METAMORPHOSIS OF THE LARVA OF THE POLYCHAETE ARENICOLA CRISTATA. MORPHOLOGY OF THE ‘HOUR-GLASS’ STAGE

The constricted ‘waist’ of the metamorphosing larva of the polychaete Arenicola cristata is described, using light and electron microscopy. The constriction is shown to be the consequence of the discharge and collapse of a post-trochal ring of epithelial cells which remain as functional components of the post-metamorphic juvenile. Morphological differentiation of neuro-effector and interneuronal contacts is initiated at this time. Muscular and neural changes are discussed in terms of their role in effecting metamorphosis.     

THE GROWTH OF THE STEM TIP OF KALANCHOËU CV. ‘BRILLIANT STAR’

Stein , Diana B. and o . L. Stein . (Montana State U., Missoula.) The growth of the stem tip of Kalanchoë cv. ‘Brilliant Star.‘ Amer. Jour. Bot. 47 (2) : 132—140. Illus. I960.–The purposes of this investigation were (1) to define as clearly as possible the events in the shoot apex and its immediate derivatives during the ontogeny of the shoot; and (2) to determine the changes which occur during the transition from a vegetative to a reproductive meristem. Rate of leaf production in Kalanchoë is basically constant. The rate of leaf growth subsequent to the early primordial state is, however, dependent on the age of the plant and on the environment in which the plant is grown. By keeping these factors constant a correlation can be demonstrated between the size of the youngest visible leaf and the microscopic primordia. Throughout its ontogeny the general architecture of the shoot apex remains essentially the same. Two tunica layers cover the corpus in the vegetative shoot apex, and even in the flowering meristem these 2 layers can be detected. The apex is essentially flat and blends into the adjacent leaf primordia early in the plastochron. About 10 days after flower induction has been started the apex changes its form to a dome, primarily by increased cell division. At the same time the rate of elongation of the youngest internodes increases thus placing the flowering stem tip atop an elongated stem. Axillary development is ultimately responsible for the development of a dichasium.     

A MORPHOLOGICAL AND HISTOLOGICAL STUDY OF THE TOMATO MUTANT ‘CURL’

The dominant tomato mutant ‘Curl’ differs from normal plants in several striking respects including the following: misshapen laminar structures such as leaves, sepals, and petals; stunted petiole and rachis; and persistent growth of blade and stem tissue from the adaxial surface of the rachis. These tissues as well as others which appear morphologically normal show gross histological abnormalities. Also evident in sections of mutant tissue is the appearance of areas containing numerous crystalline inclusions and a lack of bodies showing a stainable starch reaction in palisade and mesophyll of leaves and in endodermis and pith cells of the stem.     

THE ‘ MEDITERRANEAN ’RAMALINA PANIZZEINORTH OF THE ALPS: MORPHOLOGICAL,CHEMICAL AND rDNA SEQUENCE DATA

Ramalina panizzei De Not. is reported from Switzerland and north of the Alps for the first time. Recent collections and thalli found amongst specimens ofR. fastigiata(Pers.) Ach. are described; the species is obviously not restricted to the Mediterranean. The confusion in several herbaria around this and related corticolous species, particularlyR. subgeniculataNyl. andR. fastigiata, can be traced back to imprecise original and subsequent diagnoses, all of which lack a clear species delimitation. Similarities and differences of these species are discussed. In addition, sequences from the rDNA ITS regions were determined for two individuals ofR. panizzeiand two ofR. fastigiata, including one of each from a site where both species grow intermixed. Kimura 2-parameter genetic-distance estimates indicate thatR. panizzeiandR. fastigiataare as different from each other as either is from the reference speciesR. siliquosa(Hudson) A. L. Sm.s.l.A broad-based taxonomic revision of involved species is not possible due to the limited number of analyses, but the results demonstrate the potential for using DNA sequence data to investigate species-level questions in lichens. Based on morphology, chemistry, and DNA sequence data,R. panizzeiis retained as a distinct species.     

