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At least 19 recordsLinked to original sources
PubMed2025

Decoding nitrogen uptake efficiency in maize and sorghum: insights from comparative gene regulatory networks.

Nitrogen (N) is an essential macronutrient for plant growth and yield, yet optimizing nitrogen use efficiency remains a challenge in agriculture. To better understand the regulatory basis of plant responses to N availability, we constructed a maize-specific nitrogen uptake efficiency gene regulatory network (mNUEGRN) comprising 1625 protein-DNA interactions (PDI) between 70 promoters and 301 transcription factors using enhanced yeast one-hybrid assays. We also projected a sorghum NUE GRN (spNUEGRN) based on maize orthologs and analyzed N-responsive subnetworks in both species using transcriptome profiling under N stress of early deprivation and recovery. Cross-species comparison with an existing Arabidopsis GRN revealed about 18% conserved interaction, corresponding to 11% of the mNUEGRN, particularly within the nitrate assimilation pathways. Notably, bZIP18 and bZIP30 emerged as central regulators in mNUEGRN, forming highly connected feed-forward loops (FFLs). From our time series data, we identified 19 236 and 23 864 differentially expressed genes in maize and sorghum, respectively. Gini correlation analysis uncovered 764 and 638 FFLs in mNUEGRN and spNUEGRN, respectively, of which 22 FFLs in maize and 35 in sorghum were identified in both leaf and root for each species. These FFLs may represent candidate regulatory motifs that contribute to modulating transcriptional responses under fluctuating N conditions, but their potential roles require further investigation. Together, our findings reveal evolutionarily conserved and species-specific regulatory strategies that mediate early N responsiveness, offering a foundation for engineering crops with improved NUE.

Sorghum↗
PubMedDate not supplied

[Effect of humus and microbial inoculates on yield and nitrogen uptake by agricultural plants].

The application of humus had a positive effect on grain and straw yield of paddy and the yield increased with the increasing concentration of humus. The highest dose ((0,05%) corresponding to 1120 kg humus/ha significantly increased the grain and straw yield by 85 and 30 per cent over control. The efficiency of algal inoculation was enhanced in the presence of humus and recorded 41 per cent increase in yield over algae. The nitrogen uptake was also appreciably increased by grain and straw due to humus application. Humus at 0,05 per cent along with algae significantly increased the nitrogen uptake by paddy over algae alone. Root nodulation, growth and yield of gram crop were appreciably increased due to humus application. The grain and straw yield were increased due to humus (0,05%) application showing 32 and 41 per cent increase over control. The efficiency of Rhizobium inoculation was also improved in the presence of humus and the grain and straw yield was significantly increased.

Eukaryota↗
PubMed2025

TaLAC129 is a negative regulator of arbuscular mycorrhizal symbiosis but enhanced the growth and yield of bread wheat.

Arbuscular mycorrhizal (AM) symbiosis enhances nutrient acquisition and stress resilience in plants, yet the genetic mechanisms regulating this interaction in wheat remain poorly understood. This study explores the variation in AM colonization rates across a diverse set of wheat varieties and aims to identify key genes that regulate the wheat-AM symbiosis. Understanding these molecular mechanisms is crucial for improving nutrient uptake efficiency and stress resistance in wheat breeding programs. Here, we conducted a genome-wide association study (GWAS) of 291 wheat varieties and integrated transcriptomic data to identify TaLAC129, a laccase (LAC)-encoding gene, as a critical negative regulator of AM colonization in wheat roots. Overexpression of TaLAC129 significantly increased root LAC activity and lignin content, concurrently suppressing AM colonization. While this suppression reduced nitrogen (N), phosphorus (P), and potassium (K) uptake in stems, leaves, and glumes, it markedly enhanced nutrient utilization efficiency (NUE) in grains. Furthermore, TaLAC129 overexpression improved agronomic traits, including grains per panicle, 1000-grain weight, and overall yield. Our findings reveal the dual role of TaLAC129 in balancing AM symbiosis and nutrient allocation, offering a novel genetic target for breeding wheat varieties with improved yield and nutrient efficiency. This study provides critical insights into the molecular coordination between symbiotic trade-offs and agricultural productivity in cereal crops.

Triticum↗
PubMedDate not supplied

Solute clearance in continuous venovenous hemodialysis. A comparison of cuprophane, polyacrylonitrile, and polysulfone membranes.

