Chitosan functionalized Mn3O4 nanoparticles counteracts ulcerative colitis in mice through modulation of cellular redox state.

Recent findings suggest a key role for reactive oxygen species (ROS) in the pathogenesis and progression of ulcerative colitis (UC). Several studies have also highlighted the efficacy of citrate functionalized Mn3O4 nanoparticles as redox medicine against a number of ROS-mediated disorders. Here we show that synthesized nanoparticles consisting of chitosan functionalized tri-manganese tetroxide (Mn3O4) can restore redox balance in a mouse model of UC induced by dextran sulfate sodium (DSS). Our in-vitro characterization of the developed nanoparticle confirms critical electronic transitions in the nanoparticle to be important for the redox buffering activity in the animal model. A careful administration of the developed nanoparticle not only reduces inflammatory markers in the animals, but also reduces the mortality rate from the induced disease. This study provides a proof of concept for the use of nanomaterial with synergistic anti-inflammatory and redox buffering capacity to prevent and treat ulcerative colitis.

Lateral flow immunoassay-based absolute point-of-care technique for authentication of meat and commercial meat products.

Point-of-care (POC) assay is an emerging technique for rapid initial screening of meat fraud incidents in a resource-limited environment. To achieve this goal, a simple extraction protocol is proposed for efficient recovery of meat proteins from raw, heat-processed, and commercial samples as well as meat offals without utilizing sophisticated laboratory settings. A sandwich-format lateral flow immunoassay (LFIA) was developed based on gold nanoparticles as labels and immunoglobulins (IgG and IgY) as biomarkers for meat species identification in raw and cooked meat mixes. The test system showed a sensitivity of 10 ng/mL allowing the detection of as low as 0.063% pork and chicken meat and 0.125% sheep meat (lamb) in meat mixes within 15 min including sample preparation. Reproducibility of the assay was confirmed by the fully consistent intra- and inter-laboratory tests and RT-PCR method. The current study developed a field-deployable extraction technique and highly-specific, sensitive, reproducible, cost-effective, and user-friendly LFIA-based assay for rapid species authentication in raw, cooked, and commercial meat samples and meat offals. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05663-2.

Integration of electroencephalogram (EEG) and motion tracking sensors for objective measure of attention-deficit hyperactivity disorder (MAHD) in pre-schoolers.

We developed an integrated device composed of a single-probe Electroencephalogram (EEG) and Charge Coupled Device (CCD) based motion sensors for objective measurement of Attention-deficit Hyperactivity Disorder (ADHD). While the measurement of attention-deficit hyperactivity disorder (MAHD) relies on the EEG signal for the assessment of attention during a given structured task, the CCD sensor depicts the movement pattern of the subjects engaged in a continuous performance task. A statistical analysis of attention and movement patterns was performed, and the accuracy of completed tasks was analyzed using indigenously developed software. The device with the embedded software is intended to improve certainty with criterion E. We used the EEG signal from a single-channel dry sensor placed on the frontal lobe of the head of the subjects (3-5 year old pre-schoolers). During the performance of the task power for delta and beta, EEG waves from the subjects are found to be correlated with relaxation and attention/cognitive load conditions. While the relaxation condition of the subject hints at hyperactivity, a more direct CCD-based motion sensor is used to track the physical movement of the subject engaged in a continuous performance task. We used our indigenously developed software for statistical analysis to derive a scale for the objective assessment of ADHD. We also compared our scale with clinical ADHD evaluations and found a significant correlation between the objective assessment of the ADHD subjects and the clinician's conventional evaluation. MAHD, the integrated device, is supposed to be an auxiliary tool to improve the accuracy of ADHD diagnosis by supporting greater criterion E certainty.

Human placental laminin: Role in neuronal differentiation, cell adhesion and proliferation.

Human placental extract has wound healing potential. Immuno-blots revealed presence of laminin in placental extract (70 +/- 0.257 µg/ml; n=3). It was purified using immuno-affinity chromatography. SDS-PAGE and SEHPLC indicated a188 kDa protein with some small peptides. Since placental laminin existed in its truncated form, its roles in cellular migration, differentiation and wound healing were verified. Induction of cellular migration and motility in rat fibroblasts were enhanced by placental laminin as observed from scratch wound assay. Promotion of neuronal differentiation of PC12 cells by placental laminin was observed by phase contrast microscopy. Confocal images showed presence of laminin on the cell surface and along the axonal processes. Significant interaction between integrin receptors and laminin responsible for cellular differentiation was demonstrated from co-localization experiments. Union between integrin receptor and its synthetic antagonist revealed retarded pattern of neurite outgrowth in laminin treated cells. Animal model studies revealed faster wound healing in the presence of placental laminin. Induction of re-epithelialization and angiogenesis in wound area by cellular proliferation and adhesion were observed. The cytokine levels showed an initial rise and gradual fall over the duration of wound healing on application of the fragmented laminin. Thus, roles of placental laminin in neuronal differentiation and wound healing were indicated.

