Antimicrobial Properties of Oleuropein and Products of Its Hydrolysis from Green Olives

Oleuropein, the bitter glucoside in green olives, and products of its hydrolysis were tested for antibacterial action against certain species of lactic acid bacteria involved in the brine fermentation of olives. Oleuropein was not inhibitory, but two of its hydrolysis products, the aglycone and elenolic acid, inhibited growth of the four species of lactic acid bacteria tested. Another hydrolysis product, beta-3,4-dihydroxyphenylethyl alcohol, was not inhibitory. The aglycone of oleuropein and elenolic acid were much more inhibitory when the broth medium contained 5% NaCl; 150 mug of either compound per ml prevented growth of Lactobacillus plantarum. A crude extract of oleuropein, tested by paper disk bioassay, was inhibitory to 3 of 17 species of bacteria screened, none of which were lactic acid bacteria. The acid hydrolysate of the extract was inhibitory to 11 of the bacteria, which included four species of lactic acid bacteria and other gram-positive and gram-negative species. Neither crude preparation was inhibitory to growth of the seven species of yeasts tested. A possible explanation is given for the previously reported observation that heating (3 min, 74 C) olives prior to brining renders them more fermentable by lactic acid bacteria. Results of a brining experiment indicated that oleuropein is degraded to antibacterial compounds when unheated olives are brined.     

The release of proteinase inhibitors from legume seeds during germination

The seeds of twelve common species of legumes were examined for the release of proteinase inhibitor activity during germination. All species released inhibitory activity against bovine trypsin (EC 3.4.21.4), ranging from 1.0 unit per g dry wt. of seed in 24 hr for soybean (Glycine max), to 0.07 unit per g for broad beans (Vicia faba) and sugar pod peas (Pisum sativum). This release corresponds to approximately 1–13 % of the total trypsin inhibitory activity of the seed, with lentils (Lens culinaris) releasing the greatest percentage, and the scarlet runner bean (Phaseolus coccineus) the least. In most species the amount of inhibitor released increases until 24–48 hr of germination, and then remains roughly the same or decreases slightly by 72 hr of germination. Five species of legumes were also examined for the release of inhibitory activity against bovine chymotrypsin (EC 3.4.21.1). In each case chymotryptic inhibitory activity was released in a manner similar to the trypsin inhibitor.     

Studies of ribosomes of yeast species: Susceptibility to inhibitors of protein synthesis in vivo and in vitro

Summary The susceptibility of cells from various species of Saccharomyces and Kluyveromyces was tested against different types of protein synthesis inhibitors. Minimal inhibitory concentrations were determined for each yeast species and the sensitivity of their ribosomes in cell-free extracts was tested. Two aminoglycosides, paromomycin and hygromycin B were assayed for capacity to stimulate translation errors with ribosomes of yeast species showing different minimal inhibitory concentrations in vivo. In many cases a correlation exists between natural and in vitro resistance suggesting that some natural antibiotic resistances are ribosomal.     

Screening of angiotensin-converting enzyme inhibitory activities in microalgae

As part of the investigation on useful constituents in microalgae, we searched for angiotensin converting enzyme inhibitory activities in water-soluble and fat-soluble fractions of sixteen species and strains. Water-soluble fractions of eleven species and fat-soluble fractions of eight species showed inhibitory activities. In particular, the water-soluble fractions of the freshwater cyanophytesMicrocystis spp. showed inhibition at a concentration as low as 0.25 mg ml⁻¹, and that of the halotolerant chlorophyteDunaliella bardawil showed moderate inhibition. The active principles were suggested to be low molecular peptides.     

Cysteine proteinase inhibitors of the canine intervertebral disc

Several species of cysteine proteinase inhibitors have been demonstrated in the greyhound intervertebral disk which were resolved four species (M_r 15 8000, 16 600, 17 200 and 17 800) by gelatin-SDS-polyacrylamide gel electrophoresis. Reductive alkylation did not affect their inhibitory capability not their electrophoretic migration on gelatin-SDS-polyacrylamide gel electrophoresis. The cysteine proteinase inhibitors from the nucleus pulposus and annulus fibrosus were identical as assessed by the aforementioned criteria, although the level in the nucleus was found to be higher than that in the annulus. Ion-exchange chromatography demonstrated distinct acidic and basic forms of the disc cysteine proteinase inhibitor. The latter species was the most abundant and its M_r was determined to be 16 900 by gelatin-SDS-polyacrylamide gel electrophoresis. Both forms were shown to be strongly inhibitory against the cysteine proteinases. papain and ficin, but were less strongly inhibitory against cathepsin B (EC 3.4.22.1). Presumably these disc cysteine proteinase finhibitors play a regulatory role in the metabolism of proteoglycans and collagen by endogenous cysteine proteinases.     

