Massey Research Online - Browsing by Author "Zhang Y"

Browsing by Author "Zhang Y"

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A Study of the Interaction, Morphology, and Structure in Trypsin-Epigallocatechin-3-Gallate Complexes
(MDPI (Basel, Switzerland), 2021-07-28) Liu J; Ghanizadeh H; Li X; Han Z; Qiu Y; Zhang Y; Chen X; Wang A; Tresserra-Rimbau A; Bresciani L
Understanding the interaction between proteins and polyphenols is of significance to food industries. The aim of this research was to investigate the mode of aggregation for trypsin-EGCG (Epigallocatechin-3-gallate) complexes. For this, the complex was characterized by fluorescence spectroscopy, circular dichroism (CD) spectra, small-angel X-ray scattering (SAXS), and atomic force microscope (AFM) techniques. The results showed that the fluorescence intensity of trypsin-EGCG complexes decreased with increasing the concentration of EGCG, indicating that the interaction between trypsin and EGCG resulted in changes in the microenvironment around fluorescent amino acid residues. The results of CD analysis showed conformational changes in trypsin after binding with EGCG. The results from SAXS analysis showed that the addition of EGCG results in the formation of aggregates of trypsin-EGCG complexes, and increasing the concentration of EGCG resulted in larger aggregates. AFM images showed that the trypsin-EGCG complex formed aggregates of irregular ellipsoidal shapes with the size of about 200 × 400 × 200 nm, with EGCG interconnecting the trypsin particles. Overall, according to these results, it was concluded that the large aggregates of trypsin-EGCG complexes are formed from several small aggregates that are interconnected. The results of this study shed some light on the interaction between digestive enzymes and EGCG.
Aboveground Structural Attributes and Morpho-Anatomical Response Strategies of Bromus valdivianus Phil. and Lolium perenne L. to Severe Soil Water Restriction
(MDPI (Basel, Switzerland), 2023-12-01) Zhang Y; García-Favre J; Hu H; López IF; Ordóñez IP; Cartmill AD; Kemp PD; Głab T
Grass species have a range of strategies to tolerate soil water restriction, which are linked to the environmental conditions at their site of origin. Climate change enhances the relevance of the functional role of anatomical attributes and their contribution as water stress tolerance factors. Morpho-anatomical traits and adjustments that contribute to drought resistance in Lolium perenne L. (Lp) and Bromus valdivianus Phil. (Bv), a temperate humid grass species, were analysed. The structure of the leaves and pseudostems (stems only in Lp) grown at 20–25% field capacity (FC) (water restriction) and 80–85% FC (control) were evaluated by making paraffin sections. In both species, water restriction reduced the thickness of the leaves and pseudostems, along with the size of the vasculature. Bv had long and dense leaf hairs, small and numerous stomata, and other significant adaptive traits under water stress, including thicker pseudostems (p ≤ 0.001), a greatly thickened bundle sheath wall (p ≤ 0.001) in the pseudostem to ensure water flow, and a thickened cuticle covering on leaf surfaces (p ≤ 0.01) to avoid water loss. Lp vascular bundles developed throughout the stem, and under water restriction the xylem vessel walls were strengthened and lignified. Lp leaves had individual traits of a ribbed/corrugated-shaped upper surface, and the stomata were positioned to maintain relative humidity outside the leaf surface. Water restriction significantly changed the bulliform cell depth in Lp (p ≤ 0.05) that contributed to water loss reduction via the curling leaf blade. This study demonstrated that the two grass species, through different morphological traits, were able to adjust their individual tissues and cells in aboveground parts to reach similar physiological functions to reduce water loss with increased water restriction. These attributes explain how both species enhance persistence and resilience under soil water restriction.
