Pre-fertilization gamete thermal environment influences reproductive success, unmasking opposing sex-specific responses in Atlantic salmon (Salmo salar).

The environment gametes perform in just before fertilization is increasingly recognized to affect offspring fitness, yet the contributions of male and female gametes and their adaptive significance remain largely unexplored. Here, we investigated gametic thermal plasticity and its effects on hatching success and embryo performance in Atlantic salmon (Salmo salar). Eggs and sperm were incubated overnight at 2°C or 8°C, temperatures within the optimal thermal range of this species. Crosses between warm- and cold-incubated gametes were compared using a full-factorial design, with half of each clutch reared in cold temperatures and the other in warm temperatures. This allowed disentangling single-sex interaction effects when pre-fertilization temperature of gametes mismatched embryonic conditions. Pre-fertilization temperature influenced hatch timing and synchrony, and matching sperm and embryo temperatures resulted in earlier hatching. Warm incubation benefited eggs but harmed sperm, reducing the hatching success and, overall, gametic thermal plasticity did not enhance offspring fitness, indicating vulnerability to thermal changes. We highlight the sensitivity of male gametes to higher temperatures, and that gamete acclimation may not effectively buffer against deleterious effects of thermal fluctuations. From an applied angle, we propose the differential storage of male and female gametes as a tool to enhance sustainability within the hatcheries.

Frequency-dependent viscosity of salmon ovarian fluid has biophysical implications for sperm-egg interactions.

Gamete-level sexual selection of externally fertilising species is usually achieved by modifying sperm behaviour with mechanisms that alter the chemical environment in which gametes perform. In fish, this can be accomplished through the ovarian fluid, a substance released with the eggs at spawning. While the biochemical effects of ovarian fluid in relation to sperm energetics have been investigated, the influence of the physical environment in which sperm compete remains poorly explored. Our objective was therefore to gain insights on the physical structure of this fluid and potential impacts on reproduction. Using soft-matter physics approaches of steady-state and oscillatory viscosity measurements, we subjected wild Atlantic salmon ovarian fluids to variable shear stresses and frequencies resembling those exerted by sperm swimming through the fluid near eggs. We show that this fluid, which in its relaxed state is a gel-like substance, displays a non-Newtonian viscoelastic and shear-thinning profile, where the viscosity decreases with increasing shear rates. We concurrently find that this fluid obeys the Cox-Merz rule below 7.6 Hz and infringes it above this level, thus indicating a shear-thickening phase where viscosity increases provided it is probed gently enough. This suggests the presence of a unique frequency-dependent structural network with relevant implications for sperm energetics and fertilisation dynamics. This article has an associated ECR Spotlight interview with Marco Graziano.

Efficacy, renal safety and tolerability of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in elderly patients with type 2 diabetes: A real-world experience.

AIMS: To evaluate efficacy, renal safety and tolerability of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in a cohort of patients with type 2 diabetes (T2DM) aged ≥65 years. METHODS: We retrospectively evaluated 364 elderly individuals with T2DM starting SGLT2i from June 2015 to June 2018. Patients were divided into 2 subgroups based on median age (70 years). Linear mixed effect models were used to estimate changes in glycated hemoglobin (HbA1c), body mass index (BMI), and glomerular filtration rate (eGFR). SGLT2i discontinuation rate and causes of treatment interruption were also recorded. RESULTS: A significantly higher percentage of patients achieved HbA1c <7.5% (46.7% vs. 31.6%, p < 0.01) and <8.0% (68.9% vs. 47.2%, p < 0.01) compared to baseline. Each year of therapy was associated with an average HbA1c decrease of 0.34% (p < 0.01) and BMI loss of 0.71 kg/m2 (p < 0.01), without significant interaction across age classes. In the younger group eGFR increased by 1.02 ml/min/year, while in the older group it declined by 0.42 ml/min/year (p = 0.08). Overall discontinuation rate during the follow-up period was similar across age groups (34.2% vs. 36.1%, long-rank p = 0.26). Genitourinary infections were the most frequent cause of treatment interruption (15.8% vs. 17.2%, p = 0.69) in both study groups, while persistent eGFR decline (4.4%) and orthostatic hypotension (1.7%) were only present in older age class. CONCLUSIONS: Efficacy, renal safety and tolerability of SGLT2i were similar in people >70 compared to 65-70 years of age, suggesting that a wider use should not be worried even in the elderly. However, some caution must be paid to the occurrence of persistent eGFR decline and orthostatic hypotension, especially in patients >70 years old.

