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Sample records for a53t mutant form

  1. Tauopathic changes in the striatum of A53T α-synuclein mutant mouse model of Parkinson's disease.

    Jonathan Wills

    Full Text Available Tauopathic pathways lead to degenerative changes in Alzheimer's disease and there is evidence that they are also involved in the neurodegenerative pathology of Parkinson's disease [PD]. We have examined tauopathic changes in striatum of the α-synuclein (α-Syn A53T mutant mouse. Elevated levels of α-Syn were observed in striatum of the adult A53T α-Syn mice. This was accompanied by increases in hyperphosphorylated Tau [p-Tau], phosphorylated at Ser202, Ser262 and Ser396/404, which are the same toxic sites also seen in Alzheimer's disease. There was an increase in active p-GSK-3β, hyperphosphorylated at Tyr216, a major and primary kinase known to phosphorylate Tau at multiple sites. The sites of hyperphosphorylation of Tau in the A53T mutant mice were similar to those seen in post-mortem striata from PD patients, attesting to their pathophysiological relevance. Increases in p-Tau were not due to alterations on protein phosphatases in either A53T mice or in human PD, suggesting lack of involvement of these proteins in tauopathy. Extraction of striata with Triton X-100 showed large increases in oligomeric forms of α-Syn suggesting that α-Syn had formed aggregates the mutant mice. In addition, increased levels of p-GSK-3β and pSer396/404 were also found associated with aggregated α-Syn. Differential solubilization to measure protein binding to cytoskeletal proteins demonstrated that p-Tau in the A53T mutant mouse were unbound to cytoskeletal proteins, consistent with dissociation of p-Tau from the microtubules upon hyperphosphorylation. Interestingly, α-Syn remained tightly bound to the cytoskeleton, while p-GSK-3β was seen in the cytoskeleton-free fractions. Immunohistochemical studies showed that α-Syn, pSer396/404 Tau and p-GSK-3β co-localized with one another and was aggregated and accumulated into large inclusion bodies, leading to cell death of Substantia nigral neurons. Together, these data demonstrate an elevated state of

  2. Structures and free energy landscapes of the A53T mutant-type α-synuclein protein and impact of A53T mutation on the structures of the wild-type α-synuclein protein with dynamics.

    Coskuner, Orkid; Wise-Scira, Olivia

    2013-07-17

    utilizing our new theoretical strategy show that the residual secondary structure conversion stabilities resulting in α-helix formation are not significantly affected by the mutation. Interestingly, the residual secondary structure conversion stabilities show that secondary structure conversions resulting in β-sheet formation are influenced by the A53T mutation and the most stable residual transition yielding β-sheet occurs directly from the coil structure. Long-range interactions detected between the NAC region and the N- or C-terminal regions of the wild-type αS disappear upon A53T mutation. The A53T mutant-type αS structures are thermodynamically more stable than those of the wild-type αS protein structures in aqueous solution. Overall, the higher propensity of the A53T mutant-type αS protein to aggregate in comparison to the wild-type αS protein is related to the increased β-sheet formation and lack of strong intramolecular long-range interactions in the N-terminal region in comparison to its wild-type form. The specific residual secondary structure component stabilities reported herein provide information helpful for designing and synthesizing small organic molecules that can block the β-sheet forming residues, which are reactive toward aggregation. PMID:23607785

  3. Olfactory dysfunction and neurotransmitter disturbance in olfactory bulb of transgenic mice expressing human A53T mutant α-synuclein.

    Sufang Zhang

    Full Text Available Parkinson disease is a multi-system neurodegenerative disease characterized by both motor and non-motor symptoms. Hyposmia is one of the early non-motor symptoms occurring in more than 90% of Parkinson disease cases, which can precede motor symptoms even several years. Up to now, the relationship between hyposmia and Parkinson disease remains elusive. Lack of proper animal models of hyposmia restricts the investigation. In this study we assessed olfactory function in Prp-A53T-α-synuclein transgenic (αSynA53T mice which had been reported to show age-dependent motor impairments and intracytoplasmic inclusions. We also examined cholinergic and dopaminergic systems in olfactory bulb of αSynA53T mice by immunofluorescent staining, enzyme linked immunosorbent assay and western blot. We found that compared to wild type littermates, αSynA53T mice at 6 months or older displayed a deficit of odor discrimination and odor detection. No significant changes were found in olfactory memory and odor habituation. Furthermore compared to wildtype littermates, in olfactory bulb of αSynA53T mice at 10 months old we detected a marked decrease of cholinergic neurons in mitral cell layer and a decrease of acetylcholinesterase activity, while dopaminergic neurons were found increased in glomerular layer, accompanied with an increase of tyrosine hydroxylase protein. Our studies indicate that αSynA53T mice have olfactory dysfunction before motor deficits occur, and the cholinergic and dopaminergic disturbance might be responsible for the Parkinson disease-related olfactory dysfunction.

  4. Increased dopaminergic neuron sensitivity to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in transgenic mice expressing mutant A53T alpha-synuclein.

    Yu, Wai Haung; Matsuoka, Yasuji; Sziráki, István; Hashim, Audrey; Lafrancois, John; Sershen, Henry; Duff, Karen E

    2008-05-01

    Familial Parkinson's disease (PD) has been linked to point mutations and duplication of the alpha-synuclein gene and mutant alpha-synuclein expression increases the vulnerability of neurons to exogenous insults. In this study, we analyzed the levels of dopamine and its metabolites in the olfactory bulb (OB), and nigrostriatal regions of transgenic mice expressing human, mutant A53T alpha-synuclein (alpha-syn tg) and their non-transgenic (ntg) littermates using a sub-toxic, moderate dose of MPTP to determine if mutant human alpha-synuclein sensitizes the central dopaminergic systems to oxidative stress. We observed that after a single, sub-lethal MPTP injection, dopamine levels were reduced in striatum and SN in both the alpha-syn tg and ntg mice. In the olfactory bulb, a region usually resistant to MPTP toxicity, levels were reduced only in the alpha-syn tg mice. In addition, we identified a significant increase in dopamine metabolism in the alpha-syn transgenic, but not ntg mice. Finally, MPTP treatment of alpha-syn tg mice was associated with a marked elevation in the oxidative product, 3-nitrotyrosine that co-migrated with alpha-synuclein. Cumulatively, the data support the hypothesis that mutant alpha-synuclein sensitizes dopaminergic neurons to neurotoxic insults and is associated with greater oxidative stress. The alpha-syn tg line is therefore useful to study the genetic and environmental inter-relationship in PD. PMID:17999181

  5. Age-Dependent Effects of A53T Alpha-Synuclein on Behavior and Dopaminergic Function

    Oaks, Adam W; Maya Frankfurt; Finkelstein, David I.; Anita Sidhu

    2013-01-01

    Expression of A53T mutant human alpha-synuclein under the mouse prion promoter is among the most successful transgenic models of Parkinson's disease. Accumulation of A53T alpha-synuclein causes adult mice to develop severe motor impairment resulting in early death at 8-12 months of age. In younger, pre-symptomatic animals, altered motor activity and anxiety-like behaviors have also been reported. These behavioral changes, which precede severe neuropathology, may stem from non-pathological fun...

  6. Site-specific perturbations of alpha-synuclein fibril structure by the Parkinson's disease associated mutations A53T and E46K.

    Luisel R Lemkau

    Full Text Available Parkinson's disease (PD is pathologically characterized by the presence of Lewy bodies (LBs in dopaminergic neurons of the substantia nigra. These intracellular inclusions are largely composed of misfolded α-synuclein (AS, a neuronal protein that is abundant in the vertebrate brain. Point mutations in AS are associated with rare, early-onset forms of PD, although aggregation of the wild-type (WT protein is observed in the more common sporadic forms of the disease. Here, we employed multidimensional solid-state NMR experiments to assess A53T and E46K mutant fibrils, in comparison to our recent description of WT AS fibrils. We made de novo chemical shift assignments for the mutants, and used these chemical shifts to empirically determine secondary structures. We observe significant perturbations in secondary structure throughout the fibril core for the E46K fibril, while the A53T fibril exhibits more localized perturbations near the mutation site. Overall, these results demonstrate that the secondary structure of A53T has some small differences from the WT and the secondary structure of E46K has significant differences, which may alter the overall structural arrangement of the fibrils.

  7. Age-dependent effects of A53T alpha-synuclein on behavior and dopaminergic function.

    Adam W Oaks

    Full Text Available Expression of A53T mutant human alpha-synuclein under the mouse prion promoter is among the most successful transgenic models of Parkinson's disease. Accumulation of A53T alpha-synuclein causes adult mice to develop severe motor impairment resulting in early death at 8-12 months of age. In younger, pre-symptomatic animals, altered motor activity and anxiety-like behaviors have also been reported. These behavioral changes, which precede severe neuropathology, may stem from non-pathological functions of alpha-synuclein, including modulation of monoamine neurotransmission. Our analysis over the adult life-span of motor activity, anxiety-like, and depressive-like behaviors identifies perturbations both before and after the onset of disease. Young A53T mice had increased distribution of the dopamine transporter (DAT to the membrane that was associated with increased striatal re-uptake function. DAT function decreased with aging, and was associated with neurochemical alterations that included increased expression of beta-synuclein and gamma synuclein. Prior to normalization of dopamine uptake, transient activation of Tau kinases and hyperphosphorylation of Tau in the striatum were also observed. Aged A53T mice had reduced neuron counts in the substantia nigra pars compacta, yet striatal medium spiny neuron dendritic spine density was largely maintained. These findings highlight the involvement of the synuclein family of proteins and phosphorylation of Tau in the response to dopaminergic dysfunction of the nigrostriatal pathway.

  8. Astrocytic expression of Parkinson's disease-related A53T α-synuclein causes neurodegeneration in mice

    Gu Xing-Long

    2010-04-01

    Full Text Available Abstract Background Parkinson's disease (PD is the most common movement disorder. While neuronal deposition of α-synuclein serves as a pathological hallmark of PD and Dementia with Lewy Bodies, α-synuclein-positive protein aggregates are also present in astrocytes. The pathological consequence of astrocytic accumulation of α-synuclein, however, is unclear. Results Here we show that PD-related A53T mutant α-synuclein, when selectively expressed in astrocytes, induced rapidly progressed paralysis in mice. Increasing accumulation of α-synuclein aggregates was found in presymptomatic and symptomatic mouse brains and correlated with the expansion of reactive astrogliosis. The normal function of astrocytes was compromised as evidenced by cerebral microhemorrhage and down-regulation of astrocytic glutamate transporters, which also led to increased inflammatory responses and microglial activation. Interestingly, the activation of microglia was mainly detected in the midbrain, brainstem and spinal cord, where a significant loss of dopaminergic and motor neurons was observed. Consistent with the activation of microglia, the expression level of cyclooxygenase 1 (COX-1 was significantly up-regulated in the brain of symptomatic mice and in cultured microglia treated with conditioned medium derived from astrocytes over-expressing A53T α-synuclein. Consequently, the suppression of COX-1 activities extended the survival of mutant mice, suggesting that excess inflammatory responses elicited by reactive astrocytes may contribute to the degeneration of neurons. Conclusions Our findings demonstrate a critical involvement of astrocytic α-synuclein in initiating the non-cell autonomous killing of neurons, suggesting the viability of reactive astrocytes and microglia as potential therapeutic targets for PD and other neurodegenerative diseases.

  9. Revalidation of the isobaric multiplet mass equation at A=53, T=3/2

    J. Su

    2016-05-01

    Full Text Available The T=3/2 isobaric analog state (IAS in 53Co is firmly established through a comprehensive measurement of β-delayed γ and proton decay of 53Ni. The determined excitation energy of 53Co IAS combined with the mass of 53Co generates a precise mass excess of −38333.6(27 keV for the 53Co IAS, which is 70(18 keV lower than the previously adopted value. The new result solves a problem raised by incorrect assignments of the 53Co IAS of unexpected deviation from the isobaric multiplet mass equation (IMME at A=53, T=3/2.

  10. A Swedish family with de novo alpha-synuclein A53T mutation: evidence for early cortical dysfunction

    Puschmann, Andreas; Ross, Owen A; Vilariño-Güell, Carles;

    2009-01-01

    A de novo alpha-synuclein A53T (p.Ala53 Th; c.209G > A) mutation has been identified in a Swedish family with autosomal dominant Parkinson's disease (PD). Two affected individuals had early-onset (before 31 and 40 years), severe levodopa-responsive PD with prominent dysphasia, dysarthria, and...

  11. Behavioral characterization of A53T mice reveals early and late stage deficits related to Parkinson's disease.

    Katrina L Paumier

    Full Text Available Parkinson's disease (PD pathology is characterized by the formation of intra-neuronal inclusions called Lewy bodies, which are comprised of alpha-synuclein (α-syn. Duplication, triplication or genetic mutations in α-syn (A53T, A30P and E46K are linked to autosomal dominant PD; thus implicating its role in the pathogenesis of PD. In both PD patients and mouse models, there is increasing evidence that neuronal dysfunction occurs before the accumulation of protein aggregates (i.e., α-syn and neurodegeneration. Characterization of the timing and nature of symptomatic dysfunction is important for understanding the impact of α-syn on disease progression. Furthermore, this knowledge is essential for identifying pathways and molecular targets for therapeutic intervention. To this end, we examined various functional and morphological endpoints in the transgenic mouse model expressing the human A53T α-syn variant directed by the mouse prion promoter at specific ages relating to disease progression (2, 6 and 12 months of age. Our findings indicate A53T mice develop fine, sensorimotor, and synaptic deficits before the onset of age-related gross motor and cognitive dysfunction. Results from open field and rotarod tests show A53T mice develop age-dependent changes in locomotor activity and reduced anxiety-like behavior. Additionally, digigait analysis shows these mice develop an abnormal gait by 12 months of age. A53T mice also exhibit spatial memory deficits at 6 and 12 months, as demonstrated by Y-maze performance. In contrast to gross motor and cognitive changes, A53T mice display significant impairments in fine- and sensorimotor tasks such as grooming, nest building and acoustic startle as early as 1-2 months of age. These mice also show significant abnormalities in basal synaptic transmission, paired-pulse facilitation and long-term depression (LTD. Combined, these data indicate the A53T model exhibits early- and late-onset behavioral and synaptic

  12. A53T-alpha-synuclein overexpression impairs dopamine signaling and striatal synaptic plasticity in old mice.

    Alexander Kurz

    Full Text Available BACKGROUND: Parkinson's disease (PD, the second most frequent neurodegenerative disorder at old age, can be caused by elevated expression or the A53T missense mutation of the presynaptic protein alpha-synuclein (SNCA. PD is characterized pathologically by the preferential vulnerability of the dopaminergic nigrostriatal projection neurons. METHODOLOGY/PRINCIPAL FINDINGS: Here, we used two mouse lines overexpressing human A53T-SNCA and studied striatal dysfunction in the absence of neurodegeneration to understand early disease mechanisms. To characterize the progression, we employed young adult as well as old mice. Analysis of striatal neurotransmitter content demonstrated that dopamine (DA levels correlated directly with the level of expression of SNCA, an observation also made in SNCA-deficient (knockout, KO mice. However, the elevated DA levels in the striatum of old A53T-SNCA overexpressing mice may not be transmitted appropriately, in view of three observations. First, a transcriptional downregulation of the extraneural DA degradation enzyme catechol-ortho-methytransferase (COMT was found. Second, an upregulation of DA receptors was detected by immunoblots and autoradiography. Third, extensive transcriptome studies via microarrays and quantitative real-time RT-PCR (qPCR of altered transcript levels of the DA-inducible genes Atf2, Cb1, Freq, Homer1 and Pde7b indicated a progressive and genotype-dependent reduction in the postsynaptic DA response. As a functional consequence, long term depression (LTD was absent in corticostriatal slices from old transgenic mice. CONCLUSIONS/SIGNIFICANCE: Taken together, the dysfunctional neurotransmission and impaired synaptic plasticity seen in the A53T-SNCA overexpressing mice reflect early changes within the basal ganglia prior to frank neurodegeneration. As a model of preclinical stages of PD, such insights may help to develop neuroprotective therapeutic approaches.

  13. Comparative docking studies of CYP1b1 and its PCG-associated mutant forms

    Malkaram Sridhar Achary; Hampapathalu Adimurthy Nagarajaram

    2008-12-01

    Molecular docking has been used to compare and contrast the binding modes of oestradiol with the wild-type and some disease-associated mutant forms of the human CYP1b1 protein. The receptor structures used for docking were derived from molecular dynamics simulations of homology-modelled structures. Earlier studies involving molecular dynamics and principal component analysis indicated that mutations could have a disruptive effect on function, by destabilizing the native properties of the functionally important regions, especially those of the haem-binding and substrate-binding regions, which constitute the site of catalytic activity of the enzyme. In order to gain more insights into the possible differences in substrate-binding and catalysis between the wild-type and mutant proteins, molecular docking studies were carried out. Mutants showed altered protein–ligand interactions compared with the wild-type as a consequence of changes in the geometry of the substrate-binding region and in the position of haem relative to the active site. An important difference in ligand–protein interactions between the wild-type and mutants is the presence of stacking interaction with phenyl residues in the wild-type, which is either completely absent or considerably weaker in mutants. The present study revealed essential differences in the interactions between ligand and protein in wild-type and disease mutants, and helped in understanding the deleterious nature of disease mutations at the level of molecular function.

  14. Human GLTP and mutant forms of ACD11 suppress cell death in the Arabidopsis acd11 mutant

    Petersen, Nikolaj H T; McKinney, Lea V; Pike, Helen;

    2008-01-01

    The Arabidopsis acd11 mutant exhibits runaway, programmed cell death due to the loss of a putative sphingosine transfer protein (ACD11) with homology to mammalian GLTP. We demonstrate that transgenic expression in Arabidopsis thaliana of human GLTP partially suppressed the phenotype of the acd11 ...

  15. Crystallization of mutant forms of glutaredoxin Grx1p from yeast

    Glutathionylated glutaredoxin Grx1p from yeast was crystallized, along with a yellow fluorescent protein–glutaredoxin fusion protein. Glutaredoxin Grx1p from yeast was crystallized both as an independent protein and in a protein fusion with His-tagged yellow fluorescent protein (rxYFP). A glutathionylated C30S mutant of the 12 kDa Grx1p was crystallized in two different forms in PEG 4000 at low pH. These orthorhombic and monoclinic forms diffract to 2.0 Å (synchrotron radiation) and 2.7 Å (rotating-anode generator), respectively. In contrast, rxYFP-Grx1p formed crystals at high pH in MgSO4 which diffract synchrotron radiation to 2.7 Å

  16. Resistance to Phytophthora in mutant lines of currant tomato and in their original forms

    Information on the production of currant tomato mutants is contained in a previous report. Evaluation of fruit resistance against Phytophthora infestans (Mont.) de Bary was carried out with pathotypes T0 and T1. For artificial infection we used mainly a culture of T1 (isolate 275), supplied by the Byelorussian Scientific Research Institute of Potato, Fruit and Vegetable Growing at Samokhvalovich. As inoculum for T0, a local population of the potato pathotype from the village of Shebantsevo, Moscow province was used. The standard variety 'Gruntovyj gribovskij 1180' was used as the control. Green fruits were taken from the first or second raceme of 20 plants. They were inoculated by spraying in plastic cuvettes with moist filter paper. The cuvettes were covered with glass and maintained at temperature of 18-20 deg. C. The results were checked 5, 9 and 12 days after inoculation. Under natural conditions, each of the 20 plants was also evaluated. As result, three lines with increased resistance to Phytophthora were selected from the original wild-type of currant tomato. Induced mutant forms were tested in the same way for resistance to Phytophthora. Data is presented from 4 years study. Of 26 mutant lines studied, we identified seven whose fruit displayed a stable and enhanced resistance to Phytophthora under both laboratory and field conditions. With regard to leaf infection of these lines, positive results were not obtained. There appears to be no direct relationship between resistance to Phytophthora of the fruit and the leaves. The mutant lines are of determinate type with early and medium ripening time. The average fruit weight is 5-33 g; in the case of the original specimen, it is only 0.9-1.7 g. The fruits have a pleasant sour-sweet taste and a thick skin. It is noteworthy that the mutant lines selected on the basis of their suitability for cultivation not only showed the resistance selected from the wild-type, but in a number of cases even turned out to be more

  17. Uptake,Subcellular Distribution,and Chemical Forms of Cadmium in Wild-Type and Mutant Rice

    HE Jun-Yu; ZHU Cheng; REN Yan-Fang; YAN Yu-Ping; CHENG Chang; JIANG De-An; SUN Zong-Xiu

    2008-01-01

    Wild-type (Zhonghua 11) and mutant rice (Oryza sativa L.) plants were used to investigate the effect of cadmium (Cd) application on biomass production,to characterize the influx of Cd from roots to shoots,and to determine the form,content,and subcellular distribution of Cd in the roots,leaf sheaths,and leaves of the rice plants.Seedlings were cultivated in a nutrient solution and were treated with 0.5 mmol L-1 of Cd2+ for 14 d.The sensitivity of rice plants to Cd toxicity was tested by studying the changes in biomass production and by observing the onset of toxicity symptoms in the plants.Both the wild-type and mutant rice plants developed symptoms of Cd stress.In addition,Cd application significantly (P ≤ 0.01) decreased dry matter production of roots,leaf sheaths,and leaves of both types,especially the mutant.The Cd content in roots of the mutant was significantly (P≤0.05) higher than that of the wild-type rice.However,there was no significant difference in the Cd content of roots,leaf sheaths,and leaves between the wild-type and mutant rice.Most of the Cd was bound to the cell wall of the roots,leaf sheaths,and leaves,and the mutant had greater Cd content in cell organelles than the wild type.The uneven subcellular distribution could be responsible for the Cd sensitivity of the mutant rice.Furthermore,different chemical forms of Cd were found to occur in the roots,leaf sheaths,and leaves of both types of rice plants.Ethanol-,water-,and NaCl-extractable Cd had greater toxicity than the other forms of Cd and induced stunted growth and chlorosls in the plants.The high Cd content of the toxic forms of Cd in the cell organelles could seriously damage the cells and the metabolic processes in mutant rice plants.

  18. Allergenic Characterization of New Mutant Forms of Pru p 3 as New Immunotherapy Vaccines

    C. Gómez-Casado

    2013-01-01

    Full Text Available Nowadays, treatment of food allergy only considered the avoidance of the specific food. However, the possibility of cross-reactivity makes this practice not very effective. Immunotherapy may exhibit as a good alternative to food allergy treatment. The use of hypoallergenic molecules with reduced IgE binding capacity but with ability to stimulate the immune system is a promising tool which could be developed for immunotherapy. In this study, three mutants of Pru p 3, the principal allergen of peach, were produced based on the described mimotope and T cell epitopes, by changing the specific residues to alanine, named as Pru p 3.01, Pru p 3.02, and Pru p 3.03. Pru p 3.01 showed very similar allergenic activity as the wild type by in vitro assays. However, Pru p 3.02 and Pru p 3.03 presented reduced IgE binding with respect to the native form, by in vitro, ex vivo, and in vivo assays. In addition, Pru p 3.03 had affected the IgG4 binding capacity and presented a random circular dichroism, which was reflected in the nonrecognition by specific antibodies anti-Pru p 3. Nevertheless, both Pru p 3.02 and Pru p 3.03 maintained the binding to IgG1 and their ability to activate T lymphocytes. Thus, Pru p 3.02 and Pru p 3.03 could be good candidates for potential immunotherapy in peach-allergic patients.

  19. Repressor Mutant Forms of the Azospirillum brasilense NtrC Protein

    Huergo, Luciano F.; Assumpção, Marcelo C.; Emanuel M. Souza; Steffens, M. Berenice R.; Yates, M. Geoffrey; Chubatsu, Leda S; Pedrosa, Fábio O.

    2004-01-01

    The Azospirillum brasilense mutant strains FP8 and FP9, after treatment with nitrosoguanidine, showed a null Nif phenotype and were unable to use nitrate as their sole nitrogen source. Sequencing of the ntrC genes revealed single nucleotide mutations in the NtrC nucleotide-binding site. The phenotypes of these strains are discussed in relation to their genotypes.

  20. Photolabelling of mutant forms of the S1 subunit of pertussis toxin with NAD+.

    Cieplak, W; Locht, C; Mar, V L; Burnette, W N; Keith, J M

    1990-01-01

    The S1 subunit of pertussis toxin catalyses the hydrolysis of NAD+ (NAD+ glycohydrolysis) and the NAD(+)-dependent ADP-ribosylation of guanine-nucleotide-binding proteins. Recently, the S1 subunit of pertussis toxin was shown to be photolabelled by using radiolabelled NAD+ and u.v.; the primary labelled residue was Glu-129, thereby implicating this residue in the binding of NAD+. Studies from various laboratories have shown that the N-terminal portion of the S1 subunit, which shows sequence similarity to cholera toxin and Escherichia coli heat-labile toxin, is important to the maintenance of both glycohydrolase and transferase activity. In the present study the photolabelling technique was applied to the analysis of a series of recombinant-derived S1 molecules that possessed deletions or substitutions near the N-terminus of the S1 molecule. The results revealed a positive correlation between the extent of photolabelling with NAD+ and the magnitude of specific NAD+ glycohydrolase activity exhibited by the mutants. Enzyme kinetic analyses of the N-terminal mutants also identified a mutant with substantially reduced activity, a depressed photolabelling efficiency and a markedly increased Km for NAD+. The results support a direct role for the N-terminal region of the S1 subunit in the binding of NAD+, thereby providing a rationale for the effect of mutations in this region on enzymic activity. Images Fig. 1. PMID:2363691

  1. Single-molecule FRET studies on alpha-synuclein oligomerization of Parkinson’s disease genetically related mutants

    Tosatto, Laura; Horrocks, Mathew H.; Dear, Alexander J.; Knowles, Tuomas P. J.; Dalla Serra, Mauro; Cremades, Nunilo; Dobson, Christopher M.; Klenerman, David

    2015-11-01

    Oligomers of alpha-synuclein are toxic to cells and have been proposed to play a key role in the etiopathogenesis of Parkinson’s disease. As certain missense mutations in the gene encoding for alpha-synuclein induce early-onset forms of the disease, it has been suggested that these variants might have an inherent tendency to produce high concentrations of oligomers during aggregation, although a direct experimental evidence for this is still missing. We used single-molecule Förster Resonance Energy Transfer to visualize directly the protein self-assembly process by wild-type alpha-synuclein and A53T, A30P and E46K mutants and to compare the structural properties of the ensemble of oligomers generated. We found that the kinetics of oligomer formation correlates with the natural tendency of each variant to acquire beta-sheet structure. Moreover, A53T and A30P showed significant differences in the averaged FRET efficiency of one of the two types of oligomers formed compared to the wild-type oligomers, indicating possible structural variety among the ensemble of species generated. Importantly, we found similar concentrations of oligomers during the lag-phase of the aggregation of wild-type and mutated alpha-synuclein, suggesting that the properties of the ensemble of oligomers generated during self-assembly might be more relevant than their absolute concentration for triggering neurodegeneration.

  2. A Nonoligomerizing Mutant Form of Helicobacter pylori VacA Allows Structural Analysis of the p33 Domain.

    González-Rivera, Christian; Campbell, Anne M; Rutherford, Stacey A; Pyburn, Tasia M; Foegeding, Nora J; Barke, Theresa L; Spiller, Benjamin W; McClain, Mark S; Ohi, Melanie D; Lacy, D Borden; Cover, Timothy L

    2016-09-01

    Helicobacter pylori secretes a pore-forming VacA toxin that has structural features and activities substantially different from those of other known bacterial toxins. VacA can assemble into multiple types of water-soluble flower-shaped oligomeric structures, and most VacA activities are dependent on its capacity to oligomerize. The 88-kDa secreted VacA protein can undergo limited proteolysis to yield two domains, designated p33 and p55. The p33 domain is required for membrane channel formation and intracellular toxic activities, and the p55 domain has an important role in mediating VacA binding to cells. Previous studies showed that the p55 domain has a predominantly β-helical structure, but no structural data are available for the p33 domain. We report here the purification and analysis of a nonoligomerizing mutant form of VacA secreted by H. pylori The nonoligomerizing 88-kDa mutant protein retains the capacity to enter host cells but lacks detectable toxic activity. Analysis of crystals formed by the monomeric protein reveals that the β-helical structure of the p55 domain extends into the C-terminal portion of p33. Fitting the p88 structural model into an electron microscopy map of hexamers formed by wild-type VacA (predicted to be structurally similar to VacA membrane channels) reveals that p55 and the β-helical segment of p33 localize to peripheral arms but do not occupy the central region of the hexamers. We propose that the amino-terminal portion of p33 is unstructured when VacA is in a monomeric form and that it undergoes a conformational change during oligomer assembly. PMID:27382020

  3. Molecular Dynamics Approach in the Comparison of Wild-Type and Mutant Paraoxonase-1 Apoenzyme Form

    Amine, Khadija; Miri, Lamia; Naimi, Adil; Saile, Rachid; El Kharrim, Abderrahmane; Mikou, Afaf; Kettani, Anass

    2015-01-01

    There is some evidence linking the mammalian paraoxonase-1 (PON1) loops (L1 and L2) to an increased flexibility and reactivity of its active site with potential substrates. The aim of this work is to study the structural, dynamical, and functional effects of the most flexible regions close to the active site and to determine the impact of mutations on the protein. For both models, wild-type (PON1wild) and PON1 mutant (PON1mut) models, the L1 loop and Q/R and L/M mutations were constructed using MODELLER software. Molecular dynamics simulations of 20 ns at 300 K on fully modeled PON1wild and PON1mut apoenzyme have been done. Detailed analyses of the root-mean-square deviation and fluctuations, H-bonding pattern, and torsion angles have been performed. The PON1wild results were then compared with those obtained for the PON1mut. Our results show that the active site in the wild-type structure is characterized by two distinct movements of opened and closed conformations of the L1 and L2 loops. The alternating and repetitive movement of loops at specific times is consistent with the presence of 11 defined hydrogen bonds. In the PON1mut, these open-closed movements are therefore totally influenced and repressed by the Q/R and L/M mutations. In fact, these mutations seem to impact the PON1mut active site by directly reducing the catalytic core flexibility, while maintaining a significant mobility of the switch regions delineated by the loops surrounding the active site. The impact of the studied mutations on structure and dynamics proprieties of the protein may subsequently contribute to the loss of both flexibility and activity of the PON1 enzyme. PMID:26417201

  4. Changes in adult olfactory bulb neurogenesis in mice expressing the A30P mutant form of alpha-synuclein.

    Marxreiter, Franz; Nuber, Silke; Kandasamy, Mahesh; Klucken, Jochen; Aigner, Robert; Burgmayer, Ralf; Couillard-Despres, Sebastien; Riess, Olaf; Winkler, Jürgen; Winner, Beate

    2009-03-01

    In familial and sporadic forms of Parkinson's disease (PD), alpha-synuclein pathology is present in the brain stem nuclei and olfactory bulb (OB) long before Lewy bodies are detected in the substantia nigra. The OB is an active region of adult neurogenesis, where newly generated neurons physiologically integrate. While accumulation of wild-type alpha-synuclein is one of the pathogenic hallmarks of non-genetic forms of PD, the A30P alpha-synuclein mutation results in an earlier disease onset and a severe clinical phenotype. Here, we study the regulation of adult neurogenesis in the subventricular zone (SVZ)/OB system in a tetracycline-suppressive (tet-off) transgenic model of synucleinopathies, expressing human mutant A30P alpha-synuclein under the control of the calcium/calmodulin-dependent protein kinase II alpha (CaMK) promoter. In A30P transgenic mice alpha-synuclein was abundant at the site of integration in the glomerular cell layer of the OB. Without changes in proliferation in the SVZ, significantly fewer newly generated neurons were observed in the OB granule cell and glomerular layers of A30P transgenic mice than in controls, most probably due to increased cell death. By tetracycline-dependent abrogation of A30P alpha-synuclein expression, OB neurogenesis and programmed cell death was restored to control levels. Our results indicate that, using A30P conditional (tet-off) mice, A30P alpha-synuclein has a negative impact on olfactory neurogenesis and suppression of A30P alpha-synuclein enhances survival of newly generated neurons. This finding suggests that interfering with alpha-synuclein pathology can rescue newly generated neurons, possibly leading to new targets for therapeutic interventions in synucleinopathies. PMID:19291219

  5. Purification, crystallization and preliminary X-ray analysis of truncated and mutant forms of VP4 protease from infectious pancreatic necrosis virus

    Various truncated and mutant forms of the protease VP4 from infectious pancreatic necrosis virus were used to generate two different crystal forms of VP4 which diffracted to beyond 2.4 Å resolution. In viruses belonging to the Birnaviridae family, virus protein 4 (VP4) is the viral protease responsible for the proteolytic maturation of the polyprotein encoding the major capsid proteins (VP2 and VP3). Infectious pancreatic necrosis virus (IPNV), the prototype of the aquabirnavirus genus, is the causative agent of a contagious disease in fish which has a large economic impact on aquaculture. IPNV VP4 is a 226-residue (24.0 kDa) serine protease that utilizes a Ser/Lys catalytic dyad mechanism (Ser633 and Lys674). Several truncated and mutant forms of VP4 were expressed in a recombinant expression system, purified and screened for crystallization. Two different crystal forms diffract beyond 2.4 Å resolution. A triclinic crystal derived from one mutant construct has unit-cell parameters a = 41.7, b = 69.6, c = 191.6 Å, α = 93.0, β = 95.1, γ = 97.7°. A hexagonal crystal with space group P6122/P6522 derived from another mutant construct has unit-cell parameters a = 77.4, b = 77.4, c = 136.9 Å

  6. Immunization with a Recombinant, Pseudomonas fluorescens-Expressed, Mutant Form of Bacillus anthracis-Derived Protective Antigen Protects Rabbits from Anthrax Infection.

