Ficus cunia agglutinin for recognition of bacteria.

Interaction of bacteria with lectin using anti-lectin antibody by ELISA is an established method. In the present study, we have devised a simple ELISA using a biotinylated lectin and antibiotin-HRP. Ficus cunia agglutinin (FCA), which has shown the specificity towards alpha/beta anomers of GlcNAc and other-NAc containing sugars like LacNAc and GlcNAcbeta(1-4/6)GlcNAc, was used as a model lectin for the study of interaction with immobilized microorganisms on ELISA plate. The bacterial cells of E. coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Bacillus subtilis and Staphylococcus aureus showed binding with FCA and the degree of binding was dependent on the bacterial surface antigen. This method is considered a simple technique to study the lectin-bacteria interaction.

Heart rate variability in dilated cardiomyopathy.

Chronic heart failure is associated with excessive neurohormonal activation. Analysis of heart rate variability is considered a valid technique for assessment of the autonomic balance of the heart. Twenty symptomatic patients of dilated cardiomyopathy in NYHA class II-IV symptomatic status and as many normal controls were subjected to 24 hours Holter monitoring to assess the heart rate variability with both time domain and frequency domain analysis. Age of the patients ranged from 12 to 67 years (mean +/- SD 38.6 +/- 7 years), the male-female ratio was 4:1. The left ventricular ejection fraction of the patients was between 18-42 percent (mean +/- SD 30.2 +/- 9%) and all received diuretics, digoxin and angiotensin-converting enzyme inhibitors. Heart rate variability parameters measured included mean heart rate with standard deviation, hourly heart rate with SD and the mean of all normal RR intervals from the 24-hour recording. Time domain measures calculated were SD of all normal RR intervals, SD of 5 minute mean RR intervals and root mean square of difference of successive RR intervals. Using spectral plots, frequency domain subsets of low frequency and high frequency were analysed and expressed in normalised units. Total power was also measured. In the dilated cardiomyopathy patients, mean 24-hour heart rate in beats per minute was significantly higher in comparison to controls (82 +/- 13 vs 72 +/- 8; p < 0.001) whereas mean hourly heart rate with standard deviation (msec) was significantly lower (97 +/- 41 vs 232 +/- 25; p < 0.001), SD of all normal RR intervals (msec) was 85.5 +/- 26.3 vs 139.4 +/- 16.9 in controls (p < 0.001), SD of 5 minute mean RR intervals (msec) was also significantly less in patients in comparison to controls (75.8 +/- 39.6 vs 130.8 +/- 20.3; p < 0.001). However, although root mean square of difference of successive RR intervals (msec) was reduced in patients (30.1 +/- 9.3 vs 37.3 +/- 11.7; p < 0.05), the difference was non-significant. Low frequency power (0.05-0.15 Hz) (normalised units) was reduced in the dilated cardiomyopathy group (0.0721 +/- 0.003 vs 0.136 +/- 0.047 in the control group; p < 0.001). High frequency power (0.35-0.50 Hz) (normalised units) (0.08 +/- 0.05 in patients vs 0.09 +/- 0.02 in controls; p > 0.1) and total power frequency (0.02-0.50 Hz) (normalised units) (0.34 +/- 0.05 in patients vs 0.35 +/- 0.12 in controls; p > 0.1) was non-significantly different in the two groups. Regression analysis showed a significant decrease in SD of all normal RR intervals, SD of 5 minute mean RR intervals, low frequency, high frequency, total power and a non-significant decrease in root mean square of difference of successive RR intervals with a decrease in ejection fraction percent whereas there was a significant decrease in SD of all normal RR intervals, SD of 5 minute mean RR intervals, low frequency and total power and a less significant decrease in root mean square of difference of successive RR intervals and high frequency power with an increase in NYHA class. At 6 months duration, 6 patients were lost to follow-up, 3 patients were readmitted (2 for congestive cardiac failure, one of paroxysmal supraventricular tachycardia). One patient who was NYHA class IV at baseline was readmitted for congestive cardiac failure and showed much lower heart rate variability parameters compared to the average of the patients. We conclude that in symptomatic dilated cardiomyopathy patients, heart rate variability parameters are significantly reduced in comparison to control subjects.

Inhibition of bacterial respiration by a low-molecular weight lectin, scyllin, from Scylla serrata crab hemolymph.

