bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sequence Heterochrony and the Evolution of Development
Authors: Smith Kathleen K. 
Published: August 2002

AbstractOne of the most persistent questions in comparative developmental biology concerns whether there are general rules by which ontogeny and phylogeny are related. Answering this question requires conceptual and analytic approaches that allow biologists to examine a wide range of developmental events in well‐structured phylogenetic contexts. For evolutionary biologists, one of the most dominant approaches to comparative developmental biology has centered around the concept of heterochrony. However, in recent years the focus of studies of heterochrony largely has been limited to one aspect, changes in size and shape. I argue that this focus has restricted the kinds of questions that have been asked about the patterns of developmental change in phylogeny, which has narrowed our ability to address some of the most fundamental questions about development and evolution. Here I contrast the approaches of growth heterochrony with a broader view of heterochrony that concentrates on changes in developmental sequence. I discuss a general approach to sequence heterochrony and summarize newly emerging methods to analyze a variety of kinds of developmental change in explicit phylogenetic contexts. Finally, I summarize a series of studies on the evolution of development in mammals that use these new approaches. J. Morphol. 252:82–97, 2002. © 2002 Wiley‐Liss, Inc.
Evolution of body‐wall musculature in the Platyhelminthes (Acoelomorpha, Catenulida, Rhabditophora)
Authors: Hooge Matthew D. 
Published: August 2002

AbstractIn an effort to understand the phylogeny of the Platyhelminthes, the patterns of body‐wall musculature of flatworms were studied using fluorescence microscopy and Alexa‐488‐labeled phalloidin. Species of the Catenulida have a simple orthogonal gridwork of longitudinal and circular muscles. Members of the Rhabditophora have the same gridwork of musculature, but also have diagonal muscles over their entire body. Although a few species of Acoelomorpha possessed a simple orthogonal grid of musculature, most species typically have distinctly different patterns of dorsal and ventral body‐wall musculature that include sets of longitudinal, circular, U‐shaped, and several kinds of diagonal muscles. Several distinct patterns of musculature were identified, including 8 patterns in 11 families of acoels. These patterns have proven to be useful in clarifying the phylogeny of the Acoelomorpha, particularly with regard to the higher acoels. Patterns of musculature as well as other morphological characters are used here for revisions of acoel systematics, including the return of Eumecynostomum sanguineum (Mecynostomidae) to the genus Aphanostoma (Convolutidae), the revision of the family Childiidae, and the formation of a new family, Actinoposthiidae. J. Morphol. 249:171–194, 2001. © 2001 Wiley‐Liss, Inc.
Ultrastructural evidence for two‐cell and three‐cell neural pathways in the tentacle epidermis of the sea anemone Aiptasia pallida
Authors: Westfall Jane A. , Elliott Carol F. , Carlin Ryan W. 
Published: August 2002

AbstractSensory and ganglion cells in the tentacle epidermis of the sea anemone Aiptasia pallida were traced in serial transmission electron micrographs to their synaptic contacts on other cells. Sensory cell synapses were found on spirocytes, muscle cells, and ganglion cells. Ganglion cells, in turn, synapsed on sensory cells, spirocytes, muscle cells, and other neurons and formed en passant axo‐axonal synapses. Axonal synapses on nematocytes and gland cells were not traced to their cells of origin, i.e., identified sensory or ganglion cells. Direct synaptic contacts of sensory cells with spirocytes and sensory cells with muscle cells suggest a local two‐cell pathway for spirocyst discharge and muscle cell contraction, whereas interjection of a ganglion cell between the sensory and effector cells creates a local three‐cell pathway. The network of ganglion cells and their processes allows for a through‐conduction system that is interconnected by chemical synapses. Although the sea anemone nervous system is more complex than that of Hydra, it has similar two‐cell and three‐cell effector pathways that may function in local responses to tentacle contact with food. J. Morphol. 251:83–92, 2002. © 2002 Wiley‐Liss, Inc.
Fine structure and immunocytochemistry of a new chemosensory system in the chiton larva (Mollusca: Polyplacophora)
Authors: Haszprunar Gerhard , Friedrich Stefan , Wanninger Andreas , Ruthensteiner Bernhard 
Published: August 2002

