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Interregional free-trade of agricultural products is expected to transfer embodied (virtual) water from more to less water-productive regions. However, irrigation in semi-arid to arid regions may significantly push up agricultural productivity but cause local water scarcity. This may result in a puzzle: inter-regional trade may save overall water consumption but lead to more severe local water scarcity. An analogous puzzle may exist for farmland, for instance, trade may save farmland but not address farmland scarcity. To test the existence of these two important puzzles, we applied environmentally extended multi-regional input-output models to obtain the inter-regional virtual agricultural water and land transfer across 48 states of the conterminous U.S. and estimated their agricultural land and water footprints in 2017. Such a detailed analysis showed that while the land-abundant Midwestern states exported a sizable amount of virtual farmland to other densely populated areas and foreign nations, the water-stressed Western U.S. and Southwestern U.S. states, like California, Arizona, and New Mexico, exported considerable amounts of water-intensive crops such as fruits, vegetables and tree nuts to the Eastern U.S. and overseas, thus worsen the local water scarcity of those water scarce states. Our analysis highlights a critical dilemma inherent in an economic productivity-focused incentive regime: It frequently leads to increased withdrawal of scarce water. Therefore, resource scarcity rents need to be reflected in inter-regional trade with the support of local environmental policies. • Interstate trade mitigates coastal U.S. cropland scarcity but worsens water issues. • The Southwest states export significant virtual water via water-intensive crops. • Conflict between high economic productivity and water use exists in California. • Underpricing of water boosts farming of high-profit, water-intensive crops. • Policies needed for balancing land and water use, ensuring sustainable agriculture. [ABSTRACT FROM AUTHOR]

A low complexity unitary estimating signal parameter via rotational invariance techniques (ESPRIT) algorithm is presented for angle estimation in bistatic multiple-input-multiple-output (MIMO) radar. The devised algorithm only requires calculating two submatrices covariance matrix, which reduces the computation cost in comparison with subspace methods. Moreover, the signal subspace can be efficiently acquired by exploiting the NystrÖm method, which only needs O M N K 2 flops. Thus, the presented algorithm has an essentially diminished computational effort, especially useful when K ≪ M N , while it can achieve efficient angle estimation accuracy as well as the existing algorithms. Several theoretical analysis and simulation results are provided to demonstrate the usefulness of the proposed scheme. [ABSTRACT FROM AUTHOR]

Antibiotics play a key role in the prevention and treatment of bacterial diseases for human and animals. The widespread use of antibiotics results in bacterial exposure to the concentrations that are lower than the MIC (that is, sub-inhibitory concentration (sub-MIC)) in the environment, humans, and livestock, which can lead to antibiotic resistance. In this review, we focus on the impact of sub-MIC antibiotics in bacterial virulence. This paper summarized the known relationships between sub-MIC antibiotics in the environment and bacterial virulence. Together, considering the impact of sub-MIC antibiotics and their alternative products in the virulence of bacteria, it is helpful to the rational use of antibiotics and the development of antibiotic alternative products to provide new insights. Key points • Sub-MIC level antibiotics exist in the environment, humans, and livestock. • The review includes mechanisms of sub-MIC antibiotics in bacterial virulence. • New antibacterial strategies and agents are being a new way to weaken virulence. [ABSTRACT FROM AUTHOR]

Existing direction of arrival (DOA) estimation methods in multiple-input multiple-out (MIMO) radar systems will encounter the performance degradation in the cases of few snapshots, low signal-to-noise ratio (SNR), closely spaced targets, or strongly correlated sources. To improve it, this paper develops a new sparse representation-based DOA estimation method. The main contributions are as follows: i) we construct a new real-valued double weighted -norm minimisation model; ii) we derive an improved reduced-dimension technique to enhance estimation accuracy; and iii) we design optimal and sparse weights carefully to improve the corresponding estimation accuracy. Finally, the effectiveness and theoretical analysis of the presented approach are verified by extensive numerical simulations, which proves that the new algorithm performs well at low SNR and with a small number of snapshots as well as at the coherent source case. [ABSTRACT FROM AUTHOR]

