bluuebunny/crossref_metadata_2025 huggingface dataset:
Short‐ and Long‐Term Immune Responses of CD‐1 Outbred Mice to the Scrub Typhus DNA Vaccine Candidate: p47Kp
Authors: XU GUANG , CHATTOPADHYAY SUCHISMITA , JIANG JU , CHAN TEIK‐CHYE , CHAO CHIEN‐CHUNG , CHING WEI‐MEI , RICHARDS ALLEN L.
Published: February 2006

Abstract: Orientia tsutsugamushi is an obligate intracellular bacterium that is the causative agent of scrub typhus. To develop an effective vaccine to prevent or ameliorate scrub typhus, knowledge of the protective immune response to O. tsutsugamushi needs to be ascertained. Our laboratory has demonstrated that the DNA vaccine vector pVR1012 carrying the O. tsutsugamushi Karp strain 47‐kDa protein gene (p47Kp) consistently provides outbred mice protection against homologous challenge.
Detection of a Typhus Group Rickettsia in Amblyomma Ticks in the State of Nuevo Leon, Mexico
Authors: MEDINA‐SANCHEZ AARON , BOUYER DONALD H. , ALCANTARA‐RODRIGUEZ VIRGINIA , MAFRA CLAUDIO , ZAVALA‐CASTRO JORGE , WHITWORTH TED , POPOV VSEVOLOD L. , FERNANDEZ‐SALAS ILDEFONSO , WALKER DAVID H.
Published: February 2006

Abstract: The state of Nuevo Leon, Mexico has had outbreaks of typhus group rickettsiosis, most recently recognized in 1997. Evaluation of the sera of 345 patients with a dengue‐like illness revealed that 25.5% had antibodies reactive with typhus group rickettsiae and 16% had antibodies to Rickettsia parkeri. Rickettsiae were detected by PCR and shell‐vial isolations in the field‐collected Amblyomma ticks. Molecular characterization by DNA sequence analysis of the gltA, ompB, and 17‐kDa gene identified the organisms to be R. prowazekii.
Detection of a Non‐Pathogenic Variant of Anaplasma phagocytophilum in Ixodes ricinus from La Rioja, Spain
Authors: PORTILLO A , SANTOS A S , SANTIBÁÑEZ S , PÉREZ‐MARTÍNEZ L , BLANCO J R , IBARRA V , OTEO J A
Published: February 2006

Abstract: Our aim was to identify variants of Anaplasma phagocytophilum 16S rRNA gene sequences among products amplified from Ixodes ricinus collected in La Rioja, Spain. A. phagocytophilum AP‐variant 1, reported as non‐pathogenic, was detected in 12 samples (two adults and ten nymphs). This finding could justify the low incidence of human anaplasmosis in our area, despite the high prevalence of A. phagocytophilum in ticks.
Old and New Human Rickettsiosis in Minas Gerais State, Brazil
Authors: CALIC S B , BARCELLOS‐ROCHA C M , LEITE R C , MAFRA C L , GALVÃO M A M
Published: February 2006

Abstract: The authors describe cases of Brazilian spotted fever (BSF) diagnosed in Minas Gerais state, Brazil, by the Minas Gerais Public Health Laboratory, Ezequiel Dias Foundation from 1995 to 2004. In addition they present three cases of human Rickettsia felis rickettsiosis from Minas Gerais diagnosed in France in 1999, and the first two suspected cases of human monocytic ehrlichiosis (HME) diagnosed in Ezequiel Dias Foundation in 2001. In both cases a differential diagnose was made with BSF.
Genome Analysis ofCoxiella burnetiiSpecies: Insights into Pathogenesis and Evolution and Implications for Biodefense
Authors: SESHADRI REKHA , SAMUEL JAMES
Published: February 2006

Abstract:Coxiella burnetii, the etiological agent of Q fever, is a class B biodefense agent. We are continuing the momentum of discovery generated by the firstCoxiellagenome sequences by extending the breadth of genomics to include four additional heterogeneousC. burnetiistrains. We are also sequencing the genome ofRickettsiella grylli, an intracellular parasite of grasshoppers and the closest known phylogenetic relative to theCoxiellagroup. These data will enable the investigation of fundamental questions aboutCoxiellapathogenicity and virulence as well as broader evolutionary questions about the transition to obligate intracellular life. Specifically, sequence comparisons will permit examination of genetic differences, allowing us to address key questions: What core genes are necessary for an obligate intracellular lifestyle and developmental cycle of the genus? What specific genetic determinants can be linked to virulence properties such as host preference, disease severity, and pathology (i.e., acute vs. chronic disease)? What are the frequencies of mutation and intragenomic recombination, and levels of genome reduction? What specific factors are relevant to colonization and virulence in human hosts (based on comparisons withR. grylli)? From a public health and biodefense perspective, exposure to different strains, either natural or due to illegitimate release, may have different outcomes. With extensive genomic‐level information from diverse strains, investigators can determine effective drug and vaccine targets and design methods to accurately typeCoxiellabased on a subset of genes, opening the way for cost‐effective targeted PCR‐ or antibody‐based tests.
Overcoming Barriers to the Transformation of the Genus Ehrlichia
Authors: LONG S WESLEY , WHITWORTH TED J. , WALKER DAVID H. , YU XUE‐JIE
Published: February 2006

