Antioxidant and antimicrobial properties of ethanolic extract fromLepista nuda (Bull.) Cooke

Antioxidant capacity and antimicrobial activities ofLepista nuda (Bull.) Cooke extracts obtained with ethanol were investigated. Four complementary test systems, namely DPPH free radical scavenging, β-carotene/linoleic acid systems, total phenolic compounds and total flavonoid concentration, have been used. Linoleic, acid inhibition values ofL. nuda ethanolic extract, BHA and α-to copherol standards were found to be 84.3% 98.9% and 99.2% respectively in the concentration of 160μg/ml. Total flavonoid amount was 8.21 ± 0.56 μg mg^?1 quercetin equivalent while the phenolic compound amount was 48.01 ± 0.29 μg mg^?1 pyrocatechol equivalent in the extract. The antimicrobial activity ofL. nuda extract was testedin vitro by using the agar-well diffusion method. TheL. nuda extract showed antibacterial activity againstMicrococcus flavus, Micrococcus luteus, Bacillus cereus, Yersinia enterocolitica, Staphylococcus aureus, Salmonella enteritidis andEscherichia coli. TheL. nuda extract did not exhibit antican didal activity againstCandida albicans. The extracts could be suitable as antimicrobial and antioxidativeagents in the food industry.     

Reevaluation of Mimosa biuncifera and M. texana (Leguminosae: Mimosoideae)

Mimosa biuncifera, as currently defined in southwestern United States, is shown to comprise two related species,M. biuncifera s. str. andM. texana, distinguished primarily by position of the nodal aculei. Taxonomic synonyms ofM. biuncifera areM. lindheimeri andM. warnockii (the first undisputed, the second provisional);M. texana includesM. wherryana.     

Life cycle and host range of the gall-forming moth,Meskea horor (Lep.: Thyrididae), and its suitability as a biological control agent forSida acuta andS. rhombifolia (Malvaceae)

The life cycle of the moth,Meskea horor Dyar and its host specificity toSida acuta andS. rhombifolia were investigated. Moths emerge early in the morning and are usually inactive during the day. Feeding by the adults in the field was not observed. However, those in the laboratory fed on flowers ofS. acuta, S. rhombifolia andHibiscus sabdariffa, and drank water or dilute honey solution. Eggs are mainly laid on the underside of leaves. Larvae ofM. horor form galls in the stems ofS. acuta andS. rhombifolia which retard plant growth and flowering. Pupation occurs within the gall. The development time from egg to adult was 192 days and the adults lived for 11 to 14 days. Forty-eight plant species were tested to determine the host range ofM. horor. Adults emerged from seven species of plants in the family Malvaceae and larvae formed galls but died before pupating on a further 17 species.M. horor is considered to have too broad a host range to be used as a biological control agent forS. acuta andS. rhombifolia.     

Systematic relationships in the white-rayed species of Melampodium (Compositae)

The white-rayed species complex ofMelampodium has been treated by various authors as containing one, two, or three species. A re-evaluation of the taxa in this complex by use of Chromatographic profiles of methanolic leaf extracts from numerous populations over the range of the group has revealed three distinct patterns which, along with morphological and ecological data, provide support for the recognition of three species within the group. Distributional analysis of previously and newly reported chromosome counts of 157 plants in 99 populations shows tetraploid races ofn = 20 in bothM. leucanthum var.leucanthum andM. cinereum var.cinereum to be located primarily in central and south central Texas but locally intermixed with diploid races. Interpretation of morphology, meiotic configurations, and chemical profiles confirms that these cytotypes are autopolyploid in origin and should not be given formal recognition. All data are used to interpret evolutionary relationships, and it is believed thatM. leucanthum var.argopkyllum may closely resemble the progenitor of the entire complex.     

Extraction and preliminary characterizaion of a mycobacteriolytic preparation (stazyme) from aStaphylococcus strain: mycobactericidal activity and its use in rapid extraction of mycobacterial DNA

The clear culture filtrate from 1-L culture of a laboratory contaminant ofStaphylococcus (coagulase^– strain, designated Clavelis) was filtered, concentrated, dialyzed, and the proteins were precipitated. The precipitate was washed, concentrated, and aliquoted (about 4 mg of total proteins/ml, designated as Stazyme). The crude preparation was subjected to gel filtration on Sephadex G-75, and the fractions were screened for their lytic ability againstMycobacterium smegmatis. Native proteins in the stazyme were electrophoretically separated, electroeluted, and their lytic activity againstM. smegmatis was compared with parallel controls (partially purified proteins extracted from the same quantity of the uninoculated bacterial growth medium). Only stazyme preparations caused significant growth inhibition ofM. smegmatis, M. chelonae, M. xenopi, M. tuberculosis, andM. kansasii. Stazyme essentially possessed a lytic activity measured with purifiedM. smegmatis andMicrococcus lysodeikticus cell walls and showed high bactericidal activity againstM. smegmatis, M. chelonae, andM. tuberculosis. It was also able to rapidly lyse intactM. smegmatis organisms, permitting significant yield of mycobacterial DNA.     

