bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced expression of Harvey ras induced by serum deprivation in cultured astrocytes
Authors: Messina Samantha , Molinaro Gemma , Bruno Valeria , Battaglia Giuseppe , Spinsanti Paola , Di Pardo Alba , Nicoletti Ferdinando , Frati Luigi , Porcellini Antonio
Published: April 2008

Trophic deprivation contributes to astrocyte damage that occurs in acute and chronic neurodegenerative disorders. Unraveling the underlying mechanisms may pave way to novel cytoprotective strategies. Cultured mouse astrocytes responded to trophic deprivation with a large and transient increase in the expression of p21ras, which was secondary to an enhanced formation of reactive oxygen species (ROS) detected by cytofluorimetric analysis after preloading with 2′,7′‐dichlorofluorescein diacetate. The increase in p21ras levels was largely attenuated by the reducing agent, N‐acetylcysteine, which was proven to reduce ROS formation in astrocytes subjected to serum deprivation. We extended the analysis to the Ha‐Ras isoform, which has been implicated in mechanisms of cytotoxicity. We found that serum deprivation enhanced the expression and activity of Ha‐Ras without changing Ha‐Ras mRNA levels. The increase in Ha‐Ras levels was sensitive to the protein synthesis inhibitor, cycloheximide, suggesting that serum deprivation increases translation of preformed Ha‐Ras mRNA. The late decline in Ha‐Ras levels observed after 60 min was prevented by the proteasome inhibitor, MG132, as well as by the selective mitogen‐activated protein kinase (MAPK) inhibitor, PD98059. Serum deprivation led to the activation of the MAPK pathway in cultured astrocytes, as shown by an increase in phosphorylated extracellular signal‐regulated kinase 1/2 levels after 5 and 30 min. Finally, using the siRNA technology, we found that an acute knock‐down of Ha‐Ras was protective against astrocyte damage induced by serum deprivation. We conclude that cultured astrocytes respond to trophic deprivation with an increased expression in Ha‐Ras, which is limited by the concomitant activation of the MAPK pathway, but is nevertheless involved in the pathophysiology of cell damage.
Methamphetamine‐induced neurotoxicity and microglial activation are not mediated by fractalkine receptor signaling
Authors: Thomas David M. , Francescutti‐Verbeem Dina M. , Kuhn Donald M.
Published: April 2008

Methamphetamine (METH) damages dopamine (DA) nerve endings by a process that has been linked to microglial activation but the signaling pathways that mediate this response have not yet been delineated. Cardona et al. [Nat. Neurosci. 9 (2006), 917] recently identified the microglial‐specific fractalkine receptor (CX3CR1) as an important mediator of MPTP‐induced neurodegeneration of DA neurons. Because the CNS damage caused by METH and MPTP is highly selective for the DA neuronal system in mouse models of neurotoxicity, we hypothesized that the CX3CR1 plays a role in METH‐induced neurotoxicity and microglial activation. Mice in which the CX3CR1 gene has been deleted and replaced with a cDNA encoding enhanced green fluorescent protein (eGFP) were treated with METH and examined for striatal neurotoxicity. METH depleted DA, caused microglial activation, and increased body temperature in CX3CR1 knockout mice to the same extent and over the same time course seen in wild‐type controls. The effects of METH in CX3CR1 knockout mice were not gender‐dependent and did not extend beyond the striatum. Striatal microglia expressing eGFP constitutively show morphological changes after METH that are characteristic of activation. This response was restricted to the striatum and contrasted sharply with unresponsive eGFP‐microglia in surrounding brain areas that are not damaged by METH. We conclude from these studies that CX3CR1 signaling does not modulate METH neurotoxicity or microglial activation. Furthermore, it appears that striatal‐resident microglia respond to METH with an activation cascade and then return to a surveying state without undergoing apoptosis or migration.
Detection of Active Butyrate-Degrading Microorganisms in Methanogenic Sludges by RNA-Based Stable Isotope Probing
Authors: Hatamoto Masashi , Imachi Hiroyuki , Yashiro Yuto , Ohashi Akiyoshi , Harada Hideki
Published: April 2008

Butyrate-degrading bacteria in four methanogenic sludges were studied by RNA-based stable isotope probing. Bacterial populations in the
13
C-labeled rRNA fractions were distinct from unlabeled fractions, and
Syntrophaceae
species,
Tepidanaerobacter
sp., and
Clostridium
spp. dominated. These results suggest that diverse microbes were active in butyrate degradation under methanogenic conditions.
The Supernumerary Chromosome of
Nectria haematococca
That Carries Pea-Pathogenicity-Related Genes Also Carries a Trait for Pea Rhizosphere Competitiveness
Authors: Rodriguez-Carres M. , White G. , Tsuchiya D. , Taga M. , VanEtten H. D.
Published: April 2008

Fungi are found in a wide range of environments, and the ecological and host diversity of the fungus
Nectria haematococca
has been shown to be due in part to unique genes on different supernumerary chromosomes. These chromosomes have been called “conditionally dispensable” (CD) since they are not needed for axenic growth but are important for expanding the host range of individual isolates. From a biological perspective, the CD chromosomes can be compared to bacterial plasmids that carry unique genes that can define the habits of these microorganisms. The current study establishes that the
N. haematococca PDA1
-CD chromosome, which contains the genes for pea pathogenicity (
PEP
cluster) on pea roots, also carries a gene(s) for the utilization of homoserine, a compound found in large amounts in pea root exudates. Competition studies demonstrate that an isolate that lacks the
PEP
cluster but carries a portion of the CD chromosome which includes the homoserine utilization (
HUT
) gene(s) is more competitive in the pea rhizosphere than an isolate without the CD chromosome.
Synthesis and Accumulation of Cyanophycin in Transgenic Strains of
Saccharomyces cerevisiae
Authors: Steinle Anna , Oppermann-Sanio Fred Bernd , Reichelt Rudolf , Steinbüchel Alexander
Published: April 2008

