Effect Of Temperature Research Articles

Lorentz-violating Yukawa theory at finite temperature

This paper addresses Yukawa theory, focusing on the scattering between two identical fermions mediated by an intermediate scalar boson, considering the effects of thermal contributions and Lorentz symmetry breaking. Temperature is introduced into the theory through the thermofield dynamics formalism, while Lorentz violation arises from a background tensor coupled to the kinetic part of the Klein-Gordon Lagrangian. Two important quantities are calculated: the cross section for the scattering process and the modified Yukawa potential. The main results obtained in this work demonstrate that considering Lorentz symmetry breaking has several implications for changes in symmetries and physical states, while the presence of temperature is strongly related to the strength of the interaction. This interplay between symmetry breaking and temperature effects provides deeper insights into the behavior of the Yukawa theory under different conditions. Published by the American Physical Society 2024

Temperature and feeding frequency: interactions with growth, immune response, and water quality in juvenile Nile tilapia

Abstract Background Water temperature and feeding frequency are critical abiotic factors regulating the growth and immune function of aquatic organisms. This study investigated the effects of water temperature and feeding frequency on growth and immune function in Nile tilapia (Oreochromis niloticus) over two months. A total of 360 juvenile fish (average weight: 20.00 ± 1.26 g) were divided into six groups, each with three replicates, based on a combination of three water temperatures (26, 28, and 30 °C) and two feeding frequencies (either 1 or 2 meals per day). Results At 30 ºC and 28 ºC, water electrical conductivity and total dissolved salts increased, while total ammonia nitrogen and dissolved oxygen rose slightly in groups fed twice daily, with a significant interaction between temperature and feeding frequency. The group at 30 ºC with two meals per day showed the highest final body weight (FBW). The interaction between temperature and feeding frequency significantly influenced FBW, total feed intake, and body thickness. Fish at 30 ºC exhibited upregulated hepatic growth hormone receptor 1 and insulin-like growth factor 1, while those at 28 ºC with one meal per day, as well as those at 30 ºC regardless of meal frequency, also showed increased expression of hepatic fatty acid binding protein and intestinal cluster of differentiation 36. Fish at 30 ºC had upregulated leptin levels and downregulated cholecystokinin, while those at 26 ºC displayed the opposite trend, particularly with one meal daily. Higher temperatures significantly boosted serum IgM, superoxide dismutase (SOD), and lysozyme (LYZ) levels, with meal frequency also affecting malondialdehyde, IgM, and SOD levels. Additionally, 30 ºC enhanced the hepatic expression of mucin-like protein (muc), oligo-peptide transporter 1 (pept1), interleukin 1, nf-κB, complement C3, lyz, sod, catalase, and glutathione peroxidase, with twice-daily meals having a more pronounced effect. Conversely, 28 ºC with one meal per day upregulated some of these genes, such as muc, pept1, and sod. Conclusions Overall, 30 ºC with two meals per day significantly improved the growth and health of juvenile Nile tilapia, while 28 ºC with two meals maintained satisfactory performance.

Innovative modeling on the effects of low-temperature stress on rice yields

Abstract The increasing frequency and intensity of low-temperature events in temperate and cold rice production regions threaten rice yields under climate change. While process-based crop models can project climate impacts on rice yield, their accuracy under low-temperature conditions has not been well-evaluated. Our six-year chamber experiments revealed that low temperatures reduce spikelet fertility from panicle initiation to flowering, grain number per spike during panicle development, and grain weight during grain filling. We examined the algorithms of spikelet fertility response to temperature used in crop models. Results showed that simulation performance is poor for crop yields if the same function was used at different growth stages outside the booting stage. Indeed, we replaced a parameter spikelet fertility algorithm of the ORYZA model and developed the function of estimating grain number per spike and grain weight. After that, the improved equation algorithm was applied to 10 rice growth models. New functions considered the harmful effects of low temperatures on rice yield at different stages. In addition, the threshold temperatures of the cold tolerance were set for different rice varieties. The improved algorithm enhances the model's ability to simulate rice yields under climate change, providing a more reliable tool for adapting rice production to future climatic challenges.

