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Ashbya gossypii
 
 
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Ashbya gossypii is a filamentous fungus
Fungus

A fungus is a Eukaryote organism that is a member of the Kingdom Fungi . The fungi are a monophyletic group, also called the Eumycota , that is phylogeny distinct from the morphologically similar slime molds and water molds ....
 or mold
Mold

Molds include all species of microscopic fungi that grow in the form of Multicellular organism filaments, called hyphae. In contrast, microscopic fungi that grow as single cells are called yeasts....
 closely related to yeast, but growing exclusively in a filamentous way. It was originally isolated from cotton
Cotton

Cotton is a soft, staple fiber that grows in a form known as a boll around the seeds of the cotton plant a shrub native to tropical and subtropical regions around the world, including the Americas, India and Africa....
 as a pathogen
Pathogen

A pathogen , infectious agent, or germ, is a biological agent that causes disease or illness to its Host .There are several substrates and pathways whereby pathogens can invade a host; the principal pathways have different episodic time frames, but soil contamination has the longest or most persistent potential for harboring...
 causing stigmatomycosis
Stigmatomycosis

The term Stigmatomycosis is the general name for a fungal disease that occurs in a number of crops, such as cotton, soybean, pecan, pomegranate, citrus, and pistachio....
 by Ashby and Novell in 1926. This disease affects the development of hair cells in cotton bolls and can be transmitted to citrus fruits, which thereupon dry out and collapse (dry rot disease). In the first part of the 20th century, A.






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Ashbya gossypii is a filamentous fungus
Fungus

A fungus is a Eukaryote organism that is a member of the Kingdom Fungi . The fungi are a monophyletic group, also called the Eumycota , that is phylogeny distinct from the morphologically similar slime molds and water molds ....
 or mold
Mold

Molds include all species of microscopic fungi that grow in the form of Multicellular organism filaments, called hyphae. In contrast, microscopic fungi that grow as single cells are called yeasts....
 closely related to yeast, but growing exclusively in a filamentous way. It was originally isolated from cotton
Cotton

Cotton is a soft, staple fiber that grows in a form known as a boll around the seeds of the cotton plant a shrub native to tropical and subtropical regions around the world, including the Americas, India and Africa....
 as a pathogen
Pathogen

A pathogen , infectious agent, or germ, is a biological agent that causes disease or illness to its Host .There are several substrates and pathways whereby pathogens can invade a host; the principal pathways have different episodic time frames, but soil contamination has the longest or most persistent potential for harboring...
 causing stigmatomycosis
Stigmatomycosis

The term Stigmatomycosis is the general name for a fungal disease that occurs in a number of crops, such as cotton, soybean, pecan, pomegranate, citrus, and pistachio....
 by Ashby and Novell in 1926. This disease affects the development of hair cells in cotton bolls and can be transmitted to citrus fruits, which thereupon dry out and collapse (dry rot disease). In the first part of the 20th century, A. gossypii and two other fungi causing stigmatomycosis (Eremothecium coryli
Nematospora coryli

Nematospora coryli is a plant pathogen that causes stigmatomycosis. It is cultivated on potato dextrose agar and grows as yeast-like oval or spherical budding cells either isolated or in short chains and has few hyphae which are septate at maturity....
, Aureobasidium pullulans
Aureobasidium pullulans

Aureobasidium pullulans is a plant pathogen, causing stigmatomycosis on cotton. It can be cultivated on potato dextrose agar where it produces smooth, faint pink yeast-like colonies that are covered with a slimy mass of spores....
) made it virtually impossible to grow cotton in certain regions of the subtropics, causing severe economical losses. Control of the spore transmitting insects - (Dysdercus suturellus) and - permitted to fully eradicate infections. It was recognized that A. gossypii is a natural overproducer of riboflavin
Riboflavin

Riboflavin , also known as vitamin B2, is an easily absorbed micronutrient with a key role in maintaining health in humans and animals....
, also known as vitamin B2, which protects its spores against ultraviolet light. This made it an interesting organism for industries, where genetically modified strains are still used to produce this vitamin
Vitamin

A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. A compound is called a vitamin when it cannot be biosynthesis in sufficient quantities by an organism, and must be obtained from the diet....
.

