Atividade antifúngica e potencial antibiofiome do extrato hidroetanólico de Spondias mombin L. e de suas frações frente a leveduras do gênero Candida / Antifungal activity and antibiofiome potential of the hydroethanolic extract of Spondias mombin L. and its fractions against yeasts of the genus Candida

A Candidose é uma patologia que pode ter manifestações locais e também sistêmicas e acontece pela proliferação de fungos do gênero Candida. O tratamento desta patologia é realizado com antifúngicos mas, devido a resistência dos fungos causadores desta enfermidade se faz necessário conhecer outros antifúngicos. A ação antimicrobiana do extrato hidroetanólico de Spondias mombin L. já é conhecida e é fundamental que seja pesquisado a atividade antibiofilme das substâncias, uma vez que estes fungos causam adoecimento quando se acumulam e proliferam. Sabendo disso é que o presente estudo teve por objetivo principal investigar a ação antifúngica e antibiofilme do extrato hidroetanólico (EH) de Spondias mombin L. e das frações de taninos, flavonoides e ácidos fenólicos, frente a fungos do gênero Candida, de importância clínica. Para isto, determinou-se a concentração inibitória mínima por meio do uso de discos e pela técnica da microdiluição em caldo, concentração inibitória mínima de aderência, determinação da curva de morte dos fungos e atividade antibiofilme das frações de ácidos fenólicos, flavonoides e tanino, frente aos fungos Candida albicans, Candida tropicalis, Candida Krusei e Candida Glabrata, utilizando como controle positivo a Nistatina (100.000 UI), em triplicata. Foi visto que, a atividade antifúngica e antibiofilme do EH e de suas frações analisadas existe, porém, quando comparamos as frações com o EH este último apresentou melhor atividade em suas maiores concentrações (500 µg/mL e 250 µg/mL) e quando traçamos o comparativo entre a ação antifúngica e antibiofilme das substâncias testadas e do grupo controle, tivemos melhores resultados do grupo controle frente aos fungos testados. Desta forma foi possível concluir que o extrato hidroetanólico apresentam resultados superiores de atividade antifúngica frente a todos os microrganismos testados, exceto C. krusei e antibiofilme frente a, pelo menos, uma das espécies de Candida e que este extrato teve resultados muito semelhantes e, por vezes, superior ao grupo controle (AU).

Candidosis is a pathology that can have local as well as systemic manifestations and happens due to the proliferation of fungi of the Candida genus. The treatment of this pathology is carried out with antifungal agents, but due to the resistance of the fungi that cause this disease, it is necessary to know other antifungal agents. The antimicrobial action of the hydroethanolic extract of Spondias mombin L. is already known and it is essential that the antibiofilm activity of the substances be researched, since these fungi cause illness when they accumulate and proliferate. Knowing that, this study aimed to investigate the antifungal and antibiofilm action of the hydroethanolic extract (EH) of Spondias mombin L. and its fractions, against fungi of the genus Candida, of clinical importance. For this, the minimum inhibitory concentration was determined through the use of disks and the technique of microdilution in broth, minimum inhibitory concentration of adhesion, determination of the fungal death curve and antibiofilm activity of the fractions of phenolic acids, flavonoids and tannin, against the fungi Candida albicans, Candida tropicalis, Candida Krusei and Candida Glabrata, using nystatin (100,000 IU) as a positive control, in triplicate. It was seen that the antifungal and antibiofilm activity of EH and its analyzed fractions exists, however, when we compare the fractions with EH, the latter showed better activity at its highest concentrations (500 µg/mL e 250 µg/mL) and when we draw the comparison between the antifungal and antibiofilm action of the tested substances and the control group, we had better results than the control group against the tested fungi. Thus, it was possible to conclude that the hydroethanolic extract presented superior results of antifungal activity against all tested microorganisms, except C. krusei and antibiofilm against at least one of the Candida species and that this extract had very similar results and, for times higher than the control group (AU).

Three new species of Gliocephalotrichum causing fruit rot on different hosts from Brazil.

