Ways to determine reliability in the operation of ship parts made by banding method

In the development of modern shipbuilding conditions and the repair of ship units, a special role is given to the use of basic structural elements consisting of technological parts. When performing these steps, it is important to analyze the properties of the materials from which the technological components of ship equipment are made. Testing should be close to the operating conditions of ship axles and shafts, namely cyclic loading, aggressive and adhesive environment. Therefore, a special factor is the technological control over the sequence of manufacture, selection of materials, surfacing technology. All these requirements can be analyzed and predicted using computer modulation. Investigations of the properties of the transition layers of the weld and the base metal and their effect on the number of load cycles in the tests are also key. All conditions will be met with the optimal selection of the chemical component Ni - Cr, which provide the required level of doping. The hardness of the materials is ensured by the presence of Mg in the metal. Also important are the heat treatment modes that provide the desired final structure of the material for machining and surfacing. For this part and its elements, the best properties in terms of operation in fine austenitic and pearlitic structures. During the operation of ship shafts and axles, the propagation of puncture loads is performed due to the occurrence of final stresses at low-cycle and multi-cycle loads and subsequent fatigue of the structural lattice. When considering the range of materials used in combined structures is very large and includes most welded steels. According to the combination of materials in one unit, it is advisable to distinguish two main groups of structures: with welded joints of steels of the same structural class, but different alloying, and with welded joints of steels of different structural classes. In this regard, the decision to obtain a balanced bandage connection lies in obtaining a fine-grained structure of the weld metal and the seam area.

The aphid BCR4 structure and activity uncover a new defensin peptide superfamily

Aphids (Hemiptera: Aphidoidea) are among the most injuring insects for agricultural plants and their management is a great challenge in agronomical research. A new class of proteins, called Bacteriocyte-specific Cysteine-Rich (BCR), provides an alternative to chemical insecticides for pest control. BCRs have been initially identified in the pea aphid Acyrthosiphon pisum. They are small disulfide bond-rich proteins expressed exclusively in aphid bacteriocytes, the insect derived cells that host intracellular symbiotic bacteria. Here, we show that one out of the A. pisum BCRs, BCR4, displays an outstanding insecticidal activity against the pea aphid, impairing insect survival and nymphal growth, providing evidence for its potential use as a new biopesticides. Our comparative genomics and phylogenetic analysis indicate that BCRs seem restricted to the aphid lineage. The 3D structure of the BCR4 reveals that this peptide belongs to a yet unknown structural class of peptides and defines a new superfamily of defensins.

Exposure assessment using biomonitoring

Complex studies were performed combining macroscopic and biochemical analyzes of selected biomonitors, exposed in exposure systems outdoor with mixtures of pollutants as well as controlled exposure with certain concentrations of pollutants in fumigation chambers. In this study, the following plant species were used as bioindicators: Nicotiana tabacum, Petunia hybrida, Ricinus comunis, Trifolium pretense. The exposure plant samples were compared with control samples of biomonitors maintained under standardized conditions in the climate chamber. Classical methods of biochemistry combined with those of exposure biomonitoring have led to the completion of knowledge about the ways of action of plants to pollution. The analysis of some of the antioxidant compounds that are representing a structural class of chemicals (enzymes) with a wide range of biological functions, with the role of free radical inhibition, was performed. Many of the constituent compounds in certain cell types, also called active compounds, in this case, polyphenols are present in the body of some plant species. Polyphenol's presence in organisms, that are not usually present or are in normal quantities, is caused by stress, (pollution being a stress factor). Large amounts of polyphenols in plants are also given by the presence of pollutants in the environment. Through these extensive combined studies, it has been demonstrated that pollution can be a degenerative factor at the biochemical and physiological level, at the plant tissue level, with irreversible effects.

