Checagem da pureza genética de amostras de café bourbon por meio de marcador microssatélite.

O grupo Bourbon se destaca dentre as cultivares de café arábica pelas suas características sensoriais superiores e maior valorização no mercado. Além da origem, da sustentabilidade e dos aspectos físicos e sensoriais, a rastreabilidade dos cafés diferenciados é fundamental na valorização do produto final. Este trabalho avaliou a eficiência de um marcador de DNA do tipo microssatélite ou SSR, denominado LEG2, com o objetivo de diferenciar cultivares do grupo Bourbon das principais cultivares plantadas no Brasil. Após a identificação do polimorfismo, foram avaliados a repetibilidade da técnica, o perfil de amplificação em sementes e folhas e a análise de amostras de lavouras comerciais. Esse marcador diferencia o grupo Bourbon das demais cultivares IAC, à exceção de cultivares mais antigas e pouco plantadas no País, como Typica e Amarelo de Botucatu. As cultivares Tupi IAC 1669, do IAC, e Sabiá Tardio, da Fundação Procafé, também apresentam o mesmo alelo dos cafés do grupo Bourbon para o loco LEG2. Pela simplicidade e boa resolução da técnica, o SSR-LEG2 pode ser aplicado no controle de qualidade genética nas fases de pré e pós-melhoramento do cafeeiro, e também para checar a pureza genética de amostras comerciais de café Bourbon

Gene expression during response to nutrient deficiency in leaf-miner resistant and susceptible genotypes.

Several physiologic factors affect the defense response of coffee trees to the leaf-miner (Leucoptera coffeella), including nutrient availability during plant growth. Resistant coffee plants may exhibit leaf-miner infection when field nutritional status is critical. Knowledge of how biological mechanisms associated with transport of macronutrients and defense to leaf-miner infection interact may provide insights to elucidate the resistance response. In this study, we investigated the expression profile of genes from potassium and nitrogen metabolism, oxidative stress and defense response, in coffee seedlings submitted to limiting nutritional conditions. Young plants from both resistant and susceptible genotypes were irrigated with solutions containing variable macronutrients (N+K+, N+K-, NK+, NK-). After treatment, leaves were collected, total RNA extracted and gene expression was evaluated by qRT-PCR. All assessed genes exhibited differential expression between susceptible and resistant plants in response to nutritional stress. In addition, genes directly involved with defense mechanisms and oxidative stress exhibited the most significant expression differences when compared with genes from nutrient metabolism. These preliminary analyses suggest that regulation of nutrient up-take and/or transport may not play a central role during coffee response, and instead the activation of defense mechanisms is the initial response to low nutrient availabilit

Raman spectroscopy of graphene under ultrafast laser excitation

The equilibrium optical phonons of graphene are well characterized in terms of anharmonicity and electron–phonon interactions; however, their non-equilibrium properties in the presence of hot charge carriers are still not fully explored. Here we study the Raman spectrum of graphene under ultrafast laser excitation with 3 ps pulses, which trade off between impulsive stimulation and spectral resolution. We localize energy into hot carriers, generating non-equilibrium temperatures in the ~1700–3100 K range, far exceeding that of the phonon bath, while simultaneously detecting the Raman response. The linewidths of both G and 2D peaks show an increase as function of the electronic temperature. We explain this as a result of the Dirac cones’ broadening and electron–phonon scattering in the highly excited transient regime, important for the emerging field of graphene-based photonics and optoelectronics

Raman spectroscopy of graphene under ultrafast laser excitation.

The equilibrium optical phonons of graphene are well characterized in terms of anharmonicity and electron-phonon interactions; however, their non-equilibrium properties in the presence of hot charge carriers are still not fully explored. Here we study the Raman spectrum of graphene under ultrafast laser excitation with 3 ps pulses, which trade off between impulsive stimulation and spectral resolution. We localize energy into hot carriers, generating non-equilibrium temperatures in the ~1700-3100 K range, far exceeding that of the phonon bath, while simultaneously detecting the Raman response. The linewidths of both G and 2D peaks show an increase as function of the electronic temperature. We explain this as a result of the Dirac cones' broadening and electron-phonon scattering in the highly excited transient regime, important for the emerging field of graphene-based photonics and optoelectronics

Effects of somatic embryogenesis on gene expression of cloned coffee heterozygous hybrids.