AbstractCombined electron microscopy and immunocytochemistry of the larvae of several polyplacophoran species (Chiton olivaceus, Lepidochitona aff. corrugata, Mopalia muscosa) revealed a sensory system new to science, a so‐called “ampullary system.” The cells of the “ampullary system” are arranged in four symmetrically situated pairs lying dorsolaterally and ventrolaterally in the pretrochal part of the trochophore‐like larva and they send axons into the cerebral commissure. They are lost at metamorphosis. The fine structure of these cells strongly resembles that of so‐called “ampullary cells” known from various sensory organs of other molluscs, such as the apical complex of gastropod and bivalve larvae, osphradia of vetigastropods, and olfactory organs of cephalopods, and nuchal organs of certain polychaetes. The ampullary cells and their nerves are densely stained by anti‐FMRF‐amide fluorescence dyes, whereas antiserotonin staining is only weak. While cytological homology of the ampullary cells with those of other organs is probable, the ampullary system as a whole is regarded as a synapomorphy of the Polyplacophora or Chitonida. J. Morphol. 251:210–218, 2002. © 2002 Wiley‐Liss, Inc.
Ontogenetic and phylogenetic transformations of the ear ossicles in marsupial mammals
Authors: Sánchez‐Villagra Marcelo R. , Gemballa Sven , Nummela Sirpa , Smith Kathleen K. , Maier Wolfgang 
Published: August 2002

AbstractThis study is based on the examination of histological sections of specimens of different ages and of adult ossicles from macerated skulls representing a wide range of taxa and aims at addressing several issues concerning the evolution of the ear ossicles in marsupials. Three‐dimensional reconstructions of the ear ossicles based on histological series were done for one or more stages of Monodelphis domestica, Caluromys philander, Sminthopsis virginiae, Trichosurus vulpecula, and Macropus rufogriseus. Several common trends were found. Portions of the ossicles that are phylogenetically older develop earlier than portions representing more recent evolutionary inventions (manubrium of the malleus, crus longum of the incus). The onset of endochondral ossification in the taxa in which this was examined followed the sequence; first malleus, then incus, and finally stapes. In M. domestica and C. philander at birth the yet precartilaginous ossicles form a supportive strut between the lower jaw and the braincase. The cartilage of Paauw develops relatively late in comparison with the ear ossicles and in close association to the tendon of the stapedial muscle. A feeble artery traverses the stapedial foramen of the stapes in the youngest stages of M. domestica, C. philander, and Sminthopsis virginiae examined. Presence of a large stapedial foramen is reconstructed in the groundplan of the Didelphidae and of Marsupialia. The stapedial foramen is absent in all adult caenolestids, dasyurids, Myrmecobius, Notoryctes, peramelids, vombatids, and phascolarctids. Pouch young of Perameles sp. and Dasyurus viverrinus show a bicrurate stapes with a sizeable stapedial foramen. Some didelphids examined to date show a double insertion of the Tensor tympani muscle. Some differences exist between M. domestica and C. philander in adult ossicle form, including the relative length of the incudal crus breve and of the stapes. Several differences exist between the malleus of didelphids and that of some phalangeriforms, the latter showing a short neck, absence of the lamina, and a ventrally directed manubrium. Hearing starts in M. domestica at an age in which the external auditory meatus has not yet fully developed, the ossicles are not fully ossified, and the middle ear space is partially filled with loose mesenchyme. The ontogenetic changes in hearing abilities in M. domestica between postnatal days 30 and 40 may be at least partially related to changes in middle ear structures. J. Morphol. 251:219–238, 2002. © 2002 Wiley‐Liss, Inc.
Ultrastructure of the reproductive system of the black swamp snake (seminatrix pygaea). III. Sexual segment of the male kidney
Authors: Sever David M. , Stevens Rebecca A. , Ryan Travis J. , Hamlett William C. 
Published: August 2002

