Stromalin Constrains Memory Acquisition by Developmentally Limiting Synaptic Vesicle Pool Size

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Secreting oviduct epithelial cells of Coturnix coturnix japonica (QOEC) and changes to their proteome after nonviral transfection

The quail oviduct (Coturnix c. japonica) is a natural candidate avian bioreactor, while the secretive quail oviduct epithelial cells (QOECs) are potential in vitro producers of recombinant proteins and vaccines. In view of the need for highly performing and transformable cell lines, QOEC may potentially act as an alternative bioreactor platform to the existing ones, for example, to the Chinese hamster ovary. The aim of this work was to characterize QOECs and their response to nucleofection with a nonviral plasmid DNA carrying the human interferon-α 2a gene (hIFNλ2a), in vitro. Primary QOEC cultures from laying quails (10-15 weeks old) were characterized by their proliferation rate, doubling time, and multilineage differentiation. Electroporation to cell nuclei (nucleofection) was used to deliver nonviral plasmid DNA containing a reporter GFP and hIFN under the ovalbumin promoter. The posttransfection analysis included polymerase chain reaction, Western blot analysis, and liquid chromatography coupled to tandem mass spectrometry. QOEC showed a typical epithelial characteristic in a primary 2D monolayer culture system and retained secretive potential up to the first passage. QOEC showed differentiation into osteoblastic lineage after stimulation. The nucleofection mean efficiency was low (2.3%). Differences of up to 10% in the proteomic profiles between nontransfected and transfected QOEC were found, the most important of these were related to the absence of keratins and cell-adhesion proteins in the transfected QOEC. Concluding, with the practical information provided here, QOEC have the potential to serve as an avian secreting cellular platform. QOEC may be further transformed to cell lineage to meet the requirement for a stable, electrocompetent, and transfectable model. The first proteomic comparison of QOEC delivered in this study showed, in the majority, a stable proteome of the nontransfected vs transfected QOEC.     

Improvement of almond production using Bombus terrestris (Hymenoptera: Apidae) in Mediterranean conditions

Almond trees are one of the most important crops in the Balearic Islands. The pollination of almonds is limited to the activity of insects, and cross‐pollination is necessary for fruit development. Currently, honey bees and wild bee populations are declining considerably due to multiple causes, such as the use of pesticides, diseases and habitat loss. An alternative to increase the almond production is the use of commercial pollinators. In this long‐term (3 years) study, the effect of the introduction of Bombus terrestris colonies on almond production was evaluated in two orchards. Two experimental designs were carried out to study the best management of this pollinator. For 2 years, all bumble bee colonies were placed in the middle of the plot and during the last year, the bumble bee colonies were distributed homogenously in the plot. Fruit set and the foraging behaviour of bumble bees during the blossoming period was determined, and the effect of different environmental variables on the visitation rate of bumble bees was assessed by means of a generalized linear mixed model (GLMM). Moreover, for the first time, the spatial distribution of fruit set was evaluated. Our results show that fruit set was significantly higher in the fields where B. terrestris had been introduced than in the control plots. This increased production resulted in a positive economic balance for the farmer. Moreover, bumble bees showed to prefer trees in a southwest orientation that were close to their colony. The activity of bumble bees showed to be significantly influenced by wind speed (the higher the speed the more flowers are visited by B. terrestris) and time after flowering (visitation rate decreased with days after flowering). In order to improve its management and obtain the highest possible almond production, it is important to understand the activity and behaviour of this pollinator.     

Modelling time‐varying low‐temperature‐induced mortality rates for pupae of Tuta absoluta (Gelechiidae,Lepidoptera)

