Search

[Display omitted] • Novel HN-AD bacterium, A. pittii J08, was isolated from pond sediments. • High removals of inorganic N and TN-N were analyzed in different N conditions. • Whole genome sequence and N metabolic pathways were analyzed. • Strain J08 showed a high adaptability to various culture conditions. A novel A. pittii J08 with heterotrophic nitrification and aerobic denitrification (HN-AD) isolated from pond sediments could rapidly degrade inorganic nitrogen (N) and total nitrogen (TN-N) with ammonium (NH 4 +-N) preference. N degradation rate of NH 4 +-N, nitrite (NO 2 −-N) and nitrate (NO 3 −-N) were 3.9 mgL−1h−1, 3.0 mgL−1h−1 and 2.7 mgL−1h−1, respectively. In addition, strain J08 could effectively utilize most of detected low-molecular-weight carbon (LMWC) sources to degrade inorganic N with a wide adaptability to various culture conditions. Whole genome sequencing (WGS) analysis revealed that assembled genome of stain J08 possessed the crucial genes involved in dissimilatory/assimilatory NO 3 −-N reduction and NH 4 +-N assimilation. These results indicated that strain J08 could be applied to wastewater treatment in aquaculture. [ABSTRACT FROM AUTHOR]

Fungal nodules and aged fungus gardens are products of termite fungiculture systems, and are the diets of termites. To understand the nutrition flow in fungiculture, we quantified the number and mass of fungal nodules produced along with fungus garden maturation and analysed the α-amino acid and fatty acid compositions of fungal nodules, fungus gardens, and termite tissues of a fungus-growing termite, Odontotermes formosanus. 1 g of fungus garden produced 5,148 fungal nodules (∼68.0 mg). Approximately 7.0% of α-amino acids were allocated to the fungal nodules and the rest (∼93.0%) remained in the fungus gardens. The compositions of α-amino acids or fatty acids in aged fungus gardens and fungal nodules were more similar to that of termite tissues than fresh fungus gardens, which supports the idea that termites nutritionally depend on the fungal products. Among the 18 α-amino acids, tryptophan was an essential amino acid and was the only one missing from fresh and aged fungus gardens, but found in fungal nodules at significantly higher concentrations. Hence, termites must consume fungal nodules to obtain tryptophan for survival. Furthermore, the fungus spores incorporated in nodules, were transferred when nodules were ingested by termites. We propose that allocating tryptophan in fungal nodules is crucial to enhance the mutualism between the fungus and termite. [ABSTRACT FROM AUTHOR]

Rice blast is one of the most devastating diseases that threatens rice production in Taiwan. A rice blast forecasting model is required to guide the precise application of fungicide. Therefore, BlastGRU-TW model based on deep learning algorithms was developed in this study. The input data comprised approximately 1000 rice blast surveys, collected from 50 fields throughout Taiwan between 2014 and 2021, and the corresponding weather data retrieved from weather observation network in Taiwan. Common and easily accessible meteorological factors, i.e. temperature, humidity, precipitation, and wind, were converted into 20 daily meteorological features which were coupled with different time intervals between 1 and 30 days before survey (DBS) to train the model. The results showed that seven meteorological features (daily maximum temperature, daily mean temperature, daily minimum temperature, daily mean humidity, daily mean WV and daily mean Wu) and the interval from −4 to −24 DBS were informative in disease prediction, thereby indicating that the proposed model could predict the risk of rice blast by using meteorological data 4–24 days before new disease symptoms appeared. The proposed BlastGRU-TW model achieved an accuracy of 87.3%. Furthermore, on adding the 3 day forecast weather data from Weather Research and Forecasting (WRF) model in the proposed model, the forecast extended to 7 days ahead of the appearance of new symptoms. Moreover, the BLASTAM model developed in Japan was implemented and validated in Taiwan to evaluate its applicability in different geographical areas. Finally, a rice blast early warning system (https://mycolab.pp.nchu.edu.tw/blast%5fforecast/index%5fen.php) equipped with an interactive web-based map is now available for real-time forecasting of the risk of rice blast in paddy field across Taiwan. • Input data from 1000 rice blast surveys in Taiwan for 2014–2021. • BlastGRU-TW model for deep learning-based rice blast prediction • The model achieves an accuracy of 87.3% • The BLASTAM model developed in Japan was the first to be implemented and validated outside Japan. • Forecast results can be visualized on a user-friendly, interactive web-based map. [ABSTRACT FROM AUTHOR]