Critically ill patients with ARF and MOSF were treated with continuous venovenous hemodialysis (CVVHD). The BSM 22 delivery system (CGH Medical, Denver, CO) and four different dialyzer membranes were used. Vascular access was achieved with a dual lumen catheter placed percutaneously into a large vein. Heparin was used for anticoagulation, and commercially available peritoneal dialysis fluid was used as dialysate. At a fixed blood flow rate of 100 ml/min, the dialysate inflow and outflow rates were regulated to control azotemia and fluid balance. Blood side and dialysate side clearances for urea nitrogen, creatinine, bicarbonate, and lactate were measured. All dialyzer membranes studied provided high urea nitrogen clearance approximating dialysate outflow rate and resulting in excellent control of azotemia. Some of the dialyzer membranes also had high creatinine and bicarbonate clearances. Bicarbonate loss was balanced by lactate uptake with all dialyzers. It is concluded that CVVHD is an efficient and safe therapy for acute renal failure, capable of maintaining nitrogen balance in patients with protein catabolic rates up to 2 g/kg/day. Urea nitrogen clearance is dependent upon dialysate outflow rate rather than the dialyzer membrane type or dialyzer flow geometry, and may prove to be the modality of choice for therapy of acute renal failure in unstable patients with MOSF.

Acrylic Resins↗
PubMed1976

Feeding adaptations in the hairs and tongues of nectar-feeding bats.

Scales on the hairs of pollinating bats spread out at an angle to the main hair shaft. In contrast, the hairs of most bats not associated with plants are relatively smooth. Both megachiropteran and microchiropteran flower-feeding bats show this divaricate scale structure which may aid in the collection of a heavy coating of pollen. Some of the pollen is transferred to subsequent flowers, but most is groomed from the fur and ingested as the only reliable nitrogen source for the bat. The tongues of nectar-feeding bats also show structural modifications which allow efficient uptake of the carbohydrate fraction of the diet. Structural specializations of the hiars and tongue are analogous to those seen in other nectar-feeding animals.

Adaptation, Biological↗
PubMed2025

Sphingobium yanoikuyae 41R9 Enhances Nitrogen Uptake by Modulating Transporter Genes and Root Development in Rapeseed.

Plant growth-promoting rhizobacteria (PGPR) are widely recognized for enhancing the absorption of mineral nutrients by crops. While Sphingobium species have been reported as PGPRs, their capacity to improve nitrogen use efficiency (NUE) and the underlying regulatory mechanisms are not yet fully understood. Here, a strain 41R9, isolated from the rhizosphere of N-deficient rapeseed, was found to significantly enhance the growth performance of rapeseed under both low and normal N conditions. Genomic analysis revealed that strain 41R9 was closely related to Sphingobium yanoikuyae. 15N isotope tracer experiments confirmed that inoculation with strain 41R9 significantly boosted N uptake and translocation in rapeseed roots. Transcriptome profiling demonstrated that strain 41R9 directly upregulated N transporter genes (NRT2.5 and SLAH1/3), facilitating efficient N acquisition. Furthermore, strain 41R9 maintained jasmonic acid (JA) homoeostasis via JAZ-mediated negative feedback, balancing defense responses and root development, thereby improving the plant's N acquisition capacity in the roots. Metabolomic and in vitro assays further demonstrated that strain 41R9 displayed strong chemotaxis towards kaempferol, a N-deficiency-induced root exudate, suggesting kaempferol might as a chemical effector for S. yanoikuyae recruitment. These findings advance our understanding of PGPR-driven mechanisms in enhancing crop NUE and highlight the potential of harnessing PGPRs for sustainable agriculture.

Plant Roots↗
PubMed1989

Management practices to overcome the incidence of grass tetany.

To minimize the incidence of grass tetany, winter pastures should be established on soils containing Mg-rich minerals, drainage should be improved on five-textured soils, legumes should be included in the sward and soil pH should be at least 5.5. Liming acid soils with dolomitic lime increases forage Mg by supplying Mg and by raising soil pH. Calcitic lime applications also can increase Mg availability to plants on soils with adequate Mg. Low rates of application of soluble Mg salts (less than 100 kg/ha of Mg) effectively increase Mg uptake from noncalcareous soils with low cation exchange capacity. Potassium levels in soils and plants should be kept in the lower range of recommended values. Nitrogen application should be regulated to provide the desired level of forage production. Nitrogen fertilizers, especially the nitrate form, stimulate plant Mg uptake if Mg is available in the soil. The most practical and cost-efficient method of supplementing dietary Mg intake is to provide free-choice Mg. Supplements must be palatable and placed in locations frequently used by cow herds. Including a high-energy feed in the supplement may at times increase its preventive effectiveness by increasing Mg absorption and reducing lipolysis. Regardless of the supplement formulation, Mg intake should be monitored on a regular basis, and formulation or management changes should be initiated if Mg consumption is below required levels. In severe grass tetany outbreaks, foliar application of Mg or administration of Mg via the drinking water may be warranted.

