bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lateral magnocellular nucleus of the anterior neostriatum (LMAN) in the zebra finch: Neuronal connectivity and the emergence of sex differences in cell morphology
Authors: Nixdorf‐Bergweiler Barbara E. 
Published: August 2002

AbstractThe song system of birds provides a model system to study basic mechanisms of neuronal plasticity and development underlying learned behavior. Song learning and production involve discrete sets of interconnected nuclei in the avian brain. One of these nuclei, the lateral magnocellular nucleus of the anterior neostriatum (LMAN), is the output of the so‐called anterior forebrain pathway known to be essential for learning and maintenance of song, both processes depending on auditory feedback. In zebra finches, only males sing and this sexually dimorphic behavior is mirrored by sexual dimorphism in neuronal structure that develops during ontogeny. Female zebra finches are not able to sing and nuclei of the song system are strongly reduced in size or even lacking, when compared to male brains. Only LMAN can be delineated as easily in females as in males. Since female zebra finches, despite being unable to sing, recognize song just as males do and form a memory for song (model acquisition) early in life, LMAN is a putative candidate for song acquisition in both sexes. Therefore, development of LMAN was studied at the cellular and ultrastructural level in both male and female zebra finches. Regressive development of dendritic spines, enlargement of neuronal cell body and nuclei size, as well as changes at the nucleolar level are events all occurring exclusively in males, when song learning progresses. The decline in synapse number and the augmentation in synaptic contact length at synapses in LMAN in males are indicative for synaptic plasticity, whereas in females synapse number and synaptic contact length remain unchanged. Microsc. Res. Tech. 54:335–353, 2001. © 2001 Wiley‐Liss, Inc.
Molecular sexing of monomorphic endangered Ara birds
Authors: Bermúdez‐Humarán Luis Gilberto , García‐García Aracely , Leal‐Garza Carlos Humberto , Riojas‐Valdes Victor Manuel , Jaramillo‐Rangel Gilberto , Montes‐de‐Oca‐Luna Roberto 
Published: August 2002

AbstractSurvival of most endangered birds may depend on breeding programs where sex identification plays an important role. Molecular sexing has shown to be a rapid and safe procedure. In this work we established sex identification of monomorphic endangered Ara birds using a chromosome W‐linked DNA marker, the Chromo‐helicase‐DNA‐Binding 1 (CHD) gene. Most birds have two CHD sex‐linked genes, one W‐linked (CHD‐W) and one Z‐linked (CHD‐Z). These markers were characterized from Ara militaris and gender sex was determined by PCR and restriction analyzes. The procedure here reported was successfully applied to five different species of the genus Ara and confirmed the validity of the technique. To our knowledge, this is the first report of molecular sexing of the Ara species. This molecular sexing is currently been used in breeding programs of Ara birds. J. Exp. Zool. 292:677–680, 2002. © 2002 Wiley‐Liss, Inc.
Metamorphosis of summer flounder, Paralichthys dentatus: Cell proliferation and differentiation of the gastric mucosa and developmental effects of altered thyroidal status
Authors: Soffientino Bruno , Specker Jennifer L. 
Published: August 2002

AbstractSummer flounder, like most marine fishes studied to date, are stomachless at first feeding, and subsequently acquire gastric function during the process of metamorphosis. Stomach formation is controlled largely by thyroxine (T4). In the present work we sought to understand gastric organogenesis in terms of cell proliferation and its relationship to histological differentiation. The objectives of the study were (1) to obtain a developmental pattern of cell proliferation in the gastric mucosa and to relate that pattern to the progress of gastric differentiation; and (2) to understand the regulatory role of T4 on cell proliferation and histological differentiation by altering the thyroidal status of the developing larvae. We observed that (1) in normally developing larvae, cell proliferation increased by early metamorphic climax (MC), remained high until mid‐MC, and decreased to basal levels by late MC; concomitantly, the gastric glands appeared and differentiated in the fundic mucosa, and were complete by late MC; (2) T4 accelerated the differentiation of gastric glands and mucus neck cells, while inhibiting the concomitant increase in cell proliferation observed in controls; and (3) the goitrogen thiourea inhibited both cell proliferation and gastric differentiation compared to controls. These results indicate that T4 is necessary for the three‐fold increase in cell proliferation that occurs in early metamorphic climax, but that high T4 levels promote differentiation at the expense of proliferation. The observed effects would be consistent with the normal, metamorphosis‐related increase in whole body T4. J. Exp. Zool. 290:31–40, 2001. © 2001 Wiley‐Liss, Inc.
Regulation of male sexual development by Sry and Sox9
Authors: Koopman Peter , Bullejos Monica , Bowles Jo 
Published: August 2002

