An absolute method for protein determination based on difference in absorbance at 235 and 280 nm

Antimicrobial Cyclic Dipeptides from Japanese Quail (Coturnix japonica) Eggs Supplemented with Probiotic Lactobacillus plantarum

Fifteen cyclic dipeptides (CDPs) containing proline, one cyclo(Phe-Ala) without proline, and a non-peptidyl DL-3-phenyllactic acid were previously identified in the culture filtrates of Lactobacillus plantarum LBP-K10, an isolate from kimchi. In this study, we used Japanese quail (Coturnix japonica) eggs to examine the effects of probiotic supplementation on the antimicrobial CDPs extracted from quail eggs (QE). Eggshell-free QE were obtained from two distinct groups of quails. The first group (K10N) comprised eggs from unsupplemented quails. The second group (K10S) comprised eggs from quails supplemented with Lb. plantarum LBP-K10. The QE samples were extracted using methylene chloride through a liquid-liquid extraction process. The resulting extract was fractionated into 16 parts using semi-preparative high-performance liquid chromatography. Two fractions, Q6 and Q9, were isolated from K10S and identified as cis-cyclo(L-Ser-L-Pro) and cis-cyclo(L-Leu-L-Pro). The Q9 fraction, containing cis-cyclo(L-Leu-L-Pro), has shown significant inhibitory properties against the proliferation of highly pathogenic multidrug-resistant bacteria, as well as human-specific and phytopathogenic fungi. Some of the ten combinations between the remaining fourteen unidentified fractions and two fractions, Q6 and Q9, containing cis-cyclo(L-Ser-L-Pro) and cis-cyclo(L-Leu-L-Pro) respectively, demonstrated a significant increase in activity against multidrug-resistant bacteria only when combined with Q9. The activity was 7.17 times higher compared to a single cis-cyclo(L-Leu-L-Pro). This study presents new findings on the efficacy of proline-containing CDPs in avian eggs. These CDPs provide antimicrobial properties when specific probiotics are supplemented.

Microplastics elicit an immune-agitative state in coral

Microplastic pollution in the ocean is a major problem, as its pervasiveness elicits concerns the health impacts microplastics may have on marine life (such as reef-building corals). As a primary endpoint, the organismal lipidome can define the weakening of fitness and reveal the physiological context of adverse health effects in organisms. To gain insight into the effects of microplastics on coral health, lipid profiling was performed via an untargeted lipidomic approach on the coral Turbinaria mesenterina exposed to ~10 μm polystyrene microparticles for 10 days. Considerable microplastic accumulation and obvious effects relating with immune activation were observed in the coral treated with a near environmentally relevant concentration of microplastics (10 μg/L); however, these effects were not evident in the high level (100 μg/L) treatment group. In particular, increased levels of membrane lipids with 20:4 and 22:6 fatty acid chains reallocated from the triacylglycerol pool were observed in coral host cells and symbiotic algae, respectively, which could upregulate immune activity and realign symbiotic communication in coral. High levels of polyunsaturation can sensitize the coral cell membrane to lipid peroxidation and increase cell death, which is of greater concern; additionally, the photoprotective capacity of symbiotic algae was compromised. As a result, coral physiological functions were altered. These results show that, realistic levels of microplastic pollution can affect coral health and should be a concern.

Marine heatwaves modulate the genotypic and physiological responses of reef-building corals to subsequent heat stress

Back-to-back marine heatwaves in 2016 and 2017 resulted in severe coral bleaching and mortality across the Great Barrier Reef (GBR). Encouragingly, some corals that survived these events exhibit increased bleaching resistance and may represent thermally tolerant populations that can better cope with ocean warming. Using the GBR as a natural laboratory, we investigated whether a history of minimal (Heron Island) or severe (Lizard Island) coral bleaching in 2016 and 2017 equates to stress tolerance in a successive heatwave (2020). We examined the genetic diversity, physiological performance, and trophic plasticity of juvenile (<10 cm) and adult (>25 cm) corals of two common genera (Pocillopora and Stylophora). Despite enduring greater cumulative heat stress (6.3°C week-1 vs. 5.6°C week-1), corals that experienced the third marine heatwave in 5 years (Lizard) exhibited twice as high survival and visual bleaching thresholds compared to corals that had not experienced significant bleaching in >10 years (Heron). Surprisingly, only one shared host-Symbiodiniaceae association was uncovered between locations (Stylophora pistillata-Cladocopium "C8 group") and there was no genetic overlap in Pocillopora-Cladocopium partnerships, suggesting turnover in species composition from recent marine heatwaves. Corals within the species complex Pocillopora that survived the 2016 and 2017 marine heatwaves at Lizard Island were the most resilient, exhibiting three times greater calcification rates than conspecifics at Heron Island. Further, surviving corals (Lizard) had distinct isotopic niches, lower host carbon, and greater host protein, while conspecifics that had not experienced recent bleaching (Heron) had two times greater symbiont carbon content, suggesting divergent trophic strategies that influenced survival (i.e., greater reliance on heterotrophy vs. symbiont autotrophy, respectively). Ultimately, while corals may experience less bleaching and survive repeated thermal stress events, species-specific trade-offs do occur, leaving open many questions related to the long-term health and recovery of coral reef ecosystems in the face of intensifying marine heatwaves.

Evaluation of the current understanding of the impact of climate change on coral physiology after three decades of experimental research

After three decades of coral research on the impacts of climate change, there is a wide consensus on the adverse effects of heat-stress, but the impacts of ocean acidification (OA) are not well established. Using a review of published studies and an experimental analysis, we confirm the large species-specific component of the OA response, which predicts moderate impacts on coral physiology and pigmentation by 2100 (scenario-B1 or SSP2-4.5), in contrast with the severe disturbances induced by only +2 °C of thermal anomaly. Accordingly, global warming represents a greater threat for coral calcification than OA. The incomplete understanding of the moderate OA response relies on insufficient attention to key regulatory processes of these symbioses, particularly the metabolic dependence of coral calcification on algal photosynthesis and host respiration. Our capacity to predict the future of coral reefs depends on a correct identification of the main targets and/or processes impacted by climate change stressors.

Environmental memory gained from exposure to extreme pCO2 variability promotes coral cellular acid-base homeostasis

Ocean acidification is a growing threat to coral growth and the accretion of coral reef ecosystems. Corals inhabiting environments that already endure extreme diel pCO₂ fluctuations, however, may represent acidification-resilient populations capable of persisting on future reefs. Here, we examined the impact of pCO₂ variability on the reef-building coral Pocillopora damicornis originating from reefs with contrasting environmental histories (variable reef flat versus stable reef slope) following reciprocal exposure to stable (218 ± 9) or variable (911 ± 31) diel pCO₂ amplitude (μtam) in aquaria over eight weeks. Endosymbiont density, photosynthesis and net calcification rates differed between origins but not treatment, whereas primary calcification (extension) was affected by both origin and acclimatization to novel pCO₂ conditions. At the cellular level, corals from the variable reef flat exhibited less intracellular pH (pHi) acidosis and faster pHi recovery rates in response to experimental acidification stress (pH 7.40) than corals originating from the stable reef slope, suggesting environmental memory gained from lifelong exposure to pCO₂ variability led to an improved ability to regulate acid–base homeostasis. These results highlight the role of cellular processes in maintaining acidification resilience and suggest that prior exposure to pCO₂ variability may promote more acidification-resilient coral populations in a changing climate.

