Lethal activity

Actinia cari. When an extract of the tentacles of this species was subjected to gel nitration, a single protein peak having hemolytic and lethal activities was obtained. Further fractionation by CM-cellulose ion-exchange chromatography yielded three well separated peaks (CTl, Cmi, Cmil) which appeared to be similar in biological activity (14). 

An alternative strategy is for the microorganism to kill the phagocyte. This can be achieved by the production of leucocidins (e.g. staphylococci, streptococci) which promote the discharge of lysosomal substances into the cytoplasm of the phagocyte rather than into the vacuole, thus directing the phagocyte s lethal activity towards itself. 

The lethal activity of the isobutylamides on C. pipiens is shown in Table II. The amides were dissolved in 0.1% acetone in distilled water to give concentrations of 1-20 ppm. Third-instar C. pipiens were transferred (5 larvae/10 ml test solution) into 1 oz. plastic cups using a 1 x 1-inch circle of ordinary window screen. Each treatment was replicated 4 times and the minimum concentration of each compound which caused 100% mortality (LDioo) within 48 h at 25 C and 16L/8D photoperiod was determined. In a result similar to that found with the artificial diet bioassay with lepidopterous larvae, pellitorine proved to be the most toxic of the assayed amides (LDjqq = 5 ppm). 

The lethal activity of the isobutylamides on B. glabratus is shown in Table III. Molluscicidal activity was monitored as described previously.Briefly, snails of uniform sizes (average diameter of the shell 9 mm) were placed 2 snails/ concentration into deionized water solutions containing known concentrations of the isobutylamides. Unlike the relative activities of the isobutylamides on the tested insect species, fagaramide (1 ) and N-isobutyl-2E,4E -octadienamide ( ) were more potent molluscicides than were pellitorine (4) or piperlongumine (2). 

Table III. Lethal activity in ppm) of natural isobutylamides against the snail Biomphalaria glabratus. ...

Kondrltzer et al.,130 n searching for a salt of 2-PAM that would be more soluble than 2-PAM I in water, made a number of other salts. Most of these were considerably more soluble in water than 2-PAM I. One of the most soluble was the lactate, with a solubility of 1 g/ml. Unfortunately, this salt was found to be quite unstable in aqueous solution with respect to heat. I was less soluble in water than the lactate, but more than 13 times as soluble as the iodide. Furthermore, solutions of I at a pH of 3.5-4.3 could be autoclaved at 120°C for 15 min with only a 4% loss. Solutions of this salt stored at 50-70°C for 1-3 mo contained at least 78% of the original oxime and no more than 0.1% of hydrogen cyanide. When the aged solutions were examined for lethality to experimental animals, their lethal activities were exactly those expected on the basis of their oxime concent rat ions. 

Pesticides and their metabolites are one of the most important classes of environmental pollutants, because, as their name indicates, they are chemicals designed to kill pests and, therefore, must possess inherent lethal activity. The high levels of pesticides applied to the environment, estimated at 3 million tons per year worldwide in the middle of 1980s, suggest the potential for significant exposures of human populations (25). 

Remarkable is the fact that 73a and 73b, showing the greatest difference in sub-lethal activity and toxicity, exhibit the same action under invitro conditions. Both compounds were found to be antagonists of the muscarinic activity of acetylcholine and carbachol71. The dose-response curves of acetylcholine antagonized by 73a and 73b were identical within experimental error. 

Oike, H., Matsuoka, R., Tashiro, Y., Hirayama, M., Tamura, Z., and Yamazaki, S., Effect of Bifidobacterium-monoassociation and feeding of fructooligosaccharides on lethal activity of enterohemorrhagic Escherichia coli 0157 in germ-free mice, Bifidobacteria Microflora, 18, 101-109, 1999. 

Yamazaki, S., Kamimura, H., Momose, H., Kawashima, T., and Ueda, K., Protective effect of bifidobacteria non-association against lethal activities of Escherichia coli, Bifidobacteria Microflora, 1,55-64, 1982. 

Magnesium silicate is used against juvenile and adult store product pests, exerting its lethal activity predominantly on juvenile and adult forms by sorption of the cuticular lipid layer, thus causing dehydration of the insects. 

The information on the lethal activities of the members of this group of esters Is sparse. Even when reports dealing with lethality according to their titles were furnished by the Board on Toxicology and Environmental Health Hazards, the texts provided were brief and uninformative. An example Is a report (233) entitled A Review of the Pharmacology and Toxicology of CAR 301,060. This compound Is the ester of phenylcyclopentylglycollc acid and 2-methyl-3-qulnuclldlnol. 

