DP Property, RNP and Semiseparability

Pethe, Prakash,Thakare, Nimbakrishna Department of Mathematics 1977 Kyungpook mathematical journal Vol.17 No.1

Discovery of IPK6705, a potent clinical candidate for the treatment of MDR and XDR Tuberculosis

Kevin Pethe 한국실험동물학회 2012 한국실험동물학회 학술발표대회 논문집 Vol.2012 No.8

Synthetic, Characterization, Biological, Electrical and Catalytic Studies of Some Transition Metal Complexes of Unsymmetrical Quadridentate Schiff Base Ligand

Maldhure, A. K.,Pethe, G. B.,Yaul, A. R.,Aswar, A. S. Korean Chemical Society 2015 대한화학회지 Vol.59 No.3

Unsymmetrical tetradentate Schiff base N-(2-hydroxy-5-methylacetophenone)-N'-(2-hydroxy acetophenone) ethylene diamine (H₂L) and its complexes with Cr(III), Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) have been synthesized and characterized by elemental analyses, magnetic susceptibility measurements, IR, electronic spectra and thermogravimetric analyses. ¹H, ¹³C-NMR and FAB Mass spectra of ligand clearly indicate the presence of OH and azomethine groups. Elemental analyses of the complexes indicate that the metal to ligand ratio is 1:1 in all complexes. Infrared spectra of complexes indicate a dibasic quadridentate nature of the ligand and its coordination to metal ions through phenolic oxygen and azomethine nitrogen atoms. The thermal behavior of these complexes showed the loss of lattice water in the first step followed by decomposition of the ligand in subsequent steps. The thermal data have also been analyzed for the kinetic parameters by using Horowitz-Metzger method. The dependence of the electrical conductivity on the temperature has been studied over the temperature range 313-403 K and the complexes are found to show semiconducting behavior. XRD and SEM images of some representative complexes have been recorded. The antimicrobial activity of the ligand and its complexes has been screened against various microorganisms and all of them were found to be active against the test organisms. The Fe(III) and Ni(II) complex have been tested for the catalytic oxidation of styrene.

Biomaterials Regulate Mechanosensors YAP/TAZ in Stem Cell Growth and Differentiation

Virdi Jasmeet Kaur,Pethe Prasad 한국조직공학과 재생의학회 2021 조직공학과 재생의학 Vol.18 No.2

Tissue-resident stem cells are surrounded by a microenvironment known as ‘stem cell niche’ which is specific for each stem cell type. This niche comprises of cell-intrinsic and -extrinsic factors like biochemical and biophysical signals, which regulate stem cell characteristics and differentiation. Biochemical signals have been thoroughly studied however, the effect of biophysical signals on stem cell regulation is yet to be completely understood. Biomaterials have aided in addressing this issue since they can provide a defined and tuneable microenvironment resembling in vivo conditions. We review various biomaterials used in many studies which have shown a connection between biomaterialgenerated mechanical signals and alteration in stem cell behaviour. Researchers probed to understand the mechanism of mechanotransduction and reported that the signals from the extracellular matrix regulate a transcription factor yesassociated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ), which is a downstream-regulator of the Hippo pathway and it transduces the mechanical signals inside the nucleus. We highlight the role of the YAP/TAZ as mechanotransducers in stem cell self-renewal and differentiation in response to substrate stiffness, also the possibility of mechanobiology as the emerging field of regenerative medicines and three-dimensional tissue printing.

Metallo-collagenase production by Arthrobacter creatinolyticus KP015744

Savita A. Kate,Madhuri Sahasrabudhe,Archana Pethe Techno-Press 2022 Advances in environmental research Vol.11 No.1

Amongst 27 isolates from deteriorated leather samples, Arthrobacter creatinolyticus KP015744 zzx28 was found to be an efficient collagenase producer. Collagenase production of 13.33 µmoles/min was shown at an optimum temperature at 37℃ after 72h and at pH 7.5 by using 2 ml/dL inoculum in 10 mg/ml collagen peptide type I as a substrate. In presence of Hg²⁺, EDTA and 𝛽-mercaptoethanol the collagenase production by the isolate was strongly inhibited however Fe²⁺, Ca²⁺and DMSO enhanced production of the enzyme. Specific activity was found to be 19.46×10³ U/mg and molecular weight 66 kD by SDS PAGE. Isolate also has potential to hydrolyze keratin which is another important protein found in leather. Experimental results propose that collagenase can be effectively used as a tool for collagen and keratin rich solid waste treatment.

