PeerJ
type: channel
link: https://peerj.com/articles/
description: Articles published in PeerJ
publisher: PeerJ Inc.
publication name: PeerJ
issn: 2167-8359
items: BMSC-derived exosomal miR-27a-3p and miR-196b-5p regulate bone remodeling in ovariectomized rats
items: Comparative analysis of combined phosphorus and drought stress-responses in two winter wheat
items: Population dynamics and resource availability drive seasonal shifts in the consumptive and competitive impacts of introduced house mice (Mus musculus) on an island ecosystem
items: Cultivation has selected for a wider niche and large range shifts in maize
items: Genome-wide identification, characterization and expression analysis of HAK genes and decoding their role in responding to potassium deficiency and abiotic stress in Medicago truncatula
items: Dynamics of soil properties and bacterial community structure by mulched fertigation system in semi-arid area of Northeast China
items: Six-minute rowing test: a valid and reliable method for assessing power output in amateur male rowers
items: Ovarian development, spawning season, size at maturity and fecundity of Acentrogobius viridipunctatus (Valenciennes, 1837) in the Vietnamese Mekong Delta
items: In situ observation of holopelagic Sargassum distribution and aggregation state across the entire North Atlantic from 2011 to 2020
items: Effect of nitrogen fertilizer on seed yield and quality of Kengyilia melanthera (Triticeae, Poaceae)

BMSC-derived exosomal miR-27a-3p and miR-196b-5p regulate bone remodeling in ovariectomized rats
type: item
type: AcademicArticle
description: Background In the bone marrow microenvironment of postmenopausal osteoporosis (PMOP), bone marrow mesenchymal stem cell (BMSC)-derived exosomal miRNAs play an important role in bone formation and bone resorption, although the pathogenesis has yet to be clarified. Methods BMSC-derived exosomes from ovariectomized rats (OVX-Exo) and sham-operated rats (Sham-Exo) were co-cultured with bone marrow-derived macrophages to study their effects on osteoclast differentiation. Next-generation sequencing was utilized to identify the differentially expressed miRNAs (DE-miRNAs) between OVX-Exo and Sham-Exo, while target genes were analyzed using bioinformatics. The regulatory effects of miR-27a-3p and miR-196b-5p on osteogenic differentiation of BMSCs and osteoclast differentiation were verified by gain-of-function and loss-of-function analyses. Results Osteoclast differentiation was significantly enhanced in the OVX-Exo treatment group compared to the Sham-Exo group. Twenty DE-miRNAs were identified between OVX-Exo and Sham-Exo, among which miR-27a-3p and miR-196b-5p promoted the expressions of osteogenic differentiation markers in BMSCs. In contrast, knockdown of miR-27a-3p and miR-196b-5p increased the expressions of osteoclastic markers in osteoclast. These 20 DE-miRNAs were found to target 11435 mRNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed that these target genes were involved in several biological processes and osteoporosis-related signaling pathways. Conclusion BMSC-derived exosomal miR-27a-3p and miR-196b-5p may play a positive regulatory role in bone remodeling.
format: application/pdf
format: text/html
creator: Guohua Lai
creator: Renli Zhao
creator: Weida Zhuang
creator: Zuoxu Hou
creator: Zefeng Yang
creator: Peipei He
creator: Jiachang Wu
creator: Hongxun Sang
subject: Bioinformatics
subject: Cell Biology
subject: Genomics
subject: Orthopedics
subject: Women’s Health
description: doi:10.7717/peerj.13744
publisher: PeerJ Inc.
rights: © 2022 Lai et al.
abstract: Background In the bone marrow microenvironment of postmenopausal osteoporosis (PMOP), bone marrow mesenchymal stem cell (BMSC)-derived exosomal miRNAs play an important role in bone formation and bone resorption, although the pathogenesis has yet to be clarified. Methods BMSC-derived exosomes from ovariectomized rats (OVX-Exo) and sham-operated rats (Sham-Exo) were co-cultured with bone marrow-derived macrophages to study their effects on osteoclast differentiation. Next-generation sequencing was utilized to identify the differentially expressed miRNAs (DE-miRNAs) between OVX-Exo and Sham-Exo, while target genes were analyzed using bioinformatics. The regulatory effects of miR-27a-3p and miR-196b-5p on osteogenic differentiation of BMSCs and osteoclast differentiation were verified by gain-of-function and loss-of-function analyses. Results Osteoclast differentiation was significantly enhanced in the OVX-Exo treatment group compared to the Sham-Exo group. Twenty DE-miRNAs were identified between OVX-Exo and Sham-Exo, among which miR-27a-3p and miR-196b-5p promoted the expressions of osteogenic differentiation markers in BMSCs. In contrast, knockdown of miR-27a-3p and miR-196b-5p increased the expressions of osteoclastic markers in osteoclast. These 20 DE-miRNAs were found to target 11435 mRNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed that these target genes were involved in several biological processes and osteoporosis-related signaling pathways. Conclusion BMSC-derived exosomal miR-27a-3p and miR-196b-5p may play a positive regulatory role in bone remodeling.
bibliographic citation: Lai et al. (2022) BMSC-derived exosomal miR-27a-3p and miR-196b-5p regulate bone remodeling in ovariectomized rats. PeerJ 10:e13744 https://doi.org/10.7717/peerj.13744
date submitted: 2022-02-21
date accepted: 2022-06-27
issued: 2022-09-22
is part of: PeerJ
license: https://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Lai
  given name: Guohua
author list: Agent
  family name: Zhao
  given name: Renli
author list: Agent
  family name: Zhuang
  given name: Weida
author list: Agent
  family name: Hou
  given name: Zuoxu
author list: Agent
  family name: Yang
  given name: Zefeng
author list: Agent
  family name: He
  given name: Peipei
author list: Agent
  family name: Wu
  given name: Jiachang
author list: Agent
  family name: Sang
  given name: Hongxun
doi: 10.7717/peerj.13744
volume: 10
issn: 2167-8359
publication name: PeerJ
publication date: 2022-09-22
copyright: ©2022 Lai et al.
attribution name: Lai et al.

