Adaptive vegetation change as a pathway to sustain wetland nitrogen cycling

The purpose of this work is to establish the adaptive, stress and compensatory responses in people employed in titanium production and in laboratory animals kept at the Ust-Kamenogorsk Titanium and Magnesium Plant. It focused on the adaptive responses of mice (a total of 28 individuals in the experimental and control groups). The population of human participants consisted of 430 workers in the main workshops and 100 office workers (control group) employed at the plant. Morbidity and working conditions were analyzed. Urinary and blood biochemistry was evaluated. Changes in nitrogen metabolism were observed. The level of urea increased by 22%, creatinine – by 19%, and hydroxyproline – by 71% after a 2-week exposure to titanium and its compounds. Changes in carbohydrate metabolism were found. The level of glucose increased by 44% and the level of lactic acid increased by 65% after a 4- and 12-week exposure. As to animals, the study confirmed that there was a 41% increase in the concentration of lactic acid, a 38% increase in glucose, and a 50% increase in hydroxyproline following a 2-week exposure. Creatinine increased by 20%, indicating kidney damage in animals. The adaptive changes observed in workers can be markers in risk assessment. Keywords: Titanium, Pollution, Manufacturing plant, Toxins, Adaptive changes, Creatinine, Hydroproline

The biogeochemistry of N in freshwater wetlands is complicated by vegetation characteristics that range from annual herbs to perennial woodlands; by hydrologic characteristics that range from closed, precipitation-driven to tidal, riverine wetlands; and by the diversity of the nitrogen cycle itself. It is clear that sediments are the single largest pool of nitrogen in wetland ecosystems (100's to 1000's g N m-2) followed in rough order-of-magnitude decreases by plants and available inorganic nitrogen. Precipitation inputs (< 1–2 g N m-2 yr-1) are well known but other atmospheric inputs, e.g. dry deposition, are essentially unknown and could be as large or larger than wet deposition. Nitrogen fixation (acetylene reduction) is an important supplementary input in some wetlands (< < 1–3 g N m-2 yr-1) but is probably limited by the excess of fixed nitrogen usually present in wetland sediments. Plant uptake normally ranges from a few g N m-2 yr-1 to ∼ 35 g N m-2 yr-1 with extreme values of up to ∼ 100g N m-2 yr-1 Results of translocation experiments done to date may be misleading and may call for a reassessment of the magnitude of both plant uptake and leaching rates. Interactions between plant litter and decomposer microorganisms tend, over the short-term, to conserve nitrogen within the system in immobile forms. Later, decomposers release this nitrogen in forms and at rates that plants can efficiently reassimilate. The NO3 formed by nitrification (< 0.1 to 10 g N m-2 yr-1 has several fates which may tend to either conserve nitrogen (uptake and dissimilatory reduction to ammonium) or lead to its loss (denitrification). Both nitrification and denitrification operate at rates far below their potential and under proper conditions (e.g. draining or fluctuating water levels) may accelerate. However, virtually all estimates of denitrification rates in freshwater wetlands are based on measurements of potential denitrification, not actual denitrification and, as a consequence, the importance of denitrification in these ecosystems may have been greatly over estimated. In general, larger amounts of nitrogen cycle within freshwater wetlands than flow in or out. Except for closed, ombrotrophic systems this might seem an unusual characteristic for ecosystems that are dominated by the flux of water, however, two factors limit the opportunity for N loss. At any given time the fraction of nitrogen in wetlands that could be lost by hydrologic export is probably a small fraction of the potentially mineralizable nitrogen and is certainly a negligible fraction of the total nitrogen in the system. Second, in some cases freshwater wetlands may be hydrologically isolated so that the bulk of upland water flow may pass under (in the case of floating mats) or by (in the case of riparian systems) the biotically active components of the wetland. This may explain the rather limited range of N loading rates real wetlands can accept in comparison to, for example, percolation columns or engineered marshes.

Objetivo: identificar las respuestas del Sistema Socio-Ecológico (SSE) de la subcuenca baja Río Sonora ante distintas expresiones territoriales que marcan cada uno de los regímenes de aprovechamiento a partir de tres perspectivas: (a) escala ecológica, (b) alcance de las políticas de conservación y (c) contexto social. Metodología: descripción del contexto; identificación de la dinámica territorial a través de un Sistema de Información Geográfica, en un periodo de cuarenta años por medio de la técnica superposición geométrica de información vectorial. Resultados: interrelación territorial entre distintos vínculos productivos del SSE, alteración hidrológica, incremento sucesivo de usos de suelo y cambios de vegetación; se identifica el exiguo alcance de políticas de regulación ecológica; así como la tendencia demográfica decreciente en áreas rurales y niveles significativos de marginación. Limitaciones: se asume el margen de error de los insumos cartográficos oficiales. Conclusiones: las distintas perturbaciones por uso de suelo, la limitada regulación ecológica y el contexto demográfico del SSE generan una resiliencia cíclica y reducida, donde los cambios adaptativos se han traducido en una prolongación de la misma in/sustentabilidad de la subcuenca a través del tiempo.

