Can Insects Develop Resistance to Insect Pathogenic Fungi?

This paper presents new, important information on the microevolution of insect resistance to the insect pathogenic fungus Beauveria bassiana which will have far-reaching implications for the development of insect pathogenic fungi as biological control agents. We placed successive generations of a melanic population of the Greater wax moth, Galleria mellonella, under constant selective pressure from the insect pathogenic fungus, Beauveria bassiana. Enhanced fungal resistance was observed and larvae from the 25th generation were studied in detail to uncover mechanisms underpinning resistance, and the possible cost of those survival strategies. There are 3 novel, core findings from the study:1.Antifungal resistance in these insects is pathogen species-specific, and probably arises through trans-generational immune priming. The resistance was less obvious in earlier generations, suggesting subtle cumulative changes that are only fully apparent in the 25th generation. 2.The insect’s fecundity is already pushed close to minimum by its melanic phenotype. Therefore, the additional drain on resources required to boost antifungal defence still more, comes not from further compromising life history traits but via a re-allocation of the insect’s immune defences. Specifically during B. bassiana infection, systemic (fat body and hemocoel) responses, particularly the expression of antimicrobial peptides, are damped down in favour of a tailored repertoire of enhanced responses in the integument (cuticle and epidermis) – the foremost and most important barrier to natural fungal infection. 3.A previously-overlooked range of putative stress-management factors are activated during the specific response of selected insects to B. bassiana. This too occurs primarily in the integument, and contributes to antifungal defense and/or helps ameliorate the damage inflicted by the fungus or the host’s own immune responses during the battle between host and pathogen.No other study to date has examined so many genes in this context. Indeed, we show that the epidermis has a great capacity to express defense and stress-management genes as well as the fat body (which is the main tissue producing antimicrobial peptides and has been the traditional focus of attention). We therefore propose a “be specific / fight locally / de-stress” model to explain resource allocation and defence priorities for insects selected for superior resistance to insect-pathogenic fungi. However, we also show that these insects are less fecund and probably at no evolutionary advantage in the wild, implying that the risk is small of biological control agents failing in the field

Novel Approach Identifies SNPs in SLC2A10 and KCNK9 with Evidence for Parent-of-Origin Effect on Body Mass Index

Marja-Liisa Lokki työryhmien Generation Scotland Consortium, LifeLines Cohort Study ja GIANT Consortium jäsenPeer reviewe

The characteristic of aroma and antioxidant properties of chosen infusions of stimulants and herbs

Celem pracy było porównanie składu związków przeciwutleniających oraz ich aktywności, a także dokonanie charakterystyki składników aromatu popularnych napojów o wysokiej aktywności biologicznej: kaw mielonych i rozpuszczalnej oraz innych naparów: herbaty zielonej, mate, rooibos i fongru. Oznaczono zawartość polifenoli ogółem, ich skład i zawartość kofeiny metodą HPLC, aktywność przeciwutleniającą naparów wobec kationorodników ABTS oraz skład związków lotnych w fazie nadpowierzchniowej metodą SPME-GC-MS. Stwierdzono, że znaczne różnice zawartości związków przeciwutleniających i wynikające z tego różnice aktywności uzyskanych naparów są w dużej mierze efektem różnic w sposobie przygotowywania naparów, gdyż nie są one tak znaczące w przypadku surowców służących do ich sporządzenia. Aktywność przeciwrodnikowa była znacznie większa w herbacie zielonej (250 mg Trolox/g s.m.) i mate (130 mg/g) niż w kawach mielonych (około 50-70 mg/g), podczas gdy kawy zdecydowanie dominowały pod względem aktywności naparów (500-700 mg Trolox/100 ml w kawach, 260 mg/100 ml w herbacie i 120 mg/100 ml w mate). W pracy wykazano ponadto, że badane kawy charakteryzują się większym bogactwem lotnych składników aromatu, szczególnie w stosunku do herbaty zielonej i rooibos (18-19 związków lotnych wobec 2-3 w naparach herbaty i rooibos).The aim of the study was the comparison of antioxidative compounds composition and their activity as well as the accomplishment of aroma constituents of high biologically active popular beverages: ground and soluble coffees and other infusions: green tea, mate, rooibos and fongru. Polyphenols content, their composition and caffeine content by HPLC, antioxidant activity of the infusions towards ABTS cation radicals and volatile compounds composition in the headspace by SPME-GC-MS were determined. It was stated, that considerable differences in antioxidative compounds content and resulting differences in the activity of the infusions obtained are to a large extent an effect of the differences in the infusions preparation way, because they are not such meaningful in case of the scientific material. The antiradical activity was much higher in green tea leaves (250 mg Trolox/g d.w.) and mate (130 mg/g) than in ground coffees (opprox. 50-70 mg/g), whereas coffees definitely predominated taking into consideration the activity of infusions (500-700 mg Trolox/100 ml in coffees, 260 mg/100 ml in tea and 120 mg/100 ml in mate). In the study it was also proved that the coffees investigated are characterised by bigger diversity of volatile aroma compounds, particularly in the relationship to green tea and rooibos (18-19 volatiles towards 2-3 in the infusions of tea and rooibos)