Enhanced species-specific chemical control of harmful and non-harmful algal bloom species by the thiazolidinedione derivative TD49

Culture experiments involving 23 algae strains were conducted to evaluate the algicidal effects of a newly developed algicidal thiazolidinedione (TD) derivative (TD49) on non-harmful and harmful algal bloom (HAB) species. We also assessed the effect of various concentrations of TD49 on various growth phases (lag, logarithmic, and stationary) of the harmful algae Heterocapsa circularisquama (Dinophyceae) and Heterosigma akashiwo (Raphidophyceae; hereafter, Heterosigma) and the non-harmful diatoms Skeletonema costatum and Chaetoceros didymus. The inhibitory ratios (%) for H. circularisquama and Heterosigma at 2.0 μM TD49 were significantly higher than those at other concentrations, and the inhibitory ratio varied depending on growth phase and species as follows: logarithmic?≥?stationary?>?lag phase for H. circularisquama and logarithmic?≥?lag?>?stationary phase for Heterosigma. Although the inhibitory ratios for C. didymus were similar to those for the two harmful algae (H. circularisquama and Heterosigma), inhibitory effects on S. costatum were not apparent at >2.0 μM in any growth phase. The algicidal activity of TD49 on the harmful and non-harmful algae was as follows: unarmored HAB species?>?armored HAB species?>?diatom species?>?cryptophyte species. TD49 was algicidal to most HABs but had a little inhibitory effect on some non-harmful algae, implying that TD49 has selective algicidal activity. Our results indicate that TD49 is potentially of use in the control of HAB species within semi-enclosed bays.     

Physical and chemical effects of litter on plant establishment in semi-natural grasslands

A field experiment was conducted in a semi-natural grassland to study the interspecific variation in the effect of litter on seedling emergence and establishment and separate physical from chemical effects. Seeds of seven forb species were sown in plots subjected to either litter amendment (0, 400 or 900 g m⁻²) or water extracts of litter (corresponding to 400 and 900 g litter m⁻²). In addition, an extract was treated with activated carbon to estimate the possible effects of secondary chemical compounds. The response to plant litter differed amongst species: negative, neutral and positive responses were observed. Anthriscus sylvestris was the only species with a strong positive response to litter. We found no consistent relation between seed size and response to plant litter. Physical effects of litter were generally stronger than chemical effects. However, water extract of litter inhibited emergence in three species. Activated carbon removed the negative effect of the litter extract, which suggests that the effect was caused by an inhibitory chemical compound rather than by increased competition in response to nutrients added via the extract. The balance between facilitative and inhibitory effects of litter depended on species identity and litter quantity. Facilitative effects dominated at low and intermediate quantities of litter, and inhibitory effects at high litter quantities. One species, Campanula rotundifolia, showed a switch from positive to negative responses with increasing quantities of litter. However, we found no general threshold for litter quantity valid across species.     

Inhibition of the growth of two blue-green algae species (Microsystis aruginosa and Anabaena spiroides) by acidification treatments using carbon dioxide

The effect of pH adjusted by aeration with carbon dioxide (CO₂) on the growth of two species of blue-green algae, Microcystis aeruginosa and Anabaena spiroides, was investigated. Three conditions (pH 5.5, 6.0 and 6.5) were found to have significant inhibitory effects on the growth of the two algae species when acidification treatment was conducted during the logarithmic phase. Differences in the inhibition effect of acidification existed between the two species algae. The tolerance of M. aeruginosa to these conditions was also investigated. The results indicated that M. aeruginosa was inhibited significantly, but not dead at pH 6.5, whereas death occurred at pH 5.5 and 6.0. The greatest inhibitory effect of acidification treatment conducted during the stable breeding phase of M. aeruginosa occurred at pH 5.5, while no inhibitory effect was found at pH 6.5.     

Design and synthesis of tacrine-ferulic acid hybrids as multi-potent anti-Alzheimer drug candidates

Five tacrine–ferulic acid hybrids (6a–e) were designed and synthesized as multi-potent anti-Alzheimer drug candidates. All target compounds have better acetylcholinesterase inhibitory activity and comparable butyrylcholinesterase inhibitory activity in relation to tacrine. Interestingly, 6d showed a reversible and non-competitive inhibitory action for acetylcholinesterase indicating interaction with the peripheral anionic site, whereas a reversible but competitive inhibitory action for butyrylcholinesterase. The antioxidant study revealed that four target compounds have, compared to Trolox, high ability to absorb reactive oxygen species.     

The induction of suppressor T cells by lipopolysaccharide in human peripheral blood lymphocyte cultures in the presence of fetal calf serum

Alveolar macrophages (AM) were collected by repeated endobronchial lavage from mice, rats, guinea pigs, and rabbits, and titrated into cultures of mitogen-stimulated syngeneic or autochthonous lymphocytes. Significant species differences were detected in regard to AM activity in the cultures. AM from guinea pigs and mice stimulated PHA-induced lymphoproliferation, while those from rats and rabbits were inhibitory; blood or peritoneal macrophages were not inhibitory in any of the species examined.     