Comparative analysis of combined phosphorus and drought stress-responses in two winter wheat
type: item
type: AcademicArticle
description: Phosphorus stress and drought stress are common abiotic stresses for wheat. In this study, two winter wheat varieties “Xindong20” and “Xindong23” were cultured in a hydroponic system using Hoagland nutrient solution and treated with drought stress under conventional (CP: 1.0 mmol/L) and low (LP: 0.05 mmol/L) phosphorus levels. Under drought stress, the root growth was better under LP than under CP. Under LP, root phosphorus content was increased by 94.2% in Xindong20 and decreased by 48.9% in Xindong23 at 3 d after re-watering, compared with those at 0 d under drought stress. However, the potassium (K) content was the highest among the four elements studied and the phosphorus (P) and calcium (Ca) content were reduced in the root of the two varieties. Under CP, the zinc (Zn) content was higher than that under LP in Xindong23. The GeneChip analysis showed that a total of 4,577 and 202 differentially expressed genes (DEGs) were detected from the roots of Xindong20 and Xindong23, respectively. Among them, 89.9% of DEGs were involved in organelles and vesicles in Xindong20, and 69.8% were involved in root anatomical structure, respiratory chain, electron transport chain, ion transport, and enzyme activity in Xindong23. Overall, LP was superior to CP in mitigating drought stress on wheat, and the regulatory genes were also different in the two varieties. Xindong20 had higher drought tolerance for more up-regulated genes involved in the responses compared to Xindong23.
format: application/pdf
format: text/html
creator: Xiangchi Zhang
creator: Chao Li
creator: Weidan Lu
creator: Xiaoli Wang
creator: Bin Ma
creator: Kaiyong Fu
creator: Chunyan Li
creator: Cheng Li
subject: Agricultural Science
subject: Biochemistry
subject: Molecular Biology
subject: Plant Science
description: doi:10.7717/peerj.13887
publisher: PeerJ Inc.
rights: © 2022 Zhang et al.
abstract: Phosphorus stress and drought stress are common abiotic stresses for wheat. In this study, two winter wheat varieties “Xindong20” and “Xindong23” were cultured in a hydroponic system using Hoagland nutrient solution and treated with drought stress under conventional (CP: 1.0 mmol/L) and low (LP: 0.05 mmol/L) phosphorus levels. Under drought stress, the root growth was better under LP than under CP. Under LP, root phosphorus content was increased by 94.2% in Xindong20 and decreased by 48.9% in Xindong23 at 3 d after re-watering, compared with those at 0 d under drought stress. However, the potassium (K) content was the highest among the four elements studied and the phosphorus (P) and calcium (Ca) content were reduced in the root of the two varieties. Under CP, the zinc (Zn) content was higher than that under LP in Xindong23. The GeneChip analysis showed that a total of 4,577 and 202 differentially expressed genes (DEGs) were detected from the roots of Xindong20 and Xindong23, respectively. Among them, 89.9% of DEGs were involved in organelles and vesicles in Xindong20, and 69.8% were involved in root anatomical structure, respiratory chain, electron transport chain, ion transport, and enzyme activity in Xindong23. Overall, LP was superior to CP in mitigating drought stress on wheat, and the regulatory genes were also different in the two varieties. Xindong20 had higher drought tolerance for more up-regulated genes involved in the responses compared to Xindong23.
bibliographic citation: Zhang et al. (2022) Comparative analysis of combined phosphorus and drought stress-responses in two winter wheat. PeerJ 10:e13887 https://doi.org/10.7717/peerj.13887
date submitted: 2021-11-29
date accepted: 2022-07-21
issued: 2022-09-22
is part of: PeerJ
license: https://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Zhang
  given name: Xiangchi
author list: Agent
  family name: Li
  given name: Chao
author list: Agent
  family name: Lu
  given name: Weidan
author list: Agent
  family name: Wang
  given name: Xiaoli
author list: Agent
  family name: Ma
  given name: Bin
author list: Agent
  family name: Fu
  given name: Kaiyong
author list: Agent
  family name: Li
  given name: Chunyan
author list: Agent
  family name: Li
  given name: Cheng
doi: 10.7717/peerj.13887
volume: 10
issn: 2167-8359
publication name: PeerJ
publication date: 2022-09-22
copyright: © 2022 Zhang et al.
attribution name: Zhang et al.

Population dynamics and resource availability drive seasonal shifts in the consumptive and competitive impacts of introduced house mice (Mus musculus) on an island ecosystem
type: item
type: AcademicArticle
description: Background House mice (Mus musculus) are widespread and invasive on many islands where they can have both direct and indirect impacts on native ecological communities. Given their opportunistic, omnivorous nature the consumptive and competitive impacts of house mice on islands have the potential to vary over time in concert with resource availability and mouse population dynamics. Methods We examined the ecological niche of invasive house mice on Southeast Farallon Island, California, USA using a combination of mouse trapping, food resource surveys, and stable isotope analysis to better understand their trophic interactions with native flora and fauna. Specifically, we coupled the analysis of seasonal variation in resource availability over a 17-year period (2001–2017), carbon (δ13C) and nitrogen (δ15N) stable isotope values of mouse tissue and prey resources in a single year (2013), and isotopic niche and mixing models to quantify seasonal variation in mouse diets and the potential for resource overlap with native species. Results We found that plants were the most important resource for house mice during the spring months when vegetation is abundant and mouse populations are low following heavy precipitation and declines in mouse abundance during the winter. While still consumed, plants declined in dietary importance throughout the summer and fall as mouse populations increased, and seabird and arthropod resources became relatively more available and consumed by house mice. Mouse abundance peaks and other resource availability are low on the island in the fall months when the isotopic niches of house mice and salamanders overlap significantly indicating the potential for competition, most likely for arthropod prey. Discussion Our results indicate how seasonal shifts in both mouse abundance and resource availability are key factors that mediate the consumptive and competitive impacts of introduced house mice on this island ecosystem. As mice consume and/or compete …
format: application/pdf
format: text/html
creator: Michael J. Polito
creator: Bret Robinson
creator: Pete Warzybok
creator: Russell W. Bradley
subject: Conservation Biology
subject: Ecology
subject: Zoology
description: doi:10.7717/peerj.13904
publisher: PeerJ Inc.
