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Proteins perform most cellular functions in macromolecular complexes. The same protein often participates in different complexes to exhibit diverse functionality. Current ensemble approaches of identifying cellular protein interactions cannot reveal physiological permutations of these interactions. Here we describe a single-molecule pull-down (SiMPull) assay that combines the principles of a conventional pull-down assay with single-molecule fluorescence microscopy and enables direct visualization of individual cellular protein complexes. SiMPull can reveal how many proteins and of which kinds are present in the in vivo complex, as we show using protein kinase A. We then demonstrate a wide applicability to various signalling proteins found in the cytosol, membrane and cellular organelles, and to endogenous protein complexes from animal tissue extracts. The pulled-down proteins are functional and are used, without further processing, for single-molecule biochemical studies. SiMPull should provide a rapid, sensitive and robust platform for analysing protein assemblies in biological pathways. Protein complexes at single-molecule resolution Analysis of protein interactions is crucial for understanding cellular function and regulation. Here, Taekjip Ha and colleagues develop a novel method for elucidating the identity and stoichiometry of protein complexes from cells and tissues at single-molecule resolution. The method, called single molecule pull-down or SiMPull, can discriminate between multiple association states of a protein, and simultaneously allows determination of complex stoichiometry through photobleaching step analysis. The potential of the assay is demonstrated in a variety of contexts, including endogenous proteins from tissue extracts, organelles and membrane proteins.

Metabolic profiling, metabolomic and metabonomic studies mainly involve the multicomponent analysis of biological fluids, tissue and cell extracts using NMR spectroscopy and/or mass spectrometry (MS). We summarize the main NMR spectroscopic applications in modern metabolic research, and provide detailed protocols for biofluid (urine, serum/plasma) and tissue sample collection and preparation, including the extraction of polar and lipophilic metabolites from tissues. 1 H NMR spectroscopic techniques such as standard 1D spectroscopy, relaxation-edited, diffusion-edited and 2D J-resolved pulse sequences are widely used at the analysis stage to monitor different groups of metabolites and are described here. They are often followed by more detailed statistical analysis or additional 2D NMR analysis for biomarker discovery. The standard acquisition time per sample is 4–5 min for a simple 1D spectrum, and both preparation and analysis can be automated to allow application to high-throughput screening for clinical diagnostic and toxicological studies, as well as molecular phenotyping and functional genomics.

With the worldwide increase of fisheries, fish wastes have had a similar increase, alternatively they can be seen as a source of novel substances for the improvement of societyâ s wellbeing. Elasmobranchs are a subclass fished in high amounts, with some species being mainly bycatch. They possess an endoskeleton composed mainly by cartilage, from which chondroitin sulfate is currently obtained. Their use as a viable source for extraction of type II collagen has been hypothesized with the envisaging of a biomedical application, namely in biomaterials production. In the present work, raw cartilage from shark (Prionace glauca) and ray (Zeachara chilensis and Bathyraja brachyurops) was obtained from a fish processing company and submitted to acidic and enzymatic extractions, to produce acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC). From all the extractions, P. glauca PSC had the highest yield (3.5%), followed by ray ASC (0.92%), ray PSC (0.50%), and P. glauca ASC (0.15%). All the extracts showed similar properties, with the SDS-PAGE profiles being compatible with the presence of both type I and type II collagens. Moreover, the collagen extracts exhibited the competence to maintain their conformation at human basal temperature, presenting a denaturation temperature higher than 3 C. Hydrogels were produced using P. glauca PSC combined with shark chondroitin sulfate, with the objective of mimicking the human cartilage extracellular matrix. These hydrogels were cohesive and structurally-stable at 37 C, with rheological measurements exhibiting a conformation of an elastic solid when submitted to shear strain with a frequency up to 4 Hz. This work revealed a sustainable strategy for the valorization of fisheriesâ by-products, within the concept of a circular economy, consisting of the use of P. glauca, Z. chilensis, and B. brachyurops cartilage for the extraction of collagen, which would be further employed in the development of hydrogels as a proof of concept of its biotechnological potential, ultimately envisaging its use in marine biomaterials to regenerate damaged cartilaginous tissues.

