不同金属盐组合腌制无铅皮蛋及其金属含量的测定

采用硫酸铜、硫酸锌、硫酸铁和硫酸镁代替氧化铅配制辅料用来腌制无铅皮蛋;为了寻求这几种元素的最优组合和合理的用量,采用了正交实验方法;通过对实验结果的多指标加权分析法分析,得出四种金属盐对皮蛋腌制影响程度大小顺序依次为:硫酸铜>硫酸锌>硫酸铁>硫酸镁,其中硫酸铜和硫酸铁对实验影响较大,硫酸镁对实验基本无影响;各成分的合理的用量为:MgSO4.5H2O3.5g,FeSO4.7H2O2.0g,CuSO4.5H2O1.0g,ZnSO4.7H2O2.0g。     

Isolation of enterocin SE-K4-encoding plasmid and a high enterocin SE-K4 producing strain of Enterococcus faecalis K-4

Enterococcus faecalis K-4, which produces a class IIa bacteriocin, enterocin SE-K4, carries two plasmids, pEK4S (approximately 60 kb) and pEK4L (approximately 75 kb). Plasmid-curing experiments showed that pEK4S was involved in the production of and immunity to enterocin SE-K4 in strain K-4. A derivative strain, M6, with pEK4S produced a higher amount of enterocin SE-K4 than the parental strain K-4, although its growth rate was lower than that of parental strain K-4. Phenotypic changes in strain M6 are attributed to an increase in plasmid copy number.     

富硒乳酸菌对肝损伤大鼠免疫细胞功能活动的调节作用研究

目的探讨富硒乳酸菌对CCl4诱导肝损伤大鼠的免疫调节和保护机制。方法：选用80只健康成年大鼠，随机分成对照组(C组)、CCh组、CCl4-低剂量富硒乳酸菌制剂保护组(CCl4-LSe组)，CCl4-高剂量富硒乳酸菌制剂保护组(CCl4-HSe组)，通过隔日腹腔注射CCl4诱发肝损伤，连续4w。结果：整个实验期内，富硒乳酸菌制剂能显著提高肝损伤a组织匀浆GSH—Px活性；CCl4组肝组织匀浆MDA含量显著升高，而CCl4-LSe和CCl4-HSe组与C组接近；CCl4-LSe和CCl4-HSe组RBC-CR1花环率均较CCl4组高或显著高；CCl4组RBC—IC花环率显著上升，而EEl4-LSe和CCl4-HSe组与C组接近，明显低于CCl4组；CCl4-LSe和CCl4-HSe组T-淋巴细胞(％)与C组差异不显著，而CCl4组下降明显，B-淋巴细胞(％)与T-淋巴细胞(％)变化相反；CCl4组血液和脾脏NK细胞活性均显著低于C组，而CCl4-LSe和CCl4-HSe组均高于CCl4组，与C组比较差异不显著。结论：富硒乳酸菌制剂可能通过抗损伤保护，干预肝损伤脂质过氧化反应，改善和提高免疫细胞功能活动发挥正常有效的作用。     

混菌发酵玉米秸秆基质蛋白质含量及木质素酶活性的研究

与平菇单菌发酵相比,玉米秸秆经平菇与产朊假丝酵母混菌固态发酵后,其基质粗蛋白含量由8.13%提高到13.41%。为进一步提高混菌固态发酵玉米秸秆基质的粗蛋白含量及木质素酶系的活性,在基础培养基中分别添加豆渣(2%、3%、4%)、(NH4)2SO4(1%、2%、3%)、CuSO4.5H2O(0.04、0.4、4 mmol/L)、MnSO4(0.001、0.01、0.1 mmol/L)。结果表明:所试浓度的豆渣和(NH4)2SO4、0.01 mmol/L MnSO4均显著提高基质的粗蛋白含量,其中2%的豆渣、3%的(NH4)2SO4效果较好;所试浓度的豆渣、(NH4)2SO4和MnSO4均显著提高漆酶、锰过氧化物酶的活性,0.04、0.4、4 mmol/L CuSO4.5H2O显著提高漆酶的活性,而只有0.4和4 mmol/L的CuSO4.5H2O显著提高锰过氧化物酶的活性,其中2%的豆渣、3%的(NH4)2SO4、0.4 mmol/L的CuSO4.5H2O和0.01 mmol/L的MnSO4对漆酶活性提高的幅度最大,当添加的豆渣、(NH4)2SO4、CuSO4.5H2O和MnSO4的浓度分别为3%、3%、4 mmol/L和0.01 mmol/L时,对应的锰过氧化物酶活性最高。漆酶的活性与发酵基质的粗蛋白含量可能呈正相关关系。     

