The microbiome of pest insects:It is not just bacteria

Insects are associated with multiple microbes that have been reported to influence various aspects of their biology. Most studies in insects, including pest species, focus on the bacterial communities of the microbiome even though the microbiome consists of members of many more kingdoms, which can also have large influence on the life history of insects. In this review, we present some key examples of how the different members of the microbiome, such as bacteria, fungi, viruses, archaea, and protozoa, affect the fitness and behavior of pest insects. Moreover, we argue that interactions within and among microbial groups are abundant and of great importance, necessitating the use of a community approach to study microbial-host interactions. We propose that the restricted focus on bacteria very likely hampers our understanding of the functioning and impact of the microbiome on the biology of pest insects. We close our review by highlighting a few open questions that can provide an in-depth understanding of how other components of the microbiome, in addition to bacteria, might influence host performance, thus contributing to pest insect ecology

Expression of GPR17 receptor in a murine model of perinatal brain neuroinflammation and its possible interaction with Wnt pathway

Oligodendrocyte precursor cells (OPCs) are generated in specific germinal regions and progressively maturate to myelinating cells. Oligodendrocytes (OLs) differentiation is regulated by a complex interplay of intrinsic, epigenetic and extrinsic factors, including Wnt and the G protein-coupled receptor referred to as GPR17 (Mitew et al., 2014). This receptor responds to both extracellular nucleotides (UDP, UDP-glucose) and cysteinyl-leukotrienes (Ciana et al., 2006), endogenous signaling molecules involved in inflammatory response and in the repair of brain lesions. GPR17 is highly expressed in OPCs during the transition to immature OLs, but it is down-regulated in mature cells. Accordingly, GPR17-expressing OPCs are already present in mice at birth, increase over time, reach a peak at P10, before the peak of myelination, and then decline in the adult brain (Boda et al., 2011). Of note, in cultured OPCs, early GPR17 silencing has been shown to profoundly affect their ability to generate mature OLs (Fumagalli et al., 2011, 2015). Myelination defects characterize many brain disorders, including perinatal brain injury caused by systemic inflammation (Favrais et al., 2011), which is a leading cause of preterm birth. It has already been suggested that an imbalance in the Wnt/\u3b2-catenin/TCF4 pathway could be involved in the maturation arrest of OLs that is observed in premature infants (Yuen et al., 2014). No data are currently available on GPR17 in perinatal brain injury and on its possible interaction with Wnt pathway. Based on these premises, the aim of this work was to assess if the maturational blockade of OLs due to mild systemic perinatal inflammation, induced by intraperitoneal injections of interleukin-1\u3b2 (IL- 1\u3b2), is accompanied by defects in GPR17 expression and whether the Wnt pathway is involved in the regulation of GPR17. Data showed that in newborn mice exposed to IL-1\u3b2, which induces a blockade of oligodendrocyte maturation, GPR17 expression is not affected at early time point (P5), but it is downregulated at P10, when its expression should be maximal. Moreover, in vitro studies revealed that the maturation blockade of the oligodendroglial cell line Oli-Neu, after treatment with a Wnt Agonist II, is accompanied by a severe inhibition of GPR17 expression. In conclusion, our data have shown that myelination defects observed in perinatal brain injury are associated with defects in GPR17 expression; further studies are needed to characterize the molecular link between Wnt pathway and GPR17 receptor

The influence og growth promotant antibiotics and management system on the presence and prevalence of salmonella in swine

Food contamination due to Salmonella is the cause oflarge numbers of human food-borne illnesses worldwide. Reduction in fecal shedding and prevention of new Salmonella infections in livestock during the late finishing/marketing phase of production are critical control points associated with human food safety. The objectives of this research were to compare the effects of various treatments on the shedding of Salmonella during the late finishing phase of production in littermate swine reared nnder different management conditions. The treatments compared were: 1) multi-site segregated early weaning (SEW) versus continuous flow (CF) rearing of swine, 2) growth promotant antibiotics (medicated) versus no feed antibiotics (unmedicated), 3) 24 hour fasting versus full- feeding

SNX27, a protein involved in down syndrome, regulates GPR17 trafficking and oligodendrocyte differentiation

The G protein-coupled receptor 17 (GPR17) plays crucial roles in myelination. It is highly expressed during transition of oligodendrocyte progenitor cells to immature oligodendrocytes, but, after this stage, it must be down-regulated to allow generation of mature myelinating cells. After endocytosis, GPR17 is sorted into lysosomes for degradation or recycled to the plasma membrane. Balance between degradation and recycling is important for modulation of receptor levels at the cell surface and thus for the silencing/activation of GPR17-signaling pathways that, in turn, affect oligodendrocyte differentiation. The molecular mechanisms at the basis of these processes are still partially unknown and their characterization will allow a better understanding of myelination and provide cues to interpret the consequences of GPR17 dysfunction in diseases. Here, we demonstrate that the endocytic trafficking of GPR17 is mediated by the interaction of a type I PDZ-binding motif located at the C-terminus of the receptor and SNX27, a recently identified protein of the endosome-associated retromer complex and whose functions in oligodendrocytes have never been studied. SNX27 knock-down significantly reduces GPR17 plasma membrane recycling in differentiating oligodendrocytes while accelerating cells' terminal maturation. Interestingly, trisomy-linked down-regulation of SNX27 expression in the brain of Ts65Dn mice, a model of Down syndrome, correlates with a decrease in GPR17+ cells and an increase in mature oligodendrocytes, which, however, fail in reaching full maturation, eventually leading to hypomyelination. Our data demonstrate that SNX27 modulates GPR17 plasma membrane recycling and stability, and that disruption of the SNX27/GPR17 interaction might contribute to pathological oligodendrocyte differentiation defects. GLIA 2016. GLIA 2016;64:1437\u20131460

