Mycobacteriophages are viruses that infect mycobacterial hosts such as Mycobacterium smegmatis and Mycobacterium tuberculosis. All mycobacteriophages characterized to date are dsDNA tailed phages, and have either siphoviral or myoviral morphotypes. However, their genetic diversity is considerable, and although sixty-two genomes have been sequenced and comparatively analyzed, these likely represent only a small portion of the diversity of the mycobacteriophage population at large. Here we report the isolation, sequencing and comparative genomic analysis of 18 new mycobacteriophages isolated from geographically distinct locations within the United States. Although no clear correlation between location and genome type can be discerned, these genomes expand our knowledge of mycobacteriophage diversity and enhance our understanding of the roles of mobile elements in viral evolution. Expansion of the number of mycobacteriophages grouped within Cluster A provides insights into the basis of immune specificity in these temperate phages, and we also describe a novel example of apparent immunity theft. The isolation and genomic analysis of bacteriophages by freshman college students provides an example of an authentic research experience for novice scientists.

Cao et al. report a new mechanism by which Zika virus maternal-fetal transmission may occur and be limited as autophagy inhibition protects mice from vertical viral transmission. This study suggests that an autophagy-based therapeutic intervention against ZIKV may be warranted.

The placenta is the principal organ nurturing the fetus during pregnancy and was traditionally considered to be sterile. Recent work has suggested that the placenta harbours microbial communities, however the location and possible function of these microbes remain to be confirmed and elucidated. Here, we employed genomic DNA sequencing of multiple variable (V) regions of the bacterial 16S ribosomal gene, to interrogate microbial profiles in term pregnancies, from the basal plate, which is in direct contact with maternal uterine, endothelial, and immune cells; placental villi, which are bathed in maternal blood, and fetal membranes, which encapsulate the amniotic cavity. QIIME, R package “Phyloseq” analysis was used to assess alpha and beta diversity and absolute abundance of the 16S rRNA gene per location. We demonstrate that (1) microbiota exhibit spatially distinct profiles depending on the location within the placenta and (2) “semi-composite” 16S profiles using multiple V regions validated by quantitative PCR analysis confirmed that distinct bacterial taxa dominate in different placental niches. Finally, profiles are not altered by mode of delivery. Together these findings suggest that there is niche-specificity to the placental microbiota and placental microbiome studies should consider regional differences, which may affect maternal, fetal, and/or neonatal health and physiology.

Summary Tyro3, Axl and Mertk (TAM) receptors are candidate entry receptor for infection of Zika virus (ZIKV), an emerging flavivirus of global public health concern. To investigate the requirement of TAM receptors for ZIKV infection, we employed several routes of viral inoculation and compared viral replication in wild-type vs. Axl−/−, Mertk−/−, Axl−/−Mertk−/−, and Axl−/−Tyro3−/− mice in various organs. Pregnant and non-pregnant mice treated with interferon α receptor (IFNAR)-blocking (MAR1-5A3) antibody infected subcutaneously with ZIKV showed no reliance on TAMs for infection. In the absence of IFNAR blocking antibody, adult female mice challenged intravaginally with ZIKV showed no difference in mucosal viral titers. Similarly, in young mice that were infected with ZIKV intracranially or intraperitoneally, ZIKV replication occurred in the absence of TAM receptors, and no differences in cell tropism was observed. These findings indicate that in mice, TAM receptors are not required for ZIKV entry and infection.

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Worldwide, 10% of babies are born preterm, defined as birth before 37 weeks’ gestation. We have had little success in developing strategies to prevent preterm births, the majority of which are due to infection or are idiopathic. An emerging hypothesis is that the maternal microbiome – the bacteria that inhabit the mother’s body and play vital functions in normal health – contributes to the etiology of preterm birth. Here, we highlight the latest data revealing correlations between preterm birth and maternal intestinal, vaginal, cervical, and placental microbiomes. Additionally, we describe the most commonly used comparative microbiome analysis methods and highlight important issues to consider when conducting such studies.

Autophagy is a ubiquitous cell recycling pathway that delivers cytoplasmic constituents to the lysosome and is essential for normal cellular function. Autophagic activity is up‐regulated under physiological conditions as well as stressful conditions such as nutrient deprivation, oxidative stress, hypoxia, inflammation, and infection. Thus, it is essential to regard the functional importance of the pathway and its components in a given tissue context. Here we review what is known about the involvement of autophagy process during physiological processes in the female reproductive tract and in pregnancy from preimplantation to oocyte function to placental development, parturition, and postpartum remodeling of the uterus; as well as in pathological and adverse events during these processes.

Controversy about whether there are microbes in the placenta and if they have any functional importance during pregnancy and for neonatal health is ongoing. Previous work has demonstrated that the basal plate (BP), comprising maternal and fetal derived cells harbors intracellular bacteria. 16S sequencing and bacterial species-specific analysis of term placentas revealed that the gram-negative bacillus Ralstonia insidiosa, native to aqueous environments and an effective biofilm promoter, comprises the most abundant species in the BP. Here, we demonstrate whether R. insidiosa cells home to a particular niche in the BP, how they may arrive there, and whether they are associated with adverse outcomes. We developed methods to detect and study cell-specific localization of R.insidiosa using ex vivo and in vitro models. Additionally, we studied potential routes of R.insidiosa entry into the placenta. We show that R. insidiosa is a bona fide resident in human placental BP. It can access trophoblast cells in culture and within basal plate tissues where it localizes to intracellular single-membrane vacuoles and can replicate.However, the presence of R. insidiosa does not cause cell death and does not induce a pro-inflammatory immune response suggesting that it is not harmful in and of itself.Finally, we show that in a pregnant mouse model, R. insidiosa traffics to the placenta via the intrauterine route but does not induce preterm labor or preterm birth. Together, our findings provide a foundation for understanding non-pathogenic placental cell-microbe interactions and the functional importance of R. insidiosa in placental health and physiology.