Histidine substitution in the most flexible fragments of firefly luciferase modifies its thermal stability.

Molecular dynamics (MD) at two temperatures of 300 and 340 K identified two histidine residues, His461 and His489, in the most flexible regions of firefly luciferase, a light emitting enzyme. We therefore designed four protein mutants H461D, H489K, H489D and H489M to investigate their enzyme kinetic and thermodynamic stability changes. Substitution of His461 by aspartate (H461D) decreased ATP binding affinity, reduced the melting temperature of protein by around 25 degrees C and shifted its optimum temperature of activity to 10 degrees C. In line with the common feature of psychrophilic enzymes, the MD data showed that the overall flexibility of H461D was relatively high at low temperature, probably due to a decrease in the number of salt bridges around the mutation site. On the other hand, substitution of His489 by aspartate (H489D) introduced a new salt bridge between the C-terminal and N-terminal domains and increased protein rigidity but only slightly improved its thermal stability. Similar changes were observed for H489K and, to a lesser degree, H489M mutations. Based on our results we conclude that the MD simulation-based rational substitution of histidines by salt-bridge forming residues can modulate conformational dynamics in luciferase and shift its optimal temperature activity

The action of physiological and synthetic steroids on the calcium channel CatSper in human sperm

The sperm-specific channel CatSper (cation channel of sperm) controls the intracellular Ca2+ concentration ([Ca2+]i) and plays an essential role in sperm function. It is mainly activated by the steroid progesterone (P4) but is also promiscuously activated by a wide range of synthetic and physiological compounds. These compounds include diverse steroids whose action on the channel is so far still controversial. To investigate the effect of these compounds on CatSper and sperm function, we developed a high-throughput screening (HTS) assay to measure changes in [Ca2+]i in human sperm and screened 1,280 approved and off-patent drugs including 90 steroids from the Prestwick chemical library. More than half of the steroids tested (53%) induced an increase in [Ca2+]i and reduced the P4-induced Ca2+ influx in human sperm in a dose-dependent manner. Ten of the most potent steroids (activating and P4-inhibiting) were selected for a detailed analysis of their action on CatSper and their ability to act on sperm acrosome reaction (AR) and penetration in viscous media. We found that these steroids show an inhibitory effect on P4 but not on prostaglandin E1-induced CatSper activation, suggesting that they compete for the same binding site as P4. Pregnenolone, dydrogesterone, epiandrosterone, nandrolone, and dehydroepiandrosterone acetate (DHEA) were found to activate CatSper at physiologically relevant concentrations within the nanomolar range. Like P4, most tested steroids did not significantly affect the AR while stanozolol and estropipate slightly increased sperm penetration into viscous medium. Furthermore, using a hybrid approach integrating pharmacophore analysis and statistical modelling, we were able to screen in silico for steroids that can activate the channel and define the physicochemical and structural properties required for a steroid to exhibit agonist activity against CatSper. Overall, our results indicate that not only physiological but also synthetic steroids can modulate the activity of CatSper with varying potency and if bound to CatSper prior to P4, could impair the timely CatSper activation necessary for proper fertilization to occur

Aging Skin: Nourishing from Out-In. Lessons from Wound Healing

Skin lesion therapy, peculiarly in the elderly, cannot be isolated from understanding that the skin is an important organ consisting of different tissues. Furthermore, dermis health is fundamental for epidermis integrity, and so adequate nourishment is mandatory in maintaining skin integrity. The dermis nourishes the epidermis, and a healthy epidermis protects the dermis from the environment, so nourishing the dermis through the epidermal barrier is a technical problem yet to be resolved. This is also a consequence of the laws and regulations restricting cosmetics, which cannot have properties that pass the epidermal layer. There is higher investment in cosmetics than in the pharmaceutical industry dealing with skin therapies, because the costs of drug registration are enormous and the field is unprofitable. Still, wound healing may be seen as an opportunity to “feed” the dermis directly. It could also verify whether providing substrates could promote efficient healing and test optimal skin integrity maintenance, if not skin rejuvenation, in an ever aging population

Chemical composition and insecticidal activity of essential oil from Ziziphora clinopodioides Lam. used against the Mediterranean flour moth, Ephestia kuehniella Zeller

