Growth and population structure of Salamandra salamandra (L.) larvae in different limnological conditions

Salamandra salamandra (L.) larvae were studied in three types of aquatic systems, a permanent spring, a rock pool and temporary ponds. Growth was followed throughout ontogenesis until completion of metamorphosis. Growth patterns changed according to the pond type. Temporary ponds were rich in organic matter and subsequently larvae matured more rapidly there than those in a permanent pool or a spring. In the latter, cannibalism appears to be of major ecological importance, enabling survival and metamorphosis of large size tadpoles. The pattern of growth and metamorphosis is compared with European salamanders and the differences are discussed considering adaptations for survival of this species under xeric conditions.     

Growth stimulation in bean (Phaseolus vulgaris L.) by Trichoderma

Trichoderma species are commonly used as biological control agents against phytopathogenic fungi and some strains are able to produce metabolites that enhance plant growth. In the current study we evaluated the production of potential growth-promoting metabolites, rhizosphere competence and endophytism for 101 isolates of Trichoderma from Colombia, and assessed the relationship of these factors to the enhancement of early stages of growth on bean seedlings. Twenty percent of these Trichoderma strains were able to produce soluble forms of phosphate from phosphoric rock. Only 8% of the assessed strains showed consistent ability to produce siderophores to convert ferric iron to soluble forms by chelation. Sixty percent of isolates produced indole-3-acetic acid (IAA) or auxin analogues. The production of any of these metabolites was a characteristic of specific strains, as the ability to produce these metabolites varied greatly within species. Moreover, the production of these substances did not correlate with enhanced growth on bean seedlings, measured as the combined increase in length of roots and aerial parts in the V3 stage of growth. Seven Trichoderma isolates significantly improved the growth of bean seedlings. However, metabolite production varied widely in these seven strains, and some isolates did not produce any of the assessed growth-promoting metabolites. Results indicated that growth was enhanced in the presence of rhizosphere competent and endophytic strains of Trichoderma, and these characteristics were strain-specific and not characteristic for species.     

Cytochemical and immunofluorescence investigations on insulin-like producing cells in the intestine of Mytilus edulis L. (Bivalvia)

Summary Insulin-like immunoreactivity can be localized to cells of the intestine in the-area of the hepatopancreas of Mytilus edulis L. No cross-reactivity can be obtained with anti-glucagon, anti-gastrin, anti-pentagastrin or anticaerulin. The cells containing the substance immunoreactive to mammalian anti-insulin, can be restained with paraldehyde-fuchsin.I thank Prof. A.G.E. Pearse for the opportunity to carry out this work in the Department of Histochemistry, Royal Postgraduate Medical School, London, England. The work was carried out with the aid of a grant from the Studienstiftung des Deutschen Volkes e.V., Germany (FRG).Dedicated to Prof. Dr. Drs. h.c. W. Bargmann at his 70th birthday.     

Biological control of brown rot (Moniliana laxa Ehr.) on apricot (Prunus armeniaca L. cv. Hacıhaliloğlu) by Bacillus, Burkholdria, and Pseudomonas application under in vitro and in vivo conditions

In 2002 and 2003, a study was conducted to determine the effect of bacterial strains, Burkholdria OSU 7, Bacillus OSU 142, and Pseudomonas BA 8, on biological control of brown rot disease (Monilinia laxa Ehr.) on apricot cv. Hacıhaliloğlu in Malatya province of Turkey. Apricot orchard at full blooming stage was inoculated with conidial suspension (1 × 10⁶ spores/ml) of M. laxa Ehr. After inoculation, two apricot trees for each application were treated with each of the three biological control agents (Burkholdria gladii OSU 7, Bacillus subtilis OSU 142, and Pseudomonas putida BA 8) by spraying (1 × 10⁹ cfu/ml) on inoculated branches. Disease incidence was evaluated for untreated (control 1) and four different treatment groups including commercial disease management (control 2, positive control: 3% Bourdox in fall, 50% Cupper at pink flower, 30 g/100 l Corus at first blooming, and 300 g/100 l Captan at last blooming stage) and treatments including each of the three bacterial strains (OSU 7, OSU 142, and BA 8). The results showed that disease incidence for negative control (control 1) was 9.94, which was significantly higher than disease incidence for commercial application (2.57%) or bacterial treatments (2.82–5.00%) in the first year. In 2003, the lowest disease incidence observed in OSU 7 treatment (6.80%), while disease incidence rate for positive control and negative control were 9.45% and 28.46%, respectively. This result may suggest that OSU 7 has potential to be used as biopesticide for effective management of brown rot disease on apricot.     

