Doubled Concentration Research Articles

Effects of elevated CO2 and temperature on the performance of a diet specialized neotropical herbivore and its host plant

AbstractLittle is known about the potential responses of ecologically specialized tropical species to atmospheric change and global warming. In 2 years of greenhouse experiments simulating climate change impacts, we quantified the effects of mean ambient temperature, elevated temperature (Te), current ambient CO2 concentration ([CO2]a), and doubled CO2 concentration ([CO2]e) on biomass, growth rate, and foliar chemistry of the morning glory vine, Camonea umbellata. In addition, we measured the impacts of climate change simulations on the performance and survival of the tortoise beetle, Acromis sparsa, which feeds exclusively on C. umbellata. Full‐sib A. sparsa larval broods were divided into cohorts. Each cohort was placed in one of four temperature‐CO2 controlled chambers and fed leaves grown in their respective treatments. Vines growing in [CO2]e more than doubled their biomass and their leaves expanded faster. The [CO2]a and Te treatments interacted to yield the greatest foliar [C]. Vines in [CO2]e and Te had the greatest C:N ratios, the lowest availability of nitrogen, and highest larval mortality. Whereas pupae were smaller and suffered lower survival in Te, pupal mass and survival increased in both the [CO2]e and Te treatments. Overall, the simultaneous elevation of both [CO2] and temperature caused declines in host quality, larval survivorship, and pupal mortality that were not observed when only one climate factor was altered. Based on this first tropical experimental study, we predict that C. umbellata will benefit from elevation of temperature and atmospheric [CO2] by altering its foliar chemistry to the detriment of its diet‐specialized herbivore enemy.Abstract in Spanish is available with online material.

Increasing concentrations of dietary threonine, tryptophan, and glycine improve growth performance and intestinal health with decreasing stress responses in broiler chickens raised under multiple stress conditions

The current study aimed to compare the effects of increasing concentrations of dietary threonine (Thr), tryptophan (Trp), and glycine (Gly) on growth performance, stress biomarkers, and intestinal function in broiler chickens under multiple stress conditions. Five hundred sixty broiler chickens at 21 d old were randomly allotted to 5 treatments with 8 replicates. Birds in a positive control (PC) treatment were raised under low stock density (16.9 birds/m2 per cage) with recommended environmental conditions, whereas birds in 4 treatments were subjected to multiple stress conditions: a cyclic heat stress of 30 ± 0.3 °C for 10 h and 23 ± 0.2 °C for 14 h per day with high stock density (25.3 birds/m2 per cage). A basal diet was assigned to both PC and negative control (NC) treatments. Three additional diets were individually formulated to contain double concentrations of digestible Thr, Trp, or Gly + Ser compared with their concentrations in the basal diet. The experiment lasted for 14 d. Results showed that NC treatment had less growth performance (P < 0.001), jejunal goblet cell counts (P = 0.018), and trans-epithelial electrical resistance (TEER; P < 0.001), but greater (P = 0.026) feather corticosterone (CORT) concentrations than PC treatment. Thr treatment showed the least (P < 0.001) feed conversion ratio (FCR) among treatments under multiple stress conditions. Thr, Trp, and Gly treatments had less (P = 0.026) feather CORT concentrations, but had greater (P < 0.001) TEER than NC treatment. In conclusion, increasing concentrations of dietary Thr, Trp, or Gly improve the growth performance and intestinal health in broiler chickens with decreasing stress response under multiple stress conditions.

Infrared Radiative Effects of Increasing CO2 and CH4 on the Atmosphere in Antarctica Compared to the Arctic

AbstractWe simulated the seasonal temperature evolution in the atmosphere of Antarctica and the Arctic focusing on infrared processes. Contributions by other processes were parametrized and kept fixed throughout the simulations. The model was run for current CO2 and CH4 and for doubled concentrations. For doubling CH4 the warming in Antarctica is restricted to the lowest few hundred meters above the surface while in the Arctic we find a warming in the whole troposphere. We find that the amount of water is the main driver for the differences between both polar regions. When increasing both, CO2 and CH4 from pre‐industrial values to current concentrations, and averaged over the whole troposphere, we find a warming of 0.42 K for the Arctic and a slight cooling of 0.01 K for Antarctica. Our results contribute to the understanding of the lack of warming seen in Antarctica throughout the last decades.

