bluuebunny/crossref_metadata_2025_split huggingface dataset:
A review of morphological techniques for detection of peroxisomal (and mitochondrial) proteins and their corresponding mRNAs during ontogenesis in mice: Application to the PEX5‐knockout mouse with Zellweger syndrome
Authors: Baumgart Eveline , Fahimi H. Dariush , Steininger Heike , Grabenbauer Markus 
Published: May 2003

AbstractIn the era of application of molecular biological gene‐targeting technology for the generation of knockout mouse models to study human genetic diseases, the availability of highly sensitive and reliable methods for the morphological characterization of the specific phenotypes of these mice is of great importance. In the first part of this report, the role of morphological techniques for studying the biology and pathology of peroxisomes is reviewed, and the techniques established in our laboratories for the localization of peroxisomal proteins and corresponding mRNAs in fetal and newborn mice are presented and discussed in the context of the international literature. In the second part, the literature on the ontogenetic development of the peroxisomal compartment in mice, with special emphasis on liver and intestine is reviewed and compared with our own data reported recently. In addition, some recent data on the pathological alterations in the liver of the PEX5−/− mouse with a peroxisomal biogenesis defect are briefly discussed. Finally, the methods developed during these studies for the localization of mitochondrial proteins (respiratory chain complexes and MnSOD) are presented and their advantages and pitfalls discussed. With the help of these techniques, it is now possible to identify and distinguish unequivocally peroxisomes from mitochondria, two classes of cell organelles giving by light microscopy a punctate staining pattern in microscopical immunohistochemical preparations of paraffin‐embedded mouse tissues. Microsc. Res. Tech. 61:121–138, 2003. © 2003 Wiley‐Liss, Inc.
Peroxisome assembly in yeast
Authors: Veenhuis Marten , Kiel Jan A.K.W. , Van der Klei Ida J. 
Published: May 2003

AbstractPeroxisomes are essential organelles that may be involved in various functions, dependent on organism, cell type, developmental stage of the cell, and the environment. Until recently, peroxisomes were viewed as a class of static organelles that developed by growth and fission from pre‐existing organelles. Recent observations have challenged this view by providing evidence that peroxisomes may be part of the endomembrane system and constitute a highly dynamic population of organelles that arises and is removed upon environmental demands. Additionally, evidence is now accumulating that peroxisomes may arise by alternative methods. This review summarizes relevant recent data on this subject. In addition, the progress in the understanding of the principles of the peroxisomal matrix protein import machinery is discussed. Microsc. Res. Tech. 61:139–150, 2003. © 2003 Wiley‐Liss, Inc.
Degradation of normal and proliferated peroxisomes in rat hepatocytes: Regulation of peroxisomes quantity in cells
Authors: Yokota Sadaki 
Published: May 2003

AbstractDegradation and turnover of peroxisomes is reviewed. First, we describe the historical aspects of peroxisome degradation research and the two major concepts for breakdown of peroxisomes, i.e., autophagy and autolysis. Next, the comprehensive knowledge on autophagy of peroxisomes in mammalian and yeast cells is reviewed. It has been shown that proliferated peroxisomes are degraded by selective autophagy, and studies using yeast cells have been especially helpful in shedding light on the molecular mechanisms of this process. The degradation of extraperoxisomal urate oxidase crystalloid is noted. Overexpressed wild‐type urate oxidase in cultured cells has been shown to be degraded through an unknown proteolytic pathway distinct from the lysosomal system including autophagy or the ubiquitin‐proteasome system. Finally, peroxisome autolysis mediated by 15‐lipoxygenase (15‐LOX) is described. 15‐LOX is integrated into the peroxisome membrane causing focal membrane disruptions. The content of the peroxisomes is then exposed to cytosol proteases and seems to be digested quickly. In conclusion, the number of peroxisomes appears to be regulated by two selective pathways, autophagy, including macro‐ and microautophagy, and 15‐LOX‐mediated autolysis. Microsc. Res. Tech. 61:151–160, 2003. © 2003 Wiley‐Liss, Inc.
Selective degradation of peroxisomes in yeasts
Authors: Bellu Anna Rita , Kiel Jan A.K.W. 
Published: May 2003

