Flagellar roots, mating structure and gametic fusion in the green alga Ulva lactuca (Ulvales)

1980 ◽  
Vol 46 (1) ◽  
pp. 149-169
Author(s):  
M. Melkonian
Keyword(s):  
Boundary Layer ◽  
Cell Fusion ◽  
Green Algae ◽  
Ulva Lactuca ◽  
Ultrastructural Changes ◽  
Flagellar Roots ◽  
Mating Structure ◽  
Male Gametes ◽  
Microtubular Root ◽  
Microtubular Roots

The slightly anisogamous gametes of Ulva lactuca exhibit a cruciate flagellar root system consisting of 4 microtubular roots (4-2-4-2 system) and an elaborate system of fibrous roots associated with the 2-stranded microtubular roots. Two fibres (32-nm striation periodicity; system I fibres) closely underlie each of the 2-stranded roots, while different fibres (150-nm striation periodicity; system II fibres) run parallel to the root microtubules, and are 150–200 nm more internally located. Female gametes have 4 system II fibres, 3 of which are combined into a compound fibre associated with one microtubular root, while the fourth fibre is associated with the opposite root. In male gametes only 2 system II fibres are present, each underlying one of the two 2-stranded roots. A special region of the plasmalemma of both gamete types about 0.5 mum away from the basal bodies and located between 2 adjacent microtubular roots is structurally specialized and acts as a mating structure in gametic fusion. The region is oval-shaped and up to I.I mum long with a maximum diameter of 0.7 mum. A continuous electron-dense boundary layer underlies the plasmalemma at the edges of the mating structure. In both gamete types the mating structure consists of a fuzzy layer of material underlying the plasmalemma and special granules (60 nm diameter) are associated with this layer on its cytoplasmic side. In addition diffuse material overlies the mating structure, especially in male gametes. The mating structure is connected to 3 different kinds of flagellar roots: the boundary layer is linked to a 2-stranded microtubular root and its associated system I fibre; the fuzzy layer of the mating structure is connected with a system II fibre; and in female gametes this is the compound system II fibre. The ultrastructural changes which occur after mixing the 2 gamete types have been followed. Mating structure activation involves contraction of system II fibres (change of striation periodicity to 100 nm), detachment of special granules from the fuzzy layer of the mating structure and their replacement by electron-transparent vesicles at the prospective cell fusion site. Furthermore, release of electron-dense contents from Golgi-derived vesicles in the anterior part of both gamete types precedes cell fusion. Cell fusion is exclusively initiated in a region delimited by the 2 mating structures. After partial dissolution the 2 plasma membranes unite within the mating structure regions. The ultrastructure of gametic fusion in Ulva lactuca is compared to that of other green algae and the significance of flagellar roots in the mating process of green algae is discussed.

Ultrastructure of the flagellar roots in Chlamydomonas gametes

1984 ◽  
Vol 67 (1) ◽  
pp. 133-143
Author(s):  
R.L. Weiss
Keyword(s):  
Basal Body ◽  
Direct Contact ◽  
The Other ◽  
Basal Bodies ◽  
Flagellar Roots ◽  
Mating Structure ◽  
Membrane Extension ◽  
Microtubular Root ◽  
Basal Apparatus ◽  
Microtubular System

The cytoskeleton of Chlamydomonas reinhardtii gametes has been studied by electron microscopy. The microtubular system, consisting of four flagellar roots inserted into the basal apparatus, is shown to include two daughter basal bodies and two striated fibres, newly described in this report. One new fibre associates with the 3-over-1 root and is similar to its counterpart, the striated fibre of the 2-member root. These similar root fibres connect each daughter basal body to the V-shaped microtubular root pair. The other new striated fibre joins the daughter basal body to both flagellar roots and is similar to the proximal striated fibre. In mt+ gametes, the conventional root microtubules make direct contact with the doublet zone of the non-activated mating structure. During activation, doublet zone microfilaments associate with the daughter basal body and the finely striated fibre of the 3-over-1 root. These observations suggest that the cytoskeleton acts as a scaffolding for membrane extension by the mt+ mating structure microfilaments.