Effectiveness of three Glomus species in protecting pepper (Capsicum annuum L.) against verticillium wilt

The objective of this work was to study the influence of three Glomus species—Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe, Glomus intraradices (Schenck and Smith) and Glomus deserticola (Trappe, Bloss, and Menge)—on the development of Verticillium-induced wilt in Capsicum annuum cv. Piquillo. Results showed that the effectiveness of arbuscular mycorrhizal fungi (AMF) as biocontrol agents varied among different Glomus species. In pepper colonized by G. intraradices the severity of the disease was even higher than that observed in non-mycorrhizal plants in terms of plant growth and pepper yield. On the other hand, the high effectiveness exhibited by G. mosseae in improving plant growth and the early beginning of the reproductive stage in these plants was not associated with great plant protection and high pepper yield in diseased plants. Only plants associated with G. deserticola had greater yield than non-mycorrhizal ones despite the lower P fertilization applied to the mycorrhizal treatment and this fact was observed in both healthy and diseased plants. It is suggested that the higher specific phosphorus uptake in Verticillium-inoculated plants associated with G. deserticola could contribute to diminish the deleterious effect of pathogen on yield. On the other hand, the possible influence of endogenous phenolics in roots on the tolerance or resistance of pepper against wilt induced by Verticillium dahliae remains unclear.     

Antileishmanial activity of a guaianolide from Tanacetum parthenium (L.) Schultz Bip

Leishmaniasis is one of the major infectious diseases affecting the poorest regions of the world. The present study evaluated the antileishmanial activity of a guaianolide purified from the hydroalcoholic extract of aerial parts of Tanacetum parthenium (L.) Schultz Bip. The isolated compound showed activity against the promastigote form of Leishmania amazonensis, with 50% inhibition (IC₅₀) of cell growth at a concentration of 2.6 μg/ml. For the intracellular amastigote form, this guaianolide reduced by 10% the survival index of parasites in macrophages when it was used at 20.0 μg/ml. The selective index (SI) ratio (CC₅₀ for J774G8 cells/IC₅₀ for protozoans) was 385, showing that it is more selective against the parasite than mammalian cells. Morphological alterations of protozoans treated with IC₅₀ included changes in size, shape, and structure (more than one nucleus and flagellum) under both light and scanning electron microscopies.     

Coinoculation of Bacillus thuringeinsis-KR1 with Rhizobium leguminosarum enhances plant growth and nodulation of pea (Pisum sativum L.) and lentil (Lens culinaris L.)

Nodulation and the subsequent nitrogen fixation are important factors that determine the productivity of legumes. The beneficial effects of nodulation can be enhanced when rhizobial inoculation is combined with plant-growth-promoting bacteria (PGPB). The PGPB strain Bacillus thuringiensis-KR1, originally isolated from the nodules of Kudzu vine (Pueraria thunbergiana), was found to promote plant growth of field pea (Pisum sativum L.) and lentil (Lens culinaris L.) under Jensen’s tube, growth pouch and non-sterile soil, respectively, when co-inoculated with Rhizobium leguminosarum-PR1. Coinoculation with B. thuringiensis-KR1 (at a cell density of 10⁶ c.f.u. ml⁻¹) provided the highest and most consistent increase in nodule number, shoot weight, root weight, and total biomass, over rhizobial inoculation alone. The enhancement in nodulation due to coinoculation was 84.6 and 73.3% in pea and lentil respectively compared to R. leguminosarum-PR1 treatment alone. The shoot dry-weight gains on coinoculation with variable cell populations of B. thuringiensis-KR1 varied from 1.04 to 1.15 times and 1.03 to 1.06 times in pea and lentil respectively, while root dry weight ratios of coinoculated treatments varied from 0.98 to 1.14 times and 1.08 to 1.33 times in pea and lentil respectively, those of R. leguminosarum-PR1 inoculated treatment at 42 days of plant growth. While cell densities higher than 10⁶ c.f.u. ml⁻¹ had an inhibitory effect on nodulation and plant growth, lower inoculum levels resulted in decreased cell recovery and plant growth performance. The results of this study indicate the potential of harnessing endophytic bacteria of wild legumes for improving the nodulation and growth of cultivated legumes.     

