Stable NaCl Tolerance of Tobacco Cells Is Associated with Enhanced Accumulation of Osmotin

Osmotin is a major protein which accumulates in tobacco cells (Nicotiana tabacum L. var Wisconsin 38) adapted to low water potentials. Quantitation of osmotin levels by immunoblots indicated that cells adapted to 428 millimolar NaCl contained 4 to 30 times the level of osmotin found in unadapted cells, depending on the stage of growth. Unadapted cells accumulated low levels of osmotin with apparent isoelectric points, (pl) of 7.8 and >8.2. Upon transfer of NaCl-adapted cells to medium without NaCl and subsequent growth for many cell generations, the amount of osmotin declined gradually to a level intermediate between that found in adapted and unadapted cells. NaCl-adapted cells grown in the absence of NaCl accumulated both pl forms; however, the form accumulated by cells adapted to NaCl (pl > 8.2) was most abundant. Adapted cells grown in the absence of NaCl exhibited absolute growth rates and NaCl tolerance levels which were intermediate to those of NaCl-adapted and unadapted cells. The association between osmotin accumulation and stable NaCl tolerance indicates that cells with a stable genetic change affecting the accumulation of osmotin are selected during prolonged exposure to high levels of NaCl. This stable alteration in gene expression probably affects salt tolerance.

Kala-azar mortality in hospitalized cases in north Bihar, India

The mortality in kala-azar was studied in 261 cases admitted in SKMCH during the years 1983-1987. 23 deaths (8.81%) were observed; 9 (39.1%) died due to complications of the disease, while 14 (60.9%) died of toxicity of Sodium Stibogluconate or Pentamidine.

Molecular Cloning of Osmotin and Regulation of Its Expression by ABA and Adaptation to Low Water Potential

In response to adaptation to NaCl, cultured tobacco cells (Nicotiana tabacum L. cv Wisconsin 38) synthesize a major 26 kilodalton protein which has been named osmotin due to its induction by low water potentials. To help characterize the expression of osmotin in adapted cells, a cDNA clone for osmotin has been isolated. Abscisic acid induces messenger RNA encoding osmotin. Levels of this mRNA in adapted cells are approximately 15-fold higher than in unadapted cells. Message for osmotin is present at constant levels through the growth cycle of adapted cells, while in unadapted cells, the level decreases during exponential phase of growth and increases again when the cells approach stationary phase. While abscisic acid induces the message for osmotin, a low water potential environment appears to be required for accumulation of the protein. An osmotic shock to unadapted cells does not increase the amount of message or protein present most likely because this treatment does not induce immediately the accumulation of abscisic acid. The increased expression of osmotin in adapted cells is not correlated with an increase in osmotin gene copy number. Osmotin is homologous to a 24 kilodalton NaCl-induced protein in tomato, as well as thaumatin, maize alpha-amylase/trypsin inhibitor and a tobacco mosaic virus-induced pathogenesis-related protein.

Visceral kala-azar associated with post-kala-azar dermal leishmaniasis

Visceral leishmaniasis associated with post-kala-azar dermal leishmaniasis (PKDL) is very rare. We are reporting one such case which incidentally is the seventh case so far reported from Indian sub-continent.

Persistent hyperglycaemia requiring insulin therapy following the use of pentamidine in the treatment of kala-azar

Five cases of persistent hyperglycaemia requiring insulin therapy following pentamidine treatment for Indian kala-azar are being reported.

The cumulative effect of allelic variation in LMW and HMW glutenin subunits on dough properties in the progeny of two bread wheats

The effects of allelic variation at Gli-A1, GluA3 and Glu-A1 loci coding for gliadins, LMW glutenin subunits and HMW glutenin subunits on dough resistance and extensibility was analysed in 56 F2-derived F6 families from a cross between bread wheats MKR(111/8) and 'Kite'. Extensograph data from two sites giving widely different flour protein levels (approximately 7% and 14%) revealed that the Glu-A3m and Glu-A1b alleles were associated with larger effects on dough resistance and extensibility than the null alleles Glu-A3k and GluA1c, respectively, and moreover, their effects were additive at both protein levels. The effect of the LMW glutenin allele Glu-A3m on both dough resistance and dough extensibility was relatively larger than that of the HMW glutenin allele Glu-A1b at both sites. Variation at the Gli-A1 locus did not appear to contribute towards dough strength. The results also showed the large effect of flour protein content on dough properties.

Identification of legumin-like proteins in wheat

We have obtained several amino acid sequences from purified polypeptides of a wheat endosperm storage globulin previously described as 'triplet' protein. The amino acid sequence data supported by immunochemical analysis using anti-oat 12S globulin antibodies, provide definitive evidence that the triplet protein is homologous to pea legumin and related seed storage proteins of oats, rice and several dicotyledonous species. Thus, it is now proposed that the triplet protein of wheat be renamed 'triticin'. The oat globulin antibodies also cross-reacted strongly with the high-molecular-weight (HMW) glutenin subunits which have been implicated in bread-making quality.