Prevalence and Clinical Characteristics of Children and Adolescents with Metabolically Healthy Obesity: Role of Insulin Sensitivity.

Obesity represents a major risk factor for metabolic disorders, but some individuals, "metabolically healthy" (MHO), show less clinical evidence of these complications, in contrast to "metabolically unhealthy" (MUO) individuals. The aim of this cross-sectional study is to assess the prevalence of the MHO phenotype in a cohort of 246 overweight/obese Italian children and adolescents, and to evaluate their characteristics and the role of insulin resistance. Homeostasis model assessment-insulin resistance (HOMA-IR), insulin sensitivity index (ISI), insulinogenic index (IGI) and disposition index (DI) were all calculated from the Oral Glucose Tolerance Test (OGTT). MHO was defined by either: (1) HOMA-IR < 2.5 (MHO-IRes), or (2) absence of the criteria for metabolic syndrome (MHO-MetS). The MHO prevalence, according to MHO-MetS or MHO-IRes criteria, was 37.4% and 15.8%, respectively. ISI was the strongest predictor of the MHO phenotype, independently associated with both MHO-IRes and MHO-MetS. The MHO-MetS group was further subdivided into insulin sensitive or insulin resistant on the basis of HOMA-IR (either < or ≥ 2.5). Insulin sensitive MHO-MetS patients had a better metabolic profile compared to both insulin resistant MHO-MetS and MUO-MetS individuals. These data underscore the relevance of insulin sensitivity to identifying, among young individuals with overweight/obesity, the ones who have a more favorable metabolic phenotype.

Influence of the Mediterranean and Ketogenic Diets on Cognitive Status and Decline: A Narrative Review.

Alzheimer's disease (AD) is the most common form of senile dementia, accounting for up to 70% of dementia cases. AD is a slowly progressive disease, which causes global mental deterioration by affecting various cognitive areas. A growing body of evidence has demonstrated that lifestyle habits and nutritional patterns could delay the natural course of the neurodegeneration process. There is no single dietary pattern unequivocally proven to prevent AD. Nevertheless, epidemiological data suggest that by adopting several dietary habits, especially if accompanied with a healthy lifestyle, the negative consequences of AD could potentially be delayed. Alongside with others, two specific eating patterns have been well investigated concerning their potential beneficial effect on cognitive status: the Mediterranean diet (MedDi) and the Ketogenic Diet (KD). Despite the different underlying mechanisms, both of them have demonstrated a fairly profitable role in reducing or delaying cognitive impairment. The aim of the present narrative review is to overview the existing research on the efficacy of MedDi and KD against AD-related cognitive decline, focusing on the proposed protective mechanisms of action. Although the current knowledge on this complex topic does not allow us, at this point, to make exhaustive conclusions, this information could be of help in order to better characterize the possible role of MedDi and KD as nonpharmacological therapies in the treatment of AD and, more generically, of neurodegenerative disorders.

Adipose Tissue, Obesity and Adiponectin: Role in Endocrine Cancer Risk.

