The p38 Pathway Regulates Oxidative Stress Tolerance by Phosphorylation of Mitochondrial Protein IscU

The p38 pathway is an evolutionarily conserved signaling pathway that responds to a variety of stresses. However, the underlying mechanisms are largely unknown. In the present study, we demonstrate that p38b is a major p38 MAPK involved in the regulation of oxidative stress tolerance in addition to p38a and p38c in Drosophila. We further show the importance of MK2 as a p38-activated downstream kinase in resistance to oxidative stresses. Furthermore, we identified the iron-sulfur cluster scaffold protein IscU as a new substrate of MK2 both in Drosophila cells and in mammalian cells. These results imply a new mechanistic connection between the p38 pathway and mitochondria iron-sulfur clusters.     

Dyskerin,tRNA genes,and condensin tether pericentric chromatin to the spindle axis in mitosis

Condensin is enriched in the pericentromere of budding yeast chromosomes where it is constrained to the spindle axis in metaphase. Pericentric condensin contributes to chromatin compaction, resistance to microtubule-based spindle forces, and spindle length and variance regulation. Condensin is clustered along the spindle axis in a heterogeneous fashion. We demonstrate that pericentric enrichment of condensin is mediated by interactions with transfer ribonucleic acid (tRNA) genes and their regulatory factors. This recruitment is important for generating axial tension on the pericentromere and coordinating movement between pericentromeres from different chromosomes. The interaction between condensin and tRNA genes in the pericentromere reveals a feature of yeast centromeres that has profound implications for the function and evolution of mitotic segregation mechanisms.     

Neurocognitive outcomes in Malawian children exposed to malaria during pregnancy: An observational birth cohort study

BackgroundAnnually 125 million pregnancies are at risk of malaria infection. However, the impact of exposure to malaria in pregnancy on neurodevelopment in children is not well understood. We hypothesized that malaria in pregnancy and associated maternal immune activation result in neurodevelopmental delay in exposed offspring.Methods and findingsBetween April 2014 and April 2015, we followed 421 Malawian mother–baby dyads (median [IQR] maternal age: 21 [19, 28] years) who were previously enrolled (median [IQR] gestational age at enrollment: 19.7 [17.9, 22.1] weeks) in a randomized controlled malaria prevention trial with 5 or 6 scheduled assessments of antenatal malaria infection by PCR. Children were evaluated at 12, 18, and/or 24 months of age with cognitive tests previously validated in Malawi: the Malawi Developmental Assessment Tool (MDAT) and the MacArthur–Bates Communicative Development Inventories (MCAB-CDI). We assessed the impact of antenatal malaria (n [%] positive: 240 [57.3]), placental malaria (n [%] positive: 112 [29.6]), and maternal immune activation on neurocognitive development in children. Linear mixed-effects analysis showed that children exposed to antenatal malaria between 33 and 37 weeks gestation had delayed language development across the 2-year follow-up, as measured by MCAB-CDI (adjusted beta estimate [95% CI], −7.53 [−13.04, −2.02], p = 0.008). Maternal immune activation, characterized by increased maternal sTNFRII concentration, between 33 and 37 weeks was associated with lower MCAB-CDI language score (adjusted beta estimate [95% CI], −8.57 [−13.09, −4.06], p < 0.001). Main limitations of this study include a relatively short length of follow-up and a potential for residual confounding that is characteristic of observational studies.ConclusionsThis mother–baby cohort presents evidence of a relationship between malaria in pregnancy and neurodevelopmental delay in offspring. Malaria in pregnancy may be a modifiable risk factor for neurodevelopmental injury independent of birth weight or prematurity. Successful interventions to prevent malaria during pregnancy may reduce the risk of neurocognitive delay in children.

Andrea Weckman and co-workers study associations between children’s neurodevelopmental outcomes and malaria in pregnancy.     

