饲料中添加花粉和酵母硒对中华鳖幼鳖生长和非特异性免疫功能的影响

在基础饲料中分别添加0.5×10-6酵母硒、0.1%花粉、0.5×10-6酵母硒+0.1%花粉的混合物,投喂中华鳖幼鳖90d后。测定幼鳖的生长和血清中谷胱甘肽过氧化物酶(GSH PX)、超氧化物歧化酶(SOD)活性、T淋巴细胞转化率、自然杀伤细胞(NK)活性。同对照组相比,0.5×10-6酵母硒+0.1%花粉组能显著促进中华鳖的生长(P<0.05),0.5×10-6酵母硒组与0.1%花粉组的日增重率均高于对照组,但差异不显著(P>0.05)。各组间成活率无差异(P>0.05)。0.5×10-6酵母硒组NK细胞活性以及血清中SOD酶和GSH PX酶的活力分别比对照组高了156.06%、44.7%、47.5%(P<0.05)。0.1%花粉组、0.5×10-6酵母硒+0.1%花粉组血清中GSH PX酶的活力分别比对照组高了39.9%、32.9%(P<0.05),但两组的SOD酶活力与对照组相比均无显著性差异(P>0.05)。0.5×10-6酵母硒组以及0.1%花粉组的T淋巴细胞转化率均比对照组高,但差异均不显著(P>0.05)。0.1%花粉组的NK细胞活性也比对照组高,但差异不显著(P>0.05)。0.5×10-6酵母硒+0.1%花粉组能显著增强中华鳖T淋巴细胞转化率及NK细胞活性(P<0.05)。     

Infection with foot-and-mouth disease virus (FMDV) induces a natural killer (NK) cell response in cattle that is lacking following vaccination

Natural killer (NK) cells play a role in innate antiviral immunity by directly lysing virus-infected cells and producing antiviral cytokines such as interferon gamma (IFN-γ). We developed a system for characterizing the bovine NK response to foot-and-mouth disease virus (FMDV), which causes a disease of cloven-hoofed animals and remains a threat to livestock industries throughout the world. IL-2 stimulation of PBMC resulted in poor killing of human K562 cells, which are often used as NK target cells, while lysis of the bovine BL3.1 cell line was readily detected. Depletion of NKp46-expressing cells revealed that 80% of the killing induced by IL-2 could be attributed to NKp46⁺ cells. In order to characterize the response of NK cells against FMDV in vivo, we infected groups of cattle with three different strains of the virus (A24 Cruzeiro, O1 Manisa, O Hong Kong) and evaluated the cytolytic ability of NK cells through the course of infection. We consistently observed a transient increase in cytolysis, although there was variation in magnitude and kinetics. This increase in cytolysis remained when CD3⁺ cells were removed from the preparation of lymphocytes, indicating that cytolysis was independent of MHC-T cell receptor interaction or γδ T cell activation. In contrast, animals monitored following vaccination against FMDV did not exhibit any increase in NK killing. These data suggest that NK cells play a role in the host immune response of cattle against FMDV, and contrast with the suppression of NK activity previously observed in swine infected with FMDV.     

氮钾互作对马铃薯产量,品质与氮磷钾吸收的影响

本文研究了四个氮钾处理对马铃薯“金冠”品种植株生长、块茎产量与品质和氮磷钾吸收的影响.结果表明:在钾水平相同时,高氮比低氮抑制植株生长与降低块茎产量,尤其是在高钾条件下增氮的减产效应更明显.低氮时增钾明显地促进植株生长与提高块茎产量,而高氮时增钾则抑制植株生长与降低块茎产量.处理中,以低氮高钾(N_4K_6)处理的块茎产量、品质与商品率最佳.氮钾互作明显地影响植株对氮、钾吸收,而对磷吸收影响不大.植株的氮、磷含量与块茎产量无显著相关,植株的钾含量与块茎产量呈显著正相关.植株体内N/K比值与块茎产量呈显著负相关。     

Estimation of associative nitrogen fixation in relation to water regime and plant nutrition in a long-term pot experiment with rice (Oryza sativa L.)

