In fungi, genes involved in biosynthesis of a secondary metabolite (SM) are often located adjacent to one another in the genome and are coordinately regulated. These SM biosynthetic gene clusters typically encode enzymes, one or more transcription factors, and a transport protein. Fusaric acid is a polyketide-derived SM produced by multiple species of the fungal genus Fusarium. This SM is of concern because it is toxic to animals and, therefore, is considered a mycotoxin and may contribute to plant pathogenesis. Preliminary descriptions of the fusaric acid (FA) biosynthetic gene (FUB) cluster have been reported in two Fusarium species, the maize pathogen F. verticillioides and the rice pathogen F. fujikuroi. The cluster consisted of five genes and did not include a transcription factor or transporter gene. Here, analysis of the FUB region in F. verticillioides, F. fujikuroi, and F. oxysporum, a plant pathogen with multiple hosts, indicates the FUB cluster consists of at least 12 genes (FUB1 to FUB12). Deletion analysis confirmed that nine FUB genes, including two Zn(II)2Cys6 transcription factor genes, are required for production of wild-type levels of FA. Comparisons of FUB cluster homologs across multiple Fusarium isolates and species revealed insertion of non-FUB genes at one or two locations in some homologs. Although the ability to produce FA contributed to the phytotoxicity of F. oxysporum culture extracts, lack of production did not affect virulence of F. oxysporum on cactus or F. verticillioides on maize seedlings. These findings provide new insights into the genetic and biochemical processes required for FA production.

SummaryGibberella zeae is an ascomyceteous fungus that causes serious diseases in cereal crops. Severe epidemics require strains that are virulent and that can reproduce sexually. We characterized an insertional mutant (designated ZH436) with a pleiotropic defect in both traits, and identified a novel F-box protein gene encoding FBP1 (F-box protein 1) that is similar to fungal F-box proteins including Saccharomyces cerevisiae Grr1, a well-characterized component of the Skp1-Cullin-F-box protein (SCF Grr1 ) E3 ligase complex required for protein degradation. FBP1 also can bind both S. cerevisiae Skp1 protein, the other component of the SCF Grr1 complex, and its G. zeae sequence homologue SKP1. Two putative protein interacting domains in FBP1 are essential for in vivo function. FBP1 and ScGRR1 are not so interchangeable between S. cerevisiae and G. zeae, but FBP1 can partially complement several defects of a yeast grr1 deletion mutant. Functional analyses confirmed that FBP1 is required for several phenotypes including both sexual development and virulence in G. zeae; the phenotype of DFBP1 strains is different from those of null mutants for F-box proteins in other filamentous fungi as well as from S. cerevisiae grr1D strains. Thus, FBP1 is a versatile F-box protein that presumably participates in the formation of the SCF FBP1 complex that probably controls the ubiquitin-mediated degradation of proteins involved in sexual reproduction and virulence important for disease development by G. zeae.

BackgroundProenkephalin (PENK) has been suggested as a novel biomarker for kidney function. We investigated the diagnostic and prognostic utility of plasma PENK in comparison with neutrophil gelatinase-associated lipocalin (NGAL) and estimated glomerular filtration rates (eGFR) in septic patients.MethodsA total of 167 septic patients were enrolled: 99 with sepsis, 37 with septic shock, and 31 with suspected sepsis. PENK and NGAL concentrations were measured and GFR was estimated by using the isotope dilution mass spectrometry traceable-Modification of Diet in Renal Disease (MDRD) Study and three Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations: CKD-EPICr, CDK-EPICysC, and CKD-EPICr-CysC. The PENK, NGAL, and eGFR results were compared according to sepsis severity, presence or absence of acute kidney injury (AKI), and clinical outcomes.ResultsThe PENK, NGAL, and eGFR results were significantly associated with sepsis severity and differed significantly between patients with and without AKI only in the sepsis group (all P<0.05). PENK was superior to NGAL in predicting AKI (P=0.022) and renal replacement therapy (RRT) (P=0.0085). Regardless of the variable GFR category by the different eGFR equations, PENK showed constant and significant associations with all eGFR equations. Unlike NGAL, PENK was not influenced by inflammation and predicted the 30-day mortality.ConclusionsPENK is a highly sensitive and objective biomarker of AKI and RRT and is useful for prognosis prediction in septic patients. With its diagnostic robustness and predictive power for survival, PENK constitutes a promising biomarker in critical care settings including sepsis.

ObjectivePresepsin is a novel biomarker to diagnose sepsis but its prognostic value has not been comprehensively reviewed. We conducted this meta-analysis to evaluate the mortality prediction value of presepsin in sepsis.MethodsWe searched comprehensive electronic databases from PubMed, EMBASE, and Cochrane Library through September 2017 using the key words of (‘presepsin’ or ‘sCD14-ST’ or ‘soluble CD14 subtype’) and (‘sepsis’ or ‘septic shock’) and (‘prognosis’ or ‘prognostic value’ or ‘prognostic biomarker’ or ‘mortality’). We extracted the presepsin levels in survivors and non-survivors from each individual study and evaluated the standardized mean difference (SMD) using a web-based meta-analysis with the R statistical analysis program.ResultsA total of 10 studies and 1617 patients were included. Presepsin levels in the first sampling (within 24 hours) were significantly lower among survivors as compared with non-survivors: the pooled SMD between survivors and non-survivors was 0.92 (95% CI: 0.62–1.22) in the random effects model (I2 = 79%, P< 0.01). In subgroups, divided by the sepsis severity or study site, pooled SMD was consistently noting higher presepsin levels in non-survivals (P< 0.05).ConclusionThis meta-analysis demonstrates some mortality prediction value in presepsin in patients with sepsis. Further studies are needed to define the optimal cut-off point to predict mortality in sepsis.

The glyoxylate and methylcitrate cycles are involved in the metabolism of two-or three-carbon compounds in fungi. To elucidate the role(s) of these pathways in Gibberella zeae, which causes head blight in cereal crops, we focused on the functions of G. zeae orthologs (GzICL1 and GzMCL1) of the genes that encode isocitrate lyase (ICL) and methylisocitrate lyase (MCL), respectively, key enzymes in each cycle. The deletion of GzICL1 (⌬GzICL1) caused defects in growth on acetate and in perithecium (sexual fruiting body) formation but not in virulence on barley and wheat, indicating that GzICL1 acts as the ICL of the glyoxylate cycle and is essential for self-fertility in G. zeae. In contrast, the ⌬GzMCL1 strains failed to grow on propionate but exhibited no major changes in other traits, suggesting that GzMCL1 is required for the methylcitrate cycle in G. zeae. Interestingly, double deletion of both GzICL1 and GzMCL1 caused significantly reduced virulence on host plants, indicating that both GzICL1 and GzMCL1 have redundant functions for plant infection in G. zeae. Thus, both GzICL1 and GzMCL1 may play important roles in determining major mycological and pathological traits of G. zeae by participating in different metabolic pathways for the use of fatty acids.