Evaluation of xanthene-appended quinoline hybrids as potential leads against antimalarial drug targets.

A series of fused heterocycle xanthene-appended quinoline 6a-n was successfully synthesized with regioselectivity and characterized using IR, 1H NMR, 13C NMR, and mass spectral data. Molecular docking was performed to find the binding efficacy of all these newly synthesized compounds towards thirteen antimalarial drug targets. Molecular dynamics simulation was carried out to predict the stability of the ligand-bound complex in a solvent medium. Blind and site-directed docking with compounds 6a-n against 13 drug targets revealed most of the ligands to have a good binding affinity with the targets. Analysis on the basis of binding energy, binding modalities of the ligands, intermolecular interactions, and pharmacophore, we identified only one of the ligand-receptor complexes to provide better results. Molecular dynamic simulation of the selected receptor-ligand complex revealed that the synthesized compound had a better binding affinity with the receptor than the native ligand complex. Further analysis of the synthesized ligand in the laboratory may prove promising results in the search for potential antimalarial drugs.

Predictors of Breastfeeding Initiation Among Postnatal Mothers at Tertiary Care Center of a Tribal Dominant State in India: A Regression Analysis.

Background Early initiation of breastfeeding (EIBF) is one of the most important predictors for the survival of a child, spacing between two children, and prevention from childhood infections. Breastfeeding plays an important role in reducing child mortality and morbidity but the practice of EIBF globally is way behind the required time for initiation of breastfeeding after delivery. So, we planned to evaluate the early time of initiation of breastfeeding among the postnatal mothers and to determine the predictors of early initiation of breastfeeding in a tertiary hospital setting. Methodology A hospital-based cross-sectional study was conducted in the postnatal ward of Rajendra Institute of Medical Sciences (RIMS), Ranchi, Jharkhand for a period of three months (March-May 2017). Our study included 200 postnatal mothers who delivered normal and healthy babies. Mother-infant dyads enrolled in our study were interviewed personally during six hours of the postpartum period. Irrespective of the mode of delivery, all babies born during the study period whose mothers consented to be a part of the study were included. Data collected were entered in MS Excel and analyzed using IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp. Results A total of 200 postnatal mothers fulfilling the study criteria were enrolled during the study. Of them, the majority 98 (49%) belonged to the age group 18-25 years. A hundred and twenty-six (63%) of them resided in rural areas, 182 (91%) were housewives, and only 86 (43%) of them had completed secondary education & above. Early initiation of breastfeeding was found to be only 43 (21.5%) among postnatal mothers. Predictors found to be statistically significant with EIBF were mother's residential status [odds ratio (OR): 2.98; 95% confidence interval (CI): 1.25-7.13], educational status of mother (OR: 3.18; 95% CI: 1.12-9.01) mode of delivery of the baby (OR: 8.93; 95% CI: 2.66-30.06) and ante-natal care (ANC) visits (OR: 0.441; 95% CI: 0.311-0.651). Women's age, religion, ethnicity, occupation, type of family, and socioeconomic status displayed no statistically significant relationship with EIBF. Conclusions It is concluded that nearly one-fifth of mothers in the study initiated breastfeeding within one hour of post-delivery. Maternal education, frequent ANC visits, place of residence, and mode of delivery were also associated with EIBF in India. Nursing staff, as well as clinicians, should reinforce the importance of early initiation of breastfeeding by providing proper health education to post-natal beneficiaries.

Alien chromosome segment from Aegilops speltoides and Dasypyrum villosum increases drought tolerance in wheat via profuse and deep root system.

BACKGROUND: Recurrent drought associated with climate change is a major constraint to wheat (Triticum aestivum L.) productivity. This study aimed to (i) quantify the effects of addition/substitution/translocation of chromosome segments from wild relatives of wheat on the root, physiological and yield traits of hexaploid wheat under drought, and (ii) understand the mechanism(s) associated with drought tolerance or susceptibility in wheat-alien chromosome lines. METHODS: A set of 48 wheat-alien chromosome lines (addition/substitution/translocation lines) with Chinese Spring background were used. Seedling root traits were studied on solid agar medium. To understand the influence of drought on the root system of adult plants, these 48 lines were grown in 150-cm columns for 65 d under full irrigation or withholding water for 58 d. To quantify the effect of drought on physiological and yield traits, the 48 lines were grown in pots under full irrigation until anthesis; after that, half of the plants were drought stressed by withholding water for 16 d before recording physiological and yield-associated traits. RESULTS: The alien chromosome lines exhibited altered root architecture and decreased photochemical efficiency and seed yield and its components under drought. The wheat-alien chromosome lines T5DS·5S#3L (TA5088) with a chromosome segment from Aegilops speltoides (5S) and T5DL.5 V#3S (TA5638) with a chromosome segment from Dasypyrum villosum (5 V) were identified as drought tolerant, and the drought tolerance mechanism was associated with a deep, thin and profuse root system. CONCLUSIONS: The two germplasm lines (TA5088 and TA5638) could be used in wheat breeding programs to improve drought tolerance in wheat and understand the underlying molecular genetic mechanisms of root architecture and drought tolerance.

