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1.
Phytopathology ; : PHYTO06230200KC, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-37581424

RESUMO

Aflatoxins are carcinogens produced by the fungi Aspergillus flavus and A. parasiticus that contaminate pistachio crops. International markets reject pistachio when aflatoxins exceed permitted maximum levels. Releasing the atoxigenic strain AF36 of A. flavus is the leading aflatoxin pre-harvest control method. The product AF36 Prevail, sorghum grains coated with AF36 propagules, has been used in California since 2017. However, a high percentage of grains of the Prevail fail to sporulate in orchards. Here, the effect of soil moisture on the percentage of AF36 product grains sporulating (SG) and the quantity of spores per grain using a sporulation index (SI) was determined. Under controlled conditions, SG was higher than 85% when soil moisture was 13% or more, and SI increased with increasing soil moisture from 8.4 to 21%. The highest AF36 sporulation occurred near the micro-sprinklers when the grains were not impacted by the irrigation water drops. Arthropod predation was responsible for lost product grains, which was more pronounced in non-tilled soil than in tilled soil. Dispersal of the AF36 spores decreased markedly with the height and distance from the inoculum source, following a pattern of diffusion equations. However, AF36 spores easily reached canopies of pistachios located 10 m from the inoculum source. Our results indicate that AF36 Prevail should be applied close to the irrigation line in the moist soil area but avoiding the areas where excess irrigation causes water accumulation. The biocontrol of aflatoxins in California's pistachio production areas was optimized by improving the field realization of the biological control agent.

2.
Plant Dis ; 2024 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-39393075

RESUMO

Anthracnose, the most critical fruit disease affecting olive crops, necessitates the evaluation of the susceptibility of traditional and new varieties. In Spain and Portugal, Anthracnose is caused by several Colletotrichum species, with C. godetiae and C. nymphaeae being dominant and C. acutatum and C. fioriniae being secondary. This study explores the susceptibility of fruits from an F1 progeny resulting from a cross between 'Picual' (resistant) and 'Arbequina' (moderately susceptible) cultivars to C. godetiae. While most genotypes showed resistance levels comparable to their parents, seven showed a 50% reduction in disease severity compared to 'Picual.' The normal distribution of genotypes' response to the pathogen suggests a complex resistance mechanism. Furthermore, we assessed the susceptibility of four traditional cultivars, two new cultivars ('Sikitita-2' and 'Martina'), and five advanced selections (pre-commercial genotypes) to C. godetiae and C. nymphaeae. Despite the significant interaction between the olive genotype and Colletotrichum species in this experiment, the new cultivars and advanced selections were classified as susceptible or moderately susceptible against both species. A subsequent analysis of the interaction between 'Picual' (resistant) and 'Hojiblanca' (susceptible) fruits with the four mentioned Colletotrichum species revealed significant differences among cultivars but no interaction between genotype and pathogen species. Colletotrichum species were categorized as follows: i) C. godetiae and C. nymphaeae as highly virulent, ii) C. acutatum as moderately virulent, and iii) C. fioriniae as weakly virulent. Finally, C. nymphaeae exhibited an enhanced ability to infect and develop acervuli in olive leaves, potentially serving as an inoculum source for this species. The absence of a correlation between leaf and fruit susceptibilities to the pathogen suggests differences in resistance mechanisms. In conclusion, this study provides valuable insights into the complex interactions between olive genotype and Colletotrichum species, essential for cultivar selection and understanding the disease cycle.

