The effect of galactose metabolic disorders on rat brain Na+,K+-ATPase activity

To evaluate the effect of galactose metabolic disorders on the brain Na+,K+-ATPase in suckling rats. Separate preincubations of various concentrations (1-16 mM) of the compounds galactose-1-phosphate (Gal-1-P) and galactitol (galtol) with whole brain homogenates at 37 degrees C for 1 h resulted in a dose dependent inhibition of the enzyme whereas the pure enzyme (from porcine cerebral cortex) was stimulated. Glucose-1-phosphate (Glu-1-P) or galactose (Gal) stimulated both rat brain Na+,K+-ATPase and pure enzyme. A mixture of Gal-1-P (2 mM), galtol (2 mM) and Gal (4 mM), concentrations commonly found in untreated patients with classical galactosemia, caused a 35% (p < 0.001) rat brain enzyme inhibition. Additionally, incubation of a mixture of galtol (2 mM) and Gal (1 mM), which is usually observed in galactokinase deficient patients, resulted in a 25% (p < 0.001) brain enzyme inactivation. It is suggested that: a) The indirect inhibition of the brain Na+,K+-ATPase by Gal-1-P should be due to the presence of the epimer Gal and phosphate and that the pure enzyme direct activation by Gal-1-P and Glu-1-P to the presence of phosphate only. b) The observed brain Na+,K+-ATPase inhibitions in the presence of toxic concentrations of Gal-1-P and/or galtol could modulate the neural excitability, the metabolic energy production and the catecholaminergic and serotoninergic system.     

Alanine reverses the inhibitory effect of phenylalanine on acetylcholinesterase activity

The aim of this work was to evaluate, in vitro, the effect of L-alanine (Ala) on suckling rat brain acetylcholinesterase (AChE) and on eel Electrophorus electricus pure AChE inhibited by L-phenylalanine (Phe) as well as to investigate whether Phe or Ala is a competitive inhibitor or an effector of the enzyme. AChE activity was determined in brain homogenates and in the pure enzyme after 1 h preincubation with 1.2 mM of Phe or Ala as well as with Phe plus Ala. The activity of the pure AChE was also determined using as a substrate different amounts of acetylthiocholine. Ala reversed completely the inhibited AChE by Phe (18-20% in 500-600 microM substrate, p<0.01). Lineweaver-Burk plots showed that Vmax remained unchanged. However, Km was found increased with Phe (150%, p<0.001), decreased with Ala alone (50%, p<0.001) and unaltered with Phe plus Ala. It is suggested that: a) Phe presents a competitive inhibitory action with the substrate whereas Ala a competitive activation; b) Ala competition with Phe might unbind the latter from AChE molecule inducing the enzyme stimulation; c) Ala might reverse the inhibitory effect of Phe on brain AChE in phenylketonuric patients, if these results are extended into the in vivo reality.     

Simultaneous analysis of seven 16S rRNA hypervariable gene regions increases efficiency in marine bacterial diversity detection

Environmental DNA sequencing is the gold standard to reveal microbial community structures. In most applications, a one-fragment PCR approach is applied to amplify a taxonomic marker gene, usually a hypervariable region of the 16S rRNA gene. We used a new reverse complement (RC)-PCR-based assay that amplifies seven out of the nine hypervariable regions of the 16S rRNA gene, to interrogate bacterial communities in sediment samples collected from different coastal marine sites with an impact gradient. In parallel, we employed a traditional one-fragment analysis of the hypervariable V3–V4 region to investigate whether the RC-PCR reveals more of the ‘unseen’ diversity obtained by the one-fragment approach. As a benchmark for the full deck of diversity, we subjected the samples to PCR-free metagenomic sequencing. None of the two PCR-based approaches recorded the full taxonomic repertoire obtained from the metagenomics datasets. However, the RC-PCR approach detected 2.8 times more bacterial genera compared to the near-saturation sequenced V3–V4 samples. RC-PCR is an ideal compromise between the standard one-fragment approach and metagenomics sequencing and may guide future environmental sequencing studies, in which bacterial diversity is a central subject.     

DNA metabarcoding of airborne pollen: new protocols for improved taxonomic identification of environmental samples

Metabarcoding is a promising DNA-based method for identifying airborne pollen from environmental samples with advantages over microscopic methods. Sample preparation and DNA extraction are of fundamental importance for obtaining an optimal DNA yield. Currently, there is no standard procedure for these steps, especially for gravimetric pollen samplers. Therefore, the aim of this study was to develop protocols for processing environmental samples for pollen DNA extraction and for metabarcoding analysis and to assess the efficacy of these protocols for the taxonomic assignment of airborne pollen collected by gravimetric (Tauber trap) and volumetric (Hirst-type trap) samplers. Protocols were tested across an increasing complexity of samples, from pure single-species pollen to environmental multi-species samples. A short fragment (about 150 base pairs) of the chloroplast trnL gene was amplified using universal primers for plants. After PCR amplification, amplicons were Sanger-sequenced and taxonomic assignment was accomplished by comparison with a custom-made reference database including chloroplast DNA sequences from most of the anemophilous taxa occurring in the study area (Trentino, northern Italy), representing 46 plant families. Using the classical morphological pollen analysis as a benchmark, we show that DNA metabarcoding is efficient and applicable even in complex samples, provided that protocols for sample preparation, DNA extraction, and metabarcoding analysis are carefully optimized.     

Novel genetic risk variants for pediatric celiac disease

Background

Celiac disease is a complex chronic immune-mediated disorder of the small intestine. Today, the pathobiology of the disease is unclear, perplexing differential diagnosis, patient stratification, and decision-making in the clinic.

