Farm typology for planning targeted farming systems interventions for smallholders in Indo-Gangetic Plains of India.

Due to complexity of smallholder farms, many times technologies with great potential fail to achieve the desired impact in leveraging productivity and profitability of the farming community. In the Indo-Gangetic Plains there is an urgent need to understand the diversity of farm households, identifying the main drivers deciding their system thus, classifying them into homogenous groups. In the present study, the diversity of smallholder farms was assessed using crop, livestock and income related characteristics and associated farm mechanization. Using principal component analysis and cluster analysis for 252 farm households, 4 farm types were identified i.e. Type 1. Small Farm households with cereal-based cropping system and subsistence livestock (39%), Type 2. Small Farm households with diversified cropping system dominated by cereal and fodder crops with only cattle herd (9%), Type 3. Marginal Farm household with diversified cropping system dominated by cash crop and herd comprising of only cattle (39%), Type 4. Marginal Farm household with diversified cropping system dominated by cereal crops and herd dominated by small ruminants (12%). Based on the constraints identified for different components of farming systems, low-cost interventions were planned for each farm type. These interventions have resulted in 84.8-103.2 per cent increase in the income of the farm HH under study suggesting usefulness of typology-based intervention planning in increasing income of small farm holders.

Long-term fertilization and manuring with different organics alter stability of carbon in colloidal organo-mineral fraction in soils of varying clay mineralogy.

Majority of organic matter is bound to clay minerals to form stable colloidal organo-mineral fraction (COMF) in soil. Stability of carbon (C) in COMF is crucial for long-term C sequestration in soil. However, information on the effect of long-term fertilization and manuring with various organic sources on C stability in such fraction in soils with varying clay mineralogy is scarce. The present study was, therefore, carried out to assess the effect of thirty-one years of continuous fertilization and manuring with different organics on C-stability in COMF extracted from an Inceptisol, a Vertisol, a Mollisol, and an Alfisol. The treatments comprised of control (no fertilization), 100% NPK (100% of recommended N, P and K through fertilizer), 50% NPK+ 50% of recommended N supplied through either farm yard manure (FYM) or cereal residue (CR) or green manure (GM). The stability of C (1/k) in COMF was determined from desorption rate constant (k) of humus-C by sequential extraction and correlated with extractable amorphous Fe-Al-Si-oxides, and crystallite size of illite minerals. Long-term fertilization and manuring with the above sources of organic altered the contents of amorphous Fe-Al-Si-oxides, and decreased the crystallite size of illite in all the soil orders. Fifty percent substitution of fertilizer N by various organics significantly increased C-stability in COMF by 27-221% (mean 111%) over full dose of NPK (100% NPK). Smectite dominating Vertisol exhibited highest stability of C followed by the Mollisol, the Inceptisol and the Alfisol. Stability of such C in soil was correlated positively with the amount of amorphous Fe and Al oxides but negatively with crystallite size of illite (r = -0.46, P < 0.01). Application of NPK + GM or NPK + FYM in Inceptisol, Vertisol and Mollisol and NPK + GM or NPK + CR in Alfisol emerged as the best management practices for higher stabilization of C in COMF for long-term C sequestration.

Plant Pathogenic Microbial Communication Affected by Elevated Temperature in Pectobacterium carotovorum subsp. carotovorum.

Gram-negative plant pathogenic bacteria regulate specific gene expression in a population density-dependent manner by sensing level of Acyl-Homoserine Lactone (HSL) molecules which they produce and liberate to the environment, called Quorum Sensing (QS). The production of virulence factors (extracellular enzyme viz. cellulase, pectinase, etc.) in Pectobacterium carotovorum subsp. carotovorum (Pcc) is under strong regulation of QS. The QS signal molecule, N-(3-oxohexanoyl)-L-Homoserine Lactone (OHHL) was found as the central regulatory system for the virulence factor production in Pcc and is also under strict regulation of external environmental temperature. Under seven different incubation temperatures (24, 26, 28, 30, 33, 35, and 37 °C) in laboratory condition, highest amount of OHHL (804 violacein unit) and highest (79 %) Disease Severity Index (DSI) were measured at 33 °C. The OHHL production kinetics showed accumulation of highest concentration of OHHL at late log phase of the growth but diminution in the concentration occurred during stationary phase onwards to death phase. At higher temperature (35 and 37 °C) exposure, OHHL was not at detectable range. The effect of temperature on virulence factor production is the concomitant effect of HSL production and degradation which justifies less disease severity index in cross-inoculated tomato fruits incubated at 35 and 37 °C. The nondetection of the OHHL in the elevated temperature may because of degradation as these signal molecules are quite sensitive and prone to get degraded under different physical factors. This result provides the rationale behind the highest disease severity up to certain elevated temperature and leaves opportunities for investigation on mutation, co-evolution of superior plant pathogen with more stable HSL signals-mediated pathogenesis under global warming context.

