High fat-fed GPR55 null mice display impaired glucose tolerance without concomitant changes in energy balance or insulin sensitivity but are less responsive to the effects of the cannabinoids rimonabant or Δ(9)-tetrahydrocannabivarin on weight gain
Background The insulin-sensitizing phytocannabinoid, Δ(9)-tetrahydrocannabivarin (THCV) can signal partly via G-protein coupled receptor-55 (GPR55 behaving as either an agonist or an antagonist depending on the assay). The cannabinoid receptor type 1 (CB1R) inverse agonist rimonabant is also a GPR55 agonist under some conditions. Previous studies have shown varied effects of deletion of GPR55 on energy balance and glucose homeostasis in mice. The contribution of signalling via GPR55 to the metabolic effects of THCV and rimonabant has been little studied. Methods In a preliminary experiment, energy balance and glucose homeostasis were studied in GPR55 knockout and wild-type mice fed on both standard chow (to 20 weeks of age) and high fat diets (from 6 to 15 weeks of age). In the main experiment, all mice were fed on the high fat diet (from 6 to 14 weeks of age). In addition to replicating the preliminary experiment, the effects of once daily administration of THCV (15 mg kg−1 po) and rimonabant (10 mg kg−1 po) were compared in the two genotypes. Results There was no effect of genotype on absolute body weight or weight gain, body composition measured by either dual-energy X-ray absorptiometry or Nuclear Magnetic Resonance (NMR), fat pad weights, food intake, energy expenditure, locomotor activity, glucose tolerance or insulin tolerance in mice fed on chow. When the mice were fed a high fat diet, there was again no effect of genotype on these various aspects of energy balance. However, in both experiments, glucose tolerance was worse in the knockout than the wild-type mice. Genotype did not affect insulin tolerance in either experiment. Weight loss in rimonabant- and THCV-treated mice was lower in knockout than in wild-type mice, but surprisingly there was no detectable effect of genotype on the effects of the drugs on any aspect of glucose homeostasis after taking into account the effect of genotype in vehicle-treated mice. Conclusions Our two experiments differ from those reported by others in finding impaired glucose tolerance in GPR55 knockout mice in the absence of any effect on body weight, body composition, locomotor activity or energy expenditure. Nor could we detect any effect of genotype on insulin tolerance, so the possibility that GPR55 regulates glucose-stimulated insulin secretion merits further investigation. By contrast with the genotype effect in untreated mice, we found that THCV and rimonabant reduced weight gain, and this effect was in part mediated by GPR55.
Wargent et al. (2020) High fat-fed GPR55 null mice display impaired glucose tolerance without concomitant changes in energy balance or insulin sensitivity but are less responsive to the effects of the cannabinoids rimonabant or Δ(9)-tetrahydrocannabivarin on weight gain. PeerJ 8:e9811 https://doi.org/10.7717/peerj.9811
Effects of 12-week cadence retraining on impact peak, load rates and lower extremity biomechanics in running
Background Excessive impact peak forces and vertical load rates are associated with running injuries and have been targeted in gait retraining studies. This study aimed to determine the effects of 12-week cadence retraining on impact peak, vertical load rates and lower extremity biomechanics during running. Methods Twenty-four healthy male recreational runners were randomised into either a 12-week cadence retraining group (n = 12), which included those who ran with a 7.5% increase in preferred cadence, or a control group (n = 12), which included those who ran without any changes in cadence. Kinematics and ground reaction forces were recorded simultaneously to quantify impact force variables and lower extremity kinematics and kinetics. Results Significantly decreased impact peak (1.86 ± 0.30 BW vs. 1.67 ± 0.27 BW, P = 0.003), vertical average load rates (91.59 ± 18.91 BW/s vs. 77.31 ± 15.12 BW/s, P = 0.001) and vertical instantaneous load rates (108.8 ± 24.5 BW/s vs. 92.8 ± 18.5 BW/s, P = 0.001) were observed in the cadence retraining group, while no significant differences were observed in the control group. Foot angles (18.27° ± 5.59° vs. 13.74° ± 2.82°, P = 0.003) and vertical velocities of the centre of gravity (CoG) (0.706 ± 0.115 m/s vs. 0.652 ± 0.091 m/s, P = 0.002) significantly decreased in the cadence retraining group at initial contact, but not in the control group. In addition, vertical excursions of the CoG (0.077 ± 0.01 m vs. 0.069 ± 0.008 m, P = 0.002) and peak knee flexion angles (38.6° ± 5.0° vs. 36.5° ± 5.5°, P < 0.001) significantly decreased whilst lower extremity stiffness significantly increased (34.34 ± 7.08 kN/m vs. 38.61 ± 6.51 kN/m, P = 0.048) in the cadence retraining group. However, no significant differences were observed for those variables in the control group. Conclusion Twelve-week cadence retraining significantly increased the cadence of the cadence retraining group by 5.7%. This increased cadence effectively reduced impact peak and vertical average/instantaneous load rates. Given the close relationship between impact force variables and running injuries, increasing the cadence as a retraining method may potentially reduce the risk of impact-related running injuries.
