Potentiality of actinobacteria to combat against biotic and abiotic stresses in tea [Camellia sinensis (L) O. Kuntze]

Tea (Camellia sinensis (L) O. Kuntze) is a long-duration monoculture crop prone to several biotic (fungal diseases and insect pest) and abiotic (nutrient deficiency, drought and salinity) stress that eventually result in extensive annual crop loss. The specific climatic conditions and the perennial nature of the tea crop favour growth limiting abiotic factors, numerous plant pathogenic fungi (PPF) and insect pests. The review focuses on the susceptibility of tea crops to PPF/pests, drought, salinity and nutrient constraints and the potential role of beneficial actinobacteria in promoting tea crop health. The review also focuses on some of the major PPF associated with tea, such as Exobasidium vexans, Pestalotiopsis theae, Colletotrichum acutatum, and pests (Helopeltis theivora). The phylum actinobacteria own a remarkable place in agriculture due to the biosynthesis of bioactive metabolites that assist plant growth by direct nutrient assimilation, phytohormone production, and by indirect aid in plant defence against PPF and pests. The chemical diversity and bioactive significance of actinobacterial metabolites (antibiotics, siderophore, volatile organic compounds, phytohormones) are valuable in the agro-economy. This review explores the recent history of investigations in the role of actinobacteria and its secondary metabolites as a biocontrol agent and proposes a commercial application in tea cultivation.     

Myocardial ischemia-reperfusion injury is enhanced in a model of systemic allergy and asthma

Despite epidemiological evidence of cardiovascular complications in asthmatics, the direct contribution of asthmatic pathophysiology to cardiovascular effects is unknown. Considering parallels in underlying pathophysiology, we tested the hypothesis that presence of systemic allergy and asthma worsens the outcome of myocardial ischemia-reperfusion injury. Systemic allergy and asthma were created in rabbits by repeated intraperitoneal injections of allergen with adjuvant, followed by an airway challenge in two groups. Nonsensitized animals served as controls. In situ myocardial ischemia-reperfusion was induced in anesthetized animals by a 30-min ligation of a coronary artery, followed by 3 h of reperfusion. Ischemia-reperfusion was done at 24 h after intraperitoneal boost (1 DB) and 7 days (7 DB) after the last intraperitoneal injection and at 24 h (1DAWCH) and 7 days (7DAWCH) after airway challenge. The infarct size (determined by 2,3,5-triphenyltetrazolium chloride staining, normalized to area at risk) was significantly higher in all sensitized groups compared with control (1DB, 31 +/- 4; 7DB, 28.9 +/- 2.6; 1DAWCH, 66.1 +/- 4.1; 7DAWCH, 28.9 +/- 9.2; control, 16.7 +/- 3.2; means +/- SE; P < 0.01 by ANOVA; n = 6). The 1DAWCH group showed significantly greater infarct than all other groups (P < 0.05). Myocardial neutrophil infiltration was significantly higher in the sensitized groups compared with control (P < 0.01). Tissue neutrophil counts showed a strong positive correlation to infarct sizes (r2 = 0.9). These observations indicate that the presence of systemic allergy and asthma is associated with increased myocardial neutrophil infiltration during acute ischemia-reperfusion and increased size of the resulting infarct.     

Differential tissue expression of three 35-kDa annexin calcium-dependent phospholipid-binding proteins

We have purified three 35-kDa calcium- and phospholipid-binding proteins from rat liver. These three calcimedins bind to phosphatidylserine in a calcium-dependent manner and have been termed 35 alpha, 35 beta, and 35 gamma based on their relative charge as determined by isoelectric focusing. Purification of the three 35-kDa calcimedins is achieved by phenyl-Sepharose, ion exchange, and gel filtration chromatography. Antibody was produced against the annexin consensus peptide, Lys-Ala-Met-Lys-Gly-Leu-Gly-Thr-Asp-Glu, which was derived from the sequence of several Ca2+/phospholipid-binding proteins including calpactin, lipocortin, endonexin II, 67-kDa calelectrin, lymphocyte 68-kDa protein, and protein II. Recognition of each 35-kDa calcimedin by anticonsensus sequence antibody places them in this protein family. Antibodies against each 35-kDa calcimedin were raised and purified by antigen-affinity chromatography. Each antibody is monospecific for the respective 35-kDa calcimedin. Immunological cross-reactivity defines 35 alpha, 35 beta, and 35 gamma as lipocortins III, IV, and V, respectively. Surveys by immunoblot analysis using these monospecific antibodies demonstrate a markedly different tissue expression pattern for each 35-kDa calcimedin. Furthermore, the levels of 35 alpha, 35 beta, and 35 gamma are differentially regulated in maturing rat ovary and uterus. Each calcimedin has been localized by indirect immunofluorescence within specific cell types. These results support the concept that mediation of the intracellular calcium signal can occur via multiple pathways through several related yet independent mediator proteins.     