AbstractIn mature male snakes and lizards, a distal portion of the nephron is hypertrophied in relation to its appearance in females and immature males. This sexual segment of the male kidney apparently provides seminal fluid that is mixed with sperm and released into the female cloaca during copulation. In this article, we provide the first study at the ultrastructural level of seasonal variation in the sexual segment of the kidney of a squamate, the natricine snake Seminatrix pygaea. Previous workers have indicated that the sexual segment is secretory only when the testes are spermatogenically active. The sexual segment of the kidney in S. pygaea does not go through an extended period of inactivity but does show a cycle of synthesis and secretion that can be related to the spermatogenic cycle and mating activity. We show that synthesis of secretory product is initiated with the onset of spermatogenic activity in the spring and culminates with completion of spermiation in the fall. Secretion of the product, however, occurs in a premating period in March when the testes are inactive. Secretion during this premating period is probably necessary to provide time for the passage of the products down the ureter in order to mix with sperm during mating later in spring. J. Morphol. 252:238–254, 2002. © 2002 Wiley‐Liss, Inc.
Comparative morphological assessment of the psyllid pleuron (insecta, hemiptera, sternorrhyncha)
Authors: Ouvrard David , Bourgoin Thierry , Campbell Bruce C. 
Published: August 2002

AbstractA unique set of morphological characters based on the hemipteran (sensu lato) thorax are used to define the pleuron of Psylloidea. New external and internal topographical descriptions of pleurites of all three thoracic segments are provided based on observations of specimens from various genera representing the current taxonomic arrangement of Psylloidea. Variations in propleurite morphology and the anteroventral angle of the episternum among taxa are clarified. The mesothoracic pleural sulcus is found to be a distinct groove formed by the deep fossa of the pleural apophysis and is not a secondary structure, as assigned by previous authors. A newly discovered internal apodeme of the metathoracic trochantin and a serially homologous structure in the mesothorax isolate the trochantinal territory of the second segment. The metathoracic pleural sulcus appears to be pressed against the ventral edge of the metepimeron, as previously described for the mesothorax of certain species of other insects having a strongly developed meron. Use of morphological interpretations and newly discovered apodemes to assess primary homology of structures for phylogenetic and taxonomic studies is discussed. A glossary of standardized morphological terms for thoracic structures of non‐heteropteran Hemiptera based on this study and other recent and former dissertations on the insect thorax is provided. J. Morphol. 252:276–290, 2002. © 2002 Wiley‐Liss, Inc.
Functional morphology of the forelimb of Tupaiids (Mammalia, Scandentia) and its phylogenetic implications
Authors: Sargis Eric J. 
Published: August 2002

AbstractIn this study, the forelimb of 12 species of tupaiids was analyzed functionally and compared to that of other archontan mammals. Several differences that relate to differential substrate use were found in the forelimb morphology of tupaiids. These differences included shape of the scapula, length and orientation of the coracoid process, size of the lesser tuberosity, shape of the capitulum, length of the olecranon process, and shape of the radial head and central fossa. The forelimb of the arboreal Ptilocercus lowii, the only ptilocercine, is better adapted for arboreal locomotion, while that of tupaiines is better adapted for terrestrial (or scansorial) locomotion. While the forelimb of the arboreal Ptilocercus appears to be habitually flexed and exhibits more mobility in its joints, a necessity for movement on uneven, discontinuous arboreal supports, all tupaiines are characterized by more extended forelimbs and less mobility in their joints. These restricted joints limit movements more to the parasagittal plane, which increases the efficiency of locomotion on a more even and continuous surface like the ground. Even the most arboreal tupaiines remain similar to their terrestrial relatives in their forelimb morphology, which probably reflects the terrestrial ancestry of Tupaiinae (but not Tupaiidae). The forelimb of Urogale everetti is unique among tupaiines in that it exhibits adaptations for scratch‐digging. Several features of the tupaiid forelimb reflect the arboreal ancestry of Tupaiidae and it is proposed that the ancestral tupaiid was arboreal like Ptilocercus. Also, compared to the forelimb character states of tupaiines, those of Ptilocercus are more similar to those of other archontans and it is proposed that the attributes of the forelimb of Ptilocercus are primitive for the Tupaiidae. Hence, Ptilocercus should be considered in any phylogenetic analysis that includes Scandentia. J. Morphol. 253:10–42, 2002. © 2002 Wiley‐Liss, Inc.
Skull osteology of Parvilacerta parva, a small‐sized lacertid lizard from Asia Minor
Authors: Müller Johannes 
Published: August 2002

