Genetic Diversity and Anti-Oxidative Potential of Streptomyces spp. Isolated from Unexplored Niches of Meghalaya, India.

Streptomyces is genetically and functionally diverse genus known to produce a wide array of phenolics and flavonoids with significant biotechnological applications. 52 isolates belonging to 26 species of Streptomyces collected from Meghalaya, India were analyzed for their genetic diversity using BOX-PCR. Significant inter- and intra- generic diversity was observed among the Streptomyces isolates especially those belonging to S. cacaoi, S. lavendulae, S. olivochromogenes, S. aureus, S. flavovirens. During bioactivity screening of the isolates, S. rectiviolaceus MJM72 recorded the highest DPPH activity (77.13 ± 0.91%) whereas S. antimycoticus MSCA162 showed excellent ABTS radical scavenging activity (99.65 ± 0.41%). On the other hand, S. novaecaesareae MJM58 had the highest (756.4 ± 7.38 µg GAE g-1 fresh weight) phenolic content while S. rectiviolaceus MJM72 was recorded with the highest flavonoid content (69.3 ± 0.12 µg QE g-1 fresh weight). As compared to total flavonoid content, total phenolic content had a stronger correlation with antioxidant activities. HPLC analysis of five selected isolates showed presence of gallic acid and pyrocatechol as predominant phenolics. In case of flavonoids, three isolates showed presence of rutin with S. rochei MSCA130 having the highest rutin content (0.95 µg g-1 fresh weight). The results of this study showed high genetic diversity and antioxidant potential among the Streptomyces isolates.

Role of metabolites in flower development and discovery of compounds controlling flowering time.

Flowering is one of the most important physiological processes of plants that ensures continuity of genetic flow from one generation to the next and also maintains food security. Therefore, impact of various climate-related abiotic stresses on flowering have been assessed to evaluate the long-term impact of global climate change. In contrast to the enormous volume of research that has been conducted at the genetic, transcriptional, post-transcriptional, and protein level, much less attention has been paid to understand the role of various metabolites in flower induction and floral organ development during normal growth or in stressed environmental condition. This review article aims at summarizing information on various primary (e.g., carbohydrates, lipids, fatty acid derivatives, protein and amino acids) and secondary metabolites (e.g., polyamines, phenolics, neuro-indoles, phenylpropanoid, flavonoids and terpenes) that have so far been identified either during flower induction or in individual floral organs implying their possible role in organ development. Specialized metabolites responsible for flower colour, scent and shape to support plant-pollinator interaction have been extensively reviewed by many research groups and hence are not considered in this article. Many of the metabolites discussed here may be used as metabolomarkers to identify tolerant crop genotypes. Several agrochemicals have been successfully used to release endodormancy in temperate trees. Along the same line, a strategy that combines metabolite profiling, screening of small-molecule libraries, and structural alteration of selected compounds has been proposed in order to identify novel lead compounds that can regulate flowering time when applied exogenously.

Effect of Pulse Electrodeposition Parameters on the Microstructure and Mechanical Properties of Ni-W/B Nanocomposite Coatings.

In this work, Ni−W/B nanocomposite coatings were successfully fabricated on low carbon steel by using pulse current (PC) electrodeposition. The effects of the frequency and duty cycle on the microstructure, wear resistance, and microhardness of the coatings were studied. The results obtained show that the distribution and content of boron particles (>4 wt.%) in the PC electrodeposition coatings are significantly better than those of direct current (DC) electrodeposition coatings (less than 4 wt.%). The hardness results reveal that the highest microhardness of 1122 HV can be obtained at a frequency of 100 Hz and duty cycle of 30%. Furthermore, the relationship between the microstructure and mechanical properties was discussed.

Static Permittivity and Electro-Optical Properties of Bi-Component Orthoconic Antiferroelectric Liquid Crystalline Mixtures Targeted for Polymer Stabilized Sensing Systems.

