Some Biochemical Abnormalities Caused by Cypermethrin in Adults of Tribolium castaneum (Herbst.)

Biochemical effects of sub lethal doses LC₁₀ and LC₂₀ of cypermethrin were studied on some enzymes and macromolecule activities of adult beetles of Tribolium castaneum (Herbst.). Cypermethrin caused disturbances in levels of all biochemical components under study. The dose of 0.78 ppm caused abnormalities in α‐amylase and FAA by increasing their activities i.e., 45.45% and 21.97% significantly. The higher sub lethal dose of 2.62 ppm disturbed all the parameters (AcP, α‐amylase, soluble protein and FAA) except AkP, which was decreased by 93.06%. Moreover, sub lethal doses either increased or decreased the levels of all parameters non‐significantly except AkP and FAA which were effected significantly by 87.92% and 14.29% at lower and higher doses, respectively. In the present studies, cypermethrin significantly enhanced the activity of AkP in both susceptible and resistant strains of T. castaneum adult beetles while FAA contents were increased significantly in resistant strain only. The activity of α‐amylase was significantly lowered in susceptible strain only.     

Molecular cloning and complete nucleotide sequence of the repeated unit and flanking gene of the scallop Pecten maximus mitochondrial DNA: Putative replication origin features

In the bivalve mollusc Pecten maximus, the size of the mitochondrial DNA molecules ranges from 20 to 25.8 kbp. This variability is mainly correlated with the occurrence of a variable domain composed with two to five 1.6-kbp repeated units tandemly arrayed in the genome. DNA fragments spanning the 1,586-base-pair-long repeated element and the nearest flanking gene have been cloned and sequenced. This sequence was analyzed regarding its base composition and potential secondary structures. The repeated unit domain was positioned and oriented with regard to the known flanking gene. It ends 2 base pairs upstream relative to the beginning of the tRNA^gly gene. The peculiar properties of the repeated unit were compared with those of the 1,442-bp repeated element found in the mitochondrial genome of the deep sea scallop Placopecten magellanicus. This comparison provided evidence for the absence of nucleotide conservation, except for a small sequence engaged in a secondary structure, but argued for a strong pressure maintaining domains with specific nucleotide content. A possible role for the conserved sequence is discussed.Correspondence to: A. Rigaa     

Native Enzyme Mobility Shift Assay (NEMSA): a new method for monitoring carboxyl group modification of carboxymethylcellulase from Aspergillus niger

A simple, sensitive, accurate and more informative assay for determining the number of modified groups during the course of carboxyl group modification is described. Monomeric carboxymethylcellulase (CMCase) from Aspergillus niger was modified by 1-ethyl-3(3-dimethylaminopropyl)carbodiimide (EDC) in the presence of glycinamide. The different time-course aliquots were subjected to non-denaturing PAGE and the gel stained for CMCase activity. The number of carboxyl groups modified are directly read from the ladder of the enzyme bands developed at given time. This method showed that after 75 min of modification reaction there were five major species of modified CMCases in which 6 to 10 carboxyls were modified.     

Cardiovascular adaptations to 10days of cycle exercise

Mier, Constance M., Michael J. Turner, Ali A. Ehsani, andRobert J. Spina. Cardiovascular adaptations to 10 days of cycleexercise. J. Appl. Physiol. 83(6):1900-1906, 1997.We hypothesized that 10 days of training wouldenhance cardiac output (CO) and stroke volume (SV) during peak exerciseand increase the inotropic response to -adrenergic stimulation. Tensubjects [age 26 ± 2 (SE) yr] trained on a cycleergometer for 10 days. At peak exercise, training increasedO₂ uptake, CO, and SV(P < 0.001). Left ventricular (LV)size and function at rest were assessed with two-dimensional echocardiography before (baseline) and after atropine injection (1.0 mg) and during four graded doses of dobutamine. LV end-diastolic diameter increased with training (P < 0.02), whereas LV wall thickness was unchanged. LV contractileperformance was assessed by relating fractional shortening (FS) to theestimated end-systolic wall stress(_ES). Training increased theslope of the FS-_ES relationship (P < 0.05), indicating enhancedsystolic function. The increase in slope correlated with increases inCO (r = 0.71,P < 0.05) and SV(r = 0.70,P < 0.05). The increase in bloodvolume also correlated with increases in CO(r = 0.80, P < 0.01) and SV (r = 0.85, P < 0.004). These datashow that 10 days of training enhance the inotropic response to-adrenergic stimulation, associated with increases in CO and SVduring peak exercise.

     

Ataxia with Vitamin E Deficiency: Refinement of Genetic Localization and Analysis of Linkage Disequilibrium by Using New Markers in 14 Families

Ataxia with vitamin E deficiency (AVED) is an autosomal recessive disease characterized clinically by neurological symptoms with often striking resemblance to those of Friedreich ataxia. This disorder has been reported previously as familial isolated vitamin E deficiency. We have mapped recently the AVED locus to a 5-cM confidence interval on chromosome 8q by homozygosity mapping in six Mediterranean families. We have now analyzed six new and two previously described families and demonstrate genetic homogeneity despite important clinical variability and wide geographic origins. Analysis of nine new tightly linked microsatellite markers, including four characterized in this study, revealed a predominant but not unique mutation in northern African populations, where this condition is more frequent. Haplotype analysis but also classical recombinations allowed us to refine the AVED position to a 1-cM interval. A YAC contig over this interval was constructed from marker STSs and YAC fingerprint data, in order to facilitate the search of the AVED gene.     

Benthic foraminiferal fauna during the time of the Indian-Asian contact, in southern Balochistan, Pakistan

Cretaceous and early Paleocene benthic foraminifera were studied from one section along the western Gaj River, southern Balochistan, Pakistan, to reconstruct the paleoenvironment of the Tethys Sea during the Indian-Asian contact. We recognize three lithostratigraphic units in ascending order: the Mughal Kot Formation, the Pab Sandstone, and the Jamburo Group. Both the Maastrichtian Mughal Kot Formation, which consists of shale with grey marly limestone, and the Maastrichtian Pab Sandstone, which consists of quartzose sandstone, indicate an open ocean environment as they have diversified planktic and benthic foraminiferal assemblages. The Maastrichtian-Paleocene Jamburo Group, consisting of dark grey, calcareous shale and marlstone with some sulfide grains, is characterized by low diversities of benthic assemblages. The change to the lower diversities may be associated with the development of poor circulation of deeper water that was caused by narrowing of the Tethys Sea.The Trochammina spp. Assemblage from the Jamburo Group, which can be correlated with flysch-type agglutinated foraminiferal assemblages, has a low benthic species diversity, indicating an unfavorable condition for calcareous foraminifera because of the development of oxygen-depleted water. The absolute abundance of agglutinated specimens shows a remarkable change from low numbers in the Maastrichtian to high ones in the Paleocene. The benthic foraminiferal evidence supports the hypothesis that the collision of the Asian and Indian plates occurred near the end of the Cretaceous.