Spatially selective narrow band and broadband absorption in Ag/SiO2/Ag based trilayer thin films by oblique angle deposition of SiO2layer

We have experimentally demonstrated spatially selective absorption in Ag-SiO2-Ag based trilayer thin films by tuning the deposition angle of SiO2layer. These structures generate cavity resonance which can be tuned across the substrate locations due to spatially selective thickness and refractive index of silicon oxide (SiO2) film sandwiched between metallic silver (Ag) mirrors. Spatially selective property of SiO2film is obtained by oblique angle deposition technique using an electron beam evaporation system. The resonance wavelength of absorption in this trilayer structure shifts across the substrate locations along the direction of oblique deposition. The extent of shift in resonance increases with increase in angle of deposition of SiO2layer. 4.14 nm mm-1average shift of resonance wavelength is observed when SiO2is deposited at 40° whereas 4.76 nm mm-1average shift is observed when SiO2is deposited at 60°. We observed that the width of resonance increases with angle of deposition of the cavity layer and ultimately the resonant absorption disappears and becomes broadband when SiO2is deposited at glancing angle deposition (GLAD) configuration. Our study reveals that there is a suitable range of oblique angle of deposition from 40° to 60° for higher spatial tunability and resonant absorption whereas the absorption becomes broadband for glancing angle deposition.

Dynamic effects of ventral hippocampal NRG3/ERBB4 signaling on nicotine withdrawal-induced responses

Tobacco smoking remains a leading cause of preventable death in the United States, with approximately a 5% success rate for smokers attempting to quit. High relapse rates have been linked to several genetic factors, indicating that the mechanistic relationship between genes and drugs of abuse is a valuable avenue for the development of novel smoking cessation therapies. For example, various single nucleotide polymorphisms (SNPs) in the gene for neuregulin 3 (NRG3) and its cognate receptor, the receptor tyrosine-protein kinase erbB-4 (ERBB4), have been linked to nicotine addiction. Our lab has previously shown that ERBB4 plays a role in anxiety-like behavior during nicotine withdrawal (WD); however, the neuronal mechanisms and circuit-specific effects of NRG3-ERBB4 signaling during nicotine and WD are unknown. The present study utilizes genetic, biochemical, and functional approaches to examine the anxiety-related behavioral and functional role of NRG3-ERBB4 signaling, specifically in the ventral hippocampus (VH) of male and female mice. We report that 24hWD from nicotine is associated with altered synaptic expression of VH NRG3 and ERBB4, and genetic disruption of VH ErbB4 leads to an elimination of anxiety-like behaviors induced during 24hWD. Moreover, we observed attenuation of GABAergic transmission as well as alterations in Ca2+-dependent network activity in the ventral CA1 area of VH ErbB4 knock-down mice during 24hWD. Our findings further highlight contributions of the NRG3-ERBB4 signaling pathway to anxiety-related behaviors seen during nicotine WD.

Current Place of SGLT2i in the Management of Heart Failure: An Expert Opinion from India

Heart failure (HF) is a global health concern that is prevalent in India as well. HF is reported at a younger age in Indian patients with comorbidity of type 2 diabetes (T2DM) in approximately 50% of patients. Sodium-glucose cotransporter-2 inhibitors (SGLT2i), originally approved for T2DM, are new guideline-recommended and approved treatment strategies for HF. Extensive evidence highlights that SGLT2i exhibits profound cardiovascular (CV) benefits beyond glycemic control. SGLT2i, in conjunction with other guideline-directed medical therapies (GMDT), has additive effects in improving heart function and reducing adverse HF outcomes. The benefits of SGLT2i are across a spectrum of patients, with and without diabetes, suggesting their potential place in broader HF populations irrespective of ejection fraction (EF). This consensus builds on the updated evidence of the efficacy and safety of SGLT2i in HF and recommends its place in therapy with a focus on Indian patients with HF.

Role of Bisoprolol in Heart Failure Management: A Consensus Statement from India

In India, heart failure (HF) is an important health concern affecting younger age groups than the western population. A limited number of Indian patients receive guideline-directed medical therapy (GDMT). Selective β-1 blockers (BB) are one of the GDMTs in HF and play an important role by decreasing the sympathetic overdrive. The BB reduces heart rate (HR) reverse the adverse cardiac (both ventricular and atrial), vascular, and renovascular remodeling seen in HF. Bisoprolol, a β-1 blocker, has several advantages and can be used across a wide spectrum of HF presentations and in patients with HF and comorbid conditions such as coronary artery disease (CAD), atrial fibrillation (AF), post-myocardial infarction (MI), uncontrolled diabetes, uncontrolled hypertension, and renal impairment. Despite its advantages, bisoprolol is not optimally utilized for managing HF in India. This consensus builds on updated evidence on the efficacy and safety of bisoprolol in HF and recommends its place in therapy with a focus on Indian patients with HF.

Environmental Consequences of Intensive Aquaculture Practices at Moyna Purba Medinipur West Bengal India with Special Reference to Carbon Footprint and Carbon Sequestration

Moyna of Purba Medinipur district is widely known as an aquaculture hub of West Bengal, India. Though very good production is achievable from this fish culture system, management practices are inappropriate, which could create the sustainability problem of this culture system. The present study was thus undertaken for the estimation of plankton population, water quality, carbon footprint and carbon sequestration of this intensive aquaculture practices. Information on spawn to fry, fry to fingerlings and grow-out culture were collected through the structured questionnaire from the fish farmers. The plankton density, primary productivity, carbon footprint and carbon sequestration were analyzed using standard procedures. The phytoplankton, zooplankton and primary productivity were maximum at the stocking period and minimum during the middle of culture period. The lowest feed conversion ratio (FCR) was noticed with the minimum amount of feed applied in the pond. The CO2-e emission ranged from 0.56 to 4.89 kg CO2-e/kg fish (av. 2.13) for the production levels of 5.0 to 10.7 t/ha/yr. The pond water developed salinity and ammonium-N increased from 0.01 to 0.50 mg/l. The ponds with high feed loading (28 to 32 t/ha/yr) had the highest average sediment accumulation rate (11.0 ± 3.0 cm/yr) and carbon sequestration (704 ± 30 g C/m2/yr).

PTBP1 regulates injury responses and sensory pathways in adult peripheral neurons

Polypyrimidine tract binding protein 1 (PTBP1) is thought to be expressed only at embryonic stages in central neurons. Its down-regulation triggers neuronal differentiation in precursor and non-neuronal cells, an approach recently tested for generation of neurons de novo for amelioration of neurodegenerative disorders. Moreover, PTBP1 is replaced by its paralog PTBP2 in mature central neurons. Unexpectedly, we found that both proteins are coexpressed in adult sensory and motor neurons, with PTBP2 restricted mainly to the nucleus, while PTBP1 also shows axonal localization. Levels of axonal PTBP1 increased markedly after peripheral nerve injury, and it associates in axons with mRNAs involved in injury responses and nerve regeneration, including importin β1 (KPNB1) and RHOA. Perturbation of PTBP1 affects local translation in axons, nociceptor neuron regeneration and both thermal and mechanical sensation. Thus, PTBP1 has functional roles in adult axons. Hence, caution is required before considering targeting of PTBP1 for therapeutic purposes.

