RESUMO
This article focuses on the indifference and annoyance that preceded and followed the UN Food Systems Summit and its preparatory meetings. It argues that, from a European perspective, the Food Systems Summit agenda does not entail anything new, whilst its impact will negatively fire back by further increasing dependencies and fragilities in the food system.
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The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses. As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world's major tropical regions. Our analysis reveals great variation in reserve 'health': about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.
Assuntos
Biodiversidade , Conservação dos Recursos Naturais/estatística & dados numéricos , Espécies em Perigo de Extinção/estatística & dados numéricos , Árvores/fisiologia , Clima Tropical , Agricultura/estatística & dados numéricos , Animais , Coleta de Dados , Ecologia/estatística & dados numéricos , Poluição Ambiental/efeitos adversos , Poluição Ambiental/estatística & dados numéricos , Incêndios/estatística & dados numéricos , Agricultura Florestal/estatística & dados numéricos , Entrevistas como Assunto , Mineração/estatística & dados numéricos , Crescimento Demográfico , Chuva , Reprodutibilidade dos Testes , Pesquisadores , Inquéritos e Questionários , TemperaturaRESUMO
Livelihood diversification has become an integral focus of policies and investments aiming to reduce poverty, vulnerability, and pressure on fishery resources in coastal communities around the globe. In this regard, coastal fisheries in the Pacific Islands have long been a sector where livelihood diversification has featured prominently. Yet, despite the widespread promotion and international investment in this strategy, the ability of externally funded livelihood diversification projects to facilitate improved resource management and rural development outcomes often remains inconsistent. We argue these inconsistencies can be attributed to a conceptual ambiguity stemming from a lack of attention and awareness to the complexity of livelihood diversification. There is still much to learn about the process of livelihood diversification, both in its theoretical conceptualizations and its practical applications. Herein, we utilize a common diversity framework to clarify some of this ambiguity by distinguishing three diversification pathways. These pathways are illustrated using an ideal-typical Pacific Island coastal household and supported by examples provided in the literature that detail livelihood diversification projects in the Pacific. Through this perspective, we seek a more nuanced understanding of what is meant within the policy and practice goal of livelihood diversification. Thereby enabling more targeted and deliberate planning for development investments that facilitates outcomes in support of sustainable livelihoods.
Assuntos
Conservação dos Recursos Naturais , Pesqueiros , Características da Família , Ilhas do Pacífico , PobrezaRESUMO
Coastal fisheries are a critical component of Pacific island food systems; they power village economies and provide nutritious aquatic foods. Many coastal women and men actively fishing in this region rely on multi-species fisheries, which given their extraordinary diversity are notoriously difficult to both characterize, and to manage. Understanding patterns of fishing, diversity of target species and drivers of these patterns can help define requirements for sustainable management and enhanced livelihoods. Here we use a 12-month data set of 8535 fishing trips undertaken by fishers across Malaita province, Solomon Islands, to create fisheries signatures for 13 communities based on the combination of two metrics; catch per unit effort (CPUE) and catch trophic levels. These signatures are in turn used as a framework for guiding suitable management recommendations in the context of community-based resource management. While a key proximate driver of these patterns was fishing gear (e.g. angling, nets or spearguns), market surveys and qualitative environmental information suggest that community fishing characteristics are coupled to local environmental features more than the market value of specific species they target. Our results demonstrate that even within a single island not all small-scale fisheries are equal, and effective management solutions ultimately depend on catering to the specific environmental characteristics around individual communities.
