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Obesity in childhood and adolescence is considered the most prevalent nutritional disorder, in which eating behaviours represent one important factors of influence. Many aspects influence eating behaviours, but taste is considered the main predictor. However, data concerning correlations of obesity, taste sensitivity and behavioural attitudes, such as food neophobia, in children and adolescents are inconsistent. Moreover, it has been suggested that oral bacteria could have a possible role in obesity development and, also, in taste perception. In this context, the present study focused on host related factors with a proposed link to weight gain. To this purpose, taste sensitivity, salivary microbiota composition and food neophobia were compared between children and adolescents with and without obesity in a cross-sectional study. Results showed that children with obesity presented a significantly lower ability in correctly identifying taste qualities and were characterized by a lesser number of Fungiform Papillae (reported as FP/cm2) compared to normal-weight subjects. Differences in the ecological indexes of microbial alpha-diversity was found between subjects with obesity and normal-weight ones. Moreover, independently from nutritional status, some bacterial genera seemed to differ between subjects with different sensitivity. The potentiality of this multidisciplinary approach could help to better understand and deepen the sensory-driven and microbiological factors related to weight gain., Competing Interests: The authors have declared that no competing interests exist.

The Cryptocephalus marginellus (Coleoptera: Chrysomelidae) complex is composed by six species that are supposed to have originated by events of allo- or parapatric speciation. In the present study we investigated the alternative hypotheses that the bacterial communities associated with six populations of this species complex are shaped by environmental factors, or reflect the proposed pattern of speciation. The microbiota associated with the six populations, from five species of the complex, have been characterized through 16S rRNA pyrotag sequencing. Based on a 97% sequence similarity threshold, data were clustered into 381 OTUs, which were analyzed using a variety of diversity indices. The microbiota of C. acquitanus and C. marginellus (Calanques) were the most diverse (over 100 OTUs), while that from C. zoiai yielded less bacterial diversity (45 OTUs). Taxonomic assignment revealed Proteobacteria, Tenericutes and Firmicutes as the dominant components of these beetles' microbiota. The most abundant genera were Ralstonia, Sphingomonas, Rickettsia, and Pseudomonas. Different strains of Rickettsia were detected in C. eridani and C. renatae. The analysis of β-diversity revealed high OTU turnover among the populations of C. marginellus complex, with only few shared species. Hierarchical clustering taking into account relative abundances of OTUs does not match the phylogeny of the beetles, therefore we hypothesize that factors other than phylogenetic constraints play a role in shaping the insects' microbiota. Environmental factors that could potentially affect the composition of bacterial communities were tested by fitting them on the results of a multi-dimensional scaling analysis. No significant correlations were observed towards the geographic distances or the host plants, while the composition of the microbiota appeared associated with altitude. The metabolic profiles of the microbiotas associated with each population were inferred from bacterial taxonomy, and interestingly, the obtained clustering pattern was consistent with the host phylogeny., (© 2014 Institute of Zoology, Chinese Academy of Sciences.)

Bacteriology has embraced the next-generation sequencing revolution, swiftly moving from the time of single genome sequencing to the age of genomic epidemiology. Hundreds and now even thousands of genomes are being sequenced for single bacterial species, allowing unprecedented levels of resolution and insight in the evolution and epidemic diffusion of the main bacterial pathogens. Here, we present a review of some of the most recent and groundbreaking studies in this field.

The ancestors of mitochondria, or proto-mitochondria, played a crucial role in the evolution of eukaryotic cells and derived from symbiotic α-proteobacteria which merged with other microorganisms - the basis of the widely accepted endosymbiotic theory. However, the identity and relatives of proto-mitochondria remain elusive. Here we show that methylotrophic α-proteobacteria could be the closest living models for mitochondrial ancestors. We reached this conclusion after reconstructing the possible evolutionary pathways of the bioenergy systems of proto-mitochondria with a genomic survey of extant α-proteobacteria. Results obtained with complementary molecular and genetic analyses of diverse bioenergetic proteins converge in indicating the pathway stemming from methylotrophic bacteria as the most probable route of mitochondrial evolution. Contrary to other α-proteobacteria, methylotrophs show transition forms for the bioenergetic systems analysed. Our approach of focusing on these bioenergetic systems overcomes the phylogenetic impasse that has previously complicated the search for mitochondrial ancestors. Moreover, our results provide a new perspective for experimentally re-evolving mitochondria from extant bacteria and in the future produce synthetic mitochondria.

