In situ bioremediation of organochlorine-pesticide-contaminated microcosm soil and evaluation by gene probe

BACKGROUND

Pesticide-formulating industries are contaminating the environment through various activities. Bioremediation is the best method for decontamination, as chemical and physical methods are not only costly but also not very effective in open field systems. In the present study, in situ bioremediation of organochlorine-contaminated soil was demonstrated by combined biostimulation and bioaugmentation strategies, followed by evaluation using a molecular method.

RESULTS

Three parameters were monitored: microbial biomass (colony-forming units (CFU) g(-1) soil), residual pesticides after treatment and catabolic genes from microcosm soil. Both the biostimulation and the bioaugmentation treatments showed an initial lag phase of 80 days towards colony-forming units. Gas chromatography of soil samples showed that concentrations of residual pesticides in the soil declined by up to 85-90% after 80 days, indicating their utilisation with time. On dot-blot hybridisation of the total DNA from the same soil samples, it was observed that catabolic genes tfdC (catechol 1,2-dioxygenase) and cm genes (chlorophenol monoxygenase) were predominant, whereas other catabolic genes such as catechol 2,3-dioxygenase (xylE) were negligible.

CONCLUSION

The strategy of in situ bioremediation and its evaluation by gene probe and also by conventional methods was demonstrated for organochlorine-pesticide-contaminated soil in open microcosms. It showed that bioaugmentation along with biostimulation was effective, although initial acclimatization for a period of almost 2-3 months was required in the open field systems.

The role of environmental factors and hereditary predisposition in the causation of low myopia

Various environmental factors have been implicated in the etiology of myopia. An attempt was made quantitatively to estimate some such environmental factors, as based on the presence or absence of a family history of myopia. Age range was 10-21 years. The 200 subjects included in the study were further divided according to emmetropia/myopia. The factors studied in the four subgroups were amount of near work done per day, head posture and illumination level while doing near work, acute fevers, chronic illness, acute or recurrent diarrhea, nutritional status, and income levels. A correlation was found between myopia and near work, head posture and income levels.

Management of foreign body aspiration or ingestion in dentistry

Foreign body aspiration or ingestion can be a potential complication during routine dental treatment. The handling of dental objects requires particular care, especially where the patient is supine or semi-recumbent. Dentist must be able to manage emergency situations in which patients accidentally swallow dental instruments or materials during treatment and procedures. This article reviews the complications, management and prevention of aspiration or ingestion of foreign bodies.

Protective antioxidant effect of Centella asiatica bioflavonoids on lead acetate induced neurotoxicity

Lead (Pb) is a neurotoxic heavy metal and children in the developmental stage are particularly susceptible to toxic effects of lead exposure. The brain is the key organ involved in interpreting and responding to potential stressors. Epidemiological investigations have established the relationship between chronic lead exposure and cognitive impairments in young children. Excessive production of radical species plays an important role in neuronal pathology resulting from excitotoxic insults, therefore one plausible neuroprotective mechanism of bioflavonoids is partly relevant to their metal chelating and antioxidant properties. Centella asiatica (CA) is a tropical medicinal plant enriched with bioflavonoids and triterpenes and selenium, reported to rejuvenate the cells and promote physical and mental health. Bioflavonoids are claimed to be exert antimutagenic, neurotrophic and xenobiotics ameliorating and membrane molecular stabilizing effects. The objective of the present work is to study the protective antioxidant effect of pretreatment of CA extract (CAE) on lead acetate induced changes in oxidative biomarkers in the central nervous system (CNS) of mice.

Helicoverpa armigera baseline susceptibility to Bacillus thuringiensis Cry toxins and resistance management for Bt cotton in India

Transgenic cotton that produces insecticidal proteins from Bacillus thuringiensis (Bt), often referred to as Bt cotton, is widely grown in many countries. Bt cotton with a single cry1A gene and stacked also with cry2A gene has provided satisfactory protection against the damage by the lepidopteran bollworms, especially the cotton bollworm, Helicoverpa armigera (Hübner) which is considered as a key pest. The baseline susceptibility of the larvae of H. armigera to Cry1Ac and other toxins carried out in many countries has provided a basis for monitoring resistance. There is no evidence of development of field-level resistance in H. armigera leading to the failure of Bt cotton crop anywhere in the world, despite the fact that Bt cotton was grown on the largest ever area of 12.1 million hectares in 2006 and its cumulative cultivation over the last 11 years has surpassed the annual cotton area in the world. Nevertheless, the Bt resistance management has become a necessity to sustain Bt cotton and other transgenic crops in view of potential of the target insects to evolve Cry toxin resistance.

