Evidence of streamlined extracellular electron transfer pathway from biofilm structure, metabolic stratification, and long-range electron transfer parameters.

A strain of Geobacter sulfurreducens , an organism capable of respiring solid extracellular substrates, lacking four out of five outer membrane cytochrome complexes (strain extABCD + ) grows faster and produces greater current density compared to wild type grown under identical conditions. To understand cellular and biofilm modifications altered in extABCD + responsible for this increased performance, biofilms grown using electrodes as terminal electron acceptors were sectioned and imaged using electron microscopy to determine changes in thickness and cell density, while parallel biofilms incubated in the presence of nitrogen and carbon isotopes were analyzed using NanoSIMS to quantify and localize anabolic activity. Long-distance electron transfer parameters were measured for wild type and extABCD + biofilms spanning 5 μm gaps. Our results reveal that extABCD + biofilms achieved higher current densities through the additive effects of denser cell packing close to the electrode (based on electron microscopy), combined with higher metabolic rates per cell compared to wild type (based on increased rates of 15 N incorporation). We also observed an increased rate of electron transfer through extABCD + vs. wild-type biofilms, suggesting that denser biofilms resulting from the deletion of unnecessary multi-heme cytochromes streamlines electron transfer to electrodes. The combination of imaging, physiological and electrochemical data confirms that engineered electrogenic bacteria are capable of producing more current per cell and, in combination with higher biofilm density and electron diffusion rates, can produce a higher final current density than wild type. Importance Current-producing biofilms in microbial electrochemical systems could potentially sustain technologies ranging from wastewater treatment to bioproduction of electricity if the maximum current produced could be increased and current production start-up times after inoculation could be reduced. Enhancing the current output of microbial electrochemical systems has been mostly approached by engineering physical components of reactors and electrodes. Here, we show that biofilms formed by a Geobacter sulfurreducens strain producing ∼1.4x higher current compared to wild type results from a combination of denser cell packing and higher anabolic activity, enabled by an increased rate of electron diffusion through the biofilms. Our results confirm that it is possible to engineer electrode-specific G. sulfurreducens strains with both faster growth on electrodes and streamlined electron transfer pathways for enhanced current production.

Study of anabolic activity of dry extracts of leaves and rhizomes of Iris hungarica on a model of hydrocortisone-induced protein catabolism

This article presents the results of the study of the anabolic effect of dry extracts of Iris hungarica leaves and rhizomes on the model of hydrocortisoneinduced protein catabolism. Previous studies have established the presence of anabolic activity of dry extracts of Iris hungarica leaves and rhizomes in intact animals. Therefore, it was reasonable to study the effect of the experimental extracts on the state of protein metabolism, which is regulated by glucocorticoids. The model of hydrocortisoneinduced protein catabolism was used to determine anabolic activity for dry extracts of Iris hungarica leaves and rhizomes at a dose of 150 mg/kg by monitoring the recovery of body weight and the increase in the total protein in the cardiac muscle of rats and in muscle tissue homogenate, which is aimed to promote myofibrillar hypertrophy. Dry extract of Iris hungarica rhizomes reduced urea excretion, normalized metabolism, restored nitrogen balance, and inhibited protein catabolism. The results indicate that dry extract of Iris hungarica has the ability to correct protein metabolism, which is regulated in part by glucocorticoids, due to the high content of isoflavonoids and amino acids, and suggest that there is a potential use for this herbal product in the development of a new drug aimed at correcting protein metabolism and muscular atrophy.

EXPERIMENTAL EVALUATION OF SOURCE PLANTS OF DUGDHIKA (EUPHORBIA HIRTA LINN. AND EUPHORBIA THYMIFOLIA LINN.) FOR ANABOLIC ACTIVITY: AN IN VIVO STUDY

Rajakshavaka a drug, mentioned in Brimhaniya Maha Kashaya Gana of Charaka is mentioned as Dugdhika by Chakrapani in his commentary and in Bhava Prakasha KC Chunekar commentary, 4 sources are mentioned for the same. Among 4 sources only 2 sources are locally available i.e., Euphorbia hirta Linn and Euphorbia thymifolia Linn. These 2 sources were selected to evaluate Brimhana (Anabolic) action experimentally to understand the better source plant for Dugdhika among locally available sources. The objective of the Study is to experimentally evaluate the drug Dugdhika (Europhobia hirta Linn. Europhobia thymifolia Linn) with respect to its anabolic activity. Anabolic activity was estimated in Wistar rats by administering Hydro-alcoholic extract of Euphorbia hirta Linn (HAEEH) and Euphorbia thymifolia Linn (HAEET) with Normal and High Protein Diet (HPD: Protein – 39.4%, Fat – 10.0%, Fibre – 4.3%, Carbohydrates - 7.0 %). Anabolism was evidenced by physical parameters (Weight, Nose to Anus length, Chest Circumference, Abdominal circumference, BMI), Lean body mass (LBM), Fat body mass (FBM) and Biochemical and Haematological parameters. Both the sources of Dugdhika (Euphorbia hirta Linn and Euphorbia thymifolia Linn) showed significant anabolic action. But, among the two sources Euphorbia thymifolia Linn was more significant compared to Euphorbia hirta Linn with HPD. The obtained results revealed that, among the two locally available sources of Dugdhika (Euphorbia hirta Linn and Euphorbia thymifolia Linn) Euphorbia thymifolia Linn is a better source plant for Brimhana action.

