Studies of the fine structure of ovarian interstitial tissue

Summary The post-natal evolution of thecal gland in the domestic fowl has been explored, and a hypothesis for this development is proposed. It is suggested that the surface epithelium of the ovary forms crypts and submicroscopic clefts (ingrowing cords) which contribute with epithelial elements required for the regeneration of some of the ovarian elements, including the thecal glands. Complexes of these ingrowing epithelial cells are forming small islets which, after hormonal stimulation, are transformed into well defined structures, the thecal glands, with a specific function, viz. steroid bio-synthesis.     

Autocatalytic activation of influenza hemagglutinin

Enveloped viruses contain surface proteins that mediate fusion between the viral and target cell membranes following an activating stimulus. Acidic pH induces the influenza virus fusion protein hemagglutinin (HA) via irreversible refolding of a trimeric conformational state leading to exposure of hydrophobic fusion peptides on each trimer subunit. Herein, we show that cells expressing fowl plague virus HA demonstrate discrete switching behavior with respect to the HA conformational change. Partially activated states do not exist at the scale of the cell, activation of HA leads to aggregation of cell surface trimers, and newly synthesized HA refold spontaneously in the presence of previously activated HA. These observations imply a feedback mechanism involving self-catalyzed refolding of HA and thus suggest a mechanism similar to the autocatalytic refolding and aggregation of prions.     

Development of the mitochondrial apparatus and blood supply of skeletal muscle fibers during ontogenesis of domestic fowl

The diameter, length, and numerical density of capillaries, diameter of muscle fibers, size and numerical density of mitochondrial profiles, and relative volume of mitochondria in them were determined in the chicken red oxidative gastrocnemius and white glycolytic pectoral muscle during development from day 10 of embryogenesis to six month of postnatal life. The bulk blood flow was measured in these muscles by hydrogen clearance during postembryonic development. During embryogenesis, the fibers of gastrocnemius muscle develop and grow at a higher rate, while during postembryonic development, those of the pectoral muscle develop faster. The density of mitochondrial profiles increases during embryogenesis and decreases after hatching, while their mean size increases, especially in the oxidative fibers, but it somewhat decreases in 6-month old chicks. Redistribution of mitochondria across the fiber section during development takes place in both muscles: they are localized predominantly in the center in 18-day embryos and in the periphery, especially in the gastrocnemius fibers, in 6-month old chicks. At hatching, the length of capillaries is similar in both muscles, but as chicks grow, the proportion of longer (more than 600 µm) capillaries in the pectoral muscle sharply increases, while their density and bulk blood flow decrease. Ratios were determined between structural parameters of the capillary bed and mitochondria, on the one hand, and oxygen consumption (ml/min per 1 mm fiber and 100 g muscle mass), on the other.__________Translated from Ontogenez, Vol. 36, No. 2, 2005, pp. 135–144.Original Russian Text Copyright © 2005 by Belichenko, Korostyshevskaya, Maksimov, Shoshenko.     

乌骨鸡胚胎发育过程中卵内蛋白质脂肪的变化研究

对乌骨鸡胚胎发育过程中卵内各组成成分(蛋清、蛋黄、胚胎)在不同胚龄(即入孵的第0、3、6、9、12、15、18d和出壳)时蛋白质、脂肪含量变化进行测定与分析．结果表明：在不同胚龄时,蛋清中蛋白质含量显著高于蛋黄,蛋黄中脂肪含量始终高于蛋清;而胚胎中的蛋白质、脂肪逐渐增加。另外,胚胎发育过程中胚胎蛋白质的主要来源是蛋黄中的蛋白质,说明蛋黄是禽类胚胎发育过程中营养需要的主要来源。     

A guinea fowl genome assembly provides new evidence on evolution following domestication and selection in galliformes

The helmeted guinea fowl Numida meleagris belongs to the order Galliformes. Its natural range includes a large part of sub‐Saharan Africa, from Senegal to Eritrea and from Chad to South Africa. Archaeozoological and artistic evidence suggest domestication of this species may have occurred about 2,000 years BP in Mali and Sudan primarily as a food resource, although villagers also benefit from its capacity to give loud alarm calls in case of danger, of its ability to consume parasites such as ticks and to hunt snakes, thus suggesting its domestication may have resulted from a commensal association process. Today, it is still farmed in Africa, mainly as a traditional village poultry, and is also bred more intensively in other countries, mainly France and Italy. The lack of available molecular genetic markers has limited the genetic studies conducted to date on guinea fowl. We present here a first‐generation whole‐genome sequence draft assembly used as a reference for a study by a Pool‐seq approach of wild and domestic populations from Europe and Africa. We show that the domestic populations share a higher genetic similarity between each other than they do to wild populations living in the same geographical area. Several genomic regions showing selection signatures putatively related to domestication or importation to Europe were detected, containing candidate genes, most notably EDNRB2, possibly explaining losses in plumage coloration phenotypes in domesticated populations.     

