879 research outputs found
Phylogenetic analysis of human Tp53 gene using computational approach
The TP53 gene encoding p53 protein is involved in regulating a series of pathways. New discoveries about the function and control of p53 are still in progress and it is hoped to develop better therapeutics and diagnostics by exploiting this system. Evolutionary studies are of prime importance in the field of biological research since very long as provide the basis for comparative genomics. The sequence of Homo sapiens human TP53, transcript variant-1 mRNA sequence was retrieved from the NCBI in FASTAformat and was studied for its relationships and percent similarity within human and others species. Genetic variation among TP53 found in human beings and other organisms were studied in detail. Multiple sequence alignment and phylogenetic analysis of the human TP53, transcript variant-1 mRNA sequence through UPGMA was performed which showed its relationship and pattern of variations among different organisms. This study will help in modern research strategies through the manipulation of p53 as its pathways are emerging rapidly and one can predict its extensive clinical use in the near future for the human benefit worldwide.Key words: P53, tumour, cancer, phylogeny, sequence alignment
Effect of explant plant source and acetosyringone concentration on transformation efficiency of wheat cultivars
Gene introduction into crop plants through genetic manipulation is a better alternative to conventional breeding for the improvement of stress tolerance. Agrobacterium-mediated transformation offers precise integration of genes into the genome with enhanced transgene stability. There are a number of factors which influence the rate of genetic transformation. The theme of this study is to exploit the explant source and acetosyringone concentration for the efficient development of Agrobacterium-mediated gene delivery system in wheat cultivars Inqilab 91 and Chakwal 97. Seedlings, mature embryos and calli used as explant sources for transformation in both the cultivars showed positive response. It was further observed that mature embryos produced maximum transformation efficiencies of 40.0 and 36.25% with 37.5 and 31.03% of regeneration frequencies of transgenic plants for Chakwal 97 and Inqilab 91, respectively. Seedlings produced 33.75 and 27.5% while calli produced 26.25 and 22.5% transformation efficiencies for both the cultivars. Acetosyringone concentration is also a limiting factor in transformation experiments especially in the case of cereals crop. Different concentrations of acetosyringone were used at the time of co-cultivation for optimization of the transformation protocol and maximum transformation efficiencies of 52.44 and 47.56% were obtained with 50 μM of acetosyringone from the cultivars Chakwal 97 and Inqilab 91, respectively.Key words: Wheat, agrobacterium, transformation, explant, acetosyringone
miRNAs: Small but deadly
microRNAs (miRNAs) are unique class of global gene regulators identified both in plants and animals. They can reduce protein levels of their target genes with a minor impact on the target genes mRNA. Levels of some miRNAs are found altered in cancers, so we might expect these regulatory molecules to be involved in the development of different carcinomas. The differential expression of certain miRNAs in various tumors might become a powerful tool to aid in the diagnosis and treatment of cancers. The precise biological roles of most miRNAs are still poorly understood and therefore, this review is an attempt to highlight the role and connections of human miRNA with different aspects of cancers.Key words: microRNA, cancer, tumour, metastasis, upregulation, miRNA
Maternal thyroid function in women undergoing controlled ovarian hyperstimulation during IVF and its relation to reproductive outcome.