Dynamic Effects of Ventral Hippocampal NRG3/ERBB4 Signaling on Nicotine Withdrawal-Induced Responses

Tobacco smoking remains a leading cause of preventable death in the United States, with a less than 5% success rate for smokers attempting to quit. High relapse rates have been linked to several genetic factors, indicating that the mechanistic relationship between genes and drugs of abuse is a valuable avenue for the development of novel smoking cessation therapies. For example, various single nucleotide polymorphisms (SNPs) in the gene for neuregulin 3 (NRG3) and its cognate receptor, the receptor tyrosine-protein kinase erbB-4 (ERBB4), have been linked to nicotine addiction. Our lab has previously shown that ERBB4 plays a role in anxiety-like behavior during nicotine withdrawal (WD); however, the neuronal mechanisms and circuit-specific effects of NRG3-ERBB4 signaling during nicotine and WD are unknown. The present study utilizes genetic, biochemical, and functional approaches to examine the anxiety-related behavioral and functional role of NRG3-ERBB4 signaling, specifically in the ventral hippocampus (VH). We report that 24hWD from nicotine is associated with altered synaptic expression of VH NRG3 and ERBB4, and genetic disruption of VH ErbB4 leads to an elimination of anxiety-like behaviors induced during 24hWD. Moreover, we observed attenuation of GABAergic transmission as well as alterations in Ca2+-dependent network activity in the ventral CA1 area of VH ErbB4 knock-down mice during 24hWD. Our findings further highlight contributions of the NRG3-ERBB4 signaling pathway to anxiety-related behaviors seen during nicotine WD.

Profiling Locally Translated mRNAs in Regenerating Axons

Spatial and temporal regulation of protein expression plays important roles in many cellular functions, particularly for highly polarized cell types. While the subcellular proteome can be altered by relocalizing proteins from other domains of the cell, transporting mRNAs to subcellular domains provides a means to locally synthesize new proteins in response to different stimuli. Localized protein synthesis is a critical mechanism in neurons that extend dendrites and axons long distances from their cell bodies. Here, we discuss methodologies that have been developed to study localized protein synthesis using axonal protein synthesis as an example. We provide an in-depth method using dual fluorescence recovery after photobleaching to visualize sites of protein synthesis using reporter cDNAs that encode two different localizing mRNAs along with diffusion-limited fluorescent reporter proteins. We show how this method can be used to determine how extracellular stimuli and different physiological states can alter the specificity of local mRNA translation in real time.

Nanoparticle Mediated Gene Therapy: A Trailblazer Armament to Fight CNS Disorders

Central nervous system (CNS) disorders account for boundless socioeconomic burdens with devastating effects among the population, especially the elderly. The major symptoms of these disorders are neurodegeneration, neuroinflammation, and cognitive dysfunction caused by inherited genetic mutations or by genetic and epigenetic changes due to injury, environmental factors, and disease-related events. Currently available clinical treatments for CNS diseases, i.e., Alzheimer's disease, Parkinson's disease, stroke, and brain tumor, have significant side effects and are largely unable to halt the clinical progression. So gene therapy displays a new paradigm in the treatment of these disorders with some modalities, varying from the suppression of endogenous genes to the expression of exogenous genes. Both viral and non-viral vectors are commonly used for gene therapy. Viral vectors are quite effective but associated with severe side effects, like immunogenicity and carcinogenicity, and poor target cell specificity. Thus, non-viral vectors, mainly nanotherapeutics like nanoparticles (NPs), turn out to be a realistic approach in gene therapy, achieving higher efficacy. NPs demonstrate a new avenue in pharmacotherapy for the delivery of drugs or genes to their selective cells or tissue, thus providing concentrated and constant drug delivery to targeted tissues, minimizing systemic toxicity and side effects. The current review will emphasize the role of NPs in mediating gene therapy for CNS disorders treatment. Moreover, the challenges and perspectives of NPs in gene therapy will be summarized.

Intra-axonal translation of Khsrp mRNA slows axon regeneration by destabilizing localized mRNAs

Axonally synthesized proteins support nerve regeneration through retrograde signaling and local growth mechanisms. RNA binding proteins (RBP) are needed for this and other aspects of post-transcriptional regulation of neuronal mRNAs, but only a limited number of axonal RBPs are known. We used targeted proteomics to profile RBPs in peripheral nerve axons. We detected 76 proteins with reported RNA binding activity in axoplasm, and levels of several change with axon injury and regeneration. RBPs with altered levels include KHSRP that decreases neurite outgrowth in developing CNS neurons. Axonal KHSRP levels rapidly increase after injury remaining elevated up to 28 days post axotomy. Khsrp mRNA localizes into axons and the rapid increase in axonal KHSRP is through local translation of Khsrp mRNA in axons. KHSRP can bind to mRNAs with 3'UTR AU-rich elements and targets those transcripts to the cytoplasmic exosome for degradation. KHSRP knockout mice show increased axonal levels of KHSRP target mRNAs, Gap43, Snap25, and Fubp1, following sciatic nerve injury and these mice show accelerated nerve regeneration in vivo. Together, our data indicate that axonal translation of the RNA binding protein Khsrp mRNA following nerve injury serves to promote decay of other axonal mRNAs and slow axon regeneration.

Hypertension in Young Adults in India: Perspectives and Therapeutic Options amongst Clinician's in a Cross Sectional Observational Study

BACKGROUND

The prevalence of hypertension in the young adult population is rising in India. Increased arterial stiffness due to RAAS activation and increased sympathetic overactivity due to stress have been implicated as primary factors for the same. This study was aimed to understand the Indian clinician's perspective on approach to management of hypertension in young adults.

METHODS

A cross sectional observational survey using a structured questionnaire was conducted online with 2287clinicians (cardiologists, diabetologists, consultant physicians and family physicians).

RESULTS

The prevalence of hypertension was 10-30% as per opinion of 64.8% clinicians. The top three risk factors for hypertension in young were perceived to be smoking, mental stress and obesity. Around 57.4% respondents opined that both increased heart rate and systolic blood pressure were markers of sympathetic overactivity. More than 60% respondents across specialities preferred ARBs to treat hypertension in young adults. Amongst the ARBs, telmisartan was the preferred ARB by >80% respondents. Metoprolol was the preferred beta blocker by almost 64% respondents. The objective of selection of beta-blocker by majority of clinicians due to sympathetic overactivity. Telmisartan and Metoprolol single pill combination achieved the BP goal in 40-60% of patients as reported by 41.3% of the physicians. The combination therapy was well tolerated in young hypertensive patients.

CONCLUSIONS

Initiation of an early and appropriate antihypertensive treatment in young population may lower the burden of cardiovascular disease in this population. ARBs and beta -blockers were the preferred class of anti-hypertensive drugs in the cohort of young hypertensive patients .

