Contribution of Serendipita indica on growth improvement, antioxidative capacity of Dracocephalum kotschyi, and its resistance against cadmium stress / Contribución de Serendipita indica a la mejora del crecimiento, la capacidad antioxidante de Dracocephalum kotschyi y su resistencia al estrés por cadmio

Cadmium pollution is a severe issue worldwide which causes an elevated concern in agriculture. The utilization of plant–microbial interactions offers a promising approach for the remediation of cadmium-polluted soils. To elucidate the mechanism of Serendipita indica-mediated cadmium stress tolerance, a potting experiment was conducted to study the impact of S. indica on Dracocephalum kotschyi plants grown under different cadmium concentrations (0, 5, 10, and 20 mg/kg). The effects of cadmium and S. indica on plant growth, antioxidant enzyme activities, and accumulation of cadmium were investigated. The results showed that cadmium stress significantly decreases biomass, photosynthetic pigments, and carbohydrate content concomitantly with increasing antioxidant activities, electrolyte leakage, and hydrogen peroxide, proline, and cadmium content. Inoculation with S. indica alleviated the adverse effect of cadmium stress by enhancing shoot and root dry weight, photosynthetic pigments, and carbohydrate, proline, and catalase activity. Unlike cadmium stress, the presence of fungus led to a reduction in electrolyte leakage and hydrogen peroxide content as well as the content of cadmium in D. kotschyi leaf which mitigates cadmium-induced oxidative stress. Our findings demonstrated S. indica inoculation alleviates the adverse effects of cadmium stress in D. kotschyi plants which could prolong their survival under stressful conditions. Due to the importance of D. kotschyi and the effect of biomass increase on the amount of its medicinal substances, exploiting S. indica not only promotes plant growth, but also may be used as a potential eco-friendly method for relieving the phytotoxicity of Cd and remediating Cd-contaminated soil.(AU)

Exploring potential soybean bradyrhizobia from high trehalose-accumulating soybean genotypes for improved symbiotic effectiveness in soybean / Exploración de bradirizobios potenciales de la soja a partir de genotipos de soja con alto contenido de trehalosa para mejorar la eficacia simbiótica en la soja

Drought is the most important factor limiting the activity of rhizobia during N-fixation and plant growth. In the present study, we isolated Bradyrhizobium spp. from root nodules of higher trehalose-accumulating soybean genotypes and examined for moisture stress tolerance on a gradient of polyethylene glycol (PEG 6000) amended in yeast extract mannitol (YEM) broth. In addition, the bradyrhizobial strains were also evaluated for symbiotic effectiveness on soybean. Based on 16S rDNA gene sequences, four bradyrhizobial species were recovered from high trehalose-accumulating genotypes, i.e., two Bradyrhizobium liaoningense strains (accession number KX230053, KX230054) from EC 538828 and PK-472, respectively, one Bradyrhizobium daqingense (accession number KX230052) from PK-472, and one Bradyrhizobium kavangense (accession number MN197775) from Valder genotype having low trehalose. These strains, along with two native strains, viz., Bradyrhizobium japonicum (JF792425), Bradyrhizobium liaoningense (JF792426), and one commercial rhizobium, were studied for nodulation, leghaemoglobin, and N-fixation abilities on soybean under sterilized sand microcosm conditions in a completely randomized design. Among all the strains, D-4A (B. daqingense) followed by D-4B (B. liaoningense) was found to have significantly higher nodulation traits and acetylene reduction assay (ARA) activity when compared to other strains and commercial rhizobia. The bradyrhizobia isolates showed plant growth promotion traits such as indole acetic acid (IAA), exopolysaccharide (EPS), and siderophore production, phosphate-solubilizing potential, and proline accumulation. The novel species B. daqingense was reported for the first time from Indian soil and observed to be a potential candidate strain and should be evaluated for conferring drought tolerance in soybean under simulated stress conditions.(AU)

Microbial interactions in alcoholic beverages / Interacciones microbianas en bebidas alcohólicas

