AN ARCHAIC SLIME MOULD IN BALTIC AMBER

Abstract:  Several sporocarps of a slime mould are preserved on a plant fragment in a piece of Baltic amber (Tertiary, Eocene). The fossil is assigned to the extant genus Protophysarum (Myxomycota sensu stricto , Physarales) and described as P. balticum sp. nov. It is the third record of fossil sporocarps of a slime mould and the second record of the subclass Myxogasteromycetidae. All three records of fossil sporocarps are inclusions in Baltic amber. The find provides new insights regarding the occurrence and phylogeny of myxomycetes in the Palaeogene.     

论长城系微化石群的真核生物意义

本文主要以燕山地区长城系页岩相微化石群为基础,通过与现代生物形态标志的对比,论证了在18亿年前真核藻类即已繁盛发育,其中既包括有原始的绿藻和甲藻,也有低级的真菌,还可能有原始类型的褐藻,至于真核生物出现的时间则可追溯到古元古代。根据已知资料的综合,按体制阶段的发展规律给出了绿藻、甲藻以及褐藻的可能的各自发展路线,可供探讨藻类起源与演化时参考。     

DETECTION OF TYPE A BOTULINAL TOXIN-PRODUCING ORGANISMS SUBCULTURED FROM CHEESE USING AN AMPLIFIED ELISA SYSTEM

Mascarpone cheese implicated in a botulism outbreak was examined for preformed and cultural botulinal toxins using the mouse bioassay. The cheese was also assayed for cultural toxins and for the most probable number (MPN) of toxin-producing organisms/g using an amplified ELISA. No preformed botulinal toxins were discovered in the cheese samples (pH range 5.84-5.86) using the mouse bioassay. However, after cheese subculture in tryptone-peptone-glucose-yeast extract broth, type A botulinal toxin-producing organisms that formed more than 10,000 MLD (mouse lethal dose)/mL in culture were detected. The ELISA results also revealed that type A toxin was present in the culture with a sensitivity of ∼ 10 MLD/mL. The MPN of type A toxin-producing organisms/g in 12 cheese samples examined ranged from < 0.3-9.33. No ELISA cross-reactivity was noted between the type A toxic cultures and other types (B, E, or F). The ELISA sensitivity was ∼5 MLD/mL casein buffer using purified type A neurotoxin. The advantages of the ELISA test are that the toxin type and approximate lethal dose can be determined within one day compared to the mouse bioassay which takes 3–5 days.     

松花江水系水生生物的初步研究

水生生物不但是水生态系统的重要组成部分,而且是鱼类的天然饵料基础,对渔业和经济都具有重要意义。国内开展这方面研究工作虽然较多,但迄今尚未见到松花江水系较系统的研究报告。为此将1983—1984年的初步研究结果简要报道如下。       

经济生态学原则在工农业建设中的应用

经济社会是以人类经济活动为中心的经济生态系统,包括复杂的物质代谢过程和心理因素。社会发展意味着社会内部和社会之间经济结构的深刻变化,近年来许多国家由于在高速度经济发展过程中,忽视了生态系统的若干基本规律,对自然资源及人类生活环境造成严重不利影响,迫使这些国家不得不面临他们的自然生态系统所拥有的资源,养活不了日益膨胀     

OLIGONUCLEOTIDES AS CODING MOLECULES IN AN ANTI-COUNTERFEITING SYSTEM

Due to the growing numbers of counterfeited products on the world market, there is a huge demand for new and forgery-proof marking systems. We developed a unique system using “molecular beacons” with well adapted thermodynamic parameters. This marking system consists of the three components: DNA tag (a label or directly printing), detection pen (contains the “molecular beacon” solution), and DNA-scanner (reads the specific signal triggered by the detection pen even at daylight). The vast coding capacity of DNA combined with the highly specific signal offers a degree of security that is unmatched by conventional identification technologies.     

CONVERSION EFFICIENCIES IN HETEROTROPHIC ORGANISMS

1. The maximum possible efficiency at which living systems are able to convert input nutrients to their own biomass is between 70 and 80 %. 2. Conversion efficiency in bacteria, protozoa and metazoan cells in culture approximates more closely to 60%. 3. Conversion efficiency during embryonic development begins below 60% and rises above this level in the later stages. 4. Very young, post-natal organisms have high net efficiencies; 50 to 70% in homeotherms and 50 to 80 % in poikilotherms. 5. In cellular systems, capable of proliferation, conversion efficiency is independent of food supply. This means that conversion is directly dependent on nutrient supply. 6. Control of growth at the tissue level may occur through the control of the supply of nutrients to the tissues and its entry into the cells. 7. Compensatory growth, after and during undernutrition, involves increased absorption efficiency and reduced metabolic costs.     

