The lack of efficient methods to control the major diseases of crops most important to agriculture leads to huge economic losses and seriously threatens global food security. Many of the most important microbial plant pathogens, including bacteria, fungi, and oomycetes, secrete necrosis- and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs), which critically contribute to the virulence and spread of the disease. NLPs are cytotoxic to eudicot plants, as they disturb the plant plasma membrane by binding to specific plant membrane sphingolipid receptors. Their pivotal role in plant infection and broad taxonomic distribution makes NLPs a promising target for the development of novel phytopharmaceutical compounds. To identify compounds that bind to NLPs from the oomycetesPythium aphanidermatumandPhytophthora parasitica, a library of 587 small molecules, most of which are commercially unavailable, was screened by surface plasmon resonance. Importantly, compounds that exhibited the highest affinity to NLPs were also found to inhibit NLP-mediated necrosis in tobacco leaves andPhytophthora infestansgrowth on potato leaves. Saturation transfer difference-nuclear magnetic resonance and molecular modelling of the most promising compound, anthranilic acid derivative, confirmed stable binding to the NLP protein, which resulted in decreased necrotic activity and reduced ion leakage from tobacco leaves. We, therefore, confirmed that NLPs are an appealing target for the development of novel phytopharmaceutical agents and strategies, which aim to directly interfere with the function of these major microbial virulence factors. The compounds identified in this study represent lead structures for further optimization and antimicrobial product development.
Much biomedical research focuses on the effects of UV light on human cells. UV light sources are a prerequisite for such research. This paper presents the design and achieved performance of a UVA (Ultraviolet A: 320–400 nm) and a UVB (Ultraviolet B: 290–320 nm) LED-based lamp suitable for use in bioassays, as well as inside an incubator. Numerical simulations were used to optimise the number, layout and output power of LEDs to achieve good irradiance homogeneity while maintaining low costs. Design was optimised for the efficient transfer of generated heat away from the irradiated samples through the heatsink at the back of the lamps. The average irradiance of the target surface by the UVA lamp was 70.1 W/m2 with a maximum deviation of 4.9%, and the average irradiance by the UVB lamp was 3.1 W/m2 with a maximum deviation of 4.8%. With the UVA and UVB lamps, the temperature of samples undergoing irradiation in the incubator rises from 37 to 42 °C within 40 and 67 min, respectively. This by far exceeds the required UV irradiation time in most cases. Tests on Jurkat and HEK-293 cell cultures confirmed the suitability of our lamps for biomedical research.
A major drawback of the IgG capture step is the high cost of the protein A resin. For a better utilization of the resin, a continuous multi-column operation was recently proposed. In this method, accurate detection of leaking IgG is crucial to divert the breakthrough fluid from the waste to the next column and prolong the loading step without product loss. The detection of a breakthrough point as a change in UV absorption is based on a relatively small signal addition of IgGs to the bulk signal of host cell proteins. To achieve specificity, we used a quartz crystal microbalance and immobilized protein A as specific ligand on the sensor surface. We integrated the quartz crystal microbalance sensor in-line after the protein A column for real-time detection of IgGs in the breakthrough fluid. We show that this specific IgG detection in the breakthrough fluid can be more sensitive than with the UV detector. The use of the same product-specific ligand in the affinity column and in the sensor allows simultaneous in-line regeneration of column and sensor in a single step. Such a sensor could support cost-efficient load control during the entire continuous multi-column capture step in downstream processing.
Amphibole asbestos is related to multiple diseases, mainly those targeting the lungs. Asbestos-related malignancies can also be caused by non-regulated asbestiform minerals and some elongated mineral particles (EMPs). In particular, the role of nano- and micro-sized EMPs internalized by lung epithelial cells must be clarified. This is of major importance when considering that EMPs to which humans are exposed are likely a highly heterogeneous mix of different mineral types, shapes, and sizes. Here, we document that particles smaller than 4.54 µm in length and smaller than 0.89 µm in width (e.g., particles that do not fit the regulatory categories to be identified as asbestos) are easily internalized because of their specific dimensions, surface charge, and shape (mostly dictated by the aspect ratio L/w). Once internalized, these particles can be found in proximity to the cell nucleus, in vesicles, and in the cytoplasm. Examining the localization of particles in cells provides important information, which helps in determining the physicochemical environment found inside the biological compartment, thus allowing for a better comprehension of the mineralogical transformation that might happen after internalization by cells.
Cone snails are a large group of marine gastropods that produce a complex mixture of toxic compounds to hunt prey and defend against predators. The majority of the venom comprises small toxic peptides named conotoxins, which target membrane receptors. In contrast, a smaller part of the venom contains larger proteins and conoproteins, which are thought to be involved in conotoxin maturation and the envenomation process, respectively. Interestingly, many species of cone snails contain conoporins, which are similar to actinoporins—pore-forming toxins found in sea anemones. These actinoporin-like proteins (ALPs) have recently been detected in many molluscan species, and only a few have been experimentally characterized. Due to being highly expressed in the venom gland of many cone snail species, conoporins are thought to play an important part in the envenomation process. Despite this, the exact function of conoporins is currently unknown. We propose several hypotheses aiming to elucidate their biological role.