Phenotypic influences on the reproductive strategy of the facultative sexual rotifer <Emphasis Type="Italic">Brachionus rubens</Emphasis> (Monogononta)

Facultative sexual species employ a dual reproductive strategy (heterogony) comprising primarily asexual reproduction with intermittent sexual reproduction. Given the higher relative costs of sexual reproduction, elucidating the triggers underlying these transitions might help our understanding of the evolution of (obligate) sex in general. Existing hypotheses into how and when facultative sexuals invest into sex focus largely either on environmental (habitat-deterioration and resource-demanding hypotheses) or genetic factors (condition-dependent hypothesis), but tend to lack experimental evidence, especially with respect to within-population variation. To address this deficit, we examined the influence of several variables that potentially affect fitness (food quality, water temperature, physiological acclimation, and all combinations thereof) on both the lifetime reproduction (total number of offspring) and investment into sexual offspring per female in a clonal population of the monogonont rotifer Brachionus rubens. Investment into sex, both absolutely and relative to lifetime reproduction, was tied most closely to and positively correlated with individual fitness (i.e., lifetime reproduction): individuals with higher fitness invested more into sexual reproduction. These results run contra to the condition-dependent hypothesis and indicate an energy-budget analogue of the resource-demanding hypothesis. Furthermore, investment into sex increased after a period of physiological acclimation to the new conditions, probably because of the amelioration of short-term stress effects or clonal selection. Our results underscore that life history and general phenotypic considerations—here, energetic provisioning of offspring, the presence of a sexual resting stage, and the relative timing of sexual versus asexual reproduction—can modify existing hypotheses based either on environmental or genetic factors alone.     

Composition of the central stalk of the Na+-pumping V-ATPase from Caloramator fervidus

The Na⁺-pumping V-ATPase complex of the thermophilic bacterium Caloramator fervidus was purified and dissociated under controlled conditions. The structure of purified V₁-ATPase subcomplexes differing in subunit composition was analyzed by electron microscopy and single particle analysis of 50 000 projections. Difference mapping of subcomplex projections revealed the presence and position of two subunits in the central stalk. A density with an elongated shape similar to the γ subunit of F-ATPases is partly located within V₁ and corresponds, most likely, to subunit E. Subunit E is connected to the membrane-bound part V₀ via subunit C, a spherical density that is connected to the center of V₀. The presence of subunit C makes the central stalk substantially longer in comparison to the F-ATPases, in which the γ subunit connects directly to F₀.     

The GIT family of proteins forms multimers and associates with the presynaptic cytomatrix protein Piccolo

The cytoskeletal matrix assembled at active zones (CAZ) is implicated in defining neurotransmitter release sites. However, little is known about the molecular mechanisms by which the CAZ is organized. Here we report a novel interaction between Piccolo, a core component of the CAZ, and GIT proteins, multidomain signaling integrators with GTPase-activating protein activity for ADP-ribosylation factor small GTPases. A small region (approximately 150 amino acid residues) in Piccolo, which is not conserved in the closely related CAZ protein Bassoon, mediates a direct interaction with the Spa2 homology domain (SHD) domain of GIT1. Piccolo and GIT1 colocalize at synaptic sites in cultured neurons. In brain, Piccolo forms a complex with GIT1 and various GIT-associated proteins, including betaPIX, focal adhesion kinase, liprin-alpha, and paxillin. Point mutations in the SHD of GIT1 differentially interfere with the association of GIT1 with Piccolo, betaPIX, and focal adhesion kinase, suggesting that these proteins bind to the SHD by different mechanisms. Intriguingly, GIT proteins form homo- and heteromultimers through their C-terminal G-protein-coupled receptor kinase-binding domain in a tail-to-tail fashion. This multimerization enables GIT1 to simultaneously interact with multiple SHD-binding proteins including Piccolo and betaPIX. These results suggest that, through their multimerization and interaction with Piccolo, the GIT family proteins are involved in the organization of the CAZ.     

Rapid evaluation of sorghum for aluminum tolerance

Two screening methods tested in this study were based on the observation that roots of freshly germinated seeds exhibit their relative tolerance to Al during the first 48 hours of growth. Sorghum (Sorghum bicolor L. Moench) varieties were evaluated using toxic/nontoxic soil pairs in petri dishes and toxic/nontoxic solution pairs in a flowing aqueous system. The soils had 0, 61, and 72% Al saturation and the solutions had 0, 1.85 and 3.70 M l^–1 Al from AlCl₃ and 0.25 mM l^–1 Ca from Ca(NO₃)₂. Relative root lengths in both systems correctly differentiated 13 genotypes of known Al tolerance into tolerant and intolerant groups. Twenty six other sorghums genotypes were also screened using genotypes of known Al reactions as checks. The soil with 72% Al saturation and the 1.85 M l^–1 Al solution gave the highest correlation between the two systems and both effectively arrayed sorghums of known and unknown tolerance. For routine screening the authors prefer the soil system for its simplicity, efficiency, and use of a natural growth medium.Journal paper 11637. Purdue University Agricultural Experiment Station, Lafayette, Indiana. Contribution from the Agronomy Department.     