3.
Plant Dis ; 107(6): 1777-1784, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36401847

RESUMO

Aflatoxins are carcinogens mainly produced by Aspergillus flavus and A. parasiticus in susceptible crops, including pistachio. The primary inoculum sources of these pathogens are plant debris in the orchard soils. In Californian fields, one approach to controlling aflatoxin contamination is based on releasing the atoxigenic strain of A. flavus AF36 in inoculated (coated) sorghum grains (AF36 Prevail). However, this control method can fail due to poor sporulation of the AF36 strain or sorghum grain losses due to predation. In 2008 and 2018, we showed that toxigenic and atoxigenic isolates of Aspergillus spp. frequently colonized fallen inflorescences of male pistachio trees. Under controlled conditions, strain AF36 profusely colonized pistachio male inflorescences when humidity was higher than 90%. However, there were significant differences between types of inflorescence (aerial > fallen). In 2016, we considerably (P = 0.015) increased the population of AF36 on the canopies of trees when fallen inflorescences were inoculated with AF36, compared with untreated trees. In 2017 and 2018, these differences were not detected (P > 0.05) due to cross-contamination of strain AF36 between seasons and neighboring plots. In any case, the density of AF36 spores on the canopy of the inflorescence-treated trees was similar (P > 0.05) to that on trees treated with the commercial product. Here, we present a new method for applying strain AF36 based on using a natural, abundant, and uniformly distributed substrate in pistachio fields, and we discuss how it can be improved. Furthermore, our results indicate that, in pistachio orchards where biocontrol practices are not conducted, eliminating this important source of toxigenic Aspergillus inoculum is recommended.


Assuntos
Aflatoxinas , Pistacia , Aspergillus flavus , Inflorescência/química , Aflatoxinas/análise , Aspergillus , Grão Comestível/química , Árvores
4.
Plant Dis ; 106(2): 504-509, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34569835

RESUMO

Aflatoxin contamination of almond kernels, caused by Aspergillus flavus and A. parasiticus, is a severe concern for growers because of its high toxicity. In California, the global leader of almond production, aflatoxin can be managed by applying the biological control strain AF36 of A. flavus and selecting resistant cultivars. Here, we classified the almond genotypes by K-Means cluster analysis into three groups (susceptible [S], moderately susceptible [MS], or resistant [R]) based on aflatoxin content of inoculated kernels. The protective effects of the shell and seedcoat in preventing aflatoxin contamination were also examined. The presence of intact shells reduced aflatoxin contamination >100-fold. The seedcoat provided a layer of protection but not complete protection. In kernel inoculation assays, none of the studied almond genotypes showed a total resistance to the pathogen. However, nine traditional cultivars and four advanced selections were classified as R. Because these advanced selections contained germplasm derived from peach, we compared the kernel resistance of three peach cultivars to that shown by kernels of an R (Sonora) and an S (Carmel) almond cultivar and five pistachio cultivars. Overall, peach kernels were significantly more resistant to the pathogen than almond kernels, which were more resistant than pistachio kernels. Finally, we studied the combined effect of the cultivar resistance and the biocontrol strain AF36 in limiting aflatoxin contamination. For this, we coinoculated almond kernels of R Sonora and S Carmel with AF36 72 h before or 48 h after inoculating with an aflatoxin-producing strain of A. flavus. The percentage of aflatoxin reduction by AF36 strain was greater in kernels of Carmel (98%) than in those of Sonora (83%). Cultivar resistance also affected the kernel colonization by the biological control strain. AF36 strain limited aflatoxin contamination in almond kernels even when applied 48 h after the aflatoxin-producing strain. Our results show that biocontrol combined with the use of cultivars with resistance to aflatoxin contamination can result in a more robust protection strategy than the use of either practice in isolation.


Assuntos
Aflatoxinas , Prunus dulcis , Aspergillus/genética , Aspergillus flavus/genética
5.
Plant Dis ; 105(6): 1657-1665, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33084543