Carvacrol-loaded invasomes efficacy against multidrug resistant isolates of Enterobacteriaceae and housefly

The current study aimed to evaluate the antimicrobial activity of carvacrol-loaded invasomes (CLI) against multidrug-resistant (MDR) Enterobacteriaceae and its mechanical vector, the housefly. CLI were prepared and characterized in the laboratory. Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica serovar Enteritidis, Salmonella enterica subsp. enterica serovar Typhimurium, and Klebsiella oxytoca were among the MDR enterobacteriaceae stains investigated. These strains were first isolated and identified from naturally infected chickens. The antibacterial activity of CLI against the MDR isolates was evaluated using the diffusion method. In addition, the insecticidal activity of CLI against housefly larvae and pupae was tested. The MDR index of all evaluated isolates was greater than 20%, indicating that they were all multidrug-resistant. CLI decreased the growth of all isolates except S. Typhimurium and P. aeruginosa at a dose of 0.0125%; however, pure carvacrol inhibited the growth of only Klebsiella oxytoca. Furthermore, both CLI and pure carvacrol inhibited Klebsiella oxytoca growth at different concentrations. CLI inhibited E. coli and S. enteritidis at lower concentrations than pure carvacrol, even at a doubled concentration. Carvacrol and CLI caused significant larval mortality even at low concentrations, with LC50 reached at concentartions of 2.54 and 2.19 µl/ml, respectively. Furthermore, at a low concentration of 3.125 µl/ml, both elicited a high percentage inhibition rate (PIR) in pupae. In conclusion, CLI demonstrated substantial antibacterial action, particularly against MDR isolates, as well as pesticide activity against houseflies.

Elevated temperature and nutrients lead to increased N2O emissions from salt marsh soils from cold and warm climates

Salt marshes can attenuate nutrient pollution and store large amounts of ‘blue carbon’ in their soils, however, the value of sequestered carbon may be partially offset by nitrous oxide (N2O) emissions. Global climate and land use changes result in higher temperatures and inputs of reactive nitrogen (Nr) into coastal zones. Here, we investigated the combined effects of elevated temperature (ambient + 5℃) and Nr (double ambient concentrations) on nitrogen processing in marsh soils from two climatic regions (Quebec, Canada and Louisiana, U.S.) with two vegetation types, Sporobolus alterniflorus (= Spartina alterniflora) and Sporobolus pumilus (= Spartina patens), using 24-h laboratory incubation experiments. Potential N2O fluxes increased from minor sinks to major sources following elevated treatments across all four marsh sites. One day of potential N2O emissions under elevated treatments (representing either long-term sea surface warming or short-term ocean heatwaves effects on coastal marsh soil temperatures alongside pulses of N loading) offset 15–60% of the potential annual ambient N2O sink, depending on marsh site and vegetation type. Rates of potential denitrification were generally higher in high latitude than in low latitude marsh soils under ambient treatments, with low ratios of N2O:N2 indicating complete denitrification in high latitude marsh soils. Under elevated temperature and Nr treatments, potential denitrification was lower in high latitude soil but higher in low latitude soil as compared to ambient conditions, with incomplete denitrification observed except in Louisiana S. pumilus. Overall, our findings suggest that a combined increase in temperature and Nr has the potential to reduce salt marsh greenhouse gas (GHG) sinks under future global change scenarios.

BIOCLIM Modeling for Predicting Suitable Habitat for Endangered Tree Tapiscia sinensis (Tapisciaceae) in China

Climate change jeopardizes species survival, particularly for endangered species. This risk extends to the endangered Chinese endemic tree Tapiscia sinensis. The factors underpinning T. sinensis’s habitat distribution are poorly understood, and its potential response to future climate scenarios remains unclear. With six shortlisted climate factors and 117 occurrence records, we modeled T. sinensis’s potential distribution across China using the BIOCLIM model. We applied principal component analysis to examine the primary climate factors restricting its geographical range. The findings indicate that T. sinensis’ range is principally located in China’s middle subtropical climatic zone at low–mid altitudes. The principal component analysis identified two critical factors representing temperature and precipitation. Temperature was the most critical factor limiting T. sinensis distribution, especially the effect of temperature seasonality and isothermality. The habitat suitability model generated by BIOCLIM under current climate conditions demonstrated strong concordance between the predicted suitable areas and the present actual distribution range. These results verify that the model can reliably identify habitats conducive to T. sinensis growth and survival. However, under a hypothetical future climate scenario of doubled atmospheric CO2 concentrations for 2100, the model indicates a precipitous reduction and fragmentation in the areas with excellent suitability conditions. This predicted decline highlights the considerable threats posed by climate change to the long-term survival of this endangered species in China. Our habitat modeling yields critical insights that inform the development of science-based strategies and best practices to improve conservation management plans for research, protection, nursery cultivation, and sustainable planting in China. Habitat suitability knowledge could aid introduction and cultivation efforts for T. sinensis globally in places with analogous climates.

