what is basal body in cell

Basal body. Centrioles, from which basal bodies are derived, act as anchoring sites for proteins that in turn anchor microtubules, and are known as the microtubule organizing center (MTOC). These microtubules provide structure and facilitate movement of vesicles and organelles within many eukaryotic cells.

Full Answer

What is the difference between basal cell and squamous cell?

• The shapes of basal cells vary from cubic to columnar while that of squamous cells is flat-shape. • Basal cells usually form the first single layer of cells, which lies on the basement membrane, whereas squamous cell are usually found on the basal cells.

Which is worse basal cell or squamous cell?

Which is worse basal cell or squamous cell cancer? Though not as common as basal cell (about one million new cases a year), squamous cell is more serious because it is likely to spread (metastasize). Treated early, the cure rate is over 90%, but metastases occur in 1%–5% of cases. Click to see full answer.

What happens if basal cell carcinoma is left untreated?

While rare, untreated basal cell carcinoma can spread to other parts of the body, affecting surrounding tissues. The cancerous area can become quite large and in some cases cause disfigurement, especially when on the face. Small bumps can grow into massive protrusions that destroy healthy tissues and create permanent damage.

What is the meaning of a Basil cell?

The basal cell is an epithelial stem cell but can also refer to any cell that sits on an epithelial basement membrane. Epithelia are tissues that line the inner and outer surfaces of the body. Epithelia are tissues that line the inner and outer surfaces of the body.

Where is the basal body found in the cell?

Basal bodies are microtubule-organizing centres that are closely related to centrioles, and are believed to be derived from them. They are located at the bases of cilia and flagella, which they anchor to the cell surface.

What is a basal body made of?

Basal bodies, in the apical cytoplasm at the cilium base, are hollow cylinders made of nine triplets ofmicrotubules, with no central microtubule pair. Cilia are surrounded by aplasma membrane and consist of anaxoneme with a “9 + 2” microtubule arrangement.

What is basal body of flagella?

The basal body of a bacterial flagellum is a rod and a system of rings embedded in the cell envelope.

What is the difference between centrioles and basal bodies?

Centrioles function at the centrosomes to organize cellular microtubules, whereas basal bodies organize the microtubules of cilia. Centrosomes are comprised of a pair of centrioles surrounded by the pericentriolar material (PCM), which possesses microtubule-nucleating activity (Fig.

What are the differences between flagella and basal bodies?

Bacterial flagella are composed of approximately 30 kinds of proteins, and they form a supercomplex [7] . The basal body of the flagellar motor consists of a rotor and a stator. ... The bacterial flagellar motor is a sophisticated nanomachine embedded in the cell envelope.

What are basal bodies in microtubules?

Basal bodies are microtubule-based organelles that assemble cilia and flagella, which are critical for motility and sensory functions in all major eukaryotic lineages.

What do centrioles and basal bodies do?

Centrioles promote formation of spindle poles in mitosis and act as basal bodies to assemble primary cilia in interphase.

What is the structure and function of basal body?

The basal body serves as a nucleation site for the growth of the axoneme microtubules. Centrioles, from which basal bodies are derived, act as anchoring sites for proteins that in turn anchor microtubules, and are known as the microtubule organizing center (MTOC).

What structure forms basal body of cilia?

centriolesThe centrioles form the basal body of cilia or flagella.

Is a basal body a MTOC?

In animals, the two most important types of MTOCs are 1) the basal bodies associated with cilia and flagella and 2) the centrosome associated with spindle formation.

What is the arrangement of basal body?

The mature basal body is composed of two sections; a 9 + 0 triplet arrangement of microtubules (A-, B- and C-tubules) at the proximal end of the basal body (Figs. 1b1, ​2) and a transition zone, composed of a 9 + 0 arrangement of doublet microtubules.

What is a Basal Cell?

To understand what a basal cell is, it is first best to gain an understanding of the tissue where it is found – the epithelium.

What are basal cells called?

Basal cells are more likely to be called epithelial stem cells in scientific texts to distinguish them from the location-derived name. As yet, the full mechanisms of cell renewal in the epithelia are unknown. Other terms used to describe basal stem cells are keratinocytes (of the skin) and basal epithelial cells.