rights: © 2022 Polito et al.
abstract: Background House mice (Mus musculus) are widespread and invasive on many islands where they can have both direct and indirect impacts on native ecological communities. Given their opportunistic, omnivorous nature the consumptive and competitive impacts of house mice on islands have the potential to vary over time in concert with resource availability and mouse population dynamics. Methods We examined the ecological niche of invasive house mice on Southeast Farallon Island, California, USA using a combination of mouse trapping, food resource surveys, and stable isotope analysis to better understand their trophic interactions with native flora and fauna. Specifically, we coupled the analysis of seasonal variation in resource availability over a 17-year period (2001–2017), carbon (δ13C) and nitrogen (δ15N) stable isotope values of mouse tissue and prey resources in a single year (2013), and isotopic niche and mixing models to quantify seasonal variation in mouse diets and the potential for resource overlap with native species. Results We found that plants were the most important resource for house mice during the spring months when vegetation is abundant and mouse populations are low following heavy precipitation and declines in mouse abundance during the winter. While still consumed, plants declined in dietary importance throughout the summer and fall as mouse populations increased, and seabird and arthropod resources became relatively more available and consumed by house mice. Mouse abundance peaks and other resource availability are low on the island in the fall months when the isotopic niches of house mice and salamanders overlap significantly indicating the potential for competition, most likely for arthropod prey. Discussion Our results indicate how seasonal shifts in both mouse abundance and resource availability are key factors that mediate the consumptive and competitive impacts of introduced house mice on this island ecosystem. As mice consume and/or compete …
bibliographic citation: Polito et al. (2022) Population dynamics and resource availability drive seasonal shifts in the consumptive and competitive impacts of introduced house mice (Mus musculus) on an island ecosystem. PeerJ 10:e13904 https://doi.org/10.7717/peerj.13904
date submitted: 2022-02-28
date accepted: 2022-07-26
issued: 2022-09-22
is part of: PeerJ
license: https://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Polito
  given name: Michael J.
author list: Agent
  family name: Robinson
  given name: Bret
author list: Agent
  family name: Warzybok
  given name: Pete
author list: Agent
  family name: Bradley
  given name: Russell W.
doi: 10.7717/peerj.13904
volume: 10
issn: 2167-8359
publication name: PeerJ
publication date: 2022-09-22
copyright: ©2022 Polito et al.
attribution name: Polito et al.

Cultivation has selected for a wider niche and large range shifts in maize
type: item
type: AcademicArticle
description: Background Maize (Zea mays L.) is a staple crop cultivated on a global scale. However, its ability to feed the rapidly growing human population may be impaired by climate change, especially if it has low climatic niche and range lability. One important question requiring clarification is therefore whether maize shows high niche and range lability. Methods We used the COUE scheme (a unified terminology representing niche centroid shift, overlap, unfilling and expansion) and species distribution models to study the niche and range changes between maize and its wild progenitors using occurrence records of maize, lowland teosinte (Zea mays ssp. parviglumis) and highland teosinte (Zea mays ssp. mexicana), respectively, as well as explore the mechanisms underlying the niche and range changes. Results In contrast to maize in Mexico, maize did not conserve its niche inherited from lowland and highland teosinte at the global scale. The niche breadth of maize at the global scale was wider than that of its wild progenitors (ca. 5.21 and 3.53 times wider compared with lowland and highland teosinte, respectively). Compared with its wild progenitors, maize at global scale can survive in regions with colder, wetter climatic conditions, as well as with wider ranges of climatic variables (ca. 4.51 and 2.40 times wider compared with lowland and highland teosinte, respectively). The niche changes of maize were largely driven by human introduction and cultivation, which have exposed maize to climatic conditions different from those experienced by its wild progenitors. Small changes in niche breadth had large effects on the magnitude of range shifts; changes in niche breadth thus merit increased attention. Discussion Our results demonstrate that maize shows wide climatic niche and range lability, and this substantially expanded its realized niche and potential range. Our findings also suggest that niche and range shifts probably triggered by natural and artificial selection in cultivati…
format: application/pdf
format: text/html
creator: Rujing Yang
creator: Runyao Cao
creator: Xiang Gong
creator: Jianmeng Feng
subject: Agricultural Science
subject: Ecology
description: doi:10.7717/peerj.14019
publisher: PeerJ Inc.
rights: © 2022 Yang et al.
