scholarly journals Protein Particles in Chlamydomonas Flagella Undergo a Transport Cycle Consisting of Four Phases

2001 ◽  
Vol 153 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Carlo Iomini ◽  
Veronica Babaev-Khaimov ◽  
Massimo Sassaroli ◽  
Gianni Piperno
Keyword(s):  
Phase I ◽  
Intraflagellar Transport ◽  
Retrograde Transport ◽  
Cytoplasmic Dynein ◽  
Phase Iii ◽  
Cycle Phase ◽  
Flagellar Assembly ◽  
Protein Particles ◽  
Velocity Changes ◽  
Phase I And Ii

We used an improved procedure to analyze the intraflagellar transport (IFT) of protein particles in Chlamydomonas and found that the frequency of the particles, not only the velocity, changes at each end of the flagella. Thus, particles undergo structural remodeling at both flagellar locations. Therefore, we propose that the IFT consists of a cycle composed of at least four phases: phases II and IV, in which particles undergo anterograde and retrograde transport, respectively, and phases I and III, in which particles are remodeled/exchanged at the proximal and distal end of the flagellum, respectively. In support of our model, we also identified 13 distinct mutants of flagellar assembly (fla), each defective in one or two consecutive phases of the IFT cycle. The phase I-II mutant fla10-1 revealed that cytoplasmic dynein requires the function of kinesin II to participate in the cycle. Phase I and II mutants accumulate complex A, a particle component, near the basal bodies. In contrast, phase III and IV mutants accumulate complex B, a second particle component, in flagellar bulges. Thus, fla mutations affect the function of each complex at different phases of the cycle.

scholarly journals CHARACTERISTICS ANALYSIS OF DRAGON FRUIT EXTRACT SKIN BETACYANIN of Hylocereus polyrhizus AND Hylocereus undatus WITH TEST OF STABILITY ORGANOLEPTIC JELLY AS ATLAS MEDIA

2016 ◽  
Vol 2 (1) ◽  
Author(s):  
Tutut Puji Lestari
Keyword(s):  
High School ◽  
Phase I ◽  
Junior High School ◽  
Junior High ◽  
Phase Iii ◽  
Fruit Skin ◽  
Dragon Fruit ◽  
Hylocereus Undatus ◽  
Hylocereus Polyrhizus ◽  
Phase I And Ii

Dragon fruit Hylocereus polyrhizus  and Hylocereus undatus are familiy of cactus, grown in Malang. The high consumption of dragon fruit, have an impact on the fruit skin buildup that simply disposed of as trash. Dragon fruit skin is known to have a source of natural red dye, which is Betacyanin. The purpose of this study was to determine the characteristics of the dragon fruit peel extract Betacyanin Hylocereus polyrhizus and Hylocereus undatus as well as the stability of the organoleptic jelly, which will be developed into a learning materials atlas for class VIII Junior High School. The study was conducted in September-October 2015. The study was conducted in three stages. This type of research phase I and II is True Experimental, and phase III is development. The results of phase I shows that various concentrations of ethanol (70% and 90%) have an effect on the characteristics of the extract Betacyanin skin dragon fruit Hylocereus polyrhizus and Hylocereus undatus, but very significant effect on skin extract dragon fruit Hylocereus undatus the treatment of N2, EI at pH 4,5. Later in the phase II study results showed that different concentrations of extracts of the best Betacyanin significantly affect the organoleptic stability of jelly. The results of phase III is the development of phase I and II studies into Atlas media for 8th grade of  Junior High School.  

scholarly journals The DHC1b (DHC2) Isoform of Cytoplasmic Dynein Is Required for Flagellar Assembly

1999 ◽  
Vol 144 (3) ◽  
pp. 473-481 ◽  
Author(s):  
Gregory J. Pazour ◽  
Bethany L. Dickert ◽  
George B. Witman
Keyword(s):  
Molecular Motors ◽  
Cell Movement ◽  
Intraflagellar Transport ◽  
Cytoplasmic Dynein ◽  
Cdna Clones ◽  
Western Blots ◽  
Heavy Chains ◽  
Different Types ◽  
Flagellar Assembly ◽  
Soluble Fractions

