Archaea

SummaryA headline on the front page of the New York Times for November 3, 1977, read “Scientists Discover a Way of Life That Predates Higher Organisms”. The accompanying article described a spectacular claim by Carl Woese and George Fox to have discovered a third form of life, a new ‘domain’ that we now call Archaea. It’s not that these microbes were unknown before, nor was it the case that their peculiarities had gone completely unnoticed. Indeed, Ralph Wolfe, in the same department at the University of Illinois as Woese, had already discovered how it was that methanogens (uniquely on the planet) make methane, and the bizarre adaptations that allow extremely halophilic archaea (then called halobacteria) and thermoacidophiles to live in the extreme environments where they do were already under investigation in many labs. But what Woese and Fox had found was that these organisms were related to each other not just in their ‘extremophily’ but also phylogenetically. And, most surprisingly, they were only remotely related to the rest of the prokaryotes, which we now call the domain Bacteria (Figure 1)

Impact Of Inter-Professional Education On Nursing Student Outcomes In The Online Environment

The implementation and integration of inter-professional education (IPE) into a curriculum is supported by the National Council of State Boards of Nursing (NCSBN), the Inter-professional Education Collaborative (IPEC), and the Institute of Medicine’s (IOM) Future of Nursing report. While there is support for implementation, there is a lack of data and guidelines which to follow currently. The purpose of this nursing research study was to investigate the impact of inter-professional collaboration on nursing student outcomes in the online environment. A co-teaching model was implemented within an online environment to provide inter-professionally lead nursing sciences courses to nursing students in a baccalaureate program. In the four sessions following the implementation of interdisciplinary collaborative teaching, 605 students completed the courses with 179 submitting the end of course survey. Results indicated that the overall student satisfaction rating with the pathophysiology online course was significant at p < 0.05 following the implementation of inter-professional teaching methodology. Prior to implementation of collaborative teaching, the total enrollment in pathophysiology was 194. After the institution of collaborative teaching, the total student enrollment was 605. This reflected a significant increase in student enrollment of 311%. Today, the complex healthcare delivery system necessitates a shift from traditional education to an inter-professional collaborative teaching model that generates knowledge from interaction with a variety of educators from a variety of disciplines (Hean, Craddock, & Hammick, 2012). Nursing curricula is needed which fosters both an inter-professional learning of shared knowledge and the discipline-specific learning essential for professional practice.

Enhancing The Learning Environment Of Nursing Students Through Interprofessional Collaboration

The AACN position statement (1999) supports interprofessional collaboration. The development of innovative collaborative teaching methods within education may enhance the learning environment of students. Educational institutions utilize student evaluations as a method of listening to the voices of students, but research related to their use is limited. The purpose of this study was to explore the impact of interprofessional collaboration on nursing students’ perceptions of the online learning environment. An innovative collaborative teaching methodology was developed using a variety of disciplines, including physicians, pharmacists, chiropractic physicians, and nurses. Quantitative data analyses indicated a significant increase in student satisfaction with the online course as well as the online environment p < 0.05 following the establishment of the collaborative teaching methodology. Qualitative analysis illustrated enhanced satisfaction among students following the institution of interprofessional collaboration. Findings that view the learning environment through the lens of students’ eyes have many implications, including increased student and faculty satisfaction with the teaching/learning experience and enhanced collaboration among healthcare professionals. In addition, results may impact the curriculum by identifying a multidisciplinary approach to nursing education as an important resource. If we believe that students have a right to be active participants in their educational experiences, then we must give voice to their values, choices, concerns, and requests. A collaborative teaching methodology is one way to ensure that students’ voices are heard and acted upon, and it was found to be an innovative solution in meeting enrollment demands and healthcare needs. Collaborative relationships within nursing practice and nursing education are essential in the preparation of future nurses.

Chapter 21 Archaea

Practical Handbook of Microbiology, 4th edition provides basic, clear and concise knowledge and practical information about working with microorganisms. Useful to anyone interested in microbes, the book is intended to especially benefit four groups: trained microbiologists working within one specific area of microbiology; people with training in other disciplines, and use microorganisms as a tool or "chemical reagent"; business people evaluating investments in microbiology focused companies; and an emerging group, people in occupations and trades that might have limited training in microbiology, but who require specific practical information

Chapter 21 Archaea

Practical Handbook of Microbiology, 4th edition provides basic, clear and concise knowledge and practical information about working with microorganisms. Useful to anyone interested in microbes, the book is intended to especially benefit four groups: trained microbiologists working within one specific area of microbiology; people with training in other disciplines, and use microorganisms as a tool or "chemical reagent"; business people evaluating investments in microbiology focused companies; and an emerging group, people in occupations and trades that might have limited training in microbiology, but who require specific practical information

A closed Candidatus Odinarchaeum chromosome exposes Asgard archaeal viruses

Asgard archaea have recently been identified as the closest archaeal relatives of eukaryotes. Their ecology, and particularly their virome, remain enigmatic. We reassembled and closed the chromosome of Candidatus Odinarchaeum yellowstonii LCB_4, through long-range PCR, revealing CRISPR spacers targeting viral contigs. We found related viruses in the genomes of diverse prokaryotes from geothermal environments, including other Asgard archaea. These viruses open research avenues into the ecology and evolution of Asgard archaea

Nephromyces Represents a Diverse and Novel Lineage of the Apicomplexa That Has Retained Apicoplasts

