Interchange-trisomics in barley

Observations on morphology, sterility and cytology of some interchangetrisomics obtained from the progeny of radiation induced interchangeheterozygotes in a 6-rowed barley (Hordeum vulgare L.) var. K₁₂ are described. The different interchange trisomics show distinct phenotypic expression and have been classified as bushy, slender, robust, semi-erect and pseudonormal on the basis of their gross morphology, leaf characteristics, awn and spike lengths. All interchange trisomics show pollen and ovule sterility which varies between plants. Meiotic behaviour is described. The five different interchange trisomics appear to have different extra chromosomes.     

Anaerobic dechlorination and degradation of hexachlorocyclohexane isomers by anaerobic and facultative anaerobic bacteria

Screening studies with strict and facultative anaerobic bacteria showed that Clostridium app. and several other representatives of Bacillaceae and Enterobacteriaceae actively degraded -hexachlorocyclohexane (-HCH) under anaerobic conditions. Representatives of Lactobacillaceae and Propronibacterium were inactive. With ³⁶Cl-labelled -HCH a nearly complete dechlorination was shown to occur in 4–6 days by Clostridium butyricum, C. pasteurianum and Citrobacter freundii, while other facultative anaerobic species were less active.Aerobically grown facultative anaerobes also dechlorinated actively -HCH during subsequent anaerobic incubation with glucose, pyruvate or formate as substrates. The -, - and -HCH isomers were also, but more slowly, dechlorinated (>>-HCH). All species active in anaerobic degradation of -HCH formed -tetrachlorocyclohexene (TCH) as the main intermediate metabolite and no -pentachlorocyclohexene (PCH) or other isomers of TCH or PCH have been found. Small amounts of tri- and tetrachlorinated benzenes have been found too. The mechanism of dechlorination is discussed.Non-Common Abbreviations Used -HCH -hexachlorocyclohexane - -TCH -2,3,4,5-tetrachlorocyclohexene - -PCH -1,2,3,4,5-pentachlorocyclohexene - GLC gas liquid chromatography     

Characterisation of the cDNA clones of two β-tubulin genes and their expression in the potato plant (Solanum tuberosum L.)

The cDNA clones of two potato -tubulin genes were isolated from a tuberising stolon tip library. Analysis of 20 positive clones showed that they represented one or another of two different but very similar -tubulin genes, designated TUBST1 and TUBST2. The expression pattern of -tubulin genes in the potato plant was investigated by RNA blot analysis and by RT-PCR. Southern analysis of potato genomic DNA with coding and non-coding -tubulin probes revealed that there are multiple -tubulin genes in the potato genome and that there is likely to be considerable divergence in the 3 non-coding sequences. Phylogenetic analysis of plant -tubulin genes is described.     

Virulence as a consequence of genome instability of a novel temperate bacteriophage, ΦRsG1, of Rhodobacter sphaeroides Y

A novel temperate bacteriophage, designated RsG1, was isolated from Rhodobacter sphaeroides Y (previously designated Rhodopseudomonas sphaeroides) following exposure to mitomycin C. The phage morphology, as revealed from electron microscopy, showed a hexagonal head (90 by 46.5 nm) connected with a tail (116 by 9.4 nm), to which a collar was proximally attached. A morphologically similar phage was also produced by spontaneous lysis of the cells. While RsG1 did not grow on any other bacterial strain tested, spontaneously produced phage particles propagated (and formed plaques) on R. sphaeroides Y still carrying RsG1 in the prophage state. The genome of RsG1 consisted of double stranded linear DNA with cohesive ends and a GC-content of 71.8 mol%. The DNA molecules formed circles in vitro with a mean contour length of 17.18±0.4 m, which corresponds to a size of 49 kbase pairs (kb). On the other hand, DNA extracted from the virulent phage particles was heterogeneous and consisted of two DNA species of different size, occurring in a ratio of about 1:1. These molecules also circularized having contour lengths of 17.18±0.4 m and 14.02±0.41 m corresponding to 49 and 40 kb, respectively. Restriction digest analysis of the two DNA species and DNA from RsG1 indicated that they are similar, and allowed the indentification of an 11.5 kb EcoRI fragment that carries the cohesive ends. Because DNA from RsG1 and the 49 kb DNA of the virulent phage particles were indistinguishable with the criteria applied, it is suggested that phage particles containing the 40 kb DNA represent the virulent type of phage, termed RsG1.1.     