A. gossypii as a model organism

A few years ago, A. gossypii became recognized as an attractive model
Model organism

A model organism is a species that is extensively studied to understand particular biology phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms....
 to study the growth of long and multinucleate
Multinucleate

Multinucleate cells have more than one Cell nucleus per Cell , which is the result of nuclear division not being followed by cytokinesis. As a consequence, multiple nuclei share one common cytoplasm....
 fungal cells (hypha
Hypha

A hypha is a long, branching filamentous cell of a fungus, and also of unrelated Actinobacteria. In fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium....
e) because of its small genome
Genome

In classical genetics, the genome of a diploid organism including eukarya refers to a full set of chromosomes or genes in a gamete; thereby, a regular somatic cell contains two full sets of genomes....
, haploid
Ploidy

Ploidy is the number of complete sets of non-homologous chromosomes in a biological cell. In humans, the somatic cells that comprise the body are diploid , but sex cells are haploid....
 nuclei
Cell nucleus

In cell biology, the nucleus , also sometimes referred to as the "control center", is a membrane-enclosed organelle found in all eukaryote cell ....
, and efficient gene targeting
Gene targeting

Gene targeting is a genetics technique that uses Genetic recombination to change an endogenous gene. The method can be used to delete a gene, remove exons, and introduce point mutations....
 methods. It is generally assumed that a better understanding of filamentous fungal growth will greatly stimulate the development of novel fungicide
Fungicide

Fungicides are chemical compounds or biological organisms used to kill or inhibit fungus or fungal spores. Fungi can cause serious damage in agriculture, resulting in critical losses of Crop yield, quality and profit....
s. The use of Ashbya gossypii as a model organism
Model organism

A model organism is a species that is extensively studied to understand particular biology phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms....
 is particularly promising because of the high level of gene order
Gene orders

Gene orders is the permutation of genome arrangement. So far a fair amount of work trying to describe whether gene orders evolve according to a molecular clock or in jumps ....
 conservation (synteny
Synteny

In classical genetics, synteny describes the physical co-localization of Locus on the same chromosome within an individual or species. The concept is related to genetic linkage: Linkage between two loci is established by the observation of lower-than-expected recombination frequencies between two or more loci....
) between the genome
Genome

In classical genetics, the genome of a diploid organism including eukarya refers to a full set of chromosomes or genes in a gamete; thereby, a regular somatic cell contains two full sets of genomes....
s of A. gossypii and the yeast Saccharomyces cerevisiae
Saccharomyces cerevisiae

Saccharomyces cerevisiae is a species of budding yeast. It is perhaps the most useful yeast owing to its use since ancient times in baking and brewing....
.

Genome

The complete sequencing
Sequencing

In genetics and biochemistry, sequencing means to determine the primary structure of an unbranched biopolymer. Sequencing results in a symbolic linear depiction known as a sequence which succinctly summarizes much of the atomic-level structure of the sequenced molecule....
 and annotation
Annotation

An annotation is an addition made to pragmatics in a book, document, online record, video, or other information.Commonly this is used, for example, in draft documents, where another reader has written notes about the quality of a document at a certain point, "marginalia", or perhaps just underlined or highlighted passages....
 of the entire A. gossypii genome
Genome

In classical genetics, the genome of a diploid organism including eukarya refers to a full set of chromosomes or genes in a gamete; thereby, a regular somatic cell contains two full sets of genomes....
, as published in 2004, was initiated when a significant degree of gene
Gene

A gene is the basic unit of heredity in a living organism. All living things depend on genes. Genes hold the information to build and maintain their cell and pass genetic trait to offspring....
 synteny
Synteny

In classical genetics, synteny describes the physical co-localization of Locus on the same chromosome within an individual or species. The concept is related to genetic linkage: Linkage between two loci is established by the observation of lower-than-expected recombination frequencies between two or more loci....
 was observed in preliminary studies in comparison to the genome of budding yeast, Saccharomyces cerevisiae
Saccharomyces cerevisiae

Saccharomyces cerevisiae is a species of budding yeast. It is perhaps the most useful yeast owing to its use since ancient times in baking and brewing....
. This not only helped to improve gene annotation of S. cerevisiae, but also allowed the reconstruction
Ancestral Reconstruction

DNA and Protein reconstruction Originally proposed by Pauling and Zuckerkandl in 1963 the reconstruction of ancient proteins and DNA sequences has only recently become a significant scientific endeavor....
 of the evolutionary history of both organisms. A. gossypii and S. cerevisiae originate from a common ancestor
Ancestor

An ancestor is a parent or the parent of an ancestor .Two individuals have a genetics relationship if one is the ancestor of the other, or if they share a common ancestor....
 which carried about 5000 genes. Divergence
Genetic divergence

Genetic divergence is the process of one species diverging over time into more than one species. Passing small random advantages characteristic changes over time from one generation to the next generations....
 of these two close relatives started some 100 million years ago. One branch of evolution involving up to 100 viable genome rearrangements (translocations
Chromosomal translocation

