Decline in photopositive tendencies with age inDrosophila melanogaster (Diptera: Drosophilidae)

Phototaxis was measured in young, middle-aged, and oldDrosophila melanogaster flies of both sexes. The apparatus allowed us to measure the tendency to go toward light, independently of the time needed to do so; under such conditions, phototaxis is dissociated from locomotor activity. The percentage of photopositive flies decreased slightly with age (93.96, 80.17, and 78.97%, respectively, in young, middle-aged, and old flies). Results are discussed in connection with previous data for which the tendency to go toward light and the time to do so were not dissociated.     

Congenital defects of the upper lateral incisors (ULI): Condition and measurements of the other teeth,measurements of the superior arch,head and face

We surveyed a French male population for the incidence of missing or reduced upper lateral incisors (ULI). In 5,738 subjects, we observed an incidence of 1.59% with one or two reduced ULI (the other normal) and 1.90% with one or two missing ULI (the other normal or reduced), altogether, 3.49% affected subjects. Furthermore, 250 random controls were observed. Agenesis of other teeth is more frequent in propositi. Missing third molars were 12.4% in controls, 24.0% in propositi with reduced ULI and 39.6% in propositi with two missing ULI. Furthermore, agenesis of incisors, canines and premolars ranges from 0.4% in controls to 1.3% in propositi having reduced ULI and 5.0% in propositi with two missing ULI. So, propositi with reduced ULI are intermediate between the controls and the propositi with missing ULI with respect to the frequency of agenesis of other teeth. On the other hand, a different ranking is observed with respect to the teeth measurements: reduction of tooth size is more marked in propositi with reduced ULI than in propositi with missing ULI. The reduction mainly affects canines, incisors and to a lesser degree, premolars. Arch length and interpremolar diameters are smaller in propositi with missing ULI, compared with controls.     

Cholelithiasis in a male rhesus monkey (Macaca mulatta) fed a cholesterol-containing diet.

In this report we describe the development of cholelithiasis in a male rhesus monkey fed a cholesterol-containing diet for 24 months. This represents the only case of cholelithiasis in this species of nonhuman primate that we have observed out of a population of over 500 rhesus monkeys fed similar cholesterol-containing diets. Associated with the appearance of gallstones was the production of bile saturated with cholesterol, and the excretion of bile with an abnormal bile acid composition.     

Experiments on effects of phosphorus on the manganese nutrition of plants

Summary Monocalcium phosphate (MCP), the salt of concentrated superphosphate, applied to a Buganda soil increased the amount of manganese taken up by ryegrass. To investigate the cause of this effect the derivatives of MCP hydrolysis, dicalcium phosphate (DCP) and triple-point solution (TPS) were separated and applied independently. Both derivatives, and a synthetic dicalcium phosphate dihydrate, increased the concentration of manganese in ryegrass showing that dissolution of soil manganese by TPS (pH 1.48) was not a unique cause.DCP derived by hydrolysis of MCP supplied little phosphorus to early crops of ryegrass but a larger proportion of its P was taken up by later crops; TPS supplied more of its P to earlier than to later crops. During 42 weeks the proportions of P taken up from DCP and TPS were similar to the proportions of phosphorus in these forms when MCP hydrolyzes.Phosphorus in DCP derived by hydrolysis of MCP was more available to ryegrass than phosphorus in a synthetic dicalcium phosphate dihydrate, showing that results may be misleading when synthetic materials are used to simulate the compounds that form from fertilizers in soil. re]19760401     

Influence of thyroparathyroidectomy and thyroxine replacement on CU and ZN cellular distribution and on the metallothionein level and induction in rats

Thyroid hormones are involved in copper and zinc distribution in rat tissues. We examined the influence of thyroparathyroidectomy (TPTY) and of a replacement therapy by T4 on Cu and Zn organ distribution. MT levels were also measured both in basal conditions and after induction by cadmium. The results confirm that a lack of T4 modified Cu and Zn in serum and tissues. In serum, TPTY increased Cu (+15%) and ceruloplasmin (+18%), and decreased Zn (−18%). In tissues, Cu was altered in liver (+13%), kidney (−24%), heart (−16%) duodenum (−18%), and Zn in liver (+25%) and kidney (−10%). The soluble fractions (100,000 g supernatant) were mainly affected in liver and kidney, and the subcellular fractions in heart and duodenum. MT levels were modified in basal conditions only in liver (+57%) and kidney (−36%). T4 administration partially prevented the effect of TPTY on both elements and MT concentrations. Therefore, no evidence is provided for a direct role of T4 in the metabolism of MT in a way comparable to the effects of glucocorticoids. However, MT could mediate the consequences of TPTY on metal distribution in certain organs, such as liver and kidney.     

