Enhanced lipid accumulation in microalgae through nanoparticle-mediated approach, for biodiesel production: A mini-review

Nanoparticle application in microalgae for enhanced lipid production is an ongoing work that leads towards the contribution in biodiesel production. During this decade, metal nanoparticles are constantly being reported to have numerous applications in diverse fields, because of their unique optical, electrical, and magnetic properties. They can interact with the biomolecules of cells and thereby alters cellular metabolisms, which in turn reflects their ability to regulate some primary or secondary metabolic pathways. Nanoparticles derived from metals like Fe, Cu, and Se are taking part in redox processes and their presence in many enzymes may modulate algal metabolisms. Besides by upregulating or downregulating the expression of several genes, nanoparticle exposure can alter gene expressions in many organisms. In microalgae such as Chlorella vulgaris, C. pyrenoidosa, Scenedesmus obliquus, S. rubescens, Trachydiscus minut u s, Parachlorella kessleri, and Tetraselmis suecica; metal nanoparticle exposure in different environmental conditions have impacts on various physiological or molecular changes, thereby increasing the growth rate, biomass and lipid production. The present mini-review gives an insight into the various advantages and a future outlook on the application of nanoparticles in microalgae for biofuel production. Also, it can be proposed that nanoparticles could be useful in blocking or deactivating the AGPase enzyme (involved in the glucose to starch conversion pathway), binding to its active site, thereby increasing lipid production in microalgae that could be utilized for enhanced biodiesel production.

The report of anthocyanins in the betalain-pigmented genus Hylocereus is not well evidenced and is not a strong basis to refute the mutual exclusion paradigm

Here we respond to the paper entitled "Contribution of anthocyanin pathways to fruit flesh coloration in pitayas" (Fan et al., BMC Plant Biol 20:361, 2020). In this paper Fan et al. 2020 propose that the anthocyanins can be detected in the betalain-pigmented genus Hylocereus, and suggest they are responsible for the colouration of the fruit flesh. We are open to the idea that, given the evolutionary maintenance of fully functional anthocyanin synthesis genes in betalain-pigmented species, anthocyanin pigmentation might co-occur with betalain pigments, as yet undetected, in some species. However, in absence of the LC-MS/MS spectra and co-elution/fragmentation of the authentic standard comparison, the findings of Fan et al. 2020 are not credible. Furthermore, our close examination of the paper, and re-analysis of datasets that have been made available, indicate numerous additional problems. Namely, the failure to detect betalains in an untargeted metabolite analysis, accumulation of reported anthocyanins that does not correlate with the colour of the fruit, absence of key anthocyanin synthesis genes from qPCR data, likely mis-identification of key anthocyanin genes, unreproducible patterns of correlated RNAseq data, lack of gene expression correlation with pigmentation accumulation, and putative transcription factors that are weak candidates for transcriptional up-regulation of the anthocyanin pathway.

Antibacterial and biofilm inhibition activity of biofabricated silver nanoparticles against Xanthomonas oryzae pv. oryzae causing blight disease of rice instigates disease suppression

Antimicrobial activity of silver nanoparticles (AgNPs) has been well documented in earlier studies. As their efficient role in combating phytopathogens has begun recently, there is a huge scope to explore their effectiveness in agriculture. Considering the strong antifungal activity of biosynthesized AgNPs (as reported in our previous study), our main aim is to elucidate their antibacterial activity against bacterial plant pathogens to authenticate their wide range of agricultural applications. The present manuscript highlights the potential role of biosynthesized AgNPs against Xanthomonas oryzae pv. oryzae (Xoo) causing disastrous sheath blight disease of rice worldwide. We observed strong antibacterial activity of biosynthesized AgNPs (size ~ 12 nm) against Xoo at 20, 30 and 50 µg/mL concentrations. The significant inhibitory impact of AgNPs on biofilm formation by Xoo was noted even at the lower dose of 5 µg/mL (p = 0.001). Maximum biofilm inhibition (p = 0.000) was caused at 50 µg/mL concentration of AgNPs in comparison to control. Furthermore, disease suppression by biosynthesized AgNPs was authenticated under greenhouse conditions. Foliar spray of AgNPs significantly reduced the blight symptoms in rice sheaths as shown by 9.25% DLA (% Diseased leaf area) as compared to 33.91% DLA in Xoo inoculated rice plants. Altogether, our data suggest that biosynthesized AgNPs based nanoformulation can be applied for successful management of blight disease of rice. In addition, the antibiofilm strategies instigated by AgNPs can be exploited against a wide range of bacterial phytopathogens. In light of rapidly emerging antibiotic-resistant microbial strains, the current work provides an alternate effective platform for the application of nanoformulation for augmenting sustainability in the agriculture.

Silver nanoparticles mediated altered gene expression of melanin biosynthesis genes in Bipolaris sorokiniana

Melanin production in many fungal phytopathogens has been investigated to play direct or indirect role in pathogenesis. However, in Bipolaris sorokiniana, the spot blotch pathogen of wheat, much less is known about the role melanin play in pathogenesis. As an extension of our previous report, the present study aims to investigate the plausible association between melanin production and virulence factor in B. sorokiniana. In the previous study, we carried out analysis on the antifungal efficacy of biosynthesized silver nanoparticles (AgNPs) against B. sorokiniana. The present investigation revealed the gene expression analysis of melanin biosynthesis genes viz. polyketide synthase (PKS1) and scytalone dehydratase (SCD1) under the influence of AgNPs. The 0.05mg/ml concentration of AgNPs yielded noticeable inhibition of B. sorokiniana growth, while 0.1mg/ml concentration of AgNPs accounted for complete inhibition of pathogen growth. In addition, the semiquantitative RT-PCR analysis exhibited reduced expression of PKS1 and SCD1 under the influence of AgNPs treatment. Furthermore, the qRT-PCR demonstrated 6.47 and 1.808 fold significant decrease in the expression pattern of PKS1 and SCD1, respectively, in B. sorokiniana treated with AgNPs. The present study provides probable understanding of molecular events underlying the antifungal role of AgNPs against B. sorokiniana.

Effect of mixture of Trichoderma isolates on biochemical parameter in tomato fruits against Sclerotinia sclerotiorum rot of tomato plant

Experiments revealed that a mixture of Trichoderma harzianum isolates, BHU51 and BHU105 showed lowest mean disease rating (MDR) of 1.70 and 1.62% and per cent disease reduction (PDR) by 41.00 and 44.84% during the year 2008-09 and 2009-10, respectively. Shoot length, chlorophyll content and yield was also recorded highest in the mixture of BHU51+ BHU105 treatment followed by single Tichoderma treatments while lowest was found in pathogen inoculated control. The nutritional quality such as lycopene content, protein and carbohydrate was recorded highest in BHU51+ BHU105 treatment. The antioxidant activity and free radical scavenging ability of tomato fruit extract was also recorded. The results indicated that maximum 1,1-diphenyl -2-pycryl-hydrazyl (DPPH) radical scavenging activity (47.86%), ferrous ion chelation capacity (50.81%), hydroxyl radical scavenging ability (49.18%) and reducing power 0.203 O.D. at wavelength 700 nm was maximum for BHU51+ BHU105 treatment, followed by single Trichoderma treated treatments while these were recorded lowest in pathogen inoculated control.

