The nature of the toxic properties of the blood plasma of gamma irradiated rats

In addition to the growth of low molecular weight quinoid radiotoxins the toxic effects of albumin were registered in rat plasma 4-24 h following gamma-irradiation. It is assumed that adducts of albumin with quinoid radiotoxins are formed and contribute to the development of radiation injury to critical organism tissues.     

Modifying effect of water-soluble analogs of quinoid radiotoxins on hematopoiesis in gamma-irradiated mice

It was established that quinoid products of tyrosine oxidation, analogues of natural radiotoxins, when used in the studied doses decreased the radiosensitivity of spleen stem cells and enhanced the restoration of bone marrow cellularity of mice exposed to sublethal gamma-radiation doses.     

Synergism in the effect of gamma-radiation and quinoid radiotoxins on mice and cultured lymphoid cells

A considerable increase in the lethal effect of gamma-radiation on mice was noted after postirradiation administration of nontoxic quantities of quinoid radiotoxins (synergism). The same synergistic effect was observed on human lymphoid cells Raji in culture.     

Abscopal action of gamma radiation in the death of lymphoid cells

In the in vitro experiments with lymphoid cells Raji and X63-Ag8.653 gamma-irradiated in a synthetic medium, it was shown that a cessation of division (reproductive death) and lysis (interphase death) of cells were evoked by the abscopal effect of long-lived quinoid radiotoxins enhancing the direct effect of radiation to make it not additive but synergistic: a synergism coefficient was 1.3.     

The problem of peroxidation in radiobiology

A hypothesis is validated concerning the products of free radical oxidation of lipids and the phenol compounds as a mediator unit of the stress-syndrome. The data are reviewed on activation of peroxidation under the effect of radiation, cytochemical agents, etc., secondarily stimulating the neurohumoral system function of homeostasis regulation. With the emotional-algesic and cold-stresses, the regulatory system stimulation is of primary, reflex, nature, but it secondarily promotes the peroxidation activation. The radiotoxins (of the quinoid and lipid nature) appearing in tissues under the effect of ionizing radiation, are similar in structure and mechanism of action to peroxidation activation products formed under the effect of other stress-agents.     

Effect ofγ-irradiated carbohydrates on isolated synaptic membranes

The effect of-irradiated solutions of carbohydrates, mainly glucose, upon Na⁺, K⁺-ATPase and lipid peroxidation in rat brain synaptosomal membranes was studied. The membrane damage by irradiated glucose was enhanced in the presence of Fe²⁺ and was diminished when a free-radical scavenger (BHT) or metal chelators (EDTA, EGTA) were present. It is suggested that a key element in the free-radical membrane damage by irradiated carbohydrates is an Fe²⁺-complex of some species of the radiolysis products. Participation of radiotoxins of carbohydrate origin in radiobiological effects is discussed.     

Ex vivo EPR investigation of metabolic changes in mice treated with radiotoxins

The effect of radiotoxins (RT), obtained from gamma-irradiated potato tubers, on mice have been investigated using ex vivo EPR. Parts of liver, lung, spleen, heart and kidney were used for investigation. The amount of the preparations injected was 0.2 ml, RT concentration varying from 0.1 to 1 LD100 (LD100 = 100 mg/kg). An intraperitoneal injection of RT in dose of 0.1 LD100 resulted in metabolic changes only in spleen. During 8 hours after injection a gradual depression of enzyme ribonucleotide reductase activity in spleen has been observed. After the treatment of mice with a lethal dose of RT signals from nitrosyl complexes have been appeared in spectra from all tissue investigated. The intensities of lines depend both on a time passed after treatment and a sensitivity of tissue to RT action. One of the main reasons of the lethal outcome of mice treated with RT may be the breaking of the compensatory adaptive response due to enhanced hypoxic state resulting from the high concentration of nitrosyl complexes generated in the tissue.     