Synthesis and characterization of titanium oxynitride catalyst via direct ammonia nitridation of titanium polyacrylate for oxygen reduction reaction

AbstractA titanium oxynitride catalyst for the oxygen reduction reaction (ORR) in polymer electrolyte fuel cells was synthesized through the direct ammonia nitridation of titanium complexes. Titanium polyacrylate was employed as the catalyst precursor, and the effect of the calcination temperature between 600 and 1000 °C on the catalyst structure was studied. The catalysts were characterized via X-ray diffraction, X-ray absorption spectroscopy, transmission electron microscopy, cyclic voltammetry, and powder electrical resistivity measurements. The formation of titanium oxynitride particles and deposited carbon was observed for all the samples; however, significant variations in the catalyst structure and catalytic activity were also observed. With an increase in the calcination temperature, nitridation of titanium oxynitride progressed, and the conductivity of the catalyst powder increased. The highest rest potential and ORR current density were achieved with calcination at 800 °C. Importantly, the results suggest that maintaining an optimal nitrogen doping level within the catalyst particles, along with ensuring the formation of electroconductive deposited carbon, is essential for achieving a high ORR current. This work introduces the direct ammonia nitridation of metal complexes as a promising process for designing metal oxynitride catalysts.

A Quasi Time-Domain Method for Fatigue Analysis of Reactor Pressure Vessels in Floating Nuclear Power Plants in Marine Environments

The reactor pressure vessel (RPV) in onshore nuclear power plants is typically analysed for fatigue life by considering the temperature, internal pressure, and seismic effects using a simplified time-domain fatigue analysis. In contrast, the frequency-domain fatigue analysis method is commonly employed to assess the fatigue life of ship structures. The RPV of a floating nuclear power plant (FNPP) is subjected to a combination of temperature, internal pressure, and wave loads in the marine environment. Consequently, it is essential to effectively integrate the frequency-domain fatigue analysis method used for hull structures with the time-domain fatigue analysis method for RPVs in FNPPs or, alternatively, to develop a suitable method that effectively accounts for the temperature, internal pressure, and wave loads. In this study, a quasi-time-domain method is proposed for the fatigue analysis of RPVs in FNPPs. In this method, secondary components of marine environmental loads are filtered out using principal component analysis. Subsequently, the stress spectrum induced by waves is transformed into a stress time history. Fatigue stress under the combined influence of temperature, internal pressure, and wave loads is then obtained through a stress component superposition method. Finally, the accuracy of the quasi-time-domain method was validated through three numerical examples. The results indicate that the calculated values obtained by the quasi-time-domain method are slightly higher than those obtained by the traditional time-domain method, with a maximum deviation of no more than 24%. Additionally, the computation time of the quasi-time-domain method is reduced by 98.67% compared to the traditional time-domain method.

Increasing thermostability of the key photorespiratory enzyme glycerate 3‐kinase by structure‐based recombination

SummaryAs global temperatures rise, improving crop yields will require enhancing the thermotolerance of crops. One approach for improving thermotolerance is using bioengineering to increase the thermostability of enzymes catalysing essential biological processes. Photorespiration is an essential recycling process in plants that is integral to photosynthesis and crop growth. The enzymes of photorespiration are targets for enhancing plant thermotolerance as this pathway limits carbon fixation at elevated temperatures. We explored the effects of temperature on the activity of the photorespiratory enzyme glycerate kinase (GLYK) from various organisms and the homologue from the thermophilic alga Cyanidioschyzon merolae was more thermotolerant than those from mesophilic plants, including Arabidopsis thaliana. To understand enzyme features underlying the thermotolerance of C. merolae GLYK (CmGLYK), we performed molecular dynamics simulations using AlphaFold‐predicted structures, which revealed greater movement of loop regions of mesophilic plant GLYKs at higher temperatures compared to CmGLYK. Based on these simulations, hybrid proteins were produced and analysed. These hybrid enzymes contained loop regions from CmGLYK replacing the most mobile corresponding loops of AtGLYK. Two of these hybrid enzymes had enhanced thermostability, with melting temperatures increased by 6 °C. One hybrid with three grafted loops maintained higher activity at elevated temperatures. Whilst this hybrid enzyme exhibited enhanced thermostability and a similar Km for ATP compared to AtGLYK, its Km for glycerate increased threefold. This study demonstrates that molecular dynamics simulation‐guided structure‐based recombination offers a promising strategy for enhancing the thermostability of other plant enzymes with possible application to increasing the thermotolerance of plants under warming climates.

