Mutants of Arabidopsis lacking starch branching enzyme II substitute plastidial starch synthesis by cytoplasmic maltose accumulation

Three genes, BE1, BE2, and BE3, which potentially encode isoforms of starch branching enzymes, have been found in the genome of Arabidopsis thaliana. Although no impact on starch structure was observed in null be1 mutants, modifications in amylopectin structure analogous to those of other branching enzyme II mutants were detected in be2 and be3. No impact on starch content was found in any of the single mutant lines. Moreover, three double mutant combinations were produced (be1 be2, be1 be3, and be2 be3), and the impact of the mutations on starch content and structure was analyzed. Our results suggest that BE1 has no apparent function for the synthesis of starch in the leaves, as both be1 be2 and be1 be3 double mutants display the same phenotype as be2 and be3 separately. However, starch synthesis was abolished in be2 be3, while high levels of alpha-maltose were assayed in the cytosol. This result indicates that the functions of both BE2 and BE3, which belong to class II starch branching enzymes, are largely redundant in Arabidopsis. Moreover, we demonstrate that maltose accumulation depends on the presence of an active ADP-glucose pyrophosphorylase and that the cytosolic transglucosidase DISPROPORTIONATING ENZYME2, required for maltose metabolization, is specific for beta-maltose.     

制备型高效液相色谱法分离蛋白质的研究

生物工程的发展,特别是生化制品下游处理技术的兴起,对现代分离科学提出了更高的要求,研究和开发各类生化物质特别是活性生物大分子的分离纯化技术,已成为一项十分重要的研究课题。在现有的分离技术中,液相色谱,尤其是80年代在分析型高效液相色谱(HPLC)基础上兴起的制备型HPLC,在大规模分离纯化生物活性物质特别是蛋白质方面已显示出巨大的应用潜力,引起了各国研究者的高度重视^[1-5].本文利用自行设计的制备型HPLC分离装置,对牛血清白蛋白(BAS)和牛血清红蛋白(HG)的制备分离过程进行了实验研究,着重考虑了流动流速、柱超载方式、柱长等因素对BAS和HG分离度的影响。     

Ethical and regulatory issues arising from proteomic research and technology

Over the last two decades, medical research has begun to make extensive use of products of human origin in therapeutics, oncology, and most recently, in genetic diseases. This has raised many ethical issues involving patient rights, including issues of consent. Besides informed consent, researchers should address several topics when designing studies using human tissues. Reward for the patient should be kept minimal. Sample transfer should be organized along non-profit lines, at least in Europe. Sampling procedures should be at no risk for human volunteers, and at minimal risk for patients. Biosafety aspects should be addressed, in particular when international collaborations are intended or when collaboration is existing between academia and industry. Regulations on importation and exportation of human tissues should be observed. Data acquisition and storage should be addressed in accordance with national data protection regulations, in particular when using computerized databases. If follow-up information is to be taken, the authorization for such information should be requested. The right for patient's information (or for no information) on the research results should also be addressed. The issues of validation and patenting should be also solved, usually by informing the patient that he/she will have no commercial rights on potential research results. The patient should be told if the samples are transferred to another research laboratory or private company. Samples and related data should be destroyed on request at any time point during the course of the study. If possible, traceability of the donor should be ensured.     

Assessment of the potential germ cell mutagenicity of industrial and plant protection chemicals as part of an integrated study of genotoxicity in vitro and in vivo