Evaluation of four grasses for use in phytoremediation of Cs-contaminated arid land soil

Although residue management seems a key factor in residue-mediated weed suppression, very few studies have systematically compared the influence of different residue management strategies on the establishment of crop and weed species. We evaluated the effect of several methods of pre-treatment and placement of winter rye (Secale cereale L.) and winter oilseed rape (Brassica napus L.) residue on seedling emergence under field conditions. For both species two cultivars, differing in allelochemical content, were used. Residues incorporated in the upper soil layer exerted a large inhibitory effect on the establishment of the relatively early emerging lettuce (Lactuca sativa L.) and spinach (Spinacia oleracea L.) seedlings, whereas the inhibitory effect on the slightly later emerging Stellaria media L. seedlings was variable, and often a stimulatory effect on the very late emerging Chenopodium album L. seedlings was observed. Differences between cover crop cultivars were minor. For winter oilseed rape residue, pre-treatment strongly affected the time-course of residue-mediated effects. Finely ground residues were only inhibitory to seedling establishment during the first two to three weeks, whereas cut residues became inhibitory after this period. For winter rye, residue placement was most important. Residue incorporation gave variable results, whereas placement of winter rye residue on top of the soil inhibited the emergence of all receptor species. In conclusion, the optimal residue management strategy for weed suppression depends both on the cover crop species used and the target weed species.     

COMPARATIVE SENSITIVITY OF THREE SPECIES OF CHLAMYDOMONAS TO ANALOGS OF METABOLITES1,2

Twenty-five analogs of metabolites were tested for their ability to inhibit the growth of Chlamydomonas eugametos, C. moewusii, and C. reinhardii. Eleven of the tested analogs were inhibitory to 1 or more species, but only 3 compounds were inhibitory to all 3.     

Comparative study of inhibitory specificity of liver monoamine oxidase in frogs <Emphasis Type="Italic">Rana ridibunda</Emphasis> and <Emphasis Type="Italic">Rana temporaria</Emphasis>

A comparative enzymological investigation of inhibitory specificity of the liver monoamine oxidases (MAO) from the two frog species, lake frog Rana ridibunda and grass frog Rana temporaria, revealed certain interspecies similarities and distinctions of this enzyme. The anti-monoamine oxidase effect of five derivatives of acridine, three derivatives of phenothiazine and one derivative of xanthene (pyronine G) was comparatively analyzed. The tested six-membered tricyclic compounds were shown to exert an irreversible inhibitory effect on the enzyme from both biological sources, displaying the same substrate deamination specificity. Thus, the rate of interaction of acridine and phenothiazine derivatives with the MAO active center in both frog species was considerably higher when activity was determined using noradrenaline versus N-methylhistamine, while that of pyronine G—when activity was determined using N-methylhistamine versus noradrenaline. Interspecies quantitative differences were found in the inhibitory efficacy and degree of selectivity of the tested tricyclic compounds, indicative of the differences in catalytic properties of liver MAO at the interspecies level in the representatives of the genus Rana, family Ranidae. The data of substratespecific inhibitory analysis provide indirect evidence of the existence of two molecular MAO forms in the liver of the studied frog species.     

Protective effects of luteolin-7-O-β-D-glucuronide methyl ester from the ethyl acetate fraction of Lycopi Herba against pro-oxidant reactive species and low-density lipoprotein peroxidation

In this study the potent scavenging activity of “Lycopi Herba” (LH) extract was studied using the following: evaluation of the total phenolics, measuring the antioxidant activity by Trolox equivalent antioxidant concentration, measuring the scavenging effects on reactive oxygen species, on reactive nitrogen species, and measuring the inhibitory effect on Cu²⁺ induced human low-density lipoprotein oxidation in vitro. The ethyl acetate fraction from the LH extracts were found to have a potent scavenging activity against all of the reactive species tested, as well as an inhibitory effect on LDL oxidation. Therefore, we isolated and identified luteolin-7-O-β-D-glucuronide methyl ester as the major compound from the ethyl acetate fraction of LH and their antioxidant activities were evaluated.     

Discovery and structure-activity relationship of imidazolinylindole derivatives as kallikrein 7 inhibitors

A series of imidazolinylindole derivatives were discovered as novel kallikrein 7 (KLK7, stratum corneum chymotryptic enzyme) inhibitors. Structure-activity relationship (SAR) studies led to the identification of potent human KLK7 inhibitors. By further modification of the benzenesulfonyl moiety to overcome species differences in inhibitory activity, potent inhibitors against both human and mouse KLK7 were identified. Furthermore, the complex structure of 25 with mouse KLK7 could explain the SAR and the cause of the species differences in inhibitory activity.     

