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S D Ling - One of the best experts on this subject based on the ideXlab platform.
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density dependent feedbacks hysteresis and demography of Overgrazing sea urchins
Ecology, 2019Co-Authors: S D Ling, N Kriegisch, Bailee Woolley, S.e. ReevesAbstract:Sea urchin grazing can result in regime shift from productive kelp beds to sea urchin barren grounds that represent an alternative and stable reef state. Here we examine the stability of urchin barrens by defining the demographics of the Australian urchin Heliocidaris erythrogramma during regime shift to, and maintenance of, barrens. Inverse-logistic modeling of calibrated in situ annual growth increments for five urchin populations, two from kelp beds and three from barrens, demonstrate slowing of urchin growth as availability and consumption of standing and/or drift kelp declines. Population age structures were predicted from observed sizes over four years (2012–2015, n = 5,864 individuals), which indicated stable age distributions for populations both maintaining barrens and actively grazing among kelp beds. Younger age distributions occurred on barrens whereas more mature populations existed within kelp beds, indicating that high recruitment facilitates maintenance of barrens while Overgrazing appeared more reliant on adult urchins grazing from the edges of kelp beds, as opposed to juvenile recruitment among kelp. Leslie-matrix projections indicated potential for unchecked population growth for all study populations, but which varied depending on whether local or regional recruitment rates were modeled. Ultimately, strong density dependence was observed to check population growth; with high-recruitment/high-density populations offset by reduced growth rates and decreased longevity. Increasing disease rates among older urchins in high density populations were consistent with observed density-dependent mortality, while tethering of healthy urchins revealed highest predation on small urchins within kelp beds, suggesting some remnant resilience of declining kelp habitat. Results demonstrate that the greatest opportunity for urchin population control is when reefs exist in the kelp bed state, at which point urchin populations are prone to negative feedback. Conversely, control of urchins on barrens is demonstrably difficult given positive density-dependent feedbacks that act to stabilize population size and which evidently underpin the hysteresis effect governing the persistence of this alternative stable state.
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phase shift dynamics of sea urchin Overgrazing on nutrified reefs
PLOS ONE, 2016Co-Authors: N Kriegisch, S.e. Reeves, Craig R. Johnson, S D LingAbstract:Shifts from productive kelp beds to impoverished sea urchin barrens occur globally and represent a wholesale change to the ecology of sub-tidal temperate reefs. Although the theory of shifts between alternative stable states is well advanced, there are few field studies detailing the dynamics of these kinds of transitions. In this study, sea urchin herbivory (a ‘top-down’ driver of ecosystems) was manipulated over 12 months to estimate (1) the sea urchin density at which kelp beds collapse to sea urchin barrens, and (2) the minimum sea urchin density required to maintain urchin barrens on experimental reefs in the urbanised Port Phillip Bay, Australia. In parallel, the role of one of the ‘bottom-up’ drivers of ecosystem structure was examined by (3) manipulating local nutrient levels and thus attempting to alter primary production on the experimental reefs. It was found that densities of 8 or more urchins m-2 (≥ 427 g m-2 biomass) lead to complete Overgrazing of kelp beds while kelp bed recovery occurred when densities were reduced to ≤ 4 urchins m-2 (≤ 213 g m-2 biomass). This experiment provided further insight into the dynamics of transition between urchin barrens and kelp beds by exploring possible tipping-points which in this system can be found between 4 and 8 urchins m-2 (213 and 427 g m-2 respectively). Local enhancement of nutrient loading did not change the urchin density required for Overgrazing or kelp bed recovery, as algal growth was not affected by nutrient enhancement.