Saraca asoca seed extract treatment recovers the trace elements imbalances in experimental murine visceral leishmaniasis.

Saraca asoca is an important plant species of India having variety of medicinal activity such as antiviral, anti-diabetic, antimicrobial, anti-inflammatory, anti-cancer etc. Indian Kala-azar (KA) or visceral leishmaniasis (VL) is a protozoan parasitic disease caused by Leishmania sp and is endemic in Indian subcontinent. VL mainly targets the poorest people who have been suffering from deficiency in protein, nutrients and essential trace elements which ultimately leads to immunodeficiency. Essential trace element, Zinc (Zn) controls multiple aspects of innate and adaptive immunity while Iron (Fe) is required for various cellular activities. Bromine (Br) is important for assembly of collagen IV scaffolds in tissue development and helps in signalling and Copper (Cu) performs several functions related to immune system. Intra-cardiac blood was collected from the experimental BALB/c mice groups including (a) healthy control, (b) infected control, (c) Saraca asoca seed extract (Sa-SE) treated groups. The trace elements level in blood of mice was measured by Energy Dispersive X-Ray Fluorescence technique. Interestingly, the decreased level of Zn, Fe and Br as well as increased level of Cu in diseased state came back to almost normal range upon treatment with Sa-SE. The trace elements imbalances thus were almost restored to normalcy by treating the experimental BALB/c mice with ethanolic seed extract of Saraca asoca.

Destabilization of ß-amyloid aggregates by thrombin derived peptide: plausible role of thrombin in neuroprotection.

ß-amyloid (Aß) aggregates involved in Alzheimer's disease (AD) are resistant to proteases but could be destabilized by small peptides designed to target specific hydrophobic regions of Aß that take part in aggregate assembly. Since thrombin and AD are intricately connected, and elastase modulates thrombin activity, elastase-digested thrombin peptides were verified for intervention in the Aß-aggregation pathway. Intact or elastase-digested thrombin destabilized Aß fibril, as demonstrated by thioflavin T assay. Peptides were synthesized employing thrombin as a template, of which, a hexapeptide (T3) showed maximum destabilization at 1 µm. ExPASy peptide cutter software coupled with mass spectrometric analysis confirmed the generation of T3 peptide from elastase-digested thrombin. TEM micrographs revealed that 30-day incubation of preformed Aß fibrils or monomers with T3 resulted in destabilization or inhibition, respectively, leading mostly to particles of 1.74 ± 0.17 nm, which roughly corresponded to Aß monomer. Surface plasmon resonance employing CM5 chip coupled with Aß40 mouse monoclonal antibody showed a drop in response when T3 was incubated with Aß fibrils between 2 and 8 h. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide and confocal microscopy demonstrated the ability of T3 to rescue neuroblastoma cells from Aß oligomer-induced cytotoxic damage. Although no [Aß-T3] adduct could be detected by mass spectrometry, an initial interaction appeared to facilitate the process of destabilization/inhibition of aggregation. T3 was comparable to standard ß-sheet breaker peptides, LPFFD and KLVFF in terms of Aß aggregate destabilization. High hydrophobicity values coupled with recognition and breaking elements make T3 a potential candidate for future therapeutic applications.

Degradation of fibrin-ß amyloid co-aggregate: A novel function attributed to ubiquitin.

