Publications by authors named "Qin-Qing Wang"

8 Publications

  • Page 1 of 1

A novel thermoanalytical method for quantifying microplastics in marine sediments.

Sci Total Environ 2021 Mar 9;760:144316. Epub 2020 Dec 9.

Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai 519000, China. Electronic address:

Microplastic pollution in marine environments is of particular concern on its risk to the ecosystem. To assess and manage microplastic contaminants, their quantitative detection in environmental samples is a high priority. However, uncertainties of current methods still exist when estimating their abundances, particularly with fine-grained (<1 mm) microplastics. This work reports a novel thermoanalytical method for quantifying microplastics by measuring the contents of microplastic-derived carbon (MPC) in samples under the premise of nearly eliminating the limit of their particle appearances. After validating the method via samples with the spiked microplastics, we have conducted a case study on sediment core H43 that spanned 1925-2009 CE from the Yellow Sea for further illustrating the high reliability and practicability of this method for quantifying microplastics in natural samples. Our results have demonstrated that the proposed method may be a promising technique to determine the mass-related concentrations of the total microplastics in marine sediments for evaluating their pollution status and quantitative contribution to marine carbon storage.
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http://dx.doi.org/10.1016/j.scitotenv.2020.144316DOI Listing
March 2021

Evaluation of ergosterol composition and esterification rate in fungi isolated from mangrove soil, long-term storage of broken spores, and two soils.

Appl Microbiol Biotechnol 2020 Jun 24;104(12):5461-5475. Epub 2020 Apr 24.

Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Marine Sciences, Sun Yat-Sen University, Zhuhai, 519082, People's Republic of China.

Ergosterol is an important fungal-specific biomarker, but its use for fungal biomass estimation is still varied. It is important to distinguish between free and esterified ergosterols, which are mainly located on the plasma membrane and the cytosolic lipid particles, respectively. The present study analyzes free and esterified ergosterol contents in: (1) the fifty-nine strains of culturable fungi isolated from mangrove soil, (2) the broken spores of the fungus Ganoderma lucidum stored in capsule for more than 12 years, and (3) the mangrove soil and nearby campus wood soil samples by high performance liquid chromatography (HPLC). The results show that the contents of free and esterified ergosterols varied greatly in fifty-nine strains of fungi after 5 days of growth, indicating the diversity of ergosterol composition in fungi. The average contents of free and total ergosterols from the fifty-nine strains of fungi are 4.4 ± 1.5 mg/g and 6.1 ± 1.9 mg/g dry mycelia, respectively, with an average ergosterol esterification rate of 27.4%. The present study suggests that the fungi might be divided into two classes, one is fungi with high esterification rates (e.g., more than 27%) such as Nectria spp. and Fusarium spp., and the other is fungi with low esterification rates (e.g., less than 27%) such as Penicillium spp. and Trichoderma spp. Moreover, the ergosterol esterification rate in the spores of G. lucidum is 91.4% with a very small amount of free ergosterol (0.015 mg/g), compared with 41.9% with a higher level of free ergosterol (0.499 mg/g) reported in our previous study in 2007, indicating that free ergosterol degrades more rapidly than esterified ergosterol. In addition, the ergosterol esterification rates in mangrove soil and nearby campus wood soil samples range from 0 to 39.0%, compared with 80% in an old soil organic matter reported in a previous study, indicating the potential relationship between aging degree of fungi or soil and esterification rate. The present study proposes that both free and esterified ergosterols should be analyzed for fungal biomass estimation. When the ergosterol esterification rates in soils are higher, free ergosterol might be a better marker for fungal biomass. It is speculated that the ergosterol esterification rate in soils might contain some important information, such as the age of old-growth forests over time scales of centuries to millennia, besides the senescence degree of fungal mycelia in soils. KEY POINTS: • Fungi might be divided into two classes depending on ergosterol esterification rates. • Ergosterol esterification rate of broken spores stored for long time raised evidently. • Both free and esterified ergosterols should be analyzed for fungal biomass estimate. • Free ergosterol is a better marker for fungal biomass with a high esterification rate.
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http://dx.doi.org/10.1007/s00253-020-10601-3DOI Listing
June 2020

Characterization of Matrix Metalloprotease-9 Gene from Nile tilapia () and Its High-Level Expression Induced by the Challenge.

Biomolecules 2020 01 3;10(1). Epub 2020 Jan 3.

Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-Sen University, Guangzhou 510006, China.

