- Pune, India
Vetury Sitaramam
University of Pune, Biotechnology, Department Member
Assessment in schools is restricted to year-end or course-end tests that demand cramming which does not reflect true learning. The performance in these year-end examinations is skewed by socio-economic factors, besides the psychological... more
Assessment in schools is restricted to year-end or course-end tests that demand cramming which does not reflect true learning. The performance in these year-end examinations is skewed by socio-economic factors, besides the psychological stress induced and the resultant, unacceptable malpractices. Long term retention of school learning has not been recognized and developed into a viable alternative to assess what has been grasped by the student. We developed a quantitative design for a rapidly deployable test for long term retention as a viable alternative to assess true learning for the first time. While the data demonstrates drastic falling of retention with years of schooling towards more recent years, it has unique attributes depending on the subjects taught, independent of socioeconomic circumstances and gender, not apparent from the usual school tests. What has been learnt cannot be independent of what was taught and by whom and thus the test holds promise to assess the teacher...
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Whistler, the painter who saw it fit paint his elderly ‘mother’, was well known also for his wit. Once, appreciative of his particularly witty remark, (Lord) Byron remarked, “I wish I said that”. Whistler sardonically replied, “ You... more
Whistler, the painter who saw it fit paint his elderly ‘mother’, was well known also for his
wit. Once, appreciative of his particularly witty remark, (Lord) Byron remarked, “I wish
I said that”. Whistler sardonically replied, “ You will, you will”. So much was written
about plagiarism, honesty, values etc. in these columns that smacks of the “ol’ time
religion…”. Self-appointed societies rushing at the windmills of scientific compulsions
quixotically, committees after committees implicating and exonerating individuals in an
endless pursuit of the zero sum game, leaving the public at a totally confused state amidst a welter of accusations and counteraccusations….all this to what end? Is all this self hypnosis based on presumptive action? Actually, is plagiarism all that bad? Who or what is hurt? Let he who has not sinned be the first to throw a stone!
wit. Once, appreciative of his particularly witty remark, (Lord) Byron remarked, “I wish
I said that”. Whistler sardonically replied, “ You will, you will”. So much was written
about plagiarism, honesty, values etc. in these columns that smacks of the “ol’ time
religion…”. Self-appointed societies rushing at the windmills of scientific compulsions
quixotically, committees after committees implicating and exonerating individuals in an
endless pursuit of the zero sum game, leaving the public at a totally confused state amidst a welter of accusations and counteraccusations….all this to what end? Is all this self hypnosis based on presumptive action? Actually, is plagiarism all that bad? Who or what is hurt? Let he who has not sinned be the first to throw a stone!
J. Sci. Ind. Res. India. 47, 395 - 403, l988.
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The activity of hepatic tryptophan pyrrolase in rats exposed to cold increased rapidly and reached a maximum of three-fold at 8 h. On continued exposure up to 48 h stress, the activity partly decreased but remained at a level higher than... more
The activity of hepatic tryptophan pyrrolase in rats exposed to cold increased rapidly and reached a maximum of three-fold at 8 h. On continued exposure up to 48 h stress, the activity partly decreased but remained at a level higher than the initial. Withdrawal from the cold stress reversed the change. Adrenalectomy or treatment with inhibitors of protein synthesis abolished the increase in the enzyme activity during cold stress indicating a possible involvement of corticosteroids and de novo protein synthesis. Treatment with drugs known to block autonomic nervous system failed to inhibit the cold-mediated increase in enzyme activity. The results suggest that the increase in enzyme activity obtained on cold exposure is mediated by corticosteroids and not by either indoleaklylamines or autonomic nervous system. The changes in the enzyme obtained under cold stress with respect to the overshoot phenomenon, relationship to the degree of stress and reversibility on withdrawal from the st...
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Polymeric structures, namely, micelles, membranes and globular proteins share the property of two distinct regions: a hydrophobic core and a hydrophilic exterior. The dynamics of these regions of the polymeric structures were probed using... more
Polymeric structures, namely, micelles, membranes and globular proteins share the property of two distinct regions: a hydrophobic core and a hydrophilic exterior. The dynamics of these regions of the polymeric structures were probed using selective fluorophores 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-anilinonaphthalene-8-sulfonate (ANS), respectively. Perturbation of the polymers by external osmotic pressure, ionic strength and temperature was monitored in the two regions using steady state measurements of fluorescence intensity and anisotropy. While the fluorescence lifetime of DPH and ANS did not change significantly, parallel change in steady state anisotropy values and the rotational correlation time indicated mobility in the probe/probe-domain. Osmotic perturbation of the polymers in electrolyte media led to decreased DPH mobility. Enhanced ellipticity at 222 nm in bovine serum albumin was observed in 1.5 M NaCl and sucrose media. ANS exhibited a decreased anisotropy with progressive dehydration in proteins in NaCl media, in dimyristoylphosphatidylcholine (DMPC) vesicles in sucrose media, and in neutral laurylmaltoside micelles in both NaCl and sucrose media. Thus, ANS showed responses opposite to that of DPH in these systems. A comparison with several domain selective probes indicated that DPH reported findings common to depth probes while ANS reported data common to interfacial probes used for voltage monitoring.