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global regime shift dynamics of catastrophic sea urchin Overgrazing
Philosophical Transactions of the Royal Society B, 2015Co-Authors: S D Ling, C R Johnson, Robert Eric Scheibling, Andrew Rassweiler, Nick T Shears, Sean D Connell, Anne K Salomon, Kjell Magnus Norderhaug, Alejandro Perezmatus, Jose Carlos HernandezAbstract:A pronounced, widespread and persistent regime shift among marine ecosystems is observable on temperate rocky reefs as a result of sea urchin Overgrazing. Here, we empirically define regime-shift dynamics for this grazing system which transitions between productive macroalgal beds and impoverished urchin barrens. Catastrophic in nature, urchin Overgrazing in a well-studied Australian system demonstrates a discontinuous regime shift, which is of particular management concern as recovery of desirable macroalgal beds requires reducing grazers to well below the initial threshold of Overgrazing. Generality of this regime-shift dynamic is explored across 13 rocky reef systems (spanning 11 different regions from both hemispheres) by compiling available survey data (totalling 10 901 quadrats surveyed in situ ) plus experimental regime-shift responses (observed during a total of 57 in situ manipulations). The emergent and globally coherent pattern shows urchin grazing to cause a discontinuous ‘catastrophic’ regime shift, with hysteresis effect of approximately one order of magnitude in urchin biomass between critical thresholds of Overgrazing and recovery. Different life-history traits appear to create asymmetry in the pace of Overgrazing versus recovery. Once shifted, strong feedback mechanisms provide resilience for each alternative state thus defining the catastrophic nature of this regime shift. Importantly, human-derived stressors can act to erode resilience of desirable macroalgal beds while strengthening resilience of urchin barrens, thus exacerbating the risk, spatial extent and irreversibility of an unwanted regime shift for marine ecosystems.
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Overfishing reduces resilience of kelp beds to climate-driven catastrophic phase shift
Proceedings of the National Academy of Sciences, 2009Co-Authors: S D Ling, Stewart D. Frusher, C R Johnson, K R RidgwayAbstract:A key consideration in assessing impacts of climate change is the possibility of synergistic effects with other human-induced stressors. In the ocean realm, climate change and overfishing pose two of the greatest challenges to the structure and functioning of marine ecosystems. In eastern Tasmania, temperate coastal waters are warming at approximately four times the global ocean warming average, representing the fastest rate of warming in the Southern Hemisphere. This has driven range extension of the ecologically important long-spined sea urchin (Centrostephanus rodgersii), which has now commenced catastrophic Overgrazing of productive Tasmanian kelp beds leading to loss of biodiversity and important rocky reef ecosystem services. Coincident with the Overgrazing is heavy fishing of reef-based predators including the spiny lobster Jasus edwardsii. By conducting experiments inside and outside Marine Protected Areas we show that fishing, by removing large predatory lobsters, has reduced the resilience of kelp beds against the climate-driven threat of the sea urchin and thus increased risk of catastrophic shift to widespread sea urchin barrens. This shows that interactions between multiple human-induced stressors can exacerbate nonlinear responses of ecosystems to climate change and limit the adaptive capacity of these systems. Management actions focused on reducing the risk of catastrophic phase shift in ecosystems are particularly urgent in the face of ongoing warming and unprecedented levels of predator removal from the world's oceans.
N Kriegisch - One of the best experts on this subject based on the ideXlab platform.
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Drift-kelp suppresses foraging movement of Overgrazing sea urchins.
Oecologia, 2019Co-Authors: N Kriegisch, S.e. Reeves, Eb Flukes, Craig R. Johnson, Scott D. LingAbstract:Sea urchins have the capacity to destructively overgraze kelp beds and cause a wholesale shift to an alternative and stable ‘urchin barren’ reef state. However, destructive grazing appears labile and contingent on behavioural shift. Changes in supply of allochthonous ‘drift-kelp’ food are hypothesised as a trigger of change in urchin grazing behaviour, yet field tests are lacking. Here we conduct a suite of in situ behavioural surveys and manipulative experiments within kelp beds and on urchin barrens to examine foraging movements and evidence for a behavioural switch to an ‘Overgrazing mode’ by the Australian urchin Heliocidaris erythrogramma (Echinometridae). Tracking urchins using time-lapse photography revealed urchin foraging to conform to a random walk model within kelp beds and on barrens. However, many individuals tended towards local movement within proximal crevices and movement was reduced in kelp beds compared to barrens. Directional movement of urchins toward newly available kelp was experimentally inducible, consistent with locally observed ‘mobile-feeding-fronts’ that develop at barrens-kelp interfaces. Habitat-specific feeding modes were also evidenced by herbivory assays which revealed urchin grazing rates to be high on both drift-kelp and standing kelp on barren grounds, while drift-kelp but not standing kelp was consumed at high rates within kelp beds. Time-lapse tracking of urchin foraging before/after addition of drift-kelp revealed a reduction in foraging across the reef surface after drift-kelp capture. Collectively, results indicate that the availability of drift-kelp is a pivotal trigger in determining urchin feeding modes which thus mediates the shift between alternative stable states for rocky reef ecosystems.
