Mixed leukocyte reactions and histocompatibility in rats

Mixed leukocyte culture tests have been carried out on two hetero geneous but genetically defined backcross populations of rats to determine whether the reactions observed can provide the basis for histocompatibility matching. The experiments were designed so that only-one-way reactions could occur. Only when the donors of individual leukocyte mixtures differed at the important Ag-B histocompatibility locus was there any in vitro reactivity, and differences at this locus were invariably associated with the prompt rejection of skin homografts. Determination of compatibility at this locus proved to be important in that it facilitated the prolongation of survival of skin homografts by immunosuppressive therapy.     

Exploiting tolerance processes in transplantation

The full potential of organ transplantation has not yet been realized because of the hazards associated with the long-term use of immunosuppressive drugs. Modern research into mechanisms of immune tolerance offers the promise of reprogramming the immune system, so as to harness the body's natural tolerance mechanisms in the service of graft acceptance. This would allow the minimization of immunosuppressive treatment and offers the prospect of eventually weaning transplant recipients off their drugs.     

Mixed lymphocyte reaction: an in vitro test for antilymphocytic serum activity

When Lewis rats were exposed to antilymphocytic serum, produced in rabbits, to Lewis lymphoid cells, the transformation of their thoracic duct lymphocytes in response to foreign lymphoid cells was markedly reduced in comparison with that in response to similar cells from donors treated with saline or normal rabbit serum. It is suggested that the mixed lymphocyte reaction may be used as an in vitro test for the in vivo activity of antilymphocytic serum.     

杨树湿地松组织培养愈伤组织耐盐性

对杨树无性系ＮＬ－８０１０５，ＮＬ－８０１０６，ＮＬ－８０１１７和湿地松组织培养愈伤组织的耐盐性进行了研究。结果表明：以ＭＳ为基本培养基，添加２，４－Ｄ２．０ｍｇ·ｋｇ－１和ＫＴ０．５ｍｇ·ｋｇ－１，诱导这些树种愈伤组织效果好；在含氯化钠的培养基上，杨树不同器官外植体的愈伤组织诱导能力和耐盐程度有差异，外植体茎、叶比根强；杨树继代愈伤组织的耐盐能力显著高于湿地松，这与植株水平的耐盐性相一致，表明用愈伤组织鉴别这些植物耐盐性的方法是可行的     

鸢尾组织培养过程中根系的诱导与移栽试验

以路易斯鸢尾的无根组培苗为材料,采用萘乙酸(NAA)、吲哚丁酸(IBA)、吲哚乙酸(IAA)和6-苄氨基嘌呤(6-BA)进行3水平4因素的正交设计,对鸢尾组织培养过程中根的诱导进行不同生长调节剂配比的试验。结果表明,在9个处理中,较高浓度的IBA(1 mg·L^-1)、NAA(1 mg·L^-1)和较低浓度的IAA(0.5 mg·L^-1)、6-BA(0.2 mg·L^-1)能促进路易斯鸢尾根的诱导和生长,其中在MS+IBA 1.0 mg·L^-1+NAA 1.0 mg·L^-1+IAA 0.5 mg·L^-1+6-BA 0.2 mg·L^-1培养基中,平均生根率达到83.3%,高于其余处理,而且生长良好。以生根组培苗作为材料,在不同环境中进行炼苗试验,表明在人工气候箱和室内炼苗无明显差异。以平均高度在14～15 cm,粗细均匀,根数在4～5条的生根苗在培养基质下进行移栽试验,表明在泥炭∶珍珠岩∶蛭石3∶3∶4加适量缓释复合肥培养基质下,移栽成活率最高,达到93.3%,高于其它处理。     

Cryopreservation, culture, and transplantation of human fetal mesencephalic tissue into monkeys