The genus Gliocephalotrichum (Nectriaceae), originally described as a soil-borne fungus, has been associated with postharvest diseases, especially of tropical fruits. Taxonomic studies using both morphological and molecular phylogenetic analyses have contributed to recognition of novel species in several countries. However, in Brazil, only three isolates of Gliocephalotrichum have been collected from soil samples and roots since the late 1970s. Our study expands the sample range using many Gliocephalotrichum isolates obtained from rotting fruits of tropical plant species in different states of Brazil. Polyphasic taxonomy was assessed with phylogenetic analyses of DNA sequences from four nuclear loci, morphological comparisons, and pathogenicity tests. As a result, three known species (G. bulbilium, G. longibrachium, and G. simplex) were identified from new hosts and locations in Brazil. In addition, three new species are described-G. abrachium, G. brasiliense, and G. caryocaris. A key to all Gliocephalotrichum species worldwide is provided. Although species of Gliocephalotrichum have not been considered to be important plant pathogens, this study shows they may cause postharvest fruit rot in tropical fruits and therefore have an impact in communities that depend economically on the harvest and sale of these fruits.

Convergent and distinctive functions of transcription factors VdYap1, VdAtf1, and VdSkn7 in the regulation of nitrosative stress resistance, microsclerotia formation, and virulence in Verticillium dahliae.

Reactive oxygen/nitrogen species (ROS/RNS) play a fundamental role in plant-fungal interactions. How pathogenic fungi manipulate plant-derived ROS/RNS is of importance to the outcomes of these interactions. In this study, we explored the individual and combined contributions of three transcription factors, VdAtf1, VdYap1, and VdSkn7, in the response to ROS/RNS, microsclerotia formation, and virulence in the plant wilt pathogen Verticillium dahliae. We showed that VdYap1 is essential for ROS response. Additionally, mutants lacking any combination of the three genes shared significant hypersensitivity to nitro-oxidative stress like sodium nitroprusside dehydrate and double deletions lacking VdYap1 and VdAtf1 resulted in further increased sensitivity to ROS. Double deletion of VdAtf1 and VdSkn7 reduced melanin production and virulence while simultaneous lack of VdSkn7 and VdYap1 disrupted nitrogen metabolism and ROS resistance. Finally, comparison of transcriptional profiles of the respective single or double mutants in response to nitro-oxidative stress revealed that the three transcription factors are involved in denitrification of nitrated alkanes and lipids to protect against nitro-oxidative stress. Taken together, our results demonstrate convergent and distinctive functions of VdYap1, VdAtf1, and VdSkn7 in V. dahliae, and provide new data on their roles in response to ROS/RNS in fungi.

Yellow mombin and jackfruit seeds residues applied in the production of reducing sugars by a crude multi-enzymatic extract produced by Penicillium roqueforti ATCC 101110.

BACKGROUND: As an alternative to the use of widely investigated agro-industrial residues, the present study aimed to promote the valorization of two selected residues, yellow mombin seed (YS) and jackfruit seed (JS), as a result of their enhanced performance. RESULTS: YS was applied as a solid state substrate for Penicillium roqueforti ATCC 101110 cultivation (25 °C, Aw = 0.963, 107 spores g-1 and 142 h) to produce a crude multi-enzymatic extract (CE-YS) containing activities of CMCase = 31.95 U g-1 , xylanase = 56.85 U g-1 , exoglucanase = 5.55 U g-1 and FPase = 24.60 U g-1 . CE-YS was then applied to six different residues saccharification and the best performance was obtained with jackfruit seed residue (JS), which was selected for enzymatic saccharification. The highest productivity of reducing sugars expressed as glucose (6.26 mg g-1 h-1 ) was obtained under the conditions: 40.7 g L-1 JS, 5 mmol L-1 MgCl2 , 65 °C, 120 rpm, pH 3.0 (citrate buffer 50 mmol L-1 ) and 18 h. CONCLUSION: The residues, YS and JS, can be used satisfactorily for the production of bioproducts of great industrial applicability, such as crude extracts (containing cellulolytic enzymes) and RS (which can be converted, for example, into bioethanol). © 2020 Society of Chemical Industry.

