CRISPR/Cas9: A Tool to Circumscribe Cotton Leaf Curl Disease

The begomoviruses (family Geminiviridae) associated with cotton leaf curl disease (CLCuD) pose a major threat to cotton productivity in South-East Asia including Pakistan and India. These viruses have single-stranded, circular DNA genome, of ∼2800 nt in size, encapsidated in twinned icosa-hedera, transmitted by ubiquitous whitefly and are associated with satellite molecules referred to as alpha- and betasatellite. To circumvent the proliferation of these viruses numerous techniques, ranging from conventional breeding to molecular approaches have been applied. Such devised strategies worked perfectly well for a short time period and then viruses relapse due to various reasons including multiple infections, where related viruses synergistically interact with each other, virus proliferation and evolution. Another shortcoming is, until now, that all molecular biology approaches are devised to control only helper begomoviruses but not to control associated satellites. Despite the fact that satellites could add various functions to helper begomoviruses, they remain ignored. Such conditions necessitate a very comprehensive technique that can offer best controlling strategy not only against helper begomoviruses but also their associated DNA-satellites. In the current scenario clustered regulatory interspaced short palindromic repeats (CRISPR)/CRISPR associated nuclease 9 (Cas9) has proved to be versatile technique that has very recently been deployed successfully to control different geminiviruses. The CRISPR/Cas9 system has been proved to be a comprehensive technique to control different geminiviruses, however, like previously used techniques, only a single virus is targeted and hitherto it has not been deployed to control begomovirus complexes associated with DNA-satellites. Here in this article, we proposed an inimitable, unique, and broad spectrum controlling method based on multiplexed CRISPR/Cas9 system where a cassette of sgRNA is designed to target not only the whole CLCuD-associated begomovirus complex but also the associated satellite molecules.

Insight on stem cell preconditioning and instructive biomaterials to enhance cell adhesion, retention, and engraftment for tissue repair

Stem cells are a promising solution for the treatment of a variety of diseases. However, the limited survival and engraftment of transplanted cells due to a hostile ischemic environment is a bottleneck for effective utilization and commercialization. Within this environment, the majority of transplanted cells undergo apoptosis prior to participating in lineage differentiation and cellular integration. Therefore, in order to maximize the clinical utility of stem/progenitor cells, strategies must be employed to increase their adhesion, retention, and engraftment in vivo. Here, we reviewed key strategies that are being adopted to enhance the survival, retention, and engraftment of transplanted stem cells through the manipulation of both the stem cells and the surrounding environment. We describe how preconditioning of cells or cell manipulations strategies can enhance stem cell survival and engraftment after transplantation. We also discuss how biomaterials can enhance the function of stem cells for effective tissue regeneration. Biomaterials can incorporate or mimic extracellular function (ECM) function and enhance survival or differentiation of transplanted cells in vivo. Biomaterials can also promote angiogenesis, enhance engraftment and differentiation, and accelerate electromechanical integration of transplanted stem cells. Insight gained from this review may direct the development of future investigations and clinical trials.

Covalent immobilization of stem cell inducing/recruiting factor and heparin on cell-free small-diameter vascular graft for accelerated in situ tissue regeneration

The development of cell-free vascular grafts has tremendous potential for tissue engineering. However, thrombus formation, less-than-ideal cell infiltration, and a lack of growth potential limit the application of electrospun scaffolds for in situ tissue-engineered vasculature. To overcome these challenges, here we present development of an acellular tissue-engineered vessel based on electrospun poly(L-lactide-co-ɛ-caprolactone) scaffolds. Heparin was conjugated to suppress thrombogenic responses, and substance P (SP) was immobilized to recruit host cells. SP was released in a sustained manner from scaffolds and recruited human bone marrow-derived mesenchymal stem cells. The biocompatibility and biological performance of the grafts were evaluated by in vivo experiments involving subcutaneous scaffold implantation in Sprague-Dawley rats (n = 12) for up to 4 weeks. Histological analysis revealed a higher extent of accumulative host cell infiltration, neotissue formation, collagen deposition, and elastin deposition in scaffolds containing either SP or heparin/SP than in the control groups. We also observed the presence of a large number of laminin-positive blood vessels, von Willebrand factor (vWF(+) ) cells, and alpha smooth muscle actin-positive cells in the explants containing SP and heparin/SP. Additionally, SP and heparin/SP grafts showed the existence of CD90(+) and CD105(+) MSCs and induced a large number of M2 macrophages to infiltrate the graft wall compared with that observed with the control group. Our cell-free grafts could enhance vascular regeneration by endogenous cell recruitment and by mediating macrophage polarization into the M2 phenotype, suggesting that these constructs may be a promising cell-free graft candidate and are worthy of further in vivo evaluation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1352-1371, 2016.

