bluuebunny/crossref_metadata_2025_split huggingface dataset:
Refractive index‐based determination of detergent concentration and its application to the study of membrane proteins
Authors: Strop Pavel , Brunger Axel T. 
Published: July 2005

AbstractThe concentration of detergent in membrane protein preparations can have a critical role on protein stability, function, and the potential for crystallization. Unfortunately, dialysis or protein concentration can lead to an unknown amount of detergent in the final membrane protein preparations. Here we present a method for the determination of detergent concentration based on refractive index of the detergent solution. This method was applied to quantitate the amount of detergent remaining in solution after concentration in various concentrators. We found that the ability of the tested detergents to pass through the molecular weight cutoff membrane correlates well with detergent micelle size. Therefore, the micelle size can be used as a rough guide to estimate the retention of a given detergent in various molecular weight cutoff concentrators. The refractive index method is exceptionally informative when coupled with size exclusion chromatography and light scattering, and can be used to determine the oligomeric state of the membrane protein, the size of a protein‐associated micelle, as well as the amount and size of the unbound detergent micelle.
Three‐dimensional structure of the AAH26994.1 protein from Mus musculus, a putative eukaryotic Urm1
Authors: Singh Shanteri , Tonelli Marco , Tyler Robert C. , Bahrami Arash , Lee Min S. , Markley John L. 
Published: July 2005

AbstractWe have used NMR spectroscopy to determine the solution structure of protein AAH26994.1 from Mus musculus and propose that it represents the first three‐dimensional structure of a ubiquitin‐related modifier 1 (Urm1) protein. Amino acid sequence comparisons indicate that AAH26994.1 belongs to the Urm1 family of ubiquitin‐like modifier proteins. The best characterized member of this family has been shown to be involved in nutrient sensing, invasive growth, and budding in yeast. Proteins in this family have only a weak sequence similarity to ubiquitin, and the structure of AAH26994.1 showed a much closer resemblance to MoaD subunits of molybdopterin synthases (known structures are of three bacterial MoaD proteins with 14%–26% sequence identity to AAH26994.1). The structures of AAH26994.1 and the MoaD proteins each contain the signature ubiquitin secondary structure fold, but all differ from ubiquitin largely in regions outside of this fold. This structural similarity bolsters the hypothesis that ubiquitin and ubiquitin‐related proteins evolved from a protein‐based sulfide donor system of the molybdopterin synthase type.
Mutual paracrine effects of colorectal tumour cells and stromal cells: modulation of tumour and stromal cell differentiation and extracellular matrix component production in culture
Authors: Mukaratirwa Sydney , Koninkx Jos F. , Gruys Erik , Nederbragt Hubertus 
Published: July 2005

SummaryInteractions of tumour and stromal cells influence tumour cell proliferation and differentiation, stromal cell phenotypic transdifferentiation and secretion of extracellular matrix (ECM) components. In this study, we established a monolayer and a three‐dimensional cell‐to‐cell interaction model between canine mammary stromal cells and human colonic carcinoma cell lines (Caco‐2 and HT‐29) to investigate mutual paracrine effects of tumour cells and stromal cells on (i) tumour cell differentiation, (ii) production of ECM components and (iii) phenotypic transdifferentiation of stromal cells. We showed that when Caco‐2 or HT‐29 cells are cultured in collagen gels, they form a few small solid cell clusters with no lumina, but when cocultured with stromal cells, the tumour cells formed glandular structures with central lumina. This fibroblast‐induced organization and differentiation of Caco‐2 cells (not HT‐29 cells) appeared to be mediated by transforming growth factor‐β (TGF‐β). Culturing of stromal cells, Caco‐2 cells or HT‐29 cells alone in both monolayers and gels resulted in weak tenascin‐C expression in stromal cells and HT‐29 cells and no expression in the Caco‐2 cells. Coculturing of stromal cells with tumour cells resulted in increased tenascin‐C expression in the stromal cells and HT‐29 cells and induced expression of tenascin‐C in the Caco‐2 cells. This induction and increased expression of tenascin‐C appeared to be mediated by TGF‐β. Culturing of stromal cells, Caco‐2 cells or HT‐29 cells alone on monolayers and in gels resulted in a weak expression of chondroitin sulfate (CS), chondroitin‐6‐sulfate (C‐6‐S) and versican in stromal cells and no expression in Caco‐2 and HT‐29 cells. Coculturing of stromal cells with tumour cells on monolayers and in gels resulted in increased CS, C‐6‐S and versican expression in stromal cells. This tumour cell‐induced expression of CS, C‐6‐S and versican appeared to be mediated by TGF‐β and platelet‐derived growth factor (PDGF). Coculturing of Caco‐2 and HT‐29 and stromal cells promoted the transdifferentiation of stromal cells into myofibroblasts, and this appeared to be mediated by TGF‐β. These results suggest that TGF‐β and PDGF are part of a paracrine system involved in stromal–epithelial cell interaction important in stromal cell differentiation and ECM component production.
Dietary copper supplements modulate aortic superoxide dismutase, nitric oxide and atherosclerosis
Authors: Lamb David J. , Tickner Michelle L. , Hourani Susanna M. O. , Ferns Gordon A. A. 
Published: July 2005