Table 1-4 contains the Information that could be obtained on the single-dose lethal activities of the two substances In this group, bensetlmlde and meplperphenldol. Information on the toxlcltles of these compounds was supplied by Janssen Pharmaceutics and Sharp and Dohme Institute for Medical Research, respectively. Benzetlmlde Is 2-(I benzy1-4-plperldyl)-2-phenylglutarlmlde, and meplperphenldol Is l-(3-hydroxy-4-phenyl-5-me thyIhexy1)-l-methyIplperldlnlum bromide. 

Plot the time-to-death (30 to 120 min) against the toxin doses (5 to 100 ipLDso/ml) both in logarithms this results in a linear relationship between them. From this curve, the time-to-death in min after intravenous injection of a toxin sample can be converted into the lethal activity (ipLDso). 

By these purification procedures, 1-3 mg of component I and 20-40 mg of component II are recovered from 4 I of culture of C. botulinum type C strain 92-13. The mixture of untrypsinized component I and trypsinized component II has high lethal activity in mice (specific activity is about 2x10 mouse intraperitoneal 50% lethal doses per mg of protein), although each of these components alone shows very low activity even after trypsinization. The purified components I and II each show one band in SDS-PAGE, and their molecular weights as determined by the electrophoresis are 45kDa and 100 kDa, respectively. 

Figure 1. Essential moiety for lethal activity of formamidines in acarines. Reproduced with permission from Ref. K Copyright 1982, Academic Press.

To explore this further, a demographic study was conducted with chlordimeform, amitraz, and compound 17, which was the most active mite reproduction inhibitor among the nonlethal formamidines (20). Each of the three formamidines caused a reduction in survivorship and fecundity which resulted in a significant decrease in the intrinsic rate of increase of the mite population. In these experiments, amitraz was most potent, chlordimeform was intermediate, and compound 17 was least potent (20). This apparent disparity between the strong activity of chlordimeform and amitraz on mite reproduction at the population level and their weak activity at the individual level can be explained as follows. The effects of amitraz on population growth were due mainly to its lethal activity to the various life stages, and the effects of chlordimeform were due to its lethality to life stages as well as its reduction of fecundity. The activity of compound T7 resulted only from its reduction of fecundity (20). 

Table III. UVA-Medlated Lethal Activity of Alpha-Terthienyl Toward Various Organisms...

Five amides, 50(n=4,6), 55, 5 and 6(n=6), isolated from P. guineense were investigated by Candy and co-workers [10] with respect to their knockdown and lethal activity against adult houseflies, as well as the rates of recovery of M. domestica from the effects of sublethal doses of the amides. As with other insecticides, rapid and potent knockdown activity on topical application of the amides depends, apart from the intrinsic toxicities of the individual compounds, on their ability to penetrate the cuticle and relevant membranes en route to the site of action. Attempts to correlate knockdown activity in the P. guineense amide series with polarity on this basis seemed to show some inconsistencies, perhaps as a result of steric factors [10,102]. The rate of recovery from the effects of sub-lethal doses of insecticides is associated, inter alia, with processes that lead to removal of the toxicant, so that recovery from treatment with Piper amides embodying the methylenedioxyphenyl group, which retards the action of mixed function oxidases, is slower than recovery from the effects of the less stable aliphatic amides. 

Test organism Contact time in minutes Germ count germs/ml Lethal active concentration in ppm PCMC WHS DW ... 

Disinfectant formulations based on OPP take the poor water solubility of OPP into consideration. Anionic surfactants and soaps are used preferably to a limited extent (below the critical micellization concentration) non-ionic surfactants may be used, too. The rule that the microbicidal effect of phenolic compounds is dependent on such factors as the pH of the ready-to-use dilution, degree of contamination/germ count, water hardness and dirt content applies to OPP, too. The bactericidal effect of a standard formulations (SF) containing 10% OPP -f25% sec. alkanesulphonate +20% isopropanol +45% demineralized water is documentated in Table 71 by the lethal active concentrations of OPP (mg/1) for various species of bacteria in dependence of pH, on protein loading and on a high germ count (approx. lO germs per ml solution to be disinfected). 

Test organism Time in minutes Lethal active concentration in mg OPP/1 ... 

Since different types of DNA damage are subjected to cellular recombination repair, recombinationless bacteria are usually more sensitive than the wild type. Agents showing increased lethal activity on Rec in comparison with Rec" cells may have caused cellular DNA damage. Because of the simplicity of the procedures, positive chemicals are very easily selected and pooled even from a great number of samples. The DNA-damaging substances are then examined for specificity of induced mutations in bacterial systems. It has been shown that a majority of the rec-assay-positive chemicals are true mutagens. 

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