Publications by authors named "Velickovic D"

Studies generating transcriptomics, proteomics, lipidomics, and metabolomics (colloquially referred to as "omics") data allow researchers to find biomarkers or molecular targets or understand complex biological structures and functions by identifying changes in biomolecule abundance and expression between experimental conditions. Omics data are multidimensional, and oftentimes summarization techniques such as principal component analysis (PCA) are used to identify high-level patterns in data. Though useful, these summaries do not allow exploration of detailed patterns in omics data that may have biological relevance.

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Radical esophagectomy remains the only potentially curative option in the treatment of esophageal cancer. However, this procedure is burdened with high morbidity and mortality rates, even in high-volume centers. A tracheo- or bronchoesophageal fistula (TBF) is rare but is one of the most difficult life-threatening complications following an esophagectomy for cancer treatment.

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  • - Linked glycosylation is a key modification of proteins that impacts lung function by helping proteins fold and facilitating communication between cells, making it crucial for understanding respiratory health.
  • - The study utilized advanced techniques like MALDI mass spectrometry imaging and co-detection by indexing to identify specific glycan structures in various lung regions, showing their unique locations around different cell types.
  • - Results indicated that certain glycan types are concentrated around specific cells and areas in the lungs, hinting that these glycan structures may have distinct roles in cellular function and responses, which could inform future lung research.
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  • A globally significant nitrogen-fixing marine cyanobacterium forms extensive surface blooms in nutrient-poor ocean regions, with diverse morphotypes impacting carbon and nitrogen cycles.
  • This study assessed metabolite abundance in three distinct colony morphotypes from the Red Sea and compared them to two cultivable morphotypes using advanced mass spectrometry techniques.
  • The research found significant variations in metabolites, particularly between natural colonies and the lab-cultured strain, revealing insights for future studies on marine metabolomics.
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Background: Elucidating the intricate structural organization and spatial gradients of biomolecular composition within the rhizosphere is critical to understanding important biogeochemical processes, which include the mechanisms of root-microbe interactions for maintaining sustainable plant ecosystem services. While various analytical methods have been developed to assess the spatial heterogeneity within the rhizosphere, a comprehensive view of the fine distribution of metabolites within the root-soil interface has remained a significant challenge. This is primarily due to the difficulty of maintaining the original spatial organization during sample preparation without compromising its molecular content.

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  • Researchers are focusing on improving proteomic techniques to analyze tissue differences in a way that reflects specific cell types, which could enhance our understanding of complex biological systems like human organs.
  • Current methods for spatially resolved proteomics face challenges in sensitivity and sample recovery, limiting their ability to thoroughly analyze protein content.
  • The study combines advanced technologies, including laser capture microdissection and microPOTS, to significantly increase protein detection, demonstrating the capability to analyze over 5000 proteins from tiny tissue samples and making the process more accessible to research labs.
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The occurrence of the pseudoaneurysm of visceral arteries in the field of chronic pancreatitis is a very rare complication that represents a life-threatening condition. The higher frequency of this complication is in the necrotic form of pancreatic inflammation, especially in patients with formed peripancreatic necrotic collections. The degradation of the arterial wall leads to bleeding and transforms these necrotic collections into a pseudoaneurysm.

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Background: Diabetes is expected to directly impact renal glycosylation, yet to date, there has not been a comprehensive evaluation of alterations in N-glycan composition in the glomeruli of patients with diabetic kidney disease (DKD).

Methods: We used untargeted mass spectrometry imaging to identify N-glycan structures in healthy and sclerotic glomeruli in FFPE sections from needle biopsies of five patients with DKD and three healthy kidney samples. Regional proteomics was performed on glomeruli from additional biopsies from the same patients to compare the abundances of enzymes involved in glycosylation.

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Most of Earth's trees rely on critical soil nutrients that ectomycorrhizal fungi (EcMF) liberate and provide, and all of Earth's land plants associate with bacteria that help them survive in nature. Yet, our understanding of how the presence of EcMF modifies soil bacterial communities, soil food webs, and root chemistry requires direct experimental evidence to comprehend the effects that EcMF may generate in the belowground plant microbiome. To this end, we grew plants in soils that were either inoculated with EcMF and native forest bacterial communities or only native bacterial communities.

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  • The study explores how water-deficit stress affects the metabolism of different plant cell types, specifically looking at leaf palisade and vascular cells in poplar trees.
  • Researchers used advanced techniques like MALDI-MSI to observe unique metabolic changes in these cell types during various stages of water stress and recovery.
  • Findings revealed that palisade cells accumulate flavonoids and phenolic metabolites, while vascular cells focus on sugars and fatty acids, emphasizing the importance of cell-type-specific responses in improving plant resilience to environmental stresses.
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Background: The Human Proteome Project has credibly detected nearly 93% of the roughly 20,000 proteins which are predicted by the human genome. However, the proteome is enigmatic, where alterations in amino acid sequences from polymorphisms and alternative splicing, errors in translation, and post-translational modifications result in a proteome depth estimated at several million unique proteoforms. Recently mass spectrometry has been demonstrated in several landmark efforts mapping the human proteoform landscape in bulk analyses.

