Alae (anatomy)
Encyclopedia
The alae is a protruding ridge that forms longitudinally on many nematodes.
In the Caenorhabditis elegans
nematode
they are present in the L1, dauer
(an alternative long living larvae stage where the nematode is dormant) and adult stages. The alae is most pronounced during the dauer larval stage
and not present in the L2, and L3 C. elegans
stages.
The term ‘alae’ is derived from ala
, describing either one of the pair of ridges that forms on a nematode
or an individual crease found on an individual ridge. The term ‘ala’ is rarely used in describing the alae and scientific journals use the term ‘alae’ both singularly and in the plural.
where a fibrous ribbon of a zona pellucida
(ZP) domain protein
is produced. In C. elegans
many of these proteins are termed CUT-1. The CUT refers to cuticulins which are the various proteins that are not solubilised by both reducing agents and detergent
s made insoluble by the nature of their crosslinks.
Described as a matrix that appears to be holding the two sides of the collagen
ous cuticle
together for strengthening it should also be interpreted as a matrix separating the cuticle thereby exposing itself to the external environment. The alae is formed during an oxidative process where peroxidase
acts on protein
bound tyrosine
residues. The alae is a crease, that by the cross linking process causes radial shrinking of the seam cell secreted protein
s.
strength, nematode
movement or fat
storage. But the predominant structure of the C. elegans
alae contain the ZP
domain proteins (CUT-1, CUT-3, CUT-5). The ZP domain had been termed ‘the sequence in search of a function’ and has been given the functional role of matrix assembly and also putatively, functions in pheromone
and olfactory signal transduction
. Despite the structural nature of the ZP
domain, it is not the ideal protein for strength alone. Wherever ZP
domains are found, they are found in definite or putative association with signal transduction
accompanied by interaction with an external or hostile environment.
a ZP
domain protein of a dauer
stage nematode has been genetically associated to a target molecule found in the environment that this nematode could be using for exiting the dauer
stage. This was statistically related with a high degree of significance indicating that the alae may specifically function as a receptor site.
In the case of H. contortus
the dauer
nematode
can remain in the gastric epithelium for months and until the right signals indicating conditions outside the host are favorable for egg survival, it will then trigger resumption of development. During the dauer stage
the mouth and anal openings are sealed and neural receptors around the head retracted. The alae is more pronounced than at any other stage and remains exposed to the external environment. Triggers for exiting the dauer
state may be determined by the concentration of target molecules around the nematode
. In order to measure concentrations accurately, a very large receptor area is necessary, hence a structure such as the alae may be required.
responsive to just a handful of molecules particular to each species
of nematode
. Up to half a dozen types of receptors may be present at any one time on the alae and each type would be very numerous. The target molecules in the environment that stimulate each type of receptor may then be measured for their concentration and a threshold reached before an action is instigated. These actions may instigate entry into the dauer state (L1 alae)
, exiting of the dauer
state (pheromone
and or presence of an indicator for food availability), for sexual reproduction
where the area around the vulva
and gonads of the female and male use this family of receptors (RAM-5) where the nematode
is likely to identify that reproductive organs are in contact. And quite probably there are some other functions that we have not yet been found.
In the Caenorhabditis elegans
Caenorhabditis elegans
Caenorhabditis elegans is a free-living, transparent nematode , about 1 mm in length, which lives in temperate soil environments. Research into the molecular and developmental biology of C. elegans was begun in 1974 by Sydney Brenner and it has since been used extensively as a model...
nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
they are present in the L1, dauer
Dauer larva
Dauer describes an alternative developmental stage of nematode worms, particularly Caenorhabditis elegans whereby the larva goes into a type of stasis and can survive harsh conditions. It may also be equivalent to the infective stage of parasitic nematode larvae...
(an alternative long living larvae stage where the nematode is dormant) and adult stages. The alae is most pronounced during the dauer larval stage
Dauer larva
Dauer describes an alternative developmental stage of nematode worms, particularly Caenorhabditis elegans whereby the larva goes into a type of stasis and can survive harsh conditions. It may also be equivalent to the infective stage of parasitic nematode larvae...
and not present in the L2, and L3 C. elegans
Caenorhabditis elegans
Caenorhabditis elegans is a free-living, transparent nematode , about 1 mm in length, which lives in temperate soil environments. Research into the molecular and developmental biology of C. elegans was begun in 1974 by Sydney Brenner and it has since been used extensively as a model...
stages.
