The Library of Brain Glycans (LBG) User Guide

The Library of Brain Glycans (LBG) is a freely accessible database designed to assist researchers in exploring the composition, structure, and biological context of brain glycans. It integrates mass spectrometry and liquid chromatography data, allowing searches by species, brain region, developmental stage, and more. The LBG is an initiative of the Human Glycome Project whose mission is to catalogue and define the structures and functions of all human glycoconjugates.

Accessing the Database

To begin, navigate to the LBG database:

Searching the Library

The LBG search tool is designed to help you quickly find glycan entries using flexible and intuitive input. Whether you're looking for a specific glycan by ID, composition, species, organ, its specific structure or study, the search bar can handle exact matches as well as partial or fuzzy queries. You can also explore the full dataset with a single wildcard. Below is a guide on how to use the search effectively:

How to use the search functionality?

  1. Search Input: Use the search bar to look up glycan entries. You can search using any of the following parameters:

    • LBG ID: A unique identifier assigned to each glycan (e.g., LBG-1L3V8).
    • GlyTouCan ID: Standardized glycan identifier from the GlyTouCan database (e.g., G59161CI).
    • Glycan Composition: Search by monosaccharide composition using one-letter codes followed by a number of each component (e.g., H5N3). The codes represent:
      • H – Hexose (e.g., Glucose, Galactose, Mannose)
      • N – N-acetylhexosamine (e.g., GlcNAc, GalNAc)
      • F – Fucose
      • P – Phosphate
      • T – Sulphate
      • A – Glucuronic acid (GlcA)
      • G – N-glycolylneuraminic acid (Neu5Gc)
      • S – N-acetylneuraminic acid (Neu5Ac)
      • E – Neu5Ac ethyl esterified (EE)
      • M – Neu5Ac methyl amidated (MA)
    • Species: The English name of the species (e.g., mouse, human).
    • Organ: The organ in which the glycan was detected (e.g., brain).
    • Organ Structure: Currently limited to cortex.
    • Stage of life: Filter by stage of life of the observed species (e.g. adult).
    • Study: Searching by words of the title or full study name(e.g. Unpublished).
    • All Entries: To view the complete dataset, leave the search bar empty or enter a star (*).

  2. Executing the Search: Press Enter or click the search icon to run the query.

  3. Fuzzy Searching:
    The search supports fuzzy matching, which allows it to find close or partial matches even if the input isn't exact.
    For example:

    • Typing humna will still return results for human.
    • Searching for H5 may return results like H5N3.

    This helps ensure that small typos or incomplete inputs don’t block useful results. If you receive more entries than expected, it's likely due to fuzzy matching—this is intended to help you discover potentially relevant data even with imperfect queries.

How to use filtering functionality?

The LBG database provides extensive filtering capabilities to refine searches based on specific research needs. Users can currently filter glycans based on:

  • Species: Select specific organisms such as Human, Mouse, or Rat. Standard glycans used for reference are also available.
  • Tissues: Choose between glycans derived from Brain tissue or Standard references.
  • Structures will let users refine results further to structures such as the Cortex or Standard, based on current database contents.
  • Stages of Life: Narrow down results to developmental stages including Fetal, Neonate – 24h, Neonate – 48h, Adult, or Standard.
  • Study: Narrow down results to certain studies.
  • Brain Specific: Filter glycans that are specific to the brain (Yes) or more broadly distributed (No).
  • Mass: Define a minimum and maximum molecular weight range to locate glycans of similar size.
  • GU (Glucose Unit): Filter by chromatographic retention using GU values.

Filters with checkboxes are applied immediately when clicked. For Mass and GU filters, values must be entered manually and applied by clicking the Apply button.

Data Table

The search results are displayed in a structured tabular format, providing detailed glycan-related data. Each row corresponds to a glycan entry, and the table includes a customizable set of columns.

Users can manage which columns are visible in the table using a drag-and-drop interface. Each column has a checkbox to toggle its visibility, and users can also reorder columns to suit their preferences.