RESUMO

The species Aspergillus flavus and A. parasiticus are commonly found in the soils of nut-growing areas in California. Several isolates can produce aflatoxins that occasionally contaminate nut kernels, conditioning their sale. Strain AF36 of A. flavus, which does not produce aflatoxins, is registered as a biocontrol agent for use in almond, pistachio, and fig crops in California. After application in orchards, AF36 displaces aflatoxin-producing Aspergillus spp. and thus reduces aflatoxin contamination. Vegetative compatibility assays (VCAs) have traditionally been used to track AF36 in soils and crops where it has been applied. However, VCAs are labor intensive and time consuming. Here, we developed a quantitative real-time PCR (qPCR) protocol to quantify proportions of AF36 accurately and efficiently in different substrates. Specific primers to target AF36 and toxigenic strains of A. flavus and A. parasiticus were designed based on the sequence of aflC, a gene essential for aflatoxin biosynthesis. Standard curves were generated to calculate proportions of AF36 based on threshold cycle values. Verification assays using pure DNA and conidial suspension mixtures demonstrated a significant relationship by regression analysis between known and qPCR-measured AF36 proportions in DNA (R2 = 0.974; P < 0.001) and conidia mixtures (R2 = 0.950; P < 0.001). Tests conducted by qPCR in pistachio leaves, nuts, and soil samples demonstrated the usefulness of the qPCR method to precisely quantify proportions of AF36 in diverse substrates, ensuring important time and cost savings. The outputs of this study will serve to design better aflatoxin management strategies for pistachio and other crops.


Assuntos
Aflatoxinas , Pistacia , Aflatoxinas/análise , Aspergillus flavus/genética , Nozes , Folhas de Planta/química , Reação em Cadeia da Polimerase em Tempo Real , Solo
6.
Biochim Biophys Acta ; 1859(5): 731-43, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27001033

RESUMO

The RPB1 mutants in the foot region of RNA polymerase II affect the assembly of the complex by altering the correct association of both the Rpb6 and the Rpb4/7 dimer. Assembly defects alter both transcriptional activity as well as the amount of enzyme associated with genes. Here, we show that the global transcriptional analysis of foot mutants reveals the activation of an environmental stress response (ESR), which occurs at a permissive temperature under optimal growth conditions. Our data indicate that the ESR that occurs in foot mutants depends mostly on a global post-transcriptional regulation mechanism which, in turn, depends on Rpb4-mRNA imprinting. Under optimal growth conditions, we propose that Rpb4 serves as a key to globally modulate mRNA stability as well as to coordinate transcription and decay. Overall, our results imply that post-transcriptional regulation plays a major role in controlling the ESR at both the transcription and mRNA decay levels.


Assuntos
RNA Polimerase II/genética , Proteínas de Saccharomyces cerevisiae/genética , Estresse Fisiológico/genética , Transcrição Gênica , Impressão Molecular , Mutação , Estabilidade de RNA/genética , RNA Mensageiro/genética , Saccharomyces cerevisiae
7.
Anaerobe ; 47: 33-38, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28389412

RESUMO

BACKGROUND: Infective endocarditis (IE) caused by anaerobic bacteria is a rare and poorly characterized disease. Most data reported in the literature are from case reports [1-3]. Therefore, we assessed the situation of anaerobic IE (AIE) in Spain using the database of the Spanish Collaboration on Endocarditis (GAMES). METHODS: We performed a prospective study from 2008 to 2016 in 26 Spanish centers. We included 2491 consecutive cases of definite IE (Duke criteria). RESULTS: Anaerobic bacteria caused 22 cases (0.9%) of definite IE. Median age was 66 years (IQR, 56-73), and 19 (86.4%) patients were men. Most patients (14 [63.6%]) had prosthetic valve IE and all episodes were left-sided: aortic valves, 12 (54.5%); and mitral valves, 8 (36.4%). The most common pathogens were Propionibacterium acnes (14 [63.6%]), Lactobacillus spp (3 [13.63%]), and Clostridium spp. (2 [9.0%]), and the infection was mainly odontogenic. Fifteen of the 22 patients (68.2%) underwent cardiac surgery. Mortality was 18.2% during admission and 5.5% after 1 year of follow-up. When patients with AIE were compared with the rest of the cohort, we found that although those with AIE had a similar age and Charlson comorbidity index, they were more likely to have community-acquired IE (86.4% vs. 60.9%, p = 0.01), have undergone cardiac surgery (68.2% vs 48.7% p = 0.06), and have had lower mortality rates during admission (18.2% vs. 27.3%). CONCLUSION: IE due to anaerobic bacteria is an uncommon disease that affects mainly prosthetic valves and frequently requires surgery. Otherwise, there are no major differences between AIE and IE caused by other microorganisms.


