泰和乌骨鸡回肠显微结构及黏膜上皮机械屏障结构

泰和乌骨鸡是江西省特色禽类,具有重要的营养和药用价值,但有关其消化器官的超微结构研究甚少。本试验通过光镜和透射电子显微镜技术对乌骨鸡回肠及其肠上皮细胞进行了观察。结果表明,回肠壁分为黏膜、黏膜下层、肌层和外膜4层;肠绒毛密集;肌层发达,且在外肌层和外膜之间有大量黑色素颗粒分布;肠绒毛固有层和上皮细胞基部有肥大细胞分布;回肠上皮主要由单层柱状吸收上皮细胞构成,杯状细胞较少;吸收上皮细胞游离面纹状缘明显,胞质内有大量的吸收颗粒、线粒体和粗面内质网;上皮细胞侧面有紧密连接、黏着小带和桥粒构成的连接复合体,构成完整的黏膜上皮机械屏障。     

圈养黑熊胆囊的组织学研究

为了进一步探讨黑熊胆囊的组织学特点,试验采用组织学和组织化学方法对黑熊胆囊壁的微细结构进行观察。结果表明:黑熊胆囊壁是由黏膜、肌层、外膜构成,黏膜层分为黏膜上皮和固有层,黏膜上皮主要由单层高柱状上皮细胞构成,无杯状细胞,固有层结缔组织内含有较发达的由单层矮柱状上皮细胞围绕形成的管状腺;黏膜上皮和管状腺上皮细胞核均位于细胞中下部,核上胞质内均含有PAS反应强阳性颗粒,且在黏膜上皮表面和黏膜固有层管状腺腔内可见少量PAS阳性分泌物。肌层为平滑肌,肌纤维方向不规则。外膜为浆膜。     

成年牦牛扁桃体组织结构及免疫相关细胞分布

为了揭示成年牦牛扁桃体组织结构和黏膜免疫相关细胞的分布规律,本研究采用组织化学法、图像分析法与透射电镜技术,对牦牛扁桃体的形态特征及免疫相关组织与细胞的分布特征进行了详细的研究。结果显示,牦牛共有6个扁桃体,其基本结构主要由上皮层和固有层构成。口咽部扁桃体上皮主要由复层扁平上皮细胞组成,上皮组织结构紧密;鼻咽部扁桃体上皮主要由假复层纤毛柱状上皮细胞组成,在柱状细胞之间分布有大量的杯状细胞;二者上皮层细胞组成差异较大,厚度及上皮内淋巴细胞的数量差异极显著(P0.01)。并且,两者上皮下肥大细胞与淋巴小结的数量也差异极显著(P0.01)。电镜下,腭扁桃体与咽鼓管扁桃体上皮细胞间有大量的连接复合体,且咽鼓管扁桃体上皮细胞游离面有大量排列整齐的微绒毛。肥大细胞的胞质内聚集有许多高电子密度的颗粒。浆细胞核的周围有丰富的粗面内质网和核糖体,胞质中有黏液颗粒。结果表明,牦牛扁桃体组织结构和其他家畜基本相似,但扁桃体分布位置有所不同,且牦牛扁桃体免疫相关组织与细胞分布较丰富,其中腭扁桃体隐窝中分布有较多的杯状细胞,显示牦牛扁桃体具有更发达的黏膜免疫活性。     