Antiproliferative effect of methanolic extract of Tamarindus indica in C127I cell line

Investigation of natural bioactive compounds that possess antioxidant and anticancer properties have drawn interest in scientific and industrial perspectives. The current study was conducted to assess the antiproliferative action of methanolic extract of seed coat of Tamarindus indica in C127I mouse mammary tumour cell line. 3-(4,5-dimethyl thazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay is performed to assess the cytotoxicity of methanolic extracts of T. indica in the C127I cell line at concentrations of 320, 160, 80, 40, 20, and 10 µg/mL. The half maximal inhibitory concentration (IC50) was then calculated using Graph Pad Prism 5.0. Doxorubicin was used as positive control. After determining IC50, the cells were treated with extract of T. indica at half, IC50 and double IC50 concentrations after being seeded at a concentration of 1x105 cells/mL in 6 well plates. After 24 hours the cells were trypsinised and stained with acridine orange-ethidium bromide (AOEB) to assess the morphology of apoptosis. When the cells were exposed to various doses of the extract, a dose-dependent decrease in cell viability was observed, and the IC50 value of T. indica was estimated to be 13 µg/ml. In the control cells, AO/EB labelling revealed proliferating cells with green fluorescence, but the T. indica extract-treated cells displayed dose dependent shift from orange to red fluorescence. In conclusion, methanolic extract of Tamarindus indica was found to possess antiproliferative effect in C127I cell line comparable to doxorubicin.

Spatial–Temporal Distribution Pattern of Ormosia hosiei in Sichuan under Different Climate Scenarios

Ormosia hosiei is an endemic plant in China listed as a national grade II key protected wild plant with important scientific, economic, and cultural values. This study was designed to predict the potential suitable distribution areas for O. hosiei under current and future climate change and to provide a reference to enhance the species’ conservation and utilization. Based on the actual geographical locations of O. hosiei in Sichuan, we applied two species distribution models (BIOCLIM and DOMAIN) to predict its current and future potential suitable areas and future change patterns. We also analyzed the major climatic variables limiting its geographical distribution with principal component analysis. The results indicated that O. hosiei was mainly distributed in the eastern region of Sichuan and concentrated in the middle subtropical climate zone at relatively low elevations. The principal component analysis identified two critical factors representing temperature and moisture. The temperature was the most critical factor limiting O. hosiei distribution in Sichuan, especially the effect of extreme low temperatures. Both models’ simulation results of potential suitable areas under the current climate scenario showed that the excellent suitable habitat was consistent with the current actual distribution, remaining in the eastern region of Sichuan. Under the future climate scenario with doubled CO2 concentration (2100), both models predicted a sharp decrease in the areas of excellent and very high suitable habitats. The findings can inform strategies and guidelines for O. hosiei research, conservation, nursery production, and cultivation in Sichuan.

Optimasi sistem kultur dan media untuk peningkatan tinggi tunas in vitro kelapa sawit

Optimization of in vitro shoot growth is necessary to shorten the culture time and produce vigorous oil palm plantlets. This research was conducted to determine the best media and culture techniques to accelerate in vitro shoot growth of oil palm. Shoots of oil palm derived from somatic embryogenesis were grown on DF media with two culture systems (solid medium and double-layer) combined with hormone treatments (0.5-1 mg L-1 giberellin/GA3 and 0.5 mg L-1 Benzyl amino purine/BAP or thidiazuron/ TDZ). Further optimization was conducted using different bottle closures (polypropylene screw caps and plastic wraps) and macronutrients (standard or double concentrations). This research was conducted using a completely randomized design (CRD), with each treatment consisting of 5 bottle replications and each bottle consisting of 5 shoots. The results showed that media with double-layer system combined with GA3 (0.5-1 mg L-1) and TDZ (0.5 mg L-1) gave the highest shoot height increment. The use of double-strength macronutrient media combined with screw bottle caps increased shoot height (136-167 %) and decreased shoot tip necrosis (0-24 %). Plastic wrap bottle caps increased shoot tip necrosis (STN), while doubling macronutrients reduced STN. The growth of oil palm shoots began to slow down after 5 weeks of culture. In conclusion, the optimal conditions for in vitro shoot growth of oil palm were at usage of double-layer media added with GA3 0.5-1 mg L-1, TDZ 0.5 mg L-1, and double macronutrients on bottle jars with polypropylene screw caps.

