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1.
Proc Natl Acad Sci U S A ; 112(24): 7362-8, 2015 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-26082541

RESUMO

Achieving the policy and practice shifts needed to secure ecosystem services is hampered by the inherent complexities of ecosystem services and their management. Methods for the participatory production and exchange of knowledge offer an avenue to navigate this complexity together with the beneficiaries and managers of ecosystem services. We develop and apply a knowledge coproduction approach based on social-ecological systems research and assess its utility in generating shared knowledge and action for ecosystem services. The approach was piloted in South Africa across four case studies aimed at reducing the risk of disasters associated with floods, wildfires, storm waves, and droughts. Different configurations of stakeholders (knowledge brokers, assessment teams, implementers, and bridging agents) were involved in collaboratively designing each study, generating and exchanging knowledge, and planning for implementation. The approach proved useful in the development of shared knowledge on the sizable contribution of ecosystem services to disaster risk reduction. This knowledge was used by stakeholders to design and implement several actions to enhance ecosystem services, including new investments in ecosystem restoration, institutional changes in the private and public sector, and innovative partnerships of science, practice, and policy. By bringing together multiple disciplines, sectors, and stakeholders to jointly produce the knowledge needed to understand and manage a complex system, knowledge coproduction approaches offer an effective avenue for the improved integration of ecosystem services into decision making.


Assuntos
Conservação dos Recursos Naturais/métodos , Desastres , Ecossistema , Tomada de Decisões , Secas , Incêndios , Inundações , Bases de Conhecimento , Comportamento de Redução do Risco , África do Sul , Ondas de Maré
2.
Nat Commun ; 14(1): 2582, 2023 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-37142574

RESUMO

Eastern Boundary Upwelling Systems (EBUS) are highly productive ecosystems. However, being poorly sampled and represented in global models, their role as atmospheric CO2 sources and sinks remains elusive. In this work, we present a compilation of shipboard measurements over the past two decades from the Benguela Upwelling System (BUS) in the southeast Atlantic Ocean. Here, the warming effect of upwelled waters increases CO2 partial pressure (pCO2) and outgassing in the entire system, but is exceeded in the south through biologically-mediated CO2 uptake through biologically unused, so-called preformed nutrients supplied from the Southern Ocean. Vice versa, inefficient nutrient utilization leads to preformed nutrient formation, increasing pCO2 and counteracting human-induced CO2 invasion in the Southern Ocean. However, preformed nutrient utilization in the BUS compensates with ~22-75 Tg C year-1 for 20-68% of estimated natural CO2 outgassing in the Southern Ocean's Atlantic sector (~ 110 Tg C year-1), implying the need to better resolve global change impacts on the BUS to understand the ocean's role as future sink for anthropogenic CO2.

4.
Fluids Barriers CNS ; 19(1): 25, 2022 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-35313913

RESUMO

BACKGROUND: Integral membrane protein 2A (ITM2A) is a transmembrane protein expressed in a variety of tissues; little is known about its function, particularly in the brain. ITM2A was found to be highly enriched in human brain versus peripheral endothelial cells by transcriptomic and proteomic studies conducted within the European Collaboration on the Optimization of Macromolecular Pharmaceutical (COMPACT) Innovative Medicines Initiative (IMI) consortium. Here, we report the work that was undertaken to determine whether ITM2A could represent a potential target for delivering drugs to the brain. METHODS: A series of ITM2A constructs, cell lines and specific anti-human and mouse ITM2A antibodies were generated. Binding and internalization studies in Human Embryonic Kidney 293 (HEK293) cells overexpressing ITM2A and in brain microvascular endothelial cells from mouse and non-human primate (NHP) were performed with these tools. The best ITM2A antibody was evaluated in an in vitro human blood brain barrier (BBB) model and in an in vivo mouse pharmacokinetic study to investigate its ability to cross the BBB. RESULTS: Antibodies specifically recognizing extracellular parts of ITM2A or tags inserted in its extracellular domain showed selective binding and uptake in ITM2A-overexpressing cells. However, despite high RNA expression in mouse and human microvessels, the ITM2A protein was rapidly downregulated when endothelial cells were grown in culture, probably explaining why transcytosis could not be observed in vitro. An attempt to directly demonstrate in vivo transcytosis in mice was inconclusive, using either a cross-reactive anti-ITM2A antibody or in vivo phage panning of an anti-ITM2A phage library. CONCLUSIONS: The present work describes our efforts to explore the potential of ITM2A as a target mediating transcytosis through the BBB, and highlights the multiple challenges linked to the identification of new brain delivery targets. Our data provide evidence that antibodies against ITM2A are internalized in ITM2A-overexpressing HEK293 cells, and that ITM2A is expressed in brain microvessels, but further investigations will be needed to demonstrate that ITM2A is a potential target for brain delivery.