This review examines the different types of interactions between the microorganisms involved in the fermentation processes of alcoholic beverages produced all over the world from cereals or fruit juices. The alcoholic fermentation converting sugars into ethanol is usually carried out by yeasts, mainly Saccharomyces cerevisiae, which can grow directly using fruit sugars, such as those in grapes for wine or apples for cider, or on previously hydrolyzed starch of cereals, such as for beers. Some of these beverages, or the worts obtained from cereals, can be distilled to obtain spirits. Besides S. cerevisiae, all alcoholic beverages can contain other microorganisms and especially in spontaneous fermentation when starter cultures are not used. These other microbes are mostly lactic acid bacteria and other yeasts—the non-Saccharomyces yeasts. The interactions between all these microorganisms are very diverse and complex, as in any natural occurring ecosystem, including food fermentations. To describe them, we have followed a simplified ecological classification of the interactions. The negative ones are amensalism, by which a metabolic product of one species has a negative effect on others, and antagonism, by which one microbe competes directly with others. The positive interactions are commensalism, by which one species has benefits but no apparent effect on others, and synergism, by which there are benefits for all the microbes and also for the final product. The main interactions in alcoholic beverages are between S. cerevisiae and non-Saccharomyces and between yeasts and lactic acid bacteria. These interactions can be related to metabolites produced by fermentation such as ethanol, or to secondary metabolites such as proteinaceous toxins, or are feed-related, either by competition for nutrients or by benefit from released compounds during yeast autolysis...(AU)

Microbiota intestinal y salud / Gut microbes and health

El cuerpo humano está poblado por miríadas de microorganismos en toda su superficie y en las cavidades conectadas con el exterior. Los colonizadores microbianos del intestino (microbiota) son parte funcional y no prescindible del organismo humano: aportan genes (microbioma) y funciones adicionales a los recursos de nuestra especie, y participan en múltiples procesos fisiológicos (desarrollo somático, nutrición, inmunidad, etc.). Algunas enfermedades crónicas no transmisibles de la sociedad desarrollada (atopias, síndrome metabólico, enfermedades inflamatorias, cáncer y algunos trastornos de la conducta) se asocian a disbiosis: pérdida de riqueza de especies en la microbiota intestinal y desviación del entorno microbiano ancestral. Los cambios en la transmisión vertical del microbioma, el uso de antisépticos y antibióticos y los hábitos dietéticos de la sociedad industrializada parecen estar en el origen de la disbiosis. Generar y mantener diversidad en la microbiota es un nuevo objetivo clínico para la promoción de salud y la prevención de enfermedades.(AU)

The human body is populated by myriads of microorganisms throughout its surface and in the cavities connected to the outside. The microbial colonisers of the intestine (microbiota) are a functional and non-expendable part of the human organism: they provide genes (microbiome) and additional functions to the resources of our species and participate in multiple physiological processes (somatic development, nutrition, immunity, etc.). Some chronic non-communicable diseases of developed society (atopias, metabolic syndrome, inflammatory diseases, cancer and some behaviour disorders) are associated with dysbiosis: loss of species richness in the intestinal microbiota and deviation from the ancestral microbial environment. Changes in the vertical transmission of the microbiome, the use of antiseptics and antibiotics, and dietary habits in industrialised society appear to be at the origin of dysbiosis. Generating and maintaining diversity in the microbiota is a new clinical target for health promotion and disease prevention.(AU)

Microbioma humano en la salud y la enfermedad / The human microbiome in sickness and in health

El estudio del microbioma humano ha incrementado de manera excepcional el conocimiento actual del que disponemos sobre la importancia de la microbiota en la salud durante todas las etapas de la vida. La colonización microbiana humana ocurre en la piel, en el sistema genitourinario y, principalmente, en la cavidad oral y el tracto intestinal. En todos estos lugares, la microbiota humana establece una relación simbiótica con el hospedador y ayuda a mantener la homeostasis fisiológica. El estilo de vida, la edad, la dieta y el uso de antibióticos son los principales reguladores de la composición y la funcionalidad de la microbiota humana. Estudios recientes apuntan al descenso de la diversidad microbiana como uno de los aspectos que contribuye al desarrollo de enfermedades. Además de los estudios de diversidad filogenética, es necesario profundizar en estudios metagenómicos a nivel funcional del microbioma humano para mejorar el conocimiento sobre su participación en la salud humana (AU)

The study of the human microbiome has led to an exceptional increase in the current understanding of the importance of microbiota for health throughout all stages of life. Human microbial colonization occurs in the skin, genitourinary system and, mainly, in the oral cavity and intestinal tract. In these locations, the human microbiota establishes a symbiotic relationship with the host and helps maintain the physiological homeostasis. Lifestyle, age, diet and use of antibiotics are the main regulators of the composition and functionality of human microbiota. Recent studies have indicated the reduction in microbial diversity as one of the contributors to the development of diseases. In addition to phylogenetic diversity studies, further metagenomic studies are needed at the functional level of the human microbiome to improve our understanding of its involvement in human health (AU)

