Correction: A spiropyran-coumarin platform: an environment sensitive photoresponsive drug delivery system for efficient cancer therapy

Correction for 'A spiropyran-coumarin platform: an environment sensitive photoresponsive drug delivery system for efficient cancer therapy' by Shrabani Barman et al., J. Mater. Chem. B, 2017, DOI: 10.1039/c7tb00379j.

A spiropyran–coumarin platform: an environment sensitive photoresponsive drug delivery system for efficient cancer therapy

In spite of inventing several anticancer agents the clinical payoff still remains unsatisfactory because of their severe host toxicity due to their nonspecific biodistribution in the body.

Tailor-Made Temperature-Sensitive Micelle for Targeted and On-Demand Release of Anticancer Drugs

The design of nanomedicines from the tuned architecture polymer is a leading object of immense research in recent years. Here, smart thermoresponsive micelles were prepared from novel architecture four-arm star block copolymers, namely, pentaerythritol polycaprolactone-b-poly(N-isopropylacrylamide) and pentaerythritol polycaprolactone-b-poly(N-vinylcaprolactam). The polymers were synthesized and tagged with folic acid (FA) to render them as efficient cancer cell targeting cargos. FA-conjugated block copolymers were self-assembled to a nearly spherical (ranging from 15 to 170 nm) polymeric micelle (FA-PM) with a sufficiently lower range of critical micelle concentration (0.59 × 10(-2) to 1.52 × 10(-2) mg/mL) suitable for performing as an efficient drug carrier. The blocks show lower critical solution temperature (LCST) ranging from 30 to 39 °C with high DOX-loading content (24.3%, w/w) as compared to that reported for a linear polymer in the contemporary literature. The temperature-induced reduction in size (57%) of the FA-PM enables a high rate of DOX release (78.57% after 24 h) at a temperature above LCST. The DOX release rate has also been tuned by on-demand administration of temperature. The in vitro biocompatibilities of the blank and DOX-loaded FA-PMs have been studied by the MTT assay. The cellular uptake study proves selective internalization of the FA-PM into cancerous cells (C6 glioma) compared that into normal cells (HaCaT). In vivo administration of the DOX-loaded FA-PMs into the C6 glioma rat tumor model resulted in significant accumulation in tumor sites, which drastically inhibited the tumor volume by ∼83.9% with respect to control without any significant systemic toxicity.

AMPK-mediated crosstalk of heteroglycan-induced reactive species and autophagic cascade in RAW 264.7 cells

AMPK mediates the crosstalk among heteroglycan-induced autophagy and reactive species in RAW 264.7 cells.

Bio-functionalization of magnetite nanoparticles using an aminophosphonic acid coupling agent: new, ultradispersed, iron-oxide folate nanoconjugates for cancer-specific targeting

The present study describes a systematic approach towards the design and development of novel, bio-functionalized, magneto-fluorescent nanoparticles for cancer-specific targeting. Biocompatible, hydrophilic, magneto-fluorescent nanoparticles with surface-pendant amine, carboxyl or aldehyde groups, to be later used for bio-conjugation, were designed using an aminophosphonic acid coupling agent. These magneto-fluorescent nanoparticles were further functionalized with folic acid, using diverse conjugation strategies. A series of new iron-oxide folate nanoconjugates with excellent aqueous dispersion stability and reasonably good hydrodynamic sizes under a wide range of physiological conditions were developed. These ultradispersed nanosystems were analyzed for their physicochemical properties and cancer-cell targeting ability, facilitated by surface modification with folic acid. The nanoparticle size, charge, surface chemistry, magnetic properties and colloidal stability were extensively studied using a variety of complementary techniques. Confocal microscopy, performed with folate receptor positive human cervical HeLa cancer cells, established that these non-cytotoxic iron-oxide folate nanoconjugates were effectively internalized by the target cells through receptor-mediated endocytosis. Cell-uptake behaviors of nanoparticles, studied using magnetically activated cell sorting (MACS), clearly demonstrated that cells over-expressing the human folate receptor internalized a higher level of these nanoparticle-folate conjugates than negative control cells.

