CMF22 Is a Broadly Conserved Axonemal Protein and Is Required for Propulsive Motility in Trypanosoma brucei

ABSTRACT The eukaryotic flagellum (or cilium) is a broadly conserved organelle that provides motility for many pathogenic protozoa and is critical for normal development and physiology in humans. Therefore, defining core components of motile axonemes enhances understanding of eukaryotic biology and provides insight into mechanisms of inherited and infectious diseases in humans. In this study, we show that component of motile flagella 22 (CMF22) is tightly associated with the flagellar axoneme and is likely to have been present in the last eukaryotic common ancestor. The CMF22 amino acid sequence contains predicted IQ and A TPase a ssociated with a variety of cellular a ctivities (AAA) motifs that are conserved among CMF22 orthologues in diverse organisms, hinting at the importance of these domains in CMF22 function. Knockdown by RNA interference (RNAi) and rescue with an RNAi-immune mRNA demonstrated that CMF22 is required for propulsive cell motility in Trypanosoma brucei . Loss of propulsive motility in CMF22-knockdown cells was due to altered flagellar beating patterns, rather than flagellar paralysis, indicating that CMF22 is essential for motility regulation and likely functions as a fundamental regulatory component of motile axonemes. CMF22 association with the axoneme is weakened in mutants that disrupt the nexin-dynein regulatory complex, suggesting potential interaction with this complex. Our results provide insight into the core machinery required for motility of eukaryotic flagella.

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A SAS-6-Like Protein Suggests that the Toxoplasma Conoid Complex Evolved from Flagellar Components

Eukaryotic Cell ◽

10.1128/ec.00096-13 ◽

2013 ◽

Vol 12 (7) ◽

pp. 1009-1019 ◽

Cited By ~ 39

Author(s):

Jessica Cruz de Leon ◽

Nicole Scheumann ◽

Wandy Beatty ◽

Josh R. Beck ◽

Johnson Q. Tran ◽

...

Keyword(s):

Trypanosoma Brucei ◽

Common Ancestor ◽

Coiled Coil ◽

Apicomplexan Parasite ◽

Last Common Ancestor ◽

Cell Cytoplasm ◽

Content Type ◽

Conserved Domain ◽

Coiled Coil Domain ◽

Order Structures

ABSTRACT SAS-6 is required for centriole biogenesis in diverse eukaryotes. Here, we describe a novel family of SAS-6-like (SAS6L) proteins that share an N-terminal domain with SAS-6 but lack coiled-coil tails. SAS6L proteins are found in a subset of eukaryotes that contain SAS-6, including diverse protozoa and green algae. In the apicomplexan parasite Toxoplasma gondii , SAS-6 localizes to the centriole but SAS6L is found above the conoid, an enigmatic tubulin-containing structure found at the apex of a subset of alveolate organisms. Loss of SAS6L causes reduced fitness in Toxoplasma . The Trypanosoma brucei homolog of SAS6L localizes to the basal-plate region, the site in the axoneme where the central-pair microtubules are nucleated. When endogenous SAS6L is overexpressed in Toxoplasma tachyzoites or Trypanosoma trypomastigotes, it forms prominent filaments that extend through the cell cytoplasm, indicating that it retains a capacity to form higher-order structures despite lacking a coiled-coil domain. We conclude that although SAS6L proteins share a conserved domain with SAS-6, they are a functionally distinct family that predates the last common ancestor of eukaryotes. Moreover, the distinct localization of the SAS6L protein in Trypanosoma and Toxoplasma adds weight to the hypothesis that the conoid complex evolved from flagellar components.