AbstractSry, a gene from the Y chromosome, is known to initiate testis formation and subsequent male differentiation in mammals. A related gene, Sox9, also plays a critical role in testis determination, possibly in all vertebrates. A number of models have been presented regarding the molecular modes of action of these two genes. However, details regarding their regulation, regulatory target genes, and interacting protein factors and co‐factors have not been established with any certainty. In this review, we examine new evidence and re‐examine existing evidence bearing on these issues, in an effort to build up an integrative model of the network of gene activity centred around Sry and Sox9. J. Exp. Zool. 290:463–474, 2001. © 2001 Wiley‐Liss, Inc.
Fluid‐phase endocytosis does not contribute to rapid fluid secretion in the malpighian tubules of the house cricket, Acheta domesticus
Authors: Hazelton S. Renee , Spring Jeffrey H. , Felgenhauer Bruce E. 
Published: August 2002

AbstractWhen the Malpighian tubules (Mt) of the house cricket (Acheta domesticus) are treated with dibutyryl adenosine 3′, 5′‐cyclic monophosphate (db‐cAMP; 1 mM), which causes a doubling in secretion rate, more than 50% of the cell volume is occupied by vesicles within 420 sec of exposure. In view of the fact that the increase in vesiculation occurs concomitantly with stimulated fluid transport, we set out to determine whether the vesicles are formed as a result of fluid‐phase endocytosis (pinocytosis) and subsequently used to transport fluid to the lumen as one means of increasing transport rate. We used fluorescent fluid‐phase markers (Lucifer Yellow Carbohydrazide [LYCH] and Alexa 488 hydrazide) and an electron dense marker (cationized ferritin) to elucidate the degree of endocytosis that occurred with db‐cAMP stimulation. We found that, although some fluid is taken into the cells of the mid‐tubule via endocytosis, it does not coincide with the level of vacuolation present in stimulated tubules. The amount of LYCH transported into the primary urine by the db‐cAMP‐stimulated Mt decreased by 40% as compared to the unstimulated transport, and the rate of transport of LYCH was only 30% of the unstimulated tubules. In summary, our findings do not support the theory that the majority of the vesicles or vacuoles comprise intracellular, endocytotic compartments formed via a basolateral endocytotic pathway. We also found no evidence to support the functioning of vesicles or vacuoles as transcellular “shuttling” mechanisms to move fluid from the basal region to the apical membrane and into the lumen. J. Exp. Zool. 292:1–10, 2002. © 2002 Wiley‐Liss, Inc.
Identification and characterization of proteases involved in specific proteolysis of vitellogenin and yolk proteins in salmonids
Authors: Hiramatsu Naoshi , Ichikawa Norimasa , Fukada Haruhisa , Fujita Toshiaki , Sullivan Craig V. , Hara Akihiko 
Published: August 2002

AbstractA pepstatin A‐sensitive enzyme involved in yolk formation was purified from the masu salmon (Oncorhynchus masou) ovary using in vitro generation of yolk proteins from purified vitellogenin to assay enzymatic activity. Purification of the enzyme involved precipitation of ovarian extracts by water and ammonium sulfate followed by five steps of column chromatography. After SDS‐PAGE and Western blotting, the purified enzyme appeared as a single ∼42 kDa band that was immunoreactive to anti‐human cathepsin D. The course of proteolytic cleavage of the three major yolk proteins (lipovitellin, β′‐component, and phosvitin) in fertilized masu salmon and Sakhalin taimen (Hucho perryi) eggs and embryos was visualized by SDS‐PAGE and Western blotting using specific antisera. Major yolk protein bands appeared in positions corresponding to 92 kDa, 68 kDa, and 22 kDa (lipovitellin‐derived peptides), as well as 17 kDa (β′‐component). During embryo development, the 92 kDa and 22 kDa bands gradually decreased in intensity, becoming undetectable in alevins. The 68 kDa band and a minor 24 kDa band became more intense after the eyed stage. Two additional peptides, corresponding to 40 and 28 kDa, newly appeared in alevins. During embryonic growth, the β′‐component band (17 kDa) persisted and phosvitin appeared to be progressively dephosphorylated. In vitro analysis of lipovitellin proteolysis indicated that the enzyme involved is a Pefabloc SC‐sensitive serine protease. These results demonstrate, for the first time, that a cathepsin D‐like protease and serine proteases play key roles in yolk formation and degradation, respectively, in salmonid fishes. J. Exp. Zool. 292:11–25, 2002. © 2002 Wiley‐Liss, Inc.
Directional sensitivity of wind‐sensitive giant interneurons in the cave cricket Troglophilus neglectus
Authors: Schrader Š. , Horseman G. , Čokl A. 
Published: August 2002