Assuntos
Bactérias Anaeróbias/classificação , Bactérias Anaeróbias/isolamento & purificação , Endocardite Bacteriana/epidemiologia , Endocardite Bacteriana/microbiologia , Infecções Relacionadas à Prótese/epidemiologia , Infecções Relacionadas à Prótese/microbiologia , Idoso , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Prospectivos , Espanha/epidemiologia
8.
Eur J Clin Microbiol Infect Dis ; 35(5): 821-8, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26951263

RESUMO

Pathogenic factors of Staphylococcus aureus (SA) in the development of infective endocarditis (IE) have not been sufficiently investigated. The purpose of this study was to analyze the pathogenesis and virulence factors of SA in patients with IE as compared to patients with uncomplicated bacteremia (un-BAC). This is a retrospective case-control study (2002-2014) performed at a tertiary hospital in Spain. Clinical and epidemiological factors were analyzed. We assessed the presence of toxin genes [toxic shock syndrome toxin 1 (tst-1) and enterotoxins A (etA), B (etB), and D (etD)] and the potential relationship between accessory gene regulator (agr) groups and the development of IE confirmed by polymerase chain reaction (PCR). Twenty-nine patients with IE were compared with 58 patients with uncomplicated S. aureus bacteremia (SAB). As many as 75.9 % of patients had community-acquired IE (p < 0.005). Multivariate analysis revealed that there is a significant relationship between community-acquired infection and severe sepsis or septic shock and IE. Also, a minimum inhibitory concentration (MIC) of vancomycin ≥1.5 µg/ml was found to be associated with IE. The agr group I was prevalent (55.2 % vs. 31.0 %; p = 0.030). No association was observed between toxin genes (tst-1, etA, etB, and etD) and IE. The superantigen (SAg) most frequently found in SA isolates was tst-1 (12.6 %). We found no association between toxin genes and IE, probably due to the small sample size. However, a direct relationship was found between agr I and the development of IE, which suggests that agr I strains may have more potential to cause IE.


Assuntos
Bacteriemia/diagnóstico , Bacteriemia/microbiologia , Endocardite Bacteriana/diagnóstico , Endocardite Bacteriana/microbiologia , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Estudos de Casos e Controles , Comorbidade , Farmacorresistência Bacteriana , Endocardite Bacteriana/complicações , Endocardite Bacteriana/mortalidade , Feminino , Genes Bacterianos , Genótipo , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Staphylococcus aureus/efeitos dos fármacos , Resultado do Tratamento , Fatores de Virulência/genética
9.
Rev Enferm ; 39(9): 44-8, 2016 09.
Artigo em Espanhol | MEDLINE | ID: mdl-30252230

RESUMO

Introduction: The purpose of this study is to find the user opinion regarding the active patient dynamics, to analyze if the users think that their knowledge increased after taking part in the group education and to determine if they think that what they have learnt will help them modify their daily habits. Material and Methods: Phenomenological qualitative study. Participants: patients older than 14 years of age without cognitive impairment. Registering techniques: survey and field notes. The software NVIVO was used to analyze the results. Results: The active patient dynamics were positively valued by the participants, specially the following categories: attention, participation, personal resolutions, opinions, suggestions and recommendations. 74% of participants deemed their knowledge to have increased substantially and 52% expressed that the lessons learnt will help them modify their daily habits. Discussion and Conclusions: The Spanish department of health has a strategy to empower patients to take a more active role in their health through the Active Patient Therapy. This study concurs with it and it is positively valued by the users. This type of education is increasingly demanded and the nursing community is an ideal position to enlighten the population. The majority of participants thought that the lessons learnt will help them modify their daily habits. It would be interesting to analyze the realization of those resolutions in other workshops or as a follow-up in the nursing consults to reach healthy goals.


