Development of an immunosorbent assay for seed-borne Erwinia stewartii in corn seed

Polyclonal and monoclonal antibodies to the virulent Erwinia stewartii strain SS104 were produced in rabbits and mice, respectively, and used in a double sandwich ELISA (polyclonal antibodies) or an indirect ELISA (monoclonal antibodies). Specificity of the polyclonal and monoclonal antibodies was determined by testing 167 bacterial strains in the two protocols. All 44 E. stewartii strains tested, including 4 avirulent strains, were positive in both protocols. None of 17 bacterial strains, comprising 6 different bacterial genera found on plants, cross reacted in either assay. However, of 106 strains collected from corn plants and seeds which were determined not to be virulent E. stewartii, 7 strains cross reacted in the double sandwich ELISA using the polyclonal antibodies. One of these strains appeared to cross react in the indirect ELISA but the reaction was shown to be an interaction with the antimouse immunoglobulin rather than the specific monoclonal antibody;A double sandwich ELISA, using polyclonal and monoclonal antibodies, was developed to detect Erwinia stewartii in ground corn seed samples. Detection levels of E. stewartii in pure culture and mixed with corn seed tissue were compared in four ELISA procedures using polyclonal and monoclonal antibodies. The procedure most appropriate for a seed assay was a double sandwich ELISA using polyclonal antibodies for capture and monoclonal antibodies for detection. This assay detected E. stewartii antigen in seed from plants that had been inoculated with E. stewartii strain 9A (rif[superscript]+, nal[superscript]+) but not in seed produced by plants that were not inoculated. It was confirmed that viable E. stewartii were present in the seedlots that were positive by ELISA by recovery of strain 9A on rifampicin and nalidixic acid-amended agar plates. Analysis of four hundred individual seeds resulted in a strong ELISA response from 8 individual seeds and recovery of confluent growth of E. stewartii on respective amended agar plates. The other 392 seeds had a lower ELISA response and fewer E. stewartii colonies were recovered from 10 of them

Control of germ-band retraction in Drosophila by the zinc-finger protein HINDSIGHT

Drosophila embryos lacking hindsight gene function have a normal body plan and undergo normal germ-band extension. However, they fail to retract their germ bands. hindsight encodes a large nuclear protein of 1920 amino acids that contains fourteen C2H2-type zinc fingers, and glutamine-rich and proline-rich domains, suggesting that it functions as a transcription factor. Initial embryonic expression of hindsight RNA and protein occurs in the endoderm (midgut) and extraembryonic membrane (amnioserosa) prior to germ-band extension and continues in these tissues beyond the completion of germ-band retraction. Expression also occurs in the developing tracheal system, central and peripheral nervous systems, and the ureter of the Malpighian tubules. Strikingly, hindsight is not expressed in the epidermal ectoderm which is the tissue that undergoes the cell shape changes and movements during germ-band retraction. The embryonic midgut can be eliminated without affecting germ-band retraction. However, elimination of the amnioserosa results in the failure of germ-band retraction, implicating amnioserosal expression of hindsight as crucial for this process. Ubiquitous expression of hindsight in the early embryo rescues germ-band retraction without producing dominant gainof-function defects, suggesting that hindsight’s role in germ-band retraction is permissive rather than instructive. Previous analyses have shown that hindsight is required for maintenance of the differentiated amnioserosa (Frank, L. C. and Rushlow, C. (1996) Development 122, 1343-1352). Two classes of models are consistent with the present data. First, hindsight’s function in germ-band retraction may be limited to maintenance of the amnioserosa which then plays a physical role in the retraction process through contact with cells of the epidermal ectoderm. Second, hindsight might function both to maintain the amnioserosa and to regulate chemical signaling from the amnioserosa to the epidermal ectoderm, thus coordinating the cell shape changes and movements that drive germ-band retraction

Toxoplasma gondii in wild ruminants bred in game preserves and farms with production destined for human consumption in the Czech Republic.

Toxoplasma gondii is the causative agent of the most common parasitic infection in humans. Almost all warm-blooded animals, as well as humans, can act as intermediate hosts that harbour infective cysts in their tissues. Felids act as definitive hosts excreting oocysts in faeces. In humans, T. gondii can cause subclinical infection but also severe clinical disease with a wide range of symptoms, especially in immunocompromised individuals. The infection is usually asymptomatic in animals and is not recognized at either ante- or post-mortem inspection. The consumption of undercooked meat from infected animals is one of the most important routes by which the infection can be transmitted to humans. Handling of the organs and other tissues of game animals and eating their undercooked meat have been described as a risk of T. gondii infection. For diagnosis of toxoplasmosis, the combination of serological and molecular methods has been described as a suitable approach. Antibodies against T. gondii were detected in 20.8%, 50.0%, 23.1%, and 24.4% of red deer, sika deer, fallow deer and mouflons, respectively, coming from game preserves and farms in the Czech Republic. T. gondii DNA was found in the muscle tissue of red deer (8.3%) and mouflons (14.6%). The lower prevalence rates based on molecular screening could be due to the random distribution and low density of cysts in tissues of infected animals. Bearing in mind the increase in the number of hunted animals and the growing trend in game consumption, it is important to educate hunters and game meat consumers about the risk of exposure to this zoonotic infection during handling and consumption of the meat

The meat of goat kids and lambs as a possible source of Toxoplasma gondii for consumers

