Thin-layer chromatography of aluminium: quantitative densitometric determination of Fe2+, Ni2+, Cu2+, and Si4+.

Thin-layer chromatography in combination with scanning densitometry is used as a tool for the quantitative determination of some impurity and additive elements in aluminium. Microgram levels of iron, silicon, copper, nickel, titanium, magnesium, manganese, and zinc present in a high concentration aluminium matrix is detected, and selective separations of some of these elements are achieved on silica gel H layers developed with a mobile phase containing aqueous sodium chloride solution. The quantitative determination of iron, silicon, nickel, and copper are obtained from the densitometric evaluation of chromatograms and are compared with the respective optical emission spectral analytical data.

Thin layer chromatographic study of bauxite and quantitative estimation of co-existing Al3+, Fe2+ and Ti4+.

Thin layer chromatography in combination with spectrophotometry and titrimetry has been used to evaluate chromatographic characteristics of bauxite constituents. The retention behaviors of four major constituents (Al3+, Fe2+, Ti4+, Si4+) in bauxite mineral have been examined on plain and modified layers of silica gel G, silica gel H and cellulose with mobile phases containing aqueous sodium chloride, formic acid and hydrochloric acid. Ternary separation of Al-Fe-Ti was achieved on chromatographic plates made of silica gel H. The pH effect and presence of impurity elements in samples, nature of stationary phases on the ternary separation and detection limits of bauxite constituents were studied. Silicon in bauxite was detected on cellulose plates. Quantitative determinations of Al3+, Fe2+ and Ti4+ on silica gel H impregnated with sodium formate layers were achieved by titrimetry and spectrophotometry.

Studies on some kinetic parameters of aldolases in selected tissues of the freshwater fish (Tilapia mossambica) under the toxic impact of methyl parathion.

Kinetic parameters of aldolases in muscle, gill, liver and brain tissues of the teleost Tilapia mossambica were studied at sublethal concentrations with methyl parathion (MP). The pH activity profiles were optimal at pH 7.0 and 9.0 in gill, liver and brain tissues, whereas only a single peak at pH 7.0 was observed in muscle tissue of both control and MP-exposed fish. The pH 7.0-specific peak was confirmed as aldolase A and the pH 9.0-specific peak represents the tissue-specific aldolases: aldolase B in liver, aldolase C in brain and aldolase B-C in gill. It is further confirmed with the inhibitor sensitivity of aldolases at two peaks with 6 x 10(-3) M ATP or AMP. The pH-based substrate-dependent kinetics of aldolases showed a variable trend. The tissue-specific activity of pH 7.0-specific aldolases showed low Km values for gill followed by muscle, liver and brain tissues, suggestive of its high enzyme-substrate affinity. During MP exposure, the Vmax values of pH 7.0-specific aldolases in muscle, gill and brain were unchanged compared to controls, but Km values were decreased. The pH 9.0-specific aldolases of gill and liver from MP-exposed fish showed decreased Km values with a slight increase in Vmax values. Effectors such as lysine, arginine and Ca2+ inhibited, while histidine, cysteine, aspartic acid and alpha-ketoglutaric acid elevated the activity levels of aldolases.(ABSTRACT TRUNCATED AT 250 WORDS)

Methyl parathion (O-O-dimethyl O-4-nitrophenyl thiophosphate) effects on whole-body and tissue respiration in the teleost, Tilapia mossambica (Peters).

The respiratory parameters of a freshwater teleost, Tilapia mossambica Peters, were studied under sublethal intoxication of methyl parathion. The rate of oxygen consumption by whole fish and selected tissues decreased during a 48-hr time-course study. The activities of the respiratory enzymes succinate dehydrogenase, malate dehydrogenase, and cytochrome-c oxidase also decreased considerably under methyl parathion exposure in muscle, gill, liver, and brain tissues. These results suggest that methyl parathion has a profound effect on the oxidative metabolism of the fish which results in low ATP turnover, possibly due to its influence on the respiratory center of the brain.

Impact of methyl parathion toxicity and eserine inhibition on acetylcholinesterase activity in tissues of the teleost (Tilapia mossambica)--a correlative study.

Acetylcholinesterase (AChE) activity and acetylcholine (ACh) content of muscle, gill, liver and brain tissues of control and methyl parathion-exposed (MPE) fish were determined. In addition, in vitro concentrations of eserine necessary to produce inhibition of AChE equivalent to in vivo inhibition by sublethal amounts of methyl parathion (MP) were also investigated. AChE activity decreased in all tissues, while ACh content showed a corresponding increase. These observations indicate disruption of nerve impulse conduction. The in vitro effect of eserine on AChE activity differed with the type of MP action. These results are discussed in relation to the sensitivity and extent of innervation of various tissues.

Changes in the tissue lipid profiles of fish (Oreochromis mossambicus) during methyl parathion toxicity--a time course study.

The levels of total lipids, phospholipids, free fatty acids and total cholesterol were studied in selected tissues of the fish, Oreochromis mossambicus under sublethal stress of methyl parathion for 48 h. The levels of total lipids and phospholipids decreased while the free fatty acids and total cholesterol levels increased during the exposure period. These results are discussed in relation to induced gluconeogenesis and the diversion of acetyl CoA to cholesterol synthesis during methyl parathion intoxication.

Tissue specific alteration of aminotransferases and total ATPases in the fish (Tilapia mossambica) under methyl parathion impact.

The activity levels of aspartate aminotransferase (AAT), alanine aminotransferase (AlAT) and total adenosine triphosphatase (ATPase) were studied in muscle, gill, liver and brain tissues of control and methyl parathion exposed (MPE) fish. Both aminotransferases were elevated in all the tissues inferring the diversion of alpha-amino acids into the TCA cycle as keto acids to augment energy production during methyl parathion (MP) stress. In gill, liver and brain tissues, there seemed to be a shift in the aminotransferase reactions under MP impact. The total ATPase activity was decreased in all tissues, suggesting inhibition of active transport and oxidative phosphorylation.

Sublethal toxicity of malathion on the proteases and free amino acid composition in the liver of the teleost, Tilapia mossambica (Peters).

Exposure of fish to a sublethal concentration of malathion showed a significant inhibition of acetylcholinesterase (AChE) activity. The levels of protease were markedly elevated with a consequent increase in most of the free amino acids. However, the levels of glutamic acid and valine, phenylalanine and methionine complex remained unchanged, while aspartic acid showed a marked drop. These changes are discussed in relation to the sublethal stress induced by malathion.

Distribution of middle phalangeal hair in the two groups of Srivaishnava Brahmins of Tirupati (South India).

400 adult unrelated individuals of both sexes were studied from two groups of Srivaishnava Brahmins residing in Tirupati, South India, for the distribution of middle phalangeal hair (MPH). The occurrence of MPH was predominantly manifested on the III, IV, and V digits of both hands in the two sexes of Vadagalai and Tengalai groups. Tengalai males showed higher frequency of presence of MPH (39.00%) than Vadagalai males (37.00%). Among the females the frequency was (36.00 %) in Tengalai and (34.00 %) in Vadagalai groups. Sex differences were not statistically significant in both the groups. Populations of Mongoloid affinity seems to have a marked increase in the frequency of individuals without MPH and the present Srivaishnava Brahmin sample reflects such a similar tendency.