Purification of a potent mitogenic homodimeric Penicillium griseoroseum lectin and its characterisation.

Penicillium griseoroseum lectin was 80-fold purified by successive DEAE Sepharose anion exchange and Sephadex G-100 gel permeation chromatography. P. griseoroseum lectin exhibited haemagglutination activity towards protease-treated rabbit erythrocytes. It showed specificity towards various carbohydrates such as d-mannose, N-acetyl-d-glucosamine, mucins, and so forth. P. griseoroseum lectin was found as a glycoprotein with glycan content of 4.33%. Purified P. griseoroseum lectin is homodimeric having a molecular mass of 57 kDa with subunit molecular mass of 28.6 kDa. Haemagglutination activity of purified P. griseoroseum lectin was completely stable from 25°C to 35°C at a pH range of 6-7.5. Lectin activity was not influenced by divalent metal ions and denaturants. P. griseoroseum lectin manifested mitogenicity towards mice splenocytes and activity reached a peak at 75 µg/ml of lectin concentration. P. griseoroseum lectin in microgram concentrations stimulated proliferation of mice splenocytes. Thus, P. griseoroseum lectin exhibits potential mitogenicity, which can be exploited for further biomedical applications.

Ratiometric fluorophore for quantification of iodide under physiological conditions: applications in urine analysis and live cell imaging.

Dipod 1 bearing two pyrenyl tethered benzimidazolium moieties gives a fluorescence spectrum in aqueous medium which reveals a structured emission band between 330-400 nm and a broad emission band centered at 475 nm, respectively due to monomer and excimer emission of the pyrene moieties. The presence of an excimer emission band points to the formation of a pseudocyclic structure. Dipod 1 undergoes highly selective fluorescence quenching of the excimer emission band in the presence of iodide ions, whereas the fluorescence intensity of the monomer emission band remains stable. The ratio of fluorescence intensity I395 nm/I475 nmvs. log [I(-)] undergoes a linear change over a broad iodide concentration range of 10(-9) to 10(-5) M with KSV 3.7 × 10(5) M(-1). Dipod 1 can be used to determine iodide ions in urine samples, tap water and sea water conditions with 1 nM iodide as the lowest detection limit. On using paper strips coated with dipod 1, ∼1.7 pg cm(-2) iodide ions could be detected. Dipod 1 shows a fluorescence quenching response to 100 nM iodide ions in C6 glioma cells using confocal microscopy. The life time of the dipod 1 shows a linear decrease with log [I(-)] and points to coordination based recognition of iodide ion.

A catalytic chemodosimetric approach for detection of nanomolar cyanide ions in water, blood serum and live cell imaging.

Naphthimidazolium based monocationic chemodosimeters CD-1 and CD-2 undergo cyanide mediated catalytic transformation in the presence of cyanide ions (0.01% to 1% of CD-1/CD-2 concentrations) with a turnover number from 70 to 360. These chemodosimeters can detect as low as 0.5 nM and 1 nM cyanide ions under nearly physiological conditions (HEPES buffer-DMSO (5%), pH 7.4). The structures of CD-1 and its cyanide induced hydrolyzed product 4 have been confirmed by single crystal X-ray crystallography. CD-1 can also be used for the determination of 2 nM cyanide in the presence of blood serum. CD-1 and CD-2 also find applications in live cell imaging of 10 nM cyanide ions in rat brain C6 glioma cells. To the best of our knowledge, this is the first report where high sensitivity towards cyanide ions has been achieved through catalytic hydrolysis of the fluorescent chemodosimeter.

Microbial lectins and their prospective mitogenic potential.

