bluuebunny/crossref_metadata_2025_split huggingface dataset:
Roles of immunoglobulin‐like loops of junctional cell adhesion molecule 4; involvement in the subcellular localization and the cell adhesion
Authors: Tajima Makiko , Hirabayashi Susumu , Yao Ikuko , Shirasawa Madoka , Osuga Junichi , Ishibashi Shun , Fujita Toshiro , Hata Yutaka 
Published: August 2003

AbstractBackground:  Membrane‐associated guanylate kinase with inverted domain structure‐1 (MAGI‐1) is a scaffolding protein at tight junctions (TJs). We have recently identified junctional adhesion molecule 4 (JAM4) as a MAGI‐1‐interacting protein. JAM4 belongs to the immunoglobulin superfamily and mediates Ca2+‐independent adhesion. In this study, we examined the subcellular localization of JAM4 in various tissues and the involvement of JAM4 in the localization of MAGI‐1. Moreover, we investigated into roles of immunoglobulin‐like loops (Ig‐loops) of JAM4.Results:  JAM4 was localized at TJs but also on apical membranes of epithelial cells in jejunum, ileum, and renal proximal tubules. In Madine Darby canine kidney (MDCK) cells, the localization of JAM4 at TJs depended on the first Ig‐loop and did not require the MAGI‐1‐interacting region. JAM4 determined the subcellular localization of MAGI‐1 in MDCK cells. In ileum, however, MAGI‐1 was localized at TJs where JAM4 was not detected. Both of Ig‐loops were necessary for homophilic interactions, but cis interactions depended on the first Ig‐loop.Conclusion:  JAM4 may be primarily targeted to apical membranes, and subsequently recruited to TJs through the first Ig‐loop–mediated molecular interaction. JAM4 determines the localization of MAGI‐1 in MDCK cells, but the in vivo localization of MAGI‐1 does not necessarily depend on JAM4.
Insomnia related to postmenopausal syndrome and hormone replacement therapy: sleep laboratory studies on baseline differences between patients and controls and double‐blind, placebo‐controlled investigations on the effects of a novel estrogen–progestogen combination (Climodien®, Lafamme®) versus estrogen alone
Authors: Saletu‐Zyhlarz Gerda , Anderer Peter , Gruber Georg , Mandl Magdalena , Gruber Doris , Metka Markus , Huber Johannes , Oettel Michael , Gräser Thomas , Abu‐Bakr Manal Hassan , Grätzhofer Elisabeth , Saletu Bernd 
Published: August 2003

SummaryDifferences in sleep and awakening quality between 51 insomniac postmenopausal syndrome patients and normal controls were evaluated. In a subsequent double‐blind, placebo‐controlled, comparative, randomized, three‐arm trial (Climodien 2/3 = estradiol valerate 2 mg + the progestogen dienogest 3 mg = regimen A, estradiol valerate 2 mg = regimen EV, and placebo = regimen P), the effects of 2 months of hormone replacement therapy were investigated, followed by a 2‐month open‐label phase in which all patients received Climodien® 2/2 (EV 2 mg + dienogest 2 mg = regimen A*). Polysomnography at baseline demonstrated significantly deteriorated sleep initiation and maintenance, increased S1 and decreased S2 in patients. Subjective sleep and awakening quality, well‐being, morning drive, wakefulness, memory and reaction time performance were deteriorated too. Treatment with both regimen A and regimen EV induced a moderate, although nonsignificant, improvement in the primary efficacy variable wakefulness during the total sleep period compared with baseline, while under placebo no changes occurred. Secondary efficacy variables concerning sleep initiation and maintenance, and sleep architecture showed similar findings. The apnea and apnea–hypopnea indices improved significantly under regimen A, compared with both baseline and placebo. Subjective sleep and awakening quality improved significantly after regimen A and EV compared with baseline, with the drug‐induced changes being superior to those induced by placebo. In the open‐label phase, subjective sleep quality improved further, significantly in the former regimen A group. Awakening quality, somatic complaints and morning thymopsyche did not yield any significant findings. Concerning morning noopsychic performance, memory improved significantly after regimen A compared with baseline, fine motor activity after regimen EV. Reaction time performance increased with all three compounds. In conclusion, Climodien significantly improved subjective sleep quality, the apnea and apnea–hypopnea indices of insomniac postmenopausal syndrome patients, while it only marginally improved variables concerning objective sleep and awakening quality.
Neurobehavioural performance effects of daytime melatonin and temazepam administration
Authors: Rogers Naomi L. , Kennaway David J. , Dawson Drew 
Published: August 2003