SummaryThe objective was to test the hypothesis that dietary copper inhibits atherosclerosis by inducing superoxide dismutase (SOD) and potentiating nitric oxide (NO). New Zealand White rabbits were fed either a cholesterol diet (n = 8) or a cholesterol diet containing 0.02% copper acetate (n = 8) for 13 weeks. We found that the intimal area was significantly smaller in the animals supplemented with copper (P < 0.005), although integrated plasma cholesterol levels were not significantly different. This was associated with a significant increase in aortic copper content (P < 0.05), SOD activity (P < 0.05) and Cu/Zn SOD mRNA (P < 0.05) and a significant decrease in nitrotyrosine content (P < 0.05). Furthermore, there was a positive correlation between aortic copper content and SOD activity (P < 0.005,R2 = 0.83) and a negative correlation between aortic superoxide dimutase activity and nitrotyrosine content (P < 0.005,R2 = 0.93). In organ bath experiments, the relaxation of precontracted carotid artery rings to calcium ionophore was greater in animals supplemented with copper. No difference in response to sodium nitroprusside was observed. These data suggest that in the cholesterol‐fed rabbit, copper supplements inhibit the progression of atherosclerosis by increasing SOD expression, thereby reducing the interaction of NO with superoxide, and hence potentiating NO‐mediated pathways that may protect against atherosclerosis.
B‐1 cells are pivotal for in vivo inflammatory giant cell formation
Authors: Bogsan Cristina Stewart Bittencourt , Brito Ronni Rômulo Novaes e , Palos Maiko da Cruz , Mortara Renato Arruda , Almeida Sandro Rogério , Lopes José Daniel , Mariano Mario 
Published: July 2005

AbstractThe mechanisms that govern giant cell (GC) formation in inflammatory, neoplastic and physiologic conditions are far from being understood. Here, we demonstrate that B‐1 cells are essential for foreign‐body GC formation in the mouse. GCs were analysed on the surface of glass cover slips implanted into the subcutaneous tissue of the animals. It was demonstrated that GCs are almost absent on cover slips implanted into the subcutaneous tissue of BALB/c or CBA/N X‐linked immunodeficient mice. As these animals do not have B‐1 cells in the peritoneal cavity, they were reconstituted with B‐1 cells obtained from cultures of adherent mouse peritoneal cells. Results showed that in B‐1‐reconstituted animals, the number of GCs on the implant surface surpassed the values obtained with preparations from wild animals. In animals selectively irradiated (pleural and peritoneal cavities) to deplete these cavities of B‐1 cells, GCs were also not formed. Enriched suspensions of B‐1 cells grown in culture were labelled with [3H]‐tymidine and injected into the peritoneal cavity of naive mice before implantation of glass cover slips. After 4 days, about 17% of mononuclear cells had their nuclei labelled, and almost 70% of GCs had one or more of their nuclei labelled when analysed by histoautoradiographic technique. A few GCs expressed an immunoglobulin M when analysed by immunostaining and confocal microscopy. Overall, these data demonstrate that B‐1 cells are pivotal in the mechanisms of foreign‐body GC formation in the mouse.
Strategic Supply Management and Dyadic Quality Performance: A Path Analytical Model
Authors: Paulraj Antony , Chen Injazz J. 
Published: July 2005

SummaryA number of studies have addressed the critical role of strategic purchasing and its impact on buyer–supplier relationships. Most studies, however, treat buyer–supplier relationships as a single construct. Recognizing that buyer–supplier relationships are a much more complex phenomenon, this study first identifies three critical constructs including supply base reduction, communication and long‐term relationships for a broader conceptualization of buyer–supplier relationships. It then explores the effects of strategic purchasing on these three constructs, along with their impacts on dyadic quality performance. The proposed path analytical model was tested using structural equation modeling. Results provide robust support for the notion that strategic supply management improves the quality performance of both supplier and buyer firms.
Supply Management Strategies for the Future: A Delphi Study
Authors: Ogden Jeffrey A. , Petersen Kenneth J. , Carter Joseph R. , Monczka Robert M. 
Published: July 2005

