Growth-promoting characteristics of potential nitrogen-fixing bacteria in the root of an invasive plant Ageratina adenophora
Root endophytic nitrogen-fixing bacteria (reNFB) have been proposed as important contributors to the invasiveness of exotic legumes; however, the reNFB of invasive nonlegumes has received less attention. In particular, the growth-promoting effect of reNFB on invasive plants remains unknown. In this study, 131 strains of potential nitrogen-fixing bacteria were isolated and purified from the roots of the invasive plant, Ageratina adenophora, in Southwest China. Phylogenetically, these reNFB were categorized into three phyla at 97% sequence identity that included Proteobacteria (92.4%), Actinobacteria (4.6%), and Firmicutes (3.1%). The dominant isolates ranked by number were Pseudomonas (80 isolates, 61.1%), Rhizobium (12 isolates, 9.2%), and Duganella (11 isolates, 8.4%). The community composition and diversity of A. adenophora reNFB were markedly different across study regions. The capacity of these reNFB to accumulate indolyl-3-acetic acid (IAA), solubilize phosphate, and produce siderophores was determined. All 131 isolates of reNFB accumulated IAA, 67 isolates solubilized phosphate, and 108 isolates produced siderophores. Among the three dominant genera of reNFB, Pseudomonas had the highest phosphorus solubilization and siderophore production, while the accumulation of IAA in the genus Duganella was the lowest. Interestingly, the calculated reNFB Shannon diversity index of each A. adenophora individual was negatively correlated with the capacity of reNFB to produce growth-promoting products. Six randomly selected isolates from three dominant genera were further used to conduct inoculation experiments, and all isolates showed significant positive growth-promoting effects on A. adenophora seedlings. The contribution of reNFB to the root biomass was higher than that to the shoot biomass. Our results suggest that reNFB, similar to soil or nodular nitrogen-fixing bacteria, can potentially promote plant growth and may play an important role in the invasion of nonleguminous plants. More detailed studies on the correlation between reNFB and invasive plants are necessary.
Fang et al. (2019) Growth-promoting characteristics of potential nitrogen-fixing bacteria in the root of an invasive plant Ageratina adenophora. PeerJ 7:e7099 https://doi.org/10.7717/peerj.7099
Engagement in physical activity, suicidal thoughts and suicide attempts among older people in five developing countries
Background Suicide causes rising economic costs and public health risks for communities in the worldwide. Physical activity (PA) is considered a potentially feasible approach to reduce risk of suicide with low cost and high accessibility, and therefore attracting increasing attention. However, current literature on the association between PA and suicidal behavior amongst elderly people in low- and middle-income countries (LMICs) are scarce. Therefore, in this study we aimed to examine the relationship between suicidal thoughts (ST) and suicidal attempts (SA) with PA among elderly people in five LMICs. Methods Cross-sectional data were collected from WHO’s Study of Global Ageing and Adult Health (SAGE) with 2,861 participants aged 50 years or above. Variables included: self-reported occurrence of ST and SA during past 12 months and four types of PA (vigorous physical activity (VPA), moderate physical activity (MPA), walking/bike riding, moderate leisure time physical activity (MLPA)). Results The overall prevalence of taking >75 min of VPA/week, >150 min/week, MLPA and walking/bike riding were, respectively, 85.4% (95% CI [81.3–88.7]), 61.6% (95% CI [52.9–69.6]), 9.6% (95% CI [7.2–12.6]) and 75.1% (95% CI [68.7–80.6]). Respectively, 31.0% (95% CI [24.3–38.7]) and 5.5% (95% CI [3.9–7.5]) of the respondents reported having morbid thoughts and SA during last 12 months. In adjusted multivariable regression analysis, not engaging in PA revealed positive association with higher odds of having morbid thoughts and SA, however, with varying degrees for different types of PA among men and women and across countries. The adjusted odds ratio among elderly who encountered ST increased significantly with PA levels (1.265 in male and 1.509 in female with VPA, 1.292 in male and 1.449 in female with MPA, 1.669 in female with LMPA and 3.039 in women with walk/bike); similarly, with SA (1.526, 1.532, 1.474 and 1.392 in women with VPA, MPA, LMPA and Walk/bike, respectively). The degree of adjusted odds ratio varied between genders and among countries. Conclusion Although the data were cross-sectional, and no linear dose-response relationship was observed between PA and morbid thought and suicide ideation, the findings provide important indications of potential harmful effects of no/inadequate PA on psychological morbidities among older individuals. Promoting adequate PA among older individuals through community-based suicide prevention programs can potentially contribute to reduction in the burden of PA in LMICs.
