Silver-deposited titanium as a prophylactic 'nano coat' for peri-implantitis.

Dental implant failures caused by bacterial infections are a significant concern for dental implantologists. We modified the titanium surface by depositing silver (Ti-Ag) using direct current (DC) sputtering and confirmed the formation of a 'nano coat' by X-ray photoelectron spectroscopy (XPS), surface profilometry and energy dispersive spectroscopy (EDS). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed the deposition of a uniform nano Ag thin film. A gradual increase in thickness was observed, and the film thickness (530 nm) at 5 min deposition time (Ti-Ag5) resulted in a reduction of the water contact angle (WCA, 15%) and an increase in surface energy (SFE, 22%) in comparison to the uncoated Ti surface. Using inductively coupled plasma-atomic emission spectroscopy (ICP-AES), the slow, steady release of Ag from the coating was observed over 21 days. The Ti-Ag5 surface exhibited excellent antibacterial activity against Streptococcus oralis, Streptococcus sanguinis, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis, which belonged to the yellow, purple, and red complexes, representing specific periodontal pathogens. Furthermore, we observed excellent cytocompatibility of Ag-deposited Ti towards MG-63 osteoblasts with no inhibitory effect on their proliferative potential. Quantitation of alkaline phosphatase (ALP) activity, mineralization efficiency, and osteogenesis-related gene expression of MG-63 cells over 21 days was suggestive of rapid osseointegration. Overall, the 'nano coat' of Ag on Ti is indeed a prophylactic against peri-implantitis, ensuring increased implant success.

Zinc oxide nanoparticles prevent the onset of diabetic nephropathy by inhibiting multiple pathways associated with oxidative stress.

BACKGROUND: Zinc deficiency is strongly correlated with prolonged diabetes mellitus and diabetic nephropathy (DN). Previously, glucose-lowering, insulinomimetic, and ß-cell proliferative activities of zinc oxide nanoparticles (ZON) have been reported. Considering these pleiotropic effects, we hypothesized that ZON modulates multiple cellular pathways associated with necroptosis, inflammation, and renal fibrosis, which are involved in progressive loss of renal function. AIM: This study evaluated the effect of ZON on renal function, leading to the alleviation of DN in streptozotocin (STZ)-induced type 1 diabetic Wistar rats and proposed a probable mechanism for its activity. METHODS: Wistar rats (n = 6/group) were used as healthy controls, diabetic controls, diabetic rats treated with ZON (1, 3, and 10 mg/kg), and insulin controls. Urine and serum biochemical parameters, glomerular filtration rate (GFR), and renal histology were also evaluated. Cultured E11 podocytes were evaluated in vitro for markers of oxidative stress, proteins associated with the loss of renal function, and genes associated with renal damage. KEY FINDINGS: STZ-treated rats receiving oral doses of ZON showed enhanced renal function, with no histological alterations in the kidney tissue. ZON inhibited the TGF-ß/Samd3 pathway in renal fibrosis; blocked Ripk1/Ripk3/Mlkl mediated necroptosis and protected against hyperglycemia-induced pyroptosis. In E11 podocytes, ZON reduced oxidative stress under high glucose conditions and retained podocyte-specific proteins. SIGNIFICANCE: A probable mechanism by which ZON prevents DN has been proposed, suggesting its use as a complementary therapeutic agent for the treatment of diabetic complications. To the best of our knowledge, this is the first study to demonstrate the in vitro effects of ZON in cultured podocytes.

Enhanced antibacterial activity and superior biocompatibility of cobalt-deposited titanium discs for possible use in implant dentistry.

The clinical success of implants depends on rapid osseointegration, and new materials are being developed considering the increasing demand. Considering cobalt (Co) antibacterial characteristics, we developed Co-deposited titanium (Ti) using direct current (DC) sputtering and investigated it as a new material for implant dentistry. The material was characterized using atomic absorption spectroscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The material's surface topography, roughness, surface wettability, and hardness were also analyzed. The Co thin film (Ti-Co15) showed excellent antibacterial effects against microbes implicated in peri-implantitis. Furthermore, Ti-Co15 was compatible and favored the attachment and spreading of MG-63 cells. The alkaline phosphatase and calcium mineralization activities of MG-63 cells cultured on Ti-Co15 remained unaltered compared to Ti. These data correlated well with the time-dependent expression of ALP, RUNX-2, and BMP-2 genes involved in osteogenesis. The results demonstrate that Co-deposited Ti could be a promising material in implant dentistry.

