Hyriopsis cumingii is a major freshwater pearl mussel in the world. In order to investigate the functional roles of the growth- and mineralization-related genes involved in the pearl formation process after the inserting nucleus into the mantle tissue of H. cumingii, we conducted a transcriptome analysis of data from different time periods after the pearl-nucleus insertion. We screened a total of 1,898 growth-related unigenes and 716 mineralization-related unigenes, including 12 growth-related differential genes and eight mineralization-related differential genes that showed sustained differential expression throughout the pearl formation. The results of the gene expression patterns among samples at different time points showed that the Mcon group and the M05d group clustered together, the M50d group and the M90d group clustered together, while the M20d group clustered separately. The overall density distribution of differential gene analysis at different periods after pearl-nucleus insertion of H. cumingii, cluster analysis, differential gene analysis, differential gene differential, and co-expression analysis together revealed that growth and mineralization-related genes have the same expression pattern and jointly regulate pearl formation. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment revealed that the same functional cluster and pathway were together present on the enrichment results of both growth- and mineralization-related genes, suggesting a synergistic effect between growth and mineralization. We found that genes such as bone morphogenetic proteins (BMPs) and calmodulin (CALM) are jointly involved in growth and mineralization processes. The study indicate that growth genes cooperate with mineralization genes to play biological roles in the early process of pearl formation in H. cumingii.

Bone morphogenetic proteins (BMPs) play an important biological role in pearl biomineralization in pearl mussels. In this study, based on the genome data of the triangular sail mussel (Hyriopsis cumingii), the genome-wide identification and bioinformatic analysis of BMP gene family were performed, and the expression pattern of the BMP genes was investigated by the insertion experiments. The results showed that a total of 12 BMP gene family members (BMP2a/2b, BMP3, BMP5a/5b, BMP7a/7b/7c, BMP9, BMP10a/10b, and BMP11) were identified, which were unevenly distributed on chromosome 3/14/18, encoding 169–583 amino acids, with molecular weights ranging from 19.32 to 65.99 kDa. BMP2a, BMP7b, and BMP10a were distributed, respectively, in the cytoplasm, endoplasmic reticulum and mitochondria, others were distributed in the nucleus. qRT-PCR results showed the significant tissue specificity in BMPs gene expression. The HcBMPs were differentially expressed in the mantle and visceral mass, and the expression level was higher in the visceral mass. The expressing trends of HcBMPs were not consistent between the mantle and visceral mass insertion, suggesting that HcBMPs may perform different functions. We also found that insertion surgery in the mantle and visceral mass significantly alters the expression profiling of the BMP gene family. Insertion of the mantle induced the biomineralization function of BMP2a, BMP7a, and BMP7b, while BMP3 and BMP10b played opposite roles in visceral mass insertion. Visceral mass insertion could suppress BMP9 expression at 5 d and BMP5b expression at 90 d after insertion This work lays the foundation and data support for the preliminary elucidation of regulatory role and mechanism of HcBMPs in the pearl-cultivating process of mantle and visceral mass.

Background: Neonatal hyperbilirubinaemia (NHB) affects approximately 60% of term infants and is a recognised cause of bilirubin-induced neurologic dysfunction (BIND); however, its subclinical neurodevelopmental sequelae have not been well characterised at the level of specific developmental domains. Objectives: We aimed to use the Griffiths Developmental Scales–Chinese Edition (GDS-C) to characterise the domain-specific neurodevelopmental profile of term infants with NHB and to identify clinical risk factors for adverse outcomes. Methods: We conducted a single-centre, retrospective cohort study of 123 term newborns delivered between September 2019 and August 2023 at a tertiary hospital in Shanghai, China; 77 had NHB and 46 were healthy controls. Neurodevelopmental outcomes were assessed using the GDS-C at a median age of 46.9 months (interquartile range [IQR], 36.4–59.7) by a single certified examiner who was blinded to bilirubin status. A developmental quotient (DQ) below 85 (>1 SD below the standardised mean of 100) or at or below the 10th percentile was classified as below cutoff; otherwise, performance was classified as within the normal range. To account for testing across six domains, a Bonferroni-adjusted significance threshold of p < 0.0083 was applied. Results: Compared to the control group, the jaundice group had higher proportions of below-cutoff performance in the Locomotor (26.0% vs. 10.9%; p = 0.045), Personal–Social (28.6% vs. 10.9%; p = 0.022), Eye and Hand Coordination (29.9% vs. 10.9%; p = 0.015) and Performance (35.1% vs. 15.2%; p = 0.018) domains. Among infants with severe hyperbilirubinaemia (total serum bilirubin (TSB) ≥ 342 μmol/L; n = 19), the proportions of below-cutoff performance in the Locomotor (47.4% vs. 19.0%; p = 0.032), Personal–Social (57.9% vs. 19.0%; p = 0.003) and Performance (57.9% vs. 27.6%; p = 0.034) domains exceeded those in the non-severe subgroup. Jaundice lasting ≥ 14 days was associated with poorer personal–social outcomes (p = 0.007). In multivariable logistic regression, both a peak TSB ≥ 342 μmol/L (adjusted odds ratio [aOR], 5.59; 95% confidence interval [CI], 1.64–19.02; p = 0.006) and a jaundice duration ≥ 14 days (aOR, 5.68; 95% CI, 1.61–20.04; p = 0.007) were independently associated with below-cutoff personal–social performance. Conclusions: Among term infants, NHB was associated with an increased risk of below-cutoff performance across several GDS-C domains, particularly those reflecting gross motor, personal–social and visual-spatial functions. Severe hyperbilirubinaemia and prolonged jaundice were independent risk factors. The GDS-C may serve as a sensitive, domain-specific instrument for the early identification of infants at risk of adverse neurodevelopmental outcomes.