Oxygen Stress Research Articles

Shedding light on the functional role of the Ignavibacteria in Italian rice field soil: A meta-genomic/transcriptomic analysis

The Ignavibacteria are ubiquitously abundant in paddy soils, but their functional role is poorly known. Here, we applied a targeted meta-genomic/transcriptomic approach to elucidate genetic potential and functional activity of the Ignavibacteria in straw-amended paddy soils from Italy. Eight high-quality metagenome-assembled genomes (MAGs) were recovered, being the largest ones (∅ 4.8 Mbp) among all known Ignavibacteria genomes (∅ 3.7 Mbp). Functional annotation revealed that the Ignavibacteria in Italian paddy soil are facultative anaerobes, represent a novel lineage in the Ignavibacteriae phylum, and have the ability for aerobic-hybrid phenylacetate degradation. Their putative functional roles under anoxic and micro-oxic conditions were assessed by mapping environmental mRNA onto the MAGs. Transcript analysis showed that primary fermentation of sugars to acetate and hydrogen is a major energy-yielding pathway under anoxic conditions. Although the phenylacetate degradation pathway is widely distributed among taxonomically diverse paddy soil bacteria, Ignavibacteria almost exclusively expressed this pathway under micro-oxic conditions. In particular, the transcript level of the paaABCDE gene cluster increased significantly. It encodes a monooxygenase, which is the key enzyme of phenylacetate degradation. This was linked to a significant decrease in transcripts encoding fermentation pathways and oxygen-sensitive hydrogenases, but increase in transcripts encoding TCA cycle, respiratory chain, and proteins involved in oxygen stress response (SOD1, AhpC, Bfr). More than half of the carbohydrate-active enzymes (CAZymes) expressed under anoxic and micro-oxic conditions possessed signal peptides, thereby indicating that Ignavibacteria contribute to the decomposition of complex polymers, such as cellulose, hemicellulose, and chitin. In summary, the Ignavibacteria in rice field soil are metabolically versatile and particularly adapted to the varying oxygen conditions in this ecosystem.

The Stress-Active Cell Division Protein ZapE Alters FtsZ Filament Architecture to Facilitate Division in Escherichia coli.

During pathogenic infections, bacterial cells experience environmental stress conditions, including low oxygen and thermal stress. Bacterial cells proliferate during infection and divide by a mechanism characterized by the assembly of a large cytoskeletal structure at the division site called the Z-ring. The major protein constituting the Z-ring is FtsZ, a tubulin homolog and GTPase that utilizes the nucleotide to assemble into dynamic polymers. In Escherichia coli, many cell division proteins interact with FtsZ and modulate Z-ring assembly, while others direct cell wall insertion and peptidoglycan remodeling. Here, we show that ZapE, an ATPase that accumulates during late constriction, directly interacts with FtsZ and phospholipids in vitro. In the presence of adenosine triphosphate (ATP), ZapE induces bundling of GTP-induced FtsZ polymers; however, ZapE also binds FtsZ in the absence of GTP. The ZapE mutant protein ZapE(K84A), which is defective for ATP hydrolysis, also interacts with FtsZ and induces FtsZ filament bundling. In vivo, cultures of zapE deletion cells contain a low percentage of filamentous cells, suggesting that they have a modest division defect; however, they are able to grow when exposed to stress, such as high temperature and limited oxygen. When combined with the chromosomal deletion of minC, which encodes an FtsZ disassembly factor, ΔzapE ΔminC cells experience growth delays that slow proliferation at high temperature and prevent recovery. This synthetic slow growth phenotype after exposure to stress suggests that ZapE may function to ensure proliferation during and after stress, and this is exacerbated when cells are also deleted for minC. Expression of either ZapE or ZapE(K84A) complements the aberrant growth phenotypes in vivo suggesting that the division-associated role of ZapE does not require ZapE ATP hydrolysis. These results support that ZapE is a stress-regulated cell division protein that interacts directly with FtsZ and phospholipids, promoting growth and division after exposure to environmental stress.