In genetics, a chromosome translocation is a chromosome abnormality caused by rearrangement of parts between nonhomologous chromosomes. A fusion gene may be created when the translocation joins two otherwise separated genes, an event which is common in cancer....
 and inversions
Chromosomal inversion

An inversion is a chromosome rearrangement in which a segment of a chromosome is reversed end to end. An inversion occurs when a single chromosome undergoes breakage and rearrangement within itself....
), a few million base pair
Base pair

In molecular biology, two nucleotides on opposite complementarity DNA or RNA strands that are connected via hydrogen bonds are called a base pair ....
 changes, and a limited number of gene deletions, duplications
Gene duplication

Gene duplication is any duplication of a region of DNA that contains a gene; it may occur as an error in homologous recombination, a retrotransposon event, or duplication of an entire chromosome....
 and additions lead to modern A. gossypii with its 4718 protein-coding genes and 9.2 million base pairs (smallest genome of a free-living eukaryote yet characterized) spread over seven chromosomes. The genome of S. cerevisiae underwent a more eventful evolution, which includes a whole-genome duplication.

Despite the long evolutionary history and of the two organisms and fundamentally different ways of growth and development, the complete synteny
Synteny

In classical genetics, synteny describes the physical co-localization of Locus on the same chromosome within an individual or species. The concept is related to genetic linkage: Linkage between two loci is established by the observation of lower-than-expected recombination frequencies between two or more loci....
 map of both genomes reveals that 95 % of A. gossypii genes are orthologs
Homology (biology)

In evolutionary biology, homology refers to any similarity between characteristics that is due to their common descent. The word homologous derives from the ancient Greek ??????e??, 'to agree'....
 of S. cerevisiae genes and 90 % map within blocks of synteny (syntenic homologs
Homology (biology)

In evolutionary biology, homology refers to any similarity between characteristics that is due to their common descent. The word homologous derives from the ancient Greek ??????e??, 'to agree'....
).

Growth, Development and Morphology

The A. gossypii life cycle
Biological life cycle

A life cycle is a period involving one generation of an organism through means of reproduction, whether through asexual reproduction or sexual reproduction....
 starts with the only known phase of isotropic
Isotropy

Isotropy is uniformity in all directions. Precise definitions depend on the subject area. The word is made up from Greek iso and tropos ....
 growth in wild type
Wild type

Wild type, sometimes written wildtype or wild-type, is the typical form of an organism, strain, gene, or characteristic as it occurs in nature....
: germination
Germination

Germination is the process whereby growth emerges from a period of dormancy. The most common example of germination is the sprouting of a seedling from a seed of an flowering plant or gymnosperm....
 of the haploid
Ploidy

Ploidy is the number of complete sets of non-homologous chromosomes in a biological cell. In humans, the somatic cells that comprise the body are diploid , but sex cells are haploid....
 spore
Spore

In biology, a spore is a reproduction structure that is adapted for biological dispersal and surviving for extended periods of time in unfavorable conditions....
 to form a germ bubble. This is followed by apical
Apical

Apical, from the Latin apex meaning to be at the apex or tip, may refer to:*Apical consonant, a consonant produced with the tip of the tongue...
 growth, extending two germ tubes in succession on opposing sites of the germ bubble. More axes of polarity are established with lateral branch formation in young mycelium
Mycelium

Mycelium is the Vegetative reproduction part of a fungus, consisting of a mass of branching, thread-like hyphae. The mass of hyphae is sometimes called shiro, especially within the Fairy rings fungi....
. Maturation is characterized by apical branching (tip splitting) and a dramatic increase of growth speed (up to 200 µm/h at 30°C), which enables it to cover an 8 cm Petri dish
Petri dish

A Petri dish is a shallow glass or plastic cylindrical lidded dish that microbiologists use to microbiological culture cell s. It was named after Germany bacteriologist Julius Richard Petri, who invented it when working as an assistant to Robert Koch....
 of full medium
Growth medium

A growth medium or culture medium is a liquid or gel designed to support the growth of microorganisms or Cell s , or small plants like the moss Physcomitrella patens ....
 in about 7 days. Sporulation is thought to be induced by nutrient
Nutrient

A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment....
 deprivation, leading to contraction at the septa
Septum (disambiguation)

Septum or septa may refer to:* Septum, a partition of two cavities or spaces* Septum , in marine biology, a thin membrane separating each shell chamber in cephalopods that retained their external shell...
, cytokinesis
Cytokinesis

Cytokinesis is the process where the cytoplasm of a single eukaryotic cell is divided to form two daughter cells. It usually initiates during the late stages of mitosis, and sometimes meiosis, splitting a binucleate cell in two, to ensure that chromosome number is maintained from one generation to the next....
 and subsequent abscission of sporangia
Sporangium