AbstractThe skull of the poorly known Asia Minor lacertid lizard Parvilacerta parva is described. In comparison to other palaearctic lacertids, Parvilacerta parva displays several peculiar traits such as a large braincase, a short parietal table, closed post‐temporal openings, reduced ossification, or a large lacrimal. Many features are related to the small size of Parvilacerta parva and are of apparently heterochronic nature, as they can also be found in certain ontogenetic stages of other lacertid species. Small size and heterochrony even seem to be factors involved in the less‐developed sexual dimorphism of Parvilacerta parva. The described morphology is interpreted to be related to a life history strategy in r‐selecting, semiarid environments. J. Morphol. 253:43–50, 2002. © 2002 Wiley‐Liss, Inc.
Focal liver lesions: Comparison of dual‐phase CT and multisequence multiplanar MR imaging including dynamic gadolinium enhancement
Authors: Semelka Richard C. , Martin Diego R. , Balci Cem , Lance Trang 
Published: August 2002

AbstractThe purpose of this study was to compare dual‐phase spiral computed tomography (CT) and magnetic resonance imaging (MRI) using dynamic gadolinium enhancement for liver lesion detection and characterization. Twenty‐two consecutive patients underwent dual‐phase spiral CT and MRI for the evaluation of focal liver disease within a 1‐month period. Spiral CT and MR images were interpreted prospectively, in a blinded fashion by separate, individual, experienced investigators, to determine lesion detection and characterization. Liver lesions were confirmed by surgery and pathology in 6 patients, and by clinical and imaging follow‐up in the other 16 patients. Pathological correlation of a primary extrahepatic malignancy was available in 5 of the 16 patients who had metastatic liver disease. Spiral CT and MRI detected 53 and 63 lesions, and characterized 39 and 62 true positive lesions, respectively. A kappa statistic test was applied to assess agreement between MR and CT results. MR versus CT for lesion detection resulted in a kappa statistic of 0.54 (95% confidence interval), indicating moderate agreement, and 0.32 (95% confidence interval) for lesion characterization, indicating only slight agreement. More lesions were detected on MR images than CT images in 6 (27%) patients, with lesions detected only on MR images in 4 (18%) patients. More lesions were characterized on MR images in 9 (41%) patients. In 9 patients with a discrepancy between MR and CT findings, the MR images added information considered significant to patient management in all 9 cases. MRI was moderately superior to dual‐phase spiral CT for lesion detection, and was markedly superior for lesion characterization, with these differences having clinical significance. J. Magn. Reson. Imaging 2001;13:397–401. © 2001 Wiley‐Liss, Inc.
Identification of adulteration in milk by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Cozzolino R. , Passalacqua S. , Salemi S. , Malvagna P. , Spina E. , Garozzo D. 
Published: August 2002

AbstractThe development is described of a rapid, simply and accurate analytical method aimed at evaluating both the presence of cow milk in either raw ewe and water buffalo milk samples employed in industrial processes and the addition of powdered milk to samples of fresh raw milk, using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). The presence of adulteration is defined by evaluating the protein patterns coming from the most abundant whey proteins, α‐lactalbumin and β‐lactoglobulin, used as molecular markers. As no pretreatment of the milk samples is required and owing to the speed and ease of use of MALDI‐MS the proposed analytical protocol can be used as a routine strategy for the identification of possible adulteration of the raw fresh milk samples that the dairy industry receives from producers every day. Copyright © 2001 John Wiley & Sons, Ltd.
Charge‐reduced nano electrospray ionization combined with differential mobility analysis of peptides, proteins, glycoproteins, noncovalent protein complexes and viruses
Authors: Bacher Gerold , Szymanski Wladyslaw W. , Kaufman Stanley L. , Zöllner Peter , Blaas Dieter , Allmaier Günter 
Published: August 2002

