bluuebunny/crossref_metadata_2025 huggingface dataset:
The potential for establishment of axial temperature profiles during solid‐state fermentation in rotating drum bioreactors
Authors: Mitchell David A. , Tongta A. , Stuart D. M. , Krieger N.
Published: September 2002

The mixing and heat transfer phenomena within rotating drum bioreactors (RDBs) used for solid‐state fermentation processes are poorly studied. The potential for the establishment of axial temperature gradients within the substrate bed was explored using a heat transfer model. For growth of Aspergillus oryzae on wheat bran within a 24 L RDB with air at a superficial velocity of 0.0023 m s−1 and 15% relative humidity, the model predicts an axial gradient between the air inlet and outlet of 2°C during rapid growth, compared to experimental axial temperature gradients of between 1 and 4°C. Undesirably high temperatures occur throughout the bed under these operating conditions, but the model predicts that good temperature control can be achieved using humid air (90% relative humidity) at superficial velocities of 1 m s−1 for a 204 L RDB. For a 2200 L RDB, good temperature control is predicted with superficial velocities as low as 0.4 m s−1 with the airflow being switched from 90% to 15% relative humidity whenever the temperature at the outlet end of the drum exceeds the optimal temperature for growth. This work suggests that significant axial temperature gradients can arise in those RDBs that lack provision for axial mixing. It is therefore advisable to use angled lifters within RDBs to promote axial mixing. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 114–122, 2002
Selective separation of cis‐trans geometrical isomers of β‐carotene via CO2 supercritical fluid extraction
Authors: Gamlieli‐Bonshtein Iris , Korin Eli , Cohen Smadar
Published: September 2002

We investigated a novel method for the selective separation of β‐carotene isomers from a freeze‐dried powder of the algae Dunaliella bardawil using supercritical fluid extraction. The separation method relies on the different dissolution rate of the 9Z and all‐E isomers of β‐carotene in SC‐CO2. At first, the equilibrium solubility of the two isomers in SC‐CO2 was determined at the extraction conditions of 44.8 MPa and 40°C. The solubility of the 9Z isomer was found to be nearly 4 times higher than that of the all‐E isomer (1.92 × 10−5 g all‐E isomer/g CO2 compared to 7.64 × 10−5 g 9Z isomer/g CO2). When supercritical fluid extraction was applied to a carotenoid concentrate from the algae (29 wt% β‐carotene) or a freeze‐dried powder of the algae (3.1% β‐carotene), a selective separation of the 9Z/all‐E isomers of β‐carotene was obtained. Thirty‐nine percent recovery of β‐carotene with 80% purity of 9Z isomer was achieved at the initial stages of extraction (40 mL CO2). The extraction rate of β‐carotene from the freeze‐dried algae powder was slower than that from the carotenoid concentrate, resulting in a reduction in the recovery and purity of the 9Z isomer. This indicates that even at the initial stage of the extraction the internal mass resistance is significant. Isomer purity and recovery could be enhanced upon grinding of the algae powder. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 169–174, 2002.
Sensitivity function‐based model reduction: A bacterial gene expression case study
Authors: Smets Ilse , Bernaerts Kristel , Sun Jun , Marchal Kathleen , Vanderleyden Jos , Van Impe Jan
Published: September 2002

Mathematical models used to predict the behavior of genetically modified organisms require 1) a (rather) large number of state variables, and 2) complicated kinetic expressions containing a large number of parameters. Since these models are hardly identifiable and of limited use in model‐based optimization and control strategies, a generic methodology based on sensitivity function analysis is presented to reduce the model complexity at the level of the kinetics, while maintaining high prediction power. As a case study to illustrate the method and results obtained, the influence of the dissolved oxygen concentration on the cytN gene expression in the bacterium Azospirillum brasilense Sp7 is modeled. As a first modeling approach, available mechanistic knowledge is incorporated into a mass balance equation model with 3 states and 14 parameters. The large differences in order of magnitude of the model parameters identified on the available experimental data indicate 1) possible structural problems in the kinetic model and, associated with this, 2) a possibly too high number of model parameters. A careful sensitivity function analysis reveals that a reduced model with only seven parameters is almost as accurate as the original model. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 195–200, 2002.
Operational intensification by direct product sequestration from cell disruptates: Application of a pellicular adsorbent in a mechanically integrated disruption‐fluidised bed adsorption process
Authors: Jahanshahi Mohsen , Sun Yan , Santos Everaldo , Pacek Andrzej , Teixera Franco Telma , Nienow Alvin , Lyddiatt Andrew
Published: September 2002

A novel prototype adsorbent, designed for intensified fluidised bed adsorption processes, was assembled by the emulsification coating of 4% (w/v) porous agarose upon a zirconia‐silica solid core. The adsorbent, designated ZSA (particle density 1.75 g/ml, maximum pellicle depth 40 μm), was subjected to physical and biochemical comparison with the performance of two commercial adsorbents (Streamline and Macrosorb K4AX). Bed expansion qualities and hydrodynamic characteristics (N, Daxl and Bo) of ZSA demonstrated a marked robustness in the face of elevated velocities (up to 550 cm/h) and biomass loading (up to 30% (ww/v)) disrupted yeast cells. Cibracron Blue derivatives of the pellicular prototype (ZSA‐CB), evaluated in the batch and fluidised bed recovery of glyceraldehyde 3‐phosphate dehydrogenase (G3PDH) from unclarified yeast disruptates, exhibited superior capacities and adsorption/desorption performance to the commercial derivatives. These advanced physical and biochemical properties facilitated a demonstration of the direct, mechanical coupling of bead‐milling and fluidised bed adsorption in a fully integrated process for the accelerated recovery of G3PDH from yeast. The generic application of such pellicular adsorbents and integrated processes to the recovery of labile, intracellular products is discussed. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 201–212, 2002.
General O‐glycosylation of 2‐furfuryl alcohol using β‐glucuronidase
Authors: Martin Brett D. , Welsh Eric R. , Mastrangelo Jonathan C. , Aggarwal Renu
Published: September 2002