Default Visible Columns (checked by default):

  • Image: A structural image of the glycan using SNFG nomenclature.
  • LBG ID: A unique identifier for each glycan entry, formatted as LBG-***** where the wildcard can be any number or letter.
  • GlyTouCan ID: Identifier linking to the glycan's record in the GlyTouCan database.
  • Mass: Molecular weight of the glycan, measured in Daltons.
  • Composition: Monosaccharide composition of the glycan.
  • GU Min / Mean / Max: Minimum, mean, and maximum glucose unit (GU) values.
  • Sialic Derivatization: Indicates if the glycan was derivatised during analysis.
  • Species: The species in which the glycan was found.
  • Organ: The organ or tissue in which the glycan was detected.
  • Structures: Specific structural features or motifs of the glycan.

Additional Available Columns (can be enabled by the user):

  • Studies group age
  • Stages of Life
  • Reference IDs
  • Studies
  • Journals
  • Years
  • Last Authors
  • DOI

Clicking on a glycan entry reveals further details, such as references, sublocation (e.g., brain region or cell type), and experimental methods used to identify the glycan.

Library Design and Structure

The Library of Brain Glycans (LBG) is a curated and continuously updated resource focused on glycan structures identified in the brain and related neural systems.The database is structured to integrate multiple layers of information, including species, developmental stages, brain regions, and analytical data thus allowing researchers to navigate complex glycobiological relationships efficiently.

Data description

To ensure consistency, comparability, and high data quality, the current scope of the library is limited to glycans that meet the following criteria: - N-glycans - Derivatisation with procainamide (ProA)
- Assignment of normal-phase glucose unit (GU) values
based on relative elution positions determined by HILIC-UPLC (hydrophilic interaction liquid chromatography – ultra-performance liquid chromatography)

These criteria were chosen for several reasons:

  1. Data comparability: GU assignment via HILIC-UPLC enables consistent retention alignment across different studies, making cross-study comparisons feasible.
  2. Broad compatibility: This analytical setup is widely used in glycobiology laboratories, making it likely that many future studies will be eligible for inclusion.
  3. Enhanced sensitivity: ProA was selected over alternatives like 2-aminobenzamide (2-AB) due to its superior fluorescence and ionisation properties.

Studies using compatible analytical methods (ProA derivatisation and HILIC-UPLC) are eligible for inclusion in the LBG. Contributors are encouraged to consult the methods sections of published example studies to determine compatibility.

Please note that the use of alternative derivatisation agents (e.g., 2-AB) or different chromatographic modes can shift the relative elution positions of glycans, which may compromise comparability and disqualify the data.

Importantly, while the LBG is branded as a "brain glycan" resource, its scope includes:

  • All glycans detected in the central nervous system (CNS), whether in vivo or derived from in vitro models (e.g., neural cell lines, brain organoids)
  • All glycan types: N-glycans (initial focus), as well as O-glycans, glycolipids, glycoRNAs, and other glycoconjugates (future versions)

The current release includes only N-linked glycans, but future updates will support expanded glycan classes and additional biological contexts.

The LBG also accommodates both derivatised and unmodified Neu5Ac (sialic acids). In this release, derivatisation distinguishes sialic acid linkages via:

  • Ethyl esterification of α(2–6)-linked Neu5Ac
  • Methyl amidation of α(2–3)-linked Neu5Ac

Other linkage-specific derivatisation strategies may be supported in future updates.

In summary, the LBG is designed to grow with the field, while maintaining strict curation criteria to ensure data integrity and cross-study usability.

Database Structure and Components

The LBG follows a relational database model, interconnecting chemical glycan data (such as molecular mass, monosaccharide composition, and chromatographic retention) with biological metadata describing in situ expression patterns (such as species, brain regions, and life stages). Each glycan is represented with a rich, structured profile that integrates experimental, biological, and bibliographic information, forming the core of the database.