Mode of action of nanochitin whisker against Fusarium pseudograminearum

Nanochitin whisker (NC) is an advanced nanobiomaterial with novel physicochemical and biological properties. Fusarium pseudograminearum (Fpg) is an important pathogenic fungus causing wheat crown rot disease. This study explored the mode of action of NC against Fpg as a target microorganism. The effects of different treatments and concentrations of NC on the fungal growth and conidial germination were investigated by in vitro bioassay. The impacts of NC on cell structure integrity, membrane permeability, pathogenesis related key enzymes activity, and the mycotoxin production were examined by electron microscopy, fluorescence spectroscopy, IR spectroscopy, conductometry, and spectrophotometry, respectively. The results showed that NC significantly reduced hyphal growth, and the spore germination rate of Fpg declined by 33.0 % and 23.2 % when Fpg was treated with 30 and 300 μg/mL of NC, respectively. NC vigorously influenced structural stability of cell wall by destroying dextran structure, and strongly stimulated ergosterol production altering membrane integrity of the fungus. It reduced the activities of enzymes related to energy-supply like nicotinamide adenine dinucleotide oxidase and succinate dehydrogenase remarkably. The production of fungal mycotoxin deoxynivalenol was also decreased by NC. These findings provide an important basis for fully understanding the mechanism of nanobiomaterial in plant fungal disease control.

Investigation of Protein Corona Formed around Biologically Produced Gold Nanoparticles

Although there are several research articles on the detection and characterization of protein corona on the surface of various nanoparticles, there are no detailed studies on the formation, detection, and characterization of protein corona on the surface of biologically produced gold nanoparticles (AuNPs). AuNPs were prepared from Fusarium oxysporum at two different temperatures and characterized by spectrophotometry, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). The zeta potential of AuNPs was determined using a Zetasizer. AuNPs were incubated with 3 different concentrations of mouse plasma, and the hard protein corona was detected first by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and then by electrospray liquid chromatography–mass spectrometry (LC-MS). The profiles were compared to AuNPs alone that served as control. The results showed that round and oval AuNPs with sizes below 50 nm were produced at both temperatures. The AuNPs were stable after the formation of the protein corona and had sizes larger than 86 nm, and their zeta potential remained negative. We found that capping agents in the control samples contained small peptides/amino acids but almost no protein(s). After hard protein corona formation, we identified plasma proteins present on the surface of AuNPs. The identified plasma proteins may contribute to the AuNPs being shielded from phagocytizing immune cells, which makes the AuNPs a promising candidate for in vivo drug delivery. The protein corona on the surface of biologically produced AuNPs differed depending on the capping agents of the individual AuNP samples and the plasma concentration.

Colonies of Acropora formosa with greater survival potential have reduced calcification rates

Coral reefs are facing increasingly devasting impacts from ocean warming and acidification due to anthropogenic climate change. In addition to reducing greenhouse gas emissions, potential solutions have focused either on reducing light stress during heating, or on the potential for identifying or engineering “super corals”. A large subset of these studies, however, have tended to focus primarily on the bleaching response of corals, and assume erroneously that corals that bleach earlier in a thermal event die first. Here, we explore how survival, observable bleaching, coral skeletal growth (as branch extension and densification), and coral tissue growth (protein and lipid concentrations) varies for conspecifics collected from distinctive reef zones at Heron Island on the Southern Great Barrier Reef. A reciprocal transplantation experiment was undertaken using the dominant reef building coral (Acropora formosa) between the highly variable reef flat and the less variable reef slope environments. Coral colonies originating from the reef flat had higher rates of survival and amassed greater protein densities but calcified at reduced rates compared to conspecifics originating from the reef slope. The energetics of both populations however potentially benefited from greater light intensity present in the shallows. Reef flat origin corals moved to the lower light intensity of the reef slope reduced protein density and calcification rates. For A. formosa, genetic differences, or long-term entrainment to a highly variable environment, appeared to promote coral survival at the expense of calcification. The response decouples coral survival from carbonate coral reef resilience, a response that was further exacerbated by reductions in irradiance. As we begin to discuss interventions necessitated by the CO₂ that has already been released into the atmosphere, we need to prioritise our focus on the properties that maintain valuable carbonate ecosystems. Rapid and dense calcification by corals such as branching Acropora is essential to the ability of carbonate coral reefs to rebound following disturbance events and maintain 3D structure but may be the first property that is sacrificed to enable coral genet survival under stress.

Lipid profiling of coral symbiosomes in response to copper-induced carbon limitation: A metabolic effect of algal symbionts on the host immune status

Copper micropollutants are known to constrain coral's assimilation of carbonate, affecting the carbon available to algal symbionts and thus inducing a light stress. However, little is known regarding the physiological relevance of lipid metabolism in coral symbiotic algae in a carbon-limited state. Membrane lipids exhibit multiple physicochemical properties that are collectively responsible for the dynamic structure of cells depending on the physiological demands of the circumstances. To gain insight into lipid metabolism's importance in this regard, glycerophosphocholine (GPC) profiling of symbiosomes in coral (Seriatopora caliendrum) exposed to environmentally relevant copper levels (2.2-7.5 μg/L) for 4 days was performed in this study. Notably, reducing the number of 22:6-processing GPCs and increasing that of lyso-GPCs likely addressed the demands of metabolizing excess light energy, such as affecting the membrane dynamics to promote mitochondrial uncoupling. The decrease in 22:6-processing GPCs additionally protected cellular membranes from elevated oxidative stress, reducing their susceptibility to peroxidation and offsetting oxidized lipid-induced effects on membrane dynamics. The change in plasmanylcholines specifically localized within the symbiosome membrane also met the membrane requirements for responding to oxidative stress conditions. Moreover, increasing the 20:4-possessing plasmanylcholines and lysoplasmanylcholines and reducing the 22:6-possessing plasmanylcholines likely resulted in an imbalance of the immune reaction, influencing the coral-algae symbiosis given the role of such plasmanylcholines in cell signaling. In summary, carbon limitations induced by copper enrichment lead to a shift in the membrane lipid profile of coral symbiosomes, accommodating themselves to light stress conditions while compromising the symbiosis's stability.

Macro- and micro-scale adaptations allow distinct Stylophora pistillata-symbiodiniaceae holobionts to optimize performance across a broad light habitat

In sessile organisms, phenotypic plasticity represents an important strategy for dealing with environmental variability. Here we test if phenotypic plasticity enables the common coral Stylophora pistillata to occupy a broad niche. We find clear differences in the photo-physiology of four putative species of photosynthetic dinoflagellate symbionts associated with the coral S. pistillata, namely, Cladocopium 'C35a', 'C79', 'C78a' and 'C8a'. Coral phenotypic responses were also tightly linked to symbiont identity. Corals with Cladocopium 'C8a' have more "open" macro-morphology compared to colonies associating with depth-restricted Cladocopium 'C35a' or 'C78a' in the same shallow water habitat. Corals with Cladocopium 'C8a' had 40 to 60% lower symbiont cell densities compared to other holobionts but were more efficient at acclimating over a range of light levels, with clear mechanisms to dissipate excess light energy. This holobiont contains host-based green fluorescent pigments, increased concentrations of symbiont-based mycosporine amino acids, and xanthophyll cycling in high light habitats. Photosynthetic efficiency was also adjusted over the light habitat. In contrast, limited micro-scale responses were observed between three depth-restricted symbionts: Cladocopium 'C79', 'C35a', and 'C78a'. To optimize light levels reaching the photosynthetic unit, these colonies rely on a more closed macro-morphology under high light levels, which reduces incident light levels by up to 43%, and higher symbiont densities . Our results show that distinct macro- and micro-scale adaptations lead to functional differences between four distinct S. pistillata holobionts, allowing them to co-exist by filling specific niches on a small, but environmentally diverse, spatial scale. Key index words: Light, Symbiodiniaceae, coral, pigments, Stylophora pistillata, ITS2, phenotypic plasticity, niche diversification.