The structural repertoire of Fusarium oxysporum f. sp. lycopersici effectors revealed by experimental and computational studies

Plant pathogens secrete proteins, known as effectors, that function in the apoplast and inside plant cells to promote virulence. Effectors can also be detected by cell-surface and cytosolic receptors, resulting in the activation of defence pathways and plant immunity. Our understanding of fungal effector function and detection by immunity receptors is limited largely due to high sequence diversity and lack of identifiable sequence motifs precluding prediction of structure or function. Recent studies have demonstrated that fungal effectors can be grouped into structural classes despite significant sequence variation. Using protein x-ray crystallography, we identify a new structural class of effectors hidden within the secreted in xylem (SIX) effectors from Fusarium oxysporum f. sp. lycopersici (Fol). The recognised effectors Avr1 (SIX4) and Avr3 (SIX1) represent the founding members of the Fol dual-domain (FOLD) effector class. Using AlphaFold ab initio protein structure prediction, benchmarked against the experimentally determined structures, we demonstrate SIX6 and SIX13 are FOLD effectors. We show that the conserved N-domain of Avr1 and Avr3 is sufficient for recognition by their corresponding, but structurally-distinct, immunity receptors. Additional structural prediction and comparison indicate that 11 of the 14 SIX effectors group into four structural families. This revealed that genetically linked effectors are related structurally, and we provide direct evidence for a physical association between one divergently-transcribed effector pair. Collectively, these data indicate that Fol secretes groups of structurally-related molecules during plant infection, an observation that has broad implications for our understanding of pathogen virulence and the engineering of plant immunity receptors.

Deep-Sea Anemones Are Prospective Source of New Antimicrobial and Cytotoxic Compounds

The peculiarities of the survival and adaptation of deep-sea organisms raise interest in the study of their metabolites as promising drugs. In this work, the hemolytic, cytotoxic, antimicrobial, and enzyme-inhibitory activities of tentacle extracts from five species of sea anemones (Cnidaria, orders Actiniaria and Corallimorpharia) collected near the Kuril and Commander Islands of the Far East of Russia were evaluated for the first time. The extracts of Liponema brevicorne and Actinostola callosa demonstrated maximal hemolytic activity, while high cytotoxic activity against murine splenocytes and Ehrlich carcinoma cells was found in the extract of Actinostola faeculenta. The extracts of Corallimorphus cf. pilatus demonstrated the greatest activity against Ehrlich carcinoma cells but were not toxic to mouse spleen cells. Sea anemones C. cf. pilatus and Stomphia coccinea are promising sources of antimicrobial and antifungal compounds, being active against Gram-positive bacteria Bacillus subtilis, Staphylococcus aureus, and yeast Candida albicans. Moreover, all sea anemones contain α-galactosidase inhibitors. Peptide mass fingerprinting of L. brevicorne and C. cf. pilatus extracts provided a wide range of peptides, predominantly with molecular masses of 4000–5900 Da, which may belong to a known or new structural class of toxins. The obtained data allow concluding that deep-sea anemones are a promising source of compounds for drug discovery.

Seleno-amino acids: A novel class of anti-tuberculosis compounds identified through modified culture screening conditions

