Putative carboxylesterase gene identification and their expression patterns in Hyphantria cunea (Drury)
The olfactory system of insects is important for behavioral activities as it recognizes internal and external volatile stimuli in the environment. Insect odorant degrading enzymes (ODEs), including antennal-specific carboxylesterases (CXEs), are known to degrade redundant odorant molecules or to hydrolyze important olfactory sex pheromone components and plant volatiles. Compared to many well-studied Type-I sex pheromone-producing lepidopteran species, the molecular mechanisms of the olfactory system of Type-II sex pheromone-producing Hyphantria cunea (Drury) remain poorly understood. In the current study, we first identified a total of ten CXE genes based on our previous H. unea antennal transcriptomic data. We constructed a phylogenetic tree to evaluate the relationship of HcunCXEs with other insects’ CXEs, and used quantitative PCR to investigate the gene expression of H. cunea CXEs (HcunCXEs). Our results indicate that HcunCXEs are highly expressed in antennae, legs and wings, suggesting a potential function in degrading sex pheromone components, host plant volatiles, and other xenobiotics. This study not only provides a theoretical basis for subsequent olfactory mechanism studies on H. cunea, but also offers some new insights into functions and evolutionary characteristics of CXEs in lepidopteran insects. From a practical point of view, these HcunCXEs might represent meaningful targets for developing behavioral interference control strategies against H. cunea.
Ye et al. (2021) Putative carboxylesterase gene identification and their expression patterns in Hyphantria cunea (Drury). PeerJ 9:e10919 https://doi.org/10.7717/peerj.10919
Ontogeny of highly variable ceratitid ammonoids from the Anisian (Middle Triassic)
Ammonoids reached their greatest diversity during the Triassic period. In the early Middle Triassic (Anisian) stage, ammonoid diversity was dominated by representatives of the family Ceratitidae. High taxonomic diversity can, however, be decoupled from their morphologic disparity. Due to its high phenotypic variability, the high diversity of ceratitids of the Anisian of Nevada was initially assumed to be caused by artificial over-splitting. This study aims to contribute data to settle this issue by applying geometric morphometrics methods, using landmarks and semi-landmarks, in the study of ontogenetic cross-sections of ammonoids for the first time. The results reveal that alterations in ontogenetic trajectories, linked to heterochronic processes, lead to the morphologic diversification of the species studied herein. Our knowledge, based on these ontogenetic changes, challenge the traditional treatment of species using solely adult characters for their distinction. This study furthermore demonstrates that the high diversity of the Anisian ammonoid assemblages of Nevada based on the traditional nomenclatoric approach is regarded to be reasonably accurate.
Bischof et al. (2021) Ontogeny of highly variable ceratitid ammonoids from the Anisian (Middle Triassic). PeerJ 9:e10931 https://doi.org/10.7717/peerj.10931
Genome-wide identification and expression analysis of ADP-ribosylation factors associated with biotic and abiotic stress in wheat (Triticum aestivum L.)
The ARF gene family plays important roles in intracellular transport in eukaryotes and is involved in conferring tolerance to biotic and abiotic stresses in plants. To explore the role of these genes in the development of wheat (Triticum aestivum L.), 74 wheat ARF genes (TaARFs; including 18 alternate transcripts) were identified and clustered into seven sub-groups. Phylogenetic analysis revealed that TaARFA1 sub-group genes were strongly conserved. Numerous cis-elements functionally associated with the stress response and hormones were identified in the TaARFA1 sub-group, implying that these TaARFs are induced in response to abiotic and biotic stresses in wheat. According to available transcriptome data and qRT-PCR analysis, the TaARFA1 genes displayed tissue-specific expression patterns and were regulated by biotic stress (powdery mildew and stripe rust) and abiotic stress (cold, heat, ABA, drought and NaCl). Protein interaction network analysis further indicated that TaARFA1 proteins may interact with protein phosphatase 2C (PP2C), which is a key protein in the ABA signaling pathway. This comprehensive analysis will be useful for further functional characterization of TaARF genes and the development of high-quality wheat varieties.
