Bi(OTf)-promoted direct activation of formidable per-O-acetylated ʟ-rhamnose Donor: Stereoselective access to α-ʟ-rhamnopyranosides.

Rare ʟ-hexoses, including deoxy ʟ-hexoses, serve as potential chemical probes for carbohydrate-based drug discovery and vaccine development. 6-Deoxy sugars, particularly ʟ-rhamnose, are essential components of bacterial surface glycans, playing a key role in pathogen-host cell recognition and various physiological functions. Herein, we present an alternative and highly efficient ʟ-rhamnosylation utilizing the milder oxo-philic Bi(OTf) as the promoter, enabling the assembly of biologically significant α-ʟ-rhamnopyranosides in good yields.

Influence of C-4 Configuration and Neighboring Group/Remote Group Participation (NGP/RGP) Driven Conformational Evidence in Chemoselective Activation of Glycals.

We herein reveal the possibility of the C-4 neighboring group/remote group participation (NGP/RGP) facilitating the stabilization of the anomeric center via dioxolenium intermediates in the chemoselective activation of glycal donors. We further realized that the configuration of the C-4 group in the galacto- and gluco-glycal series enables diverse pathways to give direct 1,2-addition or Ferrier rearrangement, respectively. A proof-of-principle for stereoselective glycosylation was amply illustrated by employing carbohydrates, amino acids, natural products, and bioactive molecules to develop 2-deoxy-glycan analogs.

Reagent-controlled chemo/stereoselective glycosylation of ʟ-fucal to access rare deoxysugars.

2,6-Dideoxy sugars constitute an important class of anticancer antibiotics natural products and serve as essential medicinal tools for carbohydrate-based drug discovery and vaccine development. In particular, 2-deoxy ʟ-fucose or ʟ-oliose is a rare sugar and vital structural motif of several potent antifungal and immunosuppressive bioactive molecules. Herein, we devised a reagent-controlled stereo and chemoselective activation of ʟ-fucal, enabling the distinctive glycosylation pathways to access the rare ʟ-oliose and 2,3-unsaturated ʟ-fucoside.

Protecting group enabled stereocontrolled approach for rare-sugars talose/gulose via dual-ruthenium catalysis.

We herein report a convenient and highly stereocontrolled approach for rare and vital ᴅ-talo and ᴅ-gulo sugars directly from economical ᴅ-galactal through dual ruthenium-catalysis. The stereo-divergent strategy involves Ru(III)Cl-catalyzed Ferrier glycosylation of ᴅ-galactal to give 2,3-unsaturated ᴅ-galactopyranoside, further selective functionalization of C-4 and C-6 position with diverse protecting groups and dihydroxylation with Ru(VIII)O generated in situ providing access to talo/gulo isomers. The α-anomeric stereoselectivity and syn-diastereoselectivity in glycosylation-dihydroxylation steps have been predominantly achieved by judicious selection of stereoelectronically diverse protecting groups.

MeSI-promoted chemoselective deacetylation: a general and mild protocol.

A MeSI-mediated simple and efficient protocol for the chemoselective deprotection of acetyl groups has been developed employing KMnO as an additive. This chemoselective deacetylation is amenable to a wide range of substrates, tolerating diverse and sensitive functional groups in carbohydrates, amino acids, natural products, heterocycles, and general scaffolds. The protocol is attractive because it uses an environmentally benign reagent system to perform quantitative and clean transformations under ambient conditions.

Bismuth-Catalyzed Stereoselective 2-Deoxyglycosylation of Disarmed/Armed Glycal Donors.

Bi(OTf) promoted direct and highly stereoselective glycosylation of "disarmed" and "armed" glycals to synthesize 2-deoxyglycosides has been reported. The tunable and solvent-controlled chemoselective activation of deactivated glycal donors distinguishing the competitive Ferrier and 1,2-addition pathways was discovered to improve substrate scope. The practical versatility of the method has been amply demonstrated with the oligosaccharide syntheses and 2-deoxyglycosylation of high-value natural products and drugs.

Selective Azidooxygenation of Alkenes Enabled by Photo-induced Radical Transfer Using Aryl-λ-azidoiodane Species.

The photolytic radical-induced vicinal azidooxygenation of synthetically important and diverse functionalized substrates including unactivated alkenes is reported. The photoredox-catalyst/additive-free protocol enables intermolecular oxyazidation by simultaneously incorporating two new functionalities; and across the double bond in a selective manner. Mechanistic investigations reveal the intermediacy of the azidyl radical facilitated the photolysis of λ-azidoiodane species and cascade proceeding to generate an active carbon-centered radical.

Copper(ii)-catalyzed stereoselective 1,2-addition vs. Ferrier glycosylation of "armed" and "disarmed" glycal donors.

