Identification of voltage-dependent Ca2+ channels in sea urchin sperm

AbstractFunctional evidence indicates that voltage-dependent Ca2+ (Cav) channels participate in sea urchin sperm motility and the acrosome reaction (AR), however, their molecular identity remains unknown. We have identified transcripts for two Ca2+ channel α1 subunits in sea urchin testis similar in sequence to Cav1.2 and Cav2.3. Antibodies against rat Cav1.2 and Cav2.3 channels differentially label proteins in the flagella and acrosome of mature sea urchin sperm. The Cav channel antagonists nifedipine and nimodipine, which inhibit the AR, diminish the intracellular Ca2+ elevation induced by a K+-induced depolarization in valinomycin-treated sperm. These findings reveal that Cav1.2 and Cav2.3 channels could participate in motility and/or the AR in sea urchin sperm

Drug induced iatrogenic Cushing’s syndrome

Drug-induced (iatrogenic) Cushing's syndrome results from excessive or prolonged exposure to glucocorticoids, commonly prescribed for autoimmune, inflammatory, and hematological disorders due to their anti-inflammatory, immunosuppressive, and proapoptotic effects. Despite their therapeutic benefits, these medications can lead to a range of multisystemic symptoms mirroring those of endogenous Cushing’s syndrome. This review aims to elucidate the causes, clinical presentation, diagnosis, and management of iatrogenic Cushing's syndrome, emphasizing awareness of medications that can trigger its onset. The following review covers cortisol physiology, Cushing's syndrome etiology and subtypes, hypercortisolism complications and prognosis, and strategies for glucocorticoid withdrawal. This article synthesizes key findings and recommendations, highlighting challenges and controversies in the diagnosis and treatment of iatrogenic Cushing's syndrome

Characterization of Selective Antibacterial Peptides by Polarity Index

In the recent decades, antibacterial peptides have occupied a strategic position for pharmaceutical drug applications and became subject of intense research activities since they are used to strengthen the immune system of all living organisms by protecting them from pathogenic bacteria. This work proposes a simple and easy statistical/computational method through a peptide polarity index measure by which an antibacterial peptide subgroup can be efficiently identified, that is, characterized by a high toxicity to bacterial membranes but presents a low toxicity to mammal cells. These peptides also have the feature not to adopt to an alpha-helicoidal structure in aqueous solution. The double-blind test carried out to the whole Antimicrobial Peptide Database (November 2011) showed an accuracy of 90% applying the polarity index method for the identification of such antibacterial peptide groups

Characterization of growth and metabolism of the haloalkaliphile Natronomonas pharaonis

Natronomonas pharaonis is an archaeon adapted to two extreme conditions: high salt concentration and alkaline pH. It has become one of the model organisms for the study of extremophilic life. Here, we present a genome-scale, manually curated metabolic reconstruction for the microorganism. The reconstruction itself represents a knowledge base of the haloalkaliphile's metabolism and, as such, would greatly assist further investigations on archaeal pathways. In addition, we experimentally determined several parameters relevant to growth, including a characterization of the biomass composition and a quantification of carbon and oxygen consumption. Using the metabolic reconstruction and the experimental data, we formulated a constraints-based model which we used to analyze the behavior of the archaeon when grown on a single carbon source. Results of the analysis include the finding that Natronomonas pharaonis, when grown aerobically on acetate, uses a carbon to oxygen consumption ratio that is theoretically near-optimal with respect to growth and energy production. This supports the hypothesis that, under simple conditions, the microorganism optimizes its metabolism with respect to the two objectives. We also found that the archaeon has a very low carbon efficiency of only about 35%. This inefficiency is probably due to a very low P/O ratio as well as to the other difficulties posed by its extreme environment

LEPRA LEPROMATOSA PENEAL EN PACIENTE CON ENFERMEDAD DE CHAGAS. REPORTE DE UN CASO

Se presenta el caso de un paciente masculino de 52 años con fimosis secundaria a una masa pseudotumoral prepucial. El paciente presentaba una historia de enfermedad de Hansen con afectación de piel, laringe y bronquios. Previa a la circuncisión, el examen físico revelaba, además de las alteraciones lepromatosas, un mega esófago secundario a estenosis en la porción distal. El análisis laboratorial mediante la técnica de ELISA dio positivo para Trypanosoma cruzi, patógeno responsable de la enfermedad de Chagas. Sólo pudimos encontrar un caso previo reportado de lepra lepromatosa con afectación prepucial. La coexistencia de lepra y miocardiopatía chagásica es inusual pero bien conocida por casos reportados en Brasil e India. Sin embargo, de acuerdo a nuestros conocimientos, éste es el primer caso reportado de una sociación entre lepra lepromatosa y mega esófago chagásico en un paciente con fimosis

Systems analysis of bioenergetics and growth of the extreme halophile Halobacterium salinarum

