Arbuscular mycorrhizas in cycads of southern India

Root and soil samples of three potted or ground-grown cycads ( Cycas circinalis, C. revoluta, Zamiasp.) were collected between November 1999 and June 2000 and surveyed for arbuscular mycorrhizal (AM) colonization and spore populations. AM fungi were associated with all root systems and rhizosphere samples examined. Root colonization was of a typical Arum type and AM colonization levels differed significantly between species and between potted and ground-grown cycads. Mycorrhizal colonization levels were inversely related to root hair number and length. Spores of nine morphotypes belonging to three genera ( Acaulospora, Glomus, Scutellospora) were extracted from soil. The percentage root length colonized by AM fungi was not related to soil factors, but total AM fungal spore numbers in the rhizosphere soil were inversely related to soil nitrogen and phosphorus levels. AM fungal spore numbers in the soil were linearly related to root length colonized. The co-occurrence of septate non-mycorrhizal fungi was recorded for the first time in cycads. These observations and the relationship between plant mycorrhizal status and soil nutrients are discussed.     

Molecular modelling of urease accessory interaction proteins of Helicobacter Pylori J 99 and predicting an interruption in interaction by Vigna radiata Defensins

Helicobacter pylori is the major causative agent of Gastric carcinoma. Significance of the urease accessory interaction proteins are emphasized in colonization of human gastric mucosa and efficient infection of H. pylori. Here an attempt is made to explore the structure and properties of urease accessory interaction proteins from Helicobacter pylori J 99. The proteins chosen for the study are ureH, ureI, nikR, groL and flgS based on the interaction map available from STRING database. The above mentioned proteins do not have a comprehensive three dimensional structure. Hence the models were generated using PSI-BLAST (Position Specific Iterative-Blast) and MODELLER 9V8. Physicochemical characterization encompasses pI, EC, AI, II and GRAVY. Secondary structure was predicted using PSI-PRED. Functional characterization was done by SOSUI and DISULFIND Servers and refinement of structure was done using Ramachandran plot analysis. RMS-Z values were calculated using Q-MEAN Server and CHIMERA was used for molecular simulation studies. Plant defensins from Vigna radiata are successfully docked to the modeled structures and thus interaction could be possibly prevented. These results will pave way for further selective inhibition of H. pylori colonization and in vivo survival by employing plant defensins from Vigna radiata (VrD1 & VrD2). The work will prove that plant defensins provides anticancer relief too.     

Occurrence of alfalfa (<Emphasis Type="Italic">Medicago sativa</Emphasis> L.) populations along roadsides in southern Manitoba,Canada and their potential role in intraspecific gene flow

Alfalfa is a highly outcrossing perennial species that can be noticed in roadsides as feral populations. There remains little information available on the extent of feral alfalfa populations in western Canadian prairies and their role in gene flow. The main objectives of this study were (a) to document the occurrence of feral alfalfa populations, and (b) to estimate the levels of outcrossing facilitated by feral populations. A roadside survey confirmed widespread occurrence of feral alfalfa populations, particularly in alfalfa growing regions. The feral populations were dynamic and their frequency ranged from 0.2 to 1.7 populations km⁻¹. In many cases, the nearest feral alfalfa population from alfalfa production field was located within a distance sufficient for outcrossing in alfalfa. The gene flow study confirmed that genes can move back and forth between feral and cultivated alfalfa populations. In this study, the estimated outcrossing levels were 62% (seed fields to feral), 78% (feral to seed fields), 82% (hay fields to feral) and 85% (feral to feral). Overall, the results show that feral alfalfa plants are prevalent in alfalfa producing regions in western Canada and they can serve as bridges for gene flow at landscape level. Management of feral populations should be considered, if gene flow is a concern. Emphasis on preventing seed spill/escapes and intentional roadside planting of alfalfa cultivars will be particularly helpful. Further, realistic and pragmatic threshold levels should be established for markets sensitive to the presence of GE traits.     

Transport of Phosphatidylserine from the Endoplasmic Reticulum to the Site of Phosphatidylserine Decarboxylase2 in Yeast

Over the past two decades, most of the genes specifying lipid synthesis and metabolism in yeast have been identified and characterized. Several of these biosynthetic genes and their encoded enzymes have provided valuable tools for the genetic and biochemical dissection of interorganelle lipid transport processes in yeast. One such pathway involves the synthesis of phosphatidylserine (PtdSer) in the endoplasmic reticulum (ER), and its non‐vesicular transport to the site of phosphatidylserine decarboxylase2 (Psd2p) in membranes of the Golgi and endosomal sorting system. In this review, we summarize the identification and characterization of the yeast phosphatidylserine decarboxylases, and examine their role in studies of the transport‐dependent pathways of de novo synthesis of phosphatidylethanolamine (PtdEtn). The emerging picture of the Psd2p‐specific transport pathway is one in which the enzyme and its non‐catalytic N‐terminal domains act as a hub to nucleate the assembly of a multiprotein complex, which facilitates PtdSer transport at membrane contact sites between the ER and Golgi/endosome membranes. After transport to the catalytic site of Psd2p, PtdSer is decarboxylated to form PtdEtn, which is disseminated throughout the cell to support the structural and functional needs of multiple membranes.      