Hippophae rhamnoides L. leaf and twig extracts as rich sources of nutrients and bioactive compounds with antioxidant activity

Plants have served for centuries as sources of compounds useful for human health such as antioxidant, anti-diabetic and antitumor agents. They are also rich in nutrients that improve the human diet. Growing demands for these compounds make it important to seek new sources for them. Hippophae rhamnoides L. is known as a plant with health-promoting properties. In this study we investigated the chemical composition and biological properties of bioactive components of ethanol extracts from leaves and twigs of H. rhamnoides L. Chemical components such as the total content of phenolic compounds, vitamins and amino acids and the antioxidant activities of these compounds in cellular and cell-free systems were assessed. The results suggest that the studied extracts are rich in bioactive compounds with potent antioxidant properties. Cytotoxicity and hemotoxicity assays showed that the extracts had low toxicity on human cells over the range of concentrations tested. Interaction with human serum albumin was investigated and conformational changes were observed. Our results indicate that leaf and twig extracts of H. rhamnoides L. should be considered as a non-toxic source of bioactive compounds which may be of interest to the food, pharmaceutical and cosmetic industries.

Label-Free Physical Techniques and Methodologies for Proteins Detection in Microfluidic Biosensor Structures

Proteins in biological fluids (blood, urine, cerebrospinal fluid) are important biomarkers of various pathological conditions. Protein biomarkers detection and quantification have been proven to be an indispensable diagnostic tool in clinical practice. There is a growing tendency towards using portable diagnostic biosensor devices for point-of-care (POC) analysis based on microfluidic technology as an alternative to conventional laboratory protein assays. In contrast to universally accepted analytical methods involving protein labeling, label-free approaches often allow the development of biosensors with minimal requirements for sample preparation by omitting expensive labelling reagents. The aim of the present work is to review the variety of physical label-free techniques of protein detection and characterization which are suitable for application in micro-fluidic structures and analyze the technological and material aspects of label-free biosensors that implement these methods. The most widely used optical and impedance spectroscopy techniques: absorption, fluorescence, surface plasmon resonance, Raman scattering, and interferometry, as well as new trends in photonics are reviewed. The challenges of materials selection, surfaces tailoring in microfluidic structures, and enhancement of the sensitivity and miniaturization of biosensor systems are discussed. The review provides an overview for current advances and future trends in microfluidics integrated technologies for label-free protein biomarkers detection and discusses existing challenges and a way towards novel solutions.

The specific inhibition of glycerol synthesis and the phosphorylation of a putative MAPK give insight into the mechanism of osmotic sensing in a dinoflagellate symbiont

Signaling pathways are fundamental for the establishment and maintenance of diverse symbioses. The symbiosis of cnidarians and dinoflagellate algae is the foundation for the ecological success of coral reefs, involving the transfer of photosynthetic products from symbiont to host. However, signal transduction pathways for this symbiosis remain uncharacterized. Cultured and natural cnidarian symbionts can produce glycerol, one of the main translocated photosynthates. Here, we investigate whether a signal transduction pathway may be involved in inducing glycerol synthesis in cultured symbionts under an osmotic stress model. We evaluated the effect of specific inhibitors of the main transduction pathways, p38, JNK, and ERK 1/2 in Brevolium minutum, the symbiont of the Aiptasia model system. We found that glycerol production and the specific activity of the enzyme Gpdh were selectively inhibited by a p38 MAPK inhibitor. Additionally, the phosphorylation of a putative p38-like protein was rapidly detected. Finally, we studied the presence of each of the components of the p38 MAPK pathway in silico, in genomes and transcriptomes reported up to date for different symbiont types. We propose a model for the arrangement of this pathway in the family of dinoflagellate symbionts known as Symbiodiniaceae.

Changes of structures and biosynthesis/hydrolysis-associated genes expression of glucans at different Volvariella volvacea maturity stages

In the present study, effects of maturity stage on structural characteristics and biosynthesis/hydrolysis-associated genes expression of glucans from Volvariella volvacea fruit body were well investigated. Elongation and pileus expansion stages decreased total soluble carbohydrate and protein contents to 17.09 mg/g and 8.33 mg/g, and significantly accumulated the total amino acids contents to 32.37 mg/g. Yields of crude polysaccharides significantly increased to 8.12% at egg stage and decreased to 3.72% at pileus expansion stage. Purified VVP I-a and VVP I-b were proved to be α-glucans. The maturity process affected the monosaccharide compositions, decreased the molecular weights of VVP I-a and VVP I-b with decreased transcription levels of glucan biosynthesis-associated enzyme genes vvugp and vvgls and increased glucan hydrolysis-associated glucanase gene vvexg2 expression with no significant effects on backbone structures including glycosidic linkages and configurations. The findings would benefit for understanding change patterns of V. volvacea glucan structures and their biosynthesis/hydrolysis-associated genes expression at maturity stages.

Antioxidant and hemostatic properties of preparations from Asteraceae family and their chemical composition - Comparative studies

Asteraceae, known as sunflower family, is one of the largest flowering plants family around the world. Sunflower family contains numerous phytochemical compounds. The aim of this study was to describe phytochemical characteristics and investigate the effect of four sunflower vegetable preparations (extracts): chicory leaves (Cichorium intybus), green lettuce leaves (Lactuca sativa), red lettuce leaves (Lactuca sativa var. crispa) and sunchoke roots (Helianthus tuberosus) on different biomarkers of oxidative stress in human plasma in in vitro model. The antioxidant potential was also tested using the DPPH method. The phytochemical composition of the tested preparations was determined by UPLC-ESI-QTOF-MS. All the tested extracts demonstrated antioxidant activity in human plasma. We have observed chicory's and sunchoke's extracts had strongest antioxidant properties in the used models with human plasma. None of the tested vegetables changed ORAC and TAC in vitro. The obtained results suggest that sunflower vegetables might help to prevent oxidative stress related with cardiovascular diseases.

Asymmetric physiological response of a reef-building coral to pulsed versus continuous addition of inorganic nutrients

Coral reefs, especially those located near-shore, are increasingly exposed to anthropogenic, eutrophic conditions that are often chronic. Yet, corals under unperturbed conditions may frequently receive natural and usually temporary nutrient supplementation through biological sources such as fishes. We compared physiological parameters indicative of long- and short-term coral health (day and night calcification, fragment surface area, productivity, energy reserves, and tissue stoichiometry) under continuous and temporary nutrient enrichment. The symbiotic coral Acropora intermedia was grown for 7 weeks under continuously elevated (press) levels of ammonium (14 µmol L^-1) and phosphate (10 µmol L^-1) as separate and combined treatments, to discern the individual and interactive nutrient effects. Another treatment exposed A. intermedia twice-daily to an ammonium and phosphate pulse of the same concentrations as the press treatments to simulate natural biotic supplementation. Press exposure to elevated ammonium or phosphate produced mixed effects on physiological responses, with little interaction between the nutrients in the combined treatment. Overall, corals under press exposure transitioned resources away from calcification. However, exposure to nutrient pulses often enhanced physiological responses. Our findings indicate that while continuous nutrient enrichment may pose a threat to coral health, episodic nutrient pulses that resemble natural nutrient supplementation may significantly benefit coral health and physiology.

Multifunctional compounds in the extract from mature seeds of Vicia faba var. minor: Phytochemical profiling, antioxidant activity and cellular safety in human selected blood cells in in vitro trials

BACKGROUND

The field bean (Vicia faba) is a valuable fodder plant of the Fabaceae family, grown as a main crop for its seed yield. Its phytochemical profile is characterized by the presence of a range of compounds with various biological activities.

PURPOSE

The present study investigates the phytochemical profile of the extract from mature seeds of Vicia faba var. minor and examines its impact on preventing oxidative damage to various lipids, protein and DNA molecules in vitro.

METHODS

Human plasma was treated with H₂O₂/Fe (an OH^. donor) to induce oxidative damage to lipids and proteins, and the plant extract was then added. As oxidative stress may influence the biological activity of plasma, e.g. coagulation, and influence cardiovascular disease, the study also examined the effect of the plant extract on coagulation and monoamine oxidase activity (MAO, EC 1.4.3.4).