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mSphere of Influence: Expanding the CRISPR Sphere with Single-Locus Proteomics

mSphere ◽

10.1128/msphere.00001-20 ◽

2020 ◽

Vol 5 (1) ◽

Cited By ~ 1

Author(s):

Lucy Glover

Keyword(s):

Trypanosoma Brucei ◽

Antigenic Variation ◽

Strand Break ◽

Single Locus ◽

Repair Pathway ◽

Genomic Locus ◽

Content Type ◽

Animal African Trypanosomiasis ◽

Insight Into

ABSTRACT Lucy Glover’s research focuses on the role of DNA repair and recombination in antigenic variation in the parasite Trypanosoma brucei, the causative agent of both human and animal African trypanosomiasis. In this mSphere of Influence article, she reflects on how “A CRISPR-based approach for proteomic analysis of a single genomic locus” by Z. J. Waldrip, S. D. Byrum, A. J. Storey, J. Gao, et al. (Epigenetics 9:1207–1211, 2014, https://doi.org/10.4161/epi.29919) made an impact on her research by taking the precision of CRISPR-Cas9 and repurposing it to look at single-locus proteomics. By using this technology in trypanosomes, Dr. Glover and her colleagues could study the dynamic accumulation of repair proteins after specific damage and gain insight into how the location of a double-strand break (DSB) dictates repair pathway choice and how this may influence immune evasion in these parasites.

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Insight into the Evolution of Magnetotaxis in Magnetospirillum spp., Based onmamGene Phylogeny

Applied and Environmental Microbiology ◽

10.1128/aem.01951-12 ◽

2012 ◽

Vol 78 (20) ◽

pp. 7238-7248 ◽

Cited By ~ 25

Author(s):

Christopher T. Lefèvre ◽

Marian L. Schmidt ◽

Nathan Viloria ◽

Denis Trubitsyn ◽

Dirk Schüler ◽

...

Keyword(s):

16S Rrna ◽

New Genus ◽

Common Ancestor ◽

Rrna Gene ◽

Gene Sequences ◽

16S Rrna Gene Sequences ◽

Bisphosphate Carboxylase ◽

Content Type ◽

Axenic Cultures ◽

Insight Into

ABSTRACTVibrioid- to helical-shaped magnetotactic bacteria phylogenetically related to the genusMagnetospirillumwere isolated in axenic cultures from a number of freshwater and brackish environments located in the southwestern United States. Based on 16S rRNA gene sequences, most of the new isolates represent newMagnetospirillumspecies or new strains of knownMagnetospirillumspecies, while one isolate appears to represent a new genus basal toMagnetospirillum. Partial sequences of conservedmamgenes, genes reported to be involved in the magnetosome and magnetosome chain formation, and form II of the ribulose-1,5-bisphosphate carboxylase/oxygenase gene (cbbM) were determined in the new isolates and compared. ThecbbMgene was chosen for comparison because it is not involved in magnetosome synthesis; it is highly conserved and is present in all but possibly one of the genomes of the magnetospirilla and the new isolates. Phylogenies based on 16S rRNA,cbbM, andmamgene sequences were reasonably congruent, indicating that the genes involved in magnetotaxis were acquired by a common ancestor of theMagnetospirillumclade. However, in one case, magnetosome genes might have been acquired through horizontal gene transfer. Our results also extend the known diversity of theMagnetospirillumgroup and show that they are widespread in freshwater environments.

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Mitochondrial Contact Site and Cristae Organization System and F 1 F O -ATP Synthase Crosstalk Is a Fundamental Property of Mitochondrial Cristae

mSphere ◽

10.1128/msphere.00327-21 ◽

2021 ◽

Author(s):

Lawrence Rudy Cadena ◽

Ondřej Gahura ◽

Brian Panicucci ◽

Alena Zíková ◽

Hassan Hashimi

Keyword(s):

Infectious Diseases ◽

Trypanosoma Brucei ◽

Atp Synthase ◽

Common Ancestor ◽

Fundamental Property ◽

Last Common Ancestor ◽

Contact Site ◽

Content Type ◽

Etiological Agents

Mitochondria have undergone profound diversification in separate lineages that have radiated since the last common ancestor of eukaryotes some eons ago. Most eukaryotes are unicellular protists, including etiological agents of infectious diseases, like Trypanosoma brucei .