Cyanophycin [multi-
l
-arginyl-poly(
l
-aspartic acid) (CGP)] was, for the first time, produced in yeast. As yeasts are very important production organisms in biotechnology, it was determined if CGP can be produced in two different strains of
Saccharomyces cerevisiae
. The episomal vector systems pESC (with the galactose-inducible promoter
GAL1
) and pYEX-BX (with the copper ion-inducible promoter
CUP1
) were chosen to express the cyanophycin synthetase gene from the cyanobacterium
Synechocystis
sp. strain PCC 6308 (
cphA
6308
) in yeast. Expression experiments with transgenic yeasts revealed that the use of the
CUP1
promoter is much more efficient for CGP production than the
GAL1
promoter. As observed by electrophoresis of isolated CGP in sodium dodecyl sulfate-polyacrylamide gels, the yeast strains produced two different types of polymer: the water-soluble and the water-insoluble CGP were observed as major and minor forms of the polymer, respectively. A maximum CGP content of 6.9% (wt/wt) was detected in the cells. High-performance liquid chromatography analysis showed that the isolated polymers consisted mainly of the two amino acids aspartic acid and arginine and that, in addition, a minor amount (2 mol%) of lysine was present. Growth of transgenic yeasts in the presence of 15 mM lysine resulted in an incorporation of up to 10 mol% of lysine into CGP. Anti-CGP antibodies generated against CGP isolated from
Escherichia coli
TOP10 harboring
cphA
6308
reacted with insoluble CGP but not with soluble CGP, if applied in Western or dot blots.
In Vitro Mutagenesis of
Bacillus subtilis
by Using a Modified Tn
7
Transposon with an Outward-Facing Inducible Promoter
Authors: Bordi Christophe , Butcher Bronwyn G. , Shi Qiaojuan , Hachmann Anna-Barbara , Peters Joseph E. , Helmann John D.
Published: April 2008

A Tn
7
donor plasmid, pTn7SX, was constructed for use with the model gram-positive bacterium
Bacillus subtilis
. This new mini-Tn
7
, mTn7SX, contains a spectinomycin resistance cassette and an outward-facing, xylose-inducible promoter, thereby allowing for the regulated expression of genes downstream of the transposon. We demonstrate that mTn7SX inserts are obtained at a high frequency and occur randomly throughout the
B. subtilis
genome. The utility of this system was demonstrated by the selection of mutants with increased resistance to the antibiotic fosfomycin or duramycin.
Free-Living Tube Worm Endosymbionts Found at Deep-Sea Vents
Authors: Harmer Tara L. , Rotjan Randi D. , Nussbaumer Andrea D. , Bright Monika , Ng Andrew W. , DeChaine Eric G. , Cavanaugh Colleen M.
Published: April 2008

Recent evidence suggests that deep-sea vestimentiferan tube worms acquire their endosymbiotic bacteria from the environment each generation; thus, free-living symbionts should exist. Here, free-living tube worm symbiont phylotypes were detected in vent seawater and in biofilms at multiple deep-sea vent habitats by PCR amplification, DNA sequence analysis, and fluorescence in situ hybridization. These findings support environmental transmission as a means of symbiont acquisition for deep-sea tube worms.
Isolation of Fungal Cellobiohydrolase I Genes from Sporocarps and Forest Soils by PCR
Authors: Edwards Ivan P. , Upchurch Rima A. , Zak Donald R.
Published: April 2008

Cellulose is the major component of plant biomass, and microbial cellulose utilization is a key step in the decomposition of plant detritus. Despite this, little is known about the diversity of cellulolytic microbial communities in soil. Fungi are well known for their cellulolytic activity and mediate key functions during the decomposition of plant detritus in terrestrial ecosystems. We developed new oligonucleotide primers for fungal exocellulase genes (cellobiohydrolase,
cbhI
) and used these to isolate distinct
cbhI
homologues from four species of litter-decomposing basidiomycete fungi (
Clitocybe nuda
,
Clitocybe gibba
,
Clitopilus prunulus
, and
Chlorophyllum molybdites
) and two species of ascomycete fungi (
Xylaria polymorpha
and
Sarcoscypha occidentalis
). Evidence for
cbhI
gene families was found in three of the four basidiomycete species. Additionally, we isolated and cloned
cbhI
genes from the forest floor and mineral soil of two upland forests in northern lower Michigan, one dominated by oak (
Quercus velutina
,
Q. alba
) and the other dominated by sugar maple (
Acer saccharum
) and American basswood (
Tilia americana
). Phylogenetic analysis demonstrated that cellobiohydrolase genes recovered from the floor of both forests tended to cluster with
Xylaria
or in one of two unidentified groups, whereas cellobiohydrolase genes recovered from soil tended to cluster with
Trichoderma
,
Alternaria
, Eurotiales, and basidiomycete sequences. The ability to amplify a key fungal gene involved in plant litter decomposition has the potential to unlock the identity and dynamics of the cellulolytic fungal community in situ.
Contributions of the Response Regulators Ssk1p and Skn7p in the Pseudohyphal Development, Stress Adaptation, and Drug Sensitivity of the Opportunistic Yeast
Candida lusitaniae
Authors: Ruprich-Robert Gwenaël , Chapeland-Leclerc Florence , Boisnard Stéphanie , Florent Martine , Bories Gaël , Papon Nicolas
Published: April 2008