新疆南北疆灌木植物组成及区系比较

在文献和标本查阅以及野外调查的基础上,比较了北疆和南疆灌木植物的种类、组成及分布区类型的差异,并分析了北疆和南疆灌木植物的相似性。结果表明:新疆共分布有野生灌木植物39科127属462种,其中北疆分布有37科104属350种,南疆分布有28科63属160种。北疆和南疆灌木植物中含2~10种的科最多,分别占北疆和南疆灌木植物总科数的59.5%和60.7%,共有的优势科为菊科(Compositae)、豆科(Leguminosae)和藜科(Chenopodiaceae);在属级水平上均以含1种的属和含2~10种的属占优势。北疆和南疆灌木植物科的分布区类型均以世界广布型和北温带分布型为主,其中,在北疆灌木植物中这2个分布型科的数量分别占总科数的43.2%和32.4%、在南疆灌木植物中分别占总科数的50.0%和28.6%。北疆和南疆灌木植物属的分布区类型均以地中海区、西亚至中亚分布型和北温带分布型为主,其中,在北疆灌木植物中这2个分布型属的数量分别占总属数的26.9%和22.1%、在南疆灌木植物中则分别占总属数的31.7%和27.0%。北疆和南疆灌木植物中分别包含特有种15和8种,此外还包含一些珍稀濒危种类及古老的孑遗种。北疆与南疆灌木植物区系在科、属、种水平上的相似性系数分别为86.1%、69.4%和40.8%,表明在科、属水平上2个区域的灌木植物区系有较为密切的关系。研究结果显示:北疆和南疆灌木植物在种类组成、分布区类型和特有种数量等方面有一定差异,但均具有明显的温带性质,并形成了一系列适应于当地生态环境的生存策略。     

不同菊花品种根系、地上部和叶片相关指标分析及抗逆性评价

采用盆栽法对6个菊花(Chrysanthemum morifolium Ramat.)品种幼苗的根系和地上部相关指标及叶片光合和气体交换参数进行了比较和相关性分析;并基于叶片相对含水量、相对电导率、丙二醛含量和可溶性糖含量4个生理生化指标,采用隶属函数法对不同菊花品种幼苗的抗旱性和耐热性进行了评价.结果表明:不同菊花品种间幼苗的根系和地上部相关指标及叶片光合和气体交换参数存在一定差异.相关性分析结果表明:根系的大多数相关指标与株高呈显著(P<0.05)或极显著(P<0.01)正相关,但与茎粗和单株叶数却没有显著相关性;并且,单株的根体积、根鲜质量和干质量与单株地上部鲜质量呈极显著正相关(相关系数分别为0.598、0.642和0.599),与单株地上部干质量呈极显著或显著正相关(相关系数分别为0.736、0.606和0.553).主根长与净光合速率和蒸腾速率,平均根长与水分利用效率及单株根鲜质量与蒸腾速率呈显著正相关(相关系数分别为0.475、0.517、0.570和0.477);单株根干质量与蒸腾速率及根系活力与净光合速率和水分利用效率呈极显著正相关(相关系数分别为0.641、0.877和0.814).抗逆性评价结果表明:品种'南农红霞'('Nannong Hongxia')、'大白托桂'('Qx073')和'天使'('Angelina')的平均隶属函数值分别为0.93、0.93和0.72,据此判断这3个菊花品种的抗旱性最强;品种'馒头菊'('Cayman')和'南农红霞'的平均隶属函数值分别为0.82和0.70,据此判断这2个菊花品种的耐热性最强.综上所述,不同菊花品种幼苗的根系相关指标差异明显,并且根系生长状况能够影响地上部的生长和发育,品种'南农红霞'的抗旱性和耐热性均很强,具有较高的抗性育种价值.     

