Neuron navigators: A novel frontier with physiological and pathological implications.

Neuron navigators are microtubule plus-end tracking proteins containing basic and serine rich regions which are encoded by neuron navigator genes (NAVs). Neuron navigator proteins are essential for neurite outgrowth, neuronal migration, and overall neurodevelopment along with some other functions as well. The navigator proteins are substantially expressed in the developing brain and have been reported to be differentially expressed in various tissues at different ages. Over the years, the research has found neuron navigators to be implicated in a spectrum of pathological conditions such as developmental anomalies, neurodegenerative disorders, neuropathic pain, anxiety, cancers, and certain inflammatory conditions. The existing knowledge about neuron navigators remains sparse owing to their differential functions, undiscovered modulators, and unknown molecular mechanisms. Investigating the possible role of neuron navigators in various physiological processes and pathological conditions pose as a novel field that requires extensive research and might provide novel mechanistic insights and understanding of these aspects.

Mitochondria-localized AMPK responds to local energetics and contributes to exercise and energetic stress-induced mitophagy.

Mitochondria form a complex, interconnected reticulum that is maintained through coordination among biogenesis, dynamic fission, and fusion and mitophagy, which are initiated in response to various cues to maintain energetic homeostasis. These cellular events, which make up mitochondrial quality control, act with remarkable spatial precision, but what governs such spatial specificity is poorly understood. Herein, we demonstrate that specific isoforms of the cellular bioenergetic sensor, 5' AMP-activated protein kinase (AMPKα1/α2/ß2/γ1), are localized on the outer mitochondrial membrane, referred to as mitoAMPK, in various tissues in mice and humans. Activation of mitoAMPK varies across the reticulum in response to energetic stress, and inhibition of mitoAMPK activity attenuates exercise-induced mitophagy in skeletal muscle in vivo. Discovery of a mitochondrial pool of AMPK and its local importance for mitochondrial quality control underscores the complexity of sensing cellular energetics in vivo that has implications for targeting mitochondrial energetics for disease treatment.

Ethosomes as a carrier for transdermal drug delivery system: methodology and recent developments.

Transdermal drug delivery systems (TDDS) have received significant attention in recent years. TDDS are flexible systems that transport active components to the skin for either localized or systemic delivery of drugs through the skin. Among the three main layers of skin, the outermost layer, called the stratum corneum (SC), prevents the entry of water-loving bacteria and drugs with a high molecular weight. The challenge lies in successfully delivering drugs through the skin, which crosses the stratum corneum. The popularity of lipid-based vesicular delivery systems has increased in recent years due to their ability to deliver both hydrophilic and hydrophobic drugs. Ethosomes are specialized vesicles made of phospholipids that can store large amounts of ethanol. Ethosome structure and substance promote skin permeability and bioavailability. This article covers ethosome compositions, types, medication delivery techniques, stability, and safety. In addition to this, an in-depth analysis of the employment of ethosomes in drug delivery applications for a wide range of diseases has also been discussed. This review article highlights different aspects of ethosomes, such as their synthesis, characterization, marketed formulation, recent advancements in TDDS, and applications.

Characterization of Sulfur Oxidizing Bacteria and Their Effect on Growth Promotion of Brassica napus L.

