Circulating Phylotypes of White Spot Syndrome Virus in Bangladesh and Their Virulence

White Spot Syndrome Virus (WSSV) has emerged as one of the most prevalent and lethal viruses globally and infects both shrimps and crabs in the aquatic environment. This study aimed to investigate the occurrence of WSSV in different ghers of Bangladesh and the virulence of the circulating phylotypes. We collected 360 shrimp (Penaeus monodon) and 120 crab (Scylla sp.) samples from the south-east (Cox’s Bazar) and south-west (Satkhira) coastal regions of Bangladesh. The VP28 gene-specific PCR assays and sequencing revealed statistically significant (p < 0.05, Kruskal–Wallis test) differences in the prevalence of WSSV in shrimps and crabs between the study areas (Cox’s Bazar and Satkhira) and over the study periods (2017–2019). The mean Log load of WSSV varied from 8.40 (Cox’s Bazar) to 10.48 (Satkhira) per gram of tissue. The mean values for salinity, dissolved oxygen, temperature and pH were 14.71 ± 0.76 ppt, 3.7 ± 0.1 ppm, 34.11 ± 0.38 °C and 8.23 ± 0.38, respectively, in the WSSV-positive ghers. The VP28 gene-based phylogenetic analysis showed an amino-acid substitution (E→G) at the 167th position in the isolates from Cox’s Bazar (referred to as phylotype BD2) compared to the globally circulating one (BD1). Shrimp PL artificially challenged with BD1 and BD2 phylotypes with filtrates of tissue containing 0.423 × 109 copies of WSSV per mL resulted in a median LT50 value of 73 h and 75 h, respectively. The in vivo trial showed higher mean Log WSSV copies (6.47 ± 2.07 per mg tissue) in BD1-challenged shrimp PL compared to BD2 (4.75 ± 0.35 per mg tissue). Crabs infected with BD1 and BD2 showed 100% mortality within 48 h and 62 h of challenge, respectively, with mean Log WSSV copies of 12.06 ± 0.48 and 9.95 ± 0.37 per gram tissue, respectively. Moreover, shrimp antimicrobial peptides (AMPs), penaeidin and lysozyme expression were lower in the BD1-challenged group compared to BD2 challenged shrimps. These results collectively demonstrated that relative virulence properties of WSSV based on mortality rate, viral load and expression of host immune genes in artificially infected shrimp PL could be affected by single aa substitution in VP28.

Effect of topical fluoride gel and fluoride varnish in the prevention of white spot lesions in patients undergoing fixed orthodontic treatment: An in vivo study

Objectives: Our primary objective was to establish the efficacy of fluoride gel and fluoride varnish in the prevention of white spot lesions (WSLs) development during fixed orthodontic treatment. Materials and Methods: The study sample consisted of 60 adult patients in a prospective split-mouth study design. Interventions, that is, topical fluoride gel and topical fluoride varnish were assigned at the time of bonding to either the right or left halves of the dentition. In all subjects, repeated evaluation of demineralization was done on the facial surfaces of sample teeth in each quadrant. Evaluation using laser fluorescence and by direct visual observation under magnification was carried out at bonding (T0), 3 months (T1), and 6 months (T2). Results: The distribution of mean DIAGNOdent score at T1 (3.14 ± 1.00 vs. 2.81 ± 0.852) and T2 (4.17 ± 1.41 vs. 3.51 ± 1.13) was observed which is significantly higher in the Gel group compared to the Varnish group. In the Gel group, the distribution of mean DIAGNOdent score at T1 (3.14 ± 1.00) and T2 (4.17 ± 1.41) is significantly higher compared to mean DIAGNOdent score at baseline T0 (2.07 ± 0.66). In the Varnish group, the distribution of mean DIAGNOdent score at T1 (2.81 ± 0.852) and T2 (3.51 ± 1.13) is significantly higher compared to the mean DIAGNOdent score at T0 (2.07 ± 0.66). Visual scores also correlated with DIAGNOdent scores. Conclusion: Fluoride varnish is more efficacious than fluoride gel in reducing enamel demineralization. Initial application of fluoride varnish around the orthodontic bracket at bonding appointment can offer significant protection against WSLs.

Evaluation of white spot lesions around orthodontic brackets using different bonding agents – An in vivo study

Objectives: The objectives of the study were to assess the white spot lesions around orthodontic bracket macroscopically using two different bonding agents – one with amorphous calcium phosphate (ACP) (Aegis Ortho) and one without ACP (Transbond XT). Materials and Methods: The study comprises 10 patients from 14 to 23 years of age. Patients were divided into control and study groups. Forty premolar teeth were then observed (20 teeth in each group). Bonding procedure was done and brackets were positioned on all four 1st pre-molars teeth and pre-treatment photographs were taken. The experimental material used was Aegis Ortho composite (study group) and Transbond XT (control group). Debonding procedure (by Wing deformation technique) was performed after 16 weeks which led to adhesive fracture at composite resin adhesive bracket interface leaving essentially all adhesive on the enamel. Then, follow-up photographs were taken to evaluate each. Results: Aegis Ortho containing ACP used for bonding purpose, provided lesser enamel demineralization than Transbond XT. Conclusion: Aegis Ortho for orthodontic bonding is significantly more beneficial and reliable, however, further investigations are also required to understand its clinical performance better.

A new variety of Geranium ocellatum (Geraniaceae) from Uttarakhand, India

A new variety, Geranium ocellatum var. albiflorum, is described here from Tehri district of Uttarakhand state, India. The new variety is readily distinguished from G. ocellatum var. ocellatum by its central white spot at the petal base, dichasial inflorescence and peduncle length. A detailed description, photographs and conservation status are provided for the new variety. A key to the varieties of G. ocellatum is also provided.

Nanoparticles in inhibiting Pantoea ananatis and to control maize white spot

ABSTRACT: Maize white spot (MWS) caused by Pantoea ananatis is one main maize leaf diseases, and nanoparticles (NPs) are an innovative approach for bacterial disease control. This research evaluated the toxicity of pure NPs and doped NPs with different elements in inhibiting bacterial growth and to control MWS. Pure NPs and ZnO NPs doped with silver (Ag), gold (Au), copper (Cu), iron (Fe), manganese (Mn), and nickel (Ni) at different concentrations were used to determine the toxicity for P. ananatis in vitro, evaluating the bacterial growth inhibition zone. To assess the control of MWS, in the preventive application, maize plants were sprayed with NPs of ZnO:0.1Cu, ZnO:0.05Fe, ZnO:0.2Mn and ZnO:0.7Ni at 10, 5 or 2.5 mg mL-1, and after 3 days, the plants were inoculated with bacterial suspension. To assess the curative application, plants were inoculated with the bacteria, and 3 days later sprayed with the NPs. The disease severity was assessed and the area under the disease-progress curve (AUDPC) was calculated. The doped ZnO NPs with different elements, and at different concentrations inhibited bacterial growth in vitro. NPs of ZnO:0.1Cu and ZnO:0.2Mn at 5 or 2.5 mg mL-1, in both applications reduced the severity of MWS, showing potential for use in the disease management.