SummaryAs supply management becomes more involved in strategic decisions, an understanding of the various strategies that it can employ is crucial. This research uses a multiround Delphi study of key procurement and supply management executives to better understand which procurement and supply management strategies may lead to significant improvements over the next 5–10 years. The results indicate that strategies such as increased integration, information sharing and collaboration among supply chain members are most likely to be implemented and will have the largest impact on organizations. However, this integration will not include joint investment or asset sharing, will be limited to one tier in the supply chain, and will not heavily involve e‐markets and electronic auctions.
CREM activator and repressor isoform expression in human male germ cells
Authors: BLÖCHER SONJA , FINK LUDGER , BOHLE RAINER M. , BERGMANN MARTIN , STEGER KLAUS 
Published: July 2005

SummaryThe transcription factor cAMP‐responsive element modulator (CREM) is known to play a vital role for male fertility as it has been demonstrated that male mice lacking a functional CREM gene are infertile. The CREM gene consists of 14 exons. Owing to alternative exon splicing, CREM gene expression results in the production of functionally different CREM proteins with either activating or repressing potential on target gene expression. Infertile men have been reported to reveal a substantial reduction of CREM activators and additional inaccurately spliced CREM transcripts. In the present study, we analysed the expression of CREM transcripts with the recently reported leader exons θ1 and θ2 and identified a new putative CREM repressor, namely θ1‐F‐H, in patients with impaired spermatogenesis. In addition, we applied single cell microdissection followed by RT‐PCR with leader exons B, θ1 and θ2 to assign the expressed CREM activator and repressor isoforms to specific germ cell types within the seminiferous epithelium. Contrary to dogma, we demonstrated CREM activator and repressor isoforms in all germ cell types, but not in Sertoli cells. However, the percentage of germ cell samples that revealed positive RT‐PCR signals for these CREM activators was higher in spermatocytes and round spermatids than in spermatogonia and elongated spermatids. It remains unknown whether these activator transcripts are physiologically active. Our data suggest a fine‐tuning between CREM activator and repressor isoforms in normal germ cells that might be disturbed during impaired spermatogenesis.
Altered melatonin secretion in hypogonadal men: clinical evidence
Authors: KUMANOV PHILIP , TOMOVA ANALIA , ISIDORI ALDO , NORDIO MAURIZIO 
Published: July 2005

SummaryThe pineal gland, through the rhythmic production of melatonin, seems to play an important role in the control of the reproductive function of many vertebrate species. In contrast, the effects of the pineal gland in humans and the relationship between gonadotropins and melatonin secretion are not yet clarified. On the basis of these considerations, the aim of the present study was to clarify whether melatonin serum concentrations were altered in males with different hypothalamo‐pituitary–gonadal disturbances, in comparison to normal individuals.We have studied 36 individuals divided into three groups according to their gonadotropin status: normals, hypogonadotropic hypogonadism and hypergonadotropic hypogonadism. They were submitted to blood sample withdrawal at 03.00, 11.00 and 19.00 h for melatonin determination according to a radioimmunological method, without extraction of the sample.The results obtained in the present study suggest the existence of an interaction between the pituitary and the pineal gland. In fact, in the case of hypersecretion of gonadotropins, nocturnal melatonin release is reduced, while night melatonin secretion is increased in the opposite situation (hypogonadotropic hypogonadism). Both these endocrine pathologies are characterized by a reduced sexual steroid secretion; for that reason, this reduction cannot be regarded as responsible for the two opposite dysfunctions of melatonin release.In conclusion, our study shows that darkness‐dependent release of melatonin in males with hypogonadotropic hypogonadism is significantly higher in comparison with the healthy men, while it is significantly reduced in patients with hypergonadotropic hypogonadism. A strong significant negative correlation is also found between gonadotropins and melatonin release.
The cryptorchidism prevalence among infants in the general population of Rotterdam, the Netherlands
Authors: PIERIK FRANK H. , BURDORF ALEX , KEIZER‐SCHRAMA SABINE M. P. F. DE MUINCK , WOLFFENBUTTEL KATJA P. , RIEN NIJMAN J. M. , JUTTMANN RIKARD E. , WEBER ROBERTUS F. A. 
Published: July 2005