ABSTRACTThe Lesser Khingan Mountains of north‐eastern China are heavily forested, making archaeological site identification difficult owing to poor ground surface visibility. Nevertheless, several prehistoric archaeological site discoveries have been made in recent years and a limited number of excavations have been initiated. One of the most important sites to emerge is Taoshan, which has yielded stratified stone tool assemblages dating from the Last Glacial Maximum (LGM) to the mid‐Holocene. Pollen profiles indicate significant changes in vegetation, fluctuating from steppe conditions during the LGM to forested conditions in the Bølling–Allerød interstadial (B–A) and the mid‐Holocene. The stone tool assemblages from Taoshan were primarily produced from varieties of volcanic tuff, rhyolite, hornfels and agate. Geological prospecting and petrological analyses were performed to document procurement sources and changes in raw material exploitation strategies. During the LGM, the predominant raw material was vitric tuff, available from a source ca. 5–10 km from Taoshan. In the B–A and mid‐Holocene layers, emphasis was on the exploitation of raw materials in gravel bars, although stone tool reduction techniques and raw material preferences changed considerably during this time interval. Diachronic changes in raw materials and exploitation strategies correspond to changes in vegetation and human adaptations.

The ruminal degradability, intake, and metabolism of diets differing in their relative rate of energy and nitrogen release in the rumen were characterized prior to their use in a study of the effects of high peripheral levels of ammonia on reproductive function in cattle. In a 2 x 2 factorial experiment, replicated four times, 16 heifers were offered isocaloric and isonitrogenous diets containing two sources of fermentable carbohydrate, fiber (slow energy release, SE) or starch (fast energy release, FE), and two rates of nitrogen release, which were either synchronous (S) or asynchronous (A) to that of energy release. Throughout the experiment, the amount of feed offered was held constant, at a level equivalent to 1.5 x maintenance. Four ruminally fistulated sheep were used to determine the in situ degradability of these diets. The 16 heifers were bled before feeding at 0800 and at 0900, 1000, 1100, 1200, 1400, and 1600 on d 0 (introduction to dietary treatments) and on d 4, 7, 11, 14, 21, and 28. Diet refusals were recorded at hourly intervals after feeding. The rapidly degradable nitrogen fraction of the SE:A and FE:A diets was greater than that of the SE:S and FE:S diets. Postprandial jugular plasma ammonia levels rose to a peak of around 300 micromol/L in heifers offered the SE:A and FE:A diets but did not rise in heifers offered the SE:S and FE:S diets. All feed offered was consumed within 1 h on diets SE:S and FE:S throughout the experiment. The proportion of feed consumed within 1 h of feeding declined from 100% on d 0 to around 70 and 56% by d 21 for heifers given the SE:A and FE:A diets, respectively. Peak postprandial plasma ammonia levels were accordingly lower, at around 160 micromol/L. Plasma urea levels averaged 7 mmol/L and were unaffected by dietary treatment. High plasma ammonia levels were associated with a suppression in the normal postprandial rise in insulin. There was no significant metabolic adaptation to high-ammonia-generating diets, and heifers given these diets modified their pattern of intake in an apparent attempt to avoid excessively high levels of plasma ammonia.

BackgroundNitrate and other nitrogen metabolites can act as signals that regulate global gene expression in plants. Adaptive changes in plant morphology and physiology triggered by changes in nitrate availability are partly explained by these changes in gene expression. Despite several genome-wide efforts to identify nitrate-regulated genes, no comprehensive study of the Arabidopsis root transcriptome under contrasting nitrate conditions has been carried out.ResultsIn this work, we employed the Illumina high throughput sequencing technology to perform an integrated analysis of the poly-A + enriched and the small RNA fractions of the Arabidopsis thaliana root transcriptome in response to nitrate treatments. Our sequencing strategy identified new nitrate-regulated genes including 40 genes not represented in the ATH1 Affymetrix GeneChip, a novel nitrate-responsive antisense transcript and a new nitrate responsive miRNA/TARGET module consisting of a novel microRNA, miR5640 and its target, AtPPC3.ConclusionsSequencing of small RNAs and mRNAs uncovered new genes, and enabled us to develop new hypotheses for nitrate regulation and coordination of carbon and nitrogen metabolism.

