Can you please define the following terms briefly?

Question

Dear friends,

I feel difficulty to find definitions of following terms:

what is gongrosira stage

what are clamp connections

what is a promycelium

what are mitospores

what is witches broom

Answer 1

I have the feeling you're studying some mycology here.  I'm not sure all definitions can be "brief" though to explain what each is.  It's been a while since my mycology class, so I had to look a few of these up myself.

what is gongrosira stage - This is where the cytoplasm is partitioned into disconnected, drying-resistant segments.  It's named for a genus of algae in which this was observed.

what are clamp connections - This is something only found in Basidiomycetes.  It's a method so that each hyphal cell gets a copy of both nuclei.   As the primary mycelium (hypha) expands, both nuclei divide - one in the primary mycelium, and one in the secondary mycelium (side growth) which will become the clamp connection.  As the primary mycelium walls off between the set of nuclei that divided in the primary mycelium, the secondary mycelium passes over the wall and fuses ("clamps") to the other side so a copy of the other nuclei can be inserted into the original cell.  The the base of the secondary mycelium creates a wall to keep both cells separated.  This looks like a "P"-shaped structure along the mycelium as it's growing and is acting as a bridge between the two cells, or just a bump on the mycellium in later stages.  Perhaps some diagrams and pictures will help with this explanation:

http://www.biologie.uni-hamburg.de/b-onl...

You can see an actual clamp connection at the top center hyphae in this link:  http://en.wikipedia.org/wiki/Image:Canth... Seeing these microscopically is a good way to differentiate between the mycelium of basidiomycetes and other fungi when you don't have fruiting bodies to look at.

what is a promycelium - This is produced by rust fungi.  These fungi don't produce basidiocarps, so the fusion of the nuclei (karyogamy) takes place in a specialized spore (teliospore).  When the teliospore germinates, a short germ tube of fixed growth size is produced - this is the promycelium.  This is where the basidiospores and sterigmata develop and where meiosis takes place.

what are mitospores - a spore where the nucleus was produced by mitosis rather than by meiosis

what is witches broom - This is abnormal growth shown by a plant - this can be in response to an irritant, chemical, or pathogen.  What happens is that the plant's cells divide in an uncontrolled fashion so abundant growth is produced from a single point.  See these photos, and you'll know how this gets it's name:  http://www.ipm.iastate.edu/ipm/hortnews/...

http://www.flickr.com/photos/30592630@N0...

http://www.ppdl.org/dd/images/witches_br...

Answer 2

what is gongrosira stage:

I`m not sure having correctly understood your first question; gongrosira stage or phase is to find in connection with a vaucheriacean xanthophyte alga ( http://en.wikipedia.org/wiki/Gongrosira )

"The Gongrosira-phase of Vaucheria appears to be an estivating/reproductive response to desiccation, in which case the resulting cells are reasonably described as akinetes (Stahl 1879; Fritsch 1935); ......"

http://findarticles.com/p/articles/mi_qa...

page 43:

http://www.blackwell-synergy.com/doi/pdf...

That`s not what you are looking for, I`m afraid. So sorry!!!

what are clamp connections:

"in many basidiomycete fungi a short lateral branch of a binucleate cell develops. This is the developing clamp connection. One of the nuclei migrates into it. Both nuclei then undergo simultaneous mitosis so that one end of the cell contains two daughter nuclei from each of the parental nuclei."

http://en.wikipedia.org/wiki/Clamp_conne...

http://cancerweb.ncl.ac.uk/cgi-bin/omd?c...

what is a promycelium:

"a short tubular outgrowth from certain germinating fungal spores that produces spores itself and then dies"

http://dictionary.reverso.net/english-de...

pics:  http://www.mycologia.org/cgi/content/ful...

what are mitospores

spores resulting from meiosis.

They may simply reproduce the parent, or may also act as gametes to fertilize a compatible partner.

http://www.iwf.de/iwf/do/mkat/createpdf....

witches broom:

"an abnormal growth of closely bunched, slender twigs at the ends of branches of various woody plants, caused by fungi, viruses, etc."

http://www.yourdictionary.com/witches-br...

example:

http://www.oardc.ohio-state.edu/cocoa/wi...

