Do fungi have a nucleus? some of the interesting facts

Introduction

Do fungi have a nucleus? Yes, it has a prominent nucleus. It is an eukaryotic cell and possesses a nucleus as well as other cell organelles. Fungi has its own kingdom. Though they have a cell wall, they are achlorophyllous. They are eco-warriors of the earth.

Fungi play a major role in trapping carbon dioxide fixed by plants into the soil preventing its return to the atmosphere. This kingdom includes the smallest single-cell fungi ‚Äďthe yeast. The largest is the honey mushroom. The study of fungi is called mycology.

Fungi and the concept of the nucleus

Nucleus

  • All fungi are eukaryotic. They have a cell wall, plasma membrane, cytoplasm and nucleus.
  • The nucleus is membrane-bound. DNA of the nucleus is wrapped around histone protein. The fungal hyphae are generally multinucleate.
  • Many fungi during their life cycle contain two different nuclei each with different genetic content.
  • Based on the number of nuclei per cell the fungi can be monokaryotic, dikaryotic and multinucleate.
  • In a dikaryotic (two-nucleus) cell the nuclei can be homokaryotic. This means both the nuclei belong to the same strain of fungi.
  • When nuclei belong to different strains of fungi then¬† it is referred to as
  • The fungal¬†nucleus is haploid i.e., it contains only one set of chromosomes in the nucleus.
  • During the sexual mode of reproduction fusion of the nucleus takes place (karyogamy).

Control centre of Eukaryotic cell

The nucleus of an eukaryotic cell is often referred to as the brain of the cell. It decides all the activities of the cell.

Structure

Nuclear envelope

  • The nucleus is surrounded by a double membrane. It controls the nucleocytoplasmic interactions.¬† The space between the double membranes of the nuclear envelope is called the perinuclear space.
  • The outer membrane of the nuclear envelope is continuous with the Endoplasmic reticulum (ER)¬† in the cytoplasm.
  • The nuclear membrane has pores. These pores help in the movement of RNA synthesized in the nucleoplasm from DNA during transcription. Transcription is the process by which the genetic information stored in the DNA is copied to the RNA.

Nucleoplasm

The nuclear membrane encloses a semi-fluid, colloidal ground substance. It contains the Nucleolus and Chromatin network. 

Nucleolus

Acts as a nuclear skeleton and maintains the shape of the nucleus.

Nucleolus

It is a non-membrane-bound, spherical structure. Associated with the nuclear organizing structure (NOR) of the nuclear chromosomes. It is a site for the synthesis of ribosomal RNA. The number of nucleolus is higher in protein-synthesizing cells.

Chromatin network

It is made up of nucleoprotein fibres. Prior to cell division, these structures condense into chromosomes. this contains genetic material DNA and histone protein.

Exploring basic fungal nucleus

The fungal nucleus is the control centre of the cell and plays an important role in the various cellular processes. It provides a unique model for the study of fungal evolution and adaptability.

 Key characteristics and function

  • Fungal hyphae are multinucleate. This condition arises due to the absence of cytokinesis after nuclear divisions.
  • The morphology of fungal nuclei is variable. Wandering nuclei are spindle-shaped while moving through the septum it is dumbbell-shaped. Those nuclei moving through hyphae are thin thread or stretched.
  • The nuclei are haploid. They freely undergo variations and mutations.
  • A fungal nucleus in heterokaryons shows competition and combat for nutritional supplements. This is possible because the nuclei mix freely in the cytoplasm.
  • Nuclei play a major role in heredity. It can control the activation and repression of specific genes.
  • The fungal nucleus contains genetic information for the synthesis of proteins. It helps in passing genetic information to the next generation.
  • The nuclear division in fungi is through mitosis. This ensures equal distribution of genetic material during cell division.
  • The nucleus helps in maintaining the structural integrity of the fungal cells. It controls the synthesis of the cell wall, the functioning of cell organelles and the overall stability of the cell.
  • Numerous nuclei of DNA¬† serve as a storehouse of nitrogen and phosphorous in fungal cells.
  • ¬†When nitrogen and phosphorous become limiting fungal growth is affected. The hyphal tip triggers the selective breakdown of the nucleus. Thus the breakdown products serve as a source of growth and continuity.

The coenocytic exception: Fungi without individual nuclei

Fungi consist of a filamentous network of thin fibres called hyphae. The collective name of hyphae is mycelium. Higher forms of fungi have cross walls called septa, such hyphae are called septate.

Hyphae lacking cross walls are unseptate hyphae, found in lower fungi.

In aseptate hyphae, the cytoplasm is continuous throughout the hyphae. The septae or cross walls are not formed after nuclear divisions. Such multinucleate hyphae are called coenocytic hyphae.

 The cells in septate hyphae may have one, two or more nuclei.

Uninucleate septate hyphae are called monokaryotic, and cells with two nuclei are called dikaryotic.  Cells with many nuclei are called multinucleates. In septate hyphae, septa are laid down after nuclear divisions. Such multinucleate hyphae are called acoenocytic hyphae.

Q&A

1. Does fungi have a nucleus?

Fungi is an eukaryotic organism and it possess a nucleus.

2. Do mushrooms have a nucleus?

Yes, mushrooms belong to the Kingdom of fungi and it has a nucleus.

3. Do fungi contain a nucleus?

Yes, fungi contain many nuclei in their cytoplasm.

4. Do fungi have a nucleus in their cells?

Yes, fungi have a nucleus in their cells.

5. Does fungi have a nucleus in their cells?

 Yes, fungi have a nucleus in their cells.

6. Does fungi have a nucleus yes or no?

Yes, fungi have a nucleus.

7. Do all fungi have a nucleus?

All fungi have a nucleus. 

Summary

  • Do fungi have a nucleus? Yes, being a eukaryote it has a nucleus. Fungi are included in a separate kingdom. The study of fungi is mycology.
  • Fungi are achlorophyllous and contain cell wall, cell membrane, cytoplasm, nucleus and other cell organelles.
  • Fungi can be unicellular like yeast. The largest is the honey mushroom.
  • Fungi consist of a filamentous network of thin fibres called hyphae.
  • The collective form of hyphae is mycelium. Hyphae with cross walls are septate. Hyphae without a cross wall are aseptate hyphae.
  • The aseptate hyphae are multinucleate and are called coenocytic hyphae. The septate, multinucleate hyphae are known as acoenocytic hyphae.
  • The nucleus of a fungi is membrane-bound and contains DNA and histone proteins.
  • Fungal nucleus is haploid i.e., it contains only one set of chromosomes in the nucleus.
  • The fungal nucleus shows variable morphology.
  • It is spindle-shaped when moving in the cytoplasm. They look stretched when passing through hyphae.
  • They look like dumbbells when passing through perforated septa.
  • The nuclear DNA stores nitrogen and phosphorous. When these nutrients are limiting the nucleus is broken down. Nutrients are utilized for the growth of hyphae.
  • The fungal nucleus contains genetic information for the synthesis of proteins. It helps in passing genetic information to the next generation.

Reference 

Fungi ‚Äď A Description of their morphological features and evolutionary development¬† By¬† Gaumann E.A.

Written By: Ahana Mitra