Amino acid patterns at different stages in the life cycle of rhodomelaceous algae

1980 ◽  
Vol 19 (12) ◽  
pp. 2751-2754 ◽  
Author(s):  
Sebastiano Sciuto ◽  
Mario Piattelli ◽  
Rosa Chellemi ◽  
Mario Cormaci ◽  
Giovanni Furnari
Keyword(s):  
Life Cycle ◽  
Amino Acid

scholarly journals An Intracellular Ammonium Transporter Is Necessary for Replication, Differentiation, and Resistance to Starvation and Osmotic Stress in Trypanosoma cruzi

mSphere ◽  
2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Teresa Cruz-Bustos ◽  
Evgeniy Potapenko ◽  
Melissa Storey ◽  
Roberto Docampo
Keyword(s):  
Life Cycle ◽  
Amino Acid ◽  
Osmotic Stress ◽  
Trypanosoma Cruzi ◽  
Etiologic Agent ◽  
Ammonium Transporter ◽  
Amino Acid Consumption ◽  
Acid Consumption ◽  
Acidic Compartments ◽  
Production Of Ammonia

Trypanosoma cruzi is an important human and animal pathogen and the etiologic agent of Chagas disease. The parasite undergoes drastic changes in its metabolism during its life cycle. Amino acid consumption becomes important in the infective stages and leads to the production of ammonia (NH3), which needs to be detoxified. We report here the identification of an ammonium (NH4 +) transporter that localizes to acidic compartments and is important for replication, differentiation, and resistance to starvation and osmotic stress.

scholarly journals Characterization of Recombinant Flaviviridae Viruses Possessing a Small Reporter Tag

2017 ◽  
Vol 92 (2) ◽  
Author(s):  
Tomokazu Tamura ◽  
Takasuke Fukuhara ◽  
Takuro Uchida ◽  
Chikako Ono ◽  
Hiroyuki Mori ◽  
...  
Keyword(s):  
Life Cycle ◽  
Amino Acid ◽  
Viral Life Cycle ◽  
Luciferase Gene ◽  
Content Type ◽  
Recombinant Viruses ◽  
Nanoluc Luciferase ◽  
The Stability ◽  
Split Luciferase

ABSTRACTThe familyFlaviviridaeconsists of four genera,Flavivirus,Pestivirus,Pegivirus, andHepacivirus, and comprises important pathogens of human and animals. Although the construction of recombinant viruses carrying reporter genes encoding fluorescent and bioluminescent proteins has been reported, the stable insertion of foreign genes into viral genomes retaining infectivity remains difficult. Here, we applied the 11-amino-acid subunit derived from NanoLuc luciferase to the engineering of theFlaviviridaeviruses and then examined the biological characteristics of the viruses. We successfully generated recombinant viruses carrying the split-luciferase gene, including dengue virus, Japanese encephalitis virus, hepatitis C virus (HCV), and bovine viral diarrhea virus. The stability of the viruses was confirmed by five rounds of serial passages in the respective susceptible cell lines. The propagation of the recombinant luciferase viruses in each cell line was comparable to that of the parental viruses. By using a purified counterpart luciferase protein, this split-luciferase assay can be applicable in various cell lines, even when it is difficult to transduce the counterpart gene. The efficacy of antiviral reagents against the recombinant viruses could be monitored by the reduction of luciferase expression, which was correlated with that of viral RNA, and the recombinant HCV was also useful to examine viral dynamicsin vivo. Taken together, our findings indicate that the recombinantFlaviviridaeviruses possessing the split NanoLuc luciferase gene generated here provide powerful tools to understand viral life cycle and pathogenesis and a robust platform to develop novel antivirals againstFlaviviridaeviruses.IMPORTANCEThe construction of reporter viruses possessing a stable transgene capable of expressing specific signals is crucial to investigations of viral life cycle and pathogenesis and the development of antivirals. However, it is difficult to maintain the stability of a large foreign gene, such as those for fluorescence and bioluminescence, after insertion into a viral genome. Here, we successfully generated recombinantFlaviviridaeviruses carrying the 11-amino-acid subunit derived from NanoLuc luciferase and demonstrated that these viruses are applicable toin vitroandin vivoexperiments, suggesting that these recombinantFlaviviridaeviruses are powerful tools for increasing our understanding of viral life cycle and pathogenesis and that these recombinant viruses will provide a robust platform to develop antivirals againstFlaviviridaeviruses.

