Flavones from Struthiola argentea with anthelmintic activity in vitro

Parasitic diseases caused by helminthes lead to significant health hazards to animals resulting in enormous economic impact. While a number of anthelmintics are currently available, all are encountering resistance and ones with a mode of action are needed. We report herein bioassay-guided isolation of three anthelmintic flavones 1-3, including the flavone, 5,6,2',5',6'-pentamethoxy-3',4'-methylenedioxyflavone (3) from the methanol extract of Struthiola argentea (Thymelaeaceae). The structure of 3 was elucidated by analysis of its 1D and 2D NMR and MS data. The two major flavones produced by this plant were also isolated and identified as yuankanin (4) and amentoflavone (5). A number of flavones related to the compounds isolated from S. argentea were acquired and tested to ascertain structure activity relationships. The isolation, structure, anthelmintic activity and structure activity relationships of the flavones are described. Compound 3 exhibited the most potent in vitro activity with 90% inhibition of larval motility at 3.1 microg/mL and compound 15 showed modest in vivo activity.     

Fluorometric quantitation of cellular and nonprotein thiols

A microfluorometric assay for thiols has been developed using the thiol-specific fluorochrome N-[4-(7-diethylamino-4-methyl-3-coumarinyl)phenyl]maleimide (CPM). The technique may be used to quantitate either cellular or plasma thiols over a range of 0.01 to 3.0 nmol and may be used with as few as 1-3 X 10(5) cells giving highly proportional and reproducible results. Values for nonprotein thiols obtained with this assay agree well with previous reports on glutathione (GSH) levels for both lymphocytes and plasma. Readings are determined with the aid of an automated fluorescence microplate reader which allows up to 96 samples, including standards, to be read at the same time. Cellular thiols accessible after lysis were also quantitated before and after treatment of intact cells with various thiol-reactive chemicals. Interestingly, HgCl2, bromoethanesulfonic acid, and N-ethylmaleimide differentially modified protein and nonprotein thiol levels.     

Analysis of the forms of acetylcholinesterase from adult mouse brain.

The solubilization of 80% of the acetylcholinesterase activity of mouse brain was performed by repeated 2h incubations of homogenates at 37 degrees C in an aqueous medium. Analysis of the soluble extract by gel filtration on Sephadex G-200 showed that up to 80% of the enzyme activity was eluted in a peak which was estimated to consist of molecules of about 74000mol.wt. This peak was called the monomer form of the enzyme. After 3 days at 4 degrees C, the soluble extract was re-analysed and was eluted from the column in four peaks of about 74000, 155000, 360000 and 720000 mol.wt. Since the total activity of the enzyme in these peaks was the same as that in the predominantly monomer elution profile of fresh enzyme, we concluded that the monomer had aggregated, possibly into dimers, tetramers and octomers. Extracts of the enzyme were analysed by polyacrylamide-gel electrophoresis and the resulting multiple bands of enzyme activity on gels were shown to separate according to their molecular sizes, that is by molecular sieving. All these forms had similar susceptibilities to the inhibitors eserine, tetra-isopropyl pyrophosphoramide and compound BW 284c51 [1,5-bis-(4-allyldimethylammoniumphenyl)pentan-3-one dibromide]. Thus the forms of the enzyme in mouse brain which can be detected by gel filtration and polyacrylamide-gel electrophoresis may all be related to a single low-molecular-weight form which aggregates during storage. This supports similar suggestions made for the enzyme in other locations.     

Observations on the electric organ discharge of two skate species (Chondrichthyes: Rajidae) and its relationship to behaviour

Synopsis The electric organ discharge (EOD) of the little skate,Raja erinacea and winter skate,R. ocellata was recorded both from isolated individuals and from small groups using methods that allowed for the identification of individuals producing EODs. Pulse duration, train lengh, frequency, and pulse patterns are characterized and correlated with behaviour. The two species,R. erinacea andR. ocellata, were found to have characteristically different EOD pulse durations of 70 ms and 217 ms respectively. Isolated skates rarely discharged whereas groups of skates were found to discharge regularly. The EOD was evoked by tactile prodding, physical contact with other skates and electrical stimulation. Skates also discharged reflexively in response to an artificially induced head-positive DC stimulus, sine wave and monopolar square pulses. During approach and contact, skates responded to each other with interacting EOD displays. EOD interaction and pulse duration differences between other species suggest a possible intra-specific communication function of the EOD inRaja.     

The localization and synthesis of some collagen types in developing mouse embryos.

