Physiological responses of hydroponically-grown Japanese mint under nutrient deficiency
This research aims to determine growth and deficiency patterns as well as antioxidative potentials of Japanese mint (Mentha arvensis) hydroponically grown under limited macronutrients and micronutrients. The experiment was conducted for 60 days after transplanting in an evaporative greenhouse (avg temp = 28–30 °C, 60–65 %RH), using deep water culture technique. Plants were grown in nutrient solution consisting of complete Hoagland’s solution (CTRL), and nutrient solutions lacking one of the following macronutrients and micronutrients: nitrogen (-N), phosphorus (-P), potassium (-K), iron (-Fe), manganese (-Mn), and copper (-Cu). The deficiency symptoms, growth patterns, and stress response mechanism were followed. All treatments except for the CTRL induced deficiency symptoms and physiological changes. Macronutrient deprivation reduced growth determined by the morphological parameters while micronutrient omission had no effect except for no iron treatment. The result showed that potassium and iron deficiencies had foremost adversely effect on growth of Japanese mint. Under nutrient stress conditions, plant only gave antioxidative responses to phosphorus and potassium deficiencies. However, the negative plant-stress relationship was found for no iron treatment indicating the detoxification mode of plant for lacking of micronutrient.
Janpen et al. (2019) Physiological responses of hydroponically-grown Japanese mint under nutrient deficiency. PeerJ 7:e7751 https://doi.org/10.7717/peerj.7751
Simulated manned Mars exploration: effects of dietary and diurnal cycle variations on the gut microbiome of crew members in a controlled ecological life support system
Background Changes in gut microbiome are closely related to dietary and environment variations, and diurnal circle interventions impact on human metabolism and the microbiome. Changes in human gut microbiome and serum biochemical parameters during long-term isolation in a controlled ecological life support system (CELSS) are of great significance for maintaining the health of crewmembers. The Green Star 180 project performed an integrated study involving a four-person, 180-day duration assessment in a CELSS, during which variations in gut microbiome and the concentration of serum 25-hydroxyvitamin D, α-tocopherol, retinol and folic acid from the crewmembers were determined. Results Energy intake and body mass index decreased during the experiment. A trade-off between Firmicutes and Bacteroidetes during the study period was observed. Dynamic variations in the two dominant genus Bacteroides and Prevotella indicated a variation of enterotypes. Both the evenness and richness of the fecal microbiome decreased during the isolation in the CELSS. Transition of diurnal circle from Earth to Mars increased the abundance of Fusobacteria phylum and decreased alpha diversity of the fecal microbiome. The levels of serum 25-hydroxyvitamin D in the CELSS were significantly lower than those outside the CELSS. Conclusions The unique isolation process in the CELSS led to a loss of alpha diversity and a transition of enterotypes between Bacteroides and Prevotella. Attention should therefore be paid to the transition of the diurnal circle and its effects on the gut microbiome during manned Mars explorations. In particular, serum 25-hydroxyvitamin D levels require monitoring under artificial light environments and during long-term space flight. Large-scale studies are required to further consolidate our findings.
Dong et al. (2019) Simulated manned Mars exploration: effects of dietary and diurnal cycle variations on the gut microbiome of crew members in a controlled ecological life support system. PeerJ 7:e7762 https://doi.org/10.7717/peerj.7762
The relationships between bilingual learning, willingness to study abroad and convergent creativity
Convergent creativity is a form of creative thinking that uses existing knowledge or traditional methods to analyze available information and generate an appropriate solution. The differences in the performance of participants in convergent creativity caused by bilingual learning is a popular research area in creativity. A final sample of 68 participants was asked to complete the remote associates test (RAT). The results indicate that a moderate positive correlation exists between bilingual learning and convergent creativity. Students who want to study abroad perform better on the RAT than those who do not, and this effect is mediated by second language proficiency. These findings suggest that improving students’ English proficiency and increasing their opportunities to study abroad may be effective ways to promoting convergent creativity.
