[Carbon dioxide fluxes at the water-air interface and the main influencing factors from diffe-rent aquaculture systems of Sebastes schlegelii and Chlamys farreri]. / ä¸åŒè®¸æ°å¹³é®‹ä¸Žæ ‰å­”æ‰‡è´å »æ®–ç³»ç»Ÿæ°´-气界面CO2é€šé‡åŠå ¶ä¸»è¦å½±å“å› å­.

The static chamber-gas chromatography method was applied to observe CO2 fluxes across the water-air interface from different aquaculture systems, including four groups of mesocosms, i.e., blank control system (CK), monoculture system of Sebastes schlegelii (F), monoculture system of Chlamys farreri (B) and polyculture system of S. schlegelii and C. farreri (FB). Meanwhile, the physical, chemical and biological indices of the water were measured. The results showed that the group CK was a stable CO2 source, with the mean flux of 12.42 mg·m-2·h-1. The group B was a CO2 source during the early and middle periods of the experiment and a CO2 sink at the end of the experiment, with the mean flux during the experiment being 10.95 mg·m-2·h-1. The change trends of CO2 flux in the group F and FB were generally consistent, acting as CO2 sources in the early period and as CO2 sinks subsequently. The mean fluxes of those two groups during the expe-riment were -3.53 and -10.49 mg·m-2·h-1, respectively. Water pH was a good predictor for CO2 flux across the water-air interface according to the result of regression analysis, with pH value of 8.25 as the critical threshold between efflux and influx. The net primary production of water column was the main factor influencing the CO2 flux, indicating that phytoplankton might be the main internal force regulating the CO2 flux across the water-air interface. Our results indicated that C. farreri at present stocking density in the polyculture system could promote phytoplankton biomass as well as primary production and therefore enhance the CO2 sink function.

Risk factor analysis of recurrent hepatocellular carcinoma with portal vein tumor thrombus / 中国实用外科杂志

OBJECTIVE: To investigate the effect of clinicopathological factors on the recurrent hepatocellular carcinoma(HCC)with portal vein tumor thrombus(PVTT)after radical resection.METHODS: The data of patients with HCC who underwent radical resection between January 2000 and December 2014 in Affiliated Hospital of Qingdao University were analyzed retrospectively.Clinical and pathological data from first resection to the recurrence of HCC with PVTT were extracted in the form of data tables.All patients were divided into PVTT group and non PVTT group according to the occurence of PVTT at time of HCC recurrence,and the risk factors of PVTT formation were analyzed.Risk factors influencing the formation time,from radical resection to HCC recurrence,were analyzed in recurrent HCC patients with PVTT.RESULTS: Univariate analysis results showed that patients having HCC with multiple tumors,no tumor capsule,and Child-pugh B grade had a high proportion of PVTT when HCC recurred.The results of logistic regression analysis showed that multiple tumors,no tumor capsule,and Childpugh B grade were independent risk factors for PVTT formation after radical resection of HCCA predictive model was established on the basis of the three risk factors(1 point for each factor).ROC curve showed the total model score has certain predictive value.The area under the curve was 0.662(P=0.003,95% CI:0.557-0.766),cut-off value was 0.5 points,Youden index was 0.302(sensitivity=60.0%,specificity=70.2%).The higher the model score,the shorter the tumor-free survival time(P=0.007),and the higher the incidence of PVTT recurrence(P=0.001).The results of Kaplan-Meier(log-rank test)and multivariate analysis of Cox regression model showed that lower differentiation of HCC was an independent risk factor influencing the time from radical resection to HCC recurrence with PVTT(P=0.000). CONCLUSION: Patients with multiple tumor foci,no tumor capsule and Child grade B grade liver cancer are more likely to recur with PVTT after RO operation.And among them,the low differentiation of liver cancer grows faster.A closer follow-up or preventive treatment of patients with high-risk factors may improve prognosis.

[Seasonal variation of functional diversity of aquatic microbial community in Apostichopus japonicus cultural pond].