Filariasis linfática / Lymphatic filariasis

Las filariasis linfáticas son un grupo de enfermedades causadas por nematodos de la familia Filaroidea que precisan de vectores para su transmisión. El número de infectados se estima en 120 millones a nivel mundial, encontrándose dos tercios de los afectados en Asia. Las manifestaciones clínicas de la enfermedad son variadas (astenia, fiebre, linfedema, etc.) y van a depender de la presencia de gusanos adultos en los vasos linfáticos, la respuesta inmune del huésped y su respuesta endosimbiótica de la bacteria Wolbachia. La confirmación diagnóstica se realiza mediante la detección y visualización de las microfilarias en la sangre o en la piel. El tratamiento farmacológico se basa principalmente en el uso de dietilcarbamazepina. En las especies donde se ha demostrado la presencia de la bacteria endosimbiótica Wolbachia también se recomienda doxiciclina

Lymphatic filariasis is a group of diseases caused by nematodes of the family Filarioidea which require vectors for their transmission. The number of people infected globally is estimated at 120 million, two thirds of which are in Asia. The clinical manifestations of this disease are varied (asthenia, fever, lymphedema, etc.) and will depend on the presence of adult worms in lymph vessels, on the immune response of the host, and on the endosymbiotic response to Wolbachia bacteria. Diagnosis is confirmed by detection and visualization of microfilariae in blood or skin. Drug treatment is mainly based on the use of diethylcarbamazine. Doxycycline is also recommended in species in which the presence of Wolbachia endosymbiotic bacteria has been proven

Re-purposing is needed for beneficial bugs, not for the drugs

Between 150 and 200 species of plants, insects, birds or mammals go extinct every day. We do not have any idea what the global extinction rate for microorganisms is. What is clear is that we have already lost a maximum number of the microbes that used to live in and on our skins. Many of our microbial partners are facing extinction as we apply selection pressures that are unprecedented in our long-standing relationships. Recent estimates are that we have lost at least one third of the diversity of our skin microbiome. Every day, most of us bath or shower in water that contains chlorine or fluorine; these additives do a great job of killing pathogenic microbes, but they are probably not helping our skin microbiome. Most of the people apply cosmetic products every day, as these products contain preservatives that prevent microbial growth on the shelf. These same chemicals may well kill microbes on the skin. The daily use of high-pH soaps probably will not help microbial life that is adapted to living on the skin's natural pH of 5. The rise in the rate of C-section births from around 5% in 1970 to more than 30% today is likely to be a contributing factor. Vaginal microbes seed our skins at birth and C-sections disrupt this process. The overuse of broad-spectrum antibiotics has contributed to the loss of our microbial partners in all body sites and the skin is no exception. It is now clear that skin is an ecosystem that is dependent on commensal microbes for optimal health. In general, a diverse ecosystem is a healthy ecosystem that is robust in the face of change. Low-diversity ecosystems are more fragile and susceptible to dysbiosis. Eczema and acne rates have increased rapidly over the last 50 years. These diseases are almost unknown in hunter-gatherer communities. Now, we face two exciting challenges: finding out which species matter and how to get them back

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Identification of two pesticide-tolerant bacteria isolated from Medicago sativa nodule useful for organic soil phytostabilization

Plant-microbe interactions such as rhizobacteria legumes are interesting in organic farming that has undergone significant expansion in the world. The organic agriculture is as an environment-friendly technique and a sustainable alternative to intensive agricultural system. Three types of soil were chosen, organic (ORG), conventional (CON), and fallow land (NA) to isolate soil bacteria-nodulating Medicago sativa, in order to develop microbial inoculants for use in agricultural sustainable system. Soil analysis revealed significant higher amounts of total nitrogen, organic carbon, total phosphorus, and matter detected in ORG. As for heavy metals, ORG showed high Cu content due to the authorized chemical use in organic farming. A sample of 130 bacteria was isolated from Medicago sativa nodule, genetically characterized by PCR/RFLP of ribosomal 16S RNAs, and a great dominance of Sinorhizobium meliloti (88.4%, 73.8%, and 55.5%) is obtained among NA-, CON-, and ORG-managed soils, respectively. The ORG showed the high bacterial diversity with 13.3% of non-identified strains. The resistance against five pesticides (Prosper, Cuivox, Fungastop, Nimbecidine, and Maneb) revealed a maximum of inhibitory concentration about 10 mg l−1 of Prosper, 12 mg l−1 of Cuivox, 6 ml l−1 of Fungastop, 7.5 ml l−1of Nimbecidine, and 25 ml l−1 of Maneb. The analysis of the symbiotic properties and plant growth-promoting potential revealed two efficient strains significantly increased alfalfa dry weight through producing siderophores, phosphorus, and indole acetic acid (13.6 mg ml−1 and 19.9 mg ml−1 respectively). Hence, we identify two tolerant and efficient strains, Achromobacter spanium and Serratia plymuthica, isolated from Medicago sativa nodule with valuable potential able to phytostabilize pesticide-contaminated soils