AbstractUnlike the situation in most cockroach and cricket species studied so far, the wind‐sensitive cerci of the cave cricket Troglophilus neglectus Krauss (Rhaphidophoridae, Orthoptera) are not oriented parallel to the body axis but perpendicular to it. The effects of this difference on the morphology, and directional sensitivity of cercal giant interneurons (GIs), were investigated. In order to test the hypothesis that the 90° change in cercal orientation causes a corresponding shift in directional sensitivity of GIs, their responses in both the horizontal and vertical planes were tested.One ventral and four dorsal GIs (corresponding to GIs 9‐1a and 9‐2a, 9‐3a, 10‐2a, 10‐3a of gryllid crickets) were identified. The ventral GI 9‐1a of Troglophilus differed somewhat from its cricket homologue in its dendritic arborisation and its directional sensitivity in the horizontal plane. The morphology and horizontal directionality of the dorsal GIs closely resembled that of their counterparts in gryllids. In the vertical plane, the directionality of all GIs tested was similar. They were all excited mainly by wind puffs from the axon‐ipsilateral quadrant. The results suggest that directional sensitivity to air currents in the horizontal plane is maintained despite the altered orientation of the cerci. This is presumably due to compensatory modifications in the directional pReferences of the filiform hairs. J. Exp. Zool. 292:73–81, 2002. © 2002 Wiley‐Liss, Inc.
Acyclic edge colorings of graphs
Authors: Alon Noga , Sudakov Benny , Zaks Ayal 
Published: August 2002

AbstractA proper coloring of the edges of a graph G is called acyclic if there is no 2‐colored cycle in G. The acyclic edge chromatic number of G, denoted by a′(G), is the least number of colors in an acyclic edge coloring of G. For certain graphs G, a′(G) ≥ Δ(G) + 2 where Δ(G) is the maximum degree in G. It is known that a′(G) ≤ 16 Δ(G) for any graph G. We prove that there exists a constant c such that a′(G) ≤ Δ(G) + 2 for any graph G whose girth is at least cΔ(G) log Δ(G), and conjecture that this upper bound for a′(G) holds for all graphs G. We also show that a′(G) ≤ Δ + 2 for almost all Δ‐regular graphs. © 2001 John Wiley & Sons, Inc. J Graph Theory 37: 157–167, 2001
General properties of some families of graphs defined by systems of equations
Authors: Lazebnik Felix , Woldar Andrew J. 
Published: August 2002

AbstractIn this paper we present a simple method for constructing infinite families of graphs defined by a class of systems of equations over commutative rings. We show that the graphs in all such families possess some general properties including regularity and biregularity, existence of special vertex colorings, and existence of covering maps—hence, embedded spectra—between every two members of the same family. Another general property, recently discovered, is that nearly every graph constructed in this manner edge‐decomposes either the complete, or complete bipartite, graph which it spans. In many instances, specializations of these constructions have proved useful in various graph theory problems, but especially in many extremal problems. A short survey of the related results is included. We also show that the edge‐decomposition property allows one to improve existing lower bounds for some multicolor Ramsey numbers. © 2001 John Wiley & Sons, Inc. J Graph Theory 38: 65–86, 2001
School education and HIV control in sub‐Saharan Africa: from discord to harmony?
Authors: Gregson Simon , Waddell Heather , Chandiwana Stephen 
Published: August 2002