Effects of indoor culture conditions on growth and phycoerythrin content of Proteomonas sulcata (Cryptophyta) assessed by flow cytometry

Journal of Applied Phycology - The cryptophyte alga Proteomonas sulcata is rich in unsaturated fatty acids, phycoerythrin, and other biologically active substances and is suitable for aquatic feed,...     

A new genetic locus for self-compatibility in the outcrossing grass species perennial ryegrass (Lolium perenne)

BackgroundSelf-incompatibility (SI) is a physiological mechanism that many flowering plants employ to prevent self-fertilization and maintain heterozygosity. In the grass family this is known to be controlled by a two locus (S-Z) system; however, the SI system is intrinsically leaky. Modifier genes of both the S and Z loci and a further locus, T, are known to override SI leading to self-fertilization and self-seed production. This has implications for the ecological and evolutionary success as well as the commercial breeding of grasses. Here we report a study where the genetic control of self-compatibility (SC) was determined from the results of self-pollinating an F₂ population of perennial ryegrass from two independently derived inbred lines produced by single-seed descent.Methods In vitro self-pollinations of 73 fertile plants were analysed. A genetic association analysis was made with a panel of 1863 single-nucleotide polymorphism (SNP) markers, generated through genotype-by-sequencing methodology. Markers were placed on a recombination map of seven linkage groups (LGs) created using Joinmap v.5. The seed set on self- and open-pollinated inflorescences was determined on 143 plants, including the 73 plants analysed for self-pollination response.Key ResultsSelf-pollinations revealed a bimodal distribution of percentage SC with peaks at 50 and 100 %. A single quantitative trait locus (QTL) was identified with peak association for marker 6S14665z17875_11873 that mapped to LG 6. Peak position was associated with maximum marker segregation distortion. The self-compatible plants were equally fecund after self- and open pollination.ConclusionsThis is the first report in the Poaceae family of an SC locus located on LG 6. This new SC QTL discovery, as well as indicating the complex nature of the pollen–stigma recognition process and its evolutionary significance, provides an additional source of SC for breeding perennial ryegrass.     

The role of silk in courtship and chemical communication of the false widow spider, <Emphasis Type="Italic">Steatoda grossa</Emphasis> (Araneae: Theridiidae)

In spiders, sex pheromones are often associated with silk produced by females, and function in mate attraction, recognition, and evaluation. Silk-bound pheromones typically elicit courtship behaviour in web-building spiders. Here we (1) describe courtship interactions of Steatoda grossa males with virgin or mated females, and (2) show that silk and methanol extracts of silk produced by virgin females trigger courtship behaviour (silk production) by males, whereas silk of mated females does not. Our results indicate that (1) virgin females produce a silk-bound sex pheromone, (2) males discriminate between virgin and mated females based on silk cues, and (3) male silk likely functions in sexual communication.     

Lamin B1 and lamin B2 are long-lived proteins with distinct functions in retinal development

Lamin B1 and lamin B2 are essential building blocks of the nuclear lamina, a filamentous meshwork lining the nucleoplasmic side of the inner nuclear membrane. Deficiencies in lamin B1 and lamin B2 impair neurodevelopment, but distinct functions for the two proteins in the development and homeostasis of the CNS have been elusive. Here we show that embryonic depletion of lamin B1 in retinal progenitors and postmitotic neurons affects nuclear integrity, leads to the collapse of the laminB2 meshwork, impairs neuronal survival, and markedly reduces the cellularity of adult retinas. In stark contrast, a deficiency of lamin B2 in the embryonic retina has no obvious effect on lamin B1 localization or nuclear integrity in embryonic retinas, suggesting that lamin B1, but not lamin B2, is strictly required for nucleokinesis during embryonic neurogenesis. However, the absence of lamin B2 prevents proper lamination of adult retinal neurons, impairs synaptogenesis, and reduces cone photoreceptor survival. We also show that lamin B1 and lamin B2 are extremely long-lived proteins in rod and cone photoreceptors. OF interest, a complete absence of both proteins during postnatal life has little or no effect on the survival and function of cone photoreceptors.