RESULTS

The tested extract exerted a protective effect on plasma lipids and proteins treated with H₂O₂/Fe. However, while it appears to effectively protect the DNA in peripheral blood mononuclear cells from oxidative damage, it did not induce changes in the coagulation process, and significantly reduced MAO activity when applied at 1, 5, and 10 µg/mL. It is possible that the observed antioxidant potential may be due to the complex chemical composition of the extract: the phytochemical profile demonstrated a range of phenolic compounds, including catechins.

CONCLUSION

Our findings indicate that extract from mature seeds of V. faba var. minor may be a promising source of antioxidants in multiple applications, including diseases associated with oxidative stress; however, more studies based on in vitro and in vivo models are needed to determine its biological properties.

Evaluation of Antimicrobial, Antioxidant, and Cytotoxic Activity of Phenolic Preparations of Diverse Composition, Obtained from Elaeagnus rhamnoides (L.) A. Nelson Leaf and Twig Extracts

Although the major components of various organs of sea buckthorn have been identified (particularly phenolic compounds), biological properties of many of these phytochemicals still remain poorly characterized. In this study, we focused on the chemical composition and biological activity of preparations that were obtained from sea buckthorn twigs and leaves. The objective was to investigate cytotoxicity of these preparations against human fibroblast line HFF-1, using MTT reduction assay, their anti- or pro-oxidant activities against the effects of a biological oxidant -H₂O₂/Fe-on human plasma lipids and proteins in vitro (using TBARS and carbonyl groups as the markers of oxidative stress). Antimicrobial activity of the tested preparations against Gram-positive (Staphylococcus aureus, S. epidermidis, Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), as well as against fungi (Candida albicans, C. glabrata) by the EUCAST-approved broth microdilution method, followed by growth on solid media, were also assessed. Our analysis showed significant differences in chemical composition and biological properties of the tested preparations (A-F). All tested preparations from sea buckthorn twigs (D-F) and one preparation from sea buckthorn leaves (preparation C) may be a new source of phenolic antioxidants for pharmacological and cosmetic applications.

Antioxidant and anticoagulant effects of phenylpropanoid glycosides isolated from broomrapes (Orobanche caryophyllacea, Phelipanche arenaria, and P. ramosa)

Holoparasitic plants of the Orobanchaceae, including Cistanche, Orobanche, and Phelipanche spp, are known for their richness of phenylpropanoid glycosides (PPGs). Many PPG compounds have been found to possess a wide spectrum of activities, such as antimicrobial, anti-inflammatory, antioxidant, and memory-enhancing. To better explore the bioactivity potential of European broomrapes (O. caryophyllacea - OC, P. arenaria - PA, P. ramosa - PR) and ten single isolated phenylpropanoid constituents, we investigated their antiradical action, protective effect against oxidation in plasma in vitro system, and influence on coagulation parameters. The tested extracts showed a scavenging activity of 50-70% of Trolox's power. The OC extract, rich in acteoside, had over 20% better antiradical potential than PR extract which was the only one containing PPGs lacking a B-ring catechol moiety in the acyl unit. Moreover, it was found that only eight tested PPGs demonstrated antioxidant potential in human plasma treated with H₂O₂/Fe; however, the three tested PPGs possessed anticoagulant potential in addition to antioxidant properties. It appears that the structure of PPGs, especially the presence of acyl and catechol moieties, is mainly related to their antioxidant properties. The anticoagulant potential of these compounds is also related to their chemical structure. Selected PPGs exhibit the potential for treating cardiovascular diseases associated with oxidative stress.

Morphological stasis masks ecologically divergent coral species on tropical reefs

Coral reefs are the epitome of species diversity, yet the number of described scleractinian coral species, the framework-builders of coral reefs, remains moderate by comparison. DNA sequencing studies are rapidly challenging this notion by exposing a wealth of undescribed diversity, but the evolutionary and ecological significance of this diversity remains largely unclear. Here, we present an annotated genome for one of the most ubiquitous corals in the Indo-Pacific (Pachyseris speciosa) and uncover, through a comprehensive genomic and phenotypic assessment, that it comprises morphologically indistinguishable but ecologically divergent lineages. Demographic modeling based on whole-genome resequencing indicated that morphological crypsis (across micro- and macromorphological traits) was due to ancient morphological stasis rather than recent divergence. Although the lineages occur sympatrically across shallow and mesophotic habitats, extensive genotyping using a rapid molecular assay revealed differentiation of their ecological distributions. Leveraging "common garden" conditions facilitated by the overlapping distributions, we assessed physiological and quantitative skeletal traits and demonstrated concurrent phenotypic differentiation. Lastly, spawning observations of genotyped colonies highlighted the potential role of temporal reproductive isolation in the limited admixture, with consistent genomic signatures in genes related to morphogenesis and reproduction. Overall, our findings demonstrate the presence of ecologically and phenotypically divergent coral species without substantial morphological differentiation and provide new leads into the potential mechanisms facilitating such divergence. More broadly, they indicate that our current taxonomic framework for reef-building corals may be scratching the surface of the ecologically relevant diversity on coral reefs, consequently limiting our ability to protect or restore this diversity effectively.

Modulation of Oxidative Stress and Hemostasis by Flavonoids from Lentil Aerial Parts

While specific metabolites of lentil (Lens culinaris L.) seeds and their biological activity have been well described, other organs of this plant have attracted little scientific attention. In recent years, green parts of lentils have been shown to contain diverse acylated flavonoids. This work presents the results of the research on the effect of the crude extract, the phenolic fraction, and seven flavonoids obtained from aerial parts of lentils on oxidative damage induced by H₂O₂/Fe to lipid and protein constituents of human plasma. Another goal was to determine their effect on hemostasis parameters of human plasma in vitro. Most of the purified lentil flavonoids had antioxidant and anticoagulant properties. The crude extract and the phenolic fraction of lentil aerial parts showed antioxidant activity, only at the highest tested concentration (50 μg/mL). Our results indicate that aerial parts of lentils may be recommended as a source of bioactive substances.

Structural and functional characterization of the glutathione peroxidase-like thioredoxin peroxidase from the fungus Trichoderma reesei

Glutathione peroxidases (GPx) are a family of enzymes with the ability to reduce organic and inorganic hydroperoxides to the corresponding alcohols using glutathione or thioredoxin as an electron donor. Here, we report the functional and structural characterization of a GPx identified in Trichoderma reesei (TrGPx). TrGPx was recombinantly expressed in a bacterial host and purified using affinity. Using a thioredoxin coupled assay, TrGPx exhibited activity of 28 U and 12.5 U in the presence of the substrates H₂O₂ and t-BOOH, respectively, and no activity was observed when glutathione was used. These results indicated that TrGPx is a thioredoxin peroxidase and hydrolyses H₂O₂ better than t-BOOH. TrGPx kinetic parameters using a pyrogallol assay resulted at K_mapp = 11.7 mM_, V_maxapp = 10.9 IU/μg TrGPx, k_cat = 19 s^-1 and a catalytic efficiency of 1.6 mM^-1 s^-1 to H₂O₂ as substrate. Besides that, TrGPx demonstrated an optimum pH ranging from 9.0-12.0 and a half-life of 36 min at 80 °C. TrGPx 3D-structure was obtained in a reduced state and non-catalytic conformation. The overall fold is similar to the other phospholipid-hydroperoxide glutathione peroxidases. These data contribute to understand the antioxidant mechanism in fungi and provide information for using antioxidant enzymes in biotechnological applications.

