Molecular characterization of the HSP70 and HSP90 genes in Asian clam ( Corbicula fluminea ) and their expression analysis during heavy metal exposure

AbstractThe Asian Clam (Corbicula fluminea) is a valuable commercial and medicinal bivalve, which is widely distributed in East and Southeast Asia. As a natural nutrient source, the clam is rich in protein, amino acids, and microelements. The genome of C. fluminea has not yet been characterized; therefore, genome-assisted breeding and improvements cannot yet be implemented. In this work, we present a de novo chromosome-scale genome assembly of C. fluminea using PacBio and Hi-C sequencing technologies. The assembled genome comprised 4728 contigs, with a contig N50 of 521.06 Kb, and 1,215 scaffolds with a scaffold N50 of 70.62 Mb. More than 1.51 Gb (99.17%) of genomic sequences were anchored to 18 chromosomes, of which 1.40 Gb (92.81%) of genomic sequences were ordered and oriented. The genome contains 38,841 coding genes, 32,591 (83.91%) of which were annotated in at least one functional database. Compared with related species, C. fluminea had 851 expanded gene families and 191 contracted gene families. The phylogenetic tree showed that C. fluminea diverged from Ruditapes philippinarum, ~ 228.89 million years ago (Mya), and the genomes of C. fluminea and R. philippinarum shared 244 syntenic blocks. Additionally, we identified 2 MITF members and 99 NLRP members in C. fluminea genome. The high-quality and chromosomal Asian Clam genome will be a valuable resource for a range of development and breeding studies of C. fluminea in future research.

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Smoke on the Water: Comparative Assessment of Combined Thermal Shock Treatments for Control of Invasive Asian Clam, Corbicula fluminea

Environmental Management ◽

10.1007/s00267-021-01474-x ◽

2021 ◽

Author(s):

Neil E. Coughlan ◽

Ross N. Cuthbert ◽

Eoghan M. Cunningham ◽

Stephen Potts ◽

Diarmuid McSweeney ◽

...

Keyword(s):

Thermal Shock ◽

High Intensity ◽

Corbicula Fluminea ◽

Freshwater Ecosystems ◽

Thermal Treatments ◽

Dry Ice ◽

Open Flame ◽

Asian Clam ◽

Clam Corbicula ◽

Expensive Process

AbstractSuppression of established populations of invasive alien species can be a complex and expensive process, which is frequently unsuccessful. The Asian clam, Corbicula fluminea (Müller, 1774), is considered a high impact invader that can adversely alter freshwater ecosystems and decrease their socioeconomic value. To date, C. fluminea continues to spread and persist within freshwater environments worldwide, despite repeated management attempts to prevent dispersal and suppress established populations. As extensive C. fluminea beds can often become exposed during low-water conditions, the direct application of hot or cold thermal shock treatments has been proposed as suitable mechanism for their control. Further, mechanical substrate disturbance may enhance the efficacy of thermal shock treatments by facilitating exposures to multiple layers of buried clams. In the present study, we advanced these methods by assessing combined applications of both hot and cold thermal shock treatments for control of C. fluminea, using steam spray (≥100 °C; 350 kPa), low- or high-intensity open-flame burns (~1000 °C) and dry ice (−78 °C). In a direct comparison of raking combined with hot thermal shock applications, both steam and high-intensity open-flame treatments tended to be most effective, especially following multiple applications. In addition, when hot thermal treatments are followed by a final cold shock (i.e. dry ice), steam treatments tended to be most effective. Further, when dry ice was applied either alone or prior to an application of a hot shock treatment, substantial if not complete C. fluminea mortality was observed. Overall, this study demonstrated that combined applications of hot and cold thermal shock treatments, applied following the disruption of the substrate, can substantially increase C. fluminea mortality compared to separate hot or cold treatments.

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Bioaccessibility-corrected health risk of heavy metal exposure via shellfish consumption in coastal region of China

Environmental Pollution ◽

10.1016/j.envpol.2021.116529 ◽

2021 ◽

Vol 273 ◽

pp. 116529

Author(s):

Minwei Chai ◽

Ruili Li ◽

Yuan Gong ◽

Xiaoxue Shen ◽

Lingyun Yu

Keyword(s):

Heavy Metal ◽

Health Risk ◽

Coastal Region ◽

Metal Exposure ◽

Heavy Metal Exposure

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Relationship between heavy metal exposure and type 2 diabetes: a large-scale retrospective cohort study using occupational health examinations

BMJ Open ◽

10.1136/bmjopen-2020-039541 ◽

2021 ◽

Vol 11 (3) ◽

pp. e039541

Author(s):

Jun Ho Ji ◽

Mi Hyeon Jin ◽

Jung-Hun Kang ◽

Soon Il Lee ◽

Suee Lee ◽

...

Keyword(s):

Heavy Metals ◽

Type 2 Diabetes ◽

Heavy Metal ◽

Cohort Study ◽

Retrospective Cohort ◽

Metal Exposure ◽

Heavy Metal Exposure ◽

Lead And Cadmium

ObjectivesTo investigate the associations between heavy metal exposure and serum ferritin levels, physical measurements and type 2 diabetes mellitus (DM).DesignA retrospective cohort study.SettingChangwon, the location of this study, is a Korean representative industrial city. Data were obtained from medical check-ups between 2002 and 2018.ParticipantsA total of 34 814 male subjects were included. Of them, 1035 subjects with lead exposure, 200 subjects with cadmium exposure and the 33 579 remaining were assigned to cohort A, cohort B and the control cohort, respectively. Data including personal history of alcohol and smoking, age, height, weight, the follow-up duration, haemoglobin A1c (HbA1c), fasting blood sugar (FBS), ferritin levels, and lead and cadmium levels within 1 year after exposure were collected.Primary outcome measureIn subjects without diabetes, changes in FBS and HbA1c were analysed through repeated tests at intervals of 1 year or longer after the occupational exposure to heavy metals.ResultsIn Cohort A, DM was diagnosed in 33 subjects. There was a significant difference in lead concentrations between the subjects diagnosed with DM and those without DM during the follow-up period (3.94±2.92 mg/dL vs 2.81±2.03 mg/dL, p=0.002). Simple exposure to heavy metals (lead and cadmium) was not associated with DM in Cox regression models (lead exposure (HR) 1.01, 95% CI: 0.58 to 1.77, p 0.971; cadmium exposure HR 1.48, 95% CI: 0.61 to 3.55, p=0.385). Annual changes in FBS according to lead concentration at the beginning of exposure showed a positive correlation (r=0.072, p=0.032).ConclusionOur findings demonstrated that simple occupational exposure to heavy metals lead and cadmium was not associated with the incidence of DM. However, lead concentrations at the beginning of the exposure might be an indicator of DM and glucose elevations.

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