Complementarity of particles and pits in freeze-fractured hepatic and cardiac gap junctions

Summary Particles and pits of freeze-fractured gap junctions are considered as complementary structures despite the frequent observations of more regular and closer spacings of pits, ascribed to plastic deformation of particle arrays. Recently, however, the noncomplementarity of pits and particles in Purkinje fibers has been reported. To ascertain the relationship between both structures, gap junctions from fixed, cryoprotected liver and myocardium were investigated using spacing and density measurements and complementary replicas.In hepatocyte gap junctions, the center-to-center distances (mean±sd) among pits, 9.57±1.49 nm, and particles, 9.70±1.77 nm, are not significantly different. Density determinations yielded a slightly higher value for the pits, (11,510±830)/m², than for the particles, (11,230±950)/m². In the myocardium, the spacing of the regularly arrayed pits, 9.55±1.33 nm barely exceeds the value of 9.44±1.62 nm for the particles, which show some clustering. However, the packing density for the pits, (10,090±740)/m², appears a little higher than that of the particles (9,890±920)/m². As density and spacing measurements provided no decisive answers, the positions of individual pits and particles of complementary junctional faces were recorded on transparent sheets and compared. In this fashion, a one-to-one correspondence between particles and pits could be established, while small discrepancies may be attributed to plastic deformation. Moreover, the collinearity of pits and particles may be suggested by the observation of a platinum grain in the center of many pits.     

杂交水稻及三系在发育过程中的酯酶同工酶比较研究

本文报道了利用聚丙烯酰胺凝胶电泳技术,测定杂交水稻及三系亲本共50个组合的萌动胚、芽,不同发育时期的叶片、根、雄蕊等12个组织或器官的酯酶同工酶的结果。根据所测结果,可把杂交水稻的酯酶同工酶酶谱分为5种类型:互补型、偏父型、偏母型、同型和“杂种”酶谱。强优势组合以互补型酶谱居多,弱优势组合都是同型酶谱,“杂种”酶谱仅见于V优64的幼穗分化期叶片和V优63、汕优63的三叶期叶片中。不同器官的互补酶谱都可作为预测杂种比势,鉴定杂交稻种子的纯度和真实性以及选配新杂交组合的一个手段或依据,但以对萌动胚或幼芽的测定更有实践意义。     

The 5′ untranslated region of Arabidopsis thaliana calmodulin cDNA is an independent cDNA containing an open reading frame

A cDNA clone, pAUK1, with an open reading frame (ORF) coding for a hypothetical 164-amino-acid protein was isolated from an Arabidopsis thaliana (L.) Heynh cDNA library. The clone was attached, tail to tail, to the 3′ end of A. thaliana hexokinase cDNA. An almost identical sequence had been previously described as the 5′ untranslated region (5′ UTR) of A. thaliana calmodulin cDNA (ACaM-2). Sequence comparison with three additional A. thaliana truncated cDNA clones which appear in a database (GenBank) supports the conclusion that pAUKl is identical to the 5′ UTR of ACaM-2 and that the 5′ UTR of ACaM-2 is an independent cDNA artificially linked to A. thaliana calmodulin cDNA.     

COMPLEMENTARY SEX DETERMINATION IN HYMENOPTERAN PARASITOIDS AND ITS IMPLICATIONS FOR BIOLOGICAL CONTROL

Abstract In haplodiploid Hymenoptera, unfertilized eggs produce haploid males while fertilized eggs lead to diploid females under most circumstances. Diploid males can also be produced from fertilization under a system of sex determination known as complementary sex determination (CSD). Under single-locus CSD, sex is determined by multiple alleles at a single sex locus. Individuals heterozygous at the sex locus are female while hemizygous and homozygous individuals develop as haploid and diploid males, respectively. In multiple-locus CSD, two or more loci, each with two or more alleles, determine sex. Diploid individuals are female if one or more sex loci are heterozygous, while a diploid is male only if homozygous at all sex loci. Diploid males are known to occur in 43 hymenopteran species and single-locus CSD has been demonstrated in 22 of these species. Diploid males are either developmentally inviable or sterile, so their production constitutes a genetic load. Because diploid male production is more likely under inbreeding, CSD is a form of inbreeding depression. It is crucial to preserve the diversity of sex alleles and reduce the loss of genetic variation in biological control. In the parasitoid species with single-locus CSD, certain precautionary procedures can prevent negative effects of single-locus CSD on biological control.     

Calluna and its associated species: Some aspects of co-existence in communities

Summary Using heath communities (dominated byCalluna vulgaris) as an example, an attempt is made to identify those characteristics of other species wiich enable them to co-exist with the dominant. In the course of its life-span,Calluna passes through a series of growth phases (pioneer, building, mature, degenerate) during which there are marked changes in the condition affecting associated species. These display a variety of ‘complementary strategies’ which enable them to co-exist withCalluna during a part, or the whole, of the sequence. Changes with time in the flora of even-aged stands ofCalluna, produced as a result of management by burning, are accounted for in similar terms. It is also shown that invasion of heath communities by tree species (e.g.Betula spp.,Pinus sylvestris), which may eventually eliminateCalluna, is related to the sequence of growth-phases. Contribution to the Symposium on plant species and plant communities, held at Nijmegen, 11–12 November 1976, on the occasion of the 60th birthday of Professor Victor Westhoff-to whom the author conveys the good wishes of Scottish botanists and conservationists, and particularly those of the University of Aberdeen. Nomenclature follows Clapham, Tutin & Warburg (1962) for vascular plants, Watson (1968) for bryophytes, and Duncan (1970) for lichens. Following common practiceCalluna vulgaris is referred to simply asCalluna. Grateful acknowledgement is made to several present and former research students who have kindly permitted the use of their data: particularly P. Barclay-Estrup, Edith M. French, Gong Wooi Khoon, C.J. Legg, Evelyn W. Paterson, S.D. Ward. I am especially grateful to C.J. Legg for valuable discussions on the subject of this paper.     