Muscodor brasiliensis sp. nov. produces volatile organic compounds with activity against Penicillium digitatum.

Endophytic fungi belonging to Muscodor genus are considered as promising alternatives to be used in biological control due to the production of volatile organic compounds (VOCs). The strains LGMF1255 and LGMF1256 were isolated from the medicinal plant Schinus terebinthifolius and, by morphological data and phylogenetic analysis, identified as belonging to Muscodor genus. Phylogenetic analysis suggests that strain LGMF1256 is a new species, which is herein introduced as Muscodor brasiliensis sp. nov. The analysis of VOCs production revealed that compounds phenylethyl alcohol, α-curcumene, and E (ß) farnesene until now has been reported only from M. brasiliensis, data that supports the classification of strain LGMF1256 as a new species. M. brasiliensis completely inhibited the phytopathogen P. digitatum in vitro. We also evaluated the ability of VOCs from LGMF1256 to inhibit the development of green mold symptoms by inoculation of P. digitatum in detached oranges. M. brasiliensis reduced the severity of diseases in 77%, and showed potential to be used for fruits storage and transportation to prevent the green mold symptoms development, eventually reducing the use of fungicides.

Can arbuscular mycorrhizal fungi from non-invaded montane ecosystems facilitate the growth of alien trees?

It is generally assumed that recruitment and expansion of alien species along elevation gradients are constrained by climate. But, if plants are not fully constrained by climate, their expansion could be facilitated or hindered by other factors such as biotic interactions. Here, we assessed the composition of arbuscular mycorrhizal fungi (AMF) in soils along an elevation gradient (i.e. 900 m, 1600 m, 2200 m and 2700 m a.s.l.) through a fungal DNA meta-barcoding approach. In addition, we studied in the greenhouse the effects of AMF on growth and phosphorous (P) nutrition of seedlings of the alien trees Gleditsia triacanthos, Ligustrum lucidum and Pyracantha angustifolia cultivated in soils from those elevations, spanning the elevation at which they already form monospecific stands (below 1450 m a.s.l.) and higher elevations, above their current range of distribution in montane ecosystems of Central Argentina. For comparison, we also included in the experiment the dominant native tree Lithraea molleoides that historically occurs below 1300 m a.s.l. Arbuscular mycorrhizal fungal community composition showed strong community turnover with increasing elevation. The effects of these AMF communities on plant growth and nutrition differed among native and alien trees. While P nutrition in alien species' seedlings was generally enhanced by AMF along the whole gradient, the native species benefited only from AMF that occur in soils from the elevation corresponding to its current altitudinal range of distribution. These results suggest that AMF might foster upper range expansion of these invasive trees over non-invaded higher elevations.

Efeito do extrato da folha de spondias mombin sobre a superfície de dentes humanos - um estudo in vitro / Effect of mombin spondias leaf extract on the surface of human teeth - an in vitro study