Abstract: While bacterial transformation has evolved since the early 20th century to allow for the genetic manipulation of a variety of microbial agents, rickettsial organisms have proved resistant to such advances until only recently. The Ehrlichia are small, gram‐negative, obligately intracellular bacterial parasites, which belong to the family Anaplasmataceae and cause a variety of infections in human and animal hosts. E. chaffeensis is the causative agent of human monocytotropic ehrlichiosis and is transmitted by Amblyomma americanum, the Lone Star tick. In this work, we describe the first report of successful transformation of a closely related ehrlichial species, the murine monocytotropic species E. muris. Application of these techniques should allow for a wide variety of molecular studies to be performed that were previously impossible. This heralds the beginning of a new era in ehrlichial research.
Innate Immune Tissue Injury and Murine HGA: Tissue Injury in the Murine Model of Granulocytic Anaplasmosis Relates to Host Innate Immune Response and Not Pathogen Load
Authors: SCORPIO DIANA G. , von LOEWENICH FRIEDERIKE D. , BOGDAN CHRISTIAN , DUMLER J STEPHEN
Published: February 2006

Abstract: Anaplasma phagocytophilum is an obligate intracellular tick‐borne bacterium that propagates within neutrophils and causes human and animal granulocytic anaplasmosis (HGA). In the murine model of HGA, host immune response plays a more important role in histopathologic lesions than does pathogen load. We examined the role of CYBB, NOS2, and TNFα as effectors of innate immune‐related injury. Our hypothesis is that the innate immune response to A. phagocytophilum results in inflammatory histopathology, but does not control the pathogen.
Zinc transport activity of Fear of Intimacy is essential for proper gonad morphogenesis and DE-cadherin expression
Authors: Mathews Wendy R. , Ong Daniel , Milutinovich Allison B. , Van Doren Mark
Published: February 2006

Embryonic gonad formation involves intimate contact between germ cells and specialized somatic cells along with the complex morphogenetic movements necessary to create proper gonad architecture. Previously, we have shown that gonad formation in Drosophila requires the homophilic cell-adhesion molecule Drosophila E-cadherin (DE-cadherin), and also Fear of Intimacy (FOI), which is required for stable accumulation of DE-cadherin protein in the gonad. Here, we present an in vivo structure-function analysis of FOI that strongly indicates that zinc transport activity of FOI is essential for gonad development. Mutant forms of FOI that are defective for zinc transport also fail to rescue morphogenesis and DE-cadherin expression in the gonad. We further show that expression of DE-cadherin in the gonad is regulated post-transcriptionally and that foi affects this post-transcriptional control. Expression of DE-cadherin from a ubiquitous(tubulin) promoter still results in gonad-specific accumulation of DE-cadherin, which is strongly reduced in foi mutants. This work indicates that zinc is a crucial regulator of developmental processes and can affect DE-cadherin expression on multiple levels.
The proneural geneascl1ais required for endocrine differentiation and cell survival in the zebrafish adenohypophysis
Authors: Pogoda Hans-Martin , von der Hardt Sophia , Herzog Wiebke , Kramer Carina , Schwarz Heinz , Hammerschmidt Matthias
Published: February 2006

Mammalian basic helix-loop-helix proteins of the achaete-scutefamily are proneural factors that, in addition to the central nervous system,are required for the differentiation of peripheral neurons and sensory cells,derivatives of the neural crest and placodal ectoderm. Here, in identifying the molecular nature of the pia mutation, we investigate the role of the zebrafish achaete-scute homologue ascl1a during development of the adenohypophysis, an endocrine derivative of the placodal ectoderm. Similar to mutants deficient in Fgf3 signaling from the adjacent ventral diencepahalon, pia mutants display failure of endocrine differentiation of all adenohypophyseal cell types. Shortly after the failed first phase of cell differentiation, the adenohypophysis of piamutants displays a transient phase of cell death, which affects most, but not all adenohypophyseal cells. Surviving cells form a smaller pituitary rudiment,lack expression of specific adenohypophyseal marker genes (pit1,neurod), while expressing others (lim3, pitx3), and display an ultrastructure reminiscent of precursor cells. During normal development, ascl1a is expressed in the adenohypophysis and the adjacent diencephalon, the source of Fgf3 signals. However, chimera analyses show that ascl1a is required cell-autonomously in adenohypophyseal cells themselves. In fgf3 mutants, adenohypophyseal expression of ascl1a is absent, while implantation of Fgf3-soaked beads into pia mutants enhances ascl1a, but fails to rescue pit1 expression. Together, this suggests that Ascl1a might act downstream of diencephalic Fgf3 signaling to mediate some of the effects of Fgf3 on the developing adenohypophysis.
A role for Sec8 in oligodendrocyte morphological differentiation
Authors: Anitei Mihaela , Ifrim Marius , Ewart Marie-Ann , Cowan Ann E. , Carson John H. , Bansal Rashmi , Pfeiffer Steven E.
Published: February 2006

In the central nervous system, oligodendrocytes synthesize vast amounts of myelin, a multilamellar membrane wrapped around axons that dramatically enhances nerve transmission. A complex apparatus appears to coordinate trafficking of proteins and lipids during myelin synthesis, but the molecular interactions involved are not well understood. We demonstrate that oligodendrocytes express several key molecules necessary for the targeting of transport vesicles to areas of rapid membrane growth, including the exocyst components Sec8 and Sec6 and the multidomain scaffolding proteins CASK and Mint1. Sec8 overexpression significantly promotes oligodendrocyte morphological differentiation and myelin-like membrane formation in vitro; conversely, siRNA-mediated interference with Sec8 expression inhibits this process, and anti-Sec8 antibody induces a reduction in oligodendrocyte areas. In addition, Sec8 colocalizes, coimmunoprecipitates and cofractionates with the major myelin protein OSP/Claudin11 and with CASK in oligodendrocytes. These results suggest that Sec8 plays a central role in oligodendrocyte membrane formation by regulating the recruitment of vesicles that transport myelin proteins such as OSP/Claudin11 to sites of membrane growth.
PKBα is required for adipose differentiation of mouse embryonic fibroblasts
Authors: Baudry Anne , Yang Zhong-Zhou , Hemmings Brian A.
Published: February 2006