Symbiosis is a widespread biological phenomenon, and is particularly common in arthropods. Bloodsucking insects are among the organisms that rely on beneficial bacterial symbionts to complement their unbalanced diet. This review is focused on describing symbiosis, and possible strategies for the symbiont-based control of insects and insect-borne diseases, in three bloodsucking insects of medical importance: the flies of the genus Glossina, the lice of the genus Pediculus, and triatomine bugs of the subfamily Triatominae. Glossina flies are vector of Trypanosoma brucei, the causative agent of sleeping sickness and other pathologies. They are also associated with two distinct bacterial symbionts, the primary symbiont Wigglesworthia spp., and the secondary, culturable symbiont Sodalis glossinidius. The primary symbiont of human lice, Riesia pediculicola, has been shown to be fundamental for the host, due to its capacity to synthesize B-group vitamins. An antisymbiotic approach, with antibiotic treatment targeted on the lice symbionts, could represent an alternative strategy to control these ectoparasites. In the case of triatominae bugs, the genetic modification of their symbiotic Rhodococcus bacteria, for production of anti-Trypanosoma molecules, is an example of paratransgenesis, i.e. the use of symbiotic microorganism engineered in order to reduce the vector competence of the insect host.

Universal bacterial primers are often used in PCR-coupled sequencing approaches to investigate environmental and host-associated bacterial communities. Some of these primers can also amplify eukaryotic DNA. This is leading to the submission of datasets to public databases which are erroneously annotated as prokaryotic sequences. The present note sends a message about the risk of submitting incorrectly annotated sequence data and suggests a reliable approach for the sequencing of 16S rRNA genes and identification of bacteria within complex communities., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Here, we show that an alpha-proteobacterium of the genus Asaia is stably associated with larvae and adults of Anopheles stephensi, an important mosquito vector of Plasmodium vivax, a main malaria agent in Asia. Asaia bacteria dominate mosquito-associated microbiota, as shown by 16S rRNA gene abundance, quantitative PCR, transmission electron microscopy and in situ-hybridization of 16S rRNA genes. In adult mosquitoes, Asaia sp. is present in high population density in the female gut and in the male reproductive tract. Asaia sp. from An. stephensi has been cultured in cell-free media and then transformed with foreign DNA. A green fluorescent protein-tagged Asaia sp. strain effectively lodged in the female gut and salivary glands, sites that are crucial for Plasmodium sp. development and transmission. The larval gut and the male reproductive system were also colonized by the transformed Asaia sp. strain. As an efficient inducible colonizer of mosquitoes that transmit Plasmodium sp., Asaia sp. may be a candidate for malaria control.

During 2021, we collected blood and serum samples from 135 persons exposed to tick bites in southern Italy. We serologically and molecularly screened for zoonotic tickborne pathogens and only molecularly screened for Candidatus Midichloria mitochondrii. Overall, 62 (45.9%) persons tested positive for tickborne pathogens. Coxiella burnetii was detected most frequently (27.4%), along with Rickettsia spp. (21.5%) and Borrelia spp. (10.4%). We detected Candidatus M. mitochondrii DNA in 46 (34.1%) participants who had statistically significant associations to tickborne pathogens (p<0.0001). Phylogenetic analysis of Candidatus M. mitochondrii sequences revealed 5 clades and 8 human sequence types that correlated with vertebrates, Ixodes spp. ticks, and countries in Europe. These data demonstrated a high circulation of tickborne pathogens and Candidatus M. mitochondrii DNA in persons participating in outdoor activities in southern Italy. Our study shows how coordinated surveillance among patients, clinicians, and veterinarians could inform a One Health approach for monitoring and controlling the circulation of tickborne pathogens. [ABSTRACT FROM AUTHOR]