Assuntos
Atitude Frente a Saúde , Educação de Pacientes como Assunto , Participação do Paciente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Processos Grupais , Humanos , Masculino , Pessoa de Meia-Idade , Pesquisa Qualitativa , Adulto Jovem
10.
Chemistry ; 21(6): 2489-500, 2015 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-25522111

RESUMO

Enantiopure ß-amino acids represent interesting scaffolds for peptidomimetics, foldamers and bioactive compounds. However, the synthesis of highly substituted analogues is still a major challenge. Herein, we describe the spontaneous rearrangement of 4-carboxy-2-oxoazepane α,α-amino acids to lead to 2'-oxopiperidine-containing ß(2,3,3) -amino acids, upon basic or acid hydrolysis of the 2-oxoazepane α,α-amino acid ester. Under acidic conditions, a totally stereoselective synthetic route has been developed. The reordering process involved the spontaneous breakdown of an amide bond, which typically requires strong conditions, and the formation of a new bond leading to the six-membered heterocycle. A quantum mechanical study was carried out to obtain insight into the remarkable ease of this rearrangement, which occurs at room temperature, either in solution or upon storage of the 4-carboxylic acid substituted 2-oxoazepane derivatives. This theoretical study suggests that the rearrangement process occurs through a concerted mechanism, in which the energy of the transition states can be lowered by the participation of a catalytic water molecule. Interestingly, it also suggested a role for the carboxylic acid at position 4 of the 2-oxoazepane ring, which facilitates this rearrangement, participating directly in the intramolecular catalysis.

11.
Crit Rev Food Sci Nutr ; 55(4): 521-51, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-24915368

RESUMO

Hypertension is one of the main causes of cardiovascular diseases. Synthetic drugs inhibiting ACE activity present high effectiveness in the treatment of hypertension but cause undesirable side effects. Unlike these synthetic drugs, antihypertensive peptides do not show any adverse effect. These peptides are naturally present in some foods and since hypertension is closely related to modern diet habits, the interest for this kind of foods is increasing. Different methods for the purification, isolation, and characterization of antihypertensive peptides in foods have been developed. Nevertheless, there is no revision work summarizing and comparing these strategies. In this review, in vivo and in vitro pathways to obtain antihypertensive peptides have been summarized. The ACE mechanism and the methodologies developed to assay the ACE inhibitory activity have also been described. Moreover, a comprehensive overview on the isolation, purification, and identification techniques focusing on the discovery of new antihypertensive peptides with high activity has been included. Finally, it is worthy to highlight that the quantitation of antihypertensive peptides in foods is a new trend since genotype and processing conditions could affect their presence. Analytical methodologies using mass spectrometry constitute an interesting option for this purpose.


Assuntos
Anti-Hipertensivos/isolamento & purificação , Anti-Hipertensivos/farmacologia , Alimentos , Hipertensão/dietoterapia , Peptídeos/química , Sequência de Aminoácidos , Anti-Hipertensivos/química , Análise de Alimentos/métodos , Humanos , Espectrometria de Massas/métodos , Peptídeos/isolamento & purificação , Peptídeos/farmacologia , Relação Estrutura-Atividade
12.
Org Biomol Chem ; 13(18): 5195-201, 2015 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-25849279

RESUMO

A suitably protected Orn-derived (3S,4S)-ß-lactam was used as common intermediate in the synthesis of conformationally constrained (3S,4S)-2-oxoazepane α,α- and (2S,3S)-2-oxopiperidine-ß(2,3,3)-amino acid derivatives. Compared to alternative procedures using an N-p-methoxybenzyl group at the 2-azetidinone, the incorporation of a p-methoxyphenyl moiety is crucial for the excellent stereochemical outcomes in the preparation of these heterocyclic amino acids. Chemoselective 7- or 6-exo-trig cyclization was achieved through alternative sequences of Pmp-deprotection/Boc-activation, followed by inter- and intramolecular ß-lactam ring opening, respectively.