β‐Glucuronidase from bovine liver is able to catalyze transfer of several carbohydrates to furfuryl alcohol, an acid‐sensitive diene, with transfer yields as high as 84%. Carbohydrates that were transferred in yields of 30% or higher include gluco‐, galacto‐, xylo‐, and fucopyranose. Small variations in the configuration of the substrate hydroxyls lead to large variations in the catalytic behavior of the enzyme in terms of both the initial reaction velocities and the final ratios of transfer‐to‐hydrolysis. The high transfer yields and surprising nonspecificity towards carbohydrate suggest that the enzyme may be a versatile tool for the general O‐glycosylation of dienic alcohols. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 222–227, 2002
Separating lysozyme from bacteriophage P22 in two‐phase aqueous micellar systems
Authors: Kamei Daniel T. , King Jonathan A. , Wang Daniel I. C. , Blankschtein Daniel
Published: September 2002

This communication demonstrates that two‐phase aqueous mixed (nonionic/ionic) micellar systems have the potential for improving the separation of proteins from viruses. Specifically, two separation experiments were performed to show that the addition of the anionic surfactant sodium dodecyl sulfate (SDS) to the two‐phase aqueous nonionic n‐decyl tetra(ethylene oxide) (C10E4) micellar system increases the yield of a model net positively charged protein, lysozyme, in the micelle‐rich phase from 75 to 95%, while still maintaining approximately the same yield of a model net negatively charged virus, bacteriophage P22, in the micelle‐poor phase (97% vs. 98%). © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 233–236, 2002.
In vitro gene expression dissected: chemostat surgery for Mycobacterium tuberculosis
Authors: James Brian W. , Bacon Joanna , Hampshire Tobias , Morley Kim , Marsh Philip D.
Published: September 2002

A unique approach, combining defined and reproducible in vitro models with DNA microarrays, has been developed to study environmental modulation of mycobacterial gene expression. The gene expression profiles of samples of Mycobacterium tuberculosis, from independent chemostat cultures grown under defined and reproducible conditions, were found to be highly correlated. This approach is now being used to study the effect of relevant stimuli, such as limited oxygen availability, on mycobacterial gene expression. A modification of the chemostat culture system, enabling large‐volume controlled batch culture, has been developed to study starvation survival. Cultures of M. tuberculosis have been maintained under nutrient‐starved conditions for extended periods, with 106–107 bacilli surviving in a culturable state after 100 days. The design of the culture system has made it possible to control the environment and collect multiple time‐course samples to study patterns of gene expression. These studies demonstrate that it is possible to perform long‐term studies and obtain reproducible expression data using controlled and defined in vitro models. Copyright © 2002 John Wiley & Sons, Ltd.
The use of microarray technology for the analysis of Streptococcus pneumoniae
Authors: McCluskey Jackie , Dowson Christopher G. , Mitchell Timothy J.
Published: September 2002

Streptococcus pneumoniae is an important human pathogen associated with pneumonia, septicaemia, meningitis and otitis media. It is estimated to result in over 3 million child deaths worldwide every year and an even greater number of deaths among the elderly. Prior to the complete sequencing of the genomes of S. pneumoniae TIGR4 (serotype 4) and S. pneumoniae R6 (serotype 2), we designed a custom miniarray consisting of 497 pneumococcal genes. The overall objectives of our microarray investigations were, first, to assess the genetic diversity between different S. pneumoniae serotypes, clinical isolates and also different Streptococcus species; second, we aimed to use microarray technology to examine the mechanisms by which environmental factors influence pneumococcal gene expression, and ultimately to further the understanding of how these changes in gene expression are achieved and how they may alter the virulence of the organism. Copyright © 2002 John Wiley & Sons, Ltd.
Microarrays for public health: genomic epidemiology of tuberculosis
Authors: Shafi Jamila , Andrew Peter W. , Barer Michael R.
Published: September 2002

In response to a large local school‐based outbreak of tuberculosis, we have been evaluating the utility of microarray bacterial genomic analysis in outbreak management. After initial comparison of the isolate from the index case with Mycobacterium tuberculosis H37Rv, it was possible to design robust PCRs directed towards strain‐specific deletions. Rapid PCR analysis of isolates proved valuable in determining whether or not other isolates were compatible with the outbreak strain and further microarray studies revealed genetic markers that could be used to discriminate between locally circulating strains. We suggest that this approach forms the basis for developing rapid local genotyping schemes applicable to M. tuberculosis and that application to other pathogens warrants consideration. Copyright © 2002 John Wiley & Sons, Ltd.
The curse of normalization
Authors: Wolkenhauer Olaf , Möller‐Levet Carla , Sanchez‐Cabo Fatima
Published: September 2002