Ethanol extract (EE) from Periplaneta americana (PA) is the main ingredient of Kangfuxin, which is a popular traditional chinese medicine (TCM) and has long been used for the clinical treatment of burns, wounds and ulcers. We compared the wound-healing activities of three extracts of PA using cutaneous wound-healing in mice as the bioactivity model. These three extracts were EE, total polysaccharide and total protein. We also tracked bioactive fractions in the EE by organic reagent extraction, column chromatography and HPLC. Seven compounds were successfully identified from the water elution fraction of the EE of PA using UPLC-MS. Among these compounds, four compounds (P2, P3, P4, P5(1)) were first reported in PA. Some of these compounds have been previously reported to have various pharmacological activities that could contribute to the high wound-healing activity of PA.

Fish skins constitute an important fraction of the enormous amount of wastes produced by the fish processing industry, part of which may be valorized through the extraction of gelatins. This research exploited the extraction and characterization of gelatins from the skin of three seawater fish species, namely yellowfin tuna (Thunnus albacares), blue shark (Prionace glauca), and greenland halibut (Reinhardtius hippoglossoides). Characterization included chemical composition, rheology, structure, texture, and molecular weight, whereas extraction studies intended to reduce costly steps during extraction process (reagents concentration, water consumption, and time of processing), while maintaining extraction efficiency. Chemical and physical characterization of the obtained gelatins revealed that the species from which the gelatin was extracted, as well as the heat treatment used, were key parameters in order to obtain a final product with specific properties. Therefore, the extraction conditions selected during gelatin production will drive its utilization into markets with well-defined specifications, where the necessity of unique products is being claimed. Such achievements are of utmost importance to the food industry, by paving the way to the introduction in the market of gelatins with distinct rheological and textural properties, which enables them to enlarge their range of applications.

Elevated oxidative stress plays an important role in the pathogenesis of health disorders, like arthritis. Traditionally, Vespa affinis L., a common edible insect among many tribes in North-East India, is believed to have a beneficial role in extenuating health disorders, such as arthritis. The present study investigated the molecular mechanism underlying medicinal benefit of the Aqueous Extract of Vespa affinis L. (AEVA) against oxidative stress pathophysiology. The free radical scavenging activities of AEVA were examined against DPPH, hydroxyl, and superoxide radicals and the effect on the activities of antioxidant enzyme (GST and CAT) was determined using both recombinant proteins and human plasma. The antioxidant potential of AEVA was again investigated using THP-1 monocytes. AEVA possesses a significant free radical scavenging activity as evident from the DPPH, superoxide, and hydroxyl radical scavenging assay. Incubation of AEVA (2.5, 5, 7.5, and 10 μg/μL) with the recombinant antioxidant enzymes, rGST and rCAT significantly increased the enzyme activities compared to those observed in corresponding enzyme alone or AEVA itself. AEVA supplementation (5, 7.5, and 10 μg/μL) also stimulates the activities of GST and CAT when incubated with human plasma. A cell culture study also confirmed the beneficial role of AEVA (0.8 and 1.2 μg/μL) which enhances the activities of GST and CAT, and also reduces the intercellular ROS production in monocytes treated with or without H2O2 and the effects are at par with what is observed in N-acetyl cysteine-treated cells. The antioxidant potential of the aqueous extract of Vespa affinis L. may mediate its therapeutic activities in oxidative stress-associated health disorders.

Marine organisms are a vital source of biologically active compounds. Organic extracts from the muscle of the Pacific white shrimp (L. vannamei) have shown antiproliferative effects on tumor cells, including breast adenocarcinoma. This study aimed to analyze these extracts’ composition and confirm their specificity for breast adenocarcinoma cells without harming normal cells. An organic chloroform extract from L. vannamei muscle was divided using a solvent partition procedure with methanol and hexane. The methanolic partition was fractionated through an open preparative liquid chromatography column to isolate compounds with biological activity, that were later tested on MDA-MB-231 (breast adenocarcinoma), and recently tested on MCF10-A (non-cancerous breast epithelial cells). Cells incubated with these fractions were assessed for viability and morphological changes using fluorescence confocal microscopy. Fractions F#13 and F#14 reduced MDA-MB-231 cancer cell viability at 100 µg/mL without affecting non-cancerous MCF-10A cells, inducing apoptosis-related changes in cancer cells. These fractions contained EPA and DHA free fatty acids, specifically F#13 contained free and esterified astaxanthin as well. The high levels of free linoleic acid 18:2 ω-6, EPA, and DHA (in a 2:1 ratio, EPA:DHA), along with free and esterified astaxanthin in F#13, significantly reduced breast adenocarcinoma cell viability, nearly to that achieved by cisplatin, a chemotherapy drug.

