What Difference Exists in the Pancreas of Mammals With Sanguivorous Diet? a Morphological, Stereological and Immunohistochemical Study of the Pancreatic Islets of the Hematophagous Bat Diphylla Ecaudata.

What difference exists in the pancreas of mammals with sanguivorous diet? A morphological, stereological and immunohistochemical study of the pancreatic islets of the hematophagous bat Diphylla ecaudata.

Regul Pept. 2013 Mar 13;
Machado-Santos C, Aquino JC, Mikalauka JS, Abidu-Figueiredo M, Mendes RM, Sales A

Diphylla ecaudata is a vampire bat that mainly feeds on the blood of birds. This highly specialized diet – hematophagy – is accompanied by a series of morphological changes in the gastro-entero-pancreatic system, since the distribution and relative proportions of different pancreatic endocrine cell types can vary between species due to different physiological conditions and eating habits. The aim of this study was to examine for the first time the pancreas of the vampire bat D. ecaudata using morphological, stereological and immunohistochemical techniques. The pancreas of the D. ecaudata has an exocrine acinar portion in which the highest concentration of pancreatic islets are scattered. These pancreatic islets have irregular size and a mean diameter of 56.94?m. The total number of islets in the pancreas was 23,900, with a volumetric density of 4.1%. Insulin-immunoreactive (IR) cells were located in the central pancreatic islet region and had the largest density (54.8%). Glucagon-IR cells were located mainly in the peripheral mantle region (16.2%), along with somatostatin-IR (SS) cells (14.3%). Cells immunoreactive to insulin, glucagon and somatostatin were also observed spread in isolated places in the exocrine pancreas. In the connective tissue near the pancreatic ducts, a high concentration was identified of insulin-IR cells and a low concentration of glucagon-IR and somatostatin-IR cells. These results indicate that although the pancreas of D. ecaudata has morphological similarities with that of other mammals, it has a differentiated islet structure, because there were a large number of islets and different volumetric densities of ?, ? and ? cells. HubMed – eating


Molecular identification and larval morphological description of Contracaecum pelagicum (Nematoda: Anisakidae) from the anchovy Engraulis anchoita (Engraulidae) and fish-eating birds from the Argentine North Patagonian Sea.

Parasitol Int. 2013 Mar 8;
Garbin LE, Mattiucci S, Paoletti M, Diaz JI, Nascetti G, Navone GT

Anisakids use invertebrates as paratenic and/or intermediate hosts as a basic feature of larval transmission. The third-stage larva usually develops in invertebrates which are prey items of finfish paratenic hosts. Contracaecum larvae moult twice inside the egg and hatch as free third-stage larvae ensheathed in the second-stage larval cuticle. Copepods act as paratenic or obligatory hosts, usually ingesting these free L3 larvae, and fish act as intermediate/paratenic or metaparatenic hosts preying on infected copepods. Fish-eating birds acquire L3 larvae by ingesting infected fish where they develop into the fourth-stage larvae and adults. Objectives of this work were to establish the specific correspondence between C. pelagicum L3 larvae parasitizing the anchovy Engraulis anchoita, and the adults parasitizing the Magellanic penguin Spheniscus magellanicus and the Imperial shag Phalacrocorax atriceps through the use of molecular markers; and, to evaluate the anisakid L3 larval recruitment and infection caused by ingestion of anchovy by S. magellanicus. Sixteen specimens of Contracaecum L3 larvae were analyzed from E. anchoita from Bahía Engaño, Chubut, eight adult nematodes from S. magellanicus and six adult specimens from P. atriceps both from the Valdés Peninsula, Chubut. All nematodes were sequenced for three genes: mitochondrial cytochrome oxidase 2 (mtDNA cox2), mitochondrial ribosomal RNA (rrnS), and the internal transcribed spacers (ITS-1 and ITS-2) of the nuclear ribosomal DNA region. Phylogenetic analyses were performed by using Maximum Parsimony (MP) analysis by PAUP. In addition, studies under SEM and LM were carried out on L3 larvae. All L3 individuals from E. anchoita, adults from S. magellanicus, and P. atriceps clustered in the same clade, well supported in the MP tree inferred from the mtDNA cox2, and rrnS gene sequences analyses. Further, the sequence alignments of L3 larvae and adults of C. pelagicum here obtained at the ITS-1 and ITS-2 regions of the rDNA matched the sequences of C. pelagicum previously deposited by us in GenBank. Nematode recruitment (Ro) was equal to 33.07 (7.20 -91.14) L3 larvae for C. pelagicum in each penguin’s meal of anchovy. The MP tree topologies obtained from mtDNA cox2 and rrnS genes demonstrated that specimens of Contracaecum L3 larvae from E. anchoita and C. pelagicum from S. magellanicus as well as from P. atriceps constitute a unique clade, well-distinct and supported from all the others formed by the Contracaecum spp. sequenced so far for these genes. Molecular markers are considered to be an effective tool to elucidate larval transmission. The Contracaecum L3 larval recruitment value showed that many worms fail to establish in the bird digestive tract, probably because they are below a critical size. Further work is needed to elucidate other factors (e.g., physiological, immunological) that control nematode populations in the penguin digestive tract. HubMed – eating