Dyneins are microtubule-based molecular motors involved in many different types of cell movement. Most dynein heavy chains (DHCs) clearly group into cytoplasmic or axonemal isoforms. However, DHC1b has been enigmatic. To learn more about this isoform, we isolated Chlamydomonas cDNA clones encoding a portion of DHC1b, and used these clones to identify a Chlamydomonas cell line with a deletion mutation in DHC1b. The mutant grows normally and appears to have a normal Golgi apparatus, but has very short flagella. The deletion also results in a massive redistribution of raft subunits from a peri-basal body pool (Cole, D.G., D.R. Diener, A.L. Himelblau, P.L. Beech, J.C. Fuster, and J.L. Rosenbaum. 1998. J. Cell Biol. 141:993–1008) to the flagella. Rafts are particles that normally move up and down the flagella in a process known as intraflagellar transport (IFT) (Kozminski, K.G., K.A. Johnson, P. Forscher, and J.L. Rosenbaum. 1993. Proc. Natl. Acad. Sci. USA. 90:5519–5523), which is essential for assembly and maintenance of flagella. The redistribution of raft subunits apparently occurs due to a defect in the retrograde component of IFT, suggesting that DHC1b is the motor for retrograde IFT. Consistent with this, Western blots indicate that DHC1b is present in the flagellum, predominantly in the detergent- and ATP-soluble fractions. These results indicate that DHC1b is a cytoplasmic dynein essential for flagellar assembly, probably because it is the motor for retrograde IFT.

scholarly journals The role of retrograde intraflagellar transport in flagellar assembly, maintenance, and function

2012 ◽  
Vol 199 (1) ◽  
pp. 151-167 ◽  
Author(s):  
Benjamin D. Engel ◽  
Hiroaki Ishikawa ◽  
Kimberly A. Wemmer ◽  
Stefan Geimer ◽  
Ken-ichi Wakabayashi ◽  
...  
Keyword(s):  
Intraflagellar Transport ◽  
Retrograde Transport ◽  
Full Length ◽  
Temperature Sensitive ◽  
Nonpermissive Temperature ◽  
Flagellar Beat ◽  
Flagellar Assembly ◽  
Ph Shock ◽  
And Function

The maintenance of flagellar length is believed to require both anterograde and retrograde intraflagellar transport (IFT). However, it is difficult to uncouple the functions of retrograde transport from anterograde, as null mutants in dynein heavy chain 1b (DHC1b) have stumpy flagella, demonstrating solely that retrograde IFT is required for flagellar assembly. We isolated a Chlamydomonas reinhardtii mutant (dhc1b-3) with a temperature-sensitive defect in DHC1b, enabling inducible inhibition of retrograde IFT in full-length flagella. Although dhc1b-3 flagella at the nonpermissive temperature (34°C) showed a dramatic reduction of retrograde IFT, they remained nearly full-length for many hours. However, dhc1b-3 cells at 34°C had strong defects in flagellar assembly after cell division or pH shock. Furthermore, dhc1b-3 cells displayed altered phototaxis and flagellar beat. Thus, robust retrograde IFT is required for flagellar assembly and function but is dispensable for the maintenance of flagellar length. Proteomic analysis of dhc1b-3 flagella revealed distinct classes of proteins that change in abundance when retrograde IFT is inhibited.

scholarly journals Phase I and II Clinical Trial Comparing the LBSap, Leishmune®, and Leish-Tec® Vaccines against Canine Visceral Leishmaniasis