Effect of mixture of Trichoderma isolates on biochemical parameters in leaf of Macrophomina phaseolina infected brinjal

A mixture of Trichoderma harzianum NBRI-1055 (Fx) and T. harzianum BHU-99 (Th) was evaluated for their efficiency to induce systemic resistance during three way interaction among brinjal-Trichoderma-Macrophomina phaseolina. Total phenol content (TPC), defence related enzymes Phenylalanine ammonia-lyase (PAL), Peroxidase (PO), Polyphenol oxidase (PPO) and PR proteins (PR-2 and PR-3) were recorded. Total phenolic content was recorded 12.82 times and 1.8 times higher in Trichoderma mixture treated-pathogen challenge (Fx-Th-Pth) treatment than in untreated healthy control and untreated pathogen challenged (Pth) plants respectively after 72 hr pathogen inoculation (hapi). Defence related enzymes PAL 4.54 times higher, 48hapi, PO, 3.96 times higher, 72hapi and PPO 8.1 times higher, 72hapi in Fx-Th-Pth treatment than untreated healthy control, and the PR- proteins such as PR-2, 2.15 times and PR-3, 2.16 times higher, 72hapi than untreated healthy control. The results showed that a mixture of Trichoderma (Fx+Th) performed better than single isolate.

Molecular, phenotypic and pathogenic variability in Colletotrichum isolates of subtropical region in north-eastern India, causing fruit rot of chillies

AIM

To study the genetic variability and population structure of Colletotrichum species found to be associated with anthracnose of chilli in the north-eastern region of India.

METHODS AND RESULTS

Twenty-three Colletotrichum isolates were obtained from infected chilli fruits and leaves from the chilli growing regions of north-eastern Uttar Pradesh, India, identified as Colletotrichum capsici and Colletotrichum acutatum using species-specific primers. Genetic variability among the isolates was analysed using RAPD and ISSR markers. The RAPD marker efficiently grouped the isolates at species level, while ISSR marker was effective in separating the isolates based on geographical origin. In vitro pathogenic test revealed the inability of C. acutatum isolates to infect unripe fruits, while C. capsici isolates were found to infect both ripe and unripe fruits at disease severity scale 7-9. Growth rate on different media was recorded to cross-confirm the classification of isolates, which clearly grouped the two species into distinct group on PCA plot.

CONCLUSIONS

Two species, viz. C. capsici and C. acutatum, prevalent in the region were found to infect the fruits at postripening stage.

SIGNIFICANCE AND IMPACT OF THE STUDY

The present study proposes the implementation of management strategies at postripening stages of the crop to control the spread of disease, thereby leading to increment in production of chilli in the given region.

Abstract P1-06-11: Tumor-associated macrophages: CD206 expression and patient outcomes in locally advanced breast cancer

Introduction

The ability of a tumor to recur is related to the complex molecular biology of the tumor cells and the surrounding microenvironment. Tumor-associated macrophages (TAMs) account for up to 50% of the cell mass within a breast tumor, and the M2 macrophage phenotype has been reported to have pro-tumor activity. The mannose receptor, CD206, is a transmembrane receptor expressed predominantly in macrophages and shown in mouse studies to promote M2/TAM activity. This study evaluates CD206 expression in the tumor stroma with patient outcomes in locally advanced breast cancer.

Methods

The Scott & White tumor registry was queried for consecutive cases of women diagnosed with stage 3, HER-2 negative breast cancer between January 1999 and December 2006. To meet inclusion criteria, all biopsies must have been performed at S&W and patients must have had at least 5 years of follow up in our system documenting status of cancer (complete remission vs. metastatic recurrence). Archived formalin fixed and paraffin embedded tissue breast tissue from initial surgical biopsies was obtained from the Scott & White Pathology Department. Sections were cut at 4 microns thick and slides were stained for CD206. Two pathologists without knowledge of the patients’ clinical backgrounds reviewed each slide. The hot spot method was employed at 20x power to identify the 3 spots in tumor stroma that stained most heavily. The number of CD206+ cells in each of 3 hot spots was counted, and the mean number of CD206+ cells per hot spot reported by two independent pathologists was averaged for analysis.

Results

65 patients met inclusion criteria, of these 31 had a recurrence within 5 years of diagnosis. There was no correlation between likelihood of recurrence or overall survival and CD206 expression. In the 31 patients that had a recurrence, a high CD206 count of greater than or equal to 15 was associated with a shorter time to recurrence than a CD206 count of less than 15 (14.8 months vs. 22 months, respectively, p = 0.028). Mean age at diagnosis in the recurrence group was 59.6 vs. 60 years, and 15 (60%) vs. 2(33%) patients were ER positive in the low CD206 (<15) vs. high CD206 ( = >15) groups, respectively.

Conclusion

High expression of CD206 in the tumor stroma was associated with a shorter time to recurrence in patients with stage 3, HER-2 negative breast cancer; however, there were more ER negative tumors in the high CD 206 group. Our research supports in vitro data that high CD206 expression in macrophages may represent a more aggressive tumor phenotype. Future studies focusing on studying CD206 expression in HER-2 positive breast tumors along with histological stratification are needed to confirm this finding.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-06-11.

ROS-mediated apoptotic cell death in prostate cancer LNCaP cells induced by biosurfactant stabilized CdS quantum dots

Cadmium sulfide (CdS) quantum dots (QDs) have raised great attention because of their superior optical properties and wide utilization in biological and biomedical studies. However, little is known about the cell death mechanisms of CdS QDs in human cancer cells. This study was designed to investigate the possible mechanisms of apoptosis induced by biosurfactant stabilized CdS QDs (denoted as "bsCdS QDs") in human prostate cancer LNCaP cells. It was also noteworthy that apoptosis correlated with reactive oxygen species (ROS) production, mitochondrial damage, oxidative stress and chromatin condensation in a dose- and time-dependent manner. Results also showed involvement of caspases, Bcl-2 family proteins, heat shock protein 70, and a cell-cycle checkpoint protein p53 in apoptosis induction by bsCdS QDs in LNCaP cells. Moreover, pro-apoptotic protein Bax was upregulated and the anti-apoptotic proteins, survivin and NF-κB were downregulated in bsCdS QDs exposed cells. Protection of N-acetyl cysteine (NAC) against ROS clearly suggested the implication of ROS in hyper-activation of apoptosis and cell death. It is encouraging to conclude that biologically stabilized CdS QDs bear the potential of its applications in biomedicine, such as tumor therapy specifically by inducing caspase-dependent apoptotic cell death of human prostate cancer LNCaP cells.

Lagerstroemia speciosa fruit extract modulates quorum sensing-controlled virulence factor production and biofilm formation in Pseudomonas aeruginosa

Lagerstroemia speciosa (Lythraceae) is a south-east Asian tree more commonly known as 'Jarul'. Research on health benefits suggests that the L. speciosa plant contains phytomolecules that may have antioxidant, anti-diabetic and anti-obesity properties. However, antimicrobial activities have not been reported for this plant. The ability of L. speciosa fruit extract (LSFE) to antagonize cell-to-cell communication, expression of virulence genes and factors, and biofilm formation was evaluated in Pseudomonas aeruginosa strain PAO1. Our results suggested that LSFE caused downregulation of quorum sensing (QS)-related genes (las and rhl) and their respective signalling molecules, N-acylhomoserine lactones, without affecting the growth of P. aeruginosa PAO1. Significant inhibition of virulence factors: LasA protease, LasB elastase, and pyoverdin production, was also recorded. Application of LSFE to P. aeruginosa PAO1 biofilms increased bacterial susceptibility to tobramycin. These data suggest a possible role for quorum-quenching mechanisms unrelated to static or cidal effects, and also suggest that L. speciosa could serve as a cost-effective source in the development of new QS-based antibacterial drugs.

