Linden (Tilia cordata) associated bumble bee mortality: Metabolomic analysis of nectar and bee muscle.

Linden (Tilia spp.), a profusely flowering temperate tree that provides bees with vital pollen and nectar, has been associated with bumble bee (Bombus spp.) mortality in Europe and North America. Bee deaths have been attributed, with inadequate evidence, to toxicity from mannose in nectar or starvation due to low nectar in late blooming linden. Here, we investigated both factors via untargeted metabolomic analyses of nectar from five T. cordata trees beneath which crawling/dead bumble bees (B. vosnesenskii) were observed, and of thoracic muscle of 28 healthy foraging and 29 crawling bees collected from linden trees on cool mornings (< 30°C). Nectar contained the pyridine alkaloid trigonelline, a weak acetylcholinesterase inhibitor, but no mannose. Principal component analysis of muscle metabolites produced distinct clustering of healthy and crawling bees, with significant differences (P<0.05) in 34 of 123 identified metabolites. Of these, TCA (Krebs) cycle intermediates were strongly represented (pathway analysis; P<0.01), suggesting that the central metabolism is affected in crawling bees. Hence, we propose the following explanation: when ambient temperature is low, bees with energy deficit are unable to maintain the thoracic temperature required for flight, and consequently fall, crawl, and ultimately, die. Energy deficit could occur when bees continue to forage on linden despite limited nectar availability either due to loyalty to a previously energy-rich source or trigonelline-triggered memory/learning impairment, documented earlier with other alkaloids. Thus, the combination of low temperature and nectar volume, resource fidelity, and alkaloids in nectar could explain the unique phenomenon of bumble bee mortality associated with linden.

Genotoxicidad de Justicia pectoralis Jacq: (tilo) / Genotocixity of Justicia pectoralis Jacq: (tilo)

Objetivo: determinar el efecto genotóxico del extracto hidroalcohólico 30 por ciento de partes aéreas de Justicia pectoralis Jacq. (variedad pectoralis) secado por spray dryer. Métodos: se empleó el ensayo Salmonella/microsomas con las líneas TA 1535, TA 1537, TA 98 y TA 100 con un rango de concentraciones de 50 a 5 000 mg de polvo/placa (± S9) según el protocolo de incorporación en placas; para el ensayo de micronúcleos en médula ósea se utilizaron ratones Cenp: NMRI de los 2 sexos, que recibieron dosis isovolumétricas (10 mL/kg) de 500, 1 000 y 2 000 mg de polvo/kg, por vía intragástrica, separadas 24 h, con sacrificio 24 h después de la última aplicación. Resultados: no se encontró efecto genotóxico con ninguna de las cepas en el ensayo de Salmonella/microsomas y el extracto no causó un aumento estadísticamente significativo en la frecuencia de eritrocitos policromáticos micronucleados en los ratones tratados y no mostró relación dosis respuesta positiva. Conclusiones: el polvo no reveló efecto genotóxico en las condiciones experimentales de este estudio(AU)

Objective: to detemine the genotoxic effect of the hydroalcoholic extract 30 % of aerial parts of Justicia pectoralis Jacq. (variety pectoralis) dried by spray drier. Methods: the Salmonella/microsomes with lines TA 1535, TA 1537, TA 98 and TA 100 with a concentration range from 50 to 5 000 ìg of powder/plaque (± S9) was used according to the protocol of incorporation in plaques; for the bone marrow micronucleus assay there were used Cenp mice: NMRI of both sexes that received isovolumetric doses (10 mL/kg) of 500, 1 000 y 2 000 mg of powder/kg by intragastric route at intervals of 24 h and were sacrificed 24 h after the last application. Results: no genotoxic effect was found with any of the strains in the assay of Salmonella/microsomes. The extract did not cause a statistically significant increase in the frequency of micronucleated polychromatic erythrocytes in the mice treated. No dose/positive response relation was observed. Conclusions: the powder did not reveal genotoxic effect under the experimental conditions of this(AU)

Genotoxicidad de Justicia pectoralis Jacq: (tilo) / Genotocixity of Justicia pectoralis Jacq: (tilo)

Objetivo: determinar el efecto genotóxico del extracto hidroalcohólico 30 por ciento de partes aéreas de Justicia pectoralis Jacq. (variedad pectoralis) secado por spray dryer. Métodos: se empleó el ensayo Salmonella/microsomas con las líneas TA 1535, TA 1537, TA 98 y TA 100 con un rango de concentraciones de 50 a 5 000 mg de polvo/placa (± S9) según el protocolo de incorporación en placas; para el ensayo de micronúcleos en médula ósea se utilizaron ratones Cenp: NMRI de los 2 sexos, que recibieron dosis isovolumétricas (10 mL/kg) de 500, 1 000 y 2 000 mg de polvo/kg, por vía intragástrica, separadas 24 h, con sacrificio 24 h después de la última aplicación. Resultados: no se encontró efecto genotóxico con ninguna de las cepas en el ensayo de Salmonella/microsomas y el extracto no causó un aumento estadísticamente significativo en la frecuencia de eritrocitos policromáticos micronucleados en los ratones tratados y no mostró relación dosis respuesta positiva. Conclusiones: el polvo no reveló efecto genotóxico en las condiciones experimentales de este estudio.