Despite its enormous promise to further our understanding of cellular processes involved in the regulation of gene expression, microarray technology generates data for which statistical pre‐processing has become a necessity before any interpretation of data can begin. The process by which we distinguish (and remove) non‐biological variation from biological variation is called normalization. With a multitude of experimental designs, techniques and technologies influencing the acquisition of data, numerous approaches to normalization have been proposed in the literature. The purpose of this short review is not to add to the many suggestions that have been made, but to discuss some of the difficulties we encounter when analysing microarray data. Copyright © 2002 John Wiley & Sons, Ltd.
Haemophilus influenzae microarrays: virulence and vaccines
Authors: Ali Tahir R. , Kroll J. Simon , Langford Paul R.
Published: September 2002

In 1995 the genome sequence of the Haemophilus influenzae KW20 (Rd) strain was published, the first available for a free‐living organism. The genome has been invaluable in global strategies to identify certain virulence‐related genes, e.g. those involved in LPS synthesis, and also essential genes, but there is a paucity of whole‐genome transcriptome studies. We have now constructed a whole‐genome array consisting of genes from Rd, additional genes identified in other strains of H. influenzae and controls (from eukaryotic sources and other bacteria). We intend to use this array in studies aimed at understanding the bacterium's basic metabolism and its response to changing environments; deciphering global regulatory networks (by comparison of wild‐type and mutant strains); and identifying genes expressed in vivo. The use of H. influenzae DNA arrays combined with proteomic approaches will enhance our understanding of the metabolism and virulence of the organism. Additionally, the genome sequence of a non‐typable H. influenzae strain is in progress. The sequence from this isolate will be invaluable not only in identifying potential novel antibiotic targets and putative vaccine candidates but also in the design of a microarray for genome‐typing purposes. Copyright © 2002 John Wiley & Sons, Ltd.
Can replication save noisy microarray data?
Authors: Wernisch Lorenz
Published: September 2002

Microarray experiments are multi‐step processes. At each step — the growth of cultures, extraction of mRNA, reverse transcription, labelling, hybridization, scanning, and image analysis — variation and error cannot be completely avoided. Estimating the amount of such noise and variation is essential, not only to test for differential expression but also to suggest at which level replication is most effective.

Replication and averaging are the key to the estimation as well as the reduction of variability. Here I discuss the use of ANOVA mixed models and of analysis of variance components as a rigorous way to calculate the number of replicates necessary to detect a given target fold‐change in expression levels. Procedures are available in the package YASMA (http://www.cryst.bbk.ac.uk/wernisch/yasma.html) for the statistical data analysis system R (http://www.R‐project.org). Copyright © 2002 John Wiley & Sons, Ltd.
Double trouble: maternal depression and alcohol dependence as combined factors in child and family social work
Authors: Woodcock Johanna , Sheppard Michael
Published: September 2002

This study, part of a large programme of research incorporating four child and family care teams, focuses on the combined effects of alcohol dependence alongside clinical depression in mothers. A comparison is made between women who were clinically depressed and women who were both clinically depressed and alcohol dependent. The latter group had significantly higher levels of difficulty in social relationship, health, child, and particularly parenting problems. When considered alongside the intensity, duration and range of intervention required, the results indicated that there is considerable concern about the ‘dangerousness’ of this particular group with major implications for policy and practice. Copyright © 2002 John Wiley & Sons, Ltd.
‘God, she's gonna report me’: the ethics of child protection in poverty research
Authors: Bostock Lisa
Published: September 2002

The ethics of social research with children has been the source of considerable debate. In particular, issues of how to address potential disclosures of child abuse have been highlighted. What ethical implications are raised, however, when children are the indirect focus of the research? This paper explores the ethical dilemmas of conducting research with mothers about their experiences of caring for children. It is based on qualitative research with 30 mothers on low incomes. The paper concludes that strategies to tackle structural disadvantage as well as those that take account of individual risk are key features of future child welfare. Copyright © 2002 John Wiley & Sons, Ltd.
Actin‐based phagosome motility
Authors: Zhang Fangliang , Southwick Frederick S. , Purich Daniel L.
Published: September 2002

Despite abundant evidence of actin's involvement at the particle internalization stage of phagocytosis, little is known about whether phagosomes undergo the same type of actin‐based motility as observed with endocytic vesicles or such intracellular pathogens as Listeria and Shigella. By employing video microscopy to follow the fate of latex bead‐containing phagosomes within the cytoplasm of bone marrow macrophages, we have made the novel observation of actin‐based phagosome motility. Immunofluorescence microscopy confirmed that phagosomes containing IgG‐opsonized, bovine serum albumin (or BSA) ‐coated or uncoated latex beads all formed actin‐rich rocket tails that persisted only during a brief, 1–2 min period of actin‐based motility. Average speeds of actin‐based phagosome motility were 0.13 ± 0.06 μm/s for IgG‐coated beads, 0.14 ± 0.04 μm/s for BSA‐coated beads, and 0.11± 0.03 μm/s for uncoated beads. Moreover, the speeds and motile‐phase duration of each type of phagosome were comparable to the behavior of pinosomes [Merrifield et al., 1999: Nat. Cell Biol. 1:72–74.]. Determination of optimal conditions for observing and analyzing actin‐based phagosome motility should facilitate future investigations of phagocytosis and phagosome maturation. Cell Motil. Cytoskeleton 53:81–88, 2002. © 2002 Wiley‐Liss, Inc.
A tissue‐specific exon of myosin Va is responsible for selective cargo binding in melanocytes
Authors: Au Josephine Sui‐Yan , Huang Jian‐Dong
Published: September 2002