Effects of Temperature, Dissolved Oxygen Concentration, and Photosynthetic Photon Flux Density on the Growth of the Sea Bivalve Tridacna crocea in Combination with the Symbiotic Alga Zooxanthella

The sea bivalve clam Tridacna crocea inhabiting the shallow sea of tropical and subtropical zones lives with the symbiotic alga zooxanthella in its mantle. Zooxanthellae algae perform photosynthesis and supply nutrients to T. crocea. Recently, the abundance of T. crocea has decreased rapidly due to overfishing in coastal areas in Okinawa, Japan. T. crocea culture systems for mass production will contribute to the conservation of T. crocea and thus marine ecosystems. Environmental control methods for T. crocea culture have not been established because of a lack of knowledge about the appropriate environmental conditions for T. crocea growth. The present study was initiated to obtain basic data for developing environmental control methods for T. crocea land-based aquaculture. The effects of water temperature, dissolved oxygen concentration, and photosynthetic photon flux density (PPFD) on the O2 exchange rates of the symbiotic system of T. crocea and zooxanthella, which are indicators of photosynthesis and respiration in the system, and the effect of daily integrated PPFD on T. crocea growth were investigated. Basic knowledge was obtained for the development of optimal environmental control technology for T. crocea clam culture. The optimum water temperature and dissolved oxygen concentration for photosynthesis in this symbiotic system were 28 °C, 5–6 mgO2 L−1 and 500 μmol m−2 d−1, respectively. The optimum daily integrated PPFD for clam growth was 20 mol m−2 d−1.

Effects of Fermentation Temperatures on the Qualities of Monascus sp. PSRU03 Fermented Soybeans

This research evaluated the effects of fermentation temperatures on the qualities of soybeans fermented with Monascus sp. PSRU03. The conditions included consistent temperatures of 25°C for 20 days, 30°C for 20 days, and a cyclic pattern of 30°C for 4 days followed by 25°C for 16 days. The pigments and antioxidant properties of the fermented soybeans were evaluated. After fermentation, it was observed that the total pigment contents exhibited similarity across all conditions, with values ranging from 31.90 to 35.67 unit/g dry basis. Notably, Monascus sp. PSRU03 produced more yellow pigment than other colors, accounting for approximately 50-53%, which corresponded to a range of 6.94-14.31 unit/g dry basis. This phenomenon is distinctive in that the majority of industrially manufactured Monascus pigments are rich in red pigments. In terms of antioxidant properties, fermentation at 30°C produced the highest total phenolic compounds (6.10 mg GAE/g dry basis). However, DPPH radical-scavenging activity and ferric reducing antioxidant power were found to be not significantly different (P≥0.05) in all fermentation temperatures. These findings provide a foundation for optimizing industrial fermentation processes and exploring the health benefits of Monascus-fermented soybeans.

The Effect of Fermentation and Storage Temperature on the Viability of Lactiplantibacillus plantarum subps. plantarum Dad-13 on Yogurt-Like Drink

This study aims to assess the viability of the cell population during the fermentation process and storage at various temperatures. Probiotic bacteria, Lactiplantibacillus plantarum subsp. plantarum Dad-13, procured from the Center for Food and Nutrition Studies UGM, was utilized as a starter in manufacturing a yogurt-like drink. During the manufacture of the yogurt-like drink, cell counts were evaluated prior to and following a 12-hour fermentation period at temperatures of 30 ℃, 37 ℃, and 42 °C. The samples that have the highest viability cell (30 °C) were selected for further study and stored for 25 days at 26 °C, and for 50 days at 10 °C and 4 °C. The cell count was assessed every 5 days using MRS Media.The result indicates that fermenting at 42 °C led to a notably lower cell growth rate of 0.2 log cycles compared to fermenting at 30 °C and 37 °C, leading to cell growth of 1.37 and 1.31 log cycles, respectively. The viability of Lactiplantibacillus plantarum subsp. plantarum Dad-13 in a yogurt-like drink was not significantly different after being stored for 50 days at temperatures of 10 °C and 4 °C. The decline in cell counts of Lactiplantibacillus plantarum subsp. plantarum Dad-13 in samples stored at 10 °C and 4 °C was 0.65 and 0.34 log cycles, respectively. Conversely, at 26 °C, the viability decreased significantly, resulting in a reduction in number of 2.05 log cycles.