Special Issue on‘‘Computational Cardiology’’

<正>We are pleased to announce a special issue on‘‘Computational Cardiology’’of the journal Genomics,ProteomicsBioinformatics(GPB),aiming to provide a platform for high-quality papers focusing on the topic and we invite submissions for this special issue(to be published in the fall of 2015).Dr.Benjamin Meder(University of Heidelberg and German Center for Cardiovascular Research–DZHK     

Special Issue on‘‘Biomarkers for Diseases’’

<正>The journal Genomics ProteomicsBioinformatics(GPB)is now inviting submissions for a special issue(to be published in the winter of 2015)on the topic of‘‘Biomarkers for Diseases’’.As an emerging index,disease biomarkers have demonstrated the potential application in diagnosis and prognosis.The detection of the disease indicators at molecular level,DNA,RNA     

‘Ins’ and ‘outs’ of triple therapy

Chronic oral anticoagulant treatment is obligatory in patients (class I) with mechanical heart valves and in patients with atrial fibrillation with CHADS2 score >1. When these patients undergo percutaneous coronary intervention with placement of a stent, there is also an indication for treatment with aspirin and clopidogrel. Unfortunately, triple therapy is known to increase the bleeding risk. For this group of patients, the bottom line is to find the ideal therapy in patients with indications for both chronic anticoagulation therapy and percutaneous intervention to prevent thromboembolic complications such as stent thrombosis without increasing the risk of bleeding. (Neth Heart J 2010;18:444-50.)     

QUANTITATIVE CHANGES IN GIBBERELLIN AND RNA CORRELATED WITH SENESCENCE OF THE SHOOT APEX IN THE ‘ALASKA’ PEA

Senescence of shoot apices of Pisum sativum L. ‘Alaska’ as measured by cessation of stem elongation was delayed by removal of flowers and by treatment with gibberellin A₃ and was hastened by treatment with AMO-1618 (2 isopropyl-4-dimethylamino-5-methylphenyl-1-piperi-dinecarboxylate methyl chloride). Ontogenetic changes in relative endogenous gibberellin levels and in capability of gibberellin biosynthesis in deflowered and control plants were determined indirectly by studying time-course changes in the sensitivity, as indicated by the growth response, of these plants to applied gibberellin and AMO-1618. The results of these experiments suggest that the endogenous gibberellin level varies directly with the growth rate. Analyses of total RNA and protein in shoot tips of deflowered and control plants revealed that the levels of these substances also vary directly with growth rate throughout ontogeny. It is concluded that decreases in endogenous gibberellin, RNA and protein are factors correlated with senescence of the shoot apex.     

Defining ‘Life’

There is no broadly accepted definition of life. Suggested definitions face problems, often in theform of robust counter-examples. Here we use insights fromphilosophical investigations into language to argue thatdefining `life' currently poses a dilemma analogous to thatfaced by those hoping to define `water' before the existenceof molecular theory. In the absence of an analogous theoryof the nature of living systems, interminable controversyover the definition of life is inescapable.     

扬‘课改’之帆 建‘高效’课堂

随着社会的不断发展和进步,基础教育课程改革的不断推进和深化,教师在数学教学中不仅仅要教授学生必须的基础知识和基本技能,还要培养学生的创新精神和实践能力,这样才能培养出优秀的栋梁之材。所以大多数数学教师也充分认识到了探究教学的优势,探究教学可以使学生充分发挥学生的思维和数学能力,也能使教学任务顺利并且有效的完成。     

Special Issue on‘‘Metagenomics of Marine Environments’’

<正>We are pleased to announce a special issue on‘‘Metagenomics of Marine Environments’’of the journal Genomics,ProteomicsBioinformatics(GPB),aiming to provide a platform for high-quality papers focusing on the topic and we invite submissions for this special issue(to be published in the fall of 2015).With most microbes being difficult or impossible to culture     