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Conservação dos Recursos Naturais , Pesqueiros , Animais , Conservação dos Recursos Naturais/métodos , Feminino , Peixes , Humanos , MelanesiaRESUMO
Bacteria can detect, transmit, and react to signals from the outside world by using two-component systems (TCS) and serine-threonine kinases and phosphatases. Streptococcus mutans contains one serine-threonine kinase, encoded by pknB. A gene encoding a serine-threonine phosphatase, pppL, is located upstream of pknB. In this study, the phenotypes of pknB and pppL single mutants and a pknB pppL double mutant were characterized. All mutants exhibited a reduction in genetic transformability and biofilm formation, showed abnormal cell shapes, grew slower than the wild-type strain in several complex media, and exhibited reduced acid tolerance. The mutants had reduced cariogenic capacity but no significant defects in colonization in a rat caries model. Whole-genome transcriptome analysis revealed that a pknB mutant showed reduced expression of genes involved in bacteriocin production and genetic competence. Among the genes that were differentially regulated in the pknB mutant, several were likely to be involved in cell wall metabolism. One such gene, SMU.2146c, and two genes encoding bacteriocins were shown to also be downregulated in a vicK mutant, which encodes a sensor kinase involved in the response to oxidative stress. Collectively, the results lead us to speculate that PknB may modulate the activity of the two-component signal transduction systems VicKR and ComDE. Real-time reverse transcriptase PCR (RT-PCR) showed that genes downregulated in the pknB mutant were upregulated in the pppL mutant, indicating that PppL serves to counteract PknB.
Assuntos
Proteínas de Bactérias/fisiologia , Bacteriocinas/biossíntese , Parede Celular/metabolismo , Regulação Bacteriana da Expressão Gênica , Proteínas Serina-Treonina Quinases/fisiologia , Streptococcus mutans/enzimologia , Streptococcus mutans/fisiologia , Transformação Bacteriana , Animais , Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Cárie Dentária/microbiologia , Modelos Animais de Doenças , Deleção de Genes , Perfilação da Expressão Gênica , Dados de Sequência Molecular , Fosfoproteínas Fosfatases/genética , Fosfoproteínas Fosfatases/fisiologia , Proteínas Serina-Treonina Quinases/genética , Ratos , Streptococcus mutans/genética , Streptococcus mutans/patogenicidadeRESUMO
Exponential growing cultures of Streptococcus oralis strain OMZ 1038, isolated from human supragingival dental plaque, were found to release a bacteriophage (designated PH10) upon treatment with mitomycin C. The complete genome sequence of phage PH10 was determined. The genome was 31276 bp in size and contained 54 open reading frames. The module encoding structural proteins was highly similar to that of Streptococcus pneumoniae prophage PhiSpn_3. The most abundant phage structural protein was encoded by ORF35 and was likely processed by proteolytic cleavage. The putative endolysin from PH10, which contained a muramidase domain and a choline-binding domain, was purified and shown to have lytic activity with S. oralis, S. pneumoniae and Streptococcus mitis, but not with other streptococcal species.
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Genoma Viral , Fagos de Streptococcus/genética , Streptococcus oralis/virologia , Placa Dentária/microbiologia , Humanos , Dados de Sequência Molecular , Fases de Leitura Aberta , Infecções Estreptocócicas/microbiologia , Fagos de Streptococcus/isolamento & purificação , Fagos de Streptococcus/fisiologia , Streptococcus oralis/isolamento & purificação , Proteínas Virais/genética , Proteínas Virais/metabolismoRESUMO
This paper examines some of the interrelations that exist between rural China's peasant economy and the wider economy in which it is embedded. In doing so it focuses on the circular flows that link town and countryside. Multiple job holding is strategic in this respect. The paper draws on research undertaken in a peasant village in Hebei Province. The research highlights some remarkable differences that exist between development processes in China and in other developing countries and traces these back to a combination of an enlightened rural policy and the strong linkages that exist between rural China and its urban "global factory".
