Transcriptional response of Fusarium oxysporum and Neocosmospora solani challenged with amphotericin B or posaconazole.

Some species of fusaria are well-known pathogens of humans, animals and plants. Fusarium oxysporum and Neocosmospora solani (formerly Fusarium solani) cause human infections that range from onychomycosis or keratitis to severe disseminated infections. In general, these infections are difficult to treat due to poor therapeutic responses in immunocompromised patients. Despite that, little is known about the molecular mechanisms and transcriptional changes responsible for the antifungal resistance in fusaria. To shed light on the transcriptional response to antifungals, we carried out the first reported high-throughput RNA-seq analysis for F. oxysporum and N. solani that had been exposed to amphotericin B (AMB) and posaconazole (PSC). We detected significant differences between the transcriptional profiles of the two species and we found that some oxidation-reduction, metabolic, cellular and transport processes were regulated differentially by both fungi. The same was found with several genes from the ergosterol synthesis, efflux pumps, oxidative stress response and membrane biosynthesis pathways. A significant up-regulation of the C-22 sterol desaturase (ERG5), the sterol 24-C-methyltransferase (ERG6) gene, the glutathione S-transferase (GST) gene and of several members of the major facilitator superfamily (MSF) was demonstrated in this study after treating F. oxysporum with AMB. These results offer a good overview of transcriptional changes after exposure to commonly used antifungals, highlights the genes that are related to resistance mechanisms of these fungi, which will be a valuable tool for identifying causes of failure of treatments.

Genome-Wide Association Study Identifies Single Nucleotide Polymorphism Markers Associated with Mycelial Growth (at 15, 20, and 25°C), Mefenoxam Resistance, and Mating Type in Phytophthora infestans.

Phenotypic diversity among individuals defines the potential for evolutionary selection in a species. Phytophthora infestans epidemics are generally thought to be favored by moderate to low temperatures, but temperatures in many locations worldwide are expected to rise as a result of global climate change. Thus, we investigated variation among individuals of P. infestans for relative growth at different temperatures. Isolates of P. infestans came from three collections: (i) individual genotypes recently dominant in the United States, (ii) recently collected individuals from Central Mexico, and (iii) progeny of a recent sexual recombination event in the northeastern United States. In general, these isolates had optimal mycelial growth rates at 15 or 20°C. However, two individuals from Central Mexico grew better at higher temperatures than did most others and two individuals grew relatively less at higher temperatures than did most others. The isolates were also assessed for mefenoxam sensitivity and mating type. Each collection contained individuals of diverse sensitivities to mefenoxam and individuals of the A1 and A2 mating type. We then searched for genomic regions associated with phenotypic diversity using genotyping-by-sequencing. We found one single nucleotide polymorphism (SNP) associated with variability in mycelial growth at 20°C, two associated with variability in mycelial growth at 25°C, two associated with sensitivity to mefenoxam, and one associated with mating type. Interestingly, the SNPs associated with mefenoxam sensitivity were found in a gene-sparse region, whereas the SNPs associated with growth at the two temperatures and mating type were found both at more gene-dense regions.

Multiscale design of a dairy beverage model composed of Candida utilis single cell protein supplemented with oleic acid.

One of the main challenges in the food industry is to design strategies for the successful incorporation of natural sources of bioactive compounds. Recently, yogurts and other fermented dairy beverages have been proposed as ideal carriers of such bioactive compounds such as fatty acids and antioxidants that could improve consumers' health. However, the incorporation of new ingredients causes functional and structural modifications that may affect the consumers' preferences. In this work, a dairy beverage model supplemented with oleic acid has been designed by partial substitution of milk by Candida utilis single-cell protein extract. The changes in the structural properties of this new beverage were evaluated by following the fermentation process, pH, aggregate size, microstructure, and changes in rheological properties. Furthermore, molecular dynamics simulations were carried out to analyze the interaction between its main components. Our data revealed that samples with a percentage of milk substitution of 30% showed a higher viscosity as compared with the other percentages and less viscosity than the control (no substitution). These samples were then selected for fortification by incorporating oleic acid microcapsules. A concentration of 1.5 g/100 g was shown to be the optimal quantity of microcapsules for oleic acid supplementation. Molecular dynamic simulations revealed glutathione as an important component of the micro-gel structure. The present study forms the basis for novel studies where Candida utilis single-cell protein and microencapsulated essential oils could be used to design innovative bioproducts.

