A differential procedure for bacteriological studies useful in the fermentation industry

A synthetic differential medium was developed containing antibiotics capable of inhibiting the growth of yeast without effect on bacteria usually encountered in industrial fermentations, in particular in brewing, alcohol fermentation, and the production of baker's yeast.The differential medium and technique represent an excellent method for investigating the nature and number of viable bacteria in various fermentation materials. Results obtained on baker's yeast, distillery mashes, etc., are reported.     

Population trends of European common birds are predicted by characteristics of their climatic niche

Temperate species are projected to experience the greatest temperature increases across a range of modelled climate change scenarios, and climate warming has been linked to geographical range and population changes of individual species at such latitudes. However, beyond the multiple modelling approaches, we lack empirical evidence of contemporary climate change impacts on populations in broad taxonomic groups and at continental scales. Identifying reliable predictors of species resilience or susceptibility to climate warming is of critical importance in assessing potential risks to species, ecosystems and ecosystem services. Here we analysed long‐term trends of 110 common breeding birds across Europe (20 countries), to identify climate niche characteristics, adjusted to other environmental and life history traits, that predict large‐scale population changes accounting for phylogenetic relatedness among species. Beyond the now well‐documented decline of farmland specialists, we found that species with the lowest thermal maxima (as the mean spring and summer temperature of the hottest part of the breeding distribution in Europe) showed the sharpest declines between 1980 and 2005. Thermal maximum predicted the recent trends independently of other potential predictors. This study emphasizes the need to account for both land‐use and climate changes to assess the fate of species. Moreover, we highlight that thermal maximum appears as a reliable and simple predictor of the long‐term trends of such endothermic species facing climate change.     

The relationship between sea surface temperature and population change of Great Cormorants Phalacrocorax carbo breeding near Disko Bay,Greenland

Arctic seas have warmed and sea ice has retreated. This has resulted in range contraction and population declines in some species, but it could potentially be a boon for others. Great Cormorants Phalacrocorax carbo have a partially wettable plumage and seem poorly suited to foraging in Arctic waters. We show that rates of population change of Cormorant colonies around Disko Bay, Greenland, are positively correlated with sea surface temperature, suggesting that they may benefit from a warming Arctic. However, although Cormorant populations may increase in response to Arctic warming, the extent of expansion of their winter range may ultimately be limited by other factors, such as sensory constraints on foraging behaviour during long Arctic nights.     

Clutch size, brood size and brood emergence in the Marbled Teal Marmaronetta angustirostris in the Marismas del Guadalquivir, southwestern Spain

The first detailed study of the breeding biology of the globally threatened Marbled Teal Marmaronetta angustirostris is presented, using data from the Marismas del Guadalquivir in southwestern Spain. Complete clutches, with 9–20 eggs, were recorded from 28 April to 27 July. Excluding clutches of over 14 eggs (likely to be intraspecifically parasitized), the mean clutch size was 11.8, larger than that reported for almost all other Anatidae species. Broods hatched from May to early August (later than sympatric duck species), with a peak in mid-late June and significant annual variation in date. Brood sizes were exceptionally high, declining from a mean of 10.9 in the first week of age to 8.5 when fully feathered (at 42 days or more). Duckling mortality was concentrated in the first 2 weeks after hatching. Nine percent of broods had 15–23 ducklings, largely as a result of nest parasitism. Brood size decreased strongly with hatching date and varied significantly between years. Data from across the species' range showed that breeding occurs later at more northerly latitudes. A recent decline in the Marbled Teal in the Marismas is linked with its late breeding season. Anthropogenic changes have reduced the duration of flooding in the natural marshes of Donana National Park, which now dry out by August, before this species has completed breeding     

Influence of Chlorocholine Chloride on Grain Growth of Winter Barley (Hordeum distichon L. cv. Igri) in the Field

Green, C. F., Dawkins, T. C. K. and McDonald, H. G. 1985. Influenceof chlorocholine chloride on grain growth of winter barley (Hordeumdistichon L. cv. Igri) in the field.–J. exp. Bot. 36:1126–1133. Chlorocholine chloride was applied to winter barley either inthe Spring or Autumn. It increased grain number per unit croparea. Rates of incorporation of dry matter into the grain weredecreased, but the period of growth was extended by the treatments.Overall the final mean grain weight was reduced so that no advantagesin terms of yield resulted from the increased grain numbers. Key words: —Chlormequat, chlorocholine chloride, CCC, Hordeum distichon L., barley, grain growth, grain weight, senescence, grain yield     

