influence more marked than the present day, and an upper assemblage in a rather cold and dry climate. This biochronology and general paleoenvironmental reconstruction are clearly important, but as mentioned above, the stratum by stratum correspondence between the old and new stratigraphic sequences has been quite difficult because the position of material recovered during the early excavations was not recorded.     

Identification of Malassezia species isolated from patients with extensive forms of pityriasis versicolor in Siena,Italy

BackgroundPityriasis versicolor (PV) is an infection caused by various species of Malassezia yeast. There is no agreement in the literature concerning the species of Malassezia and the demographic, clinical, and mycological data.AimsTo prospectively identify Malassezia species isolated from lesions of patients with extensive, long standing and recurrent forms of PV and to estimate the relationship between Malassezia species and the demographic and clinical data of the patients.MethodsAll patients with PV were enrolled over a four-year period. Malassezia species were isolated in cultures and identified by morphological features and physiological tests. In the last 2 years a PCR-based technique was used to confirm the species’ identification.ResultsA total of 74 patients (43 males and 31 females, mean age 39.5 years) were enrolled. Only one species was isolated in 45 patients, and more than one species were identified in the remaining 28 patients (38%). M. globosa was the most frequently isolated (60.3%) species. There was a significant association between the isolation of 2 or more species and the presence of at least one predisposing factor. In the last 29 cases, which were subjected to PCR, there were no differences in the identification of isolated species as compared to traditional methods.ConclusionsThe isolation of more than one species in a single lesion is not infrequent in PV and is related to the presence of one predisposing factor. The isolated species isolated were not influenced by demographic and clinical features. The traditional and more recent (PCR) procedures gave the same results in the isolated species.