Class V myosins are molecular motors used for intracellular transportation and organelle tethering. The mouse Myosin Va (MyoVa) is encoded by the dilute locus, which is alternatively spliced to generate several tissue specific isoforms. The tail of MyoVa is the putative cargo‐binding domain. To determine the functions of different isoforms of MyoVa and the minimal cargo‐binding region, we tagged various isoforms and different portions of the mouse MyoVa tail with a green fluorescent protein and examined their intracellular localizations in the mouse melan‐a cells. We found that the amino acid sequence encoded by an alternatively spliced exon, exon F, is necessary for the selective binding of MyoVa to melanosome. The MyoVa isoforms lacking this amino acid sequence are not targeted to the melanosomes, but localized to the perinuclear region instead. These findings suggested that MyoVa is able to bind to more than one types of cargos, with the selectivities determined by alternative spliced sequences. Cell Motil. Cytoskeleton 53:89–102, 2002. © 2002 Wiley‐Liss, Inc.
Laminin‐1 increases motility, path‐searching, and process dynamism of rat and mouse Muller glial cells in vitro: Implication of relationship between cell behavior and formation of retinal morphology
Authors: Méhes Előd , Czirók András , Hegedüs Balázs , Vicsek Tamás , Jancsik Veronika
Published: September 2002

Spatial correlation was observed between the localization of laminin‐1 at the inner limiting membrane (ILM) and extensive Muller glial process arborization in the same area, as demonstrated by immunolabeling of Muller glial processes and laminin‐1 in rat retinae in situ. To test if this spatial correlation is due to a functional relationship, we investigated the impact of laminin‐1 on the motility of cultured primary rat and mouse retinal Muller glial cells by statistical analysis of computer‐controlled videomicroscopic time‐lapse images. We demonstrate that laminin‐1 increases motility and path‐searching activity of Muller cells in vitro and it also enhances the cells' process formation/withdrawal dynamism. The increase in path‐searching activity and cell process dynamism indicates that there is a functional relationship between laminin‐1 and Muller glial cells presumably involving signaling towards the cytoskeleton. We hypothesize that laminin‐1 is involved in process arborization of Muller cells at the vitread border of the retina resulting in the formation of the functional barrier made up of Muller glial endfeet. Cell Motil. Cytoskeleton 53:203–213, 2002. © 2002 Wiley‐Liss, Inc.
Arachidonic acid signaling to the cytoskeleton: The role of cyclooxygenase and cyclic AMP‐dependent protein kinase in actin bundling
Authors: Glenn Honor L. , Jacobson Bruce S.
Published: September 2002

Cell adhesion to the extracellular matrix via integrins is a primary regulatory mechanism for numerous aspects of normal cellular function. However, disruption of this interaction can result in pathology. For example, one characteristic of transformed cells is loss of adhesion dependence for viability. Adhesion also is a necessary step in tumor metastasis. It has been shown previously, in HeLa cells, that cell attachment to a gelatin‐coated substrate results in the release of arachidonic acid, which is metabolized by lipoxygenase. A subsequent cascade of lipid second messengers activates protein kinase C, which triggers actin polymerization leading to cell spreading. We now demonstrate by inhibitor studies and biochemical analysis, a parallel branch of arachidonic acid signaling that reorganizes the actin cytoskeleton into small bundles. This branch of the pathway is initiated by cyclooxygenase, which generates prostaglandins and causes the downstream activation of cyclic AMP‐dependent protein kinase. This work elucidates a system of interacting signals in which arachidonic acid functions at a branch point in cytoskeletal signaling. The lipoxygenase branch provides polymerized actin; these actin filaments act as a substrate for the cylooxygenase branch to generate actin bundles. Cell Motil. Cytoskeleton 53:239–250, 2002. © 2002 Wiley‐Liss, Inc.
Correlation between CGRP immunoreactivity and firing activity in cat abducens motoneurons
Authors: González‐Forero David , De La Cruz Rosa R. , Delgado‐García José María , Alvarez Francisco J. , Pastor Angel M.
Published: September 2002

A relationship between motoneuron activity and calcitonin gene‐related peptide (CGRP) expression was previously suggested based on indirect inferences. We show here a positive correlation between CGRP immunoreactivity and firing activity in an experimental model that used tetanus neurotoxin (TeNT) to alter basal firing levels. A low dose (0.5 ng/kg) of TeNT injected in the lateral rectus muscle raised the basal firing rate of ipsilateral abducens motoneurons, estimated as the firing rate at straight‐ahead gaze (F0); the firing rate returned to control values after 2 weeks. In contrast, a high dose (5 ng/kg) of TeNT decreased basal firing, which recovered slowly over a 7‐week period. Expression of CGRP immunoreactivity by abducens motoneurons, preferentially related to βCGRP gene expression, was analyzed during these periods of altered firing activity. The number of CGRP‐immunofluorescent abducens motoneurons increased to ∼120% by 7 days after low‐dose TeNT, to include all available motoneurons in the nucleus. In addition, the average CGRP immunofluorescence optical density inside motoneurons almost doubled after 4 days and returned toward control values in the following 2 weeks. In contrast, a high‐dose injection of TeNT reduced the number of CGRP‐immunofluorescent motoneurons to 5.4% of control 7 days post injection, and the number returned to 77.6% after 42 days. CGRP immunofluorescence intensity inside motoneurons was also reduced. Regression analysis of F0 values with either the number of CGRP‐immunolabeled motoneurons, their average immunofluorescence intensity, or both factors combined resulted in positive correlations with regression coefficients of 0.87 or higher. Therefore, CGRP expression and firing activity in abducens motoneurons are positively correlated. J. Comp. Neurol. 451:201–212, 2002. © 2002 Wiley‐Liss, Inc.
Development and distribution of the peptidergic system in larval and adult Patiriella: Comparison of sea star bilateral and radial nervous systems
Authors: Byrne Maria , Cisternas Paula
Published: September 2002

