Berntsentyson7072

The mitotic activity of root apical meristem (RAM) is critical to primary root growth and development. Previous studies have identified the roles of ROOT GROWTH FACTOR 1 (RGF1), a peptide ligand, and its receptors, RGF1 INSENSITIVEs (RGIs), a clade of five leucine-rich-repeat receptor-like kinases, in promoting cell division in the RAM, which determines the primary root length. However, the downstream signaling components remain elusive. In this study, we identify a complete mitogen-activated protein kinase (MAPK or MPK) cascade, composed of YDA, MKK4/MKK5, and MPK3/MPK6, that functions downstream of the RGF1-RGI ligand-receptor pair. Similar to the rgi1/2/3/4/5 quintuple mutant, loss-of-function mutants of MPK3 and MPK6, MKK4 and MKK5, or YDA show a short-root phenotype, which is associated with reduced mitotic activity and lower expression of PLETHORA 1 (PLT1)/PLT2 in the RAM. Furthermore, MPK3/MPK6 activation in response to exogenous RGF1 treatment is impaired in the rgi1/2/3/4/5 quintuple, yda single, and mkk4 mkk5 double mutants. Epistatic analyses demonstrated that the expression of constitutively active MKK4, MKK5, or YDA driven by the RGI2 promoter can rescue the short-root phenotype of the rgi1/2/3/4/5 mutant. Taken together, these results suggest that the YDA-MKK4/MKK5-MPK3/MPK6 cascade functions downstream of the RGF1-RGI ligand-receptor pair and upstream of PLT1/PLT2 to modulate the stem cell population and primary root growth in Arabidopsis.Root growth is maintained by the continuous division of cells in the apical meristem. ROOT MERISTEM GROWTH FACTOR 1 (RGF1) is a critical peptide hormone regulating root stem cell niche maintenance. Previous studies discovered that five closely related leucine-rich repeat receptor-like protein kinases (LRR-RLKs), named RGF1 INSENSITIVES (RGIs) or RGF1 RECEPTORS (RGFRs), are able to perceive the RGF1 signal and redundantly control root stem cell niche maintenance. RGF1 regulates root meristem activity mainly via two downstream transcription factors, PLETHORA 1 (PLT1) and PLT2. Regulatory proteins connecting cell surface RGF1-RGI1 and nuclear PLTs, however, were not identified. Here, we report that the mitogen-activated protein (MAP) kinase kinase 4 (MKK4) and MAP kinase 3 (MPK3) were co-immunoprecipitated with RGI1-FLAG after Arabidopsis seedlings were treated with RGF1. Genetic and biochemical assays confirmed that MKK4 and MKK5, and their downstream targets MPK3 and MPK6, are essential RGI-dependent regulators of root meristem development. In addition, we found that the MKK4/MKK5-MPK3/MPK6 module functions downstream of YDA, a MAPKKK. Our results demonstrate that RGF1-RGI1 regulate the expression of PLT1/PLT2 via a YDA-MKK4/MKK5-MPK3/MPK6 signaling cascade.After three decades of the amazing progress made on molecular studies of plant-microbe interactions (MPMI), we have begun to ask ourselves "what are the major questions still remaining?" as if the puzzle has only a few pieces missing. Such an exercise has ultimately led to the realization that we still have many more questions than answers. Therefore, it would be an impossible task for us to project a coherent "big picture" of the MPMI field in a single review. Instead, we provide our opinions on where we would like to go in our research as an invitation to the community to join us in this exploration of new MPMI frontiers.

Regular and consistent parental involvement in children's oral hygiene practices is crucial to prevent oral diseases in young children. This emphasizes the need for interventions targeting parental-supervised oral hygiene behavior. To inform the design of future interventions, this meta-analysis aimed to identify the parental social-cognitive factors associated with oral hygiene behavior of preschoolers.

Five bibliographic databases were searched. A study was eligible for inclusion when it reported an association between a parental social-cognitive factor and an oral hygiene behavior in the targeted age cohort. see more Meta-analyses were performed when there were at least four independent effect sizes (k>3).

Of the 5945 records identified, 25 studies contained eligible data to be included in four meta-analyses attitude (k = 12); self-efficacy (k = 12); intention (k = 6), and sense of coherence (k=5). The results showed that greater frequency of preschoolers' oral hygiene behavior is significantly associated ntext. The significant social-cognitive correlates identified in this study, as well as potential other self-regulatory factors, should be targeted in future intervention studies aimed at improving this important preventive behavior.

The aim of this study was to identify Acinetobacter spp. strains from paediatric patients, to determine their genetic relationship, to detect antibiotic resistance genes and to evaluate the role of efflux pumps in antibiotic resistance.

A total of 54 non-duplicate, non-consecutive Acinetobacter spp. isolates were collected from paediatric patients. Their genetic relationship, antibiotic resistance profile, efflux pump activity, antibiotic resistance genes and plasmid profile were determined.

The isolates were identified as 24 Acinetobacter haemolyticus, 24 Acinetobacter calcoaceticus-baumannii (Acb) complex and 1 strain each of Acinetobacter junii, Acinetobacter radioresistens, Acinetobacter indicus, Acinetobacter lwoffii, Acinetobacter ursingii and Acinetobacter venetianus. The 24 A. haemolyticus were considered genetically unrelated. One strain was resistant to carbapenems, two to cephalosporins, two to ciprofloxacin and sixteen to aminoglycosides. The antibiotic resistance genes bla

(29%), bla

(4%), bla

(8%), bla

(29%), bla

(4%), aac(6')-Ig (38%) and the novel variants bla

(13%), bla

(75%), aac(6')-Iga (4%), aac(6')-Igb (13%) and aac(6')-Igc (42%) were detected. Among 24 Acb complex, 5 were multidrug-resistant, carbapenem-resistant strains carrying bla

and bla

 ; they were genetically related and had the same plasmid profile. Other species were susceptible. In some strains of A. haemolyticus and Acb complex, the role of RND efflux pumps was evidenced by a decrease in the MICs for cefotaxime, amikacin and ciprofloxacin in the presence of an efflux pump inhibitor.

This study identified isolates of A. haemolyticus carrying new β-lactamase variants and shows for the first time the contribution of efflux pumps to antibiotic resistance in this species.

This study identified isolates of A. haemolyticus carrying new β-lactamase variants and shows for the first time the contribution of efflux pumps to antibiotic resistance in this species.