We recently characterized the histidine kinase receptor genes of
Candida lusitaniae
. For the present study, we have further investigated the role of
SSK1
and
SKN7
, encoding response regulators. The results of functional analysis of mutants indicated that Ssk1p is involved in osmotolerance and pseudohyphal development, whereas Skn7p appears crucial for oxidative stress adaptation.
Inactivation of
lsr2
Results in a Hypermotile Phenotype in
Mycobacterium smegmatis
Authors: Arora Kriti , Whiteford Danelle C. , Lau-Bonilla Dalia , Davitt Christine M. , Dahl John L.
Published: April 2008

Mycobacterial species are characterized by the presence of lipid-rich, hydrophobic cell envelopes. These cell envelopes contribute to properties such as roughness of colonies, aggregation of cells in liquid culture without detergent, and biofilm formation. We describe here a mutant strain of
Mycobacterium smegmatis
, called DL1215, which demonstrates marked deviations from the above-mentioned phenotypes. DL1215 arose spontaneously from a strain deficient for the stringent response (
M. smegmatis
Δ

rel
Msm

strain) and is not a reversion to a wild-type phenotype. The nature of the spontaneous mutation was a single base-pair deletion in the
lsr2
gene, leading to the formation of a truncated protein product. The DL1215 strain was complicated by having both inactivated

rel
Msm

and
lsr2
genes, and so a single
lsr2
mutant was created to analyze the gene's function. The
lsr2
gene was inactivated in the wild-type
M. smegmatis
mc
2
155 strain by allelic replacement to create strain DL2008. Strain DL2008 shows characteristics unique from those of both the wild-type and Δ

rel
Msm

strains, some of which include a greatly enhanced ability to slide over agar surfaces (referred to here as “hypermotility”), greater resistance to phage infection and to the antibiotic kanamycin, and an inability to form biofilms. Complementation of the DL2008 mutant with a plasmid containing
lsr2
(pLSR2) reverts the strain to the mc
2
155 phenotype. Although these phenotypic differences allude to changes in cell surface lipids, no difference is observed in glycopeptidolipids, polar lipids, apolar lipids, or mycolic acids of the cell wall.
Surface Viscoelasticity of Individual Gram-Negative Bacterial Cells Measured Using Atomic Force Microscopy
Authors: Vadillo-Rodriguez Virginia , Beveridge Terry J. , Dutcher John R.
Published: April 2008

The cell envelope of gram-negative bacteria is responsible for many important biological functions: it plays a structural role, it accommodates the selective transfer of material across the cell wall, it undergoes changes made necessary by growth and division, and it transfers information about the environment into the cell. Thus, an accurate quantification of cell mechanical properties is required not only to understand physiological processes but also to help elucidate the relationship between cell surface structure and function. We have used a novel, atomic force microscopy (AFM)-based approach to probe the mechanical properties of single bacterial cells by applying a constant compressive force to the cell under fluid conditions while measuring the time-dependent displacement (creep) of the AFM tip due to the viscoelastic properties of the cell. For these experiments, we chose a representative gram-negative bacterium,
Pseudomonas aeruginosa
PAO1, and we used regular V-shaped AFM cantilevers with pyramid-shaped and colloidal tips. We find that the cell response is well described by a three-element mechanical model which describes an effective cell spring constant,
k
1
, and an effective time constant, τ, for the creep deformation. Adding glutaraldehyde, an agent that increases the covalent bonding of the cell surface, produced a significant increase in
k
1
together with a significant decrease in τ. This work represents a new attempt toward the understanding of the nanomechanical properties of single bacteria while they are under fluid conditions, which could be of practical value for elucidating, for instance, the biomechanical effects of drugs (such as antibiotics) on pathogens.
Protective Action of ppGpp in Microcin J25-Sensitive Strains
Authors: Pomares María Fernanda , Vincent Paula A. , Farías Ricardo N. , Salomón Raúl A.
Published: April 2008

AsEscherichia colistrains enter the stationary phase of growth they become more resistant to the peptide antibiotic microcin J25. It is known that starvation for nutrients such as amino acids or glucose leads to increases in guanosine 3′,5′-bispyrophosphate (ppGpp) levels and that the intracellular concentration of this nucleotide increases as cells enter the stationary phase of growth. Therefore, we examined the effects of artificially manipulating the ppGpp levels on sensitivity to microcin J25. A direct correlation was found between ppGpp accumulation and microcin resistance. Our results indicate that the nucleotide is required to induce production of YojI, a chromosomally encoded efflux pump which, in turn, expels microcin from cells. This would maintain the intracellular level of the antibiotic below a toxic level.
Single Gene Deletions of
mrpA
to
mrpG
and
mrpE
Point Mutations Affect Activity of the Mrp Na
+
/H
+
Antiporter of Alkaliphilic
Bacillus
and Formation of Hetero-Oligomeric Mrp Complexes
Authors: Morino Masato , Natsui Shinsuke , Swartz Talia H. , Krulwich Terry A. , Ito Masahiro
Published: April 2008