Transient expression, purification and characterization of bioactive human fibroblast growth factor 8b in tobacco plants

cDNA of human fibroblast growth factor 8 isoform b (FGF8b) was cloned for the first time into a plant expression vector with or without endoplasmic reticulum retention signal (KDEL) and was transiently expressed as His tagged fusion protein in Nicotiana tabacum leaves through Agrobacterium mediated gene transfer by vacuum infiltration method. Expression of FGF8b was confirmed by ELISA and Western blot using anti-FGF8b antibody and the expression level was measured as 4.1% of total soluble protein of tobacco leaves. The expressed recombinant protein was purified by Ni-NTA affinity chromatography and its molecular weight was determined by MALDI-TOF-MS. Schiff's test, Concanavalin A (Con A) immunoblot and enzymatic deglycosylation indicated that the high molecular mass was due to glycosylation of the FGF8b expressed in plant cells. Measurement of its biological activity in NIH3T3 cells by thymidine incorporation and MTT assay showed induction of cell proliferation. These results indicate that biologically active recombinant FGF8b could be expressed in tobacco plants.

Biocompatibility of diamond-like nanocomposite thin films

Diamond-like nanocomposite (DLN) films consist of network structure of amorphous carbon and quartz like silicon. In the present work, DLN films have been synthesized on pyrex glass and subsequently, their biocompatibility have been investigated through primary and secondary cell adhesion, cytotoxicity, protein adsorption and murine peritoneal macrophage activation experiments. Variable degree of cell and protein response have been found based on variable film synthesis parameters but in overall, required biocompatibility has been established for all types of film-coating.

Adjuvant effect of mushroom glucan and bovine lactoferrin upon Aeromonas hydrophila vaccination in catla, Catla catla (Hamilton)

Mushroom glucan and bovine lactoferrin (Lf), known for their immunostimulatory potential, were used as adjuvant in conjunction with a formalin-killed Aeromonas hydrophila vaccine in catla, Catla catla. In vitro antigen-specific responsiveness of catla leucocytes and protective responses against experimental challenge with homologous antigen were monitored following immunization. Antigen-specific proliferation, 'macrophage activating factor' (MAF) production and antibody production were significantly higher in fish injected with glucan adjuvanted vaccine. Lf adjuvanted preparations showed a weak proliferative response and MAF production, although the antibody production was significantly higher than the controls. A good degree of protection was achieved with the glucan adjuvanted vaccine. However, in spite of producing significant anti-A. hydrophila antibody, Lf adjuvanted vaccine did not confer any protection following challenge with A. hydrophila. The potential of adjuvanticity of mushroom glucan and bovine Lf in intraperitoneal vaccination is discussed.

CD4+ T-cell responses to recombinant hsp65 and hsp18 of M. leprae and their trypsin-digested fragments in leprosy: diversity in HLA-DR restriction

Mycobacterium leprae heat-shock proteins hsp65 and hsp18 have received immense attention as major T-cell target antigens in leprosy. Both of these hsps and their tryptic fragments were characterized for their ability to stimulate CD4+ T cells derived from polar leprosy cases and healthy contacts. The optimal digestion of hsps with trypsin yielded four fragments of hsp65--TDB65-1 (24 kDa), TDB65-2 (18 kDa), TDB65-3 (17 kDa), TDB65-4 (14 kDa)-- and three of hsp18--TDB18-1 (10 kDa), TDB18-2 (5 kDa), TDB18-3 (3 kDa). While all of these tryptic fragments and undigested hsps triggered CD4+ T cells from tuberculoid (TT) leprosy patients and healthy contacts (SI > 2), only two fragments--TDB65-2 and TDB18-3--were found to be stimulatory in anergic lepromatous (LL) leprosy patients (SI = 5.27 and 3.0, respectively). Blocking studies using allele-specific anti-DR monoclonal antibodies revealed multiple HLA-Dr restriction, with DR2 providing the strongest restriction in both TT as well as LL leprosy. These findings indicate that M. leprae hsps and their trypsin-digested fragments are promiscuous and recognizable in the context of diverse HLA alleles, of which DR2 is the most efficient restriction element. The 18-kDa fragment of hsp65 and the 3-kDa fragment of hsp18 are the most versatile fragments that could elicit in vitro proliferation in both polar forms of leprosy.

