Wound-healing activity of glycoproteins from white jade snail (Achatina fulica) on experimentally burned mice.

Burns are a global public health problem and the treatment of burn wounds is a major medical and economic issue. White jade snails (Achatina fulica) are now widely distributed in Asia, and they have been used to treat burns in folk medicine of China. In this study, the glycoproteins from white jade snails were investigated and their effect on burn healing was evaluated by a mouse burn model. The results showed that the snail mucus was mainly composed of proteins and polysaccharides, and it had good adhesion. The main component of snail mucus was glycoprotein from the results of DEAE Sepharose FF ion exchange chromatography. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging effect of 1 mg/mL snail mucus reached 13.77%. The wound healing rate of the snail mucus group was higher than that of the control group (p < 0.0001). Histopathological results showed that mice in the snail mucus group had a faster healing than that of the control group. The biochemical analysis was in agreement with the histopathological findings. These results suggested that glycoproteins from snail mucus showed effective wound healing activities in the skin of experimentally burned mice.

Extraction, purification, characterization, and rheological properties of a glycoprotein from Cynomorium songaricum Rupr.

Cynomorium songaricum Rupr is widely known in China as a traditional herbal medicine. In this study, single-factor experiments and response surface methodology were used to optimize the extraction of Cynomorium songaricum Rupr glycoprotein (CSG). The results show that a maximum glycoprotein yield of 6.39 ± 0.32% was achieved at a ratio of solid to liquid 32:1 for 4.2 H at 52 °C. Then, the IR, monosaccharide composition, amino acid composition, type of glycopeptide linkage, and average molecular weight of CSG-1 purified from CSG were characterized. The results indicate that CSG-1 presented the characteristic absorption peak of polysaccharide and protein, including four monosaccharides and 17 amino acids, had O-linked glycopeptide bonds, Mw , Wn , Mw /Mn , Mp , and the z-average were 5.343 × 106 , 3.203 × 106 , 1.668, 8.911 × 106 , and 6.948 × 106 , respectively. Besides, CSG-1 solution was described by the Herschel-Bulkley model and it behaved as a shear-thinning fluid. Also, under a frequency sweep the moduli G' and G″ both increased with increasing CSG-1 concentration and the CSG-1 dispersions had weak thermal stability over the temperature sweep. These results provide a scientific basis for the further study of Cynomorium songaricum Rupr.

A Protocol for Studying HIV-1 Envelope Glycoprotein Function.

HIV-1 envelope glycoproteins (Envs) bind to CD4 receptor and CCR5/CXCR4 coreceptor and mediate viral entry (Feng et al., 1996; Herschhorn et al., 2016, 2017; Kwong et al., 1998). HIV-1 Envs are the sole target of neutralizing antibodies and a main focus of vaccine development (Flemming et al., 2018). Here, we provide a step-by-step protocol to measure Env sensitivity to ligands, cold, and small molecules, as well as to study viral infectivity and to dissect parameters affecting HIV-1 Env function. For complete details on the use and execution of this protocol, please refer to Harris et al. (2020).

Purification and characterization of non-enzymatic glycoprotein (NEGp) from flax seed buffer extract that exhibits anticoagulant and antiplatelet activity.

The current study deals with the purification and characterization of non-enzymatic glycoprotein (NEGp) from flax seed buffer extract. Sephadex G-100 and DEAE-A25 column chromatography techniques were employed to isolate NEGp. NEGp showed single sharp band at 29 kDa region on 10% SDS-PAGE, and under reduced and non-reduced conditions revealed its monomeric nature. Besides, NEGp taken up the PAS stain at 29 kDa region reveals the presence of carbohydrate moiety. Purity of NEGp was adjudged by RP-HPLC, as it revealed a single sharp peak at the retention time of 3.4 min. The exact molecular mass of NEGp was found to be 26 kDa which was confirmed by MALDI-TOF. Circular di-chromism spectra of NEGp showed 12.0% α-helix, 24.3% α-helix turn and 63.7% random coils without beta pleated sheets. NEGp was found to exhibit anticoagulant activity by extending clotting time of both platelet rich plasma and platelet poor plasma from control 240 s to 1800 s and 280 s to 2100 s respectively at the concentration of 8 µg. NEGp inhibited the agonists such as ADP, epinephrine and arachidonic acid induced platelet aggregation in washed platelets. The percentage of inhibition was found to be 70%, 80% and 60% respectively. While, it did not interfere in thrombin, PAF and collagen induced platelet aggregation. NEGp did not hydrolyse RBC membrane, devoid of haemorrhagic and edema inducing properties in experimental mice.