牦牛大肠组织结构及黏膜免疫相关细胞的分布

为了揭示成年牦牛大肠结构和黏膜免疫相关细胞的分布规律,本研究采用光镜及透射电镜等技术,对牦牛盲肠、结肠和直肠组织结构及黏膜免疫相关细胞的分布与数量变化进行研究。结果显示,牦牛大肠壁由黏膜层、黏膜下层、肌层和浆膜构成。大肠黏膜上皮为单层柱状细胞及散在的杯状细胞,在直肠黏膜上皮中则有大量杯状细胞,黏膜上皮纹状缘不明显。固有层内含有大量肠腺和孤立淋巴小结,尤其在盲肠、结肠固有层孤立淋巴小结丰富,且生发中心明显,淋巴小结常伸入黏膜下层。大肠黏膜层平均厚度为(864.18±88.46)μm,其中结肠最厚,盲肠最薄,结肠与盲肠之间差异显著(P<0.01)。肌层分内环与外纵2层,结肠与直肠肌层发达,盲肠肌层最薄,盲肠肌层内环肌形成特殊的肌小结。上皮内淋巴细胞较多,以结肠最丰富,盲肠与结肠差异不明显,从结肠到直肠逐渐减少。盲肠有丰富的浆细胞,从盲肠、结肠至直肠依次减小。肥大细胞在结肠和盲肠均较多,在直肠则显著减少。超微结构显示,大肠黏膜上皮细胞之间有连接复合体,细胞游离面有许多排列整齐的微绒毛。上皮内淋巴细胞胞质少,胞核较大。肥大细胞胞质内有大小不等的高电子密度圆形颗粒聚集。研究表明,牦牛大肠组织结构和其他反刍动物基本相似,但肠壁肌层厚,盲肠有特殊的肌小结,盲肠和结肠黏膜层分布着丰富的孤立淋巴小结和黏膜免疫相关细胞。     

重口裂腹鱼消化道黏膜的超微结构

用透射电镜技术对重口裂腹鱼消化道黏膜的超微结构进行了观察。结果显示:口咽腔和食道黏膜上皮均为复层上皮,上皮中存在大量粘液细胞,相邻细胞间通过发达的犬牙交错的桥粒紧密相连,表层和中间层细胞中有较多致密颗粒,表层细胞游离端表面有绒毛状突起。前肠吸收细胞微绒毛长而密,细胞质中线粒体、滑面内质网、粗面内质网、高尔基体发达。后肠吸收细胞微绒毛短而粗,终末网区中吞饮小泡较多。巨噬细胞中有多量溶酶体,其中见有凋亡细胞。2种形态的肥大细胞含大量分泌颗粒。肠黏膜上皮中存在少量凋亡细胞,其胞体、胞核和胞质均见有明显的形态学变化。     

成年牦牛小肠结构及黏膜免疫相关细胞数量变化研究

为了揭示成年牦牛小肠结构和黏膜免疫相关细胞的分布与数量变化的规律,本研究采用组织化学法、图像分析法及透射电镜技术,对成年牦牛小肠形态结构及上皮内淋巴细胞、杯状细胞、浆细胞和肥大细胞数量的变化进行了研究.结果表明:牦牛小肠壁由黏膜层、黏膜下层、肌层和浆膜构成.小肠中十二指肠绒毛高度/隐窝深度的比值最高、肌层最厚;空肠绒毛最高、隐窝最深;3段小肠绒毛高度、隐窝深度、绒毛高度/隐窝深度的比值和肌层厚度之间差异极显著(P＜0.01).牦牛小肠上皮内淋巴细胞数量由十二指肠向空肠、回肠逐渐减少,且差异极显著(P＜0.01),杯状细胞和肥大细胞数量也逐渐减少,而浆细胞数量则由十二指肠到回肠逐渐递增,且差异极显著(P＜0.01).电镜观察表明,牦牛小肠绒毛上皮细胞连接为紧密连接、缝隙连接和半桥连接,细胞游离面微绒毛丰富;上皮内淋巴细胞核大、胞质较少;杯状细胞呈典型高脚杯状,细胞顶端含有大量的分泌颗粒而膨大;浆细胞呈圆形或椭圆形,染色质沿核膜排列,胞质中有丰富的内质网;肥大细胞呈椭圆形,胞质内充满电子密度极强的大小不等的膜包颗粒.成年牦牛小肠结构特点能大大地提高了对高寒草地牧草的消化和吸收效率;而小肠各段有规律的分布了丰富的黏膜免疫相关细胞,显示牦牛小肠黏膜具有很强的黏膜免疫屏障功能.     

