Cortisol-Induced Masculinization: Does Thermal Stress Affect Gonadal Fate in Pejerrey, a Teleost Fish with Temperature-Dependent Sex Determination?

BACKGROUND: Gonadal fate in many reptiles, fish, and amphibians is modulated by the temperature experienced during a critical period early in life (temperature-dependent sex determination; TSD). Several molecular processes involved in TSD have been described but how the animals "sense" environmental temperature remains unknown. We examined whether the stress-related hormone cortisol mediates between temperature and sex differentiation of pejerrey, a gonochoristic teleost fish with marked TSD, and the possibility that it involves glucocorticoid receptor- and/or steroid biosynthesis-modulation. METHODOLOGY/PRINCIPAL FINDINGS: Larvae maintained during the period of gonadal sex differentiation at a masculinizing temperature (29 degrees C; 100% males) consistently had higher cortisol, 11-ketotestoterone (11-KT), and testosterone (T) titres than those at a feminizing temperature (17 degrees C; 100% females). Cortisol-treated animals had elevated 11-KT and T, and showed a typical molecular signature of masculinization including amh upregulation, cyp19a1a downregulation, and higher incidence of gonadal apoptosis during sex differentiation. Administration of cortisol and a non-metabolizable glucocorticoid receptor (GR) agonist (Dexamethasone) to larvae at a "sexually neutral" temperature (24 degrees C) caused significant increases in the proportion of males. CONCLUSIONS/SIGNIFICANCE: Our results suggest a role of cortisol in the masculinization of pejerrey and provide a possible link between stress and testicular differentiation in this gonochoristic TSD species. Cortisol role or roles during TSD of pejerrey seem(s) to involve both androgen biosynthesis- and GR-mediated processes. These findings and recent reports of cortisol effects on sex determination of sequential hermaphroditic fishes, TSD reptiles, and birds provide support to the notion that stress responses might be involved in various forms of environmental sex determination

Calculation of The Band Gap Energy and Study of Cross Luminescence in Alkaline-Earth Dihalide Crystals

The band gap energy as well as the possibility of cross luminescence processes in alkaline-earth dihalide crystals have been calculated using the ab initio Perturbed-Ion (PI) model. The gap is calculated in several ways: as a difference between one-electron energy eigenvalues and as a difference between total energies of appropriate electronic states of the crystal, both at the HF level and with inclusion of Coulomb correlation effects. In order to study the possibility of ocurrence of cross luminescence in these materials, the energy difference between the valence band and the upmost core band for some representative crystals has been calculated. Both calculated band gap energies and cross luminescence predictions compare very well with the available experimental results.Comment: LaTeX file containing 8 pages plus 1 postscript figure. Final version accepted for publication in The Journal of the Physical Society of Japan. It contains a more complete list of references, as well as a more detailed comparison with previous theoretical investigations on the subjec

Effects of Distribution of Helium Bubbles on the Tensile Properties and Swelling of Neutron-Irradiated and Annealed Beryllium(Metallurgy)

Tensile properties at 250℃ and swelling of beryllium, irradiated to 5×10^n/cm^2 at about 450℃ and subsequently annealed for up to 1000 h at 800, 900 and 1000℃ were measured to elucidate the effect of helium bubbles formed during the annealing. Size and distribution of the bubbles in the matrix, grain surfaces, and grain edges and corners, respectively, were observed by a transmission or scanning electron microscope. It is concluded that the dense distribution of fine bubbles in the matrix contributes to strengthening of the metal, while bubbles in the grain edges and corners contribute to the swelling

Recent Trends in the Incidence, Treatment, and Prognosis of Patients With Heart Failure and Atrial Fibrillation (the Worcester Heart Failure Study)

Atrial fibrillation (AF) and heart failure (HF) are common cardiovascular diseases and the co-occurrence of AF and HF has been associated with reduced survival. Data are needed on the potentially changing trends in the characteristics, treatment, and prognosis of patients with acute decompensated HF (ADHF) and AF. The study population consisted of 9,748 patients hospitalized with ADHF at 11 hospitals in the Worcester, Massachusetts, metropolitan area during 4 study years (1995, 2000, 2002, and 2004). Of the 9,748 patients admitted with ADHF, 3,868 (39.7%) had a history of AF and 449 (4.6%) developed new-onset AF during hospitalization. The rates of new-onset AF remained stable (4.9% in 1995; 5.0% in 2004), but the proportion of patients with pre-existing AF (34.5% in 1995; 41.6% in 2004) increased over time. New-onset and pre-existing AF were associated with older age, but pre-existing AF was more closely linked to a greater co-morbid disease burden. The use of HF therapies did not differ greatly by AF status. Despite this, new-onset AF was associated with a longer length of stay (7.5 vs 6.1 days) and greater in-hospital death rates (11.4% vs 6.6%). In contrast, pre-existing AF was associated with lower rates of postdischarge survival compared to patients with no AF (p In conclusion, AF was common among patients with ADHF, and the proportion of ADHF patients with co-occurring AF increased during the study period. Despite improving trends in survival, patients with ADHF and AF are at increased risk of in-hospital and postdischarge mortality

Cortisol-Induced Masculinization: Does Thermal Stress Affect Gonadal Fate in Pejerrey, a Teleost Fish with Temperature-Dependent Sex Determination? Plos One 4(8

Background: Gonadal fate in many reptiles, fish, and amphibians is modulated by the temperature experienced during a critical period early in life (temperature-dependent sex determination; TSD). Several molecular processes involved in TSD have been described but how the animals ‘‘sense’ ’ environmental temperature remains unknown. We examined whether the stress-related hormone cortisol mediates between temperature and sex differentiation of pejerrey, a gonochoristic teleost fish with marked TSD, and the possibility that it involves glucocorticoid receptor- and/or steroid biosynthesismodulation. Methodology/Principal Findings: Larvae maintained during the period of gonadal sex differentiation at a masculinizing temperature (29uC; 100 % males) consistently had higher cortisol, 11-ketotestoterone (11-KT), and testosterone (T) titres than those at a feminizing temperature (17uC; 100 % females). Cortisol-treated animals had elevated 11-KT and T, and showed a typical molecular signature of masculinization including amh upregulation, cyp19a1a downregulation, and higher incidence of gonadal apoptosis during sex differentiation. Administration of cortisol and a non-metabolizable glucocorticoid receptor (GR) agonist (Dexamethasone) to larvae at a ‘‘sexually neutral’ ’ temperature (24uC) caused significant increases in the proportion of males. Conclusions/Significance: Our results suggest a role of cortisol in the masculinization of pejerrey and provide a possible link between stress and testicular differentiation in this gonochoristic TSD species. Cortisol role or roles during TSD of pejerre