Assessment of the potential iridology for diagnosing kidney disease using wavelet analysis and neural networks

Alternative or complementary medicine emphasizes therapies that are claimed to improve quality of life, prevent disease, and address conditions that conventional medicine has limited success in curing. There are many techniques which are prevalent in many countries and these can cause harm if not scientifically evaluated. The objective of this paper is to validate the use of iridology to diagnose kidney abnormalities. Two subject groups were evaluated: one was 168 subjects free from kidney disease and the other was 172 subjects with chronic renal failure. The procedure to acquire, process and classify the iris images was designed in such a way that avoids any dependency on the iridologists by using wavelet analysis and Adaptive Neuro-Fuzzy Inference System. The results show a correct classification for both subjects with kidney problems and normal subjects of 82% and 93%, respectively. The proposed technique conducted on a systemic disease with ocular manifestations showed encouraging results. However, it is necessary to perform extensive studies with diseases that do not have ocular manifestations according to conventional medicine in order to validate iridology as a valid scientific technique.     

Psychological and physiological effect in humans of touching plant foliage - using the semantic differential method and cerebral activity as indicators

Background

Numerous studies have reported on the healing powers of plants and nature, but there have not been so many instances of experimental research. In particular, there are very few psychological and physiological studies using tactile stimuli. This study examines the psychological and physiological effects of touching plant foliage by using an evaluation profile of the subjects’ impressions and investigating cerebral blood flow.

Methods

The subjects were 14 young Japanese men aged from 21 to 27 years (mean ± standard deviation: 23.6 ± 2.4). With their eyes closed, the subjects touched four different tactile samples including a leaf of natural pothos (Epipremnum aureum). The physiological indices were compared before and after each stimulus. Psychological indices were obtained using a ‘semantic differential’ method.

Results

The fabric stimulus gave people ‘soft’ and ‘rough’ impressions, ‘kind’, ‘peaceful’ and ‘pleasant’ feelings psychologically, and a sense of physiological calm. On the other hand, the metal stimulus gave people ‘cold’, ‘smooth’ and ‘hard’ impressions and an image of something ‘artificial’. The metal stimulus caused a stress response in human cerebral blood flow although its evaluation in terms of ‘pleasant or unpleasant’ was neutral. There were no remarkable differences between the stimuli of natural and artificial pothos compared with other types of stimulus psychologically. However, only the natural pothos stimulus showed a sense of physiological calm in the same appearance as the fabric stimulus.

Conclusions

This study shows that people experience an unconscious calming reaction to touching a plant. It is to be concluded that plants are an indispensable element of the human environment.     

Fungal associates of the tree-killing bark beetle,Ips typographus,vary in virulence,ability to degrade conifer phenolics and influence bark beetle tunneling behavior

The bark beetle Ips typographus carries numerous fungi that could be assisting the beetle in colonizing live Norway spruce (Picea abies) trees. Phenolic defenses in spruce phloem are degraded by the beetle's major tree-killing fungus Endoconidiophora polonica, but it is unknown if other beetle associates can also catabolize these compounds. We compared the ability of five fungi commonly associated with I. typographus to degrade phenolic compounds in Norway spruce phloem. Grosmannia penicillata and Grosmannia europhioides were able to degrade stilbenes and flavonoids faster than E. polonica and grow on minimal growth medium with spruce bark constituents as the only nutrients. Furthermore, beetles avoided medium amended with phenolics but marginally preferred medium colonized by fungi. Taken together our results show that different bark beetle-associated fungi have complementary roles in degrading host metabolites and thus might improve this insect's persistence in well defended host tissues.     

Analysis of bilateral inverse symmetry in whole bacterial chromosomes

The positions of the 64 DNA tri-nucleotides (triplets) along the Borrelia burgdorferi chromosome were determined and cumulative position plots (CPP) were obtained. Analysis of CPP for complementary triplets revealed close correlations in complementary triplet frequencies (CTF) between opposing leading and lagging strands. Such bilateral inverse symmetry (BIS) applied also to complementary mono- and di-nucleotides and to some >3 n-tuples. At the level of individual bases BIS explains Chargaff's second parity rule for whole bacterial chromosomes. Using shuffled control sequences we show that single-base BIS was not the source of higher-order BIS. Analysis of CTF in 45 other chromosomes suggests that BIS is a general property of eubacteria. BIS at the various levels may be due to the very similar numbers of codons used in chromosomal halves. Evolutionarily, BIS could have resulted from asymmetric substitution of bases combined with genetic rearrangements. However, the provocative theoretical alternative of whole-genome inverse duplication is here considered.     

Two into One Won’t Go: Conceptual, Clinical, Ethical and Legal Impedimenta to the Convergence of CAM and Orthodox Medicine

The convergence of complementary and alternative medicine (CAM) and evidence-based medicine (EBM) is a prominent feature of healthcare in western countries, but it is currently undertheorised, and its implications have been insufficiently considered. Two models of convergence are described – the totally integrated evidence-based model (TI) and the multicultural-pluralistic model (MP). Both models are being incorporated into general medical practice. Against the background of the reasons for the increasing utilisation of CAM by the public and by general practitioners, TI-convergence is supported and MP-convergence is rejected. MP-convergence is epistemologically and clinically incoherent, and it cannot be regulated. It is also inconsistent with developments in the legal determination of the standard of care for both diagnosis/treatment and disclosure. These claims concerning MP-convergence are justified by the fact that science is not a member of the group of perspectives or world-views which postmodernism treats as equally valid, and this is especially important for healthcare.