Oil seeds sector is one of the major dynamic components of the agriculture world. Oil seeds such as canola (Brassica napus) require a higher quantity of sulfur (S), which is supplied through inorganic fertilizers. However, the overapplication of agro-chemicals to get higher yields of crops is harming the soil health. Therefore, the application of bacterial cultures with plant growth-promoting activity as biofertilizers ensures soil health maintenance and enhances crop productivity. To achieve this aim, the present research was initiated by procuring three sulfur-oxidizing bacteria (SOBs), namely, SOB 5, SOB 10, and SOB 38, from the Microbiology Department, PAU. In the initial assessment, all three SOB cultures showed resilience to pesticide toxicity at the recommended dosage, with the exception of ridomil. These cultures were later characterized morphologically, biochemically, and at the molecular level using 16s rRNA resulting in their identification as Enterobacter ludwigii strain Remi_9 (SOB 5), Enterobacter hormaechei strain AUH-ENM30 (SOB 10), and Bacillus sp. 5BM21Y12 (SOB 38). Functional characterization of these SOB cultures revealed their ability to exhibit multifarious plant growth-promoting traits. Bacillus sp. 5BM21Y12 showed greater functional activity, including high P solubilization (14.903 µg/mL), IAA production (44.28 µg/mL), siderophore production (13.89 µg/mL), sulfate ion production (0.127 mM), ammonia excretion (2.369 µg/mL), and Zn solubilization (22.62 mm). Based on the results of functional and molecular characterization, Bacillus sp. 5BM21Y12 was selected for field trials by formulating different treatments. Composite treatment, T8 (100% S + Bacillus sp. + pesticides) significantly enhanced growth parameters (plant height, root, and shoot biomass), yield attributes (siliqua length, test weight, number of siliqua/plant), yield parameter (total biomass and seed yield), quality parameter (crude protein and oil) as compared to all other sole treatments employed in the field. A combined application of non-pathogenic Bacillus sp. 5BM21Y12, with good functional activity enhanced yield of crop due to synergistic and additive interaction with fertilizer/pesticides. As biofertilizer application reduces the input of pesticides/fertilizers new inoculant formulations with cell protectors and the development of compatible pesticides should be searched to assure the benefits of integrated treatment.

Investigating the presence of dioxins in drinking water: implications for public health.

The presence of highly toxic dioxins, specifically polychlorinated dibenzo-p-dioxins (PCDDs), in drinking water is a matter of great concern due to their long-lasting nature and harmful effects. In this study, we detected three out of the five dioxin congeners: 2, 3, 7, 8-tetrachlorodibenzodioxin (TCDD), 1, 2, 3, 7, 8-pentachlorodibenzo-p-dioxin (PeCDD), and octachlorodibenzo-p-dioxin (OCDD). The investigation revealed that three dioxins were present in water samples of winter season, while TCDD and OCDD were found in the summer season. The geometric mean concentrations of PCDDs were 229.9 ng/L (winter) and 108.4 ng/L (summer), exceeded the maximum contaminant level of 30 pg/L set by the USEPA in surface water. The estimated daily intake of PCDDs for residents through drinking water was 273.97 ng-WHO2005-TEQ/kg/days during winter and 78.875 ng-WHO2005-TEQ/kg/days during summer. Our study emphasizes the urgent need for further research on persistent organic pollutants in drinking water to safeguard public health and community well-being.

Antibiotic disposal challenges in India: investigating causes and effects.

Antibiotic resistance has become a global problem and India emerges as a key battlefield in the fight against it. While inappropriate use of antibiotics is well known, the review article deliberates a less recognized yet equally perilous facet of the crisis i.e. improper antibiotic disposal. An investigation of the sources of antibiotic pollution in Indian water bodies identifies discharge of pharmaceutical effluents, hospital waste, and agricultural runoff as major contributing factors. Furthermore, it discusses the repercussions of antibiotic pollution including those relating to human health, aquatic ecosystems, and antibiotic resistance. Reviewing the causes and consequences of improper antibiotic disposal practices emphasizes the necessity of rethinking antibiotic waste management practices. The review highlights the need for stringent rules and increased awareness, while also discussing the emerging technologies and strategies to mitigate the risks of antibiotic disposal in India.

Pten associates with important gene regulatory network to fine-tune Müller glia-mediated zebrafish retina regeneration.

Unlike mammals, zebrafish possess a remarkable ability to regenerate damaged retina after an acute injury. Retina regeneration in zebrafish involves the induction of Müller glia-derived progenitor cells (MGPCs) exhibiting stem cell-like characteristics, which are capable of restoring all retinal cell-types. The induction of MGPC through Müller glia-reprograming involves several cellular, genetic and biochemical events soon after a retinal injury. Despite the knowledge on the importance of Phosphatase and tensin homolog (Pten), which is a dual-specificity phosphatase and tumor suppressor in the maintaining of cellular homeostasis, its importance during retina regeneration remains unknown. Here, we explored the importance of Pten during zebrafish retina regeneration. The Pten gets downregulated upon retinal injury and is absent from the MGPCs, which is essential to trigger Akt-mediated cellular proliferation essential for retina regeneration. We found that the downregulation of Pten in the post-injury retina accelerates MGPCs formation, while its overexpression restricts the regenerative response. We observed that Pten regulates the proliferation of MGPCs not only through Akt pathway but also by Mmp9/Notch signaling. Mmp9-activity is essential to induce the proliferation of MGPCs in the absence of Pten. Lastly, we show that expression of Pten is fine-tuned through Mycb/histone deacetylase1 and Tgf-ß signaling. The present study emphasizes on the stringent regulation of Pten and its crucial involvement during the zebrafish retina regeneration.