Answer 3

Genera

    * Aphanochaete

    * Arthrochaete

    * Bolbocoleon

    * Cedercreutziella

    * Chaetomnion

    * Chaetonema

    * Chaetonemopsis

    * Chaetophora

    * Chamaetrichon

    * Chlorofilum

    * Chlorotylium

    * Choreoclonium

    * Cloniophora

    * Coccobotrys

    * Crenacantha

    * Ctenocladus

    * Dermatophyton

    * Desmococcus

    * Diaphragma

    * Dicranochaete

    * Didymosporangium

    * Dilabifilum

    * Diplosphaera

    * Draparnaldia

    * Draparnaldiopsis

    * Elaterodiscus

    * Endoclonium

    * Endoderma

    * Endophyton

    * Epibolium

    * Fritschiella

    * Gongrosira

    * Gongrosirella

    * Hazenia

    * Helicodictyon

    * Herposteiron

    * Internoretia

    * Ireksokonia

    * Iwanoffia

    * Jaagiella

    * Klebahniella

    * Kymatotrichon

    * Leptosira

    * Leptosiropsis

    * Nayalia

    * Periplegmatium

    * Pilinella

    * Pleurangium

    * Pleurococcus

    * Pringsheimiella

    * Pseudendoclonium

    * Pseudochaete

    * Pseudopleurococcus

    * Pseudopringsheimia

    * Pseudulvella

    * Rhexinema

    * Skvortzoviothrix

    * Sporocladopsis

    * Stigeoclonium

    * Streptochlora

    * Stromatella

    * Syncoryne

    * Tellamia

    * Thamniochaete

    * Thamniochloris

    * Trichodiscus

    * Trichophilus

    * Trichosarcina

    * Tumulofilum

    * Uronema

    * Zoddaea

    * Zygomitus

Clamp connection

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A type of connection found within a single hyphal strand of a Basidiomycete fungus. It ensures that two adjacent hyphal cells (divided by septa) each have 2 different nuclei from mating with hyphae of another sexual type. It is used in the "nuclear shuffle" similar to that found in croziers during sexual reproduction.

Basidiomycota is one of two large phyla, that together with the Ascomycota, comprise the subkingdom Dikarya, which were in general what were called the "Higher Fungi" within the Kingdom Fungi. More specifically the Basidiomycota include mushrooms, puffballs, stinkhorns, bracket fungi, other polypores, jelly fungi, boletes, chanterelles, earth stars, smuts, bunts, rusts, mirror yeasts, and the human pathogenic yeast,Cryptococcus. Basically, Basidiomycota are filamentous fungi composed of hyphae (except for those forming yeasts), and reproducing sexually via the formation of specialized club-shaped end cells called basidia that normally bear external spores (usually four), which are specialized meiospores called basidiospores. However, some Basidiomycota reproduce asexually, and may or may not also reproduce sexually. Asexually reproducing Basidiomycota (discussed below) can be recognized as members of this phylum by gross similarity to others, by the formation of a distinctive anatomical feature (the clamp connection - see below), cell wall components, and definitively by phylogenetic molecular analysis of DNA sequence data.

Contents

[show]

    * 1 Classification

    * 2 Typical life-cycle

    * 3 Variations in life-cycles

          o 3.1 Rusts

          o 3.2 Smuts

    * 4 References

    * 5 External links

[edit] Classification

The most recent classification[2] adopted by a coalition of 67 mycologists recognizes 3 subphyla (Pucciniomycotina, Ustilaginomycotina, Agaricomycotina) and 2 other class level taxa (Wallemiomycetes, Entorrhizomycetes) outside of these, among the Basidiomycota. As now classified, the subphyla join and also cut across various obsolete taxonomic groups (see below) previously commonly used to describe various Basidiomycota.

The Basidiomycota had traditionally been divided into 2 obsolete classes, the Homobasidiomycetes (including true mushrooms); and the Heterobasidiomycetes (the Jelly, Rust and s**t fungi). Previously the entire Basidiomycota were called Basidiomycetes, an invalid class level name coined in 1959 as a counterpart to the Ascomycetes, when neither of these taxa were recognized as phyla. The terms basidiomycetes and ascomycetes are frequently used loosely to refer to Basidiomycota and Ascomycota. They are often abbreviated to "basidios" and "ascos" as mycological slang.

The Agaricomycotina (see details on that page) includes what had previously been called the Hymenomycetes (an obsolete morphological based class of Basidiomycota that formed hymenial layers on their fruitbodies), the Gasteromycetes (another obsolete class that included species mostly lacking hymenia and mostly forming spores in enclosed fruitbodies), as well as most of the jelly fungi.

The Ustilaginomycotina are most (but not all) of the former s**t fungi and along with the Exobasidiales.

