Molecular pathogenesis and mechanisms of thyroid cancer

Science.gov (United States)

Xing, Mingzhao

2013-01-01

Thyroid cancer is a common endocrine malignancy. There has been exciting progress in understanding its molecular pathogenesis in recent years, as best exemplified by the elucidation of the fundamental role of several major signalling pathways and related molecular derangements. Central to these mechanisms are the genetic and epigenetic alterations in these pathways, such as mutation, gene copy-number gain and aberrant gene methylation. Many of these molecular alterations represent novel diagnostic and prognostic molecular markers and therapeutic targets for thyroid cancer, which provide unprecedented opportunities for further research and clinical development of novel treatment strategies for this cancer. PMID:23429735

Origin of microbial life: Nano- and molecular events, thermodynamics/entropy, quantum mechanisms and genetic instructions.

Science.gov (United States)

Trevors, J T

2011-03-01

Currently, there are no agreed upon mechanisms and supporting evidence for the origin of the first microbial cells on the Earth. However, some hypotheses have been proposed with minimal supporting evidence and experimentation/observations. The approach taken in this article is that life originated at the nano- and molecular levels of biological organization, using quantum mechanic principles that became manifested as classical microbial cell(s), allowing the origin of microbial life on the Earth with a core or minimal, organic, genetic code containing the correct instructions for cell(s) for growth and division, in a micron dimension environment, with a local entropy range conducive to life (present about 4 billion years ago), and obeying the laws of thermodynamics. An integrated approach that explores all encompassing factors necessary for the origin of life, may bring forth plausible hypotheses (and mechanisms) with much needed supporting experimentation and observations for an origin of life theory. Copyright © 2010 Elsevier B.V. All rights reserved.

Molecular Genetics of Beauveria bassiana Infection of Insects.

Science.gov (United States)

Ortiz-Urquiza, A; Keyhani, N O

2016-01-01

Research on the insect pathogenic filamentous fungus, Beauveria bassiana has witnessed significant growth in recent years from mainly physiological studies related to its insect biological control potential, to addressing fundamental questions regarding the underlying molecular mechanisms of fungal development and virulence. This has been in part due to a confluence of robust genetic tools and genomic resources for the fungus, and recognition of expanded ecological interactions with which the fungus engages. Beauveria bassiana is a broad host range insect pathogen that has the ability to form intimate symbiotic relationships with plants. Indeed, there is an increasing realization that the latter may be the predominant environmental interaction in which the fungus participates, and that insect parasitism may be an opportunist lifestyle evolved due to the carbon- and nitrogen-rich resources present in insect bodies. Here, we will review progress on the molecular genetics of B. bassiana, which has largely been directed toward identifying genetic pathways involved in stress response and virulence assumed to have practical applications in improving the insect control potential of the fungus. Important strides have also been made in understanding aspects of B. bassiana development. Finally, although increasingly apparent in a number of studies, there is a need for progressing beyond phenotypic mutant characterization to sufficiently investigate the molecular mechanisms underlying B. bassiana's unique and diverse lifestyles as saprophyte, insect pathogen, and plant mutualist. Copyright © 2016 Elsevier Inc. All rights reserved.

Additional mechanisms conferring genetic susceptibility to Alzheimer's disease

Directory of Open Access Journals (Sweden)

Miguel eCalero

2015-04-01

Full Text Available Familial Alzheimer's disease (AD, mostly associated with early onset, is caused by mutations in three genes (APP, PSEN1 and PSEN2 involved in the production of the amyloid  peptide. In contrast, the molecular mechanisms that trigger the most common late onset sporadic AD remain largely unknown. With the implementation of an increasing number of case-control studies and the upcoming of large-scale genome-wide association studies (GWAS there is a mounting list of genetic risk factors associated to common genetic variants that have been associated to sporadic AD. Besides APOE, that presents a strong association with the disease (OR~4, the rest of these genes have moderate or low degrees of association, with OR ranging from 0.88 to 1.23. Taking together, these genes may account only for a fraction of the attributable AD risk and therefore, rare variants and epistastic gene interactions should be taken into account in order to get the full picture of the genetic risks associated to AD. Here, we review recent whole-exome studies looking for rare variants, somatic brain mutations with a strong association to the disease, and several studies dealing with epistasis as additional mechanisms conferring genetic susceptibility to AD. Altogether, recent evidence underlines the importance of defining molecular and genetic pathways and networks rather than the contribution of specific genes.

Teaching molecular genetics: Chapter 1--Background principles and methods of molecular biology.

NARCIS (Netherlands)

Knoers, N.V.A.M.; Monnens, L.A.H.

2006-01-01

In this first chapter of the series "Teaching molecular genetics," an introduction to molecular genetics is presented. We describe the structure of DNA and genes and explain in detail the central dogma of molecular biology, that is, the flow of genetic information from DNA via RNA to polypeptide

Introduction to Genetic Mechanisms of Carcinogenesis

International Nuclear Information System (INIS)

Yang, W.K.

1983-01-01

Recent technical advances in nucleic acid research and molecular biology have made it possible to explore the complicated genetic systems of eukaryotic cells. One of the fields showing rapid progress concerns genes and gene regulatory functions related to neoplastic processes. Thus, the 35th Annual Conference of the Biology Division of Oak Ridge National Laboratory, held at Gatlinburg, April 12-15, 1982, was organized with the intention to bring together investigators working on seemingly diverse fields of cancer research to discuss and exchange their views on the genetic mechanisms of carcinogenesis. The meeting was attended by workers from chemical, physical as well as biological carcinogenesis fields, by classical geneticists as well as by molecular biologists, and by researchers interested in experimental as well as in human cancers. Included in this volume are papers by the invited speakers of the symposium as well as by those presenting poster papers at the meeting

Molecular Mechanism and Genetic Determinants of Buprofezin Degradation

OpenAIRE

Chen, Xueting; Ji, Junbin; Zhao, Leizhen; Qiu, Jiguo; Dai, Chen; Wang, Weiwu; He, Jian; Jiang, Jiandong; Hong, Qing; Yan, Xin

2017-01-01

Buprofezin is a widely used insect growth regulator whose residue has been frequently detected in the environment, posing a threat to aquatic organisms and nontarget insects. Microorganisms play an important role in the degradation of buprofezin in the natural environment. However, the relevant catabolic pathway has not been fully characterized, and the molecular mechanism of catabolism is still completely unknown. Rhodococcus qingshengii YL-1 can utilize buprofezin as a sole source of carbon...

Physiological, Molecular and Genetic Mechanisms of Long-Term Habituation

Energy Technology Data Exchange (ETDEWEB)

Calin-Jageman, Robert J

2009-09-12

Work funded on this grant has explored the mechanisms of long-term habituation, a ubiquitous form of learning that plays a key role in basic cognitive functioning. Specifically, behavioral, physiological, and molecular mechanisms of habituation have been explored using a simple model system, the tail-elicited siphon-withdrawal reflex (T-SWR) in the marine mollusk Aplysia californica. Substantial progress has been made on the first and third aims, providing some fundamental insights into the mechanisms by which memories are stored. We have characterized the physiological correlates of short- and long-term habituation. We found that short-term habituation is accompanied by a robust sensory adaptation, whereas long-term habituation is accompanied by alterations in sensory and interneuron synaptic efficacy. Thus, our data indicates memories can be shifted between different sites in a neural network as they are consolidated from short to long term. At the molecular level, we have accomplished microarray analysis comparing gene expression in both habituated and control ganglia. We have identified a network of putatively regulated transcripts that seems particularly targeted towards synaptic changes (e.g. SNAP25, calmodulin) . We are now beginning additional work to confirm regulation of these transcripts and build a more detailed understanding of the cascade of molecular events leading to the permanent storage of long-term memories. On the third aim, we have fostered a nascent neuroscience program via a variety of successful initiatives. We have funded over 11 undergraduate neuroscience scholars, several of whom have been recognized at national and regional levels for their research. We have also conducted a pioneering summer research program for community college students which is helping enhance access of underrepresented groups to life science careers. Despite minimal progress on the second aim, this project has provided a) novel insight into the network mechanisms by

Hyperinsulinemic Hypoglycemia ? The Molecular Mechanisms

OpenAIRE

Nessa, Azizun; Rahman, Sofia A.; Hussain, Khalid

2016-01-01

Under normal physiological conditions, pancreatic β-cells secrete insulin to maintain fasting blood glucose levels in the range 3.5–5.5 mmol/L. In hyperinsulinemic hypoglycemia (HH), this precise regulation of insulin secretion is perturbed so that insulin continues to be secreted in the presence of hypoglycemia. HH may be due to genetic causes (congenital) or secondary to certain risk factors. The molecular mechanisms leading to HH involve defects in the key genes regulating insulin secretio...

Molecular genetic studies on obligate anaerobic bacteria

International Nuclear Information System (INIS)

Woods, D.R.

1982-01-01

Molecular genetic studies on obligate anaerobic bacteria have lagged behind similar studies in aerobes. However, the current interest in biotechnology, the involvement of anaerobes in disease and the emergence of antibioticresistant strains have focused attention on the genetics of anaerobes. This article reviews molecular genetic studies in Bacteroides spp., Clostridium spp. and methanogens. Certain genetic systems in some anaerobes differ from those in aerobes and illustrate the genetic diversity among bacteria

Teaching molecular genetics: Chapter 1--Background principles and methods of molecular biology.

Science.gov (United States)

Knoers, Nine V A M; Monnens, Leo A H

2006-02-01

In this first chapter of the series "Teaching molecular genetics," an introduction to molecular genetics is presented. We describe the structure of DNA and genes and explain in detail the central dogma of molecular biology, that is, the flow of genetic information from DNA via RNA to polypeptide (protein). In addition, several basic and frequently used general molecular tools, such as restriction enzymes, Southern blotting, DNA amplification and sequencing are discussed, in order to lay the foundations for the forthcoming chapters.

Molecular mechanisms of methicillin resistance in Staphylococcus aureus.

Science.gov (United States)

Domínguez, M A; Liñares, J; Martín, R

1997-09-01

Methicillin-resistant Staphylococcus aureus (MRSA) strains are among the most common nosocomial pathogens. The most significant mechanism of resistance to methicillin in this-species is the acquisition of a genetic determinant (mecA gene). However, resistance seems to have a more complex molecular basis, since additional chromosomal material is involved in such resistance. Besides, overproduction of penicillinase and/or alterations in the PBPs can contribute to the formation of resistance phenotypes. Genetic and environmental factors leading to MRSA are reviewed.

Vorinostat induces apoptosis and differentiation in myeloid malignancies: genetic and molecular mechanisms.

Directory of Open Access Journals (Sweden)

Gabriela Silva

Full Text Available BACKGROUND: Aberrant epigenetic patterns are central in the pathogenesis of haematopoietic diseases such as myelodysplastic syndromes (MDS and acute myeloid leukaemia (AML. Vorinostat is a HDACi which has produced responses in these disorders. The purpose of this study was to address the functional effects of vorinostat in leukemic cell lines and primary AML and MDS myeloid cells and to dissect the genetic and molecular mechanisms by which it exerts its action. METHODOLOGY/PRINCIPAL FINDINGS: Functional assays showed vorinostat promoted cell cycle arrest, inhibited growth, and induced apoptosis and differentiation of K562, HL60 and THP-1 and of CD33(+ cells from AML and MDS patients. To explore the genetic mechanism for these effects, we quantified gene expression modulation by vorinostat in these cells. Vorinostat increased expression of genes down-regulated in MDS and/or AML (cFOS, COX2, IER3, p15, RAI3 and suppressed expression of genes over-expressed in these malignancies (AXL, c-MYC, Cyclin D1 and modulated cell cycle and apoptosis genes in a manner which would favor cell cycle arrest, differentiation, and apoptosis of neoplastic cells, consistent with the functional assays. Reporter assays showed transcriptional effect of vorinostat on some of these genes was mediated by proximal promoter elements in GC-rich regions. Vorinostat-modulated expression of some genes was potentiated by mithramycin A, a compound that interferes with SP1 binding to GC-rich DNA sequences, and siRNA-mediated SP1 reduction. ChIP assays revealed vorinostat inhibited DNA binding of SP1 to the proximal promoter regions of these genes. These results suggest vorinostat transcriptional action in some genes is regulated by proximal promoter GC-rich DNA sequences and by SP1. CONCLUSION: This study sheds light on the effects of vorinostat in AML and MDS and supports the implementation of clinical trials to explore the use of vorinostat in the treatment of these diseases.

Vorinostat induces apoptosis and differentiation in myeloid malignancies: genetic and molecular mechanisms.

Science.gov (United States)

Silva, Gabriela; Cardoso, Bruno A; Belo, Hélio; Almeida, António Medina

2013-01-01

Aberrant epigenetic patterns are central in the pathogenesis of haematopoietic diseases such as myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML). Vorinostat is a HDACi which has produced responses in these disorders. The purpose of this study was to address the functional effects of vorinostat in leukemic cell lines and primary AML and MDS myeloid cells and to dissect the genetic and molecular mechanisms by which it exerts its action. Functional assays showed vorinostat promoted cell cycle arrest, inhibited growth, and induced apoptosis and differentiation of K562, HL60 and THP-1 and of CD33(+) cells from AML and MDS patients. To explore the genetic mechanism for these effects, we quantified gene expression modulation by vorinostat in these cells. Vorinostat increased expression of genes down-regulated in MDS and/or AML (cFOS, COX2, IER3, p15, RAI3) and suppressed expression of genes over-expressed in these malignancies (AXL, c-MYC, Cyclin D1) and modulated cell cycle and apoptosis genes in a manner which would favor cell cycle arrest, differentiation, and apoptosis of neoplastic cells, consistent with the functional assays. Reporter assays showed transcriptional effect of vorinostat on some of these genes was mediated by proximal promoter elements in GC-rich regions. Vorinostat-modulated expression of some genes was potentiated by mithramycin A, a compound that interferes with SP1 binding to GC-rich DNA sequences, and siRNA-mediated SP1 reduction. ChIP assays revealed vorinostat inhibited DNA binding of SP1 to the proximal promoter regions of these genes. These results suggest vorinostat transcriptional action in some genes is regulated by proximal promoter GC-rich DNA sequences and by SP1. This study sheds light on the effects of vorinostat in AML and MDS and supports the implementation of clinical trials to explore the use of vorinostat in the treatment of these diseases.

Genetic characterization, species differentiation and detection of Fasciola spp. by molecular approaches.

Science.gov (United States)

Ai, Lin; Chen, Mu-Xin; Alasaad, Samer; Elsheikha, Hany M; Li, Juan; Li, Hai-Long; Lin, Rui-Qing; Zou, Feng-Cai; Zhu, Xing-Quan; Chen, Jia-Xu

2011-06-10

Liver flukes belonging to the genus Fasciola are among the causes of foodborne diseases of parasitic etiology. These parasites cause significant public health problems and substantial economic losses to the livestock industry. Therefore, it is important to definitively characterize the Fasciola species. Current phenotypic techniques fail to reflect the full extent of the diversity of Fasciola spp. In this respect, the use of molecular techniques to identify and differentiate Fasciola spp. offer considerable advantages. The advent of a variety of molecular genetic techniques also provides a powerful method to elucidate many aspects of Fasciola biology, epidemiology, and genetics. However, the discriminatory power of these molecular methods varies, as does the speed and ease of performance and cost. There is a need for the development of new methods to identify the mechanisms underpinning the origin and maintenance of genetic variation within and among Fasciola populations. The increasing application of the current and new methods will yield a much improved understanding of Fasciola epidemiology and evolution as well as more effective means of parasite control. Herein, we provide an overview of the molecular techniques that are being used for the genetic characterization, detection and genotyping of Fasciola spp..

Molecular genetic studies of bacteroides fragilis

International Nuclear Information System (INIS)

Southern, J.A.

1986-03-01

This study aimed at providing a means for probing the molecular genetic organization of B.fragilis, particularly those strains where the DNA repair mechanisms had been described. The following routes of investigation were followed: the bacteriocin of B.fragilis BF-1; the investigation of any plasmids which might be discovered, with the aim of constructing a hybrid plasmid which might replicate in both E.coli and B.fragilis; and the preparation of a genetic library which could be screened for Bacteroides genes which might function in E.coli. Should any genes be isolated by screening the library they were to be studied with regard to their expression and regulation in E.coli. The above assays make use of radioactive markers such as 14 C, 35 S, 32 P, and 3 H in the labelling of RNA, plasmids and probes

Molecular genetic researches on the radiation genetics of Drosophila in JINR

International Nuclear Information System (INIS)

Afanas'eva, K.P.; Aleksandrova, M.V.; Aleksandrov, I.D.

2016-01-01

Molecular genetic studies of radiation-induced heritable DNA lesions are carried out by the genetic group of Laboratory of nuclear problem in Joint Institute for Nuclear Research. The first results of molecular analysis of γ –ray- and neutron-induced vestigial mutations using PCR and sequencing will be presented. (authors)

Genetic characterization, species differentiation and detection of Fasciola spp. by molecular approaches

Directory of Open Access Journals (Sweden)

Li Hai-Long

2011-06-01

Full Text Available Abstract Liver flukes belonging to the genus Fasciola are among the causes of foodborne diseases of parasitic etiology. These parasites cause significant public health problems and substantial economic losses to the livestock industry. Therefore, it is important to definitively characterize the Fasciola species. Current phenotypic techniques fail to reflect the full extent of the diversity of Fasciola spp. In this respect, the use of molecular techniques to identify and differentiate Fasciola spp. offer considerable advantages. The advent of a variety of molecular genetic techniques also provides a powerful method to elucidate many aspects of Fasciola biology, epidemiology, and genetics. However, the discriminatory power of these molecular methods varies, as does the speed and ease of performance and cost. There is a need for the development of new methods to identify the mechanisms underpinning the origin and maintenance of genetic variation within and among Fasciola populations. The increasing application of the current and new methods will yield a much improved understanding of Fasciola epidemiology and evolution as well as more effective means of parasite control. Herein, we provide an overview of the molecular techniques that are being used for the genetic characterization, detection and genotyping of Fasciola spp..

A molecular, genetic and physiological analysis of plant aluminum tolerance (abstract)

International Nuclear Information System (INIS)

Pineros, M.

2005-01-01

Aluminum (Al) toxicity is an important agronomic trait, limiting crop production on acid soils that comprise up to 50% of the world's potentially arable lands. A significant genetic variation in Al tolerance exists in both crop plants and Arabidopsis. The exploitation of this genetic variation to breed crops with increased Al tolerance has been a productive and active area of research, however, the underlying molecular, genetic and physiological bases are still not well understood. Only very recently was the first Al tolerance gene, ALMT1, isolated in wheat and shown to be a novel Al-activated malate transporter. Work in our laboratory has focused on using integrated genomic (gene and protein expression profiling), molecular genetic and physiological approaches to identify novel Al tolerance genes and the physiological mechanisms they control in the cereal crops maize and sorghum, and also in arabidopsis. In sorghum we had previously shown that Al tolerance is the result of a single locus, Alt/sub SB/ which maps to the top of sorghum chromosome 3 in a region totally distinct from where the major Al tolerance maps in wheat and other related members of the Triticeae. Very recently, we have used map-based cloning techniques in sorghum to clone Alt/sub SB/ and have found it is a novel Al tolerance gene. Here we will present a molecular characterization of the Alt/sub SB/ gene and also the physiological mechanism of sorghum Al tolerance it controls. In arabidopsis, we have previously shown that Al tolerance is a quantitative trait and have identified two major Al tolerance QTL on chromosomes 1 and 5. These genes function to confer tolerance via Al via activated root malate release. We found that a member of the arabidopsis gene family that is a close homolog to wheat ALMT1 maps near the largest tolerance QTL on chromosome 1 and have also found this gene encodes the Al-activated malate transport involved in arabidopsis Al tolerance. However, we have clear molecular

Molecular Mechanisms of Neurodegeneration in Spinal Muscular Atrophy

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Saif Ahmad

2016-01-01

Full Text Available Spinal muscular atrophy (SMA is an autosomal recessive motor neuron disease with a high incidence and is the most common genetic cause of infant mortality. SMA is primarily characterized by degeneration of the spinal motor neurons that leads to skeletal muscle atrophy followed by symmetric limb paralysis, respiratory failure, and death. In humans, mutation of the Survival Motor Neuron 1 (SMN1 gene shifts the load of expression of SMN protein to the SMN2 gene that produces low levels of full-length SMN protein because of alternative splicing, which are sufficient for embryonic development and survival but result in SMA. The molecular mechanisms of the (a regulation of SMN gene expression and (b degeneration of motor neurons caused by low levels of SMN are unclear. However, some progress has been made in recent years that have provided new insights into understanding of the cellular and molecular basis of SMA pathogenesis. In this review, we have briefly summarized recent advances toward understanding of the molecular mechanisms of regulation of SMN levels and signaling mechanisms that mediate neurodegeneration in SMA.

Molecular & Genetic Investigation of Tau in Chronic Traumatic Encephalopathy

Science.gov (United States)

2015-10-01

AWARD NUMBER: W81XWH-14-1-0399 TITLE: Molecular & Genetic Investigation of Tau in Chronic Traumatic Encephalopathy PRINCIPAL INVESTIGATOR: John F...Include area code) October 2015 Annual Report 30 Sep 2014 - 29 Sep 2015 Molecular & Genetic Investigation of Tau in Chronic Traumatic Encephalopathy John... encephalopathy (CTE), but the underlying molecular changes remain unclear. Here, biochemical and genetic studies that deepen our understanding of the

The Molecular Genetics of Autism Spectrum Disorders: Genomic Mechanisms, Neuroimmunopathology, and Clinical Implications

Directory of Open Access Journals (Sweden)

Daniel J. Guerra

2011-01-01

Full Text Available Autism spectrum disorders (ASDs have become increasingly common in recent years. The discovery of single-nucleotide polymorphisms and accompanying copy number variations within the genome has increased our understanding of the architecture of the disease. These genetic and genomic alterations coupled with epigenetic phenomena have pointed to a neuroimmunopathological mechanism for ASD. Model animal studies, developmental biology, and affective neuroscience laid a foundation for dissecting the neural pathways impacted by these disease-generating mechanisms. The goal of current autism research is directed toward a systems biological approach to find the most basic genetic and environmental causes to this severe developmental disease. It is hoped that future genomic and neuroimmunological research will be directed toward finding the road toward prevention, treatment, and cure of ASD.

Molecular genetics of breast cancer

International Nuclear Information System (INIS)

Radice, P.; Pierotti, M. A.

1997-01-01

In the last two decades, molecular studies have enlightened the complexity of the genetic alterations that occur in breast cancer cells. To date, more than 40 different genes or loci have been found to be altered in breast carcinomas. Although some of these genes, as for example ERBB2, appear to be mutated in a high proportion of cases, their mechanism of action and their role in the different stages of cancer development are still poorly understood. More recently, two major determinants of the inherited predisposition to breast cancer, BRCA1 and BRCA2, have been isolated. As a consequence, it is now possible to screen families with a positive history of breast carcinomas for the identification of mutations carriers, in order to address these individuals into adequate programs of cancer surveillance and prevention

Guidelines on the use of molecular genetics in reintroduction programs

Science.gov (United States)

Michael K. Schwartz

2005-01-01

The use of molecular genetics can play a key role in reintroduction efforts. Prior to the introduction of any individuals, molecular genetics can be used to identify the most appropriate source population for the reintroduction, ensure that no relic populations exist in the reintroduction area, and guide captive breeding programs. The use of molecular genetics post-...

Application of molecular genetic tools for forest pathology

Science.gov (United States)

Mee-Sook Kim; John Hanna; Amy Ross-Davis; Ned Klopfenstein

2012-01-01

In recent years, advances in molecular genetics have provided powerful tools to address critical issues in forest pathology to help promote resilient forests. Although molecular genetic tools are initially applied to understand individual components of forest pathosystems, forest pathosystems involve dynamic interactions among biotic and abiotic components of the...

Panel 4: Recent Advances in Otitis Media in Molecular Biology, Biochemistry, Genetics, and Animal Models

Science.gov (United States)

Li, Jian-Dong; Hermansson, Ann; Ryan, Allen F.; Bakaletz, Lauren O.; Brown, Steve D.; Cheeseman, Michael T.; Juhn, Steven K.; Jung, Timothy T. K.; Lim, David J.; Lim, Jae Hyang; Lin, Jizhen; Moon, Sung-Kyun; Post, J. Christopher

2014-01-01

Background Otitis media (OM) is the most common childhood bacterial infection and also the leading cause of conductive hearing loss in children. Currently, there is an urgent need for developing novel therapeutic agents for treating OM based on full understanding of molecular pathogenesis in the areas of molecular biology, biochemistry, genetics, and animal model studies in OM. Objective To provide a state-of-the-art review concerning recent advances in OM in the areas of molecular biology, biochemistry, genetics, and animal model studies and to discuss the future directions of OM studies in these areas. Data Sources and Review Methods A structured search of the current literature (since June 2007). The authors searched PubMed for published literature in the areas of molecular biology, biochemistry, genetics, and animal model studies in OM. Results Over the past 4 years, significant progress has been made in the areas of molecular biology, biochemistry, genetics, and animal model studies in OM. These studies brought new insights into our understanding of the molecular and biochemical mechanisms underlying the molecular pathogenesis of OM and helped identify novel therapeutic targets for OM. Conclusions and Implications for Practice Our understanding of the molecular pathogenesis of OM has been significantly advanced, particularly in the areas of inflammation, innate immunity, mucus overproduction, mucosal hyperplasia, middle ear and inner ear interaction, genetics, genome sequencing, and animal model studies. Although these studies are still in their experimental stages, they help identify new potential therapeutic targets. Future preclinical and clinical studies will help to translate these exciting experimental research findings into clinical applications. PMID:23536532

Catecholaminergic systems in stress: structural and molecular genetic approaches.

Science.gov (United States)

Kvetnansky, Richard; Sabban, Esther L; Palkovits, Miklos

2009-04-01

Stressful stimuli evoke complex endocrine, autonomic, and behavioral responses that are extremely variable and specific depending on the type and nature of the stressors. We first provide a short overview of physiology, biochemistry, and molecular genetics of sympatho-adrenomedullary, sympatho-neural, and brain catecholaminergic systems. Important processes of catecholamine biosynthesis, storage, release, secretion, uptake, reuptake, degradation, and transporters in acutely or chronically stressed organisms are described. We emphasize the structural variability of catecholamine systems and the molecular genetics of enzymes involved in biosynthesis and degradation of catecholamines and transporters. Characterization of enzyme gene promoters, transcriptional and posttranscriptional mechanisms, transcription factors, gene expression and protein translation, as well as different phases of stress-activated transcription and quantitative determination of mRNA levels in stressed organisms are discussed. Data from catecholamine enzyme gene knockout mice are shown. Interaction of catecholaminergic systems with other neurotransmitter and hormonal systems are discussed. We describe the effects of homotypic and heterotypic stressors, adaptation and maladaptation of the organism, and the specificity of stressors (physical, emotional, metabolic, etc.) on activation of catecholaminergic systems at all levels from plasma catecholamines to gene expression of catecholamine enzymes. We also discuss cross-adaptation and the effect of novel heterotypic stressors on organisms adapted to long-term monotypic stressors. The extra-adrenal nonneuronal adrenergic system is described. Stress-related central neuronal regulatory circuits and central organization of responses to various stressors are presented with selected examples of regulatory molecular mechanisms. Data summarized here indicate that catecholaminergic systems are activated in different ways following exposure to distinct

Genetics and pathological mechanisms of Usher syndrome.

Science.gov (United States)

Yan, Denise; Liu, Xue Z

2010-06-01

Usher syndrome (USH) comprises a group of autosomal recessively inherited disorders characterized by a dual sensory impairment of the audiovestibular and visual systems. Three major clinical subtypes (USH type I, USH type II and USH type III) are distinguished on the basis of the severity of the hearing loss, the presence or absence of vestibular dysfunction and the age of onset of retinitis pigmentosa (RP). Since the cloning of the first USH gene (MYO7A) in 1995, there have been remarkable advances in elucidating the genetic basis for this disorder, as evidence for 11 distinct loci have been obtained and genes for 9 of them have been identified. The USH genes encode proteins of different classes and families, including motor proteins, scaffold proteins, cell adhesion molecules and transmembrane receptor proteins. Extensive information has emerged from mouse models and molecular studies regarding pathogenesis of this disorder and the wide phenotypic variation in both audiovestibular and/or visual function. A unifying hypothesis is that the USH proteins are integrated into a protein network that regulates hair bundle morphogenesis in the inner ear. This review addresses genetics and pathological mechanisms of USH. Understanding the molecular basis of phenotypic variation and pathogenesis of USH is important toward discovery of new molecular targets for diagnosis, prevention and treatment of this debilitating disorder.

Molecular marker systems for Oenothera genetics.

Science.gov (United States)

Rauwolf, Uwe; Golczyk, Hieronim; Meurer, Jörg; Herrmann, Reinhold G; Greiner, Stephan

2008-11-01

The genus Oenothera has an outstanding scientific tradition. It has been a model for studying aspects of chromosome evolution and speciation, including the impact of plastid nuclear co-evolution. A large collection of strains analyzed during a century of experimental work and unique genetic possibilities allow the exchange of genetically definable plastids, individual or multiple chromosomes, and/or entire haploid genomes (Renner complexes) between species. However, molecular genetic approaches for the genus are largely lacking. In this study, we describe the development of efficient PCR-based marker systems for both the nuclear genome and the plastome. They allow distinguishing individual chromosomes, Renner complexes, plastomes, and subplastomes. We demonstrate their application by monitoring interspecific exchanges of genomes, chromosome pairs, and/or plastids during crossing programs, e.g., to produce plastome-genome incompatible hybrids. Using an appropriate partial permanent translocation heterozygous hybrid, linkage group 7 of the molecular map could be assigned to chromosome 9.8 of the classical Oenothera map. Finally, we provide the first direct molecular evidence that homologous recombination and free segregation of chromosomes in permanent translocation heterozygous strains is suppressed.

Molecular Genetics of Pigment Dispersion Syndrome and Pigmentary Glaucoma: New Insights into Mechanisms

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Adrian A. Lahola-Chomiak

2018-01-01

Full Text Available We explore the ideas and advances surrounding the genetic basis of pigment dispersion syndrome (PDS and pigmentary glaucoma (PG. As PG is the leading cause of nontraumatic blindness in young adults and current tailored interventions have proven ineffective, a better understanding of the underlying causes of PDS, PG, and their relationship is essential. Despite PDS being a subclinical disease, a large proportion of patients progress to PG with associated vision loss. Decades of research have supported a genetic component both for PDS and conversion to PG. We review the body of evidence supporting a genetic basis in humans and animal models and reevaluate classical mechanisms of PDS/PG considering this new evidence.

Molecular Genetics of Pigment Dispersion Syndrome and Pigmentary Glaucoma: New Insights into Mechanisms.

Science.gov (United States)

Lahola-Chomiak, Adrian A; Walter, Michael A

2018-01-01

We explore the ideas and advances surrounding the genetic basis of pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG). As PG is the leading cause of nontraumatic blindness in young adults and current tailored interventions have proven ineffective, a better understanding of the underlying causes of PDS, PG, and their relationship is essential. Despite PDS being a subclinical disease, a large proportion of patients progress to PG with associated vision loss. Decades of research have supported a genetic component both for PDS and conversion to PG. We review the body of evidence supporting a genetic basis in humans and animal models and reevaluate classical mechanisms of PDS/PG considering this new evidence.

Understanding molecular structure from molecular mechanics.

Science.gov (United States)

Allinger, Norman L

2011-04-01

Molecular mechanics gives us a well known model of molecular structure. It is less widely recognized that valence bond theory gives us structures which offer a direct interpretation of molecular mechanics formulations and parameters. The electronic effects well-known in physical organic chemistry can be directly interpreted in terms of valence bond structures, and hence quantitatively calculated and understood. The basic theory is outlined in this paper, and examples of the effects, and their interpretation in illustrative examples is presented.

Child Development and Molecular Genetics: 14 Years Later

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Plomin, Robert

2013-01-01

Fourteen years ago, the first article on molecular genetics was published in this journal: "Child Development, Molecular Genetics, and What to Do With Genes Once They Are Found" (R. Plomin & M. Rutter, 1998). The goal of the article was to outline what developmentalists can do with genes once they are found. These new directions for developmental…

Molecular mechanics of silk nanostructures under varied mechanical loading.

Science.gov (United States)

Bratzel, Graham; Buehler, Markus J

2012-06-01

Spider dragline silk is a self-assembling tunable protein composite fiber that rivals many engineering fibers in tensile strength, extensibility, and toughness, making it one of the most versatile biocompatible materials and most inviting for synthetic mimicry. While experimental studies have shown that the peptide sequence and molecular structure of silk have a direct influence on the stiffness, toughness, and failure strength of silk, few molecular-level analyses of the nanostructure of silk assemblies, in particular, under variations of genetic sequences have been reported. In this study, atomistic-level structures of wildtype as well as modified MaSp1 protein from the Nephila clavipes spider dragline silk sequences, obtained using an in silico approach based on replica exchange molecular dynamics and explicit water molecular dynamics, are subjected to simulated nanomechanical testing using different force-control loading conditions including stretch, pull-out, and peel. The authors have explored the effects of the poly-alanine length of the N. clavipes MaSp1 peptide sequence and identify differences in nanomechanical loading conditions on the behavior of a unit cell of 15 strands with 840-990 total residues used to represent a cross-linking β-sheet crystal node in the network within a fibril of the dragline silk thread. The specific loading condition used, representing concepts derived from the protein network connectivity at larger scales, have a significant effect on the mechanical behavior. Our analysis incorporates stretching, pull-out, and peel testing to connect biochemical features to mechanical behavior. The method used in this study could find broad applications in de novo design of silk-like tunable materials for an array of applications. Copyright © 2011 Wiley Periodicals, Inc.

Genetic diversity in the oral pathogen Porphyromonas gingivalis: molecular mechanisms and biological consequences

Science.gov (United States)

Tribble, Gena D; Kerr, Jennifer E; Wang, Bing-Yan

2013-01-01

Porphyromonas gingivalis is a Gram-negative anaerobic bacterium that colonizes the human oral cavity. It is implicated in the development of periodontitis, a chronic periodontal disease affecting half of the adult population in the USA. To survive in the oral cavity, these bacteria must colonize dental plaque biofilms in competition with other bacterial species. Long-term survival requires P. gingivalis to evade host immune responses, while simultaneously adapting to the changing physiology of the host and to alterations in the plaque biofilm. In reflection of this highly variable niche, P. gingivalis is a genetically diverse species and in this review the authors summarize genetic diversity as it relates to pathogenicity in P. gingivalis. Recent studies revealing a variety of mechanisms by which adaptive changes in genetic content can occur are also reviewed. Understanding the genetic plasticity of P. gingivalis will provide a better framework for understanding the host–microbe interactions associated with periodontal disease. PMID:23642116

Update on the Cytogenetics and Molecular Genetics of Chordoma

Directory of Open Access Journals (Sweden)

Larizza Lidia

2005-02-01

Full Text Available Abstract Chordoma is a rare mesenchymal tumour of complex biology for which only histologic and immunohistochemical criteria have been defined, but no biomarkers predicting the clinical outcome and response to treatment have yet been recognised. We herein review the interdisciplinary information achieved by epidemiologists, neurosurgeons and basic scientists on chordoma, usually a sporadic tumour, which also includes a small fraction of familial cases. Main focus is on the current knowledge of the genetic alterations which might pinpoint candidate genes and molecular mechanisms shared by sporadic and familiar chordomas. Due to the scarcity of the investigated tumour specimens and the multiple chromosome abnormalities found in tumours with aberrant karyotypes, conventional cytogenetics and Fluorescence In Situ Hybridization failed to detect recurrent chordoma-specific chromosomal rearrangements. Genome-wide approaches such as Comparative Genomic Hybridization (CGH are yet at an initial stage of application and should be implemented using BAC arrays either genome-wide or targeting selected genomic regions, disclosed by Loss of Heterozygosity (LOH studies. An LOH region was shown by a systematic study on a consistent number of chordomas to encompass 1p36, a genomic interval where a candidate gene was suggested to reside. Despite the rarity of multiplex families with chordoma impaired linkage studies, a chordoma locus could be mapped to chromosome 7q33 by positive lod score in three independent families. The role in chordomagenesis of the Tuberous Sclerosis Complex (TSC genes has been proved, but the extent of involvement of TSC1 and TSC2 oncosuppressors in chordoma remains to be assessed. In spite of the scarce knowledge on the genetics and molecular biology of chordoma, recent initiation of clinical trials using molecular-targeted therapy, should validate new molecular targets and predict the efficacy of a given therapy. Comparative genetic and

Deciphering molecular circuits from genetic variation underlying transcriptional responsiveness to stimuli.

Science.gov (United States)

Gat-Viks, Irit; Chevrier, Nicolas; Wilentzik, Roni; Eisenhaure, Thomas; Raychowdhury, Raktima; Steuerman, Yael; Shalek, Alex K; Hacohen, Nir; Amit, Ido; Regev, Aviv

2013-04-01

Individual genetic variation affects gene responsiveness to stimuli, often by influencing complex molecular circuits. Here we combine genomic and intermediate-scale transcriptional profiling with computational methods to identify variants that affect the responsiveness of genes to stimuli (responsiveness quantitative trait loci or reQTLs) and to position these variants in molecular circuit diagrams. We apply this approach to study variation in transcriptional responsiveness to pathogen components in dendritic cells from recombinant inbred mouse strains. We identify reQTLs that correlate with particular stimuli and position them in known pathways. For example, in response to a virus-like stimulus, a trans-acting variant responds as an activator of the antiviral response; using RNA interference, we identify Rgs16 as the likely causal gene. Our approach charts an experimental and analytic path to decipher the mechanisms underlying genetic variation in circuits that control responses to stimuli.

Molecular mechanisms in gliomagenesis

DEFF Research Database (Denmark)

Hulleman, Esther; Helin, Kristian

2005-01-01

Glioma, and in particular high-grade astrocytoma termed glioblastoma multiforme (GBM), is the most common primary tumor of the brain. Primarily because of its diffuse nature, there is no effective treatment for GBM, and relatively little is known about the processes by which it develops. Therefore......, in order to design novel therapies and treatments for GBM, research has recently intensified to identify the cellular and molecular mechanisms leading to GBM formation. Modeling of astrocytomas by genetic manipulation of mice suggests that deregulation of the pathways that control gliogenesis during normal...... brain development, such as the differentiation of neural stem cells (NSCs) into astrocytes, might contribute to GBM formation. These pathways include growth factor-induced signal transduction routes and processes that control cell cycle progression, such as the p16-CDK4-RB and the ARF-MDM2-p53 pathways...

Advances in genetics. Volume 22: Molecular genetics of plants

International Nuclear Information System (INIS)

Scandalios, J.G.; Caspari, E.W.

1984-01-01

This book contains the following four chapters: Structural Variation in Mitochondrial DNA; The Structure and Expression of Nuclear Genes in Higher Plants; Chromatin Structure and Gene Regulation in Higher Plants; and The Molecular Genetics of Crown Gall Tumorigenesis

Molecular and genetic insights into an infantile epileptic encephalopathy-CDKL5 disorder

Institute of Scientific and Technical Information of China (English)

Ailing Zhou; Song Han; Zhaolan Joe Zhou

2017-01-01

BACKGROUND:The discovery that mutations in cyclin-dependent kinase-like 5 (CDKL5) gene are associated with infantile epileptic encephalopathy has stimulated world-wide research effort to understand the molecular and genetic basis of CDKL5 disorder.Given the large number of literature published thus far,this review aims to summarize current genetic studies,draw a consensus on proposed molecular functions,and point to gaps of knowledge in CDKL5 research.METHODS:A systematic review process was conducted using the PubMed search engine focusing on CDKL5 studies in the recent ten years.We analyzed these publications and summarized the findings into four sections:genetic studies,CDKL5 expression pattems,molecular functions,and animal models.We also discussed challenges and future directions in each section.RESULTS:On the clinical side,CDKL5 disorder is characterized by early onset epileptic seizures,intellectual disability,and stereotypical behaviors.On the research side,a series of molecular and genetic studies in human patients,cell cultures and animal models have established the causality of CDKL5 to the infantile epileptic encephalopathy,and pointed to a key role for CDKL5 in regulating neuronal function in the brain.Mouse models of CDKL5 disorder have also been developed,and notably,manifest behavioral phenotypes,mimicking numerous clinical symptoms of CDKL5 disorder and advancing CDKL5 research to the preclinical stage.CONCLUSIONS:Given what we have leamed thus far,future identification of robust,quantitative,and sensitive outcome measures would be the key in animal model studies,particularly in heterozygous females.In the meantime,molecular and cellular studies of CDKL5 should focus on mechanism-based investigation and aim to uncover druggable targets that offer the potential to rescue or ameliorate CDKL5 disorder-related phenotypes.

Molecular and genetic insights into an infantile epileptic encephalopathy - CDKL5 disorder.

Science.gov (United States)

Zhou, Ailing; Han, Song; Zhou, Zhaolan Joe

2017-02-01

The discovery that mutations in cyclin-dependent kinase-like 5 ( CDKL5 ) gene are associated with infantile epileptic encephalopathy has stimulated world-wide research effort to understand the molecular and genetic basis of CDKL5 disorder. Given the large number of literature published thus far, this review aims to summarize current genetic studies, draw a consensus on proposed molecular functions, and point to gaps of knowledge in CDKL5 research. A systematic review process was conducted using the PubMed search engine focusing on CDKL5 studies in the recent ten years. We analyzed these publications and summarized the findings into four sections: genetic studies, CDKL5 expression patterns, molecular functions, and animal models. We also discussed challenges and future directions in each section. On the clinical side, CDKL5 disorder is characterized by early onset epileptic seizures, intellectual disability, and stereotypical behaviors. On the research side, a series of molecular and genetic studies in human patients, cell cultures and animal models have established the causality of CDKL5 to the infantile epileptic encephalopathy, and pointed to a key role for CDKL5 in regulating neuronal function in the brain. Mouse models of CDKL5 disorder have also been developed, and notably, manifest behavioral phenotypes, mimicking numerous clinical symptoms of CDKL5 disorder and advancing CDKL5 research to the preclinical stage. Given what we have learned thus far, future identification of robust, quantitative, and sensitive outcome measures would be the key in animal model studies, particularly in heterozygous females. In the meantime, molecular and cellular studies of CDKL5 should focus on mechanism-based investigation and aim to uncover druggable targets that offer the potential to rescue or ameliorate CDKL5 disorder-related phenotypes.

The Molecular Genetics of von Willebrand Disease

Directory of Open Access Journals (Sweden)

Ergül Berber

2012-12-01

Full Text Available Quantitative and/or qualitative deficiency of von Willebrand factor (vWF is associated with the most common inherited bleeding disease von Willebrand disease (vWD. vWD is a complex disease with clinical and genetic heterogeneity. Incomplete penetrance and variable expression due to genetic and environmental factors contribute to its complexity. vWD also has a complex molecular pathogenesis. Some vWF gene mutations are associated with the affected vWF biosynthesis and multimerization, whereas others are associated with increased clearance and functional impairment. Moreover, in addition to a particular mutation, type O blood may result in the more severe phenotype. The present review aimed to provide a summary of the current literature on the molecular genetics of vWD.

The molecular genetics of von Willebrand disease.

Science.gov (United States)

Berber, Ergül

2012-12-01

Quantitative and/or qualitative deficiency of von Willebrand factor (vWF) is associated with the most common inherited bleeding disease von Willebrand disease (vWD). vWD is a complex disease with clinical and genetic heterogeneity. Incomplete penetrance and variable expression due to genetic and environmental factors contribute to its complexity. vWD also has a complex molecular pathogenesis. Some vWF gene mutations are associated with the affected vWF biosynthesis and multimerization, whereas others are associated with increased clearance and functional impairment. Moreover, in addition to a particular mutation, type O blood may result in the more severe phenotype. The present review aimed to provide a summary of the current literature on the molecular genetics of vWD. None declared.

Molecular genetic studies in flax (Linum usitatissimum L.)

NARCIS (Netherlands)

Vromans, J.

2006-01-01

In this thesis five molecular genetic studies on flax ( Linum usitatissimum L.) are described, of which two chapters aim to characterize the genetic structure and the amount of genetic diversity in the primary and secondary gene pool of the crop species. Three chapters describe the development of

Molecular genetics of dyslexia: an overview.

Science.gov (United States)

Carrion-Castillo, Amaia; Franke, Barbara; Fisher, Simon E

2013-11-01

Dyslexia is a highly heritable learning disorder with a complex underlying genetic architecture. Over the past decade, researchers have pinpointed a number of candidate genes that may contribute to dyslexia susceptibility. Here, we provide an overview of the state of the art, describing how studies have moved from mapping potential risk loci, through identification of associated gene variants, to characterization of gene function in cellular and animal model systems. Work thus far has highlighted some intriguing mechanistic pathways, such as neuronal migration, axon guidance, and ciliary biology, but it is clear that we still have much to learn about the molecular networks that are involved. We end the review by highlighting the past, present, and future contributions of the Dutch Dyslexia Programme to studies of genetic factors. In particular, we emphasize the importance of relating genetic information to intermediate neurobiological measures, as well as the value of incorporating longitudinal and developmental data into molecular designs. Copyright © 2013 John Wiley & Sons, Ltd.

Assessing Date Palm Genetic Diversity Using Different Molecular Markers.

Science.gov (United States)

Atia, Mohamed A M; Sakr, Mahmoud M; Adawy, Sami S

2017-01-01

Molecular marker technologies which rely on DNA analysis provide powerful tools to assess biodiversity at different levels, i.e., among and within species. A range of different molecular marker techniques have been developed and extensively applied for detecting variability in date palm at the DNA level. Recently, the employment of gene-targeting molecular marker approaches to study biodiversity and genetic variations in many plant species has increased the attention of researchers interested in date palm to carry out phylogenetic studies using these novel marker systems. Molecular markers are good indicators of genetic distances among accessions, because DNA-based markers are neutral in the face of selection. Here we describe the employment of multidisciplinary molecular marker approaches: amplified fragment length polymorphism (AFLP), start codon targeted (SCoT) polymorphism, conserved DNA-derived polymorphism (CDDP), intron-targeted amplified polymorphism (ITAP), simple sequence repeats (SSR), and random amplified polymorphic DNA (RAPD) to assess genetic diversity in date palm.

Molecular characterization and assessment of genetic diversity of ...

African Journals Online (AJOL)

R Madhusudhana

genetic diversity available at molecular level among a set of phenotypically different ... allele matching and cluster analysis based on unweighted neighbor- joining (Gascuel, 1997) ..... on isozyme data-a simulation study. Theor. Appl. Genet.

A high-resolution gene expression atlas of epistasis between gene-specific transcription factors exposes potential mechanisms for genetic interactions.

Science.gov (United States)

Sameith, Katrin; Amini, Saman; Groot Koerkamp, Marian J A; van Leenen, Dik; Brok, Mariel; Brabers, Nathalie; Lijnzaad, Philip; van Hooff, Sander R; Benschop, Joris J; Lenstra, Tineke L; Apweiler, Eva; van Wageningen, Sake; Snel, Berend; Holstege, Frank C P; Kemmeren, Patrick

2015-12-23

Genetic interactions, or non-additive effects between genes, play a crucial role in many cellular processes and disease. Which mechanisms underlie these genetic interactions has hardly been characterized. Understanding the molecular basis of genetic interactions is crucial in deciphering pathway organization and understanding the relationship between genotype, phenotype and disease. To investigate the nature of genetic interactions between gene-specific transcription factors (GSTFs) in Saccharomyces cerevisiae, we systematically analyzed 72 GSTF pairs by gene expression profiling double and single deletion mutants. These pairs were selected through previously published growth-based genetic interactions as well as through similarity in DNA binding properties. The result is a high-resolution atlas of gene expression-based genetic interactions that provides systems-level insight into GSTF epistasis. The atlas confirms known genetic interactions and exposes new ones. Importantly, the data can be used to investigate mechanisms that underlie individual genetic interactions. Two molecular mechanisms are proposed, "buffering by induced dependency" and "alleviation by derepression". These mechanisms indicate how negative genetic interactions can occur between seemingly unrelated parallel pathways and how positive genetic interactions can indirectly expose parallel rather than same-pathway relationships. The focus on GSTFs is important for understanding the transcription regulatory network of yeast as it uncovers details behind many redundancy relationships, some of which are completely new. In addition, the study provides general insight into the complex nature of epistasis and proposes mechanistic models for genetic interactions, the majority of which do not fall into easily recognizable within- or between-pathway relationships.

Improving Molecular Genetic Test Utilization through Order Restriction, Test Review, and Guidance.

Science.gov (United States)

Riley, Jacquelyn D; Procop, Gary W; Kottke-Marchant, Kandice; Wyllie, Robert; Lacbawan, Felicitas L

2015-05-01

The ordering of molecular genetic tests by health providers not well trained in genetics may have a variety of untoward effects. These include the selection of inappropriate tests, the ordering of panels when the assessment of individual or fewer genes would be more appropriate, inaccurate result interpretation and inappropriate patient guidance, and significant unwarranted cost expenditure. We sought to improve the utilization of molecular genetic tests by requiring providers without specialty training in genetics to use genetic counselors and molecular genetic pathologists to assist in test selection. We used a genetic and genomic test review process wherein the laboratory-based genetic counselor performed the preanalytic assessment of test orders and test triage. Test indication and clinical findings were evaluated against the test panel composition, methods, and test limitations under the supervision of the molecular genetic pathologist. These test utilization management efforts resulted in a decrease in genetic test ordering and a gross cost savings of $1,531,913 since the inception of these programs in September 2011 through December 2013. The combination of limiting the availability of complex genetic tests and providing guidance regarding appropriate test strategies is an effective way to improve genetic tests, contributing to judicious use of limited health care resources. Copyright © 2015 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

Intelligent DNA-based molecular diagnostics using linked genetic markers

Energy Technology Data Exchange (ETDEWEB)

Pathak, D.K.; Perlin, M.W.; Hoffman, E.P.

1994-12-31

This paper describes a knowledge-based system for molecular diagnostics, and its application to fully automated diagnosis of X-linked genetic disorders. Molecular diagnostic information is used in clinical practice for determining genetic risks, such as carrier determination and prenatal diagnosis. Initially, blood samples are obtained from related individuals, and PCR amplification is performed. Linkage-based molecular diagnosis then entails three data analysis steps. First, for every individual, the alleles (i.e., DNA composition) are determined at specified chromosomal locations. Second, the flow of genetic material among the individuals is established. Third, the probability that a given individual is either a carrier of the disease or affected by the disease is determined. The current practice is to perform each of these three steps manually, which is costly, time consuming, labor-intensive, and error-prone. As such, the knowledge-intensive data analysis and interpretation supersede the actual experimentation effort as the major bottleneck in molecular diagnostics. By examining the human problem solving for the task, we have designed and implemented a prototype knowledge-based system capable of fully automating linkage-based molecular diagnostics in X-linked genetic disorders, including Duchenne Muscular Dystrophy (DMD). Our system uses knowledge-based interpretation of gel electrophoresis images to determine individual DNA marker labels, a constraint satisfaction search for consistent genetic flow among individuals, and a blackboard-style problem solver for risk assessment. We describe the system`s successful diagnosis of DMD carrier and affected individuals from raw clinical data.

Towards mosquito sterile insect technique programmes: Exploring genetic, molecular, mechanical and behavioural methods of sex separation in mosquitoes

Czech Academy of Sciences Publication Activity Database

Gilles, J. R. L.; Schetelig, M. F.; Scolari, F.; Marec, František; Capurro, M.L.; Franz, G.; Bourtzis, K.

132S, č. 1 (2014), S178-S187 ISSN 0001-706X R&D Projects: GA ČR GA523/09/2106 Grant - others:Deutsche Forschungsgemeinschalft(DE) SCHE 1833/1 Institutional support: RVO:60077344 Keywords : female elimination * vector control * genetic sexing strains (GSS) Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.270, year: 2014 http://www.sciencedirect.com/science/article/pii/S0001706X13002209?via=ihub

Molecular genetics of early-onset Alzheimer's disease revisited.

Science.gov (United States)

Cacace, Rita; Sleegers, Kristel; Van Broeckhoven, Christine

2016-06-01

As the discovery of the Alzheimer's disease (AD) genes, APP, PSEN1, and PSEN2, in families with autosomal dominant early-onset AD (EOAD), gene discovery in familial EOAD came more or less to a standstill. Only 5% of EOAD patients are carrying a pathogenic mutation in one of the AD genes or a apolipoprotein E (APOE) risk allele ε4, most of EOAD patients remain unexplained. Here, we aimed at summarizing the current knowledge of EOAD genetics and its role in ongoing approaches to understand the biology of AD and disease symptomatology as well as developing new therapeutics. Next, we explored the possible molecular mechanisms that might underlie the missing genetic etiology of EOAD and discussed how the use of massive parallel sequencing technologies triggered novel gene discoveries. To conclude, we commented on the relevance of reinvestigating EOAD patients as a means to explore potential new avenues for translational research and therapeutic discoveries. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Molecular and genetic insights into an infantile epileptic encephalopathy – CDKL5 disorder

Science.gov (United States)

Zhou, Ailing; Han, Song

2017-01-01

Background The discovery that mutations in cyclin-dependent kinase-like 5 (CDKL5) gene are associated with infantile epileptic encephalopathy has stimulated world-wide research effort to understand the molecular and genetic basis of CDKL5 disorder. Given the large number of literature published thus far, this review aims to summarize current genetic studies, draw a consensus on proposed molecular functions, and point to gaps of knowledge in CDKL5 research. Methods A systematic review process was conducted using the PubMed search engine focusing on CDKL5 studies in the recent ten years. We analyzed these publications and summarized the findings into four sections: genetic studies, CDKL5 expression patterns, molecular functions, and animal models. We also discussed challenges and future directions in each section. Results On the clinical side, CDKL5 disorder is characterized by early onset epileptic seizures, intellectual disability, and stereotypical behaviors. On the research side, a series of molecular and genetic studies in human patients, cell cultures and animal models have established the causality of CDKL5 to the infantile epileptic encephalopathy, and pointed to a key role for CDKL5 in regulating neuronal function in the brain. Mouse models of CDKL5 disorder have also been developed, and notably, manifest behavioral phenotypes, mimicking numerous clinical symptoms of CDKL5 disorder and advancing CDKL5 research to the preclinical stage. Conclusions Given what we have learned thus far, future identification of robust, quantitative, and sensitive outcome measures would be the key in animal model studies, particularly in heterozygous females. In the meantime, molecular and cellular studies of CDKL5 should focus on mechanism-based investigation and aim to uncover druggable targets that offer the potential to rescue or ameliorate CDKL5 disorder-related phenotypes. PMID:28580010

Genetic Mechanisms of Antibiotic Resistance and the Role of Antibiotic Adjuvants.