The behavior of two newly formulated bi-component orthoconic antiferroelectric liquid crystalline (OAFLC) systems, i.e., the Compound A + Compound B mixture system and Compound C + Compound B mixture system has been discussed in light of temperature and concentration dependencies of helical pitch length, spontaneous polarization, relaxation time, bulk viscosity, and the anchoring energy strength coefficient, together with static dielectric permittivity (ε) and dielectric anisotropy. Compound A + Compound B mixtures possess spontaneous polarization between 190-340 nC.cm-2 and fast relaxation times between 190-320 µs in the smectic antiferroelectric SmCA* phase at room temperature. Compound C + Compound B mixtures also have a spontaneous polarization in the range of 190-280 nC.cm-2 and relaxation times in the range of 190-230 µs at room temperature. Most of the mixtures have a helical pitch below one micrometer in the SmCA* phase. These advanced mixtures show a broad temperature range of the antiferroelectric SmCA* phase, fast switching of molecules under an applied electric field, negative dielectric anisotropy and a short helical pitch, confirming the advantage of designing new polymer-stabilized OAFLC that is targeted for novel application in sensing devices, utilizing the fast responsive electro-optical modulation elements.

Ramifications of Vorticity on Aggregation and Activation of Platelets in Bi-Leaflet Mechanical Heart Valve: Fluid-Structure-Interaction Study.

Bileaflet mechanical heart valves (BMHV) are widely implanted to replace diseased heart valves. Despite many improvements in design, these valves still suffer from various complications, such as valve dysfunction, tissue overgrowth, hemolysis, and thromboembolism. Thrombosis and thromboembolism are believed to be initiated by platelet activation due to contact with foreign surfaces and nonphysiological flow patterns. The implantation of the valve causes nonphysiological patterns of vortex shedding behind the leaflets. This study signifies the importance of vorticity in platelet activation and aggregation in BMHV implants. A two-phase model with the first Eulerian phase for blood and the second discrete phase for platelets is used here. The generalized cross model of viscosity has been used to simulate the non-Newtonian viscosity of blood. A fluid-structure-interaction model has been used to simulate the motion of leaflets. This study has also estimated the platelet activation state (PAS), which is the mathematical estimation of the degree of activation of platelets due to flow-induced shear stresses that cause thrombus formation. The regions in the fluid domain with a higher vorticity field have been found to contain platelets with relatively higher PAS than regions with relatively lower vorticity fields. Also, this study has quantitatively reported the effect of vorticity on platelet aggregation. Platelet densities in fluid areas with higher vorticity are higher than densities in fluid areas with lower vorticity, indicating that highly activated platelets aggregate in areas with stronger vorticity.

Studies on Reproductive Development and Breeding Habit of the Commercially Important Bamboo Bambusa tulda Roxb.

Compared to other grasses, flowering in bamboo is quite divergent, yet complex with respect to time to flower, number of individual culms in a population that have been induced at a time (sporadic vs. gregarious), nature of monocarpy, morphology of inflorescences (solitary spikelet vs. pseudospikelet), biology of pollen and nature of genetic compatibility. Wide diversity exists even across species and genotypes. However, due to the rarity of flowering and inaccessibility, few studies have been done to systematically analyse diverse aspects of the reproductive behaviour of bamboo. In this study, four recurrently occurring, sporadic flowering populations of Bambusa tulda have been closely observed over the last seven years. Detailed inflorescence and floral morphology and development of reproductive organs have been studied. Pollen viability was assessed by staining and in vitro germination. Self and cross pollination experiments were performed in a plantation site to assess the genetic nature of pollen-pistil interaction. The study identifies interesting reproductive features, that are not common in other grasses. A few important observations include the early appearance of a solitary spikelet vs. late appearance of a pseudospikelet in the flowering cycle, low rate of pollen germination, protandry, self-incompatibility and higher rate of seed setting by the pseudospikelet as compared to the solitary spikelet. The findings will not only be useful to understand the reproductive behaviour of this non-woody timber plant, but will also be useful for forest management and sustainable use of bamboo bioresources.

Effect of foam insertion in aneurysm sac on flow structures in parent lumen: relating vortex structures with disturbed shear.

