Nouvelles observations sur Goniolina hexagona d’Orbigny Algue Dasycladale du Kimméridgien

During a restudy of the type material of Goniolina hexagona d’Orbigny (Kimmeridgian of Charente-Maritime Department, France), reproductive organs of choristosporate type were discovered. This observation induces us to assign Goniolina to the tribe Bornetelleae L. and J. Morellet.     

Coping with shift work-related circadian disruption: A mixed-methods case study on napping and caffeine use in Australian nurses and midwives

ABSTRACT

Introduction: Two of the most ubiquitous fatigue countermeasures used by shift-working nurses are napping and caffeine. This mixed-methods case study investigated the ways nurses and midwives utilised napping and caffeine countermeasures to cope with shift work, and associated sleep, physical health and psychological health outcomes.

Materials and Methods: N = 130 Australian shift-working nurses and midwives (mean age = 44 years, range = 21–67, 115F, 15M) completed the Standard Shiftwork Index. A sub-set of 22 nurses and midwives completed an in-depth interview.

Results: Nearly 70% of participants reported napping. Those who napped during night shifts had significantly less total sleep time before (F_2,75 = 5.5, p < 0.01) and between days off (F_2,82 = 3.9, p < 0.05). By the end of the night shift, average hours of time awake were significantly less for prophylactic and on-shift nappers compared to non-nappers (F_2,85 = 97.2, p < 0.001). Since starting shift work, the percentage of high caffeine consumers (>400 mg/day) increased from 15% to 33% of the sample and an average of 4 (SD = 2) caffeinated beverages per day was reported. Increased caffeine consumption was associated with greater sleep disturbance (r = 0.26, p < 0.05), psychological distress (r = 0.37, p < 0.001), abdomen pain (r = 0.27, p < 0.05) and weight gain since starting shift work (r = 0.25, p < 0.05). Interviews confirmed these relationships and revealed that caffeine consumption on night shift was common, whereas napping on night shift was dependent on a number of factors including ability to sleep during the day.

Conclusion: This study identified reasons shift workers chose to engage in or abstain from napping and consuming caffeine, and how these strategies related to poor sleep and health outcomes. Further research is required to help develop recommendations for shift workers regarding napping and caffeine consumption as fatigue countermeasures, whilst taking into account the associated hazards of each strategy.     

Flanking Regulatory Sequences of the Tetrahymena R Deletion Element Determine the Boundaries of DNA Rearrangement

In the ciliate Tetrahymena thermophila, thousands of DNA segments of variable size are eliminated from the developing somatic macronucleus by specific DNA rearrangements. It is unclear whether rearrangement of the many different DNA elements occurs via a single mechanism or via multiple rearrangement systems. In this study, we characterized in vivo cis-acting sequences required for the rearrangement of the 1.1-kbp R deletion element. We found that rearrangement requires specific sequences flanking each side of the deletion element. The required sequences on the left side appear to span roughly a 70-bp region that is located at least 30 bp from the rearrangement boundary. When we moved the location of the left cis-acting sequences closer to the eliminated region, we observed a rightward shift of the rearrangement boundary such that the newly formed deletion junction retained its original distance from this flanking region. Likewise, when we moved the flanking region as much as 500 bp away from the deletion element, the rearrangement boundary shifted to remain in relative juxtaposition. Clusters of base substitutions made throughout this critical flanking region did not affect rearrangement efficiency or accuracy, which suggests a complex nature for this regulatory sequence. We also found that the right flanking region effectively replaced the essential sequences identified on the left side, and thus, the two flanking regions contain sequences of analogous function despite the lack of obvious sequence identity. These data taken together indicate that the R-element flanking regions contain sequences that position the rearrangement boundaries from a short distance away. Previously, a 10-bp polypurine tract flanking the M-deletion element was demonstrated to act from a distance to determine its rearrangement boundaries. No apparent sequence similarity exists between the M and R elements. The functional similarity between these different cis-acting sequences of the two elements is firm support for a common mechanism controlling Tetrahymena rearrangement.     

