Tryptophan Hydroxylase Is Phosphorylated by Protein Kinase A

Abstract: The effect of protein kinase A on the catalytic activity and phosphorylation of brain tryptophan hydroxylase was examined. Stimulation of endogenous protein kinase A by cyclic AMP or its analogues, dibutyryl-cyclic AMP and 8-thiomethyl-cyclic AMP, failed to activate tryptophan hydroxylase. The activation of tryptophan hydroxylase by calcium/calmodulin-phosphorylating conditions was not modified by cyclic AMP. Endogenous protein kinase A phosphorylated a large number of proteins and tryptophan hydroxylase could be identified as one substrate by sucrose gradient centrifugation, immunoprecipitation, and immunoblotting. These results indicate that tryptophan hydroxylase is phosphorylated by protein kinase A in brain and question whether this protein kinase exerts direct regulatory influence over tryptophan hydroxylase activity via phosphorylation.     

Synthesis of novel substituted pyrimidine derivatives bearing a sulfamide group and their in vitro cancer growth inhibition activity

The synthesis of two series of novel substituted pyrimidine derivatives bearing a sulfamide group have been described and their in vitro cancer growth inhibition activities have been evaluated against three human tumour cell lines (HT-29, M21, and MCF7). In general, growth inhibition activity has been enhanced by the introduction of a bulky substituent on the aromatic ring with the best compound having GI₅₀ < 6 μM for all the human tumour cell lines. The MCF7 selective compounds were evaluated on four additional human invasive breast ductal carcinoma cell lines (MDA-MB-231, MDA-MB-468, SKBR3, and T47D) and were selective against T47D cell line in all cases except one, suggesting a potential antiestrogen activity.     

Neuronal non-CG methylation is an essential target for MeCP2 function

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How Predictability of Feeding Patches Affects Home Range and Foraging Habitat Selection in Avian Social Scavengers?

Feeding stations are commonly used to sustain conservation programs of scavengers but their impact on behaviour is still debated. They increase the temporal and spatial predictability of food resources while scavengers have supposedly evolved to search for unpredictable resources. In the Grands Causses (France), a reintroduced population of Griffon vultures Gyps fulvus can find carcasses at three types of sites: 1. “light feeding stations”, where farmers can drop carcasses at their farm (spatially predictable), 2. “heavy feeding stations”, where carcasses from nearby farms are concentrated (spatially and temporally predictable) and 3. open grasslands, where resources are randomly distributed (unpredictable). The impact of feeding stations on vulture’s foraging behaviour was investigated using 28 GPS-tracked vultures. The average home range size was maximal in spring (1272±752 km²) and minimal in winter (473±237 km²) and was highly variable among individuals. Analyses of home range characteristics and feeding habitat selection via compositional analysis showed that feeding stations were always preferred compared to the rest of the habitat where vultures can find unpredictable resources. Feeding stations were particularly used when resources were scarce (summer) or when flight conditions were poor (winter), limiting long-ranging movements. However, when flight conditions were optimal, home ranges also encompassed large areas of grassland where vultures could find unpredictable resources, suggesting that vultures did not lose their natural ability to forage on unpredictable resources, even when feeding stations were available. However during seasons when food abundance and flight conditions were not limited, vultures seemed to favour light over heavy feeding stations, probably because of the reduced intraspecific competition and a pattern closer to the natural dispersion of resources in the landscape. Light feeding stations are interesting tools for managing food resources, but don’t prevent vultures to feed at other places with possibly high risk of intoxication (poison).     

Spectroscopic characterization of the light-harvesting complex of Rhodospirillum rubrum and its structural subunit

The spectroscopic properties of the light-harvesting complex of Rhodospirillum rubrum, B873, and a detergent-isolated subunit form, B820, are presented. Absorption and circular dichroism spectra suggest excitonically interacting bacteriochlorophyll alpha (BChl alpha) molecules give B820 its unique spectroscopic properties. Resonance Raman results indicate that BCHl alpha is 5-coordinate in both B820 and B873 but that the interactions with the BChl C2 acetyl in B820 and B873 are different. The reactivity of BChl alpha in B820 in light and oxygen, or NaBH4, suggests that it is exposed to detergent and the aqueous environment. Excited-state lifetimes of the completely dissociated 777-nm-absorbing form [1.98 ns in 4.5% octyl glucoside (OG)], the intermediate subunit B820 (0.72 ns in 0.8% OG), and the in vivo like reassociated B873 (0.39 ns in 0.3% OG) were measured by single-photon counting. The fluorescence decays were exponential when emission was detected at wavelengths longer than 864 nm. An in vivo like B873 complex, as judged by its spectroscopic properties, can be formed from B820 without the presence of a reaction center.     

Regulation of the autophagy initiating kinase ULK1 by nutrients: Roles of mTORC1 and AMPK

Comment on: Kim J, et al. Nat Cell Biol 2011; 13:132-41.     

The reproductive biology of the Rock Partridge Alectoris graeca saxatilis in the southern French Alps: first evidence of double-nesting behaviour

Capsule: Double-nesting occurs frequently in Rock Partridges Alectoris graeca living in the southern French Alps.

Aims: To investigate reproductive parameters of a Rock Partridge Alectoris graeca population.

Methods: The reproductive behaviour of 62 radio-tagged birds was monitored during the breeding seasons 2012–16, to record breeding phenology, clutch sizes, hatching success, nest survival and parental care.

Results: Double-nesting behaviour in the Rock Partridge was confirmed for the first time. Participation in incubation was similar for males and females (86% versus 70%). Clutch size was larger for nests incubated by males (11.0?±?1.6 eggs) than by females (9.5?±?1.2). Male nest survival rate (0.37) tended to be lower than female nest survival rate (0.62), although the difference was not significant. No significant difference was detected between male and female hatching success. Nest failures were caused by mammals taking the eggs (78%) or predation of the incubating parent (13%). Some circumstantial evidence suggests that occurrence of double-nesting behaviour could depend on previous winter and spring weather influencing the body condition of females. The reproductive biology of the Rock Partridge contrasts in some breeding traits with Red-legged Partridge and natural partridge hybrids, possibly due to climatic differences between habitats.

Conclusion: Confirmation of double-nesting in Rock Partridges indicates that climatic constraints inherent to its mountain environment do not act as an impediment to this behaviour. Variation in weather conditions between years could influence the annual occurrence of double-nesting.