Developmental stages and secondary compound biosynthesis of mycobiont and whole thallus cultures of <Emphasis Type="Italic">Buellia subsororioides</Emphasis>

Lichen species have unique culture media preferences, and established cultures are known for the synthesis of secondary metabolites. This paper reports observations on the developmental stages and secondary compound biosynthesis by the mycobiont and whole thallus cultures of Buellia subsororioides. It also investigates the suitable media compositions for the culture growth, the role (nutrient or stressor) of sucrose concentrations on the growth stages, biomass, secondary compound profiles, and the quantity of biosynthesized known compounds/g of culture biomass for each treatment using mycobiont cultures. The ascospore-derived mycobiont cultures and thallus macerate-derived whole thallus cultures of B. subsororioides were established and grown using malt yeast extract (MY) medium. Mycobiont cultures were subcultured in MY medium supplemented with sucrose and its concentrations ranging from 0 to 30 % (with 2 % increment between treatments) for 120 days. The molecular identity of cultures was confirmed using nuclear ribosomal Internal transcribed spacer (ITS) DNA sequences obtained from the cultured mycobiont and from the natural thallus. The ITS DNA sequences of the mycobiont showed 99 % similarity with the sequences of the natural thallus. The mycobiont cultures under varying sucrose concentrations initiated as white cottony stages and transformed to brown compact mycelia, with optimum biomass and biosynthesis of nine secondary compounds in MY 10 %. The number of compounds (1–9) varies according to treatments. The whole thallus cultures (MY 0 %) showed a profile of secondary compounds similar to that of the natural thalli along with a trace of one unknown compound. The obtained results are encouraging for the synthesis of the desired quantities of lichen secondary compounds through cultures for relevant applications.     

Ultrasound assisted green synthesis of silver nanoparticles using weed plant

This study presents the facile, green and eco-friendly synthesis of silver nanoparticles (AgNPs) using weed plant Lantana camara L. leaf extract. The incorporation of ultrasound into this reduced the time and increased the reaction rate. The results showed that the AgNPs were spherical in shape with the average size of 33.8 nm. The EDAX pattern indicated the presence of abundant silver and XRD indicated that the (111) crystallographic plane more predominant than other planes. The possible functional groups responsible for the reduction and stabilization of AgNPs were identified using Fourier transform infrared spectroscope. The XPS results concluded that the nanoparticles were presented in its reduced metallic state. The antioxidant activity of AgNPs was assayed using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) test. The increase in the concentration of AgNPs increased the DPPH scavenging activity. The AgNPs revealed superior antibacterial activity against Gram positive and Gram negative organisms.     

The ubiquitin-interacting motifs of S5a as a unique upstream inhibitor of the 26S proteasome

It has been demonstrated that ubiquitin-conjugated proteins were accumulated by ectopically-expressed S5a as well as the ubiquitin-interacting motifs of S5a (S5a-UIMs). In this study, we further found that free S5a-UIMs stabilized only a subset of proteasomal substrates including p53, c-Fos, c-Jun, and p27 but not β-catenin, p15, and ornithine decarboxylase. Both S5a-UIMs and epoxomicin inhibited the proliferation of A549 lung cancer cells but arrest at the different stages of cell cycle. Together, our results suggest a potential role of S5a-UIMs as an upstream proteasomal inhibitor by blocking the subset of substrates from delivery to the 26S proteasome.     

Bacillus sp. mutant for improved biodegradation of Congo red: Random mutagenesis approach

This study presents the improved biodegradation of Congo red, a toxic azo dye, using mutant Bacillus sp. obtained by random mutagenesis of wild Bacillus sp. using UV and ethidium bromide. The mutants obtained were screened based on their decolorization performance and best mutants were selected for further studies. Better decolorization was observed in the initial Congo red concentration range 100–1000 mg/l for wild species whereas mutant strain was found to offer better decolorization up to 3000 mg/l. Mutant strain offered 12–30% reduction in time required for the complete decolorization by wild strain. The optimum pH and temperature were found to be 7.0 and 37 °C, respectively. Two efficient strains such as Bacillus sp. ACT 1 and Bacillus sp. ACT 2 were isolated from the various mutants obtained. Bacillus sp. ACT 2 showed improved enzymatic production and Bacillus sp. ACT 1 showed improved growth compared to wild strain. The enzyme responsible for the degradation was found to be azoreductase by SDS–PAGE and about 53% increased production of enzyme was achieved with mutant species. The experimental data were modeled using growth and substrate inhibition models.