The glycine arginine-rich domain of the RNA-binding protein nucleolin regulates its subcellular localization

Nucleolin is a multifunctional RNA Binding Protein (RBP) with diverse subcellular localizations, including the nucleolus in all eukaryotic cells, the plasma membrane in tumor cells, and the axon in neurons. Here we show that the glycine arginine rich (GAR) domain of nucleolin drives subcellular localization via protein-protein interactions with a kinesin light chain. In addition, GAR sequences mediate plasma membrane interactions of nucleolin. Both these modalities are in addition to the already reported involvement of the GAR domain in liquid-liquid phase separation in the nucleolus. Nucleolin transport to axons requires the GAR domain, and heterozygous GAR deletion mice reveal reduced axonal localization of nucleolin cargo mRNAs and enhanced sensory neuron growth. Thus, the GAR domain governs axonal transport of a growth controlling RNA-RBP complex in neurons, and is a versatile localization determinant for different subcellular compartments. Localization determination by GAR domains may explain why GAR mutants in diverse RBPs are associated with neurodegenerative disease.

Neurobiology: Resetting the axon's batteries

Neuronal injury can cause mitochondrial damage, leading to reduced energy production, decreased Ca²⁺ storage capacity, and increased reactive oxygen species. A new study reveals a mechanism to trigger the axonal transport of previously anchored mitochondria and promote neuroprotection and axon regeneration by replacing damaged with functional mitochondria.

Age-related loss of axonal regeneration is reflected by the level of local translation

Regeneration capacity is reduced as CNS axons mature. Using laser-mediated axotomy, proteomics and puromycin-based tagging of newly-synthesized proteins in a human embryonic stem cell-derived neuron culture system that allows isolation of axons from cell bodies, we show here that efficient regeneration in younger axons (d45 in culture) is associated with local axonal protein synthesis (local translation). Enhanced regeneration, promoted by co-culture with human glial precursor cells, is associated with increased axonal synthesis of proteins, including those constituting the translation machinery itself. Reduced regeneration, as occurs with the maturation of these axons by d65 in culture, correlates with reduced levels of axonal proteins involved in translation and an inability to respond by increased translation of regeneration promoting axonal mRNAs released from stress granules. Together, our results provide evidence that, as in development and in the PNS, local translation contributes to CNS axon regeneration.

Selective axonal translation of the mRNA isoform encoding prenylated Cdc42 supports axon growth

The small Rho-family GTPase Cdc42 has long been known to have a role in cell motility and axon growth. The eukaryotic Ccd42 gene is alternatively spliced to generate mRNAs with two different 3' untranslated regions (UTRs) that encode proteins with distinct C-termini. The C-termini of these Cdc42 proteins include CaaX and CCaX motifs for post-translational prenylation and palmitoylation, respectively. Palmitoyl-Cdc42 protein was previously shown to contribute to dendrite maturation, while the prenyl-Cdc42 protein contributes to axon specification and its mRNA was detected in neurites. Here, we show that the mRNA encoding prenyl-Cdc42 isoform preferentially localizes into PNS axons and this localization selectively increases in vivo during peripheral nervous system (PNS) axon regeneration. Functional studies indicate that prenyl-Cdc42 increases axon length in a manner that requires axonal targeting of its mRNA, which, in turn, needs an intact C-terminal CaaX motif that can drive prenylation of the encoded protein. In contrast, palmitoyl-Cdc42 has no effect on axon growth but selectively increases dendrite length. Together, these data show that alternative splicing of the Cdc42 gene product generates an axon growth promoting, locally synthesized prenyl-Cdc42 protein. This article has an associated First Person interview with one of the co-first authors of the paper.

Fabrication of TiO2-based broadband single-layer anti-reflection coating by collimated glancing angle deposition technique

Single-sided TiO2 thin films were prepared using a modified glancing angle deposition (GLAD) technique. An additional flux collimation plate was introduced into the GLAD arrangement to enhance the degree of collimation of depositing vapour flux. Enhancement in the ballistic growth of film on the substrate was observed with increasing distance from the vapour source. The substrate position near to the vapour source (i.e. bottom region) showed a high refractive index (RI, ∼1.336 @ 550 nm wavelength) and lower average film transmittance (∼94.5% in 400-900 nm wavelength range) compared to the others. In contrast, the TiO2 coating deposited at a distant position from the source (i.e. top region) showed a remarkably low RI (∼1.190 @ 550 nm wavelength) and excellent anti-reflection over a broad spectral region with a maximum average transmittance (∼95.3% in 400-900 nm wavelength) compared to the other substrate positions. The reduction in film RI was correlated qualitatively with the morphological alterations in the coating for different substrate positions. With a further increase in distance from the vapour source, an ultimate reduction in the RI of TiO2 to ∼1.101 was observed, which was ∼50% lower than the bulk TiO2 value (∼2.221 @ 550 nm wavelength). The present study reports the lowest RI of TiO2 together with fabrication of a TiO2-based broadband single-layer anti-reflection coating.

Liposomes: Novel Drug Delivery Approach for Targeting Parkinson's Disease

Parkinson's disease is one of the most severe progressive neurodegenerative disorders, having a mortifying effect on the health of millions of people around the globe. The neural cells producing dopamine in the substantia nigra of the brain die out. This leads to symptoms like hypokinesia, rigidity, bradykinesia, and rest tremor. Parkinsonism cannot be cured, but the symptoms can be reduced with the intervention of medicinal drugs, surgical treatments, and physical therapies. Delivering drugs to the brain for treating Parkinson's disease is very challenging. The blood-brain barrier acts as a highly selective semi-permeable barrier, which refrains the drug from reaching the brain. Conventional drug delivery systems used for Parkinson's disease do not readily cross the blood barrier and further lead to several side-effects. Recent advancements in drug delivery technologies have facilitated drug delivery to the brain without flooding the bloodstream and by directly targeting the neurons. In the era of Nanotherapeutics, liposomes are an efficient drug delivery option for brain targeting. Liposomes facilitate the passage of drugs across the blood-brain barrier, enhances the efficacy of the drugs, and minimize the side effects related to it. The review aims at providing a broad updated view of the liposomes, which can be used for targeting Parkinson's disease.

Elucidating the drug repurposing spectra of COVID-19 with its analogues SARS and MERS

COVID-19 disease, caused by the SARS CoV-2 virus, has been announced as Pandemic by the WHO. To date it has affected almost every part of the world, more than 39.8 million people were infected and up to 1.11 million have lost their lives. Currently, there has been no success to develop measures to cure the disease. Additionally, the vaccine development may take several months, and many novel drug molecules attempted have been fallen short of achieving success yet. Hence, an effective alternative solution is a need for these darkest hours. Repurposing of drugs has already proved efficacy in diseases, like, and it significantly provides the most acceptable alternative. There are hundreds of drug molecules approved for clinical trials by the FDA. SARS COV 2 virus has shown resemblance with enzyme targets such as 3CLpro/Mpro, RdRp, Cathepsin L, and TMPRSS2 with SARS CoV and MERS CoV that gives an option to use drugs that have shown efficacy in these viruses for COVID-19 (Corona Virus Disease) treatment. This review focuses on why repurposing could provide a better alternative in COVID-19 treatment and the similarity in the structural and progression of infection of these viruses gives a direction and validation to evaluate the drugs approved for SARS and MERS against COVID-19. It has been indicated that multiple therapeutic options that demonstrate efficacy against SARS CoV 2 are available to mitigate the potential emergence of COVID-19 infection.