N-alkanes distributions and stable isotopic compositions (δ 13C and δ 15N) in the lacustrine sediments of Shijiu lake were measured to assess whether biological source information was recorded in the molecular biomarker. Results showed regular unimodal n-alkanes distribution in range of C16–C33 with strong predominance of odd-numbered n-alkanes, maximizing at C29. The δ 15N for SON were uniformly low, ranging from −6.7‰ to 3.8‰ and C/N ratios ranged from 6.6 to 10.0, suggesting that most of organic matter was influenced by terrestrial characteristics of the watershed. The δ 13C for C27 to C31 n-alkanes and for SOC varied from −32.9‰ to −26.6‰ and −23.4‰ to −21.6‰, respectively, falling within the range of corresponding n-alkanes in leaves mainly from C3 land plants. The values of C/N, CPI, OEP, ACL and C27/C31 exhibit similar temporal changes with the primary production, showing enhanced eutrophication resulted from increased anthropogenic activities in Shijiu lake from 1852 to 2010. [Copyright &y& Elsevier]

Abstract: A series of mansonone F (MF) derivatives were designed and synthesized. These compounds were found to be strong inhibitors for topoisomerases, with much more significant inhibition for topoisomerase II rather than topoisomerase I. The best inhibitor showed 20 times stronger anti-topoisomerase II activity than a positive control Etoposide. The cytotoxic activity of these MF derivatives was evaluated against human cancer cell lines CNE-2 and Glc-82, which showed that these compounds were potent antitumor agents. The structure–activity relationships (SARs) study revealed that o-quinone group and pyran ring are important for their cytotoxic activity. [Copyright &y& Elsevier]

Aeromonas hydrophila can threaten the survival of freshwater fish. In this study, A. hydrophila challenge could induce tissue damage, promote antioxidant imbalance as well as alter the transcript levels of oxidative stress indicators, apoptotic genes and metabolic enzyme genes in kidney of red crucian carp (RCC). Metabolomics analysis revealed that A. hydrophila challenge had a profound effect on amino acid metabolism and lipid metabolism. In addition, we further identified dipeptides, fatty acid derivatives, cortisol, choline and tetrahydrocortisone as crucial biomarkers in kidney of RCC subjected to A. hydrophila infection. These results highlighted the importance of metabolic strategy against bacterial infection. [Display omitted] • Acute A. hydrophila infection could induce tissue damage in kidney of RCC. • Decreased level of antioxidant status was observed in kidney of RCC following A. hydrophila challenge. • hydrophila infection could decrease levels of dipeptides and fatty acid derivatives in kidney of RCC. [ABSTRACT FROM AUTHOR]