Development of the larval peptidergic system in the sea star Patiriella regularis and structure of the adult nervous system in Patiriella species were documented in an immunofluorescence investigation using antisera to the sea star neuropeptide GFNSALMFamide 1 (S1) and confocal microscopy. P. regularis has planktotrophic development through bipinnaria and brachiolaria larvae. In early bipinnaria, two groups of immunoreactive cells appeared on either side of the anterior region and proliferated to form a pair of dorsolateral ganglia. The ganglia gave rise to fine varicose fibres that innervated the preoral and adoral ciliated bands. Peptidergic cells also innervated the postoral ciliated band, and a nerve tract connected the pre‐ and postoral bands. Fully developed bipinnaria had a well‐developed peptidergic system, the organisation of which reflected the bilateral larval body plan. As the brachiolar attachment complex differentiated at the anterior end, the ganglia became positioned on either side of the anterior projection, from which they innervated the complex. It is suggested, based on the distribution of S1‐like immunoreactivity in association with ciliary and attachment structures, that the peptidergic system functions in modulation of feeding, swimming, and settlement. The larval peptidergic system degenerates as the larval body is resorbed during metamorphosis. In adults, S1‐like immunoreactivity was intense in the axonal region of the ectoneural nervous system and in hyponeural perikarya. Immunoreactive cells in the neuroepithelium connected with the surface and may be sensory. Examination of immunoreactivity in several Patiriella species attests to the highly conserved organisation of the peptidergic system in adult asteroids. J. Comp. Neurol. 451:101–114, 2002. © 2002 Wiley‐Liss, Inc.
Genetic influences on secondary degeneration and wound healing following spinal cord injury in various strains of mice
Authors: Inman Denise , Guth Lloyd , Steward Oswald
Published: September 2002

Various inbred strains of mice exhibit dramatic differences in sensitivity to excitotoxic cell death induced by systemic injections of kainic acid (KA). The present study evaluates whether the same strains are also differentially sensitive to secondary degeneration after spinal cord injury, in which excitotoxic cell death is thought to play a pathogenic role. Spinal cord crush injuries were produced at T9 in two inbred strains that are resistant to KA‐induced excitotoxic cell death (C57Bl/6 and Balb/c) and four strains that are sensitive (CD‐1, FVB/N, 129T2 Sv/EMS, and C57Bl/10). The spinal cord was prepared for light microscopy at intervals from 1 to 56 days postinjury, and the area of damaged tissue (termed lesion size) and amount of cavitation were determined by quantitative image analysis. Lesion size increased between 1 and 7 days in all strains and then decreased steadily in a wound‐healing process that occurs uniquely in mice. The extent of cavitation also gradually decreased from 7 to 56 days in all strains. Although lesion area and cavitation decreased in all strains, there were significant differences in lesion size and cavitation across strains. Specifically, lesion areas in the KA‐sensitive strains FVB/N, 129T2 Sv/EMS, and CD‐1 were significantly larger at 56 days postinjury than in the KA‐resistant strains C57Bl/6 and Balb/c. We conclude that the genetic differences that confer resistance and sensitivity to KA‐induced neurotoxicity also modify the secondary degenerative processes that occur after spinal cord injury, so that resistance to excitotoxic injury leads to smaller overall lesions and a more effective wound‐healing response. J. Comp. Neurol. 451:225–235, 2002. © 2002 Wiley‐Liss, Inc.
Differential expression of calretinin and metabotropic glutamate receptor mGluR1α defines subsets of unipolar brush cells in mouse cerebellum
Authors: Nunzi Maria‐Grazia , Shigemoto Ryuichi , Mugnaini Enrico
Published: September 2002

