Intensive fishing can mediate stronger size-dependent maternal effect in pike (Esox lucius)

In pike E. lucius L., evidence on maternal effect on reproductive output is mixed. We studied whether older and larger pike females produce eggs and larvae of higher quality (weight, starvation resistance) in three forest lakes in southern Finland. Later, the study lakes were subjected to intensive experimental pike fishing, which we assumed would increase resource availability and lead to higher maternal investment (larger egg size). Length of female pike was positively correlated with the dry weight of eggs and larvae but this relation was dependent on female age. In old females, the effect of female length on egg weight was lower or even negative. Survival analysis showed a positive effect of female length on larval survival time indicating that larvae from larger females are less vulnerable to starvation during the early stage of life. After the intensive pike fishing, the positive effect of female length on egg weight was stronger in all age classes probably due to the released resources. Based on the high quality and amount of reproductive products in large (but not very old) females, they are important for the reproduction of pike populations. This should be considered in fisheries management.     

Correction to: Who is the ocean? Preface to the future seas 2030 special issue

Reviews in Fish Biology and Fisheries - A correction to this paper has been published: https://doi.org/10.1007/s11160-021-09657-9     

Can sensitivity analysis help to detect long-branch attraction?

The behavior of nodal support and stability in the presence of long branches were examined under simulations and an analysis of real data. Relatively short branches were typically correctly resolved, received high bootstrap support, and were stable in sensitivity analyses. Longer branches received lower support and stability measures, and were often incorrectly resolved due to the long-branch attraction. Support and stability does not always correlate, and in the case of mammalian mitochondrial tree, well supported but unstable nodes were typically associated with long-branch attraction. Very long branches, on the other hand, may be incorrectly resolved with high support and stability indices. These patterns were observed both in simulations, and in the real data. The results indicate that sensitivity analysis may help to reveal phylogenetic uncertainty hidden behind artificially high support.     

Trans fat diet causes decreased brood size and shortened lifespan in Caenorhabditis elegans delta-6-desaturase mutant fat-3

Trans-fatty acids (TFAs) enter the diet through industrial processes and can cause adverse human health effects. The present study was aimed to examine the effects of dietary cis- and trans-fatty acids on the model organism Caenorhabditis elegans. Cis- or trans-18:1n9 triglycerides (25 μM) caused no apparent changes in the numbers of viable progeny of wild-type N2 animals. However, in fat-3 mutants lacking delta-6-desaturase, the trans-isomer caused modest decreases in lifespan and progeny after three generations. Long-chain polyunsaturated fatty acids (PUFA) profiles were significantly altered in fat-3 mutants compared to wild type but were not altered after exposure to dietary cis- or trans-18:1n9. Genome-wide expression analysis of fat-3 mutants revealed hundreds of changes. Several genes involved in fat metabolism (acs-2, fat-7, mdt-15) were significantly increased by cis- or trans-18:1n9 without discrimination between isomers. These results provide support for the hypothesis that dietary trans fats are detrimental to development and aging.     

Developmental origins of physical fitness: the Helsinki Birth Cohort Study

Background

Cardiorespiratory fitness (CRF) is a major factor influencing health and disease outcomes including all-cause mortality and cardiovascular disease. Importantly CRF is also modifiable and could therefore have a major public health impact. Early life exposures play a major role in chronic disease development. Our aim was to explore the potential prenatal and childhood origins of CRF in later life.

Methods/Principal Findings

This sub-study of the HBCS (Helsinki Birth Cohort Study) includes 606 men and women who underwent a thorough clinical examination and participated in the UKK 2-km walk test, which has been validated against a maximal exercise stress test as a measure of CRF in population studies. Data on body size at birth and growth during infancy and childhood were obtained from hospital, child welfare and school health records. Body size at birth was not associated with adult CRF. A 1 cm increase in height at 2 and 7 years was associated with 0.21 ml/kg/min (95% CI 0.02 to 0.40) and 0.16 ml/kg/min (95% CI 0.03 to 0.28) higher VO_2max, respectively. Adjustment for adult lean body mass strengthened these findings. Weight at 2 and 7 years and height at 11 years became positively associated with CRF after adult lean body mass adjustment. However, a 1 kg/m² higher BMI at 11 years was associated with −0.57 ml/kg/min (95% CI −0.91 to −0.24) lower adult VO_2max, and remained so after adjustment for adult lean body mass.

