bluuebunny/crossref_metadata_2025_split huggingface dataset:
Loss of cell wall alpha(1‐3) glucan affects Cryptococcus neoformans from ultrastructure to virulence
Authors: Reese Amy J. , Yoneda Aki , Breger Julia A. , Beauvais Anne , Liu Hong , Griffith Cara L. , Bose Indrani , Kim Myoung‐Ju , Skau Colleen , Yang Sarah , Sefko Julianne A. , Osumi Masako , Latge Jean‐Paul , Mylonakis Eleftherios , Doering Tamara L. 
Published: January 2007

SummaryYeast cell walls are critical for maintaining cell integrity, particularly in the face of challenges such as growth in mammalian hosts. The pathogenic fungus Cryptococcus neoformans additionally anchors its polysaccharide capsule to the cell surface via α(1‐3) glucan in the wall. Cryptococcal cells disrupted in their alpha glucan synthase gene were sensitive to stresses, including temperature, and showed difficulty dividing. These cells lacked surface capsule, although they continued to shed capsule material into the environment. Electron microscopy showed that the alpha glucan that is usually localized to the outer portion of the cell wall was absent, the outer region of the wall was highly disorganized, and the inner region was hypertrophic. Analysis of cell wall composition demonstrated complete loss of alpha glucan accompanied by a compensatory increase in chitin/chitosan and a redistribution of beta glucan between cell wall fractions. The mutants were unable to grow in a mouse model of infection, but caused death in nematodes. These studies integrate morphological and biochemical investigations of the role of alpha glucan in the cryptococcal cell wall.
Shaping the Borrelia burgdorferi genome: crystal structure and binding properties of the DNA‐bending protein Hbb
Authors: Mouw Kent W. , Rice Phoebe A. 
Published: January 2007

SummaryThe genome of the Lyme disease‐causing spirochete Borrelia burgdorferi encodes only a single polypeptide from the integration host factor (IHF)/HU or ‘DNABII’ family of nucleoid‐associated proteins – Hbb. DNABII proteins induce large bends in DNA and serve as architectural factors in a variety of prokaryotic cellular processes. We have solved the crystal structure of an Hbb–DNA complex in which the DNA is bent by over 180°. We find that like IHF, Hbb relies exclusively on indirect readout to recognize its cognate site. Additional binding studies show that the sequence preferences of Hbb are related to, yet distinct from those of IHF. Defining these binding characteristics may help to uncover additional roles for Hbb in Borrelia DNA metabolism as well as further our understanding of the mechanism of indirect readout.
Plasmodium falciparum var gene expression is developmentally controlled at the level of RNA polymerase II‐mediated transcription initiation
Authors: Kyes Sue , Christodoulou Zóe , Pinches Robert , Kriek Neline , Horrocks Paul , Newbold Chris 
Published: January 2007

SummaryThe Plasmodium falciparum var gene family codes for a major virulence factor in this most lethal of human malaria parasites. A single var protein variant type is expressed on each infected red blood cell, with antigenic variation allowing progeny parasites to escape host immune detection. The control of mutually exclusive var gene expression in the parasite relies on in situ epigenetic changes. Whether control of expression occurs at transcription initiation or post transcription, however, remains to be established. Recent evidence supports existence of a unique var transcription site at the nuclear periphery containing the dominantly expressed var gene, although silent var genes can colocalize to the same region. We demonstrate here that exclusive var gene expression is controlled at the level of transcription initiation during ring stages and that var genes are transcribed by RNA polymerase II. This represents another example where P. falciparum differs from the paradigm for antigenic variation, Trypanosoma brucei.
Artificial regulation of ospC expression in Borrelia burgdorferi
Authors: Gilbert Michael A. , Morton Elizabeth A. , Bundle Sharyl F. , Samuels D. Scott 
Published: January 2007