Characterization of a major brain tubulin variant which cannot be tyrosinated

Brain tubulin preparations contain an abundant type of tubulin which does not undergo the normal cycle of tyrosination-detyrosination, and whose nature is still unknown. We have used peptide sequence analysis and mass spectrometry combined with immunological procedures to show that this non-tyrosinatable tubulin has a specific primary structure. It differs from the tyrosinated isotype in that it lacks a carboxy-terminal glutamyl-tyrosine group on its alpha-subunit. Thus, non-tyrosinatable tubulin originates from a well-defined posttranslational modification of the tubulin primary structure which is located at the expected site of activity of tubulin tyrosine ligase. This probably accounts for the reason why it cannot be tyrosinated. The significance of this abundant brain isotubulin and the metabolic pathway involved in its formation remain to be elucidated. This should shed light on the relation between the structural diversity of the carboxy terminus of alpha-tubulin and the regulation of functional properties of microtubules.     

In vivo clearance of low-density lipoproteins and beta-very-low-density lipoproteins in normal and hypercholesterolemic White Carneau pigeons

Low-density lipoproteins (hLDL) and beta-migrating-very-low-density lipoproteins (beta-VLDL) were isolated from the plasma of cholesterol-fed White Carneau (WC) pigeons and low-density lipoproteins (nLDL) were isolated from the plasma of grain-fed WC pigeons. The lipoproteins were radiolabeled with 125I or 131I and injected into normocholesterolemic or hypercholesterolemic WC pigeons to determine their rate of clearance from the plasma. The fractional catabolic rate (FCR) of nLDL and hLDL in normocholesterolemic pigeons averaged 0.202 and 0.206 pools/h.respectively. beta-VLDL was cleared at a significantly slower rate of 0.155 pools/h. The FCR of the same lipoproteins injected into hypercholesterolemic pigeons was reduced by 17% for nLDL, 50% for hLDL and 57% for beta-VLDL, indicating that the effect of hypercholesterolemia on clearance in vivo was different for the three lipoproteins. The FCR of reductively methylated pigeon LDL (MeLDL), which gives a measure of receptor-independent clearance of LDL, was shown previously to be 0.037 pools/h. These studies suggest therefore that LDL and beta-VLDL are cleared from the plasma of normocholesterolemic and hypercholesterolemic pigeons at a rate substantially greater than that predicted for non-specific processes. Despite the reduction in the clearance rate of hLDL and beta-VLDL due to cholesterol feeding, the absolute amount of cholesterol that was cleared from the plasma by these lipoproteins was increased from approx. 200 mg/kg body weight per day in the normocholesterolemic pigeons to greater than 1000 mg/kg body weight per day in the hypercholesterolemic pigeons. This is due principally to the enrichment in cholesterol relative to protein of the lipoproteins isolated from cholesterol-fed pigeons and the failure of hypercholesterolemia to completely inhibit receptor-dependent clearance of LDL and beta-VLDL. The lower rate of clearance of beta-VLDL relative to LDL is in marked contrast to mammalian beta-VLDL, which is cleared much faster than LDL, but is consistent with the lack of apo E on pigeon lipoproteins. Apo E is the apoprotein that is thought to be responsible for the rapid clearance of beta-VLDL in normocholesterolemic mammals. The low rate of beta-VLDL clearance in pigeons also suggests that pigeons lack an apolipoprotein that function like mammalian apo E.     

A METHOD FOR ESTIMATING MASS OF LARGE PINNIPEDS

Fifty-two male elephant seals were weighed and photographed at Año Nuevo State Reserve, California, to establish a predictive relationship between photographically measured morphological variables (length, side area, and girth area) and body mass. Regression of mass on these variables revealed that side area, roughly equivalent to a longitudinal cross-section, was the most useful single variable for predicting mass, and that adding the other two variables to side area slightly improved the accuracy of the photogrammetric technique. Curvilinear regressions based on a power model provided the best predictive relationships. This technique may prove useful for estimating body mass of other pinnipeds.