Silvia A. Lourenço

Immunohistochemical and in situ hybridization studies of the liver and kidney in human leptospirosis

An in situ hybridization (ISH) assay for the detection of leptospiral DNA in tissues was described and its diagnostic and pathogenetic usefulness in combination with immunohistochemistry (IHC) was evaluated in formalin-fixed, paraffin-embedded liver and kidney samples from human fatal cases of leptospirosis. IHC assays with anti-E-cadherin antibodies assessed the liver-plate disarray frequently observed in leptospirosis. Immunohistochemistry detected leptospiral antigen (LAg) in macrophages, both in human liver and kidney. In guinea pigs, in addition to these findings, staining on cell membranes of hepatocytes and, occasionally, in apical membrane of kidney tubular cells was demonstrated. Positive ISH signal was observed chiefly in the nuclei of human hepatocytes and in the cytoplasm and nuclei of liver cells of experimentally infected guinea pigs. Loss of E-cadherin membrane expression is associated with liver-plate disarray. These findings were discussed in the contention that, in leptospirosis, cell membrane damage might be important for the pathogenesis of the disease. Finally, it was suggested that both IHC and/or ISH might be used for both diagnostic and research purposes.

Incidência de danos pós-colheita em goiabas no mercado atacadista de São Paulo e sua relação com a prática de ensacamento dos frutos

The incidence of post harvest damages in guavas was quantified from April 2005 to August 2006 in four wholesalers from the terminal wholesale market of Sao Paulo (CEAGESP). The sampling was stratified by fruit size, fruit origin, flesh color and bagging the fruit. All fruit from 323 guava boxes were visually assessed. Post harvest mechanical injuries and diseases were quantified. Five thousand and eighty one fruit were assessed, 51.1% of which came from orchards where fruit received paper bags some time before harvesting. Post harvest mechanical injuries were observed in 63% of fruit but only 5.5% of fruit showed symptoms of post harvest diseases. These diseases incidence was correlated to the incidence of post harvest mechanical injuries only in bagged fruit (R=0.20, p< 0.05). These variables were not correlated in fruit not bagged (R=0.09). Black spot (Guignardia psidii) was observed in 3.5 % of fruit and anthracnose (Colletotrichum spp.), in 1.1 % of them. Post harvest rots caused by fungi from genera Fusicoccum, Rhizopus, and Pestalotia occurred in less than 1 % of fruit. The incidence of post harvest diseases caused by quiescent pathogens was significantly greater in bagged fruit (7.7 % of fruit) than in non-bagged fruit (2.1 % of fruit). The opposite was observed for wound-pathogens, with averages of 0.3 % and 0.8 % of symptomatic guavas for bagged and non-bagged fruit, respectively. There was no significant difference in the incidence of quiescent diseases in bagged fruit from varieties with white flesh (7.8 %) or red flesh (7.3 %).

Quantificação de danos pós-colheita em pêssegos no mercado atacadista de São Paulo

A ocorrencia de disturbios pos-colheita em pessegos (Prunus persicae) e considerada uma importante causa de desvalorizacao do produto por ocasiao da comercializacao. Este trabalho teve por objetivo quantificar e caracterizar os danos pos-colheita em pessegos na CEAGESP, o maior entreposto atacadista do Estado de Sao Paulo. Foram realizados levantamentos da incidencia de danos em 1% dos frutos comercializados na CEAGESP, em cada data de avaliacao, nos periodos de outubro de 2001 a janeiro de 2002 e de outubro de 2002 a janeiro de 2003. A amostragem foi estratificada por variedade de pessego. Todos os frutos da amostra foram avaliados na propria CEAGESP, onde foram quantificados os danos bioticos e abioticos. Frutos com inicio de podridoes, sem a ocorrencia de sinais dos patogenos, foram incubados por 48 h em câmara umida, periodo apos o qual procedeu-se a identificacao do agente causal. Foram amostrados em media 1.835 frutos por avaliacao. Os danos pos-colheita variaram de 4,9 a 44,5% dos frutos amostrados. Danos provocados por fungos variaram de 2,4 a 15,2%. Foram constatados fungos dos generos Rhizopus, Monilinia, Geotrichum, Cladosporium, Fusarium e Alternaria, alem de bacterias e de fungos leveduriformes. Esses ultimos foram constatados em todas as datas de amostragem em uma representativa fracao (ate 46%) dos frutos que apresentavam podridoes associadas a ferimentos. Nao foi constatada diferenca na suscetibilidade das variedades mais comercializadas. Nao houve diferenca no nivel de danos nos frutos comercializados em diferentes embalagens. O nivel de dano esteve relacionado unicamente a procedencia do fruto.

