Clonal propagation of Zephyranthes grandiflora using bulbs as explants

Zephyr lily (Zephyranthes grandiflora), an important ornamental plant has been micropropagated in vitro after controlling microbial contamination by a pretreatment with 0.2 % Bavistin and 0.1 % Pantomycin for 4 h before final sterilization with 0.1 % mercuric chloride. In 67 % of the sterile cultures, 11 shoots on average were regenerated directly from basal half of bulb scales in Murashige and Skoog (MS) medium containing 3 % sucrose and 2 mg dm⁻³ benzylaminopurine (BAP). Shoots emerged in bunches on a basal achlorophyllous bulbous part. Combination of 2 mg dm⁻³ BAP with 1 mg dm⁻³ gibberellic acid (GA₃) enhanced shoot growth. Stout roots (maximum of 5–6 per shoot) were developed in presence of 1 mg dm⁻³ indole-3-butyric acid (IBA). Micro-bulbs showed potential of regeneration and could be used as secondary explants. The morphologically identical plants derived by in vitro propagation were genetically identical as shown by PCR based ISSR marker analysis of genomic DNA.     

Cobalt(III) complexes of some aromatic thiohydrazides - Synthesis, characterization and structure

[Co(NH₃)₅Cl]Cl₂ forms neutral 1:3 complex by reaction with aromatic thiohydrazides, i.e. thiobenzhydrazide, o-hydroxythiobenzhydrazide, thiophen-2-thiohydrazide and furan-2-thiohydrazide. All these complexes are diamagnetic and have been characterized by elemental analysis and combination of spectroscopic methods. Cyclic voltammometry of the complexes shows irreversible metal centered and ligand centered electron transfer reactions. One complex, tris-o-hydroxythiobenzhydrazidocobalt(III), has been crystallized from DMSO solution to produce solvated crystals and its structure has been established by X-ray crystallography. Cobalt(III) ion is linked through three hydrazinic nitrogen and three sulfur atoms of three identical deprotonated ligand molecules in a distorted octahedral environment. Involvement of -OH group in intramolecular and intermolecular hydrogen bonding is crucial for crystal formation.     

Expression of antigens in virulent and avirulent Indian strains ofLeishmania donovani

Indo-Gen mediated surface labelling with¹²⁵I demonstrated differences in surface oriented antigens between virulent and virulent promastigote ofLeishniania donovani, In case of virulent strains, surface polypeptides with molecular masses of 63, 53, 42 and 38 kDa were found to be labelled with¹²⁵I whereas in the case of aviralent stains 68, 55, 50, 46, 42 and 33 Da, components were iodinated. Further studies by immunoblot assay using different subcellular fractions of virulent and avirulent parasites demonstrated that antibody raised against gp63 cross-reacted with the 63 and 60 kDa antigen of the virulent and avirulentLeishmania donovani strains of Indian origin respectively. It indicates that these two polypeptides are antigenically similar. When virulent and avirulent cells were grown in the presence of varying concentration of tunicarnycin and immunoblot with anti gp63, it was observed that with increasing concentration of tunicamycin the 63 kDa polypeptide of the virulent cells shifted to approximately 58–57 kDa and the 60 kDa polypoptide of the aviruleni cells shifted to 57 kDa. This suggests that glycosylation may play an important role in antigenic variation between virulent and avirulent parasites.     

Identification of T-cell receptor V β deletion mutant mouse strain AU/ssJ (H-2 q ) which is resistant to collagen-induced arthritis

Our laboratory is involved in investigating the role of T-cell receptor (Tcr) in collagen-induced arthritis (CIA). During these studies we found AU/ssJ (H-2 ^q ) mice to be resistant to CIA like SWR (H-2 ^q ), as compared with other H-2 ^q strains with wild-type Tcr like DBA/1 and B 10. Q. Upon screening with monoclonal antibodies F23.1 and KJ23a, AU/ssJ was found to be F23.1 negative (V 8 Tcr negative) and KJ23a positive (V 17a Tcr positive). Southern blot analysis on liver DNA using specific Tcr-V probes confirmed the deletion of V 8 gene family and also showed that AU/ssJ mice have deletions of V 9, V 13, V 12, and V 11 genes of Tcr. Further, these mice show a restriction fragment length polymorphism pattern with V 10, V 6, and V 17 probes similar to SWR mice as compared with 1310 mice. Since SWR and AU/ssJ are from different backgrounds, these studies indicate that specific variable region chain genes of Tcr are crucial for susceptibility to CIA in mice. Furthermore, these studies identify an additional inbred strain which has also deleted 50% of its Tcr-V genes.     