Human placental extract contains numerous bioactive components that are effective wound healing, antimicrobial and anti-inflammatory agents. During our investigation on the therapeutic potency of human placental extract, we have purified ubiquitin-like molecules that showed strong fibrino(geno)lytic activity. Further investigation confirmed similar potency of ubiquitin purified from adult human erythrocyte. Additionally, ubiquitin efficiently degraded disordered amyloid ß 42 peptide (Aß42) aggregate and fibrin-Aß42 co-aggregate in vitro and reduced co-aggregate induced cytotoxicity in SH-SY5Y human neuroblastoma cells as compared to plasmin. Ubiquitin also degraded abnormal co-aggregates of fibrin with other plasma proteins such as fibronectin, albumin, lysozyme, tranthyretin and α-synuclein. To elucidate the mechanism of degradation, synthetic peptides (ADG, GKT, DQQ, QRL, LIF, AGK, HLVL) derived from ubiquitin template as well as synthetic ubiquitin (8565.32 Da) were employed. Synthetic ubiquitin completely degraded preformed Aß 42 aggregate and fibrin-Aß42 co-aggregate, whereas, the smaller synthetic peptides showed varying degrees of degradation. These observations attribute a novel function of ubiquitin that may be used for degrading abnormal fibrin clots in human body. Thorough investigation might unfold a novel molecular mechanism of ubiquitin in protein homeostasis.

Aristolochic acid and its derivatives as inhibitors of snake venom L-amino acid oxidase.

Snake venom L-amino acid oxidase (LAAO) exerts toxicity by inducing hemorrhage, pneumorrhagia, pulmonary edema, cardiac edema, liver cell necrosis etc. Being well conserved, inhibitors of the enzyme may be synthesized using the template of the substrate, substrate binding site and features of the catalytic site of the enzyme. Previous findings showed that aristolochic acid (AA), a major constituent of Aristolochia indica, inhibits Russell's viper venom LAAO enzyme activity since, AA interacts with DNA and causes genotoxicity, derivatives of this compound were synthesized by replacing the nitro group to reduce toxicity while retaining the inhibitory potency. The interactions of AA and its derivatives with LAAO were followed by inhibition kinetics and surface plasmon resonance. Similar interactions with DNA were followed by absorption spectroscopy and atomic force microscopy. LAAO-induced cytotoxicity was evaluated by generation of reactive oxygen species (ROS), cell viability assays, confocal and epifluorescence microscopy. The hydroxyl (AA-OH) and chloro (AA-Cl) derivatives acted as inhibitors of LAAO but did not interact with DNA. The derivatives significantly reduced LAAO-induced ROS generation and cytotoxicity in human embryonic kidney (HEK 293) and hepatoma (HepG2) cell lines. Confocal images indicated that AA, AA-OH and AA-Cl interfered with the binding of LAAO to the cell membrane. AA-OH and AA-Cl significantly inhibited LAAO activity and reduced LAAO-induced cytotoxicity.

Biochemical and functional analysis of corticotropin releasing factor purified from an aqueous extract of human placenta used as wound healer.

Human placental extract constitutes of innumerable therapeutically important components mostly used in wound healing arising from the skin and burn injuries. However, there is still some bioactive present in the placental extracts yet to be characterized to better under the complex process of wound healing mediated by the placental extract. In this study, the presence of corticotropin releasing factor (CRF) in an aqueous extract of human placenta was detected and quantified by dot blot and CRF-ELISA immunoassay kit respectively. Subsequently, it was purified by immuno-affinity chromatography and quantified as 0.45±0.05µg of CRF per ml of placental extract where its molecular weight found to be 4.78kDa by MALDI-TOF. To study functional analysis of CRF, an in vitro WI-38 lung fibroblast cell scratch wound model was used which indicated proliferation, motility of cells after treatment with purified CRF. Moreover, reduction in apoptosis rate of cells during closure of wound was observed from microscopy studies and FACS analysis. Also, Antalarmin, an antagonist of CRF type 1 receptor inhibited the wound closure potency of the purified component. Faster healing of wound with an elevation of IL-6 and TGF-ß during early stages of repair by placental CRF was observed on excision rat model. The process of healing was accompanied by the decrease in the level of TNF-α and IFN-γ.

Reverse Zymography: Overview and Pitfalls.

Reverse zymography is a technique by which protease inhibitor(s) in a sample could be electrophoretically separated in a substrate-impregnated acrylamide gel and their relative abundance could be semi-quantified. The gel after electrophoresis is incubated with a protease when the impregnated substrate and all other proteins of the sample are degraded into small peptides except the inhibitor(s) that show clear bands against a white background. Since reverse zymography cannot distinguish between a protease inhibitor and a protein that is resistant against proteolysis, the results should be confirmed from inhibition of protease activity by solution state assay.

Destabilization of Human Insulin Fibrils by Peptides of Fruit Bromelain Derived From Ananas comosus (Pineapple).