    Matthew D Reed

    Full Text Available Protective antigen (PA, one of the components of the anthrax toxin, is the major component of human anthrax vaccine (Biothrax. Human anthrax vaccines approved in the United States and Europe consist of an alum-adsorbed or precipitated (respectively supernatant material derived from cultures of toxigenic, non-encapsulated strains of Bacillus anthracis. Approved vaccination schedules in humans with either of these vaccines requires several booster shots and occasionally causes adverse injection site reactions. Mutant derivatives of the protective antigen that will not form the anthrax toxins have been described. We have cloned and expressed both mutant (PA SNKE167-ΔFF-315-E308D and native PA molecules recombinantly and purified them. In this study, both the mutant and native PA molecules, formulated with alum (Alhydrogel, elicited high titers of anthrax toxin neutralizing anti-PA antibodies in New Zealand White rabbits. Both mutant and native PA vaccine preparations protected rabbits from lethal, aerosolized, B. anthracis spore challenge subsequent to two immunizations at doses of less than 1 μg.

  7. Mutant CAG repeats of Huntingtin transcript fold into hairpins, form nuclear foci and are targets for RNA interference

    de Mezer, Mateusz; Wojciechowska, Marzena; Napierala, Marek; Sobczak, Krzysztof; Krzyzosiak, Wlodzimierz J.

    2011-01-01

    The CAG repeat expansions that occur in translated regions of specific genes can cause human genetic disorders known as polyglutamine (poly-Q)-triggered diseases. Huntington’s disease and spinobulbar muscular atrophy (SBMA) are examples of these diseases in which underlying mutations are localized near other trinucleotide repeats in the huntingtin (HTT) and androgen receptor (AR) genes, respectively. Mutant proteins that contain expanded polyglutamine tracts are well-known triggers of pathoge...

  8. Crystallization and preliminary crystallographic analysis of decameric and monomeric forms of C49S mutant thioredoxin-dependent AhpC from Helicobacter pylori

    Supangat [Division of Applied Life Science (BK21 Program), Gyeongsang National University, Jinju 660-701 (Korea, Republic of); Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701 (Korea, Republic of); Seo, Kyung Hye; Furqoni, Ahmad [Division of Applied Life Science (BK21 Program), Gyeongsang National University, Jinju 660-701 (Korea, Republic of); Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701 (Korea, Republic of); Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701 (Korea, Republic of); Kwon, Young-Chul; Cho, Myung-Je; Rhee, Kwang-Ho [Department of Microbiology, School of Medicine, Gyeongsang National University, Jinju 660-701 (Korea, Republic of); Lee, Sang Yeol; Lee, Kon Ho, E-mail: lkh@gsnu.ac.kr [Division of Applied Life Science (BK21 Program), Gyeongsang National University, Jinju 660-701 (Korea, Republic of); Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701 (Korea, Republic of); Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701 (Korea, Republic of)

    2008-05-01

    Decameric and monomeric forms of recombinant C49S mutant AhpC from H. pylori have been crystallized. Diffraction data were collected to 2.8 and 2.25 Å, respectively. Cys49Ser mutant Helicobacter pylori alkyl hydroperoxide reductase (C49S HpAhpC) was purified under reducing conditions in monomeric and decameric forms. The monomeric form was crystallized by the hanging-drop vapour-diffusion method. The crystals diffracted to 2.25 Å resolution and belonged to space group C2, with unit-cell parameters a = 245.8, b = 140.7, c = 189.5 Å, β = 127°, and contained 20 molecules in the asymmetric unit. A crystal of the decameric form was obtained by the microbatch crystallization method and diffracted to 2.8 Å resolution. It belonged to space group C222, with unit-cell parameters a = 257.5, b = 417.5, c = 95.6 Å. The structure of the monomeric form of C49S HpAhpC has been solved by the molecular-replacement method.

  9. Spectral characteristics of the mutant form GGBP/H152C of D-glucose/D-galactose-binding protein labeled with fluorescent dye BADAN: influence of external factors

    Alexander V. Fonin

    2014-03-01

    Full Text Available The mutant form GGBP/H152C of the D-glucose/D-galactose-binding protein with the solvatochromic dye BADAN linked to cysteine residue Cys 152 can be used as a potential base for a sensitive element of glucose biosensor system. We investigated the influence of various external factors on the physical-chemical properties of GGBP/H152C-BADAN and its complex with glucose. The high affinity (Kd = 8.5 µM and high binding rate of glucose make GGBP/H152C-BADAN a good candidate to determine the sugar content in biological fluids extracted using transdermal techniques. It was shown that changes in the ionic strength and pH of solution within the physiological range did not have a significant influence on the fluorescent characteristics of GGBP/H152C-BADAN. The mutant form GGBP/H152C has relatively low resistance to denaturation action of GdnHCl and urea. This result emphasizes the need to find more stable proteins for the creation of a sensitive element for a glucose biosensor system.

  10. Slow formation of [3Fe-4S](1+) clusters in mutant forms of Desulfovibrio africanus ferredoxin III.

    Hannan, J P; Busch, J L; James, R; Thomson, A J; Moore, G R; Davy, S L

    2000-02-25

    Desulfovibrio africanus ferredoxin III (Da FdIII) readily interconverts between a 7Fe and an 8Fe form with Asp-14 believed to provide a cluster ligand in the latter form. To investigate the factors important for cluster interconversion in Fe/S cluster-containing proteins we have studied two variants of Da FdIII produced by site-directed mutagenesis, Asp14Glu and Asp14His, with cluster incorporation performed in vitro. Characterisation of these proteins by UV/visible, EPR and (1)H NMR spectroscopies revealed that the formation of the stable 7Fe form of these proteins takes some time to occur. Evidence is presented which indicates the [4Fe-4S](2+) cluster is incorporated prior to the [3Fe-4S](1+) cluster. PMID:10692579

  11. The capacity of Listeria monocytogenes mutants with in-frame deletions in putative ATP-binding cassette transporters to form biofilms and comparison with the wild type

    Marina Ceruso

    2014-02-01

    Full Text Available Listeria monocytogenes (Lm is a food-borne pathogen responsible for human listeriosis, an invasive infection with high mortality rates. Lm has developed efficient strategies for survival under stress conditions such as starvation and wide variations in temperature, pH, and osmolarity. Therefore, Lm can survive in food under multiple stress conditions. Detailed studies to determine the mode of action of this pathogen for survival under stress conditions are important to control Lm in food. It has been shown that genes encoding for ATP-binding cassette (ABC transporters are induced in Lm in food, in particular under stress conditions. Previous studies showed that these genes are involved in sensitivity to nisin, acids, and salt. The aim of this study was to determine the involvement of some ABC transporters in biofilm formation. Therefore, deletion mutants of ABC transporter genes (LMOf2365_1875 and LMOf2365_1877 were created in Lm F2365, and then were compared to the wild type for their capacity to form biofilms. Lm strain F2365 was chosen as reference since the genome is fully sequenced and furthermore this strain is particularly involved in food-borne outbreaks of listeriosis. Our results showed that DLMOf2365_1875 had an increased capacity to form biofilms compared to the wild type, indicating that LMOf2365_1875 negatively regulates biofilm formation. A deeper knowledge on the ability to form biofilms in these mutants may help in the development of intervention strategies to control Lm in food and in the environment.

  12. The structures of mutant forms of Hfq from Pseudomonas aeruginosa reveal the importance of the conserved His57 for the protein hexamer organization

    The results obtained demonstrate the great importance of solvent-inaccessible conserved hydrogen bonds between the Hfq monomers in the stabilization of the hexamer structure. The bacterial Sm-like protein Hfq forms homohexamers both in solution and in crystals. The monomers are organized as a continuous β-sheet passing through the whole hexamer ring with a common hydrophobic core. Analysis of the Pseudomonas aeruginosa Hfq (PaeHfq) hexamer structure suggested that solvent-inaccessible intermonomer hydrogen bonds created by conserved amino-acid residues should also stabilize the quaternary structure of the protein. In this work, one such conserved residue, His57, in PaeHfq was replaced by alanine, threonine or asparagine. The crystal structures of His57Thr and His57Ala Hfq were determined and the stabilities of all of the mutant forms and of the wild-type protein were measured. The results obtained demonstrate the great importance of solvent-inaccessible conserved hydrogen bonds between the Hfq monomers in stabilization of the hexamer structure

  13. Highly ordered crystals of channel-forming membrane proteins, of nucleoside-monophosphate kinases, of FAD-containing oxidoreductases and of sugar-processing enzymes and their mutants

    Schulz, G. E.; Dreyer, M.; Klein, C.; Kreusch, A.; Mittl, P.; Mu¨ller, C. W.; Mu¨ller-Dieckmann, J.; Muller, Y. A.; Proba, K.; Schlauderer, G.; Spu¨rgin, P.; Stehle, T.; Weiss, M. S.

    1992-08-01

    Preparation and crystallization procedures as well as crystal properties are reported for 12 proteins plus numerous site-directed mutants. The proteins are: the integral membrane protein porin from Rhodobacter capsulatus which diffracts to at least 1.8A˚resolution, porin from Rhodopseudomonas blastica which diffracts to at least 2.0A˚resolution, adenylate kinase from yeast and mutants, adenylate kinase from Escherichia coli and mutants, bovine liver mitochondrial adenylate kinase, guanylate kinase from yeast, uridylate kinase from yeast, glutathione reductase from E. coli and mutants, NADH peroxidase from Streptococcus faecalis containing a sulfenic acid as redox-center, pyruvate oxidase from Lactobacillus plantarum containing FAD and TPP, cyclodextrin glycosyltransferase from Bacillus circulans and mutants, and a fuculose aldolase from E. coli.

  14. Expression of human A53T alpha-synuclein in the rat substantia nigra using a novel AAV1/2 vector produces a rapidly evolving pathology with protein aggregation, dystrophic neurite architecture and nigrostriatal degeneration with potential to model the pathology of Parkinson's disease

    Sun Xuan

    2010-10-01

    Full Text Available Abstract Background The pathological hallmarks of Parkinson's disease (PD include the presence of alpha-synuclein (α-syn rich Lewy bodies and neurites and the loss of dopaminergic (DA neurons of the substantia nigra (SN. Animal models of PD based on viral vector-mediated over-expression of α-syn have been developed and show evidence of DA toxicity to varying degrees depending on the type of virus used, its concentration, and the serotype of vector employed. To date these models have been variable, difficult to reproduce, and slow in their evolution to achieve a desired phenotype, hindering their use as a model for testing novel therapeutics. To address these issues we have taken a novel vector in this context, that can be prepared in high titer and which possesses an ability to produce neuronally-directed expression, with expression dynamics optimised to provide a rapid rise in gene product expression. Thus, in the current study, we have used a high titer chimeric AAV1/2 vector, to express human A53T α-syn, an empty vector control (EV, or green fluorescent protein (GFP, the latter to control for the possibility that high levels of protein in themselves might contribute to damage. Results We show that following a single 2 μl injection into the rat SN there is near complete coverage of the structure and expression of A53T α-syn or GFP appears throughout the striatum. Within 3 weeks of SN delivery of their respective vectors, aggregations of insoluble α-syn were observed in SN DA neurons. The numbers of DA neurons in the SN were significantly reduced by expression of A53T α-syn (52%, and to a lesser extent by GFP (24%, compared to EV controls (both P P Conclusions In the current implementation of the model, we recapitulate the primary pathological hallmarks of PD, although a proportion of the SN damage may relate to general protein overload and may not be specific for A53T α-syn. Future studies will thus be required to optimise the dose of

  15. Assessment of EGFR mutation status in lung adenocarcinoma by immunohistochemistry using antibodies specific to the two major forms of mutant EGFR.

    Brevet, Marie; Arcila, Maria; Ladanyi, Marc

    2010-03-01

    EGFR mutations are the best predictors of response to EGFR kinase inhibitors in lung adenocarcinoma. We evaluated two mutation-specific monoclonal antibodies for the detection of EGFR mutations by immunohistochemistry (IHC), generated respectively against the L858R mutant and the exon 19 mutant with the common 15bp/5AA deletion. These two mutations account for approximately 90% of all EGFR mutations. IHC staining performed on 218 paraffin-embedded lung adenocarcinomas was assessed on a 0 to 3+ scale, and positivity cutoffs of 1+ and 2+ were compared. All cases were studied by standard molecular methods for these two mutations, and selected cases were also studied using higher sensitivity molecular assays. The EGFR L858R mutant antibody showed a sensitivity of 95% and a positive predictive value (PPV) of 99% with a positivity cutoff of 1+ and a sensitivity of 76% and a PPV of 100% with a positivity cutoff of 2+. The EGFR exon 19 mutant-specific antibody showed reduced sensitivity for exon 19 deletions other than 15bp. A positivity cutoff of 1+ resulted in a sensitivity of 85% and a PPV of 99%, whereas a 2+ cutoff gave a sensitivity of 67% and a PPV of 100%. IHC with EGFR mutant-specific antibodies could be used as a screen to identify most candidates for EGFR inhibitors. PMID:20093391

  16. A mutant form of maltose-binding protein of Escherichia coli deficient in its interaction with the bacteriophage lambda receptor protein.

    Bavoil, P; Wandersman, C; Schwartz, M; Nikaido, H

    1983-01-01

    In one malE mutant known to be deficient in the transport of maltose and maltodextrins across the outer membrane, the altered MalE protein was shown to be defective in its interaction with the phage lambda receptor, or LamB protein, of the outer membrane.

  17. Crystallization and preliminary X-ray analysis of a decameric form of cytosolic thioredoxin peroxidase 1 (Tsa1), C47S mutant, from Saccharomyces cerevisiae

    de Oliveira, Marcos Antonio; Genu, Victor; Discola, Karen Fulan; Alves, Simone Vidigal; Netto, Luis Eduardo Soares; Guimarães, Beatriz Gomes

    2007-01-01

    A recombinant mutant (C47S) of cytosolic thioredoxin peroxidase 1 from S. cerevisiae was expressed, purified and crystallized by the hanging-drop vapour-diffusion method from protein previously treated with 1,4-dithiothreitol. The crystals belong to the monoclinic space group C2 and diffraction data were collected to 2.8 Å resolution using a synchrotron-radiation source.

  18. Crystallization and preliminary X-ray analysis of a decameric form of cytosolic thioredoxin peroxidase 1 (Tsa1), C47S mutant, from Saccharomyces cerevisiae

    A recombinant mutant (C47S) of cytosolic thioredoxin peroxidase 1 from S. cerevisiae was expressed, purified and crystallized by the hanging-drop vapour-diffusion method from protein previously treated with 1,4-dithiothreitol. The crystals belong to the monoclinic space group C2 and diffraction data were collected to 2.8 Å resolution using a synchrotron-radiation source. Saccharomyces cerevisiae cytosolic thioredoxin peroxidase 1 (cTPxI or Tsa1) is a bifunctional enzyme with protective roles in cellular defence against oxidative and thermal stress that exhibits both peroxidase and chaperone activities. Protein overoxidation and/or high temperatures induce great changes in its quaternary structure and lead to its assembly into large complexes that possess chaperone activity. A recombinant mutant of Tsa1 from S. cerevisiae, with Cys47 substituted by serine, was overexpressed in Escherichia coli as a His6-tagged fusion protein and purified by nickel-affinity chromatography. Crystals were obtained from protein previously treated with 1,4-dithiothreitol by the hanging-drop vapour-diffusion method using PEG 3000 as precipitant and sodium fluoride as an additive. Diffraction data were collected to 2.8 Å resolution using a synchrotron-radiation source. The crystal structure was solved by molecular-replacement methods and structure refinement is currently in progress

  19. Systematic strain construction and process development: Xylitol production by Saccharomyces cerevisiae expressing Candida tenuis xylose reductase in wild-type or mutant form.

    Pratter, S M; Eixelsberger, T; Nidetzky, B

    2015-12-01

    A novel Saccharomyces cerevisiae whole-cell biocatalyst for xylitol production based on Candida tenuis xylose reductase (CtXR) is presented. Six recombinant strains expressing wild-type CtXR or an NADH-specific mutant were constructed and evaluated regarding effects of expression mode, promoter strength, biocatalyst concentration and medium composition. Intracellular XR activities ranged from 0.09 U mgProt(-1) to 1.05 U mgProt(-1) but did not correlate with the strains' xylitol productivities, indicating that other factors limited xylose conversion in the high-activity strains. The CtXR mutant decreased the biocatalyst's performance, suggesting use of the NADPH-preferring wild-type enzyme when (semi-)aerobic conditions are applied. In a bioreactor process, the best-performing strain converted 40 g L(-1) xylose with an initial productivity of 1.16 g L(-1)h(-1) and a xylitol yield of 100%. The obtained results underline the potential of CtXR wild-type for xylose reduction and point out parameters to improve "green" xylitol production. PMID:26452180

  20. Connexin mutants and cataracts

    EricCBeyer

    2013-04-01

    Full Text Available The lens is a multicellular, but avascular tissue that must stay transparent to allow normal transmission of light and focusing of it on the retina. Damage to lens cells and/or proteins can cause cataracts, opacities that disrupt these processes. The normal survival of the lens is facilitated by an extensive network of gap junctions formed predominantly of connexin46 and connexin50. Mutations of the genes that encode these connexins (GJA3 and GJA8 have been identified and linked to inheritance of cataracts in human families and mouse lines. In vitro expression studies of several of these mutants have shown that they exhibit abnormalities that may lead to disease. Many of the mutants reduce or modify intercellular communication due to channel alterations (including loss of function or altered gating or due to impaired cellular trafficking which reduces the number of gap junction channels within the plasma membrane. However, the abnormalities detected in studies of other mutants suggest that they cause cataracts through other mechanisms including gain of hemichannel function (leading to cell injury and death and formation of cytoplasmic accumulations (that may act as light scattering particles. These observations and the anticipated results of ongoing studies should elucidate the mechanisms of cataract development due to mutations of lens connexins and abnormalities of other lens proteins. They may also contribute to our understanding of the mechanisms of disease due to connexin mutations in other tissues.

  1. Using the MCF10A/MCF10CA1a Breast Cancer Progression Cell Line Model to Investigate the Effect of Active, Mutant Forms of EGFR in Breast Cancer Development and Treatment Using Gefitinib.

    Darrell C Bessette

    Full Text Available Basal-like and triple negative breast cancer (TNBC share common molecular features, poor prognosis and a propensity for metastasis to the brain. Amplification of epidermal growth factor receptor (EGFR occurs in ~50% of basal-like breast cancer, and mutations in the epidermal growth factor receptor (EGFR have been reported in up to ~ 10% of Asian TNBC patients. In non-small cell lung cancer several different mutations in the EGFR tyrosine kinase domain confer sensitivity to receptor tyrosine kinase inhibitors, but the tumourigenic potential of EGFR mutations in breast cells and their potential for targeted therapy is unknown.Constructs containing wild type, G719S or E746-A750 deletion mutant forms of EGFR were transfected into the MCF10A breast cells and their tumorigenic derivative, MCF10CA1a. The effects of EGFR over-expression and mutation on proliferation, migration, invasion, response to gefitinib, and tumour formation in vivo was investigated. Copy number analysis and whole exome sequencing of the MCF10A and MCF10CA1a cell lines were also performed.Mutant EGFR increased MCF10A and MCF10CA1a proliferation and MCF10A gefitinib sensitivity. The EGFR-E746-A750 deletion increased MCF10CA1a cell migration and invasion, and greatly increased MCF10CA1a xenograft tumour formation and growth. Compared to MCF10A cells, MCF10CA1a cells exhibited large regions of gain on chromosomes 3 and 9, deletion on chromosome 7, and mutations in many genes implicated in cancer.Mutant EGFR enhances the oncogenic properties of MCF10A cell line, and increases sensitivity to gefitinib. Although the addition of EGFR E746-A750 renders the MCF10CA1a cells more tumourigenic in vivo it is not accompanied by increased gefitinib sensitivity, perhaps due to additional mutations, including the PIK3CA H1047R mutation, that the MCF10CA1a cell line has acquired. Screening TNBC/basal-like breast cancer for EGFR mutations may prove useful for directing therapy but, as in non

  2. Biofilm Formation by Hyperpiliated Mutants of Pseudomonas aeruginosa

    Chiang, Poney; Burrows, Lori L.

    2003-01-01

    Under static growth conditions, hyperpiliated, nontwitching pilT and pilU mutants of Pseudomonas aeruginosa formed dense biofilms, showing that adhesion, not twitching motility, is necessary for biofilm initiation. Under flow conditions, the pilT mutant formed mushroom-like structures larger than those of the wild type but the pilU mutant was defective in biofilm formation. Therefore, twitching motility affects the development of biofilm structure, possibly through modulation of detachment.

  3. Productive mutants of niger

    Seeds of six niger (Guizotia abyssinica Cass.) varieties ('GA-10', 'ONS-8', 'IGP-72', 'N-71', 'NB-9' and 'UN-4') were treated with 0.5, 0.75 and 1% ethyl methanesulphonate. After four generations of selection, 29 mutant lines were developed and those were evaluated from 1990-92 during Kharif (July to October) and Rabi (December to March) seasons. Average plant characteristics and yield data of four high yielding mutants along with 'IGP-76' (National Check), GA-10 (Zonal Check) and 'Semiliguda Local' (Local Check) are presented

  4. Visual modeling mutants for D-lactate dehydrogenase form aquifex aeolicus and the effect of mutants on the production of phenyl lactate acid in E.coli%耐热菌D-乳酸脱氢酶突变体的可视化建模和大肠杆菌中突变体对产苯乳酸的影响

    田晋红; 刘琦; 战丽萍; 李小丽

    2012-01-01

    Based on bioinformatics,the amino acid residues of conservative and activity center of D-lactate dehydrogenase(D-LDH),and the three-dimensional structure model of protein was analysised.The space conformation of visualization mutant had been constructed by homology modeling,the best mutant models were selected by the calculation of the distance and angle.The results showed that the 4 amino acid residues were relevant to the activity center in 20 conservative residues of D-LDH.After the models were compared,it was found that the big molecules substrates were obstructed by the benzyl of the residues of Phenylalanine(phe)or Tyrosine(try)on the 49 and 297 position.When F49A,Y279A,F49A and Y279A were mutated,the obstacles would disappear or weaken.The three mutants constructed were made a preliminary study,the results showed that IPTG or lactose could induce mutant to produce phenyl lactic acid in E.coli.The yield of phenyl lactic acid was higher in static culture than in vibration incubator,and the one of the F49A mutant(A.a.D-LDH-F49A strains)was higher than the one of the wild type(A.a.D-LDH strains)with lactose inducing.It would be a method of constructing gene engineering strain that visualization mutants models were compared and selected.%以生物信息学为基础,分析D-乳酸脱氢酶(D-LDH)的保守氨基酸残基、活性中心氨基酸残基、蛋白质三维结构和同源建模,可视化比较建模突变体空间构象,优选最佳突变体模型。结果显示,在D-LDH的20个保守氨基酸中,4个与酶活性中心有关。比较突变体模型发现,49和297位的phe或try的苯环形成空间位阻,F49A或Y279A及F49A和Y279A双突变体可解除位阻。对已构建的三个突变体初步发酵显示,IPTG和乳糖都能诱导突变体酶在大肠杆菌中产生苯乳酸,静置培养比摇振培养产量高,用乳糖诱导时,突变体F49A(A.a D-LDH-F49A株)苯乳酸的量比野生型(A.a.D-LDH株)的高。优选可视化突变体可

  5. Iron-molybdenum cofactor synthesis in Azotobacter vinelandii Nif- mutants.

    Imperial, J; Shah, V K; Ugalde, R A; Ludden, P W; Brill, W J

    1987-01-01

    Nif- mutants of Azotobacter vinelandii defective in dinitrogenase activity synthesized iron-molybdenum cofactor (FeMo-co) and accumulated it in two protein-bound forms: inactive dinitrogenase and a possible intermediate involved in the FeMo-co biosynthetic pathway. FeMo-co from both these proteins could activate apo-dinitrogenase from FeMo-co-deficient mutants.

  6. Morphological mutants of garlic

    Choudhary, A.D.; Dnyansagar, V.R. (Nagpur Univ. (India). Dept. of Botany)

    1982-01-01

    Cloves of garlic (Allium sativuum Linn.) were exposed to gamma rays with various doses and different concentrations of ethylmethane sulphonate (EMS), diethyl sulphate (dES) and ethylene imine (EI). In the second and third generations, 16 types of morphological mutants were recorded with varied frequencies. Of all the mutagens used, gamma rays were found to be the most effective in inducing the maximum number of mutations followed EI, EMS and dES in that order.

  7. Morphological mutants of garlic

    Cloves of garlic (Allium sativuum Linn.) were exposed to gamma rays with various doses and different concentrations of ethylmethane sulphonate (EMS), diethyl sulphate (dES) and ethylene imine (EI). In the second and third generations, 16 types of morphological mutants were recorded with varied frequencies. Of all the mutagens used, gamma rays were found to be the most effective in inducing the maximum number of mutations followed EI, EMS and dES in that order. (author)

  8. Irradiation of mutants of rose

    Radiation-induced Reddish-orange (R) and Pink (P) flowered mutants of the rose cultivar Montezuma were subjected to a second treatment of gamma radiation. Effects of this treatment were recorded on bud-take, growth, survival, flowering and essential oil content. The P mutant was more radiosensitive than the R mutant. The occurrence of certain early flowering and flower yielding plants in the latter mutant proved the efficiency of this technique for inducing genetic variability in garden roses. (author)

  9. High Persister Mutants in Mycobacterium tuberculosis

    Torrey, Heather L.; Keren, Iris; Via, Laura E.; Lee, Jong Seok; Lewis, Kim

    2016-01-01

    Mycobacterium tuberculosis forms drug-tolerant persister cells that are the probable cause of its recalcitrance to antibiotic therapy. While genetically identical to the rest of the population, persisters are dormant, which protects them from killing by bactericidal antibiotics. The mechanism of persister formation in M. tuberculosis is not well understood. In this study, we selected for high persister (hip) mutants and characterized them by whole genome sequencing and transcriptome analysis. In parallel, we identified and characterized clinical isolates that naturally produce high levels of persisters. We compared the hip mutants obtained in vitro with clinical isolates to identify candidate persister genes. Genes involved in lipid biosynthesis, carbon metabolism, toxin-antitoxin systems, and transcriptional regulators were among those identified. We also found that clinical hip isolates exhibited greater ex vivo survival than the low persister isolates. Our data suggest that M. tuberculosis persister formation involves multiple pathways, and hip mutants may contribute to the recalcitrance of the infection. PMID:27176494

  10. Characterization of Glutamine-Requiring Mutants of Pseudomonas aeruginosa

    Janssen, Dick B.; Joosten, Han M.L.J.; Herst, Patricia M.; Drift, Chris van der

    1982-01-01

    Revertants were isolated from a glutamine-requiring mutant of Pseudomonas aeruginosa PAO. One strain showed thermosensitive glutamine requirement and formed thermolabile glutamine synthetase, suggesting the presence of a mutation in the structural gene for glutamine synthetase. The mutation conferri

  11. [Pigment composition and photosynthetic activity of pea chlorophyll mutants].

    Ladygin, V G

    2003-01-01

    Pea chlorophyll mutants chlorotica 2004 and 2014 have been studied. The mutants differ from the initial form (pea cultivar Torsdag) in stem and leaf color (light green in the mutant 2004 and yellow-green in the mutant 2014), relative chlorophyll content (approximately 80 and 50%, respectively), and the composition of carotenoids: the mutant 2004 contains a significantly smaller amount of carotene but accumulates more lutein and violaxanthine; in the mutant 2014, the contents of all carotenoids are decreased proportionally to the decrease in chlorophyll content. It is shown that the rates of CO2 assimilation and oxygen production in the mutant chlorotica 2004 and 2014 plants are reduced. The quantum efficiency of photosynthesis in the mutants is 29-30% lower than in the control plants; in their hybrids, however, it is 1.5-2 higher. It is proposed that both the greater role of dark respiration in gas exchange and the reduced photosynthetic activity in chlorotica mutants are responsible for the decreased phytomass increment in these plants. On the basis of these results, the conclusion is drawn that the mutations chlorotica 2004 and 2014 affect the genes controlling the formation and functioning of various components of the photosynthetic apparatus. PMID:12942751

  12. Photorepair mutants of Arabidopsis

    UV radiation induces two major DNA damage products, the cyclobutane pyrimidine dimer (CPD) and, at a lower frequency, the pyrimidine (6-4) pyrimidinone dimer (6-4 product). Although Escherichia coli and Saccharomyces cerevisiae produce a CPD-specific photolyase that eliminates only this class of dimer, Arabidopsis thaliana, Drosophila melanogaster, Crotalus atrox, and Xenopus laevis have recently been shown to photoreactivate both CPDs and 6-4 products. We describe the isolation and characterization of two new classes of mutants of Arabidopsis, termed uvr2 and uvr3, that are defective in the photoreactivation of CPDs and 6-4 products, respectively. We demonstrate that the CPD photolyase mutation is genetically linked to a DNA sequence encoding a type II (metazoan) CPD photolyase. In addition, we are able to generate plants in which only CPDs or 6-4 products are photoreactivated in the nuclear genome by exposing these mutants to UV light and then allowing them to repair one or the other class of dimers. This provides us with a unique opportunity to study the biological consequences of each of these two major UV-induced photoproducts in an intact living system

  13. Fibrinolytic Activity of Recombinant Mutant Streptokinase

    Mahboobeh Mobarrez

    2015-04-01

    Full Text Available Background: Streptokinase is a bacterial protein produced by different beta hemolytic streptococci and widely used in thrombolytic treatment. The main disadvantage of using streptokinase is antibody formation which causes allergic reaction to neutralize effects of streptokinase therapy. Aim of this study was investigate of recombinant mutant streptokinase fibrinolytic activity.Materials and Methods: In this study recombinant mutant streptokinase without 42 amino acids from the C terminal region was purified by affinity S-Tag column chromatography and its fibrinolytic activity was studied.Results: The concentration of expressed and purified protein was 10 mg/ml. Its enzyme activity was assayed using zymography, radial caseinolytic activity and fibrin plate test methods and estimated quantitatively by casein digestion method compared to a commercial form.Conclusion: It was found that this product had the more volume and more enzymatic activity.