Summary: Phytophagous stink bugs typically harbor nutritional symbiotic bacteria in their midgut, to integrate their unbalanced diet. In the Pentatomidae, most symbionts are affiliated to the genus Pantoea, and are polyphyletic. This suggests a scenario of an ancestral establishment of symbiosis, followed by multiple symbiont replacement events by akin environmental bacteria in different host lineages. In this study, a novel Pantoeaspecies ('CandidatusPantoea persica') was characterized from the gut of the pentatomid Acrosternum arabicum, and shown to be highly abundant in a specific portion of the gut and necessary for the host development. The genome of the symbiont (2.9 Mb), while presenting putative host‐supportive metabolic pathways, including those for amino acids and vitamin synthesis, showed a high level of pseudogenization, indicating ongoing genome reduction. Comparative analyses with other free‐living and symbiotic Pantoea highlighted a convergent pattern of genome reduction in symbionts of pentatomids, putatively following the typical phases modelized in obligate nutritional symbionts of insects. Additionally, this system has distinctive traits, as hosts are closely related, and symbionts originated multiple independent times from closely related free‐living bacteria, displaying convergent and independent conspicuous genome reduction. Due to such peculiarities, this may become an ideal model to study genome evolutionary processes in insect symbionts. [ABSTRACT FROM AUTHOR]

Microorganisms establish with their animal hosts close interactions. They are involved in many aspects of the host life, physiology and evolution, including nutrition, reproduction, immune homeostasis, defence and speciation. Thus, the manipulation and the exploitation the microbiota could result in important practical applications for the development of strategies for the management of insect-related problems. This approach, defined as 'Microbial Resource Management' (MRM), has been applied successfully in various environments and ecosystems, as wastewater treatments, prebiotics in humans, anaerobic digestion and so on. MRM foresees the proper management of the microbial resource present in a given ecosystem in order to solve practical problems through the use of microorganisms. In this review we present an interesting field for application for MRM concept, i.e. the microbial communities associated with arthropods and nematodes. Several examples related to this field of applications are presented. Insect microbiota can be manipulated: (i) to control insect pests for agriculture; (ii) to control pathogens transmitted by insects to humans, animals and plants; (iii) to protect beneficial insects from diseases and stresses. Besides, we prospect further studies aimed to verify, improve and apply MRM by using the insect-symbiont ecosystem as a model. [ABSTRACT FROM AUTHOR]

Background: In recent years, acetic acid bacteria have been shown to be frequently associated with insects, but knowledge on their biological role in the arthropod host is limited. The discovery that acetic acid bacteria of the genus Asaia are a main component of the microbiota of Anopheles stephensi makes this mosquito a useful model for studies on this novel group of symbionts. Here we present experimental results that provide a first evidence for a beneficial role of Asaia in An. stephensi. Results: Larvae of An. stephensi at different stages were treated with rifampicin, an antibiotic effective on wild-type Asaia spp., and the effects on the larval development were evaluated. Larvae treated with the antibiotic showed a delay in the development and an asynchrony in the appearance of later instars. In larvae treated with rifampicin, but supplemented with a rifampicin-resistant mutant strain of Asaia, larval development was comparable to that of control larvae not exposed to the antibiotic. Analysis of the bacterial diversity of the three mosquito populations confirmed that the level of Asaia was strongly decreased in the antibiotic-treated larvae, since the symbiont was not detectable by PCR-DGGE (denaturing gradient gel electrophoresis), while Asaia was consistently found in insects supplemented with rifampicin plus the antibiotic-resistant mutant in the diet, and in those not exposed to the antibiotic. Conclusions: The results here reported indicate that Asaia symbionts play a beneficial role in the normal development of An. stephensi larvae [ABSTRACT FROM AUTHOR]

