Crown-down preflaring in the determination of the first apical file

In this study, scanning electron microscopy (SEM) was used to evaluate the adaptation of the first apical file after preflaring in mesiobuccal (MB) and mesiolingual (ML) canals of mandibular molars considering the tactile sensibility as a reference. The mesial canals (n = 22) of human mandibular molar teeth were used, and the first instrument to bind to the working length was determined after preflaring and crown-down shaping. Digital images of the root apex were acquired and a single examiner determined the contact of the file with the walls using Image J software. The results showed that the file was in contact in 47.83% and 31.71% in the MB and ML canals, respectively. When the apexes are fused, the average was 40.03%. A descriptive analysis showed that the first apical file did not touch all dentin walls in any of the samples

Induction of systemic resistance to anthracnose in common bean by the avirulent delta race of Colletotrichum lindemuthianum

O objetivo deste trabalho foi avaliar o potencial da raça delta avirulenta do fungo Colletotrichum lindemuthianum, como protetora contra raças virulentas deste fungo e quanto à capacidade de induzir resistência sistêmica em feijoeiro-comum (Phaseolus vulgaris). Quatro cultivares de feijoeiro foram avaliadas quanto às alterações nas atividades de beta-1,3-glucanase e quitinase, em dois estádios de desenvolvimento (V2 e R6), três dias após a aplicação de suspensão de esporos de C. lindemuthianum raça delta avirulenta, em comparação com aplicações de água e ácido salicílico. As plantas foram, então, infectadas com o patótipo virulento 33/95 de C. lindemuthianum em suspensão e, depois de cinco dias, foram reavaliadas quanto à atividade das enzimas. Observaram-se acréscimos significativos nas atividades da beta-1,3-glucanase e quitinase, após inoculação do fungo indutivo, nas duas avaliações, nos dois estádios de desenvolvimento. As atividades da beta-1,3-glucanase e da quitinase variaram entre as cultivares e entre os estádios de desenvolvimento das plantas. A correlação entre o índice de severidade da doença e a atividade das enzimas foi altamente significativa. O uso de C. lindemuthianum raça delta avirulenta diminuiu a severidade da doença e pode ter potencial para controlar a antracnose do feijoeiro.The objectives of this work were to evaluate the potential of the avirulent delta race of Colletotrichum lindemuthianum as a protector against virulent races of this fungus and induce systemic resistance to anthracnose in common bean (Phaseolus vulgaris). Four common bean cultivars were evaluated for changes in the activities of beta-1,3-glucanase and chitinase at two common bean developmental stages, V2 and R6, three days after the infection with delta race of C. lindemuthianum, in comparison with control applications of water and salicylic acid. The plants were then infected with a spore suspension of 33/95, a virulent C. lindemuthianum patotype and reevaluated five days later for the enzyme activities. Significant increases in the activities of both beta-1,3-glucanase and chitinase were observed after inoculation of inductive fungus at the two evaluation periods, at both plant development stages. The activities of both beta-1,3-glucanase and chitinase varied among cultivars and among plant development stages. A significant correlation was observed between the disease severity and the enzyme activity. The avirulent delta race of C. lindemuthianum reduced the severity of anthracnose on common bean and may have the potential to control the disease

Heated water and UV-C radiation to postharvest control of Cryptosporiopsis perennans on apples

O objetivo deste trabalho foi avaliar a colonização de Cryptosporiopsis perennans na epiderme de maçãs e a eficiência da aplicação de água aquecida e radiação UV-C no controle desse patógeno. Em maçãs submetidas à inoculação de C. perennans, a colonização de lenticelas e das áreas adjacentes pelo patógeno foi avaliada por microscopia eletrônica de varredura. A sensibilidade dos conídios de C. perennans aos tratamentos foi avaliada em suspensão aquosa, às temperaturas de 28, 45, 50 e 55°C, por 15 e 30 s, e às doses de radiação UV-C de 0,018, 0,037, 0,075, 0,150, 0,375, 0,750, 1,500 e 3,000 kJ m-2. Em maçãs submetidas à inoculação de C. perennans, foram avaliados os efeitos de 0,375, 0,750 e 1,500 kJ m-2 de radiação UV-C e da aspersão de água aquecida à 50°C, por 15 e 30 s no controle do patógeno. O fungo produziu abundante micélio e conídios nas lenticelas e nas áreas adjacentes, na epiderme das maçãs. A água aquecida a 50°C por 15 s e à dose de radiação de UV-C de 0,750 kJ m-2 reduzem em mais de 99% a sobrevivência de conídios. A aspersão de água aquecida a 50°C por 15 s e à dose de radiação de UV-C de 0,375 kJ m-2, controlam C. perennans em maçãs.The objective of this work was to assess the colonization of Cryptosporiopsis perennans in the epidermis of apples and the efficiency of heated water and UV-C radiation application to control this pathogen. In apples inoculated with C. perennans, the colonization of lenticels and adjacent areas by the pathogen was observed by electronic scanning microscopy. The sensitivity of C. perennans conidia was evaluated in aqueous suspension, at temperatures of 28, 45, 50 and 55°C for 15 and 30 s, and at UV-C radiation doses of 0.018, 0.037, 0.075, 0.150, 0.375, 0.750, 1.500 and 3.000 kJ m-2. The effects of UV-C radiation doses at 0.375, 0.750 and 1.500 kJ m-2 and heated water at 50°C, sprayed during 15 and 30 s were evaluated for controlling C. perennans in apples inoculated with the pathogen. The fungus produced abundant mycelium and conidia in lenticels and adjacent areas on the epidermis of the apples. The heated water at 50°C during 15 s and a 0.750 kJ m-2 UV-C radiation dose reduced conidia survival in more than 99%. Heated water sprayed at 50°C during 15 s and a UV-C radiation dose of 0.375 kJ m-2 control C. perennans in apples

Morphology of Larval Gordius dimorphus (Nematomorpha: Gordiida)

Scanning electron microscopy was used to analyze superficial features of Gordius dimorphus Poinar, 1991, larvae that might serve as generic or specific diagnostic characters. Three adults of G. dimorphus (2 males and 1 female) were maintained under laboratory conditions until oviposition, which occurred within long strings commonly referred to as egg strings. Larvae have a cylindrical body, annulated and divided into 2 sections, plus an anterior preseptum and a posterior postseptum. Three concentric rings with 6 spines each surround the proboscis. The proboscis is retractile, dorsoventrally flattened, with 1 pair of forceps-like projections on its distal-most portion. On the surface of each projection, 3 pairs of aculeiforms spines are aligned and lean toward the proboscis opening. One large spine is present on the posterior portion of the postseptum. Papillae were not observed. Gordius dimorphus larvae are similar to previous light microscope descriptions. This is the first record of G. dimorphus in Brazil