A comparative account of the microbiological characteristics of soils under natural forest,grassland and cropfield from Eastern India

Microbiological and physico-chemical characteristics of tropical forest, grassland and cropfield soils from India were investigated. The study revealed that the conversion of natural forest led to a reduction of soil organic C (26–36%), total N (26–35%), total P (33–44%), microfungal biomass (44–66%) and total microbial biomass C, N and P (25–60%) over a period of 30–50 years. Comparative analysis of microbial activity in terms of basal soil respiration revealed maximum activity in the forest and minimum in the cropfield soil. Analysis of microbial metabolic respiratory activity (qCO₂) indicated relatively greater respiratory loss of CO₂-C per unit microbial biomass in cropfield and grassland than in forest soil. Considering the importance of the microbial component in soil, we conclude that the conversion of the tropical forest to different land uses leads to the loss of biological stability of the soil.     

Investigation on the Fusarium induced stress protein (FISP) in wheat: Immunolocalisation in root cells

Abstract

Fusarium induced-stress-protein (FISP) of ～51 kDa molecular mass was detected in seven day old germinated wheat (Triticum aestivum var Sonalika) seedlings infected with F. oxysporum for a period of seven days. This particular stress protein (FISP) of ～51 kDa was over-expressed in the case of Fusarium infected seedlings compared to the untreated seedlings where the presence of this protein was insignificant. Localisation of this ～51 kDa protein in root tissue by anti-CSAP (Cadmium Stress Associated Protein) antiserum showed a significantly higher number of gold particles in the case of Fusarium infected root tissue compared to the untreated control. A unique type of organised localisation of FISP around the plasma membrane and outer vacuolar membrane suggests its defensive role against Fusarium infection that might be a general stress protein against biotic and abiotic stresses.     

Oxidative burden and antioxidant defense system in polymorphonuclear leukocytes of human lung diseases

Superoxide anion (O2.-) and hydrogen peroxide (H2O2) production was significantly higher in blood neutrophils (PMNs) of patients with lung cancer and non-malignant lung diseases when compared to the controls (p<0.001). Superoxide dismutase (SOD) activity was significantly decreased in PMNs of patients with lung cancer (p<0.001). Similarly, catalase and glutathione peroxidase (GPx) activities were lower in PMNs of lung cancer patients as compared to non-malignant lung diseases and controls. There was an increase in HMP shunt activity as measured by rate of formation of 14CO2 from [1-14C]-glucose in PMNs of lung cancer patients. Modifications in the antioxidant defense system in PMNs of malignant and nonmalignant lung diseases, the changes being more in the malignancy are indicated.     

Entry of bovine viral diarrhea virus into ovine cells occurs through clathrin-dependent endocytosis and low pH-dependent fusion

Although mechanisms of bovine viral diarrhea virus (BVDV) entry into bovine cells have been elucidated, little is known concerning pestivirus entry and receptor usage in ovine cells. In this study, we determined the entry mechanisms of BVDV-1 and BVDV-2 in sheep fetal thymus cells. Both BVDV-1 and BVDV-2 infections were inhibited completely by chlorpromazine, β-methyl cyclodextrin, sucrose, bafilomycin A1, chloroquine, and ammonium chloride. Simultaneous presence of reducing agent and low pH resulted in marked loss of BVDV infectivity. Moreover, BVDV was unable to fuse with ovine cell membrane by the presence of reducing agent or low pH alone, while combination of both led to fusion at low efficiency. Furthermore, sheep fetal thymus cells acutely infected with BVDV-1 or BVDV-2 were found protected from heterologous BVDV infection. Taken together, our results showed for the first time that entry of both BVDV-1 and BVDV-2 into ovine cells occurred through clathrin-dependent endocytosis, endosomal acidification, and low pH-dependent fusion following an activation step, besides suggesting the involvement of a common ovine cellular receptor during attachment and entry.     

Ethanol fermentation of mahula (<Emphasis Type="Italic">Madhuca latifolia</Emphasis>) flowers using free and immobilized bacteria <Emphasis Type="Italic">Zymomonas mobilis</Emphasis> MTCC 92

Mahula (Madhuca latifolia L.) is a deciduous tree commonly found in the tropical rain forests of Asian and Australian continent. Corolla, the edible part of its flowers, is rich in fermentable sugar (37 ± 0.23%; on dry weight basis). Batch fermentation of mahula flowers was carried out using Zymomonas mobilis MTCC 92 free cells and cells immobilized in calcium alginate matrix. The ethanol productions were 122.9 ± 0.972 and 134.6 ± 0.104 g/kg flowers on dry weight basis using free and immobilized cells, respectively, after 96 h of fermentation, which showed that cells entrapped in calcium alginate matrix yielded 8.7% more ethanol than free cells. Further, the immobilized cells were physiologically active up to three more cycles of fermentation producing 132.7 ± 0.095, 130.5 ± 0.09 and 128.7 ± 0.056 g ethanol per kg flower in first, second and third cycle, respectively.     