Assuntos
Economia , Emprego , Saúde da População Rural , População Rural , Mudança Social , Condições Sociais , China/etnologia , Redes Comunitárias/economia , Redes Comunitárias/história , Redes Comunitárias/legislação & jurisprudência , Características Culturais , Economia/história , Economia/legislação & jurisprudência , Emprego/economia , Emprego/história , Emprego/legislação & jurisprudência , Emprego/psicologia , História do Século XX , História do Século XXI , Sistemas Políticos/história , Saúde da População Rural/história , População Rural/história , Mudança Social/história , Classe Social/história , Condições Sociais/economia , Condições Sociais/história , Condições Sociais/legislação & jurisprudênciaRESUMO
Large-bodied predators are well represented among the world's threatened and endangered species. A significant body of literature shows that in terrestrial and marine ecosystems large predators can play important roles in ecosystem structure and functioning. By contrast, the ecological roles and importance of large predators within freshwater ecosystems are poorly understood, constraining the design and implementation of optimal conservation strategies for freshwater ecosystems. Conservationists and environmentalists frequently promulgate ecological roles that crocodylians are assumed to fulfil, but often with limited evidence supporting those claims. Here, we review the available information on the ecological importance of crocodylians, a widely distributed group of predominantly freshwater-dwelling, large-bodied predators. We synthesise information regarding the role of crocodylians under five criteria within the context of modern ecological concepts: as indicators of ecological health, as ecosystem engineers, apex predators, keystone species, and as contributors to nutrient and energy translocation across ecosystems. Some crocodylians play a role as indicators of ecosystem health, but this is largely untested across the order Crocodylia. By contrast, the role of crocodylian activities in ecosystem engineering is largely anecdotal, and information supporting their assumed role as apex predators is currently limited to only a few species. Whether crocodylians contribute significantly to nutrient and energy translocation through cross-ecosystem movements is unknown. We conclude that most claims regarding the importance of crocodylians as apex predators, keystone species, ecosystem engineers, and as contributors to nutrient and energy translocation across ecosystems are mostly unsubstantiated speculation, drawn from anecdotal observations made during research carried out primarily for other purposes. There is a paucity of biological research targeted directly at: understanding population dynamics; trophic interactions within their ecological communities; and quantifying the short- and long-term ecological impacts of crocodylian population declines, extirpations, and recoveries. Conservation practices ideally need evidence-based planning, decision making and justification. Addressing the knowledge gaps identified here will be important for achieving effective conservation of crocodylians.
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Jacarés e Crocodilos/fisiologia , Conservação dos Recursos Naturais , Ecossistema , Animais , Espécies em Perigo de Extinção , Água Doce , Pesquisa/tendênciasRESUMO
The dramatic decline in the presence of farmland birds during recent decades has provoked much attention in agri-environmental policy and ecological research. However, the still limited understanding of the socio-economical mechanisms that govern the decline in bird presence hampers the formulation of effective adjustments in land-use and farming practices that could support the return of birds to farmland, i.e. the required fine-tuning of management practices. As a consequence, the existing agri-environmental schemes that offer financial compensation to farmers for implementing generally simple and rather crude measures to stimulate the presence of birds have been limited in their effectiveness and subject to much debate. The objective of this paper is to provide a sociological appraisal of farmers' experiences with meadow bird protection in a mainly dairy farming area in the Netherlands. The methodology combined visual map analysis, surveys, interviews with farmers and experts, and monitoring farmers' discussions. The results allowed an assessment of (i) farmers' views on historical changes in bird numbers in the area and the current distribution of bird nests, (ii) locally adjusted, fine-tuned management practices that were considered to be promising for protecting bird nests, (iii) the importance of farm management with 'an eye for birds', i.e. farmers and/or birdwatchers paying additional attention to the presence of nests and chicks before carrying out farming activities, and (iv) the views of key experts in the socio-institutional network in the case study area. The paper concludes that there are various promising options for fine-tuning farm management so it offers better bird protection, but it is expected that such measures will predominantly be adopted on less intensively managed farms.
Assuntos
Agricultura/métodos , Aves , Conservação dos Recursos Naturais/métodos , Meio Ambiente , Animais , Humanos , Países Baixos , População , Fatores SocioeconômicosRESUMO
BACKGROUND: Questions about the international reliability and validity of aspects of psychopathy have been raised for adults, but hardly considered when applying the constructs to children. AIMS/OBJECTIVES: Our aim was to compare the psychometrics of a new instrument to measure psychopathic traits in children between two countries - the Netherlands and Greece. We also tested the hypothesis that, in both countries, both narcissistic-egocentric and callous-unemotional dimensions would be related to observed behavioural disorders. METHODS: The Social and Emotional Detachment Questionnaire was used to assess narcissistic-egocentric and callous-unemotional dimensions of personality in representative national and community samples of 4-12-year-old children in the Netherlands and Greece, respectively. Parents filled in the questionnaires anonymously and also provided ratings of conduct disorders. RESULTS: A two-dimensional construct of the psychopathic syndrome depicting, respectively, narcissistic and unemotional traits was reliable and valid in both countries, although there was considerable correlation between these two dimensions, which we designated 'social detachment' and 'emotional detachment', respectively. In both countries, the composite of social and emotional detachment was associated with aggressive and antisocial conduct disorders. CONCLUSIONS/IMPLICATIONS: The reliability, validity and predictive value of this questionnaire must be tested further, for example, through multiple informants and longitudinally, but our findings that the tool performs robustly in two very different European countries is encouraging in terms of its potential value as a clinical screening tool and a tool for furthering the understanding of serious behavioural disorders in children.