Formation of the imidazolides of dinucleotides under potentially prebiotic conditions

Summary Imidazolides of dinucleotides such as ImpApA can be formed from the corresponding dinucleotides in a two-stage process, which gives up to 15% yields under potentially prebiotic conditions. First a solution of the dinucleotide and sodium trimetaphosphate is dried out at constant temperature and humidity. This produces polyphosphates such as pnApA in excellent yield (80%). The products are dissolved in water, imidazole is added, and the solution is dried out again. This yields the 5-phosphorimidazolides.Abbreviations P₃! trimetaphosphate - A adenosine - U uridine - EDTA ethylenediaminetetraacetic acid - Ap adenosine 2(3)-phosphate - Ap! adenosine cyclic 2:3-phosphate - pA adenosine 5-phosphate - pA²p adenosine 2, 5-diphosphate - pA³p adenosine 3, 5-diphosphate - pAp! 5-phospho-adenosine cyclic 2:3-phosphate - ATP adenosine 5-triphosphate - ImpA adenosine 5-phosphorimidazolide - A²pA adenylyl-[25]-adenosine - A³pA adenylyl-[35]-adenosine - A²pU adenylyl-[25]-uridine - A³pU adenylyl-[35]-uridine - pA²pA 5-phosphoadenylyl-[25]-adenosine - pA³pA 5-phospho-adenylyl-[35]-adenosine - pA²pU 5-phospho-adenylyl-[25]-uridine - pA³pU 5-phospho-adenylyl-[35]-uridine - pApN (N= A, U) 5-phosphate of a dinucleoside phosphate - p_nApN (N = A, U; n = 2, 3, 4.) 5-polyphosphate of a dinucleoside phosphate - ImpA²pA imidazolide of pA²pA - ImpA³pA imidazolide of pA³pA - ImpA²pU imidazolide of pA²pU - ImpA³pU imidazolide of pA³pU - ImpApN imidazolide of pApN     

Interactions of γ-L-glutamyltaurine with excitatory aminoacidergic neurotransmission

The in vitro effects of -L-glutamyltaurine on different stages of excitatory aminoacidergic neurotransmission were tested with -D-glutamyltaurine as reference. -L-Glutamyltaurine enhanced the K⁺-stimulated release of [³H]glutamate from cerebral cortical slices (25% at 0.1 mM) and slightly inhibited the uptake by crude brain synaptosomal preparations (about 10% at 1 mM). -L-Glutamyltaurine was also a weak displacer of glutamate and its agonists from their binding sites in brain synaptic membrane preparations, being, however, less selective to quisqualate (QA) sites than -D-glutamyltaurine. The basal influx of Ca²⁺ into cultured cerebellar granular cells was not affected by 1 mM -L-glutamyltaurine, but the glutamate- and its agonist-activated influx was significantly inhibited in low-Mg²⁺ (0.1 mM) and Mg²⁺-free media. The glutamate-evoked increase in free intracellular Ca²⁺ and the kainate-activated formation of cGMP in cerebellar slices were both markedly inhibited by 0.1 mM -L-giutamyltaurine. We propose that -L-glutamyltaurine may act as endogenous modulator in excitatory aminoacidergic neurotransmission.     

Effect of orchard and postharvest application of daminozide on ethylene synthesis by apple fruit

The effects of daminozide (butanedioic acid-2,2-dimethylhydrazide) on ethylene synthesis by apple fruits were investigated. The objective was to determine the effects of postharvest applications as compared to the standard application of diaminozide in the orchard. Immersion in a solution containing 4.25 g L^–1 active ingredient for 5 min delayed the rise in ethylene production in individual Cox apples at 15°C by about 2 days, whereas orchard application of 0.85 g L^–1 caused delays of about 3 days. Both modes of application depressed the maximal rate of ethylene production attained by ripe apples by about 30%. Daminozide did not affect the stimulation of respiration by ethylene treatment of Gloster apples, but it delayed the increase in ethylene synthesis. Daminozide applied immediately after harvest delayed the rise in ethylene synthesis in Golden Delicious held at 15°C, but it was less effective when applied 48 h after harvest or when apples were held at 5°C. Exposure to 1–2 l L^–1 ethylene for 48 h was less effective in promoting the rise in ethylene in daminozidetreated Cox and Gloster apples than in untreated fruit. High (100–1000 l L^–1) concentrations of ethylene more or less overcame the daminozide effect. Apples absorbed about 40% of surface-applied [¹⁴C]daminozide in 48 h, but more than 90% of the radioactivity in the fruit was recovered from the peel and outer 1 cm of the cortex. Daminozide was partly converted to carbon dioxide and other metabolites.     