Cryogenic changes in proteases and antiprotease activities of buffalo (Bubalus bubalis) and cattle (Bos taurus) semen

The postthaw motility and fertility of buffalo and cattle semen is reduced when they are cryopreserved for artificial insemination. In the present study, an attempt was made to characterize the cryogenic changes in proteases and antiprotease activities (APA) of buffalo and cattle semen because these proteolysis regulators have been reported to be associated with sperm motility and fertility. Buffalo sperm demonstrated at least two major proteases of 45 and 42 kDa and three minor proteases of 95, 52, and 33 kDa. Similarly, cattle sperm demonstrated three major proteases of 62, 45, and 42 kDa and two minor proteases of 85 and 78 kDa. Buffalo seminal plasma demonstrated at least three major proteases of 78, 68, and 62 kDa and one minor protease of 98 kDa and cattle seminal plasma demonstrated one major protease of 68 kDa and two minor proteases of 78 and 75 kDa. Except for the 45 kDa protease, most of the previously mentioned proteases were found to be metalloproteinases. Compared with fresh sperm, cryopreserved buffalo and cattle sperm demonstrated a major protease band of 52/49 kDa and the activity of this protease reduced progressively with the duration of cryopreservation. On the contrary, compared with the fresh seminal plasma, cryopreserved buffalo and cattle semen extenders displayed the presence of a new protease band of 45 kDa and demonstrated that this protease activity was leaked from buffalo and cattle cryopreserved spermatozoa. Buffalo and cattle seminal plasmas displayed at least two major APA of 86 and 26 kDa. Compared with buffalo, cattle seminal plasma demonstrated significantly greater APA. Thus, the present study demonstrated the presence of an array of proteases and APA in buffalo and cattle semen and the activities of which changed during cryopreservation. The leakage of the specific protease activity and changes in the proteases and APA might be attributed to reduced motility and fertility of cryopreserved semen in these species.     

Effect of natural amino acids and sugars on cyclase activities in infusoria Tetrahymena pyriformis and Dileptus anser

Natural amino acids and sugars in intracellular eukaryotes are known to regulate adenylyl cyclase (AC) and guanylyl cyclase (GC) systems that control the most important cell processes. The goal of the present work consisted in study of effects of natural amino acids and sugars and some of their derivatives on AC and GC activities of infusoria Tetrahymena pyriformis and Dileptus anser. Methionine, arginine, lysine, and tryptamine stimulated basic AC activity of T. pyriformis, whereas alanine, thyrosine, and cysteine decreased it. Methionine, glycine, alanine, thyrosine, arginine, and to the lesser degree tryptamine and histidine stimulated AC of D. anser. The GC activity of T. pyriformis are increased in the presence of tryptamine, tryptophane, histidine, arginine, and lysine, whereas glycine and aspartic acid, on the contrary, decreased it. Tryptamine, tryptophan, leucine, glutamic acid, serine, histidine, and alanine stimulated the GC activity of D. anser. Glucose, fructose, and sucrose stimulated the basal AC activity of both infusorians and GC of T. pyriformis, with glucose and sucrose increasing AC of T. pyriformis twice, while that of D. anser 4.5 times. Lactose stimulated AC and GC of T. pyriformis and was inefficient with respect to the D. anser cyclases, whereas mannose and galactose did not affect the enzyme activities in both infusorians. The study of the chemotactic response of infusorians to amino acids and sugars indicates that involved in realization of this response can be signaling pathways both dependent on and independent of cyclic nucleotides. Thus, it has been established for the first time that several amino acids and sugars affect functional activity of enzymes with cyclase activity of the infusorians T. pyriformis and D. anser. This confirms the hypothesis that at early stages of evolution the large spectrum of comparatively simple natural molecules has a hormone-like action.     