Wang et al. (2020) Effects of 12-week cadence retraining on impact peak, load rates and lower extremity biomechanics in running. PeerJ 8:e9813 https://doi.org/10.7717/peerj.9813
Application of carbon dioxide to the skin and muscle oxygenation of human lower-limb muscle sites during cold water immersion
Background Cold therapy has the disadvantage of inducing vasoconstriction in arterial and venous capillaries. The effects of carbon dioxide (CO2) hot water depend mainly on not only cutaneous vasodilation but also muscle vasodilation. We examined the effects of artificial CO2 cold water immersion (CCWI) on skin oxygenation and muscle oxygenation and the immersed skin temperature. Subjects and Methods Fifteen healthy young males participated. CO2-rich water containing CO2 >1,150 ppm was prepared using a micro-bubble device. Each subject’s single leg was immersed up to the knee in the CO2-rich water (20 °C) for 15 min, followed by a 20-min recovery period. As a control study, a leg of the subject was immersed in cold tap-water at 20 °C (CWI). The skin temperature at the lower leg under water immersion (Tsk-WI) and the subject’s thermal sensation at the immersed and non-immersed lower legs were measured throughout the experiment. We simultaneously measured the relative changes of local muscle oxygenation/deoxygenation compared to the basal values (Δoxy[Hb+Mb], Δdeoxy[Hb+Mb], and Δtotal[Hb+Mb]) at rest, which reflected the blood flow in the muscle, and we measured the tissue O2 saturation (StO2) by near-infrared spectroscopy on two regions of the tibialis anterior (TA) and gastrocnemius (GAS) muscles. Results Compared to the CWI results, the Δoxy[Hb+Mb] and Δtotal[Hb+Mb] in the TA muscle at CCWI were increased and continued at a steady state during the recovery period. In GAS muscle, the Δtotal[Hb+Mb] and Δdeoxy[Hb+Mb] were increased during CCWI compared to CWI. Notably, StO2values in both TA and GAS muscles were significantly increased during CCWI compared to CWI. In addition, compared to the CWI, a significant decrease in Tsk at the immersed leg after the CCWI was maintained until the end of the 20-min recovery, and the significant reduction continued. Discussion The combination of CO2 and cold water can induce both more increased blood inflow into muscles and volume-related (total heme concentration) changes in deoxy[Hb+Mb] during the recovery period. The Tsk-WI stayed lower with the CCWI compared to the CWI, as it is associated with vasodilation by CO2.
Yoshimura et al. (2020) Application of carbon dioxide to the skin and muscle oxygenation of human lower-limb muscle sites during cold water immersion. PeerJ 8:e9785 https://doi.org/10.7717/peerj.9785
Chemotype classification and biomarker screening of male Eucommia ulmoides Oliv. flower core collections using UPLC-QTOF/MS-based non-targeted metabolomics
Background In the Chinese health care industry, male Eucommia ulmoides Oliv. flowers are newly approved as a raw material of functional food. Core collections have been constructed from conserved germplasm resources based on phenotypic traits and molecular markers. However, little is known about these collections’ phytochemical properties. This study explored the chemical composition of male E. ulmoides flowers, in order to provide guidance in the quality control, sustainable cultivation, and directional breeding of this tree species. Methods We assessed the male flowers from 22 core collections using ultra-performance liquid chromatography and quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) non-targeted metabolomics, and analyzed them using multivariate statistical methods including principal component analysis (PCA), hierarchical cluster analysis (HCA), and orthogonal partial least squares discriminant analysis (OPLS-DA). Results We annotated a total of 451 and 325 metabolites in ESI+ and ESI− modes, respectively, by aligning the mass fragments of the secondary mass spectra with those in the database. Four chemotypes were well established using the ESI+ metabolomics data. Of the 29 screened biomarkers, 21, 6, 19, and 5 markers corresponded to chemotypes I, II, III, and IV, respectively. More than half of the markers belonged to flavonoid and amino acid derivative classes. Conclusion Non-targeted metabolomics is a suitable approach to the chemotype classification and biomarker screening of male E. ulmoides flower core collections. We first evaluated the metabolite profiles and compositional variations of male E. ulmoides flowers in representative core collections before establishing possible chemotypes and significant biomarkers denoting the variations. We used genetic variations to infer the metabolite compositional variations of male E. ulmoides flower core collections instead of using the geographical origins of the germplasm resources. The newly proposed biomarkers sufficiently classified the chemotypes to be applied for germplasm resource evaluation.