The binding of mitogenic lectins to the glycoconjugates on cell surface receptor triggers multitude of reactions involving different signal transduction pathways which ultimately results in cell proliferation. Since 1960 after the chance discovery of mitogenic property of lectins by Nowell, it has attracted more attention. The property of stimulation of mature lymphocytes aided the immunological investigations to study and analyse the mechanism of cell stimulation and division. Plant lectins are extensively studied for mitogenic activity and their widespread applications are also reported. During the past two decades, the study of biological properties of microbial lectins has increased tremendously. Their biological activities including mitogenic potential are equally applicable as that of plant lectins. The review mainly focuses on mitogenic potential of microbial lectins. It will provide a comprehensive view regarding distribution of this remarkable property among microbes including algae, fungi and bacteria, mechanisms and models of mitogenic stimulation, and also assays being employed to detect the mitogenic activity.

Nanomolar fluorogenic detection of Al(III) by a series of Schiff bases in an aqueous system and their application in cell imaging.

Three positional isomers of a Schiff base containing -OH as end groups have been synthesized and evaluated for selective Al(III) detection due to inhibition of ESIPT, PET and activation of CHEF in 70% aqueous medium. Devoid of any conventional fluorophore, these sensors have nanomolar detection limits with high quantum yields and naked eye sensing of Al(III). Moreover, these probes have been demonstrated to enable the Al(III) detection in live human HeLa cells and rat C6 glioma cells using a confocal microscope.

Improvement of qualitative and quantitative traits in cotton under normal and stressed environments using genomics and biotechnological tools: A review.

Due to the increasing demand for high-quality and high fiber-yielding cotton (Gossypium spp.), research into the development of stress-resilient cotton cultivars has acquired greater significance. Various biotic and abiotic stressors greatly affect cotton production and productivity, posing challenges to the future of the textile industry. Moreover, the content and quality of cottonseed oil can also potentially be influenced by future environmental conditions. Apart from conventional methods, genetic engineering has emerged as a potential tool to improve cotton fiber quality and productivity. Identification and modification of genome sequences and the expression levels of yield-related genes using genetic engineering approaches have enabled to increase both the quality and yields of cotton fiber and cottonseed oil. Herein, we evaluate the significance and molecular mechanisms associated with the regulation of cotton agronomic traits under both normal and stressful environmental conditions. In addition, the importance of gossypol, a toxic phenolic compound in cottonseed that can limit consumption by animals and humans, is reviewed and discussed.

A naphthalimide-tyrosine-based dicationic amphiphile for intracellular 'turn-on' simultaneous detection of ATP and CTP.

We have developed a new naphthalimide-based amphiphile (YN-1) for the simultaneous detection of ATP and CTP. In YN-1, the cationic tyrosine-linked polyamine (+2 charge, hydrophilic unit) is appended at the -peri position of naphthalimide (hydrophobic unit). YN-1 and its Boc-protected compound 4 were characterized using state-of-the-art spectroscopic and optical techniques such as NMR, IR, UV-vis and fluorescence. The fluorescence data revealed that YN-1 showed a 'turn-on' (λem = 440 nm) fluorescence response for nanomolar detection of nucleoside triphosphates such as ATP and CTP in 20% HEPES buffer-DMSO solution. YN-1 also showed a concentration-based discrimination between ATP and CTP. YN-1 has been successfully applied for bioimaging of nucleoside triphosphates in MCF-7 live cancer cells with good compatibility. Therefore, the important findings from the present work will provide insight for future development of fluorescent probes to detect various kinds of essential nucleoside triphosphates.

Mushroom lectins in biomedical research and development.

Lectins are unique biorecognition proteins which recognize and interact with various cell surface carbohydrates/glycoproteins. These ubiquitous molecules are involved in various cell-cell interactions and can be exploited to analyze cell surface associated interactions and biological functions. Amongst fungi, lectins have been extensively explored from mushrooms as compared to microfungi or yeasts. Lectins from basidiomycetes have diverse features in terms of their physico-chemical characteristics and carbohydrate specificity. A plethora of lectins from genera Aleuria, Agrocybe, Boletus, Pleurotus, Russula, Schizophyllum, Volvariella, etc. exhibit potential applications in biomedical field. The current review summarizes the potential sources and characteristics of mushroom lectins. Potential involvement of mushroom lectin as anticancer, mitogenic, antiviral, antimicrobial, antioxidant and therapeutic agents has been discussed.

