江豚染色体的初步研究

江豚是一种广泛分布于浅海和河湾的无背鳍豚。其分类学研究[b]、说明该属中有多个种。分布在我国沿海和长江中的江豚,过去曾被认为与日本的江豚同属一种,命名为Neophocaena asiaeorientalis。有关它的染色体组型     

江豚和白鱀豚视网膜神经节细胞的研究

江豚和白暨豚视网膜神经节细胞根据其形态结构可分为1、2两型。其密度分布在大多数江豚和1头白(既鱼)豚呈两个高密度区。第一高密度区位于视网膜鼻侧偏腹方,第二高密度区位于颞侧偏背方。第一和第二高密度区的细胞的最高密度在江豚大多数分别为每平方毫米250和210左右,在一例白暨豚约180和140以上。其组成、密度分布及细胞总数在采自长江和黄海沿岸的江豚之间差异不显著。在白(既鱼)豚由于大神经节细胞相对增多,细胞平均直径比江豚的大;细胞数在40微米左右处形成特有的第二个峰;2型的细胞极少,且没有发现典型的星形神经节细胞。 几种豚类的视网膜神经节细胞的比较表明,在适应弱光环境的过程中,视网膜神经节细胞的组成发生了一些改变:2型的神经节细胞逐渐减少甚至消失;大神经节细胞相对增多;神经节细胞密度减小。视觉敏度提高,锐度下降。     

长江下游南京至贵池江段白鱀豚的观察

白鱀豚(Lipotes vexillifer)在长江下游自湖口至长江口都有分布。长江下游白鱀豚的生态观察始自1979年,但并未中断。其后南京至贵池间约250公里的长江段的观察,更有日本琉球大学名誉教授西胁昌治博士和鸟羽水族馆副馆长片罔照男于1981年3月15-21日参加了工作。现作简短报道。 1979年8月20日在太阳洲主航道中见到白鱀豚1头,次日该江段北岸群众两次发现白鱀豚在岸边游过。这一时期的白鱀豚不易跟踪观察,它们出水呼吸几次后,即消灭在远处。观察中也见到江豚(Neophocaena)10余头。1980年2月22日在太阳洲江段见到江豚两头,未发现白鱀豚。当天13:30在土桥附近见2头白鱀豚成体和1头幼体。它们在此活动了40分钟以上。2月24日返经太阳洲时见1头,白暨豚,另有4头江豚0 1981年春,联合考察船于3月15日自南京启航0 16日傍晚在芜湖附近的白茹沙江段见到江豚一群约10-12头,18日在接近土桥时又见到数头。19日上午在太阳洲见江豚一群约10余头。中午到达大通江面,先遇见数头江豚,接着见到一群带有幼体的白暨豚共约8-10头在近北岸处觅食。约40分钟后,此群离去,在附近又见到江豚6头左右。3月19日下午在梅龙和贵池及3月20日上午在梅龙也都见到江豚。据渔民报告,3月19日下午在白茹沙见到白暨豚在江中活动。1981年7月6日的观察中,在新港附近发现白暨豚2头,江豚3头。其中1头江豚背着幼豚。接着又在黑沙洲洲头附近遇见白暨豚3头。次日上午在近土桥外观察到白暨豚4头,江豚2头。     