Objective: to detemine the genotoxic effect of the hydroalcoholic extract 30 of aerial parts of Justicia pectoralis Jacq. (variety pectoralis) dried by spray drier. Methods: the Salmonella/microsomes with lines TA 1535, TA 1537, TA 98 and TA 100 with a concentration range from 50 to 5 000 ìg of powder/plaque (± S9) was used according to the protocol of incorporation in plaques; for the bone marrow micronucleus assay there were used Cenp mice: NMRI of both sexes that received isovolumetric doses (10 mL/kg) of 500, 1 000 y 2 000 mg of powder/kg by intragastric route at intervals of 24 h and were sacrificed 24 h after the last application. Results: no genotoxic effect was found with any of the strains in the assay of Salmonella/microsomes. The extract did not cause a statistically significant increase in the frequency of micronucleated polychromatic erythrocytes in the mice treated. No dose/positive response relation was observed. Conclusions: the powder did not reveal genotoxic effect under the experimental conditions of this.

Knockdown, residual, and antifeedant activity of pyrethroids and home landscape bioinsecticides against Japanese beetles (Coleoptera: Scarabaeidae) on Linden foliage.

Residual toxicity and leaf protection capability of five pyrethroids, professional and home garden azadirachtin formulations, and six other bioinsecticides for the home landscape were evaluated against the Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), on linden, Tilia cordata L. Capacity of intoxicated beetles to recover and subsequently feed and disperse also was evaluated to provide insight on activity characteristics of the different compounds. Intact shoots were sprayed and left in the field for varying intervals before being challenged with beetles in no-choice and choice tests. All pyrethroids except permethrin gave greater leaf protection, knockdown, and kill than did carbaryl, the standard, after 14 d of weathering. Deltamethrin, cyfluthrin, bifenthrin, and lamda-cyhalothrin gave a high level of protection for at least 19 d, and azadirachtin (Azatin XL) deterred feeding in choice tests for as long as 14 d. Home garden formulations containing pyrethrins in canola oil (Pyola) or azadiractin (Neem-Away) gave good short-term (< 3-d) protection. Formulations of capsaicin, rotenone + pyrethrins, kaolin particle film, D-limonene, or garlic extract were ineffective, the latter two formulations being highly phytotoxic to linden. Results of this study should help support updating of guidelines for insecticidal control of Japanese beetles.

Pharmacological evaluation of the anxiolytic and sedative effects of Tilia americana L. var. mexicana in mice.

The anxiolytic and sedative effects of Tilia americana L. var. mexicana (Schltdl.) Hardin inflorescence extracts and its acute toxicity were tested. Sodium pentobarbital (SP)-induced hypnosis potentiation (SPP), as well as ambulatory activity and anti-anxiety response in three different experimental models were evaluated with hexane and methanol extracts in mice. In order to determine the proper timing of assessments and to identify the most active extract, a 100mg/kg dosage of hexane, ethyl acetate and methanol crude extracts were tested on SPP after 15, 30 and 60min of the administration. Then a dose-response curve was made for the hexane (10-1000mg/kg) and methanol (10-300mg/kg) extracts in all experimental models. Both extracts produced a significant and dose-dependent lengthening in the time of SP, with the methanol extract being more potent than the hexane extract at 60min after administration. Moreover, a significant and dose-dependent attenuation in the anxiety-response in the plus-maze test and exploratory cylinder activity, but also a diminution in the ambulatory activity and in the head dipping response were observed resembling the response to diazepam. Acute toxicity was observed with less dose of methanol extract (LD(50)=375mg/kg) in comparison to the hexane extract (LD(50)>2900mg/kg). Results of the present study shows that Tilia americana var. mexicana possesses depressant activity on the CNS similar to the better-studied species of European Tilia and reinforces its use as anxiolytic and sedative in traditional medicine.

[Interrelationships between yeast fungi and collembolans in soil].

The possibility of feeding on green and newly fallen leaves of the small-leaved lime Tilia cordata was studied for the collembolans Protaphorura armata and Vertagopus pseudocinereus. Young leaves grown under sterile conditions and almost free of yeast fungi were established to be toxic to the collembolan V. pseudocinereus: feeding on them led to the death of the animals. Leaves grown under natural conditions were nontoxic: when used by the collembolans as feed, they provided for collembolan growth and fecundity. Feeding preferences of the collembolans in relation to the yeasts attributed to different ecomorphs-epiphytes, litter saprophytes, pedobionts, and saccharobionts-were studied. Of the 24 yeast strains isolated from plant green parts, litter, and soil and assigned to eight species, no strain was revealed that was not used by the collembolans. However, certain yeast strains were preferable for the collembolans. The population of the V. pseudocinereus collembolans feeding on the yeast Rhodotorula glutinis (nss 31-4) exceeded that grown on Cryptococcus terricola (2044) 1.5-fold. Thus, the collembolans have feeding preferences in relation to yeast fungi, as was shown earlier for mycelial micromycetes. The possible mechanisms of the feeding preferences of the collembolans in relation to yeasts are discussed.