SummaryExogenous melatonin is a potential treatment for circadian disruption and insomnia. Hence, it is important to determine and quantify neurobehavioural performance effects associated with its use. The present study compared neurobehavioural performance following administration of melatonin and the benzodiazepine temazepam, using a within‐subjects design. Following a training day, 16 healthy, young subjects (six males, 10 females; mean age ± SEM, 21.4 ± 6 years) participated in a 3‐day protocol. After sleeping overnight in the laboratory, subjects completed a battery of tests at hourly intervals between 08:00 and 11:00 hours and at two hourly intervals between 13:00 and 17:00 hours. The neurobehavioural performance tasks included: unpredictable tracking, spatial memory, vigilance and logical reasoning. Subjective sleepiness was measured at hourly intervals using a visual analogue scale. At 12:00 h subjects were administered a capsule containing 5 mg melatonin, 10 mg temazepam or placebo, in a randomized, double‐blind crossover fashion. A significant drug × time interaction was evident on the unpredictable tracking, spatial memory and vigilance tasks (P < 0.05). Greater changes in performance were evident following temazepam administration than melatonin administration, relative to placebo. Administration of melatonin or temazepam significantly elevated subjective sleepiness levels, relative to placebo (P ≤ 0.05). The present findings demonstrate that melatonin administration induces a smaller deficit in performance on a range of neurobehavioural tasks than temazepam. Given melatonin's soporific and chronobiotic properties, these results suggest that melatonin may be preferable to benzodiazepines in the management of circadian and sleep disorders.
Phlebotomus (Adlerius) halepensis vector competence for Leishmania major and Le. tropica
Authors: Sádlová J. , Hajmová M. , Volf P. 
Published: August 2003

Abstract.  In Eurasia, phlebotomine sandflies of the subgenus Adlerius (Diptera: Psychodidae) comprise about 20 known species. Some are suspected vectors of visceral leishmaniasis (VL) and at least one species has been implicated as a vector of cutaneous leishmaniasis (CL). We tested Phlebotomus (Adlerius) halepensis Theodor (Jordan strain) for CL vector competence, compared with three standard vectors: Phlebotomus (Phlebotomus) duboscqi N‐L. from Senegal, Phlebotomus (Paraphlebotomus) sergenti Parrot from Turkey and the Neotropical Lutzomyia longipalpis (L. & N) (Jacobina strain). Sandfly females were membrane‐fed on amastigote suspensions of Leishmania major Y. & S. and Le. tropica (Wright) (Kinetoplastida: Trypanosomatidae) and examined for parasite development 3, 6 and 10 days post‐infection. Phlebotomus halepensis showed high susceptibility to both leishmanias, supporting typical suprapylarian parasite development similar to the other vectors. Phlebotomus halepensis infection rates were ∼90% for Le. major and ∼80% for Le. tropica, with high parasite densities. Development of infections was relatively fast, colonizing the thoracic midgut by 6 days post‐bloodmeal in every case and reaching the stomodeal valve in >80% of flies. In late‐stage infections, 10 days post‐bloodmeal, nearly all P. halepensis females had cardia and stomodeal valve filled with very high numbers of parasites and some Le. tropica‐infected females had promastigotes in the pharynx and proboscis.Host choice experiments in the laboratory showed that P. halepensis females fed readily on rat or rabbit and preferred the human forearm. In view of its vector competence and partial anthropophily, we infer that P. halepensis is a potential vector of cutaneous as well as visceral leishmaniases.
Mos10 (Vps60) is required for normal filament maturation in Saccharomyces cerevisiae
Authors: Köhler Julia R. 
Published: August 2003