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density dependent feedbacks hysteresis and demography of Overgrazing sea urchins
Ecology, 2019Co-Authors: S D Ling, N Kriegisch, Bailee Woolley, S.e. ReevesAbstract:Sea urchin grazing can result in regime shift from productive kelp beds to sea urchin barren grounds that represent an alternative and stable reef state. Here we examine the stability of urchin barrens by defining the demographics of the Australian urchin Heliocidaris erythrogramma during regime shift to, and maintenance of, barrens. Inverse-logistic modeling of calibrated in situ annual growth increments for five urchin populations, two from kelp beds and three from barrens, demonstrate slowing of urchin growth as availability and consumption of standing and/or drift kelp declines. Population age structures were predicted from observed sizes over four years (2012–2015, n = 5,864 individuals), which indicated stable age distributions for populations both maintaining barrens and actively grazing among kelp beds. Younger age distributions occurred on barrens whereas more mature populations existed within kelp beds, indicating that high recruitment facilitates maintenance of barrens while Overgrazing appeared more reliant on adult urchins grazing from the edges of kelp beds, as opposed to juvenile recruitment among kelp. Leslie-matrix projections indicated potential for unchecked population growth for all study populations, but which varied depending on whether local or regional recruitment rates were modeled. Ultimately, strong density dependence was observed to check population growth; with high-recruitment/high-density populations offset by reduced growth rates and decreased longevity. Increasing disease rates among older urchins in high density populations were consistent with observed density-dependent mortality, while tethering of healthy urchins revealed highest predation on small urchins within kelp beds, suggesting some remnant resilience of declining kelp habitat. Results demonstrate that the greatest opportunity for urchin population control is when reefs exist in the kelp bed state, at which point urchin populations are prone to negative feedback. Conversely, control of urchins on barrens is demonstrably difficult given positive density-dependent feedbacks that act to stabilize population size and which evidently underpin the hysteresis effect governing the persistence of this alternative stable state.
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phase shift dynamics of sea urchin Overgrazing on nutrified reefs
PLOS ONE, 2016Co-Authors: N Kriegisch, S.e. Reeves, Craig R. Johnson, S D LingAbstract:Shifts from productive kelp beds to impoverished sea urchin barrens occur globally and represent a wholesale change to the ecology of sub-tidal temperate reefs. Although the theory of shifts between alternative stable states is well advanced, there are few field studies detailing the dynamics of these kinds of transitions. In this study, sea urchin herbivory (a ‘top-down’ driver of ecosystems) was manipulated over 12 months to estimate (1) the sea urchin density at which kelp beds collapse to sea urchin barrens, and (2) the minimum sea urchin density required to maintain urchin barrens on experimental reefs in the urbanised Port Phillip Bay, Australia. In parallel, the role of one of the ‘bottom-up’ drivers of ecosystem structure was examined by (3) manipulating local nutrient levels and thus attempting to alter primary production on the experimental reefs. It was found that densities of 8 or more urchins m-2 (≥ 427 g m-2 biomass) lead to complete Overgrazing of kelp beds while kelp bed recovery occurred when densities were reduced to ≤ 4 urchins m-2 (≤ 213 g m-2 biomass). This experiment provided further insight into the dynamics of transition between urchin barrens and kelp beds by exploring possible tipping-points which in this system can be found between 4 and 8 urchins m-2 (213 and 427 g m-2 respectively). Local enhancement of nutrient loading did not change the urchin density required for Overgrazing or kelp bed recovery, as algal growth was not affected by nutrient enhancement.
Enrique H. Bucher - One of the best experts on this subject based on the ideXlab platform.
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The effect of fire and Overgrazing disturbes on soil carbon balance in the Dry Chaco forest.