Science.gov (United States)

Pontes, Daniela Santos; de Araujo, Rodrigo Santos Aquino; Dantas, Natalina; Scotti, Luciana; Scotti, Marcus Tullius; de Moura, Ricardo Olimpio; Mendonca-Junior, Francisco Jaime Bezerra

2018-01-01

The ever increasing number of multidrug-resistant microorganism pathogens has become a great and global public health threat. Antibiotic mechanisms of action and the opposing mechanisms of resistance are intimately associated, but comprehension of the biochemical and molecular functions of such drugs is not a simple exercise. Both the environment, and genetic settings contribute to alterations in phenotypic resistance (natural bacterial evolution), and make it difficult to control the emergence and impacts of antibiotic resistance. Under such circumstances, comprehension of how bacteria develop and/or acquire antibiotic resistance genes (ARG) has a critical role in developing propositions to fight against these superbugs, and to search for new drugs. In this review, we present and discuss both general information and examples of common genetic and molecular mechanisms related to antibiotic resistance, as well as how the expression and interactions of ARGs are important to drug resistance. At the same time, we focus on the recent achievements in the search for antibiotic adjuvants, which help combat antibiotic resistance through deactivation of bacterial mechanisms of action such as β-lactamases. Recent advances involving the use of anti-resistance drugs such as: efflux pump inhibitors; anti-virulence drugs; drugs against quorum sensing; and against type II/III secretion systems are revealed. Such antibiotic adjuvants (as explored herein) collaborate against the problems of antibiotic resistance, and may restore or prolong the therapeutic activity of known antibiotics. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

NEW MOLECULAR TECHNOLOGIES IN GENETIC DIAGNOSIS OF MALE INFERTILITY

Directory of Open Access Journals (Sweden)

V. B. Chernykh

2017-01-01

Full Text Available In recent years, the accelerated development of technologies in the field of molecular genetics and cytogenetics has led to significant opportunities of the research and diagnosis of mutations and variations of the genome. This article provides a brief review of new molecular technology, also as the results of their use in reproductive medicine and their perspectives in the genetic diagnosis of male infertility. 

Comparative analysis of the molecular mechanisms of recombination in hepatitis C virus

DEFF Research Database (Denmark)

Galli, Andrea; Bukh, Jens

2014-01-01

Genetic recombination is an important evolutionary mechanism for RNA viruses. The significance of this phenomenon for hepatitis C virus (HCV) has recently become evident, with the identification of circulating recombinant forms in HCV-infected individuals and by novel data from studies permitted...... by advances in HCV cell culture systems and genotyping protocols. HCV is readily able to produce viable recombinants, using replicative and non-replicative molecular mechanisms. However, our knowledge of the required molecular mechanisms remains limited. Understanding how HCV recombines might be instrumental...... for a better monitoring of global epidemiology, to clarify the virus evolution, and evaluate the impact of recombinant forms on the efficacy of oncoming combination drug therapies. For the latter, frequency and location of recombination events could affect the efficacy of multidrug regimens. This review...

Tumor Heterogeneity: Mechanisms and Bases for a Reliable Application of Molecular Marker Design

Science.gov (United States)

Diaz-Cano, Salvador J.

2012-01-01

Tumor heterogeneity is a confusing finding in the assessment of neoplasms, potentially resulting in inaccurate diagnostic, prognostic and predictive tests. This tumor heterogeneity is not always a random and unpredictable phenomenon, whose knowledge helps designing better tests. The biologic reasons for this intratumoral heterogeneity would then be important to understand both the natural history of neoplasms and the selection of test samples for reliable analysis. The main factors contributing to intratumoral heterogeneity inducing gene abnormalities or modifying its expression include: the gradient ischemic level within neoplasms, the action of tumor microenvironment (bidirectional interaction between tumor cells and stroma), mechanisms of intercellular transference of genetic information (exosomes), and differential mechanisms of sequence-independent modifications of genetic material and proteins. The intratumoral heterogeneity is at the origin of tumor progression and it is also the byproduct of the selection process during progression. Any analysis of heterogeneity mechanisms must be integrated within the process of segregation of genetic changes in tumor cells during the clonal expansion and progression of neoplasms. The evaluation of these mechanisms must also consider the redundancy and pleiotropism of molecular pathways, for which appropriate surrogate markers would support the presence or not of heterogeneous genetics and the main mechanisms responsible. This knowledge would constitute a solid scientific background for future therapeutic planning. PMID:22408433

Molecular diversity and genetic relationships in Secale

Indian Academy of Sciences (India)

Molecular diversity and genetic relationships in Secale. E. Santos, M. Matos, P. Silva, A. M. Figueiras, C. Benito and O. Pinto-Carnide. J. Genet. 95, 273–281. Table 1. RAPD and ISSR primers used in this study. Primer. 5 –3. Primer. 5 –3. RAPDs (Operon). A1. CAGGCCCTTC. C5. CATGACCGCC. A4. AATCGGGCTG. C6.

Pitfall in quantum mechanical/molecular mechanical molecular dynamics simulation of small solutes in solution.

Science.gov (United States)

Hu, Hao; Liu, Haiyan

2013-05-30

Developments in computing hardware and algorithms have made direct molecular dynamics simulation with the combined quantum mechanical/molecular mechanical methods affordable for small solute molecules in solution, in which much improved accuracy can be obtained via the quantum mechanical treatment of the solute molecule and even sometimes water molecules in the first solvation shell. However, unlike the conventional molecular mechanical simulations of large molecules, e.g., proteins, in solutions, special care must be taken in the technical details of the simulation, including the thermostat of the solute/solvent system, so that the conformational space of the solute molecules can be properly sampled. We show here that the common setup for classical molecular mechanical molecular dynamics simulations, such as the Berendsen or single Nose-Hoover thermostat, and/or rigid water models could lead to pathological sampling of the solutes' conformation. In the extreme example of a methanol molecule in aqueous solution, improper and sluggish setups could generate two peaks in the distribution of the O-H bond length. We discuss the factors responsible for this somewhat unexpected result and evoke a simple and ancient technical fix-up to resolve this problem.

RESEARCH NOTE Molecular genetic analysis of consanguineous ...

Indian Academy of Sciences (India)

Navya

Molecular genetic analysis of consanguineous families with primary microcephaly ... Translational Research Institute, Academic Health System, Hamad Medical ..... bridging the gap between homozygosity mapping and deep sequencing.

Genetic dissimilarity among sweet potato genotypes using morphological and molecular descriptors

Directory of Open Access Journals (Sweden)

Elisângela Knoblauch Viega de Andrade

2017-08-01

Full Text Available This study aimed to evaluate the genetic dissimilarity among sweet potato genotypes using morphological and molecular descriptors. The experiment was conducted in the Olericulture Sector at Federal University of Jequitinhonha and Mucuri Valleys (UFVJM and evaluated 60 sweet potato genotypes. For morphological characterization, 24 descriptors were used. For molecular characterization, 11 microsatellite primers specific for sweet potatoes were used, obtaining 210 polymorphic bands. Morphological and molecular diversity was obtained by dissimilarity matrices based on the coefficient of simple matching and the Jaccard index for morphological and molecular data, respectively. From these matrices, dendrograms were built. There is a large amount of genetic variability among sweet potato genotypes of the germplasm bank at UFVJM based on morphological and molecular characterizations. There was no duplicate suspicion or strong association between morphological and molecular analyses. Divergent accessions have been identified by molecular and morphological analyses, which can be used as parents in breeding programmes to produce progenies with high genetic variability.

A methodological overview on molecular preimplantation genetic diagnosis and screening: a genomic future?

Science.gov (United States)

Vendrell, Xavier; Bautista-Llácer, Rosa

2012-12-01

The genetic diagnosis and screening of preimplantation embryos generated by assisted reproduction technology has been consolidated in the prenatal care framework. The rapid evolution of DNA technologies is tending to molecular approaches. Our intention is to present a detailed methodological view, showing different diagnostic strategies based on molecular techniques that are currently applied in preimplantation genetic diagnosis. The amount of DNA from one single, or a few cells, obtained by embryo biopsy is a limiting factor for the molecular analysis. In this sense, genetic laboratories have developed molecular protocols considering this restrictive condition. Nevertheless, the development of whole-genome amplification methods has allowed preimplantation genetic diagnosis for two or more indications simultaneously, like the selection of histocompatible embryos plus detection of monogenic diseases or aneuploidies. Moreover, molecular techniques have permitted preimplantation genetic screening to progress, by implementing microarray-based comparative genome hybridization. Finally, a future view of the embryo-genetics field based on molecular advances is proposed. The normalization, cost-effectiveness analysis, and new technological tools are the next topics for preimplantation genetic diagnosis and screening. Concomitantly, these additions to assisted reproduction technologies could have a positive effect on the schedules of preimplantation studies.

Epidemiological and genetic clues for molecular mechanisms involved in uterine leiomyoma development and growth.

Science.gov (United States)

Commandeur, Arno E; Styer, Aaron K; Teixeira, Jose M

2015-01-01

, rodent xenograft, naturally mutant, and genetically modified models used to study possible molecular mechanisms of leiomyoma development and growth are described. Particular emphasis is placed on known links to fibrosis, hypertrophy, and hyperplasia and genes that are potentially important in these processes. Menstrual cycle-related injury and repair and coinciding hormonal cycling appears to affect myometrial stem cells that, at a certain stage of fibroid development, often obtain cytogenetic aberrations and mutations of Mediator complex subunit 12 (MED12). Mammalian target of rapamycin (mTOR), a master regulator of proliferation, is activated in many of these tumors, possibly by mechanisms that are similar to some human fibrosis syndromes and/or by mutation of upstream tumor suppressor genes. Animal models of the disease support some of these dysregulated pathways in fibroid etiology or pathogenesis, but none are definitive. All of this suggests that there are likely several key mechanisms involved in the disease that, in addition to increasing the complexity of uterine fibroid pathobiology, offer possible approaches for patient-specific therapies. A final model that incorporates many of these reported mechanisms is presented with a discussion of their implications for leiomyoma clinical practice. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Molecular Genetic Studies of Some Eye Diseases Affecting the ...

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. Molecular Genetic Studies of Some Eye Diseases Affecting the Indian Population. Single gene disorders. Complex eye diseases. Genotype-phenotype correlation. Molecular diagnostics.

Molecular and Genetic Determinants of Glioma Cell Invasion

Directory of Open Access Journals (Sweden)

Kenta Masui

2017-12-01

Full Text Available A diffusely invasive nature is a major obstacle in treating a malignant brain tumor, “diffuse glioma”, which prevents neurooncologists from surgically removing the tumor cells even in combination with chemotherapy and radiation. Recently updated classification of diffuse gliomas based on distinct genetic and epigenetic features has culminated in a multilayered diagnostic approach to combine histologic phenotypes and molecular genotypes in an integrated diagnosis. However, it is still a work in progress to decipher how the genetic aberrations contribute to the aggressive nature of gliomas including their highly invasive capacity. Here we depict a set of recent discoveries involving molecular genetic determinants of the infiltrating nature of glioma cells, especially focusing on genetic mutations in receptor tyrosine kinase pathways and metabolic reprogramming downstream of common cancer mutations. The specific biology of glioma cell invasion provides an opportunity to explore the genotype-phenotype correlation in cancer and develop novel glioma-specific therapeutic strategies for this devastating disease.

Molecular characterization of genetic diversity in some durum wheat ...

African Journals Online (AJOL)

Molecular characterization of genetic diversity in some durum wheat ... African Journal of Biotechnology ... Thus, RAPD offer a potentially simple, rapid and reliable method to evaluate genetic variation and relatedness among ten wheat ...

Micropropagation, genetic engineering, and molecular biology of Populus

Science.gov (United States)

N. B. Klopfenstein; Y. W. Chun; M. -S. Kim; M. A. Ahuja; M. C. Dillon; R. C. Carman; L. G. Eskew

1997-01-01

Thirty-four Populus biotechnology chapters, written by 85 authors, are comprised in 5 sections: 1) in vitro culture (micropropagation, somatic embryogenesis, protoplasts, somaclonal variation, and germplasm preservation); 2) transformation and foreign gene expression; 3) molecular biology (molecular/genetic characterization); 4) biotic and abiotic resistance (disease,...

Recent advances in the molecular genetics of the lignin degrading fungus, phanerochaete chrysosporium

International Nuclear Information System (INIS)

Covert, S.F.

1991-01-01

During the past several years, molecular genetics research on phanerochaete chrysosporium, a white-rot basidiomycete, has increased dramatically. It is known that families of highly homologous, clustered genes encode the lignin peroxidases. The same appears to be true with the exocellobiohydrolase genes. Functional domains and active sites have been tentatively identified from the deduced amino acid sequences of these genes. Current investigations focus on elucidating the genomic organization of gene families, the mechanism(s) of gene regulation, and the role and interaction of specific gene products in lignocellulose degradation. (author)

Classical and molecular genetics of malignant melanoma and dysplastic naevi

International Nuclear Information System (INIS)

Traupe, H.; Macher, E.

1988-01-01

The authors conclude that the prevailing concept of monogenic autosomaldominant inheritance of dysplastic naevi and familial melanoma is not compatible with the principles of formal (Mendelian) genetics. The concept of polygenic inheritance offers instead a sound basis to explain familial aggregation of dysplastic naevi and melanoma. The various genes involved have not yet been identified at the molecular level. The recent advances made possible by modern DNA technology have given us a new view of carcinogenesis. In human malignant melanoma, chromosomes 1, 6, 7 are of particular interest and oncogenes located on these chromosomes may be involved with the initiation, promotion and progression of melanoma. Carcinogenesis is viewed as a multistep process and even tumour initiation requires the input of at least two independent oncogenes. Molecular genetics thus adds an important argument for the existence of a polygenic predisposition to melanoma. The concept of polygenic inheritance is not restricted to familial melanoma, but implies that all melanomas basically share the same predisposition and are due to similar genetic mechanisms. In some patients an inherited genetic predisposition is of great importance, whereas in others (the majority) environmental factors (e.g. UV-light-induced mutations) will be the cause of initial steps in the malignant transformation. The concept of polygenic inheritance has consequences for the management of our patients. In contrast to simple Mendelian inheritance, the risk for dysplastic naevi and melanoma is not constantly 50%, but increases with the number of family members already affected. Persons belonging to families with more that 2 affected close relatives should be considered at high risk regardless of the dysplastic naevus status. Strict surveillance of this patient group is warranted for melanoma prevention

Tumor Heterogeneity: Mechanisms and Bases for a Reliable Application of Molecular Marker Design

Directory of Open Access Journals (Sweden)

Salvador J. Diaz-Cano

2012-02-01

Full Text Available Tumor heterogeneity is a confusing finding in the assessment of neoplasms, potentially resulting in inaccurate diagnostic, prognostic and predictive tests. This tumor heterogeneity is not always a random and unpredictable phenomenon, whose knowledge helps designing better tests. The biologic reasons for this intratumoral heterogeneity would then be important to understand both the natural history of neoplasms and the selection of test samples for reliable analysis. The main factors contributing to intratumoral heterogeneity inducing gene abnormalities or modifying its expression include: the gradient ischemic level within neoplasms, the action of tumor microenvironment (bidirectional interaction between tumor cells and stroma, mechanisms of intercellular transference of genetic information (exosomes, and differential mechanisms of sequence-independent modifications of genetic material and proteins. The intratumoral heterogeneity is at the origin of tumor progression and it is also the byproduct of the selection process during progression. Any analysis of heterogeneity mechanisms must be integrated within the process of segregation of genetic changes in tumor cells during the clonal expansion and progression of neoplasms. The evaluation of these mechanisms must also consider the redundancy and pleiotropism of molecular pathways, for which appropriate surrogate markers would support the presence or not of heterogeneous genetics and the main mechanisms responsible. This knowledge would constitute a solid scientific background for future therapeutic planning.

Genetic Breeding and Diversity of the Genus Passiflora: Progress and Perspectives in Molecular and Genetic Studies

Directory of Open Access Journals (Sweden)

Carlos Bernard M. Cerqueira-Silva

2014-08-01

Full Text Available Despite the ecological and economic importance of passion fruit (Passiflora spp., molecular markers have only recently been utilized in genetic studies of this genus. In addition, both basic genetic researches related to population studies and pre-breeding programs of passion fruit remain scarce for most Passiflora species. Considering the number of Passiflora species and the increasing use of these species as a resource for ornamental, medicinal, and food purposes, the aims of this review are the following: (i to present the current condition of the passion fruit crop; (ii to quantify the applications and effects of using molecular markers in studies of Passiflora; (iii to present the contributions of genetic engineering for passion fruit culture; and (iv to discuss the progress and perspectives of this research. Thus, the present review aims to summarize and discuss the relationship between historical and current progress on the culture, breeding, and molecular genetics of passion fruit.

Genetics and molecular biology of breast cancer

Energy Technology Data Exchange (ETDEWEB)

King, M.C. [California Univ., Berkeley, CA (United States); Lippman, M. [Georgetown Univ. Medical Center, Washington, DC (United States)] [comps.

1992-12-31

This volume contains the abstracts of oral presentations and poster sessions presented at the Cold Springs Harbor Meeting on Cancer Cells, this meeting entitled Genetics and Molecular Biology of Breast Cancer.

Molecular markers: a potential resource for ginger genetic diversity studies.

Science.gov (United States)

Ismail, Nor Asiah; Rafii, M Y; Mahmud, T M M; Hanafi, M M; Miah, Gous

2016-12-01

Ginger is an economically important and valuable plant around the world. Ginger is used as a food, spice, condiment, medicine and ornament. There is available information on biochemical aspects of ginger, but few studies have been reported on its molecular aspects. The main objective of this review is to accumulate the available molecular marker information and its application in diverse ginger studies. This review article was prepared by combing material from published articles and our own research. Molecular markers allow the identification and characterization of plant genotypes through direct access to hereditary material. In crop species, molecular markers are applied in different aspects and are useful in breeding programs. In ginger, molecular markers are commonly used to identify genetic variation and classify the relatedness among varieties, accessions, and species. Consequently, it provides important input in determining resourceful management strategies for ginger improvement programs. Alternatively, a molecular marker could function as a harmonizing tool for documenting species. This review highlights the application of molecular markers (isozyme, RAPD, AFLP, SSR, ISSR and others such as RFLP, SCAR, NBS and SNP) in genetic diversity studies of ginger species. Some insights on the advantages of the markers are discussed. The detection of genetic variation among promising cultivars of ginger has significance for ginger improvement programs. This update of recent literature will help researchers and students select the appropriate molecular markers for ginger-related research.

Supplementary data: Molecular assessment of genetic diversity in ...

Indian Academy of Sciences (India)

Molecular assessment of genetic diversity in cluster bean. (Cyamopsis tetragonoloba) genotypes. Rakesh Pathak, S. K. Singh, Manjit Singh and A. Henry. J. Genet. 89, 243–246. Figure 1. RAPD profile of 1–16 Cyamopsis tetragonoloba genotypes amplified with arbitrary primer OPA-16. Figure 2. RAPD profile of 17–32 ...

Performance assessment of semiempirical molecular orbital methods in describing halogen bonding: quantum mechanical and quantum mechanical/molecular mechanical-molecular dynamics study.

Science.gov (United States)

Ibrahim, Mahmoud A A

2011-10-24

The performance of semiempirical molecular-orbital methods--MNDO, MNDO-d, AM1, RM1, PM3 and PM6--in describing halogen bonding was evaluated, and the results were compared with molecular mechanical (MM) and quantum mechanical (QM) data. Three types of performance were assessed: (1) geometrical optimizations and binding energy calculations for 27 halogen-containing molecules complexed with various Lewis bases (Two of the tested methods, AM1 and RM1, gave results that agree with the QM data.); (2) charge distribution calculations for halobenzene molecules, determined by calculating the solvation free energies of the molecules relative to benzene in explicit and implicit generalized Born (GB) solvents (None of the methods gave results that agree with the experimental data.); and (3) appropriateness of the semiempirical methods in the hybrid quantum-mechanical/molecular-mechanical (QM/MM) scheme, investigated by studying the molecular inhibition of CK2 protein by eight halobenzimidazole and -benzotriazole derivatives using hybrid QM/MM molecular-dynamics (MD) simulations with the inhibitor described at the QM level by the AM1 method and the rest of the system described at the MM level. The pure MM approach with inclusion of an extra point of positive charge on the halogen atom approach gave better results than the hybrid QM/MM approach involving the AM1 method. Also, in comparison with the pure MM-GBSA (generalized Born surface area) binding energies and experimental data, the calculated QM/MM-GBSA binding energies of the inhibitors were improved by replacing the G(GB,QM/MM) solvation term with the corresponding G(GB,MM) term.

[Malignant Melanoma - from Classical Histology towards Molecular Genetic Testing].

Science.gov (United States)

Ryška, A; Horký, O; Berkovcová, J; Tichá, I; Kalinová, M; Matějčková, M; Bóday, Á; Drábek, J; Martínek, P; Šimová, J; Sieglová, K; Vošmiková, H

Malignant melanoma is - in comparison with other skin tumors - a relatively rare malignant neoplasm with highly aggressive biologic behavior and variable prognosis. Recent data in pathology and molecular diagnostics indicate that malignant melanoma is in fact not a single entity but a group of different neoplasms with variable etiopathogenesis, biologic behavior and prognosis. New therapeutic options using targeted treatment blocking MAPK signaling pathway require testing of BRAF gene mutation status. This helps to select patients with highest probability of benefit from this treatment. This article summarizes information on the correlation of morphological findings with genetic changes, discusses the representation of individual genetic types in various morphological subgroups and deals with the newly proposed genetic classification of melanoma and the current possibilities, pitfalls and challenges in BRAF testing of malignant melanoma. It also describes the current testing situation in the Czech Republic - the methods used, the representation of BRAF mutations in the tested population and the future of testing. It also shows the limitations of the BRAF and MEK targeted treatment concept resulting from the heterogeneity of the tumor population. Mechanisms of acquired resistance to MAPK pathway inhibitors, possibilities of their detection, and issues of combination of targeted therapy and immunotherapy are discussed.Key words: malignant melanoma - BRAF - mutation - molecular targeted therapy - tumor microenvironment - tumor heterogeneity This work was supported by projects PROGRES Q40/11, BBMRICZ LM2015089, SVV 260398 and GACR 17-10331S. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 28. 3. 2017Accepted: 16. 5. 2017.

The molecular genetic architecture of self-employment.

Science.gov (United States)

van der Loos, Matthijs J H M; Rietveld, Cornelius A; Eklund, Niina; Koellinger, Philipp D; Rivadeneira, Fernando; Abecasis, Gonçalo R; Ankra-Badu, Georgina A; Baumeister, Sebastian E; Benjamin, Daniel J; Biffar, Reiner; Blankenberg, Stefan; Boomsma, Dorret I; Cesarini, David; Cucca, Francesco; de Geus, Eco J C; Dedoussis, George; Deloukas, Panos; Dimitriou, Maria; Eiriksdottir, Guðny; Eriksson, Johan; Gieger, Christian; Gudnason, Vilmundur; Höhne, Birgit; Holle, Rolf; Hottenga, Jouke-Jan; Isaacs, Aaron; Järvelin, Marjo-Riitta; Johannesson, Magnus; Kaakinen, Marika; Kähönen, Mika; Kanoni, Stavroula; Laaksonen, Maarit A; Lahti, Jari; Launer, Lenore J; Lehtimäki, Terho; Loitfelder, Marisa; Magnusson, Patrik K E; Naitza, Silvia; Oostra, Ben A; Perola, Markus; Petrovic, Katja; Quaye, Lydia; Raitakari, Olli; Ripatti, Samuli; Scheet, Paul; Schlessinger, David; Schmidt, Carsten O; Schmidt, Helena; Schmidt, Reinhold; Senft, Andrea; Smith, Albert V; Spector, Timothy D; Surakka, Ida; Svento, Rauli; Terracciano, Antonio; Tikkanen, Emmi; van Duijn, Cornelia M; Viikari, Jorma; Völzke, Henry; Wichmann, H-Erich; Wild, Philipp S; Willems, Sara M; Willemsen, Gonneke; van Rooij, Frank J A; Groenen, Patrick J F; Uitterlinden, André G; Hofman, Albert; Thurik, A Roy

2013-01-01

Economic variables such as income, education, and occupation are known to affect mortality and morbidity, such as cardiovascular disease, and have also been shown to be partly heritable. However, very little is known about which genes influence economic variables, although these genes may have both a direct and an indirect effect on health. We report results from the first large-scale collaboration that studies the molecular genetic architecture of an economic variable-entrepreneurship-that was operationalized using self-employment, a widely-available proxy. Our results suggest that common SNPs when considered jointly explain about half of the narrow-sense heritability of self-employment estimated in twin data (σ(g)(2)/σ(P)(2) = 25%, h(2) = 55%). However, a meta-analysis of genome-wide association studies across sixteen studies comprising 50,627 participants did not identify genome-wide significant SNPs. 58 SNPs with pself-employment in an independent sample (p≥0.039). Our results are consistent with a highly polygenic molecular genetic architecture of self-employment, with many genetic variants of small effect. Although self-employment is a multi-faceted, heavily environmentally influenced, and biologically distal trait, our results are similar to those for other genetically complex and biologically more proximate outcomes, such as height, intelligence, personality, and several diseases.

Molecular mechanisms of aging and immune system regulation in Drosophila.

Science.gov (United States)

Eleftherianos, Ioannis; Castillo, Julio Cesar

2012-01-01

Aging is a complex process that involves the accumulation of deleterious changes resulting in overall decline in several vital functions, leading to the progressive deterioration in physiological condition of the organism and eventually causing disease and death. The immune system is the most important host-defense mechanism in humans and is also highly conserved in insects. Extensive research in vertebrates has concluded that aging of the immune function results in increased susceptibility to infectious disease and chronic inflammation. Over the years, interest has grown in studying the molecular interaction between aging and the immune response to pathogenic infections. The fruit fly Drosophila melanogaster is an excellent model system for dissecting the genetic and genomic basis of important biological processes, such as aging and the innate immune system, and deciphering parallel mechanisms in vertebrate animals. Here, we review the recent advances in the identification of key players modulating the relationship between molecular aging networks and immune signal transduction pathways in the fly. Understanding the details of the molecular events involved in aging and immune system regulation will potentially lead to the development of strategies for decreasing the impact of age-related diseases, thus improving human health and life span.

Advances in molecular genetic studies of primary dystonia

Directory of Open Access Journals (Sweden)

MA Ling-yan

2013-07-01

Full Text Available Dystonias are heterogeneous hyperkinetic movement disorders characterized by involuntary muscle contractions which result in twisting, repetitive movements and abnormal postures. In recent years, there was a great advance in molecular genetic studies of primary dystonia. This paper will review the clinical characteristics and molecular genetic studies of primary dystonia, including early-onset generalized torsion dystonia (DYT1, whispering dysphonia (DYT4, dopa-responsive dystonia (DYT5, mixed-type dystonia (DYT6, paroxysmal kinesigenic dyskinesia (DYT10, myoclonus-dystonia syndrome (DYT11, rapid-onset dystonia parkinsonism (DYT12, adult-onset cervical dystonia (DYT23, craniocervical dystonia (DYT24 and primary torsion dystonia (DYT25.

Molecular Signature and Mechanisms of Hepatitis D Virus-Associated Hepatocellular Carcinoma.

Science.gov (United States)

Diaz, Giacomo; Engle, Ronald E; Tice, Ashley; Melis, Marta; Montenegro, Stephanie; Rodriguez-Canales, Jaime; Hanson, Jeffrey; Emmert-Buck, Michael R; Bock, Kevin W; Moore, Ian N; Zamboni, Fausto; Govindarajan, Sugantha; Kleiner, David; Farci, Patrizia

2018-06-01

There is limited data on the molecular mechanisms whereby hepatitis D virus (HDV) promotes liver cancer. Therefore, serum and liver specimens obtained at the time of liver transplantation from well-characterized patients with HDV-HCC (n-5) and with non-HCC HDV cirrhosis (n=7) were studied using an integrated genomic approach. Transcriptomic profiling was performed using laser capture-microdissected (LCM) malignant and non-malignant hepatocytes, tumorous and non-tumorous liver tissue from patients with HDV-HCC, and liver tissue from patients with non-HCC HDV cirrhosis. HDV-HCC was also compared with hepatitis B virus (HBV) HBV-HCC alone and hepatitis C virus (HCV) HCV-HCC. HDV malignant hepatocytes were characterized by an enrichment of up-regulated transcripts associated with pathways involved in cell cycle/DNA replication, damage and repair (sonic hedgehog, GADD45, DNA-damage-induced 14-3-3σ, cyclins and cell cycle regulation, cell cycle: G2/M DNA-damage checkpoint regulation, and hereditary breast cancer). Moreover, a large network of genes identified functionally relate to DNA repair, cell cycle, mitotic apparatus and cell division, including 4 cancer testis antigen genes, attesting to the critical role of genetic instability in this tumor. Besides being over-expressed, these genes were also strongly co-regulated. Gene co-regulation was high not only when compared to non-malignant hepatocytes, but also to malignant hepatocytes from HBV-HCC alone or HCV-HCC. Activation and co-regulation of genes critically associated with DNA replication, damage, and repair point to genetic instability as an important mechanism of HDV hepatocarcinogenesis. This specific HDV-HCC trait emerged also from the comparison of the molecular pathways identified for each hepatitis virus-associated HCC. Despite the dependence of HDV on HBV, these findings suggest that HDV and HBV promote carcinogenesis by distinct molecular mechanisms. This study identifies a molecular signature of HDV

The Molecular Genetic Architecture of Self-Employment

Science.gov (United States)

van der Loos, Matthijs J. H. M.; Rietveld, Cornelius A.; Eklund, Niina; Koellinger, Philipp D.; Rivadeneira, Fernando; Abecasis, Gonçalo R.; Ankra-Badu, Georgina A.; Baumeister, Sebastian E.; Benjamin, Daniel J.; Biffar, Reiner; Blankenberg, Stefan; Boomsma, Dorret I.; Cesarini, David; Cucca, Francesco; de Geus, Eco J. C.; Dedoussis, George; Deloukas, Panos; Dimitriou, Maria; Eiriksdottir, Guðny; Eriksson, Johan; Gieger, Christian; Gudnason, Vilmundur; Höhne, Birgit; Holle, Rolf; Hottenga, Jouke-Jan; Isaacs, Aaron; Järvelin, Marjo-Riitta; Johannesson, Magnus; Kaakinen, Marika; Kähönen, Mika; Kanoni, Stavroula; Laaksonen, Maarit A.; Lahti, Jari; Launer, Lenore J.; Lehtimäki, Terho; Loitfelder, Marisa; Magnusson, Patrik K. E.; Naitza, Silvia; Oostra, Ben A.; Perola, Markus; Petrovic, Katja; Quaye, Lydia; Raitakari, Olli; Ripatti, Samuli; Scheet, Paul; Schlessinger, David; Schmidt, Carsten O.; Schmidt, Helena; Schmidt, Reinhold; Senft, Andrea; Smith, Albert V.; Spector, Timothy D.; Surakka, Ida; Svento, Rauli; Terracciano, Antonio; Tikkanen, Emmi; van Duijn, Cornelia M.; Viikari, Jorma; Völzke, Henry; Wichmann, H. -Erich; Wild, Philipp S.; Willems, Sara M.; Willemsen, Gonneke; van Rooij, Frank J. A.; Groenen, Patrick J. F.; Uitterlinden, André G.; Hofman, Albert; Thurik, A. Roy

2013-01-01

Economic variables such as income, education, and occupation are known to affect mortality and morbidity, such as cardiovascular disease, and have also been shown to be partly heritable. However, very little is known about which genes influence economic variables, although these genes may have both a direct and an indirect effect on health. We report results from the first large-scale collaboration that studies the molecular genetic architecture of an economic variable–entrepreneurship–that was operationalized using self-employment, a widely-available proxy. Our results suggest that common SNPs when considered jointly explain about half of the narrow-sense heritability of self-employment estimated in twin data (σg 2/σP 2 = 25%, h 2 = 55%). However, a meta-analysis of genome-wide association studies across sixteen studies comprising 50,627 participants did not identify genome-wide significant SNPs. 58 SNPs with pentrepreneurship reveal significant associations. Finally, SNP-based genetic scores that use results from the meta-analysis capture less than 0.2% of the variance in self-employment in an independent sample (p≥0.039). Our results are consistent with a highly polygenic molecular genetic architecture of self-employment, with many genetic variants of small effect. Although self-employment is a multi-faceted, heavily environmentally influenced, and biologically distal trait, our results are similar to those for other genetically complex and biologically more proximate outcomes, such as height, intelligence, personality, and several diseases. PMID:23593239

Quantum Mechanics/Molecular Mechanics Free Energy Maps and Nonadiabatic Simulations for a Photochemical Reaction in DNA: Cyclobutane Thymine Dimer.

Science.gov (United States)

Mendieta-Moreno, Jesús I; Trabada, Daniel G; Mendieta, Jesús; Lewis, James P; Gómez-Puertas, Paulino; Ortega, José

2016-11-03

The absorption of ultraviolet radiation by DNA may result in harmful genetic lesions that affect DNA replication and transcription, ultimately causing mutations, cancer, and/or cell death. We analyze the most abundant photochemical reaction in DNA, the cyclobutane thymine dimer, using hybrid quantum mechanics/molecular mechanics (QM/MM) techniques and QM/MM nonadiabatic molecular dynamics. We find that, due to its double helix structure, DNA presents a free energy barrier between nonreactive and reactive conformations leading to the photolesion. Moreover, our nonadiabatic simulations show that most of the photoexcited reactive conformations return to standard B-DNA conformations after an ultrafast nonradiative decay to the ground state. This work highlights the importance of dynamical effects (free energy, excited-state dynamics) for the study of photochemical reactions in biological systems.

Sampling Molecular Conformers in Solution with Quantum Mechanical Accuracy at a Nearly Molecular-Mechanics Cost.

Science.gov (United States)

Rosa, Marta; Micciarelli, Marco; Laio, Alessandro; Baroni, Stefano

2016-09-13

We introduce a method to evaluate the relative populations of different conformers of molecular species in solution, aiming at quantum mechanical accuracy, while keeping the computational cost at a nearly molecular-mechanics level. This goal is achieved by combining long classical molecular-dynamics simulations to sample the free-energy landscape of the system, advanced clustering techniques to identify the most relevant conformers, and thermodynamic perturbation theory to correct the resulting populations, using quantum-mechanical energies from density functional theory. A quantitative criterion for assessing the accuracy thus achieved is proposed. The resulting methodology is demonstrated in the specific case of cyanin (cyanidin-3-glucoside) in water solution.

Molecular mechanisms of carcinogenesis

International Nuclear Information System (INIS)

Hall, E.J.

1997-01-01

The possibility that chromosomal changes are responsible for neoplasia was proposed in the early years of this century. A combination of improved cytogenetics and the advent of recombinant technology has settled the issue. As recently as 20 years ago, however, the genetic and molecular basis of familiar predisposition to cancer were a mystery, and it is only in the last few years that light has been shed on a few specific types of malignancies. As the genetic basis of human cancer had been documented, a number of genes have been identified as functioning either as oncogenes which act in a dominant fashion to promote tumor growth when mutated, or as tumor suppressor genes which act in a recessive fashion

Molecular genetics of aging in the fly: is this the end of the beginning?

Science.gov (United States)

Helfand, Stephen L; Rogina, Blanka

2003-02-01

How we age and what we can do about it have been uppermost in human thought since antiquity. The many false starts have frustrated experimentalists and theoretical arguments pronouncing the inevitability of the process have created a nihilistic climate among scientists and the public. The identification of single gene alterations that substantially extend life span in nematodes and flies however, have begun to reinvigorate the field. Drosophila's long history of contributions to aging research, rich storehouse of genetic information, and powerful molecular techniques make it an excellent system for studying the molecular mechanisms underlying the process of aging. In recent years, Drosophila has been used to test current theories on aging and explore new directions of potential importance to the biology of aging. One such example is the surprising finding that, as opposed to the commonly held assumption that adult life is a period of random passive decline in which all things are thought to fall apart, the molecular life of the adult fly appears to be a state of dynamic well-regulated change. In the fly, the level of expression of many different genes changes in an invariant, often age-dependent, manner. These as well as other molecular genetic studies and demographic analyses using the fly have begun to challenge widely held ideas about aging providing evidence that aging may be a much more dynamic and malleable process than anticipated. With the enormous success that Drosophila molecular genetics has demonstrated in helping understand complex biological phenomena such as development there is much optimism that similar approaches can be adapted to assist in understanding the process of aging. Copyright 2003 Wiley Periodicals, Inc.

Molecular Mechanisms of DNA Replication Checkpoint Activation

Directory of Open Access Journals (Sweden)

Bénédicte Recolin

2014-03-01

Full Text Available The major challenge of the cell cycle is to deliver an intact, and fully duplicated, genetic material to the daughter cells. To this end, progression of DNA synthesis is monitored by a feedback mechanism known as replication checkpoint that is untimely linked to DNA replication. This signaling pathway ensures coordination of DNA synthesis with cell cycle progression. Failure to activate this checkpoint in response to perturbation of DNA synthesis (replication stress results in forced cell division leading to chromosome fragmentation, aneuploidy, and genomic instability. In this review, we will describe current knowledge of the molecular determinants of the DNA replication checkpoint in eukaryotic cells and discuss a model of activation of this signaling pathway crucial for maintenance of genomic stability.

The molecular mechanism and physiological role of cytoplasmic streaming.

Science.gov (United States)

Tominaga, Motoki; Ito, Kohji

2015-10-01

Cytoplasmic streaming occurs widely in plants ranging from algae to angiosperms. However, the molecular mechanism and physiological role of cytoplasmic streaming have long remained unelucidated. Recent molecular genetic approaches have identified specific myosin members (XI-2 and XI-K as major and XI-1, XI-B, and XI-I as minor motive forces) for the generation of cytoplasmic streaming among 13 myosin XIs in Arabidopsis thaliana. Simultaneous knockout of these myosin XI members led to a reduced velocity of cytoplasmic streaming and marked defects of plant development. Furthermore, the artificial modifications of myosin XI-2 velocity changed plant and cell sizes along with the velocity of cytoplasmic streaming. Therefore, we assume that cytoplasmic streaming is one of the key regulators in determining plant size. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Molecular Mechanism of Somite Development

Directory of Open Access Journals (Sweden)

Gulfidan Coskun

2013-06-01

Full Text Available From third week of gestation, notochord and the neural folds begin to gather at the center of the embryo to form the paraxial mesoderm. Paraxial mesoderm separates into blocks of cells called somitomers at the lateral sides of the neural tube of the head region. At the beginning of the third week somitomeres take ring shapes and form blocks of somites from occipital region to caudal region. Although somites are transient structures, they are extremely important in organizing the segmental pattern of vertebrate embryos. Somites give rise to the cells that form the vertebrae and ribs, the dermis of the dorsal skin, the skeletal muscles of the back, and the skeletal muscles of the body wall and limbs. Somitogenesis are formed by a genetic mechanism that is regulated by cyclical expression of genes in the Notch, Wnt and fibroblast growth factor signaling pathways. The prevailing model of the mechanism governing somitogenesis is the “clock and wave front”. Somitogenesis has components of periodicity, separation, epithelialization and axial specification. According to this model, the clock causes cells to undergo repeated oscillations, with a particular phase of each oscillation defining the competency of cells in the presomitic mesoderm to form a somite. Any disruption in this mechanism can be cause of severe segmentation defects of the vertebrae and congenital anomalies. In this review, we discuss the molecular mechanisms underlying the somitogenesis which is an important part of morphogenesis. [Archives Medical Review Journal 2013; 22(3.000: 362-376

Drugs meeting the molecular basis of diabetic kidney disease: bridging from molecular mechanism to personalized medicine.

Science.gov (United States)

Lambers Heerspink, Hiddo J; Oberbauer, Rainer; Perco, Paul; Heinzel, Andreas; Heinze, Georg; Mayer, Gert; Mayer, Bernd

2015-08-01

Diabetic kidney disease (DKD) is a complex, multifactorial disease and is associated with a high risk of renal and cardiovascular morbidity and mortality. Clinical practice guidelines for diabetes recommend essentially identical treatments for all patients without taking into account how the individual responds to the instituted therapy. Yet, individuals vary widely in how they respond to medications and therefore optimal therapy differs between individuals. Understanding the underlying molecular mechanisms of variability in drug response will help tailor optimal therapy. Polymorphisms in genes related to drug pharmacokinetics have been used to explore mechanisms of response variability in DKD, but with limited success. The complex interaction between genetic make-up and environmental factors on the abundance of proteins and metabolites renders pharmacogenomics alone insufficient to fully capture response variability. A complementary approach is to attribute drug response variability to individual variability in underlying molecular mechanisms involved in the progression of disease. The interplay of different processes (e.g. inflammation, fibrosis, angiogenesis, oxidative stress) appears to drive disease progression, but the individual contribution of each process varies. Drugs at the other hand address specific targets and thereby interfere in certain disease-associated processes. At this level, biomarkers may help to gain insight into which specific pathophysiological processes are involved in an individual followed by a rational assessment whether a specific drug's mode of action indeed targets the relevant process at hand. This article describes the conceptual background and data-driven workflow developed by the SysKid consortium aimed at improving characterization of the molecular mechanisms underlying DKD at the interference of the molecular impact of individual drugs in order to tailor optimal therapy to individual patients. © The Author 2015. Published by

Molecular Mechanisms of Bacterial Pathogenicity

Science.gov (United States)

Fuchs, Thilo Martin

Cautious optimism has arisen over recent decades with respect to the long struggle against bacteria, viruses, and parasites. This has been offset, however, by a fatal complacency stemming from previous successes such as the development of antimicrobial drugs, the eradication of smallpox, and global immunization programs. Infectious diseases nevertheless remain the world's leading cause of death, killing at least 17 million persons annually [61]. Diarrheal diseases caused by Vibrio cholerae or Shigella dysenteriae kill about 3 million persons every year, most of them young children: Another 4 million die of tuberculosis or tetanus. Outbreaks of diphtheria in Eastern Europe threatens the population with a disease that had previously seemed to be overcome. Efforts to control infectious diseases more comprehensively are undermined not only by socioeconomic conditions but also by the nature of the pathogenic organisms itself; some isolates of Staphylococcus aureus and Enterobacter have become so resistant to drugs by horizontal gene transfer that they are almost untreatable. In addition, the mechanism of genetic variability helps pathogens to evade the human immune system, thus compromising the development of powerful vaccines. Therefore detailed knowledge of the molecular mechanisms of microbial pathogenicity is absolutely necessary to develop new strategies against infectious diseases and thus to lower their impact on human health and social development.

Abundant genetic overlap between blood lipids and immune-mediated diseases indicates shared molecular genetic mechanisms.

Directory of Open Access Journals (Sweden)

Ole A Andreassen

Full Text Available Epidemiological studies suggest a relationship between blood lipids and immune-mediated diseases, but the nature of these associations is not well understood. We used genome-wide association studies (GWAS to investigate shared single nucleotide polymorphisms (SNPs between blood lipids and immune-mediated diseases. We analyzed data from GWAS (n~200,000 individuals, applying new False Discovery Rate (FDR methods, to investigate genetic overlap between blood lipid levels [triglycerides (TG, low density lipoproteins (LDL, high density lipoproteins (HDL] and a selection of archetypal immune-mediated diseases (Crohn's disease, ulcerative colitis, rheumatoid arthritis, type 1 diabetes, celiac disease, psoriasis and sarcoidosis. We found significant polygenic pleiotropy between the blood lipids and all the investigated immune-mediated diseases. We discovered several shared risk loci between the immune-mediated diseases and TG (n = 88, LDL (n = 87 and HDL (n = 52. Three-way analyses differentiated the pattern of pleiotropy among the immune-mediated diseases. The new pleiotropic loci increased the number of functional gene network nodes representing blood lipid loci by 40%. Pathway analyses implicated several novel shared mechanisms for immune pathogenesis and lipid biology, including glycosphingolipid synthesis (e.g. FUT2 and intestinal host-microbe interactions (e.g. ATG16L1. We demonstrate a shared genetic basis for blood lipids and immune-mediated diseases independent of environmental factors. Our findings provide novel mechanistic insights into dyslipidemia and immune-mediated diseases and may have implications for therapeutic trials involving lipid-lowering and anti-inflammatory agents.

Genetic diversity of popcorn genotypes using molecular analysis.

Science.gov (United States)

Resh, F S; Scapim, C A; Mangolin, C A; Machado, M F P S; do Amaral, A T; Ramos, H C C; Vivas, M

2015-08-19

In this study, we analyzed dominant molecular markers to estimate the genetic divergence of 26 popcorn genotypes and evaluate whether using various dissimilarity coefficients with these dominant markers influences the results of cluster analysis. Fifteen random amplification of polymorphic DNA primers produced 157 amplified fragments, of which 65 were monomorphic and 92 were polymorphic. To calculate the genetic distances among the 26 genotypes, the complements of the Jaccard, Dice, and Rogers and Tanimoto similarity coefficients were used. A matrix of Dij values (dissimilarity matrix) was constructed, from which the genetic distances among genotypes were represented in a more simplified manner as a dendrogram generated using the unweighted pair-group method with arithmetic average. Clusters determined by molecular analysis generally did not group material from the same parental origin together. The largest genetic distance was between varieties 17 (UNB-2) and 18 (PA-091). In the identification of genotypes with the smallest genetic distance, the 3 coefficients showed no agreement. The 3 dissimilarity coefficients showed no major differences among their grouping patterns because agreement in determining the genotypes with large, medium, and small genetic distances was high. The largest genetic distances were observed for the Rogers and Tanimoto dissimilarity coefficient (0.74), followed by the Jaccard coefficient (0.65) and the Dice coefficient (0.48). The 3 coefficients showed similar estimations for the cophenetic correlation coefficient. Correlations among the matrices generated using the 3 coefficients were positive and had high magnitudes, reflecting strong agreement among the results obtained using the 3 evaluated dissimilarity coefficients.

Molecular evaluation of genetic diversity and association studies in ...

Indian Academy of Sciences (India)

Molecular evaluation of genetic diversity and association studies in rice. (Oryza sativa L.) C. Vanniarajan, K. K. Vinod and Andy Pereira. J. Genet. 91, 9–19. Table 1. Chromosome-wise distribution of SSR alleles and their number (k), polymorphic information content (PIC) and allele discrimination index (Dm). Chromosome.

Empirical Refinements of a Molecular Genetics Learning Progression: The Molecular Constructs

Science.gov (United States)

Todd, Amber; Kenyon, Lisa

2016-01-01

This article describes revisions to four of the eight constructs of the Duncan molecular genetics learning progression [Duncan, Rogat, & Yarden, (2009)]. As learning progressions remain hypothetical models until validated by multiple rounds of empirical studies, these revisions are an important step toward validating the progression. Our…

Primer on molecular genetics. DOE Human Genome Program

Energy Technology Data Exchange (ETDEWEB)

1992-04-01

This report is taken from the April 1992 draft of the DOE Human Genome 1991--1992 Program Report, which is expected to be published in May 1992. The primer is intended to be an introduction to basic principles of molecular genetics pertaining to the genome project. The material contained herein is not final and may be incomplete. Techniques of genetic mapping and DNA sequencing are described.

EMQN/CMGS best practice guidelines for the molecular genetic testing of Huntington disease.

Science.gov (United States)

Losekoot, Monique; van Belzen, Martine J; Seneca, Sara; Bauer, Peter; Stenhouse, Susan A R; Barton, David E

2013-05-01

Huntington disease (HD) is caused by the expansion of an unstable polymorphic trinucleotide (CAG)n repeat in exon 1 of the HTT gene, which translates into an extended polyglutamine tract in the protein. Laboratory diagnosis of HD involves estimation of the number of CAG repeats. Molecular genetic testing for HD is offered in a wide range of laboratories both within and outside the European community. In order to measure the quality and raise the standard of molecular genetic testing in these laboratories, the European Molecular Genetics Quality Network has organized a yearly external quality assessment (EQA) scheme for molecular genetic testing of HD for over 10 years. EQA compares a laboratory's output with a fixed standard both for genotyping and reporting of the results to the referring physicians. In general, the standard of genotyping is very high but the clarity of interpretation and reporting of the test result varies more widely. This emphasizes the need for best practice guidelines for this disorder. We have therefore developed these best practice guidelines for genetic testing for HD to assist in testing and reporting of results. The analytical methods and the potential pitfalls of molecular genetic testing are highlighted and the implications of the different test outcomes for the consultand and his or her family members are discussed.

Quantum Mechanics/Molecular Mechanics Modeling of Drug Metabolism

DEFF Research Database (Denmark)

Lonsdale, Richard; Fort, Rachel M; Rydberg, Patrik

2016-01-01

)-mexiletine in CYP1A2 with hybrid quantum mechanics/molecular mechanics (QM/MM) methods, providing a more detailed and realistic model. Multiple reaction barriers have been calculated at the QM(B3LYP-D)/MM(CHARMM27) level for the direct N-oxidation and H-abstraction/rebound mechanisms. Our calculated barriers......The mechanism of cytochrome P450(CYP)-catalyzed hydroxylation of primary amines is currently unclear and is relevant to drug metabolism; previous small model calculations have suggested two possible mechanisms: direct N-oxidation and H-abstraction/rebound. We have modeled the N-hydroxylation of (R...... indicate that the direct N-oxidation mechanism is preferred and proceeds via the doublet spin state of Compound I. Molecular dynamics simulations indicate that the presence of an ordered water molecule in the active site assists in the binding of mexiletine in the active site...

Medulloblastoma: Molecular Genetics and Animal Models

Directory of Open Access Journals (Sweden)

Corey Raffel

2004-07-01

Full Text Available Medulloblastoma is a primary brain tumor found in the cerebellum of children. The tumor occurs in association with two inherited cancer syndromes: Turcot syndrome and Gorlin syndrome. Insights into the molecular biology of the tumor have come from looking at alterations in the genes altered in these syndromes, PTC and APC, respectively. Murine models of medulloblastoma have been constructed based on these alterations. Additional murine models that, while mimicking the appearance of the human tumor, seem unrelated to the human tumor's molecular alterations have been made. In this review, the clinical picture, origin, molecular biology, murine models of medulloblastoma are discussed. Although a great deal has been discovered about this tumor, the genetic alterations responsible for tumor development in a majority of patients have yet to be described.

Molecular Mechanisms of Cutaneous Inflammatory Disorder: Atopic Dermatitis

Science.gov (United States)

Kim, Jung Eun; Kim, Jong Sic; Cho, Dae Ho; Park, Hyun Jeong

2016-01-01

Atopic dermatitis (AD) is a multifactorial inflammatory skin disease resulting from interactions between genetic susceptibility and environmental factors. The pathogenesis of AD is poorly understood, and the treatment of recalcitrant AD is still challenging. There is accumulating evidence for new gene polymorphisms related to the epidermal barrier function and innate and adaptive immunity in patients with AD. Newly-found T cells and dendritic cell subsets, cytokines, chemokines and signaling pathways have extended our understanding of the molecular pathomechanism underlying AD. Genetic changes caused by environmental factors have been shown to contribute to the pathogenesis of AD. We herein present a review of the genetics, epigenetics, barrier dysfunction and immunological abnormalities in AD with a focus on updated molecular biology. PMID:27483258

Molecular Mechanism of Gastric Carcinogenesis in Helicobacter pylori-Infected Rodent Models

Directory of Open Access Journals (Sweden)

Takeshi Toyoda

2014-06-01

Full Text Available Since the discovery of Helicobacter pylori (H. pylori, many efforts have been made to establish animal models for the investigation of the pathological features and molecular mechanisms of gastric carcinogenesis. Among the animal models, Mongolian gerbils and mice are particularly useful for the analysis of H. pylori-associated inflammatory reactions and gastric cancer development. Inhibitors of oxidative stress, cyclooxygenase-2 (COX-2 and nuclear factor-κB, exert preventive effects on chronic gastritis and the development of adenocarcinomas in H. pylori-infected gerbils. Genetically-modified mouse models, including transgenic and knockout mice, have also revealed the importance of p53, COX-2/prostaglandin, Wnt/β-catenin, proinflammatory cytokines, gastrin and type III mucin in the molecular mechanisms of gastric carcinogenesis. Microarray technology is available for comprehensive gene analysis in the gastric mucosa of mouse models, and epigenetics, such as DNA methylation, could be an alternative approach to correlate the observations in animal models with the etiology in humans.

Genetic and molecular analysis of radon-induced rat lung tumours

International Nuclear Information System (INIS)

Guilly, M.N.; Joubert, Ch.; Levalois, C.; Dano, L.; Chevillard, S.

