Experience-dependent learning of behavioral laterality in the scale-eating cichlid Perissodus microlepis occurs during the early developmental stage

Behavioral laterality—typically represented by human handedness—is widely observed among animals. However, how laterality is acquired during development remains largely unknown. Here, we examined the effect of behavioral experience on the acquisition of lateralized predation at different developmental stages of the scale-eating cichlid fish Perissodus microlepis. Naïve juvenile fish without previous scale-eating experience showed motivated attacks on prey goldfish and an innate attack side preference. Following short-term predation experience, naïve juveniles learned a pronounced lateralized attack using their slightly skewed mouth morphology, and improved the velocity and amplitude of body flexion to succeed in foraging scales during dominant-side attack. Naïve young fish, however, did not improve the dynamics of flexion movement, but progressively developed attack side preference and speed to approach the prey through predation experience. Thus, the cichlid learns different aspects of predation behavior at different developmental stages. In contrast, naïve adults lost the inherent laterality, and they neither developed the lateralized motions nor increased their success rate of predation, indicating that they missed appropriate learning opportunities for scale-eating skills. Therefore, we conclude that behavioral laterality of the cichlid fish requires the integration of genetic basis and behavioral experiences during early developmental stages, immediately after they start scale-eating.

Myotonic dystrophy type 1 embryonic stem cells show decreased myogenic potential, increased CpG methylation at the DMPK locus and RNA mis-splicing

ABSTRACT Skeletal muscle tissue is severely affected in myotonic dystrophy type 1 (DM1) patients, characterised by muscle weakness, myotonia and muscle immaturity in the most severe congenital form of the disease. Previously, it was not known at what stage during myogenesis the DM1 phenotype appears. In this study we differentiated healthy and DM1 human embryonic stem cells to myoblasts and myotubes and compared their differentiation potential using a comprehensive multi-omics approach. We found myogenesis in DM1 cells to be abnormal with altered myotube generation compared to healthy cells. We did not find differentially expressed genes between DM1 and non-DM1 cell lines within the same developmental stage. However, during differentiation we observed an aberrant inflammatory response and increased CpG methylation upstream of the CTG repeat at the myoblast level and RNA mis-splicing at the myotube stage. We show that early myogenesis modelled in hESC reiterates the early developmental manifestation of DM1.

Microtubular TRIM36 E3 Ubiquitin Ligase in Embryonic Development and Spermatogenesis

TRIM36 is a member of the tripartite motif (TRIM) family of RING-containing proteins, also known as Haprin, which was first discovered for its abundance in testis and found to be implicated in the spermatozoa acrosome reaction. TRIM36 is a microtubule-associated E3 ubiquitin ligase that plays a role in cytoskeletal organization, and according to data gathered in different species, coordinates growth speed and stability, acting on the microtubules’ plus end, and impacting on cell cycle progression. TRIM36 is also crucial for early developmental processes, in Xenopus, where it is needed for dorso-ventral axis formation, but also in humans as bi-allelic mutations in the TRIM36 gene cause a form of severe neural tube closure defect, called anencephaly. Here, we review TRIM36-related mechanisms implicated in such composite physiological and pathological processes.

Early Developmental Signs in Children with Autism Spectrum Disorder: Results from the Japan Environment and Children’s Study

Autism spectrum disorder (ASD) is a developmental disability in early childhood. Early identification and intervention in children with ASD are essential for children and their families. This study aimed to identify the earliest signs of ASD. Using a large cohort including data from 104,062 fetal records in the Japan Environment and Children’s Study, we examined the Ages and Stages Questionnaires® (ASQ-3TM) scores of children with and without ASD. The ASQ-3 comprises five domains: communication, gross motor, fine motor, problem solving, and personal-social. The ASQ-3 scores were obtained at ages 6 months, 1 year, and 3 years. There were 64,501 children with available ASQ-3 data. The number of children diagnosed with ASD was 188 (0.29%) at 3 years of age. The highest relative risk (RR) for any domain below the monitoring score at 6 months was in the communication (RR 1.90, 95% CI 1.29–2.78, p = 0.0041), followed by fine motor (RR 1.50, 95% CI 1.28–1.76, p < 0.0001) domain. A low ASQ-3 score in the communication domain at 6 months was related to an ASD diagnosis at 3 years of age. The ASQ-3 score at 6 months can contribute to the early identification of and intervention for ASD.

