High Protein Diet Feeding Aggravates Hyperaminoacidemia in Mice Deficient in Proglucagon-Derived Peptides.

(1) Background: Protein stimulates the secretion of glucagon (GCG), which can affect glucose metabolism. This study aimed to analyze the metabolic effect of a high-protein diet (HPD) in the presence or absence of proglucagon-derived peptides, including GCG and GLP-1. (2) Methods: The response to HPD feeding for 7 days was analyzed in mice deficient in proglucagon-derived peptides (GCGKO). (3) Results: In both control and GCGKO mice, food intake and body weight decreased with HPD and intestinal expression of Pepck increased. HPD also decreased plasma FGF21 levels, regardless of the presence of proglucagon-derived peptides. In control mice, HPD increased the hepatic expression of enzymes involved in amino acid metabolism without the elevation of plasma amino acid levels, except branched-chain amino acids. On the other hand, HPD-induced changes in the hepatic gene expression were attenuated in GCGKO mice, resulting in marked hyperaminoacidemia with lower blood glucose levels; the plasma concentration of glutamine exceeded that of glucose in HPD-fed GCGKO mice. (4) Conclusions: Increased plasma amino acid levels are a common feature in animal models with blocked GCG activity, and our results underscore that GCG plays essential roles in the homeostasis of amino acid metabolism in response to altered protein intake.

SWI/SNF chromatin remodeling complex is required for initiation of sex-dependent differentiation in mouse germline.

Sexual reproduction involves the creation of sex-dependent gametes, oocytes and sperm. In mammals, sexually dimorphic differentiation commences in the primordial germ cells (PGCs) in embryonic gonads; PGCs in ovaries and testes differentiate into meiotic primary oocytes and mitotically quiescent prospermatogonia, respectively. Here, we show that the transition from PGCs to sex-specific germ cells was abrogated in conditional knockout mice carrying a null mutation of Smarcb1 (also known as Snf5) gene, which encodes a core subunit of the SWI/SNF chromatin remodeling complex. In female mutant mice, failure to upregulate meiosis-related genes resulted in impaired meiotic entry and progression, including defects in synapsis formation and DNA double strand break repair. Mutant male mice exhibited delayed mitotic arrest and DNA hypomethylation in retrotransposons and imprinted genes, resulting from aberrant expression of genes related to growth and de novo DNA methylation. Collectively, our results demonstrate that the SWI/SNF complex is required for transcriptional reprogramming in the initiation of sex-dependent differentiation of germ cells.

Amplicon sequencing analysis of arbuscular mycorrhizal fungal communities colonizing maize roots in different cover cropping and tillage systems.

Our understanding regarding the influence of intensive agricultural practices, including cover cropping and tillage, on communities of arbuscular mycorrhizal fungi (AMF) is lacking. This would prove to be an obstacle in the improvement of current maize (Zea mays L.) production. Therefore, using amplicon sequencing, we aimed to clarify how AMF communities and their diversity in maize roots vary under different cover cropping systems and two types of tillage (rotary and no tillage). Two kinds of cover crops (hairy vetch and brown mustard) and fallow treatments were established with rotary or no tillage in rotation with maize crops. Tillage and no tillage yielded a set of relatively common AMF operational taxonomic units (OTUs) in the maize crops, representing 78.3% of the total OTUs. The percentage of maize crop OTUs that were specific to only tillage and no tillage were 9.6% and 12.0%, respectively. We found that tillage system significantly altered the AMF communities in maize roots. However, the AMF communities of maize crops among cover cropping treatments did not vary considerably. Our findings indicate that compared with cover cropping, tillage may shape AMF communities in maize more strongly.

Neurochemistry evaluated by MR spectroscopy in a patient with xeroderma pigmentosum group A.