Cloning and structural analysis of an Indian little millet (Panicum sumatrense) zein-like storage protein: implications for molecular assembly

Zeins are prolamin storage proteins that accumulate in kernel endosperm of several cereals. For cloning of genes coding for zein-like proteins that accumulate in enhanced quantities in the filling stages of little millet (Panicum sumatrense Roth.) developing grains, RT-PCR was performed using specific primers. A 750-bp cDNA was directly sequenced and in silico analysis showed high identity degree to alpha-prolamins. This family is composed of zeins from Zea mays, coixins from Coix lachryma-jobi, and alpha-kafirins from Sorghum bicolor. The putative conserved domain of zein-like proteins was identified by primary structure comparisons. Furthermore, threading analyses indicated that the millet zein-like protein forms an anti-parallel alpha-helical hairpin with two opposite surfaces: one hydrophobic and the other hydrophilic that probably could be involved in protein storage assembly. Knowledge about zein-like alpha-prolamins in little millet will lead to cloning and transfer of this gene to other major food crops, such as cereals and legumes, with inferior nutritional quality for monogastric animals.

Optic disc asymmetry: normal tension glaucoma or a space-occupying lesion?

Optic disc asymmetry is a common finding. In the majority of cases automated visual fields are normal. However, in a minority, a visual field defect may lead to a diagnosis of normal tension glaucoma. Rarely, the optic discs and visual field deteriorate irrespective of the normal or reduced intraocular pressure.

Comparison of two hepatitis B vaccines (GeneVac-B and Engerix-B) in healthy infants in India

Hepatitis B is a major problem in many parts of the world. The WHO has recommended the inclusion of hepatitis B vaccines in routine immunization schedules. We wanted to compare two recombinant hepatitis B vaccines in an infant population for immunogenicity and reactogenicity when given at 6, 10, and 14 weeks of age. One hundred seventy-three infants meeting eligibility criteria were given either GeneVac-B (Serum Institute of India Ltd.) or Engerix-B (GlaxoSmithKline Beecham) in a random fashion. Three 0.5-ml (10-mug) doses of the vaccines were given at 6, 10, and 14 weeks of age along with diphtheria-pertussis (whole cell)-tetanus (DTPw) vaccine. Blood samples were collected at baseline and 1 month after administration of the third dose of the vaccines to measure anti-HBs antibody levels. Seroconversion was defined as a titer of more than 1 x 10(-3) IU/ml, while seroprotection was defined as a titer of more than 10 x 10(-3) IU/ml. Of the GeneVac-B recipients, 98% seroconverted versus 99% of the Engerix-B group. The anti-HBs geometric mean titer was slightly greater for GeneVac-B (229 x 10(-3) IU/ml) than for Engerix-B (167 x 10(-3) IU/ml), but the difference was not significant. The seroprotection rates were similar for both vaccines (96% and 95%, respectively). The most common systemic reaction events were mild to moderate fever, excessive crying, local swelling, rash, and irritability, and the local reactions were redness, induration, and edema, which most probably were caused by the simultaneously administered DTPw vaccine. All events were transient and resolved without sequelae. Reactogenicity was similar for the two vaccines. The present study shows that GeneVac-B is as immunogenic and as well tolerated as Engerix-B when administered with DTPw vaccine at 6, 10, and 14 weeks of age.