Decreasing Defoliation Frequency Enhances Bromus valdivianus Phil. Growth under Low Soil Water Levels and Interspecific Competition
(MDPI (Basel, Switzerland), 2021-07-01) García-Favre J; Zhang Y; López IF; Donaghy DJ; Cranston LM; Kemp PD
Bromus valdivianus Phil. (Bv) is a water stress-tolerant species, but its competitiveness in a diverse pasture may depend on defoliation management and soil moisture levels. This glasshouse study examined the effect of three defoliation frequencies, based on accumulated growing degree days (AGDD) (250, 500, and 1000 AGDD), and two soil water levels (80–85% of field capacity (FC) and 20–25% FC) on Bv growth as monoculture and as a mixture with Lolium perenne L. (Lp). The treatments were applied in a completely randomised block design with four blocks. The above-ground biomass of Bv was lower in the mixture than in the monoculture (p ≤ 0.001). The Bv plants in the mixture defoliated more infrequently (1000 AGDD) showed an increase in root biomass under 20–25% FC compared to 80–85% FC, with no differences measured between soil water levels in the monoculture. Total root length was highest in the mixture with the combination of infrequent defoliation and 20–25% FC. Conversely, frequent defoliation treatments resulted in reduced water-soluble carbohydrate reserves in the tiller bases of plants (p ≤ 0.001), as they allocated assimilates mainly to foliage growth. These results provide evidence that B. valdivianus can increase its competitiveness relative to Lp through the enhancement of the root growth and the energy reserve in the tiller base under drought conditions and infrequent defoliation in a mixture.
Dynamic Gastrointestinal Digestion of Bovine, Caprine and Ovine Milk Reconstituted from Commercial Whole Milk Powders
(MDPI AG, 2024-05-02) Li S; Ye A; Cui J; Zhang Y; Ware L; Miller JC; Abbotts-Holmes H; Roy NC; Singh H; McNabb W; Polidori P
The global dairy market has been increasingly diversified with more dairy product offerings of milk products from different animal species. Meanwhile, milk powders remain the main exported dairy product format due to their ease of transportation. In this work, we studied the structural changes, protein hydrolysis and nutrient delivery during dynamic gastric digestion and small intestinal digestion of cow, goat and sheep milk reconstituted from commercial whole milk powders. The results show that the reconstituted milks digest similarly to processed fresh milk. The digestion behaviors of the three reconstituted ruminant milks are broadly similar (gastric coagulation, kinetics of gastric emptying of protein and fat and the high digestibility in the small intestine) with some differences, which are likely contributed by the processing history of the milk powders. The delivery of individual amino acids to the small intestine differed between the early and late stages of gastric digestion, which were primarily affected by the abundance of amino acids in caseins and whey proteins but also by the difference between milk types associated with their gastric coagulation behaviors. This work showed that powdered milk is similar to fresh processed milk in digestion behavior, and the inherent differences between ruminant milks can be modified by processing treatments.
Elastic Light Scatter Pattern Analysis for the Expedited Detection of Yersinia Species in Pork Mince: Proof of Concept.
(Frontiers Media S.A., 2021-02-17) On SLW; Zhang Y; Gehring A; Patsekin V; Chelikani V; Flint S; Wang H; Billington C; Fletcher GC; Lindsay J; Robinson JP; Fusco V
Isolation of the pathogens Yersinia enterocolitica and Yersinia pseudotuberculosis from foods typically rely on slow (10-21 day) "cold enrichment" protocols before confirmed results are obtained. We describe an approach that yields results in 39 h that combines an alternative enrichment method with culture on a non-selective medium, and subsequent identification of suspect colonies using elastic light scatter (ELS) analysis. A prototype database of ELS profiles from five Yersinia species and six other bacterial genera found in pork mince was established, and used to compare similar profiles of colonies obtained from enrichment cultures from pork mince samples seeded with representative strains of Y. enterocolitica and Y. pseudotuberculosis. The presumptive identification by ELS using computerised or visual analyses of 83/90 colonies in these experiments as the target species was confirmed by partial 16S rDNA sequencing. In addition to seeded cultures, our method recovered two naturally occurring Yersinia strains. Our results indicate that modified enrichment combined with ELS is a promising new approach for expedited detection of foodborne pathogenic yersiniae.