Deposition of insulin aggregates in human body leads to dysfunctioning of several organs. Effectiveness of fruit bromelain from pineapple in prevention of insulin aggregate was investigated. Proteolyses of bromelain was done as par human digestive system and the pool of small peptides was separated from larger peptides and proteins. Under conditions of growth of insulin aggregates from its monomers, this pool of peptides restricted the reaction upto formation of oligomers of limited size. These peptides also destabilized preformed insulin aggregates to oligomers. These processes were followed fluorimetrically using Thioflavin T and 1-ANS, size-exclusion HPLC, dynamic light scattering, atomic force microscopy, and transmission electron microscopy. Sequences of insulin (A and B chains) and bromelain were aligned using Clustal W software to predict most probable sites of interactions. Synthetic tripeptides corresponding to the hydrophobic interactive sites of bromelain showed disaggregation of insulin suggesting specificity of interactions. The peptides GG and AAA serving as negative controls showed no potency in destabilization of aggregates. Disaggregation potency of the peptides was also observed when insulin was deposited on HepG2 liver cells where no formation of toxic oligomers occurred. Amyloidogenic des-octapeptide (B23-B30 of insulin) incapable of cell signaling showed cytotoxicity similar to insulin. This toxicity could be neutralized by bromelain derived peptides. FT-IR and far-UV circular dichroism analysis indicated that disaggregated insulin had structure distinctly different from that of its hexameric (native) or monomeric states. Based on the stoichiometry of interaction and irreversibility of disaggregation, the mechanism/s of the peptides and insulin interactions has been proposed. J. Cell. Biochem. 118: 4881-4896, 2017. © 2017 Wiley Periodicals, Inc.

Cholesterol and Its Derivatives Reversibly Inhibit Proteinase K.

Microorganisms express a variety of proteases that degrade many proteins of the host body and subvert host immune response. While elucidating the mechanism/s of an immune stimulatory drug that contains bile lipid, regulation of proteolytic activity was investigated. The drug and bile lipids both stabilize Proteinase K, an aggressive protease of fungal origin against auto-digestion. Among the components of bile lipids, only cholesterol and its derivatives stabilize the enzyme. Biophysical evidences such as scattering of light, intrinsic and extrinsic fluorescence emission spectra, circular dichroism spectra, atomic force microscopy, and transmission electron microscopy images indicated that cholesterol and its derivatives interact with Proteinase K. Inhibition kinetics using esterolysis of ATEE revealed non-competitive inhibition by cholesterol. Surface Plasmon Resonance and mass spectrometric analysis indicated 1:1 stoichiometry of binding and with dissociation constant in the µM range. Further, the presence of four cholesterol recognition amino acid consensus motifs (CRAC motifs I-IV) was identified in Proteinase K. Bioinformatics analysis revealed that the whole stretch of cholesterol interacts very well with the hydrophobic groove of motif II only among the four CRAC motifs. Variation of cholesterol content of HepG2 human liver carcinoma cells showed positive correlation with binding of fluorescence tagged Proteinase K. Under these conditions, binding of Proteinase K to the cells did not affect their morphology, viability and growth kinetics. Cell bound Proteinase K could be released by an excess of its substrate, thereby restoring reversibly its proteolytic activity. J. Cell. Physiol. 232: 596-609, 2017. © 2016 Wiley Periodicals, Inc.

Identification of the anti-oxidant components in a two-step solvent extract of bovine bile lipid: Application of reverse phase HPLC, mass spectrometry and fluorimetric assays.

An ether extract of nine different bacterial metabolites in combination with two solvent extract (ether followed by ethanol) of bile lipids from ox gall bladder is used as an immune stimulator drug. Over the years bile acids are discussed regarding their anti-oxidant and lipid peroxidation properties. Since some of the bile acids are known to be potent antioxidants, presence of similar activity in the solvent extract of ox bile lipid was investigated using TLC and reverse phase HPLC systems. Fractions from HPLC were analyzed with mass spectrometry using electrospray ionization. The presence of twelve different bile acids along with other substances in small proportions including fatty acids, sulfate conjugates and bile pigments were confirmed. The twelve separated peaks had similar retention times as those of tauroursodeoxycholic acid, glycoursodeoxycholic acid, taurocholic acid, glycocholic acid, glycochenodeoxycholic acid, taurochenodeoxycholic acid, taurodeoxycholic acid, cholic acid, ursodeoxycholic acid, chenodeoxycholic acid, deoxycholic acid, and lithocholic acid. Subsequently, all fractions were tested for their anti-oxidative property on HepG2 cells exposed to H2O2 that served as an oxidative injury model. Four fluorescent dyes H2DCF DA, MitoSOX red, Amplex red and DAF-2 DA were used for estimation of reactive radicals in the HepG2 cells. Among the separated bile acids, tauroursodeoxycholic acid, glycoursodeoxycholic acid and ursodeoxycholic acid prevented the HepG2 cells from H2O2-induced oxidative stress.

