Multidimensional epistasis and fitness landscapes in enzyme evolution

The conventional analysis of enzyme evolution is to regard one single salient feature as a measure of fitness, expressed in a milieu exposing the possible selective advantage at a given time and location. Given that a single protein may serve more than one function, fitness should be assessed in several dimensions. In the present study we have explored individual mutational steps leading to a triple-point-mutated human GST (glutathione transferase) A2-2 displaying enhanced activity with azathioprine. A total of eight alternative substrates were used to monitor the diverse evolutionary trajectories. The epistatic effects of the mutations on catalytic activity were variable in sign and magnitude and depended on the substrate used, showing that epistasis is a multidimensional quality. Evidently, the multidimensional fitness landscape can lead to alternative trajectories resulting in enzymes optimized for features other than the selectable markers relevant at the origin of the evolutionary process. In this manner the evolutionary response is robust and can adapt to changing environmental conditions.     

Neuroprotective and anticonvulsant effects of organic and conventional purple grape juices on seizures in Wistar rats induced by pentylenetetrazole

Epilepsy is the most common neurological disorder worldwide. Studies have shown that recurrent seizures may increase the concentration of reactive oxygen species, which can lead to oxidative stress and neuronal damage. These seizures result in substantial deleterious effects on an individual's health. Organic and conventional grape juices are rich in polyphenols, compounds with important antioxidant activity. However, these juices could have differences in their polyphenol content. The aim of this study was to investigate the neuroprotective and anticonvulsant effects of organic and conventional grape juice treatments in Wistar rats against pentylenetetrazole (a convulsant drug)-induced damage. In addition, we evaluated potential behavioral changes in rats treated with the juices and the polyphenolic profile of those samples. Animals (n=16 in each group) received treatment with saline, organic or conventional grape juice for 17 days. On the eighteenth day, behavioral changes were evaluated by an open field test. Afterwards, half of the rats from each group received pentylenetetrazole and were observed for 30 min to evaluate possible seizure characteristics. The animals were subsequently killed by decapitation and their hippocampus, cerebellum and cerebral cortex tissues were isolated. The results of this study showed that neither organic nor conventional grape juice altered the behavior parameters, and no statistical differences were observed in the seizure characteristics of the groups. Nevertheless, both juice types were able to protect from lipid and protein oxidative damage, decrease nitric oxide content and increase enzymatic (superoxide dismutase and catalase) and non-enzymatic (sulfhydryl protein) antioxidant defenses in brain tissues following pentylenetetrazole-induced seizures. In general, organic juice showed superior results in each test, probably due to its higher polyphenol content relative to conventional juice. These results indicate that grape juices can provide further insight into natural neuroprotective compounds and may lead to the development of new therapeutic strategies for epileptic patients.     

One clutch or two clutches? Fitness correlates of coexisting alternative female life-histories in the European earwig

Whether to reproduce once or multiple times (semelparity vs. iteroparity) is a major life-history decision that organisms have to take. Mode of parity is usually considered a species characteristic. However, recent models suggested that population properties or condition-dependent fitness payoffs could help to maintain both life-history tactics within populations. In arthropods, semelparity was also hypothesised to be a critical pre-adaptation for the evolution of maternal care, semelparous females being predicted to provide more care due to the absence of costs on future reproduction. The aim of this study was to characterize potential fitness payoffs and levels of maternal care in semel- and itero-parous females of the European earwig Forficula auricularia. Based on 15 traits measured in 494 females and their nymphs, our results revealed that iteroparous females laid their first clutch earlier, had more eggs in their first clutch, gained more weight during the 2 weeks following hatching of the first clutch, but produced eggs that developed more slowly than semelparous females. Among iteroparous females, the sizes of first and second clutches were significantly and positively correlated, indicating no investment trade-off between reproductive events. Iteroparous females also provided more food than semelparous ones, a result contrasting with predictions that iteroparity is incompatible with the evolution of maternal care. Finally, a controlled breeding experiment reported full mating compatibility among offspring from females of the two modes of parity, confirming that both types of females belong to one single species. Overall, these results indicate that alternative modes of parity represent coexisting life-history tactics that are likely to be condition-dependent and associated with offspring development and specific levels of maternal care in earwigs.     

Flexibility and persistence of chimpanzee (Pan troglodytes) foraging behavior in a captive environment

As a result of environmental variability, animals may be confronted with uncertainty surrounding the presence of, or accessibility to, food resources at a given location or time. While individuals can rely on personal experience to manage this variability, the behavior of members of an individual's social group can also provide information regarding the availability or location of a food resource. The purpose of the present study was to measure how captive chimpanzees individually and collectively adjust their foraging strategies at an artificial termite mound, as the availability of resources provided by the mound varied over a number of weeks. As predicted, fishing activity at the mound was related to resource availability. However, chimpanzees continued to fish at unbaited locations on the days and weeks after a location had last contained food. Consistent with previous studies, our findings show that chimpanzees do not completely abandon previously learned habits despite learning individually and/or socially that the habit is no longer effective.     