Ala
Ala may refer to:* Ala , a female demon in the Serbian and Bulgarian mythology* Ala , an Alusi in Odinani* Ala , a Republican-period, largely infantry, formation of 5,400 men...
, describing either one of the pair of ridges that forms on a nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
or an individual crease found on an individual ridge. The term ‘ala’ is rarely used in describing the alae and scientific journals use the term ‘alae’ both singularly and in the plural.
Structure
The alae is formed by the hypodermal seam cellsHypodermis
The hypodermis, also called the hypoderm, subcutaneous tissue, or superficial fascia is the lowermost layer of the integumentary system in vertebrates. Types of cells that are found in the hypodermis are fibroblasts, adipose cells, and macrophages...
where a fibrous ribbon of a zona pellucida
Zona pellucida
The zona pellucida is a glycoprotein membrane surrounding the plasma membrane of an oocyte. It is a vital constitutive part of the latter, external but of essential importance to it...
(ZP) domain protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
is produced. In C. elegans
Caenorhabditis elegans
Caenorhabditis elegans is a free-living, transparent nematode , about 1 mm in length, which lives in temperate soil environments. Research into the molecular and developmental biology of C. elegans was begun in 1974 by Sydney Brenner and it has since been used extensively as a model...
many of these proteins are termed CUT-1. The CUT refers to cuticulins which are the various proteins that are not solubilised by both reducing agents and detergent
Detergent
A detergent is a surfactant or a mixture of surfactants with "cleaning properties in dilute solutions." In common usage, "detergent" refers to alkylbenzenesulfonates, a family of compounds that are similar to soap but are less affected by hard water...
s made insoluble by the nature of their crosslinks.
Described as a matrix that appears to be holding the two sides of the collagen
Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...
ous cuticle
Cuticle
A cuticle , or cuticula, is a term used for any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticles" are non-homologous; differing in their origin, structure, function, and chemical composition...
together for strengthening it should also be interpreted as a matrix separating the cuticle thereby exposing itself to the external environment. The alae is formed during an oxidative process where peroxidase
Peroxidase
Peroxidases are a large family of enzymes that typically catalyze a reaction of the form:For many of these enzymes the optimal substrate is hydrogen peroxide, but others are more active with organic hydroperoxides such as lipid peroxides...
acts on protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
bound tyrosine
Tyrosine
Tyrosine or 4-hydroxyphenylalanine, is one of the 22 amino acids that are used by cells to synthesize proteins. Its codons are UAC and UAU. It is a non-essential amino acid with a polar side group...
residues. The alae is a crease, that by the cross linking process causes radial shrinking of the seam cell secreted protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s.
Function
The function of the alae is not yet clear. It is generally given a function related to cuticleCuticle
A cuticle , or cuticula, is a term used for any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticles" are non-homologous; differing in their origin, structure, function, and chemical composition...
strength, nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
movement or fat
Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...
storage. But the predominant structure of the C. elegans
Caenorhabditis elegans
Caenorhabditis elegans is a free-living, transparent nematode , about 1 mm in length, which lives in temperate soil environments. Research into the molecular and developmental biology of C. elegans was begun in 1974 by Sydney Brenner and it has since been used extensively as a model...
alae contain the ZP
Zona pellucida
The zona pellucida is a glycoprotein membrane surrounding the plasma membrane of an oocyte. It is a vital constitutive part of the latter, external but of essential importance to it...
domain proteins (CUT-1, CUT-3, CUT-5). The ZP domain had been termed ‘the sequence in search of a function’ and has been given the functional role of matrix assembly and also putatively, functions in pheromone
Pheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...
and olfactory signal transduction
Signal transduction
Signal transduction occurs when an extracellular signaling molecule activates a cell surface receptor. In turn, this receptor alters intracellular molecules creating a response...
. Despite the structural nature of the ZP
Zona pellucida
The zona pellucida is a glycoprotein membrane surrounding the plasma membrane of an oocyte. It is a vital constitutive part of the latter, external but of essential importance to it...
domain, it is not the ideal protein for strength alone. Wherever ZP
Zona pellucida
The zona pellucida is a glycoprotein membrane surrounding the plasma membrane of an oocyte. It is a vital constitutive part of the latter, external but of essential importance to it...
domains are found, they are found in definite or putative association with signal transduction
Signal transduction
Signal transduction occurs when an extracellular signaling molecule activates a cell surface receptor. In turn, this receptor alters intracellular molecules creating a response...
accompanied by interaction with an external or hostile environment.