Studies in animals suggest that fetal neural grafts might restore lost neurological function in Parkinson's disease. In monkeys, such grafts survive for many months and reverse signs of parkinsonism, without attendant graft rejection. The successful and reliable application of a similar transplantation procedure to human patients, however, will require neural tissue obtained from human fetal cadavers, with demonstrated cellular identity, viability, and biological safety. In this report, human fetal neural tissue was successfully grafted into the brains of monkeys. Neural tissue was collected from human fetal cadavers after 9 to 12 weeks of gestation and cryopreserved in liquid nitrogen. Viability after up to 2 months of storage was demonstrated by cell culture and by transplantation into monkeys. Cryopreservation and storage of human fetal neural tissue would allow formation of a tissue bank. The stored cells could then be specifically tested to assure their cellular identity, viability, and bacteriological and virological safety before clinical use. The capacity to collect and maintain viable human fetal neural tissue would also facilitate research efforts to understand the development and function of the human brain and provide opportunities to study neurological diseases.     

南方型紫花苜蓿基因型在组织培养条件下对NaCl的耐性

以4个南方型紫花苜蓿基因型为材料,通过测定愈伤组织生长状况、组织培养条件下的发芽率、苗高和幼根长指标,研究南方型紫花苜蓿对NaCl的耐受性。结果表明: NaCl对4个南方型紫花苜蓿的生长指标的影响均存在较大差异,其中愈伤组织生长和发芽率受NaCl影响小,幼根生长对NaCl的耐受性较大,120 mmol·L -1NaCl严重影响了南方型紫花苜蓿幼苗生长。当培养基中加入NaCl时,‘Millennium’和‘Vitoria’的耐受性较强,而‘Powerplant’的耐受性较差,在进行南方型紫花苜蓿遗传转化的筛选时,应注意不同基因型和受体类型对NaCl的耐受性。     

盐胁迫对3个越橘品种组培苗生长的影响与耐盐性评价

【目的】研究不同品种越橘组培苗在盐胁迫下生长和Na~+、K~+含量的变化特点及耐盐性差异,为筛选耐盐越橘种质资源提供依据。【方法】以我国长江流域产区及西南产区主栽的3个南高丛越橘品种‘奥尼尔’、‘雷戈西’、‘密斯梯’组培苗为试材,研究不同浓度(0(CK),15,30,45,60,75,90,105,120 mmol/L)NaCl处理对3个越橘品种组培苗鲜质量、存活率、芽增殖率、新生芽长以及K~+、Na~+含量及其比值的影响,并利用主成分分析法和隶属函数法对3个越橘品种的主要耐盐指标和综合耐盐性进行评价。【结果】随着NaCl浓度的提高,3个越橘品种组培苗的鲜质量、存活率、芽增殖率和新生芽长均呈下降趋势,在NaCl浓度为120 mmol/L时,‘奥尼尔’上述指标分别较CK下降54.7%,20.0%,83.3%和84.1%,‘雷戈西’分别下降51.0%,33.0%,75.1%和86.7%,‘密斯梯’分别下降35.4%,40.0%,96.1%和100.0%。3个越橘品种组培苗Na~+含量随NaCl浓度升高而逐渐增加,而K~+含量和K~+/Na~+比均下降,在NaCl浓度为120 mmol/L时,‘奥尼尔’、‘雷戈西’、‘密斯梯’Na~+含量分别较CK上升4.1,3.6和4.1倍,而K~+含量和K~+/Na~+比分别较CK下降20%和80%,19%和77%,27%和83%。3个越橘品种的耐盐性综合指数分别为0.46,0.66和0.24。【结论】NaCl胁迫对越橘组培苗的生长和增殖有抑制作用,能显著降低越橘植株中K~+/Na~+比值;3个越橘品种组培苗的耐盐性从强到弱依次为‘雷戈西’、‘奥尼尔’、‘密斯梯’。     

杜仲杉木人工混交林不同混交比例研究

该研究以纯杜仲林为对照,对杜仲杉木混交林的种植配比进行了试验分析。结果表明:杜仲和杉木混交造林是一种较好的营林模式。纯杜仲(CD),杜仲杉木1:1(D1S1)和杜仲杉木7:3(D7S3)3种种植配比中,D7S3中的平均树高、胸径、地径和冠幅均大于CD和D1S1处理,表明较高的杜仲种植比例有利于杜仲的生长,不同坡位也表现出相似的规律性特征。与杜仲相同,3种处理中D7S3中杉木生长状态优于CD和D1S1处理。     