Dietary use and conservation concern of edible wetland plants at Indo-Burma hotspot: a case study from Northeast India

BACKGROUND

The wetlands of the North East India fall among the global hotspots of biodiversity. However, they have received very little attention with relation to their intrinsic values to human kind; therefore their conservation is hardly addressed. These wetlands are critical for the sustenance of the tribal communities.

METHODS

Field research was conducted during 2003 to 2006 in seven major wetlands of four districts of Manipur state, Northeast India (viz. Imphal-East, Imphal-West, Thoubal, and Bishnupur). A total of 224 wetland-plant-collectors were interviewed for the use and economics of species using semi-structured questionnaires and interview schedules. Imphal, Bishenpur and Thoubal markets were investigated in detail for influx and consumption pattern of these plants. The collectors were also inquired for medicinal use of wetland species. Nutritive values of 21 species were analyzed in laboratory. The vouchers were collected for all the species and deposited in the CSIR-NEIST (Formerly Regional Research Laboratory), Substation, Lamphelpat, Imphal, Manipur, India.

RESULTS

We recorded 51 edible wetland species used by indigenous people for food and medicinal purposes. Thirty eight species had high medicinal values and used in the traditional system to treat over 22 diseases. At least 27 species were traded in three markets studied (i.e. Imphal, Thoubal and Bishenpur), involving an annual turnover of 113 tons of wetland edible plants and a gross revenue of Rs. 907, 770/- (US$1 = Rs. 45/-). The Imphal market alone supplies 60% of the total business. Eighty per cent of the above mentioned species are very often used by the community. The community has a general opinion that the availability of 45% species has depleted in recent times, 15 species need consideration for conservation while another 7 species deserved immediate protection measures. The nutrient analysis showed that these species contribute to the dietary balance of tribal communities.

CONCLUSIONS

Considering the importance of wild wetland plants in local sustenance, it is suggested to protect their habitats, develop domestication protocols of selected species, and build programs for the long-term management of wetland areas by involving local people. Some medicinal plants may also be used to develop into modern medicines.

Atmospheric carbon tetrachloride: another man-made pollutant

On the basis of an analysis of historic worldwide emissions and removal mechanisms for carbon tetrachloride, a possible precursor for stratospheric ozone destruction, it has been demonstrated that the present atmospheric loading and distribution of carbon tetrachloride is primarily attributable to man-made emissions and no natural sources need be invoked to explain its presence in the atmosphere.

Anti-tuberculosis activity of selected medicinal plants against multi-drug resistant Mycobacterium tuberculosis isolates

BACKGROUND & OBJECTIVES

Emergence of multi-drug resistant (MDR) and extensively-drug resistant (XDR) strains of Mycobacterium tuberculosis has further complicated the problem of tuberculosis (TB) control. Medicinal plants offer a hope for developing alternate medicines for the treatment of TB. The present study was done to evaluate in vitro anti-tubercular activity of five medicinal plants viz., Acalypha indica, Adhatoda vasica, Allium cepa, Allium sativum and Aloe vera.

METHODS

Aqueous extracts of leaves of A. indica, A. vasica, bulbs of A. cepa, cloves of A. sativum and pure gel of A. vera leaves, were tested in vitro for their activity against two MDR isolates (DKU-156 and JAL-1236), reference susceptible strain M. tuberculosis H37Rv as well as rapid grower mycobacterial pathogen M. fortuitum (TMC-1529) using Lowenstein Jensen (L-J) medium and colorimetric BacT/ ALERT 3D system. Activity in L-J medium was evaluated by percentage inhibition which was calculated by mean reduction in number of colonies on extract containing as compared to extract free controls.

RESULTS

Extracts of all the five plants A. indica, A. vasica, A. cepa, A. sativum and A. vera exhibited anti-tuberculosis activity in L-J medium, the proportion of inhibition of these plants extract in respect mentioned above is 95, 32, 37, 72, 32 per cent, respectively for MDR isolate DKU-156 and 68, 86, 79, 72, 85 per cent, respectively for another MDR isolate JAL-1236, while for sensitive M. tuberculosis H37Rv, inhibition was found to be 68, 70, 35, 63 and 41 per cent, at 4 per cent v/v concentration in L-J medium. There was no inhibition against rapid grower M. fortuitum (TMC-1529). In BacT/ALERT also, extracts of these plants showed significant inhibition against M. tuberculosis.

INTERPRETATION & CONCLUSION

Our findings showed that all these plants exhibited activity against MDR isolates of M. tuberculosis. While the anti-TB activity of A. vera, A. vasica and A. sativum against MDR isolates confirm earlier results, activity of the extracts of A. indica and A. cepa is reported for the first time. Further studies aimed at isolation and identification of active substances from the extracts which exhibited promising activities, need to be carried out.

Simultaneous determination of beryllium and aluminium in mixtures using derivative spectrophotometry

The spectrophotometric determination of beryllium and aluminium with 5,8-dihydroxy-1,4-naphthoquinone in the presence of a non-ionic surfactant is reported. Absorption maxima, molar absorptivity and Sandell's Sensitivity of 1:2 (M:L) beryllium and aluminium complexes are, 585 nm and 598 nm, 1.63 x 10(4) l.mole(-1).cm(-1) and 2.04 x 10(4) l.mole(-1).cm(-1), and 0.55 ng/cm(2) and 1.32 ng/cm(2) respectively. Beer's law is obeyed between 7.20-3.96 x 10(2) ng/ml beryllium and 1.08 x 10(1)-1.08 x 10(3) ng/ml aluminium. A method for simultaneous determination of beryllium and aluminium in their mixture using derivative spectra is described. The range 3.6 x 10(1)-3.6 x 10(2) ng/ml beryllium could be determined in the presence of 1.08 x 10(2)-1.08 x 10(3) ng/ml aluminium, and vice versa.

Oxidative DNA damage protective activity, antioxidant and anti-quorum sensing potentials of Moringa oleifera

The aqueous extract of leaf (LE), fruit (FE) and seed (SE) of Moringa oleifera was assessed to examine the ability to inhibit the oxidative DNA damage, antioxidant and anti-quorum sensing (QS) potentials. It was found that these extracts could significantly inhibit the OH-dependent damage of pUC18 plasmid DNA and also inhibit synergistically with trolox, with an activity sequence of LE > FE > SE. HPLC and MS/MS analysis was carried out, which showed the presence of gallic acid, chlorogenic acid, ellagic acid, ferulic acid, kaempferol, quercetin and vanillin. The LE was with comparatively higher total phenolics content (105.04 mg gallic acid equivalents (GAE)/g), total flavonoids content (31.28 mg quercetin equivalents (QE)/g), and ascorbic acid content (106.95 mg/100 g) and showed better antioxidant activity (85.77%), anti-radical power (74.3), reducing power (1.1 ascorbic acid equivalents (ASE)/ml), inhibition of lipid peroxidation, protein oxidation, OH-induced deoxyribose degradation, and scavenging power of superoxide anion and nitric oxide radicals than did the FE, SE and standard alpha-tocopherol. Eventually, LE and FE were found to inhibit violacein production, a QS-regulated behavior in Chromobacterium violaceum 12472.

