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The Paradoxical Effect of Paraquat on Leucyl-tRNA Levels in <i>E. coli</i>Provides New Insights for Amino Acid Therapy in Humans

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CellBio 2018年第4期7卷 51-62页

作者： babu v. Bassa Olen R. Brown John M. Dalton Cardiovascular Research Center University of Missouri Columbia MO USA

Dihydroxyacid dehydratase (DHAD), the rate-limiting enzyme in the synthesis of branched-chain (BCA) amino acids in bacteria and plants, is sensitive to oxyradical toxicity. Oxidant stress reversibly inactivates DHAD and causes starvation for BCA and reversible cessation of growth in Escherichia coli [1][2]. To better understand the underlying toxicity mechanisms, we have determined the cellular concentrations of charged-tRNAs for BCA, in E. coli treated with the redox-active chemical, paraquat. Contrary to expectation, in the paraquat-treated cells, the concentration of only charged leucyl-tRNA decreased dramatically;whereas, the concentrations of the other BCAs (valine and isoleucine) increased. This paradoxical result, the “paraquat effect” can be best explained if leucine is the most abundant amino acid in the E. coli proteins and therefore the rate-limiting building block in their synthesis. Based on this assumption, we investigated the concentration of free amino acids in E. coli and their relative abundances in E. coli proteins. Protein amino acid frequencies were determined by analyzing one-hundred gene bank protein sequences with software developed as described in Methods. Leucine is the most abundant amino acid in the E. coli proteins (10%) and consequently, the cellular free leucine concentration is smaller and the native charged-leucyl-tRNA levels are much higher than those of valine and isoleucine. This has relevance to humans because: leucine-deprivation was shown to be beneficial in tumor suppression [3], and leucine-supplementation was beneficial in the recovery from exercise-induced muscle loss [4][5], and leucine also occurs at a higher frequency in almost all human proteins. In three human protein categories, we examined it ranged from 9% to 17%. This predominance of leucine in proteins would make cells vulnerable to impairment of the leucine pools and could explain our results in E. coli and some of the biological effects of free leucine in humans

关键词： E. coli Leucine Leucyl-tRNA Paraquat Leucine Abundance Amino Acid Starvation Cancer Therapy

Evaluation of genetic potential of the polyvoltine silkworm (Bombyx mori L.) germplasm and identification of parents for breeding programme

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2006年第3期7卷 215-220页

作者： RAO C.G.P. SESHAGIRI S.v. ramesh C. IBRAHIM BASHA K. NAGARAJU H. CHANDRASHEKARAIAH Andhra Pradesh State Sericulture Research and Development Institute (APSSRDI) Kirikera Hindupur-515 211 India

In the present study, polyvoltine germplasm stock ofAndhra Pradesh State Sericulture Research and Development, Institute （APSSRDI） was evaluated for its performance based on quantitative and qualitative traits. Twenty-one oval and 10 peanut cocoon shaped lines were reared in different seasons of the year. Since the polyvoltines are non-diapausing, six generations were reared and evaluated for various economically important traits based on evaluation index and sub-ordinate function statistical methods. Ten top ranked lines obtained by using both the methods were identified as potential parental strains. Among oval lines, APMI4, APMI 1, APMIS, APMW9, and APMI9, and among peanut lines APMD5, APMDI, APMD3, APMD9 and APMD8 were selected as base material. The identified high yielding lines will be used in various breeding programmes as initial parents for the synthesis of superior polyvoltine breeds/hybrids.