Orally hypoglycemic activity of an insulin mimetic glycoprotein isolated from Cnidoscolus quercifolius Pohl. (Euphorbiaceae) seeds, Cq-IMP.

The genus Cnidoscolus (Euphorbiaceae) is widely distributed in tropical areas. In the Northeast of Brazil, the species C. quercifolius is endemic and has been used in traditional medicine. In this study, a novel protein was isolated from C. quercifolius seeds and characterized by its molecular weight, primary structure, isoelectric point (pI), and carbohydrate content. The hypoglycemic activity of this protein was investigated by in vitro assay with the RIN-5F glucose-responsive cell line and in vivo test using alloxan-induced diabetic mice models. In addition, safe use of the protein was also investigated by cytotoxicity, hemagglutinating, and immunogenicity assays. The protein which was named Cq-IMP (Cnidoscolus quercifolius - Insulin Mimetic Protein) showed a single 11.18 KDa glycopolypeptide chain (16.4% of carbohydrates, m/m), pI of 8.0 and N-terminal sequence (TKDPELKQcKKQQKKqQQYDDDDKK) with similarity around 46-62% to sucrose binding protein-like and vicilin-like protein that was confirmed by mass spectrometry tryptic peptides analysis. Besides that, Cq-IMP presented anti-insulin antibody cross-reactivity as hypoglycemic activity in both in vitro and in vivo models. Additionally, it did not present any toxicity by methods tested. In conclusion, Cq-IMP is an insulin-mimetic protein, with a potent hypoglycemic activity and no toxicity showing great potential for therapeutic applications and drug development.

Purification, characterization, and functional properties of a novel glycoprotein from tartary buckwheat (Fagopyrum tartaricum) seed.

A pure glycoprotein (BGP4-I) was obtained from tartary buckwheat seeds by aqueous extraction followed by DEAE-Sepharose Fast Flow ion exchange chromatography and Sephadex G-100 gel filtration chromatography. The average molecular weight of BGP4-I, as determined by high performance gel permeation chromatography, was 123.43 kDa. The structure of BGP4-I was characterized based on Fourier transform infrared spectroscopy, circular dichroism spectroscopy, and nuclear magnetic resonance spectroscopy, etc. Based on the nano-liquid chromatography-coupled electrospray ionization mass spectrometry analysis of the amino acid sequence of BGP4-I, belongs unequivocally to the glycosyl hydrolase family 1 in the Carbohydrate Active Enzymes database by alignment studies. The specific activity of BGP4-I was 18.44 µmol/min/mg on the substrate p-nitrophenyl-ß-d-glucopyranoside. Furthermore, BGP4-I is unique in its specificity for some substrates. These results suggest that the BGP4-I from tartary buckwheat seeds is a novel specific ß-glucosidase setting the foundation for potential applications in the food industry.

L-cysteine functionalized straticulate C3N4 for the selective enrichment of glycopeptides.

The facile enrichment of glycopeptides or glycoproteins poses great challenges for glycoproteomic research. In this study, a novel hydrophilic material, named zwitterionic hydrophilic L-cysteine derivatized straticulate-C3N4 composites (LCAC), were synthesized and evaluated for the enrichment of N-glycopeptides. LCAC exhibited good biocompatibility, excellent hydrophilicity and selectivity, by virtue of the large surface of C3N4 and the zwitterionic property offered by cysteine. LCAC demonstrated excellent performance for N-glycopeptide enrichment with the sensitivity of 0.033 fmol/µL, selectivity of 1:100, and high recovery rate (∼85%). The performance of LCAC was demonstrated by the identification of 35 N-glycopeptides from IgG, as well as capturing 1809 human urine N-glycopeptides corresponding to 876 N-glycoproteins. Comparing the LCAC with our developed phenylboronic acid functionalized material showed a certain complementary due to the different binding mechanism. The simple production and enhanced hydrophilic properties make the material a promising choice for glycoproteomics researches.

Recovery of milk fat globule membrane (MFGM) from buttermilk: effect of Ca-binding salts.