Description of Alicyclobacillus montanus sp. nov., a mixotrophic bacterium isolated from acidic hot springs.

Three morphologically similar thermo-acidophilic strains, USBA-GBX-501, USBA-GBX-502 and USBA-GBX-503T, were isolated from acidic thermal springs at the National Natural Park Los Nevados (Colombia). All isolates were spore-forming, Gram-stain-positive and motile, growing aerobically at 25-55 °C (optimum ~45 °C) and at pH 1.5-4.5 (optimum pH ~3.0). Phylogenetic analysis of the 16S rRNA gene sequences of these isolates showed an almost identical sequence (99.0 % similarity) and they formed a robust cluster with the closest relative Alicyclobacillus tolerans DSM 16297T with a sequence similarity of 99.0 %. Average similarity to other species of the genus Alicyclobacillus was 93.0 % and average similarity to species of the genus Effusibacillus was 90 %. In addition, the level of DNA-DNA hybridization between strain USBA-GBX-503T and Alicyclobacillus tolerans DSM 16297T was 31.7 %. The genomic DNA G+C content of strain USBA-GBX-503T was 44.6 mol%. The only menaquinone was MK-7 (100.0 %). No ω-alicyclic fatty acids were detected in strain USBA-GBX-503T, and the major cellular fatty acids were C18 : 1ω7c, anteiso-C17 : 0 and iso-C17 : 0. Based on phenotypic and chemotaxonomic characteristics, phylogenetic analysis and DNA-DNA relatedness values, along with low levels of identity at the whole genome level (ANIb and ANIm values of <67.0 and <91.0 %, respectively), it can be concluded that strain USBA-GBX-503T represents a novel species of the genus Alicyclobacillus, for which the name Alicyclobacillus montanus sp. nov. is proposed. The type strain is USBA-GBX-503T (=CMPUJ UGB U503T=CBMAI1927T).

The effect of cyclic heat treatment on the physicochemical properties of bio hydroxyapatite from bovine bone.

This paper focus on physicochemical changes in bio-hydroxyapatite (BIO-HAp) from bovine femur obtained by calcination at high temperatures: 520-620 (each 20 °C) at 7.4 °C/min and from 700 to 1100 °C (each 100 °C) at three heating rates: 7.4, 9.9, and 11.1 °C/min. BIO-HAp samples were obtained using a multi-step process: cleaning, milling, hydrothermal process, calcination in an air atmosphere, and cooling in furnace air. Inductively Couple Plasma (ICP) showed that the presence of Mg, K, S, Ba, Zn, and Na, is not affected by the annealing temperature and heating rate. While Scanning Electron Microscopy (SEM) images showed the continuous growth of the HAp crystals during the calcination process due to the coalescence phenomenon, and the Full Width at the Half Maximum for the X-ray patterns for temperatures up to 700 is affected by the annealing temperature and the heating rate. Through X-ray diffraction, thermal, and calorimetric analysis (TGA-DSC), a partial dehydroxylation of hydroxyapatite was found in samples calcined up to 900 °C for the three heating rates. Also, Ca/P molar ratio decreased for samples calcined up to 900 °C as a result of the dehydroxylation process. NaCaPO4, CaCO3, Ca3(PO4)2, MgO, and Ca(H2PO4)2 are some phases identified by X-ray diffraction; some of them are part of the bone and others were formed during the calcination process as a function of annealing temperature and heating rate, as it is the case for MgO.

Phytophthora betacei, a new species within Phytophthora clade 1c causing late blight on Solanum betaceum in Colombia.

