Biological rhythms in birds — development, insights and perspectives

The aim of this review is to show that probably the internal clock of precocial birds is imprinted in the prenatal period by exogenous factors (zeitgeber). The activity of organ functions occurs early during embryonic development, before this function is ultimately necessary to ensure the survival of the embryo. Prenatal activation of some functional systems may have a training effect on the postnatal efficiency.The development of physiological control systems is influenced by endogenous and exogenous factors during the late prenatal and early postnatal period: epigenetic adaptation processes play an important role in the development of animals; they have acquired characteristics which are innated but not genetically fixed. As a rule, the actual value during the determination period has a very strong influence on the set-point of the system. This will be explained using the example of thermoregulation.It is shown in detail that it seems to be possible to imprint the prenatal development of circadian rhythms by periodic changes of the light-dark cycle but not by rhythmic influence of acoustic signals.Altogether, there are more questions open than solved concerning the perinatal genesis of circadian rhythms in birds. Topics are given for the future research.     

Effect of arm-shoulder fatigue on carpenters at work

The purpose of the study was to analyse the effect of arm-shoulder fatigue on manual performance. Ten experienced carpenters performed three standardized tasks (nailing, sawing and screwing). Electromyographic activity was recorded from six arm-shoulder muscles and the performances were video-filmed. After 45 min of standardized arm-cranking (arm-shoulder-fatiguing exercise of approximately 70%-80% maximal oxygen consumption), the tasks were repeated. The number of work movements and the time taken for each task were recorded and the quality of the work performed was compared. After the fatiguing exercise, only nailing was perceived as being harder and more mistakes were made during nailing and sawing. Movement performance was not influenced during nailing but was slightly slower during sawing and faster during screwing. However, there were increased mean EMG amplitudes in the upper trapezius and biceps muscles during nailing, in the upper trapezius, anterior deltoid and infraspinatus muscles during sawing and in the anterior deltoid muscle during screwing. Of the muscles studied the upper trapezius and anterior deltoid muscles increased their activity most after the arm-shoulder-fatiguing exercise.     

Development of the visual system of anchovy larvae,Engraulis anchoita: A microanatomical description

During the early ontogeny of fish larvae, the accurate development of the visual system plays a key role, because it is involved in locating food, orientation, selection of favorable habitat, and evasion of predators. The structure of the eye of the fish is typical of vertebrates, with some modifications related to the aquatic environment. In the present work, we describe the development of the larval eye of Engraulis anchoita for the first time. Larvae were collected at the Permanent Station of Environmental Studies (EPEA) in coastal waters of the Southwestern Atlantic Ocean during research cruises in 2015 and 2016. We describe the histology of the retina layers, determine the beginning of the functionality of the eye, and discuss a possible synchronization with the development of the digestive tract. This study provides information about the biology of E. anchoita, the most abundant fish species in the southwestern Atlantic Ocean. Also, recent studies have shown responses of the retina and other tissues to the increase in environmental acidity. Therefore, results of this study are also discussed with respect to the possible effect of acidification on the larvae of this species. The continuity of the time series developed at the EPEA will allow monitoring the effect of long-term environmental and biological variables on the early ontogeny of anchovy in the context of climate change. The high commercial fishing potential of E. anchoita due to its high abundance, as well as its essential role in the trophic web of other commercially valuable fishing resources of Argentina, reinforce the need to continue deepening knowledge about this species. Research highlights:

• Eyes of Engraulis anchoita larvae are functional from early larval stages.
• At hatching, the retina is formed by only few layers from which the other layers differentiates during ontogeny.
• Focal distance increases with larval growth.

     

Mate detection success of maleClethrionomys rufocanus in relation to the spatial distribution of sexually receptive females

Summary Mate detection success of male grey-sided voles,Clethrionomys rufocanus, in relation to the spatial distribution of sexually receptive females was studied in an experimental island population. The spatiotemporal distribution of receptive females was controlled by containing females in small, mobile wire-mesh cages, whereas the response by free-ranging males was monitored by means of radiotelemetry. Males were on average more successful in finding oestrous females when females were spatially clumped than when females were spatially overdispersed. In addition, the variance (CV) in male mate detecting success was highest when females had an overdispersed spatial distribution. These results are consistent with predictions from a theoretical model (Ims, 1988b) analysing the effect of mate distribution on male mating success, and with empirical results on prey detection success of predators searching for prey.     