An approach is described that enables the germ cell mutagenicity of chemicals to be assessed as part of an integrated assessment of genotoxic potential. It is recommended, first, that the genotoxicity of a chemical be defined by appropriate studies in vitro. This should involve use of the Salmonella mutation assay and an assay for the induction of chromosomal aberrations, but supplementary assays may be indicated in specific instances. If negative results are obtained from these 2 tests there is no need for the conduct of additional tests. Agents considered to be genotoxic in vitro should then be assessed for genotoxicity to rodents. This will usually involve the conduct of a bone marrow cytogenetic assay, and in the case of negative results, a genotoxicity test in an independent tissue. Agents found to be non-genotoxic in vivo are regarded as having no potential for germ cell mutagenicity. Agents found to be genotoxic in vivo may either be assumed to have potential as germ cell mutagens, or their status in this respect may be defined by appropriate germ cell mutagenicity studies. The basis of the approach, which is supported by the available experimental data, is that germ cell mutagens will be evident as somatic cell genotoxins in vivo, and that these will be detected as genotoxins in vitro given appropriate experimentation. The conduct of appropriate and adequate studies is suggested to be of more value than the conduct of a rigid set of prescribed tests.     

中国东北草场的研究

中国东北包活辽宁、吉林、黑龙江三省及内蒙东部,其草场丰富多样,包括沼泽、草甸、草甸草原及草原,从东到西,可划分3个区:Ⅰ.穆棱-三江平原的草甸、沼泽草场, Ⅱ.松辽平原的草甸草原草场, Ⅲ.蒙古高原的草原草场。文内不仅论述了各区草场的植被组成及分布规律,并为合理经营、利用与保护不同类型的草场,提供理论依据及采取有效措施的途径。     

Free energy and time economy for the mutual selection of monomers in biosynthesis, primarily protein synthesis

The starting point of this work is the fact that the correction of errors in biosynthesis must be paid for by an increased dissipation (free energy loss) or a time delay. Further, a low accuracy is wasteful in this respect as the cell then produces a number of non-functioning products with a significant "production cost". One can then look for the situations of best "economy" for the selection processes. This is particularly obvious in reciprocal selections, where in some cases a substrate A shall be selected but discriminated against a competitor B, and in other cases, the opposite is true, B shall be selected with A as a competitor. It can be expected only in certain symmetric situations that these reciprocal selections are made in an equal way. Because one substrate shall be selected more often or it may be more relevant for the product, it may occur in higher concentrations and/or be selected more accurately (at a higher cost). The opposite selection may then be less accurate. The work studies various aspects of this.     

“食品微生物学”微课的开发设计与制作

微课作为一种以学习者为中心设计的可视化学习资源,因其短小精悍的特点已逐渐受到移动学习者的欢迎。本文介绍"食品微生物学"微课设计开发与制作方面的心得与体会。首先应有独具匠心的教学设计,在此基础上再采用有效的微课制作方式。教学设计时应精心选题,力求快速有效切题,线索清晰,亮点突出,收尾干净利落,还应树立危机意识。微课制作时要根据主题选择合适的微课表现形式,制作有视觉美感的PPT,录制清晰稳定的图像,最后剪辑、美化、合成得到微课视频。     

A total approach in ergonomics is a must to attain humane, competitive and sustainable work systems and products

Globalization brings along complexity, competition and change as anticipated by working in teams, quality enhancement of human resources and a change of mind-set to be more holistic in approaches. Enhancement of expertise, widening of the horizon, developing added values as well as preparedness to carry out management of the future have to be built and developed. Conditioning and customizing programs through formal and informal education and training should also be carried out in bridging existing gaps, filling needs and solving key problems. New proper and appropriate curricula must be developed together with encouraging the change of mind-set. It is essential to attain the highest capabilities to work in a team and to think and act holistically, as well as to enhance human relations capabilities in communicating the research results. By so doing, the gaps between research and implementation and between theory and practice need to be bridged; the felt real needs of the target groups could thus be filled; and the root causes of the problems faced in any activity could be solved in a sustainable manner. In implementation, a SHIP (Systemic, Holistic, Interdisciplinary and Participatory) approach must be conducted for identifying, analyzing and solving the problems so as to attain sustainable results. In defining the technology being used, it must be comprehensively assessed through six criteria so that it can be technically, economically, ergonomically and socio-culturally sound, save energy and preserve the environment. Through this total approach, work organization and work systems and their products are expected to be more humane (healthier, safer, comfortable, efficient), competitive and sustainable, as prerequisites for survival and continual development.     