Grape pomace (GP), a by-product of winemaking, is rich in polyphenols and fiber, making it a promising and sustainable feed supplement for ruminants. This study evaluated the safety and productive impact of a 5% GP-supplemented diet (GP5) including non-lactating end-cycle (EC) ewes regularly destined for slaughter and human consumption, and lactating (LAC) ewes, over a 30-day period. Control (CTRL) animals received a standard pellet diet with no GP inclusion. Sampling was performed at four time points (T0, T10, T20, and T30), corresponding to days 0, 10, 20, and 30 of the experimental period. The study assessed clinical status, hematology/biochemistry (T0 and T30), milk composition (T0, T10, T20, and T30), meat quality traits and oxidative stability in EC ewes (T30). Since no significant differences were observed in the CTRL animals, the effects were evaluated within the GP5 group by comparing T0 vs. T30. Meat quality was assessed by comparing EC-GP5 to CTRL at T30. The GP extract showed a high total phenolic content (254.02 ± 20.39 mg GAE/g DW). No clinical or hematological alterations were observed, and most values remained within physiological ranges. Biochemical analysis revealed significant increases in albumin, bilirubin, creatinine, and triglycerides (p < 0.05), with significant decreases in plasma urea and glucose (p < 0.05). In LAC-GP5 ewes, milk urea and lactose concentrations decreased (p < 0.05), while pH increased (p < 0.05), with no significant changes in fat or casein content. These findings are consistent with reduced ruminal propionate availability, leading to decreased hepatic gluconeogenesis and lactose synthesis, with secondary effects on nitrogen metabolism and the acid–base profile of milk. In EC-GP5 ewes, meat quality traits were unaffected, and DPPH scavenging activity did not differ from CTRL (p > 0.05). GP5 was metabolically safe, induced adaptive changes in milk composition, and had no negative effects on meat quality, supporting the valorization of grape pomace as a sustainable feed resource. This trial was designed as a metabolic safety assessment, representing a preliminary step toward future mechanistic and molecular investigations.

Low light intensity is a major abiotic stress that severely affects rice yields, particularly in India and Southeast Asia, causing yield reductions of 35–40% during the wet season compared to the dry season. Tolerant rice genotypes exhibit adaptive changes at anatomical, physiological, biochemical, and molecular levels under low-light stress, enabling higher yields compared to susceptible varieties. Our study identified 20 novel QTLs associated with grain yields and nine related traits under low-light and control (normal)-light conditions, using a recombinant inbred line (RIL) population derived from the cross between the low-light-tolerant variety Swarnaprabha and the low-light-susceptible variety IR8. Across the Kharif seasons of 2019 and 2021, 33 stable QTLs were identified, with 11, 13, and 9 QTLs specific to low-light, normal-light, and both conditions, respectively. Of these, Swarnaprabha contributed 28 QTLs, while five were contributed by IR8. Notably, the study identified 11 and 9 novel QTLs under low-light and both conditions, respectively. Three hotspot regions on chromosomes 1, 4, and 8 were identified. These regions harbored 10 novel QTLs and revealed twenty candidate genes, out of which three key hub genes, OsAUX1, OsSBDCP1, and OsNPF5.16, were identified. These hub genes are involved in hormone signaling, starch metabolism, and nitrogen metabolism, respectively. A comprehensive expression analysis of these genes indicated that they are linked to low-light tolerance, offering deeper insights into the genetic and molecular mechanisms underlying low-light resilience. These findings provide valuable genomic resources and potential markers for breeding programs for improving rice productivity under low-light conditions.

To study the effect of dietary N level on urea kinetics and recycling, four Holstein heifers (267 +/- 3.6 kg) were used in a Youden square design. Isocaloric diets with a N content of 1.44, 1.89, 2.50, 2.97, and 3.40% were fed at approximately 1.8 times maintenance intake. Increasing the N content of the diet increased urinary N excretion (P < 0.001) and N balance (P < 0.01), but did not affect the fecal N excretion (P = 0.21). Increasing the level of dietary N, increased urea production (P < 0.001) and excretion (P < 0.001), but no effect (P = 0.24) could be detected in the amount of N recycled to the gut. Urea recycled with the saliva, however, increased (P < 0.001) both in absolute and relative terms, with increasing dietary N. No difference could be detected on the amount of recycled N that was used for anabolism or returned to the ornithine cycle, but less (P = 0.001) N originating from urea was excreted in feces as dietary N increased. Ruminal ammonia concentration increased (P < 0.001) with increasing N intake, but total tract neutral detergent fiber digestibility was depressed only on the lowest N intake diet. No difference (P = 0.30) was detected in ruminal microbial yield among diets, but more (P < 0.003) N was derived from blood urea at low N intakes, and the efficiency of use of the recycled N decreased (P < 0.001) with increasing levels of dietary N. Adaptive changes to low-N diets were a decrease (P < 0.003) in the renal clearance of urea and an increase (P < 0.001) in the gastrointestinal clearance of urea. Urea transporters were present in the rumen wall of the heifers and differentially expressed depending on dietary N content, but their role in the transfer of urea into the rumen remains uncertain. Different mechanisms of N salvage and recycling were involved when animals were fed low-N diets that ensured a supply of endogenous N to the gastrointestinal tract and, due to the reduced contribution of dietary N, an increased efficiency of the N recycled was observed.

