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ObjectiveThe goals of this study were to characterize bacterial communities within fecal samples, pancreatic fluid, bile, and jejunal contents from patients undergoing pancreaticoduodenectomy (PD) and to identify associations between microbiome profiles and clinical variables.MethodsFluid was collected from the pancreas, common bile duct, and proximal jejunum from 50 PD patients. Postoperative fecal samples were also collected. The microbial burden within samples was quantified with droplet digital polymerase chain reaction. Bacterial 16S ribosomal RNA gene sequences were amplified, sequenced, and analyzed. Data from fecal samples were compared with publicly available data obtained from volunteers.ResultsDroplet digital polymerase chain reaction confirmed the presence of bacteria in all sample types, including pancreatic fluid. Relative to samples from the American Gut Project, fecal samples from PD patients were enriched with Klebsiella and Bacteroides and were depleted of anaerobic taxa (eg, Roseburia and Faecalibacterium). Similar patterns were observed within PD pancreas, bile, and jejunal samples. Postoperative fecal samples from patients with a pancreatic fistula contained increased abundance of Klebsiella and decreased abundance of commensal anaerobes, for example, Ruminococcus.ConclusionsThis study confirms the presence of altered bacterial populations within samples from PD patients. Future research must validate these findings and may evaluate targeted microbiome modifications to improve outcomes in PD patients.

Since the first description of adenoviruses in bats in 2006, a number of micro- and megabat species in Europe, Africa, and Asia have been shown to carry a wide diversity of adenoviruses. Here, we report on the evolutionary, biological, and structural characterization of a novel bat adenovirus (BtAdV) recovered from a Rafinesque's big-eared bat (Corynorhinus rafinesquii) in Kentucky, USA, which is the first adenovirus isolated from North American bats. This virus (BtAdV 250-A) exhibits a close phylogenetic relationship with Canine mastadenovirus A (CAdV A), as previously observed with other BtAdVs. To further investigate the relationships between BtAdVs and CAdVs, we conducted mass spectrometric analysis and single-particle cryo-electron microscopy reconstructions of the BtAdV 250-A capsid and also analyzed the in vitro host ranges of both viruses. Our results demonstrate that BtAdV 250-A represents a new mastadenovirus species that, in contrast to CAdV, has a unique capsid morphology that contains more prominent extensions of protein IX and can replicate efficiently in a phylogenetically diverse range of species. These findings, in addition to the recognition that both the genetic diversity of BtAdVs and the number of different bat species from disparate geographic regions infected with BtAdVs appears to be extensive, tentatively suggest that bats may have served as a potential reservoir for the cross-species transfer of adenoviruses to other hosts, as theorized for CAdV. Although many adenoviruses are host specific and likely codiverged with their hosts over millions of years, other adenoviruses appear to have emerged through successful cross-species transmission events on more recent time scales. The wide geographic distribution and genetic diversity of adenoviruses in bats and their close phylogenetic relationship to Canine mastadenovirus A (CAdV A) has raised important questions about how CAdV A, and possibly other mammalian adenoviruses, may have emerged. Although most adenoviruses tend to cause limited disease in their natural hosts, CAdV A is unusual in that it may cause high morbidity and sometimes fatal infections in immunocompetent hosts and is thus an important pathogen of carnivores. Here, we performed a comparative evolutionary and structural study of representative bat and canine adenoviruses to better understand the relationship between these two viral groups.