Encystment of Pythium aphanidermatum Zoospores is Induced by Root Mucilage Polysaccharides, Pectin and a Monoclonal Antibody to a Surface Antigen

The infection of roots by the pathogenic Oomycete Pythium aphanidermatuminvolves interactions between the fungal zoospores and rootsurface mucilage polysaccharides. After initial recognitionat the root surface the zoospores are triggered to encyst duringwhich adhesive glycoproteins are secreted followed by a fibrillarcyst wall. In this paper a simple in vitro assay has been usedto assess the ability of a variety of macromolecules to inducezoospore encystment. Mucilage polysaccharides of the cress rootsurface trigger encystment. Whole mucilage was fractionatedby gel filtration and a fraction low in uronic acid, containing5% fucose, was shown to be more effective in triggering encystmentthan a uronic acid-rich fraction. Encystment can also be inducedby commercial pectin. The lectin Con A, and PA1, one of a rangeof monoclonal antibodies specific for zoospore surface antigens,also triggered encystment. In Western blotting experiments PA1recognizes protein epitopes of a 75 kDa surface antigen. Theresults suggest that at least one mechanism of zoospore triggeringmay involve a specific zoospore surface receptor. Key words: Pythium aphanidermatum, recognition, encystment, zoospore, mucilage, root, monoclonal antibodies, polysaccharides     

Cytogenetic evidence for a complex of species within the taxon Anopheles maculatus (Diptera: Culicidae)

Two largely independent studies of chromosomes from natural populations of Anopheles maculatus provide evidence for several genetic species within the taxon. (1) Polytene chromosome variation shows four different rearrangements of arm 2 and three rearrangements of the X chromosome. There is strong evidence for three species. Two allopatric populations represent either dramatic geographic variation for two independent inversion systems within one of the genetic species, or represent two additional species. Their species status remains unresolved by this work. (2) Heterochromatic variation occurs in both X and Y chromosomes as revealed by Giemsa-banding of mitotic chromosomes from larval brains. The distribution and association of these various sex chromosomes give further evidence of a species complex. A preliminary correlation of these two kinds of chromosomal variation is given.     

The effect of partially resistant potato clones and aldicarb on the multiplication of the potato cyst nematode Globodera pallida in field trials

Potato cultivars with different degrees of resistance to Globodera pallida (PCN) were trialled at three infested sites in 1983, 1984 and 1985. These trials were primarily intended to assess the effects of PCN damage on the yield of tubers and consequently the sites chosen had high initial population densities of G. pallida. The population density of G. pallida was determined from samples taken both pre-planting and post-harvest and results showed that there were significant differences between the clones in the nematode multiplication rates. Although actual rates of multiplication varied between sites the relative differences between clones were maintained across sites. Under the susceptible control cultivars the populations generally increased even in the presence of nematicide. The partially resistant clones gave best control, as measured by nematode multiplication, at the sites with the highest initial population densities but gave good control at all sites when treated with nematicide irrespective of initial population density. The role of partial resistance in integrated control systems and the effectiveness of nematicides against G. pallida is discussed.     

Water Use of Kiwifruit Vines and Apple Trees by the Heat-Pulse Technique

Green, S. R. and Clothier, B. E. 1988. Water use of kiwifruitvines and apple trees by the heat-pulse technique.–J.exp. Bot. 39: 115–123. The compensation heat-pulse method has been used to measuresap velocities in the stem of kiwifruit vines (Actinidia deliciosa)and apple trees (Malus sylvestris x Red Delicious). Becauseof the high flow rates typical in kiwifruit vines, we were unableto measure heat-pulse velocity using standard probe spacings.We increased the spacing between sensors with the downstreamsensor 20 mm and the upstream sensor 5-0 mm respectively fromthe heater probe. Corrections for flow blockage by the probeswere re-calculated at this new spacing for our 2-0 mm-diameterheater and teflon temperature probes following the procedureof Swanson and Whitfield (1981) Sap flux through the stem was found from heat-pulse velocitiesat four radial depths in the stem. Fluxes measured using theheat-pulse technique were compared with water uptake from appletrees and kiwifruit vines that had been cut-off at the baseand the butt placed in a container of water. Heat-pulse measurementswere also compared with known flow rates through stem-sectionsof kiwifruit vine in the laboratory. In apple the heat-pulsemeasurements agreed with independent flux measurements in excisionexperiments. In kiwifruit the independently measured fluxeswere consistently 1.6 times larger than the fluxes measuredwith the heat-pulse method. Possible reasons for this anomalousresult in kiwifruit vines are discussed