2002-01-01

We have a model of radon-induced rat lung tumours, which allow us to analyse the cytogenetic and molecular alterations of the tumours. The aim is to better understand the mechanisms of radio-induced carcinogenesis and to define if it exists a specificity of radio-induced genetic alterations as compared to the genetic alterations found in the sporadic tumours. We have started our analysis by developing global cytogenetic and molecular approaches. We have shown that some alterations are recurrent. The genes that are potentially involved are the oncogene MET and the tumour suppressor Bene p16, which are also frequently altered in human lung tumours. Simultaneously, we have focussed our analysis by targeting the search of mutation in the tumour suppressor gene TP3. We have found that 8 of 39 tumours were mutated by deletion in the coding sequence of TP53. This high frequency of deletion, which is not observed in the human p53 mutation database could constitute a signature of radio-induced alterations. On this assumption, this type of alteration should not be only found on TP53 Bene but also in other suppressor genes which are inactivated by a mutation such as p16 for example. The work we are carrying out on radio-induced tumours among humans and animals is directed to this end. (author)

Polarization effects in molecular mechanical force fields

Energy Technology Data Exchange (ETDEWEB)

Cieplak, Piotr [Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92120 (United States); Dupradeau, Francois-Yves [UMR CNRS 6219-Faculte de Pharmacie, Universite de Picardie Jules Verne, 1 rue des Louvels, F-80037 Amiens (France); Duan, Yong [Genome Center and Department of Applied Science, University of California, Davis, One Shields Avenue, Davis, CA 95616 (United States); Wang Junmei, E-mail: pcieplak@burnham.or [Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park Boulevard, ND9.136, Dallas, TX 75390-9050 (United States)

2009-08-19

The focus here is on incorporating electronic polarization into classical molecular mechanical force fields used for macromolecular simulations. First, we briefly examine currently used molecular mechanical force fields and the current status of intermolecular forces as viewed by quantum mechanical approaches. Next, we demonstrate how some components of quantum mechanical energy are effectively incorporated into classical molecular mechanical force fields. Finally, we assess the modeling methods of one such energy component-polarization energy-and present an overview of polarizable force fields and their current applications. Incorporating polarization effects into current force fields paves the way to developing potentially more accurate, though more complex, parameterizations that can be used for more realistic molecular simulations. (topical review)

A molecular genetic toolbox for Yarrowia lipolytica

DEFF Research Database (Denmark)

Bredeweg, Erin L.; Pomraning, Kyle R.; Dai, Ziyu

2017-01-01

used these tools to build the "Yarrowia lipolytica Cell Atlas," a collection of strains with endogenous fluorescently tagged organelles in the same genetic background, in order to define organelle morphology in live cells. Conclusions: These molecular and isogenetic tools are useful for live assessment...

DataGenno: building a new tool to bridge molecular and clinical genetics

Directory of Open Access Journals (Sweden)

Fabricio F Costa

2011-03-01

Full Text Available Fabricio F Costa1,2, Luciano S Foly1, Marcelo P Coutinho11DataGenno Interactive Research Ltd., Itaperuna, Rio de Janeiro, Brazil; 2Cancer Biology and Epigenomics Program, Children's Memorial Research Center, Northwestern University's Feinberg School of Medicine, Chicago, IL, USAAbstract: Clinical genetics is one of the most challenging fields in medicine, with thousands of children born every year with congenital defects that have no satisfactory diagnosis. There are more than 6,000 known single-gene disorders that can cause birth defects or diseases in approximately 1 in every 200 births. Clinical and molecular information on genetic diseases and syndromes are widespread in the literature, and there are few databases combining this information. Therefore, it is very challenging for health care professionals and researchers to translate the latest advances in science and medicine into effective clinical interventions and new treatments. In order to overcome this obstacle and promote networking, we are building DataGenno, an online medical and scientific portal. DataGenno has been developed to be a source of information on genetic diseases and syndromes for the needs of all heath care professionals and researchers. Our database will be able to integrate both clinical and molecular aspects of genetic diseases in a fully interactive environment. DataGenno’s system already contains clinical and molecular information for 300 diseases, with approximately 6,000 signs and symptoms of these diseases in a database combined with a search engine. Our main goal is to cover all genetic diseases described to date, providing not only clinical information such as morphological and anatomical features but also the most comprehensive molecular genetics/genomics features and available testing information. We are also developing ways to connect DataGenno’s portal with Electronic Health Records in order to improve the efficiency of patient care. Additionally

Genetic variability of hull-less barley accessions based on molecular and quantitative data

Directory of Open Access Journals (Sweden)

Ricardo Meneses Sayd

2015-02-01

Full Text Available The objective of this work was to characterize and quantify the genetic, molecular, and agronomic variability of hull-less barley genotypes, for the selection of parents and identification of genotypes adapted to the irrigated production system in the Brazilian Cerrado. Eighteen hull-less barley accessions were evaluated, and three covered barley accessions served as reference. The characterization was based on 157 RAPD molecular markers and ten agronomic traits. Genetic distance matrices were obtained based on molecular markers and quantitative traits. Graphic grouping and dispersion analyses were performed. Genetic, molecular, and agronomic variability was high among genotypes. Ethiopian accessions were genetically more similar, and the Brazilian ones were genetically more distant. For agronomic traits, two more consistent groupings were obtained, one with the most two-rowed materials, and the other with six-rowed materials. The more diverging materials were the two-rowed CI 13453, CN Cerrado 5, CN Cerrado 1, and CN Cerrado 2. The PI 356466, CN Cerrado 1, PI 370799, and CI 13453 genotypes show agronomic traits of interest and, as genetically different genotypes, they are indicated for crossing, in breeding programs.

Molecular genetics of pancreatic neoplasms and their morphologic correlates: an update on recent advances and potential diagnostic applications.

Science.gov (United States)

Reid, Michelle D; Saka, Burcu; Balci, Serdar; Goldblum, Andrew S; Adsay, N Volkan

2014-02-01

To summarize the most clinically and biologically relevant advances in molecular/genetic characteristics of various pancreatic neoplasms, with morphologic correlation. Whole-exome sequencing of numerous benign and malignant pancreatic tumors, along with the plethora of highly sensitive molecular studies now available for analyzing these tumors, provide mounting evidence to support the long-held belief that cancer is essentially a genetic disease. These genetic discoveries have not only helped to confirm the age-old, morphology-based classifications of pancreatic neoplasia but have shed new light on their mechanisms. Many of these molecular discoveries are currently being used in preoperative diagnosis. Mutations in KRAS, P16/CDKN2A, TP53, and SMAD4/DPC4 are commonly seen in ductal neoplasia but not in nonductal tumors; ductal adenocarcinomas with SMAD4/DPC4 loss are associated with widespread metastasis and poor prognosis. GNAS and RNF43 mutations have been discovered in most intraductal pancreatic mucinous neoplasms, providing critical molecular fingerprints for their diagnosis. Mutation in DAXX/ATRX is only seen in pancreatic neuroendocrine tumors, making it a useful potential marker in distinguishing these tumors from mimics. When combined with morphologic observations, molecular studies will increase our understanding of the pathogenesis and morphomolecular signatures associated with specific neoplasms and provide new horizons for precision medicine and targeted therapies.

Phenotypic and molecular genetic analysis of Pyruvate Kinase ...

African Journals Online (AJOL)

Phenotypic and molecular genetic analysis of Pyruvate Kinase deficiency in a Tunisian family. Jaouani Mouna, Hamdi Nadia, Chaouch Leila, Kalai Miniar, Mellouli Fethi, Darragi Imen, Boudriga Imen, Chaouachi Dorra, Bejaoui Mohamed, Abbes Salem ...

Quantum mechanics/coarse-grained molecular mechanics (QM/CG-MM).

Science.gov (United States)

Sinitskiy, Anton V; Voth, Gregory A

2018-01-07

Numerous molecular systems, including solutions, proteins, and composite materials, can be modeled using mixed-resolution representations, of which the quantum mechanics/molecular mechanics (QM/MM) approach has become the most widely used. However, the QM/MM approach often faces a number of challenges, including the high cost of repetitive QM computations, the slow sampling even for the MM part in those cases where a system under investigation has a complex dynamics, and a difficulty in providing a simple, qualitative interpretation of numerical results in terms of the influence of the molecular environment upon the active QM region. In this paper, we address these issues by combining QM/MM modeling with the methodology of "bottom-up" coarse-graining (CG) to provide the theoretical basis for a systematic quantum-mechanical/coarse-grained molecular mechanics (QM/CG-MM) mixed resolution approach. A derivation of the method is presented based on a combination of statistical mechanics and quantum mechanics, leading to an equation for the effective Hamiltonian of the QM part, a central concept in the QM/CG-MM theory. A detailed analysis of different contributions to the effective Hamiltonian from electrostatic, induction, dispersion, and exchange interactions between the QM part and the surroundings is provided, serving as a foundation for a potential hierarchy of QM/CG-MM methods varying in their accuracy and computational cost. A relationship of the QM/CG-MM methodology to other mixed resolution approaches is also discussed.

Quantum mechanics/coarse-grained molecular mechanics (QM/CG-MM)

Science.gov (United States)

Sinitskiy, Anton V.; Voth, Gregory A.

2018-01-01

Numerous molecular systems, including solutions, proteins, and composite materials, can be modeled using mixed-resolution representations, of which the quantum mechanics/molecular mechanics (QM/MM) approach has become the most widely used. However, the QM/MM approach often faces a number of challenges, including the high cost of repetitive QM computations, the slow sampling even for the MM part in those cases where a system under investigation has a complex dynamics, and a difficulty in providing a simple, qualitative interpretation of numerical results in terms of the influence of the molecular environment upon the active QM region. In this paper, we address these issues by combining QM/MM modeling with the methodology of "bottom-up" coarse-graining (CG) to provide the theoretical basis for a systematic quantum-mechanical/coarse-grained molecular mechanics (QM/CG-MM) mixed resolution approach. A derivation of the method is presented based on a combination of statistical mechanics and quantum mechanics, leading to an equation for the effective Hamiltonian of the QM part, a central concept in the QM/CG-MM theory. A detailed analysis of different contributions to the effective Hamiltonian from electrostatic, induction, dispersion, and exchange interactions between the QM part and the surroundings is provided, serving as a foundation for a potential hierarchy of QM/CG-MM methods varying in their accuracy and computational cost. A relationship of the QM/CG-MM methodology to other mixed resolution approaches is also discussed.

Use of molecular genetics and historical records to reconstruct the ...

African Journals Online (AJOL)

Recent advances in molecular genetics made the inference of past demographic events through the analysis of gene pools from modern populations possible. The technology uses genetic markers to provide previously unavailable resolution into questions of human evolution, migration and the historical relationship of ...

Molecular genetics

International Nuclear Information System (INIS)

Kubitschek, H.E.

1975-01-01

Progress is reported on studies on the nature and action of lethal and mutagenic lesions in DNA and the mechanisms by which these are produced in bacteria by ionizing radiation or by decay of radioisotopes incorporated in DNA. Studies of radioisotope decay provide the advantages that the original lesion is localized in the genetic material and the immediate physical and chemical changes that occur at decay are known. Specific types of DNA damage were related to characteristic decay properties of several radioisotopes. Incorporated 125 I, for example, induces a double-stranded break in DNA with almost every decay, but causes remarkably little damage of any other kind to the DNA. (U.S.)

Molecular species identification and population genetics of ...

African Journals Online (AJOL)

Molecular genetic techniques, such as DNA barcoding and genotyping, are increasingly being used to assist with the conservation and management of chondrichthyans worldwide. Southern Africa is a shark biodiversity hotspot, with a large number of endemic species. According to the IUCN Red List, a quarter of South ...

Molecular diversity and genetic relationships in Secale

Indian Academy of Sciences (India)

The objective of this study was to quantify the molecular diversity and to determine the genetic relationships amongSecalespp. and among cultivars ofSecale ... Faculty of Sciences, Campo Grande, Lisboa, Portugal; Departamento de Genética, Facultad de Biologia, Universidad Complutense, C/ José Antonio Novais, 12, ...

Molecular Genetic of Atopic dermatitis: An Update

Science.gov (United States)

Al-Shobaili, Hani A.; Ahmed, Ahmed A.; Alnomair, Naief; Alobead, Zeiad Abdulaziz; Rasheed, Zafar

2016-01-01

Atopic dermatitis (AD) is a chronic multifactorial inflammatory skin disease. The pathogenesis of AD remains unclear, but the disease results from dysfunctions of skin barrier and immune response, where both genetic and environmental factors play a key role. Recent studies demonstrate the substantial evidences that show a strong genetic association with AD. As for example, AD patients have a positive family history and have a concordance rate in twins. Moreover, several candidate genes have now been suspected that play a central role in the genetic background of AD. In last decade advanced procedures similar to genome-wide association (GWA) and single nucleotide polymorphism (SNP) have been applied on different population and now it has been clarified that AD is significantly associated with genes of innate/adaptive immune systems, human leukocyte antigens (HLA), cytokines, chemokines, drug-metabolizing genes or various other genes. In this review, we will highlight the recent advancements in the molecular genetics of AD, especially on possible functional relevance of genetic variants discovered to date. PMID:27004062

Molecular markers unravel intraspecific and interspecific genetic ...

Indian Academy of Sciences (India)

[Kotwal S., Dhar M. K., Kour B., Raj K. and Kaul S. 2013 Molecular markers unravel intraspecific and interspecific genetic variability in ... of bowel problems including chronic constipation, amoebic ..... while to select parents from accessions, Pov80 and Pov79 ... nology (DBT), Govt. of India, for financial assistance in the form.

Phosphorelay of non-orthodox two component systems functions through a bi-molecular mechanism in vivo

DEFF Research Database (Denmark)

Jovanovic, Goran; Sheng, Xia; Ale, Angelique

2015-01-01

the functional relevance of the dimerization of a non-orthodox or hybrid histidine kinase along which the phosphorelay takes place has been a subject of debate. We use a combination of molecular and genetic approaches, coupled to mathematical and statistical modelling, to demonstrate that the different possible...... intra- and inter-molecular mechanisms of phosphotransfer are formally non-identifiable in Escherichia coli expressing the ArcB non-orthodox histidine kinase used in anoxic redox control. In order to resolve this issue we further analyse the mathematical model in order to identify discriminatory...

Genetic Diversity Analysis in 27 Tomato Accessions Using Morphological and Molecular Markers

Directory of Open Access Journals (Sweden)

Catur Herison

2018-02-01

Full Text Available Genetic diversity is the most important aspect in tomato breeding activities. Better assessment on the diversity of the collected accessions will come up with better result of the cultivar development. This study aimed at analyzing the genetic diversity of 27 tomato accessions by morphological and molecular markers. Twenty seven accessions collected from various regions of Indonesia were planted in the field and evaluated for their morphological traits, and RAPD analyzed for their molecular markers. The UPGMA clustering analyzes, elaborating the combination of morphological and molecular data, indicated that the tomato accessions could be grouped into 5 major groups with 70 % genetic similarity levels. Current study indicated that although many accessions came from different locations, they congregated into the same group. Cherry, Kudamati 1 and Lombok 3 were the farthest genetic distant accessions to the others. Those three genotypes will be the most valuable accessions, when they were crossed with other accessions, for designing a prospective breeding program in the future.

Dissecting the Molecular Mechanisms of Neurodegenerative Diseases through Network Biology

Directory of Open Access Journals (Sweden)

Jose A. Santiago

2017-05-01

Full Text Available Neurodegenerative diseases are rarely caused by a mutation in a single gene but rather influenced by a combination of genetic, epigenetic and environmental factors. Emerging high-throughput technologies such as RNA sequencing have been instrumental in deciphering the molecular landscape of neurodegenerative diseases, however, the interpretation of such large amounts of data remains a challenge. Network biology has become a powerful platform to integrate multiple omics data to comprehensively explore the molecular networks in the context of health and disease. In this review article, we highlight recent advances in network biology approaches with an emphasis in brain-networks that have provided insights into the molecular mechanisms leading to the most prevalent neurodegenerative diseases including Alzheimer’s (AD, Parkinson’s (PD and Huntington’s diseases (HD. We discuss how integrative approaches using multi-omics data from different tissues have been valuable for identifying biomarkers and therapeutic targets. In addition, we discuss the challenges the field of network medicine faces toward the translation of network-based findings into clinically actionable tools for personalized medicine applications.

Molecular genetic gene-environment studies using candidate genes in schizophrenia: a systematic review.

Science.gov (United States)

Modinos, Gemma; Iyegbe, Conrad; Prata, Diana; Rivera, Margarita; Kempton, Matthew J; Valmaggia, Lucia R; Sham, Pak C; van Os, Jim; McGuire, Philip

2013-11-01

The relatively high heritability of schizophrenia suggests that genetic factors play an important role in the etiology of the disorder. On the other hand, a number of environmental factors significantly influence its incidence. As few direct genetic effects have been demonstrated, and there is considerable inter-individual heterogeneity in the response to the known environmental factors, interactions between genetic and environmental factors may be important in determining whether an individual develops the disorder. To date, a considerable number of studies of gene-environment interactions (G×E) in schizophrenia have employed a hypothesis-based molecular genetic approach using candidate genes, which have led to a range of different findings. This systematic review aims to summarize the results from molecular genetic candidate studies and to review challenges and opportunities of this approach in psychosis research. Finally, we discuss the potential of future prospects, such as new studies that combine hypothesis-based molecular genetic candidate approaches with agnostic genome-wide association studies in determining schizophrenia risk. © 2013 Elsevier B.V. All rights reserved.

Genetic diversity in cultivated carioca common beans based on molecular marker analysis

Directory of Open Access Journals (Sweden)

Juliana Morini Küpper Cardoso Perseguini

2011-01-01

Full Text Available A wide array of molecular markers has been used to investigate the genetic diversity among common bean species. However, the best combination of markers for studying such diversity among common bean cultivars has yet to be determined. Few reports have examined the genetic diversity of the carioca bean, commercially one of the most important common beans in Brazil. In this study, we examined the usefulness of two molecular marker systems (simple sequence repeats - SSRs and amplified fragment length polymorphisms - AFLPs for assessing the genetic diversity of carioca beans. The amount of information provided by Roger's modified genetic distance was used to analyze SSR data and Jaccards similarity coefficient was used for AFLP data. Seventy SSRs were polymorphic and 20 AFLP primer combinations produced 635 polymorphic bands. Molecular analysis showed that carioca genotypes were quite diverse. AFLPs revealed greater genetic differentiation and variation within the carioca genotypes (Gst = 98% and Fst = 0.83, respectively than SSRs and provided better resolution for clustering the carioca genotypes. SSRs and AFLPs were both suitable for assessing the genetic diversity of Brazilian carioca genotypes since the number of markers used in each system provided a low coefficient of variation. However, fingerprint profiles were generated faster with AFLPs, making them a better choice for assessing genetic diversity in the carioca germplasm.

Molecular Theory of the Living Cell Concepts, Molecular Mechanisms, and Biomedical Applications

CERN Document Server

Ji, Sungchul

2012-01-01

This book presents a comprehensive molecular theory of the living cell based on over thirty concepts, principles and laws imported from thermodynamics, statistical mechanics, quantum mechanics, chemical kinetics, informatics, computer science, linguistics, semiotics, and philosophy. The author formulates physically, chemically and enzymologically realistic molecular mechanisms to account for the basic living processes such as ligand-receptor interactions, protein folding, single-molecule enzymic catalysis, force-generating mechanisms in molecular motors, signal transduction, regulation of the genome-wide RNA metabolism, morphogenesis, the micro-macro coupling in coordination dynamics, the origin of life, and the mechanisms of biological evolution itself. Possible solutions to basic and practical problems facing contemporary biology and biomedical sciences have been suggested, including pharmacotheragnostics and personalized medicine.

[The development of molecular human genetics and its significance for perspectives of modern medicine].

Science.gov (United States)

Coutelle, C; Speer, A; Grade, K; Rosenthal, A; Hunger, H D

1989-01-01

The introduction of molecular human genetics has become a paradigma for the application of genetic engineering in medicine. The main principles of this technology are the isolation of molecular probes, their application in hybridization reactions, specific gene-amplification by the polymerase chain reaction, and DNA sequencing reactions. These methods are used for the analysis of monogenic diseases by linkage studies and the elucidation of the molecular defect causing these conditions, respectively. They are also the basis for genomic diagnosis of monogenic diseases, introduced into the health care system of the GDR by a national project on Duchenne/Becker muscular dystrophy, Cystic Fibrosis and Phenylketonuria. The rapid development of basic research on the molecular analysis of the human genome and genomic diagnosis indicates, that human molecular genetics is becoming a decisive basic discipline of modern medicine.

Bacillus subtilis as a Platform for Molecular Characterisation of Regulatory Mechanisms of Enterococcus faecalis Resistance against Cell Wall Antibiotics

OpenAIRE

Fang, Chong; Stiegeler, Emanuel; Cook, Gregory M.; Mascher, Thorsten; Gebhard, Susanne

2014-01-01

To combat antibiotic resistance of Enterococcus faecalis, a better understanding of the molecular mechanisms, particularly of antibiotic detection, signal transduction and gene regulation is needed. Because molecular studies in this bacterium can be challenging, we aimed at exploiting the genetically highly tractable Gram-positive model organism Bacillus subtilis as a heterologous host. Two fundamentally different regulators of E. faecalis resistance against cell wall antibiotics, the bacitra...

Molecular genetics and genomics generate new insights into invertebrate pest invasions.

Science.gov (United States)

Kirk, Heather; Dorn, Silvia; Mazzi, Dominique

2013-07-01

Invertebrate pest invasions and outbreaks are associated with high social, economic, and ecological costs, and their significance will intensify with an increasing pressure on agricultural productivity as a result of human population growth and climate change. New molecular genetic and genomic techniques are available and accessible, but have been grossly underutilized in studies of invertebrate pest invasions, despite that they are useful tools for applied pest management and for understanding fundamental features of pest invasions including pest population demographics and adaptation of pests to novel and/or changing environments. Here, we review current applications of molecular genetics and genomics in the study of invertebrate pest invasions and outbreaks, and we highlight shortcomings from the current body of research. We then discuss recent conceptual and methodological advances in the areas of molecular genetics/genomics and data analysis, and we highlight how these advances will further our understanding of the demographic, ecological, and evolutionary features of invertebrate pest invasions. We are now well equipped to use molecular data to understand invertebrate dispersal and adaptation, and this knowledge has valuable applications in agriculture at a time when these are critically required.

Systems Genetics Reveals the Functional Context of PCOS Loci and Identifies Genetic and Molecular Mechanisms of Disease Heterogeneity

Science.gov (United States)

Xu, Ning; Cui, Jinrui; Mengesha, Emebet; Chen, Yii-Der I.; Taylor, Kent D.; Azziz, Ricardo; Goodarzi, Mark O.

2015-01-01

Genome wide association studies (GWAS) have revealed 11 independent risk loci for polycystic ovary syndrome (PCOS), a common disorder in young women characterized by androgen excess and oligomenorrhea. To put these risk loci and the single nucleotide polymorphisms (SNPs) therein into functional context, we measured DNA methylation and gene expression in subcutaneous adipose tissue biopsies to identify PCOS-specific alterations. Two genes from the LHCGR region, STON1-GTF2A1L and LHCGR, were overexpressed in PCOS. In analysis stratified by obesity, LHCGR was overexpressed only in non-obese PCOS women. Although not differentially expressed in the entire PCOS group, INSR was underexpressed in obese PCOS subjects only. Alterations in gene expression in the LHCGR, RAB5B and INSR regions suggest that SNPs in these loci may be functional and could affect gene expression directly or indirectly via epigenetic alterations. We identified reduced methylation in the LHCGR locus and increased methylation in the INSR locus, changes that are concordant with the altered gene expression profiles. Complex patterns of meQTL and eQTL were identified in these loci, suggesting that local genetic variation plays an important role in gene regulation. We propose that non-obese PCOS women possess significant alterations in LH receptor expression, which drives excess androgen secretion from the ovary. Alternatively, obese women with PCOS possess alterations in insulin receptor expression, with underexpression in metabolic tissues and overexpression in the ovary, resulting in peripheral insulin resistance and excess ovarian androgen production. These studies provide a genetic and molecular basis for the reported clinical heterogeneity of PCOS. PMID:26305227

Systems Genetics Reveals the Functional Context of PCOS Loci and Identifies Genetic and Molecular Mechanisms of Disease Heterogeneity.

Science.gov (United States)

Jones, Michelle R; Brower, Meredith A; Xu, Ning; Cui, Jinrui; Mengesha, Emebet; Chen, Yii-Der I; Taylor, Kent D; Azziz, Ricardo; Goodarzi, Mark O

2015-08-01

Genome wide association studies (GWAS) have revealed 11 independent risk loci for polycystic ovary syndrome (PCOS), a common disorder in young women characterized by androgen excess and oligomenorrhea. To put these risk loci and the single nucleotide polymorphisms (SNPs) therein into functional context, we measured DNA methylation and gene expression in subcutaneous adipose tissue biopsies to identify PCOS-specific alterations. Two genes from the LHCGR region, STON1-GTF2A1L and LHCGR, were overexpressed in PCOS. In analysis stratified by obesity, LHCGR was overexpressed only in non-obese PCOS women. Although not differentially expressed in the entire PCOS group, INSR was underexpressed in obese PCOS subjects only. Alterations in gene expression in the LHCGR, RAB5B and INSR regions suggest that SNPs in these loci may be functional and could affect gene expression directly or indirectly via epigenetic alterations. We identified reduced methylation in the LHCGR locus and increased methylation in the INSR locus, changes that are concordant with the altered gene expression profiles. Complex patterns of meQTL and eQTL were identified in these loci, suggesting that local genetic variation plays an important role in gene regulation. We propose that non-obese PCOS women possess significant alterations in LH receptor expression, which drives excess androgen secretion from the ovary. Alternatively, obese women with PCOS possess alterations in insulin receptor expression, with underexpression in metabolic tissues and overexpression in the ovary, resulting in peripheral insulin resistance and excess ovarian androgen production. These studies provide a genetic and molecular basis for the reported clinical heterogeneity of PCOS.

Molecular genetic analysis of consanguineous families with primary ...

Indian Academy of Sciences (India)

MUZAMMIL AHMAD KHAN

3Institute of Human Genetics, Medical University of Graz, Graz 8010, Austria. 4Department of Cell and ... Materials and methods. Family recruitment and sample collection ..... 2014 A Drosophila genetic resource of mutats to study mechanism ...

Molecular mechanics calculations on cobalt phthalocyanine dimers

NARCIS (Netherlands)

Heuts, J.P.A.; Schipper, E.T.W.M.; Piet, P.; German, A.L.

1995-01-01

In order to obtain insight into the structure of cobalt phthalocyanine dimers, molecular mechanics calculations were performed on dimeric cobalt phthalocyanine species. Molecular mechanics calculations are first presented on monomeric cobalt(II) phthalocyanine. Using the Tripos force field for the

Plant genetic and molecular responses to water deficit

Directory of Open Access Journals (Sweden)

Silvio Salvi

2011-02-01

Full Text Available Plant productivity is severely affected by unfavourable environmental conditions (biotic and abiotic stresses. Among others, water deficit is the plant stress condition which mostly limits the quality and the quantity of plant products. Tolerance to water deficit is a polygenic trait strictly dependent on the coordinated expression of a large set of genes coding for proteins directly involved in stress-induced protection/repair mechanisms (dehydrins, chaperonins, enzymes for the synthesis of osmoprotectants and detoxifying compounds, and others as well as genes involved in transducing the stress signal and regulating gene expression (transcription factors, kinases, phosphatases. Recently, research activities in the field evolved from the study of single genes directly involved in cellular stress tolerance (functional genes to the identification and characterization of key regulatory genes involved in stress perception and transduction and able to rapidly and efficiently activate the complex gene network involved in the response to stress. The complexity of the events occurring in response to stress have been recently approached by genomics tools; in fact the analysis of transcriptome, proteome and metabolome of a plant tissue/cell in response to stress already allowed to have a global view of the cellular and molecular events occurring in response to water deficit, by the identification of genes activated and co-regulated by the stress conditions and the characterization of new signalling pathways. Moreover the recent application of forward and reverse genetic approaches, trough mutant collection development, screening and characterization, is giving a tremendous impulse to the identification of gene functions with key role in stress tolerance. The integration of data obtained by high-throughput genomic approaches, by means of powerful informatic tools, is allowing nowadays to rapidly identify of major genes/QTLs involved in stress tolerance

Molecular Insights into the Genetic Diversity of Garcinia cambogia Germplasm Accessions

Directory of Open Access Journals (Sweden)

C Tharachand

2015-10-01

Full Text Available ABSTRACTIn this work, the genetic relationship among twelveGarcinia cambogia (Gaertn. Desr. accessions were evaluated using Random Amplified Polymorphic DNA markers. The samples were part of the germplasm collected and maintained at NBPGR Regional station, Thrissur, India. Out of thirty RAPD primers used for screening, seven primers produced a total of 128 polymorphic markers in twelve accessions. The Polymorphic Information Content (PIC ranged from 0.28 (OPA18 to 0.37 (OPA9 and Marker Index (MI ranged between 3.61 (OPA12 and 5.93 (OPA3 among the primers used. Jaccard's coefficient of genetic similarity ranged between 0.07 and 0.64. The dendrogram constructed based on the similarity matrix generated from the molecular and morphological data showed the genetic relationship among the sampled accessions. Mantel matrix test showed a positive correlation (r = 0.49 between the cluster analysis of RAPD data and morphological data. The clustering pattern in the molecular dendrogram and Principle Coordinate Analysis (PCoA showed that the genotypes were diverse, which was in congruence with the similarity index values and morphological dendrogram. High frequency of similarity values in the range of 0.11 to 0.17 suggested the existence of high genetic diversity among the accessions. The high level of genetic diversity among the studied accessions ofG.cambogia was also supported by the large variation in the morphological characters observed in the flowers, leaves, fruits and seeds of these sampled accessions. This is the first report for the molecular based genetic diversity studies for these accessions.

Towards a Better Understanding of the Molecular Mechanisms Involved in Sunlight-Induced Melanoma

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Williams Mandy

2005-01-01

Full Text Available Although much less prevalent than its nonmelanoma skin cancer counterparts, cutaneous malignant melanoma (CMM is the most lethal human skin cancer. Epidemiological and biological studies have established a strong link between lifetime exposure to ultraviolet (UV light, particularly sunburn in childhood, and the development of melanoma. However, the specific molecular targets of this environmental carcinogen are not known. Data obtained from genetic and molecular studies over the last few years have identified the INK4a/ARF locus as the “gatekeeper” melanoma suppressor, encoding two tumour suppressor proteins in human, p16 INK4a and p14 ARF . Recent developments in molecular biotechnology and research using laboratory animals have made a significant gene breakthrough identifying the components of the p16 INK4a /Rb pathway as the principal and rate-limiting targets of UV radiation actions in melanoma formation. This review summarizes the current knowledge of the molecular mechanisms involved in melanoma development and its relationship to sunlight UV radiation.

Genetic diversity analysis of common beans based on molecular markers

Directory of Open Access Journals (Sweden)

Homar R. Gill-Langarica

2011-01-01

Full Text Available A core collection of the common bean (Phaseolus vulgaris L., representing genetic diversity in the entire Mexican holding, is kept at the INIFAP (Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias, Mexico Germplasm Bank. After evaluation, the genetic structure of this collection (200 accessions was compared with that of landraces from the states of Oaxaca, Chiapas and Veracruz (10 genotypes from each, as well as a further 10 cultivars, by means of four amplified fragment length polymorphisms (AFLP +3/+3 primer combinations and seven simple sequence repeats (SSR loci, in order to define genetic diversity, variability and mutual relationships. Data underwent cluster (UPGMA and molecular variance (AMOVA analyses. AFLP analysis produced 530 bands (88.5% polymorphic while SSR primers amplified 174 alleles, all polymorphic (8.2 alleles per locus. AFLP indicated that the highest genetic diversity was to be found in ten commercial-seed classes from two major groups of accessions from Central Mexico and Chiapas, which seems to be an important center of diversity in the south. A third group included genotypes from Nueva Granada, Mesoamerica, Jalisco and Durango races. Here, SSR analysis indicated a reduced number of shared haplotypes among accessions, whereas the highest genetic components of AMOVA variation were found within accessions. Genetic diversity observed in the common-bean core collection represents an important sample of the total Phaseolus genetic variability at the main Germplasm Bank of INIFAP. Molecular marker strategies could contribute to a better understanding of the genetic structure of the core collection as well as to its improvement and validation.

Genetic diversity analysis of common beans based on molecular markers

Directory of Open Access Journals (Sweden)

Homar R. Gill-Langarica

Full Text Available A core collection of the common bean (Phaseolus vulgaris L., representing genetic diversity in the entire Mexican holding, is kept at the INIFAP (Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias, Mexico Germplasm Bank. After evaluation, the genetic structure of this collection (200 accessions was compared with that of landraces from the states of Oaxaca, Chiapas and Veracruz (10 genotypes from each, as well as a further 10 cultivars, by means of four amplified fragment length polymorphisms (AFLP +3/+3 primer combinations and seven simple sequence repeats (SSR loci, in order to define genetic diversity, variability and mutual relationships. Data underwent cluster (UPGMA and molecular variance (AMOVA analyses. AFLP analysis produced 530 bands (88.5% polymorphic while SSR primers amplified 174 alleles, all polymorphic (8.2 alleles per locus. AFLP indicated that the highest genetic diversity was to be found in ten commercial-seed classes from two major groups of accessions from Central Mexico and Chiapas, which seems to be an important center of diversity in the south. A third group included genotypes from Nueva Granada, Mesoamerica, Jalisco and Durango races. Here, SSR analysis indicated a reduced number of shared haplotypes among accessions, whereas the highest genetic components of AMOVA variation were found within accessions. Genetic diversity observed in the common-bean core collection represents an important sample of the total Phaseolus genetic variability at the main Germplasm Bank of INIFAP. Molecular marker strategies could contribute to a better understanding of the genetic structure of the core collection as well as to its improvement and validation.

Genetic diversity analysis of common beans based on molecular markers.

Science.gov (United States)

Gill-Langarica, Homar R; Muruaga-Martínez, José S; Vargas-Vázquez, M L Patricia; Rosales-Serna, Rigoberto; Mayek-Pérez, Netzahualcoyotl

2011-10-01

A core collection of the common bean (Phaseolus vulgaris L.), representing genetic diversity in the entire Mexican holding, is kept at the INIFAP (Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias, Mexico) Germplasm Bank. After evaluation, the genetic structure of this collection (200 accessions) was compared with that of landraces from the states of Oaxaca, Chiapas and Veracruz (10 genotypes from each), as well as a further 10 cultivars, by means of four amplified fragment length polymorphisms (AFLP) +3/+3 primer combinations and seven simple sequence repeats (SSR) loci, in order to define genetic diversity, variability and mutual relationships. Data underwent cluster (UPGMA) and molecular variance (AMOVA) analyses. AFLP analysis produced 530 bands (88.5% polymorphic) while SSR primers amplified 174 alleles, all polymorphic (8.2 alleles per locus). AFLP indicated that the highest genetic diversity was to be found in ten commercial-seed classes from two major groups of accessions from Central Mexico and Chiapas, which seems to be an important center of diversity in the south. A third group included genotypes from Nueva Granada, Mesoamerica, Jalisco and Durango races. Here, SSR analysis indicated a reduced number of shared haplotypes among accessions, whereas the highest genetic components of AMOVA variation were found within accessions. Genetic diversity observed in the common-bean core collection represents an important sample of the total Phaseolus genetic variability at the main Germplasm Bank of INIFAP. Molecular marker strategies could contribute to a better understanding of the genetic structure of the core collection as well as to its improvement and validation.

A genetic analysis of segregation distortion revealed by molecular ...

Indian Academy of Sciences (India)

Journal of Genetics, Vol. 90, No. ... Segregation analysis was based on 64 molecular markers, including 26 .... FHB of RIL populations was controlled by quantitative trait ... The authors acknowledge financial support by the National Basic.

Management of insect pests: Nuclear and related molecular and genetic techniques

International Nuclear Information System (INIS)

1993-01-01

The conference was organized in eight sessions: opening, genetic engineering and molecular biology, genetics, operational programmes, F 1 sterility and insect behaviour, biocontrol, research and development on the tsetse fly, and quarantine. The 64 individual contributions have been indexed separately for INIS. Refs, figs and tabs

The Molecular Epidemiology and Genetic Environment of Carbapenemases Detected in Africa.

Science.gov (United States)

Sekyere, John Osei; Govinden, Usha; Essack, Sabiha

2016-01-01

Research articles describing carbapenemases and their genetic environments in Gram-negative bacteria were reviewed to determine the molecular epidemiology of carbapenemases in Africa. The emergence of resistance to the carbapenems, the last resort antibiotic for difficult to treat bacterial infections, affords clinicians few therapeutic options, with a resulting increase in morbidities, mortalities, and healthcare costs. However, the molecular epidemiology of carbapenemases throughout Africa is less described. Research articles and conference proceedings describing the genetic environment and molecular epidemiology of carbapenemases in Africa were retrieved from Google Scholar, Scifinder, Pubmed, Web of Science, and Science Direct databases. Predominant carbapenemase genes so far described in Africa include the blaOXA-48 type, blaIMP, blaVIM, and blaNDM in Acinetobacter baumannii, Klebsiella pneumoniae, Enterobacter cloacae, Citrobacter spp., and Escherichia coli carried on various plasmid types and sizes, transposons, and integrons. Class D and class B carbapenemases, mainly prevalent in A. baumannii, K. pneumoniae, E. cloacae, Citrobacter spp., and E. coli were the commonest carbapenemases. Carbapenemases are mainly reported in North and South Africa as under-resourced laboratories, lack of awareness and funding preclude the detection and reporting of carbapenemase-mediated resistance. Consequently, the true molecular epidemiology of carbapenemases and their genetic environment in Africa is still unknown.

Conformation analysis of trehalose. Molecular dynamics simulation and molecular mechanics

International Nuclear Information System (INIS)

Donnamaira, M.C.; Howard, E.I.; Grigera, J.R.

1992-09-01

Conformational analysis of the disaccharide trehalose is done by molecular dynamics and molecular mechanics. In spite of the different force fields used in each case, comparison between the molecular dynamics trajectories of the torsional angles of glycosidic linkage and energy conformational map shows a good agreement between both methods. By molecular dynamics it is observed a moderate mobility of the glycosidic linkage. The demands of computer time is comparable in both cases. (author). 6 refs, 4 figs

Systems Genetics Reveals the Functional Context of PCOS Loci and Identifies Genetic and Molecular Mechanisms of Disease Heterogeneity.

Directory of Open Access Journals (Sweden)

Michelle R Jones

2015-08-01

Full Text Available Genome wide association studies (GWAS have revealed 11 independent risk loci for polycystic ovary syndrome (PCOS, a common disorder in young women characterized by androgen excess and oligomenorrhea. To put these risk loci and the single nucleotide polymorphisms (SNPs therein into functional context, we measured DNA methylation and gene expression in subcutaneous adipose tissue biopsies to identify PCOS-specific alterations. Two genes from the LHCGR region, STON1-GTF2A1L and LHCGR, were overexpressed in PCOS. In analysis stratified by obesity, LHCGR was overexpressed only in non-obese PCOS women. Although not differentially expressed in the entire PCOS group, INSR was underexpressed in obese PCOS subjects only. Alterations in gene expression in the LHCGR, RAB5B and INSR regions suggest that SNPs in these loci may be functional and could affect gene expression directly or indirectly via epigenetic alterations. We identified reduced methylation in the LHCGR locus and increased methylation in the INSR locus, changes that are concordant with the altered gene expression profiles. Complex patterns of meQTL and eQTL were identified in these loci, suggesting that local genetic variation plays an important role in gene regulation. We propose that non-obese PCOS women possess significant alterations in LH receptor expression, which drives excess androgen secretion from the ovary. Alternatively, obese women with PCOS possess alterations in insulin receptor expression, with underexpression in metabolic tissues and overexpression in the ovary, resulting in peripheral insulin resistance and excess ovarian androgen production. These studies provide a genetic and molecular basis for the reported clinical heterogeneity of PCOS.

Molecular genetic markers for thyroid FNAB. Established assays and future perspective.

Science.gov (United States)

Musholt, Thomas J; Musholt, P B

2015-01-01

Thyroid nodules > 1 cm are observed in about 12% of unselected adult employees aged 18-65 years screened by ultrasound scan (40). While intensive ultrasound screening leads to early detection of thyroid diseases, the determination of benign or malignant behaviour remains uncertain and may trigger anxieties in many patients and their physicians. A considerable number of thyroid resections are consecutively performed due to suspicion of malignancy in the detected nodes. Fine needle aspiration biopsy (FNAB) has been recommended for the assessment of thyroid nodules to facilitate detection of thyroid carcinomas but also to rule out malignancy and thereby avoid unnecessary thyroid resections. However, cytology results are dependent on experience of the respective cytologist and unfortunately inconclusive in many cases. Molecular genetic markers are already used nowadays to enhance sensitivity and specificity of FNAB cytology in some centers in Germany. The most clinically relevant molecular genetic markers as pre-operative diagnostic tools and the clinical implications for the intraoperative and postoperative management were reviewed. Molecular genetic markers predominantly focus on the preoperative detection of thyroid malignancies rather than the exclusion of thyroid carcinomas. While some centers routinely assess FNABs, other centers concentrate on FNABs with cytology results of follicular neoplasia or suspicion of thyroid carcinoma. Predominantly mutations of BRAF, RET/PTC, RAS, and PAX8/PPARγ or expression of miRNAs are analyzed. However, only the detection of BRAF mutations predicts the presence of (papillary) thyroid malignancy with almost 98% probability, indicating necessity of oncologic thyroid resections irrespective of the cytology result. Other genetic alterations are associated with thyroid malignancy with varying frequency and achieve less impact on the clinical management. Molecular genetic analysis of FNABs is increasingly performed in Germany

76 FR 18227 - Molecular and Clinical Genetics Panel of the Medical Devices Advisory Committee; Notice of...

Science.gov (United States)

2011-04-01

...] Molecular and Clinical Genetics Panel of the Medical Devices Advisory Committee; Notice of Meeting... comment period for the notice announcing a meeting of the Molecular and Clinical Genetics Panel (the panel... Clinical Genetics Panel of the Medical Devices Advisory Committee, and the opening of a public docket to...

Molecular approaches for genetic improvement of seed quality and characterization of genetic diversity in soybean: a critical review.

Science.gov (United States)

Tripathi, Niraj; Khare, Dhirendra

2016-10-01

Soybean is an economically important leguminous crop. Genetic improvements of soybeans have focused on enhancement of seed and oil yield, development of varieties suited to different cropping systems, and breeding resistant/tolerant varieties for various biotic and abiotic stresses. Plant breeders have used conventional breeding techniques for the improvement of these traits in soybean. The conventional breeding process can be greatly accelerated through the application of molecular and genomic approaches. Molecular markers have proved to be a new tool in soybean breeding by enhancing selection efficiency in a rapid and time-bound manner. An overview of molecular approaches for the genetic improvement of soybean seed quality parameters, considering recent applications of marker-assisted selection and 'omics' research, is provided in this article.

Molecular genetic approach for screening of hereditary non-polyposis colorectal cancer

Directory of Open Access Journals (Sweden)

Metka Ravnik-Glavač

2005-07-01

Full Text Available Background: The main goal of knowledge concerning human diseases is to transfer as much as possible useful information into clinical applications. Hereditary non-polyposis colorectal cancer (HNPCC is the most common autosomal dominant inherited predisposition for colorectal cancer, accounting for 1–2% of all bowel cancer. The only way to diagnose HNPCC is by a family history consistent with the disease defined by International Collaborative Group on HNPCC (Amsterdam criteria I and II. The main molecular cause of HNPCC is a constitutional mutation in one of the mismatch repair (MMR genes. Since HNPCC mutations have been detected also in families that did not fulfil the Amsterdam criteria, molecular genetic characteristics of HNPCC cancers have been proposed as valuable first step in HNPCC identification. Microsatellite instability is present in about 90% of cancers of HNPCC patients. However, of all MSI colorectal cancers 80– 90% are sporadic. Several molecular mechanisms have been uncovered that enable distinguishing to some extent between sporadic and HNPCC cancers with MSI including hypermethylation of hMLH1 promoter and frequent mutations in BAX and TGFBR2 in sporadic CRC with MSI-H.Conclusions: The determination of MSI status and careful separation of MSI positive colorectal cancer into sporadic MSIL, sporadic MSI-H, and HNPCC MSI-H followed by mutation detection in MMR genes is important for prevention, screening and management of colorectal cancer. In some studies we and others have already shown that large-scale molecular genetic analysis for HNPCC can be done and is sensitive enough to approve population screening. Population screening includes also colonoscopy which is restricted only to the obligate carriers of the mutation. This enables that the disease is detected in earlier stages which would greatly decrease medical treatment costs and most importantly decrease mortality. In Slovenia we have started population screening based

Molecular research on the genetic diversity of Tunisian date palm ...

African Journals Online (AJOL)

Molecular research on the genetic diversity of Tunisian date palm ( Phoenix dactylifera L.) using the random amplified microsatellite polymorphism (RAMPO) and amplified fragment length polymorphism (AFLP) methods.

Molecular genetic diversity in populations of the stingless bee Plebeia remota: A case study

Directory of Open Access Journals (Sweden)

Flávio de Oliveira Francisco

2013-01-01

Full Text Available Genetic diversity is a major component of the biological diversity of an ecosystem. The survival of a population may be seriously threatened if its genetic diversity values are low. In this work, we measured the genetic diversity of the stingless bee Plebeia remota based on molecular data obtained by analyzing 15 microsatellite loci and sequencing two mitochondrial genes. Population structure and genetic diversity differed depending on the molecular marker analyzed: microsatellites showed low population structure and moderate to high genetic diversity, while mitochondrial DNA (mtDNA showed high population structure and low diversity in three populations. Queen philopatry and male dispersal behavior are discussed as the main reasons for these findings.

Enhancing genetic gain in the era of molecular breeding.

Science.gov (United States)

Xu, Yunbi; Li, Ping; Zou, Cheng; Lu, Yanli; Xie, Chuanxiao; Zhang, Xuecai; Prasanna, Boddupalli M; Olsen, Michael S

2017-05-17

As one of the important concepts in conventional quantitative genetics and breeding, genetic gain can be defined as the amount of increase in performance that is achieved annually through artificial selection. To develop pro ducts that meet the increasing demand of mankind, especially for food and feed, in addition to various industrial uses, breeders are challenged to enhance the potential of genetic gain continuously, at ever higher rates, while they close the gaps that remain between the yield potential in breeders' demonstration trials and the actual yield in farmers' fields. Factors affecting genetic gain include genetic variation available in breeding materials, heritability for traits of interest, selection intensity, and the time required to complete a breeding cycle. Genetic gain can be improved through enhancing the potential and closing the gaps, which has been evolving and complemented with modern breeding techniques and platforms, mainly driven by molecular and genomic tools, combined with improved agronomic practice. Several key strategies are reviewed in this article. Favorable genetic variation can be unlocked and created through molecular and genomic approaches including mutation, gene mapping and discovery, and transgene and genome editing. Estimation of heritability can be improved by refining field experiments through well-controlled and precisely assayed environmental factors or envirotyping, particularly for understanding and controlling spatial heterogeneity at the field level. Selection intensity can be significantly heightened through improvements in the scale and precision of genotyping and phenotyping. The breeding cycle time can be shortened by accelerating breeding procedures through integrated breeding approaches such as marker-assisted selection and doubled haploid development. All the strategies can be integrated with other widely used conventional approaches in breeding programs to enhance genetic gain. More transdisciplinary

Exploring the genetics and non-cell autonomous mechanisms underlying ALS/FTLD.

Science.gov (United States)

Chen, Hongbo; Kankel, Mark W; Su, Susan C; Han, Steve W S; Ofengeim, Dimitry

2018-03-01

Although amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, was first described in 1874, a flurry of genetic discoveries in the last 10 years has markedly increased our understanding of this disease. These findings have not only enhanced our knowledge of mechanisms leading to ALS, but also have revealed that ALS shares many genetic causes with another neurodegenerative disease, frontotemporal lobar dementia (FTLD). In this review, we survey how recent genetic studies have bridged our mechanistic understanding of these two related diseases and how the genetics behind ALS and FTLD point to complex disorders, implicating non-neuronal cell types in disease pathophysiology. The involvement of non-neuronal cell types is consistent with a non-cell autonomous component in these diseases. This is further supported by studies that identified a critical role of immune-associated genes within ALS/FTLD and other neurodegenerative disorders. The molecular functions of these genes support an emerging concept that various non-autonomous functions are involved in neurodegeneration. Further insights into such a mechanism(s) will ultimately lead to a better understanding of potential routes of therapeutic intervention. Facts ALS and FTLD are severe neurodegenerative disorders on the same disease spectrum. Multiple cellular processes including dysregulation of RNA homeostasis, imbalance of proteostasis, contribute to ALS/FTLD pathogenesis. Aberrant function in non-neuronal cell types, including microglia, contributes to ALS/FTLD. Strong neuroimmune and neuroinflammatory components are associated with ALS/FTLD patients. Open Questions Why can patients with similar mutations have different disease manifestations, i.e., why do C9ORF72 mutations lead to motor neuron loss in some patients while others exhibit loss of neurons in the frontotemporal lobe? Do ALS causal mutations result in microglial dysfunction and contribute to ALS/FTLD pathology? How do microglia

Distinct Mechanisms of Nuclease-Directed DNA-Structure-Induced Genetic Instability in Cancer Genomes.

Science.gov (United States)

Zhao, Junhua; Wang, Guliang; Del Mundo, Imee M; McKinney, Jennifer A; Lu, Xiuli; Bacolla, Albino; Boulware, Stephen B; Zhang, Changsheng; Zhang, Haihua; Ren, Pengyu; Freudenreich, Catherine H; Vasquez, Karen M

2018-01-30

Sequences with the capacity to adopt alternative DNA structures have been implicated in cancer etiology; however, the mechanisms are unclear. For example, H-DNA-forming sequences within oncogenes have been shown to stimulate genetic instability in mammals. Here, we report that H-DNA-forming sequences are enriched at translocation breakpoints in human cancer genomes, further implicating them in cancer etiology. H-DNA-induced mutations were suppressed in human cells deficient in the nucleotide excision repair nucleases, ERCC1-XPF and XPG, but were stimulated in cells deficient in FEN1, a replication-related endonuclease. Further, we found that these nucleases cleaved H-DNA conformations, and the interactions of modeled H-DNA with ERCC1-XPF, XPG, and FEN1 proteins were explored at the sub-molecular level. The results suggest mechanisms of genetic instability triggered by H-DNA through distinct structure-specific, cleavage-based replication-independent and replication-dependent pathways, providing critical evidence for a role of the DNA structure itself in the etiology of cancer and other human diseases. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Molecular genetics of hemophilia A: Clinical perspectives | Tantawy ...

African Journals Online (AJOL)

Since the publication of the sequence of the factor VIII (F8) gene in 1984, a large number of mutations that cause hemophilia A have been identified and a significant progress has been made in translating this knowledge for clinical diagnostic and therapeutic purposes. Molecular genetic testing is used to determine the ...

Nasopharyngeal angiofibroma: review of the genetic and molecular aspects

Directory of Open Access Journals (Sweden)

Oliveira, Viviane Boaventura de

2008-09-01

Full Text Available Introduction: Juvenile nasopharyngeal angiofibroma (JNA is a rare fibrovascular tumor of unknown etiology, with few studies analyzing its pathogenesis. Objective: Reviewing JNA's pathogenesis, emphasizing genetic and molecular aspects. Method: All the relevant articles indexed in PUBMED and LILACS, besides reference book chapters, published between 1959 and 2007 were reviewed. Results: The sex selectivity seen in JNA may be explained by intranuclear accumulation of androgen receptor and beta-catenin, a co-activator which increases the tumor sensitivity to androgynous. The genetic alterations seen in JNA are most frequently located in sexual chromosomes. A number of growth factors seem to be related to the tumor pathogenesis. The insulin-like growth factor II is highly expressed while the vascular endothelial growth factor and the transforming growth factor beta are released by stromal cells and may influence the JNA's growth and vascularization. Conclusion: In spite of the scarce data describing the JNA etiology and pathogenesis, genetic and molecular factors seem to collaborate to the understanding of the disease's many clinical and morphological features. Knowledge regarding these specific issues could contribute for the establishment of potential therapeutic targets in the future.

Molecular Mechanisms of Preeclampsia

Directory of Open Access Journals (Sweden)

N. Vitoratos

2012-01-01

Full Text Available Preeclampsia is one of the leading causes of maternal morbidity/mortality. The pathogenesis of preeclampsia is still under investigation. The aim of this paper is to present the molecular mechanisms implicating in the pathway leading to preeclampsia.

Shared genetic origins of allergy and autoimmune diseases

DEFF Research Database (Denmark)

Waage, J. E.; Kreiner-Møller, E.; Standl, M.

2015-01-01

Parallel increases in allergy and autoimmune disease prevalence in recent time suggest shared, but yet unknown, etiologies. Here, we investigated shared genetic loci and molecular pathways to identify possible shared disease mechanisms between allergy and autoimmune diseases.......Parallel increases in allergy and autoimmune disease prevalence in recent time suggest shared, but yet unknown, etiologies. Here, we investigated shared genetic loci and molecular pathways to identify possible shared disease mechanisms between allergy and autoimmune diseases....

Molecular Markers for Genetic Diversity Studies of European Hare (Lepus europaeus Pallas, 1778 Populations

Directory of Open Access Journals (Sweden)

Noémi Soós

2015-05-01

Full Text Available The purpose of this article is to give an overview of different molecular techniques which have been used in studies concerning population genetic issues of Lepus species and specifically of L. europaeus. The importance of these researches is ever-growing as the European populations of the brown hare have suffered several falloffs as a consequent upon both natural and anthropogenic effects. With developing tools and techniques molecular genetics have become the centrepiece of population genetics and conservation biology. Nucleic acid methods based on both bi- and uniparentally inherited DNA (allozymes, microsatellites, Y chromosome, mtDNA are often used to study genetic structure, diversity and phylogeography of different species’ populations due to their effectiveness in identifying genetic variability

Construction of intergeneric conjugal transfer for molecular genetic ...

African Journals Online (AJOL)

SAM

2014-03-26

Mar 26, 2014 ... The attB integration site in the S. mobaraensis genome was detected as a single attB ... present study, to promote the molecular genetic study of. S. mobaraensis .... further increase in the number of E. coli donor cells. (≥1.25 × 108) (Choi et .... rational mutagenesis and random mutagenesis. Appl. Microbiol.

A molecular dynamics investigation into the mechanisms of alectinib resistance of three ALK mutants.

