Plectin ensures intestinal epithelial integrity and protects colon against colitis

Plectin, a highly versatile cytolinker protein, provides tissues with mechanical stability through the integration of intermediate filaments (IFs) with cell junctions. Here, we hypothesize that plectin-controlled cytoarchitecture is a critical determinant of the intestinal barrier function and homeostasis. Mice lacking plectin in an intestinal epithelial cell (IEC; PleΔIEC) spontaneously developed colitis characterized by extensive detachment of IECs from the basement membrane (BM), increased intestinal permeability, and inflammatory lesions. Moreover, plectin expression was reduced in the colons of ulcerative colitis (UC) patients and negatively correlated with the severity of colitis. Mechanistically, plectin deficiency in IECs led to aberrant keratin filament (KF) network organization and the formation of dysfunctional hemidesmosomes (HDs) and intercellular junctions. In addition, the hemidesmosomal α6β4 integrin (Itg) receptor showed attenuated association with KFs, and protein profiling revealed prominent downregulation of junctional constituents. Consistent with the effects of plectin loss in the intestinal epithelium, plectin-deficient IECs exhibited remarkably reduced mechanical stability and limited adhesion capacity in vitro. Feeding mice with a low-residue liquid diet that reduced mechanical stress and antibiotic treatment successfully mitigated epithelial damage in the PleΔIEC colon.

An improved method for in vitro feeding of adult female Dermanyssus gallinae (poultry red mite) using Baudruche membrane (goldbeater’s skin)

Background Dermanyssus gallinae, or poultry red mite (PRM), is an important ectoparasite in laying hen, having a significant effect on animal welfare and potentially causing economic loss. Testing novel control compounds typically involves in vitro methodologies before in vivo assessments. Historically, in vitro methods have involved PRM feeding on hen blood through a membrane. The use of hen blood requires multiple procedures (bleeds) to provide sufficient material, and the use of a larger species (e.g. goose) could serve as a refinement in the use of animals in research. Methods The in vitro feeding device used was that which currently employs a Parafilm™ M membrane (Bartley et al.: Int J Parasitol. 45:819–830, 2015). Adult female PMR were used to investigate any differences in mite feeding, egg laying and mortality when fed goose or hen blood. Effects on these parameters when PRM were fed through either the Parafilm™ M membrane or the Baudruche membrane alone or through a combination of the membrane with an overlaid polyester mesh were tested using goose blood. Results Poultry red mites fed equally well on goose or hen blood through the Parafilm™ M membrane, and there were no significant differences in mortality of PRM fed with either blood type. A significant increase (t test: t = 3.467, df = 4, P = 0.03) in the number of eggs laid per fed mite was observed when goose blood was used. A 70% increase in PRM feeding was observed when the mites were fed on goose blood through a Baudruche membrane compared to when they were fed goose blood through the Parafilm™ M membrane. The addition of an overlaid polyester mesh did not improve feeding rates. A significant increase (analysis of variance: F(3, 20) = 3.193, P = 0.04) in PRM egg laying was observed in mites fed on goose blood through the Baudruche membrane compared to those fed goose blood through the Parafilm™ M membrane. A mean of 1.22 (standard error of the mean ± 0.04) eggs per fed mite was obtained using the Baudruche feeding device compared to only 0.87 (SEM ± 0.3) eggs per fed mite using the Parafilm™ M device when neither was combined with a polyester mesh overlay. Conclusion The in vitro feeding of adult female PRM can be readily facilitated through the use of goose blood in feeding devices with the Baudruche membrane.

An improved method for in vitro feeding of adult female Dermanyssus gallinae (poultry red mite) using Baudruche membrane (goldbeater’s skin).

Background Dermanyssus gallinae , or poultry red mite (PRM), is an important ectoparasite in laying hens, having a significant welfare and economic impact. Testing novel control compounds typically involves in vitro methodologies before in vivo assessments. Historically, in vitro methods have involved PRM feeding on hen blood through a membrane. The use of hen blood requires multiple procedures (bleeds) to provide sufficient material and the use of a larger species (e.g. geese), could serve as a refinement in the use of animals in research. Methods The existing in vitro feeding device, employing a Parafilm™ M membrane [1] and adult females was used to investigate any differences in mite feeding, egg laying and mortality when fed goose or hen blood. Effects on these parameters when PRM were fed through either; Parafilm™ M, Baudruche membrane, and a combination of these with an overlaid polyester mesh were then tested using goose blood. Results PRM fed equally well on goose or hen blood through a Parafilm™ M membrane, no significant differences in mortality of PRM fed with either blood type was demonstrated. A significant increase (t-test: t =3.467, df =4, P = 0.03). in eggs laid per fed mite when using goose blood was demonstrated. A 70% increase in PRM feeding was observed when mites were fed on goose blood through a Baudruche membrane when compared to the Parafilm™ M membrane. Addition of an overlaid polyester mesh did not improve feeding rates. A significant increase (ANOVA: F (3, 20) =3.193, P = 0.04) in PRM egg laying was observed in mites fed on goose blood through Baudruche membrane, compared to those fed through Parafilm™ M. A mean of 1.22 (SEM ± 0.04) eggs per fed mite was obtained using the Baudruche feeding device compared to only 0.87 (SEM ±0.3) eggs per fed mite using the Parafilm™ M device when neither had a polyester mesh overlay. Conclusion The in vitro feeding of adult female poultry red mite can be readily facilitated through the use of goose blood in feeding devices with Baudruche membrane.