[Display omitted] • The SEA concentration curves are all sigmoid and consist of three phases. • The modified Gompertz model fits the curves of SEA concentration well. • Temperature and shaking can shorten the lag phase of SEA production. • Temperature and shaking can increase the rate and elevate the concentration of SEA. • The concentrations of S. aureus at the TTD range from 5.0 to 6.9 log CFU/mL. Numerous studies on bacterial growth or survival predictive models have been conducted since the establishment of predictive microbiology. However, limited research focused on the prediction of bacteria-producing enterotoxins, which are often the causative agents of food-borne diseases. This study aimed to determine an appropriate kinetic model of staphylococcal enterotoxin A (SEA) production in milk after contamination with Staphylococcus aureus. An S. aureus strain producing SEA was inoculated into milk with an initial inoculum concentration of approximately 3.0 log CFU/mL. All samples were incubated for 30–48 h at 20 °C ± 1 °C, 28 °C ± 1 °C, and 36 °C ± 1 °C separately under shaking or static conditions. Duplicate samples were carried out at appropriate intervals to count the number of S. aureus colonies and detect the concentration of SEA. Experimental results showed that the SEA concentration curves under all experimental conditions were sigmoidal and consisted of three phases: lag, exponential, and stationary. Thus, the modified Gompertz model was used to describe the profile of SEA concentration in milk during the incubation. A good fitting accuracy (R 2 > 0.97) indicated that the modified Gompertz model was appropriate. In addition to temperature, shaking during incubation also affected the maximal production rate of SEA and the maximal SEA concentrations, and shortened the lag phase at lower incubation temperatures, suggesting that the mechanical movements (e.g., stirring, pumping, and flowing) during the milk processing would increase the risk of SEA occurrence. Besides, the time to detection (TTD) of SEA was found to range from 3 to 24.5 h at temperatures of 36 °C ± 1 °C–20 °C ± 1 °C, at which time the concentrations of S. aureus ranging from 5.0 log CFU/mL–6.9 log CFU/mL at the TTD. This study contributed to understanding the kinetics of SEA production and the possible factors affecting the synthesis of SEA during the manufacturing of liquid foods, such as milk. [ABSTRACT FROM AUTHOR]

While aerosol plays a significant role in the formation of cloud, the in-cloud scavenging of chemically segregated particle types were still insufficiently investigated and the controlling factors remain ambiguous. Several field observations were carried out during 2018–2021 at Mt. Tianjing (1690 m a.s.l.) in southern China, based on ground-based counterflow virtual impactor (GCVI)-single particle aerosol mass spectrometer (SPAMS), to investigate the in-cloud scavenging (activation) of various particle types, including black carbon (BC), organic-containing particles (OC), mineral dust (Dust), metal-containing particles (Metal), potassium-rich particles (K-rich) and sea salt (SS). GCVI was used to sample cloud droplet residual particles (Res) while PM 2.5 inlet sampled interstitial particles (Inter) during cloud events and ambient particles (Amb) on sunny days, respectively. Different types of particles were recognized based on spectral characteristics obtained by the SPAMS. Based on the coupled GCVI-SPAMS measurements, the number-based scavenging efficiencies (NSEs) of various particle types could be quantified. Besides, the influence of liquid water content (LWC), PM 2.5 , particle size, and mixing state on the NSEs were discussed. The NSE of SS was the highest (32.4%) while OC showed the lowest NSE (9.1%). Other particle types shared similar NSEs with all the detected particles, with an average of ∼20–25%. Apart from OC, NSEs of other types of particles increased with the increase of LWC and decreased with the increase of the concentration of PM 2.5 , suggesting that numerous PM 2.5 suppressed particles entering cloud droplets via competing for water vapor. The annual variations of NSEs were generally in accordance with LWC and PM 2.5 , reflecting the certain role of these environment conditions. The NSEs typically increased with particle size in a range of 0.2–2.0 μm, reflecting the dominant nucleation mechanism during in-cloud scavenging. Particles mixed with sulfate and nitrate were easier to be scavenged than those coated with organic compounds, e.g., the discrepancy reached 11.8% for the K-rich particles. [Display omitted] • In-cloud scavenging efficiencies for six chemically segregated aerosol types are firstly reported. • SS displayed the highest NSE (32.4% on average) while OC's NSE was the lowest (9.1%). • The annual variations of NSEs were generally in accordance with LWC and PM 2.5 level. • Sulfate and nitrate enhance the NSEs of BC and K-rich particles by ∼10% compare with organics. [ABSTRACT FROM AUTHOR]

Aeromonas hydrophila can pose a great threat to fish survival. In this study, we investigated the differential immune and redox response in gut-liver axis of hybrid fish (WR) undergoing gut infection. WR anally intubated with A. hydrophila showed severe midgut injury with decreased length-to-width ratios of villi along with GC hyperplasia and enhanced antioxidant activities, but expression profiles of cytokines, chemokines, antibacterial molecules, redox sensors and tight junction proteins decreased dramatically. In contrast, immune-related gene expressions and antioxidant activities increased significantly in liver of WR following gut infection with A. hydrophila. These results highlighted the differential immune regulation and redox balance in gut-liver axis response to bacterial infection. [Display omitted] • Severe midgut injury with GC hyperplasia was observed in WR anally intubated with A. hydrophila. • Suppressions of tight junction molecules were observed in midgut of WR following gut infection. • WR receiving gut infection with A. hydrophila exhibited differential immune and redox response in gut-liver axis. [ABSTRACT FROM AUTHOR]