Halobacterium salinarum is a bioenergetically flexible, halophilic microorganism that can generate energy by respiration, photosynthesis, and the fermentation of arginine. In a previous study, using a genome-scale metabolic model, we have shown that the archaeon unexpectedly degrades essential amino acids under aerobic conditions, a behavior that can lead to the termination of growth earlier than necessary. Here, we further integratively investigate energy generation, nutrient utilization, and biomass production using an extended methodology that accounts for dynamically changing transport patterns, including those that arise from interactions among the supplied metabolites. Moreover, we widen the scope of our analysis to include phototrophic conditions to explore the interplay between different bioenergetic modes. Surprisingly, we found that cells also degrade essential amino acids even during phototropy, when energy should already be abundant. We also found that under both conditions considerable amounts of nutrients that were taken up were neither incorporated into the biomass nor used as respiratory substrates, implying the considerable production and accumulation of several metabolites in the medium. Some of these are likely the products of forms of overflow metabolism. In addition, our results also show that arginine fermentation, contrary to what is typically assumed, occurs simultaneously with respiration and photosynthesis and can contribute energy in levels that are comparable to the primary bioenergetic modes, if not more. These findings portray a picture that the organism takes an approach toward growth that favors the here and now, even at the cost of longer-term concerns. We believe that the seemingly "greedy" behavior exhibited actually consists of adaptations by the organism to its natural environments, where nutrients are not only irregularly available but may altogether be absent for extended periods that may span several years. Such a setting probably predisposed the cells to grow as much as possible when the conditions become favorable

Consecutive renal biopsy in a cohort of patients with lupus nephritis of the Colombian Caribbean

Background: Renal biopsy is the gold standard for the diagnosis and classification of lupus nephritis (LN). However, a consecutive biopsy can predict the clinical course and optimize the therapeutic strategies. Objectives: To compare the histopathological findings with clinical responses. Patients and Methods: Thirty patients with active LN were included. Renal biopsies were performed at the time of diagnosis and subsequently under clinical criteria according to consensus of Spanish Society of Nephrology. The response to treatment was defined as complete response, partial responder or non-responder. The histological change in second biopsy towards LN classes I, II or III/IV-C was defined as histological response (HR). Results: In initial renal biopsy, 28 (93%) patients showed proliferative LN; III-A or A/C (n; 7), IV-A or A/C (n: 19) and mixed; III+IV/V (n; 2). LN class V was presented in two cases. The clinical response was; complete response (10%), partial response (20%), and non-response (70%). HR was manifested in 37% and non-histologic response in 63% of patients. Around 33% of patients with complete response/partial response showed active lesions in the consecutive renal biopsy. Conclusions: In Colombian Caribbean, LN is aggressive and refractory to treatment. The consecutive renal biopsy allowed to demonstrate the persistence of the activity of the lesion in almost half of the patients, which may provide additional information to create better response criteria. The consecutive renal biopsy is a tool that allows improving the evaluation of the response to treatment in the LN

Stellar Population gradients in galaxy discs from the CALIFA survey

While studies of gas-phase metallicity gradients in disc galaxies are common, very little has been done in the acquisition of stellar abundance gradients in the same regions. We present here a comparative study of the stellar metallicity and age distributions in a sample of 62 nearly face-on, spiral galaxies with and without bars, using data from the CALIFA survey. We measure the slopes of the gradients and study their relation with other properties of the galaxies. We find that the mean stellar age and metallicity gradients in the disc are shallow and negative. Furthermore, when normalized to the effective radius of the disc, the slope of the stellar population gradients does not correlate with the mass or with the morphological type of the galaxies. Contrary to this, the values of both age and metallicity at $\sim$2.5 scale-lengths correlate with the central velocity dispersion in a similar manner to the central values of the bulges, although bulges show, on average, older ages and higher metallicities than the discs. One of the goals of the present paper is to test the theoretical prediction that non-linear coupling between the bar and the spiral arms is an efficient mechanism for producing radial migrations across significant distances within discs. The process of radial migration should flatten the stellar metallicity gradient with time and, therefore, we would expect flatter stellar metallicity gradients in barred galaxies. However, we do not find any difference in the metallicity or age gradients in galaxies with without bars. We discuss possible scenarios that can lead to this absence of difference.Comment: 24 pages, 17 figures, accepted for publication in A&

Ferromagnetism in Oriented Graphite Samples

We have studied the magnetization of various, well characterized samples of highly oriented pyrolitic graphite (HOPG), Kish graphite and natural graphite to investigate the recently reported ferromagnetic-like signal and its possible relation to ferromagnetic impurities. The magnetization results obtained for HOPG samples for applied fields parallel to the graphene layers - to minimize the diamagnetic background - show no correlation with the magnetic impurity concentration. Our overall results suggest an intrinsic origin for the ferromagnetism found in graphite. We discuss possible origins of the ferromagnetic signal.Comment: 11 figure

The Sensitivity of HAWC to High-Mass Dark Matter Annihilations

The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross-section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross-sections below thermal. HAWC should also be sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross-section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.Comment: 15 pages, 4 figures, version to be published in PR