345 research outputs found

    Mitochondrial Molecular Adaptations and Life History Strategies Coevolve in Plants

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    Messenger RNA secondary structure prevents mutations at functionally important sites. Mutations at exposed sites would cause micro-adaptations, niche-specialization, and therefore, can be thought to promote K-strategists. Exposing, rather than protecting, conserved sites, is also potentially adaptive because they probably promote macro-adaptive changes. This presumably fits r-strategists: their population dynamics tolerate decreased survival. We found that helix-forming tendencies are greater at evolutionary conserved sites of plant mitochondrial mRNAs than at evolutionary variable sites in a majority (73%) of species–gene combinations. K-strategists preferentially protect conserved sites in short genes, r-strategists protect them most in larger genes. This adaptive scenario resembles our earlier findings in chloroplast genes. Protection levels at various codon positions also display disparity with respect to life history strategies of the plants. Conserved site protection increases overall mRNA folding stabilities for some genes, while decreases it for some others. This contrast exists between homologous genes of r- and K- strategists. Such compensating interactions between variability, mRNA size, codon position, and secondary structure factors within r- and K-strategists are most likely, molecular adaptations of plants belonging to the two extreme life history strategies. Our results suggest coevolution between molecular and ecological adaptive strategies

    Phylogenetic influence of complex, evolutionary models: a Bayesian approach

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    Molecular evolution recovers the history of living species by comparing genetic information, exploring genome structure and function from an evolutionary perspective. Here we infer substitution rates and ancestral reconstructions, to better understand mutation responses to some known biochemical phenomena. Mutation processes are commonly inferred using parsimony, maximum likelihood and Bayesian. Parsimony is not explicitly model-based, and is statistically biased due to unrealistic assumptions. The model-based maximum likelihood approaches become computationally inefficient while analyzing large or high-dimensional datasets, leaving little opportunities to incorporate complex evolutionary models. We implemented a posterior probability (Bayesian) approach that evaluates evolutionary models, applying it to primate mitochondrial genomes. The species nucleotide sequence data were augmented with ancestral states at the internal nodes of the phylogeny. We simplified probability calculations for substitution events along the branches by assuming that only up to one or two substitution events occurred per branch per site. These conditional pathway calculations introduce very little bias into the inferred reconstructions, while increasing the feasibility of incorporating complex evolutionary models with higher dimensions. Compositional bias tests, including functional predictions of ancestral tRNAs, show that ancestral sequences from the Bayesian approach are more biologically realistic than those reconstructed by maximum likelihood. To explore other model complexity, we allowed substitution rates to vary among sites by having a different model at each site. With a strand-symmetric model as the base model, asymmetric substitution probabilities for specific substitution types were varied among sites. This model would not be feasible with standard matrix exponentiation methods, particularly maximum likelihood. We observed for A--\u3eG and C--\u3eT substitutions almost linear, respectively, almost asymptotic responses (with some regional deviations). Note that the HMM models had no a priori response built in them. Observed responses fitted predictions from earlier gene by gene likelihood analyses. For A--\u3eG substitutions, deviations from the expected linear response correlated positively with the loop-forming propensity of the corresponding site in the mRNA secondary structure. In the COI region, C--\u3eT substitutions have a prominent dip, suggesting protection against mutations. The C--\u3eT substitution responses differed significantly between primate sub-groups defined based on their single genome A--\u3eG responses

    Mechanical and durability aspects of concrete incorporating secondary aluminium slag

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    The environmental impact can be minimised by making use of many industrial wastes in a sustainable manner. Recycling and reutilisation of industrial waste and by-products is of paramount importance in cement and concrete industry. In view of rapid infrastructure growth, there is an emerging need for development of cementitious materials or fillers either to replace cement or fine aggregate for stable growth. One of the industrial wastes is secondary aluminium dross. In this paper, an attempt has been made to study the mechanical and durability aspects of concrete incorporated with secondary aluminium dross. Cement has been partially replaced by secondary aluminium dross in different proportions to study the mechanical and durability aspects. Various properties such as compressive strength, split tensile strength, flexural strength, sorptivity, water absorption, rapid chloride penetration have been studied for the usefulness of secondary aluminium dross as construction material. It is observed that up to 15% replacement of cement by secondary aluminium dross, the responses are comparable with the conventional concrete. Studies have also been carried out by adding other supplementary cementitious materials such as fly ash and silica fume in various proportions along with secondary aluminium dross and found the improved mechanical and durability properties. From the overall study, it can be concluded that the concrete incorporated with secondary aluminium dross can be used for making paver blocks, refractory bricks and for normal concrete strength applications

    A Framework to Reversible Data Hiding Using Histogram-Modification

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    A Novel method of Stegnography to achieve Reversible Data Hiding (RDH) is proposed using Histogram Modification (HM). In this paper the HM technique is revisited and a general framework to construct HM-based RDH is presented by simply designing the shifting and embedding functions on the cover image. The Secret Image is embedded inside the cover image using several steps of specific shifting of pixels with an order. The secret image or logo is retrieved without any loss in data on the cover and as well as in the secrete image. The Experimental results show the better Peak Signal to Noise Ratio (PSNR) with the existing methods

    Effect of fertilizer carbamide on proteolytic enzymes of fish Labeo rohita

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    Specific activities of acid, alkaline and neutral proteases in liver, muscle, brain, and gill of fish exposed to 50 ppm ambient carbamide for 15, 30 and 60 days and in control were estimated. It was observed that carbamide even at low concentration of 50 ppm inhibited proteolysis and favoured protein synthesis