Polyphenolics from various extracts/fractions of red onion (Allium cepa) peel with potent antioxidant and antimutagenic activities

In order to determine antioxidant activity, the five extracts/fractions of red onion peel were studied for their total content of phenolics (TPC), flavonoids (TFC), antioxidant activity (AOA), free radical scavenging activity (FRSA), assayed by DPPH radical in the terms of anti-radical power (ARP) and reducing power (RP), expressed as ascorbic acid equivalents (ASE)/ml. High TPC (384.7 +/- 5.0 mg GAE/g), TFC (165.2+/- 3.2 mg QE/g), AOA (97.4 +/- 7.6%), ARP (75.3 +/-4.5) and RP (1.6 +/-0.3 ASE/ml) were found for the ethyl acetate (EA) fraction. EA fraction had markedly higher antioxidant capacity than butylated hydroxytoluene (BHT) in preventive or scavenging capacities against FeCl3-induced lipid peroxidation, protein fragmentation, hydroxyl (site-specific and non-site-specific), superoxide anion and nitric oxide radicals. EA fraction also showed dose dependent antimutagenic activity by following the inhibition of tobacco-induced mutagenicity in Salmonella typhimurium strains (TA102) and hydroxyl radical-induced nicking in plasmid pUC18 DNA. HPLC and MS/MS analysis showed the presence of ferulic, gallic, protocatechuic acids, quercetin and kaempferol. The large amount of polyphenols contained in EA fraction may cause its strong antioxidant and antimutagenic properties. This information shows that EA fraction of red onion peel can be used as natural antioxidant in nutraceutical preparations.

Antiangiogenic and proapoptotic activities of allyl isothiocyanate inhibit ascites tumor growth in vivo

The authors investigate the antiangiogenic and proapoptotic effects of mustard essential oil containing allyl isothiocyanate (AITC) and explore its mechanism of action on Ehrlich ascites tumor (EAT) cells. Swiss albino mice transplanted with EAT cells were used to study the effect of AITC. AITC was effective at a concentration of 10 mum as demonstrated by the inhibition of proliferation of EAT cells when compared with the normal HEK293 cells. It significantly reduced ascites secretion and tumor cell proliferation by about 80% and inhibited vascular endothelial growth factor expression in tumor-bearing mice in vivo. It also reduced vessel sprouting and exhibited potent antiangiogenic activity in the chorioallantoic membrane and cornea of the rat. AITC arrested the growth of EAT cells by inducing apoptosis and effectively arrested cell cycle progression at the G1 phase. The results clearly suggest that AITC inhibits tumor growth by both antiangiogenic and proapoptotic mechanisms.

Antioxidant and anti-quorum sensing activities of green pod of Acacia nilotica L

The antioxidant and anti-quorum sensing activities of eight extracts were studied in green pods of Acacia nilotica. The specific phenolic compositions and their quantifications were performed by HPLC and MS/MS, which showed that the HEF (pH 4) was higher in gallic acid, ellagic acid, epicatechin, rutin, and GTs. In order to find antioxidant potential of various extracts, their activities were studied for TPC, AOA, FRSA, RP, inhibition of LPO, FIC activity, HO* and O(2)(-) scavenging activities. Among them HEF (pH 4) has shown potent antioxidant activity. HEF (pH 4) was also found effective in protecting plasmid DNA and HAS protein oxidation induced by HO*. Pre-treatment of HEF (pH 4) at 75 and 150 mg/kg body weight for 6 days caused a significant increase in the levels of CAT and SOD and decrease in the level of MDA content in liver, lungs, kidneys and blood when compared to CCl(4)-intoxicated rats. Eventually, the extracts were also screened for anti-QS activity. Of these extracts two showed QS inhibition: HEF (pH 4) and HCE. The results obtained strongly indicate that green pod of A. nilotica are important source of natural antioxidants.

Long term follow-up results of 1 year MDT in MB leprosy patients treated with standard MDT + once a month Minocycline and Ofloxacin

BACKGROUND

This study was initiated in consultation with the National Leprosy Eradication Programme (NLEP) in mid nineties to try new treatment regimens for leprosy which were more robust in terms of control of reactions, long term relapses, operationally easier to undertake and feasible in field conditions. It was also envisaged to see if the addition of newer bactericidal drugs would be beneficial.

OBJECTIVES

(i) To test the feasibility, safety and response of the patients to the new regimen. (ii) To observe the incidence of reactions during and after stoppage of therapy, for a period of 8-10 years after release from treatment.

MATERIALS AND METHODS

A total of one hundred skin smear positive MB patients (15 LL, 35 BL and 50 BB) patients were included in this study. All the patients received the standard MDT + once a month supervised 100 mg of Minocycline and 400 mg of Ofloxacin for 12 months during the treatment phase. Thereafter, the treatment was stopped in all the patients which were followed-up on placebo (B complex tablets). Of these, 70 patients completed the treatment schedule of one year therapy and the post treatment follow-up of 9 to 10 years.

RESULTS

All the patients tolerated the drugs well. The clinical response of the patients to the treatment was very good of which 32.85% of cases had history of reactions before starting treatment. During treatment, the incidence of reactions increased marginally to 38.5%, but these were easily controlled with concurrent administration of steroids. After completion of treatment the incidence was much less i.e. 10% and 3% after 1 and 2 years of post treatment follow-up respectively. The overall relapse rate is 5.7% (4/70) with an incidence density of 0.05/100 patient years. Relapses were confirmed by clinical, bacteriological, molecular biological (rRNA probes and 36 kD targeting PCR) as well as ATP bioluminescence. The relapsed patients presented with the appearance of new lesions, slit-skin smears were again found to become positive after becoming negative. Three of the four cases who relapsed had the initial mean BI of 2 to 2.9+ whereas one had the initial mean BI of 1.5+. Also, 2 of the 4 relapsed patients had positive PCR signals at the time of stoppage of treatment.

CONCLUSION

The addition of Minocycline and Ofloxacin to the standard FDT has been observed to be a well tolerated. Overall as of now, the incidence of reactions observed with the newer treatment regimen is found to be significantly lower than that of 2 years fixed duration MB-MDT. The efficacy of this regimen regarding bacteriological clearance and relapse rates could not be compared due to non-availability of the results of experience with standard 1 year MDT regimen. However, this regimen appears to be operationally feasible and safe for the users.

Isolation of Mycobacterium bovis & M. tuberculosis from cattle of some farms in north India--possible relevance in human health

BACKGROUND & OBJECTIVE

Infection due to Mycobacterium bovis typically occurs in cattle and animals transmit infection to each other. The choice of appropriate clinical specimen is very important for isolation of M. bovis and M. tuberculosis from cattle. The present study reports the isolation of M. tuberculosis and M. bovis from different types of specimens from cattle suspected to be suffering from tuberculosis in certain organized cattle farms in north India.

METHODS

A total of 768 specimens (heparinized or EDTA containing blood (162), fine needle aspirates from prescapular lymph gland (PSLG,160), milk (154), pharyngeal swab (PhS, 98), rectal pinch (RP, 97) and faecal sample (97) from 161 cattle of organized cattle farms in north India suspected to be suffering from tuberculosis were analyzed. After decontamination by modified Petroff's method isolation of M.tuberculosis complex was done on Lowenstein-Jensen medium (with and without pyruvate). The culture isolates were identified as M. tuberculosis and M. bovis on the basis of biochemical tests.