Selective activation of "armed' and ''disarmed" glycal donors enabling the stereo-controlled glycosylations by employing Cu(ii)-catalyst as the promoter has been realized. The distinctive stereochemical outcome in the process is mainly influenced by the presence of diverse protecting groups on the donor and the solvent system employed. The protocol is compatible with a variety of aglycones including carbohydrates, amino acids, and natural products to access deoxy-glycosides and glycoconjugates with high α-anomeric selectivity.

Photoswitchable Regiodivergent Azidation of Olefins with Sulfonium Iodate(I) Reagent.

Photoswitchable strategy for selective azidation of structurally diverse olefins under transition-metal-free conditions is reported. The unprecedented reactivity of trimethylsulfonium [bis(azido)iodate(I)] species under visible light allows radical azidooxygenation of the C═C π bond with distinctive selectivity. In the absence of visible light, the reaction proceeds through an ionic intermediate which led to complementary regioselectivity to provide α-alkyl azides.

Visible-light activated metal catalyst-free vicinal diazidation of olefins with sulfonium iodate(i) species.

A visible light-induced vicinal diazidation of various alkenes using stable sulfonium bis(acetoxy)iodate(i) and sodium azide as a radical precursor is described. The trimethylsulfonium [bis(azido)iodate(i)] species, intrinsically generated in situ, demonstrated unprecedented reactivity toward C[double bond, length as m-dash]C π bond-promoting selective azidation under photochemical conditions without any photoredox or metal catalyst. The visible-light stimulated diazidation reaction provides a convenient and straightforward approach to highly prevalent vicinal nitrogen scaffolds of myriad therapeutic importance.

MNK1 inhibitor as an antiviral agent suppresses buffalopox virus protein synthesis.

A small molecule chemical inhibitor CGP57380 that blocks activation of MAPK interacting kinase 1 (MNK1) was found to significantly suppress buffalopox virus (BPXV) replication. BPXV infection was shown to induce MNK1 activation. Depletion of MNK1 by small interfering RNA (siRNA), blocking activation of extracellular regulated kinase (ERK, an upstream activator of MNK1) and disruption of eIF4E/eIF4G interaction (downstream substrate of MNK1 which plays a central role in cap-dependent translation initiation), resulted in reduced BPXV replication, suggesting that ERK/MNK1/eIF4E signaling is a prerequisite for BPXV replication.

Typing of isolated from poultry on the basis of A-RFLP by various restriction enzymes.

RFLP analysis of the flagellin (A) gene was compared using three different restriction endonucleases I, I and II to determine the genetic diversity among 43 isolates of poultry origin from the same geographical area. A gene was amplified in all the isolates and RFLP analysis showed variations. -based RFLP was found most efficient in discriminating isolates by generating 15 different -RFLP patterns with discriminatory index (D.

Role of MAPK/MNK1 signaling in virus replication.

Viruses are obligate intracellular parasites; they heavily depend on the host cell machinery to effectively replicate and produce new progeny virus particles. Following viral infection, diverse cell signaling pathways are initiated by the cells, with the major goal of establishing an antiviral state. However, viruses have been shown to exploit cellular signaling pathways for their own effective replication.

Temporal variations in patterns of strain diversity and antimicrobial resistance in the migrant Egyptian vulture.

: Multiple antimicrobial resistance in of wild vertebrates is a global concern with scarce assessments on the subject from developing countries that have high human-wild species interactions. We studied the ecology of in a wintering population of Egyptian Vultures in India to understand temporal changes in both strains and patterns of antimicrobial resistance. : We ribotyped strains and assessed antimicrobial resistance from wintering vultures at a highly synanthropic carcass dump in north-west India.

Chemoselective and stereospecific iodination of alkynes using sulfonium iodate(i) salt.

An efficient and highly chemoselective iodination of alkynes using a sulfonium iodate(i) electrophilc reagent under metal-free conditions has been realized. The reactivity of sulfonium iodate(i) salt could be significantly diverse in the presence of water as the solvent, enabling the (E)-1,2-diiodoalkenes stereospecifically. This stereodivergent approach is amenable to a wide range of alkyne substrates and demonstrates a diverse functional group tolerance resulting in synthetically valuable 1-iodoalkyne and (E)-vicinal-diiodoalkenes in good to excellent yields (up to 99%) with 100% selectivity under ambient conditions.

β-defensins: An innate defense for bovine mastitis.

Immune challenges are inevitable for livestock that are exposed to a varied range of adverse conditions ranging from environmental to pathogenic stresses. The β-defensins are antimicrobial peptides, belonging to "defensin" family and therefore acts as the first line of defense against the major infections occurring in dairy cattle including intramammary infections. The better resistance to mastitis displayed by is implicit in the fact that they have better adapted and also has more sequence variation with rare allele conserved due to lesser artificial selection pressure than that of .