Studies on the effects of LPS, ß-glucan and metabolic inhibitors on the respiratory burst and gene expression in Atlantic salmon macrophages.

Reactive oxygen species (ROS) production in macrophage-like cells is induced as an antimicrobial defence against invading pathogens. In this study, we have explored how different stimuli and metabolic inhibitors affect the level of respiratory burst in Atlantic salmon (Salmo salar L.) head kidney macrophage-like cells. Cells stimulated in vitro by bacterial lipopolysaccharide (LPS) and ß-glucan showed increased production of ROS compared to unstimulated cells. Both stimulation and costimulation by curdlan (ß-glucan) induced a higher production of ROS compared to stimulation and costimulation by LPS. Metabolic inhibitors co-incubated with the stimulants did not, in most cases, perturb the level of ROS generation in the salmon macrophage-like cells. The NAD+ content as well as the NAD+ /NADH ratio increased in curdlan and LPS + curdlan-stimulated cells compared to control cells, which indicated increased metabolic activity in the stimulated cells. Supporting these findings, gene analysis using real-time quantitative PCR showed that arginase-1 and IL-1ß genes were highly expressed in the stimulated cells.

Evaluation of peptide designing strategy against subunit reassociation in mucin 1: A steered molecular dynamics approach.

Subunit reassociation in mucin 1, a breast cancer tumor marker, is reported as one of the critical factors for its cytoplasmic activation. Inhibition of its heterodimeric association would therefore result in loss of its function and alter disease progression. The present study aimed at evaluating peptide inhibitor designing strategies that may serve as antagonist against this receptor-ligand alliance. Several peptides and their derivatives were designed based on native residues, subunit interface, hydrogen bonding and secondary structure. Docking studies with the peptides were carried on the receptor subunit and their binding affinities were evaluated using steered molecular dynamics simulation and umbrella sampling. Our results showed that among all the different classes of peptides evaluated, the receptor based peptide showed the highest binding affinity. This result was concurrent with the experimental observation that the receptor-ligand alliance in mucin 1 is highly specific. Our results also show that peptide ligand against this subunit association is only stabilized through native residue inter-protein interaction irrespective of the peptide structure, peptide length and number of hydrogen bonds. Consistency in binding affinity, pull force and free energy barrier was observed with only the receptor derived peptides which resulted in favorable interprotein interactions at the interface. Several observations were made and discussed which will eventually lead to designing efficient peptide inhibitors against mucin 1 heterodimeric subunit reassociation.

Systematic prioritization of functional hotspot in RIG-1 domains using pattern based conventional molecular dynamic simulation.

BACKGROUND: Retinoic acid inducible gene 1 (RIG-1), multi-domain protein has a role-play in detecting viral nucleic acids and stimulates the antiviral response. Dysfunction of this protein due to mutations makes the route vulnerable to viral diseases. AIM: Identification of functional hotspots that maintains conformational stability in RIG-1 domains. METHODS: In this study, we employed a systematic in silico strategy on RIG-1 protein to understand the mechanism of structural changes upon mutation. We computationally investigated the protein sequence signature for all the three domains of RIG-1 protein that encloses the mutation within the motif. Further, we carried out a structural comparison between RIG-1 domains with their respective distant orthologs which revealed the minimal number of interactions required to maintain its structural fold. This intra-protein network paved the way to infer hotspot residues crucial for the maintenance of the structural architecture and folding pattern. KEY FINDINGS: Our analysis revealed about 40 hotspot residues that determine the folding pattern of the RIG-1 domains. Also, conventional molecular dynamic simulation coupled with essential dynamics provides conformational transitions of hot spot residues among native and mutant structures. Structural variations owing to hotspot residues in mutants again confirm the significance of these residues in structural characterization of RIG-1 domains. We believe our results will help the researchers to better comprehend towards regulatory regions and target-binding sites for therapeutic design within the pattern recognition receptor proteins. SIGNIFICANCE: Our protocol employed in this work describes a novel approach in identifying signature residues that would provide structural insights in protein folding.

Casting the critical regions in nucleotide binding oligomerization domain 2 protein: a signature mediated structural dynamics approach.

