Evidence for the presence of somatic mitochondrial DNA mutations in right atrial appendage tissues of coronary artery disease patients

Coronary artery disease (CAD) is a multifactorial disease with the underlying involvement of environment, life style and nuclear genetics. However, the role of extranuclear genetic material in terms of somatically acquired mutations in mitochondrial tRNA and protein coding genes in the initiation or progression of CAD is not well defined. Hence, in the present study, right atrial appendage tissues and matched blood samples of 150 CAD patients were screened for mutations in nucleotide regions encompassing the Cytochrome c oxidase subunit II (MT-CO2), tRNA lysine (MT-TK), ATP synthase F0 subunit 8 (MT-ATP8) and Cytochrome b (MT-CYB) genes of mitochondrial DNA. We have found 9 different somatic mutations in 6 % of the CAD patients. Out of these mutations, 4 each were localized in MT-TK gene (T8324A, A8326G, A8331G and A8344G) and MT-CYB genes (T15062C, C15238A, T15378G and C15491G) in addition to one mutation in non-coding region 7 (A8270T) of mitochondrial genome. In addition, we noticed that majority (85.3 %) of CAD patients showed double repeats of germ-line “CCCCCTCTA” intergenic sequence between MT-CO2 and MT-TK genes. Our in-silico investigations of missense mutations revealed that they may alter the free energy and stability of polypeptide chains of MT-CYB protein of complex III of mitochondrial respiratory chain. Based on our study findings, we hypothesize that the somatically acquired variations in MT-TK and MT-CYB genes may negatively impact the energy metabolism of cardiomyocytes in right atrial appendage tissues and contribute in the cardiac dysfunction among CAD patients. In conclusion, our findings may be likely to have potential implications in understanding the disease pathophysiology, diagnosis as well as for the better therapeutic management of CAD patients.     

Mathematical model that predicts lower leg motion in response to electrical stimulation

Electrical stimulation of skeletal muscles of patients with upper motor neuron lesions can be used to restore functional movements such as standing or walking. Mathematical muscle models can assist in designing stimulation patterns that will enable patients to perform particular tasks more efficiently. In this study we extend our previous model to allow us to predict changes in knee joint angle in response to electrical stimulation of the human quadriceps femoris muscle. The model was tested both with and without inertial loads placed around the ankle joints of healthy subjects. Results showed that the model predicted the knee extensions with a RMS angle error that was generally 相似文献   

Agrobacterium and biolistic transformation of onion using non-antibiotic selection marker phosphomannose isomerase

A new selection system for onion transformation that does not require the use of antibiotics or herbicides was developed. The selection system used the Escherichia coli gene that encodes phosphomannose isomerase (pmi). Transgenic plants carrying the manA gene that codes for pmi can detoxify mannose-6-phosphate by conversion to fructose-6-phosphate, an intermediate of glycolysis, via the pmi activity. Six-week-old embryogenic callus initiated from seedling radicle was used for transformation. Transgenic plants were produced efficiently with transformation rates of 27 and 23% using Agrobacterium and biolistic system, respectively. Untransformed shoots were eliminated by a stepwise increase from 10 g l⁻¹ sucrose with 10 g l⁻¹ mannose in the first selection to only10 g l⁻¹ mannose in the second selection. Integrative transformation was confirmed by PCR, RT-PCR and Southern hybridization. An erratum to this article can be found at     

Spectral and kinetic characterization of 7,8-diaminopelargonic acid synthase from Mycobacterium tuberculosis

The indispensability of biotin for crucial processes like lipid biosynthesis coupled to the absence of the biotin biosynthesis pathway in humans make the enzymes of this pathway, attractive targets for development of novel drugs against numerous pathogens including M. tuberculosis. We report the spectral and kinetic characterization of the Mycobacterium tuberculosis 7,8-Diaminopelargonic acid (DAPA) synthase, the second enzyme of the biotin biosynthesis pathway. In contrast to the E. coli enzyme, no quinonoid intermediate was detected during the steady state reaction between the enzyme and S-adenosyl-L-methionine (SAM). The second order rate constant for this half of the reaction was determined to be 1.75 +/- 0.11 M-1s-1. The Km values for 7-keto-8-aminopelargonic acid (KAPA) and SAM are 2.83 microM and 308.28 microM, respectively whereas the Vmax and kcat values for the enzyme are 0.02074 micromoles/min/ml and 0.003 s-1, respectively. Our initial studies pave the way for further detailed mechanistic and kinetic characterization of the enzyme.     

