Defensive behaviors of the Oriental armyworm Mythimna separata in response to different parasitoid species (Hymenoptera: Braconidae)
This study examined defensive behaviors of Mythimna separata (Lepidoptera: Noctuidae) larvae varying in body size in response to two parasitoids varying in oviposition behavior; Microplitis mediator females sting the host with the ovipositor after climbing onto it while Meteorus pulchricornis females make the sting by standing at a close distance from the host. Mythimna separata larvae exhibited evasive (escaping and dropping) and aggressive (thrashing) behaviors to defend themselves against parasitoids M. mediator and M. pulchricornis. Escaping and dropping did not change in probability with host body size or parasitoid species. Thrashing did not vary in frequency with host body size, yet performed more frequently in response to M. mediator than to M. pulchricornis. Parasitoid handling time and stinging likelihood varied depending not only on host body size but also on parasitoid species. Parasitoid handling time increased with host thrashing frequency, similar in slope for both parasitoids yet on a higher intercept for M. mediator than for M. pulchricornis. Handling time decreased with host size for M. pulchricornis but not for M. mediator. The likelihood of realizing an ovipositor sting decreased with thrashing frequency of both small and large hosts for M. pulchricornis, while this was true only for large hosts for M. mediator. Our results suggest that the thrashing behavior of M. separata larvae has a defensive effect on parasitism, depending on host body size and parasitoid species with different oviposition behaviors.
Zhou et al. (2017) Defensive behaviors of the Oriental armyworm Mythimna separata in response to different parasitoid species (Hymenoptera: Braconidae). PeerJ 5:e3690 https://doi.org/10.7717/peerj.3690
A Miocene breeding ground of an extinct baleen whale (Cetacea: Mysticeti)
Locating breeding sites is definitely a key to understanding the ecological requirements and maintaining the sustainability of populations/species. Here I re-examined published specimens of an extinct baleen whale, Parietobalaena yamaokai, from the lower part of Itahashi Formation (16.1–15.6 Ma, Middle Miocene) in Shobara, Hiroshima, Japan. A critical and previously unnoticed feature, the open suture between the supraoccipital and exoccipital, in one specimen indicates the preservation of a very young individual–under six months old and even close to a new-born calf. Given the occurrence of a new-born whale and relatively abundant assemblage of Parietobalaena yamaokai, I propose a previously hidden and unknown breeding ground for the extinct baleen whale, P. yamaokai, in the Middle Miocene of Shobara (16.1–15.6 Ma), Hiroshima. Discovery of paleo-breeding sites of extinct populations/species should further help us to understand biological extinctions from a long-term perspective as conservation paleobiology aims to offer new insights into policy making for conserving endangered populations/species.
Tsai (2017) A Miocene breeding ground of an extinct baleen whale (Cetacea: Mysticeti). PeerJ 5:e3711 https://doi.org/10.7717/peerj.3711
Acetylation of N-terminus and two internal amino acids is dispensable for degradation of a protein that aberrantly engages the endoplasmic reticulum translocon
Conserved homologues of the Hrd1 ubiquitin ligase target for degradation proteins that persistently or aberrantly engage the endoplasmic reticulum translocon, including mammalian apolipoprotein B (apoB; the major protein component of low-density lipoproteins) and the artificial yeast protein Deg1-Sec62. A complete understanding of the molecular mechanism by which translocon-associated proteins are recognized and degraded may inform the development of therapeutic strategies for cholesterol-related pathologies. Both apoB and Deg1-Sec62 are extensively post-translationally modified. Mass spectrometry of a variant of Deg1-Sec62 revealed that the protein is acetylated at the N-terminal methionine and two internal lysine residues. N-terminal and internal acetylation regulates the degradation of a variety of unstable proteins. However, preventing N-terminal and internal acetylation had no detectable consequence for Hrd1-mediated proteolysis of Deg1-Sec62. Our data highlight the importance of empirically validating the role of post-translational modifications and sequence motifs on protein degradation, even when such elements have previously been demonstrated sufficient to destine other proteins for destruction.
