Degree of methylation of ZAC1 (PLAGL1) is associated with prenatal and post-natal growth in healthy infants of the EDEN mother child cohort

The ZAC1 gene, mapped to the 6q24 region, is part of a network of co-regulated imprinted genes involved in the control of embryonic growth. Loss of methylation at the ZAC1 differentially methylated region (DMR) is associated with transient neonatal diabetes mellitus, a developmental disorder involving growth retardation and diabetes in the first weeks of post-natal life. We assessed whether the degree of methylation of the ZAC1 DMR in leukocytes DNA extracted from cord blood is associated with fetal, birth and post-natal anthropometric measures or with C-peptide concentrations in cord serum. We also searched for an influence of dietary intake and maternal parameters on ZAC1 DMR methylation. We found positive correlations between the ZAC1 DMR methylation index (MI) and estimated fetal weight (EFW) at 32 weeks of gestation, weight at birth and weight at one year of age (respectively, r = 0.15, 0.09, 0.14; P values = 0.01, 0.15, 0.03). However, there were no significant correlations between the ZAC1 DMR MI and cord blood C-peptide levels. Maternal intakes of alcohol and of vitamins B2 were positively correlated with ZAC1 DMR methylation (respectively, r = 0.2 and 0.14; P = 0.004 and 0.04). The influence of ZAC1 seems to start in the second half of pregnancy and continue at least until the first year of life. The maternal environment also appears to contribute to the regulation of DNA methylation.     

Topological studies on the enzymes catalyzing the biosynthesis of Glc-P- dolichol and the triglucosyl cap of Glc3Man9GlcNAc2-P-P-dolichol in microsomal vesicles from pig brain: use of the processing glucosidases I/II as latency markers

In the current model for Glc3Man9GlcNAc2-P-P-Dol assembly, Man5GlcNAc2- P-P-Dol, Man-P-Dol, and Glc-P-Dol are synthesized on the cytoplasmic face of the ER and diffuse transversely to the lumenal leaflet where the synthesis of the lipid-bound precursor oligosaccharide is completed. To establish the topological sites of Glc-P-Dol synthesis and the lipid-mediated glucosyltransfer reactions involved in Glc3Man9GlcNAc2-P-P-Dol synthesis in ER vesicles from pig brain, the trypsin-sensitivity of Glc-P-Dol synthase activity and the Glc-P- Dol:Glc0-2Man9GlcNAc2-P-P-Dol glucosyltransferases (GlcTases) was examined in sealed microsomal vesicles. Since ER vesicles from brain do not contain glucose 6-phosphate (Glc 6-P) phosphatase activity, the latency of the lumenally oriented, processing glucosidase I/II activities was used to assess the intactness of the vesicle preparations. Comparative enzymatic studies with sealed ER vesicles from brain and kidney, a tissue that contains Glc 6-P phosphatase, demonstrate the reliability of using the processing glucosidase activities as latency markers for topological studies with microsomal vesicles from non-gluconeogenic tissues lacking Glc 6-P phosphatase. The results obtained from the trypsin-sensitivity assays with sealed microsomal vesicles from brain are consistent with a topological model in which Glc-P-Dol is synthesized on the cytoplasmic face of the ER, and subsequently utilized by the three Glc-P-Dol-mediated GlcTases after "flip-flopping" to the lumenal monolayer.      

Species status of Neisseria gonorrhoeae: evolutionary and epidemiological inferences from multilocus sequence typing

Background  

Various typing methods have been developed for Neisseria gonorrhoeae, but none provide the combination of discrimination, reproducibility, portability, and genetic inference that allows the analysis of all aspects of the epidemiology of this pathogen from a single data set. Multilocus sequence typing (MLST) has been used successfully to characterize the related organisms Neisseria meningitidis and Neisseria lactamica. Here, the same seven locus Neisseria scheme was used to characterize a diverse collection of N. gonorrhoeae isolates to investigate whether this method would allow differentiation among isolates, and to distinguish these three species.     

Three-dimensional cancer cell culture in high-yield multiscale scaffolds by shear spinning

Polymeric scaffolds comprising two size scales of microfibers and submicron fibers can better support three-dimensional (3D) cell growth in tissue engineering, making them an important class of healthcare material. However, a major manufacturing barrier hampers their translation into wider practical use: scalability. Traditional production of two-scale scaffolds by electrospinning is slow and costly. For day-to-day cell cultures, the scaffolds need to be affordable, made in high yield to drive down cost. Combining expertise from academia and industry from the United Kingdom and United States, this study uses a new series of high-yield, low-cost scaffolds made by shear spinning for tissue engineering. The scaffolds comprise interwoven submicron fibers and microfibers throughout as observed under scanning electron microscopy and demonstrate good capability to support cell culturing for tumor modeling. Three model human cancer cell lines (HEK293, A549 and MCF-7) with stable expression of GFP were cultured in the scaffolds and found to exhibit efficient cell attachment and sustained 3D growth and proliferation for 30 days. Cryosection and multiphoton fluorescence microscopy confirmed the formation of compact 3D cell clusters throughout the scaffolds. In addition, comparative growth curves of 2D and 3D cultures show significant cell-type-dependent differences. This work applies high-yield shear-spun scaffolds in mammalian tissue engineering and brings practical, affordable applications of multiscale scaffolds closer to reality. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2750, 2019.     

