Enantioselective analysis of methyl-branched alcohols and acids in rhubarb (Rheum rhabarbarum L.) stalks

The enantiomeric compositions of 2-methylbutanol (1), 4-methylhexanol (2), 2-methylbutanoic acid (3), and 4-methylhexanoic acid (4) present in rhubarb (Rheum rhabarbarum L.) stalks were determined. Enantiodifferentiation was achieved via multidimensional gas chromatography using heptakis(2,3,6-tri-O-ethyl)-beta-cyclodextrin as a chiral stationary phase. For all compounds the enantiomeric ratios were in favor of the (R)-enantiomers. The alcohols (1 and 2) exhibited generally high excesses of the (R)-enantiomers, the ratios varying slightly from batch to batch. For the acid (3) a rather narrow range averaging 65% (R):35% (S) was observed. The procedure applied to isolate the volatiles (vacuum headspace technique, simultaneous distillation--extraction, liquid--liquid extraction) had no significant impact on the enantiomeric ratios. The study describes for the first time a plant used as food material in which 2-methyl-branched volatiles are not nearly exclusively present as (S)-enantiomers. This information enlarges the current regulatory knowledge regarding the classification of these important flavor compounds as "natural" on the basis of their enantiomeric ratios.     

Effects of insecticides on acetylene reduction by alfalfa, red clover and sweetclover

Seven organophosphate and carbanate insecticides were tested for their effects on C₂H₂-reduction by alfalfa (Medicago sativa L.), sweetclovcr (Melilotus alba L.) and red clover (Trifolium pratense L.). Plants were grown in vitro for 21 days on nonstcrile vermiculite or soil substrates. Oftanol^® was inhibitory to most plants on both soil and vermiculite. Carbofuran's inhibitory effect was almost entirely limited to soil-grown plants. Carbaryl, aldicarb, chlorpyrifos, and terbufos were inhibitory to certain plants under some conditions. Phosmet was the least toxic. Significant differences were observed in toxicity which were dependent on the growth substrate used. The effects of carbamates tended to be restricted to plants grown on soil substrates rather than on vermiculite. Loss of C₂H₂-reducing ability was usually correlated with inhibition of nodule formation. The insecticides did not inhibit growth of Rhizobium meliloti or R. trifolii in broth culture.     

Collagen fiber architecture of the periodontal ligament in equine cheek teeth

The objective of this study was to examine the spatial arrangement of the fiber apparatus of the equine periodontium which is supposed to meet two contrary requirements: (1) to attach the tooth firmly and elastically to the alveolar bone; and, to be appropriately remodeled and reconstructed in order to facilitate the prolonged eruption of the tooth. Specimens of periodontal ligament were obtained from the buccal and lingual/palatal aspects of the first molars from the maxilla and mandible of 12 horses. The animals were assigned to three age groups. Histological sections were prepared from three specific horizontal levels of the periodontal ligament and examined with conventional and polarized-light microscopy. At the gingival level, collagen fascicles (diameter > 200 microm) were densely packed. Their spatial alignment was the same in all age groups. The architecture of the collagen fiber apparatus differed at the middle and apical levels in the three age groups. There was a clear distinction between fibers, bundles, and fascicles. Bundling of collagen fibers, density of the fiber arrangement, and collagen fascicles with an alveolo-cemental orientation increased with age. The collagen fiber apparatus of the equine periodontal ligament is highly adaptive, responding continuously to the dynamic changes in the periodontal environment. Site-specific arrangements and age-dependent structural variations are assumed to maintain tooth support as the reserve crown gradually decreases in length with progressive dental attrition. Most of the age-dependent changes to the periodontal ligament in teeth examined in this study occurred at the apical level. The apical region of young teeth had no periodontal attachment, while the roots of older teeth were firmly attached to the alveolus. When evaluating periodontal ligament development, the individual tooth's 'dental age' should be considered rather than the animal's age to account for individual tooth eruption times.     

Risks for infection of strawberry plants with an aerosolized inoculum of <Emphasis Type="Italic">Xanthomonas fragariae</Emphasis>

Xanthomonas fragariae is the causative agent of angular leaf spot of strawberry, a quarantine organism in plant propagation material in the European Union. Field experiments were conducted to assess the risks for infection of strawberry plants through dispersal of an aerosolized inoculum. In practice, pathogen aerosols can be formed during mowing of an infected crop or by water splashing on symptomatic plants during overhead irrigation or rain. In our experiments, aerosols were generated by spraying suspensions of X. fragariae with a density of 10⁸ cfu ml^?1 or water under pressure vertically up into the air. In strawberry plants (cv Elsanta) placed at 1.3, 5 and 10 m distance downwind from the spray boom, infections were found, as evidenced with a combination of dilution–plating and molecular techniques, but more frequently in plants wetted prior to inoculation than in plants kept dry. A logarithmic decrease in infection incidence was found with the distance to the inoculum source. Symptomatic plants were found up to 5 m distance from the inoculum source. No infected plants were found in plants placed 4 m upwind or treated with water. In glasshouse studies, it was shown that under conditions favorable for disease development, spray-inoculation of strawberry plants with estimated densities of X. fragariae as low as 2000 cfu per plant were able to cause symptoms both in cv Elsanta and cv Sonata. Results indicate that there is a considerable risk on infections of strawberry plants exposed to aerosolized inoculum.     