The unipolar brush cell (UBC) is a type of glutamatergic interneuron in the granular layer of the cerebellum. The UBC brush and a single mossy fiber (MF) terminal contact each other within a cerebellar glomerulus, forming a giant synapse. Many UBCs receive input from extrinsic MFs, whereas others are innervated by intrinsic mossy terminals formed by the axons of other UBCs. In all mammalian species so far examined, the vestibulocerebellum is enriched of UBCs that are strongly immunoreactive for the calcium binding protein calretinin (CR) in both the somatodendritic and axonal compartment. UBCs have postsynaptic ionotropic glutamate receptors and extrasynaptic metabotropic glutamate receptors that immunocytochemically highlight their somatodendritic compartment and brush, respectively. In this study on the mouse cerebellum, we present evidence that immunoreactivities to CR and mGluR1α define two distinct UBC subsets with partly overlapping distributions in lobule X (the nodulus). In sections double‐labeled for CR and mGluR1α, the patterns of distributions of CR+/mGluR1α− UBCs and CR−/mGluR1α+ UBCs differed along the mediolateral and dorsoventral axes of the folium. Moreover, mGluR1α+ UBCs outnumbered CR+ UBCs. Both UBC subsets were mGluR2/3, GluR2/3, and NMDAR1 immunoreactive. The different distribution patterns of the two UBC subsets within lobule X suggest that expression of CR or mGluR1α by UBCs may be afferent‐specific and related to the terminal fields of different vestibular MF afferents. J. Comp. Neurol. 451:189–199, 2002. © 2002 Wiley‐Liss, Inc.
Role of Emx2 in the development of the reciprocal connectivity between cortex and thalamus
Authors: López‐Bendito Guillermina , Chan Chun‐Hung , Mallamaci Antonello , Parnavelas John , Molnár Zoltán
Published: September 2002

Emx2 knockout mice appear to show a shift in the areal identity in the cerebral cortex of Emx2 knockout mice, which is matched with altered distribution of thalamocortical projections (Bishop et al. [2000] Science 288:344–3349; Mallamaci et al. [2000] Nat Neurosci. 3:679–686). We have examined the early establishment of these projections to understand how the altered Emx2 expression results in changes in their cortical targeting. We used carbocyanine dye tracing to visualize thalamocortical and corticofugal projections as well as immunohistochemistry for L1 and TAG‐1, respective markers of the two axonal systems, in wild‐type, heterozygote, and null mutant for Emx2 at embryonic (E) ages ranging from E13.5 to E18.5. These tracing studies demonstrated that, in Emx2 knockout mice, a large proportion of early thalamocortical projections were misrouted at the border between the diencephalon and telencephalon. This abnormality was associated with displaced connectivity of the internal capsule cells at the diencephalic–telencephalic junction. Interestingly, most of the aberrant thalamic projections compensated for the ventral entry to the telencephalon and still ascended to the cortex. Although this early targeting abnormality is associated with the altered Emx2 expression pattern in the cortex, it most probably occurs independently from it, and is related to earlier guidance defects at the diencephalic–telencephalic boundary. These defects might result in the altered and delayed arrival of thalamic projections to the cortex and, thus, contribute to the shifted thalamocortical matching previously observed in the Emx2 knockout mice. J. Comp. Neurol. 451:153–169, 2002. © 2002 Wiley‐Liss, Inc.
Acoustic trauma induces reemergence of the growth‐ and plasticity‐associated protein GAP‐43 in the rat auditory brainstem
Authors: Michler Steffen A. , Illing Robert‐Benjamin
Published: September 2002

We explored the consequences of unilateral acoustic trauma to intracochlear and central nervous system structures in rats. An acoustic trauma, induced by applying click stimuli of 130 dB (sound pressure level; SPL) for 30 minutes, resulted in an instant and permanent threshold shift of 95.92 ± 1.08 dB (SEM) in the affected ear. We observed, as a consequence, a structural deterioration of the organ of Corti. Deprivation‐dependent changes of neurons of the auditory brainstem were determined using antibodies against neurofilament and the growth‐associated protein GAP‐43 and compared with those following cochleotomy, studied earlier. By 231 days posttrauma, spiral ganglion cell bodies and their processes were almost entirely lost from all cochlear regions with destroyed organ of Corti. In the lateral superior olive (LSO) ipsilateral to the trauma, cell bodies of lateral olivocochlear neurons turned transiently GAP‐43 positive within the first 1.5 years posttrauma. The time course of emergence and disappearance of this population of neurons was similar to that found after cochleotomy. Additionally, after noise trauma, principal cells in contralateral LSO and in medial superior olive (MSO) on both sides of the brainstem developed an expression of GAP‐43 that began 3 and 16 days posttrauma, respectively, and lasted for at least 1 year. Such cells were rarely observed after cochleotomy. An unequivocal rise in GAP‐43 immunoreactivity was also found in the neuropil of the inferior colliculus and the ventral cochlear nucleus, both preferentially on the acoustically damaged side. We conclude that the degree and specific cause of sudden unilateral deafness entail specific patterns of plasticity responses in the auditory brainstem, possibly to prevent the neural network dedicated to locate sounds in the environment from delivering erroneous signals centralward. J. Comp. Neurol. 451:250–266, 2002. © 2002 Wiley‐Liss, Inc.
ATP‐binding cassette transporter ABCA2 (ABC2) expression in the developing spinal cord and PNS during myelination
Authors: Zhou Cheng‐Ji , Inagaki Nobuya , Pleasure Samuel J. , Zhao Li‐Xia , Kikuyama Sakae , Shioda Seiji
Published: September 2002