Centrosome defects cause microcephaly by activating the 53BP1‐USP28‐TP53 mitotic surveillance pathway

Mutations in centrosome genes deplete neural progenitor cells (NPCs) during brain development, causing microcephaly. While NPC attrition is linked to TP53‐mediated cell death in several microcephaly models, how TP53 is activated remains unclear. In cultured cells, mitotic delays resulting from centrosome loss prevent the growth of unfit daughter cells by activating a pathway involving 53BP1, USP28, and TP53, termed the mitotic surveillance pathway. Whether this pathway is active in the developing brain is unknown. Here, we show that the depletion of centrosome proteins in NPCs prolongs mitosis and increases TP53‐mediated apoptosis. Cell death after a delayed mitosis was rescued by inactivation of the mitotic surveillance pathway. Moreover, 53BP1 or USP28 deletion restored NPC proliferation and brain size without correcting the upstream centrosome defects or extended mitosis. By contrast, microcephaly caused by the loss of the non‐centrosomal protein SMC5 is also TP53‐dependent but is not rescued by loss of 53BP1 or USP28. Thus, we propose that mutations in centrosome genes cause microcephaly by delaying mitosis and pathologically activating the mitotic surveillance pathway in the developing brain.     

Quirks of dye nomenclature. 7. Gentian violet and other violets

The name, gentian, appeared about 1880. Immediately following its discovery in 1861, this violet dye was known as Violet de Paris or as methyl violet. Initially used as a textile dye, it was soon used to color virtually anything. The names and identity of the components, the varying modes of manufacture, analytical methods and the dye’s significant contribution to biological staining are discussed here. Finally, I discuss the dye’s declining medical use following the revelation of its toxic nature.     

Crossfit analysis: a novel method to characterize the dynamics of induced plant responses

Background  

Many plant species show induced responses that protect them against exogenous attacks. These responses involve the production of many different bioactive compounds. Plant species belonging to the Brassicaceae family produce defensive glucosinolates, which may greatly influence their favorable nutritional properties for humans. Each responding compound may have its own dynamic profile and metabolic relationships with other compounds. The chemical background of the induced response is therefore highly complex and may therefore not reveal all the properties of the response in any single model.     

Classification-based comparison of pre-processing methods for interpretation of mass spectrometry generated clinical datasets

Background  

Mass spectrometry is increasingly being used to discover proteins or protein profiles associated with disease. Experimental design of mass-spectrometry studies has come under close scrutiny and the importance of strict protocols for sample collection is now understood. However, the question of how best to process the large quantities of data generated is still unanswered. Main challenges for the analysis are the choice of proper pre-processing and classification methods. While these two issues have been investigated in isolation, we propose to use the classification of patient samples as a clinically relevant benchmark for the evaluation of pre-processing methods.     

Belowground ABA boosts aboveground production of DIMBOA and primes induction of chlorogenic acid in maize

Plants are important mediators between above- and belowground herbivores. Consequently, interactions between root and shoot defenses can have far-reaching impacts on entire food webs. We recently reported that infestation of maize roots by larvae of the beetle Diabrotica virgifera virgifera induced shoot resistance against herbivores and pathogens. Root herbivory also enhanced aboveground DIMBOA and primed for enhanced induction of chlorogenic acid, two secondary metabolites that have been associated with plant stress resistance. Interestingly, the plant hormone abscisic acid (ABA) emerged as a putative long-distance signal in the regulation of these systemic defenses. In this addendum, we have investigated the role of root-derived ABA in aboveground regulation of DIMBOA and the phenolic compounds chlorogenic acid, caffeic and ferulic acid. Furthermore, we discuss the relevance of ABA in relation to defense against the leaf herbivore Spodoptera littoralis. Soil-drench treatment with ABA mimicked root herbivore-induced accumulation of DIMBOA in the leaves. Similarly, ABA mimicked aboveground priming of chlorogenic acid production, causing augmented induction of this compound after subsequent shoot attack by S. littoralis caterpillars. These findings confirm our notion that ABA acts as an important signal in the regulation of aboveground defenses during belowground herbivory. However, based on our previous finding that ABA alone is not sufficient to trigger aboveground resistance against S. littoralis caterpillars, our results also suggest that the ABA-inducible effects on DIMBOA and chlorogenic acid are not solely responsible for root herbivore-induced resistance against S. littoralis.Key words: induced resistance, Spodoptera littoralis, Zea mays, Diabrotica virgifera, DIMBOA, chlorogenic acid, absisic acid, priming     

mlstdbNet – distributed multi-locus sequence typing (MLST) databases

Background  

Multi-locus sequence typing (MLST) is a method of typing that facilitates the discrimination of microbial isolates by comparing the sequences of housekeeping gene fragments. The mlstdbNet software enables the implementation of distributed web-accessible MLST databases that can be linked widely over the Internet.