Uptake Studies on a Fluorescein-Labelled Seed Oil Adjuvant in Abutilon theophrasti, Sinapis arvensis and Beta vulgaris

Though adjuvants are abundant in almost every pesticide solution, their mode of action is still not completely clear. Studies on their way through the cuticle are quite difficult due to a lack of radiolabelled surfactants. In this study we want to present the results of an experiment conducted to evaluate the mode of action of an ethoxylated soybean oil (ESBO) adjuvant. To evaluate the route of ESBO through the cuticle it was labelled with fluorescein and applied to one leaf of different test species (Abutilon theophrasti, Sinapis arvensis and Beta vulgaris). Treated leaves were harvested and rinsed with either deionised water, methanol/water or chloroform. The fluorescein content of washed leaves and the solution in which they were washed were analysed with High-Performance Liquid Chromatography (HPLC) coupled with an UV detector. Results lead to the assumption that ESBO passed through the cuticle. If this holds true, ESBO was able to reach the underlying cell tissue where it might have been metabolised or even translocated to other plant parts. Though a lot of research has to be conducted on the mechanism and mode of action of adjuvants, this study gives an approach to investigate the behavior of foliar applied adjuvants.     

Expression and functional characterization of killer whale (Orcinus orca) interleukin-6 (IL-6) and development of a competitive immunoassay

Interleukin-6 (IL-6) is a cytokine that can reach detectable systemic levels and is a major inducer of the acute phase response. As such, clinical assays to identify this cytokine in mammalian sera are of diagnostic value. A 558 base-pair (bp) fragment of killer whale IL-6 was cloned and expressed as a 21 kDa protein in Escherichia coli. Biological activity of the recombinant killer whale IL-6 (rkwIL-6) was demonstrated using the IL-6-dependent B9 mouse hybridoma cell line; acute phase sera from a killer whale and supernatants from lipopolysaccharide (LPS)-stimulated killer whale peripheral blood mononuclear cells (PBMCs) also supported the proliferation of the B9 hybridoma. Rat anti-mouse IL-6 receptor antibody effectively blocked biological activity of all three sources of IL-6. Polyclonal antisera, specific for the recombinant protein, were obtained by successive immunization of a rabbit with rkwIL-6. The polyclonal antibody was capable of neutralizing the biological activity of both recombinant and native kwIL-6. A competitive enzyme-linked immunosorbent assay (ELISA) was developed using the polyclonal rabbit anti-rkwIL-6 and the recombinant protein; sensitivity of the assay was in the range of 1 ng/ml. The ELISA was subsequently used to identify the presence of native IL-6 in acute phase sera of two species of delphinidae, a killer whale and a bottlenose dolphin. The application of quantitative cytokine assays as diagnostic tools for monitoring cetacean health are becoming feasible as many animals are now being trained for fluke presentation, making blood collection a routine procedure.     

Normal structure and age-related changes of the equine retina

Investigations of the pathophysiology of ocular diseases require a detailed knowledge of the microanatomy of the eye. The available information is still inadequate for the equine retina despite the importance of eye diseases in equine medicine. Here we provide a comprehensive analysis of the histologic features of the horse eye as a reference for future studies. Thirty normal eyes of 15 healthy horses were examined immediately after slaughter. The retina of the horse differs considerably in the degree and quantity of neurons and glial elements as well as in vascular patterns compared to the retina of other domestic animals. Morphometric analysis revealed that the thickness of the retina varies between 80 microm at the ora serrata and 250 microm medial to the optic disc. Approximately 90% of the equine retina is comparatively thin (< 130 microm). This is a physiologic response to the distance that oxygen can diffuse in avascular retina. Ganglion cells form a single layer in all parts of the retina. The majority of ganglion cells are very large Nissl-positive cells. Small Nissl-negative ganglion cells are less abundant. A high ganglion cell density is found only in the central area. Vascularization is virtually absent from the retina with the exception of a narrow strip around the disc of the optic nerve, as revealed by lectin histochemistry. Light microscopy of the eyes of older horses repeatedly revealed cystoid degenerations in the retina adjacent to the pars plana of the ciliary body, as well as a destruction of the regular layering of the peripheral region of the retina.     

Socioeconomic Determinants of Fruits Consumption Among Students of the Federal University of Agriculture,Abeokuta, Ogun State,Nigeria

Fruits are important components of a healthy diet. They are a good source of vitamins, minerals, proteins, and dietary fibers. The study was carried out in the Federal University of Agriculture, Abeokuta, Ogun State, Nigeria with the major objective to analyze the determinants of fruit consumption among students. A multistage sampling procedure was used to select 100 students and data were collected with the aid of a well-structured questionnaire. The mean age was 27 years and 52% of the sampled students were male with a mean stipend of ?14,511.77 of which about ?307 is spent on fruit consumption. Apple was most preferred by the respondents due to taste. The regression analysis indicated that marital status, amount of stipend received, parental education level, availability of fruits, and nature of study were variables that significantly determine consumption of fruits among the students. Provision of physical access by giving space to either the growers or sellers of fruits in the University campus and financial access with more stipends to raise what students spent on the average per months will significantly change their fruits consumption pattern.