Putative morphology of Neoehrlichia mikurensis in salivary glands of Ixodes ricinus

Neoehrlichia mikurensis is an emerging tick-borne intracellular pathogen causing neoehrlichiosis. Its putative morphology was described in mammalian, but not in tick cells. In this study, we aim to show the presumptive morphology of N. mikurensis in salivary glands of engorged females of Ixodes ricinus. To accomplish this, we collected I. ricinus ticks in a locality with a high N. mikurensis prevalence, allowed them to feed in the artificial in vitro feeding system, dissected salivary glands and screened them by PCR for N. mikurensis and related bacteria. Ultrathin sections of salivary glands positive for N. mikurensis but negative for other pathogens were prepared and examined by transmission electron microscopy. We observed two individual organisms strongly resembling N. mikurensis in mammalian cells as described previously. Both bacteria were of ovoid shape between 0.5–0.8 μm surrounded by the inner cytoplasmic and the rippled outer membrane separated by an irregular electron-lucent periplasmic space. Detection of N. mikurensis in salivary glands of I. ricinus suggests that this bacterium uses the “salivary pathway of transmission” to infect mammals.

Tick populations from endemic and non-endemic areas in Germany show differential susceptibility to TBEV

Tick-borne encephalitis virus (TBEV) is endemic in twenty-seven European countries, transmitted via the bite of an infected tick. TBEV is the causative agent of one of the most important viral diseases of the central nervous system (CNS). In Germany, 890 human cases were registered between the years 2018–2019. The castor bean tick, Ixodes ricinus, is the TBEV vector with the highest importance in Central Europe, including Germany. Despite the nationwide distribution of this tick species, risk areas of TBEV are largely located in Southern Germany. To increase our understanding of TBEV-tick interactions, we collected ticks from different areas within Germany (Haselmühl/Bavaria, Hanover/Lower Saxony) and infected them via an in vitro feeding system. A TBEV isolate was obtained from an endemic focus in Haselmühl. In two experimental series conducted in 2018 and 2019, ticks sampled in Haselmühl (TBEV focus) showed higher artificial feeding rates, as well as higher TBEV infections rates than ticks from the non-endemic area (Hanover). Other than the tick origin, year and month of the infection experiment as well as co-infection with Borrelia spp., had a significant impact on TBEV Haselmühl infection rates. Taken together, these findings suggest that a specific adaptation of the tick populations to their respective TBEV virus isolates or vice versa, leads to higher TBEV infection rates in those ticks. Furthermore, co-infection with other tick-borne pathogens such as Borrelia spp. can lower TBEV infection rates in specific populations.

An Improved Method for in Vitro Feeding of Dermanyssus Gallinae (Poultry Red Mite) Using Baudruche Membrane (Goldbeater’s Skin).

Background: Dermanyssus gallinae, or poultry red mite (PRM), is one of the most economically important ectoparasites in laying hens worldwide with infestations leading to both welfare and economic issues. Research into the testing and validation of novel vaccines and systemic acaricides to control PRM initially requires the use of in vitro methodologies before using in vivo assessments. In vitro methods to date have either involved PRM feeding on hen blood through biological membranes such as chick skin, which can be difficult to obtain and variable in quality, or through synthetic membranes that are unsatisfactory due to breakage and lack of natural feeding cues. The use of hen blood in these systems also requires multiple procedures (bleeds) to provide sufficient material for experimental replicates and the potential for using other species, from which larger blood volumes can be withdrawn in a single procedure (e.g. geese), could improve this technique as a refinement in the use of animals in research.Methods: Using adult female PRM, an initial experiment with an existing in vitro feeding device employing a Parafilm™ M membrane [1] was used to investigate any differences in mite feeding, egg laying and mortality when fed goose or hen blood. Subsequently, any effects on these parameters when PRM were fed through two different membranes; Parafilm™ M and Baudruche membrane, and a combination of these membranes with an overlaid polyester mesh to promote mite attachment, were then tested using goose blood as the food source.Results: PRM fed equally well on goose or hen blood through a Parafilm™ M membrane and there were no statistically significant differences in mortality of PRM fed with either blood type, although a significant increase (p = 0.03) in eggs laid per fed mite when using goose blood was demonstrated, indicating that goose blood is a satisfactory replacement for hens blood. A 70% increase in PRM feeding was observed when mites were fed on goose blood through a Baudruche membrane when compared to the Parafilm™ M membrane. Addition of an overlaid polyester mesh did not further improve feeding rates on either membrane. A significant increase (p = 0.04) in PRM egg laying was observed in mites fed on goose blood through Baudruche membrane, compared to those fed through Parafilm™ M. A mean of 1.22 eggs per fed mite was obtained using the Baudruche feeding device compared to only 0.87 eggs per fed mite using the Parafilm™ M device when neither had a polyester mesh overlay. It was noted that PRM feeding through Baudruche membrane had fed to repletion when compared to those fed through Parafilm™ M.Conclusion: The in vitro feeding of poultry red mite can be readily facilitated through the use of goose blood in feeding devices with Baudruche membrane.