Respiratory system of arachnids II: morphology of the tracheal system of Leiobunum rotundum and Nemastoma lugubre (Arachnida, Opiliones)

The tracheal system of two species of harvestmen with different life styles was investigated: the long-legged, Leiobunum rotundum (Phalangioidea, Phalangiidae) and the short-legged Nemastoma lugubre (Troguloidea, Nemastomatidae). The morphology of the tracheae is very similar in both species: The branching pattern is basically asymmetric and dichotomous, and the tracheae taper between branching points. The tracheal diameters range from 160 to 0.3 mum in L. rotundum (mean body mass 25.3 mg), and from 70 to 0.5 mum in N. lugubre (mean body mass 3.8 mg). Ultrastructurally, the tracheal walls are similar to those of insects, consisting of an outer hypodermal layer and an inner cuticular layer with taenidial structures. Tracheae of all diameters have close contact with organs and muscles, indicating that diffusive gas exchange may take place through the walls of all tracheae. The finest tracheae end freely in the hemolymph or at the surface of organs and muscles. Exceptions are tracheal penetration of the central nerve mass in the prosoma in both species, and of the muscles in L. rotundum. The latter may correlate with the active perambulatory life style of L. rotundum.     

The developmental patterns of the cartilaginous elements in vertebrate ontogeny]

Comparative embryological data presented in the paper support an idea that chondrification of the mesenchyme does not begin until the latter becomes condensated. Size and density of the skeletogenous rudiments are not the same in different vertebrates. As a rule, in animals with much of the mesenchyme (chondrichthyans, amniotes), the prochondral condensations contain more cells and have both greater mass and density. The distribution pattern of the mesenchyme is also significant for the future development of the cartilaginous elements which at the earlier stages grow largely by the recruitment of surrounding mesenchymal cells. Such kind of the growth mode is probably most similar to the cartilage fusion mode: both processed take place in the absence of the perichondrium. The non-skeletal dense structures influence on the development of the cartilaginous skeleton primarily by determining distribution pattern of the mesenchyme, particularly the condensation of skeletogenous cells. THe growing cartilages themselves can influence mechanically on the surrounding organs.     

Human articular cartilage in relation to age, A morphometric study.

The cell density of the weight-bearing area of normal femoral head cartilage was investigated in 65 cases of both sexes ranging from 6 to 90 years of age. In the maturing cartilage (until about the third decade), the cell density decreases, while in aging cartilage (30-90 years) it remains constant. Our results are in agreement with the main trend of earlier and similar investigations. The reason for contradictory reports is suggested to be due to differences in the selection of criteria for defining 'normal' cartilage. This problem is particularly acute with advancing age, where a great part of the available material shows degenerative changes.     

SEM study on the mucosa of the pre-stomach in Bubalus buffalus

Morpho-structural features of pre-stomach mucosa in the first period of post-natal life in Bubalus buffalus have been studied by SEM. The rumen presents a well defined morpho-structural architecture from 10 to 100 days of life, while in reticulum and in omasum numerous morphological variations have been noticed. During the development, in fact, in these organs the establishment of a typical morphological pattern has been observed.     

太白山太白红杉种群空间分布格局研究

针对研究区太白红杉种群分布特点,设置了15个20 m×20 m样地,采用离散分布理论拟合和聚集强度测定方法,对太白红杉种群空间分布格局进行了比较分析.太白红杉种群空间分布格局属于聚集型,在25m²和100m²面积上聚集强度较大.随海拔上升,聚集强度降低;在分布下限地区,聚集最强的尺度较小,中下部地区较大;阴坡的种群分布聚集强度大于阳坡.随着年龄增加,种群分布由聚集型向随机型过渡,强度减弱;聚集性最强的格局尺度在幼、老龄期为150m²,中龄期则为100m².分布格局受生物学特性、年龄阶段、群落组成、环境因素等影响.在未来保护与利用中,低海拔和阴坡应该适度间伐乔木层非目的树种;在高海拔和阳坡地区,适度间伐灌木,促进群落内团块状更新;育林作业面积应该与聚集性最强的面积相适应.     