Wood preservation hygiene and environment in the lime-light of actually

Summary Under the ?Bois plus? scheme, the CTBA is currently developing a third party certification, based on the Scrivener law, with the aim of defending the consumers' interests. At this early stage, wood preservatives and treated wood are checked for the efficacy of treatments in order to ensure the stability and security of works in buildings and civil engineering. According to the different classes of risks in service, ?Bois plus? provides the most adeguate level of protection. In the close future, the industry is planning to incorporate, with the help of the CTBA and experts, health criteria within the frame of the ?Bois plus? certification scheme. The means could beSafety indexes, which are objectives of quality for professionals.Safety indexes are concentrations of substances in wood which can be taken as safe for humans and the general environment, while still toxic for the wood pests. This attractive experience aims to make with the brandname ?Bois plus? a synonym of efficacy and safety. This approach meets the essential requirements 1, 3, 4 of the 89/106 EEC directive: mechanical resistance and stability/hygiene, health and environment/safety in use.     

Lysine Succinylation of VBS Contributes to Sclerotia Development and Aflatoxin Biosynthesis in Aspergillus flavus

Aspergillus flavus is a common saprophytic and pathogenic fungus, and its secondary metabolic pathways are one of the most highly characterized owing to its aflatoxin (AF) metabolite affecting global economic crops and human health. Different natural environments can cause significant variations in AF synthesis. Succinylation was recently identified as one of the most critical regulatory post-translational modifications affecting metabolic pathways. It is primarily reported in human cells and bacteria with few studies on fungi. Proteomic quantification of lysine succinylation (Ksuc) exploring its potential involvement in secondary metabolism regulation (including AF production) has not been performed under natural conditions in A. flavus. In this study, a quantification method was performed based on tandem mass tag labeling and antibody-based affinity enrichment of succinylated peptides via high accuracy nano-liquid chromatography with tandem mass spectrometry to explore the succinylation mechanism affecting the pathogenicity of naturally isolated A. flavus strains with varying toxin production. Altogether, 1240 Ksuc sites in 768 proteins were identified with 1103 sites in 685 proteins quantified. Comparing succinylated protein levels between high and low AF-producing A. flavus strains, bioinformatics analysis indicated that most succinylated proteins located in the AF biosynthetic pathway were downregulated, which directly affected AF synthesis. Versicolorin B synthase is a key catalytic enzyme for heterochrome B synthesis during AF synthesis. Site-directed mutagenesis and biochemical studies revealed that versicolorin B synthase succinylation is an important regulatory mechanism affecting sclerotia development and AF biosynthesis in A. flavus. In summary, our quantitative study of the lysine succinylome in high/low AF-producing strains revealed the role of Ksuc in regulating AF biosynthesis. We revealed novel insights into the metabolism of AF biosynthesis using naturally isolated A. flavus strains and identified a rich source of metabolism-related enzymes regulated by succinylation.     

Time of day effect on balance performance,functional capacities and risk of fall in women with rheumatoid arthritis

ABSTRACT

Objective: This study explored the time of day effect of balance performance, functional capacities and risk of fall in three different times in patients with rheumatoid arthritis (RA) and the association between these variations and those of RA symptoms.

Methods: A “discontinual” protocol, composed of three test sessions, carried out at 6 am, 2 pm and 10 pm was set up, in order to investigate the time of day effect of balance performance, functional capacities, risk of fall, stiffness, range of motion, swollen and painful joints in women with RA.

Results: Time Up and Go Test (TUGT), Functional Reach Test (FRT) and tinetti test scores were significantly higher (p < .01) at 6 am and at 10 pm compared to 2 pm. Stiffness, range of motion, swollen and painful joints values were significantly higher (p < .01) at 6 am and at 10 pm compared to 2 pm. A significant difference was observed on the stiffness, range of motion and swollen joints values between 6 am and 10 pm that were higher at 6 am (p < .05).

Using Pearson’s coefficient, correlations were found between RA symptom values; and TUGT, FRT and Tinetti test scores.

Conclusion: Results showed a time of day effect of balance performance, functional capacities and risk of falls in women with RA. This variation indicates an alteration of performance at 6 am and 10 pm. Fluctuations of stiffness, limited range of motion, swollen and painful joints noted are concomitant to those of balance performance, functional capacities, and risk of fall.

Abbreviations: RA: rheumatoid arthritis; H&O questionnaire: Horne and Ostberg questionnaire; PSQI: Pittsburgh sleep quality index; HAQ: health assessment questionnaire; SF-36: the short form-36; WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index; TUGT: Time Up and Go Test; FRT: Functional Reach Test     

Dissipative particle dynamics simulation of a gold nanoparticle system

Dissipative particle dynamics (DPD) was carried out to study systems containing gold atoms, organic ether (oligohydroquinonyl ether terminated with a thiol group) and organic solvents. The components in the simulated system are very different in size and chemical nature. Our simulation showed that the reproduction of the macroscopic experimental phase separation, properly dividing the polymeric molecule into beads, selecting the size of gold bead, and choosing the appropriate interaction parameters between beads are crucial. In addition, the solvent effect was the dominant factor for the formation of spherical aggregates of Au atoms and organic ether molecules. We report the interaction strengths between the solvent and gold clusters. Our work has demonstrated that DPD methods can be applied to the study of complex meso-scale systems.