A 140‐kDa glycopeptide from the sperm ligand of the vitelline coat of the freshwater bivalve Unio elongatulus,only contains O‐linked oligosaccharide chains and mediates sperm‐egg interaction

In previous studies we found that sperm binding activity in the vitelline coat of the freshwater bivalve Unio elongatulus is located on the O‐linked oligosaccharide chains of gp273, one of the two major components of the extracellular coat, and that fucose plays a key role in this interaction. In this paper we report the partial characterization of a large glycopeptide (about 140 kDa) obtained by cyanogen bromide fragmentation of gp273, that maintains sperm binding activity. Lectin blotting revealed that the glycopeptide reacted with lectins from Arachis hypogaea (PNA) and Lotus tetragonolobus (LTA) but not Canavalia ensiformis (ConA). No other PNA‐positive fragments could be detected in the electrophoretic pattern of fragmented gp273 but several ConA‐positive fragments of lower molecular weight were present indicating that all the O‐linked chains are clustered together in this fragment. Two‐dimensional gel electrophoresis of the fragment revealed it to be acidic in nature in contrast with the neutral character of the whole gp273 molecule. Competition binding assay showed that this fragment is a strong inhibitor of the interaction, whereas no effect was detected using the ConA‐positive peptides. This confirms that the sperm receptor activity of gp273 is related to its O‐linked chains. The immunodominance of this fragment is also discussed. Mol. Reprod. Dev. 54:203–207, 1999. © 1999 Wiley‐Liss, Inc.     

Microspore embryogenesis induced through in vitro anther culture of almond (<Emphasis Type="Italic">Prunus dulcis</Emphasis> Mill.)

Anther culture is one of the most widely used methods to induce gametic embryogenesis. The aim of this investigation was to induce microspore embryogenesis in almond (Prunus dulcis Mill.), through this technique. Anthers were cultured at the vacuolated developmental stage, and seven cultivars, two culture media and two temperature treatments were assessed. Although evidence of the microspore induction was observed in all the genotypes and treatments tested (symmetrical nucleus division and multinucleated structures), calli were produced merely by anthers cultured in the medium P and the regeneration of embryos was detected only in anthers of the cultivars Filippo Ceo, Lauranne and Genco, placed on medium P and subjected to the Control treatment (direct culture at 25?±?1?°C, without the hot thermal shock at 35?±?1?°C for 7 days). Characterization by SSR marker analysis of the embryo genotypes revealed that the regenerants had a single allele for each locus whereas the parent cultivar was heterozygous, indicating their development from haploid microspores. This study reports the evidence of gametic embryogenesis and, particularly, of microspore embryogenesis through in vitro anther culture, in almond, and, for the first time to our knowledge, the production of homozygous embryos.     

Structure and modeling studies of the carboxy-terminus region of human tropoelastin.

Elastin macromolecular assembly is a highly complex mechanism involving many steps including coacervation, cross-linking, and probably other (not known) phenomena. In past studies, it has been proposed that the C-terminal part of tropoelastin is also involved in this process and may play a key role in tropoelastin interactions with other proteins of the final elastic fibres scaffold. Presented here are the results of the biophysical studies (biospectroscopy, bioinformatics) of the C-terminal domain of tropoelastin. We report the detailed structures adopted by the oxidized (native) and reduced forms of the free synthetic peptide with sequence encoded by exon 36 of human tropoelastin (GGACLGKACGRKRK) and propose a dynamical interpretation of which structures may be involved in interactions with other extra-cellular matrix proteins. We also suggest that these structures may be retrieved in other proteins sharing a consensus sequence; however no definitive conclusion can be drawn here on a possible structure-function relationship.     