Assuntos
Células Endoteliais , Proteômica , Animais , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Células Endoteliais/metabolismo , Células HEK293 , Humanos , Proteínas de Membrana/metabolismo , Camundongos
5.
Harmful Algae ; 102: 101898, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33875181

RESUMO

The Benguela Upwelling System (BUS) is subject to a high incidence of HABs. Of the major shellfish poisoning syndromes associated with HABs, Paralytic and Diarrhetic Shellfish Poisoning (PSP and DSP) pose the greatest concern, but as documented herein there are several other HAB organisms that are also present. Blooms of Alexandrium catenella have been recognised as the typical cause of PSP since 1948. In addition to the risk posed to human health A. catenella has also been the cause of large shellfish and bird mortalities. An additional risk of PSP is provided by Alexandrium minutum first detected in Cape Town harbour in 2003. DSP was identified on the South African coast for the first time in 1991. Although several Dinophysis spp. known to cause DSP have been recognized as a component of the plankton of the region, it is accepted that DSP is usually attributed to D. acuminata or D. fortii. In the southern Benguela both Pseudo-nitzschia australis and Pseudo-nitzschia multiseries have been identified and shown to produce domoic acid. Multiple Pseudo-nitzschia spp. have been identified in the northern Benguela with the potentially toxigenic Pseudo-nitzschia pungens and P. australis dominant inshore. The yessotoxin (YTX) producing dinoflagellates Gonyaulax spinifera, Lingulodinium polyedrum and Protoceratium reticulatum are all known to form blooms and YTXs have been the cause of massive mortalities of farmed abalone. Prominent fish-killing blooms include Karlodinium veneficum in the northern Benguela and Karenia cristata in the southern Benguela. Shellfish farms in an embayment of the southern Benguela have suffered reduced growth rates due to the ecosystem disruptive blooms of Aureococcus anophagefferens. High biomass dinoflagellate blooms often attributed to Tripos and Prorocentrum spp. characterise the entire region and major mortalities of marine life are regularly attributed to their decay and the subsequent development of anoxic conditions.


Assuntos
Diatomáceas , Dinoflagellida , Animais , Ecossistema , Proliferação Nociva de Algas , África do Sul
6.
PLoS One ; 16(11): e0258124, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34818329

RESUMO

Due to their lithotrophic metabolisms, morphological complexity and conspicuous appearance, members of the Beggiatoaceae have been extensively studied for more than 100 years. These bacteria are known to be primarily sulfur-oxidizing autotrophs that commonly occur in dense mats at redox interfaces. Their large size and the presence of a mucous sheath allows these cells to serve as sites of attachment for communities of other microorganisms. But little is known about their individual niche preferences and attached microbiomes, particularly in marine environments, due to a paucity of cultivars and their prevalence in habitats that are difficult to access and study. Therefore, in this study, we compare Beggiatoaceae strain composition, community composition, and geochemical profiles collected from sulfidic sediments at four marine stations off the coast of Namibia. To elucidate community members that were directly attached and enriched in both filamentous Beggiatoaceae, namely Ca. Marithioploca spp. and Ca. Maribeggiatoa spp., as well as non-filamentous Beggiatoaceae, Ca. Thiomargarita spp., the Beggiatoaceae were pooled by morphotype for community analysis. The Beggiatoaceae samples collected from a highly sulfidic site were enriched in strains of sulfur-oxidizing Campylobacterota, that may promote a more hospitable setting for the Beggiatoaceae, which are known to have a lower tolerance for high sulfide to oxygen ratios. We found just a few host-specific associations with the motile filamentous morphotypes. Conversely, we detected 123 host specific enrichments with non-motile chain forming Beggiatoaceae. Potential metabolisms of the enriched strains include fermentation of host sheath material, syntrophic exchange of H2 and acetate, inorganic sulfur metabolism, and nitrite oxidation. Surprisingly, we did not detect any enrichments of anaerobic ammonium oxidizing bacteria as previously suggested and postulate that less well-studied anaerobic ammonium oxidation pathways may be occurring instead.