Virus-Induced Gene Silencing in Cultivated Cotton (Gossypium spp.) Using Tobacco Rattle Virus

The study described here has optimized the conditions for virus-induced gene silencing (VIGS) in three cultivated cotton species (Gossypium hirsutum, G. arboreum, and G. herbaceum) using a Tobacco rattle virus (TRV) vector. The system was used to silence the homolog of the Arabidopsis thaliana chloroplastos alterados 1 (AtCLA1) gene, involved in chloroplast development, in G. herbaceum, G. arboreum, and six commercial G. hirsutum cultivars. All plants inoculated with the TRV vector to silence CLA1 developed a typical albino phenotype indicative of silencing this gene. Although silencing in G. herbaceum and G. arboreum was complete, silencing efficiency differed for each G. hirsutum cultivar. Reverse transcriptase polymerase chain reaction (PCR) and real-time quantitative PCR showed a reduction in mRNA levels of the CLA1 homolog in all three species, with the highest efficiency (lowest CLA1 mRNA levels) in G. arboreum followed by G. herbaceum and G. hirsutum. The results indicate that TRV is a useful vector for VIGS in Gossypium species. However, selection of host cultivar is important. With the genome sequences of several cotton species recently becoming publicly available, this system has the potential to provide a very powerful tool for the rapid, large-scale reverse-genetic analysis of genes in Gossypium spp.

In situ vascular regeneration using substance P-immobilised poly(L-lactide-co-ε-caprolactone) scaffolds: stem cell recruitment, angiogenesis, and tissue regeneration

In situ tissue regeneration holds great promise for regenerative medicine and tissue engineering applications. However, to achieve control over long-term and localised presence of biomolecules, certain barriers must be overcome. The aim of this study was to develop electrospun scaffolds for the fabrication of artificial vascular grafts that can be remodelled within a host by endogenous cell recruitment. We fabricated scaffolds by mixing appropriate proportions of linear poly (l-lactide-co-ε-caprolactone) (PLCL) and substance P (SP)-immobilised PLCL, using electrospinning to develop vascular grafts. Substance P was released in a sustained fashion from electrospun membranes for up to 30 d, as revealed by enzyme-linked immunosorbent assay. Immobilised SP remained bioactive and recruited human bone marrow-derived mesenchymal stem cells (hMSCs) in an in vitro Trans-well migration assay. The biocompatibility and biological performance of the scaffolds were evaluated by in vivo experiments involving subcutaneous scaffold implantations in Sprague-Dawley rats for up to 28 d followed by histological and immunohistochemical studies. Histological analysis revealed a greater extent of accumulative host cell infiltration and collagen deposition in scaffolds containing higher contents of SP than observed in the control group at both time points. We also observed the presence of a large number of laminin-positive blood vessels and Von Willebrand factor (vWF+) cells in the explants containing SP. Additionally, scaffolds containing SP showed the existence of CD90+ and CD105+ MSCs. Collectively, these findings suggest that the methodology presented here may have broad applications in regenerative medicine, and the novel scaffolding materials can be used for in situ tissue regeneration of soft tissues.

Neural networks for tracking of unknown SISO discrete-time nonlinear dynamic systems

This article presents a Lyapunov function based neural network tracking (LNT) strategy for single-input, single-output (SISO) discrete-time nonlinear dynamic systems. The proposed LNT architecture is composed of two feedforward neural networks operating as controller and estimator. A Lyapunov function based back propagation learning algorithm is used for online adjustment of the controller and estimator parameters. The controller and estimator error convergence and closed-loop system stability analysis is performed by Lyapunov stability theory. Moreover, two simulation examples and one real-time experiment are investigated as case studies. The achieved results successfully validate the controller performance.

