Effect of intraperitoneal CCK-8 on food intake and brain orexin-A after 48 h of fasting in the rat

We investigated the interactions of the peripheral satiety peptide cholecystokinin and the brain orexin-A system in the control of food intake. The effect of an intraperitoneal (i.p.) injection of sulfated cholecystokinin octapeptide (in this article called CCK) (5 microg/kg, 4.4 nmol/kg) or of phosphate-buffered saline (PBS, vehicle control) on 48 h fasting-induced feeding and on orexin-A peptide content was analyzed in diverse brain regions innervated by orexin neurons and involved in the control of food intake. Administration of CCK after a 48 h fast reduced fasting-induced hyperphagia (P<0.05). I.p. CCK increased the orexin-A content in the posterior brainstem of 48 h fasted rats by 35% (P<0.05). Fed animals receiving CCK had 48% higher orexin-A levels in the posterior brainstem than fasted rats (P<0.05). In the lateral hypothalamus, fasting decreased orexin-A levels by 50% as compared to fed rats (P<0.05). In the septal nuclei, the combination of fasting and CCK administration reduced orexin-A contents compared to fed PBS and CCK animals by 13% and 17%, respectively (P<0.05). These results suggest a convergence of pathways activated by peripheral CCK and by fasting on the level of orexin-A released in the posterior brainstem and provide evidence for a novel interaction between peripheral satiety signaling and a brain orexigen in the control of food intake.     

Role for glutathione in the hyposensitivity of LPS-pretreated mice to LPS anorexia

To study the role of the redox state regulator glutathione (GSH) in bacterial lipopolysaccharide (LPS)-induced anorexia we measured total reduced GSH (trGSH) in liver, serum and brain in response to intraperitoneal (ip) lipopolysaccharide (LPS, 4 microg/mouse) injection in LPS-na?ve and LPS-pretreated (4 microg/mouse given 3 days earlier) mice. LPS reduced food intake in LPS-na?ve mice and LPS pretreatment attenuated this effect. LPS decreased trGSH at 24 hours after injection in LPS-na?ve mice but 4 days later trGSH levels were upregulated in brain and liver, and this was associated with a significant attenuation of LPS-induced anorexia. In addition, LPS increased mitochondrial GSH levels in brain and liver at 4 days after injection. Pharmacological GSH depletion with diethylmaleate and L-buthionine sulfoximine in LPS-pretreated mice ablated the hyposensitivity to the anorexic effect of LPS. Together, these findings suggest a prominent role for GSH and its intracellular repartition in LPS anorexia.     

Golgi regeneration after brefeldin A treatment in BY-2 cells entails stack enlargement and cisternal growth followed by division

Brefeldin A (BFA) treatment stops secretion and leads to the resorption of much of the Golgi apparatus into the endoplasmic reticulum. This effect is reversible upon washing out the drug, providing a situation for studying Golgi biogenesis. In this investigation Golgi regeneration in synchronized tobacco BY-2 cells was followed by electron microscopy and by the immunofluorescence detection of ARF1, which localizes to the rims of Golgi cisternae and serves as an indicator of COPI vesiculation. Beginning as clusters of vesicles that are COPI positive, mini-Golgi stacks first become recognizable 60 min after BFA washout. They continue to increase in terms of numbers and length of cisternae for a further 90 min before overshooting the size of control Golgi stacks. As a result, increasing numbers of dividing Golgi stacks were observed 120 min after BFA washout. BFA-regeneration experiments performed on cells treated with BFA (10 microg mL(-1)) for only short periods (30-45 min) showed that the formation of ER-Golgi hybrid structures, once initiated by BFA treatment, is an irreversible process, the further incorporation of Golgi membranes into the ER continuing during a subsequent drug washout. Application of the protein kinase A inhibitor H-89, which effectively blocks the reassembly of the Golgi apparatus in mammalian cells, also prevented stack regeneration in BY-2 cells, but only at very high, almost toxic concentrations (>200 microm). Our data suggest that under normal conditions mitosis-related Golgi stack duplication may likely occur via cisternal growth followed by fission.     

Hes1 Increases the Invasion Ability of Colorectal Cancer Cells via the STAT3-MMP14 Pathway

The Notch pathway contributes to self-renewal of tumor-initiating cell and inhibition of normal colonic epithelial cell differentiation. Deregulated expression of Notch1 and Jagged1 is observed in colorectal cancer. Hairy/enhancer of split (HES) family, the most characterized targets of Notch, involved in the development of many cancers. In this study, we explored the role of Hes1 in the tumorigenesis of colorectal cancer. Knocking down Hes1 induced CRC cell senescence and decreased the invasion ability, whereas over-expression of Hes1 increased STAT3 phosphorylation activity and up-regulated MMP14 protein level. We further explored the expression of Hes1 in human colorectal cancer and found high Hes1 mRNA expression is associated with poor prognosis in CRC patients. These findings suggest that Hes1 regulates the invasion ability through the STAT3-MMP14 pathway in CRC cells and high Hes1 expression is a predictor of poor prognosis of CRC.     