Characterization of osmotin : a thaumatin-like protein associated with osmotic adaptation in plant cells

Cultured tobacco (Nicotiana tabacum var Wisconsin 38) cells adapted to grow under osmotic stress synthesize and accumulate a 26 kilodalton protein (osmotin) which can constitute as much as 12% of total cellular protein. In cells adapted to NaCl, osmotin occurs in two forms: an aqueous soluble form (osmotin-I) and a detergent soluble form (osmotin II) in the approximate ratio of 2:3. Osmotin-I has been purified to electrophoretic homogeneity, and osmotin-II has been purified to 90% electrophoretic homogeneity. The N-terminal amino acid sequences of osmotins I and II are identical through position 22. Osmotin-II appears to be much more resistant to proteolysis than osmotin-I. However, it cross-reacts with polyclonal antibodies raised in rabbits against osmotin-I. Osmotin strongly resembles the sweet protein thaumatin in its molecular weight, amino acid composition, N-terminal sequence, and the presence of a signal peptide on the precursor protein. Thaumatin does not cross-react with antiosmotin. An osmotin solution could not be detected as sweet at a concentration at least 100 times that of thaumatin which could be detected as sweet. Immunocytochemical detection of osmotin revealed that osmotin is concentrated in dense inclusion bodies within the vacuole. Although antiosmotin did not label organelles, cell walls, or membranes, osmotin appeared sparsely distributed in the cytoplasm.

Nonenzymatic synthesis of delta-aminolevulinate (ALA) by cobalt (Co++)

Cobalt, a metal known to modulate the heme biosynthetic enzymes, is shown to be capable of catalysing the formation of ALA through a transamination reaction. The transamination reaction follows a double-displacement reaction kinetics. Further, it has also been shown that the product of the reaction catalysed by cobalt can be used by the enzyme ALA dehydratase as the substrate in the formation of porphobilinogen. The formation of ALA by cobalt can be inhibited by the intermediates of the heme biosynthetic pathway, mainly protoporphyrin. Heme, on the other hand, does not have any effect on the reaction at all concentrations tested.

Assessment of autonomic dysfunction in Guillain-Barré syndrome and its prognostic implications

Twenty-four patients with Guillain-Barré syndrome were prospectively evaluated for evidence of autonomic dysfunction. It occurred in 16 (66.7%) patients, usually during the peak period of paralysis, in the form of either excess or inadequate activity of sympathetic and/or parasympathetic nervous systems. Its clinical manifestations comprised of sinus tachycardia (33.3%), bradycardia (8.3%), hypertension (33.3%), postural hypotension (35%), urinary sphincteric disturbances (20.8%) and anhydrosis of lower limbs (12.5%). Assessment of cardiovascular responses to autonomic function tests revealed impaired alterations in heart rate during deep breathing (31.6%), Valsalva's manoeuvre (28.6%), sustained handgrip (25%), cold-pressor test (36.4%), postural change (35%) and atropine test (20%); and impaired rise in blood pressure during firm handgrip (25%) and cold-pressor test (36.6%). ECG abnormalities were noticed in 8 (33.3%) patients. They comprised of depressed ST segment in 5, inverted T wave in 3, tall T wave in 2 and prolonged QTc in 2 patients. Two patients died of respiratory failure. Autonomic dysfunction in Guillain-Barré syndrome did not appear to have any prognostic significance as there was no significant difference in autonomic dysfunction between good - and bad - outcome groups of patients.

Induction of L-alanine:4,5-dioxovalerate transaminase by phenylhydrazine is associated with depletion of heme level

The hemin regulation of L-alanine:4,5-dioxovalerate transaminase, the enzyme proposed for an alternate route of delta-aminolevulinic acid (ALA) biosynthesis in mammalian system was studied in different conditions: phenylhydrazine induced anemia, polycythemia by erythropoietin to anemic rats, treatment with cobalt chloride, a porphyrogenic drug. The activity of L- alanine:4,5-dioxovalerate transaminase in liver and kidney is stimulated in phenylhydrazine, whereas, erythropoietin injection to anemic rats prevents such stimulation. Further treatment with cobalt chloride to erythropoietin treated anemic rats stimulates the enzyme activity. Actinomycin D, however, inhibits the stimulation of L-alanine:4,5-dioxovalerate transaminase by phenylhydrazine suggesting that induction is at the level of transcription. Induced level of this enzyme in anemic condition was estimated quantitatively by radial immunodiffusion using antibody raised against L-alanine:4,5-dioxovalerate transaminase. Moreover, our studies reveal that stimulation of L-alanine:4,5-dioxovalerate transaminase in anemic condition is dependent on depletion of heme level. The regulatory role of intracellular heme pool on the induction of this enzyme suggests its physiological importance in heme biosynthesis.

Muscle dysfunction in male hypogonadism

Twenty-eight consecutive male patients with primary and secondary hypogonadism (14 each) were evaluated clinically and electrophysiologically for muscle dysfunction. Although generalised muscle weakness was initially reported by only 9 patients, on direct questioning, it was recorded in 19. Objective weakness was found in 13 patients and it involved both the proximal and distal limb muscles. Quantitative electromyography showed evidence of myopathy in the proximal muscle in 25 patients, i.e., reduced MUP duration and amplitude with increased polyphasia in the deltoid and the gluteus maximus. There were no denervation potentials. None of the patients showed clinical neuropathy or NCV abnormalities. Thus, the profile of muscle involvement in hypogonadism closely simulates limb-girdle muscular dystrophy and other endocrine myopathies. The incidence of muscle involvement was higher in secondary hypogonadism. Diminished androgens in primary hypogonadism and diminished growth hormone in the secondary hypogonadism are probably responsible for the myopathy.