共查询到20条相似文献，搜索用时 15 毫秒
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Fidiniaina Raharison Giovanni Mogicato Jean Sautet 《American journal of primatology》2009,71(8):647-653
The purpose of this study is to describe the anatomy and obtain echographic measurements of normal kidneys in brown lemurs (Eulemur fulvus). The anatomical findings show that brown lemur kidneys are comparable to those of rats except for an elongated papilla. The kidneys of 16 (7 females and 9 males) lemurs were examined with two‐dimensional and power Doppler ultrasonography under general anesthesia. Morphometrically, the left and right kidney surface areas are comparable (3.29 and 3.51 cm2). Kidney area has a significant linear correlation with body weight. Echo‐Doppler findings show that the mean renal arterial blood flow speeds for the left and right kidneys are comparable (0.70 and 0.73 m/s). However, flow speed is higher in the male (0.79 m/s) than in the female (0.60 m/s). The renal arterial diameters are between 1.0 and 1.8 mm. The fact that anesthesia can have hemodynamic effects on renal vasculature should be taken into consideration when assessing these echographic results. Am. J. Primatol. 71:647–653, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
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In this study, the functional morphology of the mandibular glands of pharaoh ant queens is investigated through histological and behavioural observations. The mandibular glands of queens of different age stages and mating status were examined at the light microscopical as well as the ultrastructural level. The results clearly show a high activity of the gland at the time of hatching, followed by a rapid degeneration independent of the queens' mating status. We therefore hypothesize the glandular secretion serves to stimulate workers to remove the queens' pupal skin. Experiments to compare hatching ability of isolated pupae and pupae assisted by workers confirmed the necessity of worker assistance, which is even more crucial to allow proper wing formation in queens and males. Together with the histological data, this suggests that the mandibular gland may indeed play a role in the social facilitation of hatching, although bioassays are required to give decisive answers about the mandibular gland's function. 相似文献
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The structure of the venom gland of Trachinus draco was studied by histological techniques using light microscopy. New structures in the large glandular cells were detected, including concentric cytoplasmic laminae, basal vesicles, silver nitrate staining cytoplasmic granules, and a high affinity for wheat‐germ agglutinin lectin in the cytoplasm of mature large glandular cells.We also describe morphologic changes of the venom gland during thermal test. At low temperatures, the large glandular cells and their nuclei become enlarged, whereas at high temperatures the large glandular cells are smaller and their nuclei irregular in shape. Similarly, samples from fish captured during two opposite seasons showed differences in their nuclei, which were smaller in summer than winter. The larger growth of supporting cells at low temperatures, together with their aggregation during conditions of stress and their vacuoles secretion, suggest that supporting cells could be played several roles. 相似文献
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Daisuke Saito Koji Tamura Yoshiko Takahashi 《Development, growth & differentiation》2017,59(7):593-602
The adrenal gland is an endocrine organ that plays essential roles in stress responses. This organ consists of two types of tissues, adrenomedulla and adrenocortex, deriving from different embryonic origins. Whereas it is well accepted that the adrenomedulla derives from neural crest cells, the origin of the adrenocortex remains elusive. In addition, the adrenocortex and gonads, two major steroid hormone‐producing tissues, have been thought to share the same origin, although the experimental evidence is lacking. In this study, to identify the origin of adrenocortex and to compare it to that of gonads, we scrutinized the medial portion of the coelomic epithelium (CE) after the lateral plate mesoderm has split into two CE components with a concomitant opening of the coelomic cavity in between them. We found that early medial CE consists of a two‐cell layer‐thick band of epithelial‐like cells, the outer and inner CEs. The outer CE faces the coelomic cavity, whereas the inner CE is juxtaposed to nascent blood vessels. Combining direct cell labeling with early molecular markers, we found that outer CE was the origin of the gonad but not the adrenocortex. The adrenocortex, instead, appears to derive from inner CE. Thus, the adrenocortical and gonadal progenitors are already segregated from each other when the coelomic cavity has opened. This study provides a new basis for understanding how the adrenal gland forms and how steroid hormone‐producing tissues arise during development. 相似文献