INTRODUÇÃO: O estudo da fitoterapia na prevenção e no tratamento de doenças tem estimulado pesquisas com plantas medicinais na Odontologia. Dentre essas plantas destaca-se a espécie Spondias mombin por apresentar disponibilidade de matéria-prima e amplo espectro de ações farmacológicas que incluem atividades antimicrobiana, anti-inflamatória, cicatrizante e antioxidante. OBJETIVO: Investigar o efeito do extrato de Spondias mombin L. (cajá) sobre a superfície de dentes humanos. METODOLOGIA: O extrato de cajá foi preparado em sua diluição 1:32=31,25 mg/ml. Trinta dentes humanos foram seccionados (6,0 x 6,0 mm) preservando as proximais. Os fragmentos foram divididos aleatoriamente em 3 grupos (n=10 por grupo) de acordo com os grupos: extrato hidroetanólico de S. mombin L., Digluconato de clorexidina 0,12% e água destilada. Cada fragmento foi imerso nas respectivas substâncias por 1 minuto, 2 vezes ao dia, durante 14 dias. Antes e após a imersão nas soluções, foram realizadas análises de cor, molhabilidade, rugosidade (Ra) e morfologia. O pH das substâncias também foi investigado. Os dados foram analisados estatisticamente por meio de ANOVA (1 e 2 fatores) e teste de Tukey para múltiplas comparações. RESULTADOS: Não houve diferença estatisticamente significativa em relação a cor entre os grupos. O extrato de cajá e clorexidina 0,12% apresentaram diferenças significativas (p<0,001), enquanto água destilada não apresentou diferenças estatísticas (p>0,005). Quanto a molhabilidade, não houve diferença estatisticamente significativa entre extrato de cajá (p>0,005), clorexidina 0,12% (p>0,005) e água destilada (p>0,005). Para rugosidade, não houve diferença estatisticamente significante entre as substâncias analisadas (p>0,0005). Além disso, não houve diferença estatística entre as substâncias e o tempo de imersão (p <0,0001). O pH médio do extrato hidroetanólico de cajá e clorexidina 0,12% was de 2,95 e 6,5, respectivamente. CONCLUSÃO: O pH do extrato de S.mombin L. é ácido e da clorexidina é neutro. A molhabilidade do extrato hidroetanólico de cajá foi bom tanto quanto a clorexidina. A cor dos fragmentos dentários foi alterada após o protocolo de imersão no extrato hidroetanólico de cajá e clorexidina 0,12%. A rugosidade dos fragmentos dentários analisados se manteve inalterada após o protocolo de imersão nas diferentes soluções testadas. O exame de microscopia eletrônica de varredura mostrou que não houve diferença na superfície do esmalte entre as soluções testadas (AU).

INTRODUCTION: The study of phytotherapy in the prevention and treatment of diseases stimulated the research with medicinal plants in Dentistry. Among these plants, the species Spondia mombin stands out for the availability of raw material and a broad spectrum of pharmacological actions that include antimicrobial, anti-inflammatory, cicatrizant and antioxidant activities. OBJECTIVE: To investigate tooth surface changes regarding cajá (Spondias mombin L.) extract. METHOD: The cashew extract was prepared in its dilution1:16=31,25 mg/ml. Thirty human teeth were sectioned (6.0 x 6.0 mm) preserving the proximal surfaces. Dental fragments were randomly divided into 3 groups (n =10 per group) according to the substances: hydroethanolic extract (31,25 mg/ml), 0.12% chlorhexidine and distilled water. Each fragment was immersed in the respective substance for 1 minute, twice daily for 14 days. Before and after the immersion, color analysis, wettability, roughness (Ra) and morphology as well as the pH levels of the substances were investigated. Data were analyzed statistically by means of ANOVA (one and two factors) and Tukey test for multiple comparisons. RESULTS: There was a statistically significant difference between color in the groups. Cajá extract and 0.12% chlorhexidine presented significant differences (p <0.001), while distilled water showed no statistical differences (p> 0.005). Regarding wettability, there was no statistically significant difference between Cajá extract (p>0.005), 0.12% chlorhexidine, and distilled water (p>0.005). For roughnes, there was no statistically significant difference between the analyzed substances (p>0.0005). In addition, there was no statistically significant difference between the substances and immersion time (p <0.0001). The mean pH of the hydroethanolic extract of cajá and 0.12% chlorhexidine is 2.95 and 6.5, respectively. CONCLUSION: pH of the extract of S.mombin L. is acid of the chlorhexidine is neutral. The wettability of the hydroethanolic extract of cajá was as good as 0.12% chlorhexidine. Color changes were observed after the immersion in hydroethanolic extract of cajá and 0.12% chlorhexidine. Roughness of the analyzed dental fragments remained unchanged after the immersion protocols. Scanning electron microscopy showed no difference in the enamel surface between the solutions tested (AU).