Interactive robots in experimental biology

Interactive robots have the potential to revolutionise the study of social behaviour because they provide several methodological advances. In interactions with live animals, the behaviour of robots can be standardised, morphology and behaviour can be decoupled (so that different morphologies and behavioural strategies can be combined), behaviour can be manipulated in complex interaction sequences and models of behaviour can be embodied by the robot and thereby be tested. Furthermore, robots can be used as demonstrators in experiments on social learning. As we discuss here, the opportunities that robots create for new experimental approaches have far-reaching consequences for research in fields such as mate choice, cooperation, social learning, personality studies and collective behaviour.     

Marital therapy for the elderly.

Little attention has been paid to marital therapy for the elderly in spite of its relevance to morale and emotional problems. Physical illness is of particular significance in altering the dynamics of the marital relationship. Retirement and financial problems, as well as changes in sexual activity and gender roles, are also important. However, radical changes in patterns of behaviour cannot be expected. Therapeutic techniques must be altered for this age group, and the therapist must be active, giving and concretely helpful. As with therapy for younger couples, children may need to be involved in the therapy sessions. Family physicians should be a main source of help for marital problems among the elderly. However, because problems related to countertransference must be faced, working with the elderly will not be for everyone.     

Peptide YY in gastrointestinal disorders

The changes in PYY in several gastrointestinal disorders and their possible clinical implications are reviewed. The changes in PYY seem to be an adaptive response to alterations in the patho-physiological condition caused by the disease. This becomes evident in gastrointestinal disorders such as diabetes gastroenteropathy, inflammatory bowel diseases, celiac disease, systemic sclerosis and post-intestinal resection state. On the other hand, changes in PYY in chronic idiopathic slow transit constipation appear to be primary and could be one of the etiologic factors of the disease. PYY does not seem to be involved in colorectal carcinoma. Although gastrointestinal dysmotility in neuro-muscular diseases is evident, PYY is not affected. The changes in PYY in gastrointestinal disorders could be beneficial in clinical practice. Thus, in cases where an increase or decrease in PYY is desirable, a diet that increases or decreases PYY synthesis and release can be followed, or a receptor agonist or antagonist can be utilized.     

Differentiation genes: are they primary targets for human carcinogenesis?

In spite of extensive research in molecular carcinogenesis, genes that can be considered primary targets in human carcinogenesis remain to be identified. Mutated oncogenes or cellular growth regulatory genes, when incorporated into normal human epithelial cells, failed to immortalize or transform these cells. Therefore, they may be secondary events in human carcinogenesis. Based on some experimental studies we have proposed that downregulation of a differentiation gene may be the primary event in human carcinogenesis. Such a gene could be referred to as a tumor-initiating gene. Downregulation of a differentiation gene can be accomplished by a mutation in the differentiation gene, by activation of differentiation suppressor genes, and by inactivation of tumor suppressor genes. Downregulation of a differentiation gene can lead to immortalization of normal cells. Mutations in cellular proto-oncogenes, growth regulatory genes, and tumor suppressor genes in immortalized cells can lead to transformation. Such genes could be called tumor-promoting genes. This hypothesis can be documented by experiments published on differentiation of neuroblastoma (NB) cells in culture. The fact that terminal differentiation can be induced in NB cells by adenosine 3',5'-cyclic monophosphate (cAMP) suggests that the differentiation gene in these cells is not mutated, and thus can be activated by an appropriate agent. The fact that cAMP-resistant cells exist in NB cell populations suggests that a differentiation gene is mutated in these cancer cells, or that differentiation regulatory genes have become unresponsive to cAMP. In addition to cAMP, several other differentiating agents have been identified. Our proposed hypothesis of carcinogenesis can also be applied to other human tumors such as melanoma, pheochromocytoma, medulloblastoma, glioma, sarcoma, and colon cancer.     

