Bisphenol A in the environment and recent advances in biodegradation by fungi.

Bisphenol A (BPA) is a compound used in the manufacture of a wide variety of everyday materials that, when released into the environment, causes multiple detrimental effects on humans and other organisms. The reason for this review is to provide an overview of the presence, distribution, and concentration of BPA in water, soil, sediment, and air, as well as the process of release and migration, biomagnification, and exposure mechanisms that cause various toxic effects in humans. Therefore, it is important to seek efficient and economic strategies that allow its removal from the environment and prevent it from reaching humans through food chains. Likewise, the main removal techniques are analyzed, focusing on biological treatments, particularly the most recent advances in the degradation of BPA in different environmental matrices through the use of ligninolytic fungi, non-ligninolytic fungi and yeasts, as well as the possible routes of metabolic processes that allow their biotransformation or biodegradation due to their efficient extracellular enzyme systems. This review supports the importance of the application of new biotechnological tools for the degradation of BPA.

Different histone deacetylase inhibitors reduce growth, virulence as well as changes in the morphology of the fungus Macrophomina phaseolina (Tassi) Goid.

Fungal phytopathogens require different skills to infect plants and complete their lifecycle. Some proteins in fungi are essential for pathogenesis and their expression is regulated by epigenetic mechanisms via chromatin-remodeling. Macrophomina phaseolina is an important phytopathogenic fungus that leads to considerable losses of different crops, especially during drought conditions. Some biological features of the fungus have been described. However, the epigenetics mechanisms involved in the development and virulence of M. phaseolina have not been fully studied. In this work, chemical inhibition was used to evaluate the role of histone deacetylases (HDACs) in the biology of M. phaseolina. The effect of two histone deacetylase inhibitors (iHDAC), valproic acid (VPA) and sodium butyrate (SBT), was analyzed. The results showed that the treated fungus presented a decrease in microsclerotia diameter, aerial mycelia production, vegetative growth, and cell pigmentation. In addition, VPA and SBT also affected the ability of the fungus to grow on complex carbon sources and virulence in the bean variety, BAT 477. Thus, it can be concluded that the alteration of histone deacetylation by VPA and SBT affects M. phaseolina growth, morphology, and virulence.

Epidemiology, control, and prevention of Newcastle disease in endemic regions: Latin America.

Newcastle disease (ND) infects wild birds and poultry species worldwide, severely impacting the economics of the poultry industry. ND is especially problematic in Latin America (Mexico, Colombia, Venezuela, and Peru) where it is either endemic or re-emerging. The disease is caused by infections with one of the different strains of virulent avian Newcastle disease virus (NDV), recently renamed Avian avulavirus 1. Here, we describe the molecular epidemiology of Latin American NDVs, current control and prevention methods, including vaccines and vaccination protocols, as well as future strategies for control of ND. Because the productive, cultural, economic, social, and ecological conditions that facilitate poultry endemicity in South America are similar to those in the developing world, most of the problems and control strategies described here are applicable to other continents.

Construction of PAH-degrading mixed microbial consortia by induced selection in soil.

Bioremediation of polycyclic aromatic hydrocarbons (PAHs)-contaminated soils through the biostimulation and bioaugmentation processes can be a strategy for the clean-up of oil spills and environmental accidents. In this work, an induced microbial selection method using PAH-polluted soils was successfully used to construct two microbial consortia exhibiting high degradation levels of low and high molecular weight PAHs. Six fungal and seven bacterial native strains were used to construct mixed consortia with the ability to tolerate high amounts of phenanthrene (Phe), pyrene (Pyr) and benzo(a)pyrene (BaP) and utilize these compounds as a sole carbon source. In addition, we used two engineered PAH-degrading fungal strains producing heterologous ligninolytic enzymes. After a previous selection using microbial antagonism tests, the selection was performed in microcosm systems and monitored using PCR-DGGE, CO2 evolution and PAH quantitation. The resulting consortia (i.e., C1 and C2) were able to degrade up to 92% of Phe, 64% of Pyr and 65% of BaP out of 1000 mg kg-1 of a mixture of Phe, Pyr and BaP (1:1:1) after a two-week incubation. The results indicate that constructed microbial consortia have high potential for soil bioremediation by bioaugmentation and biostimulation and may be effective for the treatment of sites polluted with PAHs due to their elevated tolerance to aromatic compounds, their capacity to utilize them as energy source.