Anti-SARS-CoV-2 and anticoagulant properties of Pentacta pygmaea fucosylated chondroitin sulfate depend on high molecular weight structures.

Fucosylated chondroitin sulfate (FucCS) is a unique marine glycosaminoglycan that exhibits diverse biological functions, including antiviral and anticoagulant activity. In previous work, the FucCS derived from Pentacta pygmaea (PpFucCS) showed moderate anticoagulant effect but high inhibitory activity against the Wuhan strain of severe acute respiratory syndrome coronavirus (SARS-CoV-2). In this study, we perform free-radical depolymerization of PpFucCS by the copper-based Fenton method to generate low molecular weight (MW) oligosaccharides. PpFucCS oligosaccharides were structurally analyzed by 1H nuclear magnetic resonance spectroscopy and were used to conduct structure-activity relationship studies regarding their effects against SARS-CoV-2 and clotting. Anticoagulant properties were measured by activated partial thromboplastin time, protease (factors Xa and IIa) inhibition by serine protease inhibitors (antithrombin [AT] and heparin cofactor II [HCII]), and competitive surface plasmon resonance (SPR) assay using AT, HCII, and IIa. Anti-SARS-CoV-2 properties were measured by the concentration-response inhibitory curves of HEK-293T-human angiotensin-converting enzyme-2 cells infected with a baculovirus pseudotyped SARS-CoV-2 Delta variant spike (S)-protein and competitive SPR assays using multiple S-proteins (Wuhan, N501Y [Alpha], K417T/E484K/N501Y [Gamma], L542R [Delta], and Omicron [BA.2 subvariant]). Cytotoxicity of native PpFucCS and oligosaccharides was also assessed. The PpFucCS-derived oligosaccharide fraction of the highest MW showed great anti-SARS-CoV-2 Delta activity and reduced anticoagulant properties. Results have indicated no cytotoxicity and MW dependency on both anti-SARS-CoV-2 and anticoagulant effects of PpFucCS, as both actions were reduced accordingly to the MW decrease of PpFucCS. Our results demonstrate that the high-MW structures of PpFucCS is a key structural element to achieve the maximal anti-SARS-CoV-2 and anticoagulant effects.

Role of bacterial efflux pump proteins in antibiotic resistance across microbial species.

Efflux proteins are transporter molecules that actively pump out a variety of substrates, including antibiotics, from cells to the environment. They are found in both Gram-positive and Gram-negative bacteria and eukaryotic cells. Based on their protein sequence homology, energy source, and overall structure, efflux proteins can be divided into seven groups. Multidrug efflux pumps are transmembrane proteins produced by microbes to enhance their survival in harsh environments and contribute to antibiotic resistance. These pumps are present in all bacterial genomes studied, indicating their ancestral origins. Many bacterial genes encoding efflux pumps are involved in transport, a significant contributor to antibiotic resistance in microbes. Efflux pumps are widely implicated in the extrusion of clinically relevant antibiotics from cells to the extracellular environment and, as such, represent a significant challenge to antimicrobial therapy. This review aims to provide an overview of the structures and mechanisms of action, substrate profiles, regulation, and possible inhibition of clinically relevant efflux pumps. Additionally, recent advances in research and the pharmacological exploitation of efflux pump inhibitors as a promising intervention for combating drug resistance will be discussed.

The Sea Cucumber Thyonella gemmata Contains a Low Anticoagulant Sulfated Fucan with High Anti-SARS-CoV-2 Actions against Wild-Type and Delta Variants.

