Glyphosate in fisheries management

Glyphosate is the active ingredient of the broad-spectrum, translocated herbicide Roundup. Glyphosate is cleared for safe use in or near watercourses, being rated virtually non-toxic by the World Health Organisation. Trials in and alongside Irish fishery watercourses first commenced in 1989 and are continuing to date. The aim of this work is to evaluate the product's efficacy in clearing nuisance reed species in recreational fisheries. The longevity of control and impact on the habitat and its fauna is also investigated. Trials in canal fisheries have demonstrated the capacity of glyphosate to remove obstructive stands of reeds (mainly Schoenoplectus lacustris, Glyceria maxima, Phragmites australis, Sparganium erectum and Typha latifolia), so creating reed-free areas and swims for anglers. These swims remained open for three years following a single application. In 1992 a trial over a 3 km length of the River Boyne, a renowned salmonid fishery, was undertaken. The results clearly demonstrated the ability of glyphosate to provide long-term control of dense (354 shoots m^–2) Schoenoplectus infestations in a large watercourse. In the year following, less than one shoot per m² was present in the channel. In 1994 a small increase in density (7.6 shoots m^–2 was recorded, so enabling unobstructed angling in a stretch of river that had been virtually unfishable for years. Trout (Salmo trutta L.) and salmon (Salmo salar L.) also used the newly exposed gravels for spawning in the winter of 1993, thereby improving fish recruitment and production in the fishery.     

Toward Practical Biological Control of Parasitic Nematodes in Domestic Animals

In a series of laboratory and field experiments where the nematophagous fungus Arthrobotrys oligospora was mixed directly with feces it has been demonstrated that it is possible to use nematophagous fungi for biological control of animal parasitic nematodes. A procedure used for selection of nematophagous fungi that can pass the digestive tract of ruminants, horses, and pigs is described. The selected fungus, Duddingtonia flagrans, has been used in further field experiments, and the results have confirmed that by the addition of D. flagrans to feed supplement it is possible to reduce the parasitic burden significantly.     

Pre-inoculation of Ri T-DNA-transformed pea roots with Pseudomonas fluorescens inhibits colonization by Pythium ultimum Trow: an ultrastructural and cytochemical study

The influence exerted by Pseudomonas fluorescens, strain 63-28R, in stimulating plant defense reactions was investigated using an in-vitro system in which Ri T-DNA-transformed pea (Pisum sativum L.) roots were subsequently infected with Pythium ultimum. Cytological investigations of samples from P. fluorescens-inoculated roots revealed that the bacteria multiplied abundantly at the root surface and colonized a small number of epidermal and cortical cells. Penetration of the epidermis occurred through the openings made by the disruption of the fibrillar network at the junction of adjacent epidermal cell walls. Direct cell wall penetration was never observed and bacterial ingress into the root tissues proceeded via an intercellular route. Striking differences in the extent of fungal colonization were observed between bacterized and non-bacterized pea roots following inoculation with P. ultimum. In non-bacterized roots, the pathogen multiplied abundantly through most of the tissues while in bacterized roots, pathogen growth was restricted to the epidermis and the outer cortex. At the root surface, the bacteria interacted with the pathogen, in a way similar to that observed in dual culture tests. Most Pythium cells were severely damaged but fungal penetration by the bacteria was never observed. Droplets of the amorphous material formed upon interaction between the bacteria and the host root were frequently found at the fungal cell surface. Incubation of sections with a -1,4-exoglucanase-gold complex revealed that the cell wall of markedly altered Pythium hyphae was structurally preserved. Successful penetration of the root epidermis was achieved by the few hyphae of P. ultimum that could escape the first defensive line in the rhizosphere. Most hyphae of the pathogen that penetrated the epidermis exhibited considerable changes. The unusual occurrence of polymorphic wall appositions along the host epidermal cells was an indication that the host plant was signalled to defend itself through the elaboration of physical barriers.Abbreviations AGL Aplysia gonad lectin - PGPR plant growth-promoting rhizobacteria The authors wish to thank Sylvain Noël for excellent technical assistance. This study was supported by grants from the Fonds Québécois pour la formation de chercheurs et l'Aide à la Recherche (FCAR), the Natural Sciences and Engineering Council of Canada (NSERC) and the Ministère de l'Industrie, du Commerce, de la Science et de la Technologie (SYNERGIE).     