Zhao et al. (2019) The relationships between bilingual learning, willingness to study abroad and convergent creativity. PeerJ 7:e7776 https://doi.org/10.7717/peerj.7776
Transcriptome association studies of neuropsychiatric traits in African Americans implicate PRMT7 in schizophrenia
In the past 15 years, genome-wide association studies (GWAS) have provided novel insight into the genetic architecture of various complex traits; however, this insight has been primarily focused on populations of European descent. This emphasis on European populations has led to individuals of recent African descent being grossly underrepresented in the study of genetics. With African Americans making up less than 2% of participants in neuropsychiatric GWAS, this discrepancy is magnified in diseases such as schizophrenia and bipolar disorder. In this study, we performed GWAS and the gene-based association method PrediXcan for schizophrenia (n = 2,256) and bipolar disorder (n = 1,019) in African American cohorts. In our PrediXcan analyses, we identified PRMT7 (P = 5.5 × 10−6, local false sign rate = 0.12) as significantly associated with schizophrenia following an adaptive shrinkage multiple testing adjustment. This association with schizophrenia was confirmed in the much larger, predominantly European, Psychiatric Genomics Consortium. In addition to the PRMT7 association with schizophrenia, we identified rs10168049 (P = 1.0 × 10−6) as a potential candidate locus for bipolar disorder with highly divergent allele frequencies across populations, highlighting the need for diversity in genetic studies.
Fiorica et al. (2019) Transcriptome association studies of neuropsychiatric traits in African Americans implicate PRMT7 in schizophrenia. PeerJ 7:e7778 https://doi.org/10.7717/peerj.7778
Comprehensive evaluation of fluroxypyr herbicide on physiological parameters of spring hybrid millet
Foxtail millet (Setaria italic L.) is an important food and fodder crop that is cultivated worldwide. Quantifying the effects of herbicides on foxtail millet is critical for safe herbicide application. In this study, we analyzed the effects of different fluroxypyr dosages on the growth parameters and physiological parametric of foxtail millet, that is, peroxidation characteristics, photosynthetic characteristics, and endogenous hormone production, by using multivariate statistical analysis. Indicators were screened via Fisher discriminant analysis, and the growth parameters, peroxidation characteristics, photosynthesis characteristics and endogenous hormones of foxtail millet at different fluroxypyr dosages were comprehensively evaluated by principal component analysis. On the basis of the results of principal component analysis, the cumulative contribution rate of the first two principal component factors was 93.72%. The first principal component, which explained 59.23% of total variance, was selected to represent the photosynthetic characteristics and endogenous hormones of foxtail millet. The second principal component, which explained 34.49% of total variance, represented the growth parameters of foxtail millet. According to the principal component analysis, the indexes were simplified into comprehensive index Z, and the mathematical model of comprehensive index Z was set as F = 0.592Z1 + 0.345Z2. The results showed that the comprehensive evaluation score of fluroxypyr at moderate concentrations was higher than at high concentrations. Consequently, one L (active ingredient, ai) ha−1 fluroxypyr exerted minimal effects on growth parameters, oxidase activity, photosynthetic activity, and endogenous hormones, and had highest value of comprehensive evaluation, which had efficient and safe benefits in foxtail millet field.
Guo et al. (2019) Comprehensive evaluation of fluroxypyr herbicide on physiological parameters of spring hybrid millet. PeerJ 7:e7794 https://doi.org/10.7717/peerj.7794
The rediscovery of the rare Vietnamese endemic Eriophorum scabriculme redefines generic limits in the Scirpo-Caricoid Clade (Cyperaceae)
For those familiar with boreal bogs and wet tundra, species of Eriophorum (“the cotton grasses”) will undoubtedly represent some of the most striking and memorable taxa they have encountered. This small genus of 20 Holarctic sedge species (Cyperaceae) is remarkable because its inflorescences produce large, brilliantly white to rusty-red cottony masses when its flowers develop a perianth of highly elongated bristles after anthesis. In this study, we document the rediscovery of Eriophorum scabriculme, a narrow Vietnamese endemic known from only two collections made approximately 7 km apart near Sa Pa in Lào Cai Province over 75 years ago. Using plastid DNA sequences (matK, ndhF), embryology, and morphology, we test whether E. scabriculme is aligned within the Scirpo-Caricoid Clade (genus Khaosokia and tribes Cariceae, Dulichieae, Scirpeae, and Sumatroscirpeae) or the Ficinia Clade (Cypereae), and we determine whether its unique character combinations (≥10 elongated bristles, reduced sheathing basal leaves, 1–4 spikelets) could be evidence for a new genus or simply mark it as an unusual species within currently recognised genera. In addition, we document the discovery of seven new populations, and we extend its range westward to Lai Châu Province and southward in Lào Cai Province by more than 47 km. Our results demonstrate that Eriophorum scabriculme is best treated in the genus Trichophorum, thus re-circumscribing both genera and their limits with Scirpus s.str. In addition, we emend the description of Trichophorum scabriculme (Beetle) J.R.Starr, Lév.-Bourret & B.A. Ford, provide the first pictures and accurate illustration of the species, and assess its conservation status in Vietnam (VU, Vulnerable). Our study corroborates the fact that in such a diverse and taxonomically difficult family like the sedges, conspicuous characters like highly elongated bristles may be useful for dividing diversity, but they are no guarantee that the groups they mark are natural.
