bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional analysis of NsrR, a nitric oxide‐sensing Rrf2 repressor in Neisseria gonorrhoeae
Authors: Isabella Vincent M. , Lapek Jr John D. , Kennedy Edward M. , Clark Virginia L. 
Published: November 2008

SummaryNitric oxide (NO) has been shown to be an important component of the human immune response, and as such, it is important to understand how pathogenic organisms respond to its presence. In Neisseria gonorrhoeae, recent work has revealed that NsrR, an Rrf2‐type transcriptional repressor, can sense NO and control the expression of genes responsible for NO metabolism. A highly pure extract of epitope‐tagged NsrR was isolated and mass spectroscopic analysis suggested that the protein contained a [2Fe−2S] cluster. NsrR/DNA interactions were thoroughly analysed in vitro. Using EMSA analysis, NsrR::FLAG was shown to interact with predicted operators in the norB, aniA and nsrR upstream regions with a Kd of 7, 19 and 35 nM respectively. DNase I footprint analysis was performed on the upstream regions of norB and nsrR, where NsrR was shown to protect the predicted 29 bp binding sites. The presence of exogenously added NO inhibited DNA binding by NsrR. Alanine substitution of C90, C97 or C103 in NsrR abrogated repression of norB::lacZ and inhibited DNA binding, consistent with their presumed role in co‐ordination of a NO‐sensitive Fe–S centre required for DNA binding.
Synchronous replication initiation in novel Mycobacterium tuberculosis dnaA cold‐sensitive mutants
Authors: Nair Naveen , Dziedzic Renata , Greendyke Rebecca , Muniruzzaman Syed , Rajagopalan Malini , Madiraju Murty V. 
Published: November 2008

SummaryThe genetic aspects of oriC replication initiation in Mycobacterium tuberculosis are largely unknown. A two‐step genetic screen was utilized for isolating M. tuberculosis dnaA cold‐sensitive (cos) mutants. First, a resident plasmid expressing functional dnaA integrated at the attB locus in dnaA null background was exchanged with an incoming plasmid bearing a mutagenized dnaA gene. Next, the mutants that were defective for growth at 30°C, a non‐permissive temperature, but resumed growth and DNA synthesis when shifted to 37°C, a permissive temperature, were subsequently selected. Nucleotide sequencing analysis located mutations to different regions of the dnaA gene. Modulation of the growth temperatures led to synchronized DNA synthesis. The dnaA expression under synchronized DNA replication conditions continued to increase during the replication period, but decreased thereafter reflecting autoregulation. The dnaAcos mutants at 30°C were elongated suggesting that they may possibly be blocked during the cell division. The DnaA115 protein is defective in its ability to interact with ATP at 30°C, but not at 37°C. Our results suggest that the optimal cell cycle progression and replication initiation in M. tuberculosis requires that the dnaA promoter remains active during the replication period and that the DnaA protein is able to interact with ATP.
Candida albicans cell surface superoxide dismutases degrade host‐derived reactive oxygen species to escape innate immune surveillance
Authors: Frohner Ingrid E. , Bourgeois Christelle , Yatsyk Kristina , Majer Olivia , Kuchler Karl 
Published: November 2008

SummaryMammalian innate immune cells produce reactive oxygen species (ROS) in the oxidative burst reaction to destroy invading microbial pathogens. Using quantitative real‐time ROS assays, we show here that both yeast and filamentous forms of the opportunistic human fungal pathogen Candida albicans trigger ROS production in primary innate immune cells such as macrophages and dendritic cells. Through a reverse genetic approach, we demonstrate that coculture of macrophages or myeloid dendritic cells with C. albicans cells lacking the superoxide dismutase (SOD) Sod5 leads to massive extracellular ROS accumulation in vitro. ROS accumulation was further increased in coculture with fungal cells devoid of both Sod4 and Sod5. Survival experiments show that C. albicans mutants lacking Sod5 and Sod4 exhibit a severe loss of viability in the presence of macrophages in vitro. The reduced viability of sod5Δ/Δ and sod4Δ/Δsod5Δ/Δ mutants relative to wild type is not evident with macrophages from gp91phox−/− mice defective in the oxidative burst activity, demonstrating a ROS‐dependent killing activity of macrophages targeting fungal pathogens. These data show a physiological role for cell surface SODs in detoxifying ROS, and suggest a mechanism whereby C. albicans, and perhaps many other microbial pathogens, can evade host immune surveillance in vivo.
Involvement of OsSPX1 in phosphate homeostasis in rice
Authors: Wang Chuang , Ying Shan , Huang Hongjie , Li Kuan , Wu Ping , Shou Huixia 
Published: November 2008