Complete genome sequence of a non-pathogenic strain of Fowl Adenovirus serotype 11: Minimal genomic differences between pathogenic and non-pathogenic viruses.

In this study, we conducted the clinicopathological characterization of a non-pathogenic FAdV-D serotype 11 strain MX95, isolated from healthy chickens, and its entire genome was sequenced. Experiments in SPF chickens revealed that the strain is a non-pathogenic virus that did not cause death at challenge doses of 1×106 TCID50. Additionally, the infection in SPF chickens caused no apparent damage in most of the organs analyzed by necropsy and histopathology, but it did cause inclusion body hepatitis; nevertheless it did not generate severe infectious clinical symptoms. The virus was detected in several chicken organs, including the lymphoid organs, by real-time polymerase chain reaction (PCR) until 42 days. The genome of FAdV-11 MX95 has a size of 44,326bp, and it encodes 36 open reading frames (ORFs). Comparative analysis of the genome indicated only 0.8% dissimilarity with a highly virulent serotype 11 that was previously reported.

Comparative metagenomic analysis of PAH degradation in soil by a mixed microbial consortium.

In this study, we used a taxonomic and functional metagenomic approach to analyze some of the effects (e.g. displacement, permanence, disappearance) produced between native microbiota and a previously constructed Polycyclic Aromatic Hydrocarbon (PAH)-degrading microbial consortium during the bioremediation process of a soil polluted with PAHs. Bioaugmentation with a fungal-bacterial consortium and biostimulation of native microbiota using corn stover as texturizer produced appreciable changes in the microbial diversity of polluted soils, shifting native microbial communities in favor of degrading specific populations. Functional metagenomics showed changes in gene abundance suggesting a bias towards aromatic hydrocarbon and intermediary degradation pathways, which greatly favored PAH mineralization. In contrast, pathways favoring the formation of toxic intermediates such as cytochrome P450-mediated reactions were found to be significantly reduced in bioaugmented soils. PAH biodegradation in soil using the microbial consortium was faster and reached higher degradation values (84% after 30 d) as a result of an increased co-metabolic degradation when compared with other mixed microbial consortia. The main differences between inoculated and non-inoculated soils were observed in aromatic ring-hydroxylating dioxygenases, laccase, protocatechuate, salicylate and benzoate-degrading enzyme genes. Based on our results, we propose that several concurrent metabolic pathways are taking place in soils during PAH degradation.

Clinicopathological characterization and genomic sequence differences observed in a highly virulent fowl Aviadenovirus serotype 4.

Highly virulent fowl aviadenoviruses (genus: Aviadenovirus) represent a significant risk in poultry farming that may contribute to increased mortality rates and may adversely affect the growth performance of poultry flocks. In this study, we performed the clinicopathological characterization of a FAdV strain SHP95 isolated from a commercial farm and its whole genome sequencing. The study revealed that the isolated strain is a highly virulent serotype 4 FAdV that can cause 100% mortality in day-old specific pathogen free (SPF) chickens with a dose of 2.5 × 10(5) TCID50. At a lower viral dose (1.5 × 10(4) TCID50), the infection in day-old SPF chickens caused 40% mortality and lesions characteristic for Hepatitis-hydropericardium syndrome (HHS). The viral strain was detectable by real time PCR in chicken organs, including the lymphoid organs until day 28 after infection. The whole genome assembly of strain SHP95 revealed a size of 45,641 bp, which encodes for 42 viral open reading frame (ORF). The comparative analysis in the genome shows 98.1% similarity between strain SHP95 and other FAdV-4 genomes reported. The major differences in the genome sequence between pathogenic and non-pathogenic fowl Adenovirus were identified in the right arm of the genome.

Biodegradation of polycyclic aromatic hydrocarbons by Trichoderma species: a mini review.