铜陵长江大桥对豚类栖息地的影响

根据1987-2001年在铜陵江段所进行的18次豚类生态考察,统计历年考察记录中,在成德洲-梅埂段（以下称大桥河段）工作的天数及观察到的白Ji豚和长江江豚数量,分别计算其SPUE值（Sightings per unit of effort,以头/d计）。并于1989,2001年,在长江水位8.5m左右（吴淞 高程）测定了大桥河段断面A,B,C,D的深度（m)及流速（m/s)。根据汉道最大河宽（B）,转折角（α）,曲折率（S/L）,以及汊道宽长比（B/S）的变化,分析河道与沙洲的变动对白Ji豚和长江江豚栖息地的影响。研究结果表明大桥建成后,河段平面变形小,汊道分流比稳定,滩槽很少变动,流态稳定,水势复杂多样,仍具备豚类栖息活动必要的水文条件,但铜陵大桥对其上下河道,沙洲也产生了一定的影响,主要表现为近期和悦洲与成德洲附近的滩槽冲淤明显,汇,分流区主流摆动不确定,不能形成稳定的水区,导致成德洲附近的白Ji豚和长江江豚活动次数明显减少,特别是白Ji豚的活动路线中（太阳洲→梅埂）的羊山矶,历次考察中未观察到白Ji豚,总而言之,白Ji豚在大桥河段的SPUE值降低与其种群急剧下降是一致的,但在梅埂活动的次数下降不明显;长江江豚在局部水域（梅埂,横港）的SPUE值有上升趋势,这些现象可能与近期的河床演变及桥墩挑流有关。     

白边油蝠表皮角质化细胞末端分化的超微结构

蝙蝠是一种唯一能够飞行的哺乳动物,其皮肤的超微结构尚未见报道。在电镜下观察了白边油蝠(Pipistrellus kuhlii)背部和翼膜皮肤的超微结构。表皮的厚度较低(10~12μm),角质层下有1~2层的刺细胞,该刺细胞由相似于鸟类无羽表皮的纤细角化细胞形成。颗粒层不连续且仅有少量小型透明角质颗粒(<0.3μm)。在翼膜的若干区域,表皮简化为一层与角质层相连的基底层。过渡期的角化细胞几乎不存在,提示其角质化过程非常迅速。基底膜上的无数半桥粒在真皮下面形成密集的附着点。大量胶原纤维直接维系在半桥粒和基底膜的致密层上,稀疏的弹性纤维使得蝙蝠表皮在飞行时易于伸展、在飞行后易于迅速折叠而不会受到损伤。与鸟类的表皮相似,蝙蝠角化细胞富有大量的脂质。由于脂质有助于蝙蝠皮肤在飞行中与冷空气流的传热绝缘,大量脂质的存在可能是为补偿蝙蝠翼膜的真皮缺乏厚的脂肪层。研究还表明,毛发较薄(4~7μm),并具有与皮层相似的突状物组成的精细表皮,其表皮细胞形成钩状抓握点使毛发紧紧粘结在一起,通过这种方式毛皮保持紧凑以恒定体温。     

江豚表皮超微结构的研究

本文用透射电镜和扫描电镜对捕自莱州湾的两头江豚表皮的超微结构作了观察。见其表皮中MCG的板层结构与海豚的有所不同,MCG内容物排出到细胞间隙形成表皮屏障。其黑素颗粒可能通过黑素细胞的突起与角蛋白细胞相接触处胞膜的消失出现缺口的方式输入角蛋白细胞。并对江豚表皮的不全角化现象等问题进行了讨论。     

江豚背部小齿的超微结构与功能

长江江豚背部皮肤表面有一长条小齿,由1—3排组成。它是由表皮向体表突起而成。小齿区皮肤中的乳头深深伸入表皮,几达表面,它的高度在成体约占整个表皮厚度的70—80%,新生幼儿为84.6%。经研究,我们发现在小齿区皮肤中存在着大量类似于人类皮肤中的环层小体那样的被囊神经末梢和几种有鞘神经纤维束。根据这些结构,我们认为小齿是一种感觉器官,它并不能起到防止幼儿从母体背部滑落的作用。       

江豚背部小齿的超微结构与功能

长江江豚背部皮肤表面有一长条小齿,由1—3排组成。它是由表皮向体表突起而成。小齿区皮肤中的乳头深深伸人表皮,几达表面,它的高度在成体约占整个表皮厚度的70-80％,新生幼儿为84．6％。经研究,我们发现在小齿区皮肤中存在着大量类似于人类皮肤中的环层小体那样的被囊神经末梢和几种有鞘神经纤维束。根据这些结构,我们认为小齿是一种感觉器官,它并不能起到防止幼儿从母体背部滑落的作用。     