Over the past few years, symptoms akin to late blight disease have been reported on a variety of crop plants in South America. Despite the economic importance of these crops, the causal agents of the diseases belonging to the genus Phytophthora have not been completely characterized. In this study, a new Phytophthora species was described in Colombia from tree tomato (Solanum betaceum), a semi-domesticated fruit grown in northern South America. Comprehensive phylogenetic, morphological, population genetic analyses, and infection assays to characterize this new species, were conducted. All data support the description of the new species, Phytophthora betacei sp. nov. Phylogenetic analyses suggest that this new species belongs to clade 1c of the genus Phytophthora and is a close relative of the potato late blight pathogen, P. infestans. Furthermore, it appeared as the sister group of the P. andina strains collected from wild Solanaceae (clonal lineage EC-2). Analyses of morphological and physiological characters as well as host specificity showed high support for the differentiation of these species. Based on these results, a complete description of the new species is provided and the species boundaries within Phytophthora clade 1c in northern South America are discussed.

Publisher's Note: Driven Open Quantum Systems and Floquet Stroboscopic Dynamics [Phys. Rev. Lett. 117, 250401 (2016)].

This corrects the article DOI: 10.1103/PhysRevLett.117.250401.

Driven Open Quantum Systems and Floquet Stroboscopic Dynamics.

We provide an analytic solution to the problem of system-bath dynamics under the effect of high-frequency driving that has applications in a large class of settings, such as driven-dissipative many-body systems. Our method relies on discrete symmetries of the system-bath Hamiltonian and provides the time evolution operator of the full system, including bath degrees of freedom, without weak-coupling or Markovian assumptions. An interpretation of the solution in terms of the stroboscopic evolution of a family of observables under the influence of an effective static Hamiltonian is proposed, which constitutes a flexible simulation procedure of nontrivial Hamiltonians. We instantiate the result with the study of the spin-boson model with time-dependent tunneling amplitude. We analyze the class of Hamiltonians that may be stroboscopically accessed for this example and illustrate the dynamics of system and bath degrees of freedom.

Differential PbP27 expression in the yeast and mycelial forms of the Paracoccidioides brasiliensis species complex.

p27 is an antigenic protein produced by Paracoccidioides brasiliensis, the etiologic agent of paracoccidioidomycosis (PCM). Despite its unknown function, it has been suggested as a putative virulence factor, proposed as a suitable target for the design of diagnostic tools and vaccines, and considered as an enhancer in antifungal treatment of PCM. We evaluated sequence polymorphisms of PbP27 gene sequence among isolates, finding some polymorphisms associated with the isolates' phylogenetic origin. In order to determine if there was a differential expression pattern between morphological states and among isolates, we also evaluated PbP27 expression, at transcriptional and translational levels, in mycelia and yeast cultures in 14 isolates belonging to the P. brasiliensis species complex (S1, PS2, PS3, and "Pb01-like", proposed to be named Paracoccidioides lutzii) by two techniques, real time RT-PCR (RT-qPCR) and protein dot blot. For the latter, four protein extracts from different cell localizations (SDS or ß-mercaptoethanol, cytoplasmic and extracellular proteins) were analyzed for each isolate. p27 was present in the four extracts evaluated, mainly in the SDS extract, corresponding to an extract containing proteins loosely attached to the cell wall. This information correlates with immunohistochemical analysis, where positive staining of the yeasts' cell wall was observed. We found that p27 was present in all isolates, mainly in the yeast form. This pattern was corroborated by RT-qPCR results, with higher expression levels found in the yeast form for most of the isolates. The results provide new insights into the expression patterns of this protein, and further characterize it in view of potential uses as a diagnostic and/or therapeutic tool.

Selection of antagonistic bacteria isolated from the Physalis peruviana rhizosphere against Fusarium oxysporum.

AIMS: Cape gooseberries (Physalis peruviana) have become increasingly important in Colombia for both domestic consumption and the international export market. Vascular wilting caused by Fusarium oxysporum is the most damaging disease to P. peruviana crops in Colombia. The control of this pathogen is mainly carried out by chemical and cultural practices, increasing production costs and generating resistance. Therefore, the objectives of this study were to test rhizobacteria isolates from P. peruviana rhizosphere against F. oxysporum under in vitro and in vivo conditions. METHODS AND RESULTS: Over 120 strains were isolated, and five were selected for their high inhibition of F. oxysporum growth and conidia production under in vitro conditions. These strains inhibited growth by 41-58% and reduced three- to fivefold conidia production. In the in vivo assays, all the tested isolates significantly reduced fungal pathogenicity in terms of virulence. Isolate B-3.4 was the most efficient in delaying the onset of the first symptoms. All isolates were identified as belonging to the genus Pseudomonas except for A-19 (Bacillus sp.). CONCLUSIONS: Our results confirmed that there are prospective rhizobacteria strains that can be used as biological control agents; some of them being able to inhibit in vitro F. oxysporum growth and sporulation. SIGNIFICANCE AND IMPACT OF THE STUDY: Incorporating these bacteria into biological control strategies for the disease that causes high economical losses in the second most exported fruit from Colombia would result in a reduced impact on environment and economy.