Fungi belonging to Trichoderma genus are ascomycetes found in soils worldwide. Trichoderma has been studied in relation to diverse biotechnological applications and are known as successful colonizers of their common habitats. Members of this genus have been well described as effective biocontrol organisms through the production of secondary metabolites with potential applications as new antibiotics. Even though members of Trichoderma are commonly used for the commercial production of lytic enzymes, as a biological control agent, and also in the food industry, their use in xenobiotic biodegradation is limited. Trichoderma stands out as a genus with a great range of substrate utilization, a high production of antimicrobial compounds, and its ability for environmental opportunism. In this review, we focused on the recent advances in the research of Trichoderma species as potent and efficient aromatic hydrocarbon-degrading organisms, as well as aimed to provide insight into its potential role in the bioremediation of soils contaminated with heavy hydrocarbons. Several Trichoderma species are associated with the ability to metabolize a variety of both high and low molecular weight polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, phenanthrene, chrysene, pyrene, and benzo[a]pyrene. PAH-degrading species include Trichoderma hamatum, Trichoderma harzianum, Trichoderma reesei, Trichoderma koningii, Trichoderma viride, Trichoderma virens, and Trichoderma asperellum using alternate enzyme systems commonly seen in other organisms, such as multicooper laccases, peroxidases, and ring-cleavage dioxygenases. Within these species, T. asperellum stands out as a versatile organism with remarkable degrading abilities, high tolerance, and a remarkable potential to be used as a remediation agent in polluted soils.

Morphological changes and growth of filamentous fungi in the presence of high concentrations of PAHs.

In this study, we evaluated the effect of low and high molecular weight polycyclic aromatic hydrocarbons (PAHs), i.e., Phenanthrene, Pyrene and Benzo[a]pyrene, on the radial growth and morphology of the PAH-degrading fungal strains Aspergillus nomius H7 and Trichoderma asperellum H15. The presence of PAHs in solid medium produced significant detrimental effects on the radial growth of A. nomius H7 at 4,000 and 6,000 mg L(-1) and changes in mycelium pigmentation, abundance and sporulation ability at 1,000-6,000 mg L(-1). In contrast, the radial growth of T. asperellum H15 was not affected at any of the doses tested, although sporulation was observed only up to 4,000 mg L(-1) and as with the H7 strain, some visible changes in sporulation patterns and mycelium pigmentation were observed. Our results suggest that fungal strains exposed to high doses of PAHs significantly vary in their growth rates and sporulation characteristics in response to the physiological and defense mechanisms that affect both pigment production and conidiation processes. This finding is relevant for obtaining a better understanding of fungal adaptation in PAH-polluted environments and for developing and implementing adequate strategies for the remediation of contaminated soils.

Morphological changes and growth of filamentous fungi in the presence of high concentrations of PAHs

In this study, we evaluated the effect of low and high molecular weight polycyclic aromatic hydrocarbons (PAHs), i.e., Phenanthrene, Pyrene and Benzo[a]pyrene, on the radial growth and morphology of the PAH-degrading fungal strains Aspergillus nomius H7 and Trichoderma asperellum H15. The presence of PAHs in solid medium produced significant detrimental effects on the radial growth of A. nomius H7 at 4,000 and 6,000 mg L⁻¹ and changes in mycelium pigmentation, abundance and sporulation ability at 1,000–6,000 mg L⁻¹. In contrast, the radial growth of T. asperellum H15 was not affected at any of the doses tested, although sporulation was observed only up to 4,000 mg L⁻¹ and as with the H7 strain, some visible changes in sporulation patterns and mycelium pigmentation were observed. Our results suggest that fungal strains exposed to high doses of PAHs significantly vary in their growth rates and sporulation characteristics in response to the physiological and defense mechanisms that affect both pigment production and conidiation processes. This finding is relevant for obtaining a better understanding of fungal adaptation in PAH-polluted environments and for developing and implementing adequate strategies for the remediation of contaminated soils.

Degradation of polycyclic aromatic hydrocarbons in soil by a tolerant strain of Trichoderma asperellum.

Trichoderma asperellum H15, a previously isolated strain characterized by its high tolerance to low (LMW) and high molecular weight (HMW) PAHs, was tested for its ability to degrade 3-5 ring PAHs (phenanthrene, pyrene, and benzo[a]pyrene) in soil microcosms along with a biostimulation treatment with sugarcane bagasse. T. asperellum H15 rapidly adapted to PAH-contaminated soils, producing more CO2 than uncontaminated microcosms and achieving up to 78 % of phenanthrene degradation in soils contaminated with 1,000 mg Kg(-1) after 14 days. In soils contaminated with 1,000 mg Kg(-1) of a three-PAH mixture, strain H15 was shown to degrade 74 % phenanthrene, 63 % pyrene, and 81 % of benzo[a]pyrene. Fungal catechol 1,2 dioxygenase, laccase, and peroxidase enzyme activities were found to be involved in the degradation of PAHs by T. asperellum. The results demonstrated the potential of T. asperellum H15 to be used in a bioremediation process. This is the first report describing the involvement of T. asperellum in LMW and HMW-PAH degradation in soils. These findings, along with the ability to remove large amounts of PAHs in soil found in the present work provide enough evidence to consider T. asperellum as a promising and efficient PAH-degrading microorganism.