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Simbiosis y narcisisimo en la adolescencia. A propósito de un caso / Symbiosis and narcissism in adolescence. About a case / Simbiosi i narcisisme en l'adolescéncia. A propósit d'un cas

Las reflexiones que mostraremos a continuación parten de la experiencia asistencial con un caso asistido por los autores del artículo en co-terapia y de las conversaciones inter-sesión. Una gran parte de las reflexiones sobre el caso las hemos podido hacer a posteriori de la experiencia terapéutica. Nuestro objetivo principal es el cuidado y atención de los menores y sus familias. Escribir este artículo permite la elaboración mental del caso y la función de presentarlo es repensarlo para seguir velando por mejorar la asistencia a la salud mental infantil y juvenil desde nuestra institución

The reflections that we are going to show are based on our care experience in co-therapy and on conversations between sessions. A large part of the case reflections has been made after the therapeutic experience. Our main objective is the care and attention of minors and their families. Writing this article allows the mental elaboration of the case and presenting it aims at reconsidering and making our institution keep on improving the mental health assistance of children and youth

Les reflexions que mostrarem a continuació par­teixen de l'experiéncia assistencial amb un cas assistit pels autors en co-terápia i de les converses inter-sessió. Una gran part de les reflexions sobre el cas les hem pogut fer a posteriori de l’experiència terapèutica. El nostre objectiu principal és la cura i l'atenció dels menors i les seves famílies. Escriure l’article permet l'elaboració men­tal del cas i la funció de presentar-lo és repensar-lo per seguir vetllant per millorar l'assisténcia a la salut mental infantil i juvenil des de la nostra institució

Revisiting the genus Photobacterium: taxonomy, ecology and pathogenesis

The genus Photobacterium, one of the eight genera included in the family Vibrionaceae, contains 27 species with valid names and it has received attention because of the bioluminescence and pathogenesis mechanisms that some of its species exhibit. However, the taxonomy and phylogeny of this genus are not completely elucidated; for example, P. logei and P. fischeri are now considered members of the genus Aliivibrio, and previously were included in the genus Vibrio. In addition, P. damselae subsp. piscicida was formed as a new combination for former Vibrio damsela and Pasteurella piscicida. Moreover, P. damselae subsp. damselae is an earlier heterotypic synonym of P. histaminum. To avoid these incovenences draft and complete genomic sequences of members of Photobacterium are increasingly becoming available and their use is now routine for many research laboratories to address diverse goals: species delineation with overall genomic indexes, phylogenetic analyses, comparative genomics, and phenotypic inference. The habitats and isolation source of the Photobacterium species include seawater, sea sediments, saline lake waters, and a variety of marine organisms with which the photobacteria establish different relationships, from symbiosis to pathogenic interactions. Several species of this genus contain bioluminescent strains in symbiosis with marine fish and cephalopods; in addition, other species enhance its growth at pressures above 1 atmosphere, by means of several high-pressure adaptation mechanisms and for this, they may be considered as piezophilic (former barophilic) bacteria. Until now, only P. jeanii, P. rosenbergii, P. sanctipauli, and the two subspecies of P. damselae have been reported as responsible agents of several pathologies on animal hosts, such as corals, sponges, fish and homeothermic animals. In this review we have revised and updated the taxonomy, ecology and pathogenicity of several members of this genus (AU)

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Functional symbiosis and communication in microbial ecosystems. The case of wood-eating termites and cockroaches