A Reductive Metabolic Switch Protects Infants with Transposition of Great Arteries Undergoing Atrial Septostomy against Oxidative Stress

Transposition of the great arteries (TGA) is one of the most common cyanotic congenital heart diseases requiring neonatal surgical intervention. Parallel circulations that result in impaired cerebral oxygen delivery already in utero may lead to brain damage and long-term neurodevelopmental delay. Balloon atrial septostomy (BAS) is often employed to mix deoxygenated and oxygenated blood at the atrial level. However, BAS causes a sudden increase in arterial blood oxygenation and oxidative stress. We studied changes in oxygen saturation as well as metabolic profiles of plasma samples from nine newborn infants suffering from TGA before and until 48 h after undergoing BAS. The plasma metabolome clearly changed over time and alterations of four metabolic pathways, including the pentose phosphate pathway, were linked to changes in the cerebral tissue oxygen extraction. In contrast, no changes in levels of lipid peroxidation biomarkers over time were observed. These observations suggest that metabolic adaptations buffer the free radical burst triggered by re-oxygenation, thereby avoiding structural damage at the macromolecular level. This study enhances our understanding of the complex response of infants with TGA to changes in oxygenation induced by BAS.

Exercise adaptations and TGF-β1 levels in recreational cyclists

BackgroundCycling is a physical exercise that is widely performed to improve physical fitness. Regular physical exercise will lead to adaptations to exercise. This adaptation is useful in suppressing the production of reactive oxygen stress (ROS) generated in response to cellular metabolism that uses oxygen. Transforming growth factor beta-1 (TGF-β1) plays a role in increasing the production of ROS, thus, when the concentration is low, it would lead to an improvement in physical fitness. This study aims to compare levels of TGF-β1 between recreational cyclists and sedentary groups. In addition, this research also compares several other parameters, which are fasting blood sugar levels and lipid profiles (triglycerides, total cholesterol, HDL cholesterol, and LDL cholesterol) between cyclists and sedentaries. MethodsThis was an observational analytical study with a cross-sectional design. The research subjects consisted of 2 groups, each consisting of 21 participants, namely the recreational cyclist and the sedentary group. Anthropometric examinations were carried out, including body weight, height, body mass index, waist circumference, and body fat percentage. Fasting blood glucose concentration and lipid profile (Triglyceride – TG, Total Cholesterol – Total C, HDL Cholesterol – HDL-C, and LDL Cholesterol – LDL-C) were determined by the enzymatic colorimetric methods, and TGF-β1 levels were determined using the fluorescence of specific antibodies for TGF-β1 (pg/ml) using ELISA method. Statistical analysis was performed using IBM SPSS v. 25. ResultsThe anthropometric variables, other than body height, did not differ significantly between the two groups, so did the fasting blood glucose concentration. Nevertheless, the lipid profile (TG, Total C, HDL-C and LDL-C) were found to be significantly better in the cyclist group (p < 0.05).The mean level of TGF-β1 in recreational cyclists was 8, 908.48 pg/ml, lower than the control group, 10, 229.28 pg/ml. The results of the unpaired t-test showed significant mean differences between the two groups, (p = 0.001; p < 0.05). ConclusionThe levels of TGF-β1 in the recreational cyclist group were lower than the sedentary group. Regular physical exercise will trigger exercise adaptations that can suppress latent TGF-β1 activation.

Neuroprotective effects of arbutin against oxygen and glucose deprivation-induced oxidative stress and neuroinflammation in rat cortical neurons.

In this study, the neuroprotective potential of arbutin (100 µmol L-1) pre-treatment and post-treatment against oxygen/ glucose deprivation (OGD) and reoxygenation (R) induced ischemic injury in cultured rat cortical neurons was explored. The OGD (60 min) and reoxygenation (24 h) treatment significantly (p < 0.001) compromised the antioxidant defence in cultured neurons. Subsequently, an increase (p < 0.001) in lipid peroxidation and inflammatory cytokines (tumour necrosis factor-α and nuclear factor kappa-B) declined neuron survival. In pre- and post-condition experiments, treatment with arbutin enhanced both survival (p < 0.01) and integrity (p < 0.05) of cultured neurons. Results showed that arbutin protects (p < 0.05) against peroxidative changes, inflammation, and enhanced the antioxidant activity (e.g., glutathione, superoxide dismutase and catalase) in cultured neurons subjected to OGD/R. It can be inferred that arbutin could protect against ischemic injuries and stroke. The anti-ischemic activity of arbutin can arrest post-stroke damage to the brain.

