Genome size rather than content might affect call properties in toads of three ploidy levels (Anura: Bufonidae: Bufo viridis subgroup)

In vertebrates, genome size has been shown to correlate with nuclear and cell sizes, and influences phenotypic features, such as brain complexity. In three different anuran families, advertisement calls of polyploids exhibit longer notes and intervals than diploids, and difference in cellular dimensions have been hypothesized to cause these modifications. We investigated this phenomenon in green toads (Bufo viridis subgroup) of three ploidy levels, in a different call type (release calls) that may evolve independently from advertisement calls, examining 1205 calls, from ten species, subspecies, and hybrid forms. Significant differences between pulse rates of six diploid and four polyploid (3n, 4n) green toad forms across a range of temperatures from 7 to 27 °C were found. Laboratory data supported differences in pulse rates of triploids vs. tetraploids, but failed to reach significance when including field recordings. This study supports the idea that genome size, irrespective of call type, phylogenetic context, and geographical background, might affect call properties in anurans and suggests a common principle governing this relationship. The nuclear‐cell size ratio, affected by genome size, seems the most plausible explanation. However, we cannot rule out hypotheses under which call‐influencing genes from an unexamined diploid ancestral species might also affect call properties in the hybrid‐origin polyploids. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 584–590.     

Effects of blood meal source on the reproduction of Culex pipiens quinquefasciatus (Diptera: Culicidae)

Culex pipiens quinquefasciatus were fed blood meals from a live chicken (LC), chicken blood in Alsever's (AC) solution, defibrinated bovine blood (DB), or bovine blood in citrate (CB) and incubated at 28° C. The effects of different blood meal sources were evaluated with respect to rates of blood feeding and reproduction (i.e., fecundity and fertility) over two gonotrophic cycles. Mosquitoes that fed on the first blood meal were subjected to a second blood meal as follows (first blood meal / second blood meal): LC/LC, LC/DB, DB/DB, CB/CB, AC/AC. Fecundity and fertility of Cx. p. quinquefasciatus were significantly (P < 0.05) greater in mosquitoes fed LC blood; however, fecundity and fertility in different treatment groups varied by gonotrophic cycle. These results contribute to our understanding of the impact of blood meal source on feeding and reproduction in Cx. p. quinquefasciatus. The potential impacts of blood meal source on virus transmission experiments are discussed.     

Novel therapies for scar reduction and regenerative healing of skin wounds

Fibrotic scars deposited during skin wound healing can cause disfiguration and loss of dermal function. Scar differentiation involves inputs from multiple cell types in a predictable and overlapping sequence of cellular events that includes inflammation, migration/proliferation and extracellular matrix deposition. Research into the molecular mechanisms underpinning these processes in embryonic and adult wounds has contributed to the development of a growing number of novel therapeutic approaches for improving scar appearance. This review discusses some of these emerging strategies for shifting the balance of healing from scarring to regeneration in the context of non-pathological wounds. Particular focus is given to potential therapies based on transforming growth factor (TGF)-beta signaling and recent unexpected findings involving targeting of gap junctional connexins. Lessons learned in promoting scarless healing of cutaneous injuries might provide a basis for regenerative healing in other scenarios, such as spinal cord rupture or myocardial infarction.     

Phylogenetic relevance of the genital sclerites of Neuropterida (Insecta: Holometabola)

Abstract Segment 9 of male Raphidioptera, comprising tergite, sternite, gonocoxites, gonostyli and gonapophyses, is a benchmark for homologies in the male and female terminalia of the three Neuropterida orders Raphidioptera, Megaloptera and Neuroptera. The segments relating to genitalia are 9, 10 and 11 in males and 7, 8 and 9 in females. Results from holomorphological and recent molecular cladistic analyses of Neuropterida agree in supporting the sister‐group relationships between: (1) the Raphidioptera and the clade Megaloptera + Neuroptera, and (2) the suborder Nevrorthiformia and all other Neuroptera. The main discrepancy between the results of these studies is the nonmonophyly of the suborder Hemerobiiformia in the molecular analysis. The monophyly of the Megaloptera (which has been repeatedly questioned) is further corroborated by a hitherto overlooked ground pattern autapomorphy: the presence of eversible sacs within the complex of the fused gonocoxites 11 in Corydalidae and Sialidae. The recently discovered paired complex of gonocoxites 10 (parameres) in Nipponeurorthus (Nevrorthidae) indicates that the curious apex of sternite 9 of Nevrorthus and Austroneurorthus is the amalgamation of the sclerites of gonocoxites 10 with sternite 9, interpreted as synapomorphic. In the molecular study, the Nevrorthidae, Sisyridae and Osmylidae branch off in consecutive splitting events, a result that is supported by the analysis of male genital sclerites reported here. Extraordinary parallel apomorphies (e.g. excessive enlargement and modification of gonocoxites 10 ending in a thread‐like ‘penisfilum’) in derived representatives of Coniopterygidae, Berothidae, Rhachiberothidae and Mantispidae corroborate the dilarid clade of the morphological analysis and leads us to hypothesize a sister‐group relationship of the Coniopterygidae with the dilarid clade. A re‐interpretation of the tignum of Chrysopidae as gonocoxites 11 means that the structure previously called the gonarcus represents the fused gonocoxites 9. In Hemerobiidae, the corresponding sclerite is consequently also homologized as fused gonocoxites 9. The enlargement of the lateral wings of the gonocoxites in both families is interpreted as a synapomorphy. Excessive enlargement of gonostyli 11 in the Polystoechotid clade and Myrmeleontiformia supports a sister‐group relationship of these two clades. The occurrence of certain serial homologues of female genitalia structures (gonocoxites and gonapophyses), such as the digitiform processus together with the flat appendices in segment 8 of certain Myrmeleontidae, or the wart‐like processus together with the flat circular sclerites in segment 7 of certain Berothidae, as well as the presence of gonocoxites 8 as pseudosternites in certain Nemopteridae and Coniopterygidae, are probably character reversals. The digitiform processus of tergite 9 (pseudogonocoxites) in Rhachiberothidae and Austroberothella (Berothidae) are either independently developed acquisitions with a function in oviposition, or are homologous sclerites, possibly of epipleurite origin.     

