Novel evolutionary insights on the interactions of the Holosporales (Alphaproteobacteria) with eukaryotic hosts from comparative genomics.

Holosporales are an alphaproteobacterial order engaging in obligate and complex associations with eukaryotes, in particular protists. The functional and evolutionary features of those interactions are still largely undisclosed. Here, we sequenced the genomes of two members of the species Bealeia paramacronuclearis (Holosporales, Holosporaceae) intracellularly associated with the ciliate protist Paramecium, which resulted in high correspondence. Consistent with the short-branched early-divergent phylogenetic position, Bealeia presents a larger functional repertoire than other Holosporaceae, comparable to those of other Holosporales families, particularly for energy metabolism and motility. Our analyses indicate that different Holosporales likely experienced at least partly autonomous genome reduction and adaptation to host interactions, for example regarding dependence on host biotin driven by multiple independent horizontal acquisitions of transporters. Among Alphaproteobacteria, this is reminiscent of the convergently evolved Rickettsiales, which however appear more diverse, possibly due to a probably more ancient origin. We identified in Bealeia and other Holosporales the plasmid-encoded putative genetic determinants of R-bodies, which may be involved in a killer trait towards symbiont-free hosts. While it is not clear whether these genes are ancestral or recently horizontally acquired, an intriguing and peculiar role of R-bodies is suggested in the evolution of the interactions of multiple Holosporales with their hosts.

'Candidatus Gromoviella agglomerans', a novel intracellular Holosporaceae parasite of the ciliate Paramecium showing marked genome reduction.

Holosporales are an alphaproteobacterial lineage encompassing bacteria obligatorily associated with multiple diverse eukaryotes. For most representatives, little is known on the interactions with their hosts. In this study, we characterized a novel Holosporales symbiont of the ciliate Paramecium polycaryum. This bacterium inhabits the host cytoplasm, frequently forming quite large aggregates. Possibly due to such aggregates, host cells sometimes displayed lethal division defects. The symbiont was also able to experimentally stably infect another Paramecium polycaryum strain. The bacterium is phylogenetically related with symbionts of other ciliates and diplonemids, forming a putatively fast-evolving clade within the family Holosporaceae. Similarly to many close relatives, it presents a very small genome (<600 kbp), and, accordingly, a limited predicted metabolism, implying a heavy dependence on Paramecium, thanks also to some specialized membrane transporters. Characterized features, including the presence of specific secretion systems, are overall suggestive of a mild parasitic effect on the host. From an evolutionary perspective, a potential ancestral trend towards pronounced genome reduction and possibly linked to parasitism could be inferred, at least among fast-evolving Holosporaceae, with some lineage-specific traits. Interestingly, similar convergent features could be observed in other host-associated lineages, in particular Rickettsiales among Alphaproteobacteria.

Diauxie and co-utilization of carbon sources can coexist during bacterial growth in nutritionally complex environments.

It is commonly thought that when multiple carbon sources are available, bacteria metabolize them either sequentially (diauxic growth) or simultaneously (co-utilization). However, this view is mainly based on analyses in relatively simple laboratory settings. Here we show that a heterotrophic marine bacterium, Pseudoalteromonas haloplanktis, can use both strategies simultaneously when multiple possible nutrients are provided in the same growth experiment. The order of nutrient uptake is partially determined by the biomass yield that can be achieved when the same compounds are provided as single carbon sources. Using transcriptomics and time-resolved intracellular 1H-13C NMR, we reveal specific pathways for utilization of various amino acids. Finally, theoretical modelling indicates that this metabolic phenotype, combining diauxie and co-utilization of substrates, is compatible with a tight regulation that allows the modulation of assimilatory pathways.

Natural biocide disrupts nestmate recognition in honeybees.

Honeybee colonies are under the threat of many stressors, biotic and abiotic factors that strongly affect their survival. Recently, great attention has been directed at chemical pesticides, including their effects at sub-lethal doses on bee behaviour and colony success; whereas the potential side effects of natural biocides largely used in agriculture, such as entomopathogenic fungi, have received only marginal attention. Here, we report the impact of the fungus Beauveria bassiana on honeybee nestmate recognition ability, a crucial feature at the basis of colony integrity. We performed both behavioural assays by recording bee guards' response towards foragers (nestmate or non-nestmate) either exposed to B. bassiana or unexposed presented at the hive entrance, and GC-MS analyses of the cuticular hydrocarbons (CHCs) of fungus-exposed versus unexposed bees. Our results demonstrated that exposed bees have altered cuticular hydrocarbons and are more easily accepted into foreign colonies than controls. Since CHCs are the main recognition cues in social insects, changes in their composition appear to affect nestmate recognition ability at the colony level. The acceptance of chemically unrecognizable fungus-exposed foragers could therefore favour forager drift and disease spread across colonies.

Management of bronchial secretions with Free Aspire in children with cerebral palsy: impact on clinical outcomes and healthcare resources.