AbstractHIV is widely regarded as a disease of poverty and ignorance. However, within sub‐Saharan Africa, more developed countries and sub‐populations appear to have higher levels of HIV prevalence. This paper considers the evidence and possible reasons for this, by focusing on the relationships between education and the spread of HIV at the macro and micro levels. It is concluded that more educated populations are initially particularly vulnerable to HIV but are also better equipped to mount effective responses. Expanding provision of and access to secondary education could facilitate HIV control but is severely hampered by the morbidity and mortality effects of HIV epidemics. Efforts to sustain and increase education levels and to reduce HIV infections should therefore be mutually re‐enforcing but will require extensive resources. Copyright © 2001 John Wiley & Sons, Ltd.
Syntheses of 2H‐labelled dihydropyrimidinediones and their metabolites
Authors: Heinkele Georg , Hofmann Ute , Opitz Joachim , Mürdter Thomas E. 
Published: August 2002

AbstractStarting with uracil or thymine, [5,5,6,6‐2H4]‐dihydrouracil and [5,6,6,α,α,α,‐2H6]‐dihydrothymine were synthesised in high yields by catalytic deuteriation. Subsequent hydrolyses resulted in the corresponding β‐ureidoalkanoic acids and β‐aminoacids. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis of piperidinyl and pyrrolidinyl butyrates for potential In Vivo measurement of cerebral butyrylcholinesterase activity
Authors: Kikuchi Tatsuya , Fukushi Kiyoshi , Ikota Nobuo , Ueda Takao , Nagatsuka Shin‐ichiro , Arano Yasushi , Irie Toshiaki 
Published: August 2002

AbstractBiochemical changes in postmortem brains of Alzheimer's disease patients include decreased acetylcholinesterase and choline acetyl transferase activity, indicating reduced activity of the central cholinergic system, while butyrylcholinesterase (BChE) activity increases. A method that can measure regional BChE activity in the brain in vivo may be useful for investigating the relationship between BChE and Alzheimer's disease. Seven compounds, either piperidinyl or pyrrolidinyl butyrates, were synthesized as BChE substrate radiotracers to map central BChE activity in vivo by positron emission tomography (PET). 14C‐labeled compounds were assayed to determine their hydrolysis rates by BChE and the partition coefficient. The five esters of secondary alcohols had lipophilic properties sufficient to pass readily through the blood‐brain barrier while the metabolites were sufficiently hydrophilic to be retained in the brain. The esters showed moderate hydrolysis rates by BChE and high specificity for BChE relative to acetylcholinesterase, while two esters of primary alcohols were hydrolyzed too rapidly to estimate reliably the local cerebral BChE activity. From these results, we conclude that one or more of these five esters, when labeled with 11C, would be a useful tracer for quantification of BChE activity by PET. Copyright © 2001 John Wiley & Sons, Ltd.
The synthesis of the αvβ3 integrin receptor ligand [125I]L‐775,219
Authors: Hamill Terence G. , Duggan Mark E. , Perkins Jim J. 
Published: August 2002

AbstractThe αvβ3 integrin receptor ligand [125I]L‐775,219, 1c, was synthesized for use in an in vitro receptor binding assay with high specific activity (>1500 Ci/mmol) and a radiochemical yield of 15–20%. Conversion of iodide 1b to the corresponding aryl trimethylstannane 2, followed by radioiodination using Na125I/iodobead gave 1c. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis of labeled galactosylhydroxylysine
Authors: Adamczyk Maciej , Reddy Rajarathnam E. , Rege Sushil D. 
Published: August 2002

AbstractA concise synthesis of isotopically labeled galactosylhydroxylysine (2) was achieved via glycosylation of labeled hydroxylysine derivative (3) with (+)‐acetobromo‐α‐D‐galactose (4) and subsequent hydrolysis in good overall yield. The hydroxylysine derivative (3) was prepared from (S)‐(−)‐methyl‐2‐[bis‐(tert‐butoxycarbonyl)amino]‐5‐oxopentanoate (4) with the introduction of label (13CD2) via a Wittig reaction using 13CD3PPh3I. Copyright © 2001 John Wiley & Sons, Ltd.
Comparative anatomy of excretory organs in vestimentiferan tube worms (Pogonophora, Obturata)
Authors: Schulze Anja 
Published: August 2002