Genomic adaptation and metabolic hierarchy: Microbial community response to oxygen stress in community derived from sludge treating refinery wastewater

The complexity of the metabolic networks in a microbial community is decided by the heterogeneity of available carbon sources such as in refinery wastewater treatment plants. The organic loading due to diverse hydrocarbons could be shunted in the metabolic network through different oxygenase's which work on different redox levels. In this study, the three different bioreactors in the continuous mode were set up with different dissolved oxygen (DO) levels with phenol as a representative carbon source. To understand the metabolic diversity, co-assembly from metagenome data was done leading to generation of 27 high-quality genomes which together represent 70% of the community. Clustering at various functional levels along with genomic abundance shows the existence of functional hierarchy in the community. Genomic comparison revealed the various scenarios of genomic adaptation and existence of metabolic plasticity which all together increases the community metabolic capacity. The whole experimental design combined with genome level functional entanglement between community member serve as a method for improvement of wastewater treatment processes under perturbing conditions.

Bioinspiration as a method of problem-based STEM education: A case study with a class structured around the COVID-19 crisis.

Bioinspiration is a promising lens for biology instruction as it allows the instructor to focus on current issues, such as the COVID‐19 pandemic. From social distancing to oxygen stress, organisms have been tackling pandemic‐related problems for millions of years. What can we learn from such diverse adaptations in our own applications? This review uses a seminar course on the COVID‐19 crisis to illustrate bioinspiration as an approach to teaching biology content. At the start of the class, students mind‐mapped the entire problem; this range of subproblems was used to structure the biology content throughout the entire class. Students came to individual classes with a brainstormed list of biological systems that could serve as inspiration for a particular problem (e.g., absorptive leaves in response to the problem of toilet paper shortages). After exploration of relevant biology content, discussion returned to the focal problem. Students dug deeper into the literature in a group project on mask design and biological systems relevant to filtration and transparency. This class structure was an engaging way for students to learn principles from ecology, evolution, behavior, and physiology. Challenges with this course design revolved around the interdisciplinary and creative nature of the structure; for instance, the knowledge of the participants was often stretched by engineering details. While the present class was focused on the COVID‐19 crisis, a course structured through a bioinspired approach can be applied to other focal problems, or subject areas, giving instructors a powerful method to deliver interdisciplinary content in an integrated and inquiry‐driven way.

Genome-wide identification of cassava MeRboh genes and functional analysis in Arabidopsis

Plant respiratory burst oxidase homolog (Rboh) gene family encodes NADPH oxidases, and plays important roles in the production of reactive oxygen species (ROS), plant signaling, growth and stress responses. Cassava is an important starchy crops in tropical region. Environmental stresses, such as drought, pathogen, have caused great yield loss. The mechanisms of stress response are little known in MeRBOH family of cassava. Investigation of Rboh genes response to disease may provide a clue for clarification the disease resistance mechanisms. In this study, eight MeRboh genes were identified from the cassava genome. Comparisons of gene structure, protein motifs, and a phylogenetic tree showed conservation of Rboh gene families in cassava, Arabidopsis and rice. Transcript levels of most MeRboh genes increased following treatment with a pathogen, Xanthomonas axonopodis pv. manihotis, or with phytohormones salicylic acid or jasmonic acid. Analysis of cis-acting elements also indicated that MeRboh genes could response to light, hormone, abiotic and biotic stress. Prediction of miRNA target and post-translation modification sites of MeRboh suggested possible regulations of miRNA and protein phosphorylation; and transient expression of MeRboh in cassava protoplasts confirmed their localization on plasma membrane. Expression of MeRbohB, MeRbohF partially complemented PAMP responses in Arabidopsis rboh mutants, including the expression of PTI marker FRK1, ROS production, peroxide accumulation and callose deposition. It suggesting that MeRbohB and MeRbohF may participate in the PTI pathway and contributed to ROS production triggered by pathogens. Moreover, overexpression of MeRbohB and MeRbohF enhanced the resistance of Arabidopsis against Pseudomonas syringae pv. tomato DC3000. Together, these results suggest the evolutionary conservation of MeRboh gene family and their important role in the immune response and in regulating the plant disease resistance, providing a foundation for revealing molecular mechanisms of cassava disease resistance.

