Isoflavone profiles of red clovers and their distribution in different parts harvested at different growing stages

The isoflavone compositions and concentrations in the leaf, flower, petiole, and stem of 13 red clover cultivars were studied using high-performance liquid chromatography coupled with a diode array and a mass spectrometric detector with negative electrospray ionization. Different cultivars showed significantly different concentrations of individual and total isoflavones. The leaf contained the highest overall concentration, followed by the stem, petiole, and flower. Biochanin A and formononetin were the predominant isoflavones in all cultivars and all parts, along with eight other minor aglycones, daidzein, genistein, glycitein, irilone, orobol, pratensein, pseudobaptigenin, and prunetin, and four minor malonylglycosides, genistein-7-glucoside-6' '-malonate, orobol-7-glucoside-6' '-malonate, formononetin-7-glucoside-6' '-malonate, and biochanin A-7-glucoside-6' '-malonate. The isoflavone compositions and concentrations were also found to be different between red clover parts harvested at the early bud stage and the late flowering stage. Sample storage and handling prior to analysis were also found to be important. Samples in this study were kept at -5 degrees C for a few days before being freeze-dried and were found to contain mainly the aglycones of isoflavones. This may actually be an advantage in that "natural" and more bioactive isoflavones can be obtained without using chemical hydrolysis. Findings in this study therefore provide important information for developing isoflavone-rich red clovers and for optimizing harvest timing and choosing the right part of the red clover plant.     

Comparison of thermal dilution and electrical impedance dilution methods for measurement of cardiac output in standing and exercising horses

OBJECTIVE: To compare cardiac output measured in the pulmonary artery and a carotid artery by use of thermal and electrical impedance dilution. Animals-7 fit, clinically normal Standardbreds between 2 and 5 years of age. PROCEDURE: Transient changes in electrical impedance and temperature of blood were induced by bolus injections of ice-cold saline hypertonic (6% and 9% NaCl) solutions. Cardiac output was calculated by applying Stewart-Hamilton principles to the indicator dilution transients. Measurements were made during sequential exercise episodes on a level treadmill over approximately an 8-fold range of cardiac output values. RESULTS: We detected agreement between cardiac output determined by use of electrical impedance dilution at the pulmonary artery and carotid artery. Cardiac output from thermal dilution measured at the carotid artery exceeded that measured at the pulmonary artery. Cardiac output from the thermal dilution technique exceeded cardiac output from the electrical impedance dilution technique at both locations. CONCLUSIONS AND CLINICAL RELEVANCE: The electrical impedance indicator is conserved on first transit; therefore cardiac output measured by electrical impedance dilution at the carotid artery is reliable over a large range of values. Thermal dilution provides a larger estimate of cardiac output, compared with the electrical impedance dilution technique, probably because of a loss of indicator. The transpulmonary electrical impedance dilution technique may have potential for clinical application, particularly in animals in which catheterization of the pulmonary artery is not appropriate or blood loss must be minimized.     

Serum dopamine-beta-hydroxylase activity: sibling-sibling correlation

Dopamine-beta-hydroxylase activity is released into the blood with catecholamines from the adrenal medulla and sympathetic nerves. This enzyme activity has been measured in the blood of 317 normal children and 227 normal adults. A significant sibling-sibling correlation of serum dopamine-beta-hydroxylase values was found in the 94 sibling pairs tested. Frequency distributions of serum enzyme values in both children and adults suggest the existence of two populations with regard to serum activity of this enzyme.     

Thermohaline fine structure in an oceanographic front from seismic reflection profiling

We present acoustic images of oceanic thermohaline structure created from marine seismic reflection profiles across the major oceanographic front between the Labrador Current and the North Atlantic Current. The images show that distinct water masses can be mapped, and their internal structure imaged, using low-frequency acoustic reflections from sound speed contrasts at interfaces across which temperature changes. The warm/cold front is characterized by east-dipping reflections generated by thermohaline intrusions in the uppermost 1000 meters of the ocean. Our results imply that marine seismic reflection techniques can provide excellent spatial resolution of important oceanic phenomena, including thermohaline intrusions, internal waves, and eddies.     

Review—mechanism of action of herbicidal and fungicidal compounds on cell membranes

The eukaryotic cell membrane is thought to consist of a mobile bilayer of phospholipid, sometimes intercalated with sterols, in which peripheral and transmembrane proteins are embedded. This provides a model whereby the mode of action of many fungicidal and herbicidal compounds can be rationalised and understood. Some compounds, such as the polyene antibiotics, steroidal saponins and certain phytoalexins, induce membrane malfunction by direct insertion, often complexing with vital components. Others, such as paraquat and the nitrodiphenyl ether herbicides, cause membrane damage by inducing lipid peroxidations. Furthermore, there are many compounds, including the sterol-biosynthesis-inhibiting fungicides and the aryloxyphenoxypropionate and cyclohexanedione herbicides, which interfere with the biosynthesis of membrane components. Because membrane structure is fundamentally similar in eukaryotes, it is important to discover the reasons for any differential toxicity displayed by these compounds and, if necessary, to find ways of optimising desirable patterns of selectivity.     