Research Interests: Biochemistry, Biophysics, Chemistry, Physical Chemistry, Biophysical Chemistry, and 15 moreBiological Sciences, Fluorescence Lifetime, Micelles, Circular Dichroism, Physical sciences, Osmotic pressure, Proteins, CHEMICAL SCIENCES, Fluorescence anisotropy, Bovine Serum Albumin, Elsevier, Ionic Strength, Bsa, Cell Membrane, and fluorescent dyes
Research Interests: Chemical Engineering, Mathematics, Chemistry, Biology, Medicine, and 15 moreAntibiotic Resistance, Biological Sciences, Escherichia coli, Diffusion, Molecular Sieve, Membrane, Carbohydrate metabolism, Molecular Mass, Molecular weight, Non parametric statistics, Experimental Data, Nephelometry and Turbidimetry, Biochemistry and cell biology, Cell Membrane, and Cell membrane permeability
Bovine spermatozoa were shown to exhibit rapid regulatory volume decrease (RVD) when exposed to hypotonic saline media. This quinine- and quinidine-sensitive regulatory volume decrease was coincident with K1 release due to... more
Bovine spermatozoa were shown
to exhibit rapid regulatory volume decrease (RVD) when
exposed to hypotonic saline media. This quinine- and
quinidine-sensitive regulatory volume decrease was
coincident with K1 release due to stretch-activation of
inhibitor-specific presumptive K1 channels. The regulatory
volume decrease response was much faster than a
similar phenomenon observed in human peripheral
blood lymphocytes. Studies on volume changes in
different electrolyte and nonelectrolyte media suggested
that: (1) this inhibitor-specific channel could also
be a nonspecific pore in the spermatozoal membrane
for nonelectrolytes below 150 daltons; (2) subpopulations
(of nearly equal size) of the spermatozoa differ in
the expression of the pore; (3) capacitation abolishes
this distinction between subpopulations of spermatozoa;
and (4) the general case of RVD for other mammalian
spermatozoa was also established. Mol. Reprod.
Dev. 46:535–550, 1997. r 1997 Wiley-Liss, Inc.
to exhibit rapid regulatory volume decrease (RVD) when
exposed to hypotonic saline media. This quinine- and
quinidine-sensitive regulatory volume decrease was
coincident with K1 release due to stretch-activation of
inhibitor-specific presumptive K1 channels. The regulatory
volume decrease response was much faster than a
similar phenomenon observed in human peripheral
blood lymphocytes. Studies on volume changes in
different electrolyte and nonelectrolyte media suggested
that: (1) this inhibitor-specific channel could also
be a nonspecific pore in the spermatozoal membrane
for nonelectrolytes below 150 daltons; (2) subpopulations
(of nearly equal size) of the spermatozoa differ in
the expression of the pore; (3) capacitation abolishes
this distinction between subpopulations of spermatozoa;
and (4) the general case of RVD for other mammalian
spermatozoa was also established. Mol. Reprod.
Dev. 46:535–550, 1997. r 1997 Wiley-Liss, Inc.
Research Interests: Biochemistry, Biology, Medicine, Molecular, Motility, and 15 moreAnimals, Male, Respiration, Cattle, Capacitation, Potassium Channels, Spermatozoa, Quinine, Culture Media, Oxygen Consumption, Regulatory volume decrease, Biochemistry and cell biology, Buffaloes, Sperm capacitation, and Paediatrics and reproductive medicine
Crop improvement for Nitrogen Use Efficiency (NUE) requires a well-defined phenotype and genotype, especially for different N-forms. As N-supply enhances growth, we comprehensively evaluated 25 commonly measured phenotypic parameters for... more
Crop improvement for Nitrogen Use Efficiency (NUE) requires a well-defined phenotype and genotype, especially for different N-forms. As N-supply enhances growth, we comprehensively evaluated 25 commonly measured phenotypic parameters for N response using 4 N treatments in six indica rice genotypes. For this, 32 replicate potted plants were grown in the green-house on nutrient-depleted sand. They were fertilized to saturation with media containing either nitrate or urea as the sole N source at normal (15 mM N) or low level (1.5 mM N). The variation in N-response among genotypes differed by N form/dose and increased developmentally from vegetative to reproductive parameters. This indicates survival adaptation by reinforcing variation in every generation. Principal component analysis segregated vegetative parameters from reproduction and germination. Analysis of variance revealed that relative to low level, normal N facilitated germination, flowering and vegetative growth but limited y...
