The influence of genetic background on resistance to the cabbage aphid (Brevicoryne brassicae) in Kale (Brassica oleracea var. acephala)

Resistance to Brevicoryne brassicae has been identified in the progeny of two selected kale (B. oleracea var. acephala) plants, one from the F1 hybrid cultivar ‘Arsis RS’ and one from the landrace ‘Butzo’. These plants were crossed with susceptible B. oleracea morphotypes that have different periods to flowering. The type of susceptible plant line used had an effect on the resistance phenotypc of the progeny. Tested F2 populations derived from these crosses show that resistance is not under simple genetic control. This, in addition to variation in aphid numbers within accessions, suggests that separation of genetic components of control from environmental ‘noise’ for any accession may only be possible by the production of double haploid plant lines.     

Durations of the Photoperiod-sensitive and Photoperiod-insensitive Phases of Development to Flowering in Four Cultivars of Rice (Oryza sativa L.)

The durations of the photoperiod-sensitive and photoperiod-insensitivephases of development to panicle emergence were estimated infour contrasting indica cultivars of rice (Oryza sativa L.)in a reciprocal-transfer experiment. Plants were grown in potsin glasshouses maintained at warmer (32/26 C) or cooler (28/20C) day/night temperatures, and the durations from sowing topanicle emergence were determined for plants moved from relativelyshort (11 h) to relatively long (13.5 h) days and vice versaat various times after sowing. Panicle emergence was delayedby long days in all cultivars, but the traditional cvs Carreonand Peta were much more sensitive to photoperiod than the moderncvs IR8 and IR36 The durations of the photoperiod-insensitivepre-inductive phase (equivalent to some definitions of the basicvegetative phase) varied from 14.4 d in cv. Carreon at 32/26C to 42.0 d in cv. IR8 at 28/20 C. In all cultivars this initialphase was of a longer duration in the cool than in the warmregime. The duration of the photoperiod-insensitive post-inductivephase was also consistently greater, but usually only slightso, at cool than relatively warm temperatures; it varied from6.8 d in cv. IR8 at 32/26 C to 272 d in cv. Carreon at 28/20C. As expected, the length of the intervening photoperiod-sensitiveinductive phase was greater in long days, but the effect oftemperature on these durations was not consistent; for example,these durations were longer in warm than in cool temperaturesin cv. 1R8 but, if anything, they were slightly longer in coolthan in warm temperatures in cv. IR36. This difference is compatiblewith previous findings that cv. IR36 has a warmer optimum temperaturefor rate of progress towards panicle emergence than cv. IR8.A subsequent reciprocal-transfer experiment with cv. Peta providedestimates of the durations of the photoperiod-insensitive andphotoperiod-sensitive phases of pre-flowering development whichwere compatible with our earlier estimates. Furthermore, panicleinitiation was found to occur after about 80% of the photoperiod-sensitiveinductive phase had elapsed. We conclude that although the durationof the photoperiod-insensitive pre-inductive phase in rice isgreater than in many other annual crops, genotypic variationin this duration may well be less than was previously deduced.We also conclude that, despite common assumptions to the contrary,photoperiod-sensitivity during rice plant development does notend at panicle initiation. Oryza sativa L., rice, panicle initiation, panicle emergence, photoperiodism, temperature     

Routine audit of breast fine needle aspiration (FNA) cytology specimens and aspirator inadequate rates

Routine audit of breast fine needle aspiration (FNA) cytology specimens and aspirator inadequate rates In an attempt to improve the quality of the breast FNA specimens we instigated a continuing audit of this procedure in this hospital. All FNAs since 1990 have had the following recorded: mode of aspiration, e.g. freehand or image guided, patient presentation (screening or symptomatic), patient diagnostic category, cytological diagnosis and final histological diagnosis. Aspirator performance was assessed by means of the inadequate aspiration rate (IR) of FNAs performed on patients with a final diagnosis of cancer (FDC) and diagnostic category A patients (clinically or radiologically malignant lesions). An ongoing annual review of the performance of all the aspirators was undertaken, all of whom received individual feedback. Counselling and further training were offered where indicated by poor performance. Over the period 1990–1995 a total of 13 537 FNAs were performed by 27 aspirators. The IR on category A and FDC cases over this period was 16.0% and 18.1%. The best performance achieved by an aspirator in a calendar year was an IR of 3.6% with no inadequate specimens in either FDC or category A lesions, and the best performance over the entire period was an average IR of 11.75% and 14.25% for FDC and category A groups, respectively. The overall IR on category A patients ranged from 15.9% to 23.8% and on FDC cases from 12.2% to 21.7%. There was a significant improvement in individual junior aspirator performance when their first year was compared with their last year on the unit. In some cases a deterioration in intra-aspirator performance was observed, from an IR of 6% to 33%. The overall IR rate of the unit remained stable for FDC patients, 15.5% in 1990 compared with 15.1% in 1995. This appeared to be largely due to a high proportion of the aspirations being performed by experienced personnel with consistent IRs. However, concealed within the overall rate there were some poor performers who benefited from counselling and/or further training. These results indicate an important role for audit in identifying poor aspirators who benefit from targeted training and advice, thereby improving the quality of FNA specimens, and ultimately patient care.     

