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Heat shock protein 47â¯kDa (HSP47) serves as a client-specific chaperone, essential for collagen biosynthesis and its folding and structural assembly. To date, there is no comprehensive study on mutational hotspots. Using five different human mutational databases, we deduced a comprehensive list of human HSP47 mutations with 24, 67, 50, 43 and 2 deleterious mutations from the 1000 genomes data, gnomAD, COSMICv86, cBioPortal, and CanVar, respectively. We identified thirteen top-ranked missense mutations of HSP47 with the stringent cut-off of CADD score (>25) and Grantham score (≥151) as Ser76Trp, Arg103Cys, Arg116Cys, Ser159Phe, Arg167Cys, Arg280Cys, Trp293Cys, Gly323Trp, Arg339Cys, Arg373Cys, Arg377Cys, Ser399Phe, and Arg405Cys with the arginine-cysteine changes as the predominant mutations. These findings will assist in the evaluation of roles of HSP47 in collagen misfolding and human diseases such as cancer and bone disorders.
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Proteínas de Choque Térmico HSP47/genética , Mutação de Sentido Incorreto , Neoplasias/genética , Doenças Ósseas/genética , Bases de Dados de Ácidos Nucleicos , Proteínas de Choque Térmico HSP47/química , Humanos , Conformação ProteicaRESUMO
After human genome sequencing and rapid changes in genome sequencing methods, we have entered into the era of rapidly accumulating genome-sequencing data. This has derived the development of several types of methods for representing results of genome sequencing data. Circular genome visual-ization tools are also critical in this area as they provide rapid interpretation and simple visualization of overall data. In the last 15 years, we have seen rapid changes in circular visualization tools after the de-velopment of the circos tool with 1-2 tools published per year. Herein we have summarized and revisited all these tools until the third quarter of 2018.
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In sensory circuits of the brain, developmental changes in the expression and modulation of voltage-gated ion channels are a common occurrence, but such changes are often difficult to assign to clear functional roles. We have explored this issue in the binaural neurons of the medial superior olive (MSO), whose temporal precision in detecting the coincidence of binaural inputs dictates the resolution of azimuthal sound localization. We show that in MSO principal neurons of gerbils during the first week of hearing, a hyperpolarization-activated current (I(h)) progressively undergoes a 13-fold increase in maximal conductance, a >10-fold acceleration of kinetics, and, most surprisingly, a 30 mV depolarizing shift in the voltage dependence of activation. This period is associated with an upregulation of the hyperpolarization-activated and cyclic nucleotide-gated (HCN) channel subunits HCN1, HCN2, and HCN4 in the MSO, but only HCN1 and HCN4 were expressed strongly in principal neurons. I(h) recorded in nucleated patches from electrophysiologically mature MSO neurons (>P18) exhibited kinetics and an activation range nearly identical to the I(h) found in whole-cell recordings before hearing onset. These results indicate that the developmental changes in I(h) in MSO neurons can be explained predominantly by modulation from diffusible intracellular factors, and not changes in channel subunit composition. The exceptionally large modulatory changes in I(h), together with refinements in synaptic properties transform the coding strategy from one of summation and integration to the submillisecond coincidence detection known to be required for transmission of sound localization cues.