Protein kinase Bα (PKBα) is a key regulator of metabolism, proliferation and differentiation. We have explored the role of PKBα in adipogenesis using wild-type and PKBα-knockout mouse embryonic fibroblasts (MEFs) and show that lack of PKBα prevents MEF differentiation into adipocytes. Expression of ectopic PKBα in PKBα-deficient cells restores adipogenesis. We identified 80 genes whose expression was upregulated in wild-type MEFs during adipogenesis but whose expression was significantly reduced in PKBα-deficient MEFs under the same conditions. Significantly, the regulator of adipogenesis Krüppel-like transcription factor 15 gene expression was downregulated in PKBα-deficient MEFs but could be restored by expressing an active PKBα in the deficient cells. The level of lipocalin 2, renin 1 and receptor-activity-modifying protein 3 genes expressed by adipose cells was also decreased in PKBα-deficient MEFs, and are inhibited by LY294002 treatment during early adipocyte differentiation of 3T3-L1 cells. The results underscore an essential role for PKBα in the transcriptional program required for adipogenesis.
Characterization of a neural-specific splicing form of the human neuregulin 3 gene involved in oligodendrocyte survival
Authors: Carteron Christelle , Ferrer-Montiel Antonio , Cabedo Hugo
Published: February 2006

Neuregulins are a family of genes involved in key aspects of neural biology. Neuregulins 1, 2 and 3 (NRG1, NRG2 and NRG3) are expressed in the mammalian nervous system. It is well established that NRG1, with fifteen different splicing forms, is central for brain development and function. However, the biological relevance of NRG2 and NRG3 remains elusive. Here, we report the identification of a new isoform of NRG3 that is specifically expressed in the human embryonic central nervous system. Sequence alignment with the human genome suggests that this transcript is produced by alternative promoter usage. The encoded polypeptide is a type-I-glycosylated plasma membrane protein, which is shed into the extracellular space where it activates erbB4, a pivotal receptor for brain development. In addition, we show that the protein has a signal sequence that is cleaved after membrane insertion. Proteasome inhibition with Lactacystin enhances the expression of the protein, whereas impairment of ubiquitylation in the conditional mutant cell line ts20 protects the protein from degradation. These observations imply that the ubiquitin/proteasome pathway regulates biogenesis of the protein. We also show that recombinant neuregulin 3 acts as an oligodendrocyte survival factor by activating the phosphoinositide 3-kinase signalling pathway. Therefore, we report a new post-translationally regulated isoform of neuregulin 3 expressed in the developing human central nervous system with a role in oligodendrocyte survival.
Silencing of the hydra serine protease inhibitorKazal1gene mimics the humanSPINK1pancreatic phenotype
Authors: Chera Simona , de Rosa Renaud , Miljkovic-Licina Marijana , Dobretz Kevin , Ghila Luiza , Kaloulis Kostas , Galliot Brigitte
Published: February 2006

In hydra, the endodermal epithelial cells carry out the digestive function together with the gland cells that produce zymogens and express the evolutionarily conserved gene Kazal1. To assess the hydra Kazal1 function, we silenced gene expression through double-stranded RNA feeding. A progressive Kazal1 silencing affected homeostatic conditions as evidenced by the low budding rate and the induced animal death. Concomitantly, a dramatic disorganization followed by a massive death of gland cells was observed, whereas the cytoplasm of digestive cells became highly vacuolated. The presence of mitochondria and late endosomes within those vacuoles assigned them as autophagosomes. The enhanced Kazal1 expression in regenerating tips was strongly diminished in Kazal1(–) hydra, and the amputation stress led to an immediate disorganization of the gland cells, vacuolization of the digestive cells and death after prolonged silencing. This first cellular phenotype resulting from a gene knock-down in cnidarians suggests that the Kazal1 serine-protease-inhibitor activity is required to prevent excessive autophagy in intact hydra and to exert a cytoprotective function to survive the amputation stress. Interestingly, these functions parallel the pancreatic autophagy phenotype observed upon mutation within the Kazal domain of the SPINK1 and SPINK3 genes in human and mice, respectively.
Acidic clusters target transmembrane proteins to the contractile vacuole inDictyosteliumcells
Authors: Mercanti Valentina , Blanc Cédric , Lefkir Yaya , Cosson Pierre , Letourneur François
Published: February 2006

The mechanisms responsible for the targeting of transmembrane integral proteins to the contractile vacuole (CV) network in Dictyostelium discoideum are unknown. Here we show that the transfer of the cytoplasmic domain of a CV-resident protein (Rh50) to a reporter transmembrane protein (CsA) is sufficient to address the chimera (CsA-Rh50) to the CV. We identified two clusters of acidic residues responsible for this targeting, and these motifs interacted with the γ-adaptin AP-1 subunit in a yeast protein-protein interaction assay. For the first time we report the existence of an indirect transport pathway from the plasma membrane to the CV via endosomes. Upon internalization, the small fraction of CsA-Rh50 present at the cell surface was first concentrated in endosomes distinct from early and late p80-positive endosomes and then slowly transported to the CV. Together our results suggest the existence of an AP-1-dependent selective transport to the contractile vacuole in Dictyostelium.
An in vivo study of exocytosis of cement proteins from barnacle Balanus improvisus (D.) cyprid larva
Authors: Ödling Kristin , Albertsson Christian , Russell James T. , Mårtensson Lena G. E.
Published: February 2006