Comparative evaluation of two Trichoderma harzianum strains for major secondary metabolite production and antifungal activity.

This investigation was undertaken to identify the major secondary metabolite, produced by two Trichoderma harzianum strains (T-4 and T-5) with their antifungal activity against phytopathogenic fungi using poison food technique. The ethyl acetate extract was subjected to column chromatography using n-hexane, ethyl acetate and methanol gradually. Chromatographic separation of ethyl acetate extract of T. harzianum (T-4) resulted in the isolation and identification of palmitic acid (1), 1,8-dihydroxy-3-methylanthraquinone (2), 6-pentyl-2H-pyran-2-one (3), 2(5H)-furanone (4), stigmasterol (5) and ß-sitosterol (6), while T. harzianum (T-5) gave palmitic acid (1), 1-hydroxy-3-methylanthraquinone (7), δ-decanolactone (8), 6-pentyl-2H-pyran-2-one (3), ergosterol (9), harzianopyridone (10) and 6-methyl-1,3,8-trihydroxyanthraquinone (11) as major metabolites. Among compounds screened for antifungal activity, compound 10 was found to be most active (EC50 35.9-50.2 µg mL(-1)). In conclusion, the present investigation provided significant information about antifungal activity and compounds isolated from two different strains of T. harzianum obtained from two different Himalayan locations.

Influence of diabetes and diabetes type on anatomic and visual outcomes following central rein vein occlusion.

PURPOSE: To determine the influence of diabetes and diabetes type on ocular outcomes following central retinal vein occlusion (CRVO). METHODS: Retrospective chart review of all patients evaluated over a 4-year period in a tertiary diabetes eye care center. Ophthalmic findings were recorded including visual acuity and the presence of retinal neovascularization at presentation, after 3-6 months, and at last follow-up. RESULTS: The records of 19,648 patients (13,571 diabetic; 6077 nondiabetic) were reviewed. The prevalence of CRVO in diabetic patients (N=72) and nondiabetic patients (N=27) were 0.5 and 0.4%, respectively. Disc neovascularization (21.3 vs 0.0%, P=0.05) and panretinal photocoagulation (PRP) (48.7 vs 21.4%, P=0.01) were more common in diabetic patients compared with nondiabetic patients. Compared with type 2 diabetic patients, retinal neovascularization (28.6 vs 3.7%, P=0.004) and subsequent PRP (78.6 vs 41.9%, P=0.01) were more likely in type 1 patients. Optic nerve head collateral vessels (CVs) were observed less than half as often (21.4 vs 56.5%, P=0.04) in patients with type 1 diabetes. Presence of optic nerve head CVs at baseline was associated with less likelihood of PRP (14.3 vs 46.1%, P=0.03). CONCLUSIONS: In this cohort, the rates of CRVO in diabetic and nondiabetic patients were similar to previously published population-based studies. Following CRVO, diabetic patients had higher rates of disc neovascularization and were more likely to require subsequent PRP than nondiabetic patients. As compared with CRVO patients with type 2 diabetes, patients with type 1 diabetes and CRVO had worse anatomic outcomes with substantially increased risks of retinal neovascularization and PRP; however, final visual acuity outcomes were similar.

Release kinetics of controlled release formulations of thiamethoxam employing nano-ranged amphiphilic PEG and diacid based block polymers in soil.