Science.gov (United States)

He, Muyang; Li, Weikang; Zheng, Qingchuan; Zhang, Hongxing

2018-01-11

Alectinib, a highly selective next-genetation anaplastic lymphoma kinase (ALK) inhibitor, has demonstrated promising antitumor activity in patients with ALK-positive non-small cell lung carcinomas (NSCLC). However, the therapeutic benefits of alectinib is inescapably hampered by the development of acquired resistant mutations in ALK. Despite the availability of ample experimental mutagenesis data, the molecular origin and the structural motifs under alectinib binding affinity deficiencies are still ambiguous. Here, molecular dynamics (MD) simulations and molecular mechanics generalized born surface area (MM-GBSA) calculation approaches were employed to elucidate the mechanisms of alectinib resistance induced by the mutations I1171N, V1180L, and L1198F. The MD results reveal that the studied mutations could trigger the dislocation of alectinib as well as conformational changes at the inhibitor binding site, thus induce the interactional changes between alectinib and mutants. The most influenced regions are the ligand binding entrance and the hinge region, which are considered to be the dominant binding motifs accounting for the binding affinity loss in mutants. The "key and lock mechanism" between the ethyl group at position 9 of alectinib and a recognition cavity in the hinge region of ALK is presented to illustrate the major molecular origin of drug resistance. Our results provide mechanistic insight into the effect of ALK mutations resistant to alectinib, which could contribute to further rational design of inhibitors to combat the acquired resistance. © 2018 Wiley Periodicals, Inc.

A quantum mechanics/molecular mechanics study on the hydrolysis mechanism of New Delhi metallo-β-lactamase-1.

Science.gov (United States)

Zhu, Kongkai; Lu, Junyan; Liang, Zhongjie; Kong, Xiangqian; Ye, Fei; Jin, Lu; Geng, Heji; Chen, Yong; Zheng, Mingyue; Jiang, Hualiang; Li, Jun-Qian; Luo, Cheng

2013-03-01

New Delhi metallo-β-lactamase-1 (NDM-1) has emerged as a major global threat to human health for its rapid rate of dissemination and ability to make pathogenic microbes resistant to almost all known β-lactam antibiotics. In addition, effective NDM-1 inhibitors have not been identified to date. In spite of the plethora of structural and kinetic data available, the accurate molecular characteristics of and details on the enzymatic reaction of NDM-1 hydrolyzing β-lactam antibiotics remain incompletely understood. In this study, a combined computational approach including molecular docking, molecular dynamics simulations and quantum mechanics/molecular mechanics calculations was performed to characterize the catalytic mechanism of meropenem catalyzed by NDM-1. The quantum mechanics/molecular mechanics results indicate that the ionized D124 is beneficial to the cleavage of the C-N bond within the β-lactam ring. Meanwhile, it is energetically favorable to form an intermediate if no water molecule coordinates to Zn2. Moreover, according to the molecular dynamics results, the conserved residue K211 plays a pivotal role in substrate binding and catalysis, which is quite consistent with previous mutagenesis data. Our study provides detailed insights into the catalytic mechanism of NDM-1 hydrolyzing meropenem β-lactam antibiotics and offers clues for the discovery of new antibiotics against NDM-1 positive strains in clinical studies.

Hamartomatous polyps - a clinical and molecular genetic study

DEFF Research Database (Denmark)

Jelsig, Anne Marie

2016-01-01

the knowledge on clinical course and molecular genetics in patients with HPs and HPS, and to investigate research participants' attitude towards the results of extensive genetic testing. Paper I: In the first paper we investigated the occurrence, anatomic distribution, and other demographics of juvenile polyps...... appearance. Patients with one or a few juvenile polyps are usually not offered clinical follow-up as the polyp(s) are considered not to harbour any malignant potential. Nevertheless, it is important to note that juvenile polyps and HPs are also found in patients with hereditary hamartomatous polyposis......-Jeghers syndrome, and the PTEN hamartoma tumour syndrome. Currently, the HPS diagnoses are based on clinical criteria and are often assisted with genetic testing as candidate genes have been described for each syndrome. This thesis is based on six scientific papers. The overall aim of the studies was to expand...

Implementation of molecular karyotyping in clinical genetics

Directory of Open Access Journals (Sweden)

Luca Lovrecic

2013-11-01

Full Text Available Rapid development of technologies for the study of the human genome is an expected step after the discovery and sequencing of the entire human genome. Chromosomal microarrays, which allow us to perform tens of thousands of previously individual experiments simultaneously, are being utilized in all areas of human genetics and genomics. Initially, this was applicable only for research purposes, but in the last few years their clinical diagnostic purposes are becoming more and more relevant. Using molecular karyotyping (also chromosomal microarray, comparative genomic hybridization with microarray, aCGH, one can analyze microdeletions / microduplications in the whole human genome at once. It is a first-tier cytogenetic diagnostic test instead of G-banded karyotyping in patients with developmental delay and/or congenital anomalies. Molecular karyotyping is used as a diagnostic test in patients with unexplained developmental delay and/or idiopathic intellectual disability and/or dysmorphic features and/or multiple congenital anomalies (DD/ID/DF/MCA. In addition, the method is used in prenatal diagnostics and in some centres also in preimplantation genetic diagnosis.The aim of this paper is to inform the professional community in the field about this new diagnostic method and its implementation in Slovenia, and to define the clinical situations where the method is appropriate.

Molecular machines with bio-inspired mechanisms.

Science.gov (United States)

Zhang, Liang; Marcos, Vanesa; Leigh, David A

2018-02-26

The widespread use of molecular-level motion in key natural processes suggests that great rewards could come from bridging the gap between the present generation of synthetic molecular machines-which by and large function as switches-and the machines of the macroscopic world, which utilize the synchronized behavior of integrated components to perform more sophisticated tasks than is possible with any individual switch. Should we try to make molecular machines of greater complexity by trying to mimic machines from the macroscopic world or instead apply unfamiliar (and no doubt have to discover or invent currently unknown) mechanisms utilized by biological machines? Here we try to answer that question by exploring some of the advances made to date using bio-inspired machine mechanisms.

Strengthening molecular genetics and training in craniosynostosis: The need of the hour

Science.gov (United States)

Barik, Mayadhar; Bajpai, Minu; Panda, Shasanka Shekhar; Malhotra, Arun; Samantaray, Jyotish Chandra; Dwivedi, Sada Nanda

2014-01-01

Craniosynostosis (CS) is premature fusion of skull. It is divided into two groups: Syndromic craniosynostosis (SCS) and non-syndromic craniosynostosis (NSC). Its incidence in Indian population is 1:1000 live births where as in the USA it is 1:2500 live births. Its incidence varies from country to country. Molecular genetics having great interest and relevance in medical students, faculty, scientist, pediatric neurosurgeon and staff nurses, our objective was to educate the medical students, residents, researchers, clinicians, pediatric neurosurgeon, anesthetists, pediatricians, staff nurses and paramedics. We summarized here including with diagnosis, investigations, surgical therapy, induction therapy, and molecular therapy. Molecular genetics training is needed to know the information regarding development of skull, cranial connective tissue, craniofacial dysplasia, frame work, network of receptors and its etiopathogenesis. The important part is clinically with molecular therapy (MT) how to manage CS in rural sector and metropolitan cities need a special attention. PMID:25288859

Strengthening molecular genetics and training in craniosynostosis: The need of the hour

Directory of Open Access Journals (Sweden)

Mayadhar Barik

2014-01-01

Full Text Available Craniosynostosis (CS is premature fusion of skull. It is divided into two groups: Syndromic craniosynostosis (SCS and non-syndromic craniosynostosis (NSC. Its incidence in Indian population is 1:1000 live births where as in the USA it is 1:2500 live births. Its incidence varies from country to country. Molecular genetics having great interest and relevance in medical students, faculty, scientist, pediatric neurosurgeon and staff nurses, our objective was to educate the medical students, residents, researchers, clinicians, pediatric neurosurgeon, anesthetists, pediatricians, staff nurses and paramedics. We summarized here including with diagnosis, investigations, surgical therapy, induction therapy, and molecular therapy. Molecular genetics training is needed to know the information regarding development of skull, cranial connective tissue, craniofacial dysplasia, frame work, network of receptors and its etiopathogenesis. The important part is clinically with molecular therapy (MT how to manage CS in rural sector and metropolitan cities need a special attention.

Molecular genetics and livestock selection. Approaches, opportunities and risks

International Nuclear Information System (INIS)

Williams, J.L.

2005-01-01

Following domestication, livestock were selected both naturally through adaptation to their environments and by man so that they would fulfil a particular use. As selection methods have become more sophisticated, rapid progress has been made in improving those traits that are easily measured. However, selection has also resulted in decreased diversity. In some cases, improved breeds have replaced local breeds, risking the loss of important survival traits. The advent of molecular genetics provides the opportunity to identify the genes that control particular traits by a gene mapping approach. However, as with selection, the early mapping studies focused on traits that are easy to measure. Where molecular genetics can play a valuable role in livestock production is by providing the means to select effectively for traits that are difficult to measure. Identifying the genes underpinning particular traits requires a population in which these traits are segregating. Fortunately, several experimental populations have been created that have allowed a wide range of traits to be studied. Gene mapping work in these populations has shown that the role of particular genes in controlling variation in a given trait can depend on the genetic background. A second finding is that the most favourable alleles for a trait may in fact. be present in animals that perform poorly for the trait. In the long term, knowledge of -the genes controlling particular traits, and the way they interact with the genetic background, will allow introgression between breeds and the assembly of genotypes that are best suited to particular environments, producing animals with the desired characteristics. If used wisely, this approach will maintain genetic diversity while improving performance over a wide range of desired traits. (author)

Molecular mechanisms in compatibility and mechanical properties of Polyacrylamide/Polyvinyl alcohol blends.

Science.gov (United States)

Wei, Qinghua; Wang, Yanen; Che, Yu; Yang, Mingming; Li, Xinpei; Zhang, Yingfeng

2017-01-01

The objectives of this study were to develop a computational model based on molecular dynamics technique to investigate the compatibility and mechanical properties of Polyacrylamide (PAM)/Polyvinyl alcohol (PVA) blends. Five simulation models of PAM/PVA with different composition ratios (4/0, 3/1, 2/2, 1/3, 0/4) were constructed and simulated by using molecular dynamics (MD) simulation. The interaction mechanisms of molecular chains in PAM/PVA blend system were elaborated from the aspects of the compatibility, mechanical properties, binding energy and pair correlation function, respectively. The computed values of solubility parameters for PAM and PVA indicate PAM has a good miscibility with PVA. The results of the static mechanical analysis, based on the equilibrium structures of blends with differing component ratios, shows us that the elastic coefficient, engineering modulus, and ductility are increased with the addition of PVA content, which is 4/0 PAM/PVAPVAPVAPVAPVA. Moreover, binding energy results indicate that a stronger interaction exists among PVA molecular chains comparing with PAM molecular chains, which is why the mechanical properties of blend system increasing with the addition of PVA content. Finally, the results of pair correlation functions (PCFs) between polar functional groups and its surrounding hydrogen atoms, indicated they interact with each other mainly by hydrogen bonds, and the strength of three types of polar functional groups has the order of O(-OH)>O(-C=O)>N(-NH 2 ). This further elaborates the root reason why the mechanical properties of blend system increase with the addition of PVA content. Copyright © 2016 Elsevier Ltd. All rights reserved.

Genetics of immune-mediated disorders : from genome-wide association to molecular mechanism

NARCIS (Netherlands)

Kumar, Vinod; Wijmenga, Cisca; Xavier, Ramnik J.

2014-01-01

Genetic association studies have identified not only hundreds of susceptibility loci to immune-mediated diseases but also pinpointed causal amino-acid variants of HLA genes that contribute to many autoimmune reactions. Majority of non-HLA genetic variants are located within non-coding regulatory

Best practice guidelines for the molecular genetic diagnosis of Type 1 (HFE-related hereditary haemochromatosis

Directory of Open Access Journals (Sweden)

Barton David E

2006-11-01

Full Text Available Abstract Background Hereditary haemochromatosis (HH is a recessively-inherited disorder of iron over-absorption prevalent in Caucasian populations. Affected individuals for Type 1 HH are usually either homozygous for a cysteine to tyrosine amino acid substitution at position 282 (C282Y of the HFE gene, or compound heterozygotes for C282Y and for a histidine to aspartic acid change at position 63 (H63D. Molecular genetic testing for these two mutations has become widespread in recent years. With diverse testing methods and reporting practices in use, there was a clear need for agreed guidelines for haemochromatosis genetic testing. The UK Clinical Molecular Genetics Society has elaborated a consensus process for the development of disease-specific best practice guidelines for genetic testing. Methods A survey of current practice in the molecular diagnosis of haemochromatosis was conducted. Based on the results of this survey, draft guidelines were prepared using the template developed by UK Clinical Molecular Genetics Society. A workshop was held to develop the draft into a consensus document. The consensus document was then posted on the Clinical Molecular Genetics Society website for broader consultation and amendment. Results Consensus or near-consensus was achieved on all points in the draft guidelines. The consensus and consultation processes worked well, and outstanding issues were documented in an appendix to the guidelines. Conclusion An agreed set of best practice guidelines were developed for diagnostic, predictive and carrier testing for hereditary haemochromatosis and for reporting the results of such testing.

Molecular Genetic and Gene Therapy Studies of the Musculoskeletal System

National Research Council Canada - National Science Library

Baylink, David

2004-01-01

The primary goal of the proposed work is to apply several state of the art molecular genetic and gene therapy technologies to address fundamental questions in bone biology with a particular emphasis on attempting: l...

Genetics of human hydrocephalus

Science.gov (United States)

Williams, Michael A.; Rigamonti, Daniele

2006-01-01

Human hydrocephalus is a common medical condition that is characterized by abnormalities in the flow or resorption of cerebrospinal fluid (CSF), resulting in ventricular dilatation. Human hydrocephalus can be classified into two clinical forms, congenital and acquired. Hydrocephalus is one of the complex and multifactorial neurological disorders. A growing body of evidence indicates that genetic factors play a major role in the pathogenesis of hydrocephalus. An understanding of the genetic components and mechanism of this complex disorder may offer us significant insights into the molecular etiology of impaired brain development and an accumulation of the cerebrospinal fluid in cerebral compartments during the pathogenesis of hydrocephalus. Genetic studies in animal models have started to open the way for understanding the underlying pathology of hydrocephalus. At least 43 mutants/loci linked to hereditary hydrocephalus have been identified in animal models and humans. Up to date, 9 genes associated with hydrocephalus have been identified in animal models. In contrast, only one such gene has been identified in humans. Most of known hydrocephalus gene products are the important cytokines, growth factors or related molecules in the cellular signal pathways during early brain development. The current molecular genetic evidence from animal models indicate that in the early development stage, impaired and abnormal brain development caused by abnormal cellular signaling and functioning, all these cellular and developmental events would eventually lead to the congenital hydrocephalus. Owing to our very primitive knowledge of the genetics and molecular pathogenesis of human hydrocephalus, it is difficult to evaluate whether data gained from animal models can be extrapolated to humans. Initiation of a large population genetics study in humans will certainly provide invaluable information about the molecular and cellular etiology and the developmental mechanisms of human

Genetic theory – a suggested cupping therapy mechanism of action

OpenAIRE

Shaban , Tamer; Ravalia , Munir

2017-01-01

The Cupping Therapy mechanism of action is not clear. Cupping may increase local blood circulation, and may have an immunomodulation effect. Local and systemic effects of Cupping Therapy were reported. Genetic expression is a physiological process that regulates body functions. Genetic modulation is a reported acupuncture effect. In this article, the authors suggest genetic modulation theory as one of the possible mechanisms of action of cupping therapy.

Obstructive renal injury: from fluid mechanics to molecular cell biology.

Science.gov (United States)

Ucero, Alvaro C; Gonçalves, Sara; Benito-Martin, Alberto; Santamaría, Beatriz; Ramos, Adrian M; Berzal, Sergio; Ruiz-Ortega, Marta; Egido, Jesus; Ortiz, Alberto

2010-04-22

Urinary tract obstruction is a frequent cause of renal impairment. The physiopathology of obstructive nephropathy has long been viewed as a mere mechanical problem. However, recent advances in cell and systems biology have disclosed a complex physiopathology involving a high number of molecular mediators of injury that lead to cellular processes of apoptotic cell death, cell injury leading to inflammation and resultant fibrosis. Functional studies in animal models of ureteral obstruction using a variety of techniques that include genetically modified animals have disclosed an important role for the renin-angiotensin system, transforming growth factor-β1 (TGF-β1) and other mediators of inflammation in this process. In addition, high throughput techniques such as proteomics and transcriptomics have identified potential biomarkers that may guide clinical decision-making.

EMQN/CMGS best practice guidelines for the molecular genetic testing of Huntington disease

OpenAIRE

Losekoot, Monique; van Belzen, Martine J; Seneca, Sara; Bauer, Peter; Stenhouse, Susan A R; Barton, David E

2012-01-01

Huntington disease (HD) is caused by the expansion of an unstable polymorphic trinucleotide (CAG)n repeat in exon 1 of the HTT gene, which translates into an extended polyglutamine tract in the protein. Laboratory diagnosis of HD involves estimation of the number of CAG repeats. Molecular genetic testing for HD is offered in a wide range of laboratories both within and outside the European community. In order to measure the quality and raise the standard of molecular genetic testing in these ...

Transferability of MCR-1/2 Polymyxin Resistance: Complex Dissemination and Genetic Mechanism.

Science.gov (United States)

Feng, Youjun

2018-03-09

Polymyxins, a group of cationic antimicrobial polypeptides, act as a last-resort defense against lethal infections by carbapenem-resistant Gram-negative pathogens. Recent emergence and fast spread of mobilized colistin resistance determinant mcr-1 argue the renewed interest of colistin in clinical therapies, threatening global public health and agriculture production. This mini-review aims to present an updated overview of mcr-1, covering its global dissemination, the diversity of its hosts/plasmid reservoirs, the complexity in the genetic environment adjacent to mcr-1, the appearance of new mcr-like genes, and the molecular mechanisms for mobilized colistin resistance determinant 1/2 (MCR-1/2).

Molecular markers for genetic diversity and phylogeny research of ...

African Journals Online (AJOL)

Brazilian sheep descended from several breeds brought to the New World by Portuguese and Spanish colonists, and they have evolved and adapted to local climatic variations and acquired tolerance or resistance to many diseases. Molecular markers are widely used in analyzing genetic variability, and markers such as ...

Cytogenetics and molecular genetics of Wilms' tumor of childhood

NARCIS (Netherlands)

Slater, R. M.; Mannens, M. M.

1992-01-01

We describe the way in which application of cytogenetic and molecular genetic techniques to the study of Wilms' tumor (WT) of the kidney and the associated congenital disorders, such as sporadic aniridia and the Beckwith-Wiedemann syndrome, has led to identification of two regions on the short arm

MOLECULAR-GENETIC BASIS OF HIGHER PLANTS TOLERANCE TO, AND ACCUMULATION OF, CADMIUM

Directory of Open Access Journals (Sweden)

Olga A Kulaeva

2010-09-01

Full Text Available Cadmium (Cd is one of the most wide-ranged and dangerous pollutants for all living organisms, including plants. At present time the intensive studies of mechanisms of Cd accumulation in plant tissues and plant tolerance to its toxic influence are performed. Data about variation of Cd tolerance and accumulation traits in natural populations of hyperaccumulators species as well as important crops were obtained. A series of mutants with changed sensitivity to Cd was obtained. In recent decade several classes of proteins involving in cell responses to Cd ions were revealed. An important role of microRNA in plant adaptation to Cd was recently demonstrated. Studies of molecular-genetic mechanisms of Cd accumulation and plant tolerance to it are theoretical basis for development of phytoremediation technologies of soil contaminated with heavy metals and breeding of crop varieties with decreased Cd accumulation.

MEGA X: Molecular Evolutionary Genetics Analysis across Computing Platforms.

Science.gov (United States)

Kumar, Sudhir; Stecher, Glen; Li, Michael; Knyaz, Christina; Tamura, Koichiro

2018-06-01

The Molecular Evolutionary Genetics Analysis (Mega) software implements many analytical methods and tools for phylogenomics and phylomedicine. Here, we report a transformation of Mega to enable cross-platform use on Microsoft Windows and Linux operating systems. Mega X does not require virtualization or emulation software and provides a uniform user experience across platforms. Mega X has additionally been upgraded to use multiple computing cores for many molecular evolutionary analyses. Mega X is available in two interfaces (graphical and command line) and can be downloaded from www.megasoftware.net free of charge.

Genética molecular: avanços e problemas Molecular genetics: advances and problems

Directory of Open Access Journals (Sweden)

Eloi S. Garcia

1996-03-01

Full Text Available Este artigo traz a discussão sobre genética molecular em saúde ao campo da saúde pública. Com a revolução produzida pela chegada da engenharia genética, é importante discutir alguns dos avanços e problemas desta tecnologia para a sociedade. Está na hora de se fazer uma avaliação clara e bem informada acerca do que já se conseguiu e do que ainda podemos conseguir através desta tecnologia. A sociedade precisa compreender as implicações éticas e práticas de uma tecnologia capaz de produzir drogas milagrosas, dagnósticos modernos e a cura de todas as doenças. Alguns pontos particularmente delicados pertinentes às questões sociais ligadas à biologia molecular e ao projeto genoma humano são discutidos.This article is an attempt to draw the discussion on molecular genetics in health into the public health domain. Now that the genetic engineering revolution has arrived, it is important to point out the advances and problems this technology poses for society. It is time for a clear, informed assessment of what we have already achieved and may soon achieve using this technology. Clearly, society needs to understand the ethical and practical implications of a technology which can produce miracle drugs and modern diagnoses and cure virtually every disease. Important points from sensitive social issues raised by molecular biology and the human genome project are discussed.

Prediction of mechanical properties for hexagonal boron nitride nanosheets using molecular mechanics model

Energy Technology Data Exchange (ETDEWEB)

Natsuki, Toshiaki [Shinshu University, Faculty of Textile Science and Technology, Ueda (Japan); Shinshu University, Institute of Carbon Science and Technology, Nagano (Japan); Natsuki, Jun [Shinshu University, Institute of Carbon Science and Technology, Nagano (Japan)

2017-04-15

Mechanical behaviors of nanomaterials are not easy to be evaluated in the laboratory because of their extremely small size and difficulty controlling. Thus, a suitable model for the estimation of the mechanical properties for nanomaterials becomes very important. In this study, the elastic properties of boron nitride (BN) nanosheets, including the elastic modulus, the shear modulus, and the Poisson's ratio, are predicted using a molecular mechanics model. The molecular mechanics force filed is established to directly incorporate the Morse potential function into the constitutive model of nanostructures. According to the molecular mechanics model, the chirality effect of hexagonal BN nanosheets on the elastic modulus is investigated through a closed-form solution. The simulated result shows that BN nanosheets exhibit an isotropic elastic property. The present analysis yields a set of very simple formulas and is able to be served as a good approximation on the mechanical properties for the BN nanosheets. (orig.)

Prediction of mechanical properties for hexagonal boron nitride nanosheets using molecular mechanics model

International Nuclear Information System (INIS)

Natsuki, Toshiaki; Natsuki, Jun

2017-01-01

Mechanical behaviors of nanomaterials are not easy to be evaluated in the laboratory because of their extremely small size and difficulty controlling. Thus, a suitable model for the estimation of the mechanical properties for nanomaterials becomes very important. In this study, the elastic properties of boron nitride (BN) nanosheets, including the elastic modulus, the shear modulus, and the Poisson's ratio, are predicted using a molecular mechanics model. The molecular mechanics force filed is established to directly incorporate the Morse potential function into the constitutive model of nanostructures. According to the molecular mechanics model, the chirality effect of hexagonal BN nanosheets on the elastic modulus is investigated through a closed-form solution. The simulated result shows that BN nanosheets exhibit an isotropic elastic property. The present analysis yields a set of very simple formulas and is able to be served as a good approximation on the mechanical properties for the BN nanosheets. (orig.)

Isolation and molecular genetic characterization of a yeast strain ...

African Journals Online (AJOL)

The yeast was identified by molecular genetics technique based on sequence analysis of the variable D1/D2 domain of the large subunit (26S) ribosomal DNA. Subsequent 26S rRNA gene sequencing showed 100% base sequence homology and it was identified as Candida viswanathii. The degradation of PAHs

Molecular mechanisms of induced pluripotency.

Science.gov (United States)

Kulcenty, Katarzyna; Wróblewska, Joanna; Mazurek, Sylwia; Liszewska, Ewa; Jaworski, Jacek

2015-01-01

Growing knowledge concerning transcriptional control of cellular pluripotency has led to the discovery that the fate of differentiated cells can be reversed, which has resulted in the generation, by means of genetic manipulation, of induced pluripotent stem cells. Overexpression of just four pluripotency-related transcription factors, namely Oct3/4, Sox2, Klf4, and c-Myc (Yamanaka factors, OKSM), in fibroblasts appears sufficient to produce this new cell type. Currently, we know that these factors induce several changes in genetic program of differentiated cells that can be divided in two general phases: the initial one is stochastic, and the subsequent one is highly hierarchical and organised. This review briefly discusses the molecular events leading to induction of pluripotency in response to forced presence of OKSM factors in somatic cells. We also discuss other reprogramming strategies used thus far as well as the advantages and disadvantages of laboratory approaches towards pluripotency induction in different cell types.

The molecular genetics of inflammatory, autoimmune, and infectious diseases of the sinonasal tract: a review.

Science.gov (United States)

Montone, Kathleen T

2014-06-01

The sinonasal tract is frequently affected by a variety of nonneoplastic inflammatory disease processes that are often multifactorial in their etiology but commonly have a molecular genetic component. To review the molecular genetics of a variety of nonneoplastic inflammatory diseases of the sinonasal tract. Inflammatory lesions of the sinonasal tract can be divided into 3 main categories: (1) chronic rhinosinusitis, (2) infectious diseases, and (3) autoimmune diseases/vasculitides. The molecular diagnosis and pathways of a variety of these inflammatory lesions are currently being elucidated and will shed light on disease pathogenesis and treatment. The sinonasal tract is frequently affected by inflammatory lesions that arise through complex interactions of environmental, infectious, and genetic factors. Because these lesions are all inflammatory in nature, the molecular pathology surrounding them is most commonly due to upregulation and down-regulation of genes that affect inflammatory responses and immune regulation.

Genetic Diversity Analysis of Tagetes Species Using PCR Based Molecular Markers

International Nuclear Information System (INIS)

Shahzadi, I.; Ahmad, R.; Waheed, U.; Shah, M. F.

2016-01-01

Tagetes is a genus of medicinally important wild and cultivated plants containing several chemical compounds. Lack of information on variation at molecular level present in Tagetes species is paramount to understand the genetic basis of medicinally important compounds. Current study aims at finding genetic variability in Tagetes species using random and specific molecular markers. Two primer systems including 25 RAPD and 3 STS (limonene gene) were used to ascertain genetic diversity of 15 Tagetes genotypes belonging to different species. We found that 20 of the 25 tested RAPD primers generated stable band patterns with 167 loci of amplification products. The proportion of polymorphic bands was 95.21 percent for RAPD primers. Three STS primers generated a total of 29 amplification products, of which 96.55 percent were polymorphic. Homology of genotypes was 53.18 percent and 51.11 percent with RAPD and STS primers respectively. The dendrogram obtained revealed that the range of overall genetic distances estimated was 22 percent to 100 percent through RAPD and 9 percent to 100 percent through STS markers. The findings help to establish that PCR-based assay such as RAPD and STS could be used successfully for estimation of genetic diversity of different genotypes of Tagetes that can be used for selection of parents for improvement of the species. (author)

Molecular genetic identification of some wheat cultivars in the sudan

International Nuclear Information System (INIS)

Mekki, I. I; El Amin, H. B.

2002-01-01

Four wheat (Triticum aestivum L.) cultivars, namely condor, El-Nellene, Wadi El Neil and Debeira were characterized on biochemical and molecular bases. The biochemical ones were protein-banding patterns, using sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and isozymes to identify the biochemical genetic fingerprint of the four cultivars. Water-soluble protein-banding pattern showed no polymorphisms among the tested cultivars. The data from starch gel electrophoresis of enzymes, malate dehydrogenase (MDH), esterase (EST) and acid phosphate (ACPH) showed that the cultivars are monomorphic. Further trials to identify the molecular genetic fingerprints of the studied cultivars were carried out using RAPD-PCR twenty-five primers were tested to perform. RAPD-PCR analysis. From the PCR products, a phylogenetic map, i.e, dendrogram, was constructed for the studied cultivars which depicted tow groups. The first group contained Wadi El Neil and Deberia with 48.4% similarity, and the second group contained Condor and El Neileen with 100% similarity. There was no similarity between Condor and Debeira (100% dissimilarity). Therefor, these data can be used subsequently for genetic engineering research and for wheat breeding programmes in the Sudan.(Author)

Quality control in mutation analysis: the European Molecular Genetics Quality Network (EMQN).

Science.gov (United States)

Müller, C R

2001-08-01

The demand for clinical molecular genetics testing has steadily grown since its introduction in the 1980s. In order to reach and maintain the agreed quality standards of laboratory medicine, the same internal and external quality assurance (IQA/EQA) criteria have to be applied as for "conventional" clinical chemistry or pathology. In 1996 the European Molecular Genetics Quality Network (EMQN) was established in order to spread QA standards across Europe and to harmonise the existing national activities. EMQN is operated by a central co-ordinator and 17 national partners from 15 EU countries; since 1998 it is being funded by the EU commission for a 3-year period. EMQN promotes QA by two tools: by providing disease-specific best practice meetings (BPM) and EQA schemes. A typical BPM is focussed on one disease or group of related disorders. International experts report on the latest news of gene characterisation and function and the state-of-the-art techniques for mutation detection. Disease-specific EQA schemes are provided by experts in the field. DNA samples are sent out together with mock clinical referrals and a diagnostic question is asked. Written reports must be returned which are marked for genotyping and interpretation. So far, three BPMs have been held and six EQA schemes are in operation at various stages. Although mutation types and diagnostic techniques varied considerably between schemes, the overall technical performance showed a high diagnostic standard. Nevertheless, serious genotyping errors have been occurred in some schemes which underline the necessity of quality assurance efforts. The European Molecular Genetics Quality Network provides a necessary platform for the internal and external quality assurance of molecular genetic testing.

Mini-review: Molecular mechanisms of antifouling compounds

KAUST Repository

Qian, Pei-Yuan

2013-04-01

Various antifouling (AF) coatings have been developed to protect submerged surfaces by deterring the settlement of the colonizing stages of fouling organisms. A review of the literature shows that effective AF compounds with specific targets are ones often considered non-toxic. Such compounds act variously on ion channels, quorum sensing systems, neurotransmitters, production/release of adhesive, and specific enzymes that regulate energy production or primary metabolism. In contrast, AF compounds with general targets may or may not act through toxic mechanisms. These compounds affect a variety of biological activities including algal photosynthesis, energy production, stress responses, genotoxic damage, immunosuppressed protein expression, oxidation, neurotransmission, surface chemistry, the formation of biofilms, and adhesive production/release. Among all the targets, adhesive production/release is the most common, possibly due to a more extensive research effort in this area. Overall, the specific molecular targets and the molecular mechanisms of most AF compounds have not been identified. Thus, the information available is insufficient to draw firm conclusions about the types of molecular targets to be used as sensitive biomarkers for future design and screening of compounds with AF potential. In this review, the relevant advantages and disadvantages of the molecular tools available for studying the molecular targets of AF compounds are highlighted briefly and the molecular mechanisms of the AF compounds, which are largely a source of speculation in the literature, are discussed. © 2013 Copyright Taylor and Francis Group, LLC.

Reliable prediction of adsorption isotherms via genetic algorithm molecular simulation.

Science.gov (United States)

LoftiKatooli, L; Shahsavand, A

2017-01-01

Conventional molecular simulation techniques such as grand canonical Monte Carlo (GCMC) strictly rely on purely random search inside the simulation box for predicting the adsorption isotherms. This blind search is usually extremely time demanding for providing a faithful approximation of the real isotherm and in some cases may lead to non-optimal solutions. A novel approach is presented in this article which does not use any of the classical steps of the standard GCMC method, such as displacement, insertation, and removal. The new approach is based on the well-known genetic algorithm to find the optimal configuration for adsorption of any adsorbate on a structured adsorbent under prevailing pressure and temperature. The proposed approach considers the molecular simulation problem as a global optimization challenge. A detailed flow chart of our so-called genetic algorithm molecular simulation (GAMS) method is presented, which is entirely different from traditions molecular simulation approaches. Three real case studies (for adsorption of CO 2 and H 2 over various zeolites) are borrowed from literature to clearly illustrate the superior performances of the proposed method over the standard GCMC technique. For the present method, the average absolute values of percentage errors are around 11% (RHO-H 2 ), 5% (CHA-CO 2 ), and 16% (BEA-CO 2 ), while they were about 70%, 15%, and 40% for the standard GCMC technique, respectively.

Molecular genetics: Step by step implementation in maize breeding

Directory of Open Access Journals (Sweden)

Konstantinov Kosana

2007-01-01

Full Text Available Efficiency in plant breeding is determined primarily by the ability to screen for genetic polymorphism, productivity and yield stability early in program. Dependent on the knowledge about the biochemical bases of the trait and nature of its genetic control, trait could be modified either through mutagenesis of genes controlling it or through the transfer of already existing mutant genes, controlling desired trait to different plant genotypes by classic crossing. Objective of this report is to present partly results on the investigation of the possibilities to apply ionizing radiations (fast neutrons, γ -rays and chemical mutagens (EI, iPMS, EMS, ENU to get maize and wheat mutants with increased amount and improved protein quality. Besides this approach in mutation breeding, results on the very early investigation of biochemical background of opaque -2 mutation including use of coupled cell - free RNA and protein synthesis containing components from both wild and opaque - 2 maize genotypes (chromatin, RNA polymerase, microsomall fraction, protein bodies will be presented. Partial results on opaque - 2 gene incorporation in different genetic background are reviewed. Part of report is dealing with different classes of molecular markers (proteins, RFLP, AFLP, RAPD, and SSR application in maize genome polymorphism investigation. Besides application of different molecular markers classes in the investigation of heterosis phenomena they are useful in biochemical pathway of important traits control determination as well. .

Genetic alterations in hepatocellular carcinoma: An update

Science.gov (United States)

Niu, Zhao-Shan; Niu, Xiao-Jun; Wang, Wen-Hong

2016-01-01

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. Although recent advances in therapeutic approaches for treating HCC have improved the prognoses of patients with HCC, this cancer is still associated with a poor survival rate mainly due to late diagnosis. Therefore, a diagnosis must be made sufficiently early to perform curative and effective treatments. There is a need for a deeper understanding of the molecular mechanisms underlying the initiation and progression of HCC because these mechanisms are critical for making early diagnoses and developing novel therapeutic strategies. Over the past decade, much progress has been made in elucidating the molecular mechanisms underlying hepatocarcinogenesis. In particular, recent advances in next-generation sequencing technologies have revealed numerous genetic alterations, including recurrently mutated genes and dysregulated signaling pathways in HCC. A better understanding of the genetic alterations in HCC could contribute to identifying potential driver mutations and discovering novel therapeutic targets in the future. In this article, we summarize the current advances in research on the genetic alterations, including genomic instability, single-nucleotide polymorphisms, somatic mutations and deregulated signaling pathways, implicated in the initiation and progression of HCC. We also attempt to elucidate some of the genetic mechanisms that contribute to making early diagnoses of and developing molecularly targeted therapies for HCC. PMID:27895396

[Advance in molecular biology of Dendrobium (Orchidaceae)].

Science.gov (United States)

Li, Qing; Li, Biao; Guo, Shun-Xing

2016-08-01

With the development of molecular biology, the process in molecular biology research of Dendrobium is going fast. Not only did it provide new ways to identify Dendrobium quickly, reveal the genetic diversity and relationship of Dendrobium, but also lay the vital foundation for explaining the mechanism of Dendrobium growth and metabolism. The present paper reviews the recent process in molecular biology research of Dendrobium from three aspects, including molecular identification, genetic diversity and functional genes. And this review will facilitate the development of this research area and Dendrobium. Copyright© by the Chinese Pharmaceutical Association.

Biological Applications of Hybrid Quantum Mechanics/Molecular Mechanics Calculation

Directory of Open Access Journals (Sweden)

Jiyoung Kang

2012-01-01

Full Text Available Since in most cases biological macromolecular systems including solvent water molecules are remarkably large, the computational costs of performing ab initio calculations for the entire structures are prohibitive. Accordingly, QM calculations that are jointed with MM calculations are crucial to evaluate the long-range electrostatic interactions, which significantly affect the electronic structures of biological macromolecules. A UNIX-shell-based interface program connecting the quantum mechanics (QMs and molecular mechanics (MMs calculation engines, GAMESS and AMBER, was developed in our lab. The system was applied to a metalloenzyme, azurin, and PU.1-DNA complex; thereby, the significance of the environmental effects on the electronic structures of the site of interest was elucidated. Subsequently, hybrid QM/MM molecular dynamics (MD simulation using the calculation system was employed for investigation of mechanisms of hydrolysis (editing reaction in leucyl-tRNA synthetase complexed with the misaminoacylated tRNALeu, and a novel mechanism of the enzymatic reaction was revealed. Thus, our interface program can play a critical role as a powerful tool for state-of-the-art sophisticated hybrid ab initio QM/MM MD simulations of large systems, such as biological macromolecules.

The impact of advances in human molecular biology on radiation genetic risk estimation in man

International Nuclear Information System (INIS)

Sankaranarayanan, K.

1996-01-01

This paper provides an overview of the conceptual framework, the data base, methods and assumptions used thus far to assess the genetic risks of exposure of human populations to ionising radiation. These are then re-examined in the contemporary context of the rapidly expanding knowledge of the molecular biology of human mendelian diseases. This re-examination reveals that (i) many of the assumptions used thus far in radiation genetic risk estimation may not be fully valid and (ii) the current genetic risk estimates are probably conservative, but provide an adequate margin of safety for radiological protection. The view is expressed that further advances in the field of genetic risk estimation will be largely driven by advances in the molecular biology of human genetic diseases. (author). 37 refs., 5 tabs

Quantum Mechanics/Molecular Mechanics Study of the Sialyltransferase Reaction Mechanism.

Science.gov (United States)

Hamada, Yojiro; Kanematsu, Yusuke; Tachikawa, Masanori

2016-10-11

The sialyltransferase is an enzyme that transfers the sialic acid moiety from cytidine 5'-monophospho-N-acetyl-neuraminic acid (CMP-NeuAc) to the terminal position of glycans. To elucidate the catalytic mechanism of sialyltransferase, we explored the potential energy surface along the sialic acid transfer reaction coordinates by the hybrid quantum mechanics/molecular mechanics method on the basis of the crystal structure of sialyltransferase CstII. Our calculation demonstrated that CstII employed an S N 1-like reaction mechanism via the formation of a short-lived oxocarbenium ion intermediate. The computational barrier height was 19.5 kcal/mol, which reasonably corresponded with the experimental reaction rate. We also found that two tyrosine residues (Tyr156 and Tyr162) played a vital role in stabilizing the intermediate and the transition states by quantum mechanical interaction with CMP.

Atomistic insight into the catalytic mechanism of glycosyltransferases by combined quantum mechanics/molecular mechanics (QM/MM) methods.

Science.gov (United States)

Tvaroška, Igor

2015-02-11

Glycosyltransferases catalyze the formation of glycosidic bonds by assisting the transfer of a sugar residue from donors to specific acceptor molecules. Although structural and kinetic data have provided insight into mechanistic strategies employed by these enzymes, molecular modeling studies are essential for the understanding of glycosyltransferase catalyzed reactions at the atomistic level. For such modeling, combined quantum mechanics/molecular mechanics (QM/MM) methods have emerged as crucial. These methods allow the modeling of enzymatic reactions by using quantum mechanical methods for the calculation of the electronic structure of the active site models and treating the remaining enzyme environment by faster molecular mechanics methods. Herein, the application of QM/MM methods to glycosyltransferase catalyzed reactions is reviewed, and the insight from modeling of glycosyl transfer into the mechanisms and transition states structures of both inverting and retaining glycosyltransferases are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Baseline Algorithm for Molecular Diagnosis of Genetic Eye Diseases: Ophthalmologist’s Perspective

Directory of Open Access Journals (Sweden)

Hande Taylan Şekeroğlu

2016-12-01

Full Text Available To the Editor: Genetic eye diseases constitute a large and heterogeneous group. Individual diseases may cause multiple structural/functional anomalies and developmental features. Family history may be suggestive; however, it may also be challenging, particularly in late-onset conditions or in cases of variable expression. In the current era of genetic advances, diagnosis of a genetic eye disease is facilitated by well-established collaboration between ophthalmologists and geneticists, as increasingly more patients will be asking for genetic counseling and prenatal diagnosis in addition to ophthalmologic management. Molecular investigation of a genetic eye disease requires customized analysis and advanced technology in addition to the requisite detailed family history and accurate ophthalmological diagnosis. A common indication for genetic testing is the validation of a preliminary diagnosis made in clinical practice. The need to determine the prognostic implications of the genotype, assessment of the recurrence risk and in particular, the possibility of specific gene therapy in the near future encourages clinicians to pursue genetic research. We present here a baseline algorithm covering common genetic mechanisms in order to outline a basic molecular approach for ophthalmologists. The first step of the flow chart, a prudent clinical examination with complete description of the phenotype, is indispensible for making a precise and accurate preliminary diagnosis (Figure 1. If the phenotype is pathognomonic, Sanger sequencing is preferred for confirmation.1 A previously established genotype-phenotype correlation may add to the value, either by providing accurate prognostic information or by indicating which particular mutation to look for. One such example may be electroretinographic supranormal rod response, indicating KCNV2 mutation type cone dystrophy, which can be precisely detected by Sanger sequencing or qPCR.2 Conventional karyotyping reveals

Generation of Compliant Mechanisms using Hybrid Genetic Algorithm

Science.gov (United States)

Sharma, D.; Deb, K.

2014-10-01

Compliant mechanism is a single piece elastic structure which can deform to perform the assigned task. In this work, compliant mechanisms are evolved using a constraint based bi-objective optimization formulation which requires one user defined parameter ( η). This user defined parameter limits a gap between a desired path and an actual path traced by the compliant mechanism. The non-linear and discrete optimization problems are solved using the hybrid Genetic Algorithm (GA) wherein domain specific initialization, two-dimensional crossover operator and repairing techniques are adopted. A bit-wise local search method is used with elitist non-dominated sorting genetic algorithm to further refine the compliant mechanisms. Parallel computations are performed on the master-slave architecture to reduce the computation time. A parametric study is carried out for η value which suggests a range to evolve topologically different compliant mechanisms. The applied and boundary conditions to the compliant mechanisms are considered the variables that are evolved by the hybrid GA. The post-analysis of results unveils that the complaint mechanisms are always supported at unique location that can evolve the non-dominated solutions.

ParFit: A Python-Based Object-Oriented Program for Fitting Molecular Mechanics Parameters to ab Initio Data.

Science.gov (United States)

Zahariev, Federico; De Silva, Nuwan; Gordon, Mark S; Windus, Theresa L; Dick-Perez, Marilu

2017-03-27

A newly created object-oriented program for automating the process of fitting molecular-mechanics parameters to ab initio data, termed ParFit, is presented. ParFit uses a hybrid of deterministic and stochastic genetic algorithms. ParFit can simultaneously handle several molecular-mechanics parameters in multiple molecules and can also apply symmetric and antisymmetric constraints on the optimized parameters. The simultaneous handling of several molecules enhances the transferability of the fitted parameters. ParFit is written in Python, uses a rich set of standard and nonstandard Python libraries, and can be run in parallel on multicore computer systems. As an example, a series of phosphine oxides, important for metal extraction chemistry, are parametrized using ParFit. ParFit is in an open source program available for free on GitHub ( https://github.com/fzahari/ParFit ).

76 FR 6623 - Molecular and Clinical Genetics Panel of the Medical Devices Advisory Committee; Notice of Meeting

Science.gov (United States)

2011-02-07

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2011-N-0066] Molecular and Clinical Genetics Panel of the Medical Devices Advisory Committee; Notice of Meeting AGENCY... public. Name of Committee: Molecular and Clinical Genetics Panel of the Medical Devices Advisory...

Molecular and genetic epidemiology of cancer in low- and medium-income countries.

Science.gov (United States)

Malhotra, Jyoti

2014-01-01

Genetic and molecular factors can play an important role in an individual's cancer susceptibility and response to carcinogen exposure. Cancer susceptibility and response to carcinogen exposure can be either through inheritance of high penetrance but rare germline mutations that constitute heritable cancer syndromes, or it can be inherited as common genetic variations or polymorphisms that are associated with low to moderate risk for development of cancer. These polymorphisms can interact with environmental exposures and can influence an individual's cancer risk through multiple pathways, including affecting the rate of metabolism of carcinogens or the immune response to these toxins. Thus, these genetic polymorphisms can account for some of the geographical differences seen in cancer prevalence between different populations. This review explores the role of molecular epidemiology in the field of cancer prevention and control in low- and medium-income countries. Using data from Human Genome Project and HapMap Project, genome-wide association studies have been able to identify multiple susceptibility loci for different cancers. The field of genetic and molecular epidemiology has been further revolutionized by the discovery of newer, faster, and more efficient DNA-sequencing technologies including next-generation sequencing. The new DNA-sequencing technologies can play an important role in planning and implementation of cancer prevention and screening strategies. More research is needed in this area, especially in investigating new biomarkers and measuring gene-environment interactions. Copyright © 2014 Icahn School of Medicine at Mount Sinai. Published by Elsevier Inc. All rights reserved.

Substrate binding and catalytic mechanism in phospholipase C from Bacillus cereus. a molecular mechanics and molecular dynamics study

DEFF Research Database (Denmark)

da Graça Thrige, D; Buur, J R; Jørgensen, Flemming Steen

1997-01-01

cereus including a docked substrate molecule was subjected to a stepwise molecular mechanics energy minimization. Second, the location of the nucleophilic water molecule in the active site of the fully relaxed enzyme-substrate complex was determined by evaluation of nonbonded interaction energies between...... water molecule was verified during a 100 ps molecular dynamics simulation. During the simulation the substrate undergoes a conformational change, but retains its localization in the active site. The contacts between the enzyme, the substrate, and the nucleophilic water molecule display some fluctuations...... the strong electrostatic interactions in the active site realistically during energy minimization, delocalization of the charges from the three zinc ions was considered. Therefore, quantum mechanics calculations on the zinc ions and the zinc-coordinating residues were carried out prior to the molecular...

Genetics and molecular biology of hypotension

Science.gov (United States)

Robertson, D.

1994-01-01

Major strides in the molecular biology of essential hypertension are currently underway. This has tended to obscure the fact that a number of inherited disorders associated with low blood pressure exist and that these diseases may have milder and underrecognized phenotypes that contribute importantly to blood pressure variation in the general population. This review highlights some of the gene products that, if abnormal, could cause hypotension in some individuals. Diseases due to abnormalities in the catecholamine enzymes are discussed in detail. It is likely that genetic abnormalities with hypotensive phenotypes will be as interesting and diverse as those that give rise to hypertensive disorders.

Simulation with quantum mechanics/molecular mechanics for drug discovery.

Science.gov (United States)

Barbault, Florent; Maurel, François

2015-10-01

Biological macromolecules, such as proteins or nucleic acids, are (still) molecules and thus they follow the same chemical rules that any simple molecule follows, even if their size generally renders accurate studies unhelpful. However, in the context of drug discovery, a detailed analysis of ligand association is required for understanding or predicting their interactions and hybrid quantum mechanics/molecular mechanics (QM/MM) computations are relevant tools to help elucidate this process. In this review, the authors explore the use of QM/MM for drug discovery. After a brief description of the molecular mechanics (MM) technique, the authors describe the subtractive and additive techniques for QM/MM computations. The authors then present several application cases in topics involved in drug discovery. QM/MM have been widely employed during the last decades to study chemical processes such as enzyme-inhibitor interactions. However, despite the enthusiasm around this area, plain MM simulations may be more meaningful than QM/MM. To obtain reliable results, the authors suggest fixing several keystone parameters according to the underlying chemistry of each studied system.

Genetic anaylsis of a disease resistance gene from loblolly pine

Science.gov (United States)

Yinghua Huang; Nili Jin; Alex Diner; Chuck Tauer; Yan Zhang; John Damicone

2003-01-01

Rapid advances in molecular genetics provide great opportunities for studies of host defense mechanisms. Examination of plant responses to disease at the cellular and molecular level permits both discovery of changes in gene expression in the tissues attacked by pathogens, and identification of genetic components involved in the interaction between host and pathogens....

Genetic influences on attention deficit hyperactivity disorder symptoms from age 2 to 3: A quantitative and molecular genetic investigation

Directory of Open Access Journals (Sweden)

Saudino Kimberly J

2010-12-01

Full Text Available Abstract Background A twin study design was used to assess the degree to which additive genetic variance influences ADHD symptom scores across two ages during infancy. A further objective in the study was to observe whether genetic association with a number of candidate markers reflects results from the quantitative genetic analysis. Method We have studied 312 twin pairs at two time-points, age 2 and age 3. A composite measure of ADHD symptoms from two parent-rating scales: The Child Behavior Checklist/1.5 - 5 years (CBCL hyperactivity scale and the Revised Rutter Parent Scale for Preschool Children (RRPSPC was used for both quantitative and molecular genetic analyses. Results At ages 2 and 3 ADHD symptoms are highly heritable (h2 = 0.79 and 0.78, respectively with a high level of genetic stability across these ages. However, we also observe a significant level of genetic change from age 2 to age 3. There are modest influences of non-shared environment at each age independently (e2 = 0.22 and 0.21, respectively, with these influences being largely age-specific. In addition, we find modest association signals in DAT1 and NET1 at both ages, along with suggestive specific effects of 5-HTT and DRD4 at age 3. Conclusions ADHD symptoms are heritable at ages 2 and 3. Additive genetic variance is largely shared across these ages, although there are significant new effects emerging at age 3. Results from our genetic association analysis reflect these levels of stability and change and, more generally, suggest a requirement for consideration of age-specific genotypic effects in future molecular studies.

Molecular Genetic Identification Of Some Flax Mutants

International Nuclear Information System (INIS)

AMER, I.M.; MOUSTAFA, H.A.M.

2009-01-01

Five flax genotypes (Linum usitatissimum L.) i.e., commercial cultivar Sakha 2, the mother variety Giza 4 and three mutant types induced by gamma rays, were screened for their salinity tolerance in field experiments (salinity concentration was 8600 and 8300 ppm for soil and irrigation water, respectively). Mutation 6 was the most salt tolerant as compared to the other four genotypes.RAPD technique was used to detect some molecular markers associated with salt tolerance in flax (Mut 6), RAPD-PCR results using 12 random primers exhibited 149 amplified fragments; 91.9% of them were polymorphic and twelve molecular markers (8.1%) for salt tolerant (mutant 6) were identified with molecular size ranged from 191 to 4159 bp and only eight primers successes to amplify these specific markers. Concerning the other mutants, Mut 15 and Mut 25 exhibited 4.3% and 16.2% specific markers, respectively. The induced mutants exhibited genetic similarity to the parent variety were about 51%, 58.3% and 61.1% for Mut 25, Mut 6 and Mut 15, respectively. These specific markers (SM) are used for identification of the induced mutations and it is important for new variety registration.

Genetic studies and a search for molecular markers that are linked ...

African Journals Online (AJOL)

SERVER

Instead, linkage analysis resulted in the construction of a molecular marker linkage map consisting of 45 ..... This limits the application of this marker type, particularly in ... primer design when one uses RAPDs. .... Concepts of Genetics. Fourth.

[The genetics of addictions].

Science.gov (United States)

Ibañez Cuadrado, Angela

2008-01-01

The addictions are common chronic psychiatric diseases which represent a serious worldwide public-health problem. They have a high prevalence and negative effects at individual, family and societal level, with a high sanitary cost. Epidemiological genetic research has revealed that addictions are moderately to highly heritable. Also the investigation has evidenced that environmental and genetic factors contribute to individual differences in vulnerability to addictions. Advances in the neurobiology of addiction joined to the development of new molecular genetic technologies, have led to the identification of a variety of underlying genes and pathways in addiction process, leading to the description of common molecular mechanisms in substance and behaviour dependencies. Identifying gene-environment interactions is a crucial issue in future research. Other major goal in genetic research is the identification of new therapeutic targets for treatment and prevention.

Advance of Mechanically Controllable Break Junction for Molecular Electronics.

Science.gov (United States)

Wang, Lu; Wang, Ling; Zhang, Lei; Xiang, Dong

2017-06-01

Molecular electronics stands for the ultimate size of functional elements, keeping up with an unstoppable trend over the past few decades. As a vital component of molecular electronics, single molecular junctions have attracted significant attention from research groups all over the world. Due to its pronounced superiority, the mechanically controllable break junctions (MCBJ) technique has been widely applied to characterize the dynamic performance of single molecular junctions. This review presents a system analysis for single-molecule junctions and offers an overview of four test-beds for single-molecule junctions, thus offering more insight into the mechanisms of electron transport. We mainly focus on the development of state-of-the-art mechanically controlled break junctions. The three-terminal gated MCBJ approaches are introduced to manipulate the electron transport of molecules, and MCBJs are combined with characterization techniques. Additionally, applications of MCBJs and remarkable properties of single molecules are addressed. Finally, the challenges and perspective for the mechanically controllable break junctions technique are provided.

Understanding the molecular mechanisms of human microtia via a pig model of HOXA1 syndrome

Directory of Open Access Journals (Sweden)

Ruimin Qiao

2015-06-01

Full Text Available Microtia is a congenital malformation of the outer ears. Although both genetic and environmental components have been implicated in microtia, the genetic causes of this innate disorder are poorly understood. Pigs have naturally occurring diseases comparable to those in humans, providing exceptional opportunity to dissect the molecular mechanism of human inherited diseases. Here we first demonstrated that a truncating mutation in HOXA1 causes a monogenic disorder of microtia in pigs. We further performed RNA sequencing (RNA-Seq analysis on affected and healthy pig embryos (day 14.25. We identified a list of 337 differentially expressed genes (DEGs between the normal and mutant samples, shedding light on the transcriptional network involving HOXA1. The DEGs are enriched in biological processes related to cardiovascular system and embryonic development, and neurological, renal and urological diseases. Aberrant expressions of many DEGs have been implicated in human innate deformities corresponding to microtia-associated syndromes. After applying three prioritizing algorithms, we highlighted appealing candidate genes for human microtia from the 337 DEGs. We searched for coding variants of functional significance within six candidate genes in 147 microtia-affected individuals. Of note, we identified one EVC2 non-synonymous mutation (p.Asp1174Asn as a potential disease-implicating variant for a human microtia-associated syndrome. The findings advance our understanding of the molecular mechanisms underlying human microtia, and provide an interesting example of the characterization of human disease-predisposing variants using pig models.