棘胸蛙消化系统组织形态学和组织化学的初步研究

为探讨棘胸蛙消化系统结构与食性功能的关系,采用解剖学、组织学、组织化学方法对其消化系统进行了宏观及显微结构观察。结果表明:棘胸蛙口咽腔含有纤毛柱状上皮、丰富的单细胞腺体和多细胞舌黏膜腺、颌间腺体,还有味蕾结构。食道具复层纤毛上皮,无味蕾,食道腺极发达。胃上皮黏膜层中有大量胃小凹和杯状细胞,具黏膜肌;胃腺发达,胃腺细胞胞质含嗜酸性颗粒,分泌黏液类型在贲门、胃体、幽门中主要呈Ⅲ-Ⅳ-Ⅲ型变化。十二指肠绒毛细长密集,回肠、直肠逐渐缩短,在黏膜层的固有膜中无小肠腺分布,肠壁较薄,杯状细胞在肠道各段较丰富,呈高—低—高变化。直肠黏膜上皮中含有巨型杯状细胞,固有膜有管状直肠腺散布。泄殖腔为复层立方上皮,具有泄殖腔腺。肝实质中肝小叶界限不明显,肝血窦丰富,肝内有大量色素细胞成团分布。胰脏独立存在,外分泌部胰腺组织发达,胰岛分散在其中。     

山羊胎期肺发育的形态学研究

对3～22周龄山羊胎儿肺进行了肉眼、光镜和透射电镜观察，结果表明：1．7～22周龄山羊胎儿肺的外部形态与胎龄无关，肺的外部形态以左二右四叶者为多见．肺的叶间裂和右肺副裂常不完整，以浆膜、肺组织或混合性组织(肺组织及浆膜)融合；2．山羊胎儿肺的发育分为5个时期：胚胎期(3～5周)肺芽分支形成主支气管，主支气管长度不断增长并萌芽出叶支气管，均衬以假复层柱状上皮。腺状期(6～12周)以支气管树发育为主，小支气管衬以假复层和／或单层柱状上皮；终蕾呈腺状，上皮细胞由假复层柱状逐渐变为单层柱状，胞核向细胞顶端移行；终蕾上皮细胞游离面可见短小的微绒毛；线粒体、粗面内质网及核糖体随着胎龄增加而逐渐增多，它们均位于细胞顶部。小管期(13～14周)以呼吸部发育为主，原始肺泡开始形成，呼吸性细支气管衬以未分化的立方上皮；终蕾腺状结构逐渐消失，终蕾上皮细胞由高矮不等的单层柱状上皮逐渐演变为立方形的原始肺泡上皮；细胞游离面可见较多的微绒毛，胞质内线粒体、粗面内质网及核糖体较发达。囊状期(第15周)呼吸部发育显著，肺内细支气管及其末端呈现出“充气”状态；部分原始肺泡上皮细胞分化为扁平的肺泡Ⅰ型细胞和立方形的肺泡Ⅱ型细胞；Ⅱ型细胞内出现嗜锇小体。肺泡期(16～22周)以肺泡的形成和分化为主，更多的肺泡上皮分化为扁平的肺泡Ⅰ型细胞和立方形的肺泡Ⅱ型细胞。此期，毛细血管内皮与部分肺泡上皮贴近，可将肺泡上皮细胞区分为3种：Ⅰ型细胞，呈矮柱状或椭圆形，胞质中有较明显的核糖体、扩张内质网及变性线粒体；形成了由Ⅰ型细胞一基膜一内皮细胞组成的气血屏障。Ⅱ型细胞，胞质内含丰富的嗜锇板层小体和核糖体，内质网扩张呈大小不一的泡状，多泡体出现，线粒体膨大变性，细胞游离面可见少数微绒毛。Ⅲ型细胞，为未分化细胞，呈立方形，胞体较小，胞核相对较大，呈圆或椭圆形，胞质少，呈带状．电子密度低，细胞器少。     

