Quality and safety of maize (Zea mays L.) from Rondônia state storage units,Northern Brazil

The quality and safety of maize (Zea mays L.) from different grain storage units (GSUs), located in the main producing region of Rondônia State, Northern Brazil, were evaluated. Maize grains (n = 76) stored in four GSUs were collected from July to November 2014 and evaluated for grain damages, humidity, fungi and fumonisins (FBs) content. The climate conditions data were also obtained from plant growing to storage periods. Regarding the moisture content and water activity (a_w), these varied from 10.0% to 16.1% and 0.5 to 0.8, respectively. As expected, fungi spores were present in 94.8% of the samples, prevailing Fusarium genera, with a fungi colony maximum of 2.2 × 10⁴ CFU g^?1. Regarding FBs, 60.5% of the samples were contaminated, below Brazilian and United States maximum limits, but 9.2% had levels higher than the European legislation.     

Collection efficiency of liquid‐based samplers for fungi in indoor air

This study assessed the collection efficiency (CE) of two popularly used sampling devices (BioSampler and Coriolis sampler) for fungal aerosols. Phosphate‐buffered saline (PBS) supplemented with or without surfactant (Tween‐20, Tween‐80, or Triton X‐100) and antifoam agent was prepared and used as collection liquids. The agar impactor (BioStage) was simultaneously operated with liquid‐based samplers to collect fungi from seven sites located at a university building, public library, and animal farming. Fungal concentrations determined by liquid samplers were divided by those by BioStage, and the ratio values represented CE. Results indicate that the CE of BioSampler was superior to that of Coriolis (P = 0.0001) and the PBS containing surfactant collected fungi better than that without surfactant (P < 0.0001), whereas antifoam agent showed no influence (P = 0.8). Moreover, fungal concentrations determined by BioSampler with surfactant‐added PBS were statistically indifferent from those by BioStage (P > 0.05) with a Spearman correlation coefficient of 0.81‐0.83 (P < 0.01). In addition to sampler and collection liquid, sampling location was also identified as a significant CE factor (P = 0.006), implying potential influences by fungal genera in the studied fields. Overall, BioSampler with surfactant‐supplemented PBS (eg, Triton X‐100) is recommended considering the great CE and compatibility with a variety of analytical assays.     

<i>Claroideoglomus etunicatum</i> improved the growth and saline– alkaline tolerance of <i>Potentilla anserina</i> by altering physiological and biochemical properties

To investigate the effects of arbuscular mycorrhizal (AM) fungi on the growth and saline–alkaline tolerance of Potentilla anserina L., the seedlings were inoculated with Claroideoglomus etunicatum (W.N. Becker & Gerd.) C. Walker & A. Schüßler in pot cultivation. After 90 days of culture, saline–alkaline stress was induced with NaCl and NaHCO₃ solution according to the main salt components in saline–alkaline soils. Based on the physiological response of P. anserina to the stress in the preliminary experiment, the solution concentrations of 0 mmol/L, 75 mmol/L, 150 mmol/L, 225 mmol/L and 300 mmol/L were treated with stress for 10 days, respectively. The mycorrhizal colonization rate, mycorrhizal dependence, chlorophyll content, malondialdehyde content, antioxidant enzyme activities, osmoregulation substances content and water status were measured. The results showed that with the increase of NaCl and NaHCO₃ stress concentration, mycorrhizal colonization rate, colonization intensity, arbuscular abundance and vesicle abundance decreased, and reached the lowest value at 300 mmol/L. Strong mycorrhizal dependence was observed after the symbiosis with AM fungus, and the dependence was higher under NaHCO₃ treatment. Under NaCl and NaHCO₃ stress, inoculation with AM fungus could increase chlorophyll content, decrease malondialdehyde content, increase activities of superoxide dismutase, peroxidase and catalase, increase contents of proline, soluble sugar and soluble protein, increase tissue relative water content and decrease water saturation deficit. It was concluded that salt–alkali stress inhibited the colonization of AM fungus, but the mycorrhiza still played a positive role in maintaining the normal growth of plants under salt–alkali stress.     

Efficacy of different entomopathogenic fungal isolates against four key stored-grain beetle species

The development of resistance in stored-grain insect pests can be effectively reduced by using biological control methods. Entomopathogenic fungi have been under consideration as complementary and alternative agents to synthetic insecticides. The aim of this study is to identify the pathogenic potential of four different fungal isolates of Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Cordycipitaceae) (WG-47, WG-48, WG-50, WG-51) and three isolates of Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae) (WG-46, WG-49, WG-52) against the adult stages of the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), the granary weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae), the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) at 1 × 10⁶, 1 × 10⁷, 1 × 10⁸ and 1 × 10⁹ conidia/kg wheat. Mortality was found dose dependent among all the tested species. Rhyzopertha dominica was the most susceptible followed by S. granarius, T. castaneum and T. granarium. Among the different isolates B. bassiana caused higher mortality compared to M. anisopliae. The isolates WG-50 and WG-51 of B. bassiana provided maximum mortality among the different tested species and led to lower F1 individuals compared to the controls. Our study indicates that entomopathogenic fungi have an elevated potential to successfully manage the aforementioned coleopteran species on stored wheat.     

Can we use indoor fungi as bioindicators of indoor air quality? Historical perspectives and open questions

Microbiological analysis of atmospheres witnessed substantial technical improvements in the 1940s to 1960s. May's cascade impactor and Hirst's spore trap allowed the counting of total cells but had limited capacity for identification of the spores. Bourdillon's sampler enabled the counting of cultivable fungi and their identification. A great step forward was given with the Andersen's six-stage impactor, which allowed discrimination of particles by size, counting of cultivable cells, and species identification. This period also witnessed the development of impingers, namely, the AGI-30 described by Malligo and Idoine, and the three-stage model designed by K. R. May. The 1990s to 2000s witnessed innovative discoveries on the biology of indoor fungi. Work carried out in several laboratories showed that indoor fungi can release groups of spores, individual spores and fungal fragments, and produce volatile organic compounds and mycotoxins. Integrating all findings a holistic interpretation emerged for the sick building syndrome. Healthy houses and buildings, with low indoor humidity, display no appreciable indoor fungal growth, and outdoor Cladosporium dominates. On the contrary, in sick houses and buildings, high indoor humidity allows fungal growth (mainly of Penicillium and Aspergillus), with concomitant release of conidia and fragments into the atmosphere. The intoxication probably results from a chronic exposure to volatile organic compounds and mycotoxins produced by Penicillium, Aspergillus, and Stachybotrys.Very clean atmospheres are difficult to study by conventional methods. However, some of these atmospheres, namely, those of hospital rooms, should be monitored. Sedimentary sampling, chemical methods applied to impinger's collection liquid, and selected molecular methods can be useful in this context.It was concluded that fungi can be useful indicators of indoor air quality and that it is important to deepen the studies of indoor atmospheres in order to promote air quality, the health and well-being of all, and a better understanding of the biology of indoor fungi.     

菌根菌在古松抢救复壮中的应用

菌根菌对松树的生长具促进作用。对生长衰弱的古白皮松、古五针松、古雪松等古松根部施用菌根菌进行抢救复壮的试验结果表明:古松的新生枝条长度、针束数、新针长度、根的鲜重与干重均显著增加。在古松根部施用菌根菌,是对古松抢救复壮时的一种非常有效的办法。