  14. Cloning, preparation and preliminary crystallographic studies of penicillin V acylase autoproteolytic processing mutants

    The production, crystallization and characterization of three inactive mutants of penicillin V acylase from B. sphaericus in their respective precursor and processed forms are reported. The space groups are different for the native enzyme and the mutants. The crystallization of three catalytically inactive mutants of penicillin V acylase (PVA) from Bacillus sphaericus in precursor and processed forms is reported. The mutant proteins crystallize in different primitive monoclinic space groups that are distinct from the crystal forms for the native enzyme. Directed mutants and clone constructs were designed to study the post-translational autoproteolytic processing of PVA. The catalytically inactive mutants will provide three-dimensional structures of precursor PVA forms, plus open a route to the study of enzyme–substrate complexes for this industrially important enzyme

  15. The Swedish mutant barley collection

    Full text: The Swedish mutation research programme in barley began about 50 years ago and has mainly been carried out at Svaloev in co-operation with the institute of Genetics at the University of Lund. The collection has been produced from different Swedish high-yielding spring barley varieties, using the following mutagens: X-rays, neutrons, several organic chemical compounds such as ethyleneimine, several sulfonate derivatives and the inorganic chemical mutagen sodium azide. Nearly 10,000 barley mutants are stored in the Nordic Gene Bank and documented in databases developed by Udda Lundquist, Svaloev AB. The collection consists of the following nine categories with 94 different types of mutants: 1. Mutants with changes in the spike and spikelets; 2. Changes in culm length and culm composition; 3. Changes in growth types; 4. Physiological mutants; 5. Changes in awns; 6. Changes in seed size and shape; 7. Changes in leaf blades; 8. Changes in anthocyanin and colour; 9. Resistance to barley powdery mildew. Barley is one of the most thoroughly investigated crops in terms of induction of mutations and mutation genetics. So far, about half of the mutants stored at the Nordic Gene Bank, have been analysed genetically; They constitute, however, only a minority of the 94 different mutant types. The genetic analyses have given valuable insights into the mutation process but also into the genetic architecture of various characters. A number of mutants of two-row barley have been registered and commercially released. One of the earliest released, Mari, an early maturing, daylength neutral, straw stiff mutant, is still grown in Iceland. The Swedish mutation material has been used in Sweden, but also in other countries, such as Denmark, Germany, and USA, for various studies providing a better understanding of the barley genome. The collection will be immensely valuable for future molecular genetical analyses of clone mutant genes. (author)

  16. Genetics of Ustilago violacea. I. Carotenoid mutants and carotenogenesis

    Wild-type strains of Ustilago violacea produce pink colonies on laboratory medium and yield white, orange, pumpkin, and yellow colonies after uv mutagenesis. The wild-type strains contain neurosporene and lycopene; one orange mutant, γ-carotene; and one yellow mutant, β-carotene. One white mutant had no detectable carotenoids. Diploid colonies heterozygous for wild type and orange, pumpkin, yellow, or white are phenotypically wild type. Diploid colonies heterozygous for yellow and orange are also phenotypically wild type. Diploid colonies heterozygous for white and orange; white and yellow; and white, yellow, and orange are phenotypically light orange, light yellow, and orange-yellow, respectively. The white mutants give a circular complementation map; the color mutants fit a linear complementation map. We propose a multienzyme of four identical dehydrogenases and one or two identical cyclases for carotenogenesis in this species. The white and color mutants represent structural mutations altering the conformation of the dehydrogenase or cyclase, respectively. Furthermore, cyclases may or may not aggregate in association with the dehydrogenase aggregate to form the multienzyme aggregate responsible for the color mutants

  17. Mutants of alfalfa mosaic virus

    In this thesis the isolation and characterization of a number of mutants of alfalfa mosaic virus, a plant virus with a coat protein dependent genome, is described. Thermo-sensitive (ts) mutants were selected since, at least theoretically, ts mutations can be present in all virus coded functions. It was found that a high percentage of spontaneous mutants, isolated because of their aberrant symptoms, were ts. The majority of these isolates could grow at the non-permissive temperature in the presence of a single wild type (wt) component. To increase the mutation rate virus preparations were treated with several mutagens. After nitrous acid treatment or irradiation with ultraviolet light, an increase in the level of mutations was observed. UV irradiation was preferred since it did not require large amounts of purified viral components. During the preliminary characterization of potential ts mutants the author also obtained one structural and several symptom mutants which were analysed further (chapter 7, 8 and 9). The properties of the ts mutants are described in chapter 3-7. (Auth.)

  18. Root hair mutants of barley

    Barley mutants without root hairs or with short or reduced root hairs were isolated among M2 seeds of 'Lux' barley (Hordeum vulgare L.) after acidified sodium azide mutagenesis. Root hair mutants are investigated intensively in Arabidopsis where about 40 genes are known. A few root hair mutants are known in maize, rice, barley and tomato. Many plants without root hairs grow quite well with good plant nutrition, and mutants have been used for investigations of uptake of strongly bound nutrients like phosphorus, iron, zinc and silicon. Seed of 'Lux' barley (Sejet Plant Breeding, Denmark) were soaked overnight, and then treated with 1.5-millimolarsodium azide in 0.1 molar sodium phosphate buffer, pH 3, for 2.5 hours according to the IAEA Manual on Mutation Breeding (2nd Ed.). After rinsing in tap water and air-drying, the M2 seeds were sown in the field the same day. Spikes, 4-6 per M1 plant, were harvested. The mutation frequency was similar to that obtained with other barley cultivars from which low-phytate mutants were isolated [5]. Seeds were germinated on black filter paper in tap water for 3 or 4 days before scoring for root hair mutants

  19. Structures of Pseudomonas aeruginosa β-ketoacyl-(acyl-carrier-protein) synthase II (FabF) and a C164Q mutant provide templates for antibacterial drug discovery and identify a buried potassium ion and a ligand-binding site that is an artefact of the crystal form

    Three crystal structures of recombinant P. aeruginosa FabF are reported: the apoenzyme, an active-site mutant and a complex with a fragment of a natural product inhibitor. The characterization provides reagents and new information to support antibacterial drug discovery. Bacterial infections remain a serious health concern, in particular causing life-threatening infections of hospitalized and immunocompromised patients. The situation is exacerbated by the rise in antibacterial drug resistance, and new treatments are urgently sought. In this endeavour, accurate structures of molecular targets can support early-stage drug discovery. Here, crystal structures, in three distinct forms, of recombinant Pseudomonas aeruginosa β-ketoacyl-(acyl-carrier-protein) synthase II (FabF) are presented. This enzyme, which is involved in fatty-acid biosynthesis, has been validated by genetic and chemical means as an antibiotic target in Gram-positive bacteria and represents a potential target in Gram-negative bacteria. The structures of apo FabF, of a C164Q mutant in which the binding site is altered to resemble the substrate-bound state and of a complex with 3-(benzoylamino)-2-hydroxybenzoic acid are reported. This compound mimics aspects of a known natural product inhibitor, platensimycin, and surprisingly was observed binding outside the active site, interacting with a symmetry-related molecule. An unusual feature is a completely buried potassium-binding site that was identified in all three structures. Comparisons suggest that this may represent a conserved structural feature of FabF relevant to fold stability. The new structures provide templates for structure-based ligand design and, together with the protocols and reagents, may underpin a target-based drug-discovery project for urgently needed antibacterials

  20. Structures of Pseudomonas aeruginosa β-ketoacyl-(acyl-carrier-protein) synthase II (FabF) and a C164Q mutant provide templates for antibacterial drug discovery and identify a buried potassium ion and a ligand-binding site that is an artefact of the crystal form

    Baum, Bernhard [Johannes Gutenberg-Universität, Staudinger Weg 5, 55128 Mainz (Germany); Lecker, Laura S. M.; Zoltner, Martin [University of Dundee, Dundee DD1 4EH, Scotland (United Kingdom); Jaenicke, Elmar [Johannes Gutenberg-Universität, Jakob Welder Weg 26, 55128 Mainz (Germany); Schnell, Robert [Karolinska Institutet, 17 177 Stockholm (Sweden); Hunter, William N., E-mail: w.n.hunter@dundee.ac.uk [University of Dundee, Dundee DD1 4EH, Scotland (United Kingdom); Brenk, Ruth, E-mail: w.n.hunter@dundee.ac.uk [Johannes Gutenberg-Universität, Staudinger Weg 5, 55128 Mainz (Germany)

    2015-07-28

    Three crystal structures of recombinant P. aeruginosa FabF are reported: the apoenzyme, an active-site mutant and a complex with a fragment of a natural product inhibitor. The characterization provides reagents and new information to support antibacterial drug discovery. Bacterial infections remain a serious health concern, in particular causing life-threatening infections of hospitalized and immunocompromised patients. The situation is exacerbated by the rise in antibacterial drug resistance, and new treatments are urgently sought. In this endeavour, accurate structures of molecular targets can support early-stage drug discovery. Here, crystal structures, in three distinct forms, of recombinant Pseudomonas aeruginosa β-ketoacyl-(acyl-carrier-protein) synthase II (FabF) are presented. This enzyme, which is involved in fatty-acid biosynthesis, has been validated by genetic and chemical means as an antibiotic target in Gram-positive bacteria and represents a potential target in Gram-negative bacteria. The structures of apo FabF, of a C164Q mutant in which the binding site is altered to resemble the substrate-bound state and of a complex with 3-(benzoylamino)-2-hydroxybenzoic acid are reported. This compound mimics aspects of a known natural product inhibitor, platensimycin, and surprisingly was observed binding outside the active site, interacting with a symmetry-related molecule. An unusual feature is a completely buried potassium-binding site that was identified in all three structures. Comparisons suggest that this may represent a conserved structural feature of FabF relevant to fold stability. The new structures provide templates for structure-based ligand design and, together with the protocols and reagents, may underpin a target-based drug-discovery project for urgently needed antibacterials.

  1. Regioselective alkane hydroxylation with a mutant AlkB enzyme

    Koch, Daniel J.; Arnold, Frances H.

    2012-11-13

    AlkB from Pseudomonas putida was engineered using in-vivo directed evolution to hydroxylate small chain alkanes. Mutant AlkB-BMO1 hydroxylates propane and butane at the terminal carbon at a rate greater than the wild-type to form 1-propanol and 1-butanol, respectively. Mutant AlkB-BMO2 similarly hydroxylates propane and butane at the terminal carbon at a rate greater than the wild-type to form 1-propanol and 1-butanol, respectively. These biocatalysts are highly active for small chain alkane substrates and their regioselectivity is retained in whole-cell biotransformations.

  2. Agronomic performance of rape seed (brassica napus L.) mutant lines under drought conditions

    Oil seed forms of Brassica napus are not well adapted to drought and the warner environments of Pakistan. Induced mutations were, therefore, utilized for improving drought tolerance efficiency of two napus cultivars. Induction of genetic variability, selection of desirable mutants and stabilization of mutants in acceptable agronomic background were carried out during 1988-1991. Fourteen promising mutants each of cv. Pak-cheen and Tower were evaluated for different agronomic characters in separate yield trials, under extremely drought conditions. The results demonstrated that yield potential of some mutants was very high and 9 mutants of cv. Pak-cheen and 8 mutants of cv. Tower significantly (P<0.05) out yield the local commercial cultivar. Eleven mutants in both the trials matured significantly earlier than the check. Nevertheless, more extensive testing of the drought tolerant lines under diversified environs of the country will help confirm these findings. (author)

  3. Mutant Varieties of Crop Plants

    Since 1969, the Joint PAO/IAEA Division undertakes to collect and publish information on varieties of crop plants that were developed directly from induced mutants or by using mutants in cross breeding (Micke 1972 and Sigurbjörnsson and Micke (1969, 1974). The purpose of this undertaking is to assess realistically the potential of induced mutation techniques to contribute towards progress in plant breeding. Varieties which have successfully passed official trials and were approved or recommended by national governmental authorities for cultivation, appear to be good indicators of practical success. By 1 October 1978, we know about 195 of such varieties in agricultural crop plants). They belong to 37 different plant species and come from 30 different countries. In addition, there are more than 120 mutant cultivars of ornamental plants known, which represent a considerable economic value for countries with developed horticulture (Broertjes and van Harten 1978)

  4. Teaching Form as Form

    Keiding, Tina Bering

    2012-01-01

    understanding of form per se, or, to use an expression from this text, of form as form. This challenge can be reduced to one question: how can design teaching support students in achieving not only the ability to recognize and describe different form-related concepts in existing design (i.e. analytical and...

  5. Gamma ray induced male sterility mutant in lentil

    Full text: Male sterility refers to the failure of pollen grains to bring about effective fertilization, either due to structural default or physiological disfunctioning and has special significance in hybridization programmes. Male steriles have been produced in a number of crop plants like red gram, pigeon pea, mung bean, khesari and lentil. A completely male sterile mutant was isolated in Lens culinaris Medik, after seed treatment with 100 Gy dose of gamma rays. The male sterile mutant showed 100% pollen sterility but was morphologically more vigorous than the parent plants. It showed more branches and its leaves were bigger, more oblong and dark green. The number of flowers borne by the mutant was significantly higher than any other plant of the treatment. The size of the flowers was also increased but the anthers were smaller in size. Pollen grains were few in number, round in shape but empty and did not take up any stain, indicating that normal microsporogenesis had not taken place. This male sterile mutant was used as the female parent and pollinated with pollen of a parent. Four pods with one seed in each were formed indicating that the mutant was female fertile. The seeds were smaller than those of the parent variety and also dark coloured. The mutant showed increased vigour and flower number as compared to parental plants. Lentil is an important pulse crop and induction of variability in its germplasm is necessary for its improvement. Male steriles can be used conveniently in lentil hybridization programmes. (author)

  6. Assessment of gamma ray induced advance generation mutants of short grain aromatic non-Basmati rice

    Agronomic worth of 18 gamma ray induced mutants in M4 generation was assessed along with their two mother genotypes (Pigmented mutant and IET 13541), having the genetic background of Gobindabhog, a short grain aromatic non-Basmati rice cultivar, popularly grown in southern parts of West Bengal. The mutants showed considerable amount of genetic variability for different agronomic characters. Majority of the mutants had combination of both positive and negative forms of important yield contributing characters. Performance of three mutants (G1m3, G2m4 and G2m9) indicated considerable improvement in grain yield over their respective control. The increased grain yield per plant in above mutants is primarily due to increase in panicle number per plant, spikelet number per panicle, grain number per panicle and test weight. These high yielding multilocational mutants need further testing in multilocation trials for evaluation of their potential for direct release as varieties of short grain aromatic rice. The other mutants may be used in cross breeding programmes of aromatic rice for utilization of agronomically useful mutant characters viz., earlier flowering, short plant stature, erect flag leaf, higher grain number, more test weight and others. The apparent changes for different characters in individual mutant may not be due to genetic changes in all the affected characters. The possible role of pleiotropic effects of mutant gene cannot be ruled out. (author)

  7. Selection and properties of Escherichia coli mutants defective in the synthesis of cyclopropane fatty acids.

    Taylor, F; Cronan, J E

    1976-01-01

    Mutants of Escherichia coli K-12 defective in the synthesis of cyclopropane fatty acids (CFA) have been selected and isolated by a L-[methyl-3H]methionine suicide procedure. Two mutants were isolated. Stationary-phase cultures of both mutants contain less than 0.7% of the CFA content found in the parental strain. The CFA deficiency is attributed to a deficiency of CFA synthetase activity. Extracts of both mutants contain less than 10% of the CFA synthetase activity found in extracts of the parental strain. Experiments in which parental and mutant extracts were mixed indicate that the lack of activity in the mutant strains is not due to an inhibitor of CFA synthetase present in the mutant extracts. We have not yet detected a physiological phenotype for these mutants. These strains grow normally at various temperatures in a variety of media. We have tested survival (colony-forming ability) in response to (i) prolonged incubation in stationary phase, (ii) exposure to drying, and (iii) exposure to detergents, heavy metals, low pH, high salt concentration, and a variety of other environmental conditions. The survival of both mutants is identical to that of the parental strain under all conditions tested. The compositions (excepting the CFA deficiency) and metabolic turnover rates of the phospholipids of both mutant strains are indistinguishable from those of the wild-type strain. The transport of several amino acids also seems normal in these mutants. PMID:1107324

  8. Wild Accessions and Mutant Resources

    Kawaguchi, Masayoshi; Sandal, Niels Nørgaard

    2014-01-01

    Lotus japonicus, Lotus burttii, and Lotus filicaulis are species of Lotus genus that are utilized for molecular genetic analysis such as the construction of a linkage map and QTL analysis. Among them, a number of mutants have been isolated from two wild accessions: L. japonicus Gifu B-129 and Miy...

  9. Plant cultivars derived from mutation induction or the use of induced mutants in cross breeding

    Since 1969 we have collected information on cultivated varieties of plants, developed by using induced mutations. Whenever we learn about a cultivar presumably derived from an induced mutant or from use of mutants in crosses. we mail a questionnaire to the breeder. The information gathered in this way is stored in our file on ''Mutant Varieties''. Excerpts are published regularly in the form of a list in the FAO/IAEA Mutation Breeding Newsletter. Our mutant variety list has repeatedly provided a basis for analyses on the value and prospects of mutation breeding

  10. Induced High Lysine Mutants in Barley

    Doll, Hans; Køie, B.; Eggum, B. O.

    1974-01-01

    Screening of mutagenically treated materials by combined Kjeldahl nitrogen and dye-binding capacity determinations disclosed fourteen barley mutants, which have from a few to about 40 per cent more lysine in the protein and one mutant with 10 per cent less lysine in the protein than the parent...... variety. Comparisons of six high lysine mutants with the parent variety showed that grain yield and seed size of the mutants are reduced between 10 and 30 per cent. However, the most promising mutant had the lowest reduction in grain yield, and the absolute lysine yield of this mutant was some 30 per cent...... above that of the parent variety. Feeding tests with rats revealed substantial increases in the biological value of the high lysine mutant protein. Also the net protein utilization was improved but less so because of a somewhat reduced digestibility of the mutant protein....

  11. Yeast mutants auxotrophic for choline or ethanolamine.

    Atkinson, K D; Jensen, B.; Kolat, A I; Storm, E M; Henry, S. A.; Fogel, S

    1980-01-01

    Three mutants of the yeast Saccharomyces cerevisiae which require exogenous ethanolamine or choline were isolated. The mutants map to a single locus (cho1) on chromosome V. The lipid composition suggests that cho1 mutants do not synthesize phosphatidylserine under any growth conditions. If phosphatidylethanolamine or phosphatidylcholine, which are usually derived from phosphatidylserine, were synthesized from exogenous ethanolamine or choline, the mutants grew and divided relatively normally....

  12. An extra early mutant of pigeonpea

    The redgram (Cajanus cajan (L.) Huth) variety 'Prabhat DT' was gamma irradiated with 100, 200, 300 and 400 Gy doses. Several mutants have been identified viz., extra early mutants, monostem mutants, obcordifoliate mutants and bi-stigmatic mutants. The extra early mutant was obtained when treated with 100 Gy dose. The mutant was selfed and forwarded from M2 to M4 generation. In the M4 generation the mutant line was raised along with the parental variety. Normal cultural practices were followed and the biometrical observations were recorded. It was observed that for the characters viz., total number of branches per plant, number of pods per plants, seeds per pod, 100 seed weight and seed yield per plant there was no difference between the mutant and parent variety. Whereas, regarding the days to flowering and maturity the mutants were earlier than the parents. The observation was recorded from two hundred plants each. The mutant gives the same yield in 90 days as that of the parent variety in 107 days, which make it an economic mutant

  13. Problem-Solving Test: Tryptophan Operon Mutants

    Szeberenyi, Jozsef

    2010-01-01

    This paper presents a problem-solving test that deals with the regulation of the "trp" operon of "Escherichia coli." Two mutants of this operon are described: in mutant A, the operator region of the operon carries a point mutation so that it is unable to carry out its function; mutant B expresses a "trp" repressor protein unable to bind…

  14. Studies on mutant breeding of Hibiscus syriacus

    Song, Hi Sup; Kim, Jin Kyu; Lee, Ki Un; Kim, Young Taik

    1997-01-01

    Hibiscus has been known as a national flower of Korea. Hibiscus has such a characteristic of self-incompatibility that all the plant exist as natural hybrids and have heterogeneous genes. Many domestic 91 varieties of Hibiscus syriacus were collected. Radiosensitivity of H. Syriacus irradiated with {gamma}-ray was investigated in plant cuttings. The plant height was reduced by 45% in 5KR irradiated group, compared to control group. The radiation dose of 5KR could be recommended for mutation breeding of Hibiscus cuttings. Radiosensitivity of {gamma}-ray irradiated Hibiscus seed were investigated. The germination rate, survival rate and plant height was better in the 4KR irradiation plot than control. The radiation dose of 10{approx}12KR are recommended for mutation breeding of Hibiscus. Promising mutant lines were selected form the varieties of Hwarang, Wolsan no. 176, Ilpyondansim, Emille, Hanol, Yongkwang, Saeyongkwang, Chungmu, Imjinhong, Arang, Hungdansim-1 and Hongdansim-2. (author). 66 refs., 16 tabs., 13 figs.

  15. Studies on mutant breeding of Hibiscus syriacus

    Hibiscus has been known as a national flower of Korea. Hibiscus has such a characteristic of self-incompatibility that all the plant exist as natural hybrids and have heterogeneous genes. Many domestic 91 varieties of Hibiscus syriacus were collected. Radiosensitivity of H. Syriacus irradiated with γ-ray was investigated in plant cuttings. The plant height was reduced by 45% in 5KR irradiated group, compared to control group. The radiation dose of 5KR could be recommended for mutation breeding of Hibiscus cuttings. Radiosensitivity of γ-ray irradiated Hibiscus seed were investigated. The germination rate, survival rate and plant height was better in the 4KR irradiation plot than control. The radiation dose of 10∼12KR are recommended for mutation breeding of Hibiscus. Promising mutant lines were selected form the varieties of Hwarang, Wolsan no. 176, Ilpyondansim, Emille, Hanol, Yongkwang, Saeyongkwang, Chungmu, Imjinhong, Arang, Hungdansim-1 and Hongdansim-2. (author). 66 refs., 16 tabs., 13 figs

  16. Mutant of Japanese pear resistant to Black Spot Disease

    Full text: Nijisseike is one of the leading cultivars of Japanese pear (Pyrus serotinea Rehd.), but susceptible to black spot disease. Farmers try to prevent this disease by wrapping the fruit with a paper bag and by repeated spraying of fungicides. The disease is caused by a Japanese pear pathotype of Alternaria alternata (Fr.) Keissler. Susceptibility is controlled by a single dominant gene. In 1962, grafted trees of this cultivar were planted at a distance between 53 and 93 m from the 60Co source in the gamma-field (daily dose 15-4 rad). One branch on a tree planted at 53 m was detected as resistant in 1981. Under field conditions, black spots were observed on many fruits and leaves of the original trees by natural infection in early July, however, they were not observed on the mutant. To examine the resistance of the mutant, artificial inoculations were made using spores of the pathogen and the host specific toxin produced by germinating spores. When some drops of the spore suspension are placed on leaves, the formation of black spots depends upon the leaf age. In a resistant cv. as Chojuro, black spot symptoms are formed only when inoculated on young leaves. An intermediate reaction was observed in the mutant, whereas the original Nijisseiki showed severe symptoms. When inoculation was made on matured fruit skins, no black spot was formed on the mutant just like on the resistant cv. Chojuro, while many small black spots were formed and grew into large spots overlapping each other on the susceptible cv. Nijisseiki. In case of the crude toxin inoculation (4-0.04 ppm) of cv. Nijisseiki black spots were formed on the surface of the susceptible fruit skin, and necrotic lesions at the cut end of detached small pieces of leaves, although reaction on fruit skins was weaker compared with inoculation by spores. However, no symptoms were observed from the toxin application on the mutant and the resistant cv. Chojuro. That the resistance of the mutant is classified as

  17. Mutant connexin 50 (S276F) inhibits channel and hemichannel functions inducing cataract

    Yuanyuan Liu; Chen Qiao; Tanwei Wei; Fang Zheng; Shuren Guo; Qiang Chen; Ming Yan; Xin Zhou

    2015-06-01

    This study was designed to detect the expression, detergent resistance, subcellular localization, and channel and hemichannel functions of mutant Cx50 to understand the forming mechanism for inducing congenital cataract by a novel mutation p.S276F in connexin 50 (Cx50) reported previously by us. HeLa and human lens epithelial (HLE) cells were transfected with wild-type Cx50 and mutant Cx50 (S276F). We examined the functional characteristics of mutant Cx50 (S276F) in comparison with those of wild-type Cx50 using immunoblot, confocal fluorescence microscopy, dye transfer analysis and dye uptake assay. The mutant and wild-type Cx50 were expressed in equal levels and could efficiently localize to the plasma membrane without transportation and assembly problems. Scrape loading dye transfer was significantly evident in cells transfected with wild-type Cx50 compared to those in cells transfected with mutant Cx50 and cotransfected with wild-type and mutant Cx50. The dye uptake was found to be significantly lower in cells transfected with mutant Cx50 than in cells transfected with wild-type Cx50 and cells cotransfected with wild-type and mutant Cx50. The transfected HeLa and HLE cell lines showed similar performance in all the experiments. These results indicated that the mutant Cx50 (S276F) might inhibit the function of gap junction channel in a dominant negative manner, but inhibit the hemichannel function in a recessive negative manner.

  18. Natural and artificial mutants as valuable resources for functional genomics and molecular breeding

    Shu-Ye Jiang, Srinivasan Ramachandran

    2010-01-01

    Full Text Available With the completion of rice genome sequencing, large collection of expression data and the great efforts in annotating rice genomes, the next challenge is to systematically assign functions to all predicted genes in the genome. The generations and collections of mutants at the genome-wide level form technological platform of functional genomics. In this study, we have reviewed currently employed tools to generate such mutant populations. These tools include natural, physical, chemical, tissue culture, T-DNA, transposon or gene silencing based mutagenesis. We also reviewed how these tools were used to generate a large collection of mutants and how these mutants can be screened and detected for functional analysis of a gene. The data suggested that the current population of mutants might be large enough to tag all predicted genes. However, the collection of flanking sequencing tags (FSTs is limited due to the relatively higher cost. Thus, we have proposed a new strategy to generate gene-silencing mutants at the genome-wide level. Due to the large collection of insertion mutants, the next step to rice functional genomics should be focusing on functional characterization of tagged genes by detailed survey of corresponding mutants. Additionally, we also evaluated the utilization of these mutants as valuable resources for molecular breeding.

  19. PNRI mutant variety: Cordyline 'Afable'

    Cordyline 'Afable', registered by the Philippine Nuclear Research Institute as NSIC 2009 Or-83, is an induced mutant developed from Cordyline 'Kiwi' by treating stem cuttings with acute gamma radiation from a Cobalt-60 source. The new mutant is identical to Cordyline 'Kiwi' in growth habit but differs in foliage color, and exhibits field resistance to Phytophthora sp., a fungus that causes leaf blight and rot in Ti plants. Results of this mutation breeding experiment showed that leaf color was altered by gamma irradiation and resistance to fungal diseases was improved. It also demonstrated how mutations that occur in nature may be generated artificially. Propagation of cordyline 'Afable' is true-to-type by vegetative propagation methods, such as separation of suckers and offshoots, shoot tip cutting, and top cutting. Aside from landscaping material, terrarium or dish-garden plant, it is ideal as containerized plant for indoor and outdoor use. The leaves or shoots may be harvested as cut foliage for flower arrangements. (author)

  20. Gamma ray induced mutants in Coleus

    The germplasm collection of Chinese potato (Coleus parviflorus Benth) contains almost no variation for yield contributing traits. The crop does not produce seeds. Treatment of underground tubers with 1 kR, 2 kR, 3 kR and 4 kR gamma rays resulted in 50 morphologically different mutants which are maintained as mutant clones. In the M1V1 generation, suspected mutant sprouts, were carefully removed and grown separately. The most interesting mutant types are the following: (i) erect mutant with spoon shaped light green leaves, 30 cm long inflorescences against 20 cm in the control, cylindrical tubers measuring ca. 7.0 cm long and 3 cm girth against 4 cm and 2.5 cm in the control (ii) early mutants 1 and 2, one having less leaf serration, the other having light green small leaves and dwarf type (iii) fleshy leaf mutant, dark green, thick and smooth leaves. Control plants spread almost in 1 m2 area and bear tubers from the nodes of branches. In the early mutants tuber formation is mainly restricted to the base of the plant, which makes harvest easier. The crop usually matures within 150 - 160 days, the early mutants are ready for harvest 100 days after planting. As the mutants are less spreading, the yield could be increased by closer spacing

  1. Nanoformulated cell-penetrating survivin mutant and its dual actions

    Sriramoju B

    2014-07-01

    Full Text Available Bhasker Sriramoju, Rupinder K Kanwar, Jagat R Kanwar Nanomedicine Laboratory of Immunology and Molecular Biomedical Research (NLIMBR, School of Medicine, Faculty of Health, Deakin University, Geelong, Australia Abstract: In this study, we investigated the differential actions of a dominant-negative survivin mutant (SurR9-C84A against cancerous SK-N-SH neuroblastoma cell lines and differentiated SK-N-SH neurons. In both the cases, the mutant protein displayed dual actions, where its effects were cytotoxic toward cancerous cells and proliferative toward the differentiated neurons. This can be explained by the fact that tumorous (undifferentiated SK-N-SH cells have a high endogenous survivin pool and upon treatment with mutant SuR9-C84A causes forceful survivin expression. These events significantly lowered the microtubule dynamics and stability, eventually leading to apoptosis. In the case of differentiated SK-N-SH neurons that express negligible levels of wild-type survivin, the mutant indistinguishably behaved in a wild-type fashion. It also favored cell-cycle progression, forming the chromosome-passenger complex, and stabilized the microtubule-organizing center. Therefore, mutant SurR9-C84A represents a novel therapeutic with its dual actions (cytotoxic toward tumor cells and protective and proliferative toward neuronal cells, and hence finds potential applications against a variety of neurological disorders. In this study, we also developed a novel poly(lactic-co-glycolic acid nanoparticulate formulation to surmount the hurdles associated with the delivery of SurR9-C84A, thus enhancing its effective therapeutic outcome. Keywords: survivin mutant, neurological disorders, protein therapeutics, inhibitor of apoptosis protein family, poly(lactic-co-glycolic acid

  2. Factors contributing to the biofilm-deficient phenotype of Staphylococcus aureus sarA mutants.

    Laura H Tsang

    Full Text Available Mutation of sarA in Staphylococcus aureus results in a reduced capacity to form a biofilm, but the mechanistic basis for this remains unknown. Previous transcriptional profiling experiments identified a number of genes that are differentially expressed both in a biofilm and in a sarA mutant. This included genes involved in acid tolerance and the production of nucleolytic and proteolytic exoenzymes. Based on this we generated mutations in alsSD, nuc and sspA in the S. aureus clinical isolate UAMS-1 and its isogenic sarA mutant and assessed the impact on biofilm formation. Because expression of alsSD was increased in a biofilm but decreased in a sarA mutant, we also generated a plasmid construct that allowed expression of alsSD in a sarA mutant. Mutation of alsSD limited biofilm formation, but not to the degree observed with the corresponding sarA mutant, and restoration of alsSD expression did not restore the ability to form a biofilm. In contrast, concomitant mutation of sarA and nuc significantly enhanced biofilm formation by comparison to the sarA mutant. Although mutation of sspA had no significant impact on the ability of a sarA mutant to form a biofilm, a combination of protease inhibitors (E-64, 1-10-phenanthroline, and dichloroisocoumarin that was shown to inhibit the production of multiple extracellular proteases without inhibiting growth was also shown to enhance the ability of a sarA mutant to form a biofilm. This effect was evident only when all three inhibitors were used concurrently. This suggests that the reduced capacity of a sarA mutant to form a biofilm involves extracellular proteases of all three classes (serine, cysteine and metalloproteases. Inclusion of protease inhibitors also enhanced biofilm formation in a sarA/nuc mutant, with the combined effect of mutating nuc and adding protease inhibitors resulting in a level of biofilm formation with the sarA mutant that approached that of the UAMS-1 parent strain. These results

  3. Rice mutant cultivar SCS114 Andosan

    The development process and its yield, quality performance of the mutant rice variety SCS Andosan 114 was described. SCS Andosan 114 was selected from the mutant progeny of IR 841 after treatment of 150 Gy gamma rays; It had a 7.4 ∼ 9.6% yield increase over IR 841 and a higher amylase content (28%) than IR 841 (19%). The mutant variety also showed high tolerance to iron toxicity and resistance to blast disease. (author)

  4. Regulation of Mutant p53 Protein Expression

    Vijayakumaran, Reshma; Tan, Kah Hin; Miranda, Panimaya Jeffreena; Haupt, Sue; Haupt, Ygal

    2015-01-01

    For several decades, p53 has been detected in cancer biopsies by virtue of its high protein expression level which is considered indicative of mutation. Surprisingly, however, mouse genetic studies revealed that mutant p53 is inherently labile, similar to its wild type (wt) counterpart. Consistently, in response to stress conditions, both wt and mutant p53 accumulate in cells. While wt p53 returns to basal level following recovery from stress, mutant p53 remains stable. In part, this can be e...

  5. Characterization of Sugar Insensitive (sis) Mutants of Arabidopsis

    Gibson, Susan I.

    2009-06-08

    Despite the fact that soluble sugar levels have been postulated to play an important role in the control of a wide variety of plant metabolic and developmental pathways, the mechanisms by which plants respond to soluble sugar levels remain poorly understood. Plant responses to soluble sugar levels are also important in bioenergy production, as plant sugar responses are believed to help regulate both carbon fixation and carbon partitioning. For example, accumulation of soluble sugars, such as sucrose and glucose, in source tissues leads to feedback inhibition of photosynthesis, thereby decreasing rates of carbon fixation. Soluble sugar levels can also affect sink strengths, affecting the rates of accumulation of carbon-based compounds into both particular molecular forms (e.g. carbohydrates versus lipids versus proteins) and particular plant organs and tissues. Mutants of Arabidopsis that are defective in the ability to respond to soluble sugar levels were isolated and used as tools to identify some of the factors involved in plant sugar response. These sugar insensitive (sis) mutants were isolated by screening mutagenized seeds for those that were able to germinate and develop relatively normal shoot systems on media containing 0.3 M glucose or 0.3 M sucrose. At these sugar concentrations, wild-type Arabidopsis germinate and produce substantial root systems, but show little to no shoot development. Twenty-eight sis mutants were isolated during the course of four independent mutant screens. Based on a preliminary characterization of all of these mutants, sis3 and sis6 were chosen for further study. Both of these mutations appear to lie in previously uncharacterized loci. Unlike many other sugar-response mutants, sis3 mutants exhibit a wild-type or near wild-type response in all phytohormone-response assays conducted to date. The sis6-1 mutation is unusual in that it appears to be due to overexpression of a gene, rather than representing a loss of function mutation

  6. Allele Specific p53 Mutant Reactivation

    Yu, Xin; Vazquez, Alexei; Levine, Arnold J.; Carpizo, Darren R.