Curcumin Loaded Ethosomal Gel for Improved Topical Delivery: Formulation, Characterization and Ex-vivo Studies

BACKGROUND

Curcumin is a curcuminoid which is an active constituent of turmeric and is obtained from the rhizomes of Curcuma longa, family Zingiberaceae. Curcumin modulates the activity of various transcription factors and regulates the expression of inflammatory enzymes, cell survival proteins, adhesion molecules and cytokines by binding to a variety of proteins and inhibiting the activity of various kinases. Curcumin falls in the BCS class IV drug, with poor solubility and poor permeability which makes it very challenging in utilizing the maximum therapeutic potential of this moiety.

OBJECTIVE

The major aim of the study was to enhance transdermal penetration of curcumin via ethosomal gel and to overcome the barriers of poor permeability of transdermal drug delivery.

METHODS

Curcumin loaded ethosomes were prepared with varying quantities of ethanol and soya lecithin by cold method and were optimised based on entrapment efficiency, vesicular size and Ex-vivo studies. Optimised ethosomal formulation was further incorporated into a gel and was evaluated. Ex-vivo studies were performed with the ethosomal gel of curcumin and was compared with simple drug solution.

RESULT

Prepared ethosomal system showed a vesicle size ranging from 211 to 320 nm with spherical, smooth surface and entrapment efficiency of 87 to 91%. Optimised ethosomal system (ET3) was incorporated into gel and was further evaluated.

CONCLUSION

The findings of the research work suggested that the ethosomal gel holds an excellent potential for transdermal delivery of curcumin.

The functional organization of axonal mRNA transport and translation

Axons extend for tremendously long distances from the neuronal soma and make use of localized mRNA translation to rapidly respond to different extracellular stimuli and physiological states. The locally synthesized proteins support many different functions in both developing and mature axons, raising questions about the mechanisms by which local translation is organized to ensure the appropriate responses to specific stimuli. Publications over the past few years have uncovered new mechanisms for regulating the axonal transport and localized translation of mRNAs, with several of these pathways converging on the regulation of cohorts of functionally related mRNAs - known as RNA regulons - that drive axon growth, axon guidance, injury responses, axon survival and even axonal mitochondrial function. Recent advances point to these different regulatory pathways as organizing platforms that allow the axon's proteome to be modulated to meet its physiological needs.

A Ca2+-Dependent Switch Activates Axonal Casein Kinase 2α Translation and Drives G3BP1 Granule Disassembly for Axon Regeneration

The main limitation on axon regeneration in the peripheral nervous system (PNS) is the slow rate of regrowth. We recently reported that nerve regeneration can be accelerated by axonal G3BP1 granule disassembly, releasing axonal mRNAs for local translation to support axon growth. Here, we show that G3BP1 phosphorylation by casein kinase 2α (CK2α) triggers G3BP1 granule disassembly in injured axons. CK2α activity is temporally and spatially regulated by local translation of Csnk2a1 mRNA in axons after injury, but this requires local translation of mTor mRNA and buffering of the elevated axonal Ca²⁺ that occurs after axotomy. CK2α's appearance in axons after PNS nerve injury correlates with disassembly of axonal G3BP1 granules as well as increased phospho-G3BP1 and axon growth, although depletion of Csnk2a1 mRNA from PNS axons decreases regeneration and increases G3BP1 granules. Phosphomimetic G3BP1 shows remarkably decreased RNA binding in dorsal root ganglion (DRG) neurons compared with wild-type and non-phosphorylatable G3BP1; combined with other studies, this suggests that CK2α-dependent G3BP1 phosphorylation on Ser 149 after axotomy releases axonal mRNAs for translation. Translation of axonal mRNAs encoding some injury-associated proteins is known to be increased with Ca²⁺ elevations, and using a dual fluorescence recovery after photobleaching (FRAP) reporter assay for axonal translation, we see that translational specificity switches from injury-associated protein mRNA translation to CK2α translation with endoplasmic reticulum (ER) Ca²⁺ release versus cytoplasmic Ca²⁺ chelation. Our results point to axoplasmic Ca²⁺ concentrations as a determinant for the temporal specificity of sequential translational activation of different axonal mRNAs as severed axons transition from injury to regenerative growth.

Diversity of virulence-associated genes in pathogenic Aeromonas hydrophila isolates and their in vivo modulation at varied water temperatures

Most environmental parameters have no consistent effect on the expression of bacterial genes responsible for their virulence. However, as fish are poikilothermic, the possibility of temperature variation having a pronounced effect on the expression of virulence-associated gene(s) of bacteria infecting the host needs to be investigated. In this study, the diversity of virulence genes in seven Aeromonas hydrophila isolates collected from diseased fish from different parts of India was characterized, and the effect of temperature variation on the extent of expression of their virulence was investigated. All bacterial isolates were screened for a total of nine bacterial virulent genes {aerolysin, hemolysin, cytoen, outer membrane protein TS (Omp TS), elastase, flagellin, lipase, β hemolysin and type 3 secretion system}, and the diversity in their presence or absence were marked at a particular in vitro condition. Three bacterial isolates (nos. 1, 7 and 2) were selected for further study, based on their ability to cause varied mortalities (20-100%) in Labeo rohita juveniles in intraperitoneal challenge study. Further, three isolates were injected intraperitoneally into L. rohita fingerlings at three different temperatures (i.e., 20, 28 and 37 °C) and at 6 h post-challenge, the kidney samples were collected to measure the levels of all nine bacterial virulence genes using semi-quantitative PCR. The maximum level of amplicons of virulence genes in all three A. hydrophila isolates was noticed at 28 °C as compared to 37 °C and 20 °C. It was also observed that haemolysin played a more prominent role in the expression of virulence, when compared to cytoen gene. Hence, it was concluded that water temperature does play a crucial role in governing virulence gene expression, and a temperature of 28 °C would be considered as suitable for looking into the pathogenicity of A. hydrophila for conducting any challenge study with this organism in tropical environment.

Intra-axonal mechanisms driving axon regeneration

Traumatic injury to the peripheral and central nervous systems very often causes axotomy, where an axon loses connections with its target resulting in loss of function. The axon segments distal to the injury site lose connection with the cell body and degenerate. Axotomized neurons in the periphery can spontaneously mount a regenerative response and reconnect to their denervated target tissues, though this is rarely complete in humans. In contrast, spontaneous regeneration rarely occurs after axotomy in the spinal cord and brain. Here, we concentrate on the mechanisms underlying this spontaneous regeneration in the peripheral nervous system, focusing on events initiated from the axon that support regenerative growth. We contrast this with what is known for axonal injury responses in the central nervous system. Considering the neuropathy focus of this special issue, we further draw parallels and distinctions between the injury-response mechanisms that initiate regenerative gene expression programs and those that are known to trigger axon degeneration.

Treatment and management strategies of onychomycosis

Onychomycosis is one of the most prevalent and severe nail fungal infections, which is affecting a wide population across the globe. It leads to variations like nail thickening, disintegration and hardening. Oral and topical drug delivery systems are the most desirable in treating onychomycosis, but the efficacy of the results is low, resulting in a relapse rate of 25-30%. Due to systemic toxicity and various other disadvantages associated with oral therapy like gastrointestinal, hepatotoxicity, topical therapy is commonly used. Topical therapy improves patient compliance and reduces the cost of treatment. However, due to poor penetration of topical therapy across the nail plate, research is focused on different chemical, mechanical and physical methods to improve drug delivery. Penetration enhancers like Thioglycolic acid, Hydroxypropyl-β-cyclodextrin (HP-β-CD), Sodium lauryl sulfate (SLS), carbocysteine, N-acetylcysteine etc. have shown results enhancing the drug penetration across the nail plate. Results with physical techniques such as iontophoresis, laser and Photodynamic therapy are quite promising, but the long-term suitability of these devices is in need to be determined. In this article, a brief analysis of the treatment procedures, factors affecting drug permeation across nail plate, chemical, mechanical and physical devices used to increase the drug delivery through nails for the onychomycosis management has been achieved.