双峰驼胃底腺区黏膜组织学与组织化学研究

用组织学和组织化学研究方法重点观察了双峰驼胃底腺的细胞组成、分布及其组织化学特性。结果表明，双峰驼胃底腺区有发达的黏膜皱襞和厚的黏膜层，固有层中充满长而直的分支管状腺，由颈黏液细胞、壁细胞、主细胞和亲银细胞组成。颈黏液细胞分布在腺颈部，为混合黏液细胞，以分泌酸性糖共轭物为主。壁细胞十分丰富，分布于整个腺体，以腺体体部最多，细胞内含有酸性磷酸酶和碱性磷酸酶以及活性较强的非特异性醋酶，糖共轭物呈色均为阴性。主细胞位于腺体体部和底部，胞质中有大量的嗜碱性颗粒，含非特异性醋酶，但无糖共轭物。在黏膜褶顶部腺体体部和底部常看到不成熟的主细胞，其形态同颈黏液细胞和主细胞相似，为矮柱状或立方状，胞质有大量细小的颗粒，糖共轭物呈色反应和颈黏液细胞相似。糖共轭物呈色结果还显示，胃底腺区黏膜表面上皮仅分泌中性糖共轭物，胃小凹上皮和颊部腺上皮可分泌混合糖共轭物，胃小凹浅层上皮以中性糖共轭物为主，而底部上皮和颊部腺上皮以酸性糖共轭物为主。此外，在网状纤维染色时我们发现颈黏液细胞有明显的嗜银现象，核上胞质可见大量的嗜银颗粒，不成熟的主细胞有类似表现，但较其弱，颊部腺上皮也有较弱的嗜银性，而成熟的主细胞则无此特点，建议将此法作为颈黏液细胞和主细胞的鉴别方法。虽然双峰驼胃底腺区黏膜的微观结构及组织化学特性同其他动物和人有差异。但基本结构相似。     

诱导发情后母犬生殖器官组织学及组织化学观察

为了进一步探讨犬的生殖生理学,试验以诱导发情后母犬生殖器官为试验材料,采用组织学和组织化学技术,观察了诱导发情后母犬卵巢、输卵管和子宫的形态学特点。结果表明:诱导发情后犬卵巢外观呈葡萄串状,镜下可见大量黄体、少量原始卵泡和初级卵泡;诱导发情后母犬输卵管壁由黏膜层、肌层和外膜构成,黏膜上皮主要是由纤毛上皮细胞、分泌细胞构成的单层柱状上皮,黏膜固有层可见由纤毛上皮和分泌细胞围绕形成的管状腺,PAS反应可见分泌细胞的游离面和管状腺内有少量的阳性物质;诱导发情后母犬子宫壁由黏膜、肌层和外膜构成,黏膜上皮是单层柱状上皮,黏膜固有层内可见由单层柱状上皮构成发达的管状腺,子宫黏膜上皮细胞内含有少量PAS阳性物质,表面覆盖一层PAS阳性物质,而腺腔内含大量PAS阳性物质。     

泰山螭霖鱼肠道的显微和超微结构

采用光镜和扫描电镜技术 ,对泰山螭霖鱼 (Varicorhinusmacrolepis)的肠道进行了观察。结果表明 :泰山螭霖鱼无胃 ,食管之后是肠道 ,起始端膨大呈球状。肠道由前肠、中肠和后肠组成 ,肠管直径由前肠到后肠逐渐变小。各段肠壁均分为粘膜、肌层和浆膜 3层。粘膜上皮由柱状细胞和杯状细胞组成 ,肌层分内环行和外纵行 2层。粘膜向肠腔内突出形成许多粘膜褶 ,有的呈指状、杵状 ,有的有分支。由前肠到后肠 ,粘膜褶由高变低 ,数量逐渐减少 ;杯状细胞数目由多变少 ;肌层逐渐变薄。扫描电镜下 ,肠道的粘膜褶大体上呈纵向锯齿状 ,并且粘膜褶上还有次级皱褶。柱状上皮细胞表面多呈圆形 ,前肠、中肠柱状上皮细胞轮廓和界限清楚 ,常呈隆起状 ,而后肠上皮细胞表面较平坦。前肠柱状上皮细胞游离面的微绒毛长而密 ,后肠的短而稀疏。前肠的杯状细胞常常有较大的分泌孔 ,周围有分泌物 ,粘膜表面有粗大的分泌颗粒 ;后肠杯状细胞的分泌孔较小 ,粘膜表面有较多细小分泌颗粒。     