• The regulation mechanism of LuxS/AI-2 system on fluoroquinolones resistance is uncertain. • LuxS/AI-2 system affects fluoroquinolones resistance in Streptococcus suis. • This regulation mechanism achieved by efflux pump SatAB. Increasing resistance to fluoroquinolones (FQs), such as norfloxacin and enrofloxacin, supports the need for the discovery of novel molecules and alternative approaches in antimicrobial therapy. Quorum sensing (QS) is a promising target for next-generation anti-infective agents designed to address the evolving drug resistance in bacterial pathogens. Given that the LuxS/autoinducer-2 (AI-2) quorum-sensing system regulates microbial group behaviors, we hypothesized that this system influences the FQ susceptibility in Streptococcus suis. It was found that a luxS mutant (Δ luxS) of S. suis possesses an increased susceptibility to FQs compared to the wild type strain. When grown in the presence of sub-MIC of antibiotics, the Δ luxS strain showed a significant decrease in growth rate and biofilm formation. These results suggest that the FQ resistance in S. suis could involve a signaling mechanism associated with the LuxS/AI-2 quorum-sensing system. HPLC (High Performance Liquid Chromatography) analyses showed a significant increase in the intracellular accumulation of enrofloxacin in the Δ luxS strain compared to the wild type strain. This increase was less pronounced in the presence of exogenous AI-2. Moreover, the expression of satA and satB genes was decreased in the Δ luxS strain. Exogenous AI-2 reversed the down-regulated gene expression observed in the Δ luxS strain. Our study brought strong evidence that the LuxS/AI-2 system in S. suis is involved in FQ susceptibility by regulating the efflux pump SatAB. LuxS is highly conserved among Gram-positive bacteria and may therefore represent a novel antimicrobial target for an alternative approach in antimicrobial therapy. [ABSTRACT FROM AUTHOR]

Polyamine oxidases (PAOs) have been identified in a wide variety of animals, as well as in fungi and plant. Generally, plant PAOs oxidize spermine (Spm), spermidine (Spd) and their acetylated derivatives, N 1 -acetylspermine (N 1 -Aspm) and N 1 -acetylspermidine (N 1 -Aspd), while yeast PAOs oxidize Spm, N 1 -Aspm and N 1 -Aspd, but not Spd. By contrast, two different enzymes, namely spermine oxidase (SMO) and acetylpolyamine oxidase (APAO), specifically catalyze the oxidation of Spm and N 1 -Aspm/N 1 -Aspd, respectively. However, our knowledge on the biochemical and structural characterization of PAOs remains rather limited, and their evolutionary history is still enigmatic. In this study, two amphioxus ( Branchiostoma japonicum ) PAO genes, named Bjpao1 and Bjpao2 , were cloned and characterized. Both Bjpao1 and Bjpao2 displayed distinct tissue-specific expression patterns. Notably, rBjPAO1 oxidized both spermine and spermidine, but not N 1 -acetylspermine, whereas rBjPAO2 oxidizes both spermidine and N 1 -acetylspermine, but not spermine. To understand structure-function relationship, the enzymatic activities of mutant BjPAOs that were generated by site-directed mutagenesis and expressed in E. coli were examined, The results indicate that the residues H64, K301 and T460 in rBjPAO1, and H69, K315 and T467 in rBjPAO2 were all involved in substrate binding and enzyme catalytic activity to some extent. Based on our results and those of others, a model depicting the divergent evolution and functional specialization of vertebrate SMO and APAO genes is proposed. [ABSTRACT FROM AUTHOR]