Targeted Cancer Therapy: Vital Oncogenes and a New Molecular Genetic Paradigm for Cancer Initiation Progression and Treatment

Science.gov (United States)

Willis, Rudolph E.

2016-01-01

It has been declared repeatedly that cancer is a result of molecular genetic abnormalities. However, there has been no working model describing the specific functional consequences of the deranged genomic processes that result in the initiation and propagation of the cancer process during carcinogenesis. We no longer need to question whether or not cancer arises as a result of a molecular genetic defect within the cancer cell. The legitimate questions are: how and why? This article reviews the preeminent data on cancer molecular genetics and subsequently proposes that the sentinel event in cancer initiation is the aberrant production of fused transcription activators with new molecular properties within normal tissue stem cells. This results in the production of vital oncogenes with dysfunctional gene activation transcription properties, which leads to dysfunctional gene regulation, the aberrant activation of transduction pathways, chromosomal breakage, activation of driver oncogenes, reactivation of stem cell transduction pathways and the activation of genes that result in the hallmarks of cancer. Furthermore, a novel holistic molecular genetic model of cancer initiation and progression is presented along with a new paradigm for the approach to personalized targeted cancer therapy, clinical monitoring and cancer diagnosis. PMID:27649156

MOLECULAR MECHANISMS OF FEAR LEARNING AND MEMORY

Science.gov (United States)

Johansen, Joshua P.; Cain, Christopher K.; Ostroff, Linnaea E.; LeDoux, Joseph E.

2011-01-01

Pavlovian fear conditioning is a useful behavioral paradigm for exploring the molecular mechanisms of learning and memory because a well-defined response to a specific environmental stimulus is produced through associative learning processes. Synaptic plasticity in the lateral nucleus of the amygdala (LA) underlies this form of associative learning. Here we summarize the molecular mechanisms that contribute to this synaptic plasticity in the context of auditory fear conditioning, the form of fear conditioning best understood at the molecular level. We discuss the neurotransmitter systems and signaling cascades that contribute to three phases of auditory fear conditioning: acquisition, consolidation, and reconsolidation. These studies suggest that multiple intracellular signaling pathways, including those triggered by activation of Hebbian processes and neuromodulatory receptors, interact to produce neural plasticity in the LA and behavioral fear conditioning. Together, this research illustrates the power of fear conditioning as a model system for characterizing the mechanisms of learning and memory in mammals, and potentially for understanding fear related disorders, such as PTSD and phobias. PMID:22036561

Molecular mechanisms of fear learning and memory.

Science.gov (United States)

Johansen, Joshua P; Cain, Christopher K; Ostroff, Linnaea E; LeDoux, Joseph E

2011-10-28

Pavlovian fear conditioning is a particularly useful behavioral paradigm for exploring the molecular mechanisms of learning and memory because a well-defined response to a specific environmental stimulus is produced through associative learning processes. Synaptic plasticity in the lateral nucleus of the amygdala (LA) underlies this form of associative learning. Here, we summarize the molecular mechanisms that contribute to this synaptic plasticity in the context of auditory fear conditioning, the form of fear conditioning best understood at the molecular level. We discuss the neurotransmitter systems and signaling cascades that contribute to three phases of auditory fear conditioning: acquisition, consolidation, and reconsolidation. These studies suggest that multiple intracellular signaling pathways, including those triggered by activation of Hebbian processes and neuromodulatory receptors, interact to produce neural plasticity in the LA and behavioral fear conditioning. Collectively, this body of research illustrates the power of fear conditioning as a model system for characterizing the mechanisms of learning and memory in mammals and potentially for understanding fear-related disorders, such as PTSD and phobias. Copyright © 2011 Elsevier Inc. All rights reserved.

Molecular Mechanisms of Renal Ischemic Conditioning Strategies

DEFF Research Database (Denmark)

Kierulf-Lassen, Casper; Nieuwenhuijs-Moeke, Gertrude J; Krogstrup, Nicoline V

2015-01-01

summarizes research on the molecular mechanisms underlying both local and remote ischemic pre-, per- and postconditioning of the kidney. The different types of conditioning strategies in the kidney recruit similar powerful pro-survival mechanisms. Likewise, renal ischemic conditioning mobilizes many...

[Molecular biology of renal cancer: bases for genetic directed therapy in advanced disease].

Science.gov (United States)

Maroto Rey, José Pablo; Cillán Narvaez, Elena

2013-06-01

There has been expansion of therapeutic options in the management of metastatic renal cell carcinoma due to a better knowledge of the molecular biology of kidney cancers. There are different tumors grouped under the term renal cell carcinoma, being clear cell cancer the most frequent and accounting for 80% of kidney tumors. Mutations in the Von Hippel-Lindau gene can be identified in up to 80% of sporadic clear cell cancer, linking a genetically inheritable disease where vascular tumors are frequent, with renal cell cancer. Other histologic types present specific alterations in molecular pathways, like c-MET in papillary type I tumors, and Fumarase Hydratase in papillary type II tumors. Identification of the molecular alteration for a specific tumor may offer an opportunity for treatment selection based on biomarkers, and, in the future, for developing an engineering designed genetic treatment.

[Neonatal hyperbilirubinemia and molecular mechanisms of jaundice].

Science.gov (United States)

Jirsa, M; Sticová, E

2013-07-01

The introductory summarises the classical path of heme degradation and classification of jaundice. Subsequently, a description of neonatal types of jaundice is given, known as Crigler Najjar, Gilberts, DubinJohnson and Rotor syndromes, emphasising the explanation of the molecular mechanisms of these metabolic disorders. Special attention is given to a recently discovered molecular mechanism of the Rotor syndrome. The mechanism is based on the inability of the liver to retrospectively uptake the conjugated bilirubin fraction primarily excreted into the blood, not bile. A reduced ability of the liver to uptake the conjugated bilirubin contributes to the development of hyperbilirubinemia in common disorders of the liver and bile ducts and to the toxicity of xenobiotics and drugs using transport proteins for conjugated bilirubin.

Molecular marker studies in riverine buffaloes, for characterization and diagnosis of genetic defects

International Nuclear Information System (INIS)

Yadav, B.R.

2005-01-01

The buffalo is probably the last livestock species to have been domesticated, with many genetic, physiological and behavioural traits not yet well understood. Molecular markers have been used for characterizing animals and breeds, diagnosing diseases and identifying anatomical and physiological anomalies. RFLP studies showed low heterozygosity, but genomic and oligonucleotide probes showed species-specific bands useful for identification of carcass or other unknown samples. Use of RAPD revealed band frequencies, band sharing frequencies, genetic distances, and genetic and identity indexes in different breeds. Bovine microsatellite primers indicate that 70.9% of bovine loci were conserved in buffalo. Allele numbers, sizes, frequencies, heterozygosity and polymorphism information content showed breed-specific patterns. Different marker types - genomic and oligonucleotide probes, RAPD and microsatellites - are useful in parent identification. Individual specific DNA fingerprinting techniques were applied with twin-born animal (XX/XY) chimerism, sex identification, anatomically defective and XO individuals. Molecular markers are a potential tool for geneticists and breeders to evaluate existing germplasm and to manipulate it to develop character-specific strains and to provide the basis for effective genetic conservation. (author)

Permanent Genetic Resources added to Molecular Ecology Resources Database 1 December 2012 - 31 January 2013

Czech Academy of Sciences Publication Activity Database

Mendel, Jan; Urbánková, Soňa; Vyskočilová, M.

2013-01-01

Roč. 13, č. 3 (2013), s. 546-549 ISSN 1755-098X Institutional support: RVO:68081766 Keywords : genetic database * microsatellite marker loci Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.626, year: 2013

The molecular mechanisms of offspring effects from obese pregnancy.

LENUS (Irish Health Repository)

Dowling, Daniel

2013-01-01

The incidence of obesity, increased weight gain and the popularity of high-fat \\/ high-sugar diets are seriously impacting upon the global population. Billions of individuals are affected, and although diet and lifestyle are of paramount importance to the development of adult obesity, compelling evidence is emerging which suggests that maternal obesity and related disorders may be passed on to the next generation by non-genetic means. The processes acting within the uteri of obese mothers may permanently predispose offspring to a diverse plethora of diseases ranging from obesity and diabetes to psychiatric disorders. This review aims to summarise some of the molecular mechanisms and active processes currently known about maternal obesity and its effect on foetal and neonatal physiology and metabolism. Complex and multifactorial networks of molecules are intertwined and culminate in a pathologically synergistic manner to cause disruption and disorganisation of foetal physiology. This altered phenotype may potentiate the cycle of intergenerational transmission of obesity and related disorders.

The Molecular Mechanisms of Offspring Effects from Obese Pregnancy

Directory of Open Access Journals (Sweden)

Daniel Dowling

2013-04-01

Full Text Available The incidence of obesity, increased weight gain and the popularity of high-fat / high-sugar diets are seriously impacting upon the global population. Billions of individuals are affected, and although diet and lifestyle are of paramount importance to the development of adult obesity, compelling evidence is emerging which suggests that maternal obesity and related disorders may be passed on to the next generation by non-genetic means. The processes acting within the uteri of obese mothers may permanently predispose offspring to a diverse plethora of diseases ranging from obesity and diabetes to psychiatric disorders. This review aims to summarise some of the molecular mechanisms and active processes currently known about maternal obesity and its effect on foetal and neonatal physiology and metabolism. Complex and multifactorial networks of molecules are intertwined and culminate in a pathologically synergistic manner to cause disruption and disorganisation of foetal physiology. This altered phenotype may potentiate the cycle of intergenerational transmission of obesity and related disorders.

[Clinical genealogical and molecular genetic study of patients with mental retardation].

Science.gov (United States)

Hryshchenko, N V; B'ichkova, A M; Lyvshyts, A B; Kravchenko, S A; Pampukha, V N; Solov'ev, A A; Kucherenko, A M; Tatarskiĭ, P F; Afanas'eva, N A; Dubrovskaia, E V; Patskun, Ie Y; Zymak-Zakutnaia, N O; Nykytchina, T V; Lohysh, S Iu; Lyvshyts, L A

2012-01-01

The results of clinical, genealogical, cytogenetic and molecular genetic studies of 113 patients from 96 families with different forms of mental retardation from Ukraine are presented. This study was held as part of the CHERISH project of the 7-th Framework Program. The aim of the project is to improve diagnostics of mental retardation in children in Eastern Europe and Central Asia through detailed analysis of known chromosomal and gene's aberrations and to find the new gene-candidates that cause mental retardation. All patients have normal chromosome number (46XY or 46XX). The cases with fragile-X syndrome were eliminated using molecular genetic methods. Genome rearrangements were found among 28 patients using cytogenetic analysis, multiplex ligation-dependent probe amplification (MLPA analysis) ofsubtelomeric regions and array-based comparative genomic hybridisation (array CGH screening). In 10 cases known pathogenic CNV's were identified, 11 cases are unknown aberrations; their pathogenicity is being determined. The rest cases are known nonpathogenic gene rearrangements. Obtained results show the strong genetic heterogeneity of hereditary forms of mental retardation. The further studies will allow to identificate genes candidates and certain mutations in these genes that may be associated with this pathology.

Developmental psychopathology in an era of molecular genetics and neuroimaging: A developmental neurogenetics approach.

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Hyde, Luke W

2015-05-01

The emerging field of neurogenetics seeks to model the complex pathways from gene to brain to behavior. This field has focused on imaging genetics techniques that examine how variability in common genetic polymorphisms predict differences in brain structure and function. These studies are informed by other complimentary techniques (e.g., animal models and multimodal imaging) and have recently begun to incorporate the environment through examination of Imaging Gene × Environment interactions. Though neurogenetics has the potential to inform our understanding of the development of psychopathology, there has been little integration between principles of neurogenetics and developmental psychopathology. The paper describes a neurogenetics and Imaging Gene × Environment approach and how these approaches have been usefully applied to the study of psychopathology. Six tenets of developmental psychopathology (the structure of phenotypes, the importance of exploring mechanisms, the conditional nature of risk, the complexity of multilevel pathways, the role of development, and the importance of who is studied) are identified, and how these principles can further neurogenetics applications to understanding the development of psychopathology is discussed. A major issue of this piece is how neurogenetics and current imaging and molecular genetics approaches can be incorporated into developmental psychopathology perspectives with a goal of providing models for better understanding pathways from among genes, environments, the brain, and behavior.

Impact of Professional Learning on Teachers' Representational Strategies and Students' Cognitive Engagement with Molecular Genetics Concepts

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Nichols, Kim

2018-01-01

A variety of practices and specialised representational systems are required to understand, communicate and construct molecular genetics knowledge. This study describes teachers' use of multimodal representations of molecular genetics concepts and how their strategies and choice of resources were interpreted, understood and used by students to…

Effects of Freshwater Pollution on the Genetics of Zebra Mussels (Dreissena polymorpha at the Molecular and Population Level

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Emilia G. Thomas

2014-01-01

Full Text Available Revealing long-term effects of contaminants on the genetic structure of organisms inhabiting polluted environments should encompass analyses at the population, molecular, and cellular level. Following this concept, we studied the genetic constitution of zebra mussel populations from a polluted (Dp and reference sites (Cl at the river Drava, Croatia, and applied microsatellite and DNA damage analyses (Comet assay, micronucleus test (MNT. Additionally, mussels from both populations were exposed to polluted wastewater in the laboratory for three days, and DNA damage was analyzed to evaluate acclimatization and genetic adaptation of the investigated populations to the polluted environment. The two populations differed in their genetic constitution. Microsatellite analysis suggested that Dp had undergone a genetic bottleneck. Comet assay did not indicate any difference in DNA damage between the two populations, but MNT revealed that Dp had an increased percentage of micronuclei in hemocytes in comparison to Cl. The laboratory experiment revealed that Dp had a lower percentage of tail DNA and a higher percentage of micronuclei than Cl. These differences between populations were possibly caused by an overall decreased fitness of Dp due to genetic drift and by an enhanced DNA repair mechanism due to acclimatization to pollution in the source habitat.

Effects of freshwater pollution on the genetics of zebra mussels (Dreissena polymorpha) at the molecular and population level.

Science.gov (United States)

Thomas, Emilia G; Srut, Maja; Stambuk, Anamaria; Klobučar, Göran I V; Seitz, Alfred; Griebeler, Eva Maria

2014-01-01

Revealing long-term effects of contaminants on the genetic structure of organisms inhabiting polluted environments should encompass analyses at the population, molecular, and cellular level. Following this concept, we studied the genetic constitution of zebra mussel populations from a polluted (Dp) and reference sites (Cl) at the river Drava, Croatia, and applied microsatellite and DNA damage analyses (Comet assay, micronucleus test (MNT)). Additionally, mussels from both populations were exposed to polluted wastewater in the laboratory for three days, and DNA damage was analyzed to evaluate acclimatization and genetic adaptation of the investigated populations to the polluted environment. The two populations differed in their genetic constitution. Microsatellite analysis suggested that Dp had undergone a genetic bottleneck. Comet assay did not indicate any difference in DNA damage between the two populations, but MNT revealed that Dp had an increased percentage of micronuclei in hemocytes in comparison to Cl. The laboratory experiment revealed that Dp had a lower percentage of tail DNA and a higher percentage of micronuclei than Cl. These differences between populations were possibly caused by an overall decreased fitness of Dp due to genetic drift and by an enhanced DNA repair mechanism due to acclimatization to pollution in the source habitat.

Asymmetry in family history implicates nonstandard genetic mechanisms: application to the genetics of breast cancer.

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Clarice R Weinberg

2014-03-01

Full Text Available Genome-wide association studies typically target inherited autosomal variants, but less studied genetic mechanisms can play a role in complex disease. Sex-linked variants aside, three genetic phenomena can induce differential risk in maternal versus paternal lineages of affected individuals: 1. maternal effects, reflecting the maternal genome's influence on prenatal development; 2. mitochondrial variants, which are inherited maternally; 3. autosomal genes, whose effects depend on parent of origin. We algebraically show that small asymmetries in family histories of affected individuals may reflect much larger genetic risks acting via those mechanisms. We apply these ideas to a study of sisters of women with breast cancer. Among 5,091 distinct families of women reporting that exactly one grandmother had breast cancer, risk was skewed toward maternal grandmothers (p<0.0001, especially if the granddaughter was diagnosed between age 45 and 54. Maternal genetic effects, mitochondrial variants, or variant genes with parent-of-origin effects may influence risk of perimenopausal breast cancer.

Molecular genetics of human primary microcephaly: an overview

Science.gov (United States)

2015-01-01

Autosomal recessive primary microcephaly (MCPH) is a neurodevelopmental disorder that is characterised by microcephaly present at birth and non-progressive mental retardation. Microcephaly is the outcome of a smaller but architecturally normal brain; the cerebral cortex exhibits a significant decrease in size. MCPH is a neurogenic mitotic disorder, though affected patients demonstrate normal neuronal migration, neuronal apoptosis and neural function. Twelve MCPH loci (MCPH1-MCPH12) have been mapped to date from various populations around the world and contain the following genes: Microcephalin, WDR62, CDK5RAP2, CASC5, ASPM, CENPJ, STIL, CEP135, CEP152, ZNF335, PHC1 and CDK6. It is predicted that MCPH gene mutations may lead to the disease phenotype due to a disturbed mitotic spindle orientation, premature chromosomal condensation, signalling response as a result of damaged DNA, microtubule dynamics, transcriptional control or a few other hidden centrosomal mechanisms that can regulate the number of neurons produced by neuronal precursor cells. Additional findings have further elucidated the microcephaly aetiology and pathophysiology, which has informed the clinical management of families suffering from MCPH. The provision of molecular diagnosis and genetic counselling may help to decrease the frequency of this disorder. PMID:25951892

Using Genetic Buffering Relationships Identified in Fission Yeast To Elucidate the Molecular Pathology of Tuberous Sclerosis

Science.gov (United States)

2016-07-01

tsc1 and tsc2 loss of function mutations in Schizosaccharomyces pombe. Northeast Regional Yeast Meeting, June 16-17, University at Buffalo, The State...AWARD NUMBER: W81XWH-14-1-0169 TITLE: Using Genetic Buffering Relationships Identified in Fission Yeast To Elucidate the Molecular Pathology of...SUBTITLE Using Genetic Buffering Relationships Identified in Fission 5a. CONTRACT NUMBER W81XWH-14-1-0169 Yeast to Elucidate the Molecular Pathology

Molecular profiling techniques as tools to detect potential unintended effects in genetically engineered maize

CSIR Research Space (South Africa)

Barros, E

2010-05-01

Full Text Available Molecular Profiling Techniques as Tools to Detect Potential Unintended Effects in Genetically Engineered Maize Eugenia Barros Introduction In the early stages of production and commercialization of foods derived from genetically engineered (GE) plants... systems. In a recent paper published in Plant Biotechnology Journal,4 we compared two transgenic white maize lines with the non-transgenic counterpart to investigate two possible sources of variation: genetic engineering and environmental variation...

Journal of Genetics | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Genetics. Rob J. Kulathinal. Articles written in Journal of Genetics. Volume 87 Issue 4 December 2008 pp 327-338 Perspectives. The molecular basis of speciation: from patterns to processes, rules to mechanisms · Rob J. Kulathinal Rama S. Singh · More Details Abstract Fulltext PDF.

Resveratrol and Calcium Signaling: Molecular Mechanisms and Clinical Relevance

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Audrey E. McCalley

2014-06-01

Full Text Available Resveratrol is a naturally occurring compound contributing to cellular defense mechanisms in plants. Its use as a nutritional component and/or supplement in a number of diseases, disorders, and syndromes such as chronic diseases of the central nervous system, cancer, inflammatory diseases, diabetes, and cardiovascular diseases has prompted great interest in the underlying molecular mechanisms of action. The present review focuses on resveratrol, specifically its isomer trans-resveratrol, and its effects on intracellular calcium signaling mechanisms. As resveratrol’s mechanisms of action are likely pleiotropic, its effects and interactions with key signaling proteins controlling cellular calcium homeostasis are reviewed and discussed. The clinical relevance of resveratrol’s actions on excitable cells, transformed or cancer cells, immune cells and retinal pigment epithelial cells are contrasted with a review of the molecular mechanisms affecting calcium signaling proteins on the plasma membrane, cytoplasm, endoplasmic reticulum, and mitochondria. The present review emphasizes the correlation between molecular mechanisms of action that have recently been identified for resveratrol and their clinical implications.

Reno-endocrinal disorders: A basic understanding of the molecular genetics

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Sukhminder Jit Singh Bajwa

2012-01-01

Full Text Available The successful management of endocrine diseases is greatly helped by the complete understanding of the underlying pathology. The knowledge about the molecular genetics contributes immensely in the appropriate identification of the causative factors of the diseases and their subsequent management. The fields of nephrology and endocrinology are also interrelated to a large extent. Besides performing the secretory functions, the renal tissue also acts as target organ for many hormones such as antidiuretic hormone (ADH, atrial natriuretic peptides (ANP, and aldosterone. Understanding the molecular genetics of these hormones is important because the therapeutic interventions in many of these conditions is related to shared renal and endocrine functions, including the anemia of renal disease, chronic kidney disease, mineral bone disorders, and hypertension related to chronic kidney disease. Their understanding and in-depth knowledge is very essential in designing and formulating the therapeutic plans and innovating new management strategies. However, we still have to go a long way in order to completely understand the various confounding causative relationships between the pathology and disease of these reno-endocrinal manifestations.

Incorporating personalized gene sequence variants, molecular genetics knowledge, and health knowledge into an EHR prototype based on the Continuity of Care Record standard

Science.gov (United States)

Jing, Xia; Kay, Stephen; Marley, Tom; Hardiker, Nicholas R.; Cimino, James J.

2011-01-01

Summary Objectives The current volume and complexity of genetic tests, and the molecular genetics knowledge and health knowledge related to interpretation of the results of those tests, are rapidly outstripping the ability of individual clinicians to recall, understand and convey to their patients information relevant to their care. The tailoring of molecular genetics knowledge and health knowledge in clinical settings is important both for the provision of personalized medicine and to reduce clinician information overload. In this paper we describe the incorporation, customization and demonstration of molecular genetic data (mainly sequence variants), molecular genetics knowledge and health knowledge into a standards-based electronic health record (EHR) prototype developed specifically for this study. Methods We extended the CCR (Continuity of Care Record), an existing EHR standard for representing clinical data, to include molecular genetic data. An EHR prototype was built based on the extended CCR and designed to display relevant molecular genetics knowledge and health knowledge from an existing knowledge base for cystic fibrosis (OntoKBCF). We reconstructed test records from published case reports and represented them in the CCR schema. We then used the EHR to dynamically filter molecular genetics knowledge and health knowledge from OntoKBCF using molecular genetic data and clinical data from the test cases. Results The molecular genetic data were successfully incorporated in the CCR by creating a category of laboratory results called “Molecular Genetics ” and specifying a particular class of test (“Gene Mutation Test”) in this category. Unlike other laboratory tests reported in the CCR, results of tests in this class required additional attributes (“Molecular Structure” and “Molecular Position”) to support interpretation by clinicians. These results, along with clinical data (age, sex, ethnicity, diagnostic procedures, and therapies) were used

Quantum chemical approaches: semiempirical molecular orbital and hybrid quantum mechanical/molecular mechanical techniques.

Science.gov (United States)

Bryce, Richard A; Hillier, Ian H

2014-01-01

The use of computational quantum chemical methods to aid drug discovery is surveyed. An overview of the various computational models spanning ab initio, density function theory, semiempirical molecular orbital (MO), and hybrid quantum mechanical (QM)/molecular mechanical (MM) methods is given and their strengths and weaknesses are highlighted, focussing on the challenge of obtaining the accuracy essential for them to make a meaningful contribution to drug discovery. Particular attention is given to hybrid QM/MM and semiempirical MO methods which have the potential to yield the necessary accurate predictions of macromolecular structure and reactivity. These methods are shown to have advanced the study of many aspects of substrate-ligand interactions relevant to drug discovery. Thus, the successful parametrization of semiempirical MO methods and QM/MM methods can be used to model noncovalent substrate-protein interactions, and to lead to improved scoring functions. QM/MM methods can be used in crystal structure refinement and are particularly valuable for modelling covalent protein-ligand interactions and can thus aid the design of transition state analogues. An extensive collection of examples from the areas of metalloenzyme structure, enzyme inhibition, and ligand binding affinities and scoring functions are used to illustrate the power of these techniques.

Molecular genetics made simple

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Heba Sh. Kassem

2012-07-01

Full Text Available Genetics have undoubtedly become an integral part of biomedical science and clinical practice, with important implications in deciphering disease pathogenesis and progression, identifying diagnostic and prognostic markers, as well as designing better targeted treatments. The exponential growth of our understanding of different genetic concepts is paralleled by a growing list of genetic terminology that can easily intimidate the unfamiliar reader. Rendering genetics incomprehensible to the clinician however, defeats the very essence of genetic research: its utilization for combating disease and improving quality of life. Herein we attempt to correct this notion by presenting the basic genetic concepts along with their usefulness in the cardiology clinic. Bringing genetics closer to the clinician will enable its harmonious incorporation into clinical care, thus not only restoring our perception of its simple and elegant nature, but importantly ensuring the maximal benefit for our patients.

Molecular genetics made simple

Science.gov (United States)

Kassem, Heba Sh.; Girolami, Francesca; Sanoudou, Despina

2012-01-01

Abstract Genetics have undoubtedly become an integral part of biomedical science and clinical practice, with important implications in deciphering disease pathogenesis and progression, identifying diagnostic and prognostic markers, as well as designing better targeted treatments. The exponential growth of our understanding of different genetic concepts is paralleled by a growing list of genetic terminology that can easily intimidate the unfamiliar reader. Rendering genetics incomprehensible to the clinician however, defeats the very essence of genetic research: its utilization for combating disease and improving quality of life. Herein we attempt to correct this notion by presenting the basic genetic concepts along with their usefulness in the cardiology clinic. Bringing genetics closer to the clinician will enable its harmonious incorporation into clinical care, thus not only restoring our perception of its simple and elegant nature, but importantly ensuring the maximal benefit for our patients. PMID:25610837

Progress in the molecular and genetic modification breeding of beef cattle in China.

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Tong, Bin; Zhang, Li; Li, Guang-Peng

2017-11-20

The studies of beef cattle breeding in China have been greatly improved with the rapid development of the international beef cattle industrialization. The beef cattle breeding technologies have rapidly transformed from traditional breeding to molecular marker-assisted breeding, genomic selection and genetic modification breeding. Hundreds of candidate genes and molecular markers associated with growth, meat quality, reproduction performance and diseases resistance have been identified, and some of them have already been used in cattle breeding. Genes and molecular markers associated with growth and development are focused on the growth hormone, muscle regulatory factors, myostatin and insulin-like growth factors. Meat quality is mediated by fatty acid transport and deposition related signals, calpains and calpain system, muscle regulatory factors and muscle growth regulation pathways. Reproduction performance is regulated by GnRH-FSH-LH, growth differentiation factor 9, prolactin receptor and forkhead box protein O1. Disease resistance is modulated by the major histocompatibility complex gene family, toll-like receptors, mannose-binding lectin and interferon gene signals. In this review, we summarize the most recent progress in beef cattle breeding in marker-assisted selection, genome-wide selection and genetic modification breeding, aiming to provide a reference for further genetic breeding research of beef cattle in China.

Mechanistic insights into Mg2+-independent prenylation by CloQ from classical molecular mechanics and hybrid quantum mechanics/molecular mechanics molecular dynamics simulations.

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Bayse, Craig A; Merz, Kenneth M

2014-08-05

Understanding the mechanism of prenyltransferases is important to the design of engineered proteins capable of synthesizing derivatives of naturally occurring therapeutic agents. CloQ is a Mg(2+)-independent aromatic prenyltransferase (APTase) that transfers a dimethylallyl group to 4-hydroxyphenylpyruvate in the biosynthetic pathway for clorobiocin. APTases consist of a common ABBA fold that defines a β-barrel containing the reaction cavity. Positively charged basic residues line the inside of the β-barrel of CloQ to activate the pyrophosphate leaving group to replace the function of the Mg(2+) cofactor in other APTases. Classical molecular dynamics simulations of CloQ, its E281G and F68S mutants, and the related NovQ were used to explore the binding of the 4-hydroxyphenylpyruvate (4HPP) and dimethylallyl diphosphate substrates in the reactive cavity and the role of various conserved residues. Hybrid quantum mechanics/molecular mechanics potential of mean force (PMF) calculations show that the effect of the replacement of the Mg(2+) cofactor with basic residues yields a similar activation barrier for prenylation to Mg(2+)-dependent APTases like NphB. The topology of the binding pocket for 4HPP is important for selective prenylation at the ortho position of the ring. Methylation at this position alters the conformation of the substrate for O-prenylation at the phenol group. Further, a two-dimensional PMF scan shows that a "reverse" prenylation product may be a possible target for protein engineering.

Molecular mechanisms involved in convergent crop domestication.

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Lenser, Teresa; Theißen, Günter

2013-12-01

Domestication has helped to understand evolution. We argue that, vice versa, novel insights into evolutionary principles could provide deeper insights into domestication. Molecular analyses have demonstrated that convergent phenotypic evolution is often based on molecular changes in orthologous genes or pathways. Recent studies have revealed that during plant domestication the causal mutations for convergent changes in key traits are likely to be located in particular genes. These insights may contribute to defining candidate genes for genetic improvement during the domestication of new plant species. Such efforts may help to increase the range of arable crops available, thus increasing crop biodiversity and food security to help meet the predicted demands of the continually growing global population under rapidly changing environmental conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Genetic and molecular characterization of photoperiod and thermo-sensitive male sterility in rice.

Science.gov (United States)

Fan, Yourong; Zhang, Qifa

2018-03-01

A review on photoperiod and temperature-sensitive genic male sterility in rice. Male sterility in plants, facilitating the development of hybrid crops, has made great contribution to crop productivity worldwide. Environment-sensitive genic male sterility (EGMS), including photoperiod-sensitive genic male sterility (PGMS) and temperature-sensitive genic male sterility (TGMS), has provided a special class of germplasms for the breeding of "two-line" hybrids in several crops. In rice, the finding of the PGMS NK58S mutant in 1973 started the journey of research and breeding of two-line hybrids. Genetic and molecular characterization of these germplasms demonstrated diverse genes and molecular mechanisms of male sterility regulation. Two loci identified from NK58S, PMS1 and PMS3, both encode long noncoding RNAs. A major TGMS locus, TMS5, found in the TGMS line Annong S-1, encodes an RNase Z. A reverse PGMS mutant carbon starved anther encodes an R2R3 MYB transcription factor. Breeding efforts in the last three decades have resulted in hundreds of EGMS lines and two-line hybrids released to rice production, which have greatly elevated the yield potential and grain quality of rice varieties. The enhanced molecular understanding will offer new strategies for the development of EGMS lines thus further improving two-line hybrid breeding of rice as well as other crops.

Molecular insights into the proliferation and progression mechanisms of the oral cancer: Strategies for the effective and personalized therapy

Directory of Open Access Journals (Sweden)

Masakatsu Fukuda

2012-02-01

Full Text Available Oral carcinogenesis is a multifactorial process involving numerous genetic events that alter normal functions of oncogenes and tumor suppressor genes. It is well established that an accumulation of genetic alterations is the basis for the progression from a normal cell to a cancer cell, referred to as multi-step carcinogenesis. This event may be increased the production of growth factors or the number of receptors on the cell surface, and/or increased transcription factors or intracellular signal messengers, further that associated with deregulated control of cell proliferation and apoptosis. Together with the loss of tumor suppressor activity, these changes lead to a cell phenotype that can increase cell proliferation, with loss of cell cohesion, and infiltration to adjacent tissue thus causing distant metastasis. Molecular medicine is responsible for defining the molecular mechanisms that underlie the onset of oral cancer. This review focuses on recent advances in our understanding of the molecular control of the innumerable pathways related to these processes. These may lead to short- or medium term improvements in the diagnosis and prognosis of oral cancerous lesions and to the development of novel therapeutic approaches to this disease.

Genetic diversity and molecular characterization of Saccharomyces cerevisiae strains from winemaking environments

OpenAIRE

Schuller, Dorit Elisabeth

2004-01-01

Tese de doutoramento em Ciências The principal aim of the present work is to assess the genetic diversity of fermenting Saccharomyces cerevisiae strains found in vineyards belonging to the Vinho Verde Region in order to create a strain collection representing the region’s biodiversity wealth as a basis for future strain selection and improvement programs. Validation of molecular techniques for accurate genotyping is an indispensable prerequisite for biogeographical surveys. Molecular ty...

Cystic fibrosis genetics: from molecular understanding to clinical application

Science.gov (United States)

Cutting, Garry R.

2015-01-01

The availability of the human genome sequence and tools for interrogating individual genomes provide an unprecedented opportunity to apply genetics to medicine. Mendelian conditions, which are caused by dysfunction of a single gene, offer powerful examples that illustrate how genetics can provide insights into disease. Cystic fibrosis, one of the more common lethalautosomal recessive Mendelian disorders, is presented here as an example. Recent progress in elucidating disease mechanism and causes of phenotypic variation, as well as in the development of treatments, demonstrates that genetics continues to play an important part in cystic fibrosis research 25 years after the d iscove1y of the disease-causing gene. PMID:25404111

Mechanism of the Glycosidic Bond Cleavage of Mismatched Thymine in Human Thymine DNA Glycosylase Revealed by Classical Molecular Dynamics and Quantum Mechanical/Molecular Mechanical Calculations.

Science.gov (United States)

Kanaan, Natalia; Crehuet, Ramon; Imhof, Petra

2015-09-24

Base excision of mismatched or damaged nucleotides catalyzed by glycosylase enzymes is the first step of the base excision repair system, a machinery preserving the integrity of DNA. Thymine DNA glycosylase recognizes and removes mismatched thymine by cleaving the C1'-N1 bond between the base and the sugar ring. Our quantum mechanical/molecular mechanical calculations of this reaction in human thymine DNA glycosylase reveal a requirement for a positive charge in the active site to facilitate C1'-N1 bond scission: protonation of His151 significantly lowers the free energy barrier for C1'-N1 bond dissociation compared to the situation with neutral His151. Shuttling a proton from His151 to the thymine base further reduces the activation free energy for glycosidic bond cleavage. Classical molecular dynamics simulations of the H151A mutant suggest that the mutation to the smaller, neutral, residue increases the water accessibility of the thymine base, rendering direct proton transfer from the bulk feasible. Quantum mechanical/molecular mechanical calculations of the glycosidic bond cleavage reaction in the H151A mutant show that the activation free energy is slightly lower than in the wild-type enzyme, explaining the experimentally observed higher reaction rates in this mutant.

Molecular mechanisms of thyroid tumorigenesis

International Nuclear Information System (INIS)

Krause, K.; Fuehrer, D.

2008-01-01

Thyroid nodules are the most frequent endocrine disorder and occur in approximately 30% of the German population. Thyroid nodular disease constitutes a very heterogeneous entity. A striking diversity of possible functional and morphological features of a thyroid tumour derived from the same thyroid ancestor cell, is a hallmark of thyroid tumorigenesis and is due to specific genetic alterations. Defects in known candidate genes can be found in up to 70% of differentiated thyroid carcinomas and determine the respective cancer phenotype. Papillary thyroid cancers (PTC) harbour BRAF (or much less frequently RAS) mutations in sporadically occurring tumours, while radiation-induced PTC display chromosomal rearrangements such as RET, TRK, APR9 / BRAF. These genetic events results in constitutive MAPKinase activation. Follicular thyroid cancers (FTC) harbour RAS mutations or PAX8/ PPARγ rearrangements, both of which, however have also been identified in follicular adenoma. In addition, recent studies show, that activation of PI3K/AKT signalling occurs with high frequency in follicular thyroid tumours. Undifferentiated (anaplastic) thyroid cancers (ATC) display genetic features of FTC or PTC, in addition to aberant activation of multiple tyrosinkinase pathways (overexpression or mutations in PI3K and MAPK pathways). This underscores the concept of a sequential evolution of ATC from differentiated thyroid cancer, a process widely conceived to be triggered by p53 inactivation. In contrast, the molecular pathogenesis of benign thyroid tumours, in particular cold thyroid nodules is less known, except for toxic thyroid nodules, which arise from constitutive activation of cAMP signalling, predominantly through TSHR mutations. (orig.)

Genetics of gallstone disease.

Directory of Open Access Journals (Sweden)

Mittal B

2002-04-01

Full Text Available Gallstone disease is a complex disorder where both environmental and genetic factors contribute towards susceptibility to the disease. Epidemiological and family studies suggest a strong genetic component in the causation of this disease. Several genetically derived phenotypes in the population are responsible for variations in lipoprotein types, which in turn affect the amount of cholesterol available in the gall bladder. The genetic polymorphisms in various genes for apo E, apo B, apo A1, LDL receptor, cholesteryl ester transfer and LDL receptor-associated protein have been implicated in gallstone formation. However, presently available information on genetic differences is not able to account for a large number of gallstone patients. The molecular studies in the animal models have not only confirmed the present paradigm of gallstone formation but also helped in identification of novel genes in humans, which might play an important role in pathogenesis of the disease. Precise understanding of such genes and their molecular mechanisms may provide the basis of new targets for rational drug designs and dietary interventions.

The Genetic and Molecular Bases for Hypertrophic Cardiomyopathy: The Role for Calcium Sensitization.

Science.gov (United States)

Ren, Xianfeng; Hensley, Nadia; Brady, Mary Beth; Gao, Wei Dong

2018-02-01

Hypertrophic cardiomyopathy (HCM) affects millions of people around the world as one of the most common genetic heart disorders and leads to cardiac ischemia, heart failure, dysfunction of other organ systems, and increased risk for sudden unexpected cardiac deaths. HCM can be caused by single-point mutations, insertion or deletion mutations, or truncation of cardiac myofilament proteins. The molecular mechanism that leads to disease progression and presentation is still poorly understood, despite decades of investigations. However, recent research has made dramatic advances in the understanding of HCM disease development. Studies have shown that increased calcium sensitivity is a universal feature in HCM. At the molecular level, increased crossbridge force (or power) generation resulting in hypercontractility is the prominent feature. Thus, calcium sensitization/hypercontractility is emerging as the primary stimulus for HCM disease development and phenotypic expression. Cross-bridge inhibition has been shown to halt HCM presentation, and myofilament desensitization appears to reduce lethal arrhythmias in animal models of HCM. These advances in basic research will continue to deepen the knowledge of HCM pathogenesis and are beginning to revolutionize the management of HCM. Copyright © 2018 Elsevier Inc. All rights reserved.

Genetic and clinical characteristics of primary and secondary glioblastoma is associated with differential molecular subtype distribution

OpenAIRE

Li, Rui; Li, Hailin; Yan, Wei; Yang, Pei; Bao, Zhaoshi; Zhang, Chuanbao; Jiang, Tao; You, Yongping

2015-01-01

Glioblastoma multiforme (GBM) is classified into primary (pGBM) or secondary (sGBM) based on clinical progression. However, there are some limits to this classification for insight into genetically and clinically distinction between pGBM and sGBM. The aim of this study is to characterize pGBM and sGBM associating with differential molecular subtype distribution. Whole transcriptome sequencing data was used to assess the distribution of molecular subtypes and genetic alterations in 88 pGBM and...

General perspectives for molecular nuclear imaging

International Nuclear Information System (INIS)

Chung, June Key

2004-01-01

Molecular imaging provides a visualization of normal as well as abnormal cellular processes at a molecular or genetic level rather than at an anatomical level. Conventional medical imaging methods utilize the imaging signals produced by nonspecific physico-chemical interaction. However, molecular imaging methods utilize the imaging signals derived from specific cellular or molecular events. Because molecular and genetic changes precede anatomical change in the course of disease development, molecular imaging can detect early events in disease progression. In the near future, through molecular imaging we can understand basic mechanisms of disease, and diagnose earlier and, subsequently, treat earlier intractable disease such as cancer, neuro-degenerative diseases, and immunologic disorders. In beginning period, nuclear medicine started as a molecular imaging, and has had a leading role in the field of molecular imaging. But recently molecular imaging has been rapidly developed. Besides nuclear imaging, molecular imaging methods such as optical imaging, magnetic resonance imaging are emerging. Each imaging modalities have their advantages and weaknesses. The opportunities from molecular imaging look bright. We should try nuclear medicine continues to have a leading role in molecular imaging

A Report on Molecular Diagnostic Testing for Inherited Retinal Dystrophies by Targeted Genetic Analyses.

Science.gov (United States)

Ramkumar, Hema L; Gudiseva, Harini V; Kishaba, Kameron T; Suk, John J; Verma, Rohan; Tadimeti, Keerti; Thorson, John A; Ayyagari, Radha

2017-02-01

To test the utility of targeted sequencing as a method of clinical molecular testing in patients diagnosed with inherited retinal degeneration (IRD). After genetic counseling, peripheral blood was drawn from 188 probands and 36 carriers of IRD. Single gene testing was performed on each patient in a Clinical Laboratory Improvement Amendment (CLIA) certified laboratory. DNA was isolated, and all exons in the gene of interest were analyzed along with 20 base pairs of flanking intronic sequence. Genetic testing was most often performed on ABCA4, CTRP5, ELOV4, BEST1, CRB1, and PRPH2. Pathogenicity of novel sequence changes was predicted by PolyPhen2 and sorting intolerant from tolerant (SIFT). Of the 225 genetic tests performed, 150 were for recessive IRD, and 75 were for dominant IRD. A positive molecular diagnosis was made in 70 (59%) of probands with recessive IRD and 19 (26%) probands with dominant IRD. Analysis confirmed 12 (34%) of individuals as carriers of familial mutations associated with IRD. Thirty-two novel variants were identified; among these, 17 sequence changes in four genes were predicted to be possibly or probably damaging including: ABCA4 (14), BEST1 (2), PRPH2 (1), and TIMP3 (1). Targeted analysis of clinically suspected genes in 225 subjects resulted in a positive molecular diagnosis in 26% of patients with dominant IRD and 59% of patients with recessive IRD. Novel damaging mutations were identified in four genes. Single gene screening is not an ideal method for diagnostic testing given the phenotypic and genetic heterogeneity among IRD cases. High-throughput sequencing of all genes associated with retinal degeneration may be more efficient for molecular diagnosis.

the genetic and molecular basis of bacterial invasion of epithelial cells

African Journals Online (AJOL)

DR. AMINU

The pathogenic species of bacteria are of great medical importance as causative agents of infectious diseases. Moreover, as the condition of human existence have changed, so have the bacterial species that produce diseases. It is against this background that molecular genetics have now entered the field of microbial ...

Permanent genetic resources added to molecular ecology resources database 1 February 2013-31 March 2013

Czech Academy of Sciences Publication Activity Database

Arias, M. C.; Atteke, C.; Augusto, S. C.; Bailey, J.; Bazaga, P.; Beheregaray, L. B.; Benoit, L.; Blatrix, R.; Born, C.; Brito, R. M.; Chen, H.-K.; Covarrubias, S.; de Vega, C.; Djiéto-Lordon, C.; Dubois, M.-P.; Francisco, F. O.; García, C.; Concalves, P. H. P.; González, C.; Gutiérrez-Rodríguez, C.; Hammer, M. P.; Herrera, C. M.; Itoh, H.; Kamimura, S.; Karaoglu, H.; Kojima, S.; Li, S.-L.; Ling, H. J.; Matos Maravi, Pavel F.; McKey, D.; Mezui-M’Eko, J.; Ornelas, J. F.; Park, R. F.; Pozo, M. I.; Ramula, S.; Rigueiro, C.; Sandoval-Castillo, J.; Santiago, L. R.; Seino, M. M.; Song, C.-B.; Takeshima, H.; Vasemägi, A.; Wellings, C. R.; Yan, J.; Du, Y.-Z.; Zhang, C.-R.; Zhang, T.-Y.

2013-01-01

Roč. 13, č. 4 (2013), s. 760-762 ISSN 1755-098X Institutional support: RVO:60077344 Keywords : molecular ecology Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.626, year: 2013 http://onlinelibrary.wiley.com/doi/10.1111/1755-0998.12121/pdf

Molecular evaluation of genetic variability of wheat elite breeding material

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Brbaklić Ljiljana

2009-01-01

Full Text Available Estimation of genetic variability of breeding material is essential for yield improvement in wheat cultivars. Modern techniques based on molecular markers application are more efficient and precise in genetic variability evaluation then conventional methods. Variability of 96 wheat cultivars and lines was analyzed using four microsatellite markers (Gwm11, Gwm428, Psp3200, Psp3071. The markers were chosen according to their potential association with important agronomical traits indicated in the literature. Total of 31 alleles were detected with maximum number of alleles (11 in Xgwm11 locus. The highest polymorphism information content (PIC value (0,831 was found in the locus Xpsp3071. The genotypes were grouped into three subpopulations based on their similarity in the analyzed loci. The results have indicated wide genetic variability of the studied material and possibility of its application in further breeding process after validation of marker-trait association. .

GENETICS AND MOLECULAR BIOLOGY AND PIG MEAT QUALITY IMPROVEMENT

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J. BULLA

2007-05-01

Full Text Available The main goals in pig breeding have for many years been to improve growth rate, feedconversion and carcass composition. There have been less efforts to improve meat qualityparameters (WHC, pH, tenderness, colour etc. but the main contribution has been areduction of stress susceptibility and PSE meat. Unfortunately, the quantitative geneticapproach has yielded few clues regarding the fundamental genetic changes that accompaniedthe selection of animal for superior carcass attributes. While mapping efforts are makingsignificant major effects on carcass and his quality composition DNA test would be availableto detect some positive or negative alleles. There are clear breed effects on meat quality,which in some cases are fully related to the presence of a single gene with major effect (RYR1,MYF4, H-FABP, LEPR, IGF2. Molecular biology methods provides excellent opportunitiesto improve meat quality in selection schemes within breeds and lines. Selection on majorgenes will not only increase average levels of quality but also decrease variability (ei increaseuniformity. The aim of this paper is to discuss there genetic and non-genetic opportunities.

GENETICS AND MOLECULAR BIOLOGY AND PIG MEAT QUALITY IMPROVEMENT

Directory of Open Access Journals (Sweden)

BULLA, J.

2007-01-01

Full Text Available The main goals in pig breeding have for many years been to improve growth rate, feedconversion and carcass composition. There have been less efforts to improve meat qualityparameters (WHC, pH, tenderness, colour etc. but the main contribution has been areduction of stress susceptibility and PSE meat. Unfortunately, the quantitative geneticapproach has yielded few clues regarding the fundamental genetic changes that accompaniedthe selection of animal for superior carcass attributes. While mapping efforts are makingsignificant major effects on carcass and his quality composition DNA test would be availableto detect some positive or negative alleles. There are clear breed effects on meat quality,which in some cases are fully related to the presence of a single gene with major effect (RYR1,MYF4, H-FABP, LEPR, IGF2. Molecular biology methods provides excellent opportunitiesto improve meat quality in selection schemes within breeds and lines. Selection on majorgenes will not only increase average levels of quality but also decrease variability (ei increaseuniformity. The aim of this paper is to discuss there genetic and non-genetic opportunities.

Multiscale Quantum Mechanics/Molecular Mechanics Simulations with Neural Networks.

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Shen, Lin; Wu, Jingheng; Yang, Weitao

2016-10-11

Molecular dynamics simulation with multiscale quantum mechanics/molecular mechanics (QM/MM) methods is a very powerful tool for understanding the mechanism of chemical and biological processes in solution or enzymes. However, its computational cost can be too high for many biochemical systems because of the large number of ab initio QM calculations. Semiempirical QM/MM simulations have much higher efficiency. Its accuracy can be improved with a correction to reach the ab initio QM/MM level. The computational cost on the ab initio calculation for the correction determines the efficiency. In this paper we developed a neural network method for QM/MM calculation as an extension of the neural-network representation reported by Behler and Parrinello. With this approach, the potential energy of any configuration along the reaction path for a given QM/MM system can be predicted at the ab initio QM/MM level based on the semiempirical QM/MM simulations. We further applied this method to three reactions in water to calculate the free energy changes. The free-energy profile obtained from the semiempirical QM/MM simulation is corrected to the ab initio QM/MM level with the potential energies predicted with the constructed neural network. The results are in excellent accordance with the reference data that are obtained from the ab initio QM/MM molecular dynamics simulation or corrected with direct ab initio QM/MM potential energies. Compared with the correction using direct ab initio QM/MM potential energies, our method shows a speed-up of 1 or 2 orders of magnitude. It demonstrates that the neural network method combined with the semiempirical QM/MM calculation can be an efficient and reliable strategy for chemical reaction simulations.

Physiological and molecular biochemical mechanisms of bile formation

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Reshetnyak, Vasiliy Ivanovich

2013-01-01

This review considers the physiological and molecular biochemical mechanisms of bile formation. The composition of bile and structure of a bile canaliculus, biosynthesis and conjugation of bile acids, bile phospholipids, formation of bile micellar structures, and enterohepatic circulation of bile acids are described. In general, the review focuses on the molecular physiology of the transporting systems of the hepatocyte sinusoidal and apical membranes. Knowledge of physiological and biochemical basis of bile formation has implications for understanding the mechanisms of development of pathological processes, associated with diseases of the liver and biliary tract. PMID:24259965

Internal force corrections with machine learning for quantum mechanics/molecular mechanics simulations.

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Wu, Jingheng; Shen, Lin; Yang, Weitao

2017-10-28

Ab initio quantum mechanics/molecular mechanics (QM/MM) molecular dynamics simulation is a useful tool to calculate thermodynamic properties such as potential of mean force for chemical reactions but intensely time consuming. In this paper, we developed a new method using the internal force correction for low-level semiempirical QM/MM molecular dynamics samplings with a predefined reaction coordinate. As a correction term, the internal force was predicted with a machine learning scheme, which provides a sophisticated force field, and added to the atomic forces on the reaction coordinate related atoms at each integration step. We applied this method to two reactions in aqueous solution and reproduced potentials of mean force at the ab initio QM/MM level. The saving in computational cost is about 2 orders of magnitude. The present work reveals great potentials for machine learning in QM/MM simulations to study complex chemical processes.

Cellular and molecular mechanisms of metformin: an overview

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Viollet, Benoit; Guigas, Bruno; Sanz Garcia, Nieves; Leclerc, Jocelyne; Foretz, Marc; Andreelli, Fabrizio

2012-01-01

Considerable efforts have been made since the 1950s to better understand the cellular and molecular mechanisms of action of metformin, a potent antihyperglycemic agent now recommended as the first line oral therapy for type 2 diabetes (T2D). The main effect of this drug from the biguanide family is to acutely decrease hepatic glucose production, mostly through a mild and transient inhibition of the mitochondrial respiratory-chain complex 1. In addition, the resulting decrease in hepatic energy status activates the AMP-activated protein kinase (AMPK), a cellular metabolic sensor, providing a generally accepted mechanism for metformin action on hepatic gluconeogenic program. The demonstration that the respiratory-chain complex 1, but not AMPK, is the primary target of metformin was recently strengthened by showing that the metabolic effect of the drug is preserved in liver-specific AMPK-deficient mice. Beyond its effect on glucose metabolism, metformin was reported to restore ovarian function in polycystic ovary syndrome, reduce fatty liver and to lower microvascular and macrovascular complications associated with T2D. Its use was also recently suggested as an adjuvant treatment for cancer or gestational diabetes, and for the prevention in pre-diabetic populations. These emerging new therapeutic areas for metformin will be reviewed together with recent data from pharmacogenetic studies linking genetic variations to drug response, a promising new step towards personalized medicine in the treatment of T2D. PMID:22117616

STATINS AND MYOPATHY: MOLECULAR MECHANISMS

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O. M. Drapkina

2012-01-01

Full Text Available The safety of statin therapy is considered. In particular the reasons of a complication such as myopathy are discussed in detail. The molecular mechanisms of statin myopathy , as well as its risk factors are presented. The role of coenzyme Q10 in the myopathy development and coenzyme Q10 application for the prevention of this complication are considered. 

Excessive Cap-dependent Translation as a Molecular Mechanism Underlying ASD

Science.gov (United States)

2014-10-01

Frankfurt, Germany 6) Adler Lecture, 30th Annual Retreat, Mahoney Institute for Neurosciences, University of Pennsylvania, Philadelphia... Deregulation of EIF4E: a novel mechanism for autism. J. Med. Genet. 46, 759–765 (2009). 7. Ruggero, D. et al. The translation factor eIF-4E promotes...Hughes, S. B. Shen, D. S. Clair, Z. Miedzybrodzka, Deregulation of EIF4E: A novel mechanism for autism. J. Med. Genet. 46, 759–765 (2009). 48. E. Klann

A pseudobond parametrization for improved electrostatics in quantum mechanical/molecular mechanical simulations of enzymes.

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Parks, Jerry M; Hu, Hao; Cohen, Aron J; Yang, Weitao

2008-10-21

The pseudobond method is used in quantum mechanical/molecular mechanical (QM/MM) simulations in which a covalent bond connects the quantum mechanical and classical subsystems. In this method, the molecular mechanical boundary atom is replaced by a special quantum mechanical atom with one free valence that forms a bond with the rest of the quantum mechanical subsystem. This boundary atom is modified through the use of a parametrized effective core potential and basis set. The pseudobond is designed to reproduce the properties of the covalent bond that it has replaced, while invoking as small a perturbation as possible on the system. Following the work of Zhang [J. Chem. Phys. 122, 024114 (2005)], we have developed new pseudobond parameters for use in the simulation of enzymatic systems. Our parameters yield improved electrostatics and deprotonation energies, while at the same time maintaining accurate geometries. We provide parameters for C(ps)(sp(3))-C(sp(3)), C(ps)(sp(3))-C(sp(2),carbonyl), and C(ps)(sp(3))-N(sp(3)) pseudobonds, which allow the interface between the quantum mechanical and molecular mechanical subsystems to be constructed at either the C(alpha)-C(beta) bond of a given amino acid residue or along the peptide backbone. In addition, we demonstrate the efficiency of our parametrization method by generating residue-specific pseudobond parameters for a single amino acid. Such an approach may enable higher accuracy than general purpose parameters for specific QM/MM applications.