Screening and Purification of a Novel Trypsin Inhibitor from Prosopis juliflora Seeds with Activity Toward Pest Digestive Enzymes

Several pests are capable of decreasing crop production causing severe economical and social losses. Aiming to find novel molecules that could impede the digestion process of different pests, a screening of alpha-amylase and trypsin-like proteinase inhibitors was carried out in Prosopis juliflora, showing the presence of both in dry seeds. Furthermore, a novel trypsin inhibitor, with molecular mass of 13,292 Da, was purified showing remarkable in vitro activity against T. castaneum and C. maculatus.

Adhesive small bowel obstruction (ASBO) in children--role of conservative management

Adhesive small bowel obstruction (ASBO) is an annoying postoperative complication. Though the diagnosis can be made easily, the role of conservative management in children is controversial. Hence a study was conducted to determine the role of conservative management, and to identify the factors that can predict / influence the outcome of conservative treatment in children with ASBO. Children admitted with ASBO from 1980 to 2002 (22 year period) formed the material for this study. The data was analyzed with respect to the influence of age at the time of presentation, primary disease for which original laparotomy was done, time interval between the primary surgery and the development of ASBO and the number of laparotomies prior to the development of ASBO on the outcome of conservative management. There were 74 episodes of ASBO in 69 children (Five children had two episodes). Out of 74 episodes, 5 episodes (6.75%) needed immediate laparotomy for suspected gangrene. All others were managed conservatively. Of the 69 episodes managed conservatively, 36 responded to conservative treatment (2-5 days) while 33 required subsequent surgical intervention, with 11 of them requiring bowel resection (two for gangrene and 9 for bowel damage during adhesiolysis) and in the rest 22 cases adhesiolysis. A substantial number of children with ASBO respond well to conservative treatment. Majority of the children developed ASBO within three months after the primary laparotomy. Children below the age of one year (at the time of presentation with ASBO) responded poorly to the conservative management. Children who had primary surgery for Hirschsprung's disease and intussusception also appeared to have responded poorly to conservative management, but statistically not significant. Time interval between the primary surgery and the number of laparotomies before the child developed ASBO did not influence the outcome of conservative management.

Tagging and mapping of a rice gall midge resistance gene, Gm8, and development of SCARs for use in marker-aided selection and gene pyramiding

Using amplified fragment length polymorphisms (AFLPs) and random amplified polymorphic DNAs (RAPDs), we have tagged and mapped Gm8, a gene conferring resistance to the rice gall midge (Orseolia oryzae), a major insect pest of rice, onto rice chromosome 8. Using AFLPs, two fragments, AR257 and AS168, were identified that were linked to the resistant and susceptible phenotypes, respectively. Another resistant phenotype-specific marker, AP19(587), was also identified using RAPDs. SCAR primers based on the sequence of the fragments AR257 and AS168 failed to reveal polymorphism between the resistant and the susceptible parents. However, PCR using primers based on the regions flanking AR257 revealed polymorphism that was phenotype-specific. In contrast, PCR carried out using primers flanking the susceptible phenotype-associated fragment AS168 produced a monomorphic fragment. Restriction digestion of these monomorphic fragments revealed polymorphism between the susceptible and resistant parents. Nucleotide BLAST searches revealed that the three fragments show strong homology to rice PAC and BAC clones that formed a contig representing the short arm of chromosome 8. PCR amplification using the above-mentioned primers on a larger population, derived from a cross between two indica rice varieties, Jhitpiti (resistant parent) and TN1 (susceptible parent), showed that there is a tight linkage between the markers and the Gm8 locus. These markers, therefore, have potential for use in marker-aided selection and pyramiding of Gm8 along with other previously tagged gall midge resistance genes [ Gm2, Gm4(t), and Gm7].

Independent Downstream Gene Expression Profiles in the Presence of Estrogen Receptor α or β1

The two known forms of estrogen receptor (ER), alpha and beta, exhibit differences in structure, affinity for certain ligands, and tissue distribution, suggesting differential roles. It is of interest from several perspectives to determine whether the two receptors elicit similar or differing responses within the same cell type in the presence of the same ligand. To evaluate roles of ER, we have examined responses to estrogen in a rat embryonic fibroblast cell line model, normally naive to ER, engineered to stably express ERalpha or ERbeta. Rat1+ERalpha, Rat1+ERbeta, and precursor Rat1 cell lines were treated with estradiol-17beta (E(2); 1 nM) or an ethanol vehicle for 24 h. Total RNA was extracted, and cDNA generated and subjected to suppression subtractive hybridization (SSH), followed by differential screening using dot blot hybridization. In the presence of ERalpha, products were identified that represent classic responses to E(2), including markers for cell proliferation. In the presence of ERbeta, an alternate transcription profile was observed, including upregulation of pro-alpha-2(I) collagen. These data support a model in which ERalpha and ERbeta regulate unique subsets of downstream genes within a given cell type.

