Square Lattice Formation in a Monodisperse Complex Plasma.

We present the first observations of a square lattice formation in a monodisperse complex plasma system, a configurational transition phenomenon that has long been an experimental challenge in the field. The experiments are conducted in a tabletop L-shaped dusty plasma experimental device in a dc glow discharge Argon plasma environment. By a careful control of the vertical potential confining the charged particles as well as the strength of the ion wake charge interactions with the dust particles, we are able to steer the system toward a crystalline phase that exhibits a square lattice configuration. The transition occurs when the vertical confinement strength is slightly reduced below a critical value leading to a buckling of the monodisperse hexagonal 2D dust crystal to form a narrowly separated bilayer state (a quasi-2D state). Some theoretical insights into the transition process are provided through molecular dynamics simulations carried out for the parameters relevant to our experiment.

In vivo and in vitro antimicrobial activity of phytol, a diterpene molecule, isolated and characterized from Adhatoda vasica Nees. (Acanthaceae), to control severe bacterial disease of ornamental fish, Carassius auratus, caused by Bacillus licheniformis PKBMS16.

Bacillus licheniformis, a pathogenic new strain of bacteria is considered as the main cause of high mortalities and economic losses among the ornamental fish farms of India. The present study aimed to investigate the anti-bacterial and Immunostimulant activity of three selected Indian medicinal plants, Allium sativum, Adhatoda vasica and Centella asiatica for treating Bacillus licheniformis PKBMS16 by subsequent experimental and clinical trials using different organic polar and non-polar solvents. The antimicrobial and Immunostimulant activity of methanolic crude extracts of Adhatoda vasica was fractions and active constituents was further characterized by chromatography and mass spectroscopy studies using FTIR, 1HNMR and 13c NMR to identify as well as to determine the nature of the pure compound which is phytol (C20H40O), a diterpene alcohol with a molecular weight of m/z 297. In order to study the in vivo anti-pathogenic influence of the biologically active compounds, phytol were incorporated to the artificial diets at the concentration of 2, 5 and 8 mg/kg and fed to the1.0 × 105 CFU/ml of Bacillus licheniformis PKBMS16 injected experimentally challenged ornamental goldfish Carassius auratus for twenty days. Phytol treated group significantly (P < 0.01 and P < 0.05) reduced the rate of fish mortality. After the termination of survivability assay the estimation of hemato-biochemical parameters have been performed and revealed the significant recovery of health condition on 20th days post treatment. Therefore, the present study concluded that the low toxicity along with high bioactivity and tolerance by lower vertebrate supports the potential of phytol as a new compound for inducing fish immunity.

Molecular characterization of newly identified Klebsiella PKBSG14 and analysis of its effect on immune response and cell cycle progression using common catfish (Channa punctatus) as a model.

Microbial studies on Catfish revealed that Klebsiella is the most common pathogen causing prevalence of ulcers, fin erosion, and other lesions. During this study, a new strain of bacteria was isolated from Channa punctatus, and molecular identification by 16srRNA revealed the strain was Klebsiella PKBSG14 (Accession no KJ162158). The strain was also PCR positive for two virulent gene wcaG (Accession no LN606595) and rmpA (Accession no LN606594) responsible for inflammatory reactions and induction of innate immune response in the host cell. To study innate immune response induced by pathogenic infection the phagocytic interactive process between the spleen macrophages and KlebsiellaPKBSG14 was investigated using optical microscopy. FACS of splenic macrophages revealed that the phagocytic interaction leads to the process of macrophage cell cycle progression. A detailed study on the macrophage DNA content by performing DNA fragmentation and comet allowed us to study simultaneously host cell division as a function of phagocytosis and the findings unveiled the fact that Phagocytosis of KlebsiellaPKBSG14 aided in macrophage cell cycle progression but was less likely to complete mitosis. Here we also report the cytotoxic effect linked to the infection with KlebsiellaPKBSG14 by performing Cell viability assay, intracellular production of ROS, and mitochondrial transmembrane potential where it manifested itself in impaired cellular function. So, in summary, we simultaneously discovered a new strain of bacteria ie. Klebsiella PKBSG14 as well as deliberately attempted to study the immunomodulatory effect of isolated new stain on Channa punctatus by performing host-pathogen phagocytic interactive experiments, the cell cycle state of the host cell and pathogen-mediated cytotoxicity along with genotoxicity, and our results evidence a new immunomodulatory effect of KlebsiellaPKBSG14 infection on fish splenic macrophages.

Studies on histopathological alteration of three major organs of the goldfish, Carassius auratus L., of India due to myxozoan infection with special reference to scanning electron microscopic observation.