Microbial production of L-tyrosine: a review

Microbial production of L-tyrosine by direct fermentation and by enzymatic methods has been reviewed. Achievements in this regard made through recombinant DNA techniques have also been included. The review also includes biosynthesis and regulation of tyrosine.

Production of some extracellular enzymes by a lignin peroxidase-producing brown rot fungus, Polyporus ostreiformis, and its comparative abilities for lignin degradation and dye decolorization

Polyporus ostreiformis produced Mn peroxidase, acid protease, alpha-amylase, and lignin peroxidase, with maximum activities of 40, 8,300, and 4,200 U liter-1 and 50 nkat liter-1, respectively, in nitrogen-limited liquid media. The fungus removed only 18.6% lignin from rice straw in 3 weeks but effected 99% decolorization of Congo red dye in 9 days.

L-phenylalanine production by double auxotrophic mutants of Arthrobacter globiformis

A number of tryptophan-plus-tyrosine double auxotrophs have been isolated from a glutamate producing Arthrobacter globiformis excreting L-phenylalanine by two-step mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. For the three potent mutants tested the medium of Alföldi was found to be the best. The optimum tryptophan, tyrosine and biotin concentrations for phenylalanine production of these mutants were 0.5 mmol/L, 0.1 mmol/L and 5 micrograms/L, respectively. At these levels strain TT-39 yielded 2.6 g phenylalanine per L of medium in flask culture with glucose (350 mmol/L) and NH4Cl (60 mmol/L).

Purification and characterization of three toxins and two agglutinins from Abrus precatorius seed by using lactamyl-Sepharose affinity chromatography

Three toxins, abrin-I, -II, and -III, and two agglutinins, APA-I and -II, were purified from the seeds of Abrus precatorius by lactamyl-Sepharose affinity chromatography followed by gel filtration and DEAE-Sephacel column chromatography. Abrin-I did not bind on DEAE-Sephacel column chromatography and the bound abrin-II, abrin-III, APA-I, and APA-II were eluted with a sodium acetate gradient. The identity of each protein was established by sodium dodecylsulfate-polyacrylamide gel electrophoresis and isoelectric focusing. The relative molecular weights are abrin-I, 64,000; abrin-II and abrin-III, 63,000 each: APA-I, 130,000; and APA-II, 128,000. Isoelectric focusing revealed microheterogeneity due to the presence of isoforms in each protein. Toxicity and binding studies further confirmed the differences among the lectins. The time course of inhibition of protein synthesis in thymocytes by the toxins showed lag times of 78, 61, and 72 min with Ki's of 0.55, 0.99, and 0.74 ms-1 at a 0.63 nM concentration of each of abrin-I, -II, and -III, respectively. A Scatchard plot obtained from the equilibrium measurement for the lectins binding to lactamyl-Sepharose beads showed nonlinearity, indicating a cooperative mode of binding which was not observed for APA-I binding to Sepharose 4B beads. Further, by the criterion of the isoelectric focusing profile, it was shown that the least toxic abrin-I and the highly toxic abrin-II isolated by lactamyl-Sepharose chromatography were not retained on a low-affinity Sepharose 4B matrix, which signifies the necessity of using a high-affinity matrix for the purification of the lectins.

Microbial production of L-tryptophan: a review

Microbial production of L-tryptophan has been reviewed with 172 references. The review includes different tryptophan producing microorganisms, their optimal cultural conditions, yields, assay and process of recovery. It also includes a discussion on the pathway of tryptophan biosynthesis and its regulation. Achievements in this regard made through genetic engineering have also been included.

Microbial production of L-phenylalanine: a review

Microbial production of L-phenylalanine by direct fermentation and by substrate conversion has been reviewed. The review also includes a discussion on different other methods for phenylalanine production, their advantages and disadvantages with mutants and genetically tailored strains. Biosynthesis of phenylalanine, its regulation in hyperproducing strains and recovery of phenylalanine has been discussed in brief.