染色质在非洲爪蟾卵的无细胞系统中形成组装核的研究

从大鼠肝、鸡肝提取了染色质并从受精未孵育鸡蛋胚下表层卵黄颗粒提取了染色质,在荧光显微镜和电子显微镜下观察了这些染色质在无细胞系统中形成的组装核;研究二阶钙镁离子对形成组装核的影响。在有ＡＴＰ再生系统存在的无细胞系统中,围绕染色质能形成与间期细胞核相似的组装核;二价钙离子不利于形成组装核,而二价镁离子是形成组装核所必须的,但过高浓度的镁离子对形成组装核有抑制作用。     

SLIME SUBSTANCE AND STRANDS IN SIEVE ELEMENTS

Studies of the secondary phloem of 6 species of woody dicotyledons revealed that slime is not normally dispersed throughout the vacuole of mature sieve elements, but occurs in the form of discrete strands that traverse the cell and run from cell to cell through the sieve-plate pores. As many as 5 fine strands, each measuring less than 0.5μ in diameter, were observed in a single pore. Less than 30% of pore area was occupied by strands. Thus, the pores are mostly open, and intervacuolar continuity exists between cells. These structural characteristics of pores offer strong support for the concept of mass flow.     

SPATIAL PATTERNING AND COMPETITION IN AN ASPEN-WHITE PINE SUCCESSIONAL SYSTEM

The spatial patterning of and competition between established large-toothed aspen (Populus grandidentata) and invading white pine (Pinus strobus) were examined in a 65-yr-old forest system at the AuSable Trails Institute of Environmental Studies, Kalkaska County, Michigan. Density, diameter, and distance measures were recorded for tree species on two 40 × 40 m grids containing 64 quadrats each 5 × 5 m. Several indices of dispersion were used to assess pattern and regression analysis of nearest neighbor distance to tree diameter provided an index of competition. The results indicate strong aggregation for both aspen and pine on a large scale, but regularity of pattern for pines in relation to their nearest neighbor. This regularity appears to be due to competition with established aspens and suggests that the spatial patterning of the aspens acts to control the spacing and subsequent development of the invading white pines.     

SEASONAL VARIATIONS IN PHYTOPLANKTON COMMUNITIES OF AN EPHEMERAL POND SYSTEM IN SOUTHEASTERN VIRGINIA

Most industrial and agricultural enterprises of the Kamchatsky district are situated along the coast of the Avacha Bay and its river drainage. Intensive water pollution resulted in extreme deterioration of the bay's ecology. The destruction of macrophytobenthos under the influence of pollution was investigated. Materials were regularly collected at the same sampling sites in different seasons of the year from 1988 up to 1999. Analysis of our data allowed us to determine directions of long-term changes of species composition and macrophytobenthos structure, speed of degradation of different types of vegetational communities and reasons for all these processes. The Avacha Bay's flora consisted of more than 160 species up to 1970s, including species belonged to 104 genera, 47 families, 23 orders, 3 divisions (30 Chlorophyta, 48 Phaeophyta, 82 Rhodophyta). Flora of the internal part of the bay differed from that of the bay's mouth and consisted of 143 and 146 species, respectively. Presently, the whole flora of the bay (internal part+ throat) includes only 94 species. Along the urban coast 18 poly- and mesosaprobious species are found only. They are characterized by small sizes, low productivity and short life cycles. Most of them are ephemeral with a primitive morphology. The responsive reaction of algae to pollution resulted in decreases in size and weight of the thalli, and appearance of anomalies of development. Laminaria bongardiana was used as a bioindicator. The changes of weight and sizes of its plants allow us to determine degree of the pollution in different parts of the coast of the Avacha Bay.     

AN ENZYME SYSTEM IN RAT BRAIN NUCLEI INCORPORATING AMP INTO POLYADENYLATE

Abstract— The presence of an ATP polymerizing system has been demonstrated in rat brain nuclei. The enzymic activity was not dependent on DNA, and poly A itself primed the incorporation of AMP into polyadenylate. Poly U did not prime the incorporation of AMP. The incorporation obtained in the presence of ribosomal RNA from rat brain as primer was mainly attributable to terminal attachment of AMP. Actinomycin and inorganic ortho-phosphate had no effect on the enzymic activity, however, inorganic pyrophosphate, ammonium sulphate and nucleoside triphosphates (GTP, CTP and UTP) were inhibitory. The same nuclear extract of brain, used for the synthetic reaction producing poly A, also degraded the polynucleotide to yield adenosine mono, di and triphosphates.