Structural aspects and biomedical applications of microfungal lectins.

Lectins are unique biorecognition molecules that identify cell surface carbohydrates/glycoproteins and play significant role in various interactions. They are ubiquitous glycan-specific proteins/glycoproteins of non-immune origin. Amongst microfungi, lectins have been widely reported from aspergilli, penicilli, Fusarium sp., etc., however a plethora of genera still remains unexplored. Microfungal lectins have wide diversity in their haemagglutination and carbohydrate specificity. They also exhibit great variations in their structural organization which influences lectin-glycan interactions. The present review summarizes the sources, characteristics and structural diversity of microfungal lectins. Prospective biomedical applications of microfungal lectins as anticancer, mitogenic, immunomodulatory, antioxidant and therapeutic agents have been discussed extensively.

Purification and characterization of a heterodimeric mycelial lectin from Penicillium proteolyticum with potent mitogenic activity.

In the present study, Penicillium proteolyticum lectin was purified by DEAE-Sepharose chromatography followed by Sephadex G-100 gel filtration chromatography. A sequence of ion-exchange and gel filtration chromatography resulted in 52.30 fold purified lectin with a high yield of 84.21%. The purified P. proteolyticum lectin is a glycoprotein with 2.83% linked carbohydrates. A single band in Native-PAGE, whereas two bands (25.1 kDa and 22.9 kDa) in SDS-PAGE confirmed the heterodimeric nature of the purified lectin. The apparent molecular weight (48 kDa) of P. proteolyticum lectin was further confirmed by gel filtration analysis. Heterodimeric P. proteolyticum lectin was stable within a pH range of 6.5-7.5 and upto a temperature of 30 °C. The lectin activity was strongly inhibited by complex glycoproteins and denaturants. Metal ions are not required for agglutination activity of purified lectin. The lectin showed significant mitogenic response towards mice splenocytes. It exhibited highest mitogenic activity at a concentration of 50 µg/mL. This is a first report on characteristics of purified P. proteolyticum lectin having potent mitogenic potential.

Lectins from red algae and their biomedical potential.

Lectins are unique proteins or glycoproteins of non-immune origin that bind specifically to carbohydrates. They recognise and interact reversibly to either free carbohydrates or glycoconjugates, without modifying their structure. Lectins are highly diverse and widely distributed in nature and have been extensively reported from various red algae species. Numerous red algae species have been reported to possess lectins having carbohydrate specificity towards complex glycoproteins or high-mannose N-glycans. These lectin-glycan interactions further trigger many biochemical responses which lead to their extensive use as valuable tools in biomedical research. Thus, owing to their exceptional glycan recognition property, red algae lectins are potential candidate for inhibition of various viral diseases. Hence, the present report integrates existing information on the red algae lectins, their carbohydrate specificity, and characteristics of purified lectins. Further, the review also reports the current state of research into their anti-viral activity against various enveloped viruses such as HIV, hepatitis, influenza, encephalitis, coronavirus and herpes simplex virus and other biomedical activities such as anti-cancer, anti-microbial, anti-inflammatory, anti-nociceptive and acaricidal activities.

Purification and characterization of a mitogenic lectin from Penicillium duclauxii.