Control of the broad mite (Polyphagotarsonemus latus (Banks)) on organic greenhouse sweet peppers (Capsicum annuum L.) with the predatory mite, Neoseiulus cucumeris (Oudemans)

The predatory mite Neoseiulus cucumeris (Oudemans) (Acarina: Phytoseiidae) successfully controlled the broad mite Polyphagotarsonemus latus (Banks) (Acarina: Tarsonemidae) on two varieties of greenhouse-grown sweet peppers (Capsicum annuum L.). A survey of pre-plant seedlings showed that nurseries were a source of infestation for the broad mite. The predatory mites were released twice (on day 1 and 5, or 15 days later) on each plant, every second plant or every fourth plant. Broad mite populations were evaluated by sampling young leaves from the top of the plant. The effect of the broad mite on plant height, dry mass and yield was evaluated. Additionally, since N. cucumeris is known to control thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), blue sticky traps and flower sampling were used to evaluate changes in thrips populations. All three release rates of N. cucumeris significantly (P<0.05) controlled broad mite populations, but when the predatory mites were released only on every fourth plant, the overall height and yield of the plants were adversely affected by broad mites. Releasing N. cucumeris on each or every second plant was as efficacious in controlling broad mites as sulfur treatments in terms of plant height, dry mass and yield. Plants treated with sulfur, however, had significantly higher thrips populations and fruit damage.     

Chemical constituents of Atractylodes chinensis (DC.) Koidz.

Phytochemical investigations of the rhizomes of Atractylodes chinensis (DC.) Koidz. resulted in the isolation of four sesquiterpenes (1–4), five polyacetylenes (5–9), oleanolic acid (10), and 5-hydromethyl furaldehyde (11). Among them, seven compounds (3, 5–10) were firstly isolated from the A. chinensis, and all have been reported in the genus Atractylodes except compound 10. The chemotaxonomic significance of these compounds was summarized.     

Isolation of pure compound R/J/3 from Pluchea indica (L.) Less. and its anti-amoebic activities against Entamoeba histolytica

The plant Pluchea indica is known for its anti-inflammatory, anti-ulcer, anti-pyretic, hypoglycemic, diuretic and anti-microbial activities besides many other pharmacological activities. We have isolated and purified seven compounds from the methanolic root extract of this plant by column chromatography. The compounds were identified by spectroscopic analyses. The anti-amoebic activities of the pure compound R/J/3 was investigated against the HM1 strain of Entamoeba histolytica. The compound, R/J/3 showed the most pronounced anti-proliferative activity at a dose of 50 microg/ml. It also showed a marked activity on cell lysis of trophozoites, 4h after administration. The cell lytic activity was compared with metronidazole (5 microg/ml) as positive control.     

Generalism Versus Specialism: Responses of Diadegma mollipla (Holmgren) and Diadegma semiclausum (Hellen), to the Host Shift of the Diamondback Moth (Plutella xylostella L.) to Peas

A population of the diamondback moth Plutella xylostella (L.) (Lepidoptera: Plutellidae) (DBM) was recently found to infest sugar snap- and snowpeas in the Rift Valley in Kenya, causing heavy damage. The influence of this host shift on host location preferences of two parasitoids was investigated: The indigenous Diadegma mollipla (Holmgren) regarded as a relative generalist, and Diadegma semiclausum(Hellen), regarded as highly specific to DBM. The attractiveness of different odour sources was compared for the two parasitoid species using a Y-tube olfactometer using naïve females. D. mollipla was not significantly attracted to any cabbage related odours but showed a significant preference for the DBM infested pea plant when tested against clean air. D. semiclausum was highly attracted to the undamaged cabbage plant and odours related to cabbage. On the other hand, peas infested with DBM, showed no attractiveness to this parasitoid. The results showed that specialisation of D. semiclausum is mediated by host plant signals, associated with crucifers, which are not encountered in DBM feeding on peas. For D. mollipla,although a frequent parasitoid on DBM in crucifers, volatiles emitted by these plants might not be used as primary cues for host location. This species may respond largely to chemicals yet unknown and associated with a variety of plant-herbivore interactions.     