Li et al. (2021) Genome-wide identification and expression analysis of ADP-ribosylation factors associated with biotic and abiotic stress in wheat (Triticum aestivum L.). PeerJ 9:e10963 https://doi.org/10.7717/peerj.10963
Trophic niche differentiation and utilisation of food resources in Collembola is altered by rainforest conversion to plantation systems
Intensively managed monoculture plantations are increasingly replacing natural forests across the tropics resulting in changes in ecological niches of species and communities, and in ecosystem functioning. Collembola are among the most abundant arthropods inhabiting the belowground system sensitively responding to changes in vegetation and soil conditions. However, most studies on the response of Collembola to land-use change were conducted in temperate ecosystems and focused on shifts in community composition or morphological traits, while parameters more closely linked to ecosystem functioning, such as trophic niches, received little attention. Here, we used stable isotope analysis (13C and 15N) to investigate changes in the trophic structure and use of food resources by Collembola in Jambi province (Sumatra, Indonesia), a region that experienced strong deforestation in the last decades. Isotopic values of Collembola from 32 sites representing four land-use systems were analyzed (rainforest, rubber agroforest, rubber (Hevea brasiliansis) and oil palm (Elaeis guineensis) monoculture plantations). Across Collembola species Δ13C values were highest in rainforest suggesting more pronounced processing of litter resources by microorganisms and consumption of these microorganisms by Collembola in this system. Lower Δ13C values, but high Δ13C variation in Collembola in oil palm plantations indicated that Collembola shifted towards herbivory and used more variable resources in this system. Small range in Δ15N values in Collembola species in monoculture plantations in comparison to rainforest indicated that conversion of rainforest into plantations is associated with simplification in the trophic structure of Collembola communities. This was further confirmed by generally lower isotopic niche differentiation among species in plantations. Across the studied ecosystems, atmobiotic species (Symphypleona and Paronellidae) occupied the lowest, whereas euedaphic Collembola species occupied the highest trophic position, resembling patterns in temperate forests. Some species of Paronellidae in rainforest and jungle rubber had Δ15N values below those of leaf litter suggesting algivory (Salina sp.1, Callyntrura sp.1 and Lepidonella sp.1), while a dominant species, Pseudosinella sp.1, had the highest Δ15N values in most of the land-use systems suggesting that this species at least in part lives as predator or scavenger. Overall, the results suggest that rainforest conversion into plantation systems is associated with marked shifts in the structure of trophic niches in soil and litter Collembola with potential consequences for ecosystem functioning and food-web stability.
Susanti et al. (2021) Trophic niche differentiation and utilisation of food resources in Collembola is altered by rainforest conversion to plantation systems. PeerJ 9:e10971 https://doi.org/10.7717/peerj.10971
Formalin-induced pain prolongs sub- to supra-second time estimation in rats
Background Temporal estimation can be influenced by pain, which is a complex psychological and physiological phenomenon. However, the time range in which perception is most sensitive to pain remains unclear. Methods In the present study, we explored the effects of acute inflammatory pain on time perception in the sub- to supra-second (0.6–2.4-s) and supra-second (2–8-s) ranges in rats. Plantar formalin injection was used to induce acute inflammatory pain, and a temporal bisection task was used to measure time perception. Task test sessions were held for five consecutive days (one per day): the day before injection (baseline), immediately after injection, and the three post-injection days. The point of subjective equality (PSE, which reflects the subjective duration) and Weber fraction (which reflects temporal sensitivity) were calculated and analysed. Results In the 0.6–2.4-s range, the PSE was significantly lower, indicating prolonged subjective duration, in the formalin group relative to the saline group (p = 0.049) immediately after injection. Formalin-induced pain also tended to lengthened time perception in the 0.6–2.4-s range on post-injection days 2 (p = 0.06) and 3 (p = 0.054). In the 2–8-s range, formalin injection did not affect the PSE or Weber fraction. Conclusions The enhanced effect of pain on temporal perception in the sub- to supra-second range is observed in this study and this effect is attenuated with the prolongation of estimated time, even in rats.