Nucleotide binding oligomerization domain 2 (NOD2), a protein involved in the first line defence mechanism has a pivotal role in innate immunity. Impaired function of this protein is implicated in disorders such as Blau syndrome and Crohn's disease. Since an altered function is linked to protein's structure, we framed a systematic strategy to interpret the structure-function relationship of the protein. Initiated with mutation-based pattern prediction and identified a distant ortholog (DO) of NOD2 from which the intra-residue interaction network was elucidated. The network was used to identify hotspots that serve as critical points to maintain the stable architecture of the protein. Structural comparison of NOD2 domains with a DO revealed the minimal number of intra-protein interactions required by the protein to maintain the structural fold. In addition, the conventional molecular dynamics simulation emphasized the conformational transitions at hot spot residues between native NOD2 domains and its respective mutants (G116R, R42W and R54A) structures. The analysis of intra-protein interactions globally and the displacement of residues locally around the mutational site revealed loss of several critical bonds and residues vital for the protein's function. Conclusively we report, about 10 residues in leucine-rich repeat, 13 residues in NOD and 6 residues in CARD domain are required by the NOD2 to maintain its function. This protocol will help the researchers to achieve for more prospective studies to attest druggable site utility in discovering novel drug candidates.

Ab initio coordination chemistry for nickel chelation motifs.

Chelation therapy is one of the most appreciated methods in the treatment of metal induced disease predisposition. Coordination chemistry provides a way to understand metal association in biological structures. In this work we have implemented coordination chemistry to study nickel coordination due to its high impact in industrial usage and thereby health consequences. This paper reports the analysis of nickel coordination from a large dataset of nickel bound structures and sequences. Coordination patterns predicted from the structures are reported in terms of donors, chelate length, coordination number, chelate geometry, structural fold and architecture. The analysis revealed histidine as the most favored residue in nickel coordination. The most common chelates identified were histidine based namely HHH, HDH, HEH and HH spaced at specific intervals. Though a maximum coordination number of 8 was observed, the presence of a single protein donor was noted to be mandatory in nickel coordination. The coordination pattern did not reveal any specific fold, nevertheless we report preferable residue spacing for specific structural architecture. In contrast, the analysis of nickel binding proteins from bacterial and archeal species revealed no common coordination patterns. Nickel binding sequence motifs were noted to be organism specific and protein class specific. As a result we identified about 13 signatures derived from 13 classes of nickel binding proteins. The specifications on nickel coordination presented in this paper will prove beneficial for developing better chelation strategies.

Exploring the structural constraints at cleavage site of mucin 1 isoform through molecular dynamics simulation.

In silico alanine scanning mutagenesis on the cleavable isoform of mucin 1 revealed isoleucine 67 as one of the key factors contributing to the strain at the autoproteolytic cleavage site. In this study, we demonstrate the structural basis of isoleucine-induced rigidity towards the strain-driven autoproteolysis at G(-1)S(+1) cleavage site of mucin 1. We further evaluated the gain in flexibility upon isoleucine 67 mutation through molecular dynamics and essential dynamics studies. The results show that the mutant exhibits stability in its secondary structural elements while the native displays a less-bonded network, however the cleavage site of native remains constrained. Essential dynamics revealed that large motions of the mutant were confined to the loop although the internal domain of the structure remains unaffected. Also, the mutation exerted a larger effect on the intraprotein interactions and consequently resulted in a stabilized motif at the cleavage. Analyses on MD trajectory conformations illustrate a completely disrupted motif in native as an effect of the peptide strain. The study also revealed that in mutant, the cleavage competent catalytic groups C=O and OG were in geometrical aspects unfavorable for a nucleophilic attack. The results support the earlier speculation that the presence of bulky isoleucine proximal G(-1)S(+1) cleavage site limits the conformational sampling of residues and therefore maintains the residues in a torsionally restrained conformation.

Computational investigation of theoretical models of cleavable and uncleavable mucin 1 isoforms.

Mucin 1 is an important tumor marker, and is notable for the autoproteolytic event, a signature of all SEA domain containing proteins. However the isoform MUC1/Y, unlike its closest counterpart MUC1/X, is noted to be uncleavable despite the presence of the catalytic site. Sequence analysis has revealed the presence of an 18 residue segment spliced out from MUC1/Y marking the only difference between uncleavable MUC1/Y and cleavable MUC1/X mucin 1 isoforms. This work was aimed at studying in silico, the structural and functional significance of the 18 residue insert in the cleavage process. 3-Dimensional structures of the isoforms were predicted using a combined threading and ab initio method followed by mutation and normal mode analysis. Our analysis revealed both isoforms to poses an intact SEA domain, nevertheless, an altered functional scaffold around the cleavage site was noted between the structures. Mutation analysis by alanine substitutions at the insert region revealed Ile67 to be more destabilizing, resulting in increased fluctuation of the neighboring residues. Predicted molecular motions of the protein indicated localized motions in the native, rather than the mutated model. Intramolecular interactions between the native and I67A structures showed wide variations in main chain and side chain interactions. Furthermore, the findings suggest the neighboring residues, in particular Ile67 contribute more to the structural and functional properties of the protein and hence it is predicted to be one of the crucial residues for the cleavable nature of MUC1/X.

