Young honeybees show learned preferences after experiencing adulterated pollen.

Pollen selection affects honeybee colony development and productivity. Considering that pollen is consumed by young in-hive bees, and not by foragers, we hypothesized that young bees learn pollen cues and adjust their preferences to the most suitable pollens. To assess whether young bees show preferences based on learning for highly or poorly suitable pollens, we measured consumption preferences for two pure monofloral pollens after the bees had experienced one of them adulterated with a deterrent (amygdalin or quinine) or a phagostimulant (linoleic acid). Preferences were obtained from nurse-aged bees confined in cages and from nurse bees in open colonies. Furthermore, we tested the bees' orientation in a Y-maze using a neutral odour (Linalool or Nonanal) that had been previously associated with an amygdalin-adulterated pollen. Consumption preferences of bees, both in cages and in colonies, were reduced for pollens that had been adulterated with deterrents and increased for pollens that had been supplemented with linoleic acid. In the Y-maze, individuals consistently avoided the odours that they had previously experienced paired with the deterrent-adulterated pollen. Results show that nurse-aged bees associate pollen-based or pollen-related cues with either a distasteful/malaise experience or a tasty/nutritious event, leading to memories that bias their pollen-mediated response.

Recombinants from the crosses between amphidiploid and cultivated peanut (Arachis hypogaea) for pest-resistance breeding programs.

Peanut is a major oilseed crop worldwide. In the Brazilian peanut production, silvering thrips and red necked peanut worm are the most threatening pests. Resistant varieties are considered an alternative to pest control. Many wild diploid Arachis species have shown resistance to these pests, and these can be used in peanut breeding by obtaining hybrid of A and B genomes and subsequent polyploidization with colchicine, resulting in an AABB amphidiploid. This amphidiploid can be crossed with cultivated peanut (AABB) to provide genes of interest to the cultivar. In this study, the sterile diploid hybrids from A. magna V 13751 and A. kempff-mercadoi V 13250 were treated with colchicine for polyploidization, and the amphidiploids were crossed with A. hypogaea cv. IAC OL 4 to initiate the introgression of the wild genes into the cultivated peanut. The confirmation of the hybridity of the progenies was obtained by: (1) reproductive characterization through viability of pollen, (2) molecular characterization using microsatellite markers and (3) morphological characterization using 61 morphological traits with principal component analysis. The diploid hybrid individual was polyploidized, generating the amphidiploid An 13 (A. magna V 13751 x A. kempff-mercadoi V 13250)4x. Four F1 hybrid plants were obtained from IAC OL 4 × An 13, and 51 F2 seeds were obtained from these F1 plants. Using reproductive, molecular and morphological characterizations, it was possible to distinguish hybrid plants from selfed plants. In the cross between A. hypogaea and the amphidiploid, as the two parents are polyploid, the hybrid progeny and selves had the viability of the pollen grains as high as the parents. This fact turns the use of reproductive characteristics impossible for discriminating, in this case, the hybrid individuals from selfing. The hybrids between A. hypogaea and An 13 will be used in breeding programs seeking pest resistance, being subjected to successive backcrosses until recovering all traits of interest of A. hypogaea, keeping the pest resistance.

IMI resistance associated to crop-weed hybridization in a natural Brassica rapa population: characterization and fate.

Wild turnip (Brassica rapa) is a common weed and a close relative to oilseed rape (Brassica napus). The Clearfield® production system is a highly adopted tool which provides an alternative solution for weed management, but its efficiency is threatened by gene transfer from crop to weed relatives. Crop-weed hybrids with herbicide resistance were found in the progeny of a B. rapa population gathered from a weedy stand on the borders of an oilseed rape (B. napus) imidazolinone (IMI)-resistant crop. Interspecific hybrids were confirmed by morphological traits in the greenhouse and experimental field, survival after imazethapyr applications, DNA content through flow cytometry, and pollen viability. The transference of herbicide resistance was demonstrated even in a particular situation of pollen competition between both an herbicide-resistant crop and a non-resistant crop. However, IMI resistance was not found in further generations collected at the same location. These results verify gene transmission from oilseed rape to B. rapa in the main crop area in Argentina where resistant and susceptible varieties are found and seed loss and crop volunteers are common. Hybridization, introgression, and herbicide selection would be associated with the loss of effectiveness of IMI technology.

Boron and Coumaphos Residues in Hive Materials Following Treatments for the Control of Aethina tumida Murray.

In the search of alternatives for controlling Aethina tumida Murray, we recently proposed the BAA trap which uses boric acid and an attractant which mimics the process of fermentation caused by Kodamaea ohmeri in the hive. This yeast is excreted in the feces of A. tumida causing the fermentation of pollen and honey of infested hives and releasing compounds that function as aggregation pheromones to A. tumida. Since the boron is the toxic element in boric acid, the aim of this article is to assess the amount of boron residues in honey and beeswax from hives treated with the BAA trap. For this aim, the amount of bioaccumulated boron in products of untreated hives was first determined and then compared with the amount of boron of products from hives treated with the BAA trap in two distinct climatic and soil conditions. The study was conducted in the cities of Padilla, Tamaulipas, and Valladolid, Yucatan (Mexico) from August 2014 to March 2015. The quantity of boron in honey was significantly less in Yucatan than in Tamaulipas; this agrees with the boron deficiency among Luvisol and Leptosol soils found in Yucatan compared to the Vertisol soil found in Tamaulipas. In fact, the honey from Yucatan has lower boron levels than those reported in the literature. The BAA treatment was applied for four months, results show that the BAA trap does not have any residual effect in either honey or wax; i.e., there is no significant difference in boron content before and after treatment. On the other hand, the organophosphate pesticide coumaphos was found in 100% of wax samples and in 64% of honey samples collected from Yucatan. The concentration of coumaphos in honey ranges from 0.005 to 0.040 mg/kg, which are below Maximum Residue Limit (MRL) allowed in the European Union (0.1 mg/kg) but 7.14% of samples exceeded the MRL allowed in Canada (0.02 mg/kg).