<p>Tuberculosis continues to be a major world health problem, causing more deaths than any other bacterial disease. Long treatment durations using a complex cocktail of drugs are often associated with patient non-adherence to therapy, and this has accelerated the development of drug resistant strains. Tuberculosis drug resistance has developed to the extent that some strains are resistant to all clinically used drugs. Therefore novel tuberculosis treatment drugs are urgently required to combat these resistant strains, sterilise latent infections and reduce lengthy treatment durations. This research developed and optimised a high-throughput assay to screen chemical libraries for compounds with anti-mycobacterial activity. The assay utilised fast growing tuberculosis model species M. smegmatis expressing foreign green fluorescent protein (GFP). GFP allowed bacterial growth inhibition to be measured both by fluorescence in addition to absorbance. The assay was expanded to four different culture conditions two of which were nutrient starvation that better mimicked environmental conditions M. tuberculosis is exposed to during infection. These differential culture conditions also revealed previously unidentified mycobacterial inhibitors. Three chemical libraries totaling over 5,000 compounds were screened in the different culture conditions. Seleno-amino acids (Se-AAs), a novel class of anti-tuberculosis compounds, were discovered through screens in nutrient starvation conditions. Based on traits of strong inhibitory activity towards mycobacteria, low human cell line cytotoxicity, structural novelty and known over-the-counter sale as a non-prescription dietary supplement, the Se-AAs were chosen as a promising pharmacophore for further study. Using evidence derived from anti-sense gene knockdown, transposon mutagenesis and biochemical enzyme assays, a pro-drug hypothesis of anti-mycobacterial activity was proposed that involved Se-AAs being transported into the mycobacterial cell by nutrient uptake transporters and subsequent cleavage into catalytically active methylselenium species by lyase enzymes used in mycobacterial sulphurous amino acid metabolism. The activated methylselenium is reduced by mycobacterial redox homeostasis enzymes involved in mycobacterial oxidative defence such as alkyl hydroperoxidases, generating reactive oxygen radical products that damage mycobacterial DNA, lipids and proteins. Reduced methylselenol can be cycled back to the oxidised state by cellular mycothiones, continuously generating damaging reactive oxygen species within the mycobacterial cell. Methylselenium species also disrupt essential mycobacterial processes, such as ketosteroid catabolism and iron-sulphur cluster protein function. In summary, this research has designed and implemented a novel dual label differential culture condition assay useful in the screening and detection of chemicals with anti-tuberculosis properties. A novel structural class of anti-tuberculosis compounds with therapeutic potential, the Se-AAs, was discovered using this assay, the structure-activity relationship of the Se-AAs was explored and a three-component model of Se-AA anti-tuberculosis activity is proposed.</p>

Seleno-amino acids: A novel class of anti-tuberculosis compounds identified through modified culture screening conditions

<p>Tuberculosis continues to be a major world health problem, causing more deaths than any other bacterial disease. Long treatment durations using a complex cocktail of drugs are often associated with patient non-adherence to therapy, and this has accelerated the development of drug resistant strains. Tuberculosis drug resistance has developed to the extent that some strains are resistant to all clinically used drugs. Therefore novel tuberculosis treatment drugs are urgently required to combat these resistant strains, sterilise latent infections and reduce lengthy treatment durations. This research developed and optimised a high-throughput assay to screen chemical libraries for compounds with anti-mycobacterial activity. The assay utilised fast growing tuberculosis model species M. smegmatis expressing foreign green fluorescent protein (GFP). GFP allowed bacterial growth inhibition to be measured both by fluorescence in addition to absorbance. The assay was expanded to four different culture conditions two of which were nutrient starvation that better mimicked environmental conditions M. tuberculosis is exposed to during infection. These differential culture conditions also revealed previously unidentified mycobacterial inhibitors. Three chemical libraries totaling over 5,000 compounds were screened in the different culture conditions. Seleno-amino acids (Se-AAs), a novel class of anti-tuberculosis compounds, were discovered through screens in nutrient starvation conditions. Based on traits of strong inhibitory activity towards mycobacteria, low human cell line cytotoxicity, structural novelty and known over-the-counter sale as a non-prescription dietary supplement, the Se-AAs were chosen as a promising pharmacophore for further study. Using evidence derived from anti-sense gene knockdown, transposon mutagenesis and biochemical enzyme assays, a pro-drug hypothesis of anti-mycobacterial activity was proposed that involved Se-AAs being transported into the mycobacterial cell by nutrient uptake transporters and subsequent cleavage into catalytically active methylselenium species by lyase enzymes used in mycobacterial sulphurous amino acid metabolism. The activated methylselenium is reduced by mycobacterial redox homeostasis enzymes involved in mycobacterial oxidative defence such as alkyl hydroperoxidases, generating reactive oxygen radical products that damage mycobacterial DNA, lipids and proteins. Reduced methylselenol can be cycled back to the oxidised state by cellular mycothiones, continuously generating damaging reactive oxygen species within the mycobacterial cell. Methylselenium species also disrupt essential mycobacterial processes, such as ketosteroid catabolism and iron-sulphur cluster protein function. In summary, this research has designed and implemented a novel dual label differential culture condition assay useful in the screening and detection of chemicals with anti-tuberculosis properties. A novel structural class of anti-tuberculosis compounds with therapeutic potential, the Se-AAs, was discovered using this assay, the structure-activity relationship of the Se-AAs was explored and a three-component model of Se-AA anti-tuberculosis activity is proposed.</p>

