24 resultados para Hansen, Lars
Resumo:
Background: Annotations of completely sequenced genomes reveal that nearly half of the genes identified are of unknown function, and that some belong to uncharacterized gene families. To help resolve such issues, information can be obtained from the comparative analysis of homologous genes in model organisms. Results: While characterizing genes from the retinitis pigmentosa locus RP26 at 2q31-q33, we have identified a new gene, ORMDL1, that belongs to a novel gene family comprising three genes in humans (ORMDL1, ORMDL2 and ORMDL3), and homologs in yeast, microsporidia, plants, Drosophila, urochordates and vertebrates. The human genes are expressed ubiquitously in adult and fetal tissues. The Drosophila ORMDL homolog is also expressed throughout embryonic and larval stages, particularly in ectodermally derived tissues. The ORMDL genes encode transmembrane proteins anchored in the endoplasmic reticulum (ER). Double knockout of the two Saccharomyces cerevisiae homologs leads to decreased growth rate and greater sensitivity to tunicamycin and dithiothreitol. Yeast mutants can be rescued by human ORMDL homologs. Conclusions: From protein sequence comparisons we have defined a novel gene family, not previously recognized because of the absence of a characterized functional signature. The sequence conservation of this family from yeast to vertebrates, the maintenance of duplicate copies in different lineages, the ubiquitous pattern of expression in human and Drosophila, the partial functional redundancy of the yeast homologs and phenotypic rescue by the human homologs, strongly support functional conservation. Subcellular localization and the response of yeast mutants to specific agents point to the involvement of ORMDL in protein folding in the ER.
Resumo:
Portulaca granulato-stellulata (Poellnitz) C. Ricceri & P. V. Arrigoni is a subcosmopolitan plant of uncertain origin (DANIN et al., 1978; DANIN, 2000). It has been recently reported from Tenerife Island (DANIN & REYES-BETANCORT, 2006), the first reference for the Canary Islands, since prior to this, the taxon had not been detected from any of the Macaronesian islands. Its presence was undetected due to its inclusion within the complex Portulaca oleracea sensu lato (HANSEN & SUNDING, 1993: 170; STIERSTORFER & GAISBERG, 2006).
Resumo:
Membrane-aerated biofilm reactors performing autotrophic nitrogen removal can be successfully applied to treat concentrated nitrogen streams. However, their process performance is seriously hampered by the growth of nitrite oxidizing bacteria (NOB). In this work we document how sequential aeration can bring the rapid and long-term suppression of NOB and the onset of the activity of anaerobic ammonium oxidizing bacteria (AnAOB). Real-time quantitative polymerase chain reaction analyses confirmed that such shift in performance was mirrored by a change in population densities, with a very drastic reduction of the NOB Nitrospira and Nitrobacter and a 10-fold increase in AnAOB numbers. The study of biofilm sections with relevant 16S rRNA fluorescent probes revealed strongly stratified biofilm structures fostering aerobic ammonium oxidizing bacteria (AOB) in biofilm areas close to the membrane surface (rich in oxygen) and AnAOB in regions neighbouring the liquid phase. Both communities were separated by a transition region potentially populated by denitrifying heterotrophic bacteria. AOB and AnAOB bacterial groups were more abundant and diverse than NOB, and dominated by the r-strategists Nitrosomonas europaea and Ca. Brocadia anammoxidans, respectively. Taken together, the present work presents tools to better engineer, monitor and control the microbial communities that support robust, sustainable and efficient nitrogen removal
Resumo:
Leprosy is a contagious and chronic systemic granulomatous disease caused by Mycobacterium leprae (Hansen"s bacillus). It is transmitted from person to person and has a long incubation period (between two and six years). The disease presents polar clinical forms (the"multibacillary" lepromatous leprosy and the"paucibacillary" tuberculoid leprosy), as well as other intermediate forms with hybrid characteristics. Oral manifestations usually appear in lepromatous leprosy and occur in 20-60% of cases. They may take the form of multiple nodules (lepromas) that progress to necrosis and ulceration. The ulcers are slow to heal, and produce atrophic scarring or even tissue destruction. The lesions are usually located on the hard and soft palate, in the uvula, on the underside of the tongue, and on the lips and gums. There may also be destruction of the anterior maxilla and loss of teeth. The diagnosis, based on clinical suspicion, is confirmed through bacteriological and histopathological analyses, as well as by means of the lepromin test (intradermal reaction that is usually negative in lepromatous leprosy form and positive in the tuberculoid form). The differential diagnosis includes systemic lupus erythematosus, sarcoidosis, cutaneous leishmaniasis and other skin diseases, tertiary syphilis, lymphomas, systemic mycosis, traumatic lesions and malignant neoplasias, among other disorders. Treatment is difficult as it must be continued for long periods, requires several drugs with adverse effects and proves very expensive, particularly for less developed countries. The most commonly used drugs are dapsone, rifampicin and clofazimine. Quinolones, such as ofloxacin and pefloxacin, as well as some macrolides, such as clarithromycin and minocyclin, are also effective. The present case report describes a patient with lepromatous leprosy acquired within a contagious family setting during childhood and adolescence
Resumo:
With the increasing availability of various 'omics data, high-quality orthology assignment is crucial for evolutionary and functional genomics studies. We here present the fourth version of the eggNOG database (available at http://eggnog.embl.de) that derives nonsupervised orthologous groups (NOGs) from complete genomes, and then applies a comprehensive characterization and analysis pipeline to the resulting gene families. Compared with the previous version, we have more than tripled the underlying species set to cover 3686 organisms, keeping track with genome project completions while prioritizing the inclusion of high-quality genomes to minimize error propagation from incomplete proteome sets. Major technological advances include (i) a robust and scalable procedure for the identification and inclusion of high-quality genomes, (ii) provision of orthologous groups for 107 different taxonomic levels compared with 41 in eggNOGv3, (iii) identification and annotation of particularly closely related orthologous groups, facilitating analysis of related gene families, (iv) improvements of the clustering and functional annotation approach, (v) adoption of a revised tree building procedure based on the multiple alignments generated during the process and (vi) implementation of quality control procedures throughout the entire pipeline. As in previous versions, eggNOGv4 provides multiple sequence alignments and maximum-likelihood trees, as well as broad functional annotation. Users can access the complete database of orthologous groups via a web interface, as well as through bulk download.