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Fenômenos Biofísicos/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Ativação do Canal Iônico/fisiologia , Neurônios/fisiologia , Fatores Etários , Análise de Variância , Androstadienos/farmacologia , Animais , Fenômenos Biofísicos/efeitos dos fármacos , Bucladesina/farmacologia , Colforsina/farmacologia , Canais de Cátion Regulados por Nucleotídeos Cíclicos/genética , Canais de Cátion Regulados por Nucleotídeos Cíclicos/metabolismo , Estimulação Elétrica , Inibidores Enzimáticos/farmacologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Gerbillinae , Imidazóis/farmacologia , Técnicas In Vitro , Ativação do Canal Iônico/efeitos dos fármacos , Masculino , Neurônios/efeitos dos fármacos , Núcleo Olivar/citologia , Núcleo Olivar/crescimento & desenvolvimento , Técnicas de Patch-Clamp , Piridinas/farmacologia , Pirimidinas/farmacologia , WortmaninaRESUMO
With increasing use of various techniques to record optically and electrophysiologically from awake behaving animals and the growing developments of brain-machine interfaces, one might wonder if the use of acute-slice physiology is on its deathbed. Have we actually arrived at a stage where we can abandon the use of acute slices, with most of the information about brain functions coming from in vivo experiments? We do not believe that this is the case, given that our understanding of the nuts and bolts of the nervous system, such as ion channels and transporters in near-native state, neuronal compartmentalization, and single-neuron computation, is far from complete. We believe that in the foreseeable future, questions in these fields will still be best addressed by acute-slice physiology. We approach this review from the perspective of improving acute-slice physiology so it can continue to provide relevant and valuable contributions to neuroscience. We conclude that the death of acute-slice physiology is an obituary prematurely written, merely due to waxing and waning trends in science and the shortsightedness of investigators. Acute-slice physiology has at least one more life to live after the hype around new techniques has passed, but it needs to reinvent itself in light of current knowledge.
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Encéfalo/citologia , Eletrofisiologia , Neurônios/fisiologia , Potenciais de Ação/fisiologia , Animais , Morte Celular , Eletrofisiologia/instrumentaçãoRESUMO
We studied complete dose-response curves for 53 odorants in the third instar larvae of Drosophila melanogaster. All odorants, except one, elicited an attraction response. Some odorants also elicited a decrease from their peak response at higher concentrations. This concentration-dependent decrease in olfactory response could be due to either desensitization or repulsion, 2 possibilities that we cannot distinguish in our current assay. We observed high variations in factors like slopes, thresholds, and peaks of responses that, in agreement with previous studies, suggest that the responses of different receptors are quite different for the similar change in concentration of various ligands. We also observed that lower attraction thresholds predicted higher peak amplitude. This suggests that if odor responses encompassed wider concentration range than can be covered by the dynamic range of a single receptor, then responses tend to be high in magnitude.
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Drosophila melanogaster/fisiologia , Odorantes/análise , Animais , Larva/fisiologia , Neurônios Receptores Olfatórios/fisiologia , OlfatoRESUMO
In neurons of the medial superior olive (MSO), voltage-gated ion channels control the submillisecond time resolution of binaural coincidence detection, but little is known about their interplay during trains of synaptic activity that would be experienced during auditory stimuli. Here, using modeling and patch-clamp recordings from MSO principal neurons in gerbil brainstem slices, we examined interactions between two major currents controlling subthreshold synaptic integration: a low-voltage-activated potassium current (I(K-LVA)) and a hyperpolarization-activated cation current (I(h)). Both I(h) and I(K-LVA) contributed strongly to the resting membrane conductance and, during trains of simulated EPSPs, exhibited cumulative deactivation and inactivation, respectively. In current-clamp recordings, regular and irregular trains of simulated EPSCs increased input resistance up to 60%, effects that accumulated and decayed (after train) over hundreds of milliseconds. Surprisingly, the mean voltage and peaks of EPSPs increased by only a few millivolts during trains. Using a model of an MSO cell, we demonstrated that the nearly uniform response during modest depolarizing stimuli relied on changes in I(h) and I(K-LVA), such that their sum remained nearly constant over time. Experiments and modeling showed that, for simplified binaural stimuli (EPSC pairs in a noisy background), spike probability gradually increased in parallel with the increasing input resistance. Nevertheless, the interplay between I(h) and I(K-LVA) helps to maintain a nearly uniform shape of individual synaptic responses, and we show that the time resolution of synaptic coincidence detection can be maintained during trains if EPSC size gradually decreases (as in synaptic depression), counteracting slow increases in excitability.