SummaryEarly pseudohyphal growth of Saccharomyces cerevisiae is well described, and is known to be subject to a complex web of developmental regulation. In maturing filaments, young cells differ significantly from their pseudohyphal progenitors, in their shape, and in their timing and direction of cell division. The changes that occur during filament maturation result in round and oval cells surrounding and covering the pseudohyphal filament. In a screen for mutants that affect this process, a vacuolar protein sorting gene, MOS10 (VPS60), and a gene encoding an α subunit of the proteasome core, PRE9, were isolated. Characterization of the mos10/mos10 phenotype showed that the process of filament maturation is regulated differently from early filamentous growth, and that the requirement for Mos10 is limited to the maturation stage of pseudohyphal development. The mos10/mos10 phenotype is unlikely to be an unspecific effect of disruption of endocytosis or vacuolar protein sorting, because it is not recapitulated by mutants in other genes required for these processes. Disruption of homologues of MOS10, which act as components of the ESCRT‐III complex in targeting proteins for vacuolar degradation, results in abnormal early pseudohyphal growth, not in the filament maturation defect seen in mos10/mos10. Thus, Mos10 may function in targeting of specific cargo proteins for degradation, under conditions particular to maturing filaments.
Overexpression of a human and a fungal ABC transporter similarly suppresses the differentiation defects of a fungal peroxisomal mutant but introduces pleiotropic cellular effects
Authors: Boisnard Stéphanie , Zickler Denise , Picard Marguerite , Berteaux‐Lecellier Véronique 
Published: August 2003

SummaryAmong the peroxisome membrane proteins, some are required for peroxisome biogenesis (e.g. PEX2) while others are not, e.g. ABC (ATP‐binding cassette) transporters. Unexpectedly, overproduction of the peroxisomal ABC transporter PMP70 was found to be able to restore peroxisome biogenesis in mammalian pex2 mutant cell lines. In the filamentous fungus Podospora anserina, pex2 mutations not only impair peroxisome biogenesis but also cause a precise cell differentiation defect. Here, we show that both defects are partially suppressed by expression of the human cDNA encoding PMP70. In addition, PMP70 expression causes new developmental defects, different from those induced by pex2 mutations. We also show that overexpression of the P. anserina pABC1 gene, which encodes a peroxisomal ABC transporter, leads to similar effects. Taken together, our results demonstrate that: (i) the genetic relationship between PEX2 and PMP70, initially observed in mammals, has been conserved through evolution; (ii) the cell differentiation defect observed in the P. anserina pex2 mutants is indeed linked to impairment in peroxisome biogenesis; and (iii) unexpected detrimental cellular defects result from overproduction of peroxisomal ABC transporters.
The CtsR regulator of Listeria monocytogenes contains a variant glycine repeat region that affects piezotolerance, stress resistance, motility and virulence
Authors: Karatzas Kimon A. G. , Wouters Jeroen A. , Gahan Cormac G. M. , Hill Colin , Abee Tjakko , Bennik Marjon H. J. 
Published: August 2003

SummaryA spontaneous high hydrostatic pressure (HHP)‐tolerant mutant of Listeria monocytogenes ScottA, named AK01, was isolated previously. This mutant was immotile and showed increased resistance to heat, acid and H2O2 compared with the wild type (wt) (Karatzas, K.A.G. and Bennik, M.H.J. 2002 Appl Environ Microbiol 68: 3183–3189). In this study, we conclusively linked the increased HHP and stress tolerance of strain AK01 to a single codon deletion in ctsR (class three stress gene repressor) in a region encoding a highly conserved glycine repeat. CtsR negatively regulates the expression of the clp genes, including clpP, clpE and the clpC operon (encompassing ctsR itself), which belong to the class III heat shock genes. Allelic replacement of the ctsR gene in the wt background with the mutant ctsR gene, designated ctsRΔGly, rendered mutants with phenotypes and protein expression profiles identical to those of strain AK01. The expression levels of CtsR, ClpC and ClpP proteins were significantly higher in ctsRΔGly mutants than in the wt strain, indicative of the CtsRΔGly protein being inactive. Further evidence that the CtsRΔGly protein lacks its repressor function came from the finding that the Clp proteins in the mutant were not further induced upon heat shock, and that HHP tolerance of a ctsR deletion strain was as high as that of a ctsRΔGly mutant. The high HHP tolerance possibly results from the increased expression of the clp genes in the absence of (active) CtsR repressor. Importantly, the strains expressing CtsRΔGly show significantly attenuated virulence compared with the wt strain; however, no indication of disregulation of PrfA in the mutant strains was found. Our data highlight an important regulatory role of the glycine‐rich region of CtsR in stress resistance and virulence.
A subset of bacterial inner membrane proteins integrated by the twin‐arginine translocase
Authors: Hatzixanthis Kostas , Palmer Tracy , Sargent Frank 
Published: August 2003