Resumo:
Background: Annotations of completely sequenced genomes reveal that nearly half of the genes identified are of unknown function, and that some belong to uncharacterized gene families. To help resolve such issues, information can be obtained from the comparative analysis of homologous genes in model organisms. Results: While characterizing genes from the retinitis pigmentosa locus RP26 at 2q31-q33, we have identified a new gene, ORMDL1, that belongs to a novel gene family comprising three genes in humans (ORMDL1, ORMDL2 and ORMDL3), and homologs in yeast, microsporidia, plants, Drosophila, urochordates and vertebrates. The human genes are expressed ubiquitously in adult and fetal tissues. The Drosophila ORMDL homolog is also expressed throughout embryonic and larval stages, particularly in ectodermally derived tissues. The ORMDL genes encode transmembrane proteins anchored in the endoplasmic reticulum (ER). Double knockout of the two Saccharomyces cerevisiae homologs leads to decreased growth rate and greater sensitivity to tunicamycin and dithiothreitol. Yeast mutants can be rescued by human ORMDL homologs. Conclusions: From protein sequence comparisons we have defined a novel gene family, not previously recognized because of the absence of a characterized functional signature. The sequence conservation of this family from yeast to vertebrates, the maintenance of duplicate copies in different lineages, the ubiquitous pattern of expression in human and Drosophila, the partial functional redundancy of the yeast homologs and phenotypic rescue by the human homologs, strongly support functional conservation. Subcellular localization and the response of yeast mutants to specific agents point to the involvement of ORMDL in protein folding in the ER.
Resumo:
Mercurialis canariensis Obbard & S. A. Harris is an endemic plant recently described from the Canary Islands (OBBARD et al., 2006b: 103). This taxon went undetected until recently, having been included within the variability of the Mercurialis annua sensu lato complex (HANSEN & SUNDING, 1993:170; STIERSTORFER & GAISBERG, 2006).
Resumo:
Leprosy is a contagious and chronic systemic granulomatous disease caused by Mycobacterium leprae (Hansen"s bacillus). It is transmitted from person to person and has a long incubation period (between two and six years). The disease presents polar clinical forms (the"multibacillary" lepromatous leprosy and the"paucibacillary" tuberculoid leprosy), as well as other intermediate forms with hybrid characteristics. Oral manifestations usually appear in lepromatous leprosy and occur in 20-60% of cases. They may take the form of multiple nodules (lepromas) that progress to necrosis and ulceration. The ulcers are slow to heal, and produce atrophic scarring or even tissue destruction. The lesions are usually located on the hard and soft palate, in the uvula, on the underside of the tongue, and on the lips and gums. There may also be destruction of the anterior maxilla and loss of teeth. The diagnosis, based on clinical suspicion, is confirmed through bacteriological and histopathological analyses, as well as by means of the lepromin test (intradermal reaction that is usually negative in lepromatous leprosy form and positive in the tuberculoid form). The differential diagnosis includes systemic lupus erythematosus, sarcoidosis, cutaneous leishmaniasis and other skin diseases, tertiary syphilis, lymphomas, systemic mycosis, traumatic lesions and malignant neoplasias, among other disorders. Treatment is difficult as it must be continued for long periods, requires several drugs with adverse effects and proves very expensive, particularly for less developed countries. The most commonly used drugs are dapsone, rifampicin and clofazimine. Quinolones, such as ofloxacin and pefloxacin, as well as some macrolides, such as clarithromycin and minocyclin, are also effective. The present case report describes a patient with lepromatous leprosy acquired within a contagious family setting during childhood and adolescence
Resumo:
Fungi and bacteria are key agents in plant litter decomposition in freshwater ecosystems. However, the specific roles of these two groups and their interactions during the decomposition process are unclear. We compared the growth and patterns of degradativeenzymes expressed by communities of bacteria and fungi grown separately and in coexistence on Phragmites leaves. The two groups displayed both synergistic and antagonistic interactions. Bacteria grew better together with fungi than alone. In addition, there was a negative effect of bacteria on fungi, which appeared to be caused by suppression of fungal growth and biomass accrual rather than specifically affecting enzyme activity. Fungi growing alone had a high capacity for the decomposition of plant polymers such as lignin, cellulose, and hemicellulose. In contrast, enzyme activities were in general low when bacteria grew alone, and the activity of key enzymes in the degradation of lignin and cellulose (phenol oxidase and cellobiohydrolase) was undetectable in the bacteria-only treatment. Still, biomass-specific activities of most enzymes were higher in bacteria than in fungi. The low total activity and growth of bacteria in the absence of fungi in spite of apparent high enzymatic efficiency during the degradation of many substrates suggest that fungi provide the bacteria with resources that the bacteria were not able to acquire on their own, most probably intermediate decomposition products released by fungi that could be used by bacteria