Ultraviolet and Infrared luminescent Au-rich nanostructure growth in SiO2 by burrowing and inverse Oswald ripening process

We study the evolution of nanoparticle morphology through successive stages when Au-Si bilayer on SiO₂ is irradiated with 500 keV Xe-ions and resulting luminescence in the UV, Visible and infrared range. An array of nanoscale island morphology is developed on the silica surface in the initial stage of evolution which undergoes gradual burrowing in the silica matrix accompanied by elongation of large ones in the direction of incident ions under cumulative ion irradiation. Burrowing is found to occur in order to minimize the surface free energy of the nanoparticles. Numerical simulation based on the unified thermal spike model shows formation of molten latent tracks due to ions energy release which drive the dewetting of the metal layer and further give mobility to nanoparticle atoms leading to burrowing in the later stage of evolution and elongation of large nanoparticles. Satellite nanoparticles are observed to grow around Au nanoparticles embedded in silica through nucleation of Au atoms dissolved in the matrix by incident ions. The varying diameters of the Au satellite nanoparticles seem to result in luminescence in the UV and infrared range. The observed structure may find application in surface enhanced Raman scattering, catalysis, and LEDs.

Identification and functional characterization of a g-type lysozyme gene of Labeo rohita, an Indian major carp species

Lysozyme, an important secretory innate immune component, possesses antimicrobial activity against broad spectrum of bacteria and viruses. In the present study, complete CDs (558 bps) of g-type lysozyme of rohu (Labeo rohita) was amplified and translated for a putative protein of 185 amino acids. The domain architecture and tertiary structure was also predicted for the protein. Its expression profile was studied in three infection models (bacteria: Aeromonas hydrophila, poly I:C, a dsRNA viral analogue and an ectoparasite: Argulus siamensis) in liver and kidney tissues of rohu. An up-regulation of 630-fold and 420-fold of the gene was observed at 48 h in liver and anterior kidney tissues respectively, after A. hydrophila infection. Significant increase in transcript level was noticed in both liver (0.8-fold) and kidney (480-fold) after 1 h and 12 h of poly I:C induction, respectively. Similarly, expression of lysozyme g transcripts was increased 6000-fold after 7 d of A. siamensis infection in liver tissue. The recombinant protein of g-type lysozyme of rohu (rLr-lysG) of 20.19 kDa was produced in Escherichia coli system and the lysozyme activity of rLr-lysG was found to be most active at pH 6.0 and temperature 35 °C. The potential lytic activity was found to be against A. hydrophila (U_L = 0.53) followed by for E. tarda (U_L = 0.45) whereas the lytic activity was the least against S. aureus (U_L = 0.35) and M. lysodeikticus (U_L = 0.34), at pH 6.0 and temperature 35 °C. The normal serum level of protein was estimated using indirect ELISA and was found to be very low (0.12-0.15 μg/ml). These results suggested that g-type lysozyme of rohu might be a potent immunostimulant against microbial infections, with a major role in innate immunity.

Axonal G3BP1 stress granule protein limits axonal mRNA translation and nerve regeneration

Critical functions of intra-axonally synthesized proteins are thought to depend on regulated recruitment of mRNA from storage depots in axons. Here we show that axotomy of mammalian neurons induces translation of stored axonal mRNAs via regulation of the stress granule protein G3BP1, to support regeneration of peripheral nerves. G3BP1 aggregates within peripheral nerve axons in stress granule-like structures that decrease during regeneration, with a commensurate increase in phosphorylated G3BP1. Colocalization of G3BP1 with axonal mRNAs is also correlated with the growth state of the neuron. Disrupting G3BP functions by overexpressing a dominant-negative protein activates intra-axonal mRNA translation, increases axon growth in cultured neurons, disassembles axonal stress granule-like structures, and accelerates rat nerve regeneration in vivo.

G3BP1 is RasGAP SH3 domain binding protein 1 that interacts with 48S pre-initiation complex when translation is stalled. Here, Twiss and colleagues show that neuronal G3BP1 can negatively regulate axonal mRNA translation, and inhibit axonal regeneration after injury.

hnRNPs Interacting with mRNA Localization Motifs Define Axonal RNA Regulons

mRNA translation in axons enables neurons to introduce new proteins at sites distant from their cell body. mRNA-protein interactions drive this post-transcriptional regulation, yet knowledge of RNA binding proteins (RBP) in axons is limited. Here we used proteomics to identify RBPs interacting with the axonal localizing motifs of Nrn1, Hmgb1, Actb, and Gap43 mRNAs, revealing many novel RBPs in axons. Interestingly, no RBP is shared between all four RNA motifs, suggesting graded and overlapping specificities of RBP-mRNA pairings. A systematic assessment of axonal mRNAs interacting with hnRNP H1, hnRNP F, and hnRNP K, proteins that bound with high specificity to Nrn1 and Hmgb1, revealed that axonal mRNAs segregate into axon growth-associated RNA regulons based on hnRNP interactions. Axotomy increases axonal transport of hnRNPs H1, F, and K, depletion of these hnRNPs decreases axon growth and reduces axonal mRNA levels and axonal protein synthesis. Thus, subcellular hnRNP-interacting RNA regulons support neuronal growth and regeneration.

Axonal mRNA transport and translation at a glance

Localization and translation of mRNAs within different subcellular domains provides an important mechanism to spatially and temporally introduce new proteins in polarized cells. Neurons make use of this localized protein synthesis during initial growth, regeneration and functional maintenance of their axons. Although the first evidence for protein synthesis in axons dates back to 1960s, improved methodologies, including the ability to isolate axons to purity, highly sensitive RNA detection methods and imaging approaches, have shed new light on the complexity of the transcriptome of the axon and how it is regulated. Moreover, these efforts are now uncovering new roles for locally synthesized proteins in neurological diseases and injury responses. In this Cell Science at a Glance article and the accompanying poster, we provide an overview of how axonal mRNA transport and translation are regulated, and discuss their emerging links to neurological disorders and neural repair.

Locally translated mTOR controls axonal local translation in nerve injury

How is protein synthesis initiated locally in neurons? We found that mTOR (mechanistic target of rapamycin) was activated and then up-regulated in injured axons, owing to local translation of mTOR messenger RNA (mRNA). This mRNA was transported into axons by the cell size-regulating RNA-binding protein nucleolin. Furthermore, mTOR controlled local translation in injured axons. This included regulation of its own translation and that of retrograde injury signaling molecules such as importin β1 and STAT3 (signal transducer and activator of transcription 3). Deletion of the mTOR 3' untranslated region (3'UTR) in mice reduced mTOR in axons and decreased local translation after nerve injury. Both pharmacological inhibition of mTOR in axons and deletion of the mTOR 3'UTR decreased proprioceptive neuronal survival after nerve injury. Thus, mRNA localization enables spatiotemporal control of mTOR pathways regulating local translation and long-range intracellular signaling.