Ghose et al. (2019) Engagement in physical activity, suicidal thoughts and suicide attempts among older people in five developing countries. PeerJ 7:e7108 https://doi.org/10.7717/peerj.7108
Spotting the “small eyes”: using photo-ID methodology to study a wild population of smalleye stingrays (Megatrygon microps) in southern Mozambique
Background The smalleye stingray (Megatrygon microps) is a large and rare dasyatid ray, patchily distributed across the Indo-West Pacific. Free-swimming individuals have regularly been recorded in Southern Mozambican coastal waters utilizing different inshore environments. Distinctive features of the species include latitudinal rows of white spots on the dorsal surface of their pectoral disc. Methods This study aimed to determine if the natural spot patterns on M. microps are sufficiently unique and stable to use in photo-identification studies of wild populations. Research dive logs were combined with opportunistic photographs from local dive centers and recreational divers to create a photographic database from the Inhambane Province coastline. Results Seventy different individuals were identified over a 15-year period, all exhibiting uniquely identifiable patterns. Stingrays were easily identifiable over a period of six years with multiple re-sightings of the same individuals recorded. Analysis of encounters across the Inhambane coastline revealed that individual rays regularly use inshore reefs along a 350 km stretch of coastline. Fifteen stingrays were re-sighted during the study period, including one showing a 400 km return movement between Tofo Beach and the Bazaruto Archipelago, which is the longest distance traveled by a dasyatid ray on record. Several presumably pregnant females have also been recorded in the Bazaruto Archipelago National Park.
Boggio-Pasqua et al. (2019) Spotting the “small eyes”: using photo-ID methodology to study a wild population of smalleye stingrays (Megatrygon microps) in southern Mozambique. PeerJ 7:e7110 https://doi.org/10.7717/peerj.7110
A new species of Micryletta frog (Microhylidae) from Northeast India
We describe a new species of frog in the microhylid genus Micryletta Dubois, 1987 from Northeast India based on molecular and morphological evidence. The new species, formally described as Micryletta aishani sp. nov., is phenotypically distinct from other congeners by a suite of morphological characters such as brown to reddish-brown dorsum; dorsal skin shagreened with minute spinules; snout shape nearly truncate in dorsal and ventral view; a prominent dark streak extending from tip of the snout up to the lower abdomen; ash-grey mottling along the margins of upper and lower lip extending up to the flanks, limb margins and dorsal surfaces of hand and foot; tibiotarsal articulation reaching up to the level of armpits; absence of outer metatarsal tubercles; and absence of webbing between toes. Phylogenetic relationships within the genus are inferred based on mitochondrial data and the new taxon is found to differ from all the recognised Micryletta species by 3.5–5.9% divergence in the mitochondrial 16S rRNA. The new species was found in the states of Assam, Manipur, and Tripura, from low to moderate elevation (30–800 m asl) regions lying south of River Brahmaputra and encompassing the Indo-Burma Biodiversity Hotspot. The discovery validates the presence of genus Micryletta in Northeast India based on genetic evidence, consequently confirming the extension of its geographical range, westwards from Southeast Asia up to Northeast India. Further, for nomenclatural stability of two previously known species, Microhyla inornata (= Micryletta inornata) and Microhyla steinegeri (= Micryletta steinegeri), lectotypes are designated along with detailed descriptions.
Das et al. (2019) A new species of Micryletta frog (Microhylidae) from Northeast India. PeerJ 7:e7012 https://doi.org/10.7717/peerj.7012
Conservation and diversity in expression of candidate genes regulating socially-induced female-male sex change in wrasses
Fishes exhibit remarkably diverse, and plastic, patterns of sexual development, most striking of which is sequential hermaphroditism, where individuals readily reverse sex in adulthood. How this stunning example of phenotypic plasticity is controlled at a genetic level remains poorly understood. Several genes have been implicated in regulating sex change, yet the degree to which a conserved genetic machinery orchestrates this process has not yet been addressed. Using captive and in-the-field social manipulations to initiate sex change, combined with a comparative qPCR approach, we compared expression patterns of four candidate regulatory genes among three species of wrasses (Labridae)—a large and diverse teleost family where female-to-male sex change is pervasive, socially-cued, and likely ancestral. Expression in brain and gonadal tissues were compared among the iconic tropical bluehead wrasse (Thalassoma bifasciatum) and the temperate spotty (Notolabrus celidotus) and kyusen (Parajulus poecilepterus) wrasses. In all three species, gonadal sex change was preceded by downregulation of cyp19a1a (encoding gonadal aromatase that converts androgens to oestrogens) and accompanied by upregulation of amh (encoding anti-müllerian hormone that primarily regulates male germ cell development), and these genes may act concurrently to orchestrate ovary-testis transformation. In the brain, our data argue against a role for brain aromatase (cyp19a1b) in initiating behavioural sex change, as its expression trailed behavioural changes. However, we find that isotocin (it, that regulates teleost socio-sexual behaviours) expression correlated with dominant male-specific behaviours in the bluehead wrasse, suggesting it upregulation mediates the rapid behavioural sex change characteristic of blueheads and other tropical wrasses. However, it expression was not sex-biased in temperate spotty and kyusen wrasses, where sex change is more protracted and social groups may be less tightly-structured. Together, these findings suggest that while key components of the molecular machinery controlling gonadal sex change are phylogenetically conserved among wrasses, neural pathways governing behavioural sex change may be more variable.