abstract: Background Maize (Zea mays L.) is a staple crop cultivated on a global scale. However, its ability to feed the rapidly growing human population may be impaired by climate change, especially if it has low climatic niche and range lability. One important question requiring clarification is therefore whether maize shows high niche and range lability. Methods We used the COUE scheme (a unified terminology representing niche centroid shift, overlap, unfilling and expansion) and species distribution models to study the niche and range changes between maize and its wild progenitors using occurrence records of maize, lowland teosinte (Zea mays ssp. parviglumis) and highland teosinte (Zea mays ssp. mexicana), respectively, as well as explore the mechanisms underlying the niche and range changes. Results In contrast to maize in Mexico, maize did not conserve its niche inherited from lowland and highland teosinte at the global scale. The niche breadth of maize at the global scale was wider than that of its wild progenitors (ca. 5.21 and 3.53 times wider compared with lowland and highland teosinte, respectively). Compared with its wild progenitors, maize at global scale can survive in regions with colder, wetter climatic conditions, as well as with wider ranges of climatic variables (ca. 4.51 and 2.40 times wider compared with lowland and highland teosinte, respectively). The niche changes of maize were largely driven by human introduction and cultivation, which have exposed maize to climatic conditions different from those experienced by its wild progenitors. Small changes in niche breadth had large effects on the magnitude of range shifts; changes in niche breadth thus merit increased attention. Discussion Our results demonstrate that maize shows wide climatic niche and range lability, and this substantially expanded its realized niche and potential range. Our findings also suggest that niche and range shifts probably triggered by natural and artificial selection in cultivati…
bibliographic citation: Yang et al. (2022) Cultivation has selected for a wider niche and large range shifts in maize. PeerJ 10:e14019 https://doi.org/10.7717/peerj.14019
date submitted: 2022-03-23
date accepted: 2022-08-16
issued: 2022-09-22
is part of: PeerJ
license: https://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Yang
  given name: Rujing
author list: Agent
  family name: Cao
  given name: Runyao
author list: Agent
  family name: Gong
  given name: Xiang
author list: Agent
  family name: Feng
  given name: Jianmeng
doi: 10.7717/peerj.14019
volume: 10
issn: 2167-8359
publication name: PeerJ
publication date: 2022-09-22
copyright: © 2022 Yang et al.
attribution name: Yang et al.

Genome-wide identification, characterization and expression analysis of HAK genes and decoding their role in responding to potassium deficiency and abiotic stress in Medicago truncatula
type: item
type: AcademicArticle
description: Background The HAK family is the largest potassium (K+) transporter family, vital in K+ uptake, plant growth, and both plant biotic and abiotic stress responses. Although HAK family members have been characterized and functionally investigated in many species, these genes are still not studied in detail in Medicago truncatula, a good model system for studying legume genetics. Methods In this study, we screened the M. truncatula HAK family members (MtHAKs). Furthermore, we also conducted the identification, phylogenetic analysis, and prediction of conserved motifs of MtHAKs. Moreover, we studied the expression levels of MtHAKs under K+ deficiency, drought, and salt stresses using quantitative real-time PCR (qRT-PCR). Results We identified 20 MtHAK family members and classified them into three clusters based on phylogenetic relationships. Conserved motif analyses showed that all MtHAK proteins besides MtHAK10 contained the highly conserved K+ transport domain (GVVYGDLGTSPLY). qRT-PCR analysis showed that several MtHAK genes in roots were induced by abiotic stress. In particular, MtHAK15, MtHAK17, and MtHAK18 were strongly up-regulated in the M. truncatula roots under K+ deficiency, drought, and salt stress conditions, thereby implying that these genes are good candidates for high-affinity K+ uptake and therefore have essential roles in drought and salt tolerance. Discussions Our results not only provided the first genetic description and evolutionary relationships of the K+ transporter family in M. truncatula, but also the potential information responding to K+ deficiency and abiotic stresses, thereby laying the foundation for molecular breeding of stress-resistant legume crops in the future.
format: application/pdf
format: text/html
creator: Yanxue Zhao
creator: Lei Wang
creator: Pengcheng Zhao
creator: Zhongjie Liu
creator: Siyi Guo
creator: Yang Li
creator: Hao Liu
subject: Agricultural Science
subject: Bioinformatics
subject: Genomics
subject: Plant Science
description: doi:10.7717/peerj.14034
publisher: PeerJ Inc.
rights: © 2022 Zhao et al.
abstract: Background The HAK family is the largest potassium (K+) transporter family, vital in K+ uptake, plant growth, and both plant biotic and abiotic stress responses. Although HAK family members have been characterized and functionally investigated in many species, these genes are still not studied in detail in Medicago truncatula, a good model system for studying legume genetics. Methods In this study, we screened the M. truncatula HAK family members (MtHAKs). Furthermore, we also conducted the identification, phylogenetic analysis, and prediction of conserved motifs of MtHAKs. Moreover, we studied the expression levels of MtHAKs under K+ deficiency, drought, and salt stresses using quantitative real-time PCR (qRT-PCR). Results We identified 20 MtHAK family members and classified them into three clusters based on phylogenetic relationships. Conserved motif analyses showed that all MtHAK proteins besides MtHAK10 contained the highly conserved K+ transport domain (GVVYGDLGTSPLY). qRT-PCR analysis showed that several MtHAK genes in roots were induced by abiotic stress. In particular, MtHAK15, MtHAK17, and MtHAK18 were strongly up-regulated in the M. truncatula roots under K+ deficiency, drought, and salt stress conditions, thereby implying that these genes are good candidates for high-affinity K+ uptake and therefore have essential roles in drought and salt tolerance. Discussions Our results not only provided the first genetic description and evolutionary relationships of the K+ transporter family in M. truncatula, but also the potential information responding to K+ deficiency and abiotic stresses, thereby laying the foundation for molecular breeding of stress-resistant legume crops in the future.
bibliographic citation: Zhao et al. (2022) Genome-wide identification, characterization and expression analysis of HAK genes and decoding their role in responding to potassium deficiency and abiotic stress in Medicago truncatula. PeerJ 10:e14034 https://doi.org/10.7717/peerj.14034
date submitted: 2022-03-15
date accepted: 2022-08-18
issued: 2022-09-22
is part of: PeerJ
license: https://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Zhao
  given name: Yanxue
author list: Agent
  family name: Wang
  given name: Lei
author list: Agent
  family name: Zhao
  given name: Pengcheng
author list: Agent
  family name: Liu
  given name: Zhongjie
author list: Agent
  family name: Guo
  given name: Siyi
author list: Agent
  family name: Li
  given name: Yang
author list: Agent
  family name: Liu
  given name: Hao
doi: 10.7717/peerj.14034
volume: 10
issn: 2167-8359
publication name: PeerJ
publication date: 2022-09-22
copyright: © 2022 Zhao et al.
attribution name: Zhao et al.

