Xiuling Li

Aquatic environments have long been threatened by heavy metal pollution, which poses potential risks to human health. Rizhao City, in a typical coastal area, has witnessed increasingly severe heavy metal contamination in its aquatic systems. To comprehensively assess the status of heavy metal pollution in the aquatic environment and formulate effective mitigation strategies, this study focused on the water, sediments and Pseudorasbora parva from the major rivers and reservoirs in Rizhao City. The distribution characteristics and potential sources of Cr, Ni, Cu, As and Pb were systematically analysed. Ecological risks were evaluated using indices such as the water quality index (WQI), geoaccumulation index (I_geo), bioconcentration factor (BCF), estimated daily intake (EDI), target hazard quotient (THQ) and incremental lifetime cancer risk (ILCR). The results revealed that the average concentrations of heavy metals in water followed the order Cr > Ni > Cu > As > Pb, with variations across different rivers and reservoirs. In sediments, Cr and Ni exhibited higher concentrations in the Chaobai River (CR), reaching 45.21 and 34.87 mg kg⁻¹, respectively. Cr and Ni showed higher enrichment in the gills and viscera of P. parva compared to muscle tissues, while the distribution patterns of Cu, As and Pb were more complex. WQI assessments indicated that all sampling sites had WQI values I_geo values for Ni and Cu in CR sediments were −0.52 and −0.21, respectively, approaching the threshold and warranting attention to potential contamination risks. BCF results demonstrated stronger enrichment capabilities in gills and viscera. Health risk assessments revealed that EDI was correlated with heavy metal concentrations in fish tissues, with THQ > 1 and ILCR > 1.0 × 10⁻⁴ for gills, indicating potential health threats to frequent consumers from long-term ingestion.

Microcystis aeruginosa (M. aeruginosa), a key species in cyanobacterial blooms, is notably concerning due to its production of harmful microcystins (MCs). In this study, the differences in the ability of MC-producing and MC-free strains of M. aeruginosa to respond to the exogenous MCs (MC-LR) were compared. The results showed that at higher concentrations, MC-LR affected cell morphology, cell growth, photosynthetic efficiency, and induced oxidative stress in M. aeruginosa. Under high MC-LR concentration exposure, MC-producing strains showed a 14.7% reduction in cell density, accompanied by a 32% elevation in Vj and a 63.1% decline in F_V/F_M. MC-free strains showed cell density decreasing by 22.5%, Vj increasing 2-fold, and F_V/F_M dropping by 69.5%. The inhibitory effect of MC-LR at higher concentrations was found to be stronger in MC-free compared to MC-producing strains. In addition, MC-LR reduced the efficiency of photosystem II by blocking electron transfer from QA to QB; for MC-free strains, MC-LR may have acted as a signaling molecule affecting the targeting of QB on the D1 protein, thus leading to QB detachment from the protein complex. Metabolomics analysis showed that MC-LR affects arginine synthesis in M. aeruginosa and thus the synthesis and release of MCs.

Myricaria wardii Marquand 1929, endemic to the Tibet Plateau, is a perennial shrub with important medicinal and ecological values. In this study, the complete chloroplast (cp) genome of M. wardii was assembled, and the phylogenetic tree was reconstructed to evaluate the phylogenetic location of the species. The results showed that the cp genome size of the M. wardii was 155,299 bp, which contained a pair of inverted repeat (IR) regions (26,150 bp), a large single copy (LSC) region (84,715 bp), and a small single copy (SSC) region (18,284 bp). The total GC content of the cp genome was 36.30%. A total of 128 genes were annotated, consisting of 83 protein-coding genes, 37 tRNA genes and 8 rRNA genes. The phylogenetic analysis showed that M. wardii was closely related to M. prostrata. This study provides useful information for the conservation of this species and the phylogenetic analysis of Tamaricaceae.