    2012-01-01

    Rescuing the function of mutant p53 protein is an attractive cancer therapeutic strategy. Using the NCI anticancer drug screen data, we identified two compounds from the thiosemicarbazone family that manifest increased growth inhibitory activity in mutant p53 cells, particularly for the p53R175 mutant. Mechanistic studies reveal that NSC319726 restores WT structure and function to the p53R175 mutant. This compound kills p53R172H knock-in mice with extensive apoptosis and inhibits xenograft tu...

  7. Biochemical and histological characterization of tomato mutants

    Carolina C. Monteiro

    2012-06-01

    Full Text Available Biochemical responses inherent to antioxidant systems as well morphological and anatomical properties of photomorphogenic, hormonal and developmental tomato mutants were investigated. Compared to the non-mutant Micro-Tom (MT, we observed that the malondialdehyde (MDA content was enhanced in the diageotropica (dgt and lutescent (l mutants, whilst the highest levels of hydrogen peroxide (H2O2 were observed in high pigment 1 (hp1 and aurea (au mutants. The analyses of antioxidant enzymes revealed that all mutants exhibited reduced catalase (CAT activity when compared to MT. Guaiacol peroxidase (GPOX was enhanced in both sitiens (sit and notabilis (not mutants, whereas in not mutant there was an increase in ascorbate peroxidase (APX. Based on PAGE analysis, the activities of glutathione reductase (GR isoforms III, IV, V and VI were increased in l leaves, while the activity of superoxide dismutase (SOD isoform III was reduced in leaves of sit, epi, Never ripe (Nr and green flesh (gf mutants. Microscopic analyses revealed that hp1 and au showed an increase in leaf intercellular spaces, whereas sit exhibited a decrease. The au and hp1 mutants also exhibited a decreased in the number of leaf trichomes. The characterization of these mutants is essential for their future use in plant development and ecophysiology studies, such as abiotic and biotic stresses on the oxidative metabolism.Neste trabalho, analisamos as respostas bioquímicas inerentes ao sistema antioxidante, assim como propriedades morfológicas e anatômicas de mutantes fotomorfogenéticos e hormonais de tomateiro. Comparados ao não mutante Micro-Tom (MT, observamos que o conteúdo de malondialdeído (MDA aumentou nos mutantes diageotropica (dgt e lutescent (l, enquanto os maiores níveis de H2O2 foram encontrados nos mutantes high pigment 1 (hp1 e aurea (au. Análises de enzimas antioxidantes mostraram que todos os mutantes reduziram a atividade de catalase (CAT quando comparado a MT. A

  8. Stress Granule-Defective Mutants Deregulate Stress Responsive Transcripts

    Yang, Xiaoxue; Shen, Yi; Garre, Elena; Hao, Xinxin; Krumlinde, Daniel; Cvijović, Marija; Arens, Christina; Nyström, Thomas; Liu, Beidong; Sunnerhagen, Per

    2014-01-01

    To reduce expression of gene products not required under stress conditions, eukaryotic cells form large and complex cytoplasmic aggregates of RNA and proteins (stress granules; SGs), where transcripts are kept translationally inert. The overall composition of SGs, as well as their assembly requirements and regulation through stress-activated signaling pathways remain largely unknown. We have performed a genome-wide screen of S. cerevisiae gene deletion mutants for defects in SG formation upon...

  9. Collaborative form(s)

    Gunn, Wendy

    Gunn asks us to consider beauty as collaborative forms of action generated by moving between design by means of anthropology and anthropology by means of design. Specifically, she gives focus to play-like reflexions on practices of designing energy products, systems and infrastructure. Design...... anthropology engages groups of people within collaborative, interdisciplinary, inter-organizational design processes and co-analytic activities vs. the individual anthropologist conducting studies of people. In doing anthropology by means of design as Gatt and Ingold (2013) have shown, design is considered the...... premise designing as a social process and can be understood as a material engagement and constructive critique involving participant observation....

  10. Variability of yield structure and of physical traits determining lodging resistance in barley mutants

    Krajewski P.

    1998-09-01

    Full Text Available The paper presents an analysis of the variability of yield structure traits and lodging resistance of 32 spring barley mutants. The mutants were obtained from the DH line HK-119 using a chemomutagen N-ni-troso-N-methylurea (MNLJ and helium-neon laser. The mutants were chosen in such a way that they represented a broad spectrum of plant height. The investigation allowed mutants with improved parameters of yield structure in comparison to the initial form HK-119 to be selected. The analysis of morphological and physical traits stem diameters, wall thickness and stem elasticity (Young's modulus made possible the relationship between these traits and lodging grade to be estimated. The lodging grade was assessed in field conditions on a 9 degree scale, where 1 means no lodging and 9 the highest degree of lodging. Mutants of different plant height, with desirable yield structure and improved lodging resistance, were identified.

  11. Radiation-sensitive mutants of yeast

    Nomenclature for various radiosensitive mutants of Saccharomyces cerevisiae is briefly discussed. Tables are presented to show results of allelism tests of most of the radiosensitive mutants isolated by various investigators together with a standardized rad locus designation and map positions of a number of rad loci in yeast

  12. PHENOTYPIC ANALYSIS OF OsTPKb LOSS OF FUNCTION MUTANT RICE LINES

    Isayenkov S. V.

    2015-08-01

    Full Text Available The results of screen and analysis of two OsTPKb rice mutant lines were described. The phenotypes and growth rate level of homozygous mutant plants of both rice lines were estimated. The electron microscopy of aleurone layer from forming seeds was performed. The OsTPKb mutant plants demonstrate lower growth rate in comparison with wild type plants. The loss of function OsTPKb mutations invariably led to (semisterile rice plants. The functional disruption of OsTPKb channel has negative impact on plant growth and development. It might completely change the cell morphology of aleurone layer.

  13. Characterization of a Bradyrhizobium japonicum ferrochelatase mutant and isolation of the hemH gene.

    Frustaci, J M; O'Brian, M R

    1992-01-01

    A Tn5-induced mutant of Bradyrhizobium japonicum, strain LORBF1, was isolated on the basis of the formation of fluorescent colonies, and stable derivatives were constructed in backgrounds of strains LO and I110. The stable mutant strains LOek4 and I110ek4 were strictly dependent upon the addition of exogenous hemin for growth in liquid culture and formed fluorescent colonies. The fluorescent compound was identified as protoporphyrin IX, the immediate precursor of protoheme. Cell extracts of s...

  14. Cellular Responses during Morphological Transformation in Azospirillum brasilense and Its flcA Knockout Mutant

    Hou, Xingsheng; McMillan, Mary; Joëlle V. F. Coumans; Poljak, Anne; Raftery, Mark J.; Pereg, Lily

    2014-01-01

    FlcA is a response regulator controlling flocculation and the morphological transformation of Azospirillum cells from vegetative to cyst-like forms. To understand the cellular responses of Azospirillum to conditions that cause morphological transformation, proteins differentially expressed under flocculation conditions in A. brasilense Sp7 and its flcA knockout mutant were investigated. Comparison of 2-DE protein profiles of wild-type (Sp7) and a flcA deletion mutant (Sp7-flcAΔ) revealed a to...

  15. Molecular Variability in Barley Structural Mutants Produced by Gamma Irradiation

    Single Sequence Repeat (SSR) and Amplified Fragment Length Polymorphism (AFLP) markers were used to survey gamma ray induced genetic variation in a set of 13 originally produced structural barley (H. vulgare L.) mutants from cv. Freya; including 8 single translocation lines, 3 double translocation lines and 2 multiple reconstructed karyotypes. Both marker systems contributed to the evaluation of the radiation induced DNA alterations and revealed in general 0.49% polymorphisms in the studied genotypes. AFLPs were observed with 3 out of 10 PstI/MseI primer combinations. Transmissible microsatellite instability at loci with perfect (AT)n repeats located in the introns of the rubisco activase and waxy was documented in three mutant lines. The results emphasize that in addition to point mutations, small indels (2bp) form the major group of the gamma induced DNA alterations. (author)

  16. AFM images of complexes between amylose and Aspergillus niger glucoamylase mutants, native and mutant starch binding domains: a model for the action of glucoamylase

    Morris, V. M.; Gunning, A. P.; Faults, C. B.;

    2005-01-01

    Atomic force microscopy has been used to investigate the complexes formed between high molecular weight amylose chains and Aspergillus niger glucoamylase mutants (E400Q and W52F), wild-type A. niger starch binding domains (SBDS), and mutant SBDs (W563K and W590K) lacking either of the two starch...... for the assembly of an expanded amylosic double helix. T his model for amylose-SBD binding has been used to propose a molecular mechanism for the role of the SBD in the hydrolytic action of glucoamylase on starch granules. The SBDs are considered to recognise the ends of amylosic double helices formed...

  17. Mutants dissecting development and behaviour in drosophila

    We have traced in this paper the progress in Drosophila genetics research from the 1960s, at the IARI, spearheaded by the visionary insight of M. S. Swaminathan. The work started with the study of indirect effect of radiation and the synergistic interaction of physical and chemical mutagens on chromosomal and genetic changes. This paved the way for the study of single gene mutants in dissecting developmental and behavioural processes. New genes discovered by us have been shown to encode conserved cell signalling molecules controlling developmental and behavioural pathways. With the complete sequencing of the Drosophila genome, in the year 2000, mounting evidence for the homology between Drosophila and human genes controlling genetic disorders became available. This has led to the fly becoming an indispensable tool for studying human diseases as well as a model to test for drugs and pharmaceuticals against human diseases and complex behavioural processes. For example wingless in Drosophila belongs to the conserved Wnt gene family and aberrant WNT signalling is linked to a range of human diseases, most notably cancer. Inhibition as well as activation of WNT signalling form the basis of an effective therapy for some cancers as well as several other clinical conditions. Recent experiments have shown that WNTs might also normally participate in self-renewal, proliferation or differentiation of stem cells and altering WNT signalling might be beneficial to the use of stem cells for therapeutic means. Likewise, the stambhA mutant of Drosophila which was discovered for its temperature-dependent paralytic behaviour is the fly homologue of Phospholipase Cβ. Phospholipase C mediated G protein signalling plays a central role in vital processes controlling epilepsy, vision, taste, and olfaction in animals. Proteins of the G-signalling pathway are of intense research interest since many human diseases involve defects in G-protein signalling pathways. In fact, approximately 50

  18. Induction of Mutants in Durum Wheat

    This investigation presents a breeding program for induction and development of a new genotype of durum wheat, resistant to lodging with high yield, by irradiation durum wheat hybrids (F2) with gamma rays 100 Gy, during 1990-1997 cultivation seasons. This program involves: induction of variability, selection evaluation of the mutants at three locations: Twaitha (Baghdad) Latifya ( Babylon) and Swari (Kutt). All mutants showed resistance to lodging and there was a significant reduction in plant height. Mutant SIXIZ-22 surpassed other mutants and its origin in lodging resistance and plant height (83.5,82.8 and 89.4 cm) in the three locations at generation M5 and M6, respectively. Also, there were significant differences between mutant and their origin in the number of spikes/M2 and grain yild during the two successive generation. On the other hand, mutant IZxCO-105 surpassed other mutants in the number of spikes/M2 (231.8,242.3 and 292) and grain yield (4336,3376 and 5232 kg/ha) in all testing location, respectively . (authors) 14 refs., 4 tabs

  19. Temperature-sensitive rubisco mutant of Chlamydomonas

    The Chlamydomonas reinhardtii mutant 68-4PP is a temperature-sensitive mutant that lacks photosynthetic ability at 350C, but is able to grow photosynthetically at 250C. Genetic analysis indicated that 68-4PP is a chloroplast mutant that is allelic with known Rubisco large-subunit structural-gene mutants, implying that 68-4PP also resulted from a mutation in the large-subunit gene. The 68-4PP mutant has about 35% of the wild-type level of Rubisco holoenzyme and carboxylase activity when grown at 250C, but it has less than 10% of normal holoenzyme and carboxylase activity when grown at 350C. However, [35S]-sulfate pulse labeling showed that Rubisco subunits were synthesized at normal rates at both temperatures. More significantly, the ratio of carboxylase activity in the absence and presence of oxygen at a limiting CO2 concentration (6.6 μM) was about 2.2 for the mutant enzyme, as compared to about 3.0 for the wild-type enzyme. The decreased ratio of the mutant enzyme is maternally inherited, indicating that this reduced oxygen sensitivity results from a mutation in chloroplast DNA. The authors have recently cloned the 68-4PP Rubisco large-subunit gene, and DNA sequencing is in progress

  20. Development mutants of anabaena doliolum defective in repair of UV-damage

    Nitrosoguanidine induced 'blue' pigment mutants of the blue-green alga anabaena doliolum were isolated. The blue-mutants on further characterization were grouped into three developmental phenotypes - (i) those forming doli-form blue-spores of heterogenous size i.e., Ad 011, (ii) those forming spheroidal cells in the stationary phase, some of which behave like spores on transfer to fresh medium i.e., Ad 012, and (iii) those showing no sporulation and conditionally producing abnormal cells in the presence of combined nitrogen only i.e., Ad 007. The former two classes of mutants showed the formation of abnormal cells irrespective of the presence or absence of combined nitrogen sources in the medium. The formation of abnormal cells in the filaments of the above mutants were distinguished by their larger size and irregular mode of division leading to true-branch formation. The comparative characterization of these mutant strains with the parental one showed sluggish growth, increased UV-sensitivity, almost unchanged photorepair capacity, a marked change in the pigment composition and relative resistance to nitrosoguanidine. Irregular cell division in both space and time in the mutant strains and their increased sensitivity to ultraviolet irradiation indicate the possible involvement of dark repair system in maintaining the precision of cell cylce in this alga. (orig.) 891 AJ/orig. 892 HIS

  1. Productive potentials of short stemmed wheat mutants

    Air dry F2 seeds of the cross Skorospelka-35xMexipak were gamma irradiated (5 krad). It was established that the new short-stemmed wheat mutants can olay an important role both in hybrid combination breeding and as direct cultivars. Some of these mutants (No. 65, 67-I, 67-II, etc.), proved very promising because of their high productivity combined with other valuable biological and economic characters. The results obtained show also the great potentials and the perspectives of the method of combining hybrid and induced mutant variability. (author)

  2. Molecular Marker Development and Linkage Analysis in Three Low Phytic Acid Barley (Hordeum vulgare) Mutant Lines

    Phytate is the primary form of phosphorus found in mature cereal grain. This form of phosphorus is not available to monogastric animals due to a lack of the enzyme phytase in their digestive tract. Several barley low phytic acid (lpa) mutants have been identified that contain substantial decreases...

  3. Induction and isolation of mutants in sugarcane

    A review of the progress made on the induction of mutations in sugarcane at the Sugarcane Breeding Institute, Coimbatore, is presented. A description of some of the mutants is given. A few disease-resistant mutants have been obtained. Yield of C.C.S./ha of some of the mutants has surpassed the parent variety. Selection based on individual canes has increased the mutation rate and stability of mutants. Different techniques such as decapitation, closer planting and growing vM1 generation at different N levels have been observed to be promising methods to increase mutation rate. Raising of plants from mutated tissues by in vitro culture seems to be a potential tool in induced mutagenesis in sugarcane. (author)

  4. Properties of mutants of haemophilus influenzae deficient in ATP-dependent deoxyribonuclease

    Setlow, J.K.

    1976-01-01

    Eight isogenic Haemophilus influenzae strains whose extracts lack ATP-dependent deoxyribonuclease activity (Add/sup -/ mutants) form three complementation and genetic linkage groups. Since there are known to be three subunits of the enzyme, these data suggest that each of the three genes specifies a different subunit. Gel electrophoresis of partially purified mutant extracts indicates that the smallest subunit is missing in one of the groups but is present in all the other mutants. The mutants are more sensitive to a variety of chemical agents than the wild type. The most sensitive mutants lack the ATPase activity associated with the enzyme. These strains exhibit aberrant incorporation of tritiated thymidine, which starts up more rapidly and shuts off sooner than in the wild type. An extracellular compound is responsible for most of this effect, in that wild type cells put into medium in which Add/sup -/ cells have been growing show a similar aberrant incorporation. The effect of these media can be mimicked by cyclic AMP and cyclic GMP, although millimolar concentrations are required. It is postulated that the Add/sup -/ mutants are more permeable to many substances than the wild type, partly because of the extracellular compound usually surrounding them, and the increased permeability might be responsible for the mutants' nonviability.

  5. A new Arabidopsis mutant induced by ion beams affects flavonoid synthesis with spotted pigmentation in testa

    A new stable mutant of Arabidopsis thaliana with a spotted pigment in the seed coat, named anthocyanin spotted testa (ast), was induced by carbon ion irradiation. The spotted pigmentation of ast mutant was observed in immature seeds from 1-2 days after flowering (DAF), at the integument of the ovule, and spread as the seed coat formed. Anthocyanin accumulation was about 6 times higher in ast mutant than in the wild-type at 6 DAF of the immature seeds, but was almost the same in mature dry seeds. A higher anthocyanin accumulation was not observed in the seedlings, leaves or floral buds of ast mutant compared with the wild-type, which suggests that a high accumulation of anthocyanins is specific to the seed coat of the immature ast seeds. Reciprocal crosses between ast mutant and the wild-type indicated that ast is a single recessive gene mutation and segregates as a delayed inheritance. The results of crossing with tt7 and ttg mutants also confirmed that the AST gene is probably a regulatory locus that controls flavonoid biosynthesis. A mapping analysis revealed that the gene is located on chromosome I and is closely linked to the SSLP DNA marker nga280 with a distance of 3.2 cM. AST has been registered as a new mutant of Arabidopsis

  6. FORM development

    Vermaseren, J. A. M.

    2011-01-01

    I give an overview of FORM development based on a few pilot projects, explaining how they have influenced the FORM capabilities. Next I explain what is happnening right now in the field of Open Sourcing and the FORM Forum.

  7. Induced mutants for rice functional genomics

    Induced mutations have been playing important roles in both crop germplasm enhancement and new variety development. With the completion of the rice genome sequence, the study on functional genomics in rice has become a major task. Construction of rice mutant library is an essential approach for rice functional genomics study. This paper briefly reviewed several common techniques for generation of rice mutant library and its application in rice functional research, taking examples of developing rice chloroplast development related mutant library to provide the basic materials for functional genes cloning. A rice Chlorophyll (Chl) deficient mutant, yellow-green leaf1 (ygl1), was isolated, which showed yellow-green leaves in young plants with decreased Chl synthesis, increased level of tetrapyrrole intermediates, and delayed chloroplast development. Genetic analysis demonstrated that the phenotype of ygl1 was caused by a recessive mutation in a nuclear gene. The ygl1 locus was mapped to chromosome 5. A missense mutation was found in a highly conserved residue of YGL1 in the ygl1 mutant, resulting in reduction of the enzymatic activity. Another green-revertible albino leaf (gral) mutant involved in chloroplast development was screened from a M2 population induced by 300Gy 60Co gamma rays irradiation to the seeds of rice male sterile line PA64S with the collaboration of Zhejiang University. The mutant seedling leaves exhibit albino firstly but turn to normal green after the sixth leaf extended thoroughly. Systematical research including photosynthetic pigment, chloroplast microscopic observation and gene cloning was carried out on the gral mutant. (author)

  8. Radiation induced promising mutants in Cowpea

    Cowpea (Vigna unguiculata L. Walp.) is an important legume crop of the tropics and subtropics of Asia, Africa and America. Breeding objectives in recent years have been to combine high yields with upright growth habit, bushy dwarf determinate plant type, early maturity and large seed size in addition to resistance to biotic and abiotic stresses. With a view to achieving these objectives and creating additional - variability, the seeds of an elite variety V-130 were irradiated with 200 Gy of gamma rays, and a number of morphological mutants were isolated. The mutants with desirable characters like erect growth habit, dwarf, large seed size, and high pod number were isolated in the M2 generation and studied further in subsequent generations for their yield potential and other characteristics. The dwarf plant mutant TCM 77-4, characterised by reduced plant height, bushy growth, large seed size and absence of tendril bred true when grown in rabi seasons, but behaved like parent in respect of growth habit in kharif season. It was far superior to the parent in respect of seed size in all the seasons. The mutant is envisaged to be the most suitable for rice fallows. Among the several promising mutants with large seed size, the mutant TCM 13-5 showed a test weight of 16.8 g against 8.8 g of the parent. A mutant with large pod number designated as TCM 121-8 showed promise with its very high yield, when grown in summer albeit with delayed maturity. Several mutants with maturity similar to that of the parent have shown higher seed yield. The variability generated through the radiation- induced mutation is being utilised for creating novel high yielding early maturing varieties of cowpea. (author)

  9. Barley mutant line with high protein yield

    Mutation breeding was initiated in 1969 at the Agricultural Research Institute, Nicosia, aiming at developing high yielding barley lines having also high protein or lysine content. The final results were reported at the FAO/IAEA Research Co-ordination Meeting at Nicosia in 1980. At that time some lines were superior to their mother line in grain yield, protein content or protein yield. However, high yield is essential for feed-barley as there is no premium price for protein content or quality. In the experiments reported earlier, the mean grain yield of mutant M-Att-73-337-1 was 3202 kg/ha, 9.9% higher than the mother variety 'Attiki'. The Kjeldahl protein content was 12.7% for the mutant line and 13.4% for the mother variety. The mutant line was further evaluated in field trials (11 m2 plots and 6 replications) during 1983-88, along with other promising material from the breeding programme. The mutant line outyielded its mother variety by 9.7% in grain yield and 16% in straw yield. These increases are apparently the result of increased 1000-grain weight and a higher number of culms per m2. Protein content of the mutant line was slightly lower, but its protein yield was 5.5% higher. The yield of the mutant line over 16 trials during 1983-88 was also 4% higher than the yield of the main commercially grown variety Athenais

  10. Pattern formation mechanisms in motility mutants of Myxococcus xanthus

    Starruss, Joern; Jakovljevic, Vladimir; Sogaard-Andersen, Lotte; Deutsch, Andreas; Baer, Markus

    2016-01-01

    Formation of spatial patterns of cells is a recurring theme in biology and often depends on regulated cell motility. Motility of M. xanthus depends on two motility machineries: the S-engine and A-engine. Moving M. xanthus cells can organize into spreading colonies or spore-filled fruiting bodies depending on their nutritional status. To understand these two pattern formation processes and the contributions by the two motility machineries, as well as cell reversal, we analyze spatial self-organization in 3 strains: i) a mutant that moves unidirectionally without reversing by the A-motility system only, ii) a unidirectional mutant that is also equipped with the S-motility system, and iii) the wild-type that, in addition to the two motility systems, reverses its direction of movement. The mutant moving by the A-engine illustrates that collective motion in the form of large moving clusters can arise in gliding bacteria due to steric interactions of the rod-shaped cells, without the need of invoking any biochemica...

  11. Generation and analysis of bacteriorhodopsin mutants with the potential for biotechnological applications.

    Saeedi, P; Moosaabadi, J Mohammadian; Sebtahmadi, S Sina; Mehrabadi, J Fallah; Behmanesh, M; Nejad, H Rouhani; Nazaktabar, A

    2012-01-01

    The properties of bacteriorhodopsin (BR) can be manipulated by genetic engineering. Therefore, by the methods of gene engineering, Asp85 was replaced individually by two other amino acids (D85V, D85S). The resulting recombinant proteins were assembled into soybean vesicles retinylated to form functional BR-like nano-particles. Proton translocation was almost completely abrogated by the mutant D85S, while the D85V mutant was partially active in pumping protons. Compared with wild type, maximum absorption of the mutants, D85V and D85S, were 563 and 609 nm, which illustrated 5 nm reductions (blue shift) and 41 nm increases (red shift), respectively. Since proton transport activity and spectroscopic activities of the mutants are different, a wide variety of membrane bioreactors (MBr) have been developed. Modified proteins can be utilized to produce unique photo/Electro-chromic materials and tools. PMID:22976247

  12. Characterization of a cytochalasin D-resistant mutant of Entamoeba histolytica.

    de la Garza, M; Gallegos, B; Meza, I

    1989-01-01

    Characterization of a cytochalasin D-resistant mutant of the human parasite Entamoeba histolytica capable of growing at 10 microM cytochalasin is described. The mutant cells also show resistance to 5 mM colchicine and 100 microM cytochalasin B, drugs proved deleterious for wild type trophozoites. The mutants show increased osmotic fragility and electric mobility but reduced phagocytic activity, and agglutination by Concanavalin A. On the other hand pinocytic activity remains unaltered when compared with the wild type cells. Polymerized actin, seen by staining with phalloidin, often appears polarized to one end of the trophozoites and forms few of the endocytic invaginations found in wild type amebas. An altered distribution of part of the actin could explain the differences in surface properties and motility observed in the mutant amebas. PMID:2557444

  13. Interspecific complementation between mouse and Chinese hamster cell mutants hypersensitive to ionizing radiation

    Interspecific and intraspecific hybrids were formed between mouse and Chinese hamster cell mutants hypersensitive to ionizing radiation and their radiosensitivities were examined. Chinese hamster cell mutants irs1, irs2 and irs3 and mouse mammary carcinoma cell mutants SX9 and SX10 have been found to belong to five different complementation groups. A radiosensitive mouse lymphoma cell line L5178Y-S has been demonstrated to be different from the X-ray sensitive mouse cell mutants M10 and LX830, both of which are derived from L5178Y cells, in their complementation groups. L5178Y-S is also distinct from SX9 and SX10. (author)

  14. Prion propagation in cells expressing PrP glycosylation mutants.

    Salamat, Muhammad K; Dron, Michel; Chapuis, Jérôme; Langevin, Christelle; Laude, Hubert

    2011-04-01

    Infection by prions involves conversion of a host-encoded cell surface protein (PrP(C)) to a disease-related isoform (PrP(Sc)). PrP(C) carries two glycosylation sites variably occupied by complex N-glycans, which have been suggested by previous studies to influence the susceptibility to these diseases and to determine characteristics of prion strains. We used the Rov cell system, which is susceptible to sheep prions, to generate a series of PrP(C) glycosylation mutants with mutations at one or both attachment sites. We examined their subcellular trafficking and ability to convert into PrP(Sc) and to sustain stable prion propagation in the absence of wild-type PrP. The susceptibility to infection of mutants monoglycosylated at either site differed dramatically depending on the amino acid substitution. Aglycosylated double mutants showed overaccumulation in the Golgi compartment and failed to be infected. Introduction of an ectopic glycosylation site near the N terminus fully restored cell surface expression of PrP but not convertibility into PrP(Sc), while PrP(C) with three glycosylation sites conferred cell permissiveness to infection similarly to the wild type. In contrast, predominantly aglycosylated molecules with nonmutated N-glycosylation sequons, produced in cells expressing glycosylphosphatidylinositol-anchorless PrP(C), were able to form infectious PrP(Sc). Together our findings suggest that glycosylation is important for efficient trafficking of anchored PrP to the cell surface and sustained prion propagation. However, properly trafficked glycosylation mutants were not necessarily prone to conversion, thus making it difficult in such studies to discern whether the amino acid changes or glycan chain removal most influences the permissiveness to prion infection. PMID:21248032

  15. Rhodopsin mutant P23H destabilizes rod photoreceptor disk membranes.

    Mohammad Haeri

    Full Text Available Mutations in rhodopsin cause retinitis pigmentosa in humans and retinal degeneration in a multitude of other animals. We utilized high-resolution live imaging of the large rod photoreceptors from transgenic frogs (Xenopus to compare the properties of fluorescently tagged rhodopsin, Rho-EGFP, and Rho(P23H-EGFP. The mutant was abnormally distributed both in the inner and outer segments (OS, accumulating in the OS to a concentration of ∼0.1% compared to endogenous opsin. Rho(P23H-EGFP formed dense fluorescent foci, with concentrations of mutant protein up to ten times higher than other regions. Wild-type transgenic Rho-EGFP did not concentrate in OS foci when co-expressed in the same rod with Rho(P23H-EGFP. Outer segment regions containing fluorescent foci were refractory to fluorescence recovery after photobleaching, while foci in the inner segment exhibited recovery kinetics similar to OS regions without foci and Rho-EGFP. The Rho(P23H-EGFP foci were often in older, more distal OS disks. Electron micrographs of OS revealed abnormal disk membranes, with the regular disk bilayers broken into vesiculotubular structures. Furthermore, we observed similar OS disturbances in transgenic mice expressing Rho(P23H, suggesting such structures are a general consequence of mutant expression. Together these results show that mutant opsin disrupts OS disks, destabilizing the outer segment possibly via the formation of aggregates. This may render rods susceptible to mechanical injury or compromise OS function, contributing to photoreceptor loss.

  16. Characterization of a Lignified Secondary Phloem Fibre‐deficient Mutant of Jute (Corchorus capsularis)

    SENGUPTA, GARGI; PALIT, P.

    2004-01-01

    • Background and Aims High lignin content of lignocellulose jute fibre does not favour its utilization in making finer fabrics and other value‐added products. To aid the development of low‐lignin jute fibre, this study aimed to identify a phloem fibre mutant with reduced lignin. • Methods An x‐ray‐induced mutant line (CMU) of jute (Corchorus capsularis) was morphologically evaluated and the accession (CMU 013) with the most undulated phenotype was compared with its normal parent (JRC 212) for its growth, secondary fibre development and lignification of the fibre cell wall. • Key Results The normal and mutant plants showed similar leaf photosynthetic rates. The mutant grew more slowly, had shorter internodes and yielded much less fibre after retting. The fibre of the mutant contained 50 % less lignin but comparatively more cellulose than that of the normal type. Differentiation of primary and secondary vascular tissues throughout the CMU 013 stem was regular but it did not have secondary phloem fibre bundles as in JRC 212. Instead, a few thin‐walled, less lignified fibre cells formed uni‐ or biseriate radial rows within the phloem wedges of the middle stem. The lower and earliest developed part of the mutant stem had no lignified fibre cells. This developmental deficiency in lignification of fibre cells was correlated to a similar deficiency in phenylalanine ammonia lyase activity, but not peroxidase activity, in the bark tissue along the stem axis. In spite of severe reduction in lignin synthesis in the phloem cells this mutant functioned normally and bred true. • Conclusions In view of the observations made, the mutant is designated as deficient lignified phloem fibre (dlpf). This mutant may be utilized to engineer low‐lignin jute fibre strains and may also serve as a model to study the positional information that coordinates secondary wall thickening of fibre cells. PMID:14707004

  17. Officially released mutant varieties in China

    The use of mutation techniques for crop improvement in China has a long and well-established tradition of more than 50 years. As the result of intensive research in many institutes dealing with application of nuclear technologies more than 620 cultivars of 44 crop species have been released. Numerous mutant varieties have been grown on a large scale bringing significant economic impact, sustaining crop production and greatly contributing to increase of food production also in stress prone areas of the country. However, there is still missing information not only on the number of mutant varieties released in particular crop species but also on mutagens applied, selection approaches and on the use of mutants in cross breeding. Numerous Chinese scientists collected and systematized this information. Results of their work were often published in local scientific journals in the Chinese language and as such were unavailable to breeders from other countries. Having this in mind, we requested Dr. Liu Luxiang, the Director of the Department of Plant Mutation Breeding and Genetics, Institute for Application of Atomic Energy, Chinese Academy of Agricultural Sciences in Beijing to help us in finding as much information as possible on mutant varieties officially released in China. The data has been collected in close collaboration with his colleagues from various institutions all over the country and then evaluated, edited and prepared for publication by our team responsible for the FAO/IAEA Database of Officially Released Mutant Varieties. We would like to thank all Chinese colleagues who contributed to this list of Chinese mutant varieties. We hope that this publication will stimulate plant breeders in China to collect more information on released mutant varieties and especially on the use of mutated genes in cross breeding. (author)

  18. Development of high yielding mutants in lentil

    Full text: Lentil (Lens culinaris Medik.) locally known as Masoor, is the second most important rabi pulse crop, after chickpea, in Pakistan. It is cultivated on an area of over 63,400 ha, which constitutes about 4.83% of the total area under pulses. The annual production of the crop is 28,200 tones with an average yield of 445 kg/ha. Yield at the national level is very low, about one-half of the world's yield, which is mainly due to non-availability of high yield potential genotypes. Keeping in view the importance of mutants in developing a large number of new varieties, an induced mutations programme was initiated at AEARC, Tandojam during 1987-88, to develop high yielding varieties in lentil. For this, seeds of two lentil varieties, 'Masoor-85' and 'ICARDA-8' had been irradiated with gamma-rays ranging from 100-600 Gy in NIAB, Faisalabad during 1990. Selections were made in M2 on the basis of earliness, plant height, branches/plant and 100 grain weight. After confirming these mutants in M3 they were promoted in station yield trials and studied continuously for three consecutive years (1993- 1995). Overall results revealed that these mutants have consistent improvement of earliness in flowering and maturity. Plant height also increased in all mutant lines except AEL 23/40/91 where reduction in this attribute was observed as compared to parent variety. Mutant lines AEL 49/20/91 and AEL 13/30/91 showed improvement in 100 grain weight. The improvement of some agronomic characters enhanced the yield of mutant lines in comparison to parent varieties (Masoor-85 and ICARDA-8). The diversity in yield over the respective parents was computed from 6.94 to 60.12%. From these encouraging results it is hoped that mutant lines like AEL 12/30/91 and AEL 49/20/91 may serve as potential lentil genotypes in future. (author)

  19. Stability of Iowa mutant and wild type Aβ-peptide aggregates

    Alred, Erik J.; Scheele, Emily G.; Berhanu, Workalemahu M.; Hansmann, Ulrich H. E., E-mail: uhansmann@ou.edu [Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019 (United States)

    2014-11-07

    Recent experiments indicate a connection between the structure of amyloid aggregates and their cytotoxicity as related to neurodegenerative diseases. Of particular interest is the Iowa Mutant, which causes early-onset of Alzheimer's disease. While wild-type Amyloid β-peptides form only parallel beta-sheet aggregates, the mutant also forms meta-stable antiparallel beta sheets. Since these structural variations may cause the difference in the pathological effects of the two Aβ-peptides, we have studied in silico the relative stability of the wild type and Iowa mutant in both parallel and antiparallel forms. We compare regular molecular dynamics simulations with such where the viscosity of the samples is reduced, which, we show, leads to higher sampling efficiency. By analyzing and comparing these four sets of all-atom molecular dynamics simulations, we probe the role of the various factors that could lead to the structural differences. Our analysis indicates that the parallel forms of both wild type and Iowa mutant aggregates are stable, while the antiparallel aggregates are meta-stable for the Iowa mutant and not stable for the wild type. The differences result from the direct alignment of hydrophobic interactions in the in-register parallel oligomers, making them more stable than the antiparallel aggregates. The slightly higher thermodynamic stability of the Iowa mutant fibril-like oligomers in its parallel organization over that in antiparallel form is supported by previous experimental measurements showing slow inter-conversion of antiparallel aggregates into parallel ones. Knowledge of the mechanism that selects between parallel and antiparallel conformations and determines their relative stability may open new avenues for the development of therapies targeting familial forms of early-onset Alzheimer's disease.