RESULTS

A total of 54 M. tuberculosis complex isolates were obtained, of them 40 were identified as M.bovis and 14 as M. tuberculosis. M.bovis were isolated from 12 of 38 animals in group A (Tuberculin +ve with signs of tuberculosis), 7 of 37 animals in group B (Tuberculin +ve and apparently healthy), 9 of 21 group C animals in (Tuberculin -ve with clinical signs of tuberculosis), 4 of 26 animals in group D (Tuberculin -ve and apparently healthy), 4 of 27 group E animals (having non-mycobacterial infection) and 4 of 12 animals in group F (having clinical signs such as debilitated condition, cough, decreasing milk production, etc). Maximum number of M. bovis (19/40, 47.5%) and M. tuberculosis (5/14, 35.7%) isolates were grown from prescapular lymph gland biopsy (PSLG) followed by blood from which 9/40 (22.5%) M. bovis and 4/14 (28.5%) M. tuberculosis were isolated. M. bovis [6/40(15%)] and M. tuberculosis [4/14(28.5%)] were also isolated from milk. Only 3/40 (7.5%) isolates of M.bovis could be isolated from 97 rectal pinch followed by 98 pharyngeal swab 2/40 (5%) and 97 fecal samples 1/40 (2.5%) while 1/14 (7.1%) M.tuberculosis isolates were obtained from pharyngeal swab.

INTERPRETATION & CONCLUSION

Among the samples analyzed, PSLG was found to be most suitable specimen for isolation of M. tuberculosis complex from cattle and is thus of diagnostic importance. M. bovis in milk indicates the need to investigate the transmission to human in such settings. Isolation of M. bovis and/or M. tuberculosis from apparently healthy cattle indicates sub-clinical infection in the herd. Further, isolation of a significant number of M. tuberculosis from cattle suggests possible human-to-cattle transmission which need to be confirmed by prospective studies including tools like DNA fingerprinting.

Molecular typing of Mycobacterium tuberculosis isolates from different parts of India based on IS6110 element polymorphism using RFLP analysis

BACKGROUND & OBJECTIVE

IS 6110 based typing remains the internationally accepted standard and continues to provide new insights into the epidemiology of Mycobacterium tuberculosis. The aim of the study was to characterize M. tuberculosis isolates obtained from different parts of India based on IS6110 element polymorphism using restriction fragment length polymorphism (RFLP) analysis.

METHODS

RFLP was analyzed among 308 isolates of M. tuberculosis deposited in the Mycobacterial Repository Centre, Agra, from different parts of India. DNAs isolated from these strains were restricted with Pvu II, transferred on to nylon membrane and hybridized with a PCR amplified DIG-labeled 245 bp IS6110 probe.

RESULTS

Based on the copy number, M. tuberculosis isolates were classified into four groups, (i) lacking IS6110 element; (ii) low copy number (1-2); (iii) intermediate copy number (3-5); and (iv) high copy number (6-19). Copy number higher than 19 however was not observed in any of the isolates studied. At the national level, 56 per cent of the isolates showed high copy number of IS6110, 13 per cent showed intermediate copy number, 20 per cent showed low copy number, whereas 11 per cent isolates lacked IS6110 element. At the regional level, there was not much difference in the RFLP profiles of isolates (IS6110 copy numbers/patterns) from different parts of the country.

INTERPRETATION & CONCLUSION

IS6110 DNA based fingerprinting could be a potentially useful tool for investigating the epidemiology of tuberculosis in India.

Effect of substrates on growth and shelf life of Trichoderma harzianum and its use in biocontrol of diseases

A study on the effect of different agrowastes on the population density and shelf life of Trichoderma harzianum indicated that all the substrates showed effective propagation of T. harzianum; however, the population count after 30 days was maximum in used tea leaves (8 x 10(8) cfu/g) and shelf life was found to be maximum (2.9 x 10(5) cfu/g after 210 days) in wheat bran-sawdust. The application of these formulations on chickpea and groundnut plants significantly reduced the percent mortality due to chickpea wilt complex and groundnut collar rot disease, respectively.

Diagnostic value of Elisa serological tests in childhood tuberculosis

Two separate studies (study I and study II) were conducted to evaluate the efficacy of ELISA serological test for the detection of IgG antibodies against specific glycolipid antigen (PGLTb1) and ESAT 6 antigen of Mycobacterium tuberculosis, respectively. These results were compared with bacteriological tests [Ziehl Neelson (ZN) staining for acid-fast bacilli and culture on Lowenstein Jensen (LJ) medium] and polymerase chain reaction (PCR) targeting IS6110 sequence. Both studies were carried out on children with pulmonary, central nervous system, lymph node, and gastrointestinal tuberculosis along with matching controls (65 cases and 27 controls for study I and 83 cases and 22 controls for study II). Informed consents of their parents or guardians were taken. They were subjected to clinical examination, relevant laboratory investigations, tuberculin test and chest radiograph. Relevant body fluids were subjected to bacteriological tests and PCR. Sera samples were analyzed for antibodies against PGLTbl and ESAT 6 antigen in study I and study II, respectively. ELISA tests showed a significantly higher sensitivity (49% study I; 53%, study II) as compared with LJ medium culture method (15.4%, study I; 28.9% study II) and ZN staining (27.7%, study I; 20.5%, study II) in all patients (p < 0.05). The results were comparable with PCR (40%, study I; 42.2% study II). Specificity of ELISA test was 100% in all the patients except in those with pulmonary disease (92.8%, study I; 84.8%, study II). In view of the convenience, low cost and comparable sensitivity with PCR, these ELISA tests have a promising future in the diagnosis of childhood tuberculosis.

A Yellow Mosaic Disease of Soybean in Northern India is Caused by Cotton leaf curl Kokhran virus

Soybean, Glycine max (L.) Merr., is a protein- and oil-rich crop cultivated in India and abroad. A yellow mosaic disease was observed on soybean with 80 to 90% disease incidence during August 2005 at fields of the National Botanical Research Institute, Lucknow, in northern India. Soybean plants were found to be infested with whiteflies (Bemisia tabaci) suggesting begomovirus etiology. The disease agent was transmitted experimentally by whiteflies, and symptoms developed after 23 days. Total DNA was isolated from 51 leaf samples collected from 42 symptomatic and 9 asymptomatic plants. Polymerase chain reaction was performed using begomovirus coat protein-specific primers 5'-ATGGCGAA GCGACCAG-3' and 5'-TTAATTTGTGACCGAATCAT-3' (AM180920/ AM180921). An amplicon of the expected size (~800 bp) was obtained in all 42 symptomatic leaves but not from any of the nine asymptomatic leaf samples. The amplicon was cloned, and the identical sequence of three clones was submitted to GenBank (Accession No. DQ343283). BLAST search of nucleotide sequences revealed 95% identity with Cotton leaf curl Kokhran virus (CLCKV) (GenBank Accession Nos. AJ002449, AJ002448, AJ496286, and AY456683) and 57% identity with Mungbean yellow mosaic India virus (MYMIV-Sb, GenBank Accession No. AY049772). Results indicated that the virus associated with yellow mosaic disease of soybean is an isolate of CLCKV rather than MYMIV-Sb (1) reported earlier on soybean from northern India. To our knowledge, this is the first report of soybean as a new host of Cotton leaf curl Kokhran virus. Reference: (1) K. S. Usharani et al. Curr. Sci. 86:845, 2004.