The bacterial diseases of tilapia caused by have resulted in the high mortality and huge economic loss in the tilapia industry. Matrix metalloproteinase-9 (MMP-9) may play an important role in fighting infection. However, the role of MMP-9 in Nile tilapia against is still unclear. In this work, MMP-9 cDNA of Nile tilapia () has been cloned and characterized. has 2043 bp and encodes a putative protein of 680 amino acids. NtMMP-9 contains the conserved domains interacting with decorin and inhibitors via binding forces compared to those in other teleosts. Quantitative real-time-polymerase chain reaction (qPCR) analysis reveals that NtMMP-9 distinctly upregulated following infection in a tissue- and time-dependent response pattern, and the tissues, including liver, spleen, and intestines, are the major organs against a infection. Besides, the proteolytic activity of NtMMP-9 is also confirmed by heterologous expression and zymography, which proves the active function of NtMMP-9 interacting with other factors. The findings indicate that NtMMP-9 was involved in immune responses against the bacterial challenge at the transcriptional level. Further work will focus on the molecular mechanisms of NtMMP-9 to respond and modulate the signaling pathways in Nile tilapia against invasion and the development of NtMMP-9-related predictive biomarkers or vaccines for preventing bacterial infection in the tilapia industry.
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http://dx.doi.org/10.3390/biom10010076DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7023376PMC
January 2020

Efficient Conversion of Cane Molasses Towards High-Purity Isomaltulose and Cellular Lipid Using an Engineered Strain in Fed-Batch Fermentation.

Molecules 2019 Mar 28;24(7). Epub 2019 Mar 28.

Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-Sen University, Guangzhou, Guangdong 510006, China.

Cane molasses is one of the main by-products of sugar refineries, which is rich in sucrose. In this work, low-cost cane molasses was introduced as an alternative substrate for isomaltulose production. Using the engineered lipolytica, the isomaltulose production reached the highest (102.6 g L¹) at flask level with pretreated cane molasses of 350 g L¹ and corn steep liquor of 1.0 g L¹. During fed-batch fermentation, the maximal isomaltulose concentration (161.2 g L¹) was achieved with 0.96 g g¹ yield within 80 h. Simultaneously, monosaccharides were completely depleted, harvesting the high isomaltulose purity (97.4%) and high lipid level (12.2 g L¹). Additionally, the lipids comprised of 94.29% C and C fatty acids, were proved suitable for biodiesel production. Therefore, the bioprocess employed using cane molasses in this study was low-cost and eco-friendly for high-purity isomaltulose production, coupling with valuable lipids.
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http://dx.doi.org/10.3390/molecules24071228DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6480463PMC
March 2019

Relationship between β-d-fructofuranosidase activity, fructooligosaccharides and pullulan biosynthesis in Aureobasidium melanogenum P16.

Int J Biol Macromol 2019 Mar 20;125:1103-1111. Epub 2018 Dec 20.

College of Marine Life Sciences, Ocean University of China, Yushan-Road, No. 5, Qingdao, China; Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Yushan Road, No. 5, Qingdao 266003, China. Electronic address:

It has been thought that when different strains of Aureobasidium spp. were grown in sucrose, the produced fructooligosaccharides (FOSs) by β-d-fructofuranosidase were beneficial for their cell growth and pullulan biosynthesis. However, it is still unknown about how β-d-fructofuranosidases activity and synthesized FOSs influence on pullulan biosynthesis. It was found that the genomic DNA of Aureobasidium melanogenum P16, a high pullulan producing yeast, contained three genes encoding β-d-fructofuranosidase1, β-d-fructofuranosidase2 and β-d-fructofuranosidase3. The FTR1 factor, a transcriptional activator, activated expression of the three β-d-fructofuranosidase genes and invertase gene. Disruption of the FTR1 gene rendered a disruptant DF3 to produce less FOSs (12.1 ± 0.4 g/L), less β-d-fructofuranosidase activity (1.1 ± 0.2 U/mL), lower Mw (3.8 × 10) of the pullulan and more pullulan titer (77.0 ± 2.6 g/L) than the yeast strain P16. Similarly, removal of both the two genes encoding β-d-fructofuranosidase1 and β-d-fructofuranosidase3 resulted in a double mutant DF4-7 producing 77.5 ± 3.1 g/L pullulan with Mw of 3.4 × 10, 0.2 ± 0.0 U/mL of β-d-fructofuranosidase activity and the trace amount of FOSs while its wild type strain P16 yielded 65.7 ± 3.5 g/L pullulan with Mw of 4.4 × 10, 6.8 ± 0.0 U/mL of β-d-fructofuranosidase activity and 6.2 ± 0.5 g/L of FOSs. These confirmed that high β-d-fructofuranosidase activity, the presence of high level of FOSs negatively influenced pullulan biosynthesis, but positively increased Mw of the produced pullulan. However, the β-d-fructofuranosidase2 had no such function. Furthermore, complementation of the FTR1 gene, β-d-fructofuranosidase1 gene and β-d-fructofuranosidase3 gene enabled the corresponding transformants to restore β-d-fructofuranosidase activity, FOSs and pullulan biosynthesis and Mw of the pullulan.
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http://dx.doi.org/10.1016/j.ijbiomac.2018.12.141DOI Listing
March 2019

Simultaneous production of both high molecular weight pullulan and oligosaccharides by Aureobasdium melanogenum P16 isolated from a mangrove ecosystem.

