The intracellular reserve polysaccharide of Clostridium pasteurianum

1977 ◽  
Vol 23 (8) ◽  
pp. 947-953 ◽  
Author(s):  
A. G. Darvill ◽  
M. A. Hall ◽  
J. P. Fish ◽  
J. G. Morris
Keyword(s):  
Mutant Strain ◽  
Minimal Medium ◽  
Clostridium Pasteurianum ◽  
Wild Type ◽  
Methylation Analysis ◽  
Glucose Content ◽  
Glucose Minimal Medium ◽  
Intracellular Polysaccharide ◽  
Type Strains ◽  
Negative Mutant

An amylopectinlike polysaccharide (granulose) was the only glucan produced in significant quantities by six wild-type strains of Clostridium pasteurianum grown in glucose minimal medium. The intracellular polysaccharide granules laid down before sporulation contained only this amylopectin. No intracellular dextran was discovered in these wild-type strains, nor in a granulose-negative mutant strain of C. pasteurianum possessing an ADP glucose pyrophosphorylase (EC 2.7.7.27) but lacking a granulose synthase (i.e. ADPglucose-α-1,4-glucan glucosyl transferase, EC 2.4.1.21). Furthermore, methylation analysis demonstrated that (1 → 6) linked α-D-glucose units accounted for less than 2% of the entire glucose content of these organisms.

A visual indicator of heterokaryosis in Fusarium oxysporum from celery

1984 ◽  
Vol 62 (3) ◽  
pp. 540-545 ◽  
Author(s):  
John E. Puhalla
Keyword(s):  
Fusarium Oxysporum ◽  
Ultraviolet Light ◽  
Minimal Medium ◽  
Genetic Complementation ◽  
Wild Type ◽  
Uv Treatment ◽  
Formae Speciales ◽  
Auxotrophic Mutants ◽  
Pale Pink ◽  
Type Strains

Wild-type isolates of Fusarium oxysporum f. sp. apii (celery pathogens) were white or pale pink. Ultraviolet-light (UV) treatment of conidia, however, yielded stable orange mutants, which in turn gave rise to yellow and white mutants after a second UV treatment. Some pairings between these yellow and white mutants developed an orange line where they touched. This orange line developed only if the two mutants formed heterokaryons with each other. In contrast, attempts to demonstrate heterokaryons between complementary auxotrophic mutants on minimal medium failed. The color heterokaryon was a mosaic of homokaryotic and heterokaryotic cells, the latter being confined to the area of anastomosis between the two mutants. Genetic complementation was also confined to this area. In pairings among color mutants of five wild-type strains two vegetative (heterokaryon) compatibility (VC) groups were defined. VC groups in other formae spéciales of F. oxysporum should also be detectable by this method.

scholarly journals CHLOROPLAST STRUCTURE AND FUNCTION IN ac-20, A MUTANT STRAIN OF CHLAMYDOMONAS REINHARDI

1970 ◽  
Vol 44 (3) ◽  
pp. 547-562 ◽  
Author(s):  
Ursula W. Goodenough ◽  
R. P. Levine
Keyword(s):  
Mutant Strain ◽  
Minimal Medium ◽  
Structure And Function ◽  
Membrane Organization ◽  
Chloroplast Structure ◽  
Wild Type ◽  
Fold Reduction ◽  
Membrane Reorganization ◽  
And Function ◽  
Photosynthetic Properties

The fine structure of the ac-20 strain of Chlamydomonas reinhardi is described. Cells grown mixotrophically in the presence of acetate have a highly disordered chloroplast membrane organization and usually lack pyrenoids. Chloroplast ribosome levels are only 5–10% of wild-type levels. Cells grown phototrophically without acetate possess more chloroplast ribosomes and have more normal membrane and pyrenoid organization. Chloroplast ribosome levels rise rapidly when cells are transferred from acetate to minimal medium, whereas membrane reorganization occurs only after a lag. These results, combined with earlier studies of the photosynthetic properties of the mutant strain, suggest that proper membrane organization, Photosystem II activity, and ribulose-1,5-diphosphate carboxylase formation are dependent on the presence of chloroplast ribosomes. Other chloroplast components tested are unaffected by a 10-fold reduction in levels of chloroplast ribosomes.

scholarly journals SELECTIVE ABORTION OF TWO NONSISTER NUCLEI IN A DEVELOPING ASCUS OF THE hfd1—1 MUTANT IN SACCHAROMYCES CEREVISIAE

