Light Stimuli and Circadian Clock Affect Neural Development in .

Endogenous clocks enable organisms to adapt cellular processes, physiology, and behavior to daily variation in environmental conditions. Metabolic processes in cyanobacteria to humans are under the influence of the circadian clock, and dysregulation of the circadian clock causes metabolic disorders. In mouse and , the circadian clock influences translation of factors involved in ribosome biogenesis and synchronizes protein synthesis.

RSK Influences the Pace of the Circadian Clock by Negative Regulation of Protein Kinase Shaggy Activity.

Endogenous molecular circadian clocks drive daily rhythmic changes at the cellular, physiological, and behavioral level for adaptation to and anticipation of environmental signals. The core molecular system consists of autoregulatory feedback loops, where clock proteins inhibit their own transcription. A complex and not fully understood interplay of regulatory proteins influences activity, localization and stability of clock proteins to set the pace of the clock.

Drosophila mbm is a nucleolar myc and casein kinase 2 target required for ribosome biogenesis and cell growth of central brain neuroblasts.

Proper cell growth is a prerequisite for maintaining repeated cell divisions. Cells need to translate information about intracellular nutrient availability and growth cues from energy-sensing organs into growth-promoting processes, such as sufficient supply with ribosomes for protein synthesis. Mutations in the mushroom body miniature (mbm) gene impair proliferation of neural progenitor cells (neuroblasts) in the central brain of Drosophila melanogaster.

Structural brain mutants: mushroom body defect (mud): a case study.

Single-gene mutants of Drosophila have not only increased our understanding of the biochemical processes underlying learning and memory processes, but also established structure-function relationships. The first relevant mutants were identified by Martin Heisenberg nearly 30 years ago in a screen for altered adult brain structure and were used to link the mushroom bodies in the central brain with olfactory learning and memory processes. Because the observed structural defects in the adult are the consequence of deregulated developmental processes, the characterization of these mutants can also provide insight into the genetic programs underlying the establishment, maintenance, and remodeling of functional neuronal circuits.

Reproductive success in two species of desert fleas: density dependence and host effect.

We tested the hypothesis that a negative fitness-density relationship exists in haematophagous ectoparasites. We studied the effect of flea density on the number of blood meals necessary for starting oviposition and egg production in Xenopsylla conformis and Xenopsylla ramesis when exploiting two rodent hosts, Meriones crassus and Gerbillus dasyurus. The number of blood meals taken by a flea prior to first oviposition was similar in both flea species but was dependent on flea density and differed significantly between hosts.