AbstractIn the last two decades, much progress has been made in understanding the process of induction and biogenesis of peroxisomes, essential organelles in all eukaryotes. Only relatively recently, the first molecular studies on the selective degradation of this important organelle—a process known as pexophagy, which occurs when the organelles have become redundant—have been performed, especially using methylotrophic yeasts. The finding that pexophagy and other transport pathways to the vacuole (vacuolar protein sorting, autophagy, cytoplasm‐to‐vacuole‐targeting and endocytosis) utilize common but also unique genes has placed pexophagy in the heart of the machinery that recycles cellular material. The quest is now on to understand how peroxisome degradation has become such a highly selective process and what the signals are that trigger it. In addition, because the prime determinant of pexophagy is located on the peroxisome itself, it has become essential to study the role of peroxisomal membrane proteins in the degradation process in detail. This review highlights the main achievements of the last years. Microsc. Res. Tech. 61:161–170, 2003. © 2003 Wiley‐Liss, Inc.
Peroxisomal motility and interaction with microtubules
Authors: Schrader Michael , Thiemann Meinolf , Fahimi H. Dariush 
Published: May 2003

AbstractRecent in vivo observations have revealed that peroxisomes are more dynamic and interactive than previously assumed. The growing recognition of the tubular and reticular morphology of peroxisomes in living cells, their association with microtubules, and the dynamic movements of peroxisomes in vivo and in vitro have inspired the query into the investigation of the cellular machinery that mediates such a complex behaviour. The characterisation of the underlying molecular components of this machinery is providing insight into the mechanisms regulating peroxisomal morphology and intracellular distribution. Microsc. Res. Tech. 61:171–178, 2003. © 2003 Wiley‐Liss, Inc.
Regulation of cell proliferation and cell death by peroxisome proliferators
Authors: Cattley Russell C. 
Published: May 2003

AbstractPeroxisome proliferators cause increases in liver mass in rodents, linked to changes in cell proliferation and cell death of hepatocytes. These effects are reversible upon cessation of treatment. The underlying mechanism of the response in rodent liver is complex, but clearly dependent on activation of the nuclear receptor PPARα. Other signaling pathways have been implicated in this response, but evidence is mixed. Differing sensitivity among various species to effects of peroxisome proliferators has been associated with differences in PPARα expression and function. Changes in cell proliferation and cell death in neoplastic hepatocytes also have been found in liver tumors caused by long‐term treatment with peroxisome proliferators. Microsc. Res. Tech. 61:179–184, 2003. © 2003 Wiley‐Liss, Inc.
Induction of the expression of the peroxisome proliferator‐activated receptor alpha (PPARα) by clofibrate in jerboa tissues
Authors: Amsaguine‐Safir Siham , Bianchi Arnaud , Collet Philippe , Huin‐Schohn Cécile , Jeanvoine Adeline , Bécuwe Philippe , Krémarik‐Bouillaud Pascaline , Domenjoud Lionel , Keller Jean Marie , Schohn Hervé , Dauça Michel 
Published: May 2003

AbstractPeroxisome proliferator‐activated receptor alpha (PPARα) is a member of the nuclear hormone receptor superfamily that can be activated by natural fatty acids and various xenobiotics, including clofibrate. This transcription factor primarily regulates genes involved in lipid metabolism and homeostasis. We present the expression pattern of the PPARα subtype in the adult jerboa Jaculus orientalis, determined by RT‐PCR and Western blotting using specific probes and a polyclonal antibody for PPARα, respectively. PPARα is highly expressed in liver and kidney, and to a lesser extent in duodenum and colon. PPARα expression is increased at the mRNA and protein levels in liver and duodenum of jerboa treated for 2 weeks with the peroxisome proliferator (PP) clofibrate. The induction is tissue‐specific as no significant changes are observed in kidney and colon. The present data indicate that the PP‐induced PPARα gene expression is not dependent on the PPARα content in target cells. Microsc. Res. Tech. 61:185–190, 2003. © 2003 Wiley‐Liss, Inc.
Peroxisome proliferation as a biomarker in environmental pollution assessment
Authors: Cajaraville Miren P. , Cancio Ibon , Ibabe Arantza , Orbea Amaia 
Published: May 2003

