Serum zinc and copper in people with COVID-19 and zinc supplementation in parenteral nutrition.

OBJECTIVES: Zinc and copper are important to protect cells from oxidative stress and to enhance immunity. An association between low zinc levels and the severity of acute respiratory distress syndrome has been shown for people with COVID-19. We aimed to study serum zinc and copper concentrations in people with severe COVID-19 and zinc supplementation in parenteral nutrition (PN). METHODS: Thirty-five people with COVID-19 in need of PN were studied in a retrospective design. Serum samples were collected at three time points: at the start of PN, between 3 and 7 d after, and at the end of PN. RESULTS: Participants were on PN for a mean of 14 d, with a mean (± SD) daily supplemental zinc of 14.8 ± 3.7 mg/d. Serum zinc increased during PN administration from 98.8 ± 22.8 to 114.1 ± 23.3 µg/dL (Wilks' λ = 0.751, F = 5.459, P = 0.009). Conversely, serum copper did not vary from baseline (107.9 ± 34.2 µg/dL) to the end of the study (104.5 ± 37.4 µg/dL, Wilks' λ = 0.919, F = 1.453, P = 0.248). Serum zinc within the first week after starting PN and at the end of PN inversely correlated with total hospital stay (r = -0.413, P = 0.014, and r = -0.386, P = 0.022, respectively). Participants in critical condition presented lower serum copper (z = 2.615, P = 0.007). Mortality was not associated with supplemental zinc or with serum zinc or copper concentrations at any time of the study (P > 0.1 for all analyses). CONCLUSIONS: Serum zinc concentrations during PN support were inversely associated with length of hospital stay but not with mortality. Serum copper concentrations were lower in participants in critical condition but not associated with prognosis.

Circulating Zinc and Copper Levels are Associated with Sperm Quality in Obese Men after Metabolic Surgery: A Pilot Study.

(1) Background: Inadequate levels of several trace elements and vitamins may impair spermatogenesis in men. Although weight loss after metabolic surgery normalizes male reproductive hormones, sperm quality seems to not improve. We hypothesized that circulating concentrations of zinc, copper and other trace elements and vitamins might be involved. (2) Methods: We studied 20 men submitted to metabolic surgery at baseline and after two years. Hormone profiles, serum trace elements and vitamins were studied together with sperm analysis. (3) Results: At follow-up, serum testosterone, follicle-stimulating hormone and inhibin B concentrations increased showing a beneficial hormonal response for spermatogenesis. Conversely, serum copper, zinc and ferritin showed a decline after surgery. In total, 33% of men showed zinc deficiency, 27% copper deficiency and 20% iron deficiency, among others. Sperm analysis showed that all revaluated patients had at least one abnormal parameter. Serum zinc concentrations showed a positive correlation with progressive motility (r = 0.577, p = 0.031), and serum ferritin a positive correlation with sperm volume (ρ = 0.535, p = 0.049). Serum copper showed a weak and near significant correlation with motility (r = 0.115, p = 0.051). (4) Conclusions: The lack of improvement in sperm quality in obese men after metabolic surgery may be related to nutrient malabsorption, especially zinc, copper and iron.

Alternative Lengthening of Telomeres in the Budding Yeast Naumovozyma castellii.

The enzyme telomerase ensures the integrity of linear chromosomes by maintaining telomere length. As a hallmark of cancer, cell immortalization and unlimited proliferation is gained by reactivation of telomerase. However, a significant fraction of cancer cells instead uses alternative telomere lengthening mechanisms to ensure telomere function, collectively known as Alternative Lengthening of Telomeres (ALT). Although the budding yeast Naumovozyma castellii (Saccharomyces castellii) has a proficient telomerase activity, we demonstrate here that telomeres in N. castellii are efficiently maintained by a novel ALT mechanism after telomerase knockout. Remarkably, telomerase-negative cells proliferate indefinitely without any major growth crisis and display wild-type colony morphology. Moreover, ALT cells maintain linear chromosomes and preserve a wild-type DNA organization at the chromosome termini, including a short stretch of terminal telomeric sequence. Notably, ALT telomeres are elongated by the addition of ∼275 bp repeats containing a short telomeric sequence and the subtelomeric DNA located just internally (TelKO element). Although telomeres may be elongated by several TelKO repeats, no dramatic genome-wide amplification occurs, thus indicating that the repeat addition may be regulated. Intriguingly, a short interstitial telomeric sequence (ITS) functions as the initiation point for the addition of the TelKO element. This implies that N. castellii telomeres are structurally predisposed to efficiently switch to the ALT mechanism as a response to telomerase dysfunction.