Severe infections by the protozoan parasite belonging to the genera Myxozoa are causing serious problems in ornamental fish reared in breeding farms. Histopathological study is being used for diagnosis of the severity of diseases. Myxozoan infections result in large scale histopathological damages in different fish tissues. No information is available regarding the histopathological changes of goldfish due to infection with myxozoans. The present study deals with the histopathological changes of the gill, fin, and skin of goldfish, infected with myxozoan parasites along with an ultrastructural study using scanning electron microscope. Several histological alterations have been observed in goldfish, like tissue damage, epithelial hyperplasia, necrosis, anoxia, localized lymphocytic infiltration, excess mucus, cellular necrosis, and epithelial proliferation. The present study revealed the invasion intensified by the occurrence of morphological lesions in the gill, skin, and fin exposed to Myxosporidia, which may lead to respiratory insufficiency in fish and even cause mass mortality.

Kelvin-Helmholtz instability in a compressible dust fluid flow.

We report the first experimental observations of a single-mode Kelvin-Helmholtz instability in a flowing dusty plasma in which the flow is compressible in nature. The experiments are performed in an inverted [Formula: see text]-shaped dusty plasma experimental device in a DC glow discharge Argon plasma environment. A gas pulse valve is installed in the experimental chamber to initiate directional motion to a particular dust layer. The shear generated at the interface of the moving and stationary layers leads to the excitation of the Kelvin-Helmholtz instability giving rise to a vortex structure at the interface. The growth rate of the instability is seen to decrease with an increase in the gas flow velocity in the valve and the concomitant increase in the compressibility of the dust flow. The shear velocity is further increased by making the stationary layer to flow in an opposite direction. The magnitude of the vorticity is seen to become stronger while the vortex becomes smaller with such an increase of the shear velocity. A molecular dynamics simulation provides good theoretical support to the experimental findings.

Cytoprotective role of the aqueous extract of Terminalia chebula on renal epithelial cells.

PURPOSE: Kidney stone is one of the most prevalent diseases worldwide. Calcium oxalate (CaOx) has been shown to be the main component of the majority of stones formed in the urinary system of the patients with urolithiasis. The present study evaluates the antilithiatic properties of Terminalia chebula commonly called as ″harad ″ which is often used in ayurveda to treat various urinary diseases including kidney stones. MATERIALS AND METHODS: The antilithiatic activity of Terminalia chebula was investigated on nucleation and growth of the calcium oxalate crystals. The protective potency of the plant extract was also tested on oxalate induced cell injury of both NRK-52E and MDCK renal epithelial cells. RESULTS: The percentage inhibition of CaOx nucleation was found 95.84 % at 25µg/mL of Terminalia chebula aqueous extract which remained almost constant with the increasing concentration of the plant extract; however, plant extract inhibited CaOx crystal growth in a dose dependent pattern. When MDCK and NRK-52E cells were injured by exposure to oxalate for 48 hours, the aqueous extract prevented the injury in a dose-dependent manner. On treatment with the different concentrations of the plant extract, the cell viability increased and lactate dehydrogenase release decreased in a concentration dependent manner. CONCLUSION: Our study indicates that Terminalia chebula is a potential candidate for phytotherapy against urolithiasis as it not only has a potential to inhibit nucleation and the growth of the CaOx crystals but also has a cytoprotective role.

Auto-correlations of microscopic density fluctuations for Yukawa fluids in the generalized hydrodynamics framework with viscoelastic effects.

The present work develops a theoretical procedure for obtaining transport coefficients of Yukawa systems from density fluctuations. The dynamics of Yukawa systems are described in the framework of the generalized hydrodynamic (GH) model that incorporates strong coupling and visco-elastic memory effects by using an exponentially decaying memory function in time. A hydrodynamic matrix for such a system is exactly derived and then used to obtain an analytic expression for the density autocorrelation function (DAF)-a marker of the time dynamics of density fluctuations. The present approach is validated against a DAF obtained from numerical data of Molecular Dynamics (MD) simulations of a dusty plasma system that is a practical example of a Yukawa system. The MD results and analytic expressions derived from the model equations are then used to obtain various transport coefficients and the latter are compared with values available in the literature from other models. The influence of strong coupling and visco-elastic effects on the transport parameters are discussed. Finally, the utility of our calculations for obtaining reliable estimates of transport coefficients from experimentally determined DAF is pointed out.

Self-sustained non-equilibrium co-existence of fluid and solid states in a strongly coupled complex plasma system.