Functional morphology of synarthrial articulations in the crinoid stem

Synarthrial fulcral ridges are found in crinoid columnals from the mid-Ordovician to the present and in all four subclasses. Similar articulations did not become common in the cirri until the Mesozoic. Synarthrial stem articulations fall into two broad groups. Type I articulations have a fulcral ridge in the centre of the articular facet. In elliptical ossicles this ridge corresponds to either the long (IA) or short (IB) axis of the facet. Although both are functionally similar, Type IA ossicles are more common. Type II articulations have an excentric fulcral ridge, parallel to either the long (IIA) or short (IIB) axis of the articular facet. Type IIA articulations are found in crinoid stems capable of coiling. Type II articulations are particularly common in the cirri of articulates and are well adapted for attachment to hard and soft substrates. Columnals with Type I articulations often have divergent fulcra, giving the stem flexibility in all directions, but this feature is not seen in cirri or in coiled stems, where it would impair normal functions. Only the cirri of isocrinids and comatulids are muscular, so the movement of columns with fulcra must be passive.     

Evidence for the Presence of "Metabolic Sterols" in Pneumocystis: Identification and Initial Characterization of Pneumocystis carinii Sterols

Mixed life cycle stages of rat-derived Pneumocystis carinii were isolated from host lungs and their sterols were compared with those present in lungs from normal and immunosuppressed uninfected rats. Gas-liquid chromatography consistently detected, resolved, and quantified 9, 10, and 20 sterol components in the total nonsaponifiable neutral lipid fraction of lungs from normal rats, lungs from immunosuppressed uninfected rats, and P. carinii preparations, respectively. In all samples, cholesterol was the most abundant sterol present, comprising 97%, 93%, and 78% of total sterols in lungs from normal rats, lungs from immunosuppressed uninfected rats, and P. carinii , respectively. Tentative identifications of several rat lung and P. carinii minor sterols were made based on gas-liquid chromatogram retention times and fragmentation patterns from mass spectral analyses. Campesterol (ergost-5-en-3-ol), cholest-5-en-3-one, and β -sitosterol (stigmast-5-en-3-ol) were among the minor components present in both types of lung controls, and were also components of P. carinii sterols. In contrast to lung controls, the sterols of P. carinii were enriched in C₂₈ and C₂₉ sterols with one or two double bonds, and a hydroxyl group at C-3 (ergost-5-en-3-ol, ergost-7-en-3-ol, ergosta-dien-3-ol, stigmast-5-en-3-ol, stigmast-7-en-3-ol and stigmasta-dien-3-ol). Steryl esters of P. carinii , probably stored in cytoplasmic lipid droplets, were dominated by those present in the host lung. In separate studies. 3-hydroxy-3-methylglutaryl coenzyme A activity, a key enzyme in the regulation of sterol biosynthesis, was detected in purified P. carinii preparations and incorporation of radiolabeled squalene and mevalonate was observed. Together, these results suggest that the parasite readily takes up and incorporates host sterols, and that the organism synthesizes some of its own "metabolic sterols"     

Robust dynamics of Amazon dieback to climate change with perturbed ecosystem model parameters