Effect of manipulating progesterone before timed artificial insemination on reproductive and endocrine outcomes in high-producing multiparous Holstein cows

Our objective was to evaluate the effect of manipulating progesterone (P4) concentrations before timed artificial insemination (TAI) on reproductive and endocrine outcomes in high-producing Holstein cows. Multiparous lactating Holstein cows (n = 80) were synchronized for first TAI using a Double-Ovsynch protocol and were randomly assigned to receive 25 mg of PGF_2α 1 d after the first GnRH treatment of the Breeding-Ovsynch protocol that included a once-used P4 insert (low-P4 group) or to receive 2 new P4 inserts during the Breeding-Ovsynch protocol (high-P4 group). Blood samples were collected thrice weekly from ?10 to 32 d relative to TAI for all cows and from 32 to 67 d after TAI for pregnant cows and were analyzed for P4 and pregnancy-specific protein B (PSPB) concentrations. Expression of IFNτ-stimulated gene 15 (ISG15) was assessed in blood leukocytes 18 and 20 d after TAI. As expected, P4 concentrations were greater for high-P4 cows than for low-P4 cows from 3 to 8 d before TAI. Incidence of double ovulation was 3-fold greater for low-P4 cows than for high-P4 cows (33 vs. 10%), which resulted in more twin pregnancies 32 d after TAI for low-P4 cows than for high-P4 cows (29 vs. 0%). Low-P4 cows had larger preovulatory follicles at the last GnRH treatment of the Double-Ovsynch protocol and greater P4 concentrations than high-P4 cows after TAI. Relative expression of ISG15 mRNA 18 and 20 d after TAI was greater for low-P4 cows than for high-P4 cows and for pregnant cows than for nonpregnant cows. Overall, PSPB concentrations tended to be greater for low-P4 cows than for high-P4 cows, and pregnant cows had greater P4 concentrations than nonpregnant cows. In summary, cows with low P4 before TAI had increased preovulatory follicle diameter, PSPB concentrations, relative expression of ISG15 mRNA 18 and 20 d after TAI, double ovulations, and twinning compared with cows with high P4 before TAI. Increasing P4 before TAI may effectively decrease double ovulation and twinning in high-producing multiparous Holstein cows.     

Estimation of daily intake of phenols in hospital meal samples

Daily intakes of 12 phenols which are possible endocrine disruptors were estimated in hospital meals from 2000 to 2001. 4-Nonylphenol (4-NP (mix)) and bisphenol A (BPA) were detected at levels of 5.0 to 19.4 ng/g and 0.2 to 1.1 ng/g, respectively. 4-tert-Butylphenol, 4-n-pentylphenol, 4 -tert-pentylphenol, 4-n-hexylphenol, 4-n-heptylphenol and 4-tert-octylphenol were detected at levels of 0.1 to 2.4 microg/g. The daily intakes of 4-NP (mix) and BPA were 5.8 microg/day and 0.42 microg/day, respectively. The daily intakes of other phenols were less than 1 microg/day.     

25℃NH3-K2SO4-(NH4)2SO4-H2O体系相平衡的研究

用等温法测定了 2 5℃NH3 K2 SO4 (NH4) 2 SO4 H2 O体系的液固相平衡数据 ,结果表明 ,随着液相中自由氨浓度的增加 ,硫酸钾和硫酸铵的溶解度都在明显降低。依据实验数据绘制的相图 ,提出了氨盐析法从硫酸氢钾水溶液中提取硫酸钾和硫酸铵的生产工艺 ,并对此工艺进行了分析计算。     

营养盐对能源甜菜酒精发酵的影响

利用正交设计法对在能源甜菜酒精发酵过程中起重要作用的5种营养盐进行研究,结果表明：试验因素所起作用顺序为：KH2PO4〉（NH4）2SO4〉CaCl2〉KH2P04×过磷酸钙〉MgSO4〉过磷酸钙,优化后营养盐的添加量分别为（NH4）2SO4：1g／L、MgSO4：10g／L、KH2PO4：10g／L、CaCL2：10g／L、过磷酸钙：10g／L。营养盐KH2PO4与过磷酸钙之间有较强的交互作用,且达显著水平。营养盐添加对不同底物状态产生效果不同,适宜的添加量时甜菜汁比甜菜糊的酒精转化率高。     