A complex (dusty) plasma system is well known as a paradigmatic model for studying the kinetics of solid-liquid phase transitions in inactive condensed matter. At the same time, under certain conditions a complex plasma system can also display characteristics of an active medium with the micron-sized particles converting energy of the ambient environment into motility and thereby becoming active. We present a detailed analysis of the experimental complex plasmas system that shows evidence of a non-equilibrium stationary coexistence between a cold crystalline and a hot fluid state in the structure due to the conversion of plasma energy into the motion energy of microparticles in the central region of the system. The plasma mediated non-reciprocal interaction between the dust particles is the underlying mechanism for the enormous heating of the central subsystem, and it acts as a micro-scale energy source that keeps the central subsystem in the molten state. Accurate multiscale simulations of the system based on combined molecular dynamics and particle-in-cell approaches show that strong structural nonuniformity of the system under the action of electostatic trap makes development of instabilities a local process. We present both experimental tests conducted with a complex plasmas system in a DC glow discharge plasma and a detailed theoretical analysis.

Pattern formation in a complex plasma in high magnetic fields.

Low-pressure room-temperature neon, argon, krypton, and air plasmas were studied in magnetic fields up to flux densities of 2.3 T. Filaments appeared parallel to the magnetic field lines, and patterns such as spirals and concentric circles formed in the perpendicular direction. We link these effects to the magnetization of the ions. We also used a layer of embedded microparticles as probes in the plasma. Their motion changed dramatically from a collective rotation of the whole ensemble in moderate magnetic fields to a rotation in several small vortices centered at the filaments.

In vivo site-directed mutagenesis of the factor IX gene by chimeric RNA/DNA oligonucleotides.

A chimeric RNA/DNA oligonucleotide was constructed to induce a sequence mutation in the rat factor IX gene, resulting in prolonged coagulation. Oligonucleotides were targeted to hepatocytes in cell culture or in vivo by intravenous injection. Nucleotide conversion was both site-specific and dose-dependent. The mutated gene was associated in vivo with significantly reduced factor IX coagulant activity and a marked prolongation of the activated partial thromboplastin time. The results demonstrate that single base-pair alterations can be introduced in hepatocytes in situ by RNA/DNA oligonucleotides, suggesting a potentially powerful strategy for hepatic gene repair without the use of viral vectors.

Experimental observation of pinned solitons in a flowing dusty plasma.

Pinned solitons are a special class of nonlinear solutions created by a supersonically moving object in a fluid. They move with the same velocity as the moving object and thereby remain pinned to the object. A well-known hydrodynamical phenomenon, they have been shown to exist in numerical simulation studies but to date have not been observed experimentally in a plasma. In this paper we report the first experimental excitation of pinned solitons in a dusty (complex) plasma flowing over a charged obstacle. The experiments are performed in a Π shaped dusty plasma experimental (DPEx) device in which a dusty plasma is created in the background of a DC glow discharge Ar plasma using micron sized kaolin dust particles. A biased copper wire creates a potential structure that acts as a stationary charged object over which the dust fluid is made to flow at a highly supersonic speed. Under appropriate conditions nonlinear stationary structures are observed in the laboratory frame that correspond to pinned structures moving with the speed of the obstacle in the frame of the moving fluid. A systematic study is made of the propagation characteristics of these solitons by carefully tuning the flow velocity of the dust fluid by changing the height of the potential structure. It is found that the nature of the pinned solitons changes from a single-humped one to a multihumped one and their amplitudes increase with an increase of the flow velocity of the dust fluid. The experimental findings are then qualitatively compared with the numerical solutions of a model forced Korteweg de Vries (fKdV) equation.

Evidence of the American Myxobolus dechtiari was introduced along with its host Lepomis gibbosus in Europe: Molecular and histological data.

The American pumpkinseed Lepomis gibbosus, was introduced to Europe more than one hundred years ago. Currently it is a common fish in European freshwaters but relatively few specific parasites infect this fish in this new habitat. In Europe only a single species, Myxobolus dechtiari seems to represent the American myxosporean fauna of centrarchid fishes. M. dechtiari was found in both Portugal and Hungary. This species forms plasmodia with elongated shape inside the cartilaginous rays of gill filaments. In the advanced stage of infection, after disruption of plasmodia, small groups of myxospores remain enclosed in the cartilaginous gill rays causing distortions in the filaments. Myxospores were ellipsoidal in frontal view and lemon-shape in sutural, length 12.5 ± 0.46 (12-13.4) µm, width 10 ± 0.37 (9.6-10.4) µm, and thickness 7.4 ± 0.37 (7-8) µm; the polar capsules were pyriform, equal in size, length 5.6 ± 0.21 (5.3-6) µm, width 3.2 ± 0.16 (3-3.6) µm; Seven to eight polar tube coils were arranged perpendicularly to the capsule length. There was a small, round, 0.4 ± 0.1 (0.3-05) (N = 50) intercapsular appendix in the spores. The small subunit ribosomal DNA (ssrDNA) of M. dechtiari differed from other myxozoans sequenced to date. Phylogenetic analysis of the ssrDNA gene sequence placed this species in a clade including actinospores and Myxobolus species: Raabeia type1, Triactinomyxon sp., and Myxobolus osburni infecting the same host fish. The focus of our study was to prove that the pumpkinseed, a fish originated from North-America introduced one of its myxosporean parasite to Europe. Emphasis was put on to demonstrate the unique feature of this parasite causing infection in the cartilaginous gill rays.

