Galls induced by Calophya latiforceps (Hemiptera: Calophyidae) reduce leaf performance and growth of Brazilian peppertree

Schinus terebinthifolia Raddi (Anacardiaceae) (Brazilian peppertree) is one of the most serious terrestrial invasive plants in Florida. The leaf galling psyllid, Calophya latiforceps Burckhardt (Hemiptera: Calophyidae), was discovered feeding on the Brazilian peppertree in Bahia, Brazil, in 2010, and is being evaluated for release as a biological control agent. In order to understand how this candidate biological control agent affects the growth of S. terebinthifolia, we measured the effect of the psyllid on photosynthesis, leaf chlorophyll content and plant growth. Infested plants had lower photosynthesis compared to uninfested plants 30 and 45 days after gall initiation, and chlorophyll content was lower over a 70-d period. Plant height was reduced 31% and biomass 11% after three months of infestation. Results of these studies suggest that C. latiforceps will negatively affect the growth of the Brazilian peppertree if released in Florida.     

Addicted? Reduced host resistance in populations with defensive symbionts

Heritable symbionts that protect their hosts from pathogens have been described in a wide range of insect species. By reducing the incidence or severity of infection, these symbionts have the potential to reduce the strength of selection on genes in the insect genome that increase resistance. Therefore, the presence of such symbionts may slow down the evolution of resistance. Here we investigated this idea by exposing Drosophila melanogaster populations to infection with the pathogenic Drosophila C virus (DCV) in the presence or absence of Wolbachia, a heritable symbiont of arthropods that confers protection against viruses. After nine generations of selection, we found that resistance to DCV had increased in all populations. However, in the presence of Wolbachia the resistant allele of pastrel—a gene that has a major effect on resistance to DCV—was at a lower frequency than in the symbiont-free populations. This finding suggests that defensive symbionts have the potential to hamper the evolution of insect resistance genes, potentially leading to a state of evolutionary addiction where the genetically susceptible insect host mostly relies on its symbiont to fight pathogens.     

Making sense of ‘lower’ and ‘upper’ stem‐group Euarthropoda,with comments on the strict use of the name Arthropoda von Siebold, 1848

The ever‐increasing number of studies that address the origin and evolution of Euarthropoda – whose extant representatives include chelicerates, myriapods, crustaceans and hexapods – are gradually reaching a consensus with regard to the overall phylogenetic relationships of some of the earliest representatives of this phylum. The stem‐lineage of Euarthropoda includes numerous forms that reflect the major morphological transition from a lobopodian‐type to a completely arthrodized body organization. Several methods of classification that aim to reflect such a complex evolutionary history have been proposed as a consequence of this taxonomic diversity. Unfortunately, this has also led to a saturation of nomenclatural schemes, often in conflict with each other, some of which are incompatible with cladistic‐based methodologies. Here, I review the convoluted terminology associated with the classification of stem‐group Euarthropoda, and propose a synapomorphy‐based distinction that allows ‘lower stem‐Euarthropoda’ (e.g. lobopodians, radiodontans) to be separated from ‘upper stem‐Euarthropoda’ (e.g. fuxianhuiids, Cambrian bivalved forms) in terms of the structural organization of the head region and other aspects of overall body architecture. The step‐wise acquisition of morphological features associated with the origins of the crown‐group indicate that the node defining upper stem‐Euarthropoda is phylogenetically stable, and supported by numerous synapomorphic characters; these include the presence of a deutocerebral first appendage pair, multisegmented head region with one or more pairs of post‐ocular differentiated limbs, complete body arthrodization, posterior‐facing mouth associated with the hypostome/labrum complex, and post‐oral biramous arthropodized appendages. The name ‘Deuteropoda’ nov. is proposed for the scion (monophyletic group including the crown‐group and an extension of the stem‐group) that comprises upper stem‐Euarthropoda and Euarthropoda. A brief account of common terminological inaccuracies in recent palaeontological studies evinces the utility of Deuteropoda nov. as a reference point for discussing aspects of early euarthropod phylogeny.     

The impact of <Emphasis Type="Italic">MTHFR</Emphasis> 677C → T risk knowledge on changes in folate intake: findings from the Food4Me study

Background

It is hypothesised that individuals with knowledge of their genetic risk are more likely to make health-promoting dietary and lifestyle changes. The present study aims to test this hypothesis using data from the Food4Me study. This was a 6-month Internet-based randomised controlled trial conducted across seven centres in Europe where individuals received either general healthy eating advice or varying levels of personalised nutrition advice. Participants who received genotype-based personalised advice were informed whether they had the risk (CT/TT) (n?=?178) or non-risk (CC) (n?=?141) alleles of the methylenetetrahydrofolate reductase (MTHFR) gene in relation to cardiovascular health and the importance of a sufficient intake of folate. General linear model analysis was used to assess changes in folate intake between the MTHFR risk, MTHFR non-risk and control groups from baseline to month 6 of the intervention.

Results

There were no differences between the groups for age, gender or BMI. However, there was a significant difference in country distribution between the groups (p?=?0.010). Baseline folate intakes were 412?±?172, 391?±?190 and 410?±?186 μg per 10 MJ for the risk, non-risk and control groups, respectively. There were no significant differences between the three groups in terms of changes in folate intakes from baseline to month 6. Similarly, there were no changes in reported intake of food groups high in folate.

Conclusions

These results suggest that knowledge of MTHFR 677C?→?T genotype did not improve folate intake in participants with the risk variant compared with those with the non-risk variant.

Trial registration

ClinicalTrials.gov NCT01530139

     

The characterization of macroH2A beyond vertebrates supports an ancestral origin and conserved role for histone variants in chromatin

Histone variants play a critical role in chromatin structure and epigenetic regulation. These “deviant” proteins have been historically considered as the evolutionary descendants of ancestral canonical histones, helping specialize the nucleosome structure during eukaryotic evolution. Such view is now challenged by 2 major observations: first, canonical histones present extremely unique features not shared with any other genes; second, histone variants are widespread across many eukaryotic groups. The present work further supports the ancestral nature of histone variants by providing the first in vivo characterization of a functional macroH2A histone (a variant long defined as a specific refinement of vertebrate chromatin) in a non-vertebrate organism (the mussel Mytilus) revealing its recruitment into heterochromatic fractions of actively proliferating tissues. Combined with in silico analyses of genomic data, these results provide evidence for the widespread presence of macroH2A in metazoan animals, as well as in the holozoan Capsaspora, supporting an evolutionary origin for this histone variant lineage before the radiation of Filozoans (including Filasterea, Choanoflagellata and Metazoa). Overall, the results presented in this work help configure a new evolutionary scenario in which histone variants, rather than modern “deviants” of canonical histones, would constitute ancient components of eukaryotic chromatin.     

Hepatic myelolipoma in two Goeldi's monkeys from South America held captive

Two cases of hepatic myelolipoma in Goeldi's monkeys from South America are described. One was a female evaluated due progressive abdominal distension. Ultrasound and computed tomography detected hepatic mass. Partial hepatectomy was performed, but the monkey died after surgery. Case 2 was a male that died suddenly, showing non‐specific clinical signs.