Glycan Overview

  • LBG ID: Internal unique identifier (e.g., LBG-X4NJX)
  • GlyTouCan ID: External ID linking to the GlyTouCan database
  • Structure Image: Visual representation of the glycan based on its monosaccharide composition
  • Composition: Compact code representing the glycan’s building blocks (e.g., H4N2)
  • Mass: Molecular mass (in Da)
  • GU Range: GU Min, Mean, and Max — derived from HILIC-UPLC
  • Sialic Derivatisation: Indicates if linkage-specific derivatisation was used (Yes/No)
  • Brain Specific: Indicates whether this glycan is uniquely observed in the brain (Yes/No)

Expression Profile

Entries contain detailed contextual metadata showing in which conditions the glycan was observed:

  • Species: Scientific name, linked to NCBI Taxonomy ID
  • Age / Life Stage: Developmental stage (e.g., Adult, Neonate-24h, Neonate-48h)
  • Tissue: Always "Brain" for now, with UBERON ontology term (e.g., UBERON_0000956 for Cortex)
  • Region: Brain structure (currently limited to Cortex, with UBERON support)

This structured tagging enables powerful filtering and exploration of spatial and temporal glycan expression patterns.

Study of Origin

Each glycan entry is linked to the study (or studies) from which it was derived, including:

  • Study Title
  • Journal and Publication Year
  • DOI or Link to the publication
  • Last Author (with future support for full author lists)

If a glycan comes from an unpublished or internal dataset, this is clearly noted as “Unpublished study.”research.

Curation and Versioning

Curation Process

The LBG follows a rigorous curation model to ensure data accuracy, consistency, and scientific value:

  • Expert Manual Curation: All entries are initially curated manually by domain experts to ensure high-quality annotation and consistency across the database.
  • User Contributions: To support the growth of the LBG, researchers can already submit their data for expert review. While a structured submission form is currently in development, contributions are welcome via:
    • Direct submission of glycans described in published papers
    • Contacting curators with datasets or study details for consideration
    • Suggesting corrections or updates to existing entries

Regardless of the submission pathway, all external data will undergo rigorous validation before inclusion. This includes: - Manual inspection by expert curators - Consistency checks with existing database entries - Structural and analytical data verification

📬 To initiate the curation process, researchers should contact the LBG curators at
lbg@genos.hr or via the contact form found in the website footer.
Your contribution will be reviewed and, if accepted, added to a future version of the library.

Toward Semi-Automated Curation (Planned)

If the volume of data grows substantially, a semi-automated curation pipeline may be introduced to streamline validation while preserving expert oversight.

Versioning

The LBG is committed to transparency and reproducibility through a robust versioning policy. While versioning is not yet implemented in this initial release, it will be central to future development.

Versioning Plan

  • Stable Glycan IDs: Each glycan receives a unique, stable identifier within a version.
  • Backwards Accessibility: Older versions of the dataset will remain accessible, enabling researchers to reference specific data snapshots and ensure reproducibility.
  • Deprecation Policy: In cases where structures are merged or reassigned, previous identifiers may be retired but will remain viewable in archived versions.

Version Numbering System

LBG will use a three-digit semantic versioning system:

  • Major (X.0.0) – Large-scale dataset additions or conceptual shifts (e.g., integration of diagnostic fragments, pathology links, or entire new organism groups).
  • Minor (0.X.0) – Moderate updates, such as new studies added, ontology upgrades, or major feature enhancements.
  • Patch (0.0.X) – Small updates or fixes, such as minor corrections, UI tweaks, or backend optimizations.

This system will provide clear version tracking and allow researchers to cite precise versions in their work, supporting scientific rigor and transparency.

The LBG’s versioning and curation frameworks are designed to balance scientific innovation with data integrity, ensuring the database evolves responsibly with the field of brain glycobiology.

Additional Resources

  • About: Learn more about the LBG project and its objectives by visiting the "About" section.
  • Terms and conditions: Familiarize yourself with the terms governing the use of the database.
  • Privacy policy: Understand how your data is handled by reviewing the privacy policy.
  • Contact form: Understand how your data is handled by reviewing the privacy policy.

For further assistance or inquiries, please refer to the contact information provided on the LBG website.

How to Cite, Submit and Contact?

How to Cite LBG Database?

To cite the Library of Brain Glycans, please refer to the related publication.

Related Publication:

How to submit your data?

We are currently developing a dedicated data submission form to streamline contributions. In the meantime, researchers can submit their studies or datasets using the submission form on our contact page or by contacting us directly at lbg@genos.hr.

Simply share the research you would like to include, and our curators will review and process it through our internal curation pipeline.

Contact Information

Genos Glycoscience
Biocentar,
Zagreb 10000, Croatia
Email: lbg@genos.hr

Note: This guide is based on the information available as of July 20, 2025.

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