半自然条件下成年雌性长江江豚的抚幼行为

2014年5-9月,采用目标动物取样法,对栖息在铜陵淡水豚国家级自然保护区半自然水域的两头成年雌性长江江豚分娩后4个月内的抚幼行为进行观察。结果表明,母豚有5种明显的抚幼行为,其中以护领行为和携带行为为主,托举行为、返回行为和干涉行为发生频率较低;随着幼豚发育,托举、携带、干涉行为呈下降趋势;护领行为先上升,后趋于平稳;返回行为变化相对平稳,但在幼豚2月龄左右出现一个高峰。此外,两头母豚间的干涉和返回行为发生频率差别较大。综合以上结果可见,出生后约两个月内是半自然水域长江江豚抚幼的关键时期,应在此期间加强管理。     

矮生菜豆胚乳细胞形成时的超微结构研究

应用透射电镜对矮生菜豆的游离核胚乳、胚乳细胞及珠被绒毡层的超微结构进行了观察,揭示了胚乳细胞化过程中自由生长壁的形成方式。实验表明,在游离核胚乳中存在大量有被小泡,胚乳游离核的外层核膜发生明显外突并以出芽的方式产生有被小泡。初始胚乳细胞壁为自由生长壁,大量有被小泡融合于自由生长壁末端使之不断延伸并产生分枝。与珠被绒毡层相邻的胚乳细胞产生发达的壁内突,具有传递细胞特征;在这些细胞中出现大量的核糖体及粗糙内质网,表现现高度的合成活性。     

Nerves and nerve endings in the skin of tropical cattle.

The nerves and nerve endings in the skin of tropical cattle were studied using histological and histochemical techniques. Many nerve trunks and fibres were present in the reticular and papillary dermis in both hairy and non-hairy skin sites. In non-hairy skin locations such as the muzzle and lower lip, encapsulated endings akin to Krause and Ruffini end bulbs, which arise from myelinated nerve trunks situated lower down the dermis were observed at the upper papillary layer level. Some fibre trunks seen at this level extended upwards to terminate within dermal papillae as bulb-shaped longitudinally lamellated Pacinian-type endings, while other onion-shaped lamellated nerve structures were located either within dermal papillae or near the dermo-epidermal area. Intraepidermal free-ending nerve fibres, appearing non-myelinated were observed in areas with thick epidermis. Intraepidermal free-ending nerve fibres, appearing non-myelinated were observed in areas with thick epidermis. On hairy skin sites, however, organized nerve endings or intraepidermal nerve endings were not readily identifiable.     

Some observations on the fine structure of the sinus gland of a land crab,Gecarcinus lateralis

The dilated axon endings of the sinus glands of the brachyuran crab, Gecarcinus lateralis, are filled with homogeneously dense granules, each granule being bounded by a delicate membrane. The granules are of two orders of magnitude: 0.05 to 0.1 micro and 0.15 to 0.2 micro in diameter. Each axon ending contains granules of a nearly uniform size. Endings with granules of the larger size range predominate. Non-nervous cells endogenous to the sinus gland are scattered among the nerve endings. The cell contours are irregular, and cytoplasmic processes ramify between endings. The axons are unmyelinated, having only thin limiting membranes, and they possess many neurofibrils. Granules in preterminal portions of the axons tend to lie at the periphery of the fiber, and in some cases in chains at the core of the fiber. The granules appear to be storage and release centers for neurosecretory substances or their precursors.     

江豚胎儿形态发生及生殖规律的研究

在胚胎发育早期,江豚上颌生有短须;左侧1-3根,右侧2-3根.具有半月形外耳廓.雄性胎儿阴茎露于体外.脐带较短.胎儿运动器官(胸鳍、尾鳍和尾柄)发育较快.随着胚胎的发育,外耳廓消失,阴茎藏于体腔.江豚胚胎发育过程中的这些形态学变化,再现了鲸类祖先在陆上生活的历史,同时也反映了鲸类在二次入水过程中所形成的对水环境的适应.此外.通过对收集的17头江豚胎儿资料进行统计,结果表明长江江豚胎儿的生长速度约为9.08cm/月(O.303cm/d),妊娠期为9.4个月,交配季节为6-8月份,分娩为3-5月份.       