AbstractThis study explores the potential of a novel electrospray‐based method, termed gas‐phase electrophoretic mobility molecular analysis (GEMMA), allowing the molecular mass determination of peptides, proteins and noncovalent biocomplexes up to 2 MDa (dimer of immunglobulin M). The macromolecular ions were formed by nano electrospray ionization (ESI) in the ‘cone jet’ mode. The multiple charged state of the monodisperse droplets/ions generated was reduced by means of bipolar ionized air (generated by an α‐particle source) to yield exclusively singly charged positive and negative ions as well as neutrals. These ions are separated subsequently at atmospheric pressure using a nano differential mobility analyzer according to their electrophoretic mobility in air. Finally, the ions are detected using a standard condensation particle counter. Data were expressed as electrophoretic mobility diameters by applying the Millikan equation. The measured electrophoretic mobility diameters, or Millikan diameters, of 32 well‐defined proteins were plotted against their molecular weights in the range 3.5 to 1920 kDa and exhibited an excellent squared correlation coefficient (r2 = 0.999). This finding allowed the exact molecular weight determination of large (glyco)proteins and noncovalent biocomplexes by means of this new technique with a mass accuracy of ±5.6% up to 2 MDa at the femtomole level. From the molecular masses of the weakly bound, large protein complexes thus obtained, the binding stoichiometry of the intact complex and the complex stability as a function of pH, for example, can be derived. Examples of specific protein complexes, such as the avidin or catalase homo‐tetramer, are used to illustrate the potential of the technique for characterization of high‐mass biospecific complexes. A discussion of current and future applications of charge‐reduced nano ESI GEMMA, such as chemical reaction monitoring (reduction process of immunglobulin G) or size determination of an intact virus, a supramolecular complex, and monitoring of partial dissociation of a human rhinoviruses, is provided. Copyright © 2001 John Wiley & Sons, Ltd.
Symptom pathogenesis during acute influenza: Interleukin‐6 and Other cytokine responses
Authors: Kaiser Laurent , Fritz R. Scott , Straus Stephen E. , Gubareva Larisa , Hayden Frederick G. 
Published: August 2002

AbstractIn experimental human influenza infection initiated by nasal inoculation, the magnitude of viral replication, fever, and symptoms correlate with nasopharyngeal lavage fluid levels of various cytokines. Our aim was to assess these relationships in patients with naturally occurring acute influenza. Patients with culture‐positive influenza illness of less than 36 hr of duration were studied. Nasopharyngeal washing were collected at enrollment and on Day 2, 4, 6 and 8 for quantitative virus isolation and IL‐6, TNF‐α, INF‐α, INF‐γ and IL‐10 determinations. Blood samples collected at entry and on Day 2 and 6 were processed to assess plasma cytokines and circulating influenza RNA. Patients received either oseltamivir or placebo for 5 days. We assessed the correlation between nasopharyngeal lavage fluid or blood levels of cytokines before treatment and viral titers, symptom severity and fever. Sixteen adult subjects (median age of 22 years) were studied. In this small group of patients no significant differences between placebo and oseltamivir patients were found in viral replication or measures of cytokines. Thus the data for all 16 subjects were pooled for analysis. At entry, influenza A viruses were cultured from nasopharyngeal washes at a median titer of 4.8 log10TCID50/ml of wash. Viral titers correlated positively with symptom score (P = 0.006) and temperature values (P < 0.001). Viral titers, fever and symptoms were highest at enrollment and fell in parallel during the subsequent days. RT‐PCR assays failed to detect influenza RNA in the white blood cells from any patient. We observed a significant release, in both nasopharyngeal lavage fluid and in plasma, of IL‐6, TNF‐α, INF‐α, INF‐γ and IL‐10. At entry high IL‐6 levels were detected in the nasopharyngeal lavage fluid (median 10.3 pg/ml) and plasma (median 5.1 pg/ml) of all patients. We found a positive correlation between plasma IL‐6 levels and both symptom scores and temperature values (P < 0.05), as well as a positive correlation between nasopharyngeal lavage fluid levels of IL‐6 and TNF‐α and temperature (P < 0.05). We did not find significant associations between symptoms, fever and levels of INF‐α, INF‐γ or IL‐10. The magnitude of early decrease in viral titers correlated with initial levels of INF‐γ in nasopharyngeal lavage fluid (P < 0.05). Significant production of IL‐6, TNF‐α, INF‐α, INF‐γ and IL‐10 occurs in response to community acquired influenza A illness. As in experimental influenza, symptoms and fever in natural acute influenza correlate with the release of IL‐6. J. Med. Virol. 64:262–268, 2001. © 2001 Wiley‐Liss, Inc.