On the optimal growth of the alimentary tract in avian postembryonic development

It was shown in the mathematical model described elsewhere that when growth rate of the chicks is maximized and not constrained by the food availability, the optimal relationship between body mass and alimentary tract mass should conform to a single straight line, or two-, or three-segmented straight lines. Here, we present the data on growth of 11 bird species, and we test the model using the mass of intestines as an indicator of growth of the alimentary tract. The results support the predictions of the model for altricial species and contradict them for precocials. Since precocial species examined here were not food-limited, we suggest that the lack of optimal growth of their alimentary tract is inherent to their mode of development. This may account for their lower growth rate, as compared to altricials. The existence of the optimal growth of the alimentary tract in altricial nestlings suggests that under natural conditions the food is much more abundant than it is generally assumed.     

Immunohistochemical demonstration of carbonic anhydrase isoenzyme VI (CA VI) expression in rat lower airways and lung.

Carbonic anhydrase isoenzyme VI (CA VI), which is transported in high concentrations in saliva and milk into the alimentary tract, is an important element of mucosal protection in the upper alimentary tract. Like alimentary tract mucosa, the respiratory tract mucosa is also exposed to heavy microbial, physical, and chemical stress. The protective and renewal-promoting factors present in the surface mucus of the respiratory tract are mainly produced by the seromucous tracheobronchial glands. Here we studied the secretion of CA VI by these glands in adult and developing rats using immunohistochemical techniques. The serous acinar and duct cells of the tracheobronchial glands stained for CA VI. The presence of the enzyme also in the duct content indicates its active secretion into the surface mucus. CA VI was also visible in the secretory cells and at the base of the ciliated cells of the tracheobronchial surface epithelium. Moreover, the Clara cells of the bronchiolar surface epithelium stained for CA VI. These findings are consistent with the hypothesis that CA VI has a mucosa-protective role not only in the gastrointestinal tract but also in the respiratory tract, where CA VI may act as a pivotal pH neutralizer and growth factor.     

Identification and characterization of functional aquaporin water channel protein from alimentary tract of whitefly, Bemisia tabaci

Some hemipteran xylem and phloem-feeding insects have evolved specialized alimentary structures or filter chambers that rapidly transport water for excretion or osmoregulation. In the whitefly, Bemisia tabaci, mass movement of water through opposing alimentary tract tissues within the filter chamber is likely facilitated by an aquaporin protein. B. tabaci aquaporin-1 (BtAQP1) possesses characteristic aquaporin topology and conserved pore-forming residues found in water-specific aquaporins. As predicted for an integral transmembrane protein, recombinant BtAQP1 expressed in cultured insect cells localized within the plasma membrane. BtAQP1 is primarily expressed in early instar nymphs and adults, where in adults it is localized in the filter chamber and hindgut. Xenopus oocytes expressing BtAQP1 were water permeable and mercury-sensitive, both characteristics of classical water-specific aquaporins. These data support the hypothesis that BtAQP1 is a water transport protein within the specialized filter chamber of the alimentary tract and functions to translocate water across tissues for maintenance of osmotic pressure and/or excretion of excess dietary fluid.     

美国白蛾幼虫消化道形态和超微结构观察

美国白蛾Hyphantria cunea Drury是我国重要的林业检疫性害虫之一,世界范围内寄主多达600余种,对我国林业生产和生态环境建设造成了巨大损失。明确美国白蛾幼虫消化道各部分的形态结构,可为进一步研究其幼虫的食性及消化机能奠定基础。利用光学显微镜、扫描电子显微镜与透射电子显微镜观察了美国白蛾6龄幼虫消化道形态及超微结构。美国白蛾幼虫的消化道由前肠、中肠、后肠组成。前肠是消化道最长的部分,占整个消化道的54.27%,包括咽、食道、嗉囊、前胃四部分;中肠较短,占整个消化道的21.28%,内部具围食膜;后肠由幽门、回肠、结肠和直肠组成,幽门由幽门锥和幽门瓣组成。马氏管共6条,丝腺2条。美国白蛾幼虫消化道总体结构大部分鳞翅目消化道结构相似,但是其前肠在长度上发生了较大的变异,本文进一步讨论了美国白蛾幼虫消化道结构与其食性及耐饥饿能力等的相关性。     

Why cattle feed much and humans think much - New approach to confirm the expensive tissue hypothesis by molecular data