Coexistence of rhinoscleroma with Rosai-Dorfman disease: is rhinoscleroma a cause of this disease?

INTRODUCTION: Rhinoscleroma and Rosai-Dorfman disease have been reported to coexist in the same patient at different sites. Rosai-Dorfman disease may have an aetiological relationship with rhinoscleroma, although this has not yet been proved. CASE REPORT: A case of a 42-year-old woman with recurrent nasal masses is presented, with histopathological proof of both conditions coexisting in the same nasal lesion. DISCUSSION: The aetiopathology, clinical features and treatment of both diseases are discussed and a literature survey is reported. Histologically, the presence of Mikulicz cells with entrapped, rod-like, Gram-negative bacilli and Russell bodies suggests rhinoscleroma. Emperipolesis and S-100-positive histiocytes confirm the diagnosis of Rosai-Dorfman disease. The presence of both in the same slides from affected tissues has never been demonstrated before. In the light of this evidence, the author believes that rhinoscleroma must be considered in the aetiology of Rosai-Dorfman disease.

3,4-Dimeth-oxy-benzaldehyde [2,8-bis-(trifluoro-meth-yl)quinolin-4-yl]hydrazone.

In the title compound, C(20)H(15)F(6)N(3)O(2), the quinoline ring system is almost coplanar with the benzene ring; the dihedral angle between the two planes is 2.31 (8)°. The crystal structure displays an inter-molecular C-H⋯F hydrogen bond. In addition, a weak π-π inter-action is observed between the unfused benzene ring and the benzene ring of quinoline, with a centroid-centroid distance of 3.586 (1) Å.

Dietary beta-1,3 glucan potentiates innate immunity and disease resistance of Asian catfish, Clarias batrachus (L.).

This study investigated the effects of short and prolonged administration of a yeast beta-glucan on non-specific immune parameters, growth rate and the disease resistance of Asian catfish, Clarias batrachus. Fish fed with a basal diet (control) and test diet (basal diet supplemented with 0.1% glucan) for 1, 2 and 3 weeks were assayed for superoxide production, serum myeloperoxidase (MPO) content, natural haemagglutinin level, complement and lysozyme activities. Fish were weighed at weekly intervals and specific growth rate (SGR, % increase in body weight per day) was determined. After each week, fish were challenged with Aeromonas hydrophila to measure the level of protection. Results showed that glucan administration at 0.1% in feed, significantly (P<0.05) enhanced MPO and lysozyme levels, superoxide production, haemagglutination titre and level of protection against A. hydrophila challenge, irrespective of length of exposure. The alternative complement activity and SGR were not affected by the dietary supplementation of yeast glucan. As glucan feeding at 0.1% for 1 week is able to enhance the non-specific immunity and disease resistance of catfish efficiently, short-term feeding might be used in farmed catfish diets to enhance disease resistance.

Neutrophil and monocyte adhesion molecules in bronchopulmonary dysplasia, and effects of corticosteroids.

AIMS: To study a longitudinal change in the expression of adhesion molecules CD11b, CD18, and CD62L on neutrophils and monocytes in very low birth weight babies who develop respiratory distress syndrome, to compare these levels between bronchopulmonary dysplasia (BPD) and non-BPD infants, and to assess the effect of corticosteroid treatment on these adhesion molecules. METHODS: Of 40 eligible neonates, 11 neonates were oxygen dependent at 36 weeks (BPD 36 weeks), 16 infants were oxygen dependent at 28 days, but not at 36 weeks (BPD d28), and 13 infants did not develop BPD. Seventeen neonates received a six day course of steroid treatment. Expression of CD11b, CD18, and CD62L was measured on neutrophils and monocytes in arterial blood on days 1, 3, 7, 14, 21, and 28, and before and 2-3 days after initiation of dexamethasone treatment by flow cytometry. RESULTS: CD18 expression on neutrophils and monocytes and CD62L on neutrophils, measured as mean fluorescent intensity, was significantly decreased in BPD neonates compared to non-BPD neonates on days 1-28. Dexamethasone treatment significantly decreased CD11b, CD18, and CD62L expression on neutrophils, and CD11b and CD18L expression on monocytes. CONCLUSIONS: Decreased CD18 expression on neutrophils and monocytes, and decreased CD62L expression on neutrophils, measured as mean fluorescent intensity during the first four weeks of life in micropremies may be risk factors and early predictors of BPD. Dexamethasone use was associated with decreased expression of CD11b, CD18, and CD62L.

