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RFamide peptides have been localized to a number of neuronsof the CNS of the leech, Hirudo medicinalis, using immunocytochemicaltechniques. The majority of this immunoreactivity appears tobe due to the peptide FMRFamide. Most of the identified RFamideimmunoreactive cells are cholinergic motor neurons, though someare interneurons. Superfused FMRFamide is active on the targetsof these identified neurons; in a few well studied cases, ithas been possible to show that FMRFamide mimics a specific physiologicalaction of an identified neuron on its target. In the leech as in other phyla where they occur, RFamide peptidesare widely distributed in neurons, and are neuromodulators withdiverse physiological effects. 相似文献
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Twenty-one pull-through procedures for congenital aganglionic megacolon (Hirschsprung's disease) have been performed at the Los Angeles Children's Hospital since the adoption of the etiological concept of a distal aganglionic segment in 1949. In 14 cases the Swenson procedure as modified by Hiatt was employed, with perineal excision of the colon segment. There were four postoperative deaths and three symptomatic recurrences in this group. Three patients were treated by transabdominal resection of colon and rectum with subsequent pull-through reconstruction (Swenson). Anterior resection (State) was carried out in two cases. Three children with recurrence of symptoms following primary operation were subjected to a secondary pull-through procedure with an eventual successful outcome. The major portion of the postoperative mortality (29 per cent) in this group occurred in infants less than six months of age in whom anastomotic disruption or proximal segment infarction occurred after operation.A study of 31 cases of congenital aganglionic megacolon in very young infants drew attention to the difficulty of establishing a diagnosis in this age group even at exploratory laparotomy. Among these infants the mortality rate was excessive, regardless of the form of therapy employed. Colostomy appeared to be the indicated surgical procedure if a conservative regimen failed to control intractable colonic obstruction during the first year of life. 相似文献
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Understanding the mechanisms that influence variation in sexually selected ornaments in seabirds has been challenging owing to the difficulty of capturing and sampling individuals outside of the breeding period when ornaments are usually grown. Stable carbon (δ13 C) and nitrogen (δ15 N) isotopes were used to examine the influence of pre-breeding diet composition on ornament size in the Rhinoceros Auklet Cerorhinca monocerata , a socially monogamous seabird that breeds in the North Pacific. We analysed stable isotopes in adult feathers grown during the pre-alternate moult, which allowed us to infer diet composition during the pre-breeding (February–March) period. Females that fed more on inshore fish had larger horns than females that fed more on euphausiids (also known as krill; Euphausiacea). Body size was a stronger predictor of horn height in males than females, suggesting that ornaments may serve as different signals for each sex. This study provides evidence that diet during the pre-breeding period can influence ornament size and emphasizes the importance of understanding individual ecology throughout the annual cycle for determining the factors that influence mate choice and fitness. 相似文献
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M.M. Martorell M. Lannert C.V. Matula M.L. Quartino L.I.C. de Figueroa WP Mac Cormack L.A.M. Ruberto 《Fungal biology》2021,125(3):218-230
In marine ecosystems, macroalgae are the habitat for several microorganisms, fungi being among them. In the Antarctic benthic coastal ecosystem, macroalgae play a key role in organic matter cycling. In this study, 13 different macroalgae from Potter Cove and surrounding areas were sampled and 48 fungal isolates were obtained from six species, four Rhodophyta Ballia callitricha, Gigartina skottsbergii, Neuroglossum delesseriae and Palmaria decipiens, and two Phaeophyceae: Adenocystis utricularis and Ascoseira mirabilis. Fungal isolates mostly belonged to the Ascomycota phylum (Antarctomyces, Cadophora, Cladosporium, Penicillium, Phialocephala, and Pseudogymnoascus) and only one to the phylum Mucoromycota. Two of the isolates could not be identified to genus level, implying that Antarctica is a source of probable novel fungal taxa with enormous bioprospecting and biotechnological potential. 73% of the fungal isolates were moderate eurypsychrophilic (they grew at 5–25 °C), 12.5% were eurypsychrophilic and grew in the whole range, 12.5% of the isolates were narrow eurypsychrophilic (growth at 15–25 °C), and Mucoromycota AUe4 was classified as stenopsychrophilic as it grew at 5–15 °C. Organic extracts of seven macroalgae from which no fungal growth was obtained (three red algae Georgiella confluens, Gymnogongrus turquetii, Plocamium cartlagineum, and four brown algae Desmarestia anceps, D. Antarctica, Desmarestia menziesii, Himantothallus grandifolius) were tested against representative fungi of the genera isolated in this work. All extracts presented fungal inhibition, those from Plocamium cartilagineum and G. turquetii showed the best results, and for most of these macroalgae, this represents the first report of antifungal activity and constitute a promising source of compounds for future evaluation. 相似文献
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