Liu et al. (2020) Chemotype classification and biomarker screening of male Eucommia ulmoides Oliv. flower core collections using UPLC-QTOF/MS-based non-targeted metabolomics. PeerJ 8:e9786 https://doi.org/10.7717/peerj.9786
Human granulocyte-colony stimulating factor (G-CSF)/stem cell factor (SCF) fusion proteins: design, characterization and activity
Background Stem cell factor (SCF) and granulocyte-colony stimulating factor (G-CSF) are well-characterized vital hematopoietic growth factors that regulate hematopoiesis. G-CSF and SCF synergistically exhibit a stimulatory effect on hematopoietic progenitors. The combination of G-CSF and SCF has been used for mobilization of peripheral blood progenitor cells in cancer and non-cancerous conditions. To overcome challenges connected with the administration of two cytokines, we developed two fusion proteins composed of human SCF and human G-CSF interspaced by an alpha-helix-forming peptide linker. Methods The recombinant proteins SCF-Lα-GCSF and GCSF-Lα-SCF were purified in three steps using an ion-exchange and mixed-mode chromatography. The purity and quantity of the proteins after each stage of purification was assessed using RP-HPLC, SDS-PAGE, and the Bradford assays. Purified proteins were identified using high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) and the Western blot analyses. The molecular weight was determined by size exclusion HPLC (SE-HPLC). The activity of heterodimers was assessed using cell proliferation assays in vitro. The capacity of recombinant fusion proteins to stimulate the increase of the absolute neutrophil count in rats was determined in vivo. The binding kinetics of the proteins to immobilized G-CSF and SCF receptors was measured using total internal reflection ellipsometry and evaluated by a standard Langmuir kinetics model. Results The novel SCF-Lα-GCSF and GCSF-Lα-SCF proteins were synthesized in Escherichia coli. The purity of the heterodimers reached >90% as determined by RP-HPLC. The identity of the proteins was confirmed using the Western blot and HPLC/ESI-MS assays. An array of multimeric forms, non-covalently associated dimers or trimers were detected in the protein preparations by SE-HPLC. Each protein induced a dose-dependent proliferative response on the cell lines. At equimolar concentration, the heterodimers retain 70–140% of the SCF monomer activity (p ≤ 0.01) in promoting the M-07e cells proliferation. The G-CSF moiety in GCSF-Lα-SCF retained 15% (p ≤ 0.0001) and in SCF-Lα-GCSF retained 34% (p ≤ 0.01) of the monomeric G-CSF activity in stimulating the growth of G-NFS-60 cells. The obtained results were in good agreement with the binding data of each moiety in the fusion proteins to their respective receptors. The increase in the absolute neutrophil count in rats caused by the SCF-Lα-GCSF protein corresponded to the increase induced by a mixture of SCF and G-CSF.
Mickiene et al. (2020) Human granulocyte-colony stimulating factor (G-CSF)/stem cell factor (SCF) fusion proteins: design, characterization and activity. PeerJ 8:e9788 https://doi.org/10.7717/peerj.9788
Characterization of primary cilia features reveal cell-type specific variability in in vitro models of osteogenic and chondrogenic differentiation
Primary cilia are non-motile sensory antennae present on most vertebrate cell surfaces. They serve to transduce and integrate diverse external stimuli into functional cellular responses vital for development, differentiation and homeostasis. Ciliary characteristics, such as length, structure and frequency are often tailored to distinct differentiated cell states. Primary cilia are present on a variety of skeletal cell-types and facilitate the assimilation of sensory cues to direct skeletal development and repair. However, there is limited knowledge of ciliary variation in response to the activation of distinct differentiation cascades in different skeletal cell-types. C3H10T1/2, MC3T3-E1 and ATDC5 cells are mesenchymal stem cells, preosteoblast and prechondrocyte cell-lines, respectively. They are commonly employed in numerous in vitro studies, investigating the molecular mechanisms underlying osteoblast and chondrocyte differentiation, skeletal disease and repair. Here we sought to evaluate the primary cilia length and frequencies during osteogenic differentiation in C3H10T1/2 and MC3T3-E1 and chondrogenic differentiation in ATDC5 cells, over a period of 21 days. Our data inform on the presence of stable cilia to orchestrate signaling and dynamic alterations in their features during extended periods of differentiation. Taken together with existing literature these findings reflect the occurrence of not only lineage but cell-type specific variation in ciliary attributes during differentiation. These results extend our current knowledge, shining light on the variabilities in primary cilia features correlated with distinct differentiated cell phenotypes. It may have broader implications in studies using these cell-lines to explore cilia dependent cellular processes and treatment modalities for skeletal disorders centered on cilia modulation.