Wastewater Treatment Using Marine Algae Biomass as Pollutants Removal

2018 ◽  
Vol 69 (5) ◽  
pp. 1089-1098
Author(s):  
Elena Suzana Biris Dorhoi ◽  
Maria Tofana ◽  
Simona Maria Chis ◽  
Carmen Elena Lupu ◽  
Ticuta Negreanu Pirjol
Keyword(s):  
Wastewater Treatment ◽  
Green Algae ◽  
Marine Algae ◽  
Tap Water ◽  
Ulva Lactuca ◽  
Raw Material ◽  
Bioactive Substances ◽  
Algae Biomass ◽  
Marine Biomass ◽  
Pollutants Removal

The valorification of the marine biomass is an important resource for many industries like pharmaceutical, supplying raw material for the extraction of bioactive substances (vitamins, sterols and collagen), cosmetics, biofertilizers and wastewater treatment. In the last years a special attention has been given to the use of macroalgae. The aim of this study was to emphasize the capacity of two representative green algae species frequent presents on the Romanian shore, Ulva lactuca (L.) and Cladophora vagabunda (L.) Hoek, to remove two usual detergents from wastewater. The green algae washed, dried at room temperature, macerated to powder were introduced into different filter paper for comparison, then immersed in waste water treated with different concentrations of detergents. Tap water was used for the experiment. The results show that Ulva lactuca (L.) species is suitable than Cladophora vagabunda (L.) Hoek species, for wastewater treatment.

scholarly journals The Chlamydomonas Mating Type Plus Fertilization Tubule, a Prototypic Cell Fusion Organelle: Isolation, Characterization, and In Vitro Adhesion to Mating Type Minus Gametes

1997 ◽  
Vol 137 (7) ◽  
pp. 1537-1553 ◽  
Author(s):  
Nedra F. Wilson ◽  
Mary J. Foglesong ◽  
William J. Snell
Keyword(s):  
Cell Fusion ◽  
Mating Type ◽  
Plasma Membranes ◽  
Surface Proteins ◽  
Filamentous Actin ◽  
Mating Structure ◽  
Cell Protrusion ◽  
Isolation And Characterization ◽  
In Vitro Adhesion

In the biflagellated alga Chlamydomonas, adhesion and fusion of the plasma membranes of gametes during fertilization occurs via an actin-filled, microvillus-like cell protrusion. Formation of this ∼3-μm-long fusion organelle, the Chlamydomonas fertilization tubule, is induced in mating type plus (mt+) gametes during flagellar adhesion with mating type minus (mt−) gametes. Subsequent adhesion between the tip of the mt+ fertilization tubule and the apex of a mating structure on mt− gametes is followed rapidly by fusion of the plasma membranes and zygote formation. In this report, we describe the isolation and characterization of fertilization tubules from mt+ gametes activated for cell fusion. Fertilization tubules were detached by homogenization of activated mt+ gametes in an EGTA-containing buffer and purified by differential centrifugation followed by fractionation on sucrose and Percoll gradients. As determined by fluorescence microscopy of samples stained with a fluorescent probe for filamentous actin, the method yielded 2–3 × 106 fertilization tubules/μg protein, representing up to a 360-fold enrichment of these organelles. Examination by negative stain electron microscopy demonstrated that the purified fertilization tubules were morphologically indistinguishable from fertilization tubules on intact, activated mt+ gametes, retaining both the extracellular fringe and the internal array of actin filaments. Several proteins, including actin as well as two surface proteins identified by biotinylation studies, copurified with the fertilization tubules. Most importantly, the isolated mt+ fertilization tubules bound to the apical ends of activated mt− gametes between the two flagella, the site of the mt− mating structure; a single fertilization tubule bound per cell, binding was specific for gametes, and fertilization tubules isolated from trypsin-treated, activated mt+ gametes did not bind to activated mt− gametes.

scholarly journals Interrelationships between microtubules, a striated fiber, and the gametic mating structure of Chlamydomonas reinhardi.

