Plant and carabid beetle species diversity in relation to forest type and structural heterogeneity

The aim of this study was to evaluate the influence of forest structure (mainly resulting from human uses) and forest type (the identity of the dominant tree species) on biodiversity. We determined the diversity of two taxonomical groups: the understory vegetation and the edaphic carabid beetle fauna. We selected eight types of forest ecosystems (five replicates or stands per forest type): pine (Pinus sylvestris) plantations of three age classes (10, 40 and 80 years since reforestation), an old-growth relict natural pine forest, and four types of oak (Quercus pyrenaica) stands: mature forests with livestock grazing and firewood extraction, mature forests where uses have been abandoned, “dehesa” ecosystems and shrubby oak ecosystems. The results obtained by a global PCA analysis indicated that both tree size and dominant species influenced the ordination of the 40 forest stands. In general, carabids were more sensitive to changes in forest heterogeneity and responded more clearly to the analysed structural variables than the understory vegetation, although the species richness of both groups was significantly correlated and higher in case of oak forests. Pine forest ecosystems were characterised by the lowest species richness for both taxonomical groups, the lowest plant diversity and by the lowest coefficients of variation and, consequently, low structural heterogeneity. As a result, it was very difficult to discriminate the effects of the spatial heterogeneity and the dominant tree species on biodiversity.     

Molecular,morphological and pathogenic diversity of Sclerotinia sclerotiorum isolates from common bean (Phaseolus vulgaris) fields in Argentina

White mould, caused by Sclerotinia sclerotiorum, is one of the most threatening fungal diseases occurring across major bean production regions worldwide. In Argentina, under favourable weather conditions, up to 100% seed yield losses occur on susceptible common bean cultivars. The aim of this study was to characterize the diversity of S. sclerotiorum isolates from six dry bean fields in the main production area of Argentina by means of molecular, morphological (mycelium colour, number and pattern of sclerotia distribution) and pathogenic approaches. Among 116 isolates analysed, high genotypic and morphological variability was observed. A total of 52 mycelial compatibility groups (MCGs) and 59 URPs (universal rice primers) molecular haplotypes were found. All the MCGs were location specific, while only 12% of the URP haplotypes were shared among locations. The molecular analysis of variance revealed a significant differentiation among populations, with higher genetic variability within the populations analysed than among them. The aggressiveness of the isolates towards bean seedlings was assessed in the greenhouse. Most of the isolates were highly aggressive, while no variation among locations was observed. The information generated in the present study provides, for the first time, information on the variability of S. sclerotiorum associated with white mould in the main common bean production area in Argentina. In addition, the findings suggest the occurrence of both clonal and sexual reproduction in the populations analysed. This work contributes to the development of sustainable management strategies in bean production aimed to minimize yield losses due to white mould.     

Optimizing nursery and plantation methods to grow <Emphasis Type="Italic">Cedrela odorata</Emphasis> seedlings in tropical dry agroecosystems

Cedrela odorata (Spanish cedar) is a valuable multi-purpose tree which Central American rural communities and farmers give priority to introducing in pastures and home gardens. In order to propose realistic methods for C. odorata production in local nurseries in the dry tropical region of Nicaragua, we studied: (a) the ability of locally collected C. odorata seeds to germinate, (b) seed response to storage under ambient conditions or under cold storage, (c) the effects of irradiance and watering during cultivation on seedling morphology and post-transplantation survival, and (d) the effects of competition from grasses on C. odorata seedlings transplanted to pastures. Seed germination ranged from 55 to 66% and remained constant after 6 months of storage under ambient conditions or cold storage. C. odorata seedling morphology was sensitive to irradiation and watering in the nursery growing period. Deep shade reduced seedling biomass and leafiness and increased specific leaf area and root-to-shoot ratio. Water shortage increased root mass ratio and root-to-shoot ratio and decreased leaf mass ratio. Post-transplantation success was favored by weeding, and was the highest for seedlings grown under deep shade and water restrictions.     

Effect of thermal treatments on the chemical and biological value of irradiated and non-irradiated cowpea bean (Vigna unguiculata L. Walp) flour

Chemical and nutritional characteristics of irradiated and nonirradiated cowpea bean at 0.2 kGy submitted to several thermal treatments were studied. The cowpea bean flours irradiated at 0.2 kGy were superior to those non-irradiated concerning digestibility and the flours submitted to microwave oven were superior to those cooked under low pressure, autoclaved or even raw from the nutritional point of view. As to the presence of anti-nutritional factors, the results showed that the variety of cowpea bean under research presented neither trypsin inhibitor nor haemagglutinin activity, however, regarding tannin, a 0.006% content was found and considered negligible.     