The Pucciniomycotina includes the rust fungi, the insect parasitic/symbiotic genus Septobasidium, a former group of s**t fungi (in the Microbotryomycetes, which includes mirror yeasts), and a mixture of odd, infrequently seen or seldom recognized fungi, often parasitic on plants.

Two classes, Wallemiomycetes and Entorrhizomycetes cannot at present be placed in a subphylum.

[edit] Typical life-cycle

Unlike higher animals and plants which have readily recognizable male and female counterparts, Basidiomycota (except for the Rust (Pucciniales)) tend to have mutually indistinguishable, compatible haploids which are usually mycelia being composed of filamentous hyphae. Typically haploid Basidiomycota mycelia fuse via plasmogamy and then the compatible nuclei migrate into each other's mycelia and pair up with the resident nuclei. Karyogamy is delayed, so that the compatible nuclei remain in pairs, called a dikaryon. The hyphae are then said to be dikaryotic. Conversely, the haploid mycelia are called monokaryons. Often, the dikaryotic mycelium is more vigorous than the individual monokaryotic mycelia, and proceeds to take over the substrate in which they are growing. The dikaryons can be long-lived, lasting years, decades, or centuries. The monokaryons are neither male nor female. They have either a bipolar (unifactorial) or a tetrapolar (bifactorial) mating system. This results in the fact that following meiosis, the resulting haploid basidiospores and resultant monokaryons, have nuclei that are compatible with 50% (if bipolar) or 25% (if tetrapolar) of their sister basidiospores (and their resultant monokaryons) because the mating genes must differ for them to be compatible. However, there are many variations of these genes in the population, and therefore, over 90% of monokaryons are compatible with each other. It is as if there were multiple sexes.

The maintenance of the dikaryotic status in dikaryons in many Basidiomycota is facilitated by the formation of clamp connections that physically appear to help coordinate and re-establish pairs of compatible nuclei following synchronous mitotic nuclear divisions. Variations are frequent and multiple. In a typical Basidiomycota lifecycle the long lasting dikaryons periodically (seasonally or occasionally) produce basidia, the specialized usually club-shaped end cells, in which a pair of compatible nuclei fuse (karyogamy) to form a diploid cell. Meiosis follows shortly with the production of 4 haploid nuclei that migrate into 4 external, usually apical basidiospores. Variations occur, however. Typically the basidiospores are ballistic, hence they are sometimes also called ballistospores. In most species, the basidiospores disperse and each can start a new haploid mycelium, continuing the lifecycle. Basidia are microscopic but they are often produced on or in multicelled large fructifications called basidiocarps or basidiomes, or fruitbodies), variously called mushrooms, puffballs, etc. Ballistic basidiospores are formed on sterigmata which are tapered spine-like projections on basidia, and are typically curved, like the horns of a bull. In some Basidiomycota the spores are not ballistic, and the sterigmata may be straight, reduced to stubbs, or absent. The basidiospores of these non-ballistosporic basidia may either bud off, or be released via dissolution or disintegration of the basidia.

Schematic of a typical basidiocarp, the dipoid reproductive structure of a basidiomycete, showing fruiting body, hymenium and basidia.

Schematic of a typical basidiocarp, the dipoid reproductive structure of a basidiomycete, showing fruiting body, hymenium and basidia.

In summary, meiosis takes place in a diploid basidium. Each one of the four haploid nuclei migrates into its own basidiospore. The basidiospores are ballistically discharged and start new haploid mycelia called monokaryons. There are no males or females, rather there are compatible thalli with multiple compatibility factors. Plasmogamy between compatible individuals leads to delayed karyogamy leading to establishment of a dikaryon. The dikaryon is long lasting but ultimately gives rise to either fruitbodies with basidia or directly to basidia without fruitbodies. The paired dikaryon in the basidium fuse (i.e karyogamy takes place). The diploid basidium begins the cycle again.

[edit] Variations in life-cycles

Many variations occur. Some are self compatible and spontaneously form dikaryons without a separate compatible thallus being involved. These fungi are said to be homothallic, versus the normal heterothallic species with mating types. Others are secondarily homothallic, in that two compatible nuclei following meiosis migrate into each basidiospore, which is then dispersed as a pre-existing dikaryon. Often such species form only two spores per basidium, but that too varies. Following meiosis, mitotic divisions can occur in the basidium. Multiple numbers of basidiospores can result, including odd numbers via degeneration of nuclei, or pairing up of nuclei, or lack of migration of nuclei. For example, the chanterelle genus Craterellus often has 6-spored basidia, while some corticioid