Invertebrate acetylcholinesterases: Insights into their evolution and non-classical functions

Acetylcholinesterase (AChE) plays a pivotal role in synaptic transmission by hydrolyzing the neurotransmitter acetylcholine. In addition to the classical function of AChE in synaptic transmission, various non-classical functions have been elucidated. Unlike vertebrates possessing a single AChE gene (ace), invertebrates (nematodes, arachnids, and insects) have multiple ace loci, encoding diverse AChEs with a range of different functions. In the field of toxicology, AChE with synaptic function has long been exploited as the target of organophosphorus and cabarmate pesticides to control invertebrate pests for the past several decades. However, many aspects of the evolution and non-classical roles of invertebrate AChEs are still unclear. Although currently available information on invertebrate AChEs is fragmented, we reviewed the recent findings on their evolutionary status, molecular/biochemical properties, and deduced non-classical (non-neuronal) functions.     

Insights into the quality of DnaA boxes and their cooperativity

Plasmids carrying the mioC promoter region with its two DnaA boxes are as efficient in titration of DnaA protein as plasmids carrying a replication-inactivated oriC region with its five DnaA boxes. The two DnaA boxes upstream of the mioC promoter were mutated in various ways to study the cooperativity between the DnaA boxes, and to study in vivo the in vitro-defined 9mer DnaA box consensus sequence (TT(A)/(T)TNCACA). The quality and cooperativity of the DnaA boxes were determined in two complementary ways: as titration of DnaA protein leading to derepression of the dnaA promoter, and as repression of the mioC promoter caused by the DnaA protein binding to the DnaA boxes. Titration of DnaA protein correlated with repression of the mioC promoter. The level of titration and repression with the normal promoter-proximal box (TTTTCCACA) depends strongly on the presence and the quality of a DnaA box in the promoter-distal position, whereas a promoter-proximal DnaA box with the sequence TTATCCACA titrated DnaA protein and caused significant repression of the mioC promoter without a promoter-distal DnaA box. The quality of the eight different consensus DnaA boxes located in the promoter-proximal position was determined: TTATCCACA had the highest affinity for DnaA protein. In the third position, A was better than T, and the four possibilities in the fifth position could be ranked as C >A >or=G >T. Parallel in vitro experiments using a purified DNA-binding domain of DnaA protein gave the same ranking of the binding affinities of the eight DnaA boxes.     

Immunogenic cell death modalities and their impact on cancer treatment

It is still enigmatic under which circumstances cellular demise induces an immune response or rather remains immunologically silent. Moreover, the question remains open under which circumstances apoptotic, autophagic or necrotic cells are immunogenic or tolerogenic. Although apoptosis appears to be morphologically homogenous, recent evidence suggests that the pre-apoptotic surface-exposure of calreticulin may dictate the immune response to tumor cells that succumb to anticancer treatments. Moreover, the release of high-mobility group box 1 (HMGB1) during late apoptosis and secondary necrosis contributes to efficient antigen presentation and cytotoxic T-cell activation because HMGB1 can bind to Toll like receptor 4 on dendritic cells, thereby stimulating optimal antigen processing. Cell death accompanied by autophagy also may facilitate cross priming events. Apoptosis, necrosis and autophagy are closely intertwined processes. Often, cells manifest autophagy before they undergo apoptosis or necrosis, and apoptosis is generally followed by secondary necrosis. Whereas apoptosis and necrosis irreversibly lead to cell death, autophagy can clear cells from stress factors and thus facilitate cellular survival. We surmise that the response to cellular stress like chemotherapy or ionizing irradiation, dictates the immunological response to dying cells and that this immune response in turn determines the clinical outcome of anticancer therapies. The purpose of this review is to summarize recent insights into the immunogenicity of dying tumor cells as a function of the cell death modality.     

Physiological and morphological characterisation of Limonium species in their natural habitats: Insights into their abiotic stress responses

Background and aims

Morphological and biochemical traits of four halophytes of the genus Limonium were analysed in plants sampled from salt marshes in SE Spain. This work aimed to explore the mechanism(s) behind the adaptation of these species to stressful habitats, with particular emphasis on responses to drought.

Methods

Plants of each species together with soil samples were collected in summer, which is the most stressful season in the Mediterranean. Soil parameters and plant morphological traits were determined, and the levels of several biochemical stress markers in plants were measured using spectrophotometric assays. A multivariate analysis was performed to correlate soil and plant data.

Results

Morphological characteristics regarding the underground system topology and several biochemical traits (higher foliar Ca²⁺, sucrose and glucose, and lower proline, glycine-betaine and fructose) clearly separate L. santapolense individuals from plants of the other three species.

Conclusions

Drought tolerance of L. santapolense in the field is mostly dependent on morphological adaptations: when growing in an arid location, plants of this species develop long taproots that can extract water from the deep, moist layers of the soil.