RationaleMicrobiome studies typically focus on bacteria, but fungal species are common in many body sites and can have profound effects on the host. Wide gaps exist in the understanding of the fungal microbiome (mycobiome) and its relationship to lung disease.ObjectivesTo characterize the mycobiome at different respiratory tract levels in persons with and without HIV infection and in HIV-infected individuals with chronic obstructive pulmonary disease (COPD).MethodsOral washes (OW), induced sputa (IS), and bronchoalveolar lavages (BAL) were collected from 56 participants. We performed 18S and internal transcribed spacer sequencing and used the neutral model to identify fungal species that are likely residents of the lung. We used ubiquity-ubiquity plots, random forest, logistic regression, and metastats to compare fungal communities by HIV status and presence of COPD.Measurements and main resultsMycobiomes of OW, IS, and BAL shared common organisms, but each also had distinct members. Candida was dominant in OW and IS, but BAL had 39 fungal species that were disproportionately more abundant than in the OW. Fungal communities in BAL differed significantly by HIV status and by COPD, with Pneumocystis jirovecii significantly overrepresented in both groups. Other fungal species were also identified as differing in HIV and COPD.ConclusionsThis study systematically examined the respiratory tract mycobiome in a relatively large group. By identifying Pneumocystis and other fungal species as overrepresented in the lung in HIV and in COPD, it is the first to determine alterations in fungal communities associated with lung dysfunction and/or HIV, highlighting the clinical relevance of these findings. Clinical trial registered with www.clinicaltrials.gov (NCT00870857).

UnlabelledSince 1998, cyclic mortality events in common eiders (Somateria mollissima), numbering in the hundreds to thousands of dead birds, have been documented along the coast of Cape Cod, MA, USA. Although longitudinal disease investigations have uncovered potential contributing factors responsible for these outbreaks, detecting a primary etiological agent has proven enigmatic. Here, we identify a novel orthomyxovirus, tentatively named Wellfleet Bay virus (WFBV), as a potential causative agent of these outbreaks. Genomic analysis of WFBV revealed that it is most closely related to members of the Quaranjavirus genus within the family Orthomyxoviridae. Similar to other members of the genus, WFBV contains an alphabaculovirus gp64-like glycoprotein that was demonstrated to have fusion activity; this also tentatively suggests that ticks (and/or insects) may vector the virus in nature. However, in addition to the six RNA segments encoding the prototypical structural proteins identified in other quaranjaviruses, a previously unknown RNA segment (segment 7) encoding a novel protein designated VP7 was discovered in WFBV. Although WFBV shows low to moderate levels of sequence similarity to Quaranfil virus and Johnston Atoll virus, the original members of the Quaranjavirus genus, additional antigenic and genetic analyses demonstrated that it is closely related to the recently identified Cygnet River virus (CyRV) from South Australia, suggesting that WFBV and CyRV may be geographic variants of the same virus. Although the identification of WFBV in part may resolve the enigma of these mass mortality events, the details of the ecology and epidemiology of the virus remain to be determined.ImportanceThe emergence or reemergence of viral pathogens resulting in large-scale outbreaks of disease in humans and/or animals is one of the most important challenges facing biomedicine. For example, understanding how orthomyxoviruses such as novel influenza A virus reassortants and/or mutants emerge to cause epidemic or pandemic disease is at the forefront of current global health concerns. Here, we describe the emergence of a novel orthomyxovirus, Wellfleet Bay virus (WFBV), which has been associated with cyclic large-scale bird die-offs in the northeastern United States. This initial characterization study provides a foundation for further research into the evolution, epidemiology, and ecology of newly emerging orthomyxoviruses, such as WFBV, and their potential impacts on animal and/or human health.

The human microbiome contributes to health and disease, but the oral microbiota is understudied relative to the gut microbiota. The salivary microbiota is easily accessible, underexplored, and may provide insight into response to infections. We sought to determine the composition, association with clinical features, and heterogeneity of the salivary microbiota in patients with acute lower respiratory tract infection (LRTI). We conducted a multicenter prospective cohort study of 147 adults with acute LRTI presenting to the emergency department of seven hospitals in three states (Pennsylvania, Michigan, and Ohio) between May 2017 and November 2018. Salivary samples were collected in the emergency department, at days 2–5 if hospitalized, and at day 30, as well as fecal samples if patients were willing. We compared salivary microbiota profiles from patients to those of healthy adult volunteers by sequencing and analyzing bacterial 16-rRNA. Compared to healthy volunteers, the salivary microbiota of patients with LRTI was highly distinct and strongly enriched with intestinal anaerobes such as Bacteroidaceae, Ruminococcaceae, and Lachnospiraceae (e.g., mean 10% relative abundance of Bacteroides vs < 1% in healthy volunteers). Within the LRTI population, COPD exacerbation was associated with altered salivary microbiota composition compared to other LRTI conditions. The largest determinant of microbiota variation within the LRTI population was geography (city in which the hospital was located). [ABSTRACT FROM AUTHOR]