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Income/expenditures, individual expenditures such as education, and performance in schools all relate to systems with defined inputs and outputs and have been formally modeled in accordance with a systems theoretic approach. The Engel’s... more
Income/expenditures, individual expenditures such as education, and performance in schools all relate to systems with defined inputs and outputs and have been formally modeled in accordance with a systems theoretic approach. The Engel’s curves of expenditures on commodities from the Indian National Sample Survey Organization data was hyperbolic limited by a perceived ‘time constant’ associated with commodities while the preferences themselves are ordered hierarchically. School participation (dropouts) as a function of parental income based on available Brazilian data also shows a hierarchical hyperbolic relationship, thereby proving the nature of hierarchy in a naturally ordinal commodity - education. Since the socio-economic influences skew school performance in year-end examinations that demand cramming, retention over the years was tested in a school with a small cross section of 9th grade students uniformly distributed for their previous year’s school grades. The startling findi...
The study focuses quantitatively on ways to assess school education, currently under severe criticism, in terms the first of its three major components, students, teachers and curriculum,. We developed a novel method to assess long term... more
The study focuses quantitatively on ways to assess school education, currently under severe criticism, in terms the first of its three major components, students, teachers and curriculum,. We developed a novel method to assess long term retention as a measure of true learning in tests that do not involve any cramming and found to our dismay that it falls progressively more towards recent years. Our initial work on poverty showed that consumption on commodities is hyperbolic (as in catalysis) and hierarchic and, that the total income is not fractionally distributed among the commodities, as economists assume; the leftover (residual) income after the more essential items is spent on the commodities of lesser preference. Education is also a naturally ordered commodity and parental income quantitatively determined school dropouts/attendance obeying the same hyperbolic relationship, as we could show. We could thereby affirm the first-ever mechanism for Engels’ three curves of consumption...
Some degree of conceptualization would clearly occur during past traditional learning even if not formally realized as concept maps, since conceptual connectivity and progression are intuitively grasped. Can this be measured? The... more
Some degree of conceptualization would clearly occur during past traditional learning even if not formally realized as concept maps, since conceptual connectivity and progression are intuitively grasped. Can this be measured? The methodology for developing metrics for the ‘solidness’ of past learning has major prospects in the development of educational strategies, as retained learning alone can be true learning; it sheds light on ‘the disconnects’ that throw learning off-gear, when evaluated at a mass level. Here, we outline such a methodology that tantamounts to sleuthing for limits to true learning both in an individual and a group that the practitioners of concept maps may find useful, by reexamining for retention of past learning. Quantitation in retention together with concept maps complete the loop of learning, offering invaluable feedback where it is needed most, i.e., blind spots in learning.
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Dynamic states of biopolymers are associated with appearance and disappearance of spaces, or voids, to an extent larger than what is hitherto recognized. Current awareness of the existence of free space in biopolymers is by and large... more
Dynamic states of biopolymers are associated with appearance and disappearance of spaces, or voids, to an extent larger than what is hitherto recognized. Current awareness of the existence of free space in biopolymers is by and large restricted in terms of (i) essentially small pores obeying Boltzman distribution of sizes and energy and (ii) rigid structures dictated by structural constraints, whose volume merely exhibits fluctuations within the thermal limits. Interconnectivity of these spaces within biopolymers such as membranes give rises to new possibilities in addressing some of the long standing problems in understanding catalysis, transport and the derived biological phenomena. Given the a priori recognition that other kinds of space can exist in biopolymers, which are dynamic, predominantly inducible and possibly larger, a new kind of experimentation becomes possible as also a new set of constraints for the acceptability of molecular models of interactions in the explanation of biological phenomena. The theory of adsorption of liquids and presence of structural cavities as exemplified by zeolites competently accounts for much of the current thinking in our understanding of cavities in biopolymers. Induction of (larger) voids requires approaches that are significantly different. We suggest that it is necessary to consider a reservoir of inner space as a specific contribution to the energetics of polymer dynamics. We outline a methodological approach that helps identify these voids as well as biological phenomena in which the notion of dynamics of voids would bring novel insights. Copyright 1998 Academic Press
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Expression of the activity of the cytosolic enzyme lactate dehydrogenase released on cell lysis by tumour specific antibodies in the presence of complement was investigated by direct assay of the expression of the occluded enzyme in... more
Expression of the activity of the cytosolic enzyme lactate dehydrogenase released on cell lysis by tumour specific antibodies in the presence of complement was investigated by direct assay of the expression of the occluded enzyme in tumour cell suspensions. This method, called Enzyme Linked Immunolysis Assay (ELILA) was shown to be more sensitive than conventional cytotoxic assays. The data fit well in the linear regression model, so that the technique can be used for quantitation of the antibody titres.
