Imidacloprid degrading efficiency of Pseudomonas plecoglossicida MBSB-12 isolated from pesticide contaminated tea garden soil of Assam

Long-term use of toxic pesticides in agricultural grounds has led to adverse effects on the environment and human health. Microbe-mediated biodegradation of pollutants is considered an effective strategy for the removal of contaminants in agricultural and environmental sustainability. Imidacloprid, a neonicotinoid class of pesticides, was widely applied insecticide in the control of pests in agricultural fields including the tea gardens of Assam. Here, native bacteria from imidacloprid contaminating tea garden soils were isolated and screened for imidacloprid degradation efficiency under laboratory conditions. Out of the 30 bacterial isolates, 4 were found to tolerate high concentrations of imidacloprid (25,000 ppm), one of which isolate MBSB-12 showed the highest efficiency for imidacloprid tolerance and utilization as the sole carbon source. Morphological, biochemical, and 16 S ribosomal RNA gene sequencing-based characterization revealed the isolate as Pseudomonas plecoglossicida MBSB-12. The isolate reduced 87% of extractable imidacloprid from the treated soil in 90 days compared to the control soil (without bacterial treatment). High-Resolution Mass Spectrometry (HRMS) analysis indicated imidacloprid breakdown to comparatively less harmful products viz., imidacloprid guanidine olefin [m/z = 209.0510 (M + H)⁺], imidacloprid urea [m/z = 212.0502 (M + H)⁺] and a dechlorinated degraded product of imidacloprid with m/z value 175.0900 (M + H)⁺. Further investigation on the molecular machinery of P. plecoglossicida MBSB-12 involved in the degradation of imidacloprid is expected to provide a better understanding of the degradation pathway.

Agricultural Land Use Influences Bacteriophage Community Diversity, Richness, and Heterogeneity

The last two decades have witnessed a large-scale conversion of crop cultivation areas into small and mid-sized tea plantations in Assam, India. Agricultural land-use pattern positively or negatively influences native hydrology and above- and belowground biodiversity. Very little is known about the effect of agricultural land-use patterns on the soil virus (especially, bacteriophage) community structure and function. This metagenomic-based study evaluated the rhizosphere viral community structure of three interlinked cultivation areas, viz., mixed cropping area (coded as CP1), tea-seed orchard (CP2), and monocropping tea cultivation (CP3). The bacteriophages belonged to four major classes with the dominance of Malgrandaviricetes (CP1: 79.37%; CP2: 64.62%; CP3: 4.85%) followed by Caudoviricetes (CP1: 20.49%; CP2: 35.22%; CP3: 90.29%), Faserviricetes (CP1: 0.03%; CP2: 0.08%; CP3: 3.88%), and Tectiliviricetes (CP1: 0.12%; CP2: 0.07%; CP3: 0.97%). Microviruses dominated the phage population in both CP1 and CP2, representing 79.35% and 64.59% of total bacteriophage abundance. Both CP1 and CP2 had higher bacteriophage richness (species richness, R in CP1: 65; R in CP2: 66) and lower evenness (Pielou's evenness index, J in CP1: 0.531; J in CP2: 0.579) compared to the CP3 (R: 30; J: 0.902). Principal component analysis of edaphic soil factors and bacteriophage community structure showed a reverse-proportional correlation between the levels of Al saturation, and exchangeable Al³⁺ ions with that of soil pH, and bacteriophage abundance. Our study indicates that monocropping tea cultivation soil bears less viral richness, abundance, and heterogeneity.

Epidemiological study of ocular trauma in an urban slum population in Delhi, India

Purpose:

To study the epidemiology and clinical profile of victims of ocular trauma in an urban slum population.

Materials and Methods:

This cross-sectional study, conducted on 500 families each in three randomly selected urban slums in Delhi, collected demographic data for all members of these families, and clinical data for all those who suffered ocular trauma at any time, that required medical attention. Data was managed on SPSS 11.0.