  20. Stability of Iowa mutant and wild type Aβ-peptide aggregates

    Recent experiments indicate a connection between the structure of amyloid aggregates and their cytotoxicity as related to neurodegenerative diseases. Of particular interest is the Iowa Mutant, which causes early-onset of Alzheimer's disease. While wild-type Amyloid β-peptides form only parallel beta-sheet aggregates, the mutant also forms meta-stable antiparallel beta sheets. Since these structural variations may cause the difference in the pathological effects of the two Aβ-peptides, we have studied in silico the relative stability of the wild type and Iowa mutant in both parallel and antiparallel forms. We compare regular molecular dynamics simulations with such where the viscosity of the samples is reduced, which, we show, leads to higher sampling efficiency. By analyzing and comparing these four sets of all-atom molecular dynamics simulations, we probe the role of the various factors that could lead to the structural differences. Our analysis indicates that the parallel forms of both wild type and Iowa mutant aggregates are stable, while the antiparallel aggregates are meta-stable for the Iowa mutant and not stable for the wild type. The differences result from the direct alignment of hydrophobic interactions in the in-register parallel oligomers, making them more stable than the antiparallel aggregates. The slightly higher thermodynamic stability of the Iowa mutant fibril-like oligomers in its parallel organization over that in antiparallel form is supported by previous experimental measurements showing slow inter-conversion of antiparallel aggregates into parallel ones. Knowledge of the mechanism that selects between parallel and antiparallel conformations and determines their relative stability may open new avenues for the development of therapies targeting familial forms of early-onset Alzheimer's disease

  1. Agronomically valuable mutant lines of castor

    Dry seeds of four castor varieties (VNIIMK 165-improved, VNIIMK 18, Chervonnaya and Antika) were treated with six chemical mutagens, N-nitroso-N-methyl urea (NMU), N-nitroso-N-ethyl urea (NEU), dimethyl sulphate (DMS), diethyl sulphate (DES), ethylenimine (EI) and 1,4-bis-diazoacetyl-butane (DAB) in various doses during 18 hours. About 40,000 plants were studied in M2 and 80 types of mutations were found, including a number of valuable mutants: short-stemmed, semi-dwarf, dwarf, early maturing, with female and interspersed types of racemes, highly productive etc. Based on trials in M3-M4, on small plots with two or three replications, the superior mutant lines were identified. The best mutants are presented in the table. Early maturation is very important for growing castor in the USSR, as it is the predecessor of winter wheat in crop rotation. The mutants M2-323 and Ml-83 are of great value as they show early maturation and high yield. Their productivity is mainly conditioned by a high percentage of interspersed plants. The reduction of plant height is of great importance for the successful combine harvesting of castor. Mutant lines M2-119 and Ml-284 characterised by low plant height and high yield are very interesting in this respect. The obtained initial material will be used in further breeding work

  2. Hepatitis B surface gene 145 mutant as a minor population in hepatitis B virus carriers

    Komatsu Haruki

    2012-01-01

    children and adults. HBV carriers might have the a determinant mutants as a minor form.

  3. Mutants with enhanced nitrogenase activity in hydroponic Azospirillum brasilense-wheat associations.

    Pereg Gerk, L; Gilchrist, K; Kennedy, I R

    2000-05-01

    The effect of a mutation affecting flocculation, differentiation into cyst-like forms, and root colonization on nitrogenase expression by Azospirillum brasilense is described. The gene flcA of strain Sp7 restored these phenotypes in spontaneous mutants of both strains Sp7 and Sp245. Employing both constitutive pLA-lacZ and nifH-lacZ reporter fusions expressed in situ, the colony morphology, colonization pattern, and potential for nitrogenase activity of spontaneous mutants and flcA Tn5-induced mutants were established. The results of this study show that the ability of Sp7 and Sp245 mutant strains to remain in a vegetative form improved their ability to express nitrogenase activity in association with wheat in a hydroponic system. Restoring the cyst formation and colonization pattern to the spontaneous mutant Sp7-S reduced nitrogenase activity rates in association with plants to that of the wild-type Sp7. Although Tn5-induced flcA mutants showed higher potentials for nitrogenase expression than Sp7, their potentials were lower than that of Sp7-S, indicating that other factors in this strain contribute to its exceptional nitrogenase activity rates on plants. The lack of lateral flagella is not one of these factors, as Sp7-PM23, a spontaneous mutant impaired in swarming and lateral-flagellum production but not in flocculation, showed wild-type nitrogenase activity and expression. The results also suggest factors of importance in evolving an effective symbiosis between Azospirillum and wheat, such as increasing the availability of microaerobic niches along the root, increased supply of carbon sources by the plant, and the retention of the bacterial cells in vegetative form for faster metabolism. PMID:10788397

  4. Biochemical characterization and cellular effects of CADASIL mutants of NOTCH3.

    He Meng

    Full Text Available Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL is the best understood cause of dominantly inherited stroke and results from NOTCH3 mutations that lead to NOTCH3 protein accumulation and selective arterial smooth muscle degeneration. Previous studies show that NOTCH3 protein forms multimers. Here, we investigate protein interactions between NOTCH3 and other vascular Notch isoforms and characterize the effects of elevated NOTCH3 on smooth muscle gene regulation. We demonstrate that NOTCH3 forms heterodimers with NOTCH1, NOTCH3, and NOTCH4. R90C and C49Y mutant NOTCH3 form complexes which are more resistant to detergents than wild type NOTCH3 complexes. Using quantitative NOTCH3-luciferase clearance assays, we found significant inhibition of mutant NOTCH3 clearance. In coculture assays of NOTCH function, overexpressed wild type and mutant NOTCH3 significantly repressed NOTCH-regulated smooth muscle transcripts and potently impaired the activity of three independent smooth muscle promoters. Wildtype and R90C recombinant NOTCH3 proteins applied to cell cultures also blocked canonical Notch fuction. We conclude that CADASIL mutants of NOTCH3 complex with NOTCH1, 3, and 4, slow NOTCH3 clearance, and that overexpressed wild type and mutant NOTCH3 protein interfere with key NOTCH-mediated functions in smooth muscle cells.

  5. Amphid defective mutant of Caenorhabditis elegans.

    De Riso, L; Ristoratore, F; Sebastiano, M; Bazzicalupo, P

    1994-01-01

    Studies are reported on a chemoreception mutant which arose in a mutator strain. The mutant sensory neurons do not stain with fluoresceine isothiocyanate (Dyf phenotype), hence the name, dyf-1, given to the gene it identifies. The gene maps on LGI, 0.4 map units from dpy-5 on the unc-11 side. The response of mutant worms to various repellents has been studied and shown to be partially altered. Other chemoreception based behaviors are less affected. The cilia of the sensory neurons of the amphid are shorter than normal and the primary defect may be in the capacity of the sheath cells to secrete the matrix material that fills the space between cilia in the amphid channel. Progress toward the molecular cloning of the gene is also reported. Relevant results from other laboratories are briefly reviewed. PMID:7896139

  6. Homologous series of induced early mutants in Indica rice. Pt.3: The relationship between the induction of homologous series of early mutants and its different pedigree

    The percentage of homologous series of early mutants (PHSEM) induced by irradiation was closely related to its pedigree. This study showed that PHSEM for varieties with the same pedigree were similar, and there were three different level of dominance (high, low and normal) in the homologous series induced from different pedigree. The PHSEM for varieties derived form distant-relative-parents were higher than that derived from close-relative-parents. There was the dominance pedigree for the induction of homologous series of early mutants. IR8(Peta x DGWG), IR127 (Cpslo x Sigadis) and IR24 (IR8 x IR127) were dominant pedigree, and varieties derived from them could be easily induced the homologous series of early mutants

  7. Nuclear protein import is reduced in cells expressing nuclear envelopathy-causing lamin A mutants

    Lamins, which form the nuclear lamina, not only constitute an important determinant of nuclear architecture, but additionally play essential roles in many nuclear functions. Mutations in A-type lamins cause a wide range of human genetic disorders (laminopathies). The importance of lamin A (LaA) in the spatial arrangement of nuclear pore complexes (NPCs) prompted us to study the role of LaA mutants in nuclear protein transport. Two mutants, causing prenatal skin disease restrictive dermopathy (RD) and the premature aging disease Hutchinson Gilford progeria syndrome, were used for expression in HeLa cells to investigate their impact on the subcellular localization of NPC-associated proteins and nuclear protein import. Furthermore, dynamics of the LaA mutants within the nuclear lamina were studied. We observed affected localization of NPC-associated proteins, diminished lamina dynamics for both LaA mutants and reduced nuclear import of representative cargo molecules. Intriguingly, both LaA mutants displayed similar effects on nuclear morphology and functions, despite their differences in disease severity. Reduced nuclear protein import was also seen in RD fibroblasts and impaired lamina dynamics for the nucleoporin Nup153. Our data thus represent the first study of a direct link between LaA mutant expression and reduced nuclear protein import.

  8. Nuclear protein import is reduced in cells expressing nuclear envelopathy-causing lamin A mutants

    Busch, Albert; Kiel, Tilman; Heupel, Wolfgang-M. [University of Wuerzburg, Institute of Anatomy and Cell Biology, Koellikerstrasse 6, 97070 Wuerzburg (Germany); Wehnert, Manfred [Institute of Human Genetics, University of Greifswald, Greifswald (Germany); Huebner, Stefan, E-mail: stefan.huebner@mail.uni-wuerzburg.de [University of Wuerzburg, Institute of Anatomy and Cell Biology, Koellikerstrasse 6, 97070 Wuerzburg (Germany)

    2009-08-15

    Lamins, which form the nuclear lamina, not only constitute an important determinant of nuclear architecture, but additionally play essential roles in many nuclear functions. Mutations in A-type lamins cause a wide range of human genetic disorders (laminopathies). The importance of lamin A (LaA) in the spatial arrangement of nuclear pore complexes (NPCs) prompted us to study the role of LaA mutants in nuclear protein transport. Two mutants, causing prenatal skin disease restrictive dermopathy (RD) and the premature aging disease Hutchinson Gilford progeria syndrome, were used for expression in HeLa cells to investigate their impact on the subcellular localization of NPC-associated proteins and nuclear protein import. Furthermore, dynamics of the LaA mutants within the nuclear lamina were studied. We observed affected localization of NPC-associated proteins, diminished lamina dynamics for both LaA mutants and reduced nuclear import of representative cargo molecules. Intriguingly, both LaA mutants displayed similar effects on nuclear morphology and functions, despite their differences in disease severity. Reduced nuclear protein import was also seen in RD fibroblasts and impaired lamina dynamics for the nucleoporin Nup153. Our data thus represent the first study of a direct link between LaA mutant expression and reduced nuclear protein import.

  9. Extended region of nodulation genes in Rhizobium meliloti 1021. I. Phenotypes of Tn5 insertion mutants

    Rhizobium meliloti Nod- mutant WL131, a derivative of wild-type strain 102F51, was complemented by a clone bank of wild-type R. meliloti 1021 DNA, and clone pRmJT5 was recovered. Transfer of pRmJT5 conferred alfalfa nodulation on other Rhizobium species, indicating a role in host range determination for pRmJT5. Mutagenesis of pRmJT5 revealed several segments in which transposon insertion causes delay in nodulation, and/or marked reduction of the number of nodules formed on host alfalfa plants. The set of mutants indicated five regions in which nod genes are located; one mutant, nod-216, is located in a region not previously reported to encode a nodulation gene. Other mutant phenotypes correlated with the positions of open reading frames for nodH, nodF and nodE, and with a 2.2-kb EcoRI fragment. A mutant in nodG had no altered phenotype in this strain. One nodulation mutant was shown to be a large deletion of the common nod gene region. The authors present a discussion comparing the various studies made on this extended nod gene region

  10. Akt mediated ROS-dependent selective targeting of mutant KRAS tumors.

    Iskandar, Kartini; Rezlan, Majidah; Pervaiz, Shazib

    2014-10-01

    Reactive oxygen species (ROS) play a critical role in a variety of cellular processes, ranging from cell survival and proliferation to cell death. Previously, we reported the ability of a small molecule compound, C1, to induce ROS dependent autophagy associated apoptosis in human cancer cell lines and primary tumor cells (Wong C. et al. 2010). Our ongoing investigations have unraveled a hitherto undefined novel signaling network involving hyper-phosphorylation of Akt and Akt-mediated ROS production in cancer cell lines. Interestingly, drug-induced Akt activation is selectively seen in cell lines that carry mutant KRAS; HCT116 cells that carry the V13D KRAS mutation respond favorably to C1 while HT29 cells expressing wild type KRAS are relatively resistant. Of note, not only does the compound target mutant KRAS expressing cells but also induces RAS activation as evidenced by the PAK pull down assay. Corroborating this, pharmacological inhibition as well as siRNA mediated silencing of KRAS or Akt, blocked C1-induced ROS production and rescued tumor colony forming ability in HCT116 cells. To further confirm the involvement of KRAS, we made use of mutant KRAS transformed RWPE-1 prostate epithelial cells. Notably, drug-induced ROS generation and death sensitivity was significantly higher in RWPE-1-KRAS cells than the RWPE-1-vector cells, thus confirming the results obtained with mutant KRAS colorectal carcinoma cell line. Lastly, we made use of HCT116 mutant KRAS knockout cells (KO) where the mutant KRAS allele had been deleted, thus expressing a single wild-type KRAS allele. Exposure of the KO cells to C1 failed to induce Akt activation and mitochondrial ROS production. Taken together, results show the involvement of activated Akt in ROS-mediated selective targeting of mutant KRAS expressing tumors, which could have therapeutic implications given the paucity of chemotherapeutic strategies specifically targeting KRAS mutant cancers. PMID:26461287

  11. Results of utilization of Chernobyl radio mutant in breeding programs of Triticum Aestivum L

    During 1988-2007 at the research station in Bila Tserkva it was investigated the genetic changes in winter wheat occurred due to the ionizing radiation which appeared as the result of Chernobyl Nuclear Power Plant Accident. 239 accessions of common wheat which during two years in plantations in 1986 and in self-sowing 1987 grew near the Chernobyl Reactor were provided for our station for further investigations and analysis. It was planned to analyze the possibilities of their utilization in breeding by selection among them the mutants with attractive agronomic important traits with further introduction of them in breeding programs. Ever in M2 the large spectrum of mutations was found out. Because of genetic instability the mutant diversity each year was increased and up to present moment we have in collection up to 2000 mutants. Mainly among mutants in different generations appeared the plants with different kinds of abnormality in structure. We call them chimerical plants and they had no any value for breeding. More over the direct selection from mutants of all studied varieties did not perform the positive results because of high instability of all characteristic in many generations. In the same time the particular lines of mutants, which have advantage by some agronomic characteristics, were applied to the breeding programs. Mutants taken form the different generations (L147/91, BC 47 square head, dwarf 20104/89) were used for development of Lybid, Yasochka and Tsarivna varieties to utilize mutants' traits such as hardiness, drought tolerance, resistance to diseases and lodging, bred quality. The varieties were included in the State Variety Register of Ukraine. Another variety - Lisova Pisnya is included in the list of perspective ones. (author)

  12. Activation of the thrombopoietin receptor by mutant calreticulin in CALR-mutant myeloproliferative neoplasms.

    Araki, Marito; Yang, Yinjie; Masubuchi, Nami; Hironaka, Yumi; Takei, Hiraku; Morishita, Soji; Mizukami, Yoshihisa; Kan, Shin; Shirane, Shuichi; Edahiro, Yoko; Sunami, Yoshitaka; Ohsaka, Akimichi; Komatsu, Norio

    2016-03-10

    Recurrent somatic mutations of calreticulin (CALR) have been identified in patients harboring myeloproliferative neoplasms; however, their role in tumorigenesis remains elusive. Here, we found that the expression of mutant but not wild-type CALR induces the thrombopoietin (TPO)-independent growth of UT-7/TPO cells. We demonstrated that c-MPL, the TPO receptor, is required for this cytokine-independent growth of UT-7/TPO cells. Mutant CALR preferentially associates with c-MPL that is bound to Janus kinase 2 (JAK2) over the wild-type protein. Furthermore, we demonstrated that the mutant-specific carboxyl terminus portion of CALR interferes with the P-domain of CALR to allow the N-domain to interact with c-MPL, providing an explanation for the gain-of-function property of mutant CALR. We showed that mutant CALR induces the phosphorylation of JAK2 and its downstream signaling molecules in UT-7/TPO cells and that this induction was blocked by JAK2 inhibitor treatment. Finally, we demonstrated that c-MPL is required for TPO-independent megakaryopoiesis in induced pluripotent stem cell-derived hematopoietic stem cells harboring the CALR mutation. These findings imply that mutant CALR activates the JAK2 downstream pathway via its association with c-MPL. Considering these results, we propose that mutant CALR promotes myeloproliferative neoplasm development by activating c-MPL and its downstream pathway. PMID:26817954

  13. Novel Two-Step Hierarchical Screening of Mutant Pools Reveals Mutants under Selection in Chicks.

    Yang, Hee-Jeong; Bogomolnaya, Lydia M; Elfenbein, Johanna R; Endicott-Yazdani, Tiana; Reynolds, M Megan; Porwollik, Steffen; Cheng, Pui; Xia, Xiao-Qin; McClelland, Michael; Andrews-Polymenis, Helene

    2016-04-01

    Contaminated chicken/egg products are major sources of human salmonellosis, yet the strategies used bySalmonellato colonize chickens are poorly understood. We applied a novel two-step hierarchical procedure to identify new genes important for colonization and persistence ofSalmonella entericaserotype Typhimurium in chickens. A library of 182S.Typhimurium mutants each containing a targeted deletion of a group of contiguous genes (for a total of 2,069 genes deleted) was used to identify regions under selection at 1, 3, and 9 days postinfection in chicks. Mutants in 11 regions were under selection at all assayed times (colonization mutants), and mutants in 15 regions were under selection only at day 9 (persistence mutants). We assembled a pool of 92 mutants, each deleted for a single gene, representing nearly all genes in nine regions under selection. Twelve single gene deletion mutants were under selection in this assay, and we confirmed 6 of 9 of these candidate mutants via competitive infections and complementation analysis in chicks.STM0580,STM1295,STM1297,STM3612,STM3615, andSTM3734are needed forSalmonellato colonize and persist in chicks and were not previously associated with this ability. One of these key genes,STM1297(selD), is required for anaerobic growth and supports the ability to utilize formate under these conditions, suggesting that metabolism of formate is important during infection. We report a hierarchical screening strategy to interrogate large portions of the genome during infection of animals using pools of mutants of low complexity. Using this strategy, we identified six genes not previously known to be needed during infection in chicks, and one of these (STM1297) suggests an important role for formate metabolism during infection. PMID:26857572

  14. Otolith Formation in A Mutant Medaka Fish with A Deficiency in Gravity- Sensing

    Mizuno, R.; Ijiri, K.

    Formation of otoliths in Medaka fish (Oryzias latipes) were studied in the normal (wild-type) fish and in a mutant strain called ha. In the normal fish, two pairs of otoliths (Lapillus and Sagitta) are formed during embryonic development, and the most posterior otolith (Asteriscus) are formed later (about 30 days after hatching). In the mutant strain ha, though Sagittae are formed, Lapilli are absent at hatching. Asterisca are formed normally. Various abnormalities in the formation of Sagittae were detected in ha strain, however, they eventually took normal shapes and positions on the maculae. After hatching, in some ha fish, Lapilli are formed. On 30 days and 40 days after hatching, the appearance of Lapilli were examined by X-ray photography. The results showed that some fis h had a complete pair, some had only one otolith either at the right or left side, and the rest of fish lacked Lapilli completely.

  15. Straight Mutants of Spirillum volutans Can Swim

    Padgett, P. J.; Friedman, M. W.; Krieg, N R

    1983-01-01

    Nonhelical mutant cells of Spirillum volutans ATCC 19554 can swim as fast as the helical cells. Consequently, a helical cell shape is not required for motility of this species, and the function of the polar flagellar fascicles is not merely to cause rotation, and therefore translocation, of the corkscrew-shaped cell.

  16. A dominant semi dwarf mutant in rice

    2002-01-01

    @@ In the winter of 1997, a semi dwarf mutant was found in the F6 population of M9056/ R8018 xuan in Hainan Province. In the spring of 1998, the seeds were sown in Hefei, Anhui Province and the plant height of the population was measured at maturity.

  17. Induced mutants for cereal grain protein improvement

    Out of 17 papers and one summary presented, six dealing with the genetic improvement of seed protein using ionizing radiations fall within the INIS subject scope. Other topics discussed were non-radiation induced mutants used for cereal grain protein improvement

  18. Regulatory Citrate Lyase Mutants of Salmonella typhimurium

    Kulla, Hans G.

    1983-01-01

    Citrate lyase, the key enzyme of anaerobic citrate catabolism, could not be deleted from Salmonella typhimurium. The only class of mutants found had a mode of covalent regulation that strongly resembled the Escherichia coli system: citrate lyase was only active, i.e., acetylated, when a cosubstrate was present.

  19. Regulatory citrate lyase mutants of Salmonella typhimurium.

    Kulla, H G

    1983-01-01

    Citrate lyase, the key enzyme of anaerobic citrate catabolism, could not be deleted from Salmonella typhimurium. The only class of mutants found had a mode of covalent regulation that strongly resembled the Escherichia coli system: citrate lyase was only active, i.e., acetylated, when a cosubstrate was present. PMID:6336740

  20. Molecular Genetic Identification Of Some Flax Mutants

    Five flax genotypes (Linum usitatissimum L.) i.e., commercial cultivar Sakha 2, the mother variety Giza 4 and three mutant types induced by gamma rays, were screened for their salinity tolerance in field experiments (salinity concentration was 8600 and 8300 ppm for soil and irrigation water, respectively). Mutation 6 was the most salt tolerant as compared to the other four genotypes.RAPD technique was used to detect some molecular markers associated with salt tolerance in flax (Mut 6), RAPD-PCR results using 12 random primers exhibited 149 amplified fragments; 91.9% of them were polymorphic and twelve molecular markers (8.1%) for salt tolerant (mutant 6) were identified with molecular size ranged from 191 to 4159 bp and only eight primers successes to amplify these specific markers. Concerning the other mutants, Mut 15 and Mut 25 exhibited 4.3% and 16.2% specific markers, respectively. The induced mutants exhibited genetic similarity to the parent variety were about 51%, 58.3% and 61.1% for Mut 25, Mut 6 and Mut 15, respectively. These specific markers (SM) are used for identification of the induced mutations and it is important for new variety registration.

  1. Characterization of antimicrobial activity against Listeria and cytotoxicity of native melittin and its mutant variants.

    Wu, Xi; Singh, Atul K; Wu, Xiaoyu; Lyu, Yuan; Bhunia, Arun K; Narsimhan, Ganesan

    2016-07-01

    Antimicrobial peptides (AMPs) are relatively short peptides that have the ability to penetrate the cell membrane, form pores leading to cell death. This study compares both antimicrobial activity and cytotoxicity of native melittin and its two mutants, namely, melittin I17K (GIGAVLKVLTTGLPALKSWIKRKRQQ) with a higher charge and lower hydrophobicity and mutant G1I (IIGAVLKVLTTGLPALISWIKRKRQQ) of higher hydrophobicity. The antimicrobial activity against different strains of Listeria was investigated by bioassay, viability studies, fluorescence and transmission electron microscopy. Cytotoxicity was examined by lactate dehydrogenase (LDH) assay on mammalian Caco-2 cells. The minimum inhibitory concentration of native, mutant I17K, mutant G1I against Listeria monocytogenes F4244 was 0.315±0.008, 0.814±0.006 and 0.494±0.037μg/ml respectively, whereas the minimum bactericidal concentration values were 3.263±0.0034, 7.412±0.017 and 5.366±0.019μg/ml respectively. Lag time for inactivation of L. monocytogenes F4244 was observed at concentrations below 0.20 and 0.78μg/ml for native and mutant melittin I17K respectively. The antimicrobial activity against L. monocytogenes F4244 was in the order native>G1I>I17K. Native melittin was cytotoxic to mammalian Caco-2 cells above concentration of 2μg/ml, whereas the two mutants exhibited negligible cytotoxicity up to a concentration of 8μg/ml. Pore formation in cell wall/membrane was observed by transmission electron microscopy. Molecular dynamics (MD) simulation of native and its mutants indicated that (i) surface native melittin and G1I exhibited higher tendency to penetrate a mimic of bacterial cell membrane and (ii) transmembrane native and I17K formed water channel in mimics of bacterial and mammalian cell membranes. PMID:27011349

  2. [Pigment accumulation and functional activity of chloroplasts in common Pisum sativum L. mutants with low chlorophyll level (chlorotica)].

    Ladygin, V G

    2003-01-01

    Pea mutants chlorotica 2004 and 2014 with a low content of chlorophyll were studied. The mutant 2004 has light green leaves and stem, and the mutant 2014 has yellow green leaves and stem. They accumulate approximately 80 and 50% chlorophylls of the parent form of pea Torsdag cv. The content of carotene in carotenoids of the mutant 2004 was much lower, and the accumulation of lutein and violaxanthine was increased. The accumulation of all carotenoids in the mutant 2014 decreased almost proportionally to a decrease in the chlorophyll content. The rate of CO2 evolution in mutant chlorotica 2004 and 2014 was established to be lower. The quantum efficiency of photosynthesis in the mutants was 29-30% lower as compared to the control, and in hybrid plants it was 1.5-2-fold higher. It is assumed that the increase in the activity of the night-time respiration in gas exchange of chlorotica mutants and the drop of photosynthesis lead to a decrease in biomass increment. The results obtained allow us to conclude that the mutation of chlorotica 2004 and 2014 affects the genes controlling the formation and functioning of different components of the photosynthetic apparatus. PMID:12723346

  3. Quadruple zebrafish mutant reveals different roles of Mesp genes in somite segmentation between mouse and zebrafish.

    Yabe, Taijiro; Hoshijima, Kazuyuki; Yamamoto, Takashi; Takada, Shinji

    2016-08-01

    The segmental pattern of somites is generated by sequential conversion of the temporal periodicity provided by the molecular clock. Whereas the basic structure of this clock is conserved among different species, diversity also exists, especially in terms of the molecular network. The temporal periodicity is subsequently converted into the spatial pattern of somites, and Mesp2 plays crucial roles in this conversion in the mouse. However, it remains unclear whether Mesp genes play similar roles in other vertebrates. In this study, we generated zebrafish mutants lacking all four zebrafish Mesp genes by using TALEN-mediated genome editing. Contrary to the situation in the mouse Mesp2 mutant, in the zebrafish Mesp quadruple mutant embryos the positions of somite boundaries were clearly determined and morphological boundaries were formed, although their formation was not completely normal. However, each somite was caudalized in a similar manner to the mouse Mesp2 mutant, and the superficial horizontal myoseptum and lateral line primordia were not properly formed in the quadruple mutants. These results clarify the conserved and species-specific roles of Mesp in the link between the molecular clock and somite morphogenesis. PMID:27385009

  4. Phanerochaete mutants with enhanced ligninolytic activity

    In addition to lignin, the white rot fungus Phanerochaete chrysosporium has the ability to degrade a wide spectrum of recalcitrant organo pollutants in soils and aqueous media. Most of the organic compounds are degraded under ligninolytic conditions with the involvement of the extracellular enzymes, lignin peroxidases, and manganese-dependent peroxidases, which are produced as secondary metabolites triggered by conditions of nutrient starvation (e.g., nitrogen limitation). The fungus and its enzymes can thus provide alternative technologies for bioremediation, bio pulping, bio bleaching, and other industrial applications. The efficiency and effectiveness of the fungus can be enhanced by increasing production and secretion of the important enzymes in large quantities and as primary metabolites under enriched conditions. One way this can be achieved is through isolation of mutants that are deregulated, or are hyper producers or super secretors of key enzymes under enriched conditions. Through UV-light and γ-ray mutagenesis, we have isolated a variety of mutants, some of which produce key enzymes of the ligninolytic system under high-nitrogen growth conditions. One of the mutants, 76UV, produced 272 U of lignin peroxidases enzyme activity/L after 9 d under high nitrogen (although the parent strain does not produce this enzyme under these conditions). The mutant and the parent strains produced up to 54 and 62 U/L, respectively, of the enzyme activity under low nitrogen growth conditions during this period. In some experiments, the mutant showed 281 U/L of enzyme activity under high nitrogen after 17 d

  5. Evaluation of high yielding mungbean mutants

    Mungbean is the second major (Vigna radiata (L.) Wilczek) pulse crop in Pakistan, after chickpea, and is the main pulse crop grown during the spring season in the province of Sindh. Its yield is very low (450 kg/ha) which is mainly due to the non-availability of pure seed of high yield potential genotypes. Keeping in view the importance of induced mutations in all field crops and particularly in the evolution of mungbean cultivars, an induced mutation programme was initiated at AEARC, Tandojam during 1985. Since then a large number of mutants have been developed and are at various stages of evaluation. Among them two mungbean mutants (AEM 6/20 and AEM 32/20) isolated from the treated population of a local cultivar '6601' with 200 Gy gamma-ray treatment gave very encouraging performance in station as well as zonal trials. On the basis of these results they were promoted in the National Trials, where they remained under evaluation for four years during spring as well as summer seasons. The pool data of four consecutive years of both seasons indicated that mutant lines AEM 32/20 and AEM 6/20 produced 1298 and 1246 kg/ha grain yield respectively as compared to the check variety 'NM 121-25' (1055 kg/ha) evolved at NIAB, Faisalabad through induced mutations. The seed yield increase over the check variety ranged from 18-23%. These two mungbean mutants have short stature combined with short duration and synchrony in maturity. Keeping in view the outstanding performance of these mutant lines, variety release proposals are being submitted to the Technical Sub-Committee for approval of varieties and techniques

  6. Developing mutant sunflower lines (Helianthus annuus L.) through induced mutagenesis and study of their combining ability

    Encheva J.; Shindrova P.

    2011-01-01

    Immature sunflower (Helianthus annuus L.) zygotic embryos of sunflower double haploid fertility restorer line 381 R were treated with ultrasound before planting to embryo culture medium. Some mutant plants were isolated and self-pollinated for several generations. New sunflower forms with inherited morphological, biochemical and phytopathological changes were obtained through selection and self-pollination. The genetic changes included 12 morphological and ...

  7. Accumulation of Mutant Neuroserpin Precedes Development of Clinical Symptoms in Familial Encephalopathy with Neuroserpin Inclusion Bodies

    Galliciotti, G; Glatzel, M; Kinter, J.; Kozlov, S V; Cinelli, P.; Rülicke, T; Sonderegger, P.

    2007-01-01

    Intracellular protein deposition due to aggregation caused by conformational alteration is the hallmark of a number of neurodegenerative disorders, including Parkinson's disease, tauopathies, Huntington's disease, and familial encephalopathy with neuroserpin inclusion bodies. The latter is an autosomal dominant disorder caused by point mutations in neuroserpin resulting in its destabilization. Mutant neuroserpin polymerizes and forms intracellular aggregates that eventually lead to neurodegen...

  8. Genome sequence of an Adoxophyes orana granulovirus (AdorGV) occlusion body morphology mutant

    - Genome sequence of an Adoxophyes orana granulovirus (AdorGV) occlusion body morphology mutant Baculoviruses package virus particles in a crystalline matrix of viral protein to form occlusion bodies. Occlusion bodies are used in biological control because the crystalline matrix protects the viral ...