The reaction of 4,4'-bis-dimethylaminodiphenylcarbinol with the sulfhydryl group. A new reagent for sulfhydryl analysis

4,4′-bis-Dimethylaminodiphenylcarbinol (BDC-OH) dissociates in aqueous buffers at pH values below neutrality to form a resonance-stabilized carbonium-immonium ion (BDC⁺) which exhibits an absorbance maximum at 606 nm. In the presence of 4.0 M guanidine hydrochloride, BDC⁺ has an apparent molar absorption coefficient of 70,800 M^?1cm^?1 and an absorbance maximum of 612 nm. Sulfhydryl groups react with the cation to form S-(4,4′-bis-dimethylaminodiphenylmethyl-) derivatives with a concomitant quantitative loss of the 612-nm absorbance. This quantitative interaction has been exploited in the development of a new and convenient technique for the quantitative determination of sulfhydryl groups in proteins. Results of sulfhydryl determinations on simple thiols and five proteins are presented, along with comparison data obtained via other sulfhydryl techniques.     

Phylogeny of Myrmeleontiformia based on larval morphology (Neuropterida: Neuroptera)

The suborder Myrmeleontiformia is a derived lineage of lacewings (Insecta: Neuroptera) including the families Psychopsidae, Nemopteridae, Nymphidae, Ascalaphidae and Myrmeleontidae. In particular, Myrmeleontidae (antlions) are the most diverse neuropteran family, representing a conspicuous component of the insect fauna of xeric environments. We present the first detailed quantitative phylogenetic analysis of Myrmeleontiformia, based on 107 larval morphological and behavioural characters for 36 genera whose larvae are known (including at least one representative of all the subfamilies of the suborder). Four related families were used as outgroups to polarize character states. Phylogenetic analyses were conducted using both parsimony and Bayesian methods. The reconstructions resulting from our analyses corroborate the monophyly of Myrmeleontiformia. Within this clade, Psychopsidae are recovered as the sister family to all the remaining taxa. Nemopteridae (including both subfamilies Nemopterinae and Crocinae) are recovered as monophyletic and sister to the clade comprising Nymphidae + (Myrmeleontidae + Ascalaphidae). Nymphidae consist of two well‐supported clades corresponding to the subfamilies Nymphinae and Myiodactylinae. Our results suggest that Ascalaphidae may not be monophyletic, as they collapse into an unresolved polytomy under the Bayesian analysis. In addition, the recovered phylogenetic relationships diverge from the traditional classification scheme for ascalaphids. Myrmeleontidae are reconstructed as monophyletic, with the subfamilies Stilbopteryginae, Palparinae and Myrmeleontinae. We retrieved a strongly supported clade comprising taxa with a fossorial habit of the preimaginal instars, which represents a major antlion radiation, also including the monophyletic pit‐trap building species.     

NIST lipidomics workflow questionnaire: an assessment of community-wide methodologies and perspectives

Introduction

Efforts to harmonize lipidomic methodologies have been limited within the community. Here, we aimed to capitalize on the recent National Institute of Standards and Technology lipidomics interlaboratory comparison exercise by implementing a questionnaire that assessed current methodologies, quantitation strategies, standard operating procedures (SOPs), and quality control activities employed by the lipidomics community.

Objectives

Lipidomics is a rapidly developing field with diverse applications. At present, there are no community-vetted methods to assess measurement comparability or data quality. Thus, a major impetus of this questionnaire was to profile current efforts, highlight areas of need, and establish future objectives in an effort to harmonize lipidomics workflows.

Methods

The 54-question survey inquired about laboratory demographics, lipidomic methodologies and SOPs, analytical platforms, quantitation, reference materials, quality control procedures, and opinions regarding challenges existing within the community.