First Report of Phytophthora infestans Causing Late Blight on Solanum viarum in Colombia.

Solanum viarum Dunal (tropical soda apple) belongs to the section Acanthophora in the genus Solanum, which includes nearly 20 neotropical species of herbs and small shrubs (2). The species in this section are sometimes called the 'spiny Solanums' (2) and are adapted mainly to highly disturbed habitats and open secondary forests. The center of diversity is eastern Brazil (3). Since the early 1990s, S. viarum has been a problematic weed in Florida where it was listed as a noxious weed in 1993, followed in 1994 by its addition to the Federal Noxious Weed List of the USDA. On 17 April 2010, 12 plants of S. viarum located close to a S. betaceum crop (tree tomato) in the province of Caldas (Department of Antioquia, central northwestern Colombia) were found with symptoms similar to late blight caused by Phytophthora infestans on S. tuberosum (potato). Fifteen leaves from 12 plants with blackish, water-soaked lesions showing a white sporulation on the abaxial side were collected and processed within 3 days. The leaves were placed in a humid chamber and incubated in darkness at room temperature (18°C mean temperature) until sporulation was observed. Microscopic characteristics were consistent with Phytophthora spp. Only one axenic culture was obtained by successive subcultures in rye B agar plates. After an incubation period of 8 days, plates were washed with distilled water and ovoid, semipapillate caduceus sporangia ranging from 38 to 41 µm long (average 39; N = 86) and 23 to 29 µm wide (average 26; N = 86) were observed. To fulfill Koch's postulates and test the isolate for the ability to infect potato as well as Solanum spp. associated with potato crops in Colombia, triplicate pathogenicity tests were carried out on three detached leaves of S. viarum, S. tuberosum, and S. americanum (American nightshade). A 1 × 104 sporangia/ml suspension of the Phytophthora isolate, estimated using a haemocytometer, was obtained from 8-day-old cultures grown on rye B agar. The suspension was incubated at 4°C for 2 h to induce zoospore release. The leaves were then inoculated by spraying them until runoff. After an incubation period of 5 days at 18°C in a humidity chamber, mycelia, sporangia, and brownish lesions, similar to those described above, were observed in the leaves of all three hosts, indicating pathogenicity. DNA extraction was performed from the P. infestans isolate (4). Four nuclear loci, ITS, ß-tubulin, Ras, and Avr3a, as well as one mitochondrial gene, cytochrome c oxidase 1 (Cox1), were amplified and sequenced. Sequences were compared with GenBank databases using Blastn. In all cases, the best hits corresponded to P. infestans (GenBank Accession No. HQ639930 for Avr3A, HQ639931 for ß-tubulin, HQ639932 for Cox1, HQ639933 for iRas, HQ639934 for Ras, and JF419363 for ITS). Reports of P. infestans causing typical late blight symptoms on wild solanaceous plants are becoming more frequent and have been made from other countries such as Peru (1). To our knowledge, this is the first time that P. infestans has been observed and isolated from S. viarum in Colombia, introducing the possibility of this wild solanaceous weed as another late blight host. References: (1) G. Garry et al. Eur. J. Plant Pathol. 113:71, 2005. (2) R. Levin et al. Am. J. Bot. 92:603, 2005. (3) M. Nee. A Revision of Solanum Section Acanthophora. Ph.D. diss. University of Wisconsin, Madison, 1979. (4) A. M. Vargas et al. Phytopathology 99:82, 2009.