BACKGROUND: Management of secretions in children with cerebral palsy is often problematic due to severe deformation of the rib cage, impaired cough, and patients'inability to collaborate with chest physiotherapy. Assessing the effectiveness of different methods and techniques of secretion clearance is hampered by the lack of direct outcome measures and by limited patient cooperation. This observational study was planned to evaluate the efficacy of Free Aspire, a device that utilizes a special method to remove secretions from the bronchial tree in hypersecretive patients. CASE PRESENTATION: Cerebral palsy patients were selected who had experienced more than 3 episodes of respiratory exacerbations in the latest year despite therapeutic optimization (including bronchial clearance techniques) and who had received at least one antibiotic course or underwent at least one access to the Emergency Room (ER) or admission to hospital in the 6 months prior to the study. Patients with congestive heart failure or contraindications for Free Aspire were excluded. We prospectively enrolled 8 patients (mean age 8.25 ± 6.11 years) who had been using in the past techniques for clearance secretions different from Free Aspire. The treatment with Free Aspire consisted of at least two 20-min sessions per day. The observational study period was 18 months. In the 6 months prior to start the treatment (T0), patients had a mean number of 4.0 ± 2.23 visits from the primary care pediatrician (PCP), spent 14 ± 20 days in hospital, and received antibiotics for 35 ± 17 days. After the first 6 months of treatment (T1), they had 1.7 ± 0.73 PCP visits, no days spent in hospital, and 9.75 ± 10.4 days of antibiotic therapy. At 12 months of treatment (T2), PCP visits were 1.7 ± 0.70, days in hospital 1.12 ± 0.3, and days of antibiotics 10.25 ± 10. At 18 months of treatment (T3) no hospitalizations had occurred, PCP visits were 0.25 ± 0.70, and days of antibiotic therapy 4.8 ± 12.62. The technique proved to be safe and well tolerated. CONCLUSION: Our findings show that Free Aspire for bronchial secretion clearance in cerebral palsy patients with limited capacity to collaborate is safe and effective in reducing the impact of respiratory exacerbations in terms of number of PCP visits, days spent in hospital, and days of antibiotic therapy; its regular use maintains this effect in time.

Noninvasive and invasive ventilation and enteral nutrition for ALS in Italy.

INTRODUCTION: We performed a population-based study to assess amyotrophic lateral sclerosis (ALS) survival after noninvasive ventilation (NIV), invasive ventilation (IV), and enteral nutrition (EN). METHODS: We included patients diagnosed from 2000 to 2009 in Modena, where a prospective registry and a Motor Neuron Diseases Centre have been active since 2000. RESULTS: Of the 193 incident cases, 47.7% received NIV, 24.3% received tracheostomy, and 49.2% received EN. A total of 10.4% of the patients refused NIV, 31.6% refused IV, and 8.7% refused EN. The median survival times after NIV, IV, and EN were 15, 19, and 9 months, respectively. Of the tracheostomized patients, 79.7% were discharged from the hospital; 73.0% were discharged to home. The median survival times for tracheostomized patients who were cared for at home and in nursing homes were 43 and 2 months, respectively. The multivariate analysis demonstrated that the place of discharge was the only independent prognostic factor after IV (P<0.01). CONCLUSIONS: Service organizations may promote adherence to NIV, IV, EN, and influence postprocedure survival. These data may be useful in defining health plans regarding advanced ALS care and in patient counseling.

A clear case of chronic aspiration of starch (potato).

One of the known agent that causes an organizing pneumonia could be the chronic inhalation of food, but generally we can't find the specific food that caused this pattern. We show a case where, with an accurate medical history, supported by the various histological investigation steps, we could reach the specific cause of it.

Unexpected positron emission tomography-positive actinomyces-related mass of the bronchial stump.

Pulmonary actinomycosis is a rare disease frequently misdiagnosed, even by experienced clinicians, as primary or metastatic lung cancer or as other more conventional lung infections. It is often an unexpected disease that is basically detected only on cytological/histological examination. A case involving a patient who presented with a mass in the bronchial stump (of a previous pulmonary lobectomy) is described. Despite a strong suspicion of recurrent lung cancer, positron emission tomography confirmed a diagnosis of a suture-related bronchial actinomycosis.

Biomass and mineral element responses of a Serengeti short-grass species to nitrogen supply and defoliation: compensation requires a critical [N].

Large mammalian herbivores in grassland ecosystems influence plant growth dynamics in many ways, including the removal of plant biomass and the return of nutrients to the soil. A 10-week growth chamber experiment examined the responses of Sporobolus kentrophyllus from the heavily grazed short-grass plains of Serengeti National Park, Tanzania, to simulated grazing and varying nitrogen nutrition. Plants were subjected to two clipping treatments (clipped and unclipped) and five nitrogen levels (weekly applications at levels equivalent to 0, 1, 5, 10, and 40 g N m-2), the highest being equivalent to a urine hit. Tiller and stolon production were measured weekly. Total biomass at harvest was partitioned by plant organ and analyzed for nitrogen and mineral element composition. Tiller and stolon production reached a peak at 3-5 weeks in unclipped plants, then declined drastically, but tiller number increased continually in clipped plants; this differential effect was enhanced at higher N levels. Total plant production increased substantially with N supply, was dominated by aboveground production, and was similar in clipped and unclipped plants, except at high nitrogen levels where clipped plants produced more. Much of the standing biomass of unclipped plants was standing dead and stem; most of the standing biomass of clipped plants was live leaf with clipped plants having significantly more leaf than unclipped plants. However, leaf nitrogen was stimulated by clipping only in plants receiving levels of N application above 1 g N m-2 which corresponded to a tissue concentration of 2.5% N. Leaf N concentration was lower in unclipped plants and increased with level of N. Aboveground N and mineral concentrations were consistently greater than belowground levels and while clipping commonly promoted aboveground concentrations, it generally diminished those belowground. In general, clipped plants exhibited increased leaf elemental concentrations of K, P, and Mg. Concentrations of B, Ca, K, Mg, and Zn increased with the level of N. No evidence was found that the much greater growth associated with higher N levels diminished the concentration of any other nutrient and that clipping coupled with N fertilization increased the total mineral content available in leaf tissue. The results suggest that plants can (1) compensate for leaf removal, but only when N is above a critical point (tissue [N] 2.8%) and (2) grazing coupled with N fertilization can increase the quality and quantity of tissue available for herbivore removal.