Antibacterial activity of Aroeira honeys produced in Minas-Gerais against bacteria of clinical importance / Atividade antibacteriana de méis de Aroeira produzidos em Minas-Gerais frente a bactérias de importância clínica

The biological activity of honey has been the subject of great scientific investigation. Bee products are widely used in folk medicine to treat human diseases due to their antibacterial and inhibitory potential action on different human pathogens. Ten honey samples produced by Apis mellifera in the northern of Minas Gerais state were tested against pathogenic microorganisms Staphylococcus aureus TSST (clinical isolated) and enterohaemorrhagic Escherichia coli ATCC 43895 for determination of their minimum inhibitory concentrations. The microdilution technique in broth Mueller-Hinton broth (MHB) was used in four concentrations (25, 12.5, 6.25 and 3.125%). There was a reduction of bacterial growth for the two target species at all concentrations tested. The optimal concentration for inhibition of S. aureus and E. coli were 3.125% (w/v). Therefore, the antibacterial activity of the tested samples evidences the potential of Aroeira honey produced in the north of Minas Gerais for therapeutic use, thus contributing to the aggregation value and commercialization of this type of honey.

A atividade biológica do mel tem sido objeto de relevante investigação científica. Produtos apícolas são amplamente utilizados na medicina popular para tratar doenças humanas por causa de sua potencial ação antibacteriana e inibitória a diferentes patógenos humanos. Dez amostras de mel produzidas por Apis mellifera, no norte do Estado de Minas Gerais, foram testadas contra os micro-organismos patogênicos Staphylococcus aureus TSST (isolado clínico) e Escherichia coli enterohemorrágica ATCC 43895 para determinação de suas concentrações inibitórias mínimas. A técnica de microdiluição em caldo Mueller-Hinton (CMH) foi utilizada em quatro concentrações (25, 12,5, 6,25 e 3,125%). Houve uma redução do crescimento bacteriano para as duas espécies alvo em todas as concentrações testadas. A concentração ótima para a inibição de S. aureus e E. coli foi de 3,125% (p/v). Portanto, a atividade antibacteriana das amostras testadas evidencia o potencial do mel de Aroeira produzido no norte de Minas Gerais para uso terapêutico, contribuindo para a agregação de valor e comercialização deste tipo de mel.

Overlap of latent pathogens in the Botryosphaeriaceae on a native and agricultural host.

Some species of the Botryosphaeriaceae are capable of infecting a broad range of host plants. We studied the species diversity of Botryosphaeriaceae associated with marula (Sclerocarya birrea subsp. caffra, Anacardiaceae) trees in South Africa over two seasons, as well as species common to both S. birrea and adjacent mango (Mangifera indica, Anacardiaceae) trees in a subset of sites. Gene flow amongst populations of Botryosphaeriaceae shared on these tree species was tested using microsatellite markers. Twelve species were identified from S. birrea and eleven species were found on M. indica trees. From isolations done in 2006, the dominant species on S. birrea was Neofusicoccum vitifusiforme, while N. parvum was the dominant species isolated from M. indica. Neofusicoccum parvum was dominant in isolations from both hosts in 2012. Isolates of Botryosphaeria fabicerciana, Lasiodiplodia mahajangana, L. pseudotheobromae, L. theobromae, N. mediterraneum, and N. umdonicola were also collected from both hosts. Population genetic analyses on isolates of N. parvum suggested that three populations were present, each comprising isolates from both hosts. There was significant gene flow between N. parvum populations on these hosts. This ability to infect multiple hosts and to migrate amongst them facilitates the establishment and spread of species and genotypes of the Botryosphaeriaceae, such as N. parvum, in new areas.

Pichia kudriavzevii as a representative yeast of North Patagonian winemaking terroir.