A microsensor‐based method for measuring respiration of individual nematodes

Abstract Meiofauna (invertebrates that pass through a 1‐mm mesh sieve, but are retained on a 40‐µm mesh) represent the most abundant and diverse animal group on Earth, but empirical evidence of their role in benthic respiration, production and carbon cycling across ecosystems is not well documented. Moreover, how meiofauna respond to changing oxygen conditions is poorly understood. We further developed an incubation system, in which oxygen and temperature conditions are easily controlled and single meiofaunal nematode respiration is resolved in glass capillary tubes, using Clark‐type oxygen microsensor. We performed the respiration measurements after exposing nematodes to different ambient oxygen concentrations, which resulted in 3–60 µM O2 during hypoxic and 80–210 µM O2 during oxic incubations in close proximity to the respective nematodes. Individual nematode respiration rates ranged from 0.02 to 1.30 nmol O2 ind.−1 day−1 and were 27% lower during hypoxic than oxic incubations. Rates derived from established allometric relations were on average fourfold higher than our direct measurements. The presented method is suitable for single nematode respiration measurements and can be adapted to a wide range of experimental conditions. Therefore, it can be used to assess meiofauna contribution to ecosystem processes and investigate species‐specific responses to changing environmental conditions, for example, oxygen stress, increasing water temperature.

Dissolved oxygen as a propulsive parameter for polyhydroxyalkanoate production using Bacillus endophyticus cultures

Conventional biopolymers resembling synthetic polymers produced from microorganisms, polyhydroxyalkanoate (PHA) synthesized utilizing renewable resources have gained supreme attention recently. PHA accumulation within the microbial cell is an innate capability of bacteria to store carbon and energy when nutrient imbalance pertains. Gram positive Bacillus endophyticus capable of synthesizing PHA was focused in this study. Study focuses on the possibility of attaining high PHA yield in relation to the varying dissolved oxygen levels induced during production phase. There was a gradual increment in PHA production from 34.5 to 53.03% when cultivated in bioreactor that maintained least dissolved oxygen of 0.4 mg/L at 32 °C. The metabolic flux of organism was altered during oxygen stress brought by varying agitation rate and volume resulting in the accumulation of Nicotinamide Adenine Dinucleotide Hydrogen (NADH), which led to increase in the overall PHA production. PHA yield was found to be favored by decreasing the oxygen supply thereby inducing an oxygen stress environment. This report was the first one that was correlating the hypothesis that links PHA yield and oxygen stress condition during production phase. PHA produced was characterized by FTIR and 1HNMR spectra in which the presence of Polyhydroxybutyrate was confirmed.Graphical abstract

Genome-wide association study reveals multiple novel SNPs and putative candidate genes associated with low oxygen tolerance in golden pompano Trachinotus ovatus (Linnaeus 1758)