Numerous studies suggest that disturbed shear, causing endothelium dysfunction, can be related to neighboring vortex structures. With this motivation, this study presents a methodology to characterize the vortex structures. Precisely, we use mapping and characterization of vortex structures' changes to relate it with the hemodynamic indicators of disturbed shear. Topological features of vortex core lines (VCLs) are used to quantify the changes in vortex structures. We use the Sujudi-Haimes algorithm to extract the VCLs from the flow simulation results. The idea of relating vortex structures with disturbed shear is demonstrated for cerebral arteries with aneurysms virtually treated by inserting foam in the sac. To get physiologically realistic flow fields, we simulate blood flow in two patient-specific geometries before and after foam insertion, with realistic velocity waveform imposed at the inlet, using the Carreau-Yasuda model to mimic the shear-thinning behavior. With homogenous porous medium assumption, flow through the foam is modeled using the Forchheimer-Brinkman extended Darcy model. Results show that foam insertion increases the number of VCLs in the parent lumen. The average length of VCL increases by 168.9% and 55.6% in both geometries. For both geometries under consideration, results demonstrate that the region with increased disturbed shear lies in the same arterial segment exhibiting an increase in the number of oblique VCLs. Based on the findings, we conjecture that an increase in oblique VCLs is related to increased disturbed shear at the neighboring portion of the arterial wall.

Assessment and visualization of hemodynamic loading in aneurysm sac and neck: Effect of foam insertion.

Shape memory polymer (SMP) foam is often proposed as the future alternative of coils in aneurysm treatment devices. Present work numerically investigates the unsteady, three-dimensional simulation of blood flow in a cerebral aneurysm filled with SMP foam. Simulations are conducted on patient-specific geometries with realistic blood velocity waveform imposed at the inlet while SMP foam is treated as a porous medium. The present study introduces a "loading risk map" that helps to visualize the hemodynamic effect of foam insertion on the aneurysm sac and neck. The loading risk maps suggest that while the SMP foam subdues the flow and wall shear pulsations in the aneurysm sac, the pressure distribution is minimally affected. The maps suggest that while the downstream lip is the most risk-prone site for both geometries, downstream vascular anatomy significantly influences foam efficiency in reducing pressure and wall shear stress loading.

Identification and functional characterization of two bamboo FD gene homologs having contrasting effects on shoot growth and flowering.

Bamboos, member of the family Poaceae, represent many interesting features with respect to their fast and extended vegetative growth, unusual, yet divergent flowering time across species, and impact of sudden, large scale flowering on forest ecology. However, not many studies have been conducted at the molecular level to characterize important genes that regulate vegetative and flowering habit in bamboo. In this study, two bamboo FD genes, BtFD1 and BtFD2, which are members of the florigen activation complex (FAC) have been identified by sequence and phylogenetic analyses. Sequence comparisons identified one important amino acid, which was located in the DNA-binding basic region and was altered between BtFD1 and BtFD2 (Ala146 of BtFD1 vs. Leu100 of BtFD2). Electrophoretic mobility shift assay revealed that this alteration had resulted into ten times higher binding efficiency of BtFD1 than BtFD2 to its target ACGT motif present at the promoter of the APETALA1 gene. Expression analyses in different tissues and seasons indicated the involvement of BtFD1 in flower and vegetative development, while BtFD2 was very lowly expressed throughout all the tissues and conditions studied. Finally, a tenfold increase of the AtAP1 transcript level by p35S::BtFD1 Arabidopsis plants compared to wild type confirms a positively regulatory role of BtFD1 towards flowering. However, constitutive expression of BtFD1 had led to dwarfisms and apparent reduction in the length of flowering stalk and numbers of flowers/plant, whereas no visible phenotype was observed for BtFD2 overexpression. This signifies that timely expression of BtFD1 may be critical to perform its programmed developmental role in planta.

Gene duplication and stress genomics in Brassicas: Current understanding and future prospects.