Electrical Conductivity of (Mg, Fe)CO3 at the Spin Crossover and Its Implication for Mid‐Mantle Geomagnetic Heterogeneities

Abstract(Mg, Fe)CO3 is an important deep carbon carrier and plays a vital role in our understanding of lower‐mantle carbon reservoirs. The electrical conductivity (EC) of FeCO3 was measured at 126−2000 K up to 83 GPa in diamond‐anvil cells using a standard four‐probe van der Pauw method. Moreover, the EC of FeCO3 increases by ∼6 orders of magnitude from 300 to 1500 K at 10−20 GPa, indicating a strong effect of high temperature. The EC of Fe0.65Mg0.35CO3 was measured up to 60 GPa at 300 K, the EC values of (Mg, Fe)CO3 are proportional to iron content and increase by 2–3 orders of magnitude at 300 K across the spin crossover. The EC values of (Mg, Fe)CO3 and FeCO3 + Fe3O4 ± C mixtures surpass that of bridgmanite, ferropericlase and davemaoite by ∼1–4 orders of magnitude at depths of 800–2,000 km. This result sheds insights into the genesis of local geomagnetic heterogeneities in the mid‐lower mantle.

Physiological, morphological and chemical changes in pea seeds under different storage conditions.

The loss of germination, viability, and vigor of seeds under storage conditions are the main causes of the need to multiply the seed material for leguminous crops. For crop establishment, seeds obtained in propagation fields are usually used, and the coating comes from the basic seed. In the case of leguminous species, the seeds quickly lose their viability, and in accordance with international regulations, for legumes, the number of seeds increases only in the first year of propagation. Therefore, the main objective of this study was to assess the effects of variations in the storage period, temperature and humidity on the morphophysiological and chemical traits of two pea seed varieties (Gloriosa and Kelvedon Wonder). The pea seeds were harvested at the end of June 2017, 2018 and 2019 and stored for 32, 20 and 8months at T = 4°C and H = 8%; T = 4°C and H = 12%; T = 8°C and H = 8%; T = 8°C and H = 12%; and T = 22°C and H = 65%. The results of the morphological, chemical, and biochemical analyses showed that the highest germination rate; hypocotyl length; radicle length; lipid content; dietetic fiber content; caloric value; and Ca, Mg, K, Na, Fe and Zn contents were detected in the Gloriosa and KW seeds stored for 8months at 4°C and 8% humidity. Analysis of the experimental data by statistical methods revealed that increasing the storage time had an individual significant negative influence only on the germination rate of both pea varieties and on the hypocotyl length and radicle length of the KW variety, while humidity and temperature variation had individual significant influences on the lipid content. The significant effects of humidity and temperature on the germination rate, hypocotyl length and root length of KW plants were also determined. For the remaining morphophysiological and chemical traits of pea seeds, the individual and combined effects of the factors were not statistically significant. Furthermore, the comparison of means using the Tukey test showed that storage conditions related to temperature and humidity generally used by farmers (T = 22°C × H = 65%) did not significantly affect the majority of the nutritional properties of the pea seeds. However, maintaining pea seeds under these conditions for a longer period of time significantly affects seed germination and vigor.

