Ecological impacts of photosynthetic light harvesting in changing aquatic environments: A systematic literature map

Underwater light is spatially as well as temporally variable and directly affects phytoplankton growth and competition. Here we systematically (following the guidelines of PRISMA‐EcoEvo) searched and screened the published literature resulting in 640 individual articles. We mapped the conducted research for the objectives of (1) phytoplankton fundamental responses to light, (2) effects of light on the competition between phytoplankton species, and (3) effects of climate‐change‐induced changes in the light availability in aquatic ecosystems. Among the fundamental responses of phytoplankton to light, the effects of light intensity (quantity, as measure of total photon or energy flux) were investigated in most identified studies. The effects of the light spectrum (quality) that via species‐specific light absorbance result in direct consequences on species competition emerged more recently. Complexity in competition arises due to variability and fluctuations in light which effects are sparsely investigated on community level. Predictions regarding future climate change scenarios included changes in in stratification and mixing, lake and coastal ocean darkening, UV radiation, ice melting as well as light pollution which affect the underwater light‐climate. Generalization of consequences is difficult due to a high variability, interactions of consequences as well as a lack in sustained timeseries and holistic approaches. Nevertheless, our systematic literature map, and the identified articles within, provide a comprehensive overview and shall guide prospective research.     

Development of a direct test of baculovirus resistance in wild codling moth populations

The occurrence of resistance of codling moth (CM, Cydia pomonella L.) to Cydia pomonella granulovirus (CpGV) used as biological control agent revealed the need for fast and reliable resistance monitoring methods. Here, we describe the development of a laboratory resistance test that is directly performed on larvae extracted from infested apples. This test is based on a 14‐day bioassay at a discriminative CpGV concentration of 2 × 10⁵ occlusion bodies/ml diet and can be applied to L1–L4 larvae. Information on virus resistance can be obtained within <4 weeks. In a survey, CM larvae were isolated and tested from 6698 apples from 10 different orchards in Germany, Austria, Switzerland, Italy and the Netherlands. We identified seven CM populations resistant or partly resistant to CpGV isolates. Although some of the orchards were treated with commercial CpGV products, this method allowed us to obtain reliable information about the resistance status of the examined populations.     

Insulin and Hippocampus Activation in Response to Images of High‐Calorie Food in Normal Weight and Obese Adolescents

Responsiveness to food cues, especially those associated with high‐calorie nutrients may be a factor underlying obesity. An increased motivational potency of foods appears to be mediated in part by the hippocampus. To clarify this, we investigated by means of 3‐T magnetic resonance imaging (MRI) the activation of the hippocampus and associated brain structures in response to pictures of high‐calorie and low‐calorie foods in 12 obese and 12 normal‐weight adolescents. To investigate the relationship between neuronal activation patterns (e.g., hippocampus) to the caloric content of food images and plasma insulin levels, we performed a multiple regression analysis. Interestingly, a significant positive correlation between fasting plasma levels of insulin, waist circumference, and right hippocampal activation was seen after stimulation with high‐caloric food images. BMI values did not correlate significantly with the hippocampal activation. On the other hand, we found a significant negative correlation in response to high‐caloric food images and the plasma levels of insulin in the medial right gyrus frontalis superior and in the left thalamus. In summary, our data show that insulin is importantly involved in the central regulation of food intake. The significant positive relationship between hippocampal activation after stimulation with high‐caloric food images, plasma insulin levels, and waist circumference suggests a permissive role of insulin signaling pathways in the hippocampal control of eating behavior. Interestingly, only the waist circumference, as a main indicator of abdominal obesity, correlated significantly with the hippocampal activation patterns, and not the BMI.     

Effect of essential amino acids on the phosphorylation of a 40S ribosomal protein and protein synthesis in Acanthamoeba castellanii

Reversible and multiple phosphorylation of a 40S ribosomal protein is observed in a variety of eukaryotic cells. In the primitive eukaryote Acanthamoeba, one or three phosphorylated S3 derivatives are observed during growth phase in nondefined nutrient medium (ND cells) or in chemically defined nutrient medium (D cells), respectively. In both cases, stationary phase cells exhibit nonphosphorylated S3; however, transfer of these cells into the respective fresh nutrient media results in a transient accumulation of four phosphorylated S3 derivatives. Transfer of D cells into nutrient medium, deficient in all or any single essential amino acids, leads to reversible inhibition of S3 phosphorylation and growth arrest. The low level of phosphorylated S3 is not simply the consequence of growth arrest, since in cells where growth is arrested differently, the level of phosphorylated S3 can be high. In response to amino acid deficiency, a number of other changes can be observed. These include a 2-3-fold decrease of total protein synthesis, 13 changes in the cellular protein pattern, and specific alterations in the ribosome absorbance profiles and in the distribution of poly-A+ RNA within subribosomal and ribosomal fractions. While the rate of total protein synthesis seems to be associated with the level of phosphorylated S3, the level of the synthesis of at least 10 of the particular proteins can be dissociated from the level of S3 phosphorylation.     

C-bands and chiasma distribution inScilla amoena,S. ingridae,andS. mischtschenkoana (Hyacinthaceae)

An effect of C-band pattern and polymorphism on chiasma distribution in pollen meiosis was recently demonstrated inScilla siberica. A further meiotic banding study has been performed in the alliesS. amoena, S. ingridae, andS. mischtschenkoana in order to analyze the effect, if any, of their specific C-band patterns and cytochemically different heterochromatin types on recombination. No clear evidence for a preferential formation of chiasmata adjacent to homozygous intercalary heterochromatin and no consistent reduction of chiasma frequency near strongly heterozygous intercalary heterochromatin blocks, as observed inS. siberica, could be found. Terminal C-band heteromorphism is suspected to cause distal chiasma defaults. The results suggest once more that there is no uniform effect of heterochromatin on crossover distribution.