Identification of risk factors for hepatitis B and C in Peshawar, Pakistan

Background

Hepatitis B and C need immediate worldwide attention as the infection rates are too high. More than 240 million people have chronic (long-term) liver infections. Every year, about 600,000 people die globally due to the acute or chronic consequences of hepatitis B and more than 350,000 people die from hepatitis C-related liver diseases.

Methods

Our study was designed as a case-control, descriptive study. It was conducted through formal interviews by using structured questionnaires. A total of 100 cases were included, with four controls for each case.

Results

This study confirms household contact, history of dental work, history of surgery, sexual contact, and history of transfusion (blood and its components) as the main risk factors which are responsible for the increased prevalence of hepatitis.

Conclusion

The important risk factors, responsible for the high prevalence of hepatitis B and C in our society are household contact, history of dental work, history of surgery, sexual contact, and history of transfusion (blood and its components). The odds ratio of probability for these risk factors are: 4.2 for household contact history, 4.1 for history of dental work, 3.9 for sexual contact, 2.7 for history of surgery, and 2.1 for history of transfusion. Associations of other predictor variables (diabetes status, education level, profession, contact sports, intravenous drug abuse, residence, immunosuppression, and skin tattoos) were not statistically significant.

Fabrication of tethered carbon nanotubes in cellulose acetate/polyethylene glycol-400 composite membranes for reverse osmosis

In this study pristine multi-walled carbon nanotubes (MWCNTs) were surface engineered (SE) in strong acidic medium by oxidation purification method to form SE-MWCNT. Five different amount of SE-MWCNT ranging from 0.1 to 0.5 wt% were thoroughly and uniformly dispersed in cellulose acetate/polyethylene glycol (CA/PEG400) polymer matrix during synthesis of membrane by dissolution casting method. The structural analysis, surface morphology and roughness was carried out by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM), respectively, which showed that the dispersed SE-MWCNT was substantially tethered in CA/PEG400 polymer matrix membrane. The thermogravimetric analysis (TGA) of membranes also suggested some improvement in thermal properties with the addition of SE-MWCNT. Finally, the performance of these membranes was assessed for suitability in drinking water treatment. The permeation flux and salt rejection were determined by using indigenously fabricated reverse osmosis pilot plant with 1000 ppm NaCl feed solution. The results showed that the tethered SE-MWCNT/CA/PEG400 polymer matrix membrane, with strong SE-MWCNTs/polymer matrix interaction, improved the salt rejection performance of the membrane with the salt rejection of 99.8% for the highest content of SE-MWCNT.

High-temperature electrical properties of silane cross-linked chitosan/poly(vinyl alcohol) membrane: thermal, mechanical and surface characterization

Chitosan and poly(vinyl alcohol) were blended and cross-linked with tetraethoxysilane and showed conductive properties. Impedance spectroscopy was used to study the influence of temperature on the electrical properties of the membranes. The conductivity of the membranes was increased with an increase in temperature. Free water was decreased and bound water was increased with an increase in cross-linker contents. The tensile strength improved, whereas elongation at break decreased by increasing the amount of cross-linker contents. The water contact angle of the membranes lowered with time, exhibiting the hydrophilic nature of the membranes. The novel characteristics of biocompatible membranes can be used in biomedical applications including biological schemes that require smaller charge in medicinal apparatus, bioelectrode coatings, etc.

Mechanical properties and variation in SOC going from La to Nd in intermetallic RIn3 and RSn3 (R = La, Ce, Pr, Nd)

The cubic rare-earth intermetallics RIn₃ and RSn₃ (R = La, Ce, Pr, Nd) have been investigated using the full potential linearized augmented plane waves plus local orbital method in the density functional theory framework.