Perspectives of genetic engineering in radiobiology

International Nuclear Information System (INIS)

Khanson, K.P.; Zvonareva, N.B.; Evtushenko, V.I.

1988-01-01

Present evidence on the use of genetic engineering methods in studying the molecular mechanism of radiation damage and repair of DNA, as well as radiation mutagenesis and carcinogenesis has been summarized. The new approach to radiobiological research has proved to be extremely fruitful. Some previously unknown types of structural disorders in DNA molecule have been discovered, some repair genes isolated and their primary structure established, some aspects of radiation mutagenesis elucidated, and research into disiphering the molecular bases of neoplastic transformations of exposed cells are being successfully investigated. The perspectives of using genetic engineering methods in radiobiology are discussed

Molecular dynamics and Monte Carlo calculations in statistical mechanics

International Nuclear Information System (INIS)

Wood, W.W.; Erpenbeck, J.J.

1976-01-01

Monte Carlo and molecular dynamics calculations on statistical mechanical systems is reviewed giving some of the more significant recent developments. It is noted that the term molecular dynamics refers to the time-averaging technique for hard-core and square-well interactions and for continuous force-law interactions. Ergodic questions, methodology, quantum mechanical, Lorentz, and one-dimensional, hard-core, and square and triangular-well systems, short-range soft potentials, and other systems are included. 268 references

Molecular and Chemical Genetic Approaches to Developmental Origins of Aging and Disease in Zebrafish

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Sasaki, Tomoyuki; Kishi, Shuji

2013-01-01

The incidence of diseases increases rapidly with age, accompanied by progressive deteriorations of physiological functions in organisms. Aging-associated diseases are sporadic but mostly inevitable complications arising from senescence. Senescence is often considered the antithesis of early development, but yet there may be factors and mechanisms in common between these two phenomena over the dynamic process of aging. The association between early development and late-onset disease with advancing age is thought to come from a consequence of developmental plasticity, the phenomenon by which one genotype can give rise to a range of physiologically and/or morphologically adaptive states in response to different environmental or genetic perturbations. On the one hand, we hypothesized that the future aging process can be predictive based on adaptivity during the early developmental period. Modulating the thresholds of adaptive plasticity by chemical genetic approaches, we have been investigating whether any relationship exists between the regulatory mechanisms that function in early development and in senescence using the zebrafish (Danio rerio), a small freshwater fish and a useful model animal for genetic studies. We have successfully conducted experiments to isolate zebrafish mutants expressing apparently altered senescence phenotypes during embryogenesis (“embryonic senescence”), subsequently showing shortened lifespan in adulthoods. We anticipate that previously uncharacterized developmental genes may mediate the aging process and play a pivotal role in senescence. On the other hand, unexpected senescence-related genes might also be involved in the early developmental process and regulation. The ease of manipulation using the zebrafish system allows us to conduct an exhaustive exploration of novel genes and small molecular compounds that can be linked to the senescence phenotype, and thereby facilitates searching for the evolutionary and developmental origins

Molecular characterization and genetic diversity of different genotypes of Oryza sativa and Oryza glaberrima

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Caijin Chen

2017-11-01

Conclusions: Genetic diversity studies revealed that 50 rice types were clustered into different subpopulations whereas three genotypes were admixtures. Molecular fingerprinting and 10 specific markers were obtained to identify the 53 rice genotypes. These results can facilitate the potential utilization of sibling species in rice breeding and molecular classification of O. sativa and O. glaberrima germplasms.

The progress of molecular biology in radiation research

International Nuclear Information System (INIS)

Wei Kang

1989-01-01

The recent progress in application of molecular biology techniques in the study of radiation biology is reviewed. The three sections are as follows: (1) the study of DNA damage on molecular level, (2) the molecular mechanism of radiation cell genetics, including chromosome abberation and cell mutation, (3) the study on DNA repair gene with DNA mediated gene transfer techniques

Genetic Contributions to Clinical Pain and Analgesia: Avoiding Pitfalls in Genetic Research

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Kim, Hyungsuk; Clark, David; Dionne, Raymond A.

2010-01-01

Understanding the genetic basis of human variations in pain is critical to elucidating the molecular basis of pain sensitivity, variable responses to analgesic drugs, and, ultimately, to individualized treatment of pain and improved public health. With the help of recently accumulated knowledge and advanced technologies, pain researchers hope to gain insight into genetic mechanisms of pain and eventually apply this knowledge to pain treatment. Perspective We critically reviewed the published literature to examine the strength of evidence supporting genetic influences on clinical and human experimental pain. Based on this evidence and the experience of false associations that have occurred in other related disciplines, we provide recommendations for avoiding pitfalls in pain genetic research. PMID:19559388

Molecular genetics of follicular cell thyroid carcinoma

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Valentina D. Yakushina

2016-09-01

Full Text Available Thyroid cancer is the most frequent endocrine malignancy. In the most cases thyroid cancer arises from follicular cells. Diagnosis of the cancer is based on the cytological analysis of fine needle aspiration biopsy of thyroid nodes. But the accuracy of the cytological diagnosis is about 80% that leads to the false positive and false negative cases and wrong strategy of treatment. Identification of genetic and epigenetic markers in the biopsies will allow to improve diagnostic accuracy. This article describes mutations, aberrant DNA methylation and abnormal microRNA expression constituting the core of molecular genetics of follicular cell thyroid cancer. The mutations given in the article includes point mutations, fusions and copy number variation. Besides frequent and well described driver mutations in genes of МАРK, PI3K/Akt and Wnt signaling pathways, as well as TP53 and TERT genes, we introduce here less frequent mutations appeared in the literature during the past two years. In addition the article contains examples of diagnostic panels applying these markers.

Molecular mechanisms of fluoride toxicity.

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Barbier, Olivier; Arreola-Mendoza, Laura; Del Razo, Luz María

2010-11-05

Halfway through the twentieth century, fluoride piqued the interest of toxicologists due to its deleterious effects at high concentrations in human populations suffering from fluorosis and in in vivo experimental models. Until the 1990s, the toxicity of fluoride was largely ignored due to its "good reputation" for preventing caries via topical application and in dental toothpastes. However, in the last decade, interest in its undesirable effects has resurfaced due to the awareness that this element interacts with cellular systems even at low doses. In recent years, several investigations demonstrated that fluoride can induce oxidative stress and modulate intracellular redox homeostasis, lipid peroxidation and protein carbonyl content, as well as alter gene expression and cause apoptosis. Genes modulated by fluoride include those related to the stress response, metabolic enzymes, the cell cycle, cell-cell communications and signal transduction. The primary purpose of this review is to examine recent findings from our group and others that focus on the molecular mechanisms of the action of inorganic fluoride in several cellular processes with respect to potential physiological and toxicological implications. This review presents an overview of the current research on the molecular aspects of fluoride exposure with emphasis on biological targets and their possible mechanisms of involvement in fluoride cytotoxicity. The goal of this review is to enhance understanding of the mechanisms by which fluoride affects cells, with an emphasis on tissue-specific events in humans. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Human fertility, molecular genetics, and natural selection in modern societies.

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Felix C Tropf

Full Text Available Research on genetic influences on human fertility outcomes such as number of children ever born (NEB or the age at first childbirth (AFB has been solely based on twin and family-designs that suffer from problematic assumptions and practical limitations. The current study exploits recent advances in the field of molecular genetics by applying the genomic-relationship-matrix based restricted maximum likelihood (GREML methods to quantify for the first time the extent to which common genetic variants influence the NEB and the AFB of women. Using data from the UK and the Netherlands (N = 6,758, results show significant additive genetic effects on both traits explaining 10% (SE = 5 of the variance in the NEB and 15% (SE = 4 in the AFB. We further find a significant negative genetic correlation between AFB and NEB in the pooled sample of -0.62 (SE = 0.27, p-value = 0.02. This finding implies that individuals with genetic predispositions for an earlier AFB had a reproductive advantage and that natural selection operated not only in historical, but also in contemporary populations. The observed postponement in the AFB across the past century in Europe contrasts with these findings, suggesting an evolutionary override by environmental effects and underscoring that evolutionary predictions in modern human societies are not straight forward. It emphasizes the necessity for an integrative research design from the fields of genetics and social sciences in order to understand and predict fertility outcomes. Finally, our results suggest that we may be able to find genetic variants associated with human fertility when conducting GWAS-meta analyses with sufficient sample size.

Genetic Forms of Epilepsies and other Paroxysmal Disorders

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Olson, Heather E.; Poduri, Annapurna; Pearl, Phillip L.

2016-01-01

Genetic mechanisms explain the pathophysiology of many forms of epilepsy and other paroxysmal disorders such as alternating hemiplegia of childhood, familial hemiplegic migraine, and paroxysmal dyskinesias. Epilepsy is a key feature of well-defined genetic syndromes including Tuberous Sclerosis Complex, Rett syndrome, Angelman syndrome, and others. There is an increasing number of singe gene causes or susceptibility factors associated with several epilepsy syndromes, including the early onset epileptic encephalopathies, benign neonatal/infantile seizures, progressive myoclonus epilepsies, genetic generalized and benign focal epilepsies, epileptic aphasias, and familial focal epilepsies. Molecular mechanisms are diverse, and a single gene can be associated with a broad range of phenotypes. Additional features, such as dysmorphisms, head size, movement disorders, and family history may provide clues to a genetic diagnosis. Genetic testing can impact medical care and counseling. We discuss genetic mechanisms of epilepsy and other paroxysmal disorders, tools and indications for genetic testing, known genotype-phenotype associations, the importance of genetic counseling, and a look towards the future of epilepsy genetics. PMID:25192505

Genetic diversity assessment of sesame core collection in China by phenotype and molecular markers and extraction of a mini-core collection

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Zhang Yanxin

2012-11-01

Full Text Available Abstract Background Sesame (Sesamum indicum L. is one of the four major oil crops in China. A sesame core collection (CC was established in China in 2000, but no complete study on its genetic diversity has been carried out at either the phenotypic or molecular level. To provide technical guidance, a theoretical basis for further collection, effective protection, reasonable application, and a complete analysis of sesame genetic resources, a genetic diversity assessment of the sesame CC in China was conducted using phenotypic and molecular data and by extracting a sesame mini-core collection (MC. Results Results from a genetic diversity assessment of sesame CC in China were significantly inconsistent at the phenotypic and molecular levels. A Mantel test revealed the insignificant correlation between phenotype and molecular marker information (r = 0.0043, t = 0.1320, P = 0.5525. The Shannon-Weaver diversity index (I and Nei genetic diversity index (h were higher (I = 0.9537, h = 0.5490 when calculated using phenotypic data from the CC than when using molecular data (I = 0.3467, h = 0.2218. A mini-core collection (MC containing 184 accessions was extracted based on both phenotypic and molecular data, with a low mean difference percentage (MD, 1.64%, low variance difference percentage (VD, 22.58%, large variable rate of coefficient of variance (VR, 114.86%, and large coincidence rate of range (CR, 95.76%. For molecular data, the diversity indices and the polymorphism information content (PIC for the MC were significantly higher than for the CC. Compared to an alternative random sampling strategy, the advantages of capturing genetic diversity and validation by extracting a MC using an advanced maximization strategy were proven. Conclusions This study provides a comprehensive characterization of the phenotypic and molecular genetic diversities of the sesame CC in China. A MC was extracted using both phenotypic and molecular data. Low MD% and VD%, and

Genetic diversity assessment of sesame core collection in China by phenotype and molecular markers and extraction of a mini-core collection

Science.gov (United States)

2012-01-01

Background Sesame (Sesamum indicum L.) is one of the four major oil crops in China. A sesame core collection (CC) was established in China in 2000, but no complete study on its genetic diversity has been carried out at either the phenotypic or molecular level. To provide technical guidance, a theoretical basis for further collection, effective protection, reasonable application, and a complete analysis of sesame genetic resources, a genetic diversity assessment of the sesame CC in China was conducted using phenotypic and molecular data and by extracting a sesame mini-core collection (MC). Results Results from a genetic diversity assessment of sesame CC in China were significantly inconsistent at the phenotypic and molecular levels. A Mantel test revealed the insignificant correlation between phenotype and molecular marker information (r = 0.0043, t = 0.1320, P = 0.5525). The Shannon-Weaver diversity index (I) and Nei genetic diversity index (h) were higher (I = 0.9537, h = 0.5490) when calculated using phenotypic data from the CC than when using molecular data (I = 0.3467, h = 0.2218). A mini-core collection (MC) containing 184 accessions was extracted based on both phenotypic and molecular data, with a low mean difference percentage (MD, 1.64%), low variance difference percentage (VD, 22.58%), large variable rate of coefficient of variance (VR, 114.86%), and large coincidence rate of range (CR, 95.76%). For molecular data, the diversity indices and the polymorphism information content (PIC) for the MC were significantly higher than for the CC. Compared to an alternative random sampling strategy, the advantages of capturing genetic diversity and validation by extracting a MC using an advanced maximization strategy were proven. Conclusions This study provides a comprehensive characterization of the phenotypic and molecular genetic diversities of the sesame CC in China. A MC was extracted using both phenotypic and molecular data. Low MD% and VD%, and large VR% and CR

Chondrosarcoma: With Updates on Molecular Genetics

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Mi-Jung Kim

2011-01-01

Full Text Available Chondrosarcoma (CHS is a malignant cartilage-forming tumor and usually occurs within the medullary canal of long bones and pelvic bones. Based on the morphologic feature alone, a correct diangosis of CHS may be difficult, Therefore, correlation of radiological and clinicopathological features is mandatory in the diagnosis of CHS. The prognosis of CHS is closely related to histologic grading, however, histologic grading may be subjective with high inter-observer variability. In this paper, we present histologic grading system and clinicopathological and radiological findings of conventional CHS. Subtypes of CHSs, such as dedifferentiated, mesenchymal, and clear cell CHSs are also presented. In addition, we introduce updated cytogenetic and molecular genetic findings to expand our understanding of CHS biology. New markers of cell differentiation, proliferation, and cell signaling might offer important therapeutic and prognostic information in near future.

The molecular mechanism of gene-radiotherapy of tumor

International Nuclear Information System (INIS)

Zhu Xian

2004-01-01

Gene-radiotherapy of tumor is a new method which is induced by ionizing radiation. The molecular mechanism is to activate various molecular target by many ways and induce the apoptosis of tumor cell. It is a gene therapy based on the radiation-inducible property of the Egr-1 gene. It has good application prospect in therapy of tumor

[Genetic polymorphism of flax Linum usitatissimum based on use of molecular cytogenetic markers].

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Rachinskaia, O A; Lemesh, V A; Muravenko, O V; Iurkevich, O Iu; Guzenko, E V; Bol'sheva, N L; Bogdanova, M V; Samatadze, T E; Popov, K V; Malyshev, S V; Shostak, N G; Heller, K; Khotyleva, L V; Zelenin, A V

2011-01-01

Using a set of approaches based on the use of molecular cytogenetic markers (DAPI/C-banding, estimation of the total area of DAPI-positive regions in prophase nuclei, FISH with 26S and 5S rDNA probes) and the microsatellite (SSR-PCR) assay, we studied genomic polymorphism in 15 flax (Linum usitatissimum L.) varieties from different geographic regions belonging to three directions of selection (oil, fiber, and intermediate flaxes) and in the k-37 x Viking hybrid. All individual chromosomes have been identified in the karyotypes of these varieties on the basis of the patterns of differential DAPI/C-banding and the distribution of 26S and 5S rDNA, and idiograms of the chromosomes have been generated. Unlike the oil flax varieties, the chromosomes in the karyotypes of the fiber flax varieties have, as a rule, pericentromeric and telomeric DAPI-positive bands of smaller size, but contain larger intercalary regions. Two chromosomal rearrangements (chromosome 3 inversions) were discovered in the variety Luna and in the k-37 x Viking hybrid. In both these forms, no colocalization of 26S rDNA and 5S rDNA on the satellite chromosome was detected. The SSR assay with the use of 20 polymorphic pairs of primers revealed 22 polymorphic loci. Based on the SSR data, we analyzed genetic similarity of the flax forms studied and constructed a genetic similarity dendrogram. The genotypes studied here form three clusters. The oil varieties comprise an independent cluster. The genetically related fiber flax varieties Vita and Luna, as well as the landrace Lipinska XIII belonging to the intermediate type, proved to be closer to the oil varieties than the remaining fiber flax varieties. The results of the molecular chromosomal analysis in the fiber and oil flaxes confirm their very close genetic similarity. In spite of this, the combined use of the chromosomal and molecular markers has opened up unique possibilities for describing the genotypes of flax varieties and creating their genetic

Molecular genetic analysis of a cattle population to reconstitute the extinct Algarvia breed

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Rangel-Figueiredo Teresa

2010-06-01

Full Text Available Abstract Background Decisions to initiate conservation programmes need to account for extant variability, diversity loss and cultural and economic aspects. Molecular markers were used to investigate if putative Algarvia animals could be identified for use as progenitors in a breeding programme to recover this nearly extinct breed. Methods 46 individuals phenotypically representative of Algarvia cattle were genotyped for 27 microsatellite loci and compared with 11 Portuguese autochthonous and three imported breeds. Genetic distances and factorial correspondence analyses (FCA were performed to investigate the relationship among Algarvia and related breeds. Assignment tests were done to identify representative individuals of the breed. Y chromosome and mtDNA analyses were used to further characterize Algarvia animals. Gene- and allelic-based conservation analyses were used to determine breed contributions to overall genetic diversity. Results Genetic distance and FCA results confirmed the close relationship between Algarvia and southern Portuguese breeds. Assignment tests without breed information classified 17 Algarvia animals in this cluster with a high probability (q > 0.95. With breed information, 30 cows and three bulls were identified (q > 0.95 that could be used to reconstitute the Algarvia breed. Molecular and morphological results were concordant. These animals showed intermediate levels of genetic diversity (MNA = 6.0 ± 1.6, Rt = 5.7 ± 1.4, Ho = 0.63 ± 0.19 and He = 0.69 ± 0.10 relative to other Portuguese breeds. Evidence of inbreeding was also detected (Fis = 0.083, P st = 0.028, P > 0.05. Algarvia cattle provide an intermediate contribution (CB = 6.18, CW = -0.06 and D1 = 0.50 to the overall gene diversity of Portuguese cattle. Algarvia and seven other autochthonous breeds made no contribution to the overall allelic diversity. Conclusions Molecular analyses complemented previous morphological findings to identify 33 animals that

A Molecular Genetic Lab to Generate Inclusive and Exclusive Forensic Evidence: Two Suspects, a Victim, and a Bloodstained T-Shirt

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Smit, Julie; Heath, Daniel D.; Walter, Ryan P.

2014-01-01

Molecular genetic laboratory exercises can be ineffective due the student's lack of connection to the complex and sequential protocols. In this inquiry-based molecular genetic laboratory exercise, we harness students' fascination with human forensics and provide a real-life scenario using biomolecular techniques to identify "whose…

Cryptic Genetic Variation in Evolutionary Developmental Genetics

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Annalise B. Paaby

2016-06-01

Full Text Available Evolutionary developmental genetics has traditionally been conducted by two groups: Molecular evolutionists who emphasize divergence between species or higher taxa, and quantitative geneticists who study variation within species. Neither approach really comes to grips with the complexities of evolutionary transitions, particularly in light of the realization from genome-wide association studies that most complex traits fit an infinitesimal architecture, being influenced by thousands of loci. This paper discusses robustness, plasticity and lability, phenomena that we argue potentiate major evolutionary changes and provide a bridge between the conceptual treatments of macro- and micro-evolution. We offer cryptic genetic variation and conditional neutrality as mechanisms by which standing genetic variation can lead to developmental system drift and, sheltered within canalized processes, may facilitate developmental transitions and the evolution of novelty. Synthesis of the two dominant perspectives will require recognition that adaptation, divergence, drift and stability all depend on similar underlying quantitative genetic processes—processes that cannot be fully observed in continuously varying visible traits.

Studying Human Disease Genes in "Caenorhabditis Elegans": A Molecular Genetics Laboratory Project

Science.gov (United States)

Cox-Paulson, Elisabeth A.; Grana, Theresa M.; Harris, Michelle A.; Batzli, Janet M.

2012-01-01

Scientists routinely integrate information from various channels to explore topics under study. We designed a 4-wk undergraduate laboratory module that used a multifaceted approach to study a question in molecular genetics. Specifically, students investigated whether "Caenorhabditis elegans" can be a useful model system for studying genes…

Molecular and genetic aspects of odontogenic tumors: a review.

Science.gov (United States)

Garg, Kavita; Chandra, Shaleen; Raj, Vineet; Fareed, Wamiq; Zafar, Muhammad

2015-06-01

Odontogenic tumors contain a heterogeneous collection of lesions that are categorized from hamartomas to benign and malignant neoplasms of inconstant aggressiveness. Odontogenic tumors are usually extraordinary with assessed frequency of short of 0.5 cases/100,000 population for every year. The lesions such as odontogenic tumors are inferred from the components of the tooth-structuring contraption. They are discovered solely inside the maxillary and mandibular bones. This audit speaks to experiences and cooperation of the molecular and genetic variations connected to the development and movement of odontogenic tumors which incorporate oncogenes, tumor-silencer genes, APC gene, retinoblastoma genes, DNA repair genes, onco-viruses, development components, telomerase, cell cycle controllers, apoptosis-related elements, and regulators/conttrollers of tooth development. The reasonable and better understanding of the molecular components may prompt new ideas for their detection and administrating a better prognosis of odontogenic tumors.

Testicular germ cell tumors: Molecular genetic and clinicomorphological aspects

Directory of Open Access Journals (Sweden)

M. V. Nemtsova

2015-03-01

Full Text Available Testicular tumors are the most common form of solid cancer in young men. According to the 2004 WHO classification, testicular germ cell tumors (TGCT may present with different histological types. Embryonic cells of varying grade may be a source of TGCT and the occurrence of this type of tumors is directly related to the formation of a pool of male sex cells and gametogenesis. The paper gives information on mo- lecular stages for the process of formation of male sex cells in health, as well as ways of their impairments leading to TGCT. An investigation of the profiles of gene expression and the spectrum of molecular damages revealed genes responsible for a predisposition to the sporadic and hereditary forms of TGCT. The paper presents the current molecular genetic and clinicomorphological characteristics of TGCT. 

Candidate gene molecular markers as tools for analyzing genetic susceptibility to morbillivirus infection in stranded Cetaceans

Czech Academy of Sciences Publication Activity Database

Stejskalová, K.; Bayerova, Z.; Futas, J.; Hrazdilová, K.; Klumplerova, M.; Oppelt, J.; Šplíchalová, P.; Di Guardo, G.; Mazzariol, S.; Di Francesco, C. E.; Di Francesco, G.; Terracciano, G.; Paiu, R.M.; Ursache, T. D.; Modrý, David; Horin, P.

2017-01-01

Roč. 90, č. 6 (2017), s. 343-353 ISSN 2059-2302 Institutional support: RVO:60077344 Keywords : Cetacea * haplotype * immunity * innate * mhc-dqb * Phocoena phocoena * polymorphism * single nucleotide * Stenella coeruleoalba Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Biochemistry and molecular biology

Computational exploration of single-protein mechanics by steered molecular dynamics

Energy Technology Data Exchange (ETDEWEB)

Sotomayor, Marcos [Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio (United States)

2015-12-31

Hair cell mechanotransduction happens in tens of microseconds, involves forces of a few picoNewtons, and is mediated by nanometer-scale molecular conformational changes. As proteins involved in this process become identified and their high resolution structures become available, multiple tools are being used to explore their “single-molecule responses” to force. Optical tweezers and atomic force microscopy offer exquisite force and extension resolution, but cannot reach the high loading rates expected for high frequency auditory stimuli. Molecular dynamics (MD) simulations can reach these fast time scales, and also provide a unique view of the molecular events underlying protein mechanics, but its predictions must be experimentally verified. Thus a combination of simulations and experiments might be appropriate to study the molecular mechanics of hearing. Here I review the basics of MD simulations and the different methods used to apply force and study protein mechanics in silico. Simulations of tip link proteins are used to illustrate the advantages and limitations of this method.

Molecular mechanisms underlying the emergence of bacterial pathogens: an ecological perspective.

Science.gov (United States)

Bartoli, Claudia; Roux, Fabrice; Lamichhane, Jay Ram

2016-02-01

The rapid emergence of new bacterial diseases negatively affects both human health and agricultural productivity. Although the molecular mechanisms underlying these disease emergences are shared between human- and plant-pathogenic bacteria, not much effort has been made to date to understand disease emergences caused by plant-pathogenic bacteria. In particular, there is a paucity of information in the literature on the role of environmental habitats in which plant-pathogenic bacteria evolve and on the stress factors to which these microbes are unceasingly exposed. In this microreview, we focus on three molecular mechanisms underlying pathogenicity in bacteria, namely mutations, genomic rearrangements and the acquisition of new DNA sequences through horizontal gene transfer (HGT). We briefly discuss the role of these mechanisms in bacterial disease emergence and elucidate how the environment can influence the occurrence and regulation of these molecular mechanisms by directly impacting disease emergence. The understanding of such molecular evolutionary mechanisms and their environmental drivers will represent an important step towards predicting bacterial disease emergence and developing sustainable management strategies for crops. © 2015 BSPP AND JOHN WILEY & SONS LTD.

Genetic diversity analyses of Lasiodiplodia theobromae on Morus alba and Agave sisalana based on RAPD and ISSR molecular markers

Directory of Open Access Journals (Sweden)

Hong-hui Xie

2016-10-01

Full Text Available Genetic diversity of 23 Lasiodiplodia theobromae isolates on Morus alba and 6 isolates on Agave sisalana in Guangxi province, China, was studied by using random amplified polymorphic DNA and inter-simple sequence repeat molecular markers. Results of two molecular markers showed that the average percentage of polymorphic loci of all isolates was more than 93%. Both dendrograms of two molecular markers showed obvious relationship between groups and the geographical locations where those strains were collected, among which, the 23 isolates on M. alba were divided into 4 populations and the 6 isolates on A. sisalana were separated as a independent population. The average genetic identity and genetic distance of 5 populations were 0.7215, 0.3284 and 0.7915, 0.2347, respectively, which indicated that the genetic identity was high and the genetic distance was short in the 5 populations. Average value of the gene diversity index (H and the Shannon’s information index (I of 29 isolates were significantly higher than 5 populations which showed that genetic diversity of those isolates was richer than the populations and the degree of genetic differentiation of the isolates was higher. The Gst and Nm of 29 isolates were 0.4411, 0.6335 and 0.4756, 0.5513, respectively, which showed that the genetic diversity was rich in those isolates.

Molecular mechanisms of renal aging.

Science.gov (United States)

Schmitt, Roland; Melk, Anette

2017-09-01

Epidemiologic, clinical, and molecular evidence suggest that aging is a major contributor to the increasing incidence of acute kidney injury and chronic kidney disease. The aging kidney undergoes complex changes that predispose to renal pathology. The underlying molecular mechanisms could be the target of therapeutic strategies in the future. Here, we summarize recent insight into cellular and molecular processes that have been shown to contribute to the renal aging phenotype.The main clinical finding of renal aging is the decrease in glomerular filtration rate, and its structural correlate is the loss of functioning nephrons. Mechanistically, this has been linked to different processes, such as podocyte hypertrophy, glomerulosclerosis, tubular atrophy, and gradual microvascular rarefaction. Renal functional recovery after an episode of acute kidney injury is significantly worse in elderly patients. This decreased regenerative potential, which is a hallmark of the aging process, may be caused by cellular senescence. Accumulation of senescent cells could explain insufficient repair and functional loss, a view that has been strengthened by recent studies showing that removal of senescent cells results in attenuation of renal aging. Other potential mechanisms are alterations in autophagy as an important component of a disturbed renal stress response and functional differences in the inflammatory system. Promising therapeutic measures to counteract these age-related problems include mimetics of caloric restriction, pharmacologic renin-angiotensin-aldosterone system inhibition, and novel strategies of senotherapy with the goal of reducing the number of senescent cells to decrease aging-related disease in the kidney. Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

DNA Re-EvolutioN: a game for learning molecular genetics and evolution.

Science.gov (United States)

Miralles, Laura; Moran, Paloma; Dopico, Eduardo; Garcia-Vazquez, Eva

2013-01-01

Evolution is a main concept in biology, but not many students understand how it works. In this article we introduce the game DNA Re-EvolutioN as an active learning tool that uses genetic concepts (DNA structure, transcription and translation, mutations, natural selection, etc.) as playing rules. Students will learn about molecular evolution while playing a game that mixes up theory and entertainment. The game can be easily adapted to different educational levels. The main goal of this play is to arrive at the end of the game with the longest protein. Students play with pawns and dices, a board containing hypothetical events (mutations, selection) that happen to molecules, "Evolution cards" with indications for DNA mutations, prototypes of a DNA and a mRNA chain with colored "nucleotides" (plasticine balls), and small pieces simulating t-RNA with aminoacids that will serve to construct a "protein" based on the DNA chain. Students will understand how changes in DNA affect the final protein product and may be subjected to positive or negative selection, using a didactic tool funnier than classical theory lectures and easier than molecular laboratory experiments: a flexible and feasible game to learn and enjoy molecular evolution at no-cost. The game was tested by majors and non-majors in genetics from 13 different countries and evaluated with pre- and post-tests obtaining very positive results. © 2013 by The International Union of Biochemistry and Molecular Biology.

[Genetics of congenital heart diseases].

Science.gov (United States)

Bonnet, Damien

2017-06-01

Developmental genetics of congenital heart diseases has evolved from analysis of serial slices in embryos towards molecular genetics of cardiac morphogenesis with a dynamic view of cardiac development. Genetics of congenital heart diseases has also changed from formal genetic analysis of familial recurrences or population-based analysis to screening for mutations in candidates genes identified in animal models. Close cooperation between molecular embryologists, pathologists involved in heart development and pediatric cardiologists is crucial for further increase of knowledge in the field of cardiac morphogenesis and genetics of cardiac defects. The genetic model for congenital heart disease has to be revised to favor a polygenic origin rather than a monogenic one. The main mechanism is altered genic dosage that can account for heart diseases in chromosomal anomalies as well as in point mutations in syndromic and isolated congenital heart diseases. The use of big data grouping information from cardiac development, interactions between genes and proteins, epigenetic factors such as chromatin remodeling or DNA methylation is the current source for improving our knowledge in the field and to give clues for future therapies. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Clinical and genetic characterization of six cases with complete ...

Indian Academy of Sciences (India)

JING HE

2017-08-31

Aug 31, 2017 ... The molecular study of the AR gene facilitated the understanding of the mechanism of CAIS and provided the genetic ... recessive genetic disease, which is characterized by par- .... the interaction of AR protein and androgenic hormone. .... in a brazilian cohort: Five novel mutations in the androgen receptor ...

Different routes, same pathways: Molecular mechanisms under silver ion and nanoparticle exposures in the soil sentinel Eisenia fetida

International Nuclear Information System (INIS)

Novo, Marta; Lahive, Elma; Díez-Ortiz, María; Matzke, Marianne; Morgan, Andrew J.; Spurgeon, David J.; Svendsen, Claus; Kille, Peter

2015-01-01

Use of nanotechnology products is increasing; with silver (Ag) nanoparticles particularly widely used. A key uncertainty surrounding the risk assessment of AgNPs is whether their effects are driven through the same mechanism of action that underlies the toxic effects of Ag ions. We present the first full transcriptome study of the effects of Ag ions and NPs in an ecotoxicological model soil invertebrate, the earthworm Eisenia fetida. Gene expression analyses indicated similar mechanisms for both silver forms with toxicity being exerted through pathways related to ribosome function, sugar and protein metabolism, molecular stress, disruption of energy production and histones. The main difference seen between Ag ions and NPs was associated with potential toxicokinetic effects related to cellular internalisation and communication, with pathways related to endocytosis and cilia being significantly enriched. These results point to a common final toxicodynamic response, but initial internalisation driven by different exposure routes and toxicokinetic mechanisms. - Highlights: • Molecular effects underlying Ag ions and NPs exposure were studied in Eisenia fetida. • Full transcriptomic study of a genetically characterised lineage. • NPs and ions presented a similar toxicodynamic response. • Internalisation of the two Ag forms by different toxicokinetic mechanisms. - Transcriptomic analyses after exposure of earthworms to silver NPs or ions showed a final common toxicodynamic response, but internalisation by different toxicokinetic mechanisms

Molecular models of zinc phthalocyanines: semi-empirical molecular orbital computations and physicochemical properties studied by molecular mechanics simulations

International Nuclear Information System (INIS)

Gantchev, Tsvetan G.; van Lier, Johan E.; Hunting, Darel J.

2005-01-01

To build 3D-molecular models of Zinc-phthalocyanines (ZnPc) and to study their diverse chemical and photosensitization properties, we performed quantum mechanical molecular orbital (MO) semi-empirical (AM1) computations of the ground, excited singlet and triplet states as well as free radical (ionic) species. RHF and UHF (open shell) geometry optimizations led to near-perfect symmetrical ZnPc. Predicted ionization potentials (IP), electron affinities (EA) and lowest electronic transitions of ZnPc are in good agreement with the published experimental and theoretical data. The computation-derived D 4h /D 2h -symmetry 3D-structures of ground and excited states and free radicals of ZnPc, together with the frontier orbital energies and Mulliken electron population analysis enabled us to build robust molecular models. These models were used to predict important chemical-reactivity entities such as global electronegativity (χ), hardness (η) and local softness based on Fukui-functions analysis. Examples of molecular mechanics (MM) applications of the 3D-molecular models are presented as approaches to evaluate solvation free energy (ΔG 0 ) solv and to estimate ground- and excited- state oxidation/reduction potentials as well as intermolecular interactions and stability of ground and excited state dimers (exciplexes) and radical ion-pairs

Molecular mechanisms for the destabilization and restabilization of reactivated spatial memory in the Morris water maze

Directory of Open Access Journals (Sweden)

Kim Ryang

2011-02-01

Full Text Available Abstract Background Memory retrieval is not a passive process. Recent studies have shown that reactivated memory is destabilized and then restabilized through gene expression-dependent reconsolidation. Molecular studies on the regulation of memory stability after retrieval have focused almost exclusively on fear memory, especially on the restabilization process of the reactivated fear memory. We previously showed that, similarly with fear memories, reactivated spatial memory undergoes reconsolidation in the Morris water maze. However, the underlying molecular mechanisms by which reactivated spatial memory is destabilized and restabilized remain poorly understood. In this study, we investigated the molecular mechanism that regulates the stability of the reactivated spatial memory. Results We first showed that pharmacological inactivation of the N-methyl-D-aspartate glutamate receptor (NMDAR in the hippocampus or genetic inhibition of cAMP-responsible element binding protein (CREB-mediated transcription disrupted reactivated spatial memory. Finally, we showed that pharmacological inhibition of cannabinoid receptor 1 (CB1 and L-type voltage gated calcium channels (LVGCCs in the hippocampus blocked the disruption of the reactivated spatial memory by the inhibition of protein synthesis. Conclusions Our findings indicated that the reactivated spatial memory is destabilized through the activation of CB1 and LVGCCs and then restabilized through the activation of NMDAR- and CREB-mediated transcription. We also suggest that the reactivated spatial memory undergoes destabilization and restabilization in the hippocampus, through similar molecular processes as those for reactivated contextual fear memories, which require CB1 and LVGCCs for destabilization and NMDAR and CREB for restabilization.

Molecular mechanisms of thermal resistance of the insect trypanosomatid Crithidia thermophilal

Czech Academy of Sciences Publication Activity Database

Ishemgulova, A.; Butenko, A.; Kortišová, L.; Boucinha, C.; Grybchuk-Ieremenko, A.; Morelli, K.A.; Tesařová, Martina; Kraeva, N.; Grybchuk, D.; Pánek, T.; Flegontov, P.; Lukeš, Julius; Votýpka, Jan; Pavan, M. G.; Opperdoes, F. R.; Spodareva, V.; d'Avila-Levy, C.M.; Kostygov, A.Y.; Yurchenko, V.

2017-01-01

Roč. 12, č. 3 (2017), č. článku e0174165. E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GA14-23986S; GA ČR(CZ) GA16-18699S Institutional support: RVO:60077344 Keywords : subunit ribosomal-rna * sp-n * monoxenous trypanosomatids * neotropical heteroptera * mitochondrial hsp70 * paraflagellar rod * genus wallaceina * protein import * costa-rica * parasites Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Biochemistry and molecular biology Impact factor: 2.806, year: 2016

A coordinated molecular 'fishing' mechanism in heterodimeric kinesin

International Nuclear Information System (INIS)

Hou, Ruizheng; Wang, Zhisong

2010-01-01

Kar3 is a kinesin motor that facilitates chromosome segregation during cell division. Unlike many members of the kinesin superfamily, Kar3 forms a heterodimer with non-motor protein Vik1 or Cik1 in vivo. The heterodimers show ATP-driven minus-end directed motility along a microtubule (MT) lattice, and also serve as depolymerase at the MT ends. The molecular mechanisms behind this dual functionality remain mysterious. Here, a molecular mechanical model for the Kar3/Vik1 heterodimer based on structural, kinetic and motility data reveals a long-range chemomechanical transmission mechanism that resembles a familiar fishing tactic. By this molecular 'fishing', ATP-binding to Kar3 dissociates catalytically inactive Vik1 off MT to facilitate minus-end sliding of the dimer on the MT lattice. When the dimer binds the frayed ends of MT, the fishing channels ATP hydrolysis energy into MT deploymerization by a mechanochemical effect. The molecular fishing thus provides a unified mechanistic ground for Kar3's dual functionality. The fishing-promoted depolymerization differs from the depolymerase mechanisms found in homodimeric kinesins. The fishing also enables intermolecular coordination with a chemomechanical coupling feature different from the paradigmatic pattern of homodimeric motors. This study rationalizes some puzzling experimental observation, and suggests new experiments for further elucidation of the fishing mechanism

Joint analysis of phenotypic and molecular diversity provides new insights on the genetic variability of the Brazilian physic nut germplasm bank.

Science.gov (United States)

Alves, Alexandre Alonso; Bhering, Leonardo Lopes; Rosado, Tatiana Barbosa; Laviola, Bruno Galvêas; Formighieri, Eduardo Fernandes; Cruz, Cosme Damião

2013-09-01

The genetic variability of the Brazilian physic nut (Jatropha curcas) germplasm bank (117 accessions) was assessed using a combination of phenotypic and molecular data. The joint dissimilarity matrix showed moderate correlation with the original matrices of phenotypic and molecular data. However, the correlation between the phenotypic dissimilarity matrix and the genotypic dissimilarity matrix was low. This finding indicated that molecular markers (RAPD and SSR) did not adequately sample the genomic regions that were relevant for phenotypic differentiation of the accessions. The dissimilarity values of the joint dissimilarity matrix were used to measure phenotypic + molecular diversity. This diversity varied from 0 to 1.29 among the 117 accessions, with an average dissimilarity among genotypes of 0.51. Joint analysis of phenotypic and molecular diversity indicated that the genetic diversity of the physic nut germplasm was 156% and 64% higher than the diversity estimated from phenotypic and molecular data, respectively. These results show that Jatropha genetic variability in Brazil is not as limited as previously thought.

Mechanisms of two-color laser-induced field-free molecular orientation.

Science.gov (United States)

Spanner, Michael; Patchkovskii, Serguei; Frumker, Eugene; Corkum, Paul

2012-09-14

Two mechanisms of two-color (ω+2ω) laser-induced field-free molecular orientation, based on the hyperpolarizability and ionization depletion, are explored and compared. The CO molecule is used as a computational example. While the hyperpolarizability mechanism generates small amounts of orientation at intensities below the ionization threshold, ionization depletion quickly becomes the dominant mechanism as soon as ionizing intensities are reached. Only the ionization mechanism leads to substantial orientation (e.g., on the order of ≳0.1). For intensities typical of laser-induced molecular alignment and orientation experiments, the two mechanisms lead to robust, characteristic timings of the field-free orientation wave-packet revivals relative to the alignment revivals and the revival time. The revival timings can be used to detect the active orientation mechanism experimentally.

Molecular Mechanisms of Neuroplasticity: An Expanding Universe.

Science.gov (United States)

Gulyaeva, N V

2017-03-01

Biochemical processes in synapses and other neuronal compartments underlie neuroplasticity (functional and structural alterations in the brain enabling adaptation to the environment, learning, memory, as well as rehabilitation after brain injury). This basic molecular level of brain plasticity covers numerous specific proteins (enzymes, receptors, structural proteins, etc.) participating in many coordinated and interacting signal and metabolic processes, their modulation forming a molecular basis for brain plasticity. The articles in this issue are focused on different "hot points" in the research area of biochemical mechanisms supporting neuroplasticity.

Molecular and genetic aspects of odontogenic tumors: a review

Directory of Open Access Journals (Sweden)

Kavita Garg

2015-06-01

Full Text Available Odontogenic tumors contain a heterogeneous collection of lesions that are categorized from hamartomas to benign and malignant neoplasms of inconstant aggressiveness. Odontogenic tumors are usually extraordinary with assessed frequency of short of 0.5 cases/100,000 population for every year. The lesions such as odontogenic tumors are inferred from the components of the tooth-structuring contraption. They are discovered solely inside the maxillary and mandibular bones. This audit speaks to experiences and cooperation of the molecular and genetic variations connected to the development and movement of odontogenic tumors which incorporate oncogenes, tumor-silencer genes, APC gene, retinoblastoma genes, DNA repair genes, onco-viruses, development components, telomerase, cell cycle controllers, apoptosis-related elements, and regulators/controllers of tooth development. The reasonable and better understanding of the molecular components may prompt new ideas for their detection and administrating a better prognosis of odontogenic tumors.

Pathogenesis of Gastric Cancer: Genetics and Molecular Classification.

Science.gov (United States)

Figueiredo, Ceu; Camargo, M C; Leite, Marina; Fuentes-Pananá, Ezequiel M; Rabkin, Charles S; Machado, José C

Gastric cancer is the fifth most incident and the third most common cause of cancer-related death in the world. Infection with Helicobacter pylori is the major risk factor for this disease. Gastric cancer is the final outcome of a cascade of events that takes decades to occur and results from the accumulation of multiple genetic and epigenetic alterations. These changes are crucial for tumor cells to expedite and sustain the array of pathways involved in the cancer development, such as cell cycle, DNA repair, metabolism, cell-to-cell and cell-to-matrix interactions, apoptosis, angiogenesis, and immune surveillance. Comprehensive molecular analyses of gastric cancer have disclosed the complex heterogeneity of this disease. In particular, these analyses have confirmed that Epstein-Barr virus (EBV)-positive gastric cancer is a distinct entity. The identification of gastric cancer subtypes characterized by recognizable molecular profiles may pave the way for a more personalized clinical management and to the identification of novel therapeutic targets and biomarkers for screening, prognosis, prediction of response to treatment, and monitoring of gastric cancer progression.

Primordial dwarfism: overview of clinical and genetic aspects.

Science.gov (United States)

Khetarpal, Preeti; Das, Satrupa; Panigrahi, Inusha; Munshi, Anjana

2016-02-01

Primordial dwarfism is a group of genetic disorders which include Seckel Syndrome, Silver-Russell Syndrome, Microcephalic Osteodysplastic Primordial Dwarfism types I/III, II and Meier-Gorlin Syndrome. This genetic disorder group is characterized by intra-uterine growth retardation and post-natal growth abnormalities which occur as a result of disorganized molecular and genomic changes in embryonic stage and, thus, it represents a unique area to study growth and developmental abnormalities. Lot of research has been carried out on different aspects; however, a consolidated review that discusses an overall spectrum of this disorder is not accessible. Recent research in this area points toward important molecular and cellular mechanisms in human body that regulate the complexity of growth process. Studies have emerged that have clearly associated with a number of abnormal chromosomal, genetic and epigenetic alterations that can predispose an embryo to develop PD-associated developmental defects. Finding and associating such fundamental changes to its subtypes will help in re-examination of alleged functions at both cellular and developmental levels and thus reveal the intrinsic mechanism that leads to a balanced growth. Although such findings have unraveled a subtle understanding of growth process, we further require active research in terms of identification of reliable biomarkers for different subtypes as an immediate requirement for clinical utilization. It is hoped that further study will advance the understanding of basic mechanisms regulating growth relevant to human health. Therefore, this review has been written with an aim to present an overview of chromosomal, molecular and epigenetic modifications reported to be associated with different subtypes of this heterogenous disorder. Further, latest findings with respect to clinical and molecular genetics research have been summarized to aid the medical fraternity in their clinical utility, for diagnosing disorders

Institute of Genetics and of Toxicology of Fissile Materials. Progress report on research and development work in 1992

International Nuclear Information System (INIS)

1993-03-01

In the year under report, the institute's scope of investigations comprised the seven topics surveyed in the following together with the most recent research results obtained. These were genetic repair and genetic regulation mechanisms, biologic carcinogenesis, molecular genetics of eukaryotic genes, genetic mouse models of human disorders, toxicology of radioactive and non-radioactive heavy metals as well as environmental toxicology at the molecular and cellular levels. (orig./MG) [de

Molecular mechanisms of curcumin action: gene expression.

Science.gov (United States)

Shishodia, Shishir

2013-01-01

Curcumin derived from the tropical plant Curcuma longa has a long history of use as a dietary agent, food preservative, and in traditional Asian medicine. It has been used for centuries to treat biliary disorders, anorexia, cough, diabetic wounds, hepatic disorders, rheumatism, and sinusitis. The preventive and therapeutic properties of curcumin are associated with its antioxidant, anti-inflammatory, and anticancer properties. Extensive research over several decades has attempted to identify the molecular mechanisms of curcumin action. Curcumin modulates numerous molecular targets by altering their gene expression, signaling pathways, or through direct interaction. Curcumin regulates the expression of inflammatory cytokines (e.g., TNF, IL-1), growth factors (e.g., VEGF, EGF, FGF), growth factor receptors (e.g., EGFR, HER-2, AR), enzymes (e.g., COX-2, LOX, MMP9, MAPK, mTOR, Akt), adhesion molecules (e.g., ELAM-1, ICAM-1, VCAM-1), apoptosis related proteins (e.g., Bcl-2, caspases, DR, Fas), and cell cycle proteins (e.g., cyclin D1). Curcumin modulates the activity of several transcription factors (e.g., NF-κB, AP-1, STAT) and their signaling pathways. Based on its ability to affect multiple targets, curcumin has the potential for the prevention and treatment of various diseases including cancers, arthritis, allergies, atherosclerosis, aging, neurodegenerative disease, hepatic disorders, obesity, diabetes, psoriasis, and autoimmune diseases. This review summarizes the molecular mechanisms of modulation of gene expression by curcumin. Copyright © 2012 International Union of Biochemistry and Molecular Biology, Inc.

Molecular Dynamics Simulations with Quantum Mechanics/Molecular Mechanics and Adaptive Neural Networks.

Science.gov (United States)

Shen, Lin; Yang, Weitao

2018-03-13

Direct molecular dynamics (MD) simulation with ab initio quantum mechanical and molecular mechanical (QM/MM) methods is very powerful for studying the mechanism of chemical reactions in a complex environment but also very time-consuming. The computational cost of QM/MM calculations during MD simulations can be reduced significantly using semiempirical QM/MM methods with lower accuracy. To achieve higher accuracy at the ab initio QM/MM level, a correction on the existing semiempirical QM/MM model is an attractive idea. Recently, we reported a neural network (NN) method as QM/MM-NN to predict the potential energy difference between semiempirical and ab initio QM/MM approaches. The high-level results can be obtained using neural network based on semiempirical QM/MM MD simulations, but the lack of direct MD samplings at the ab initio QM/MM level is still a deficiency that limits the applications of QM/MM-NN. In the present paper, we developed a dynamic scheme of QM/MM-NN for direct MD simulations on the NN-predicted potential energy surface to approximate ab initio QM/MM MD. Since some configurations excluded from the database for NN training were encountered during simulations, which may cause some difficulties on MD samplings, an adaptive procedure inspired by the selection scheme reported by Behler [ Behler Int. J. Quantum Chem. 2015 , 115 , 1032 ; Behler Angew. Chem., Int. Ed. 2017 , 56 , 12828 ] was employed with some adaptions to update NN and carry out MD iteratively. We further applied the adaptive QM/MM-NN MD method to the free energy calculation and transition path optimization on chemical reactions in water. The results at the ab initio QM/MM level can be well reproduced using this method after 2-4 iteration cycles. The saving in computational cost is about 2 orders of magnitude. It demonstrates that the QM/MM-NN with direct MD simulations has great potentials not only for the calculation of thermodynamic properties but also for the characterization of

Genetic diversity and molecular evolution of Ornithogalum mosaic virus based on the coat protein gene sequence

Directory of Open Access Journals (Sweden)

Fangluan Gao

2018-03-01

Full Text Available Ornithogalum mosaic virus (OrMV has a wide host range and affects the production of a variety of ornamentals. In this study, the coat protein (CP gene of OrMVwas used to investigate the molecular mechanisms underlying the evolution of this virus. The 36 OrMV isolates fell into two groups which have significant subpopulation differentiation with an FST value of 0.470. One isolate was identified as a recombinant and the other 35 recombination-free isolates could be divided into two major clades under different evolutionary constraints with dN/dS values of 0.055 and 0.028, respectively, indicating a role of purifying selection in the differentiation of OrMV. In addition, the results from analysis of molecular variance (AMOVA indicated that the effect of host species on the genetic divergence of OrMV is greater than that of geography. Furthermore, OrMV isolates from the genera Ornithogalum, Lachenalia and Diuri tended to group together, indicating that OrMV diversification was maintained, in part, by host-driven adaptation.

Unraveling the Root Proteome Changes and Its Relationship to Molecular Mechanism Underlying Salt Stress Response in Radish (Raphanus sativus L.

Directory of Open Access Journals (Sweden)

Xiaochuan Sun

2017-07-01

Full Text Available To understand the molecular mechanism underlying salt stress response in radish, iTRAQ-based proteomic analysis was conducted to investigate the differences in protein species abundance under different salt treatments. In total, 851, 706, and 685 differential abundance protein species (DAPS were identified between CK vs. Na100, CK vs. Na200, and Na100 vs. Na200, respectively. Functional annotation analysis revealed that salt stress elicited complex proteomic alterations in radish roots involved in carbohydrate and energy metabolism, protein metabolism, signal transduction, transcription regulation, stress and defense and transport. Additionally, the expression levels of nine genes encoding DAPS were further verified using RT-qPCR. The integrative analysis of transcriptomic and proteomic data in conjunction with miRNAs was further performed to strengthen the understanding of radish response to salinity. The genes responsible for signal transduction, ROS scavenging and transport activities as well as several key miRNAs including miR171, miR395, and miR398 played crucial roles in salt stress response in radish. Based on these findings, a schematic genetic regulatory network of salt stress response was proposed. This study provided valuable insights into the molecular mechanism underlying salt stress response in radish roots and would facilitate developing effective strategies toward genetically engineered salt-tolerant radish and other root vegetable crops.

Genetic instability in budding and fission yeast—sources and mechanisms

Science.gov (United States)

Skoneczna, Adrianna; Kaniak, Aneta; Skoneczny, Marek

2015-01-01

Cells are constantly confronted with endogenous and exogenous factors that affect their genomes. Eons of evolution have allowed the cellular mechanisms responsible for preserving the genome to adjust for achieving contradictory objectives: to maintain the genome unchanged and to acquire mutations that allow adaptation to environmental changes. One evolutionary mechanism that has been refined for survival is genetic variation. In this review, we describe the mechanisms responsible for two biological processes: genome maintenance and mutation tolerance involved in generations of genetic variations in mitotic cells of both Saccharomyces cerevisiae and Schizosaccharomyces pombe. These processes encompass mechanisms that ensure the fidelity of replication, DNA lesion sensing and DNA damage response pathways, as well as mechanisms that ensure precision in chromosome segregation during cell division. We discuss various factors that may influence genome stability, such as cellular ploidy, the phase of the cell cycle, transcriptional activity of a particular region of DNA, the proficiency of DNA quality control systems, the metabolic stage of the cell and its respiratory potential, and finally potential exposure to endogenous or environmental stress. PMID:26109598

Molecular markers to assess genetic diversity and mutant identifications in Jatropha curcas

International Nuclear Information System (INIS)

Azhar Mohamad; Yie Min Kwan; Fatin Mastura Derani; Abdul Rahim Harun

2010-01-01

Jatropha curcas (Linnaeus) belongs to the Euphorbiaceae family, is a multipurpose use, drought resistant and perennial plant. It is an economic important crop, which generates wide interest in understanding the genetic diversity of the species towards selection and breeding of superior genotypes. Jatropha accessions are closely related family species. Thus, better understanding of the effectiveness of the different DNA-based markers is an important step towards plant germplasm characterization and evaluation. It is becoming a prerequisite for more effective application of marker techniques in breeding programs. Inter-simple sequence repeats (ISSRs) has shown rapid, simple, reproducible and inexpensive means in molecular taxonomy, conservation breeding and genetic diversity analysis. These markers were used to understand diversity and differentiate amongst accessions of Jatropha population and mutant lines generated by acute gamma radiation. The ISSR for marker applications are essential to facilitate management, conservation and genetic improvement programs towards improvement of bio-diesel production and medication substances. A total of 62 ISSR primers were optimized for polymorphism evaluations on five foreign accessions (Africa, India, Myanmar, Indonesia, Thailand), nine local accessions and two mutants of Jatropha. Optimization was resulted 54 ISSR primers affirmative for the polymorphism evaluation study, which encountered 12 ISSR primers, showed significance polymorphism amongst the accessions and mutants. Marker derived from ISSR profiling is a powerful method for identification and molecular classification of Jatropha from accession to generated mutant varieties. (author)

A Molecular Dynamics (MD) and Quantum Mechanics/Molecular Mechanics (QM/MM) Study on Ornithine Cyclodeaminase (OCD): A Tale of Two Iminiums

Science.gov (United States)

Ion, Bogdan F.; Bushnell, Eric A. C.; De Luna, Phil; Gauld, James W.