Thomas et al. (2019) Conservation and diversity in expression of candidate genes regulating socially-induced female-male sex change in wrasses. PeerJ 7:e7032 https://doi.org/10.7717/peerj.7032
The role of acetyl-coA carboxylase2 in head and neck squamous cell carcinoma
Background Acetyl-CoA carboxylase (ACC) plays an important role in the metabolism of various cancer cells, but its role in head and neck squamous cell carcinoma (HNSCC) is uncertain. Therefore, in the present study, we explored the role of ACC2 in HNSCC. Methods Western blot and immunohistochemistry assays were used to determine ACC2 protein expression levels in laryngocarcinoma and adjacent normal tissues derived from patients with laryngocarcinoma. ACC2 expression was knocked down in the hypopharyngeal cancer cell line FaDu to determine its effect on apoptosis. Lipid oil red staining was used to test the change of intracellular lipid. Results The results showed that the ACC2 protein was highly expressed in laryngocarcinoma and that the ACC2 expression level was positively associated with the clinical cancer stage and negatively associated with the degree of laryngocarcinoma cell differentiation. Kaplan–Meier analyses indicated that compared with patients having low levels of ACC2, those with high ACC2 levels had a decreased 5-year survival rate. The results of western blot and terminal deoxynucleotidyl transferase dUTP nick-end labeling assays showed that knockdown of ACC2 accelerated apoptosis in FaDu cells. Furthermore, knockdown of ACC2 significantly reduced the intracellular lipid levels in FaDu cells. Conclusion These findings suggest that ACC2 may be an important prognostic marker for patients with HNSCC and that ACC2 may be a potential target in the treatment of HNSCC.
Li et al. (2019) The role of acetyl-coA carboxylase2 in head and neck squamous cell carcinoma. PeerJ 7:e7037 https://doi.org/10.7717/peerj.7037
Elaborated pollen packaging and dispensing mechanism induced by petal architecture from a Papaveraceae species
Secondary pollen presentation (SPP) is a reproductive strategy that enhances the efficiency of pollen transfer, which has been explored for more than 200 years, resulting in 10 identified types of SPP. The ephemeral plant Hypecoum erectum L. (Papaveraceae) has an elaborate petal structure. The middle lobe is a key functional organ in SPP. To explore the importance of the middle lobe structure, we measured the flowering process, the curling movement and growth of the middle lobe, pollination characteristics, pollination efficiency, and the mating system in H. erectum in the field. The yellow middle lobe structure had an important role in attracting pollinators. The middle lobes on the inner petals function as a redundant cucullate structure and wrapped about 84% of the total pollen grains as soon as the anthers dehisced. These then grew upward and gradually presented pollen to pollinators via the roll out of the middle lobes. One bee species, Colletes vestitus from Colletidae, was the only effective pollinator of H. erectum. The SPP mechanism increased the efficiency of pollen transfer by C. vestitus. The middle lobes, which wrapped pollen and grew upward, contacted the stigma and provided an advantage for self-pollination and outcrossing by growing upward higher than the corolla. Hypecoum erectum L. has a mixed mating system with selfing and outcrossing. Thus, the SPP mechanism plays a key role during the pollination process and is necessary for improving pollination efficiency and promoting reproductive success.
Yang et al. (2019) Elaborated pollen packaging and dispensing mechanism induced by petal architecture from a Papaveraceae species. PeerJ 7:e7066 https://doi.org/10.7717/peerj.7066
PGM5: a novel diagnostic and prognostic biomarker for liver cancer
Background Liver cancer is a common malignancy and a significant public health problem worldwide, but diagnosis and prognostic evaluation remain challenging for clinicians. Metabolic reprogramming is a hallmark of cancer, and we therefore examined the diagnostic and prognostic value of a metabolic enzyme, phosphoglucomutase-like protein 5 (PGM5), in liver cancer. Methods All data were from The Cancer Genome Atlas database. R and related statistical packages were used for data analysis. Hepatic PGM5 expression was determined in different groups, and the chi-squared test and Fisher’s exact test were used to determine the significance of differences. The pROC package was used to determine receiver operating characteristic (ROC) curves, the survival package was used to for survival analysis and development of a Cox multivariable model, and the ggplot2 package was used for data visualization. Results PGM5 expression was significantly lower in cancerous than adjacent normal liver tissues, and had modest diagnostic value based on ROC analysis and calculations of area under the curve (AUC). Hepatic PGM5 expression had positive associations with male sex and survival, but negative associations with advanced histologic type, advanced histologic grade, advanced stage, and advanced T classification. Patents with low PGM5 levels had poorer overall survival and relapse-free survival. PGM5 was independently associated with patient prognosis. Conclusion PGM5 has potential use as a diagnostic and prognostic biomarker for liver cancer.