In a series of laboratory experiments, acclimated pupae of Tuta absoluta were exposed to various constant low temperatures in order to estimate their maximum survival times (Kaplan–Meier, Lt_99.99). A Weibull function was fitted to the data points, describing maximum survival time as a function of temperature. In another experiment at ?6°C, the progress of mortality increasing with exposure time was identified. These values were fitted by a sigmoidal function converging asymptotically to 100% mortality for very long exposure times. Analysing mortality data from the maximum survival experiment by a generalized linear model showed a significant common slope parameter (p < .001) that reveals parallelism of the survival curves at each temperature if a log time axis is used. These curves appear stretched (time scaled) if plotted with a nonlogarithmic time axis. By combining these mathematical relations, it was possible to calculate a species‐specific ‘mortality surface’ which exhibits mortalities, depending on temperature and duration of exposure. In order to accumulate hourly mortalities for courses of varying temperatures, an algorithm was developed which yields mortality values from that surface taking into account the attained mortality level. In validation experiments, recorded mortalities were compared against modelled mortalities. Prediction of mortality was partially supported by the model, but pupae experiencing intensely fluctuating temperatures showed decreased mortality, probably caused by rapid cold hardening during exposure. Despite this observation, mortality data converged to distinct levels very close to 100% depending on the intensity of temperature fluctuations that were characteristic for different types of experiments. The highest mortality limit occurred at intensely fluctuating temperatures in laboratory experiments. This constituted a benchmark that was not reached under various field conditions. Thus, it was possible to identify temperature limits for the extinction of field populations of Tuta absoluta pupae.     

Haemolymph ecdysteroids in the solitary and gregarious larvae of Schistocerca gregaria

In the penultimate and last instar larvae of Schistocerca gregaria, 20-hydroxyecdysone (20E) makes up 74–84% of detected ecdysteroids in the females, and 63–74% in the males. Remaining ecdysteroids include ecdysone, a compound with HPLC and TLC retention times of makisterone A, and highly polar metabolites. Except for the last instar females, the contents of ecdysone and the unknown compound are higher in the solitary phase, while that of polar metabolites is higher in the gregarious phase. The phases also differ in that the molt-inducing ecdysteroid peaks last longer in the gregarious than in the solitary larvae. Peak concentrations reach 3.0–4.0 μg 20E equiv./ml in penultimate female instar, 2.5–3.0 μg/ml in penultimate male instar, and 1.5–2.0 μg/ml in the last larval instar of both sexes. © 1996 Wiley-Liss, Inc.     

Slow Recovery from Inbreeding Depression Generated by the Complex Genetic Architecture of Segregating Deleterious Mutations

The deleterious effects of inbreeding have been of extreme importance to evolutionary biology, but it has been difficult to characterize the complex interactions between genetic constraints and selection that lead to fitness loss and recovery after inbreeding. Haploid organisms and selfing organisms like the nematode Caenorhabditis elegans are capable of rapid recovery from the fixation of novel deleterious mutation; however, the potential for recovery and genomic consequences of inbreeding in diploid, outcrossing organisms are not well understood. We sought to answer two questions: 1) Can a diploid, outcrossing population recover from inbreeding via standing genetic variation and new mutation? and 2) How does allelic diversity change during recovery? We inbred C. remanei, an outcrossing relative of C. elegans, through brother-sister mating for 30 generations followed by recovery at large population size. Inbreeding reduced fitness but, surprisingly, recovery from inbreeding at large populations sizes generated only very moderate fitness recovery after 300 generations. We found that 65% of ancestral single nucleotide polymorphisms (SNPs) were fixed in the inbred population, far fewer than the theoretical expectation of ∼99%. Under recovery, 36 SNPs across 30 genes involved in alimentary, muscular, nervous, and reproductive systems changed reproducibly across replicates, indicating that strong selection for fitness recovery does exist. Our results indicate that recovery from inbreeding depression via standing genetic variation and mutation is likely to be constrained by the large number of segregating deleterious variants present in natural populations, limiting the capacity for recovery of small populations.     

A commentary on the paper: ‘Evaluation of spice and herb as phytoderived selective modulators of human retinaldehyde dehydrogenases using a simple in vitro method’

It is commonly known that aldehyde dehydrogenases (ALDHs) are a promising therapeutic target in many diseases. Bui et al.—the authors of the paper I am discussing here (Biosci Rep (2021) 41(5): BSR20210491 https://doi.org/10.1042/BSR20210491)—point that there is a lack of research on the use of spices and herbs as the sources of naturally occurring modulators of ALDH activity. In order to carry out this type of research, the authors prepared ethanolic extracts of 22 spices and herbs. The main objective of the study was to investigate retinaldehyde dehydrogenases (RALDHs), of which retinal is the main substrate and ALDH2, the mitochondrial isoform, having acetaldehyde as the main substrate.The obtained results indicated that the tested extracts exhibited differential regulatory effects on RALDHs/ALDH2 and some of them showed a potential selective inhibition of the activity of RALDHs.