Cell-wall abnormalities of a Chlamydomonas reinhardtii mutant strain under suboptimal growth conditions

Planta ◽  
1991 ◽  
Vol 183 (1) ◽  
Author(s):  
J�rgen Voigt ◽  
Dieter Mergenhagen ◽  
Irmhild Wachholz ◽  
Elsbeth Manshard ◽  
Marianne Mix
Keyword(s):  
Cell Wall ◽  
Chlamydomonas Reinhardtii ◽  
Mutant Strain ◽  
Growth Conditions

scholarly journals BALD-2: a mutation affecting the formation of doublet and triplet sets of microtubules in Chlamydomonas reinhardtii.

1975 ◽  
Vol 66 (3) ◽  
pp. 480-491 ◽  
Author(s):  
U W Goodenough ◽  
H S StClair
Keyword(s):  
Cell Wall ◽  
Chlamydomonas Reinhardtii ◽  
Transition Region ◽  
Structural Stability ◽  
Mutant Strain ◽  
Basal Body ◽  
Fiber Material ◽  
Basal Bodies ◽  
Critical Properties ◽  
Striated Fiber

The mutant strain bald-2 is unique among "flagellaless" strains of Chlamydomonas reinhardtii isolated to date, in that it possesses a mutant basal body: it is only capable of forming a ring of nine singlet microtubules, 180 nm in diameter, instead of the usual triplet basal body which is 225 nm in diameter. This singlet basal body lacks structural stability and the ability to associate with striated fiber material but retains two critical properties of basal bodies, namely, information specifying the length to which it should elongate and the ability to induce, albeit rarely, a flagellar transition region, a short, singlet-containing axoneme, and a specialized tunnel in the cell wall through which flagella normally emerge. The mutation seems to be specific for B- and C-microtubule synthesis or assembly since all other cytoplasmic sets of microtubules appear normal in numbers, orientation, and stability.

scholarly journals A Metzincin and TIMP-Like Protein Pair of a Phage Origin Sensitize Listeria monocytogenes to Phage Lysins and Other Cell Wall Targeting Agents

2021 ◽  
Vol 9 (6) ◽  
pp. 1323
Author(s):  
Etai Boichis ◽  
Nadejda Sigal ◽  
Ilya Borovok ◽  
Anat A. Herskovits
Keyword(s):  
Cell Wall ◽  
Listeria Monocytogenes ◽  
Mammalian Cells ◽  
Protein Pair ◽  
Growth Conditions ◽  
Wall Structure ◽  
Antibiotic Resistant ◽  
Extracellular Milieu ◽  
Virion Release ◽  
Genes Encoding

Infection of mammalian cells by Listeria monocytogenes (Lm) was shown to be facilitated by its phage elements. In a search for additional phage remnants that play a role in Lm’s lifecycle, we identified a conserved locus containing two XRE regulators and a pair of genes encoding a secreted metzincin protease and a lipoprotein structurally similar to a TIMP-family metzincin inhibitor. We found that the XRE regulators act as a classic CI/Cro regulatory switch that regulates the expression of the metzincin and TIMP-like genes under intracellular growth conditions. We established that when these genes are expressed, their products alter Lm morphology and increase its sensitivity to phage mediated lysis, thereby enhancing virion release. Expression of these proteins also sensitized the bacteria to cell wall targeting compounds, implying that they modulate the cell wall structure. Our data indicate that these effects are mediated by the cleavage of the TIMP-like protein by the metzincin, and its subsequent release to the extracellular milieu. While the importance of this locus to Lm pathogenicity remains unclear, the observation that this phage-associated protein pair act upon the bacterial cell wall may hold promise in the field of antibiotic potentiation to combat antibiotic resistant bacterial pathogens.

Linkage group XIX of Chlamydomonas reinhardtii has a linear map.

