Age-related changes in the translocation of phosphatidate phosphohydrolase from the cytosol to microsomal membranes in rat liver

The effects of oleate, spermine and chlorpromazine were assayed in the presence or absence of 0.15 M KCl on the translocation of phosphatidate phosphohydrolase activity from cytosol to endoplasmic reticulum membranes in liver homogenates obtained from rats aged 1, 30, 60, 180 and 360 days. Marked age-associated decreases in phosphatidate phosphohydrolase distribution onto the membranes were demonstrated under nearly all conditions. In liver homogenates taken from 1-day-old rats and incubated with 0.15 M KCl, most of the enzyme was active (associated with the membranes). Physiological salt concentration (0.15 M KCl) produced a 2-fold increase of oleate-induced translocation of phosphatidate phosphohydrolase activity in liver homogenates from 1-day-old rats; it had no effect on those from 60-day-old rats, and produced a notable decline in liver homogenates obtained from 180- and 360-day-old rats. The promoting effect of spermine on oleate-induced translocation of this enzyme activity was higher in younger rats when incubated in the absence of 0.15 M KCl. Chlorpromazine did not show its usual antagonizing effect on oleate-induced translocation of phosphatidate phosphohydrolase when added to homogenates taken from 1-day-old rats. The antagonizing effect was slightly apparent in liver homogenates from 30-day-old rats and was more pronounced in those from 60-day-old rats in which the values diminished to one-half and to one-third either in the presence or absence of 0.15 M KCl.     

Effect of rhodium (III) complex on experimental carcinogenesis in the livers of rats treated with thioacetamide

Enzyme activities and protein content were determined in the cytosolic and mitochondrial fractions of liver homogenates obtained from Rh(III) complex-, thioacetamide- and thioacetamide + Rh(III) complex-treated rats. The Rh(III) complex administered to nonthioacetamide-treated rats produced no significant changes either in the enzymatic activities assayed or in the protein concentration. The Rh(III) complex administered to thioacetamide-treated rats produced significant restoration of the following altered values: cytosolic and mitochondrial aspartate aminotransferase, glutamate dehydrogenase, NADP-isocitrate dehydrogenase, and protein concentration. However, a further increase was produced in the activities of glucose-6-phosphate dehydrogenase and malic enzyme. These increases can be interpreted in terms of an enhancement of the NADPH-dependent detoxifying processes and of nucleic acid synthesis and repair.     

Chaetomella acutiseta produces chaetomellic acids A and B which are reversible inhibitors of farnesyl-protien transferase

Chaetomellic acids A and B, isolated from Chaetomella acutiseta, are specific inhibitors of farnesyl-protein transferase that do not inhibit geranylgeranyl transferase type 1 or squalene synthase. Chaetomellic acids A and B are reversible inhibitors, resemble farnesyl diphosphate and probably inhibit FPTase by substituting for farnesyl diphosphate. Chaetomellic acid production appears to be widespread within the genus Chaetomella. Correspondence to: R. B. Lingham     

Genetic and environmental variability of adult size in some stocks of the edible snail, Helix aspersa

This paper aims at providing a better knowledge of factors determining body size (especially the importance of heredity) in Helix aspersa Müller.
A preliminary investigation of snails from Maghreb allowed us to show the importance of heredity in the variability of body size and to produce an efficient design for a subsequent reliable estimation of heritabilities. All traits measured (diameter, height and weight) were highly correlated and weight appeared to be the most convenient measure of size.
The second experiment provided 4150 snails born from known individuals among 500 wild snails. Pedigrees were recorded. Weight and diameter revealed high heritabilities (>0.4), which is relevant for commercial selection since variability of both traits was important. The design also revealed a significant non-genetic maternal effect and also that offspring from pairs where only one animal laid were bigger than offspring from pairs where both animals laid. This surprising observation has to be confirmed and its mechanisms studied.     

Wahrnehmungspsychologische Untersuchungen am EichelhÄher. II

Ohne Zusammenfassung     

Rab35: GEFs,GAPs and Effectors

Rabs are the largest family of small GTPases and are master regulators of membrane trafficking. Following activation by guanine‐nucleotide exchange factors (GEFs), each Rab binds a specific set of effector proteins that mediate the various downstream functions of that Rab. Then, with the help of GTPase‐activating proteins, the Rab converts GTP to GDP, terminating its function. There are over 60 Rabs in humans and only a subset has been analyzed in any detail. Recently, Rab35 has emerged as a key regulator of cargo recycling at endosomes, with an additional role in regulation of the actin cytoskeleton. Here, we will focus on the regulation of Rab35 activity by the connecdenn/DENND1 family of GEFs and the TBC1D10/EPI64 family of GTPase‐activating proteins. We will describe how analysis of these proteins, as well as a plethora of Rab35 effectors has provided insights into Rab35 function. Finally, we will describe how Rab35 provides a novel link between the Rab and Arf family of GTPases with implications for tumor formation and invasiveness .