The “expensive tissue hypothesis” states that large brains are active at high metabolic rates, which have to be financed by a significant trade-off with other organs such as the alimentary tract. Recent morphological findings on primate brains and guts support this idea also considering the importance of high-energy diets as a possible driving power of this process. However, the trade-off correlation between brain and alimentary tract, the essence of the “expensive tissue hypothesis”, has not yet been tested using molecular data to complement morpho-functional findings. We therefore hypothesize that the activity of marker proteins expressed both in brain and alimentary tract should parallel functional morphology in organs at the molecular level. Thus, in animals feeding on hard to digest diet, we would expect a high concentration per unit mass of that marker protein in the digestive tract and reversely a lower concentration in the brain. In contrast, in animals feeding on easily-digested, high-energy food we would expect the reverse pattern. Recent preliminary studies suggest that carbonic anhydrase II (CA-II) could act as a marker. The enzyme concentration was found to increase in the brain with higher cerebral activity from cattle to humans and to reversely decrease in salivary secretions. The reverse concentration of CA-II in saliva and brains of cattle and primates might be the first molecular evidence of the validity of the “expensive tissue hypothesis”.     

Cuterebra buccata: immune response in myiasis of domestic rabbits

Naturally infected rabbits (Oryctolagus) were used to define further the nature of the immune response in myiasis due to Cuterebra buccata. Third instar larvae were dissected into four fractions; (1) alimentary tract with attached organs, (2) hemolymph, (3) fat body with tracheae, and (4) cuticle with attached muscles. The antigens provoking immune phenomena in naturally infected rabbits were found to reside in the alimentary tract and hemolymph fractions only. All rabbits which were skin tested were found to exhibit delayed hypersensitivity and to have serum precipitins with specificity against these antigens. Passive cutaneous anaphylaxis activity was demonstrated only in sera from rabbits also exhibiting reaginic and/or Arthus-type skin hypersensitivities. With the use of immunoelectrophoresis four separate antigens were demonstrated in alimentary tract fractions. Larval dissections revealed the alimentary tract to be filled with cellular elements of rabbit whole blood. The immunologic findings are discussed in relation to this newly recognized feeding pattern and it is proposed that sensitization of the host occurs as a consequence of exogenous larval secretions injected at the time of feeding.     

An isolated abdominal preparation in the rat

A methodological approach proposed lies in the use of a complex abdominal preparation (an alimentary complex) of the gastrointestinal tract containing rat stomach, duodenum, small and large intestines and pancreas. The method is based on perfusion of the preparation vessels, namely of the vessels of the gastrointestinal tract or its parts both in situ and isolation of this alimentary complex. The alimentary complex is intended for solution of many problems of normal and pathological physiology, pharmacology and biology, permitting a deeper and broader insight into alimentary, transport, endocrine and regulatory functions of the gastrointestinal tract.     

Digestion of zooplankton in the alimentary tract of vendace (Coregonus albula) larvae

The degradation of zooplankton eaten by vendace larvae was investigated by cutting their tubiform alimentary tract into four quarters and analysing the contents separately. Soft-bodied rotifers were found to degrade and become indistinguishable in the anterior part of the alimentary tract, while cladocerans and copepods could still be identified in the posterior part. Assessing the diet of a larva on the basis of its whole alimentary tract contents was found to give biased results. More reliable estimates of the proportions of zooplankton taxa in the diet could be achieved from the first quarter of the alimentary tract.     

Quantitative studies on trypanosomes in tsetse tissue culture

Tissues from pupae of Glossina morsitans of various ages were cultured in modified Trager's medium. Cellular outgrowths were produced from explants of proventriculus, brain, and imaginal body wall and large vesicles were extruded from pieces of midgut of young pupae. Complete alimentary tract from older pupae displayed rhythmic contractions for up to 3 weeks. When Trypanosoma brucei and T. congolense in mouse blood were added to hanging drop cultures of tsetse tissues and incubated at 28 C, the organisms multiplied and changed into forms morphologically similar to those found in the tsetse fly midgut. The trypanosomes were maintained for 30 days by serial passage at 5-day intervals. The growth of T. brucei in the presence of different pupal tissues was studied. Of all the tissues tested the complete alimentary tract from pupae older than 21 days gave the best results. Growth also occurred when the trypanosomes were separated from the insect tissue by a semipermeable membrane. The trypanosomes failed to grow in (a) culture medium alone, (b) media containing extracts of alimentary canal and (c) medium in which alimentary tract had been cultured for 3 or 4 days.     

Calcitonin-like immunochemical staining in the alimentary tract of Ciona intestinalis L.

Summary Calcitonin-like immunoreactivity has been found with the peroxidase-anti-peroxidase (PAP) method in cells of the epithelium of the alimentary tract as well as in nerve cells and nerve fibers in the connective tissue underlying the epithelium of the alimentary tract of Ciona intestinalis L. The nature of these cells is discussed with reference to endocrine-like cells found in the alimentary tract of other protochordates and to the possible dual role of calcitonin occurring in the gastroenteropancreatic system, on the one hand, and in the nervous system, on the other.     