Summary Arabidopsis thaliana SPX (SYG/PHO81/XPR1) domain genes have recently been shown to be involved in the phosphate (Pi) signaling pathway. We show here that a rice (Oryza sativa) SPX gene, OsSPX1, is specifically induced by Pi starvation in roots. Suppression of OsSPX1 by RNA interference resulted in severe signs of toxicity caused by the over‐accumulation of Pi, similar to that found in OsPHR2 (phosphate starvation response transcription factor 2) overexpressors and pho2 (phosphate‐responsive mutant 2). Quantitative RT‐PCR showed that expression of OsSPX1 was strongly induced in OsPHR2 overexpression and pho2 mutant plants, indicating that OsSPX1 occurs downstream of OsPHR2 and PHO2. The expression of 10 genes associated with the phosphate‐starvation signal pathways was analyzed. Expression of OsPT2 (phosphate transporter 2) and OsPT8 was significantly induced in OsSPX1‐RNAi (OsSPX1‐Ri) plants, suggesting that over‐accumulation of Pi in OsSPX1‐Ri plants results from an increase in Pi transport. In contrast, overexpression of OsSPX1 suppressed the induction of expression by Pi starvation of all 10 phosphate starvation‐induced genes tested: IPS1 (induced by phosphate starvation 1), IPS2, OsPAP10 (purple acid phosphatase 10), OsSQD2 (sulfoquinovosyldiacylglycerol 2), miR399d and miR399j (microRNA 399), OsPT2, OsPT3, OsPT6 and OsPT8. This suggests that OsSPX1 acts via a negative feedback loop to optimize growth under phosphate‐limited conditions.
Both the conserved GRAS domain and nuclear localization are required for SHORT‐ROOT movement
Authors: Gallagher Kimberly L. , Benfey Philip N. 
Published: November 2008

SummaryTranscription factor movement is well established in plants. Since the initial report of KNOTTED movement, more than a dozen transcription factors have been shown to move in plants. However, the developmental significance of movement is not known. Using the SHORT‐ROOT (SHR) transcription factor as a tool for studying cell‐to‐cell trafficking, we show that movement of SHR from its site of synthesis is necessary for normal development of the Arabidopsis root. We identify multiple regions of SHR that are required for intra‐ and intercellular movement of SHR, including a region that is necessary for movement but not activity. We made the surprising discovery that the capacity for intercellular movement may be conserved among other GRAS family proteins. Finally, we provide evidence that movement requires both cytoplasmic and nuclear localization, strongly suggesting a mechanistic link between nuclear transport and cell‐to‐cell movement.
RKP, a RING finger E3 ligase induced by BSCTV C4 protein, affects geminivirus infection by regulation of the plant cell cycle
Authors: Lai Jianbin , Chen Hao , Teng Kunling , Zhao Qingzhen , Zhang Zhonghui , Li Yin , Liang Liming , Xia Ran , Wu Yaorong , Guo Huishan , Xie Qi 
Published: November 2008

SummaryThe C4 protein fromCurtovirusis known as a major symptom determinant, but the mode of action of the C4 protein remains unclear. To understand the mechanism of involvement of C4 protein in virus–plant interactions, we introduced theC4gene fromBeet severe curly top virus(BSCTV) into Arabidopsis under a conditional expression promoter; the resulting overexpression ofBSCTV C4led to abnormal host cell division. RKP, a RING finger protein, which is a homolog of the human cell cycle regulator KPC1, was discovered to be induced by BSCTV C4 protein. Mutation ofRKPreduced the susceptibility to BSCTV in Arabidopsis and impaired BSCTV replication in plant cells. Callus formation is impaired inrkpmutants, indicating a role of RKP in the plant cell cycle. RKP was demonstrated to be a functional ubiquitin E3 ligase and is able to interact with cell‐cycle inhibitor ICK/KRP proteinsin vitro. Accumulation of the protein ICK2/KRP2 was found increased in therkpmutant. The above results strengthen the possibility that RKP might regulate the degradation of ICK/KRP proteins. In addition, the protein level of ICK2/KRP2 was decreased upon BSCTV infection. Overexpression ofICK1/KRP1in Arabidopsis could reduce the susceptibility to BSCTV. In conclusion, we found thatRKPis induced by BSCTV C4 and may affect BSCTV infection by regulating the host cell cycle.
MERISTEM‐DEFECTIVE, an RS domain protein, is required for the correct meristem patterning and function in Arabidopsis
Authors: Casson Stuart A. , Topping Jennifer F. , Lindsey Keith 
Published: November 2008