Liu et al. (2021) Formalin-induced pain prolongs sub- to supra-second time estimation in rats. PeerJ 9:e11002 https://doi.org/10.7717/peerj.11002
Predictors of treatment failure during the first year in newly diagnosed type 2 diabetes patients: a retrospective, observational study
Background Diabetes patients who fail to achieve early glycemic control may increase the future risk of complications and mortality. The aim of the study was to identify factors that predict treatment failure (TF) during the first year in adults with newly diagnosed type 2 diabetes mellitus (T2DM). Methods This retrospective cohort study conducted at a medical center in Taiwan enrolled 4,282 eligible patients with newly diagnosed T2DM between 2002 and 2017. Data were collected from electronic medical records. TF was defined as the HbA1c value >7% at the end of 1-year observation. A subgroup analysis of 2,392 patients with baseline HbA1c ≥8% was performed. Multivariable logistic regression analysis using backward elimination was applied to establish prediction models. Results Of all study participants, 1,439 (33.6%) were classified as TF during the first year. For every 1% increase in baseline HbA1c, the risk of TF was 1.17 (95% CI 1.15–1.20) times higher. Patients with baseline HbA1c ≥8% had a higher rate of TF than those with HbA1c <8% (42.0 vs 23.0%, p < 0.001). Medication adherence, self-monitoring of blood glucose (SMBG), regular exercise, gender (men), non-insulin treatment, and enrollment during 2010–2017 predicted a significant lower risk of TF in both of the primary and subgroup models. Conclusions Newly diagnosed diabetes patients with baseline HbA1c ≥8% did have a much higher rate of TF during the first year. Subgroup analysis for them highlights the important predictors of TF, including medication adherence, performing SMBG, regular exercise, and gender, in achieving glycemic control.
Sia et al. (2021) Predictors of treatment failure during the first year in newly diagnosed type 2 diabetes patients: a retrospective, observational study. PeerJ 9:e11005 https://doi.org/10.7717/peerj.11005
A psychrometric model to assess the biological decay of the SARS-CoV-2 virus in aerosols
There is increasing evidence that the 2020 COVID-19 pandemic has been influenced by variations in air temperature and humidity. However, the impact that these environmental parameters have on survival of the SARS-CoV-2 virus has not been fully characterised. Therefore, an analytical study was undertaken using published data to develop a psychrometric model to assess the biological decay rate of the virus in aerosols. This revealed that it is possible to describe with reasonable accuracy (R2 = 0.718, p < 0.001) the biological decay constant for the SARS-CoV-2 virus using a regression model with enthalpy, vapour pressure and specific volume as predictors. Applying this to historical meteorological data from London, Paris and Milan over the pandemic period, produced results which indicate that the average half-life of the virus in aerosols outdoors was in the region 13–22 times longer in March 2020, when the outbreak was accelerating, than it was in August 2020 when epidemic in Europe was at its nadir. However, indoors, this variation is likely to be much less. As such, this suggests that changes in virus survivability due the variations in the psychrometric qualities of the air might influence the transmission of SARS-CoV-2.
Environmental Contamination and Remediation
Beggs et al. (2021) A psychrometric model to assess the biological decay of the SARS-CoV-2 virus in aerosols. PeerJ 9:e11024 https://doi.org/10.7717/peerj.11024
A heat-shock 20 protein isolated from watermelon (ClHSP22.8) negatively regulates the response of Arabidopsis to salt stress via multiple signaling pathways
Heat-shock protein 20s (HSP20) were initially shown to play a role during heat shock stress; however, recent data indicated that HSP20 proteins are also involved in abiotic stress in plants. Watermelon is known to be vulnerable to various stressors; however, HSP20 proteins have yet to be investigated and characterized in the watermelon. In a previous study, we identified a negative regulator of salt stress response from watermelon: ClHSP22.8, a member of the HSP20 family. Quantitative real-time PCR (qRT-PCR) and promoter::β-glucuronidase (GUS) analysis revealed that ClHSP22.8 was expressed widely in a range of different tissues from the watermelon, but particularly in the roots of 7-day-old seedlings and flowers. Furthermore, qRT-PCR and GUS staining showed that the expression of ClHSP22.8 was significantly repressed by exogenous abscisic acid (ABA) and salt stress. The over-expression of ClHSP22.8 in Arabidopsis lines resulted in hypersensitivity to ABA and reduced tolerance to salt stress. Furthermore, the expression patterns of key regulators associated with ABA-dependent and independent pathways, and other stress-responsive signaling pathways, were also repressed in transgenic lines that over-expressed ClHSP22.8. These results indicated that ClHSP22.8 is a negative regulator in plant response to salt stress and occurs via ABA-dependent and independent, and other stress-responsive signaling pathways.