AbstractIn the past, the excretory systems of only few vestimentiferan species have been examined in detail. This study presents comparative data on eight species on the basis of histological serial sections. Ridgeia piscesae was studied by transmission electron microscopy. All species examined possess a central excretory organ consisting of numerous small branching and intertwined excretory tubules. These are connected to voluminous glandular excretory ducts that lead to the exterior by single or paired excretory pores located at the anterior end of the vestimentum. A comparative analysis shows differences among the species with regard to several features, such as the number of excretory pores, presence/absence of excretory grooves and papillae, position of the excretory organ relative to the brain, and the shape of the excretory ducts. Neither podocytes nor coelomoducts could be detected; therefore, there is no indication of the presence of metanephridia. The vestimentiferan excretory system shows some similarities with the design in Athecanephria (Pogonophora, Perviata) and a general resemblance to the design in sabellid polychaetes, even though in the latter metanephridia are clearly present. J. Morphol. 250:1–11, 2001. © 2001 Wiley‐Liss, Inc.
Mass allometry of the appendicular skeleton in terrestrial mammals
Authors: Christiansen Per 
Published: August 2002

AbstractMost analyses on allometry of long bones in terrestrial mammals have focused on dimensional allometry, relating external bone measurements either to each other or to body mass. In this article, an analysis of long bone mass to body mass in 64 different species of mammals, spanning three orders of magnitude in body mass, is presented. As previously reported from analyses on total skeletal mass to body mass in terrestrial vertebrates, the masses of most appendicular bones scale with significant positive allometry. These include the pectoral and pelvic girdles, humerus, radius+ulna, and forelimb. Total hindlimb mass and the masses of individual hindlimb bones (femur, tibia, and metatarsus) scale isometrically. Metapodial mass correlates more poorly with body mass than the girdles or any of the long bones. Metapodial mass probably reflects locomotor behavior to a greater extent than do the long bones. Long bone mass in small mammals (<50 kg) scales with significantly greater positive allometry than bone mass in large (>50 kg) mammals, probably because of the proportionally shorter long bones of large mammals as a means of preserving resistance to bending forces at large body sizes. The positive allometric scaling of the skeleton in terrestrial animals has implications for the maximal size attainable, and it is possible that the largest sauropod dinosaurs approached this limit. J. Morphol. 251:195–209, 2002. © 2002 Wiley‐Liss, Inc.
Muscular anatomy of the millipede Phyllogonostreptus nigrolabiatus (Diplopoda: Spirostreptida) and its bearing on the millipede “thorax”
Authors: Wilson Heather M. 
Published: August 2002

AbstractThe muscular anatomy of the millipede Phyllogonostreptus nigrolabiatus (Newport, 1844) (Diplopoda; Spirostreptida; Harpagophoridae) is comprehensively surveyed. The musculature of the first three postcollum pleurotergites, the “thorax,” and their associated appendages was found to be more complex than that of the postthoracic rings. It is hypothesized that the musculature of the postthoracic segments is derived relative to that of the thoracic segments, which retain primitively free sternites and are not diplosegments. This hypothesis is discussed relative to previous hypotheses positing that the anteriormost three leg‐bearing rings in millipedes are diplosegments. The musculature of spirostreptid gonopods is described in detail for the first time. Comparison of the cephalic musculature is made with previously described musculature in Julida showing that, while many aspects of the musculature are conserved, there exist interordinal differences, documenting the potential utility of comparative anatomical studies for resolving millipede phylogeny. J. Morphol. 251:256–275, 2002. © 2002 Wiley‐Liss, Inc.
Selective infection of E. coli as a function of a specific molecular interaction
Authors: Nilsson Nina , Karlsson Fredrik , Rakonjac Jasna , Borrebaeck Carl A. K. 
Published: August 2002

AbstractSelective infection of phage is when the bacterial infection depends on the specific molecular interaction between an antigen and a phage‐displayed protein sequence such as an antibody. Engineering of the normal infection into pathways, directed by a specific protein–protein interaction, has raised several mechanistic questions. Here, we address the type of display and the affinity between the interacting pairs. The deleted phage R408d3 was used for the first time in selective infection and was shown to exhibit a superior performance compared to the VCSM13 phage. Furthermore, the affinity between the interacting pairs also affected the selective infection process and a correlation between affinity and infection efficiency was detected, thus implying that selective infection is the method of choice for selection of rare high‐affinity interactions in molecular libraries. Copyright © 2002 John Wiley & Sons, Ltd.