Engle et al. (2017) Acetylation of N-terminus and two internal amino acids is dispensable for degradation of a protein that aberrantly engages the endoplasmic reticulum translocon. PeerJ 5:e3728 https://doi.org/10.7717/peerj.3728
Histological characterization of denticulate palatal plates in an Early Permian dissorophoid
Denticles are small, tooth-like protrusions that are commonly found on the palate of early tetrapods. Despite their widespread taxonomic occurrence and similar external morphology to marginal teeth, it has not been rigorously tested whether denticles are structurally homologous to true teeth with features such as a pulp cavity, dentine, and enamel, or if they are bony, tooth-like protrusions. Additionally, the denticles are known to occur not only on the palatal bones but also on a mosaic of small palatal plates that is thought to have covered the interpterygoid vacuities of temnospondyls through implantation in a soft tissue covering; however, these plates have never been examined beyond a simple description of their position and external morphology. Accordingly, we performed a histological analysis of these denticulate palatal plates in a dissorophoid temnospondyl in order to characterize their microanatomy and histology. The dentition on these palatal plates has been found to be homologous with true teeth on the basis of both external morphology and histological data through the identification of features such as enamel and a pulp cavity surrounded by dentine. In addition, patterns of tooth replacement and ankylosis support the hypothesis of structural homology between these tiny teeth on the palatal plates and the much larger marginal dentition. We also provide the first histological characterization of the palatal plates, including documentation of abundant Sharpey’s fibres that provide a direct line of evidence to support the hypothesis of soft tissue implantation. Finally, we conducted a survey of the literature to determine the taxonomic distribution of these plates within Temnospondyli, providing a broader context for the presence of palatal plates and illustrating the importance of maintaining consistency in nomenclature.
Gee et al. (2017) Histological characterization of denticulate palatal plates in an Early Permian dissorophoid. PeerJ 5:e3727 https://doi.org/10.7717/peerj.3727
Effects of linear and daily undulating periodized resistance training programs on measures of muscle hypertrophy: a systematic review and meta-analysis
Background Periodization is an important component of resistance training programs. It is meant to improve adherence to the training regimen, allow for constant progression, help in avoiding plateaus, and reduce occurrence and severity of injuries. Previous findings regarding the effects of different periodization models on measures of muscle hypertrophy are equivocal. To provide a more in-depth look at the topic, we undertook a systematic review of the literature and a meta-analysis of intervention trials comparing the effects of linear periodization (LP) and daily undulating periodization (DUP) resistance training programs on muscle hypertrophy. Materials and Methods A comprehensive literature search was conducted through PubMed/MEDLINE, Scopus, Web of Science, SPORTDiscus, Networked Digital Library of Theses and Dissertations (NDLTD) and Open Access Theses and Dissertations (OATD). Results The pooled standardized mean difference (Cohen’s d) from 13 eligible studies for the difference between the periodization models on muscle hypertrophy was −0.02 (95% confidence interval [−0.25, 0.21], p = 0.848). Conclusions The meta-analysis comparing LP and DUP indicated that the effects of the two periodization models on muscle hypertrophy are likely to be similar. However, more research is needed in this area, particularly among trained individuals and clinical populations. Future studies may benefit from using instruments that are more sensitive for detecting changes in muscle mass, such as ultrasound or magnetic resonance imaging.