Isolation ofVibrio parahaemolyticus andVibrio cholerae (Non-O1 and O139) from moribund shrimp (Penaeus monodon) and experimental challenge study against post larvae and juveniles

Outbreak ofVibrio infection was reported from a shrimp farm near Chennai, south India. Both green and yellowVibrio were isolated from disease outbreak ofPenaeus monodon (Milne Edwards) culture farm and biochemically confirmed asVibrio parahaemolyticus andVibrio cholerae. Randomly selectedV. parahaemolyticus (VP1) andV. cholerae (VC1) were reconfirmed by partial 16S rRNA gene analysis. Both were tested against post larvae and juveniles ofP. monodon by bath challenge test and intramuscular injection respectively. The study revealed that VP1 is more virulent than VC1 isolated from same source againstP. monodon post larvae and juveniles. Phylogenetic tree based on comparison of partial 16S rRNA gene analysis revealed close relationship of VP1 with other shrimp pathogens likeVibrio harveyi andVibrio alginolyticus. There might be some close relationship for disease development among all these strains.     

Aspidosperma (Apocynaceae) plant cytotoxicity and activity towards malaria parasites. Part II: experimental studies with Aspidosperma ramiflorum in vivo and in vitro

Several species of Aspidosperma plants are used to treat diseases in the tropics, including Aspidosperma ramiflorum, which acts against leishmaniasis, an activity that is experimentally confirmed. The species, known as guatambu-yellow, yellow peroba, coffee-peroba andmatiambu, grows in the Atlantic Forest of Brazil in the South to the Southeast regions. Through a guided biofractionation of A. ramiflorum extracts, the plant activity against Plasmodium falciparum was evaluated in vitro for toxicity towards human hepatoma G2 cells, normal monkey kidney cells and nonimmortalised human monocytes isolated from peripheral blood. Six of the seven extracts tested were active at low doses (half-maximal drug inhibitory concentration < 3.8 µg/mL); the aqueous extract was inactive. Overall, the plant extracts and the purified compounds displayed low toxicity in vitro. A nonsoluble extract fraction and one purified alkaloid isositsirikine (compound 5) displayed high selectivity indexes (SI) (= 56 and 113, respectively), whereas compounds 2 and 3 were toxic (SI < 10). The structure, activity and low toxicity of isositsirikine in vitro are described here for the first time in A. ramiflorum, but only the neutral and precipitate plant fractions were tested for activity, which caused up to 53% parasitaemia inhibition of Plasmodium berghei in mice with blood-induced malaria. This plant species is likely to be useful in the further development of an antimalarial drug, but its pharmacological evaluation is still required.     

Functional responses of two chrysopid predators feeding onHelicoverpa armigera (lep.: noctuidae) and aphis gossypii (hom.: aphididae)

Predation onHelicoverpa armigera (Hubner) eggs andAphis gossypii (Glover) nymphs by 3rd instar larvae ofMallada desjardinsi (Navas) andChrysoperla congrua (Walker) was studied under laboratory conditions. Single predators that had been starved for 24 hours were isolated for 1 hour in 9 cm Petri dishes containing prey at densities of 5, 10, 15, 20 and 25 per dish. A type II functional response model gave a satisfactory fit to the data in case ofM. desiardinsi preying onH. armigera. However, with C.congrua, a type III model gave a slightly better fit. ForA. gossypii, functional responses of both predators did not differ from type II, withM. desjardinsi showing a significantly lower search rate and shorter handling time thanC. congrua. Implications of these findings are discussed     

A taxonomic revision of granite outcrop species of Minuartia (Arenaria)

Minuartia glabra (Michx.) Mattfeld andM. uniflora (Walt.) Mattfeld are proposed as the proper taxonomic treatments ofArenaria glabra Michx. [A. groenlandica var.glabra (Michx.) Fern.] andArenaria uniflora (Walt.) Muhl. respectively. A previously unreported species,Minuartia alabamensis is described as new.Minuartia alabamensis andM. uniflora axe more closely related to one another than either is toM. glabra. Minuartia glabra is postulated to be derived from the Arcto-Tertiary flora, which invaded the Piedmont from the Appalachian Highlands.Minuartia alabamensis andM. uniflora are thought to be relicts or species derived from the Madro-Tertiary flora, which invaded the Piedmont from the Southwestern United States and Mexican Highlands.     