In this Research Communication we present a study of the effect of Ca-binding salts on the recovery of milk fat globule membrane (MFGM) from buttermilk. Sodium phosphate buffer was used for the purpose of MFGM recovery from buttermilk for the first time and we showed that 0.1 M buffer at pH 7.2 was the most effective for the recovery of MFGM. The fact of high efficacy of sodium phosphate buffer in recovery of MFGM from buttermilk allowed us to suggest that MFGM in buttermilk is present in association with casein through Ca- bridges formed between phospholipids of MFGM and phosphate groups of casein, primarily with k-casein as the peripheral protein of casein micelles.

Biomedical Applications of Lectins from Traditional Chinese Medicine.

Lectins are proteins or glycoproteins of non-immune origin which have at least one noncatalytic domain that bind reversibly to specific mono or oligosaccharides. Traditional Chinese Medicine (TCM) involves a broad range of medicinal practices sharing common concepts which have been developed in China and are based on a tradition of more than thousands of years. Plant materials which are commonly used in TCM as a complementary or alternative for Western medical treatments contain a considerable number of important lectins. These lectins have been reported to have various applications and uses such as cancer treatment, glycoconjugate research, biomarker development, and others. Here, we summarize the available literature related to lectins from TCM and recent trends in their potential biomedical applications.

Glycoproteomic Alterations in Drug-Resistant Nonsmall Cell Lung Cancer Cells Revealed by Lectin Magnetic Nanoprobe-Based Mass Spectrometry.

Understanding the functional role of glycosylation-mediated pathogenesis requires deep characterization of glycoproteome, which remains extremely challenging due to the inherently complex nature of glycoproteins. We demonstrate the utility of lectin-magnetic nanoprobe (MNP@lectin) coupled to Orbitrap HCD-CID-MS/MS for complementary glycotope-specific enrichment and site-specific glycosylation analysis of the glycoproteome. By three nanoprobes, MNP@ConA, MNP@AAL, and MNP@SNA, our results revealed the first large-scale glycoproteome of nonsmall cell lung cancer (NSCLC) with 2290 and 2767 nonredundant glycopeptides confidently identified (Byonic score ≥100) in EGFR-TKI-sensitive PC9 and -resistant PC9-IR cells, respectively, especially with more fucosylated and sialylated glycopeptides in PC9-IR cells. The complementary enrichment was demonstrated with only five glycopeptides commonly enriched in three MNP@lectins. Glycotope specificity of 79 and 62% for enrichment was achieved using MNP@AAL and MNP@SNA, respectively. Label-free quantitation revealed predominant fucosylation in PC9-IR cells, suggesting its potential role associated with NSCLC resistance. Moreover, without immunoprecipitation, this multilectin nanoprobe allows the sensitive identification of 51 glycopeptides from 10 of 12 reported sites from onco-protein EGFR. Our results not only demonstrated a sensitive approach to study the vastly under-represented N-glycoprotome but also may pave the way for a glycoproteomic atlas to further explore the site-specific function of glycoproteins associated with drug resistance in NSCLC.

Nematicidal activity of 'major royal jelly protein'-containing glycoproteins from Acacia honey.

Parasitic nematodes infect more than two billion people worldwide particularly in developing countries. We previously reported nematicidal activity of natural honey using model nematode Caenorhabditis elegans. In this study, characterization of nematicidal effects of natural honey and its glycoproteins has been carried out. Chromatographically separated honey glycoproteins showed potent anti-C. elegans activity (LD50 = 100 ng proteins/µL). Honey glycoproteins with molecular masses of ∼260 kD and ∼160 kD comprised of 'major royal jelly protein-1'-containing complexes. In these complexes, MRJP1 was present in different glycosylation forms. Quantitative PCR based gene expression assays described molecular functions of C. elegans affected by honey and honey glycoproteins. Expression of 14 gene transcripts associated with key cellular and molecular functions including energy metabolism, cytoskeleton, cell division, transcription and translation was analyzed. Acacia honey exerted a concentration-dependent alteration of gene transcripts involved in the citric acid cycle (mdh-1 and idhg-1) and cytoskeleton (act-1, act-2, and arp6). Likewise, MRJP1-containing glycoproteins caused down-regulation of arp-6 and idhg-1; and up-regulation of act-1 and mdh-1 gene transcripts. Consistent down-regulation of isocitrate dehydrogenase encoding idhg-1 gene which is among the rate-controlling enzymes of the citric acid cycle was considered as main biochemical factor involved in the nematicidal activity of honey and MRJP-containing glycoproteins. Acacia honey suppressed the expression of gene transcripts encoding actin-2, while honey glycoproteins did not. Hence, honey partly exerted anti-C. elegans activity by decreasing the transcription of actin-2 gene transcripts, demonstrated by a defect in the movement and egg laying. Moreover, arp-6 gene transcripts encoding actin-related protein 6 was significantly and constantly down-regulated by honey and honey proteins.