SummaryOuter surface lipoprotein (Osp) C is a virulence factor required for transmission of the Lyme disease agent, Borrelia burgdorferi. We have constructed an inducible promoter system to study the function and regulation of OspC by integrating regulatory elements from the Escherichia coli lac operon into the B. burgdorferi genome. An inducible promoter (flacp) was constructed by inserting a synthetic lac operator sequence between the transcriptional start site and the ribosomal binding site of the B. burgdorferi flgB promoter; flacp was then used to replace the native ospC and rpoS promoters in B. burgdorferi derivatives that constitutively express the E. coli Lac repressor protein (LacI). In vitro, the expression of ospC and rpoS from flacp was dependent on the inducer isopropyl β‐D‐thiogalactopyranoside and was unaffected by temperature or pH, conditions commonly used to mimic different aspects of the B. burgdorferi life cycle. Our results suggest that OspC is essential immediately upon injection into a mouse and OspC expression must be maintained during the early stages of infection. In addition, the mouse infectivity experiment indicates that this system can be used to regulate B. burgdorferi genes in vivo, within the context of an experimental tick–mouse infectious cycle. RpoS is an alternative sigma factor that is required for ospC transcription. However, the role of other temperature‐dependent factors has not previously been addressed. Our results with the inducible rpoS strain demonstrate that RpoS alone is sufficient to activate OspC expression, even at 23°C. This is the first functional inducible promoter system developed for use in B. burgdorferi and, for the first time, will provide researchers with the ability to artificially regulate the expression of genes in this pathogenic spirochaete.
Cytokine expression in hamsters experimentally infected with Opisthorchis viverrini
Authors: JITTIMANEE J. , SERMSWAN R. W. , PUAPAIROJ A. , MALEEWONG W. , WONGRATANACHEEWIN S. 
Published: January 2007

SUMMARY The cytokine mRNA expression of IL‐12, IFN‐γ, TGF‐β, IL‐4, and IL‐10 were investigated in spleen, liver and mesenteric lymph nodes (MLN) in hamsters experimentally infected with Opisthorchis viverrini. Animals were infected with 5, 25 or 100 metacercariae (Mc) and examined by RT‐PCR and real‐time PCR at 2 weeks, 2 and 6 months after infection. The cytokine expression was compared using HPRT. The IL‐12 was significantly expressed at 2 weeks in the liver of the 5‐ and 25‐Mc‐infected groups. It is correlated with the inflammation intensity found in the liver at the same time. The production of IFN‐γ was not increased. The significant increase in expression of IL‐10 was observed in the 6‐month group in the spleen, which may suppress the Th1 and lead to a Th2 response. The IL‐4 and TGF‐β expressions in MLN were significantly increased, and correlated with the dose of infection, especially in the 6‐month groups. The TGF‐β level in MLN was 15‐fold higher than in the uninfected control, compared to a twofold increase in spleen and liver. Because this parasite resides in the bile duct, the regulatory cytokine levels of mucosal immunity were enhanced more than those in systemic immunity. These results indicate the predominance of Th2 responses in chronic O. viverrini infection, and the high level of TGF‐β may inhibit the immune functions, which allows the parasites to evade host immune response.
Lymphotoxin alpha and tumour necrosis factor are not required for control of parasite growth, but differentially regulate cytokine production during Plasmodium chabaudi chabaudi AS infection
Authors: CLARK K. , KULK N. , AMANTE F. , HAQUE A. , ENGWERDA C. 
Published: January 2007

SUMMARY Tumour necrosis factor (TNF) plays important roles in the pathogenesis of severe malaria, as well as in the generation of immune responses against malaria parasites. However, far less is known about the role of the closely related TNF family member lymphotoxin alpha (LTα) during malaria. We have used mice deficient in either TNF or LTα, as well as chimeric mice generated using donor bone marrow from these animals, to study the roles of these cytokines following Plasmodium chabaudi chabaudi AS infection. TNF and LTα were not required for the resolution of P. chabaudi chabaudi AS blood‐stage infection. However, LTα, but not TNF, was necessary for early IFNγ production and the regulation of IFNγ production later in infection. A similar delay to that found for IFNγ production was also observed for TNF production in LTα‐deficient mice, compared with control mice. These results identify divergent roles for TNF and LTα in the regulation of host immune responses during P. chabaudi chabaudi AS infection.
Immunization with recombinant beta‐tubulin from Trypanosoma evansi induced protection against T. evansi, T. equiperdum and T. b. brucei infection in mice
Authors: LI S.‐Q. , FUNG M.‐C. , REID S.A. , INOUE N. , LUN Z.‐R. 
Published: January 2007