Detection of Mycobacterium leprae DNA from soil samples by PCR targeting RLEP sequences

Despite near elimination of leprosy as a public health problem, several problems in leprosy still remain. These include early detection, determining efficacy of the treatment and differentiating relapses from re-infection. These aspects have important impact on the patients undergoing treatment and also have a bearing on understanding transmission dynamics in the community. While early diagnosis and management do not need major technological inputs, various reports have suggested that M. leprae is found in the environment and may have a role in continued transmission of disease. In earlier studies from other parts of world the presence of M. leprae DNA in the environment has been investigated both by microbiological and molecular studies. In the present study, an attempt was made to extract M. leprae DNA from soil samples, which were collected from eighteen different locations including 3 from our Institute area and 15 from different villages of Ghatampur area. We optimized a protocol for the extraction of DNA and amplified a fragment of M. leprae using specific primers targeting RLEP sequences. It was found that 33.3% of these soil samples collected from areas inhabited by leprosy cases gave positive result for M. leprae specific DNA. The utility of this method needs to be explored on a larger scale to establish the presence of M.leprae in the environment, and its role in the spread of the disease.

Simultaneous use of two PCR systems targeting IS6110 and MPB64 for confirmation of diagnosis of tuberculous lymphadenitis

PCR has emerged as a powerful technique for detection of various pathogens including Mycobacterium tuberculosis. In present study, eighty one samples of lymph node biopsies from clinically suspected cases of tuberculous lymphadenitis were examined for AFB, culture on Löwenstein Jensen medium and simultaneous use of two PCRs targeting IS6110 and MPB64. Positivity with M. tuberculosis culture and AFB was 13.6% and 28.4% respectively. All samples culture positive for nontuberculous mycobacteria were negative by both PCR systems. Higher proportion of positive results were observed with PCR targeting IS6110 by which 56 of 81 (69.1%) samples showed positive results as compared to PCR targeting MPB64 by which 39 of 81 (48.2 %) samples showed positive results. When combined, 63 out of 81 (77.8%) samples were detected positive for M. tuberculosis DNA. However, 7/81 (8.6 %) samples remained negative by IS6110 but positive by MPB64 method. Thus our data suggest that the use of one additional PCR (other than IS6110 system) can reduce false negativity of PCR results in the samples harboring zero copy of IS6110 element which is known to exist in Indian population.

Detection of M. leprae by reverse transcription- PCR in biopsy specimens from leprosy cases: a preliminary study

A reverse transcription (RT)-PCR assay targeting 16S rRNA of Mycobacterium leprae has been used to detect M.leprae specific nucleic acids. This study has been initiated to gain experience about detection of RNA from seven biopsy specimens by RT-PCR assay using species- specific primers described earlier. These biopsy specimens were from clinically confirmed and untreated leprosy cases belonging to BB and BL types. The earlier reported method was established in our laboratory. 171 bp fragment by RT-PCR was amplified from 4/7 cases. The positives results by RT-PCR were from the biopsies from fresh or short term treated cases whereas negative results were from specimens from long term treated cases showing clinical features of relapse. DNA targeting PCR (36 KDa) showed positivity in both groups. These results suggest that RT-PCR positivity possibly reflect the presence of viable organisms. Thus as earlier predicted RT-PCR assay may be useful for viability determinations for assessing the response to chemotherapy as well as presence of persisters in relapse cases.

Persister studies in leprosy patients after multi-drug treatment

Cutaneous biopsies were collected from leprosy patients who attended the out-patient department of the Institute for treatment at different intervals, i.e., 12 months, 18 months, 24 months, 36 months, and more after beginning the multi-drug treatment therapy (M.D.T.). The patients belonged to the two drug regimens; (i) standard multibacillary (MB) M.D.T. after 12, 24, and 36 months; or (ii) standard M.D.T. + Minocycline 100 mg once a month (supervised) + Ofloxacin 400 mg once a month supervised for 12 months Biopsies were processed for mouse footpad inoculation and for estimating ATP levels by bioluminescence assay as per established methods. Viable bacilli were observed in 23.5% up to 1 year, 7.1% at 2 years, and in 3.84% at 3 years of M.D.T. by MFP and 29.4%, 10.7%, and 3.84% by ATP assay in the M.D.T. group at the same time period, respectively, but not in M.D.T. + Minocycline + Ofloxacin group after one year. The overall percentage of persisters was 5.55% by MFP and 7.14% by ATP assay up to 3 years of treatment.

Correlation of mutations detected by INNO-LiPA with levels of rifampicin resistance in Mycobacterium tuberculosis

BACKGROUND & OBJECTIVES

Due to emergence of drug resistance in Mycobacterium tuberculosis, there is a need to have accurate and rapid methods for detection of drug resistance to important drugs like rifampicin. The present study was aimed at evaluation of a commercially available INNO-LiPA assay, for the detection of mutation in rpoB gene region of M. tuberculosis and correlate these mutations with levels of rifampicin resistance for assessing their clinical relevance.

METHODS

Fifty five well-characterized isolates of M. tuberculosis deposited from various regions of India in Mycobacterial Repository Centre at the CJILOMD, Agra were subjected to susceptibility testing for rifampicin at various concentrations of drug viz., 10, 40, 64, 128 microg/ml on Lowenstein- Jensen (LJ) medium. rpoB gene fragment (260 bp) was amplified using Rif-TB amplification kit and after hybridization, detection was done by using INNO-LiPA Rif TB kit.

RESULTS

The rpoB gene could be amplified from DNA extracted from all the 55 culture isolates and showed clear hybridization pattern with M. tuberculosis complex specific probes on LiPA strips. Mutations detected were correlated with degree of rifampicin resistance. All the sensitive isolates (identified by MIC) were identified as rifampicin sensitive (100%) by INNO-LiPA as they exhibit positive for wild type 'S' probes and negative for 'R' probes. Two of the 5 isolates, resistant at 10 microg/ml and 40 microg/ml had either D516V, H526Y mutations or unknown mutations. Thirty (85.71%) isolates resistant at clinically relevant levels (64,128microg/ml) exhibited double, triple or more 'R' type mutations (R(2(D516V)), R(4a(H526Y)), R(4b(H526D)), R(5(S531L))) as well as unknown mutations present at 'S' probes region whereas remaining isolates did not show any mutation by this method. This method could identify with definitiveness 60 per cent ( 21/35) isolates as rifampicin resistant as mutations observed in others were also present in isolates with low levels of resistance.

INTERPRETATION & CONCLUSION

The results indicate that INNO-LiPA Rif TB test is a rapid and easy to use method for detection of mutations associated with rifampicin resistance in M. tuberculosis. However, as some of these mutations are also present in isolates with low degree of resistance which are still microbiologically sensitive to rifampicin, there is a need to improve this assay by exclusion of some of the current probes and inclusion of more probes.