Global gene expression analysis comparing bovine blastocysts flushed on day 7 or produced in vitro

In vitro produced (IVP) bovine embryos have darker cytoplasm, reduced buoyant density, fragile zonae pellucidae, chromosomal abnormalities, higher pregnancy failure rates, and altered gene expression compared to embryos produced in vivo. Characterization of early deviations in gene expression would enable us to better understand the biology of early embryo development and improve in vitro culture systems. Here we compared gene expression between Day 7 blastocysts generated in TCM199 with 5% FBS and Day 7 in vivo derived blastocysts and using suppression-subtractive hybridization (SSH). Pools of 25 embryos for both driver and tester were used in the RNA extraction process. The subtracted products were cloned and subjected to differential hybridization screening analysis. cDNAs were isolated, single-pass sequenced, and subjected to BLAST search. Of 32 in vivo ESTs (expressed sequence tags) that provided sequence information, 30 matched homologous sequences in GenBank. Of 32 in vitro ESTs, 22 provided specific matches while the remaining ten represented novel transcripts. Two in vivo ESTs, galectin-1 and fibronectin, and one in vitro EST, filamin A, were further characterized using real-time quantitative PCR. To further examine the reproducibility of the SSH data, three different pools of embryos with each pool containing ten embryos produced from each of the following production systems, namely, in vivo, IVP in TCM199 with 5% FBS and CR1aa with 5% FBS were used for real-time reverse transcription-polymerase chain reaction (RT-PCR) confirmation studies. Significant increases in the expression level of galectin-1 and fibronectin were observed in the in vivo derived blastocysts compared to blastocysts produced in TCM199 with 5% FBS and CR1aa cultures. No significant difference in filamin A expression was found between blastocysts produced in vivo and those derived from either of the in vitro production systems. We conclude that these techniques are useful to characterize the transcriptome of the early preattachment embryo and observed deviations in mRNA expression may partially explain the differences in quality between in vivo and IVP embryos.

Antimutagenicity of herbal detoxification formula Smoke Shield against environmental mutagens

Smoke Shield is a formulation designed to reduce smoke related mutagenicity and toxicity in the population. Smoke Shield contains a dual extract of turmeric (Curcuma longa) obtained by supercritical CO2 gas extraction and post-supercritical hydroethanolic extraction together with extracts of green tea and other spices, whose presence synergistically increases the activity of turmeric. In the present study we have shown its antimutagenic activity to various environmental mutagens in vitro and in vivo. Smoke Shield was found to produce significant inhibition of mutagenicity to Salmonella typhimurium induced by sodium azide and 4-nitro-0-phenylenediamine (NPD) at a concentration of 2 mg/plate while inhibition to N-methyl-N-nitro N'nitrosoguanidine was less significant. Inhibition was also found to depend upon the strain which was used. Smoke Shield was found to be more effective against mutagens needing metabolic activation such as 2-Acetamidofluorene (2-AAF) and benzo[a]pyrene. Smoke Shield was also found to significantly inhibit the mutagenicity induced by tobacco extract to Salmonella typhimurium TA102. Smoke Shield was also found to inhibit the urinary mutagenicity of rats treated with the benzo[a]pyrene and tobacco extract. Moreover, Smoke Shield administration was found to inhibit the urinary mutagenicity in smokers. These results indicate that Smoke Shield could inhibit mutagenic response in vitro and in vivo produced by several kinds of mutagens present in our atmosphere.