In-Vitro Evaluation of Photofunctionalized Implant Surfaces in a High-Glucose Microenvironment Simulating Diabetics.

The present study aimed to assess the efficacy of photofunctionalization on commercially available dental implant surfaces in a high-glucose environment. Discs of three commercially available implant surfaces were selected with various nano- and microstructural alterations (Group 1-laser-etched implant surface, Group 2-titanium-zirconium alloy surface, Group 3-air-abraded, large grit, acid-etched surface). They were subjected to photo-functionalization through UV irradiation for 60 and 90 min. X-ray photoelectron spectroscopy (XPS) was used to analyze the implant surface chemical composition before and after photo-functionalization. The growth and bioactivity of MG63 osteoblasts in the presence of photofunctionalized discs was assessed in cell culture medium containing elevated glucose concentration. The normal osteoblast morphology and spreading behavior were assessed under fluorescence and phase-contrast microscope. MTT (3-(4,5 Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and alizarin red assay were performed to assess the osteoblastic cell viability and mineralization efficiency. Following photofunctionalization, all three implant groups exhibited a reduced carbon content, conversion of Ti4+ to Ti3+, increased osteoblastic adhesion, viability, and increased mineralization. The best osteoblastic adhesion in the medium with increased glucose was seen in Group 3. Photofunctionalization altered the implant surface chemistry by reducing the surface carbon content, probably rendering the surfaces more hydrophilic and conducive for osteoblastic adherence and subsequent mineralization in high-glucose environment.

An Indigenous, Field-Deployable, Lateral Flow Immunochromatographic Assay Rapidly Detects Infectious Myonecrosis in Shrimp, Litopenaeus vannamei.

Shrimp farming is an important socioeconomic activity worldwide. Infectious myonecrosis virus (IMNV) is an important shrimp virus responsible for significant mortality (up to 70%) in Litopenaeus vannamei. We produced recombinant capsid protein (r-IMNV31) and obtained a highly specific antibody, anti-r-IMNV31, which was used in WOAH-approved ELISA and Western blot to detect IMNV. Further, anti-r-IMNV31 was employed in an indigenously developed lateral flow immunoassay (LFA) with gold nanoparticles as a visual label. Using LFA, IMNV could be detected rapidly (20 min) from tissue homogenate with high specificity, reproducibility, and sensitivity (LOD = 103 viral particles). LFA was validated with "gold standard" qRT-PCR using 60 samples with high sensitivity (100%), specificity (86%). A Cohen's kappa coefficient of 0.86 suggested "good agreement" between LFA and qRT-PCR. With a shelf-life of ~ 1 year at ambient temperature, the use of LFA in the on-site detection of IMNV by shrimp farmers will be a reality.

A concise review on implications of silver nanoparticles in bone tissue engineering.

Skeletal disorders represent a variety of degenerative diseases that affect bone and cartilage homeostasis. The regenerative capacity of bone is affected in osteoporosis, osteoarthritis, rheumatoid arthritis, bone fractures, congenital defects, and bone cancers. There is no viable, non-invasive treatment option and bone regeneration requires surgical intervention with the implantation of bone grafts. Incorporating nanoparticles in bone grafts have improved fracture healing by providing fine structures for bone tissue engineering. It is currently a revolutionary finding in the field of regenerative medicine. Silver nanoparticles (AgNPs) have garnered particular attention due to their well-known anti-microbial and potential osteoinductive properties. In addition, AgNPs have been demonstrated to regulate the proliferation and differentiation of mesenchymal stem cells (MSCs) involved in bone regeneration. Furthermore, AgNPs have shown toxicity towards cancer cells derived from bone. In the last decade, there have been multiple studies focusing on the effect of nanoparticles on the proliferation and/or differentiation of MSCs and bone cancer cells; however, the specific studies with AgNPs are limited. Although the reported investigations show promising in vitro and in vivo potential of AgNPs for application in bone regeneration, more studies are required to ensure their implications in bone tissue engineering. This review aims to highlight the current advances related to the production of AgNPs and their effect on MSCs and bone cancer cells, which will potentiate their possible implications in orthopedics. Moreover, this review article evaluates the future of AgNPs in bone tissue engineering.

Development and characterization of five novel cell lines from snubnose pompano, Trachinotus blochii (Lacepede, 1801), and their application in gene expression and virological studies.