The location of type IV (basement membrane)collagen in early post-implantation mouse embryos was examined by immunoperoxidase reactions using a specific immunoglobulin raised against mouse lens capsule collagen. Reaction was positive in the earliest embryos studied--on the fifth day of gestation (the day of detection of the copulation plug is the first day). It was found only in the primitive endoderm adjacent to the blastocoelic cavity. Subsequently in development, strong staining reactions were found in the parietal endoderm, Reichert's membrane and an acellular layer which separates the visceral endoderm of the egg cylinder from the ectoderm. In tenth to eighteenth day visceral yolk sacs, the mesodermal portion was stained, which is consistent with the presence of basement membranes around blood vessels. The endodermal portion of the visceral yolk sac did not react, while small amounts were found in the amnion. By incubation of various embryonic tissues with tritiated amino acids, purification of the biosynthesized secreted collagens and their partial characterization, the differential expression of several collagen genes was detected. Identification of collagen types was made by: reaction with specific antibodies to type I and IV collagens; electrophoretic mobility; sensitivity to reduction and to collagenase; analysis of the proportions of 3-hydroxyproline, 4-hydroxyproline and hydroxylysine; and CNBr peptides. In agreement with the data of Minor et al. (1976a) for the rat, mouse parietal endoderm synthesizes large amounts of type IV collagen. In contrast to their findings, however, the 165,000 molecular weight polypeptide is not converted to one of 100,000 after reduction, alkylation and repepsinization (Dehm and Kefalides, 1978). The endoderm of the visceral yolk sac was shown to be synthesizing primarily type I collagen, while the mesoderm layer of this membrane synthesized both type I and IV collagens. Little or no type IV collagen synthesis was detected in the endoderm of the visceral yolk sac. If it is correct that the visceral endoderm of the early embryo makes a major contribution to the formation of the endoderm portion of the visceral yolk sac, then it is clear that a switch in collagen gene expression must occur as it does so.     

Extracellular Polysaccharide of Erwinia amylovora: a Correlation with Virulence

The extracellular polysaccharides produced as slime or capsule layers by bacterial pathogens of animals and plants have been often implicated as factors essential to pathogenesis. In the present study, virulence of the plant pathogen Erwinia amylovora was correlated with the ability to produce extracellular polysaccharide (EPS). EPS production by a series of field isolates and bacterio-phage-resistant mutants differing in the extent to which they cause symptoms in host tissues was examined by quantitation with a modified Laurell rocket immunoelectrophoresis assay. The amount of EPS produced as an easily removed capsular layer or slime on solid nutrient agar approximated the capacity to exhibit symptoms in host inoculation tests. Features common to the virulent isolates are mucoid colony morphology, sensitivity to EPS-specific bacteriophages [S3 and PEal(h)], and ability to produce a characteristic EPS. Mutants selected for resistance to S3 or nonmucoid colony morphology are deficient in EPS production and have lost the ability to multiply in host tissue and cause symptoms. We conclude that EPS may be directly involved in symptom expression and provide a function essential to the growth of the pathogen in host tissues.     

The Life-Cycle of Chlorine, Part I: Chlorine Production and the Chlorine-Mercury Connection

Chlorine is an important industrial chemical. Not only is it a component of many important products, it is also needed for many chemical manufacturing processes, even where it does not appear in the final product. But a number of chlorine chemicals, especially organochlorines, are toxic, carcinogenic, tentogenic or otherwise potentially disturbing to the environment. For this reason, some environmentalists—notably Greenpeace-have advocated a ban, not just on some products but on all uses of elemental chlorine. The chemical industry is taking this threat seriously and mounting a vigorous defense. But the debate so far is not illuminating the issues effectively, because both sides are selectively using questionable and unverifiable data.
The scientific uncertainties are not really the problem. Rather, data in the public domain and accessible to environmentalists and even regulatory authorities are of very poor qualrty. Because of industry secrecy much crucial inforrnation is unavailable and some of what is available is misleading or wrong. The dual purposes of this article, and the ones that follow, are (I) to elucidate the information requirements for an adequate life-cycle analysis of chlorine and its uses and (2) to indicate how and where the use of massbalance methodology can help identify errors and fill in gaps.
The present article deals with electrolytic chlorine produdion and mercury flows arising from chlorine production. Subsequent articles deal with conversion processes and losses and further chemical industry uses of chlorine, major end uses of chlorine and chlorine chemicals, and persistent organochlorine pollutants.     

Trapping and sex pheromone-mediated flight and landing behaviour of maleCtenopseustis obliquana

A sex pheromone-baited delta trap was found to be inefficient at eliciting landing and entering of the trap by maleCtenopseustis obliquana. The inefficiency of the delta trap related to turbulence altering the pheromone plume and the concomitant effect on the flight manoeuvres of male moths. In the wind tunnel, high proportions of males flew upwind and landed on the sides, outside, of the trap, but only a relatively small proportion of these males entered the trap and contacted the sticky surface. When males approached the delta trap, they tended to fly in wide zigzags (i.e., large inter-track reversal distances) and at an altitude near the top of the trap, where the trap was relatively narrow in width (compared to the bottom). Thus, these flight manoeuvres largely precluded males from entering the trap. Greater numbers of male moths entered the trap when: (i) the front barriers of the delta trap were removed, (ii) pheromone dosage was increased to 300 μg, and (iii) the trap design was changed to a rectangular one. The first two changes appeared to influence the flight manoeuvres of males (who appeared to fly with narrower inter-track reversal distances), while the third change apparently did not affect the glight manoeuvres of males, but rather allowed more males to enter the trap because of the greater area of the entrance. The low trap catches of maleC. obliquana in the field are also a consequence of the glue which is currently used. After contact with this glue most males are able to escape, flying off the sticky surface and losing contact with the pheromone. A field trial found that delta traps with another glue caught more than three times the number of males of the related tortricid moth,Epiphyas postvittana, than delta traps with the currently used glue.