Genetics ◽  
1981 ◽  
Vol 99 (2) ◽  
pp. 197-209
Author(s):  
Susumu Okamoto ◽  
Tetsuo Iino
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mutant Strain ◽  
Recessive Mutation ◽  
Microscopical Examination ◽  
Wild Type ◽  
Selective Abortion ◽  
Dyad Analysis ◽  
Mutant Cells ◽  
Type Strains ◽  
Light Microscopical Examination

ABSTRACT A recessive mutation, hfd1—1, in strain SOS4 of Saccharomyces cerevisiae leads the mutant cells to produce predominantly two-spored asci. Light microscopical examination of Giemsastained cells revealed no significant differences in the meiotic figures between mutant and wild-type strains. However, only two of the four meiotic products in a developing ascus matured to ascospores in SOS4. Dyad analysis was carried out on an hfd1-1 mutant strain heterozygous for three markers, asp5, gal1 and arg4, which are closely linked to their centromeres, and for his4, which is loosely linked to its centromere. The twospored asci produced by the hfd1—1 mutant segregated dominant (+) and recessive (-) alleles of each marker in a 1:1 ratio; they generally contained one + and one - spore for any given marker. The occurrence of rare dyads with two + or two - spores can be explained quantitatively by recombination between the marker and its centromere. From the results of these cytological and genetical analyses, we infer that, in the mutant strain, one genome set is partitioned to each of the four second-meiotic division poles, but only two nonsister genomes are incorporated into mature spores. Thus, the hfd1—1 mutation in SOS4 blocks incorporation of two nonsister nuclei into mature ascospores, but does not block enclosure of the remaining two nonsister nuclei.

scholarly journals HpaA Is Essential for Helicobacter pylori Colonization in Mice

2006 ◽  
Vol 74 (2) ◽  
pp. 920-926 ◽  
Author(s):  
Elisabet Carlsohn ◽  
Johanna Nyström ◽  
Ingrid Bölin ◽  
Carol L. Nilsson ◽  
Ann-Mari Svennerholm
Keyword(s):  
Helicobacter Pylori ◽  
Mutant Strain ◽  
Protein Profile ◽  
Expression Patterns ◽  
Protein Profiling ◽  
In Vivo Studies ◽  
Wild Type ◽  
Cell Extracts ◽  
H Pylori ◽  
Type Strains

ABSTRACT Infection with the human gastric pathogen Helicobacter pylori can give rise to chronic gastritis, peptic ulcer, and gastric cancer. All H. pylori strains express the surface-localized protein HpaA, a promising candidate for a vaccine against H. pylori infection. To study the physiological importance of HpaA, a mutation of the hpaA gene was introduced into a mouse-adapted H. pylori strain. To justify that the interruption of the hpaA gene did not cause any polar effects of downstream genes or was associated with a second site mutation, the protein expression patterns of the mutant and wild-type strains were characterized by two different proteomic approaches. Two-dimensional differential in-gel electrophoresis analysis of whole-cell extracts and subcellular fractionation combined with nano-liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry for outer membrane protein profiling revealed only minor differences in the protein profile between the mutant and the wild-type strains. Therefore, the mutant strain was tested for its colonizing ability in a well-established mouse model. While inoculation with the wild-type strain resulted in heavily H. pylori-infected mice, the HpaA mutant strain was not able to establish colonization. Thus, by combining proteomic analysis and in vivo studies, we conclude that HpaA is essential for the colonization of H. pylori in mice.

scholarly journals Chromosomal Amplification of the Escherichia coli lipB Region Confers High-Level Resistance to Selenolipoic Acid

2002 ◽  
Vol 184 (19) ◽  
pp. 5495-5501 ◽  
Author(s):  
Sean W. Jordan ◽  
John E. Cronan,
Keyword(s):  
Escherichia Coli ◽  
Mutant Strain ◽  
Minimal Medium ◽  
Chromosomal Region ◽  
Null Mutation ◽  
Wild Type ◽  
High Level ◽  
Level Resistance

ABSTRACT One of the mutants (slr7 mutant) of a wild-type Escherichia coli strain resistant to selenolipoic acid reported previously (K. E. Reed, T. W. Morris, and J. E. Cronan, Jr., Proc. Natl. Acad. Sci. USA 91:3720-3724, 1994) unexpectedly grew on minimal medium following transductional introduction of a lipA null mutation. We report that the slr7 strain carries a duplication of the lip chromosomal region that causes the phenotype of the mutant strain.

scholarly journals The Inheritance of the Glucose Component of the Phage Nucleic Acids