Five novel permanent cell lines have been established from gill, heart, kidney, eye and fin of snubnose pompano, Trachinotus blochii. They were designated as snubnose pompano gill (SPG), snubnose pompano heart (SPH), snubnose pompano kidney (SPK), snubnose pompano eye (SPE) and snubnose pompano fin (SPF), respectively. All these cell lines were characterized and cryopreserved successfully at different passage levels. Cell lines were passaged every alternate day; SPG, SPH, SPK, SPE and SPF cell lines attained passage levels of 68, 74, 82, 79 and 106, respectively, since the initiation of their development in 2019. The cell lines grew well in Leibovitz's 15 medium containing 15% foetal bovine serum at 28°C. Immunophenotyping of the cell lines revealed the presence of fibronectin and pancytokeratin. No mycoplasma contamination was found. The transfection study revealed the gene expression efficiency of these cell lines by expressing the green fluorescent protein (GFP). The authentication on origin of cell lines from T. blochii was confirmed by amplification of species-specific mitochondrial cytochrome oxidase I gene. The results showed the susceptibility of these cell lines to fish nodavirus (FNV) and tilapia lake virus (TiLV) and resistance to cyprinid herpesvirus 2 (CyHV-2). The FNV infection in the cell lines was confirmed by RT-PCR, Western blot, ELISA and immunocytochemistry, while TiLV infection was confirmed by RT-PCR assay. These results revealed that these cell lines are suitable for virological and foreign gene expression studies.

Nanomaterials: new weapons in a crusade against phytopathogens.

Bacteria, fungi, viruses, and nematodes are the major causal agents of plant diseases. These phytopathogens are responsible for about 10-40% losses in productivity and quality of food crops and horticultural produce. Although eradication of pathogens is not possible, control of plant diseases has been an area of continuous improvement/research. Use of antimicrobials, bacteriophages, and biocontrol agents, natural and synthetic agrochemicals along with best farm management practices constitute integrated measures for disease control. However, the quest for new materials continues due to pesticide resistance in the pathogens, emergence of new serotypes, and accumulation of high quantities of agrochemical contaminants in the ecosystem and associated environmental hazards, specificity of biocontrol agents, succession of pathogens during the plant growth phase, etc. The emergence of "nanotechnology," a multidisciplinary field of research, has provided a plethora of nanomaterials for potential applications in the agricultural sector. Control of plant diseases requires agents that reduce the pathogen to manageable levels, tools for early-stage detection of pathogen, and compounds that elicit immune response in the host plants. Nanomaterials have in fact been assessed for their utility in all these approaches for disease control. The present review discusses nanomaterials for controlling phytopathogens, nanomaterials in plant disease diagnostics, and nanomaterials as elicitors of the plant immune system. These nanomaterials thus represent new weapons in the fight against the phytopathogens. Recent studies indicate that nanomaterials will be a crucial component in the agroecosystem.

Gene expression is influenced due to 'nano' and 'ionic' copper in pre-formed Pseudomonas aeruginosa biofilms.

Today, researchers across the globe suggest the use of antimicrobial coatings containing copper nanoparticles (CuNPs) complementing the traditional protocols to prevent hospital-acquired infections (HAIs). Since Pseudomonas aeruginosa is one of the commonest opportunistic pathogens, we assessed the anti-biofilm activity of CuNPs in P. aeruginosa MTCC 3541 and compared it with Cu2+ (copper sulphate) since the latter continues to be used as an antimicrobial-of-choice in food industries, agriculture and water treatment. In this study, we synthesized and characterized stable poly-acrylic acid (PAA) coated CuNPs with a size of 66-150 nm and zeta potential -13 mV. Pseudomonas aeruginosa MTCC 3541 biofilms were highly resistant to both CuNPs and Cu2+ (minimum biofilm inhibitory concentration, MBIC 300 and >600 µg/mL respectively). Scanning electron microscopy revealed alterations in cell morphology upon treatment with CuNPs. A closer analysis of the biofilm-specific gene expression (qRT-PCR) revealed that CuNPs downregulated the genes involved in biofilm matrix formation, motility, efflux, membrane lipoprotein synthesis and DNA replication. Both, CuNPs and Cu2+ up regulated copper resistance and biofilm dispersion genes. Copper did not affect the bacterial communication system as evidenced by downregulation of the negative regulator of quorum sensing. The gene expression analysis reveals multiple cellular targets for CuNPs and ionic Cu. The present study highlights the fact that CuNPs affect the membrane functions adversely damaging the cell surface. In pre-formed biofilms, CuNPs were more toxic and displayed distinct responses attributable due to 'nano' and 'ionic' copper. Our findings thus support the use of CuNPs for curbing HAIs.