An Enzyme from Aristolochia indica Destabilizes Fibrin-ß Amyloid Co-Aggregate: Implication in Cerebrovascular Diseases.

Fibrinogen and ß-amyloid (Aß) peptide independently form ordered aggregates but in combination, they form disordered structures which are resistant to fibrinolytic enzymes like plasmin and cause severity in cerebral amyloid angiopathy (CAA). A novel enzyme of 31.3 kDa has been isolated from the root of the medicinal plant Aristolochia indica that showed fibrinolytic as well as fibrin-Aß co-aggregate destabilizing properties. This enzyme is functionally distinct from plasmin. Thrombolytic action of the enzyme was demonstrated in rat model. The potency of the plant enzyme in degrading fibrin and fibrin-plasma protein (Aß, human serum albumin, lysozyme, transthyretin and fibronectin) co-aggregates was demonstrated by atomic force microscopy, scanning electron microscopy and confocal microscopy that showed better potency of the plant enzyme as compared to plasmin. Moreover, the plant enzyme inhibited localization of the co-aggregate inside SH-SY5Y human neuroblastoma cells and also co-aggregate induced cytotoxicity. Plasmin was inefficient in this respect. In the background of limited options for fragmentation of these co-aggregates, the plant enzyme may appear as a potential proteolytic enzyme.

Immunoglobulin isotype isolated from human placental extract does not interfere in complement-mediated bacterial opsonization within the wound milieu.

The wound healing potency of an aqueous extract of placenta can be evaluated through the presence of numerous regulatory components. The presence of glycans was detected by thin layer chromatography and fluorophore-assisted carbohydrate electrophoresis. Mass spectrometric analysis revealed the existence of multiple fragments of immunoglobulin G (IgG). IgG was present in the extract at a concentration of 25.2 ± 3.97 µg/ml. IgG possesses anti-complementary activity by diverting the complement activation from target surface. Thus, effect of placental IgG on complement-bacteria interaction was investigated through classical and alternative pathway and the preparation was ascertained to be safe with respect to their interference in the process of bacterial opsonization.

Evaluation of the presence of reduced nicotinamide adenine dinucleotide phosphate in bacterial metabolites used as immunostimulators and its role in nitric oxide induction.

Bacterial metabolites that act as immunostimulators have aroused interest because of their therapeutic potential in several immune disorders. These metabolites are complex, heterogeneous, and comprise numerous immune-boosting biomolecules. To better understand their immune stimulatory properties, characterization of their components is essential. An ether extract of metabolites from nine bacterial species was analyzed for the presence of reduced nicotinamide adenine dinucleotide phosphate (NADPH) or other fluorophores. This metabolite in combination with bile lipids is a licensed immune stimulatory drug. Excitation of the extract at 340 nm resulted in fluorescence with an emission maximum of around 410 nm, which is fairly specific for NADH and NADPH. Reverse-phase-HPLC and electro-spray ionization-mass analysis confirmed the presence of NADPH in the bacterial metabolites. Quantification by glutathione reductase assay indicated 11.90 ± 0.01 µM of NADPH in the metabolites. Further characterization of the individual bacterial extracts of the metabolite confirmed the presence of NADPH. Subsequently, studies were performed to evaluate the role/s of NADPH in immune-stimulatory drugs. NADPH is known to be involved in production of nitric oxide (NO), which has versatile roles in the immune system. The biological function of NADPH in NO induction by RAW 264.7 (mouse macrophage) cells was evaluated and it was found that bacterial NADPH has a significant role in inducing NO and that NADPH from individual bacterial extracts is capable of inducing NO. Investigation on the stability and biological potency of NADPH in bacterial metabolites is important because of NADPH's wide therapeutic applications, most of which are associated with its role in NO induction.

PI3K-mediated proliferation of fibroblasts by Calendula officinalis tincture: implication in wound healing.