Characterization and comparison of midgut proteases of Bacillus thuringiensis susceptible and resistant diamondback moth (Plutellidae: Lepidoptera)

The midgut proteases of the Bacillus thuringiensis resistant and susceptible populations of the diamondback moth, Plutella xylostella L. were characterized by using protease specific substrates and inhibitors. The midgut contained trypsin-like proteases of molecular weights of 97, 32, 29.5, 27.5, and 25 kDa. Of these five proteases, 29.5 kDa trypsin-like protease was the most predominant in activation of protoxins of Cry1Aa and Cry1Ab. The activation of Cry1Ab protoxin by midgut protease was fast (T(1/2) of 23-24 min) even at a protoxin:protease ratio of 250:1. The protoxin activation appeared to be multi-step process, and at least seven intermediates were observed before formation of a stable toxin of about 57.4 kDa from protoxin of about 133 kDa. Activation of Cry1Aa was faster than that of Cry1Ab on incubation of protoxins with midgut proteases and bovine trypsin. The protoxin and toxin forms of Cry proteins did not differ in toxicity towards larvae of P. xylostella. The differences in susceptibility of two populations to B. thuringiensis Cry1Ab were not due to midgut proteolytic activity. Further, the proteolytic patterns of Cry1A protoxins were similar in the resistant as well as susceptible populations of P. xylostella.

Geographical variation in larval susceptibility of the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) to Bacillus thuringiensis spore-crystal mixtures and purified crystal proteins and associated resistance development in India

The susceptibility of larvae of the diamondback moth, Plutella xylostella Linnaeus to purified crystal proteins and spore-crystal preparations of Bacillus thuringiensis was investigated for 13 populations from seven states in India. The LC50 (microg ml(-1), 48 h) values of Cry proteins for different populations of P. xylostella ranged from 0.14-3.74 (Cry1Aa), 0.007-1.25 (Cry1Ab), 0.18-2.47 (Cry1Ac) and 0.12-3.0 (Cry1C). The LC50 (mg (ai) l(-1), 48 h) of spore-crystal preparations ranged from 0.02-0.98 (HD-1) and 0.06-2.14 (HD-73). Significantly higher LC50 values for all tested toxins and strains were obtained with populations collected from Iruttupallam and Ottanchathiram in the southern state of Tamil Nadu, whereas some of the populations collected from the northern part of India were more susceptible than the susceptible IARI 17-65 population. The high levels of resistance in the Iruttupallam and Ottanchathiram populations to Cry1Ab suggested selection pressure by Cry1Ab, which is the predominant toxin in B. thuringiensis formulations used in India. Cry1Ab was found to be more toxic than the other toxins. The population from Iruttupallam showed increased resistance following selection with Cry1Ab in the laboratory (LC50 from 1.25 to 4.31 microg ml(-1) over two generations) and also showed cross resistance to CrylAa and CrylAc. The resistance to Biobit in the field population from Iruttupallam declined slowly; requiring c. 33 generations for an overall 10-fold decline in LC50 when the insects were reared in the laboratory without exposure to B. thuringensis.

Identification and mapping of an AFLP marker linked to Gm7, a gall midge resistance gene and its conversion to a SCAR marker for its utility in marker aided selection in rice

We have identified an AFLP marker SA598 that is linked to Gm7, a gene conferring resistance to biotypes 1, 2 and 4 of the gall midge ( Orseolia oryzae), a major dipteran pest of rice. A set of PCR primers specific to an RFLP marker, previously identified to be linked to another gall midge resistance gene Gm2, also amplified a 1.5-kb (F8LB) fragment that is linked to Gm7. Gm7 is a dominant gene and non-allelic to Gm2. Hybridization experiments with clones from a YAC library of Nipponbare, a japonica variety, a BAC library of IR-BB21, an indica variety, and cosmid clones encompassing Gm2 from Phalguna, an indica variety, with F8LB and SA598 as probes, revealed that Gm7 is tightly linked to Gm2 and is located on chromosome 4 of rice. SA598 was sequenced and the sequence information was used to design sequence-characterized amplified region (SCAR) primers. The potential use of these SCAR primers in marker-aided selection of Gm7 in a rice breeding program has been demonstrated.