Upadhyai et al. (2020) Characterization of primary cilia features reveal cell-type specific variability in in vitro models of osteogenic and chondrogenic differentiation. PeerJ 8:e9799 https://doi.org/10.7717/peerj.9799
Current and future trends in socio-economic, demographic and governance factors affecting global primate conservation
Currently, ~65% of extant primate species (ca 512 species) distributed in 91 countries in the Neotropics, mainland Africa, Madagascar, South Asia and Southeast Asia are threatened with extinction and 75% have declining populations as a result of deforestation and habitat loss resulting from increasing global market demands, and land conversion for industrial agriculture, cattle production and natural resource extraction. Other pressures that negatively impact primates are unsustainable bushmeat hunting, the illegal trade of primates as pets and as body parts, expanding road networks in previously isolated areas, zoonotic disease transmission and climate change. Here we examine current and future trends in several socio-economic factors directly or indirectly affecting primates to further our understanding of the interdependent relationship between human well-being, sustainable development, and primate population persistence. We found that between 2001 and 2018 ca 191 Mha of tropical forest (30% canopy cover) were lost as a result of human activities in the five primate range regions. Forty-six percent of this loss was in the Neotropics (Mexico, Central and South America), 30% in Southeast Asia, 21% in mainland Africa, 2% in Madagascar and 1% in South Asia. Countries with the greatest losses (ca 57% of total tree cover loss) were Brazil, Indonesia, DRC, China, and Malaysia. Together these countries harbor almost 50% of all extant primate species. In 2018, the world human population was estimated at ca 8bn people, ca 60% of which were found in primate range countries. Projections to 2050 and to 2100 indicate continued rapid growth of the human populations in these five primate range regions, with Africa surpassing all the other regions and totaling ca 4bn people by the year 2100. Socioeconomic indicators show that, compared to developed nations, most primate range countries are characterized by high levels of poverty and income inequality, low human development, low food security, high levels of corruption and weak governance. Models of Shared Socioeconomic Pathway scenarios (SSPs) projected to 2050 and 2100 showed that whereas practices of increasing inequality (SSP4) or unconstrained growth in economic output and energy use (SSP5) are projected to have dire consequences for human well-being and primate survivorship, practices of sustainability-focused growth and equality (SSP1) are expected to have a positive effect on maintaining biodiversity, protecting environments, and improving the human condition. These results stress that improving the well-being, health, and security of the current and future human populations in primate range countries are of paramount importance if we are to move forward with effective policies to protect the world’s primate species and promote biodiversity conservation.
Estrada et al. (2020) Current and future trends in socio-economic, demographic and governance factors affecting global primate conservation. PeerJ 8:e9816 https://doi.org/10.7717/peerj.9816
Projection range of eDNA analysis in marshes: a suggestion from the Siberian salamander (Salamandrella keyserlingii) inhabiting the Kushiro marsh, Japan
Background Freshwater ecosystems are rapidly declining. The Siberian salamander (Salamandrella keyserlingii) which inhabits the Kushiro marsh in Hokkaido, Japan has lost some habitat due to human activity. There are many challenges associated with conventional monitoring methods, including cost, the need for specialist personnel, environmental impact, and ability to detect the presence of this species; thus, we investigated the feasibility of using environmental DNA (eDNA) analysis to detect its presence and identify its breeding grounds. Methods We performed tank experiments to confirm eDNA emission from egg sacs, larvae, and adult Siberian salamanders in the water. We also performed water sampling and visual observation of egg sacs in the Kushiro marsh during the end of the breeding season and the larval season. Results The tank experiments found eDNA emission from all growth stages. It also implied concentrated emissions just after spawning and after hatching, and limited emissions during the incubation phase in egg sacs. We also detected eDNA in the field, likely reflecting the distribution of egg sacs or larvae. Combining this data with visual observations, it was determined that the eDNA results from the field were best explained by the number of egg sacs within 7–10 m of the sampling point. Conclusions The results of this investigation show that the breeding sites and habitats of marshland species can successfully be monitored using eDNA analysis. They also suggest that the eDNA results from the marshes may reflect the biomass that is in close range to the sampling point. These results support the increased use of eDNA analysis in marshes and provide knowledge that could improve the interpretation of future results.