史前人类的生存之火

用火是人类独有的行为能力,对人类的生存演化至关重要。用火熟食改善了人类的营养,导致人类生物特性发生一系列改变,人口、行为、社会关系和生存方式也发生相应变化。用火使人类获得更多的生存资源,并帮助人类改变工具与用具的材料特性,如对石料做热处理,进而发明了陶器和金属工具,开启了文明的历程。人类与火的互动是一个长期、曲折的过程,经历了偶尔利用自然火、时断时续对火控制和使用、有效保存火种乃至人工取火形成用火的日常习惯,进而发展到现代无所不在、不可或缺的复杂用火。人类用火被认为始于直立人的诞生,但目前提取到的证据指向150万年前。早期人类用火证据的提取和论证存在极大的困难和挑战,需要精细的野外工作,做高精度的遗址埋藏和遗物遗迹的空间分析,须采用现代科技手段和模拟实验对地层沉积物和燃烧物证做微形态、成分、色度、磁化率、微体植物化石等尽可能多的宏观和微观分析,排除自然因素的干扰,这样得出的结论才会坚实可信。本文介绍了人类用火的历史、作用和对用火证据提取与分析的思路、方法与技术,通过一系列案例阐述人类用火的方式、发展演化过程和考古学家为破译远古人类用火的谜团所做的努力和取得的成果,以期对这项意义重大但常被忽视的研究起到推动作用。     

Interaction of phosphorus and molybdenum in relation to uptake and utilization of molybdenum,phosphorus, zinc,copper and manganese by rice

Summary The effect of phosphorus and molybdenum alone and combined, on the uptake and utilization of Mo, Mn, Zn, Cu and P by rice (Var. IR-579) was studied in the greenhouse at varying levels of Mo (0, 2.5 and 5.0 ppm) and (0,100 and 200 ppm). Application of P increased the dry matter yield of shoot and root. Combined application of P and Mo increased the dry matter yield of shoot. Application of Mo increased the concentration of Mo and P in shoot. Applied P caused an increase in the concentration of Mo, Zn and P in shoot. Combined application of P and Mo resulted in an increase in concentration and uptake of Mo in shoot.     

T.l.c. enantiomeric separation of amino acids

Resolution of enantiomers is very important particularly in the fields of asymmetric synthesis, mechanistic studies, geochronology, studies of structure-function relationship of proteins, pharmacology, and medicine. Various chromatographic methods have replaced the classical fractional crystallization, seeding and enzymatic procedures. Of these, t.l.c. provides a direct, simple, and inexpensive method for resolution of enantiomers of amino acids and their derivatives. Ligand exchange, ion exchange, and molecular inclusion complexation have been the basis of t.l.c. resolution of enantiomers of amino acids and their derivatives. The innovation of new plate types, and methods of development and detection have renewed interest in the direct resolution of enantiomers of amino acids, their derivatives and a variety of other compounds by t.l.c. The present report provides an overview of some of the more recent approaches to the direct t.l.c. resolution of amino acids and their derivatives together with special advantages and scope of t.l.c.     

Morphology and histochemistry of ovarian changes in the field rat, Millardia meltada

A study has been made of the morphological and histochemical changes of the ovary of the field rat, Millardia meltada during its oestrous cycle and pregnancy. The follicular growth and atresia, ovulation and formation of corpora lutea occur throughout the year except severe winter months (December and January). Fluctuations in the follicular development occur on different days of the oestrous cycle and pregnancy. The granulosa cells show a progressive increase in their size in successive stages of follicle growth. The granulosae of normal follicles show some sparsely scattered lipid bodies which consist of phospholipids. Theca interna cells during follicular growth develop diffuse lipoproteins and lipid droplets consisting of triglycerides, phospholipids and cholesterol and/or its esters. The luteal cells of corpora lutea are formed by the granulosa cells as the theca interna cells degenerate and disappear. The fibroblast-like cells of thecal origin, alongwith the blood vessels, invade the luteal cell mass. The luteal cells during metoestrus, dioestrus and first half of pregnancy show abundant diffuse lipoproteins and a few lipid droplets composed mainly of phospholipids and some triglycerides, which are indicative of active steroidogenesis. The details of degenerative histological and histochemical alterations of corpora lutea during oestrous cycle and pregnancy are also described and discussed. Morphological and histochemical changes of follicular atresia are described. The granulosa cells of atretic follicle degenerate and disappear leaving behind theca interna cells which form patches of interstitial gland cells during the reproductive activity of the present rat. Interstitial gland cells show diffusely distributed sudanophilic lipoproteins and lipid droplets consisting of triglycerides, cholesterol and/or its esters and some phospholipids, which are indicative of steroidogenesis. The functional significance of histological and histochemical changes, which occur in various components of the ovary during oestrous cycle and pregnancy, has been discussed.     