What are the different types of basal cell carcinoma?

The main basal cell cancer types are: 1 Nodular or solid basal cell carcinoma: the most common type that produces colorless or pale bump-like lesions that can become ulcer-like. 2 Micronodular basal cell carcinoma: multiple small lesions (flat or bumps) with a greater risk of recurrence due to the diffused pattern; most commonly found on the back. 3 Superficial basal cell carcinoma: small budding growths in the epidermis of the skin, most commonly on the trunk and shoulders. 4 Sclerosing or morpheaform basal cell carcinoma: deposits of collagen and fibroblasts make this rare type look a little like a white or yellow scar; one of the more aggressive forms. 5 Infiltrative basal cell carcinoma: thin, white clusters of abnormal cells found primarily on the face and upper body; rare but aggressive. 6 Fibroepithelial basal cell carcinoma: a soft bump most commonly found on the lower back. 7 Pigment basal cell carcinoma: as the name suggests, these are brown or black nodular, micronodular, or superficial BCCs that contain melanin-producing cells as well as basal cells. Most BCCs are amelanotic – they do not involve melanocytes that are associated with melanoma. 8 Cystic basal cell carcinoma: a rare form with grayish bumps filled with fluid. 9 Rodent ulcer: untreated BCCs eventually form ulcers in the middle of the tumor that leave a hole in the skin.

What are the characteristics of basal cells?

One characteristic of the basal cell is the presence of hemidesmosomes – protein complexes that allow them to adhere to the underlying basement membrane. In people with genetic abnormalities that prevent the formation of hemidesmosomes, the skin and mucous membranes are very fragile.

How long does it take to die from metastatic basal cell carcinoma?

Metastatic basal cell carcinoma prognosis is poor with death occurring within four and a half years for most patients. However, it is extremely rare to find cases of advanced BCC. Today, targeted therapies can increase overall survival rates even for locally advanced and metastatic BCCs.

How many types of cells can be produced in basal cells?

A basal stem cell can produce 2 cell types. Symmetrical division – the production of two identical daughter cells – is also possible in basal stem cells.

What is the function of basal cells?

Basal cell function is two-fold: cell renewal and cell adhesion. New research has also not yet uncovered the deeper mysteries of asymmetric stem cell division where, instead of two identical daughter cells being formed, one functional cell and one stem cell are produced.

What is the basal body?

The basal body is the structure that represents the flagellar motor. Though this suggests that the structure and the motor are one and the same, this cannot be stated with confidence, since some structural components necessary for the full function of the motor are missing from the current model of the basal body. Consequently, each time a new component has been found, the definition of the basal body has been refined. The correspondence between the structure and function of the basal body is summarized in Table 7.3. The two types of terminology used in the table often lead to confusion because they are often used without definition. In what follows, the structural terminology will be used as far as possible.

How many basal bodies are there in a cell?

The ciliate Tetrahymena thermophila has more than 700 basal bodies per cell, making it an excellent choice for the study of the structure, function, and assembly of basal bodies. Here, we describe methods for cryofixation of Tetrahymena by high-pressure freezing and freeze-substitution (HPF/FS) for the analysis of basal body structure with advanced electron microscopy techniques. Electron tomography of semi-thick HPF/FS sections was used to generate high-resolution three-dimensional images and models that reveal the intricate structure of basal bodies and associated structures. Immuno-labeling of thin sections from the same HPF/FS samples was used to localize proteins to specific domains within the basal body. To further optimize this model system, we used cell cycle synchronization to increase the abundance of assembling basal bodies. The Tetrahymena genome has been sequenced and techniques for genetic manipulations, such as construction of gene deletion strains, inducible expression and epitope tagging of proteins are now available. These advances have helped to make Tetrahymena a tractable experimental model system. Collectively, these methods facilitate studies of the mechanism of basal body assembly, the functions of basal body constituents and the cytological role of the basal body as a whole.

How do basal bodies attach to the cell membrane?