The functional diversity of aquatic microbial communities in sea cucumber (Apostichopus japonicus) cultural ponds was examined in this paper. The Biolog plate technique and redundancy analysis (RDA) method were used to evaluate seasonal changes and their relationships with environmental factors. The results showed that both total amount and types of carbon sources utilized by microbes in the sea cucumber cultural ponds varied seasonally, and were the highest in summer and lowest in winter, with polymers being the main type of carbon sources. Principal component analysis revealed that the carbon utilization diversity of the microbial communities varied significantly over the seasonal courses. A total of 10 categories of carbon sources were significantly related to the principal component 1, among which were polymers, carbohydrates, carboxylic acids, amino acids, and amines. Significant seasonal changes were detected for all carbon utilization diversity indices of the microbial communities, including Shannon, McIntosh, Simpson, and S-E. However, seasonal variations were different among the microbial diversity indices. RDA analysis revealed that TP, NO(3-)-N, TN, and PO4(3-)-P were the critical environmental factors influencing the seasonal changes in functional diversity of aquatic microbial community in sea cucumber cultural ponds.

Development of a monoclonal antibody-based sandwich-type enzyme-linked immunosorbent assay (ELISA) for detection of abrin in food samples.

Abrin is a plant toxin, which can be easily isolated from the seeds of Abrus precatorius. It may be used as a biological warfare agent. In order to detect abrin in food samples, a two-layer sandwich format enzyme-linked immunosorbent assay based on the monoclonal antibody (mAb) (as capture antibody) and rabbit polyclonal serum (as detecting antibody) was developed and applied for the determination of abrin in some food matrices. The linear range of the mAb was 1-100 µg L(-1) with a detection limit of 0.5 µg L(-1) for abrin in phosphate buffered saline (PBS). The recoveries of abrin from sausage, beer and milk samples ranged 97.5-98.6%, 95.8-98.4% and 94.8-9.6%, respectively, with a coefficient of variation (CV) of 3.7% or less. The newly developed sandwich ELISA using the mAb appears to be a reliable and useful method for detection of abrin in sausage, beer and milk.

Monoclonal antibody based inhibition ELISA as a new tool for the analysis of melamine in milk and pet food samples.

Stories of recent cases about melamine misuse to raise the false impression of a high protein content of milk in China emerged in September of 2008, have become an international health event. To meet the need for rapid and reliable monitoring of melamine in milk samples, a monoclonal antibody (mAb) was produced and an inhibition enzyme-linked immunosorbent assay (ELISA) was developed based on the mAb. The standard curve was linear in the range from 0.03 to 9 ng mL(-1) with a detection limit (LOD) of 0.01 ng mL(-1). The sensitivity of the assay was 0.35 ng mL(-1). The average recovery values of melamine in the liquid milk, powder milk, dog food and cat food were 99%, 96%, 9% and 98%, respectively and the coefficient of variation (CV) values of all samples were less than 10%. The obtained results showed a potential method as a tool for the rapid and reliable monitoring of melamine in liquid milk and milk powder samples (158 words).

Development of a multi-component chemically reactive detection conjugate for the determination of Hg(II) in water samples.

Mercury ions (Hg(II)) are considered highly toxic and hazardous element even at low levels. The contamination of Hg(II) is a global problem. To develop selective and sensitive technique for the detection of Hg(II) has attracted considerable attention. In this study, a multi-component chemically reactive detection conjugate for determination of Hg(II) has been synthesized and a competitive format assay was proposed. In the technique, the chemically reactive capture conjugate was coated on the plate. The reactive detection conjugate was then captured by the capture conjugate. TMB solution was added and catalyzed by HRP molecules immobilized on AuNPs. Finally, the developed enzymatic signal was measured at 450 nm. The linear range of the assay was 0.35-350 ppb with a detection limit of 0.1 ppb. The average recoveries of Hg(II) from mineral water, tap water and lake water were 100.03%, 103.13% and 102.03%, respectively. All coefficients of variation (CVs) were less than 10%. The results are closely correlated with those from inductively coupled plasma mass spectrometry (ICP-MS), which indicated that the developed technique is a reliable method for and sensitive detection of Hg(II) in water samples.