Forest Ecology and Management, 2004Co-Authors: A. Abril, Pablo Barttfeld, Enrique H. BucherAbstract:Abstract It is usually assumed that much of CO 2 released into the atmosphere results from soil degradation in tropical and subtropical land, particularly from deforestation and conversion of forest into cropland and cultivated pastures. Accordingly, a considerable research effort has been devoted to the understanding of soil carbon balance in these ecosystems. By contrast, little attention has been given to disruption of carbon soil balance in arid regions, which is mostly produced by Overgrazing and occasionally fire. We compared soil carbon balance (CO 2 production in relation to soil and litter organic carbon) in areas under varying degrees of disturbance by Overgrazing and fire in the Dry Chaco woodland. Litter and soil were sampled in both dry and wet seasons. Soil carbon under undisturbed conditions was relatively constant throughout the year (range 23–24 g kg −1 ), whereas at sites both burned and grazed carbon values fluctuated markedly (range 31–21 g kg −1 ). In non-grazed, burned areas soil carbon content increased (16%), whereas at burned and overgrazed sites it decreased (38%). Our results suggest that Overgrazing has a more significant, adverse effect on soil carbon balance than fire when both factors act separately. Burned but ungrazed areas appear to show a tendency to recover the initial carbon balance, whereas in chronically overgrazed sites there is a permanent tendency to carbon loss.
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Overgrazing and soil carbon dynamics in the western chaco of argentina
Applied Soil Ecology, 2001Co-Authors: A. Abril, Enrique H. BucherAbstract:Abstract Very little is known about the effect of Overgrazing on carbon loss from soil in semi-arid savannas and woodlands of South America. Soil carbon parameters were measured in a 10,000 ha restoration project in the western Chaco of Argentina (24°43′S and 63°17′W). Three situations were compared: highly restored (HRS), moderately restored (MRS) and highly degraded (HDS). Soil and litter samples were recovered in the dry and wet seasons. SOC and CO2–C values decreased from the HRS (7.0 kg m−2 and 130 g m−2) to the HDS (1.5 kg m−2 and 46 g m−2) whereas the C mineralization rate increased toward the less restored sites (0.96–2.29). Surface-litter C was similar in both sites under restoration (260 and 229 g m−2), being non-existent at the HDS. Leaves from woody species dominated surface-litter in the HRS, whereas grass material was predominant in the MRS. During the wet season, the SOC decreased, whereas both CO2–C and C mineralization rate increased. The magnitude of the between-season differences was highest at the HDS (62% in SOC, 55% in CO2, and 80% in C mineralization rate). We estimated that C loss since introduction of cattle into the forest was 58 Mg ha−1, reaching a total of 2×1015 g at for the entire Chaco. These values are higher than those caused by the conversion of savannas and other ecosystems into agriculture or cultivated pastures. The amount of C fixed in the highly restored site (275 g ha−1 per year) indicates that the Chaco soils have a significant potential as atmospheric carbon sinks.
Jize Zhang - One of the best experts on this subject based on the ideXlab platform.
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comparative metabolome analysis of serum changes in sheep under Overgrazing or light grazing conditions
BMC Veterinary Research, 2019Co-Authors: Jize Zhang, Yang Gao, Huiqin Guo, Yong Ding, Weibo RenAbstract:Overgrazing is a primary contributor to severe reduction in forage quality and production in Inner Mongolia, leading to extensive ecosystem degradation, sheep health impairment and growth performance reduction. Further studies to identify serum biomarkers that reflect changes in sheep health and nutritional status following Overgrazing would be beneficial. We hereby hypothesize that reduced sheep growth performance under Overgrazing conditions would be associated with metabolic and immune response alterations. This study used an untargeted metabolomics analysis by conducting ultra-high-performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) of sheep serum under Overgrazing and light grazing conditions to identify metabolic disruptions in response to Overgrazing. The sheep body weight gains as well as serum biochemical variables associated with immune responses and nutritional metabolism (immunoglobulin G, albumin, glucose, and nonesterified fatty acids) were significantly decreased with Overgrazing compared with light grazing condition. In contrast, other serum parameters such as alanine and aspartate aminotransferase, alkaline phosphatase, total bilirubin, blood urea nitrogen, and interleukin-8 were markedly higher in the Overgrazing group. Principal component analysis discriminated the metabolomes of the light grazing from the Overgrazing group. Multivariate and univariate analyses revealed changes in the serum concentrations of 15 metabolites (9 metabolites exhibited a marked increase, whereas 6 metabolites showed a significant decrease) in the Overgrazing group. Major changes of fatty acid oxidation, bile acid biosynthesis, and purine and protein metabolism were observed. These findings offer metabolic evidence for putative biomarkers for Overgrazing-induced changes in serum metabolism. Target-identification of these particular metabolites may potentially increase our knowledge of the molecular mechanisms of altered immune responses, nutritional metabolism, and reduced sheep growth performance under Overgrazing conditions.
