Communication between individuals via molecules, termed chemosignaling, is widespread among animal and plant species. However, we lack knowledge on the specific functions of the substances involved for most systems. The femoral gland is an organ that secretes a waxy substance involved in chemical communication in lizards. While the lipids and volatile substances secreted by the femoral glands have been investigated in several biochemical studies, the protein composition and functions of secretions remain completely unknown. Applying a proteomic approach, we provide the first attempt to comprehensively characterize the protein composition of femoral gland secretions from the Galápagos marine iguana. Using samples from several organs, the marine iguana proteome was assembled by next-generation sequencing and mass spectrometry, resulting in 7,513 proteins. Of these, 4,305 proteins were present in the femoral gland, including keratins, small serum proteins, and fatty acid-binding proteins. Surprisingly, no proteins with discernible roles in partner recognition or inter-species communication could be identified. However, we did find several proteins with direct associations to the innate immune system, including lysozyme C, antileukoproteinase (ALP), pulmonary surfactant protein (SFTPD), and galectin (LGALS1) suggesting that the femoral glands function as an important barrier to infection. Furthermore, we report several novel anti-microbial peptides from the femoral glands that show similar action against Escherichia coli and Bacillus subtilis such as oncocin, a peptide known for its effectiveness against Gram-negative pathogens. This proteomics dataset is a valuable resource for future functional protein analysis and demonstrates that femoral gland secretions also perform functions of the innate immune system.
We report the use of antimicrobial hemolymph proteins from the model host Galleria mellonella as an inhibitor for various Listeria strains, providing a novel source for antilisterial therapeutics. We also have shown that specific virulence-associated genes known to mediate antimicrobial resistance of Listeria in mammalian models indicated a similar function in Galleria.
Many corrosion problems are caused by the presence of microorganisms, so-called microbiologically influenced corrosion (MIC). A major representative of MIC-causing bacteria includes the group of sulfate-reducing bacteria (SRB), which accumulate in biofilms on the surface. Removal of biofilm inhabiting bacteria is much more complex compared to planktonic cell removal, in particular, based on the formation of an extracellular polymeric substance matrix (EPS layer). Current control strategies mainly involve the use of biocides. The development of resistance is a major problem caused by the limited number of suitable biocides and their frequent use. A consequence is a requirement of even elevated concentrations, which in worst-case scenarios results in a complete loss of efficacy. Recently, the use of antimicrobial peptides (AMPs) especially in the field of medical devices has been distinguished, including the coating of implants with AMPs for retarding or even completely preventing biofilm formation. Transferring AMPs to technical applications as MIC controlling agents offers high potential, therefore. However, based on open circuits, e.g. MIC on ship trunks or in wastewater pipes, immobilization of AMPs on surfaces is quite important, while keeping the AMPs active. This article presents various immobilization strategies established for this purpose, with a special focus on covalent AMP immobilization on metal surfaces. Graphical abstract
cHuman adenovirus type 5 (HAdV5) E4orf6 (early region 4 open reading frame 6 protein) is a multifunctional early viral protein promoting efficient replication and progeny production. E4orf6 complexes with E1B-55K to assemble cellular proteins into a functional E3 ubiquitin ligase complex that not only mediates proteasomal degradation of host cell substrates but also facilitates export of viral late mRNA to promote efficient viral protein expression and host cell shutoff. Recent findings defined the role of E4orf6 in RNA splicing independent of E1B-55K binding. To reveal further functions of the early viral protein in infected cells, we used a yeast two-hybrid system and identified the homeobox transcription factor HoxB7 as a novel E4orf6-associated protein.Using a HoxB7 knockdown cell line, we observed a positive role of HoxB7 in adenoviral replication. Our experiments demonstrate that the absence of HoxB7 leads to inefficient viral progeny production, as HAdV5 gene expression is highly regulated by HoxB7-mediated activation of various adenoviral promoters. We have thus identified a novel role of E4orf6 in HAdV5 gene transcription via regulation of homeobox protein-dependent modulation of viral promoter activity. Human adenovirus type 5 (HAdV5) E4orf6 (early region 4 open reading frame 6 protein) is a multifunctional protein which promotes efficient viral replication and plays a major role in adenoviral transformation processes. During infection, this viral factor assembles