Calcification and growth rate recovery of the reef-building Pocillopora species in the northeast tropical Pacific following an ENSO disturbance
Pocilloporids are one of the major reef-building corals in the eastern tropical Pacific (ETP) and also the most affected by thermal stress events, mainly those associated with El Niño/Southern Oscillation (ENSO) periods. To date, coral growth parameters have been poorly reported in Pocillopora species in the northeastern region of the tropical Pacific. Monthly and annual growth rates of the three most abundant morphospecies (P. cf. verrucosa, P. cf. capitata, and P. cf. damicornis) were evaluated during two annual periods at a site on the Pacific coast of Mexico. The first annual period, 2010–2011 was considered a strong ENSO/La Niña period with cool sea surface temperatures, then followed by a non-ENSO period in 2012–2013. The linear extension rate, skeletal density, and calcification rate averaged (±SD) were 2.31 ± 0.11 cm yr−1, 1.65 ± 0.18 g cm−3, 5.03 ± 0.84 g cm−2 yr-1 respectively, during the strong ENSO event. In contrast, the respective non-ENSO values were 3.50 ± 0.64 cm yr−1, 1.70 ± 0.18 g cm−3, and 6.02 ± 1.36 g cm−2 yr−1. This corresponds to 52% and 20% faster linear extension and calcification rates, respectively, during non-ENSO period. The evidence suggests that Pocillopora branching species responded positively with faster growth rates following thermal anomalies, which allow them to maintain coral communities in the region.
Tortolero-Langarica et al. (2017) Calcification and growth rate recovery of the reef-building Pocillopora species in the northeast tropical Pacific following an ENSO disturbance. PeerJ 5:e3191 https://doi.org/10.7717/peerj.3191
Effects of chronic exposure to clothianidin on the earthworm Lumbricus terrestris
Although neonicotinoids are targeted at insects, their predominant use as a seed dressing and their long persistence in soils mean that non-target soil organisms such as earthworms are likely to be chronically exposed to them. Chronic exposure may pose risks that are not evaluated in most toxicity tests. We experimentally tested the effect of field-realistic concentrations of a commonly used neonicotinoid, clothianidin, on mortality, weight gain, and food consumption to assess the impacts of chronic exposure over four months on fitness of L. terrestris individuals. We undertook three separate experiments, each with different exposure routes: treated soil only (experiment A), treated food and soil combined (experiment B) and treated food only (experiment C). Mortality was negatively affected by exposure from treated soil only with greatest mortality observed in the groups exposed to the two highest concentrations (20 ppb and 100 ppb), but no clear effect on mortality was found in the other two experiments. When clothianidin was present in the food, an anti-feedant effect was present in months one and two which subsequently disappeared; if this occurs in the field, it could result in reduced rates of decomposition of treated crop foliage. We found no significant effects of any treatment on worm body mass. We cannot rule out stronger adverse effects if worms come into close proximity to treated seeds, or if other aspects of fitness were examined. Overall, our data suggest that field-realistic exposure to clothianidin has a significant but temporary effect on food consumption and can have weak but significant impacts on mortality of L. terrestris.
Basley et al. (2017) Effects of chronic exposure to clothianidin on the earthworm Lumbricus terrestris. PeerJ 5:e3177 https://doi.org/10.7717/peerj.3177
Mechanism of endothelial nitric oxide synthase phosphorylation and activation by tentacle extract from the jellyfish Cyanea capillata
Our previous study demonstrated that tentacle extract (TE) from the jellyfish Cyanea capillata (C. capillata) could cause a weak relaxation response mediated by nitric oxide (NO) using isolated aorta rings. However, the intracellular mechanisms of TE-induced vasodilation remain unclear. Thus, this study was conducted to examine the role of TE on Akt/eNOS/NO and Ca2+ signaling pathways in human umbilical vein endothelial cells (HUVECs). Our results showed that TE induced dose- and time-dependent increases of eNOS activity and NO production. And TE also induced Akt and eNOS phosphorylation in HUVECs. However, treatment with specific PI3-kinase inhibitor (Wortmannin) significantly inhibited the increases in NO production and Akt/eNOS phosphorylation. In addition, TE also stimulated an increase in the intracellular Ca2+ concentration ([Ca2+]i), which was significantly attenuated by either IP3 receptor blocker (Heparin) or PKC inhibitor (PKC 412). In contrast, extracellular Ca2+-free, L-type calcium channel blocker (Nifedipine), or PKA inhibitor (H89) had no influence on the [Ca2+]i elevation. Since calcium ions also play a critical role in stimulating eNOS activity, we next explored the role of Ca2+ in TE-induced Akt/eNOS activation. In consistent with the attenuation of [Ca2+]i elevation, we found that Akt/eNOS phosphorylation was also dramatically decreased by Heparin or PKC 412, but not affected by Nifedipine or H89. However, the phosphorylation level could also be decreased by the removal of extracellular calcium. Taken together, our findings indicated that TE-induced eNOS phosphorylation and activation were mainly through PI3K/Akt-dependent, PKC/IP3R-sensitive and Ca2+-dependent pathways.