Enhancing health outcomes for Māori elders through an intergenerational cultural exchange and physical activity programme: a cross-sectional baseline study
(Frontiers Media S.A., 2023-12-12) Oetzel JG; Zhang Y; Nock S; Meha P; Huriwaka H; Vercoe M; Tahu T; Urlich J; Warbrick R; Brown G; Keown S; Rewi P; Erueti B; Warbrick I; Jackson A-M; Perry T; Reddy R; Simpson ML; Cameron MP; Hokowhitu B; Rashedi V
BACKGROUND: The study offers baseline data for a strengths-based approach emphasizing intergenerational cultural knowledge exchange and physical activity developed through a partnership with kaumātua (Māori elders) and kaumātua service providers. The study aims to identify the baseline characteristics, along with correlates of five key outcomes. METHODS: The study design is a cross-sectional survey. A total of 75 kaumātua from six providers completed two physical functioning tests and a survey that included dependent variables based in a holistic model of health: health-related quality of life (HRQOL), self-rated health, spirituality, life satisfaction, and loneliness. RESULTS: The findings indicate that there was good reliability and moderate scores on most variables. Specific correlates included the following: (a) HRQOL: emotional support (β = 0.31), and frequent interaction with a co-participant (β = 0.25); (b) self-rated health: frequency of moderate exercise (β = 0.32) and sense of purpose (β = 0.27); (c) spirituality: sense of purpose (β = 0.46), not needing additional help with daily tasks (β = 0.28), and level of confidence with cultural practices (β = 0.20); (d) life satisfaction: sense of purpose (β = 0.57), frequency of interaction with a co-participant (β = -0.30), emotional support (β = 0.25), and quality of relationship with a co-participant (β = 0.16); and (e) lower loneliness: emotional support (β = 0.27), enjoyment interacting with a co-participant (β = 0.25), sense of purpose (β = 0.24), not needing additional help with daily tasks (β = 0.28), and frequency of moderate exercise (β = 0.18). CONCLUSION: This study provides the baseline scores and correlates of important social and health outcomes for the He Huarahi Tautoko (Avenue of Support) programme, a strengths-based approach for enhancing cultural connection and physical activity.
Grazing activity increases decomposition of yak dung and litter in an alpine meadow on the Qinghai-Tibet plateau
(Springer Nature Switzerland AG on behalf of the Royal Netherlands Society of Agricultural Science, 2019-11) Yang C; Zhang Y; Hou F; Millner JP; Wang Z; Chang S; Shang Z
Aims: This study investigated the influences of herbivore grazing intensity and grazing season on decomposition and nutrient release of dung and litter, which aimed to improve our understandings of grazing affecting nutrient cycling in alpine meadows on the Qinghai-Tibetan Platean. Methods: A factorial design experiment comprising 3 grazing intensities (non-grazing, moderate grazing, and heavy grazing) and 2 grazing seasons (summer and winter), was applied to quantify the decomposition and chemistry of dung and litter in an alpine pasture using the litterbag technique. Litterbags were retrieved for analysis of mass loss and nutrient release with 180, 360, 540, and 720 days after placement. Results: Grazing activity accelerated the decomposition of dung and litter and increased nutrient release from dung and litter by increasing soil temperature compared with non-grazing pastures, whereas grazing season had no effect on decomposition. The decomposition time was shorter for dung than that for litter. Conclusions: Herbivores grazing benefited dung and litter decomposition and nutrient cycling directly by increasing soil temperature, which is likely to promote soil microbial activity due to low temperatures in alpine meadows, and indirectly through herbage ingestion and dung deposition which increase the organic debris concentration used for microorganisms growth and reproduction. This study provides insights into the mechanisms of grazing regulating nutrient cycling in alpine ecosystems.
Guest size limitation in metal-organic framework crystal-glass composites
(Royal Society of Chemistry, 2021-03-01) Ashling CW; Macreadie LK; Southern TJF; Zhang Y; McHugh LN; Evans RC; Kaskel S; Telfer SG; Bennett TD
Metal-organic framework crystal-glass composites (MOF CGCs) have previously been formed by embedding crystalline MIL-53(Al) within a ZIF-62 glass (agZIF-62) matrix. Here we highlight thermal stability considerations in the formation of MOF CGCs, and subsequently report the synthesis of two novel MOF CGCs, by incorporating MIL-118 and UL-MOF-1 withinagZIF-62. These new materials, alongside the prototypical MOF CGC, formed using MIL-53(Al), were studied using scanning electron microscopy, powder X-ray diffraction, and gas sorption techniques. The gas uptake in composites formed from MIL-118C and UL-MOF-1 is largely dominated by theagZIF-62 matrix, suggesting that to improve the porosity of the MOF CGC, the matrix porosity must be improved, or a percolation threshold must be overcome.
