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Genomic insights into extended- spectrum /3-lactamase- and plasmid-borne AmpC-producing Escherichia coli transmission between humans and livestock in rural Cambodia
Get PDFIntroduction. The global spread of extended- spectrum cephalosporinase- producing Escherichia coli (producing extended- spectrum /3- lactamase or plasmid-borne AmpC, hereafter ESC-Ec) is a major public health concern. Whilst extensively studied in high- income countries, the transmission pathways between humans and animals in low- and middle- income countries (LMICs) remain unclear. In rural Cambodia, the asymptomatic carriage and transmission dynamics of ESC-Ec between humans and animals living in close proximity are poorly understood, highlighting the need for targeted research in this area. Gap statement. An enhanced understanding of the genetic epidemiology of ESC-Ec can enable mitigation strategies to reduce the burden of disease and drug- resistant infections in LMIC settings. Aim. This study aimed to investigate the genetic relatedness and genotypic antibiotic resistance profiles of ESC-Ec strains from humans and livestock in rural Cambodia and to identify patterns of antimicrobial resistance (AMR) gene transmission between hosts and across households and villages. Methodology. Faecal samples were collected from 307 humans and 285 livestock in 100 households in or near Kampong Cham Province in rural Cambodia. From these samples, 108 ESC-Ec strains were subjected to whole- genome sequencing. Core genome MLST (cgMLST) and phylogenetic analysis determined genetic relationships between strains. All strains were screened for the presence of antibiotic resistance genes and plasmids. Results. Human and livestock isolates were assigned to six phylogroups, with phylogroup A being the most common (56.5%). MLST identified 50 sequence types (STs), 17 of which were shared between humans and animals, with ST155 being the most prevalent. cgMLST revealed 97 distinct cgMLST sequence types (cgST), indicating strain sharing between humans and animals. Additionally, AMR gene analysis showed widespread resistance, with genes from the blaCTX-M group detected in 84.2% of isolates. Notably, AMR genes such as aph(3")-Ib-sul2 co- occurred in 50% of isolates. Finally, plasmid analysis identified IncF plasmids in 75.9% of isolates, likely facilitating AMR gene transmission across hosts. Conclusions. Our findings demonstrate that ESC-Ec strains and their AMR genes are transmitted between humans and livestock in rural Cambodia, likely driven by both clonal spread and plasmid- mediated horizontal gene transfer. These results highlight the urgent need for antimicrobial stewardship and infection control strategies to mitigate the spread of multidrugresistant pathogens in both human and animal populations
ELF3 coordinates temperature and photoperiodic control of seasonal growth in hybrid aspen
Get PDFTimely growth cessation before winter is crucial for the survival of perennial plants in temperate and boreal regions. Short photoperiod (SP) and low temperature (LT) are major seasonal cues regulating growth cessation. SP, sensed in the leaves, initiates growth cessation by downregulating FLOWERING LOCUS T 2 (FT2) expression, but how LT regulates seasonal growth is unclear. Genetic and cell biological approaches identified a hybrid aspen EARLY FLOWERING 3(ELF3) ortholog with a prion-like domain (PrLD) that undergoes LT-responsive phase separation as a key mediator of LT-induced growth cessation. In contrast with SP, LT acts independently of FT2 downregulation and targets the AIL1-BRC1 transcription factor network and hormonal pathways via ELF3 to induce growth cessation. Intriguingly, ELF3 also functions in SP-mediated growth cessation by down-regulating FT2 in leaves. Our work thus reveals a previously unrecognized role of ELF3 in growth cessation and in coordinating temperature and photoperiodic pathways to enable robust adaptation to seasonal change
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Get PDFCarbon Emissions From Low-Order Streams in a Tropical, High-Elevation, Peatland Ecosystem Are Mediated by Catchment Morphology
Get PDFInland waters emit large amounts of carbon and are key players in the global carbon budget. Particularly high rates of carbon emissions have been reported in streams draining mountains, tropical regions, and peatlands. However, few studies have examined the spatial variability of CO2 concentrations and fluxes occurring within these systems, particularly as a function of catchment morphology. Here we evaluated spatial patterns of CO2 in three tropical, headwater catchments in relation to the river network and stream geomorphology. We measured dissolved carbon dioxide (pCO(2)), aquatic CO2 emissions, discharge, and stream depth and width at high spatial resolutions along multiple stream reaches. Confirming previous studies, we found that tropical headwater streams are an important source of CO2 