Agriculture↗
PubMed1991

Exposure to fumes in typical New Zealand welding operations.

Sixteen welders, welding under typical New Zealand conditions, had ambient air within their welding helmets sampled and analysed for ozone, nitrogen oxides, fluoride, carbon monoxide, aluminium, chromium, iron, nickel, zinc and total dust. Postshift urinary metals were also analysed, and a respiratory questionnaire completed for each welder. Levels above the New Zealand Workplace Exposure Standard (WES) were found for nitrogen dioxide in four welders (two TIG, one MMA and one plasma cutter), and for total chromium in one plasma cutter, who also had a nickel level of 24% of the WES. Dust levels were highest in the plasma cutters, with one reaching 8.67 mg/m3 (WES = 5 mg/m3). Urinary levels however did not indicate excessive short or long term uptake. Where efficient fume extraction was in use, levels of air contaminants were lower than with natural ventilation. Respiratory symptoms were reported by 67% of welders, 38% meeting criteria for chronic bronchitis (relative risk = 2.0). Smoking welders reported more symptoms than nonsmoking welders.

Adult↗
PubMed2026

Silicon-mediated alleviation of mercury toxicity requires coordinated regulation of antioxidant defense, metal homeostasis, and nodule function in mung bean.

Mercury (Hg) contamination and accumulation in agricultural soil represent a major hazardous environmental concern, posing serious threats to living organisms, including plants. Silicon (Si) has been widely recognized to mitigate heavy metal (loid) toxicity; however, the underlying mechanism of Si-mediated mitigation of Hg-stress in mung bean remains unclear. In this study, we addressed this research gap by thoroughly examining the potential effects of Si supplementation on Hg-stressed mung bean plants, with particular emphasis on investigating the possible effects of Si on plant biomass, nodulation traits, antioxidant defense, and expression of metal-transporter and detoxification genes. Our findings demonstrated that Hg stress significantly impaired plant growth by inducing oxidative stress and reducing biological nitrogen fixation efficiency whereas Si application significantly alleviated the Hg-induced toxicity. Specifically, Si increased shoot dry biomass by +113% (2.13-fold), root dry biomass by +60% (1.60-fold), nodule number by +152% (2.52-fold), and nodule dry weight by +273% (3.73-fold) under Hg stress compared to Hg treated plants only. Furthermore, Si enhanced antioxidant defense system, restricted the uptake and accumulation of Hg in different plant tissues, and regulated the expression of genes related to metal transport and detoxification, contributing to improved nodulation and nitrogen fixation under Hg stress. Overall, our findings demonstrate that Si application mitigates the Hg-induced toxicity in mung bean plants by enhancing antioxidant defense, improving nitrogen fixation, regulation of genes involved in metal transport and detoxification, and limiting Hg accumulation.

Vigna radiata↗
PubMed1992

Lowering of plasma glucose concentration in septic cancer-bearing patients: metabolic significance.

Previous work has indicated that 40-50% of glucose intake is oxidized in normal humans with protein-sparing effect. In contrast, the catabolic stressed patient is hyperglycaemic with decreased glucose oxidation and protein wasting. This study evaluated whether the plasma glucose concentration alone would be a reliable indicator of efficient glucose utilization and protein sparing in the critically ill septic cancer patients receiving glucose infusions. Glucose turnover, glucose concentration, nitrogen excretion, oxygen consumption, and glucose oxidation were measured in 8 septic cancer-bearing patients during a glucose infusion of 4.0 mg/kg/min followed by the infusion of insulin with the same glucose load. During glucose infusion without insulin the glucose concentration was 11.8 +/- 1.4 mmol/l, glucose oxidation 10 +/- 5% of glucose tissue uptake, and nitrogen excretion 9.0 +/- 1.3 mg/kg/h. During the euglycaemic clamp the glucose concentration was 3.8 +/- 0.2 mmol/l, glucose oxidation increased to 45 +/- 6% of glucose tissue uptake (p < 0.001), and nitrogen excretion dropped to 6.8 +/- 1.2 mg/kg/h (p < 0.001). The glucose concentration was greater than 10 mmol/l in 4 patients and between 6.9 and 9.3 mmol/l in 4 patients after glucose infusion alone. Despite this difference in initial glucose concentration, normalization of plasma glucose to less than 5 mmol/l with insulin resulted in the same decrease in nitrogen excretion and improvement in glucose oxidation. We conclude that, independent of the initial glucose concentration, maintenance of euglycaemia with insulin appears to be a good indicator of efficient glucose utilization and protein sparing in septic cancer-bearing patients receiving glucose as the primary mode of nutritional support.