Amphiphilic copolymers, synthesized from poly(ethylene glycols) and various aliphatic and aromatic diacids, which self-assemble into nanomicellar aggregates in aqueous media, were used to develop controlled release (CR) formulations of thiamethoxam (3-(2-chloro-1,3-thiazol-5-ylmethyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene(nitro)amine) using encapsulation technique Formulations were characterised by Infrared (IR) spectroscopy, Dynamic Light Scattering (DLS) and Transmission Electron Microscope (TEM). Encapsulation efficiency, loading capacity and stability after accelerated storage test of the developed formulations were checked. The kinetics of thiamethoxam, released in sandy loam soil from the different formulations was studied. Release from the commercial formulation was faster than the CR formulations. The time taken for release of 50 % of thiamethoxam ranged from 3.56 to 6.07 days for the CR formulations. Although the diffusion exponent (n value) of thiamethoxam in soil ranged from 0.532 to 0.881 in the tested formulations showing non-Fickian transport. These CR formulations may be used in safer, effective and economic crop protection.

Development of controlled release formulations of imidacloprid employing novel nano-ranged amphiphilic polymers.

Amphiphilic copolymers, synthesized from poly (ethylene glycols) and various aliphatic diacids, which self assemble into nano-micellar aggregates in aqueous media, were used to develop controlled release (CR) formulations of imidacloprid [1-(6 chloro-3-pyridinyl methyl)-N-nitro imidazolidin-2-ylideneamine] using encapsulation technique. High solubilisation power and low critical micelle concentration (CMC) of these amphiphilic polymers may increase the efficacy of formulations. Formulations were characterised by Infrared (IR) spectroscopy, Dynamic Light Scattering (DLS) and Transmission Electron Microscope (TEM). Encapsulation efficiency, loading capacity and stability after accelerated storage test of the developed formulations were checked. The kinetics of imidacloprid release in water from the different formulations was studied. Release from the commercial formulation was faster than the CR formulations. The diffusion exponent (n value) of imidacloprid, in water ranged from 0.22 to 0.37 in the tested formulations. While the time taken for release of 50 % of imidacloprid ranged from 2.32 to 9.31 days for the CR formulations. The developed CR formulations can be used for efficient pest management in different crops.

Residue and bio-efficacy evaluation of controlled release formulations of imidacloprid against pests in soybean (Glycine max).

Controlled release (CR) formulations of imidacloprid (1-(6 chloro-3-pyridinyl methyl)-N- nitro imidazolidin-2- ylideneamine) were prepared using novel amphiphilic polymers synthesized from polyethylene glycol and aliphatic diacids employing encapsulation technique. The bioefficacy of the prepared CR formulations was evaluated against major pests of soybean, namely stem fly, Melanagromyza sojae Zehntmer and white fly, Bemisia tabaci Gennadius along with a commercial formulation at the experimental farm of Indian Agricultural Research Institute (IARI), New Delhi during kharif 2009 and 2010. Most of the CR formulations of imidacloprid gave significantly better control of the pests compare to its commercial formulations, however the CR formulations, Poly [poly (oxyethylene-1000)-oxy suberoyl] amphiphilic polymer based formulation performed better over others for controlling of both stem fly incidence and Yellow Mosaic Virus (YMV) infestation transmitted by white fly. Some of the developed CR formulations recorded higher yield over commercial formulation and control. Nodulation pattern of soybean was not affected due to treatment of CR and commercial formulations of imidacloprid. Also the residues of imidacloprid in seed and soil at harvest were not detectable for both CR and commercial formulations.

Perceived facilitators and barriers to physical activity for rural youth: an exploratory study using photovoice.

