The gut and feed residue microbiota changing during the rearing of Hermetia illucens larvae.

Larvae of Hermetia illucens, commonly known as black soldier fly, efficiently convert organic waste into nutrient-rich supplements for different applications. Here we performed a preliminary experiment to investigate the dynamics of the H. illucens gut microbiota and changes in the composition of the bacterial community in the residue of the larval feed during rearing. We furthermore quantified the presence of antibiotic resistance and disinfectant genes in the gut and feed microbiota during the rearing process to elucidate if rearing leads to a reduction, increase, and/or transfer of resistance genes from the feed to larvae and vice versa. We found that the gut and feed residue bacterial communities were distinct throughout the rearing process. The gut microbiome remained more stable compared to the feed residue microbiome varying in both bacterial abundance and community structure during rearing. Antibiotic-resistance genes were present in both, gut and feed residues, with a significant increase in pupae and residue samples taken at the end of the rearing process. Disinfectant-resistance genes were present in the feed residue and even increased during the rearing process but were not transferred to the gut microbiome. We conclude that H. illucens larvae have a stable gut microbiome that does not change significantly over the course of larval development, whereas bacterial communities in the feed residue are strongly affected by rearing. If the presence of antibiotics and disinfectants during rearing, can promote the spread of antibiotic/disinfectant-resistance genes among feed and larvae needs to be evaluated in further experiments.

Automated thin-film microextraction coupled to a flow-through cell: somewhere in between passive and active sampling.

A prototype for the automated thin-film microextraction of pharmaceuticals from aqueous solutions has been developed and is presented here for the first time. With a software-controlled setup, extraction methods for ivermectin and iohexol have been developed. The widely used antiparasitic agent ivermectin is non-polar and has a high tendency to sorb to surfaces. In contrast to this, the nonionic but polar iodinated X-ray contrast agent iohexol is freely water soluble. With these two substances, a wide range of polarity is covered. Sorption kinetics and thermodynamics of ivermectin and iohexol were studied. With the presented passive sampling approach, it was possible to extract up to 96.2% ivermectin with a C18-phase within 1 h and up to 74.6% of iohexol with a PS-DVB phase within 36 h out of water. Using abamectin as internal standard, it was possible to quantitatively follow dissipation of ivermectin in a simulated surface water experiment. Predominantly, the newly developed prototype can be used for automated and time-resolved extraction of xenobiotics from waterbodies under field conditions, for the extraction of substances under laboratory conditions as an alternative to the elaborate solid-phase extraction, and for the automated control of chemical reaction kinetics.

Endophytic bacterial communities of oilseed rape associate with genotype-specific resistance against Verticillium longisporum.

Associations of endophytic bacterial community composition of oilseed rape (Brassica napus L.) with quantitative resistance against the soil-borne fungal pathogen Verticillium longisporum was assessed by 16S rRNA gene amplicon sequencing in roots and hypocotyls of four plant lines with contrasting genetic composition in regard to quantitative resistance reactions. The plant compartment was found to be the dominating driving factor for the specificity of bacterial communities in healthy plants. Furthermore, V. longisporum infection triggered a stabilization of phylogenetic group abundance in replicated samples suggesting a host genotype-specific selection. Genotype-specific associations with bacterial phylogenetic group abundance were identified by comparison of plant genotype groups (resistant versus susceptible) and treatment groups (healthy versus V. longisporum-infected) allowing dissection into constitutive and induced directional association patterns. Relative abundance of Flavobacteria, Pseudomonas, Rhizobium and Cellvibrio was associated with resistance/susceptibility. Relative abundance of Flavobacteria and Cellvibrio was increased in resistant genotypes according to their known ecological functions. In contrast, a higher relative abundance of Pseudomonas and Rhizobium, which are known to harbor many species with antagonistic properties to fungal pathogens, was found to be associated with susceptibility, indicating that these groups do not play a major role in genetically controlled resistance of oilseed rape against V. longisporum.

Parendozoicomonas haliclonae gen. nov. sp. nov. isolated from a marine sponge of the genus Haliclona and description of the family Endozoicomonadaceae fam. nov. comprising the genera Endozoicomonas, Parendozoicomonas, and Kistimonas.

Two Gram-stain-negative, facultative anaerobic, motile, rod-shaped strains, S-B4-1UT and JOB-63a, forming small whitish transparent colonies on marine agar, were isolated from a sponge of the genus Haliclona. The strains shared 99.7% 16S rRNA gene sequence identity and a DNA-DNA hybridization value of 100%, but were differentiated by genomic fingerprinting using rep-PCRs. 16S rRNA gene sequence phylogeny placed the strains as a sister branch to the monophyletic genus Endozoicomonas (Oceanospirillales; Gammaproteobacteria) with 92.3-94.3% 16S rRNA gene sequence similarity to Endozoicomonas spp., 91.9 and 92.1% to Candidatus Endonucleobacter bathymodiolin, and 91.9 to 92.1% to the type strains of Kistimonas spp. Core genome based phylogeny of strain S-B4-1UT confirmed the phylogenetic placement. Major fatty acids were summed feature 3 (C16:1 ω7c/C16:1 ω6c) and 8 (C18:1 ω7c/C18:1 ω6c) followed by C10:0 3-OH, C16:0, and C18:0. The G+C content was 50.1-51.4mol%. The peptidoglycan diamino acid of strain S-B4-1UT was meso-diaminopimelic acid, the predominant polyamine spermidine, the major respiratory quinone ubiquinone Q-9; phosphatidylethanolamine, phosphatidylglycerol and phosphatidylserine were major polar lipids. Based on the clear phylogenetic distinction, the genus Parendozoicomonas gen. nov. is proposed, with Parendozoicomonas haliclonae sp. nov. as type species and strain S-B4-1UT (=CCM 8713T=DSM 103671T=LMG 29769T) as type strain and JOB-63a as a second strain of the species. Based on the 16S rRNA gene sequence phylogeny of the Oceanospirillales within the Gammaproteobacteria, the Endozoicomonaceae fam. nov. is proposed including the genera Endozoicomonas, Parendozoicomonas, and Kistimonas as well as the Candidatus genus Endonucleobacter.