While symbiosis between bacteria and insects has been thoroughly investigated in the last two decades, investments on the study of yeasts associated with insects have been limited. Insect-associated yeasts are placed on different branches of the phylogenetic tree of fungi, indicating that these associations evolved independently on several occasions. Isolation of yeasts is frequently reported from insect habitats, and in some cases yeasts have been detected in the insect gut and in other organs/tissues. Here we show that the yeast Wickerhamomyces anomalus, previously known as Pichia anomala, is stably associated with the mosquito Anopheles stephensi, a main vector of malaria in Asia. Wickerhamomyces anomalus colonized pre-adult stages (larvae L-L and pupae) and adults of different sex and age and could be isolated in pure culture. By a combination of transmission electron microscopy and fluorescent in situ hybridization techniques, W. anomalus was shown to localize in the midgut and in both the male and female reproductive systems, suggesting multiple transmission patterns. [ABSTRACT FROM AUTHOR]

Candidatus Midichloria mitochondrii ( M. mitochondrii) belongs to a novel clade of bacteria within the order Rickettsiales. Recent PCR-based screening studies indicate that it is present in a number of blood-sucking arthropods, as well as the blood of some vertebrates. Its medical and veterinary significance remains to be determined. Electron microscopic examinations of M. mitochondrii have thus far been conducted on two infected tick species. Remarkably, the bacterium was found in abundance within the mitochondria of the ovarian cells of each tick species. This makes it the only characterized bacterium able to invade the mitochondria of any multicellular organism. To examine whether mitochondrial invasion is a consistent characteristic of M. mitochondrii, we examined two tick species found in Eastern Australia. One of these species, Ixodes holocyclus, was infected with two M. mitochondrii strains; however, no bacteria were seen in the mitochondria. Comparative studies involving these strains may shed light on the unique phenomenon of mitochondrial invasion. [ABSTRACT FROM AUTHOR]

The article reports on the nature of filarial nematodes as crucial helminth parasites of the tropics and leading contribution to global disability. Such nematodes has tendencies to depend upon a symbiotic intracellular bacterium, Wolbachia. This bacterium is important for the development and fertility.

An intracellular bacterium from Ixodes ricinus ticks collected in Italy was characterized by electron microscopy (EM), PCR sequencing of the 16S rRNA gene, molecular phylogenetic analysis, and in situ hybridization (ISH). This bacterium was shown by EM to be present in the cytoplasm, as well as in the mitochondria of ovarian cells. When universal 16S rRNA bacterial primers were used, PCR amplification of ovarian DNA followed by cloning and sequencing resulted in the same sequence being found in each sample. Phylogenetic analysis of this sequence showed that the bacterium from which it was derived, tentatively designated IricES1, is part of a novel clade in the alpha subdivision of the Proteobacteria. ISH and PCR assays of various tissues performed with oligonucleotides specific for the IricES1 16S rRNA showed that IricES1 is restricted to ovarian cells. Based on the results obtained, we inferred that the bacteria seen by EM in ovarian ceils are a single type of bacteria, corresponding to IricES1. PCR screening of 166 ticks from various parts of Italy and one site in England showed that IricES1 was present in 96% of adult females and 44% of nymphs (unsexed). No adult males were found to be infected. Despite the apparent parasitism of host mitochondria by IricES1, the available information suggests that the bacterium has an obligate relationship with its host, although this must be confirmed. [ABSTRACT FROM AUTHOR]

Summary: Bacteria of the genus Asaia are associated with different species of malaria vectors and are located in the midgut, salivary glands and reproductive organs of female and male mosquitoes. Based on current evidence, the spreading of these bacteria in mosquito populations occurs through different mechanisms: co-feeding, sexual mating, and maternal transmission . Even though paternal transmission of insect symbionts to progeny is not commonplace, the presence of Asaia in the male reproductive organs makes this additional transmission route worth being investigated. Here, we show that male-borne Asaia are transferred to females during the mating of Anopheles stephensi mosquitoes. Subsequently, the bacteria acquired by the female are vertically transmitted to the progeny. It would thus be possible to use male mosquitoes, which do not bite, to spread Asaia strains interfering with malaria transmission. [Copyright &y& Elsevier]