Assuntos
Bactérias/metabolismo , Sedimentos Geológicos/microbiologia , Microbiota , Enxofre/metabolismo , Geografia , Namíbia , Análise de Componente Principal , RNA Ribossômico 16S/genética
7.
Chemosphere ; 265: 129065, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33261834

RESUMO

New data on the presence of 129I in seawater in the Southern Hemisphere measured by Accelerator Mass Spectrometry (AMS) is presented. The samples were collected in 2014 along the Namibian coast during a cruise organised by the National Marine Information and Research Centre (NatMIRC), the national laboratories of the Ministry of Fisheries and Marine Resources (MFMR) in Namibia, and the IAEA Environment Laboratories (IAEA NAEL) in Monaco. The Benguela upwelling system is known as one of the most important marine upwelling regions in the world. Strong winds induce an offshore transport of surface seawater which is substituted by cool subsurface water inshore. As this water is nutrient-rich, which leads to high primary productivity, the Benguela upwelling system has a very important role as a fishing production area. The 129I concentrations in samples were between (0.66 ± 0.14) × 107 and (1.45 ± 0.30) × 107 atoms/kg. The highest 129I concentrations were found in the offshore surface samples. Deep-sea and inshore samples contained lower 129I concentrations, possibly as an effect of the upwelling process. A comparison with previously published studies suggests that the presence of 129I in the northern Benguela upwelling system (nBUS), is mainly due to the impact of nuclear weapons global fallout, without any evident impact of nuclear fuel reprocessing.


Assuntos
Água do Mar , Vento , Radioisótopos do Iodo , Namíbia
8.
Sci Total Environ ; 708: 135222, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31791767

RESUMO

The Benguela Upwelling System (BUS), off the south-western African coast, is one of the four major eastern boundary upwelling ecosystems in the oceans. However, this area has been overlooked in the field of environmental radioactivity. In this work, 236U and 237Np were collected off the coast of Namibia within the northern BUS. Surface seawater exhibited similar 236U and 237Np concentrations, ranging from 3.9·106 to 5.6·106 atoms kg-1 and from 4.6·106 to 8.5·106 atoms kg-1, respectively. The observed inventories in a water column from the continental margin, of (2.10 ± 0.11)·1012 atoms m-2 for 236U and (3.48 ± 0.13)·1012 atoms m-2 for 237Np, were in agreement with the global fallout (GF) source term in the Southern Hemisphere that was the main source of actinides to the region. A pattern was observed in the surface samples, with 237Np concentrations that decreased by 25-30% when moving from inshore to offshore stations, but such an effect could not be clearly discerned in the case of 236U within the data uncertainties. An explanation based on the larger particle reactivity of GF 237Np compared to GF 236U was proposed. Such an effect would have been important at the studied site due to the enhance presence of particles in the continental shelf triggered by the upwelling phenomenon. A value of 1.77 ± 0.20 was obtained for the 237Np/236U atom ratio for the GF source term in the marine environment.