[Purification and cytotoxicity of glycoprotein isolated from Dendrobium huoshanense].

Dendrobium huoshanense is a rare traditional Chinese medicinal herb, and the anti-tumor activity of its polysaccharides is a research hotspot in traditional Chinese medicine resources domain. This study aims to explore the material basis for the anti-tumor activity of polysaccharide. D. huoshanense was used as raw material in the experiment, and the different protein components were obtained through low salt solution extraction and ammonium sulfate fractional precipitation. Then glycoprotein components were determined by SDS-PAGE electrophoresis staining, and were further isolated and purified by DEAE ion column and Sephadex gel column. At the same time, MTT assay was used in detecting the cytotoxicity of different products on HepG2 cells in vitro. As a result, three kinds of glycoprotein components RG1, RG2, RG3 with relative molecular mass of 22.5, 19.8, 15.6 kDa were gained, and the IC50 of three compounds on human liver cancer cell HepG2 was 534.23 mg•L⁻¹, meanwhile IC50 of single glycoprotein component RG1, RG2 was 432.96, 413.91 mg•L⁻¹ respectively, and glycoprotein component RG3 had no cytotoxicity on HepG2 cells. All in all, the experiment results suggested that two kinds of glycoproteins components with relative molecular mass of 22.5, 19.8 kDa may be one of the material basis for anti-tumor activity of D. huoshanense polysaccharide, and they had a synergistic effect.

Structural and functional characterization of a novel immunomodulatory glycoprotein isolated from ajowan (Trachyspermum ammi L.).

Ajowan (Trachyspermum ammi L.) spice has been used in food preparations and also as a traditional medicine in Ayurveda. Although a number of pharmacological activities have been attributed to ajowan, its role in immunomodulation is not known. The main objective of the present study is to examine the macromolecular immunomodulatory components. Macrophage activation was studied by nitric oxide (NO) release, phagocytosis and secretion of pro-inflammatory cytokines as the markers. Ethanol precipitate (fractional) of ajowan aqueous extract was subjected to conventional chromatography (Q Sepharose followed by Bio-Gel P-100). One of the proteins (30.7 kDa; ajowan glycoprotein or Agp) showed effective mitogenic activity towards splenocytes. Agp is a O-linked glycoprotein with the glycans contributing to one-third of the molecular mass. It has a high content of glutamic acid, serine, aspartic acid and proline whereas galactose (45.7%), arabinose (34.5%), glucose (7%), mannose (5%) and xylose (4%) are the constituent sugars. Secondary structure analysis indicated that Agp contains 79% α-helices and 21% random coil. Internal sequencing of the tryptic peptides did not show homology with the existing proteins in the database (BLAST). Agp at 1 µg/mL induced proliferation of B-cell enriched murine splenocytes and activated macrophages in releasing NO and promoted phagocytosis (p < 0.01). RAW 264.7 cells produced pro-inflammatory cytokines (IL-12, TNF-α and IFN-γ) at 1 µg/mL Agp (p < 0.01). Deproteinized Agp (dpAgp) failed to elicit activation of murine immune cells, whereas deglycosylated Agp (20 kDa; dgAgp) showed compromised efficiency. This is the first report of an immunomodulatory protein from ajowan.

Purification and immunochemical characterization of Pla l 2, the profilin from Plantago lanceolata.

Profilins are small actin-binding proteins found in eukaryotes and involved in cell development, cytokinesis, membrane trafficking, and cell motility. From an allergenic point of view, profilins are panallergens usually involved in allergic polysensitization, although they are generally recognized as minor allergens. The objectives of this study were to identify and characterize the profilin from Plantago lanceolata pollen and to investigate the cross-reactivity between profilins from different pollen allergenic sources. Profilins from P. lancelolata (Pla l 2) and palm tree pollen (Pho d 2) were purified by affinity chromatography, deeply characterized and identified by mass spectrometry. Pla l 2 allergenicity was confirmed by immunoblot with serum samples from a patient population sensitized to profilin. Immunoblot inhibition was performed to study IgG reactivity between different pollen profilins. IgE cross-reactivity was demonstrated by ImmunoCAP inhibition. Pla l 2 is the second P. lanceolata allergen included in the IUIS Allergen Nomenclature database. Four peptides from purified Pla l 2 were identified with percentages of homology with other pollen profilins between 73 and 86%. Eighty-six percent (21/24) of the patient population recognized Pla l 2. The allergenic relatedness between Pla l 2, Pho d 2 and six pollen profilins was confirmed, and IgE cross-reactivity of Pla l 2 with rBet v 2 and rPhl p 12 was demonstrated. Pla l 2 is the profilin from P. lanceolata. The demonstrated allergenicity of this protein and its cross-reactivity with other pollen profilins support its use in profilin diagnostic assays.