Efficiency of four heteroptera as predators ofAphis gossypii andMacrosiphum euphorbiae (Hom.: Aphididae)

Predation rate and nymphal development time were determined for four predatory bugs (Dicyphus tamaninii Wagner andMacrolophus caliginosus Wagner [Het.:Miridae],Orius laevigatus (Fieber) andO. majusculus (Reuter) [Het.:Anthocoridae], on cucumber withAphis gossypii Glover (Hom.:APhididae) as prey and for both mirids also on tomato withMacrosiphum euphorbiae (Thomas) as prey. All four predator species were able to achieve adulthood feeding on both aphids. The developmental period ofD. tamaninii nymphs was the longest and the shortest was forO. majusculus. During nymphal developmentD. tamaninii consumed greater numbers of both aphids thanM. caliginosus, whileOrius’ consumption ofA. gossypii was intermediate. Average daily predation was higher forD. tamaninii than forM. caliginosus, but was not different from bothOrius species. FemaleD. tamaninii exhibited a typical type-II functional response when preying on varying densities ofA. gossypii nymphs.     

SEM observations on seeds ofStriga spp. andBuchnera americana (Scrophulariaceae)

Seeds of the root parasitesStriga (several spp.) andBuchnera americana were examined by means of SEM. The surface patterns of the seeds in both genera resemble each other closely, especially those ofS. angustifolia andB. americana. SomeStriga spp. can be clearly distinguished by their surface characteristics, while this is quite difficult in others. The taxonomic value of the seed surface features ofStriga andBuchnera is discussed.     

Heterochromatin (C-bands) in somatic and male germ cells in three species ofMicrotinae

The C-banding patterns in the chromosomes ofMicrotus oeconomus, M. arvalis andM. ochrogaster demonstrate differences in the amount and distribution of heterochromatin. Autosomal centromeric heterochromatin appears as conspicuous blocks or as small dots, and in several chromosomes no heterochromatin was detected; interstitial heterochromatin was observed in one autosome pair ofM. ochrogaster. The sex chromosomes also demonstrate differences in the C-banding pattern. InM. oeconomus, the X chromosome exhibits a block of centromeric heterochromatin which is larger than that of the autosomes; this characteristic helps to recognize the X chromosomes in the karyotype. InM. arvalis no heterochromatin was appreciated in the sex chromosomes. The Y chromosomes ofM. ochrogaster andM. oeconomus are entirely heterochromatic. During male meiosis heterochromatin shows condensation, association and chiasma prevention; the sex chromosomes pair end to end in the three species. At pairing, the Y chromosome ofM. arvalis is despiralized, but it appears condensed again shortly before separation of the bivalent.     

Anthelmintic activity of 3,6-dibenzyl-2,5-dioxopiperazine, cyclo(L-Phe-L-Phe)

Summary After oral administration, dipeptide Phe-Phe-OMe1 exhibits anthelmintic activity againstEchinococcus multilocularis larvae, cestoda, in mongolian gerbils (intraperitoneal localization), but not againstHymenolepis nana, cestoda, in fasted mice (gastro-intestinal localization). This compound rapidly provides its cyclization product dioxopiperazine2 in pH 7.4 buffer at 37°C, but was stable at pH 2.4 during 16h at 30°C. It was postulated that dipeptide1 could act as a prodrug of2. Initial pharmacokinetics studies were carried out in mice and dogs. After oral administration, biotransformation of1 into2 occurred to some extent in mice but not in fasted dogs. Results of these studies did not allow to ascertain that1 is a prodrug of2. Compound2 has been tested in mice againstH. nana andSchistosoma mansoni, a gastrointestinal trematoda. Albeit less active than the reference compound praziquantel,2 has shown a good activity against both worms. 2,5dioxopiperazines represent therefore a new class of anthelmintics.     

Uses,nutritional composition,and ecogeography of four species ofPsophocarpus (fabaceae,phaseoleae) in Zaire

In Zaire the distribution of four of the wild species in the genusPsophocarpus ranges from humid, evergreen, Guinea-Congolian rainforests to high altitude woodlands, dry semi-deciduous forests, and savanna. Material ofPsophocarpus scandens, P. grandiflorus, P. lancifolius, P. lecomtei, andP. lancifolius (yellow-seeded form) were collected from wild and naturalized populations in Zaire. Various organs ofP. scandens, P. grandiflorus, andP. lancifolius are used as food sources, medicinals, and as sources of tannins.Psophocarpus lancifolius andP. lecomtei have reportedly been used as a food source and fish poison, respectively. The various organs were analyzed for carbohydrate, lipid, N, S, P, K, Mg, Ca, Na, Fe, Al, Mn, B, Cu, and Zn. In their own right, these species have potential for wider use as food sources and genetic material for improvement breeding with the cultivated winged bean, Local names, phenological notes, presence of pests and diseases, and ecogeographical information are presented.     

