Early loss of Xist RNA expression and inactive X chromosome associated chromatin modification in developing primordial germ cells

BACKGROUND: The inactive X chromosome characteristic of female somatic lineages is reactivated during development of the female germ cell lineage. In mouse, analysis of protein products of X-linked genes and/or transgenes located on the X chromosome has indicated that reactivation occurs after primordial germ cells reach the genital ridges. PRINCIPAL FINDINGS/METHODOLOGY: We present evidence that the epigenetic reprogramming of the inactive X-chromosome is initiated earlier than was previously thought, around the time that primordial germ cells (PGCs) migrate through the hindgut. Specifically, we find that Xist RNA expression, the primary signal for establishment of chromosome silencing, is extinguished in migrating PGCs. This is accompanied by displacement of Polycomb-group repressor proteins Eed and Suz(12), and loss of the inactive X associated histone modification, methylation of histone H3 lysine 27. CONCLUSIONS/SIGNIFICANCE: We conclude that X reactivation in primordial germ cells occurs progressively, initiated by extinction of Xist RNA around the time that germ cells migrate through the hindgut to the genital ridges. The events that we observe are reminiscent of X reactivation of the paternal X chromosome in inner cell mass cells of mouse pre-implantation embryos and suggest a unified model in which execution of the pluripotency program represses Xist RNA thereby triggering progressive reversal of epigenetic silencing of the X chromosome.     

Modulation of MAPK activities during egg activation in Drosophila

The mitogen-activated protein kinases (MAPKs) play essential roles during oocyte maturation and egg activation and are also active in somatic cell cycle regulation in many animals. In clams, starfish, ascidians, mice, and frogs, the species-specific timing of MAPK activity during oocyte maturation and egg activation correlates with the different meiotic arrest points of these various organisms. Furthermore, MAPKs have been shown to regulate the meiotic cell cycle in marine invertebrates and vertebrates. The initial trigger for egg activation in insects is different from that of marine invertebrates and vertebrates, and it was not previously known whether changes in MAPK activity accompany egg activation in insects. To examine the regulation of MAPKs during Drosophila egg activation and early embryogenesis, we quantified the levels of phosphorylated (active) forms of ERK, p38 and JNK by western blotting with antibodies specific to the phospho-forms of these kinases. Levels of phospho-ERK, phospho-p38 and phospho-JNK are high in Drosophila oocytes. Upon egg activation, levels of all these phospho- (active) forms of MAPKs decrease. Fertilization is not required for this decrease, consistent with the independence of egg activation from fertilization in Drosophila. The decrease in levels of phospho-MAPK occurs normally in embryos laid by sterile females mutant in the egg activation genes cortex, sarah, and prage. We present a model in which the decrease in MAPK activity is an intermediate step in the pathway leading from the calcium signal that initiates egg activation to the downstream events of activation.     

Seminal influences: Drosophila Acps and the molecular interplay between males and females during reproduction

Successful reproduction requires contributions from both the male and the female. In Drosophila, contributions from the male include accessory gland proteins (Acps) that are components of the seminal fluid. Upon their transfer to the female, Acps affect the female's physiology and behavior. Although primary sequences of Acp genes exhibit variation among species and genera, the conservation of protein biochemical classes in the seminal fluid suggests a conservation of functions. Bioinformatics coupled with molecular and genetic tools available for Drosophila melanogaster has expanded the functional analysis of Acps in recent years to the genomic/proteomic scale. Molecular interplay between Acps and the female enhances her egg production, reduces her receptivity to remating, alters her immune response and feeding behavior, facilitates storage and utilization of sperm in the female and affects her longevity. Here, we provide an overview of the D. melanogaster Acps and integrate the results from several studies that bring the current number of known D. melanogaster Acps to 112. We then discuss several examples of how the female's physiological processes and behaviors are mediated by interactions between Acps and the female. Understanding how Acps elicit particular female responses will provide insights into reproductive biology and chemical communication, tools for analyzing models of sexual cooperation and/or sexual conflict, and information potentially useful for strategies for managing insect pests.     

Use of somatic cell nuclear transfer to study meiosis in female cattle carrying a sex-dependent fertility-impairing X-chromosome abnormality

Animal models have played an important part in establishing our knowledge base on reproduction, development, and the occurrence and impact of chromosome abnormalities. Translocations involving the X chromosome and an autosome are unique in that they elicit sex-dependent infertility, with male carriers rendered sterile by synaptic anomalies during meiosis, whereas female carriers conceive but repeatedly abort. Until now the limited access to relevant fetal oocytes has precluded direct study of meiotic events in female carriers. Because somatic cell nuclear transfer (SCNT) circumvents meiotic problems associated with fertility disturbances in translocation carriers, we used SCNT to generate embryos, fetuses, and calves from a cell line derived from a deceased subfertile X-autosome translocation carrier cow to study the meiotic configurations in carrier oocytes. Data from 33 replicates involving 2470 oocyte-donor-cell complexes were assessed for blastocyst development and of these, 42 blastocysts were transferred to 21 recipients. Fourteen pregnancies were detected on day 35 of gestation. One of these was sacrificed for ovary retrieval on day 94 and three went to term. Features of oocytes from the fetal ovary and from the newborn ovaries were examined. Of the pachytene spreads analyzed, 16%, 82%, and 1.5% exhibited quadrivalent, trivalent/univalent, and bivalent/univalent/univalent structures, respectively, whereas among the diakinesis/metaphase I spreads, 16% ring, 75% chain, and 8.3% bivalent/bivalent configurations were noted, suggesting that the low fertility among female carriers may be related to synaptic errors in a predominant proportion of oocytes. Our results indicate that fibroblasts carrying the X-autosome translocation can be used for SCNT to produce embryos, fetuses, and newborn clones to study such basic aspects of development as meiosis and to generate carriers that cannot easily be reproduced by conventional breeding.     