Mrp antiporters catalyze secondary Na
+
(Li
+
)/H
+
antiport and/or K
+
/H
+
antiport that is physiologically important in diverse bacteria. An additional capacity for anion flux has been observed for a few systems. Mrp is unique among antiporters in that it requires all six or seven hydrophobic gene products (MrpA to MrpG) of the
mrp
operon for full antiporter activity, but MrpE has been reported to be dispensable. Here, the membrane complexes formed by Mrp proteins were examined using a cloned
mrp
operon from alkaliphilic
Bacillus
pseudofirmus OF4. The operon was engineered so that the seven Mrp proteins could be detected in single samples. Membrane extracts of an antiporter-deficient
Escherichia coli
strain expressing this construct were analyzed by blue native-sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Mrp complexes of two sizes were identified containing all seven Mrp proteins. Studies of the single nonpolar
mrp
gene deletions in the construct showed that a subcomplex of MrpA, MrpB, MrpC, and MrpD was formed in the absence of MrpE, MrpF, or MrpG. By contrast, MrpE, MrpF, and MrpG were not observed in membranes lacking MrpA, MrpB, MrpC, or MrpD. Although MrpA and MrpD have been hypothesized to be the antiporter proteins, the MrpA-to-D complex was inactive. Every Mrp protein was required for an activity level near that of the wild-type Na
+
/H
+
antiporter, but a very low activity level was observed in the absence of MrpE. The introduction of an MrpE(P114G) mutation into the full Mrp complex led to antiport activity with a greatly increased apparent

K
m

value for Na
+
. The results suggested that interactions among the proteins of heterooligomeric Mrp complexes strongly impact antiporter properties.
Role of glucose metabolism in the recovery of postischemic LV mechanical function: effects of insulin and other metabolic modulators
Authors: Gandhi Manoj , Finegan Barry A. , Clanachan Alexander S.
Published: April 2008

The role of proton (H+) production from glucose metabolism in the recovery of myocardial function during postischemic reperfusion and its alteration by insulin and other metabolic modulators were examined. Rat hearts were perfused in vitro with Krebs-Henseleit solution containing palmitate (1.2 mmol/l) and glucose (11 mmol/l) under nonischemic conditions or during reperfusion following no-flow ischemia. Perfusate contained normal insulin (n-Ins, 50 mU/l), zero insulin (0-Ins), or supplemental insulin (s-Ins, 1,000 mU/l) or other metabolic modulators [dichloroacetate (DCA) at 3 mmol/l, oxfenicine at 1 mmol/l, and N6-cyclohexyladenosine (CHA) at 0.5 μmol/l]. Relative to n-Ins, 0-Ins depressed rates of glycolysis and glucose oxidation in nonischemic hearts and impaired recovery of postischemic function. Relative to n-Ins, s-Ins did not affect aerobic glucose metabolism and did not improve recovery when present during reperfusion. When present during ischemia and reperfusion, s-Ins impaired recovery. Combinations of metabolic modulators with s-Ins stimulated glucose oxidation ∼2.5-fold in nonischemic hearts and reduced H+ production. DCA and CHA, in combination with s-Ins, improved recovery of function, but addition of oxfenicine to this combination provided no further benefit. Although DCA and CHA were each partially protective in hearts perfused with n-Ins, optimal protection was achieved with DCA + CHA; recovery of function was inversely proportional to H+ production during reperfusion. Although supplemental insulin is not beneficial, elimination of H+ production from glucose metabolism by simultaneous inhibition of glycolysis and stimulation of glucose oxidation optimizes recovery of postischemic mechanical function.
CD4+ T lymphocytes mediate hypercholesterolemia-induced endothelial dysfunction via a NAD(P)H oxidase-dependent mechanism
Authors: Wolfort Ryan M. , Stokes Karen Y. , Granger D. Neil
Published: April 2008

Although hypercholesterolemia is known to impair endothelium-dependent vasodilation (EDV) long before the appearance of atherosclerotic plaques, it remains unclear whether the immune mechanisms that have been implicated in atherogenesis also contribute to the early oxidative stress and endothelial cell dysfunction elicited by hypercholesterolemia. EDV (wire myography), superoxide generation (cytochrome c reduction), and NAD(P)H oxidase mRNA expression were monitored in aortic rings from wild-type (WT) and mutant mice placed on either a normal diet or a cholesterol-enriched diet (HC) for 2 wk. WT mice on HC exhibited impaired EDV, enhanced superoxide generation, and increased expression of NAD(P)H oxidase subunit Nox-2 mRNA. The impaired EDV and increased superoxide generation induced by HC were significantly blunted in severe combined immunodeficient (SCID) mice and CD4+ T lymphocyte-deficient mice. These responses were also attenuated in HC mice genetically deficient in IFN-γ; however, adoptive transfer of WT-HC CD4+ T lymphocytes to IFN-γ-deficient recipients restored HC-induced responses. The HC-induced impaired EDV and oxidative stress were also attenuated in HC mice genetically deficient in Nox-2 (gp91phox−/−) and in WT→gp91phox−/−-HC chimeras. HC-induced gp91phoxmRNA expression was significantly blunted in mice deficient in CD4+ T cells or IFN-γ and was restored with adoptive transfer of WT-HC CD4+ T cells to IFN-γ-deficient recipients. These findings implicate the immune system in the early endothelial cell dysfunction associated with hypercholesterolemia and are consistent with a mechanism of impaired EDV that is mediated by CD4+ T cells and IFN-γ, acting through the generation of superoxide from vascular NAD(P)H oxidase.
High-fat diet-induced obesity leads to increased NO sensitivity of rat coronary arterioles: role of soluble guanylate cyclase activation
Authors: Jebelovszki Eva , Kiraly Csaba , Erdei Nora , Feher Attila , Pasztor Eniko T. , Rutkai Ibolya , Forster Tamas , Edes Istvan , Koller Akos , Bagi Zsolt
Published: April 2008