Int J Biol Macromol 2017 Sep 29;102:1016-1024. Epub 2017 Apr 29.

College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China. Electronic address:

After the compositional change of a pullulan production medium, a molecular weight (Mw) of the pullulan produced by Aureobasidium melanogenum P16 was 2.32×10 and a pullulan titer was 44.4g/L while a Mw of the pullulan produced by A. melanogenum P16 grown in the initial medium was only 3.47×10 and a pullulan titer was 65.3g/L. The increased Mw of the pullulan was due to the decreased activities of α-amylase, glucoamylase and pullulanase while the decreased pullulan titer was related to the decreased transcriptional levels of the genes encoding 6-P-glucose kinase, glucosyltransferase, α-phosphoglucose mutase, UDPG-pyrophosphorylase and pullulan synthetase. During the 10-L fermentation, when the yeast strain P16 was grown in the initial medium, the pullulan and oligosaccharide titers were 65.5g/L and 7.8g/L, respectively and the Mw of the produced pullulan was 4.42×10 while when the yeast strain P16 was grown in the compositionally changed medium, the pullulan and oligosaccharide titers were 46.4g/L and 27.8g/L, respectively and the Mw of the produced pullulan was 2.6×10. Most of the oligosaccharides produced by the yeast strain P16 cultivated in the compositionally changed medium had degree of polymerization of 4 and 5. Therefore, both of the high Mw pullulan and oligosaccharides with high levels were produced by the yeast strain P16.
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http://dx.doi.org/10.1016/j.ijbiomac.2017.04.057DOI Listing
September 2017

A glycosyltransferase gene responsible for pullulan biosynthesis in Aureobasidium melanogenum P16.

Int J Biol Macromol 2017 Feb 23;95:539-549. Epub 2016 Nov 23.

College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China. Electronic address:

In this study, one of the glucosyltransferase genes for pullulan production was cloned from Aureobasidum melanogenum P16 and charaterized. It was found that the UGT1 gene had 4774bp with four introns (47, 52, 54 and 46bp). The N-terminal part of the protein displayed a conserved sequence controlling both sugar donor and accepter for substrate specificity whereas its C-terminal part carried a DXD motif that coordinated donor sugar binding. After complete removal of the gene UGT1, the mutant 1152-3 still produced 27.7±3.1g/L of pullulan and 4.6U/g of the specific glucosyltransferase activity while its wild type strain P16 yielded 63.38±2.0g/L of pullulan and 5.7U/g of the specific glucosyltransferase activity. However, after overexpression of the gene UGT1, the transformant G63 could produce 78.0±3.01g/L of pullulan and 19.0U/g of the specific glucosyltransferase activity. It is interesting to note that the molecular weight of the produced pullulan by the wild type strain was 4.6×10 while that of the produced pullulan by the transformant G63 was 6.2×10. During the 10-Litter fermentation, the pullulan titer produced by the transformant G63 reached 80.2±2.0 g/L within 132h.
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http://dx.doi.org/10.1016/j.ijbiomac.2016.11.081DOI Listing
February 2017

CreA is directly involved in pullulan biosynthesis and regulation of Aureobasidium melanogenum P16.

Curr Genet 2017 Jun 15;63(3):471-485. Epub 2016 Sep 15.

College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China.

Aureobasidium melanogenum P16 is a high pullulan-producing yeast. However, glucose repression on its pullulan biosynthesis must be relieved. After the gene encoding a glucose repressor was cloned, characterized and analyzed, it was found that the repressor belonged to one member of the CreA in filamentous fungi, not to one member of the Mig1 in yeasts. After the CREA gene was fully removed from the yeast strain P16, the glucose repression in the disruptant DG41 was relieved. At the same time, the pullulan production by the disruptant DG41 was enhanced compared to that by its wild-type strain P16, and the transcriptional levels of the gene encoding a glucosyltransferase, three genes encoding glucose transporters, the gene encoding a 6-P-glucose kinase and the genes encoding α-amylase, glucoamylase and pullulanase in the disruptant DG41 were also promoted. However, the transcriptional levels of the genes encoding the CreA and another two glucose transporters were greatly reduced. During the 10-liter fermentation, the disruptant DG41 produced 64.93 ± 1.33 g/l pullulan from 120 g/l of glucose, while its wild-type strain P16 produced only 52.0 ± 1.95 g/l pullulan within 132 h. After the CREA gene was complemented in the disruptant D373, the pullulan production by the transformant BC4 was greatly reduced compared to that by its wild-type strain P16, and the transcriptional levels of the many genes in the transformant BC4 were also decreased. All the results confirmed that the CreA played an important role in the regulation of pullulan biosynthesis in A. melanogenum P16, and that glucose derepression on pullulan biosynthesis could improve pullulan production from glucose. This study opened the possibility for improving the industrial production of this exopolysaccharide by genetic engineering.
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http://dx.doi.org/10.1007/s00294-016-0650-yDOI Listing
June 2017