To assemble flagella, basal bodies first attach to the plasma membrane by transition fibers associated with the triplet microtubules ( Ringo, 1967; Weiss et al., 1977; Gaffal, 1988; Silflow et al., 2001; O'Toole et al., 2003 ). We have little detailed understanding of the mechanisms by which basal bodies dock to the plasma membrane in Chlamydomonas, but clues may come from studies in mammalian cells. In these cells, basal bodies often are centrioles that move to the cell surface and attach to the membrane. A membrane vesicle first attaches to the distal end of the centriole and forms a cap over the end of the centriole, and the complex then migrates to the cortex, where it initiates the formation of a primary cilium ( Sorokin, 1968 ). A number of centrosomal proteins that help anchor centrioles to the centrosomal matrix have been identified (reviewed by Bornens, 2002 ). A centriole-associated protein, Odf2, or cenexin, forms a discrete appendage on centrioles that appears to be essential for the formation of primary cilia. In odf2−/− mouse cells, ciliogenesis, but not cell division, is completely suppressed ( Ishikawa et al., 2005 ), which indicates that Odf2 may be an important docking protein.

Where are basal bodies and transition regions located?

Basal bodies and transition regions are linked to the plasma membrane by three different structures, each of whose attachment to the membrane is associated with intramembrane particles seen in freeze-fractured cells ( Weiss et al., 1977 and see Chapter 11 ). Transition fibers, or basal body struts ( Ringo, 1967; O'Toole et al., 2003 ), radiate from the distal end of the basal body and anchor to particles in the plasma membrane ( Weiss et al., 1977 ). The base of the transition region, where the distal end of the basal body attaches to the membrane, is attached to a ring of particles called the “flagellar bracelet” ( Weiss et al., 1977 ). As seen in freeze-fractured preparations (see Figure 11.3 ), the bracelet appears to be an important structure in Chlamydomonas and is composed of uniformly sized particles that touch one another ( Weiss et al., 1977 ). Distal to the basal body, near the mid-transition region, flagellar microtubules are associated with particles that form the flagellar “necklace.” These have been proposed to be attached to prominent bridges, or “connectives,” that form pairs of links ( Figure 10.1A, G) that appear as Y-shaped “champagne glass” structures in cross-section ( Ringo, 1967; Gilula and Satir, 1972; Besharse and Horst, 1990) and hence are often referred to as “Y-shaped” connectors or links. These appear to tether the membrane to the doublet microtubules in the transition region. However, the number of necklace rows should match the number of connectives seen in thin-sectioned flagella; that is, there should be two rows of particles, but, in Chlamydomonas, Weiss et al. (1977) reported three rows of necklace particles, which would be more consistent with particles being excluded from the attachment sites of the connectives. Ciliary necklaces are commonly found in other cilia, including cilia of Paramecium ( Watanabe, 1990 ), Tetrahymena ( Sattler and Staehelin, 1974 ), and avian reproductive tracts ( Chailley et al., 1990 ).

Where do microtubules attach to the plasma membrane?

Once basal bodies attach to the plasma membrane and to the cytoskeleton ( Wright et al., 1983; Hoops et al., 1984; Silflow et al., 2001; O'Toole et al., 2003 ), flagellar doublet microtubules assemble onto the ends of the A- and B-tubules of each triplet, and a transition region, which has prominent links to the newly forming flagellar membrane and contains an inner H-shaped cup region, distal to which the central microtubules grow, is formed ( Figure 10.1C–G ). The polarity of the central microtubules is the same as that of the doublet microtubules (the plus-end is at the distal flagellar tip) ( Euteneur and McIntosh, 1981a,b) and it is generally accepted that central microtubules, like the doublets, assemble at the distal tip ( Johnson and Rosenbaum, 1992). However central microtubules have been found to grow proximally, into the basal body, in living Chlamydomonas transition region mutants ( Jarvik and Suhan, 1991) and in isolated respiratory cilia ( Dentler and LeCluyse, 1982a ). The site at which central microtubules assemble, therefore, is not completely understood.

What is the role of basal bodies in replication?