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Ativação do Canal Iônico/fisiologia , Neurônios/fisiologia , Dinâmica não Linear , Núcleo Olivar/citologia , Canais de Potássio de Abertura Dependente da Tensão da Membrana/fisiologia , Potenciais Sinápticos/fisiologia , Animais , Animais Recém-Nascidos , Biofísica , Cardiotônicos/farmacologia , Simulação por Computador , Estimulação Elétrica/métodos , Feminino , Gerbillinae , Técnicas In Vitro , Ativação do Canal Iônico/efeitos dos fármacos , Masculino , Modelos Neurológicos , Neurônios/efeitos dos fármacos , Distribuição Normal , Técnicas de Patch-Clamp , Peptídeos/farmacologia , Canais de Potássio de Abertura Dependente da Tensão da Membrana/efeitos dos fármacos , Pirimidinas/farmacologia , Potenciais Sinápticos/efeitos dos fármacos , Fatores de TempoRESUMO
Adult Drosophila melanogaster has long been a popular model for learning and memory studies. Now the larval stage of the fruit fly is also being used in an increasing number of classical conditioning studies. In this study, we employed heat shock as a novel negative reinforcement for larvae and obtained high learning scores following just one training trial. We demonstrated heat-shock conditioning in both reciprocal and non-reciprocal paradigms and observed that the time window of association for the odor and heat shock reinforcement is on the order of a few minutes. This is slightly wider than the time window for electroshock conditioning reported in previous studies, possibly due to lingering effects of the high temperature. To test the utility of this simplified assay for the identification of new mutations that disrupt learning, we examined flies carrying mutations in the dnc gene. While the sensitivity to heat shock, as tested by writhing, was similar for wild type and dnc homozygotes, dnc mutations strongly diminished learning. We confirmed that the learning defect in dnc flies was indeed due to mutation in the dnc gene using non-complementation analysis. Given that heat shock has not been employed as a reinforcement for larvae in the past, we explored learning as a function of heat shock intensity and found that optimal learning occurred around 41 °C, with higher and lower temperatures both resulting in lower learning scores. In summary, we have developed a very simple, robust paradigm of learning in fruit fly larvae using heat shock reinforcement.
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Drosophila melanogaster/embriologia , Genética Comportamental/métodos , Resposta ao Choque Térmico/genética , Olfato/genética , Animais , Condicionamento Psicológico , Teste de Complementação Genética , Temperatura Alta , Larva/genética , Aprendizagem , Memória , Modelos Genéticos , Mutação , Odorantes , Reforço PsicológicoRESUMO
Time series tools are part and parcel of modern day research. Their usage in the biomedical field; specifically, in neuroscience, has not been previously quantified. A quantification of trends can tell about lacunae in the current uses and point towards future uses. We evaluated the principles and applications of few classical time series tools, such as Principal Component Analysis, Neural Networks, common Auto-regression Models, Markov Models, Hidden Markov Models, Fourier Analysis, Spectral Analysis, in addition to diverse work, generically lumped under time series category. We quantified the usage from two perspectives, one, information technology professionals', other, researchers utilizing these tools for biomedical and neuroscience research. For understanding trends from the information technology perspective, we evaluated two of the largest open source question and answer databases of Stack Overflow and Cross Validated. We quantified the trends in their application in the biomedical domain, and specifically neuroscience, by searching literature and application usage on PubMed. While the use of all the time series tools continues to gain popularity in general biomedical and life science research, and also neuroscience, and so have been the total number of questions asked on Stack overflow and Cross Validated, the total views to questions on these are on a decrease in recent years, indicating well established texts, algorithms, and libraries, resulting in engineers not looking for what used to be common questions a few years back. The use of these tools in neuroscience clearly leaves room for improvement.
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Maintenance of oral health is a major challenge in dentistry. Different materials have been used to treat various dental diseases, although treatment success is limited by features of the biomaterials used. To overcome these limitations, materials incorporated with nanoparticles (NPs) can be used in dental applications including endodontics, periodontics, tissue engineering, oral surgery, and imaging. The unique properties of NPs, including their surface:volume ratio, antibacterial action, physical, mechanical, and biological characteristics, and unique particle size have rendered them effective vehicles for dental applications. In this review, we provide insights into the various applications of NPs in dentistry, including their benefits, limitations, properties, actions and future potential.