Endoplasmic reticulum stress induced by 2-deoxyglucose but not glucose starvation activates AMPK through CaMKK? leading to autophagy.

Biochem Pharmacol. 2013 Mar 11;
Xi H, Barredo JC, Merchan JR, Lampidis TJ

Autophagy, a well-conserved cellular self-eating process, has been shown to play a critical role in the pathophysiology of cancer. Previously, we reported that under normal O2 conditions (21% O2), the dual glucose metabolism inhibitor 2-deoxyglucose (2-DG) activates a cytoprotective autophagic response in cancer cells mainly through the induction of endoplasmic reticulum (ER) stress rather than ATP(2) reduction. However, the pathway(s) by which this occurs was unknown. Here, we find that ER stress induced by 2-DG as well as tunicamycin activates AMPK via Ca(2+)-CaMKK? leading to stimulation of autophagy. These results suggest a new role for AMPK as a sensor of ER stress. In contrast, we find that although physiologic glucose starvation (GS) leads to ER stress which contributes to autophagy activation, it does so by a different mechanism. In addition to ER stress, GS also stimulates autophagy through lowering ATP and activating the canonical LKB1-AMPK energy sensing pathway as well as through increasing reactive oxygen species resulting in the activation of ERK. Furthermore, under hypoxia we observe that both 2-DG and GS inhibit rather than activate autophagy. This inhibition correlates with dramatically depleted ATP levels, and occurs through reduction of the PI3K III-Beclin1 complex for autophagy initiation, blockage of the conjugation of ATG12 to ATG5 for autophagosome expansion, as well as inhibition of the functional lysosomal compartment for autophagic degradation. Taken together, our data support a model where under normoxia therapeutic (2-DG) and physiologic (GS) glucose restriction differentially activate autophagy, while under hypoxia they similarly inhibit it. HubMed – eating


Having your cake and eating it too: A habit of comfort food may link chronic social stress exposure and acute stress-induced cortisol hyporesponsiveness.

Physiol Behav. 2013 Mar 14;
Tryon MS, Decant R, Laugero KD

Stress has been tied to changes in eating behavior and food choice. Previous studies in rodents have shown that chronic stress increases palatable food intake which, in turn, increases mesenteric fat and inhibits acute stress-induced hypothalamic-pituitary-adrenal (HPA) axis activity. The effect of chronic stress on eating behavior in humans is less understood, but it may be linked to HPA responsivity. The purpose of this study was to investigate the influence of chronic social stress and acute stress reactivity on food choice and food intake. Forty-one women (BMI=25.9±5.1 kg/m(2), age range=41 to 52 years) were subjected to the Trier Social Stress Task or a control task (nature movie) to examine HPA responses to an acute laboratory stressor and then invited to eat from a buffet containing low- and high- calorie “comfort” snacks. Women were also categorized as high chronic stress or low chronic stress based on Wheaton Social Stress Index scores. Women reporting higher chronic stress and exhibiting low cortisol reactivity to the acute stress task consumed significantly more calories from chocolate cake on both stress and control visits. Chronic stress in the low cortisol reactor group was also positively related to total fat mass, regional fat percentage, and stress-induced negative mood. Further, women reporting high chronic stress consumed significantly less vegetables, but only in those aged 45 years and older. Chronic stress in women within the higher age category was positively related to total calories consumed at the buffet, stress-induced negative mood and food craving. Our results suggest an increased risk for stress eating in persons with a specific chronic stress signature and imply that a habit of comfort food may link chronic social stress and acute stress-induced cortisol hyporesponsiveness. HubMed – eating



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