Some improvements in the quality of NAA procedures and the reliability of the results

After considering the need for quality control in NAA, the concept of quality in NAA procedures themselves is discussed, and some important factors identified. Two approaches to improve quality are then described in more detail. The first concerns the unique ability of NAA using different isotopic reactions and different modes (INAA/RNAA) to provide independent data sets in the same laboratory, thus allowing internal validation or crosschecking. The second discusses the need for chemical yield measurements in RNAA and the advantages of the radioisotopic tracer technique. Some recent advances and further possibilities for this use of tracers are listed.     

Interlaboratory Reproducibility In Reporting Inadequate Cervical Smears—A Multicentre Multinational Study

A set of 300 vaginal smears was interpreted by 13 cytologists from six European laboratories, who were requested to report inadequate and suboptimal smears. the set had been appropriately seeded to reach approximately 10% inadequate and 20% suboptimal smear frequency. According to the majority report, 230 smears were classified as adequate (76.7%), 43 as inadequate (14.3%), and 27 as suboptimal (9.0%). Agreement with the majority report ranged from 52% to 91% (average 78%). Kappa statistics for reporting inadequate smears showed a high level of agreement for five cytologists, and fair to good agreement for eight. In contrast, K statistics for reporting suboptimal smears showed fair to good agreement with the majority report only in five instances, whereas agreement was poor for eight cytologists. ‘Inadequate smear’rates may be used to compare the quality of smears received in different laboratories, as there is a high level of agreement among cytologists as to what constitutes an inadequate smear. However, this is not true for ‘suboptimal smear’ rates, and more precise reporting criteria must be defined and tested if an intermediate category is to be retained to report poor quality smears: more precise reporting criteria must be defined and tested if an intermediate category is to be retained to report poor quality smears. Une série de 300 frottis cervico-vaginaux a été examinee par 13 cytologistes appartenant à 6 laboratoires européens auxquels il avait été demandé de signaler les frottis inadéquats et sub-optimaux. Cette série de frottis a été constituée de façon à atteindre approximativement une fréquence de 10% de frottis inadéquats et de 20% de frottis sub-optimaux. Si I'on considère les réponses faites par la majorité des cytologistes, 230 frottis ont été classés adéquats (76,7%), 43 classés inadéquats (14,3%), et 27 comme sub-optimaux (9,0%). La concordance avec les réponses de la majorité des cytologistes varie de 52%à 91% (moyenne 78%). Concernant le signalement des frottis inadéquats, le test Kappa est excellent pour 5 cytologistes et moyen à bon pour les 8 autres. Au contraire, pour le signalement des frottis sub-optimaux, le test Kappa montre un accord moyen à bon avec les réponses de la majorité seulement dans 5 cas alors que I'agrément est mauvais pour 8 cytologistes. La fréquence des frottis inadéquats peut être utilisée pour comparer la qualité de prélèvement du frottis dans différents laboratoires, alors que les comparaisons de la fréquence des frottis sub-optimaux sont discutables, du fait d'un biais de diagnostic évident. Des critéres plus précis pour le signalement des frottis sub-optimaux doivent étre définis et testés si cette catégorie doit être retenue pour rapporter les frottis de mauvaise qualité. 300 Abstriche wurden durch 13 Zytologen aus 6 europäischen Laboratorien hinsichtlich der Kriterien ‘unbrauchbar’und ‘suboptimal’beurteilt. Die Sammlung enthielt etwa 10% unbrauchbare und 20% suboptimale Präparate. Mehrheitlich wurden 230 Abstriche als auswertbar (76,7%), 43 als unbrauchbar (14,3%) und 27 als suboptimal (9,0%) bezeichnet. Die Statistik ergab hinsichtlich der unbrauchbaren Abstriche eine ausgezeichnete Ûbereinstimmung für 5 und eine gute Ûbereinstim-mung für 8 Zytologen. Demgegenüber zeigte sich hinsichtlich der Beurteilung suboptimal nur 5mal eine gute und 8mal eine schlechte Ûbereinstimmung. Damit ist die Kategorie suboptimal ungeeignet zum Vergleich und bedarf einer genaueren Definition wenn sie für die Qualitätskontrolle eingesetzt werden soll.     