Increasing selenium concentration in Finnish organic milk using participatory action approach

Selenium (Se) is an essential trace element for animals. In Finland, Se supplementary feeding and Se-enriched macronutrient fertilisers are used in conventional farming because the Se availability from soil is extremely low. The objective of this study was to improve Se concentration in organic milk by replacing sodium selenite (SS) in mineral-vitamin mixture with selenium yeast (SY) either completely or partly (50/50). The feeding experiment was conducted on 15 certified organic dairy farms in Eastern Finland during spring 2008. The cross-over design consisted of three treatments (SS treatment, SY treatment, and SS/SY treatment), three experimental periods (28 days each), and three farm groups (different order of treatments). Replacing SS with the same amount (0.2 mg Se kg-1 feed dry matter) of SY more than doubled Se concentration in organic milk and their mixture resulted in slightly lower Se concentrations. In conclusion, SY supplementary feeding is needed to improve Se concentration in organic milk and Se supply to cows, their calves, and consumers.

Kraals or bomas increase soil carbon and fertility across several biomes

Knowledge about how pastoralism and kraaling may contribute to desired global objectives, such as soil fertility, is in danger of being lost. We tested whether short duration kraaling increases soil fertility across various biomes and countries via a meta-analysis (random effects model, n = 12 studies). Kraaling approximately doubled soil concentrations of carbon (C), nitrogen (N), phosphorus (P), potassium (K), and slightly increased pH compared to non-kraaled areas ( p ≤ 0.0158, all meta-analyses). Results support the idea of persistent nutrient hotspots post kraal abandonment as a generalizable phenomenon. Anecdotes from a case study, the Herding 4 Health Model, supported findings. However, inconsistency scores ( I 2 ≥ 90%) indicated that while the average effect size was positive, in some cases the true outcome may in fact be negative. Kraal age did not predict soil fertility in our analysis, possibly due to coarse time intervals. Some studies nevertheless found kraal age to be important, with relatively immobile elements such as P persisting over time while N and K decreased. Using kraals to achieve ‘desirable states’ such as wildlife-livestock coexistence, land restoration, and crop fertilisation will require monitoring, and maintenance of fertility within ecological bounds, ideally with inputs from scientists and pastoralists alike as part of global partnerships.

Understanding the Sensitivity of Grape Terpenes to Jasmonates Using In Vitro Culture and In Vivo Vineyard Experiments.

Terpene volatiles define the flavor of terpenic grape cultivars. However, grape terpene concentrations can vary 2- to 3-fold across seasons and vineyards, impacting vintage quality. The plant hormone methyl jasmonate (MeJA) stimulates grape terpene production but is expensive and can decrease berry weight and maturity. The synthetic jasmonate prohydrojasmon (PDJ) is cost-effective yet has not been evaluated on grape maturity and terpene production. Here, we performed in vitro (berry culture) and in vivo (vineyard) experiments using Gewürztraminer (Vitis vinifera L.) to evaluate the time- and concentration-dependent sensitivity of maturity parameters and terpene content to MeJA and PDJ. In vitro berry weight was reduced by high MeJA and PDJ concentration across timings. Terpenes were most sensitive to low MeJA concentration at veraison (increased 24-fold) in vitro. Moderate PDJ concentration applied at veraison doubled (increased twofold) terpene concentration in vivo without impacting berry weight or maturity. In conclusion, PDJ may provide a solution to mitigate seasonal variability in terpene production in terpenic grape cultivars.

Screening of different Fe(III) and Fe(II) chelate complexes in clonal micropropagation technology of highbush blueberry (Vaccinium corymbosumL.)