Increased precipitation enhances soil respiration in a semi-arid grassland on the Loess Plateau, China
(PeerJ Inc., 2021-02-02) Wang Y; Xie Y; Rapson G; Ma H; Jing L; Zhang Y; Zhang J; Li J; Zhu B
BACKGROUND: Precipitation influences the vulnerability of grassland ecosystems, especially upland grasslands, and soil respiration is critical for carbon cycling in arid grassland ecosystems which typically experience more droughty conditions. METHODS: We used three precipitation treatments to understand the effect of precipitation on soil respiration of a typical arid steppe in the Loess Plateau in north-western China. Precipitation was captured and relocated to simulate precipitation rates of 50%, 100%, and 150% of ambient precipitation. RESULTS AND DISCUSSION: Soil moisture was influenced by all precipitation treatments. Shoot biomass was greater, though non-significantly, as precipitation increased. However, both increase and decrease of precipitation significantly reduced root biomass. There was a positive linear relationship between soil moisture and soil respiration in the study area during the summer (July and August), when most precipitation fell. Soil moisture, soil root biomass, pH, and fungal diversity were predictors of soil respiration based on partial least squares regression, and soil moisture was the best of these. CONCLUSION: Our study highlights the importance of increased precipitation on soil respiration in drylands. Precipitation changes can cause significant alterations in soil properties, microbial fungi, and root biomass, and any surplus or transpired moisture is fed back into the climate, thereby affecting the rate of soil respiration in the future.
Integrated transcriptome and proteome analyses reveal potential mechanisms in Stipa breviflora underlying adaptation to grazing
(John Wiley and Sons Australia, Ltd on behalf of Chinese Grassland Society and Lanzhou University, 2024-03-14) Liu Y; Sun S; Zhang Y; Song M; Tian Y; Lockhart PJ; Zhang X; Xu Y; Dang Z; Matthew C
Background: Long-term overgrazing has led to severe degradation of grasslands, posing a significant threat to the sustainable use of grassland resources. Methods: Based on the investigation of changes in functional traits and photosynthetic physiology of Stipa breviflora under no grazing, moderate grazing, and heavy grazing treatments, the changes in expression patterns of genes and proteins associated with different grazing intensities were assessed through integrative transcriptomic and proteomic analyses. Results: Differentially expressed genes and proteins were identified under different grazing intensities. They were mainly related to RNA processing, carbon metabolism, and secondary metabolite biosynthesis. These findings suggest that long-term grazing leads to molecular phenotypic plasticity, affecting various biological processes and metabolic pathways in S. breviflora. Correlation analysis revealed low correlation between the transcriptome and the proteome, indicating a large-scale regulation of gene expression at the posttranscriptional and translational levels during the response of S. breviflora to grazing. The expression profiles of key genes and proteins involved in photosynthesis and phenylpropanoid metabolism pathways suggested their synergistic response to grazing in S. breviflora. Conclusions: Our study provides insight into the adaptation mechanisms of S. breviflora to grazing and provides a scientific basis for the development of more efficient grassland protection and utilization practices.
Juvenile socio-sexual experience determines lifetime sperm expenditure and adult survival in a polygamous moth, Ephestia kuehniella
(Wiley, 8/02/2023) Liu J; He XZ; Zheng X-L; Zhang Y; Wang Q
Male animals often adjust their sperm investment in response to sperm competition environment. To date, only a few studies have investigated how juvenile socio-sexual settings affect sperm production before adulthood and sperm allocation during the first mating. Yet, it is unclear whether juvenile socio-sexual experience (1) determines lifetime sperm production and allocation in any animal species; (2) alters the eupyrene:apyrene sperm ratio in lifetime ejaculates of any lepidopteran insects, and (3) influences lifetime ejaculation patterns, number of matings and adult longevity. Here we used a polygamous moth, Ephestia kuehniella, to address these questions. Upon male adult emergence from juveniles reared at different density and sex ratio, we paired each male with a virgin female daily until his death. We dissected each mated female to count the sperm transferred and recorded male longevity and lifetime number of matings. We demonstrate for the first time that males ejaculated significantly more eupyrenes and apyrenes in their lifetime after their young were exposed to juvenile rivals. Adult moths continued to produce eupyrene sperm, contradicting the previous predictions for lepidopterans. The eupyrene:apyrene ratio in the lifetime ejaculates remained unchanged in all treatments, suggesting that the sperm ratio is critical for reproductive success. Male juvenile exposure to other juveniles regardless of sex ratio caused significantly shorter adult longevity and faster decline in sperm ejaculation over successive matings. However, males from all treatments achieved similar number of matings in their lifetime. This study provides insight into adaptive resource allocation by males in response to juvenile social-sexual environment.