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Transtorno da Personalidade Antissocial/psicologia , Transtorno da Conduta/psicologia , Inquéritos e Questionários , Criança , Pré-Escolar , Comparação Transcultural , Feminino , Grécia , Humanos , Masculino , Países Baixos , Psicometria , Reprodutibilidade dos TestesRESUMO
The number of children displaying childhood disorders in the Netherlands is estimated through a questionnaire referencing DSM-IV symptoms filled out by the parents of 2,563 4- 18-year-old Dutch children randomly taken from the general Dutch Youth population in 2004. The number of impaired children was estimated by applying the DSM-IV criteria for impairment by symptoms. It was found that 14% of all Dutch children display developmental difficulties, with 8% at risk of moderate behavioral and emotional difficulties and 6% at risk of a childhood psychiatric disorder. These prevalence figures based upon parental observations of DSM-IV symptoms in children are in agreement with the findings of other studies estimating psychiatric disorders in childhood in Western countries.
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Transtorno do Deficit de Atenção com Hiperatividade/epidemiologia , Deficiências do Desenvolvimento/epidemiologia , Transtornos Mentais/epidemiologia , Pais , Adolescente , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Criança , Pré-Escolar , Deficiências do Desenvolvimento/diagnóstico , Manual Diagnóstico e Estatístico de Transtornos Mentais , Feminino , Humanos , Masculino , Transtornos Mentais/diagnóstico , Países Baixos/epidemiologia , Variações Dependentes do Observador , Reprodutibilidade dos TestesRESUMO
Bacteriophage M102 is a lytic phage specific for serotype c strains of Streptococcus mutans, a causative agent of dental caries. In this study, the complete genome sequence of M102 was determined. The genome is 31,147 bp in size and contains 41 ORFs. Most of the ORFs encoding putative phage structural proteins show similarity to those from bacteriophages from Streptococcus thermophilus. Bioinformatic analysis indicated that the M102 genome contains an unusual lysis cassette, which encodes a holin and two lytic enzymes.
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Genoma Viral/genética , Fagos de Streptococcus/genética , Streptococcus mutans/virologia , Sequência de Aminoácidos , Sequência de Bases , Dados de Sequência Molecular , Fases de Leitura Aberta/genética , Proteoma/genética , Fagos de Streptococcus/ultraestruturaRESUMO
Digital dermatitis is an inflammation of uncertain aetiology in the skin of the foot of cattle. In 2005, a novel microorganism, Guggenheimella bovis, was isolated from the advancing front of digital dermatitis lesions, suggesting a possible role in pathogenesis. In the present study, tissue samples of 20 affected cows were examined by quantitative PCR for G. bovis, treponemes and the total eubacterial load. High numbers of eubacteria and treponemes were found in most lesions, whereas only a few lesions contained Guggenheimella, and only at low concentrations. The results argue against the relevance of G. bovis in the aetiology of digital dermatitis in cattle, but are consistent with a role for treponemes.