INTRODUCTION: Decreasing physical activity levels, particularly among youth, continue to be a prominent health concern in Canada, and youth living in rural areas may encounter unique facilitators and barriers to physical activity. In addition, current research suggests that overweight and obesity rates are higher for youth in some rural areas compared with urban areas. The goal of this study was to identify the perceived facilitators and barriers to physical activity for a selected sample of rural youth at a rural secondary school in south-western Ontario and examine how rural barriers and facilitators affect rural youth physical activity. Current Canadian literature addresses rural youth physical activity in a very limited fashion. Thus, the goal of this research was to provide important insights into physical activity for rural youth. METHOD: Nine participants aged 13 to 18 years completed the study using the photovoice methodology and method. Photovoice is a relatively new method for health research that adopts an innovative approach whereby participants use cameras to document their perceived health realities. In photovoice the images and words from the life experiences of participants create the basis for discussion. Participants had 2 weeks to take photographs. After 2 weeks the cameras and logbooks were retrieved, the photographs were developed, and a one-on-one interview was held with each participant. The interviews focused on participants' explanations of their photographs and their relevance to physical activity. RESULTS: Analysis of the pictorial, narrative, and logbook data provided by participants revealed 12 themes as facilitators and barriers to physical activity. Some of the themes relate to facilitators (eg early exposure to activities), some to barriers (eg lack of opportunities close to home), and some themes represent both a facilitator and a barrier (eg competitiveness, family support, and peer interests). The findings of this study may assist community stakeholders, school officials, and parents to better support the physical activity needs of rural youth. CONCLUSIONS: Physical activity rates continue to decline and to be a major health concern for Canadian youth. Thus, it is becoming increasingly important to understand physical activity from the perspective of rural youth. Implications of this information for rural communities, rural schools, and rural residents are significant. These implications and recommendations may help facilitate increased participation in physical activity for rural youth by providing them, and their families and communities, with enhanced opportunities and resources to engage in physical activity. Further research is clearly indicated.

Isolation of Tn1546-like elements in vancomycin-resistant Enterococcus faecium isolated from wood frogs: an emerging risk for zoonotic bacterial infections to humans.

AIM: Isolation and characterization of vancomycin-resistant enterococci (VRE), mainly Enterococcus faecium, from the faecal pellet of wood frogs (Rana sylvatica). METHODS AND RESULTS: The frog VRE isolates were tested for their susceptibility to various antibiotics and were found resistant to ampicillin (Am), chloramphenicol (Cm), erythromycin (Em), gentamicin (Gm), tetracycline (Tc), teicoplanin (Tp) and vancomycin (Vn). The linkage of multiple antibiotic resistances to Em, Tc, Tp and Vn was observed in 84% of resistant Ent. faecium. Inducible antibiotic resistance (MIC ≥ 512 µg ml(-1) ) to Vn was also detected in these isolates. PCR analysis revealed the presence of vanA in all strains, and none of the strains were positive for vanB, indicating the existence of vanA phenotype. Furthermore, the PCR-RFLP analysis of the frog vanA amplicon with PstI, BamHI and SphI generated identical restriction patterns similar to Tn1546-like elements found in human VRE isolates. DNA homoduplex analysis also confirmed that vanA from the frog VRE has DNA sequence homology with the vanA of Tn1546-like elements of human and animal isolates. Blastx analysis of frog vanA sequence showed similarities with protein sequences generated from protein database of Vn-resistant Ent. faecium, Baccilus circulans, Paenibacillus apiarius and Oerskovia turbata isolates. Horizontal transfer of Vn resistance was not detected in frog isolates as revealed by filter mating conjugal experiment. CONCLUSIONS: In summary, our results demonstrated that wood frogs carry Vn-resistant bacteria, and resistance genes (vanA) are located on Tn1546-like elements. SIGNIFICANCE AND IMPACT OF THE STUDY: This study highlights a previously less recognized role of amphibians as sentinels for multidrug-resistant bacteria and alerts the public health workers for an emerging risk of zoonotic bacterial infections to humans.

Prevalence of cystic macular lesions in patients with Usher II syndrome.