Prospects and progress for Bacillus thuringiensis-based pesticides

Bacillus thuringiensis (Bt)-based insecticide products constitute the overwhelming majority of biopesticides but, despite having been commercially available for over 30 years, they have made little impact (<1%) on the crop-protection market as a whole. This has been largely due to poor cost-performance factors relative to synthetic organic pesticides. However, recent biotechnological advances—including genetic modification—combined with a variety of emerging opportunities, have created the prospect of the commercialisation of a new range of highly effective Bt-based biopesticides. Bioencapsulation of single-gene products—delta-endotoxins from selected Bt isolates—in killed Pseudomonad cells (Mycogen Corporation's ‘CellCap’ technology), offers a flexible delivery system with enhanced persistence. This versatile approach selects only the most appropriate biotoxins, which can be used to target a number of pest species. It is anticipated that Bt-based pesticides will continue to fill an increasing number of gaps in the panoply of synthetic crop-protection chemicals. Genetically modified products offer advantages in terms of efficacy, flexibility and safety but public concerns regarding perceived risks need to be addressed.     

Live Transport of Striped Bass and Rainbow Trout Using a Hidrostal Pump

Immediate and delayed (96 h) mortality, descaling, and injury rates of striped bass Morone sax-atilis and rainbow trout Oncorhynchus mykiss that were inserted into the entrance (suction side) of a Hidrostal pump were compared to those of control fish that were inserted at the exit (pressure side). Comparisons were made in 158-paired trials of striped bass and 86 trials with rainbow trout. The Hidrostal pump had no significant effect on immediate or delayed (96 h) mortality. Immediate mortality for striped bass and rainbow trout averaged 0.1 and 0%, respectively, and delayed mortality averaged 2.9 and 0.1%, respectively. Mean scale loss after passage for striped bass and rainbow trout was low (0.2 and 1.0%, respectively). Frequency of injury to the head, eyes, skin, and tins of pumped striped bass averaged 1.9, 2.8, 1.9, and 18.7%, respectively, and those of rainbow trout averaged 2.3, 0, 2.4, and 3.1%. No significant relationships were detected between fish mortality and pump speed, injected fish density, and debris load. Results suggest that large Hidrostal pumps have the capacity to transport live striped bass and rainbow trout at high density (1-6 fish/L) with little mortality and body injury.     

Differences in ascorbate and glutathione levels as indicators of resistance and susceptibility in Eucalyptus trees infected with Phytophthora cinnamomi

In this study we investigated the role that ascorbate (AA) and glutathione (GSH) play in the plant pathogen interaction of susceptible Eucalyptus sieberi L. A. Johnson and resistant Eucalyptus sideroxylon Woolls with Phytophthora cinnamomi Rands root infection. In a glasshouse study, seedlings were grown in soil-free plant boxes to facilitate the inoculation of the root systems by a P. cinnamomi zoospore solution. Ascorbate and GSH concentrations were measured in infected roots and leaves, along with leaf gas exchange, chlorophyll fluorescence and carbohydrate concentrations over a time course up to 312 h (13 days) post-inoculation (pi). At the early stages of infection (from 24 h pi), significant decreases in AA and GSH concentrations were observed in the infected roots and leaves of the susceptible E. sieberi seedlings. At the later stage of infection (312 h pi), the earlier AA decreases in the leaves of infected plants had become significant increases. In contrast, late, significant AA increases in the absence of any GSH changes were observed in the infected roots of the resistant E. sideroxylon seedlings. In E. sideroxylon leaves, a significant GSH increase occurred at 24 h pi; however, by 312 h pi the earlier increase had become a significant decrease, while no changes occurred in AA. In E. sieberi, photosynthesis (A), stomatal conductance (g(s)) and PSII quantum efficiency (Φ(PSII)) were reduced by ～60, 80 and 30%, respectively, in infected plants and remained significantly lower than uninfected controls for the duration of the experiment. Significant reductions in these parameters did not occur until later (120 h pi for g(s) and 312 h pi for A and Φ(PSII)), and to a lesser extent in the resistant species. Non-structural carbohydrate analysis of roots and leaves indicate that carbohydrate metabolism and resource flow between shoots and roots may have been altered at later infection stages. This study suggests that reduced antioxidant capacity, leaf physiological function and carbohydrate metabolism are associated with susceptibility in E. sieberi to P. cinnamomi infection, while AA increases and new root formation were associated with resistance in E. sideroxylon.