Polyploidy or whole genome duplication (WGD) is an evolutionary phenomenon that happened in all angiosperms multiple times over millions of years. Extensive studies on the model plant Arabidopsis thaliana genome have revealed that it has undergone five rounds of WGDs followed, in the Brassicaceae tribe, by a characteristic whole genome triplication (WGT). In addition, small-scale events such as tandem or segmental duplications and retrotransposition also enable plants to reshape their genomes. Over the decades, extensive research efforts have been undertaken to understand the evolutionary significance of polyploidy. On the other hand, much less attention has been paid to understanding the impact of gene duplication on the diversification of important stress response genes. The main objective of this review is to discuss key aspects of gene and genome duplications with a focus on genes primarily regulated by osmotic stresses. The focal family is the Brassicaceae, since it (i) underwent multiple rounds of WGDs plus WGTs, (ii) hosts many economically important crops and wild relatives that are tolerant to a range of stresses, and (iii) comprises many species that have already been sequenced. Diverse molecular mechanisms that lead to structural and regulatory alterations of duplicated genes are discussed. Examples are drawn from recent literature to elucidate expanded, stress responsive gene families identified from different Brassica crops. A combined bioinformatic and transcriptomic method has been proposed and tested on a known stress-responsive gene pair to prove that stress-responsive duplicated allelic variants can be identified by this method. Finally, future prospects for engineering these genes into crops to enhance stress tolerance are discussed, and important resources for Brassica genome research are provided.

Nose to brain delivery of antiretroviral drugs in the treatment of neuroAIDS.

NeuroAIDS (Neuro Acquired Immunodeficiency Syndrome) or HIV (Human Immunodeficiency Virus) associated neuronal abnormality is continuing to be a significant health issue among AIDS patients even under the treatment of combined antiretroviral therapy (cART). Injury and damage to neurons of the brain are the prime causes of neuroAIDS, which happens due to the ingress of HIV by direct permeation across the blood-brain barrier (BBB) or else via peripherally infected macrophage into the central nervous system (CNS). The BBB performs as a stringent barricade for the delivery of therapeutics drugs. The intranasal route of drug administration exhibits as a non-invasive technique to bypass the BBB for the delivery of antiretroviral drugs and other active pharmaceutical ingredients inside the brain and CNS. This method is fruitful for the drugs that are unable to invade the BBB to show its action in the CNS and thus erase the demand of systemic delivery and thereby shrink systemic side effects. Drug delivery from the nose to the brain/CNS takes very less time through both olfactory and trigeminal nerves. Intranasal delivery does not require the involvement of any receptor as it occurs by an extracellular route. Nose to brain delivery also involves nasal associated lymphatic tissues (NALT) and deep cervical lymph nodes. However, very little research has been done to explore the utility of nose to brain delivery of antiretroviral drugs in the treatment of neuroAIDS. This review focuses on the potential of nasal route for the effective delivery of antiretroviral nanoformulations directly from nose to the brain.

Measurement of visco-elastic properties in a binary system of hockey stick-shaped and calamitic mesogens.

Temperature variation of the splay elastic modulus (K11) and rotational viscosity ([Formula: see text]) have been measured throughout the entire nematic (N phase of a binary liquid crystal system comprising of host calamitic compound, 4'-octyloxy-4-cyanobiphenyl (8OCB) and small amount of a hockey stick-shaped mesogen, 4-(3-decyloxyphenyliminomethyl) phenyl 4-decyloxycinnamate (SF7). Two different structural conformations play a significant role in the phase behavior leading to a noticeable shrinkage in the nematic width. During cooling in the nematic phase, both K11 and [Formula: see text] enhance monotonically and divulge an evidence of pretransitional fluctuation near the Smectic-A (Sm-A) transition. With increase in the dopant concentration, the slope of the temperature-dependent K11 and [Formula: see text] becomes uniformly steeper. The observed variations are explained in accordance with the formation of smectic-like clusters in the nematic phase. A representative model of the smectic-like clusters in the nematic phase is presented. However, the obtained values of [Formula: see text] have found to be between that of conventional calamitics and typical bent-core mesogens. Measurement of the temperature-dependent orientational order parameter (〈P2〉 ) and activation energy (Ea) has also been carried out for all the studied mixtures, exhibiting a small augmentation due to the addition of a hockey stick-shaped compound. This indicates an enhancement in intermolecular packing within the mixtures which further influences the molecular motions.