A sporangium is a plant or fungus structure producing and containing spores. Sporangia occur in Flowering plant, gymnosperms, ferns, fern allies, bryophytes, Algaee, and Fungus....
 which contain up to 8 haploid
Ploidy

Ploidy is the number of complete sets of non-homologous chromosomes in a biological cell. In humans, the somatic cells that comprise the body are diploid , but sex cells are haploid....
 spores. Hypha
Hypha

A hypha is a long, branching filamentous cell of a fungus, and also of unrelated Actinobacteria. In fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium....
e are compartmentalized by septa
Septum (disambiguation)

Septum or septa may refer to:* Septum, a partition of two cavities or spaces* Septum , in marine biology, a thin membrane separating each shell chamber in cephalopods that retained their external shell...
, which in young parts appear as rings that allow transfer of nuclei
Cell nucleus

In cell biology, the nucleus , also sometimes referred to as the "control center", is a membrane-enclosed organelle found in all eukaryote cell ....
 and in older parts may appear as closed discs. Compartments typically contain around eight nuclei
Cell nucleus

In cell biology, the nucleus , also sometimes referred to as the "control center", is a membrane-enclosed organelle found in all eukaryote cell ....
.

Research Interests


Mechanisms of cell polarity
Polar growth is essential for proper function of many cells. Without cell polarity many transport processes and signal perception of vision and sound would be impossible. Investigating how Ashbya gossypii hyphae maintain polarity and grow constantly into one direction will help to understand the basic processes of cell polarity.

Evolution of the cell cycle in multinucleated cells
How do cell shape, size and nuclear organization influence the function of conserved cell cycle
Cell cycle

The cell cycle, or cell-division cycle, is the series of events that take place in a cell leading to its division and duplication . In cells without a nucleus , the cell cycle occurs via a process termed binary fission....
 networks? This work examines alternative modes of transcriptional
Transcription (genetics)

Transcription is the synthesis of RNA under the direction of DNA. RNA synthesis, or transcription, is the process of transcribing DNA nucleotide sequence information into RNA sequence information....
 control, spatial organization, and post-translational regulation that were adopted for nuclear division to accurately function in the framework of a multinucleated cell.

Spatial control of mitosis
It has been discovered that a conserved family of proteins called the septins
Septins

Septins are evolutionary conserved proteins with essential functions in cytokinesis, and more subtle roles throughout the cell cycle. Much of our knowledge about septins originates from studies of budding yeast Saccharomyces cerevisiae, where they form a ring-like protein scaffold at the mother-bud neck....
 may contribute to the location of mitoses
Mitosis

Mitosis is the process in which a eukaryotic cell separates the chromosomes in its cell nucleus, into two identical sets in two daughter nuclei....
. Thus septins seem to provide instructions that direct where a mitosis takes place. This project focuses on understanding how the septins signal to the cell cycle
Cell cycle

The cell cycle, or cell-division cycle, is the series of events that take place in a cell leading to its division and duplication . In cells without a nucleus , the cell cycle occurs via a process termed binary fission....
 machinery.

Nutritional control of cyclin dependent kinase activity
It has been shown that the Cyclin
Cyclin

Cyclins are a family of proteins involved in the progression of cells through the cell cycle. They are the "regulatory subunits of the heterodimeric protein kinases that control cell cycle events."...
 dependent kinase (CDK
Cyclin-dependent kinase

Cyclin-dependent kinases belong to a group of protein kinases originally discovered as being involved in the regulation of the cell cycle. CDK9, however, is an exception, as it plays no role in cell cycle regulation....
) is phosphorylated and inhibited by the action of Swe1p (a wee1
Wee (cell cycle)

Wee is a protein that operates at the G2 phase to Metaphase Cell_cycle_checkpoint#G2_Checkpoint. Wee becomes active if errors occur in the S phase phase....
-like kinase) in response to low nutrients. This work focuses on understanding how external nutrient status is transmitted through the cell to regulate Swe1p kinase.

Basis for asynchronous mitoses in a common cytoplasm
There is some evidence proteins can be exchanged between neighboring nuclei in Ashbya cells, however, the nuclei still divide independently of their neighbors. This work involves identifying the basis for nuclear independence within a common cytoplasm
Cytoplasm

The cytoplasm is the part of a Cell that is enclosed within the plasma membrane. In eukaryote cells the cytoplasm contains organelles, such as mitochondrion, that are filled with liquid kept separate from the rest of the cytoplasm by biological membranes....
 including experiments evaluating how Spindle Pole Bodies, Nuclear Pore Complex components and/or the Endoplasmic reticulum may be involved in maintaining nuclear autonomy.

Taxonomy

Morphology

External links