Body temperature and thermoregulation ofAntheraea assama larvae

Activity patterns and body temperature (T _b ) and its maintenance were investigated in the 5th instar larvae ofAntheraea assama Westwood (Lepidoptera: Saturniidae). These larvae thermoregulate by finding and utilizing favourable microenvironments and by restricting their activities to suitable times of the day. Further convective cooling, facilitated by a raised posture also serves to ameliorate T_b. Regression analysis suggests that environmental temperature is the major determinant of T_b along with solar radiation (SR) and wind (W).     

Antibody against a cystic fibrosis transmembrane conductance regulator-derived synthetic peptide inhibits anion currents in human colonic cell line T84.

The cystic fibrosis (CF) phenotype is characterized by a regulatory defect in Cl- permeability in epithelia. A gene (250,000 base pairs) that is associated with this autosomal genetic disorder has been identified. To determine the cellular function of the recently cloned gene product, the cystic fibrosis transmembrane conductance regulator (CFTR), we have produced antibody against a synthetic peptide deduced from the CFTR cDNA sequence corresponding to positions 505-511. This site includes phenylalanine 508, the deletion of which is the most commonly expressed mutation in CF. We sought to determine whether the anti-CFTR505-511 peptide antibody could modulate the activation of the volume-sensitive, Ca(2+)-dependent, as well as the cAMP-dependent Cl- conductances present in the Cl(-)-secreting human colonic T84 cell line. Affinity-purified anti-CFTR505-511 antibody was introduced into the cytoplasm of individual T84 cells and its function studied using the whole-cell patch-clamp technique. Although cAMP-dependent Cl- current activation was inhibited in cells perfused with the anti-CFTR505-511 peptide antibody, Ca(2+)-dependent anion current activation remained unaffected. Chloride current activation, which accompanies cellular swelling, was partially attenuated in anti-CFTR505-511 antibody-loaded cells as compared with control cells perfused with either saline or irrelevant antibody. These results further support a role for CFTR in anion transport in epithelial cells and suggest its possible involvement in a number of anion transport pathways in chloride secretory epithelia.     

Transgenic Tea Over-expressing <Emphasis Type="Italic">Solanum tuberosum Endo</Emphasis>-1,3-beta-<Emphasis Type="SmallCaps">d</Emphasis>-glucanase Gene Conferred Resistance Against Blister Blight Disease

Tea (Camellia sinensis [L.] O. Kuntze) plant, one of the most important plantation crops in the world, is infected by a fungus called Exobasidium vexans leading to dreaded blister blight disease. The disease may result in crop losses up to 35% which directly affect the tea industry. Solanum tuberosum endo-1,3-beta-d-glucanase was cloned into tea genome via Agrobacterium-mediated transformation. The transformation event initially gave 32 kanamycin-resistant plantlets, out of which PCR analysis confirmed only 10 plantlets about the integration of transgene in the plant genome. Real-time PCR study detected transgene expression in six transgenic plantlets. Upregulation of endogenous C. sinensis pathogenesis-related (PR) genes like PR3 (chitinase I) gene and PR5 (thaumatin-like protein) gene also occurred in transgenic plantlets. Detached leaf infection assay showed resistance to E. vexans in greenhouse-acclimated transgenic plantlets. An inhibitory activity against E. vexans was noticed on the detached leaves of transgenic plantlets compared to control. Transgenic plantlets showed resistance to inoculated fungal pathogen by the formation of hypersensitivity reaction area unlike the formation of fungal lesion on control plantlet. Thus, it can be inferred that constitutive expression of the potato endo-1,3-beta-d-glucanase gene can be a strategy to produce blister blight-resistant tea.     