Cloning of superior coffee plants by somatic embryogenesis can assist breeding programs on reducing the cost and time for launch of new cultivars. This study aimed to evaluate the efficiency of this methodology for cloning coffee trees with high heterozygosity, and to gather evidence that clonal progenies are faithful copies of mother plants. Selected plants IAC1 and IAC 2 from Coffea arabica breeding populations, resistant to leaf rust and leaf miner, respectively, were cloned via indirect somatic embryogenesis. Expression of selected genes involved in biological processes potentially affected by in vitro cultivation was evaluated by quantitative analysis. Genes encoding proteins associated with maintenance of DNA integrity and control of cell cycle presented predictable expression patterns along the clonal multiplication process. There were differences in the expression pattern of genes linked to in vitro cultivation-related stress, which were observed comparing either IAC 1 and IAC2 genotypes or clones and their corresponding mother plant. Those analyses suggest that the somatic embryogenesis does not lead to major genomic instability and clones are identical copies of mother plants, even with detected differences in the expression of genes that influence the response of in vitro cultivation

CRISPR technology towards genome editing of the perennial and semi-perennial crops citrus, coffee and sugarcane.

Gene editing technologies have opened up the possibility of manipulating the genome of any organism in a predicted way. CRISPR technology is the most used genome editing tool and, in agriculture, it has allowed the expansion of possibilities in plant biotechnology, such as gene knockout or knock-in, transcriptional regulation, epigenetic modification, base editing, RNA editing, prime editing, and nucleic acid probing or detection. This technology mostly depends on in vitro tissue culture and genetic transformation/transfection protocols, which sometimes become the major challenges for its application in different crops. Agrobacterium-mediated transformation, biolistics, plasmid or RNP (ribonucleoprotein) transfection of protoplasts are some of the commonly used CRISPR delivery methods, but they depend on the genotype and target gene for efficient editing. The choice of the CRISPR system (Cas9, Cas12), CRISPR mechanism (plasmid or RNP) and transfection technique (Agrobacterium spp., PEG solution, lipofection) directly impacts the transformation efficiency and/or editing rate. Besides, CRISPR/Cas technology has made countries rethink regulatory frameworks concerning genetically modified organisms and flexibilize regulatory obstacles for edited plants. Here we present an overview of the state-of-the-art of CRISPR technology applied to three important crops worldwide (citrus, coffee and sugarcane), considering the biological, methodological, and regulatory aspects of its application. In addition, we provide perspectives on recently developed CRISPR tools and promising applications for each of these crops, thus highlighting the usefulness of gene editing to develop novel cultivars

Influence of allergen avoidance on the eosinophil phase of airway inflammation in children with allergic asthma

BACKGROUND: Exposure to relevant allergens causes an increase in bronchial hyperresponsiveness, as well as an inflammatory reaction at the site of the bronchial mucosa in patients with asthma. OBJECTIVE: The purpose of this study was to determine whether antigen avoidance can exert an antiinflammatory effect on the eosinophil phase of airway inflammation in children with asthma. METHODS: The level of bronchial hyperreactivity and the percentage of eosinophils in sputum samples obtained by inhalation of hypertonic saline solution, were evaluated in a group of asthmatic children allergic to house dust mite before and after a period of antigen avoidance in an Alpine environment (1756 m). RESULTS: At the end of the avoidance period PC20 increased from a median value (lower and upper quartile: Q1, Q3) of 1.17 (0.74, 4.75) to 3.5 (1.18, 8.87) mg/ml (p = 0.02), and eosinophil percentage in the sputum decreased from a median value (Q1, Q3) of 14.02 (3.34, 28.24) to 2.08 (0, 7.4) (p less than 0.01). CONCLUSION: A 3-month period of antigen avoidance can significantly reduce the eosinophil phase of airway inflammation, along with bronchial hyperresponsiveness, in patients with asthma

Effect of high altitude on bronchial hyperreactivity (BHR), Specific IgE (SSIgE) and basophil histamine releasability (HR) in asthmatic children

Study on the effect of high altitude on bronchial hyperreactivity (BHR), Specific IgE (SSIgE) and basophil histamine releasability (HR) in asthmatic childre

Risposta degli eosinofili in presenza-assenza di pneumoallergeni in bambini con asma allergica

Studio su risposta degli eosinofili in presenza-assenza di pneumoallergeni in bambini con asma allergic

Variation in inflammatory markers according to allergen exposure and climate

Study on the variation in inflammatory markers according to allergen exposure and climat