Richards, M. P. and R. J. Cousins. 1976b. Zinc-binding protein: relationship to short term changes in zinc metabolism. Proc. Soc. Expl. Biol. Med. 153:52–56.

In an ideal lens, light from any given point of an object would pass through the lens and come together at a single point in the image plane. Contrary to ideal lenses, real lenses do not focus light to a single point. These deviations from the idealized lens performance are known as an aberration of the lens.

Spherical aberrationin mirrors

When the light is not monochromatic (not of a single wavelength), a sixth aberration is found in lenses but not in mirrors and is named chromatic aberration.

Spherical aberrationexample

Animal Parasitology Institute Protozoan Diseases Laboratory, USDA Agricultural Research Service, Beltsville, MD, 20705, USA

Astigmatism is the result of the failure of a single zone of the lens to focus the image of an off-axis point at a single point. In the figure, we see two planes perpendicular to each other passing through the optical axis. These planes are known as the meridian plane and the sagittal plane, the meridian plane being the one containing the off-axis object point. Skew rays, rays not in the meridian plane are focused farther away from the lens than those lying in the plane. In either case, the rays do not meet in a point focus but as lines perpendicular to each other. Intermediate between these two positions, the images are elliptical in shape.

Spherical aberrationcorrection

Cousins, R. J. and A. R. Burges. 1984. Influence of glucagon and epinephrine on metallothionein induction and zinc exchange in rat liver parenchymal cells. Fed. Proc. 44:3403.

The ubiquitous distribution of zinc (Zn) in microbial, plant and animal cells suggests a wide range of potential functions for this transition element. The physiological role of Zn has centered on its interaction with enzymes. For example, the cessation of growth associated with nutritional Zn deficiency involves a reduction in DNA polymerase activity and concomitant reduction in DNA synthesis. Similarly, RNA polymerases I, II, and III are all Zn metalloenzymes and in appropriate model systems a reduction in the synthesis r-RNA, mRNA and t-RNA, respectively, is observed with cellular Zn depletion. The effect of Zn at the genetic level is most dramatically shown through induction of metallothionein synthesis. This protein influences the kinetics of Zn uptake by cells. It has been clearly demonstrated that metallothionein synthesis is under transcriptional control. Zinc and glucocorticoids, as well as glucagon and epinephrine (via elevation of cellular cAMP levels) all induce transcription of the metallothionein gene. Recently it has been shown that a 12 by fragment of the metallothionein gene promoter sequence regulates expression of heterologous genes in vivo, which demonstrates that Zn can have a direct effect on expression of specific genes. These results illustrate the potential of this relatively nontoxic metal in biotechnology applications where Zn responsive fusion genes could be utilized.

Richards, M. P. and R. J. Cousins. 1976a. Metallothionein and its relationship to the metabolism of dietary zinc in rats. J. Nutr. 106:1591–1599.

Falchuk, K. H., B. Mazus, L. Ulpino and B. L. Vallee. 1976. Euglena gracilis DNA dependent RNA polymerase II: a zinc metalloenzyme. Biochemistry 15:4468–4475.

Hamer, D. H. and M. Walling. 1982. Regulation in vivo of a cloned mammalian gene: cadmium induces the transcription of a mouse metallothionein gene in SV 40 vectors. J. Mol. Appl. Genet. 1:273–288.

Spherical aberrationimage

Failla, M. L. and R. J. Cousins. 1978. Zinc uptake by isolated rat liver parenchymal cells. Biochem. Biophys. Acta 538:434–444.

Wandzilak, T. M. and R. W. Benson. 1977. Yeast RNA polymerase III: a zinc metalloenzyme. Biochem. Biophys. Res. Comm. 76:247–252.

Wacker, W. E. C. 1962. Nucleic acids and metals, III. Changes in nucleic acid, protein and metal content as a consequence of zinc deficiency in Euglena gracilis. Biochemistry 1:859–865.

Palmiter, R. D., H. Y. Chen and R. D. L. Brinster. 1982a. Differential regulation of metallothionein-thymidine kinase fusion genes in transgenic mice and their offspring. Cell 29:701–710.

Ferrin, L. J., A. S. Mildvan and L. A. Leob. 1983. Metal content of DNA polymerase I purified from overproducing and wild type Escherichia coli. Biochem. Biophys. Res. Comm. 112:723–727.

Palmiter, R. D., R. L. Brinster, R. E. Hamer, M. E. Trumkbauer, M. G. Rosenfeld, N. C. Birnberg and R. M. Evans. 1982b. Dramatic growth of mice that develop from eggs microinjected with metallothionein-growth hormone fusion genes. Nature 300:611–615.

