Effective Protocol for in Vitro Shoot Production Through Nodal Explants of Simmondsia Chinensis

Nodal explants excised from 18 to 20-year-old female plants of Simmondsia chinensis if cultured on Murashige and Skoog's medium supplemented with 20 M N⁶-benzyladenine (BA) differentiated an average of 2.7 ± 0.4 shoots in 11.5% explants. The percentage of nodal explants inducing multiple shoots enhanced significantly if in vitro raised shoots were used as source of explants. Nearly 100% cultures differentiated an average of 4.7 ± 2.0 shoots per explant on the same medium. Nearly 85% of the shoots induced roots when a pulse treatment of 50 M indole-3-butyric acid (IBA) was given prior to their transfer to semi-solid MS medium containing 10 M IBA + 0.5% activated charcoal + 1 M BA. Plantlets were gradually hardened in Soilrite and acclimatized to soil.     

Transition metal complexes of buparvaquone as potent new antimalarial agents. 1. Synthesis,X-ray crystal-structures,electrochemistry and antimalarial activity against Plasmodium falciparum

New Cu(II), Ni(II), Co(II), Fe(II), and Mn(II) metal complexes of buparvaquone [3-trans(4-tert.-butylcyclohexyl)methyl-2-hydroxy-1,4-naphthoquione] (L1H) have been synthesized and characterized using IR, electron paramagnetic resonance (EPR) spectroscopy, microanalytical methods and single crystal X-ray diffraction methods. The single crystal structures were determined for ligand L1H [space group P-1 with a=6.2072(14) A, b=10.379 (2) A, c=13.840 (3) A, V=878.7(3) A(3), Z=2, D(calcd.)=1.234 mg/m(3)] and copper complex [Cu(L1)(2)(C(2)H(5)OH)(2)] C1 [space group I2/a with a=17.149(14) A, b=9.4492(8) A, c=26.946(3) A, V=4335.3(7)A(3), Z=4, D(calcd.)=1.233 mg/m(3)]. All the metal complexes along with the parent ligand have been studied for their electrochemical properties using cyclic voltammetric techniques. The compounds were tested for their in vitro antimalarial activity against Plasmodium falciparum strains. A correlation between the antimalarial activity and the redox property of these complexes is presented. The copper complex C1 exhibits significantly higher growth inhibitory activity both in vitro and in vivo than the parent ligand.     

Cloning, expression, activity and folding studies of serine hydroxymethyltransferase: a target enzyme for cancer chemotherapy

All the members of pyridoxal-5'-phosphate-dependent enzymes are involved in the metabolism of amino acids. The sequence homology studies further divide this family into three distinct groups. A fine scrutiny of the reactions catalyzed by these enzymes shows their regio specificity; they have been considered as the largest group of enzymes having tendency to affect the valency of the same carbon atom that carries the amino group forming an amine linkage with the coenzyme. Thus, this group was named 'alpha-class of enzymes'. Serine hydroxymethyltransferase (SHMT) is a member of this alpha-class; it reversibly catalyses the conversion of serine into glycine while the hydroxymethyl group is transferred to 5,6,7,8-tetrahydrofolate. The resultant compound is the sole precursor of purine biosynthesis. Henceforth, this enzyme greatly affects nucleic acid biosynthesis in all the organisms. It is obvious that SHMT plays an indispensable role in nucleic acid biosynthesis; therefore, designing and developing a repressor/inhibitor of the SHMT gene/protein may resolve the problem of drug resistance to cancer chemotherapy. SHMT has been widely studied in many living systems (e.g. Escherichia coli, humans, sheep, rabbits, Trypanosoma, Arabidopsis, peas, tobacco) in terms of its structure, cloning, expression, purification and folding patterns. Such studies have enabled one to assess the pattern of overall kinetic and activity behaviour of the enzyme, which may further help in developing a suitable cancer therapeutic molecule.     

