Sink development, sucrose metabolising enzymes and carbohydrate status in turnip (Brassica rapa L.)

Accumulation of 60–70 % of biomass in turnip root takes place between 49–56 days after sowing. To understand the phenomenon of rapid sink filling, the activities of sucrose metabolising enzymes and carbohydrate composition in leaf blades, petiole and root of turnip from 42–66 days of growth were determined. An increase (2–3 folds) in glucose and fructose contents of roots accompanied by an increase in activities of acid and alkaline invertases was observed during rapid biomass accumulating phase of roots. The observed decrease in the activities of acid and alkaline invertases along with sucrose synthase (cleavage) in petiole during this period could facilitate unrestricted transport of sucrose from leaves to the roots. During active root filling period, a decrease in sucrose synthase (cleavage) and alkaline invertase activities was also observed in leaf blades. A rapid decline in the starch content of leaf blades was observed during the phase of rapid sink filling. These metabolic changes in the turnip plant led to increase in hexose content (35–37 %) of total dry biomass of roots at maturity. High hexose content of the roots appears to be due to high acid invertase activity of the root.     

Effect of Trichodesma indicum extract on cough reflex induced by sulphur dioxide in mice.

The effect of methanol extract of whole plants of Trichodesma indicum R. Br. has been investigated on sulphur dioxide (SO2) induced cough reflex in Swiss albino mice. The extract has demonstrated significant (p < 0.001) inhibition in frequency of cough in all the tested doses when compared with untreated control group. The effect persisted up to 90 min of its oral administration and also comparable to that of the effect exhibited by the standard drug (Codeine phosphate). This study confirmed the traditional use of this plant in the treatment of cough. Determination of underlying mechanism of beneficial effect is major topic requiring further comprehensive investigation.     

Design of liposome to improve encapsulation efficiency of gelonin and its effect on immunoreactivity and ribosome inactivating property

Gelonin, purified from the seeds of Gelonium multiflorum, using cation-exchange and gel-filtration chromatography was characterised for its purity, homogeneity and molecular weight by reverse-phase HPLC (RP-HPLC) and SDS-PAGE analysis. The HPLC purified gelonin was used for entrapment studies in the liposomes. Liposomes were prepared by reverse phase evaporation (REV) technique using three different types of lipid composition in the same molar ratio. The method resulted in 75–80% entrapment efficiency of gelonin in the liposomes. Entrapped and unentrapped gelonin was characterized for physico-chemical, immunochemical and biological properties. The immunoreactivity of entrapped gelonin was fully preserved but the ribosome-inactivating property was slightly inhibited. The method involved mild conditions, highly reproducible and the liposomes produced appeared to be stable for several months. It has important implications in the development of cell type specific cytotoxic agents where a chemical cross-linking is involved which significantly inhibits both immunoreactivity and ribosome-inactivating ability of the toxin.     

Infection with the Lyme disease pathogen suppresses innate immunity in mice with diet‐induced obesity

Obesity is a major global public health concern. Immune responses implicated in obesity also control certain infections. We investigated the effects of high‐fat diet‐induced obesity (DIO) on infection with the Lyme disease bacterium Borrelia burgdorferi in mice. DIO was associated with systemic suppression of neutrophil‐ and macrophage‐based innate immune responses. These included bacterial uptake and cytokine production, and systemic, progressive impairment of bacterial clearance, and increased carditis severity. B. burgdorferi‐infected mice fed normal diet also gained weight at the same rate as uninfected mice fed high‐fat diet, toll‐like receptor 4 deficiency rescued bacterial clearance defects, which greater in female than male mice, and killing of an unrelated bacterium (Escherichia coli) by bone marrow‐derived macrophages from obese, B. burgdorferi‐infected mice was also affected. Importantly, innate immune suppression increased with infection duration and depended on cooperative and synergistic interactions between DIO and B. burgdorferi infection. Thus, obesity and B. burgdorferi infection cooperatively and progressively suppressed innate immunity in mice.     

Evidence of salicylic acid pathway with EDS1 and PAD4 proteins by molecular dynamics simulation for grape improvement

Biotic stress is a major cause of heavy loss in grape productivity. In order to develop biotic stress-resistant grape varieties, the key defense genes along with its pathway have to be deciphered. In angiosperm plants, lipase-like protein phytoalexin deficient 4 (PAD4) is well known to be essential for systemic resistance against biotic stress. PAD4 functions together with its interacting partner protein enhanced disease susceptibility 1 (EDS1) to promote salicylic acid (SA)-dependent and SA-independent defense pathway. Existence and structure of key protein of systemic resistance EDS1 and PAD4 are not known in grapes. Before SA pathway studies are taken in grape, molecular evidence of EDS1: PAD4 complex is to be established. To establish this, EDS1 protein sequence was retrieved from NCBI and homologous PAD4 protein was generated using Arabidopsis thaliana as template and conserved domains were confirmed. In this study, computational methods were used to model EDS1 and PAD4 and simulated the interactions of EDS1 and PAD4. Since no structural details of the proteins were available, homology modeling was employed to construct three-dimensional structures. Further, molecular dynamic simulations were performed to study the dynamic behavior of the EDS1 and PAD4. The modeled proteins were validated and subjected to molecular docking analysis. Molecular evidence of stable complex of EDS1:PAD4 in grape supporting SA defense pathway in response to biotic stress is reported in this study. If SA defense pathway genes are explored, then markers of genes involved can play pivotal role in grape variety development especially against biotic stress leading to higher productivity.     