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本文对鸟类哈氏腺的解剖学、组织学及生理功能的研究进展进行了综述,对其未来的研究方向进行了展望,以期为此领域的研究提供参考。大多数鸟类哈氏腺的形态大体上无实质性差异,最常见的与家鸡相似：形状不规则,腺体被一层薄的结缔组织包膜隔成不同的小叶。根据小叶结构和排列在腺泡及小管的上皮细胞种类,鸟类哈氏腺可分为三类,即复管泡状腺,复管状腺和混合型腺,复管泡状腺中家鸡为代表,复管状腺中家鸭为代表,混合型中秃鼻乌鸦（Corvusfrugilegus ）为代表。腺体结构的类型可能与鸟类习性和行为有关。鸟类哈氏腺除最基本的润滑角膜和瞬膜功能外,还是B细胞活化和终末分化以及浆细胞增殖的场所,作为外周免疫器官,与脾脏、法氏囊和盲肠集合淋巴样组织一起构成决定鸟类全身和局部免疫反应的器官系统。 相似文献
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The impacts of Wasmannia auropunctata (the little fire ant) on the native biota and subsistence agriculture in the Solomon Islands are poorly understood. This species was originally introduced as a biological control against nut‐fall bugs (Amblypelta sp.) around 30 years ago and in the intervening time has spread throughout the Solomon Islands, aided movement of produce and planting material. It is now itself a major pest of coconut, cocoa and subsistence agriculture. In this study, we show the negative effects of this invasive ant on subsistence agriculture in the Solomon Islands. We do this by (i) assessing the presence of insect pests that develop a mutual relationship with W. auropunctata on four common subsistence crops; and (ii) measuring the impact of a significant pest (Tarophagus sp.) and its natural predator the bug Cyrtohinus fulvus, in the presence and absence of W. auropunctata on taro crops. The existence of insect pests that form a mutual relationship with W. auropunctata was measured in a total of 36 gardens of the four subsistence crops. This was conducted through standardized visual searches, plus identification and collecting from randomly selected plants within the gardens. A number of additional insect pests causing major problems to subsistence crops have also developed mutual relationships with W. auropunctata. Infested taro gardens have more Tarophagus sp. compared with taro plants that are free of the little fire ant. The presence and abundance of Wasmannia therefore has the potential to inflict considerable crop loss in rural subsistence gardens in the Solomon Islands. 相似文献
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Watchara Arthan Paweena Traiperm Stephan W. Gale Monthon Norsaengsri Lalita Kethirun 《Botanical journal of the Linnean Society. Linnean Society of London》2016,181(2):224-245
Hackelochloa is a pantropical genus of plant in the Poaceae, in which only two species have been included, H. granularis and H. porifera. Despite several morphological differences, notably the more prominent sculpturing of the lower glume and the larger dimensions of several quantitative traits, H. porifera has been reduced to the synonymy of H. granularis. Moreover, the status of the genus itself has been questioned, with a regional revision of the genus proposing inclusion of its members in the genus Mnesithea. In the present study, we investigated a range of morphological and anatomical attributes to assess critically the generic delimitation between Hackelochloa and Mnesithea. In clustering analysis, H. granularis, H. porifera and Mnesithea species were clearly resolved as three distinct groups with an R‐value of 0.98114. Likewise, three clusters representing these taxonomic units were revealed using principal component analysis (PCA), with the first two principal components highlighting key qualitative and quantitative characters. Scanning electron microscopy was used to reveal different patterns of sculpturing on the lower glumes in the two putative species and the ecological significance of these differences is inferred. The outline of leaf transverse sections, presence of parenchymatous tissue in the midrib region, number of adjacent bundles and number of chlorenchyma layers in the culm were also found to be diagnostic anatomical characters. This study supports the recognition of H. porifera as distinct from H. granularis and provides evidence that the genus Hackelochloa should be maintained. 相似文献
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Iigo Zuberogoitia Jos Enrique Martínez Jos Antonio Gonzlez‐Oreja Juan Manuel Prez de Ana Jabi Zabala 《Ibis》2019,161(4):878-889
Two hypotheses have been proposed to link population regulation to density‐dependent changes in demographical parameters: the habitat heterogeneity hypothesis (HHH) states that, as population density rises, an increasing proportion of individuals are forced to occupy low‐quality territories, which provokes a decline in average per‐capita survival and/or productivity although some individuals show no decline in fecundity; and the individual adjustment hypothesis (IAH), which suggests that increased densities lead to reductions in survival and/or fecundity by enhancing agonistic interactions, which affect all individuals to a similar extent. However, density‐dependent effects can be affected by density‐independent factors (DIF), such as weather. We test the effects of density dependence on annual reproductive success in Griffon Vultures Gyps fulvus at four spatial scales, nest‐site, cliff, colony and metacolony, in northern Spain from 2008 to 2015. Our results