Neonates are protected from colonizing bacteria by antibodies secreted into maternal milk. Necrotizing enterocolitis (NEC) is a disease of neonatal preterm infants with high morbidity and mortality that is associated with intestinal inflammation driven by the microbiota.sup.1-3. The incidence of NEC is substantially lower in infants fed with maternal milk, although the mechanisms that underlie this benefit are not clear.sup.4-6. Here we show that maternal immunoglobulin A (IgA) is an important factor for protection against NEC. Analysis of IgA binding to fecal bacteria from preterm infants indicated that maternal milk was the predominant source of IgA in the first month of life and that a relative decrease in IgA-bound bacteria is associated with the development of NEC. Sequencing of IgA-bound and unbound bacteria revealed that before the onset of disease, NEC was associated with increasing domination by Enterobacteriaceae in the IgA-unbound fraction of the microbiota. Furthermore, we confirmed that IgA is critical for preventing NEC in a mouse model, in which pups that are reared by IgA-deficient mothers are susceptible to disease despite exposure to maternal milk. Our findings show that maternal IgA shapes the host-microbiota relationship of preterm neonates and that IgA in maternal milk is a critical and necessary factor for the prevention of NEC. Immunoglobulin A antibodies in maternal milk are required for prevention of necrotizing enterocolitis in preterm neonates., Author(s): Kathyayini P. Gopalakrishna [sup.1] [sup.2] , Benjamin R. Macadangdang [sup.1] [sup.3] , Matthew B. Rogers [sup.4] , Justin T. Tometich [sup.1] , Brian A. Firek [sup.4] , Robyn Baker [...]

Introduction: We have previously demonstrated that a pathologic downregulation of peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC1α) within the intestinal epithelium contributes to the pathogenesis of inflammatory bowel disease (IBD). However, the mechanism underlying downregulation of PGC1α expression and activity during IBD is not yet clear. Methods: Mice (male; C57Bl/6, Villincre/+;Pgc1afl/fl mice, and Pgc1afl/fl) were subjected to experimental colitis and treated with nicotinamide riboside. Western blot, high-resolution respirometry, nicotinamide adenine dinucleotide (NAD+) quantification, and immunoprecipitation were used to in this study. Results: We demonstrate a significant depletion in the NAD+ levels within the intestinal epithelium of mice undergoing experimental colitis, as well as humans with ulcerative colitis. While we found no decrease in the levels of NAD + -synthesizing enzymes within the intestinal epithelium of mice undergoing experimental colitis, we did find an increase in the mRNA level, as well as the enzymatic activity, of the NAD + -consuming enzyme poly(ADP-ribose) polymerase-1 (PARP1). Treatment of mice undergoing experimental colitis with an NAD+ precursor reduced the severity of colitis, restored mitochondrial function, and increased active PGC1α levels; however, NAD+ repletion did not benefit transgenic mice that lack PGC1α within the intestinal epithelium, suggesting that the therapeutic effects require an intact PGC1α axis. Discussion: Our results emphasize the importance of PGC1α expression to both mitochondrial health and homeostasis within the intestinal epithelium and suggest a novel therapeutic approach for disease management. These findings also provide a mechanistic basis for clinical trials of nicotinamide riboside in IBD patients. [ABSTRACT FROM AUTHOR]