SUMMARY The beta‐tubulin gene of Trypanosoma evansi (STIB 806) was cloned and expressed in Escherichia coli. The predicted amino acid sequence of T. evansi beta‐tubulin shows 100%, 99·8%, 99·1%, and 98·6% homology with T. equiperdum, T. b. brucei, T. cruzi and T. danilewskyi, respectively, but is diverse from that of T. cyclops, showing only 51·6% of homology. Recombinant beta‐tubulin was expressed as inclusion bodies in E. coli. It was purified and renatured for immunological studies. Mice immunized with the renatured recombinant beta‐tubulin were protected from lethal challenge with T. evansi STIB 806, T. equiperdum STIB 818 and T. b. brucei STIB 940, showing 83·3%, 70% and 76·7% protection, respectively. Serum collected from the rabbit immunized with recombinant beta‐tubulin inhibited the growth of T. evansi, T. equiperdum and T. b. brucei in vitro. Serum from mice and rabbits immunized with recombinant beta‐tubulin recognized only T. evansi beta‐tubulin and not mouse beta‐tubulin. The results of this study demonstrated that the recombinant T. evansi beta‐tubulin is a potential candidate for the development of a vaccine to prevent animal trypanosomiasis caused by these three trypanosome species.
Sulphite oxidase as key enzyme for protecting plants against sulphur dioxide
Authors: LANG CHRISTINA , POPKO JENNIFER , WIRTZ MARKUS , HELL RÜDIGER , HERSCHBACH CORNELIA , KREUZWIESER JÜRGEN , RENNENBERG HEINZ , MENDEL RALF R. , HÄNSCH ROBERT 
Published: January 2007

ABSTRACTSulphur dioxide (SO2) is known as a strongly damaging air pollutant. After conversion to sulphite in aqueous solution, it becomes a strong nucleophilic agent that attacks numerous compounds in the cell. Therefore, plants have developed a mechanism to control sulphite levels. Recently, we have cloned and characterized the enzyme sulphite oxidase (SO) from Arabidopsis thaliana. Yet, its physiological role remained unclear. Here, we describe results demonstrating that SO is essential for detoxifying excessive amounts of sulphite in the cell which is important for the survival of the plant. T‐DNA‐tagged A. thaliana plants lacking the enzyme showed a decrease in vitality during SO2 fumigation and a change in their S‐metabolites. The same was found with RNA‐interference (RNAi) plants that were generated for tobacco. On the contrary, over‐expression of SO helped the plant to survive SO2 concentrations that are detrimental for non‐transformed wild‐type (WT) plants, as was shown with poplar plants which are known to be particularly sensitive to SO2. Fumigation induced the expression of the enzyme as demonstrated by promoter–reporter gene fusion, by immunoblot analysis of SO‐protein and by induction of enzyme activity. This implies that SO, as an otherwise constitutively expressed protein, is under additional control by SO2 in the environment.
Increase in song frequency decreases spermatophore size: correlative evidence of a macroevolutionary trade‐off in katydids (Orthoptera: Tettigoniidae)
Authors: DEL CASTILLO R. C. , GWYNNE D. T. 
Published: January 2007

AbstractIn many katydids, the male feeds his mate with a large gelatinous spermatophore. Males of most species also produce elaborate calling songs. We predicted a negative relationship between spermatophore size and call frequency because of trade‐offs between these two costly traits. Our comparative analysis controlling phylogeny and body size supported this prediction. Although call frequency is expected to decrease with increasing body size, after controlling for phylogeny, both variables were not related. Finally, given that song frequency and spermatophore size are likely targets of sexual selection, we examined the relationship between these variables and sexual size dimorphism (SSD) which can be influenced by sexual selection on body size. We found that only female body size was positively related to SSD, suggesting that natural and/or sexual selection on female body size may be stronger than sexual selection on male and spermatophore size.
Transmission of the pine wood nematode Bursaphelenchus xylophilus through feeding activity of Monochamus galloprovincialis (Col., Cerambycidae)
Authors: Naves P. M. , Camacho S. , De Sousa E. M. , Quartau J. A. 
Published: January 2007

