Acquisition of a novel conjugative multidrug-resistant hypervirulent plasmid leads to hypervirulence in clinical carbapenem-resistant Klebsiella pneumoniae strains

The co-occurrence of plasmid-mediated multidrug resistance and hypervirulence in epidemic carbapenem-resistant Klebsiella pneumoniae has emerged as a global public health issue.In this study,an ST23 carbapenem-resistant hyper-virulent K.pneumoniae(CR-HvKP)strain VH1-2 was identified from cucumber in China and harbored a novel hybrid plasmid pVH1-2-VIR.The plasmid pVH1-2-VIR carrying both virulence and multidrug-resistance(MDR)genes was likely generated through the recombination of a virulence plasmid and an IncFIIK conjugative MDR plasmid in clinical ST2318622 isolated from a sputum sample.The plasmid pVH1-2-VIR exhibited the capacity for transfer to the clinical ST11 carbapenem-resistant K.pneumoniae(CRKP)strain via conjugation assay.Acquisition of pVH1-2-VIR plasmid directly converted a CRKP into CR-HvKP strain characterized by hypermucoviscosity,heightened virulence for Galleria mellonella larvae,and increased colonization ability in the mouse intestine.The emergence of such a hybrid plasmid may expedite the spread of CR-HvKP strains,posing a significant risk to human health.

Modulation of nitrate-induced phosphate response by the MYB transcription factor RLI1/HINGE1 in the nucleus

The coordinated utilization of nitrogen(N)and phosphorus(P)is vital for plants to maintain nutrient balance and achieve optimal growth.Previously,we revealed a mechanism by which nitrate induces genes for phosphate utilization;this mechanism depends on NRT1.1B-facilitated degradation of cytoplasmic SPX4,which in turn promotes cytoplasmic-nuclear shuttling of PHR2,the central transcription factor of phosphate signaling,and triggers the nitrate-induced phosphate response(NIPR)and N-P coordinated utilization in rice.In this study,we unveiled a fine-tuning mechanism of NIPR in the nucleus regulated by Highly Induced by Nitrate Gene 1(HINGE1,also known as RLI1),a MYB-transcription factor closely related to PHR2.RLI1/HINGE1,which is transcriptionally activated by PHR2 under nitrate induction,can directly activate the expression of phosphate starvation-induced genes.More importantly,RLI1/HINGE1 competes with PHR2 for binding to its repressor proteins in the nucleus(SPX proteins),and consequently releases PHR2 to further enhance phosphate response.Therefore,RLI1/HINGE1 amplifies the phosphate response in the nucleus downstream of the cytoplasmic SPX4-PHR2 cascade,thereby enabling fine-tuning of N-P balance when nitrate supply is sufficient.

Responses of grazing households to different levels of payments for ecosystem services

Introduction:Payments for Ecosystem Services(PES)programs have been implemented globally to protect ecosystems while securing the well-being of affected people.Reasonable payment standards are key to successful PES programs.Although some approaches are available for determining payment standards,few studies have applied them for grassland conservation with location indicators and socioeconomic contexts properly considered.Methods:Using China’s first pilot Grassland Ecological Compensation Policy(GECP)as an example,we analyzed the effects of payment levels,other natural and socioeconomic factors on herders’willingness to participate in the GECP in Damao County in Inner Mongolia where grassland degradation is happening at an alarming rate due to overgrazing and cropland expansion.Outcomes:Our results show that households with lower herding income,older age,higher education,larger grassland areas,and worse social relationships are more inclined to participate in the GECP.Conservation payment level,as well as natural and socioeconomic contextual factors,significantly affect the response of herdsmen,and a reasonable grassland payment standard with a 95%policy compliance rate should be 8.8 yuan mu-1.Discussion and Conclusion:Our findings can inform governments to develop effective PES programs to balance the need of human well-being improvement and grassland conservation in China and beyond.