AbstractPeroxisome proliferators comprise a heterogeneous group of compounds known for their ability to cause massive proliferation of peroxisomes and liver carcinogenesis in rodents. In recent years it has become evident that other animals may be threatened by peroxisome proliferators, in particular aquatic organisms living in coastal and estuarine areas. These animals are exposed to a variety of pollutants of industrial, agricultural and urban origin which are potential peroxisome proliferators. Both laboratory and field studies have shown that phthalate ester plasticizers, PAHs and oil derivatives, PCBs, certain pesticides, bleached kraft pulp and paper mill effluents, alkylphenols and estrogens provoke peroxisome proliferation in different fish or bivalve mollusc species. The response appears to be mediated by peroxisome‐proliferator activated receptors, members of the nuclear receptor family, recently cloned in fish. Based on these results it is proposed that peroxisome proliferation could be used as a biomarker of exposure to a variety of pollutants in environmental pollution assessment. This is illustrated by a case study in which mussels, used worldwide as sentinels of environmental pollution, were transplanted from reference to contaminated areas and vice versa. In mussels native to an area polluted with PAHs and PCBs, peroxisomal acyl‐CoA oxidase (AOX) activity and peroxisomal volume density were 2‐3 fold and 5‐fold higher, respectively, compared to the reference site. When animals were transplanted to the polluted station, with increased concentration of organic xenobiotics, a concomitant significant increase of AOX was recorded. Conversely, in animals transplanted to the cleaner station, AOX activity and peroxisomal volume density decreased significantly. These results indicate that peroxisome proliferation is a rapid (i.e., two days) and reversible response to pollution in mussels. Before peroxisome proliferation can be implemented as a biomarker in biomonitoring programs, a well‐defined protocol should be established and validated in intercalibration and quality assurance programmes. Furthermore, the influence of biotic and abiotic factors, some of which are known to affect peroxisome proliferation (season, tide level, interpopulation and interindividual variability), should be taken into consideration. The possible hepatocarcinogenic effects as well as the potential adverse effects on reproduction, development, and growth of peroxisome proliferators are unknown in aquatic organisms, thus providing a challenge for future investigations. Microsc. Res. Tech. 61:191–202, 2003. © 2003 Wiley‐Liss, Inc.
Human peroxisomal disorders
Authors: Depreter Marianne , Espeel Marc , Roels Frank 
Published: May 2003

AbstractPeroxisomes are single membrane‐bound cell organelles performing numerous metabolic functions. The present article aims to give an overview of our current knowledge about inherited peroxisomal disorders in which these organelles are lacking or one or more of their functions are impaired. They are multiorgan disorders and the nervous system is implicated in most. After a summary of the historical names and categories, each having distinct symptoms and prognosis, microscopic pathology is reviewed in detail. Data from the literature are added to experience in the authors' laboratory with 167 liver biopsy and autopsy samples from peroxisomal patients, and with a smaller number of chorion samples for prenatal diagnosis, adrenal‐, kidney‐, and brain samples. Various light and electron microscopic methods are used including enzyme‐ and immunocytochemistry, polarizing microscopy, and morphometry. Together with other laboratory investigations and clinical data, this approach continues to contribute to the diagnosis and further characterization of peroxisomal disorders, and the discovery of novel variants. When liver specimens are examined, three main groups including 9 novel variants (33 patients) are distinguished: (1) absence or (2) presence of peroxisomes, and (3) mosaic distribution of cells with and without peroxisomes (10 patients). Renal microcysts, polarizing trilamellar inclusions, and insoluble lipid in macrophages in liver, adrenal cortex, brain, and in interstitial cells of kidney are also valuable for classification. On a genetic basis, complementation of fibroblasts has classified peroxisome biogenesis disorders into 12 complementation groups. Peroxisome biogenesis genes (PEX), knock‐out‐mice, and induction of redundant genes are briefly reviewed, including some recent results with 4‐phenylbutyrate. Finally, regulation of peroxisome expression during development and in cell cultures, and by physiological factors is discussed. Microsc. Res. Tech. 61:203–223, 2003. © 2003 Wiley‐Liss, Inc.
Statistical estimators of frontal sinus cross section ontogeny from very noisy data
Authors: Prossinger Hermann , Bookstein Fred L. 
Published: May 2003