Influence of Co2+ Ions on the Microstructure and Mechanical Properties of Ni-W/Diamond Nano-Composite Coatings.

The Co were incorporated into the Ni-W/diamond nano-composite coatings by introducing CoSO4 in the aforesaid plating bath. The effects of the Co content in the electrodeposit on microstructure and mechanical properties were analyzed. The morphology and the composition of the deposits were investigated by means of SEM and EDS, respectively. The Co content in the coatings increases progressively upon increasing the amount of CoSO4 in the plating bath. The addition of small amount of CoSO4 in the plating bath tends to enhance the hardness and wear performance of the Ni-W/diamond nano-composite coatings. While the amount of CoSO4 beyond 0.2 g/L in the plating bath, the hardness and the wear resistance of the coatings decrease sharply.

Multidrug-resistant Staphylococcus pettenkoferi isolated from cat in India.

BACKGROUND AND AIM: Coagulase-negative staphylococci (CoNS) are considered to be one of the emerging pathogens in human and animals in recent times. Staphylococcus pettenkoferi, a novel pathogen under CoNS, is discovered in 2002 in humans with multiple clinical manifestations in various patients. To date, the pathogens have not yet been reported from any animals. The present study reported the first ever isolation, identification, and characterization of multidrug-resistant S. pettenkoferi from a cat with peritonitis in India. MATERIALS AND METHODS: Peritoneal fluid was collected aseptically from 3 years old cat processed for bacteriological culture by standard techniques. Isolates were confirmed by BD Phoenix™ automated bacterial identification system and were subjected to plate and tube coagulase tests. All the isolates were tested for antimicrobial sensitivity profile by disc diffusion assay, extended-spectrum ß-lactamase production by double disc diffusion assay, in vitro biofilm production ability by microtiter plate assay, and detection of virulence genes and mecA gene by polymerase chain reaction assay. RESULTS: A total of five clonally expanded isolates of S. pettenkoferi were isolated from peritoneal fluid of the affected cat. All the isolates were resistant against 36 antimicrobial agents and were also methicillin-resistant staphylococci. Phenotypically, all the isolates were negative for biofilm production but were carrying multiple biofilm-producing genes (icaA, IS257, nuc, and mecA). CONCLUSION: Although S. pettenkoferi was previously reported once from animal (cat) environment, this is probably the first ever report of isolation of the organism directly from any animals. This is also probably the first report from any species in India.

Stereoselective Synthesis of Pyrroloisoindolone and Pyridoisoindolone via aza-Prins Cyclization of Endocyclic N-Acyliminium Ions.

A simple methodology has been developed for the synthesis of substituted pyrroloisoindolone and pyridoisoindolone via aza-Prins cyclization of endocyclic N-acyliminium ions, which are derived from the triflic acid treatment of regioselectively reduced N-homopropargyl imides in excellent yields. The reaction is highly diastereoselective, and only one diastereoisomer is formed during the reaction. The methodology can be utilized for the synthesis of pyrimidoisoindole.

Identification, characterization and gene expression analyses of important flowering genes related to photoperiodic pathway in bamboo.