SummaryPlant growth and development is dependent on the specification and maintenance of pools of stem cells found in the meristems. Mutations in the Arabidopsis MERISTEM‐DEFECTIVE (MDF) gene lead to a loss of stem cell and meristematic activity in the root and vegetative shoot. MDF encodes a putative RS domain protein with a predicted role in transcription or RNA processing control. mdf mutants exhibit decreased levels of PINFORMED2 (PIN2) and PIN4 mRNAs, which is associated with a reduction in PIN:GFP levels, and with a defective auxin maximum in the basal region of the developing mdf embryo and seedling root meristem. Seedling roots also exhibit reduced PLETHORA (PLT), SCARECROW and SHORTROOT gene expression, a loss of stem cell activity, terminal differentiation of the root meristem and defective cell patterning. MDF expression is not defective in the bodenlos, pin1 or eir1/pin2 auxin mutants, and is not modulated by exogenous auxin. plt1 plt2 double mutants have unaffected levels of MDF RNA, indicating that MDF acts upstream of PIN and PLT gene expression. Differentiation of the shoot stem cell pool also occurs in mdf mutants, associated with a reduced WUSCHEL (WUS) expression domain and expanded CLAVATA3 (CLV3) domain. Overexpression of MDF leads to the activation of markers of embryonic identity and ectopic meristem activity in vegetative tissues. These results demonstrate a requirement for the MDF‐dependent pathway in regulating PIN/PLT‐ and WUS/CLV‐mediated meristem activity.
EZ‐Rhizo: integrated software for the fast and accurate measurement of root system architecture
Authors: Armengaud Patrick , Zambaux Kevin , Hills Adrian , Sulpice Ronan , Pattison Richard J. , Blatt Michael R. , Amtmann Anna 
Published: November 2008

SummaryThe root system is essential for the growth and development of plants. In addition to anchoring the plant in the ground, it is the site of uptake of water and minerals from the soil. Plant root systems show an astonishing plasticity in their architecture, which allows for optimal exploitation of diverse soil structures and conditions. The signalling pathways that enable plants to sense and respond to changes in soil conditions, in particular nutrient supply, are a topic of intensive research, and root system architecture (RSA) is an important and obvious phenotypic output. At present, the quantitative description of RSA is labour intensive and time consuming, even using the currently available software, and the lack of a fast RSA measuring tool hampers forward and quantitative genetics studies. Here, we describe EZ‐Rhizo: a Windows‐integrated and semi‐automated computer program designed to detect and quantify multiple RSA parameters from plants growing on a solid support medium. The method is non‐invasive, enabling the user to follow RSA development over time. We have successfully applied EZ‐Rhizo to evaluate natural variation in RSA across 23 Arabidopsis thaliana accessions, and have identified new RSA determinants as a basis for future quantitative trait locus (QTL) analysis.
Dynamic organization of COPII coat proteins at endoplasmic reticulum export sites in plant cells
Authors: Hanton Sally L. , Matheson Loren A. , Chatre Laurent , Brandizzi Federica 
Published: November 2008

SummaryProtein export from the endoplasmic reticulum (ER) is mediated by the accumulation of COPII proteins such as Sar1, Sec23/24 and Sec13/31 at specialized ER export sites (ERES). Although the distribution of COPII components in mammalian and yeast systems is established, a unified model of ERES dynamics has yet to be presented in plants. To investigate this, we have followed the dynamics of fluorescent fusions to inner and outer components of the coat, AtSec24 and AtSec13, in three different plant model systems: tobacco and Arabidopsis leaf epidermis, as well as tobacco BY‐2 suspension cells. In leaves, AtSec24 accumulated at Golgi‐associated ERES, whereas AtSec13 showed higher levels of cytosolic staining compared with AtSec24. However, in BY‐2 cells, both AtSec13 and AtSec24 labelled Golgi‐associated ERES, along with AtSec24. To correlate the distribution of the COPII coat with the dynamics of organelle movement, quantitative live‐cell imaging analyses demonstrated that AtSec24 and AtSec13 maintained a constant association with Golgi‐associated ERES, irrespective of their velocity. However, recruitment of AtSec24 and AtSec13 to ERES, as well as the number of ERES marked by these proteins, was influenced by export of membrane cargo proteins from the ER to the Golgi. Additionally, the increased availability of AtSec24 affected the distribution of AtSec13, inducing recruitment of this outer COPII coat component to ERES. These results provide a model that, in plants, protein export from the ER occurs via sequential recruitment of inner and outer COPII components to form transport intermediates at mobile, Golgi‐associated ERES.
Arabidopsis mitogen‐activated protein kinase MPK12 interacts with the MAPK phosphatase IBR5 and regulates auxin signaling
Authors: Lee Jin Suk , Wang Shucai , Sritubtim Somrudee , Chen Jin‐Gui , Ellis Brian E. 
Published: November 2008