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Materiais Biocompatíveis/uso terapêutico , Nanopartículas/uso terapêutico , Odontologia , HumanosRESUMO
Not much is known about disease prevalence, treatment outcomes, trained manpower, programs, and patients' awareness of diseases from South Asia, compared with the Western world. While other aspects are improving, the quantitative evaluation of awareness of diseases is lagging. Compared with other diseases, the situation for mental health disorders and addiction is worse. While no single study can fully quantify all aspects of awareness, a good starting point is to understand if increasing the number of mental health facilities is beneficial by understanding people's perception toward the likelihood of contracting various diseases, their preferred approach to treatment, and their perception of whether there are enough current facilities. We surveyed over 8000 families across several states of India and asked if they would treat a particular problem at home, visit a local healer, seek religious council, or go to a modern hospital for treatment. Our questions also included non-medical options to assess how likely people are to avoid trained medical help. We also asked people about their perceived likelihood of a family member ever suffering from (1) diarrhea, (2) high fever, (3) alcoholism, and (4) schizophrenia and other mental health problems. We reversed the order of diseases in our questions for a fraction of the population to evaluate the effect of order of questioning. Finally, we asked, if people feel they have enough local healers, religious places, general hospitals, de-addiction centers, and mental health facilities. Despite the taboo around mental health, many people claimed that their family members were unlikely to contract mental health or addiction problems, people recognized the severe paucity of mental health facilities and de-addiction centers. This raises hope for improving the mental health situation in India. We also found a significant relation between education levels and choices people make, underscoring the positive role education has in improving mental health.
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We propose a new approach, Bayesian Probability of Association (BPA) which takes into account the probability distributions of information and noise in the variables and uses Bayesian statistics to predict associations better than existing approaches. Our approach overcomes the limitations of linearity of the relationship and normality of the data, assumed by the Pearson correlation coefficient. It is different from the current measures of association because considering information separately from noise helps identify the association in information more accurately, makes the approach less sensitive to noise and also helps identify causal directions. We tested the approach on 15 datasets with no underlying association and on 75 datasets with known causal relationships and compared the results with other measures of association. No false associations were detected and true associations were predicted in more than 90% cases whereas the Pearson correlation coefficient and mutual information content predicted associations for less than half of the datasets.
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Teorema de Bayes , Simulação por Computador , Interpretação Estatística de Dados , Bases de Dados Factuais/estatística & dados numéricos , Humanos , Teoria da Informação , Dinâmica não Linear , Probabilidade , Razão Sinal-Ruído , SoftwareRESUMO
Phytomedicine has often been used as "alternative therapy," which in our opinion is unfortunate as it prevents its main actions being systematically studied, side effects explored, and toxicity tested, like all single-compound-based medicine. Our group is interested in finding which traditional or modern phytomedicines actually work and which are simply "working" through placebo, standardizing phytomedicine preparations, studying their toxicity, and finding active molecules in plants for modification and chemical synthesis as single compounds. Although fluctuation in efficacy due to seasonal and geographical variations in phytomedicine remains a concern, if well regulated, even plant extracts without isolated compounds can serve medicinal needs where single-compound options are currently not great. A potential concern with such phytomedicine is frequent mixing of ingredients in commercial formulations without test of synergism. Our study on the use of 2 traditional plants for Parkinson disease shows a clear lack of synergism, and to study nonsynergism better, we developed a new visualization approach. In this commentary, using our study on Parkinson disease as an example, we make a case for better evaluation of phytomedicines, especially testing for synergistic interactions. We also critique our own exploration of oxidative stress and few behavioral parameters alone to lay grounds for what we and hopefully others can do in future to extract more information from their phytomedicine studies. We hope this commentary acts as a good warning for anyone mixing 2 phytomedicines without testing.