Squibb, K. S. and R. J. Cousins. 1974. Control of cadmium binding protein synthesis in rat liver. Environ. Physiol. Biochem. 4:24–30.

Williams, R. O. and L. A. Loeb. 1973. Zinc requirement for DNA replication in stimulated human lymphocytes. J. Cell Biol. 58:594–601.

Wegener, W. S. and A. H. Romano. 1963. Zinc stimulation of RNA and protein synthesis in Rhizopus nigrican. Science 142:1669–1670.

Spherical aberrationand chromaticaberration

Falchuk, K. H., A. Krishan and B. L. Vallee. 1975. DNA distribution in the cell cycle of Euglena gracilis, cytofluorometry of zinc deficient cells. Biochemistry 14:3439–3444.

Prasad, A. S. and D. Oberleas. 1974. Thymidine kinase activity and incorporation of thymidine into DNA in zinc-deficient tissue. J. Lab. Chin. Med. 83:634.

Cousins, R. J. 1985. Absorption, transport, and intracellular metabolism of copper and zinc: special reference to metallothionein and ceruloplasmin. Physiol. Rev. 65:238–309.

Terhune, M. W. and H. H. Sandstead. 1972. Decreased RNA polymerase activity in mammalian zinc deficiency. Science 177:68–69.

The image depicts a case of spherical aberration. The most spherical aberration-free image is found at the circle of least confusion.

When the light of a single wavelength is considered, there are five monochromatic aberrations to be considered and they are:

Fosmire, G. J., Y. Y. Al-Ubaidi, E. Halas and H. H. Sandstead. 1974. The effect of zinc deprivation on the brain. Adv. Expl. Med. Biol. 48:329–345.

Chesters, J. K. 1972. The role of zinc ions in the transformation of lymphocytes by phytohaemagglutinin. Biochem. J. 130:133–319.

Spherical aberrationphotography

Swenerton, H., R. Shrader and L. S. Hurley. 1969. Zinc-deficient embryos: reduced thymidine incorporation. Science 166:1014–1015.

Sandstead, H. H. and R. A. Rinaldi. 1969. Impairment of deoxyribonucleic acid synthesis by dietary zinc deficiency in the rat. J. Cell Physiol. 73:81–84.

Etzel, K. R., M. R. Swerdel, J. N. Swerdel and R. J. Cousins. 1982. Endotoxin-induced changes in copper and zinc metabolism in the syrian hamster. J. Nutr. 112:2363–2373.

Butt, T. R., E. J. Sternberg, J. A. Gorman, P. Clark, D. Hamer, M. Rosenberg and S. T. Crooke. 1984. Copper metallothionein of yeast, structure of the gene, and regulation of expression. Proc. Nat. Acad. Sci. 81:3332–3336.

Petranyi, P., J. J. Jendrisak and R. R. Burgess. 1977. RNA polymerase II from wheat germ contains tightly bound zinc. Biochem. Biophys. Res. Comm. 74:1031–1038.

Thornalley, P. J. and M. Vasak. 1985. Possible role for metallothionein in protection against radiation-induced oxidative stress. Kinetics and mechanisms of its reaction with superoxide and hydroxyl radical. Biochim. Biophys. Acta 827:36–44.

Lieberman, I., R. Abrams, N. Hun and P. Ove. 1963. Levels of enzyme activity and deoxyribonucleic acid synthesis in mammalian cells cultured from the animal. J. Biol. Chem. 238:3935–3962.

DiSilvestro, R. A. and R. J. Cousins. 1984. Glucocorticoid independent mediation of interleukin-1 induced changes in serum zinc and liver metallothionein levels. Life Sci. 35:2113–2118.

Carter, A. D., B. K. Felder, M. T. Walling, M. F. Jubier, C. J. Schmidt and D. H. Hamer. 1984. Duplicated heavy metal control sequences of the mouse metallothionein-I gene. Proc. Nat. Acad. Sci. 81:7392–7396.

Springgate, C. F., A. S. Mildvan, R. Abramson, J. L. Engle and L. A. Leob. 1973. Escherichia coli deoxyribonucleic acid polymerase I, a zinc metalloenzyme. J. Biol. Chem. 248:5987–5993.

The failure of a lens to focus all colours in the same plane is known as chromatic aberration. The refractive index for red is least at the red end of the spectrum, hence the focal length of a lens in the air will be greater for red and green than it would be for blue and violet. Chromatic aberration affects magnification along the optical axis and the axis perpendicular to it. The former is known as longitudinal chromatic aberration and the latter is known as lateral chromatic aberration.