Starr et al. (2019) The rediscovery of the rare Vietnamese endemic Eriophorum scabriculme redefines generic limits in the Scirpo-Caricoid Clade (Cyperaceae). PeerJ 7:e7538 https://doi.org/10.7717/peerj.7538
Cellular accumulation and cytotoxic effects of zinc oxide nanoparticles in microalga Haematococcus pluvialis
Background Zinc oxide nanoparticles (ZnO NPs) are widely used in household and cosmetic products which imply an increased releasing of these particles into the environment, especially aquatic ecosystems, resulting in the need of assessing the potential toxic effects of ZnO NPS on the aquatic organisms, particularly on microalgae which form the base for food chain of aquatic biota. The present study has investigated the dose- and time-dependent cellular accumulation and the corresponding cytotoxic effects of increasing concentrations of ZnO NPs from 10–200 μg/mL on microalga Haematococcus pluvialis at an interval of 24 h for 96 h. Methods The scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) was used to qualitatively detect the cellular accumulation of ZnO NPs in algal cells, while inductively coupled plasma optical emission spectrometry (ICP OES) was performed to quantify the cell associated-zinc in algal cells. The percentage of cell death, reduction in algal biomass, and loss in photosynthetic pigments were measured to investigate the cytotoxic effects of ZnO NPs on H. pluvialis. Extracellular and intracellular changes in algal cells resulted from the treatment of ZnO NPs were demonstrated through optical, scanning, and transmission electron microscopic studies. Results SEM-EDX spectrum evidenced the accumulation of ZnO NPs in algal biomass and ICP OES results reported a significant (p < 0.05) dose- and time-dependent accumulation of zinc in algal cells from 24 h for all the tested concentrations of ZnO NPs (10–200 μg/mL). Further, the study showed a significant (p < 0.05) dose- and time-dependent growth inhibition of H. pluvialis from 72 h at 10–200 μg/mL of ZnO NPs. The morphological examinations revealed substantial surface and intracellular damages in algal cells due to the treatment of ZnO NPs. Discussion The present study reported the significant cellular accumulation of ZnO NPs in algal cells and the corresponding cytotoxic effects of ZnO NPs on H. pluvialis through the considerable reduction in algal cell viability, biomass, and photosynthetic pigments together with surface and intracellular damages.
Djearamane et al. (2019) Cellular accumulation and cytotoxic effects of zinc oxide nanoparticles in microalga Haematococcus pluvialis. PeerJ 7:e7582 https://doi.org/10.7717/peerj.7582
The effects of growth rate and biomechanical loading on bone laminarity within the emu skeleton
The orientation of vascular canals in primary bone may reflect differences in growth rate and/or adaptation to biomechanical loads. Previous studies link specific canal orientations to bone growth rates, but results between different taxa are contradictory. Circumferential vascular canals (forming laminar bone) have been hypothesized to reflect either (or both) rapid growth rate or locomotion-induced torsional loading. Previous work on the hindlimb biomechanics in the emu shows that the femur and tibiotarsus experience large shear strains, likely resulting from torsional loads that increase through ontogeny. Here, we test how growth rate and biomechanical loading affect bone laminarity in wing and hindlimb elements from growing emu (2–60 wks). If laminar bone is an adaptation to torsion-induced shear strains, it should increase from juveniles to adults. Alternatively, if bone laminarity reflects rapid growth, as has been shown previously in emu, it should be abundant in fast-growing juveniles and decrease with age. Transverse mid-shaft histological sections from the limb bones (femur, tibiotarsus, humerus, ulna, and radius) were prepared and imaged. Growth rates were measured using fluorescent bone labels. Vascular canal orientation was quantified using laminarity index (proportion of circumferential canals). Principal components analysis was performed to convert highly correlated variables (i.e., mass, age, growth rate, and shear strain) into principal components. Random-intercept beta regression modeling determined which principal components best explained laminarity. The fastest growth rates were found in young individuals for all five skeletal elements. Maximum growth rate did not coincide with peak laminarity. Instead, in the femur and tibiotarsus, elevated laminarity is strongly correlated with adult features such as large size, old age, and modest growth rate. This result is contrary to predictions made based on a previous study of emu but is consistent with results observed in some other avian species (penguin, chicken). Shear strain in the caudal octant of the femur and tibiotarsus is positively correlated with laminarity but has a weaker effect on laminarity relative to mass, age, and growth rate. Laminarity in the wing elements is variable and does not correlate with ontogenetic factors (including mass, age, and growth rate). Its presence may relate to relaxed developmental canalization or a retained ancestral feature. In conclusion, ontogeny (including growth rate) is the dominant influence on vascular canal orientation at least in the hindlimb of the emu.