9.
Geobiology ; 17(1): 76-90, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30369004

RESUMO

The processes that lead to the precipitation of authigenic calcium phosphate minerals in certain marine pore waters remain poorly understood. Phosphogenesis occurs in sediments beneath some oceanic upwelling zones that harbor polyphosphate-accumulating bacteria. These bacteria are believed to concentrate phosphate in sediment pore waters, creating supersaturated conditions with respect to apatite precursors. However, the relationship between microbes and phosphorite formation is not fully resolved. To further study this association, we examined microbial community data generated from two sources: sediment cores recovered from the shelf of the Benguela upwelling region where phosphorites are currently forming, and DNA preserved within phosphoclasts recovered from a phosphorite deposit along the Benguela shelf. iTag and clone library sequencing of the 16S rRNA gene showed that many of our sediment-hosted communities shared large numbers of phylotypes with one another, and that the same metabolic guilds were represented at localities across the shelf. Sulfate-reducing bacteria and sulfur-oxidizing bacteria were particularly abundant in our datasets, as were phylotypes that are known to carry out nitrification and the anaerobic oxidation of ammonium. The DNA extracted from phosphoclasts contained the signature of a distinct microbial community from those observed in the modern sediments. While some aspects of the modern and phosphoclast communities were similar, we observed both an enrichment of certain common microbial classes found in the modern phosphogenic sediments and a relative depletion of others. The phosphoclast-associated DNA could represent a relict signature of one or more microbial assemblages that were present when the apatite or its precursors precipitated. While these taxa may or may not have contributed to the precipitation of the apatite that now hosts their genetic remains, several groups represented in the phosphoclast extract dataset have the genetic potential to metabolize polyphosphate, and perhaps modulate phosphate concentrations in pore waters where carbonate fluorapatite (or its precursors) are known to be precipitating.


Assuntos
Organismos Aquáticos/metabolismo , Bactérias/metabolismo , DNA Bacteriano/análise , Sedimentos Geológicos/química , Minerais/análise , Fosfatos/análise , Oceano Atlântico
10.
Harmful Algae ; 75: 118-128, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29778221

RESUMO

The Benguela upwelling system, considered the world's most productive marine ecosystem, has a long record of potentially toxic diatoms belonging to the genus Pseudo-nitzschia. Species of Pseudo-nitzschia were reported as early as 1936 from the northern Benguela upwelling system (nBUS). For the current study, long-term phytoplankton monitoring data (2004-2011) for the Namibian coast were analysed to examine inshore and offshore temporal distribution of Pseudo-nitzschia species, their diversity and ultrastructure. The potentially toxigenic P. pungens and P. australis were the dominant inshore species, whereas offshore Pseudo-nitzschia showed a higher diversity that also included potentially toxic species. During a warming event, a community shift from P. pungens and P. australis dominance to P. fraudulenta and P. multiseries was documented in the central nBUS. A case study of a toxic event (August 2004) revealed that P. australis and P. pungens were present at multiple inshore and offshore stations, coincident with fish (pilchard) and bird mortalities reported from the central part of Namibia. Toxin analyses (LC-MS/MS) of samples collected from June to August 2004 revealed the presence of particulate domoic acid (DA) in seawater at multiple stations (maximum ∼180 ng DA/L) in the >0.45 µm size-fraction, as well as detectable DA (0.12 µg DA/g) in the gut of one of two pilchard samples tested. These findings indicate that DA may have been associated with the fish and bird mortalities reported from this event in the nBUS. However, the co-occurrence of very high biomass phytoplankton blooms suggests that other explanations may be possible.


Assuntos
Diatomáceas/química , Ácido Caínico/análogos & derivados , Toxinas Marinhas/análise , Oceano Atlântico , Biodiversidade , Cromatografia Líquida , Diatomáceas/classificação , Diatomáceas/ultraestrutura , Ácido Caínico/análise , Microscopia Eletrônica de Transmissão , Namíbia , Fitoplâncton/química , Fitoplâncton/classificação , Fitoplâncton/ultraestrutura , Espectrometria de Massas em Tandem
11.
Harmful Algae ; 76: 80-95, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29887207

RESUMO

A field study was undertaken to investigate the occurrence and toxin production of species in the diatom genus Pseudo-nitzschia in Namibian waters, in the extremely productive Benguela upwelling system. From surveys conducted on the R/V Mirabilis and the R/V !Anichab, 52 strains were morphologically determined to species level, supported by nuclear ITS rDNA data. Seven species were identified; P. australis, P. decipiens, P. dolorosa, P. fraudulenta, P. plurisecta, P. pungens var. cingulata, and the new species P. bucculenta F. Gai, C. K. Hedemand, N. Lundholm & Ø. Moestrup sp. nov. Molecular and morphological diversity of the Namibian Pseudo-nitzschia species is discussed. Most importantly, P. bucculenta is both morphologically and phylogenetically most similar to P. dolorosa differing mainly in valve width and densities of striae, poroids and band striae as well as by four hemi-compensatory base changes in the ITS2. Morphological and molecular differences among the strains of P. decipiens suggest a temperate and a warm water subdivision. The geographical and toxigenic characteristics of the identified Pseudo-nitzschia species are described and compared to previous studies. Initial tests of toxin production in all seven species revealed production of domoic acid (DA) in two species: one strain of P. australis (0.074 pg DA cell-1) and two strains of P. plurisecta (0.338 pg DA cell-1 and 0.385 pg DA cell-1).


