Dinesh Raj Modi

Biocontrol potential of Trichoderma species against mango malformation pathogens

Malformation disease of Mango (Mangifera indica L.) caused by Fusarium moniliforme var. subglutinans is one of the most destructive diseases, which is a major production constraint in the mango-growing regions of India. In this study, The bioagents Trichoderma viride (Tr1), Trichoderma virens (Tr2) and Trichoderma harzianum (Tr3) were evaluated in culture with the pathogens to monitor the antagonistic effect and their volatile compound and culture filtrates (non-volatile compound). It was found that all the three isolates of bioagents significantly checked the growth of F. moniliforme var. subglutinans. In dual culture, the best result was obtained with T. harzianum followed by T. virens and T. viride. A similar result was also observed in the case of culture filtrates ofTrichoderma spp. The results clearly showed that inhibition of the growth of the fusaria isolates by T. harzianum was significantly superior to T. viride andT.virens. In case of antifungal activity of volatile compounds released by Trichoderma isolates, it was also observed that T. virens was more superior to T.harzianum and T. viride.

Iodine plus n-3 fatty acid supplementation augments rescue of postnatal neuronal abnormalities in iodine-deficient rat cerebellum.

High prevalence of hypothyroxinaemia in iodine-deficient (ID) mothers has serious implications for mental health of the progeny. Independent supplementation of iodine and n-3 fatty acids (FA) markedly improves growth and cognitive performance of school children. Discerning effects of n-3 FA and iodine on the developing cerebellum have not been ascertained. The present study investigates effects of these two micronutrients separately as well as together in an ID rat model. We studied the effects of these micronutrients on progeny of ID dams by instituting the following supplementation diets: (1) low-iodine diet (LID), (2) LID+potassium iodide (KI), (3) LID+n-3 FA and (4) LID+KI+n-3 FA. Pups were investigated for morphological and biochemical parameters at the peak of cerebellar histogenesis on postnatal day (P) 16 and for neurobehavioural as well as motor coordination parameters at P40. Results indicate that n-3 FA alone, without improvement in circulating thyroid hormone (TH), significantly improves functional, morphological and biochemical indices of the developing cerebellum. Further, results show that co-supplementation with iodine and n-3 FA rescues not only the loss of neurotrophic support, but also salvages motor coordination, memory and learning. This additive effect results in significantly improving neurotrophic support and seems to be mediated by parallel significant increase in TH receptor (TR)α and normalisation of TRβ, retinoic orphan receptor α and p75 neurotrophin receptor, as well as noteworthy prevention of apoptotic cell death and strengthening of anti-oxidative defence. The overall results indicate important mitigating role that n-3 FA may play in enhancing TH nuclear receptor-mediated signalling in the developing cerebellum.

Metabolite assignment of ultrafiltered synovial fluid extracted from knee joints of reactive arthritis patients using high resolution NMR spectroscopy

Currently, there are no reliable biomarkers available that can aid early differential diagnosis of reactive arthritis (ReA) from other inflammatory joint diseases. Metabolic profiling of synovial fluid (SF)—obtained from joints affected in ReA—holds great promise in this regard and will further aid monitoring treatment and improving our understanding about disease mechanism. As a first step in this direction, we report here the metabolite specific assignment of 1H and 13C resonances detected in the NMR spectra of SF samples extracted from human patients with established ReA. The metabolite characterization has been carried out on both normal and ultrafiltered (deproteinized) SF samples of eight ReA patients (n = 8) using high‐resolution (800 MHz) 1H and 1H─13C NMR spectroscopy methods such as one‐dimensional 1H CPMG and two‐dimensional J‐resolved1H NMR and homonuclear 1H─1H TOCSY and heteronuclear1H─13C HSQC correlation spectra. Compared with normal SF samples, several distinctive 1H NMR signals were identified and assigned to metabolites in the 1H NMR spectra of ultrafiltered SF samples. Overall, we assigned 53 metabolites in normal filtered SF and 64 metabolites in filtered pooled SF sample compared with nonfiltered SF samples for which only 48 metabolites (including lipid/membrane metabolites as well) have been identified. The established NMR characterization of SF metabolites will serve to guide future metabolomics studies aiming to identify/evaluate the SF‐based metabolic biomarkers of diagnostic/prognostic potential or seeking biochemical insights into disease mechanisms in a clinical perspective.

