Relationship between the age of Vespa velutina workers and their defensive behaviour established from colonies maintained in the laboratory

As the structural bases of insect societies are essential to colony survival, nests must be protected from predation. Nest defence behaviours are among the most important roles assigned to worker members. However, in hornet societies, temporal polyethism (age-dependent division of labour among workers) is assumed to be weak. Few studies have investigated this phenomenon, probably because hornet nests are aggressively defended and dangerous to approach. In the present study, we propose a method for rearing nests of Vespa velutina, a species newly introduced into Europe. This method enables the handling of hornets, and thus the design of experiments. By marking all newly emerged hornets, we recorded aggressiveness in workers of different ages from three captive colonies. We observed that nest defence behaviour in V. velutina depends on the age of the workers. Nest defence appears to be mediated by the queen, probably through pheromones that promote nest organization. We also identified a previously unreported but important behaviour in V. velutina that workers are aggressive towards male hornets. This behaviour might be a strategy to avoid inbreeding. Collectively, our results provide new research perspectives for the management of social hymenopteran predators.     

The persistence of biofilm-associated antibiotic resistance of Staphylococcus aureus isolated from clinical bovine mastitis cases in Australia

The aim of this investigation was to determine the persistence of biofilm-associated antibiotic resistance developed by methicillin-sensitive Staphylococcus aureus (MSSA), of different capsular types, during biofilm formation. Because of superiority of the tissue culture plate (TCP) over the Congo Red Agar (CRA) method for measuring biofilm formation, it was used to determine the persistence of the antibiotic resistance developed by the isolates in biofilms. The antibiotic resistance was found to persist for 3–4 wk post-propagation as planktonic subcultures. Interestingly, some strains even developed resistance to vancomycin and/or teicoplanin. However, no association of either biofilm formation or persistent antibiotic resistance with the major capsular phenotype was observed. These observations highlight the potential significance of (a) determining the antibiograms of S. aureus subcultured from biofilms developed in vitro using the TCP method as well as from planktonic cultures for formulation of an optimal therapeutic strategy, and (b) continuing to identify predominant non-capsular antigens contributing to biofilm formation, regardless of the capsular phenotype for the development of an effective potentially broad-spectrum vaccine for prevention of bovine mastitis caused by S. aureus.     

Synthesis and anti-inflammatory activity of aromatic glucosinolates

Aromatic GLs are important members of the glucosinolate family of compounds because of their potential biological activity and medicinal properties. This study has shown success in the high yielding synthesis of some important aromatic GLs as well as the results of testing for anti-inflammatory properties of the synthetic GLs. 3,4-Dimethoxyphenylglucosinolate was found to be the most active anti-inflammatory of the seven glucosinolates assayed.     

Inheritance of human fingerprints]

Polygenic threshold model of finger dermatoglyphics inheritance is worked out on the basis of family and population data. According to the model, ulnar loops are subthreshold patterns, which transforms into whorl or arch under the control of SU and SR gene complexes. Epistasis-hypostasis interactions take place between genes of SU and SR complexes. Classification of phenotypes for finger dermatoglyphics is offered and the frequency of these phenotypes in three populational samples of Kiev is studied.     

Seasonal changes in growth rate, carrageenan yield and lectin content in the red alga Kappaphycus alvarezii cultivated in Camranh Bay, Vietnam

The three color morphotypes of the red alga Kappaphycus alvarezii (brown, red and green) were cultured in Camranh Bay, Vietnam, using the fixed off-bottom monoline culture method to evaluate the growth rate, carrageenan yield, 3,6-anhydrogalactose, gel strength and lectin content. The brown morphotype was cultivated over a 12-month period; the red and green morphotypes were over a 6-month period. At the 60-day culture timepoint, the brown morphotype showed a higher growth rate (3.5–4.6% day⁻¹) from September to February, and lower growth rate (1.6–2.8% day⁻¹) from March to August. Significant (P < 0.05) differences in growth rate between culture months were found with the brown morphotype. High growth rates for the red (3.6–4.4% day⁻¹) and green (3.7–4.2% day⁻¹) morphotypes were obtained from September to February. The carrageenan yield, 3,6-anhydrogalactose and gel strength of the three morphotypes showed little variation, with the highest values obtained in November–December. At the 30-day sampling point, the brown morphotype had a higher lectin content (167–302 μg g⁻¹ dry alga) from August to March and a lower lectin content (23–104 μg g⁻¹ dry alga) from April to July. High lectin contents were recorded for the red (139–338 μg g⁻¹ dry alga) and green (124–259 μg g⁻¹ dry alga) morphotypes from September to February. This study shows that the different morphotypes of K. alvarezii can be grown in the tropical waters of the Camranh during the northeast monsoon, and part of the southwest monsoon, especially the brown morphotype, which can be grown during any season.     