Experimental observation of a first-order phase transition in a complex plasma monolayer crystal.

The formation and melting of a monolayered charged dust particle crystal in a DC glow discharge argon plasma is studied. The nature of the melting or formation process is established as a first-order phase transition from the variations in the Coulomb coupling parameter, the dust temperature, the structural order parameter, and from the existence of a hysteresis behavior. Our experimental results are distinctly different from existing theoretical predictions for two dimensional crystals based on the Kosterlitz-Thouless-Halperin-Nelson-Young mechanism or the grain boundary induced melting and indicate a mechanism that is akin to a fluctuation induced first-order phase transition in complex plasmas.

Morphological and ssrDNA sequence based molecular characterization of a novel Thelohanellus species (Myxosporea: Myxobolidae) infecting the fins of Goldfish, Carassius auratus L. with special reference to its histopathological alteration.

A new species of myxozoan, Thelohanellus goldi n. sp. is described using morphological and molecular data, parasitizing the fin filaments from 18 of 25 host specimens (72.5%) of Carassius auratus collected from different ornamental fish farms of India. Mature spore of the new species were oval to spherical in frontal view having rounded posterior ends and tapering anterior end measures 8.7-10.26 (9.50) × 4.10-7.89 (5.84) µm. The single large polar capsule, round to oval in shape but slightly pointed at the anterior end measuring 4.91-7.63 (5.60) × 2.3-3.1 (2.96) µm and located just below the anterior end of the spore. Polar filament only at distal end with 5-6 loose coils. The most differentiating feature from closely related species was carried out by morpho-taxonomic affinities with previously described species which are tremendously supported by molecular taxonomy by partial sequencing of the 18S rDNA gene resulted in a total of 2124 bp fragment of newly obtained small subunit ribosomal RNA gene sequence of the new species which Exhibit 93-95% homogeneity with other closely related species available in GenBank. The BLAST search and high genetic diversity of distance matrix of Myxobolus sp. did not properly match with any available sequences in GenBank and make sister clade with Thelohanellus caudatus and Thelohanellus habibpuri in the Thelohanellus clade including most of Thelohanellus spp. The study of evolutionary history enables us to understand the evolution of modern species and supports some uncertain topologies which are being presented regarding the morphometric analysis. The severity of myxozoan infection has been assessed in this article by observing the histopathological changes of fins of the C. auratus along with the diversity, distribution and taxonomic description of the new Thelohanellus species with their new host and locality records.

Expression from an internal AUG codon of herpes simplex thymidine kinase gene inserted in a retrovirus vector.

We identified structural features that affect the expression of an exogenous gene inserted into a retrovirus vector constructed by using spleen necrosis virus, an avian retrovirus. The thymidine kinase gene from herpes simplex virus type 1 containing deletions in the promoter and terminal sequences of the mRNA was inserted into spleen necrosis virus. We found that synthesis of thymidine kinase by the recovered virus was apparently initiated from internal AUG residues. At least in some cases, however, the level of expression depended on the number of AUGs and the nucleotide sequence around the AUGs that preceded the initiator codon of the thymidine kinase gene.

Expression of complete chicken thymidine kinase gene inserted in a retrovirus vector.

The chicken thymidine kinase (tk) gene was inserted into spleen necrosis virus. Thymidine kinase activity was expressed even when the promoter and terminator sequences for tk RNA synthesis were retained. When the promoter was present in the same orientation as the promoter in the long terminal repeat of the virus, deletions occurred both in the virus and in the tk gene, and the thymidine kinase-transforming activity of the recovered virus was low. Splicing of apparent intervening sequences in the tk gene was also observed. When the orientation of the tk promoter was opposite to the promoter in the long terminal repeat, virus synthesis was diminished, whereas thymidine kinase activity was expressed at an elevated level compared with virus in which the promoter was in the same orientation. However, when the apparent tk promoter was deleted from virus with the tk gene in the opposite orientation, a high level of virus synthesis was observed, probably as a result of absence of interference of RNA synthesis from converging promoters. The intervening sequences in the virus in which the promoters were in opposite orientation were not spliced.