SummaryMitogen‐activated protein kinase (MAPK) phosphatases are important negative regulators in the MAPK signaling pathways responsible for many essential processes in plants, including development, stress management and hormonal responses. A mutation in INDOLE‐3‐BUTYRIC ACID‐RESPONSE5 (IBR5), which is predicted to encode a dual‐specificity MAPK phosphatase, was previously reported to confer reduced sensitivity to auxin and ABA in Arabidopsis roots. To further characterize IBR5, and to understand how it might help integrate MAPK cascades with hormone signaling, we searched for IBR5‐interacting MAPKs. Yeast two‐hybrid assays, in vitro binding assays and in vivo protein co‐immunoprecipitation studies demonstrated that MPK12 and IBR5 are physically coupled. The C‐terminus of MPK12 appears to be essential for its interaction with IBR5, and in vitro dephosphorylation and immunocomplex kinase assays indicated that activated MPK12 is efficiently dephosphorylated and inactivated by IBR5. MPK12 and IBR5 mRNAs are both widely expressed across Arabidopsis tissues, and at the subcellular level each protein is predominantly localized in the nucleus. In transgenic plants with reduced expression of the MPK12 gene, root growth is hypersensitive to exogenous auxins, but shows normal ABA sensitivity. MPK12 suppression in an ibr5 background partially complements the ibr5 auxin‐insensitivity phenotype. Our results demonstrate that IBR5 is a bona fide MAPK phosphatase, and suggest that MPK12 is both a physiological substrate of IBR5 and a novel negative regulator of auxin signaling in Arabidopsis.
Extracellular transport and integration of plant secretory proteins into pathogen‐induced cell wall compartments
Authors: Meyer Dorit , Pajonk Simone , Micali Cristina , O’Connell Richard , Schulze‐Lefert Paul 
Published: November 2008

SummaryMany fungal parasites enter plant cells by penetrating the host cell wall and, thereafter, differentiate specialized intracellular feeding structures, called haustoria, by invagination of the plant’s plasma membrane. Arabidopsis PEN gene products are known to act at the cell periphery and function in the execution of apoplastic immune responses to limit fungal entry. This response underneath fungal contact sites is tightly linked with the deposition of plant cell wall polymers, including PMR4/GSL5‐dependent callose, in the paramural space, thereby producing localized wall thickenings called papillae. We show that powdery mildew fungi specifically induce the extracellular transport and entrapment of the fusion protein GFP–PEN1 syntaxin and its interacting partner monomeric yellow fluorescent protein (mYFP)–SNAP33 within the papillary matrix. Remarkably, PMR4/GSL5 callose, GFP–PEN1, mYFP–SNAP33, and the ABC transporter GFP–PEN3 are selectively incorporated into extracellular encasements surrounding haustoria of the powdery mildew Golovinomyces orontii, suggesting that the same secretory defense responses become activated during the formation of papillae and haustorial encasements. This is consistent with a time‐course analysis of the encasement process, indicating that these extracellular structures are generated through the extension of papillae. We show that PMR4/GSL5 callose accumulation in papillae and haustorial encasements occurs independently of PEN1 syntaxin. We propose a model in which exosome biogenesis/release serves as a common transport mechanism by which the proteins PEN1 and PEN3, otherwise resident in the plasma membrane, together with membrane lipids, become stably incorporated into both pathogen‐induced cell wall compartments.
Nodular vasculitis in systemic lupus erythematosus
Authors: Westers‐Attema Annet , Van Tubergen A. , Plasschaert H. , Van Marion A. M. W. , Frank J. , Poblete‐Gutiérrez P. 
Published: November 2008

AbstractA 42‐year‐old man presented with fever, photosensitivity, headaches, myalgia, hyperhidrosis, muscle weakness, alopecia, nasal crustae, weight loss, painful nails, arthritis, oral ulcers, erythema, discoid cutaneous lesions, and painful subcutaneous nodes. We made a diagnosis of systemic lupus erythematosus (SLE), type II cryoglobulinemia, and nodular vasculitis. In the skin, different types of vasculitis may be observed. Typically, histology shows leukocytoclastic vasculitis of superficial vessels both in SLE and mixed cryoglobulinemia, which clinically results in palpable purpura. In our patient, however, histopathological examination of the subcutaneous nodes not only revealed leukocytoclastic vasculitis of the superficial vasculature but also showed even more extensive involvement of dermal and subdermal small and medium sized vessels, giving rise to a nodular vasculitis.
Penile pyoderma gangrenosum: successful treatment with colchicine
Authors: Parren Lizelotte J. M. T. , Nellen Ruud G. L. , Van Marion Arienne M. W. , Henquet Charles J. M. , Frank Jorge , Poblete‐Gutiérrez Pamela 
Published: November 2008