Barnacles, like many marine invertebrates, cause serious biofouling to marine industrial constructions and hulls of vessels as they attach themselves to such surfaces. Precise biochemical understanding of the underwater adhesion to surfaces requires a detailed characterization of the biology of the control of barnacle cement secretion and the proteins that make up the cement. In this study, we have investigated cement secretion by cyprid larvae of Balanus improvisus (D.) and the morphology of their cement glands. We studied the cement protein organization within cement granules and categorized the granules into four different types according to their size and morphology,before and after stimulation of secretion. In addition, we followed the exocytotic process of cement secretion in vivo and discovered that granules undergo a dramatic swelling during secretion. Such swelling might be due to an increased osmotic activity of granule contents, following a process of hydration. We hypothesize that this hydration is essential for exocytotic secretion and conclude that cement protein exocytosis is a more complex process than previously thought and is similar to exocytotic secretion in vertebrate systems, such as histamine secretion from mast cells and exocrine secretion in the salivary gland and the pancreas.
Cutting corners: the dynamics of turning behaviors in two primate species
Authors: Demes Brigitte , Carlson Kristian J. , Franz Theresa M.
Published: February 2006

In an attempt to characterize more fully the variation in substrate reaction forces in the locomotor repertoire of primates, we recorded the forces involved in directional changes for two species. These are the first records of turning forces for vertebrate quadrupeds, much less primates. Three ring-tailed lemurs and two patas monkeys performed turns of approximately 30° as they crossed a force platform. The ring-tailed lemurs also turned on a horizontal branch-like support with a segment attached to the force transducer. Mediolateral forces of up to 40% body weight were recorded. These are considerably higher than during linear locomotion. Pivot limbs in ground turns and turns on the branch differed in the lemurs, suggesting that substrate influences turning strategies. Limbs encountered both medial and lateral reaction forces, and as a result, they may be exposed to variable bending regimes in the frontal plane. The stereotypy in bending regimes suggested by in vivo bone strain studies, therefore, may characterize linear locomotion only. The lemurs showed hindlimb dominance in turns, both in terms of frequency used as well as force magnitude (hindlimb steering). Hindlimb dominance in weight support characterizes both species (and primates in general), but it is more pronounced in the lemurs. In the patas monkeys,forces were more evenly distributed among the two pairs of limbs. The mediolateral turning forces therefore seem to track the amount of weight to be shifted sideways. Overall variance in mediolateral forces was greater in the arboreal and versatile lemurs than in the terrestrial and cursorial patas monkeys.
Crepuscular and nocturnal illumination and its effects on color perception by the nocturnal hawkmoth Deilephila elpenor
Authors: Johnsen Sönke , Kelber Almut , Warrant Eric , Sweeney Alison M. , Widder Edith A. , Lee Raymond L. , Hernández-Andrés Javier
Published: February 2006

Recent studies have shown that certain nocturnal insect and vertebrate species have true color vision under nocturnal illumination. Thus, their vision is potentially affected by changes in the spectral quality of twilight and nocturnal illumination, due to the presence or absence of the moon,artificial light pollution and other factors. We investigated this in the following manner. First we measured the spectral irradiance (from 300 to 700 nm) during the day, sunset, twilight, full moon, new moon, and in the presence of high levels of light pollution. The spectra were then converted to both human-based chromaticities and to relative quantum catches for the nocturnal hawkmoth Deilephila elpenor, which has color vision. The reflectance spectra of various flowers and leaves and the red hindwings of D. elpenor were also converted to chromaticities and relative quantum catches. Finally, the achromatic and chromatic contrasts (with and without von Kries color constancy) of the flowers and hindwings against a leaf background were determined under the various lighting environments. The twilight and nocturnal illuminants were substantially different from each other, resulting in significantly different contrasts. The addition of von Kries color constancy significantly reduced the effect of changing illuminants on chromatic contrast, suggesting that, even in this light-limited environment,the ability of color vision to provide reliable signals under changing illuminants may offset the concurrent threefold decrease in sensitivity and spatial resolution. Given this, color vision may be more common in crepuscular and nocturnal species than previously considered.
Cardiovascular and behavioural changes during water absorption in toads, Bufo alvarius and Bufo marinus
Authors: Viborg Arne L. , Wang Tobias , Hillyard Stanley D.
Published: February 2006

Blood cell flux (BCF) in the pelvic skin of Bufo marinus was lower than Bufo alvarius when toads rehydrated from deionised water (DI) or 50 mmol l–1 NaCl (NaCl). Despite the lower BCF in B. marinus, water absorption was not different between the species when toads rehydrated from DI or NaCl. When fluid contact was limited to the pelvic skin, water uptake from NaCl was lower than from DI, but became greater than uptake from DI as the immersion level increased. Hydrophobic beeswax coating the lateral sides reduced absorption from NaCl but not from DI. Toads settled into water absorption response posture well after maximal BCF was attained in both DI and NaCl, indicating that the behavioural response requires neural integration beyond the increase in BCF. Water exposure increased BCF in hydrated B. alvarius with empty bladders but not in those with stored bladder water. Hydrated B. marinus with an empty bladder did not increase BCF when given water. Handling stress depressed BCF but increased central arterial flow (CAF), measured using a flow probe around the dorsal aorta. In undisturbed toads, CAF increased with the same time course as BCF while heart rate remained relatively constant, suggesting redistribution of blood flow.
Respiration by buried echidnas Tachyglossus aculeatus
Authors: Waugh Courtney A. , Grigg Gordon C. , Booth David T. , Beard Lyn A.
Published: February 2006