关键词： Polyvoltine Silkworm Germplasm Performance Evaluation

In silico prediction of monovalent and chimeric tetravalent vaccines for prevention and treatment of dengue fever

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The Journal of Biomedical Research 2018年第3期32卷 222-236页

作者： vijayakumar Subramaniyan ramesh venkatachalam Prabhu Srinivasan Manogar Palani Computational Phytochemistry Laboratory P.G. and Research Department of Botany and Microbiology A.V.V.M. Sri Pushpam College (Autonomous)

Reverse vaccinology method was used to predict the monovalent peptide vaccine candidate to produce antibodies for therapeutic purpose and to predict tetravalent vaccine candidate to act as a common vaccine to cover all the dengue virus serotypes. Envelope（E）-proteins of DENv-1-4 serotypes were used for vaccine prediction using NCBI,Uniprot/Swissprot, Swiss-prot viewer, vaxiJen v2.0, TMHMM, BCPREDS, Propred-1, Propred and MHC Pred. Eproteins of DENv-1-4 serotypes were identified as antigen from which T cell epitopes, through B cell epitopes, were predicted to act as peptide vaccine candidates. Each selected T cell epitope of E-protein was confirmed to act as vaccine and to induce complementary antibody against particular serotype of dengue virus. Chimeric tetravalent vaccine was formed by the conjugation of four vaccines, each from four dengue serotypes to act as a common vaccine candidate for all the four dengue serotypes. It can be justifiably concluded that the monovalent 9-mer T cell epitope for each DENv serotype can be used to produce specific antibody against dengue virus and a chimeric common tetravalent vaccine candidate to yield a comparative vaccine to cover any of the four dengue virus serotype. This vaccine is expected to be highly immunogenic against dengue fever.

关键词： dengue serotypes dengue virus vaccine E-proteins MHC Ⅰ and Ⅱ

Use of Teriparatide to improve fracture healing: What is the evidence?

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World Journal of Orthopedics 2015年第6期6卷 457-461页

作者： Satish babu Nemandra A Sandiford Mark vrahas Core Surgical Trainee St. George’s Hospital Lower Limb and Tumor Reconstruction Fellow University of British Columbia Orthopaedic Trauma Service Massachusetts General Hospital

Teriparatide is a recombinant form of the biologicallyactive component of Parathyroid hormone. It has been shown to increase bone mass and prevent fractures in osteoporotic bone. It is licensed by the Food and Drug Administration for the treatment of Osteoporosis. Over the last decade, a growing body of evidence has accumulated suggesting a role for Teriparatide in the management of fractures. Studies in both normal and delayed healing models have shown improvement in callus volume and mineralisation, bone mineral content, rate of successful union and strength at fracture sites. However most of these results have been derived from animal studies. The majority of this research on humans has comprised low level evidence, with few randomised controlled trials, many case reports and case series. Nevertheless, the results from these studies seem to support research from animal models. This has led to a growing number of clinicians using Teriparatide "off license" to treat fractures and non-unions in their patients. This review presents a critical appraisal of the current evidence supporting the use of Teriparatide for fracture healing, delayed unions and non unions and in the setting of osteoporotic fractures, the studies producing this evidence and their transferability to human beings.

关键词： Teriparatide Fractures Healing Bone Osteoporosis

Origins of the long-range exciton diffusion in perovskite nanocrystal films: photon recycling vs exciton hopping

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Light(Science & Applications) 2021年第1期10卷 41-49页

作者： David Giovanni Marcello Righetto Qiannan Zhang Jia Wei Melvin Lim Sankaran ramesh Tze Chien Sum Division of Physics and Applied Physics School of Physical and Mathematical SciencesNanyang Technological University(NTU)21 Nanyang LinkSingapore 637371Singapore Energy Research Institute@NTU(ERI@N) Interdisciplinary Graduate SchoolNanyang Technological University50 Nanyang AvenueS2-B3a-01Singapore 639798Singapore

The outstanding optoelectronic performance of lead halide perovskites lies in their exceptional carrier diffusion *** the perovskite material dimensionality is reduced to exploit the quantum confinement effects,the disruption to the perovskite lattice,often with insulating organic ligands,raises new questions on the charge diffusion ***,we report direct imaging of>1μm exciton diffusion lengths in CH3NH3PbBr3 perovskite nanocrystal(PNC)***,the resulting exciton mobilities in these PNC films can reach 10±2cm^(2)v^(-1) s^(-1),,which is counterintuitively several times higher than the carrier mobility in 3D perovskite *** show that this ultralong exciton diffusion originates from both efficient inter-NC exciton hopping(via Forster energy transfer)and the photon recycling process with a smaller yet significant ***,our study not only sheds new light on the highly debated origins of the excellent exciton diffusion in PNC films but also highlights the potential of PNCs for optoelearonic applications.

