Chlorine redox chemistry is not rare in biology

Chlorine is abundant in cells and biomolecules, yet the biology of chlorine oxidation and reduction is poorly understood. Some bacteria encode the enzyme chlorite dismutase (Cld), which detoxifies chlorite (CIO2-) by converting it to chloride (Cl-) and molecular oxygen (O2). Cld is highly specific for chlorite and aside from low hydrogen peroxide activity has no known alternative substrate. Here, we reasoned that because chlorite is an intermediate oxidation state of chlorine, Cld can be used as a biomarker for oxidized chlorine species in microorganisms and microbial habitats. Cld was abundant in metagenomes from soils and freshwater to water treatment systems. About 5% of bacterial and archaeal genera contain an organism encoding Cld in its genome, and within some genera Cld is nearly conserved. Cld has been subjected to extensive horizontal gene transfer, suggesting selection by chlorite is episodic yet strong. Cld was also used as a biomarker to predict genes related to chlorine redox chemistry. Genes found to have a genetic association with Cld include known genes for responding to reactive chlorine species and uncharacterized genes for transporters, regulatory elements, and putative oxidoreductases that present targets for future research. Cld was repeatedly co-located in genomes with genes for enzymes that can inadvertently reduce perchlorate (CIO4-) or chlorate (CIO3-), confirming that in nature (per)chlorate reduction does not only occur in specialized anaerobic respiratory metabolisms. The presence of Cld in genomes of obligate aerobes without such enzymes suggested that chlorite, like hypochlorous acid (HOCl), might be formed by oxidative processes within natural habitats. In summary, the comparative genomics of Cld has provided an atlas for a deeper understanding of chlorine oxidation and reduction reactions that are an underrecognized feature of biology.

Carbonized rice husk as an alternative substrate for Ocimum basilicum L. seedling production

The substrate used in seedling production plays a major role in the initial plant development. In this sense, the objective was to evaluate the emergence capacity and establishment of basil seedlings in different proportions of alternative substrates based on charred rice husk and commercial substrate S10®. The experiment was carried out in expanded polyethylene trays, using basil seeds (Horticeres seeds®), which lasted 28 days. The experimental design was completely randomized, with five treatments (T1: 100 % commercial substrate (BCS); T2: 80 % BCS + 20 % Charred rice husk (CRH); T3: 60 % BCS + 40 % CRH; T4: 40 % BCS + 60 % CRH; T5: 20 % BCS + 80 % CRH) and three repetitions. Were evaluated leaf number, shoot length, root length, root dry mass, shoot dry mass, leaf area, germination, germination speed index, substrate physical analysis (density (dry and wet)), total porosity and aeration space, and chemical analysis (hydrogen potential (PH), and electrical conductivity (EC)). It was observed in the results that the substrate type interferes in the development and quality of the basil seedling. In the shoot lenght parameter, the treatment with 40 % BCS + 60 % CRH (T4) had a significant difference compared to the other treatments. Among the substrates, the best seedling performance was observed in the substrate with 80 % BCS + 20 % CRH (T2), which provided better seedling quality in relation to the other treatments.

Biochar as an alternative substrate for the production of sugarcane seedlings

ABSTRACT Biochar, which has emerged as an important form of the transformation and final disposal of biomass, can be used directly in soil or in seedling nurseries. In this study, the use of biochar of different particle sizes and percentages was evaluated in replacement to a conventional substrate used in the production of sugarcane seedlings. To this end, an experiment was carried out based on a completely randomized design, with a 5 × 4 factorial scheme, consisting of five different percentages of biochar (with 0, 25, 50, 75, and 100% v/v substitution of the conventional substrate) and four particle sizes (<1, 2, 4, and 9 mm), with nine repetitions. As seedling growth variables, the average sprouting time, sprouting speed index, plant height, leaf number, leaf length, and width + 2, as well as the dry mass of the aerial parts and roots were evaluated. Irrespective of the percentage of commercial substrate replaced with biochar, sprouting time was found to be shorter when 6-mm-diameter biochar particles were used. With respect to the sprouting speed index, it was found that regardless of particle size, the highest value occurred when biochar was used to replace 42% of the commercial substrate. The substitution of the commercial substrate with biochar had the effect of reducing the growth of sugarcane seedlings.

Growth of Bacillus toyonensis in Tofu Wastewater

Bacillus toyonensis has been isolated in Dumai mangrove ecosystem of Riau Province. One of factors affecting the growth of the bacteria is growth substrate. Tofu wastewater is rich in nutrition which can be used as substrate for bacterial growth. This research aimed to observe the growth of B. toyonensis in different concentration of tofu wastewater. The bacteria was grown in tofu wastewater at concentrations 8%, 10% and 12% was supplemented with 0.1 g K2HPO4, 0.15 g KH2PO4, 0.15 g NaCl and 0.5 g vitamin B12 in 100 mL distilled water. The bacterial growth was observed by using spectrophotometer at λ 610 nm and by analysis the total plate counts on plate count agar (PCA) at 0, 24, 48, 72 and 96 hour cultivation. Spectrophotometric observation showed that the highest bacterial growth of all tofu wastewater treatments indicated by the addition of 12% tofu wastewater, although the absorbance value was lower than culture in tryptic soy broth (TSB) as control. Exponential growth occurred between 0-24 hour incubation, and the highest growth indicated in substrate contained 12% tofu wastewater. Similarly, total plate count (TPC) analysis indicated that the highest bacterial growth of all treatment occurred at 24 hours incubation, and the highest count was also indicated by treatment of 12% tofu wastewater (2.42±0.06×108 CFU/mL). In conclusion, tofu wastewater can be an alternative substrate for the bacterial growth.

