Nutritional regulation and kinetics of flocculosin synthesis by Pseudozyma flocculosa

This study sought to identify the factors and conditions that affected production of the antifungal glycolipid flocculosin by the biocontrol agent Pseudozyma flocculosa. For this purpose, different parameters known or reported to influence glycolipid release in fungi were tested. Concentration of the start-up inoculum was found to play an important role in flocculosin production, as the optimal level increased productivity by as much as tenfold. Carbon availability and nitrogen source (i.e., organic vs inorganic) both had a direct influence on the metabolism of P. flocculosa, leading to flocculosin synthesis. In general, if conditions were conducive for production of the glycolipid, carbon availability appeared to be the only limiting factor. On the other hand, if yeast extract was supplied as nitrogen source, fungal biomass was immediately stimulated to the detriment of flocculosin synthesis. Unlike other reports of glycolipid release by yeast-like fungi, inorganic nitrogen starvation did not trigger production of flocculosin. The relationship between the factors influencing flocculosin production in vitro and the conditions affecting the release of the molecule by P. flocculosa in its natural habitat appears to be linked to the availability of a suitable and plentiful food source for the biocontrol agent.     

The adventures of Sonic Hedgehog in development and repair. I. Hedgehog signaling in gastrointestinal development and disease

Hedgehog (Hh) proteins are members of a family of secreted signaling factors that orchestrate the development of many organs and tissues including those of the gastrointestinal (GI) tract. The requirement for Hh activity is not limited to early development but underlies the homeostasis of a number of tissues, and abnormal activity of the Hh pathway is associated with several GI malignancies. Understanding the roles and mechanisms of action of Hh signaling both in development and postnatally should thus give novel insights into potential treatments for these diseases. Here we focus on the Hh signaling pathway and its role in GI tract development and maintenance and consider the diseases resulting from aberrant Hh activity.     

Changes in social environment induce higher emotional disturbances than changes in physical environment in quail

In intensive rearing, birds are exposed to frequent changes in both their social and physical environments, and this can have an impact on animal welfare under commercial conditions. The aim of the present study was to compare the emotional responses induced by social and non-social changes and to study the influence of the familiarity on these responses.Twenty-two female quail were first reared with a ball in 15–20-individual groups for 3 weeks from hatching. Then, each experimental subject was allocated either a familiar congener (CONG) or a familiar object (BALL). At 6 weeks of age the birds were fitted with a telemetric device to collect motor and cardiac activities. After that, each subject was exposed first to a separation from its cage-mate/familiar object, and secondly to the (re-)introduction of either the cage-mate/familiar object or of an unknown conspecific/another ball. Emotional responses were assessed through behavioural reactions and heart rate variability.Before being separated, both BALL and CONG quail showed stereotyped pacing that was more pronounced in BALL quail. BALL quail were not affected by the ball withdrawal, unlike CONG quail which reacted to the separation from their cage-mate by reducing activity and exploratory behaviour (P < 0.05). After the re-introduction, BALL quail remained closer to their ball and CONG quail spent more time with “stretched necks” than before the separation (P < 0.05). Surprisingly, CONG quail showed less stereotyped pacing when their partner was removed and recovered the initial level of stereotyped behaviour when their cage-mate was re-introduced (P < 0.01). Likewise, CONG quail also recovered the initial values of heart rate after the re-introduction of their cage-mate, indicating an increase in sympathetic activity compared to the isolation period. When the unfamiliar congener or ball was introduced in their cage, BALL quail pecked the unknown ball more than the familiar ball and had more contact with it (P < 0.05) and CONG quail had more contact with the unknown congener than with the cage-mate (P < 0.05).In conclusion, the quail appeared to experience a negative affective state before being separated, and there was no clear evidence of negative emotion in quail in response to the separation from either a social partner or an inanimate object. Nevertheless, the emotional responses of the quail in reaction to the (re-)introduction was influenced by the familiarity of the congener or the ball. Finally, changes in the quail's social environment induced more behavioural and cardiac modifications than changes in its non-social environment.     

Peroxisome proliferator-activated receptor gamma activation promotes infiltration of alternatively activated macrophages into adipose tissue

Obesity is associated with infiltration of macrophages into adipose tissue. Adipose macrophages may contribute to an elevated inflammatory status by secreting a variety of proinflammatory mediators, including tumor necrosis factor alpha and interleukin-6 (IL-6). Recent data suggest that during diet-induced obesity the phenotype of adipose-resident macrophages changes from alternatively activated macrophages toward a more classical and pro-inflammatory phenotype. Here, we explore the effect of peroxisome proliferator-activated receptor gamma activation on obesity-induced inflammation in 129SV mice fed a high fat diet for 20 weeks. High fat feeding increased bodyweight gain, adipose tissue mass, and liver triglycerides. Rosiglitazone treatment further increased adipose mass, reduced liver triglycerides, and changed adipose tissue morphology toward smaller adipocytes. Surprisingly, rosiglitazone markedly increased the number of macrophages in adipose tissue, as shown by immunohistochemical analysis and quantification of macrophage marker genes CD68 and F4/80+. In adipose tissue, markers for classically activated macrophages including IL-18 were down-regulated, whereas markers characteristic for alternatively activated macrophages (arginase 1, IL-10) were up-regulated by rosiglitazone. Importantly, conditioned media from rosiglitazone-treated alternatively activated macrophages neutralized the inhibitory effect of macrophages on 3T3-L1 adipocyte differentiation, suggesting that alternatively activated macrophages may be involved in mediating the effects of rosiglitazone on adipose tissue morphology and mass. Our results suggest that short term rosiglitazone treatment increases infiltration of alternatively activated macrophages in adipose tissue. The alternatively activated macrophages might play a role in peroxisome proliferator-activated receptor gamma-dependent expansion and remodeling of adipose tissue.