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Bacterial respiration, endogenous as well as induced respiration by glucose, lactose and glycine betaine, was found to be sensitive to external solute concentration. Permeability of hydrogen peroxide, a non-electrolyte of molecular size... more
Bacterial respiration, endogenous as well as induced respiration by glucose, lactose and glycine betaine, was found to be sensitive to external solute concentration. Permeability of hydrogen peroxide, a non-electrolyte of molecular size between water and urea, through the bacterial membranes changed directly with the rate of respiration (an activity residing in the bacterial plasma membrane) in E. coli and the enhanced permeability and respiratory activity were highly correlated. Hydrogen peroxide permeability and induction of voids (spaces in the matrix of the bilayer into which hydrophobic fluorescent probes partition, which in turn were used to assess the modulation of these cavities) were shown to be a direct and excellent measure of leak conductance. Fluorescence intensity and anisotropy of the extrinsic fluorescent probes (incorporated by growing bacteria in their presence) decreased with increased respiration in bacteria, consistent with lowered molecular restriction and enhanced hydration in the membrane phase for these probes as seen in dimyristoylphosphatidylcholine bilayers due to phase transition. The physical basis of osmotic phenomena, as a relevant (thermodynamic) volume, could relate to water exchange or compression, depending on the osmotic domain. In the domain of compression in bacteria, i.e. well above the isotonic range, the computed activation volume was consistent with voids in the membrane. This study emphasises a major role of leak conductance in bacterial physiology and growth.
Research Interests: Algorithms, Kinetics, Biophysical Chemistry, Anisotropy, Biological Sciences, and 15 moreEscherichia coli, Biopolymers, Physical sciences, Osmotic pressure, Phase transition, CHEMICAL SCIENCES, Hydrogen Peroxide, Fluorescent probes, Fluorescence anisotropy, Glycine, Glycine Betaine, Nephelometry and Turbidimetry, Oxidants, Betaine, and Cell Membrane
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Osmotic titration of ATPase activity in rat liver mitochondria was consistent with enhanced porosity of the mitochondrial inner membrane to mannitol due to ATP hydrolysis even when endogenous respiration was inhibited by rotenone. The... more
Osmotic titration of ATPase activity in rat liver mitochondria was consistent with enhanced porosity of the mitochondrial inner membrane to mannitol due to ATP hydrolysis even when endogenous respiration was inhibited by rotenone. The occluded ATPase activity, which exhibits osmotic activation with an optimum near isotonicity, depends both on the ATPase activity per se and on the activity of the ADP/ATP carrier. Purified ADP/ATP carrier incorporated into small, unilamellar liposomes was critically shown to exhibit dependence of its activity on the osmotic pressure differences across the membrane, with maximal activity corresponding to isotonicity, regardless of the actual internal tonicity.
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The osmotic basis of low and high amplitude swelling in mitochondria was investigated in detail using sucrose and mannitol as external osmolytes. Osmotic behaviour of mitochondria in various respiratory states was consistent with... more
The osmotic basis of low and high amplitude swelling in mitochondria was investigated in detail using sucrose and mannitol as external osmolytes. Osmotic behaviour of mitochondria in various respiratory states was consistent with significant changes in the porosity of the inner membrane corresponding to the rate of respiration. The stoichiometry of oxidative phosphorylation was confirmed to be dependent on the physical state (i.e., osmotic stretch) of the inner membrane regardless of the external polyol used. High amplitude swelling in polyol media was shown to arise from a sequential disruption of the outer and inner mitochondrial membranes, due to a dynamic instability induced by a combination of respiration, unscreened (fixed) surface charge density and the consequent variable porosity of the inner membrane. These novel experimental findings based on the physical theory of osmosis emphasize the need to define the fine structural changes of the inner membrane associated with oxidative phosphorylation to arrive at a comprehensive mechanism.