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  • The leaf-cutter ant ecosystem, specifically focusing on Atta cephalotes, serves as an effective model for understanding plant biomass breakdown, primarily facilitated by a symbiotic fungus called Leucoagaricus gongylophorus.
  • Researchers utilized advanced imaging techniques on thin sections of fungal gardens to study the degradation of lignin, a complex organic polymer, which is crucial in plant structure.
  • By mapping metabolites and proteins together, they discovered distinct microhabitats related to lignin breakdown, highlighting the fungi's important role in decomposing plant materials and revealing insights into the metabolic processes involved.
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Multiplexed molecular profiling of tissue microenvironments, or spatial omics, can provide critical insights into cellular functions and disease pathology. The coupling of laser microdissection with mass spectrometry-based proteomics has enabled deep and unbiased mapping of >1000 proteins. However, the throughput of laser microdissection is often limited due to tedious two-step procedures, sequential laser cutting, and sample collection.

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Aliphatic carboxylic acids, aldehydes, and ketones play diverse roles in microbial adaptation to their microenvironment, from excretion as toxins to adaptive metabolites for membrane fluidity. However, the spatial distribution of these molecules throughout biofilms and how microbes in these environments exchange these molecules remain elusive for many of these bioactive species due to inefficient molecular imaging strategies. Herein, we apply on-tissue chemical derivatization (OTCD) using 4-(2-((4-bromophenethyl)dimethylammonio)ethoxy)benzenaminium dibromide (4-APEBA) on a co-culture of a soil bacterium ( NCIB 3610) and fungus ( sp.

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Fungal species are foundational members of soil ecosystems with vital contributions that support interspecies resource translocation. The minute details of these biogeochemical processes are poorly investigated. Here, we addressed this knowledge gap by probing fungal growth in a novel mineral-doped soil micromodel platform using spatially-resolved imaging methodologies.

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Probing the entirety of any species metabolome is an analytical grand challenge, especially on a cellular scale. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is a common spatial metabolomics assay, but this technique has limited molecular coverage for several reasons. To expand the application space of spatial metabolomics, we developed an on-tissue chemical derivatization (OTCD) workflow using 4-APEBA for the confident identification of several dozen elusive phytocompounds.

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Due to its speed, accuracy, and adaptability to various sample types, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has become a popular method to identify molecular isotope profiles from biological samples. Often MALDI-MS data do not include tandem MS fragmentation data, and thus the identification of compounds in samples requires external databases so that the accurate mass of detected signals can be matched to known molecular compounds. Most relevant MALDI-MS software tools developed to confirm compound identifications are focused on small molecules (.

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Herein, we assess the complementarity and complexity of data that can be detected within mammalian lipidome mass spectrometry imaging (MSI) matrix-assisted laser desorption ionization (MALDI) and nanospray desorption electrospray ionization (nano-DESI). We do so by employing 21 T Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) with absorption mode FT processing in both cases, allowing unmatched mass resolving power per unit time (≥613k at / 760, 1.536 s transients).

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Article Synopsis
  • There is a growing interest in detailed proteomic methods to analyze tissue diversity at the level of individual cell types, which can enhance our understanding of complex biological systems like human organs.
  • Current spatially resolved proteomics techniques struggle with depth and sensitivity in profiling due to poor sample recovery.
  • The study successfully integrates laser capture microdissection with advanced microfluidic processing and peptide fractionation, enabling the identification of over 5,000 unique proteins from tiny pancreatic tissue samples, revealing distinct microenvironments within islets.
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Deciphering the mechanisms of bacterial fatty acid biosynthesis is crucial for both the engineering of bacterial hosts to produce fatty acid-derived molecules and the development of new antibiotics. However, gaps in our understanding of the initiation of fatty acid biosynthesis remain. Here, we demonstrate that the industrially relevant microbe Pseudomonas putida KT2440 contains three distinct pathways to initiate fatty acid biosynthesis.

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Conventional proteomic approaches measure the averaged signal from mixed cell populations or bulk tissues, leading to the dilution of signals arising from subpopulations of cells that might serve as important biomarkers. Recent developments in bottom-up proteomics have enabled spatial mapping of cellular heterogeneity in tissue microenvironments. However, bottom-up proteomics cannot unambiguously define and quantify proteoforms, which are intact (i.

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Despite their diminutive size, islets of Langerhans play a large role in maintaining systemic energy balance in the body. New technologies have enabled us to go from studying the whole pancreas to isolated whole islets, to partial islet sections, and now to islet substructures isolated from within the islet. Using a microfluidic nanodroplet-based proteomics platform coupled with laser capture microdissection and field asymmetric waveform ion mobility spectrometry, we present an in-depth investigation of protein profiles specific to features within the islet.

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Core histones including H2A, H2B, H3, and H4 are key modulators of cellular repair, transcription, and replication within eukaryotic cells, playing vital roles in the pathogenesis of disease and cellular responses to environmental stimuli. Traditional mass spectrometry (MS)-based bottom-up and top-down proteomics allows for the comprehensive identification of proteins and of post-translational modification (PTM) harboring proteoforms. However, these methodologies have difficulties preserving near-cellular spatial distributions because they typically require laser capture microdissection (LCM) and advanced sample preparation techniques.

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Investigation of the spatial distribution of -glycans in tissue specimens has emerged as a powerful tool in clinical research, in part, because altered -glycans are often a hallmark of disease progression. Mass spectrometry imaging of -glycans relies on peptide -glycanase spraying and tissue incubation for efficient release of -glycans from their carrier proteins. Unstandardized and uncontrolled incubation steps often cause significant delocalization of released -glycans, resulting in the inability to link given -glycan composition to a specific microanatomical region in the tissue.

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Introduction: Multi-organ dysfunction caused by thromboembolic complications may complicate the course of SARS-CoV-2 infection. Most patients require anticoagulant therapy which predisposes them to the development of hemorrhagic syndrome. In critically ill COVID-19 patients secondary infections due to opportunistic pathogens are associated with a high mortality rate.

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