The increasing demand for biopolymers has positioned poly-γ-glutamic acid (γ-PGA) as a promising alternative to fossil-based polymers due to its biodegradability and biocompatibility. γ-PGA biosynthesis in Bacillus subtilis is closely linked to intracellular glutamate availability, which is typically maintained via the supply of an exogenous glutamate source, a cost-intensive factor for industrial production. This study investigates the metabolic interplay between glycerol, citrate, and glutamate during γ-PGA synthesis, focusing on how cellular glutamate demand influences carbon source utilization. We demonstrate that reducing exogenous glutamate supply induces demand-driven co-consumption of glycerol and citrate, which is usually inhibited by carbon catabolite repression. In the absence of exogenous glutamate, the B. subtilis strain PG10 produced 8.4gL-1 γ-PGA, indicating significant de novo glutamate synthesis. A deletion analysis of known citrate transporters identified CimH as the key translocation system enabling citrate uptake under glutamate-limiting conditions. Further isotope labeling confirmed that citrate serves as a glutamate precursor during glutamate demand and is not used as a gluconeogenic substrate. Proteome analysis revealed a regulatory shift towards enhanced glutamate biosynthesis in the absence of exogenous glutamate, accompanied by reduced overflow metabolism and adaptive changes in central carbon and nitrogen metabolism. To our knowledge, carbon source co-utilization is a so far unknown response of B. subtilis 168 to glutamate scarcity. Uncovering the regulatory network involved offers a powerful tool by enabling biotechnological exploitation of this drastic change in carbon flux to boost the production of various products dependent on tricarboxylic acid cycle intermediates.

Proteomic analysis of post translational modifications in cyanobacteria

Wetlands are among the most productive life-support systems in the world and are of immense socio-economic and ecological importance to mankind. They are critical for the maintenance of biodiversity and perform a great role in the biosphere. Wetlands serve as a source, sink or transfer of nitrogen (N). The concentration, movement and transformation of nitrogen in wetland soil will significantly influence the structures and functions of wetland ecosystems. So study on nitrogen in wetland soils has significance to protect the environment. In this paper, the inputs, outputs and biogeochemical cycle of nitrogen in wetlands are introduced. The influence of wetland nitrogen cycle to the nature environmental change is also discussed.

Evidence for Younger Dryas global climate oscillation and human response in the American Southwest

Adaptive mechanisms of nitrogen and carbon assimilatory pathways in the marine cyanobacteria Prochlorococcus

The expression of drought responsive genes were enhanced by N application and they contributed to drought acclimation. The interactive effects of water and nutrient are crucial for plants. The aim of this study was to elucidate how nitrogen (N) status influence drought acclimation of Populus. A two-factorial design consisting of two N levels (adequate-N and low-N) and two watering treatments (drought stress and well-watered) was used, and an integrative investigation was conducted at the anatomical, physiological and molecular levels. Adequate N supply alleviated the adverse effects of drought stress on root growth in poplars, which may increase water uptake under drought. Nitrogen enhanced leaf anatomical changes and stomata adjustment upon drought stress, lead to less water losses and better growth performance under drought stress. The expression levels of phytohormone signaling components and genes responsible for antioxidative systems and secondary metabolites such as phenylpropanoids were promoted by N application. The expression of abscisic acid (ABA) signaling components was induced by drought when soil N was adequate, which participated in stomata regulation and drought acclimation. The expression of indole acetic acid (IAA) signaling components also was enhanced by N application, which participated in anatomical changes of leaves under drought. These adaptive changes at molecular and anatomical levels contributed to drought acclimation in a synergistic way. Under adequate-N condition, nitrogen and carbon metabolism pathways are being recruited to combat drought, and the C-N interaction play a pivotal role in drought acclimation.