The element iron plays a key role in plant physiology. For plant nutrition, chelated forms of iron are preferred. Therefore, in clonal micropropagation media, FeSO4 x 7H2O is usually introduced together with Na2EDTA. At the same time, other effective iron chelates with both carboxyl and phosphorus chelates are known. So far, there are few scientific studies on the effect of iron chelates complexes on blueberry plants underin vitroconditions. Therefore, studies were conducted with different iron chelate complexes in 4 concentrations on highbush blueberry (Vaccinium corymbosumL.) cv. Brigitta Blue in clonal micropropagation technology. The best results were obtained using Fe(III)-DTPA in increased (×1.5) and doubled (×2.0) concentrations, where the multiplication factor was 4.59-4.65.

Impacts of atmospheric CO2 increase and Amazon deforestation on the regional climate: A water budget modelling study

AbstractGlobal air temperature increase has caused changes in the global climate such as droughts, floods and severe events. Land cover shifts and the increase in greenhouse gas emissions can intensify these impacts. Therefore, the application of Specific Warming Level 2 (SWL2) technique has been considered to evaluate the global warming issue in various climate scales, which may induce different responses in the climate system. The objective of this study is to evaluate the impacts of a doubling of current atmospheric CO2 concentrations as well as the influence of deforestation of the Amazon Forest on the climate of South America. In this study, the CPTEC‐BAM1.2 global model was used to simulate these processes. The first scenario of simulations considered doubled atmospheric CO2 concentration (2XCO2 = 776 ppm) and the second scenario is the total conversion of the Amazon Forest to pasture (DEF). In the third scenario both CO2 and deforestation are considered simultaneously (2XCO2 + DEF). A control simulation considers the natural Amazon Forest shape and a steady CO2 concentration of 388 ppm. Results suggest that the temperature increased in all scenarios, the highest increment in the 2XCO2 + DEF experiment (5.4°C in 2XCO2 + DEF, 5.1°C in DEF and 3.2°C in 2XCO2). The model simulated drastic negative rainfall anomalies in each of three scenarios (2XCO2 + DEF: −2.1 mm day−1, 2XCO2: −1.3 mm day−1 and DEF: −0.9 mm day−1). Besides less precipitation and evapotranspiration, shifts in moisture transport were identified in each of the three scenarios. The effect of doubled atmospheric CO2 produces results similar to deforestation for hydrological water budget changes, and total pasture conversion may intensify such changes.

English

The study was carried out to produce a microcapsule powder of total flavonoids and total total phenols of methanol extract of the cashew, using a complex coacervation encapsulation method. In the search for optimal conditions for encapsulation, a three level factorial design was set up, while taking into account factors like time and proportions in Arabic gum and gelatin. The kinetic of encapsulation follows a kinetic of 2nd order which gives polynomial equations of the second degree. The conditions found are respectively 45 min, 30% Arabic gum and 70% gelatin, for an encapsulation yield is 84.37%; the encapsulation rate is 77.9% for the total flavonoids and 76.5% for the total phenols. The powder obtained has a doubled concentration in total flavonoids and total phenols than the raw bark powder. &nbsp; Key words: Encapsulation, complex coacervation, total flavonoids, total phenols, Anacardium occidentale.

Growth and actual leaf temperature modulate CO2responsiveness of monoterpene emissions from holm oak in opposite ways