Bryan, S. E., D. L. Vizard, D. A. Beary, R. A. LaBiche and K. J. Hardy. 1981. Partitioning of zinc and copper within subnuclear nucleoprotein particles. Nucl. Acids Res. 9:5811–5821.

Cousins, R.J. (1986). Molecular biology of zinc. In: Augustine, P.C., Danforth, H.D., Bakst, M.R. (eds) Biotechnology for Solving Agricultural Problems. Beltsville Symposia in Agricultural Research, vol 10. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-4396-4_16

DiSilvestro, R. A. and R. J. Cousins. 1984. Mediation of endotoxin-induced changes in zinc metabolism in rats. Amer. J. Physiol; 247:E436–E441.

Scrutton, M. C., C. W. Wu and D. A. Goldthwait. 1971. The presence and possible role of zinc in RNA polymerase obtained from Escherichia coli. Proc. Nat. Acad. Sci. 68:2497–2501.

Stuart, G. W., P. F. Searle, H. Y. Chen, R. L. Brinster and R. D. Palmiter. 1984. A 12-base-pair DNA motif that is repeated several times in metallothionein gene promoters confers metal regulation to a heterologous gene. Proc. Nat. Acad. Sci. 81:7318–7322.

Prasad, A. S., P. Rabbani, A. Abbasil, E. Bowersox and M. R. S. Fox. 1978. Experimental zinc deficiency in humans. Ann. Intern. Med. 89:483–490.

Smeyers-Verbeke, J., C. May, P. Drochmans and D. L. Massart. 1977. The determination of Cu, Zn, and Mn in subcellular rat liver fractions. Anal. Biochem. 83:746–753.

Anderson, R. D., B. W. Birren, T. Gans, J. E. Piletz and H. R. Herschman. 1983. Molecular cloning of the rat methallothionein-I (MT-1) mRNA sequence. DNA 2:15–22.

Mazus, B., K. H. Falchuk and B. L. Vallee. 1984. Histone formation, gene expression, and zinc deficiency in Euglena gracilis. Biochemistry 23:43–47.

In spherical aberration, rays of light from a point on the optical axis of a spherical lens do not all meet at the same image point. Rays passing closer to the center are focussed farther away than the rays passing through a circular zone near its rim. A circular cross-section is formed whenever a plane held perpendicular to the optical axis is made to intersect a cone. The area of the cross-section varies with the distance along the optical axis. The smallest size is known as the circle of least confusion. The most spherical aberration-free image is found at this distance.

Wynshaw-Boris, A., T. G. Lugo, J. M. Short, R. E. K. Fournier and R. W. Hanson. 1984. Identification of a cAMP regulatory region in the gene for rat cytosolic phosphoenolypyruvate carboxykinase (GTP). J. Biol. Chem. 259:12161–21269.

Richards, M. P. and R. J. Cousins. 1975. Mammalian zinc homeostasis: requirements for RNA and metallothionein synthesis. Biochem. Biophys. Res. Comm. 64:1215–1223.

Quinones, S. R. and R. J. Cousins. 1984. Augmentation of dexamethasone induction of rat liver metallothionein by zinc. Biochem. J. 219:959–963.

Brady, F. O. and B. Helvig. 1984. Effect of epinephrine and norepinephrine on zinc thionein levels and induction in rat liver. Amer. J. Physiol. 247:E318–E322.

Department of Food Science and Human Nutrition, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, 32611, USA

Alfaro, B. and F. Heaton. 1974. The subcellular distribution of copper, zinc, and iron in liver and kidney. Changes during copper dificiency in the rat. Br. J. Nutr. 32:435–445.

Auld, D. S., H. Kawaguhi, D. M. Livingson and B. L. Vallee. 1974. RNA-dependent DNA polymerase (reverse transcriptase) from avian myeloblastosis virus: a zinc metalloenzyme. Proc. Nat. Acad. Sci. 71:2091–2095.

Prasad, A. S., D. Oberleas, D. Koniuch and E. DuMouchelle. 1973. Ribonuclease and deoxyribonuclease activities in zinc-deficient tissues. J. Lab. Clin. Med. 82:461–466.

Spherical aberrationcause

Etzel, K. R., S. G. Shapiro and R. J. Cousins. 1979. Regulation of liver metallothionein and plasma zinc by the glucocorticoid dexamethasone. Biochem. Biophys. Res. Comm. 89:1120–1126.

Rubin, H. 1972. Inhibition of DNA synthesis in animal cells by ethylene diamine tetraacetate, and its reversal of zinc. Proc. Nat. Acad. Sci. 69:712–716.