an SCF-like E3 ubiquitin ligase complex based on the cellular proteins elongins B and C, cullin 5, and Rbx1 (4, 66; reviewed in references 74 and 83). In cooperation with E1B-55K (early region 1B 55K protein), this viral RING-type ligase ubiquitinates cellular substrates prior to proteasomal degradation. So far, p53, DNA ligase IV, Mre11, integrin ␣3, and BLM (Blooms helicase) have been identified as targets of this HAdV5 ligase complex (4,18,64,83).E1B-55K was also identified as a viral interaction partner of the transcription factor Daxx (76,79,89) and is required for proteasomal degradation of Daxx during HAdV5 infection (75, 76). Remarkably, in contrast to the cellular targets of HAdV5 E3 ubiquitin ligases mentioned above, E4orf6 is dispensable for Daxx removal. In reverse, the HAdV12 E4orf6 protein was shown to target TopBP1, a protein involved in the DNA damage response and cell cycle checkpoint control (70, 71). In this case, HAdV12 E1B-55K is apparently not relevant for the cullin2-E4orf6-dependent proteasomal degradation of TopBP1 (5). In addition, it was shown that formation of the HAdV5 E3 ubiquitin ligase complex is necessary for E4orf6-and E1B-55K-mediated export of viral late mRNA out of the nucleus into the cytoplasm (7, 88). This preferential export of viral transcripts over cellular mRNA is important for efficient viral protein expression and host cell shutoff.However, different studies show that during the course of infection, only up to 50% of E4orf6 is associated with E1B-55K (16,60,80). Therefore, we were interested in ad...
Microbiologically influenced corrosion is a common problem in the industrial field due to the deterioration of metals in the presence of various microorganisms, in particular sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB). A common method to reduce microbiologically influenced corrosion is the application of biocides. The limited number of suitable biocides and the resulting development of resistance, high dosage, and high application rate hinder an effective application. An environmentally friendly alternative could be the application of antimicrobial peptides (AMP), which have already been established in the field of medical devices for a while. Here, the successful treatment of different AMPs against 3 SRB and 1 SOB was demonstrated. The peptide L5K5W was favored due to its broad activity, high stability, and simple structure resulting in low synthesis costs. An alanine scan showed that substitution of leucine with tryptophan increased the activity of this peptide twofold compared to the original peptide against D. vulgaris, the main representative of SRB. Additional optimization of this modified peptide through changes in amino acid composition and lipidations significantly increased the effectiveness, finally resulting in a minimum inhibitory concentration (MIC) of 15.63 μg/mL against Desulfovibrio vulgaris. Even against the marine SRB Desulfovibrio indonesiensis with a required salt concentration of min. 2%, an activity of the peptides can be observed (MIC: 31.25 μg/mL). The peptides also remained stable and active for 7 days in the supernatant of the bacterial culture. Key points • Antimicrobial peptides provide an alternative to combat biocorrosive bacteria. • Optimization of the peptide sequence leads to a significant increase in activity. • The investigated peptides exhibit high stability, both in the medium and in the bacterial supernatant. Graphical abstract
Biofilms and their analysis are increasingly attracting the attention of the scientific community due to the immense importance and impact of biofilms in various natural, technical and medical fields. For these purposes, an optimized and extended antibiofilm assay system based on the Calgary Biofilm Device (MBEC Assay® system) consisting of microtiter plate and PCR tubes was established. Its implementation was used to study the growth characteristics of the sessile phenotype of Pseudomonas fluorescens exposed to antimicrobial peptides. Inhibitory effects of an antimicrobial peptide on P. fluorescens biofilm formation could be determined at a concentration of 250 μg/ml (biofilm prevention concentration (BPC)) using the modified biofilm assay. Similarly, the biofilm bactericidal concentration (BBC) at 125 μg/ml and the minimum biofilm elimination concentration to remove 90% of the total biofilm mass (MBEC90) were measured at a concentration range of 15.625–1.95 μg/ml. In conclusion, this optimized system provides a highly variable, simple, and cost‐effective alternative to high‐throughput screening based on the Calgary Biofilm Device (CBD).
Peptides are compounds involved in a wide variety of biological roles. Their advantages depend on the strategy applied to produce them and include biocompatibility, low cost, tunable bioactivity, chemical variety, and specific targeting. Consequently, they are able to serve an enormous range of biotechnology and pharmaceutical applications. Including topics ranging from bio-based adhesives to peptide nanosystems for active delivery of drugs to specific biological targets
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