Summary The contribution of associative N₂ fixation to the N nutrition of lowland rice was estimated in a long-term pot experiment with ten consecutive crops of rice. The experiment comprised two N and two K levels with wet (WF) and dry fallow (DF) between the cropping seasons. Growth of N₂-fixing cyanobacteria was prevented. Greatest yields were obtained in the high NK fertilizer treatment, but with continuation of the experiment yields responsed more to DF than to WF. Nitrogenase activity, however, was favoured by WF. Higher K application increased and higher N application decreased nitrogenase activity. Under WF treatments the organic C and total N contents of the soil remained unchanged during the experimental period, but alternate drying and flooding in DF treatments caused a decline. Lower N fertilizer rates in the second five-crop period did not affect yields, but increased the ratio of N removed to N applied. For the ten-crop period the estimated N balance was positive in the low-N and negative in the high-N treatments. N balances were also established separately for both the first and the second halves of the ten-crop period. In the first period N losses were higher, and the N balance was mostly negative. In the second period only high-N combined with low-K fertilization resulted in a negative N balance. DF favoured N losses in the first but not in the second period. The highest N gain in the second period was found in the DF treatment with low-N and high-K application. In this treatment, nearly one-quarter of the N taken up by the above-ground parts of the plants could be ascribed to associative N₂ fixation. In the corresponding treatment with the higher N level and a 49% higher yield, the contribution of fixed N declined to less than 5%. When harvested straw contained more than 10 mg N g^–1, the N balance was mostly negative, while at N contents less than 10 mg N g^–1, the N balance was generally positive.     

Bovine NK cells acquire cytotoxic activity and produce IFN-gamma after stimulation by Mycobacterium bovis BCG- or Babesia bovis-exposed splenic dendritic cells

Early interactions of innate immune cell populations, such as dendritic cells (DC) and natural killer (NK) cells, can affect the ability of the acquired immune response to control infection of intracellular microorganisms. In this study, we investigated the activation of bovine NK cells by CD13(+) splenic DC stimulated with either Mycobacterium bovis BCG or Babesia bovis merozoites. Splenic DC were used either immediately after selection (cytokine(-)) or after exposure to GM-CSF, IL-4 and Flt3L for 72 h (cytokine(+)). Phenotypic analyses showed up-regulation of MHCII, CD80 and CD86 on cytokine(+) DC when compared to cytokine(-) DC. Purified NK cells (CD335(+)CD3(-)CD2(+/-)CD8alpha(+/-)) were co-cultured with microbial-exposed cytokine(-) DC or cytokine(+) DC in either transwell or cell-to-cell format and NK cell IFN-gamma production and cytotoxicity were assessed. NK cell IFN-gamma production was dependent on cell-to-cell contact. Microbial-stimulated cytokine(+) DC induced significantly more IFN-gamma production from NK cells than cytokine(-) cells. In contrast, cytotoxicity and perforin up-regulation were more pronounced in NK cells cultured with cytokine(-) DC than cytokine(+) DC. Therefore, activation of bovine NK cells by microbial-stimulated CD13(+) splenic DC is influenced by the maturation state of the DC suggesting different roles for the splenic DC during disease-induced maturation.     

低能量氦氖激光照射对荷瘤小鼠NK细胞活性的影响

研究低能量氦氖激光照射荷瘤小鼠对ＮＫ细胞活性的影响。选取ＢＡＬＢ／Ｃ雄性小鼠腹腔接种Ｓ１８０,接种后进行激光照射小鼠内眼角,监测了正确对照组,肿瘤对照组和７．３３、１１．００、１４．６７、２２．００、２９．３３Ｊ／ｃｍ＾２五个激光照射线能明显提高荷瘤小鼠ＮＫ细胞活性;７．３３、２９．３３Ｊ／ｃｍ＾２照射组则长高不明显。     

蝉花宝牌蝉花片免疫功能评价

将蝉花宝牌蝉花片(商品名)设低、中、高3个剂量组,分别相当人体推荐量的5、10、30倍,同时设阴性对照组(1%羧甲基纤维素钠),连续1个月经口给予小鼠不同剂量的样品,进行迟发型超敏反应(DTH)、腹腔巨噬细胞吞噬鸡红细胞、抗体生成细胞检测、自然杀伤(NK)细胞杀伤活性和脾淋巴细胞转化等实验,以评估其免疫功能。结果表明,与阴性对照组比较,受试3个剂量组足跖肿胀度极显著增加(P0.01);中、高剂量组溶血空斑数和血清溶血素抗体积数值均极显著增加(P0.01),腹腔巨噬细胞吞噬鸡红细胞的吞噬率、吞噬指数显著增加(P0.05,P0.01);高剂量组NK细胞活性显著升高(P0.05)。蝉花宝牌蝉花片(商品名)具有显著的免疫调节功能。     