Seasonality ofOrmia depletaand Limits to Its Spread

Ormia depleta(Wiedemann) (Diptera: Tachinidae), a South American fly that homes on the calling songs of its hosts, was brought from Piracicaba, Brazil; colonized; and released in Florida for the biological control ofScapteriscusspp. mole crickets. It became established at some release sites and rapidly spread through most of peninsular Florida. The seasonal distributions of phonotactic females in Florida differed from the single summer peak recorded at Rio Claro and Piracicaba, Brazil (23° S). Near Bradenton (27° N), spring and fall peaks with a summer hiatus were quickly established and remain evident. At two sites near Gainesville (30° N), a strong fall peak and a modest-to-none spring peak developed. Peaks of phonotactic females seem to follow times of peak host availability and sometimes coincide with minima of host availability. Limits to geographical expansion ofO. depletaare poorly understood. At Gainesville, the site of earliest introduction, establishment was rapid and soundtrap catches increased for the first 3 years, exceeding 1000 per year at one site. Catches then declined for 3 years, almost reaching zero in 1994. On the other hand, annual sound-trap catches ofO. depletaat Bradenton exceeded 1000 in <2 years and have remained above that level for 5 years. Winters in Gainesville are more severe than those in Bradenton, but minimum winter temperatures in Gainesville were substantially lower duringO. depleta's increase than during its decline. Perhaps mild winters cause the flies to become active early—only to starve for lack of adequate winter nectar sources.O. depletamay yet spread to the northern limits of itsScapteriscushosts as present populations adapt to new environments. Or farther spread may require that new strains be introduced from more southerly sites in South America.     

The control of respiration in wheat (Triticum aestivum L.) leaves

The aim of this work was to discover whether the respiration of wheat (Triticum aestivum L. cv. Huntsman) leaves, transferred to darkness after 7 h photosynthesis, showed an initial period of wasteful respiration. For young and old leaves, CO₂ production and O₂ uptake after 7 h photosynthesis were up to 56% higher than at the end of an 8-h night. The maximum catalytic activities of citrate synthase (EC 4.1.3.7), aconitase (EC 4.2.1.3), fumarase (EC 4.2.1.2) and cytochrome-c oxidase (EC 1.9.3.1) at the end of the day did not differ from those at the end of the night. Changes in the contents of glucose 6-phosphate, fructose-1,6-bisphosphate, dihydroxyacetone phosphate, and -ketoglutarate did not as a group parallel the changes in the rate of respiration. The detailed distribution of label from [U-¹⁴C] sucrose supplied to leaves in the dark was similar at the end of the day and the end of the night. No correlation was observed between the rates of leaf respiration and extension growth. It is argued that the higher rate of respiration at the beginning of the night cannot be attributed to wasteful respiration.Abbreviation RQ respiratory quotient We thank Dr H. Thomas and Professor C.J. Pollock, Institute for Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, UK for their generous help in measuring leaf extension. R.H.A. thanks the Science and Engineering Research Council for a studentship.     

Skeletal muscle: A paradigm for testing principles of bioenergetics

Muscular activity converts chemical energy into useful work and metabolism restores muscle to its original state. This essay explores the organization and interactions of the regulatory system(s) which allow this energy balance to occur. The term energy balance is used in a biochemical rather than a thermodynamic sense—concerned not with deductions from the physical principles of thermodynamics, but rather with those enzymatic processes which nature evolved and which operate at remarkably fixed stoichiometry. Energy balance is a statement of conservation of energy put into biochemical observables.³¹P NMR spectroscopy is one of the most useful techniques for investigating these questions quantitatively under physiological conditionsin vivo. The author (1) describes the rules or principles of biochemical energy balance; (2) discusses sample results from human muscle to demonstrate its use in studying this class of questions; (3) presents a simple model of integrated cellular respiration to demonstrate its sufficiency to account for the main observations.     

Regulation of energy metabolism in liver

Energy metabolism in liver has to cope with the special tasks of this organ in intermediary metabolism. Main ATP-generating processes in the liver cell are the respiratory chain and glycolysis, whereas main ATP-consuming processes are gluconeogenesis, urea synthesis, protein synthesis, ATPases and mitochondrial proton leak. Mitochondrial respiratory chain in the intact liver cell is subject to control mainly by substrate (hydrogen donors, ADP, oxygen) transport and supply and proton leak/slip. Whereas hormonal control is mainly on substrate supply to mitochondria, proton leak/slip is supposed to play an important role in the modulation of the efficiency of oxidative phosphorylation.