The Evolution of Interdependence in a Four-Way Mealybug Symbiosis.

Mealybugs are insects that maintain intracellular bacterial symbionts to supplement their nutrient-poor plant sap diets. Some mealybugs have a single betaproteobacterial endosymbiont, a Candidatus Tremblaya species (hereafter Tremblaya) that alone provides the insect with its required nutrients. Other mealybugs have two nutritional endosymbionts that together provision these same nutrients, where Tremblaya has gained a gammaproteobacterial partner that resides in its cytoplasm. Previous work had established that Pseudococcus longispinus mealybugs maintain not one but two species of gammaproteobacterial endosymbionts along with Tremblaya. Preliminary genomic analyses suggested that these two gammaproteobacterial endosymbionts have large genomes with features consistent with a relatively recent origin as insect endosymbionts, but the patterns of genomic complementarity between members of the symbiosis and their relative cellular locations were unknown. Here, using long-read sequencing and various types of microscopy, we show that the two gammaproteobacterial symbionts of P. longispinus are mixed together within Tremblaya cells, and that their genomes are somewhat reduced in size compared with their closest nonendosymbiotic relatives. Both gammaproteobacterial genomes contain thousands of pseudogenes, consistent with a relatively recent shift from a free-living to an endosymbiotic lifestyle. Biosynthetic pathways of key metabolites are partitioned in complex interdependent patterns among the two gammaproteobacterial genomes, the Tremblaya genome, and horizontally acquired bacterial genes that are encoded on the mealybug nuclear genome. Although these two gammaproteobacterial endosymbionts have been acquired recently in evolutionary time, they have already evolved codependencies with each other, Tremblaya, and their insect host.

Distribution of the obligate endosymbiont Blochmannia floridanus and expression analysis of putative immune genes in ovaries of the carpenter ant Camponotus floridanus.

The bacterial endosymbiont Blochmannia floridanus of the carpenter ant Camponotus floridanus contributes to its hosts' ontogeny via nutritional upgrading during metamorphosis. This primary endosymbiosis is essential for both partners and vertical transmission of the endosymbionts is guaranteed by bacterial infestation of oocytes. Here we present a detailed analysis of the presence and localisation of B. floridanus in the ants' ovaries obtained by FISH and TEM analyses. The most apical part of the germarium harbouring germ-line stem cells (GSCs) is not infected by the bacteria. The bacteria are detectable for the first time in lower parts of the germarium when cystocytes undergo the 4th and 5th division and B. floridanus infects somatic cells lying under the basal lamina surrounding the ovarioles. With the beginning of cystocyte differentiation, the endosymbionts are exclusively transported from follicle cells into the growing oocytes. This infestation of the oocytes by bacteria very likely involves exocytosis-endocytosis processes between follicle cells and the oocytes. Nurse cells were never found to harbour the endosymbionts. Furthermore we present first gene expression data in C. floridanus ovaries. These data indicate a modulation of immune gene expression which may facilitate tolerance towards the endosymbionts and thus may contribute to their transovarial transmission.

Scrutinizing the immune defence inventory of Camponotus floridanus applying total transcriptome sequencing.