Assuntos
Diatomáceas/classificação , DNA de Algas/análise , DNA Espaçador Ribossômico/análise , Diatomáceas/química , Diatomáceas/genética , Diatomáceas/ultraestrutura , Toxinas Marinhas , Microscopia Eletrônica de Transmissão , Namíbia
12.
J Am Soc Mass Spectrom ; 7(2): 163-7, 1996 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24203237

RESUMO

Hemoglobin Villeparisis was found during a systematic measurement of glycated hemoglobin. Electrospray mass spectra of the globin indicate an apparently unchanged molecular weight within the error range (0.01%). The tryptic digest of the ß chain shows a chromatographically abnormal ßT-9 peptide. The mass-to-charge ratio value of its [M+H](+) ion, as measured by liquid secondary ionization mass spectrometry, is one mass unit lower than that of the normal ßT-9. However, the electrospray mass spectrum of this peptide exhibits mainly a doubly charged ion, whereas the normal ßT-9 gives a triply charged ion. None of the allowed single amino acid substitutions for a 1-u shift down (Glu → Gln, Asp → Asn, or Asn → Ile) can explain the suppression of one protonation site. This can be due only to the replacement of the internal histidine by a nonbasic residue. Thus at least two amino acid exchanges occur within the same peptide: one involves the internal histidine, and the sum of the mass shifts is -1 u. Consideration of the ßT-9 sequence and taking account for the genetic code rules, the only possibility was (11)His → Tyr (+26 mass shift) associated with (14)Asn → Ser (-27 mass shift). This conclusion was consistent with the tandem mass spectrum of the [M+H](+) ion and was further confirmed by chemical microsequencing.

13.
J Mass Spectrom ; 32(8): 880-7, 1997 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9269086

RESUMO

Mutation-induced amino acid exchanges occurring on the large T9 peptide of the alpha-chain of human hemoglobin (residues 62-90) are difficult to identify. Despite their high m/z value (around m/z 3000), collision-induced dissociation spectra of liquid secondary ion mass spectrometrically generated protonated alpha T9 peptides were performed successfully. In parallel electrospray mass spectrometry (MS) was used both to measure the molecular mass of the intact proteins and to determine the number of protonatable sites in the alpha T9 peptides. Peptide ladder sequencing using carboxypeptidase digestions and analysis of the truncated peptides by matrix-assisted laser desorption ionization time-of-flight MS confirmed the interpretation. This set of methods allowed the characterization of three hemoglobin variants, with amino acid exchanges located in the alpha T9 part of the sequence. Two of them, Hb Aztec [alpha 76(EF5) Met-->Thr] and Hb M-Iwate [alpha 87(F8) His-->Tyr] were already known. The third [alpha 89(FG1) His-->Tyr] was novel and named Hb Villeurbanne.


Assuntos
Hemoglobinas Anormais/química , Espectrometria de Massas/métodos , Sequência de Aminoácidos , Carboxipeptidases/metabolismo , Cromatografia Líquida de Alta Pressão , Eletroforese em Acetato de Celulose , Globinas/química , Globinas/genética , Hemoglobina M/química , Hemoglobina M/genética , Hemoglobinas Anormais/genética , Humanos , Dados de Sequência Molecular , Peso Molecular , Mutação , Peptídeos/química , Análise de Sequência , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Tripsina/metabolismo
14.
PLoS One ; 9(5): e97738, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24844305