MRI of a female patient with xeroderma pigmentosum group A (XP-A) showed progressive cerebral atrophy, but no disease-specific lesion. MR spectroscopy with short TE sequences in the bilateral white matter revealed decreased N-acetyl aspartate (neuro-axonal marker) and increased myo-inositol (astroglial marker) with a normal concentration of choline (membrane marker), which are compatible with the neuropathology of XP-A, consisting of a reduced number of neurons, and fibrillary astrogliosis with preservation of myelinated fibers. MR spectroscopy reveals neurochemical derangement in XP-A, which cannot be observed on conventional MRI, and will be useful to monitor the neurochemical derangements of XP-A.

Female X-linked Alport syndrome with somatic mosaicism.

BACKGROUND: X-linked Alport syndrome (XLAS) is a progressive, hereditary nephropathy. Although males with XLAS usually develop end-stage renal disease before 30 years of age, some men show a milder phenotype and possess somatic mosaic variants of the type IV collagen α5 gene (COL4A5), with severity depending on variant frequencies. In females, somatic mosaic variants are rarely reported in XLAS, and it is not clear what determines severity. METHODS: Two females with somatic mosaic mutations in COL4A5 with variant frequencies of 17.9 and 22.1% were detected using the next-generation sequencing. One patient only had hematuria. The other, however, had moderate proteinuria, which is a severe phenotype for a female XLAS patient of her age. The molecular mechanisms for the severe phenotype were investigated by examining variant frequencies in urinary sediment cells and X chromosome inactivation patterns, and by looking for modifier variants in podocyte-related genes using the next-generation sequencing. RESULTS: The severe phenotype patient had a variant frequency of 36.6% in urinary sediment cells, which is not markedly high, nor did she show skewed X chromosome inactivation. However, she did have the heterozygous variant in COL4A3, which can affect severity. CONCLUSION: Factors determining severity in female XLAS patients remain unclear. One studied patient with the somatic variant in COL4A5 showed a severe phenotype without skewed X chromosome inactivation, which might be derived from digenic variants in COL4A3 and COL4A5. Further studies are required to determine molecular mechanisms behind female XLAS resulting in the severe phenotype.

Maternally administered melatonin protects against ischemia and reperfusion-induced oxidative mitochondrial damage in premature fetal rat brain.

We investigated the oxidative susceptibility of the brain and the effect of maternally administered melatonin on ischemia/reperfusion-induced cerebral damage in premature fetal rat. Fetal brain mitochondria was separated on the 16th and 19th days of pregnant rats and the respiratory control index (RCI) was measured as an indicator of mitochondrial respiratory activity in the presence or absence of xanthine and xanthine oxidase. The utero-ovarian arteries were occluded bilaterally for 20 min in female rats on day 16 of pregnancy to induce fetal ischemia. Reperfusion was achieved by releasing the occlusion and restoring circulation for 30 min. A sham operation was performed in control rats. Melatonin (10 mg/kg) or vehicle was injected intraperitoneally into the dams 60 min prior to occlusion. The RCI and concentration of thiobarbituric acid-reactive substances (TBARS) in fetal brain mitochondria were measured. The addition of xanthine and xanthine oxidase significantly decreased mitochondrial RCI at both the 16- and 19-day-old fetal brain. Xanthine and xanthine oxidase-induced reduction in RCI was significantly greater in the 16-day-old fetal brain than that in the fetal brain from the 19th day of pregnancy. Ischemia/reperfusion significantly reduced RCI and elevated TBARS concentrations in the 16-day-old fetal brain mitochondria. Melatonin treatment reversed ischemia/reperfusion-induced reduction in RCI (2.22 +/- 0.10 to 2.53 +/- 0.08, P < 0.01) and elevation in TBARS concentrations (13.50 +/- 1.82 nmol/mg protein to 8.80 +/- 0.78 nmol/mg protein, P < 0.01), resulting in values similar to those in untreated, sham-treated animals. Results indicate that brain mitochondria in the premature fetal rats appear to be more susceptible to oxidative damage. Melatonin administration to pregnant rats may prevent ischemia/reperfusion-induced oxidative mitochondrial damage in premature fetal brain.