Hypoglycaemic effects of methanolic extract of Canscora decussata (Schult) whole-plant in normal and alloxan-induced diabetic rabbits

In present study hypoglycaemic effects of the crude powdered C. decussata and its methanolic extract (ME) in alloxan diabetic rabbits were evaluated. The hypoglycaemic effect was measured by blood glucose, insulin level, HbA1c and his to pathology of pancreas. Glucose lowering effect of the ME was studied in diabetic rabbits. The effects of extract on blood glucose, body weight, food in take, fluid intake, OGTT were also evaluated. The results showed that 0.5,1 and 2g/kg of the powder significantly decreased blood glucose levels in normal rabbits and diabetic rabbits at the intervals checked. Oral intake of pioglitazone also reduced the levels in these rabbits. Synergistic hypoglycaemic effect of 600mg/kg of ME with different doses of insulin (2 & 3unit/kg, s/c) further reduced blood glucose levels of treated alloxan-diabetic rabbits. The oral glucose tolerance test revealed lowered area under curve values in ME treated rabbits. Treatment with ME (400 and 600 mg/kg) for 30 days showed highly significant decrease in blood glucose level by augmenting insulin secretion, HbA1cand significant increase in body weight, serum insulin levels in treated diabetic rabbits. Histopathology study showed regeneration of β-cells. These studies have, therefore, supported the traditional use of this herb in diabetic patients.

Prevalence of plasmid-mediated AmpC β-lactamases in Escherichia coli and Klebsiella pneumonia at tertiary care hospital of Islamabad, Pakistan

Enterobacteriaceae produces AmpC β-lactamases that make them resistant to commonly used antibiotics. AmpC β-lactamases can be chromosomal-mediated or plasmid-mediated AmpC β-lactamases (PABLs). The present study was undertaken to determine the occurrence of PABLs production in clinical isolates in Escherichia coli and Klebsiella pneumoniae. Among 1328 culture positive samples, 511 isolates were identified as E. coli (81.02%, n = 414) and K. pneumonia (18.98%, n = 97). Cefoxitin resistance was observed in E. coli (19.57%, n = 81) and K. pneumoniae (22.68%, n = 22). Out of these cefoxitin resistant isolates, 40.74% (n = 33) E. coli and 54.55% (n = 12) K. pneumoniae came out to be PABL producers. Prevalence of both PABLs and ESBLs in E. coli and K. pneumoniae was 29.24% (n = 8) and 47% (n = 5), respectively. Isolates coproducing PABLs and ESBL exhibited increased minimum inhibitory concentrations (MICs) for selected cephalosporins. This study documented a high frequency of PABLs producing isolates from hospital which may lead to serious therapeutic problem.

A distinct strain of chickpea chlorotic dwarf virus (genus Mastrevirus, family Geminiviridae) identified in cotton plants affected by leaf curl disease

As part of a study to determine the diversity of whitefly-transmitted viruses (genus Begomovirus, family Geminiviridae) associated with cotton leaf curl disease in Pakistan, leaf samples from cotton plants showing typical leaf curl disease symptoms were collected in various locations of Punjab province. Sequence analysis of full-length virus clones (~2.7 kb) showed plants to be infected with the begomovirus cotton leaf curl Burewala virus, the only virus identified in cotton in the Punjab since 2001. Surprisingly, a second virus, the leafhopper-transmitted chickpea chlorotic dwarf virus (CpCDV) of the genus Mastrevirus (family Geminiviridae), was identified in a small number of plants. The sequences of four CpCDV isolates from cotton originating from geographically distinct areas in Punjab were obtained. Analysis of the sequences showed them to represent a distinct, newly identified strain of CpCDV with the highest levels of nucleotide sequence identity to isolates of CpCDV strains C and D that have been identified previously in Pakistan. CpCDV has not been identified previously in cotton. The significance of this finding is discussed.

3-Chloro-4-[2-(4-chlorobenzylidene)hydrazinylidene]-1-methyl-3,4-dihydro-1H-2λ6,1-benzothiazine-2,2-dione

In the title compound, C₁₆H₁₃Cl₂N₃O₂S, the dihedral angle between the aromatic rings is 6.62 (2)° and the C=N—N=C torsion angle is 176.2 (4)°. The thia­zine ring shows an envelope conformation, with the S atom displaced by 0.633 (6) Å from the mean plane of the other five atoms (r.m.s. deviation = 0.037 Å). The Cl atom is an an axial conformation and is displaced by 2.015 (6) Å from the thia­zine ring plane. In the crystal, mol­ecules are linked by C—H⋯O inter­actions, generating a three-dimensional network. Very weak aromatic π–π stacking inter­actions [centroid–centroid separations = 3.928 (2) Å] are also observed.