Grgic et al. (2017) Effects of linear and daily undulating periodized resistance training programs on measures of muscle hypertrophy: a systematic review and meta-analysis. PeerJ 5:e3695 https://doi.org/10.7717/peerj.3695
The complete mitochondrial genome of the grooved carpet shell, Ruditapes decussatus (Bivalvia, Veneridae)
Despite the large number of animal complete mitochondrial genomes currently available in public databases, knowledge about mitochondrial genomics in invertebrates is uneven. This paper reports, for the first time, the complete mitochondrial genome of the grooved carpet shell, Ruditapes decussatus, also known as the European clam. Ruditapes decussatus is morphologically and ecologically similar to the Manila clam Ruditapes philippinarum, which has been recently introduced for aquaculture in the very same habitats of Ruditapes decussatus, and that is replacing the native species. Currently the production of the European clam is almost insignificant, nonetheless it is considered a high value product, and therefore it is an economically important species, especially in Portugal, Spain and Italy. In this work we: (i) assembled Ruditapes decussatus mitochondrial genome from RNA-Seq data, and validated it by Sanger sequencing; (ii) analyzed and characterized the Ruditapes decussatus mitochondrial genome, comparing its features with those of other venerid bivalves; (iii) assessed mitochondrial sequence polymorphism (SP) and copy number variation (CNV) of tandem repeats across 26 samples. Despite using high-throughput approaches we did not find evidence for the presence of two sex-linked mitochondrial genomes, typical of the doubly uniparental inheritance of mitochondria, a phenomenon known in ∼100 bivalve species. According to our analyses, Ruditapes decussatus is more genetically similar to species of the Genus Paphia than to the congeneric Ruditapes philippinarum, a finding that bolsters the already-proposed need of a taxonomic revision. We also found a quite low genetic variability across the examined samples, with few SPs and little variability of the sequences flanking the control region (Largest Unassigned Regions (LURs). Strikingly, although we found low nucleotide variability along the entire mitochondrial genome, we observed high levels of length polymorphism in the LUR due to CNV of tandem repeats, and even a LUR length heteroplasmy in two samples. It is not clear if the lack of genetic variability in the mitochondrial genome of Ruditapes decussatus is a cause or an effect of the ongoing replacement of Ruditapes decussatus with the invasive Ruditapes philippinarum, and more analyses, especially on nuclear sequences, are required to assess this point.
Ghiselli et al. (2017) The complete mitochondrial genome of the grooved carpet shell, Ruditapes decussatus (Bivalvia, Veneridae). PeerJ 5:e3692 https://doi.org/10.7717/peerj.3692
Structural dynamics in the host-parasitoid system of the pine needle gall midge (Thecodiplosis japonensis) during invasion
The structural dynamics of host–parasitoid populations play a key role in the mechanism of natural community development with invasive species. Species invading new habitats experience coevolution with their newly acquired natural enemies, and their population dynamics are driven by a complex interaction between biological and environmental factors. We examined the biological and environmental factors which potentially influence a community of parasitoids throughout the 25-year invasion history of the pine needle gall midge (PNGM), Thecodiplosis japonensis, an important pest of pines in eastern Asia. We found that differences in establishment sequence and competitive ability among the parasitoids attacking this species determined the parasitoid community’s structure and dynamics. In particular, the timing for the initial establishment of the host–parasitoid association, incomplete superiority in competition among parasitoids, and indirect competition by a combination of the parasitoids were important factors for determining community’s structure and dynamics. Finally, the history of change in the community composition could be explained by the phenology differences in its member species, mediated by environmental factors.
Choi et al. (2017) Structural dynamics in the host-parasitoid system of the pine needle gall midge (Thecodiplosis japonensis) during invasion. PeerJ 5:e3610 https://doi.org/10.7717/peerj.3610
A demographic history of a population of howler monkeys (Alouatta palliata) living in a fragmented landscape in Mexico
Long-term field studies are critical for our understanding of animal life history and the processes driving changes in demography. Here, we present long-term demographic data for the northernmost population of mantled howler monkeys (Alouatta palliata) residing in a highly anthropogenically fragmented landscape in Los Tuxtlas, Mexico. We carried out 454 monthly group visits to 10 groups of mantled howler monkeys between 2000 and 2011. The population remained relatively stable over the 11-year study period, with an overall increase in the total number of individuals. Birth rates and inter-birth intervals were comparable to those of howler monkeys at non-fragmented sites, suggesting that living in a fragmented landscape did not affect the reproductive output of our study population. Moreover, despite the landscape, dispersal events were commonplace, including many secondary dispersals (individuals emigrating from groups that they had previously immigrated into). Finally, we found a marked effect of seasonality on the dynamics of our study population. In particular, the period of lowest temperatures and resource scarcity between November and March was associated with higher mortality and reproductive inhibition, while the period of resource abundance between April and May was associated with the majority of conceptions and weaning of offspring. This, in turn, could be influencing dispersal patterns in our study area, as male howler monkeys seem to time some of their immigrations into new groups to coincide with the start of the period of higher fertility, while females preferentially joined new groups several months before the onset of this period. These data have important implications for the conservation and management of howler monkeys in fragmented landscapes, as well as for our understanding of the effect of seasonality over howler monkey dispersal, reproduction and survival.