Short-beaked echidnas have an impressive ability to submerge completely into soil or sand and remain there, cryptic, for long periods. This poses questions about how they manage their respiration, cut off from a free flow of gases. We measured the gradient in oxygen partial pressure(PO2) away from the snouts of buried echidnas and oxygen consumption(V̇O2) in five individuals under similar conditions, in two substrates with different air-filled porosities (fa). A theoretical diffusion model indicated that diffusion alone was insufficient to account for the flux of oxygen required to meet measured rates of V̇O2. However, it was noticed that echidnas often showed periodic movements of the anterior part of the body, as if such movements were a deliberate effort to flush the tidal air space surrounding their nostrils. These `flushing movements' were subsequently found to temporarily increase the levels of interstitial oxygen in the soil around the head region. Flushing movements were more frequent while V̇O2 was higher during the burrowing process, and also in substrate with lower fa. We conclude that oxygen supply to buried echidnas is maintained by diffusion through the soil augmented by periodic flushing movements, which ventilate the tidal airspace that surrounds the nostrils.
The effects of depth, temperature and food ingestion on the foraging energetics of a diving endotherm, the double-crested cormorant(Phalacrocorax auritus)
Authors: Enstipp Manfred R. , Grémillet David , Jones David R.
Published: February 2006

Avian divers are confronted with a number of physiological challenges when foraging in cold water, especially at depth. Besides the obvious constraint imposed by the necessity to return to the surface for gas exchange, cold water temperatures and a reduction in body insulation due to the increase in pressure with dive depth will elevate the energetic costs of foraging in these endotherm divers. The complex effect that depth has on the diving energetics of aquatic birds has largely been ignored. To date, no study has assessed the impact of depth on diving energetics over a significant depth range, naturally encountered by the diver. We used open-circuit respirometry to study the energetic requirements of a foot-propelled pursuit diver, the double-crested cormorant (Phalacrocorax auritus albociliatus), when diving in a shallow (1 m) and deep (10 m) dive tank and when resting in air and water. We also investigated the modifying effects of air or water temperature and feeding status on the costs associated with diving and resting. Of all factors investigated, dive depth exercised the strongest influence on diving metabolic rate. Diving to 10 m depth increased metabolic rate on average by 22% when compared with shallow diving. Declining temperatures in air and water significantly elevated metabolic rate of cormorants resting in air and water as well as during diving. Feeding before resting in water or diving increased metabolic rate by 5–8% for at least 2 h. Cormorants maintained an elevated stomach temperature (>42°C) when resting in water and during diving, even at cold temperatures. The elevated dive costs during deep diving,when compared with shallow diving, are most likely a consequence of the increased thermoregulatory costs associated with a greater heat loss to the water at depth. Nevertheless, our study shows that dive costs in double-crested cormorants are similar to those of other foot-propelled avian divers.
Giant liposomes as delivery system for ecophysiological studies in copepods
Authors: Buttino Isabella , De Rosa Giuseppe , Carotenuto Ylenia , Ianora Adrianna , Fontana Angelo , Quaglia Fabiana , La Rotonda Maria Immacolata , Miralto Antonio
Published: February 2006

Giant liposomes are proposed as a potential delivery system in marine copepods, the dominant constituent of the zooplankton. Liposomes were prepared in the same size range as the food ingested by copepods (mean diameter of about 7 μm). The encapsulation of a hydrophilic and high molecular mass fluorescent compound, fluorescein isothiocyanate-dextran (FitcDx), within the liposomes provided a means of verifying copepod ingestion when viewed with the confocal laser-scanning microscope. Females of the calanoid copepod Temora stylifera were fed with FitcDx-encapsulated liposomes alone or mixed with the dinoflagellate alga Prorocentrum minimum. Control copepods were incubated with the P. minimum diet alone. Egg production rates,percentage egg-hatching success and number of faecal pellets produced were evaluated after 24 h and 48 h of feeding. Epifluorescence of copepod gut and faecal pellets indicated that the liposomes were actively ingested by T. stylifera in both experimental food conditions, with or without the dinoflagellate diet. Ingestion rates calculated using 3H-labelled liposomes indicated that females ingested more liposomes when P. minimum was added to the solution (16% vs 7.6% of uptake). When liposomes were supplied together with the algal diet, egg production rate,egg-hatching success and faecal pellet production were as high as those observed for the control diet. By contrary, egg production and hatching success were very low with a diet of liposomes alone and faecal pellet production was similar to that recorded in starved females. This results suggest that liposomes alone did not add any nutritive value to the diet,making them a good candidate as inert carriers to study the nutrient requirements or biological activity of different compounds. In particular,such liposomes are proposed as carriers for diatom-derived polyunsaturated aldehydes, which are known to impair copepod embryo viability. Other potential applications of liposomes as a delivery system of drugs and nutrients in copepod mass cultivation, or as carriers of pollutants to study copepod physiology in ecotoxicological experiments, are also discussed.
Taste discrimination in conditioned taste aversion of the pond snailLymnaea stagnalis
Authors: Sugai Rio , Shiga Hatsuki , Azami Sachiyo , Watanabe Takayuki , Sadamoto Hisayo , Fujito Yutaka , Lukowiak Ken , Ito Etsuro
Published: February 2006