Flavonoid Preparations from Taraxacum officinale L. Fruits-A Phytochemical, Antioxidant and Hemostasis Studies

Dandelion (Taraxacum officinale L.) roots, leaves, and flowers have a long history of use in traditional medicine. Compared to the above organs, dandelion fruits are the least known and used. Hence, the present paper was aimed at the phytochemical analysis of T. officinale fruit extract and estimating its antiradical, antiplatelet, and antioxidant properties related to hemostasis. Methanolic extract of fruits (E1), enriched with polyphenols (188 mg gallic acid equivalents (GAE)/g), was successfully separated into cinnamic acids (E2; 448 mg GAE/g) and flavonoids (E3; 377 mg GAE/g) extracts. Flavonoid extract was further divided into four fractions characterized by individual content: A (luteolin fraction; 880 mg GAE/g), B (philonotisflavone fraction; 516 mg GAE/g), C (flavonolignans fraction; 384 mg GAE/g), and D (flavone aglycones fraction; 632 mg GAE/g). High DPPH radical scavenging activity was evaluated for fractions A and B (A > B > Trolox), medium for extracts (Trolox > E3 > E2 > E1), and low for fractions C and D. No simple correlation between polyphenol content and antiradical activity was observed, indicating a significant influence of qualitative factor, including higher anti-oxidative effect of flavonoids with B-ring catechol system compared to hydroxycinnamic acids. No cytotoxic effect on platelets was observed for any dandelion preparation tested. In experiments on plasma and platelets, using several different parameters (lipid peroxidation, protein carbonylation, oxidation of thiols, and platelet adhesion), the highest antioxidant and antiplatelet potential was demonstrated by three fruit preparations–hydroxycinnamic acids extract (E2), flavonoid extract (E3), and luteolin fraction (A). The results of this paper provide new information on dandelion metabolites, as well as their biological potential and possible use concerning cardiovascular diseases.

Comparative Phytochemical, Antioxidant, and Hemostatic Studies of Extract and Four Fractions from Paulownia Clone in Vitro 112 Leaves in Human Plasma

Background: The Paulownia Clone in Vitro 112, known as oxytree or oxygen tree, is a hybrid clone of the species Paulownia elongata and Paulownia fortunei (Paulowniaceae). The oxytree is a fast-growing hybrid cultivar that can adapt to wide variations in edaphic and climate conditions. In this work, Paulownia Clone in Vitro 112 leaves were separated into an extract and four fractions (A–D) differing in chemical content in order to investigate their chemical content using LC-MS analysis. The extract and fractions were also evaluated for their anticoagulant and antioxidant properties in a human plasma in vitro. Results: The Paulownia leaf extract contained mainly phenolic compounds (e.g., verbascoside), small amounts of iridoids (e.g., aucubin or 7-hydroxytometoside) and triterpenoids (e.g., maslinic acid) were also detected. Our results indicate that the extract and fractions have different effects on oxidative stress in human plasma treated with H₂O₂/Fe in vitro, which could be attributed to differences in their chemical content. For example, the extract and all the fractions, at the two highest concentrations of 10 and 50 µg/mL, significantly inhibited the plasma lipid peroxidation induced by H₂O₂/Fe. Fractions C and D, at all tested concentrations (1–50 µg/mL) were also found to protect plasma proteins against H₂O₂/Fe-induced carbonylation. The positive effects of fraction C and D were dependent on the dose. Conclusions: The extract and all four fractions, but particularly fractions C and D, which are rich in phenolic compounds, are novel sources of antioxidants, with an inhibitory effect on oxidative stress in human plasma in vitro. Additionally, the antioxidant potential of fraction D may be associated with triterpenoids.

Comparative Phytochemical, Antioxidant and Haemostatic Studies of Preparations from Selected Vegetables from Cucurbitaceae Family

The aim of this study was to provide detailed insight into the chemical composition and activity of five cucurbit vegetable preparations (pumpkin, zucchini, cucumber, white and yellow pattypan squash), each containing various phytochemical compounds with potential use against oxidative stress induced by the hydroxyl radical donors in human plasma in vitro. We studied the antiradical capacity of vegetable preparations using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. As oxidative stress may induce changes in hemostasis, our aim included the determination of their effect on three selected hemostatic parameters of plasma, which are three coagulation times: PT (prothrombin time), APTT (activated partial thromboplastin time) and TT (thrombin time). However, none of used vegetable preparations changed APTT, PT or TT compared to the control. The phytochemical composition of the tested preparations was determined by UPLC-ESI-QTOF-MS. In our in vitro experiments, while all five tested preparations had antioxidant potential, the preparation from yellow pattypan squash showed the strongest potential. All cucurbit vegetable preparations inhibited lipid peroxidation. Only zucchini did not have an effect on protein carbonylation and only yellow pattypan squash inhibited thiol oxidation. The antioxidant activity of cucurbits appears to have triggered significant interest in multiple applications, including CVDs (cardiovascular diseases) associated with oxidative stress, which can be treated by supplementation based on these vegetables.

Myelin Basic Protein Phospholipid Complexation Likely Competes with Deimination in Experimental Autoimmune Encephalomyelitis Mouse Model

Multiple sclerosis has complex pathogenesis encompassing a variety of components (immunologic, genetic, and environmental). The autoimmunogenicity against the host's myelin basic protein is a major contributor. An increase in myelin basic protein deimination (a post-translational modification) and a change in phospholipid composition have been associated with multiple sclerosis. The interaction of myelin basic protein with phospholipids in the myelin membrane is an important contributor to the stability and maintenance of proper myelin sheath function. The study of this aspect of multiple sclerosis is an area that has yet to be fully explored and that the present study seeks to understand. Several biochemical methods, a capillary electrophoresis coupled system and mass spectrometry, were used in this study. These methods identified four specific phospholipids complexing with myelin basic protein. We show that lysophosphatidylcholine 18:1 provides a robust competitive effect against hyper-deimination. Our data suggest that lysophosphatidylcholine 18:1 has a different biochemical behavior when compared to other phospholipids and lysophosphatidylcholines 14:0, 16:0, and 18:0.

Differential impact of heat stress on reef-building corals under different light conditions

Heat stress is an environmental factor that regularly challenges the well-being of living organisms. This study aims to examine the physiological changes happening in two reef-building coral species exposed to thermal stress under various light conditions. The two ecologically relevant heatwave scenarios were applied under ambient lights (high irradiance) and reduced light conditions (250 and < 10 μmol photons m^-2 s^-1). Corals were exposed to elevated temperatures of 32°C (plus 6°) for a period of 1 up to 5 days corresponding to heatwaves reported on the Great Barrier Reef (GBR) that were associated with coral bleaching. We monitored changes in the physiological performance of these two coral species by measuring symbionts and corals' physiological parameters including symbiont density, levels of multiple algal pigments (chlorophyll a and peridinin), as well as the changes in the host protein concentration. During the short-term heat stress, both species were with stable physiological performance with the only exception of Stylophora pistillata under ambient lights. These results show that S. pistillata was negatively influenced by a synergistic effect of temperature and high irradiance resulting in the first signs of bleaching after only 24h of thermal stress. Exposure to prolonged thermal stress, characterised with a slower rate of temperature increase, affected both coral species investigated and resulted in bleaching mainly by day 5. Interestingly, severe light reduction (<10 μmol photons m^-2 s^-1) made Acropora millepora corals more thermally sensitive and resulted in earlier signs of bleaching (on day 3). These findings indicate that there was a synergistic effect of very low lights and thermal stress that caused higher levels of bleaching in A. millepora. Our results revealed differential thermal sensitivity for two branching corals exposed to different thermal stress scenarios under various light irradiance conditions, naturally found in their existing habitats. Consequently, global warming may have a differential impact on coral reef biodiversity depending on light availability.

