Patterns of assimilate distribution in soybeans at maturity. II.* The time course of changes in 14C distribution in pods and stem sections

1977 ◽  
Vol 28 (3) ◽  
pp. 395 ◽  
Author(s):  
RA Stephenson ◽  
GL Wilson
Keyword(s):  
Time Course ◽  
Stages Of Development ◽  
Pod Development

Leaves at two levels in the canopy of determinate soybeans were allowed to assimilate 14CO2 at one of several stages of development from late pre-flowering until pod maturity, and the distribution of 14CO activity in above-ground parts of the plants was followed up to maturity. Between pre-flowering and early pod development, assimilate was stored in stems and transferred to pods during later development; at later stages, current assimilate went directly from leaves to pods. Carbon fixed subsequent to flowering went to pods in the axils of treated leaves, and to pods at the second nodes above and below fed leaves but not to adjacent nodes. The source of substrate for filling pods in the apical raceme was not apparent from this study. __________________ *Part I, Aust. J. Aguic. Res., 28: 203 (1977).

scholarly journals Transcriptional control of gene expression during development of Dictyostelium discoideum.

1982 ◽  
Vol 2 (11) ◽  
pp. 1417-1426 ◽  
Author(s):  
S M Landfear ◽  
P Lefebvre ◽  
S Chung ◽  
H F Lodish
Keyword(s):  
Dictyostelium Discoideum ◽  
Transcriptional Control ◽  
Time Course ◽  
In Vitro Transcription ◽  
Cell Contact ◽  
Cellular Slime Mold ◽  
Stages Of Development ◽  
Control Of Gene Expression ◽  
The Stability

During development of the cellular slime mold Dictyostelium discoideum, approximately 2,000 to 3,000 regulated mRNAs are induced when amoebae enter multicellular aggregates. We used in vitro transcription in isolated nuclei to follow the synthesis of individual mRNA precursors during development; these were quantitated by hybridization to cloned cDNAs or genomic DNAs. Those RNAs that are present at all stages of development--the common RNAs--were transcribed by nuclei from cells at all stages of development. By contrast, those RNAs that are present only after cells begin to aggregate--here called aggregation stage RNAs--were transcribed only by nuclei from cells at the aggregation and postaggregation stages of development. The temporal pattern of in vitro transcription correlated well with the time course of accumulation of different aggregation stage mRNAs. Continued expression of aggregation stage genes normally depends upon cell-to-cell contact or cyclic AMP (cAMP); when cells are disaggregated, the regulated mRNAs are rapidly and specifically degraded. When cAMP is subsequently added to the disaggregated cells, most of the mRNAs reaccumulate. We show here that disaggregation reduced 2- to 10-fold the relative transcription of several aggregation stage RNAs, whereas addition of cAMP to disaggregated cells reinduced the level of regulated gene transcription to values approximating those found in normal postaggregation cells. These results indicate that a representative set of Dictyostelium aggregation stage genes are under transcriptional control; both the transcription and the stability of these mRNAs require either continued cell-to-cell interactions or cAMP.

Effects of Various Timings of 2,4-DB on Runner-Type Peanut Development and Yield

1997 ◽  
Vol 24 (2) ◽  
pp. 105-106 ◽  
Author(s):  
W. J. Grichar ◽  
D. C. Sestak ◽  
B. A. Besler
Keyword(s):  
Field Experiments ◽  
Growing Season ◽  
Stages Of Development ◽  
Application Timing ◽  
Pod Yield ◽  
Pod Development ◽  
Growth Development

Abstract Field experiments were conducted to determine the effect of the dimethylamine salt of 2,4-DB at 0.45 kg ae/ha applied at various times during the growing season on runner peanut growth, development, and pod yield. The herbicide was applied once at 30, 45, 60, 90, or 120 d after planting. Additional treatments included 2,4-DB at 0.45 kg/ha applied twice beginning at 30, 60, or 90 d after planting or applied three times beginning at 30, 45, or 60 d after planting. The dates of application were selected to expose plants to the herbicide during all stages of development from prebloom through early pod development. Peanut yield and grade were not affected by 2,4-DB regardless of application timing or numbers of applications.