Mercaptoethylpyrazine promoted electrochemistry of redox protein and amperometric biosensing of uric acid

Electrochemistry of microperoxidase-11 (MPx-11) anchored on the mixed self-assembled monolayer (SAM) of 2-(2-mercaptoethylpyrazine) (PET) and 4,4'-dithiodibutyric acid (DTB) on gold (Au) electrode and the biosensing of uric acid (UA) is described. MPx-11 has been covalently anchored on the mixed SAM of PET and DTB on Au electrode. MPx-11 on the mixed self-assembly exhibits reversible redox response characteristic of a surface confined species. The heterocyclic ring of PET promotes the electron transfer between the electrode and the redox protein. The apparent standard rate constant kapps obtained for the redox reaction of MPx-11 on the mixed monolayer is approximately 2.15 times higher than that on the single monolayer of DTB modified electrode. MPx-11 efficiently mediates the electrocatalytic reduction of H2O2. MPx-11 electrode is highly sensitive to H2O2 and it shows linear response for a wide concentration range. The electrocatalytic activity of the MPx-11 electrode is combined with the enzymatic activity of uricase (UOx) to fabricate uric acid biosensor. The bienzyme assembly is highly sensitive towards UA and it could detect UA as low as 2 microM at the potential of -0.1 V. The biosensor shows linear response with a sensitivity of 3.4+/-0.08 nA cm(-2) microM(-1). Ascorbate (AA) and paracetamol (PA) do not significantly interfere in the amperometric sensing of UA.     

High frequency plantlet regeneration from cotyledonary node cultures of <Emphasis Type="Italic">Aegle marmelos</Emphasis> (L.) Corr.

High frequency plantlet regeneration was achieved in cotyledonary nodes of Aegle marmelos. Cotyledonary nodes from 1 mo. old in vitro grown seedlings of A. marmelos were cultured on Murashige and Skoog (MS) medium supplemented with benzyl adenine (BA) (0–8.8 μM), kinetin (KIN) (0–9.4 μM), and indole-3-acetic acid (IAA) (0–1.14 μM) either alone or in combinations. The highest regenerative response was observed on medium containing 6.6 μM BA + 1.14 μM IAA where approximately 86.6% of the cultures responded with an average shoot numbers of 487.5 per explant in 7-wk time. Cultures maintained on KIN-supplemented medium showed very poor response. In vitro responded shoots were transferred to root induction medium consisting of half-strength MS supplemented with auxins IAA, indole-3-butyric acid (IBA), or α-naphthalene acetic acid (NAA). Rooting was best in medium supplemented with 14.7 μM IBA. Rooted plantlets were acclimatized and transferred to the field with 80% survival rate.     

The EF-Hand Ca2+ Binding Protein MICU Choreographs Mitochondrial Ca2+ Dynamics in Arabidopsis

Plant organelle function must constantly adjust to environmental conditions, which requires dynamic coordination. Ca²⁺ signaling may play a central role in this process. Free Ca²⁺ dynamics are tightly regulated and differ markedly between the cytosol, plastid stroma, and mitochondrial matrix. The mechanistic basis of compartment-specific Ca²⁺ dynamics is poorly understood. Here, we studied the function of At-MICU, an EF-hand protein of Arabidopsis thaliana with homology to constituents of the mitochondrial Ca²⁺ uniporter machinery in mammals. MICU binds Ca²⁺ and localizes to the mitochondria in Arabidopsis. In vivo imaging of roots expressing a genetically encoded Ca²⁺ sensor in the mitochondrial matrix revealed that lack of MICU increased resting concentrations of free Ca²⁺ in the matrix. Furthermore, Ca²⁺ elevations triggered by auxin and extracellular ATP occurred more rapidly and reached higher maximal concentrations in the mitochondria of micu mutants, whereas cytosolic Ca²⁺ signatures remained unchanged. These findings support the idea that a conserved uniporter system, with composition and regulation distinct from the mammalian machinery, mediates mitochondrial Ca²⁺ uptake in plants under in vivo conditions. They further suggest that MICU acts as a throttle that controls Ca²⁺ uptake by moderating influx, thereby shaping Ca²⁺ signatures in the matrix and preserving mitochondrial homeostasis. Our results open the door to genetic dissection of mitochondrial Ca²⁺ signaling in plants.