Selenium is an essential microelement required for a number of biological functions. Selenium—and more specifically the amino acid selenocysteine—is present in at least 25 human selenoproteins involved in a wide variety of essential biological functions, ranging from the regulation of reactive oxygen species (ROS) concentration to the biosynthesis of hormones. These processes also play a central role in preventing and modulating the clinical outcome of several diseases, including cancer, diabetes, Alzheimer’s disease, mental disorders, cardiovascular disorders, fertility impairments, inflammation, and infections (including SARS-CoV-2). Over the past years, a number of studies focusing on the relationship between selenium and such pathologies have been reported. Generally, an adequate selenium nutritional state—and in some cases selenium supplementation—have been related to improved prognostic outcome and reduced risk of developing several diseases. On the other hand, supra-nutritional levels might have adverse effects. The results of recent studies focusing on these topics are summarized and discussed in this review, with particular emphasis on advances achieved in the last decade.

A series of benzenesulfonamides bearing selenourea moieties was obtained considering the ureido-sulfonamide , in Phase I clinical trials as antitumor agent, as a lead molecule. All compounds showed interesting inhibition potencies against the physiologically relevant human (h) carbonic anhydrase (hCAs, EC 4.2.1.1) isoforms I, II, IV, and IX. The most flexible analogues in the series- showed low nanomolar inhibition constants against hCA I, II, and IX. We assessed selected compounds on the antioxidant properties and binding modes and evaluated human prostate (PC3), breast (MDA-MB-231), and colon-rectal (HT-29) cancer cell lines both in normoxic and hypoxic conditions.

Aryl selenols effectively inhibit carbonic anhydrase.

The underwater tubular photobioreactor is a fully controlled outdoor system to study photosynthetic bacteria. Before growing bacteria cells outdoors, two modified van Niel medium (vN-A, vN-B) were tested under artificial light. During exponential growth, the specific growth rates were 0.0416 and 0.0434 h(-1), respectively; vN-B was chosen for outdoor experiments. The growth behavior of Rhodopseudomonas palustris was investigated under a natural light-dark cycle (sunrise-sunset, 15L/9D) and a forced light-dark cycle (9:00-19:00, 10L/14D). Relationships between solar radiations, daily growth rates, and biomass output rates were also investigated. After determining the elemental biomass molar composition and its combustion heat, some trends of photosynthetic efficiency (PE) were obtained over daylight. The PE trends were always of the oscillatory type, with the exception of that achieved at low biomass concentration. Under a natural light/dark cycle, the maximum PE (11.2%) was attained at sunset, while under a forced light/dark cycle, the highest PE (8.5%) was achieved in the morning. Three initial biomass concentrations were investigated (0.65, 1.01, and 1.54 g l(-1)). The stoichiometric equation for bacteria cells indicated that 87.7% of the carbon of acetic acid was converted to biomass and only 12.3% was lost as CO(2).

Treatment of epoxides with bis(trimethylsilyl)-selenide under strictly controlled conditions allows to isolate b-hydroxy selenols which evidence an unexpected stability, taking into account their known propensity to afford diselenides. Also thiiranes and aziridines lead to functionalized selenols bearing a thiol and a N-Ts-or N-Boc-protected amino moiety on b-position. These selenols were stable enough to react with different electrophiles. Ab-initio DF calculations on two suitable model systems, n-propyl selenol and bhydroxy derivative, allow to ascribe the observed low tendency to oxidation to noncovalent interactions between the selenol moiety and the ÀOH group.