Immunological analysis of serum for buckwheat fed celiac patients

Buckwheat (Fagopyrum esculentum, Moench), a herbaceous plant of the Polygonaceae family, does not have any affinity for the Gramineae family. It is commercially rated as a cereal, which has led to some misunderstanding concerning its use in gluten induced enteropathy or celiac disease. The effect of buckwheat flour ingestion by celiac patients was evaluated through the indirect immunofluorescence technique. Samples of serum were collected 30 days after the flour ingestion. Cryostat performed cuts of wheat and buckwheat grains were accomplished in order to compare the reactivity of their proteins and serum of celiac and normal patients. The assay revealed that the buckwheat flour presents no toxicity for the celiac patient and no anti-protein antibodies formation in the grain was observed for serum dilutions of 1:2 up to 1:32 with 0.15 M NaCl solution in 0.01 M phosphate buffer, pH 7.2 throughout the 30 day assay period. The results of the immunological assays showed that the buckwheat flour does not present toxic prolamines to celiac disease patients.     

Thiamethoxam is a neonicotinoid precursor converted to clothianidin in insects and plants

Neonicotinoid insecticides are compounds acting agonistically on insect nicotinic acetylcholine receptors (nAChR). They are especially active on hemipteran pest species such as aphids, whiteflies, and planthoppers, but also commercialized to control many coleopteran and some lepidopteran pest species. The most prominent member of this class of insecticides is imidacloprid. All neonicotinoid insecticides bind with high affinity (I₅₀-values around 1 nM) to [³H]imidacloprid binding sites on insect nAChRs. One notable ommission is the neonicotinoid thiamethoxam, showing binding affinities up to 10,000-fold less potent than the others, using housefly head membrane preparations. Electrophysiological whole cell voltage clamp studies using neurons isolated from Heliothis virescens ventral nerve cord showed no response to thiamethoxam when applied at concentrations of 0.3 mM, although the symptomology of poisoning in orally and topically treated noctuid larvae suggested strong neurotoxicity. Other neonicotinoids, such as clothianidin, exhibited high activity as agonists on isolated neurons at concentrations as low as 30 nM. There was no obvious correlation between biological efficacy of thiamethoxam against aphids and lepidopterans and receptor affinity in electrophysiological and binding assays. Pharmacokinetic studies using an LC-MS/MS approach to analyze haemolymph samples taken from lepidopteran larvae revealed that thiamethoxam orally applied to 5th instar Spodoptera frugiperda larvae was rapidly metabolized to clothianidin, an open-chain neonicotinoid. Clothianidin shows high affinity to nAChRs in both binding assays and whole cell voltage clamp studies. When applied to cotton plants, thiamethoxam was also quickly metabolized, with clothianidin being the predominant neonicotinoid in planta briefly after application, as indicated by LC-MS/MS analyses. Interestingly, the N-desmethylated derivative of thiamethoxam, N-desmethyl thiamethoxam, was not significantly produced in either lepidopteran larvae or in cotton plants, although it was often mentioned as a possible metabolite, being nearly as active as imidacloprid. In conclusion, our investigations show that thiamethoxam is likely to be a neonicotinoid precursor for clothianidin.     

Oats (Avena strigosa) as winter forage for dairy cows in Vietnam: an on-farm study

In North Vietnam, during winter, alternative forage resources are needed to balance the feed ration of dairy cows. The objective of this study was to investigate the effect of oat forage as a component of traditional winter roughage diets on feed intake, milk production and feeding cost in dairy cows. The study was conducted on-farm using 24 mid-lactation Holstein–Friesian cows. The feeding experiment consisted of two successive periods and two dietary treatments per period. Traditional basal diets included fresh tropical grasses, maize silage and hay. The oat forage had no effect on the dry matter intake of the basal diet, but the total crude protein intake was higher in cows fed with oat diets than in those fed with control diets. The yield of butterfat-corrected milk (FCM) was not significantly different between diets during period 1, but there was a trend (P?=?0.078) of higher FCM yields in cows fed with the oat diet compared to those with control diet during period 2 (17.3 vs. 16.3 kg/day). The decline rate in milk yield was significantly higher (P?<?0.001) in cows fed with control diets than in those fed with oat diets in both experimental periods. The total feeding cost of cows fed with oat diets was on average 12 % lower than those fed with control diets (P?<?0.01). So, the oat forage is an important winter resource for cows in North Vietnam allowing higher milk yield whilst reducing feeding cost, compared to traditional roughage diets.     

The novel pyridazine pyrazolecarboxamide insecticide dimpropyridaz inhibits chordotonal organ function upstream of TRPV channels

The cover image is based on the Research Article The novel pyridazine pyrazolecarboxamide insecticide dimpropyridaz inhibits chordotonal organ function upstream of TRPV channels by Christian Spalthoff et al., https://doi.org/10.1002/ps.7352