Niche dimensions of New England cottontails in relation to habitat patch size

We examined physical condition, niche dimensions, and survival of New England cottontails (Sylvilagus transitionalis) that occupied 21 habitat patches of different sizes during winter. Rabbits on small patches (2.5 ha) were predominantly males, and both sexes had lower body mass than individuals on large patches (5.0 ha). Niche indices (, where ranges from 0 to 1. and values approaching 1 indicate generalized resource use) of habitat use revealed that rabbits on small patches used a greater variety of microhabitats (based on understory stem density: _s, and proximity to cover: _c) than rabbits occupying large patches (_s=0.65, _c=0.66). Rabbits on small patches also consumed low quality forage more often and fed at sites farther from escape cover than rabbits on large patches. There were no significant correlations between rabbit densities and niche dimensions. Niche expansion was not a result of compertitive release or relaxation of predator pressure. Rabbits on small patches apparently modified their niche dimensions in response to resource limitations. This response included occupying sites with limited understory cover that apparently resulted in rabbits on small patches having a lower survival rate (0.35) than rabbits on large patches (0.69) during a 10-week monitoring period. Skewed sex ratios and low survival rates among rabbits on small patches suggest that these habitats act as sinks to dispersing, juveniles from large (source) patches. As a result, local populations of New England cottontails may become vulnerable to extinction if larte patches of habitat are not maintained.     

On the relationship between chlorophyll fluorescence quenching and the quantum yield of electron transport in isolated thylakoids

The relationship between the empirical fluorescence index F/Fm and the quantum yield of linear electron flow, ^s, was investigated in isolated spinach thylakoids. Conditions were optimised for reliable determination of F/Fm and ^s with methyl viologen or ferricyanide as electron acceptors under coupled and uncoupled conditions. Ascorbate in combination with methyl viologen was found to stimulate light-induced O₂-uptake which is not reflected in F/Fm and interpreted to reflect superoxide reduction by ascorbate. In the absence of ascorbate, the plot of F/Fm vs. ^s was mostly linear, except for the range of high quantum yields, i.e. at rather low photon flux densities. With ferricyanide as acceptor, use of relatively low concentrations (0.1–0.3 mM) was essential for correct Fm-determinations, particularly under uncoupled conditions. Under coupled and uncoupled conditions the same basic relationship between F/Fm and ^s was observed, irrespective of ^s being decreased by increasing light intensity or by DCMU-addition. The plots obtained with methyl viologen and ferricyanide as acceptors were almost identical and similar to corresponding plots reported previously by other researchers for intact leaves. It is concluded that the index F/Fm can be used with isolated chloroplasts for characterisation of such types of electron flow which are difficult to assess otherwise, as e.g. O₂ dependent flux. The origin of the non-linear part of the relationship is discussed. An involvement of inactive PS II centers with separate units and inefficient Q_A-Q_B electron transfer is considered likely.Abbreviations AsA - ascorbate - DCMU - 3-(3,4-dichlorophenyl)-1,1-dimethylurea - MDA - monodehydroascorbate - MV - methyl viologen - PAR - photosynthetically active radiation - SOD - superoxide dismutase This paper is dedicated to David Walker who after 40 years in the field of photosynthesis is now retiring from his duties at Sheffield University.     

The North Sea: source or sink for nitrogen and phosphorus to the Atlantic Ocean?

