Oxygen limitation can trigger the production of branched GDGTs in culture

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are ubiquitous and well-preserved sedimentary biomarkers. These compounds serve as important palaeoenvironmental indicators due to strong empirical correlations between brGDGT distributions and temperature and pH in modern environments. However, the mechanistic link between temperature, pH, and brGDGT production has been difficult to study due to uncertainty about the organisms and physiological conditions required for the synthesis of brGDGTs in nature. Here, we report that in the Acidobacterium Edaphobacter aggregans, severe oxygen limitation (1% O2) leads to significant brGDGT production (2.9% of membrane lipids) with three structural varieties including an uncharacterised isomer of brGDGT Ic. Low O2 as a physiological trigger for brGDGT production may help explain why brGDGT producers have been so difficult to identify, and provides a new path towards uncovering the genetic basis and biological function of brGDGTs. If the oxygen effects observed here apply more broadly, the empirical calibrations for brGDGT-based temperature and pH reconstructions may currently be missing the effects of oxygen as a relevant and possibly dominant control in the environmental distributions of brGDGTs.</p

Detailing the Pore Structure of Productive Intervals of Oil Wells Using the Color 3D Imaging

The article describes an approach to expanding the methodology for applying hydraulic fracturing in oil fields by adding the possibilities of 3D modeling with color imaging of the pore structure of the productive intervals of wells. As an applied example, the geological and geophysical section of the productive level of one of the wells of the Moscudinskoye oil field, with known data on the integrated interpretation of the results of well-logging and microcomputer tomography, was chosen. According to well-logging data, the productive reservoir in the analyzed section of the section is characterized by a high degree of heterogeneity. Tomographic studies of a full-size core made it possible to identify four lithotypes here with different pore structure features. Accounting for the identified reservoir heterogeneity, as well as data on the thickness and other characteristics of reservoir properties of individual lithotypes that make up the section, made it possible to significantly increase the detail of the final geological model of the wellbore section. A distinctive feature of this final geological model is the use of the method of enlargement of the initial data array by adding intermediate values that were calculated theoretically. The visibility of the final geological model of the borehole walls is provided by color 3D imaging of the calculated data of the enlarged massif and makes it possible to judge the presence of areas with good and weak fluid conductivity on the lateral surface of the borehole walls. According to this model, intrastratal transverse and longitudinal fluid-conducting “corridors” are observed in the circumwell zone that determine the hydro-dynamic movements of natural and artificial fluids in the space of productive reservoirs

Serine Protease Inhibitor Aprotinin Ameliorates Renal Injury in a Rat Model of Ischemia-Perfusion Injury

Background. Renal ischemia-reperfusion (I/R) injury may occur after renal transplantation, thoracoabdominal aortic surgery, and renal artery interventions

Attenuation of acute lung injury following lower limb ischemia/reperfusion: the pharmacological approach

Aim. The purpose of this study was to examine the effects of N-acetylcysteine (NAC), calcium dobesilate (DOBE) and aprotinin on the amelioration of lung damage following ischemia/reperfusion injury in a rat hind limb model. A well known antioxidant dimethyl-sulfoxide (DMSO) was also tested for comparison

Change in serum CXCL10 levels during anti-tuberculosis treatment depends on vitamin D status

Serum levels of the inflammatory C-X-C motif chemokine 10 (CXCL10) are raised in tuberculosis (TB). CXCL10 gene expression is downregulated in monocytes by metabolically active vitamin D3 (1,25dihydroxy vitamin D). Stratification of patients by serum25hydroxyvitamin D (25[OH]D) levels at baseline showed that treatment-induced decrease in CXCL10 occurred in those with \u27insufficient\u27 and \u27deficient\u27 but not in those with \u27optimal\u27 levels. In the deficient group, 25(OH)D showed an inverse correlation with CXCL10 levels. CXCL10may thus be a useful biomarker for the follow-up of response to treatment. However, CXCL10 levels should be interpreted taking into account the baseline serum vitamin D levels of the TB patients

Rapid and Effective Vitamin D Supplementation May Present Better Clinical Outcomes in COVID-19 (SARS-CoV-2) Patients by Altering Serum INOS1, IL1B, IFNg, Cathelicidin-LL37, and ICAM1

Background: We aimed to establish an acute treatment protocol to increase serum vitamin D, evaluate the effectiveness of vitamin D3 supplementation, and reveal the potential mechanisms in COVID-19. Methods: We retrospectively analyzed the data of 867 COVID-19 cases. Then, a prospective study was conducted, including 23 healthy individuals and 210 cases. A total of 163 cases had vitamin D supplementation, and 95 were followed for 14 days. Clinical outcomes, routine blood biomarkers, serum levels of vitamin D metabolism, and action mechanism-related parameters were evaluated. Results: Our treatment protocol increased the serum 25OHD levels significantly to above 30 ng/mL within two weeks. COVID-19 cases (no comorbidities, no vitamin D treatment, 25OHD < 30 ng/mL) had 1.9-fold increased risk of having hospitalization longer than 8 days compared with the cases with comorbidities and vitamin D treatment. Having vitamin D treatment decreased the mortality rate by 2.14 times. The correlation analysis of specific serum biomarkers with 25OHD indicated that the vitamin D action in COVID-19 might involve regulation of INOS1, IL1B, IFNg, cathelicidin-LL37, and ICAM1. Conclusions: Vitamin D treatment shortened hospital stay and decreased mortality in COVID-19 cases, even in the existence of comorbidities. Vitamin D supplementation is effective on various target parameters; therefore, it is essential for COVID-19 treatment