He et al. (2021) A heat-shock 20 protein isolated from watermelon (ClHSP22.8) negatively regulates the response of Arabidopsis to salt stress via multiple signaling pathways. PeerJ 9:e10524 https://doi.org/10.7717/peerj.10524
Mammal-exclusion fencing improves the nesting success of an endangered native Hawaiian waterbird
Invasive predator control is often critical to improving the nesting success of endangered birds, but methods of control vary in cost and effectiveness. Poison-baiting or trapping and removal are relatively low-cost, but may have secondary impacts on non-target species, and may not completely exclude mammals from nesting areas. Mammal-exclusion fencing has a substantial up-front cost, but due to cost savings over the lifetime of the structure and the complete exclusion of mammalian predators, this option is increasingly being utilized to protect threatened species such as ground-nesting seabirds. However, non-mammalian predators are not excluded by these fences and may continue to impact nesting success, particularly in cases where the fence is designed for the protection of waterbirds, open to an estuary or wetland on one side. Thus, there remains a research gap regarding the potential gains in waterbird nesting success from the implementation of mammal-exclusion fencing in estuarine systems. In this study, we compared the nesting success of endangered Hawaiian Stilts (Ae‘o; Himantopus mexicanus knudseni) within a mammal-exclusion fence to that of breeding pairs in a nearby wetland where trapping was the sole means for removing invasive mammals. We predicted success would be greater for breeding pairs inside the exclusion fence and the hatchlings inside the enclosure would spend more time in the nesting area than hatchlings at the unfenced site. During a single breeding season following construction of a mammal-exclusion fence, we used motion-activated game cameras to monitor nests at two sites, one site with mammal-exclusion fencing and one site without. Clutch sizes and hatch rates were significantly greater at the fenced site than the unfenced site, but time spent by chicks in the nesting area did not differ between sites. These results add to the mounting body of evidence that demonstrates the effectiveness of mammal-exclusion fencing in protecting endangered birds and suggests it can aid endangered Hawaiian waterbirds toward recovery. These results also suggest that the single greatest predatory threat to the Hawaiian Stilt may be invasive mammals, despite a host of known non-mammalian predators including birds, crabs, turtles, and bullfrogs, as the complete exclusion of mammals resulted in significant gains in nesting success. As additional fences are built, future studies are necessary to compare nesting success among multiple sites and across multiple seasons to determine potential gains in fledging success and recruitment.
Christensen et al. (2021) Mammal-exclusion fencing improves the nesting success of an endangered native Hawaiian waterbird. PeerJ 9:e10722 https://doi.org/10.7717/peerj.10722
Homeostatic responses and growth of Leymus chinensis under incrementally increasing saline-alkali stress
Despite considerable tolerance to salt and alkali stress, Leymus chinensis populations on the southwestern Songnen Plain in northern China are threatened by increasing soil salinity and alkalinity. To explore the species’ responses to saline-alkali stress, we grew it in substrates with varying concentrations of nitrogen (N) and phosphorus (P) while applying varying levels of saline-alkali stress (increasing in 14-, 17- or 23 -day intervals). We measured the plants’ contents of N and P, and the N:P ratio, and calculated their homeostasis indices (HN, HP and HN:P) under each nutrient and saline-alkali stress treatment. The N content was found to be more sensitive to saline-alkali stress than the P content. The N and P contents were highest and the N:P ratio was stable at pH 8.4. At both pH 8.1 and 8.4, HN:P> HN > HP, but the indices and their relations differed at other pH values. Exposure to saline-alkali stress for the 14-day incremental interval had weaker effects on the plants. Rapid changes in salinity-alkalinity weakened both the positive effects of the weakly alkaline conditions (pH 7.5–8.4) and the negative effects of more strongly alkaline conditions (pH 8.7 or 9.3) on L. chinensis. When L. chinensis plants lack N, applying N fertilizer will be extremely efficient. The optimal concentrations of N and P appeared to be 16 and 1.2 mmol/L, respectively. When the L. chinensis plants were N- and P-limited, the specific growth rate correlated positively with N:P, when limited by N it correlated positively with the environmental N concentration, and when limited by P it was weakly positively correlated with the environmental P concentration.
Li et al. (2021) Homeostatic responses and growth of Leymus chinensis under incrementally increasing saline-alkali stress. PeerJ 9:e10768 https://doi.org/10.7717/peerj.10768