Stereological studies of aging changes in epiglottal cartilage cells]

The topic of these investigations were the aging changes of stereological parameters of the cells in human epiglottal cartilage. 42 sagittally cut epiglottides of all ages were available. By means of a drawing mirror in total 8937 cells had been drawn from the slide on paper and then measured. In detail we determined the volume fraction of cartilagous cells in the total cartilage volume, the complete cell surface area of the cartilage, the surface-to-volume ratio of the cartilagous cells, the numerical density of the cells and their volumes. The results are as follows: 1. The volume fraction of cartilagous cells in the total cartilage volume decreases from birth to senium continuously and, with the exception of a more rapid decline during the first decade, linear too. 2. The collective cell surface area per constant test volume of cartilage shows an exponential decline during life. 3. The surface-to-volume ratio of the cartilagous cells decreases very intensively during the first decades, from the 5th decade it little ranges again. 4. In the same way the numerical density of cells intensively decreases up to the 5th decade, but later on it ranges again. 5. The several volumes of cells show from the age of the newborn up to the 40th year a linear steep rise and afterwards, up to senium, an unequivocal decline. 6. The sizes of the cartilagous cells are not normally distributed, on the contrary, in young slides more than in older ones, one size class very predominates.     

Respiratory system of arachnids I: morphology of the respiratory system of Salticus scenicus and Euophrys lanigera (Arachnida, Araneae, Salticidae)

The book-lungs and the tracheal systems of two species of jumping spider, Salticus scenicus and Euophrys lanigera, were investigated using gross anatomical, light and electron microscopic methods. Both species possess well-developed book-lungs of similar size and tracheal systems with a basically similar branching pattern. The tracheal spiracle opens into a single atrium, where it gives rise to four thick 'tube tracheae', from which small secondary tube tracheae originate in groups. The secondary tracheae (diameter 1-5 mum) run parallel, without further branching, into the prosoma. In the opisthosoma, they lie ventrolaterally, where they contact muscles and internal organs. In the prosoma, the secondary tracheae may penetrate the gut epithelium and central nervous tissue. The structure of the tracheal walls is very similar to that of insects, consisting of a striated inner cuticular layer with taenidial structures and a surrounding outer hypodermal layer. The wall thickness appears similar in all secondary tracheae, indicating that lateral gas diffusion may be possible through the walls of all small tube tracheae.     

Immunohistochemical demonstration of -(carboxymethyl)lysine protein adducts in normal and osteoarthritic cartilage

N(epsilon)-(carboxymethyl)lysine (CML) is an advanced glycation end product formed by non-enzymatic glycation and oxidation of proteins. The distribution pattern of CML-modified proteins in normal and osteoarthritic (OA) cartilage was investigated using specific antibodies. In healthy articular cartilage, immunoreactivity for CML was preferably found in the extracellular matrix (ECM) of the superficial layer. In OA samples, CML immunoreactivity was not restricted to the ECM of the superficial layer. Interestingly, OA chondrocytes showed a remarkable cytoplasmic immunoreactivity for CML. With the help of a western blot analysis CML-modified proteins between 68 and 39 kDa could be demonstrated in OA cartilage samples. These results suggest that the accumulation of CML adducts contributes to the matrix damage in osteoarthritis. Therefore, the inhibition of CML accumulation may represent an effective therapeutic strategy to prevent severe OA cartilage injury.     

The tracheal system of the developing primary olfactory pathway of Manduca sexta: tracheae do not play a guidance or targeting role for ingrowing receptor axons

Axons navigate to their targets by detecting signals within the environment through which they are growing. The surfaces of tracheae, which are prominent features of the insect body plan, could be detected as favorable pathways for sensory axons growing toward the brain. The pattern of the tracheal investment of the adult antennal lobe of the moth Manduca sexta suggested two specific possibilities for interaction between tracheae and axons during development: that tracheae might be involved in guiding olfactory receptor axons to their target region of the brain, the antennal lobe; and that tracheae could provide an address system within the lobe that defines the sites of glomeruli, which are olfactory-axon target areas within the lobe. To determine whether tracheae contribute to development of the primary olfactory pathway, the distribution of tracheae in the adult and developing antennal lobes was examined with both confocal and electron microscopes. During the major stages in which axons are growing into the antennal lobe and in which glomeruli are forming, the tracheal investment of the nerve and lobe was found to be minimal. Tracheae thus cannot serve as axon guides or as local address sites for newly forming glomeruli during the initial targeting of receptors onto the antennal lobe.     

The ears of butterflyfishes (Chaetodontidae): ‘hearing generalists' on noisy coral reefs?

Analysis of the morphology of all three otolithic organs (sacculus, lagena and utriculus), including macula shape, hair cell morphology, density, orientation pattern, otolith morphology and the spatial relationships of the swimbladder and ear, reveals that butterflyfishes in the genera Chaetodon (which has anterior swimbladder horns) and Forcipiger (which lacks anterior swimbladder horns) both demonstrate the ear morphology typical of teleosts that lack otophysic connections, fishes that have traditionally been considered to be 'hearing generalists'.     