Vaccines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 690
Author(s):  
Rodrigo Dian de Oliveira Aguiar-Soares ◽  
Bruno Mendes Roatt ◽  
Fernando Augusto Siqueira Mathias ◽  
Levi Eduardo Soares Reis ◽  
Jamille Mirelle de Oliveira Cardoso ◽  
...  
Keyword(s):  
Clinical Trial ◽  
T Lymphocytes ◽  
Visceral Leishmaniasis ◽  
Phase I ◽  
Phase Iii ◽  
Canine Visceral Leishmaniasis ◽  
Cd8 T Lymphocytes ◽  
Ifn Γ ◽  
Phase I And Ii

In this study, we performed a phase I and II clinical trial in dogs to evaluate the toxicity and immunogenicity of LBSap-vaccine prototype, in comparison to Leishmune® and Leish-Tec® vaccines. Twenty-eight dogs were classified in four groups: (i) control group received 1 mL of sterile 0.9% saline solution; (ii) LBSap group received 600 μg of Leishmania braziliensis promastigotes protein and 1 mg of saponin adjuvant; (iii) Leishmune®; and (iv) Leish-Tec®. The safety and toxicity of the vaccines were measured before and after three immunizations by clinical, biochemical, and hematological parameters. The clinical examinations revealed that some dogs of LBSap and Leishmune® groups presented changes at the site of vaccination inoculum, such as nodules, mild edema, and local pain, which were transient and disappeared seventy-two hours after vaccination, but these results indicate that adverse changes caused by the immunizations are tolerable. The immunogenicity results demonstrate an increase of B lymphocytes CD21+ regarding the Leishmune® group and monocytes CD14+ concerning LBSap and Leishmune® groups. In the in vitro analyses, an increase in lymphoproliferative activity in LBSap and Leishmune® groups was observed, with an increase of antigen-specific CD4+ and CD8+ T lymphocytes in the LBSap group. A second approach of in vitro assays aimed at evaluating the percentage of antigen-specific CD4+ and CD8+ T lymphocytes producers of IFN-γ and IL-4, where an increase in both IFN-γ producing subpopulations in the LBSap group was observed, also showed an increase in IFN-γ producers in CD8+ lymphocytes in the Leish-Tec® group. Our data regarding immunogenicity indicate that the vaccination process, especially with the LBSap vaccine, generated a protective immune response compatible with L. infantum parasite control. Based on the foregoing, the LBSap vaccine would be suitable for further studies of phase III clinical trial in endemic areas with high prevalence and incidence of canine visceral leishmaniasis (VL) cases.

scholarly journals Experimental Study on the Effect of Heat-Retaining and Diversion Facilities on Thermal Discharge from a Power Plant

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2267
Author(s):  
Ruixia Hao ◽  
Liyuan Qiao ◽  
Lijuan Han ◽  
Chun Tian
Keyword(s):  
Power Plant ◽  
Phase I ◽  
Temperature Rise ◽  
Retaining Wall ◽  
Water Environment ◽  
Phase Iii ◽  
Thermal Discharge ◽  
Surrounding Water ◽  
The Impact ◽  
Phase I And Ii

In order to reduce the influence of thermal discharge from the power plant on the surrounding water environment and the operation efficiency of the power plant, a distorted physical model was presented and applied to Huadian Kemen Power Plant for studying heat transport and analyzing the effects of heat-retaining and diversion facilities near the intake/outlet on the thermal discharge for six scenarios. Field investigations were also used to validate the model. This study is unique as it is the first to elaborate on the impact of heat-retaining and diversion facilities on thermal discharge. The results indicate that the construction of heat-retaining and diversion facilities can decrease the excess temperature at intake to meet the intake requirement and improve the distribution of low temperature rise, but the area of high temperature rise has an increase. When the heat-retaining wall and diversion dike were constructed, the maximum intake temperature rise of Phase III decreased significantly by 1.0–1.3 °C with an average decrease of 0.2 °C, and the maximum value of Phase I and II was reduced by 0.3 °C with little mean change. A comparative experiment with different construction heights was also conducted. Result analysis shows that when the crest elevation was reduced from 3 to 2 m, the influence on the intake temperature rise of Phase I and II could be ignored, and the average temperature rise of Phase III only had an increase of 0.1 °C, suggesting that constructions with 2 m play an effective role in reducing heat return to the intake.