Lectins are proteins/glycoproteins of non-immune origin which interact specifically and non-covalently with carbohydrate moieties on the cell surface. In this study, a lectin was purified from Penicillium duclauxii by ion-exchange chromatography on DEAE-Sepharose and gel filtration chromatography on a Sephadex G-100 column. An overall recovery of 94.11% and 60-fold purification was achieved. The purified lectin had a molecular weight of 54.9 kDa and was found to be heterogeneous as revealed by double band of sub-units with molecular mass of 21.13 kDa and 33.26 kDa, under reducing conditions. It is a glycoprotein with carbohydrate content of 3.95%. Lectin induced haemagglutination of erythrocytes was inhibited strongly by glycoproteins such as bovine submaxillary mucin, porcine stomach mucin and fetuin. The maximum haemagglutinating activity of P. duclauxii lectin was maintained after incubation at a temperature and pH range of 20-35 °C and 6.0-8.0, respectively. The haemagglutinating activity of P. duclauxii lectin was unaffected by EDTA and various metal ions. The purified P. duclauxii lectin exhibited maximum mitogenic activity towards mouse splenocytes at a concentration of 75 µg/mL. This manuscript reports a novel lectin from P. duclauxii with potent mitogenic activity towards mouse splenocytes.

Co-application of 6-ketone type brassinosteroid and metal chelator alleviates cadmium toxicity in B. juncea L.

Plant growth regulator-assisted phytoremediation has been assessed as a novel strategy to improve phytoremediation potential of plants. In the present work, potential of castasterone, a plant growth regulator, combined with citric acid was explored for phytoremediation of cadmium in Brassica juncea seedlings. The seedlings were raised under controlled laboratory conditions for 7 days. Results revealed that 0.6 mM cadmium exposure induced toxicity in the seedlings, which was reflected through root growth inhibition, accumulation of hydrogen peroxide and malondialdehyde, and loss of cell viability. Pre-sowing treatment of castasterone supplemented with citric acid enhanced cadmium accumulation in the roots (from 752 µg/g DW to 1192 µg/g DW) and shoots (from 88 µg/g DW to 311 µg/g DW) and also improved root length, shoot length, fresh weight, and dry weight of seedlings by 81, 17, 39, and 35 %, respectively. The co-application reduced malondialdehyde accumulation by 39 % and reduced oxidative stress by enhancing the activities of antioxidant enzymes (superoxide dismutase, guaiacol peroxidase, catalase, ascorbate peroxidase, dehydroascorbate, glutathione reductase, glutathione peroxidase, glutathione-S-transferase, polyphenol oxidase), maximum enhancement (82 %) being in polyphenol oxidase. Similarly, the contents of water- and lipid-soluble antioxidants were found to increase by 31 and 4 %, respectively. Confocal microscopy revealed enhanced content of NO. Results suggested that binary combination of castasterone and citric acid is helpful in improving cadmium accumulation and ameliorating metal toxicity in B. juncea seedlings.

Cyanobacterial lectins characteristics and their role as antiviral agents.

Lectins are ubiquitous proteins/glycoproteins of non-immune origin that bind reversibly to carbohydrates in non-covalent and highly specific manner. These lectin-glycan interactions could be exploited for establishment of novel therapeutics, targeting the adherence stage of viruses and thus helpful in eliminating wide spread viral infections. Here the review focuses on the haemagglutination activity, carbohydrate specificity and characteristics of cyanobacterial lectins. Cyanobacterial lectins exhibiting high specificity towards mannose or complex glycans have potential role as anti-viral agents. Prospective role of cyanobacterial lectins in targeting various diseases of worldwide concern such as HIV, hepatitis, herpes, influenza and ebola viruses has been discussed extensively. The review also lays emphasis on recent studies involving structural analysis of glycan-lectin interactions which in turn influence their mechanism of action. Altogether, the promising approach of these cyanobacterial lectins provides insight into their use as antiviral agents.

Protozoa lectins and their role in host-pathogen interactions.

Lectins are proteins/glycoproteins of non-immune origin that agglutinate red blood cells, lymphocytes, fibroblasts, etc., and bind reversibly to carbohydrates present on the apposing cells. They have at least two carbohydrate binding sites and their binding can be inhibited by one or more carbohydrates. Owing to carbohydrate binding specificity of lectins, they mediate cell-cell interactions and play role in protozoan adhesion and host cell cytotoxicity, thus are central to the pathogenic property of the parasite. Several parasitic protozoa possess lectins which mediate parasite adherence to host cells based on their carbohydrate specificities. These interactions could be exploited for development of novel therapeutics, targeting the adherence and thus helpful in eradicating wide spread of protozoan diseases. The current review highlights the present state knowledge with regard to protozoal lectins with an emphasis on their haemagglutination activity, carbohydrate specificity, characteristics and also their role in pathogenesis notably as adhesion molecules, thereby aiding the pathogen in disease establishment.