PURPOSE: To evaluate the prevalence of cystic macular lesions in patients with Usher II syndrome. METHODS: All Usher type II patients seen in the inherited eye disease clinic at the University of Illinois at Chicago between January 2002 and December 2007 were included (n=76). Each participating patient underwent a detailed clinical examination, including best-corrected visual acuity, slit-lamp biomicroscopy and dilated fundus examination. The presence of cystoid lesions was determined by optical coherence tomography (OCT), fundus fluorescein angiogram (FFA), fundus photographs and/or clinical examination. RESULTS: A cystic-appearing macular change was observed in at least one eye in 19 out of the 76 patients (25%), 13 on the basis of OCT, five using FFA (two solely with the use of FFA and three based on clinical notes and FFA findings) and one based solely on clinical notes. Of the 18 patients with CME, determined by OCT or FFA, five (27.8%) showed either a funduscopically normal-appearing macula (n=4) or an atrophic appearing macular change (n=1). CONCLUSIONS: One-fourth of our total cohort of Usher II patients had cystic macular lesions. Moreover, a funduscopically normal-appearing macula was observed in 22% (n=4) of our 18 patients with cystic-appearing macular lesions on OCT and/or FFA testing. On the basis of the reasonably high prevalence of cystic macular lesions in our cohort, it would seem prudent to evaluate Usher II patients for the presence of cystoid macular oedema.

Variation in intubation decisions for patients with chronic obstructive pulmonary disease in one critical care network.

BACKGROUND: Anecdotal evidence suggests variation in intubation decisions for chronic obstructive pulmonary disease (COPD) patients with respiratory failure, but little is known about the extent of or reasons for this variability. AIM: To describe clinician decision-making for patients with exacerbations of COPD considered for intubation. DESIGN: Telephone simulation study. METHODS: Consultants responsible for COPD admissions in the Heart of England Critical Care network were asked to decide whether or not to admit three patients with COPD to ICU on the basis of information conveyed over the telephone. Consultants were also asked to predict patients survival in ICU hospital and at 180 days on the assumption that the patient did receive ICU care. RESULTS: Of the 120 consultants, 98 (82%) took part; 89% would admit patient 1, 64% patient 2, and 40% patient 3. The prediction of survival if ICU admission had occurred differed significantly between admitters and non-admitters. Mean predicted post-ICU hospital survival for patient 1 was 46% (95%CI 43-49) for admitters, and 13% (95%CI 6-19) for non-admitters (p < 0.001). The respective figures for patient 2 were 38% (95%CI 34-42) vs. 12% (95%CI 8-15) (p < 0.001), and for patient 3, 28% (95%CI 24-33) vs. 13% (95%CI 10-16) (p < 0.001). For a housebound COPD patient in their mid 70s, the mean (SD) threshold of predicted hospital survival below which consultants would recommend not admitting to ICU was 22% (13.2%). CONCLUSIONS: Consultants differed markedly in their admitting decisions about identical patients. Objective outcome prediction models might improve equity in ICU bed use for patients with COPD.

Some furfural derivatives as nitrification inhibitors.

Three series of furfural derivatives, namely N-O-furfural oxime ethers, furfural Schiff bases (furfurylidene anilines), and furfural chalcones, have been synthesized and evaluated for nitrification inhibition activity in laboratory incubation studies in typic Ustocrept soil. Furfural oxime ethers and furfural Schiff bases showed potential activity, but furfural chalcones were only mildly active. N-O-ethyl furfural oxime among the oxime ethers, and furfurylidine-4-chloroaniline among the furfural Schiff bases, performed the best. These two compounds showed more than 50% nitrification inhibition on the 45th day at 5% dose as compared to 73% inhibition by nitrapyrin. Activity of furfural oxime ethers decreased with an increase in carbon atoms in the N-O-alkyl side chain. Introduction of a chlorine atom in the phenyl ring of furfurylidene anilines increased the persistence of their activity. N-O-Ethyl furfural oxime and furfurylidine-4-chloroaniline coated urea performed at par with their application in solution form. Ethyl and N-O-isopropyl oxime, as well as chloro- and nitro- substituted Schiff bases, did not reveal any phytotoxicity (adverse effect on germination) on chickpea seeds (Cicer arietinum) even at the highest dose (40 ppm, soil basis).

Insect growth inhibition, antifeedant and antifungal activity of compounds isolated/derived from Zingiber officinale Roscoe (ginger) rhizomes.