Nanomaterials for the control of bacterial blight disease in pomegranate: quo vadis?

Bacterial blight, caused by Xanthomonas axonopodis pv. punicae, Xap is a serious threat to commercially successful pomegranate (Punica granatum L) crop. Owing to the non-availability of disease-resistant varieties of pomegranate, integrated disease management involving change of season, adequate nutrition, and preventive sprays of bactericides is used to control Xap. We undertook a systematic study to assess the efficacy of metal-based nanomaterials (Cu, CuO, ZnO, CaO, MgO) for the control of Xap. The antimicrobial effectiveness was in the order Cu > ZnO > MgO > CuO with MIC (minimum inhibitory concentration) 2.5, 20, 190, 200, and 1600 µg/ml. A time-to-kill curve indicated that Cu nanoparticles (CuNPs) killed Xap cells within 30 min at 2.5 µg/ml. Under controlled conditions (polyhouse), foliar application of CuNPs (400 µg/ml) resulted in ~ 90 and ~ 15% disease reduction in 6-month-old infected plants at early (disease severity 10%) and established (disease severity 40%) stages of infection, respectively. In a subsequent field study on severely infected 7-year-old plants, applications of nanoparticles reduced the disease incidence by ~ 20% as compared to untreated control. Microscopic observations revealed that CuNPs reduced the bacterial colonization of the leaf surface. Anti-Xap activity of foliar applied CuNPs was on par with conventionally used copper oxychloride (3000 µg/ml) albeit at 8-fold reduced copper concentration. Thus, early disease detection and application of effective dosage of copper nanoparticles can indeed help the farmer in achieving rapid infection control. Further studies on use of combinations of nanoparticles for management of bacterial blight are warranted.

Antioxidant-antibacterial containing bi-layer scaffolds as potential candidates for management of oxidative stress and infections in wound healing.

Tissue engineering techniques are continuously evolving towards providing better microenvironment along with therapeutic potential to address the skin tissue defects. Factors such as microbial infections, presence of excessive free radicals and depletion in antioxidant based scavenging systems pose serious challenges by prolonging inflammation and delaying the repair process. Incorporation of bioactive molecules in polymer based biomimetic scaffolds may present new vistas for handling chronic wounds. In this study, chitosan/collagen scaffolds incorporating 0.5, 1 and 2% (w/w) silymarin (CS-CO-SM) were synthesized and studied for their biocompatibility, in vitro release kinetics and anti-oxidant activity. The release kinetics of silymarin from the CS-CO-SM scaffold showed an initial burst followed by sustained release. The scaffolds were biocompatible and supported the recovery of COS-7 cells from UV induced oxidative stress. Further the CS-CO-SM(2) scaffolds were used to fabricate a bi-layer scaffold by layer upon layer arrangement with CS-Ag3 (3% Ag, w/w). The Ag was incorporated to impart antimicrobial property to the scaffold. The in vivo studies on bi-layer scaffolds were carried out in Wistar rat models at 3, 7 and 10 days post injury and the skin excisions were studied for wound contraction, histology (H&E staining), and lipid peroxidation. The bi-layer scaffold accelerated the process of wound healing with no inflammatory cells, proliferation of fibroblast, neovascularization and collagen deposition. By day 10 post transplantation of the scaffold, the skin had a structure similar to normal skin with complete re-epithelization. This bi-layer scaffold with antioxidant and antimicrobial properties promotes wound healing and is proposed as a potential tissue engineering material for managing chronic wounds.

Transcriptome analysis of silver nanoparticles treated Staphylococcus aureus reveals potential targets for biofilm inhibition.