甜高粱茎秆汁液酒精发酵及其经济可行性研究

研究了（NH4）SO4，KH2PO4和MgSO4对甜高粱茎秆汁液酒精发酵的影响，并对甜高粱茎秆汁液酒精发酵的经济可行性进行了分析。结果表明，（NH4）2SO4和KH2PO4的添加有利于提高甜高粱汁酒精发酵的产量和产率，MgSO4的添加无益于酒精产量的提高；在（NH4）2SO4和KH2PO4的用量分别为2g／L和5g／L时，终酒精浓度为94．5g／L，酒精产率为0．44。经济性分析表明，甜高粱茎秆汁液酒精发酵生产酒精可以获得很好的经济效益。     

Mutagenicity of aminonitrophenol compounds in Salmonella typhimurium: a study of structural-activity relationships

In our studies of structure-activity relationships, four aminonitrophenol isomers and eleven derivatives of 3-amino-4-nitrophenol and 4-amino-3-nitrophenol were tested for their ability to induce mutations in Salmonella typhimurium strains TA1535, TA100, TA1537, TA1538 and TA98. In the presence of an Aroclor-1254-induced rat-liver microsomal activation system (S9mix), 4-N- β -hydroxyethylamino-3-nitroanisole and (4-amino-3-nitro) phenoxyethanol were mutagenic in several of these strains. The compounds 3-amino-4-nitrophenol, 3-N-methylamino-4-nitrophenol, 3-N-β-hydroxyethylamino-4-nitrophenol, 3-amino-4-nitroanisole, 3-N-methylamino-4-nitroanisole, 3-N- β -hydroxyethylamino-4-nitroanisole, (3-amino-4-nitro)phenoxyethanol, (3-methylamino-4-nitro)phenoxyethanol, (3-N- β -hydroxyethylamino-4-nitro)phenoxyethanol, 4-amino-3-nitrophenol and 4-N- β -hydroxyethylamino-3-nitrophenol were inactive, both in the presence and in the absence of S9 mix. In contrast to the results with 3-amino-4-nitrophenol and 4-amino-3-nitrophenol, which were negative, the isomers 2-amino-4-nitrophenol and 2-amino-5-nitrophenol were found to be mutagenic. These results on mutagenic and non-mutagenic aminonitrophenols and their derivatives suggest that the occurrence of mutagenic activity among these compounds depends on the nature of the substituent chemical groups and their position in the molecular structure of the compounds.
Aminonitriphenols: relation structure-activité     

Implications of Lactobacillus collinoides and Brettanomyces/Dekkera anomala in phenolic off-flavour defects of ciders

Different Lactobacillus collinoides and Brettanomyces/Dekkera anomala cider strains were studied for their ability to produce volatile phenols in synthetic medium. All strains were able to produce 4-ethylcatechol (4-EC), 4-ethylphenol (4-EP) and 4-ethylguaiacol (4-EG) from caffeic, p-coumaric and ferulic acids, respectively. Interestingly, D. anomala and L. collinoides were also able to produce 4-EC, 4-EP and 4-EG in cider conditions. The quantities of ethylphenols produced by these two species were similar in both tested ciders. The impact of precursor quantities was studied and it showed that the addition of caffeic and p-coumaric acids in ciders allowed for higher 4-EC and 4-EP production by D. anomala and L. collinoides. In parallel, D. anomala and L. collinoides strains were isolated from a phenolic off-flavour defective bottled cider after ethylphenol production hence confirming the implication of these two species in this cider spoilage. Finally, detection thresholds of the main ethylphenols were determined in ciders by orthonasal and retronasal sampling. The 4-EC and 4-EP detection thresholds (close to 20-25mg/l and 1.5-2.0mg/l, respectively) were matrix dependant.     

硫酸钙溶解行为初探

工业氯化钾的除钙是一个至今尚未解决的技术难题,其核心是硫酸钙的增溶.为此,文章探讨了硫酸钙在盐酸及碳酸氢铵-盐酸体系的溶解行为.结果表明:在0～2.5 mol/L范围内增加盐酸浓度可在一定程度增溶硫酸钙,但最大酸溶率低于15%;采用碳酸氢铵-盐酸物相转化再酸溶的方法则可使88%的硫酸钙转化成碳酸钙,总溶钙率达到91%,硫酸钙的物相转化(硫酸钙→碳酸钙)是增溶主要途径.     