Toxoplasmosis is a worldwide zoonosis and the consumption of undercooked meat is a major risk factor for human infection. Antibodies to Toxoplasma gondii were found in 28.2% (11/39) and 27.8% (5/18) of home-slaughtered goat kids (n = 39) and lambs (n = 18) from four farms in the Czech Republic. The DNA of the parasite was detected in the tissues (diaphragm and/or lung) of 10.3% (4/39) of kids and 16.7% (3/18) of lambs. Although the consumption of kid and lamb meat is low in the Czech Republic, its consumption may become a source of Toxoplasma infection in humans

Metal-carbohydrates

Title from folder label.Project report form no. 1 dated September 9, 1966. Structure studies of metal-carbohydrate complexes / Mark A. Lamka -- Project report form no. 2 dated September 3, 1968. Structure studies of metal-carbohydrate complexes / Gerald F. Richards

How Do I Get There From Here? Attitudes Toward Different Modes of Transportation

The acceptance of multiple-occupant modes of transportation such as buses and carpools is an important factor in energy conservation. Two experiments are reported which show how attitudes toward different modes of transportation are influenced by interpersonal factors. Experiment 1 showed that individuals perceive differences in the characteristics of people who use different modes and that these differences are related to their own transportation preferences. Experiment 2 showed that the sex of each potential rider and whether or not each rider is an acquaintance of the respondent are important factors in carpooling. The implications of such results to policy makers are discussed

UDP-glycosyltransferase family in Haemonchus contortus: Phylogenetic analysis, constitutive expression, sex-differences and resistance-related differences

UDP-glycosyltransferases (UGT), catalysing conjugation of UDP-activated sugar donors to small lipophilic chemicals, are widespread in living organisms from bacteria to fungi, plant, or animals. The progress of genome sequencing has enabled an assessment of the UGT multigene family in Haemonchus contortus (family Trichostrongylidae, Nematoda), a hematophagous gastrointestinal parasite of small ruminants. Here we report 32 putative UGT genes divided into 15 UGT families. Phylogenetic analysis in comparison with UGTs from Caenorhabditis elegans, a free-living model nematode, revealed several single member homologues, a lack of the dramatic gene expansion seen in C. elegans, but also several families (UGT365, UGT366, UGT368) expanded in H. contortus only. The assessment of constitutive UGT mRNA expression in H. contortus adults identified significant differences between females and males. In addition, we compared the expression of selected UGTs in the drug-sensitive ISE strain to two benzimidazole-resistant strains, IRE and WR, with different genetic backgrounds. Constitutive expression of UGT368B2 was significantly higher in both resistant strains than in the sensitive strain. As resistant strains were able to deactivate benzimidazole anthelmintics via glycosylation more effectively then the sensitive strain, UGT368B2 enhanced constitutive expression might contribute to drug resistance in H. contortus

Pest categorisation of Pantoea stewartii subsp. stewartii

Following a request from the European Commission, the EFSA Plant Health Panel performed a pest categorisation of Pantoea stewartii subsp. stewartii (hereafter P. s. subsp. stewartii). P. s. subsp. stewartii is a Gram-negative bacterium that causes Stewart’s vascular wilt and leaf blight of sweet corn and maize, a disease responsible for serious crop losses throughout the world. The bacterium is endemic to the USA and is now present in Africa, North, Central and South America, Asia and Ukraine. In the EU, it is reported from Italy with a restricted distribution and under eradication. The bacterium is regulated according to Council Directive 2000/29/EC (Annex IIAI) as a harmful organism whose introduction and spread in the EU is banned on seeds of Zea mays. Other reported potential host plants include various species of the family Poaceae, including weeds, rice (Oryza sativa), oat (Avena sativa) and common wheat (Triticum aestivum), as well as jackfruit (Artocarpus heterophyllus), the ornamental Dracaena sanderiana and the palm Bactris gasipaes, but there is uncertainty about whether these are hosts of P. s. subsp. stewartii or of the other subspecies. The pest could enter the EU via host plants for planting (including seed) and via insect vectors from neighbouring countries. Host plants are widely distributed and climatic conditions are conducive in the EU. P. s. subsp. stewartii could spread by movement of host plants for planting (including seeds) and insect vectors. Impacts could occur on maize and rice. Methods to certify pest freedom of maize seeds are available. The main knowledge gaps concern the availability of vectors in the EU, the level of susceptibility of the maize cultivars grown in the EU, the virulence of strains in recent outbreaks, and the host range of the bacterium. The criteria assessed by the Panel for consideration as a potential quarantine pest are met

Impacts of Parasites in Early Life: Contrasting Effects on Juvenile Growth for Different Family Members

Parasitism experienced early in ontogeny can have a major impact on host growth, development and future fitness, but whether siblings are affected equally by parasitism is poorly understood. In birds, hatching asynchrony induced by hormonal or behavioural mechanisms largely under parental control might predispose young to respond to infection in different ways. Here we show that parasites can have different consequences for offspring depending on their position in the family hierarchy. We experimentally treated European Shag (Phalacrocorax aristoteli) nestlings with the broad-spectrum anti-parasite drug ivermectin and compared their growth rates with nestlings from control broods. Average growth rates measured over the period of linear growth (10 days to 30 days of age) and survival did not differ for nestlings from treated and control broods. However, when considering individuals within broods, parasite treatment reversed the patterns of growth for individual family members: last-hatched nestlings grew significantly slower than their siblings in control nests but grew faster in treated nests. This was at the expense of their earlier-hatched brood-mates, who showed an overall growth rate reduction relative to last-hatched nestlings in treated nests. These results highlight the importance of exploring individual variation in the costs of infection and suggest that parasites could be a key factor modulating within-family dynamics, sibling competition and developmental trajectories from an early age