Filtration Behaviour of Ostrea edulis: Diurnal Rhythmicity Influenced by Light Cycles, Body Size and Water Temperature

AbstractDespite the existing studies on oyster physiology, it is a concern that, by ignoring the diurnal rhythmicity of feeding activities, the current knowledge on oyster filtration might be unrepresentative of their real filtration capacity. In the present study, the diurnal and nocturnal fluctuations of Ostrea edulis clearance rate were investigated for the first time under laboratory conditions, also considering the combined effects of water temperature and oyster size. A positive correlation was found between the mean clearance rate (CRm) and body size for both length and wet weight, with an average of 0.5 L h−1 and 0.1 L h−1 of water filtered by large and small adult oysters respectively during the 24-h experiment. A positive significant correlation between mean clearance rate and water temperature was found only for large oysters, suggesting further studies utilising temperature ranges closer to O. edulis thermal optimum are required to clarify the influence of temperature on oyster filtration activities across different size classes. The results of this study also showed a discontinuous ingestion of food by O. edulis throughout 24-h intervals, with higher values of clearance rate observed during hours of darkness at most temperatures for both size classes. This suggests photoperiod may have a potential influence on O. edulis filtration. Providing a better understanding of O. edulis filtration behaviour, these findings have implications for ecological restoration, aquaculture, and comparative studies on oyster bioenergetics and physiology, with direct applications to the development of predictive models and the assessment of ecosystem services provided by O. edulis habitat.

Impact of Temperature and Shading on Performance of Solar Photovoltaic Systems in Telecom Sites

Nigeria's rural mobile network boom strains its power generation. Expensive and polluting diesel generators power off-grid base stations, prompting mobile network operators to explore solar PV systems. However, real-life performance under field conditions is a major concern, as manufacturer datasheets often fall short. This study highlighted the performance of a solar PV system powering a telecommunication station in Uli, Anambra State, Nigeria. We examined temperature, irradiance and shading effect. The findings highlight the impact of shading and temperature on energy yield and performance ratio (PR). While stand-alone and solar tracking systems had similar PRs (66 to 68 percent), tracking systems generated the most energy (4.53 energy yield) due to increased solar exposure. However, this benefit came with a trade-off; higher temperature losses (1559 kWh) caused by temperature rise from direct sunlight. Additionally, the nearby structures significantly impacted tracking systems by causing shading. In conclusion, well-designed solar PV systems for telecommunication stations must consider mitigating factors like shading and temperature. This can achieve substantial advantages: lower operational expenses for operators, improved network availability for rural users, and a reduced environmental impact, aligning with UN Sustainable Development Goals.

Novel SoC-Based FBG Calibration Method for Decoupled Temperature and Strain Analysis within LIB Cells

Abstract Internal temperature monitoring of battery cells can be very useful, as the core temperature can deviate significantly from that of the housing, especially in case of cells with a thick electrode stack. Conventional resistance temperature detectors can accurately measure temperature, but are limited to the outer surface of the cell due to induction effects. They are therefore not suitable for internal in situ measurements. Fiber Bragg grating (FBG) sensors are unaffected by the electric field as they operate by reflecting light. However, a specific difficulty is the distinction of temperature vs. strain effects as the grating is sensitive to both. In this work a calibration routine to separate the influences of temperature and strain in a lithium-ion battery cell is presented and examined for two multi-layer stack pouch cells (10 and 20 Ah). The obtained in situ temperature data reveal a difference of up to 2°C between center and cell housing at elevated discharge rate (4C) and a delay in detection of temperature peaks by the external sensor by 12 s. Strain data correlate with numbers of electrode layers in the stack and yield a stress of up to 27.3 MPa in the center of the 20 Ah cell.

Competing effects of temperature and mechanical stress on polar vortex transition in oxide superlattices

Competing effects of temperature and mechanical stress on polar vortex transition in oxide superlattices

Nonuniform Temperature Compensation in Ultrasonic Guided Wave Pipeline Health Monitoring Using Local Phase Matching

Faced with a complex working environment, pipelines are prone to nonuniform temperature variations, which cause nonuniform phase changes in the guided wave signals during structural health monitoring, thereby increasing the difficulty of monitoring. To address this, a simulation model is established in this paper to analyze the effects of temperature on material parameters and the variation patterns of guided wave signals. A nonuniform temperature compensation method based on local phase matching is proposed. The algorithm first uses cosine similarity to find the locally best-matched signal segments between the monitoring signal and the baseline signal. Then, an indicator is introduced to quantify the differences between these best-matched signal segments, with the maximum difference considered to be the damage index. Three heating experiments on pipelines with nonuniform temperature fields ranging from 24 °C to 80 °C demonstrate that the proposed method can effectively overcome the resulting phase deviations while achieving high detection accuracy and a reduction false positives. Additionally, the method shows high resolution in detecting defects in both temperature-varying and non-temperature-varying regions.

