NISCAIR Online Periodicals Repository Collection: IJBB Vol.38(4) [August 2001]

Multiple isoforms of protein kinase C in lymphocytes and airway smooth muscle of guinea pig

Title: Multiple isoforms of protein kinase C in lymphocytes and airway smooth muscle of guinea pig

Authors: Fatma, Sumbul; Mushinski, J Frederic; Bansal, Surendra Kumar

Abstract: The isoenzyme pattern of protein kinase C (PKC) in lymphocytes and airway smooth muscles (ASM) was examined by Wes tern blot using commercially available monoclonal antibodies. The results showed the presence of PKC α, β, γ, ε, η, μ and ζ in lymphocytes and PKC α, γ, ε, η and ζ in ASM. The unexpected feature was the presence of PKC γ in both lymphocytes and ASM of guinea pigs. Expression of this PKC isoform is usually restricted to tissues in the central nervous system or spinal cord. Expression of PKC δ, θ, λ and τ was not detected in either lymphocytes or ASM.

Page(s): 280-284

Determination of antidiabetic activity in Allium cepa (onion) tissue cultures

Title: Determination of antidiabetic activity in Allium cepa (onion) tissue cultures

Authors: Kelkar, S M; Kaklij, G S; Bapat, V A

Abstract: Seedling, seedling parts and callus cultures of onion were tested for their antidiabetic activity by feeding the tissue-extracts to diabetic rats. The results indicated much higher antidiabetic activity in callus cultures as compared to natural bulbs of onion. These results may be of pharmaceutical significance since the callus can be used as an alternative source for the isolation of antidiabetic compounds.

Page(s): 277-279

Purification of tryptic peptides for mass spectrometry using polyvinylidene fluoride Membrane

Title: Purification of tryptic peptides for mass spectrometry using polyvinylidene fluoride Membrane

Authors: Kurien, B T; Matsumoto, H; Scofield, R H

Abstract: A simple procedure for the purification of tryptic peptides, prior to mass spectrometric analysis, using polyvinylidene fluoride membrane (PVDF) is described. The sensitivity of mass spectrometric analysis is such that minor impurities in tryptic peptide digests suppress the signal obtained. However, we obtained useful signal, from a sample that did not yield any spectra earlier, by purifying the sample using PVDF membrane. For this. the tryptic peptide digest was first spotted on the membrane which was then air-dried and washed. Further, the membrane was extracted with trifluoroacetic acid (TFA) and acetonitrile and subjected to mass spectrometric analysis. This procedure enabled us to identify a cross-reactive D1 antigen on the neutrophil surface that bound antibodies that targeted 60 kD Ro autoantigen in systemic lupus erythematosus, an autoimmune disorder.

Page(s): 274-276

Effect of aflatoxin B1 on phosphoinositide signal transduction pathway during regeneration of liver cells following partial hepatectomy

Title: Effect of aflatoxin B1 on phosphoinositide signal transduction pathway during regeneration of liver cells following partial hepatectomy

Authors: Mistry, K J; Krishna, M; Bhattacharya, R K

Abstract: Aflatoxin B₁ (AFB₁) when administered to partially hepatectomised rats 4 hr prior to sacrifice, activated signalling pathway in regenerating rat liver. The activity of phosphatidylinositol (PI) kinase was found decreased at 30 min but increased at 24 hr and returned to normal at 48 hr. At 30 min. inositol-IA,5-triphosphate (IP₃) level increased significantly whereas diacylglycerol (DAG) level dropped. However, at 24 hr and 48 hr, DAG and IP₃ showed the same trend i.e. an increase in their levels. Phosphatidylinositol-4-phosphate levels were found to increase at 24 hr. Protein kinase C (PKC), activity from the particulate fraction was significantly inhibited at 30 min, followed by increase in activity at 24 hr and return to normal at 48 hr. Cytosolic PKC showed a decrease at 24 hr and a significant increase at 48 hr. At the peak of DNA synthesis (24 hr) following partial hepatectomy, all these signalling steps had earlier been found to be inhibited, but the present study shows that aflatoxin B₁ administration 4 hr prior to sacrifice reverses the action. Activation of PKC by aflatoxin B₁ during regeneration of liver cells when PKC in normally inhibited, may possibly create conditions conducive to carcinogenesis.

Page(s): 270-273