A possible virus cryptic in carnation

Small isometric virus-like particles were found in low concentration in apparently healthy carnations of the Mediterranean, miniature and Chinese type but not in eleven Sim cultivars tested. Most carnations containing these particles were from Italy but some were from France and the USA. The particles were not transmitted by grafting or by mechanical inoculation but were seed-transmitted to a large proportion of seedlings. Antisera to partially purified particles were obtained. The particles did not react with antisera to twenty-eight isometric plant viruses or virus-like particles but were serologically related to similar particles found in carnations in England, Holland and Israel. When negatively stained, the particles were isometric with a diameter of about 29 nm and a rounded rather than angular profile, but without clear substructure; some particles were penetrated by the stain. The particles remained intact in neutral sodium phosphotungstate. After isopycnic centrifugation in CsCl solution, preparations of particles formed a main band of mean density 1.377 g/ml and other fainter bands that varied in intensity and position in different preparations. In thin sections of carnations, no virus-like particles or cytological abnormalities were observed.     

Water inputs across a tropical montane landscape in Veracruz,Mexico: synergistic effects of land cover,rain and fog seasonality,and interannual precipitation variability

Land‐cover change can alter the spatiotemporal distribution of water inputs to mountain ecosystems, an important control on land‐surface and land‐atmosphere hydrologic fluxes. In eastern Mexico, we examined the influence of three widespread land‐cover types, montane cloud forest, coffee agroforestry, and cleared areas, on total and net water inputs to soil. Stand structural characteristics, as well as rain, fog, stemflow, and throughfall (water that falls through the canopy) water fluxes were measured across 11 sites during wet and dry seasons from 2005 to 2008. Land‐cover type had a significant effect on annual and seasonal net throughfall (NTF <0=canopy water retention plus canopy evaporation; NTF >0=fog water deposition). Forest canopies retained and/or lost to evaporation (i.e. NTF<0) five‐ to 11‐fold more water than coffee agroforests. Moreover, stemflow was fourfold higher under coffee shade than forest trees. Precipitation seasonality and phenological patterns determined the magnitude of these land‐cover differences, as well as their implications for the hydrologic cycle. Significant negative relationships were found between NTF and tree leaf area index (R²=0.38, P<0.002), NTF and stand basal area (R²=0.664, P<0.002), and stemflow and epiphyte loading (R²=0.414, P<0.001). These findings indicate that leaf and epiphyte surface area reductions associated with forest conversion decrease canopy water retention/evaporation, thereby increasing throughfall and stemflow inputs to soil. Interannual precipitation variability also altered patterns of water redistribution across this landscape. Storms and hurricanes resulted in little difference in forest‐coffee wet season NTF, while El Niño Southern Oscillation was associated with a twofold increase in dry season rain and fog throughfall water deposition. In montane headwater regions, changes in water delivery to canopies and soils may affect infiltration, runoff, and evapotranspiration, with implications for provisioning (e.g. water supply) and regulating (e.g. flood mitigation) ecosystem services.     

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.     

A scanning electron microscope technique for restoring deformed fossils

Deformed fossils which originally had a regular geometric outline, such as crinoid columnals, can be restored using a scanning electron microscope technique called tilt correction. This magnifies the specimen in one direction only. It is unsuitable for specimens where deformation has occurred unevenly and can also distort small structures while restoring the whole specimen. D Crinoid columnals, scanning electron microscope, tilt correction.     

THE OCCURRENCE OF BACILLUS CEREUS IN MILK AND ON DAIRY EQUIPMENT

SUMMARY: In a survey of milk obtained from individual farms and creameries, 87% of samples were found to contain fewer than one cell of Bacillus cereus /ml. The remaining 13%, although they all yielded low counts, showed that the organism tended to occur in milk received from particular farms and creameries. On investigating sources of contaminated milk, it was found that the organism was derived chiefly from cans which, after being emptied of milk, had been allowed to stand for a long time before being washed properly and 'sterilized'. The vegetative cells of B. cereus were shown to form spores readily in thin films of diluted milk, such as may occur in a rinsed can.     

Functional morphology of synostosial articulations in the crinoid column

The rarest articulation found in the crinoid column is the synostosis, in which adjacent articular facets are essentially planar. 'Synostoses' in the columns of post-Palaeozoic isocrinids are more correctly termed cryptosymplexies. comprising symplectial articulations which have become infilled by secondary calcite. Cryptosymplexial joints are totally inflexible and are the preferred sites of stem autotomy. Synostoses sensu stricto appear to have been limited to early Palaeozoic taxa, but this form of articulation was soon succeeded by the symplexy. Synostoses were probably commonest in meric columns which evolved from hohlwurzels and in which the main flexibility was along meric sutures, rather than between columnals. With the evolution of the holomeric columnal. a more flexible articulation between columnals was a functional necessity in order that the stem did not develop into a stiffened rod. The solution was the evolution of the symplexy. *** Crinoids, columnals. synostosis, functional morphology evolution.