Seasonal incidence of protozoan parasitic infestation in ornamental fishes of West Bengal, India.

The communication, dealing with the prevalence of protozoan parasites of the ornamental fish of West Bengal. During the study more than five hundred fish have been examined from five districts namely, Nadia, Hooghly, Howrah, North 24-pargana and South 24-pargana of West Bengal during pre-monsoon, monsoon and post-monsoon season. The study reveals that the intensity of infection is more in case of ciliate parasites. The highest ectoparasitic infection has been recorded during post-monsoon season, i.e. from November to February, followed by the pre-monsoon period while the lowest infection was recorded during monsoon i.e. from July to October which may lead to the conclusion that environmental factors are responsible for spreading infection.

Occurrence of two new species of the genus Dipartiella (Raabe, 1959) Stein 1961 (Ciliophora: Trichodinidae) isolated for the first time from ornamental fish.

During the parasitological survey of ornamental fish in India the authors identified two trichodinid ciliophorans for the first time in India, during the year 2014-16 and also revealed that goldfish, Carassius auratus, was the most susceptible species for trichodinid infection. Two ciliophorans have been isolated and identified on the basis of wet silver nitrate impregnation technique followed by taxonomic description, morphometric variability and comparative data with its closely related species. Considering all the important features including diameter, structure of denticles, rays and ciliatures the authors are of the opinion that the identified species are new to science. Hence, the name Dipartiella indiana n. sp. and Dipartiella carassii n. sp. are being proposed here. Till date, only two species of the genus have been described from the edible fish, but no attention has been paid to ornamental fish. Moreover, The present study confirms the first report of this genus from ornamental fish species and added two more species under the genus Dipartiella (Raabe, 1959) Stein 1961 along with new host, locality and prevalence rates.

Morphotaxonomical description of three new species of Myxobolus Bütschli, 1882 (Myxozoa: Myxosporea: Bivalvulida) from edible freshwater fishes of West Bengal, India.

Three new species of Myxobolus are described from the mucous membrane around gill lamellae of carps of West Bengal. The new species have been named as M. muralidharani sp. n., M. nilimae sp. n. from Labeo rohita, and M. harpreetae sp. n. from Labeo bata respectively. Spores of M. muralidharani sp. n. measured 13.84 ± 0.049 (13-14) × 4.95-6 (5.35) µm, with two elongated equal sized polar capsules. Spores of M. nilimae sp. n. measured 15.9-17.1 (16.65) µm × 6.2-7.5 (6.9) µm, with two equal petal shaped polar capsules, 9.0-11 (10.4) µm × 3-3.5 (3.16) µm. In contrast to aforementioned two new species, M. harpreetae sp. n. had two unequal polar capsules, 8.7-9.2 (9.149) µm × 2.9-4.0 (3.45) µm and 7.6-8.3 (7.94) µm × 2.8-3.3 (2.9) µm in each spore, 11.4-13.8 (13.2) µm × 4.9-7.8 (6.51) µm.

Monocystis julkae sp.nov., (Protista: Apicomplexa: Monocystidae) a new aseptate gregarine species of the genus Monocystis Stein, 1848 obtain from an Indian Earthworm, Eutyphoeus kherai, Julka, 1978.

During the course of a biodiversity survey of the endoparasitic aseptate gregarines in the Malda district of West Bengal, India, seminal vesicles of the earthworm, Eutyphoeus kherai, Julka 1978 were found to be infested with a new species, Monocystis julkae sp.nov., of the genus, Monocystis Stein (Arch Anat Phys Med 181-223, 1848). The trophozoite is elongated but slightly constricted posteriorly. A tail like protrusion appears in the posterior end. Anterior end is rather wider than the posterior one. The whole body size of the trophozoite measures 102.2-184.0 (126.7 ± 19.9) µm × 40.9-81.8 (58.2 ± 10.0) µm. Size of the nucleus ranges from 10.2 to 16.3 (11.9 ± 1.9) µm × 8.1-12.2 (8.8 ± 1.2) µm. The gametocysts are ovoidal containing two unequal gametocytes. Diameter of it measures 61.3-98.1 (75.8 ± 8.6) µm. Oocysts are navicular and measures 6.9-10.0 (8.7 ± 0.9) µm × 3.0-4.6 (4.3 ± 0.4) µm.