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hepatic transcriptome profile of sheep ovis aries in response to Overgrazing novel genes and pathways revealed
BMC Genetics, 2019Co-Authors: Weibo Ren, Yang Gao, Huiqin Guo, Yong Ding, Warwick Badgery, Jize ZhangAbstract:Overgrazing is a major factor that causes steppe degradation in Inner Mongolian, resulting in extensive ecosystem damage. Scarcity of grass means sheep are smaller and therefore mutton and cashmere production is greatly reduced, which has resulted in massive annual economic losses. Liver is the primary metabolic organ in mammals. It is also the key source of energy supply and detoxification of metabolites in animals, has a close relationship with animal growth. However, investigations on the responses of sheep induced by consequence of Overgrazing, particularly those relating to liver-related molecular mechanisms and related metabolic pathways, remain elusive. The body weight daily gain of sheep, immune organ indices (liver and spleen), and serum parameters related to immune response, protein synthesis and energy supply (IgG, albumin, glucose and non-esterified fatty acid) were significantly lower in the Overgrazing group. Other serum parameters including alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin, blood urea nitrogen and interleukin-6 were significantly higher in the Overgrazing group. For the RNA-Seq results, we identified approximately 50 differentially expressed genes, of which half of were up-regulated and the other half were down-regulated (Overgrazing group versus light grazing group). Bioinformatics analysis identified two enriched KEGG pathways including peroxisome proliferator-activated receptor (PPAR) signaling pathway (related to lipolysis) and ECM-receptor interaction (related to liver injury and apoptosis). Additionally, several of the down-regulated genes were related to detoxification and immune response. Overall, based on the high-throughput RNA sequencing profile integrated with the results of serum biochemical analyses, consequences of lower forage availability and quality under Overgrazing condition induced altered expression levels of genes participating in energy metabolism (particularly lipid metabolism) and detoxification and immune responses, causing lipolysis and impaired health status, which might be key reasons for the reduced growth performance of sheep. This investigation provides a novel foundation for the development of sheep hepatic gene interactive networks that are a response to the degraded forage availability under Overgrazing condition.
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potential molecular mechanisms of Overgrazing induced dwarfism in sheepgrass leymus chinensis analyzed using proteomic data
BMC Plant Biology, 2018Co-Authors: Weibo Ren, Jize Zhang, Huiqin Guo, Xiangyang Hou, Lingqi Kong, Jihong Xie, Chun ChangAbstract:This study was designed to reveal potential molecular mechanisms of long-term Overgrazing-induced dwarfism in sheepgrass (Leymus chinensis). An electrospray ionisation mass spectrometry system was used to generate proteomic data of dwarf sheepgrass from a long-term overgrazed rangeland and normal sheepgrass from a long-term enclosed rangeland. Differentially expressed proteins (DEPs) between dwarf and normal sheepgrass were identified, after which their potential functions and interactions with each other were predicted. The expression of key DEPs was confirmed by high-performance liquid chromatography mass spectrometry (HPLC–MS) using a multiple reaction monitoring method. Compared with normal sheepgrass, a total of 51 upregulated and 53 downregulated proteins were identified in dwarf sheepgrass. The amino acids biosynthesis pathway was differentially enriched between the two conditions presenting DEPs, such as SAT5_ARATH and DAPA_MAIZE. The protein–protein interaction (PPI) network revealed a possible interaction between RPOB2_LEPTE, A0A023H9M8_9STRA, ATPB_DIOEL, RBL_AMOTI and DNAK_GRATL. Four modules were also extracted from the PPI network. The HPLC–MS analysis confirmed the upregulation and downregulation of ATPB_DIOEL and DNAK_GRATL, respectively in dwarf samples compared with in the controls. The upregulated ATPB_DIOEL and downregulated DNAK_GRATL as well as proteins that interact with them, such as RPOB2_LEPTE, A0A023H9M8_9STRA and RBL_AMOTI, may be associated with the long-term Overgrazing-induced dwarfism in sheepgrass.