Abstract. Climate change can profoundly alter volatile organic compound (VOC) emissions from vegetation and thus influence climate evolution. Yet, the short- and long-term effects of elevated CO2 concentrations on emissions in interaction with temperature are not well enough understood, especially for VOCs other than isoprene. To gain additional insight, we conducted a study on holm oak, which is known for its strong foliar monoterpene emissions that are directly linked to their synthesis. We measured CO2-response curves of emissions, CO2–H2O gas exchanges and chlorophyll fluorescence at two assay temperatures (30 and 35 ∘C) on saplings of four populations grown under normal and double CO2 concentrations combined with two temperature growth regimes differing by 5 ∘C (day/night: 25/15 and 30/20 ∘C). A stepwise reduction in CO2 resulted in a decrease in emissions, occasionally preceded by an increase, with the overall decrease in emissions being greater at 35 ∘C than at 30 ∘C assay temperature. During ramping to high CO2, emissions remained mostly unchanged at 35 ∘C, whereas at 30 ∘C they often dropped, especially at the highest CO2 levels (≥ 1200 ppm). In addition to the actual leaf temperature, the high CO2 responsiveness of emissions was modulated by the plant's growth temperature with warm-grown plants being more sensitive than cool-grown plants. In contrast, growth CO2 had no significant effect on the CO2 sensitivity of emissions, although it promoted plant growth and the leaf emission factor. Correlation analyses suggest that the emission response to CO2 depended primarily on the availability of energetic cofactors produced by photosynthetic electron transport. This availability was likely limited by different processes that occurred during CO2 ramping including photooxidative stress and induction of protective and repair mechanisms as well as competition with CO2 fixation and photorespiration. In addition, feedback inhibition of photosynthesis may have played a role, especially in leaves whose emissions were inhibited only at very high CO2 levels. Overall, our results confirm an isoprene-analogous behavior of monoterpene emissions from holm oak. Emissions exhibit a non-linear response curve to CO2 similar to that currently used for isoprene emission in the MEGAN model, with no difference between major individual monoterpene species and plant chemotype. Simulations estimating the annual VOC releases from holm oak leaves at double atmospheric CO2 indicate that the observed high-CO2 inhibition is unlikely to offset the increase in emissions due to the predicted warming.

Meta-analysis of ecosystem services associated with oyster restoration.

Restoration of foundation species promises to reverse environmental degradation and return lost ecosystem services, but a lack of standardized evaluation across projects limits understanding of recovery, especially in marine systems. Oyster reefs are restored to reverse massive global declines and reclaim valuable ecosystem services, but the success of these projects has not been systematically and comprehensively quantified. We synthesized data on ecosystem services associated with oyster restoration from 245 pairs of restored and degraded reefs and 136 pairs of restored and reference reefs across 3500km of U.S. Gulf of Mexico and Atlantic coastlines. On average, restoration was associated with a 21-fold increase in oyster production (mean log response ratio=3.08 [95% confidence interval: 2.58-3.58]), 34-97% enhancement of habitat provisioning (mean community abundance=0.51 [0.41-0.61], mean richness=0.29 [0.19-0.39], and mean biomass=0.69 [0.39-0.99]), 54% more nitrogen removal (mean=0.43 [0.13-0.73]), and 89-95% greater sediment nutrients (mean=0.67 [0.27-1.07]) and organic matter (mean=0.64 [0.44-0.84]) relative to degraded habitats. Moreover, restored reefs matched reference reefs for these ecosystem services. Our results support the continued and expanded use of oyster restoration to enhance ecosystem services of degraded coastal systems and match many functions provided by reference reefs.

Mechanisms for Zonal Mean Wind Responses in the Thermosphere to Doubled CO2 Concentration

AbstractWe explored mechanisms for the thermospheric zonal mean wind responses to doubled CO2 concentration through investigating the zonal mean momentum balance in the thermosphere using GAIA model simulations in June. The analysis shows that ion drag, molecular viscosity, and meridional pressure gradient force vary 3–20 times more than the other forces due to the doubled CO2 concentration. The three forces strongly attenuate each other; consequently, the increase in zonal mean zonal ion drag dominantly strengthens the southward wind (∼15 ms−1 at maximum) in the northern (summer) hemisphere and latitudes north of 35S. This strengthened ion drag was attributed to increased ion density/relative velocity between ions and neutral particles in the northern/southern hemisphere. Southward of 35, the zonal pressure gradient force and the meridional advection of zonal wind strengthen the southward wind by 4–12 ms−1 in total. On the other hand, the zonal wind is mainly altered by increased meridional pressure gradient force (∼15 ms−1 at maximum) caused by a latitudinally asymmetric response of the thermosphere density to increasing CO2 concentration. Our results suggest that the increased ion density in the northern hemisphere is the underlying trigger for the wind responses to increasing CO2 concentration. Furthermore, we show that the meridional advection was mainly (∼70%) due to that of the DW1 tidal component.

Effects of Zinc, Copper and Iron Oxide Nanoparticles on Induced DNA Methylation, Genomic Instability and LTR Retrotransposon Polymorphism in Wheat (Triticum aestivum L.).