Survival of the rhizosphere-competent biocontrol strain Pseudomonas fluorescens NBRI2650 in the soil and phytosphere

Pseudomonas fluorescens NBRI2650 was isolated after screening 360 bacterial strains from the rhizosphere of chickpea (Cicer arietinum L.) grown in fungal-disease-suppressive field soil. The strain was selected because of its high rhizosphere competence and ability to inhibit the growth of Fusarium oxysporum f.sp. ciceri, Rhizoctonia bataticola, and Pythium sp. under in vitro conditions. Survival and colonization of NBRI2650 in the phytosphere of chickpea, cotton (Gossypium hirsutum L.), cucumber (Cucumis sativus L.), and tomato (Lycopersicon seculentum Mill.) were monitored using a chromosomally located rifampicin-marked mutant P. fluorescens NBRI2650R. The strain showed variable ability to invade and survive in the phytosphere of different plants. Chickpea was used as a tester plant for further work, as it was not invaded by NBRI2650R. The interaction between NBRI2650R and F oxysporum fsp. ciceri was studied by both light microscopy and scanning electron microscopy. The lysis of the fungal cell wall by NBRI2650R was clearly demonstrated. Treatment of the chickpea seeds with NBRI2650R in prerelease experiments in the greenhouse using disease-conducive field soils from Jhansi and Kanpur resulted in increased plant growth and did not result in any perturbation of the indigenous microbial community that inhabited the rhizosphere of chickpea compared with nonbacterized seeds. Direct fermentation of diluted NBRI2650R on vermiculite without the need of expensive fermentors offers a reliable process for manufacturing bacterial inoculants in developing countries. Under field conditions, the horizontal and vertical movement of NBRI2650R was restricted to 30 and 60 cm, respectively, and the strain could not survive in the field during the 7 months before the chickpea could be planted for next cropping season. Field trials conducted at Jhansi, Kanpur, and Pantnagar resulted in higher grain yield increase in the bacteria-treated seed compared with the nonbacterized control. Seed and furrow treatment of the two chickpeas ('Radhey' and 'H-208') at Pantnagar resulted in significantly (P = 0.05) greater seedling mortality in nonbacterized seedlings compared with bacterized ones. The seed dry weight and yield for each variety were also significantly higher in bacterized seedlings than in nonbacterized ones. The population of NBRI2650R persisted throughout the growing season of chickpea in the range of 5.4-6.4 log10 CFU/g root.

A preliminary report on characterization and identification of non tuberculous mycobacteria (NTM) on the basis of biochemical tests and protein / isoenzyme electrophoretic patterns

PURPOSE

To assess the usefulness of protein electrophorograms and protein zymodemes in the identification and characterization of non tuberculous mycobacteria (NTM).

METHODS

Cell free extracts (CFEs) from 22 mycobacterial isolates belonging to slow growing and other clinically relevant species were included in the study. The strains isolated from the environment were identified on the basis of their standard biochemical tests; pigmentation and growth characters. The CFEs were electrophoresed and stained for proteins and esterases.

RESULTS

Most of the isolates identified on the basis of biochemical tests exhibited characteristic protein and esterase pattern for M. scrofulaceum, M. avium and M. xenopi. Others showed variations in their proteins and esterase pattern though they were identified as M. scrofulaceum, M. avium and M. xenopi.

CONCLUSIONS

Based on these studies it appears that because of variability in the protein and isoenzyme patterns of NTM, it may be advisable to use them along with biochemical tests and other tests for identifying and characterizing the different mycobacterial species belonging to slow growers.

Drug susceptibility profiles of Mycobacterium tuberculosis isolates at Jaipur

PURPOSE

To find prevalence of drug resistance in Mycobacterium tuberculosis isolated from patients attending SMS Medical College, Jaipur during 1997-99.

METHODS

Sputum samples from 164 patients with pulmonary tuberculosis were processed and cultured on Lowenstein Jensen medium and M. tuberculosis isolates were tested for drug sensitivity.

RESULTS

M. tuberculosis was isolated in 122/164 (74.3%) samples and comprised 97.6% (122/125) of mycobacterial isolates. There were only three isolates of nontuberculous mycobacteria -one each of M. kansasii, M. avium and M. fortutium. Primary drug resistance in M. tuberculosis was estimated to be 3/44 (6.8%) to rifampicin, 6/44 (13.6%) to isoniazid and 2 strains (4.5%) were multi drug resistant i.e. resistant to both rifampicin and isoniazid. Among the isolates from cases with previous history of treatment of varying duration (acquired drug resistance) resistance to rifampicin was estimated to be 28.2% and for isoniazid to be 39.7%. 24.3% strains of these drug resistant isolates were multi drug resistant.

CONCLUSIONS

While this information may not reflect true prevalence of drug resistance in the region this may help in further planning long term surveillance studies to know the trend of drug resistance in this area.

Rapid discrimination of Indian isolates of M. tuberculosis by random amplified polymorphic DNA (RAPD) analysis - a preliminary report

PURPOSE

Due to relatively complex nature of molecular typing systems for M. tuberculosis as well as lack of applicability of some of the probes, there is a need for alternate procedures for molecular epidemiology. In this study the usefulness of RAPD analysis for typing of Indian strains of M.tuberculosis was investigated.

METHODS

One hundred and three coded isolates from different parts of the country were analysed by Random amplified polymorphic DNA (RAPD) technique. Purified and amplified DNA from cultures were analysed by ethidium bromide staining after electrophoresis. The bands were confirmed by densitometry and the patterns were analysed by hierarchical cluster analysis.

RESULTS

The patterns elicited by the analysis appeared to be quite discriminatory and characteristic.

CONCLUSIONS

Clustering observed among isolates attending the same hospital indicates future application potential of RAPD analysis for molecular epidemiology of tuberculosis in India.

Analysis of quantitative relationship between viability determination in leprosy by MFP, ATP bioluminescence and gene amplification assay

Two hundred twenty-one untreated, borderline lepromatous/lepromatous (BL/LL) leprosy patients have been investigated for viability by the mouse foot pad method (MFP), adenosine triphosphate (ATP) and polymerase chain reaction (PCR). The biopsies were collected at the beginning of and 12/24 months after treatment. The patient group was treated with a) immunotherapy (BCG/Mw) + MDT; b) MDT + pyrazinamide; c) control MDT; d) MDT + minocycline 100 mg once a month supervised + ofloxacin 400 mg once a month supervised. Biopsies were divided in three parts for use in the mouse foot pad, molecular and ATP investigations. In untreated and treated patients (at 12 and 24 months), there was a general agreement among all three techniques, and PCR and ATP showed higher positivity as compared to MFP. Further, there was good correlation among the viable biomass estimated by bacillary ATP levels, PCR assay and growth in mouse foot pads. The positivity was observed by MFP as well as PCR assay (18-kDa and 36-kDa) from all of the specimens when the ATP content was more than 3.6 pg/million. When the ATP content was below 3.5 pg/million, the positive takes in MFP decreased but the PCR positivity correlated with ATP bioluminescence up to 0.04 pg/million. When the ATP content was even lower, the uptake in the MFP was possibly a matter of chance, while PCR positivity was observed in 96% of the cases. For specimens with undetectable ATP, positivity was seen in 1% of the cases, showing the inability of ATP bioluminescence method to detect low background due to host ATP. PCR signals in some cases could be due to the higher sensitivity of the method or persistence of DNA after bacterial death in some cases. On the whole, the PCR methods even though targeting DNA have shown good correlations with biomass which confirm their usefulness in monitoring therapeutic responses in leprosy.