Kuehn et al. (2019) The effects of growth rate and biomechanical loading on bone laminarity within the emu skeleton. PeerJ 7:e7616 https://doi.org/10.7717/peerj.7616
Bar-HRM: a reliable and fast method for species identification of ginseng (Panax ginseng, Panax notoginseng, Talinum paniculatum and Phytolacca Americana)
Background Korean ginseng has long been famous and is one of the most well known forms of ginseng. The root of plants in the genus Panax is commonly recognized as ginseng. Different Panax species of ginseng root have been used as treatments. Although many other herbs are called ginseng, they do not contain the active compounds of ginsenosides. In Thailand, we have Thai ginseng which is of course not one of Panax species. Thai ginseng is the root from Talinum paniculatum and, due to its morphological root similarity, it is almost impossible to differentiate between them. Also, another plant species, Phytollacca americana, has significantly similar root morphology to real ginseng but its seeds and root are poisonous. Misunderstanding what true ginseng is compared to others could endanger lives and cause financial loss by buying inferior products. Methods DNA barcoding combination with High Resolution Melting (called Bar-HRM) was used for species discrimination of the Panax ginseng and others. Five regions included ITS2, matK, psbA-trnH and rbcL were evaluated in the analyses. Results The ITS2 region was found to be the most suitable primers for the analysis. The melting profile from the HRM analyses using the chosen ITS2 primers showed that Korean ginseng (Panax ginseng) could be discriminated from other Penax species. Also, other ginseng species with morphological similarity could be easily distinguished from the true ginseng. The developed Bar-HRM method poses a great potential in ginseng species discrimination and thus could be also useful in ginseng authentication.
Osathanunkul et al. (2019) Bar-HRM: a reliable and fast method for species identification of ginseng (Panax ginseng, Panax notoginseng, Talinum paniculatum and Phytolacca Americana). PeerJ 7:e7660 https://doi.org/10.7717/peerj.7660
Effect of reduced pH on physiology and shell integrity of juvenile Haliotis iris (pāua) from New Zealand
The New Zealand pāua or black footed abalone, Haliotis iris, is one of many mollusc species at potential risk from ocean acidification and warming. To investigate possible impacts, juvenile pāua (~24 mm shell length) were grown for 4 months in seawater pH/pCO2 conditions projected for 2100. End of century seawater projections (pHT 7.66/pCO2 ~1,000 μatm) were contrasted with local ambient conditions (pHT 8.00/pCO2 ~400 μatm) at two typical temperatures (13 and 15 °C). We used a combination of methods (morphometric, scanning electron microscopy, X-ray diffraction) to investigate effects on juvenile survival and growth, as well as shell mineralogy and integrity. Lowered pH did not affect survival, growth rate or condition, but animals grew significantly faster at the higher temperature. Juvenile pāua were able to biomineralise their inner nacreous aragonite layer and their outer prismatic calcite layer under end-of-century pH conditions, at both temperatures, and carbonate composition was not affected. There was some thickening of the nacre layer in the newly deposited shell with reduced pH and also at the higher temperature. Most obvious was post-depositional alteration of the shell under lowered pH: the prismatic calcite layer was thinner, and there was greater etching of the external shell surface; this dissolution was greater at the higher temperature. These results demonstrate the importance of even a small (2 °C) difference in temperature on growth and shell characteristics, and on modifying the effects at lowered pH. Projected CO2-related changes may affect shell quality of this iconic New Zealand mollusc through etching (dissolution) and thinning, with potential implications for resilience to physical stresses such as predation and wave action.
Cummings et al. (2019) Effect of reduced pH on physiology and shell integrity of juvenile Haliotis iris (pāua) from New Zealand. PeerJ 7:e7670 https://doi.org/10.7717/peerj.7670