As a variant of peptide conantokin-T (con-T), con-T[M8Q] is derived from the venom of Conus tulipa . Our previous study has demonstrated that con-T[M8Q] selectively targets N -methyl- d -aspartate receptor (NMDAR) NR2B subunit. In the present study, we determined the effects of con-T[M8Q] on the expression and development of morphine tolerance using hot plate test and acetic acid writhing test. Our results demonstrated that con-T[M8Q] could efficiently attenuate the expression and development of morphine analgesic tolerance in mice at low doses (5–20 nmol/kg), and it exhibited more potent effects compared with ifenprodil, a typical small-molecule antagonist of NMDAR. In addition, low doses of con-T[M8Q] (5–20 nmol/kg) did not cause drug resistance and apparent analgesic activity compared with morphine. Taken together, con-T[M8Q] could be a promising new candidate in attenuating morphine tolerance. [ABSTRACT FROM AUTHOR]

Abstract: Expansion of food industry and international trade in foodstuffs, together with increasing worldwide attention to food safety heightened the need of exploring natural preservatives such as bacteriocins to prevent food contamination and spoilage. In this study, we uncovered a significant diversity of enterolysin A and helveticin J gene sequences belonging to bacteriolysins in popular Chinese traditional fermented foods using culture-independent metagenomic approach. The CODEHOPs targeting conserved motifs of the enterolysin A and helveticin J genes from Lactobacillales were designed to amplify respective gene sequences from six metagenomic DNA extracts by PCR. The amplicons were evaluated by sequence clone libraries and phylogenetic analyses. All translated enterolysin A sequences (77–80 amino acids) derived from four libraries were grouped into one cluster with 84–96% identity to homologs from Lactobacillus in GenBank database. Deduced helveticin J sequences (169–196 amino acids) derived from five libraries were classified into two distinct clusters, which shared 58–100% identity with public homologs in the database. Based on the obtained sequences, one of intact enlA and hlvJ genes was amplified by genome walking TAIL-PCR, and cloned into the expression vector pET-28a in Escherichia coli BL21, respectively. The recombinant EnlA (DFE5) producing a 30.6-kDa protein displayed antimicrobial activity against three bacterial genera, including human pathogens Listeria monocytogenes and Staphylococcus aureus. The expressed HlvJ (RS9) encoding a 249-aa protein was observed to inhibit Lactobacillus helveticus. This study demonstrated the validity of the metagenomic approach used in this study for identifying natural variants directly from complex food samples, but also provided the evidence that Chinese traditional fermented foods could be a valuable bacteriocin gene source for further exploration in food industry. [Copyright &y& Elsevier]

Abstract: In the present study, a series of novel azaoxoisoaporphine derivatives were reported and their inhibitory activities toward acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), and Aβ aggregation were evaluated. The new compounds remained high inhibitory potency on Aβ aggregation, with inhibitory activity from 29.42% to 89.63% at a concentration of 10μM, but had no action on AChE or BuChE, which was very different from our previously reported oxoaporphine and oxoisoaporphine derivatives. By 3D-QSAR studies, we constructed a reliable CoMFA model (q 2 =0.856 and r 2 =0.986) based on the inhibitory activities toward AChE and discovered key information on structure and anti-AChE activities among the azaoxoisoaporphine, oxoaporphine, and oxoisoaporphine derivatives. The model was further confirmed by the test-set validation (q 2 =0.873, r 2 =0.937, and slope k =0.902) and Y-randomization examination. The statistically significant and physically meaningful 3D-QSAR/CoMFA model provided better insight into understanding the inhibitory behaviors of those chemicals, which may provide useful information for the rational molecular design of azaoxoisoaporphine derivatives anti-AChE and anti-AD agents. [Copyright &y& Elsevier]