Effect of bioactive compounds extracted from Cordyceps nidus ANDES-F1080 on laccase activity of Pleurotus ostreatus ANDES-F515.

Laccases are ligninolytic enzymes produced by different microorganisms, especially by fungi such as the white-rot fungus Pleurotus ostreatus. Chemical inductors have been used to promote laccase secretion due to the application of these enzymes in lignocellulosic biomass pretreatment. Cordyceps nidus ANDES-F1080 was previously described as a source of bioactive compounds that could influence the enzymatic production system of other fungi. For that reason, this study evaluates the effect of C. nidus' ANDES-F1080 extracts on the laccase activity of P. ostreatus ANDES-F515. To achieve this objective, C. nidus ANDES-F1080 was grown in four different substrates: two artificial-based and two natural-based culture media. Metabolites were extracted from C. nidus ANDES-F1080 using water and methanol as solvents. Biochemical characterization of these extracts was performed to complement the analysis of their effect on laccase activity. Our results revealed an enhancement on the laccase activity of P. ostreatus ANDES-F515 grown in natural-based cultures when C. nidus' ANDES-F1080 extracts were supplemented. The best laccase activities registered values around 10,575 ±â€¯813 U·L-1.

Physiological and molecular characterization of atypical isolates of Malassezia furfur.

The species constituting the genus Malassezia are considered to be emergent opportunistic yeasts of great importance. Characterized as lipophilic yeasts, they are found in normal human skin flora and sometimes are associated with different dermatological pathologies. We have isolated seven Malassezia species strains that have a different Tween assimilation pattern from the one typically used to differentiate M. furfur, M. sympodialis, and M. slooffiae from other Malassezia species. In order to characterize these isolates of Malassezia spp., we studied their physiological features and conducted morphological and molecular characterization by PCR-restriction fragment length polymorphism and sequencing of the 26S and 5.8S ribosomal DNA-internal transcribed spacer 2 regions in three strains from healthy individuals, four clinical strains, and eight reference strains. The sequence analysis of the ribosomal region was based on the Blastn algorithm and revealed that the sequences of our isolates were homologous to M. furfur sequences. To support these findings, we carried out phylogenetic analyses to establish the relationship of the isolates to M. furfur and other reported species. All of our results confirm that all seven strains are M. furfur; the atypical assimilation of Tween 80 was found to be a new physiological pattern characteristic of some strains isolated in Colombia.

First Report of Late Blight Caused by Phytophthora infestans on Cape Gooseberry (Physalis peruviana) in Colombia.

Late blight caused by Phytophthora infestans is the most limiting disease for several species of the Solanaceae family in Colombia. A potential host for P. infestans is Cape gooseberry (Physalis peruviana), a species belonging to the Solanaceae family. Its center of origin is the highlands of Peru and it is grown at approximately 1,500 to 3,000 m above sea level. Cape gooseberry has become an important export fruit in Colombia. Consequently, in the last few years, the area cultivated with Physalis peruviana has increased dramatically. P. infestans was isolated from this crop in the province of Cundinamarca, Colombia. Symptoms caused by this oomycete appeared initially on the leaf margins as small, irregular, necrotic spots that expanded and merged, increasing the necrotic area. These spots had a soft texture resulting from the degradation of plant tissue by the pathogen. On old lesions, white mycelia and sporangia were observed. Affected plants were rarely killed, but under favorable conditions, severe symptoms were observed in leaves and yield was reduced. Ten isolates were obtained from infected tissue by placing a lesion directly on a potato slice in a moist chamber (2). Mycelia grown on the potato slice were then transferred to rye agar. Identification of the pathogen was performed based on morphological characteristics, specifically, sporangiophores of P. infestans are compoundly branched and develop sympodially, with swellings at the points where sporangia were attached (1). Further confirmation was obtained by sequencing the internal transcribed spacer (ITS) regions (GenBank Accession Nos. EF173467-EF173476). Koch's postulates were completed in the laboratory by spray inoculating detached leaves of Cape gooseberry with a zoospore suspension obtained from each of the 10 isolates. Inoculum was prepared by flooding 10-day-old cultures with sterile distilled water to obtain a 104/ml sporangial suspension followed by zoospore induction at 4°C. Leaves were sprayed with this suspension, placed in moist chambers, and incubated at 20°C in the dark. Control leaves were sprayed with sterile distilled water. Two separate leaves were inoculated with each isolate. The pathogen was reisolated from leaf lesions in all cases. The period between infection and the appearance of symptoms ranged from 5 to 7 days. To our knowledge, this is the first report of P. infestans causing damage on Cape gooseberry in Colombia. Chemical control measures are to some extent successfully applied in most regions where solanaceous crops are grown in Colombia. Nevertheless, suitable disease management for Physalis peruviana has not been achieved and further studies on the epidemiology of the disease on this new host are needed. References: (1) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society. St. Paul, MN, 1996. (2) G. A. Forbes et al. Phytopathology 87:375, 1997.