SummaryA group of bacterial exported proteins are synthesized with N‐terminal signal peptides containing a SRRxFLK ‘twin‐arginine’ amino acid motif. Proteins bearing twin‐arginine signal peptides are targeted post‐translationally to the twin‐arginine translocation (Tat) system which transports folded substrates across the inner membrane. In Escherichia coli, most integral inner membrane proteins are assembled by a co‐translational process directed by SRP/FtsY, the SecYEG translocase, and YidC. In this work we define a novel class of integral membrane proteins assembled by a Tat‐dependent mechanism. We show that at least five E. coli Tat substrate proteins contain hydrophobic C‐terminal transmembrane helices (or ‘C‐tails’). Fusions between the identified transmembrane C‐tails and the exclusively Tat‐dependent reporter proteins TorA and SufI render the resultant chimeras membrane‐bound. Export‐linked signal peptide processing and membrane integration of the chimeras is shown to be both Tat‐dependent and YidC‐independent. It is proposed that the mechanism of membrane integration of proteins by the Tat system is fundamentally distinct from that employed for other bacterial inner membrane proteins.
CaSPA2is important for polarity establishment and maintenance inCandida albicans
Authors: Zheng Xin‐De , Wang Yan‐Ming , Wang Yue 
Published: August 2003

SummarySaccharomyces cerevisiaeSpa2p is a component of polarisome that controls cell polarity. Here, we have characterized the role of its homologue, CaSpa2p, in the polarized growth inCandida albicans. During yeast growth, GFP‐tagged CaSpa2p localized to distinct growth sites in a cell cycle‐dependent manner, while during hyphal growth it persistently localized to hyphal tips throughout the cell cycle. Persistent tip localization of the protein was also observed inCatup1Δ andCanrg1Δ, mutants constitutive for filamentous growth.Caspa2Δ exhibited defects in polarity establishment and maintenance, such as random budding and failure to confine growth to a small surface area leading to round cells with wide, elongated bud necks and markedly thicker hyphae. It was also defective in nuclear positioning, presumably a result of defective interactions between cytoplasmic microtubules with certain polarity determinants. The highly conserved SHD‐I and SHD‐V domains were found to be important and responsible for different aspects of CaSpa2p function.Caspa2Δ exhibited no virulence in the mouse systemic candidiasis model. Because of the existence of distinct growth forms and the easy control of the switch between themin vitro,C. albicansmay serve as a useful model in cell polarity research.
SpoIVB‐mediated cleavage of SpoIVFA could provide the intercellular signal to activate processing of Pro‐σK in Bacillus subtilis
Authors: Dong Tran C. , Cutting Simon M. 
Published: August 2003

SummarySpoIVB is the critical determinant for intercompartmental signalling of pro‐σK processing during sporulation in Bacillus subtilis. We show here that the SpoIVB serine peptidase can cleave the SpoIVFA protein, which is one component of the pro‐σK processing complex. SpoIVFA has been shown elsewhere (Rudner, D.Z., and Losick, R., 2002, Genes Dev 16: 1007–1018) to tether BofA and SpoIVFB in a membrane‐embedded heteroligomeric complex in which BofA directly inhibits the activity of SpoIVFB. Cleavage of SpoIVFA would provide the necessary signal to dissolve this complex and release BofA‐mediated inhibition on the zinc metalloprotease, SpoIVFB, that is responsible for cleaving pro‐σK to its mature form. We also show that the SpoIVB PDZ domain is required for self‐recognition and trans cleavage of SpoIVB and is probably also used to target an internal motif within the C‐terminal region of SpoIVFA exposed in the space between the inner and outer forespore membranes. This work reveals the mechanism of intercompartmental signalling and provides a unified model as to how σK‐directed gene expression in the mother cell is co‐ordinated with events in the forespore chamber.
Ku80 plays a role in non‐homologous recombination but is not required for T‐DNA integration inArabidopsis
Authors: Gallego M. E. , Bleuyard J.‐Y. , Daoudal‐Cotterell S. , Jallut N. , White C. I. 
Published: August 2003