NMR based serum metabolomics revealed distinctive metabolic patterns in Reactive Arthritis compared to Rheumatoid Arthritis

Reactive arthritis (ReA) is a member of seronegative spondyloarthropathy (SSA), which involves an acute/subacute onset of asymmetrical lower limb joint inflammation weeks after a genitourinary/gastrointestinal infection. The diagnosis is clinical because it is difficult to culture the microbes from synovial fluid. Arthritis patients with a similar clinical picture but lapsed history of an immediate preceding infection that do not fulfill the diagnostic criteria of other members of SSA, such as ankylosing spondylitis, psoriatic arthritis, and arthritis associated with inflammatory bowel disease, are labeled as peripheral undifferentiated spondyloarthropathy (uSpA). Both ReA and uSpA patients show a strong association with class I major histocompatibility complex allele, HLA-B27, and a clear association with an infectious trigger; however, the disease mechanism is far from clear. Because the clinical picture is largely dominated by rheumatoid-arthritis (RA)-like features including elevated levels of inflammatory markers (such as ESR, CRP, etc.), these overlapping symptoms often confound the clinical diagnosis and represent a clinical dilemma, making treatment choice more generalized. Therefore, there is a compelling need to identify biomarkers that can support the diagnosis of ReA/uSpA. In the present study, we performed NMR-based serum metabolomics analysis and demonstrated that ReA/uSpA patients are clearly distinguishable from controls and further that these patients can also be distinguished from the RA patients based on the metabolic profiles, with high sensitivity and specificity. The discriminatory metabolites were further subjected to area under receiver operating characteristic curve analysis, which led to the identification of four metabolic entities (i.e., valine, leucine, arginine/lysine, and phenylalanine) that could differentiate ReA/uSpA from RA.

Decreased level of histone acetylation in the infralimbic prefrontal cortex following immediate extinction may result in deficit of extinction memory

In the last few decades, there has been exponential increase in studies aiming to trace the molecular mechanism of fear extinction with a hope to minimize the return of fear after exposure therapy required for operational treatment of anxiety disorders. The present study explored how the timing of extinction training after developing a specific fear, affects the consequent return of the extinguished fear and the role of histone acetylation in controlling the circuitry, thereof. It was found that rats undergone extinction training 10 min. after fear memory acquisition (Immediate Extinction) had deficits in retention of extinction memory as compared to one which underwent extinction 24 h after fear acquisition (Delayed Extinction). When the differences were sorted at the circuitry level the relative activity of the infralimbic prefrontal cortex (IL) to prelimbic cortex (PL) was found to be lower in the immediate extinction group as compared to the delayed extinction group as evidenced by the c-fos expression in the mPFC of these groups. Further investigation showed that acetylation of histone H3/H4 along with the levels of CREB binding protein (CBP) which is a histone acetyltransferase (HAT), was associated with neuronal activation and was significantly lower in the IL of the immediate extinction group than the delayed extinction group. In conclusion, the observed deficits in the immediate extinction group may be the result of compromised activation of IL, which in turn may be associated with changes in histone acetylation.

Identification and characterization of Fusarium mangiferae as pathogen of mango malformation in India

Fusarium mangiferae (=F. subglutinans) isolates collect from malformed samples from major mango-growing area of North India. Molecular identification and characterization of eleven most virulent isolates of F. mangiferae, based on pathogenicity tests used for the present study. Species-specific, genus specific ITS-PCR and PCR-RFLP performed for the accurate and easy detection of F. mangiferae. The rDNA-ITS 28S region sequences used for phylogenetic analysis of Fusarium isolates from India and other countries for homology search between them. The phylogenetic tree divided the isolates into three clades (i.e., American, Asian and African) and showed the high level of sequence based similarity (69-99%) among all Fusarium sequences from Asia. Thus, claimed Fusarium mangiferae as dominant pathogen of mango malformation. Furthermore, we conclude that exploiting the nested PCR coupled with PCR-RFLP will help in rapid and accurate detection of F. mangiferae pathogen of mango malformation.

Hisopathological Study of Healthy and Malformed Tissues of Mango (Mangifera indica L.)

Malformation is a serious threat to mango production in India and other mango growing countries (tropical and subtropical) of the world. The disease is widespread in flowers and vegetative shoots. It has a crippling effect on mango production causing heavy economic losses. Mango Malformation Disease is a fungal disease caused by Fusarium moniliforme var. subglutinans. Symptoms of the disease include loss of the apical dominance and swelling of vegetative buds, proliferation of leaves and flowers, phyllody and hypertrophy of panicle axes. Histopathological observations of malformed shoots and penical reveal occasional inter-and intracellular distribution of fungal hyphae in cortex, phloem and parenchymatous pith cell. Fungal mycelium has also been detected at the juncture of the shoot tip in malformed axillary buds, axes of petels and sepals of malformed buds, and in the degenerating embryos of mustard stage malformed fruits.