TATA-binding protein and nuclear differentiation in Tetrahymena thermophila

1994 ◽  
Vol 14 (1) ◽  
pp. 723-734
Author(s):  
L A Stargell ◽  
M A Gorovsky
Keyword(s):  
Life Cycle ◽  
Amino Acid ◽  
Rna Polymerase Ii ◽  
Tetrahymena Thermophila ◽  
Polyclonal Antibodies ◽  
Binding Protein ◽  
Tata Binding Protein ◽  
Gene Encoding ◽  
Nuclear Differentiation

Unambiguous TATA boxes have not been identified in upstream sequences of Tetrahymena thermophila genes analyzed to date. To begin a characterization of the promoter requirements for RNA polymerase II, the gene encoding TATA-binding protein (TBP) was cloned from this species. The derived amino acid sequence for the conserved C-terminal domain of Tetrahymena TBP is one of the most divergent described and includes a unique 20-amino-acid C-terminal extension. Polyclonal antibodies generated against a fragment of Tetrahymena TBP recognize a 36-kDa protein in macronuclear preparations and also cross-react with yeast and human TBPs. Immunocytochemistry was used to examine the nuclear localization of TBP during growth, starvation, and conjugation (the sexual phase of the life cycle). The transcriptionally active macronuclei stained at all stages of the life cycle. The transcriptionally inert micronuclei did not stain during growth or starvation but surprisingly stained with anti-TBP throughout early stages of conjugation. Anti-TBP staining disappeared from developing micronuclei late in conjugation, corresponding to the onset of transcription in developing macronuclei. Since micronuclei do not enlarge or divide at this time, loss of TBP appears to be an active process. Thus, the transcriptional differences between macro- and micronuclei that arise during conjugation are associated with the loss of a major component of the basal transcription apparatus from developing micronuclei rather than its appearance in developing macronuclei.

scholarly journals TATA-binding protein and nuclear differentiation in Tetrahymena thermophila.

1994 ◽  
Vol 14 (1) ◽  
pp. 723-734 ◽  
Author(s):  
L A Stargell ◽  
M A Gorovsky
Keyword(s):  
Life Cycle ◽  
Amino Acid ◽  
Rna Polymerase Ii ◽  
Tetrahymena Thermophila ◽  
Polyclonal Antibodies ◽  
Binding Protein ◽  
Tata Binding Protein ◽  
Gene Encoding ◽  
Nuclear Differentiation

Unambiguous TATA boxes have not been identified in upstream sequences of Tetrahymena thermophila genes analyzed to date. To begin a characterization of the promoter requirements for RNA polymerase II, the gene encoding TATA-binding protein (TBP) was cloned from this species. The derived amino acid sequence for the conserved C-terminal domain of Tetrahymena TBP is one of the most divergent described and includes a unique 20-amino-acid C-terminal extension. Polyclonal antibodies generated against a fragment of Tetrahymena TBP recognize a 36-kDa protein in macronuclear preparations and also cross-react with yeast and human TBPs. Immunocytochemistry was used to examine the nuclear localization of TBP during growth, starvation, and conjugation (the sexual phase of the life cycle). The transcriptionally active macronuclei stained at all stages of the life cycle. The transcriptionally inert micronuclei did not stain during growth or starvation but surprisingly stained with anti-TBP throughout early stages of conjugation. Anti-TBP staining disappeared from developing micronuclei late in conjugation, corresponding to the onset of transcription in developing macronuclei. Since micronuclei do not enlarge or divide at this time, loss of TBP appears to be an active process. Thus, the transcriptional differences between macro- and micronuclei that arise during conjugation are associated with the loss of a major component of the basal transcription apparatus from developing micronuclei rather than its appearance in developing macronuclei.

The role of membrane transporters in Leishmania virulence

2017 ◽  
Vol 1 (6) ◽  
pp. 601-611 ◽  
Author(s):  
Snezhana Akpunarlieva ◽  
Richard Burchmore
Keyword(s):  
Life Cycle ◽  
Amino Acid ◽  
Membrane Transporters ◽  
Mammalian Host ◽  
Insect Vector ◽  
Parasite Life Cycle ◽  
Severe Morbidity ◽  
Intracellular Amastigotes ◽  
Genomic Analyses

Leishmania are parasitic protozoa which infect humans and cause severe morbidity and mortality. Leishmania parasitise as extracellular promastigotes in the insect vector and as intracellular amastigotes in the mammalian host. Cycling between hosts involves implementation of stringent and co-ordinated responses to shifting environmental conditions. One of the key dynamic aspects of Leishmania biology is substrate acquisition and metabolism. Genomic analyses have revealed that Leishmania encode many putative membrane transporters, many of which are differentially expressed during the parasite life cycle. Only a small fraction of these transporters, however, have been functionally characterised. Currently, most information is available about nutrient transporters, mainly involved in carbohydrate, amino acid, nucleobase and nucleoside, cofactor, and ion acquisition. Several have apparent roles in Leishmania virulence and will be discussed in this perspective.