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Bactérias/isolamento & purificação , Doenças dos Bovinos/microbiologia , Dermatite/veterinária , Treponema/isolamento & purificação , Animais , Bactérias/classificação , Bactérias/patogenicidade , Bovinos , Dermatite/microbiologia , Suíça , Treponema/classificação , Treponema/patogenicidadeRESUMO
BACKGROUND: In human breast cancers, amplification of chromosome 11q13 correlates with lymph node metastasis and increased mortality. To date, two genes located within this amplicon, CCND1 and EMS1, were considered to act as oncogenes, because overexpression of both proteins, respectively cyclin D1 and cortactin, correlated well with 11q13 amplification. Cyclin D1 is involved in cell cycle regulation and the F-actin-binding protein cortactin in cytoskeletal dynamics and cell migration. To study the role of cortactin in mammary gland tumorigenesis, we examined mouse mammary tumor virus (MMTV)-cortactin transgenic mice and MMTV-cortactin/-MMTV-cyclin D1 bitransgenic mice. METHODS: MMTV-cortactin transgenic mice were generated and intercrossed with previously described MMTV-cyclin D1 transgenic mice. Immunohistochemical, Northern and Western blot analyses were performed to study the expression of human transgene cortactin during mammary gland development and in mammary tumors. For tumor incidence studies, forced-bred, multiparous mice were used to enhance transgene expression in the mammary gland. Microscopical examination was performed using haematoxylin and eosin staining. RESULTS: Mammary gland tumors arose stochastically (incidence 21%) with a mean age of onset at 100 weeks. This incidence, however, did not exceed that of aged-matched control FVB/N mice (38%), which unexpectedly, also developed spontaneous mammary gland tumors. We mimicked 11q13 amplification by generating MMTV-cortactin/-MMTV-cyclin D1 bitransgenic mice but did not observe any synergistic effect of cortactin on cyclin D1-induced mammary hyperplasias or carcinomas, nor development of distant metastasis. CONCLUSION: From this study, we conclude that development of (pre-malignant) breast tumors in either wild type or MMTV-cyclin D1 mice was not augmented due to mammary gland targeted overexpression of human cortactin.
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Cortactina/genética , Neoplasias Mamárias Experimentais/genética , Animais , Cortactina/análise , Cortactina/fisiologia , Ciclina D1/genética , Feminino , Expressão Gênica , Marcação de Genes , Humanos , Glândulas Mamárias Animais/anatomia & histologia , Glândulas Mamárias Animais/metabolismo , Glândulas Mamárias Animais/patologia , Neoplasias Mamárias Experimentais/patologia , Vírus do Tumor Mamário do Camundongo/genética , Camundongos , Camundongos Transgênicos , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/patologiaRESUMO
We developed quantitative fimA genotype assays and applied them in a pilot study investigating the fimbrial genotype distribution of Porphyromonas gingivalis in European subjects with or without chronic periodontitis. P. gingivalis was found in 71% and 9% of the samples from patients and healthy subjects, respectively. Enumeration of total P. gingivalis cell numbers by polymerase chain reaction and immunofluorescence showed excellent correspondence (r = 0.964). 73% of positive samples contained multiple fimA genotypes, but generally one genotype predominated by one to three orders of magnitude. Genotype II predominated in 60% of the samples. Genotype IV occurred with similar prevalence (73%) as genotype II but predominated in only 20% of the samples. Genotypes I, III and V were of much lower prevalence and cell densities of the latter two remained sparse. Our results suggest marked differences among the fimA genotypes' ability to colonize host sites with high cell numbers.
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Placa Dentária/microbiologia , Proteínas de Fímbrias/genética , Porphyromonas gingivalis/classificação , Porphyromonas gingivalis/genética , Adulto , Idoso , Contagem de Colônia Microbiana/métodos , DNA Bacteriano/isolamento & purificação , Feminino , Imunofluorescência , Genes Bacterianos , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Periodontite/microbiologia , Projetos Piloto , Reação em Cadeia da Polimerase/métodos , Polimorfismo GenéticoRESUMO
Increased attention for indigenous rights in relation to nature conservation has in the Philippines resulted in legislation formalizing indigenous peoples' participation in protected area management. We discuss the implementation of this legislation, based on the case of the Agta inhabiting the Northern Sierra Madre Natural Park. The Agta are hunter-gatherers who settle along the coasts and rivers of northeast Luzon. Being indigenous to the park, they hold one third of the seats in its management board. However, our content analysis of this management board's meetings, combined with qualitative observations of the Agta's position in the park, show that their participation in its management is hampered by socio-cultural, practical, financial and political barriers. We demonstrate that formalizing indigenous participation in protected area management is not enough to break through existing power structures that inhibit marginalized stakeholders to defense of their interests in natural resources against those of more powerful actors.