The distribution of serum albumin in human normal and degenerate articular cartilage

A method for studying the distribution of a high molecular weight solute (serum albumin) between physiological saline and human articular cartilage is described. Samples of normal and fibrillated articular cartilage from both femoral condyles and femoral heads have been studied. Limited studies have also been performed where the glycosaminoglycan content of normal cartilage has been reduced by chemical or enzymatic methods. With naturally occuring cartilage large a wide range of partition coefficients (0.3 to less than 0.002) was obtained. The partition coefficients are very dependent upon proteoglycan concentration, with the partitiion coefficient decreasing with increasing fixed charge density. An attempt is made to interpret the observed partitioning in terms of the steric exclusion by the proteoglycans.     

The distribution of serum albumin in human normal and degenerate articular cartilage.

A method for studying the distribution of a high molecular weight solute (serum albumin) between physiological saline and human articular cartilage is described. Samples of normal and fibrillated articular cartilage from both femoral condyles and femoral heads have been studied. Limited studies have also been performed where the glycosaminoglycan content of normal cartilage has been reduced by chemical or enzymic methods. With naturally occurring cartilage a wide range of partition coefficients (0.3 to less than 0.002) was obtained. The partition coefficients are very dependent upon proteoglycan concentration, with the partition coefficient decreasing with increasing fixed charge density. An attempt is made to interpret the observed partitioning in terms of the steric exclusion by the proteoglycans.     

典型喀斯特小流域土壤有机碳和全氮空间格局变化及其对退耕还林还草的响应

基于定点回顾实验设计,通过对比分析2005年初(退耕还林还草初期)和2014年底典型喀斯特峰丛洼地小流域土壤碳氮格局变化,探讨石漠化治理工程实施后,植被恢复对土壤碳氮积累和碳氮空间格局的影响。研究结果发现:退耕还林还草10a后,示范区土壤有机碳(SOC)含量显著增加1.3g/kg,但土壤全氮含量无显著变化;就空间格局而言,退耕还林还草初期土壤碳氮高值聚类区主要分布在坡脚旱地和荒地(荒草)类型区,退耕还林还草10a后其高值聚类区主要分布在荒地(灌丛和荒草)类型区,而10a前后土壤碳氮的低值聚类区始终分布在洼地旱地类型区;2005年和2014年土壤有机碳半变异函数的拟合模型相同,均为球状模型,在退耕还林还草10a后空间异质性增强,土壤有机碳的空间格局受土壤母质和植被结构的影响增强;而土壤全氮半变异函数的拟合模型不同,由指数模型变为球状模型,在退耕还林还草10a后空间异质性减弱,土壤全氮的空间格局受随机因素影响增强。研究结果对石漠化区域土地利用结构的优化调整具有重要的科学参考和实践指导意义。     

Ontogeny of tracheal dimensions and gas exchange capacities in the grasshopper, Schistocerca americana

How does body size affect the structure and gas exchange capacities of insect tracheae? Do insects become more oxygen-limited as they grow? We addressed these questions by measuring the dimensions of two transverse tracheae within the abdomen of American locusts of different ages, and evaluating the potential for diffusion or convection to provide adequate gas exchange. The grasshopper abdomen has longitudinal tracheae that run along the midgut, heart, nerve cord, and lateral body wall. Transverse tracheae run from each spiracle to the longitudinal tracheae. Dorsal air sacs attach near each spiracle. In both transverse tracheae studied, diffusive capacities increased more slowly than metabolic rates with age, and calculated oxygen gradients necessary to supply oxygen by diffusion increased exponentially with age. However, surgical studies demonstrated that transport of gas through these transverse tracheae occurred by convection, at least in adults. Convective capacities paralleled metabolic rates with age, and the calculated pressure gradients required to sustain oxygen consumption rates by convection were independent of age. Thus, in growing grasshoppers, tracheal capacities matched tissue oxygen needs. Our morphological and physiological data together suggest that use of convection allows older grasshoppers to overcome potential limitations on size imposed by diffusion through tracheal systems.     

Ontogeny of tracheal dimensions and gas exchange capacities in the grasshopper, Schistocerca americana

How does body size affect the structure and gas exchange capacities of insect tracheae? Do insects become more oxygen-limited as they grow? We addressed these questions by measuring the dimensions of two transverse tracheae within the abdomen of American locusts of different ages, and evaluating the potential for diffusion or convection to provide adequate gas exchange. The grasshopper abdomen has longitudinal tracheae that run along the midgut, heart, nerve cord, and lateral body wall. Transverse tracheae run from each spiracle to the longitudinal tracheae. Dorsal air sacs attach near each spiracle. In both transverse tracheae studied, diffusive capacities increased more slowly than metabolic rates with age, and calculated oxygen gradients necessary to supply oxygen by diffusion increased exponentially with age. However, surgical studies demonstrated that transport of gas through these transverse tracheae occurred by convection, at least in adults. Convective capacities paralleled metabolic rates with age, and the calculated pressure gradients required to sustain oxygen consumption rates by convection were independent of age. Thus, in growing grasshoppers, tracheal capacities matched tissue oxygen needs. Our morphological and physiological data together suggest that use of convection allows older grasshoppers to overcome potential limitations on size imposed by diffusion through tracheal systems.     