A study of electron and thermal transport in layered titanium disulphide single crystals

We present a detailed study of thermal and electrical transport behavior of single crystal titanium disulphide flakes, which belong to the two dimensional, transition metal dichalcogenide class of materials. In-plane Seebeck effect measurements revealed a typical metal-like linear temperature dependence in the range of 85-285 K. Electrical transport measurements with in-plane current geometry exhibited a nearly T ² dependence of resistivity in the range of 42-300 K. However, transport measurements along the out-of-plane current geometry showed a transition in temperature dependence of resistivity from T ² to T ⁵ beyond 200 K. Interestingly, Au ion-irradiated TiS₂ samples showed a similar T ⁵ dependence of resistivity beyond 200 K, even in the current-in-plane geometry. Micro-Raman measurements were performed to study the phonon modes in both pristine and ion-irradiated TiS₂ crystals.

Axonal localization of neuritin/CPG15 mRNA is limited by competition for HuD binding

HuD protein (also known as ELAVL4) has been shown to stabilize mRNAs with AU-rich elements (ARE) in their 3' untranslated regions (UTRs), including Gap43, which has been linked to axon growth. HuD also binds to neuritin (Nrn1) mRNA, whose 3'UTR contains ARE sequences. Although the Nrn1 3'UTR has been shown to mediate its axonal localization in embryonic hippocampal neurons, it is not active in adult dorsal root ganglion (DRG) neurons. Here, we asked why the 3'UTR is not sufficient to mediate the axonal localization of Nrn1 mRNA in DRG neurons. HuD overexpression increases the ability of the Nrn1 3'UTR to mediate axonal localizing in DRG neurons. HuD binds directly to the Nrn1 ARE with about a two-fold higher affinity than to the Gap43 ARE. Although the Nrn1 ARE can displace the Gap43 ARE from HuD binding, HuD binds to the full 3'UTR of Gap43 with higher affinity, such that higher levels of Nrn1 are needed to displace the Gap43 3'UTR. The Nrn1 3'UTR can mediate a higher level of axonal localization when endogenous Gap43 is depleted from DRG neurons. Taken together, our data indicate that endogenous Nrn1 and Gap43 mRNAs compete for binding to HuD for their axonal localization and activity of the Nrn1 3'UTR.

Fermi energy dependence of the optical emission in core/shell InAs nanowire homostructures

InAs nanowires grown by vapor-liquid-solid (VLS) method are investigated by photoluminescence. We observe that the Fermi energy of all samples is reduced by ∼20 meV when the size of the Au nanoparticle used for catalysis is increased from 5 to 20 nm. Additional capping with a thin InP shell enhances the optical emission and does not affect the Fermi energy. The unexpected behavior of the Fermi energy is attributed to the differences in the residual donor (likely carbon) incorporation in the axial (low) and lateral (high incorporation) growth in the VLS and vapor-solid (VS) methods, respectively. The different impurity incorporation rate in these two regions leads to a core/shell InAs homostructure. In this case, the minority carriers (holes) diffuse to the core due to the built-in electric field created by the radial impurity distribution. As a result, the optical emission is dominated by the core region rather than by the more heavily doped InAs shell. Thus, the photoluminescence spectra and the Fermi energy become sensitive to the core diameter. These results are corroborated by a theoretical model using a self-consistent method to calculate the radial carrier distribution and Fermi energy for distinct diameters of Au nanoparticles.

AN ADVANCED CATARACT SURGERY BY PHACOEMULSIFICATION: AN INITIAL EXPERIENCE

Phacoemulsification surgery is rapidly emerging as accepted latest surgical technique for the management of cataract. Retrospective analysis of first fifty cases of phacoemulsification surgery performed in our setup were critically evaluated to assess efficacy and adaptability of this procedure in Armed Forces setup. Results of initial twenty five cases were compared qualitatively with subsequent cases. Equipment settings, operative constraints, post-operative complications, effects on induced astigmatism, visual outcome and patient's rehabilitation were critically evaluated. Corneal striate, iris chaffing, posterior capsular rent were noted initial problems. Induced astigmatism was ranging between 0.5 to 1.0 Dioptre with early decay and complete stabilisation within four weeks. Inspite of excellent visual outcome, complex technique, steep and long learning curve restricts its application to institutional setup.

Ion induced dewetting of Au-Si on a SiO2 surface: composite nanodot evolution and wettability transition

A nanodot array morphology gradually develops on SiO₂ surface when a thin bi-layer of Au and Si undergoes ion irradiation. An increasing amount of gold silicide is detected as islands on the insulator surface evolve into nanodots as a function of increasing ion fluence. Different stages of evolution from islands to nanodots are found to be driven by the localized melting of Au along the ion-track and dewetting of the metal film. Dewetting is accompanied by sputter-erosion and mixing of Au and Si at the bi-layer interface due to ion energy deposition. Interestingly, a gradual transition in wettability of the surface from the hydrophilic to the hydrophobic one is observed with the growth of nanodots, which is correlated with the compositional variation. The experimental results indicate a route towards the controlled growth of composite nanodots on an insulator surface having hydrophobic properties using ion irradiation.

Nucleolin-Mediated RNA Localization Regulates Neuron Growth and Cycling Cell Size

How can cells sense their own size to coordinate biosynthesis and metabolism with their growth needs? We recently proposed a motor-dependent bidirectional transport mechanism for axon length and cell size sensing, but the nature of the motor-transported size signals remained elusive. Here, we show that motor-dependent mRNA localization regulates neuronal growth and cycling cell size. We found that the RNA-binding protein nucleolin is associated with importin β1 mRNA in axons. Perturbation of nucleolin association with kinesins reduces its levels in axons, with a concomitant reduction in axonal importin β1 mRNA and protein levels. Strikingly, subcellular sequestration of nucleolin or importin β1 enhances axonal growth and causes a subcellular shift in protein synthesis. Similar findings were obtained in fibroblasts. Thus, subcellular mRNA localization regulates size and growth in both neurons and cycling cells.

Apolipoprotein A-I in Labeo rohita: Cloning and functional characterisation reveal its broad spectrum antimicrobial property, and indicate significant role during ectoparasitic infection

Apolipoprotein A-I (ApoA-I) is the most abundant and multifunctional high-density lipoprotein (HDL) having a major role in lipid transport and potent antimicrobial activity against a wide range of microbes. In this study, a complete CDS of 771 bp of Labeo rohita (rohu) ApoA-I (LrApoA-I) encoding a protein of 256 amino acids was amplified, cloned and sequenced. Tissue specific transcription analysis of LrApoA-I revealed its expression in a wide range of tissues, with a very high level of expression in liver and spleen. Ontogenic study of LrApoA-I expression showed presence of transcripts in milt and 3 h post-fertilization onwards in the larvae. The expression kinetics of LrApoA-I was studied upon infection with three different types of pathogens to elucidate its functional significance. Its expression was found to be up-regulated in the anterior kidney of L. rohita post-infection with Aeromonas hydrophila. Similarly following poly I:C (poly inosinic:cytidylic) stimulation, the transcript levels increased in both the anterior kidney and liver tissues. Significant up-regulation of LrApoA-I expression was observed in skin, mucous, liver and anterior kidney of the fish challenged with the ectoparasite Argulus siamensis. Immunomodulatory effect of recombinant LrApoA-I (rApoA-I) produced in Escherichia coli was demonstrated against A. hydrophila challenge in vivo. L. rohita administered with rApoA-I at a dose of 100 μg exhibited significantly higher protection (∼55%) upon challenge with A. hydrophila 12 h post-administration of the protein, in comparison to that observed in control group, along with higher level of expression of immune-related genes. The heightened expression of ApoA-I observed post-infection reflected its involvement in immune responses against a wide range of infections including bacterial, viral as well as parasitic pathogens. Our results also suggest the possibility of using rApoA-I as an immunostimulant, particularly rendering protection against A. hydrophila.