Efeito de sanificantes no controle pós-colheita da podridão parda (Monilinia fructicola) e da podridão mole (Rhizopus stolonifer) em pêssegos

ABSTRACT O objetivo desse trabalho foi avaliar o efeito in vitro e in vivo dossanificantes cloreto de benzalconio (Fegatex ® ), biomassa citrica(Ecolife 40® ) e ozonio no controle da podridao parda ( Moniliniafructicola ) e da podridao mole ( Rhizopus stolonifer ) em pessegos dascultivares Aurora, Dourado e Flor da Prince. Cloreto de benzalconioe biomassa citrica, aplicados in vitro, ambos na concentracao de1000 µL L -1 , inibiram totalmente o crescimento radial (micelial)de M. fructicola , porem nenhum deles foi eficiente no controle de R. stolonifer . Cloreto de benzalconio aplicado de forma preventiva, Abreu, F. M., Lourenco, S. A., Bassetto, E., Goncalves, F. P., Martins, M. C., Amorim, L. Efeito de sanificantes no controle pos-colheita dapodridao parda ( Monilinia fructicola ) e da podridao mole ( Rhizopus stolonifer ) em pessegos. Summa Phytopathologica , v.34, n.1, p.86-88, 2008 RESUMO na concentracao de 3000 µL L -1 , reduziu a podridao parda emfrutos inoculados sem ferimentos. Quando aplicado de formacurativa em frutos nao feridos esse produto foi eficiente em todasas concentracoes testadas. Nenhum produto aplicado nos frutosde forma curativa foi eficiente no controle da podridao parda,quando a inoculacao do fungo foi realizada atraves de ferimentos.Nenhum dos produtos foi eficiente no controle da podridao mole. Oozonio (0,1 µL L

Efeito da irradiação UV-C no controle da podridão parda (Monilinia fructicola) e da podridão mole (Rhizopus stolonifer) em pós-colheita de pêssegos

The purpose of this work was to evaluate the effect of UV-C irradiation in vitro to control M. fructicola and R. stolonifer and the diseases caused by them in peach fruits. Mycelial growth was evaluated after exposure of the pathogens on PDA medium to different UV-C irradiation concentrations of 0, 0.26, 0.52, 1.04, 3.13, 5.22, 10.44, 15.66 and 31.32 kJ.m-2. The UV cabinet was equipped with four lamps with the fluency rate of 1.74 mW.cm-2. Peach fruits were treated with UV-C irradiation in a protective and curative way. In the protector treatment, fruits were exposed to 1.04 kJ.m-2 for 1 min. and were inoculated immediately and after 16, 24 and 40 hours. In the curative treatment, peach fruits were inoculated, incubated and irradiated with 0, 1.04, 5.22, 10.44, 15.66 and 31.32 kJ.m-2 UV-C concentrations. Disease incidence and severity of brown rot were evaluated. In vitro, only the concentrations applied during 1 and 10 min. of exposure reduced the mycelial growth of M. fructicola, while the application of UV-C for 10-15 minutes reduced the mycelial growth of R. stolonifer and the concentration applied for 30 minutes completely inhibited the mycelial growth of this pathogen. There was no effect caused by UV-C light in the protective control, or by UV-C light in the curative control of brown rot. The irradiation of fruits with UV-C was effective in the curative control of soft rot, and the best results were observed with an exposure time of 10 minutes.