Q3 Accuracy and SOV Measure Analysis of Application of GA in Protein Secondary Structure Prediction

The protein secondary structure prediction (PSP) of the large biological molecule protein is an important task of bioinformatics and in the last decades many machines learning and soft computing methodologies play vital roles in achieving satisfactory results. The protein structural class determination is an important topic in protein science because an idea about protein structural class is quite useful to know about the changes and reaction of a living body in order to design new drugs and medicines. Though several hard computing techniques may be helpful in these areas but focusing upon the steady development and big data size in protein sequences that are entering into databanks, it is a challenge to do experiments with the hard computing techniques. Soft computing techniques like Artificial Neural Network, Fuzzy logic, Genetic Algorithm play a vital role for these types of genomic researches. To face these complex challenges, this article presents a novel method to predict the protein structure by using Genetic Algorithm. The Q3 accuracy and SOV measure analysis with SOVH, SOVE, SOVC value of respective α-helix (H), β-sheet (E) and coil/loop(C) structures are also discussed. The application of Genetic algorithm i.e. the proposed technique GApred provides better result than that of SPIDER2, JPred4, FSVM and SSpro5 for all the three datasets in the experiment. This method is helpful for distinct protein secondary structure prediction and a significant success rate was observed, which indicates that it can be used as a powerful tool in drug design and medicine research.

Nutrition phytochemicals affecting platelet signaling and responsiveness: implications for thrombosis and hemostasis

Cardiovascular disease, in particular due to arterial thrombosis, is a leading cause of mortality and morbidity, with crucial roles of platelets in thrombus formation. For multiple plant-derived phytochemicals found in common dietary components, claims have been made regarding cardiovascular health and antiplatelet activities. Here we present a systematic overview of the published effects of common phytochemicals, applied in vitro or in nutritional intervention studies, on agonist-induced platelet activation properties and platelet signaling pathways. Comparing the phytochemical effects per structural class, we included general phenols: curcuminoids (e.g., curcumin), lignans (honokiol, silybin), phenolic acids (caffeic and chlorogenic acid), derivatives of these (shikimic acid) and stilbenoids (isorhapontigenin, resveratrol). Furthermore, we evaluated the flavonoid polyphenols, including anthocyanidins (delphinidin, malvidin), flavan-3-ols (catechins), flavanones (hesperidin), flavones (apigenin, nobiletin), flavonols (kaempferol, myricetin, quercetin), isoflavones (daidzein, genistein); and terpenoids including carotenes and limonene; and finally miscellaneous compounds like betalains, indoles, organosulfides (diallyl trisulfide) and phytosterols. We furthermore discuss the implications for selected phytochemicals to interfere in thrombosis and hemostasis, indicating their possible clinical relevance. Lastly, we provide guidance on which compounds are of interest for further platelet-related research.

Natural Products and Their Derivatives against Human Herpesvirus Infection

Herpesviruses establish long-term latent infection for the life of the host and are known to cause numerous diseases. The prevalence of viral infection is significantly increased and causes a worldwide challenge in terms of health issues due to drug resistance. Prolonged treatment with conventional antiviral drugs is more likely to develop drug-resistant strains due to mutations of thymidine nucleoside kinase or DNA polymerase. Hence, the development of alternative treatments is clearly required. Natural products and their derivatives have played a significant role in treating herpesvirus infection rather than nucleoside analogs in drug-resistant strains with minimal undesirable effects and different mechanisms of action. Numerous plants, animals, fungi, and bacteria-derived compounds have been proved to be efficient and safe for treating human herpesvirus infection. This review covers the natural antiherpetic agents with the chemical structural class of alkaloids, flavonoids, terpenoids, polyphenols, anthraquinones, anthracyclines, and miscellaneous compounds, and their antiviral mechanisms have been summarized. This review would be helpful to get a better grasp of anti-herpesvirus activity of natural products and their derivatives, and to evaluate the feasibility of natural compounds as an alternative therapy against herpesvirus infections in humans.