RESUMO

Long-term data sets are essential to understand climate-induced variability in marine ecosystems. This study provides the first comprehensive analysis of longer-term temporal and spatial variations in zooplankton abundance and copepod community structure in the northern Benguela upwelling system from 2005 to 2011. Samples were collected from the upper 200 m along a transect at 20 °S perpendicular to the coast of Namibia to 70 nm offshore. Based on seasonal and interannual trends in surface temperature and salinity, three distinct time periods were discernible with stronger upwelling in spring and extensive warm-water intrusions in late summer, thus, high temperature amplitudes, in the years 2005/06 and 2010/11, and less intensive upwelling followed by weaker warm-water intrusions from 2008/09 to 2009/10. Zooplankton abundance reflected these changes with higher numbers in 2005/06 and 2010/11. In contrast, zooplankton density was lower in 2008/09 and 2009/10, when temperature gradients from spring to late summer were less pronounced. Spatially, copepod abundance tended to be highest between 30 and 60 nautical miles off the coast, coinciding with the shelf break and continental slope. The dominant larger calanoid copepods were Calanoides carinatus, Metridia lucens and Nannocalanus minor. On all three scales studied, i.e. spatially from the coast to offshore waters as well as temporally, both seasonally and interannually, maximum zooplankton abundance was not coupled to the coldest temperature regime, and hence strongest upwelling intensity. Pronounced temperature amplitudes, and therefore strong gradients within a year, were apparently important and resulted in higher zooplankton abundance.


Assuntos
Copépodes , Ecossistema , Análise Espaço-Temporal , Animais , Biodiversidade , Clima , Namíbia , Densidade Demográfica , Dinâmica Populacional , Estações do Ano , Água do Mar
15.
PLoS One ; 9(5): e95942, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24806527

RESUMO

Communities worldwide are increasingly affected by natural hazards such as floods, droughts, wildfires and storm-waves. However, the causes of these increases remain underexplored, often attributed to climate changes or changes in the patterns of human exposure. This paper aims to quantify the effect of climate change, as well as land cover change, on a suite of natural hazards. Changes to four natural hazards (floods, droughts, wildfires and storm-waves) were investigated through scenario-based models using land cover and climate change drivers as inputs. Findings showed that human-induced land cover changes are likely to increase natural hazards, in some cases quite substantially. Of the drivers explored, the uncontrolled spread of invasive alien trees was estimated to halve the monthly flows experienced during extremely dry periods, and also to double fire intensities. Changes to plantation forestry management shifted the 1:100 year flood event to a 1:80 year return period in the most extreme scenario. Severe 1:100 year storm-waves were estimated to occur on an annual basis with only modest human-induced coastal hardening, predominantly from removal of coastal foredunes and infrastructure development. This study suggests that through appropriate land use management (e.g. clearing invasive alien trees, re-vegetating clear-felled forests, and restoring coastal foredunes), it would be possible to reduce the impacts of natural hazards to a large degree. It also highlights the value of intact and well-managed landscapes and their role in reducing the probabilities and impacts of extreme climate events.


Assuntos
Conservação dos Recursos Naturais/métodos , Desastres/prevenção & controle , Ecossistema , Mudança Climática , Secas , Monitoramento Ambiental , Incêndios , Inundações , Humanos
17.
Proteomics ; 1(10): 1288-94, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11721640

RESUMO

Renal cell carcinoma (RCC) originates in the renal cortex. It accounts for 2-3 percent of all cancers occurring in adults and it is characterised by lack of early clinical manifestations, unpredictable outcome, and absence of effective treatment modalities except early surgery. RCC comprises a heterogeneous group of tumours with various molecular and cytogenetic abnormalities and different histological features as cell types and tumour architecture. Molecular genetic and proteomic tools led to the discovery of potential diagnostic prognostic and therapeutic biomarkers of RCC. In this review we discuss recent developments in understanding genotype-phenotype relationships, with attention to manganese superoxide dismutase, a mitochondrial enzyme related to the redox cycle which affects various regulatory functions of cells. The expression of this protein has been evaluated in numerous human tumour types including RCC, and post-translational modifications are being investigated.


