Electrophoretic separation of proteins

There are several structural and storage proteins in the tissues of Crustacea. Some of them are metallo-proteins, some are enzymic in nature. Several electrophoretic procedures were used for the separation of these proteins. The methods used by crustacean workers include paper (Zuckerkandl, 1956; Hughes & Winkler, 1966 ; Stewart, et al., 1969), agar gel (Decleir, 1961; Vranckx &Durlait, 1976), starch gel (Whittaker, 1959 ; Cowden & Coleman, 1962; Dall, 1964) and polyacrylamide gel electrophoresis (Dall, 1974; Durliat et al., 1975; Alikhan & Akthar, 1980). With polyacrylamide gel electrophoresis a good resolution is achieved with minimum quantity of blood sample (0.1 ml). Here polyacrylamide gel electrophoretic method of Davis (1964) is described

Copper

Copper is an essential element found in the blood and other tissues of Crustacea. It forms a part of cuproprotein required for oxygen transport and electron transport systems. It also forms as prosthetic group in many enzymes such as phenol oxidase and acts as activator for enzymes such as malate dehydrogenase. It is toxic in free state (Holden, 1970) and dialysable copper is absent in the blood of crustaceans (Arumugam & Ravindranath, 1980). The copper exists in blood both in the cuprous and cupric state and is linked with protein through sulphydryl groups (Klotz & Klotz, 1955). Several methods are in vogue for determination of copper. Some of them are suitable for vertebrate tissue where it is 100 times lower than the crustacean blood or other tissues. Here the suitability and consistency of 3 spectrophotometry methods were analysed for determination of crustacean blood or other tissue copper concentration

Proteins

The nitrogen of the protein precipitate is converted to acid ammonium sulphate by digestion with sulphuric acid and various catalysts. On making the reaction mixture alkaline, ammonia is liberated, which is removed by steam distillation. The ammonia liberated by steam distillation is gathered in acid solution containing an indicator. Change in pH of the acid solution due to addition of ammonia is indicated by the indicator dye. This solution is back-titrated with 0.01 N HCI, and the original acidic condition indicated by the indicator dye, is taken as the end point. The amount of HCl consumed in back titration is proportional to the amount of ammonia liberated. Percentage of nitrogen is calculated from the titre value, which is converted into gm% of protein present in sample by multiplying the percentage nitrogen with a factor 6.2S. The factor 6.25 is used for conversion because in average, protein contains 16% of nitrogen

Effects of the surgical excision of the sinus gland and eyestalk ablation on osmotic regulation

Sinus gland is a neurohaemal organ wherein hormones from different neurosecretory centres are stored. The sinus gland of Scylla serrata is well developed and macroscopically visible owing to its well known characteristic opacity and slightly bluishhue. It is located at the dorsal aspect of the junction between the medulla interna and the medulla terminalis in the eyestalk. Since it is a compact structure it is possible to remove the sinus gland from the eyestalk. There are two surgical procedures for the removal of the sinus gland. The first procedure involves the removal of the retinal portion of the eye cap and the other involves surgical excision without disturbing the eye cap and thereby the vision of the crab (Kleinholz, 1947)

Total free sugars, reducing sugars and glucose

Carbohydrates in the tissues of crustaceans exist as free sugars and as bound with proteins (Saravanan, 1979). The free sugars in haemolymph consist of mono, di and oligosaccharides. All monosaccharides, maltose and its oligosaccharides constitute the total reducing sugars. Trehalose constitutes the non-reducing sugar fraction of the total free sugars. The total free sugars are estimated by Anthrone method and reducing sugar by Nelson-Somogyi method. The difference in the values obtained by these two methods indicates total non-reducing sugar value which is primarily trehalose in crustacean blood. The glucose can be determined by Glucose-oxidase method. The difference between values of glucose and reducing sugars would indicate the concentration of non-glucose reducing sugars