A versatile and highly sensitive probe for Hg(II), Pb(II) and Cd(II) detection individually and totally in water samples.

The detection of heavy metal ions using enzyme-linked immunosorbent assays (ELISA) has been reported by several research groups. However, highly sensitive and selective detection of total heavy metal ions using ELISA is a major technical limitation. Here we describe the development of a versatile and highly sensitive probe combining goat anti-mice IgG, colloidal gold nanoparticles (AuNPs) and horseradish peroxidase (HRP). We demonstrate the utility of this probe using three kinds of heavy metal complete antigens and three monoclonal antibodies (McAbs) in one ELISA system to establish a high-throughput screening protocol. The procedure was successfully applied to analysis of Hg(II), Pb(II) and Cd(II) individually and totally from different water samples. The sensitivities for the detection of Hg(II), Pb(II) and Cd(II) individually and totally are 27.4, 3.9, 15.8 and 18.2 nM, respectively. And all limit of detection (LODs) are lower than 1.2 nM. The recovery results obtained from the developed technique showed a good correlation (R(2)=0.983) with those from ICP-MS. The major advantage of the probe is the versatility and high sensibility. The probe could be potentially used, upon demand, as a sensitive and versatile detector for a broad range of applications.

An enhanced ELISA based on modified colloidal gold nanoparticles for the detection of Pb(II).

A novel probe based on colloidal gold nanoparticles (AuNPs) modified with goat anti-mouse IgG and horseradish peroxidase (HRP) was synthesized and an enhanced enzyme-linked immunosorbent assay (ELISA) based on the probe was developed. In the assay, the synthesized probe is bound with a monoclonal antibody (McAb) which is competitively bound by coated BSA-ITCBE-Pb(II) on plate and Pb(II) in samples. The HRP, used here for signal amplification catalytically oxidize the substrate and generate optical signals that is related to the concentration of Pb(II) and can be measured spectrophotometrically. For the monodisperse AuNPs having high surface areas, it can be conjugated with more amount of HRP than that of IgG. Therefore, compared with traditional ELISA, the signal amplification of catalytically oxidized substrate was enhanced. The detection limit for this novel modified AuNPs probe-based assay was 9 pg mL(-1). The recoveries obtained by standard Pb(II) addition to real samples, including a commercial mineral water, tap water, and lake water were all from 94.9% to 102.9%. And the coefficient of variation (CV) value of all samples was less than 10%. The results indicated that the enhanced assay gave higher sensitivity and reliable reproducibility. It could provide a general detection format for low-molecular weight contaminants.

Assessment of the role of brine shrimp Artemia in white spot syndrome virus (WSSV) transmission.

Challenge tests with Artemia four different development stages (nauplii, metanauplii, pseudoadults and adults) to white spot syndrome virus was carried out by immersion challenge and virus-phytoplankton adhesion route in order to asses the possibility of Artemia acting as a vector of WSSV to penaeid shrimp Litopenaeus vannamei postlarvae. The WSSV succeeded in infecting four stages Artemia, and nested-PCR detection for WSSV revealed positive results to virus-phytoplankton adhesion route. No mass mortalities were observed in penaeid shrimp postlarvae fed with WSSV-positive Artemia which exposed to WSSV by virus-phytoplankton adhesion route, whereas WSSV DNA detected in penaeid shrimp postlarvae by nested-PCR. By contrary, no WSSV-positive was detected in any animal fed with WSSV-negative Artemia. These results indicated that Artemia could serve as a vector in WSSV transmission.

Gilvimarinus chinensis gen. nov., sp. nov., an agar-digesting marine bacterium within the class Gammaproteobacteria isolated from coastal seawater in Qingdao, China.