     

Insights into the genomic features and evolutionary impact of the genes configuring duplicated pseudogenes in human

Pseudogenes, regarded as ‘genomic fossils’, are DNA sequences resembling functional genes in perspective of sequence homology but completely non-functional. In this study, we explored the unique characteristic features of human genes, configuring classical duplicated pseudogenes. We found that progenitors of duplicated pseudogenes are characterized by a high expressivity, and ability to encode hub-proteins in association with a high evolutionary rate. Such unusual features are endorsed by longer protein length, elevated CpG content, and a high recombination rate. The non-functionalization of their duplicated copies can be attributed to the overabundance of gene paralog number in concert with functional redundancy.     

Insights into prion strains and neurotoxicity

Transmissible spongiform encephalopathies (TSEs) are neurodegenerative diseases that are caused by prions and affect humans and many animal species. It is now widely accepted that the infectious agent that causes TSEs is PrP(Sc), an aggregated moiety of the host-derived membrane glycolipoprotein PrP(C). Although PrP(C) is encoded by the host genome, prions themselves encipher many phenotypic TSE variants, known as prion strains. Prion strains are TSE isolates that, after inoculation into distinct hosts, cause disease with consistent characteristics, such as incubation period, distinct patterns of PrP(Sc) distribution and spongiosis and relative severity of the spongiform changes in the brain. The existence of such strains poses a fascinating challenge to prion research.     

Insights into eisosome assembly and organization

Eisosomes, large protein complexes that are predominantly composed of BAR-domain-containing proteins Pil1 and its homologs, are situated under the plasma membrane of ascomycetes. A successful targeting of Pil1 onto the future site of eisosome accompanies maturation of eisosome. During or after recruitment, Pil1 undergoes self-assembly into filaments that can serve as scaffolds to induce membrane furrows or invaginations. Although a consequence of the invagination is likely to redistribute particular proteins and lipids to a different location, the precise physiological role of membrane invagination and eisosome assembly awaits further investigation. The present review summarizes recent research findings within the field regarding the detailed structural and functional significance of Pil1 on eisosome organization.     

Insights into ABC Transport in Archaea

In archaea, ATP-binding cassette (ABC) transporters play a crucial role in substrate uptake, export, and osmoregulation. Archael substrate-binding-protein-dependent ABC transporters are equipped with a very high affinity for their cognate substrates which provide these organisms with the ability to efficiently scavenge substrates from their environment even when present only at low concentration. Further adaptations to the archaeal way of life are especially found in the domain organization and anchoring of the substrate-binding proteins to the membrane. Examination of the signal peptides of binding proteins of 14 archael genomes showed clear differences between euryarchaeotes and crenarchaeotes. Furthermore, a profiling and comparison of ABC transporters in the three sequenced pyrococcal strains was performed.     

Insights into the pathogenesis and treatment of cancer from inborn errors of metabolism

Mutations in genes that play fundamental roles in metabolic pathways have been found to also play a role in tumor development and susceptibility to cancer. At the same time, significant progress has been made in the treatment of patients with inborn errors of metabolism (IEM),(1) resulting in increased longevity and the unmasking of cancer predisposition, frequently hepatocellular carcinoma, in these conditions. These patients offer a potential opportunity to deepen our understanding of how intermediary metabolism impacts tumorigenesis. We provide an overview from the perspective of cancers in patients affected with IEM and discuss how dysregulation of these specific metabolic pathways might contribute to the mechanisms of cancer development and treatment.     

The impact of insomnia and sleep disturbances on depression and suicidality.

Previous research has demonstrated an association between suicidality and sleep, suggesting that sleep disturbances may exacerbate mood dysregulation in participants suffering from mood disorders. The purpose of this study was to investigate the impact of sleep disturbances and insomnia on depression and suicidality in a nontreatment seeking sample of college students. Results indicated that insomnia and nightmares were significant predictors of symptoms of depression, while only nightmares significantly predicted suicidal ideation. Further analysis indicated that participants with elevated scores on insomnia, nightmares, or both experienced differing levels of depression and suicidal ideation. Future directions and treatment implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Insights into the impact and use of research results in a residential long-term care facility: a case study

Background

Quality improvement collaboratives (QICs) bring together groups of healthcare professionals to work in a structured manner to improve the quality of healthcare delivery within particular domains. We explored which characteristics of the composition, participation, functioning, and organization of these collaboratives related to changes in the healthcare for patients with anxiety disorders, dual diagnosis, or schizophrenia.

Methods

We studied three QICs involving 29 quality improvement (QI) teams representing a number of mental healthcare organizations in the Netherlands. The aims of the three QICs were the implementation of multidisciplinary practice guidelines in the domains of anxiety disorders, dual diagnosis, and schizophrenia, respectively. We used eight performance indicators to assess the impact of the QI teams on self-reported patient outcomes and process of care outcomes for 1,346 patients. The QI team members completed a questionnaire on the characteristics of the composition, participation in a national program, functioning, and organizational context for their teams. It was expected that an association would be found between these team characteristics and the quality of care for patients with anxiety disorders, dual diagnosis, and schizophrenia.