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Wnts and the components of Wnt/ß-catenin signaling are widely expressed in midbrain and required to control the fate specification of dopaminergic (DAergic) neurons, a neuronal population that specifically degenerate in Parkinson's disease (PD). Accumulating evidence suggest that mitochondrial dysfunction plays a key role in pathogenesis of PD. Axin-2, a negative regulator of Wnt/ß-catenin signaling affects mitochondrial biogenesis and death/birth of new DAergic neurons is not fully explored. We investigated the functional role of Axin-2/Wnt/ß-catenin signaling in mitochondrial biogenesis and DAergic neurogenesis in 6-hydroxydopamine (6-OHDA) induced rat model of PD-like phenotypes. We demonstrate that single unilateral injection of 6-OHDA into the medial forebrain bundle (MFB) potentially dysregulates Wnt/ß-catenin signaling in substantia nigra pars compacta (SNpc). We used shRNA lentiviruses to genetically knockdown Axin-2 to up-regulate Wnt/ß-catenin signaling in SNpc in parkinsonian rats. Genetic knockdown of Axin-2 up-regulates Wnt/ß-catenin signaling by destabilizing the ß-catenin degradation complex in SNpc in parkinsonian rats. Axin-2 shRNA mediated activation of Wnt/ß-catenin signaling improved behavioural functions and protected the nigral DAergic neurons by increasing mitochondrial functionality in parkinsonian rats. Axin-2 shRNA treatment reduced apoptotic signaling, autophagy and ROS generation and improved mitochondrial membrane potential which promotes mitochondrial biogenesis in SNpc in parkinsonian rats. Interestingly, Axin-2 shRNA-mediated up-regulation of Wnt/ß-catenin signaling enhanced net DAergic neurogenesis by regulating proneural genes (Nurr-1, Pitx-3, Ngn-2, and NeuroD1) and mitochondrial biogenesis in SNpc in parkinsonian rats. Therefore, our data suggest that pharmacological/genetic manipulation of Wnt signaling that enhances the endogenous regenerative capacity of DAergic neurons may have implication for regenerative approaches in PD.
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Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas de Transporte/genética , Neurônios Dopaminérgicos/metabolismo , Neurogênese/genética , Doença de Parkinson Secundária/genética , Proteínas Wnt/genética , Via de Sinalização Wnt , beta Catenina/genética , Proteínas Adaptadoras de Transdução de Sinal/antagonistas & inibidores , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proteínas de Transporte/antagonistas & inibidores , Proteínas de Transporte/metabolismo , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/patologia , Regulação da Expressão Gênica , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Injeções Intraventriculares , Masculino , Feixe Prosencefálico Mediano/efeitos dos fármacos , Feixe Prosencefálico Mediano/metabolismo , Feixe Prosencefálico Mediano/patologia , Mesencéfalo/efeitos dos fármacos , Mesencéfalo/metabolismo , Mesencéfalo/patologia , Mitocôndrias/genética , Mitocôndrias/metabolismo , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Biogênese de Organelas , Oxidopamina/administração & dosagem , Doença de Parkinson Secundária/induzido quimicamente , Doença de Parkinson Secundária/metabolismo , Doença de Parkinson Secundária/patologia , Parte Compacta da Substância Negra/efeitos dos fármacos , Parte Compacta da Substância Negra/metabolismo , Parte Compacta da Substância Negra/patologia , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Sprague-Dawley , Técnicas Estereotáxicas , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas Wnt/metabolismo , beta Catenina/metabolismoRESUMO
Parkinson's disease remains as one of the most common debilitating neurodegenerative disorders. With the hopes of finding agents that can cure or reduce the pace of progression of the disease, we studied two traditional medicinal plants: Centella asiatica and Withania somnifera that have been explored in some recent studies. In agreement with the previous work on ethanol extracts of these two plants in mice model, we saw an improvement in oxidative stress profile as well as behavioral performance in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced Parkinson-like symptoms in Balb/c mice. Given the known potential of both the herbal extracts in improving Parkinson-like symptoms, we expected the combination of the two to show better results than either of the two but surprisingly there was no additivity in either oxidative stress or behavioural recovery. In fact, in some assays, the combination performed worse than either of the two individual constituents. This effect of mixtures highlights the need of testing mixtures in supplements market using enthomedicine. The necessity of comparing multiple groups in this study to get most information from the experiments motivated us to design a ladder-like visualization to show comparison with different groups that we call complete comparison display (CCD). In summary, we show the potential of Centella asiatica and Withania somnifera to ameliorate Parkinson's disorder.