Regioselective vicinal functionalization of unactivated alkenes with sulfonium iodate(i) reagents under metal-free conditions.

Metal-free, molecular iodine-free direct 1,2-difunctionalization of unactivated alkenes has been reported. The sulfonium iodate(i) reagent efficiently promoted the intermolecular vicinal iodo-functionalization of a diverse range of olefins in a stereo and regioselective manner. This method enables the divergent and straightforward preparation of synthetically useful functionalities; β-iodocarboxylates, β-iodohydrins, and β-iodoethers in a one-step process.

Identification and in silico analysis of cattle DExH/D box RNA helicases.

The helicases are motor proteins participating in a range of nucleic acid metabolisms. RNA helicase families are characterized by the presence of conserved motifs. This article reports a comprehensive in silico analysis of Bos taurus DExH/D helicase members.

Ruthenium Catalyzed Stereo/Chemo/Regioselective One-Pot Synthesis of C(2)-C(3) Unsaturated and α-D-Mannopyranosyl Sulfones.

An efficient and divergent approach to C(2)-C(3) unsaturated glycosyl and α-D-mannopyranosyl sulfones has been developed via ruthenium-promoted direct glycosylation, oxidation, and dihydroxylation from glycal in one-pot. The presence of stoichiometric amounts of NaIO4 and in situ generation of RuO4 from a RuCl3-NaIO4 reagent system were crucial for chemoselective oxidation of sulfide in the presence of an olefin moiety. The dual-role of ruthenium in sequential glycosylation-oxidation-dihydroxylation is amenable to a wide range of thio acceptors to access α-D-mannopyranosyl sulfones in good yields with high regioselectivity.

Ruthenium catalyzed synthesis of 2,3-unsaturated C-glycosides from glycals.

A highly efficient and convenient C-glycosylation method was developed using ruthenium(III) chloride for the synthesis of 2,3-unsaturated C-glycosides. Various nucleophiles such as allyl trimethylsilane, triethylsilane, trimethylsilyl cyanide, trimethylsilyl azide and heterocycles such as thiophene and furan reacted smoothly with glycals in the presence of catalytic amount of ruthenium trichloride under mild reaction conditions.

Peste des petits ruminants virus infection of small ruminants: a comprehensive review.

Peste des petits ruminants (PPR) is caused by a Morbillivirus that belongs to the family Paramyxoviridae. PPR is an acute, highly contagious and fatal disease primarily affecting goats and sheep, whereas cattle undergo sub-clinical infection. With morbidity and mortality rates that can be as high as 90%, PPR is classified as an OIE (Office International des Epizooties)-listed disease.

Using 'biased-privileged' scaffolds to identify lysine methyltransferase inhibitors.

Methylation of histones by lysine methyltransferases (KMTases) plays important roles in regulating chromatin function. It is also now clear that improper KMTases activity is linked to human diseases, such as cancer. We report an approach that employs drug-like 'privileged' scaffolds biased with motifs present in S-adenosyl methionine, the cofactor used by KMTases, to efficiently generate inhibitors for Set7, a biochemically well-characterized KMTase.

Examining the mechanism of action of a kinesin inhibitor using stable isotope labeled inhibitors for cross-linking (SILIC).

It is difficult to determine a chemical inhibitor's binding site in multiprotein mixtures, particularly when high-resolution structural studies are not straightforward. Building upon previous research involving photo-cross-linking and the use of mixtures of stable isotopes, we report a method, Stable Isotope Labeled Inhibitors for Cross-linking (SILIC), for mapping a small molecule inhibitor's binding site in its target protein. In SILIC, structure-activity relationship data is used to design inhibitor analogues that incorporate a photo-cross-linking group along with either natural or 'heavy' stable isotopes.

Dendritic effect of ligand-coated nanoparticles: enhanced apoptotic activity of silica-berberine nanoconjugates.

We describe the synthesis and biological characterization of a novel prototype, namely, silica nanoconjugates bearing a covalently linked berberine, a plant alkaloid known to have antiproliferative activity. The effect of synthesized nanoconjugates on cell proliferation, the cell cycle profile, and apoptosis in the human cervical carcinoma cell line (HeLa), human hepatocellular liver carcinoma cell line (HepG2), and human embryonic kidney (HEK) 293T cell line has been studied and compared with the results obtained for free berberine. Our results show that all the nanoconjugates display higher antiproliferative activity than free berberine.

Propargyl glycosides as stable glycosyl donors: anomeric activation and glycoside syntheses.

The advantages of stable glycosyl donors for saccharide coupling are many, and we describe herein the utility of propargyl glycosides for anomeric activation and glycoside synthesis exploiting the alkynophilicity of AuCl3. Various aglycones were reacted with propargyl glycosides, resulting in the formation of an alpha,beta-mixture of glycosides and disaccharides in good yields.