Annual nitrogen and phosphorus budgets for the whole North Sea taking into account the most recent data available were established. The area considered has a total surface of approximately 700,000km² and corresponds to the definition by OSPARCOM (Oslo and Paris Commission) with the exclusion of the Skagerrak and Kattegat areas. Input and output fluxes were determined at the marine, atmospheric, sediment and continental boundaries, and riverine inputs based on river flows and nutrient concentrations at the river–estuary interface were corrected for possible estuarine retention. The results showed that the North Sea is an extremely complex system subjected to large inter-annual variability of marine water circulation and freshwater land run-off. Consequently, resulting total N (TN) and P (TP) fluxes are extremely variable from 1 year to another and this has an important influence on the budget of these elements. Total inputs to the North Sea are 8870±4860kTNyear^–1 and 494±279kTPyear^–1. Denitrification is responsible for the loss of 23±7% of the TN inputs while sediment burial is responsible for the retention of only of 2±2% of the TP input. For TN, due to the large variability on marine and estuarine fluxes, and to the uncertainty related to the denitrification rate, it was concluded that the North Sea could either be a source (1930kTNyear^–1) or a sink (1700kTNyear^–1) for the waters of the North Atlantic Ocean. For TP it was concluded that the North Sea is mostly a source (–4 to 52kTPyear^–1) for the waters of the North Atlantic Ocean.     

Osmotic measurements on stomatal cells ofCommelina communis L.

Summary Observations of aperture changes as sucrose is added to the solution bathing epidermal strips ofCommelina communis L. allow calculation of the osmotic changes required to open or close the stomatal pore, for comparison with changes in potassium content. With isolated guard cells, in strips in which all cells other than guard cells have been killed, the internal osmotic changes required are 83 mosmol kg^–1 m^–1 below 10m aperture, 129 mosmol kg^–1 m^–1 in the range 10–15 m, and 180 mosmol kg^–1 m^–1 above 15 m. For opening against subsidiary cell turgor in addition to guard cell turgor, in intact strips with live subsidiary and epidermal cells, these figures should each be increased by about 33 mosmol kg^–1 m^–1. A change in subsidiary cell turgor is magnified in its effects on the water relations of the guard cell by a factor greater than 3.7 for equal changes in the water potential of the two cells, or greater than 4.7 at constant volume of the guard cell.     

Interpretation of metameric architecture in dominant shrubs of the Chilean matorral

Summary The seasonal progression of phenophases in 21 shrub species of the Chilean matorral was analyzed. Five modules or basic units that are responsible for the aboveground architecture of the plants were characterized. These modules appear to be organized in seven different spatial arrangements. In drought-deciduous species a module type with an absolute short shoot with limited apical growth, leafy or spiny, predominated. In evergreen species long shoot and temporal leafy short shoot module types were more frequent. The spatial arrangement of morphologically different modules and the temporal sequence of their formation allow a dynamic interpretation of the modular architecture of the plants.     

The relationships between the structure of paddy levees and the plant species diversity in cultural landscapes on the west side of Lake Biwa,Shiga, Japan

Paddy levees form networks of narrow linear habitats and play various roles in cultural landscapes. Traditional landscapes on the west side of Lake Biwa consist of paddy field terraces and both stone and soil levees that have been maintained by paddy field management using local resources. Paddy levees in this study site are principally classified into five different types. Our study points out how differences in paddy levee structure as well as in management practices influence the plant species. Seventeen paddy levee transects were split into four habitat types based on their species components by TWINSPAN. Spatial characteristics and physical structures of paddy levees depended on natural conditions and human activities. The species–area curves of each levee type showed a clear distinction: the soil, stone and abandoned curves were steep, while the concrete and consolidated ones were gentle. The vegetation on consolidated levees was utterly different from the vegetation on traditional levee types from the aspect of species richness and species components. Soil type levees contained various woody plant species and included more diverse and indigenous plant species than abandoned type levees.     

Plantlet regeneration from mesophyll protoplasts ofBetula platyphylla var.japonica