Production of Endoglucanases by Streptomyces thermocoprophilus CP1 using Rice Straw as a Substrate

Rice straw is a major agricultural waste that can be used as an alternative substrate to expensive raw materials for endoglucanases (CMCase) production by microorganisms. This study aimed to search for a microorganism having the potential to produce endoglucanase from rice straw. From compost samples, 40 bacterial colonies were isolated on carboxymethylcellulose (CMC) agar. Among them, 16 isolates showed a hydrolysis zone on a CMC agar plate with hydrolysis (HC) values ranging from 1.15±0.02 to 4.40±0.52. Based on hydrolysis zone diameter and HC value, isolates CP1, CP2 and CP3 were further examined for their CMCase production in CMC broth. According to CMCase production and stability, isolate CP1 was selected for further study. The optimal pH and temperature for CMCase production of isolate CP1 were 5 and 45 °C, respectively. When using pre-treated rice straw as a substrate for semi-solid-state fermentation, the highest CMCase activity of 0.142 ± 0.008 U/mL was obtained in a medium containing pre-treated rice straw of 60 g/L. The sequence alignment analysis and phylogenetic analysis suggested that the isolate CP1 was likely to be Streptomyces thermocoprophilus. The microorganism obtained from this study may be not only industrially important but also beneficial to the environment.

A GID E3 ligase assembly ubiquitinates an Rsp5 E3 adaptor and regulates plasma membrane transporters

Cells rapidly remodel their proteomes to align their cellular metabolism to environmental conditions. Ubiquitin E3 ligases enable this response, by facilitating rapid and reversible changes to protein stability, localization, or interaction partners. In S. cerevisiae, the GID E3 ligase regulates the switch from gluconeogenic to glycolytic conditions through induction and incorporation of the substrate receptor subunit Gid4, which promotes the degradation of gluconeogenic enzymes. Here, we show an alternative substrate receptor, Gid10, which is induced in response to changes in temperature, osmolarity and nutrient availability, and regulates the ART-Rsp5 pathway. Art2 levels are elevated upon GID10 deletion, a crystal structure shows the basis for Gid10-Art2 interactions, and Gid10 directs a GID E3 ligase complex to ubiquitinate Art2. We also find that the GID E3 ligase affects the flux of plasma membrane nutrient transporters during heat stress. The data reveal GID as a system of E3 ligases with metabolic regulatory functions outside of glycolysis and gluconeogenesis, controlled by distinct stress-specific substrate receptors.

ALTERNATIVE SUBSTRATE USE IN SAGE TRANSPLANTS PRODUCTION (SALVIA OFFICINALIS L.)

Mushroom production has become more popular in our environment. The most common cultivated mushroom is Agaricus bisporus. After mushrooms are harvested a large amount of used compost remains. This compost is a good material and producers used it as alternative substrate in plant production. The benefits of this compost are numerous like high content of organic matter and the rich mineral composition. The aim of this study was to determine the effectiveness of the use of spent mushroom compost (as alternative substrate) on growth and development of roots and above-ground parts of sage transplants (Salvia officinalis L.). Measurements of morphological parameters of plants (plant height, number of leaves, number of branches and plant diameter) were performed, as well as determination of fresh and dry weight of roots and above-ground parts of transplants. Application of spent mushroom substrate in the production of sage Salvia officinalis L. positively influenced growth and development as well as fresh and dry weight of roots and above-ground parts of treated plants compared to nontreated plants during transplanting growing stage. Plant height (+104%), number of leaves (+65%), number of branches (+143%), plant diameter (89%), were significantly increased by the spent mushroom compost application compared to the control - commercial substrate.

A Metabolic Intervention for Improving Human Cognitive Performance During Hypoxia

BACKGROUND: During hypoxia an operators cognitive performance may decline. This decline is linked to altered brain metabolism, resulting in decreased adenosine triphosphate (ATP) production. Ketone bodies are an alternative substrate to glucose for brain metabolic requirements; previous studies have shown that the presence of elevated ketone bodies in the blood maintains brain ATP levels and reduces cerebral glycolysis during hypoxia. Thus, ketones may be a strategy to mitigate cognitive decline in hypoxia. Ketone ester (KE) consumption allows rapid elevation of blood ketone levels; therefore, we investigated the effects of consuming a KE drink on cognitive performance during hypoxia. Here, we report results of a pilot study.METHODS: There were 11 subjects who completed a cognitive performance test battery under conditions of normoxia and hypoxia following consumption of a KE drink and a placebo control drink.RESULTS: Significant hypoxia effects (O2 saturation minimum was found to range between 63 and 88 in subjects) were found for blink duration (Ph2 0.665) and blink rate (Ph2 0.626), indicating that the hypoxia condition was associated with longer blink durations and lower blink rates. Significant hypoxia effects were likewise observed for a code substitution task (Ph2 0.487), indicating that performance on the task was significantly disrupted by the hypoxia stressor. KE consumption had a significant effect on blink duration (Ph2 0.270) and the code substitution task (Ph2 0.309).DISCUSSION: These finding suggest that some effects of acute hypoxia can be mitigated by nutritional ketosis.Coleman K, Phillips J, Sciarini M, Stubbs B, Jackson O, Kernagis D. A metabolic intervention for improving human cognitive performance during hypoxia. Aerosp Med Hum Perform. 2021; 92(7):556562.