Thermal Quenching of Intrinsic Photoluminescence in Amorphous and Monoclinic HfO2 Nanotubes

Nanotubular hafnia arrays hold significant promise for advanced opto- and nanoelectronic applications. However, the known studies concern mostly the luminescent properties of doped HfO2-based nanostructures, while the optical properties of nominally pure hafnia with optically active centers of intrinsic origin are far from being sufficiently investigated. In this work, for the first time we have conducted research on the wide-range temperature effects in the photoluminescence processes of anion-defective hafnia nanotubes with an amorphous and monoclinic structure, synthesized by the electrochemical oxidation method. It is shown that the spectral parameters, such as the position of the maximum and half-width of the band, remain almost unchanged in the range of 7–296 K. The experimental data obtained for the photoluminescence temperature quenching are quantitatively analyzed under the assumption made for two independent channels of non-radiative relaxation of excitations with calculating the appropriate energies of activation barriers—9 and 39 meV for amorphous hafnia nanotubes, 15 and 141 meV for monoclinic ones. The similar temperature behavior of photoluminescence spectra indicates close values of short-range order parameters in the local atomic surrounding of the active emission centers in hafnium dioxide with amorphous and monoclinic structure. Anion vacancies VO− and VO2− appeared in the positions of three-coordinated oxygen and could be the main contributors to the spectral features of emission response and observed thermally stimulated processes. The recognized and clarified mechanisms occurring during thermal quenching of photoluminescence could be useful for the development of light-emitting devices and thermo-optical sensors with functional media based on oxygen-deficient hafnia nanotubes.

Effect of sintering temperature on color stability and translucency of various zirconia systems after immersion in coffee solution.

Achieving the aesthetic standards in tooth-colored restorative materials requires close attention to their color, translucency, and resistance to discoloration. This study aimed to evaluate the effect of sintering temperature on color stability and translucency in zirconia systems with low, high, and ultra-high translucencies. This experimental study was conducted on 60 zirconia disks with low, high and ultra-high translucencies (n = 20 per group), each group divided into subgroups to be sintered at either 1450°C or 1550°C (n = 10 per subgroup). Baseline color and translucency parameters were measured, the specimens were then immersed in coffee solution for 30 days, and the measurements were repeated post-immersion. Changes in color (ΔE) and translucency (ΔTP) were calculated via CIELAB formula and compared by using two-way ANOVA and Tukey's post hoc test (α = 0.05). Results of two-way ANOVA showed that the ΔE was significantly different among the three zirconia translucencies (P<0.001), but no significant difference was found between the two sintering temperatures (P = 0.712). Additionally, the interaction between zirconia type and sintering temperature was not statistically significant for ΔE (P = 0.264). The low-translucency group showed significantly greater ΔE than the high-translucency and ultra-high-translucency groups (P<0.05), while the high- and ultra-high-translucency groups were not significantly different in this regard (P>0.05). Regarding the ΔTP, two-way ANOVA showed that the difference was not statistically significant either among the three zirconia types (P = 0.4430) or between the two sintering temperatures (P = 0.4544). Nor was the interaction between zirconia type and sintering temperature statistically significant (P = 0.5505). It was concluded that sintering temperature had no effect on color and translucency changes after immersion in coffee. Whereas zirconia type significantly affected the color changes after immersion in coffee; with the higher-translucency zirconia types being significantly more color-stable than the low-translucency zirconia.