Animal hosts typically have strong specificity for microbial symbionts and their functions. The symbiotic relationships have enhanced the limited metabolic networks of most eukaryotes by contributing several prokaryotic metabolic capabilities, such as methanogenesis, chemolithoautotrophy, nitrogen assimilation, etc. This review will examine the characteristics that determine bacterial «fidelity» to certain groups of animals (e.g., xylophagous insects, such as termites and cockroaches) over generations and throughout evolution. The hindgut bacteria of wood-feeding termites and cockroaches belong to several phyla, including Proteobacteria, especially Deltaproteobacteria, Bacteroidetes, Firmicutes, Actinomycetes, Spirochetes, Verrucomicrobia, and Actinobacteria, as detected by 16S rRNA. Termites effectively feed on many types of lignocelluloses assisted by their gut microbial symbionts. Although the community structures differ between the hosts (termites and cockroaches), with changes in the relative abundances of particular bacterial taxa, the composition of the bacterial community could reflect at least in part the host evolution in that the microbiota may derive from the microbiota of a common ancestor. Therefore, factors other than host phylogeny, such as diet could have had strong influence in shaping the bacterial community structure (AU)

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Autores-revisores y editores, ¿parasitismo o simbiosis? / Authors-reviewers and editors, parasitism or symbiosis?

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Repetición y creación: vida pulsional y narcisismo / Repetition and creation: narcissism and the life of the drivers

A través de un amplio material clínico, postulo que en nuestro trabajo clínico nos confrontamos con situaciones en las que el narcisismo polariza las fuerzas pulsionales, con el riesgo de que al ponerse al servicio de las pulsiones de muerte se produzca una des ligazón y una desinvestidura (del objeto, del analista y del yo). En esa tesitura hemos de tener muy cuenta la transformación que ha de sufrir la investidura narcisista para poder desprender esas fuerzas pulsionales del imperio narcisista. Para desarrollar dicha tesis abordo la regresión narcisista, la sexualización del yo, la escisión entre la corriente de ternura y la corriente de sensualidad y el rol de la escena primaria. Destaco la importancia del trabajo transfero-contratransferencial para desvelar la identificación narcisista y para elaborar el riesgo de desinvestidura y el escepticismo amoroso posibilitando la constitución de un objeto interno confiable. Este artículo trata de integrar el modelo pulsional con el de las relaciones objetales (AU)

The author, through a broad review of the clinical material, suggests that we are faced in our clinical work with situations where narcissism polarizes the driving forces. This runs the risk of narcissism engendering a death-wish-like state that can bring about a "disconnect" and reduced cathexis (for the object of the patient's drives, the analyst and the self). In this context, we need to be acutely aware of the transformation that the narcissistic cathexis undergoes in order to be able to detach these driving forces from the narcissistic domain. To develop this thesis, the author focuses on narcissistic regression, the sexualization of the self, the split between the state of tendernness and the state of sensuality and the role of the primal scene. The author also highlights the importance of the development of transference-counter-transference in revealing narcissistic identification, the risk of reduced cathexis and skeptical love. This may open the way for the constitution of trustworthy internal object. This work seeks to integrate the drive model with the object-relations model (AU)

Succession of the gut microbiota in the cockroach Blattella germanica

The cockroach gut harbors a wide variety of microorganisms that, among other functions, collaborate in digestion and act as a barrier against pathogen colonization. Blattabacterium, a primary endosymbiont, lives in the fat body inside bacteriocytes and plays an important role in nitrogen recycling. Little is known about the mode of acquisition of gut bacteria or their ecological succession throughout the insect life cycle. Here we report on the bacterial taxa isolated from different developmental instars of the cockroach Blattella germanica. The bacterial load in the gut increased two orders of magnitude from the first to the second nymphal stage, coinciding with the incorporation of the majority of bacterial taxa, but remained similar thereafter. Pyrosequencing of the hypervariable regions V1-V3 of the 16S rRNA genes showed that the microbial composition differed significantly between adults and nymphs. Specifically, a succession was observed in which Fusobacterium accumulated with aging, while Bacteroides decreased. Blattabacterium was the only symbiont found in the ootheca, which makes the vertical transmission of gut bacteria an unlikely mode of acquisition. Scanning electron microscopy disclosed a rich bacterial biofilm in third instar nymphs, while filamentous structures were found exclusively in adults (AU)

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Homosexualidades / Homosexualities