Quantitative Secretome Analysis of Activated Jurkat Cells Using Click Chemistry-Based Enrichment of Secreted Glycoproteins.

Quantitative secretome analyses are a high-performance tool for the discovery of physiological and pathophysiological changes in cellular processes. However, serum supplements in cell culture media limit secretome analyses, but serum depletion often leads to cell starvation and consequently biased results. To overcome these limiting factors, we investigated a model of T cell activation (Jurkat cells) and performed an approach for the selective enrichment of secreted proteins from conditioned medium utilizing metabolic marking of newly synthesized glycoproteins. Marked glycoproteins were labeled via bioorthogonal click chemistry and isolated by affinity purification. We assessed two labeling compounds conjugated with either biotin or desthiobiotin and the respective secretome fractions. 356 proteins were quantified using the biotin probe and 463 using desthiobiotin. 59 proteins were found differentially abundant (adjusted p-value ≤0.05, absolute fold change ≥1.5) between inactive and activated T cells using the biotin method and 86 using the desthiobiotin approach, with 31 mutual proteins cross-verified by independent experiments. Moreover, we analyzed the cellular proteome of the same model to demonstrate the benefit of secretome analyses and provide comprehensive data sets of both. 336 proteins (61.3%) were quantified exclusively in the secretome. Data are available via ProteomeXchange with identifier PXD004280.

Advances in high frequency ultrasound separation of particulates from biomass.

In recent years the use of high frequency ultrasound standing waves (megasonics) for droplet or cell separation from biomass has emerged beyond the microfluidics scale into the litre to industrial scale applications. The principle for this separation technology relies on the differential positioning of individual droplets or particles across an ultrasonic standing wave field within the reactor and subsequent biomass material predisposition for separation via rapid droplet agglomeration or coalescence into larger entities. Large scale transducers have been characterised with sonochemiluminescence and hydrophones to enable better reactor designs. High frequency enhanced separation technology has been demonstrated at industrial scale for oil recovery in the palm oil industry and at litre scale to assist olive oil, coconut oil and milk fat separation. Other applications include algal cell dewatering and milk fat globule fractionation. Frequency selection depends on the material properties and structure in the biomass mixture. Higher frequencies (1 and 2MHz) have proven preferable for better separation of materials with smaller sized droplets such as milk fat globules. For palm oil and olive oil, separation has been demonstrated within the 400-600kHz region, which has high radical production, without detectable impact on product quality.

A Lectin Purified from Blood Red Bracket Mushroom, Pycnoporus sanguineus (Agaricomycetidae), Mycelium Displayed Affinity Toward Bovine Transferrin.

Fungal lectins constitute excellent ligands for development of affinity adsorbents useful in affinity chromatography. In this work, a lectin was purified from Pycnoporus sanguineus (PSL) mycelium using 3 procedures: by affinity chromatography, using magnetic galactosyl-nanoparticles or galactose coupled to Sepharose, and by ionic exchange chromatography (IEC). The highest lectin yield was achieved by IEC (55%); SDS-PAGE of PSL showed 2 bands with molecular mass of 68.7 and 55.2 kDa and IEC displayed 2 bands at pi 5.5 and 5.2. The lectin agglutinates rat erythrocytes, exhibiting broad specificity toward several monosaccharides, including galactose. The agglutination was also inhibited by the glycoproteins fetal calf fetuin, bovine lactoferrin, bovine transferrin, and horseradish peroxidase. The lectin was then used to synthesize an affinity adsorbent (PSL-Sepharose) and the interaction with glycoproteins was evaluated by analyzing their chromatographic behaviors. The strongest interaction with the PSL-derivative was observed with transferrin, although lower interactions were also displayed toward fetuin and lactoferrin. These results indicate that the purified PSL constitutes an interesting ligand for the design of affinity adsorbents to be used (i.e., in glycoprotein purification).