Golden pompano (Trachinotus ovatus) is one of the most economically critical marine fishes in South China. Low oxygen stress, which is caused by a variety of factors, has resulted in substantial economic losses to the aquaculture of golden pompano. Genome-wide association study (GWAS) has been widely used to study the genetic basis of important economic traits in aquatic animals. In the present study, 100 individuals were used for genome-wide association study of hypoxia tolerance trait based on genome-wide resequencing technology to explore the SNPs and related candidate genes affecting hypoxia tolerance trait in golden pompano. Four significant SNPs were identified to be suggestively significantly associated with the hypoxia tolerance trait. In the 50 kb window surrounding the suggestive SNPs, 16 potential candidate genes affecting hypoxia tolerance trait were detected. Moreover, validation results of the screened significant loci in the large population were consistent with the results of the GWAS. Among these results, the survival times of individuals with different genotypes at SNP24101852 and SNP24194184 were significantly different (p < 0.01). These results have specific guiding significance for the genetic improvement and determining the molecular mechanism of hypoxia tolerance. These SNPs could be used as molecular markers to screen for hypoxia tolerance be used for further applications in the heritage breeding of golden pompano.

Preparation and characterization of topical solid lipid nanoparticles containing deferoxamine

Introduction: Deferoxamine mesylate increases hypoxia inducible factor-1 alpha transactivation by preventing iron-catalyzed reactive oxygen stress, so it can be used to improve diabetic ulcer healing. This study was undertaken to develop and study physicochemical properties of topical deferoxamine-loaded solid lipid nanoparticles.&#x0D; Method: Solid lipid nanoparticles were prepared using cold homogenization technique and full factorial design to evaluate the effect of surfactant type and amount of lipid. In-vitro characterization of formulations including particle size and distribution, thermal behavior using Differential Scanning Calorimetry, entrapment efficiency, and release profile were carried out.&#x0D; Results: The results showed an acceptable range of particle size (2.88–174 nm), a narrow size distribution, and an average of 60% for drug entrapment efficiency which is significant for a hydrophilic drug. The results from release study showed an initial burst release followed by a slow and prolonged manner. Differential Scanning Calorimetry results also confirmed the results obtained from loading and release evaluations. The best formulation which had a high level of drug loading and the lowest drug release rate contained compritol and oleic acid in the amount of 8% of the total formula, as well as tween 80 and lecithin as a mixture of surfactants.&#x0D; Conclusions: The study demonstrated deferoxamine could be loaded in solid lipid nanoparticles to deliver topically.

Nigerian neonatologists perception and experience with retinopathy of prematurity.

BackgroundRetinopathy of Prematurity (ROP) is an avoidable condition that affects premature infants exposed to oxygen stresses at or soon after birth. In low- and middle-income countries, like Nigeria, neonatal mortality rates are high and very few infants live to develop ROP. With recent better care, ROP is now being diagnosed.ObjectiveThis study aimed to characterize what Nigerian neonatologists understand about ROP.MethodsAt a joint meeting of Nigerian pediatric ophthalmologists and neonatologists in Kebbi State held 26-29 July 2018, questionnaires collected attendees’ perspective and experience with ROP including causes, risk factors and experiences.ResultsFifty-one neonatologists out of 71 returned a completed questionnaire (response rate: 71.8%). The male:female ratio was 1:1.8, and approximately 40% were aged 41-50 years (n=20, 39.22%). Only 3 (6.39%) had experience managing infants below 500g that survived. A majority managed babies with a mean weight of 913g ± 300.37 and age of 27.87 weeks ±2.37. Most had no access to oxygen monitors (n=39,78%). Most had 10 babies to one monitor and used average settings of 90-95%. One third had seen a case of ROP (n=15,29.41%). Only 5.88% (n=3) were unaware of uncontrolled oxygen use as a risk factor. Only 4 (8.89%) had a functional screening team. None were aware of local screening guidelines.ConclusionsRegular educational programs, collaborative clinical presentations and webinars about ROP targeted at the neonatologists and parents, including establishment of screening programs across country will likely help reduce the burden of ROP blindness in Nigeria.