The impact of obesity on nitric oxide (NO)-mediated coronary microvascular responses is poorly understood. Thus NO-mediated vasomotor responses were investigated in pressurized coronary arterioles (∼100 μm) isolated from lean (on normal diet) and obese (fed with 60% of saturated fat) rats. We found that dilations to acetylcholine (ACh) were not significantly different in obese and lean rats (lean, 83 ± 4%; and obese, 85 ± 3% at 1 μM), yet the inhibition of NO synthesis with Nω-nitro-l-arginine methyl ester reduced ACh-induced dilations only in vessels of lean controls. The presence of the soluble guanylate cyclase (sGC) inhibitor oxadiazolo-quinoxaline (ODQ) elicited a similar reduction in ACh-induced dilations in the two groups of vessels (lean, 60 ± 11%; and obese, 57 ± 3%). Dilations to NO donors, sodium nitroprusside (SNP), and diethylenetriamine (DETA)-NONOate were enhanced in coronary arterioles of obese compared with lean control rats (lean, 63 ± 6% and 51 ± 5%; and obese, 78 ± 5% and 70 ± 5%, respectively, at 1 μM), whereas dilations to 8-bromo-cGMP were not different in the two groups. In the presence of ODQ, both SNP and DETA-NONOate-induced dilations were reduced to a similar level in lean and obese rats. Moreover, SNP-stimulated cGMP immunoreactivity in coronary arterioles and also cGMP levels in carotid arteries were enhanced in obese rats, whereas the protein expression of endothelial NOS and the sGC β1-subunit were not different in the two groups. Collectively, these findings suggest that in coronary arterioles of obese rats, the increased activity of sGC leads to an enhanced sensitivity to NO, which may contribute to the maintenance of NO-mediated dilations and coronary perfusion in obesity.
Differential loss of cytochrome-coxidase subunits in ischemia-reperfusion injury: exacerbation of COI subunit loss by PKC-ε inhibition
Authors: Yu Qilin , Nguyen Tiffany , Ogbi Mourad , Caldwell Robert W. , Johnson John A.
Published: April 2008

We have previously described a PKC-ε interaction with cytochrome oxidase subunit IV (COIV) that correlates with enhanced CO activity and cardiac ischemic preconditioning (PC). We therefore investigated the effects of PC and ischemia-reperfusion (I/R) injury on CO subunit levels in an anesthetized rat coronary ligation model. Homogenates prepared from the left ventricular regions at risk (RAR) and not at risk (RNAR) for I/R injury were fractionated into cell-soluble (S), 600 g low-speed centrifugation (L), gradient-purified mitochondrial (M), and 100,000 g particulate (P) fractions. In RAR tissue, PC (2 cycles of 5-min ischemia and 5-min reperfusion) decreased the COI in the P fraction (∼29% of total cellular COI), suggesting changes in interfibrillar mitochondria. After 30 min of ischemia and 120 min of reperfusion, total COI levels decreased in the RAR by 72%. Subunit Va was also downregulated by 42% following prolonged I/R in the RAR. PC administered before I/R reduced the loss of COI in the M and P fractions ∼30% and prevented COVa losses completely. We observed no losses in subunits Vb and VIIa following I/R alone; however, significant losses occurred when PC was administered before prolonged I/R. Delivery of a cell-permeable PKC-ε translocation inhibitor (εV1-2) to isolated rat hearts before prolonged I/R dramatically increased COI loss, suggesting that PKC-ε protects COI levels. We propose that additional measures to protect CO subunits when coadministered with PC may improve its cardioprotection against I/R injury.
Localization of the novel angiotensin peptide, angiotensin-(1-12), in heart and kidney of hypertensive and normotensive rats
Authors: Jessup Jewell A. , Trask Aaron J. , Chappell Mark C. , Nagata Sayaka , Kato Johji , Kitamura Kazuo , Ferrario Carlos M.
Published: April 2008

A low expression of angiotensinogen in the heart has been construed as indicating a circulating uptake mechanism to explain the local effects of angiotensin II on tissues. The recent identification of angiotensin-(1-12) in an array of rat organs suggests this propeptide may be an alternate substrate for local angiotensin production. To test this hypothesis, tissues from 11-wk-old spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats ( n = 14) were stained with purified antibodies directed to the COOH terminus of angiotensin-(1-12). Robust angiotensin-(1-12) staining was predominantly found in ventricular myocytes with less staining found in the medial layer of intracoronary arteries and vascular endothelium. In addition, angiotensin-(1-12) immunoreactivity was present in the proximal, distal, and collecting renal tubules within the deep cortical and outer medullary zones in both strains. Preadsorption of the antibody with angiotensin-(1-12) abolished staining in both tissues. Corresponding tissue measurements by radioimmunoassay showed 47% higher levels of angiotensin-(1-12) in the heart of SHR compared with WKY rats ( P < 0.05). In contrast, renal angiotensin-(1-12) levels were 16.5% lower in SHR compared with the WKY rats ( P < 0.05). This study shows for first time the localization of angiotensin-(1-12) in both cardiac myocytes and renal tubular components of WKY and SHR. In addition, we show that increased cardiac angiotensin-(1-12) concentrations in SHR is associated with a small, but statistically significant, reduction in renal angiotensin-(1-12) levels.
Mao and China's Relations with the Superpowers in the 1950s
Authors: Sheng Michael M.
Published: April 2008