Abstract:  Transmission of the pinewood nematode (PWN) Bursaphelenchus xylophilus (Steiner & Bührer) Nickle to Pinus pinaster Aiton branches through feeding wounds of its vector in Portugal, Monochamus galloprovincialis Olivier, was studied under laboratory conditions. All the B. xylophilus‐infected beetles transmitted nematodes to branches they fed. The transmission was more frequent during the first 6 weeks after emergence, with transmission peaks during the second and the sixth week. The adult M. galloprovincialis transmitted nematodes for a mean of 5 weeks, independently of the beetle's sex or longevity. No relation was found between beetle feeding intensity and effective transmission of B. xylophilus to the branches. The nematode transmission ceased after the ninth week, even in insects which still had B. xylophilus on their bodies. The longevity of the nematode‐free insects (control group) was slightly higher than the B. xylophilus‐infected beetles, although with no significant difference. The results emphasize the necessity to control the immature stages of M. galloprovincialis prior to emergence and develop efficient strategies to capture and eliminate the recently emerged beetles, as majority of the nematode infection of healthy pine trees occurs during a short period of few weeks after beetle emergence.
Consideration of the determinants of women's mental health in remote Australian mining towns
Authors: Sharma Sanjay , Rees Susan 
Published: January 2007

Abstract Families in remote mining towns constitute a specific sociological group living under unique geographical and sociocultural circumstances. Isolation from friends and relatives and limited resources and opportunities for family members of mine workers are some of the distinct disadvantages of these towns. Decades ago it was observed that a large number of women in new and remote mining towns suffered from neurotic problems. In contemporary times there is a deficit of knowledge about the mental health of women in remote mining towns. However, there are certain indicators of significant mental distress among women living in these particular environments. Deriving from a review of literature, this paper explores various mining work‐related issues and sociocultural settings and processes within remote mining towns that could possibly exert coercive pressures on the psychological health of female partners of mine workers and their relationship well‐being. The paper suggests that work schedules and preponderance of men in mining jobs help promote a patriarchal culture within the community and the family; thereby marginalising women to a secondary status. Limited opportunities and resources within the community isolate women to domestic lives; while atypical work rosters associated with mining employment could negatively impact on the relationship well‐being of couples. The paper recommends that an inquiry into psychiatric well‐being among women of remote mining communities needs to consider the sociocultural structure and processes within these communities, and the structural nature of the mining job that could be responsible for role strain‐induced stress and mental health problems among these women.
Medical students and rural general practitioners: Congruent views on the reality of recruitment into rural medicine
Authors: Eley Diann , Young Louise , Shrapnel Marilyn , Wilkinson David , Baker Peter , Hegney Desley 
Published: January 2007

AbstractObjective:  In‐depth exploration of the perceptions, experiences and expectations of current long‐term rural GPs and medical students intent on a rural career, regarding the current and future state of rural medicine. Design:  Qualitative study using semistructured interviews. Setting:  Rural and remote towns in Central and Southern Queensland and the School of Medicine, University of Queensland. Participants:  Thirteen rural GPs with 10–40 years experience. Medical students (five second‐ and seven third‐year), all of whom are members of a rural students' club and have an intention to pursue rural practice. Interviews were conducted between August and December 2004. Main outcome measures:  Emergent themes relating to participant perceptions of the current and future state of rural medicine. Results:  Despite large differences in generation and experience, medical students and rural GPs hold similar perceptions and expectations regarding the current and future state of rural practice. In particular, they cite a lack of professional support at the systems level. This includes specific support for: continuing medical education to obtain and retain the skills necessary for rural practice; dealing with the higher risks associated with procedural work; and consequences of medico‐legal issues and workforce shortage issues such as long hours and availability of locums. Conclusions:  Issues relating to recruitment and retention of the rural health workforce are identified by both cohorts as relating to professional support. Medical schools and institutional support systems need to join forces and work together to make rural practice a viable career in medicine.
‘Shared Care – Shared Dream’: Model of shared care in rural Australia between mental health services and general practitioners
Authors: Samy D. Chinna , Hall Philip , Rounsevell Jacquie , Carr Rodney 
Published: January 2007