Kaumātua Mana Motuhake Pōi: a study protocol for enhancing wellbeing, social connectedness and cultural identity for Māori elders.
(BioMed Central, 2020-10-02) Hokowhitu B; Oetzel JG; Simpson ML; Nock S; Reddy R; Meha P; Johnston K; Jackson A-M; Erueti B; Rewi P; Warbrick I; Cameron MP; Zhang Y; Ruru S
BACKGROUND: The Aotearoa New Zealand population is ageing accompanied by health and social challenges including significant inequities that exist between Māori and non-Māori around poor ageing and health. Although historically kaumātua (elder Māori) faced a dominant society that failed to realise their full potential as they age, Māori culture has remained steadfast in upholding elders as cultural/community anchors. Yet, many of today's kaumātua have experienced 'cultural dissonance' as the result of a hegemonic dominant culture subjugating an Indigenous culture, leading to generations of Indigenous peoples compelled or forced to dissociate with their culture. The present research project, Kaumātua Mana Motuhake Pōī (KMMP) comprises two interrelated projects that foreground dimensions of wellbeing within a holistic Te Ao Māori (Māori epistemology) view of wellbeing. Project 1 involves a tuakana-teina/peer educator model approach focused on increasing service access and utilisation to support kaumātua with the greatest health and social needs. Project 2 focuses on physical activity and cultural knowledge exchange (including te reo Māori--Māori language) through intergenerational models of learning. METHODS: Both projects have a consistent research design and common set of methods that coalesce around the emphasis on kaupapa kaumatua; research projects led by kaumātua and kaumātua providers that advance better life outcomes for kaumātua and their communities. The research design for each project is a mixed-methods, pre-test and two post-test, staggered design with 2-3 providers receiving the approach first and then 2-3 receiving it on a delayed basis. A pre-test (baseline) of all participants will be completed. The approach will then be implemented with the first providers. There will then be a follow-up data collection for all participants (post-test 1). The second providers will then implement the approach, which will be followed by a final data collection for all participants (post-test 2). DISCUSSION: Two specific outcomes are anticipated from this research; firstly, it is hoped that the research methodology provides a framework for how government agencies, researchers and relevant sector stakeholders can work with Māori communities. Secondly, the two individual projects will each produce a tangible approach that, it is anticipated, will be cost effective in enhancing kaumātua hauora and mana motuhake. TRIAL REGISTRATION: Australia New Zealand Clinical Trial Registry ( ACTRN12620000316909 ). Registered 6 March 2020.
Larval social cues influence testicular investment in an insect
(Oxford University Press, 11/02/2022) Liu J; He XZ; Zheng X-L; Zhang Y; Wang Q
Socio-sexual environment can have critical impacts on reproduction and survival of animals. Consequently, they need to prepare themselves by allocating more resources to competitive traits that give them advantages in the particular social setting they have been perceiving. Evidence shows that a male usually raises his investment in sperm after he detects the current or future increase of sperm competition because relative sperm numbers can determine his paternity share. This leads to the wide use of testis size as an index of the sperm competition level, yet testis size does not always reflect sperm production. To date, it is not clear whether male animals fine-tune their resource allocation to sperm production and other traits as a response to social cues during their growth and development. Using a polygamous insect Ephestia kuehniella, we tested whether and how larval social environment affected sperm production, testis size and body weight. We exposed the male larvae to different juvenile socio-sexual cues and measured these traits. We demonstrate that regardless of sex ratio, group-reared males produced more eupyrenes (fertile and nucleate sperm) but smaller testes than singly-reared ones, and that body weight and apyrene (infertile and anucleate sperm) numbers remained the same across treatments. We conclude that the presence of larval social, but not sexual cues, is responsible for the increase of eupyrene production and decrease of testis size. We suggest that male larvae increase investment in fertile sperm cells and reduce investment in other testicular tissues in the presence of conspecific juvenile cues.
