Increased size due to larval royal jelly exposure does not affect circadian locomotor activity or climbing ability in adult female Drosophila melanogaster

The effects of royal jelly (RJ) appear to be conserved in Drosophila; flies exposed of RJ exhibit increased body size, similar to queen bees. However, in flies and bees, there is evidence that increased body size can lead to impairments to locomotor activity, while RJ may have anti-fatigue properties. Canton-S and Oregon-R Drosophila larvae were raised on media containing 0% or 20% pure RJ. Climbing assays were conducted to assess vertical locomotion. Circadian locomotion was observed using Drosophila Activity Monitors. CS, but not Or-R, raised on RJ were larger compared to controls. Flies exposed to RJ exhibited entrainment and free-running rhythms. The increased size due to RJ exposure in this study had no bearing on circadian locomotor activity or climbing. These results indicate that there is variation among physiological responses to RJ among different strains, but RJ was equally ineffective in affecting locomotor behavior no matter the physiological response.     

The glucocorticoid receptor recruits the COMPASS complex to regulate inflammatory transcription at macrophage enhancers

1. Download : Download high-res image (131KB)
2. Download : Download full-size image

     

Long-term wheel-running and acute 6-h advances alter glucose tolerance and insulin levels in TALLYHO/JngJ mice

Studies have shown a relationship between circadian rhythm disruptions and type-2 diabetes. This investigation examined the effects of circadian disruption (6-h phase advances) on the progression of diabetes in a type-2 diabetic mouse model –TALLYHO/JngJ – and whether wheel-running can alleviate the effects of the phase advances. 6-h advances alter fasting glucose, glucose tolerance and insulin production. Wheel-running reduced body mass, improved glucose tolerance and reduced insulin in TALLYHO/JngJ and alleviated some of the changes in diabetic symptoms due to 6-h advances. These results indicate that individuals with type-2 diabetes can benefit from physical activity and exercise can be a countermeasure to offset the effects of an acute phase advance.     

Taxonomic distinctness indices for discriminating patterns in freshwater rotifer assemblages

Taxonomic distinctness indices measure the taxonomic relatedness among species and have been used for environmental assessment to detect disturbed habitats. This is the first application of the Average Taxonomic Distinctness (Δ⁺) and Variance in Taxonomic Distinctness (Λ⁺) indices to the presence/absence data of rotifer communities to examine their sensitiveness in discriminating perturbed environments. The 26 Greek lakes studied spanned a wide range of morphological and physical–chemical characteristics. Δ⁺ was significantly correlated (P < 0.05) with maximum depth, salinity and trophic state, while Λ⁺ was correlated only with salinity. The index Δ⁺ identified lakes characterized by periods of increased salinity. Communities in these lakes were less diverse, consisting of more closely related species as seen by the reduced number of families than other lakes with similar species richness. Lakes identified by Λ⁺ had a higher community distinctness than expected due to the overrepresentation of the family Brachionidae; they were also characterized by periods of water-level fluctuations. Both indices were unaffected by sampling effort in terms of number of species and sampling visits; whereas Shannon diversity index (H′) was correlated to species number. Also, based on the randomization test, the taxonomic distinctness indices differentiated lakes anthropogenically disturbed based on the expected patterns of diversity of the area.

     

Raman 18O-labeling of bacteria in visible and deep UV-ranges

Raman stable isotope labeling with ²H, ¹³C or ¹⁵N has been reported as an elegant approach to investigate cellular metabolic activity, which is of great importance to reveal the functions of microorganisms in native environments. A new strategy termed Raman ¹⁸O-labeling was developed to probe the metabolic activity of bacteria. Raman ¹⁸O-labeling refers to the combination of Raman microspectroscopy with ¹⁸O-labeling using H₂¹⁸O. At an excitation wavelength of 532 nm, the incorporation of ¹⁸O into the amide I group of proteins and DNA/RNA bases was observed in Escherichia coli cells, while for an excitation wavelength electronically resonant with DNA or aromatic amino acid absorption at 244 nm ¹⁸O assimilation was detected using chemometric tools rather than visual inspection. Raman ¹⁸O-labeling at 532 nm combined with 2D correlation analysis confirmed the assimilation of ¹⁸O in proteins and nucleic acids and revealed the growth strategy of E. coli cells; they underwent protein synthesis followed by nucleic acid synthesis. Independent cultural replicates at different incubation times corroborated the reproducibility of these results. The variations in spectral features of ¹⁸O-labeled cells revealed changes in physiological information of cells. Hence, Raman ¹⁸O-labeling could provide a powerful tool to identify metabolically active bacterial cells.     

The ultrastructure of Chlorobaculum tepidum revealed by cryo-electron tomography

Chlorobaculum (Cba) tepidum is a green sulfur bacterium that oxidizes sulfide, elemental sulfur, and thiosulfate for photosynthetic growth. As other anoxygenic green photosynthetic bacteria, Cba tepidum synthesizes bacteriochlorophylls for the assembly of a large light-harvesting antenna structure, the chlorosome. Chlorosomes are sac-like structures that are connected to the reaction centers in the cytoplasmic membrane through the BChl α-containing Fenna–Matthews–Olson protein. Most components of the photosynthetic machinery are known on a biophysical level, however, the structural integration of light harvesting with charge separation is still not fully understood. Despite over two decades of research, gaps in our understanding of cellular architecture exist. Here we present an in-depth analysis of the cellular architecture of the thermophilic photosynthetic green sulfur bacterium of Cba tepidum by cryo-electron tomography. We examined whole hydrated cells grown under different electron donor conditions. Our results reveal the distribution of chlorosomes in 3D in an unperturbed cell, connecting elements between chlorosomes and the cytoplasmic membrane and the distribution of reaction centers in the cytoplasmic membrane.