Proteobacteria impair anti-tumor immunity in the omentum by consuming arginine.

Gut microbiota influence anti-tumor immunity, often by producing immune-modulating metabolites. However, microbes consume a variety of metabolites that may also impact host immune responses. We show that tumors grow unchecked in the omenta of microbe-replete mice due to immunosuppressive Tregs.

Factors Affecting the Gut Microbiome in Pediatric Intestinal Failure.

Background: There is little data on gut microbiome and various factors that lead to dysbiosis in pediatric intestinal failure (PIF). This study aimed to characterize gut microbiome in PIF and determine factors that may affect microbial composition in these patients.

Methods: This is a single-center, prospective cohort study of children with PIF followed at our intestinal rehabilitation program.

Scheduled Empiric Antibiotics May Alter the Gut Microbiome and Nutrition Outcomes in Pediatric Intestinal Failure.

Background: In this study, we aim to determine the effect of scheduled antibiotics on gut microbiome in pediatric intestinal failure (IF) and to evaluate the effect of the gut microbiome on nutrition outcomes in IF.

Methods: Fecal samples were collected at regular intervals from pediatric patients with IF for gut microbiome comparison between 2 cohorts: (group 1) those on scheduled prophylactic antibiotics and (group 2) those who were not on scheduled antibiotics. Gut microbiome composition and diversity were compared among the 2 cohorts.

Obesogenic diet in aging mice disrupts gut microbe composition and alters neutrophil:lymphocyte ratio, leading to inflamed milieu in acute heart failure.

Calorie-dense obesogenic diet (OBD) is a prime risk factor for cardiovascular disease in aging. However, increasing age coupled with changes in the diet can affect the interaction of intestinal microbiota influencing the immune system, which can lead to chronic inflammation. How age and calorie-enriched OBD interact with microbial flora and impact leukocyte profiling is currently under investigated.

Composition and richness of the serum microbiome differ by age and link to systemic inflammation.

Advanced age has been associated with alterations to the microbiome within the intestinal tract as well as intestinal permeability (i.e., "leaky gut").

Erratum: Author Correction: Identification of donor microbe species that colonize and persist long term in the recipient after fecal transplant for recurrent .

[This corrects the article DOI: 10.1038/s41522-017-0020-7.].

Distal airway microbiome is associated with immunoregulatory myeloid cell responses in lung transplant recipients.

Background: Long-term survival of lung transplant recipients (LTRs) is limited by the occurrence of bronchiolitis obliterans syndrome (BOS). Recent evidence suggests a role for microbiome alterations in the occurrence of BOS, although the precise mechanisms are unclear. In this study we evaluated the relationship between the airway microbiome and distinct subsets of immunoregulatory myeloid-derived suppressor cells (MDSCs) in LTRs.

Comparison of two bioinformatics tools used to characterize the microbial diversity and predictive functional attributes of microbial mats from Lake Obersee, Antarctica.

In this study, using NextGen sequencing of the collective 16S rRNA genes obtained from two sets of samples collected from Lake Obersee, Antarctica, we compared and contrasted two bioinformatics tools, PICRUSt and Tax4Fun. We then developed an R script to assess the taxonomic and predictive functional profiles of the microbial communities within the samples. Taxa such as Pseudoxanthomonas, Planctomycetaceae, Cyanobacteria Subsection III, Nitrosomonadaceae, Leptothrix, and Rhodobacter were exclusively identified by Tax4Fun that uses SILVA database; whereas PICRUSt that uses Greengenes database uniquely identified Pirellulaceae, Gemmatimonadetes A1-B1, Pseudanabaena, Salinibacterium and Sinobacteraceae.

Identification of donor microbe species that colonize and persist long term in the recipient after fecal transplant for recurrent .

Fecal microbiota transplantation has been shown to be an effective treatment for patients with recurrent colitis. Although fecal microbiota transplantation helps to re-establish a normal gut function in patients, the extent of the repopulation of the recipient microbial community varies. To further understand this variation, it is important to determine the fate of donor microbes in the patients following fecal microbiota transplantation.

Metagenomics approach to the study of the gut microbiome structure and function in zebrafish Danio rerio fed with gluten formulated diet.

In this study, we report the gut microbial composition and predictive functional profiles of zebrafish, Danio rerio, fed with a control formulated diet (CFD), and a gluten formulated diet (GFD) using a metagenomics approach and bioinformatics tools. The microbial communities of the GFD-fed D. rerio displayed heightened abundances of Legionellales, Rhizobiaceae, and Rhodobacter, as compared to the CFD-fed counterparts.

The Airway Microbiome at Birth.

Alterations of pulmonary microbiome have been recognized in multiple respiratory disorders. It is critically important to ascertain if an airway microbiome exists at birth and if so, whether it is associated with subsequent lung disease. We found an established diverse and similar airway microbiome at birth in both preterm and term infants, which was more diverse and different from that of older preterm infants with established chronic lung disease (bronchopulmonary dysplasia).

Colonization potential to reconstitute a microbe community in patients detected early after fecal microbe transplant for recurrent C. difficile.

Background: Fecal microbiota transplants (FMT) are an effective treatment for patients with gut microbe dysbiosis suffering from recurrent C. difficile infections. To further understand how FMT reconstitutes the patient's gut commensal microbiota, we have analyzed the colonization potential of the donor, recipient and recipient post transplant fecal samples using transplantation in gnotobiotic mice.

Getting started with microbiome analysis: sample acquisition to bioinformatics.

Historically, in order to study microbes, it was necessary to grow them in the laboratory. It was clear though that many microbe communities were refractory to study because none of the members could be grown outside of their native habitat. The development of culture-independent methods to study microbiota using high-throughput sequencing of the 16S ribosomal RNA gene variable regions present in all prokaryotic organisms has provided new opportunities to investigate complex microbial communities.

HIV gene expression from intact proviruses positioned in bacterial artificial chromosomes at integration sites previously identified in latently infected T cells.

HIV integration predominantly occurs in introns of transcriptionally active genes. To study the impact of the integration site on HIV gene expression, a complete HIV-1 provirus (with GFP as a fusion with Nef) was inserted into bacterial artificial chromosomes (BACs) at three sites previously identified in latent T cells of patients: topoisomerase II (Top2A), DNA methyltransferase 1 (DNMT1), or basic leucine transcription factor 2 (BACH2). Transfection of BAC-HIV into 293T cells resulted in a fourfold difference in production of infectious HIV-1.

tRNA isoacceptor preference prior to retrovirus Gag-Pol junction links primer selection and viral translation.

An essential step in the replication of all retroviruses is the capture of a cellular tRNA that is used as the primer for reverse transcription. The 3'-terminal 18 nucleotides of the tRNA are complementary to the primer binding site (PBS). Moloney murine leukemia virus (MuLV) preferentially captures tRNA(Pro).

HIV-1 designed to use different tRNAGln isoacceptors prefers to select tRNAThr for replication.

Background: Previous studies have shown that infection with human immunodeficiency virus type 1 (HIV-1) causes acceleration of the synthesis of glutamine tRNA (tRNAGln) in infected cells. To investigate whether this might influence HIV-1 to utilize tRNAGln as a primer for initiation of reverse transcription, we have constructed HIV-1 proviral genomes in which the PBS and the A-loop region upstream of the PBS have been made complementary to either the anticodon region of tRNAGln,1 or tRNAGln,3 and 3' terminal 18 nucleotides of each isoacceptor of tRNAGln.

Results: Viruses in which the PBS was altered to be complementary to tRNAGln,1 or tRNAGln,3 with or without the A-loop all exhibited a lower infectivity than the wild type virus.