Assuntos
Carcinoma de Células Renais/enzimologia , Carcinoma de Células Renais/fisiopatologia , Proteoma/metabolismo , Superóxido Dismutase/metabolismo , Biomarcadores Tumorais/metabolismo , Carcinoma de Células Renais/diagnóstico , Carcinoma de Células Renais/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Prognóstico , Processamento de Proteína Pós-Traducional , Superóxido Dismutase/química , Superóxido Dismutase/genética
18.
Anal Chem ; 73(18): 4537-44, 2001 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-11575804

RESUMO

Mycolic acids, major and specific long-chain fatty (C70-C90) acid components of the mycobacterial cell envelope, were analyzed for the first time using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry operating in a reflectron mode. The various types of purified mycolates from representative mycobacterial species were analyzed using 2,5-DHB as matrix, because less than 10 pmol of mycolates was sufficient to obtain well-resolved mass spectra composed exclusively of pseudomolecular [M + Na]+ ions consistent with the structures deduced from the chemical analytical techniques applied to these molecules. Examination of the MALDI mass spectra demonstrated that the chain lengths of the various mycolates correlated with the growth rate of mycobacterial strains. Although slow growers, such as Mycobacterium tuberculosis and Mycobacterium ulcerans, produced a series of odd carbon numbers (C74-C82) of alpha-mycolic acids, rapid growers synthesized both odd and even carbon numbers. In addition, the main chain of oxygenated mycolic acids from slow growers were four to six carbon atoms longer than the corresponding alpha-mycolic acids, whereas rapid growers elaborated oxygenated homologues possessing the same chain lengths as their alpha-mycolic acids. Furthermore, a comparative analysis of the crude fatty acid mixtures from a wild-type strain of M. tuberculosis and its isogenic mutant effected in the synthesis of oxygenated mycolates by MALDI mass spectrometry revealed structural differences between the alpha-mycolates from the two strains. Thus, this technique appeared to be a rapid and highly sensitive technique for the analysis of mycolic acids, not only by providing accurate molecular masses and new structural information, but also by both reducing sample consumption and saving time.


Assuntos
Ácidos Micólicos/análise , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Estrutura Molecular , Mycobacterium smegmatis/química , Mycobacterium tuberculosis/química , Mycobacterium ulcerans/química
19.
Rapid Commun Mass Spectrom ; Spec No: S165-8, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-8829478

RESUMO

A new electrophoreticaly neutral hemoglobin variant was found by ion-exchange high-performance liquid chromatography (HPLC). The molecular mass of the beta-chain was shifted down 28 mass units. The modification was found in the beta T-11 peptide that co-elutes with beta T-14 in the tryptic HPLC profile. Collision-induced decomposition of the protonated modified peptide indicated the Arg --> Lys exchange at the C-terminus. This modifies the fragmentation pattern as charge-remote processes induced by the strong basicity of arginine were replaced by charge-induced mechanisms. The exchanged 104Arg is one of the chloride binding sites in the central cavity of Hb.


Assuntos
Cromatografia Líquida de Alta Pressão , Hemoglobinas Anormais/química , Sequência de Aminoácidos , Globinas/química , Globinas/isolamento & purificação , Hemoglobinas Anormais/isolamento & purificação , Humanos , Dados de Sequência Molecular , Peso Molecular , Peptídeos/química , Peptídeos/isolamento & purificação , Tripsina
20.
Hemoglobin ; 22(2): 129-40, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9576330

RESUMO

Hb Les Andelys [alpha83(F4)Leu-->Pro] is a mildly unstable variant that was found during glycated hemoglobin measurement in a French family. In this hemoglobin molecule the affected site, in the alpha chain, and the amino acid substitution are identical to those of Hb Santa Ana, an unstable beta chain variant. The structural abnormality was demonstrated by protein chemistry methods, involving, in addition to the classical techniques, a selective precipitation of the abnormal hemoglobin by isopropanol and a mass spectrometry analysis of the alphaT-9 peptide following carboxypeptidase digestion. DNA sequencing demonstrated that the mutation was CTG-->CCG at codon 83 of the alpha2 gene.


Assuntos
Globinas/genética , Hemoglobinas Anormais/isolamento & purificação , Mutação Puntual , Sequência de Aminoácidos , Eletroforese das Proteínas Sanguíneas , Criança , Cromatografia Líquida de Alta Pressão , Cromatografia por Troca Iônica , Códon/genética , Análise Mutacional de DNA , Diabetes Mellitus Tipo 1/sangue , Feminino , Hemoglobinas Glicadas/análise , Hemoglobinas Anormais/química , Hemoglobinas Anormais/genética , Humanos , Focalização Isoelétrica , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Desnaturação Proteica , Análise de Sequência de DNA
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