Fresh rhizomes of Zingiber officinale (ginger), when subjected to steam distillation, yielded ginger oil in which curcumene was found to be the major constituent. The thermally labile zingiberene-rich fraction was obtained from its diethyl ether extract. Column chromatography of ginger oleoresin furnished a fraction from which [6]-gingerol was obtained by preparative TLC. Naturally occurring [6]-dehydroshogaol was synthesised following condensation of dehydrozingerone with hexanal, whereas zingerone and 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)butane were obtained by hydrogenation of dehydrozingerone with 10% Pd/C. The structures of the compounds were established by 1H NMR, 13C NMR and mass (EI-MS and ES-MS) spectral analysis. The test compounds exhibited moderate insect growth regulatory (IGR) and antifeedant activity against Spilosoma obliqua, and significant antifungal activity against Rhizoctonia solani. Among the various compounds, [6]-dehydroshogaol exhibited maximum IGR activity (EC50 3.55 mg ml-1), while dehydrozingerone imparted maximum antifungal activity (EC50 86.49 mg litre-1).

Cutaneous CO2 laser resurfacing infection rate with and without prophylactic antibiotics.

BACKGROUND: Cutaneous laser resurfacing is a well-accepted modality, with excellent clinical outcomes and low morbidity rates, for the treatment of a variety of epidermal and dermal lesions. The use of antibiotic prophylaxis continues to be an area of controversy, with laser practitioners divided in their approach. OBJECTIVE: To identify the rate of postoperative bacterial infection following full-face carbon dioxide (CO2) laser resurfacing with and without antibiotic prophylaxis. METHODS: A retrospective chart review of 133 consecutive patients following full-face CO2 laser resurfacing was performed. The rate, severity, duration, and subsequent treatment of bacterial infections observed in four treatment categories were recorded: (1) no antibiotic prophylaxis; (2) intraoperative single-dose intravenous cephalexin (1 g); (3) postoperative oral azithromycin (1.5 g over 5 days); (4) intraoperative IV cephalexin (1 g) and postoperative oral azithromycin (1.5 g). RESULTS: A significantly higher rate of infection occurred in patients receiving combination intraoperative and/or postoperative antibiotic prophylaxis. The most frequently cultured organisms included Enterobacter and Pseudomonas species. CONCLUSION: The rate of postoperative bacterial infections after full-face CO2 laser resurfacing in this retrospective study was not significantly reduced with the use of prophylactic antibiotics.

Prolonged clinical and histologic effects from CO2 laser resurfacing of atrophic acne scars.

BACKGROUND: The recent development of high-energy pulsed CO2 lasers that minimize thermal injury to uninvolved adjacent structures has revolutionized the manner in which atrophic facial scars are recontoured. Significant improvement of atrophic scars with laser resurfacing has clearly been demonstrated; however, the exact timing for assessment of skin for further treatment has varied due to the unknown amount of time needed after laser scar resurfacing to effect maximal collagen formation and remodeling. OBJECTIVE: The aim of this study was to determine the immediate and long-term (12-18 months) histologic and clinical effects of atrophic acne scars after CO2 laser resurfacing in order to provide physician guidelines for postoperative clinical assessment for retreatment. METHODS: Sixty patients (50 women, 10 men, mean age 38 years, skin types I-V) with moderate to severe atrophic facial scars were evaluated. Nineteen patients received regional cheek treatment and 41 patients received full-face resurfacing with a high-energy pulsed CO2 laser. Independent clinical assessments of treated scars were performed at 1, 6, 12, and 18 months and blinded histologic analyses were made of skin biopsies immediately prior to and after laser resurfacing, and at 1, 6, 12, and 18 months postoperatively in six patients. RESULTS: Significant immediate and prolonged clinical improvement in skin tone, texture, and appearance of CO2 laser-irradiated scars was seen in all patients. Average clinical improvement scores were 2.22 (69%) at 1 month, 2.1 (67%) at 6 months, 2.37 (73%) at 12 months, and 2.5 (75%) at 18 months. Continued collagenesis and subsequent dermal remodeling were observed on histologic examination of biopsied tissue up to 18 months after surgery. CONCLUSION: Continued clinical improvement was observed as long as 18 months after CO2 laser resurfacing of atrophic scars, with an 11% increase in improvement observed between 6 and 18 months postoperatively. We propose that a longer postoperative interval (12-18 months) prior to assessment for re-treatment be advocated in order to permit optimal tissue recovery and an opportunity for collagen remodeling.

Synthesis and Insect Growth Regulatory Activity of Alkoxy-Substituted Benzaldoxime Ethers.