The biofilms of Staphylococcus aureus on the implanted materials and chronic wounds are life-threatening and are a substantial financial burden on the healthcare system. Silver nanoparticles (SNP), known for their multi-level physiological effects in planktonic cells could be a promising agent in the treatment of biofilm-related infections also. To gain insight into the effects of SNP on various physiological processes in biofilms we studied the transcriptome of Staphylococcus aureus ATCC 29213. To distinguish between 'nanoparticles-specific' and 'ion-specific' effect of silver, we performed a comparative analysis of the functional genes in response to Ag+. As compared to untreated biofilms, 21% (i.e. 629 genes) and 28.5% (i. e. 830 genes) of the total functional coding genes were differentially regulated upon exposure to SNP and Ag+. Genes encoding capsular polysaccharides, intercellular adhesion, virulence were downregulated in SNP and Ag+ treated biofilms. Genes involved in carbohydrate, protein metabolism including DNA and RNA synthesis, oxidative stress etc. were differentially expressed. Further, activation of efflux pumps and multidrug export proteins was observed, which clearly indicates the presence of metal stress resistance determinants in S. aureus. Silver blocked the integration of mobile genetic elements in S. aureus genome. Our study points out quorum sensing and virulence determinants as possible targets for inhibition of biofilms possibly with/without existing antibiotics. However, further studies on these aspects are warranted. Scanning electron microscopy (SEM) and confocal microscopy revealed changes in biofilm morphology, architecture and thickness in presence of silver nanoparticles and ionic silver, substantiating the transcriptome data.

Zinc use efficiency is enhanced in wheat through nanofertilization.

Ferti-fortification of wheat with zinc, an essential micronutrient is one of the strategies for combating 'hidden hunger' in a large proportion of people all over the world. During fertilization, application of large quantities of micronutrients often results in nutrient wastage and subsequent environmental pollution. Here, we report zinc complexed chitosan nanoparticles (Zn-CNP) for ferti-fortification of durum wheat in field-scale experiments. The efficacy of Zn-CNP was assessed vis-à-vis conventionally applied ZnSO4 (0.2%; 400 mgL-1 zinc) in two durum wheat genotypes (MACS 3125, an indigenous high yielding genotype and UC 1114, a genotype containing the Gpc-B1gene). The observed grain zinc enrichment using Zn-CNP nanocarrier (~36%) and conventional ZnSO4 (~50%) were comparable, despite 10 folds less zinc (40 mgL-1) used in the former. Nanofertilizer application increased grain zinc content without affecting grain yield, protein content, spikelets per spike, thousand kernel weight, etc. Grain zinc enrichment observed in the four-year field trials on plots with varying soil zinc content was consistent, proving the utility of Zn-CNP as a novel nanofertilizer which enhanced fertilizer use efficiency. Our work describes a new paradigm in micronutrient fortification, viz. 'use nanofertilizers at the right place, right time and in right doses'.

Nanocarrier-mediated foliar zinc fertilization influences expression of metal homeostasis related genes in flag leaves and enhances gluten content in durum wheat.

BACKGROUND: Wheat is the staple food for most of the world's population; however, it is a poor source of zinc. Foliar fertilization of zinc via zinc loaded chitosan nanocarriers (Zn-CNP) post-anthesis has proved to be a promising approach for grain zinc enhancement in durum wheat as evidenced in our earlier study. However, the molecular mechanism of uptake of zinc via Zn-CNP remains unclear. METHODS/PRINCIPLE FINDINGS: Foliar application of Zn-CNP was performed at post anthesis stages in two durum wheat cultivars (MACS 3125 and UC1114, containing the Gpc-B1 gene), and expression levels of several metal-related genes were analyzed during early senescence. Zn-CNP application indeed caused changes in gene expression as revealed by qPCR data on representative genes involved in metal homeostasis, phloem transporters, and leaf senescence. Furthermore, zinc-regulated transporters and iron (Fe)-regulated transporter-like protein (ZIP) family [ZIP1, ZIP7, ZIP15], CA (carbonic anhydrase), and DMAS (2'-deoxymugineic acid synthase) in flag leaves exhibited significant correlation with zinc content in the seeds. The analysis of grain endosperm proteins showed enhancement of gamma gliadins while other gluten subunits decreased. Gene expression within ZIP family members varied with the type of cultivar mostly attributed to the Gpc-B1, concentration of external zinc ions as well as the type of tissue analyzed. Correlation analysis revealed the involvement of the selected genes in zinc enhancement. CONCLUSION: At the molecular level, uptake of zinc via Zn-CNP nanocarrier was comparable to the uptake of zinc via common zinc fertilizers i.e. ZnSO4.

In vitro and in vivo studies of a novel bacterial cellulose-based acellular bilayer nanocomposite scaffold for the repair of osteochondral defects.