SummaryPublished trends and geographical differences in cryptorchidism rates are almost exclusively derived from hospital‐based birth defect registers, which are sensitive to selection bias and incomplete reporting. This study aimed to accurately assess the cryptorchidism prevalence in the general population of Rotterdam. Of 7652 consecutive male live births, 7292 (95%) were examined for cryptorchidism at Child Healthcare Centres around the age of 1 month. In a subgroup of cases, the persistence of cryptorchidism was re‐assessed during a follow‐up examination by expert specialists. The cryptorchidism rate at the median age of 35 days was 1.2% (89/7292). In the re‐examined subgroup (median age 95 days) 69% of the boys (24/35) had persistent cryptorchidism, of which 20 were unilateral and four bilateral. The population rate of 1.2% falls within the range of 0.9–9% reported by others. Differences in case ascertainment and population characteristics probably explain part of the differences between studies. Our cross‐sectional design does not allow for analysis of a temporal trend, but provides a baseline for future trend studies. To study cryptorchidism rates, trends, and risk factors, a systematic case ascertainment is warranted.
Human mtDNA haplogroups and reduced male fertility: real association or hidden population substructuring
Authors: PEREIRA LUÍSA , GONÇALVES JOÃO , GOIOS ANA , ROCHA TIAGO , AMORIM ANTÓNIO 
Published: July 2005

SummaryA mitochondrial DNA (mtDNA) haplogroup association study carried out in 101 southern Portuguese males with oligozoospermia showed to be negative when comparing with a geographically matching control sample. Misleading positive association signs were however obtained when using other control samples from the same country. This shows that mtDNA population substructure can also introduce spurious signs in haplogroup association studies, as previously reported for Y‐chromosome. However, our data do not exclude the probability that a particular mtDNA mutation contributes significantly to the reduction of sperm production, but indeed precludes the hypothesis of a significant association between such a mutation and specific haplogroup.
Biochemical Characterisation and Immunohistochemical Localisation of the Secretogranin II‐Derived Peptide EM66 in the Hypothalamus of the Jerboa (Jaculus orientalis): Modulation by Food Deprivation
Authors: Boutahricht M. , Guillemot J. , Montero‐Hadjadje M. , Bellafqih S. , El Ouezzani S. , Alaoui A. , Yon L. , Vaudry H. , Anouar Y. , Magoul R. 
Published: July 2005

AbstractThe neuroendocrine protein secretogranin II is the precursor of several neuropeptides, including secretoneurin and a novel 66‐amino acid peptide, EM66, the sequence of which has been highly conserved across the vertebrae phylum. The presence of EM66 has been detected in the adult and fetal human adrenal gland, as well as the rat pituitary and adrenal glands. The present study aimed to explore a possible neuroendocrine role of EM66 by analysing its occurrence and distribution within the jerboa hypothalamus, and its potential implication in the control of feeding behaviour. High‐performance liquid chromatography analysis of jerboa hypothalamic extracts combined with a radioimmunoassay of EM66 revealed a single peak of immunoreactive material exhibiting the same retention time as recombinant EM66. Immunocytochemical labelling showed that EM66‐producing neurones are widely distributed in several hypothalamic regions, including the preoptic area, the suprachiasmatic, supraoptic, parvocellular paraventricular and arcuate nuclei, and the lateral hypothalamus. Food deprivation for 5 days induced a significant increase in the number of EM66‐containing neurones within the arcuate nucleus (105% increase) and the parvocellular aspect of the paraventricular nucleus (115% increase), suggesting that EM66 could be involved in the control of feeding behaviour and/or the response to stress associated with fasting. Altogether, these data reveal the physiological plasticity of the EM66 system in the hypothalamus and implicate this novel peptide in the regulation of neuroendocrine functions.
Arcuate Nucleus Transcriptome Profiling Identifies Ankyrin Repeat and Suppressor of Cytokine Signalling Box‐Containing Protein 4 as a Gene Regulated by Fasting in Central Nervous System Feeding Circuits
Authors: Li J.‐Y. , Kuick R. , Thompson R. C. , Misek D. E. , Lai Y.‐M. , Liu Y.‐Q. , Chai B.‐X. , Hanash S. M. , Gantz I. 
Published: July 2005