In this work, we isolated two new sulfated glycans from the body wall of the sea cucumber Thyonella gemmata: one fucosylated chondroitin sulfate (TgFucCS) (17.5 ± 3.5% kDa) and one sulfated fucan (TgSF) (383.3 ± 2.1% kDa). NMR results showed the TgFucCS backbone composed of [→3)-ß-N-acetylgalactosamine-(1→4)-ß-glucuronic acid-(1→] with 70% 4-sulfated and 30% 4,6-disulfated GalNAc units and one-third of the GlcA units decorated at the C3 position with branching α-fucose (Fuc) units either 4-sulfated (65%) or 2,4-disulfated (35%) and the TgSF structure composed of a tetrasaccharide repeating unit of [→3)-α-Fuc2,4S-(1→2)-α-Fuc4S-(1→3)-α-Fuc2S-(1→3)-α-Fuc2S-(1→]n. Inhibitory properties of TgFucCS and TgSF were investigated using SARS-CoV-2 pseudovirus coated with S-proteins of the wild-type (Wuhan-Hu-1) or the delta (B.1.617.2) strains and in four different anticoagulant assays, comparatively with unfractionated heparin. Molecular binding to coagulation (co)-factors and S-proteins was investigated by competitive surface plasmon resonance spectroscopy. Among the two sulfated glycans tested, TgSF showed significant anti-SARS-CoV-2 activity against both strains together with low anticoagulant properties, indicating a good candidate for future studies in drug development.

A review on control and abatement of soil pollution by heavy metals: Emphasis on artificial intelligence in recovery of contaminated soil.

"Save Soil Save Earth" is not just a catchphrase; it is a necessity to protect soil ecosystem from the unwanted and unregulated level of xenobiotic contamination. Numerous challenges such as type, lifespan, nature of pollutants and high cost of treatment has been associated with the treatment or remediation of contaminated soil, whether it be either on-site or off-site. Due to the food chain, the health of non-target soil species as well as human health were impacted by soil contaminants, both organic and inorganic. In this review, the use of microbial omics approaches and artificial intelligence or machine learning has been comprehensively explored with recent advancements in order to identify the sources, characterize, quantify, and mitigate soil pollutants from the environment for increased sustainability. This will generate novel insights into methods for soil remediation that will reduce the time and expense of soil treatment.

Enhancement of bacterial cellulose production by ethanol and lactic acid by using Gluconacetobacter kombuchae.

The current study intended to analyze the impact of ethanol and lactic acid on the bacterial cellulose yield as well as physicochemical and mechanical properties, by using Gluconacetobacter kombuchae. The optimization of ethanol and lactic acid concentration has been done by using one-way ANOVA. Both the supplements significantly enhance the yield of bacterial cellulose (BC) as compared to the standard Hestrin-Schramm medium (control). Optimization leads to significant increase in BC yield as compared to the control, i.e., the addition, of optimized concentration of lactic acid (0.6%) increases the yield from (0.78 ± 0.026) g to (4.89 ± 0.020) g dry weight, and optimized concentration of ethanol (1%) increases the yield from (0.73 ± 0.057) g to (3.7 ± 0.01) g dry weight. Various physicochemical and mechanical properties of BC films produced in different media (i.e., HS, HS + Ethanol, and HS + Lactic acid), such as the crystallinity, structure, tensile strength, strain at break, Young's modulus, and water holding capacity, were also examined, by employing various techniques such as SEM, FTIR, XRD, etc. BC produced in medium supplemented with the optimum concentration of both the additives were found to possesses higher porosity. Though, slight decline in crystallinity was observed. But the tensile strength and strain at break, were upgraded 1.5-2.5 times, 2-2.5 times, respectively. This article attempted to present a method for enhancing BC yields and characteristics that may lead to more widespread and cost-effective use of this biopolymer.

Assessment of multidrug-resistant profile, multi-locus sequence typing and efflux pump activity in Salmonella Typhimurium isolated from hospital sewage.

Salmonella enterica serovar Typhimurium is becoming a leading cause of gastroenteritis and mortality. The use of antibiotics has increased natural resistance of S. Typhimurium to antibiotics. This study aims to isolate and characterize multi-drug-resistant (MDR) Salmonella strains from hospital sewage samples in Bhopal City, central India. The MDR isolates were characterized by molecular identification, antimicrobial resistance patterns, multi-locus sequence typing, and efflux pump activity. Specific genes (hilA, stn, invA, typh, and iroB) were used to confirm S. Typhimurium isolates. The Kirbey-Bauer method was employed to profile antimicrobial resistance using 20 antibiotics. Multi-locus sequence typing confirmed S. Typhimurium using seven housekeeping genes (aroC, dnaN, hemD, hisD, purE, sucA, and thr). Out of five strains, only four were confirmed as S. Typhimurium during MLST analysis. Efflux pump activity was determined using the ethidium bromide (EtBr) cartwheel test. Of the 160 isolates, 38 were presumptively confirmed as S. Typhimurium based on biochemical characterization, and only five MDR Salmonella strains were selected for their resistance against most antibiotics. Efflux pump activity revealed that five out of the four MDR isolates did not retain EtBr inside the cells, indicating pronounced efflux activity. Additionally, the isolated strains showed a specific correlation between the antimicrobial phenotypes and genotypes. The results of this study provide a better understanding of the characterization of S. Typhimurium serotype in Bhopal City. Future studies should focus on understanding changing antimicrobial resistance patterns, pathogenicity, and the genetic background of Salmonella serotypes. Further surveillance activities for antimicrobial-resistant Salmonella in different environmental sources should be prioritized.