Mycoparasitic actions against fungi and oomycetes by a strain (CCFEE 5003) of the fungusLecanicillium muscarium isolated in Continental Antarctica

A strain (CCFEE 5003) ofLecanicillium muscarium, isolated in Continental Antarctica,showed mycoparasitism in agar cocultures, at 5 and 25 °C, againstMucor mucedo, Botrytis cinerea, Pythium aphanidermatum andPhytophthora palmivora. Different sequential steps were observed in the process leading to parasitism and resulting in a complete host disruption. Parasitism against fungi was characterised by diffused penetration into the host mycelium; with oomycetes, penetration was less evident and the contact between the two organisms was more intimate. Production of glucanolytic and chitinolytic enzymes appeared related to the mycoparasitic process.     

Effect of some plant extracts on two coccinellid predators of the cowpea aphid,Aphis craccivora (Hom.: Aphididae)

This study was conducted to examine the effects of some aphicidal biologically active plant compounds on the natural enemies of the cowpea aphid,Aphis craccivora Koch. In the laboratory, acetone extracts ofCymbopogon citratus (DC) Stapf.,Momordica charantia L.,Zingiber officinale Rose andAframomum melegueta (Rose) K. Schum, were tested for toxicity to two coccinellid species,Cheilomenes lunata (Fabricius) andCheilomenes vicina (Mulsant) predaceous on the aphid. All the extracts were highly ovicidal to eggs of the two coccinellid predators. None of the extracts caused mortality of eitherC. lunata orC. vicina fourth-instar larvae after 24 h. Larvae treated with the extracts consumed fewer aphids in 24 h than untreated larvae. Ability to pupate was also significantly reduced in larvae treated with the extracts. No morphological deformities were observed in adults emerging from treated larvae.     

Biological Activity and Food Analysis ofCyttaria spp. (Discomycetes)

The biological activity and nutritional composition of Chilean collections ofCyttaria berteroi C. darwinii, C. espinosae, C. harioti andC. johowii have been determined. The crude protein, lipid, ash, and carbohydrate content of the samples examined were similar to that of other edible fungi. Amino acid analysis of ChileanCyttaria showed that proteins of all species are deficient in methionine and cysteine and excepting oneC. espinosae collection, all samples proved to be below the WHO values for the essential amino acids valine, isoleucine, leucine, and lysine. The acute oral toxicity test ofC. espinosae in rats showed that doses up to 2.5 g extract/kg body weight (corresponding to 25.7–38.7 g fresh weight/kg) did not produce mortality or macroscopic damage in the organs examined of the test animals. Cyttaria extracts assayed at 50 fig/ml were inactive or moderately active as inhibitors towards the enzymes xanthine oxidase (0-31%) and β-glucuronidase (0-65%), and lacked antifungal and antibacterial effects in a battery of antimicrobial assays. When administered intravenously at 2.5 mg/kg, the water-soluble extract ofCyttaria produced a hypotensive response in rats (-16 to -21%). Furthermore, most of the aqueous extracts ofC. espinosae andC. harioti showed DNA binding activity. The main sterols fromCyttaria espinosae andC. berteroi were identified as dihydrobrassicasterol derivatives. Our study suggests that edibleCyttaria species do not represent an acute toxicity risk for consumers and that their nutritional value is similar to that of other edible, cultivated mushrooms. The preservation ofCyttaria spp. as a food resource is linked to the protection of the temperateNothofagus forests.     

New records of Peruvian Mikania (Compositae)

Mikania macrostipulata sp. nov. is described, illustrated, and discussed.Mikania dioscoreoides, M. sprucei, andM. trifolia are reported new to Peru. The heterogeneity of the type material ofM. stereodes is also discussed.     

Myriophyllum quitense and myriophyllum ussuriense (Haloragaceae) in British Columbia,Canada

Myriophyllum quitense andM. ussuriense are added to the flora of British Columbia, Canada.Myriophyllum quitense has not been previously reported in Canada, and this is the first report ofM. ussuriense for the North American continent. Problems with the identification of these species, and their distributions and habitats are discussed. The somatic chromosome numbers of 2n=42 forM. quitense and 2n=21 forM. ussuriense were found. A key for the identification ofMyriophyllum taxa growing in British Columbia is given.