Dynamics of soil properties and bacterial community structure by mulched fertigation system in semi-arid area of Northeast China
type: item
type: AcademicArticle
description: The agricultural irrigation and fertigation systems have a non-negligible impact on the soil microenvironment in arid and semi-arid areas. Therefore, studying the processes and changes of soil microenvironment under different plastic mulch drip irrigation systems can reveal the “soil-microbe” mechanism and provide a theoretical support for the optimal irrigation and nutrition management of maize in the semi-arid area of Northeast China. Three treatments were used for this study in the semi-arid area of northeast China, namely; mulched fertigation system (MF), drip irrigation system (DI), and farmers’ practices system (FP). We used high-throughput sequencing to study the soil bacterial community structure targeting the 16S rRNA gene. The agricultural irrigation and fertigation systems significantly affected soil properties. MF significantly increased bacterial abundance and bacterial diversity and richness. Moreover, MF and DI markedly increased some relative abundance of beneficial bacterial. The bacterial network in MF was more conducive to the health and stability of the agroecosystem and the relationships among species in MF bacterial network were more complex. The agricultural irrigation and fertigation systems had indirect effects on community composition and bacterial diversity through soil organic carbon (SOC), ammonium nitrogen ( ${\mathrm{NH}}_{4}^{+}$ NH 4 + -N), nitrate nitrogen ( ${\mathrm{NO}}_{3}^{-}$ NO 3 − -N), pH, moisture, ${\mathrm{NH}}_{4}^{+}$ NH 4 + -N and ${\mathrm{NO}}_{3}^{-}$ NO 3 − -N had indirect effects on yield through bacterial community composition, bacterial diversity and bacterial abundance. These findings suggested that MF was the most effective treatment to improve soil bacterial abundance and diversity, and stabilize the functional quality of soil biological processes.
format: application/pdf
format: text/html
creator: Ling Wang
creator: Meng Wang
creator: Qian Li
creator: Jinjing Zhang
creator: Cuilan Li
creator: Yuhan Yuan
creator: Pan Tan
creator: Hang Liu
subject: Ecology
subject: Microbiology
subject: Soil Science
description: doi:10.7717/peerj.14044
publisher: PeerJ Inc.
rights: © 2022 Wang et al.
abstract: The agricultural irrigation and fertigation systems have a non-negligible impact on the soil microenvironment in arid and semi-arid areas. Therefore, studying the processes and changes of soil microenvironment under different plastic mulch drip irrigation systems can reveal the “soil-microbe” mechanism and provide a theoretical support for the optimal irrigation and nutrition management of maize in the semi-arid area of Northeast China. Three treatments were used for this study in the semi-arid area of northeast China, namely; mulched fertigation system (MF), drip irrigation system (DI), and farmers’ practices system (FP). We used high-throughput sequencing to study the soil bacterial community structure targeting the 16S rRNA gene. The agricultural irrigation and fertigation systems significantly affected soil properties. MF significantly increased bacterial abundance and bacterial diversity and richness. Moreover, MF and DI markedly increased some relative abundance of beneficial bacterial. The bacterial network in MF was more conducive to the health and stability of the agroecosystem and the relationships among species in MF bacterial network were more complex. The agricultural irrigation and fertigation systems had indirect effects on community composition and bacterial diversity through soil organic carbon (SOC), ammonium nitrogen ( ${\mathrm{NH}}_{4}^{+}$ NH 4 + -N), nitrate nitrogen ( ${\mathrm{NO}}_{3}^{-}$ NO 3 − -N), pH, moisture, ${\mathrm{NH}}_{4}^{+}$ NH 4 + -N and ${\mathrm{NO}}_{3}^{-}$ NO 3 − -N had indirect effects on yield through bacterial community composition, bacterial diversity and bacterial abundance. These findings suggested that MF was the most effective treatment to improve soil bacterial abundance and diversity, and stabilize the functional quality of soil biological processes.
bibliographic citation: Wang et al. (2022) Dynamics of soil properties and bacterial community structure by mulched fertigation system in semi-arid area of Northeast China. PeerJ 10:e14044 https://doi.org/10.7717/peerj.14044
date submitted: 2022-04-25
date accepted: 2022-08-21
issued: 2022-09-22
is part of: PeerJ
license: https://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Wang
  given name: Ling
author list: Agent
  family name: Wang
  given name: Meng
author list: Agent
  family name: Li
  given name: Qian
author list: Agent
  family name: Zhang
  given name: Jinjing
author list: Agent
  family name: Li
  given name: Cuilan
author list: Agent
  family name: Yuan
  given name: Yuhan
author list: Agent
  family name: Tan
  given name: Pan
author list: Agent
  family name: Liu
  given name: Hang
doi: 10.7717/peerj.14044
volume: 10
issn: 2167-8359
publication name: PeerJ
publication date: 2022-09-22
copyright: ©2022 Wang et al.
attribution name: Wang et al.