Effects of different water temperatures on the ovarian development and biochemical composition of Portunus trituberculatus after mating (Decapoda, Portunidae)

Abstract This study investigated the effects of different water temperatures (20, 23, 26 and 29°C) on the ovarian development and biochemical composition of Portunus trituberculatus (a swimming crab) after mating. The results showed that the higher the water temperature was, the faster the ovarian development, especially the GSI in the 29°C group was significantly higher than that in the 20°C and 23°C groups (). The hepatosomatic index (HSI) decreased with increasing water temperature, but there was no significant difference between the groups at different water temperatures (). The muscle yield (MY) was basically maintained at approximately 34%. The condition factor (CF) of the crab reached 0.62 in the 29°C group, which was significantly higher than that in the 20°C and 23°C groups (). Histological observation revealed that the number of lipid droplets and the degree of homogenization of yolk granules in ovarian oocytes gradually increased with the increase of the water temperature. From the perspective of conventional biochemical composition, the moisture and crude protein contents in muscle and the crude fat content in hepatopancreas did not change much among the groups, but the crude protein content in the ovary of the 29°C group was as high as 24.65%, which was significantly higher than that in the other three groups (). In terms of fatty acid composition, there was little difference in the fatty acid content in the ovaries of the different water temperature groups. The contents of C22 : 2n6 and C18 : 3n3 in polyunsaturated fatty acids were significantly higher in the 29°C group than in the other three groups (). In the hepatopancreas, the contents of C22 : 5n3 (DPA) and C22 : 6n3 (DHA) in the 20°C group were the lowest, 0.07% and 0.15%, respectively, which were significantly lower values than in the 29°C group (). The change of amino acid content is mainly reflected in ovarian tissues, showing a gradual upward trend as a whole. Furthermore, the essential amino acid score (EAAS) and average score of the two tissues in the 20°C and 23°C groups were relatively close, and both reached the highest score in the 29°C group. Overall, with increasing water temperature, the rate of ovarian development significantly accelerated, and the nutritional quality of the tissues improved in these swimming crabs.

Identification and biological characteristics of Fusarium tobaccum sp. nov., a novel species causing tobacco root rot in Jilin Province, China.

Fusarium wilt of tobacco (FWT), caused by Fusarium spp., has emerged as a severe threat to tobacco production in China. In all, 132 isolates of Fusarium were isolated from tobacco and pathogenic to tobacco-causing FWT in Jilin Province, China. In this study, we identified 7 of 132 isolates as a novel species Fusarium tobaccum sp. nov. Zhao Xie & Jie Gao, using multi-gene phylogenetic analyses of translation elongation factor (tef1), β-tubulin (tub2), calmodulin (cmdA), and RNA polymerase II second largest subunit (rpb2) genes, along with subtle morphological differences. Isolates of F. tobaccum sp. nov. were clustered in a distinct branch in the maximum parsimony phylogenetic tree generated from the sequences of tef1-rpb2-tub2-cmdA and can be distinguished from closely related species F. cugenangense, F. callistephi, and F. elaeidis. The morphological characteristics of F. tobaccum sp. nov. are distinct from other Fusarium species. F. tobaccum sp. nov. exhibits abundant aerial mycelia and pigment production on potato dextrose agar (PDA), microconidia with 0-1 septa, and macroconidia with 2-5 septa on carnation leaf-piece agar (CLA), and produces abundant chlamydospores on Spezieller Nährstoffarmer agar (SNA) and CLA. The mycelia of F. tobaccum exhibited optimal growth at a pH of 7.1 and a temperature of 23.6°C. Sucrose and NaNO3 significantly promoted the mycelial growth of F. tobaccum. PD medium was optimal for total sporulation. However, the sporulation ratios of the macrospores of F. tobaccum in PD, SN, and CMC were relatively low (0.48%, 2.51%, and 2.16%, respectively). These findings provided valuable insights into the morphological and biological characteristics of F. tobaccum.IMPORTANCEFusarium wilt of tobacco (FWT) is a prevalent issue in tobacco-growing regions globally, leading to significant losses in yield and quality. This study identified F. tobaccum sp. nov., a novel species of Fusarium causing FWT in China. The identification was based on multi-gene phylogenetic analyses and morphological characteristics. The effects of temperature, pH, carbon source, nitrogen source, medium, and light on the mycelial growth of F. tobaccum sp. nov. were determined. These findings might contribute to future research on the pathogenic mechanisms of this novel species and the development of strategies to control FWT.