Assuntos
Aminoácidos/química , Compostos Heterocíclicos/química , beta-Lactamas/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Espectroscopia de Prótons por Ressonância Magnética , Espectrometria de Massas por Ionização por Electrospray , Estereoisomerismo
13.
BMC Geriatr ; 15: 134, 2015 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-26499459

RESUMO

BACKGROUND: An early detection of memory loss may hold great value as a predictor for dementia. Dementia has already been associated with higher risk of hip fracture. Our aim was to examine the prospective association between self-reported memory-loss and the risk of subsequent hip fracture in the elderly. METHODS: A population-based prospective cohort study design was used. Information on four self-perceived memory loss questions was obtained from questionnaires in 3 health surveys performed in Norway during the years 2000-2001. A total of 7154 men and 2462 women aged 67-77 years old were followed for a median of 7.8 years. Hip fracture information (n = 287 in men, and n = 237 in women) was obtained from NORHip (a database including all hip fractures treated in Norway from year 1994). Cox survival analysis was performed to estimate HR (hazard ratio). RESULTS: The risk of sustaining a hip fracture were higher in those who reported to forget things they had just heard or read, with a HR of 1.52 (1.19--1.95) in men and HR 1.60 (1.23--2.07) in women after adjustment for relevant confounders. Women reporting to forget where they had put things also had higher risk of later hip fracture with a HR of 1.58 (1.20--2.07). Answering yes in both questions showed stronger association with sustaining a first hip fracture compared with those who gave a negative response in both questions, with a multivariate adjusted HR of 1.41 (IC 95 % 1.06--1.88) in men and 1.90 (IC 95 % 1.39--2.60) in women. The two last questions did not show a significant association with hip fracture. CONCLUSIONS: There was a higher risk of hip fracture in elderly who reported self-perceived memory loss. Due to the serious implications of sustaining a hip fracture, early detection of risk groups is important for preventive interventions.


Assuntos
Fraturas do Quadril/diagnóstico , Fraturas do Quadril/epidemiologia , Transtornos da Memória/diagnóstico , Transtornos da Memória/epidemiologia , Vigilância da População , Autoimagem , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Seguimentos , Fraturas do Quadril/psicologia , Humanos , Masculino , Transtornos da Memória/psicologia , Noruega/epidemiologia , Vigilância da População/métodos , Estudos Prospectivos , Fatores de Risco
14.
Molecules ; 19(4): 4814-46, 2014 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-24743938

RESUMO

A series of Phe-Gly dipeptide-derived piperazinones containing an aromatic urea moiety and a basic amino acid has been synthesized and evaluated as inhibitors of human platelet aggregation induced by the PAR1 agonist SFLLRN and as cytotoxic agents in human cancer cells. The synthetic strategy involves coupling of a protected basic amino acid benzyl amide to 1,2- and 1,2,4-substituted-piperazinone derivatives, through a carbonylmethyl group at the N1-position, followed by formation of an aromatic urea at the exocyclic moiety linked at the C2 position of the piperazine ring and removal of protecting groups. None of the compounds showed activity in the biological evaluation.