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APEX2 Proximity Proteomics Resolves Flagellum Subdomains and Identifies Flagellum Tip-Specific Proteins in Trypanosoma brucei

mSphere ◽

10.1128/msphere.01090-20 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Daniel E. Vélez-Ramírez ◽

Michelle M. Shimogawa ◽

Sunayan S. Ray ◽

Andrew Lopez ◽

Shima Rayatpisheh ◽

...

Keyword(s):

Trypanosoma Brucei ◽

Model Organism ◽

Protein Composition ◽

Principal Component ◽

Protozoan Parasite ◽

Sleeping Sickness ◽

Content Type ◽

Critical Knowledge ◽

Regulatory Complex ◽

And Function

ABSTRACT Trypanosoma brucei is the protozoan parasite responsible for sleeping sickness, a lethal vector-borne disease. T. brucei has a single flagellum (cilium) that plays critical roles in transmission and pathogenesis. An emerging concept is that the flagellum is organized into subdomains, each having specialized composition and function. The overall flagellum proteome has been well studied, but a critical knowledge gap is the protein composition of individual subdomains. We have tested whether APEX-based proximity proteomics could be used to examine the protein composition of T. brucei flagellum subdomains. As APEX-based labeling has not previously been described in T. brucei, we first fused APEX2 to the DRC1 subunit of the nexin-dynein regulatory complex, a well-characterized axonemal complex. We found that DRC1-APEX2 directs flagellum-specific biotinylation, and purification of biotinylated proteins yields a DRC1 “proximity proteome” having good overlap with published proteomes obtained from purified axonemes. Having validated the use of APEX2 in T. brucei, we next attempted to distinguish flagellar subdomains by fusing APEX2 to a flagellar membrane protein that is restricted to the flagellum tip, AC1, and another one that is excluded from the tip, FS179. Fluorescence microscopy demonstrated subdomain-specific biotinylation, and principal-component analysis showed distinct profiles between AC1-APEX2 and FS179-APEX2. Comparing these two profiles allowed us to identify an AC1 proximity proteome that is enriched for tip proteins, including proteins involved in signaling. Our results demonstrate that APEX2-based proximity proteomics is effective in T. brucei and can be used to resolve the proteome composition of flagellum subdomains that cannot themselves be readily purified. IMPORTANCE Sleeping sickness is a neglected tropical disease caused by the protozoan parasite Trypanosoma brucei. The disease disrupts the sleep-wake cycle, leading to coma and death if left untreated. T. brucei motility, transmission, and virulence depend on its flagellum (cilium), which consists of several different specialized subdomains. Given the essential and multifunctional role of the T. brucei flagellum, there is need for approaches that enable proteomic analysis of individual subdomains. Our work establishes that APEX2 proximity labeling can, indeed, be implemented in the biochemical environment of T. brucei and has allowed identification of proximity proteomes for different flagellar subdomains that cannot be purified. This capacity opens the possibility to study the composition and function of other compartments. We expect this approach may be extended to other eukaryotic pathogens and will enhance the utility of T. brucei as a model organism to study ciliopathies, heritable human diseases in which cilium function is impaired.

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Rethinking bibliographic utilities for library consortia

Library Hi Tech News ◽

10.1108/lhtn-02-2020-0014 ◽

2020 ◽

Vol 37 (8) ◽

pp. 7-9

Author(s):

Israel Odede

Keyword(s):

Literature Review ◽

Paradigm Shift ◽

Design Methodology ◽

Distributed Network ◽

Network Resources ◽

Content Type ◽

Library Consortia ◽

Individual Ownership ◽

Insight Into

Purpose The paper aims to critically examine the bibliographic utility as a roadmap to increase library consortia and provide an insight into a new library consortia strategy that integrates librarians into a system of sharing both resources and knowledge. Design/methodology/approach This study adopted a literature review approach with a focus on bibliographic utility as a necessary prerequisite for effective library consortia, which is a paradigm shift from the concept of individual ownership to a collective access of distributed network resources and knowledge. Findings The reviewed literature indicated that significant bibliographic utilities and integrated library systems are factors that shaped and developed consortia activities in libraries. Originality/value The bibliographic utility has limited literature, and a few published scholarly studies have combined bibliographic utility and library consortia as strategies to share resources and knowledge