Alkoxy-substituted benzaldoxime ethers, namely (i) 3-methoxy-4-ethoxybenzaldoxime N-O-alkyl ethers, (ii) 3,4-dimethoxybenzaldoxime N-O-alkyl ethers, and (iii) 3,4-methylenedioxybenzaldoxime N-O-alkyl ethers, have been synthesized and evaluated for their insect growth regulatory activity against fifth-instar nymphs of the desert locust Schistocerca gregaria F. When injected into insect hemolymph at the lowest dose level of 3 µg/nymph, 3,4-methylenedioxybenzaldoxime N-O-methyl ether and 3,4-methylenedioxybenzaldoxime N-O-isopropyl ether showed 40 and 50% growth deformities respectively. On topical application (at 20 µg/nymph) 3-methoxy-4-ethoxybenzaldoxime N-O-methyl ether inflicted 100% abnormalties in insect growth. Structure-activity relationship studies revealed that maximum activity was associated with compounds having three carbons in the oxime ether moiety.

Characterization by arbitrary primer polymerase chain reaction of polychlorinated biphenyl (PCB)-degrading strains of Comamonas testosteroni isolated from PCB-contaminated soil.

In this study, we isolated and characterized biphenyl (BP) and polychlorinated biphenyl (PCB) degrading bacterial strains found in PCB-contaminated soil from an auto manufacturing plant located in Syracuse, New York. Twenty-one BP and PCB-degrading bacteria were randomly selected to form a representative sample of the bacterial population present at the site. Of the 21 bacteria, 13 were identified as Comamonas testosteroni, constituting about 60% of the bacterial population examined. Other PCB degraders identified were Acidovorax facilis, Alcaligenes xylosoxydans, Bacillus sphericus, Hydrogenophaga pseudoflava, Pseudomonas avanae, and Rhodococcus fascians. Owing to the abundance of C. testosteroni at this site, only these isolates were further characterized for their PCB congener degradation profile, 2,3-dihydroxybiphenyl 1,2-dioxygenase activity, and genetic relatedness by polymerase chain reaction (PCR) analysis. The PCB congener degradation pattern revealed a high degree of variability among the C. testosteroni isolates. The majority of the C. testosteroni isolates tested could degrade more than 95% of the PCB congeners up to pentachlorinated biphenyl. Only four isolates could degrade more than 80% of hexachlorobiphenyl. All 12 isolates of C. testosteroni tested were able to attack 2,3,4,5,6,3',4'-heptachlorobiphenyl, indicating involvement of biphenyl 2,3-dioxygenase, while 2,3,5,6,2',3',6'-heptachlorobiphenyl was attacked by 6 strains, suggesting an oxidation reaction mediated by 3,4-dioxygenase. 2,3-Dihydroxybiphenyl 1,2-dioxygenase activity was also found to vary among the C. testosteroni isolates tested in this study. Eleven strains showed 2,3-dihydroxybiphenyl 1,2-dioxygenase activity specific for 2,3-dihydroxybiphenyl, whereas isolate BW 169 could metabolize both 2,3-dihydroxybiphenyl and 4-methylcatechol, and isolate BW74 had the ability to metabolize all three substrates (2,3-dihydroxybiphenyl, 4-chlorocatechol, and 4-methylcatechol).(ABSTRACT TRUNCATED AT 250 WORDS)

Genotoxicity of polychlorinated biphenyls (PCBs): recombinogenesis by biotransformation products.

A coplanar polychlorinated biphenyl (PCB) when eaten by test animals increased the rate of recombination in somatic cells, indicating a new mechanism of action for these compounds. Using the eye-mosaic test a high bioactivation strain of Drosophila that consumed 4,4'-dichlorobiphenyl (4,4'-DCB) manifested a genotoxicity rate that was three-fold greater than that in animals fed the solvent-spiked medium. This compound was not genotoxic in a suppressed bioactivation strain indicating that genotoxicity requires bioactivation of the compound. High bioactivation test strains made heterozygous for a paracentric inversion, a chromosomal rearrangement that suppresses homologous recombination, exhibited significantly reduced genotoxicity after treatment.