Ultrastructural Features of the Bovine Cecal Mucosa

The cecal surface epithelium of cattle was lined entirely by columnar cells except near the openings of the glands where a few partially depleted goblet cells were encountered. Surface columnar cells with pale cytoplasm, indented (sometimes dome-shaped) apical border and irregular microvilli, were also found near the gland orifices. Surface columnar cells -near the openings of the glands contained large cytoplasmic vacuoles and lysosomal-like bodies. Near the extrusion zone, however, the columnar cells contained highly indented and apically displaced nuclei. The glands were usually long and straight and lined by an epithelium concisting mainly of undifferentiated and goblet cells. There were few entero-endocrine and non-epithelial cells (intra-epithelial lymphocytes and globule leukocytes). Paneth cells were absent. The undifferentiated cells contained many free ribosomes and apical secretory granules. Some of these cells were undergoing mitotic division. Goblet cells exhibited a typical brandy-glass appearance and showed dark and light mucigenous granules. Endocrine cells with polymorphic secretory granules and cells with more uniform secretory granules were identified in the basal part of the epithelium. Globule leukocytes and intra-epithelial lymphocytes were usually encountered near the basal part of the epithelium. The lamina propria was highly cellular. It contained many plasma cells, mast cells and small lymphocytes, and few eosinophils, neutrophils and globule leukocytes. Some of the plasma cells contained large, dense Russell bodies within the cisternae of the rough-surfaced endoplasmic reticulum. The neutrophils displayed distinct populations of small and large cytoplasmic granules. Some of the eosinophilic granules showed narrow crystalline cores. Large lymphocytes were found in the lamina propria, but occurred less frequently than small lymphocytes.     

丁酸钠对肉鸡小肠黏膜免疫相关细胞的影响

本试验通过日粮中添加丁酸钠研究其对肉鸡小肠黏膜免疫相关细胞的影响.将32只1日龄健康AA肉鸡随机分为4个处理组:A组(对照组:基础日粮)、B组(丁酸钠组:基础日粮 500mg/kg丁酸钠)、C组(丁酸钠 芽孢杆菌组:基础日粮 100 mg/kg丁酸钠 200 mg/kg芽孢杆菌)和D组(丁酸钠 酶制剂组:基础日粮 100 mg/kg丁酸钠 500 mg/kg酶制剂).试验7周后,采用组织学技术研究肉鸡小肠黏膜免疫相关细胞的分布变化.结果显示:(1)与对照组比较,小肠肥大细胞、上皮内淋巴细胞及杯状细胞的形态无明显变化,肥大细胞多存在于肠腺周围和肠绒毛固有层,(2)各试验组的小肠肥大细胞、上皮内淋巴细胞及杯状细胞数均显著高于对照组(P<0.05);(3)各试验组和对照组小肠肥大细胞和上皮内淋巴细胞数均从前向后逐渐减少,十二指肠的肥大细胞最多,空肠的次之,回肠的较少;杯状细胞数则与之相反.由此可知,3种添加剂可不同程度地改善肉鸡小肠黏膜结构,且将丁酸钠分别与芽孢杆菌和酶制剂混合饲喂,效果在一定程度上好于单独饲喂丁酸钠.     