AbstractPyoderma gangrenosum is an ulcerative skin disease with variable clinical outcomes. The diagnosis is based on clinical features and exclusion of other ulcerative diseases. To date, a specific treatment is not known. Since the disease can be destructive, aggressive treatment is preferable. Here, we present a patient with a penile pyoderma gangrenosum who was successfully treated with low‐dose colchicine.
Neonatal Langerhans’ cell histiocytosis: a rare and potentially life‐threatening disease
Authors: Mosterd Klara , Van Marion Arienne , Van Steensel Maurice A. M. 
Published: November 2008

AbastractA 5‐day‐old girl presented with thrombocytopenia, leukopenia, anemia and crusted purpura on the skin. The diagnosis Langerhans’ cell histiocytosis (LCH) was suspected on clinical grounds and subsequently confirmed by histopathological examination of a skin biopsy. Cytological examination of a bone marrow aspirate revealed numerous histiocytes, which is suspect for bone‐marrow infiltration by LCH.LCH is a condition in which a clonal population of Langerhans’ cells accumulates in various tissues, causing tissue damage and/or dysfunction. The prognosis of this disease depends on the age of the patient, the extent of the disease and the presence of vital organ failure. In case of organ dysfunction, systemic chemotherapy is indicated.Although very rare, LCH can be a life‐threatening disease. Early diagnosis can improve chances of survival. We briefly discuss diagnostic procedures and treatment.
Basal cell carcinoma and trichoepithelioma: a possible matter of confusion
Authors: Arits Aimée H. M. M. , Parren Lizelotte J. M. T. , Van Marion Arienne M. W. , Sommer Anja , Frank Jorge , Kelleners‐Smeets Nicole W. J. 
Published: November 2008

AbstractDifficulty in differentiation between a solitary basal cell carcinoma, which is known as a malign skin lesion and a benign trichoepithelioma, is a frequent problem in all day dermatologic practice. Clinically as well as histopathologically there are a lot of resemblances between these skin tumors. By means of two real life cases, we give here an overview of the possible problems and appliances in distinguishing these two entities; at the end we do some recommendation about the policy.
Coincidence of cutaneous follicle center lymphoma and diffuse large B‐cell lymphoma
Authors: Van Tuyll van Serooskerken Anne‐Moon , Mosterd Klara , Veraart Joep C. , Vermeer Maarten H. , Frank Jorge , Van Marion Ariënne M. W. 
Published: November 2008

AbstractPrimary cutaneous follicle center lymphoma (PCFCL) is a neoplasm with differentiation of centrocytes and centroblasts presenting in the skin. At the time of initial manifestation, extracutaneous involvement is absent. PCFCL is considered as an indolent variant of primary cutaneous B‐cell lymphomas since dissemination to extracutaneous sites is rare and the prognosis is favorable. Here we describe a 30‐year‐old man who was diagnosed with a cutaneous FCL and did not show extracutaneous affection at the time of occurrence. Six months later, however, he developed a diffuse large B‐cell non‐Hodgkin lymphoma localized in several lymph nodes of the neck that most likely reflects the occurrence of a second primary tumor in the same patient.
Photoallergic contact dermatitis caused by ultraviolet filters in different sunscreens
Authors: Collaris Esther J. H. , Frank Jorge 
Published: November 2008

AbstractOver the last decade, a change in the public awareness regarding the possible danger of excessive sunlight exposure has resulted in an increased consumption of sunscreens. These products contain a broad spectrum of putative sensitizers that can cause contact dermatitis and, upon exposure to ultraviolet (UV) irradiation, photocontact dermatitis. Among these sensitizing compounds, UV filters are the most frequent cause of photoallergic reactions. Although rarely observed, we here describe the occurrence of a photoallergic contact dermatitis in a 55‐year‐old man after the use of two different sunscreens. Photopatch testing showed hypersensitivity reactions of the delayed type against three different chemical UV filters, 4‐tert‐butyl‐4‐ methoxy‐dibenzoylmethane (Parsol 1789), 2‐ethylhexyl‐p‐methoxycinnamate (Parsol MCX), and isoamyl‐p‐methoxycinnamate (Neoheliopan).