    Fine needle aspiration: a simple and handy tool to diagnose malignant lymphadenopathy

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    Background: Fine needle aspiration cytology (FNAC) of the lymph node is a simple useful screening test to diagnose suspected and unsuspected secondary and primary lymph node malignancy. The aim of the present study is to know the role of FNAC in the diagnosis of clinically suspected and unsuspected lymph node malignancies. Study design: prospective cohort study.Methods: Study material comprise of ‘76’ lymph nodes aspirates reported as malignant on cytology, out of total 445 cases of lymph node aspiration in two years period i.e. from October 2014 to September 2016.These 76 smears were studied and tabulated according to their cytomorphology and the lymph node group affected was noted. The clinical and radiological data were also noted.Results: Males were found more affected than females. cervical lymph node is the commonest group involved. Metastasis from squamous cell carcinoma was the most common diagnosis made on cytology.Conclusions: FNAC is found simple and very useful tool for diagnosing malignant lesions of lymph nodes especially in case of metastasis

    EVALUATION OF DIFFERENT CULTURE MEDIA FOR ENHANCED PRODUCTION OF PSEUDOMONAS AERUGINOSA (MTCC NO 2453) BIOMASS AND ITS PROTEINS

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    Objective: Microorganisms, especially bacteria and its proteins have proven to be potential anti-cancer agents as they selectively attack the tumor cells or tumor micro-environments. The extract of Pseudomonas aeruginosa found to contain proteins that have shown promising anticancer activity. In this work, it was attempted to increase the biomass and trigger the total protein fraction of Pseudomonas aeruginosa (MTCC 2453).Methods: The organism was cultivated in three different such as Luria-Bertani (LB) broth, minimal medium9 (M9), super broth medium (SB) and asparagine-proline (AP) broth. Asparagine proline broth was selected as it has shown high cell growth rate. The media was further optimized by the addition of NaHCO3 and copper sulphate to trigger the protein production. Optimized Aspergine proline broth has achieved highest cell biomass. After the shake flask culture, the overnight grown culture in optimized AP medium was further grown in a 5 L bioreactor by fed-batch cultivation to achieve higher cell densities.Results: The highest protein production was achieved at 40 ° C. Highest biomass and protein content was observed at pH 8 while lowest biomass was produced at pH 2. A gradual increase in biomass content observed from 12 h towards to 48 h.Conclusion: High biomass and proteins content and of Pseudomonas aeruginosa (MTCC 2453) can be produced in optimized asparagine-proline broth. Further the extract is purified to produce novel anti-cancer proteins

    ACTH Secreting Pituitary Microadenoma Presenting with Acute Psychosis, Delirium and Paroxysmal Sympathetic Hyperactivity

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    ACTH secreting pituitary adenomas are known to be associated with behavioral changes but acute presentation including psychosis and delirium are less common. We report the case of a 42-year-old lady with a known medical history of hypertension and diabetes mellitus, presenting with acute onset behavioral changes suggestive of psychosis. Further evaluation revealed an ACTH dependent Cushing’s disease with a pituitary microadenoma. The patient was admitted for endoscopic resection of the adenoma. During the peri-operative period, she experienced worsening of psychosis along with delirium. She also developed episodes of unresponsiveness, posturing, severe diaphoresis and dyspnea accompanied by tachycardia and hypertension which were managed with Midazolam and Levetiracetam. A seizure work-up and CT brain were unremarkable. At follow-up, she showed full resolution of symptoms with good blood pressure and glycemic control. ACTH secreting pituitary microadenoma presenting with acute psychosis, delirium and paroxysmal sympathetic hyperactivity. Keywords: Cushing’s disease, neuropsychiatric, dysautonomia

    Relationship between mRNA secondary structure and sequence variability in Chloroplast genes: possible life history implications

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    <p>Abstract</p> <p>Background</p> <p>Synonymous sites are freer to vary because of redundancy in genetic code. Messenger RNA secondary structure restricts this freedom, as revealed by previous findings in mitochondrial genes that mutations at third codon position nucleotides in helices are more selected against than those in loops. This motivated us to explore the constraints imposed by mRNA secondary structure on evolutionary variability at all codon positions in general, in chloroplast systems.</p> <p>Results</p> <p>We found that the evolutionary variability and intrinsic secondary structure stability of these sequences share an inverse relationship. Simulations of most likely single nucleotide evolution in <it>Psilotum nudum </it>and <it>Nephroselmis olivacea </it>mRNAs, indicate that helix-forming propensities of mutated mRNAs are greater than those of the natural mRNAs for short sequences and vice-versa for long sequences. Moreover, helix-forming propensity estimated by the percentage of total mRNA in helices increases gradually with mRNA length, saturating beyond 1000 nucleotides. Protection levels of functionally important sites vary across plants and proteins: <it>r</it>-strategists minimize mutation costs in large genes; <it>K</it>-strategists do the opposite.</p> <p>Conclusion</p> <p>Mrna length presumably predisposes shorter mRNAs to evolve under different constraints than longer mRNAs. The positive correlation between secondary structure protection and functional importance of sites suggests that some sites might be conserved due to packing-protection constraints at the nucleic acid level in addition to protein level constraints. Consequently, nucleic acid secondary structure <it>a priori </it>biases mutations. The converse (exposure of conserved sites) apparently occurs in a smaller number of cases, indicating a different evolutionary adaptive strategy in these plants. The differences between the protection levels of functionally important sites for <it>r</it>- and <it>K-</it>strategists reflect their respective molecular adaptive strategies. These converge with increasing domestication levels of <it>K</it>-strategists, perhaps because domestication increases reproductive output.</p
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