Terroir concept includes specific soil, topography, climate, landscape characteristics and biodiversity features. In reference to the last aspect, recent studies investigating the microbial biogeography (lately called 'microbial terroir') have revealed that different wine-growing regions maintain different microbial communities. The aim of the present work was to identify potential autochthonous fermentative yeasts isolated from native plants in North Patagonia, Schinus johnstonii, Ephedra ochreata and Lycium chilense, that could be associated to the specific vitivinicultural terroir of this region. Different Pichia kudriavzevii isolates were recovered from these plants and physiologically and genetically compared to regional wine isolates and foreign reference strains of the same species. All isolates were subjected to molecular characterization including mtDNA-RFLP, RAPD-PCR and sequence analysis. Both wine and native P. kudriavzevii isolates from Patagonia showed similar features, different from those showed by foreign strains, suggesting that this species could be part of a specific regional terroir from North Patagonia.

Influence of Culturing Conditions on Bioprospecting and the Antimicrobial Potential of Endophytic Fungi from Schinus terebinthifolius.

In this study, we analyzed the antimicrobial activity of extracts harvested from 17 endophytic fungi isolated from the medicinal plant Schinus terebinthifolius. Morphological and molecular analyses indicated that these fungal species belonged to the genera Alternaria, Bjerkandera, Colletotrichum, Diaporthe, Penicillium, and Xylaria. Of the endophytes analyzed, 64.7 % produced antimicrobial compounds under at least one of the fermentation conditions tested. Nine isolates produced compounds that inhibited growth of Staphylococcus aureus, four produced compounds that inhibited Candida albicans, and two that inhibited Pseudomonas aeruginosa. The fermentation conditions of the following endophytes were optimized: Alternaria sp. Sect. Alternata-LGMF626, Xylaria sp.-LGMF673, and Bjerkandera sp.-LGMF713. Specifically, the carbon and nitrogen sources, initial pH, temperature, and length of incubation were varied. In general, production of antimicrobial compounds was greatest when galactose was used as a carbon source, and acidification of the growth medium enhanced the production of compounds that inhibited C. albicans. Upon large-scale fermentation, Alternaria sp. Sect. Alternata-LGMF626 produced an extract containing two fractions that were active against methicillin-resistant S. aureus. One of the extracts exhibited high activity (minimum inhibitory concentration of 18.52 µg/mL), and the other exhibited moderate activity (minimum inhibitory concentration of 55.55 µg/mL). The compounds E-2-hexyl-cinnamaldehyde and two compounds of the pyrrolopyrazine alkaloids class were identified in the active fractions by gas chromatography-mass spectrometry.

Efeito modulador do extrato de plantas medicinais do gênero Spondias sobre a resistência de cepas de Staphylococcus aureus à Eritromicina / Modulatory effect of the extract of medicinal plants of Spondias genus on resistance of Staphylococcus aureus to Erythromycin

A acentuada resistência bacteriana gera uma necessidade de desenvolver novos fármacos e a pesquisa com plantas medicinais, como fontes de substâncias bioativas vêm sendo um indicativo para descoberta de eficientes agentes terapêuticos. Microrganismos do gênero Staphylococcus são cocos Gram positivos, que podem causar supurações, abscessos e diversas infecções piogênicas em humanos e animais. Assim, o objetivo deste trabalho foi analisar a atividade moduladora de extratos de plantas medicinais do gênero Spondias frente à Staphylococcus aureus resistentes a eritromicina. A concentração inibitória mínima e a capacidade de modular a resistência das cepas de S. aureus à Eritromicina foram avaliadas pelo método de microduluição. Os resultados mostraram que a associação de eritromicina com Spondias purpurea apresentou efeito sinérgico sobre as cepas SA04 e SA05. Enquanto que a Spondias mombin apresentou sinergismos sobre a ATCC, SA01, SA03 e SA05. O bioensaio com A. salina demonstrou que S. purpurea e S. mombin, apresentaram em CL 50 1000 e 482,5 ?g/ mL, respectivamente. Os resultados são promissores e sugerem que os extratos de espécies do gênero Spondias possuem potencial como agentes moduladores de resistência bacteriana.(AU)