儿童过敏性紫癜合并消化道出血的影响因素分析

目的:探讨过敏性紫癜合并消化道出血的相关危险因素。方法:回顾性分析2013年9月至2016年6月在武汉协和医院儿科住院治疗的80例过敏性紫癜初诊患儿的临床资料,根据是否合并消化道出血分为消化道出血组11例,非消化道出血组69例,比较两组患儿的年龄、地区、性别、发病季节、紫癜分布特征、是否合并紫癜性肾炎、hsCRP、ESR、血常规、生化等。结果:与非消化道出血组相比,消化道出血组患儿的发病季节、血清超敏C反应蛋白(hsCRP)、血清钙离子(Ca)水平差异均有统计学意义(P0.05),两组紫癜性肾炎发病率比较差异无统计学意义,但消化道出血组合并紫癜性肾炎的比例(45.5%)明显高于非消化道出血组(21.7%)。结论:夏冬季节、高水平血清CRP、低水平血清Ca~(2+)是过敏性紫癜患儿合并消化道出血的危险因素。     

The contribution of gastrointestinal microbiota in the existence of type 2 diabetes in Saudi Arabia: Current information and perspectives

Diabetes mellitus (DM) is a genuine international health issue, with Saudi Arabia ranking among the top nations with the largest diabetes prevalence. Following the International Diabetes Federation (IDF), 3.8 million Saudi Arabian people had diabetes in 2014. The occurrence of diabetes in Saudi Arabia is likely to elevate due to the current trend in the general rise of socio-economic status, which positively correlates with diabetes prevalence. The incidence of Type 2 diabetes (T2D) is highest within the age group ≥ 45 years, especially in Riyadh and Jeddah, the metro cities of Saudi Arabia. Previous studies have shown that the incidence of T2D is larger in urban regions (25.5%) than in rural regions (19.5%). Both Riyadh and Jeddah are urban areas with different food habits and locations in Saudi Arabia. Recent studies have indicated the correlation between altered alimentary tract microbiota with type 2 diabetes. Gut microbiota plays a critical role in degrading undigested dietary compounds and releasing a vast array of metabolites that directly and indirectly affects host health. In the current review, we shed light on the state of information on the realization of the types and functions of the alimentary tract microbiome and how it plays a causative agent in the up growth of T2D.     

Beyond diversity: functional microbiomics of the human colon

Molecular tools have revealed wide microbial diversity in the human alimentary tract. Most intestinal microorganisms have not been cultured and the in situ functions of distinct groups of the intestinal microbiota are largely unknown but pivotal to understanding the role of these microorganisms in health and disease. Promising strategies to gain more insight into the functionality of the complex microbial communities in the human alimentary tract, including fermentation processes in the colon, are discussed. These research approaches could provide a basis for the definition of a healthy gut based on key properties of microbial functionality. This will also enable the development of direct nutritional strategies for intestinal disease prevention and health promotion.     

Ultrastructure of alimentary tract formation in embryos of two insect species: Melasoma saliceti and Chrysolina pardalina (Coleoptera, Chrysomelidae)

Embryogenesis of the alimentary tract in two chrysomelid species (Chrysolina pardalina and Melasoma saliceti) is described. The embryonic development of both species lasts 7days at room temperature. Stomodaeum and proctodaeum invaginate at the anterior and posterior ends of the germ band. Together with the ectodermal tissue the endoderm cells also enter into the embryo. The anterior and posterior parts of the alimentary tract wedge into the yolk in the form of conical structures. The endodermal cells remain at the yolk surface and start migration over the yolk mass as two lateral bands of cells. The endoderm is always accompanied by mesoderm. On the fifth day of development the endodermal cells together with the mesoderm layer spread over the ventral and dorsal sides of the yolk mass and form the single layered primordium of the midgut epithelium. On the sixth day of development a basal lamina appears between the endoderm and the mesoderm cells and differentiation of both tissues starts. The endodermal epithelium cells change shape from flat to cuboidal and eventually into columnar. Mesoderm cells differentiate into muscle and tracheae. On the 7thday of development stomodaeum and proctodaeum become lined with cuticle and the midgut becomes covered with microvilli. The yolk cells populating the yolk mass do not contribute to midgut formation in the species studied.     

Cell renewal in the epithelium of the alimentary tract of the larval lamprey,Petromyzon marinus L.