Assuntos
Dipeptídeos/química , Peptidomiméticos/química , Piperazinas/química , Inibidores da Agregação Plaquetária/química , Receptor PAR-1/química , Humanos , Fragmentos de Peptídeos/química , Peptidomiméticos/síntese química , Agregação Plaquetária , Inibidores da Agregação Plaquetária/síntese química , Receptor PAR-1/antagonistas & inibidores , Estereoisomerismo , Trombina/química , Ureia/química
15.
Sci Rep ; 13(1): 5344, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-37005485

RESUMO

Olive anthracnose, a critical olive fruit disease that adversely impacts oil quality, is caused by Colletotrichum species. A dominant Colletotrichum species and several secondary species have been identified in each olive-growing region. This study surveys the interspecific competition between C. godetiae, dominant in Spain, and C. nymphaeae, prevalent in Portugal, to shed light on the cause of this disparity. When Petri-dishes of Potato Dextrose Agar (PDA) and diluted PDA were co-inoculated with spore mixes produced by both species, C. godetiae displaced C. nymphaeae, even if the percentage of spores in the initial spore mix inoculation was just 5 and 95%, respectively. The C. godetiae and C. nymphaeae species showed similar fruit virulence in separate inoculations in both cultivars, the Portuguese cv. Galega Vulgar and the Spanish cv. Hojiblanca, and no cultivar specialization was observed. However, when olive fruits were co-inoculated, the C. godetiae species showed a higher competitive ability and partially displaced the C. nymphaeae species. Furthermore, both Colletotrichum species showed a similar leaf survival rate. Lastly, C. godetiae was more resistant to metallic copper than C. nymphaeae. The work developed here allows a deeper understanding of the competition between C. godetiae and C. nymphaeae, which could lead to developing strategies for more efficient disease risk assessment.


Assuntos
Colletotrichum , Olea , Doenças das Plantas , Frutas
16.
Sci Total Environ ; 903: 166591, 2023 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-37634721

RESUMO

Tree ring records are among the most valuable resources to create high-resolution climate reconstructions. Most climate reconstructions are based on old trees growing in inaccessible mountainous areas with low human activity. Therefore, reconstruction of climate conditions in lowlands is usually based on data from distant mountains. Albeit old trees can be common in humanized areas, they are not used for climate reconstructions. Pollarding was a common traditional management in Europe that enabled trees to maintain great vitality for periods exceeding the longevity of unmanaged trees. We evaluate the potential of pollarded deciduous oaks to record past climate signal. We sampled four pollarded woodlands in Central Spain under continental Mediterranean climate. We hypothesized that pollarded trees have a strong response to water availability during current period without pollarding management, but also in the period under traditional management if pruning was asynchronous among trees. Moreover, we hypothesized that if climate is a regional driver of oak secondary growth, chronologies from different woodlands will be correlated. Pollard oaks age exceeded 500 years with a strong response to Standardized Precipitation-Evapotranspiration Index (SPEI) from 9 to 11 months. Climate signal was exceptionally high in three of the sites (r2 = 0.443-0.655) during low management period (1962-2022). The largest fraction of this climate signal (≈70 %) could be retrieved during the traditional management period (1902-1961) in the three sites where pollarding was asynchronous. Chronologies were significantly correlated since the 19th century for all the studied period, highlighting a shared climate forcing. We identified critical points to optimize pollard tree sampling schema. Our results show the enormous potential of pollarded woodlands to reconstruct hydroclimate conditions in the Mediterranean with a fine spatial grain. Studying pollarded trees is an urgent task, since the temporal window to retrieve the valuable information in pollarded trees is closing as these giants collapse and their wood rots.

17.
J Org Chem ; 77(21): 9833-9, 2012 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-23057671

RESUMO

A simple method for the synthesis of an azepane quaternary amino acid in enantiopure form is described. Theoretical, NMR, and X-ray studies indicated that this azepane-derived amino acid is an effective stabilizer of 3(10) helical structures in short peptides.