Conditioned taste aversion (CTA) in the pond snail Lymnaea stagnalis has been widely used as a model for gaining an understanding of the molecular and behavioral mechanisms underlying learning and memory. At the behavioral level, however, it is still unclear how taste discrimination and CTA interact. We thus examined how CTA to one taste affected the feeding response induced by another appetitive food stimulus. We first demonstrated that snails have the capacity to recognize sucrose and carrot juice as distinct appetitive stimuli. We then found that snails can become conditioned(i.e. CTA) to avoid one of the stimuli and not the other. These results show that snails can distinguish between appetitive stimuli during CTA, suggesting that taste discrimination is processed upstream of the site where memory consolidation in the snail brain occurs. Moreover, we examined second-order conditioning with two appetitive stimuli and one aversive stimulus. Snails acquired second-order conditioning and were still able to distinguish between the different stimuli. Finally, we repeatedly presented the conditional stimulus alone to the conditioned snails, but this procedure did not extinguish the long-term memory of CTA in the snails. Taken together, our data suggest that CTA causes specific, irreversible and rigid changes from appetitive stimuli to aversive ones in the conditioning procedure.
Fuel use during glycogenesis in rainbow trout (Oncorhynchus mykissWalbaum) white muscle studiedin vitro
Authors: Kam Jennifer C. , Milligan C. Louise
Published: February 2006

The purpose of this study was to examine fuel used during muscle glycogenesis in rainbow trout Oncorhynchus mykiss using an in vitro muscle slice preparation to test the hypothesis that intracellular lactate is the major glycogenic substrate and the muscle relies upon extracellular substrates for oxidation. Fish were exhaustively exercised to reduce muscle glycogen content, muscle slices were taken from exhausted fish and incubated for 1 h in medium containing various substrates at physiological concentrations. 14C-labeled lactate, glycerol or palmitate was added and 14C incorporation into muscle glycogen and/or CO2 was measured. Lactate clearance in the absence of net glycogenesis suggests that when suitable oxidizable extracellular substrates were lacking, intracellular lactate was oxidized. Only muscle incubated in lactate, glycerol or palmitate synthesized glycogen, with the greatest synthesis in muscle incubated in lactate plus glycerol. The major fate of these extracellular substrates was oxidative, with lactate oxidized at rates 10 times that of palmitate and 100 times that of glycerol. Neither extracellular lactate nor glycerol contributed significantly to glycogenesis,with lactate carbon contributing less than 0.1% of the total glycogen synthesized, and glycerol less than 0.01%. There was 100 times more extracellular lactate-carbon incorporated into CO2 than into glycogen. In the presence of extracellular lactate, palmitate or glycerol,intracellular lactate was spared an oxidative fate, allowing it to serve as the primary substrate for in situ glycogenesis, with oxidation of extracellular substrates driving ATP synthesis. The primary fate of extracellular lactate is clearly oxidative, while that of intracellular,glycolytically derived lactate is glycogenic, which suggests intracellular compartmentation of lactate metabolism.
Distribution, activity and evidence for the release of an anti-diuretic peptide in the kissing bug Rhodnius prolixus
Authors: Paluzzi Jean-Paul , Orchard Ian
Published: February 2006

In the haematophagous insect Rhodnius prolixus, diuresis is accomplished through the combined actions of peptidergic diuretic hormones and 5-HT released from neurohaemal sites on the abdominal nerves. Preliminary work on anti-diuresis in this blood-feeder, previously believed to occur through a decrease in the levels of the diuretic factors, indicates that an anti-diuretic hormone, with properties similar to CAP2b (pELYAFPRVamide;recently renamed Mas-CAPA-1), might also be present in R. prolixus. Here, we present evidence from immunohistochemical analysis that suggests a PRXamide-like neuropeptide may be released from the abdominal neurohaemal sites beginning 3–4 h following feeding; a time that coincides with the cessation of diuresis. We also show evidence for an endogenous factor,isolated from the central nervous system using reversed-phase high performance liquid chromatography, which mimics the effects of Mas-CAPA-1. Specifically,this endogenous anti-diuretic factor inhibits rates of 5-HT-stimulated secretion in a dose-dependent manner and elevates intracellular cGMP levels of Malpighian tubules stimulated with 5-HT.
Quetiapine for Insomnia Associated with Refractory Depression Exacerbated by Phenelzine
Authors: Sokolski Kenneth N , Brown Brenda J
Published: February 2006

Objective:

To report the successful treatment of phenelzine-associated insomnia with low-dose quetiapine in a patient with refractory depression.

Case Summary:

A 42-year-old white man with severe major depression unresponsive to selective serotonin-reuptake inhibitors, bupropion, and tricyclic antidepressants improved following treatment with the monoamine oxidase inhibitor (MAOI) phenelzine. Insomnia, present to a moderate degree prior to antidepressant therapy, worsened markedly following phenelzine treatment and failed to respond to diphenhydramine, temazepam, triazolam, clonazepam, Zolpidem, or trazodone given at high therapeutic doses. Sleep disturbance resolved with low-dose (50 mg) adjunctive quetiapine, with no adverse effects.