Six-minute rowing test: a valid and reliable method for assessing power output in amateur male rowers
type: item
type: AcademicArticle
description: Background Standardized tests are currently available to assess power output in elite rowers. However, there are no valid and reliable tests to assess power output in amateur rowers. Objective This study aimed to determine the validity and reliability of a 6-min rowing ergometer test (6-minRT) as a predictor of power output (PO) in amateur male rowers. Methods Twelve male amateur rowers were part of the study. All participants were instructed to perform an incremental test (IT), a 6-minRT test, and a retest. The validity of the 6-minRT was determined by comparing maximum oxygen uptake (VO2max) and power output (PO) between the IT and 6-minRT. Reliability included the coefficient of variation (CV), intra-class correlation coefficient (ICC), and mean standard error between the 6-minRT test and retest. The significance level was p < 0.05. Results There was no significant difference in VO2max in both IT and 6-minRT (p = 0.18), while the mean power output (Pmean) generated in the 6-minRT equaled 91.96% of the maximal aerobic power (MAP) generated in the IT (p = 0.004). Reliability analysis for the 6-minRT showed a CV = 0.50% and ICC = 0.97 for distance, a CV = 1.85% and ICC = 0.96 for Pmean. Conclusion From a ventilatory and mechanical point of view, the 6-minRT is a maximally valid test for establishing MAP in amateur rowers. Also, the 6-minRT evidences a high degree of agreement between days. Therefore, the 6-minRT is a valid and reliable test for assessing PO in amateur male rowers.
format: application/pdf
format: text/html
creator: Álvaro Huerta Ojeda
creator: Miguel Riquelme Guerra
creator: Walter Coronado Román
creator: María-Mercedes Yeomans-Cabrera
creator: Rodrigo Fuentes-Kloss
subject: Kinesiology
subject: Sports Medicine
description: doi:10.7717/peerj.14060
publisher: PeerJ Inc.
rights: © 2022 Huerta Ojeda et al.
abstract: Background Standardized tests are currently available to assess power output in elite rowers. However, there are no valid and reliable tests to assess power output in amateur rowers. Objective This study aimed to determine the validity and reliability of a 6-min rowing ergometer test (6-minRT) as a predictor of power output (PO) in amateur male rowers. Methods Twelve male amateur rowers were part of the study. All participants were instructed to perform an incremental test (IT), a 6-minRT test, and a retest. The validity of the 6-minRT was determined by comparing maximum oxygen uptake (VO2max) and power output (PO) between the IT and 6-minRT. Reliability included the coefficient of variation (CV), intra-class correlation coefficient (ICC), and mean standard error between the 6-minRT test and retest. The significance level was p < 0.05. Results There was no significant difference in VO2max in both IT and 6-minRT (p = 0.18), while the mean power output (Pmean) generated in the 6-minRT equaled 91.96% of the maximal aerobic power (MAP) generated in the IT (p = 0.004). Reliability analysis for the 6-minRT showed a CV = 0.50% and ICC = 0.97 for distance, a CV = 1.85% and ICC = 0.96 for Pmean. Conclusion From a ventilatory and mechanical point of view, the 6-minRT is a maximally valid test for establishing MAP in amateur rowers. Also, the 6-minRT evidences a high degree of agreement between days. Therefore, the 6-minRT is a valid and reliable test for assessing PO in amateur male rowers.
bibliographic citation: Huerta Ojeda et al. (2022) Six-minute rowing test: a valid and reliable method for assessing power output in amateur male rowers. PeerJ 10:e14060 https://doi.org/10.7717/peerj.14060
date submitted: 2022-05-13
date accepted: 2022-08-25
issued: 2022-09-22
is part of: PeerJ
license: https://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Huerta Ojeda
  given name: Álvaro
author list: Agent
  family name: Riquelme Guerra
  given name: Miguel
author list: Agent
  family name: Coronado Román
  given name: Walter
author list: Agent
  family name: Yeomans-Cabrera
  given name: María-Mercedes
author list: Agent
  family name: Fuentes-Kloss
  given name: Rodrigo
doi: 10.7717/peerj.14060
volume: 10
issn: 2167-8359
publication name: PeerJ
publication date: 2022-09-22
copyright: © 2022 Huerta Ojeda et al.
attribution name: Huerta Ojeda et al.

Ovarian development, spawning season, size at maturity and fecundity of Acentrogobius viridipunctatus (Valenciennes, 1837) in the Vietnamese Mekong Delta
type: item
type: AcademicArticle
description: This present study provides an overview of the reproductive traits, including ovarian development, spawning season, size at maturity (Lm), and fecundity of Acentrogobius viridipunctatus – a high economic value fish in the Vietnamese Mekong Delta (VMD). A total of 432 females were collected using trawl nets from January to December 2020 at four sites, including Long Huu-Tra Vinh (LHTV), Trung Binh-Soc Trang (TBST), Dien Hai-Bac Lieu (DHBL), and Tan Thuan-Ca Mau (TTCM). The ovarian diameter was seen to increase from 2.09 (stage I) to 6.57 mm (stage V). Histological analysis showed that the goby was a multi-spawner due to the different oocyte stages found in stages IV and V of ovaries. It can release eggs all year-round due to the monthly appearance of ovarian stages IV and V during the study period, with the main peak in the 2–4 months of the wet season noted with the highest value of gonadosomatic index at that time. The Lm increased from 6.6 cm at TBST to 9.4 cm at TTCM. This species displayed relatively high fecundity, ranging from 5,481 to 130,683 eggs/female. The average fecundity of this fish was 27,698 ± 7,983 eggs/female at LHTV, 46,592 ± 7,264 eggs/female at TBST, 23,271 ± 4,985 eggs/female at DHBL, and 31,408 ± 2,515 eggs/female at TTCM. Egg diameter ranged from 0.45 ± 0.01 at DHBL to 0.50 ± 0.01 at TBST. For sustainable exploitation, local governments should ask the fishers to avoid catching fish during the main spawning period, and the fish length at first capture should be >Lm.
format: application/pdf
format: text/html
creator: Quang Minh Dinh
creator: Ton Huu Duc Nguyen
creator: Ngon Trong Truong
creator: Diep Xuan Doan
creator: Tien Thi Kieu Nguyen
subject: Aquaculture, Fisheries and Fish Science
subject: Ecology
subject: Zoology
subject: Freshwater Biology
description: doi:10.7717/peerj.14077
publisher: PeerJ Inc.