AbstractThe arcuate nucleus of the hypothalamus is a primary site for sensing blood borne nutrients and hormonal messengers that reflect caloric status. To identify novel energy homeostatic genes, we examined RNA extracts from the microdissected arcuate nucleus of fed and 48‐h fasted rats using oligonucleotide microarrays. The relative abundance of 118 mRNA transcripts was increased and 203 mRNA transcripts was decreased during fasting. One of the down‐regulated mRNAs was ankyrin‐repeat and suppressor of cytokine signalling box‐containing protein 4 (Asb‐4). The predicted structure of Asb‐4 protein suggested that it might encode an intracellular regulatory protein, and therefore its mRNA expression was investigated further. Reverse transcription quantitative polymerase chain reaction was used to validate down‐regulation of Asb‐4 mRNA in the arcuate nucleus of the fasted Sprague‐Dawley rat (relative expression of Asb‐4 mRNA: fed = 4.66 ± 0.26; fasted = 3.96 ± 0.23; n = 4, P < 0.01). Down‐regulation was also demonstrated in the obese fa/fa Zucker rat, another model of energy disequilibrium (relative expression of Asb‐4 mRNA: lean Zucker = 3.91 ± 0.32; fa/fa = 2.93 ± 0.26; n = 5, P < 0.001). In situ hybridisation shows that Asb‐4 mRNA is expressed in brain areas linked to energy homeostasis, including the arcuate nucleus, paraventricular nucleus, dorsomedial nucleus, lateral hypothalamus and posterodorsal medial amygdaloid area. Double in situ hybridisation revealed that Asb‐4 mRNA colocalises with key energy homeostatic neurones. In the fed state, Asb‐4 mRNA is expressed by 95.6% of pro‐opiomelanocortin (POMC) neurones and 46.4% of neuropeptide Y (NPY) neurones. By contrast, in the fasted state, the percentage of POMC neurones expressing Asb‐4 mRNA drops to 73.2% (P < 0.001). Moreover, the density of Asb‐4 mRNA per fasted POMC neurone is markedly decreased. Conversely, expression of Asb‐4 mRNA by NPY neurones in the fasted state is modestly increased to 52.7% (P < 0.05). Based on its differential expression, neuroanatomical distribution and colocalisation, we hypothesise that Asb‐4 is a gene involved in energy homeostasis.
Distribution analyses of Meloidogyne spp. and Pratylenchus coffeae sensu lato in coffee plots in Costa Rica and Guatemala
Authors: Herve G. , Bertrand B. , Villain L. , Licardie D. , Cilas C. 
Published: July 2005

The distribution of the plant‐parasitic nematodes Pratylenchus coffeae sensu lato and Meloidogyne spp. were studied in two plots, one in Guatemala (P. coffeae and M. paranaensis) and the other in Costa Rica (P. coffeae and M. exigua). The quantity of nematodes per g fresh weight root were counted for each coffee tree sampled. The distributions were aggregated, and generally fitted well to negative binomial distributions. Population aggregation was greater when a smaller number of nematodes were involved, suggesting that initial colonization develops in foci. Analyses of the relationships between population levels of the species suggested that there was competition between Pratylenchus coffeae and Meloidogyne spp. This competition was expressed differently depending on the relative population density of the different species.
Systemic Potato virus YNTN infection and levels of salicylic and gentisic acids in different potato genotypes
Authors: Krečič‐Stres H. , Vučak C. , Ravnikar M. , Kovač M. 
Published: July 2005

Endogenous levels of free and conjugated salicylic (SA) and gentisic (GA) acids, both putative signal molecules in plant defence, were analysed in order to investigate their involvement in the resistance of four potato (Solanum tuberosum) genotypes with different susceptibilities to Potato virus YNTN (PVYNTN) infection: the highly susceptible cv. Igor and its extremely resistant transgenic line, the extremely resistant cv. Sante and the tolerant cv. Pentland Squire. The lowest levels of free and conjugated SA were observed in the extremely resistant cv. Sante, while free GA, which was detected in all the other varieties, was absent. The extremely resistant transgenic cv. Igor contained the highest basal total SA level and the lowest level of total GA of all four cultivars. In susceptible cv. Igor, but not in resistant transgenic cv. Igor, a systemic increase of free SA was measured 1 day postinfection (dpi). Even more significant increases of free and conjugated SA and GA were detected 11 dpi when systemic symptoms appeared. In inoculated but not in upper noninoculated leaves of resistant transgenic cv. Igor, significant increase of SA conjugates occurred, but not before 11 dpi. The increase of SA and GA in susceptible cv. Igor could contribute to the general elevated levels of phenolic compounds as a response to stress caused by virus infection. It appears that basal levels of SA and GA do not correlate with resistance to PVYNTN in potato plants.