The basal body is essential for ciliary and centriolar growth and replication, probably serving as a template. Cilia appear and grow only at sites first occupied by basal bodies. How this occurs is not known, but these structures characteristically develop at right angles to the existing basal body during replication (see preceding for discussion on DNA). Basal bodies serve to nucleate axonemes during reconstitution in vitro; their exclusion results in growth of only singlet microtubules. However, centrioles can appear de novo during spermiogenesis in several plant species.

How are basal bodies formed?

Basal bodies are formed either from self-duplicating centrioles or fromblepharoplasts, which are essentially centrioles that form in the cell de novo (Sharp, 1914;

What is the basal body?

The basal body is the structure that represents the flagellar motor. Though this suggests that the structure and the motor are one and the same, this cannot be stated with confidence, since some structural components necessary for the full function of the motor are missing from the current model of the basal body.

What is the basal body of the cell cycle?

Cilia and the Cell Cycle. The basal body (see section “Centrosomes and Basal Bodies”) is generated from the centrioles that are also components of mitotic machinery. Therefore, cell division, cell differentiation, and ciliogenesis are inherently linked.

How do basal bodies attach to the cell membrane?

To assemble flagella, basal bodies first attach to the plasma membrane by transition fibers associated with the triplet microtubules ( Ringo, 1967; Weiss et al., 1977; Gaffal, 1988; Silflow et al., 2001; O'Toole et al., 2003 ). We have little detailed understanding of the mechanisms by which basal bodies dock to the plasma membrane in Chlamydomonas, but clues may come from studies in mammalian cells. In these cells, basal bodies often are centrioles that move to the cell surface and attach to the membrane. A membrane vesicle first attaches to the distal end of the centriole and forms a cap over the end of the centriole, and the complex then migrates to the cortex, where it initiates the formation of a primary cilium ( Sorokin, 1968 ). A number of centrosomal proteins that help anchor centrioles to the centrosomal matrix have been identified (reviewed by Bornens, 2002 ). A centriole-associated protein, Odf2, or cenexin, forms a discrete appendage on centrioles that appears to be essential for the formation of primary cilia. In odf2−/− mouse cells, ciliogenesis, but not cell division, is completely suppressed ( Ishikawa et al., 2005 ), which indicates that Odf2 may be an important docking protein.

Where are basal bodies and transition regions located?

Basal bodies and transition regions are linked to the plasma membrane by three different structures, each of whose attachment to the membrane is associated with intramembrane particles seen in freeze-fractured cells ( Weiss et al., 1977 and see Chapter 11 ). Transition fibers, or basal body struts ( Ringo, 1967; O'Toole et al., 2003 ), radiate from the distal end of the basal body and anchor to particles in the plasma membrane ( Weiss et al., 1977 ). The base of the transition region, where the distal end of the basal body attaches to the membrane, is attached to a ring of particles called the “flagellar bracelet” ( Weiss et al., 1977 ). As seen in freeze-fractured preparations (see Figure 11.3 ), the bracelet appears to be an important structure in Chlamydomonas and is composed of uniformly sized particles that touch one another ( Weiss et al., 1977 ). Distal to the basal body, near the mid-transition region, flagellar microtubules are associated with particles that form the flagellar “necklace.” These have been proposed to be attached to prominent bridges, or “connectives,” that form pairs of links ( Figure 10.1A, G) that appear as Y-shaped “champagne glass” structures in cross-section ( Ringo, 1967; Gilula and Satir, 1972; Besharse and Horst, 1990) and hence are often referred to as “Y-shaped” connectors or links. These appear to tether the membrane to the doublet microtubules in the transition region. However, the number of necklace rows should match the number of connectives seen in thin-sectioned flagella; that is, there should be two rows of particles, but, in Chlamydomonas, Weiss et al. (1977) reported three rows of necklace particles, which would be more consistent with particles being excluded from the attachment sites of the connectives. Ciliary necklaces are commonly found in other cilia, including cilia of Paramecium ( Watanabe, 1990 ), Tetrahymena ( Sattler and Staehelin, 1974 ), and avian reproductive tracts ( Chailley et al., 1990 ).

Where do microtubules attach to the plasma membrane?