Adipose tissue has been recognized as a complex organ with endocrine and metabolic roles. The excess of fat mass, as occurs during overweight and obesity states, alters the regulation of adipose tissue, contributing to the development of obesity-related disorders. In this regard, many epidemiological studies shown an association between obesity and numerous types of malignancies, comprising those linked to the endocrine system (e.g., breast, endometrial, ovarian, thyroid and prostate cancers). Multiple factors may contribute to this phenomenon, such as hyperinsulinemia, dyslipidemia, oxidative stress, inflammation, abnormal adipokines secretion and metabolism. Among adipokines, growing interest has been placed in recent years on adiponectin (APN) and on its role in carcinogenesis. APN is secreted by adipose tissue and exerts both anti-inflammatory and anti-proliferative actions. It has been demonstrated that APN is drastically decreased in obese individuals and that it can play a crucial role in tumor growth. Although literature data on the impact of APN on carcinogenesis are sometimes conflicting, the most accredited hypothesis is that it has a protective action, preventing cancer development and progression. The aim of the present review is to summarize the currently available evidence on the involvement of APN and its signaling in the etiology of cancer, focusing on endocrine malignancies.

Metal Resistance in Bacteria from Contaminated Arctic Sediment is Driven by Metal Local Inputs.

Anthropogenic impact over the Pasvik River (Arctic Norway) is mainly caused by emissions from runoff from smelter and mine wastes, as well as by domestic sewage from the Russian, Norwegian, and Finnish settlements situated on its catchment area. In this study, sediment samples from sites within the Pasvik River area with different histories of metal input were analyzed for metal contamination and occurrence of metal-resistant bacteria in late spring and summer of 2014. The major differences in microbial and chemical parameters were mostly dependent on local inputs than seasonality. Higher concentrations of metals were generally detected in July rather than May, with inner stations that became particularly enriched in Cr, Ni, Cu, and Zn, but without significant differences. Bacterial resistance to metals, which resulted from viable counts on amended agar plates, was in the order Ni2+>Pb2+>Co2+>Zn2+>Cu2+>Cd2+>Hg2+, with higher values that were generally determined at inner stations. Among a total of 286 bacterial isolates (mainly achieved from Ni- and Pb-amended plates), the 7.2% showed multiresistance at increasing metal concentration (up to 10,000 ppm). Selected multiresistant isolates belonged to the genera Stenotrophomonas, Arthrobacter, and Serratia. Results highlighted that bacteria, rapidly responding to changing conditions, could be considered as true indicators of the harmful effect caused by contaminants on human health and environment and suggested their potential application in bioremediation processes of metal-polluted cold sites.

Occurrence of the black yeast Hortaea werneckii in the Mediterranean Sea.

The occurrence of cultivable fungi was investigated along the water column (25-2500 m depth) of four off-shore stations in the Mediterranean basin. An unexpected high abundance of fungi, accompanied by a scarce biodiversity, was observed up to 2500 m depth. The black yeast Hortaea werneckii, known to be one of the most salt tolerant eukaryotic organisms, was isolated for the first time from the Mediterranean Sea, and it was the dominant fungus present in seawater in almost all stations and depths, suggesting its ubiquitous distribution. Isolation of cultivable strains allowed their phylogenetic and taxonomic characterization, and demonstrated that almost all the retrieved fungal species should be considered of terrestrial origin, but well adapted to survive and reproduce at temperature and salinity conditions of the Mediterranean seawater.

Swimming exercise to control precocious maturation in male seabass (Dicentrarchus labrax).

