[Altered dynamics of brain spontaneous activity in betel quid dependence chewers].

Objective: To investigate the dynamic characteristics of brain spontaneous activity in betel quid dependence (BQD) chewers and its relationship with clinical indexes. Method: This study was conducted in Hainan General Hospital from April to December 2019 and the data of 53 BQD chewers (37 males and 16 females, aged 20 to 58(38±11) years) and 37 healthy controls (HC) (24 males and 13 females, aged 23-57(42±12) years) were collected. All these subjects underwent resting-state functional magnetic resonance imaging (rs-fMRI) scan. The dynamic characteristics of resting fMRI indexes, including dynamic amplitude of low-frequency fluctuations (ALFF), regional homogeneity (ReHo) and degree centrality (DC) of these subjects were calculated using the sliding time window method, parameters such as age and dynamic local consistency were analyzed and compared between the two groups. Pearson correlation was used to analyze the relationship between dynamic indexes, betel quid dependence score (BQDS) and disease duration in BQD group. Results: BQD chewers showed decreased dynamic ALFF in the left orbital prefrontal cortex (0.138±0.041 vs 0.171±0.070), the right temporal pole superior temporal gyrus (0.277±0.070 vs 0.319±0.086) and the right inferior parietal lobule (0.223±0.052 vs 0.259±0.088) than HC (all P<0.05). For regional homogeneity, BQD chewers showed a decrease dynamic ReHo in the right inferior temporal gyrus (0.055±0.008 vs 0.061±0.009), the orbital prefrontal cortex (0.058±0.005 vs 0.063±0.008), the right inferior frontal gyrus (0.081±0.006 vs 0.087±0.011), the right superior occipital gyrus (0.056±0.007 vs 0.062±0.008), the left precentral gyrus (0.068±0.008 vs 0.074±0.008), and the left superior frontal gyrus (0.058±0.008 vs 0.064±0.009) than HC (all P<0.05). BQD chewers showed an increase dynamic ReHo in the right precuneus (0.095±0.009 vs 0.089±0.008) (P<0.05). There was no significant difference in DC between the two groups (all P>0.05). The relationships between three dynamic ALFF and BQDS (r=-0.104, -0.015, -0.119), seven dynamic ReHo and BQDS (r=-0.099, -0.141, -0.055, -0.078, -0.027, -0.111, -0.090), three dynamic ALFF and disease duration (r=-0.122, -0.095, -0.171), and seven dynamic ReHo and disease duration (r=0.242, -0.252, 0.035, 0.056, 0.047, 0.081, 0.169) were not statistically significant (all P>0.05). Conclusions: BQD chewers showed a decrease dynamic ReHo and/or ALFF in multiple brain regions dominated by prefrontal cortex, and an increase dynamic ReHo in the right precuneus.

Molecular cloning, characterization, and expression of Rab5B, Rab6A, and Rab7 from Litopenaeus vannamei (Penaeidae).

The Rab protein family belongs to a superfamily of ras-like GTP-binding proteins. Rab proteins regulate many steps of membrane trafficking. In this study, three Rab family members, Rab5B, Rab6A, and Rab7, designated LvRab5B, LvRab6A, and LvRab7, were cloned from Litopenaeus vannamei. The full-length cDNA sequences of LvRab5B, LvRab6A, and LvRab7 were 1383, 873, and 767 nucleotides in length and they encoded proteins of 211, 212, and 205 amino acids, respectively. Using qRT-PCR, the mRNA expression levels of the three proteins were determined in the hepatopancreas of L. vannamei at different stages after infectious hypodermal and hematopoietic necrosis virus and white spot syndrome virus challenge. The results indicated that the mRNA expression levels of LvRab5B, LvRab6A, and LvRab7 were all significantly up-regulated after virus injection, suggesting that these genes may play essential roles in the immune response to viral infection in shrimp.