On the gm-Boosted Miller-Effect Minimized Inverter-Cascode Transimpedance Amplifier for Sensor Applications
(IEEE, 2021-10-20) Zhang Y; Hasan SMR; Grujić D
This paper presents the small-signal operation of a gm-boosted inverter-cascode transimpedance amplifier which has not been reported previously and whose comprehensive analysis is not available in any reported article or text-book. A simplified sequential equivalent-circuit method is employed which eliminates the need for complicated circuit analysis techniques. The analysis shows that the gain and the gain-bandwidth of the gm-boosted inverter-cascode transimpedance-amplifier is enhanced by the gain of the gm-boosting amplifier. This is due to the increased output impedance of the TIA, and, the reduced input-referred miller-effect capacitance through miller-effect trade-off employing the gm-boosting loop. To verify the actual performance improvement achieved, circuit simulation results as well as measured experimental results are also provided.
Prevalence and genetic diversity of Theileria equi from horses in Xinjiang Uygur Autonomous region, China.
(Elsevier B.V., 2023-07-01) Zhang Y; Shi Q; Laven R; Li C; He W; Zheng H; Liu S; Lu M; Yang DA; Guo Q; Chahan B
Theileria equi is a tick-borne intracellular apicomplexan protozoan parasite that causes equine theileriosis (ET). ET is an economically important disease with a worldwide distribution that significantly impacts international horse movement. Horses are an essential part of the economy in Xinjiang which is home to ∼10% of all the horses in China. However, there is very limited information on the prevalence and genetic complexity of T. equi in this region. Blood samples from 302 horses were collected from May to September 2021 in Ili, Xinjiang, and subjected to PCR examination for the presence of T. equi. In addition, a Bayesian latent class model was employed to estimate the true prevalence of T. equi, and a phylogenetic analysis was carried out based on the 18S rRNA gene of T. equi isolates. Seventy-two horses (23.8%) were PCR positive. After accounting for the imperfect PCR test using a Bayesian latent class model, the estimated true prevalence differed considerably between age groups, being 10.8% (95%CrI: 5.8% - 17.9%) in ≤ 3-year-old horses and 35.7% (95%CrI: 28.1% - 44.5%) in horses that were > 3 year-old. All T. equi isolates had their 18S rRNA gene (430bp) sequenced and analyzed in order to identify whether there were multiple genotypes of T. equi in the Xinjiang horse population. All of the 18S rRNA genes clustered into one phylogenetic group, clade E, which is thus probably the dominant genotype of T. equi in Xinjiang, China. To summarize, we monitored the prevalence of T. equi in horses of Xinjiang, China, with a focus on the association between age and the occurrence of T. equi by Bayesian modelling, accompanied by the genotyping of T. equi isolates. Obtaining the information on genotypes and age structure is significant in monitoring the spread of T. equi and studying the factors responsible for the distribution.