中草药复方制剂对猪口蹄疫免疫过程中NK细胞的影响

将70头30日龄仔猪随机分成7组,每组10头,在口蹄疫免疫过程中按1%添加剂量使用中草药复方制剂,Ⅰ、Ⅱ、Ⅲ组分别在免疫前5天、3天、当天开始连续饲喂3天,Ⅳ、Ⅴ、Ⅵ组分别在免疫前5天、3天、当天饲喂1天。对照组（Ⅶ组）不喂药。分别于免疫前一天和免疫后14d、21d、28d和二免后28d,采血检测NK细胞数量。结果表明：投药组NK细胞数量均高于对照组,Ⅰ、Ⅱ、Ⅲ组NK细胞数量高于Ⅳ、Ⅴ、Ⅵ组,Ⅱ组NK细胞数量最高,其中Ⅰ、Ⅱ、Ⅲ组与对照组差异显著（P<0.05）,Ⅳ、Ⅴ、Ⅵ组与对照组差异不显著（P>0.05）。     

Growth and Nutritional Response of Melon to Water Quality and Nitrogen Potassium Fertigation Levels under Greenhouse Mediterranean Conditions

The Mediterranean area has been experiencing an extensive development of intensive horticulture, with a majority of that located in arid and semi-arid regions with limited water resources and poor water quality. One of the most important greenhouse vegetable crops is melon. This article studies the effects of different nitrogen–potassium (N–K) fertilizers applications and two types of irrigation water on yield and nutritional behavior of melon crop Cucumis melo L. (var. cantalupensis Naud. Alpes). The trial was conducted during two cycles under Mediterranean greenhouse conditions, on sandy mulching soil. The experimental design was bifactorial: NK fertigation and water quality, with three nutrition levels and two water qualities [MS with electrical conductivity (EC) = 0.6 dS m^?1 and HS with EC = 2.3 dS m^?1]. During the first cycle, the fertigation levels were F₁ (50% NK), F₂ (100% NK), and F₃ (125% NK). In the second cycle, the fertigation levels were F₂, F₄ (125% N and 150% K) and F₅ (180% N and 220% K). Treatment F₂ was the recommended total doses (220 kg N ha^?1 and 355 kg K ha^?1). The increase in the NK concentration of the nutritive solution produced a rise in commercial production. The salinity of irrigation water did not affect marketable yield but had an effect on the fruit size, which was compensated for by an increase in the amount of fruit produced. Dry-matter production, N, and K uptake by plant (g m^?2) were evaluated in the first and second trials. Salinity and NK nutrition levels significantly affected (P < 0.05) dry matter and N and K uptake by melon plant. Nitrogen and K uptake present interesting correlations with production and with each other, as established by mean regression analysis.     

山羊、水牛感染肝片吸虫后淋巴细胞自然杀伤活性动态变化

自然杀伤 (NK)活性是在细胞水平反映机体天然免疫力的重要指标之一。本实验以SP2 / 0细胞为靶细胞 (即效应细胞 ) ,采用乳酸脱氢酶(LDH)短程释放法测定人工感染肝片吸虫的水牛和山羊的外周血液中淋巴细胞的NK活性动态变化。从测定结果的相对值来看 ,发现山羊在感染肝片吸虫后NK活性有 2次高峰 ,推测与虫体的发育或感染山羊的免疫状态有关 ;2个感染组 (Ⅰ ,2 0 0个囊蚴 /只 ;Ⅱ ,50 0个囊蚴 /只 )的变化趋势表明 ,感染量与NK活性无相关关系。感染水牛的NK值仅略高于对照组 ,无明显的高峰。而绝对值结果又反映出不同动物的NK活性有差异 ,水牛的NK活性比山羊高 ,说明水牛对肝片吸虫的天然免疫力比山羊强