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Formation of contracts for the international sale of goods under Korean law and the CISG

Journal of Korea Trade ◽

10.1108/jkt-06-2017-0058 ◽

2017 ◽

Vol 21 (3) ◽

pp. 208-223

Author(s):

Byung Mun Lee

Keyword(s):

Comparative Study ◽

Design Methodology ◽

Case Law ◽

The Other ◽

Basic Question ◽

Content Type ◽

International Sale Of Goods ◽

The Comparative Study ◽

International Sales ◽

Insight Into

Purpose The purpose of this paper is to describe and analyze the rules on the formation of contracts under Korean law and the Contracts for the International Sale of Goods (CISG) in a comparative way and introduce the relevant proposed rules under the Amendment Draft of the Korean Civil Code (KCC). In addition, it attempts to compare and evaluate them in light of the discipline of comparative law. Design/methodology/approach In order to achieve the purposes of the study, it executes a comparative study of the rules as to the formation of contracts of the CISG, Korean law and the Amendment Draft of the KCC. The basic question for this comparative study is placed on whether a solution from one jurisdiction is more logical than the others and to what extent each jurisdiction has responded to protect the reasonable expectations of the parties in the rules as to the formation of contracts. Findings The comparative study finds that most of the rules under the CISG are quite plausible and logical and they are more or less well reflected in the proposals advanced by the KCC amendment committee. On the other hand, the other rules under the CISG which have brought criticisms in terms of their complexity and inconsistent case law invite us their revision or consistent interpretation. The drawbacks of the CISG have also been well responded in the Amendment Draft of the KCC. Nevertheless, it is quite unfortunate that the Amendment Draft of the KCC still has a rule that regards any purported performance with non-material alteration of the terms of an offer as an acceptance. Originality/value This study may provide legal and practical advice to both the seller and the buyer when they enter into a contract for international sales of goods. In addition, it may render us an insight into newly developed or developing rules in this area and show us how they interact with each other. Furthermore, it may be particularly useful in Korea where there is an ongoing discussion for revision of the KCC.

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Professionals freaking out: the case of accreditation in Dutch higher education

The TQM Journal ◽

10.1108/17542730910983399 ◽

2009 ◽

Vol 21 (5) ◽

pp. 473-485 ◽

Cited By ~ 3

Author(s):

Everard van Kemenade ◽

Teun W. Hardjono

Keyword(s):

The Netherlands ◽

Design Methodology ◽

Iso 9000 ◽

Preliminary Survey ◽

External Evaluation ◽

Content Type ◽

Evaluation Systems ◽

System A ◽

Engineering And Technology ◽

Insight Into

PurposeThe purpose of this paper is to define what factors cause willingness and/or resistance among lecturers in universities towards external evaluation systems, especially accreditation.Design/methodology/approachA model has been designed to describe possible factors of willingness and/or resistance towards accreditation based on Ajzen and Metselaar. A literature review has been undertaken on the effects of external evaluation like ISO 9000 as well as accreditation systems such as Accreditation Board for Engineering and Technology and European Quality Improvement System. A questionnaire has been administered to a group of 63 lecturers from three departments at Fontys University in The Netherlands. The results of this preliminary survey have been presented to 1,500 academics in The Netherlands and Flanders to collect empirical data.FindingsResistance to accreditation can be found in the consequences of accreditation for the work of the lecturer (workload), negative emotions (stress and insecurity); the lack of knowledge and experience (help from specialists is needed); and lack of acceptance (other paradigm).Originality/valueThe paper provides more insight into the difficulties that organizations, especially universities, have to commit their employees to external evaluation. It might be possible to generalize the findings to other professionals in other organizations. Little research in this field has been undertaken so far.