Adult↗
PubMed2025

Hyperspectral imaging of grains uncovers the genetic architecture of nitrogen response of development in bread wheat.

UNLABELLED: Unraveling the genetic architecture of nitrogen response of development is critical for improving wheat productivity while reducing nitrogen inputs. In this study, hyperspectral imaging (HSI) was applied to wheat grains obtained from nitrogen-deficient and normal conditions, combined with genome-wide association studies (GWAS), to investigate the nitrogen response of development in a diverse wheat panel. The 1,792 i-traits were acquired via hyperspectral imaging system, which reflect detailed phenotypic assessments of wheat development, capturing subtle variations in nitrogen response. A total of 3,556 significant loci and 3,648 candidate genes were identified. Key candidate genes involved in nitrogen uptake and utilization were identified by integrating agronomic traits with i-traits, including TaARE1-7A, TaPTR9-7B, TaNAR2.1, and Rht-B1. This approach underscores the potential of combining HSI on grains with GWAS to dissect complex traits like nitrogen response, offering valuable genetic insights for breeding nitrogen-efficient wheat varieties and enhancing sustainability in crop production. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11032-025-01609-6.

Bread wheat↗
PubMed1979

Yielding ability of erect- and narrow-leaved rice mutant in heavy manuring and dense planting culture.

A dwarf rice mutant was induced through the chronic exposure of 60Co gamma-rays. This mutant was crossed with a heavy-panicle type variety, and semi-dwarf plants permitting a more efficient distribution of light within the canopy were obtained. They along with current commercial varieties and the parent mutant were assessed for yield components, the yielding ability at three levels of nitrogen fertilizer by varying plant density and several other agronomic traits. The ssmidwarf rice possessed significantly higher rates of net photosynthetic CO2 uptake compared with that of current commercial varieties, and it was improved in yield return by increasing nitrogen application. Manner of display of leaves could be manipulated by induced mutations.

Agriculture↗
PubMed1976

Influence of atmospheric oxygen concentration on acetylene reduction and efficiency of nitrogen fixation in intact Klebsiella pneumoniae.

Oxygen-limited (N2-fixing) chemostat cultures of Klebsiella pneumoniae supplied with a N-free medium were established by introducing low atmospheric O2 concentrations into the gas supply of anaerobic glucose-limited N2-fixing chemostat cultures; the molar growth yield for glucose and the efficiency of N2 fixation (mug N fixed/mg glucose consumed) were increased (by up to 82%) from the anaerobic values. Acetylene-reducing activity was inhibited reversibly by O2 in samples from O2-limited and anaerobic glucose-limited chemostat cultures. Oxygen uptake rates in samples from these chemostat cultures were similar, but C2-H2-reducing activity in samples from O2-limited chemostat cultures was more tolerant of low atmospheric O2 concentrations, in part because of a higher population density. In the absence of glucose, O2 was required at a low atmospheric concentration for C2H2 reduction in samples from either O2-limited or anaerobic glucose-limited chemostat cultures. The possibility is discussed that ATP generated from oxidative phosphorylation can be used for N2 fixation in K. pneumoniae.

Acetylene↗
PubMed2026

Influence of microplastics on microalgal performance during wastewater polishing.

Microplastics (MPs) are emerging contaminants that are increasingly accumulating in aquatic ecosystems due to excessive anthropogenic activity and insufficient mitigation strategies, posing serious environmental and public health risks. Their impact on wastewater (WW) treatment processes remains poorly understood. This study evaluated the effects of five MPs commonly found in WW - polypropylene, polystyrene, polyamide, low-density polyethylene, and high-density polyethylene - on the physiology and bioremediation performance of the microalga Chlorella vulgaris in synthetic WW (SWW). Metabolic responses were assessed via esterase activity and intracellular reactive oxygen species (ROS), while nitrogen (N), phosphorus (P), and glucose removal were monitored to evaluate bioremediation efficiency. MPs inhibited esterase activity and elevated ROS levels, indicating oxidative stress. Nevertheless, C. vulgaris maintained a high bioremediation capacity (> 75 % N, > 60 % P, and > 70 % for glucose). Environmental conditions modulated microalga response to MPs exposure. Under N-limited conditions, C. vulgaris exhibited enhanced nutrient uptake and biomass production, but a 12 h/12 h light/dark photoperiod reduced N removal but stimulated glucose consumption via heterotrophic metabolism. In contrast, C-limited conditions exacerbated oxidative stress and compromised nutrient removal, resulting in residual concentrations exceeding legal limits. These findings highlight that environmental factors can either mitigate or exacerbate the physiological stress induced by MPs, ultimately affecting WW polishing. This work provides a comprehensive insight into the cellular and metabolic effects of MPs on microalgae and supports C. vulgaris as a resilient and sustainable approach for nutrient and carbon removal in MP-contaminated WW systems.