Morphogenesis control in Candida albicans and Candida dubliniensis through signaling molecules produced by planktonic and biofilm cells

Morphogenesis control by chemical signaling molecules is beginning to be highlighted in Candida biology. The present study focuses on morphogenic compounds produced in situ by Candida albicans and Candida dubliniensis during planktonic and biofilm growth that may at least partially substantiate the effect promoted by supernatants in morphogenesis. For both species, planktonic versus biofilm supernatants were analyzed by headspace-solid-phase microextraction and gas chromatography-mass spectrometry. Both planktonic cells and biofilm supernatants of C. albicans and C. dubliniensis contained isoamyl alcohol, 2-phenylethanol, 1-dodecanol, E-nerolidol, and E,E-farnesol. Alcohol secretion profiles were species, culture mode, and growth time specific. The addition of exogenous alcohols to the cultures of both species inhibited the morphological transition from the yeast to the filamentous form by up to 50%. The physiological role of these alcohols was put to evidence by comparing the effects of a 96-h cultured supernatant with synthetic mixtures containing isoamyl alcohol, 2-phenylethanol, E-nerolidol, and E,E-farnesol at concentrations determined herein. All synthetic mixtures elicited a morphological effect similar to that observed for the corresponding supernatants when used to treat C. albicans and C. dubliniensis cultures, except for the effect of the 96-h C. dubliniensis planktonic supernatant culture on C. albicans. Overall, these results reveal a group of alcohol extracellular signaling molecules that are biologically active with C. albicans and C. dubliniensis morphogenesis.     

Cardiovascular and ventilatory interactions in the facultative air-breathing teleost Pangasianodon hypophthalmus

Journal of Comparative Physiology B - All vertebrates possess baroreceptors monitoring arterial blood pressure and eliciting reflexive changes in vascular resistance and heart rate in response to...     

Follow-up assessment of patients with Pure Neural Leprosy in a reference center in Rio de Janeiro—Brazil

IntroductionPure Neural Leprosy (PNL) is a rare clinical form of leprosy in which patients do not present with the classical skin lesions but have a high burden of the disability associated with the disease. Clinical characteristics and follow up of patients in PNL are still poorly described in the literature.ObjectiveThis paper aims to describe the clinical, electrophysiological and histopathological characteristics of PNL patients, as well as their evolution after multidrug therapy (MDT).MethodsFifty-two PNL patients were selected. Clinical, nerve conduction studies (NCS), histopathological and anti-PGL-1serology were evaluated. Patients were also assessed monthly during the MDT. At the end of the MDT, all of the patients had a new neurological examination and 44 were submitted to another NCS.ResultsParesthesia was the complaint most frequently reported by patients, and in the neurological examination the most common pattern observed was impairment in sensory and motor examination and a mononeuropathy multiplex. Painful nerve enlargement, a classical symptom of leprosy neuropathy, was observed in a minority of patients and in the motor NCS axonal injuries, alone or in combination with demyelinating features, were the most commonly observed. 88% of the patients did not present any leprosy reaction during MDT. There was no statistically significant difference between the neurological examinations, nor the NCS pattern, performed before and after the MDT.DiscussionThe classical hallmarks of leprosy neuropathy are not always present in PNL making the diagnosis even more challenging. Nerve biopsy is an important tool for PNL diagnosis as it may guide therapeutic decisions. This paper highlights unique characteristics of PNL in the spectrum of leprosy in an attempt to facilitate the diagnosis and management of these patients.     

68Ga-PSMA-HBED-CC PET/MRI is superior to multiparametric magnetic resonance imaging in men with biochemical recurrent prostate cancer: A prospective single-institutional study

BackgroundThe primary objective was to compare the overall diagnostic performance, presented as detection rate of ⁶⁸Ga-PSMA-HBED-CC positron emission tomography/magnetic resonance imaging (PSMA PET/MRI) versus conventional, multiparametric MRI (mpMRI) in a population of patients with biochemically recurrent prostate cancer. In conjunction with this analysis, secondary objectives included the evaluation of the detection rate stratified by PSA levels and primary treatment modality.MethodsA total of 165 PSMA PET MRI were performed from April 2018 to May 2021, of whom 108 were presenting for biochemical recurrent disease. The PSMA PET vertex to thigh were read by two different board-certified nuclear medicine physicians while the MRI head and neck, chest, abdomen, and pelvis (with dedicated, PI-RADS compliant multiparametric prostate MRI) were read by two board certified diagnostic radiologists.AnalysisPSMA PET/MRI had a higher detection rate than mpMRI when evaluating patients with biochemical recurrence (BCR) with similar results demonstrated when sub-analysis was performed using PSA levels, primary treatment modality, and time since androgen deprivation therapy. Our study also showed PSMA PET/MRI had a higher sensitivity than mpMRI.DiscussionOur findings demonstrate that PSMA PET/MRI is a better imaging modality in the detection of disease in the setting of BCR when compared to MRI alone. Combined utility with PSMA PET/MRI is a powerful tool which can aid in not only the detection of disease, but also guide in treatment planning for prostate cancer patients.