5种野牡丹属植物花色素成分及影响花色呈色因子分析

为明确野牡丹属(Melastoma L.)植物花瓣的色素成分和呈色机理,为花色育种提供参考。以野牡丹(M.candidum)、白花野牡丹(M.candidum f.albiflorum)、印度野牡丹(M.malabathiricum)、白花印度野牡丹(M. malabathricumvar.alba)、毛稔(M.sanguinrum)5种野牡丹属植物材料,采用目测法、RHSCC比色法和色差仪测定花瓣表型,应用化学显色法、紫外分光光度法对花色素成分及含量进行初步分析与测定,通过徒手切片组织切片法观察花瓣表皮细胞的显微结构和分布特点,测定花瓣pH值、可溶性糖及可溶性蛋白含量等生理指标分析对花色的影响。结果显示,野牡丹属植物花瓣不含叶绿素和类胡萝卜素,紫罗兰色系主要含花青素苷和黄酮类化合物,白色系主要含黄酮类化合物。野牡丹和毛稔花色素分布于上、下表皮,印度野牡丹花色素分布于上、下表皮和栅栏组织,白花野牡丹和白花印度野牡丹花瓣没有发现色素积累;紫罗兰色系野牡丹上表皮细胞呈圆锥形突起,白色系野牡丹上表皮细胞呈不规则的扁平状,它们下表皮细胞全呈不规则的扁平状。野牡丹属植物花色明度L*随花瓣颜色变深而降低,明度L*与红度a*呈极显著负相关、与蓝度b*呈极显著的正相关。花瓣中花青素苷含量与其明度L*和蓝度b*呈显著负相关,pH值与花瓣红度a*呈现显著的负相关。研究表明,野牡丹属植物花色主要由花青素苷决定,花青素苷含量、色素分布、上表皮细胞形状等是引起花色呈现多样的主要因子。     

云南省新平县家鼠鼠疫疫原地小肠结肠炎耶尔森菌的调查分析

目的了解新平县家鼠鼠疫疫源地小肠结肠炎耶尔森菌的分布及病原学特征。方法采集家鼠盲肠、舌头和猪粪便、咽喉粘液以及腹泻患者粪便标本进行小肠结肠炎耶尔森菌的检测与分析。结果检测家鼠盲肠、鼠舌头、猪粪便、猪咽喉粘液物、腹泻患者粪便的标本数分别为722、722、467、237和107份,共分离到61株小肠结肠炎耶尔森菌,总检出率为2. 71%,5种标本的检出率分别为2. 63%、1. 39%、3. 85%、2.53%和7. 48%,差异有统计学意义（x^2= 16. 422,P = 0. 003）;分离株包括致病株10株、非致病株51株,有1A、2、3三种生物型和0：3、0：5、0：8等多种血清型,以及六种毒力基因型。猪、鼠、腹泻患者标本检出致病菌株数分别为9、1、0株。结论新平县家鼠鼠疫自然疫源地猪、鼠、腹泻患者是小肠结肠炎耶尔森菌的重要宿主,分离菌株具有遗传多样性,猪、鼠是小肠结肠炎耶尔森菌病的主要传染源。     