BACKGROUND: Defence mechanisms of organisms are shaped by their lifestyle, environment and pathogen pressure. Carpenter ants are social insects which live in huge colonies comprising genetically closely related individuals in high densities within nests. This lifestyle potentially facilitates the rapid spread of pathogens between individuals. In concert with their innate immune system, social insects may apply external immune defences to manipulate the microbial community among individuals and within nests. Additionally, carpenter ants carry a mutualistic intracellular and obligate endosymbiotic bacterium, possibly maintained and regulated by the innate immune system. Thus, different selective forces could shape internal immune defences of Camponotus floridanus. RESULTS: The immune gene repertoire of C. floridanus was investigated by re-evaluating its genome sequence combined with a full transcriptome analysis of immune challenged and control animals using Illumina sequencing. The genome was re-annotated by mapping transcriptome reads and masking repeats. A total of 978 protein sequences were characterised further by annotating functional domains, leading to a change in their original annotation regarding function and domain composition in about 8% of all proteins. Based on homology analysis with key components of major immune pathways of insects, the C. floridanus immune-related genes were compared to those of Drosophila melanogaster, Apis mellifera, and other hymenoptera. This analysis revealed that overall the immune system of carpenter ants comprises many components found in these insects. In addition, several C. floridanus specific genes of yet unknown functions but which are strongly induced after immune challenge were discovered. In contrast to solitary insects like Drosophila or the hymenopteran Nasonia vitripennis, the number of genes encoding pattern recognition receptors specific for bacterial peptidoglycan (PGN) and a variety of known antimicrobial peptide (AMP) genes is lower in C. floridanus. The comparative analysis of gene expression post immune-challenge in different developmental stages of C. floridanus suggests a stronger induction of immune gene expression in larvae in comparison to adults. CONCLUSIONS: The comparison of the immune system of C. floridanus with that of other insects revealed the presence of a broad immune repertoire. However, the relatively low number of PGN recognition proteins and AMPs, the identification of Camponotus specific putative immune genes, and stage specific differences in immune gene regulation reflects Camponotus specific evolution including adaptations to its lifestyle.

Versatile roles of the chaperonin GroEL in microorganism-insect interactions.

The chaperonin 60 (Cpn60) is present in all three kingdoms of life and is one of the most conserved proteins in living organisms. The Escherichia coli Cpn60 (GroEL) is the best studied representative of the huge Cpn60 family. It is an essential protein because in conjunction with the chaperonin 10 (Cpn10 or GroES) it forms a protein-folding machine required for correct folding of many proteins and for recycling of misfolded proteins. As many other chaperones, GroEL and GroES are also known as heat-shock proteins (HSPs), since heat stress leads to a strong induction of their expression, a measure to counteract the increase in misfolded proteins as a result of a high nonphysiological temperature. A large amount of literature is available which is dedicated to the elucidation of how protein folding is assisted by this molecular chaperone. However, apart from this primary task, additional so-called 'moonlighting' functions of GroEL proteins unrelated to their folding activity have emerged in the past years. In fact, it becomes apparent that GroEL proteins have diverse functions in particular in mutualistic and pathogenic microorganism-host interactions. In this brief review, we describe some of these recent findings focusing on the importance of GroEL for microorganism-insect interactions.

Molecular characterization of antimicrobial peptide genes of the carpenter ant Camponotus floridanus.

The production of antimicrobial peptides (AMPs) is a major defense mechanism against pathogen infestation and of particular importance for insects relying exclusively on an innate immune system. Here, we report on the characterization of three AMPs from the carpenter ant Camponotus floridanus. Due to sequence similarities and amino acid composition these peptides can be classified into the cysteine-rich (e.g. defensin) and glycine-rich (e.g. hymenoptaecin) AMP groups, respectively. The gene and cDNA sequences of these AMPs were established and their expression was shown to be induced by microbial challenge. We characterized two different defensin genes. The defensin-2 gene has a single intron, whereas the defensin-1 gene has two introns. The deduced amino acid sequence of the C. floridanus defensins is very similar to other known ant defensins with the exception of a short C-terminal extension of defensin-1. The hymenoptaecin gene has a single intron and a very peculiar domain structure. The corresponding precursor protein consists of a signal- and a pro-sequence followed by a hymenoptaecin-like domain and six directly repeated hymenoptaecin domains. Each of the hymenoptaecin domains is flanked by an EAEP-spacer sequence and a RR-site known to be a proteolytic processing site. Thus, proteolytic processing of the multipeptide precursor may generate several mature AMPs leading to an amplification of the immune response. Bioinformatical analyses revealed the presence of hymenoptaecin genes with similar multipeptide precursor structure in genomes of other ant species suggesting an evolutionary conserved important role of this gene in ant immunity.