Genetics ◽  
1993 ◽  
Vol 133 (4) ◽  
pp. 865-874
Author(s):  
J A Holmes ◽  
D E Johnson ◽  
S K Dutcher
Keyword(s):  
Linkage Group ◽  
Chlamydomonas Reinhardtii ◽  
Mutant Strain ◽  
Meiotic Recombination ◽  
Temperature Sensitive ◽  
Unusual Property ◽  
Linkage Groups ◽  
Excess Number ◽  
Chiasma Interference ◽  
Double Crossovers

Abstract Linkage group XIX (or the UNI linkage group) of Chlamydomonas reinhardtii has been reported to show a circular meiotic recombination map. A circular map predicts the existence of strong chiasma and chromatid interference, which would lead to an excess number of two-strand double crossovers during meiosis. We have tested this prediction in multipoint crosses. Our results are consistent with a linear linkage group that shows positive chiasma interference and no chromatid interference. Chiasma interference occurs both within arms and across the centromere. Of the original loci that contributed to the circular map, we find that two map to other linkage groups and a third cannot be retested because the mutant strain that defined it has been lost. A second reported unusual property for linkage group XIX was the increase in meiotic recombination with increases in temperature during a period that precedes the onset of meiosis. Although we observed changes in recombination frequencies in some intervals on linkage group XIX in crosses to CC-1952, and in strains heterozygous for the mutation ger1 at 16 degrees, we also show that our strains do not exhibit the previously observed patterns of temperature-sensitive recombination for two different pairs of loci on linkage group XIX. We conclude that linkage group XIX has a linear genetic map that is not significantly different from other Chlamydomonas linkage groups.

A Simple Method for Removal of the Chlamydomonas reinhardtii Cell Wall Using a Commercially Available Subtilisin (Alcalase)

2018 ◽  
Vol 28 (4) ◽  
pp. 169-178 ◽  
Author(s):  
Hyun-Ju Hwang ◽  
Yong Tae Kim ◽  
Nam Seon Kang ◽  
Jong Won Han
Keyword(s):  
Cell Wall ◽  
Chlamydomonas Reinhardtii ◽  
Algal Cell ◽  
Chemical Properties ◽  
Transformation Method ◽  
Lytic Enzyme ◽  
Higher Plant ◽  
Time Saving ◽  
Simple Method ◽  
Cell Wall Disruption

The algal cell wall is a potent barrier for delivery of transgenes for genetic engineering. Conventional methods developed for higher plant systems are often unable to penetrate or remove algal cell walls owing to their unique physical and chemical properties. Therefore, we developed a simple transformation method for <i>Chlamydomonas reinhardtii</i> using commercially available enzymes. Out of 7 enzymes screened for cell wall disruption, a commercial form of subtilisin (Alcalase) was the most effective at a low concentration (0.3 Anson units/mL). The efficiency was comparable to that of gamete lytic enzyme, a protease commonly used for the genetic transformation of <i>C. reinhardtii</i>. The transformation efficiency of our noninvasive method was similar to that of previous methods using autolysin as a cell wall-degrading enzyme in conjunction with glass bead transformation. Subtilisin showed approximately 35% sequence identity with sporangin, a hatching enzyme of <i>C. reinhardtii</i>, and shared conserved active domains, which may explain the effective cell wall degradation. Our trans­formation method using commercial subtilisin is more reliable and time saving than the conventional method using autolysin released from gametes for cell wall lysis.

scholarly journals Nutritionally variant streptococci.

1991 ◽  
Vol 4 (2) ◽  
pp. 184-190 ◽  
Author(s):  
K L Ruoff
Keyword(s):  
Cell Wall ◽  
Oral Cavity ◽  
Successful Treatment ◽  
Distinct Species ◽  
Growth Conditions ◽  
Clinical Specimens ◽  
Wide Range ◽  
Streptococcal Species ◽  
A Cell