Assuntos
Aminoácidos/química , Azepinas/química , Peptídeos/química , Sequência de Aminoácidos , Cristalografia por Raios X , Ligação de Hidrogênio , Conformação Molecular , Ressonância Magnética Nuclear Biomolecular , Estrutura Secundária de Proteína
18.
Bioorg Med Chem Lett ; 22(1): 444-8, 2012 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-22119467

RESUMO

Based on ß-turn-like BDNF loops 2 and 4, involved in receptor interaction, cyclic peptide replicas were designed, synthesized and tested. In addition to the native turn residues, the cyclic peptides include a linker unit between the N- and C-termini, selected by molecular modeling among various non-proteinogenic cyclic amino acids. NMR conformational studies showed that most of the cyclic peptides were able to adopt turn-like structures. Several of the analogues displayed significant inhibition of the BDNF-induced TrkB receptor phosphorylation, and hence could be useful templates for developing improved antagonists for this receptor.


Assuntos
Aminoácidos Cíclicos/química , Fator Neurotrófico Derivado do Encéfalo/química , Receptor trkB/química , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Desenho de Fármacos , Humanos , Espectroscopia de Ressonância Magnética/métodos , Modelos Químicos , Conformação Molecular , Peptídeos/química , Peptídeos Cíclicos/química , Fosforilação , Conformação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Temperatura
19.
J Dairy Sci ; 95(4): 1639-44, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22459812

RESUMO

The prevalence of coagulase-positive staphylococci (CPS) was studied among 390 samples of ewe milk. Fifty-seven (14.85%) samples of tank milk and all samples (6) of silo milk gave a positive result on Baird-Parker agar base supplemented with rabbit plasma fibrinogen, whereas amplification of the coagulase (coa) gene was successful in 6 (1.56%) samples of tank milk and in all silo samples. Phenotypic and genetic analysis of 153 isolates identified 151 (98.69%) as Staphylococcus aureus. Amplification of the coa gene was positive for 149 isolates (97.39%). The staphylococcal enterotoxin (SE) C gene was detected in 116 strains (75.82%), whereas more than one SE gene was carried in 5 strains (3.26%). None of the isolates harbored the genes for SEE or for methicillin resistance. A high prevalence of CPS carrying enterotoxin genes should be of concern because ewe milk is mainly processed into raw milk cheeses. The detection of the coa gene from milk samples could help to assess the microbiological safety of raw milk intended for direct use in the dairy industry.


Assuntos
Coagulase/análise , Leite/microbiologia , Ovinos/microbiologia , Staphylococcus aureus/isolamento & purificação , Animais , Coagulase/genética , DNA Bacteriano/análise , Enterotoxinas/análise , Feminino , Fenótipo , Reação em Cadeia da Polimerase/veterinária , Espanha , Staphylococcus aureus/classificação , Staphylococcus aureus/enzimologia
20.
J Org Chem ; 76(16): 6592-603, 2011 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-21718065

RESUMO

To explore further the chemistry of amino acid-derived ß-lactams, their conversion to α,α-heterocyclic quaternary amino acid derivatives is investigated. The latter derivatives, containing 2-oxoazepane as the α,α-substituent, are synthesized by a simple Pd-C-catalyzed hydrogenolysis of Orn(Z)-derived 2-azetidinones. The rearrangement from four- to seven-membered lactam ring is driven by the key intramolecular opening of the 1-Boc-ß-lactam, initiated by 7-exotrig ring closure from the NH(2) of the Orn side chain. The synthetic route is applied to the stereoselective preparation of enantiomerically pure 4-amino-3-methyl-2-oxoazepane-4-carboxylate derivatives, for which the structure and configuration is confirmed by X-ray diffraction. Molecular modeling and NMR experiments indicate that these quaternary amino acids are able to drive the adoption of ß-turn secondary structures when incorporated in model dipeptide derivatives.


Assuntos
Aminoácidos/química , Azepinas/química , Azepinas/síntese química , Ácidos Carboxílicos/química , Ácidos Carboxílicos/síntese química , Dipeptídeos/química , Oligopeptídeos/química , Oligopeptídeos/síntese química , Ornitina/química , Oxazepinas/química , beta-Lactamas/química , Catálise , Difração de Raios X
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