Rehabilitation of Dentofacial Asymmetry Secondary to Unilateral Temporomandibular Joint Ankylosis with Dual Distraction and Fixed Orthodontics - Stability at Three-year Follow-up.

Optimal rehabilitation of asymmetric dentofacial deformity secondary to unilateral temporomandibular joint (TMJ) ankylosis is often a challenge. The purpose of this case series is to present an insight into esthetic, occlusal and functional rehabilitation of two patients with varying degree of asymmetric Class II dentofacial deformities secondary to long-standing unilateral TMJ ankylosis. The patients were treated with one-stage surgical protocol employing simultaneous dual distraction technique along with interpositional arthroplasty. Dual distraction technique entailed the simultaneous use of two distractors which allowed for proper control of proximal condylar segment during the course of distraction and lowering the risk of ankylosis recurrence. Thereafter, comprehensive fixed orthodontic mechanotherapy involving the use of temporary anchorage devices was instituted to align and level the compensated dentition. Post-treatment records showed significant improvements in skeletal disharmony and functional stability with good functional occlusion. At the three-year follow-up, the morphological and functionally acceptable results were reasonably well-maintained, with no signs of relapse. Through the two cases reported here, we would like to highlight that one-stage concurrent arthroplasty and dual distraction technique is a safe, stable, and reliable approach for surgical and functional rehabilitation of an adult asymmetric dentofacial deformity secondary to unilateral TMJ ankylosis. Meticulously executed comprehensive orthodontic manipulations involving use of acrylic bite-blocks, elastic traction, and temporary skeletal anchorage device play a crucial role in enhancing the final occlusal outcomes.

Marker trait association for biological nitrogen fixation traits in an interspecific cross of chickpea (Cicer arietinum × Cicer reticulatum).

A set of 165 Recombinant inbred lines (RILs) derived from an interspecific cross of chickpea was used to identify QTLs for key biological nitrogen fixation (BNF) traits. The phenotyping of BNF and related traits was done at two different agroclimatic zones viz., Central plain zone (Ludhiana) and Sub-Mountainous undulating zone (Gurdaspur) for 2 consecutive rabi seasons (2018-2020). Wild parent C. reticulatum ILWC292 showed significantly high performance in terms of biological nitrogen fixation (BNF) traits over the cultivated C. arietinum GPF-2. The triple interaction of genotypes × locations × years was significant (p 0.05) for all BNF traits in parental lines. Highly significant positive correlation was obtained between grain yield and key growth and symbiotic parameters at both the sites. Phenotypic analysis revealed nodule dry weight and leghaemoglobin content as key traits for BNF efficiency and contrasting DNA bulks were constituted on the basis of these traits. Out of 535 SSR markers, 139 exhibited polymorphism between the parental lines on polyacrylamide gel electrophoresis. A total of 30 SSR markers showed polymorphism between the higher and lower bulks for nodule dry weight and leghaemoglobin content. Out of these, 20 SSRs did not show any segregation distortion in RIL population as determined by chi square analysis (p < 0.05) and were used for quantitative trait loci (QTL) analysis. Using QTL cartographer, markers- CAGM02697, CAGM09835, CAGM09777, CAGM09227, CAGM09021, CAGM08679 were found linked with QTLs for BNF. These markers can be validated further for identification of genes for BNF traits and marker assisted selection in chickpea. To the best of our knowledge this is the first report on identification of genomic regions associated with key BNF traits in chickpea across different agro-climatic zones. Supplementary information: The online version contains supplementary material available at 10.1007/s12298-023-01335-3.