Calendula officinalis, a member of the Asteraceae family, is a flowering plant and has been used for its antibacterial, antifungal, antiviral, antiinflammatory, anticancer and wound healing activity. The mode of action of C. officinalis tincture on wound healing is poorly understood. Here, we investigated the role of C. officinalis tincture (CDOT) on cell viability and wound closure. C. officinalis tincture stimulated both proliferation and migration of fibroblasts in a statistically significant manner in a PI3K-dependent pathway. The increase in phosphorylation of FAK (Tyr 397) and Akt (Ser 473) was detected after treatment of CDOT. Inhibition of the PI3K pathway by wortmannin and LY294002 decreased both cell proliferation and cell migration. HPLC-ESI MS revealed the presence of flavonol glycosides as the major compounds of CDOT. Altogether, our results showed that CDOT potentiated wound healing by stimulating proliferation and migration of fibroblast in a PI3K-dependent pathway, and the identified compounds are likely to be responsible for wound healing activity.

Collagenases in an ether extract of bacterial metabolites used as an immunostimulator induces TNF-α and IFN-γ.

Non-specific immunostimulation by bacterial extracts and their components are widely accepted for the prevention and treatment of several infectious diseases. An ether extract of the metabolites of ß-streptococcus, Staphylcoccus albus, Staphylcoccus aureus, Escherichia coli, Haemophilus influenza, Moraxella caterhalis, Salmonella typhi (standard O & H), Salmonella paratyphi (A & B) and Diptheroid bacilli along with bile lipids is used as a licensed drug for immunostimulation. While characterizing the drug, we observed gelatinolytic/collagenolytic activity in the ether extract by zymography. This activity was contributed by each bacterial species as observed by collagen zymography of individual extract. Immuno-blot also confirmed the presence of collagenases in the pooled extract whose activity was estimated to be 0.081 U/ml ± 0.005 by DQ-gelatin assay. The enzyme was purified by immuno-affinity chromatography. Homogeneity of the preparation was demonstrated by SDS-PAGE and SE-HPLC. Degradation of collagen by purified collagenases was visualized by atomic force microscopy and transmission electron microscopy wherein, fragmentation of collagen leading to loss of network structure occurred under physiological conditions. Results indicated that purified collagenases can trigger the release of pro-inflammatory cytokines TNF-α and IFN-γ in-vitro and in-vivo without inducing detectable stress and toxicity on both models. The findings suggest that bacterial collagenases remain stable and biological functional in an organic solvent validating its potential for industrial and medical applications as the enzymes are key regulators of inflammatory and immune responses.

Phosphodiesterase from Daboia russelli russelli venom: purification, partial characterization and inhibition of platelet aggregation.

Phosphodiesterases (PDEs) belong to a super-family of enzymes that have multiple roles in the metabolism of extracellular nucleotides and regulation of nucleotide-based intercellular signalling. A PDE from Russell's viper (Daboia russelli russelli) venom (DR-PDE) was purified by gel filtration, ion exchange and affinity chromatographies. Homogeneity of the preparation was verified by SDS-PAGE, SE-HPLC and mass spectrometry. It was free from 5'-nucleotidase, alkaline phosphatase and protease activities. Identity of the enzyme was ensured from partial sequence homology with other PDEs. DR-PDE was inactivated by polyvalent anti-venom serum and metal chelators. The enzyme was partially inhibited by the root extracts of four medicinal plants but remained unaffected by inhibitors of intracellular PDEs. DR-PDE hydrolyses ADP and thus, strongly inhibits ADP-induced platelet aggregation in human platelet rich plasma. This study leads to better understanding of a component of Russell's viper venom that affects homoeostatic system of the victim.

Human placental extract mediated inhibition of proteinase K: implications of heparin and glycoproteins in wound physiology.

Efficient debridement of the wound bed following the removal of microbial load prevents its progression into a chronic wound. Bacterial infection and excessive proteolysis characterize impaired healing and therefore, their inhibition might restore the disturbed equilibrium in the healing process. Human placental extract exhibits reversible, non-competitive inhibition towards Proteinase K, a microbial protease, by stabilizing it against auto-digestion. Scattering and fluorescence studies followed by biochemical analysis indicated the involvement of a glycan moiety. Surface plasmon resonance demonstrated specific interaction of heparin with Proteinase K having Kd in µM range. Further, Proteinase K contains sequence motifs similar to other heparin-binding proteins. Molecular docking revealed presence of clefts suitable for binding of heparin-derived oligosaccharides. Comprehensive analysis of this inhibitory property of placental extract partly explains its efficacy in curing wounds with common bacterial infections.