Cell junctions connect cells to each other and to the extracellular matrix through four main types: anchoring junctions, occluding junctions, channel-forming junctions, and signal-relaying junctions. Anchoring junctions include cadherins and integrins, which link cells together and attach cells to the extracellular matrix. Tight junctions and desmosomes form barriers and anchor cells via intermediate filaments. Gap junctions connect cell cytoplasm to allow communication through molecule and ion transfer. The extracellular matrix surrounds cells and is composed of collagen fibers and proteoglycans.
A membrane protein is a protein molecule that is attached to, or associated with the membrane of a cell or an organelle.
More than half of all proteins interact with membranes.
A membrane protein is a protein molecule that is attached to, or associated with the membrane of a cell or an organelle.
More than half of all proteins interact with membranes.
This presentation gives an overview of Lipid Rafts, how it was discovered, its importance and the future research in this area,Feel free to comment and ask any questions
Nucleus: Structure and function
nuclear membrane
nuclear lamins
Nuclear pore complexe
nuclear matrix, composition and its role
cajal bodies
SFCs
nuclear speckles
PML bodies
Nucleolus
Chaperones are a functionally related group of proteins that assist the covalent folding or unfolding and the assembly or disassembly of other macromolecular structures.
Basics only
Ribosome’s are a cell structure that makes protein (seat of protein synthesis).
• Ribosomes are often referred as PROTEIN FACTORY of the cell.
• Protein is needed for many cell functions such as repairing damage or directing
chemical processes.
• The ribosome is a complex molecule made of ribosomal RNA molecules and
proteins that form a factory for protein synthesis in cells.
This presentation intends to explore the communication of the cell within and others for sustainability along the regulation mechanisms by the cellular neural networks and others to sing the song of the life.
This presentation gives an overview of Lipid Rafts, how it was discovered, its importance and the future research in this area,Feel free to comment and ask any questions
Nucleus: Structure and function
nuclear membrane
nuclear lamins
Nuclear pore complexe
nuclear matrix, composition and its role
cajal bodies
SFCs
nuclear speckles
PML bodies
Nucleolus
Chaperones are a functionally related group of proteins that assist the covalent folding or unfolding and the assembly or disassembly of other macromolecular structures.
Basics only
Ribosome’s are a cell structure that makes protein (seat of protein synthesis).
• Ribosomes are often referred as PROTEIN FACTORY of the cell.
• Protein is needed for many cell functions such as repairing damage or directing
chemical processes.
• The ribosome is a complex molecule made of ribosomal RNA molecules and
proteins that form a factory for protein synthesis in cells.
This presentation intends to explore the communication of the cell within and others for sustainability along the regulation mechanisms by the cellular neural networks and others to sing the song of the life.
power point presentation on the topic cellular level of organization from unit first of subject human anatomy and physiology I for first year B.PHARM it is useful for the student to study easily and find out the material easily for their study it is also useful for techers
Created by Neriza Jane Tambal from University of Southeastern Philippines taking Bachelor of Science in Secondary Education Major in Biological Science.
This presentation was a hard work of investigation and searching time by veterinary students of ULPGC Gran Canaria university. we learned to much about cytology in the process of recompilation of information. We share this knowledge with the desire that it may be useful and instructive for some one interested in cience or maybe other student arround the world. enjoy it!
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
2. What are cell junctions?
The cell junction is a cell-cell or cell-extracellular matrix contact within a tissue of
a multi-cellular organism, especially abundant in epithelia in order to create
pathways for communication, allowing cells to exchange the signals that co-
ordinate their behavior and regulate their patterns of gene expression.
3. FOUR FUNCTIONAL CLASSES OF CELL JUNCTIONS
1. ANCHORING JUNCTIONS- link cell to cell (via cadherins) or cell to ECM (via trans-
membrane integrins).
2. OCCLUDING JUNCTIONS- Seal the gaps between cells in epithelia to make cell sheet
into a impermeable/ selectively permeable barrier.
3. CHANNEL-FORMING JUNCTIONS- Link the cytoplasm of adjacent cells.
4. SIGNAL-RELAYING JUNCTIONS- Involve anchorage proteins for cell to cell signal
transduction.
ANCHORING JUNCTIONS OCCLUDING JUNCTIONS CHANNEL-FORMING JUNCTIONS SIGNAL-RELAYING
JUNCTIONS
4.
5. CADHERINS
• Cadherins are named for calcium dependent adhesion. The external domain of
a cadherin molecule - is made up of many repeats of the same protein chain.
Each repeat has a space for binding calcium. Calcium makes the chain rigid,
helping it to connect with a chain from another cell.
• In addition to an extracellular (outside the cell) component, cadherins also have
a piece that penetrates through the membrane and a piece that is inside the cell.
The interior portions of the cadherins form a complex within the cell.
Figure : Cells of early embryo at about 8-celled stage begin to express E-Cadherin
and as a result become strongly adherent to one another.
6. CLASSES OF CADHERINS
• Classical cadherins include E-cadherin, P-cadherin and N-cadherin .They all have a
similar structure, with five extracellular cadherin repeats, a transmembrane domain,
and an intracellular domain. Adhesion by classic cadherins is involved in some
significant cellular signaling pathways, including Wnt, Hedgehog, Ras, and
RhoGTPase signaling.