毛纱上浆用丁二酸酐酰化明胶浆料的制备及其性能

针对明胶在室温凝胶且在毛纱上浆时存在浆膜韧性差的问题,采用丁二酸酐(C₄H₄O₃)对明胶进行酰化改性,合成了一种毛纱室温上浆用改性明胶蛋白(Gel-C₄H₄O₃)浆料。借助红外光谱仪、X射线衍射仪、扫描电子显微镜及差示扫描量热仪对Gel-C₄H₄O₃浆料结构及玻璃化转变温度进行测试表征,系统研究了酰化度与Gel-C₄H₄O₃浆液和浆膜性能的关系。结果表明:C₄H₄O₃可与明胶分子链上的氨基发生酰化反应;与采用丙烯酸、丙烯酰胺、丙烯酸酯类单体接枝改性明胶浆料相比,C₄H₄O₃酰化改性后的明胶浆料在室温时不凝胶;当酰化度为0.96时,Gel-C₄H₄O₃浆液对毛纱表现出优良的黏附性,Gel-C₄H₄O₃浆膜的断裂强度和韧性显著增加。此研究为毛纱室温上浆提供了性能优良的浆料制备方法。     

贮藏温度对鲜枸杞生理指标和营养品质的影响

为研究鲜枸杞在不同贮藏温度下的品质损耗规律,将新鲜采收的枸杞果实分别放在4℃和-4℃冷库贮藏21 d,测定并分析生理指标和营养品质的变化。结果表明:-4℃贮藏显著下调鲜枸杞的呼吸速率(呼吸峰值比4℃下调37%)和乙烯产生速率,延缓鲜枸杞硬度下降,并提高商品果率,贮藏末期硬度和商品果率分别比4℃提高21.54%和10.95%;同时,-4℃贮藏的鲜枸杞可溶性固形物、可滴定酸、游离氨基酸和类胡萝卜素含量显著高于4℃,说明鲜枸杞在-4℃贮藏21 d仍保持较好的营养品质。     

Solid solutions between CrO4- and SO4-ettringite Ca6(Al(OH)6)2[(CrO4)x(SO4)(1-x)]3*26 H2O

Chromate is a toxic contaminant of potential concern, as it is quite soluble in the alkaline pH range and could be released to the environment. In cementitous systems, CrO4(2?) is thought to be incorporated as a solid solution with SO4(2?) in ettringite. The formation of a solid solution (SS) could lower the soluble CrO4(2?) concentrations. Ettringite containing SO4(2?) or CrO4(2?) and mixtures thereof have been synthesized. The resulting solids and their solubility after an equilibration time of 3 months have been characterized. For CrO4-ettringite at 25 °C, a solubility product log K(S0) of ?40.2 ± 0.4 was calculated: log K(CrO4?ettringite) = 6log{Ca2+} + 2log{Al(OH)4(?)} + 3log{CrO4(2?)} + 4log{OH?} + 26log{H2O}. X-ray diffraction and the analysis of the solution indicated the formation of a regular solid solution between SO4- and CrO4-ettringite with a miscibility gap between 0.4 ≤ XCrO4 ≤ 0.6. The miscibility gap of the SO4- and CrO4-ettringite solid solution could be reproduced with a dimensionless Guggenheim fitting parameter (a0) of 2.03. The presence of a solid solution between SO4- and CrO4-ettringite results in a stabilization of the solids compared to the pure ettringites and thus in an increased uptake of CrO4(2?) in cementitious systems.     

Relationship between pregnancy per artificial insemination and early luteal concentrations of progesterone and establishment of repeatability estimates for these traits in Holstein-Friesian heifers

Pregnancy per insemination is a major determinant of reproductive efficiency in cattle and is affected by concentrations of progesterone (P4) during early pregnancy. The relationship between pregnancy per artificial insemination (P/AI) and early luteal concentrations of P4, and repeatability of concentrations of P4 was examined on d 4, 5, 6, and 7 (day of standing estrus=d 0) in 118 Holstein Friesian heifers following 2 rounds of AI to 1 high-fertility sire. Repeatability estimates (R(e)) for P/AI were established following 4 rounds of AI. We found a linear and quadratic relationship between P/AI and concentrations of P4 on d 4 to 7 after estrus, as well as a linear and quadratic relationship between P/AI and the change in concentration of P4 from d 4 to 7 and from d 5 to 7. Optimum concentrations of P4 to maximize probability of P/AI were 2.5, 4.0, 5.0, 5.2, and 3.5 ng/mL for d 4, 5, 6, and 7, and the change from d 4 to 7, respectively. Repeatability of P/AI following 4 rounds of AI was low (R(e)=0.07). Repeatability estimates for concentrations of P4 from cycle to cycle indicated low repeatability between d 4 (R(e)=0.05) and 7 (R(e)=0.20). These data indicated the importance of P4 in the early luteal phase for pregnancy survival, but also demonstrated that high concentrations of P4 on these days have a deleterious effect on embryo viability. Early luteal (d 4 to 5) concentrations of P4 were a reasonable predictor of concentrations on d 7 and could be used as a diagnostic tool to identify animals at risk of subsequent embryo loss.     