Paradise lost: End-of-century warming and acidification under business-as-usual emissions have severe consequences for symbiotic corals

Despite recent efforts to curtail greenhouse gas emissions, current global emission trajectories are still following the business-as-usual representative concentration pathway (RCP) 8.5 emission pathway. The resulting ocean warming and acidification have transformative impacts on coral reef ecosystems, detrimentally affecting coral physiology and health, and these impacts are predicted to worsen in the near future. In this study, we kept fragments of the symbiotic corals Acropora intermedia (thermally sensitive) and Porites lobata (thermally tolerant) for 7 weeks under an orthogonal design of predicted end-of-century RCP8.5 conditions for temperature and pCO2 (3.5°C and 570 ppm above present-day, respectively) to unravel how temperature and acidification, individually or interactively, influence metabolic and physiological performance. Our results pinpoint thermal stress as the dominant driver of deteriorating health in both species because of its propensity to destabilize coral-dinoflagellate symbiosis (bleaching). Acidification had no influence on metabolism but had a significant negative effect on skeleton growth, particularly when photosynthesis was absent such as in bleached corals or under dark conditions. Total loss of photosynthesis after bleaching caused an exhaustion of protein and lipid stores and collapse of calcification that ultimately led to A. intermedia mortality. Despite complete loss of symbionts from its tissue, P. lobata maintained small amounts of photosynthesis and experienced a weaker decline in lipid and protein reserves that presumably contributed to higher survival of this species. Our results indicate that ocean warming and acidification under business-as-usual CO2 emission scenarios will likely extirpate thermally sensitive coral species before the end of the century, while slowing the recovery of more thermally tolerant species from increasingly severe mass coral bleaching and mortality. This could ultimately lead to the gradual disappearance of tropical coral reefs globally, and a shift on surviving reefs to only the most resilient coral species.

Label-Free Comparative Proteomic Analysis Combined with Laser-Capture Microdissection Suggests Important Roles of Stress Responses in the Black Layer of Maize Kernels

The black layer (BL) is traditionally used as an indicator for kernel harvesting in maize, as it turns visibly dark when the kernel reaches physiological maturity. However, the molecular roles of BL in kernel development have not been fully elucidated. In this work, microscopy images showed that BL began to appear at a growth stage earlier than 10 days after pollination (DAP), and its color gradually deepened to become dark as the development period progressed. Scanning electron microscopy observations revealed that BL is a tissue structure composed of several layers of cells that are gradually squeezed and compressed during kernel development. Laser-capture microdissection (LCM) was used to sample BL and its neighboring inner tissue, basal endosperm transfer layer (BETL), and outer tissue, inner epidermis (IEP), from 20 DAP of kernels. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry profiling (MALDI-TOF MS profiling) detected 41, 104, and 120 proteins from LCM-sampled BL, BETL, and IEP, respectively. Gene ontology (GO) analysis indicated that the 41 BL proteins were primarily involved in the response to stress and stimuli. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis found that the BL proteins were enriched in several defense pathways, such as the ascorbate and aldarate metabolic pathways. Among the 41 BL proteins, six were BL-specific proteins that were only detected from BL. Annotations of five BL-specific proteins were related to stress responses. During kernel development, transcriptional expression of most BL proteins showed an increase, followed by a decrease, and reached a maximum zero to 20 DAP. These results suggest a role for BL in stress responses for protecting filial tissue against threats from maternal sides, which helps to elucidate the biological functions of BL.

A comparison of multifunctional donors of carbon monoxide: Their anticoagulant, antioxidant, anti-aggregatory and cytotoxicity activities in an in vitro model

The study examines the effect of two water-soluble carbon monoxide (CO) donors, CORM-3 and CORM-A1, on selected parameters of oxidative stress and hemostasis in human plasma and blood platelets in vitro. It also compares their activity with that of the lipid-soluble CORM-2. The oxidation of amino acid residues in plasma proteins was evaluated by measuring the amounts of thiol and carbonyl groups. Plasma lipid peroxidation was measured as thiobarbituric acid reactive substance (TBARS) concentration. In addition, three haemostatic parameters of plasma were studied, viz. activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT), and one haemostatic parameter of platelets (platelet aggregation). Treatment with CORM-3 and CORM-A1 (all concentrations from 0.1 to 100 μM) decreased thiol group oxidation induced by H₂O₂/Fe. Incubation with CORM-3 and CORM-A1 also influenced plasma coagulation activity, e.g. CORM-3 and CORM-A1 significantly prolonged TT at the two highest tested concentrations (50 and 100 μM). Only CORM-2 at the highest tested concentration (100 μM) and CORM-3 (50 and 100 μM) reduced platelet aggregation induced by ADP. None of the tested CORMs caused platelet damage. The treatment of various diseases associated with oxidative stress, including cardiovascular diseases, may be enhanced by the administration of CO donors CORM-2 and CORM-3, these being modulators of oxidative stress and hemostasis.

A comparison of the effects of apigenin and seven of its derivatives on selected biomarkers of oxidative stress and coagulation in vitro

Apigenin is a phenolic compound widely present in many fruits, vegetables and herbs. Its name originates from Apium: a genus of the Apiaceae. The aim of the present study was to determine the antioxidant or pro-oxidant properties of apigenin and seven of its derivatives, isolated from the aerial parts of barrel medic (Medicago truncatula) and common wheat (Triticum aestivum), in human plasma treated with a hydroxyl radical donor (OH^•) in vitro. It also examines their influence on the parameters of coagulation. The compounds were found to demonstrate different effects on oxidative stress and coagulation which may be related to differences in their structure. In particular, apigenin 7-O-{2'-O-feruloyl-[β-D-glucuronopyranosyl(1 → 3)]-β-D- glucuronopyranosyl(1 → 2)-O-β-D-glucopyranoside} demonstrates both antioxidant and anticoagulant activities, and may offer the most promise for the prevention and treatment of cardiovascular disorders of all the phenolic compounds tested so far.

Development and validation of a colorimetric method for the quantitative analysis of thioamide derivatives

Thioamides (Thm) have diverse biological activities. This work presents the development and validation of simple, rapid and accurate spectrophotometric method for the analysis of Thm derivatives in pure form and in plasma. This spectrophotometric method has not been used before for determination of Thm. A review of the literature revealed that the monitoring of S^- group assay is based on the reaction with DTNB according to the Ellman method to form a yellow complex which absorbs at 412 nm. To assay the thioamides according to this method it is necessary to make the basic medium have S^- to react with the DTNB. Experimental conditions affecting the color development were studied and optimized. The proposed spectrophotometric procedures were effectively validated with respect to linearity, ranges, precision, accuracy, specificity, robustness, detection and quantification limits. Calibration curves of the formed colored product with DTNB showed good linear relationships over the concentration ranges (0, 50, 100, 500, 1000, 1500 mg/L). The proposed method was successfully applied to the assay of Thm monitoring with good accuracy. The principal advantages of the proposed method were rapidity and suitability for the routine quality control assay of the drug alone and in monitoring form without interference.

Bioactivity-Protected Electrochemiluminescence Biosensor Using Gold Nanoclusters as the Low-Potential Luminophor and Cu2S Snowflake as Co-reaction Accelerator for Procalcitonin Analysis

The expansion of electrochemiluminescence (ECL) technology to immunoassay at the core of care emphasizes all immune molecules will not be inactivated in the analysis process. That poses a major challenge to ECL-based biosensors due to the deoxynucleotide sequences of an antigen or antibody could be oxidized through a route of excessive cyclic potential. Herein, an ultrasensitive ECL biosensor was developed based on a novel bioactivity-protected sensing strategy utilizing Au nanoclusters (Au NCs) as low-potential luminophor for detection of procalcitonin (PCT). Bovine serum albumin (BSA)-templated Au NCs exhibited a low-potential anodic ECL signal in triethylamine (TEA) solution at 0.87 V, where it is suitable for the survival of immune molecules. Taking advantage of good conductivity and high surface area, a Cu₂S snowflake not only functions as a satisfying substrate for connecting immune molecules but also acts as co-reaction accelerator to produce more cationic radicals TEA^•+, which could improve the ECL intensity needed to meet the requirements of trace analysis. Otherwise, HWRGWVC (HC-7) heptapeptide as specific antibody immobilizer for site-oriented fixation was introduced to further maintain the bioactivity of an antibody. In view of the preceding discussion, the obtained biosensor exhibited ultrahigh immune recognition to targets so that the detection limit was as low as an unprecedented value of 2.36 fg/mL, which will be of great significance to the application and development of a biosensor in the future.