牛咽部组织结构的显微观察

[目的]运用组织学方法对3.5岁龄公牛咽部组织结构进行了观察与分析,以研究牛咽部不同部位显微结构。[方法]使用石蜡切片及HE和PAS染色在光学显微镜下观察牛咽部不同部位组织形态及细胞类型。[结论]牛鼻咽部黏膜层属于假复层柱状纤毛上皮结构,其间有大量的杯状细胞,没有角质层;喉咽部和口咽部属于复层扁平上皮结构,其间没有杯状细胞,有角质层。     

Light and electron microscopical observations on the terminal airways and alveoli of the lung of the SA (Cape) fur seal Arctocephalus pusillus

During activities of the Sea Fisheries Research Institute at Kleinzee, lung samples from six South African fur seals were collected. The terminal airways showed pseudostratified ciliated columnar epithelium with numerous goblet cells and occasional brush cells. Smooth muscle, cartilage and submucosal glands were also present. The epithelium changed over a short distance, in the smaller airways, through pseudostratified columnar non-ciliated to simple cuboidal epithelium with no goblet cells. The columnar non-ciliated cells contained secretory granules, which appeared to be serous. No Clara cells were found. Cartilage and muscle were present throughout, up to the origin of the alveolar ducts, but the glands disappeared together with the goblet cells. Alveoli were lined by types one and two alveolar epithelial cells, with subepithelial capillaries. They were divided by an alveolar septum with a well developed alveolar knob. This knob contained elastic fibres and fibroblasts, but not the smooth muscle cells which are present in terrestrial mammals and in Phocidae.     

Lectin histochemical characterisation of the porcine small intestine around weaning

The present study was undertaken to characterise the carbohydrate profile of the porcine small intestine using lectin histochemistry during the period from 3 days prior to weaning to 9 days post-weaning. A total of 56 piglets weaned at 4 weeks of age were included in the experiment. The most prominent changes in the glycosylation pattern were observed in the goblet cells. The highest lectin reactivity of the goblet cells in the crypts was observed 7 days post-weaning which suggests that the protective effect of the mucus layer against pathogenic bacteria is increasing during the postweaning period. The staining pattern of the apical membrane remained unchanged during the experimental period. This indicates that the glycosylation process in the goblet cells is rapidly inducible whereas changes in the glycosylation pattern of the apical membrane requires more time. The glycosylation pattern of both goblet cells and apical membrane differed between the positions of the small intestine. As glycoconjugates can act as attachment sites for microorganisms, these differences in the distribution of sugar residues may be one explanation for the site-specificity of certain pathogens.     

Histological Characteristics of the Tracheobronchial Tree of the Least Shrew (Cryptotis Parva)

The least shrew (Cryptotis parva) is a small vomit‐competent insectivorous species which has recently been introduced as an emesis animal model in the laboratory. In this study, the respiratory system of the least shrew was examined and compared with the well‐established larger species routinely used in the laboratory. Five least shrews (4–5 g body weight, 45–60 days old) were used. Standard histological procedures were followed for light microscopic examination. The lining epithelium of the trachea was found to be pseudostratified ciliated columnar (PSCC). Three types of cells were easily identified, basal and ciliated as well as few goblet cells interspersed among the ciliated cells and they were not clearly recognizable. A few tracheal seromucous glands were located at the free end of the C‐shaped cartilaginous rings. The cartilaginous rings are replaced by smooth muscle cells before the bronchi enter into the lung. The lining epithelium of tracheobronchial tree gradually changes into simple cuboidal epithelium that lacks goblet cells. However, the division of the tracheobronchial tree is similar to other mammalian species. On the other hand, the principal bronchus lacks cartilaginous plaques as it becomes intrapulmonary bronchus. The wall of the bronchi is supported by thick layers of spirally arranged smooth muscles. Two types of cells were readily recognizable: basal and ciliated cells, with rarely observed goblet cells. In addition, the PSCC epithelium changes into simple cuboidal much earlier in the bronchial division relative to other species.     