Structural and functional rejuvenation of the aged brain by an approved anti-asthmatic drug

As human life expectancy has improved rapidly in industrialized societies, age-related cognitive impairment presents an increasing challenge. Targeting histopathological processes that correlate with age-related cognitive declines, such as neuroinflammation, low levels of neurogenesis, disrupted blood-brain barrier and altered neuronal activity, might lead to structural and functional rejuvenation of the aged brain. Here we show that a 6-week treatment of young (4 months) and old (20 months) rats with montelukast, a marketed anti-asthmatic drug antagonizing leukotriene receptors, reduces neuroinflammation, elevates hippocampal neurogenesis and improves learning and memory in old animals. By using gene knockdown and knockout approaches, we demonstrate that the effect is mediated through inhibition of the GPR17 receptor. This work illustrates that inhibition of leukotriene receptor signalling might represent a safe and druggable target to restore cognitive functions in old individuals and paves the way for future clinical translation of leukotriene receptor inhibition for the treatment of dementias

Potential for functional replacement of methanogenic bacteria by acetogenic bacteria in the rumen environment

International audienc

FLOW FIELD IN THE VANED DIFFUSER OF A CENTRIFUGAL PUMP AT DIFFERENT VANE SETTING ANGLES

ABSTRACT Particle image velocimetry (2D-PIV) has been used for the investigation of the time averaged flow field inside the vaned diffuser of a centrifugal pump operating at best efficiency point. Pump performances and the diffuser flow field were analysed for three different vane setting angles. It was evidenced that flow coefficient at the best efficiency point decreases with the diffuser setting angle reduction. From 2D-PIV measurements in five different blade to blade planes, spanwise averaged flow angles and velocity distribution were computed. It was evidenced an influence of the diffuser setting angle on the span-wise distribution of the flow rate and of the absolute mass averaged flow angle at impeller discharge. An overturning, at the diffuser discharge was also evidenced for the two highest setting angles. 2D-PIV flow fields are presented in three different pseudo-secondary planes in order to enlighten the cross flows affecting the diffuser flow field

Low Field in the Vaned Diffuser of a Centrifugal Pump at Different Vane Setting Angles

Particle image velocimetry (2D-PIV) has been used for the investigation of the time and phase-averaged flow field inside the vaned diffuser of a centrifugal pump operating at the best efficiency point (BEP). Pump performances and the diffuser flow field were analyzed for three different vane setting angles. It was evidenced that flow coefficient at the best efficiency point decreases with the diffuser setting angle reduction. From 2D-PIV measurements in five different blade to blade planes, spanwise averaged flow angles and velocity distribution were computed. It was evidenced an influence of the diffuser setting angle on the spanwise distribution of the flow rate and of the absolute mass averaged flow angle at impeller discharge. An overturning at the diffuser discharge was also evidenced for the two highest setting angles. 2D-PIV flow fields are presented in three different pseudosecondary planes in order to enlighten the cross flows affecting the diffuser flow field

Flow field in the vaned diffuser of a centrifugal pump at different vane setting angles

Particle image velocimetry (2D-PIV) has been used for the investigation of the time averaged flow field inside the vaned diffuser of a centrifugal pump operating at best efficiency point. Pump performances and the diffuser flow field were analysed for three different vane setting angles. It was evidenced that flow coefficient at the best efficiency point decreases with the diffuser setting angle reduction. From 2DPIV measurements in five different blade to blade planes, spanwise averaged flow angles and velocity distribution were computed. It was evidenced an influence of the diffuser setting angle on the span-wise distribution of the flow rate and of the absolute mass averaged flow angle at impeller discharge. An overturning, at the diffuser discharge was also evidenced for the two highest setting angles. 2D-PIV flow fields are presented in three different pseudo-secondary planes in order to enlighten the cross flows affecting the diffuser flow field

Influence of the diffuser vane setting angle on the flow field in a radial pump

Particle image velocimetry (2D-PIV) has been used for the investigation of the time averaged flow field inside the vaned diffuser of a centrifugal pump operating at best efficiency point. Pump performances and the diffuser flow field were analysed for three different vane setting angles. It was evidenced that the best efficiency point flow coefficient decreases with the diffuser setting angle reduction. A boundary layer thickness growth on the pressure side, which increases as the flow coefficient decreases, was also shown. No evident separation was ever seen on the diffuser vane suction side even with a sharp diffuser vane LE, used in a previous investigation. The total pressure loss coefficient, obtained from the classical expression proposed by Lieblein for linear cascades, was found to decrease as the setting angle increases. It was evidenced an influence of the diffuser vane setting angle on the impeller slip and an over-turning of the diffuser flow field, at mid-span, with an under-turning at the hub and the shroud, suggesting the occurrence of significant secondary flows