BACKGROUND: Male European seabass, already predominant (~ 70%) in cultured stocks, show a high incidence (20-30%) of precocious sexual maturation under current aquaculture practices, leading to important economic losses for the industry. In view of the known modulation of reproductive development by swimming exercise in other teleost species, we aimed at investigating the effects of sustained swimming on reproductive development in seabass males during the first year of life in order to determine if swimming could potentially reduce precocious sexual maturation. METHODS: Pre-pubertal seabass (3.91 ± 0.22 g of body weight (BW)) were subjected to a 10 week swimming regime at their optimal swimming speed (Uopt) in an oval-shaped Brett-type flume or kept at rest during this period. Using Blazka-type swim tunnels, Uopt was determined three times during the course of the experiment: 0.66 m s- 1 at 19 ± 1 g BW, 10.2 ± 0.2 cm of standard length (SL) (week 1); 0.69 m s- 1 at 38 ± 3 g BW, 12.7 ± 0.3 cm SL (week 5), and also 0.69 m s- 1 at 77 ± 7 g BW, 15.7 ± 0.5 cm SL (week 9). Every 2 weeks, size and gonadal weight were monitored in the exercised (N = 15) and non-exercised fish (N = 15). After 10 weeks, exercised and non-exercised males were sampled to determine plasma 11-ketotestosterone levels, testicular mRNA expression levels of genes involved in steroidogenesis and gametogenesis by qPCR, as well as the relative abundance of germ cells representing the different spermatogenic stages by histological examination. RESULTS: Our results indicate that sustained swimming exercise at Uopt delays testicular development in male European seabass as evidenced by decreased gonado-somatic index, slower progression of testicular development and by reduced mRNA expression levels of follicle stimulating hormone receptor (fshR), 3-beta-hydroxysteroid dehydrogenase (3ßhsd), 11-beta hydroxysteroid dehydrogenase (11ßhsd), estrogen receptor-beta (erß2), anti-mullerian hormone (amh), structural maintenance of chromosomes protein 1B (smc1ß), inhibin beta A (inhba) and gonado-somal derived factor 1 (gsdf1) in exercised males as compared with the non-exercised males. CONCLUSIONS: Swimming exercise may represent a natural and non-invasive tool to reduce the incidence of sexually precocious males in seabass aquaculture.

Biosurfactant production by hydrocarbon-degrading Brevibacterium and Vibrio isolates from the sea pen Pteroeides spinosum (Ellis, 1764).

Among filter-feeders, pennatulids are the most complex and polymorphic members of the cnidarian class Anthozoa. They display a wide distribution throughout all the oceans, constituting a significant component of the sessile megafauna from intertidal to abyssal depths. In this study, a total of 118 bacterial isolates from enrichment cultures, carried out with homogenates of the sea pen Pteroeides spinosum (Ellis, 1764), were screened for hydrocarbon utilization by using the 2,6-dichlorophenol indophenol assay. Among them, 83 hydrocarbon-oxidizing isolates were analyzed for biosurfactant production by standard screening tests (i.e., emulsifying activity, E24 detection, surface tension measurement, microplate assay). The 16S rRNA gene sequencing revealed the affiliation of the most promising isolates to the genera Brevibacterium and Vibrio. Biosurfactant production resulted strongly affected by salinity and temperature conditions, and occurred in the presence of diesel oil and/or crude oil, whereas no production was observed when isolates were grown on tetradecane. The strains resulted able to create stable emulsions, thus suggesting the production of biosurfactants. Further analyses revealed a glycolipidic nature of the biosurfactant extracted from Vibrio sp. PBN295, a genus that has been only recently reported as biosurfactant producer. Results suggest that pennatulids could represent a novel source for the isolation of hydrocarbon-oxidizing bacteria with potential in biosurfactant production.

Biosurfactant activity, heavy metal tolerance and characterization of Joostella strain A8 from the Mediterranean polychaete Megalomma claparedei (Gravier, 1906).

The effect of heavy metals on the activity of biosurfactants produced by Joostella strain A8 from the polychaete Megalomma claparedei was investigated. Biosurfactant activity was first improved by evaluating the influence of abiotic parameters. Higher E(24) indices were achieved at 25 °C in mineral salt medium supplemented with 2 % glucose, 3 % sodium chloride (w/v) and 0.1 % ammonium chloride (w/v). Considerable surface tension reduction was never recorded. Heavy metal tolerance was preliminarily assayed by plate diffusion method resulting in the order of toxicity Cd > Cu > Zn. The activity of biosurfactants was then evaluated in the presence of heavy metals at different concentrations in liquid cultures that were incubated under optimal conditions for biosurfactant activity. The production of stable emulsions resulted generally higher in the presence of metals. These findings suggest that biosurfactant production could represent a bacterial adaptive strategy to defend cells from a stress condition derived from heavy metals in the bulk environment.