Relationship between the Stages of Development of Fusarium moniliforme ATCC 38932 and Production of Fusarin C

1997 ◽  
Vol 60 (4) ◽  
pp. 433-435
Author(s):  
MARIA J. CANTALEJO ◽  
JOSE M. CARRASCO ◽  
E. HERNÁNDEZ
Keyword(s):  
Fusarium Moniliforme ◽  
Time Course ◽  
Culture Medium ◽  
Developmental Stages ◽  
Sharp Decrease ◽  
Stages Of Development ◽  
Maximum Production ◽  
Time Course Study ◽  
Kinetics Of

A study of the kinetics of fusarin C production by Fusarium moniliforme ATCC 38932, a known producer of fusarin C, was carried out. This strain was subcultured on an EG medium for an adequate sporulation, and a 4% inoculum was transferred to the 10% ICI N medium. The conditions for the production of fusarin C in this synthetic culture medium were optimized. The time-course study of fusarin C performed over 26 days with this strain showed three different developmental stages in which a maximum production of fusarin C was reached on the 8th day of incubation; thereafter this strain ceased growing exponentially and exhibited a sharp decrease of fusarin C from that moment on.

Transcriptional control of gene expression during development of Dictyostelium discoideum

1982 ◽  
Vol 2 (11) ◽  
pp. 1417-1426
Author(s):  
S M Landfear ◽  
P Lefebvre ◽  
S Chung ◽  
H F Lodish
Keyword(s):  
Dictyostelium Discoideum ◽  
Transcriptional Control ◽  
Time Course ◽  
In Vitro Transcription ◽  
Cell Contact ◽  
Cellular Slime Mold ◽  
Stages Of Development ◽  
Control Of Gene Expression ◽  
The Stability

During development of the cellular slime mold Dictyostelium discoideum, approximately 2,000 to 3,000 regulated mRNAs are induced when amoebae enter multicellular aggregates. We used in vitro transcription in isolated nuclei to follow the synthesis of individual mRNA precursors during development; these were quantitated by hybridization to cloned cDNAs or genomic DNAs. Those RNAs that are present at all stages of development--the common RNAs--were transcribed by nuclei from cells at all stages of development. By contrast, those RNAs that are present only after cells begin to aggregate--here called aggregation stage RNAs--were transcribed only by nuclei from cells at the aggregation and postaggregation stages of development. The temporal pattern of in vitro transcription correlated well with the time course of accumulation of different aggregation stage mRNAs. Continued expression of aggregation stage genes normally depends upon cell-to-cell contact or cyclic AMP (cAMP); when cells are disaggregated, the regulated mRNAs are rapidly and specifically degraded. When cAMP is subsequently added to the disaggregated cells, most of the mRNAs reaccumulate. We show here that disaggregation reduced 2- to 10-fold the relative transcription of several aggregation stage RNAs, whereas addition of cAMP to disaggregated cells reinduced the level of regulated gene transcription to values approximating those found in normal postaggregation cells. These results indicate that a representative set of Dictyostelium aggregation stage genes are under transcriptional control; both the transcription and the stability of these mRNAs require either continued cell-to-cell interactions or cAMP.

Different Patterns of α-Tubulin Post-Translational Modification in Ovarian Nutritive Tubes of Two Hemipteran Insects

1991 ◽  
Vol 100 (3) ◽  
pp. 501-507 ◽  
Author(s):  
ALISTAIR HARRISON ◽  
HOWARD STEBBINGS ◽  
JEREMY S. HYAMS
Keyword(s):  
Time Course ◽  
Immunofluorescence Microscopy ◽  
The Body ◽  
Oncopeltus Fasciatus ◽  
Frozen Sections ◽  
Post Translational Modification ◽  
Stages Of Development ◽  
Weak Reaction ◽  
Specific Antibodies ◽  
The Difference