This article reexamines the Taiwan Strait Crises of 1954—55 and 1958, and the initial Sino—Soviet conflict, with particular attention to Mao's dominant role in the events. In contrast to previous scholarship, based on newly available sources it finds Mao to have been an erratic dictator who micromanaged China's military and political operations in the Taiwan Strait against the U.S.—Taiwan alliance with neither a long-term strategy nor a short-term plan. Mao's grandiose ambition to be the leader of the communist world led him into a conflict with Moscow, and the Sino—Soviet alliance began to unravel when China most needed allies. In the end, Mao's policy behavior was counterproductive and self-defeating; China's national interest, which Mao thought he was protecting and enhancing, suffered a great deal of damage.
Beyond Sexual Abuse: The Impact of Other Maltreatment Experiences On Sexualized Behaviors
Authors: Merrick Melissa T. , Litrownik Alan J. , Everson Mark D. , Cox Christine E.
Published: April 2008

This study sought to broaden research findings linking maltreatment to sexualized behaviors by investigating whether maltreatment experiences other than sexual abuse predict such behaviors. The sample included 690 children without reported sexual abuse histories who are participants in the LONGSCAN Consortium, a prospective multisite investigation of childhood maltreatment. Child Protective Service reports before age 8 years and caregiver reports on the Child Sexual Behavior Inventory-II at age 8 years were used to examine the relationship between maltreatment timing and type, and sexualized behaviors. Logistic regression analyses suggested that early (< 4) and late (4-8) reports of physical abuse were associated with more sexualized behaviors (odds ratios = 1.9-2.6). The pattern differed by gender, with physical abuse predicting sexual intrusiveness and displaying private parts in boys, and boundary problems in girls. Findings suggest that maltreatment other than sexual abuse, and the developmental periods in which it occurs, may be linked to the development of sexualized behaviors.
Sexual Anxiety and Eroticism Predict the Development of Sexual Problems in Youth With a History of Sexual Abuse
Authors: Simon Valerie A. , Feiring Candice
Published: April 2008

Youth with confirmed histories of sexual abuse (N = 118) were followed longitudinally to examine associations between their initial sexual reactions to abuse and subsequent sexual functioning. Participants were interviewed at abuse discovery (ages 8 through 15) and again 1 and 6 years later. Eroticism and sexual anxiety emerged as distinct indices of abuse-specific sexual reactions and predicted subsequent sexual functioning. Eroticism was associated with indicators of heightened sexuality, including more sexual risk behavior and views of sexual intimacy focused on partners' needs. Sexual anxiety was associated with indicators of diminished sexuality, including few sexual partners and avoidant views of sexual intimacy. Age at abuse discovery moderated some associations, suggesting that the timing of abuse-specific reactions affects trajectories of sexual development. Findings point to the need for a developmental approach to understanding how abuse-specific sexual reactions disrupt sexual development and the need for early interventions promoting healthy sexual development.
The role of iron dysregulation in the pathogenesis of multiple sclerosis: an Egyptian study
Authors: Abo-Krysha N , Rashed L
Published: April 2008

Background

Iron is essential for virtually all types of cells and organisms. The significance of iron for brain function is reflected by the presence of receptors for transferrin on brain capillary endothelial cells. Iron imbalance is associated with proinflammatory cytokines and oxidative stress, which have been implicated in the pathogenesis of multiple sclerosis (MS). Transferrin receptor (TfR) is the major mediator of iron uptake. Its expression is increased to facilitate iron entrance into the cell. The increased serum level of soluble transferrin receptor (sTfR) may indicate an abnormal intracellular distribution of iron and a decrease in the cytoplasmic compartment.

Objective

Our objective is to assess the possible role of iron metabolism dysfunction in the pathogenesis of MS.

Methods

Thirty subjects were selected from the Neurology Department of Kasr El-Aini hospital, Cairo University: 20 MS patients, where nine patients were relapsing and progressive (secondary progressive (SP) of which six were secondary progressive active (SP-A) and three were secondary progressive stable (SP-S)), seven were relapsing–remitting active (RR-A) and four were primary progressive (PP); and 10 control subjects matched in age and sex. Each patient was subjected to a thorough general medical and neurological examination, Kurtzke MS rating scales, laboratory assessment, neuro-imaging, evoked potentials and quantitative determination of the indices of iron metabolism, such as serum iron and sTfR.

Results

The serum level of sTfR was significantly higher in our MS patients compared with the control group ( p = 0.0001). The levels were significantly higher in SP-A ( p = 0.001), SP-S ( p = 0.01), RR-A ( p = 0.0001) and PP ( p = 0.003) patients than in controls. Iron values were within normal limits in all patients. The increased serum sTfR level in non-anemic MS patients with active disease reflects the increased iron turnover. The elevation of sTfR levels in stable patients may indicate active inflammation with ongoing oxidative damage that is not detectable by history or examination.

Conclusions

Iron overload and upregulation of iron-handling proteins, such as TfR, in the MS brain can contribute to pathogenesis of Multiple Sclerosis and iron imbalance is associated with a prooxidative stress and a proinflammatory environment, this suggest that iron could be a target for MS therapy to improve neuronal iron metabolism.
The PI3K pathway regulates endochondral bone growth through control of hypertrophic chondrocyte differentiation
Authors: Ulici Veronica , Hoenselaar Katie D , Gillespie J Ryan , Beier Frank
Published: April 2008

Background

The majority of our bones develop through the process of endochondral ossification that involves chondrocyte proliferation and hypertrophic differentiation in the cartilage growth plate. A large number of growth factors and hormones have been implicated in the regulation of growth plate biology, however, less is known about the intracellular signaling pathways involved. PI3K/Akt has been identified as a major regulator of cellular proliferation, differentiation and death in multiple cell types.