The marked bacterial resistance generates a need to develop new drugs and research on medicinal plants as sources of bioactive substances has been an indication for efficient discovery of therapeutic agents. Microorganisms of the genus Staphylococcus are Gram positive coccus, which can cause suppuration, abscesses and various pyogenic infections in humans and animals. Thus, the objective of this study was to evaluate the modulatory activity of extracts of medicinal plants of genus Spondias against Staphylococcus aureus resistant to erythromycin. The minimum inhibitory concentration and modulating activity of the plant extracts studied and erythromycin were evaluated by the microdilution method. The results showed that the association of erythromycin with Spondias purpurea showed synergistic effect on the strains SA04 and SA05. While Spondias mombin showed synergism on the ATCC, SA01, SA03 and SA05 strain. The bioassay with A. saline showed that S. purpurea and S. mombin presented a LC50 1000 and 482.5 mg/ mL, respectively. The results are promising and suggest that that the extracts species of the genus Spondias agents have potential as modulator agents of bacterial resistance.(AU)

Lactobacillus plantarum 24, isolated from the marula fruit (Sclerocarya birrea), has probiotic properties and harbors genes encoding the production of three bacteriocins.

Lactobacillus plantarum 24, isolated from marula fruit grows at pH 4.0 and tolerates acid levels and bile concentrations normally present in the human gastro-intestinal tract. Wistar rats that have been administered L. plantarum 24 showed no signs of discomfort or abnormal behavior. Tissue samples from the liver, spleen and intestine appeared normal. Furthermore, strain 24 harbors the genes encoding plantaricins A, F, and NC8α, a gene encoding immunity to plantaricin, and an ABC transporter similar in sequence to that reported for plantaricin G. At least one antimicrobial peptide within the size range of plantaricins A, F, and NC8α has been detected on a tricine-SDS-PAGE gel. Little is known about the microbial population in marula. This is the first report of a L. plantarum strain from marula fruit with bacteriocin genes and probiotic properties.

Bacteriocin production by Pediococcus pentosaceus isolated from marula (Scerocarya birrea).

Strain ST44AM, isolated from marula, was identified as Pediococcus pentosaceus based on biochemical tests, sugar fermentation reactions (API 50CHL), PCR with species-specific primers and 16S rDNA sequencing. Strain ST44AM produces a 6.5 kDa class IIa bacteriocin, active against lactic acid bacteria, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Listeria innocua, Listeria ivanovii subsp. ivanovii and Listeria monocytogenes. The peptide is inactivated by proteolytic enzymes, but not when treated with alpha-amylase, Triton X-100, Triton X-114, SDS, Tween 20, Tween 80, urea, NaCl and EDTA. No change in activity was recorded after 2 h at pH values between 2.0 and 12.0, and after treatment at 100 degrees C for 120 min or 121 degrees C for 20 min. The mode of activity against L. ivanovii susbp. ivanovii ATCC19119 and Enterococcus faecium HKLHS is bactericidal, resulting in cell lyses and enzyme- and DNA-leakage. No significant differences in cell growth and bacteriocin production were observed when strain ST44AM was cultured in MRS broth at 26 degrees C, 30 degrees C and 37 degrees C for 24 h and tested against the same target strain. L. ivanovii subsp. ivanovii ATCC 19119 and E. faecium HKLHS did, however, differ in sensitivity to bacteriocin ST44AM (3.3x10(6) AU/mL and 2.6x10(4) AU/mL, respectively). Peptide ST44AM adsorbs at high levels (1600 AU/mL) to producer cells. Bacteriocin ST44AM may be a derivative of pediocin PA-1. This is the first report on the presence of P. pentosaceus in marula and a pediocin PA-1 derivative produced by this species. We are also the first to report on the synergetic effect ciprofloxacin has on a pediocin-like bacteriocin.

Polyphasic characterization of xanthomonads pathogenic to members of the Anacardiaceae and their relatedness to species of Xanthomonas.