Sustainable utilization of Citrus limetta peel for obtaining pectin and its application in cookies as a fat replacer.

In this study, a five-factorial central composite design was employed to optimize pectin extraction from novel source, through ultrasound-assisted extraction. A 35.58% yield was obtained under optimized conditions of pH 1.0, solid (g): liquid (mL) ratio 1:24, amplitude 84.2 Hz, duty cycle 23 s/30 s, and time 30 min. The equivalent weight, methoxyl content, anhydrouronic acid content, degree of esterification, water-holding capacity, and oil-holding capacity of the extracted pectin were 796.40 ± 2.07, 8.29 ± 0.38%, 71.32 ± 0.54%, 64.66 ± 2.08%, 8.04 ± 0.10 g water/g pectin, and 2.24 ± 030 g oil/g pectin, respectively. The chemical profile of the extracted pectin was assessed with FTIR and NMR analyses. The extracted pectin was utilized as a butter substitute in cookies. Up to 30% butter in cookies could be replaced with the extracted pectin without altering the sensory and physicochemical properties. Overall, results of presented work suggest that using waste-derived pectin as a fat substitute in cookies offers a sustainable and health-promoting approach for converting waste into wealth.

Microwave-assisted valorization and characterization of Citrus limetta peel waste into pectin as a perspective food additive.

Machine learning techniques were employed to evaluate the effect of process parameters viz. microwave power (100 W, 300 W, 600 W); pH (1, 1.5, 2); and microwave time (the 60 s, 120 s, 180 s) on the pectin yield from Citrus limetta peel. A fourth-order polynomial function of 66.60 scales was used by the Support Vector Regression (SVR) model at an epsilon (ε) value of 0.003. The co-efficient of determination (R2) and root mean square error-values for training data and test data were 0.984; 0.77 and 0.993; 0.66 respectively. At optimized conditions, microwave power 600 W, pH 1, and time 180 s the best yield of 32.75% was obtained. The integrity of pectin skeletal was confirmed with FTIR and 1H NMR spectrums. The physicochemical analysis revealed that CLP is a high-methoxyl pectin (HMP) with a 63.20 ± 0.88% degree of esterification, 798.45 ± 26.15 equivalent weight, 8.06 ± 0.62% methoxyl content, 67.93 ± 3.36 AUA content, 6.27 ± 0.27 g water/g pectin WHC, 2.68 ± 0.20 g oil/g pectin OHC, low moisture, ash and protein content of 6.85 ± 0.10%, 3.87 ± 0.10% and 2.61 ± 0.06% respectively, which can be utilized as a food additive. Therefore, pectin extraction from Citrus limetta peel using a greener technique like MAE is an eco-friendly, time-saving approach to transform waste into a versatile food additive.

Structural and kinetic analyses of holothurian sulfated glycans suggest potential treatment for SARS-CoV-2 infection.

Certain sulfated glycans, including those from marine sources, can show potential effects against SARS-CoV-2. Here, a new fucosylated chondroitin sulfate (FucCS) from the sea cucumber Pentacta pygmaea (PpFucCS) (MW ∼10-60 kDa) was isolated and structurally characterized by NMR. PpFucCS is composed of {→3)-ß-GalNAcX-(1→4)-ß-GlcA-[(3→1)Y]-(1→}, where X = 4S (80%), 6S (10%) or nonsulfated (10%), Y = α-Fuc2,4S (40%), α-Fuc2,4S-(1→4)-α-Fuc (30%), or α-Fuc4S (30%), and S = SO3-. The anti-SARS-CoV-2 activity of PpFucCS and those of the FucCS and sulfated fucan isolated from Isostichopus badionotus (IbFucCS and IbSF) were compared with that of heparin. IC50 values demonstrated the activity of the three holothurian sulfated glycans to be ∼12 times more efficient than heparin, with no cytotoxic effects. The dissociation constant (KD) values obtained by surface plasmon resonance of the wildtype SARS-CoV-2 spike (S)-protein receptor-binding domain (RBD) and N501Y mutant RBD in interactions with the heparin-immobilized sensor chip were 94 and 1.8 × 103 nM, respectively. Competitive surface plasmon resonance inhibition analysis of PpFucCS, IbFucCS, and IbSF against heparin binding to wildtype S-protein showed IC50 values (in the nanomolar range) 6, 25, and 6 times more efficient than heparin, respectively. Data from computational simulations suggest an influence of the sulfation patterns of the Fuc units on hydrogen bonding with GlcA and that conformational change of some of the oligosaccharide structures occurs upon S-protein RBD binding. Compared with heparin, negligible anticoagulant action was observed for IbSF. Our results suggest that IbSF may represent a promising molecule for future investigations against SARS-CoV-2.