Amoebiasis vaccine development: A snapshot on E. histolytica with emphasis on perspectives of Gal/GalNAc lectin.

Amoebiasis/amebiasis is a gastrointestinal infection caused by an enteric dwelling protozoan, Entamoeba histolytica. The disease is endemic in the developing world and is transmitted mainly via the faecal-oral route (e.g., in water or food) and may or may not be symptomatic. This disease of socio-economic importance worldwide involves parasite adherence and cytolysis of human cells followed by invasion that is mediated by galactose-binding (Gal/GalNAc) surface lectin. Disruption of the mucus layer leads to invasive intestinal and extraintestinal infection. Gal-lectin based vaccinations have conferred protection in various animal models against E. histolytica infections. Keeping in view the pivotal role of Gal/GalNAc lectin in amoebiasis vaccine development, its regulation, genomic view of the parasite involving gene conversion in lectin gene families, current knowledge about involvement of Gal/GalNAc lectin in adherence, pathogenicity, signalling, encystment, generating host immune response, and in turn protozoa escape strategies, and finally its role as effective vaccine candidate has been described. This review will help researchers to explore pathogenesis mechanism along with genomic studies and will also provide a framework for future amoebiasis vaccine development studies.

Self-assembled vesicle and rod-like aggregates of functionalized perylene diimide: reaction-based near-IR intracellular fluorescent probe for selective detection of palladium.

Herein, we report design, synthesis, and self-assembly of perylene diimide (PDI) based near-IR intracellular probe (PS-PDI). PS-PDI molecules undergo aggregation to form self-assembled nanospheres and nanorods morphology in THF : H2O (1 : 1) and DMSO : H2O (1 : 9), respectively. The nanospheres have an open hole on surface reminiscent of vesicle structure (with a diameter of internal void in the range of 20-25 nm) whereas lengths of the nanorods extended up to few µm range. The Pd0 based depropargylation leads to de-aggregation of these PS-PDI aggregates into smaller spherical aggregates as evidenced by DLS, SEM, and TEM studies. Interestingly, these aggregates of PS-PDI in solution show highly sensitive behavior in the presence of Pd0 showing absorbance changes in NIR region (λmax = 710 nm) and quenching of emission at λem 630 nm (DMSO : H2O, 1 : 9) with a limit of detection = 6.6 × 10-9 M or at λem 564 nm (THF : H2O, 1 : 1) with limit of detection = 2.1 × 10-8 M. Time and concentration dependent kinetics profiles of PS-PDI aggregates revealed an impressive rate constant value of 0.4 s-1 and 0.21 s-1 (DMSO : H2O, 1 : 9), respectively in fluorescence and UV-Vis spectroscopy using 2 × 10-5 M concentration of Pd0. PS-PDI undergoes rapid internalization into HeLa cells with low cytotoxicity and was successfully used as an intracellular imaging reagent for Pd0 in live HeLa cells. For practical applications, we exploited these nano-aggregates of PS-PDI for estimation of Pd2+ in the presence of a NaBH4-PPh3 mixture, Pd0 in drug and environmental samples, and Pd2+ in urine samples with excellent selectivity and sensitivity.

Bay functionalized perylenediimide as a deaggregation based intracellular fluorescent probe for perchlorate.

The aggregates of perylenediimide based chemosensor (PDI 1) undergo de-aggregation induced fluorescence quenching selectively with ClO4(-) ions both in the solution and in the solid phase and can detect ClO4(-) ions in drinking water and fireworks. PDI 1 is permeable to C6 glioma cells, and ClO4(-) can be detected using confocal microscopy.