Para referirse a las homosexualidades, el autor parte de una metapsicología freudiana. Define una línea evolutiva: en el extremo izquierdo, ubica funcionamientos relacionados con una simbiosis e indiferenciación con respecto al objeto primario; en el derecho, funcionamientos neuróticos estructurados en torno a la represión. Se centra en cuatro puntos paradigmáticos de la línea para estudiarlos más en profundidad. Presenta material clínico de dos casos: uno de una mujer con una parte importante de su psiquismo organizado en torno a la represión y por ello fundamentalmente neurótica; otro de un hombre con importantes dificultades para diferenciarse de una mamma-donna, que tardíamente debuta con un funcionamiento homosexual. Entra en cuestiones polémicas como la homoparentalidad y la posibilidad de que pueda haber psicoanalistas homosexuales, denunciando la tendencia a homogenizar el pensamiento sobre todas las homosexualidades según el sesgo ideológico de cada autor, y abogando por el estudio de la singularidad de cada caso (AU)

In order to study homosexualities, the author takes the freudian metapsychology as a starting point. He describes an evolutionary straight line: on the left side of the line, he places psychic ways of working related to a symbiosis or lack of differentiation from the primary object; on the right side of the line, he places neurotic ways of working organized by the depression. He draws attention on four paradigmatic points of the line in order to study them more deeply. He presents clinincal material related to two cases: the first one is about a woman with an important part of her psyche organized by te repression and thus, essentially neurotic; the other case history deals with a man with important problems to differentiate himself from a mamma-donna, who makes his debut with a late onset homosexuality. The author assesses controversial questions questions such as homparentality and the possible option for homosexual to become psychoanalysts. He criiticizes the tendency of each author to homogenize the issu of all kinds of homosexualities depending on his ideological bias. He recommends the singular study of each individual case (AU)

Symbiogenesis: the holobiont as a unit of evolution

Symbiogenesis is the result of the permanent coexistence of various bionts to form the holobiont (namely, the host and its microbiota). The holobiome is the sum total of the component genomes in a eukaryotic organism; it comprises the genome of an individual member of a given taxon (the host genome) and the microbiome (the genomes of the symbiotic microbiota). The latter is made up of the genes of a variety of microbial communities that persist over time and are not eliminated by natural selection. Therefore, the holobiome can also be considered as the genomic reflection of the complex network of symbiotic interactions that link an individual member of a given taxon with its associated microbiome. Eukaryotic individuals can be analyzed as coevolved, tightly integrated, prokaryotic communities; in this view, natural selection acts on the holobiont as if it were an integrated unit. The best studied holobionts are those that emerged from symbioses involving insects. The presence of symbiotic associations throughout most of the evolutionary history of insects suggests that they were a driving force in the diversification of this group. Support for the evolutionary importance of symbiogenesis comes from the observation that the gradual passage from an ancestral to a descendant species by the accumulation of random mutations has not been demonstrated in the field, nor in the laboratory, nor in the fossil record. Instead, symbiogenesis expands the view of the point-mutation-only as the unique mechanisms of evolution and offers an explanation for the discontinuities in the fossil record («punctuated equilibrium»). As such, it challenges conventional paradigms in biology. This review describes the relationships between xylophagous insects and their microbiota in an attempt to understand the characteristics that have determined bacterial fidelity over generations and throughout evolutionary history (AU)

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The contribution of Trichoderma to balancing the costs of plant growth and defense

Trichoderma is a fungal genus of cosmopolitan distribution and high biotechnological value, with several species currently used as biological control agents. Additionally, the enzyme systems of the fungus are widely applied in industry. Species of Trichoderma protect plants against the attack of soil-borne plant pathogens by competing for nutrients and inhibiting or killing plant pathogenic fungi and oomycetes, through the production of antibiotics and/or hydrolytic enzymes. In addition to the role of Trichoderma spp. as biocontrol agents, they have other beneficial effects on plants, including the stimulation of plant defenses and the promotion of plant growth. In this review, we focus on the complex plant defense signaling network that allows the recognition of fungi as non-hostile microbes, including microbial-associated molecular patterns (MAMPs), damage associated molecular patterns (DAMPs) and secreted elicitors. We also examine how fungal interactions with plant receptors can activate induced resistance by priming and balancing plant defense and growth responses. Our observations are integrated into a model describing Trichoderma-plant hormone signaling network interactions (AU)

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Progreso en el conocimiento de la microbiota intestinal humana / Progress in the knowledge of the intestinal human microbiota