Exiting the Golgi complex

The composition and identity of cell organelles are dictated by the flux of lipids and proteins that they receive and lose through cytosolic exchange and membrane trafficking. The trans-Golgi network (TGN) is a major sorting centre for cell lipids and proteins at the crossroads of the endocytic and exocytic pathways; it has a complex dynamic structure composed of a network of tubular membranes that generate pleiomorphic carriers targeted to different destinations. Live-cell imaging combined with three-dimensional tomography has recently provided the temporal and topographical framework that allows the assembly of the numerous molecular machineries so far implicated in sorting and trafficking at the TGN.     

Synthesis, in vitro, and in vivo biological evaluation and molecular docking simulations of chiral alcohol and ether derivatives of the 1,5-diarylpyrrole scaffold as novel anti-inflammatory and analgesic agents

Following our previous research on anti-inflammatory drugs (NSAIDs), we report here the synthesis of chiral 1,5-diarylpyrroles derivatives that were characterized for their in vitro inhibitory effects toward cyclooxygenase (COX) isozymes. Analysis of enzymatic affinity and COX-2 selectivity led us to the selection of one compound (+/-)-10b that was further tested in vitro in the human whole blood (HWB) and in vivo for its anti-inflammatory activity in mice. The affinity data have been rationalized through docking simulations.     

Marine biodiversification in response to evolving phytoplankton stoichiometry

Diversification of the marine biosphere is intimately linked to the evolution of the biogeochemical cycles of carbon, nutrients, and primary productivity. A meta-analysis of the ratio of carbon-to-phosphorus buried in sedimentary rocks during the past 3 billion years indicates that both food quantity and, critically, food quality increased through time as a result of the evolving stoichiometry (nutrient content) of eukaryotic phytoplankton. Evolving food quantity and quality was primarily a function of broad tectonic cycles that influenced not just carbon burial, but also nutrient availability and primary productivity. Increasing nutrient availability during the middle-to-Late Proterozoic culminated in the production of food (phytoplankton biomass and fresh dead organic matter) with C:P Redfield ratios sufficient to finally promote geologically-rapid biodiversification during the Proterozoic–Phanerozoic transition. This resulted in further, massive nutrient sequestration into biomass that triggered positive feedback via nutrient recycling (bioturbation, mesozooplankton grazing) on phytoplankton productivity. Increasing rates and depths of bioturbation through the Phanerozoic suggest that nutrient recycling continued to increase. Increasing bioturbation and nutrient cycling appear to have been necessary to sustain the primary productivity and “energetics” (biomass, metabolic rates, and physical activity such as predation) of the marine biosphere because of the geologically-slow input of macronutrients like phosphorus from land and the continued sequestration of nutrients into marine and terrestrial biomass.     

Update on genotoxicity and carcinogenicity testing of 472 marketed pharmaceuticals

This survey is a compendium of genotoxicity and carcinogenicity information of 838 marketed drugs, whose expected clinical use is continuous for at least 6 months or intermittent over an extended period of time. Of these 838 drugs, 366 (43.7%) do not have retrievable genotoxicity or carcinogenicity data. The remaining 472 (56.3%) have at least one genotoxicity or carcinogenicity test result. Of the 449 drugs with at least one genotoxicity test result, 183 (40.8%) have at least one positive finding. Of the 338 drugs with at least one carcinogenicity test result, 160 (47.3%) have at least one positive result. Concerning the predictivity of genetic toxicology findings for long-term carcinogenesis assays, of the 315 drugs which have both genotoxicity and carcinogenicity data 116 (36.8%) are neither genotoxic nor carcinogenic, 50 (15.9%) are non-carcinogens which test positive in at least one genotoxicity assay, 75 (23.8%) are carcinogenic in at least one sex of mice or rats but test negative in genotoxicity assays, and 74 (23.5%) are both genotoxic and carcinogenic. Only 208 (24.8%) of the 838 drugs considered have all data required by current guidelines for testing of pharmaceuticals. However, it should be noted that a large fraction of the drugs considered were developed and marketed prior to the present regulatory climate. Although the laws do not require re-testing based on revised standards, in the absence of epidemiological studies excluding a carcinogenic risk to humans, a re-evalutation would be appropriate.