Once basal bodies attach to the plasma membrane and to the cytoskeleton ( Wright et al., 1983; Hoops et al., 1984; Silflow et al., 2001; O'Toole et al., 2003 ), flagellar doublet microtubules assemble onto the ends of the A- and B-tubules of each triplet, and a transition region, which has prominent links to the newly forming flagellar membrane and contains an inner H-shaped cup region, distal to which the central microtubules grow, is formed ( Figure 10.1C–G ). The polarity of the central microtubules is the same as that of the doublet microtubules (the plus-end is at the distal flagellar tip) ( Euteneur and McIntosh, 1981a,b) and it is generally accepted that central microtubules, like the doublets, assemble at the distal tip ( Johnson and Rosenbaum, 1992). However central microtubules have been found to grow proximally, into the basal body, in living Chlamydomonas transition region mutants ( Jarvik and Suhan, 1991) and in isolated respiratory cilia ( Dentler and LeCluyse, 1982a ). The site at which central microtubules assemble, therefore, is not completely understood.

How many basal bodies are there in a cell?

The ciliate Tetrahymena thermophila has more than 700 basal bodies per cell, making it an excellent choice for the study of the structure, function, and assembly of basal bodies. Here, we describe methods for cryofixation of Tetrahymena by high-pressure freezing and freeze-substitution (HPF/FS) for the analysis of basal body structure with advanced electron microscopy techniques. Electron tomography of semi-thick HPF/FS sections was used to generate high-resolution three-dimensional images and models that reveal the intricate structure of basal bodies and associated structures. Immuno-labeling of thin sections from the same HPF/FS samples was used to localize proteins to specific domains within the basal body. To further optimize this model system, we used cell cycle synchronization to increase the abundance of assembling basal bodies. The Tetrahymena genome has been sequenced and techniques for genetic manipulations, such as construction of gene deletion strains, inducible expression and epitope tagging of proteins are now available. These advances have helped to make Tetrahymena a tractable experimental model system. Collectively, these methods facilitate studies of the mechanism of basal body assembly, the functions of basal body constituents and the cytological role of the basal body as a whole.

How many rings are there in the basal body?

The basal body contains rings and a rod penetrating through them. The number of rings varies depending on the membrane systems: four rings in most of Gram-negatives and two rings in Gram-positives exemplified by B. subtilis. Some variations in the number (such as five rings in C. crescentus) have been occasionally seen. The fifth ring might be a ghost image of electron microscopy or could be erroneously added during ring formation (see ‘Rod’).

What is basal cell carcinoma?

Overview. Basal cell carcinoma is a type of skin cancer that most often develops on areas of skin exposed to the sun. This photograph shows a basal cell carcinoma that affects the skin on the lower eyelid. Basal cell carcinoma is a type of skin cancer.

Where does basal cell carcinoma develop?

Basal cell carcinoma usually develops on sun-exposed parts of your body, especially your head and neck. Less often, basal cell carcinoma can develop on parts of your body usually protected from the sun, such as the genitals.

What is the name of the cancer that is most often found on the face?

Basal cell carcinoma is a type of skin cancer that most often develops on areas of skin exposed to the sun, such as the face. On brown and Black skin, basal cell carcinoma often looks like a bump that's brown or glossy black and has a rolled border.

What is the name of the cancer that occurs when a cell moves upward?

As new cells move upward, they become flattened squamous cells, where a skin cancer called squamous cell carcinoma can occur. Melanoma, another type of skin cancer, arises in the pigment cells (melanocytes). Basal cell carcinoma occurs when one of the skin's basal cells develops a mutation in its DNA.

What are the factors that increase the risk of basal cell carcinoma?

Factors that increase your risk of basal cell carcinoma include: Chronic sun exposure. A lot of time spent in the sun — or in commercial tanning beds — increases the risk of basal cell carcinoma. The threat is greater if you live in a sunny or high-altitude location, both of which expose you to more UV radiation.

When does basal cell carcinoma become more common?

But it can also affect younger adults and is becoming more common in people in their 20s and 30s. A personal or family history of skin cancer.

What is the most common type of basal cell carcinoma?