Respiratory burst activity in bronchopulmonary dysplasia and changes with dexamethasone.

The first objective of this study was to evaluate longitudinal changes in respiratory burst activity in circulating neutrophils and monocytes in infants of less than 30 weeks of gestation with respiratory distress syndrome (RDS), and to examine differences in neonates who subsequently developed bronchopulmonary dysplasia (BPD) compared with those neonates who did not. The second objective was to investigate the effects of dexamethasone on respiratory burst activity in neutrophils and monocytes. We measured burst activity on neutrophils and monocytes in fresh heparinized blood in response to E. coli, N-formyl-met-leu-phe (fMLP), and phorbol 12-myristate 13-acetate stimulation on days 3, 7, 14, and 21 of life, before and 2-3 days after initiating a 6-day course of dexamethasone treatment. Infants with RDS participating in the study were followed until discharge, and were classified as non-BPD and either 1) BPD d28, reflecting their oxygen requirement at day of life 28, or 2) BPD 36 weeks, reflecting oxygen dependence at 36 weeks' corrected gestational age. The diagnosis of BPD was supported by radiological changes of BPD. The percentage of activated neutrophils producing a respiratory burst increased in all premature infants with increasing postnatal days during the first 28 days of life, when the physiological stimulus E. coli was used as an activator (P < 0.02). There was no significant difference in respiratory burst activity measured either as percent activation or as mean fluorescence intensity between non-BPD and BPD infants after adjusting for the difference in weight and gestational age between the two groups. The treatment of premature infants with dexamethasone was associated with decreased activation of neutrophils (P < 0.005) when E. coli was used as a stimulus. In conclusion, a significant increase in neutrophil respiratory burst activity occurs during the first month of life in very low birth weight infants. Greater pulmonary damage in BPD cannot be attributed to reduced burst activity in either neutrophils or monocytes. Dexamethasone treatment was associated with decreased neutrophil respiratory burst activity.

Pharmacokinetics of betamethasone in twin and singleton pregnancy.

OBJECTIVE: The aims of the study were to compare the pharmacokinetics of betamethasone in singleton pregnancy with the pharmacokinetics in twin pregnancy and to assess the adrenal suppression produced by betamethasone. STUDY DESIGN: We measured serial betamethasone and cortisol levels in 30 singleton and 21 twin pregnancies after the first dose of betamethasone and calculated the pharmacokinetic parameters for betamethasone including volume of distribution, half-life, and clearance. We also measured cord and maternal blood levels of betamethasone at the birth of infants of 13 singleton and 9 twin pregnancies. RESULTS: The half-life of betamethasone in mothers with twin pregnancies was significantly shorter than that in mothers with singleton pregnancies (7.2 +/-2.4 versus 9.0 +/- 2.7 hours; P <.017). Clearance of betamethasone in the twin pregnancies appeared greater than in singleton pregnancies (8.4 +/- 6.4 versus 5.7+/- 3.1 L/h; P =.06) but did not reach statistical significance. Volume of distribution was similar in the two groups. Because the time between the last dose of betamethasone and birth varied widely (range, 2-158 hours), mothers with a longer interval after treatment tended to have a higher cord-to-maternal betamethasone ratio than did mothers with a shorter interval in both twin and singleton pregnancies. This finding indicated delayed fetal clearance, but the correlation was weak (R (2) = 0.29 for twins and 0.08 for singletons). CONCLUSION: The shorter half-life of betamethasone in twin pregnancy than in singleton pregnancy may cause the level of betamethasone to be subtherapeutic for lung maturation in twin pregnancy.

ABO segregation distortion in Visakhapatnam, India.

Distortions in mother-infant, mother-child and father-child segregation for the ABO system as well as in the sex of offspring are described in a sample from a maternity service and from families of Visakhapatnam, India. Some distortions follow the expected fetomaternal incompatibility depression, others the expected feto-maternal induction of tolerance, and some remain unexplained. A differential action of selective factors on male and female fetuses, infants and children was also found, but no hypothesis could be postulated to explain it. The mother-infant matrix was found to be different from the mother-child matrix probably due to the inclusion of the reproductive time only in the mother-infant matrix. Unexpectedly, father-child segregation distortions were also found.