Abstract: Recently Thompson et al. (2006. A simple method for reducing seasonal bias and drift in eddy resolving ocean models. Ocean Modelling 13, 109–125.) proposed a new method for suppressing the bias and drift of ocean circulation models. The basic idea is to nudge the model toward gridded climatologies of observed temperature and salinity in prescribed frequency–wavenumber bands; outside of these bands the model''s dynamics are not directly affected by the nudging and the model state can evolve prognostically. Given the restriction of the nudging to certain frequency–wavenumber bands, the method is termed spectral nudging. The frequency–wavenumber bands are chosen to capture the information in the climatology and thus are centered on the climatological frequencies of zero, one cycle per year and its harmonics, and also low wavenumbers (reflecting the smooth nature of gridded climatologies). The new method is applied in this study to a fully nonlinear, 3D baroclinic circulation model of the continental shelves and inland seas of Atlantic Canada and the northeast US. It is shown that the scheme can suppress drift and bias in a nine month integration (February–October, 2002) while still allowing realistic evolution of tides, surges and wind and tide-driven coastal upwelling. It is also shown that density stratification can affect significantly tidal elevations in some regions. The implications for ocean hindcasting and short-term forecasting are discussed. [Copyright &y& Elsevier]

Over the past decade, secondary pollution characterized by active photochemistry has sharply increased and become the major contributor to air pollution in China, despite the great reduction of primary emissions. Peroxyacetyl nitrate (PAN) is an excellent indicator of photochemical pollution. Observation of PAN in high-elevation atmosphere offers a rare opportunity to understand the degree of photochemical activity in a wide region. In this study, we conducted a field campaign at a high-altitude (1690 m a.s.l.) national background site on the border of South and Central China during photochemically polluted seasons (Sep–Nov 2018). PAN showed significantly higher concentrations than other high-elevation sites worldwide, with hourly mean and maximum values of 0.52 ± 0.45 ppbv and 2.33 ppbv, respectively. Episodes with much higher PAN levels (1.03 ± 0.40 ppbv) than backgrounds (0.24 ± 0.13 ppbv) were captured. Nighttime peaks suggested mixed impacts of regional transport and VOCs oxidation by nitrate radical and O 3. High background O 3 (44.30 ± 0.44 ppbv) was derived from the significant positive correlation of O 3 with PAN. Contributions of downward transported PAN from upper troposphere were found to be non-negligible. Further analyses revealed that regional transport from Central China contributed substantially to the high levels of PAN, with only a minor contribution coming from the south where the Pearl River Delta (PRD) metropolitan region is located. Our results might indicate the great achievement in air quality improvement in the PRD, and also suggest that a strategic shift of control focus from metropolitan to developing areas is urgently needed for mitigating the severe photochemical pollution in China. [Display omitted] • First observations of PAN in the high-elevation background atmosphere of South-Central China. • Higher PAN concentrations than those at other high-elevation sites worldwide were observed. • Relatively high background O 3 was obtained from linear regression of O 3 and PAN. • Air masses coming from Central China significantly enhance the PAN levels. • Strategic shift of control focus from metropolitan to developing areas in China is suggested. [ABSTRACT FROM AUTHOR]