关键词： properties. perovskite diffusion

Role of tissue microenvironment resident adipocytes in colon cancer

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World Journal of Gastroenterology 2017年第32期23卷 5829-5835页

作者： Maria Tabuso Shervanthi Homer-vanniasinkam Raghu Adya ramesh P Arasaradnam Department of Gastro-enterology University Hospitals Coventry and Warwickshire Warwick Medical School University of Warwick Leeds Institute of Car-diovascular and Metabolic Medicine Faulty of Medicine and HealthUniversity of Leeds Division of Surgical and Interventional Sciences UCL Medical School Building Applied Biological and Experimental Sciences University of Coventry

Colorectal cancer(CRC) is a multifactorial disease characterized by several genetic and epigenetic alterations occurring in epithelial cells. It is increasingly recognized that tumour progression is also regulated by tumour microenvironment(TME). The bidirectional cross-talk between tumour resident adipocytes and cancer cells within TME has been proposed as active contributor to carcinogenesis. Tumour resident adipocytes exhibit an activated phenotype characterized by increased secretion of pro-tumorigenic factors(angiogenic/inflammatory/immune) which contribute to cancer cell proliferation, invasion, neoangiogenesis, evasion of immune surveillance and therapy resistance. Furthermore, adipocytes represent a fuel rich source for increasing energy demand of rapidly proliferating tumour cells. Interestingly, a relationship between obesity and molecular variants in CRC has recently been identified. Whether adipose tissue promotes cancer progression in subsets of molecular phenotypes or whether local tissue adipocytes are involved in inactivation of tumour suppressor genes and/or activation of oncogenes still needs to be explored. This editorial highlights the major findings related to crosstalk between adipocytes and colon cancer cells and how local paracrine interactions may promote cancer progression. Furthermore, we provide future strategies in studying colonic TME which could provide insights in bidirectional cross-talk mechanisms between adipocytes and colonic epithelial cells. This could enable to decipher critical signalling pathways of both early colonic carcinogenesis and cancer progression.

关键词： Tumour resident adipocytes Dysfunctional adipocytes Adipose tissue Cancer cell-tumour resident adipocyte cross-talk Colon cancer microenvironment

Exploring the electromagnetic shielding behavior of lanthanum doped calcium nanoferrites

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Journal of Rare Earths 2024年第11期42卷 2128-2136,I0005页

作者： E.Ahilandeswari K.Sakthipandi R.Rajesh Kanna G.Rajkumar B.Ganesh babu S.Arunmetha Aslam Hossain P.Sakthivel v.Rajendran M.Srinidhi Raghavan Department of Physics SRM TRP Engineering CollegeTiruchirappalli621105Tamil NaduIndia Department of Electronics and Communication Engineering M.Kumarasamy College of EngineeringKarur639113Tamil NaduIndia Department of Physics Easwari Engineering CollegeChennai600089Tamil NaduIndia Department of Mechanical Engineering SRM TRP Engineering CollegeTiruchirappalli621105Tamil NaduIndia Centre for Advanced Energy Studies Department of Electronics and Communication EngineeringKoneru Lakshmaiah Education FoundationGunturAndhra Pradesh522502India Smart Materials Research Institute Southern Federal UniversitySladkova 178/24344090Rostov-on-DonRussia Centre for Materials Science Department of PhysicsScience and HumanitiesFaculty of EngineeringKarpagam Academy of Higher EducationCoimbatore641021Tamil NaduIndia Centre for Nanotechnology Academy of Maritime Education and Training(Deemed to be University)Chennai603112Tamil NaduIndia Department of Chemistry and Centre for Nano-Materials and Displays B.M.S.College of EngineeringBengaluru560019KarnatakaIndia