Background: Trapa L. is a floating-leaved aquatic plant with important economic and ecological values. However, the species identification and phylogenetic relationship within Trapa are still controversial, which necessitates the need for plastid genome information of Trapa. In this study, complete chloroplast genomes of 13 Trapa species/taxa were sequenced and annotated. Combined with released sequences, comparative analyses of chloroplast genomes were performed on the 15 Trapa species/taxa for the first time. Results: The Trapa chloroplast genomes exhibited typical quadripartite structures with lengths from 155,453 to 155,559 bp. The gene orders and contents within Trapa were conservative, but several changes were found in the microstructure. The intron loss of rpl2, also detected in Lythraceae, was found in all Trapa species/taxa, suggesting close genetic relationship between Lythraceae and Trapaceae. Notably, two small-seed species (T. incisa and T. maximowiczii) showed the smallest genome size with 155,453 and 155,477 bp, respectively. Each cp genome contained the same 130 genes consisting of 85 protein-coding genes, 37 tRNA genes and 8 rRNA genes. Trapa species/taxa showed 37 (T. incisa and T. maximowiczii) to 41 (T. sibirica) long repeats, including forward, palindromic, reversed and complementary repeats. There were 110 (T. quadrispinosa) to 123 (T. incisa and T. maximowiczii) SSR (simple sequence repeat) loci in Trapa chloroplast genomes. Comparative analyses revealed that two hotspot regions (atpA—atpF and rps2—rpoC2) in Trapa chloroplast genomes could be served as potential molecular markers. Three phylogenetic analyses (ML, MP and BI) consistently showed that there were two clusters within Trapa, including large- and small-seed species/taxa, respectively; for the large-seed Trapa, they clustered according to their geographical origin and tubercle morphology on the surface of seeds. Conclusion: In summary, we have acquired the sequences of 13 Trapa chloroplast genomes, and performed the comparative analyses within Trapa for the first time. The results have helped us better identify the Trapa species/taxa and deepen the understanding of genetic basis and phylogenetic relationship of Trapa, which will facilitate the effective management and utilization of the important genetic resources in the future.

Folic acid is a water-soluble B vitamin, and plays an important role in regulating gene expression and methylation. The liver is the major site of lipid biosynthesis in the chicken. Nevertheless, how gene expression and regulatory networks are affected by folic acid in liver of broilers are poorly understood. This paper conducted the RNA-seq technology on the liver of broilers under folic acid challenge investigation. First, 405 differentially expressed genes (DEGs), including 157 significantly upregulated and 248 downregulated, were detected between the control group (C) and the 5 mg folic acid group (M). Second, 68 upregulated DEGs and 142 downregulated DEGs were determined between C group and 10 mg folic acid group (H). Third, there were 165 upregulated genes and 179 downregulated genes between M and H groups. Of these DEGs, 903 DEGs were successfully annotated in the public databases. The functional classification based on GO and KEEGG showed that “general function prediction only” represented the largest functional classes, “cell cycle” (C vs. M; M vs. H), and “neuroactive ligand-receptor interaction” (C vs. H) were the highest unique sequences among three groups. SNP analysis indicated that numbers of C, M and H groups were 145,450, 146,131, and 123,004, respectively. Total new predicted alternative splicing events in C, M, and H groups were 9,521, 9,328, and 8,929, respectively. A protein-protein interaction (PPI) network was constructed, and the top 10 hub genes were evaluated among three groups. The results of real time PCR indicated that mRNA abundance of PPARγ and FAS in abdominal fat of M and H groups were reduced compared with the C group (P < 0.05). Ultramicroscopy results showed that folic acid could reduce lipid droplets in livers from chickens. Finally, contents of LPL, PPARγ, and FAS in abdominal fat were decreased with the folic acid supplmented diets (P < 0.01). These findings reveal the effects of folic acid supplemention on gene expression in liver of broilers, which can provide information for understanding the molecular mechanisms of folic acid regulating liver lipid metabolism.

Trapa L., an annual floating-leaved herb, is widely distributed in the old world and has important edible and medicinal values. However, the taxonomy and phylogeny of Trapa are unclear. Here, we reported the complete chloroplast genome of a wild species with small nuts, T. incisa. The complete chloroplast genome size of T. incisa was 155, 453 bp, consisting of two inverted repeat (IR) regions (24, 388 bp), one large single copy (LSC) region (88, 398 bp) and one small single copy (SSC) region (18, 279 bp). A total of 129 genes were annotated, including 83 protein-coding genes, 38 tRNA genes and 8 rRNA genes. Among them, 19 genes were duplicated (6 protein-coding genes, 9 tRNA genes and 4 rRNA genes). The phylogenomic analysis suggested a close relationship between T. incisa and T. maximowiczii.

Trapa L. is floating-leaved aquatic plants with important economic and ecological values. However, species identification and phylogenetic relationship are still unresolved for Trapa . In this study, complete chloroplast genomes of 13 Trapa species/taxa were sequenced and annotated. Combined with released sequences of the other two species, comparative analysis of cp genomes was first performed on the 15 Trapa species/taxa. The 15 cp genomes exhibited quadripartite structures with medium size of 155, 453-155, 559 bp. IR/SC junctions were conservative with no obvious change found. Long repetitive repeats and SSRs were mostly detected in the intergenic and LSC regions, providing useful plastid markers for species and relationship identification. Three phylogenetic analyses (MP, ML and BI) consistently showed two clusters within Trapa , including large- and small-seed species/taxa, respectively. This study provided the baseline information for phylogeography of Trapa , which would facilitate the management and utilization of genetic resources of the genus.