System-specific distribution of zinc in the chick brain

Summary The brain of young domestic chicks was investigated using a Timm sulfide silver method. Serial Vibratome sections were analyzed under the light microscope, and the localization of zinc-positive structures in selected areas was determined at the ultrastructural level. Both strong and differential staining was visible in the avian telencephalon whereas most subtelencephalic structures showed a pale reaction. The highest staining intensity was found in the nonprimary sensory regions of the telencephalon such as the hyperstriatum dorsale, hyperstriatum ventrale, hippocampus, palaeostriatum augmentatum, lobus parolfactorius and caudal parts of neostriatum. There was an overall gradient of staining intensity in neostriatal areas from rostral to caudal with the heaviest zinc deposits in the caudal neostriatum. Primary sensory projection areas, such as the ectostriatum (visual), hyperstriatum intercalatum superius (visual), nucleus basalis (beak representation), the input layer L₂ of the auditory field L and the somatosensory area rostral to field L were selectively left unstained. Fiber tracts throughout the brain were free of zinc deposits except for glial cells. In electron micrographs of stained regions, silver grains were localized in some presynaptic boutons of asymmetric synapses (Gray type I), within the cytoplasm of neuronal somata and sporadically in the nucleus. The possible involvement of zinc in synaptic transmission and other processes is discussed.Abbreviations for Anatomical Structures used in the Text and Figures Ac Nucleus accumbens - Ad Archistriatum dorsale - Ai Archistriatum intermedium - Am Archistriatum mediale - Ap Archistriatum posterior - APH Area parahippocampalis - BAS Nucleus basalis - BO Bulbus olfactorius - Cb Cerebellum; - CbI Nucleus cerebellaris internus - CbM Nucleus cerebellaris intermedius - CDL Area corticoidea dorsolateralis - CPi Cortex piriformis - CT Commissura tectalis - DMP Nucleus dorsomedialis posterior thalami - E Ectostriatum - H Hyperstriatum - HA Hyperstriatum accessorium - HD Hyperstriatum dorsale - HIS Hyperstriatum intercalatum superius - Hp Hippocampus - HV Hyperstriatum ventrale - ICo Nucleus intercollicularis - Ipc Nucleus isthmi, pars parvocellularis - L Lingula - L _{1, 2, 3} Field L - La Nucleus laminaris - LFM Lamina frontalis suprema - LFS Lamina frontalis superior - LH Lamina hyperstriatica - LMD Lamina medullaris dorsalis - LNH Rostrolateral neostriatum/Hyperstriatum ventrale - LPO Lobus parolfactorius - M Medulla - MLd Nucleus mesencephalicus lateralis, pars dorsalis - MNH Rostromedial neostriatum/Hyperstriatum ventrale - N Neostriatum - NC Neostriatum caudale - NEB Nucleus of ectostriatal belt - NHA Nucleus of HA - PA Palaeostriatum augmentatum - Pap Nucleus papillioformis - PL Nucleus pontis lateralis - PP Palaeostriatum primitivum - RP Nucleus reticularis pontis caudalis - Rt Nucleus rotundus - S Nucleus septalis - SS Somatosensory area - TeO Tectum opticum - Tn Nucleus taeniae - TPO Area temporoparieto-occipitalis - V Ventricle - Va Vallecula     

Motile cells in the mucosa of the cloacal urodaeum and proctodaeum of the hen

Summary Motile cells (mast cells, granulocytes, lymphoid cells) are described in the mucosa of the cloacal urodaeum and proctodaeum of the female domestic fowl. Diffuse lymphoid tissue with lymphatic nodules occurs in the urodaeum at the ureteral ostium. Small local aggregations of lymphoid tissue can be observed in the mucosa of the proctodaeum. Cells originating from these sites penetrate the basal lamina of the epithelium and are then found between the epithelial cells.In the subepithelial layers the motile cells sometimes are in contact with each other. Mast cells (tissue basophils) form contact zones, resembling desmosomes or half desmosomes, with smooth muscle cells. In the mast cells three types of granules can be distinguished. Their ultrastructure is discussed in comparison with that in similar cells of the guinea pig.Dedicated to Professor Dr. med. M. Watzka in honor of his 75th birthday     

Housing and dustbathing effects on northern fowl mites (Ornithonyssus sylviarum) and chicken body lice (Menacanthus stramineus) on hens

Hen housing (cage or cage-free) did not impact overall abundances of northern fowl mites, Ornithonyssus sylviarum (Canestrini & Fanzago) (Acari: Macronyssidae), or chicken body lice, Menacanthus stramineus (Nitzsch) (Phthiraptera: Menoponidae). Cage-free hens received a dustbox with sand plus diatomaceous earth (DE), kaolin clay or sulphur. Weekly use varied from none to 100% of hens; 73% of hens used the dustbox at least once. Ectoparasite populations on dustbathing hens (users) were compared with those on non-user cage-free and caged hens. All materials reduced ectoparasites on user hens by 80-100% after 1 week of dustbox use. Diatomaceous earth and kaolin failed to reduce ectoparasites on non-user hens, and ectoparasites on user hens recovered after dustbox removal. A sulphur dustbox eliminated mites from all hens (including non-users) within 2-4 weeks. Residual sulphur controlled mites until the end of the experiment (up to 9 weeks), even after the dustbox was removed. Louse populations on hens using the sulphur dustbox were reduced in 1-2 weeks. Residual sulphur effects were less evident in lice, but the use of a sulphur dustbox by a higher proportion of hens extended louse control to all hens. This is the first experimental study to show that bird dustbathing in naturally and widely available dust materials (particularly kaolin) can suppress ectoparasites and thus the behaviour is probably adaptive.