1978 ◽  
Vol 76 (2) ◽  
pp. 430-438 ◽  
Author(s):  
U W Goodenough ◽  
R L Weiss
Keyword(s):  
Flagellar Apparatus ◽  
Flagellar Roots ◽  
Mating Structure ◽  
Striated Fiber

The microtubule system associated with the Chlamydomonas reinhardi flagellar apparatus is shown to differ from previous descriptions; two of the four flagellar "roots" possess only two microtubules and are associated with a finely striated fiber. In gametic cells this fiber underlies the gametic mating structure and makes contact with it. Functional interpretations are offered.

scholarly journals In vitro and in vivo antimicrobial activity of Ulva lactuca Linn. (Green algae) associated endophytic bacterial Strains

2016 ◽  
pp. 138-146 ◽  
Author(s):  
Prasanna Habbu ◽  
Vijayanand Warad ◽  
Rajesh Shastri ◽  
Chetan Savant ◽  
Smita Madagundi ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Green Algae ◽  
Ulva Lactuca ◽  
Bacterial Strains

scholarly journals Gastroprotective Effect of Green Algae Extract (Ulva lactuca L) on Gastric Rats

2020 ◽  
Vol 7 (2) ◽  
pp. 73
Author(s):  
Wahyu Widyaningsih ◽  
Siti Nurasih Afdaliah
Keyword(s):  
Gastric Ulcer ◽  
Green Algae ◽  
Negative Control ◽  
Ulva Lactuca ◽  
P Value ◽  
Ulcer Index ◽  
Gastroprotective Effect ◽  
Group I ◽  
Significant Difference ◽  
Protection Ratio

Gastric ulcer is a disease of the digestive tract characterized by mucous damage to secretion of gastric acid and pepsin. One of the potential gastroprotector plants is green algae. The purpose of this study was to examine the gastroprotective effect of ethanol extract of green algae (EEGH) Ulva lactuca L on the gastric of ethanol-induced rats. This study used 36 rats, divided into 6 groups. Group I is a normal group. Group II negative control, ethanol 96% induced. Group III positive control, given comparison of ranitidine dose of 15.75 mg/kgBW. Groups IV, V and VI were given multilevel EEGH, namely 125, 250 and 500 mg/kgBW. The treatment was carried out for 14 days, on the 14th day ethanol 96% was induced and then dissected. Research data on gastric ulcer index and protection ratio were analyzed using One Way ANOVA with a confidence level of 95%. The results of the EEGH statistical test dose of 500 mg/kgBW with negative controls showed a significant difference with p value of 0.013 (p<0.05). The EEGH 500 mg/kgBW has the ability as an effective gastroprotector, as seen from the gastric ulcer index value of 0.5 and the protection ratio of 78.94%.Keywords: Ethanol, gastroprotector, protection ratio, ulcer index, Ulva lactuca L.78,94%. 

scholarly journals ISOLATION AND GENETIC ANALYSIS OF MUTANT STRAINS OF CHLAMYDOMONAS REINHARDI DEFECTIVE IN GAMETIC DIFFERENTIATION

Genetics ◽  
1976 ◽  
Vol 82 (2) ◽  
pp. 169-186
Author(s):  
Ursula W Goodenough ◽  
Carol Hwang ◽  
Howard Martin
Keyword(s):  
Genetic Analysis ◽  
Cell Fusion ◽  
Mating Type ◽  
Normal Growth ◽  
The Other ◽  
Genetic Dissection ◽  
Structural Studies ◽  
Tetrad Analysis ◽  
Mating Structure ◽  
Mutant Strains