Background Although the healthy human skin microbiome has been the subject of recent studies, it is not known whether alterations among commensal microbes contribute to surgical site infections (SSIs). Our objective in this study was to characterize temporal and spatial variation in the skin microbiota of patients undergoing colorectal surgery and determine if dysbiosis contributes to SSIs. Methods Sixty one adults scheduled to undergo elective colon or rectal resection were identified by convenience sampling. By analyzing bacterial 16S rRNA gene sequences isolated from clinical samples, we used a culture-independent strategy to monitor perioperative changes in microbial diversity of fecal samples and the skin. Results A total of 990 samples from 61 patients were analyzed. Alpha diversity on the skin decreased after surgery but later recovered at the postoperative clinic visit. In most patients, we observed a transient postoperative loss of skin commensals (Corynebacterium and Propionibacterium) at the surgical site, which were replaced by potential pathogens and intestinal anaerobes (eg, Enterobacteriaceae). These changes were not observed on skin that was uninvolved in the surgical incision (chest wall). One patient developed a wound infection. Incisional skin swabs from this patient demonstrated a sharp postoperative increase in the abundance of Enterococcus , which was also cultured from wound drainage. Conclusions We observed reproducible perioperative changes in the skin microbiome following surgery. The low incidence of SSIs in this cohort precluded analysis of associations between dysbiosis and infection. We postulate that real-time monitoring of the skin microbiome could provide actionable findings about the pathogenesis of SSIs. [ABSTRACT FROM AUTHOR]

Abstract Background Lateral gene transfer is increasingly invoked to explain phylogenetic results that conflict with our understanding of organismal relationships. In eukaryotes, the most common observation interpreted in this way is the appearance of a bacterial gene (one that is not clearly derived from the mitochondrion or plastid) in a eukaryotic nuclear genome. Ideally such an observation would involve a single eukaryote or a small group of related eukaryotes encoding a gene from a specific bacterial lineage. Results Here we show that several apparently simple cases of lateral transfer are actually more complex than they originally appeared: in these instances we find that two or more distantly related eukaryotic groups share the same bacterial gene, resulting in a punctate distribution. Specifically, we describe phylogenies of three core carbon metabolic enzymes: transketolase, glyceraldehyde-3-phosphate dehydrogenase and ribulose-5-phosphate-3-epimerase. Phylogenetic trees of each of these enzymes includes a strongly-supported clade consisting of several eukaryotes that are distantly related at the organismal level, but whose enzymes are apparently all derived from the same lateral transfer. With less sampling any one of these examples would appear to be a simple case of bacterium-to-eukaryote lateral transfer; taken together, their evolutionary histories cannot be so simple. The distributions of these genes may represent ancient paralogy events or genes that have been transferred from bacteria to an ancient ancestor of the eukaryotes that retain them. They may alternatively have been transferred laterally from a bacterium to a single eukaryotic lineage and subsequently transferred between distantly related eukaryotes. Conclusion Determining how complex the distribution of a transferred gene is depends on the sampling available. These results show that seemingly simple cases may be revealed to be more complex with greater sampling, suggesting many bacterial genes found in eukaryotic genomes may have a punctate distribution.

Abstract Background Horizontal or lateral transfer of genetic material between distantly related prokaryotes has been shown to play a major role in the evolution of bacterial and archaeal genomes, but exchange of genes between prokaryotes and eukaryotes is not as well understood. In particular, gene flow from eukaryotes to prokaryotes is rarely documented with strong support, which is unusual since prokaryotic genomes appear to readily accept foreign genes. Results Here, we show that abundant marine cyanobacteria in the related genera Synechococcus and Prochlorococcus acquired a key Calvin cycle/glycolytic enzyme from a eukaryote. Two non-homologous forms of fructose bisphosphate aldolase (FBA) are characteristic of eukaryotes and prokaryotes respectively. However, a eukaryotic gene has been inserted immediately upstream of the ancestral prokaryotic gene in several strains (ecotypes) of Synechococcus and Prochlorococcus. In one lineage this new gene has replaced the ancestral gene altogether. The eukaryotic gene is most closely related to the plastid-targeted FBA from red algae. This eukaryotic-type FBA once replaced the plastid/cyanobacterial type in photosynthetic eukaryotes, hinting at a possible functional advantage in Calvin cycle reactions. The strains that now possess this eukaryotic FBA are scattered across the tree of Synechococcus and Prochlorococcus, perhaps because the gene has been transferred multiple times among cyanobacteria, or more likely because it has been selectively retained only in certain lineages. Conclusion A gene for plastid-targeted FBA has been transferred from red algae to cyanobacteria, where it has inserted itself beside its non-homologous, functional analogue. Its current distribution in Prochlorococcus and Synechococcus is punctate, suggesting a complex history since its introduction to this group.