Neuron and glia generating progenitors of the mammalian enteric nervous system isolated from foetal and postnatal gut cultures

Cultures of dissociated foetal and postnatal mouse gut gave rise to neurosphere-like bodies, which contained large numbers of mature neurons and glial cells. In addition to differentiated cells, neurosphere-like bodies included proliferating progenitors which, when cultured at clonal densities, gave rise to colonies containing many of the neuronal subtypes and glial cells present in the mammalian enteric nervous system. These progenitors were also capable of colonising wild-type and aganglionic gut in organ culture and had the potential to generate differentiated progeny that localised within the intrinsic ganglionic plexus. Similar progenitors were also derived from the normoganglionic small intestine of mice with colonic aganglionosis. Our findings establish the feasibility of expanding and isolating early progenitors of the enteric nervous system based on their ability to form distinct neurogenic and gliogenic structures in culture. Furthermore, these experiments provide the rationale for the development of novel approaches to the treatment of congenital megacolon (Hirschsprung's disease) based on the colonisation of the aganglionic gut with progenitors derived from normoganglionic bowel segments.     

Production of xylanase by Emericella nidulans NK-62 on low-value lignocellulosic substrates

Thermotolerant Emericella nidulans NK-62 was isolated from bird nesting material and was tested for its ability to produce xylanase. The fungus when grown on a medium containing wheat bran (2% w/v) supplemented with Czapek's mineral salt solution at 45 °C for 7 days produced 362 IU/ml of xylanase (EC 3.2.1.8). The specific activity of E. nidulans NK-62 xylanase was found to be 275 IU/mg of total protein. The enzyme was found to be active over a broad temperature and pH range with 60 °C as optimum temperature for enzyme activity. The enzyme was stable at 50 °C and its half-life at 55 °C was 45 min. -xylosidase (EC 3.2.1.37) and carboxymethylcellulase (EC 3.2.1.4) activities, 0.018 and 0.21 IU/ml respectively, were also noticed. The fungus was screened for its ability to produce xylanase on four different lignocellulosic substrates. It produced 318.9 IU/ml of cellulase-free xylanase on corn cobs. The fungus could also utilize lentil bran (seed husk of Lens esculentus) and meal of groundnut shells to produce 84.8 and 17.3 IU/ml xylanase respectively.     

Movement of the decoding region of the 16 S ribosomal RNA accompanies tRNA translocation

The ribosome undergoes pronounced periodic conformational changes during protein synthesis. Of particular importance are those occurring around the decoding site, the region of the 16 S rRNA interacting with the mRNA-(tRNA)(2) complex. We have incorporated structural information from X-ray crystallography and nuclear magnetic resonance into cryo-electron microscopic maps of ribosomal complexes designed to capture structural changes at the translocation step of the polypeptide elongation cycle. The A-site region of the decoding site actively participates in the translocation of the tRNA from the A to the P-site upon GTP hydrolysis by elongation factor G, shifting approximately 8 A toward the P-site. This implies that elongation factor G actively pushes both the decoding site and the mRNA/tRNA complex during translocation.     

Quantitative proteomics of Arabidopsis shoot microsomal proteins reveals a cross‐talk between excess zinc and iron deficiency

Iron (Fe) deficiency significantly effects plant growth and development. Plant symptoms under excess zinc (Zn) resemble symptoms of Fe‐deficient plants. To understand cross‐talk between excess Zn and Fe deficiency, we investigated physiological parameters of Arabidopsis plants and applied iTRAQ‐OFFGEL quantitative proteomic approach to examine protein expression changes in microsomal fraction from Arabidopsis shoots under those physiological conditions. Arabidopsis plants manifested shoot inhibition and chlorosis symptoms when grown on Fe‐deficient media compared to basal MGRL solid medium. iTRAQ‐OFFGEL approach identified 909 differentially expressed proteins common to all three biological replicates; the majority were transporters or proteins involved in photosynthesis, and ribosomal proteins. Interestingly, protein expression changes between excess Zn and Fe deficiency showed similar pattern. Further, the changes due to excess Zn were dramatically restored by the addition of Fe. To obtain biological insight into Zn and Fe cross‐talk, we focused on transporters, where STP4 and STP13 sugar transporters were predominantly expressed and responsive to Fe‐deficient conditions. Plants grown on Fe‐deficient conditions showed significantly increased level of sugars. These results suggest that Fe deficiency might lead to the disruption of sugar synthesis and utilization.