Results and Discussion

Employing an organ culture system of embryonic mouse tibiae and LY294002, a pharmacological inhibitor of PI3K, we show that inhibition of the pathway results in significant growth reduction, demonstrating that PI3K is required for normal endochondral bone growth in vitro. PI3K inhibition reduces the length of the proliferating and particularly of the hypertrophic zone. Studies with organ cultures and primary chondrocytes in micromass culture show delayed hypertrophic differentiation of chondrocytes and increased apoptosis in the presence of LY294002. Surprisingly, PI3K inhibition had no strong effect on IGF1-induced bone growth, but partially blocked the anabolic effects of C-type natriuretic peptide.

Conclusion

Our data demonstrate an essential role of PI3K signaling in chondrocyte differentiation and as a consequence of this, in the endochondral bone growth process.
The evolutionary trajectory of the mating-type (mat) genes in Neurosporarelates to reproductive behavior of taxa
Authors: Wik Lotta , Karlsson Magnus , Johannesson Hanna
Published: April 2008

Background

Comparative sequencing studies among a wide range of taxonomic groups, including fungi, have led to the discovery that reproductive genes evolve more rapidly than other genes. However, for fungal reproductive genes the question has remained whether the rapid evolution is a result of stochastic or deterministic processes. The mating-type (mat) genes constitute the master regulators of sexual reproduction in filamentous ascomycetes and here we present a study of the molecular evolution of the four mat-genes (mat a-1, mat A-1, mat A-2 and mat A-3) of 20 Neurospora taxa.

Results

We estimated nonsynonymous and synonymous substitution rates of genes to infer their evolutionary rate, and confirmed that the mat-genes evolve rapidly. Furthermore, the evolutionary trajectories are related to the reproductive modes of the taxa; likelihood methods revealed that positive selection acting on specific codons drives the diversity in heterothallic taxa, while among homothallic taxa the rapid evolution is due to a lack of selective constraint. The latter finding is supported by presence of stop codons and frame shift mutations disrupting the open reading frames of mat a-1, mat A-2 and mat A-3 in homothallic taxa. Lower selective constraints of mat-genes was found among homothallic than heterothallic taxa, and comparisons with non-reproductive genes argue that this disparity is not a nonspecific, genome-wide phenomenon.

Conclusion

Our data show that the mat-genes evolve rapidly in Neurospora. The rapid divergence is due to either adaptive evolution or lack of selective constraints, depending on the reproductive mode of the taxa. This is the first instance of positive selection acting on reproductive genes in the fungal kingdom, and illustrates how the evolutionary trajectory of reproductive genes can change after a switch in reproductive behaviour of an organism.
Failure of oral E. coli O83 lipopolysaccharide to influence intestinal morphology and cell proliferation in rats: Short communication
Authors: Illyés György , Kovács Krisztina , Kocsis Béla , Baintner Károly
Published: April 2008

It is known that bacterial lipopolysaccharide (LPS) is not absorbed from the gastrointestinal tract in significant quantities. However, the question remained whether oral LPS modified the structure or function of the gut. In the present experiment
Escherichia coli
O83 LPS was administered to growing rats in repeated oral doses of 400 mg/kg body weight (b. w.), every 8 h. After three days of treatment, morphometric and histochemical examinations of the small intestine did not show significant differences between treated and control rats. It is concluded that repeated oral administration of high doses of
E. coli
O83 LPS had no demonstrable effect on intestinal structure and cell proliferation in a rat model.
Proliferative and necrotising pneumonia and severe vascular lesions in pigs naturally infected with porcine circovirus type 2
Authors: Szeredi Levente , Szentirmai Csaba
Published: April 2008

Severe disease induced by porcine circovirus type 2 (PCV2) was observed in three pigs originating from a large herd affected by respiratory and digestive signs as well as wasting. Proliferative and necrotising pneumonia (PNP) was diagnosed in two animals, while severe acute interstitial pneumonia characterised by the presence of abundant hyaline membrane in the alveoli and fibrin in the bronchioles was found in one pig. In all cases, large amounts of PCV2 antigen were found in each tissue sample collected from the lungs and mediastinal lymph nodes. Neither porcine reproductive and respiratory syndrome virus (PRRSV) nor swine influenza virus (SIV) was detected, and no bacteria could be cultured in any of the cases. Vascular lesions, e.g. degeneration of endothelial cells, perivascular and intramural oedema, fibrinoid necrosis, vasculitis, perivasculitis, and vascular thrombi were observed in all cases, associated with the presence of PCV2 antigen. The viral antigen was present in the intravascular mononuclear cells, endothelial cells, myocytes and infiltrating inflammatory cells in lymph and blood vessels. In one case, obliterating thrombi in the lymph and blood vessels were directly connected to areas of tissue necrosis and were associated with abundant PCV2 antigen. The results further suggest the causative role of PCV2 infection in PNP, and the importance of the vascular system in the pathogenesis of PCV2-associated diseases of swine.
Acrosomal and viability status of bovine spermatozoa evaluated by two staining methods
Authors: Jankovičová Jana , Simon Michal , Antalíková Jana , Horovská Ľubica
Published: April 2008

