Diversity in CO2-Concentrating Mechanisms among Chemolithoautotrophs from the Genera Hydrogenovibrio, Thiomicrorhabdus, and Thiomicrospira, Ubiquitous in Sulfidic Habitats Worldwide.

Members of the genera Hydrogenovibrio, Thiomicrospira, and Thiomicrorhabdus fix carbon at hydrothermal vents, coastal sediments, hypersaline lakes, and other sulfidic habitats. The genome sequences of these ubiquitous and prolific chemolithoautotrophs suggest a surprising diversity of mechanisms for the uptake and fixation of dissolved inorganic carbon (DIC); these mechanisms are verified here. Carboxysomes are apparent in the transmission electron micrographs of most of these organisms but are lacking in Thiomicrorhabdus sp. strain Milos-T2 and Thiomicrorhabdus arctica, and the inability of Thiomicrorhabdus sp. strain Milos-T2 to grow under low-DIC conditions is consistent with the absence of carboxysome loci in its genome. For the remaining organisms, genes encoding potential DIC transporters from four evolutionarily distinct families (Tcr_0853 and Tcr_0854, Chr, SbtA, and SulP) are located downstream of carboxysome loci. Transporter genes collocated with carboxysome loci, as well as some homologs located elsewhere on the chromosomes, had elevated transcript levels under low-DIC conditions, as assayed by reverse transcription-quantitative PCR (qRT-PCR). DIC uptake was measureable via silicone oil centrifugation when a representative of each of the four types of transporter was expressed in Escherichia coli The expression of these genes in the carbonic anhydrase-deficient E. coli strain EDCM636 enabled it to grow under low-DIC conditions, a result consistent with DIC transport by these proteins. The results from this study expand the range of DIC transporters within the SbtA and SulP transporter families, verify DIC uptake by transporters encoded by Tcr_0853 and Tcr_0854 and their homologs, and introduce DIC as a potential substrate for transporters from the Chr family.IMPORTANCE Autotrophic organisms take up and fix DIC, introducing carbon into the biological portion of the global carbon cycle. The mechanisms for DIC uptake and fixation by autotrophic Bacteria and Archaea are likely to be diverse but have been well characterized only for "Cyanobacteria" Based on genome sequences, members of the genera Hydrogenovibrio, Thiomicrospira, and Thiomicrorhabdus have a variety of mechanisms for DIC uptake and fixation. We verified that most of these organisms are capable of growing under low-DIC conditions, when they upregulate carboxysome loci and transporter genes collocated with these loci on their chromosomes. When these genes, which fall into four evolutionarily independent families of transporters, are expressed in E. coli, DIC transport is detected. This expansion in known DIC transporters across four families, from organisms from a variety of environments, provides insight into the ecophysiology of autotrophs, as well as a toolkit for engineering microorganisms for carbon-neutral biochemistries of industrial importance.

Regional adaptation of the education in palliative and end-of-life Care Pediatrics (EPEC-Pediatrics) curriculum in Eurasia.

BACKGROUND: Pediatric palliative care (PPC) is a priority to improve pediatric hematology oncology (PHO) care in Eurasia. However, there are limited regional opportunities for PPC education. We describe the adaptation and implementation of a bilingual end-user Education in Palliative and End-of-Life Care (EPEC)-Pediatrics course for PHO clinicians in Eurasia. METHODS: Due to COVID-19, this course was delivered virtually, consisting of prerecorded, asynchronous lectures, and a bilingual workshop with interactive lectures and small group sessions. A pre-postcourse design was used to evaluate the knowledge acquisition of the participants including their knowledge alignment with World Health Organization (WHO) guidance, ideal timing of palliative care, and comfort in providing palliative care to their patients. Questions were mostly quantitative with multiple choice or Likert scale options, supplemented by free-text responses. RESULTS: A total of 44 (76%) participants from 14 countries completed all components of the course including pre- and postcourse assessments. Participant alignment with WHO guidance improved from 75% in the pre- to 90% in the postcourse assessments (p < 0.001). After participation, 93% felt more confident controlling the suffering of children at the end of life, 91% felt more confident in prescribing opioids and managing pain, and 98% better understood how to hold difficult conversations with patients and families. Most participants (98%) stated that they will change their clinical practice based on the skills and knowledge gained in this course. CONCLUSIONS: We present a successful regional adaptation of the EPEC-Pediatrics curriculum, including novel delivery of course content via a virtual bilingual format. This course resulted in significant improvement in participant attitudes and knowledge of PPC along with an understanding of the ideal timing of palliative care consultation and comfort in providing PPC to children with cancer. We plan to incorporate participant feedback to improve the course and repeat it annually to improve access to high-quality palliative care education for PHO clinicians in Eurasia.