Summary InBetula platyphylla var.japonica, colonies were induced efficiently from mesophyll protoplasts cultured in half strength MS (1/2MS) liquid medium containing 0.6 M mannitol, 0.09M sucrose and 1 M 4-PU and 1 M NAA at a cell density of 5 × 10⁴/ml. The colonies grew actively and developed into callus after 3 months of culture.Roots differentiated from the protoplast-derived white calluses cultured on the 1 /2MS solid media supplemented with 0.1–1 M 4-PU and 1 M NAA, and 10 M zeatin with no supplementation of NAA. Furthermore, the protoplast-derived green callus differentiated shoots with 1/2MS solid medium containing 1 M 4-PU or 10 M zeatin with no supplementation of NAA. When shoots obtained were cultured on the cytokinin-free MS solid medium with 2.5 M IBA and 0.1 M NAA, they rooted and developed into plantlets after one month of culture.The phenylurea-type cytokinin, 4-PU, was effective for plantlet regeneration from the mesophyll protoplasts ofB. platyphylla var.japonica. This suggests that there is potential for the use of 4-PU in the culture of protoplasts in many forest tree species.Abbreviations BAP 6-benzylaminopurine - 2,4-D 2,4-dichlorophenoxyacetic acid - FDA fluorescein diacetate - IBA indole-3-butyric acid - 2ip N ⁶-(2-isopentenyl)-adenine - NAA 1-naphthaleneacetic acid - 4-PU N-(2-chloro-4-pyridyl)-N–phenylurea - TDZ thidiazuron     

Pompholyx of the nail organ and the true onychomycosis

Pompholyx is one clinical form of the endoparasitic-hematogenous skin eruptions. It is characterized by sago-grain-like, deeply embedded blisters or pustules within the normal, primarily non-inflamed skin, localized to the palms, soles, fingers, toes and interdigital webs, and in the nail organ. The blisters may be located in the nail wall causing paronychia, and/or beneath the nail plate causing onychia. The discussion of the etiology and pathogenesis of the pompholyx of the nail organ is inseparable from pompholyx at other sites (e.g. palms and soles), since they are identical. Hence, the term pompholyx should replace such misleading terms as infectious eczematoid dermatitis, id eruption, of the hand and/or feet, dermato- or epidermophytosis, dyshidrosis, and the vernacular athlete's foot. Even though hyphomycetes (true pathogens and common molds) of many sorts may be detected in the roof of the blisters, particularly on the feet, and scrapings of detritus from the nails, they have no role in the etiology or pathogenesis of this condition. Due to an universal infection immunity pompholyx is not infectious or transmissible. True onychomycosis is clinically and pathogenetically an entirely different condition. The purpose of this paper is to clarify the fundamental differences in etiology and pathogenesis between the two conditions.     

Between fact and technique: The beginnings of hybridoma technology

Conclusion At several places in this paper we have made use of a well-known rhetorical device: an argument was made; a character —dubbed fictional reader — was then evoked who voiced some objections against that particular argument; and finally, we answered those objections, thus bringing to a close, at least temporarily, our argument. The use of this device raises a question: How is the presence of the fictional reader to be understood? Is it a mere rhetorical tool, or does this character designate some particular target? For instance, depending on the context, it could be seen as aimed at different straw men: traditionally minded sociologists, Whiggish historians, well-intentioned philosophers of science. Actually, none of these characters is behind the fictional reader. Rather, it refers, potentially, to any of the scientific actors (Milstein, Schwaber, Koprowski, Cohn, and so on) who inhabit our set of narratives. In other words, the fictional reader is an icon for the native reader/writer who simultaneously produces and questions the products of that particular literary activity known as scientific texts, by explicitly and implicitly raising the issue of the distinction between fact and technique.By following actors in their disputes about the novelty of K & M's contribution, it became apparent that it is not exactly clear which of the different elements of hybridoma technology should be regarded as novel. Was it the use of the P3 myeloma line? Was it the theoretical framework related to the notion of allelic exclusion? Was it ...? In each and every case, arguments can be made for or against the existence of a certain continuity or discontinuity with previous work. And in each case, the determination of novelty, as translated through the continuity/discontinuity issue, appeared to be hanging on the previous attribution of an epistemological status to the object that had allegedly been discovered: was it a fact or a technique?If one focuses on the relatively narrow network of immunogenetics, it could be argued that within that particular evidential context a series of facts had been established which, when transferred to other fields, such as the virological research being pursued in Koprowski's institute, were translated into a technique. However, as we have seen, even from an immunogenetic point of view the production of monoclonal antibodies can be viewed as being simultaneously a fact and a technique to establish that fact. Not only, as he himself noted,¹³⁹ was Milstein not seeking to develop a technique for the production of monoclonal antibodies when the original experiments were carried out, but the significance later imputed to those experiments was not immediately attributed to them. The paper was seen as one among other papers that used cell fusion techniques to dissect the genetic control of antibody diversity. Distinctions that now appear crucial (e.g.: were the fusion partners two myelomas or a myeloma and a spleen cell?) were easily overlooked. At some point, around 1977, the production of monoclonal antibodies became a goal in itself, no longer linked to the initial immunogenetic network. The transformation of [MILSTEIN 75] into the foundational event of hybridoma technology was thus achieved. This transformation did not flow naturally from the original experiments. Rather, it involved specific investments which mobilized the activity of a large number of other scientific and industrial actors.¹⁴⁰ A tentative generalization can be deduced from our case study. The dichotomy between fact and technique that underlines much of contemporary science studies seem to be fundamentally misconceived, insofar as the determination of what counts as a fact and what counts as a technique is not possible on a priori grounds. Historians and sociologists of science are confronted with a field of heterogeneous interventions where particular pieces of work are constituted as discrete entities and simultaneously attributed a technical or a factual identity. Novelty and innovation are precisely the result of such polymorphic attributional processes.     