The present study focuses on the synthesis and characterization of lanthanum(La^(3+))-doped calcium nanoferrites(CaLa_(x)Fe_(2-x)O_(4):x=0.025,0.050,0.075 and 0.100)using the sonochemical *** techniques were employed to analyze the effect of La^(3+)infusion,Raman spectroscopy confirms the presence of active A_(1g),T_(2g)and E_g modes in the CaLa_(x)Fe_(2-x)O_(4)nanoferrite,indicating the formation of an active ferrite *** introduction of La^(3+)doping results in a significant increase in the band gap energy,rendering the nanoferrites insulating(3.23-3,57 ev).At higher frequencies,the impedance studies reveal minimal losses and better AC conductivity,pointing to improved dielectric *** higher frequencies,the Q-factor of La-doped calcium nanoferrites shows lower electromagnetic *** M-H curve exhibits ferromagnetic behavior,with La^(3+)-doped calcium nano ferrites displaying a saturation magnetization ranging from 12.72 to 18.10 emu/*** incorporation of La^(3+)also induces enhanced electrical polarization,leading to notable dielectric loss and increased absorption of electromagnetic ***,these CaLa_(x)Fe_(2-x)O_(4)nanoferrites demonstrate potential as effective microwave absorbers across a wide frequency range,with significant shielding absorption observed at 8.8-9.1 GHz.

关键词： Nanoferrites Structural properties Rare earths Dielectric Magnetism Microwave absorption

Numerical study on thermal therapy of triple layer skin tissue using fractional bioheat model

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International Journal of Biomathematics 2018年第4期11卷 125-148页

作者： Sushil Kumar ramesh S. Damor Ajay K. Shukla Department of Applied Mathematics & Humanities S. v. National Institute of Technology Surat Gujarat 395007 India L. E. College Sama Kanthe Morbi Gujarat 363642 India Department of Applied Mathematics & Humanities S. v. National Institute of Technology Snrat Gujarat 395007 India

This paper deals with the study of heat transfer and thermal damage in triple layer skin tissue using fractional bioheat model. Here, we consider three types of heating viz. sinusoidal heat flux, constant temperature and constant heat flux heating on skin surface. An implicit finite difference scheme is obtained by approximating fractional time derivative by quadrature formula and space derivative by central difference formula. The temperature profiles and thermal damage in the skin tissue are obtained to study the effect of fractional parameter a on diffusion process for constant temperature and heat flux boundary heating on skin surface. A parametric study for sinusoidal heat flux at skin surface has also been made.

关键词： Bioheat transfer fractional calculus finite difference method triple layerskin thermal damage Caputo derivative.

Network Connectivity Probability of Linear vehicular Ad Hoc Networks on Two-Way Street

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Communications and Network 2012年第4期4卷 332-341页

作者： P. C. Neelakantan A. v. babu Department of Electronics and Communication Engineering National Institute of Technology Calicut India

In this paper, we present an analytical model to determine the network connectivity probability of a linear vehicular ad hoc network (vANET) formed by communication equipped vehicles on a two-way street scenario. We consider the highway to be consisting of two lanes with vehicles moving in both directions on these lanes and focus on the probability of being able to convey messages from a source vehicle to a destination vehicle, which may be multiple hops away. Closed form analytical expression is obtained for the network connectivity probability in the presence of Nakagami fading channel. In our model, the transmission range of each vehicle is modeled as a random variable due to channel fading. The analytical results are validated by extensive simulations.

关键词： Two-Way Connectivity Nakagami Fading vehicular Ad Hoc Network Twocolumnfalse