Artificial insemination with frozen-thawed spermatozoa is commonly used in cattle breeding. A simple and fast procedure is needed for routine evaluation of the acrosomal status of frozen-thawed bovine sperm. Therefore, the purpose of this study was to test two staining procedures used to determine the viability and integrity of acrosome of frozen-thawed bovine spermatozoa. Double staining and Hoechst/FITC-Pisum sativumagglutinin (FITC-PSA) labelling were tested for evaluating the viability and acrosome reaction induced by calcium ionophore of bull spermatozoa. In our experiments no significant differences were detected in the frequency of acrosome-reacted sperm either by double staining (37.98%) or by FITC-PSA labelling (39.33%). The viability of sperm stained by the double staining method was 67.17%, and a higher portion of viable sperm (82.67%) was observed by staining with the Hoechst procedure (P < 0.01). On the basis of the results obtained it is concluded that both methods can be used for detecting the acrosome reaction of frozen-thawed bovine spermatozoa.
Salmonella Genomic Island 1 (SGI1) and genetic characteristics of animal and food isolates of Salmonella Typhimurium DT104 in Hungary
Authors: Fekete Péter , Nagy Béla
Published: April 2008

To study the genetic characteristics of DT104 strains of
Salmonella
Typhimurium and the prevalence of
Salmonella
Genomic Island (SGI1) in Hungary, 140 recent
Salmonella
strains of food and animal origin were examined. For the first time in Hungary, the SGI1 was found in 17 out of 59
S
. Typhimurium isolates (all proven to be DT104 phage type). These 17 strains were then subtyped by pulsed-field gel electrophoresis (PFGE) into 6 pulsotypes which were less correlated with the geographic origin than with the animal species of origin.
Further evidence for the involvement of anatomical parameters of the cardiopulmonary system in the development of ascites syndrome in broiler chickens
Authors: Hassanzadeh Mohammad , Buyse Johan , Decuypere Eddy
Published: April 2008

Eggs from a broiler line were incubated at two different altitudes and hatched. Relative heart and lung weights, volumes of the heart, lung and thoracic cavity, incidence of right ventricular hypertrophy and ascites, and related physiological parameters were followed in the day-old chickens hatched from the above eggs. Lung and heart weights as a percentage of body weight, lung and heart volumes relative to the volume of the thoracic cavity after removing the heart and lungs were higher in chickens hatched at high altitude. Additionally, embryonic triiodothyronine (T3) and thyroxine (T4) levels relative to cardiopulmonary parameters were higher in day-old chickens that hatched at high altitude as compared with chickens hatched at low altitude. This was associated with a lower incidence of right ventricular hypertrophy and ascites in chickens hatched at high altitude. Our data indicate that chronic hypoxia interacting with the endogenous functions of embryos during embryonic development at high altitude, as adaptation mechanisms, changed the developmental trajectories of cardiopulmonary parameters in postnatal chickens. This important development facilitates an increase in the gas exchange area in broiler chickens, thus lowering their susceptibility to pulmonary hypertension and ascites.
Seroprevalence of Toxoplasma gondii and Neospora caninum infection of cats in Hungary
Authors: Hornok Sándor , Edelhofer Renate , Joachim Anja , Farkas Róbert , Berta Krisztián , Répási Attila , Lakatos Béla
Published: April 2008

Blood samples were collected from 330 cats in Hungary in order to evaluate their seroconversion toToxoplasma gondiiandNeospora caninumusing the indirect fluorescent antibody test (IFAT). The overall prevalence of toxoplasmosis was 47.6%, the prevalence being 22.4% among urban, 50% among suburban and 61.3% among rural animals. Significantly more cats had high IFAT titres (1:640 to 1:5120) in the countryside. Female cats were more frequently infected withT. gondiithan males (53.3% vs. 39.3%), and seropositivity increased with the age of animals. The prevalence (0.6%) and titre (1:40) of antibodies toN. caninumwas low. Sixty-two cats were also screened for seroconversion to feline infectious peritonitis (FIP) virus. Higher titres toT. gondiiwere more frequently detected among FIP-positive cats, but this difference was non-significant due to the small number of cats with concurrent infection.
Appendix mucokele laparoscopes műtéti megoldásar
Authors: Temesi Rita , Bezsilla János , Botos Ákos , Sikorszki László , Berecz János , Pap Tímea , Ludvig Zsuzsanna , Bende Sándor
Published: April 2008

Absztrakt

A mucokele mucinnal telt, tágult, egy- vagy többrekeszű üreg, amely ritka az appendixben. A betegség legtöbbször tünetmentes, gyakran mellékleletként kerül felismerésre. Malignus elváltozások kizárása céljából részletes kivizsgálást igényel. A sebészi kezelés a műtéti lelettől, illetve a szövettani feldolgozástól függően appendectomiától a jobb oldali hemicolectomiáig terjedhet. Cikkünkben áttekintjük a betegség klinikumát, diagnosztikus lehetőségeit, valamint saját tapasztalataink figyelembevételével a műtéti megoldásokat. Öt beteget mutatunk be, kiknél három esetben jobb alhasban tapintható fájdalmatlan rezisztencia, egy esetben bizonytalan jobb alhasi fájdalmak, egy esetben hasi fájdalmak, fokozódó hasmenés miatt indult kivizsgálás, melynek során hasi ultrahang és CT-vizsgálatok felvetették a mucokele lehetőségét, colonoscopos vizsgálat intraluminalis eltérést nem talált. Laparoscopos exploratiót követően két esetben laparoscoppal asszisztált coecumkúp-resectiót, két esetben laparoscopos appendectomiát és egy esetben laparoscopos coecumkúp-resectiót végeztünk. A szövettani feldolgozás appendix mucokelét igazolt malignitásra utaló jel nélkül. Mindegyik betegünk szövődménymentesen gyógyult, a posztoperatív 5. napon emittáltuk őket. A mai napig, 6–30 hónapos követés után, betegeink panaszmentesek. Az appendix mucokele műtéti megoldásaként ajánlható a laparoscopos technika.