Biological control of Tipula paludosa (Diptera: Nematocera) using entomopathogenic nematodes (Steinernema spp.) and Bacillus thuringiensis subsp. israelensis

Tipula paludosa (Diptera: Nematocera) is the major insect pest in grassland in Northwest Europe and has been accidentally introduced to North America. Oviposition occurs during late August and first instars hatch from September until mid-October. Laboratory and field trials were conducted to assess the control potential of entomopathogenic nematodes (EPN) (Steinernema carpocapsae and S. feltiae) and Bacillus thuringiensis subsp. israelensis (Bti) against T. paludosa and to investigate whether synergistic effects can be exploited by simultaneous application of nematodes and Bti. Results indicate that the early instars of the insect are most susceptible to nematodes and Bti. In the field the neonates prevail when temperatures tend to drop below 10 °C. S. carpocapsae, reaching >80% control, is more effective against young stages of T. paludosa than S. feltiae (<50%), but the potential of S. carpocapsae might be limited by temperatures below 12 °C. Mortality of T. paludosa caused by Bti was not affected by temperature even at 4 °C but the lethal time increased with decreasing temperatures. Synergistic effects of Bti and EPN against T. paludosa were observed in 3 out of 10 combinations in laboratory assays but not in a field trial. The potential of S. carpocapsae was demonstrated in field trials against early instars in October reaching an efficacy of >80% with 0.5 million nematodes m⁻² at soil temperatures ranging between 3 and 18 °C. Results with Bti were strongly influenced by the larval stage and concentration. Against early instars in autumn between 74 and 83% control was achieved with 13 kg ha⁻¹ Bti of 5,700 International Toxic Units (ITUs) and 20 kg ha⁻¹ of 3,000 ITUs. Applications in spring against third and fourth instars achieved between 0 and 32% reduction. The results indicate that application of Bti and nematodes will only be successful and economically feasible during the early instars and that the success of S. carpocapsae is dependent on temperatures >12 °C. Synergistic effects between S. carpocapsae and Bti require more detailed investigations in the field to determine maximal effect.     

Costs of mass-producing the root weevil, Mogulones cruciger, a biological control agent for houndstongue (Cynoglossum officinale L.)

The cost of rearing the root-feeding weevil, Mogulones cruciger Herbst, to control the invasive weed houndstongue (Cynoglossum officinale L.) was determined for two managed production methods. Production in an insectary setting provides control over rearing and all adult weevils that emerge can be collected, but required facility investment and high labor input. Mass-rearing in a managed ‘field crop’ setting required less facilities and labor while the insects were multiplying, but capture of the emerged adults was challenging and labor intensive. Estimated per adult weevil production costs were $CDN 2.65 for the insectary approach, and from $CDN 0.10 to $CDN 0.14 for mass-rearing in the managed field crop setting. Even though collection of adult weevils in the field crop production system was challenging, commercial production of M. cruciger should consider use of this mass-rearing method because of its lower cost.     

Genotypic and phenotypic characterization of rhizobia that nodulate snap bean (Phaseolus vulgaris L.) in Egyptian soils

Snap bean fields in 12 of the 25 governorates of Egypt were surveyed to determine the distribution and taxonomy of snap bean-nodulating rhizobia. Nodulation rates in the field were very low, indicating that Egyptian soils do not have sufficient numbers of snap bean-compatible Rhizobium spp. A total of 87 rhizobial isolates were assayed on the most commonly grown cultivars in order to identify the most effective strains. The five most effective isolates (R11, R13, R28, R49 and R52) were fast-growing and utilized a wide range of carbon and nitrogen sources. A phylogenetic assignment of these strains by analysis of the 16S ribosomal RNA gene suggested that all fell within the Rhizobium etli–Rhizobium leguminosarum group. Strains R11, R49 and R52 all clustered with other identified R. etli strains, while strains R13 and R28 were more distinct. The distinctness of R13 and R28 was supported by physiological characteristics, such as their ability to utilize citrate, erythritol, dulcitol and lactate. Strains R13 and R28 also yielded the highest plant nitrogen content of all isolates.The highly effective strains isolated in this study, in particular strains R13 and R28, are promising candidates for improving crop yields. The data also suggested that these two strains represented a novel sub-group within the R. etli–R. leguminosarum group. As snap bean is a crop of great economic value to Egypt, the identification of highly effective rhizobial strains adapted to Egyptian soils, such as strains R13 and R28, is of great interest.     

The effect of Euglena viridis on immune response of rohu, Labeo rohita (Ham.)