Identification of highly expressed host microRNAs that respond to white spot syndrome virus infection in the Pacific white shrimp Litopenaeus vannamei (Penaeidae).

MicroRNAs (miRNAs) are known to play an important role in regulating both adaptive and innate immunity. Pacific white shrimp (Litopenaeus vannamei) is the most widely farmed crustacean species in the world. However, little is known about the role miRNAs play in shrimp immunity. To understand the impact of viral infection on miRNA expression in shrimp, we used high-throughput sequencing technology to sequence two small RNA libraries prepared from L. vannamei under normal and white spot syndrome virus (WSSV) challenged conditions. Approximately 19,312,189 and 39,763,551 raw reads corresponding to 17,414,787 and 28,633,379 high-quality mappable reads were obtained from the two libraries, respectively. Twelve conserved miRNAs and one novel miRNA that were highly expressed (>100 RPM) in L. vannamei were identified. Of the identified miRNAs, 8 were differentially expressed in response to the virus infection, of which 1 was upregulated and 7 were downregulated. The prediction of miRNA targets showed that the target genes of the differentially expressed miRNAs were related to immunity, apoptosis, and development functions. Our study provides the first characterization of L. vannamei miRNAs in response to WSSV infection, which will help to reveal the roles of miRNAs in the antiviral mechanisms of shrimp.

Cloning, characterization, and expression of the macrophage migration inhibitory factor gene from the Pacific white shrimp Litopenaeus vannamei (Penaeidae).

The macrophage migration inhibitory factor (MIF) is an important proinflammatory cytokine that mediates both innate and adaptive immune responses. In this study, we identified a homolog of MIF in the Pacific white shrimp Litopenaeus vannamei. The MIF cDNA contained a 363-bp open reading frame encoding a 120-amino acid protein with a calculated molecular mass of 13.442 kDa and a theoretical isoelectric point of 6.57. The L. vannamei MIF shared high amino acid identity with MIFs of other invertebrates. Tissue distribution analysis by quantitative real-time polymerase chain reaction (qRT-PCR) revealed that the L. vannamei MIF was abundantly expressed in the blood, heart, and hepatopancreas, was moderately expressed in the gill, and was weakly expressed in the muscle and intestine. Furthermore, in order to gain a basic understanding of the role of MIF in the shrimp immune response against viral infection, its mRNA expression was determined in the hepatopancreas of L. vannamei at different stages after white spot syndrome virus (WSSV) challenge using qRT-PCR. The result indicated that the expression of MIF was significantly upregulated after WSSV injection, suggesting that MIF may be involved in the response to viral infection in shrimp.

Cloning, partial sequence, and single-nucleotide polymorphism of the ryanodine receptor gene of the Pacific white shrimp Litopenaeus vannamei (Penaeidae).

Ryanodine receptor/calcium release channel is a large protein that plays an essential role in muscle contraction; mutations in the ryanodine receptor gene affect sensitivity to stress. As a first step towards investigating the relationship between the ryanodine receptor and shrimp cramped muscle syndrome, we cloned, partially sequenced, and examined single-nucleotide polymorphisms (SNPs) of the ryanodine receptor gene of the Pacific white shrimp (Litopenaeus vannamei). The nucleotide sequence of a 15.06-kb L. vannamei genomic DNA segment containing a partial ryanodine receptor gene sequence was determined (deposited in GenBank nucleotide database: HM367069). Direct sequencing of PCR-amplified ryanodine receptor exons with their intron-flanking regions in 10 cramped muscle syndrome shrimp and 10 healthy shrimp, revealed seven SNPs. Five of them (1713A/G, 1749T/C, 1755T/C, 3965G/A, and 8737C/T) are located in exons; however, they appear to be neutral (synonymous), since they do not alter the encoded amino acid. The other SNPs (1553C/T and 13337A/G) are in introns. The SNPs identified in the ryanodine receptor gene could be useful for association studies aimed at determining the physiological role of the ryanodine receptor in cramped muscle syndrome of shrimp.