Highly efficient transformation system for Malassezia furfur and Malassezia pachydermatis using Agrobacterium tumefaciens-mediated transformation.

Malassezia spp. are part of the normal human and animal mycobiota but are also associated with a variety of dermatological diseases. The absence of a transformation system hampered studies to reveal mechanisms underlying the switch from the non-pathogenic to pathogenic life style. Here we describe, a highly efficient Agrobacterium-mediated genetic transformation system for Malassezia furfur and M. pachydermatis. A binary T-DNA vector with the hygromycin B phosphotransferase (hpt) selection marker and the green fluorescent protein gene (gfp) was introduced in M. furfur and M. pachydermatis by combining the transformation protocols of Agaricus bisporus and Cryptococcus neoformans. Optimal temperature and co-cultivation time for transformation were 5 and 7days at 19°C and 24°C, respectively. Transformation efficiency was 0.75-1.5% for M. furfur and 0.6-7.5% for M. pachydermatis. Integration of the hpt resistance cassette and gfp was verified using PCR and fluorescence microscopy, respectively. The T-DNA was mitotically stable in approximately 80% of the transformants after 10 times sub-culturing in the absence of hygromycin. Improving transformation protocols contribute to study the biology and pathophysiology of Malassezia.

Description of a new anaerobic thermophilic bacterium, Thermoanaerobacterium butyriciformans sp. nov.

Strain USBA-019T, an anaerobic and thermophilic strain, was identified as a new member of the genus Thermoanaerobacterium. USBA-019T cells are gram-positive, strictly anaerobic, thermophilic, chemoorganotrophic, moderately acidophilic, non-motile, endospore-forming, slightly curved, and rod-shaped. Cells measure 0.4×3.0-7.0µm. Optimal growth occurs at 50-55°C (35-65°C). Optimum pH is 5.0-5.5 (4.0-8.5). Thiosulfate, elemental sulfur and nitrate were utilized as electron acceptors. Fermentation of glucose, lactose, cellobiose, galactose, arabinose, xylose, starch and xylan primarily produced acetate and butyrate. Xylan, starch and cellobiose produced ethanol and starch, cellobiose, galactose, arabinose and mannose produced lactic acid. Phylogenetic analyses based on 16S rRNA gene sequence comparison and genomic relatedness indices show the close relation of USBA-019T to Thermoanaerobacterium thermostercoris and Thermoanaerobacterium aotearoense (similarity value: 99%). Hybridization of USBA-019T, Th. thermostercoris DSM22141T and Th. aotearoense DMS10170T found DNA-DNA relatedness of 33.2% and 18.2%, respectively. Based on phenotypic, chemotaxonomic and phylogenetic evidence, along with low identity at whole genome level, USBA-019T is a novel species of the genus Thermoanaerobacterium which we propose to name Thermoanaerobacterium butyriciformans sp. nov. The type strain is USBA-019T (=CMPUJ U-019T=DSM 101588T).

Gene profiling of a compatible interaction between Phytophthora infestans and Solanum tuberosum suggests a role for carbonic anhydrase.