to the atmosphere. More notably, we found marked, predictable spatial organization in aquatic carbon fluxes as a function of landscape position. For example, pCO(2) was consistently high (>10,000 ppm) at locations close to groundwater sources and just downstream of hydrologically connected wetlands, but consistently low (<1,000 ppm) in high gradient locations or river segments with larger drainage areas. Taken together, our findings suggest that catchment area and stream slope are important drivers of pCO(2) and gas transfer velocity (k) in mountainous streams, and as such they should be considered in catchment-scale assessments of CO2 emissions. Furthermore, our work suggests that accurate estimation of CO2 emissions requires understanding of dynamics across the entire stream network, from the smallest seeps to larger streams
Narrowing the ecological yield gap to sustain crop yields with less inputs
Get PDFSustainable production of sufficient and healthy food requires efficient use of agricultural inputs. In many regions of the world with intensive agriculture and relatively small yield gaps, this calls for a reduction of external inputs (fertilizers and pesticides) while maintaining yields. Ecological intensification, defined as the use of practices that enhance on-farm ecosystem services to reduce external input requirements, has been proposed as a strategy to help achieve this. However, the effects of ecological intensification are context- and input-dependent, creating uncertainty on its effectiveness and feasibility. Here, we introduce the concept of an 'ecological yield gap' to provide a common analytical framework to strengthen collaboration between agronomists and ecologists in assessing the contribution of ecosystem services within the wider array of inputs, management practices, technologies, and biophysical limits that determine on-farm crop yields. We define the ecological yield gap as the yield increase that could be achieved in a given context (climate x soil x cropping system), and at a given input level, by increasing the delivery of ecosystem services via ecological intensification practices that support crop growth and substitute external inputs. We provide empirical examples of such practices, including crop diversification, service crops, and organic amendments that can increase the use efficiency of mineral fertilizers and suppress pests, weeds and diseases. The potential of these practices to narrow the ecological yield gap and their feasibility at farm level depend on how the ecosystem services they provide interact with other aspects of the farming system and requires analysis at farm level. This perspective paper aims to facilitate a shared research agenda among agronomists and ecologists to develop complementarity between ecosystem services and inputs at field and farm levels
Chromotropism of Iron(II) Complexes with Non-Symmetric Heterocyclic Ligands: Polarity Sensing in Aqueous Urea Solutions
Get PDFThis study reports the synthesis and characterization of two solvatochromic pentacyanoferrate(II) complexes. Their structural design incorporates ligands with flexible xylylene bridges and distinct heterocycles-one combining 4-dimethylaminopyridine (DMAP) with 4,4 '-bipyridine, and the other isoquinoline with 4,4 '-bipyridine. Their structural diversity enables the complexes to engage in a broad range of solvent-solute interactions, providing valuable insights into the behavior of solvents and media with regard to polarity, through sizable solvatochromic shifts. Their solvatochromism is examined using a set of nine solvents and solvent mixtures. The solvatochromic sensitivities to polarity changes, expressed through a variety of polarity parameters and functions, are determined. Moreover, using a set of four complementary linear solvation energy relationships (LSERs), the roles of solvent polarity, solute-solvent interactions and the molecular responsiveness of the two compounds to different media are investigated. Additionally, their dipole moments in the ground and MLCT-excited states are determined using a suitable model, namely that of Suppan and Tsiamis. As a step further, the polarity sensing aptitude of the two solvatochromic compounds is examined in aqueous urea solutions at varying urea concentrations. The solvatochromic sensitivity of the two compounds is compared with that of a model cyanoferrate(II) complex, FeII(CN)2(phen)2. The two compounds clearly surpass the sensitivity of FeII(CN)2(phen)2 with subtle solvent polarity changes induced by varying the urea concentration. An LSER describing and predicting the solvatochromic effects in aqueous urea is developed and tested
Piloting an Information and Communication Technology Tool to Help Addressing the Challenge of Antimicrobial Resistance in Low-Income Countries