AbstractObjective:  To identify a working model between rural and remote mental health services and the local GPs in Australia. Design:  Postal questionnaire to assess the GPs' satisfaction level with the involvement of the mental health services in their ongoing management of mentally ill in the community. Result:  There was a greater sense of satisfaction with the mental health services over the five years this program was implemented. Conclusion:  This study offers a model on how a rural mental health service could enter into a shared care program with the local GP practice and achieve a greater level of satisfaction in serving the rural communities in Australia.
Reduced shear stress and disturbed flow may lead to coronary aneurysm and thrombus formations
Authors: OHKUBO TAKASHI , FUKAZAWA RYUJI , IKEGAMI EI , OGAWA SHUNICHI 
Published: January 2007

AbstractBackground: With Kawasaki disease it is important to clarify the mechanisms of coronary artery aneurysm and thrombus to avoid acute myocardial infarction. The authors tested the hypothesis that shear stress is reduced at coronary branching sites and in coronary artery aneurysms, and that this reduction of shear stress can promote formation of coronary artery aneurysms and thrombus.Methods: The subjects were 111 children with Kawasaki disease with left coronary artery aneurysms, classified into three groups: giant coronary artery aneurysm (n= 28, diameter of coronary artery >8 mm), aneurysm (n= 44, diameter of coronary artery =8 mm), and normal‐appearing coronary (n= 39). Averaged peak flow velocity (APV), flow patterns and shear stress were measured and calculated at normal‐appearing coronary vessels, left coronary artery branching sites and intra‐coronary aneurysm using flow wire, and coronary angiography. Also, presence and appearance of thrombus were detected by intravascular ultrasonography.Results: The authors found that 90.3% of the coronary artery aneurysms occurred at major left coronary branching sites. APV and shear stress were significantly decreased in giant coronary artery aneurysms (APV, 7.1 ± 2.1 cm/s; shear stress, 3.8 ± 2.1 dyne/cm2) and at the left coronary artery branching site (APV, 9.1 ± 1.2; shear stress, 1±±.2 3.0). In total, 20 of 24 thrombi were detected only in giant aneurysm, and all patients exhibited disturbed flow pattern in their giant coronary artery aneurysms.Conclusions: Reduced shear stress and disturbed flow pattern may lead to coronary artery aneurysm and thrombus formation.
Hypernatremic dehydration in the newborn period and long‐term follow up
Authors: ERGENEKON EBRU , UNAL SUNA , GÜCÜYENER KIVILCIM , SOYSAL S¸EBNEM , KOÇ ESI˙N , OKUMUS¸ NURULLAH , TÜRKYILMAZ CANAN , ONAL ESRA , ATALAY YILDIZ 
Published: January 2007

AbstractBackground: Hypernatremic dehydration due to inadequate fluid intake can be a significant problem during the neonatal period and thereafter. The objective of the present study was to evaluate the term newborn infants admitted to Gazi University Hospital neonatal intensive care unit (NICU) for hypernatremic dehydration between June 2001 and June 2003 and compare the results with those of the literature search performed via MEDLINE for infants with the same diagnosis.Methods: Infants with weight loss ≥10% were evaluated for hypernatremia and the ones with serum Na level ≥150 mEq/L were admitted to NICU. Long‐term follow‐up evaluations were performed using Bayley Scales of Infant Development I (BSID I) and Bayley Infant Neurodevelopmental Screener (BINS) tests.Results: Between June 2001 and June 2003, 28 newborns were admitted to NICU with hypernatremic dehydration. Literature review found 178 newborns with the same diagnosis since 1979 and detailed information was available for 150 patients. In the study and MEDLINE groups, respectively mean days of admission were 3.39 and 11.7; mean serum sodium, 156.5 and 178.6 mEq/L; and mean % weight loss, 11.5 and 25.7. Long‐term follow up was performed in 15 patients from the study group, and two patients were found to be severely neurologically delayed. Five patients were found to have moderate risk scores by BINS tests.Conclusions: Early follow‐up visits of newborns soon after discharge are important to determine risk for hypernatremic dehydration. Long‐term follow up of this group of babies is also required to gather knowledge about the repercussions of early hypernatremic dehydration later in life.