Wang et al. (2017) Mechanism of endothelial nitric oxide synthase phosphorylation and activation by tentacle extract from the jellyfish Cyanea capillata. PeerJ 5:e3172 https://doi.org/10.7717/peerj.3172
A transdisciplinary approach to the initial validation of a single cell protein as an alternative protein source for use in aquafeeds
The human population is growing and, globally, we must meet the challenge of increased protein needs required to feed this population. Single cell proteins (SCP), when coupled to aquaculture production, offer a means to ensure future protein needs can be met without direct competition with food for people. To demonstrate a given type of SCP has potential as a protein source for use in aquaculture feed, a number of steps need to be validated including demonstrating that the SCP is accepted by the species in question, leads to equivalent survival and growth, does not result in illness or other maladies, is palatable to the consumer, is cost effective to produce and can easily be incorporated into diets using existing technology. Here we examine white shrimp (Litopenaeus vannamei) growth and consumer taste preference, smallmouth grunt (Haemulon chrysargyreum) growth, survival, health and gut microbiota, and Atlantic salmon (Salmo salar) digestibility when fed diets that substitute the bacterium Methylobacterium extorquens at a level of 30% (grunts), 100% (shrimp), or 55% (salmon) of the fishmeal in a compound feed. In each of these tests, animals performed equivalently when fed diets containing M. extorquens as when fed a standard aquaculture diet. This transdisciplinary approach is a first validation of this bacterium as a potential SCP protein substitute in aquafeeds. Given the ease to produce this SCP through an aerobic fermentation process, the broad applicability for use in aquaculture indicates the promise of M. extorquens in leading toward greater food security in the future.
Tlusty et al. (2017) A transdisciplinary approach to the initial validation of a single cell protein as an alternative protein source for use in aquafeeds. PeerJ 5:e3170 https://doi.org/10.7717/peerj.3170
Are anti-ganglioside antibodies associated with proventricular dilatation disease in birds?
The identification of Parrot bornaviruses (PaBV) in psittacine birds with proventricular dilatation disease (PDD) has not been sufficient to explain the pathogenesis of this fatal disease, since not all infected birds develop clinical signs. Although the most accepted theory indicates that PaBV directly triggers an inflammatory response in this disease, another hypothesis suggests the disease is triggered by autoantibodies targeting neuronal gangliosides, and PDD might therefore resemble Guillain-Barré Syndrome (GBS) in its pathogenesis. Experimental inoculation of pure gangliosides and brain-derived ganglioside extracts were used in two different immunization studies. The first study was performed on 17 healthy chickens (Gallus gallus domesticus): 11 chickens were inoculated with a brain ganglioside extract in Freund’s complete adjuvant (FCA) and six chickens inoculated with phosphate-buffered saline. A second study was performed five healthy quaker parrots (Myiopsitta monachus) that were divided into three groups: Two quaker parrots received purified gangliosides in FCA, two received a crude brain extract in FCA, and one control quaker parrot received FCA alone. One chicken developed difficult in walking. Histologically, only a mild perivascular and perineural lymphocytic infiltrate in the proventriculus. Two quaker parrots (one from each treatment group) had mild lymphoplasmacytic encephalitis and myelitis. However, none of the quaker parrots developed myenteric ganglioneuritis, suggesting that autoantibodies against gangliosides in birds are not associated with a condition resembling PDD.