Community Assembly of Biological Soil Crusts of Different Successional Stages in a Temperate Sand Ecosystem, as Assessed by Direct Determination and Enrichment Techniques

In temperate regions, biological soil crusts (BSCs: complex communities of cyanobacteria, eukaryotic algae, bryophytes, and lichens) are not well investigated regarding community structure and diversity. Furthermore, studies on succession are rare. For that reason, the community assembly of crusts representing two successional stages (initial, 5 years old; and stable, >20 years old) were analyzed in an inland sand ecosystem in Germany in a plot-based approach (2 × 18 plots, each 20 × 20 cm). Two different methods were used to record the cyanobacteria and eukaryotic algae in these communities comprehensively: determination directly out of the soil and enrichment culture techniques. Additionally, lichens, bryophytes, and phanerogams were determined. We examine four hypotheses: (1) A combination of direct determination and enrichment culture technique is necessary to detect cyanobacteria and eukaryotic algae comprehensively. In total, 45 species of cyanobacteria and eukaryotic algae were detected in the study area with both techniques, including 26 eukaryotic algae and 19 cyanobacteria species. With both determination techniques, 22 identical taxa were detected (11 eukaryotic algae and 11 cyanobacteria). Thirteen taxa were only found by direct determination, and ten taxa were only found in enrichment cultures. Hence, the hypothesis is supported. Additionally, five lichen species (three genera), five bryophyte species (five genera), and 24 vascular plant species occurred. (2) There is a clear difference between the floristic structure of initial and stable crusts. The different successional stages are clearly separated by detrended correspondence analysis, showing a distinct structure of the community assembly in each stage. In the initial crusts, Klebsormidium flaccidum, Klebsormidium cf. klebsii, and Stichococcus bacillaris were important indicator species, whereas the stable crusts are especially characterized by Tortella inclinata. (3) The biodiversity of BSC taxa and vascular plant species increases from initial to stable BSCs. There are significantly higher genera and species numbers of cyanobacteria and eukaryotic algae in initial BSCs. Stable BSCs are characterized by significantly higher species numbers of bryophytes and vascular plant species. The results show that, in the investigated temperate region, the often-assumed increase of biodiversity in the course of succession is clearly taxa-dependent. Both successional stages of BSCs are diversity “hot spots” with about 29 species of all taxa per 20 × 20 cm plot. (4) Nitrogen and chlorophyll a concentrations increase in the course of succession. The chlorophyll a content of the crusts (cyanobacteria, eukaryotic algae, bryophyte protonemata) is highly variable across the studied samples, with no significant differences between initial and stable BSCs; nor were ecologically significant differences in soil nutrient contents observed. According to our results, we cannot confirm this hypothesis; the age difference between our two stages is probably not big enough to show such an increase. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Biological soil crusts and their microenvironment: Impact on emergence,survival and establishment of seedlings

To elucidate the impact of biological soil crusts (BSCs) on the establishment of habitat-typical vascular plant species, we studied the effects of seed location (surface versus sub-surface), age of crusts (initial versus stable), long rainy periods (continuous versus discontinuous watering) and microenvironment (cracks versus no cracks). In addition, we investigated growth height, phytomass and N-content of one vascular plant species (Phleum arenarium). Initial crusts were compared with older, stable crusts using seven habitat-typical plant species representing different life forms (annuals versus perennials). Our model ecosystem, situated in the temperate zone (but edaphically dry), is characterised by calcareous sand with threatened pioneer vegetation (Koelerion glaucae). We carefully translocated soil monoliths of these crusts and analysed the effects under common garden conditions.     

Regulation of adipocyte formation by GLP-1/GLP-1R signaling

Increased nutrient intake leads to excessive adipose tissue accumulation, obesity, and the development of associated metabolic disorders. How the intestine signals to adipose tissue to adapt to increased nutrient intake, however, is still not completely understood. We show here, that the gut peptide GLP-1 or its long-lasting analog liraglutide, function as intestinally derived signals to induce adipocyte formation, both in vitro and in vivo. GLP-1 and liraglutide activate the GLP-1R, thereby promoting pre-adipocyte proliferation and inhibition of apoptosis. This is achieved at least partly through activation of ERK, PKC, and AKT signaling pathways. In contrast, loss of GLP-1R expression causes reduction in adipogenesis, through induction of apoptosis in pre-adipocytes, by inhibition of the above mentioned pathways. Because GLP-1 and liraglutide are used for the treatment of type 2 diabetes, these findings implicate GLP-1 as a regulator of adipogenesis, which could be an alternate pathway leading to improved lipid homeostasis and controlled downstream insulin signaling.     

Contractile behavior of the forelimb digital flexors during steady-state locomotion in horses (Equus caballus): an initial test of muscle architectural hypotheses about in vivo function

The forelimb digital flexors of the horse display remarkable diversity in muscle architecture despite each muscle-tendon unit having a similar mechanical advantage across the fetlock joint. We focus on two distinct muscles of the digital flexor system: short compartment deep digital flexor (DDF(sc)) and the superficial digital flexor (SDF). The objectives were to investigate force-length behavior and work performance of these two muscles in vivo during locomotion, and to determine how muscle architecture contributes to in vivo function in this system. We directly recorded muscle force (via tendon strain gauges) and muscle fascicle length (via sonomicrometry crystals) as horses walked (1.7 m s(-1)), trotted (4.1 m s(-1)) and cantered (7.0 m s(-1)) on a motorized treadmill. Over the range of gaits and speeds, DDF(sc) fascicles shortened while producing relatively low force, generating modest positive net work. In contrast, SDF fascicles initially shortened, then lengthened while producing high force, resulting in substantial negative net work. These findings suggest the long fibered, unipennate DDF(sc) supplements mechanical work during running, whereas the short fibered, multipennate SDF is specialized for economical high force and enhanced elastic energy storage. Apparent in vivo functions match well with the distinct architectural features of each muscle.