Revealing a new fluorescence peak of the enhanced green fluorescent protein using three-dimensional fluorescence spectroscopy

Fluorescent proteins have many applications as biomarkers and biosensors in the medical and biological fields. Their success was largely supported by modifications of the first isolated fluorescent protein, the wild-type Green Fluorescent Protein (wtGFP), which allowed the development of improved variants such as the Enhanced GFP (EGFP). The first reports on EGFP indicated that the protein presented a single form and fluorescence peak, in contrast to the two conformations observed in wtGFP. However, after experimental determination of the crystalline structure of EGFP, two conformations were found, generating questions regarding the relationship between EGFP structure and its spectral characteristics. To resolve the controversy, this study evaluated EGFP 3D fluorescence spectra at lower wavelengths and under distinct conditions (different concentrations, pH and temperatures), revealing the existence of a second fluorescence peak for this protein. It was possible to confirm that the new peak was not a reflection of the intrinsic fluorescence of proteins or an artefact from the 3D fluorescence spectroscopy. It was also shown that the second peak is pH dependent, sensitive to high temperatures and linearly related to EGFP concentration, confirming a direct relationship between the new fluorescence peak and EGFP protein structure. In addition to the revelation of the new EGFP fluorescence peak, this study demonstrated that 3D fluorescence can be used as powerful technique in the discovery of other elusive fluorophores.

Three-dimensional fluorescence spectroscopy as a powerful tool to identify a new fluorescence peak of Enhanced Green Fluorescent Protein (EGFP).

Biological properties of Elaeagnus rhamnoides (L.) A. Nelson twig and leaf extracts

Background

Sea buckthorn (Elaeagnus rhamnoides (L.) A. Nelson, SBT) is a valuable plant because of its medical and therapeutic potential. Different bioactive compounds in SBT berries are of special interest to various researchers. However, not only sea buckthorn berries, but also leaves of this plant (both fresh and dried) contain a lot of nutrients and bioactive compounds, including phenolic compounds. The present study was carried out in order to investigate antioxidant and anticoagulant properties of sea buckthorn twig and leaf extracts (0.5–50 μg/mL) by using various in vitro models. Moreover, the aim of present experiments was to compare the biological activity of SBT leaf extract and SBT twig extract with selected berry extracts (a rich source of phenolic compounds): SBT berry extract (flavonoids being the dominant components), a commercial extract from the berries of Aronia melanocarpa (Aronox®), and a grape seed extract.

Methods

We determined the effect of plant extracts on the oxidative stress using selected markers of this process, i.e. the level of carbonyl groups in proteins. Additionally, we analysed the potential mechanism of modulation of hemostatic properties of human plasma (using selected coagulation times).

Results

SBT twig and leaf extracts were observed to exhibit an antioxidant activity against two strong biological oxidants: hydrogen peroxide (H₂O₂) and H₂O₂/Fe (the donor of hydroxyl radicals), which induced human plasma lipid peroxidation and protein carbonylation. Both extracts also showed anticoagulant properties.

Conclusions

Our present results have demonstrated that extracts from different parts of SBT, especially berries and twigs, in comparison to well-known berries (aronia and grape), may also be viewed as a good source of active substances – antioxidants for pharmacological or cosmetic applications. Moreover, it is very important from an economic point of view to know that there is a possibility of obtaining phenolic compounds not only from the berries or leaves, but also from twigs, which constitute a production waste.

Bioethanol production from sugarcane leaf waste: Effect of various optimized pretreatments and fermentation conditions on process kinetics

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Bioethanol kinetics was investigated under SSA-F, SSA-U, MSA-F and MSA-U conditions.

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Monod, logistic and modified Gompertz models gave R² > 0.97.

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SSA-U pretreated SLW produced 25% more bioethanol than MSA-U.

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No difference was observed between filtered and unfiltered enzymatic hydrolysate.

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SLW residue showed a suitable protein and fat content for animal feed.

This study examines the kinetics of S. cerevisiae BY4743 growth and bioethanol production from sugarcane leaf waste (SLW), utilizing two different optimized pretreatment regimes; under two fermentation modes: steam salt-alkali filtered enzymatic hydrolysate (SSA-F), steam salt-alkali unfiltered (SSA-U), microwave salt-alkali filtered (MSA-F) and microwave salt-alkali unfiltered (MSA-U). The kinetic coefficients were determined by fitting the Monod, modified Gompertz and logistic models to the experimental data with high coefficients of determination R² > 0.97. A maximum specific growth rate (μ_max) of 0.153 h⁻¹ was obtained under SSA-F and SSA-U whereas, 0.150 h⁻¹ was observed with MSA-F and MSA-U. SSA-U gave a potential maximum bioethanol concentration (P_m) of 31.06 g/L compared to 30.49, 23.26 and 21.79 g/L for SSA-F, MSA-F and MSA-U respectively. An insignificant difference was observed in the μ_max and P_m for the filtered and unfiltered enzymatic hydrolysate for both SSA and MSA pretreatments, thus potentially reducing a unit operation. These findings provide significant insights for process scale up.

MnCO3 as a New Electrochemiluminescence Emitter for Ultrasensitive Bioanalysis of β-Amyloid1-42 Oligomers Based on Site-Directed Immobilization of Antibody

In this work, an electrochemiluminescence (ECL) immunosensor utilizing MnCO₃ nanospheres as a novel ECL luminophor and the HWRGWVC (HC-7) heptapeptide as an efficient antibody capturer for site-directed immobilization with high affinity was proposed. MnCO₃ nanospheres prepared by a homogeneous precipitation method exhibited high ECL efficiency, low toxicity, favorable biocompatibility, and excellent stability. After the functionalization of polydimethyldiallylammonium chloride (PDDA), the obtained MnCO₃/PDDA could combine with gold nanoparticles (Au NPs) via electrostatic interaction (MnCO₃/PDDA/Au). Besides, HC-7 as a small peptide ligand has demonstrated an ability to bind the Fc portion of an antibody with high affinity. Because the end of HC-7 is a cysteine, it can connect to MnCO₃/PDDA/Au via a Au-S bond. Then, the antibody could be effectively captured by HC-7 through specific interaction with a better maintained activity than traditional coupling reaction. To verify the practicability of the constructed immunosensor, β-amyloid_1-42 oligomers (Aβ) were employed as an analyte. On the basis of the above points, the immunosensor performed favorable ECL property to Aβ concentrations in a wide linear range (0.1 pg/mL to 10 ng/mL) with a low detection limit (19.95 fg/mL). With excellent repeatability, selectivity, and stability, this method opened up a new avenue for realizing the ultrasensitive detection of Aβ and other biomarkers in a real sample analysis.

The molecular structure of an epoxide hydrolase from Trichoderma reesei in complex with urea or amide-based inhibitors

Epoxide hydrolases (EHs) are enzymes involved in the metabolism of endogenous and exogenous epoxides, and the development of EH inhibitors has important applications in the medicine. In humans, EH inhibitors are being tested in the treatment of cardiovascular diseases and show potent anti-inflammatory effects. EH inhibitors are also considerate promising molecules against infectious diseases. EHs are functionally very well studied, but only a few members have its three-dimensional structures characterized. Recently, a new EH from the filamentous fungi Trichoderma reseei (TrEH) was reported, and a series of urea or amide-based inhibitors were identified. In this study, we describe the crystallographic structures of TrEH in complex with five different urea or amide-based inhibitors with resolutions ranging from 2.6 to 1.7 Å. The analysis of these structures reveals the molecular basis of the inhibition of these compounds. We could also observe that these inhibitors occupy the whole extension of the active site groove and only a few conformational changes are involved. Understanding the structural basis EH interactions with different inhibitors might substantially contribute for the study of fungal metabolism and in the development of novel and more efficient antifungal drugs against pathogenic Trichoderma species.