Equine fetal sex determination using circulating cell-free fetal DNA (ccffDNA)

In this study, polymerase chain reaction (PCR) reamplification of the first PCR product (2nd-PCR) and a qPCR assay were used to detect the sex determining region Y (SRY) gene from circulating cell-free fetal DNA (ccffDNA) in blood plasma of pregnant mares to determine fetal sex. The ccffDNA was isolated from plasma of 20 Thoroughbred mares (5-13 y old) in the final 3 mo of pregnancy (fetal sex was verified after foaling). For controls, plasma from two non-pregnant mares and two virgin mares were used, in addition to the non-template control. The 182 bp nucleotide sequence corresponding to the SRY-PCR product was confirmed by DNA sequencing. Based on SRY/PCR, 8 of 11 male and 9 of 9 female fetuses were correctly identified, resulting in a sensitivity of 72.7% (for male fetuses) and an overall accuracy of 85%. Furthermore, using SRY/2nd-PCR and qPCR techniques, sensitivity and accuracy were 90.9 and 95%, respectively. In conclusion, this study is apparently the first report of fetal sex determination in mares using ccffDNA.     

A Molecular Enrichment Strategy Based on <Emphasis Type="Italic">cpn</Emphasis>60 for Detection of Epsilon-Proteobacteria in the Dog Fecal Microbiome

Members of the rare microbiome can be important components of complex microbial communities. For example, pet dog ownership is a known risk factor for human campylobacteriosis, and Campylobacter is commonly detected in dog feces by targeted assays. However, these organisms have not been detected by metagenomic methods. The goal of this study was to characterize fecal microbiota from healthy and diarrheic pet dogs using two different levels of molecular detection. PCR amplification and pyrosequencing of the universal cpn60 gene target was used to obtain microbial profiles from each dog. To investigate the relatively rare epsilon-proteobacteria component of the microbiome, a molecular enrichment was carried out using a PCR that first amplified the cpn10–cpn60 region from epsilon-proteobacteria, followed by universal cpn60 target amplification and pyrosequencing. From the non-enriched survey, the major finding was a significantly higher proportion of Bacteroidetes, notably Bacteroides vulgatus, in healthy dogs compared to diarrheic dogs. Epsilon-proteobacteria from the genera Helicobacter and Campylobacter were also detected at a low level in the non-enriched profiles of some dogs. Molecular enrichment increased the proportion of epsilon-proteobacteria sequences detected from each dog, as well as identified novel, presumably rare sequences not seen in the non-enriched profiles. Enriched profiles contained known species of Arcobacter, Campylobacter, Flexispira, and Helicobacter and identified two possibly novel species. These findings add to our understanding of the canine fecal microbiome in general, the epsilon-proteobacteria component specifically, and present a novel modification to traditional metagenomic approaches for study of the rare microbiome.     

Three new species,four new records and an updated checklist of Habenaria (Orchidaceae) from Rio Grande do Sul,Brazil

Three new species of Habenaria (Orchidaceae) section Nudae from Rio Grande do Sul, southern Brazil, are described and illustrated: Habenaria australis, H. kleinii and H. sobraliana. These are the first records of H. sect. Nudae for the state. Based on the examination of living and dried specimens, a total of 33 species and 400 collections of Habenaria were recorded for Rio Grande do Sul. Based on this survey, an updated checklist of the genus Habenaria for Rio Grande do Sul has been compiled. Four species are known only from this state, while seven other species are restricted to southern Brazil, Argentina and Uruguay. Habenaria hieronymi, previously known only from Argentina, is recorded for the first time from Brazil, and H. brachyphyton, H. ekmaniana and H. melanopoda are new records for Rio Grande do Sul.     

Mitochondrial gene order change in Schistosoma (Platyhelminthes: Digenea: Schistosomatidae)

In the flatworm genus Schistosoma, species of which include parasites of biomedical and veterinary importance, mitochondrial gene order is radically different in some species. A PCR-based survey of 19 schistosomatid spp. established which of 14 Schistosoma spp. have the ancestral (plesiomorphic) or derived gene order condition. A phylogeny for Schistosoma was estimated and used to infer the origin of the gene order change which is present in all members of a clade containing Schistosoma incognitum and members of the traditionally recognised Schistosoma indicum, Schistosoma mansoni and Schistosoma haematobium spp. groups. Schistosoma turkestanicum, with the plesiomorphic gene order state, is sister to this clade. Common interval analysis suggests change in gene order, from ancestral to derived, consisted of two sequential transposition events: (a) nad1_nad3 to nad3_nad1 and (b) [atp6,nad2]_[nad3,nad1,cox1,rrnL,rrnS,cox2,nad6] to [nad3,nad1,cox1,rrnL,rrnS,cox2,nad6]_[atp6,nad2], where gene order of fragments within square brackets remain unchanged. Gene order change is rare in parasitic flatworms and is a robust synapomorphy for schistosome spp. that exhibit it. The schistosomatid phylogeny casts some doubt on the origin of Schistosoma (Asian or African), highlights the propensity for species to host switch amongst mammalian (definitive) hosts, and indicates the likely importance of snail (intermediate) hosts in determining and defining patterns of schistosome radiation and continental invasion. Mitogenomic sampling of Schistosoma dattai and Schistosoma harinasutai to determine gene order, and within key species, especially S. turkestanicum and S. incognitum, to determine ancestral ranges, may help discover the geographic origins of gene order change in the genus. Samples of S. incognitum from India and Thailand suggest this taxon may include cryptic species.