1961 ◽  
Vol 44 (3) ◽  
pp. 585-603 ◽  
Author(s):  
Margeris A. Jesaitis
Keyword(s):  
Nucleic Acid ◽  
Host Range ◽  
Chemical Properties ◽  
Serial Passage ◽  
The Other ◽  
Wild Type ◽  
Or Efficiency ◽  
Glucose Content ◽  
E Coli ◽  
Type Strains

The wild type strains of T2 and T6 bacteriophages differ in their host range specificity, efficiency of plating on E. coli K12, and in glucose content. A study of the inheritance of these three differentiating characteristics has revealed that they are transmitted both upon serial passage of the viruses and when the two phages are crossed. It has been found, furthermore, that an extensive recombination takes place upon crossing. Four types of hybrid phages have been isolated from the progeny of crosses, which had a glucose content of one of the parental phages, and either the host range specificity or efficiency of plating or both of the other. The characteristics of each hybrid were found to be hereditarily stable. It has been concluded that the transmission of the characteristics under consideration is determined genetically and that the genes which control them are not closely linked. Since the glucose content of a phage is determined by the degree of glucosylation of its nucleic acid, the T2 and T6 phages apparently contain genes which control certain chemical properties of their nucleic acid.

Construction of an Escherichia coli strain which excretes abnormally large amounts of adenosine 3′,5′-cyclic monophosphate

1978 ◽  
Vol 24 (11) ◽  
pp. 1423-1425 ◽  
Author(s):  
Ann D. E. Fraser ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Minimal Medium ◽  
Coli Strain ◽  
Coli Cell ◽  
Wild Type ◽  
Camp Phosphodiesterase ◽  
E Coli ◽  
Cyclic Monophosphate ◽  
Glucose Minimal Medium ◽  
P1 Transduction

It has previously been shown that an Escherichia coli CRP− strain 5333 accumulates abnormally large amounts of adenosine 3′,5′-cyclic monophosphate (cAMP). Using P1 transduction, the CRP− character was transferred to E. coli Crookes strain which is deficient for cAMP phosphodiesterase (CPD−). The resulting strain HY22 (CRP−, CPD−) accumulates greater amounts of cAMP both intracellularly and extracellularly than does 5333. In glucose minimal medium, an HY22 cell accumulates 100 times more cAMP intracellularly and excretes cAMP 150 times faster than does a wild-type E. coli cell.

scholarly journals Role of Group A Streptococcal Virulence Factors in Adherence to Keratinocytes

2000 ◽  
Vol 68 (3) ◽  
pp. 1215-1221 ◽  
Author(s):  
Gary L. Darmstadt ◽  
Laurel Mentele ◽  
Andreas Podbielski ◽  
Craig E. Rubens
Keyword(s):  
Hyaluronic Acid ◽  
Mutant Strain ◽  
Virulence Factors ◽  
M Protein ◽  
Skin Infections ◽  
Wild Type ◽  
Group A ◽  
Hyaluronic Acid Capsule ◽  
Type Strains

ABSTRACT To evaluate the role of putative group A streptococcal virulence factors in the initiation of skin infections, we compared the adherence of a wild-type M49-protein skin-associated strain to that of a series of 16 isogenic mutants created by insertional inactivation of virulence genes. None of the mutants, including the M-protein-deficient (emm mutant) strain, displayed reduced adherence to early-passage cultured human keratinocytes, but adherence of the mutant lacking hyaluronic acid capsule expression (has mutant) was increased 13-fold. In contrast, elimination of capsule expression in M2-, M3-, and M18-protein has mutants increased adherence only slightly (1.3- to 2.3-fold) compared to their respective wild-type strains. A mutant with inactivation of both emm andhas displayed high-level adherence (34.9 ± 4.1%) equal to that of the has mutant strain (40.7 + 8.0%), confirming the lack of involvement of M49 protein in attachment. Moreover, adherence of the M49-protein-deficient (emmmutant) and wild-type strains was increased to the same level (57 and 55%, respectively) following enzymatic digestion of their hyaluronic acid capsule. Adherence of mutants lacking oligopeptide permease (Opp) expression was increased 3.8- to 5.5-fold, in association with decreased cell-associated hyaluronic acid capsule. Finally, soluble CD46 failed to inhibit adherence of M49- and M52-serotype skin strains. We conclude that (i) bacterial M protein and keratinocyte CD46 do not mediate adherence of M49 skin-associated Streptococcus pyogenes to epidermal keratinocytes, (ii) hyaluronic acid capsule impedes the interaction of bacterial adhesins with keratinocyte receptors, (iii) modulation of capsule expression may be important in the pathogenesis of skin infections, and (iv) the molecular interactions in attachment of skin strains of S. pyogenesto keratinocytes are unique and remain unidentified.

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