Conclusion/Significance

We did not observe any significant associations between body size at birth and CRF in later life. However, childhood growth was associated with CRF in adulthood. These findings suggest, importantly from a public point of view, that early growth may play a role in predicting adult CRF.     

Increased expression of the dyslexia candidate gene DCDC2 affects length and signaling of primary cilia in neurons

DCDC2 is one of the candidate susceptibility genes for dyslexia. It belongs to the superfamily of doublecortin domain containing proteins that bind to microtubules, and it has been shown to be involved in neuronal migration. We show that the Dcdc2 protein localizes to the primary cilium in primary rat hippocampal neurons and that it can be found within close proximity to the ciliary kinesin-2 subunit Kif3a. Overexpression of DCDC2 increases ciliary length and activates Shh signaling, whereas downregulation of Dcdc2 expression enhances Wnt signaling, consistent with a functional role in ciliary signaling. Moreover, DCDC2 overexpression in C. elegans causes an abnormal neuronal phenotype that can only be seen in ciliated neurons. Together our results suggest a potential role for DCDC2 in the structure and function of primary cilia.     

Involvement of a class III peroxidase and the mitochondrial protein TSPO in oxidative burst upon treatment of moss plants with a fungal elicitor

Production of apoplastic reactive oxygen species (ROS), or oxidative burst, is among the first responses of plants upon recognition of microorganisms. It requires peroxidase or NADPH oxidase (NOX) activity and factors maintaining cellular redox homeostasis. Here, PpTSPO1 involved in mitochondrial tetrapyrrole transport and abiotic (salt) stress tolerance was tested for its role in biotic stress in Physcomitrella patens, a nonvascular plant (moss). The fungal elicitor chitin caused an immediate oxidative burst in wild-type P. patens but not in the previously described ΔPrx34 mutants lacking the chitin-responsive secreted class III peroxidase (Prx34). Oxidative burst in P. patens was associated with induction of the oxidative stress-related genes AOX, LOX7, and NOX, and also PpTSPO1. The available ΔPpTSPO1 knockout mutants overexpressed AOX and LOX7 constitutively, produced 2.6-fold more ROS than wild-type P. patens, and exhibited increased sensitivity to a fungal necrotrophic pathogen and a saprophyte. These results indicate that Prx34, which is pivotal for antifungal resistance, catalyzes ROS production in P. patens, while PpTSPO1 controls redox homeostasis. The capacity of TSPO to bind harmful free heme and porphyrins and scavenge them through autophagy, as shown in Arabidopsis under abiotic stress, seems important to maintenance of the homeostasis required for efficient pathogen defense.     

Biomarker responses and accumulation of hazardous substances in mussels (Mytilus trossulus) transplanted along a pollution gradient close to an oil terminal in the Gulf of Finland (Baltic Sea)

Baltic Sea blue mussels (Mytilus trossulus) were used as sentinel organisms to detect the biological effects of chemical contamination in the low salinity environment. Mussels naturally adapted to a salinity of ca. 6.0 PSU were caged for 30 days at four sites along an assumed pollution gradient (salinity ca. 4.5 PSU) in the vicinity of Finland's largest oil refinery and harbor Kilpilahti in the Gulf of Finland. Tissue concentrations and accumulation rates of especially organic contaminants (PAHs, PCBs and organotins) were clearly elevated at the innermost coastal stations near the harbor area. Biological effects of contaminant exposure on caged mussels were evaluated by measuring a suite of biomarkers including catalase, glutathione S-transferase, superoxide dismutase, glutathione reductase, lipid peroxidation, acetylcholinesterase activity and lysosomal membrane stability. Mussels transplanted near the harbor area were able to elevate their antioxidant defense in response to environmental contamination. Reduced morphometric condition index and soft tissue growth rate together with increased lipid peroxidation and low lysosomal membrane stability were also observed at the most contaminated site. The results suggest that caging of M. trossulus for four weeks at lower salinity is a feasible method for the detection of environmental pollution also in low salinity areas of the Baltic Sea.