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long term Overgrazing induced memory decreases photosynthesis of clonal offspring in a perennial grassland plant
Frontiers in Plant Science, 2017Co-Authors: Weibo Ren, Jize Zhang, Huiqin Guo, Xiangyang Hou, Lingqi Kong, Zhiying Liu, Hui WangAbstract:Previous studies of transgenerational plasticity have demonstrated that long-term Overgrazing experienced by Leymus chinensis, an ecologically dominant, rhizomatous grass species in eastern Eurasian temperate grassland, significantly affects its clonal growth in subsequent generations. However, there is a dearth of information on the reasons underlying this Overgrazing-induced memory effect in plant morphological plasticity. We characterized the relationship between a dwarf phenotype and photosynthesis function decline of L. chinensis from the perspective of leaf photosynthesis by using both field measurement and rhizome buds culture cultivated in a greenhouse. Leaf photosynthetic functions (net photosynthetic rate, stomatal conductance, intercellular carbon dioxide concentration, and transpiration rate) were significantly decreased in smaller L. chinensis individuals that were induced to have a dwarf phenotype by being heavily grazed in the field. This decreased photosynthetic function was maintained a generation after greenhouse tests in which grazing was excluded. Both the response of L. chinensis morphological traits and photosynthetic functions in greenhouse were deceased relative to those in the field experiment. Further, there were significant decreases in leaf chlorophyll content and Rubisco enzyme activities of leaves between bud-cultured dwarf and non-dwarf L. chinensis in the greenhouse. Moreover, gene expression patterns showed that the bud-cultured dwarf L. chinensis significantly down-regulated (by 1.86- to 5.33-fold) a series of key genes that regulate photosynthetic efficiency, stomata opening, and chloroplast development compared with the non-dwarf L. chinensis. This is among the first studies revealing a linkage between long-term Overgrazing affecting the transgenerational morphological plasticity of clonal plants and physiologically adaptive photosynthesis function. Overall, clonal transgenerational effects in L. chinensis phenotypic traits heavily involve photosynthetic plasticity.
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Overgrazing induces alterations in the hepatic proteome of sheep ovis aries an itraq based quantitative proteomic analysis
Proteome Science, 2016Co-Authors: Weibo Ren, Huiqin Guo, Yong Ding, Xiangyang Hou, Yuqing Wang, Warwick Badgery, Lingqi Kong, Chun Chang, Chao Jiang, Jize ZhangAbstract:Background The degradation of the steppe of Inner Mongolia, due to Overgrazing, has resulted in ecosystem damage as well as extensive reductions in sheep production. The growth performance of sheep is greatly reduced because of Overgrazing, which triggers massive economic losses every year. The liver is an essential organ that has very important roles in multiple functions, such as nutrient metabolism, immunity and others, which are closely related to animal growth. However, to our knowledge, no detailed studies have evaluated hepatic metabolism adaption in sheep due to Overgrazing. The molecular mechanisms that underlie these effects remain unclear.
Weibo Ren - One of the best experts on this subject based on the ideXlab platform.