Four pro-inflammatory cytokines of rohu (Labeo rohita) during early developmental stages, their tissue distribution and expression by leucocytes upon in-vitro stimulation

Cytokines are important components of both adaptive and innate immunity, and are required to initiate and regulate immune responses following infection. The ontogeny and tissue specific distribution of four pro-inflammatory cytokines, interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), IL-8 and IL-1β in rohu (Labeo rohita), and their responses by leucocytes from anterior-kidney/head-kidney (HKLs), spleen (SPLs) and peripheral blood (PBLs) following stimulation with concanavalin A (ConA), ConA with phorbol 12-myristate 13-acetate (ConA/PMA) and formalin-killed Aeromonas hydrophila cells (FAH) were studied. In ontogeny study, mRNA levels of IL-6 and IL-1β were evident in unfertilized egg stages of L. rohita whereas IL-8 and TNF-α transcripts were found from 1 to 3 h post-fertilization (hpf) onwards till day 15 post-fertilization, respectively. Basal level of all four cytokines was observed in all twelve tissues (eye, brain, heart, gill, anterior kidney, posterior kidney, spleen, liver, skin, muscle, hindgut and foregut) of L. rohita juveniles. Expression levels of IL-6 and IL-8 were found to be the highest in liver and heart tissues, respectively, while TNF-α transcripts were high in anterior kidney and liver tissues. Transcripts of IL-1β showed high expression in muscle, heart and spleen. Upon in vitro stimulation of leucocytes, there was variable up-regulation of all the four cytokines following different treatments throughout the experimental time period. Induction of cytokines was more pronounced in PBLs stimulated with FAH compared to other stimuli. However, an up-regulated IL-8 expression was evident in all the leucocytes following stimulation with FAH thus indicating IL-8 could be used as an indicator or indirect marker to monitor vaccine status or health status of L. rohita during bacterial infection.

Molecular characterization of interleukin 15 mRNA from rohu, Labeo rohita (Hamilton): Its prominent role during parasitic infection as indicated from infection studies

Interleukin 15 (IL-15) is an important cytokine of fish immune system. Sequence characterization of IL-15 from rohu, Labeo rohita revealed a mRNA sequence of 1064 bp with coding sequence of 567 bp and signal peptide of 16 amino acids. There are four characteristic sequence features viz., presence of four out-of-frame AUG initiation codons, four highly conserved cysteine residues, constitutive expression in all tissues and evolutionary similarity. The ontogeny study revealed maternal transfer of this molecule and higher expression up to 3 h post-fertilization in fertilized embryos. Its expression was down-regulated in anterior and posterior kidneys, intestine and liver tissues of rohu infected with Aeromonas hydrophila. Mild up-regulation in liver and higher expression in spleen was noticed in rohu stimulated with poly I:C (poly ionosinic:cytidylic), whereas down-regulation was observed in intestine and kidney tissues. However, a consistent higher expression was noticed in kidney and skin tissues during Argulus siamensis infection. Therefore, rohu IL-15 might possess more defensive role during early development and parasitic infection.

Epidemiological study of canine parvovirus infection in and around Bhubaneswar, Odisha, India

Aim:

An epidemiological study of canine parvovirus infection in dogs in and around Bhubaneswar, Odisha was conducted between December 2012 to March 2013 and prevalence rate was studied on the basis of age, breed, and sex.

Materials and Methods:

A total of 71 fecal samples from suspected diarrheic dogs were collected in sterile phosphate buffer saline (10% W/V) and examined by polymerase chain reaction (PCR) for detection of canine parvo virus infection, followed by epidemiological study in relation to age, breed, and sex.

Results:

Of 71 samples analyzed, 29 (40.85%) were found to be positive by PCR assay. The infection was higher in Deshi/local breeds (34.48%), followed by German shepherd (17.24%), equal incidences in mixed and Labrador retriever (10.34%), Rottweiler and German spitz showed 6.90% each and finally lower incidences in four breeds (3.45%) such as Dalmatians, Nea politan mastiff, Pug and Great Dane. Age-wise prevalence study revealed the infection being more in the age group of 3-6 months (41.37%), followed by equal incidences of 27.59% in 1-3 months and 6-12 months age group, and a low incidence in age groups above 12 months (3.45%). The incidence was predominantly higher in males (86.21%) than females (13.79%).

Conclusions:

The epidemiological analysis revealed that the breed wise prevalence was found to be more in Deshi breeds as compared to others, age groups below 6 months were found to be more prone to parvovirus infection and males were mostly infected.

Immune responses and protective efficacy of recombinant outer membrane protein R (rOmpR)-based vaccine of Aeromonas hydrophila with a modified adjuvant formulation in rohu (Labeo rohita)

Despite the importance and success of developing a candidate vaccine against Aeromonas hydrophila infection in fish, little is known about the molecular mechanisms of the vaccine-induced immunoprotection in Indian major carp, Labeo rohita, primarily due to lack of information on most of the immune related genes of the species. In this study, a novel candidate antigen recombinant outer membrane protein R (rOmpR) of A. hydrophila was evaluated as a vaccine candidate along with a modified adjuvant formulation. Protective efficacy of the rOmpR immunization was assessed in terms of survival against A. hydrophila challenge as well as modulation of immune response in vaccinated fish after 1, 3, 6, 12, 24, 72 h and 10 days post-injection (using immune gene expression analysis) and 10, 28, 56 and 140 days post-injection (serum immune parameter analysis). The generated immune response was compared with a formalin-killed A. hydrophila antigen preparation using mineral oil only and modified adjuvant alone. We report a variable up-regulation of the immune-related genes viz., lysozyme G, complement factor 4, immunoglobulin M, β2-microglobulin, major histocompatibility complex I and II, and interleukin-1β in anterior kidney and spleen tissues at early time points post-immunization in all the groups, when compared to the control fish. The vaccinated fish also showed an increase in serum natural hemolysin titer, lysozyme and myeloperoxidase activities, and antibody titer irrespective of vaccine formulations as compared to control fish on days 10, 28 and 56. However, the increase in the serum parameters was more pronounced on day 140 in rOmpR-modified adjuvant injected group, indicating the modulatory role of this new vaccine formulation. Upon challenge with live A. hydrophila on days 56 and 140 post-immunization, significantly reduced percent mortality was noted in the group immunized with modified adjuvant based rOmpR vaccine formulation. Taken together, our results suggest that rOmpR along with modified adjuvant could potentially be used as a vaccine formulation to handle A. hydrophila infection on a long-term basis.

