Chemodiversity of dissolved organic matter exports from subtropical humid catchment driven by hydrological connectivity.

The quantity and quality of dissolved organic matter (DOM) exported from source areas are closely related to hydrological linkage between source areas and streams, that is hydrological connectivity. However, understanding of how hydrological connectivity regulates the export of catchment DOM components remains inadequate. In this study, high-frequency monitoring of groundwater and runoff from subtropical humid catchment was conducted for 20 months, and hydrological connectivity was quantitatively characterized by considering both surface and subsurface hydrological processes. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was utilized to investigate the DOM molecular composition. Results showed that over half of the areas in the catchment could not persistently establish hydrological connectivity with the stream during the rainfall. The average proportion of lignin was the highest in DOM components, followed by tannin and proteins. Additionally, both modified aromaticity index and double bond equivalence reached maximums at peak discharge, reflecting terrestrial materials could increase DOM aromaticity and unsaturated degree. Partial least square-structural equation modeling revealed significantly direct effects of rainfall, antecedent conditions, and hydrological connectivity on dissolved organic carbon (DOC) export. Furthermore, nonlinear relationships were observed between hydrological connectivity and DOC, tannin, and condensed aromatics. Specifically, the instantaneous DOC flux increased dramatically when the hydrological connectivity strength exceeded 0.14; tannin and condensed aromatics exhibited a rapid increase with rising connectivity strength, but remained stable at connectivity strength above 0.25. However, hydrological connectivity showed no significant correlation with unstable components (such as lipids, protein, amino sugars, and carbohydrates). These results provide new insights into hydrological controls on the quantity and quality of DOM export and contribute to developing appropriate catchment management strategies for carbon storage.

[External rhinoplasty based on the classification of alar retraction associating with exposure of the nostrils].

Objective: To introduce a classification of alar retraction, and to discuss the therapeutic strategy of alar retraction with cartilage graft and the satisfaction evaluation of patients after operation. Methods: A retrospective analysis was performed on 88 patients with alar retraction admitted to the Department of Plastic and Aesthetic (Burn) Surgery, the Second Xiangya Hospital of Central South University from January 2015 to December 2020, including 20 males and 68 females, aged 20 to 48 years, with an average age of 28.98 years. All patients underwent external rhinoplasty according to a series of treatment plans determined by the classification of alar retraction based on nostril exposure. Visual Analogue Scale (VAS) and Rhinoplasty Outcomes Evaluation (ROE) were used to conduct satisfaction survey before and 12 months after operation. Wilcoxon signed-rank test was used to analyze patient satisfaction. Results: A total of 88 patients were included in this study. According to the classification of alar retraction based on nostril exposure, 45 cases were mild, 23 cases were moderate, and 20 cases were severe. There were 16 cases of unilateral and 72 cases of bilateral alar retraction. The patients were followed up for 12 to 18 months, with an average of 13.37 months. The VAS score and ROE score after each type of surgery were higher than those before surgery, with statistically significant (all P<0.05). Among them, the difference in VAS score (6.75±1.29) and in ROE satisfaction (67.70±7.38) of patients with severe alar retraction were the most significant improvement. Conclusion: The classification of alar retraction based on nostril exposure in the frontal view can comprehensively evaluate the severity of alar retraction, and makes the treatment algorithms systematic and comprehensive. The satisfaction of patients is relatively high.

Molecular cloning and expression analysis of heat shock protein 20 (HSP20) from the pearl oyster Pinctada martensii.

Small heat shock proteins (HSPs) are molecular chaperones with ATP-independent properties. They are involved in a variety of physiological and stress processes. In this study, the full-length HSP 20 (HSP20) from Pinctada martensii, designated as PmHSP20, was obtained from hemocytes using rapid amplification of cDNA ends technology. The PmHSP20 cDNA was 952 bp in length, containing an open reading frame of 534 bp that encoded 177-amino acid residues, with an isoelectric point of 5.86 and molecular weight of 20.24 kDa. The sequence of this deduced polypeptide contained typical structure and function domains conserved in the HSP20 family, providing evidence that PmHSP20 belongs to the HSP20 family. The PmHSP20 mRNA expression levels were detected in various tissues of P. martensii and in hemocytes after challenges with the bacteria Vibrio harveyi and lipopolysaccharide (LPS) using quantitative real-time polymerase chain reaction amplification. The results indicated that PmHSP20 is constitutively expressed in all tissues tested and might be involved in the immune response. The upregulation of PmHSP20 after V. harveyi and LPS challenge suggests that PmHSP20 plays an important role in anti-bacterial immunity. Studies on PmHSP20 are a valuable resource to further explore the immune system in pearl oysters and might enhance our knowledge of molluscan innate immunity.

Molecular characterization and expression analysis of purple acid phosphatase gene from pearl oyster Pinctada martensii.