showed most support for the HHH at all scales. At the colony and cliff scale, IAH and DIF had similar importance, whereas there was little evidence of IAH at the metacolony and the nest scale. The best protected eyries (caves, potholes and sheltered ledges) produced the most fledglings and were used preferentially, whereas low‐quality eyries (exposed ledges or open crevices) were used only when the number of breeders increased. The significant interaction between breeding failure and density found for the more exposed eyries suggests that at higher densities, breeding pairs are forced to use poorer nesting areas, and the negative effect of density at the cliff scale could be due to the combined effect of a higher proportion of pairs using low‐quality eyries and the negative effect of rainfall. 相似文献
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PCR‐based methods are the most common technique for sex determination of birds. Although these methods are fast, easy and accurate, they still require special facilities that preclude their application outdoors. Consequently, there is a time lag between sampling and obtaining results that impedes researchers to take decisions in situ and in real time considering individuals’ sex. We present an outdoor technique for sex determination of birds based on the amplification of the duplicated sex‐chromosome‐specific gene Chromo‐Helicase‐DNA binding protein using a loop‐mediated isothermal amplification (LAMP). We tested our method on Griffon Vulture (Gyps fulvus), Egyptian Vulture (Neophron percnopterus) and Black Kite (Milvus migrans) (family Accipitridae). We introduce the first fieldwork procedure for sex determination of animals in the wild, successfully applied to raptor species of three different subfamilies using the same specific LAMP primers. This molecular technique can be deployed directly in sampling areas because it only needs a voltage inverter to adapt a thermo‐block to a car lighter and results can be obtained by the unaided eye based on colour change within the reaction tubes. Primers and reagents are prepared in advance to facilitate their storage at room temperature. We provide detailed guidelines how to implement this procedure, which is simpler (no electrophoresis required), cheaper and faster (results in c. 90 min) than PCR‐based laboratory methods. Our successful cross‐species application across three different raptor subfamilies posits our set of markers as a promising tool for molecular sexing of other raptor families and our field protocol extensible to all bird species. 相似文献
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Maria S. N. Volampeno Guy H. Randriatahina Riddhika Kalle Amy‐Leigh Wilson Colleen T. Downs 《African Journal of Ecology》2015,53(4):419-427
Population viability analysis is an important tool to assess the extinction risk in small populations of highly specialized primates. The blue‐eyed black lemur (Eulemur flavifrons) is critically endangered with a restricted range in the north‐western dry deciduous forest of Madagascar, where habitat fragmentation and loss of forest connectivity threaten its survival. We performed a population viability analysis (PVA) of this lemur in Ankarafa Forest in the Sahamalaza Peninsula National Park, north‐western Madagascar, to determine the demographic parameters most influential for population persistence and to assess extinction probabilities. We conducted PVA analyses using different demographic parameters which characterize the species including reproduction, lifespan and population size using the software VORTEX for six scenarios with 100 iterations and simulated over 100 years. The simulations suggested the first extinction within 13 years when the percentage of habitat destruction increased up to 12%. Severe habitat destruction such as fire and logging was the major cause which led to the risk of population extinction. Conservation strategies, in particular measures to reduce habitat destruction, are proposed to ensure the survival of this critically endangered lemur. 相似文献
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Juliane Vehof Sancia E. T. van der Meij Michael Türkay Carola Becker 《Acta zoologica》2016,97(1):117-126
Gall crabs are obligate associates of stony corals in which they induce skeletal modifications. In some cryptochirid species, females live in open depressions accessible to males; while in others, females are rather isolated in semiclosed galls, which necessitates elaborate sperm storage capabilities by the female. In this study we investigate the female gross morphology and reproductive systems of Fungicola syzygia lodged in semiclosed flattened pits, Opecarcinus cathyae with semiopen pits and Pseudocryptochirus viridis from shallow open depressions using line drawings and histological methods. The general morphology of the cryptochirids' reproductive systems is uniform and conforms to other thoracotreme brachyurans: paired muscular vaginae of the concave pattern lead from the sternal gonopores into paired seminal receptacles where sperm is stored. The seminal receptacle is internally lined by distinct types of epithelia: a cuticle underlined by a columnar epithelium ventrally, a monolayered secretory epithelium dorsally and a multilayered transfer tissue where the oviducts enter the seminal receptacle. In all studied specimens, the seminal receptacle contained free spermatozoa; however, in specimens of Pseudocryptochirus viridis it also contained spermatophores, indicating a recent insemination. In contrast to most other brachyurans ovaries of the investigated cryptochirids extend into the pleon. The specific degree of ovary extension differs between the studied species and is closely related to female body shape. 相似文献