Klebsiella phages representing a novel clade of viruses with an unknown DNA modification and biotechnologically interesting enzymes

Lytic bacteriophages and phage-encoded endolysins (peptidoglycan hydrolases) provide a source for the development of novel antimicrobial strategies. In the present study, we focus on the closely related (96 % DNA sequence identity) environmental myoviruses vB_KpnM_KP15 (KP15) and vB_KpnM_KP27 (KP27) infecting multidrug-resistant Klebsiella pneumoniae and Klebsiella oxytoca strains. Their genome organisation and evolutionary relationship are compared to Enterobacter phage phiEap-3 and Klebsiella phages Matisse and Miro. Due to the shared and distinct evolutionary history of these phages, we propose to create a new phage genus BKp15virus^ within the Tevenvirinae subfamily. In silico genome analysis reveals two unique putative homing endonucleases of KP27 phage, probably involved in unrevealed mechanism of DNA modification and resistance to restriction digestion, resulting in a broader host spectrum. Additionally, we identified in KP15 and KP27 a complete set of lysis genes, containing holin, antiholin, spanin and endolysin. By turbidimetric assays on permeabilized Gram-negative strains, we verified the ability of the KP27 endolysin to destroy the bacterial peptidoglycan. We confirmed high stability, absence of toxicity on a human epithelial cell line and the enzymatic specificity of endolysin, which was found to possess endopeptidase activity, cleaving the peptide stem between L-alanine and D-glutamic acid

Capsule-Targeting Depolymerase, Derived from Klebsiella KP36 Phage, as a Tool for the Development of Anti-Virulent Strategy

The rise of antibiotic-resistant Klebsiella pneumoniae, a leading nosocomial pathogen, prompts the need for alternative therapies. We have identified and characterized a novel depolymerase enzyme encoded by Klebsiella phage KP36 (depoKP36), from the Siphoviridae family. To gain insights into the catalytic and structural features of depoKP36, we have recombinantly produced this protein of 93.4 kDa and showed that it is able to hydrolyze a crude exopolysaccharide of a K. pneumoniae host. Using in vitro and in vivo assays, we found that depoKP36 was also effective against a native capsule of clinical K. pneumoniae strains, representing the K63 type, and significantly inhibited Klebsiella-induced mortality of Galleria mellonella larvae in a time-dependent manner. DepoKP36 did not affect the antibiotic susceptibility of Klebsiella strains. The activity of this enzyme was retained in a broad range of pH values (4.0–7.0) and temperatures (up to 45 °C). Consistently, the circular dichroism (CD) spectroscopy revealed a highly stability with melting transition temperature (Tm) = 65 °C. In contrast to other phage tailspike proteins, this enzyme was susceptible to sodium dodecyl sulfate (SDS) denaturation and proteolytic cleavage. The structural studies in solution showed a trimeric arrangement with a high β-sheet content. Our findings identify depoKP36 as a suitable candidate for the development of new treatments for K. pneumoniae infections