Bacterial cellulose (BC) is a naturally occurring nanofibrous biomaterial which exhibits unique physical properties and is amenable to chemical modifications. To explore whether this versatile material can be used in the treatment of osteochondral defects (OCD), we developed and characterized novel BC-based nanocomposite scaffolds, for example, BC-hydroxyapatite (BC-HA) and BC-glycosaminoglycans (BC-GAG) that mimic bone and cartilage, respectively. In vitro biocompatibility of BC-HA and BC-GAG scaffolds was established using osteosarcoma cells, human articular chondrocytes, and human adipose-derived mesenchymal stem cells. On subcutaneous implantation, the scaffolds allowed tissue ingrowth and induced no adverse immunological reactions suggesting excellent in vivo biocompatibility. Implantation of acellular bilayered scaffolds in OCD created in rat knees induced progressive regeneration of cartilage tissue, deposition of extracellular matrix, and regeneration of subchondral bone by the host cells. The results of micro-CT revealed that bone mineral density and ratio of bone volume to tissue volume were significantly higher in animals receiving bilayered scaffold as compared to the control animals. To the best of our knowledge, this study proves for the first time, the functional performance of acellular BC-based bilayered scaffolds. Thus, this strategy has great potential for clinical translation and can be used in repair of OCD.

Nanoscale silver depositions inhibit microbial colonization and improve biocompatibility of titanium abutments.

Although titanium dental implants are biocompatible, exhibit excellent corrosion resistance and high mechanical resistance, the material fails in providing resistance to infection because it exhibits poor antimicrobial activity. To address these issues, we deposited silver onto titanium abutments (Grade 5 titanium discs) using direct current (DC) sputtering and assessed the antimicrobial activity and biocompatibility of the modified implant material. Atomic absorption spectrometry and X-ray photoelectron spectroscopy were employed to investigate the concentration and elemental composition of the deposited silver. As expected, silver deposited using DC plasma was uniform and good control over the deposition could be achieved by varying the sputtering time. Moderate biocompatible responses (up to 69% viability) were observed in primary human gingival fibroblast cells incubated in the presence of Ti sputtered with Ag for 5min. Silver deposited titanium (Ti-Ag) showed excellent antibacterial effects on Pseudomonas aeruginosa and Streptococcus mutans at a very low concentration (Ag content 1.2 and 2.1µg/mm2). However, higher concentration of silver (6µg/mm2) was required to achieve a reduction in cell viability of Staphylococcus aureus and Candida albicans. The silver sputtered Ti abutments could maintain a long-term antibacterial activity as evidenced by the release of silver up to 22days in simulated body fluid. Our study illustrates that silver deposited titanium is indeed a promising candidate for soft tissue integration on dental abutments and prevents initial microbial adhesion.

Zinc complexed chitosan/TPP nanoparticles: A promising micronutrient nanocarrier suited for foliar application.

Cultivation of cereals in zinc deficient soils leads to declined nutritional quality of grain. Zinc deficiency in humans is a consequence of consumption of micronutrient deficient cereals as staple food. To achieve an increase in zinc density in grain, we evaluated zinc complexed chitosan nanoparticles (Zn-CNP) as a potential 'nanocarrier' suited for foliar fertilization. Zn-CNP were synthesized using tri-polyphosphate as a cross-linker. Spherical Zn-CNP (diameter 250-300nm) were positively charged (zeta potential, +42.34mV) and contained ∼20mg Zn/g (w/w). Plant growth in zinc deficient sand media, followed by foliar application of Zn-CNP (twice-a-week, for 5 weeks) after anthesis resulted in 27 and 42% increase in grain zinc content of MACS 3125 and UC1114 (durum wheat cultivars) respectively. Translocation of zinc ions from foliar applied Zn-CNP into the leaf and seed tissue was demonstrated using zinquin and dithizone stains, respectively. The study indicates the suitability of chitosan-based nanocarriers in agronomic biofortification.

Lateral flow assay for rapid detection of white spot syndrome virus (WSSV) using a phage-displayed peptide as bio-recognition probe.

