SONNE – International

Fusarium head blight (FHB), caused by Fusarium graminearum, poses a significant threat to wheat production in Ethiopia, causing yield losses of up to 30–70

The LytR-CpsA-Psr (Lcp) family of proteins are highly abundant amongst actinomycetes and Gram-positive bacteria, and known to exist as multiple paralogs in an organism. Several reports demonstrated the essential LcpA to play a crucial role in coupling cell wall teichoic acids (arabinogalactan in mycobacteria) to peptidoglycan, making it an attractive drug target against tuberculosis (TB). However, apart from LcpB that accommodates capsular biosynthesis, role of the non-essential Lcp paralogs in mycobacteria largely remains elusive. Therefore, we made a comprehensive approach in characterizing the role of these non-essential Lcp proteins in mycobacterial cell wall assembly. Additionally, we used homology and interactive models as an alternate approach to X-ray crystallography, to identify hotspot residues for Lcp inhibition and subsequent bactericidal activity. Single and double knockout strains of each of the three Mycolicibacterium smegmatis (M. smegmatis) non-essential lcp genes were generated, out of which ΔlcpBΔlcpC exhibited severely compromised cell envelope with impeding cell division, altered morphology, reduced biofilms, enhanced susceptibility to stress, loss of capsular ⍺-glucans and exposed Galf residues. The higher pyrophosphatase activity of LcpB and LcpC, their interaction in native conditions and reduced AG/PG markers in ΔlcpBΔlcpC, substantiates their role in AG-PG ligation. Higher expression of lcpB/lcpC irrespective of external stress indicates tight regulation and coping mechanism conferred by these two homologs on the mycobacterial cell. Cell wall targeting anti-TB drugs in combination with two Lcp inhibitory compounds, Entrectinib and Sorafenib, proved bactericidal. This study highlights the primary role of LcpB/LcpC alongside LcpA in maintaining structural integrity of the M. smegmatis cell envelope, and combined anti-Lcp drug strategy as a novel approach to inhibit mycobacterial replication.

Since the development of DNA microarrays and later RNA bulk sequencing, testing with statistically independent samples has been the standard method for detecting genes with different transcription patterns. Single-cell assays challenge these assumptions because individual cells are statistically dependent, and all proposed methodologies present mathematical limitations or computational bottlenecks that prevent a seamless integration of data from many cells and patients simultaneously. In this work, we solve this crucial limitation by introducing a Bayesian framework that retrieves the independence structure at the level of individual patients, separating differences across individuals from actual transcriptional differences. Leveraging multi-GPU and variational inference, our approach excels across different experimental designs and scales to analyse over 10 million cells. This framework enables single-cell differential expression analysis that can finally integrate datasets from large clinical cohorts, atlas projects, or drug-response screens with thousands of samples and millions of cells.

HIV-1 escape from neutralizing antibodies, even in the presence of strong host immunity, is associated with variations in envelope proteins that drive antigenic diversification. The virus exploits the error-prone nature of reverse transcriptase, generating substantial genetic diversity that facilitates immune evasion. In this context, while monospecific antibody responses against invading pathogens are well characterized, the functional relevance of multispecific or cross-reactive antibodies in limiting viral escape remains poorly understood. Interestingly, the immune system often produces cross-reactive antibodies, with an anticipated role in neutralizing point mutations in HIV surface proteins by cross-reacting with mutants and tolerating them. In light of this paradox, we investigated immune evasion in the context of observed antibody cross-reactivity by screening single-chain variable fragment (scFv) antibodies against several crucial HIV-1 gp41 epitopes using a phage display library. Selected cross-reactive scFvs were biochemically characterized for binding affinity and their ability to recognize envelope protein and its mutants expressed on the cell surface. High-affinity cross-reactive scFvs showed physiologically relevant affinities for peptide epitopes, their analogs, and the native HIV-1 gp41 protein. We determined the crystal structure of a high-affinity, cross-reactive scFv DE94, and gained insights into the molecular interactions of scFv antibodies with peptide epitopes and their natural mutants using molecular docking studies. This analysis provides mechanistic insight into antibody multispecificity and could contribute to the development of therapeutics against immune-evading pathogens and pave the way for innovative strategies to combat viral infections, including emerging global threats.

African trypanosomiasis is a neglected tropical disease transmitted by tsetse flies ( Glossin a spp.) in sub-Saharan Africa. The fly’s saliva carries parasitic unicellular trypanosomes, such as Trypanosoma brucei , leading to infections in humans, domestic animals, and wildlife. Tsetse flies feed on a broad spectrum of hosts, including humans, elephants, buffaloes, rhinos, hippos, turtles and monitor lizards. To understand how the insects can penetrate such diverse skin types, we detailed the anatomical structures involved in tsetse blood feeding, their mechanical properties and the forces exerted by the fly during probing. We found that the tsetse fly’s feeding apparatus does not rely on exceptionally unique structures or extraordinary forces. Instead, the tsetse fly has evolved subtle yet highly efficient adaptations, which include a labellum equipped with arrays of small teeth. When combined with a robust retraction movement of the proboscis, these structures create lesions on various types of skin, thus facilitating blood pool feeding on a broad host spectrum.