The name “Coma” is derived from the fact that a point image is blurred into a comet shape when rays from an off-axis object point are imaged by different zones of the lens. In spherical aberration, the images of an object point that fall on a plane perpendicular to the optical axis are circular in the shape of varying sizes and superimposed about a common centre. In a coma, the images of an off-axis object point are circular, of varying size, but displaced with respect to each other.

Macapinlac, M. P., W. N. Pearson, G. H. Barney and W. J. Darby. 1968. Protein and nucleic acid metabolism in the testes of zinc-deficient rats. Nutrition 95:569–577.

Slaby, I., B. Kind and A. Holmgren. 1984. T7 DNA polymerase is not a zinc-metalloenzyme and the polymerase and exonuclease activities are inhibited by zinc ions. Biochem. Biophys. Res. Commun. 122:1410–1417.

Shapiro, S. G. and R. J. Cousins. 1980. Induction of rat liver metallothionein mRNA and its distribution between free and membrane-bound polysomes. Biochem. J. 190:755–764.

Shapiro, S. G., K. S. Aquibb, LK. A. Markowitz and R. J. Cousins. 1978. Cell-free synthesis of metallothionein directed by rat liver polyadenylated messenger RNA. Biochem. J. 175:833–840.

Sandstead, H. H., M. Terhune, R. N. Brady, D. Gillespie and W. L. Holloway. 1971. Zinc deficiency: brain DNA protein and lipids; and liver ribosomes and RNA polymerase. Clin. Res. 19:83–89.

Spherical aberrationin a lens

Kreutzfeld, K. L., K. Y. Lei, M. D. Bergman and F. L. Meyskens, Jr. 1985. Dexamethasone and zinc in combination inhibit the anchorage-independent growth of S-91 cloudman murine melanoma. Life Sci. 36:823–827.

The image shows two images, one resulting from a central cone of rays and the other from a cone passing through the rim.

Udom, A. O. and F. O. Brady. 1980. Reactivation in vitro of zinc-requiring apo-enzymes by rat liver zinc-thionein. Biochem. J. 187:326–335.

Somers, M. and E. J. Underwood. 1969. Ribonuclease activity and nucleic acid and protein metabolism in the testes of zinc-deficient rats. Austral. J. Biol. Sci. 22:1277–1282.

Schneider, E. and C. A. Price. 1962. Decreased ribonucleic acid levels: a possible cause of growth inhibition in zinc deficiency. Biochem. Biophys. Acta 55:406–410.

Li, T. Y., A. J. Kramer, C. F. Shaw III and D. H. Petering. 1980. Ligand substitution reactions of metallothionein with EDTA and apo-carbonic anhydrase. Proc. Nat. Acad. Sci. USA 77:6334–6338.

In optics, aberration is a property of optical systems such as lenses that results in light being spread out over some region of space rather than being focused to a point. An image-forming optical system with aberration will produce an image that is not sharp. Aberration can be caused due to a variety of reasons such as lens size, material, thickness and position of the object. In this article, let us learn more about aberration and its type.

Karin, M. and R. I. Richards. 1982. Human metallothionein genes — primary structure of the metallothionein-II gene and a related processed gene. Nature (London) 299:797–802.

O’Neal, R. M., G. W. Pla, M. R. S. Fox, F. S. Gibson and B. E. Fry, Jr. 1970. Effect of zinc deficiency and restricted feeding on protein and ribonucleic acid metabolism of rat brain. J. Nutr. 100:491–497.

Coppen, D. E., R. J. Cousins and D. E. Richardson. 1985. Effect of zinc on chemically induced peroxidation in rat liver parenchymal cells in primary culture. Fed. Proc. 44:6404.

Durnam, D. M., F. Perrin, F. Gannon and R. D. Palmiter. 1980. Isolation and characterization of the mouse metallothionein-I gene. Proc. Nat. Acad. Sci. USA 77:6511–6515.

Squibb, K. S., R. J. Cousins and S. L. Feldman. 1977. Control of zinc-thionein synthesis in rat liver. Biochem. J. 164:223–228.

Falchuk, K. H., L. Ulpino, B. Maxus and B. L. Vallee. 1977. E. Gracilis RNA polymerase I: a zinc metalloenzyme. Biochem. Biophys. Res. Comm. 74:1206–1212.

The curvature of field and distortion refer to the location of image points with respect to one another. The former three aberrations mentioned so far can be corrected by making corrections in the design of the lens, but these two aberrations could remain. In curvature of the field, the image of a plane object perpendicular to the optical axis will lie on a paraboloidal surface known as the Petzval Surface. Distortion, on the other hand, refers to the deformation of an image. There are two kinds of deformation, namely barrel distortion and pincushion distortion.