Effects of silicon on seed setting rate of rice intersubspecific hybrids.

The present study found semi-sterility in rice intersubspecific hybrids of 'Taichung 65' x 'Guangluai 4' and 'Ludao' x 'Qiuguang'. Embryo sac fertility was evaluated using the overall staining transparent method. The results showed that the embryo sac contained a normal egg cell, normal synergid cells, polar nuclei cells, and antipodal cells, indicating that semi-sterility was caused mainly by pollen semi-sterility. In the pot experiment, the effects of silicon on the seed-setting rate of the two intersubspecific hybrids were examined. The results showed that the rate of anther dehiscence, number of pollen per stigma of Fl plants, potential of pollen grain germination, and fertility of the spikelet were significantly improved by the utilization of silicon fertilizer.

Micronucleus study of the quality and mutagenicity of surface water from a semi-arid region.

The present study evaluated the mutagenic potential of surface water from the Lucrecia dam. The Tradescantia-micronucleus (Trad-MCN) test and CBMN assay in human peripheral blood lymphocytes were applied, corresponding to an in vivo and in vitro system, respectively. Heavy metals and some physicochemical properties were also measured. Water samples were collected in November 2009 (dry season) and May 2010 (rainy season) at three different points. Results of both assays for raw water showed positive responses for the points analyzed when compared to the negative control. The CBMN assay showed that diluted water was still able to induce a significant increase in micronucleus frequency. For both assays, the highest mean MN was observed in the dry season. Chemical analyses detected an increase in heavy metal levels at the sampling points and in the different seasons. These findings indicate the presence of genotoxins, such as heavy metals, in the water, which may be affecting the entire ecosystem, as well as human health. More prolonged monitoring is recommended in order to better characterize this public water supply.

Effects of low-energy argon ion implantation on the dynamic organization of the actin cytoskeleton during maize pollen germination.

The relationship between pollen germination and the dynamic organization of the actin cytoskeleton during pollen germination is a central theme in plant reproductive biology research. Maize (Zea mays) pollen grains were implanted with 30 keV argon ion (Ar(+)) beams at doses ranging from 0.78 x 10(15) to 13 x 10(15) ions/cm(2). The effects of low-energy ion implantation on pollen germination viability and the dynamic organization of the actin cytoskeleton during pollen germination were studied using confocal laser scanning microscopy. Maize pollen germination rate increased remarkably with Ar(+) dose, in the range from 3.9 x 10(15) to 6.5 x 10(15) ions/cm(2); the germination rate peaked at an Ar(+) dose of 5.2 x 10(15) ions/cm(2). When the implantation dose exceeded 7.8 x 10(15) ions/cm(2), the rate of pollen germination decreased sharply. The actin filaments assembled in pollen grains implanted with 5.2 x 10(15) ions/cm(2) Ar(+) much earlier than in controls. The actin filaments organized as longer parallel bundles and extended into the emerging pollen tube in treated pollen grains, while they formed random and loose fine bundles and were gathered at the pollen aperture in the control. The reorganization of actin cytoskeleton in the pollen implanted with 9.1 x 10(15) ions/cm(2) Ar(+) was slower than in controls. There was a positive correlation between pollen germination and the dynamic organization of the actin cytoskeleton during pollen germination. Ion implantation into pollen did not cause changes in the polarization of actin filaments and organelle dynamics in the pollen tubes. The effects of Ar(+) implantation on pollen germination could be mediated by changes in the polymerization and rearrangement of actin polymers.

Toxicity screening of mouthwashes in the pollen tube growth test: safety assessment of recommended dilutions.

This study investigated whether mouthwash dilutions, recommended by the manufacturers, may contribute to oral mucosa irritation. Twenty frequently used mouthwash brands were examined by the pollen tube growth test, an alternative in vitro method for assessment of the irritating potential of ingredients of cosmetic formulations. The test is based on the photometric quantification of pollen tube growth inhibition. This parameter is expressed by IC50 values that characterize the cytotoxic potential of a product. The IC50s clearly revealed that none of the tested mouthwashes should cause acute irritation if used in the recommended dilution. However, at least 4 of the mouthwashes evaluated in this study could probably irritate the oral mucosa acutely if used undiluted (original concentration).

Toxicity screening of mouthwashes in the pollen tube growth test: safety assessment of recommended dilutions

Este estudo investigou se soluções de bochecho nas diluições recomendadas pelos fabricantes podem contribuir para a irritação das mucosas orais. Vinte soluções de bochecho frequentemente utilizadas foram avaliadas por meio do análise do crescimento do tubo polínico. Este teste constitui um método alternativo in vitro para estimar o potencial irritante dos ingredientes de formulações cosméticas. O teste baseia-se numa medição fotométrica da inibição do crescimento de tubos polínicos. A inibição do crescimento é expressa por valores IC50 que caracterizam o potencial citotóxico de uma dada substância. Os valores de IC50 aqui apresentados demonstraram que nenhuma das soluções de bochecho estudadas deve causar irritação aguda das mucosas orais, desde que utilizadas nas diluições recomendadas pelo fabricante. No entanto, verificou-se que pelo menos quatro dos colutórios podem causar irritação aguda das mucosas orais ao serem utilizados na a forma concentrada.