Results:

Of 6704 participants interviewed, 163 episodes of ocular trauma were reported by 158 participants (prevalence = 2.4%, confidence interval = 2.0 to 2.7) Mean age at trauma was 24.2 years. The association between the age of participants and the history of ocular trauma was significant (P < 0.001), when adjusted for sex, education and occupation. Males were significantly more affected. Blunt trauma was the commonest mode of injury (41.7%). Blindness resulted in 11.4% of injured eyes ( P = 0.028). Of 6704 participants, 1567 (23.4%) were illiterate, and no association was seen between education status and trauma, when adjusted for sex and age at injury. A significant association was noted between ocular trauma and workplace (Chi-square = 43.80, P < 0.001), and between blindness and place (Chi-square = 9.98, P = 0.041) and source (Chi-square = 10.88, P = 0.028) of ocular trauma. No association was found between visual outcome and the time interval between trauma and first consultation (Chi-square = 0.50, P = 0.78), between receiving treatment and the best corrected visual acuity (Chi-square = 0.81, P = 0.81), and between the person consulted and blinding ocular trauma (Chi-square = 1.88, P = 0.170).

Conclusion:

A significant burden of ocular trauma in the community requires that its prevention and early management be a public health priority.

A comparison of the circadian rhythm of intraocular pressure in primary phronic angle closure glaucoma, primary open angle glaucoma and normal eyes

PURPOSE

To evaluate the circadian rhythm of intraocular pressure (IOP) in primary chronic angle closure glaucoma (PCACG), primary open angle glaucoma (POAG), and normal eyes.

METHODS

Cross-sectional study of newly diagnosed patients of POAG (60 eyes), PCACG following laser iridotomy (75 eyes), and age and sex matched normal controls (75 eyes). All subjects underwent applanation tonometry at 7 a.m., 10 a.m., 1 p.m., 4 p.m., 7 p.m., and 10 p.m. by a masked observer. Circadian rhythms were classified based upon the timing and presence of peak pressure.

RESULTS

Age and gender in all three groups were comparable. Diurnal IOP fluctuations were significantly higher in PCACG (7.69+3.03 mmHg) and POAG (8.31+2.58 mmHg) groups compared to normal controls (4.83 + 2.46 mmHg). PCACG eyes and controls had similarly timed circadian rhythms, with PCACG eyes having a consistently higher IOP. At 7 and 10 a.m., IOP peaked more often in POAG eyes compared to PCACG eyes. A plateau type of circadian rhythm was most common in normal eyes. The timing of peak IOP could be significantly correlated with the type of primary glaucoma examined.

CONCLUSION

Afternoon peaks were more common in postiridotomy PCACG eyes, similar to the rhythm in normal eyes. Morning peaks were more frequent in POAG eyes. Diurnal fluctuation > 6 mmHg, associated with an IOP of 21 mmHg or more was never seen in a normal eye.

Comparative study of vitrectomy for dropped nucleus with and without the use of perfluorocarbon liquid. Clinical, electrophysiological and visual field outcomes

PURPOSE

To compare pars plana vitrectomy for dropped nucleus with and without perfluorocarbon liquid.

METHODS

24 eyes with dropped nucleus were randomized to undergo PPV with perfluorodecalin, (study, n=12) and without it (control, n=12). Visual acuity, IOP, visual evoked response and electroretinography were noted at study entry and up to 3 months after PPV. Humphrey perimetry was done at 3 months.

RESULTS

Final visual acuity was >20/60 in 75% of study eyes and 41.6% of controls. The two groups were statistically comparable with regard to the above parameters before PPV and during follow-up. The timing of vitrectomy did not significantly influence the final visual acuity. A higher rate of complications was seen in the control group.

CONCLUSIONS

Perfluorodecalin facilitated the procedure and possibly minimized complications, and was found to be safe for intraoperative use in terms of recovery of visual acuity, stable ERG and VER, and normal visual fields.