Usage of the tyrosinated, detyrosinated and acetylated forms of α-tubulin in ovarian nutritive tube microtubules of the hemipterans Oncopeltus fasciatus and Notonecta glauca glauca was investigated by immunofluorescence microscopy of frozen sections of ovarioles with isotype-specific antibodies. In Oncopeltus, nutritive tubes at all stages of development contained tyrosinated α-tubulin and showed only a weak reaction to antibodies to the detyrosinated and acetylated forms. In Notonecta, tyrosinated α-tubulin was confined to a zone around the periphery of functional nutritive tubes; the body of these tubes, and the older, redundant, nutritive tubes stained strongly for both the detyrosinated and acetylated isotypes. The difference in isotype usage between the two species was confirmed by immunoblotting of 2-D gels of ovariole extracts. The results are consistent with the different time-course of oogenesis, and hence the longevity of the nutritive tube microtubules, in the two insects. A model for the insertion of new microtubules into nutritive tubes as they grow is proposed.

Ultrastructural Changes of the Symbiotic Chlorella-Like Alga Isolated from Hydra Viridis

1982 ◽  
Vol 40 ◽  
pp. 320-321
Author(s):  
K.W. Lee ◽  
R.H. Meints ◽  
D. Kuczmarski ◽  
J.L. Van Etten
Keyword(s):  
Time Course ◽  
Reciprocal Cross ◽  
Ultrastructural Level ◽  
Ultrastructural Changes ◽  
Symbiotic Relationship ◽  
Cell Recognition ◽  
Green Hydra ◽  
Different Strains ◽  
Hydra Viridis

The physiological, biochemical, and ultrastructural aspects of the symbiotic relationship between the Chlorella-like algae and the hydra have been intensively investigated. Reciprocal cross-transfer of the Chlorellalike algae between different strains of green hydra provide a system for the study of cell recognition. However, our attempts to culture the algae free of the host hydra of the Florida strain, Hydra viridis, have been consistently unsuccessful. We were, therefore, prompted to examine the isolated algae at the ultrastructural level on a time course.

Destruction of Actin Filaments by Osmium Tetroxide

1977 ◽  
Vol 35 ◽  
pp. 466-467
Author(s):  
P. Maupin-Szamier ◽  
T. D. Pollard
Keyword(s):  
Actin Filaments ◽  
Time Course ◽  
Osmium Tetroxide ◽  
Rabbit Muscle ◽  
Muscle Actin ◽  
Sodium Phosphate Buffer ◽  
Transmission Electron ◽  
The Difference ◽  
Rates Of Decay ◽  
Short Time

We have studied the destruction of rabbit muscle actin filaments by osmium tetroxide (OSO4) to develop methods which will preserve the structure of actin filaments during preparation for transmission electron microscopy.Negatively stained F-actin, which appears as smooth, gently curved filaments in control samples (Fig. 1a), acquire an angular, distorted profile and break into progressively shorter pieces after exposure to OSO4 (Fig. 1b,c). We followed the time course of the reaction with viscometry since it is a simple, quantitative method to assess filament integrity. The difference in rates of decay in viscosity of polymerized actin solutions after the addition of four concentrations of OSO4 is illustrated in Fig. 2. Viscometry indicated that the rate of actin filament destruction is also dependent upon temperature, buffer type, buffer concentration, and pH, and requires the continued presence of OSO4. The conditions most favorable to filament preservation are fixation in a low concentration of OSO4 for a short time at 0°C in 100mM sodium phosphate buffer, pH 6.0.