Next-generation antimicrobials: from chemical biology to first-in-class drugs

Michelle Lay Teng Ang,Paul Murima,Kevin Pethe 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.9

The global emergence of multi-drug resistantbacteria invokes an urgent and imperative necessity for theidentification of novel antimicrobials. The general lack ofsuccess in progressing novel chemical entities from targetbaseddrug screens have prompted calls for radical andinnovative approaches for drug discovery. Recent developmentsin chemical biology and target deconvolutionstrategies have revived interests in the utilization of wholecellphenotypic screens and resulted in several successstories for the discovery and development novel drugcandidates and target pathways. In this review, we presentand discuss recent chemical biology approaches focusingon the discovery of novel targets and new lead moleculesfor the treatment of human bacterial and protozoaninfections.

The invariant design of planar magnetron sputtering TFT-LCD

Yoo, W.J.,Demaray, E.,Hosokawa,Pethe, R. The Korean Vacuum Society 1999 Journal of Korean Vacuum Science & Technology Vol.3 No.2

The main consideration factor to design a magnetron of the sputtering system for TFT-LCD metallization is high sheet resistance (Rs) uniformity which is provided by the high target erosion and high current efficiency. The present study has developed a rectangular magnetron for TFT-LCD to bve considered full target erosion and high film uniformity. After an aluminum-2 at.% and alloy target was installed in a magnetron source and the film was deposited on the glass of 600${\times}$720 mm, the Rs uniformity of the deposited film was measured as functions of the magnet tilt and magnet scanning configuration. And the target erosion profile was observed with the target voltage. When sputtered at 4mtorr and 10kW, the magnet tilt for the high Rs uniformity of 8.38% was 7mm. The plasma voltage at the dwell home and end for full-face target erosion, when scanned the magnetron was 120% compared to the mean voltage of the other area.

Biosynthesis and Recycling of Nicotinamide Cofactors in<i>Mycobacterium tuberculosis</i> : <i>AN ESSENTIAL ROLE FOR NAD IN NONREPLICATING BACILLI</i>

Boshoff, Helena I. M.,Xu, Xia,Tahlan, Kapil,Dowd, Cynthia S.,Pethe, Kevin,Camacho, Luis R.,Park, Tae-Ho,Yun, Chang-Soo,Schnappinger, Dirk,Ehrt, Sabine,Williams, Kerstin J.,Barry III, Clifton E. American Society for Biochemistry and Molecular Bi 2008 The Journal of biological chemistry Vol.283 No.28

<P>Despite the presence of genes that apparently encode NAD salvage-specific enzymes in its genome, it has been previously thought that Mycobacterium tuberculosis can only synthesize NAD de novo. Transcriptional analysis of the de novo synthesis and putative salvage pathway genes revealed an up-regulation of the salvage pathway genes in vivo and in vitro under conditions of hypoxia. [14C]Nicotinamide incorporation assays in M. tuberculosis isolated directly from the lungs of infected mice or from infected macrophages revealed that incorporation of exogenous nicotinamide was very efficient in in vivo-adapted cells, in contrast to cells grown aerobically in vitro. Two putative nicotinic acid phosphoribosyltransferases, PncB1 (Rv1330c) and PncB2 (Rv0573c), were examined by a combination of in vitro enzymatic activity assays and allelic exchange studies. These studies revealed that both play a role in cofactor salvage. Mutants in the de novo pathway died upon removal of exogenous nicotinamide during active replication in vitro. Cell death is induced by both cofactor starvation and disruption of cellular redox homeostasis as electron transport is impaired by limiting NAD. Inhibitors of NAD synthetase, an essential enzyme common to both recycling and de novo synthesis pathways, displayed the same bactericidal effect as sudden NAD starvation of the de novo pathway mutant in both actively growing and nonreplicating M. tuberculosis. These studies demonstrate the plasticity of the organism in maintaining NAD levels and establish that the two enzymes of the universal pathway are attractive chemotherapeutic targets for active as well as latent tuberculosis.</P>