La aparición de nuevas técnicas de secuenciación así como el desarrollo de herramientas bioinformáticas han permitido no sólo describir la composición de la comunidad bacteriana que habita el tracto gastrointestinal, sino también las funciones metabólicas de las que proveen al huésped. La mayoría de los miembros de esta amplia comunidad bacteriana pertenecen a Dominio Bacteria, aunque encontramos también Archaea y formas eucariotas y virus. Únicamente entre 7 y 9 de las 55 Phyla del Dominio Bacteria conocidos están presentes en flora fecal humana. Su mayoría pertenecen además a las Divisiones Bacteroidetes and Firmicutes, encontrando también Proteobacteria, Actinobacteria, Fusobacteria y Verrucomicrobia. Bacteroides, Faecalibacterium y Bifidobacterium son los Géneros más abundantes aunque su abundancia relativa es muy variable entre individuos. El análisis metagenómico de la flora intestinal ha permitido describir una colección de 5 millones de genes microbianos que codifican para aproximadamente 20.000 funciones biológicas relacionadas con la vida de las bacterias. El ecosistema intestinal humano puede clasificarse en torno a tres grupos de acuerdo a la abundancia relativa de tres Géneros: Bacteroides (enterotipo 1), Prevotella (enterotipo 2) y Ruminococcus (enterotype 3). Estos grupos han sido denominados «enterotipos» y su descripción sugiere que las variaciones entre individuos están estratificadas. Una vez descrita la composición bacteriana sería interesante establecer la relación entre la alteración de equilibrios ecológicos con estados de enfermedad que puedan desembocar en una novedosa vía terapéutica (AU)

New sequencing technologies together with the development of bio-informatics allow a description of the full spectrum of the microbial communities that inhabit the human intestinal tract, as well as their functional contributions to host health. Most community members belong to the domain Bacteria, but Archaea, Eukaryotes (yeasts and protists), and Viruses are also present. Only 7 to 9 of the 55 known divisions or phyla of the domain Bacteria are detected in faecal or mucosal samples from the human gut. Most taxa belong to just two divisions: Bacteroidetes and Firmicutes, and the other divisions that have been consistently found are Proteobacteria, Actinobacteria, Fusobacteria, and Verrucomicrobia. Bacteroides, Faecalibacterium and Bifidobacterium are the most abundant genera but their relative proportion is highly variable across individuals. Full metagenomic analysis has identified more than 5 million non-redundant microbial genes encoding up to 20,000 biological functions related with life in the intestinal habitat. The overall structure of predominant genera in the human gut can be assigned into three robust clusters, which are known as "enterotypes". Each of the three enterotypes is identifiable by the levels of one of three genera: Bacteroides (enterotype 1), Prevotella (enterotype 2) and Ruminococcus (enterotype 3). This suggests that microbiota variations across individuals are stratified, not continuous. Next steps include the identification of changes that may play a role in certain disease states. A better knowledge of the contributions of microbial symbionts to host health will help in the design of interventions to improve symbiosis and combat disease (AU)

Association between Pseudonocardia symbionts and Atta leaf-cutting ants suggested by improved isolation methods

Fungus-growing ants associate with multiple symbiotic microbes, including Actinobacteria for production of antibiotics. The best studied of these bacteria are within the genus Pseudonocardia, which in most fungus-growing ants are conspicuously visible on the external cuticle of workers. However, given that fungus-growing ants in the genus Atta do not carry visible Actinobacteria on their cuticle, it is unclear if this genus engages in the symbiosis with Pseudonocardia. Here we explore whether improving culturing techniques can allow for successful isolation of Pseudonocardia from Atta cephalotes leaf-cutting ants. We obtained Pseudonocardia from 9 of 11 isolation method/colony component combinations from all 5 colonies intensively sampled. The most efficient technique was bead-beating workers in phosphate buffer solution, then plating the suspension on carboxymethylcellulose medium. Placing these strains in a fungus-growing ant-associated Pseudonocardia phylogeny revealed that while some strains grouped with clades of Pseudonocardia associated with other genera of fungus-growing ants, a large portion of the isolates fell into two novel phylogenetic clades previously not identified from this ant-microbe symbiosis. Our findings suggest that Pseudonocardia may be associated with Atta fungus-growing ants, potentially internalized, and that localizing the symbiont and exploring its role is necessary to shed further light on the association (AU)

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