The time course of calcium deposition in shells of the barnacle (Balanus amphititre amphititre) during cyprid-juvenile metamorphosis

1994 ◽  
Vol 52 ◽  
pp. 178-179
Author(s):  
Nancy R. Wallace ◽  
Craig C. Freudenrich ◽  
Karl Wilbur ◽  
Peter Ingram ◽  
Ann LeFurgey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Time Course ◽  
Vertical Plane ◽  
Mantle Cavity ◽  
Qualitative Assessment ◽  
Calcium Deposition ◽  
Free Swimming ◽  
Freeze Dried ◽  
Scanning Electron

The morphology of balanomorph barnacles during metamorphosis from the cyprid larval stage to the juvenile has been examined by light microscopy and scanning electron microscopy (SEM). The free-swimming cyprid attaches to a substrate, rotates 90° in the vertical plane, molts, and assumes the adult shape. The resulting metamorph is clad in soft cuticle and has an adult-like appearance with a mantle cavity, thorax with cirri, and incipient shell plates. At some time during the development from cyprid to juvenile, the barnacle begins to mineralize its shell, but it is not known whether calcification occurs before, during, or after ecdysis. To examine this issue, electron probe x-ray microanalysis (EPXMA) was used to detect calcium in cyprids and juveniles at various times during metamorphosis.Laboratory-raised, free-swimming cyprid larvae were allowed to settle on plastic coverslips in culture dishes of seawater. The cyprids were observed with a dissecting microscope, cryopreserved in liquid nitrogen-cooled liquid propane at various times (0-24 h) during metamorphosis, freeze dried, rotary carbon-coated, and examined with scanning electron microscopy (SEM). EPXMA dot maps were obtained in parallel for qualitative assessment of calcium and other elements in the carapace, wall, and opercular plates.

Arabidopsis 4-COUMAROYL-COA LIGASE 8 contributes to the biosynthesis of the benzenoid ring of coenzyme Q in peroxisomes

2019 ◽  
Vol 476 (22) ◽  
pp. 3521-3532
Author(s):  
Eric Soubeyrand ◽  
Megan Kelly ◽  
Shea A. Keene ◽  
Ann C. Bernert ◽  
Scott Latimer ◽  
...  
Keyword(s):  
Oxidative Metabolism ◽  
Time Course ◽  
Reverse Genetics ◽  
De Novo ◽  
Coenzyme Q ◽  
Control Level ◽  
Wild Type ◽  
Fluorescent Reporters ◽  
Coa Ligase ◽  
Peroxisomal Targeting

Plants have evolved the ability to derive the benzenoid moiety of the respiratory cofactor and antioxidant, ubiquinone (coenzyme Q), either from the β-oxidative metabolism of p-coumarate or from the peroxidative cleavage of kaempferol. Here, isotopic feeding assays, gene co-expression analysis and reverse genetics identified Arabidopsis 4-COUMARATE-COA LIGASE 8 (4-CL8; At5g38120) as a contributor to the β-oxidation of p-coumarate for ubiquinone biosynthesis. The enzyme is part of the same clade (V) of acyl-activating enzymes than At4g19010, a p-coumarate CoA ligase known to play a central role in the conversion of p-coumarate into 4-hydroxybenzoate. A 4-cl8 T-DNA knockout displayed a 20% decrease in ubiquinone content compared with wild-type plants, while 4-CL8 overexpression boosted ubiquinone content up to 150% of the control level. Similarly, the isotopic enrichment of ubiquinone's ring was decreased by 28% in the 4-cl8 knockout as compared with wild-type controls when Phe-[Ring-13C6] was fed to the plants. This metabolic blockage could be bypassed via the exogenous supply of 4-hydroxybenzoate, the product of p-coumarate β-oxidation. Arabidopsis 4-CL8 displays a canonical peroxisomal targeting sequence type 1, and confocal microscopy experiments using fused fluorescent reporters demonstrated that this enzyme is imported into peroxisomes. Time course feeding assays using Phe-[Ring-13C6] in a series of Arabidopsis single and double knockouts blocked in the β-oxidative metabolism of p-coumarate (4-cl8; at4g19010; at4g19010 × 4-cl8), flavonol biosynthesis (flavanone-3-hydroxylase), or both (at4g19010 × flavanone-3-hydroxylase) indicated that continuous high light treatments (500 µE m−2 s−1; 24 h) markedly stimulated the de novo biosynthesis of ubiquinone independently of kaempferol catabolism.

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