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The legal and illegal use of organophosphorus and carbamate pesticides represents one of many threats to birds. The activity of the cholinesterase enzyme in plasma is used as a non‐destructive biomarker to diagnose the exposure of birds to these pesticides. Scavengers are one of the most important bird groups threatened by the use of baits poisoned with anticholinesterase pesticides. Knowledge of the characteristics of this enzyme in each bird species is crucial, as several studies indicate that more than one cholinesterase form may be present in the plasma of birds. In this study, cholinesterase activity was characterized in the plasma of the Eurasian Griffon Vulture Gyps fulvus by using several substrates and inhibitors of the enzyme, and its normal activity value was also determined. The in vitro sensitivity of Gyps fulvus plasma cholinesterase to carbamate insecticides (aldicarb, carbaryl and methomyl) was also investigated. The results indicated that propionylthiocholine iodide was the preferred substrate to determine plasma cholinesterase activity, followed by acetylcholine iodide and S‐butyrylcholine iodide, and acetylcholinesterase was the predominant enzymatic activity in Gyps fulvus plasma. Aldicarb was the most potent in vitro inhibitor of plasma cholinesterase activity in this species. However, cholinesterase enzymatic activity was significantly inhibited by all tested carbamates, providing further evidence that this biomarker is a suitable tool to monitor the exposure to these poisons in the field, highlighting its utility in conservation programmes. 相似文献
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《Feddes Repertorium》2018,129(2):123-136
In Microlicieae taxonomical delimitation of Lavoisiera, Microlicia and Trembleya is problematic. This study aims to fill this gap by identifying leaf characters that are useful for taxonomy of these genera. Species of Rhynchanthera were also included in this study for comparison, since it is an early‐diverging genus of the tribe. Diagnostic characters of Lavoisiera include sessile leaves with spongy parenchyma composed of isodiametric cells, and acute margins with supporting tissue. Trembleya is distinguished by petiolate, microphyllous, and hypostomatic leaves. The presence of depressions on the leaf surface and a homogeneous mesophyll is observed only in species of Microlicia. The leaf characters observed in Rhynchanthera, together with the available phylogenetic studies, were important to indicate evolutionary tendencies in the leaf structure within Microlicieae. Thus, our results indicate a tendency for reduction in leaf size within the tribe, in relation to both the petiole and the lamina. This reduction, which is more pronounced in Microlicia, results in a greater anatomical heterogeneity, due to variations in the organization of both vascular and fundamental tissues. 相似文献
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Different types of pollen cone teratologies in Sequoia sempervirens and Widdringtonia nodiflora were investigated. While wild type pollen cones are uniaxial and hyposporangiate, some teratological polyaxial pollen cones and also perisporangiate microsporangiophores were found. The teratological compound pollen cones in Sequoia seem to represent just random artifacts caused by a spitting of the pollen cone apex, maybe due to a pathogenic event in early developmental stages. In Widdringtonia it remains open, if the compound male reproductive units represent a dense distal cluster of pollen cones or a compound, polyaxial inflorescence comparable to other conifers, e.g. Cephalotaxus (Taxaceae). The perisporangiate microsporangiophores found in some of the teratological pollen cones in Widdringtonia are remarkable, because among extant conifers this type of microsporangiophores is developed only in Taxaceae. Previous studies showed that the perisporangiate type of microsporangiophores represents a radial synangium consisting of several fused hyposporangiate microsporangiophores. However, the perisporangiate microsporangiophores in Taxaceae and Widdringtonia show some distinct structural differences excluding the perisporangiate microsporangiophores in Widdringtonia as representing a radial synangium. 相似文献
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