• Desmosomal cadherins includes Desmoglein and desmocollin.They are important
in forming a type of cellular junction called a desmosome.
• Protocadherins are a large group of cadherin molecules present in a wide range of
species that are thought to be related to an ancestral cadherin. Their extracellular
domains have more than five repeated cadherin motifs, distinguishing them from
classical cadherins. The intracellular domains of the proto-cadherins are also
different from their classical cousins. They are highly variable, with a variety of
functions in the nervous system, including neuronal differentiation and the
formation of synapses.
• Unconventional cadherins are a large group of cadherins that are not otherwise
categorized into the previous three groups. They include VE-cadherin, R-cadherin,
and many others.
7.
8. SELECTIVE CELL-CELL ADHESION
• Cadherins mediate highly selective recognition, enabling cells of similar type to
stick together and stay segregated from other types of cells.
Epidermal cell
Mesodermal cell
Neural-plate cell
9. ADHERENS JUNCTIONS
• Adherens junctions are cell-cell adhesion complexes that are continuously assembled
and disassembled, allowing cells within a tissue to respond to forces, biochemical
signals and structural changes in their microenvironment. The events leading up
to adherens junction formation are still not entirely clear, but they ultimately result in the
recruitment of transmembrane cadherins, catenins (beta-catenins, alpha-catenins)and
cytoskeletal adaptor proteins that form the primary architecture of adherens junctions.
Enable the cells in the tissue to use their actin cytoskeletons in a co-ordinated way
10. DESMOSOMES
• Desmosomes are a type of anchoring junction in animal tissues that connect adjacent cells.
Anchoring junctions are button-like spots found all around cells that bind adjacent cells
together. Desmosomes have intermediate filaments in the cells underneath that help anchor
the junction, while the other type of anchoring junction, an adherens junction, is anchored by
microfilaments
11. TIGHT JUNCTIONS
• Tight junctions are areas where the membranes of two adjacent cells join
together to form a barrier. The cell membranes are connected by strands of
trans-membrane proteins such as claudins and occludins. Tight junctions
bind cells together, prevent molecules from passing in between the cells,
and also help to maintain the polarity of cells. They are only found in
vertebrates, animals with a backbone and skeleton; invertebrates have
septate junctions instead.
12. GAP JUNCTIONS
• Gap junctions are a type of cell junction in which adjacent cells are connected through protein
channels. These channels connect the cytoplasm of each cell and allow molecules, ions, and
electrical signals to pass between them.
• Gap junctions are important during embryonic development, a time when neighboring cells
must communicate with each other in order for them to develop in the right place at the right
time. If gap junctions are blocked, embryos cannot develop normally.
• Gap junctions make cells chemically or electrically coupled. This means that the cells are
linked together and can transfer molecules to each other for use in reactions. Electrical
coupling occurs in the heart, where cells receive the signal to contract the heart muscle at the
same time through gap junctions. It also occurs in neurons, which can be connected to each
other by electrical synapses in addition to the well-known chemical synapses that
neurotransmitters are released from.
• When a cell starts to die from disease or injury, it sends out signals through its gap junctions.
These signals can cause nearby cells to die even if they are not diseased or injured. This is
called the “bystander effect”, since the nearby cells are innocent bystanders that become
victims. However, sometimes groups of adjacent cells need to die during development, so gap
junctions facilitate this process. In addition, cells can also send therapeutic compounds to
each other through gap junctions, and gap junctions are being researched as a method of
therapeutic drug delivery.
13. GAP JUNCTIONS CONTD……
• In vertebrate cells, gap junctions are made up of connexin proteins.
• The cells of invertebrates have gap junctions that are composed of innexin proteins, which are not related
to connexin proteins but perform a similar function.
• Groups of six connexins form a connexon, and two connexons are put together to form a channel that
molecules can pass through.
• Other channels in gap junctions are made up of pannexin proteins. Relatively less is known about
pannexins; they were originally thought only to form channels within a cell, not between cells.
14. INTEGRINS
• Integrins are proteins that function mechanically, by attaching the cell
cytoskeleton to the extracellular matrix (ECM), and biochemically, by sensing
whether adhesion has occurred.
• The integrin family of proteins consists of alpha and beta subtypes, which form
transmembrane hetero-dimers.
• Integrins function as adhesion receptors for extracellular ligands and transduce
biochemical signals into the cell, through downstream effector proteins.
• Remarkably, they function bidirectionally, meaning they can transmit
information both outside-in and inside-out
15. EXTRA-CELLULAR MATRIX
• Most animal cells release materials into the extracellular space, creating a complex meshwork of
proteins and carbohydrates called the extracellular matrix (ECM). A major component of the
extracellular matrix is the protein collagen. Collagen proteins are modified with carbohydrates, and
once they're released from the cell, they assemble into long fibers called collagen fibrils.
• In the extracellular matrix, collagen fibers are interwoven with a class of carbohydrate-
bearing proteo-glycans, which may be attached to a long polysaccharide backbone.