Pupal cues increase sperm production but not testis size in an insect
(MDPI AG (Basel, Switzerland), 2021-07-28) Liu J; He XZ; Zheng X-L; Zhang Y; Wang Q; Hoffmann KH
Theoretic and empirical studies show that social surroundings experienced by male insects during their larval or adult stage can influence their testicular investment in diverse ways. Although insect pupae do not feed and crawl, they can communicate using sex-specific and/or non-sex specific cues. Yet, it is unknown, in any insect, whether and how male pupae can fine-tune their resource allocation to sperm production and testis size in response to socio-sexual environments. We investigated this question using a moth, Ephestia kuehniella, which produces fertile eupyrene sperm and unfertile apyrene sperm. We held male pupae individually or in groups with different sex ratios, and dissected adults upon eclosion, measured their testis size, and counted both types of sperm. We demonstrated that after exposure to conspecific pupal cues regardless of sex, male pupae increased production of eupyrenes and apyrenes at the same rate but kept testis size unchanged. We suggest that testis size is fixed after pupation because most morphological traits are formed during the larval stage, allowing little room for pupae to adjust testis size. Like adults, male pupae with fully grown testes have sufficient resources to produce more sperm of both types according to the perceived increase in sperm competition risk
Response of Bromus valdivianus (Pasture Brome) Growth and Physiology to Defoliation Frequency Based on Leaf Stage Development
(MDPI (Basel, Switzerland), 2021-10-13) Ordóñez IP; López IF; Kemp PD; Donaghy DJ; Zhang Y; Herrmann P
first_pagesettingsOrder Article Reprints Open AccessArticle Response of Bromus valdivianus (Pasture Brome) Growth and Physiology to Defoliation Frequency Based on Leaf Stage Development by Iván P. Ordóñez 1,2,3ORCID,Ignacio F. López 1,3,*,Peter D. Kemp 1,3ORCID,Daniel J. Donaghy 1,Yongmei Zhang 4ORCID andPauline Herrmann 5 1 School of Agriculture and Environment, Massey University, Private Bag 11-222, Palmerston North 4440, New Zealand 2 Instituto de Investigaciones Agropecuarias, INIA, Kampenaike, Punta Arenas 6212707, Chile 3 Centro de Investigación en Suelos Volcánicos, Universidad Austral de Chile, Valdivia 5091000, Chile 4 Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China 5 Ecole Nationale Supérieure d’Agronomie et des Industries Alimentaires, ENSAIA, 54505 Nancy, France * Author to whom correspondence should be addressed. Agronomy 2021, 11(10), 2058; https://doi.org/10.3390/agronomy11102058 Submission received: 16 September 2021 / Revised: 8 October 2021 / Accepted: 8 October 2021 / Published: 13 October 2021 Downloadkeyboard_arrow_down Browse Figures Review Reports Versions Notes Abstract The increase in drought events due to climate change have enhanced the relevance of species with greater tolerance or avoidance traits to water restriction periods, such as Bromus valdivianus Phil. (B. valdivianus). In southern Chile, B. valdivianus and Lolium perenne L. (L. perenne) coexist; however, the pasture defoliation criterion is based on the physiological growth and development of L. perenne. It is hypothesised that B. valdivianus needs a lower defoliation frequency than L. perenne to enhance its regrowth and energy reserves. Defoliation frequencies tested were based on B. valdivianus leaf stage 2 (LS-2), leaf stage 3 (LS-3), leaf stage 4 (LS-4) and leaf stage 5 (LS-5). The leaf stage development of Lolium perenne was monitored and contrasted with that of B. valdivianus. The study was conducted in a glasshouse and used a randomised complete block design. For Bromus valdivianus, the lamina length, photosynthetic rate, stomatal conductance, tiller number per plant, leaf area, leaf weights, root growth rate, water-soluble carbohydrates (WSCs) and starch were evaluated. Bromus valdivianus maintained six live leaves with three leaves growing simultaneously. When an individual tiller started developing its seventh leaf, senescence began for the second leaf (the first relevant leaf for photosynthesis). Plant herbage mass, the root growth rate and tiller growth were maximised at LS-4 onwards. The highest leaf elongation rate, evaluated through the slope of the lamina elongation curve of a fully expanded leaf, was verified at LS-4. The water-soluble carbohydrates (WSCs) increased at LS-5; however, no statistical differences were found in LS-4. The LS-3 and LS-2 treatments showed a detrimental effect on WSCs and regrowth. The leaf photosynthetic rate and stomatal conductance diminished while the leaf age increased. In conclusion, B. valdivianus is a ‘six-leaf’ species with leaf senescence beginning at LS-4.25. Defoliation at LS-4 and LS-5 was optimum for plant regrowth, maximising the aboveground plant parameters and total WSC accumulation. The LS-4 for B. valdivianus was equivalent to LS-3.5 for L. perenne. No differences related to tiller population in B. valdivianus were found in the different defoliation frequencies.
Synergistic Effect of Redox Dual PdO x/MnOx Cocatalysts on the Enhanced H2 Production Potential of a SnS/α-Fe2O3 Heterojunction via Ethanol Photoreforming.