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comparative metabolome analysis of serum changes in sheep under Overgrazing or light grazing conditions
BMC Veterinary Research, 2019Co-Authors: Jize Zhang, Yang Gao, Huiqin Guo, Yong Ding, Weibo RenAbstract:Overgrazing is a primary contributor to severe reduction in forage quality and production in Inner Mongolia, leading to extensive ecosystem degradation, sheep health impairment and growth performance reduction. Further studies to identify serum biomarkers that reflect changes in sheep health and nutritional status following Overgrazing would be beneficial. We hereby hypothesize that reduced sheep growth performance under Overgrazing conditions would be associated with metabolic and immune response alterations. This study used an untargeted metabolomics analysis by conducting ultra-high-performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) of sheep serum under Overgrazing and light grazing conditions to identify metabolic disruptions in response to Overgrazing. The sheep body weight gains as well as serum biochemical variables associated with immune responses and nutritional metabolism (immunoglobulin G, albumin, glucose, and nonesterified fatty acids) were significantly decreased with Overgrazing compared with light grazing condition. In contrast, other serum parameters such as alanine and aspartate aminotransferase, alkaline phosphatase, total bilirubin, blood urea nitrogen, and interleukin-8 were markedly higher in the Overgrazing group. Principal component analysis discriminated the metabolomes of the light grazing from the Overgrazing group. Multivariate and univariate analyses revealed changes in the serum concentrations of 15 metabolites (9 metabolites exhibited a marked increase, whereas 6 metabolites showed a significant decrease) in the Overgrazing group. Major changes of fatty acid oxidation, bile acid biosynthesis, and purine and protein metabolism were observed. These findings offer metabolic evidence for putative biomarkers for Overgrazing-induced changes in serum metabolism. Target-identification of these particular metabolites may potentially increase our knowledge of the molecular mechanisms of altered immune responses, nutritional metabolism, and reduced sheep growth performance under Overgrazing conditions.
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hepatic transcriptome profile of sheep ovis aries in response to Overgrazing novel genes and pathways revealed
BMC Genetics, 2019Co-Authors: Weibo Ren, Yang Gao, Huiqin Guo, Yong Ding, Warwick Badgery, Jize ZhangAbstract:Overgrazing is a major factor that causes steppe degradation in Inner Mongolian, resulting in extensive ecosystem damage. Scarcity of grass means sheep are smaller and therefore mutton and cashmere production is greatly reduced, which has resulted in massive annual economic losses. Liver is the primary metabolic organ in mammals. It is also the key source of energy supply and detoxification of metabolites in animals, has a close relationship with animal growth. However, investigations on the responses of sheep induced by consequence of Overgrazing, particularly those relating to liver-related molecular mechanisms and related metabolic pathways, remain elusive. The body weight daily gain of sheep, immune organ indices (liver and spleen), and serum parameters related to immune response, protein synthesis and energy supply (IgG, albumin, glucose and non-esterified fatty acid) were significantly lower in the Overgrazing group. Other serum parameters including alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin, blood urea nitrogen and interleukin-6 were significantly higher in the Overgrazing group. For the RNA-Seq results, we identified approximately 50 differentially expressed genes, of which half of were up-regulated and the other half were down-regulated (Overgrazing group versus light grazing group). Bioinformatics analysis identified two enriched KEGG pathways including peroxisome proliferator-activated receptor (PPAR) signaling pathway (related to lipolysis) and ECM-receptor interaction (related to liver injury and apoptosis). Additionally, several of the down-regulated genes were related to detoxification and immune response. Overall, based on the high-throughput RNA sequencing profile integrated with the results of serum biochemical analyses, consequences of lower forage availability and quality under Overgrazing condition induced altered expression levels of genes participating in energy metabolism (particularly lipid metabolism) and detoxification and immune responses, causing lipolysis and impaired health status, which might be key reasons for the reduced growth performance of sheep. This investigation provides a novel foundation for the development of sheep hepatic gene interactive networks that are a response to the degraded forage availability under Overgrazing condition.