White spot disease caused by the white spot syndrome virus (WSSV) has a major socio-economic impact on shrimp farming in India. It has been realized that a field-usable diagnostic capable of rapid detection of WSSV can prevent huge economic losses in disease outbreaks. In this work, we explored the possibility of using a peptide as bio-recognition probe in a field-usable device for the detection of WSSV from infected shrimps and prawns. A commercially available random phage-display library was screened against rVP28 (a major structural protein of WSSV, expressed as a recombinant protein in Escherichia coli). A bacteriophage clone VP28-4L was obtained, and its binding to purified rVP28 protein as well as WSSV from infected shrimp Litopaeneus vannamei tissue was confirmed by ELISA and western blot. The apparent equilibrium dissociation constant (Kd,app) was calculated to be 810 nM. VP28-4L did not show cross-reactivity with any other shrimp viruses. A 12-mer peptide (pep28, with the sequence 'TFQAFDLSPFPS') displayed on the VP28-4L was synthesized, and its diagnostic potential was evaluated in a lateral flow assay (LFA). Visual detection of WSSV could be achieved using biotinylated-pep28 and streptavidin-conjugated gold nanoparticles. In LFA, 12.5 µg/mL of the virus could be detected from L. vannamei gill tissue homogenate within 20 min. Pep28 thus becomes an attractive candidate in bio-recognition of WSSV in field-usable diagnostic platforms benefitting the aquaculture sector.

Field-Usable Lateral Flow Immunoassay for the Rapid Detection of White Spot Syndrome Virus (WSSV).

BACKGROUND: White spot disease (WSD), a major threat to sustainable aquaculture worldwide, is caused by White spot syndrome virus (WSSV). The diagnosis of WSD relies heavily on molecular detection of the virus by one-step PCR. These procedures are neither field-usable nor rapid enough considering the speed at which the virus spreads. Thus, development of a rapid, reliable and field-usable diagnostic method for the detection of WSSV infection is imperative to prevent huge economic losses. METHODS/PRINCIPAL FINDINGS: Here, we report on the development of a lateral flow immunoassay (LFIA) employing gold nanoparticles conjugated to a polyclonal antibody against VP28 (envelope protein of WSSV). The LFIA detected WSSV in ~20 min and showed no cross-reactivity with other shrimp viruses, viz. Monodon Baculovirus (MBV), Hepatopancreatic parvovirus (HPV) and Infectious Hypodermal and Hematopoietic Necrosis virus (IHHNV). The limit of detection (LOD) of the assay, as determined by real-time PCR, was 103 copies of WSSV. In a time course infectivity experiment, ~104 WSSV particles were injected in Litopenaeus vannamei. The LFIA could rapidly (~ 20 min) detect the virus in different tissues after 3 h (hemolymph), 6 h (gill tissue) and 12 h (head soft tissue, eye stalk, and pleopod) of infection. Based on these findings, a validation study was performed using 75 field samples collected from different geographical locations in India. The LFIA results obtained were compared with the conventional "gold standard test", viz. one-step PCR. The analysis of results in 2x2 matrix indicated very high sensitivity (100%) and specificity (96.77%) of LFIA. Similarly, Cohen's kappa coefficient of 0.983 suggested "very good agreement" between the developed LFIA and the conventional one-step PCR. CONCLUSION: The LFIA developed for the rapid detection of WSSV has an excellent potential for use in the field and could prove to be a boon to the aquaculture industry.

Fruit peels support higher yield and superior quality bacterial cellulose production.

Fruit peels, also known as rinds or skins, are wastes readily available in large quantities. Here, we have used pineapple (PA) and watermelon (WM) peels as substrates in the culture media (containing 5 % sucrose and 0.7 % ammonium sulfate) for production of bacterial cellulose (BC). The bacterial culture used in the study, Komagataeibacter hansenii produced BC under static conditions as a pellicle at the air-liquid interface in standard Hestrin and Schramm (HS) medium. The yield obtained was ~3.0 g/100 ml (on a wet weight basis). The cellulosic nature of the pellicle was confirmed by CO2, H2O, N2, and SO2 (CHNS) analysis and Fourier transform infrared (FT-IR) spectroscopy. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) of the pellicle revealed the presence of flat twisted ribbonlike fibrils (70-130 nm wide). X-ray diffraction analysis proved its crystalline nature (matching cellulose I) with a crystallinity index of 67 %. When K. hansenii was grown in PA and WM media, BC yields were threefolds or fourfolds higher than those obtained in HS medium. Interestingly, textural characterization tests (viz., SEM, crystallinity index, resilience, hardness, adhesiveness, cohesiveness, springiness, shear energy and stress, and energy required for puncturing the pellicle) proved that the quality of BC produced in PA and WM media was superior to the BC produced in HS medium. These findings demonstrate the utility of the newly designed media for getting higher yields and better quality of BC, which could make fermentative production of BC more attractive on a commercial scale.