A most interesting exception within the parasitic Apicomplexa is Nephromyces, an extracellular, probably mutualistic, endosymbiont found living inside molgulid ascidian tunicates (i.e., sea squirts). Even though Nephromyces is now known to be an apicomplexan, many other questions about its nature remain unanswered. To gain further insights into the biology and evolutionary history of this unusual apicomplexan, we aimed to 1) find the precise phylogenetic position of Nephromyces within the Apicomplexa, 2) search for the apicoplast genome of Nephromyces, and 3) infer the major metabolic pathways in the apicoplast of Nephromyces. To do this, we sequenced a metagenome and a metatranscriptome from the molgulid renal sac, the specialized habitat where Nephromyces thrives. Our phylogenetic analyses of conserved nucleus-encoded genes robustly suggest that Nephromyces is a novel lineage sister to the Hematozoa, which comprises both the Haemosporidia (e.g., Plasmodium) and the Piroplasmida (e.g., Babesia and Theileria). Furthermore, a survey of the renal sac metagenome revealed 13 small contigs that closely resemble the genomes of the nonphotosynthetic reduced plastids, or apicoplasts, of other apicomplexans. We show that these apicoplast genomes correspond to a diverse set of most closely related but genetically divergent Nephromyces lineages that co-inhabit a single tunicate host. In addition, the apicoplast of Nephromyces appears to have retained all biosynthetic pathways inferred to have been ancestral to parasitic apicomplexans. Our results shed light on the evolutionary history of the only probably mutualistic apicomplexan known, Nephromyces, and provide context for a better understanding of its life style and intricate symbiosis

Chlamydial contribution to anaerobic metabolism during eukaryotic evolution

The origin of eukaryotes is a major open question in evolutionary biology. Multiple hypotheses posit that eukaryotes likely evolved from a syntrophic relationship between an archaeon and an alphaproteobacterium based on H-2 exchange. However, there are no strong indications that modern eukaryotic H-2 metabolism originated from archaea or alphaproteobacteria. Here, we present evidence for the origin of H-2 metabolism genes in eukaryotes from an ancestor of the Anoxychlamydiales-a group of anaerobic chlamydiae, newly described here, from marine sediments. Among Chlamydiae, these bacteria uniquely encode genes for H-2 metabolism and other anaerobiosis-associated pathways. Phylogenetic analyses of several components of H-2 metabolism reveal that Anoxychlamydiales homologs are the closest relatives to eukaryotic sequences. We propose that an ancestor of the Anoxychlamydiales contributed these key genes during the evolution of eukaryotes, supporting a mosaic evolutionary origin of eukaryotic metabolism

Inference and reconstruction of the heimdallarchaeial ancestry of eukaryotes

In the ongoing debates about eukaryogenesis—the series of evolutionary events leading to the emergence of the eukaryotic cell from prokaryotic ancestors— members of the Asgard archaea play a key part as the closest archaeal relatives of eukaryotes1. However, the nature and phylogenetic identity of the last common ancestor of Asgard archaea and eukaryotes remain unresolved2–4. Here we analyse distinct phylogenetic marker datasets of an expanded genomic sampling of Asgard archaea and evaluate competing evolutionary scenarios using state-of-the-art phylogenomic approaches. We find that eukaryotes are placed, with high confidence, as a well-nested clade within Asgard archaea and as a sister lineage to Hodarchaeales, a newly proposed order within Heimdallarchaeia. Using sophisticated gene tree and species tree reconciliation approaches, we show that analogous to the evolution of eukaryotic genomes, genome evolution in Asgard archaea involved significantly more gene duplication and fewer gene loss events compared with other archaea. Finally, we infer that the last common ancestor of Asgard archaea was probably a thermophilic chemolithotroph and that the lineage from which eukaryotes evolved adapted to mesophilic conditions and acquired the genetic potential to support a heterotrophic lifestyle. Our work provides key insights into the prokaryote-to-eukaryote transition and a platform for better understanding the emergence of cellular complexity in eukaryotic cells

Prevalence and determinants of oral health conditions and treatment needs among slum and non-slum urban residents : evidence from Nigeria

Oral diseases constitute a neglected epidemic in Low and Middle-Income Countries (LMICs). An understanding of its distribution and severity in different settings can aid the planning of preventive and therapeutic services. This study assessed the oral health conditions, risk factors, and treatment needs among adult residents in the slum and compared findings with non-slum urban residents in Ibadan, Nigeria. The Multistage sampling was used to select adult (≥18-years) residents from a slum and a non-slum urban sites. Information sought from participants included dietary habits, oral hygiene practices, and the use of dental services. Oral examinations were performed in line with WHO guidelines. Associations were examined using logistic regression. Mediation analysis was undertaken using generalized structural equation modeling. The sample comprised 678 slum and 679 non-slum residents. Median age in slum vs non-slum was 45 (IQR:32–50) versus 38 (IQR:29–50) years. Male: female ratio was 1:2 in both sites. Prevalence of oral diseases (slum vs non-slum sites): dental caries (27% vs 23%), gingival bleeding (75% vs 53%) and periodontal pocket (23% vs 16%). The odds of having dental caries were 21% higher for the slum dwellers compared to non-slum residents (OR = 1.21, 95% CI:0.94 to 1.56); and 50% higher for periodontal pocket (OR = 1.50, 95%CI: 1.13 to 1.98), after adjusting for age and sex. There was little evidence that tooth cleaning frequency mediated the relationship between place of residence and caries (OR = 0.95, 95%CI: 0.87 to 1.03 [indirect effect], 38% mediated) or periodontal pocket (OR = 0.95, 95%CI: 0.86 to 1.04, 15% mediated). Thirty-five percent and 27% of residents in the slum and non-slum sites respectively required the “prompt and urgent” levels of treatment need. Oral diseases prevalence in both settings are high and the prevalence was generally higher in the slum with correspondingly higher levels of prompt and urgent treatment needs. Participants may benefit from targeted therapeutic and health promotion intervention services