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potential molecular mechanisms of Overgrazing induced dwarfism in sheepgrass leymus chinensis analyzed using proteomic data
BMC Plant Biology, 2018Co-Authors: Weibo Ren, Jize Zhang, Huiqin Guo, Xiangyang Hou, Lingqi Kong, Jihong Xie, Chun ChangAbstract:This study was designed to reveal potential molecular mechanisms of long-term Overgrazing-induced dwarfism in sheepgrass (Leymus chinensis). An electrospray ionisation mass spectrometry system was used to generate proteomic data of dwarf sheepgrass from a long-term overgrazed rangeland and normal sheepgrass from a long-term enclosed rangeland. Differentially expressed proteins (DEPs) between dwarf and normal sheepgrass were identified, after which their potential functions and interactions with each other were predicted. The expression of key DEPs was confirmed by high-performance liquid chromatography mass spectrometry (HPLC–MS) using a multiple reaction monitoring method. Compared with normal sheepgrass, a total of 51 upregulated and 53 downregulated proteins were identified in dwarf sheepgrass. The amino acids biosynthesis pathway was differentially enriched between the two conditions presenting DEPs, such as SAT5_ARATH and DAPA_MAIZE. The protein–protein interaction (PPI) network revealed a possible interaction between RPOB2_LEPTE, A0A023H9M8_9STRA, ATPB_DIOEL, RBL_AMOTI and DNAK_GRATL. Four modules were also extracted from the PPI network. The HPLC–MS analysis confirmed the upregulation and downregulation of ATPB_DIOEL and DNAK_GRATL, respectively in dwarf samples compared with in the controls. The upregulated ATPB_DIOEL and downregulated DNAK_GRATL as well as proteins that interact with them, such as RPOB2_LEPTE, A0A023H9M8_9STRA and RBL_AMOTI, may be associated with the long-term Overgrazing-induced dwarfism in sheepgrass.
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long term Overgrazing induced memory decreases photosynthesis of clonal offspring in a perennial grassland plant
Frontiers in Plant Science, 2017Co-Authors: Weibo Ren, Jize Zhang, Huiqin Guo, Xiangyang Hou, Lingqi Kong, Zhiying Liu, Hui WangAbstract:Previous studies of transgenerational plasticity have demonstrated that long-term Overgrazing experienced by Leymus chinensis, an ecologically dominant, rhizomatous grass species in eastern Eurasian temperate grassland, significantly affects its clonal growth in subsequent generations. However, there is a dearth of information on the reasons underlying this Overgrazing-induced memory effect in plant morphological plasticity. We characterized the relationship between a dwarf phenotype and photosynthesis function decline of L. chinensis from the perspective of leaf photosynthesis by using both field measurement and rhizome buds culture cultivated in a greenhouse. Leaf photosynthetic functions (net photosynthetic rate, stomatal conductance, intercellular carbon dioxide concentration, and transpiration rate) were significantly decreased in smaller L. chinensis individuals that were induced to have a dwarf phenotype by being heavily grazed in the field. This decreased photosynthetic function was maintained a generation after greenhouse tests in which grazing was excluded. Both the response of L. chinensis morphological traits and photosynthetic functions in greenhouse were deceased relative to those in the field experiment. Further, there were significant decreases in leaf chlorophyll content and Rubisco enzyme activities of leaves between bud-cultured dwarf and non-dwarf L. chinensis in the greenhouse. Moreover, gene expression patterns showed that the bud-cultured dwarf L. chinensis significantly down-regulated (by 1.86- to 5.33-fold) a series of key genes that regulate photosynthetic efficiency, stomata opening, and chloroplast development compared with the non-dwarf L. chinensis. This is among the first studies revealing a linkage between long-term Overgrazing affecting the transgenerational morphological plasticity of clonal plants and physiologically adaptive photosynthesis function. Overall, clonal transgenerational effects in L. chinensis phenotypic traits heavily involve photosynthetic plasticity.
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Overgrazing induces alterations in the hepatic proteome of sheep ovis aries an itraq based quantitative proteomic analysis
Proteome Science, 2016Co-Authors: Weibo Ren, Huiqin Guo, Yong Ding, Xiangyang Hou, Yuqing Wang, Warwick Badgery, Lingqi Kong, Chun Chang, Chao Jiang, Jize ZhangAbstract:Background The degradation of the steppe of Inner Mongolia, due to Overgrazing, has resulted in ecosystem damage as well as extensive reductions in sheep production. The growth performance of sheep is greatly reduced because of Overgrazing, which triggers massive economic losses every year. The liver is an essential organ that has very important roles in multiple functions, such as nutrient metabolism, immunity and others, which are closely related to animal growth. However, to our knowledge, no detailed studies have evaluated hepatic metabolism adaption in sheep due to Overgrazing. The molecular mechanisms that underlie these effects remain unclear.