Late blight of potato, caused by the oomycete pathogen Phytophthora infestans, is a devastating disease that can cause the rapid death of plants. To investigate the molecular basis of this compatible interaction, potato cDNA microarrays were utilized to identify genes that were differentially expressed in the host during a compatible interaction with P. infestans. Of the 7,680 cDNA clones represented on the array, 643 (12.9%) were differentially expressed in infected plants as compared with mock-inoculated control plants. These genes were classified into eight groups using a nonhierarchical clustering method with two clusters (358 genes) generally down-regulated, three clusters (241 genes) generally up-regulated, and three clusters (44 genes) with a significant change in expression at only one timepoint. Three genes derived from two down-regulated clusters were evaluated further, using reverse transcription real-time polymerase chain reaction analysis. For these analyses, both incompatible and compatible interactions were included to determine if suppression of these genes was specific to compatibility. One gene, plastidic carbonic anhydrase (CA), was found to have a very different expression pattern in compatible vs. incompatible interactions. Virus-induced gene silencing was used to suppress expression of this gene in Nicotiana benthamiana. In CA-silenced plants, the pathogen grew more quickly, indicating that suppression of CA increases susceptibility to P. infestans.

Partial resistance of tomato to Phytophthora infestans is not dependent upon ethylene, jasmonic acid, or salicylic acid signaling pathways.

We compared tomato defense responses to Phytophthora infestans in highly compatible and partially compatible interactions. The highly compatible phenotype was achieved with a tomato-specialized isolate of P. infestans, whereas the partially compatible phenotype was achieved with a nonspecialized isolate. As expected, there was induction of the hypersensitive response (HR) earlier during the partially compatible interaction. However, contrary to our expectation, pathogenesis-related (PR) gene expression was not stimulated sooner in the partially compatible interaction. While the level of PR gene expression was quite similar in the two interactions, the LeDES gene (which encodes an enzyme necessary for the production of divinyl ethers) was expressed at a much higher level in the partially compatible interaction at 48 h after inoculation. Host reaction to the different pathogen genotypes was not altered (compared with wild type) in mutant tomatoes that were ethylene-insensitive (Never-ripe) or those with reduced ability to accumulate jasmonic acid (def-1). Similarly, host reaction was not altered in NahG transgenic tomatoes unable to accumulate salicylic acid. These combined data indicate that partial resistance in tomato to P. infestans is independent of ethylene, jasmonic acid, and salicylic acid signaling pathways.

Experimental pulmonary fibrosis induced by Paracoccidioides brasiliensis conidia: measurement of local host responses.

Pulmonary fibrosis was induced following inoculation of Paracoccidioides brasiliensis conidia intranasally in BALB/c mice. Fibrosis was associated with formation of granulomas, increase in lung hydroxyproline, and sustained increases in tissue tumor necrosis factor-alpha and transforming growth factor-beta. This study suggests a role for these cytokines in generation of pulmonary fibrosis associated with chronic granulomatous infectious diseases.

Measuring the Genetic Diversity of Xanthomonas axonopodis pv. manihotis Within Different Fields in Colombia.

ABSTRACT Cassava bacterial blight, caused by Xanthomonas axonopodis pv. manihotis, is a widespread disease that affects cassava (Manihot esculenta). We collected 238 X. axonopodis pv. manihotis strains by intensively sampling single fields in four edaphoclimatic zones (ECZs) in Colombia. DNA polymorphism of different X. axonopodis pv. manihotis populations was assessed by restriction fragment length polymorphism (RFLP) analyses, repetitive sequence-based polymerase chain reaction (rep-PCR), and amplified fragment length polymorphism (AFLP) assays. Genetic diversity, phenetic relationships among strains, and the coefficient of genetic differentiation were determined. All strains were tested for aggressiveness on the susceptible cassava cv. MCOL 1522. Strains were also tested for virulence on cassava differentials adapted to the strains' respective ECZs. Our study showed that the Colombian X. axonopodis pv. manihotis population has a high degree of genetic diversity. The hierarchical analysis of diversity showed genotypic differentiation at all levels, among ECZs, among fields within ECZs, and among strains within fields planted to several cassava genotypes. New RFLP haplotypes were detected, leading to the characterization of a new pathotype. Dendrograms from AFLP were more robust than those from RFLP data. A close association between the strains' geographical origin and DNA polymorphism was obtained using RFLP and AFLP data. We suggest that the host played a role in causing pathogen differentiation.