Discussion:

Major depression refractory to standard therapy is a common and serious condition. Some cases respond to MAOIs; however, orthostatic hypotension and insomnia frequently occur. Potentially serious MAOI interactions with psychotropic drugs have raised concerns about combining these agents. In this case, a failure of a number of other medications known to treat MAOI-associated insomnia safely prompted a trial of quetiapine. Despite the possibility that enhanced serotonergic activity might have resulted in serotonin syndrome, no adverse interactions between phenelzine and quetiapine were noted. The use of low-dose, once-daily quetiapine, along with its unique binding properties, may account for its increased safety in combination with phenelzine.

Conclusions:

This case illustrates that low-dose quetiapine may be an alternative treatment for phenelzine-associated insomnia. Further case reports are needed to establish the safety and effectiveness of combining these agents.
Infectious Diseases: Tolerance of Vancomycin for Surgical Prophylaxis in Patients Undergoing Cardiac Surgery and Incidence of Vancomycin-Resistant Enterococcus Colonization
Authors: Kachroo Sumesh , Dao Thanh , Zabaneh Firas , Reiter Margaret , LaRocco Mark T , Gentry Layne O , Garey Kevin W
Published: February 2006

Background:

In 2001, vancomycin replaced cefuroxime for antibiotic prophylaxis in patients undergoing cardiac surgery at our institution due to high rates of surgical site infections caused by methicillin-resistant Staphylococcus spp. However, few data supported the use of vancomycin for surgical prophylaxis.

Objective:

To determine the tolerance of vancomycin for antibiotic prophylaxis and incidence of vancomycin-resistant Enterococcus (VRE) in cardiac surgery patients.

Methods:

In 2 separate studies, we assessed the adverse effects in patients given perioperative vancomycin (study 1) and the incidence of VRE in patients given perioperative vancomycin (study 2). Study 1 was a prospective cohort study of patients undergoing coronary artery bypass graft (CABG) or valve replacement surgery given vancomycin (1 dose preoperatively/2 doses postoperatively) for antibiotic prophylaxis between October 2003 and December 2004. Patients were assessed for tolerance to the antibiotic regimen. In study 2, cardiac surgery patients receiving perioperative vancomycin were screened for VRE before therapy and at day 7 of hospitalization. VRE was detected using standard microbiologic procedures.

Results:

In study 1, 1161 patients (CABG = 75%; valve = 19%; both = 6%) were evaluated. All patients but one (99.9%) were prescribed preoperative vancomycin. Therapy was changed for 34 (2.9%) patients, of which 20 changes were due to physician preference for another antibiotic. The only toxicity that required a change in the vancomycin regimen was red man's syndrome, which was experienced by 9 (0.8%) patients. Four patients did not receive a second postoperative dose due to prior renal insufficiency. Patients were most commonly switched to cefuroxime (n = 26), linezolid (n = 2), cefepime (n = 2), gatifloxacin, cefazolin, levofloxacin, or ceftriaxone (n = 1, each). In study 2, 100 patients were screened for the emergence of VRE colonization. No patient was VRE positive at baseline and 4 (4%) were positive at day 7.

Conclusions:

Surgical antibiotic prophylaxis with vancomycin was reasonably well tolerated in CABG and valve replacement surgery, with a 4% incidence of VRE colonization.
Frequency of Serum Creatinine Monitoring During Allopurinol Therapy in Ambulatory Patients
Authors: Raebel Marsha A , McClure David L , Simon Steven R , Chan K Arnold , Feldstein Adrianne C , Gunter Margaret J , Lafata Jennifer Elston , Harrold Leslie , Nelson Winnie W , Platt Richard
Published: February 2006

Background:

Allopurinol dosage reduction is recommended in patients with renal dysfunction because drug toxicity risk is increased. Little information is available about serum creatinine (SCr) monitoring in ambulatory patients taking allopurinol.

Objective:

To evaluate SCr monitoring among patients prescribed allopurinol, identify associated factors, and evaluate administrative data in assessing monitoring.

Methods:

Information for this retrospective cohort study was drawn from a dataset of 2 020 037 individuals; approximately 200 000 members from each of 10 organizations. Study patients had received at least one year of ongoing allopurinol prescription dispensings. Patient variables analyzed included age, gender, chronic diseases, outpatient visits, hospitalizations, gout diagnosis, and SCr monitoring. A random sample of medical records was reviewed to assess the accuracy of the automated data. Statistical analysis included descriptive and logistic regression techniques.

Results:

Overall, 1139 (26%) of 4357 patients did not have SCr monitoring. For individuals without recent hospitalization, factors protective against lack of monitoring were increasing age (OR 0.77 per 10 y; 95% CI 0.74 to 0.79), more chronic diseases (OR 0.81; 95% CI 0.78 to 0.83), more outpatient visits (OR 0.87 per 5 visits; 95% CI 0.83 to 0.91), and gout diagnosis (OR 0.74; 95% CI 0.65 to 0.85). The sensitivity and specificity of administrative data compared with medical records for SCr monitoring were 92% and 65%, respectively.