Predictive value of clinical risk indicators in child development: final results of a study based on psychoanalytic theory / Valor preditivo de indicadores clínicos de risco para o desenvolvimento infantil: um estudo a partir da teoria psicanalítica

We present the final results of a study using the IRDI (Clinical Risk Indicators in child Development). Based on a psychoanalytic approach, 31 risk signs for child development were constructed and applied to 726 children between the ages of 0 and 18 months. One sub-sample was evaluated at the age of three. The results showed a predictive capacity of IRDIs to indicate developmental problems; 15 indicators for the IRDI were also highlighted that predict psychic risk for the constitution of the subject.AU

No presente artigo, apresentam-se os resultados finais da Pesquisa IRFI. A partir da psicanálise, 31 indicadores clínicos de risco para o desenvolvimento infantil (IRDI) foram construídos e aplicados em 726 crianças entre 0 e 18 meses. Uma sub-amostra foi avaliada com a idade de 3 anos. Os resultados apontaram a capacidade dos IRDI para predizer problemas de desenvolvimento e destacaram ainda 15 indicadores do IRDI com capacidade para predizer risco psíquico para a constituição subjetiva.AU

El presente artículo presenta los resultados finales de la pesquisa IRDI. Desde el psicoanálisis, 31 signos de riesgo para el desarrollo infantil (IRDI) se han construido y aplicado a 726 niños entre 0 y 18 meses. Se evaluó una sub nuestra a los 3 años de edad. Los resultados muestran que los IRDI poseen una capacidad de predecir problemas de desarrollo 15 signos muestran una capacidad de predicción de riesgo psíquico para la constitución subjetiva.AU

Predictive value of clinical risk indicators in child development: final results of a study based on psychoanalytic theory / Valor preditivo de indicadores clínicos de risco para o desenvolvimento infantil: um estudo a partir da teoria psicanalítica / Valor predictivo de indicadores clínicos de riesgo para el desarrollo infantil: un estudio a partir de la teoría psicoanalítica / Valeur prédictive d'indicateurs cliniques de risque pour le développement de l'enfant: une étude à partir de la théorie psychanalytique

We present the final results of a study using the IRDI (Clinical Risk Indicators in child Development). Based on a psychoanalytic approach, 31 risk signs for child development were constructed and applied to 726 children between the ages of 0 and 18 months. One sub-sample was evaluated at the age of three. The results showed a predictive capacity of IRDIs to indicate developmental problems; 15 indicators for the IRDI were also highlighted that predict psychic risk for the constitution of the subject.

No presente artigo, apresentam-se os resultados finais da Pesquisa IRFI. A partir da psicanálise, 31 indicadores clínicos de risco para o desenvolvimento infantil (IRDI) foram construídos e aplicados em 726 crianças entre 0 e 18 meses. Uma sub-amostra foi avaliada com a idade de 3 anos. Os resultados apontaram a capacidade dos IRDI para predizer problemas de desenvolvimento e destacaram ainda 15 indicadores do IRDI com capacidade para predizer risco psíquico para a constituição subjetiva.

El presente artículo presenta los resultados finales de la pesquisa IRDI. Desde el psicoanálisis, 31 signos de riesgo para el desarrollo infantil (IRDI) se han construido y aplicado a 726 niños entre 0 y 18 meses. Se evaluó una sub nuestra a los 3 años de edad. Los resultados muestran que los IRDI poseen una capacidad de predecir problemas de desarrollo 15 signos muestran una capacidad de predicción de riesgo psíquico para la constitución subjetiva.

Cet article présente les résultats de la recherche IRDI. A partir de la psychanalyse, 31 signes cliniques de risque pour le développement de l´enfant (IRDI) ont été développés et appliqués à 726 enfants à l'âge entre 0 et 18 mois. Un sous-échantillon a été évalué à l´âge de trois ans. Les résultats ont montré que les IRDI ont la capacité de prédire des problèmes de développement. Un groupe de 15 signes prévoit d'ailleurs le risque psychique de la constitution subjective.