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Antiparkinsonianos/farmacologia , Comportamento Animal/efeitos dos fármacos , Doença de Parkinson/patologia , Doença de Parkinson/fisiopatologia , Extratos Vegetais/farmacologia , Triterpenos/farmacologia , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/efeitos adversos , Animais , Biomarcadores , Caspases/metabolismo , Centella , Modelos Animais de Doenças , Glutationa/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Camundongos , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/etiologia , Superóxido Dismutase/metabolismo , Withania/químicaRESUMO
Many insects, including Drosophila melanogaster, have a rich repertoire of olfactory behavior. Combination of robust behavioral assays, physiological and molecular tools render D. melanogaster as highly suitable system for olfactory studies. The small number of neurons in the olfactory system of fruit flies, especially the number of sensory neurons in the larval stage, makes the exploration of sensory coding at all stages of its nervous system a potentially tractable goal, which is not possible in the foreseeable future in any mammalian preparation. Advances in physiological recordings, olfactory signaling and detailed analysis of behavior, can place larvae in a position to ask previously unanswerable questions.
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Gelling agents are required for formulating both solid and semisolid media, vital for the isolation of microorganisms. Gelatin was the first gelling agent to be discovered but it soon paved the way for agar, which has far superior material qualities. Source depletion, issues with polymerase-chain-reaction and inability to sustain extermophiles etc., necessitate the need of other gelling agents. Many new gelling agents, such as xantham gum, gellan gum, carrageenan, isubgol, and guar gum have been formulated, raising the hopes for the growth of previously unculturable microorganisms. We evaluate the progress in the development of gelling agents, with the hope that our synthesis would help accelerate research in the field.
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Parkinson's disease is one of the most common neurodegenerative diseases. Animal models have contributed a large part to our understanding and therapeutics developed for treatment of PD. There are several more exhaustive reviews of literature that provide the initiated insights into the specific models; however a novel synthesis of the basic advantages and disadvantages of different models is much needed. Here we compare both neurotoxin based and genetic models while suggesting some novel avenues in PD modeling. We also highlight the problems faced and promises of all the mammalian models with the hope of providing a framework for comparison of various systems.
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Microbial media has undergone several changes since its inception but some key challenges remain. In recent years, there has been exploration of several alternative nutrient sources, both to cater to the specificity in requirement of growth of "fussy microorganisms" and also to reduce costs for large-scale fermentation that is required for biotechnology. Our mini-review explores these developments and also points at lacunas in the present areas of exploration, such as a lack of concerted effort in pH and osmolarity regulation. We hope that our commentary provides direction for future research in microbial media.
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Alcohol addiction is a disease that includes a diverse set of phenotypes. Functional alcohol tolerance is an adaptation to the effects of alcohol that restores neuronal homeostatic balance while the drug is present. When the drug is suddenly withheld, these adaptations unbalance the nervous system and are thought to be the origin of some withdrawal symptoms. Withdrawal symptoms, which can be a motivating factor for alcoholics to relapse, are taken as evidence of physiological ethanol dependence. Both tolerance and withdrawal symptoms are diagnostic criteria for alcoholism. Recent studies have demonstrated that the larvae of Drosophila show conserved alcohol tolerance and withdrawal phenotypes indicating that Drosophila genetics can now be used in studying this endophenotype of alcohol addiction.
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Oxidative damage caused by free radicals plays an important role in the causation and progression of many diseases, including aging. Free-radical damage is countered by many mechanisms, including both active antioxidant enzymatic activity in our body and passive antioxidants. Antioxidant response of our body can accommodate increased oxidative damage in diseased states to a level but beyond that level, additional antioxidants are required to combat the increased stress. Apart from the regular dietary sources of antioxidants, many traditional herbal medicines demonstrate a potential to boost antioxidant activity. Rasayana chikitsa that deals with rejuvenation and revitalization is a branch of the Indian traditional medical system of ayurveda. We review some select herbs described in rasayana chikitsa that have been assessed by modern means for stimulating intrinsic antioxidant responses in humans. A critical evaluation of rasayana chikitsa will likely provide urgently needed, actual stimulants of our physiological antioxidant responses and not just more passive antioxidants to add to an already large catalog.