Light-induced switching of HAMP domain conformation and dynamics revealed by time-resolved EPR spectroscopy

HAMP domains are widely abundant signaling modules. The putative mechanism of their function comprises switching between two distinct states. To unravel these conformational transitions, we apply site-directed spin labeling and time-resolved EPR spectroscopy to the phototactic receptor/transducer complex NpSRII/NpHtrII. We characterize the kinetic coupling of NpHtrII to NpSRII along with the activation period of the transducer and follow the transient conformational signal. The observed transient shift towards a more compact state of the HAMP domain upon light-activation agrees with structure-based calculations. It thereby validates the two modeled signaling states and integrates the domain’s dynamics into the current model.     

Spatial distribution patterns of the hyporheic invertebrate communities in a polluted river in Romania

The purpose of this study was to examine the sensitivity, in a field situation, of the hyporheic fauna to pollution by heavy metals and also to test the use of oxidative stress enzymes produced by this fauna as a sensitive indicator of oxidative stress generated by chemical contamination. This was done by surveying the patterns of distribution, structure, and composition of hyporheic invertebrate communities in one of the most polluted rivers in Romania. Twelve permanent sampling stations with differing water qualities were established along a 180 km transect of the Arie? River. Data on hyporheic invertebrate abundance and richness, chemistry of the surface and hyporheic water and interstitial suspended particles were analyzed via multifactorial analyses. In the downstream, more polluted stations, epigean species were less abundant and hyporheic communities, especially macrocrustaceans and oligochetes, became dominant. The higher levels of hyporheic invertebrate biodiversity in the moderately polluted stations compared to highly polluted, and the increase of the number of some hyporheos (especially macrocrustaceans) in the moderately polluted stations, suggested that the hyporheic fauna was more tolerant of heavy metal pollution than the surface water fauna of the area. However, the different richness and abundance of hyporheic fauna in sites of similar water chemistry suggested that additional factors, such as sediment structure are shaping the spatial distribution of hyporheic fauna. Strong correlations between superoxide dismutase (SOD) activity in pooled tissues extracts and some chemical parameters suggest that oxidative stress enzymes may prove to be sensitive indicators of chemical pollution in hyporheic zones.     

Remarks on the Permian dasycladalean alga Sinoporella leei Yabe, 1949

Sinoporella leei was first described and illustrated by Yabe in 1949 as a new species and was ascribed to a new subgenus of the genus Triploporella (Steinmann). This alga was not illustrated again until Mu published 25-years later a photomicrograph of a longitudinal-tangential section. The recent finding of new specimens in Permian strata of the Guangxi region (South China) allows us to better illustrate this alga, and to improve our understanding of its morphology to the extent that we find it necessary to emend the current diagnosis. The new observations focus mainly on the morphology of the second-order laterals, on their relationship to the first-order laterals, and the connection of the first-order laterals to the main stem. These data suggest that Sinoporella represents a self-standing, discrete genus that differs from Triploporella. We also consider the lack of cystophores (cyst containers sensu De Castro) and the possible occurrence of individual cysts in the first order laterals as characteristics that do not accord with Barttolo's emended diagnosis of Triploporella.     

Juvenile hormone pathway in honey bee larvae: A source of possible signal molecules for the reproductive behavior of Varroa destructor

The parasitic mite Varroa destructor devastates honey bee (Apis mellifera) colonies around the world. Entering a brood cell shortly before capping, the Varroa mother feeds on the honey bee larvae. The hormones 20‐hydroxyecdysone (20E) and juvenile hormone (JH), acquired from the host, have been considered to play a key role in initiating Varroa''s reproductive cycle. This study focuses on differential expression of the genes involved in the biosynthesis of JH and ecdysone at six time points during the first 30 hr after cell capping in both drone and worker larvae of A. mellifera. This time frame, covering the conclusion of the honey bee brood cell invasion and the start of Varroa''s ovogenesis, is critical to the successful initiation of a reproductive cycle. Our findings support a later activation of the ecdysteroid cascade in honey bee drones compared to worker larvae, which could account for the increased egg production of Varroa in A. mellifera drone cells. The JH pathway was generally downregulated confirming its activity is antagonistic to the ecdysteroid pathway during the larva development. Nevertheless, the genes involved in JH synthesis revealed an increased expression in drones. The upregulation of jhamt gene involved in methyl farnesoate (MF) synthesis came into attention since the MF is not only a precursor of JH but it is also an insect pheromone in its own right as well as JH‐like hormone in Acari. This could indicate a possible kairomone effect of MF for attracting the mites into the drone brood cells, along with its potential involvement in ovogenesis after the cell capping, stimulating Varroa''s initiation of egg laying.     