We examined developmental characteristics of the ATP‐binding cassette transporter ABCA2 (or ABC2) ‐expressing cells in rat spinal cord and peripheral nerves. In adult spinal cord, ABCA2 immunoreactivity was detected in lysosome‐like organelles of mature oligodendrocyte cell bodies, and a single specific band was detected by Western blot analysis. In postnatal developing spinal cord, ABCA2 immunolabeling was first detected in a small number of cells restricted to the ventral marginal area and the dorsal funiculus at birth (P0). ABCA2‐positive cells were co‐immunolabeled by O4, a marker for late progenitor and immature oligodendrocytes. At the same time, myelin basic protein was apparent in the same restricted regions. The number of ABCA2 and O4 co‐immunolabeled cells increased quickly in both dorsal and ventral regions from P2 and reached a peak at P8. After transient expression from P0 to P8, O4 labeling in white matter tracts decreased and disappeared. In contrast, ABCA2‐positive oligodendrocytes persisted in gray and white matter throughout the spinal cord into adulthood. These data suggest a role for the ABCA2 transporter in maturation of oligodendrocyte lineage cells and the onset of myelination in the central nervous system. In addition, ABCA2 immunoreactivity was detected in the ciliated region of the ependyma in the central canal from early postnatal development. ABCA2 immunoreactivity was also detected in the Schwann cell lineage in developing spinal nerves and in adult trigeminal and sciatic nerves. ABCA2 was also expressed in numerous undetermined cells distributed in para‐nerve connective tissues and nerve sheaths throughout early postnatal development. These data indicate multiple levels of involvement for ABCA2 in nervous system development especially with strong evidence for a role in myelination. J. Comp. Neurol. 451:334–345, 2002. © 2002 Wiley‐Liss, Inc.
Expression of Vema in the developing mouse spinal cord and optic chiasm
Authors: Runko Erik , Kaprielian Zaven
Published: September 2002

A critical phase of nervous system development is the formation of connections between axons and their synaptic targets. Intermediate targets play important roles in axon pathfinding by supplying growing axons with long‐ and short‐ range guidance cues at decision points along their trajectory. We recently identified Vema as a novel membrane‐associated protein that is expressed at the ventral midline of the developing vertebrate central nervous system (CNS). We report that Vema is expressed in the floor plate, an intermediate target for pathfinding commissural axons located at the ventral midline of the developing mouse spinal cord. Interestingly, Vema expression overlaps with the position of an unique population of neurons situated at the midline of the ventral diencephalon and that function as intermediate targets for pathfinding retinal ganglion cell axons. The distribution of Vema in the developing spinal cord and optic chiasm resembles the expression patterns of a variety of molecules known to play important roles in axon guidance, including Robo2, Neuropilin2, and SSEA. The expression of Vema at two key choice points for pathfinding axons suggests an important role for this protein in regulating axon guidance at the midline of the developing mouse central nervous system. J. Comp. Neurol. 451:289–299, 2002. © 2002 Wiley‐Liss, Inc.
Calcium‐binding proteins map the postnatal development of rat vestibular nuclei and their vestibular and cerebellar projections
Authors: Puyal Julien , Devau Gina , Venteo Stephanie , Sans Nathalie , Raymond Jacqueline
Published: September 2002

We investigated whether three calcium‐binding proteins, calretinin, parvalbumin, and calbindin, could identify specific aspects of the postnatal development of the rat lateral (LVN) and medial (MVN) vestibular nuclei and their vestibular and cerebellar connections. Calretinin levels in the vestibular nuclei, increased significantly between birth and postnatal day (P) 45. In situ hybridization and immunocytochemical staining showed that calretinin‐immunoreactive neurons were mostly located in the parvocellular MVN at birth and that somatic and dendritic growth occurred between birth and P14. During the first week, parvalbumin‐immunoreactive fibers and endings were confined to specific areas, i.e., the ventral LVN and magnocellular MVN, and identified exclusively the maturation of the vestibular afferents. Calbindin was located within the dorsal LVN and the parvocellular MVN and identified the first arrival of the corticocerebellar afferents. From the second week, in addition to labeling vestibular afferents in their specific target areas, parvalbumin was also found colocalized with calbindin in mature Purkinje cell afferents. Thus, the specific spatiotemporal distribution of parvalbumin and calbindin could correspond to two successive phases of synaptic remodeling involving integration of the vestibular sensory messages and their cerebellar control. On the basis of the sequence of distribution patterns of these proteins during the development of the vestibular nuclei, calretinin is an effective marker for neuronal development of the parvocellular MVN, parvalbumin is a specific marker identifying maturation of the vestibular afferents and endings, and calbindin is a marker of the first appearance and development of Purkinje cell afferents. J. Comp. Neurol. 451:374–391, 2002. © 2002 Wiley‐Liss, Inc.
Distribution of calbindin D‐28k in the entorhinal, perirhinal, and parahippocampal cortices of the macaque monkey
Authors: Suzuki Wendy A. , Porteros Angel
Published: September 2002

We examined the distribution of calbindin D‐28k–immunoreactive (CB‐IR) neurons, fibers, and neuropil in the entorhinal (area 28), perirhinal (areas 35 and 36), and parahippocampal (areas TH and TF) cortices in the macaque monkey. Two main findings are reported. First, except for CB‐IR neurogliaform cells that are only observed in the parahippocampal cortex, the morphology of CB‐stained pyramidal and nonpyramidal cells were similar across the three cortical areas examined. Second, we find that the topography of CB staining differed between the three areas. The entorhinal cortex exhibits the most striking gradient of CB staining such that the most anterior and medial portions are most strongly labeled, whereas posterior and lateral areas exhibit only weak labeling. The labeling throughout the perirhinal and parahippocampal cortices is more homogeneous. Area 35 contains only lightly stained neuropil and few CB‐IR cells. Area 36 and areas TH and TF of the parahippocampal cortex contain a moderate to high density of CB‐IR cells and fibers throughout their full rostrocaudal extents, although each area exhibits unique laminar patterns of staining. In all areas examined, the highest density of CB‐positive cells and fibers is observed in superficial layers with lower densities of CB‐positive cells and fibers present in deep layers. These findings, taken together with our current understanding of the connections of these areas may have implications for understanding the circuit properties of the entorhinal, perirhinal, and parahippocampal cortices areas in both normal and disease states. J. Comp. Neurol. 451:392–412, 2002. © 2002 Wiley‐Liss, Inc.
The Weber fraction and asymmetries in luminance thresholds
Authors: Carreño Fernando , Zoido Jesús Manuel
Published: September 2002

