Increased metabolite production by deletion of an HDA1-type histone deacetylase in the phytopathogenic fungi, Magnaporthe oryzae (Pyricularia oryzae) and Fusarium asiaticum

Histone deacetylases (HDACs) play an important role in the regulation of chromatin structure and gene expression. We found that dark pigmentation of Magnaporthe oryzae (anamorph Pyricularia oryzae) ΔMohda1, a mutant strain in which an orthologue of the yeast HDA1 was disrupted by double cross-over homologous recombination, was significantly stimulated in liquid culture. Analysis of metabolites in a ΔMohda1 mutant culture revealed that the accumulation of shunt products of the 1,8-dihydroxynaphthalene melanin and ergosterol pathways were significantly enhanced compared to the wild-type strain. Northern blot analysis of the ΔMohda1 mutant revealed transcriptional activation of three melanin genes that are dispersed throughout the genome of M. oryzae. The effect of deletion of the yeast HDA1 orthologue was also observed in Fusarium asiaticum from the Fusarium graminearum species complex; the HDF2 deletion mutant produced increased levels of nivalenol-type trichothecenes. These results suggest that histone modification via HDA1-type HDAC regulates the production of natural products in filamentous fungi.

SIGNIFICANCE AND IMPACT OF THE STUDY

Natural products of fungi have significant impacts on human welfare, in both detrimental and beneficial ways. Although HDA1-type histone deacetylase is not essential for vegetative growth, deletion of the gene affects the expression of clustered secondary metabolite genes in some fungi. Here, we report that such phenomena are also observed in physically unlinked genes required for melanin biosynthesis in the rice blast fungus. In addition, production of Fusarium trichothecenes, previously reported to be unaffected by HDA1 deletion, was significantly upregulated in another Fusarium species. Thus, the HDA1-inactivation strategy may be regarded as a general approach for overproduction and/or discovery of fungal metabolites.

Identification of novel BCL11A variants in patients with epileptic encephalopathy: Expanding the phenotypic spectrum

BCL11A encodes a zinc finger protein that is highly expressed in hematopoietic tissues and the brain, and that is known to function as a transcriptional repressor of fetal hemoglobin (HbF). Recently, de novo variants in BCL11A have been reported in individuals with intellectual disability syndrome without epilepsy. In this study, we performed whole-exome sequencing of 302 patients with epileptic encephalopathies (EEs), and identified 2 novel BCL11A variants, c.577delC (p.His193Metfs*3) and c.2351A>C (p.Lys784Thr). Both the patients shared major physical features characteristic of BCL11A-related intellectual disability syndrome, suggesting that characteristic physical features and the persistence of HbF should lead clinicians to suspect EEs caused by BCL11A pathogenic variants. Patient 1, with a frameshift variant, presented with Lennox-Gastaut syndrome, which expands the phenotypic spectrum of BCL11A haploinsufficiency. Patient 2, with a p.Lys784Thr variant, presented with West syndrome followed by drug-resistant focal seizures and more severe developmental disability. These 2 newly described patients contribute to delineating the associated, yet uncertain phenotypic characteristics of BCL11A disease-causing variants.

A motional Stark effect diagnostic analysis routine for improved resolution of iota in the core of the large helical device

A new Motional Stark Effect (MSE) analysis routine has been developed for improved spatial resolution in the core of the Large Helical Device (LHD). The routine was developed to reduce the dependency of the analysis on the Pfirsch-Schlüter (PS) current in the core. The technique used the change in the polarization angle as a function of flux in order to find the value of diota/dflux at each measurement location. By integrating inwards from the edge, the iota profile can be recovered from this method. This reduces the results' dependency on the PS current because the effect of the PS current on the MSE measurement is almost constant as a function of flux in the core; therefore, the uncertainty in the PS current has a minimal effect on the calculation of the iota profile. In addition, the VMEC database was remapped from flux into r/a space by interpolating in mode space in order to improve the database core resolution. These changes resulted in a much smoother iota profile, conforming more to the physics expectations of standard discharge scenarios in the core of the LHD.

Classical Spin Nematic Transition in LiGa_{0.95}In_{0.05}Cr_{4}O_{8}

We present the results of a combined ^{7}Li-NMR and diffraction study on LiGa_{0.95}In_{0.05}Cr_{4}O_{8}, a member of the LiGa_{1-x}In_{x}Cr_{4}O_{8} "breathing" pyrochlore family. Via specific heat and NMR measurements, we find that the complex sequence of first-order transitions observed for LiGaCr_{4}O_{8} is replaced by a single second-order transition at T_{f}=11  K. Neutron and x-ray diffraction rule out both structural symmetry lowering and magnetic long-range order as the origin of this transition. Instead, reverse Monte Carlo fitting of the magnetic diffuse scattering indicates that the low-temperature phase may be described as a collinear spin nematic state, characterized by a quadrupolar order parameter. This state also shows signs of short-range order between collinear spin arrangements on tetrahedra, revealed by mapping the reverse Monte Carlo spin configurations onto a three-state color model.

A baseline impedance analysis in neurologically impaired children: A potent parameter for estimating the condition of the esophageal mucosa

BACKGROUND

The aim of the present study was to investigate whether the baseline impedance (BI) value is a useful parameter to evaluate the condition of the esophageal mucosa in neurologically impaired (NI) children undergoing multichannel intraluminal impedance pH measurements (pH/MII).

METHODS

The retrospective study included 55 NI patients ≤15 years. The patients were divided into acid gastroesophageal reflux disease (GERD), non-acid GERD and GERD (-) groups. Furthermore, the patients in the acid GERD group were subdivided into erosive reflux disease (ERD) and non-erosive reflux disease (NERD) groups. pH/MII parameters and BI values (Z1-6) were compared among three groups or between two groups, respectively. A Spearman's correlation analysis was used for the correlation analysis of pH/MII parameters and BI values. A receiver operator characteristic curve analysis was used to evaluate the optimum cut-off values of BI to discriminate ERD patients.

KEY RESULTS

The BI values of the proximal and the distal channels in ERD group were significantly lower than those in NERD group. The BI values of the distal channels demonstrated significant negative correlations with acid exposure related pH/MII parameters. The optimal cut off value of BI in the most distal channel was determined to be 1500 Ω.

CONCLUSIONS & INFERENCES

The present study suggested that NI children with reflux esophagitis were likely to suffer mucosal damage up to the proximal esophagus and cut-off BI values may help estimate the presence of reflux esophagitis. Baseline impedance is a potent parameter, reflecting the esophageal mucosal damage in NI children who have difficulty in undergoing endoscopic examinations.