Verotoxic Escherichia coli (STEC) from beef and its products

In the present investigation, out of 27 (24.10%) strains of Escherichia coli isolated from 112 beef samples comprising raw meat (45), kabab (36) and kofta (31), 9 (33.33%) belonging to 7 different serotypes were verotoxic as tested by vero cell cytotoxic assay. Serotype O145 was the predominant STEC in raw meat. Interestingly, one STEC-O157 strain was also detected. All the STEC strains were positive for Stx genes by polymerase chain reaction showing stx2 (77.78%) to be most predominant followed by stx1 (22.22%). Phenotypic enterohaemolysin production on washed sheep blood agar supplemented with CaCl2 revealed 6 (66.67%) STEC strains to be positive. Presence of STEC in cooked beef products, viz., kabab and kofta appeared to be a matter of concern and potential threat to public health.     

Establishment of dedifferentiated callus of haploid origin from unfertilized ovaries of tea (Camellia sinensis (L.) O. Kuntze) as a potential source of total phenolics and antioxidant activity

This is the first report of induction of haploid callus with significant antioxidant activity from unpollinated ovary cultures of tea. Out of the five cultivars tested, TV18 gave the highest percentage of callus induction. Within 1 wk of induction, ovules swelled to almost double their original size, and white, friable callus emerged. A high cytokinin/auxin ratio, provided by 8.5 μM benzyl adenine and 4.5 μM 2,4-dichlorophenxyacetic acid, and high-temperature treatment (33°C) for 10 d in the dark promoted maximum callus induction. Callus was maintained on MS medium containing 22.2 μM benzyl adenine and 9.8 μM indolebutyric acid (callus line RM 1) in the light at 25°C. Well-developed tracheids were formed within 4 wk in callus subcultured on MS medium containing 1.8 μM thidiazuron and 5.0 μM 2,3,5-triiodobenzoic acid (line RM 2). Flow cytometric analysis revealed that most cells were haploid. Both RM 1 and RM 2 produced phenolic compounds with significant antioxidant capacity. Phenolic content showed a positive linear correlation with antioxidant activity. The total phenolic content of RM 1 was 3.47?±?0.21 gallic acid equivalents (GAE) mg/g dry weight and that of RM 2 was 2.39?±?0.12 GAE mg/g dry weight. Antioxidant activity was measured using IC₅₀, a measure of inhibitory concentration; a lower IC₅₀ value reflects greater antioxidant activity. The IC₅₀ value of RM 1 was 2,530 μg/ml and that of RM 2 was 3,170 μg/ml. The results suggested that the phenolic compounds contributed significantly to the antioxidant capacity of the in vitro cell lines.     

Esterification of lauric acid with lauryl alcohol using cross-linked enzyme crystals: Solvent effect and kinetic study

In this paper, we report a comprehensive kinetic study on esterification of lauric acid with lauryl alcohol catalysed by commercial porcine pancreatic lipase (PPL) in the form of cross-linked enzyme crystals (CLEC) using glutaraldehyde as the cross linker. The stability of the CLEC was better than the immobilized enzyme for practical applications. Comparative studies using six different solvents having hydrophobicity (log p) values ranging from 0.70 to 3.50 revealed that the esterification reaction was favoured in hydrophobic solvents. The kinetics of the esterification reaction conformed with the so-called Ping-Pong–Bi-Bi mechanism with alcohol inhibition.     

Acremonium strictum: Report of a Rare Emerging Agent of Cutaneous Hyalohyphomycosis with Review of Literatures

We present a case of cutaneous hyalohyphomycosis due to Acremonium strictum in an immunocompetent individual along with an overview of fungal infections caused by A. strictum. The diagnosis was confirmed by the presence of hyphae in microscopic examination of cutaneous biopsy and discharge, positive culture for A. strictum and sequencing of the isolate at reference centre. The infection resolved with itraconazole and terbinafine. Cutaneous or subcutaneous infections of A. strictum have rarely been reported. Fungemia or disseminated infection often with fatal outcome in immunocompromised patients was the most common presentation of A. strictum infection found in the literatures. The studies also reveal worldwide variation in the treatment regime and outcome of the treatment.