The invariant design of planar magnetron sputtering in TFT - LCD

W. J. Yoo,E. Demaray,A. Hosokawa,R. Pethe 한국진공학회(ASCT) 1999 Journal of Korean Vacuum Science & Technology Vol.3 No.2

The main consideration factor to design a magnetron of the sputtering system for TFf-LCD metallization is the high sheet resistance (R_s) uniformity which is provided by the high target erosion and high current efficiency. The present study has developed a rectangular magnetron for TFT-LCD to be considered full target erosion and high film uniformity. After an aluminum-2 at.% Nd alloy target was installed in a magnetron source and the film was deposited on the glass of 600×700 ㎜, the Rs uniformity of the deposited film was measured as functions of the magnet tilt and magnet scanning configuration. And the target erosion profile was observed with the target voltage. When sputtered at 4 mtorr and 10 ㎾, the magnet tilt for the high R_s uniformity of 8.38% was 7 ㎜. The plasma voltage at the dwell home and end for full-face target erosion, when scanned the magnetron was 120% compared to the mean voltage of the other area.

Isolation and Characterization of a Hybrid Respiratory Supercomplex Consisting of <i>Mycobacterium tuberculosis</i> Cytochrome <i>bcc</i> and <i>Mycobacterium smegmatis</i> Cytochrome <i>aa</i> ₃

Kim, Mi-Sun,Jang, Jichan,AB Rahman, Nurlilah Binte,Pethe, Kevin,Berry, Edward A.,Huang, Li-Shar American Society for Biochemistry and Molecular Bi 2015 The Journal of biological chemistry Vol.290 No.23

<▼1><P><B>Background:</B> Mycobacteria have no soluble cytochrome <I>c</I>; the electron transfer chain involves a Complex III-IV “supercomplex.”</P><P><B>Results:</B> Expression of the <I>M. tuberculosis</I> Complex III in <I>M. smegmatis</I> lacking native complex yields a functional hybrid supercomplex.</P><P><B>Conclusion:</B> This supercomplex is a dimer of protomers containing two each of hemes A, B, and C.</P><P><B>Significance:</B> This is the first purification of respiratory Complex III or IV from <I>Mycobacterium</I>.</P></▼1><▼2><P>Recently, energy production pathways have been shown to be viable antitubercular drug targets to combat multidrug-resistant tuberculosis and eliminate pathogen in the dormant state. One family of drugs currently under development, the imidazo[1,2-<I>a</I>]pyridine derivatives, is believed to target the pathogen's homolog of the mitochondrial <I>bc</I><SUB>1</SUB> complex. This complex, denoted cytochrome <I>bcc</I>, is highly divergent from mitochondrial Complex III both in subunit structure and inhibitor sensitivity, making it a good target for drug development. There is no soluble cytochrome <I>c</I> in mycobacteria to transport electrons from the <I>bcc</I> complex to cytochrome oxidase. Instead, the <I>bcc</I> complex exists in a “supercomplex” with a cytochrome <I>aa</I><SUB>3</SUB>-type cytochrome oxidase, presumably allowing direct electron transfer. We describe here purification and initial characterization of the mycobacterial cytochrome <I>bcc-aa</I><SUB>3</SUB> supercomplex using a strain of <I>M. smegmatis</I> that has been engineered to express the <I>M. tuberculosis</I> cytochrome <I>bcc</I>. The resulting hybrid supercomplex is stable during extraction and purification in the presence of dodecyl maltoside detergent. It is hoped that this purification procedure will potentiate functional studies of the complex as well as crystallographic studies of drug binding and provide structural insight into a third class of the <I>bc</I> complex superfamily.</P></▼2>