Dynamic changes of antioxidants and fermentative metabolites in apple peel in relation to storage, controlled atmosphere, and initial low oxygen stress

Storage of apples (Malus × domestica, Borkh.) in controlled atmosphere (CA) and/or the application of initial low oxygen stress (ILOS) are very effective in controlling postharvest disorders as bitter pit and superficial scald. This work aims to evaluate the effect of CA-storage and ILOS on the stress-related compounds of apple peel and to deepen the knowledge about the possible role of the antioxidant defense system against postharvest disorders. Fermentative metabolites, ascorbate (ASA), glutathione (GSH), total ascorbate (T-ASA) and total glutathione (T-GSH), ethylene, α-farnesene, conjugated trienols (CTols), as well as standard maturity indices, were monitored on the peel of apples (cv Red Chief) subjected or not to ILOS and stored 120 days in air or CA. CA-storage caused a reduction of conjugated trienols and ethylene production in Red Chief fruit compared to storage in air. ILOS induced an increase in the production of fermentative metabolites, especially when coupled with CA-storage, but the observed increase in ethanol concentration did not affect ethylene production. ILOS pretreatment and CA-storage induced higher T-GSH and GSH content in the peel of Red Chief fruit. In particular, ILOS caused a temporary shift of GSH towards its oxidated form, which finally resulted in an induction of GSH biosynthesis. Given the positive effect of ILOS on the GSH and T-GSH content, we hypothesize that the peel antioxidant compounds might play some role in the protection against postharvest disorders.

Application of Dynamic Controlled Atmosphere Technologies to Reduce Incidence of Physiological Disorders and Maintain Quality of ‘Granny Smith’ Apples

The efficacy of dynamic controlled atmosphere technologies; repeated low oxygen stress (RLOS) and dynamic controlled atmosphere-chlorophyll fluorescence (DCA-CF) to control superficial scald development on ‘Granny Smith’ apples during long-term storage was studied. Fruit were stored for 2, 4, 6, 8, and 10 months at 0 °C in DCA-CF (0.6% O2 and 0.8% CO2), regular atmosphere (RA)(≈21% O2 and 90–95% RH), and RLOS treatments: (1) 0.5% O2 for 10 d followed by ultra-low oxygen (ULO) (0.9% O2 and 0.8% CO2) for 21 d and 0.5% O2 for 7 d or (2) 0.5% O2 for 10 d followed by controlled atmosphere (CA) (1.5% O2 and 1% CO2) for 21 d and 0.5% O2 for 7 d. Development of superficial scald was inhibited for up to 10 months and 7 d shelf life (20 °C) under RLOS + ULO and DCA-CF treatments. Apples stored in RLOS + ULO, RLOS + CA, and DCA-CF had significantly (p &lt; 0.05) higher flesh firmness and total soluble solids. The RLOS phases applied with CA or ULO and DCA-CF storage reduced the development of superficial scald by possibly suppressing the oxidation of volatiles implicated in superficial scald development.

In-situ expressions of comammox Nitrospira along the Yangtze River

The recent discovery of comammox Nitrospira as complete nitrifiers has significantly enriched our understanding on the nitrogen cycle, yet little is known about their metabolic transcripts in natural aquatic ecosystems. Using the genome-centric metatranscriptomics, we provided the first in-situ expression patterns of comammox Nitrospira along the Yangtze River. Our study confirmed widespread expressions of comammox Nitrospira, with the highest transcription accounting for 33.3% and 63.8% of amoA and nxrAB genes expressed in ammonia-oxidizing prokaryotes (AOPs) and Nitrospira sublineages I/II, respectively. Moreover, comammox two clades differed in nitrification, with clade A acting as the dominator to ammonia oxidation in comammox, and clade B contributing more transcripts to nitrite oxidation than to ammonia oxidation. Compared to canonical Nitrospira, comammox community had lower expressions of ammonia/nitrite transporters and nitrogen assimilatory genes, but far higher expressions in urea transport and hydrolysis, facilitating to derivation of ammonia and energy mainly through intracellular ureolytic metabolism. This suggests no need for “reciprocal-feeding” between canonical Nitrospira and AOPs in a natural river. Aerobic mixotrophy of comammox bacteria was suggested by expressions of genes coding for respiratory complexes I-V, oxidative/reductive TCA cycle, oxygen stress defenses, and transport/catabolism of simple carbohydrates and low-biosynthetic-cost amino acids. Intriguingly, significant positive correlations among expressions of ammonia monooxygenases, hydroxylamine dehydrogenase and copper-dependent nitrite reductase indicated that comammox Nitrospira had the potential of converting nitrite to nitric oxide accompanied by ammonia oxidation under low-C/N and aerobic conditions, while gene expressions in this pathway were significantly and positively associated with pH. Overall, this study illustrated novel transcriptional characteristics of comammox Nitrospira, and highlighted the necessity of reassessing their contributions to biogeochemical carbon and nitrogen cycling with perspective of in-situ meta-omics as well as culture experiments.