The most common type of basal cell carcinoma, this lesion often appears on the face and ears. The lesion may rupture, bleed and scab over. A brown, black or blue lesion — or a lesion with dark spots — with a slightly raised, translucent border.

What is basal cell carcinoma?

Basal cell carcinoma (BCC) is a type of skin cancer that begins in the basal cells. Normal basal cells line the epidermis. They’re the skin cells that replace old cells with new ones. Cancer of the basal cells results in tumors that appear on the skin’s surface. These tumors often look like sores, growths, bumps, scars, or red patches.

Where do basal cell carcinomas develop?

What are the symptoms of basal cell carcinoma? Almost all BCCs develop on parts of the body frequently exposed to the sun. Tumors can develop on the face, ears, shoulders, neck, scalp, and arms. In very rare cases, tumors develop on areas not often exposed to sunlight. BCCs are typically painless.

How to diagnose BCC?

The first step in diagnosing BCC will be a visual inspection from a dermatologist. They’ll check your skin head-to-toe to look for any skin growths or discolorations. They’ll also ask about your medical history, including family history of skin cancers.

What is a BCC on the back?

Superficial BCC: This type takes on the appearance of a reddish patch on the skin, which is often flat and scaly. It continues to grow and often has a raised edge. It typically takes on this appearance when on the back or chest.

What causes skin cancer?

Skin cancers, including BCC, are primarily caused by long-term sun or ultraviolet (UV) light exposure. These cancers can also be caused by intense occasional exposure often resulting in sunburn. In rarer cases, other factors can cause BCC. These include: exposure to radiation. exposure to arsenic.

What is a non-ulcerative BCC?

Nonulcerative BCC: This type appears as a bump on the skin that is white, skin-colored, or pink. It’s often translucent, with blood vessels underneath that are visible. This is the most common type of BCC. It most commonly appears on the neck, ears, and face. It can rupture, bleed, and scab over.

Can BCC spread to other parts of the body?

While BCC almost never spreads to other places in the body (metastasizes), it can still result in disfigurement. In rare cases, it can spread to other parts of the body. If it does, it can become life-threatening. BCC is the most common type of skin cancer.

What does BCC look like?

BCCs can look like open sores, red patches, pink growths, shi ny bumps, scars or growths with slightly elevated, rolled edges and/or a central indentation. At times, BCCs may ooze, crust, itch or bleed. The lesions commonly arise in sun-exposed areas of the body. In patients with darker skin, about half of BCCs are pigmented (meaning brown in color).

What is the name of the cell that sheds as new ones form?

One of three main types of cells in the top layer of the skin, basal cells shed as new ones form. BCC most often occurs when DNA damage from exposure to ultraviolet (UV) radiation from the sun or indoor tanning triggers changes in basal cells in the outermost layer of skin (epidermis), resulting in uncontrolled growth.

Why are BCCs curable?

Because BCCs grow slowly, most are curable and cause minimal damage when caught and treated early. Understanding BCC causes, risk factors and warning signs can help you detect them early, when they are easiest to treat and cure.

How common is BCC?

How widespread is BCC? Basal cell carcinoma is quite common, and the number of reported cases in the U.S. has steadily increased. An estimated 3.6 million Americans are diagnosed with BCC each year. More than one out of every three new cancers are skin cancers, and the vast majority are BCCs.

Do all BCCs have the same appearance?

Please note: Since not all BCCs have the same appearance, these photos serve as a general reference to what they can look like. If you see something new, changing or unusual on your skin, schedule an appointment with your dermatologist.

Can BCCs spread beyond the tumor site?

While BCCs rarely spread beyond the original tumor site, if allowed to grow, these lesions can be disfiguring and dangerous. Untreated BCCs can become locally invasive, grow wide and deep into the skin and destroy skin, tissue and bone.

Overview

Symptoms

Causes

• Basal cell carcinoma occurs when one of the skin's basal cells develops a mutation in its DNA. Basal cells are found at the bottom of the epidermis — the outermost layer of skin. Basal cells produce new skin cells. As new skin cells are produced, they push older cells toward the skin's surface, where the old cells die and are sloughed off. The proc...

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Risk Factors

Complications

Prevention