Climate change science is increasingly concerned with methods for managing and integrating sources of uncertainty from emission storylines, climate model projections, and ecosystem model parameterizations. In tropical ecosystems, regional climate projections and modeled ecosystem responses vary greatly, leading to a significant source of uncertainty in global biogeochemical accounting and possible future climate feedbacks. Here, we combine an ensemble of IPCC‐AR4 climate change projections for the Amazon Basin (eight general circulation models) with alternative ecosystem parameter sets for the dynamic global vegetation model, LPJmL. We evaluate LPJmL simulations of carbon stocks and fluxes against flux tower and aboveground biomass datasets for individual sites and the entire basin. Variability in LPJmL model sensitivity to future climate change is primarily related to light and water limitations through biochemical and water‐balance‐related parameters. Temperature‐dependent parameters related to plant respiration and photosynthesis appear to be less important than vegetation dynamics (and their parameters) for determining the magnitude of ecosystem response to climate change. Variance partitioning approaches reveal that relationships between uncertainty from ecosystem dynamics and climate projections are dependent on geographic location and the targeted ecosystem process. Parameter uncertainty from the LPJmL model does not affect the trajectory of ecosystem response for a given climate change scenario and the primary source of uncertainty for Amazon ‘dieback’ results from the uncertainty among climate projections. Our approach for describing uncertainty is applicable for informing and prioritizing policy options related to mitigation and adaptation where long‐term investments are required.     

A Low-Moisture-Content Limit to Logarithmic Relations Between Seed Moisture Content and Longevity

Seeds of quinoa (Chenopodium quinoa Willd.), sunflower (Helianthusannuus L.) and linseed (Linum usitatissimum L.) showed negativelogarithmic relations between longevity and moisture contentsbetween 4.4 and 15.4, 3.2 and 13.0, and 3.2 and 15.5%, respectively,in hermetic storage at 65 °C. However, between 1.8 and 3.1,1.1 and 1.9, and 1.1 and 2.1%, respectively, longevity did notvary. The critical moisture content, below which further reductionin moisture content no longer increased longevity in hermeticstorage at 65 °C, for each species was 4.1, 2.04 and 2.7%,respectively. Quinoa, Chenopodium quinoa Willd., sunflower, Helianthus annuus L., linseed, Linum usitatissimum L., seed storage, improved viability equation, seed longevity, seed moisture content     

Flow- and substratum-mediated movement by a stream insect

1. In streams subject to frequent hydrologic disturbance, the ability of benthic invertebrates to disperse within the channel is key to understanding the mechanisms of flow refugium use and population persistence. This study focuses on crawling invertebrates, the effects on movement of abiotic factors (specifically, flow near the stream bed and bed micro‐topography) and the consequences for dispersal. 2. In a large flume, we observed individual cased caddisflies, Potamophylax latipennis, moving in fully turbulent flows over a precise replica of a water‐worked surface. From maps of movement paths, we quantified crawling behaviour and entrainment, and the influence of bed micro‐topography. We manipulated discharge and tested its effect on movement, linear displacement and areal dispersal. The highest discharge treatment was a disturbance to the caddis; the lowest discharge was not. Crawling behaviours were used to parameterise random walk models and estimate population dispersal, and to test the effects of abiotic factors on movement. 3. Bed micro‐topography influenced crawling in several ways. Caddis spent most of their time at the junctions between proud particles and the adjacent plane bed. The frequency distribution of turn angles was bimodal, with modal values approximating the angle required to travel around median‐sized particles. Larvae generally crawled downstream, but crawling direction relative to the flow was skewed by bed micro‐topography and was not directly downstream, unlike drift. 4. Caddis crawled for most of the time and discharge affected almost every aspect of their movement. As discharge increased, caddis crawled less often, more slowly and over shorter distances; they also became entrained more frequently and over greater distances. With increased discharge, caddis spent proportionately less time at the junctions between proud particles and the adjacent plane bed, and more time on the tops and sides of proud clasts. This is curious as most entrainment occurred from the tops and sides of clasts and entrainment is generally considered to be disadvantageous during disturbances. 5. Linear displacement (drift and entrainment combined) was downstream, but the relation between total displacement and discharge was complex. Total displacement decreased at intermediate discharge as crawling decreased, but increased at high discharge as entrainment and drift played a greater role in movement. 6. Within‐stream dispersal via crawling contained elements of both a correlated random walk (we observed directional persistence in turn angles) and a biased random walk (we observed downstream bias in move direction angles) and was best described as a biased correlated random walk. Dispersal was inversely related to discharge, suggesting that the ability of P. latipennis to crawl into flow refugia on the streambed is reduced at high flow.