Conclusions:

More than one-fourth of patients dispensed allopurinol did not have SCr monitoring during one year of therapy. Lack of monitoring and lack of subsequent possible dosage adjustment put patients at increased risk of allopurinol toxicity.
Rapid Topographical Plasticity of the Visuomotor Spatial Transformation
Authors: Fernandez-Ruiz Juan , Diaz Rosalinda , Moreno-Briseño Pablo , Campos-Romo Aurelio , Ojeda Rafael
Published: February 2006

Information about the world is often encoded in the brain as topographic maps. These internal representations are not always static but can have a dynamic nature, allowing for constant adjustments that depend on factors like experience or injury. Recently, it has been shown that areas involved in visuomotor transformations also show topographical organization. These findings suggest that it could be possible to observe plastic modifications in specific parts of the representation in response to a local perturbation that affects only a part of the space that is represented. Here, we tested this hypothesis using an adaptation paradigm with hemiprisms. Our results suggest that, initially, the system tries to modify the visuomotor transformation in the whole spatial representation; however, if feedback is available from both hemifields, the system can perform specific regional topographical realignments. The results also suggest that access to the rearranged visuomotor transformation is independent of eye position, in contrast with previous studies that found a kind of conditional learning. Also, whereas prism adaptation experiments using ballistic movements do not show intermanual transfer of learning, the topographical modification found here is available to both hands. These results provide strong evidence for rapid topographical plasticity that can modify space transformations between two different modalities.
Matrix Metalloproteinase-9 Is Required for Hippocampal Late-Phase Long-Term Potentiation and Memory
Authors: Nagy Vanja , Bozdagi Ozlem , Matynia Anna , Balcerzyk Marcin , Okulski Pawel , Dzwonek Joanna , Costa Rui M. , Silva Alcino J. , Kaczmarek Leszek , Huntley George W.
Published: February 2006

Matrix metalloproteinases (MMPs) are extracellular proteases that have well recognized roles in cell signaling and remodeling in many tissues. In the brain, their activation and function are customarily associated with injury or pathology. Here, we demonstrate a novel role for MMP-9 in hippocampal synaptic physiology, plasticity, and memory. MMP-9 protein levels and proteolytic activity are rapidly increased by stimuli that induce late-phase long-term potentiation (L-LTP) in area CA1. Such regulation requires NMDA receptors and protein synthesis. Blockade of MMP-9 pharmacologically prevents induction of L-LTP selectively; MMP-9 plays no role in, nor is regulated during, other forms of short-term synaptic potentiation or long-lasting synaptic depression. Similarly, in slices from MMP-9 null-mutant mice, hippocampal LTP, but not long-term depression, is impaired in magnitude and duration; adding recombinant active MMP-9 to null-mutant slices restores the magnitude and duration of LTP to wild-type levels. Activated MMP-9 localizes in part to synapses and modulates hippocampal synaptic physiology through integrin receptors, because integrin function-blocking reagents prevent an MMP-9-mediated potentiation of synaptic signal strength. The fundamental importance of MMP-9 function in modulating hippocampal synaptic physiology and plasticity is underscored by behavioral impairments in hippocampal-dependent memory displayed by MMP-9 null-mutant mice. Together, these data reveal new functions for MMPs in synaptic and behavioral plasticity.
Alcohol Potently Modulates Climbing Fiber→Purkinje Neuron Synapses: Role of Metabotropic Glutamate Receptors
Authors: Carta Mario , Mameli Manuel , Valenzuela C. Fernando
Published: February 2006

Consumption of alcoholic beverages produces alterations in motor coordination and equilibrium that are responsible for millions of accidental deaths. Studies indicate that ethanol produces these alterations by affecting the cerebellum, a brain region involved in the control of motor systems. Purkinje neurons of the cerebellar cortex have been shown to be particularly important targets of ethanol. However, its mechanism of action at these neurons is poorly understood. We hypothesized that ethanol could modulate Purkinje neuron function by altering the excitatory input provided by the climbing fiber from the inferior olive, which evokes a powerful all-or-none response denoted as the complex spike. To test this hypothesis, we performed whole-cell patch-clamp electrophysiological and Ca2+imaging experiments in acute slices from rat cerebella. We found that ethanol potently inhibits the late phase of the complex spike and that this effect is the result of inhibition of type-1 metabotropic glutamate receptor-dependent responses at the postsynaptic level. Moreover, ethanol inhibited climbing fiber long-term depression, a form of synaptic plasticity that also depends on activation of these metabotropic receptors. Our findings identify the climbing fiber→Purkinje neuron synapse as an important target of ethanol in the cerebellar cortex and indicate that ethanol significantly affects cerebellar circuits even at concentrations as low as 10 mm(legal blood alcohol level in the United States is below 0.08 g/dl = 17 mm).
ErbB2 Signaling in Schwann Cells Is Mostly Dispensable for Maintenance of Myelinated Peripheral Nerves and Proliferation of Adult Schwann Cells after Injury
Authors: Atanasoski Suzana , Scherer Steven S. , Sirkowski Erich , Leone Dino , Garratt Alistair N. , Birchmeier Carmen , Suter Ueli
Published: February 2006

Neuregulin/erbB signaling is critically required for survival and proliferation of Schwann cells as well as for establishing correct myelin thickness of peripheral nerves during development. In this study, we investigated whether erbB2 signaling in Schwann cells is also essential for the maintenance of myelinated peripheral nerves and for Schwann cell proliferation and survival after nerve injury. To this end, we used inducible Cre-loxP technology using a PLP-CreERT2 allele to ablate erbB2 in adult Schwann cells. ErbB2 expression was markedly reduced after induction oferbB2gene disruption with no apparent effect on the maintenance of already established myelinated peripheral nerves. In contrast to development, Schwann cell proliferation and survival were not impaired in mutant animals after nerve injury, despite reduced levels of MAPK-P (phosphorylated mitogen-activated protein kinase) and cyclin D1. ErbB1 and erbB4 do not compensate for the loss of erbB2. We conclude that adult Schwann cells do not require major neuregulin signaling through erbB2 for proliferation and survival after nerve injury, in contrast to development and in cell culture.