  9. Genetic study of necrotic leaf pea (Pisum sativum L.) mutants

    Four pea (Pisum sativum L.) mutants characterized by necrotic leaves were isolated following mutagenesis. The mutants were shown to have single-gene recessive inheritance, characterized morphologically and for seed production. New mutants 1/704, 1/711M, XV/915 and 2/352 had similar phenotypes, respectively, to previously named mutants dgl (degenerating leaves), nec (necrosis), bls (brown leaf spots) and bls (brown leaf), but no allelism tests were made between the new and the previously reported mutants. Mutants 1/704 and 1/711M were shown to be non-allelic. The mutation in line 2/352 may be useful as a genetic marker

  10. Normal synaptonemal complex and abnormal recombination nodules in two alleles of the Drosophila meiotic mutant mei-W68.

    Carpenter, Adelaide T. C.

    2003-01-01

    The meiotic phenotypes of two mutant alleles of the mei-W68 gene, 1 and L1, were studied by genetics and by serial-section electron microscopy. Despite no or reduced exchange, both mutant alleles have normal synaptonemal complex. However, neither has any early recombination nodules; instead, both exhibit high numbers of very long (up to 2 microm) structures here named "noodles." These are hypothesized to be formed by the unchecked extension of identical but much shorter structures ephemerally...

  11. Mutant p53 exhibits trivial effects on mitochondrial functions which can be reactivated by ellipticine in lymphoma cells

    Wang, Fei; Liu, Jianfeng; Robbins, Delira; Morris, Kerri; Sit, Amos; Liu, Yong-Yu; Zhao, Yunfeng

    2011-01-01

    Increasing evidence has shown that a fraction of the wild-type (wt) form of the tumor suppressor p53, can translocate to mitochondria due to genotoxic stress. The mitochondrial targets of wt p53 have also been studied. However, whether mutant p53, which exists in 50% of human cancers, translocates to mitochondria and affects mitochondrial functions is unclear. In this study, we used doxorubicin, a chemotherapeutic drug, to treat five human lymphoma cell lines with wt, mutant or deficient in p...

  12. Mutants with Enhanced Nitrogenase Activity in Hydroponic Azospirillum brasilense-Wheat Associations

    Pereg Gerk, Lily; Gilchrist, Kate; Kennedy, Ivan R.

    2000-01-01

    The effect of a mutation affecting flocculation, differentiation into cyst-like forms, and root colonization on nitrogenase expression by Azospirillum brasilense is described. The gene flcA of strain Sp7 restored these phenotypes in spontaneous mutants of both strains Sp7 and Sp245. Employing both constitutive pLA-lacZ and nifH-lacZ reporter fusions expressed in situ, the colony morphology, colonization pattern, and potential for nitrogenase activity of spontaneous mutants and flcA Tn5-induce...

  13. Chloroplast ultrastructure in leaves of Cucumis sativus chlorophyll mutant

    Irena Palczewska

    2014-02-01

    Full Text Available The developing and young leaves of Cucumis sativus chlorophyll mutants are yellow, when mature they become green and do not differ in their colour from those of control plants. The mesophyll of yellow leaves contains a diversiform plastid population with a varying degree of defectiveness, which is mainly manifested in the reduction or disorganization of the typical thylakoid system. DNA areas, ribosome-like particles and aggregates of electron-dense material are preserved in the stroma of mutated plastids. Starch grains are deficient. Apart from mutated plastids, chloroplasts with a normal structure, as in control plants, were also observed.The leaf greening process is accompanied by a reconstruction and rearrangement of the inner chloroplast lamellar system and an ability to accumulate starch. However, in the mutant chloroplasts as compared with control-plant ones, an irregular arrangement of grana and reduced number of inter-grana thylakoids can be seen. An osmiophilic substance stored in the stroma of mutated plastids and the vesicles formed from an internal plastid membrane take part in restoration of the membrane system.

  14. Taq DNA Polymerase Mutants and 2'-Modified Sugar Recognition.

    Schultz, Hayley J; Gochi, Andrea M; Chia, Hannah E; Ogonowsky, Alexie L; Chiang, Sharon; Filipovic, Nedim; Weiden, Aurora G; Hadley, Emma E; Gabriel, Sara E; Leconte, Aaron M

    2015-09-29

    Chemical modifications to DNA, such as 2' modifications, are expected to increase the biotechnological utility of DNA; however, these modified forms of DNA are limited by their inability to be effectively synthesized by DNA polymerase enzymes. Previous efforts have identified mutant Thermus aquaticus DNA polymerase I (Taq) enzymes capable of recognizing 2'-modified DNA nucleotides. While these mutant enzymes recognize these modified nucleotides, they are not capable of synthesizing full length modified DNA; thus, further engineering is required for these enzymes. Here, we describe comparative biochemical studies that identify useful, but previously uncharacterized, properties of these enzymes; one enzyme, SFM19, is able to recognize a range of 2'-modified nucleotides much wider than that previously examined, including fluoro, azido, and amino modifications. To understand the molecular origins of these differences, we also identify specific amino acids and combinations of amino acids that contribute most to the previously evolved unnatural activity. Our data suggest that a negatively charged amino acid at 614 and mutation of the steric gate residue, E615, to glycine make up the optimal combination for modified oligonucleotide synthesis. These studies yield an improved understanding of the mutational origins of 2'-modified substrate recognition as well as identify SFM19 as the best candidate for further engineering, whether via rational design or directed evolution. PMID:26334839

  15. Selection of Bacillus subtilis mutants impaired in ammonia assimilation.

    Dean, D R; Aronson, A I

    1980-01-01

    The selection of Bacillus subtilis mutants capable of using D-histidine to fulfill a requirement for L-histidine resulted in mutants with either no glutamate synthase activity or increased amounts of an altered glutamine synthetase.

  16. Serine:glyoxylate aminotransferase mutant of barley

    A photorespiratory mutant of barley (LaPr 85/84), deficient in both of the major peaks of serine:glyoxylate aminotransferase activity detected in the wild type, also lacks serine:pyruvate and asparagine:glyoxylate aminotransferase activities. Genetic analysis of the mutation demonstrated that these three activities are all carried on the same enzyme. The mutant, when placed in air, accumulated a large pool of serine, showed the expected rate (50%) of ammonia release during photorespiration but produced CO2 at twice the wild type rate when it was fed [14C] glyoxylate. Compared with the wild type, LaPr 85/84 exhibited abnormal transient changes in chlorophyll a fluorescence when the CO2 concentration of the air was altered, indicating that the rates of the fluorescence quenching mechanisms were affected in vivo by the lack of this enzyme

  17. Nutritive value of horse gram mutants

    The gamma-rays induced mutation of seeds in horse gram Var. DPL-1 resulted in significant increase in crude protein and crude fibre content in grain. Fat and ash contents were also increased in some of the mutants. Induced mutation, however, did not show beneficial effect on methionine and tryptophan content of the grain. Both these limiting amino acids were deficient in all the genotypes. The mutant ACCK-304 and ACCL-302 appeared to be superior in respect of crude protein content (21.9% and 21.5%), grain yield (15.7 and 15.6 q/ha) and protein yield (3.4 and 3.3 q/ha), respectively. (author)

  18. PNRI mutant variety: sansevieria 'Sword of Ibe'

    Sansevieria 'Sword of Ibe,' registered by the Philippine Nuclear Research Institute as NSIC 2008 Or-66, is a chlorophyll mutant of Sansevieria trifasciata 'Moonshine' developed by treating its suckers or shoots arising from a rhizome with acute gamma radiation from a Cobalt-60 source. The new mutant is identical in growth habit and vigor to Sansevieria 'Moonshine,' also known as Moonglow. Results of this mutation breeding experiment showed that leaf color and flowering were altered by gamma irradiation without changing the other characteristics of the plant. Propagation is true-to-type by separation of sucker and top cutting. The plant is recommended for use as landscaping material and as pot plant for indoor and outdoor use. The leaves may be harvested as cut foliage for Japanese flower arrangements. (author)

  19. Genetic Analysis of Dictyostelium Slug Phototaxis Mutants

    Darcy, P. K.; Wilczynska, Z.; Fisher, P R

    1994-01-01

    Mapping and complementation analysis with 17 phototaxis mutations has established 11 complementation groups phoA-phoK distributed over six linkage groups. Statistical calculations from the complementation data yielded 17 as the maximum likelihood estimate of the number of pho genes assuming all loci are equally mutable. Most of the phototaxis mutants were found to exhibit bimodal phototaxis and all were found to be impaired in positive thermotaxis supporting convergence of the photosensory an...

  20. Endonuclease IV (nfo) mutant of Escherichia coli.

    Cunningham, R P; Saporito, S M; Spitzer, S G; Weiss, B

    1986-01-01

    A cloned gene, designated nfo, caused overproduction of an EDTA-resistant endonuclease specific for apurinic-apyrimidinic sites in DNA. The sedimentation coefficient of the enzyme was similar to that of endonuclease IV. An insertion mutation was constructed in vitro and transferred from a plasmid to the Escherichia coli chromosome. nfo mutants had an increased sensitivity to the alkylating agents methyl methanesulfonate and mitomycin C and to the oxidants tert-butyl hydroperoxide and bleomyci...

  1. Recombination-deficient mutant of Streptococcus faecalis.

    Yagi, Y; Clewell, D B

    1980-01-01

    An ultraviolet radiation-sensitive derivative of Streptococcus faecalis strain JH2-2 was isolated and found to be deficient in recombination, using a plasmid-plasmid recombination system. The strain was sensitive to chemical agents which interact with deoxyribonucleic acid and also underwent deoxyribonucleic acid degradation after ultraviolet irradiation. Thus, the mutant has properties similar to those of recA strains of Escherichia coli.

  2. Induced Dwarf Mutant in Catharanthus roseus with Enhanced Antibacterial Activity

    Verma, A.K.; Singh, R R

    2010-01-01

    Evaluation of an ethyl methane sulphonate-induced dwarf mutant of Catharanthus roseus (L.) G. Don revealed that the mutant exhibited marked variation in morphometric parameters. The in vitro antibacterial activity of the aqueous and alcoholic leaf extracts of the mutant and control plants was investigated against medically important bacteria. The mutant leaf extracts showed enhanced antibacterial activity against all the tested bacteria except Bacillus subtilis.

  3. Induced dwarf mutant in Catharanthus roseus with enhanced antibacterial activity

    Verma A

    2010-01-01

    Full Text Available Evaluation of an ethyl methane sulphonate-induced dwarf mutant of Catharanthus roseus (L. G. Don revealed that the mutant exhibited marked variation in morphometric parameters. The in vitro antibacterial activity of the aqueous and alcoholic leaf extracts of the mutant and control plants was investigated against medically important bacteria. The mutant leaf extracts showed enhanced antibacterial activity against all the tested bacteria except Bacillus subtilis.

  4. Induced Dwarf Mutant in Catharanthus roseus with Enhanced Antibacterial Activity

    Verma, A. K.; Singh, R. R.

    2010-01-01

    Evaluation of an ethyl methane sulphonate-induced dwarf mutant of Catharanthus roseus (L.) G. Don revealed that the mutant exhibited marked variation in morphometric parameters. The in vitro antibacterial activity of the aqueous and alcoholic leaf extracts of the mutant and control plants was investigated against medically important bacteria. The mutant leaf extracts showed enhanced antibacterial activity against all the tested bacteria except Bacillus subtilis. PMID:21695004

  5. Molecular characterization of phycobilisome regulatory mutants of Fremyella diplosiphon.

    Bruns, B U; Briggs, W R; Grossman, A R

    1989-01-01

    Three classes of pigment mutants were generated in Fremyella diplosiphon in the course of electroporation experiments. The red mutant class had high levels of phycoerythrin in both red and green light and no inducible phycocyanin in red light. Thus, this mutant behaved as if it were always in green light, regardless of light conditions. Blue mutants exhibited normal phycoerythrin photoregulation, whereas the inducible phycocyanin was present at high levels in both red- and green-light-grown c...

  6. A Mutant of Mycobacterium smegmatis Defective in Dipeptide Transport

    Bhatt, Achal; Green, Renee; Coles, Roswell; Condon, Michael; Connell, Nancy D.

    1998-01-01

    A mutant of Mycobacterium smegmatis unable to use the dipeptide carnosine (β-alanyl-l-histidine) as a sole carbon or nitrogen source was isolated. Carnosinase activity and the ability to grow on β-Ala and/or l-His were similar in the mutant and the wild type. However, the mutant showed significant impairment in the uptake of carnosine. This study is the first description of a peptide utilization mutant of a mycobacterium.

  7. Vanadate-resistant yeast mutants are defective in protein glycosylation.

    Ballou, L; Hitzeman, R A; Lewis, M. S.; Ballou, C E

    1991-01-01

    Spontaneous recessive orthovanadate-resistant mutants of Saccharomyces cerevisiae were obtained in five complementation groups, and all show defects in protein glycosylation that mimic the previously isolated mnn mutants. Three of the groups are allelic to the known mnn8, mnn9, and mnn10 mutants, whereas the other two groups show other glycosylation defects. The vanadate-resistant phenotype was associated with enhanced hygromycin B sensitivity. The glycosylation phenotypes of the mutants are ...

  8. Evaluation and Characterization of Mutant Cowpea Plants for Enhanced Abiotic Stress Tolerance

    The objective of the project is to use the radiation-induced mutations in cowpea to improve cowpea varieties grown by resource-poor farmers in South Africa. The first aim of the project was to select mutant cowpea plants with improved levels of drought tolerance without alteration to the color of the testa or the growth form. It was demonstrated that it was possible to examine mutant lines at seedling stage in wooden boxes. Mature plants were screened in rain out shelters and physiological traits for drought stress were identified among the lines tested. Roots of mature plants were also assessed and variations observed could be correlated with drought tolerance. The data demonstrated that physiological methods can be used to screen mutants. The yield performance of some mutant lines proved to be outstanding under well-watered, as well as under drought stress conditions. The second aim was to further characterize the most promising mutant lines using molecular and physiological techniques. cDNA-Amplified Fragment Length Polymorphism showed differential gene expression at different time points of drought stress. The sequenced transcript derived fragments (TDF) showed high homology to expressed sequence tags of soybean, with a possible function in cell defense/resistance and most importantly, signal transduction. Reverse transcription PCR using a number of primers from published sequences, as well as from the TDF sequences, validated the differential gene expression obtained from the cDNA-AFLP display. The third aim was to evaluate selected mutants on station and at different communities. On station field trials were conducted at the ARC-VOPI's research farm under dry land as well as irrigation conditions for the last two seasons. The long term plan is to introgress the drought tolerance trait from the best mutant line into drought susceptible South African cultivars grown by resource-poor farmers. (author)

  9. Mutant cultivars of legumes in Poland

    Mutation breeding has played an important role in the improvement of legume cultivars. It is assumed that artificial induction of variability will also be indispensable in the future - for realizing desired ideotypes. This should be true for the pea (one species and three types of usage; discontinuous variation), as well as for the lupin (several species adapted to different soil requirements, a domestication that is not well advanced and about 35-45% protein in the dry seeds). Twelve pea and four broad bean varieties have so far been registered in Poland. Most of the pea varieties have the mutant gene afila, which plays a role in improving one of the most important characters, resistance to lodging. A number of other improved pea varieties resulted from the recombination of mutant genes in crosses with another cultivar. At present, the advanced breeding material of three lupin species and of Phaseolus coccineus are based on mutagen induced variability. The introduction of mutant characters such as self-completing, earliness or a short/stiff stem can easily increase the range of cultivation of these species, both areawise and with regard to marketing. (author). 7 refs, 3 tabs

  10. Grain product of 34 soya mutant lines

    This work was development with the objective of obtaining information of the agronomic behavior of 34 soya mutant lines (R4M18) for human consumption and this way to select the 2 better lines. The genetic materials were obtained starting from the variety ISAAEG-B M2 by means of the application of recurrent radiation with Co60 gammas, to a dose of 350 Gray for the first two generations and both later to 200 Gray and selection during 17 cycles, being obtained the 34 better lines mutants with agronomic characteristic wanted and good flavor. The obtained results were that the mutant lines L25 and L32 produced the major quantity in branches/plant number with 7.5 and 7.25, pods/plant number with 171.25 and 167, grains/plant number with 350.89 and 333.07 and grain product (ton/ha) to 15% of humidity 5.15 and 4.68 ton/ha, respectively. (Author)

  11. Multivariate analysis for selecting apple mutants

    The mutlivariate analysis of four year records on several vegetative and productive traits of twenty-one apple mutants (3 of 'Jonathan', 3 of 'Ozark Gold', 14 of 'Mollie's Delicious', 1 of 'Neipling's Early Stayman)' induced by gamma radiations showed that observation of some traits of one-year-old shoots is the most efficient way to reveal compact growing apple mutants. In particular, basal cross-section area, total length and leaf area resulted the most appropriate parameters, while internode length together with conopy height and width are less appropriate. The most interesting mutants we found are: one of 'Mollie's Delicious for the best balance among tree and fruit traits and for high skin color; one of 'Neipling's Early Stayman' with an earlier and more extensively red colored apple than the original clone. (author)

  12. Incomplete excision repair process after UV-irradiation in MUT-mutants of Proteus mirabillis

    MUT-mutants of P. mirabilis seem to be able to perform the incision step in the course of excision repair. In contrast to the corresponding wildtype strains with MUT-mutants the number of single-strand breaks formed after UV-irradiation is independent of the UV-dose up to about 720 erg/mm2. Incubation in minimal medium over a longer time does not result in completion of excision repair; about 3-6 single-strand breaks in the DNA of these mutants remain open. Likewise, the low molecular weight of the newly synthesized daughter DNA confirms an incompletely proceeding or delayed repair process. As a possible reason for the mutator phenotype an alteration of the DNA-polymerase playing a role in excision and resynthesis steps of excision repair is discussed. (author)

  13. Analysis on expression of gene for flower shape in Dendrobium sonia mutants using differential display technique

    In vitro mutagenesis on Dendrobium Sonia in MINT has produced mutants with wide range of flower form and colour variations. Among the mutants are plants with different flower size and shape. These changes could be caused by alterations to the expression level of the genes responsible for the characteristics. In this studies, Differential Display technique was used to identify and analyse altered gene expression at the mRNA level. Total RNA of the control and mutants were reversed transcribed using three anchored oligo-d T primers. Subsequently, these cDNAs were Pcr amplified in combination with 16 arbitrary primers. The amplified products were electrophoresed side by side on agarose gel. Differentially expressed bands are isolated for further analysis. (Author)

  14. Traits and meiosis in mutant of impatiens balsamina induced by space treatment

    A mutant of Impatiens balsamina was obtained after space induction, and its traits and meiosis were investigated. Characters such as color and form of the mutant expressed great variation. Observation of meiosis showed that most of pollen mother cells were normal in meiosis phase I, except the disproportion of chromosomal segregation, lagging chromosome and dispersal chromosome in anaphase I. Most pollen mother cells developed into microspores tetrad after meiosis, but paraspores also appeared. The number of chromosome in microspore varied from 1 to 21, even more than 30. The shape and size of the microspores fluctuated apparently, and the size of the microspores was in positive correlation to chromosome number. When staining with iodic solution, most of the pollens showed sterility, which was in consistence with the low setting percentage of the mutant plant. It was thought that space induction caused the variation of size, fertility and the abnormal meiosis

  15. Adhesion defective BHK cell mutant has cell surface heparan sulfate proteoglycan of altered properties

    Couchman, J R; Austria, R; Woods, A; Hughes, R C

    1988-01-01

    In the light of accumulating data that implicate cell surface heparan sulfate proteoglycans (HSPGs) with a role in cell interactions with extracellular matrix molecules such as fibronectin, we have compared the properties of these molecules in wild-type BHK cells and an adhesion-defective ricin......-resistant mutant (RicR14). Our results showed that the mutant, unlike BHK cells, cannot form focal adhesions when adherent to planar substrates in the presence of serum. Furthermore, while both cell lines possess similar amounts of cell surface HSPG with hydrophobic properties, that of RicR14 cells had decreased...... sulfation, reduced affinity for fibronectin and decreased half-life on the cell surface when compared to the normal counterpart. Our conclusions based on this data are that these altered properties may, in part, account for the adhesion defect in the ricin-resistant mutant. Whether this results from the...

  16. [Biofilm Formation by the Nonflagellated flhB1 Mutant of Azospirillum brasilense Sp245].

    Shelud'ko, A V; Filip'echeva, Yu A; Shumiliva, E M; Khlebtsov, B N; Burov, A M; Petrova, L P; Katsy, E I

    2015-01-01

    Azospirillum brasilense Sp245 with mixed flagellation are able to form biofilms on various surfaces. A nonflagellated mutant of this strain with inactivated chromosomal copy of the flhB gene (flhB1) was shown to exhibit specific traits at the later stages of biofilm formation on a hydrophilic (glass) surface. Mature biofilms of the flhB1::Omegon-Km mutant Sp245.1063 were considerably thinner than those of the parent strain Sp245. The biofilms of the mutant were more susceptible to the forces of hydrodynamic shear. A. brasilense Sp245 cells in biofilms were not found to possess lateral flagella. Cells with polar flagella were, however, revealed by atomic force microscopy of mature native biofilms of strain Sp245. Preservation of a polar flagellum (probably nonmotile) on the cells of A. brasilense Sp245 may enhance the biofilm stability. PMID:26263623

  17. High yielding early mutant of Mashuri rice variety

    Mashuri mutant was evolved by treating a Malaysian popular rice variety (Mashuri) with gamma rays. This mutant differed from its parent by exhibiting short duration (25 days less), short height (14 cm less) and blast resistance with all other desirable characters of parent type. These desirable changes brought by mutation made the mutant line suitable for the rabi season. (author)

  18. Biological changes in Barley mutants resistant to powdery mildew disease

    physiological studies showed that all kinds of chlorophyll (a), (b) and (a + b) content in infected plant were decreased while, the carotenes pigment were increased. Infection generally reduced total sugars content of all resistant mutants. Infected resistant mutant showed more phenols content and peroxidase, polyphenoloxidase activities than healthy ones of the mutants. (Author)

  19. BIOSORPTION OF CHROMIUM (VI FROM INDUSTRIAL EFFLUENT BY WILD ANDMUTANT TYPE STRAIN OF SACCHAROMYCES CEREVISIAE AND ITS IMMOBILIZED FORM

    K Selvam, K Arungandhi, B Vishnupriya, T Shanmuga priya and M Yamuna

    2013-01-01

    Full Text Available Biosorption of chromium was studied by wild type Saccharomyces cerevisiae strain, mutant strain, immobilized-wild type and mutant strain. Chromium absorption pattern was observed in all experimental conditions. Hexavalent chromium (VI was analyzed by diphenyl carbazide method, by oxidizing the trivalent chromium (III. The percentage efficiency of wild type S. cerevisiae and its mutant strain, immobilized-wild type and mutant strain were 94.8%, 98.7%, 97.4% and 100% respectively. S. cerevisiae mutant strain and their immobilized form was found to be effective in biosorption of chromium (VI than the wild type forms.

  20. Leishmania infantum HSP70-II null mutant as candidate vaccine against leishmaniasis: a preliminary evaluation

    Fresno Manuel

    2011-07-01

    Full Text Available Abstract Background Visceral leishmaniasis is the most severe form of leishmaniasis and no effective vaccine exists. The use of live attenuated vaccines is emerging as a promising vaccination strategy. Results In this study, we tested the ability of a Leishmania infantum deletion mutant, lacking both HSP70-II alleles (ΔHSP70-II, to provide protection against Leishmania infection in the L. major-BALB/c infection model. Administration of the mutant line by either intraperitoneal, intravenous or subcutaneous route invariably leads to the production of high levels of NO and the development in mice of type 1 immune responses, as determined by analysis of anti-Leishmania IgG subclasses. In addition, we have shown that ΔHSP70-II would be a safe live vaccine as immunodeficient SCID mice, and hamsters (Mesocricetus auratus, infected with mutant parasites did not develop any sign of pathology. Conclusions The results suggest that the ΔHSP70-II mutant is a promising and safe vaccine, but further studies in more appropriate animal models (hamsters and dogs are needed to appraise whether this attenuate mutant would be useful as vaccine against visceral leishmaniasis.

  1. Novel memory mutants in Drosophila: Behavioral characteristics of the mutant nemyP153

    Kamysheva Elena A; Bragina Julia V; Iliadi Konstantin G; Kamyshev Nikolai G; Tokmatcheva Elena V; Preat Thomas; Savvateeva-Popova Elena V

    2002-01-01

    Abstract Background Starting from Benzer's initiative, the approach of forward genetics has been widely used to isolate mutations affecting learning and memory. For this aim, mainly the odor-shock conditioning was employed. We have isolated P insertional mutations affecting memory after courtship conditioning – another form of classical conditioning in Drosophila. Here we report the behavioral characteristics of one of these mutants, which we have called nemy (no extended memory). Results The...

  2. Creating Sunflower Mutant Lines (Helianthus Annuus L.) Using Induced Mutagenesis

    Immature sunflower zygotic embryos of sunflower fertility restorer line 374 R were treated with ultrasound and gamma radiation before plating embryos to culture medium. All plants were isolated and self-pollinated for several generations. New sunflower forms with inherited morphological and biochemical changes were obtained. The genetic changes occurring during the mutation procedure included fourteen morphological and biochemical characters. In comparison to the check line 374 R, decreasing of the mean value of the indexes was registered for 33 % of the total number of characters and vise verse, significant increasing was observed for 60 %. Mutation for resistance to the local population of Orobanche cumana race A-E was obtained from the susceptible Bulgarian control line 374 R. Two investigated mutant lines possessed 100 % resistance to Orobanche and stable inheritance in the next generations. Our results showed that induced mutagenesis in sunflower can be successfully used to develop new lines useful for heterosis breeding

  3. Selective isolation of UV-sensitive Rhodopseudomonas sphaeroides mutants

    Application of penicillin selection method after UV irradiation (λ=254 nm) increases by an order efficiency of mutant selection sensible to ulraviolet radiation (uvs mutants), phototrophic bacterium Rhodopseudomonas sphaeroides induced with nitrosomethylurea (NMM). Over 30% of uvs mutants produced by means of this method possessed increased sensitivity not only to short-wave (sUV, λ=254 nm) but also to long-wave (lUV, λ>280 nm) UV radiations. No correlation in the degree of sensitivity of uvs mutants to sUV and lUV irradiations is discovered. Mutants, which are high-sensitive to lethal effect of lUV, are separated

  4. Form Matters

    Hedegaard Larsen, Morten

    2010-01-01

    This thesis investigates the reasons for our (in the Western World) preference for shopping (for food) in supermarkets? What social and performative historical developments might explain this preference? And what are the consequences of this preference? Historical descriptions of the performativity of the food market from the first Agora’s to the supermarkets of the 21st century as well as from theatre’s and Western performance spaces will form the comparative analytical basis, together wi...

  5. Economic impact of mutant varieties in India

    The first attempts to induce mutations in India were made in the 1930s, and a few spontaneous mutants were released as new cultivars during the 1940s. Sustained efforts to use induced mutations for the genetic improvement of crop plants were initiated during the late 1950s. Over the past three decades more than 200 new cultivars have been released. They cover a wide range of crops: cereals, grain legumes, oilseeds, fibre crops, vegetables and ornamentals. Mutation breeding has been most successful in self-pollinated crops and in vegetatively propagated ornamentals. The approved cultivars are grown over a large area in different parts of the country, providing both monetary and social benefits. Some of the mutant cultivars released in 1969 are still included in the list of approved cultivars. Besides these successes, there are an equal number of others where the desired results could not be obtained or the mutants and their derivatives failed to achieve the yield/quality levels acceptable for commercial release. Mutation breeding as a tool is widely accepted and used in breeding programmes. A number of new cellular and molecular techniques are now available for the genetic improvement of crop plants. The cellular techniques remain random chance events, similar to induced mutations. Some of the in vitro culture techniques can enhance the efficiency of mutation breeding. Because of its relative simplicity and low cost, mutagenic treatment of seeds and other parts of the plant remains a useful tool for isolating the desired variants in breeding programmes. (author). 16 refs, 8 tabs

  6. A photorespiratory mutant of Chlamydomonas reinhardtii

    A mutant strain of Chlamydomonas reinhardtii, designated 18-7F, has been isolated and characterized. 18-7F requires a high CO2 concentration for photoautrophic growth in spite of the apparent induction of a functional CO2 concentrating mechanism in air-adapted cells. In 2% O2 the photosynthetic characteristics of 18-7F and wild type are similar. In 21% O2, photosynthetic O2 evolution is severely inhibited in the mutant by preillumination in limiting CO2, although the apparent photosynthetic affinity for inorganic carbon is similar in preilluminated cells and in cells incubated in the dark prior to O2 evolution measurements. Net CO2 uptake is also inhibited when the cells are exposed to air (21% O2, 0.035% CO2, balance N2) for longer than a few minutes. [14C]Phosphoglycolate accumulates within 5 minutes of photosynthetic 14CO2 fixation in cells of 18-7F. Phosphoglycolate does not accumulate in wild type. Phosphoglycolate phosphatase activity in extracts from air-adapted cells of 18-7F is 10 to 20% of that in wild-type Chlamydomonas. The activity of phosphoglycolate phosphatase in heterozygous diploids is intermediate between that of homozygous mutant and wild-type diploids. It was concluded that the high-CO2 requiring phenotype in 18-7F results from a phosphoglycolate phosphatase deficiency. Genetic analyses indicate that this deficiency results from a single-gene, nuclear mutation. We have named the locus pgp-1

  7. Aggregation of ALS-linked FUS mutant sequesters RNA binding proteins and impairs RNA granules formation

    Takanashi, Keisuke; Yamaguchi, Atsushi, E-mail: atsyama@restaff.chiba-u.jp

    2014-09-26

    Highlights: • Aggregation of ALS-linked FUS mutant sequesters ALS-associated RNA-binding proteins (FUS wt, hnRNP A1, and hnRNP A2). • Aggregation of ALS-linked FUS mutant sequesters SMN1 in the detergent-insoluble fraction. • Aggregation of ALS-linked FUS mutant reduced the number of speckles in the nucleus. • Overproduced ALS-linked FUS mutant reduced the number of processing-bodies (PBs). - Abstract: Protein aggregate/inclusion is one of hallmarks for neurodegenerative disorders including amyotrophic lateral sclerosis (ALS). FUS/TLS, one of causative genes for familial ALS, encodes a multifunctional DNA/RNA binding protein predominantly localized in the nucleus. C-terminal mutations in FUS/TLS cause the retention and the inclusion of FUS/TLS mutants in the cytoplasm. In the present study, we examined the effects of ALS-linked FUS mutants on ALS-associated RNA binding proteins and RNA granules. FUS C-terminal mutants were diffusely mislocalized in the cytoplasm as small granules in transiently transfected SH-SY5Y cells, whereas large aggregates were spontaneously formed in ∼10% of those cells. hnRNP A1, hnRNP A2, and SMN1 as well as FUS wild type were assembled into stress granules under stress conditions, and these were also recruited to FUS mutant-derived spontaneous aggregates in the cytoplasm. These aggregates stalled poly(A) mRNAs and sequestered SMN1 in the detergent insoluble fraction, which also reduced the number of nuclear oligo(dT)-positive foci (speckles) in FISH (fluorescence in situ hybridization) assay. In addition, the number of P-bodies was decreased in cells harboring cytoplasmic granules of FUS P525L. These findings raise the possibility that ALS-linked C-terminal FUS mutants could sequester a variety of RNA binding proteins and mRNAs in the cytoplasmic aggregates, which could disrupt various aspects of RNA equilibrium and biogenesis.

  8. Aggregation of ALS-linked FUS mutant sequesters RNA binding proteins and impairs RNA granules formation

    Highlights: • Aggregation of ALS-linked FUS mutant sequesters ALS-associated RNA-binding proteins (FUS wt, hnRNP A1, and hnRNP A2). • Aggregation of ALS-linked FUS mutant sequesters SMN1 in the detergent-insoluble fraction. • Aggregation of ALS-linked FUS mutant reduced the number of speckles in the nucleus. • Overproduced ALS-linked FUS mutant reduced the number of processing-bodies (PBs). - Abstract: Protein aggregate/inclusion is one of hallmarks for neurodegenerative disorders including amyotrophic lateral sclerosis (ALS). FUS/TLS, one of causative genes for familial ALS, encodes a multifunctional DNA/RNA binding protein predominantly localized in the nucleus. C-terminal mutations in FUS/TLS cause the retention and the inclusion of FUS/TLS mutants in the cytoplasm. In the present study, we examined the effects of ALS-linked FUS mutants on ALS-associated RNA binding proteins and RNA granules. FUS C-terminal mutants were diffusely mislocalized in the cytoplasm as small granules in transiently transfected SH-SY5Y cells, whereas large aggregates were spontaneously formed in ∼10% of those cells. hnRNP A1, hnRNP A2, and SMN1 as well as FUS wild type were assembled into stress granules under stress conditions, and these were also recruited to FUS mutant-derived spontaneous aggregates in the cytoplasm. These aggregates stalled poly(A) mRNAs and sequestered SMN1 in the detergent insoluble fraction, which also reduced the number of nuclear oligo(dT)-positive foci (speckles) in FISH (fluorescence in situ hybridization) assay. In addition, the number of P-bodies was decreased in cells harboring cytoplasmic granules of FUS P525L. These findings raise the possibility that ALS-linked C-terminal FUS mutants could sequester a variety of RNA binding proteins and mRNAs in the cytoplasmic aggregates, which could disrupt various aspects of RNA equilibrium and biogenesis

  9. Comparative studies on production of Glutamic acid using wild type, mutants, immobilized cells and immobilized mutants of Corynebacterium glutamicum

    Hajera Tabassum,

    2011-05-01

    Full Text Available In the present study comparative studies were carried out on glutamic acid production with wild type cells, mutants, immobilized cells and immobilized mutants of Corynebacerium glutamicum. Immobilization was carried out by sodium alginate method; physical mutagenesis was performed by U.V irradiation and chemical mutagenesis with nitrosoguanidine. Five physical mutants and five chemical mutants were selected for study. Fermentation was carried out for a period of six days at 300C at 200 rpm. Highest amount of glutamic acid was produced with immobilized chemical mutants.