Results

A total of 125 laboratories participated in the questionnaire. A broad overview of results highlighted a wide methodological diversity within current lipidomic workflows. The impact of this diversity on lipid measurement and quantitation is currently unknown and needs to be explored further. While some laboratories do incorporate SOPs and quality control activities, these concepts have not been fully embraced by the community. The top five perceived challenges within the lipidomics community were a lack of standardization amongst methods/protocols, lack of lipid standards, software/data handling and quantification, and over-reporting/false positives.

Conclusion

The questionnaire provided an overview of current lipidomics methodologies and further promoted the need for community-accepted guidelines and protocols. The questionnaire also served as a platform to help determine and prioritize metrological issues to be investigated.

     

Long‐term monitoring of captive red drum Sciaenops ocellatus reveals that calling incidence and structure correlate with egg deposition

In the present study, quantitative data were collected to clarify the relationship between calling, call structure and eggs produced in a captive population of red drum Sciaenops ocellatus. Sciaenops ocellatus were held in four tanks equipped with long‐term acoustic loggers to record underwater sound throughout a simulated reproductive season. Maximal sound production of captive S. ocellatus occurred when the photoperiod shifted from 13·0 to 12·5 h of light, and the water temperature decreased to c. 25° C. These captive settings are similar to the amount of daylight and water temperatures observed during the autumn, which is the primary spawning period for S. ocellatus. Sciaenops ocellatus exhibited daily patterns of calling with peak sound production occurring in the evenings between 0·50 h before dark and 1·08 h after dark. Spawning occurred only on evenings in which S. ocellatus were calling, and spawning was more productive when S. ocellatus produced more calls with longer durations and more pulses. This study provides ample evidence that sound production equates to spawning in captive S. ocellatus when calls are longer than 0·8 s and contain more than seven pulses. The fact that more calling, longer calls and higher sound pressure levels are associated with spawns that are more productive indicates that acoustic metrics can provide quantitative information on spawning in the wild.     

Cardiac looping and the vertebrate left-right axis: antagonism of left-sided Vg1 activity by a right-sided ALK2-dependent BMP pathway.

The rightward looping of the primary heart tube is dependent upon upstream patterning events that establish the vertebrate left-right axis. In Xenopus, a left-sided Vg1 signaling pathway has been implicated in instructing cells to adopt a 'left-sided identity'; however, it is not known whether 'right-sided identity' is acquired by a default pathway or by antagonism of Vg1 signaling. Here, we propose that an antagonistic, BMP/ALK2/Smad-mediated signaling pathway is active on the right side of the Xenopus embryo. Truncated ALK2 receptor expression on the right side of the blastula elicits heart reversals and altered nodal expression. Consistent with these findings, constitutively active ALK2 (CA-ALK2) receptor expression on the left side of the blastula also elicits heart reversals and altered nodal expression. Coexpression of CA-ALK2 with mature Vg1 ligand results in predominantly left-sided nodal expression patterns and normal heart looping, demonstrating that the ALK2 pathway can 'rescue' left-right reversals that otherwise occur following right-sided misexpression of mature Vg1 ligand alone. Results with chimeric precursor proteins indicate that the mature domain of BMP ligands can mimic the ability of the ALK2 signaling pathway to antagonize the Vg1 pathway. Consistent with the observed antagonism between BMP and Vg1 ligands, left-sided ectopic expression of Xolloid results in heart reversals. Moreover, ectopic expression of Smad1 or Smad7 identified two downstream modulators of the BMP/ALK2 signaling pathway that also can regulate cardiac orientation. Collectively, these results define a BMP/ALK2-mediated pathway on the right side of the Xenopus embryo and, moreover, suggest that left-right patterning preceding cardiac morphogenesis involves the activation of two distinct and antagonistic, left- and right-sided TGF(beta)-related signaling pathways.     

Ozone-induced hyperresponsiveness and blockade of M2 muscarinic receptors by eosinophil major basic protein.

Control of airway smooth muscle is provided by parasympathetic nerves that release acetylcholine onto M(3) muscarinic receptors. Acetylcholine release is limited by inhibitory M(2) muscarinic receptors. In antigen-challenged guinea pigs, hyperresponsiveness is due to blockade of neuronal M(2) receptors by eosinophil major basic protein (MBP). Because exposure of guinea pigs to ozone also causes M(2) dysfunction and airway hyperresponsiveness, the role of eosinophils in ozone-induced hyperresponsiveness was tested. Animals were exposed to filtered air or to 2 parts/million ozone for 4 h. Twenty-four hours later, the muscarinic agonist pilocarpine no longer inhibited vagally induced bronchoconstriction in ozone-exposed animals, indicating M(2) dysfunction. M(2) receptor function in ozone-exposed animals was protected by depletion of eosinophils with antibody to interleukin-5 and by pretreatment with antibody to guinea pig MBP. M(2) function was acutely restored by removal of MBP with heparin. Ozone-induced hyperreactivity was also prevented by antibody to MBP and was reversed by heparin. These data show that loss of neuronal M(2) receptor function after ozone is due to release of eosinophil MBP.