Function based on genetic data of the H. Contortus dauer nematode
In the parasitic nematode Haemonchus contortusHaemonchus contortus
Haemonchus contortus, also known as red stomach worm, wire worm or Barber's pole worm, is very common parasite and one the most pathogenic nematode of ruminants. Adult worms are attached to abomasal mucosa and feed on the blood...
a ZP
Zona pellucida
The zona pellucida is a glycoprotein membrane surrounding the plasma membrane of an oocyte. It is a vital constitutive part of the latter, external but of essential importance to it...
domain protein of a dauer
Dauer larva
Dauer describes an alternative developmental stage of nematode worms, particularly Caenorhabditis elegans whereby the larva goes into a type of stasis and can survive harsh conditions. It may also be equivalent to the infective stage of parasitic nematode larvae...
stage nematode has been genetically associated to a target molecule found in the environment that this nematode could be using for exiting the dauer
Dauer larva
Dauer describes an alternative developmental stage of nematode worms, particularly Caenorhabditis elegans whereby the larva goes into a type of stasis and can survive harsh conditions. It may also be equivalent to the infective stage of parasitic nematode larvae...
stage. This was statistically related with a high degree of significance indicating that the alae may specifically function as a receptor site.
In the case of H. contortus
Haemonchus contortus
Haemonchus contortus, also known as red stomach worm, wire worm or Barber's pole worm, is very common parasite and one the most pathogenic nematode of ruminants. Adult worms are attached to abomasal mucosa and feed on the blood...
the dauer
Dauer larva
Dauer describes an alternative developmental stage of nematode worms, particularly Caenorhabditis elegans whereby the larva goes into a type of stasis and can survive harsh conditions. It may also be equivalent to the infective stage of parasitic nematode larvae...
nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
can remain in the gastric epithelium for months and until the right signals indicating conditions outside the host are favorable for egg survival, it will then trigger resumption of development. During the dauer stage
Dauer larva
Dauer describes an alternative developmental stage of nematode worms, particularly Caenorhabditis elegans whereby the larva goes into a type of stasis and can survive harsh conditions. It may also be equivalent to the infective stage of parasitic nematode larvae...
the mouth and anal openings are sealed and neural receptors around the head retracted. The alae is more pronounced than at any other stage and remains exposed to the external environment. Triggers for exiting the dauer
Dauer larva
Dauer describes an alternative developmental stage of nematode worms, particularly Caenorhabditis elegans whereby the larva goes into a type of stasis and can survive harsh conditions. It may also be equivalent to the infective stage of parasitic nematode larvae...
state may be determined by the concentration of target molecules around the nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
. In order to measure concentrations accurately, a very large receptor area is necessary, hence a structure such as the alae may be required.
Postulated function
The alae appears to be a neural receptorReceptor (biochemistry)
In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...
responsive to just a handful of molecules particular to each species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
. Up to half a dozen types of receptors may be present at any one time on the alae and each type would be very numerous. The target molecules in the environment that stimulate each type of receptor may then be measured for their concentration and a threshold reached before an action is instigated. These actions may instigate entry into the dauer state (L1 alae)
Dauer larva
Dauer describes an alternative developmental stage of nematode worms, particularly Caenorhabditis elegans whereby the larva goes into a type of stasis and can survive harsh conditions. It may also be equivalent to the infective stage of parasitic nematode larvae...
, exiting of the dauer
Dauer larva
Dauer describes an alternative developmental stage of nematode worms, particularly Caenorhabditis elegans whereby the larva goes into a type of stasis and can survive harsh conditions. It may also be equivalent to the infective stage of parasitic nematode larvae...
state (pheromone
Pheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...
and or presence of an indicator for food availability), for sexual reproduction
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
where the area around the vulva
Vulva
The vulva consists of the external genital organs of the female mammal. This article deals with the vulva of the human being, although the structures are similar for other mammals....
and gonads of the female and male use this family of receptors (RAM-5) where the nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
is likely to identify that reproductive organs are in contact. And quite probably there are some other functions that we have not yet been found.