Analytical challenges: determination of tetrodotoxin in human urine and plasma by LC-MS/MS

Tetrodotoxin (TTX) is a powerful sodium channel blocker found in puffer fish and some marine animals. Cases of TTX poisoning most often result from puffer fish ingestion. Diagnosis is mainly from patient's signs and symptoms or the detection of TTX in the leftover food. If leftover food is unavailable, the determination of TTX in the patient's urine and/or plasma is essential to confirm the diagnosis. Although various methods for the determination of TTX have been published, most of them are for food tissue samples. Dealing with human urine and blood samples is much more challenging. Unlike in food, the amount of toxin in the urine and blood of a patient is generally extremely low; therefore a very sensitive method is required to detect it. In this regard, mass spectrometry (MS) methods are the best choice. Since TTX is a very polar compound, there will be lack of retention on conventional reverse-phase columns; use of ion pair reagent or hydrophilic interaction liquid chromatography (HILIC) can help solve this problem. The problem of ion suppression is another challenge in analyzing polar compound in biological samples. This review will discuss different MS methods and their pros and cons.     

Production of Oocytes of Nile Tilapia (Oreochromis niloticus) for In Vitro Fertilization via Hormonal Treatments

Only a few studies have described hormonal treatments for induction of synchronicity and gamete collection in Nile tilapia (Oreochromis niloticus), both important for assortative matings in breeding programmes and essential for polyploidy technologies. In this study, we compared the effectiveness of carp pituitary extract (CPE), Nile tilapia pituitary extract (TPE), human chorionic gonadotropin (hCG) and gonadotropin‐releasing hormone (GnRH) protocols on the induction of spawning and egg production in Nile tilapia. Among the hormonal treatments analysed, only hCG was effective for producing viable gametes for in vitro fertilization. To verify the viability of this hormonal treatment, hCG was tested using different doses (1000, 2000, 3000, 4000 and 5000 IU/kg) in a large number of females (208 animals) from two Nile tilapia lines. The results indicated that hCG doses between 1000 and 5000 IU/kg could be used to induce final oocyte maturation in Nile tilapia with collection of stripped oocytes. This is the first study to report differential reproductive responses to hormonal treatment between tilapia lines: line 1 was more efficient at producing eggs and post‐hatching larvae after hCG induction than line 2. In conclusion, we demonstrated that the hCG protocol may be applied on a large scale to induce final oocyte maturation in Nile tilapia. The development of a protocol for in vitro fertilization in Nile tilapia may aid in breeding programmes and biotechnological assays for the development of genetically modified lines of Nile tilapia.     

ECONOMIC FEASIBILITY OF SMALL-SCALE BLACK-LIPPED PEARL OYSTER (PINCTADA MARGARETIFERA) PEARL FARMING IN THE CENTRAL PACIFIC

ABSTRACT

This work provides an analysis of the economic feasibility of one of many small-scale aquaculture operations being considered, black pearl oyster farms, as one type of supplemental economic activity for outer island communities in the Central Pacific. Specifically, projections of financial performance of a small-scale 25,000 seeded pearl oyster farm using the Tahitian long-line method are being conducted. Estimates of initial capital investment and annual operating costs are being formulated, an annual cash flow and enterprise budget are being developed. Results show that initial capital investment is $202,076. Annual operating expenses are $293,726 during full operation. The largest costs contributing to annual operating expenses are seeding (46%), labor including farm owner's opportunity cost (24%), and depreciation (9%). The base model presented in this work suggests profitability over a 20-year horizon.

Net returns over a 20-year farm horizon based on an 8% discount rate indicate a positive NPV of $ 102945. Sensitivity analysis on profit due to the variability of market price, survival, and cost of seed and other inputs are conducted and results presented.     

Effects of meiotic inhibitors and gonadotrophins on porcine oocytes in vitro maturation,fertilization and development

This study evaluated the effect of three reversible meiotic inhibitors (MINs) and their interaction with gonadotrophins (Gns) on the meiotic maturation and developmental competence of porcine oocytes. In experiment 1, the oocytes were matured for 22 hr in the presence or absence of dbcAMP (1 mM), cycloheximide (7 μM) or cilostamide (20 μM) with or without Gns, and for an additional 22 hr in the absence of MINs and Gns. At 22 hr of maturation, regardless of the presence of Gns, a higher proportion (p < .001) of oocytes cultured in the presence of MINs were effectively arrested at the germinal vesicle stage compared with the oocytes cultured without MINs. At 44 hr of maturation, the proportion of oocytes that reached MII was higher (p < .05) in groups with Gns compared with groups without Gns. In experiment 2, oocytes that were matured as in experiment 1 were inseminated and cultured for 7 days to evaluate fertilization parameters and blastocyst formation. Only oocytes from the dbcAMP + Gns group had higher (p < .05) efficiency of fertilization compared with the other treatment groups. The presence of dbcAMP during maturation also increased (p < .05) blastocyst formation and efficiency of blastocyst formation in both the presence and absence of Gns. These results indicate that the interaction of Gns with the tested MINs improved meiotic progression. In addition, regardless of supplementation with Gns, the presence of dbcAMP during the first maturation period increased and even doubled the capacity of oocytes to develop to the blastocyst stage.     

海原试区土壤资源及其培肥改良

从分析区域气候条件、地貌基础、成土母质、植被和人类活动等成土因素入手，探讨了海原试区土壤形成的基本过程、类型划分和分布规律，论述了主要土壤的性态特征，提出区域土壤培肥改良的关键措施。     

A new phenolic glucoside from the leaves of Heliciopsis lobata

A new phenolic glucoside ester, 6'-E-(2'-methyl-2'-butenoyl) arbutin (1), was isolated from the leaves of Heliciopsis lobata. Its structure was elucidated by spectral analysis.     

构建与社会主义新农村建设相适应的农村金融体系

当前,社会主义新农村建设,一方面带来了越来越大的农村金融需求,另一方面也凸显了农村金融需求与供给之间的诸多矛盾。本文建议,要从建立多层次、竞争性的农村金融机构体系,分类指导农村信用社改革,推动农村民间金融合法发展,加大政府对农村金融的扶持力度等方面着手,构建与社会主义新农村建设相适应的农村金融体系。     

Response of bovine and porcine peripheral blood mononuclear cells to human recombinant interleukin 2(125)

Bovine and porcine peripheral blood mononuclear cells (PBMC) were tested for their response to human recombinant interleukin 2(125) (rIL 2(125)). The rIL 2(125) used in these experiments was purified to homogeneity from Escherichia coli, contained a site-specific modification at amino acid #125 replacing a cysteine with a serine residue and had a specific activity of 4 X 10(6) units/mg. Human rIL 2(125) was shown to be directly mitogenic for bovine and porcine PBMC and was able to maintain the long-term growth of mitogen-activated PBMC of both species. Long-term cultures were highly sensitive to low levels of rIL 2(125) and showed dose-dependent responses when used in short-term IL 2 assays. Bovine and porcine PBMC preincubated with human rIL 2(125) for 1 and 5 days demonstrated enhanced levels of cell-mediated cytotoxicity against both allogeneic and xenogeneic cell lines.     

大豆蛋白水解物水解度测定的研究

利用茚三酮显色法及甲醛滴定法对大豆蛋白水解物的水解度进行测定并进行了结果比较，结果表明二法是一致的．蛋白质水解度的测定将为蛋白质酶水解程度的控制提供必要的方法．