Nanomaterials with unique and diverse physico-chemical properties are used in plant science since they improve plant growth and development and offer protection against biotic and abiotic stressors. Previous studies have explored the effects of such nanomaterials on different plant mechanisms, but information about the effects of nanomaterials on induced DNA methylation, genomic instability and LTR retrotransposon polymorphism in wheat is lacking. Therefore, the present study highlights the key role of nanoparticles in DNA methylation and polymorphism in wheat by investigating the effects of ZnO, CuO and γ-Fe3O4 nanoparticles (NPs) on mature embryo cultures of wheat (Triticum aestivum L.). Nanoparticles were supplemented with Murashige and Skoog (MS) basal medium at normal (1X), double (2X) and triple (3X) concentrations. The findings revealed different responses to the polymorphism rate depending on the nanoparticle type and concentration. Genomic template stability (GTS) values were used to compare the changes encountered in iPBS profiles. ZnO, CuO and γ-Fe3O4 NPs increased the polymorphism rate and cytosine methylation compared to the positive control while reducing GTS values. Moreover, non-γ-Fe3O4 NPs treatments and 2X ZnO and CuO NP treatments yielded higher polymorphism percentages in both MspI- and HpaII-digested CRED-iPBS assays and were thus classified as hypermethylation when the average polymorphism percentage for MspI digestion was considered. On the other hand, the 3X concentrations of all nanoparticles decreased HpaII and MspI polymorphism percentages and were thus classified as hypomethylation. The findings revealed that MS medium supplemented with nanoparticles had epigenetic and genotoxic effects.

Effect of elevating luteinizing hormone action using low doses of human chorionic gonadotropin on double ovulation, follicle dynamics, and circulating follicle-stimulating hormone in lactating dairy cows

Double ovulation and twin pregnancy are undesirable traits in dairy cattle. Based on previous physiological observations, we tested the hypothesis that increased LH action [low-dose human chorionic gonadotropin (hCG)] before the expected time of diameter deviation would change circulating FSH concentrations, maximum size of the second largest (F2) and third largest (F3) follicles, and frequency of multiple ovulations in lactating dairy cows with minimal progesterone (P4) concentrations. In replicate 1, multiparous, nonbred lactating Holstein dairy cows (n = 18) had ovulation synchronized. On d 5 after ovulation, all cows had their corpus luteum regressed and were submitted to follicle (≥3 mm) aspiration 24 h later to induce emergence of a new follicular wave. Cows were then randomized to NoP4 (untreated) and NoP4+hCG (100 IU of hCG every 24 h for 4 d after follicle aspiration). Ultrasound evaluations and blood sample collections were performed every 12 h for 7 d after follicle aspiration. All cows were then treated with 200 μg of GnRH to induce ovulation. In replicate 2, cows (n = 16) were resubmitted to similar procedures (i.e., corpus luteum regression, follicle aspiration, randomization, ultrasound evaluations every 12 h, GnRH 7 d after aspiration). However, cows in replicate 2 received an intravaginal P4 device that had been previously used (∼18 d). Only cows with single (n = 15) and double (n = 16) ovulations were used in the analysis. No significant differences were detected for frequency of double ovulation, follicle sizes, and FSH concentrations across replicates (NoP4 vs. LowP4 and NoP4+hCG vs. LowP4+hCG), so data were combined. Double ovulation was 40% for control cows with no hCG (CONT) and 62.5% with hCG (hCG). Double ovulation increased as the maximum size of F2 increased: <9.5 mm and 9.5-11.5 mm (7.7%) and ≥11.5 mm (94.1%). The hCG group had more cows with F2 > 11.5 (69%) than with 9.5 ≥ F2 ≤ 11.5 (25%) and F2 < 9.5 (6%). In agreement, F2 and F3 maximum size were larger in the hCG group, but FSH concentrations were lower after F1 > 8.5 mm compared with CONT. In contrast, FSH concentrations were greater before deviation (F1 closest value to 8.5 mm) in cows with double ovulations than in those with single ovulations, regardless of hCG treatment. In addition, time from aspiration to deviation was shorter in cows with double rather than single ovulation and in cows treated with hCG as a result of faster F1, F2, and F3 growth rates before diameter deviation. In conclusion, greater FSH and follicle growth before deviation seems to be a primary driver of greater frequency of double ovulation in lactating cows with low circulating P4. Moreover, the increase in follicle growth before deviation and in the maximum size of F2 during hCG treatment suggests that increased LH may also have a role in stimulating double ovulation.