A taxonomic study was performed on strain QM42(T), which was isolated from coastal seawater from an aquaculture site near Qingdao, China. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain QM42(T) was a member of the class Gammaproteobacteria. Cells of strain QM42(T) were Gram-negative, yellow, aerobic and rod-shaped. The strain formed a distinct phyletic line with less than 91 % 16S rRNA gene sequence similarity to its closest relatives with validly published names within the class Gammaproteobacteria. The genomic DNA G+C content was 51.9 mol%. The major fatty acids were C(16 : 1)omega7c/iso-C(15 : 0) 2-OH, C(18 : 1)omega7c and C(16 : 0). Based on data from a polyphasic chemotaxonomic, physiological and biochemical study, strain QM42(T) is considered to represent a novel genus and species, for which the name Gilvimarinus chinensis gen. nov., sp. nov., is proposed. The type strain is QM42(T) (=CGMCC 1.7008(T)=DSM 19667(T)).

[Effects of temperature and light intensity on the growth and biochemical composition of Sargassum thunbergii].

A two-factorial experiment was designed to study the effects of temperature (10, 15, 20, and 25 degrees C) and light intensity (20, 60, 100, 140, and 180 microE x m(-2) x s(-1)) on the growth and biochemical composition of Sargassum thunbergii. The results showed that temperature, light intensity, and their interactions had significant effects on the growth of S. thunbergii. A higher growth rate of S. thunbergii was observed at 15 degrees C - 20 degrees C, and, with the increase of temperature, the light intensity for the maximum growth rate of S. thunbergii had an increasing trend. At 10 degrees C and 15 degrees C, higher light intensity had definite inhibition effect on the growth of S. thunbergii; while at 20 degrees C and 25 degrees C, the growth rate was generally increased with increasing light intensity. Both temperature and light intensity had significant effects on the chlorophyll a and fucoxanthin contents of S. thunbergii, and the effects of light intensity was greater than those of temperature. In general, the chlorophyll a and fucoxanthin contents of S. thunbergii decreased significantly with increasing light intensity but increased with increasing temperature. The carbohydrate content of S. thunbergii increased with increasing light intensity, while no significant difference was observed at different temperature. The protein content of S. thunbergii decreased with increasing light intensity, and was higher at 10 degrees C and 15 degrees C but tented to decrease with increasing temperature. The variation of light intensity and temperature induced the changes in the biochemical composition of S. thunbergii, and these changes could be an active physiological adjustment for the adaptation to the variation of environmental factors, which was of ecological significance to the growth and survival of S. thunbergii.

Bioassay evidence for the transmission of WSSV by the harpacticoid copepod Nitocra sp.

White Spot Syndrome Virus (WSSV) is now one of the most devastating and virulent viral agents threatening the penaeid shrimp culture industry and has been responsible for serious economic losses for shrimp farms worldwide. One remarkable characteristic of WSSV is its wide reservoir range, which contributes to its wide geographical distribution. Among epizootiological surveys, there is substantial evidence for WSSV-positive copepods found in shrimp farming ponds. Therefore, copepods are suspected to be the vector of WSSV. In the present study, nested-PCR analysis showed positive results in the harpacticoid copepod Nitocra sp. exposed to WSSV by virus-phytoplankton adhesion route. Oral route and intramuscular injection were used to test the pathogenicity of WSSV isolated from the WSSV-positive Nitocra sp. For the oral route of infection, Marsupenaeus japonicus postlarvae were fed with WSSV-positive copepods. The shrimp postlarvae in the infected treatment became WSSV-positive and occurred 52.50+/-5.00% mortality which was significant higher (P <0.05) than that in the control treatment (20.00+/-0.00%) when postlarvae were fed with WSSV free copepods. In the intramuscular injection challenge, M. japonicus juveniles were injected with the copepods inoculum extracted from the WSSV-positive Nitocra sp., and showed 72.50+/-9.57% mortality which was also significant higher (P <0.05) than that in the control treatment (22.50+/-5.00%) when juveniles were received mock injection of a tissue homogenate prepared from WSSV-negative Nitocra sp. Based on these laboratory challenge studies, it was confirmed that the copepods can serve as a vector in WSSV transmission.