Expression of laminin-5 and integrins in actinic cheilitis and superficially invasive squamous cell carcinomas of the lip

The progression of carcinogenesis entails the detachment of cells, invasion and migration of neoplastic cells. Alterations in epithelial adhesion and basement membrane proteins might mediate the early stages of carcinogenesis. This study investigated the expression of adhesion molecules and the basement membrane protein laminin-5 in actinic cheilitis (AC) and incipient squamous cell carcinoma of the lower lip to understand early photocarcinogenesis. Ln-5γ2 chain as well as α3, β1 subunits of α3β1 heterodimer and β4 subunit of integrin α6β4 were evaluated by immunohistochemistry in 16 cases of AC and 16 cases of superficially invasive squamous cell carcinoma (SISCC). Most AC cases showed reduced expression of β1, β4 and α3 integrins, and SISCCs lacked β1, β4 and α3 integrins in the invasive front. AC cases were negative for the Ln-5γ2 chain. Five cases of SISCC (31%) showed heterogeneous Ln-5γ2 chain expression in the invasive front of the tumor. Integrin β1, β4 and α3 expression is lost during the early stages of lip carcinogenesis. Expression of Ln-5γ2 in the invasive front in cases and its correlation with tumor progression suggest that it mediates the acquisition of the migrating and invading epithelial cell phenotype.

Eradicant and curative treatments of hexanal against peach brown rot

Brown rot, caused by Monilinia spp. , is one of the most important peach (Prunuspersica (L.) Batsch) diseases and the main cause of postharvest losses. Currently, alternative methods for postharvest disease control, such as the use of volatiles, are under investigation. The objective of this study was to determine the effects of hexanal on the in vitro development of Monilinia fructicola and M. laxa and on monocyclic components of brown rot on peaches. To evaluate the effect on pathogen development in vitro, a single dose of 215 µL of liquid hexanal was placed on glass jars in closed plastic containers (4.3 L) at the moment of fungi transfer, 24 or 48 h after transferring to Petri dishes. After hexanal application, the Petri dishes were kept inside the containers that were closed for 24 h at 20 oC. Mycelial growth was measured seven days after hexanal removal. For in vivo assays, inoculated fruits were kept in closed plastic containers, and hexanal was applied at the moment of fruit inoculation or 24 hours thereafter. The monocyclic components infection frequency, expressed as brown rot incidence, lesion diameter and lesion sporulation, were assessed daily for seven days. Overall, hexanal was more effective in inhibiting mycelial growth when applied at the moment of pathogen transfer. Hexanal did not prevent pathogen infection, but reduced lesion diameter and completely inhibited spore production on the fruit for both treatments. Hexanal provides a promising alternative for chemical control and can be used in postharvest handling systems.

Honeybees can spread Colletotrichum acutatum and C. gloeosporioides among citrus plants

Postbloom fruit drop (PDF) is an important citrus disease that causes up to 100% yield losses during years in which conditions are favourable for the occurrence of epidemics. The conidia of Colletotrichum acutatum and C. gloeosporioides, causal agents of PFD, are predominantly dispersed by rain splash. At the beginning of epidemics, the distribution of diseased plants is random and the disease progress rate is very high, which is unusual for pathogens spread by rain splash. As the pathogen produces abundant conidia on diseased petals, pollinating insects may contribute to disease dispersal. This study investigated honeybees (Apis mellifera) as dispersal agents of C. acutatum and C. gloeosporioides among citrus plants. Two experiments were carried out in a screenhouse in which citrus plants were protected (or not) in insect-proof cages. The source of inoculum was placed on one side of the screenhouse, and a honeybee hive was placed on the opposite side. All uncaged plants showed symptoms of the disease, and none of the caged plants exhibited PFD symptoms. The monomolecular model showed a good fit to disease progress in both experiments. Conidium-like structures of Colletotrichum spp. were identified attached to the bodies of the honeybees by scanning electron microscopy. These results have revealed that honeybees disperse Colletotrichum among citrus plants. This article is protected by copyright. All rights reserved.