A prospective observational study undertaken in 2013 at Medically Assisted Conception unit of UKM Medical Centre. The study was carried out among women scheduled for COH in preparation in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI). A total of 88 were included for final analysis. Serum thyroid levels were measured at 4 points; before stimulation (T1), day 10 –13 of cycle (T2), during oocyte retrieval (T3) and at one week following embryo transfer (T4). Results were analyzed according to reproductive outcome
A novel single-phase shunt active power filter based on a current-source converter with reduced Dc-Link
Nowadays, the majority of electronic equipment behave as nonlinear loads, introducing Power Quality (PQ) problems into the Power Grid (PG), namely, current harmonics and low power factor. These PQ problems contribute to the reduction of the efficiency of the transmission and distribution PG, as well as induce the malfunctioning of sensitive loads connected to the PG. Therefore, the development of equipment able to mitigate these PQ problems is extremely important. In this context, this paper presents a novel single-phase Shunt Active Power Filter (SAPF) based on a current-source converter, where the key differencing factor, when compared with the conventional approach, is the reduced dc-link. As the proposed topology requires a reduced dc-link, it represents a relevant advantage, since a typical current-source converter needs an inductor with a high inductance in dc-link, which results in higher losses, costs and component sizing. The proposed SAPF with reduced dc-link is introduced in detail along the paper and a comprehensive comparison with the conventional SAPF is established based on computer simulations. Besides, an experimental validation was carried-out with a developed laboratory prototype, validating the main advantages of the proposed SAPF with reduced dc-link.This work has been supported by FCT – Fundação para a Ciência e Tecnologia with-in the Project Scope: UID/CEC/00319/2019. This work has been supported by the FCT Project QUALITY4POWER PTDC/EEI-EEE/28813/2017, and by the FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017
Prevalence and predisposing factors for hepatitis C virus in haemodialysis unit Universiti Kebangsaan Malaysia Medical Centre
Design of Lipid-Based Nanocarriers via Cation Modulation of Ethanol-Interdigitated Lipid Membranes
Short-chain alcohols (i.e., ethanol) can induce membrane interdigitation in saturated-chain phosphatidylcholines (PCs). In this process, alcohol molecules intercalate between phosphate heads, increasing lateral separation and favoring hydrophobic interactions between opposing acyl chains, which interpenetrate forming an interdigitated phase. Unraveling mechanisms underlying the interactions between ethanol and model lipid membranes has implications for cell biology, biochemistry, and for the formulation of lipid-based nanocarriers. However, investigations of ethanol–lipid membrane systems have been carried out in deionized water, which limits their applicability. Here, using a combination of small- and wide-angle X-ray scattering, small-angle neutron scattering, and all-atom molecular dynamics simulations, we analyzed the effect of varying CaCl2 and NaCl concentrations on ethanol-induced interdigitation. We observed that while ethanol addition leads to the interdigitation of bulk phase 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers in the presence of CaCl2 and NaCl regardless of the salt concentration, the ethanol-induced interdigitation of vesicular DPPC depends on the choice of cation and its concentration. These findings unravel a key role for cations in the ethanol-induced interdigitation of lipid membranes in either bulk phase or vesicular form
Fate of liposomes in presence of phospholipase C and D: from atomic to supramolecular lipid arrangement
Understanding the origins of lipid membrane bilayer rearrangement in response to external stimuli is an essential component of cell biology and the bottom-up design of liposomes for biomedical applications. The enzymes phospholipase C and D (PLC and PLD) both cleave the phosphorus–oxygen bonds of phosphate esters in phosphatidylcholine (PC) lipids. The atomic position of this hydrolysis reaction has huge implications for the stability of PC-containing self-assembled structures, such as the cell wall and lipid-based vesicle drug delivery vectors. While PLC converts PC to diacylglycerol (DAG), the interaction of PC with PLD produces phosphatidic acid (PA). Here we present a combination of small-angle scattering data and all-atom molecular dynamics simulations, providing insights into the effects of atomic-scale reorganization on the supramolecular assembly of PC membrane bilayers upon enzyme-mediated incorporation of DAG or PA. We observed that PC liposomes completely disintegrate in the presence of PLC, as conversion of PC to DAG progresses. At lower concentrations, DAG molecules within fluid PC bilayers form hydrogen bonds with backbone carbonyl oxygens in neighboring PC molecules and burrow into the hydrophobic region. This leads initially to membrane thinning followed by a swelling of the lamellar phase with increased DAG. At higher DAG concentrations, localized membrane tension causes a change in lipid phase from lamellar to the hexagonal and micellar cubic phases. Molecular dynamics simulations show that this destabilization is also caused in part by the decreased ability of DAG-containing PC membranes to coordinate sodium ions. Conversely, PLD-treated PC liposomes remain stable up to extremely high conversions to PA. Here, the negatively charged PA headgroup attracts significant amounts of sodium ions from the bulk solution to the membrane surface, leading to a swelling of the coordinated water layer. These findings are a vital step toward a fundamental understanding of the degradation behavior of PC lipid membranes in the presence of these clinically relevant enzymes, and toward the rational design of diagnostic and drug delivery technologies for phospholipase-dysregulation-based diseases
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