ALLELOPATHIC EFFECTS OF ANDROPOGON VIRGINICUS AND ITS PERSISTENCE IN OLD FIELDS

Aqueous extracts of fresh roots and shoots of Andropogon virginicus (broomsedge) were found to be inhibitory to the growth of seedlings of Amaranthus palmeri, Bromus japonicus, Aristida oligantha, and Andropogon scoparius. The first two species are often important in the pioneer stage of old-field succession in eastern Oklahoma, Aristida is prominent in the second stage, and Andropogon scoparius is important later in succession including the climax Quercus stellata–Quercus marilandica savanna. Sterile dilute extracts of roots and shoots of broomsedge were inhibitory to two test species of Azotobacter, a free living nitrogen fixer, and to two species of Rhizobium, a symbiotic nitrogen fixer. Small amounts of decaying shoots of broomsedge (1 g per 454 g of soil) were very inhibitory to the growth of the four test species listed above and to Amaranthus retroflexus, another species often important in the first stage of succession. Similar amounts of decaying material in soil also significantly inhibited growth and nodulation of the two most important species of legumes in old-field succession in eastern Oklahoma, Lespedeza stipulacea and Trifolium repens. Broomsedge is known to compete vigorously and grow well on soils of low fertility, so the inhibition of nodulation of legumes could help keep the nitrogen supply low and give broomsedge a selective advantage in competition over species that have higher nitrogen requirements. The combined interference of broomsedge against other species resulting from competition and allelopathy could help explain why it invades old fields in 3–5 yr after abandonment from cultivation and remains so long in almost pure stands.     

Production of bacteriocins by different enterococcal isolates

Bacteriocins produced by ruminal as well as environmental isolates were found to be heat-stable antimicrobial substances with a broad inhibitory spectrum (including Gramnegative species and sanitary-important species). The exponential phase of growth and pH 4–7 were optimal for their production. After purification, some of them were sequenced and specified.     

Methanogenic inhibition by arsenic compounds

The acute acetoclastic methanogenic inhibition of several inorganic and organic arsenicals was assayed. Trivalent species, i.e., methylarsonous acid and arsenite, were highly inhibitory, with 50% inhibitory concentrations of 9.1 and 15.0 microM, respectively, whereas pentavalent species were generally nontoxic. The nitrophenylarsonate derivate, roxarsone, displayed moderate toxicity.     

Odour sensitivity of antennal olfactory cells underlying grooved pegs of Anopheles gambiae s.s. and An. quadriannulatus

In female mosquitoes of the anthropophilic species Anopheles gambiae Giles s.s. and the zoophilic An. quadriannulatus Theobald single sensillum recordings from grooved pegs were made. In both species, the majority of these sensilla responded to ammonium hydroxide, butylamine and propanoic acid, whereas a smaller part responded to acetone. Lactic acid, butanone, 3-methyl phenol and 1-octen-3-ol evoked responses in a minority of grooved pegs only. In An. gambiae these four substances evoked either excitatory or inhibitory responses. In An. quadriannulatus excitatory and inhibitory responses were only found on stimulation with lactic acid; butanone, 3-methyl phenol and 1-octen-3-ol only evoked inhibition in the pegs of this species. More than half of the grooved pegs responded to water vapour with an increase in spike frequency. As opposed to this, in some pegs inhibitory responses were found upon stimulation with vapour of low humidity. This suggests that grooved pegs may play a role in humidity perception in Anopheles. Dose-response relations were investigated for cells excited by ammonium hydroxide, butylamine and propanoic acid. Excitatory responses to these three substances were dose-dependent. No significant differences were found between the dose-response curves of the two species. It is concluded that in both species the host odours tested are not perceived by specialist cells. Combined information from generalist cells may provide a detailed `odour profile' of the host.     

THE ECOLOGICAL IMPACT OF ALLELOPATHY IN AILANTHUS ALTISSIMA (SIMAROUBACEAE)

Compounds inhibitory to the growth of neighboring plant species were found in significant concentrations in the leaves and stems of young Ailanthus altissima ramets. The surrounding soil also contained appreciable concentrations of similarly acting toxins. Individuals of neighboring plant species have either incorporated active portions of inhibitory compounds or responded to Ailanthus by producing growth-inhibiting substances. Under greenhouse conditions, individuals of neighboring plant species previously unexposed to Ailanthus in the field were found to be more susceptible to the Ailanthus toxins than individuals previously exposed. Moreover, seeds produced by unexposed populations were also more susceptible to Ailanthus toxins than seeds produced by previously exposed populations. These differences demonstrated that the allelochemicals of Ailanthus altissima exhibited a measurable impact upon neighboring plant species. Since the progeny of these populations displayed a differential response to Ailanthus toxin, this phenotypic difference between the two populations may have a heritable basis.