AbstractCross‐sectional areas of human frontal sinuses in the occipitofrontal projection are a good surrogate for frontal sinus volumes. This study looks at these areas in a dataset of some 200 children and 100 adults of both sexes. As measured by planimetry of roentgenograms, the areas are extremely variable (“noisy” in a statistical sense). In fact, they appear to be distributed log‐normally with quite high variance. The mean of the distribution is evidently a function of age and the variances differ by sex. After logarithmic transformation, the data are adequately fitted by one sigmoid curve for each sex. Our discussion highlights implications of this finding for the biological aspects of frontal sinuses and methodological issues in ontogenetic analysis of data so noisy. J. Morphol. 257:1–8, 2003. © 2003 Wiley‐Liss, Inc.
Sperm ultrastructure in the nudibranch genus Halgerda with reference to other discodorididae and to chromodorididae (mollusca: Opisthobranchia)
Authors: Fahey Shireen J. , Healy John M. 
Published: May 2003

AbstractComparative sperm ultrastructure within the molluscan nudibranch genus Halgerda (Discodorididae) was examined for the first time using transmission electron microscopy (TEM), based on 17 of the 35 known species. In addition, observations on two other discodorids are made to facilitate outgroup comparison with Halgerda, including one species of Discodoris (D. boholiensis) and Asteronotus cespitosus (currently accepted as the closest sister taxon to Halgerda). Comparison was also made with some genera of the Chromodorididae in view of sperm similarities. Spermatozoa of all species examined were of the complex, helical, elongate (∼300–400 μm) type characteristic of most heterobranch gastropods. These cells exhibit the following discrete regions (in anteroposterior sequence) : an acrosomal complex (composed of a rounded, membrane‐bound vesicle and a column‐like pedestal); a solid, helical nucleus; an elongate, helical midpiece (composed of an axoneme and associated nine coarse fibers, an enveloping mitochondrial derivative of matrix, and paracrystalline materials and glycogen helix); an annular complex; and a short glycogen piece. Of these regions, the midpiece is by far the longest, occupying over 90% of the total sperm length. Comparison with other members of the radula‐bearing cryptobranch dorids reveals several sperm similarities to other genera in the clade, particularly those of other Discodorididae and also with the Chromodorididae. Comparison with previously studied genera reveals noteworthy sperm differences within the Discodorididae. The most notable differences are the internal structure of the acrosomal pedestal (long and homogeneous in Halgerda, Discodoris; short and homogeneous in Asteronotus; long and finely striated in Rostanga; oblong with angular electron‐lucent striations in Jorunna) and the internal structure of the glycogen piece. The pronounced helical keels of most Halgerda and Discodoris nuclei contrast with the weakly helical nucleus of Asteronotus. Sperm features alone do not provide a means of defining the genus Halgerda or the family Discodorididae nor do they support the monophyletic status of the caryophyllidia‐bearing dorids. Important sperm characters such as the acrosome, nucleus, and midpiece can often still be determined from specimens that have been initially fixed in formalin, then stored in ethanol for extended periods of time (i.e., museum material). Of all sperm features, the mitochondrial derivative of the midpiece is the most resistant to long‐term fixation : the survival of acrosomal, nuclear, and axonemal components is variable, presumably a factor of prefixation autolysis, varied primary fixation times and temperatures, formalin quality, and duration of alcohol storage. J. Morphol. 257:9–21, 2003. © 2003 Wiley‐Liss, Inc.
Winged presoldiers induced by a juvenile hormone analog in Zootermopsis nevadensis: Implications for plasticity and evolution of caste differentiation in termites
Authors: Miura Toru , Koshikawa Shigeyuki , Matsumoto Tadao 
Published: May 2003