The Mediterranean flour moth, Ephestia kuehniella Zeller, is a major pest of stored grain products, particularly flour. There have been major concerns over the application of conventional insecticides in stored products, which have strongly demonstrated the need for applying such alternative safe compounds as essential oils. The aim of the present study is to investigate the chemical composition and fumigant toxicity of essential oil from Ziziphora clinopodioides Lam. against the eggs, larvae, and adults of E. kuehniella. All toxicity tests were carried out under laboratory conditions set at 26±1°C and 70% relative humidity (RH). The results of gas chromatography- -mass spectrometry (GC/MS) analysis indicated that the essential oil extracted from the leaves of Z. clinopodioides, is rich in pulegone (49.4%), piperitenone (10.7%), menthone (8.9%), and 1,8-cineol (6.9%). Based on the bioassay results, the LC50 value of the tested oil was estimated to be 54.61 μl · l–1 air for larvae and 1.39 μl · l–1 air for adults. Also, it is shown that increasing the oil concentration resulted in a significant increase in oviposition deterrency as well as a considerable reduction in the egg hatching percentage. These results suggest that Z. clinopodioides oil could be a potential candidate as a fumigant for managing E. kuehniella in stored products

Dysregulation of microRNAs regulating survivin in CD4+ T cells in multiple sclerosis

Background: Impaired elimination mechanisms of the autoreactive lymphocytes, like T lymphocytes, via apoptosis may be the cause of continues inflammatory state in multiple sclerosis (MS). BIRC5 gene codify for the survivin, which participates in the modulation of apoptosis and cell survival. The objective of this study was investigation of the role of important confirmed miRNAs, including miR-335, miR-485, miR-542, and miR-708, in the regulation of survivin mRNA in the CD4+ T cells of MS cases. Methods: In this study, 50 RRMS patients as well as 50 healthy matched controls were recruited. The peripheral blood mononuclear cells (PBMCs) were isolated from whole blood samples and CD4+ T cells were prepared. After that, RNA was extracted, cDNA was synthesized, and the expression levels of miR-335, miR-485, miR-542, and miR-708 were measured using Real-time PCR. Moreover, the mRNA expression of survivin was detected. Serum level of survivin was detected using ELISA. Results: The mRNA of survivin was 2-folds upregulated in the CD4+ T cells from MS patients in comparison to the healthy controls (P = 0.0053). Serum level of survivin was higher in patients than controls. There was statistically significant downregulation of miR-485 (P = 0.001) and miR-708 (P = 0.011) in CD4+ T cells of patients compared with controls. The miR-485 downregulation had statistically significant correlation with the mRNA expression and serum level of survivin. Conclusion: miRNAs play a role in the regulation of survivin, and therefore apoptosis of CD4+ T cells, and hence are probably participating in a persistent inflammatory condition in MS patients. © 2020 Elsevier B.V

Maternal occupational exposure to endocrine-disrupting chemicals during pregnancy and semen parameters in adulthood: results of a nationwide cross-sectional study among Swiss conscripts

International audienceSTUDY QUESTION: Is there a relationship between maternal occupational exposure to endocrine-disrupting chemicals (EDCs) during pregnancy and the semen quality of their sons? SUMMARY ANSWER: Our results suggest an association between maternal occupational exposure to potential EDCs, especially to pesticides, phthalates and heavy metals, and a decrease in several semen parameters. WHAT IS KNOWN ALREADY: Sexual differentiation, development and proper functioning of the reproductive system are largely dependent on steroid hormones. Although there is some animal evidence, studies on maternal exposure to EDCs during pregnancy and its effect on the semen quality of sons are scarce and none have focused on maternal occupational exposure. STUDY DESIGN, SIZE, DURATION: A cross-sectional study aiming to evaluate semen quality was carried out among Swiss conscripts aged 18 to 22 years between 2005 and 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: Conscript and parent questionnaires were completed prior to the collection of a semen sample. Semen parameters were categorised according to the guidelines of the World Health Organization (WHO). Data on maternal employment during pregnancy were provided by the parent questionnaire. Maternal occupational exposure to potential EDC categories was defined using a job-exposure matrix (JEM). Logistic regressions were used to analyse the relationship between maternal occupational exposure to EDCs and each semen parameter adjusted for potential confounding factors. Results are presented using odds ratios and 95% confidence intervals. MAIN RESULTS AND THE ROLE OF CHANCE: In total, 1,737 conscripts provided a conscript and parent questionnaire, as well as a semen sample; among these 1,045 of their mothers worked during pregnancy. Our study suggests an association between occupational exposure of mothers during pregnancy to potential EDCs and low semen volume and total sperm count, particularly for exposure to pesticides (OR 2.07, 95% CI 1.11-3.86 and OR 2.14, 95% CI 1.05-4.35), phthalates (OR 1.92, 95% CI 1.10-3.37 and OR 1.89, 95% CI 1.01-3.55), and heavy metals (OR 2.02, 95% CI 1.14-3.60 and OR 2.29, 95% CI 1.21-4.35). Maternal occupational exposure to heavy metals was additionally associated with a low sperm concentration (OR 1.89, 95% CI 1.06-3.37). LIMITATIONS, REASONS FOR CAUTION: Several limitations should be noted, such as the indirect method for maternal occupational exposure assessment during the pregnancy (JEM) and the cross-sectional design of the study. WIDER IMPLICATIONS OF THE FINDINGS: Our observations reinforce the need to inform pregnant women of potential hazards during pregnancy that could impair their child’s fertility. Additional studies are needed to confirm the involvement of EDCs. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Swiss Centre for Applied Human Toxicology: SCAHT and the ’Fondation privée des Hôpitaux Universitaires de Genève’. The collection of human biological material used for this study was supported by the FABER Foundation, the Swiss National Science Foundation (SNSF): NFP 50 ’Endocrine Disruptors: Relevance to Humans, Animals and Ecosystems’, the Medical Services of the Swiss Army (DDPS) and Medisupport. The authors declare they have no competing financial interests. TRIAL REGISTRATION NUMBER: N/A