Upregulation of Chemoresistance by Mg2+ Deficiency through Elevation of ATP Binding Cassette Subfamily B Member 1 Expression in Human Lung Adenocarcinoma A549 Cells.

Several anticancer drugs including cisplatin (CDDP) induce hypomagnesemia. However, it remains fully uncertain whether Mg2+ deficiency affects chemosensitivity of cancer cells. Here, we investigated the effect of low Mg2+ concentration (LM) on proliferation and chemosensitivity using human lung adenocarcinoma A549 cells. Cell proliferation was reduced by continuous culture with LM accompanied with the elevation of G1 phase proportion. The amounts of reactive oxygen species (ROS) and stress makers such as phosphorylated-ataxia telangiectasia mutated and phosphorylated-p53 were increased by LM. Cell injury was dose-dependently increased by anticancer drugs such as CDDP and doxorubicin (DXR), which were suppressed by LM. Similar results were obtained by roscovitine, a cell cycle inhibitor. These results suggest that LM induces chemoresistance mediated by ROS production and G1 arrest. The mRNA and protein levels of ATP binding cassette subfamily B member 1 (ABCB1) were increased by LM and roscovitine. The LM-induced elevation of ABCB1 and nuclear p38 expression was suppressed by SB203580, a p38 MAPK inhibitor. PSC833, an ABCB1 inhibitor, and SB203580 rescued the sensitivity to anticancer drugs. In addition, cancer stemness properties were suppressed by SB203580. We suggest that Mg2+ deficiency reduces the chemotherapy sensitivity of A549 cells, although it suppresses cell proliferation.

African Americans and European Americans exhibit distinct gene expression patterns across tissues and tumors associated with immunologic functions and environmental exposures

The COVID-19 pandemic has affected African American populations disproportionately with respect to prevalence, and mortality. Expression profiles represent snapshots of combined genetic, socio-environmental (including socioeconomic and environmental factors), and physiological effects on the molecular phenotype. As such, they have potential to improve biological understanding of differences among populations, and provide therapeutic biomarkers and environmental mitigation strategies. Here, we undertook a large-scale assessment of patterns of gene expression between African Americans and European Americans, mining RNA-Seq data from 25 non-diseased and diseased (tumor) tissue-types. We observed the widespread enrichment of pathways implicated in COVID-19 and integral to inflammation and reactive oxygen stress. Chemokine CCL3L3 expression is up-regulated in African Americans. GSTM1, encoding a glutathione S-transferase that metabolizes reactive oxygen species and xenobiotics, is upregulated. The little-studied F8A2 gene is up to 40-fold more highly expressed in African Americans; F8A2 encodes HAP40 protein, which mediates endosome movement, potentially altering the cellular response to SARS-CoV-2. African American expression signatures, superimposed on single cell-RNA reference data, reveal increased number or activity of esophageal glandular cells and lung ACE2-positive basal keratinocytes. Our findings establish basal prognostic signatures that can be used to refine approaches to minimize risk of severe infection and improve precision treatment of COVID-19 for African Americans. To enable dissection of causes of divergent molecular phenotypes, we advocate routine inclusion of metadata on genomic and socio-environmental factors for human RNA-sequencing studies.

Aquaporin family lactic acid channel NIP2;1 promotes plant survival under low oxygen stress in Arabidopsis.