ABSTRACT Impotent mutant strains of Chlamydomonas reinhardi, mating-type (mt) plus, are described that have normal growth and motility but fail to differentiate into normal gametes. Procedures for their isolation and their genetic analysis are described. Five of the imp strains (imp-2, imp-5, imp-6, imp-7, and imp-8) exhibit no flagellar agglutination when mixed with mt  - or mt  + gametes; these strains have been induced to form rare zygotes with mt  - gametes and the mutations are shown to be unlinked to the mt locus (with the possible exception of imp-7). Two of the strains (imp-3 and imp-4) carry leaky mutations that affect cell fusion; neither mutation is found by tetrad analysis to be linked to mt or to the other. Cells of the imp-1 strain agglutinate well with mt  - gametes and active agglutination continues for up to 48 hours, but cell fusion occurs only very rarely. Analysis of these rare zygotes indicates that imp-1 is closely linked to the mt  + locus, and fine-structural studies reveal that imp-1gametes produce a mutant mating structure involved in zygotic cell fusion. The development of sexuality in C. reinhardi therefore appears amenable to genetic dissection.

scholarly journals A comparative test of the gamete dynamics theory for the evolution of anisogamy in Bryopsidales green algae

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Tatsuya Togashi ◽  
Yusuke Horinouchi ◽  
Geoff A. Parker
Keyword(s):  
Life Cycle ◽  
Green Algae ◽  
Adult Stage ◽  
Male Gamete ◽  
Comparative Test ◽  
Disruptive Selection ◽  
Adult Size ◽  
Male Gametes ◽  
Selection For ◽  
Gamete Size

Gamete dynamics theory proposes that anisogamy arises by disruptive selection for gamete numbers versus gamete size and predicts that female/male gamete size (anisogamy ratio) increases with adult size and complexity. Evidence has been that in volvocine green algae, the anisogamy ratio correlates positively with haploid colony size. However, green algae show notable exceptions. We focus on Bryopsidales green algae. While some taxa have a diplontic life cycle in which a diploid adult (=fully grown) stage arises directly from the zygote, many taxa have a haplodiplontic life cycle in which haploid adults develop indirectly: the zygote first develops into a diploid adult (sporophyte) which later undergoes meiosis and releases zoospores, each growing into a haploid adult gametophyte. Our comparative analyses suggest that, as theory predicts: (i) male gametes are minimized, (ii) female gamete sizes vary, probably optimized by number versus survival as zygotes, and (iii) the anisogamy ratio correlates positively with diploid (but not haploid) stage complexity. However, there was no correlation between the anisogamy ratio and diploid adult stage size. Increased environmental severity (water depth) appears to drive increased diploid adult stage complexity and anisogamy ratio: gamete dynamics theory correctly predicts that anisogamy evolves with the (diploid) stage directly provisioned by the zygote.

scholarly journals Ulva lactuca, A Source of Troubles and Potential Riches

Marine Drugs ◽  
2019 ◽  
Vol 17 (6) ◽  
pp. 357 ◽  
Author(s):  
Herminia Dominguez ◽  
Erwann P. Loret
Keyword(s):  
Green Algae ◽  
Bioactive Compounds ◽  
Human Activities ◽  
Ulva Lactuca ◽  
Water Salinity ◽  
Shallow Waters ◽  
Green Tides ◽  
Genetic Analyses ◽  
Valuable Compounds ◽  
Environment Parameters

Ulva lactuca is a green macro alga involved in devastating green tides observed worldwide. These green tides or blooms are a consequence of human activities. Ulva blooms occur mainly in shallow waters and the decomposition of this alga can produce dangerous vapors. Ulva lactuca is a species usually resembling lettuce, but genetic analyses demonstrated that other green algae with tubular phenotypes were U. lactuca clades although previously described as different species or even genera. The capacity for U. lactuca to adopt different phenotypes can be due to environment parameters, such as the degree of water salinity or symbiosis with bacteria. No efficient ways have been discovered to control these green tides, but the Mediterranean seas appear to be protected from blooms, which disappear rapidly in springtime. Ulva contains commercially valuable components, such as bioactive compounds, food or biofuel. The biomass due to this alga collected on beaches every year is beginning to be valorized to produce valuable compounds. This review describes different processes and strategies developed to extract these different valuable components.

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