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Membrane proteins exhibit charge anisotropy across the bilayer with the vector positive inwards. The proton pumps, primary or secondary, which have been examined as a subset of these membrane proteins, also reveal charge anisotropy based... more
Membrane proteins exhibit charge anisotropy across the bilayer with the vector positive inwards. The proton pumps, primary or secondary, which have been examined as a subset of these membrane proteins, also reveal charge anisotropy based on their sequence data. The direction of the anisotropy appears to satisfy the observed directional gradient of protons mediated by these proteins. A correct description of transport requires attention to local as well as field effects of the charge anisotropy of membrane proteins.
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Metabolically-induced (spontaneous) high amplitude swelling of mitochondria has been shown to be due to a serial disruption of the mitochondrial membranes [D. Sambasivarao & V. Sitaramam (1985), Biochim Biophys Acta, 806,... more
Metabolically-induced (spontaneous) high amplitude swelling of mitochondria has been shown to be due to a serial disruption of the mitochondrial membranes [D. Sambasivarao & V. Sitaramam (1985), Biochim Biophys Acta, 806, 195-209]. Phosphate- and arsenate-induced swelling was investigated in mitochondria to evaluate the role of phosphate transport in the instability created in the mitochondrial membranes. Phosphate-induced swelling in respiring mitochondria was similar to spontaneous swelling. Both represent essentially colloidal swelling due to the variable porosity induced in the inner membrane to polyols by respiration. Swelling of non-respiring mitochondria at high ammonium phosphate concentrations was, on the other hand, primarily due to high permeability to phosphate. This membrane instability created by phosphate transport in the surrounding lipid involves neither the endogenous nor the exogenous Ca2+.
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While many plants and trees in specific areas acquire cult significance, very few such as Ficus religiosa L. have acquired a universal status. This hemiepiphyte, Ficus religiosa L., is of dual interest since it venerated by a quarter of... more
While many plants and trees in specific areas acquire cult significance, very few such as Ficus religiosa L. have acquired a universal status. This hemiepiphyte, Ficus religiosa L., is of dual interest since it venerated by a quarter of the present mankind (Hindus and Buddhists, largely Asian) on one hand and also since these plants are blamed for destruction of buildings due to their ability to grow on buildings. Divergence in views exists whether epiphytic plants exert a destructive influence on buildings. A focused survey of the coastal forts on land and sea has shown uniformly that the naturally growing plants of certain Ficus sp., notably Ficus religiosa L., grow exclusively on the vertical sheer side of rock faces and not either on the ground or on the top surface of these 8-10 centuries old rock structures; also seen on the side of rock piles as recent as 4-5 years as well as in sacred groves of several centuries to millennia old. We could trace the roots through these struct...
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Availability of voids for diffusion of quinone in the membrane was shown to be the rate-limiting step in electron transport in mitochondria and chloroplasts (Mathai, J. C., Sauna, Z. E., John, O., and Sitaramam, V (1993) J. Biol. Chem.... more
Availability of voids for diffusion of quinone in the membrane was shown to be the rate-limiting step in electron transport in mitochondria and chloroplasts (Mathai, J. C., Sauna, Z. E., John, O., and Sitaramam, V (1993) J. Biol. Chem. 268, 15442-15454). The primary role of voids in these diffusion-controlled reactions required a more rigorous documentation of the role of diffusion in membranes by independent measurements. The transbilayer diffusion of hydrogen peroxide as monitored by occluded catalase activity was developed as a kinetically valid probe to specifically address this question. This in turn led to unique results on the mechanistic basis of stretch (= hypo-osmotic) activation of hydrogen peroxide permeation via such voids. The rate of peroxide permeation is shown to be markedly stretch sensitive in some cells/organelles (e.g. peroxisomes) and insensitive in others (e.g. erythrocytes); this was equally true of liposomes prepared from lipids extracted from the correspond...
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The high osmotic potential inhibition of photosynthetic electron transport was determined to be related to membrane compaction rather than to an effect of primary thylakoid volume changes. Osmotic inhibition of proton fluxes and... more
The high osmotic potential inhibition of photosynthetic electron transport was determined to be related to membrane compaction rather than to an effect of primary thylakoid volume changes. Osmotic inhibition of proton fluxes and phosphorylation were entirely due to osmotic inhibition of electron transport. The ATPase activity, the nature of coupling and the rate constant of proton efflux were not influenced by osmotic pressure, while the rate constant and the extent of proton influx were inhibited by osmotic pressure.