Five-year continuous O 3 measurements were conducted for the first time at the summit of Nanling Mountains (112.88° E, 24.68° N, 1690 m a.s.l), southern China in 2013–2017. Unlike most mountains over the world with O 3 maximum in spring or summer, Nanling showed O 3 maximum in mid-autumn (October; 62.8 ± 0.7 ppbv, ± 95% confidence intervals) and minimum in summer (July; 46.6 ± 0.7 ppbv). This distinct seasonal cycle of O 3 at Nanling was mainly caused by the special impact of Asian monsoon in southern China, which brought clean maritime background air and fresh emissions of the Pearl River Delta (PRD) region in spring/summer, and polluted northern continental air masses in autumn/winter, respectively. Further comparisons found that O 3 of Nanling in four seasons were all higher than other similar mountainous background sites, making the annual mean of O 3 (55.0 ± 0.2 ppbv) at Nanling the second highest that ever reported in the mountainous sites worldwide. Moreover, the diurnal variation showed the higher impact of regional transport during nighttime from the free troposphere (FT) and presented the potential air exchange between the FT and local atmosphere in the plenary boundary layer on the summit of Nanling. Both the seasonal variation and high O 3 level indicated a strong impact of anthropogenic emissions from alternatively PRD/northern China on O 3 pollution in this mountainous background region. This study diversifies the seasonal variations among mountains over the world, and also illustrates the complicated impact of anthropogenic emissions on the mountainous atmosphere in southern China. • The annual mean of O 3 (55 ± 18 ppbv) at Nanling was the second highest in the mountainous sites worldwide. • Different from others, Nanling showed O 3 maximum in mid-autumn and minimum in summer due to Asian monsoon. • Diurnal variations of O 3 at Nanling showed a minimum in the morning and a maximum at early night. [ABSTRACT FROM AUTHOR]

Interactions between clouds and black carbon (BC) represent a significant uncertainty in aerosol radiative forcing. To investigate the influence of cloud processing on the scavenging of BC, concurrent measurement of individual cloud droplet residue particles (cloud RES) and interstitial particles (cloud INT) throughout a cloud event was deployed at Mt. Tianjing (1690 m a.s.l.) in southern China. An aethalometer (AE-33), a single particle aerosol mass spectrometer (SPAMS) and a scanning mobility particle sizer (SMPS) were used to investigate the mass concentration of equivalent BC (EBC), size-resolved number of BC-containing particles, and size-resolved number concentration of submicron particles in real-time, respectively. The number-based SEs of the submicron particles varied between 2.7 and 31.1%. Mass scavenging efficiency (MSE) ranged from 4.7% to 52.6% for EBC, consistent with the number-based SE (from 11.3% to 59.6%) of the BC-containing particles throughout the cloud event. Several factors that may influence the SEs of the BC-containing particles are considered and examined. SEs are most likely determined by a single factor, i.e., liquid water content (LWC), with R2 > 0.8 in a power function throughout the cloud event. Stage-resolved investigation of SEs further reveals that particle size matters more than other factors in the cloud formation stage, whereas there is an increasing role of the mixing state in the development and stability stage. We also observed lower SEs for the BC-containing particles internally mixed organics, consistent with previous literature. • The stage-resolved scavenging efficiency of BC particles is firstly reported. • Scavenging efficiency (SE) is dominantly controlled by liquid water content (LWC). • Key factors influencing the in-cloud SE of BC-containing particles are assessed. [ABSTRACT FROM AUTHOR]

The formation mechanism of oxalate in the aqueous phase remains uncertain. Approximately 600 000 oxalate-containing particles and 450 000 its precursors-containing particles (e.g., acetate, glyoxylate, pyruvate and malonate) were obtained using a single particle aerosol mass spectrometer at a mountain site in southern China from 9 May to 4 June, 2018. The number fraction of oxalate or its precursors was compared within three representative aerosols with different liquid water contents including cloud droplet residues (RES), cloud interstitial particles (INTER) and cloud-free ambient particles (AMB). Lower number fraction of oxalate was found in the RES relative to INTER and AMB, mostly attributed to the decrease in precursors. This was conflicted with the enhancement of in-cloud oxalate formation previously reported. Further analysis indicated that the aerosol acidity had a major influence on the formation of precursors and their conversion to oxalate. With the increase of relative aerosol acidity (defined as the sum of sulfate and nitrate peak areas divided by ammonium peak area), the formation of precursors was increased while the conversion of precursors to oxalate was suppressed. Meanwhile, this influence was more pronounced in the INTER and AMB relative to RES. This work highlighted the roles of aerosol acidity and liquid water content in the aqueous phase formations of oxalate and its precursors. • Reduction of oxalate was found in cloud droplets residues relative to wet particles. • Enhanced relative aerosol acidity increased the formation of oxalate precursors. • Enhanced relative aerosol acidity suppressed the conversion of precursors to oxalate. [ABSTRACT FROM AUTHOR]