Nuclear pore clustering is a consistent feature of apoptosis in vitro

Two cell lines which show different patterns of DNA fragmentation have been examined for variations of their nuclear morphology during apoptosis. FDCP-Mix, a pluripotent murine haemopoietic stem cell line which undergoes typical internucleosomal cleavage of DNA when induced to apoptosis either by drugs or withdrawal of growth factor (IL-3) was compared with the human lymphoid leukemia cell line MOLT-4, a cell line which undergoes apoptosis without production of a typical DNA 'ladder'. The nuclear morphology of FDCP-Mix cells was consistent after apoptotic induction by drug or by growth factor withdrawal. Apoptotic nuclear morphology for MOLT-4 and FDCP-Mix showed variations in the distribution, density and texture of the electron dense nuclear marginations. Despite these differences, clustering of nuclear pore complexes (NPCs) after treatment with the topoisomerase II inhibitor etoposide was a common phenomenon for both cell lines. Moreover, pore clustering for FDCP-Mix nuclei occurred independently from the way in which apoptosis was induced, either by growth factor withdrawal or etoposide treatment. In a novel approach, we visualised the clustering of NPCs three-dimensionally by field emission in-lens scanning electron microscopy (FEISEM).     

Mass spectrometry image correlation: quantifying colocalization

A typical imaging mass spectrometry data set can contain 100+ images, each describing the distribution of a specific biomolecule. Multivariate and hierarchical clustering techniques have been developed to investigate the correlations within a data set, and have revealed the differential patterns associated with different organs/anatomical features. These methods do not quantify the correlations between the hundreds of molecular distributions produced in an imaging mass spectrometry experiment, and are extremely difficult to apply to multiple tissue section investigations. This latter aspect includes quantifying the correlation between the results of repeat imaging mass spectrometry experiments, a crucial aspect for determining the significance of any measured changes in distribution. To date, the large chemical background and pixel-to-pixel variation in the images has limited the quantification of correlation between imaging mass spectrometry results. Here, we demonstrate how to quantify the correlations between imaging mass spectrometry images, both within a data set and between data sets.     

Association of tracheal placodes with leg primordia in Drosophila and implications for the origin of insect tracheal systems

Adaptation to diverse habitats has prompted the development of distinct organs in different animals to better exploit their living conditions. This is the case for the respiratory organs of arthropods, ranging from tracheae in terrestrial insects to gills in aquatic crustaceans. Although Drosophila tracheal development has been studied extensively, the origin of the tracheal system has been a long-standing mystery. Here, we show that tracheal placodes and leg primordia arise from a common pool of cells in Drosophila, with differences in their fate controlled by the activation state of the wingless signalling pathway. We have also been able to elucidate early events that trigger leg specification and to show that cryptic appendage primordia are associated with the tracheal placodes even in abdominal segments. The association between tracheal and appendage primordia in Drosophila is reminiscent of the association between gills and appendages in crustaceans. This similarity is strengthened by the finding that homologues of tracheal inducer genes are specifically expressed in the gills of crustaceans. We conclude that crustacean gills and insect tracheae share a number of features that raise the possibility of an evolutionary relationship between these structures. We propose an evolutionary scenario that accommodates the available data.     

Adherence of Bordetella bronchiseptica 276 to porcine trachea maintained in organ culture

Two organ culture models have been adapted for porcine tracheae in order to study colonization by Bordetella bronchiseptica. Rings or segments excised from tracheae of newborn piglets were incubated overnight at 37 degrees C in a nutrient medium under 5% CO2-95% air conditions. Tracheal segments were infected with B bronchiseptica 276, and after different incubation times, bacterial counts were done. B. bronchiseptica adhered well to tracheae maintained in culture, and no statistically significant differences between the two models were observed. Noninfected tracheal mucosae maintained a normal appearance for several days, whereas infected mucosae showed typical damage caused by B. bronchiseptica, namely, loss of ciliary activity and cilia and sloughing of ciliated cells. Our data indicated that porcine tracheal organ culture could be advantageously used to study in vitro colonization by B. bronchiseptica.