Streptococci requiring either pyridoxal or L-cysteine for growth were first observed 30 years ago as organisms forming satellite colonies adjacent to colonies of "helper" bacteria. Although they were previously considered nutritional mutants of viridans streptococcal species, the nutritionally variant streptococci (NVS) are currently thought to belong to distinct species of the genus Streptococcus. NVS strains may display pleomorphic cellular morphologies, depending on their growth conditions, and are distinguished from most other streptococci by enzymatic and serological characteristics and the presence of a cell wall chromophore. NVS are found as normal inhabitants of the oral cavity, and in addition to their participation in endocarditis, they have been isolated from a wide range of clinical specimens. Endocarditis caused by NVS is often difficult to eradicate; combinations of penicillin and an aminoglycoside are recommended for treatment. The unique physiological features of the NVS contribute to the difficulties encountered in their recovery from clinical specimens and may play a role in the problems associated with successful treatment of NVS endocarditis.

scholarly journals Role of BGS13 in the Secretory Mechanism of Pichia pastoris

2019 ◽  
Vol 85 (24) ◽  
Author(s):  
Christopher A. Naranjo ◽  
Anita D. Jivan ◽  
Maria N. Vo ◽  
Katherine H. de Sa Campos ◽  
Jared S. Deyarmin ◽  
...  
Keyword(s):  
Cell Wall ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Pichia Pastoris ◽  
Mutant Strain ◽  
Recombinant Proteins ◽  
Economic Benefits ◽  
Heterologous Protein Expression ◽  
Content Type ◽  
Kinase C

ABSTRACT The methylotrophic yeast Pichia pastoris has been utilized for heterologous protein expression for over 30 years. Because P. pastoris secretes few of its own proteins, the exported recombinant protein is the major polypeptide in the extracellular medium, making purification relatively easy. Unfortunately, some recombinant proteins intended for secretion are retained within the cell. A mutant strain isolated in our laboratory, containing a disruption of the BGS13 gene, displayed elevated levels of secretion for a variety of reporter proteins. The Bgs13 peptide (Bgs13p) is similar to the Saccharomyces cerevisiae protein kinase C 1 protein (Pkc1p), but its specific mode of action is currently unclear. To illuminate differences in the secretion mechanism between the wild-type (wt) strain and the bgs13 strain, we determined that the disrupted bgs13 gene expressed a truncated protein that had reduced protein kinase C activity and a different location in the cell, compared to the wt protein. Because the Pkc1p of baker’s yeast plays a significant role in cell wall integrity, we investigated the sensitivity of the mutant strain’s cell wall to growth antagonists and extraction by dithiothreitol, determining that the bgs13 strain cell wall suffered from inherent structural problems although its porosity was normal. A proteomic investigation of the bgs13 strain secretome and cell wall-extracted peptides demonstrated that, compared to its wt parent, the bgs13 strain also displayed increased release of an array of normally secreted, endogenous proteins, as well as endoplasmic reticulum-resident chaperone proteins, suggesting that Bgs13p helps regulate the unfolded protein response and protein sorting on a global scale. IMPORTANCE The yeast Pichia pastoris is used as a host system for the expression of recombinant proteins. Many of these products, including antibodies, vaccine antigens, and therapeutic proteins such as insulin, are currently on the market or in late stages of development. However, one major weakness is that sometimes these proteins are not secreted from the yeast cell efficiently, which impedes and raises the cost of purification of these vital proteins. Our laboratory has isolated a mutant strain of Pichia pastoris that shows enhanced secretion of many proteins. The mutant produces a modified version of Bgs13p. Our goal is to understand how the change in the Bgs13p function leads to improved secretion. Once the Bgs13p mechanism is illuminated, we should be able to apply this understanding to engineer new P. pastoris strains that efficiently produce and secrete life-saving recombinant proteins, providing medical and economic benefits.

scholarly journals Chlamydomonas reinhardtii Has Multiple Prolyl 4-Hydroxylases, One of Which Is Essential for Proper Cell Wall Assembly

2007 ◽  
Vol 19 (1) ◽  
pp. 256-269 ◽  
Author(s):  
Katriina Keskiaho ◽  
Reija Hieta ◽  
Raija Sormunen ◽  
Johanna Myllyharju
Keyword(s):  
Cell Wall ◽  
Chlamydomonas Reinhardtii ◽  
Cell Wall Assembly ◽  
Wall Assembly
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