Jiao et al. (2019) PGM5: a novel diagnostic and prognostic biomarker for liver cancer. PeerJ 7:e7070 https://doi.org/10.7717/peerj.7070
The role of serum and urinary biomarkers in the diagnosis of early diabetic nephropathy in patients with type 2 diabetes
Background Previous studies have shown that a variety of biomarkers are closely related to the occurrence and development of early-stage diabetic nephropathy (DN) in patients. The aim of this study was to evaluate the role of multiple sera and urinary biomarkers in the diagnosis of early-stage DN in patients with type 2 diabetes. Methods We enrolled 287 patients with type 2 diabetes, who were classified into normoalbuminuria (n = 144), microalbuminuria (n = 94), or macroalbuminuria (n = 49) groups based on their urine albumin to creatinine ratios (UACR), along with 42 healthy controls. We assessed 13 biomarkers, including transferrin (Tf), immunoglobulin G (IgG), podocalyxin, neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl-beta-glucosaminidase, α-1-microglobulin, 8-hydroxy-deoxyguanosine, tumor necrosis factor-alpha (TNF-α), and interleukin-18 in urine samples, along with cystatin C, total bilirubin, and uric acid in sera samples, to evaluate their diagnostic roles. From the measurements, the blood neutrophil to lymphocyte ratio was also calculated. Results Urinary Tf, IgG, NGAL, and TNF-α were significantly related to the UACR. We calculated the area under the receiver operating characteristic curves (area under the curve) and found that urinary IgG (0.894), NGAL (0.875), Tf (0.861), TNF-α (0.763), and the combination of urinary Tf + IgG + TNF-α + NGAL (0.922) showed good diagnostic value for early-stage DN. Conclusions Urinary Tf, IgG, NGAL, TNF-α, and the combination of all four biomarkers demonstrated excellent diagnostic value for early-stage DN in patients with type 2 diabetes.
Zhang et al. (2019) The role of serum and urinary biomarkers in the diagnosis of early diabetic nephropathy in patients with type 2 diabetes. PeerJ 7:e7079 https://doi.org/10.7717/peerj.7079
Hydroclimatic variations reveal differences in carbon capture in two sympatric conifers in northern Mexico
Background Forest ecosystems are considered among the largest terrestrial carbon sinks. The dynamics of forest carbon depend on where the carbon is stored and its responses to environmental factors, as well as the physiology of the trees. Thus, threatened forest regions with high biodiversity have great scientific importance, such as the Sierra Madre Occidental in Mexico. A comparative analysis of tree species can expand the knowledge of the carbon cycle dynamics and ecological processes in this region. Here, we examined the growth, wood density, and carbon accumulation of two threatened species (Pseudotsuga menziesii and Cupressus lusitanica) to evaluate their hydroclimatic responsiveness. Methods The temporal variations in the carbon accumulation patterns of two co-occurring species (P. menziesii and C. lusitanica) and their sensitivity to the local climate were studied using dendroecological techniques, X-ray densitometry, and allometric equations. Results The results show that the annual carbon accumulation in C. lusitanica is positively associated with the temperature during the current fall, while the carbon accumulation in P. menziesii is correlated with the rainfall during the winter of the previous year. The climatic responses are associated with the intra-annual variations of wood density and ring widths for each species. The ring width was strongly correlated with carbon accumulation in C. lusitanica, while the mean wood density was linked to carbon accumulation in P. menziesii. Discussion This study has implications for the carbon accumulation rates of both species, revealing differences in the carbon capture patterns in response to climatic variations. Although the species coexist, there are variation in the hydroclimatic sensitivity of the annual carbon sequestered by trunks of trees, which would be associated with tree-ring width and/or wood density, i.e., directly by anatomical features. The results are relevant to analyze the response to the variability of climatic conditions expected in the near future of the tree communities of Sierra Madre Occidental. Therefore, this study provides a basis for modeling the long-term carbon budget projections in terrestrial ecosystems in northern Mexico.
González-Cásares et al. (2019) Hydroclimatic variations reveal differences in carbon capture in two sympatric conifers in northern Mexico. PeerJ 7:e7085 https://doi.org/10.7717/peerj.7085