Abstract Background EFL (or elongation factor-like) is a member of the translation superfamily of GTPase proteins. It is restricted to eukaryotes, where it is found in a punctate distribution that is almost mutually exclusive with elongation factor-1 alpha (EF-1α). EF-1α is a core translation factor previously thought to be essential in eukaryotes, so its relationship to EFL has prompted the suggestion that EFL has spread by horizontal or lateral gene transfer (HGT or LGT) and replaced EF-1α multiple times. Among green algae, trebouxiophyceans and chlorophyceans have EFL, but the ulvophycean Acetabularia and the sister group to green algae, land plants, have EF-1α. This distribution singles out green algae as a particularly promising group to understand the origin of EFL and the effects of its presence on EF-1α. Results We have sampled all major lineages of green algae for both EFL and EF-1α. EFL is unexpectedly broad in its distribution, being found in all green algal lineages (chlorophyceans, trebouxiophyceans, ulvophyceans, prasinophyceans, and mesostigmatophyceans), except charophyceans and the genus Acetabularia. The presence of EFL in the genus Mesostigma and EF-1α in Acetabularia are of particular interest, since the opposite is true of all their closest relatives. The phylogeny of EFL is poorly resolved, but the Acetabularia EF-1α is clearly related to homologues from land plants and charophyceans, demonstrating that EF-1α was present in the common ancestor of the green lineage. Conclusion The distribution of EFL and EF-1α in the green lineage is not consistent with the phylogeny of the organisms, indicating a complex history of both genes. Overall, we suggest that after the introduction of EFL (in the ancestor of green algae or earlier), both genes co-existed in green algal genomes for some time before one or the other was lost on multiple occasions.

Abstract Background The nucleomorphs associated with secondary plastids of cryptomonads and chlorarachniophytes are the sole examples of organelles with eukaryotic nuclear genomes. Although not as widespread as their prokaryotic equivalents in mitochondria and plastids, nucleomorph genomes share similarities in terms of reduction and compaction. They also differ in several aspects, not least in that they encode proteins that target to the plastid, and so function in a different compartment from that in which they are encoded. Results Here, we test whether the phylogenetically distinct nucleomorph genomes of the cryptomonad, Guillardia theta, and the chlorarachniophyte, Bigelowiella natans, have experienced similar evolutionary pressures during their transformation to reduced organelles. We compared the evolutionary rates of genes from nuclear, nucleomorph, and plastid genomes, all of which encode proteins that function in the same cellular compartment, the plastid, and are thus subject to similar selection pressures. Furthermore, we investigated the divergence of nucleomorphs within cryptomonads by comparing G. theta and Rhodomonas salina. Conclusion Chlorarachniophyte nucleomorph genes have accumulated errors at a faster rate than other genomes within the same cell, regardless of the compartment where the gene product functions. In contrast, most nucleomorph genes in cryptomonads have evolved faster than genes in other genomes on average, but genes for plastid-targeted proteins are not overly divergent, and it appears that cryptomonad nucleomorphs are not presently evolving rapidly and have therefore stabilized. Overall, these analyses suggest that the forces at work in the two lineages are different, despite the similarities between the structures of their genomes.