Light microscopic autoradiography with ³H-thymidine demonstrates that the three regions of the alimentary tract in the larval (ammocoete) lamprey, Petromyzon marinus L., possess different patterns for renewing their epithelium. In the oesophagus, columnar and mucous cells originate from stem cells located at the bases of folds and migrate to the tops of the folds where they are apparently extruded. Ciliated cells, located only at the tops of the folds, seem to differentiate from migrating columnar cells. In the anterior intestine, stem cells are present throughout the epithelium so that there is limited migration of cells and their extrusion occurs randomly. In the posterior intestine, the stem cells located at the bases of the typhlosole provide a continuous population that differentiates and migrates to the top of the typhlosole and to the opposite epithelial wall where they are presumably extruded. The rates of cell renewal in all three epithelial regions of the alimentary tract are slower in animals maintained at 10 ± 1°C compared with those kept at 21 ± 1°C. Comparatively, ammocoetes have the least specialized system for cell renewal known in the alimentary tract of a vertebrate.     

Establishment of a poliovirus oral infection system in human poliovirus receptor-expressing transgenic mice that are deficient in alpha/beta interferon receptor

Poliovirus (PV) is easily transferred to humans orally; however, no rodent model for oral infections has been developed because of the alimentary tract's low sensitivity to the virus. Here we showed that PV is inactivated by the low pH of the gastric contents in mice. The addition of 3% NaHCO3 to the viral inoculum increased the titer of virus reaching the small intestine through the stomach after intragastric inoculation of PV. Transgenic mice (Tg) carrying the human PV receptor (hPVR/CD155) gene and lacking the alpha/beta interferon receptor (IFNAR) gene (hPVR-Tg/IfnarKO) were sensitive to the oral administration of PV with 3% NaHCO3, whereas hPVR-Tg expressing IFNAR were much less sensitive. The virus was detected in the epithelia of the small intestine and proliferated in the alimentary tract of hPVR-Tg/IfnarKO. By the ninth day after the administration of a virulent PV, the mice had died. These results suggest that IFNAR plays an important role in determining permissivity in the alimentary tract as well as the generation of virus-specific immune responses to PV via the oral route. Thus, hPVR-Tg/IfnarKO are considered to be the first oral infection model for PV, although levels of anti-PV antibodies were not elevated dramatically in serum and intestinal secretions of surviving mice when hPVR-Tg/IfnarKO were administered an attenuated PV.     

Growth-phase dependent substrate adhesion in Crithidia fasciculata

Crithidia fasciculata is a trypanosomatid flagellate that parasitizes several species of mosquito. Within the alimentary tract of its host, C. fasciculata exists in two forms: one is a non-motile form, attached in clusters to the lining of the gut, the other a more elongated form swimming freely in the gut lumen. We have developed an in vitro culture system that reproduces the appearance of these two distinct morphological forms. Using two different cultivation methods, shaking and stationary incubations, we have demonstrated that adherence phenotypes are growth-phase dependent. Organisms in the logarithmic phase of growth possess the ability to adhere to substrates; this ability is lost when the organism enters a stationary growth phase. Parasite adherence was independent of cultivation method or substrate. Furthermore, adherent forms of Crithidia maintained their adhesive properties following their removal from substrates. Our data reveal a growth-phase-regulated process of cell attachment that may influence the transmission and dissemination of this parasitic flagellate.     

Gastro-intestinal and neurohormonal peptides in the alimentary tract and cerebral complex ofCiona intestinalis (Ascidiaceae)

Summary Polypeptide-hormone producing cells were localized in the alimentary tract and cerebral ganglion ofCiona intestinalis using cytochemical, immunocytochemical and electron-microscopical methods.Antisera to the following peptides of vertebrate type were employed: bombesin, human prolactin (hPRL), bovine pancreatic polypeptide (PP), porcine secretin, motilin, vasoactive intestinal polypeptide (VIP),-endorphin, leu-enkephalin, met-enkephalin, neurotensin, 5-hydroxytryptamin (5-HT), cholecystokinin (CCK), human growth hormone (GH), ACTH, corticotropin-like intermediate lobe peptide (CLIP) and gastric inhibitory peptide (GIP).Immunoreactive cells were found both in the alimentary tract epithelium and in the cerebral ganglion for bombesin, PP, substance P, somatostatin, secretin and neurotensin. Additionally, in the cerebral ganglion only, there were cells immunoreactive for-endorphin, VIP, motilin and human prolactin. 5-HT positive cells, however, were restricted to the alimentary tract.No immunoreactivity was obtained either in the cerebral ganglion or in the alimentary tract with antibodies to leu-enkephalin, met-enkephalin, CCK, growth hormone, ACTH, CLIP and GIP. Prolactin-immunoreactive and pancreatic polypeptide-immunoreactive cells were argyrophilic with the Grimelius' stain and were found in neighbouring positions in the cerebral ganglion.At the ultrastructural level five differently granulated cell types were distinguished in the cerebral ganglion. Granules were present in the perikarya as well as in axons. The possible functions of the peptides as neurohormones, neuroregulators and neuromodulators are discussed.