Possible evolutionary futures for mankind

1. With the development of techniques of gene transfer, human genetic defects such as sickle cell anaemia, phenylketonurea, cystic fibrosis, haemophilia, Huntington's chorea, etc. will be eliminated. Ninety nine percent of humans in the year 2500 will be much the same as at present, but healthier. 2. Studies of Comparative Biochemistry and Physiology show that many strategies have been developed in the Animal Kingdom that could be advantageous in furthering human survival. Some of these strategies are discussed in the present article. 3. Commensal algae that will live in the epidermis of domestic animals (pigs, goats, cattle) will be developed enabling these animals to live in dry environments with minimal demands for food and water. Once successful in domestic animals, the algae could be adapted to live in some humans, i.e. the "Green Man". 4. Commensal protozoa and bacteria that digest cellulose and lignin will be developed so that they can live in the human gut and convert the material to sugars, volatile fatty acids and amino acids that can be absorbed and metabolized by Man, thus making many inexpensive vegetable food resources available. 5. Mammalian embryos will be able to develop through to full term in vitro in a cleidoic egg; and the in vitro fertilized egg will have to depend on finding a surrogate mother. 6. Some people will have an altered pattern of sexual activity. Many patterns will be available; one suggested here is of protogynous hermaphroditism, i.e. the individuals would be female for the first 30 years of life and male for the remaining years.(ABSTRACT TRUNCATED AT 250 WORDS)     

INTESTINAL OBSTRUCTION COMPLICATING ACUTE PERFORATIVE APPENDICITIS

Upon preoperative diagnosis of acute small bowel obstruction, without an obvious cause, acute perforative appendicitis must be considered. Reevaluation of the history and careful reexamination of the physical findings with that diagnosis in mind should be carried out. If appendiceal disease is likely, maximum antibiotic therapy must be begun immediately along with the administration of fluids, electrolytes and other corrective therapy. A mercury-weighted small bowel tube should be inserted and every effort made to advance it into the small bowel before operation. Operative treatment should be restricted to the least possible. A McBurney incision is best unless wider operation is indicated. If an abscess is present, drainage alone may be the procedure of choice. Severely distended and decompensated small bowel must be decompressed, for if not relieved it can be the cause of death in acute perforative appendicitis. Decompression may be accomplished either by small bowel intubation with continuous suction or by enterotomy and aspiration. If not relieved, small bowel distention will be the mechanism responsible for death in a large percentage of patients with acute perforative appendicitis.     

THE INTERNAL ORGANIZATION OF MITOCHONDRIA

Sections of mitochondria in Paramecium and Euplotes present a consistent pattern. The mitochondrion in these cells can be conceived of as a twisted mass of closely compacted tubules. Two general kinds of substances can be recognized: the electron-dense that borders the lumen of the tubule, and the less dense that forms the continuum. In sections of mitochondria in rat kidney and snail oviduct, tubular internal organization can be recognized. In the same organs, mitochondria with lamellar internal structure can be demonstrated. The thesis is developed that the mitochondrion is a structure capable of differentiation and change, and that developmental continuity among the different kinds may exist. Mitochondria that appear to be different may be quite similar basically; mitochondria that appear to be similar in structure may be different in other ways. The tubule is proposed as the most basic of the presently recognized mitochondrial structures.     

Setting Up International (Adversary) Regimes in the South China Sea: Analyzing the Obstacles from a Chinese Perspective

If the sovereignty issue can be shelved, solved, or resolved, the six claimant states of the South China Sea will have to establish a series of international regimes. The following questions need to be answered: Do all the claimants understand the concept of international regimes? Would the regimes be imposed? Would there be hegemon(s) in the South China Sea? If so, which country or multiple entities will be involved? What would be the outcome of having international regimes in the South China Sea? Can the experience elsewhere be applied to the South China Sea?     