Isomer-specific degradation of branched and linear 4-nonylphenol isomers in an oxic soil

Using (14)C- and (13)C-ring-labeling, degradation of five p-nonylphenol (4-NP) isomers including four branched (4-NP(38), 4-NP(65), 4-NP(111), and 4-NP(112)) and one linear (4-NP(1)) isomers in a rice paddy soil was studied under oxic conditions. Degradation followed an availability-adjusted first-order kinetics with the decreasing order of half-life 4-NP(111) (10.3 days) > 4-NP(112) (8.4 days) > 4-NP(65) (5.8 days) > 4-NP(38) (2.1 days) > 4-NP(1) (1.4 days), which is in agreement with the order of their reported estrogenicities. One metabolite of 4-NP(111) with less polarity than the parent compound occurred rapidly and remained stable in the soil. At the end of incubation (58 days), bound residues of 4-NP(111) amounted to 54% of the initially applied radioactivity and resided almost exclusively in the humin fraction of soil organic matter, in which chemically humin-bound residues increased over incubation. Our results indicate an increase of specific estrogenicity of the remaining 4-NPs in soil as a result of the isomer-specific degradation and therefore underline the importance of understanding the individual fate (including degradation, metabolism, and bound-residue formation) of isomers for risk assessment of 4-NPs in soil. 4-NP(1) should not be used as a representative of 4-NPs for studies on their environmental behavior.     

Kinetics and mechanism of photoactivated periodate reaction with 4-chlorophenol in acidic solution

The application of photoactivated periodate (UV/IO4-) to the degradation of 4-chlorophenol (4-CP) was explored in this study. Under low irradiation intensities (23 microW/cm2), wavelength of 266 nm, and pH 3, 4-CP was observed to degrade by pseudo-first-order reaction kinetics. The small reduction in 4-CP degradation in the presence of tert-butyl alcohol (t-BuOH) suggests that degradation of 4-CP by UV/IO4- was not dominated by an OH* pathway. O3 production was suppressed in the presence of t-BuOH under O2-limited environments and in the presence of 4-CP. Faster degradation of 4-CP in the presence of an OH* scavenger under nitrogen purging as compared to air-saturated conditions indicates that O(3P) is an important reactive species with 4-CP in this system. When 4-CP is added to the system, IO3- production is enhanced. On the basis of the elimination of potential reaction pathways, O(3P) and IO3* are suspected reactive species with 4-CP in this system.     

Purification and characterization of alkylcatechol 2,3-dioxygenase from butylphenol degradation pathway of Pseudomonas putida MT4

Alkylcatechol 2,3-dioxygenase was purified from the cell extract of recombinant Escherichia coli JM109 harboring the alkylcatechol 2,3-dioxygenase gene (bupB) cloned from the butylphenol-degrading bacterium Pseudomonas putida MT4. The purified enzyme (BupB) showed relative meta-cleavage activities for the following catechols: catechol (100%), 4-methylcatechol (572%), 4-n-butylcatechol (185%), 4-n-hexylcatechol (53%), 4-n-heptylcatechol (45%), 4-n-nonylcatechol (10%), 4-tert-butylcatechol (0%), and 3-methylcatechol (33%). The kinetic parameters, namely, K(m) and V(max), for catechol, 4-methylcatechol, and 4-n-butylcatechol, were 23.4, 8.4, and 6.5 microM and 25.8, 76.9, and 18.0 U mg(-1), respectively. These results suggest that BupB has broad substrate specificity for 4-n-alkylcatechols.     

Influence of structure on colour stability of anthocyanins and flavylium salts with ascorbic acid

Ascorbic acid (330 mg/l) was added to buffered solutions (pH 2.35) of malvidin 3-glucoside, malvidin 3,5-diglucoside and flavylium salts with differing 4-substituents, viz.: 5,7-dihydroxy-4′-methoxyflavylium chloride, 5,7-dihydroxy-4-methyl-4′-methoxyflavylium chloride and 5,7-dihydroxy-4-phenyl-4′-methoxyflavylium chloride. Malvidin 3,5-diglucoside lost colour slower than malvidin 3-glucoside and flavylium colour stability was in the order 4-phenyl>4-methyl>4-H. The results demonstrate that anthocyanin reactivity and the status of the flavylium 4-substituent play an important role in colour stability under these conditions.