Recruitment Behavior in the Ant Genus Polyrhachis (Hymenoptera, Formicidae)

We present a detailed behavioral analysis of the signals involved in recruitment of 11 syntopic Polyrhachis species from West Malaysia. We found a considerable variety of recruitment techniques, including social carrying behavior, tandem running, group recruitment, and a technique which we call leader-independent trail communication. The latter mode superficially resembles chemical mass communication (sensu Wilson, 1962). All these recruitment techniques involve mechanical invitation behavior inside the nest, comprising back-and-forth jerking or pulling movement often combined with a sideways waggling. However, not in all cases of leader-independent trail communication is a mechanical invitation behavior obligatory. The trail pheromone of all investigated Polyrhachis species originates from the hindgut. Only in the tandem running P. proxima do additional secretions from the poison gland appear to be involved in tandem calling.     

Secretion of either of a pair of immunoglobulins,IgM or IgX,in somatic hybrid cells derived by fusion of a B-cell lymphoma cell line carrying both immunoglobulin isotypes

The I.29 cell line is a nonsecreting B-cell leukemia which bears two different immunoglobulin isotypes on its surface, IgM and IgX. The I.29 cells were hybridized with nonsecreting myeloma cells giving rise to dozens of immunoglobulin secreting hybridomas. These fall into three groups differing in the class of immunoglobulin they secrete. Cells of the first group secrete pentameric IgM (, ), those of the second group secrete an unknown immunoglobulin, IgX, which may constitute an allotype of IgA, and those of the third group produce light chains only. The two complete immunoglobulins, IgM and IgX, have the same idiotype, as revealed by serological cross-reactivity of an exhaustively absorbed rabbit anti-idiotype serum.The molecular sizes of the heavy chains of the secreted IgM and IgX are slightly smaller than the and chains, respectively, which are derived from the surface of normal B cells as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.Abbreviations used in this paper Ig immunoglobulin - NMS normal mouse serum - NaDodSO₄ sodium dodecyl sulfate - PAGE polyacrylamide gel electrophoresis - 2ME 2-mercaptoethanol - BPB bromophenol blue - NP40 nonidet P40 This particular immunoglobulin heavy chain has not been fully characterized. It is neither , , nor but is related to, although not identical with, . Because this immunoglobulin has unique properties, it is referred to as IgX.     

An Interactive Model of Human and Companion Animal Dynamics: The Ecology and Economics of Dog Overpopulation and the Human Costs of Addressing the Problem

Companion animal overpopulation is a problem of human creation with significant human costs that can only be addressed through human action. A model was constructed to understand the dynamics of canine overpopulation and the effectiveness of various policy options for reducing euthanasia. The model includes economic and ecological factors in human and dog populations. According to the model, a no-kill society is an achievable goal at an acceptable human cost. Spay/neuter programs were generally found to be the most effective, with increasing adoptions also being an effective option. However, spay/neuter policies need to be evaluated over a very long time horizon since full impact may not be achieved for 30 years or more. Spay/neuter efforts can have a large impact even if they only effect a small portion of the human population. Adoption and spay/neuter programs were found to work well in combination, and to continue being effective as society approaches no-kill dynamics.