scholarly journals Intraflagellar transport (IFT) cargo

2004 ◽  
Vol 164 (2) ◽  
pp. 255-266 ◽  
Author(s):  
Hongmin Qin ◽  
Dennis R. Diener ◽  
Stefan Geimer ◽  
Douglas G. Cole ◽  
Joel L. Rosenbaum
Keyword(s):  
Cell Body ◽  
Soluble Fraction ◽  
Intraflagellar Transport ◽  
Radial Spokes ◽  
Flagellar Assembly ◽  
Protein Particles ◽  
Bidirectional Movement

Intraflagellar transport (IFT) is the bidirectional movement of multisubunit protein particles along axonemal microtubules and is required for assembly and maintenance of eukaryotic flagella and cilia. One posited role of IFT is to transport flagellar precursors to the flagellar tip for assembly. Here, we examine radial spokes, axonemal subunits consisting of 22 polypeptides, as potential cargo for IFT. Radial spokes were found to be partially assembled in the cell body, before being transported to the flagellar tip by anterograde IFT. Fully assembled radial spokes, detached from axonemal microtubules during flagellar breakdown or turnover, are removed from flagella by retrograde IFT. Interactions between IFT particles, motors, radial spokes, and other axonemal proteins were verified by coimmunoprecipitation of these proteins from the soluble fraction of Chlamydomonas flagella. These studies indicate that one of the main roles of IFT in flagellar assembly and maintenance is to transport axonemal proteins in and out of the flagellum.

scholarly journals Retrograde Intraflagellar Transport Mutants Identify Complex A Proteins With Multiple Genetic Interactions in Chlamydomonas reinhardtii

Genetics ◽  
2009 ◽  
Vol 183 (3) ◽  
pp. 885-896 ◽  
Author(s):  
Carlo Iomini ◽  
Linya Li ◽  
Jessica M. Esparza ◽  
Susan K. Dutcher
Keyword(s):  
Intraflagellar Transport ◽  
Gene Interaction ◽  
Retrograde Transport ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Transport Mutants ◽  
Flagellar Assembly ◽  
Biochemical Genetic ◽  
Different Levels ◽  
Assembly Defect

The intraflagellar transport machinery is required for the assembly of cilia. It has been investigated by biochemical, genetic, and computational methods that have identified at least 21 proteins that assemble into two subcomplexes. It has been hypothesized that complex A is required for retrograde transport. Temperature-sensitive mutations in FLA15 and FLA17 show defects in retrograde intraflagellar transport (IFT) in Chlamydomonas. We show that IFT144 and IFT139, two complex A proteins, are encoded by FLA15 and FLA17, respectively. The fla15 allele is a missense mutation in a conserved cysteine and the fla17 allele is an in-frame deletion of three exons. The flagellar assembly defect of each mutant is rescued by the respective transgenes. In fla15 and fla17 mutants, bulges form in the distal one-third of the flagella at the permissive temperature and this phenotype is also rescued by the transgenes. These bulges contain the complex B component IFT74/72, but not α-tubulin or p28, a component of an inner dynein arm, which suggests specificity with respect to the proteins that accumulate in these bulges. IFT144 and IFT139 are likely to interact with each other and other proteins on the basis of three distinct genetic tests: (1) Double mutants display synthetic flagellar assembly defects at the permissive temperature, (2) heterozygous diploid strains exhibit second-site noncomplemention, and (3) transgenes confer two-copy suppression. Since these tests show different levels of phenotypic sensitivity, we propose they illustrate different gradations of gene interaction between complex A proteins themselves and with a complex B protein (IFT172).

scholarly journals A Dynein Light Intermediate Chain, D1bLIC, Is Required for Retrograde Intraflagellar Transport