Get PDFBackground/Objectives: Antimicrobial use (AMU) in livestock drives antimicrobial resistance (AMR). AMR has a significant impact on public health. While several interventions have been used to address this challenge, few have utilized Information and Communication Technology (ICT) approaches. The objective of this study was to pilot and assess an ICT system to monitor the use of veterinary drugs and disseminate information to farmers in peri-urban smallholder poultry systems in Kenya. Methods: The system was developed in collaboration with the stakeholders. It captures drug sales in veterinary pharmacies and disease incidence and treatments reported by farmers. The system was piloted from May 2023 to December 2023. Monthly follow-ups were conducted to monitor progress and address problems. Assessment was performed through focus group discussions with the users (two with farmers and two with veterinary pharmacy staff) and descriptive statistics of the data collected by the system. Results: A total of 15,725 records were obtained from veterinary pharmacies, including antibiotics (57%), dewormers (22%), and vitamins (11%). Requests for a specific product were recorded in 38% of the sales, while 63% were accompanied by some evidence (empty drug containers, old packages, old prescriptions, pictures of sick birds, and actual sick birds). A total of 91 records were obtained from the farmers. The health problems reported were mostly respiratory (40%) and digestive (30%) disorders. The percentage of customers who requested advice on animal health when visiting veterinary pharmacies ranged from 5 to 20%. Conclusions: AMU can be improved in the study area. The piloted system may help policymakers monitor the sales and usage of antibiotics, improve animal health management, and promote responsible AMU
Limited Short-Term Effects of Tactile Stimulation on the Welfare of Newborn Nellore Calves
Get PDFThis study aimed to evaluate the effects of tactile stimulation on calf welfare. A total of 54 Nellore calves were assessed, with 28 of them receiving tactile stimulation (WTS) for similar to 60 s and 26 serving as a control. Five body movements and seven facial expressions were scored. Heart rates (HRs) were recorded in three situations: when the calves were placed in lateral recumbency (HR1), during identification procedures (HR2), and after completion of identification procedures (HR3). The differences between HR3 and HR1, as well as HR3 and HR2 were calculated. Initial and weaning weights were recorded, and ADG and weaning weights adjusted to 240 days were determined. Tactile stimulation significantly influenced "head movements", "third eyelid" exposure, "eye-opening", and "strained nostrils". Except for "strained nostrils", WTS calves exhibited higher scores in these behavioral categories. Treatment also influenced the difference between HR3 and HR2 (p 0.05). We conclude that tactile stimulation of newborn Nellore calves during their initial handling has the potential to enhance their short-term welfare, but only to a limited extent
Pearl millet WRKY transcription factor PgWRKY52 positively regulates salt stress tolerance through ABA-MeJA mediated transcriptional regulation
Get PDFEnvironmental stresses adversely affect plant growth and development by disturbing physiological and metabolic equilibrium. Plants counteract these stresses through intricate genetic and biochemical pathways, which are largely mediated by signalling networks that involve key transcription factors (TFs). Among these, WRKY TFs are crucial in modulating plant responses to various stresses. In previous studies, WRKY TFs have been identified in millets. However, their functional characterization in millets remains vastly unexplored. Therefore, we have isolated and characterized PgWRKY52, a Group IIc WRKY TFs from pearl millet, along with its upstream promoter region to understand its functional regulatory role. Ectopic expression of PgWRKY52 in transgenic Arabidopsis improved seed germination under salt stress and phytohormonal treatments of abscisic acid (ABA) and methyl jasmonate (MeJA). Improved stress tolerance was linked to reduced reactive oxygen species (ROS) accumulation and upregulation of stress-responsive genes, indicating an enhanced defense system. Promoter analysis unveiled that the PgWRKY52 promoter was constitutively active across vegetative and reproductive tissues, with strong stress-inducible activity under salt, heat, and ABA treatments. Cis-regulatory element (CRE) analysis identified key stress-responsive elements, including ABRE, MYB, W-box and MYC, which were validated through mutational studies as essential for promoter activity. Additionally, PgWRKY52 exhibited W-boxdependent DNA-binding capability, a characteristic feature of WRKY TFs. These findings emphasize the important function of the PgWRKY52 promoter in driving stress-responsive transcription. Altogether, these findings establish PgWRKY52 as a stress-responsive TF that enhances salt stress tolerance through crosstalk of ABA-MeJA signalling pathways and the regulatory role of its promoter, presenting a promising tool for developing climate-resilient crops