黄土高原小叶杨与其他树种枯落叶混合分解对土壤性质的影响

将小叶杨分别与其他11个树种枯落叶粉碎混合后进行室内分解培养,分析不同树种枯落叶混合分解对土壤性质的影响及其相互作用.结果表明:12个树种枯落叶单独混土分解均明显提高了土壤脲酶、脱氢酶、磷酸酶活性和有机质、碱解N含量,但对土壤速效P含量和土壤阳离子交换量(CEC)的影响差异较大,其中柠条和紫穗槐枯落叶改善土壤性质的效果明显.小叶杨分别与油松、侧柏、刺槐、白榆枯落叶混合分解,对土壤微生物数量的影响存在相互促进作用;小叶杨分别与侧柏、柠条枯落叶混合分解对土壤有机质、速效P、速效K含量和CEC的影响存在相互促进作用,但对土壤大部分酶活性的影响却存在相互抑制作用;小叶杨与落叶松枯落叶混合分解对土壤多数酶活性和养分含量的影响存在相互促进作用,而与樟子松枯落叶混合分解时则有抑制作用.总体上,小叶杨分别与白榆、油松、落叶松和刺槐枯落叶混合分解可促进土壤性质的改善,而与侧柏、柠条、樟子松、沙棘和紫穗槐枯落叶混合分解时则相互抑制.     

Mold flora and aflatoxin contamination of stored and cooked samples of pearl millet in the Paharia tribal belt of Santhal paragana, Bihar, India.

Stored and cooked samples of pearl millet (Pennesetum typhoides), which is regularly consumed as food by the Paharia tribe in the hilly regions of Santhal Pargana, Bihar State, India, that were harvested in January 1989 were analyzed for mold flora, natural occurrence of Aspergillus flavus and A. parasiticus, and incidence and levels of aflatoxin B1. Of the 22 fungal species isolated, A. flavus and A. parasiticus were the predominant species (63.8%) during the rainy season, followed by other species of Aspergillus, Penicillium, Fusarium, Rhizopus, Helminthosporium, and Curvularia. Screening of 169 A. flavus and A. parasiticus strains showed that 59 of them were toxigenic, producing various combinations of aflatoxins B1, B2, G1, and G2. The amounts of aflatoxin B1 ranged between 4 and 30 mg/100 ml of liquid medium. Analysis of stored and cooked samples also revealed a high incidence and alarming levels of naturally produced aflatoxin B1. Forty-nine of 75 stored and 16 of 38 cooked samples contained various combinations of aflatoxins. The levels of aflatoxin B1 ranged between 17 and 2,110 ppb in stored samples and 18 and 549 ppb in cooked samples. The correlation of insect damage with A. flavus and A. parasiticus incidence and quantity of aflatoxin B1 was found to be insignificant.     

Local and landscape drivers of biodiversity of four groups of ants in coffee landscapes

Agriculture of varying management intensity dominates fragmented tropical areas and differentially impacts organisms across and within taxa. We examined impacts of local and landscape characteristics on four groups of ants in an agricultural landscape in Chiapas, Mexico comprised of forest fragments and coffee agroecosystems varying in habitat quality. We sampled ground ants found in leaf litter and rotten logs and arboreal ants found in hollow coffee twigs and on tree trunks. Then using vegetation and agrochemical indices and conditional inference trees, we examined the relative importance of local (e.g. vegetation, elevation, agrochemical) and landscape variables (e.g. distance to and amount of nearby forest and rustic coffee) for predicting richness and abundance of ants. Leaf litter ant abundance increased with vegetation complexity; richness and abundance of ants from rotten logs, twig-nests, and tree trunks were not affected by vegetation complexity. Agrochemical use did not affect species richness or abundance of any ant group. Several local factors (including humus mass, degree of decay of logs, number of hollow twigs, tree circumference, and absence of fertilizers) were significant positive predictors of abundance and richness of some ant groups. Two landscape factors (forest within 200 m, and distance from forest) predicted richness and abundance of twig-nesting and leaf litter ants. Thus, different ant groups were influenced by different characteristics of agricultural landscapes, but all responded primarily to local characteristics. Given that ants provide ecosystem services (e.g. pest control) in coffee farms, understanding ant responses to local and landscape characteristics will likely inform farm management decisions.