Isorhamnetin and its new derivatives isolated from sea buckthorn berries prevent H2O2/Fe - Induced oxidative stress and changes in hemostasis

The objective of this study is to investigate the biological effects of phenolic compounds extracted from the sea buckthorn berries on oxidative stress and hemostasis. The sea buckthorn (Elaeagnus rhamnoides (L.) A. Nelson) berries are rich in flavonoids and non-polar compounds. In this study, the activity of the phenolic fraction from the sea buckthorn berries was evaluated in vitro in comparison with three phenolic compounds: isorhamnetin (compound 1) and its two new derivatives: compound 2 (isorhamnetin 3-O-beta-glucoside-7-O-alfa-rhamnoside) and compound 3 (isorhamnetin 3-O-beta-glucoside-7-O-alfa-(3"'-isovaleryl)-rhamnoside). The impact of these phenolic compounds and the phenolic fraction against the effect of the donor of hydroxyl radicals - H₂O₂/Fe on proteins and lipids in human plasma was measured. Additionally, the aim of the study was to determine the effect of these phenolic compounds and the phenolic fraction on various typical hemostasis parameters. Our results show that the used derivatives of isorhamnetin possess different biological properties (e.g. antioxidant, anti-platelet and anticoagulant). The tested compounds can be seen as new natural beneficial compounds to be used in prevention and treatment of cardiovascular diseases.

Ultraviolet/persulfate (UV/PS) pretreatment of typical natural organic matter (NOM): Variation of characteristics and control of membrane fouling

The effects of ultraviolet/persulfate (UV/PS) pretreatment on ultrafiltration (UF) membrane fouling caused by typical natural organic matter (NOM) fractions including humic acid (HA), sodium alginate (SA), and bovine serum albumin (BSA) were investigated. UF membrane fouling during the filtration of different NOM fractions after UV/PS pretreatment was compared through the evaluation of normalized membrane flux decline and membrane fouling reversibility. The fouling mitigation mechanisms were investigated through the characterization of ultraviolet absorbance (UV₂₅₄), dissolved organic matter, zeta potential, particle size distribution, fluorescence excitation-emission matrix spectra, and fitness of four classic fouling models. Furthermore, the fouled membranes were characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy. The results showed that UV/PS pretreatment significantly alleviated membrane fouling caused by HA, SA, and HA-SA-BSA mixture, and the fouling control performance improved at high PS doses. However, either UV alone or UV/PS pretreatment at low PS dose (10 mg/L) significantly aggravated BSA fouling with the normalized flux at the end of first filtration cycle being 8% and 15%, respectively. The increased particle size of BSA after UV/PS pretreatment was attributed to the formation of aggregates, which mainly accumulated in membrane pores and aggravated membrane fouling. Modeling results suggest that the mitigation of membrane fouling derived from SA and mixed organic fractions was primarily ascribed to the control of cake filtration, while the mitigation of HA fouling was attributed to the declined contribution of standard blocking.

Polydopamine/Transferrin Hybrid Nanoparticles for Targeted Cell-Killing

Polydopamine can form biocompatible particles that convert light into heat. Recently, a protocol has been optimized to synthesize polydopamine/protein hybrid nanoparticles that retain the biological function of proteins, and combine it with the stimuli-induced heat generation of polydopamine. We have utilized this novel system to form polydopamine particles, containing transferrin (PDA/Tf). Mouse melanoma cells, which strongly express the transferrin receptor, were exposed to PDA/Tf nanoparticles (NPs) and, subsequently, were irradiated with a UV laser. The cell death rate was monitored in real-time. When irradiated, the melanoma cells exposed to PDA/Tf NPs underwent apoptosis, faster than the control cells, pointing towards the ability of PDA/Tf to mediate UV-light-induced cell death. The system was also validated in an organotypic, 3D-printed tumor spheroid model, comprising mouse melanoma cells, and the exposure and subsequent irradiation with UV-light, yielded similar results to the 2D cell culture. The process of apoptosis was found to be targeted and mediated by the lysosomal membrane permeabilization. Therefore, the herein presented polydopamine/protein NPs constitute a versatile and stable system for cancer cell-targeting and photothermal apoptosis induction.

Substrate and inhibitor selectivity, and biological activity of an epoxide hydrolase from Trichoderma reesei

Epoxide hydrolases (EHs) are present in all living organisms and catalyze the hydrolysis of epoxides to the corresponding vicinal diols. EH are involved in the metabolism of endogenous and exogenous epoxides, and thus have application in pharmacology and biotechnology. In this work, we describe the substrates and inhibitors selectivity of an epoxide hydrolase recently cloned from the filamentous fungus Trichoderma reesei QM9414 (TrEH). We also studied the TrEH urea-based inhibitors effects in the fungal growth. TrEH showed high activity on radioative and fluorescent surrogate and natural substrates, especially epoxides from docosahexaenoic acid. Using a fluorescent surrogate substrate, potent inhibitors of TrEH were identified. Interestingly, one of the best compounds inhibit up to 60% of T. reesei growth, indicating an endogenous role for TrEH. These data make TrEH very attractive for future studies about fungal metabolism of fatty acids and possible development of novel drugs for human diseases.

Phenolic fraction and nonpolar fraction from sea buckthorn leaves and twigs: chemical profile and biological activity

AIM

The main objective of our studies was to determine the chemical composition and biological activities (antioxidant and anticoagulant properties) of two standardized phenolic fractions from sea buckthorn twig and leaf, and two standardized nonpolar fractions from twig and leaf in human plasma in vitro.

MATERIAL & METHODS

Appropriately prepared extracts from sea buckthorn twigs and leaves were used. Markers of oxidative stress and hemostasis were determined in this work.

RESULTS

The reduction of plasma lipid peroxidation induced by H₂O₂/Fe was observed for two fractions from twig. Analysis of the effect on the coagulation properties of plasma demonstrated that the nonpolar fraction from twig and the phenolic fraction from leaf, significantly prolonged the activated partial thromboplastin time and the prothrombin time, respectively.

CONCLUSION

Sea buckthorn twig and leaf are new promising plant materials in the prophylaxis and treatment of cardiovascular disorders.

A novel role of C-terminus in introducing a functionally flexible structure critical for the biological activity of botulinum neurotoxin

Botulinum neurotoxin (BoNT) is responsible for botulism, a clinical condition resulting in flaccid muscle paralysis and potentially death. The light chain is responsible for its intracellular toxicity through its endopeptidase activity. Available crystal structures of BoNT/A light chains (LCA) are based on various truncated versions (tLCA) of the full-length LCA (fLCA) and do not necessarily reflect the true structure of LCA in solution. The understanding of the mechanism of action, longevity of intoxication, and an improved development of endopeptidase inhibitors are dependent on first having a better insight into the structure of LCA in solution. Using an array of biophysical techniques, we report that the fLCA structure is significantly more flexible than tLCA in solution, which may be responsible for its dramatically higher enzymatic activity. This seems to be achieved by a much stronger, more rapid binding to substrate (SNAP-25) of the fLCA compared to tLCA. These results suggest that the C-terminus of LCA plays a critical role in introducing a flexible structure, which is essential for its biological function. This is the first report of such a massive structural role of the C-terminus of a protein being critical for maintaining a functional state.