Slow slip source characterized by lithological and geometric heterogeneity

Slow slip events (SSEs) accommodate a significant proportion of tectonic plate motion at subduction zones, yet little is known about the faults that actually host them. The shallow depth (<2 km) of well-documented SSEs at the Hikurangi subduction zone offshore New Zealand offers a unique opportunity to link geophysical imaging of the subduction zone with direct access to incoming material that represents the megathrust fault rocks hosting slow slip. Two recent International Ocean Discovery Program Expeditions sampled this incoming material before it is entrained immediately down-dip along the shallow plate interface. Drilling results, tied to regional seismic reflection images, reveal heterogeneous lithologies with highly variable physical properties entering the SSE source region. These observations suggest that SSEs and associated slow earthquake phenomena are promoted by lithological, mechanical, and frictional heterogeneity within the fault zone, enhanced by geometric complexity associated with subduction of rough crust

Noticiero de Vigo : diario independiente de la mañana: Ano XXII Número 9648 - 1906 setembro 3

Here we demonstrate that when <i>Yersinia pesitis</i> is grown in laboratory media, peptides from the medium remain associated with cellular biomass even after washing and inactivation of the bacteria by different methods. These peptides are characteristic of the type of growth medium and of the manufacturer of the medium, reflecting the specific composition of the medium. We analyzed biomass-associated peptides from cultures of two attenuated strains of <i>Yersinia pestis</i> [KIM D27 (<i>pgm-</i>) and KIM D1 (<i>lcr-</i>)] grown in several formulations of 4 different media (tryptic soy broth (TSB), brain–heart infusion (BHI), Luria–Bertani broth (LB), and glucose (G) medium) made from components purchased from different suppliers. Despite the range of growth medium sources and the associated manufacturing processes used in their production, a high degree of peptide similarity was observed for a given medium recipe; however, notable differences in the termination points of select peptides were observed in media formulated using products from some suppliers, presumably reflecting the process by which a manufacturer performed protein hydrolysis for use in culture media. These results may help explain the presence of peptides not explicitly associated with target organisms during proteomic analysis of microbes and other biological systems that require culturing. While the primary aim of this work is to outline the range and type of medium peptides associated with <i>Yersinia pestis</i> biomass and improve the quality of proteomic measurements, these peptides may also represent a potentially useful forensic signature that could provide information about microbial culturing conditions

Phototrophic biofilm assembly in microbial-mat-derived unicyanobacterial consortia: model systems for the study of autotroph-heterotroph interactions

Microbial autotroph-heterotroph interactions influence biogeochemical cycles on a global scale, but the diversity and complexity of natural systems and their intractability to in situ manipulation make it challenging to elucidate the principles governing these interactions. The study of assembling phototrophic biofilm communities provides a robust means to identify such interactions and evaluate their contributions to the recruitment and maintenance of phylogenetic and functional diversity over time. To examine primary succession in phototrophic communities, we isolated two unicyanobacterial consortia from the microbial mat in Hot Lake, Washington, characterizing the membership and metabolic function of each consortium. We then analyzed the spatial structures and quantified the community compositions of their assembling biofilms. The consortia retained the same suite of heterotrophic species, identified as abundant members of the mat and assigned to Alphaproteobacteria , Gammaproteobacteria , and Bacteroidetes. Autotroph growth rates dominated early in assembly, yielding to increasing heterotroph growth rates late in succession. The two consortia exhibited similar assembly patterns, with increasing relative abundances of members from Bacteroidetes and Alphaproteobacteria concurrent with decreasing relative abundances of those from Gammaproteobacteria . Despite these similarities at higher taxonomic levels, the relative abundances of individual heterotrophic species were substantially different in the developing consortial biofilms. This suggests that, although similar niches are created by the cyanobacterial metabolisms, the resulting webs of autotroph-heterotroph and heterotroph-heterotroph interactions are specific to each primary producer. The relative simplicity and tractability of the Hot Lake unicyanobacterial consortia make them useful model systems for deciphering interspecies interactions and assembly principles relevant to natural microbial communities

Insights from a workplace SARS-CoV-2 specimen collection program, with genomes placed into global sequence phylogeny.

In 2020, the Department of Energy established the National Virtual Biotechnology Laboratory (NVBL) to address key challenges associated with COVID-19. As part of that effort, Pacific Northwest National Laboratory (PNNL) established a capability to collect and analyze specimens from employees who self-reported symptoms consistent with the disease. During the spring and fall of 2021, 688 specimens were screened for SARS-CoV-2, with 64 (9.3%) testing positive using reverse-transcriptase quantitative PCR (RT-qPCR). Of these, 36 samples were released for research. All 36 positive samples released for research were sequenced and genotyped. Here, the relationship between patient age and viral load as measured by Ct values was measured and determined to be only weakly significant. Consensus sequences for each sample were placed into a global phylogeny and transmission dynamics were investigated, revealing that the closest relative for many samples was from outside of Washington state, indicating mixing of viral pools within geographic regions

Inactivation of the Oxytocin and the Vasopressin (Avp) 1b Receptor Genes, But Not the Avp 1a Receptor Gene, Differentially Impairs the Bruce Effect in Laboratory Mice (Mus musculus)

The Bruce effect is a pheromonally mediated process whereby exposure to chemosensory cues from an unfamiliar male terminates pregnancy in a recently mated female. Pharmacological and genetic evidence implicates both oxytocin (Oxt) and vasopressin (Avp) in the regulation of social memory in males, but less work has been done in females. We tested the extent to which the Avp receptors (Avprs) 1a and 1b and Oxt are essential for the Bruce effect, a phenomenon that relies on olfactory memory. Adult female mice were paired with stimulus males and monitored for the presence of sperm plugs. Wild-type, heterozygous, and homozygous knockout (KO) females for either the Avpr1a, Avpr1b, or Oxt genes were randomly assigned to one of the following treatment groups: 1) alone (mate removed, no second exposure to another animal); 2) paired continuously (mate kept with female for 10–14 d); 3) familiar male (mate removed, reintroduced 24 h later); or 4) unfamiliar male (mate removed, BalbC male introduced 24 h later). Regardless of genotype, 90–100% of females in the alone or paired continuously groups became pregnant. The Oxt KO females terminated their pregnancies regardless of whether their original mate or an unfamiliar male was reintroduced. The Avpr1b KO mice failed to terminate pregnancy in the presence of an unfamiliar male. The Avpr1a KO mice exhibited a normal Bruce effect. These data demonstrate that both Oxt and the Avpr1b are critical for the normal expression of the Bruce effect but have different effects on the interpretation of social cues