Ultrastructural and immunocytochemical studies of neuromuscular junctions in oviduct of Locusta migratoria

The ultrastructure of nerve endings in the oviduct visceral muscles of Locusta migratoria was studied by electron microscopy and by immunogold labeling for two kinds of neuromodulators, the pentapeptide proctolin and FMRFamide-related peptides. Nerve endings contained electron-lucent round vesicles and two kinds of granules (round and avoid), and formed two types of synapses or release sites with the muscle. The morphologically distinct nerve endings were classified into three different categories based on the composition of synaptic vesicles and granules. Type-I nerve endings were dominated by electron-lucent round vesicles and contained only a few round electron-dense granules. Type-II nerve endings contained mostly electron-dense round granules and electron-lucent round vesicles. A few electron-dense ovoid granules were also present. Electron-dense ovoid granules dominated the type-III nerve endings, which usually contained less electron-lucent vesicles than either type-I or II nerve endings. Both proctolin and FMRFamide-like immunoreactivity was associated with electron-dense round granules. However, FMRFamide-like immunoreactivity was only found in the type-II nerve endings, while proctolin immunoreactivity was found within type-I nerve endings as well as in some type-II nerve endings. Immunological results therefore allow us to further divide type-II nerve endings into type-IIa (immunonegative for proctolin) and type-IIb (immunopositive for proctolin). Type-III nerve endings show no immunolabeling to either proctolin or FMRFamide.     

Some Observations on the Fine Structure of the Sinus Gland of a Land Crab, Gecarcinus lateralis

The dilated axon endings of the sinus glands of the brachyuran crab, Gecarcinus lateralis, are filled with homogeneously dense granules, each granule being bounded by a delicate membrane. The granules are of two orders of magnitude: 0.05 to 0.1 µ and 0.15 to 0.2 µ in diameter. Each axon ending contains granules of a nearly uniform size. Endings with granules of the larger size range predominate. Non-nervous cells endogenous to the sinus gland are scattered among the nerve endings. The cell contours are irregular, and cytoplasmic processes ramify between endings. The axons are unmyelinated, having only thin limiting membranes, and they possess many neurofibrils. Granules in preterminal portions of the axons tend to lie at the periphery of the fiber, and in some cases in chains at the core of the fiber. The granules appear to be storage and release centers for neurosecretory substances or their precursors.     

Calcitonin gene-related peptide (CGRP) immunoreactivity in the neuroendocrine Merkel cells and nerve fibres of pig and human skin

Summary The presence of calcitonin gene-related peptide (CGRP) in the skin of pig snout and human fingertip was investigated using immunohistochemical techniques. CGRP immunoreactivity was found in Merkel cells and nerve fibres of both species. In pig snout skin, Merkel cells containing CGRP were seen forming clusters at the tips of rete ridge epidermis and in the external root sheath of sinus hair follicles (vibrissae). Human Merkel cells immunostained for CGRP were found isolated or forming small groups in the basal layer of glandular epidermal ridges. In all cases, immunoreactivity was more intense on the side of the Merkel cell facing the associated nerve terminal (which was never positive for CGRP). This part of the Merkel cell has the greatest density of dense-cored granules, suggesting that CGRP must be stored in these granules. Nerve, bundles containing CGRP-immunoreactive fibres were found at dermal and hypodermal level, and blood vessels were often surrounded by CGRP nerve fibres. In pig snout skin some nerve fibres containing CGRP penetrated the epidermis and terminated as free endings, and in the human fingertip a small number of CGRP-immunoreactive nerve fibres were seen in Meissner's corpuscles.     