Analysis of immune-related ESTs and differential expression analysis of few important genes in lines of rohu (Labeo rohita) selected for resistance and susceptibility to Aeromonas hydrophila infection

A total of 137,629 contigs generated via de novo transcriptome assembly from resistant and susceptible lines of rohu (first generation) raised against aeromoniasis were further analyzed in terms of defence-related genes. Out of 1,939 contigs showing homology to genes involved in immune processes, 1,866 were further categorised into different functional subgroups. Comparative analysis revealed five genes for the first time in any carp species out of which apolipoprotein h, septin 4 isoform 3 and septin isoform cra_c were identified for the first time in fish. Differential expression analysis of ten genes viz., heat shock proteins (Hsps) (Hsp30, Hsp70 and Hsp90), serum lectin isoform 1 (SLI1), linker histone H1M (LHH1M), NAD(P)H quinone 1 (NQO1), zona pellucida 2 (ZP2) and three unknown genes that were highly up-expressed in first generation resistant line fish from mRNA-seq coverage data, was carried out using susceptible and resistant individuals of the second generation selected populations in eight different tissues viz. liver, kidney, intestine, gill, brain, spleen, skin and muscle using qPCR. Significant up-regulation in Hsp90, NQO1, C_116914 and C_22454 in specific tissues of resistant line and variable expression in Hsp30 and LHH1M genes in different tissues of both lines were noticed. The expression of Hsp70 was lower in many tissues of the resistant line than in susceptible line rohu. The expression of ZP2, SLI1 and C_94589 genes was not significantly different in terms of fold difference between the two lines. Differentially expressed genes need further characterisation to explore their role in resistance to Aeromonas hydrophila infection in rohu.

Effect of Dactylogyrus catlaius (Jain 1961) infection in Labeo rohita (Hamilton 1822): innate immune responses and expression profile of some immune related genes

The monogenean ectoparasite, Dactylogyrus sp. is a major pathogen in freshwater aquaculture. The immune responses in parasitized fish were analyzed by quantitation of innate immune factors (natural agglutinin level, haemolysin titre, antiprotease, lysozyme and myeloperoxidase activities) in serum and immune-relevant gene expression in gill and anterior kidney. The antiprotease activity and natural agglutinin level were found to be significantly higher and lysozyme activity was significantly lower in parasitized fish. Most of the genes viz., beta2-microglobulin (beta2M), major histocompatibility complex I (MHCI), MHCII, tumor necrosis factor alpha (TNFalpha) and toll-like receptor 22 (TLR22) in gill samples were significantly down-regulated in the experimental group. In the anterior kidney, the expression of superoxide dismutase and interleukin 1beta (IL1beta) were significantly up-regulated whereas a significant down regulation of MHCII and TNFalpha was also observed. The down-regulation of most of the genes viz, MHCI, beta2M, MHCII, TLR22 and TNFalpha in infected gills indicated a well evolved mechanism in this parasite to escape the host immune response. The modulation of innate and adaptive immunity by this parasite can be further explored to understand host susceptibility.

Characterization of the ceruloplasmin gene and its potential role as an indirect marker for selection to Aeromonas hydrophila resistance in rohu, Labeo rohita

Ceruloplasmin is an acute phase protein found to be activated by the host immune system during stress conditions. The ceruloplasmin gene has been reported in several teleosts and here we characterize the gene and test its association with resistance to Aeromonas hydrophila in rohu, Labeo rohita. A ceruloplasmin mRNA sequence of 3355 base pairs (bp) was derived (GenBank ID: JX010736). The coding sequence (CDS) comprised of 3276 bp that coded for 1092 amino acids. Alignment results showed the greatest similarity with zebrafish followed by channel catfish sequence, and a phylogenetic tree constructed on the basis of amino acid sequences showed that rohu shares a common clade with these two species. In the ontogeny study, the expression of ceruloplasmin was detected at 9 h post-fertilization onwards, and a strong level of expression was detected at 24 h (38-fold) and 15 days (34-fold) post-fertilization. The ceruloplasmin transcripts were evident in liver, spleen, stomach and heart. Expression was undetectable in gill, brain, eye, skin, muscle, intestine, anterior and posterior kidney tissues. Expression of ceruloplasmin after A. hydrophila infection was up-regulated 6 h post-challenge and was modulated until 15 days post-challenge. The level of ceruloplasmin was also compared in rohu selectively bred for higher growth and disease resistance. The gene showed a 4.58-fold higher level of expression in resistant line over susceptible line rohu selected based on family challenge test survival to A. hydrophila. Serum ceruloplasmin levels in three year classes of rohu selected for higher growth showed a positive correlation (0.49 ± 1.11) with survival against challenge with A. hydrophila. The estimated heritability was also found to be quite high (0.50 ± 0.22) for this parameter. Thus, ceruloplasmin could be one of the useful marker traits for selection against A. hydrophila resistance in fish.

In situ synthesis and properties of reduced graphene oxide/Bi nanocomposites: as an electroactive material for analysis of heavy metals

An in situ modified Hummers method (without the use of any surfactants) has been used for the deposition of bismuth (Bi) nanoparticles onto the surface of reduced graphene oxide (RGO) sheets. The as-synthesized nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, transmission electron microscopy (TEM), thermogravimetry (TG) and differential scanning calorimetry (DSC). The morphology of the RGO/Bi nanocomposites provides a better choice as an electrode material for detection of heavy metal ions due to its better functional properties over the Bi film electrode. Trace analysis of heavy metal ions like Cd(+2), Pb(+2), Cu(+2) and Zn(+2) in water is carried out by stripping voltammetric analysis using RGO/Bi nanocomposite as an electrode material. The sensitivity and detection limit of the electrode were quantitatively estimated from the analysis. The three sigma detection limits at different deposition potential for Cd(2+), Pb(2+), Zn(2+) and Cu(2+) were obtained as 2.8, 0.55, 17 and 26μgL(-1), respectively. Copper detection using Bi-film electrode was a major challenge, which has been resolved using the RGO/Bi nanocomposite electrode.

Viruses of freshwater finfish in the asian-pacific region

There has been a tremendous increase in global demand for marine and freshwater fish to meet the protein needs of our expanding human population. However, due to the limited capacity of the wild-capture sector and a levelling of production from capture fisheries, the practice of farming aquatic animals has expanded rapidly to become a major global industry. Aquaculture, particularly freshwater aquaculture is now integral to the economies of many countries. A large number of aquatic animal species are farmed in high density in freshwater, brackish and marine systems, where they are exposed to new environments and potentially new diseases. Further, environmental stress factors, the use of manufactured feeds, and prolific global trade has led to the emergence and spread of new diseases. Viral pathogens, established for decades or newly emerging as disease threats, are particularly challenging since there are few efficacious treatments. Vaccines have been developed for some viral fish pathogens in salmonids, but vaccines are not available for many of the viral pathogens important in Asia. Control and eradication programs are difficult because many viral infections remain latent until adverse environmental conditions, such as overcrowding or poor water quality, trigger the onset of disease. Here, we review the more significant viral pathogens of finfish in the Asia-Pacific including both those with a long history in Asian aquaculture and emerging pathogens including betanodaviruses and koi herpes virus that have caused massive losses in the freshwater aquaculture and ornamental fish industries.