A new dasycladalean alga from the Lower Cretaceous of the Eastern Carpathians (Romania): Andreiella rajkae nov. gen., nov. sp.

Lower Cretaceous limestones from Bicaz Gorges (Eastern Carpathians, Romania), developed in Urgonian facies, frequently contain dasycladalean algae. In limestone samples collected from the eastern sector of the Bicaz Gorges, we have identified a large dasycladalean alga that we assign here to a new species and genus: Andreiella rajkae nov. gen. nov. sp. The general morphological features and the calcification pattern distinguish this new alga from previously known dasycladaleans with two orders of laterals.     

Optimization of isolation of cellulose from orange peel using sodium hydroxide and chelating agents

Response surface methodology was used to optimize cellulose recovery from orange peel using sodium hydroxide (NaOH) as isolation reagent, and to minimize its ash content using ethylenediaminetetraacetic acid (EDTA) as chelating agent. The independent variables were NaOH charge, EDTA charge and cooking time. Other two constant parameters were cooking temperature (98 °C) and liquid-to-solid ratio (7.5). The dependent variables were cellulose yield and ash content. A second-order polynomial model was used for plotting response surfaces and for determining optimum cooking conditions. The analysis of coefficient values for independent variables in the regression equation showed that NaOH and EDTA charges were major factors influencing the cellulose yield and ash content, respectively. Optimum conditions were defined by: NaOH charge 38.2%, EDTA charge 9.56%, and cooking time 317 min. The predicted cellulose yield was 24.06% and ash content 0.69%. A good agreement between the experimental values and the predicted was observed.     

Short-term impacts of active layer detachments on carbon exchange in a High Arctic ecosystem,Cape Bounty,Nunavut, Canada

Localized permafrost disturbances such as active layer detachments (ALDs) are increasing in frequency and severity across the Canadian Arctic impacting terrestrial ecosystem functioning. However, the contribution of permafrost disturbance-carbon feedbacks to the carbon (C) balance of Arctic ecosystems is poorly understood. Here, we explore the short-term impact of active layer detachments (ALDs) on carbon dioxide (CO₂) exchange in a High Arctic semi-desert ecosystem by comparing midday C exchange between undisturbed areas, moderately disturbed areas (intact islands of vegetation within an ALD), and highly disturbed areas (non-vegetated areas due to ALD). Midday C exchange was measured using a static chamber method between June 23 and August 8 during the 2009 and 2010 growing seasons. Results show that areas of high disturbance had significantly reduced gross ecosystem exchange and ecosystem respiration (R _E) compared to control and moderately disturbed areas. Moderately disturbed areas showed significantly enhanced net ecosystem exchange compared to areas of high disturbance, but were not significantly different from control areas. Disturbance did not significantly impact soil thermal, physical or chemical properties. According to average midday fluxes, ALDs as a whole (moderately disturbed areas: ?1.942 μmol m^?2 s^?1+ highly disturbed areas: 2.969 μmol m^?2 s^?1) were a small CO₂ source of 1.027 μmol m^?2 s^?1 which did not differ significantly from average midday fluxes in control areas 1.219 μmol m^?2 s^?1. The findings of this study provide evidence that the short-term impacts of ALDs on midday, net C exchange and soil properties in a High Arctic semi-desert are minimal.     

Neocomian Microfossil Association from the Taft area near Yazd (central Iran)

Summary An assemblage of microfossils, including calcareous green algae (dasycladaleans:Deloffrella quercifoliipora, Bakalovaella elitzae, Salpingoporella cf.muehlbergii, Terquemella sp.,Neomeris sp., andCylindroporella? sp.; Halimedaceans/Gymnocodiaceans:Boueina sp.Permocalculus aff.minutus), red algae (Solenoporaceans?:Marinella lugeoni), cysts of dinoflagellates? (Cadosina fusca fusca, Colomisphaera aff.conferta) and foraminifers (Torinosuella peneropliformis, Charentia cuvillieri, Commaliama sp.) is described from the carbonate beds within the terrigenous-carbonate Sangestan Formation (Upper Jurassic—Neocomian) exposed near the small village of Zereshk, approximately 63 km SW of Yard, central Iran. The micropaleontological assemblage indicates a late Neocomian (Hauterivian) age of the carbonate beds.     

Amino acid composition of band 3 protein from red blood cells of normal and epileptic children

Amino acid analyses of the band 3 protein purified from erythrocyte membranes of control and epileptic children showed that no major structural abnormalities of this protein could be linked with the red blood cell membrane alterations previously described in child epilepsy and, consequently, the molecular basis of these alterations should be looked for elsewhere.