Knowledge in Sight: Toddlers Plan Efficient Epistemic Actions by Anticipating Learning Gains

Anticipating the learning consequences of actions is crucial to plan efficient information-seeking. Such a capacity is needed for learners to determine which actions are most likely to result in learning. Here, we tested the early ontogeny of the human capacity to anticipate the amount of learning gained from seeing. In Study 1, we tested infants’ capacity to anticipate the availability of sight. Fourteen-month-old infants (N = 72) were invited to search for a toy hidden inside a container. The participants were faster to attempt at opening a shutter when this action allowed them to see inside the container. Moreover, this effect was specifically observed when seeing inside the container was potentially useful to the participants’ goals. Thus, infants anticipated the availability of sight, and they calibrated their information-seeking behaviors accordingly. In Studies 2-3, we tested toddlers’ capacity to anticipate whether data would be cognitively useful for their goals. Two-and-a-half-year-olds (N = 72) had to locate a target character hidden among distractors. The participants flipped the characters more often, and were comparatively faster to initiate this action when it yielded access to visual data allowing them to locate the target. Thus, toddlers planned their information-seeking behaviors by anticipating the cognitive utility of sight. In contrast, toddlers did not calibrate their behaviors to the cognitive usefulness of auditory data. These results suggest that cognitive models of learning guide toddlers’ search for information. The early developmental onset of the capacity to anticipate future learning gains is crucial for active learning.

Discovery of Sex-Determining Genes in Portunus trituberculatus: A Comparison of Male and Female Transcriptomes During Early Developmental Stages

Portunus trituberculatus is one of the main mariculture crabs of high economic value. To identify genes involved in sex determination, we first performed sex-specific transcriptome sequencing at six larval development stages using a DNA/RNA co-extraction method. A total of 907,952,938 and 828,774,880 reads were obtained from female and male crabs, respectively. 2,379 differentially expressed genes (DEGs) were found between females and males, and were mainly enriched in DNA replication, folate biosynthesis, and retinol metabolism pathways. Furthermore, transcription patterns of genes in the sex-determining region (SD) were analyzed based on the transcriptome data, and one Dmrt gene (PtDMY) was found to be exclusively expressed in males during early developmental stages. Notably, some known sex-related genes, including IAG, Dmrt11E, DmrtB1, and DmrtC2 were significantly down-regulated after knocking down PtDMY. Our results suggested that PtDMY is involved in sex determination and may be one of the key upstream regulators of the sex determination pathway. In addition, the massive volume of transcriptome data obtained in this study provided an important basis for the systematic study of sex determination mechanisms in P. trituberculatus.

Microbial community composition associated with early developmental stages of the Indian white shrimp, Penaeus indicus

Gut microbiota is known to influence the physiology, health, nutrient absorption, reproduction, and other metabolic activities of aquatic organisms. Microbial composition can influence intestinal immunity and are considered as health indicators. Information on gut microbial composition provides potential application possibilities to improve shrimp health and production. In the absence of such information for Penaeus indicus, the present study reports the microbial community structure associated with its early developmental stages. Bacterial community associated with the early developmental stages (egg, nauplii, zoea, mysis, postlarvae-1, postlarvae-6 and postlarvae-12) from two hatchery cycles were analysed employing 16S rRNA high throughput sequencing. Proteobacteria and Bacteroidetes, were the two dominant phyla in P. indicus development stages. Sequential sampling revealed the constant change in the bacterial composition at genus level. Alteromonas was dominant in egg and nauplii stage, whilst Ascidiaceihabitans (formerly Roseobacter) was the dominant genera in both PL6 and PL12. The bacterial composition was highly dynamic in early stages and our study suggests that the mysis stage is the critical phase in transforming the microbial composition and it gets stabalised by early post larval stages. This is the first report on the composition of microbiota in early developmental stages of P. indicus. Based on these results the formation of microbial composition seems to be influenced by feeding at early stages. The study provides valuable information to device intervention strategies for healthy seed production.

Heterogeneity and genomic loci of ubiquitous Cre reporter transgenes in zebrafish

The most-common strategy for zebrafish Cre/lox-mediated lineage labeling experiments combines ubiquitously expressed, lox-based Switch reporter transgenes with tissue-specific Cre or 4-OH-Tamoxifen-inducible CreERT2 driver lines. Although numerous Cre driver lines have been produced, only a few broadly expressed Switch reporters exist in zebrafish and their generation by random transgene integration has been challenging due to position-effect sensitivity of the lox-flanked recombination cassettes. Here, we compare commonly used Switch reporter lines for their recombination efficiency and reporter expression pattern during zebrafish development. Using different experimental setups, we show that ubi:Switch and hsp70l:Switch outperform current generations of two additional Switch reporters due to favorable transgene integration sites. Our comparisons also document preferential Cre-dependent recombination of ubi:Switch and hsp70l:Switch in distinct zebrafish tissues at early developmental stages. To investigate what genomic features may influence Cre accessibility and lox recombination efficiency in highly functional Switch lines, we mapped these transgenes and charted chromatin dynamics at their integration sites. Our data documents the heterogeneity among lox-based Switch transgenes towards informing suitable transgene selection for lineage labeling experiments. Our work further proposes that ubi:Switch and hsp70l:Switch define genomic integration sites suitable for universal transgene or switch reporter knock-in in zebrafish.