(American Chemical Society, 2022-11-22) Etemadi H; Soltani T; Yoshida H; Zhang Y; Telfer SG; Buchanan JK; Plieger PG
In the quest for optimal H2 evolution (HE) through ethanol photoreforming, a dual cocatalyst-modified heterocatalyst strategy is utilized. Tin(II) sulfide (SnS) was hybridized with α-Fe2O3 to form the heterocatalyst FeOSnS with a p-n heterojunction structure as confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffusive reflectance spectroscopy (UV-vis DRS), and Brunauer-Emmett-Teller (BET) techniques. PdOx and PdOx /MnOx cocatalysts were loaded onto the FeOSnS heterocatalyst through the impregnation method, as verified by high-resolution transform electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and elemental mapping. Photocatalytic ethanol photoreforming resulted in the production of H2 as the main product with a selectivity of 99% and some trace amounts of CH4. The FeOSnS2-PdOx 2%/MnOx 1% photocatalyst achieved the highest HE rate of 1654 μmol/g, attributed to the synergistic redox contribution of the PdOx and MnOx species.
The Flagellar Transcriptional Regulator FtcR Controls Brucella melitensis 16M Biofilm Formation via a betI-Mediated Pathway in Response to Hyperosmotic Stress
(MDPI (Basel, Switzerland), 2022-09) Guo J; Deng X; Zhang Y; Song S; Zhao T; Zhu D; Cao S; Baryshnikov PI; Cao G; Blair HT; Chen C; Gu X; Liu L; Zhang H
The expression of flagellar proteins in Brucella species likely evolved through genetic transference from other microorganisms, and contributed to virulence, adaptability, and biofilm formation. Despite significant progress in defining the molecular mechanisms behind flagellar gene expression, the genetic program controlling biofilm formation remains unclear. The flagellar transcriptional factor (FtcR) is a master regulator of the flagellar system’s expression, and is critical for B. melitensis 16M’s flagellar biogenesis and virulence. Here, we demonstrate that FtcR mediates biofilm formation under hyperosmotic stress. Chromatin immunoprecipitation with next-generation sequencing for FtcR and RNA sequencing of ftcR-mutant and wild-type strains revealed a core set of FtcR target genes. We identified a novel FtcR-binding site in the promoter region of the osmotic-stress-response regulator gene betI, which is important for the survival of B. melitensis 16M under hyperosmotic stress. Strikingly, this site autoregulates its expression to benefit biofilm bacteria’s survival under hyperosmotic stress. Moreover, biofilm reduction in ftcR mutants is independent of the flagellar target gene fliF. Collectively, our study provides new insights into the extent and functionality of flagellar-related transcriptional networks in biofilm formation, and presents phenotypic and evolutionary adaptations that alter the regulation of B. melitensis 16M to confer increased tolerance to hyperosmotic stress.
Transcriptome-Wide Gene Expression Plasticity in Stipa grandis in Response to Grazing Intensity Differences
(MDPI (Basel, Switzerland), 2021-11-02) Dang Z; Jia Y; Tian Y; Li J; Zhang Y; Huang L; Liang C; Lockhart PJ; Matthew C; Li FY; Hobza R
Organisms have evolved effective and distinct adaptive strategies to survive. Stipa grandis is a representative species for studying the grazing effect on typical steppe plants in the Inner Mongolia Plateau. Although phenotypic (morphological and physiological) variations in S. grandis in response to long-term grazing have been identified, the molecular mechanisms underlying adaptations and plastic responses remain largely unknown. Here, we performed a transcriptomic analysis to investigate changes in gene expression of S. grandis under four different grazing intensities. As a result, a total of 2357 differentially expressed genes (DEGs) were identified among the tested grazing intensities, suggesting long-term grazing resulted in gene expression plasticity that affected diverse biological processes and metabolic pathways in S. grandis. DEGs were identified in RNA-Seq and qRT-PCR analyses that indicated the modulation of the Calvin-Benson cycle and photorespiration metabolic pathways. The key gene expression profiles encoding various proteins (e.g., ribulose-1,5-bisphosphate carboxylase/oxygenase, fructose-1,6-bisphosphate aldolase, glycolate oxidase, etc.) involved in these pathways suggest that they may synergistically respond to grazing to increase the resilience and stress tolerance of S. grandis. Our findings provide scientific clues for improving grassland use and protection and identifying important questions to address in future transcriptome studies.

Browsing by Author "Zhang Y"

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