Microalgae↗
PubMed1975

Heterotrophic nutrition of the marine pennate diatom Navicula pavillardi Hustedt.

Navicula pavillardi Hustedt, a marine, littoral, pennate diatom, can grow in the dark on glutamate or on the complex organic supplements tryptone or yeast extract. Growth on glutamate in the dark took place without an initial lag phase, whereas growth on tryptone began only after a 2-day lag phase that could be abolished by the simultaneous presence of glucose. Lactate inhibited growth in the dark on glutamate, but not photoautotrophic growth. Relatively low concentrations of glutamine inhibited photoautotrophic growth. The observed doubling time for heterotrophic growth on glutamate or tryptone was about 70 h, compared with a doubling time of 24 h under optimal photoautotrophic conditions. Glucose did not decrease the doubling time in the dark on tryptone. The assimilation efficiency for glutamate was 41%. The estimated necessary uptake rate for glutamate to account for the observed heterotrophic doubling time on glutamate was close to those measured with isotope techniques. The kinetic parameters for glutamate uptake, which followed Michelis-Menten kinetics, were Ks = 0.018 mM, and Vmax = 7.0 X 10(-10) mumol per cell per minute. Although several amino acids served as sole nitrogen sources for photoautotrophic growth and were demonstrated by the use of isotope techniques to enter the cells, they could not be used as substrates for growth in the dark. Glucose was not taken up to a significant extent except by cells grown in the presence of tryptone. Lactate was taken up only by dark-grown cells. Results of preliminary studies on the metabolic fate of several uniformly labeled amino acids are presented.

Acetates↗
PubMed1977

Bacillus megaterium mutant deficient in membrane-bound adenosine triphosphatase activity.

An adenosine triphosphatase (ATPase) mutant of Bacillus megaterium was isolated and characterized. This mutant (designated A37) was unable to grow on nonfermentable carbon sources and possessed less than 5% of the wild-type ATPase activity. Oxygen uptake by the mutant was comparable to that in the wild type. Sporulation in the wild type occurred in both glucose- and nitrogen-limiting media; however, A37 sporulated only in the nitrogen-limiting medium. The inability of A37 to sporulate in glucose-limiting medium seemed to be due to insufficient adenosine 5'-triphosphate (ATP) levels during the sporulation stages. Fructose, which can generate ATP via substrate-level phosphorylation, is equally efficient in stimulating ATP synthesis in the wild type and A37. Malate-stimulated ATP synthesis in the wild type was shown to have many characteristics associated with oxidative phosphorylation and was absent in the mutant. These data suggest that the ATPase deficiency results in the loss of oxidative phosphorylation.

Adenosine Triphosphatases↗
PubMed1991

Substrate and pH effects on glutamine synthesis in rat liver. Consequences for acid-base regulation.

Switching in acidosis of hepatic nitrogen disposal from urea synthesis to NH4+ and net glutamine production was demonstrated in the isolated perfused livers of starved male Wistar rats. Lactate was preferred to glucose as the substrate for the carbon skeleton of glutamine synthesized over the pH range 6.9-7.5. This is necessary if the switch away from a proton-producing process (ureagenesis) in acidosis is to constitute an acid-base regulating system intrinsic to the liver. Glutamine balance shifted with pH from marked net uptake to small net output under acidotic conditions (pH 7.5-6.9), an effect due solely to a decrease in glutamine uptake. NH4+ uptake by the liver had a linear relationship with pH, being markedly decreased in acidosis because glutamine synthesis was insufficient to compensate for the decreased incorporation into urea. Animals rendered chronically acidotic showed a lower central venous plasma urea concentration and a raised NH4+ concentration, but their livers synthesized no more glutamine when perfused at an acidotic pH than did normal livers. We conclude that perivenous hepatocytes may not be efficient scavengers of NH4+ ions, which must be partly disposed of elsewhere by non-proton-generating pathways if inhibition of ureagenesis is to represent a hepatic acid-base regulating system.

Acid-Base Equilibrium↗