rights: © 2022 Dinh et al.
abstract: This present study provides an overview of the reproductive traits, including ovarian development, spawning season, size at maturity (Lm), and fecundity of Acentrogobius viridipunctatus – a high economic value fish in the Vietnamese Mekong Delta (VMD). A total of 432 females were collected using trawl nets from January to December 2020 at four sites, including Long Huu-Tra Vinh (LHTV), Trung Binh-Soc Trang (TBST), Dien Hai-Bac Lieu (DHBL), and Tan Thuan-Ca Mau (TTCM). The ovarian diameter was seen to increase from 2.09 (stage I) to 6.57 mm (stage V). Histological analysis showed that the goby was a multi-spawner due to the different oocyte stages found in stages IV and V of ovaries. It can release eggs all year-round due to the monthly appearance of ovarian stages IV and V during the study period, with the main peak in the 2–4 months of the wet season noted with the highest value of gonadosomatic index at that time. The Lm increased from 6.6 cm at TBST to 9.4 cm at TTCM. This species displayed relatively high fecundity, ranging from 5,481 to 130,683 eggs/female. The average fecundity of this fish was 27,698 ± 7,983 eggs/female at LHTV, 46,592 ± 7,264 eggs/female at TBST, 23,271 ± 4,985 eggs/female at DHBL, and 31,408 ± 2,515 eggs/female at TTCM. Egg diameter ranged from 0.45 ± 0.01 at DHBL to 0.50 ± 0.01 at TBST. For sustainable exploitation, local governments should ask the fishers to avoid catching fish during the main spawning period, and the fish length at first capture should be >Lm.
bibliographic citation: Dinh et al. (2022) Ovarian development, spawning season, size at maturity and fecundity of Acentrogobius viridipunctatus (Valenciennes, 1837) in the Vietnamese Mekong Delta. PeerJ 10:e14077 https://doi.org/10.7717/peerj.14077
date submitted: 2022-06-28
date accepted: 2022-08-27
issued: 2022-09-22
is part of: PeerJ
license: https://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Dinh
  given name: Quang Minh
author list: Agent
  family name: Nguyen
  given name: Ton Huu Duc
author list: Agent
  family name: Truong
  given name: Ngon Trong
author list: Agent
  family name: Doan
  given name: Diep Xuan
author list: Agent
  family name: Nguyen
  given name: Tien Thi Kieu
doi: 10.7717/peerj.14077
volume: 10
issn: 2167-8359
publication name: PeerJ
publication date: 2022-09-22
copyright: © 2022 Dinh et al.
attribution name: Dinh et al.

In situ observation of holopelagic Sargassum distribution and aggregation state across the entire North Atlantic from 2011 to 2020
type: item
type: AcademicArticle
description: Between 2011 and 2020, 6,790 visual observations of holopelagic Sargassum were recorded across the North Atlantic Ocean to describe regional distribution, presence, and aggregation state at hourly and 10 km scales. Influences of oceanographic region and wind/sea conditions as well as temporal trends were considered; marine megafauna associates documented the ecological value of aggregations. Holopelagic Sargassum was present in 64% of observations from the western North Atlantic. Dispersed holopelagic Sargassum fragments and clumps were found in 97% of positive observations whereas aggregated windrows (37%) and mats (1%) were less common. Most field observations noted holopelagic Sargassum in quantities below the AFAI algorithm detection limit for the MODIS sensor. Aggregation state patterns were similar across regions; windrow proportion increased with higher wind speeds. In 8 of 10 years in the Sargasso Sea holopelagic Sargassum was found in over 65% of observations. In contrast, the Tropical Atlantic and Caribbean Sea exhibited greater inter-annual variability (1–88% and 11–78% presence, respectively) that did not align with extremes in central Atlantic holopelagic Sargassum areal coverage determined from satellite observations. Megafauna association patterns varied by taxonomic group. While some study regions were impacted by holopelagic Sargassum dynamics in the equatorial Atlantic, the Sargasso Sea had consistently high presence and operated independently. Field observations capture important dynamics occurring at fine spatiotemporal scales, including transient aggregation processes and ecological value for megafauna associates, and therefore remain essential to future studies of holopelagic Sargassum.
format: application/pdf
format: text/html
creator: Deborah S. Goodwin
creator: Amy N.S. Siuda
creator: Jeffrey M. Schell
subject: Biogeography
subject: Marine Biology
subject: Plant Science
subject: Spatial and Geographic Information Science
subject: Biological Oceanography
description: doi:10.7717/peerj.14079
publisher: PeerJ Inc.
rights: © 2022 Goodwin et al.
abstract: Between 2011 and 2020, 6,790 visual observations of holopelagic Sargassum were recorded across the North Atlantic Ocean to describe regional distribution, presence, and aggregation state at hourly and 10 km scales. Influences of oceanographic region and wind/sea conditions as well as temporal trends were considered; marine megafauna associates documented the ecological value of aggregations. Holopelagic Sargassum was present in 64% of observations from the western North Atlantic. Dispersed holopelagic Sargassum fragments and clumps were found in 97% of positive observations whereas aggregated windrows (37%) and mats (1%) were less common. Most field observations noted holopelagic Sargassum in quantities below the AFAI algorithm detection limit for the MODIS sensor. Aggregation state patterns were similar across regions; windrow proportion increased with higher wind speeds. In 8 of 10 years in the Sargasso Sea holopelagic Sargassum was found in over 65% of observations. In contrast, the Tropical Atlantic and Caribbean Sea exhibited greater inter-annual variability (1–88% and 11–78% presence, respectively) that did not align with extremes in central Atlantic holopelagic Sargassum areal coverage determined from satellite observations. Megafauna association patterns varied by taxonomic group. While some study regions were impacted by holopelagic Sargassum dynamics in the equatorial Atlantic, the Sargasso Sea had consistently high presence and operated independently. Field observations capture important dynamics occurring at fine spatiotemporal scales, including transient aggregation processes and ecological value for megafauna associates, and therefore remain essential to future studies of holopelagic Sargassum.