Hairy root culture of <Emphasis Type="Italic">Plumbago indica</Emphasis> as a potential source for plumbagin

Hairy roots of Plumbago indica were established at high frequency (90 %) by infecting leaf explants with Agrobacterium rhizogenes strain ATCC 15834. The axenic root cultures were established under darkness in hormone-free liquid Murashige and Skoog medium containing 3 % sucrose. The highest plumbagin content was found to accumulate in roots at their exponential phase of growth. A low pH (4.6) and a low concentration of sucrose (1 %) were beneficial for root growth in darkness, while pH 5.6 and 3 % sucrose under continuous irradiance enhanced plumbagin accumulation in roots up to 7.8 mg g⁻¹(d.m.). Direct shoot regeneration from hairy root culture was also achieved under continuous irradiance, thus indicated an easy way of obtaining transformed P. indica plants.     

An ergonomic study on teenage girls working in the manual brick manufacturing units in the unorganized sectors in West Bengal, India

There are laws which protect and prevent the teenage girls from working. But still in the developing countries like India, Bangladesh, etc. teenage girls coming from low socio-economic background work, to add to the family income. There is dearth of data regarding the ergonomic studies of the teenage girls working in the manual brick manufacturing units of the unorganized sectors in India. Therefore, a field study was conducted in about four brick manufacturing units of West Bengal, India. Their job in these fields was to carry 8-10 unbaked and sun-dried bricks (49.11 +/- 2.13 Kg) from the brick field to the kiln-top and again carry the baked bricks back from the kiln to some other corner of the brick field, under the hot sun. Thus, this study aimed at evaluating their work load and their consequent work-related health effects. Results show that 86 % of them suffered from work-related pain in different body parts and there was an increase in their physiological and psychological parameters after work. It is concluded that the frequent use of awkward postures while at work (OWAS) and performing heavy to moderate types of tasks in the field are deteriorating their health conditions.     

Regeneration of transformed plants from hairy roots of <Emphasis Type="Italic">Plumbago indica</Emphasis>

Spontaneous shoot regeneration was observed from Agrobacterium rhizogenes-induced hairy roots of Plumbago indica when these were incubated in liquid MS medium for a period of 3 weeks under continuous light. Insertion of the rolB gene in putative transformed plants was confirmed by PCR and sequencing. Transformed plants grown for a period of 1 week on solid MS medium containing 0.5 mg l⁻¹ 6-benzyladenine and then transplanted to growth regulator-free medium showed better overall growth than control plants. Transformed plants had a higher root bio-biomass and an increased plumbagin content relative to non-transformed plants.     

In vitro splicing of erythropoietin by the Mycobacterium tuberculosis RecA intein without substituting amino acids at the splice junctions

Protein splicing is a self-catalyzed process involving the excision of an intervening polypeptide sequence, the intein, and joining of the flanking polypeptide sequences, the extein, by a peptide bond. We have studied the in vitro splicing of erythropoietin (EPO) using a truncated form of the Mycobacterium tuberculosis RecA mini-intein in which the homing endonuclease domain was replaced with a hexahistidine sequence (His-tag). The intein was inserted adjacent to cysteine residues to assure that the spliced product had the natural amino acid sequence. When expressed in Escherichia coli, intein-containing EPO was found entirely as inclusion bodies but could be refolded in soluble form in the presence of 0.5 M arginine. Protein splicing of the refolded protein could be induced with a reducing agent such as DTT or tris(2-carboxyethyl)phosphine and led to the formation of EPO and mini-intein along with some cleavage products. Protein splicing mediated by the RecA intein requires the presence of a cysteine residue adjacent to the intein insertion site. We compared the efficiencies of protein splicing adjacent to three of the four cysteine residues of EPO (Cys29, Cys33 and Cys161) and found that insertion of intein adjacent to Cys29 allowed far more efficient protein splicing than insertion adjacent to Cys33 or Cys161. For ease of purification, our experiments involved a His-tagged EPO fusion protein and a His-tagged intein and the spliced products (25 kDa EPO and 24 kDa mini-intein) were identified by Western blotting using anti-EPO and anti-His-tag antibodies and by mass spectroscopy. The optimal splicing yield at Cys29 (40%) occurred at pH 7.0 after refolding at 4 degrees C and splicing for 18 h at 25 degrees C in the presence of 1 mM DTT.