Methods

Herein, we adopted a next-generation sequencing approach in a celiac disease trio of Greek descent to identify all genomic variants with the potential of celiac disease predisposition.

Results

Analysis revealed six genomic variants of prime interest: SLC9A4 c.1919G>A, KIAA1109 c.2933T>C and c.4268_4269delCCinsTA, HoxB6 c.668C>A, HoxD12 c.418G>A, and NCK2 c.745_746delAAinsG, from which NCK2 c.745_746delAAinsG is novel. Data validation in pediatric celiac disease patients of Greek (n?=?109) and Serbian (n?=?73) descent and their healthy counterparts (n?=?111 and n?=?32, respectively) indicated that HoxD12 c.418G>A is more prevalent in celiac disease patients in the Serbian population (P?<?0.01), while NCK2 c.745_746delAAinsG is less prevalent in celiac disease patients rather than healthy individuals of Greek descent (P?=?0.03). SLC9A4 c.1919G>A and KIAA1109 c.2933T>C and c.4268_4269delCCinsTA were more abundant in patients; nevertheless, they failed to show statistical significance.

Conclusions

The next-generation sequencing-based family genomics approach described herein may serve as a paradigm towards the identification of novel functional variants with the aim of understanding complex disease pathobiology.

     

Serum copper and zinc concentrations in healthy children aged 3–14 years in greece

Zinc (Zn) and copper (Cu) are essential trace elements in people, being required for functional activity of several enzyme systems. In this study, we determined Cu and Zn concentrations in the serum of 105 healthy children randomly selected, aged 3–14 yr, residing in a region of Greece (Thrace), and we investigated their association with children's gender, age, height, weight, and nutritional habits. The mean levels of Zn and Cu were 15.01±2.95 μmol/L and 26.18±5.47 μmol/L, respectively, with no significant difference between boys and girls. A significant positive correlation was found between age and Zn levels, and a negative one was found between age and Cu levels. Both Zn and Cu levels tended to increase with height, whereas Zn levels significantly decreased with increasing body mass indent (BMI). The consumption of meat, milk, and eggs were independent determinants for higher Zn levels, and the consumption of legumes and fruits were independent determinants for higher Cu levels. A significant negative correlation was found between Zn and Cu levels. In conclusion, our study, the first one evaluating the serum status of Cu and Zn in healthy Greek children, identified significant correlations of Zn and Cu levels with their age, height, BMI, and nutritional habits.     

Production of 1,3-propanediol, 2,3-butanediol and ethanol by a newly isolated Klebsiella oxytoca strain growing on biodiesel-derived glycerol based media

The production of 1,3-propanediol, 2,3-butanediol and ethanol was studied, during cultivations of strain Klebsiella oxytoca FMCC-197 on biodiesel-derived glycerol based media. Different kinds of glycerol feedstocks and experimental conditions had an important impact upon the distribution of metabolic products; production of 1,3-propanediol was positively influenced by stable pH conditions and by the absence of N₂ gas infusions throughout the fermentation. Thus, during batch bioreactor fermentations conducted at increasing glycerol concentrations, 1,3-propanediol at 41.3 g/L and yield ～47% (w/w) was achieved at initial glycerol concentration ～120 g/L. At even higher initial glycerol media (150 and 170 g/L), growth was not ceased, but 1,3-propanediol production declined. During fed-batch fermentation under optimal experimental conditions, 126 g/L of glycerol were converted into 50.1 g/L of 1,3-propanediol. In this experiment, also 25.2 g/L of ethanol (conversion yield ～20%, w/w) were formed. A batch-bioreactor culture was performed under non-sterilized conditions and the 1,3-propanediol production was almost equivalent to the sterilized process. Concerning 2,3-butanediol formation, the most detrimental parameter was the absence of N₂ sparging and as a result, no 2,3-butanediol was produced. The presence of glucose as co-substrate seriously enhanced 2,3-butanediol production; when commercial glucose was employed as sole substrate, 32.1 g/L of 2,3-butanediol were formed.     

Active Inhibitor-1 Maintains Protein Hyper-Phosphorylation in Aging Hearts and Halts Remodeling in Failing Hearts

Impaired sarcoplasmic reticulum calcium cycling and depressed contractility are key characteristics in heart failure. Defects in sarcoplasmic reticulum function are characterized by decreased SERCA2a Ca-transport that is partially attributable to dephosphorylation of its regulator phospholamban by increased protein phosphatase 1 activity. Inhibition of protein phosphatase 1 through activation of its endogenous inhibitor-1 has been shown to enhance cardiac Ca-handling and contractility as well as protect from pathological stress remodeling in young mice. In this study, we assessed the long-term effects of inducible expression of constitutively active inhibitor-1 in the adult heart and followed function and remodeling through the aging process, up to 20 months. Mice with inhibitor-1 had normal survival and similar function to WTs. There was no overt remodeling as evidenced by measures of left ventricular end-systolic and diastolic diameters and posterior wall dimensions, heart weight to tibia length ratio, and histology. Higher phosphorylation of phospholamban at both Ser16 and Thr17 was maintained in aged hearts with active inhibitor-1, potentially offsetting the effects of elevated Ser2815-phosphorylation in ryanodine receptor, as there were no increases in arrhythmias under stress conditions in 20-month old mice. Furthermore, long-term expression of active inhibitor-1 via recombinant adeno-associated virus type 9 gene transfer in rats with pressure-overload induced heart failure improved function and prevented remodeling, associated with increased phosphorylation of phospholamban at Ser16 and Thr17. Thus, chronic inhibition of protein phosphatase 1, through increases in active inhibitor-1, does not accelerate age-related cardiomyopathy and gene transfer of this molecule in vivo improves function and halts remodeling in the long term.