Calcium

Calcium in tissues of crustaceans exists in two states namely diffusible and non-diffusible. Diffusible calcium is also referred to as dialysable and ultra filterable calcium, which includes free calcium ions and calcium complexed with carbonate, citrate, phosphate and free acidic amino acids. Non-diffusible calcium is referred to as non-dialysable calcium and non-ultra filterable calcium. It is also commonly called as bound-calcium. In this state, calcium may be bound to proteins, lipids and acidic mucosubstances. Bound calcium is precipitable with 80% ethanol. The supernatant will contain dialysable fraction. Complete precipitation of bound calcium is achieved by diluting the tissues twenty times with ethanol (Kannan & Ravindranath, 1980)

Biochemical Variability

A perusal of previous literature on the biochemistry of crustaceans would reveal a remarkable intra-specific variability in biochemical composition of tissues. A critical assessment of factors responsible for biochemical variability of tissues of individual species is necessary, in order to understand the physiological role of the biochemical components in question. Halberg (1973) has broadly classified the factors influencing individual biochemical variability as inter-individual and intraindividual. The inter-individual factors would include sex, size, moulting, nutritional and reproductive status in addition to pathological and environmental conditions. The intraindividual factors which may bring about biochemical variability include techniques and time of day

Population Structure of the Chenchu and Other South Indian Tribal Groups: Relationships between Genetic, Anthropometric, Dermatoglyphic, Geographic, and Linguistic Distances

This is the published version. Copyright 1994 Wayne State University Press.We describe the genetic structure and interrelationships of nine south Indian tribal groups (seven from Andhra Pradesh and two from the adjoining states of Tamil Nadu and Kerala) using seven polymorphic loci (ABO, MN, RH, PGM, ACP, PGD, and LDH). R matrix analysis indicates that the Andhra Pradesh tribes are clustered and that the Kadar and Irula are genetically isolated from them. This dispersion of populations has been explained by the combination of relatively high frequencies of the alleles RH D and MN M in the Kadar and the relatively high proportions of the allele PGM*2 in the Irula. The Mahaboobnagar Chenchu subgroup is isolated from other Telugu-speaking groups because of high frequencies of the PGM*1 and ACP*A alleles. The regression of mean per locus heterozygosity (//) on distance from the gene frequency centroid (r„) reveals considerable levels of external gene flow among the Lam-badi, the Yerukula, and the two Chenchu subgroups and more homogeneity in the Kolam, Koya, Yanadi, Irula, and Kadar. Mantel statistics were used to assess the relative effects of nonbiological processes (i.e., language and geography) on the morphological and genetic patterns of these subdivided populations. The significance of correlations was determined between different data sets (genetic, dermatoglyphic, anthropometric, geographic, and linguistic) at three levels involving nine, six, and five populations. Although multiple correlation analysis reveals significant combined effects of geography and language on genetics, anthropometrics, and dermato-glyphics, highly significant partial correlations suggest strong effects of geography on both anthropometry and genetics. Our analysis indicates that geographic factors have an overwhelming effect on the genetic differentiation of the south Indian tribal groups

Ammonia excretion and uptake

Ammonia is one of the major excretory products of. .aquatic crustaceans. The rate of ammonia excretion may reflect the activity of the animal (Subhashini, 1981). Ammonia excretion in crabs as well as in several isopods show diurnal variation (Kirby & Harbaugh, 1974; Subhashini, 1981). The amount of ammonia excreted by the animal can be determined by placing the animal in ammonia free artificial sea water, following the method as mentioned in 8.0. Crabs are known to take in" ammonia from the medium (Mangum & Towle, 1977 ; Subhashini, 1981)

Blood Volume

the principle underlying the methodology of blood volume determination involves the determination of degree of dilution of an injected dye by comparing the concentration of the injected dye and the concentration of the dye in the blood after a particular period of injection. The degree of dilution reflects blood volume (Lee, 1961)