Results

No consistent patterns of association emerged. Theory-based factors did not perform better than practice-based factors. However, QI teams that received support from their management and both active and inspirational team leadership showed better results. Rather surprisingly, a lower average level of education among the team members was associated with better results, although less consistently than the management and leadership characteristics. Team views with regard to the QI goals of the team and attitudes towards multidisciplinary practice guidelines did not correlate with team success.

Conclusions

No general conclusions about the impact of the characteristics of QI teams on the quality of healthcare can be drawn, but support of the management and active, inspirational team leadership appear to be important. Not only patient outcomes but also the performance indicators of monitoring and screening/assessment showed improvement in many but not all of the QI teams with such characteristics. More studies are needed to identify factors associated with the impact of multidisciplinary practice guidelines in mental healthcare.     

Insights into the impact and use of research results in a residential long-term care facility: a case study

ABSTRACT: BACKGROUND: Engaging end users of research in the process of disseminating findings may increase the relevance of findings and their impact for users. We report findings from a case study that explored how involvement with the Translating Research in Elder Care (TREC) study influenced management and staff at one of 36 TREC facilities. We conducted the study at 'Restwood' (pseudonym) nursing home because the Director of Care engaged actively in the study and TREC data showed that this site differed on some areas from other nursing homes in the province. The aims of the case study were two-fold: to gain a better understanding of how frontline staff engage with the research process, and to gain a better understanding of how to share more detailed research results with management. METHODS: We developed an Expanded Feedback Report for use during this study. In it, we presented survey results that compared Restwood to the best performing site on all variables and participating sites in the province. Data were collected regarding the Expanded Feedback Report through interviews with management. Data from staff were collected through interviews and observation. We used content analysis to derive themes to describe key aspects related to the study aims. RESULTS: We observed the importance of understanding organizational routines and the impact of key events in the facility's environment. We gleaned additional information that validated findings from prior feedback mechanisms within TREC. Another predominant theme was the sense that the opportunity to engage in a research process was reaffirming for staff (particularly healthcare aides)--what they did and said mattered, and TREC provided a means of having one's voice heard. We gained valuable insight from the Director of Care about how to structure and format more detailed findings to assist with interpretation and use of results. CONCLUSIONS: Four themes emerged regarding staff engagement with the research process: sharing feedback reports from the TREC study; the meaning of TREC to staff; understanding organizational context; and using the study feedback for improvement at Restwood. This study has lessons for researchers on how to share research results with study participants, including management.     

Biochemical and Genetic Insights into Asukamycin Biosynthesis

Asukamycin, a member of the manumycin family metabolites, is an antimicrobial and potential antitumor agent isolated from Streptomyces nodosus subsp. asukaensis. The entire asukamycin biosynthetic gene cluster was cloned, assembled, and expressed heterologously in Streptomyces lividans. Bioinformatic analysis and mutagenesis studies elucidated the biosynthetic pathway at the genetic and biochemical level. Four gene sets, asuA–D, govern the formation and assembly of the asukamycin building blocks: a 3-amino-4-hydroxybenzoic acid core component, a cyclohexane ring, two triene polyketide chains, and a 2-amino-3-hydroxycyclopent-2-enone moiety to form the intermediate protoasukamycin. AsuE1 and AsuE2 catalyze the conversion of protoasukamycin to 4-hydroxyprotoasukamycin, which is epoxidized at C5–C6 by AsuE3 to the final product, asukamycin. Branched acyl CoA starter units, derived from Val, Leu, and Ile, can be incorporated by the actions of the polyketide synthase III (KSIII) AsuC3/C4 as well as the cellular fatty acid synthase FabH to produce the asukamycin congeners A2–A7. In addition, the type II thioesterase AsuC15 limits the cellular level of ω-cyclohexyl fatty acids and likely maintains homeostasis of the cellular membrane.     

Insights into physiological and genetic mupirocin susceptibility in bifidobacteria

Mupirocin is an antibiotic commonly used in selective media for the isolation of bifidobacteria. However, little is known about the genetic traits responsible for bifidobacterial resistance to mupirocin. Our investigation demonstrates that all of the bifidobacteria tested exhibit a phenotype of generally high resistance to this antibiotic. The genotypic reason for bifidobacterial mupirocin resistance was further characterized by sequencing of the isoleucyl-tRNA synthetase gene (ileS) coupled with three-dimensional modeling of the encoded protein and cloning of the ileS gene of Bifidobacterium bifidum PRL2010 in a mupirocin-sensitive Escherichia coli strain. These analyses revealed key amino acid residues of the IleS protein that apparently are crucial for conferring a mupirocin resistance phenotype to bifidobacteria.