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Host and vector distribution of Trypanosoma brucei gambiense was studied in relation to habitat types and seasons. Six (19.35%) of the 31 mammal species recorded in Bipindi were reservoir hosts. Cercopithecus nictitans was confined to the undisturbed forest and the low intensive shifting cultivation zones, while Cephalophus monticola, Cephalophus dorsalis, Cricetomys gambianus, Atherurus africanus and Nandinia binotata occurred in all the habitat types. As for vectors of human African trypanosomiasis (HAT), Glossina palpalis palpalis, was the most abundant (99.13%) among tsetse fly species. It occurs in all biotopes with its highest density recorded in the village-adjacent forest. The village-adjacent forest is therefore the most risky transmission zone for HAT mainly during the short rainy season when G. palpalis palpalis' density is highest (2.91); while, the high and low intensive shifting cultivation zones are the most important contact zones between humans, G. palpalis palpalis and wild mammals in all seasons.
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Reservatórios de Doenças , Vetores de Doenças , Trypanosoma brucei gambiense/isolamento & purificação , Tripanossomíase Africana/epidemiologia , Animais , Camarões/epidemiologia , Demografia , Ecossistema , Mamíferos/parasitologia , Roedores/parasitologia , Ruminantes/parasitologia , Estações do Ano , Árvores , Moscas Tsé-Tsé/parasitologiaRESUMO
Clustered regularly interspaced short palindromic repeats (CRISPR) consist of highly conserved direct repeats interspersed with variable spacer sequences. They can protect bacteria against invasion by foreign DNA elements. The genome sequence of Streptococcus mutans strain UA159 contains two CRISPR loci, designated CRISPR1 and CRISPR2. The aims of this study were to analyse the organization of CRISPR in further S. mutans strains and to investigate the importance of CRISPR in acquired immunity to M102-like phages. The sequences of CRISPR1 and CRISPR2 arrays were determined for 29 S. mutans strains from different persons. More than half of the CRISPR1 spacers and about 35 % of the CRISPR2 spacers showed sequence similarity with the genome sequence of M102, a virulent siphophage specific for S. mutans. Although only a few spacers matched the phage sequence completely, most of the mismatches had no effect on the amino acid sequences of the phage-encoded proteins. The results suggest that S. mutans is often attacked by M102-like bacteriophages, and that its acquisition of novel phage-derived CRISPR sequences goes along with the presence of S. mutans phages in the environment. Analysis of CRISPR1 of M102-resistant mutants of S. mutans OMZ 381 showed that some of them had acquired novel spacers, and the sequences of all but one of these matched the phage M102 genome sequence. This suggests that the acquisition of the spacers contributed to the resistance against phage infection. However, since not all resistant mutants had new spacers, and since the removal of the CRISPR1 array in one of the mutants and in wild-type strains did not lead to loss of resistance to infection by M102, the acquisition of resistance must be based on further elements as well.
Assuntos
Sequências Repetidas Invertidas/imunologia , Fagos de Streptococcus/imunologia , Streptococcus mutans , Sequência Conservada/imunologia , DNA Bacteriano/análise , DNA Bacteriano/genética , DNA Intergênico/análise , DNA Intergênico/genética , DNA Viral/análise , DNA Viral/genética , Mutação da Fase de Leitura , Inativação Gênica , Genes Bacterianos , Alinhamento de Sequência , Análise de Sequência de DNA , Streptococcus mutans/genética , Streptococcus mutans/imunologiaRESUMO
Bacteriophage M102 is a virulent siphophage that propagates in some serotype c Streptococcus mutans strains, but not in S. mutans of serotype e, f or k. The serotype of S. mutans is determined by the glucose side chain of rhamnose-glucose polysaccharide (RGP). Because the first step in the bacteriophage infection process is adsorption of the phage, it was investigated whether the serotype specificity of phage M102 was determined by adsorption. M102 adsorbed to all tested serotype c strains, but not to strains of different serotypes. Streptococcus mutans serotype c mutants defective in the synthesis of the glucose side chain of RGP failed to adsorb phage M102. These results suggest that the glucose side chain of RGP acts as a receptor for phage M102.