We have used amplified fragment length polymorphism (AFLP), multilocus sequence analysis (MLSA) and DNA-DNA hybridization for genotypic classification of Xanthomonas pathovars associated with the plant family Anacardiaceae. AFLP and MLSA results showed congruent phylogenetic relationships of the pathovar mangiferaeindicae (responsible for mango bacterial canker) with strains of Xanthomonas axonopodis subgroup 9.5. This subgroup includes X. axonopodis pv. citri (synonym Xanthomonas citri). Similarly, the pathovar anacardii, which causes cashew bacterial spot in Brazil, was included in X. axonopodis subgroup 9.6 (synonym Xanthomonas fuscans). Based on the thermal stability of DNA reassociation, consistent with the AFLP and MLSA data, the two pathovars share a level of similarity consistent with their being members of the same species. The recent proposal to elevate X. axonopodis pv. citri to species level as X. citri is supported by our data. Therefore, the causal agents of mango bacterial canker and cashew bacterial spot should be classified as pathovars of X. citri, namely X. citri pv. mangiferaeindicae (pathotype strain CFBP 1716) and X. citri pv. anacardii (pathotype strain CFBP 2913), respectively. Xanthomonas fuscans should be considered to be a later heterotypic synonym of Xanthomonas citri.

[Biotic and abiotic factors that affect the quality of Schinopsis balansae Engl. and Aspidosperma quebracho-blanco Schltdl. seeds]. / Factores bióticos y abióticos que afectan la calidad de las semillas de Schinopsis balansae Engl. y Aspidosperma quebracho-blanco Schltdl.

Aspidosperma quebracho-blanco (white quebracho) and Schinopsis balansae (red quebracho) are distinctive trees of the South American Park in Argentina. Quebrachos are found in forests that have been exploited very intensively. The object of this work was the identification of biotic and abiotic factors specially fungal pathogen that affect the quality of both species and its relation with germination. Seeds where evaluated through germination test and the percentage of the incidence of fungal agents in two different years of harvest was determined. In S. balansae the germination rate was 77% and of 27% in 2000 and 2001 harvests, respectively. Associations fungi-germination were found in 2001 for Alternaria spp., Curvularia spp., and Fusarium spp., showing an coefficient of correlation = -0.84; -0.85 and -0.73 (p < 0.00004), respectively. A high percentage of vane seeds (55%) was also found in 2001 harvest, due to adverse environmental factors, specifically higher precipitations during flowering. In A. quebracho-blanco seeds, the germination rate was 50% and 90% in 2000 and 2003 respectively, with a 42% of immature seeds in 2000 harvest that was associated to high precipitations and high temperatures during flowering and ripping of fruits. The incidence of pathogens was low and did not have association to germination.

Antimicrobial evaluation of fungal extracts produced by endophytic strains of Phomopsis sp.

Crude extract of cultures of 13 fungal strains identified as Phomopsis sp. and isolated as endophytes from the leaves of Aspidosperma tomentosum and twigs of Spondias mombin were examined for their antibacterial and antifungal activities. The screening was conducted using the bioautographic TLC agar-overlay technique against bacteria (E. coli, P. aeruginosa, S. aureus), yeast (C. albicans, S. cerevisiae), and readily adapted for use with filamentous fungi (A. niger, F. oxysporum). Three of the 13 extracts effectively inhibited the growth of all test-organisms, indicating that they may represent a potential for pharmaceutical and/or agricultural applications and are worthy of further study.

Candida sergipensis, a new asexual yeast species isolated from frozen pulps of tropical fruits.

Sixteen strains of the new yeast species Candida sergipensis have been isolated from frozen pulps of the tropical fruits umbú ( Spondias tuberosa Avr. Cam.) and mangaba ( Hancornia speciosa Gom.). Candida sergipensis was one of the prevalent species in the yeast community of these substrates. The new asexual ascomycetous yeast is phylogenetically related to Candida spandovensis and Candida sorbophila, species belonging to the Wickerhamiella clade, as evidenced by the sequences of the D1/D2 domains of their large subunit ribosomal DNAs. The species C. sergipensis and C. spandovensis can be separated on the basis of growth on 50% glucose agar, xylose and succinate, negative for the first species and positive for the second. The type culture is strain UFMG-R188 (CBS 9567).