Purple acid phosphatases (PAPs), also known as type 5 acid phosphatases, are widely present in animals, plants, and fungi. In mammal, PAP was reported to participate in immune defense and bone resorption. In this study, the characteristics and potential functions of a PAP gene from pearl oyster Pinctada martensii (pm-PAP) were examined. The Pm-PAP cDNA was found to be 2777 base pairs, containing a 1581-base pair open reading fragment encoding for 526 amino acids with an estimated molecular mass of 60.1 kDa and theoretical isoelectric point of 5.82. One signal peptide and five conserved motifs [GDXX/GDXXY/GNH(D/E)/XXXH/(A/G)HXH] were present in the entire sequence. Tissue expression profile analysis showed that pm-PAP mRNA was constitutively expressed in all tissues studied with abundant mRNA found in mollusk defense system, including hepatopancreas, gill, and hemocytes. After lipopolysaccharide stimulation, the expression of pm-PAP mRNA in hemocytes was dramatically upregulated at 2 h and achieved the highest level at 36 h. Additionally, pm-PAP mRNA expression was significantly increased and achieved the highest level at 2 days after the surgical implantation during pearl production. These results suggest that pm-PAP is a constitutive and inducible protein that may be involved in the immune defense of pearl oyster.

Molecular cloning and expression analysis of a pearl oyster (Pinctada martensii) heat shock protein 90 (HSP90).

Heat shock protein 90 (HSP90) is an important molecular chaperone required for proper folding of cellular proteins, and thus, it plays an essential role in protecting cells from damage during stress. In this study, an HSP90 cDNA designated PmHSP90 was cloned from the mantle tissue of the pearl oyster Pinctada martensii using reverse transcription polymerase chain reaction (RT-PCR) coupled with the rapid amplification of cDNA ends (RACE) approach. PmHSP90 cDNA was 2584 bp in length, including an open reading frame of 2160 bp, which encodes a polypeptide of 719 amino acid residues, with predicted molecular mass and isoelectric point of 83.0 kDa and 4.87, respectively. Multiple-sequence alignment indicated that HSP90 is highly conserved among species, and PmHSP90 showed 89% sequence identity to Crassostrea gigas HSP90. Five conserved amino acid blocks defined as HSP90 protein family signatures were also observed in PmHSP90, indicating that PmHSP90 may be a cytosolic member of the HSP90 family. Expression levels of PmHSP90 were detected in various tissues of P. martensii and in hemocytes under three different stress conditions using quantitative real-time PCR (qPCR). The results demonstrate that PmHSP90 mRNA is constitutively expressed in all the tested tissues and may be involved in the immune response against thermal stress, lipopolysaccharide stimulation, and nucleus insertion operations. Studies on PmHSP90 are a valuable source to further explore the immune system in pearl oysters during the production of pearls, and may enhance our knowledge of molluscan innate immunity.

Molecular characterization of tumor necrosis factor receptor-associated factor 6 (TRAF6) in pearl oyster Pinctada martensii.

Tumor necrosis factor receptor-associated factor 6 (TRAF6) is a key signaling adaptor molecule for tumor necrosis factor receptor superfamily and Toll-like receptor/interleukin-1 receptor family members. It signals the upstream receptors and is involved in a wide range of biological functions, such as immunity and bone metabolism. In this report, the TRAF6 gene from the pearl oyster Pinctada martensii (designated as PmTRAF6) was identified and characterized. The obtained full-length PmTRAF6 cDNA was 2273 bp, containing a 5'-untranslated region (UTR) of 297 bp, a 3'-UTR of 128 bp with a 42-bp poly (A) tail, and an open reading frame of 1848 bp that encoded 616-amino acid residues. The deduced protein sequence of PmTRAF6 contained a conserved TRAF family motif including a RING-type zinc finger, two TRAF-type zinc fingers, and a coiled-coil region followed by one meprin and TRAF homology domain. Multiple-sequence alignment indicated that TRAF6 was highly conserved among species, and PmTRAF6 showed 53% sequence identity to Azumapecten farreri and Mizuhopecten yessoensis. Furthermore, an amino acid sequence containing a low-complexity region was inserted in the TRAF6s from mollusk. Quantitative real-time polymerase chain reaction analysis demonstrated that PmTRAF6 was constitutively expressed in all tissues studied, with the most abundant mRNA expression in hepatopancreas and gill in P. martensii. After lipopolysaccharide stimulation, the expression of PmTRAF6 mRNA was dramatically upregulated. These results suggested that the obtained PmTRAF6 was a member of the TRAF6 family and perhaps involved in the innate immune response of pearl oyster.

Isolation and characterization of microsatellite DNA loci from the peanut worm, Sipunculus nudus.

Sipunculus nudus, the peanut worm, is the best known species in its genus. This unsegmented subtidal marine worm is consumed in some parts of Asia and is also used as fish bait. We found 20 microsatellite DNA markers for S. nudus. The number of alleles per polymorphic locus ranged from two to seven in a sample of 39 individuals. Observed and expected heterozygosities per polymorphic locus varied from 0.103 to 1.000 and from 0.307 to 0.771, respectively. Five loci showed significant departure from Hardy-Weinberg equilibrium after sequential Bonferroni's correction. No significant linkage disequilibrium between pairs of loci was found. These microsatellite markers will provide useful tools for investigating genetic population structure, population history and conservation management of S. nudus.