Actinic prurigo cheilitis: A clinicopathologic review of 75 cases

Abstract:Actinic prurigo (AP) is a chronic idiopathic photodermatosis that primarily affects American Indians in the United States and Mestizos in Latin American countries. Clinically, the onset of the disease is usually in the first decade of life but may appear initially in adult life, and it is characterized by symmetric involvement of sun-exposed areas of the skin, particularly areas of the face, resulting in polymorphic erythematous papules, macules, and plaques in different stages of evolution. Lower lip involvement includes swelling, scaling, fissures, hyperpigmentation, and ulcerations of the vermilion border. and in some cases could represent the only manifestation of the disease. The histopathologic features of AP have been studied; however, there is a controversy regarding whether AP cheilitis has distinct histopathologic features that could allow accurate separation from other specific and nonspecific forms of cheilitis. The diagnosis can be challenging, mainly when lip lesions are the only manifestation of the disease. In this study, the authors investigate the clinicopathologic features of 75 cases of AP cheilitis to provide further criteria for its diagnosis and classification. All 75 patients presented with lip lesions. Thirty-three cases were diagnosed as AP cheilitis with cutaneous lesions and 42 cases were diagnosed as AP cheilitis without cutaneous lesions (only lip lesions). Histologically, of the 33 cases with AP cheilitis with cutaneous lesions, 17 (52%) cases showed follicular cheilitis, and of the 42 cases that had only lip lesions, 18 (43%) cases showed follicular cheilitis. Histologically, AP cheilitis can present as follicular cheilitis; thus, supporting the diagnosis. Also, our findings confirm that lip lesions can present as the only manifestation of the disease, showing typical histological and clinical features. This form of cheilitis has not being well described in the dermatologic and dermatopathologic literature.

Occurrence of Phytophthora parasitica in peace lily in Brazil

Occurrence of Phytophthora parasitica in peace lily in Brazil The occurrence of root and crown rot of Spathiphyllum wallisi caused by Phytophthora parasitica is reported for the first time in the State of Sao Paulo, Brazil. A planta Spathiphyllum wallisi Regel, conhecida como lirio da paz, e muito usada na decoracao de interiores, se adaptando bem em locais sombreados. Em fevereiro de 2003, amostras de lirio da paz, procedentes de estufas de producao, localizadas no municipio de Cordeiropolis, SP, com necrose do bulbo e consequente amarelecimento das folhas baixeiras e murcha das plantas (Figura 1) foram encaminhadas para analise na Clinica Fitopatologica da ESALQ/USP. Procedeuse estudos de diagnose e testes de patogenicidade em mudas sadias, com o objetivo de se identificar o agente causal. Fragmentos de bulbos lesionados, previamente desinfestados em alcool 70%, foram plaqueados em meio de cultura agaragua, seguido da repicagem para batata-dextrose-agar (BDA). As placas foram armazenadas em condicoes ambientais de laboratorio sob luminosidade continua. O isolado obtido apresentou aspecto cotonoso em cultura, micelio cenocitico, esporangioforos e esporângios limoniliformes. O teste de patogenicidade foi realizado atraves da inoculacao de 100 ml de uma suspensao de esporos (10 zoosporos/ml) sobre o colo de plantas sadias de lirio da paz, de dois meses de idade. As plantas foram mantidas em casa de vegetacao em condicoes de temperatura ambiente (26 °C ± 3 °C). Para a testemunha utilizou-se apenas agua. Com base em analises morfologicas e fisiologicas, o isolado foi identificado como Phytophthora parasitica J. F. Dastur (Ho, H.H. Mycologia 73:705-714, 1981), apresentando esporângios limoniformes, papilados (Figura 2) e nao caducos. Houve crescimento micelial em meio de cultura BDA, a 37 °C, e uma maior formacao de esporângios quando as culturas foram mantidas em agua. A reproducao dos sintomas de P. parasitica em S. wallisi foi confirmada apos seis dias da inoculacao. Observou-se necrose da haste, seguida de murcha e morte das plantas. O patogeno foi reisolado dos tecidos infetados, comprovando sua patogenicidade. Este e o primeiro relato da ocorrencia de P. parasitica afetando lirio da paz no Brasil. FIG. 1 Sintomas causados por Phytophthora parasitica em planta de lirio da paz Spathiphyllum