Histology and Ultrastructure of the Gut of the Tilapia (Tilapia spp.), a Hybrid Teleost

The morphology of the intestine has been studied in a species of warm water fish, Tilapia spp., a hybrid teleost of notable economic importance. Light and electron microscope results show that the intestine is a relatively undifferentiated muscular tube lined with a simple columnar epithelium interspersed with goblet cells. The proximal region has a greater surface area, manifested by elongated mucosal ridges. The enterocytes are covered apically with uniform microvilli and exhibit the typical ultrastructural features of pinocytosis, namely extensive invaginations of the luminal plasma membrane and massive accumulation of vesicles in the apical cytoplasm. The distal intestine mucosa is thinner and less elaborately folded and consists of columnar cells with shorter and sparser microvilli. Their supranuclear cytoplasm contains abundant clear vacuoles. Numerous endocrine cells can also be seen. Regional cellular ultrastructural features are correlated with digestive functions.     

Mucin biosynthesis in the bovine goblet cell induced by Cooperia oncophora infection

Mucin hypersecretion is considered to be one of the most common components of the immune response to gastrointestinal nematode infection. However, investigations have not been conducted in the Cattle–Cooperia oncophora system to verify the findings largely derived from murine models. In this study, we examined the expression of seven mucins and seven enzymes in the mucin biosynthesis pathway involved in O-linked glycosylation in the bovine small intestine including goblet cells enriched using laser capture microdissection during a primary C. oncophora infection. At the mRNA level, MUC2 expression was significantly higher in both lamina propria and goblet cells at 28 days post-infection compared to the naïve control. MUC5B expression at the mRNA level was also higher in lamina propria at 28 dpi. Expression of MUC1, MUC4, MUC5AC, and MUC6 was extremely low or not detectable in goblet cells, columnar epithelial cells, and lamina propria from both naïve control and infected animals. Among the seven enzymes involved in post-translational O-linked glycosylation of mucins, GCNT3, which may represent one of the key rate-limiting steps in mucin biosynthesis, was up-regulated in goblet cells, columnar epithelial cells, lamina propria, and gross small intestine tissue during the course of infection. Western blot analysis revealed that MUC2 glycoprotein was strongly induced by infection in both gross small intestine tissue and its mucosal layer. In contrast, the higher MUC5B protein expression was observed only in the mucosal layer. Immunohistochemistry provided further evidence of the mucin glycoprotein production and localization. Our results provided insight into regulation of mucin biosynthesis in various cell types in the bovine small intestine during gastrointestinal nematode infection and will facilitate our understanding of mucins and their role in immune response against parasitic nematodes.     

Histology,histochemistry and ultrastructure of the nasopharyngeal tonsil of the buffalo (Bubalus bubalis)

The light microscopic appearance and ultrastructure of the nasopharyngeal tonsil (tonsilla pharyngea), collected from 12 adult buffaloes of local mixed breed, were explored for the distribution of different types of epithelia, lymphoid tissue and high endothelial venules. The tonsillar mucosa was lined by pseudostratified columnar ciliated epithelium having goblet cells. The respiratory epithelium associated with the underlying lymphoid tissue formed the lymphoepithelium. The epithelium was further modified into follicle‐associated epithelium (FAE) characterized by reduced epithelial height, presence of a few dome‐shaped cuboidal cells equivalent of the M‐cells and absence of goblet and ciliated cells. The lymphoid tissue was distributed in the form of isolated lymphoid cells, diffuse lymphoid tissue and lymphoid follicles, mainly distributed within the propria‐submucosa along with the sero‐mucous glandular tissue. The goblet cells of the respiratory epithelium and the acinar cells contained different mucopolysaccharides. Scanning electron microscopy of the surface mucosa demonstrated a dense mat of cilia, island‐like arrangement of microvillus cells, M‐cells and a few brush‐like cells. The transmission electron microscopy revealed the different cell organelles of the respiratory epithelium and the FAE. Lymphocyte migration via the high endothelial venules in the propria‐submucosa was also observed.