Cristóbal Azkarate et al. (2017) A demographic history of a population of howler monkeys (Alouatta palliata) living in a fragmented landscape in Mexico. PeerJ 5:e3547 https://doi.org/10.7717/peerj.3547
The effects of allogenic stem cells in a murine model of hind limb diabetic ischemic tissue
Background Diabetes is one of the major risk factors for peripheral arterial disease. In patients in whom surgery cannot be performed, cell therapy may be an alternative treatment. Since time is crucial for these patients, we propose the use of allogenic mesenchymal cells. Methods We obtained mesenchymal cells derived from the fat tissue of a healthy Sprague-Dawley rat. Previous diabetic induction with streptozotocin in 40 male Sprague-Dawley rats, ligation plus left iliac and femoral artery sections were performed as a previously described model of ischemia. After 10 days of follow-up, macroscopic and histo-pathological analysis was performed to evaluate angiogenic and inflammatory parameters in the repair of the injured limb. All samples were evaluated by the same blind researcher. Statistical analysis was performed using the SPSS v.11.5 program (P < 0.05). Results Seventy percent of the rats treated with streptozotocin met the criteria for diabetes. Macroscopically, cell-treated rats presented better general and lower ischemic clinical status, and histologically, a better trend towards angiogenesis, greater infiltration of type 2 macrophages and a shortening of the inflammatory process. However, only the inflammatory variables were statistically significant. No immunological reaction was observed with the use of allogeneic cells. Discussion The application of allogeneic ASCs in a hind limb ischemic model in diabetic animals shows no rejection reactions and a reduction in inflammatory parameters in favor of better repair of damaged tissue. These results are consistent with other lines of research in allogeneic cell therapy. This approach might be a safe, effective treatment option that makes it feasible to avoid the time involved in the process of isolation, expansion and production of the use of autologous cells.
Álvarez García et al. (2017) The effects of allogenic stem cells in a murine model of hind limb diabetic ischemic tissue. PeerJ 5:e3664 https://doi.org/10.7717/peerj.3664
Population structure of Bathymodiolus manusensis, a deep-sea hydrothermal vent-dependent mussel from Manus Basin, Papua New Guinea
Deep-sea hydrothermal vents in the western Pacific are increasingly being assessed for their potential mineral wealth. To anticipate the potential impacts on biodiversity and connectivity among populations at these vents, environmental baselines need to be established. Bathymodiolus manusensis is a deep-sea mussel found in close association with hydrothermal vents in Manus Basin, Papua New Guinea. Using multiple genetic markers (cytochrome C-oxidase subunit-1 sequencing and eight microsatellite markers), we examined population structure at two sites in Manus Basin separated by 40 km and near a potential mining prospect, where the species has not been observed. No population structure was detected in mussels sampled from these two sites. We also compared a subset of samples with B. manusensis from previous studies to infer broader population trends. The genetic diversity observed can be used as a baseline against which changes in genetic diversity within the population may be assessed following the proposed mining event.
Thaler et al. (2017) Population structure of Bathymodiolus manusensis, a deep-sea hydrothermal vent-dependent mussel from Manus Basin, Papua New Guinea. PeerJ 5:e3655 https://doi.org/10.7717/peerj.3655