Development of cyclic peptides with potent in vivo osteogenic activity through RaPID-based affinity maturation

Osteoporosis is caused by a disequilibrium between bone resorption and bone formation. Therapeutics for osteoporosis can be divided into antiresorptives that suppress bone resorption and anabolics which increase bone formation. Currently, the only anabolic treatment options are parathyroid hormone mimetics or an anti-sclerostin monoclonal antibody. With the current global increases in demographics at risk for osteoporosis, development of therapeutics that elicit anabolic activity through alternative mechanisms is imperative. Blockade of the PlexinB1 and Semaphorin4D interaction on osteoblasts has been shown to be a promising mechanism to increase bone formation. Here we report the discovery of cyclic peptides by a novel RaPID (Random nonstandard Peptides Integrated Discovery) system-based affinity maturation methodology that generated the peptide PB1m6A9 which binds with high affinity to both human and mouse PlexinB1. The chemically dimerized peptide, PB1d6A9, showed potent inhibition of PlexinB1 signaling in mouse primary osteoblast cultures, resulting in significant enhancement of bone formation even compared to non-Semaphorin4D–treated controls. This high anabolic activity was also observed in vivo when the lipidated PB1d6A9 (PB1d6A9-Pal) was intravenously administered once weekly to ovariectomized mice, leading to complete rescue of bone loss. The potent osteogenic properties of this peptide shows great promise as an addition to the current anabolic treatment options for bone diseases such as osteoporosis.

Spatially-resolved correlative microscopy and microbial identification reveals dynamic depth- and mineral-dependent anabolic activity in salt marsh sediment

Coastal salt marshes are key sites of biogeochemical cycling and ideal systems in which to investigate the community structure of complex microbial communities. Here, we clarify structural-functional relationships among microorganisms and their mineralogical environment, revealing previously undescribed metabolic activity patterns and precise spatial arrangements within salt marsh sediment. Following 3.7-day in situ incubations with a non-canonical amino acid that was incorporated into new biomass, samples were embedded and analyzed by correlative fluorescence and electron microscopy to map the microscale arrangements of anabolically active and inactive organisms alongside mineral grains. Parallel sediment samples were examined by fluorescence-activated cell sorting and 16S rRNA gene sequencing to link anabolic activity to taxonomic identity. Both approaches demonstrated a rapid decline in the proportion of anabolically active cells with depth into salt marsh sediment, from ∼60% in the top cm to 10-25% between 2-7 cm. From the top to the bottom, the most prominent active community members shifted from sulfur cycling phototrophic consortia, to sulfate-reducing bacteria likely oxidizing organic compounds, to fermentative lineages. Correlative microscopy revealed more abundant (and more anabolically active) organisms around non-quartz minerals including rutile, orthoclase, and plagioclase. Microbe-mineral relationships appear to be dynamic and context-dependent arbiters of biogeochemical cycling.Statement of SignificanceMicroscale spatial relationships dictate critical aspects of a microbiome’s inner workings and emergent properties, such as evolutionary pathways, niche development, and community structure and function. However, many commonly used methods in microbial ecology neglect this parameter – obscuring important microbe-microbe and microbe-mineral interactions – and instead employ bulk-scale methodologies that are incapable of resolving these intricate relationships.This benchmark study presents a compelling new approach for exploring the anabolic activity of a complex microbial community by mapping the precise spatial configuration of anabolically active organisms within mineralogically heterogeneous sediment through in situ incubation, resin embedding, and correlative fluorescence and electron microscopy. In parallel, active organisms were identified through fluorescence-activated cell sorting and 16S rRNA gene sequencing, enabling a powerful interpretive framework connecting location, identity, activity, and putative biogeochemical roles of microbial community members.We deploy this novel approach in salt marsh sediment, revealing quantitative insights into the fundamental principles that govern the structure and function of sediment-hosted microbial communities. In particular, at different sediment horizons, we observed striking changes in the proportion of anabolically active cells, the identities of the most prominent active community members, and the nature of microbe-mineral affiliations. Improved approaches for understanding microscale ecosystems in a new light, such as those presented here, reveal environmental parameters that promote or constrain metabolic activity and clarify the impact that microbial communities have on our world.