竹阔混交林混交类型的综合评价

根据生态系统工程的理论和方法 ,应用系统最优综合评价模型 ,对竹阔混交林 5种类型 2 2个指标进行综合评价。阔叶树的比例为 2 5 %～ 35 %的竹阔混交林综合效益最高 ,为最优方案     

不同中药多糖体外对鸡外周血和脾脏淋巴细胞增殖能力的比较

为比较玉竹多糖、桑叶多糖、杜仲多糖、商陆多糖、淫羊藿多糖体外增强免疫活性,采用酶学检测法测定各中药多糖对鸡胚成纤维细胞的安全浓度,根据安全浓度测定结果,选择250.000μg/ml、125.000μg/ml、62.500μg/ml、31.250μg/ml、15.625μg/ml 5个浓度,用MTT法比较5种中药多糖单独和PHA协同刺激对外周血T淋巴细胞增殖指数的影响,以及比较5种中药多糖单独和LPS协同刺激对脾脏B淋巴细胞增殖率的影响。结果显示,玉竹多糖、桑叶多糖、杜仲多糖、商陆多糖、淫羊藿多糖对鸡胚成纤维细胞的安全浓度分别为1 250.0μg/ml、625.0μg/ml、625.0μg/ml、625.0μg/ml、312.5μg/ml。玉竹多糖、桑叶多糖、杜仲多糖和淫羊藿多糖无论是单独还是协同PHA刺激外周血T淋巴细胞,均不同程度地表现出增强T淋巴细胞的活性。桑叶多糖、杜仲多糖和淫羊藿多糖无论是单独还是协同LPS刺激脾脏B淋巴细胞,均不同程度地显示出良好的增强B淋巴细胞的活性。桑叶多糖和杜仲多糖体外增强免疫效果最佳,在62.500μg/ml和125.000μg/ml时,均显示出较强的增强外周血T淋巴细胞和脾脏B淋巴细胞增殖的能力。     

大豆对硒的富集及耐受能力

研究了大豆对环境硒的生物富集能力,结果表明:大豆对环境硒的生物富集能力与其生育期和环境硒浓度相关;大豆对硒的耐受能力取决于自身的生长发育成熟程度和环境中可利用硒的游离浓度。     

Thermal preference and tolerance of alvinellids

The highest oceanic temperatures are found at hydrothermal vents, where the polychaete Paralvinella sulfincola lives on vent sulfides within steep and dynamic thermal gradients. To determine P. sulfincola thermotolerance and preference, we developed a high-pressure aquarium that mimics in situ thermal gradients and permits P. sulfincola to move within the gradient. These polychaetes were thermotaxic, preferring temperatures of 40 degrees to 50 degrees C. Some individuals remained at 50 degrees C for 7 hours (the duration of the experiment), whereas others endured exposure to 55 degrees C for over 15 minutes, demonstrating that alvinellids prefer high temperatures and are among the most thermotolerant of marine organisms.     

State- and bond-selected unimolecular reactions

Unimolecular reactions are crucial chemical events that have been the focus of increasingly sophisticated investigation in the past decade. Unraveling their details is one fundamental goal of experimental and theoretical studies of chemical dynamics. New techniques are revealing the possibilities, and challenges, of eigenstate- and bondspecific unimolecular reactions. These experiments clearly demonstrate the intimate connection between intramolecular processes and unimolecular reaction dynamics and suggest means of exploiting molecular properties to study and control reactions at the level of individual quantum states.     

Exciplexes and electron transfer reactions

Electronically excited molecules, being better electron donors and acceptors than their ground states, form charge-transfer complexes (exciplexes) which can lead to radical ions. Exciplex emission is widely used to probe polymers and organized media such as membranes and micelles. Exciplexes are also intermediates in photoreactions that lead to unique products. Photochemical electron-transfer processes, which are the basis of silver halide photography and electrophotography, are involved in many reactions of wide scope. Recent studies have led to the discovery of several electron-transfer photooxygenations with a diversity that will probably rival that of singlet oxygen. Both exciplex emission and photochemical electron transfer play important roles in organic photochemistry.