Activity of Extracts from Submerged Cultured Mycelium of Winter Mushroom, Flammulina velutipes (Agaricomycetes), on the Immune System In Vitro.

Extracts from submerged cultured mycelium of two strains of Flammulina velutipes, a popular culinary mushroom, were obtained by ultrasound and tested in vitro to determine their activity in innate immunity (monocytes/ macrophages). In addition, polyclonal antibodies against the extracts were produced. Both extracts have similar glycoproteins that contain mannose and glucose but have different glycoproteins with galactoseamine units. Two novel immunogenic glycoproteins with molecular weights of 32 and 25 kDa have been revealed. It is thought that these proteins are produced only by submerged cultured mycelium. Both extracts show immune-enhancing activity based on the significant modification of various parameters such as cytokine production, phagocytosis, and reactive oxygen species production.

Immunomodulatory Effects of Nontoxic Glycoprotein Fraction Isolated from Rice Bran.

Rice bran, a by-product of brown rice milling, is a rich source of dietary fiber and protein, and its usage as a functional food is expected to increase. In this study, immunomodulatory effects of glycoprotein obtained from rice bran were studied in normal mice and mouse models of cyclophosphamide-induced immunosuppression. We prepared glycoprotein from rice bran by using ammonium precipitation and anion chromatography techniques. Different doses of glycoprotein from rice bran (10, 25, and 50 mg/kg) were administered orally for 28 days. On day 21, cyclophosphamide at a dose of 100 mg/kg was administered intraperitoneally. Glycoprotein from rice bran showed a significant dose-dependent restoration of the spleen index and white blood cell count in the immunocompromised mice. Glycoprotein from rice bran affected the immunomodulatory function by inducing the proliferation of splenic lymphocytes, which produce potential T and B cells. Moreover, it prevented cyclophosphamide-induced damage of Th1-type immunomodulatory function through enhanced secretion of Th1-type cytokines (interferon-γ and interleukin-12). These results indicate that glycoprotein from rice bran significantly recovered cyclophosphamide-induced immunosuppression. Based on these data, it was concluded that glycoprotein from rice bran is a potent immunomodulator and can be developed to recover the immunity of immunocompromised individuals.

Microbial glycolipoprotein-capped silver nanoparticles as emerging antibacterial agents against cholera.

BACKGROUND: With the increased number of cholera outbreaks and emergence of multidrug resistance in Vibrio cholerae strains it has become necessary for the scientific community to devise and develop novel therapeutic approaches against cholera. Recent studies have indicated plausibility of therapeutic application of metal nano-materials. Among these, silver nanoparticles (AgNPs) have emerged as a potential antimicrobial agent to combat infectious diseases. At present nanoparticles are mostly produced using physical or chemical techniques which are toxic and hazardous. Thus exploitation of microbial systems could be a green eco-friendly approach for the synthesis of nanoparticles having similar or even better antimicrobial activity and biocompatibility. Hence, it would be worth to explore the possibility of utilization of microbial silver nanoparticles and their conjugates as potential novel therapeutic agent against infectious diseases like cholera. RESULTS: The present study attempted utilization of Ochrobactrum rhizosphaerae for the production of AgNPs and focused on investigating their role as antimicrobial agents against cholera. Later the exopolymer, purified from the culture supernatant, was used for the synthesis of spherical shaped AgNPs of around 10 nm size. Further the exopolymer was characterized as glycolipoprotein (GLP). Antibacterial activity of the novel GLP-AgNPs conjugate was evaluated by minimum inhibitory concentration, XTT reduction assay, scanning electron microscopy (SEM) and growth curve analysis. SEM studies revealed that AgNPs treatment resulted in intracellular contents leakage and cell lysis. CONCLUSION: The potential of microbially synthesized nanoparticles, as novel therapeutic agents, is still relatively less explored. In fact, the present study first time demonstrated that a glycolipoprotein secreted by the O. rhizosphaerae strain can be exploited for production of AgNPs which can further be employed to treat infectious diseases. Although this type of polymer has been obtained earlier from marine fungi and bacteria, none of these reports have studied the role of this polymer in AgNPs synthesis and its application in cholera therapy. Interestingly, the microbial GLP-capped AgNPs exhibited antibacterial activity against V. cholerae comparable to ciprofloxacin. Thus the present study may open up new avenues for development of novel therapeutic agents for treatment of infectious diseases. Graphical abstract Development of novel therapeutic agents for treatment of cholera.