2012-01-01

Ornithine cyclodeaminase (OCD) is an NAD+-dependent deaminase that is found in bacterial species such as Pseudomonas putida. Importantly, it catalyzes the direct conversion of the amino acid L-ornithine to L-proline. Using molecular dynamics (MD) and a hybrid quantum mechanics/molecular mechanics (QM/MM) method in the ONIOM formalism, the catalytic mechanism of OCD has been examined. The rate limiting step is calculated to be the initial step in the overall mechanism: hydride transfer from the L-ornithine’s Cα–H group to the NAD+ cofactor with concomitant formation of a Cα=NH2 + Schiff base with a barrier of 90.6 kJ mol−1. Importantly, no water is observed within the active site during the MD simulations suitably positioned to hydrolyze the Cα=NH2 + intermediate to form the corresponding carbonyl. Instead, the reaction proceeds via a non-hydrolytic mechanism involving direct nucleophilic attack of the δ-amine at the Cα-position. This is then followed by cleavage and loss of the α-NH2 group to give the Δ1-pyrroline-2-carboxylate that is subsequently reduced to L-proline. PMID:23202934

A Molecular Dynamics (MD and Quantum Mechanics/Molecular Mechanics (QM/MM Study on Ornithine Cyclodeaminase (OCD: A Tale of Two Iminiums

Directory of Open Access Journals (Sweden)

James W. Gauld

2012-10-01

Full Text Available Ornithine cyclodeaminase (OCD is an NAD+-dependent deaminase that is found in bacterial species such as Pseudomonas putida. Importantly, it catalyzes the direct conversion of the amino acid L-ornithine to L-proline. Using molecular dynamics (MD and a hybrid quantum mechanics/molecular mechanics (QM/MM method in the ONIOM formalism, the catalytic mechanism of OCD has been examined. The rate limiting step is calculated to be the initial step in the overall mechanism: hydride transfer from the L-ornithine’s Cα–H group to the NAD+ cofactor with concomitant formation of a Cα=NH2+ Schiff base with a barrier of 90.6 kJ mol−1. Importantly, no water is observed within the active site during the MD simulations suitably positioned to hydrolyze the Cα=NH2+ intermediate to form the corresponding carbonyl. Instead, the reaction proceeds via a non-hydrolytic mechanism involving direct nucleophilic attack of the δ-amine at the Cα-position. This is then followed by cleavage and loss of the α-NH2 group to give the Δ1-pyrroline-2-carboxylate that is subsequently reduced to L-proline.

Molecular mechanism of Endosulfan action in mammals

Indian Academy of Sciences (India)

Keywords. DNA damage; double-strand break; genomic instability; infertility; MMEJ; NHEJ; pesticides. Abstract. Endosulfan is a broad-spectrum organochlorine pesticide, speculated to be detrimental to human health in areas ofactive exposure. However, the molecular insights to its mechanism of action remain poorly ...

Prediction of Sliding Friction Coefficient Based on a Novel Hybrid Molecular-Mechanical Model.

Science.gov (United States)

Zhang, Xiaogang; Zhang, Yali; Wang, Jianmei; Sheng, Chenxing; Li, Zhixiong

2018-08-01

Sliding friction is a complex phenomenon which arises from the mechanical and molecular interactions of asperities when examined in a microscale. To reveal and further understand the effects of micro scaled mechanical and molecular components of friction coefficient on overall frictional behavior, a hybrid molecular-mechanical model is developed to investigate the effects of main factors, including different loads and surface roughness values, on the sliding friction coefficient in a boundary lubrication condition. Numerical modelling was conducted using a deterministic contact model and based on the molecular-mechanical theory of friction. In the contact model, with given external loads and surface topographies, the pressure distribution, real contact area, and elastic/plastic deformation of each single asperity contact were calculated. Then asperity friction coefficient was predicted by the sum of mechanical and molecular components of friction coefficient. The mechanical component was mainly determined by the contact width and elastic/plastic deformation, and the molecular component was estimated as a function of the contact area and interfacial shear stress. Numerical results were compared with experimental results and a good agreement was obtained. The model was then used to predict friction coefficients in different operating and surface conditions. Numerical results explain why applied load has a minimum effect on the friction coefficients. They also provide insight into the effect of surface roughness on the mechanical and molecular components of friction coefficients. It is revealed that the mechanical component dominates the friction coefficient when the surface roughness is large (Rq > 0.2 μm), while the friction coefficient is mainly determined by the molecular component when the surface is relatively smooth (Rq < 0.2 μm). Furthermore, optimal roughness values for minimizing the friction coefficient are recommended.

Integrated molecular landscape of Parkinson's disease

NARCIS (Netherlands)

Klemann, C.J.H.M.; Martens, G.J.; Sharma, M.; Martens, M.B.; Isacson, O.; Gasser, T.; Visser, J.E.; Poelmans, G.J.V.

2017-01-01

Parkinson's disease is caused by a complex interplay of genetic and environmental factors. Although a number of independent molecular pathways and processes have been associated with familial Parkinson's disease, a common mechanism underlying especially sporadic Parkinson's disease is still largely

Genetic, functional and molecular features of glucocorticoid receptor binding.

Directory of Open Access Journals (Sweden)

Francesca Luca

Full Text Available Glucocorticoids (GCs are key mediators of stress response and are widely used as pharmacological agents to treat immune diseases, such as asthma and inflammatory bowel disease, and certain types of cancer. GCs act mainly by activating the GC receptor (GR, which interacts with other transcription factors to regulate gene expression. Here, we combined different functional genomics approaches to gain molecular insights into the mechanisms of action of GC. By profiling the transcriptional response to GC over time in 4 Yoruba (YRI and 4 Tuscans (TSI lymphoblastoid cell lines (LCLs, we suggest that the transcriptional response to GC is variable not only in time, but also in direction (positive or negative depending on the presence of specific interacting transcription factors. Accordingly, when we performed ChIP-seq for GR and NF-κB in two YRI LCLs treated with GC or with vehicle control, we observed that features of GR binding sites differ for up- and down-regulated genes. Finally, we show that eQTLs that affect expression patterns only in the presence of GC are 1.9-fold more likely to occur in GR binding sites, compared to eQTLs that affect expression only in its absence. Our results indicate that genetic variation at GR and interacting transcription factors binding sites influences variability in gene expression, and attest to the power of combining different functional genomic approaches.

Chemical and mechanical efficiencies of molecular motors and implications for motor mechanisms

International Nuclear Information System (INIS)

Wang Hongyun

2005-01-01

Molecular motors operate in an environment dominated by viscous friction and thermal fluctuations. The chemical reaction in a motor may produce an active force at the reaction site to directly move the motor forward. Alternatively a molecular motor may generate a unidirectional motion by rectifying thermal fluctuations using free energy barriers established in the chemical reaction. The reaction cycle has many occupancy states, each having a different effect on the motor motion. The average effect of the chemical reaction on the motor motion can be characterized by the motor potential profile. The biggest advantage of studying the motor potential profile is that it can be reconstructed from the time series of motor positions measured in single-molecule experiments. In this paper, we use the motor potential profile to express the Stokes efficiency as the product of the chemical efficiency and the mechanical efficiency. We show that both the chemical and mechanical efficiencies are bounded by 100% and, thus, are properly defined efficiencies. We discuss implications of high efficiencies for motor mechanisms: a mechanical efficiency close to 100% implies that the motor potential profile is close to a constant slope; a chemical efficiency close to 100% implies that (i) the chemical transitions are not slower than the mechanical motion and (ii) the equilibrium constant of each chemical transition is close to one

Genetic characterization, molecular epidemiology, and phylogenetic relationships of insect-specific viruses in the taxon Negevirus.

Science.gov (United States)

Nunes, Marcio R T; Contreras-Gutierrez, María Angélica; Guzman, Hilda; Martins, Livia C; Barbirato, Mayla Feitoza; Savit, Chelsea; Balta, Victoria; Uribe, Sandra; Vivero, Rafael; Suaza, Juan David; Oliveira, Hamilton; Nunes Neto, Joaquin P; Carvalho, Valeria L; da Silva, Sandro Patroca; Cardoso, Jedson F; de Oliveira, Rodrigo Santo; da Silva Lemos, Poliana; Wood, Thomas G; Widen, Steven G; Vasconcelos, Pedro F C; Fish, Durland; Vasilakis, Nikos; Tesh, Robert B

2017-04-01

The recently described taxon Negevirus is comprised of a diverse group of insect-specific viruses isolated from mosquitoes and phlebotomine sandflies. In this study, a comprehensive genetic characterization, molecular, epidemiological and evolutionary analyses were conducted on nearly full-length sequences of 91 new negevirus isolates obtained in Brazil, Colombia, Peru, Panama, USA and Nepal. We demonstrated that these arthropod restricted viruses are clustered in two major phylogenetic groups with origins related to three plant virus genera (Cilevirus, Higrevirus and Blunevirus). Molecular analyses demonstrated that specific host correlations are not present with most negeviruses; instead, high genetic variability, wide host-range, and cross-species transmission were noted. The data presented here also revealed the existence of five novel insect-specific viruses falling into two arthropod-restrictive virus taxa, previously proposed as distinct genera, designated Nelorpivirus and Sandewavirus. Our results provide a better understanding of the molecular epidemiology, evolution, taxonomy and stability of this group of insect-restricted viruses. Copyright © 2017 Elsevier Inc. All rights reserved.

Genetic Confirmation of Mungbean (Vigna radiata) and Mashbean (Vigna mungo) Interspecific Recombinants using Molecular Markers.

Science.gov (United States)

Abbas, Ghulam; Hameed, Amjad; Rizwan, Muhammad; Ahsan, Muhammad; Asghar, Muhammad J; Iqbal, Nayyer

2015-01-01

Molecular confirmation of interspecific recombinants is essential to overcome the issues like self-pollination, environmental influence, and inadequacy of morphological characteristics during interspecific hybridization. The present study was conducted for genetic confirmation of mungbean (female) and mashbean (male) interspecific crosses using molecular markers. Initially, polymorphic random amplified polymorphic DNA (RAPD), universal rice primers (URP), and simple sequence repeats (SSR) markers differentiating parent genotypes were identified. Recombination in hybrids was confirmed using these polymorphic DNA markers. The NM 2006 × Mash 88 was most successful interspecific cross. Most of true recombinants confirmed by molecular markers were from this cross combination. SSR markers were efficient in detecting genetic variability and recombination with reference to specific chromosomes and particular loci. SSR (RIS) and RAPD identified variability dispersed throughout the genome. In conclusion, DNA based marker assisted selection (MAS) efficiently confirmed the interspecific recombinants. The results provided evidence that MAS can enhance the authenticity of selection in mungbean improvement program.

A Practical Quantum Mechanics Molecular Mechanics Method for the Dynamical Study of Reactions in Biomolecules.

Science.gov (United States)

Mendieta-Moreno, Jesús I; Marcos-Alcalde, Iñigo; Trabada, Daniel G; Gómez-Puertas, Paulino; Ortega, José; Mendieta, Jesús

2015-01-01

Quantum mechanics/molecular mechanics (QM/MM) methods are excellent tools for the modeling of biomolecular reactions. Recently, we have implemented a new QM/MM method (Fireball/Amber), which combines an efficient density functional theory method (Fireball) and a well-recognized molecular dynamics package (Amber), offering an excellent balance between accuracy and sampling capabilities. Here, we present a detailed explanation of the Fireball method and Fireball/Amber implementation. We also discuss how this tool can be used to analyze reactions in biomolecules using steered molecular dynamics simulations. The potential of this approach is shown by the analysis of a reaction catalyzed by the enzyme triose-phosphate isomerase (TIM). The conformational space and energetic landscape for this reaction are analyzed without a priori assumptions about the protonation states of the different residues during the reaction. The results offer a detailed description of the reaction and reveal some new features of the catalytic mechanism. In particular, we find a new reaction mechanism that is characterized by the intramolecular proton transfer from O1 to O2 and the simultaneous proton transfer from Glu 165 to C2. Copyright © 2015 Elsevier Inc. All rights reserved.

Insight into the Mechanism of Hydrolysis of Meropenem by OXA-23 Serine-β-lactamase Gained by Quantum Mechanics/Molecular Mechanics Calculations.

Science.gov (United States)

Sgrignani, Jacopo; Grazioso, Giovanni; De Amici, Marco

2016-09-13

The fast and constant development of drug resistant bacteria represents a serious medical emergency. To overcome this problem, the development of drugs with new structures and modes of action is urgently needed. In this work, we investigated, at the atomistic level, the mechanisms of hydrolysis of Meropenem by OXA-23, a class D β-lactamase, combining unbiased classical molecular dynamics and umbrella sampling simulations with classical force field-based and quantum mechanics/molecular mechanics potentials. Our calculations provide a detailed structural and dynamic picture of the molecular steps leading to the formation of the Meropenem-OXA-23 covalent adduct, the subsequent hydrolysis, and the final release of the inactive antibiotic. In this mechanistic framework, the predicted activation energy is in good agreement with experimental kinetic measurements, validating the expected reaction path.

Symposium on molecular and cellular mechanisms of mutagenesis

International Nuclear Information System (INIS)

1981-01-01

These proceedings contain abstracts only of the 21 papers presented at the Sympsoium. The papers dealt with molecular mechanisms of mutagenesis and cellular responses to chemical and physical mutagenic agents

Theoretical modeling of large molecular systems. Advances in the local self consistent field method for mixed quantum mechanics/molecular mechanics calculations.

Science.gov (United States)

Monari, Antonio; Rivail, Jean-Louis; Assfeld, Xavier

2013-02-19

Molecular mechanics methods can efficiently compute the macroscopic properties of a large molecular system but cannot represent the electronic changes that occur during a chemical reaction or an electronic transition. Quantum mechanical methods can accurately simulate these processes, but they require considerably greater computational resources. Because electronic changes typically occur in a limited part of the system, such as the solute in a molecular solution or the substrate within the active site of enzymatic reactions, researchers can limit the quantum computation to this part of the system. Researchers take into account the influence of the surroundings by embedding this quantum computation into a calculation of the whole system described at the molecular mechanical level, a strategy known as the mixed quantum mechanics/molecular mechanics (QM/MM) approach. The accuracy of this embedding varies according to the types of interactions included, whether they are purely mechanical or classically electrostatic. This embedding can also introduce the induced polarization of the surroundings. The difficulty in QM/MM calculations comes from the splitting of the system into two parts, which requires severing the chemical bonds that link the quantum mechanical subsystem to the classical subsystem. Typically, researchers replace the quantoclassical atoms, those at the boundary between the subsystems, with a monovalent link atom. For example, researchers might add a hydrogen atom when a C-C bond is cut. This Account describes another approach, the Local Self Consistent Field (LSCF), which was developed in our laboratory. LSCF links the quantum mechanical portion of the molecule to the classical portion using a strictly localized bond orbital extracted from a small model molecule for each bond. In this scenario, the quantoclassical atom has an apparent nuclear charge of +1. To achieve correct bond lengths and force constants, we must take into account the inner shell of

Molecular mechanisms for protein-encoded inheritance

Science.gov (United States)

Wiltzius, Jed J. W.; Landau, Meytal; Nelson, Rebecca; Sawaya, Michael R.; Apostol, Marcin I.; Goldschmidt, Lukasz; Soriaga, Angela B.; Cascio, Duilio; Rajashankar, Kanagalaghatta; Eisenberg, David

2013-01-01

Strains are phenotypic variants, encoded by nucleic acid sequences in chromosomal inheritance and by protein “conformations” in prion inheritance and transmission. But how is a protein “conformation” stable enough to endure transmission between cells or organisms? Here new polymorphic crystal structures of segments of prion and other amyloid proteins offer structural mechanisms for prion strains. In packing polymorphism, prion strains are encoded by alternative packings (polymorphs) of β-sheets formed by the same segment of a protein; in a second mechanism, segmental polymorphism, prion strains are encoded by distinct β-sheets built from different segments of a protein. Both forms of polymorphism can produce enduring “conformations,” capable of encoding strains. These molecular mechanisms for transfer of information into prion strains share features with the familiar mechanism for transfer of information by nucleic acid inheritance, including sequence specificity and recognition by non-covalent bonds. PMID:19684598

Fanconi anaemia: genetics, molecular biology, and cancer – implications for clinical management in children and adults.

Science.gov (United States)

Schneider, M; Chandler, K; Tischkowitz, M; Meyer, S

2015-07-01

Fanconi anaemia (FA) is an inherited disease with congenital and developmental abnormalities, cross-linker hypersensitivity and extreme cancer predisposition. With better understanding of the genetic and molecular basis of the disease, and improved clinical management, FA has been transformed from a life-limiting paediatric disease to an uncommon chronic condition that needs lifelong multidisciplinary management, and a paradigm condition for the understanding of the gene-environment interaction in the aetiology of congenital anomalies, haematopoiesis and cancer development. Here we review genetic, molecular and clinical aspects of FA, and discuss current controversies and future prospects. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Synovial sarcoma with radiological appearances of primitive neuroectodermal tumour/Ewing sarcoma: differentiation by molecular genetic studies

International Nuclear Information System (INIS)

O'Donnell, P.; Diss, T.C.; Whelan, J.; Flanagan, A.M.

2006-01-01

Synovial sarcoma (SS) arises in soft tissues but may invade adjacent bone. We describe a case of SS presenting as aggressive lysis of the proximal ulna, the imaging of which suggested a primary bone lesion. Needle biopsy showed a 'small round blue cell tumour', and a primitive neuroectodermal tumour (PNET)/Ewing sarcoma was suggested on the basis of the imaging appearances. The definitive diagnosis of synovial sarcoma was made following molecular genetic studies, which demonstrated a fusion product incorporating the genes SYT and SSX1. The importance of correct diagnosis to guide appropriate management, and, therefore, the necessity for molecular genetic studies, is discussed. (orig.)

Symposium on molecular and cellular mechanisms of mutagenesis

Energy Technology Data Exchange (ETDEWEB)

1981-01-01

These proceedings contain abstracts only of the 21 papers presented at the Sympsoium. The papers dealt with molecular mechanisms of mutagenesis and cellular responses to chemical and physical mutagenic agents. (ERB)

MODY in Siberia – molecular genetics and clinical characteristics

Directory of Open Access Journals (Sweden)

Alla Konstantinovna Ovsyannikova

2017-05-01

Full Text Available The diagnosis of maturity onset diabetes of the young (MODY has high clinical significance in young patients (no absolute need for exogenous insulin; normoglycaemia in most patients achieved by dieting or taking oral hypoglycaemic agents and their relatives (high probability of first-degree relatives being carriers of mutations, which requires a thorough collection of family history and determination of the parameters of carbohydrate metabolism. Aim. This study aimed was to determine the clinical characteristics of different subtypes of MODY in a Siberian region. Materials and Methods. We performed an examination, biochemical and hormonal blood tests, ultrasound and molecular genetic testing of 20 patients with a clinical diagnosis of MODY. Results. Four subtypes of MODY were verified: MODY2 in 11 patients, MODY3 in two, MODY8 in one and MODY12 in two. Eleven patients (69% exhibited no clinical manifestations of carbohydrate metabolism disorders, and one patient showed weight loss during early stage of the disease. Comorbidities included dyslipidemia, thyroid gland disorders and arterial hypertension. One patient (6% exhibited diabetic nephropathy; two (13%, diabetic retinopathy and three (19%, peripheral neuropathy of lower legs. All patients achieved the target carbohydrate metabolism; the level of C-peptide was within the reference range. Conclusion. Four different subtypes of MODY (2, 3, 8, 12 were diagnosed in the present study, which differed in their clinical characteristics, presence of complications and treatment strategies. Our knowledge of monogenic forms of diabetes is expanding with the development in molecular genetics, but several aspects related to them require further study.

Multiscale simulations in face-centered cubic metals: A method coupling quantum mechanics and molecular mechanics

International Nuclear Information System (INIS)

Yu Xiao-Xiang; Wang Chong-Yu

2013-01-01

An effective multiscale simulation which concurrently couples the quantum-mechanical and molecular-mechanical calculations based on the position continuity of atoms is presented. By an iterative procedure, the structure of the dislocation core in face-centered cubic metal is obtained by first-principles calculation and the long-range stress is released by molecular dynamics relaxation. Compared to earlier multiscale methods, the present work couples the long-range strain to the local displacements of the dislocation core in a simpler way with the same accuracy. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Molecular genetic analysis of activation-tagged transcription factors thought to be involved in photomorphogenesis

Energy Technology Data Exchange (ETDEWEB)

Neff, Michael M.

2011-06-23

This is a final report for Department of Energy Grant No. DE-FG02-08ER15927 entitled “Molecular Genetic Analysis of Activation-Tagged Transcription Factors Thought to be Involved in Photomorphogenesis”. Based on our preliminary photobiological and genetic analysis of the sob1-D mutant, we hypothesized that OBP3 is a transcription factor involved in both phytochrome and cryptochrome-mediated signal transduction. In addition, we hypothesized that OBP3 is involved in auxin signaling and root development. Based on our preliminary photobiological and genetic analysis of the sob2-D mutant, we also hypothesized that a related gene, LEP, is involved in hormone signaling and seedling development.

Environmental chemical mutagens and genetic risks: Lessons from radiation genetics

International Nuclear Information System (INIS)

Sankaranarayanan, K.

1996-01-01

The last three decades have witnessed substantial progress in the development and use of a variety of in vitro and in vivo assay systems for the testing of environmental chemicals which may pose a mutagenic hazard to humans. This is also true of basic studies in chemical mutagenesis on mechanisms, DNA repair, molecular dosimetry, structure-activity relationships, etc. However, the field of quantitative evaluation of genetic risks of environmental chemicals to humans is still in it infancy. This commentary addresses the question of how our experience in estimating genetic risks of exposure to ionizing radiation can be helpful in similar endeavors with environmental chemical mutagens. 24 refs., 3 tabs

DMPD: Molecular mechanisms of the anti-inflammatory functions of interferons. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 18086388 Molecular mechanisms of the anti-inflammatory functions of interferons. Ko....csml) Show Molecular mechanisms of the anti-inflammatory functions of interferons. PubmedID 18086388 Title ...Molecular mechanisms of the anti-inflammatory functions of interferons. Authors K

["A decision meaning a new foundation...": from the Kaiser Wilhelm Institute for Anthropology, Human Genetics and Eugenics to the Max Planck Institute for Molecular Genetics].

Science.gov (United States)

Sachse, Carola

2011-01-01

The Max Planck Institute for Molecular Genetics (MPIMG) in Berlin-Dahlem dates its establishment to 1964. Its homepage makes no mention of its predecessor institutes, the Kaiser Wilhelm Institute for Anthropology, Human Genetics and Eugenics (KWIA) and the subsequent MPI for Comparative Genetics and Hereditary Pathology (MPIVEE). This article traces the two critical phases of transition regarding the constellations of academic staff, institutional and epistemic ruptures and continuities specific to the era. Only one of the five department heads from the final war years, Hans Nachtsheim, remained a researcher within the Max Planck Society (MPG); he nevertheless continued to advocate the pre-war and wartime eugenic agenda in the life sciences and social policy. The generational change of 1959/60 became a massive struggle within the institute, in which microbial genetics (with Fritz Kaudewitz) was pitted against human genetics (with Friedrich Vogel) and managed to establish itself after a fresh change in personnel in 1964/65. For the Dahlem institute, this involved a far-reaching reorientation of its research, but for the genetically oriented life sciences in the Max Planck Society as a whole it only meant that molecular biology, which was already being pursued in the West German institutes, gained an additional facility. With this realignment of research traditions, the Society was able to draw a line under the Nazi past without having to address it head-on.

New STS molecular markers for assessment of genetic diversity and DNA fingerprinting in hop (Humulus lupulus L.)

Czech Academy of Sciences Publication Activity Database

Patzak, J.; Vrba, Lukáš; Matoušek, Jaroslav

2007-01-01

Roč. 50, č. 1 (2007), s. 15-25 ISSN 0831-2796 R&D Projects: GA ČR GA521/03/0072 Institutional research plan: CEZ:AV0Z50510513 Keywords : hop (Humulus lupulus L.) * genetic diversity Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.785, year: 2007

Is pigment patterning in fish skin determined by the Turing mechanism?

Science.gov (United States)

Watanabe, Masakatsu; Kondo, Shigeru

2015-02-01

More than half a century ago, Alan Turing postulated that pigment patterns may arise from a mechanism that could be mathematically modeled based on the diffusion of two substances that interact with each other. Over the past 15 years, the molecular and genetic tools to verify this prediction have become available. Here, we review experimental studies aimed at identifying the mechanism underlying pigment pattern formation in zebrafish. Extensive molecular genetic studies in this model organism have revealed the interactions between the pigment cells that are responsible for the patterns. The mechanism discovered is substantially different from that predicted by the mathematical model, but it retains the property of 'local activation and long-range inhibition', a necessary condition for Turing pattern formation. Although some of the molecular details of pattern formation remain to be elucidated, current evidence confirms that the underlying mechanism is mathematically equivalent to the Turing mechanism. Copyright © 2014 Elsevier Ltd. All rights reserved.

Molecular mechanisms in radiation damage to DNA: Final report

International Nuclear Information System (INIS)

Osman, R.

1996-01-01

The objectives of this work were to elucidate the molecular mechanisms that were responsible for radiation-induced DNA damage. The studies were based on theoretical explorations of possible mechanisms that link initial radiation damage in the form of base and sugar damage to conformational changes in DNA

Molecular mechanisms controlling proton pumping by bacteriorhodopsin. Final report

Energy Technology Data Exchange (ETDEWEB)

Crouch, Rosalie K.; Ebrey, Thomas G.

2000-02-10

Bacteriorhodopsin (bR) is the simplest biological system for the transduction of light energy. Light energy is directly converted to transmembrane proton gradient by a single, small membrane protein. The extraordinary stability of bR makes it an outstanding subject for bioenergetic studies. This project has focused on the role of interactions between key residues of the pigment involved in light-induced proton transfer. Methods to estimate the strength of these interactions and their correlation with the rate and efficiency of proton transfer have been developed. The concept of the coupling of the protonation states of key groups has been applied to individual steps of the proton transfer with the ultimate goal of understanding on the molecular level the driving forces for proton transport and the pathway of the transported proton in bT. The mechanism of light-induced proton release, uptake and the mechanism of recovery of initial state of bT has been examined. The experiments were performed with genetically engineered, site-specific mutants of bR. This has enabled us to characterize the role of individual amino acid residues in bR. Time resolved and low temperature absorption spectroscopy and light-induced photocurrent measurements were used in order to study the photochemical cycle and proton transfer in mutant pigments. Chemical modification and crosslinking of both the specific amino acids to the chromophore or to other amino acids were used to elucidate the role of light-induced conformational changes in the photocycle and the structure of the protein in the ground state. The results of this project provided new knowledge on the architecture of the proton transfer pathways inside the protein, on the mechanism of proton release in bR, and on the role of specific amino acid residues in the structure and function of bR.

Molecular and cellular mechanisms of aldosterone producing adenoma development

Directory of Open Access Journals (Sweden)

Sheerazed eBoulkroun

2015-06-01

Full Text Available Primary aldosteronism (PA is the most common form of secondary hypertension with an estimated prevalence of ~10% in referred patients. PA occurs as a result of a dysregulation of the normal mechanisms controlling adrenal aldosterone production. It is characterized by hypertension with low plasma renin and elevated aldosterone and often associated with hypokalemia. The two major causes of PA are unilateral aldosterone producing adenoma (APA and bilateral adrenal hyperplasia, accounting together for ~95% of cases. In addition to the well-characterized effect of excess mineralocorticoids on blood pressure, high levels of aldosterone also have cardiovascular, renal and metabolic consequences. Hence, long-term consequences of PA include increased risk of coronary artery disease, myocardial infarction, heart failure and atrial fibrillation. Despite recent progress in the management of patients with PA, critical issues related to diagnosis, subtype differentiation and treatment of non-surgically correctable forms still persist. A better understanding of the pathogenic mechanisms of the disease should lead to the identification of more reliable diagnostic and prognostic biomarkers for a more sensitive and specific screening and new therapeutic options. In this review we will summarize our current knowledge on the molecular and cellular mechanisms of APA development. On one hand, we will discuss how various animal models have improved our understanding of the pathophysiology of excess aldosterone production. On the other hand, we will summarize the major advances made during the last few years in the genetics of APA due to transcriptomic studies and whole exome sequencing. The identification of recurrent and somatic mutations in genes coding for ion channels (KCNJ5 and CACNA1D and ATPases (ATP1A1 and ATP2B3 allowed highlighting the central role of calcium signaling in autonomous aldosterone production by the adrenal.

Identification of single-copy orthologous genes between Physalis and Solanum lycopersicum and analysis of genetic diversity in Physalis using molecular markers.

Science.gov (United States)

Wei, Jingli; Hu, Xiaorong; Yang, Jingjing; Yang, Wencai

2012-01-01

The genus Physalis includes a number of commercially important edible and ornamental species. Its high nutritional value and potential medicinal properties leads to the increased commercial interest in the products of this genus worldwide. However, lack of molecular markers prevents the detailed study of genetics and phylogeny in Physalis, which limits the progress of breeding. In the present study, we compared the DNA sequences between Physalis and tomato, and attempted to analyze genetic diversity in Physalis using tomato markers. Blasting 23180 DNA sequences derived from Physalis against the International Tomato Annotation Group (ITAG) Release2.3 Predicted CDS (SL2.40) discovered 3356 single-copy orthologous genes between them. A total of 38 accessions from at least six species of Physalis were subjected to genetic diversity analysis using 97 tomato markers and 25 SSR markers derived from P. peruviana. Majority (73.2%) of tomato markers could amplify DNA fragments from at least one accession of Physalis. Diversity in Physalis at molecular level was also detected. The average Nei's genetic distance between accessions was 0.3806 with a range of 0.2865 to 0.7091. These results indicated Physalis and tomato had similarity at both molecular marker and DNA sequence levels. Therefore, the molecular markers developed in tomato can be used in genetic study in Physalis.

Submillisecond Elastic Recoil Reveals Molecular Origins of Fibrin Fiber Mechanics

Science.gov (United States)

Hudson, Nathan E.; Ding, Feng; Bucay, Igal; O’Brien, E. Timothy; Gorkun, Oleg V.; Superfine, Richard; Lord, Susan T.; Dokholyan, Nikolay V.; Falvo, Michael R.

2013-01-01

Fibrin fibers form the structural scaffold of blood clots. Thus, their mechanical properties are of central importance to understanding hemostasis and thrombotic disease. Recent studies have revealed that fibrin fibers are elastomeric despite their high degree of molecular ordering. These results have inspired a variety of molecular models for fibrin’s elasticity, ranging from reversible protein unfolding to rubber-like elasticity. An important property that has not been explored is the timescale of elastic recoil, a parameter that is critical for fibrin’s mechanical function and places a temporal constraint on molecular models of fiber elasticity. Using high-frame-rate imaging and atomic force microscopy-based nanomanipulation, we measured the recoil dynamics of individual fibrin fibers and found that the recoil was orders of magnitude faster than anticipated from models involving protein refolding. We also performed steered discrete molecular-dynamics simulations to investigate the molecular origins of the observed recoil. Our results point to the unstructured αC regions of the otherwise structured fibrin molecule as being responsible for the elastic recoil of the fibers. PMID:23790375

Population genetic structure of rare and endangered plants using molecular markers

Science.gov (United States)

Raji, Jennifer; Atkinson, Carter T.

2013-01-01

This study was initiated to assess the levels of genetic diversity and differentiation in the remaining populations of Phyllostegia stachyoides and Melicope zahlbruckneri in Hawai`i Volcanoes National Park and determine the extent of gene flow to identify genetically distinct individuals or groups for conservation purposes. Thirty-six Amplified Fragment Length Polymorphic (AFLP) primer combinations generated a total of 3,242 polymorphic deoxyribonucleic acid (DNA) fragments in the P. stachyoides population with a percentage of polymorphic bands (PPB) ranging from 39.3 to 65.7% and 2,780 for the M. zahlbruckneri population with a PPB of 18.8 to 64.6%. Population differentiation (Fst) of AFLP loci between subpopulations of P. stachyoides was low (0.043) across populations. Analysis of molecular variance of P. stachyoides showed that 4% of the observed genetic differentiation occurred between populations in different kīpuka and 96% when individuals were pooled from all kīpuka. Moderate genetic diversity was detected within the M. zahlbruckneri population. Bayesian and multivariate analyses both classified the P. stachyoides and M. zahlbruckneri populations into genetic groups with considerable sub-structuring detected in the P. stachyoides population. The proportion of genetic differentiation among populations explained by geographical distance was estimated by Mantel tests. No spatial correlation was found between genetic and geographic distances in both populations. Finally, a moderate but significant gene flow that could be attributed to insect or bird-mediated dispersal of pollen across the different kīpuka was observed. The results of this study highlight the utility of a multi-allelic DNA-based marker in screening a large number of polymorphic loci in small and closely related endangered populations and revealed the presence of genetically unique groups of individuals in both M. zahlbruckneri and P. stachyoides populations. Based on these findings

Molecular Genetics and Gene Therapy in Esophageal Cancer: a Review Article

Directory of Open Access Journals (Sweden)

Mohammad Reza Noori Daloii Ph.D.

2011-06-01

Full Text Available Background: With approximately 386,000 deaths per year, esophageal cancer is the 6th most common cause of death due to cancer in the world. This cancer, like any other cancer, is the outcome of genetic alterations or environmental factors such as tobacco smoke and gastro-esophageal reflux. Tobacco smoking is a major etiologic factor for esophageal squamous cell carcinoma in western countries, and it increases the risk by approximately 3 to 5 folds. Chronic gastro-esophageal reflux usually leads to the replacement of squamous mucosa by intestinal-type Barrett’s metaplastic mucosa which is considered the most important factor causing esophageal adenocarcinoma. In contrast to esophageal adenocarcinoma, different risk factors and mechanisms, such as mutations in oncogenes and tumor suppressor genes, play an important role in causing esophageal squamous cell carcinoma. Molecular studies on esophageal cancers have revealed frequent genetic abnormalities in esophageal squamous cell carcinoma and adenocarcinoma, including altered expression of p53, p16, cyclin D1, EGFR, E-cadherin, COX-2, iNOS, RARs, Rb, hTERT, p21, APC, c-MYC, VEGF, TGT-α and NF-κB. Many studies have focused on the role of different polymorphisms such as aldehyde dehydrogenase 2 and alcohol dehydrogenase 2 in causing esophageal cancer. Different agents including bestatin, curcumin, black raspberries, 5-lipoxygenase (LOX and COX-2 inhibitors have been found to play a role in inhibiting esophageal carcinogenesis. Different gene therapy approaches including p53 and p21WAF1 replacement gene therapies and therapy by suicide genes have also been experimented. Moreover, efforts have been made to use nanotechnology and aptamer technology in this regard.

Changes in cytogenetics and molecular genetics in acute myeloid leukemia from childhood to adult age groups.

Science.gov (United States)

Creutzig, Ursula; Zimmermann, Martin; Reinhardt, Dirk; Rasche, Mareike; von Neuhoff, Christine; Alpermann, Tamara; Dworzak, Michael; Perglerová, Karolína; Zemanova, Zuzana; Tchinda, Joelle; Bradtke, Jutta; Thiede, Christian; Haferlach, Claudia

2016-12-15

To obtain better insight into the biology of acute myeloid leukemia (AML) in various age groups, this study focused on the genetic changes occurring during a lifetime. This study analyzed the relation between age and genetics from birth to 100 years in 5564 patients with de novo AML diagnosed from 1998 to 2012 (1192 patients from nationwide pediatric studies [AML Berlin-Frankfurt-Münster studies 98 and 2004] and 4372 adults registered with the Munich Leukemia Laboratory). The frequencies of cytogenetic subgroups were age-dependent. Favorable subtypes (t(8;21), inv(16)/t(16;16), and t(15;17)) decreased in general from the pediatric age group (2 to groups ( 70 years; P age-specific incidence with age. Interestingly, the frequency of 11q23 abnormalities decreased from infants to older patients. The proportion of clinically relevant molecular aberrations of CCAAT/enhancer binding protein α, nucleophosmin (NPM1), and NPM1/fms-related tyrosine kinase 3-internal tandem duplication increased with age. Altogether, with the exclusion of infants, a significant decrease in the proportion of favorable cytogenetic subtypes and an increase in unfavorable cytogenetics were observed with increasing age. These findings indicate different mechanisms for the pathogenesis of AML; these different mechanisms also suggest directions for etiological research and contribute to the more unfavorable prognosis with increasing age. Cancer 2016;122:3821-3830. © 2016 American Cancer Society. © 2016 American Cancer Society.

Introductory guide to the statistics of molecular genetics.

Science.gov (United States)

Eley, Thalia C; Rijsdijk, Frühling

2005-10-01

This introductory guide presents the main two analytical approaches used by molecular geneticists: linkage and association. Traditional linkage and association methods are described, along with more recent advances in methodologies such as those using a variance components approach. New methods are being developed all the time but the core principles of linkage and association remain the same. The basis of linkage is the transmission of a marker along with a disease within families, whereas association is based on the comparison of marker frequencies in case and control groups. It is becoming increasingly clear that effect sizes of individual markers on diseases and traits are likely to be very small. As such, much greater power is needed, and correspondingly greater sample sizes. Although non-replication is still a problem, molecular genetic studies in some areas such as attention deficit/hyperactivity disorder (ADHD) are starting to show greater convergence. Epidemiologists and other researchers with large well-characterized samples will be well placed to use these methods. Inter-disciplinary studies can then ask far more interesting questions such as those relating to developmental, multivariate and gene-environment interaction hypotheses.

Molecular mechanisms of cisplatin resistance in cervical cancer

Directory of Open Access Journals (Sweden)

Zhu H

2016-06-01

Full Text Available Haiyan Zhu, Hui Luo, Wenwen Zhang, Zhaojun Shen, Xiaoli Hu, Xueqiong Zhu Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, People’s Republic of China Abstract: Patients with advanced or recurrent cervical cancer have poor prognosis, and their 1-year survival is only 10%–20%. Chemotherapy is considered as the standard treatment for patients with advanced or recurrent cervical cancer, and cisplatin appears to treat the disease effectively. However, resistance to cisplatin may develop, thus substantially compromising the efficacy of cisplatin to treat advanced or recurrent cervical cancer. In this article, we systematically review the recent literature and summarize the recent advances in our understanding of the molecular mechanisms underlying cisplatin resistance in cervical cancer. Keywords: cisplatin, epithelial–mesenchymal transition, microRNA, molecular mechanism, resistance

Combined quantum and molecular mechanics (QM/MM).

Science.gov (United States)

Friesner, Richard A

2004-12-01

We describe the current state of the art of mixed quantum mechanics/molecular mechanics (QM/MM) methodology, with a particular focus on modeling of enzymatic reactions. Over the past decade, the effectiveness of these methods has increased dramatically, based on improved quantum chemical methods, advances in the description of the QM/MM interface, and reductions in the cost/performance of computing hardware. Two examples of pharmaceutically relevant applications, cytochrome P450 and class C β-lactamase, are presented.: © 2004 Elsevier Ltd . All rights reserved.

The Genetics of Canine Skull Shape Variation

Science.gov (United States)

Schoenebeck, Jeffrey J.; Ostrander, Elaine A.

2013-01-01

A dog’s craniofacial diversity is the result of continual human intervention in natural selection, a process that began tens of thousands of years ago. To date, we know little of the genetic underpinnings and developmental mechanisms that make dog skulls so morphologically plastic. In this Perspectives, we discuss the origins of dog skull shapes in terms of history and biology and highlight recent advances in understanding the genetics of canine skull shapes. Of particular interest are those molecular genetic changes that are associated with the development of distinct breeds. PMID:23396475

Intestinal Insulin Signaling Encodes Two Different Molecular Mechanisms for the Shortened Longevity Induced by Graphene Oxide in Caenorhabditis elegans

Science.gov (United States)

Zhao, Yunli; Yang, Ruilong; Rui, Qi; Wang, Dayong

2016-04-01

Graphene oxide (GO) has been shown to cause multiple toxicities in various organisms. However, the underlying molecular mechanisms for GO-induced shortened longevity are still unclear. We employed Caenorhabditis elegans to investigate the possible involvement of insulin signaling pathway in the control of GO toxicity and its underlying molecular mechanisms. Mutation of daf-2, age-1, akt-1, or akt-2 gene induced a resistant property of nematodes to GO toxicity, while mutation of daf-16 gene led to a susceptible property of nematodes to GO toxicity, suggesting that GO may dysregulate the functions of DAF-2/IGF-1 receptor, AGE-1, AKT-1 and AKT-2-mediated kinase cascade, and DAF-16/FOXO transcription factor. Genetic interaction analysis suggested the involvement of signaling cascade of DAF-2-AGE-1-AKT-1/2-DAF-16 in the control of GO toxicity on longevity. Moreover, intestinal RNA interference (RNAi) analysis demonstrated that GO reduced longevity by affecting the functions of signaling cascade of DAF-2-AGE-1-AKT-1/2-DAF-16 in the intestine. DAF-16 could also regulate GO toxicity on longevity by functioning upstream of SOD-3, which encodes an antioxidation system that prevents the accumulation of oxidative stress. Therefore, intestinal insulin signaling may encode two different molecular mechanisms responsible for the GO toxicity in inducing the shortened longevity. Our results highlight the key role of insulin signaling pathway in the control of GO toxicity in organisms.

Molecular technology and antigenic variation among intraerythrocytic hemoparasites: do we see reality?

Science.gov (United States)

Allred, D R

2001-11-22

Antigenic variation is one mechanism of immune evasion utilized by many microorganisms--encompassing such broad evolutionary groups as viruses, bacteria, and protozoa--to survive the onslaught of a specifically activated host immune system. Because of its importance to the survival of many infectious agents there is considerable interest in understanding this phenomenon. With knowledge of the molecular mechanisms by which these microbes deliberately manipulate their genomes, it may be possible to disrupt the molecular machinery of the responsible genetic mechanisms. Among intraerythrocytic parasites, genetic mechanisms that have been observed or postulated to control antigenic variation include segmental gene conversion, epigenetically controlled in situ transcriptional switching, alterations of chromosomal structure associated with transcriptional control, and recombination during sexual reproduction. Likely, more than one type of mechanism is used by all organisms that undergo antigenic variation. In this paper, both the observed mechanisms and some of the molecular technology used to detect these mechanisms are discussed. While often seemingly straightforward from a technical standpoint, sometimes subtle differences in the methods used to study this process may affect what is observed. Some examples of this phenomenon are discussed in the context of a small selection of intraerythrocytic parasites.

Molecular epidemiology and evolutionary genetics of Mycobacterium tuberculosis in Taipei

OpenAIRE

Su Ih-Jen; Lee Shi-Yi; Tsai Wen-Shing; Sun Jun-Ren; Chang Jia-Ru; Lin Chih-Wei; Tseng Fan-Chen; Dou Horng-Yunn; Lu Jang-Jih

2008-01-01

Abstract Background The control of tuberculosis in densely populated cities is complicated by close human-to-human contacts and potential transmission of pathogens from multiple sources. We conducted a molecular epidemiologic analysis of 356 Mycobacterium tuberculosis (MTB) isolates from patients presenting pulmonary tuberculosis in metropolitan Taipei. Classical antibiogram studies and genetic characterization, using mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (M...

Avoiding pitfalls in molecular genetic testing: case studies of high-resolution array comparative genomic hybridization testing in the definitive diagnosis of Mowat-Wilson syndrome.

Science.gov (United States)

Kluk, Michael Joseph; An, Yu; James, Philip; Coulter, David; Harris, David; Wu, Bai-Lin; Shen, Yiping

2011-05-01

The molecular testing options available for the diagnosis of genetic disorders are numerous and include a variety of different assay platforms. The consultative input of molecular pathologists and cytogeneticists, working closely with the ordering clinicians, is often important for definitive diagnosis. Herein, we describe two patients who had long histories of unexplained signs and symptoms with a high clinical suspicion of an underlying genetic etiology. Initial molecular testing in both cases was negative, but the application of high-resolution array comparative genomic hybridization technology lead to definitive diagnosis in both cases. We summarize the clinical findings and molecular testing in each case, discuss the differential diagnoses, and review the clinical and pathological findings of Mowat-Wilson syndrome. This report highlights the importance for those involved in molecular testing to know the nature of the underlying genetic abnormalities associated with the suspected diagnosis, to recognize the limitations of each testing platform, and to persistently pursue repeat testing using high-resolution technologies when indicated. This concept is applicable to both germline and somatic molecular genetic testing. Copyright © 2011 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

[Noonan syndrome can be diagnosed clinically and through molecular genetic analyses].

Science.gov (United States)

Henningsen, Marie Krab; Jelsig, Anne Marie; Andersen, Helle; Brusgaard, Klaus; Ousager, Lilian Bomme; Hertz, Jens Michael

2015-08-03

Noonan syndrome is part of the group of RASopathies caused by germ line mutations in genes involved in the RAS/MAPK pathway. There is substantial phenotypic overlap among the RASopathies. Diagnosis of Noonan syndrome is often based on clinical features including dysmorphic facial features, short stature and congenital heart disease. Rapid advances in sequencing technology have made molecular genetic analyses a helpful tool in diagnosing and distinguishing Noonan syndrome from other RASopathies.

Optimization and benchmarking of a perturbative Metropolis Monte Carlo quantum mechanics/molecular mechanics program.

Science.gov (United States)

Feldt, Jonas; Miranda, Sebastião; Pratas, Frederico; Roma, Nuno; Tomás, Pedro; Mata, Ricardo A

2017-12-28

In this work, we present an optimized perturbative quantum mechanics/molecular mechanics (QM/MM) method for use in Metropolis Monte Carlo simulations. The model adopted is particularly tailored for the simulation of molecular systems in solution but can be readily extended to other applications, such as catalysis in enzymatic environments. The electrostatic coupling between the QM and MM systems is simplified by applying perturbation theory to estimate the energy changes caused by a movement in the MM system. This approximation, together with the effective use of GPU acceleration, leads to a negligible added computational cost for the sampling of the environment. Benchmark calculations are carried out to evaluate the impact of the approximations applied and the overall computational performance.

Molecular genetic diversity of Punica granatum L. (pomegranate) as revealed by microsatellite DNA markers

Science.gov (United States)

Pomegranate (Punica granatum L.) is one of the oldest known edible fruits and more and more it arouse interest of scientific community given its numerous biological activities. However, information about its genetic resources and characterization using reliable molecular markers are still scarce. In...

Study of inter species diversity and population structure by molecular genetic method in Iranian Artemia

OpenAIRE

Hajirostamloo, Mahbobeh

2005-01-01

Artemia is a small crustacean that adapted to live in brine water and has been seen in different brine water sources in Iran. Considering the importance of genetic studies manifest inter population differences in species, to estimate genetic structure, detect difference at molecular level and separate different Artemia populations of Iran, also study of phylogenic relationships among them, samples of Artemia were collected from nine region: Urmia lake in West Azerbaijan, Sh...

Molecular genetic features of polyploidization and aneuploidization reveal unique patterns for genome duplication in diploid Malus.

Directory of Open Access Journals (Sweden)

Michael J Considine

Full Text Available Polyploidization results in genome duplication and is an important step in evolution and speciation. The Malus genome confirmed that this genus was derived through auto-polyploidization, yet the genetic and meiotic mechanisms for polyploidization, particularly for aneuploidization, are unclear in this genus or other woody perennials. In fact the contribution of aneuploidization remains poorly understood throughout Plantae. We add to this knowledge by characterization of eupolyploidization and aneuploidization in 27,542 F₁ seedlings from seven diploid Malus populations using cytology and microsatellite markers. We provide the first evidence that aneuploidy exceeds eupolyploidy in the diploid crosses, suggesting aneuploidization is a leading cause of genome duplication. Gametes from diploid Malus had a unique combinational pattern; ova preserved euploidy exclusively, while spermatozoa presented both euploidy and aneuploidy. All non-reduced gametes were genetically heterozygous, indicating first-division restitution was the exclusive mode for Malus eupolyploidization and aneuploidization. Chromosome segregation pattern among aneuploids was non-uniform, however, certain chromosomes were associated for aneuploidization. This study is the first to provide molecular evidence for the contribution of heterozygous non-reduced gametes to fitness in polyploids and aneuploids. Aneuploidization can increase, while eupolyploidization may decrease genetic diversity in their newly established populations. Auto-triploidization is important for speciation in the extant Malus. The features of Malus polyploidization confer genetic stability and diversity, and present heterozygosity, heterosis and adaptability for evolutionary selection. A protocol using co-dominant markers was proposed for accelerating apple triploid breeding program. A path was postulated for evolution of numerically odd basic chromosomes. The model for Malus derivation was considerably revised

Molecular genetic features of polyploidization and aneuploidization reveal unique patterns for genome duplication in diploid Malus.

Science.gov (United States)

Considine, Michael J; Wan, Yizhen; D'Antuono, Mario F; Zhou, Qian; Han, Mingyu; Gao, Hua; Wang, Man

2012-01-01

Polyploidization results in genome duplication and is an important step in evolution and speciation. The Malus genome confirmed that this genus was derived through auto-polyploidization, yet the genetic and meiotic mechanisms for polyploidization, particularly for aneuploidization, are unclear in this genus or other woody perennials. In fact the contribution of aneuploidization remains poorly understood throughout Plantae. We add to this knowledge by characterization of eupolyploidization and aneuploidization in 27,542 F₁ seedlings from seven diploid Malus populations using cytology and microsatellite markers. We provide the first evidence that aneuploidy exceeds eupolyploidy in the diploid crosses, suggesting aneuploidization is a leading cause of genome duplication. Gametes from diploid Malus had a unique combinational pattern; ova preserved euploidy exclusively, while spermatozoa presented both euploidy and aneuploidy. All non-reduced gametes were genetically heterozygous, indicating first-division restitution was the exclusive mode for Malus eupolyploidization and aneuploidization. Chromosome segregation pattern among aneuploids was non-uniform, however, certain chromosomes were associated for aneuploidization. This study is the first to provide molecular evidence for the contribution of heterozygous non-reduced gametes to fitness in polyploids and aneuploids. Aneuploidization can increase, while eupolyploidization may decrease genetic diversity in their newly established populations. Auto-triploidization is important for speciation in the extant Malus. The features of Malus polyploidization confer genetic stability and diversity, and present heterozygosity, heterosis and adaptability for evolutionary selection. A protocol using co-dominant markers was proposed for accelerating apple triploid breeding program. A path was postulated for evolution of numerically odd basic chromosomes. The model for Malus derivation was considerably revised. Impacts of

Adaptive divergence despite strong genetic drift: genomic analysis of the evolutionary mechanisms causing genetic differentiation in the island fox (Urocyon littoralis)

Science.gov (United States)

FUNK, W. CHRIS; LOVICH, ROBERT E.; HOHENLOHE, PAUL A.; HOFMAN, COURTNEY A.; MORRISON, SCOTT A.; SILLETT, T. SCOTT; GHALAMBOR, CAMERON K.; MALDONADO, JESUS E.; RICK, TORBEN C.; DAY, MITCH D.; POLATO, NICHOLAS R.; FITZPATRICK, SARAH W.; COONAN, TIMOTHY J.; CROOKS, KEVIN R.; DILLON, ADAM; GARCELON, DAVID K.; KING, JULIE L.; BOSER, CHRISTINA L.; GOULD, NICHOLAS; ANDELT, WILLIAM F.

2016-01-01

The evolutionary mechanisms generating the tremendous biodiversity of islands have long fascinated evolutionary biologists. Genetic drift and divergent selection are predicted to be strong on islands and both could drive population divergence and speciation. Alternatively, strong genetic drift may preclude adaptation. We conducted a genomic analysis to test the roles of genetic drift and divergent selection in causing genetic differentiation among populations of the island fox (Urocyon littoralis). This species consists of 6 subspecies, each of which occupies a different California Channel Island. Analysis of 5293 SNP loci generated using Restriction-site Associated DNA (RAD) sequencing found support for genetic drift as the dominant evolutionary mechanism driving population divergence among island fox populations. In particular, populations had exceptionally low genetic variation, small Ne (range = 2.1–89.7; median = 19.4), and significant genetic signatures of bottlenecks. Moreover, islands with the lowest genetic variation (and, by inference, the strongest historical genetic drift) were most genetically differentiated from mainland gray foxes, and vice versa, indicating genetic drift drives genome-wide divergence. Nonetheless, outlier tests identified 3.6–6.6% of loci as high FST outliers, suggesting that despite strong genetic drift, divergent selection contributes to population divergence. Patterns of similarity among populations based on high FST outliers mirrored patterns based on morphology, providing additional evidence that outliers reflect adaptive divergence. Extremely low genetic variation and small Ne in some island fox populations, particularly on San Nicolas Island, suggest that they may be vulnerable to fixation of deleterious alleles, decreased fitness, and reduced adaptive potential. PMID:26992010

Adaptive divergence despite strong genetic drift: genomic analysis of the evolutionary mechanisms causing genetic differentiation in the island fox (Urocyon littoralis).

Science.gov (United States)

Funk, W Chris; Lovich, Robert E; Hohenlohe, Paul A; Hofman, Courtney A; Morrison, Scott A; Sillett, T Scott; Ghalambor, Cameron K; Maldonado, Jesus E; Rick, Torben C; Day, Mitch D; Polato, Nicholas R; Fitzpatrick, Sarah W; Coonan, Timothy J; Crooks, Kevin R; Dillon, Adam; Garcelon, David K; King, Julie L; Boser, Christina L; Gould, Nicholas; Andelt, William F

2016-05-01

The evolutionary mechanisms generating the tremendous biodiversity of islands have long fascinated evolutionary biologists. Genetic drift and divergent selection are predicted to be strong on islands and both could drive population divergence and speciation. Alternatively, strong genetic drift may preclude adaptation. We conducted a genomic analysis to test the roles of genetic drift and divergent selection in causing genetic differentiation among populations of the island fox (Urocyon littoralis). This species consists of six subspecies, each of which occupies a different California Channel Island. Analysis of 5293 SNP loci generated using Restriction-site Associated DNA (RAD) sequencing found support for genetic drift as the dominant evolutionary mechanism driving population divergence among island fox populations. In particular, populations had exceptionally low genetic variation, small Ne (range = 2.1-89.7; median = 19.4), and significant genetic signatures of bottlenecks. Moreover, islands with the lowest genetic variation (and, by inference, the strongest historical genetic drift) were most genetically differentiated from mainland grey foxes, and vice versa, indicating genetic drift drives genome-wide divergence. Nonetheless, outlier tests identified 3.6-6.6% of loci as high FST outliers, suggesting that despite strong genetic drift, divergent selection contributes to population divergence. Patterns of similarity among populations based on high FST outliers mirrored patterns based on morphology, providing additional evidence that outliers reflect adaptive divergence. Extremely low genetic variation and small Ne in some island fox populations, particularly on San Nicolas Island, suggest that they may be vulnerable to fixation of deleterious alleles, decreased fitness and reduced adaptive potential. © 2016 John Wiley & Sons Ltd.