Leal de Araujo et al. (2017) Are anti-ganglioside antibodies associated with proventricular dilatation disease in birds?. PeerJ 5:e3144 https://doi.org/10.7717/peerj.3144
Aspects of gorgonopsian paleobiology and evolution: insights from the basicranium, occiput, osseous labyrinth, vasculature, and neuroanatomy
Synapsida, the clade including therapsids and thus also mammals, is one of the two major branches of amniotes. Organismal design, with modularity as a concept, offers insights into the evolution of therapsids, a group that experienced profound anatomical transformations throughout the past 270 Ma, eventually leading to the evolution of the mammalian bauplan. However, the anatomy of some therapsid groups remains obscure. Gorgonopsian braincase anatomy is poorly known and many anatomical aspects of the brain, cranial nerves, vasculature, and osseous labyrinth, remain unclear. We analyzed two gorgonopsian specimens, GPIT/RE/7124 and GPIT/RE/7119, using propagation phase contrast synchrotron micro-computed tomography. The lack of fusion between many basicranial and occipital bones in GPIT/RE/7124, which is an immature specimen, allowed us to reconstruct its anatomy and ontogenetic sequence, in comparison with the mature GPIT/RE/7119, in great detail. We explored the braincase and rendered various skull cavities. Notably, we found that there is a separate ossification between what was previously referred to as the “parasphenoid” and the basioccipital. We reinterpreted this element as a posterior ossification of the basisphenoid: the basipostsphenoid. Moreover, we show that the previously called “parasphenoid” is in fact the co-ossification of the dermal parasphenoid and the endochondral basipresphenoid. In line with previous descriptions, the anatomy of the osseous labyrinth is rendered in detail, revealing a unique discoid morphology of the horizontal semicircular canal, rather than toroidal, probably due to architectural constraints of the ossification of the opisthotic and supraoccipital. In addition, the orientation of the horizontal semicircular canal suggests that gorgonopsians had an anteriorly tilted alert head posture. The morphology of the brain endocast is in accordance with the more reptilian endocast shape of other non-mammaliaform neotherapsids.
Araújo et al. (2017) Aspects of gorgonopsian paleobiology and evolution: insights from the basicranium, occiput, osseous labyrinth, vasculature, and neuroanatomy. PeerJ 5:e3119 https://doi.org/10.7717/peerj.3119
Intra-specific variation and allometry of the skull of Late Cretaceous side-necked turtle Bauruemys elegans (Pleurodira, Podocnemididae) and how to deal with morphometric data in fossil vertebrates
Background Previous quantitative studies on Bauruemys elegans (Suárez, 1969) shell variation, as well as the taphonomic interpretation of its type locality, have suggested that all specimens collected in this locality may have belonged to the same population. We rely on this hypothesis in a morphometric study of the skull. Also, we tentatively assessed the eating preference habits differentiation that might be explained as due to ontogenetic changes. Methods We carried out an ANOVA testing 29 linear measurements from 21 skulls of B. elegans taken by using a caliper and through images, using the ImageJ software. First, a Principal Components Analysis (PCA) was performed with 27 measurements (excluding total length and width characters; =raw data) in order to visualize the scatter plots based on the form variance only. Then, a second PCA was carried out using ratios of length and width of each original measurement to assess shape variation among individuals. Finally, original measurements were log-transformed to describe allometries over ontogeny. Results No statistical differences were found between caliper and ImageJ measurements. The first three PCs of the PCA with raw data comprised 70.2% of the variance. PC1 was related to size variation and all others related to shape variation. Two specimens plotted outside the 95% ellipse in PC1∼PC2 axes. The first three PCs of the PCA with ratios comprised 64% of the variance. When considering PC1∼PC2, all specimens plotted inside the 95% ellipse. In allometric analysis, five measurements were positively allometric, 19 were negatively allometric and three represented enantiometric allometry. Many bones of the posterior and the lateral emarginations lengthen due to increasing size, while jugal and the quadratojugal decrease in width. Discussion ImageJ is useful in replacing caliper since there was no statistical differences. Yet iterative imputation is more appropriate to deal with missing data in PCA. Some specimens show small differences in form and shape. Form differences were interpreted as occuring due to ontogeny, whereas shape differences are related to feeding changes during growth. Moreover, all outlier specimens are crushed and/or distorted, thus the form/shape differences may be partially due to taphonomy. The allometric lengthening of the parietal, quadrate, squamosal, maxilla, associated with the narrowing of jugal and quadratojugal may be related to changes in feeding habit between different stages of development. This change in shape might represent a progressive skull stretching and enlargement of posterior and lateral emargination during ontogeny, and consequently, the increment of the feeding-apparatus musculature. Smaller individuals may have fed on softer diet, whereas larger ones probably have had a harder diet, as seen in some living species of Podocnemis. We conclude that the skull variation might be related to differences in feeding habits over ontogeny in B. elegans.