Cloning, expression, and purification of a novel recombinant antigen from Leishmania donovani

Visceral leishmaniasis (VL) is a major health problem in the tropical and subtropical regions of the world. The conventional methods for diagnosis of Old World Visceral leishmaniasis are difficult, insensitive, and hazardous. There is no recombinant antigen from old world Leishmania species which can be commercially used for rapid diagnosis. There is an urgent need for a less invasive and accurate method. Here, we report a recombinant antigen from Indian Leishmania donovani for its diagnosis. The kinesin gene of a L. donovani clinical isolate (KE16) from India was PCR amplified for cloning and the immunodominant domain was expressed in Escherichia coli. This recombinant protein or Ld-rKE16 was evaluated for serodiagnosis of Indian kala-azar by ELISA. The recombinant antigen was found to be 100% sensitive and specific for Old World VL cases from India, Pakistan, China, and Turkey. The antigen showed no cross-reactivity with sera from other endemic diseases or healthy controls. The expressed Ld-rKE16 antigen is highly specific and sensitive for diagnosing visceral and post-kala-azar dermal leishmaniasis and is ready for commercialization.     

Synthesis of peptidyl ureas employing O-succinimidyl-(9H-fluoren-9-ylmethoxycarbonylamino) methylcarbamate derivatives as activated monomers

A convenient and efficient method for the synthesis of dipeptidyl ureas and urea acids employing O-succinimidyl-(9H-fluoren-9-ylmethoxycarbonyl amino)methylcarbamates has been described. All the compounds, obtained in good yields, have been fully characterized by mass and NMR spectra.     

Design and synthesis of novel HIV-1 protease inhibitors incorporating oxyindoles as the P2'-ligands

A series of novel oxyindole-derived HIV-1 protease inhibitors were designed and synthesized based upon our X-ray crystal structure of inhibitor 2 (TMC-114) bound to HIV-1 protease. The effects of substituents, spirocyclic rings, and ring sizes have been investigated. A number of inhibitors exhibited low nanomolar inhibitory potencies against HIV protease.     

Separation of actinides and lanthanides: Synthesis and molecular structure of a new di-μ-phenoxo-bridged dinuclear bis(dioxouranium(VI)) complex

The new phenoxo-bridged uranyl [(UO₂)₂L₂(thf)₂] [H₂L = N(2-oxyphenyl)-3-methoxy salicylaldiminato (C₁₄H₁₁NO₃)] compound has been synthesized and characterized. The 3D structure of the free ligand is also reported. The complex crystallizes in the monoclinic space group P2₁/c with lattice parameters a = 19.5915(15) Å, b = 10.4096(9) Å, c = 17.5216(14) Å and β = 99.9960(7)° with z = 4. The compound consists of a dinuclear unit composed of two dioxouranium(VI) ions, bridged by two phenoxide oxygens. The coordination around each uranium atom can be regarded as approximately pentagonal bipyramidal. The two uranyl groups are separated by 3.9192(5) Å. The title complex is one of the few examples for bis-uranyl groups bridged by phenoxo ligands. These types of ligands are candidates for the sequestration of the uranium from nuclear waste and provide a good selectivity over competing lanthanide cations in solution. The ligand has been found to selectively bind to a representative actinide rather than to lanthanum (Ln³⁺), which is probably related to the larger ionic radii of Ln(III). So, the ligand is not suitable to clutch two lanthanide metals via the phenolate bridge (Ln-O_(phenol)-Ln). The spherical shape and the larger size of the Ln(III) ions apparently do not allow a fit within the byte angle of phenolate bridge.     

Acylated 5,7,2',6'-oxygenated flavone glycosides from Andrographis alata

Five acylated 5,7,2',6'-oxygenated flavone glycosides along with the known 5,2',6'-trihydroxy-7-methoxyflavone-2'-O-beta-d-glucopyranoside have been isolated from the whole plant of Andrographis alata. The structures of the compounds were established from spectral (mainly 1D and 2D NMR) and chemical studies.