The study evaluated the effect of dietary doses of Euglena viridis on the immune response and disease resistance of Labeo rohita fingerlings against infection with the bacterial pathogen Aeromonas hydrophila. L. rohita fingerlings were fed with diet containing 0 (Control), 0.1 g, 0.5 g, 1.0 g Euglena powder kg⁻¹ dry diet for 90 days. Biochemical (serum total protein, albumin, globulin, albumin:globulin ratio), haematological (WBC, RBC, haemoglobin content) and immunological (superoxide anion production, lysozyme, serum bactericidal activity) parameters of fish were examined after 30, 60 and 90 days of feeding. Fish were challenged with A. hydrophila 90 days post-feeding and mortalities were recorded over 10 days post-infection. The results demonstrate that fish fed with Euglena showed increased levels of superoxide anion production, lysozyme, serum bactericidal activity, serum protein and albumin (P < 0.05) compared with the control group. Following challenge with A. hydrophila less survivability was observed in the control group (56.65%) than the group fed the experimental diets. The group fed 0.5 g Euglena kg⁻¹ dry diet showed the highest percentage survival (75%). These results indicate that Euglena stimulates the immunity and makes L. rohita more resistant to A. hydrophila infection.     

Insecticidal effect of Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreaes) in combination with three diatomaceous earth formulations against Sitophilus granarius (L.) (Coleoptera: Curculionidae)

The insecticidal effect of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreaes) in combination with three diatomaceous earth (DE) formulations against adults of the granary weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae) was tested in the laboratory. The three DEs were Insecto™, SilicoSec^® and PyriSec^®. The fungus was applied at 400 ppm alone, or in combination with 200 ppm of each of the three DEs. Mortality was measured after 7 d of exposure. Bioassays were conducted at three temperatures 20, 25 and 30 °C and two relative humidities (rh) 55% and 75%. On wheat treated with B. bassiana alone, mortality was higher at 55% than at 75% rh. Also, the fungus alone was less effective at 20 °C than at the other two temperatures tested, but mortality did not exceed 52% for any of the conditions tested. Similar mortality levels were also noted on wheat treated with each of the three DEs alone. The simultaneous presence of B. bassiana and DE increased weevil mortality. In this combination, mortality was higher at high temperatures and low rh, and this effect was similar for all DEs tested. Progeny production on wheat treated with B. bassiana was higher that the respective progeny counts in the DE-treated wheat. The results indicate that a combination of B. bassiana and DEs is effective against S. granarius, under a broad range of temperature and rh levels in stored wheat.     

The phylogenetic placement of the Leucogastrales, including Mycolevis siccigleba (Cribbeaceae), in the Albatrellaceae using morphological and molecular data

The morphology of many hypogeous fungi converges on a homogeneous reduced form, suggesting that disparate lineages are subject to a uniform selection pressure. The primary goal of this study was to evaluate the morphology and infer the phylogeny of the Leucogastrales with Mycolevis siccigleba using a Bayesian methodology. A comprehensive morphological assessment was used for an a priori phylogenetic inference to guide the sequencing effort. All structures except spore ornamentation pointed to the Albatrellaceae as the most likely sister taxon. Polyporoletus sublividus, a close relative of Albatrellus, produces ornamented basidiospores with a similar structure to M. siccigleba basidiospores. The ITS from 30 taxa was used for the molecular phylogenetic analysis. P. sublividus was found sister to Mycolevis. Leucophleps spinispora and L. magnata formed a group sister to the Polyporoletus/Mycolevis group, whereas Leucogaster was polyphyletic with respect to the core of the Leucogastrales and sister to A. caeruleoporus. This relationship was expected as previously undescribed chlamydospores produced by members of Albatrellus had a similar morphology to the basidiospores of L. rubescens.     

Antimutagenicity of hops (Humulus lupulus L.): bioassay-directed fractionation and isolation of xanthohumol

Bioassay-directed fractionation with a Salmonella/microsomal assay against the food borne mutagen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) was used to identify antimutagenic components of hops. Hops pellets extracted with diethylether showed antimutagenic activity against mutations induced by IQ. Fractionation of the diethylether extract (DE) by column chromatography, followed by semi-preparative HPLC yielded two fractions (E4b and E4d) with strong antimutagenic activity against IQ induced mutations. Separation of fraction E4b resulted in inactive fractions, while fraction E4d has been identified to be xanthohumol. In mammalian test system with human hepatoma HepG2 cells fraction E4d at 10 μg/ml completely prevented formation of IQ induced DNA damage. These results indicate that xanthohumol is a very promising potential protective agent against genotoxicity of food borne carcinogens, which warrants further investigation.