Mariani et al. (2017) Intra-specific variation and allometry of the skull of Late Cretaceous side-necked turtle Bauruemys elegans (Pleurodira, Podocnemididae) and how to deal with morphometric data in fossil vertebrates. PeerJ 5:e2890 https://doi.org/10.7717/peerj.2890
The impacts of climate change on the abundance and distribution of the Spotted Wing Drosophila (Drosophila suzukii) in the United States and Canada
D. suzukii is a relatively recent and destructive pest species to the North American soft-skinned fruit industry. Understanding this species’ potential to shift in abundance and range due to changing climate is an important part of an effective mitigation and management strategy. We parameterized a temperature-driven D. suzukii population dynamics model using temperature data derived from several Global Circulation Models (CMIP5) with a range of relative concentration pathway (RCP) predictions. Mean consensus between the models suggest that without adaptation to both higher prolonged temperatures and higher short-term temperature events D. suzukii population levels are likely to drop in currently higher-risk regions. The potential drop in population is evident both as time progresses and as the severity of the RCP scenario increases. Some regions, particularly in northern latitudes, may experience increased populations due to milder winter and more developmentally-ideal summer conditions, but many of these regions are not currently known for soft-skinned fruit production and so the effects of this population increase may not have a significant impact.
Langille et al. (2017) The impacts of climate change on the abundance and distribution of the Spotted Wing Drosophila (Drosophila suzukii) in the United States and Canada. PeerJ 5:e3192 https://doi.org/10.7717/peerj.3192
Seasonally distinct taxonomic and functional shifts in macroinvertebrate communities following dam removal
Dam removal is an increasingly popular restoration tool, but our understanding of ecological responses to dam removal over time is still in the early stages. We quantified seasonal benthic macroinvertebrate density, taxonomic composition, and functional traits for three years after lowhead dam removal in three reaches of the Olentangy River (Ohio, USA): two upstream of former dam (one restored, one unrestored), and one downstream of former dam. Macroinvertebrate community density, generic richness, and Shannon–Wiener diversity decreased between ∼9 and ∼15 months after dam removal; all three variables consistently increased thereafter. These threshold responses were dependent on reach location: density and richness increased ∼15 months after removal in upstream reaches versus ∼19 months downstream of the former dam. Initial macroinvertebrate density declines were likely related to seasonality or life-history characteristics, but density increased up to 2.27× from year to year in three out of four seasons (late autumn, early spring, summer) across all reaches. Macroinvertebrate community composition was similar among the three reaches, but differed seasonally based on non-metric multidimensional scaling (NMDS) and analysis of similarity (ANOSIM). Seasonal differences among communities tended to decrease after dam removal. We detected community-wide shifts in functional traits such as multivoltinism, depositional habitat use, burrowing, and collector-gatherer feeding mode. We observed that these traits were expressed most strongly with Chironomidae, which was the most abundant family. Our results suggest that seasonal environmental conditions can play a role in the response and recovery of macroinvertebrate communities—often used to monitor ecosystem condition—following dam removal. In particular, macroinvertebrate density and diversity can show recovery after dam removal, especially in seasons when macroinvertebrate density is typically lowest, with concomitant changes to functional trait abundance. Thus, we recommend scientists and managers consider responses to dam removal throughout the year. Further, similar density, generic richness, and functional traits among reaches suggest that channel restoration after dam removal may initially have equivocal effects on invertebrate communities.
Sullivan et al. (2017) Seasonally distinct taxonomic and functional shifts in macroinvertebrate communities following dam removal. PeerJ 5:e3189 https://doi.org/10.7717/peerj.3189
The association between continual, year-round hunting and bellowing rate of bison bulls during the rut
The impact of hunting (selective harvest, trophy hunting) on the demography of mammals is well documented. However, despite continual year-round hunting of bison in some populations, little is known about how the behavior of survivors may be altered. Therefore, in this initial study, we used focal-animal observations in adjacent populations of continually hunted and protected Plains bison (Bison bison bison) in western South Dakota, to examine the potential impact of hunting on bellowing rate—an important behavior that serves to intimidate rival bulls and potentially influences mate choice by females. In addition to hunting, we investigated how the number of attendant males, number of adult females, group size, and number of days from the start of rut influenced bellowing rate. Bulls bellowed an order of magnitude more often in the protected population than in the hunted populations, whereas bellowing rate was not significantly different in the hunted populations. Hunting was significantly and negatively associated with bellowing rate, while all other predictors were found to be positively associated with bellowing rate. Furthermore, the impact of hunting on bellowing rate became more pronounced (i.e., dampened bellowing rate more strongly) as the number of attendant males increased. Changes in bellowing behavior of bulls (and possibly mate choice by cows) can alter breeding opportunities. Therefore, our data suggest the need for studies with broader-scale geographical and temporal replication to determine the extent that continual year-round hunting has on bellowing rate of bison during the rut. If reduced bellowing is associated with human hunting on a larger scale, then wildlife managers may need to adjust hunting rate and duration, timing (season), and the time lag between hunting events in order to insure that bison are able to express their full repertoire of natural mating behaviors.
Sarno et al. (2017) The association between continual, year-round hunting and bellowing rate of bison bulls during the rut. PeerJ 5:e3153 https://doi.org/10.7717/peerj.3153