Molecular mechanism of Danshensu on platelet antiaggregation

Science.gov (United States)

Yu, Chen; Geng, Feng; Fan, Hua-Ying; Luan, Hai-Yun; Liu, Yue; Ji, Kai; Fu, Feng-Hua

2018-04-01

In this study, we detected the effect of Danshensu on PARs-PLCβsignaling pathway to elucidate molecular mechanism of Danshensu on platelet anti-aggregation. Our results demonstrate that Danshensu is able to decrease the levels of IP3, Ca2+ and AA secretion, which indicate that Danshensu may involve in PARs-PLCβ signaling pathways. Molecular docking study shows that Danshesu has similar polar interactions with PAR1 receptors as BMS200261 at the same position. The findings from our study enable a better understanding of Danshensu biological properties, which could ultimately lead to the development of multi-target antiplatelet natural medicine for the treatment and/or prevention of some thrombotic diseases.

Evaluation of carbohydrate molecular mechanical force fields by quantum mechanical calculations

DEFF Research Database (Denmark)

Hemmingsen, Lars Bo Stegeager; Madsen, D.E.; Esbensen, A.L.

2004-01-01

of the (gg, gt and tg) rotamers of methyl alpha-D-glucopyranoside and methyl alpha-D-galactopyranoside are (0.13, 0.00, 0.15) and (0.64, 0.00, 0.77) kcal/mol. respectively. The results of the quantum mechanical calculations are compared with the results of calculations using the 20 second...... for monosaccharide carbohydrate benchmark systems. Selected results are: (i) The interaction energy of the alpha-D-alucopyranose-H2O heterodimer is estimated to be 4.9 kcal/mol, using a composite method including terms at highly correlated (CCSD(T)) level. Most molecular mechanics force fields are in error...

A Model of How Different Biology Experts Explain Molecular and Cellular Mechanisms

Science.gov (United States)

Trujillo, Caleb M.; Anderson, Trevor R.; Pelaez, Nancy J.

2015-01-01

Constructing explanations is an essential skill for all science learners. The goal of this project was to model the key components of expert explanation of molecular and cellular mechanisms. As such, we asked: What is an appropriate model of the components of explanation used by biology experts to explain molecular and cellular mechanisms? Do…

Implication of Gastric Cancer Molecular Genetic Markers in Surgical Practice.

Science.gov (United States)

Nemtsova, Marina V; Strelnikov, Vladimir V; Tanas, Alexander S; Bykov, Igor I; Zaletaev, Dmitry V; Rudenko, Viktoria V; Glukhov, Alexander I; Kchorobrich, Tatiana V; Li, Yi; Tarasov, Vadim V; Barreto, George E; Aliev, Gjumrakch

2017-10-01

We have investigated aberrant methylation of genes CDH1, RASSF1A, MLH1, N33, DAPK, expression of genes hTERT, MMP7, MMP9, BIRC5 (survivin), PTGS2, and activity of telomerase of 106 gastric tumor samples obtained intra-operatively and 53 gastric tumor samples from the same group of patients obtained endoscopically before surgery. Biopsy specimens obtained from 50 patients with chronic calculous cholecystitis were used as a control group. Together with tissue samples obtained from different sites remote to tumors, a total of 727 samples have been studied. The selected parameters comprise a system of molecular markers that can be used in both diagnostics of gastric cancer and in dynamic monitoring of patients after surgery. Special attention was paid to the use of molecular markers for the diagnostics of malignant process in the material obtained endoscopically since the efficacy of morphological diagnostics in biopsies is compromised by intratumoral heterogeneity, which may prevent reliable identification of tumor cells in the sampling. Our data indicated that certain molecular genetic events provided more sensitive yet specific markers of the tumor. We demonstrated that molecular profiles detected in preoperative biopsies were confirmed by the material obtained intra-operatively. The use of endoscopic material facilitates gastric tumors pre-operative diagnostics, improving early detection of gastric cancer and potential effective treatment strategies.

[Molecular Biology on the Mechanisms of Autism Spectrum Disorder for Clinical Psychiatrists].

Science.gov (United States)

Makinodan, Manabu

2015-01-01

While, in general, a certain number of clinical psychiatrists might not be familiar with molecular biology, the mechanisms of mental illnesses have been uncovered by molecular biology for decades. Among mental illnesses, even biological psychiatrists and neuroscientists have paid less attention to the biological treatment of autism spectrum disorder (ASD) than Alzheimer's disease and schizophrenia since ASD has been regarded as a developmental disorder that was seemingly untreatable. However, multifaceted methods of molecular biology have revealed the mechanisms that would lead to the medication of ASD. In this article, how molecular biology dissects the pathobiology of ASD is described in order to announce the possibilities of biological treatment for clinical psychiatrists.

Genetic effects on gene expression across human tissues

NARCIS (Netherlands)

Battle, Alexis; Brown, Christopher D.; Engelhardt, Barbara E.; Montgomery, Stephen B.; Aguet, François; Ardlie, Kristin G.; Cummings, Beryl B.; Gelfand, Ellen T.; Getz, Gad; Hadley, Kane; Handsaker, Robert E.; Huang, Katherine H.; Kashin, Seva; Karczewski, Konrad J.; Lek, Monkol; Li, Xiao; MacArthur, Daniel G.; Nedzel, Jared L.; Nguyen, Duyen T.; Noble, Michael S.; Segrè, Ayellet V.; Trowbridge, Casandra A.; Tukiainen, Taru; Abell, Nathan S.; Balliu, Brunilda; Barshir, Ruth; Basha, Omer; Bogu, Gireesh K.; Brown, Andrew; Castel, Stephane E.; Chen, Lin S.; Chiang, Colby; Conrad, Donald F.; Cox, Nancy J.; Damani, Farhan N.; Davis, Joe R.; Delaneau, Olivier; Dermitzakis, Emmanouil T.; Eskin, Eleazar; Ferreira, Pedro G.; Frésard, Laure; Gamazon, Eric R.; Garrido-Martín, Diego; Gewirtz, Ariel D. H.; Gliner, Genna; Gloudemans, Michael J.; Guigo, Roderic; Hall, Ira M.; Han, Buhm; He, Yuan

2017-01-01

Characterization of the molecular function of the human genome and its variation across individuals is essential for identifying the cellular mechanisms that underlie human genetic traits and diseases. The Genotype-Tissue Expression (GTEx) project aims to characterize variation in gene expression

Molecular, metabolic, and genetic control: An introduction

Science.gov (United States)

Tyson, John J.; Mackey, Michael C.

2001-03-01

The living cell is a miniature, self-reproducing, biochemical machine. Like all machines, it has a power supply, a set of working components that carry out its necessary tasks, and control systems that ensure the proper coordination of these tasks. In this Special Issue, we focus on the molecular regulatory systems that control cell metabolism, gene expression, environmental responses, development, and reproduction. As for the control systems in human-engineered machines, these regulatory networks can be described by nonlinear dynamical equations, for example, ordinary differential equations, reaction-diffusion equations, stochastic differential equations, or cellular automata. The articles collected here illustrate (i) a range of theoretical problems presented by modern concepts of cellular regulation, (ii) some strategies for converting molecular mechanisms into dynamical systems, (iii) some useful mathematical tools for analyzing and simulating these systems, and (iv) the sort of results that derive from serious interplay between theory and experiment.

Building muscle: molecular regulation of myogenesis.

Science.gov (United States)

Bentzinger, C Florian; Wang, Yu Xin; Rudnicki, Michael A

2012-02-01

The genesis of skeletal muscle during embryonic development and postnatal life serves as a paradigm for stem and progenitor cell maintenance, lineage specification, and terminal differentiation. An elaborate interplay of extrinsic and intrinsic regulatory mechanisms controls myogenesis at all stages of development. Many aspects of adult myogenesis resemble or reiterate embryonic morphogenetic episodes, and related signaling mechanisms control the genetic networks that determine cell fate during these processes. An integrative view of all aspects of myogenesis is imperative for a comprehensive understanding of muscle formation. This article provides a holistic overview of the different stages and modes of myogenesis with an emphasis on the underlying signals, molecular switches, and genetic networks.

Identification of single-copy orthologous genes between Physalis and Solanum lycopersicum and analysis of genetic diversity in Physalis using molecular markers.

Directory of Open Access Journals (Sweden)

Jingli Wei

Full Text Available The genus Physalis includes a number of commercially important edible and ornamental species. Its high nutritional value and potential medicinal properties leads to the increased commercial interest in the products of this genus worldwide. However, lack of molecular markers prevents the detailed study of genetics and phylogeny in Physalis, which limits the progress of breeding. In the present study, we compared the DNA sequences between Physalis and tomato, and attempted to analyze genetic diversity in Physalis using tomato markers. Blasting 23180 DNA sequences derived from Physalis against the International Tomato Annotation Group (ITAG Release2.3 Predicted CDS (SL2.40 discovered 3356 single-copy orthologous genes between them. A total of 38 accessions from at least six species of Physalis were subjected to genetic diversity analysis using 97 tomato markers and 25 SSR markers derived from P. peruviana. Majority (73.2% of tomato markers could amplify DNA fragments from at least one accession of Physalis. Diversity in Physalis at molecular level was also detected. The average Nei's genetic distance between accessions was 0.3806 with a range of 0.2865 to 0.7091. These results indicated Physalis and tomato had similarity at both molecular marker and DNA sequence levels. Therefore, the molecular markers developed in tomato can be used in genetic study in Physalis.

Biochemical and molecular genetic studies on some cyanobacterial isolates

International Nuclear Information System (INIS)

Kamal, E.A.R.; Ebrahim, S.A.A.

2011-01-01

In the present study, the isolation and purification of a set of Cyanobacteria strains belonging to genus Oscillatoria was undertaken, followed by the analyses of phylogenetic relationships using different biochemical and molecular genetic techniques (SOS-PAGE and RAPO-PCR). A total of 45 protein bands were observed within the studied Osci/latoria isolates by SOS-PAGE (only three unique bands, eight monomorphic bands and 37 polymorphic bands). On the other hand, extracted ONA from isolates was used to identify the molecular fingerprints. A sum of 94 polymorphic bands was generated by these primers in the Ocsi/laloria genotypes under study. A total of 20 unique bands were identified out of the polymorphic ones. These unique bands were used to discriminate among the studied Ocsi/latoria isolates. Most isolates of Ocsi/latoria genotypes were discriminated by one or more unique bands. Numerical taxonomic using 45 protein attributes of 19 isolates and RAPO markers on five isolates. Two methods -Clustering (UPGMA) and Principal Component Analysis (PCA) were used for these analyses. The similarities and clusters produced between the studied isolates were discussed.

Biochemical and molecular genetic studies on some cyanobacterial isolates

Energy Technology Data Exchange (ETDEWEB)

Kamal, E A.R. [Umm Al-Qura University, Makkah (Saudi Arabia). Dept. of Biology; Ebrahim, S A.A. [Ain Sham University, Cairo (Egypt). Dept. of Cytogenetic

2011-11-15

In the present study, the isolation and purification of a set of Cyanobacteria strains belonging to genus Oscillatoria was undertaken, followed by the analyses of phylogenetic relationships using different biochemical and molecular genetic techniques (SOS-PAGE and RAPO-PCR). A total of 45 protein bands were observed within the studied Osci/latoria isolates by SOS-PAGE (only three unique bands, eight monomorphic bands and 37 polymorphic bands). On the other hand, extracted ONA from isolates was used to identify the molecular fingerprints. A sum of 94 polymorphic bands was generated by these primers in the Ocsi/laloria genotypes under study. A total of 20 unique bands were identified out of the polymorphic ones. These unique bands were used to discriminate among the studied Ocsi/latoria isolates. Most isolates of Ocsi/latoria genotypes were discriminated by one or more unique bands. Numerical taxonomic using 45 protein attributes of 19 isolates and RAPO markers on five isolates. Two methods -Clustering (UPGMA) and Principal Component Analysis (PCA) were used for these analyses. The similarities and clusters produced between the studied isolates were discussed.

Submillisecond elastic recoil reveals molecular origins of fibrin fiber mechanics.

Science.gov (United States)

Hudson, Nathan E; Ding, Feng; Bucay, Igal; O'Brien, E Timothy; Gorkun, Oleg V; Superfine, Richard; Lord, Susan T; Dokholyan, Nikolay V; Falvo, Michael R

2013-06-18

Fibrin fibers form the structural scaffold of blood clots. Thus, their mechanical properties are of central importance to understanding hemostasis and thrombotic disease. Recent studies have revealed that fibrin fibers are elastomeric despite their high degree of molecular ordering. These results have inspired a variety of molecular models for fibrin's elasticity, ranging from reversible protein unfolding to rubber-like elasticity. An important property that has not been explored is the timescale of elastic recoil, a parameter that is critical for fibrin's mechanical function and places a temporal constraint on molecular models of fiber elasticity. Using high-frame-rate imaging and atomic force microscopy-based nanomanipulation, we measured the recoil dynamics of individual fibrin fibers and found that the recoil was orders of magnitude faster than anticipated from models involving protein refolding. We also performed steered discrete molecular-dynamics simulations to investigate the molecular origins of the observed recoil. Our results point to the unstructured αC regions of the otherwise structured fibrin molecule as being responsible for the elastic recoil of the fibers. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Rare endocrine cancers have novel genetic alterations

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A molecular characterization of adrenocortical carcinoma, a rare cancer of the adrenal cortex, analyzed 91 cases for alterations in the tumor genomes and identified several novel genetic mutations as likely mechanisms driving the disease as well as whole genome doubling as a probable driver of the disease.

Scarlet Fever Upsurge in England and Molecular-Genetic Analysis in North-West London, 2014

Centers for Disease Control (CDC) Podcasts

2016-08-16

Sarah Gregory reads an abridged version of the article, Scarlet Fever Upsurge in England and Molecular-Genetic Analysis in North-West London, 2014.  Created: 8/16/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 8/16/2016.

Genetics of Schizophrenia: Historical Insights and Prevailing Evidence.

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van de Leemput, J; Hess, J L; Glatt, S J; Tsuang, M T

2016-01-01

Schizophrenia's (SZ's) heritability and familial transmission have been known for several decades; however, despite the clear evidence for a genetic component, it has been very difficult to pinpoint specific causative genes. Even so genetic studies have taught us a lot, even in the pregenomic era, about the molecular underpinnings and disease-relevant pathways. Recurring themes emerged revealing the involvement of neurodevelopmental processes, glutamate regulation, and immune system differential activation in SZ etiology. The recent emergence of epigenetic studies aimed at shedding light on the biological mechanisms underlying SZ has provided another layer of information in the investigation of gene and environment interactions. However, this epigenetic insight also brings forth another layer of complexity to the (epi)genomic landscape such as interactions between genetic variants, epigenetic marks-including cross-talk between DNA methylation and histone modification processes-, gene expression regulation, and environmental influences. In this review, we seek to synthesize perspectives, including limitations and obstacles yet to overcome, from genetic and epigenetic literature on SZ through a qualitative review of risk factors and prevailing hypotheses. Encouraged by the findings of both genetic and epigenetic studies to date, as well as the continued development of new technologies to collect and interpret large-scale studies, we are left with a positive outlook for the future of elucidating the molecular genetic mechanisms underlying SZ and other complex neuropsychiatric disorders. Copyright © 2016 Elsevier Inc. All rights reserved.

Genética, biologia molecular e ética: as relações trabalho e saúde Genetics, molecular biology and ethics: work and health connections

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Gilka Jorge Figaro Gattás

2002-01-01

Full Text Available O artigo discute o impacto dos avanços da genética e da biologia molecular sobre a prática em saúde ocupacional. O conhecimento atual sobre o genoma humano permite, em certas circunstâncias, identificar fatores individuais de suscetibilidade a doenças em situações de exposição a substâncias químicas ou físicas, ou ainda, a doenças genéticas de manifestação tardia. Estudos epidemiológicos incorporando elementos da genética e da biologia molecular têm sido desenhados para avaliar a interação de variantes metabólicas e exposições ambientais no risco de ocorrência de diferentes doenças. Apesar desta perspectiva, considera-se que as pesquisas nesta área são ainda incipientes. A estratégia para a redução dos danos causados à saúde do trabalhador deve continuar a ter como base, prioritariamente, a modificação e a adequação dos ambientes de trabalho e não a especificação genética da força de trabalho. Introduzir a discussão sobre a necessidade de definir princípios de responsabilidade social no uso de informações genéticas e que possam reger ações éticas em saúde do trabalhador é uma das propostas principais deste artigo.This paper provides a discussion about the increasing development of genetics and molecular biomarkers technologies and consequent impact on practices of occupational health. Genetic analysis could be in specific populations at occupational, pharmacological or environmental exposures. Current knowledge of human genome open up the possibility of individual genetic screening of disease susceptibility among those exposed in workplaces to chemical or physical hazards, or for late onset hereditary disease. Epidemiological studies including genetic and molecular biology approaches have been designed to evaluate the interaction of genetically determined metabolic variants with different environmental exposures on the risk of diseases. The strategy for worker's health promotion must be

Cis-to- Trans Isomerization of Azobenzene Derivatives Studied with Transition Path Sampling and Quantum Mechanical/Molecular Mechanical Molecular Dynamics.

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Muždalo, Anja; Saalfrank, Peter; Vreede, Jocelyne; Santer, Mark

2018-04-10

Azobenzene-based molecular photoswitches are becoming increasingly important for the development of photoresponsive, functional soft-matter material systems. Upon illumination with light, fast interconversion between a more stable trans and a metastable cis configuration can be established resulting in pronounced changes in conformation, dipole moment or hydrophobicity. A rational design of functional photosensitive molecules with embedded azo moieties requires a thorough understanding of isomerization mechanisms and rates, especially the thermally activated relaxation. For small azo derivatives considered in the gas phase or simple solvents, Eyring's classical transition state theory (TST) approach yields useful predictions for trends in activation energies or corresponding half-life times of the cis isomer. However, TST or improved theories cannot easily be applied when the azo moiety is part of a larger molecular complex or embedded into a heterogeneous environment, where a multitude of possible reaction pathways may exist. In these cases, only the sampling of an ensemble of dynamic reactive trajectories (transition path sampling, TPS) with explicit models of the environment may reveal the nature of the processes involved. In the present work we show how a TPS approach can conveniently be implemented for the phenomenon of relaxation-isomerization of azobenzenes starting with the simple examples of pure azobenzene and a push-pull derivative immersed in a polar (DMSO) and apolar (toluene) solvent. The latter are represented explicitly at a molecular mechanical (MM) and the azo moiety at a quantum mechanical (QM) level. We demonstrate for the push-pull azobenzene that path sampling in combination with the chosen QM/MM scheme produces the expected change in isomerization pathway from inversion to rotation in going from a low to a high permittivity (explicit) solvent model. We discuss the potential of the simulation procedure presented for comparative calculation of

Graph-drawing algorithms geometries versus molecular mechanics in fullereness

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Kaufman, M.; Pisanski, T.; Lukman, D.; Borštnik, B.; Graovac, A.

1996-09-01

The algorithms of Kamada-Kawai (KK) and Fruchterman-Reingold (FR) have been recently generalized (Pisanski et al., Croat. Chem. Acta 68 (1995) 283) in order to draw molecular graphs in three-dimensional space. The quality of KK and FR geometries is studied here by comparing them with the molecular mechanics (MM) and the adjacency matrix eigenvectors (AME) algorithm geometries. In order to compare different layouts of the same molecule, an appropriate method has been developed. Its application to a series of experimentally detected fullerenes indicates that the KK, FR and AME algorithms are able to reproduce plausible molecular geometries.

Quality assurance practices in Europe: a survey of molecular genetic testing laboratories

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Berwouts, Sarah; Fanning, Katrina; Morris, Michael A; Barton, David E; Dequeker, Elisabeth

2012-01-01

In the 2000s, a number of initiatives were taken internationally to improve quality in genetic testing services. To contribute to and update the limited literature available related to this topic, we surveyed 910 human molecular genetic testing laboratories, of which 291 (32%) from 29 European countries responded. The majority of laboratories were in the public sector (81%), affiliated with a university hospital (60%). Only a minority of laboratories was accredited (23%), and 26% was certified. A total of 22% of laboratories did not participate in external quality assessment (EQA) and 28% did not use reference materials (RMs). The main motivations given for accreditation were to improve laboratory profile (85%) and national recognition (84%). Nearly all respondents (95%) would prefer working in an accredited laboratory. In accredited laboratories, participation in EQA (Pquality assurance (Pquality implementation score (QIS), we showed that accredited laboratories (average score 92) comply better than certified laboratories (average score 69, Pquality indicators. We conclude that quality practices vary widely in European genetic testing laboratories. This leads to a potentially dangerous situation in which the quality of genetic testing is not consistently assured. PMID:22739339

Synthetic biology and molecular genetics in non-conventional yeasts: Current tools and future advances.

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Wagner, James M; Alper, Hal S

2016-04-01

Coupling the tools of synthetic biology with traditional molecular genetic techniques can enable the rapid prototyping and optimization of yeast strains. While the era of yeast synthetic biology began in the well-characterized model organism Saccharomyces cerevisiae, it is swiftly expanding to include non-conventional yeast production systems such as Hansenula polymorpha, Kluyveromyces lactis, Pichia pastoris, and Yarrowia lipolytica. These yeasts already have roles in the manufacture of vaccines, therapeutic proteins, food additives, and biorenewable chemicals, but recent synthetic biology advances have the potential to greatly expand and diversify their impact on biotechnology. In this review, we summarize the development of synthetic biological tools (including promoters and terminators) and enabling molecular genetics approaches that have been applied in these four promising alternative biomanufacturing platforms. An emphasis is placed on synthetic parts and genome editing tools. Finally, we discuss examples of synthetic tools developed in other organisms that can be adapted or optimized for these hosts in the near future. Copyright © 2015 Elsevier Inc. All rights reserved.

Cystic fibrosis, molecular genetics for all life

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Ausilia Elce

2015-10-01

Full Text Available Cystic fibrosis (CF is the most frequent lethal autosomal recessive disorder among Caucasians (incidence: 1:2,500 newborn. In the last two decades CF prognosis considerably improved and many patients well survive into their adulthood. Furthermore, milder CF with a late onset was described. CF is a challenge for laboratory of molecular genetics that greatly contributes to the natural history of the disease since fetal age. Carrier screening and prenatal diagnosis, also by non-invasive analysis of maternal blood fetal DNA, are now available, and many labs offer preimplantation diagnosis. The major criticism in prenatal medicine is the lack of an effective multidisciplinary counseling that helps the couples to plan their reasoned reproductive choice. Most countries offer newborn screening that significantly reduce CF morbidity but different protocols based on blood trypsin, molecular analysis and sweat chloride cause a variable efficiency of the screening programs. Again, laboratory is crucial for CF diagnosis in symptomatic patients: sweat chloride is the diagnostic golden standard, but different methodologies and the lack of quality control in most labs reduce its effectiveness. Molecular analysis contributes to confirm diagnosis in symptomatic subjects; furthermore, it helps to predict the disease outcome on the basis of the mutation (genotype-phenotype correlation and mutations in a myriad of genes, inherited independently by CF transmembrane conductance regulator (CFTR, which may modulate the clinical expression of the disease in each single patient (modifier genes. More recently, the search of the CFTR mutations gained a role in selecting CF patients that may benefit from biological therapy based on correctors and potentiators that are effective in patients bearing specific mutations (personalized therapy. All such applications of molecular diagnostics confirm the “uniqueness” of each CF patient, offering to laboratory medicine the

Genetic approaches in comparative and evolutionary physiology

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Bridgham, Jamie T.; Kelly, Scott A.; Garland, Theodore

2015-01-01

Whole animal physiological performance is highly polygenic and highly plastic, and the same is generally true for the many subordinate traits that underlie performance capacities. Quantitative genetics, therefore, provides an appropriate framework for the analysis of physiological phenotypes and can be used to infer the microevolutionary processes that have shaped patterns of trait variation within and among species. In cases where specific genes are known to contribute to variation in physiological traits, analyses of intraspecific polymorphism and interspecific divergence can reveal molecular mechanisms of functional evolution and can provide insights into the possible adaptive significance of observed sequence changes. In this review, we explain how the tools and theory of quantitative genetics, population genetics, and molecular evolution can inform our understanding of mechanism and process in physiological evolution. For example, lab-based studies of polygenic inheritance can be integrated with field-based studies of trait variation and survivorship to measure selection in the wild, thereby providing direct insights into the adaptive significance of physiological variation. Analyses of quantitative genetic variation in selection experiments can be used to probe interrelationships among traits and the genetic basis of physiological trade-offs and constraints. We review approaches for characterizing the genetic architecture of physiological traits, including linkage mapping and association mapping, and systems approaches for dissecting intermediary steps in the chain of causation between genotype and phenotype. We also discuss the promise and limitations of population genomic approaches for inferring adaptation at specific loci. We end by highlighting the role of organismal physiology in the functional synthesis of evolutionary biology. PMID:26041111

Crosstalk between Apoptosis and Autophagy: Molecular Mechanisms and Therapeutic Strategies in Cancer

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Abdelouahid El-Khattouti

2013-01-01

Full Text Available Both apoptosis and autophagy are highly conserved processes that besides their role in the maintenance of the organismal and cellular homeostasis serve as a main target of tumor therapeutics. Although their important roles in the modulation of tumor therapeutic strategies have been widely reported, the molecular actions of both apoptosis and autophagy are counteracted by cancer protective mechanisms. While apoptosis is a tightly regulated process that is implicated in the removal of damaged or unwanted cells, autophagy is a cellular catabolic pathway that is involved in lysosomal degradation and recycling of proteins and organelles, and thereby is considered an important survival/protective mechanism for cancer cells in response to metabolic stress or chemotherapy. Although the relationship between autophagy and cell death is very complicated and has not been characterized in detail, the molecular mechanisms that control this relationship are considered to be a relevant target for the development of a therapeutic strategy for tumor treatment. In this review, we focus on the molecular mechanisms of apoptosis, autophagy, and those of the crosstalk between apoptosis and autophagy in order to provide insight into the molecular mechanisms that may be essential for the balance between cell survival and death as well as their role as targets for the development of novel therapeutic approaches.

genetics, epigenetics and the story of mutual antagonisms

Indian Academy of Sciences (India)

Recent years have seen a rapid growth in mouse genetics resources that support research into fundamental mechanisms in organogenesis, including those controlling mammalian sex determinations. Numerous mouse mutants have shed light on molecular pathways of cell fate specification during gonadogenesis and the ...

Molecular Mechanisms Underlying Hepatocellular Carcinoma

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Christian Trepo

2009-11-01

Full Text Available Hepatocarcinogenesis is a complex process that remains still partly understood. That might be explained by the multiplicity of etiologic factors, the genetic/epigenetic heterogeneity of tumors bulks and the ignorance of the liver cell types that give rise to tumorigenic cells that have stem cell-like properties. The DNA stress induced by hepatocyte turnover, inflammation and maybe early oncogenic pathway activation and sometimes viral factors, leads to DNA damage response which activates the key tumor suppressive checkpoints p53/p21Cip1 and p16INK4a/pRb responsible of cell cycle arrest and cellular senescence as reflected by the cirrhosis stage. Still obscure mechanisms, but maybe involving the Wnt signaling and Twist proteins, would allow pre-senescent hepatocytes to bypass senescence, acquire immortality by telomerase reactivation and get the last genetic/epigenetic hits necessary for cancerous transformation. Among some of the oncogenic pathways that might play key driving roles in hepatocarcinogenesis, c-myc and the Wnt/β-catenin signaling seem of particular interest. Finally, antiproliferative and apoptosis deficiencies involving TGF-β, Akt/PTEN, IGF2 pathways for instance are prerequisite for cancerous transformation. Of evidence, not only the transformed liver cell per se but the facilitating microenvironment is of fundamental importance for tumor bulk growth and metastasis.

[Molecular genetic analysis and clinical aspects of patients with hereditary hemochromatosis].

Science.gov (United States)

Lange, U; Teichmann, J; Dischereit, G

2014-08-01

The purpose of the study was to perform a molecular genetic analysis and to document clinical aspects in patients with hereditary hemochromatosis. The study included 33 outpatients (23 males average age 50.6 years and 10 females average age 60.6 years) with a disorder of iron metabolism (transferrin saturation > 75 %) as confirmation of hemochromatosis who were subjected to molecular genetic and clinical analyses. A homozygous mutation of the hemochromatosis (HFE) gene (C282YY) was detected in 63.6 %, a compound heterozygous mutation (C282Y/H63D) in 30.3% and no mutation of the HFE gene was detected in 6.1 %. The following organ manifestations could be objectified: arthralgia (78.8 %), liver disease (39.9 %), skin hyperpigmentation (30.3 %), osteoporosis (24.2 %), diabetes mellitus (24.2 %) and cardiomyopathy (12.1 %). Comparison between patients with heterozygous and homozygous hemochromatosis revealed the following differences: compound heterozygote patients presented less frequently with osteoarthritis of the metacarpophalangeal (MCP) joints and hands (85.7 %/71.4 % homozygotes vs. 60 %/60 % heterozygotes). Osteoarthritis of the shoulder joints and osteoporosis as well as hypothyroidism were more frequent in compound heterozygote patients, whereas osteoarthritis of the knee and hip joints as well as liver disease were more common in homozygote patients. No differences between both groups were seen with respect to the clinical manifestations of cardiomyopathy and diabetes mellitus. Prevalent causes of death in hereditary hemochromatosis are heart failure, liver disease (cirrhosis and hepatocellular carcinoma) and portal hypertension. Therefore, an early diagnosis, adequate therapy and genetic screening of family members are of great importance. Medicinal treatment will only effectively prevent deleterious organ involvement and subsequent complications if initiated at an early stage. Furthermore, an overview of the current data is given.

Variabilidade genética de acessos de maracujá-suspiro com base em marcadores moleculares Genetic variability of wild passion fruit determined by molecular markers

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Keize Pereira Junqueira

2007-01-01

Full Text Available Passiflora nitida é uma espécie silvestre amplamente distribuída pelo território brasileiro, constituindo-se em fonte de resistência a doenças foliares e de raízes. O objetivo deste trabalho foi avaliar a variabilidade genética entre acessos de P. nitida procedentes de diferentes tipos fitofisionômicos de Cerrado e estados brasileiros (Goiás, Distrito Federal, Tocantins, Mato Grosso e Amazonas, usando marcadores moleculares RAPD. O DNA genômico de cada acesso foi extraído, e doze iniciadores decâmeros foram utilizados para a obtenção de marcadores moleculares RAPD, que foram convertidos em matriz de dados binários, a partir da qual foram estimadas as distâncias genéticas entre os acessos e realizadas análises de agrupamento e de dispersão gráfica. Foram obtidos 196 marcadores para P. nitida, dos quais 63,81% foram polimórficos. As distâncias genéticas entre os acessos de maracujá variaram de 0,031 a 0,614 e, considerando apenas P. nitida, de 0,031 a 0,417. Os marcadores moleculares demonstraram alta variabilidade genética dos acessos de P. nitida. Menores distâncias genéticas foram verificadas entre os acessos originados do mesmo estado. Considerando-se os acessos de um mesmo estado, menores distâncias genéticas foram verificadas entre os acessos provenientes de tipos fitofisionômicos próximos. O acesso "Manaus 2" apresentou o maior distanciamento genético em relação aos demais acessos.Passiflora nitida is a wild species widely distributed in Brazilian territory. It is a source of resistance to foliar and soil borne diseases. The objective of this work was to evaluate the genetic variability among accessions of P. nitida proceeding from different types of Cerrado (Brazilian savannah vegetation and brazilian states (Goiás, Distrito Federal, Tocantins, Mato Grosso and Amazonas using RAPD molecular markers. The genomic DNA of each origin was extracted and amplified using 12 decamer primers to obtain RAPD

Molecular Mechanisms of Chromium in Alleviating Insulin Resistance

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Hua, Yinan; Clark, Suzanne; Ren, Jun; Sreejayan, Nair

2011-01-01

Type 2 diabetes is often associated with obesity, dyslipidemia, and cardiovascular anomalies and is a major health problem approaching global epidemic proportions. Insulin resistance, a prediabetic condition, precedes the onset of frank type 2 diabetes and offers potential avenues for early intervention to treat the disease. Although lifestyle modifications and exercise can reduce the incidence of diabetes, compliance has proved to be difficult, warranting pharmacological interventions. However, most of the currently available drugs that improve insulin sensitivity have adverse effects. Therefore, attractive strategies to alleviate insulin resistance include dietary supplements. One such supplement is chromium, which has been shown reduce insulin resistance in some, but not all, studies. Furthermore, the molecular mechanisms of chromium in alleviating insulin resistance remain elusive. This review examines emerging reports on the effect of chromium, as well as molecular and cellular mechanisms by which chromium may provide beneficial effects in alleviating insulin resistance. PMID:22423897

Molecular evolution of avian reovirus: evidence for genetic diversity and reassortment of the S-class genome segments and multiple cocirculating lineages

International Nuclear Information System (INIS)

Liu, Hung J.; Lee, Long H.; Hsu, Hsiao W.; Kuo, Liam C.; Liao, Ming H.

2003-01-01

Nucleotide sequences of the S-class genome segments of 17 field-isolates and vaccine strains of avian reovirus (ARV) isolated over a 23-year period from different hosts, pathotypes, and geographic locations were examined and analyzed to define phylogenetic profiles and evolutionary mechanism. The S1 genome segment showed noticeably higher divergence than the other S-class genes. The σC-encoding gene has evolved into six distinct lineages. In contrast, the other S-class genes showed less divergence than that of the σC-encoding gene and have evolved into two to three major distinct lineages, respectively. Comparative sequence analysis provided evidence indicating extensive sequence divergence between ARV and other orthoreoviruses. The evolutionary trees of each gene were distinct, suggesting that these genes evolve in an independent manner. Furthermore, variable topologies were the result of frequent genetic reassortment among multiple cocirculating lineages. Results showed genetic diversity correlated more closely with date of isolation and geographic sites than with host species and pathotypes. This is the first evidence demonstrating genetic variability among circulating ARVs through a combination of evolutionary mechanisms involving multiple cocirculating lineages and genetic reassortment. The evolutionary rates and patterns of base substitutions were examined. The evolutionary rate for the σC-encoding gene and σC protein was higher than for the other S-class genes and other family of viruses. With the exception of the σC-encoding gene, which nonsynonymous substitutions predominate over synonymous, the evolutionary process of the other S-class genes can be explained by the neutral theory of molecular evolution. Results revealed that synonymous substitutions predominate over nonsynonymous in the S-class genes, even though genetic diversity and substitution rates vary among the viruses

The human pain genetics database: an interview with Luda Diatchenko.

Science.gov (United States)

Diatchenko, Luda

2018-06-05

Luda Diatchenko, MD, PhD is a Canada Excellence Research Chair in Human Pain Genetics, Professor, Faculty of Medicine, Department of Anesthesia and Faculty of Dentistry at McGill University, Alan Edwards Centre for Research on Pain. She earned her MD and PhD in the field of molecular biology from the Russian State Medical University. She started her career in industry, she was a Leader of the RNA Expression Group at Clontech, Inc., and subsequently, Director of Gene Discovery at Attagene, Inc. During this time, she was actively involved in the development of several widely used and widely cited molecular tools for the analysis of gene expression and regulation. Her academic career started at 2000 in the Center for Neurosensory Disorders at University of North Carolina. Her research since then is focused on determining the cellular and molecular biological mechanisms by which functional genetic variations impact human pain perception and risk of development of chronic pain conditions, enabling new approaches to identify new drug targets, treatment responses to analgesics and diagnostic. Multiple collaborative activities allow the Diatchenko group to take basic genetic findings all the way from human association studies, through molecular and cellular mechanisms to animal models and ultimately to human clinical trials. In total, she has authored or co-authored over 120 peer-reviewed research papers in journals, ten book chapters and edited a book in human pain genetics. She is a member and an active officer of several national and international scientific societies, including the International Association for the Study of Pain and the American Pain Society.

Mechanical and molecular studies of biocomposites filled with oil palm empty fruit bunches microfibers

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Nikmatin, S.; Saepulloh, D. R.; Irmansyah; Syafiuddin, A.

2017-05-01

The present work aims to investigate mechanical and molecular characteristics of acrylonitrile butadiene styrene (ABS) composites filled with oil palm empty fruit bunches (OPEFB) microfibers. OPEFB microfibers were produced using mechanical milling. Composite granules were fabricated using single screw extruder. These composites were then used for fabricating helmet according to the Indonesian National Standard (SNI). Mechanical testing confirms that the helmet produced using this biocomposites are suitable to the SNI. Molecular interaction between matrix with OPEFB can be described using orbital hybridization theory. In general, this study has successfully investigated mechanical and molecular properties of the biocomposites.

Genetics of SCID

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Cossu Fausto

2010-11-01

Full Text Available Abstract Human SCID (Severe Combined Immunodeficiency is a prenatal disorder of T lymphocyte development, that depends on the expression of numerous genes. The knowledge of the genetic basis of SCID is essential for diagnosis (e.g., clinical phenotype, lymphocyte profile and treatment (e.g., use and type of pre-hematopoietic stem cell transplant conditioning. Over the last years novel genetic defects causing SCID have been discovered, and the molecular and immunological mechanisms of SCID have been better characterized. Distinct forms of SCID show both common and peculiar (e.g., absence or presence of nonimmunological features aspects, and they are currently classified into six groups according to prevalent pathophysiological mechanisms: impaired cytokine-mediated signaling; pre-T cell receptor defects; increased lymphocyte apoptosis; defects in thymus embryogenesis; impaired calcium flux; other mechanisms. This review is the updated, extended and largely modified translation of the article "Cossu F: Le basi genetiche delle SCID", originally published in Italian language in the journal "Prospettive in Pediatria" 2009, 156:228-238.

Congruence between morphological and molecular markers inferred from the analysis of the intra-morphotype genetic diversity and the spatial structure of Oxalis tuberosa Mol.

Science.gov (United States)

Pissard, Audrey; Arbizu, Carlos; Ghislain, Marc; Faux, Anne-Michèle; Paulet, Sébastien; Bertin, Pierre

2008-01-01

Oxalis tuberosa is an important crop cultivated in the highest Andean zones. A germplasm collection is maintained ex situ by CIP, which has developed a morphological markers system to classify the accessions into morphotypes, i.e. groups of morphologically identical accessions. However, their genetic uniformity is currently unknown. The ISSR technique was used in two experiments to determine the relationships between both morphological and molecular markers systems. The intra-morphotype genetic diversity, the spatial structures of the diversity and the congruence between both markers systems were determined. In the first experience, 44 accessions representing five morphotypes, clearly distinct from each other, were analyzed. At the molecular level, the accessions exactly clustered according to their morphotypes. However, a genetic variability was observed inside each morphotype. In the second experiment, 34 accessions gradually differing from each other on morphological base were analyzed. The morphological clustering showed no geographical structure. On the opposite, the molecular analysis showed that the genetic structure was slightly related to the collection site. The correlation between both markers systems was weak but significant. The lack of perfect congruence between morphological and molecular data suggests that the morphological system may be useful for the morphotypes management but is not appropriate to study the genetic structure of the oca. The spatial structure of the genetic diversity can be related to the evolution of the species and the discordance between the morphological and molecular structures may result from similar selection pressures at different places leading to similar forms with a different genetic background.

Computation of Hydration Free Energies Using the Multiple Environment Single System Quantum Mechanical/Molecular Mechanical Method.

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König, Gerhard; Mei, Ye; Pickard, Frank C; Simmonett, Andrew C; Miller, Benjamin T; Herbert, John M; Woodcock, H Lee; Brooks, Bernard R; Shao, Yihan

2016-01-12

A recently developed MESS-E-QM/MM method (multiple-environment single-system quantum mechanical molecular/mechanical calculations with a Roothaan-step extrapolation) is applied to the computation of hydration free energies for the blind SAMPL4 test set and for 12 small molecules. First, free energy simulations are performed with a classical molecular mechanics force field using fixed-geometry solute molecules and explicit TIP3P solvent, and then the non-Boltzmann-Bennett method is employed to compute the QM/MM correction (QM/MM-NBB) to the molecular mechanical hydration free energies. For the SAMPL4 set, MESS-E-QM/MM-NBB corrections to the hydration free energy can be obtained 2 or 3 orders of magnitude faster than fully converged QM/MM-NBB corrections, and, on average, the hydration free energies predicted with MESS-E-QM/MM-NBB fall within 0.10-0.20 kcal/mol of full-converged QM/MM-NBB results. Out of five density functionals (BLYP, B3LYP, PBE0, M06-2X, and ωB97X-D), the BLYP functional is found to be most compatible with the TIP3P solvent model and yields the most accurate hydration free energies against experimental values for solute molecules included in this study.

Molecular Genetic Insights on Cheetah (Acinonyx jubatus) Ecology and Conservation in Namibia

OpenAIRE

Marker, Laurie L.; Wilkerson, Alison J. Pearks; Sarno, Ronald J.; Martenson, Janice; Breitenmoser-Würsten, Christian; O'Brien, Stephen J.; Johnson, Warren E.

2017-01-01

The extent and geographic patterns of molecular genetic diversity of the largest remaining free-ranging cheetah population were described in a survey of 313 individuals from throughout Namibia. Levels of relatedness, including paternity/maternity (parentage), were assessed across all individuals using 19 polymorphic microsatellite loci, and unrelated cheetahs (n = 89) from 7 regions were genotyped at 38 loci to document broad geographical patterns. There was limited differentiation among regi...

Journal of Genetics | Indian Academy of Sciences

Indian Academy of Sciences (India)

Gene–gene (CFH with ARMS2 and HTRA1) interactions and correlations with environmental traits (smoking and body mass index) have been established as significant covariates in AMD pathology. In this review, we have provided an overview on the underlying molecular genetic mechanisms in AMD worldwide and ...

Molecular Mechanisms in Exercise-Induced Cardioprotection

Directory of Open Access Journals (Sweden)

Saeid Golbidi

2011-01-01

Full Text Available Physical inactivity is increasingly recognized as modifiable behavioral risk factor for cardiovascular diseases. A partial list of proposed mechanisms for exercise-induced cardioprotection include induction of heat shock proteins, increase in cardiac antioxidant capacity, expression of endoplasmic reticulum stress proteins, anatomical and physiological changes in the coronary arteries, changes in nitric oxide production, adaptational changes in cardiac mitochondria, increased autophagy, and improved function of sarcolemmal and/or mitochondrial ATP-sensitive potassium channels. It is currently unclear which of these protective mechanisms are essential for exercise-induced cardioprotection. However, most investigations focus on sarcolemmal KATP channels, NO production, and mitochondrial changes although it is very likely that other mechanisms may also exist. This paper discusses current information about these aforementioned topics and does not consider potentially important adaptations within blood or the autonomic nervous system. A better understanding of the molecular basis of exercise-induced cardioprotection will help to develop better therapeutic strategies.

A quantum mechanical/molecular mechanical study of the hydroxylation of phenol and halogeneted derivatives by phenol hydroxylase

NARCIS (Netherlands)

Ridder, L.; Mulholland, A.J.; Rietjens, I.M.C.M.; Vervoort, J.

2000-01-01

A combined quantum mechanical and molecular mechanical (QM/MM) method (AM1/CHARMM) was used to investigate the mechanism of the aromatic hydroxylation of phenol by a flavin dependent phenol hydroxylase (PH), an essential reaction in the degradation of a wide range of aromatic compounds. The model

Survival under stress: molecular mechanisms of metabolic rate ...

African Journals Online (AJOL)

Studies in my laboratory are analysing the molecular mechanisms and regulatory events that underlie transitions to and from hypometabolic states In systems including anoxia-tolerant turtles and molluscs, estivating snails and toads, hibernating small mammals, and freeze tolerant frogs and insects. Our newest research ...

Avoiding Pitfalls in Molecular Genetic Testing: Case Studies of High-Resolution Array Comparative Genomic Hybridization Testing in the Definitive Diagnosis of Mowat-Wilson Syndrome

OpenAIRE

Kluk, Michael Joseph; An, Yu; James, Philip; Coulter, David; Harris, David; Wu, Bai-Lin; Shen, Yiping

2011-01-01

The molecular testing options available for the diagnosis of genetic disorders are numerous and include a variety of different assay platforms. The consultative input of molecular pathologists and cytogeneticists, working closely with the ordering clinicians, is often important for definitive diagnosis. Herein, we describe two patients who had long histories of unexplained signs and symptoms with a high clinical suspicion of an underlying genetic etiology. Initial molecular testing in both ca...

Understanding the molecular mechanisms of reprogramming

Energy Technology Data Exchange (ETDEWEB)

Krause, Marie N. [Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla 92037, CA (United States); University Hospital of Würzburg, Department of Pediatrics, 2 Josef-Schneiderstrasse, 97080 Würzburg (Germany); Sancho-Martinez, Ignacio [Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla 92037, CA (United States); Centre for Stem Cells and Regenerative Medicine, King' s College London, 28th Floor, Tower Wing, Guy' s Hospital, Great Maze Pond, London (United Kingdom); Izpisua Belmonte, Juan Carlos, E-mail: belmonte@salk.edu [Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla 92037, CA (United States)

2016-05-06

Despite the profound and rapid advancements in reprogramming technologies since the generation of the first induced pluripotent stem cells (iPSCs) in 2006[1], the molecular basics of the process and its implications are still not fully understood. Recent work has suggested that a subset of TFs, so called “Pioneer TFs”, play an important role during the stochastic phase of iPSC reprogramming [2–6]. Pioneer TFs activities differ from conventional transcription factors in their mechanism of action. They bind directly to condensed chromatin and elicit a series of chromatin remodeling events that lead to opening of the chromatin. Chromatin decondensation by pioneer factors progressively occurs during cell division and in turn exposes specific gene promoters in the DNA to which TFs can now directly bind to promoters that are readily accessible[2, 6]. Here, we will summarize recent advancements on our understanding of the molecular mechanisms underlying reprogramming to iPSC as well as the implications that pioneer Transcription Factor activities might play during different lineage conversion processes. - Highlights: • Pioneer transcription factor activity underlies the initial steps of iPSC generation. • Reprogramming can occur by cis- and/or trans- reprogramming events. • Cis-reprogramming implies remodeling of the chromatin for enabling TF accessibility. • Trans-reprogramming encompasses direct binding of Tfs to their target gene promoters.

Molecular Markers and Cotton Genetic Improvement: Current Status and Future Prospects

Directory of Open Access Journals (Sweden)

Waqas Malik

2014-01-01

Full Text Available Narrow genetic base and complex allotetraploid genome of cotton (Gossypium hirsutum L. is stimulating efforts to avail required polymorphism for marker based breeding. The availability of draft genome sequence of G. raimondii and G. arboreum and next generation sequencing (NGS technologies facilitated the development of high-throughput marker technologies in cotton. The concepts of genetic diversity, QTL mapping, and marker assisted selection (MAS are evolving into more efficient concepts of linkage disequilibrium, association mapping, and genomic selection, respectively. The objective of the current review is to analyze the pace of evolution in the molecular marker technologies in cotton during the last ten years into the following four areas: (i comparative analysis of low- and high-throughput marker technologies available in cotton, (ii genetic diversity in the available wild and improved gene pools of cotton, (iii identification of the genomic regions within cotton genome underlying economic traits, and (iv marker based selection methodologies. Moreover, the applications of marker technologies to enhance the breeding efficiency in cotton are also summarized. Aforementioned genomic technologies and the integration of several other omics resources are expected to enhance the cotton productivity and meet the global fiber quantity and quality demands.

Molecular and Genetic Analysis of Hormone-Regulated Differential Cell Elongation in Arabidopsis

Energy Technology Data Exchange (ETDEWEB)

Ecker, Joseph R.

2005-09-15

We have utilized the response of Arabidopsis seedlings to the plant hormone ethylene to identify new genes involved in the regulation of ethylene biosynthesis, perception, signal transduction and differential cell growth. In building a genetic framework for the action of these genes, we have developed a molecular model that has facilitated our understanding of the molecular requirements of ethylene for cell elongation processes. The ethylene response pathway in Arabidopsis appears to be primarily linear and is defined by the genes: ETR1, ETR2, ERS1, ERS2, EIN4, CTR1, EIN2, EIN3, EIN5, EIN6, and EIN. Downstream branches identified by the HLS1, EIR1, and AUX1 genes involve interactions with other hormonal (auxin) signals in the process of differential cell elongation in the hypocotyl hook. Cloning and characterization of HLS1 (and three HLL genes) and ETO1 (and ETOL genes) in my laboratory has been supported under this award. HLS1 is required for differential elongation of cells in the hypocotyl and may act in the establishment of hormone gradients. Also during the previous period, we have identified and characterized a gene that genetically acts upstream of the ethylene receptors. ETO1 encodes negative regulators of ethylene biosynthesis.

Molecular and Genetic Investigation of Tau in Chronic Traumatic Encephalopathy (Log No. 13267017)

Science.gov (United States)

2017-10-01

AWARD NUMBER: W81XWH-14-1-0399 TITLE: Molecular & Genetic Investigation of Tau in Chronic Traumatic Encephalopathy (Log No. 13267017) PRINCIPAL...this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data ...sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden

Biochemical and molecular study of genetic stability in tomatoes plants rom seeds treated with low doses of X-ray

International Nuclear Information System (INIS)

Ramirez, R; Gonzalez, LM; Chavez, Licet; Camejo, Yanelis; Gonzalez, Maria C; Fernandez, Arais

2008-01-01

For the extensive agricultural exploitation of vegetable radio stimulation, it is indispensable to study the genetic stability of treated varieties, having in mind X ray potentialities of inducing not only physiological but genetic changes as well. Therefore, biochemical and molecular markers were employed in tomato plants derived from irradiated seeds at low doses of X rays. For the biochemical analysis, peroxidases, polyphenoloxidases and dismutase superoxide isoenzymes were determined whereas the Random Amplification of Polymorphic DNA (RAPD) method based on Polymerase Chain Reaction (PCR) was used for the molecular analysis. When comparing the electrophoretic patterns from the control and irradiated treatments applied to the three enzymatic systems, there were not appreciable variations on the number of bands and their intensities, indicating the little variability induced in these systems by the low X ray doses. Also, from the molecular viewpoint, electrophoretic patterns showed a clear amplification of DNA by generating a total of 155 bands in all varieties studied. This molecular marker showed a high monomorphism independently of the treatments applied, with values ranging between 86 and 97 %, indicating that irradiation at low doses did not induce an important genetic variability and confirming its possible practical usefulness for stimulating some physiological processes without causing. (Author)

Molecular mechanics work station for protein conformational studies

International Nuclear Information System (INIS)

Fine, R.; Levinthal, C.; Schoenborn, B.; Dimmier, G.; Rankowitz, C.

1984-01-01

Interest in computational problems in Biology has intensified over the last few years, partly due to the development of techniques for the rapid cloning, sequencing, and mutagenesis of genes from organisims ranging from E. coli to Man. The central dogma of molecular biology; that DNA codes for mRNA which codes for protein, has been understood in a linear programming sense since the genetic code was cracked. But what is not understood at present is how a protein, once assembled as a long sequence of amino acids, folds back on itself to produce a three-dimensional structure which is unique to that protein and which dictates its chemical and biological activity. This folding process is purely physics, and involves the time evolution of a system of several thousand atoms which interact with each other and with atoms from the surrounding solvent. Molecular dynamics simulations on smaller molecules suggest that approaches which treat the protein as a classical ensemble of atoms interacting with each other via an empirical Hamiltonian can yield the kind of predictive results one would like when applied to proteins

Genetic and molecular dosimetry of HZE radiation (US-1 RADIAT)

Science.gov (United States)

Nelson, Gregory A.; Schubert, W. W.; Kazarians, G. A.; Richards, G. F.; Benton, E. V.; Benton, E. R.; Henke, R. P.

1995-01-01

In order to estimate radiation exposure in space, experiments were conducted during the 1st International Microgravity Laboratory (IML-1) mission in order to isolate genetic changes in animal cells caused by cosmic rays. The space measurements were evaluated against results from synthetic cosmic rays produced by particle accelerators on the ground. The biological material used was the tiny soil nematode, Caenorhabditis elegans. The measurements were made by thermoluminescent detectors and plastic nuclear track detectors. The development and the chromosome mechanics in microgravity were studied, and the mutagenesis induced by radiation exposure was analyzed. The results showed that there are no obvious differences in the development, behavior and chromosome mechanics, as a function of gravity unloading (reproduction, self-fertilization and mating of males with hermaphrodites, gross anatomy, symmetry and gametogenesis, pairing, disjoining and recombination of chromosomes). A variety of mutants were isolated, and it was noted that mutants isolated from regions of identified high particles were more severely affected than those isolated by random screening. Linear energy transfer particles seem to favor large scale genetic lesions.

Programmed necrosis and necroptosis – molecular mechanisms

Directory of Open Access Journals (Sweden)

Agata Giżycka

2015-12-01

Full Text Available Programmed necrosis has been proven vital for organism development and homeostasis maintenance. Its regulatory effects on functional activity of the immune system, as well as on pathways regulating the death mechanisms in cells with diminished apoptotic activity, including malignant cells, have been confirmed. There is also increasing evidence indicating necrosis involvement in many human pathologies. Contrary to previous beliefs, necrosis is not only a passive, pathological, gene-independent process. However, the current knowledge regarding molecular regulation of programmed necrosis is scarce. In part this is due to the multiplicity and complexity of signaling pathways involved in programmed necrosis, as well as the absence of specific cellular markers identifying this process, but also the ambiguous and imprecise international terminology. This review presents the current state of the art on molecular mechanisms of programmed necrosis. In particular, its specific and frequent form, necroptosis, is discussed. The role of RIP1 and RIP3 kinases in this process is presented, as well as the diverse pathways induced by ligation of tumor necrosis factor α, to its receptor, TNFR1, i.e. cell survival, apoptosis or necroptosis.