Inhibition of SARS-CoV-2 wild-type (Wuhan-Hu-1) and Delta (B.1.617.2) strains by marine sulfated glycans.

The Coronavirus disease pandemic has steered the global therapeutic research efforts toward the discovery of potential anti-severe acute respiratory syndrome coronavirus (SARS-CoV-2) molecules. The role of the viral spike glycoprotein (S-protein) has been clearly established in SARS-CoV-2 infection through its capacity to bind to the host cell surface heparan sulfate proteoglycan (HSPG) and angiotensin-converting enzyme-2. The antiviral strategies targeting these 2 virus receptors are currently under intense investigation. However, the rapid evolution of the SARS-CoV-2 genome has resulted in numerous mutations in the S-protein posing a significant challenge for the design of S-protein-targeted inhibitors. As an example, the 2 key mutations in the S-protein receptor-binding domain (RBD), L452R, and T478K in the SARS-CoV-2 Delta variant (B.1.617.2) confer tighter binding to the host epithelial cells. Marine sulfated glycans (MSGs) demonstrate excellent inhibitory activity against SARS-CoV-2 via competitive disruption of the S-protein RBD-HSPG interactions and thus have the potential to be developed into effective prophylactic and therapeutic molecules. In this study, 7 different MSGs were evaluated for their anti-SARS-CoV-2 activity in a virus entry assay utilizing a SARS-CoV-2 pseudovirus coated with S-protein of the wild-type (Wuhan-Hu-1) or the Delta (B.1.617.2) strain. Although all tested MSGs showed strong inhibitory activity against both strains, no correlations between MSG structural features and virus inhibition could be drawn. Nevertheless, the current study provides evidence for the maintenance of inhibitory activity of MSGs against evolving SARS-CoV-2 strains.

Effective Inhibition of SARS-CoV-2 Entry by Heparin and Enoxaparin Derivatives.

Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) has caused a pandemic of historic proportions and continues to spread globally, with enormous consequences to human health. Currently there is no vaccine, effective therapeutic, or prophylactic. As with other betacoronaviruses, attachment and entry of SARS-CoV-2 are mediated by the spike glycoprotein (SGP). In addition to its well-documented interaction with its receptor, human angiotensin-converting enzyme 2 (hACE2), SGP has been found to bind to glycosaminoglycans like heparan sulfate, which is found on the surface of virtually all mammalian cells. Here, we pseudotyped SARS-CoV-2 SGP on a third-generation lentiviral (pLV) vector and tested the impact of various sulfated polysaccharides on transduction efficiency in mammalian cells. The pLV vector pseudotyped SGP efficiently and produced high titers on HEK293T cells. Various sulfated polysaccharides potently neutralized pLV-S pseudotyped virus with clear structure-based differences in antiviral activity and affinity to SGP. Concentration-response curves showed that pLV-S particles were efficiently neutralized by a range of concentrations of unfractionated heparin (UFH), enoxaparin, 6-O-desulfated UFH, and 6-O-desulfated enoxaparin with 50% inhibitory concentrations (IC50s) of 5.99 µg/liter, 1.08 mg/liter, 1.77 µg/liter, and 5.86 mg/liter, respectively. In summary, several sulfated polysaccharides show potent anti-SARS-CoV-2 activity and can be developed for prophylactic as well as therapeutic purposes.IMPORTANCE The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV-2) in Wuhan, China, in late 2019 and its subsequent spread to the rest of the world has created a pandemic situation unprecedented in modern history. While ACE2 has been identified as the viral receptor, cellular polysaccharides have also been implicated in virus entry. The SARS-CoV-2 spike glycoprotein (SGP) binds to glycosaminoglycans like heparan sulfate, which is found on the surface of virtually all mammalian cells. Here, we report structure-based differences in antiviral activity and affinity to SGP for several sulfated polysaccharides, including both well-characterized FDA-approved drugs and novel marine sulfated polysaccharides, which can be developed for prophylactic as well as therapeutic purposes.