Interferometric synthetic aperture radar (InSAR) is an effective technology for generating high-precision digital elevation models (DEMs). However, the vertical accuracy of InSAR DEMs is limited by the contradiction between height measurement sensitivity and phase unwrapping reliability in terms of normal baseline length as well as data voids caused by layover or shadow effects. In order to alleviate these two unfavorable factors, in this study, a novel InSAR DEM fusion method with guided filter is developed and assessed with multiple bistatic TanDEM-X InSAR data pairs of different normal baselines acquired from different orbits. Unlike the widely used fusion method based on pixel-by-pixel weighted average, the guided-filter-based method incorporates local spatial context information into the fusion and can thus effectively alleviate the noise effect and automatically fill in data voids. As a result of the local edge-preserving capability of the guided filter, the proposed fusion method can preserve terrain details by maintaining gradient consistency and introducing terrain features as guidance image. Furthermore, the proposed fusion method is computationally efficient owing to the linear time complexity of guided filter. The experimental results show that the fused DEM with guided filter can depict terrain details well and smooth the "salt-and-pepper" noise and fill in almost all of the data voids. The root mean square error (RMSE) of the fused InSAR DEM with guided filter is lower than those of the weighted average fused InSAR DEM and the TanDEM-X DEM released by the German Aerospace Center (DLR), thus validating the effectiveness of the fusion method proposed in this study. [ABSTRACT FROM AUTHOR]

• metA deletion inhibits bacterial growth and type III secretion system virulence of Citrobacter rodentium and Salmonella enteritidis. • metA deletion causes severe defects in colonization and pathogenicity of bacterial pathogens during infection. • Blockage of bacterial methionine biosynthesis may be a novel antibacterial strategy. • α-Methyl-methionine is a potential candidate drug for antibacterial interventions by targeting the bacterial methionine biosynthesis pathway. Bacterial pathogens reprogramme their metabolic networks to support growth and establish infection at specific sites. Bacterial central metabolism has been considered attractive for developing antimicrobial drugs; however, most metabolic enzymes are conserved between humans and bacteria. This study found that blockade of methionine biosynthesis in Citrobacter rodentium and Salmonella enteritidis inhibited bacterial growth and activity of the type III secretion system, resulting in severe defects in colonization and pathogenicity. In addition, α-methyl-methionine was found to inhibit the activity of methionine biosynthetic enzyme MetA, and consequently reduce the virulence and pathogenicity of enteric pathogens. These findings highlight the crucial role of methionine in bacterial virulence, and describe a potential new drug target. [Display omitted] [ABSTRACT FROM AUTHOR]

Bacterial biofilms (BFs) are membrane-like structures formed by the secretion of extracellular polymeric substances (EPS) by bacteria. The formation of BFs contributes to bacterial survival and drug resistance. When bacteria proliferate, they produce secondary metabolites that act as signaling molecules in bacterial communities that regulate intracellular and cell-to-cell communication. This communication can directly affect the physiological behavior of bacteria, including the production and emission of light (bioluminescence), the expression of virulence factors, the resistance to antibiotics, and the shift between planktonic and biofilm lifestyles. We review the major signaling molecules that regulate BF formation, with a focus on quorum-sensing systems (QS), cyclic diguanylate (c-di-GMP), two-component systems (TCS), and small RNA (sRNA). Understanding these processes will lead to new approaches for treating chronic diseases and preventing bacterial resistance. [ABSTRACT FROM AUTHOR]

Abstract The pharmacokinetic profiles of florfenicol (FF) and florfenicol amine (FFA) following a single oral dose of FF at 10 mg·kg−1 body weight were compared in crucian carp reared at three different temperatures of fresh water. The concentrations of FF and FFA were determined simultaneously by high-performance liquid chromatography coupled with fluorescence detection, followed by compartmental analysis using a one-compartment open model. At water temperatures of 10 ± 0.5, 20 ± 0.5, and 25 ± 0.5 °C, the maximum concentration (C max) of FF was 2.435, 2.795, and 3.555 μg·mL−1, respectively, while that of FFA was 0.810, 0.945, and 1.063 μg·mL−1, respectively. The absorption half-life (t 1/2ka) of FF was 0.72, 0.73, and 0.70 h, and the elimination half-life (t 1/2kel) was 22.86 12.29, and 9.56 h, respectively. The volume of distribution per fraction absorbed (V d /F) for FF at water temperatures of 10, 20, and 25 °C was 3.67, 2.99, and 2.29 L·kg−1, respectively. For FFA, the formation half-life (t 1/2kf) was 2.13, 3.47, and 5.11 h, respectively, whereas the t 1/2kel was 27.79, 20.33, and 15.44 h at water temperatures of 10, 20, and 25 °C, respectively. At higher water temperatures, FF was absorbed and eliminated more quickly and was more extensively distributed than at lower water temperatures; in addition, the formation and elimination of FFA were faster at higher water temperatures. From the values of time > minimum inhibitory concentration (T > MIC) calculated in the current study at 10 °C, an oral dose of FF at 10 mg·kg−1 body weight administered at 48-h intervals would be sufficient for the treatment of bacterial infection with an MIC of ≤0.5 μg·mL−1, whereas a 24-h interval would be necessary at 20 and 25 °C to treat bacterial infections with the same MIC. Highlights • The plasma concentrations of florfenicol amine were reported for the first time in crucian carp. • The pharmacokinetic profiles of florfenicol and florfenicol amine in crucian carp were compared at three water temperatures. • The dosing regimens were obtained for florfenicol in crucian carp reared at three different water temperatures. [ABSTRACT FROM AUTHOR]

