Chewing the fat; regulating autophagy in Drosophila

Autophagy is the major cellular process responsible for bulk cytoplasmic degradation. Two reports in this issue of Developmental Cell describe how both PI3 kinase and TOR signaling in Drosophila are critical for controlling autophagy in response to developmental and environmental cues.     

Prevalence of non-strongyle gastrointestinal parasites of horses in Riyadh region of Saudi Arabia

This study aimed to provide recent data on the occurrence of non-strongyle intestinal parasite infestation in horses in the Riyadh region of Saudi Arabia as a basis for developing parasite control strategies. We conducted necropsy for 45 horses from September 2006 to November 2007 in the Riyadh region, Saudi Arabia. 39 out of 45 horses were infected with intestinal parasites with an infestation rate of 86.6%. Infestations with seven nematode species and two species of Gasterophilus larva were found. The most prevalent parasites were Strongyloides westeri (64.4%) and Parascaris equorum (28.8%) followed by Habronema muscae (22.2%). Trichostrongylus axei and Oxyuris equi were less common at (11.1%) and (8.8%), respectively. Habronema megastoma and Setaria equine were found in two horses only (4.4%). Gasterophilus intestinalis larvae were recovered from 39 horses (86.6%) and Gasterophilus nasalis larvae were found in 17 horses (37.7%). Season had a significant effect on the prevalence of P. equorum and G. nasalis, while age of horses had a significant effect only on the prevalence of P. equorum. The husbandry in Saudi Arabia appears to be conductive to parasites transmitted in stables or by insects rather than in pasture.     

Fibroblast Growth Factor Receptors (FGFRs) in Human Sperm: Expression,Functionality and Involvement in Motility Regulation

Fibroblast growth factors receptors (FGFRs) have been widely characterized in somatic cells, but there is scarce evidence of their expression and function in mammalian gametes. The objective of the present study was to evaluate the expression of FGFRs in human male germ cells, to determine sperm FGFR activation by the FGF2 ligand and their participation in the regulation of sperm motility. The expression of FGFR1, 2, 3 and 4 mRNAs and proteins in human testis and localization of these receptors in germ cells of the seminiferous epithelium was demonstrated. In ejaculated sperm, FGFRs were localized to the acrosomal region and flagellum. Sperm exposure to FGF2 caused an increase in flagellar FGFR phosphorylation and activation of extracellular signal-regulated kinase (ERK) and protein kinase B (PKB or Akt) signaling pathways. Incubation with FGF2 led to a significant increase in the percentage of total and progressive sperm motility, as well as in sperm kinematics. All responses were prevented by sperm preincubation with BGJ398, a specific inhibitor of FGFR tyrosine kinase activity. In addition to confirming the expression of FGFRs in germ cells of the human testis, our study describes for the first time the presence, localization and functionality of human sperm FGFRs, and provides evidence of the beneficial effect of FGF2 upon sperm motility.     

Attentional demands of movement observation as tested by a dual task approach

Movement observation (MO) has been shown to activate the motor cortex of the observer as indicated by an increase of corticomotor excitability for muscles involved in the observed actions. Moreover, behavioral work has strongly suggested that this process occurs in a near-automatic manner. Here we further tested this proposal by applying transcranial magnetic stimulation (TMS) when subjects observed how an actor lifted objects of different weights as a single or a dual task. The secondary task was either an auditory discrimination task (experiment 1) or a visual discrimination task (experiment 2). In experiment 1, we found that corticomotor excitability reflected the force requirements indicated in the observed movies (i.e. higher responses when the actor had to apply higher forces). Interestingly, this effect was found irrespective of whether MO was performed as a single or a dual task. By contrast, no such systematic modulations of corticomotor excitability were observed in experiment 2 when visual distracters were present. We conclude that interference effects might arise when MO is performed while competing visual stimuli are present. However, when a secondary task is situated in a different modality, neural responses are in line with the notion that the observers motor system responds in a near-automatic manner. This suggests that MO is a task with very low cognitive demands which might be a valuable supplement for rehabilitation training, particularly, in the acute phase after the incident or in patients suffering from attention deficits. However, it is important to keep in mind that visual distracters might interfere with the neural response in M1.     

Studying the drift of in line pH measurements in cell culture

The culture of Chinese hamster ovary (CHO) cells to produce monoclonal antibodies (MAb) requires accurate measurement and control of pH. Unwanted pH drifts in cell culture can adversely affect process performance, product quality, and product yield. To measure and control pH throughout the length of a culture, most cell culture processes use traditional glass pH probes. Several variables can affect the design and performance of glass pH electrodes and lead to drift in the measurement. Understanding these variables and their effects on pH performance can lead to design improvements and potentially reduce the drift. In this study, a set of Rosemount Analytical glass pH probes was investigated in cell culture operations. Electrochemical properties of the probes were monitored throughout the experiments. Experimental results show that the glass membrane potential experiences the biggest change during cell culture operations. Changes in the reference electrode potential are small compared with the changes in glass membrane potential. The glass membranes are affected by the steam sterilization process and this is the main cause for drift in the probe sensing signal during cell culture operations. Steam sterilization can cause the potential of glass membranes to change by up to 15 mV (～ 0.25 pH units). This change in membrane potential can be observed as an undesirable pH drift in bioreactors.     

Testing adaptive hypotheses on the evolution of larval life history in acorn and stalked barnacles

Despite strong selective pressure to optimize larval life history in marine environments, there is a wide diversity with regard to developmental mode, size, and time larvae spend in the plankton. In the present study, we assessed if adaptive hypotheses explain the distribution of the larval life history of thoracican barnacles within a strict phylogenetic framework. We collected environmental and larval trait data for 170 species from the literature, and utilized a complete thoracican synthesis tree to account for phylogenetic nonindependence. In accordance with Thorson's rule, the fraction of species with planktonic‐feeding larvae declined with water depth and increased with water temperature, while the fraction of brooding species exhibited the reverse pattern. Species with planktonic‐nonfeeding larvae were overall rare, following no apparent trend. In agreement with the “size advantage” hypothesis proposed by Strathmann in 1977, egg and larval size were closely correlated. Settlement‐competent cypris larvae were larger in cold water, indicative of advantages for large juveniles when growth is slowed. Planktonic larval duration, on the other hand, was uncorrelated to environmental variables. We conclude that different selective pressures appear to shape the evolution of larval life history in barnacles.