‘Classical’ and ‘non-classical’ reproductive steroids in fish

Summary The nature of the steroids secreted by gonads of fish differs significantly from those of the mammals. The classical teleost steroids, oestradiol, testosterone, 11-ketotestosterone and 17,20P, have been measured in a wide variety of teleosts but do not always reflect biological activities. There is increasing evidence that teleost gonads may produce a number of non-classical steroids which may play an important role in their reproductive biology. Such products include metabolites reduced at C5 to 5 or 5, at C3 to 3 or 3, or hydroxylated at 6-, 7-, or 21. Conjugation, as either glucuronides or sulphates, may contribute either to localization of action within the gonad or to production of pheromones during the immediate pre-spawning period. Although it is often possible only to measure the steroids for which assays are readily available, it is important to recognize that there may be production of steroids that are not detected by such assays, but which nevertheless play a major role in reproductive activity. In evolutionary terms, the teleost hydroxylases probably originated in the very early fishes and show parallels with their analogues in amphibians and mammals. Gene sequencing may reveal a possible common ancestor for all vertebrate 6, 7 and 11-hydroxylases.     

Reading Wacquant as both ‘lumper’ and ‘splitter’

In this short response to Loïc Wacquant's ‘Marginality, Ethnicity and Penality in the Neo-liberal City’, I outline two intellectual conversations that emerge from the author's work. The first develops out of the connections that the author draws between systems of criminal justice and welfare. The second grows out of the disassociation he urges us to see between the logics and trajectories of crime, on the one hand, and criminal justice on the other. I then briefly describe how my own work has been influenced by and contributes to these two ongoing streams of research.     

‘Cosmopolitan Baku’

Among the many points of reflection in looking back on the last 100 years in the Caucasus, a particular pride of place for some Azerbaijanis comes in the status of Baku as a cosmopolitan city: a status claimed by historians who speak of the early twentieth-century border crossings between families and trade networks across Turkey and Iran; and more recently, a status claimed by residents of the city from the Soviet 1960s and 1970s, when these diverse urban elites were at the peak of their social capital. At the same time, however, Azerbaijan had one of the lower rates of intermarriage and out-migration of all the Soviet republics. This essay therefore asks: What does cosmopolitanism mean in this context and what does it tell us about changing Caucasus landscapes?     

Structural and Narrative Reconstruction of Rural Residents’ Representations of ‘Nature’, ‘Wildlife’, and ‘Landscape’

The objective of this paper is the structural and narrative reconstruction of representations of ‘nature’, ‘wildlife’ and ‘landscape’, held by rural residents of the Dadia Forest Reserve. Data collection involved in-depth interviews. Employing a social representations’ approach, we recovered representational elements that are expected in the case of rural belief systems, such as negative dispositions towards wolves and foxes, as well as elements of an urban adherence, such as nature’s independence. Representational elements refer to visual aspects of the countryside, which seem compatible with the figurative nucleus of the rural idyll. Concerning ‘wildlife’, residents focused on vultures, which comprise the main tourist attraction of the reserve. Scientific knowledge adds to the complexity of the narrative schema, which corresponds to the representation of ‘wildlife’. Interviewees perceived the rural landscape as an interface between the natural and the human-conditioned environment. Our study shows that interviewees make no reference to environmental conservation or quality of life issues, as it could be expected according to relatively wide definitions of the term ‘environmentalism’. Environmental messages reinforced by ecotourism development seem to be recalled primarily in terms of their compatibility with the perceived economic benefit of local people. Despite ecotourism development, representational elements that diverge from a tourist version of ‘nature’, ‘wildlife’ and ‘landscape’ were not pronounced within rural belief-systems. Further interventions within the study area are needed, in order to address a variety of topics under the environmental conservation discourse and raise the environmental awareness of rural residents.     

The ‘president’s drug’

Netherlands Heart Journal -