Preclinical Alterations in Myocardial Microstructure in People with Metabolic Syndrome

Objective: Metabolic syndrome (MetS) can lead to myocardial fibrosis, diastolic dysfunction and eventual heart failure. We evaluated alterations in myocardial microstructure in people with MetS using a novel algorithm to characterize ultrasonic signal intensity variation. Methods: Among 254 participants without existing cardiovascular disease (mean age 42 ± 11 years, 75% women), there were 162 with MetS, 47 with obesity without MetS, and 45 non-obese controls. Standard echocardiography was performed, and a novel validated computational algorithm was used to investigate myocardial microstructure based on sonographic signal intensity and distribution. We examined the signal intensity coefficient (SIC, left ventricular microstructure). Results: The SIC was significantly higher in people with MetS compared with people with (P<0.001) and without obesity (P=0.04), even after adjustment for age, sex, body mass index, hypertension, diabetes mellitus and triglyceride to HDL cholesterol (TG/HDL) ratio (P<0.05 for all). Clinical correlates of SIC included TG concentrations (r=0.21, P=0.0007) and the TG/HDL ratio (r=0.2, P=0.001). Conclusions: Our findings suggest that preclinical MetS and dyslipidemia in particular, are associated with altered myocardial signal intensity variation. Future studies are needed to determine whether the SIC may help detect subclinical disease in people with metabolic disease, with the ultimate goal of targeting preventive efforts

Semen quality of young men in Switzerland: a nationwide cross‐sectional population‐based study

International audienceBackgroundSperm counts have been steadily decreasing over the past five decades with regional differences in the Western world. The reasons behind these trends are complex, but numerous insights indicate that environmental and lifestyle factors are important players.ObjectiveTo evaluate semen quality and male reproductive health in Switzerland.Materials and methodsA nationwide cross‐sectional study was conducted on 2523 young men coming from all regions of Switzerland, recruited during military conscription. Semen volume, sperm concentration, motility, and morphology were analyzed. Anatomy of the genital area and testicular volume was recorded. Testicular cancer incidence rates in the general population were retrieved from Swiss regional registries.ResultsMedian sperm concentration adjusted for period of sexual abstinence was 48 million/mL. Comparing with the 5th percentile of the WHO reference values for fertile men, 17% of men had sperm concentration below 15 million/mL, 25% had less than 40% motile spermatozoa, and 43% had less than 4% normal forms. Disparities in semen quality among geographic regions, urbanization rates, and linguistic areas were limited. A larger proportion of men with poor semen quality had been exposed in utero to maternal smoking. Furthermore, testicular cancer incidence rates in the Swiss general population increased significantly between 1980 and 2014.DiscussionFor the first time, a systematic sampling among young men has confirmed that semen quality is affected on a national level. The median sperm concentration measured is among the lowest observed in Europe. No specific geographical differences could be identified. Further studies are needed to determine to what extent the fertility of Swiss men is compromised and to evaluate the impact of environmental and lifestyle factors.ConclusionA significant proportion of Swiss young men display suboptimal semen quality with only 38% having sperm concentration, motility, and morphology values that met WHO semen reference criteria