Interaction of plant and/or invertebrate lectins with mammalian cells and different microorganisms is well known. In the present study, we have demonstrated that scyllin, a low molecular weight (MW 4000) lectin from the edible crab Scylla serrata hemolymph, purified by GalNAc-Sepharon affinity column followed by Mono-Q ion exchanger in FPLC exhibits antimicrobial activity against Bacillus cereus and Escherichia coli by inhibiting endogenous respiration as well as exogenous glucose oxidation. In both the cases oxygen consumption has been measured in an oxygraph. Scyllin has produced 50% inhibition of endogenous respiration at a concentration of 110 micrograms/ml and 125 micrograms/ml in B. cereus and E. coli respectively. It also reduced the exogenous glucose oxidation by 50% at a concentration of 12 micrograms/ml and 80 micrograms/ml respectively in B. cereus and E. coli. From the above study the mechanism of bacterial growth inhibitory property of scyllin is suggested though the other studies such as inhibition of nucleic acid biosynthesis, cell wall biosynthesis etc. to evaluate its total mode of inhibitory action are not yet obtained.

Cocos nucifera pollen inducing allergy: sensitivity test and immunological study.

Among the heterogeneous population (n = 975) in greater Calutta, sensitization to Cocos nucifera pollen accounts to be 2.65% and for atopic patients (n = 204) 47.06%. Out of 24 patients who had C. nucifera pollen sensitivity and suffered from asthma and allergic rhinitis, 16 showed sensitivity also to other allergens. All were skin test positive and 19 of them were phadezym RAST positive to C. nucifera pollen extract. Bronchial provocation test appeared to be positive in 7 out of 8 patients included in the test and no late response or non-specific reactions were observed. C. nucifera pollen extract on fractionation by ion-exchange chromatography following gel filtration yielded two major allergenic protein fractions, CnII (M(r) 158,000) and CnVII (M(r) 2900) as evidenced by skin prick test, ELISA-inhibition and immunoblot analysis. Hence, C. nucifera pollen should be considered to be a relevant allergen and thus included in the panel of allergens for routine clinical use.

Studies on the effect of various parameters on crotalarin-fetuin interaction.

With a view to optimise the interaction of crotalarin, a blood group A-specific lectin from the seeds of Crotalaria striata with fetuin the effect of various parameters on the reaction has been studied turbidimetrically. The formation of crotalarin-fetuin complex was dependent on time, temperature, pH and the ionic strength of the medium. The maximum turbidity appeared in 30 min at 20 degrees C and the pH optimum was 3.5. The binding constant (Ka) for crotalarin-fetuin interaction was 5.58 x 10(4) M-1 (pH 3.5) at 20 degrees C. Among the different inorganic salts tested, the cations with increasing concentrations had pronounced effect on binding. KCNS and KI, however, were noninhibitory. The turbidity slightly increased in presence of different sodium salts, whereas periodate and urea reduced the interaction. The different alcohols had no remarkable effect on the above reaction.

Chemical modification studies on Cocos nucifera pollen allergens.

Hydrogen bonding pattern of nucleotides and carbohydrates has been analysed using Cambridge database. An analysis on ribonucleotides shows the 3' ···5' hydrogen bond mediated aggregation to be the most common alignment. The 2' ···5' alignment, which occurs under special circumstances in nature, is found to be the second choice. An analysis on carbohydrates suggests that self assembly of these molecules is not conducive to the formation of polysaccharides of the type which are found in present day living organisms. Further, the role of water molecules in the polymerization of three important biomolecules, namely nucleotides, carbohydrates and amino acids, has been analysed. Implication of these results to prebiotic polymerization is discussed.

Isolation of concanavalin A-reactive low-molecular weight allergen from house dust.

A concanavalin A-reactive low-molecular weight (MW approximately 7000) glycoprotein allergen has been isolated from house dust. The crude allergen was fractionated by Sephadex gel filtration followed by separation into two allergenic components by affinity chromatography on concanavalin A-Sepharose column. The column-bound fraction contains Man (11.7%), Gal (2.34%), GlcNAc (3.47%) and a trace of Glc and has been proved to be more potent allergen for house dust-sensitive patients both in vivo and in vitro tests.

Interaction and in vivo growth inhibition of Ehrlich ascites tumor cells by jacalin.

Jacalin has been found to agglutinate Ehrlich ascites cells. The agglutination was inhibited by a-glycosides of D-Gal and ß -D-Gal(1 → 3)-D-GalNAc suggesting that the lectin-ascites interaction was carbohydrate-specific. There was 21·8% inhibition of tumour (ascites) cell growth in vivo in mice administered 50μg of jacalin by injection for 6 days following intraperitoneal injection of ascites cells. Administration of 100, 150 and 200 μg jacalin resulted in 40·2, 57·5 and 83% inhibition respectively. The in vivo inhibition of tumour cells growth by jacalin was due to its preferential binding with D-Gal-a -( 1→6) present as terminal residues in the glycoprotein on tumour cell surface.