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The future of financial markets and regulation: what strategy for Europe?

foresight ◽

10.1108/fs-05-2012-0039 ◽

2014 ◽

Vol 16 (2) ◽

pp. 95-108 ◽

Cited By ~ 4

Author(s):

Jean-Baptiste Gossé ◽

Dominique Plihon

Keyword(s):

Financial Markets ◽

Capital Market ◽

Financial Stability ◽

Design Methodology ◽

Financial Integration ◽

Content Type ◽

Realistic Option ◽

The Future ◽

Unstable Environment ◽

Insight Into

Purpose – This article aims to provide insight into the future of financial markets and regulation in order to define what would be the best strategy for Europe. Design/methodology/approach – First the authors define the potential changes in financial markets and then the tools available for the regulator to tame them. Finally, they build five scenarios according to the main evolutions observed on the financial markets and on the tools used by the regulator to modify these trends. Findings – Among the five scenarios defined, two present highly unstable features since the regulator refuses to choose between financial opening and independently determining how to regulate finance in order to preserve financial stability. Three of them achieve financial stability. However, they are more or less efficient or feasible. In terms of market efficiency, the multi-polar scenario is the best and the fragmentation scenario is the worst, since gains of integration depend on the size of the new capital market. Regarding sovereignty of regulation, fragmentation is the best scenario and the multi-polar scenario is the worst, because it necessitates coordination at the global level which implies moving further away from respective national preferences. However, the more realistic option seems to be the regionalisation scenario: this level of coordination seems much more realistic than the global one; the market should be of sufficient size to enjoy substantial benefits of integration. Nevertheless, the “European government” might gradually increase the degree of financial integration outside Europe in line with the degree of cooperation with the rest of the world. Originality/value – Foresight studies on financial markets and regulation are quite rare. This may be explained by the difficulty to forecast what will be their evolution in the coming decades, not least because finance is fundamentally unstable. This paper provides a framework to consider what could be the best strategy of regulators in such an unstable environment.

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Correlation between sustainability education and engineering students’ attitudes towards sustainability

International Journal of Sustainability in Higher Education ◽

10.1108/ijshe-08-2017-0139 ◽

2018 ◽

Vol 19 (3) ◽

pp. 459-472 ◽

Cited By ~ 16

Author(s):

Kuok Ho Daniel Tang

Keyword(s):

Sustainable Development ◽

Design Methodology ◽

Engineering Students ◽

Sustainability Education ◽

Content Type ◽

Fundamental Knowledge ◽

Students Attitudes ◽

Development Course ◽

Beliefs And Attitudes ◽

Insight Into

Purpose The purpose of this study is to investigate the impacts of a sustainable development course on the beliefs, attitudes and intentions of a cohort of engineering students in a university in Miri, Malaysia, towards sustainability. Design/methodology/approach Questionnaire survey was conducted among the cohort of students encompassing the three facets mentioned. Findings The respondents expressed low to medium agreement towards all the survey items related to beliefs, attitudes and intentions. A sense of moral obligation towards sustainability is linked to higher sustainability awareness, willingness to safeguard sustainability and a sense of responsibility towards sustainable development. The respondents were generally perceived to have fundamental knowledge of sustainable development. Research limitations/implications This study shows that a sustainable development course called Engineering Sustainable Development offered in a university in Miri, produced positive impacts on the beliefs, attitudes and intentions of the engineering students towards sustainable development. Sustainable development courses are generally instrumental to impart the value and practices of sustainability among university students. Originality/value As limited correlational studies on whether sustainable development courses effectively shape the beliefs and attitudes of students have been previously conducted, this study provides insight into the effectiveness of one of such courses and how the course can be further improved to enhance its effectiveness.

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