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Distribution of several glycolytic enzymes in the lenses of different vertebrate species and theirorganization in the calf lenses were studied. Though no general pattern of enzyme activities in different species is discernible, high activities of TPI followed, in decreasing order, by GAPDH, enolase, PK, LDH and aldolase appear to be more common. Our observation on the unusually high activities of aldolase in the pig, enolase in the sheep and LDH in the duck lens are interesting in view of the already known dual function of LDH as an enzyme and a structural protein ( e -crystallin) in duck. Controlled treatment with detergents Brij-58 and Triton X-100 caused distinctly differential purturbations in the lens cells. In spite of fiber membrane disruption and partial actin dissolution by Brij-58, no significant increase in the release of glycolytic enzymes compared to control was observed. This suggests that none of the enzymes existed as a completely soluble and freely diffusible fraction. But treatment with a strong detergent (Triton X-100) caused the release of higher amounts of enzymes suggesting either a direct or indirect interaction with the cytomatrix components. Aldolase appears to be maximally bound in the cytosol followed by TPI, GAPDH, LDH and PK in decreasing order. Although thin lens slices were incubated with the detergents for a total period of 40 min and the loss of fiber architecture and organization confirmed by light microscopy, in the Triton- X-100 treated tissues less than 25% of the total activity of any enzyme except TPI appeared in the bathing medium. Such a restricted diffusion of enzymes from the tissues suggests significant protein-protein interactions. The present study indicates highly variable activities of glycolytic enzymes in different species and an ordered array of these enzymes in the cytomatrix.

The highly selective nature of protein-ligand interactions provides a sensitive mechanism for the modulation of cellular activity by proteins. In the eye lens the supramolecular order of the lens crystallins, which is expected to be susceptible to protein electrostatic charge, in part defines transparency. The binding of charged ligands to proteins is one way of achieving an alteration in protein electrostatic charge. Evidence is presented that L-alpha-glycerophosphate, a major phosphorus metabolite of eye lens metabolism, binds to the globular protein, gamma-crystallin with moderately high affinity and in a positive cooperative manner. The following binding parameters were obtained from equilibrium measurements: minimum number of binding sites, n = 2; Kassoc = 6.2 +/- 0.5 x 10(3) M-1; cooperativity parameter, alpha H = 1.9 +/- 0.1. Interactive computer graphics display techniques were used to locate putative ligand binding sites, and in turn, to identify the possible molecular interactions responsible for the binding of ligand to protein at one of the sites. One putative binding site was located in the cleft between the two domains of gamma II-crystallin. Arginyl residues 79 and 147 are involved in ligand binding as are the peptide carbonyl oxygens of residues Tyrosyl-50 and Aspartyl-156. Five hydrogen bonds between the ligand and the protein structure are predicted for the binding of L-alpha-glycerophosphate, whereas only 3 occur for the binding of the "unnatural" D-enantiomorph. Modulation of both lens protein supramolecular organization and lens metabolism is predicted to be a consequence of L-alpha-glycerophosphate binding to gamma-crystallin in the lens.

The existence of variability in the cereal cyst nematode, Heterodera avenae Woll. in India is confirmed. Tentatively five biotypes have been identified using an assortment of cereals and grasses; the distribution of the biotypes in the light soils of Rajasthan and Haryana is plotted. These biotypes do not appear to be identical to those in Denmark, The Netherlands, Britain, Germany and Australia. They have been designated as 1, 2, 3, 4 and 5 of which biotype 3 is the most common in India. The possibilities of the existence of more biotypes is also indicated.

Taurine, a putative neurotransmitter, cysteinyl sulphinlic acid α-ketogluraric acid transaminase (CSA-T) and cysteinyl sulphinlic acid decarboxylase (CSA-D) were measured in the different structures of the rat olfactory bulb and olfactory nucleus. It appears there are significant differences between the level of taurine in internal layers (mitral cells, plexiform) and external layer such as fibrorum. The CSA-T and CSA-D activities followed approximately the distribution of taurine in the different areas of the rat olfactory bulb and nucleus. A very high activity of CSA-T was present in all areas studied and a role for the enzyme is proposed. The cellular distribution of CSA-T, CSA-D and taurine is compared with the distribution in retina.

Cysteine sulfinate (CSA) carboxylyase, the enzyme which synthesizes taurine through hypotaurine, shows a higher activity in the inner plexiform and nuclear layer of adult chick retina compared to the outer plexiform and nuclear layers whereas the outer segments of photoreceptors do not show any activity of this enzyme. These observations suggest an endogenous synthesis of taurine preferentially in certain layers of retina. Therefore, taurine fulfills one more criteria which is required by a substance to be accepted as a neurotransmitter in an organ. Studies on the distribution of CSA-carboxylyase in the visual pathway and other brain areas show a very high activity of this enzyme in optic tectum followed by cerebral cortex, cerebellum, retina, lateral geniculate body and optic nerve, taken with chiasma and tract in decreasing order. On the other hand, analysis of the free amino acid pool reveals a very high content of taurine in retina as compared to optic tectum. Cysteine sulfinate carboxylyase activity and the content of taurine therefore do not seem to bear a good correlation and other mechanisms of release, uptake and degradation might be involved in regulating the taurine content in these tissues.

Marked heterogeneity was observed in the distribution of taurine in different regions of the lens in various species. In general low taurine pools were observed in the nucleus of all species except frog and human. The distribution of taurine in human senile cataractous lenses at different stages of maturation showed decreased contents in all the regions except capsule epithelium as compared to the normal human lenses. This decrease is progressive upto the ‘mature’ stage of cataract. In rat lenses with galactose cataracts taurine contents decreased by about 83–94% of the normal values in the equatorial, anterior, posterior cortical and nuclear regions.

The occurrence of large taurine pool sizes in the crystalline lens was further elucidated by studying the in vitro synthesis and uptake of taurine in the rat lens. It was observed that a time- and concentration-dependent synthesis of taurine from methionine occurred in the rat lens. The time curve for uptake was linear up to 4 hr and was not saturated up to 40 m m concentration of taurine. The uptake was inhibited by ouabain, cyanide, Ca 2+ , GTP and cGMP but was not affected by ATP and cAMP. It is suggested that a dual mechanism exists for maintenance of high concentrations of taurine in the lens. Moreover, the uptake mechanism is energy-dependent.