  10. Radiation-Sensitive Mutants of CAENORHABDITIS ELEGANS

    Hartman, Philip S.; Herman, Robert K.

    1982-01-01

    Nine rad (for abnormal radiation sensitivity) mutants hypersensitive to ultraviolet light were isolated in the small nematode Caenorhabditis elegans. The mutations are recessive to their wild-type alleles, map to four of the six linkage groups in C. elegans and define nine new games named rad-1 through rad-9. Two of the mutants—rad-1 and rad-2—are very hypersensitive to X rays, and three—rad-2, rad-3 and rad-4—are hypersensitive to methyl methanesulfonate under particular conditions of exposu...

  11. Enrichment of Auxotrophic Mutants in Streptomyces griseus

    Werner, Rolf G.; Demain, Arnold L.

    1980-01-01

    A method for the isolation and enrichment of tryptophan auxotrophic mutants of the indolmycin-producing strain Streptomyces griseus ATCC 12648 was developed, using penicillin selection. With UV irradiation of 2.2 × 104 μW cm−2, a mutation rate to tryptophan auxotrophy of 5.6 × 10−4 was achieved. With 300 μg ml−1 of penicillin G, an enrichment of tryptophan auxotrophs of about 1,000-fold was attained. Approximately 40% of all survivors were tryptophan auxotrophs.

  12. Automorphic Forms

    von Essen, Flemming Brændgaard

    Hecke characters in the points 4 and 6. It is well known, that all zeros of the Eisenstein series Ek wrt. SL2(Z) in the standard fundamental domain has modulus 1. We show that this is also true for #n Ek, where # is a certain differential operator. We then proceed to study logarithms of multiplier...... systems. For automorphic forms wrt. Hecke triangle groups and Fuchsian groups with no elliptic elements and genus 0, we show that some logarithms of multiplier systems can be interpreted as a linking number. Finally we show a "twisted" version of the prime geodesics theorem, and logarithms of multiplier...

  13. A lipopolysaccharide (LPS)-resistant mutant isolated from a macrophagelike cell line, J774.1, exhibits an altered activated-macrophage phenotype in response to LPS.

    Amano, F; Akamatsu, Y

    1991-06-01

    A bacterial lipopolysaccharide (LPS)-resistant mutant was isolated from murine macrophagelike cell line J774.1. The mutant showed selective resistance to LPS and lipid A and was almost 10(5)- to 10(6)-fold more resistant than the parent; it grew even in the presence of 1 mg of Escherichia coli O55:B5 LPS per liter, whereas the parent did not grow with less than 10 ng of LPS per milliliter. We next examined the mutant for activation of various functions of macrophages on LPS treatment. This LPS-resistant mutant secreted interleukin-1 and tumor necrosis factor almost as effectively as the parent did. The mutant cells also changed transiently from a round to a spread form; however, they became round again afterwards. The mutant cells secreted less arachidonic acid in response to LPS. These results also suggest that this LPS-resistant mutant responds to LPS and shows activation of some macrophage functions. However, this mutant did not exhibit elevation of O2- generation or H2O2 generation after LPS treatment. Also, treatment of the mutant cells with murine recombinant gamma interferon was partly able to correct the defect in O(2-)-generating activity in response to LPS, suggesting that this defect is probably due to some of the LPS signal pathways. This implies that there is some correlation between O2- metabolism in LPS-activated macrophages and decreases in cell growth and viability. PMID:1645329

  14. Auxin physiology of the tomato mutant diageotropica

    Daniel, S. G.; Rayle, D. L.; Cleland, R. E.

    1989-01-01

    The tomato (Lycopersicon esculentum, Mill.) mutant diageotropica (dgt) exhibits biochemical, physiological, and morphological abnormalities that suggest the mutation may have affected a primary site of auxin perception or action. We have compared two aspects of the auxin physiology of dgt and wild-type (VFN8) seedlings: auxin transport and cellular growth parameters. The rates of basipetal indole-3-acetic acid (IAA) polar transport are identical in hypocotyl sections of the two genotypes, but dgt sections have a slightly greater capacity for IAA transport. 2,3,5-Triiodobenzoic acid and ethylene reduce transport in both mutant and wild-type sections. The kinetics of auxin uptake into VFN8 and dgt sections are nearly identical. These results make it unlikely that an altered IAA efflux carrier or IAA uptake symport are responsible for the pleiotropic effects resulting from the dgt mutation. The lack of auxin-induced cell elongation in dgt plants is not due to insufficient turgor, as the osmotic potential of dgt cell sap is less (more negative) than that of VFN8. An auxin-induced increase in wall extensibility, as measured by the Instron technique, only occurs in the VFN8 plants. These data suggest dgt hypocotyls suffer a defect in the sequence of events culminating in auxin-induced cell wall loosening.

  15. Indy mutants: live long and prosper

    Stewart eFrankel

    2012-02-01

    Full Text Available Indy encodes the fly homologue of a mammalian transporter of di and tricarboxylatecomponents of the Krebs cycle. Reduced expression of fly Indy or two of the C. elegansIndy homologs leads to an increase in life span. Fly and worm tissues that play key roles inintermediary metabolism are also the places where Indy genes are expressed. One of themouse homologs of Indy (mIndy is mainly expressed in the liver. It has been hypothesizedthat decreased INDY activity creates a state similar to caloric restriction (CR. Thishypothesis is supported by the physiological similarities between Indy mutant flies on highcalorie food and control flies on CR, such as increased physical activity and decreases inweight, egg production, triglyceride levels, starvation resistance, and insulin signaling. Inaddition, Indy mutant flies undergo changes in mitochondrial biogenesis also observed inCR animals. Recent findings with mIndy knockout mice support and extend the findingsfrom flies. mIndy-/- mice display an increase in hepatic mitochondrial biogenesis, lipidoxidation and decreased hepatic lipogenesis. When mIndy-/- mice are fed high calorie foodthey are protected from adiposity and insulin resistance. These findings point to INDY as apotential drug target for the treatment of metabolic syndrome, type 2 diabetes and obesity.

  16. Isolation of mouse cell proteoglycan mutants

    The sulfated proteoglycans on the surface of cultured mammalian cells have been implicated in a variety of phenomena. To obtain more direct evidence for the role of these molecules in specific cellular functions, they are isolating mutants that produce altered sulfated proteoglycans from a cloned line of Swiss mouse 3T3 cells. This cell type was selected because it exhibits contact inhibition of growth and there is extensive information on its' cell surface and extracellular proteoglycans and other glycoproteins. Cells were chemically mutagenized and subjected to one or more cycles of radiation suicide in the presence of 35S-sulfate. By replica plating, 150 clones, which appear to incorporate abnormal amounts of 35S-sulfate, have been selected. After recloning three times via the replica plating technique, the proteoglycans of 29 clones have thus far been analyzed. They have identified four clones which appear to make altered amounts of either cell surface heparan sulfate or chondroitin sulfate. The biochemical bases for the altered levels of the proteoglycans are under study. Of particular interest, however, is the fact that in this limited collection of mutants the chemical alterations correlate with specific altered cellular morphologies

  17. Induction of drought tolerant mutants of rice

    The ultimate goal of crop breeding is to develop varieties with a high yield potential and desirable agronomic characteristics. In Egypt, the most important qualities sought by breeders have been high yield potential, resistance to major diseases and insects, and improved grain and eating quality. However, breeding efforts should concentrate on varieties with the potential to minimize yield losses under unfavorable conditions such as drought, and to maximize yields when conditions are favorable. Rice (Oryza sativa L.) in Egypt is completely irrigated and a significant portion of the rice cultivated area is subject to water deficit resulting from an inadequate or insufficient irrigation supply. Drought tolerance is a complex trait in that it results from the interaction of histological and physiological characters of plant with environmental factors, both above-ground and under-ground. Accordingly, root characters are closely related to drought tolerance. Little attention has been paid in Egyptian breeding programs to root characters and their relation to shoot characters. Furthermore, induced mutations are considered as one of the most important methods to induce useful mutants, especially with improved root characters, to overcome the drought problem. The present investigation aimed to study the effect of different doses of gamma rays on several characters of three Egyptian rice varieties, i.e. 'Giza 171', 'Giza 175' and 'Giza 176' and to induce one or more mutants possessing drought tolerance

  18. Flower morphology of Dendrobium Sonia mutants

    Dendrobium Sonia is a commercial hybrid which is popular as cut flower and potted plant in Malaysia. Variability in flower is important for new variety to generate more demands and choices in selection. Mutation induction is a tool in creating variability for new flower color and shape. In vitro cultures of protocorm-like bodies (PLBs) were exposed to gamma ray at dose 35 Gy. Phenotypic characteristics of the flower were observed at fully bloomed flower with emphasis on shape and color. Approximately 2000 regenerated irradiated plants were observed and after subsequent flowering, 100 plants were finally selected for further evaluation. Most of the color and shape changes are expressed in different combinations of petal, sepal and lip of the flower. In this work, 11 stable mutants were found different at flower phenotype as compared to control. Amongst these, four mutant varieties with commercial potential has been named as Dendrobium 'SoniaKeenaOval', Dendrobium 'SoniaKeenaRadiant', Dendrobium 'SoniaKeenaHiengDing' and Dendrobium 'Sonia KeenaAhmadSobri'. In this paper, variations in flower morphology and flower color were discussed, giving emphasis on variations in flower petal shape. (author)

  19. Auxin physiology of the tomato mutant diageotropical

    Daniel, S.G.; Rayle, D.L. (San Diego State Univ., CA (USA)); Cleland, R.E. (Univ. of Washington, Seattle (USA))

    1989-11-01

    The tomato (Lycopersicon esculentum, Mill.) mutant diageotropica (dgt) exhibits biochemical, physiological, and morphological abnormalities that suggest the mutation may have affected a primary site of auxin perception or action. We have compared two aspects of the auxin physiology of dgt and wild-type (VFN8) seedlings: auxin transport and cellular growth parameters. The rates of basipetal indole-3-acetic acid (IAA) polar transport are identical in hypocotyl sections of the two genotypes, but dgt sections have a slightly greater capacity for IAA transport. 2,3,5-Triiodobenzoic acid and ethylene reduce transport in both mutant and wild-type sections. The kinetics of auxin uptake into VFN8 and dgt sections are nearly identical. These results make it unlikely that an altered IAA efflux carrier or IAA uptake symport are responsible for the pleiotropic effects resulting from the dgt mutation. The lack of auxin-induced cell elongation in dgt plants is not due to insufficient turgor, as the osmotic potential of dgt cell sap is less (more negative) than that of VFN8. An auxin-induced increase in wall extensibility, as measured by the Instron technique, only occurs in the VFN8 plants. These data suggest dgt hypocotyls suffer a defect in the sequence of events culminating in auxin-induced cell wall loosening.

  20. nitrate non-utilizing (nit mutants

    D. Aiuchi

    2008-01-01

    Full Text Available Mycotal and Vertalec are mass-produced fungal strains for insect control. Strain B-2, which was isolated in Japan, has high epiphytic ability on cucumber leaves. Protoplast fusion was performed using these strains of Verticillium lecanii to obtain new strains possessing useful characteristics as biological control agents (BCAs. We used nit mutants for visually selecting the protoplasts. Hybrid strains were subjected to molecular analysis using the polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLPs and arbitrarily primed-PCR (AP-PCR in order to determine protoplast fusion and/or genetic recombination. We detected 126, 44, and 4 hybrid strains from the combinations of Vertalec × Mycotal, B-2 × Mycotal, and B-2 × Vertalec, respectively. Morphological characteristics of hybrid strains differed from those of their parental nit mutants. Protoplast fusion of hybrid strains was confifi rmed in genomic DNA, but not in mitochondrial DNA (mtDNA. A uniform biased tendency of the DNA banding pattern was observed depending on the combination of parental strains. The molecular analysis also revealed genetic recombination. These results showed a novel method for producing hybrid strains of the entomopathogenic fungus V. lecanii.

  1. Neurobehavioral Mutants Identified in an ENU Mutagenesis Project

    Cook, Melloni N. [University of Memphis; Dunning, Jonathan P [University of Memphis; Wiley, Ronald G [Vanderbilt University and Veterans Administration, Nashville, TN; Chesler, Elissa J [ORNL; Johnson, Dabney K [ORNL; Goldowitz, Daniel [University of Tennessee Health Science Center, Memphis

    2007-01-01

    We report on a behavioral screening test battery that successfully identified several neurobehavioral mutants among a large-scale ENU-mutagenized mouse population. Large numbers of ENU mutagenized mice were screened for abnormalities in central nervous system function based on abnormal performance in a series of behavior tasks. We developed and employed a high-throughput screen of behavioral tasks to detect behavioral outliers. Twelve mutant pedigrees, representing a broad range of behavioral phenotypes, have been identified. Specifically, we have identified two open field mutants (one displaying hyper-locomotion, the other hypo-locomotion), four tail suspension mutants (all displaying increased immobility), one nociception mutant (displaying abnormal responsiveness to thermal pain), two prepulse inhibition mutants (displaying poor inhibition of the startle response), one anxiety-related mutant (displaying decreased anxiety in the light/dark test), and one learning and memory mutant (displaying reduced response to the conditioned stimulus) These findings highlight the utility of a set of behavioral tasks used in a high throughput screen to identify neurobehavioral mutants. Further analysis (i.e., behavioral and genetic mapping studies) of mutants is in progress with the ultimate goal of identification of novel genes and mouse models relevant to human disorders as well as the identification of novel therapeutic targets.

  2. Serrated leaf mutant in mungbean (Vigna radiata (L) Wilczek)

    Dry dormant seeds of mungbean (Vigna radiata (L) Wilczek) were treated with gamma rays (15, 30 and 60 kR). The serrated leaf mutation was noticed in M2 of cultivar Pak 32 treated with 60 kR. Cf 14 plants, 3 showed the altered leaf structure and the others were normal. The feature of this mutant was the deep serration of leaflet margins. The mutant had large thick leaflets with prominent venation. The mutant bred true in the M3 and successive generation. Details of the morphological characteristics of the mutant are presented. The mutant exhibited slower growth particularly during the early stages of development, flowered later and attained shorter height. There was an increase in the number of pods, in seed weight and in seed protein content, but number of seed per pod was considerably reduced. The seed coat colour showed a change from green to yellowish green. In the mutant's flowers the stamina were placed much below the stigma level and the stigma sometimes protruded the corolla. Outcrossing of 4% recorded in some of the mutant lines revealed a reduced cleistogamy. The low number of seeds per pod in the mutant could be due to reduced pollen fertility. The mutant behaved as monogenic recessive. The symbols SL/sl are proposed for this allelic pair. The mutant may have use as a green manure crop because of its large foliage and for the breeders as a genetic marker

  3. Inferring PDZ domain multi-mutant binding preferences from single-mutant data.

    Elena Zaslavsky

    Full Text Available Many important cellular protein interactions are mediated by peptide recognition domains. The ability to predict a domain's binding specificity directly from its primary sequence is essential to understanding the complexity of protein-protein interaction networks. One such recognition domain is the PDZ domain, functioning in scaffold proteins that facilitate formation of signaling networks. Predicting the PDZ domain's binding specificity was a part of the DREAM4 Peptide Recognition Domain challenge, the goal of which was to describe, as position weight matrices, the specificity profiles of five multi-mutant ERBB2IP-1 domains. We developed a method that derives multi-mutant binding preferences by generalizing the effects of single point mutations on the wild type domain's binding specificities. Our approach, trained on publicly available ERBB2IP-1 single-mutant phage display data, combined linear regression-based prediction for ligand positions whose specificity is determined by few PDZ positions, and single-mutant position weight matrix averaging for all other ligand columns. The success of our method as the winning entry of the DREAM4 competition, as well as its superior performance over a general PDZ-ligand binding model, demonstrates the advantages of training a model on a well-selected domain-specific data set.

  4. Mutant radiation-resistance alleles from the Escherichia coli Gamr444 mutant: Cloning and preliminary characterization

    Mutant alleles Gamr, which are able to increase the resistance to radiation of Escherichia coli wild-type cells, were cloned from the hyperradioresistant mutant Gamr444 on plasmid mini-Mu-vector MudII4042. The influence of recombinant plasmids on the sensitivity of wild-type and mutant (recA and htpR) cells to γ-irradiation was studied. It was shown that the enhanced resistance of the Gamr444 strain to radiation was caused by mutations of two different classes, dominant and recessive. The cloned recessive mutation gamr12 increases resistance to radiation only after homogenotization, that is, radiation-induced transfer from the plasmid to the chromosome, and it imposes constitutive expression of the heat-shock promoter htpG. Dominant mutant gamr alleles are active in the trans-position. A mutation-insertion into a chromosomal gene impaired by one of the dominant mutations, gamr18, was constructed. The insertion causes drastic cell radiosensitization on the recBC sbcB background and probably disturbs the RecF pathway of recombination and repair. Dominant plasmids of the second type lead to the RecA-independent inhibition of DNA postirradiation degradation. The radioprotective action of recessive and dominant gamr mutations is additive

  5. Evaluation and characterisation of mutant cowpea plants for enhanced abiotic stress tolerance

    The objective of the project is to use the radiation induced mutations in cowpea to improve cowpea varieties grown by resource-poor farmers in South Africa. The first aim project was to select cowpea plants with improved levels of drought tolerance without alteration to the colour of the testa or the growth form. It was demonstrated that it was possible to examine mutant lines at seedling stage in wooden boxes. Mature plants were screened in rain out shelters and physiological traits for drought stress were identified among the lines tested. Roots of mature plants were also assessed and variation observed could be correlated with drought tolerance. The data demonstrated that physiological methods can be used to screen mutants. The yield performance of some mutant lines proved to be outstanding under well watered, as well as under drought stress conditions. The second aim was to further characterise the most promising mutant lines using molecular and physiologically techniques. cDNA-Amplified Fragment Length Polymorphism showed differential gene expression at different time points of drought stress.The sequenced transcript derived fragments (TDF) showed high homology to expressed sequence tags of soybean, with a possible function in cell defence/resistance and most importantly, signal transduction. Reverse transcription PCR using a number of primers from published sequences, as well as from the TDF sequences, validated the differential gene expression obtained from the cDNA-AFLP display. The third aim was to evaluate selected mutants on station and at different communities. On station field trials were conducted at the ARC-VOPI's research farm under dryland as well as irrigation conditions for the last two seasons. The long term plan is to introgress the drought tolerance trait from the best mutant line into drought susceptible South African cultivars grown by resource-poor farmers. (author)

  6. Understanding the Molecular Mechanisms of Disease Resistance Using Rice Mutants

    The Pi-ta gene in rice has been used to prevent the rice blast disease worldwide for several decades. In the US, Pi-ta was introgressed from a landrace indica variety, Tetep, into several tropical japonica cultivars including Katy. Pi-ta is predicted to encode a cytoplasmic receptor that directly binds to the elicitor produced by the pathogen avirulence gene AVR-Pita for initiating resistance. Katy, expressing resistance conditioned by Pi-ta, Pi-ta2, and Pi-ks to the races of M. oryzae, IB1, IB45, IB49, IB54, IC17, IH1, IE1, and IG1, was treated with mutagens, fast neutrons and ethyl methyl sulfate (EMS). Six mutants with enhanced resistance or susceptibility were identified by screening M2 seedlings derived from 15,000 M1 plants. Among them, M562, induced by EMS, is a lesion mimic mutant (named as LMM1) that produces spontaneous hypersensitive cell death. This rapid cell death was quickly induced using detached leaves at and near the site of inoculation by the virulent race IE1k and more slowly induced when inoculated with the avirulent isolate IB49. Similar hypersensitive cell death was observed after detached leaves were inoculated with the fungus Rhizoctonia solani, the causal agent of rice sheath blight disease. Hypersensitive cell death is known to be a form of the defense response. Thus, we suggest that LMM1 has enhanced resistance to both rice blast and sheath blight pathogens. Although the Pi-ta gene in rice provides resistance to the races, IB1, IB45, IB49, IC17, IH1, IE1, IB54, and IG1, the mutant M2354 was observed to be susceptible to all races except IB54 although there was no change in the Pi-ta DNA sequence. Expression of Pi-ta in M2354 was also similar to that of the parent examined by qRT-PCR. Thus, mutations in M2354 likely occurred at a new locus named as Ptr(t). Another four lines were determined to be near isogenic lines at a 9 megabase genomic region spanning the Pi-ta locus of Katy. Progress on characterizing these six genetic stocks is

  7. The induced SDI mutant and other useful mutant genes in modern rice varieties

    Induced mutation was accelerated in the USA with the release in California in 1976 of Calrose 76, the nation's first semidwarf table rice variety. Success was due not only to induction of mutants but also to their evaluation and integration into cross-breeding programs. Thus the evaluation of Calrose 76 showed that its sdl gene was allelic to sdl in the indica Green Revolution varieties DGWG, TN(1) and IR8, and that semidwarfism conferred a yield advantage of 14% over the 6mt/ha yield level of the tall japonicas. Immediate integration of the Calrose 76 source of semidwarfism into cross-breeding has resulted in 25 semidwarf varieties that trace their ancestral source of semidwarfism to Calrose 76: 13 in California, 10 in Australia, and 2 in Egypt. Calrose 76 ancestry also appears in the pedigrees of numerous additional California cultivars derived from crossing the Calrose 76 source with the IR8 source of semidwarfism. In the late 1990s 12 semidwarf mutants were induced in tall tropical japonica varieties at the Dale Bumpers National Rice Research Center in Arkansas. The semidwarfing gene in each of these 12 germplasms was found to be nonallelic to sdl. Although selected for productivity, none of the 12 consistently showed yield increases typical of sd1 sources. The sdl source, whether from induced mutation or from the indica source, is truly associated with enhanced productivity. Other induced mutants were found for early flowering, low phytic acid, giant embryo, and marker genes such as gold leaf and extreme dwarfism. The early flowering mutants were recovered in temperate japonicas, in tropical japonicas, and most recently in indicas. The early flowering indica mutants are quite interesting since they provide high yielding or blast disease-resistant indica germplasm which will mature in the USA. (author)

  8. The Induced sd1 Mutant and Other Useful Mutant Genes in Modern Rice Varieties

    Induced mutation was accelerated in the USA with the release in California in 1976 of Calrose 76, the nation's first semidwarf table rice variety. Success was due not only to induction of mutants but also to their evaluation and integration into cross-breeding programmes. Thus the evaluation of Calrose 76 showed that its sd1 gene was allelic to sd1 in the indica Green Revolution varieties DGWG, TN(1) and IR8, and that semidwarfism conferred a yield advantage of 14% over the 6mt/ha yield level of the tall japonicas. Immediate integration of the Calrose 76 source of semidwarfism into cross-breeding has resulted in 25 semidwarf varieties that trace their ancestral source of semidwarfism to Calrose 76: 13 in California, 10 in Australia, and 2 in Egypt. Calrose 76 ancestry also appears in the pedigrees of numerous additional California cultivars derived from crossing the Calrose 76 source with the IR8 source of semidwarfism. In the late 1990s 12 semidwarf mutants were induced in tall tropical japonica varieties at the Dale Bumpers National Rice Research Center in Arkansas. The semidwarfing gene in each of these 12 germplasms was found to be nonallelic to sd1. Although selected for productivity, none of the 12 consistently showed yield increases typical of sd1 sources. The sd1 source, whether from induced mutation or from the indica source, is truly associated with enhanced productivity. Other induced mutants were found for early flowering, low phytic acid, giant embryo, and marker genes such as gold leaf and extreme dwarfism. The early flowering mutants were recovered in temperate japonicas, in tropical japonicas, and most recently in indicas. The early flowering indica mutants are quite interesting since they provide high-yielding or blast disease-resistant indica germplasm which will mature in the USA. (author)

  9. Boc modifies the holoprosencephaly spectrum of Cdo mutant mice

    Wei Zhang

    2011-05-01

    Holoprosencephaly (HPE is caused by a failure to form the midline of the forebrain and/or midface. It is one of the most common human birth defects, but clinical expression is extremely variable. HPE is associated with mutations in the sonic hedgehog (SHH pathway. Mice lacking the Shh pathway regulator Cdo (also called Cdon display HPE with strain-dependent penetrance and expressivity, implicating silent modifier genes as one cause of the variability. However, the identities of potential HPE modifiers of this type are unknown. We report here that whereas mice lacking the Cdo paralog Boc do not have HPE, Cdo;Boc double mutants on a largely Cdo-resistant genetic background have lobar HPE with strong craniofacial anomalies and defects in Shh target gene expression in the developing forebrain. Boc is therefore a silent HPE modifier gene in mice. Furthermore, Cdo and Boc have specific, selective roles in Shh signaling in mammals, because Cdo;Boc double-mutant mice do not display the most severe HPE phenotype seen in Shh-null mice, nor do they have major defects in digit patterning or development of vertebrae, which are also Shh-dependent processes. This is in contrast to reported observations in Drosophila, where genetic removal of the Cdo and Boc orthologs Ihog and Boi results in a complete loss of response to the hedgehog ligand. Therefore, there is evolutionary divergence between mammals and insects in the requirement of the hedgehog pathway for Cdo/Ihog family members, with mammalian development involving additional factors and/or distinct mechanisms at this level of pathway regulation.

  10. Mutant p53: multiple mechanisms define biologic activity in cancer

    Michael Paul Kim

    2015-11-01

    Full Text Available The functional importance of p53 as a tumor suppressor gene is evident through its pervasiveness in cancer biology. The p53 gene is the most commonly altered gene in human cancer; however, not all genetic alterations are biologically equivalent. The majority of p53 alterations involve missense mutations that result in the production of mutant p53 proteins. Such mutant p53 proteins lack normal p53 function and may acquire novel functions, often with deleterious effects. Here, we review characterized mechanisms of mutant p53 gain of function in multiple model systems. In addition, we review mutant p53 addiction as emerging evidence suggests that tumors may depend on sustained mutant p53 activity for continued growth. We also discuss the role of p53 in stromal elements and their contribution to tumor initiation and progression. Lastly, current genetic mouse models of mutant p53 are reviewed and their limitations discussed.

  11. Mutant p53 in cell adhesion and motility.

    Yeudall, W Andrew; Wrighton, Katharine H; Deb, Sumitra

    2013-01-01

    Pro-oncogenic properties of mutant p53 were investigated with the aid of migration assays, adhesion assays, and soft agar growth assays using cells stably expressing gain-of-function p53 mutants. To determine cell migration, "wound-healing" (scratch) assays and haptotactic (chamber) assays were used. H1299 cells expressing mutant p53 were found to migrate more rapidly than cells transfected with empty vector alone. Results from both types of migration assay were broadly similar. Migratory ability differed for different p53 mutants, suggesting allele-specific effects. Cells expressing p53 mutants also showed enhanced adhesion to extracellular matrix compare to controls. Furthermore, stable transfection of mutant p53-H179L into NIH3T3 fibroblasts was sufficient to allow anchorage-independent growth in soft agar. PMID:23150443

  12. Isolation and characterization of Klebsiella pneumoniae unencapsulated mutants

    Klebsiella pneumoniae mutants were obtained after UV irradiation and negative selection with anticapsular serum. Unencapsulation, rather than expression of a structurally altered capsule, was found in the mutants. The mutant strains showed no alterations in their outer membrane proteins and lipopolysaccharide, and a great similarity with the wild type in the properties tested (serum resistance, antimicrobial sensitivity, and lipopolysaccharide-specific bacteriophage sensitivity), with the exception of a higher cell surface hydrophobicity and resistance to bacteriophage FC3-9

  13. Induction of petite yeast mutants by membrane-active agents.

    Jiménez, J.; Longo, E.; Benítez, T

    1988-01-01

    Ethanol proved to be a strong mutagenic agent of Saccharomyces mitochondrial DNA. Other active membrane solvents, such as tert-butanol, isopropanol, and sodium dodecyl sulfate, also turned out to be powerful petite mutation [rho-] inducers. Mutants defective in ergosterol synthesis (erg mutants) showed an extremely high frequency of spontaneous petite cells, suggesting that mitochondrial membrane alterations that were caused either by changes in its composition, as in the erg mutants, or by t...

  14. Hydrocarbon assimilation and biosurfactant production in Pseudomonas aeruginosa mutants.

    Koch, A K; Käppeli, O; Fiechter, A; Reiser, J.

    1991-01-01

    We isolated transposon Tn5-GM-induced mutants of Pseudomonas aeruginosa PG201 that were unable to grow in minimal media containing hexadecane as a carbon source. Some of these mutants lacked extracellular rhamnolipids, as shown by measuring the surface and interfacial tensions of the cell culture supernatants. Furthermore, the concentrated culture media of the mutant strains were tested for the presence of rhamnolipids by thin-layer chromatography and for rhamnolipid activities, including hem...

  15. Some mutants in maize obtained by irradiation with thermal neutrons

    Irradiation was carried out at the Bucharest Institute of Atomic Physics and the National Laboratory Brookhaven, USA. A description is given of 22 genic mutants affecting leaf color, plant size, and branching capacity. Characteristics related to pollen fertility and the vegetative period were affected in all the mutants. Improvement of pollen fertility was attempted over four generations without success. The maize mutants obtained by irradiation may be considered as being without practical significance. (author). 7 figs., 1 tab. 11 ref

  16. Mutants of rabies viruses in skunks: immune response and pathogenicity.

    Tolson, N D; Charlton, K M; Stewart, R B; Casey, G A; Webster, W A; Mackenzie, K.; Campbell, J. B.; Lawson, K. F.

    1990-01-01

    In studies to develop an oral rabies vaccine for wildlife, the immune response to and pathogenicity of two types of mutants of rabies viruses were examined. Forty-five small plaque mutants were selected from cultures of ERA rabies virus treated with 8-azaguanine or 5-fluorouracil and tested for pathogenicity in mice. Two of these mutants AZA 1 and AZA 2 (low pathogenicity in mice) were given to skunks by oral (bait), intestinal (endoscope) and intramuscular routes. Additionally, challenge vir...

  17. Plasmodium yoelii: induction of attenuated mutants by irradiation

    Waki, S.; Yonome, I.; Suzuki, M.

    1986-12-01

    When erythrocytic forms of Plasmodium yoelii nigeriensis, which is invariably fatal in mice, were exposed to X rays, the dose to reduce surviving parasites to one millionth was 100 gray (10 Krad). A suspension of 5 X 10(6) per ml of parasitized erythrocyte was irradiated at 100 gray, and 0.2 ml aliquots were inoculated into 22 mice. Eleven mice showed patent parasitemia, and in these the growth curves were less steep than that found in nonirradiated parasites. The infections of 8 mice of the 11 were self-resolving, and the attenuated feature of the parasites maintained following a limited number of blood passages. The parasites were slowly growing even in nude mice and cause self-resolving infections in intact mice. BALB/c mice immunized with the attenuated parasites were protected against subsequent challenge infections with the original virulent erythrocytic and sporogonic forms. These findings indicate that attenuated mutants of malaria parasites can be readily induced by this method.

  18. Producing Conditional Mutants for Studying Plant Microtubule Function

    Richard Cyr

    2009-09-29

    The cytoskeleton, and in particular its microtubule component, participates in several processes that directly affect growth and development in higher plants. Normal cytoskeletal function requires the precise and orderly arrangement of microtubules into several cell cycle and developmentally specific arrays. One of these, the cortical array, is notable for its role in directing the deposition of cellulose (the most prominent polymer in the biosphere). An understanding of how these arrays form, and the molecular interactions that contribute to their function, is incomplete. To gain a better understanding of how microtubules work, we have been working to characterize mutants in critical cytoskeletal genes. This characterization is being carried out at the subcellular level using vital microtubule gene constructs. In the last year of funding colleagues have discovered that gamma-tubulin complexes form along the lengths of cortical microtubules where they act to spawn new microtubules at a characteristic 40 deg angle. This finding complements nicely the finding from our lab (which was funded by the DOE) showing that microtubule encounters are angle dependent; high angles encounters results in catastrophic collisions while low angle encounters result in favorable zippering. The finding of a 40 deg spawn of new microtubules from extant microtubule, together with aforementioned rules of encounters, insures favorable co-alignment in the array. I was invited to write a New and Views essay on this topic and a PDF is attached (News and Views policy does not permit funding acknowledgments and so I was not allowed to acknowledge support from the DOE).