Gastrostomy vs nasogastric tube feeding in patients with head and neck cancer during radiotherapy alone or combined chemoradiotherapy

INTRODUCTION: Patients with head and neck cancer (HNC) submitted to radiotherapy alone or combined chemoradiotherapy present a high prevalence of malnutrition at baseline. Prophylactic use of gastrostomy has been suggested for these patients for delivering enteral nutrition. On the other hand, other authors have failed to demonstrate the effectiveness of this measure over nasogastric tube feeding. MATERIAL AND METHODS: We studied 40 patients with HNC with moderate or severe malnutrition who were offered either prophylactic percutaneous gastrostomy before starting oncologic treatment or close follow-up with nutritional counseling with the placement of a nasogastric tube when necessary. RESULTS: There were no significant changes throughout the study period in weight (p = 0.338), body mass index (BMI) (p = 0.314) or serum proteins (p = 0.729), and these changes showed no differences between the gastrostomy vsnasogastric tube feeding groups. The amount of delivered energy was above the estimated energy needs with both gastrostomy and nasogastric tube feeding, but there were no differences in the total energy provided by enteral nutrition between groups. Patients in the gastrostomy group received enteral nutrition support for a longer period of time (p = 0.007). CONCLUSIONS: Both gastrostomy and nasogastric tube feeding are effective methods of delivering enteral nutrition in patients with HNC submitted to radiotherapy alone or combined chemoradiotherapy, with no differences between them in terms of avoiding further nutritional deterioration.

Looking beyond Saccharomyces: the potential of non-conventional yeast species for desirable traits in bioethanol fermentation.

Saccharomyces cerevisiae has been used for millennia in the production of food and beverages and is by far the most studied yeast species. Currently, it is also the most used microorganism in the production of first-generation bioethanol from sugar or starch crops. Second-generation bioethanol, on the other hand, is produced from lignocellulosic feedstocks that are pretreated and hydrolyzed to obtain monomeric sugars, mainly D-glucose, D-xylose and L-arabinose. Recently, S. cerevisiae recombinant strains capable of fermenting pentose sugars have been generated. However, the pretreatment of the biomass results in hydrolysates with high osmolarity and high concentrations of inhibitors. These compounds negatively influence the fermentation process. Therefore, robust strains with high stress tolerance are required. Up to now, more than 2000 yeast species have been described and some of these could provide a solution to these limitations because of their high tolerance to the most predominant stress conditions present in a second-generation bioethanol reactor. In this review, we will summarize what is known about the non-conventional yeast species showing unusual tolerance to these stresses, namely Zygosaccharomyces rouxii (osmotolerance), Kluyveromyces marxianus and Ogataea (Hansenula) polymorpha (thermotolerance), Dekkera bruxellensis (ethanol tolerance), Pichia kudriavzevii (furan derivatives tolerance) and Z. bailii (acetic acid tolerance).

Advances in yeast systematics and phylogeny and their use as predictors of biotechnologically important metabolic pathways.

Detection, identification and classification of yeasts have undergone a major transformation in the last decade and a half following application of gene sequence analyses and genome comparisons. Development of a database (barcode) of easily determined DNA sequences from domains 1 and 2 (D1/D2) of the nuclear large subunit rRNA gene and from ITS now permits many laboratories to identify species quickly and accurately, thus replacing the laborious and often inaccurate phenotypic tests previously used. Phylogenetic analysis of gene sequences is leading to a major revision of yeast systematics that will result in redefinition of nearly all genera. This new understanding of species relationships has prompted a change of rules for naming and classifying yeasts and other fungi, and these new rules are presented in the recently implemented International Code of Nomenclature for algae, fungi, and plants (Melbourne Code). The use of molecular methods for species identification and the impact of Code changes on classification will be discussed, as will use of phylogeny for prediction of biotechnological applications.