bibliographic citation: Goodwin et al. (2022) In situ observation of holopelagic Sargassum distribution and aggregation state across the entire North Atlantic from 2011 to 2020. PeerJ 10:e14079 https://doi.org/10.7717/peerj.14079
date submitted: 2022-06-10
date accepted: 2022-08-29
issued: 2022-09-22
is part of: PeerJ
license: https://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Goodwin
  given name: Deborah S.
author list: Agent
  family name: Siuda
  given name: Amy N.S.
author list: Agent
  family name: Schell
  given name: Jeffrey M.
doi: 10.7717/peerj.14079
volume: 10
issn: 2167-8359
publication name: PeerJ
publication date: 2022-09-22
copyright: © 2022 Goodwin et al.
attribution name: Goodwin et al.

Effect of nitrogen fertilizer on seed yield and quality of Kengyilia melanthera (Triticeae, Poaceae)
type: item
type: AcademicArticle
description: Widely distributed in the alpine sandy grassland in east Qinghai-Tibet Plateau (QTP), Kengyilia melanthera is considered as an ideal pioneer grass for the restoration of degraded and desertification grassland in the region. Under the special ecological and climatic conditions in the northwest Sichuan plateau located in east QTP, it is of great significance to optimize the amount of nitrogen fertilizer for the seed production of this species. The impact of nitrogen (N) fertilizer application on seed yield and quality of K. melanthera ‘Aba’, the only domesticated variety in the Kengyilia genus of Poaceae, was investigated based on two-year field experiments in the northwestern Sichuan plateau. The results showed that with the increase of N fertilizer application, the number of tillers, number of fertile tillers, 1,000-seed weight and seed yield of this species increased likewise. The optimum N fertilizer rate deduced in the present study was 180 kg·hm−2, where the number of fertile tillers 1,000-seed weight and seed yield reached the peak values. Interestingly, the standard germination rate, germination energy, accelerated aging germination rate, dehydrogenase and acid phosphatase activity of seeds were not affected by the increasing the input of N fertilizer. The comprehensive evaluation of membership function showed that the optimal N fertilizer treatment was 180 kg·hm−2 both for 2016 and 2017. This study provided a certain practical suggestion for the improvement of seed production of K. melanthera in the northwest Sichuan plateau.
format: application/pdf
format: text/html
creator: Shuai Yuan
creator: Yao Ling
creator: Yi Xiong
creator: Chenglin Zhang
creator: Lina Sha
creator: Minghong You
creator: Xiong Lei
creator: Shiqie Bai
creator: Xiao Ma
subject: Agricultural Science
subject: Ecology
subject: Plant Science
subject: Soil Science
subject: Ecotoxicology
description: doi:10.7717/peerj.14101
publisher: PeerJ Inc.
rights: © 2022 Yuan et al.
abstract: Widely distributed in the alpine sandy grassland in east Qinghai-Tibet Plateau (QTP), Kengyilia melanthera is considered as an ideal pioneer grass for the restoration of degraded and desertification grassland in the region. Under the special ecological and climatic conditions in the northwest Sichuan plateau located in east QTP, it is of great significance to optimize the amount of nitrogen fertilizer for the seed production of this species. The impact of nitrogen (N) fertilizer application on seed yield and quality of K. melanthera ‘Aba’, the only domesticated variety in the Kengyilia genus of Poaceae, was investigated based on two-year field experiments in the northwestern Sichuan plateau. The results showed that with the increase of N fertilizer application, the number of tillers, number of fertile tillers, 1,000-seed weight and seed yield of this species increased likewise. The optimum N fertilizer rate deduced in the present study was 180 kg·hm−2, where the number of fertile tillers 1,000-seed weight and seed yield reached the peak values. Interestingly, the standard germination rate, germination energy, accelerated aging germination rate, dehydrogenase and acid phosphatase activity of seeds were not affected by the increasing the input of N fertilizer. The comprehensive evaluation of membership function showed that the optimal N fertilizer treatment was 180 kg·hm−2 both for 2016 and 2017. This study provided a certain practical suggestion for the improvement of seed production of K. melanthera in the northwest Sichuan plateau.
bibliographic citation: Yuan et al. (2022) Effect of nitrogen fertilizer on seed yield and quality of Kengyilia melanthera (Triticeae, Poaceae). PeerJ 10:e14101 https://doi.org/10.7717/peerj.14101
date submitted: 2022-05-06
date accepted: 2022-09-01
issued: 2022-09-22
is part of: PeerJ
license: https://creativecommons.org/licenses/by/4.0/
author list: Agent
  family name: Yuan
  given name: Shuai
author list: Agent
  family name: Ling
  given name: Yao
author list: Agent
  family name: Xiong
  given name: Yi
author list: Agent
  family name: Zhang
  given name: Chenglin
author list: Agent
  family name: Sha
  given name: Lina
author list: Agent
  family name: You
  given name: Minghong
author list: Agent
  family name: Lei
  given name: Xiong
author list: Agent
  family name: Bai
  given name: Shiqie
author list: Agent
  family name: Ma
  given name: Xiao
doi: 10.7717/peerj.14101
volume: 10
issn: 2167-8359
publication name: PeerJ
publication date: 2022-09-22
copyright: © 2022 Yuan et al.
attribution name: Yuan et al.

PeerJ
type: Periodical
uri: PeerJ
issn: 2167-8359