AbstractTo elucidate the switching mechanism of caste differentiation in termites and to examine the possible induction of soldier‐reproductive intercastes experimentally, we investigated the effects of juvenile hormone on the morphologies of soldier caste by applying a juvenile hormone analog (JHA) to nymphs of the damp‐wood termite Zootermopsis nevadensis (Isoptera : Termopsidae). JHA treatment for about 2 weeks induced a variety of intermediate castes, showing both alate and soldier morphological features. The principal component analysis (PCA) of those morphological characters showed that those intercastes were a deviation from the developmental line into alates to soldier differentiation, which is known to be triggered by juvenile hormone. Detailed morphological examination of the compound eyes, wing joint, and mandibles showed that those intercastes expressed soldier features, although they had started to develop alate characteristics. The morphology of the resultant intercastes seemed to be determined by the nymphal stage, at which JHA treatment was applied. The induced intercastes with exaggerated soldier‐specific characteristics (e.g., mandibles) repressed alate‐specific characteristics (e.g., wings), namely, the alate and soldier morphological characteristics in induced intercastes show opposite responses against the application of JHA. On the other hand, ovarian development was not suppressed by the JHA application, even in the soldier‐like individuals. Naturally differentiated presoldiers also possessed developed ovarioles, although ovaries of mature soldiers were degenerated. Our results suggest that the juvenile hormone plays complicated roles in the expression of caste morphologies and ovarian development in termites. J. Morphol. 257:22–32, 2003. © 2003 Wiley‐Liss, Inc.
Interspecific variations in the morphology and ultrastructure of the rhabdoms of Oplophorid shrimps
Authors: Gaten Edward , Shelton Peter M.J. , Nowel Mark S. 
Published: May 2003

AbstractInterspecific variations in rhabdom structure between various oplophorid shrimps are described and the differences are related to the light environment at different depths within the mesopelagic zone. The ultrastructure of the distal rhabdom in these species is described for the first time. Quantitative measurements show that the proportion of the rhabdom layer occupied by the distal rhabdom varies from 3.5–25% in the dorsoventral plane of the eye of Systellaspis debilis. The distal rhabdom occupies less than 1% of the rhabdoms in the eye of Acanthephyra pelagica, where it can only be seen by using the electron microscope. It is suggested that the rhabdoms of those species that remain within the photic zone (such as S. debilis) are adapted to maximize contrast, whereas in those whose depth ranges extend into the aphotic zone (such as A. pelagica) they are adapted for maximum sensitivity. J. Morphol. 257:87–95, 2003. © 2003 Wiley‐Liss, Inc.
Biomechanics of the rostrum and the role of facial sutures
Authors: Rafferty Katherine L. , Herring Susan W. , Marshall Christopher D. 
Published: May 2003

AbstractThe rostrum is a large diameter, thin‐walled tubular structure that receives loads from the teeth. The rostrum can be conceptualized both as a rigid structure and as an assemblage of several bones that interface at sutures. Using miniature pigs, we measured in vivo strains in rostral bones and sutures to gain a better understanding of how the rostrum behaves biomechanically. Strains in the premaxillary and nasal bones were low but the adjacent maxillary‐premaxillary, internasal, and intermaxillary suture strains were larger by an order of magnitude. While this finding emphasizes the composite nature of the rostrum, we also found evidence in the maxillary and nasal bones for rigid structural behavior. Namely, maxillary strain is consistent with a short beam model under shear deformation from molar loading. Strain in the nasal bones is only partially supported by a long beam model; rather, a complex pattern of dorsal bending of the rostrum from incisor contact and lateral compression is suggested. Torsion of the maxilla is ruled out due to the bilateral occlusion of pigs and the similar working and balancing side strains, although it may be important in mammals with a unilateral bite. Torsional loading does appear important in the premaxillae, which demonstrate working and balancing side changes in strain orientation. These differences are attributed to asymmetrical incisor contact occurring at the end of the power stroke. J. Morphol. 257:33–44, 2003. © 2003 Wiley‐Liss, Inc.