Multilocus nuclear DNA markers reveal population structure and demography of Anopheles minimus

Utilization of multiple putatively neutral DNA markers for inferring evolutionary history of species population is considered to be the most robust approach. Molecular population genetic studies have been conducted in many species of Anopheles genus, but studies based on single nucleotide polymorphism (SNP) data are still very scarce. Anopheles minimus is one of the principal malaria vectors of Southeast (SE) Asia including the Northeastern (NE) India. Although population genetic studies with mitochondrial genetic variation data have been utilized to infer phylogeography of the SE Asian populations of this species, limited information on the population structure and demography of Indian An. minimus is available. We herewith have developed multilocus nuclear genetic approach with SNP markers located in X chromosome of An. minimus in eight Indian and two SE Asian population samples (121 individual mosquitoes in total) to infer population history and test several hypotheses on the phylogeography of this species. While the Thai population sample of An. minimus presented the highest nucleotide diversity, majority of the Indian samples were also fairly diverse. In general, An. minimus populations were moderately substructured in the distribution range covering SE Asia and NE India, largely falling under three distinct genetic clusters. Moreover, demographic expansion events could be detected in the majority of the presently studied populations of An. minimus. Additional DNA sequencing of the mitochondrial COII region in a subset of the samples (40 individual mosquitoes) corroborated the existing hypothesis of Indian An. minimus falling under the earlier reported mitochondrial lineage B.     

Constituents of the leaves of Pseuderanthemum carruthersii (Seem.) Guill. var. atropurpureum (Bull.) Fosb.

A new iridoid, 5β,6β-dihydroxyantirrhide (1) was isolated from the dried leaves of Pseuderanthemum carruthersii (Seem.) Guill. var. atropurpureum (Bull.) Fosb. (Acanthaceae), together with 13 known compounds, including two iridoids, linarioside and antirrhinoside; five phenylethanoids, echipuroside A, verbascoside, isoverbascoside, isomartynoside and osmanthuside B; and six flavonoids, luteolin 7-O-β-d-glucopyranoside, luteolin 7-O-rutinoside, apigenin 7-O-rutinoside, apigenin 6-C-α-l-arabinopyranosyl–8-C-β-l-arabinopyranoside, apigenin 6,8-di-C-α-l-arabinopyranoside and apigenin 6-C-β-d-xylopyranosyl–8-C-α-l-arabinopyranoside. Their chemical structures were elucidated by 1D and 2D NMR as well as HR-ESI-MS spectroscopic analysis. Some purified compounds were evaluated the acetylcholinesterase inhibition and cytotoxic activities against the HeLa cervical cancer cell line and the MCF-7 breast cancer cell line at the concentration of 100 μg/mL. Luteolin 7-O-β-d-glucopyranoside exhibited cytotoxic activities against both the HeLa cervical cancer cell line and the MCF-7 breast cancer cell line. Verbascoside and isoverbascoside showed strong cytotoxic activity against the MCF-7 breast cancer cell line. The tested compounds showed the AChE inhibitory activity fairly weak.     

In Situ Dynamics and Spatial Heterogeneity of Soil Bacterial Communities Under Different Crop Residue Management

The effect of the location of wheat residues (soil surface vs. incorporated in soil) on their decomposition and on soil bacterial communities was investigated by the means of a field experiment. Bacterial-automated ribosomal intergenic spacer analysis of DNA extracts from residues, detritusphere (soil adjacent to residues), and bulk soil evidenced that residues constitute the zone of maximal changes in bacterial composition. However, the location of the residues influenced greatly their decomposition and the dynamics of the colonizing bacterial communities. Sequencing of 16S rRNA gene in DNA extracts from the residues at the early, middle, and late stages of degradation confirmed the difference of composition of the bacterial community according to the location. Bacteria belonging to the γ-subgroup of proteobacteria were stimulated when residues were incorporated whereas the α-subgroup was stimulated when residues were left at the soil surface. Moreover, Actinobacteria were more represented when residues were left at the soil surface. According to the ecological attributes of the populations identified, our results suggested that climatic fluctuations at the soil surface select populations harboring enhanced catabolic and/or survival capacities whereas residues characteristics likely constitute the main determinant of the composition of the bacterial community colonizing incorporated residues.     

Rhizobacterially induced protection of watermelon against Didymella bryoniae

Aims: To identify rhizobacteria from the Mekong Delta of Vietnam, which can systemically protect watermelon against Didymella bryoniae and elucidate the mechanisms involved in the protection conferred by isolate Pseudomonas aeruginosa 23_1‐1. Methods and Results: Bacteria were isolated from watermelon roots and their antagonistic ability tested in vitro. Of 190 strains, 68 were able to inhibit D. bryoniae by production of antibiotics. Four strains were able to reduce foliar infection by D. bryoniae when applied to watermelon seeds before sowing. Strain Ps. aeruginosa 23_1‐1 was chosen for investigations of the mechanisms involved in protection and ability to control disease under field conditions. In the field, the bacterium was able to significantly reduce disease in two consecutive seasons and increase yield. Furthermore, it colonized watermelon plants endophytically, with higher numbers in plants infected by D. bryoniae than in noninoculated plants. To elucidate the mechanisms involved in protection, the infection biology of the pathogen was studied in bacterially treated and control plants. Pseudomonas aeruginosa 23_1‐1 treatment inhibited pathogen penetration and this was associated with hydrogen peroxide accumulation, increased peroxidase activity and occurrence of new peroxidase isoforms, thus indicating that resistance was induced. Conclusions: The endophytic bacterium Ps. aeruginosa 23_1‐1 can control D. bryoniae in watermelon by antibiosis and induced resistance under greenhouse and field conditions. Significance and Impact of the Study: These findings suggest that rhizobacteria from native soils in Vietnam can be used to control gummy stem blight of watermelon through various mechanisms including induction of resistance.