Complete genome analysis of velogenic Newcastle disease virus reference strain "Chimalhuacan": evolution of viral lineages in Mexico.

Newcastle disease virus with velogenic characteristics circulates in the poultry industry in Mexico and various other American countries. In Mexico, vaccine efficacy testing to obtain commercial registration is reliant on a challenge with a velogenic strain known colloquially as Chimalhuacan due to the site where it was isolated. In this paper, we performed a full genome sequencing of the Chimalhuacan strain. The strain belongs to Class II of APMV, particularly genotype V. The viral RNA genome is 15,192 nt in size and contains six genes: 3' NP-P-M-F-HN-L 5'. The 3' leader sequence is 55 nt in size and the 5' trailer sequence 113 nt. The deduced amino acid sequence confirms a velogenic genotype with four basic amino acids at the cleavage site: (112)RRQKR(↓)F(117). In addition, evolutionary relatedness based on the gene sequence of the fusion protein indicates that this strain is the ancestor of the strains currently circulating in Mexico.

Biodegradation of a mixture of PAHs by non-ligninolytic fungal strains isolated from crude oil-contaminated soil.

Nine native non-ligninolytic fungal strains were isolated from Maya crude oil-contaminated soil and selected based on their ability to grow and use crude oil and several polycyclic aromatic hydrocarbons (PAHs) as carbon source, for their application to PAH removal in soil. The fungi were identified by PCR amplification of intergenic transcribed sequences regions and microbiological techniques, and results showed them to be part of the genera Fusarium, Neurospora, Aspergillus, Scedosporium, Penicillium, Neosartorya and Talaromyces. A primary selection of fungi was made in minimal medium plates, considering the tolerance to different concentrations of PAHs for each strain. The radial extension rate exhibited significant differences (p < 0.05) from 200 to 1,000 mg of PAHs mixture l⁻¹. A secondary selection of Aspergillus terreus, Talaromyces spectabilis, and Fusarium sp. was achieved based on their tolerance to 2,000 mg of a mixture of Phenanathrene and Pyrene kg⁻¹ of soil in a solid-state microcosm system for 2 weeks. The percentage of PAH removal obtained by the three strains was approximately 21 % of the mixture.

Complete genome sequence of a velogenic Newcastle disease virus isolated in Mexico.

In Mexico, the number of cases of the highly virulent Newcastle disease virus is increasing. In 2005, an outbreak of Newcastle disease occurred on an egg laying hen farm in the state of Puebla despite vaccination with the LaSota strain. Farmers experienced a major drop in egg production as a consequence of a field challenge virus. In this study, we characterize the virus, APMV1/chicken/Mexico/P05/2005, responsible for the outbreak. The virus is categorized as a velogenic virus with an intracranial pathogenicity index of 1.99 and a chicken embryo mean death time of 36 h. The complete genome length of the virus was sequenced as consisting of 15,192 bp. In addition, phylogenetic analysis classified the virus as a member of the class II, genotype V. The highly pathogenic nature of the virus has been linked to the amino acid sequence at the fusion protein cleavage site, which contains multiple basic amino acids (RRQKR↓F).

Heterologous expression of manganese peroxidase in Aspergillus niger and its effect on phenanthrene removal from soil.

A strain of Aspergillus niger, previously isolated from sugarcane bagasse because of its capacity to degrade phenanthrene in soil by solid culture, was used to express a manganese peroxidase gene (mnp1) from Phanerochaete chrysosporium, aiming at increasing its polycyclic aromatic hydrocarbons degradation capacity. Transformants were selected based on their resistance to hygromycin B and the discoloration induced on Poly R-478 dye by the peroxidase activity. The recombinant A. niger SBC2-T3 strain developed MnP activity and was able to remove 95% of the initial phenanthrene (400 ppm) from a microcosm soil system after 17 days, whereas the wild strain removed 72% under the same conditions. Transformation success was confirmed by PCR amplification using gene-specific primers, and a single fragment (1,348 bp long, as expected) of the recombinant mnp1 was amplified in the DNA from transformants, which was absent from the parental strain.