The Gene Construction Kit: a new computer program for manipulating and presenting DNA constructs

The Gene Construction Kit is a new tool for manipulating and displaying DNA sequence information. Constructs can be displayed either graphically or as formatted sequence. Segments of DNA can be cut out with restriction enzymes and pasted into other sites. The program keeps track of staggered ends and notifies the user of incompatibilities and offers a choice of ligation options. Each segment of a construct can have its own defined thickness, pattern, direction and color. The sequence listing can be displayed in any font and style in user defined grouping. Nucleotide positions can be displayed as can restriction sites and protein sequences. The DNA can be displayed as either single- or double-stranded. Restriction sites can be readily marked. Alternative views of the DNA can be maintained and the history of the construct automatically stored. Gel electrophoresis patterns can be generated and can be used in cloning project design. Extensive comments can be stored with the construct and can be searched rapidly for key words. High quality illustrations showing multiple editable constructs with added graphics and text information can be generated for slides, posters or publication.     

Asthma in children--problems in diagnosis

Bronchial asthma in children may be difficult to diagnose. Education of the parents regarding allergic conditions, specifically bronchial asthma, is exceedingly important in order to assure satisfactory treatment and clinical results. Chest symptoms of unexplained origin in early life should immediately arouse suspicion of allergic disease. Other causes of asthmatic symptoms must be borne in mind and excluded before a positive diagnosis of bronchial asthma is established. Of the many factors to be considered in investigating a child with asthma, a comprehensive history is most essential. The climate to which the patient is exposed and the psychic influences must be taken into account. Physical examination, x-ray films and laboratory procedures should be carefully executed. Skin testing, especially with food allergens, should not be relied upon to give all the information in allergic disease. Some form of diet trial, such as elimination diets, should be used if sensitivity to food is suspected.     

Minor tranquillizers in somatic disorders.

Conclusive evidence of improved outcome due to adjunctive anxiolytic therapy in some somatic conditions is lacking. However, such therapy may facilitate patient management without being "curative". The resulting improved feeling of well-being may be of value in the management of gastrointestinal disorders, migraine and myocardial infarction. Negative effects may be observed in acute respiratory conditions, especially during acute exacerbations of chronic conditions, with the administration of benzodiazepines; hence they should be used with caution. The use of these agents in treating persons with hypertension seems to be of no value and may even be detrimental. Careful evaluation of each case is desirable, and treatment should be planned with its termination in mind.     

The biosynthesis of biologically active proteins in mRNA-microinjected Xenopus oocytes

The basic properties of mRNA-injected Xenopus oocytes as a heterologous system for the production of biologically active proteins will be reviewed. The advantages and limitations involved in the use of this in ovo system will be discussed, as compared with in vitro cell-free translation systems and with in vivo microinjected mammalian cells in culture. The different assay systems that have been utilized for the identification of the biological properties of oocyte-produced proteins will be described. This section will review the determination of properties such as binding of natural ligands, like heme or alpha-bungarotoxin; immunological recognition by antibodies; subcellular compartmentalization and/or secretion; various enzymatic catalytic activities; and induction in ovo of biological activities that affect other living cells in culture, such as those of interferon and of the T-cell receptor. The limitations involved in interpretation of results obtained using mRNA-injected oocytes will be critically reviewed. Special attention will be given to the effect of oocyte proteases and of changes in the endogenous translation rate on quantitative measurements of oocyte-produced proteins. In addition, the validity of the various measurement techniques will be evaluated. The various uses of bioassays of proteins produced in mRNA-injected Xenopus oocytes throughout the last decade will be reviewed. Nuclear and cytoplasmic injections, mRNA and protein turnover measurements and abundance calculations, and the use of in ovo bioassays for molecular cloning experiments will be discussed in this section. Finally, potential future uses of the oocyte system in various fields of research, such as immunology, neurobiology, and cell biology will be suggested.