Penicillium

Penicillium is a type of fungus, which is commonly known as green or blue mould. This fungus can be divided into 300 distinct species. Notably, these fungi are essential for a wide range of medicinal purposes. Furthermore, people also use them in the creation of organic acids and cheese.

However, before you can appreciate the various characteristics of penicillium fungi, you must know about its classification and division. Read on to understand its life cycle, structure and reproductive traits, which are vital for your NEET curriculum. Without such knowledge, your biology preparation for competitive examinations like NEET may be incomplete.

The following table outlines the fungus’s classification in detail.

Penicillium Classification

Domain

Eukaryota

Kingdom

Fungi

Phylum

Ascomycota

Class

Eurotiomycetes 

Order

Eurotiales

Family 

Trichocomaceae

Genus

Penicillium


Penicillium Diagram

The diagram above showcases the various structures, namely monoverticillate, biverticillate, terverticillate and quaterverticillate in penicillium. 

Characteristics of Penicillium

The fungus exhibits the following characteristics, from which you can also glean its structure.

  • Cell wall comprises of chitin and glucose polysaccharide.

  • Multicellular mycelium defines the vegetative penicillium structure.

  • Thread-like filamentous, branched and multinucleated structures make up the mycelium. These are also known as hyphae.

  • Conidia production occurs in basipetal order, which means that the base holds the youngest conidium.

  • The cell relies on the septa’s central pore to maintain cytoplasmic continuity.

  • Food storage occurs in the form of oil globules.

  • Ascospores represent endogenous sexual spores.

  • Conidiophores represent asexual spores created exogenously.

  • A few of the mycelia may form deeper into the cell’s substratum, primarily to derive food.

Penicillium Reproduction

Reproduction can occur by vegetative, sexual or asexual processes. The first form of reproduction is the easiest to understand, while others involve some complex steps.

Sexual Reproduction

Sexual reproduction relies on the formation of ascospores. Here are some salient features of sexual reproduction in penicillium.

  • Penicillium can be either homothallic (male and female sex organs in the same thallus) or heterothallic (male and female sex organs present on different thallus).

  • The female sex organ is ascogonium, while the male one is referred to as antheridium.

  • Cells from vegetative mycelium form a single ascogonium cell, which, in turn, undergoes nuclear division. After division, 32 to 64 nuclei are created.

  • The antheridium branch under development coils around this ascogonium.

  • Post maturation, the ascogonial wall touches and fuses with the bending antheridium. Without the presence of cell walls, the cytoplasm from male and female cells mix, undergoing plasmogamy.

  • The ascogonium walls repeatedly divided, creating several binucleate cells. These cells are positioned one above the other.

  • The last dikaryotic cell formed through such ascogonium divisions grows large, leading to the creation of an ascus cell.

  • Diploid zygotes undergo meiosis and mitosis to create 8 distinct ascospores.

  • As soon as the ascus wall dissolves, these ascospores are released and attached on suitable substratum.

  • After germ tube formation, these ascospores develop into branched mycelium.

This completes a sexual reproduction process for penicillium.

Asexual Reproduction

Asexual reproduction is primarily carried out by conidiophores. Here is the process by which such reproduction occurs.

  • Branched or unbranched conidiophores separate into metulae.

  • Flask-like phialide cells form at the end of such metulae, which gives rise to conidia.

  • Through mitosis, these phialide cells form a conidium. Additional mitotic divisions push the first conidium outwards, driving the formation of a second conidium. This process repeats several times.

  • Such conidia can have a variety of shapes and colours. Possible colours include yellow, blue and green. It can come in elliptical or oval shapes.

  • Detachment of conidia occurs after maturity, after which it is dispersed by the wind.

  • They attach to suitable surfaces and undergo germination.

  • Germination occurs through germ tube formation, after multiple mitotic nucleus divisions. This process eventually gives rise to a branched and mature mycelium.

Lastly, we must learn about the vegetative reproduction process among penicillium species.

Vegetative Reproduction

The simplest form of reproduction, this process occurs accidentally. Accidental fragmentation of the mycelium is responsible for such propagation in penicillium. Each of these fragments grows just like its mother mycelium.

Quick Question

Q. What is the name of the male and female organ in penicillium fungus?

Ans. The male sex organ is antheridium, while the female sex organ is known as ascogonium. 

Economic Importance of Penicillium

Now that you know all about penicillium and its propagational methods, let us take a look at some of its real-world usage.

  • Antibiotics – Alexander Fleming was able to isolate the penicillin antibiotic from penicillium in 1929. This discovery became the cornerstone for the treatment of bacterial infections, so much so that it is still used across the world today.

  • Making Cheese – Penicillium species are essential additives for the creation of certain cheese, such as Camembert, blue cheese, Roquefort cheese and Brie cheese. 

  • Antifungal Medication – This fungus is a crucial element in many antifungal drugs as well. 

Biology Preparation for the Best Results

Biology is a crucial part of your NEET preparation. Therefore, ensure you focus greatly on learning the characteristics of penicillium. Memorising its classification and characteristics can fetch you the easy marks in this competitive examination. 

However, while studying about the life cycle of penicillium, do not forget about your health. Students often spend an inordinate amount studying, so much so that they neglect necessities like food and sleep. Make sure that you do not make the same mistake. While preparations are important, adequate rest and a balanced diet are also crucial for long-term success.

All the best!

FAQ (Frequently Asked Questions)

1. Where are Penicillium Naturally Found?

Ans. Penicillium naturally occurs in decaying soil, vegetation and air. These fungal growths can spoil food items and colonise leather products. Furthermore, they lead to the formation of mould inside houses where adequate moisture is present.

2. How Can You Identify Penicillium by Its Structure?

Ans. Identifying penicillium from its structure is simple, as they are characterised by their branching structures. Look for an elongated body, which ends in flask-shaped clusters, known as phialides.

3. What are the Three Reproductive Processes of Penicillium?

Ans. Penicillium can propagate in three ways which are sexual, asexual and vegetative. This last procedure only occurs in accidental cases, where the mycelium fragments into two or more parts.