Interplasmid transposition of the mariner transposable element in non-drosophilid insects

Plasmid-based transposition assays were performed in developing embryos of the Australian sheep blowfly Lucilia cuprina and the Queensland fruit fly Bactrocera tryoni, using the mariner transposable element from Drosophila mauritiana. Transposition products were recovered that were identical in structure to those recovered from D. melanogaster. Only sequences delimited by the mariner terminal repeats were transposed and all insertions occurred at TA residues, and duplicated these. These are the hallmarks of mariner transpositions observed in the chromosomes of D. melanogaster and D. mauritiana, indicating that the plasmid-based assays are accurate indicators of mariner transposition activity. The recovery of precise transposition products from L. cuprina and B. tryoni demonstrates that mariner should be capable of producing germline transformants in these species. The results obtained from these assays suggests that they will be extremely useful in determining if mariner can transpose in other non-drosophilid insects and for investigating factors that might affect mariner transposition frequency.     

The effect of concentrated smoke products on the restoration of highly disturbed mineral sands in southeast Victoria

Summary Recent studies have recognized the potential of broad‐scale surface application of smoke compounds for enhancing germination from the soil seed‐bank in fire‐prone vegetation communities. Results suggest that smoke technology may play, in the future, a significant role in the restoration and management of areas supporting indigenous vegetation. An important step in the development of smoke‐based restoration tools is the conduct of in situ field trials in a range of geographical locations and environmental conditions. However, most of the published work on the effectiveness of smoke products in promoting seedbank germination has been conducted at sites in southwestern Australia. The present study examines the effect of commercially available smoke‐water products on the regeneration of a highly disturbed former mine‐site at the Royal Botanic Gardens Cranbourne, in southeastern Victoria. Various combinations of concentrated smoke products and topsoil harvested from a nearby heathy woodland community were applied to exposed, uniform mineral sands to test their effect on seedling density and species richness of regrowth. The trials showed that after 12 months a number of common, herbaceous species including Austrodanthonia setacea, Opercularia varia and Platysace heterophylla were recorded in significantly higher numbers in areas treated with a commercial smoke‐water. However, there was no overall improvement in the density of seedlings or the richness of species as a result of the application of the smoke products. Similarly, total seedling density and species richness were not affected by the addition of topsoil, either alone or in combination with smoke products.     

Anaerobic Degradation of Benzene, Toluene, Ethylbenzene, and Xylene Compounds by Dechloromonas Strain RCB

Dechloromonas strain RCB has been shown to be capable of anaerobic degradation of benzene coupled to nitrate reduction. As a continuation of these studies, the metabolic versatility and hydrocarbon biodegradative capability of this organism were investigated. The results of these revealed that in addition to nitrate, strain RCB could alternatively degrade benzene both aerobically and anaerobically with perchlorate or chlorate [(per)chlorate] as a suitable electron acceptor. Furthermore, with nitrate as the electron acceptor, strain RCB could also utilize toluene, ethylbenzene, and all three isomers of xylene (ortho-, meta-, and para-) as electron donors. While toluene and ethylbenzene were completely mineralized to CO₂, strain RCB did not completely mineralize para-xylene but rather transformed it to some as-yet-unidentified metabolite. Interestingly, with nitrate as the electron acceptor, strain RCB degraded benzene and toluene concurrently when the hydrocarbons were added as a mixture and almost 92 μM total hydrocarbons were oxidized within 15 days. The results of these studies emphasize the unique metabolic versatility of this organism, highlighting its potential applicability to bioremediative technologies.     

The Role of Clostridium perfringens in the Growth Response of Chicks to Dietary Penicillin

S ummary . The previous observation that Clostridium perfringens is responsible for penicillin-relieved growth depression in chicks has been reassessed. The administration of Cl. perfringens to germfree chicks, to birds harbouring a non-growth depressing gut flora and to birds reared in an environment free from Cl. perfringens was without effect on growth rate. No correlation was observed in conventional chicks between the incidence of growth depression and the presence of Cl. perfringens in the gut of the chicks one day after food was first given.     

Immune protection against experimental autoimmune encephalomyelitis: optimal conditions and analysis of mechanism

Protection against experimental autoimmune encephalomyelitis (EAE) was studied in the guinea pig and the Lewis rat. Basic protein of myelin (BPM) injected in incomplete Freund's adjuvant (IFA) gave solid protection against subsequent challenge with normally encephalitogenic doses of BPM in complete Freund's adjuvant (CFA). Protection depended on the amount of BPM in IFA injected and on the duration of the interval between protection and encephalitogenic challenge with BPM in CFA. Notably, protection was long lasting; it remained demonstrable, to some degree for 52 weeks in guinea pig and 32 weeks in rats, these being the longest intervals tested.Protection could not be correlated with serum antibody levels to BPM, and was afforded in the guinea pig by the injection, in IFA, of a synthetic peptide matching residues 112–122 of human BPM; this peptide produced no detectable serum antibody to BPM. Protected guinea pigs had intact cell-mediated immunity to BPM, as measured by inhibition of macrophage migration in vitro. The mechanism of protection may involve the production, following injection of BPM in IFA, of a class of suppressor thymic lymphocytes capable of overriding otherwise encephalitogenic thymic lymphocytes.     

Measurement of the rate of stomach emptying using Indium-113m and a 10-crystal rectilinear scanner

Accurate reproducible measurements of the rate of gastric emptying have only been possible since the advent of external radionuclide detection techniques. Indium-113m and a 10-crystal rectilinear scanner have been employed to measure stomach emptying rates. The technique is simple, the results reproducible and it has proved ideal for assessing the results of drug therapy in patients with gastric retention. In the normal individual the T50% was 42 to 95 minutes, and the relationship between counts and time was, to first approximation, a linear function.     

A review of the global distribution of Alexandrium minutum (Dinophyceae) and comments on ecology and associated paralytic shellfish toxin profiles,with a focus on Northern Europe

Alexandrium minutum is a globally distributed harmful algal bloom species with many strains that are known to produce paralytic shellfish toxins (PSTs) and consequently represent a concern to human and ecosystem health. This review highlights that A. minutum typically occurs in sheltered locations, with cell growth occurring during periods of stable water conditions. Sediment characteristics are important in the persistence of this species within a location, with fine sediments providing cyst deposits for ongoing inoculation to the water column. Toxic strains of A. minutum do not produce a consistent toxin profile, different populations produce a range of PSTs in differing quantities. Novel cluster analysis of published A. minutum toxin profiles indicates five PST profile clusters globally. Some clusters are grouped geographically (Northern Europe) while others are widely spread. Isolates from Taiwan have a range of toxin profile clusters and this area appears to have the most diverse set of PST producing A. minutum populations. These toxin profiles indicate that within the United Kingdom there are two populations of A. minutum grouping with strains from Northern France and Southern Ireland. There is a degree of interconnectivity in this region due to oceanic circulation and a high level of shipping and recreational boating. Further research into the interrelationships between the A. minutum populations in this global region would be of value.