Glutathione peroxidase-like antioxidant activity of diaryl diselenides: a mechanistic study

The synthesis, structure, and thiol peroxidase-like antioxidant activities of several diaryl diselenides having intramolecularly coordinating amino groups are described. The diselenides derived from enantiomerically pure R-(+)- and S-(-)-N,N-dimethyl(1-ferrocenylethyl)amine show excellent peroxidase activity. To investigate the mechanistic role of various organoselenium intermediates, a detailed in situ characterization of the intermediates has been carried out by (77)Se NMR spectroscopy. While most of the diselenides exert their peroxidase activity via selenol, selenenic acid, and selenenyl sulfide intermediates, the differences in the relative activities of the diselenides are due to the varying degree of intramolecular Se.N interaction. The diselenides having strong Se.N interactions are found to be inactive due to the ability of their selenenyl sulfide derivatives to enhance the reverse GPx cycle (RSeSR + H(2)O(2) = RSeOH). In these cases, the nucleophilic attack of thiol takes place preferentially at selenium rather than sulfur and this reduces the formation of selenol by terminating the forward reaction. On the other hand, the diselenides having weak Se.N interactions are found to be more active due to the fast reaction of the selenenyl sulfide derivatives with thiol to produce diphenyl disulfide and the expected selenol (RSeSR + PhSH = PhSSPh + RSeH). The unsubstituted diaryl diselenides are found to be less active due to the slow reactions of these diselenides with thiol and hydrogen peroxide and also due to the instability of the intermediates. The catalytic cycles of 18 and 19 strongly resemble the mechanism by which the natural enzyme, glutathione peroxidase, catalyzes the reduction of hydroperoxides.

Effect of treatment on PCR positivity in multibacillary leprosy patients treated with conventional and newer drugs ofloxacin and minocycline

In order to develop objective criteria to monitor trends of therapeutic responses positivity of PCR signals and ATP assay methods has been compared in multibacillary (MB) leprosy patients. Biopsies from lesions of 95 BL/LL patients before and after one year of treatment with a new drug regimen comprising of conventional and newer drugs ofloxacin and minocycline have been studied. These biopsies were processed for bacillary ATP assay and PCR positivity for a 36 kDa gene target by earlier published methods. In the untreated patients bacillary ATP levels were detectable in all specimens and ranged from 0.02 to more than 36 pg/millions organisms. After one year of treatment ATP levels were not detectable in any of the 57 biopsies specimens available for analysis. However, PCR signals were detectable in 3 out of 57 biopsies. In two specimens signals were very weak detectable only by hybridization. It may be concluded that DNA based PCR assay may be useful in monitoring the trends of therapeutic responses in MB patients under treatment.

Assessment of viability by normal mouse foot-pad and bacillary ATP bioluminescence assay in multibacillary cases treated with an MDT regimen using conventional as well as newer drugs like minocycline and ofloxacin

The therapeutic effect of a drug regimen of conventional drugs as well as newer drugs like ofloxacin and minocycline in smear-positive multibacillary (MB) leprosy cases was assessed by mouse foot-pad and ATP bioluminiscence methods. Biopsies were taken before starting treatment and after one year of treatment. They were processed for viability assessment by normal mouse foot-pad inoculation and bacillary ATP assay techniques. The test regimen was quite effective in its anti-bacterial effect as it was found to result in loss of bacillary viability in all the cases, as assessed by both methods.

Chemotherapy trials in MB leprosy using conventional and newer drugs pefloxacin and minocycline

One hundred, untreated, smear positive BB, BL and LL patients were treated with a regimen comprising of once a month, supervised, 600 mg of Rifampicin+ 400 mg Ofloxacin + 100 mg of Minocycline in addition to self administered 100 mg dapsone and 50 mg of clofazimine daily for twelve months.The treatment was then stopped and patients were followed up on placebo. This study reports the preliminary results after 2.5 to 3.5 years of post treatment follow-up. The drugs were well tolerated, the clinical response to the treatment was very good, and there was no case of treatment failure. Bacteriologically 25 out of the total 70 patients available for follow- up were still positive at the end of one year of treatment. These patients continued to progress satisfactorily and four patients were still positive at the end of 2 years. No growth was observed in the normal mouse foot pad after one year of therapy. No bacillary ATP was detected in the biopsy tissues after one year. While no M. leprae specific rRNA was detectable in any of the specimens after one year of treatment, weak PCR signals were detectable in 3/57 specimens at that period. In the follow up available no patient has relapsed. The patients are being followed up on placebo and longer follow-up is required to draw firm conclusions.

Chemotherapy trial in paucibacillary leprosy using clofazimine

In a double blind study, 300 PB patients (smear negative, indeterminate, tuberculoid and borderline tuberculoid) were randomly allotted to two regimens, the control subjects (150 patients) receiving the standard WHO multidrug regimen of six doses of once a month rifampicin with daily dapsone therapy for six months, while the study group (150 patients) receiving 50 mg of clofazimine daily for six months in addition to the WHO regimen. After stoppage of therapy all the patients were followed up on placebo. The regimens were well tolerated. In 7.5% of patients on clofazimine containing regimen, the lesions showed persisting activity at the time of stoppage of therapy, compared with 16% on the control regimen. This activity subsided spontaneously, more rapidly, in the study group (80% compared with 30% in the control group) in six months. Two patients in the control group and one patient in the study group developed late reaction. There were no relapses in the study group, whereas, two patients have relapsed in the control group during a follow-up of 2.5 to 3.5 years.

Rapid detection of Mycobacterium bovis on its lipid profile by thin layer chromatography

Sixteen Mycobacterium bovis (M. bovis) strains isolated from bovine tissues and one standard reference strain of M. bovis AN5 alongwith other species of mycobacteria for comparison were investigated for the presence of phenolic glycolipid (PGL) and phthiocerol dimycocerosate (PDIM) for rapid identification of M. bovis by thin-layer chromatography (TLC). The study indicated presence of PGL with an Rf value of 0.75 in chloroform-methanol solvent in all 17 M. bovis strains. The dimycocerostate A corresponding to spot A was the major constituent among all the three spots in M. bovis strains. TLC appeared to be a promising alternative to conventional biochemical methods for identification of M. bovis taking into consideration both PGL and PDIM lipids.

Detection of viable organisms in leprosy patients treated with multidrug therapy

Cutaneous biopsies were collected from multibacillary leprosy patients who attended the out-patient department of Jalma Institute for treatment at different time intervals, i.e. 6 months, 12 months, 18 months, 24 months, 30 months, 36 months and 42 months after starting multidrug therapy (MDT) when they were still skin smear positive. Biopsies were processed for inoculation into mouse foot pad (MFP) and estimation of bacillary ATP levels by bioluminescent assay (ATP assay) by earlier established procedures. Viable bacilli were detectable after 1 year (25% cases by MFP and 31% cases by ATP assay), 2 years (8% cases by MFP and 12% cases by ATP assay) and 3 years (4% cases by both MFP and ATP assays). Overall, the percentage of the persisters was 10% by MFP and 13% by ATP assay. It would be important to carry out surveillance studies in larger number of BL/LL cases to know the trends and also the resultant relapses.

Identification of a region of PfEMP1 that mediates adherence of Plasmodium falciparum infected erythrocytes to CD36: conserved function with variant sequence

Adherence of mature parasitized erythrocytes (PE) of Plasmodium falciparum to microvascular endothelial cells contributes directly to the virulence and pathology of this human malaria. The malarial variant antigen, P falciparum erythrocyte membrane protein 1 (PfEMP1), has been implicated as the PE receptor for CD36 on endothelial cells. We identified the region of PfEMP1 that mediates adherence of PE to CD36 and showed that a recombinant protein fragment from this region blocked and reversed adherence of antigenically different parasites. Sequence variation was evident in the CD36 binding domain of different PfEMP1 genes, yet many highly conserved residues, particularly cysteine residues, are evident. This suggests a highly conserved shape that mediates adherence to CD36. Immunization with the CD36-binding domain elicited sera that are cross-reactive with the different recombinant proteins but are strain-specific for the PE surface. Novel anti-adherence therapeutics and a malaria vaccine may derived from exploitation of the structure of the CD36 binding domain of PfEMP1.