Under anaerobic stress, Arabidopsis thaliana induces the expression of a collection of core hypoxia genes that encode proteins for an adaptive response. Among these genes is NIP2;1, which encodes a member of the "Nodulin 26-like Intrinsic Protein" (NIP) subgroup of the aquaporin superfamily of membrane channel proteins. NIP2;1 expression is limited to the "anoxia core" region of the root stele under normal growth conditions, but shows substantial induction (up to 1,000-fold by 2-4 h of hypoxia) by low oxygen stress, and accumulation in all root tissues. During hypoxia, NIP2;1-GFP accumulates predominantly on the plasma membrane by 2 h, is distributed between the plasma and internal membranes during sustained hypoxia, and remains elevated in root tissues through 4 h of reoxygenation recovery. In response to hypoxia challenge, T-DNA insertion mutant nip2;1 plants exhibit elevated lactic acid within root tissues, reduced efflux of lactic acid, and reduced acidification of the external medium compared to wild-type plants. Previous biochemical evidence demonstrates that NIP2;1 has lactic acid channel activity, and our work supports the hypothesis that NIP2;1 prevents lactic acid toxicity by facilitating release of cellular lactic acid from the cytosol to the apoplast, supporting eventual efflux to the rhizosphere. In evidence, nip2;1 plants demonstrate poorer survival during argon-induced hypoxia stress. Expressions of the ethanolic fermentation transcript Alcohol Dehydrogenase1 and the core hypoxia-induced transcript Alanine Aminotransferase1 are elevated in nip2;1, and expression of the Glycolate Oxidase3 transcript is reduced, suggesting NIP2;1 lactic acid efflux regulates other pyruvate and lactate metabolism pathways.

Pengaruh Padat Tebar terhadap Konsumsi Oksigen dan Respons Stres Ikan Cupang Alam (Betta imbellis)

&lt;strong&gt;Effect of Stocking Density on Oxygen Consumption and Stress Response in Crescent Betta (&lt;em&gt;Betta imbellis&lt;/em&gt;)&lt;/strong&gt;. Stocking density is one of the determinant parameters for fish growth optimization in aquaculture systems due to its relationship with fish metabolism. Information about the impact of different stocking densities on crescent betta (&lt;em&gt;Betta imbellis&lt;/em&gt;) metabolism was not available yet. This study was aimed to analyze the effect of stocking density on oxygen consumption, critical oxygen level, and stress responses in crescent betta.The study was carried out under three different stocking density treatments: 5, 10, and 15 fish/L with three replications using 2.74 ± 0.23 cm total length and 0.22 ± 0.05 g body weight tested fishes.The parameters observed were oxygen consumption, ventilation rate, blood glucose level, cortisol, and critical oxygen level. The result showed that the highest oxygen consumption was found at 5 fish/L stocking density treatment (3.01 ± 0.28 mg O&lt;sub&gt;2&lt;/sub&gt;/g/h), which was significantly different from 10 fish/L (1.01 ± 0.21 mg O&lt;sub&gt;2&lt;/sub&gt;/g/h) and 15 fish/L (0.92 ± 0.08 mg O&lt;sub&gt;2&lt;/sub&gt;/g/h) stocking density treatments. Oxygen consumptions under hypoxic condition was not significantly different compared to normoxic condition.The ventilation rate tends to increase significantly along with the increasing of stocking densities. Critical oxygen levels were not significantly different among the treatments,with the value of 3.31 ± 0.65 mg/L, 3.14 ± 0.29 mg/L, and 2.83 ± 0.19 mg/L for stocking density of 5, 10, and 15 fish/L, respectively. The blood glucose level at 15 fish/L stocking density was significantly higher than others, whereas the cortisol levels was not significantly different among the treatments. The results of this study provided information that the increasing stocking density of cressent betta will decrease their metabolism activity and increase ventilation rate. However, the increase of ventilation rate was negatively correlated with oxygen consumption per breath at higher stocking densities due to decrease in fish activity; and higher stocking densities will decrease oxygen consumption. Based on the results, it can be concluded that the ideal stocking density for crescent betta is 5 fish/L. The increasing of stocking density will decrease oxygen consumption rates and increase the stress level of crescent betta.