page_title: Entomophthora
section_title: Reproduction
hierarchical_section_title: Entomophthora / Reproduction
caption_attribution_description: English: Title: Biology; the story of living things Identifier: biologystoryofli00hunt Year: 1937 (1930s) Authors: Hunter, George W. (George William), 1873-1948; Walter, Herbert Eugene, b. 1867; Hunter, George W. (George William), 1902- Subjects: Publisher: New York, Cincinnati [etc. ] American book company Contributing Library: MBLWHOI Library Digitizing Sponsor: MBLWHOI Library View Book Page: Book Viewer About This Book: Catalog Entry View All Images: All Images From Book Click here to view book online to see this illustration in context in a browseable online version of this book. Text Appearing Before Image: 174 ORGANISMS ILLUSTRATING RIOLOGICAL PRINCIPLES Text Appearing After Image: Great numbers of tiny spores are produced by division of the dense terminal portions of the sporangiophores. As a sporangium becomes mature an outer wall is formed and the spores turn black in color. When this outer wall breaks, the minute spores are scattered far and wide by air currents. Molds also reproduce sexually, by means of con- jugation. Rhizopus has two different strains of mycelia, one of which is called a plus ( + ) and the other a minus ( —) strain. If hyphae of two such strains come in contact with each other, zygo- spores are formed. Short, club-shaped branches are developed from the hy- phae, the dense proto- plasmic tips are cut off from the end of each by cell walls, and these "cells," each of which contains several nuclei, unite to form a zygote. The zygote with the hyphae which develop from it proba- bly represents the diploid stage of chromosome in the life cycle, the haploid stage being reached when the spores on the sporangium germinate. The fungi are of even more interest by reason of their method of nutrition. They are typically neither holozoic nor holophytic, since they live as saprophytes on dead organic materials. This means that they must absorb food materials which are supplied to them from outside sources after digesting them by means of enzymes, when absorption takes place through the plasma membrane of the cell. Alternation of Generations in the Plant Kingdom The most important difference in the life cycle between the Bryo- phytes or Mosses and lower forms, aside from a greater differentiation of the plant body, is the alternation of an asexual with that of a sexual generation in the hfe cycle. The asexual generation, which produces spores, is called the sporophyte, while the sexual generation, which Reproduction in bread mold (Rhizopus nigri- cans). Read the text and then explain the diagrEun. Note About Images Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.
context_page_description: Entomophthora is a fungal genus in the family Entomophthoraceae. Species in this genus are parasitic on flies and other two-winged insects. The genus was circumscribed by German biologist Ferdinand Cohn in 1856.
  This fungus is parasitic and undergoes a number of stages within its life cycle, these include; infection, incubation, sporulation and mummification. Within each stage, this pathogen invades the host’s body cells, utilising the insect’s nutrients allowing it to take control over the brain just before the host’s death.
  Entomophthora reproduces asexually through both budding and spores. When in the host’s body, the pathogen utilises budding as a form of growth. This is done through a fungi cell developing a bud on the parent cell. The parent cell then replicates its DNA and provides the daughter cell with this DNA. The daughter cell is then able to detach itself from the parent cell resulting in multiplication of the fungus. Spores are another mechanism that is utilised as a method of reproduction; the spores act like seeds in that they will flourish when environmental conditions are appropriate and begin to grow hyphae – root like filaments.
context_section_description: Reproduction refers to the process in which an offspring is formed via asexual reproduction or sexual reproduction. Asexual reproduction involves one parent, producing a genetically identical offspring, to the parent cell. Whereas sexual reproduction involves the meeting and fertilisation of gamete cells in order to produce a genetically different offspring. Fungi type organisms reproduce asexually through the release of diploid spores. Spores are micro unicellular cells that are released and dispersed into the environment in a mass of numbers to increase the likelihood of further development and growth of the fungus. As spores are very small in size, they are easily moved via environmental conditions, that being wind, water, or even on an animal’s fur. These spores will find favourable conditions and successfully flourish, develop and grow into the structure and body of the fungi.
  Development of the fungus via spores is initiated through germination; this marks the beginning of fungal development. Spores will begin to develop filaments called hyphae; these are root like structures of the fungi as they branch out into the environment absorbing any available water and other nutrients required for survival. Groups of hyphae will interconnect, forming the main fungal body, the mycelium. The fungi will soon develop a sporangiophore, this is the stalk/stem of the fungus. The sporangiophore is an elongated structure that provides support to the body of the fungus and creates spores. This is done through a process in which the haploid nucleus – a nucleus with half the number of chromosomes for that species – is encased in an outer membrane with a cytoplasm. The haploid nucleus within the sporangiophore fuses with the cytoplasm to create diploid nuclei (spores) – a nucleus with the normal number of chromosomes for a specific species -. These spores then travel through the sporangiophore where they reach the sporangium. The sporangium is the structure within the fungi that is reliant on storing spores. The rupturing of the sporangium releases a large mass of spores into the environment, this enable the fungi to reproduce rapidly.
  Fungal species are also able to reproduce asexually via budding. Budding refers to the process in which an offspring is formed from a parent cell. This occurs for Entomophthora cells already within a host. When environmental conditions are favourable, a fungus cell develops a small growth on the cell body, this is referred to as the bud. The bud will enlarge over time, utilising the nutrients from the parent cell, which in turn ultimately causes growth. The parent cell replicates its DNA through the process of DNA replication – a process in which DNA undergoes a number of steps to formulate a copy of itself during cell division, creating genetically identical DNA to the parent cell-. Once the DNA is replicated within the nucleus, the nucleus then divides. One copy of the nucleus moves into the bud, and the other nucleus remains in the parent cell. When the daughter cell (bud) reaches a certain size, it detaches from the parent cell via cytokinesis. Cytokinesis refers to a process in which the cytoplasm within a cell splits, separating two cells. During budding cytokinesis occurs to separate the daughter cell from the parent cell. Once the daughter cell is detached from the parent cell, it will grow and mature into a large cell and will be able to develop its own bud and hence reproduce.
caption: The process of Fungal Reproduction
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