Abstract: The pharmacokinetic profiles of florfenicol (FF) or florfenicol amine (FFA) in crucian carp were compared at different water temperatures after single intramuscular administration of FF at 10 mg/kg bodyweight. The concentrations of FF and FFA were determined by a high‐performance liquid chromatography method, and then, the concentration versus time data were subjected to compartmental analysis using a one‐compartment open model. At the water temperatures of 10, 20, and 25°C, the peak concentrations (Cmaxs) of FF were 2.28, 2.29, and 2.34 μg/ml, respectively, while those of FFA were 0.42, 0.71, and 0.82 μg/ml, respectively. And the absorption half‐life (t1/2ka) of FF was 0.21, 0.19, and 0.21 hr, while the elimination half‐life (t1/2kel) was 31.66, 24.77, and 21.48 hr, respectively. For FFA, the formation half‐life (t1/2kf) was 3.85, 8.97, and 12.43 hr, while the t1/2kel was 58.34, 30.27, and 21.22 hr, respectively. The results presented here demonstrated that the water temperature had effects on the elimination of both FF and FFA and the formation of FFA. Based on the T > MIC values calculated here, to treat the infections of bacterial with MIC value ≤ 0.5 μg/ml, FF intramuscularly given at 10 mg/kg bodyweight with a 72‐hr interval is sufficient at the water temperature of 10°C, while the intervals of 60 and 48 hr were needed at 20 and 25°C, respectively. But to treat bacterial with higher MIC values, more FF or FF at 10 mg/kg BW but with shorter intervals should be intramuscularly given to the infected fish. [ABSTRACT FROM AUTHOR]

The stratification of cancer into subtypes that are significantly associated with clinical outcomes is beneficial for targeted prognosis and treatment. In this study, we integrated somatic mutation and gene expression data to identify clusters of patients. In contrast to previous studies, we constructed cancer-type-specific significant co-expression networks (SCNs) rather than using a fixed gene network across all cancers, such as the network-based stratification (NBS) method, which ignores cancer heterogeneity. For each type of cancer, the gene expression data were used to construct the SCN network, while the gene somatic mutation data were mapped onto the network, propagated, and used for further clustering. For the clustering, we adopted an improved network-regularized non-negative matrix factorization (netNMF) (netNMF_HC) for a more precise classification. We applied our method to various datasets, including ovarian cancer (OV), lung adenocarcinoma (LUAD) and uterine corpus endometrial carcinoma (UCEC) cohorts derived from the TCGA (The Cancer Genome Atlas) project. Based on the results, we evaluated the performance of our method to identify survival-relevant subtypes and further compared it to the NBS method, which adopts priori networks and netNMF algorithm. The proposed algorithm outperformed the NBS method in identifying informative cancer subtypes that were significantly associated with clinical outcomes in most cancer types we studied. In particular, our method identified survival-associated UCEC subtypes that were not identified by the NBS method. Our analysis indicated valid subtyping of patient could be applied by mutation data with cancer-type-specific SCNs and netNMF_HC for individual cancers because of specific cancer co-expression patterns and more precise clustering. [ABSTRACT FROM AUTHOR]