Asp1080 upstream of the calmodulin-binding domain is critical for autoinhibition of hPMCA4b

The role of the plasma membrane Ca(2+) pump (PMCA) is to remove excess Ca(2+) from the cytosol to maintain low intracellular Ca(2+) levels. Asp(1080) lies within an acidic sequence between the C-terminal inhibitory region and the catalytic core of PMCAs and is part of the caspase-3 recognition site of isoform 4b. Caspase-3 cuts immediately after this residue and activates the pump by removing the inhibitory region (Pászty, K., Verma, A. K., Padányi, R., Filoteo, A. G., Penniston, J. T., and Enyedi, A. (2002) J. Biol. Chem. 277, 6822-6829). Asp(1080) had not been believed to have any other role, but here we show that it also plays a critical role in the autoinhibition and calmodulin activation of PMCA4b. Site-specific mutation of Asp(1080) to Asn, Ala, or Lys in PMCA4b resulted in a substantial increase in the basal activity in the absence of calmodulin. All Asp(1080) mutants exhibited an increased affinity for calmodulin because of an increase in the rate of activation by calmodulin. This rate was higher when the inhibition was weaker, showing that a strong inhibitory interaction slows the activation rate. In contrast, mutating the nearby Asp(1077) had no effect on basal activity or calmodulin activation. We propose that the conserved Asp(1080), even though it is neither in the regulatory domain nor in the catalytic core, plays an essential role in inhibition by stabilizing the inhibited state of the enzyme.     

Comparison of three rat models of cerebral vasospasm

A substantial number of rat models have been used to research subarachnoid hemorrhage-induced cerebral vasospasm; however, controversy exists regarding which method of selection is appropriate for this species. This study was designed to provide extensive information about the three most popular subarachnoid hemorrhage rat models: the endovascular puncture model, the single-hemorrhage model, and the double-hemorrhage model. In this study, the basilar artery and posterior communicating artery were chosen for histopathological examination and morphometric analysis. Both the endovascular puncture model and single-hemorrhage model developed significant degrees of vasospasm, which were less severe when compared with the double-hemorrhage model. The endovascular puncture model and double-hemorrhage model both developed more vasospasms in the posterior communicating artery than in the basilar artery. The endovascular puncture model has a markedly high mortality rate and high variability in bleeding volume. Overall, the present study showed that the double-hemorrhage model in rats is a more suitable tool with which to investigate mechanism and therapeutic approaches because it accurately correlates with the time courses for vasospasm in humans.     

Antioxidant response and Lea genes expression under exogenous ABA and water deficit stress in wheat cultivars contrasting in drought tolerance

Two wheat (Triticum aestivum) cultivars, C306 (drought tolerant) and PBW343 (drought susceptible) were compared for their response to exogenous ABA, water stress (WS) and combined (ABA plus WS) during their seedlings growth. Their responses were studied in the form of seedlings growth, antioxidant potential of roots and shoots and expression levels of LEA genes in shoots. ABA treatment led to increase in levels of ascorbate, ascorbate to dehydroascorbate ratio, antioxidant enzymes and decreases in levels of dehydroascorbate, malondialdehyde (MDA). Decrease in biomass, ascorbate contents, ascorbate to dehydroascorbate ratios and antioxidant enzymes was more in PBW343 than in C306 under WS. Dehydroascorbate and MDA levels were higher in PBW343 than in C306 under WS. ABA plus WS improved some of these features from their levels under WS in PBW343. Proline contents were not increased significantly under ABA in both cultivars. Out of ten LEA genes studied, six LEA genes were induced more under WS than under ABA in C306 but equally induced in PBW343. Four LEA genes were induced earlier in PBW343 but later in C306. Wdhn13 was induced more under ABA than under WS in C306 while it was non-responsive to both stresses in PBW343.     

Occurrence of Staphylococcus aureus and evaluation of anti-staphylococcal activity of Lactococcus lactis subsp. lactis in ready-to-eat poultry meat

A total of 181 ready-to-eat poultry meat samples were examined for the presence of Staphylococcus aureus, and 11 (6 %) were found to have S. aureus contamination. Of 11 S. aureus isolates, 10 (91 %) were resistant to at least one antibiotic used in this study, and 2 were resistant to oxacillin. Lactococcus lactis subsp. lactis was tested as a bio-control agent. All the S. aureus isolates were found to be sensitive to antimicrobial products in L. lactis subsp. lactis supernatants; the zones of inhibition were in the range of 5.0 mm?±?0.70 mm to 19.8 mm?±?0.83 mm with the majority of isolates. As a competitive flora in mixed culture (LAPTg broth) and protective culture in poultry meat, L. lactis subsp. lactis was effective against S. aureus isolates; the growth of S. aureus isolates was almost negative after 32 h incubation in mixed culture. The population of S. aureus was reduced substantially to almost log 1 CFU/g after 25 days of incubation in protective culture. The pH of the test cultures also decreased sharply with time.