Assessment of the Quality of Reporting of Randomised Controlled Trials in Otorhinolaryngologic Literature – Adherence to the CONSORT Statement

Background

Randomised Controlled Trials (RCTs) are the preferred study design when comparing therapeutical interventions in medicine. To improve clarity, consistency and transparency of reporting RCTs, the Consolidated Standards of Reporting Trials (CONSORT) statement was developed.

Objectives

(1) To assess the quality of reports and abstracts of RCTs in otorhinolaryngologic literature by using CONSORT checklists, (2) to compare the quality of reports and abstracts of otorhinolaryngologic RCTs between the top 5 general medical journals and top 5 otorhinolaryngologic journals, and (3) to formulate recommendations for authors and editors of otorhinolaryngologic (‘ENT’) journals.

Methods

Based on 2012 ISI Web of Knowledge impact factors, the top 5 general medical and ENT journals were selected. On 25 June 2014, using a highly sensitive Cochrane RCT filter and ENT filter, possibly relevant articles since January 1st, 2010 were retrieved and relevant RCTs were selected. We assessed how many CONSORT items were reported adequately in reports and abstracts and compared the two journal types.

Results

Otorhinolaryngologic RCTs (n = 15) published in general medical journals reported a mean of 92.1% (95% confidence interval: 89.5%–94.7%) of CONSORT items adequately, whereas RCTs (n = 18) published in ENT journals reported a mean of 71.8% (66.7%–76.8%) adequately (p < 0.001). For abstracts, means of 70.0% (63.7%–76.3%) and 32.3% (26.6–38.0%) were found respectively (p < 0.001). Large differences for specific items exist between the two journal types.

Conclusion

The quality of reporting of RCTs in otorhinolaryngologic journals is suboptimal. RCTs published in general medical journals have a higher quality of reporting than RCTs published in ENT journals. We recommend authors to report their trial according to the CONSORT Statement and advise editors to endorse the CONSORT Statement and implement the CONSORT Statement in the editorial process to ensure more adequate reporting of RCTs and their abstracts.     

An optimised version of the secretome protein enrichment with click sugars (SPECS) method leads to enhanced coverage of the secretome

The secretome, the entirety of all soluble proteins either being secreted or proteolytically released by a cell, plays a key role in inter‐cellular communication of multi‐cellular organisms. Pathological alterations contribute to diseases such as hypertension, cancer, autoimmune disorders or neurodegenerative diseases. Hence, studying disease‐related perturbations of the secretome and the secretome itself covers an important aspect of cellular physiology. We recently developed the secretome protein enrichment with click sugars (SPECS) method that enables the analysis of secretomes of in vitro cell cultures even in the presence of FCS with MS. So far, SPECS facilitated the identification of protease substrates of BACE1, SPPL3 and ADAM10. Though, the SPECS method has already enabled deep insights into secretome biology, we aimed to improve the SPECS protocol to obtain even more information from MS‐based secretome analysis and reduce the amount of input material. Here, we optimised the reaction buffer, the pH and replaced Dibenzocyclooctyne (DBCO) PEG12‐biotin with the more water‐soluble variant DBCO‐sulpho‐biotin to finally provide an optimised protocol of the recently published SPECS protocol. Overall, the number of quantified glycoproteins and their average sequence coverage was increased by 1.6‐ and 2.4‐fold, respectively. Thus, the opzimised SPECS protocol allows reducing the input material by half without losing information. These improvements make the SPECS method more sensitive and more universal applicable to cell types with limited availability.     

Epidermal ultrastructure of Seison nebaliae and Seison annulatus, and a comparison of epidermal structures within the Gnathifera

 The epidermis of both species of Seison is syncytial and has a characteristic internal layer divided into two distinct sublayers. Sublayer I is very thin (0.03 μm) and bounded to the outer cell membrane of the epidermis. Sublayer II is 0.5 μm thick and separated from sublayer I by a thin layer of cytoplasm. Intrusions of the outer cell membrane of the epidermis perforate the internal layer, before terminating within the cytoplasm. The intrusions of the cell membrane of S. annulatus are coated by an electron-dense material, the annulus, when passing through the internal layer. Bundles of filaments are present in the epidermis of S. nebaliae. A comparison of epidermal structures within the Gnathifera Ahlrichs, 1995, confirms phylogenetic relationships earlier proposed by the author. Accepted: 19 December 1996     

Ultrastructure and function of the mastax in Dicranophorus forcipatus (Rotifera: Monogononta)

Rotifers are characterized by a complex set of cuticularized jaw elements in the pharynx. The fine structure of the jaw elements has been the subject of SEM studies for some time, but only very limited information exists on the ultrastructure of the jaw elements and their function beyond taxonomic considerations. Drawing on SEM and TEM techniques, the present study presents a detailed analysis of the mastax in Dicranophorus forcipatus, a carnivorous monogonont rotifer species from freshwater habitats characterized by an extrusible, grasping jaw apparatus. Based on ultrathin serial sections, the jaw elements are reconstructed and, in total, nine paired and two unpaired muscles identified. Possibly homologous muscles in other rotifer species are discussed and functional considerations of the forcipate mastax are suggested.