Calcitonin gene-related peptide (CGRP) immunoreactivity in the neuroendocrine Merkel cells and nerve fibres of pig and human skin

The presence of calcitonin gene-related peptide (CGRP) in the skin of pig snout and human fingertip was investigated using immunohistochemical techniques. CGRP immunoreactivity was found in Merkel cells and nerve fibres of both species. In pig snout skin, Merkel cells containing CGRP were seen forming clusters at the tips of rete ridge epidermis and in the external root sheath of sinus hair follicles (vibrissae). Human Merkel cells immunostained for CGRP were found isolated or forming small groups in the basal layer of glandular epidermal ridges. In all cases, immunoreactivity was more intense on the side of the Merkel cell facing the associated nerve terminal (which was never positive for CGRP). This part of the Merkel cell has the greatest density of dense-cored granules, suggesting that CGRP must be stored in these granules. Nerve bundles containing CGRP-immunoreactive fibres were found at dermal and hypodermal level, and blood vessels were often surrounded by CGRP nerve fibres. In pig snout skin some nerve fibres containing CGRP penetrated the epidermis and terminated as free endings, and in the human fingertip a small number of CGRP-immunoreactive nerve fibres were seen in Meissner's corpuscles.     

Studies of Mechanoreceptors in Skin of the Snout of the Echidna Tachyglossus aculeatus

The echidna Tachyglossus aculeatus, together with the platypus, belongs to the monotremes, a group of mammals with a number of reptilian characteristics. A structure unique to the skin of monotremes is the push rod—a compacted column of epidermal cells that is 20 μm wide and 100 μm long with its tip at the skin surface, and that is able to move relatively independently of adjacent tissue. At the base of each push rod is a cluster of encapsulated nerve endings. Push rods are common in skin of the snout and have been postulated to have a mechanosensory function. Experiments were carried out on four anesthetized echidnas with the aim of determining the function of push rods. Recordings made from the infraorbital nerve, which supplies the skin of the upper jaw, yielded responses from a total of 46 afferents. Two were electroreceptors; the others were mechanoreceptors. Within the group of mechanoreceptors with rapidly adapting responses, three responded to high-frequency vibration and resembled pacinian corpuscles. There were 26 slowly adapting (SA) mechanoreceptors, which, based on the regularity of their discharge, could be divided into two groups: SA I or Merkel type, and SA II or Ruffini type. SA I receptors had very discrete receptive fields with diameters of 100 μm. The receptive fields of two SA I receptors were marked, and after histological processing, one was seen to lie near two push rods. It is concluded that mechanoreceptor responses in the echidna's snout skin resemble those in other mammals in many aspects. We could not unequivocally associate responses to mechanical stimulation with the push rods.     

ULTRASTRUCTURE OF THE CAROTID BODY

An electron microscope investigation was made of the carotid body in the cat and the rabbit. In thin-walled blood vessels the endothelium was fenestrated. Larger vessels were surrounded by a layer of smooth muscle fibers. Among the numerous blood vessels lay groups of cells of two types covered by basement membranes. Aggregates of Type I cells were invested by Type II cells, though occasionally cytoplasmic extensions were covered by basement membrane only. Type I cells contained many electron-opaque cored vesicles (350 to 1900 A in diameter) resembling those in endocrine secretory cells. Type II cells covered nerve endings terminating on Type I cells and enclosed nerve fibers in much the same manner as Schwann cells. The nerve endings contained numerous microvesicles (~500 A in diameter), mitochondria, glycogen granules, and a few electron-opaque cored vesicles. Junctions between nerve endings and Type I cells were associated with regions of increased density in both intercellular spaces and the adjoining cytoplasm. Cilia of the 9 + 0 fibril pattern were observed in Type I and Type II cells and pericytes. Nonmyelinated nerve fibers, often containing microvesicles, mitochondria, and a few electron-opaque cored vesicles (650 to 1000 A in diameter) were present in Schwann cells, many of which were situated close to blood vessels Ganglion cells near the periphery of the gland, fibrocytes, and segments of unidentified cells were also seen. It was concluded that, according to present concepts of the structure of nerve endings, those endings related to Type I cells could be efferent or afferent.