  19. Google: a narrativa de uma marca mutante

    Elizete de Azevedo Kreutz

    2010-01-01

    Full Text Available As marcas mutantes já fazem parte de nossa realidade, embora ainda não totalmente percebidas e/ou aceitas como tal. O presente artigo busca refletir sobre a relevância dessas novas estratégias de comunicação e branding, identificando suas principais características. Para isso, utilizamos o método de estudo de caso, o Google, ancorado nos métodos de pesquisa bibliográfica e de internet. A escolha foi intencional, posto que a organização é referência em sua categoria, mecanismo de busca, e reflete essa estratégia comunicacional contemporânea. Como resultado, as informações obtidas nos possibilitam compreender essa tendência de comportamento de marca que busca a interação com seus públicos.

  20. Winter barley mutants created in the Ukraine

    Full text: Increasing fodder and protein production is one of the objectives of the development of agriculture in Ukraine. Higher productivity of fodder crops, due to new highly productive varieties, is the means to meet this aim. Winter barley is an important crop for fodder purposes. The climate of the Ukraine is favourable for growing this crop. The areas used for the growth of winter barley are however, small (500,000-550,000 ha) and there is a shortage of good quality varieties. The main aim of the work was therefore to create new varieties of highly productive winter barley, of good quality. The new varieties and mutation lines of winter barley were created under the influence of water solutions of N-nitroso-N-methylurea (NMH - 0,012, 0,005%), N-nitroso-N-ethylurea (NEH - 0,05; 0.025; 0,012%) ethyleneimine (EI - 0,02; 0,01; 0,005%) on winter barley seeds of the varieties of local and foreign selections. On the basis of many years of investigations (1984-94) the following mutations were described: hard-grained, winter-hardiness, earliness, middle-maturity, late-maturity, wide and large leaves, narrow leaves, multinodal, great number of leaves, great number of flowers, strong stem (lodging resistant), tallness, semi-dwarfness, dwarfness, and high productivity. Particularly valuable are mutants with high productivity of green bulk. Their potential yield is 70 t/ha. As a result of the work two varieties of winter barley 'Shyrokolysty' and 'Kormovy' were released into the State register of plant varieties of the Ukraine. The other valuable mutant genotypes are used in cross breeding programmes. (author)

  1. Yield and quality of induced mutants in sugarcane

    Twenty-one near-normal and 4 drastic mutants isolated from mutagen-treated (X-rays, gamma rays and chemical mutagens) sugarcane variety 'Co 419' were tested for yield and juice quality. Mutants '368. and '419/1' had higher yield of cane and higher commercial cane sugar than 'Co 419'. Several mutants, especially the drastic mutants, had higher percentage of sucrose than 'Co 419'. The types with higher percentage of sucrose occurred much more frequently than the higher-yielding ones, indicating more frequent occurrence of disturbances in growth, resulting in diversion of more sucrose to storage than to the apical meristem. (auth.)

  2. Analysis of canthaxanthin and related pigments from Gordonia jacobaea mutants.

    de Miguel, T; Sieiro, C; Poza, M; Villa, T G

    2001-03-01

    A collection of 43 mutant strains of the bacterium Gordonia jacobaea was obtained by means of ethyl methanesulfonate treatment, and the strains were selected for their different pigmentation with respect to the wild-type strain. None of the mutants showed auxotrophy. They all showed good genetic stability and a growth rate similar to that of the parental strain. Canthaxanthin and other carotenoids from these mutants were extracted with acetone and ethanol and separated by high-performance liquid chromatography (HPLC). These HPLC analyses, together with spectrophotometric detection at 480 nm, revealed variations in the pigment contents of the different mutant strains. PMID:11312835

  3. Wild-type but not mutant huntingtin modulates the transcriptional activity of liver X receptors

    Futter, Marie; Diekmann, Heike; Schoenmakers, Erik; Sadiq, Oana; Chatterjee, Krishna; Rubinsztein, David C

    2009-01-01

    Background: Huntington’s disease is caused by expansion of a polyglutamine tract found in the amino-terminal of the ubiquitously expressed protein huntingtin. Well studied in its mutant form, huntingtin has a wide variety of normal functions, loss of which may also contribute to disease progression. Widespread transcriptional dysfunction occurs in brains of Huntington’s disease patients and in transgenic mouse and cell models of Huntington’s disease. Methods: To identify new transcriptional p...

  4. Yellow mutant albinism: cytochemical, ultrastructural, and genetic characterization suggesting multiple allelism.

    Hu, F.; Hanifin, J. M.; Prescott, G H; Tongue, A C

    1980-01-01

    This report describes three sisters, including monozygotic (MZ) twins, with clinical, ultrastructural, and histochemical features typical of yellow mutant albinism; This form of albinism is clinically similar to the tyrosinase-positive type, but hair bulbs showed (1) organelles similar to red hair pheomelanosomes and (2) absence of tyrosinase activity. Classical tyrosinase-negative albinism was found in a maternal cousin of the probands. Pedigree analysis of this family suggests multiple alle...

  5. Correlation between in vitro cytotoxicity and in vivo lethal activity in mice of epsilon toxin mutants from Clostridium perfringens.

    Jonatan Dorca-Arévalo

    Full Text Available Epsilon toxin (Etx from Clostridium perfringens is a pore-forming protein with a lethal effect on livestock, producing severe enterotoxemia characterized by general edema and neurological alterations. Site-specific mutations of the toxin are valuable tools to study the cellular and molecular mechanism of the toxin activity. In particular, mutants with paired cysteine substitutions that affect the membrane insertion domain behaved as dominant-negative inhibitors of toxin activity in MDCK cells. We produced similar mutants, together with a well-known non-toxic mutant (Etx-H106P, as green fluorescent protein (GFP fusion proteins to perform in vivo studies in an acutely intoxicated mouse model. The mutant (GFP-Etx-I51C/A114C had a lethal effect with generalized edema, and accumulated in the brain parenchyma due to its ability to cross the blood-brain barrier (BBB. In the renal system, this mutant had a cytotoxic effect on distal tubule epithelial cells. The other mutants studied (GFP-Etx-V56C/F118C and GFP-Etx-H106P did not have a lethal effect or cross the BBB, and failed to induce a cytotoxic effect on renal epithelial cells. These data suggest a direct correlation between the lethal effect of the toxin, with its cytotoxic effect on the kidney distal tubule cells, and the ability to cross the BBB.

  6. Correlation between in vitro cytotoxicity and in vivo lethal activity in mice of epsilon toxin mutants from Clostridium perfringens.

    Dorca-Arévalo, Jonatan; Pauillac, Serge; Díaz-Hidalgo, Laura; Martín-Satué, Mireia; Popoff, Michel R; Blasi, Juan

    2014-01-01

    Epsilon toxin (Etx) from Clostridium perfringens is a pore-forming protein with a lethal effect on livestock, producing severe enterotoxemia characterized by general edema and neurological alterations. Site-specific mutations of the toxin are valuable tools to study the cellular and molecular mechanism of the toxin activity. In particular, mutants with paired cysteine substitutions that affect the membrane insertion domain behaved as dominant-negative inhibitors of toxin activity in MDCK cells. We produced similar mutants, together with a well-known non-toxic mutant (Etx-H106P), as green fluorescent protein (GFP) fusion proteins to perform in vivo studies in an acutely intoxicated mouse model. The mutant (GFP-Etx-I51C/A114C) had a lethal effect with generalized edema, and accumulated in the brain parenchyma due to its ability to cross the blood-brain barrier (BBB). In the renal system, this mutant had a cytotoxic effect on distal tubule epithelial cells. The other mutants studied (GFP-Etx-V56C/F118C and GFP-Etx-H106P) did not have a lethal effect or cross the BBB, and failed to induce a cytotoxic effect on renal epithelial cells. These data suggest a direct correlation between the lethal effect of the toxin, with its cytotoxic effect on the kidney distal tubule cells, and the ability to cross the BBB. PMID:25013927

  7. Co-occurence of filamentation defects and impaired biofilms in Candida albicans protein kinase mutants.

    Konstantinidou, Nina; Morrissey, John Patrick

    2015-12-01

    Pathogenicity of Candida albicans is linked with its developmental stages, notably the capacity switch from yeast-like to hyphal growth, and to form biofilms on surfaces. To better understand the cellular processes involved in C. albicans development, a collection of 63 C. albicans protein kinase mutants was screened for biofilm formation in a microtitre plate assay. Thirty-eight mutants displayed some degree of biofilm impairment, with 20 categorised as poor biofilm formers. All the poor biofilm formers were also defective in the switch from yeast to hyphae, establishing it as a primary defect. Five genes, VPS15, IME2, PKH3, PGA43 and CEX1, encode proteins not previously reported to influence hyphal development or biofilm formation. Network analysis established that individual components of some processes, most interestingly MAP kinase pathways, are not required for biofilm formation, most likely indicating functional redundancy. Mutants were also screened for their response to bacterial supernatants and it was found that Pseudomonas aeruginosa supernatants inhibited biofilm formation in all mutants, regardless of the presence of homoserine lactones (HSLs). In contrast, Candida morphology was only affected by supernatant containing HSLs. This confirms the distinct HSL-dependent inhibition of filamentation and the HSL-independent impairment of biofilm development by P. aeruginosa. PMID:26472756

  8. Identification of Vitis vinifera L. grape berry skin color mutants and polyphenolic profile.

    Ferreira, Vanessa; Fernandes, Fátima; Pinto-Carnide, Olinda; Valentão, Patrícia; Falco, Virgílio; Martín, Juan Pedro; Ortiz, Jesús María; Arroyo-García, Rosa; Andrade, Paula B; Castro, Isaura

    2016-03-01

    A germplasm set of twenty-five grapevine accessions, forming eleven groups of possible berry skin color mutants, were genotyped with twelve microsatellite loci, being eleven of them identified as true color mutants. The polyphenolic profiling of the confirmed mutant cultivars revealed a total of twenty-four polyphenols, comprising non-colored compounds (phenolic acids, flavan-3-ols, flavonols and a stilbene) and anthocyanins. Results showed differences in the contribution of malvidin-3-O-glucoside to the characteristic Pinot Noir anthocyanins profile. Regarding the two Pique-Poul colored variants, the lighter variant was richer than the darker one in all classes of compounds, excepting anthocyanins. In Moscatel Galego Roxo the F3'H pathway seems to be more active than F3'5'H, resulting in higher amounts of cyanidin, precursor of the cyanidin derivatives. As far as we are aware, this is the first time that a relationship between the content of polyphenolic compounds is established in groups of grape berry skin color mutant cultivars. PMID:26471534

  9. Characterization of a non-pigment producing Monascus purpureus mutant strain.

    Rasheva, Tanya V; Nedeva, Trayana S; Hallet, Jean-Noel; Kujumdzieva, Anna V

    2003-01-01

    A characterization of a non-pigment producing mutant Monascus purpureus M12 compared with its parental strain Monascus purpureus Went CBS 109.07 has been performed aiming to investigate the relation between pigment biosynthesis and other characteristics of these fungi. A comparison has been made of morphological features, some physiological properties and biochemical activities of both strains. The albino mutant exhibits an anamorph life cycle, high conidia forming capability, slower radial growth rate and temperature sensitivity. The assimilation capacity of both strains for mono-, disaccharides and some alcohols is in the same range (Yx/c 0.2 - 0.35), while the red strain has a higher fermentation capacity. In a selected albino mutant, the growth rate, metabolic activity and capacity for production of typical for Monascus fungi secondary metabolites were reduced considerably. Hydrolytic activity towards natural substrates expressed through glucoamylase and protease was approximately 10 fold lower in the non pigment producing strain (0.05 - 0.08 U/mg protein and 0.01 - 0.07 U/mg protein respectively) compared with the red one. Important qualitative differences between both strains was found in fatty acid composition and in the production of citrinin and monacolin. The mutant strain possessed C17, C20 and C22 fatty acids and did not produce citrinin. PMID:12777069

  10. Altered gene regulation and synaptic morphology in Drosophila learning and memory mutants.

    Guan, Zhuo; Buhl, Lauren K; Quinn, William G; Littleton, J Troy

    2011-01-01

    Genetic studies in Drosophila have revealed two separable long-term memory pathways defined as anesthesia-resistant memory (ARM) and long-lasting long-term memory (LLTM). ARM is disrupted in radish (rsh) mutants, whereas LLTM requires CREB-dependent protein synthesis. Although the downstream effectors of ARM and LLTM are distinct, pathways leading to these forms of memory may share the cAMP cascade critical for associative learning. Dunce, which encodes a cAMP-specific phosphodiesterase, and rutabaga, which encodes an adenylyl cyclase, both disrupt short-term memory. Amnesiac encodes a pituitary adenylyl cyclase-activating peptide homolog and is required for middle-term memory. Here, we demonstrate that the Radish protein localizes to the cytoplasm and nucleus and is a PKA phosphorylation target in vitro. To characterize how these plasticity pathways may manifest at the synaptic level, we assayed synaptic connectivity and performed an expression analysis to detect altered transcriptional networks in rutabaga, dunce, amnesiac, and radish mutants. All four mutants disrupt specific aspects of synaptic connectivity at larval neuromuscular junctions (NMJs). Genome-wide DNA microarray analysis revealed ∼375 transcripts that are altered in these mutants, suggesting defects in multiple neuronal signaling pathways. In particular, the transcriptional target Lapsyn, which encodes a leucine-rich repeat cell adhesion protein, localizes to synapses and regulates synaptic growth. This analysis provides insights into the Radish-dependent ARM pathway and novel transcriptional targets that may contribute to memory processing in Drosophila. PMID:21422168

  11. Normal DNA ligase activity in a γ-ray-sensitive Chinese hamster mutant

    A Chinese hamster cell mutant (XR-1) was previously described that is extremely deficient in the repair of double-strand DNA breaks produced by γ-irradiation during the sensitive G1-early-S period and somewhat deficient in repair of γ-ray-induced single-strand DNA breaks. To determine whether a deficiency in DNA ligase activity might underlie the biochemical defect, protein extracts from mutant and parental cells were examined for their ability to ligate single- and double-strand breaks in DNA. The kinetics of ligation of single 5'-phosphate-3'-hydroxyl breaks in double-stranded DNA were the same in protein extracts from both cells. After separation of protein extracts by gel-filtration chromatography, the percentage of activity in the large and small molecular forms of DNA ligase was also similar in the two cells. Finally, protein extracts prepared from exponentially growing or G1-synchronized mutant and parental cells were equal in their ability to ligate blunt-end DNA substrates. These data suggest that a deficiency in DNA ligase is not the cause of the repair defect in the XR-1 mutant cell. (Auth.)

  12. Use of an otolith-deficient mutant in studies of fish behavior in microgravity

    Ijiri, K.; Mizuno, R.; Eguchi, H.

    2003-10-01

    The mutant strain ( ha) of medaka ( Oryzias latipes) lack utricular otoliths as fry, and some never form otoliths for life. The cross (Fl generation) between the strain having good eyesight and another strain having ordinary eyesight augmented visual acuity of the Fl generation. Crossing the good eyesight strain and ha mutant produced fish having good eyesight and less sensitivity to gravity in the F2 population. Their tolerance to microgravity was tested by parabolic flight using an airplane. The fish exhibited less looping and no differences in degree of looping between light and dark conditions, suggesting that loss of eyesight (in darkness) is not a direct cause for looping behavior in microgravity. The ha embryos could not form utricular otoliths. They did form saccular otoliths, but with a delay. Fry of the mutant fish lacking the utricular otoliths are highly dependent on light upon hatching and exhibit a perfect dorsal-light response (DLR). As they grow, they eventually shift from being light-dependent to being gravity-dependent. Continuous treatment of the fry with altered light direction suppressed this shift to gravity dependence. Being less dependent on gravity, these fish can serve as models in studying the differences expected for the vestibular system of fish reared in microgravity. When these fish were exposed to microgravity (parabolic flights) of an airplane, they spent far less time looping than fish reared in an ordinary light regimen.

  13. Ascertainment of the effect of differential growth rates of mutants on observed mutant frequencies in X-irradiated mammalian cells

    As it is not known to what extent differential growth rates of induced mutants lead to over- and under-representation of mutants in treated populations and thereby affect the determination of mutant frequencies, the mutation induction in X-irradiated L5178Y mouse lymphoma cells was determined via two methods. The first method involves the standard protocol which may suffer from the effect of differential growth rates, while the second method is based upon the fluctuation test in which the differential growth rates can be actually measured. It appeared that the standard protocol led to a mutant frequency that was similar to the mutant frequency determined in the fluctuation test. Therefore, the standard protocol appears to lead to only a minor under-estimation if any. Substantial heterogeneity in growth rates of induced mutants was observed, but the mutants with a selective advantage appear largely to compensate for the mutants that are lost because of selective disadvantage. It was calculated that the chance for isolating the same mutant twice from a treated population had been increased 2.2-fold because of the observed differential growth rates. (orig./AJ)

  14. Suppression of Id2, a member of the inhibitor of differentiation family and a target of mutant p53, is required for mutant p53 gain of function

    Yan, Wensheng; Liu, Gang; Scoumanne, Ariane; Chen, Xinbin

    2008-01-01

    Over-expression of mutant p53 is a common theme in human tumors, suggesting a tumor-promoting gain of function for mutant p53. To elucidate whether and how mutant p53 acquires its gain of function, mutant p53 is inducibly knocked down in SW480 colon cancer cell line, which contains mutant p53(R273H/P309S), and MIA-PaCa-2 pancreatic cancer cell line, which contains mutant p53(R248W). We found that knockdown of mutant p53 markedly inhibits cell proliferation. In addition, knockdown of mutant p5...

  15. Stability and kinetic studies on recombinant pyroglutamyl peptidase I and two mutant forms

    Mtawae, Karima

    2005-01-01

    This thesis investigates the kinetic and stability characteristics of recombinant human brain pyroglutamyl peptidase PAPI, an omega exopeptidase which cleaves pyroglutamic acid from the N-terminus of peptides and proteins. Three classes of pyroglutamyl peptidase have been found in a variety of bacteria, plant, animal, and human tissues; the first class includes the bacterial and animal type 1, pyroglutamyl peptidase I. The genes encoding bacterial PAPI have been cloned and characterized previ...

  16. Hyper- and hyporesponsive mutant forms of the Saccharomyces cerevisiae Ssy1 amino acid sensor

    Poulsen, Peter; Gaber, Richard F.; Kielland-Brandt, Morten

    2008-01-01

    The Saccharomyces cerevisiae integral membrane protein Ssy1p functions with Ssy5p and Ptr3p to sense extracellular amino acids. Signal transduction leads to processing and nuclear localization of Stp1p and Stp2p, transcriptional activators of many amino acid transporter genes. Ssy1p is structurally...

  17. Bacterial elongation factors EF-Tu, their mutants, chimeric forms, and domains: isolation and purification

    Jonák, Jiří

    2007-01-01

    Roč. 849, 1-2 (2007), s. 141-153. ISSN 1570-0232 R&D Projects: GA AV ČR IAA5052206; GA AV ČR KJB500520503; GA MŠk 2B06065 Institutional research plan: CEZ:AV0Z50520514 Keywords : bacterial elongation factors EF-Tu, , G-domain * recombinant EF-Tus * preparation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.935, year: 2007

  18. Fusion genetic analysis of jasmonate-signalling mutants in Arabidopsis

    Jensen, Anders Bøgh; Raventos, D.; Mundy, John Williams

    2002-01-01

    as two recessive mutants, designated joe1 and 2, that overexpress the reporter. Genetic analysis indicated that reporter overexpression in the joe mutants requires COI. joe1 responded to MeJA with increased anthocyanin accumulation, while joe2 responded with decreased root growth inhibition. In...

  19. Assessment and utilization of spontaneous sport mutant of grape

    The spontaneous sport mutant of Fujiminori was discovered in grape garden of Xiaying county at Ningbo city in 1993. The biological, botanical characteristics and fruit quality trait (such as total soluble solid, titratable acid, total water soluble sugar, reducing sugar, free Vc, organic acid and aroma etc.) of the mutant were continuously investigated from 1994 to 1999. The results showed that the sport mutant grew more vigorously, having multiple-bearing capacity in the year cycle. Fruit quality determination demonstrated that total soluble sugar, reducing sugar, soluble solids content and aroma contents of the mutant were higher than those of maternal plant in different degree, while titratable acid content of mutant was deceased. Meanwhile, it was also found that the berries of mutant are firmer and have longer storage life. The RAPD analysis of the genomic DNAs extracted from the young leaves of the spontaneous sport mutant indicated that there were some differential bands in the PCR amplified products using the arbitrary primers, which indicated the genotype diversity happened in the spontaneous mutation of grape.The mutant had been successfully developed the new grape variety named as 'Yongyou No. 1' via selection breeding method. The variety was approved by Ningbo Science and Technology Bureau in 1999 and was rapidly planted at other regions, such as Fenghua County, Yuyao County, Cixi County, Ninghai County, Shaoxing City, Jiaxing City and Hangzhou City, etc. Due to its high quality and productivity, it exhibits the extensive application potential in the future. (author)

  20. Development of Database Software with Plant Mutant Resources

    In this research, mutants induced by nuclear radiation are developed information computerised system. The status and progress on the collection, identification and utilization of mutants in Korea are introduced. And it was produced home page, manual, test record, construction of system

  1. Tumor suppressor PTEN affects tau phosphorylation: deficiency in the phosphatase activity of PTEN increases aggregation of an FTDP-17 mutant Tau

    Zhang Xue

    2006-07-01

    Full Text Available Abstract Background Aberrant hyperphosphorylation of tau protein has been implicated in a variety of neurodegenerative disorders. Although a number of protein kinases have been shown to phosphorylate tau in vitro and in vivo, the molecular mechanisms by which tau phosphorylation is regulated pathophysiologically are largely unknown. Recently, a growing body of evidence suggests a link between tau phosphorylation and PI3K signaling. In this study, phosphorylation, aggregation and binding to the microtubule of a mutant frontal temporal dementia and parkinsonism linked to chromosome 17 (FTDP-17 tau in the presence of tumor suppressor PTEN, a major regulatory component in PI3K signaling, were investigated. Results Phosphorylation of the human mutant FTDP-17 tau, T40RW, was evaluated using different phospho-tau specific antibodies in the presence of human wild-type or phosphatase activity null mutant PTEN. Among the evaluated phosphorylation sites, the levels of Ser214 and Thr212 phospho-tau proteins were significantly decreased in the presence of wild-type PTEN, and significantly increased when the phosphatase activity null mutant PTEN was ectopically expressed. Fractionation of the mutant tau transfected cells revealed a significantly increased level of soluble tau in cytosol when wild-type PTEN was expressed, and an elevated level of SDS-soluble tau aggregates in the presence of the mutant PTEN. In addition, the filter/trap assays detected more SDS-insoluble mutant tau aggregates in the cells overexpressing the mutant PTEN compared to those in the cells overexpressing wild-type PTEN and control DNA. This notion was confirmed by the immunocytochemical experiment which demonstrated that the overexpression of the phosphatase activity null mutant PTEN caused the mutant tau to form aggregates in the COS-7 cells. Conclusion Tumor suppressor PTEN can alleviate the phosporylation of the mutant FTDP-17 tau at specific sites, and the phosphatase activity

  2. Characteristics of mutant lines of sweet potato flour

    Research on mutation induction of sweet potato Sari variety has been conducted. Flour mutant lines were obtained from selection of M1V5 tubers irradiated by gamma rays at the dose of 10 Gy. Flour was made by peeling of tubers, then dried, blended and sieved. The quality test of flour have been done by measuring degree of whiteness, proximate, amylose contents, water content, soluble water, swelling power, and flour characteristics. The result of this work showed that flour of C6.26.13 mutant line had higher protein content than the parent plant with concentration of 3.62 % and its amylose content was also higher than the other mutant lines. The soluble water value of mutant lines were significant different compared to the parent plant from 1.82 to 2.25 % and swelling power from 4.28 to 5.55 %. The flour granule of the mutant line was different compared to the parent plant. (author)

  3. Mildew resistant and less lodging wheat mutants induced in Iran

    ''Tabassi'' is a lodging and mildew susceptible cultivar. To induce mutations, seeds were gamma irradiated (50 to 150 Gy) in 1982 and selection for lodging resistance was carried out in M2. During field experiments with the mutant lines in 1985/86 there has been a heavy mildew epidemic under which mutant 63-5-I (derived from 50 Gy treatment) exhibited considerable resistance and as a consequence, higher yield. The control was 100% infected, the mutant only 40%. The mutant yielded 31% more grain, 7.5% less straw and 4.5% more protein than the control. Lodging of 63-5-I was only 60% in an experiment under rainfed conditions in the same season, resulting in a relative yield increase of about 11%. In 1986/87 there was no mildew epidemic and the mutant yielded the same as ''Tabassi''

  4. Induction and characterization of Arabidopsis mutants by Ion beam

    This study was conducted to search the proper conditions and times for irradiating proton beam to seeds generally used for induction of mutant. Arabidopsis as model plants has good characters that is a short generation time, producing a lot of seeds, sequenced genome, developed maker. This points were the best materials for plant breeding for this study. The data of inducing mutants of Arabidopsis is used to be applicate to crops have more longer generation that is the final goals of this study. The goals of this project were to inducing and characterizing arabidopsis mutants by the proton ion beam and γ-ray. As well as, the purpose of this study was securing more than 10 lines of arabidopsis mutants in this project and also to know the changed DNA structure of the mutants using the basic data for applying to the more study

  5. Three mimic mutants for reclining foliage in common bean

    Two new mutants for the reclining foliage (RF) character were induced by treating seed of dry bean (Phaseolus vulgaris L.) breeding lines B-351 and 182-1 with 20 krad of .gamma.-radiation. These two mutants were shown to be monogenic and recessive. Allelism tests between the common RF gene rf and the two new mimic mutants for RF indicated that each of the three mutants has an independent locus. The symbols rf2 and rf3 were given to the new mutants. F2 data from the allelism tests showed that the rf2 stock carries a recessive epistatic gene in that does not affect rf2 but suppresses expression of rf and rf3. The rf locus was shown to be independent of the Sur locus for RF in linkage group VII

  6. Preferência de Bemisia tabaci biótipo B em linhagens mutantes de algodoeiro Bemisia tabaci biotype B preference in mutant cotton lines

    Francisco das Chagas Vidal Neto

    2008-02-01

    Full Text Available Os efeitos de caracteres mutantes morfológicos do algodoeiro (Gossypium hirsutum L. r. latifolium Hutch.: folha okra, bráctea frego e planta vermelha, em relação à resistência à mosca-branca (Bemisia tabaci biótipo B Hemiptera: Aleyrodidae, foram avaliados em experimentos com ou sem chance de escolha. Os experimentos foram conduzidos em casa-de-vegetação, no delineamento de blocos ao acaso, em fatorial 23 + 1, com quatro repetições. O mutante com a característica planta vermelha foi menos atrativo e menos preferido para oviposição, em relação à planta verde, em ambos os ensaios, com ou sem escolha. Não houve preferência quanto à forma da folha e ao tipo de bráctea.The effects of cotton lines (Gossypium hirsutum L. r. latifolium Hutch. with mutants morphologic characteristics: okra leaf, frego bract and red plant in relation to host plant resistance to whitefly (Bemisia tabaci bioyipe B Hemiptera: Aleyrodidae, were evaluated in choice or no choice assays. The assays were carried out in the greenhouse conditions, according to a completely randomized block design, in a 23 + 1 in a factorial arrangement with four replications. The mutant with red plant characteristic was less attractive and less preferred for oviposition than the normal green plant does, in both, whit or without choice tests. It did not have preference in relation to the form of the leaf and bract type.

  7. Identification of symbiotically defective mutants of Lotus japonicus affected in infection thread growth

    Lombardo, Fabien; Heckmann, Anne Birgitte Lau; Miwa, Hiroki;

    2006-01-01

    During the symbiotic interaction between legumes and rhizobia, the host cell plasma membrane and associated plant cell wall invaginate to form a tunnel-like infection thread, a structure in which bacteria divide to reach the plant root cortex. We isolated four Lotus japonicus mutants that make...

  8. Life without complex I: proteome analyses of an Arabidopsis mutant lacking the mitochondrial NADH dehydrogenase complex.

    Fromm, Steffanie; Senkler, Jennifer; Eubel, Holger; Peterhänsel, Christoph; Braun, Hans-Peter

    2016-05-01

    The mitochondrial NADH dehydrogenase complex (complex I) is of particular importance for the respiratory chain in mitochondria. It is the major electron entry site for the mitochondrial electron transport chain (mETC) and therefore of great significance for mitochondrial ATP generation. We recently described an Arabidopsis thaliana double-mutant lacking the genes encoding the carbonic anhydrases CA1 and CA2, which both form part of a plant-specific 'carbonic anhydrase domain' of mitochondrial complex I. The mutant lacks complex I completely. Here we report extended analyses for systematically characterizing the proteome of the ca1ca2 mutant. Using various proteomic tools, we show that lack of complex I causes reorganization of the cellular respiration system. Reduced electron entry into the respiratory chain at the first segment of the mETC leads to induction of complexes II and IV as well as alternative oxidase. Increased electron entry at later segments of the mETC requires an increase in oxidation of organic substrates. This is reflected by higher abundance of proteins involved in glycolysis, the tricarboxylic acid cycle and branched-chain amino acid catabolism. Proteins involved in the light reaction of photosynthesis, the Calvin cycle, tetrapyrrole biosynthesis, and photorespiration are clearly reduced, contributing to the significant delay in growth and development of the double-mutant. Finally, enzymes involved in defense against reactive oxygen species and stress symptoms are much induced. These together with previously reported insights into the function of plant complex I, which were obtained by analysing other complex I mutants, are integrated in order to comprehensively describe 'life without complex I'. PMID:27122571

  9. Growth, seed development and genetic analysis in wild type and Def mutant of Pisum sativum L

    Ayeh Kwadwo

    2011-11-01

    Full Text Available Abstract Background The def mutant pea (Pisum sativum L showed non-abscission of seeds from the funicule. Here we present data on seed development and growth pattern and their relationship in predicting this particular trait in wild type and mutant lines as well as the inheritance pattern of the def allele in F2 and F3 populations. Findings Pod length and seed fresh weight increase with fruit maturity and this may affect the abscission event in pea seeds. However, the seed position in either the distal and proximal ends of the pod did not show any difference. The growth factors of seed fresh weight (FW, width of funicles (WFN, seed width (SW and seed height (SH were highly correlated and their relationships were determined in both wild type and def mutant peas. The coefficient of determination R2 values for the relationship between WFN and FW, SW and SH and their various interactions were higher for the def dwarf type. Stepwise multiple regression analysis showed that variation of WFN was associated with SH and SW. Pearson's chi square analysis revealed that the inheritance and segregation of the Def locus in 3:1 ratio was significant in two F2 populations. Structural analysis of the F3 population was used to confirm the inheritance status of the Def locus in F2 heterozygote plants. Conclusions This study investigated the inheritance of the presence or absence of the Def allele, controlling the presence of an abscission zone (AZ or an abscission-less zone (ALZ forming in wild type and mutant lines respectively. The single major gene (Def controlling this phenotype was monogenic and def mutants were characterized and controlled by the homozygous recessive def allele that showed no palisade layers in the hilum region of the seed coat.

  10. Lactose metabolism in Streptococcus lactis: studies with a mutant lacking glucokinase and mannose-phosphotransferase activities

    Thompson, J.; Chassy, B.M.; Egan, W.

    1985-04-01

    A mutant of Streptococcus lactis 133 has been isolated that lacks both glucokinase and phosphoenolpyruvate-dependent mannose- phosphotransferase (mannose-PTS) activities. The double mutant S. lactis 133 mannose-PTSd GK- is unable to utilize either exogenously supplied or intracellularly generated glucose for growth. Fluorographic analyses of metabolites formed during the metabolism of (/sup 14/C)lactose labeled specifically in the glucose or galactosyl moiety established that the cells were unable to phosphorylate intracellular glucose. However, cells of S. lactis 133 mannose-PTSd GK- readily metabolized intracellular glucose 6-phosphate, and the growth rates and cell yield of the mutant and parental strains on sucrose were the same. During growth on lactose, S. lactis 133 mannose-PTSd GK- fermented only the galactose moiety of the disaccharide, and 1 mol of glucose was generated per mol of lactose consumed. For an equivalent concentration of lactose, the cell yield of the mutant was 50% that of the wild type. The specific rate of lactose utilization by growing cells of S. lactis 133 mannose-PTSd GK- was ca. 50% greater than that of the wild type, but the cell doubling times were 70 and 47 min, respectively. High-resolution /sup 31/P nuclear magnetic resonance studies of lactose transport by starved cells of S. lactis 133 and S. lactis 133 mannose-PTSd GK- showed that the latter cells contained elevated lactose-PTS activity. Throughout exponential growth on lactose, the mutant maintained an intracellular steady-state glucose concentration of 100 mM.