BACKGROUND: Bamboo is an important member of the family Poaceae and has many inflorescence and flowering features rarely observed in other plant groups. It retains an unusual form of perennialism by having a long vegetative phase that can extend up to 120 years, followed by flowering and death of the plants. In contrast to a large number of studies conducted on the annual, reference plants Arabidopsis thaliana and rice, molecular studies to characterize flowering pathways in perennial bamboo are lacking. Since photoperiod plays a crucial role in flower induction in most plants, important genes involved in this pathway have been studied in the field grown Bambusa tulda, which flowers after 40-50 years. RESULTS: We identified several genes from B. tulda, including four related to the circadian clock [LATE ELONGATED HYPOCOTYL (LHY), TIMING OF CAB EXPRESSION1 (TOC1), ZEITLUPE (ZTL) and GIGANTEA (GI)], two circadian clock response integrators [CONSTANS A (COA), CONSTANS B (COB)] and four floral pathway integrators [FLOWERING LOCUS T1, 2, 3, 4 (FT1, 2, 3, 4)]. These genes were amplified from either gDNA and/or cDNA using degenerate as well as gene specific primers based on homologous sequences obtained from related monocot species. The sequence identity and phylogenetic comparisons revealed their close relationships to homologs identified in the temperate bamboo Phyllostachys edulis. While the four BtFT homologs were highly similar to each other, BtCOA possessed a full-length B-box domain that was truncated in BtCOB. Analysis of the spatial expression of these genes in selected flowering and non-flowering tissue stages indicated their possible involvement in flowering. The diurnal expression patterns of the clock genes were comparable to their homologs in rice, except for BtZTL. Among multiple BtCO and BtFT homologs, the diurnal pattern of only BtCOA and BtFT3, 4 were synchronized in the flower inductive tissue, but not in the non-flowering tissues. CONCLUSION: This study elucidates the photoperiodic regulation of bamboo homologs of important flowering genes. The finding also identifies copy number expansion and gene expression divergence of CO and FT in bamboo. Further studies are required to understand their functional role in bamboo flowering.

Lipid-based nanocarrier efficiently delivers highly water soluble drug across the blood-brain barrier into brain.

Delivering highly water soluble drugs across blood-brain barrier (BBB) is a crucial challenge for the formulation scientists. A successful therapeutic intervention by developing a suitable drug delivery system may revolutionize treatment across BBB. Efforts were given here to unravel the capability of a newly developed fatty acid combination (stearic acid:oleic acid:palmitic acid = 8.08:4.13:1) (ML) as fundamental component of nanocarrier to deliver highly water soluble zidovudine (AZT) as a model drug into brain across BBB. A comparison was made with an experimentally developed standard phospholipid-based nanocarrier containing AZT. Both the formulations had nanosize spherical unilamellar vesicular structure with highly negative zeta potential along with sustained drug release profiles. Gamma scintigraphic images showed both the radiolabeled formulations successfully crossed BBB, but longer retention in brain was observed for ML-based formulation (MGF) as compared to soya lecithin (SL)-based drug carrier (SYF). Plasma and brain pharmacokinetic data showed less clearance, prolonged residence time, more bioavailability and sustained release of AZT from MGF in rats compared to those data of the rats treated with SYF/AZT suspension. Thus, ML may be utilized to successfully develop drug nanocarrier to deliver drug into brain across BBB, in a sustained manner for a prolong period of time and may provide an effective therapeutic strategy for many diseases of brain. Further, many anti-HIV drugs cannot cross BBB sufficiently. Hence, the developed formulation may be a suitable option to carry those drugs into brain for better therapeutic management of HIV.

Surface modified kokum butter lipid nanoparticles for the brain targeted delivery of nevirapine.

AIM: The present work investigates the efficacy of Polysorbate 80(P80) coated Kokum butter (KB) solid lipid nanoparticles (P80NvKLNs) for the brain targeted delivery of Nevirapine (Nv). METHODS: Solid lipid nanoparticles (SLNs) were prepared by nanoprecipitation technique and evaluated for drug excipient compatibility studies, z- average particle size (nm), zeta potential (mv), percentage drug entrapment efficiency (%EE), surface morphology and in-vitro drug release properties. The in-vivo biodistribution and brain targeting efficiency of nanoparticles were studied in healthy male Wistar rat (150-200 g). RESULTS: P80NvKLNs were found to be smooth surfaced, spherical shaped having average particle size of 177.80 ± 0.82 nm, zeta potential of -8.91 ± 4.36 mv and %EE of 31.32 ± 0.42%. P80NvKLNs remained in blood circulation for 48 h maintaining a sustained release in brain for 24 h (p < 0.05). CONCLUSION: The study proves the efficacy of Polysorbate 80 coated Kokum butter nanoparticles for brain-targeted delivery of drugs providing ample opportunities for further study.