2004 ◽  
Vol 15 (10) ◽  
pp. 4382-4394 ◽  
Author(s):  
Yuqing Hou ◽  
Gregory J. Pazour ◽  
George B. Witman
Keyword(s):  
Intraflagellar Transport ◽  
Cytoplasmic Dynein ◽  
Wild Type ◽  
Phosphate Binding ◽  
Conserved Domain ◽  
Wild Type Phenotype ◽  
Flagellar Assembly ◽  
Bidirectional Movement ◽  
Mutant Cells ◽  
Intermediate Chain

Intraflagellar transport (IFT), the bidirectional movement of particles along flagella, is essential for flagellar assembly. The motor for retrograde IFT in Chlamydomonas is cytoplasmic dynein 1b, which contains the dynein heavy chain DHC1b and the light intermediate chain (LIC) D1bLIC. To investigate a possible role for the LIC in IFT, we identified a d1blic mutant. DHC1b is reduced in the mutant, indicating that D1bLIC is important for stabilizing dynein 1b. The mutant has variable length flagella that accumulate IFT-particle proteins, indicative of a defect in retrograde IFT. Interestingly, the remaining DHC1b is normally distributed in the mutant flagella, strongly suggesting that the defect is in binding of cargo to the retrograde motor rather than in motor activity per se. Cell growth and Golgi apparatus localization and morphology are normal in the mutant, indicating that D1bLIC is involved mainly in retrograde IFT. Like mammalian LICs, D1bLIC has a phosphate-binding domain (P-loop) at its N-terminus. To investigate the function of this conserved domain, d1blic mutant cells were transformed with constructs designed to express D1bLIC proteins with mutated P-loops. The constructs rescued the mutant cells to a wild-type phenotype, indicating that the function of D1bLIC in IFT is independent of its P-loop.

Importance of sodium for recovery of calcium control in reoxygenated cardiomyocytes

1994 ◽  
Vol 267 (2) ◽  
pp. H506-H513 ◽  
Author(s):  
B. Siegmund ◽  
Y. V. Ladilov ◽  
H. M. Piper
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Phase Iii ◽  
Fura 2 ◽  
Adult Rat ◽  
Na Pump ◽  
Initial Drop ◽  
Na Depletion ◽  
Phase I And Ii

The role of Na+ in the recovery from severe anoxic Ca2+ overload was investigated in isolated quiescent ventricular cardiomyocytes from adult rat. Changes of cytosolic Ca2+ and Na+ concentrations were followed by the fura 2 and Na(+)-binding benzofuran isophthalate techniques, respectively. When the fura 2 ratio (340/380 nm) reached saturation in anoxic cells, indicating a severe cytosolic Ca2+ overload, the cells were reoxygenated. This caused a rapid initial drop of cytosolic Ca2+ to a lower but still elevated level (phase I), followed by oscillatory Ca2+ transients at this level (phase II) and, within 10 min, the reestablishment of a stable cytosolic Ca2+ concentration at the normal resting level (phase III). As previously shown [B. Siegmund, R. Zude, and H. M. Piper. Am. J. Physiol. 263 (Heart Circ. Physiol. 32): H1262–H1269, 1992], Ca2+ shifts in phase I and II are mainly due to uptake and release of Ca2+ by the sarcoplasmic reticulum. Phase I was unchanged, and phase II was much prolonged (> 60 min) in cells reoxygenated under Na+ pump inhibition (0.2 mM ouabain) or Na+ depletion. Phase III could only be reestablished (< 10 min) when ouabain was eluted or external Na+ replenished, respectively. The results show that full recovery of cytosolic Ca2+ control (phase III) requires an active sarcolemmal Na+ pump and the availability of external Na+. This indicates that phase III is determined by the transsarcolemmal extrusion of Ca2+ by a tandem mechanism consisting of 1) the Na+ pump, generating an extracellular-to-intracellular Na+ gradient, and 2) the sarcolemmal Na+/Ca2+ exchange, driven by that gradient to extrude Ca2+.

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