Presented in this article is a method for the determination of the Weber fraction by analyzing data obtained from color‐matching experiments. The method is based on a rigorous analysis of the probability density function derived from discrimination judgments made in the xyY space. Analysis shows the thresholds for luminance increments and decrements are shown to be different and asymmetric and the Weber fraction to depend on the target's level of luminance and chromaticity. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 330–334, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10079
Color science applications of the Binet–Cauchy theorem
Authors: Brill Michael H.
Published: September 2002

The Binet–Cauchy theorem, an expansion of the determinant of the product of two nonsquare matrices, is quite useful in deriving theorems about ordering relations in color science. The theorem is first described in a special case that proved suitable to color. Then an application of the theorem is described that finds the conditions among reflectance factors in a color atlas such that their chromaticity ordering is illuminant invariant. Finally, an application is described that finds local pathologies in the color gamuts of subtractive and complex‐subtractive colorant systems. These applications should be useful for the design of color atlases.
© 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 310–315, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10080
Correlation between visual and colorimetric scales ranging from threshold to large color difference
Authors: Xu Haisong , Yaguchi Hirohisa , Shioiri Satoshi
Published: September 2002

Psychophysical experiments of color discrimination threshold and suprathreshold color‐difference comparison were carried out with CRT‐generated stimuli using the interleaved staircase and constant stimuli methods, respectively. The experimental results ranged from small (including threshold) to large color difference at the five CIE color centers, which were satisfactorily described by chromaticity ellipses as equal color‐difference contours in the CIELAB space. The comparisons of visual and colorimetric scales in CIELAB unit and threshold unit indicated that the colorimetric magnitudes typically were linear with the visual ones, though with different proportions in individual directions or color centers. In addition, color difference was generally underestimated by the Euclidean distance in the CIELAB space, whereas colorimetric magnitude was perceptually underestimated for threshold unit, implying the present color system is not a really linear uniform space. Furthermore, visual data were used to test the CIELAB‐based color‐difference formulas. In their original forms CIEDE2000 performed a little better than CMC, followed by CIELAB, and with CIE94 showing the worst performance for the combined data set under the viewing condition in this study. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 349–359, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10081
A theorem on geometric rigidity and the derivation of nonlinear plate theory from three‐dimensional elasticity
Authors: Friesecke Gero , James Richard D. , Müller Stefan
Published: September 2002

The energy functional of nonlinear plate theory is a curvature functional for surfaces first proposed on physical grounds by G. Kirchhoff in 1850. We show that it arises as a Γ‐limit of three‐dimensional nonlinear elasticity theory as the thickness of a plate goes to zero. A key ingredient in the proof is a sharp rigidity estimate for maps v : U → ℝn, U ⊂ ℝn. We show that the L2‐distance of ∇v from a single rotation matrix is bounded by a multiple of the L2‐distance from the group SO(n) of all rotations. © 2002 Wiley Periodicals, Inc.
Parallel computation on interval graphs: algorithms and experiments
Authors: Ferreira A. , Guérin Lassous I. , Marcus K. , Rau‐Chaplin A.
Published: September 2002

This paper describes efficient coarse‐grained parallel algorithms and implementations for a suite of interval graph problems. Included are algorithms requiring only a constant number of communication rounds for connected components, maximum weighted clique, and breadth‐first‐search and depth‐first‐search trees, as well as $O(log p)$ communication rounds algorithms for optimization problems such as minimum interval covering, maximum independent set and minimum dominating set, where $p$ is the number of processors in the parallel system. This implies that the number of communication rounds is independent of the problem size. Implementations of these algorithms are evaluated on parallel clusters, using both Fast Ethernet and Myrinet interconnection networks, and on a CRAY T3E parallel multicomputer, with extensive experimental results being presented and analyzed. Copyright © 2002 John Wiley & Sons, Ltd.
A model of transcriptional regulatory networks based on biases in the observed regulation rules
Authors: Harris Stephen E. , Sawhill Bruce K. , Wuensche Andrew , Kauffman Stuart
Published: September 2002

Control rules governing transciption of eukaryotic genes can be modeled as Boolean function, and these rules are strongly biased toward large numbers of “canalizing” inputs. The ensemble of networks with the observed canalizing bias predicts cells are in an ordered regime with convergent flow in transcription state space, a percolating subnetwork of genes fixed on or off an isolated islands of twinkling genes turning on or off, and a near power‐law distribution of cascades of gene activity changes following perturbations. The data suggest that a given cell state or type can be represented as an attractor of transcriptional activity or flow over time. © 2002 Wiley Periodicals, Inc.