Phenotypic heterogeneity is commonly observed in diseased tissue, specifically in tumors. Multimodal imaging technologies can reveal tissue heterogeneity noninvasively in vivo, enabling imaging-based profiling of receptors, metabolism, morphology, or function on a macroscopic scale. In contrast, in vitro multiomics, immunohistochemistry, or histology techniques accurately characterize these heterogeneities in the cellular and subcellular scales in a more comprehensive but ex vivo manner. The complementary in vivo and ex vivo information would provide an enormous potential to better characterize a disease. However, this requires spatially accurate coregistration of these data by image-driven sampling as well as fast sample-preparation methods. Here, a unique image-guided milling machine and workflow for precise extraction of tissue samples from small laboratory animals or excised organs has been developed and evaluated. The samples can be delineated on tomographic images as volumes of interest and can be extracted with a spatial accuracy better than 0.25 mm. The samples remain cooled throughout the procedure to ensure metabolic stability, a precondition for accurate in vitro analysis.

Sea cucumbers are bottom dwelling invertebrates, which are mostly found on subtropical and tropical sea grass beds, sandy reef flats, or reef slopes. Although constantly exposed to fouling communities in these habitats, many species are surprisingly free of invertebrate epibionts and microfouling algae such as diatoms. In our study, we investigated the anti-fouling (AF) activities of different crude extracts of tropical Indo-Pacific sea cucumber species against the fouling diatom Cylindrotheca closterium. Nine sea cucumber species from three genera (i.e., Holothuria, Bohadschia, Actinopyga) were selected and extracted to assess their AF activities. To verify whether the sea cucumber characteristic triterpene glycosides were responsible for the observed potent AF activities, we tested purified fractions enriched in saponins isolated from Bohadschia argus, representing one of the most active anti-fouling extracts. Saponins were quantified by vanillin-sulfuric acid colorimetric assays and identified by LC-MS and LC-MS/MS analyses. We were able to demonstrate that AF activities in sea cucumber extracts were species-specific, and growth inhibition as well as attachment of the diatom to surfaces is dependent on the saponin concentration (i.e., Actinopyga contained the highest quantities), as well as on the molecular composition and structure of the present saponins (i.e., Bivittoside D derivative was the most bioactive compound). In conclusion, the here performed AF assay represents a promising and fast method for selecting the most promising bioactive organism as well as for identifying novel compounds with potent AF activities for the discovery of potentially novel pharmacologically active natural products.

Recent animal studies found the potential of a collagen peptide derived from skate skin to have anti-obesity effects through the suppression of fat accumulation and regulation of lipid metabolism. However, no studies have yet been performed in humans. Here, this very first human randomized, placebo-controlled, and double-blinded study was designed to investigate the efficacy and tolerability of skate skin collagen peptides (SCP) for the reduction of body fat in overweight adults. Ninety healthy volunteers (17 men) aged 41.2 ± 10.4 years with a mean body mass index of 25.6 ± 1.9 kg/m2 were assigned to the intervention group (IG), which received 2000 mg of SCP per day or to the control group (CG) given the placebo for 12 weeks and 81 (90%) participants completed the study. Changes in body fat were evaluated using dual energy X-ray absorptiometry as a primary efficacy endpoint. After 12 weeks of the trial, the percentage of body fat and body fat mass (kg) in IG were found to be significantly better than those of subjects in CG (−1.2% vs. 2.7%, p = 0.024 and −1.2 kg vs. 0.3 kg, p = 0.025). Application of SCP was well tolerated and no notable adverse effect was reported from both groups. These results suggest the beneficial potential of SCP in the reduction of body fat in overweight adults.