Takeshita et al. (2020) Projection range of eDNA analysis in marshes: a suggestion from the Siberian salamander (Salamandrella keyserlingii) inhabiting the Kushiro marsh, Japan. PeerJ 8:e9764 https://doi.org/10.7717/peerj.9764
Lake water volume fluctuations in response to climate change in Xinjiang, China from 2002 to 2018
Climate change has a global impact on the water cycle and its spatial patterns, and these impacts are more pronounced in eco-fragile regions. Arid regions are significantly affected by human activities like farming, and climate change, which influences lake water volumes, especially in different latitudes. This study integrates radar altimetry data from 2002 to 2018 with optical remote sensing images to analyze changes in the lake areas, levels, and volumes at different altitudes in Xinjiang, China. We analyzed changes in lake volumes in March, June, and October and studied their causes. The results showed large changes in the surface areas, levels, and volumes of lakes at different altitudes. During 2002–2010, the lakes in low- and medium-altitude areas were shrinking but lakes in high altitude areas were expanding. Monthly analysis revealed more diversified results: the lake water levels and volumes tended to decrease in March (−0.10 m/year, 37.55×108 m3) and increase in June (0.03 m/year, 3.48×108 m3) and October (0.04 m/year, 26.90×108 m3). The time series lake water volume data was reconstructed for 2011 to 2018 based on the empirical model and the total lake water volume showed a slightly increasing trend during this period (71.35×108 m3). We hypothesized that changes in lake water at high altitudes were influenced by temperature-induced glacial snow melt and lake water in low- to medium-altitude areas was most influenced by human activities like agricultural irrigation practices.
Wufu et al. (2020) Lake water volume fluctuations in response to climate change in Xinjiang, China from 2002 to 2018. PeerJ 8:e9683 https://doi.org/10.7717/peerj.9683
Improving the physical, mechanical and energetic properties of Quercus spp. wood pellets by adding pine sawdust
Background Biomass usage for energy purposes has emerged in response to global energy demands and environmental problems. The large amounts of by-products generated during logging are rarely utilized. In addition, some species (e.g., Quercus spp.) are considered less valuable and are left in the cutting areas. Production of pellets from this alternative source of biomass may be possible for power generation. Although the pellets may be of lower quality than other types of wood pellets, because of their physical and technological properties, the addition of different raw materials may improve the characteristics of the oak pellets. Methods Sawdust from the oak species Quercus sideroxyla, Q. rugosa, Q. laeta and Q. conzattii was mixed with sawdust from the pine Pinus durangensis in different ratios of oak to pine (100:0, 80:20, 60:40, 40:60 and 20:80). Physical and mechanical properties of the pellets were determined, and calorific value tests were carried out. For each variable, Kolmogorov–Smirnov normality and Kruskal–Wallis tests were performed and Pearson’s correlation coefficients were determined (considering a significance level of p < 0.05). Results The moisture content and fixed carbon content differed significantly (p < 0.05) between the groups of pellets (i.e., pellets made with different sawdust mixtures). The moisture content of all pellets was less than 10%. However, volatile matter and ash content did not differ significantly between groups (p ≥ 0.05). The ash content was less than 0.7% in all mixtures. The addition of P. durangensis sawdust to the mixtures improved the bulk density of the pellets by 18%. Significant differences (p < 0.05) in particle density were observed between species, mixtures and for the species × mixture interaction. The particle density was highest in the 80:20 and 60:40 mixtures, with values ranging from 1,245 to 1,349 kg m−3. Bulk density and particle density of the pellets were positively correlated with the amount of P. durangensis sawdust included. The mechanical hardness and impact resistance index (IRI) differed significantly (p < 0.05) between groups. The addition of pine sawdust decreased the mechanical hardness of the pellets, up to 24%. The IRI was highest (138) in the Q. sideroxyla pellets (100:0). The mechanical hardness and IRI of the pellets were negatively correlated with the amount of P. durangensis sawdust added. The bulk density of the pellets was negatively correlated with mechanical hardness and IRI. The calorific value of mixtures and the species × mixture interaction differed significantly between groups. Finally, the mean calorific value was highest (19.8 MJ kg−1) in the 20:80 mixture. The calorific value was positively related to the addition of P. durangensis sawdust.
Núñez-Retana et al. (2020) Improving the physical, mechanical and energetic properties of Quercus spp. wood pellets by adding pine sawdust. PeerJ 8:e9766 https://doi.org/10.7717/peerj.9766