scholarly journals Identification by Random Mutagenesis of Functional Domains in KREPB5 That Differentially Affect RNA Editing between Life Cycle Stages of Trypanosoma brucei

2015 ◽  
Vol 35 (23) ◽  
pp. 3945-3961 ◽  
Author(s):  
Suzanne M. McDermott ◽  
Jason Carnes ◽  
Kenneth Stuart
Keyword(s):  
Life Cycle ◽  
Amino Acid ◽  
Trypanosoma Brucei ◽  
Rna Editing ◽  
Bloodstream Form ◽  
Single Amino Acid ◽  
Wild Type ◽  
Rnase Iii ◽  
Content Type ◽  
Life Cycle Stages

KREPB5 is an essential component of ∼20S editosomes inTrypanosoma bruceiwhich contains a degenerate, noncatalytic RNase III domain. To explore the function of this protein, we used a novel approach to make and screen numerous conditional nullT. bruceibloodstream form cell lines that express randomly mutagenized KREPB5 alleles. We identified nine single amino acid substitutions that could not complement the conditional loss of wild-type KREPB5. Seven of these were within the RNase III domain, and two were in the C-terminal region that has no homology to known motifs. Exclusive expression of these mutated KREPB5 alleles in the absence of wild-type allele expression resulted in growth inhibition, the loss of ∼20S editosomes, and inhibition of RNA editing in BF cells. Eight of these mutations were lethal in bloodstream form parasites but not in procyclic-form parasites, showing that multiple domains function in a life cycle-dependent manner. Amino acid changes at a substantial number of positions, including up to 7 per allele, allowed complementation and thus did not block KREPB5 function. Hence, the degenerate RNase III domain and a newly identified domain are critical for KREPB5 function and have differential effects between the life cycle stages ofT. bruceithat differentially edit mRNAs.

scholarly journals Convergent recruitment of TALE homeodomain life cycle regulators to direct sporophyte development in land plants and brown algae

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Alok Arun ◽  
Susana M Coelho ◽  
Akira F Peters ◽  
Simon Bourdareau ◽  
Laurent Pérès ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Life Cycle ◽  
Amino Acid ◽  
Brown Algae ◽  
Land Plants ◽  
Developmental Program ◽  
Tale Homeodomain ◽  
Cycle Regulation ◽  
Sporophyte Development ◽  
Green Lineage

Three amino acid loop extension homeodomain transcription factors (TALE HD TFs) act as life cycle regulators in green algae and land plants. In mosses these regulators are required for the deployment of the sporophyte developmental program. We demonstrate that mutations in either of two TALE HD TF genes, OUROBOROS or SAMSARA, in the brown alga Ectocarpus result in conversion of the sporophyte generation into a gametophyte. The OUROBOROS and SAMSARA proteins heterodimerise in a similar manner to TALE HD TF life cycle regulators in the green lineage. These observations demonstrate that TALE-HD-TF-based life cycle regulation systems have an extremely ancient origin, and that these systems have been independently recruited to regulate sporophyte developmental programs in at least two different complex multicellular eukaryotic supergroups, Archaeplastida and Chromalveolata.

scholarly journals Convergent recruitment of life cycle regulators to direct sporophyte development in two eukaryotic supergroups

2018 ◽  
Author(s):  
Alok Arun ◽  
Susana M. Coelho ◽  
Akira F. Peters ◽  
Simon Bourdareau ◽  
Laurent Peres ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Life Cycle ◽  
Amino Acid ◽  
Green Algae ◽  
Brown Alga ◽  
Land Plants ◽  
Developmental Program ◽  
Cycle Regulation ◽  
Sporophyte Development ◽  
Green Lineage

AbstractThree amino acid loop extension homeodomain transcription factors (TALE HD TFs) act as life cycle regulators in green algae and land plants. In mosses these regulators are required for the deployment of the sporophyte developmental program. We demonstrate that mutations in either of two TALE HD TF genes, OUROBOROS or SAMSARA, in the brown alga Ectocarpus result in conversion of the sporophyte generation into a gametophyte. The OUROBOROS and SAMSARA proteins heterodimerise in a similar manner to TALE HD TF life cycle regulators in the green lineage. These observations demonstrate that TALE-HD-TF-based life cycle regulation systems have an extremely ancient origin, and that these systems have been independently recruited to regulate sporophyte developmental programs in at least two different complex multicellular eukaryotic supergroups, Archaeplastida and Chromalveolata.

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