SummaryChromosomal breaks are repaired by homologous recombination (HR) or non‐homologous end joining (NHEJ) mechanisms. The Ku70/Ku80 heterodimer binds DNA ends and plays roles in NHEJ and telomere maintenance in organisms ranging from yeast to humans. We have previously identified aku80mutant of the model plantArabidopsis thalianaand shown the role of Ku80 in telomere homeostasis in plant cells. We show here that this mutant is hypersensitive to the DNA‐damaging agent methyl methane sulphonate and has a reduced capacity to carry out NHEJ recombination. To understand the interplay between HR and NHEJ in plants, we measured HR in the absence of Ku80. We find that the frequency of intrachromosomal HR is not affected by the absence of Ku80. Previous work has clearly implicated the Ku heterodimer inAgrobacterium‐mediated T‐DNA transformation of yeast. Surprisingly,ku80mutant plants show no defect in the efficiency of T‐DNA transformation of plants withAgrobacterium, showing that an alternative pathway must exist in plants.
Mutation of the regulatory phosphorylation site of tobacco nitrate reductase results in constitutive activation of the enzyme in vivo and nitrite accumulation
Authors: Lillo Cathrine , Lea Unni S. , Leydecker Marie‐Thérèse , Meyer Christian 
Published: August 2003

SummaryIn wild‐type Nicotiana plumbaginifolia and other higher plants, nitrate reductase (NR) is rapidly inactivated/activated in response to dark/light transitions. Inactivation of NR is believed to be caused by phosphorylation at a special conserved regulatory Ser residue, Ser 521, and interactions with divalent cations and inhibitory 14‐3‐3 proteins. A transgenic N. plumbaginifolia line (S521) was constructed where the Ser 521 had been changed by site‐directed mutagenesis into Asp. This mutation resulted in complete abolishment of inactivation in response to light/dark transitions or other treatments known to inactivate NR. During prolonged darkness, NR in wild‐type plants is in the inactivated form, whereas NR in the S521 line is always in the active form. Differences in degradation rate between NR from S521 and lines with non‐mutated NR were not found. Kinetic constants like Km values for NADH and NO3− were not changed, but a slightly different pH profile was observed for mutated NR as opposed to non‐mutated NR. Under optimal growth conditions, the phenotype of the S521 plants was not different from the wild type (WT). However, when plants were irrigated with high nitrate concentration, 150 mm, the transgenic plants accumulated nitrite in darkness, and young leaves showed chlorosis.
A new single‐locus cytogenetic mapping system for maize (Zea mays L.): overcoming FISH detection limits with marker‐selected sorghum (S. propinquum L.) BAC clones
Authors: Koumbaris George L. , Bass Hank W. 
Published: August 2003

SummaryThe development of a cytogenetic map for maize (Zea mays L.) is shown to be feasible by means of a combination of resources from sorghum and oat that overcome limitations of single‐copy gene detection. A maize chromosome‐addition line of oat, OMAd9.2, provided clear images of optically isolated pachytene chromosomes through a chromosome spread and painting technique. A direct labeled oligonucleotide fluorescence in situ hybridization (FISH) probe MCCY specifically stained the centromere. The arm ratio (long/short) for maize chromosome 9 in the addition line was 1.7, comparable to the range of 1.6–2.1 previously reported for maize chromosome 9. A sorghum (Sorghum propinquum L.) BAC library was screened by hybridization with each of three maize core‐bin‐marker (CBM) probes: umc109 (CBM9.01), umc192/bz1 (CBM9.02), and csu54b (CBM9.08). A single BAC clone for each marker was chosen; designated sCBM9.1, sCBM9.2, or sCBM9.8; and used as a FISH probe on pachytene spreads from OMAd9.2. In each case, discrete FISH signals were observed, and their cytogenetic positions were determined to be 9S.79 (at position 79% of the length of chromosome 9 short arm) for sCBM9.1, 9S.65 for sCBM9.2, and approximately 9L.95 for sCBM9.8. These map positions were co‐linear with linkage‐map positions for these and other loci common to the linkage and cytogenetic maps. This work represents a major breakthrough for cytogenetic mapping of the maize genome, and also provides a general strategy that can be applied to cytogenetic mapping of other plant species with relatively large and complex genomes.