THE GROWTH AND DIVISION OF CELLS IN RELATION TO MORPHOGENESIS IN FERN GAMETOPHYTES: II. THE EFFECT OF BIOCHEMICAL AGENTS ON THE GROWTH AND DEVELOPMENT OF PTERIDIUM AQUILINUM

1967 ◽  
Vol 45 (5) ◽  
pp. 595-603 ◽  
Author(s):  
A. E. Sobota ◽  
C. R. Partanen
Keyword(s):  
Cell Division ◽  
Cell Elongation ◽  
Growth And Development ◽  
Protein Concentration ◽  
Pteridium Aquilinum ◽  
Dimensional Structure ◽  
Cell Behavior ◽  
Differential Cell ◽  
Insight Into ◽  
Nucleic Acid Analogues

The development of the gametophyte of Pteridium aquilinum was examined in the presence of several biochemical agents. These compounds, by virtue of their influence on the processes of cell division and cell elongation, brought about a change in the gross morphology of the gametophyte. It was thus reconfirmed that a change in the form of the gametophyte may be explained in terms of differential cell behavior. This interpretation was extended to include the response of the gametophytes to several amino acid and nucleic acid analogues. It was also demonstrated that there is no quantitative increase in protein concentration associated with the development of a 2-dimensional structure and it was suggested that an examination of gametophyte morphology in terms of an interaction of cell division and cell elongation may provide a better insight into the problem of gametophyte morphogenesis.

scholarly journals Cell Elongation and Cell Death ofHelicobacter pyloriIs Modulated by the Disruption ofcdrA(Cell Division-Related Gene A)

2006 ◽  
Vol 50 (7) ◽  
pp. 487-497 ◽  
Author(s):  
Hiroaki Takeuchi ◽  
Teruko Nakazawa ◽  
Takeshi Okamoto ◽  
Mutsunori Shirai ◽  
Mitsuo Kimoto ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Division ◽  
Cell Elongation ◽  
Related Gene

scholarly journals Functional Analysis of the Mycobacterium tuberculosis FAD-Dependent Thymidylate Synthase, ThyX, Reveals New Amino Acid Residues Contributing to an Extended ThyX Motif

2008 ◽  
Vol 190 (6) ◽  
pp. 2056-2064 ◽  
Author(s):  
Jonathan E. Ulmer ◽  
Yap Boum ◽  
Christopher D. Thouvenel ◽  
Hannu Myllykallio ◽  
Carol Hopkins Sibley
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Thymidylate Synthase ◽  
Three Dimensional ◽  
Pyrimidine Ring ◽  
Dimensional Structure ◽  
Directed Mutagenesis ◽  
Catalytic Residue ◽  
Amino Acid Residues ◽  
Insight Into

ABSTRACT A novel FAD-dependent thymidylate synthase, ThyX, is present in a variety of eubacteria and archaea, including the mycobacteria. A short motif found in all thyX genes, RHRX7-8S, has been identified. The three-dimensional structure of the Mycobacterium tuberculosis ThyX enzyme has been solved. Building upon this information, we used directed mutagenesis to produce 67 mutants of the M. tuberculosis thyX gene. Each enzyme was assayed to determine its ability to complement the defect in thymidine biosynthesis in a ΔthyA strain of Escherichia coli. Enzymes from selected strains were then tested in vitro for their ability to catalyze the oxidation of NADPH and the release of a proton from position 5 of the pyrimidine ring of dUMP. The results defined an extended motif of amino acids essential to enzyme activity in M. tuberculosis (Y44X24 H69X25R95HRX7 S105XRYX90R199 [with the underlined histidine acting as the catalytic residue and the underlined serine as the nucleophile]) and provided insight into the ThyX reaction mechanism. ThyX is found in a variety of bacterial pathogens but is absent in humans, which depend upon an unrelated thymidylate synthase, ThyA. Therefore, ThyX is a potential target for development of antibacterial drugs.

Developmental studies of the stratification–germination process in sugar maple embryos

1985 ◽  
Vol 63 (5) ◽  
pp. 903-908 ◽  
Author(s):  
C. Y. Shih ◽  
E. B. Dumbroff ◽  
Carol A. Peterson
Keyword(s):  
Cell Division ◽  
Cell Elongation ◽  
Sugar Maple ◽  
Developmental Studies ◽  
Anatomical Changes ◽  
Germination Process ◽  
Radicle Protrusion ◽  
Xylem Elements ◽  
Food Reserves ◽  
Key Events

Changes in the anatomy, morphology, and stored food reserves of stratifying (5 °C) sugar maple embryos were followed from a strongly dormant state through germination. The correlation of cell division and cell elongation with radicle protrusion was also investigated. No morphological or anatomical changes were observed before first maturation of phloem elements on the 17th day of stratification. Mature xylem elements were first observed on day 37, and first germination was noted on day 38. Radicle protrusion was initiated by cell elongation, and cell division was not active for several days after emergence and a marked increase in lengths of the axes had occurred. Changes in amounts of protein, lipid, and starch were not observed during the stratification period, but mobilization of stored reserves was clearly evident with emergence of the radicles. Several of these key events appeared to be closely associated with previously described peaks and patterns of growth regulator activity.

scholarly journals A 20-bp insertion/deletion (indel) polymorphism within the <i>CDC25A</i> gene and its associations with growth traits in goat

2019 ◽  
Vol 62 (1) ◽  
pp. 353-360 ◽  
Author(s):  
Wenbo Cui ◽  
Nuan Liu ◽  
Xuelian Zhang ◽  
Yanghai Zhang ◽  
Lei Qu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Growth And Development ◽  
Marker Assisted Selection ◽  
Growth Traits ◽  
S Phase ◽  
Cashmere Goat ◽  
Indel Polymorphism ◽  
Candidate Marker ◽  
Essential Function

Abstract. Cell division cycle 25A (CDC25A), a member of the CDC25 family of phosphatases, is required for progression from G1 to the S phase of the cell cycle. CDC25A provides an essential function during early embryonic development in mice, suggesting that it plays an important role in growth and development. In this study, we used mathematical expectation (ME) methods to identify a 20-bp insertion/deletion (indel) polymorphism of CDC25A gene in Shaanbei White Cashmere (SBWC) goats. We also investigated the association between this 20-bp indel and growth-related traits in SBWC goats. Association results showed that the indel was related to growth traits (height at hip cross, cannon circumference, and cannon circumference index) in SBWC goats. The height at hip cross of individuals with insertion/insertion (II) genotype was higher than those with insertion/deletion (ID) genotype (P=0.02); on the contrary, the cannon circumference and cannon circumference index of individuals with ID genotype were superior when compared with those with II genotype (P=0.017 and P=0.009). These findings suggest that the 20-bp indel in the CDC25A gene significantly affects growth-related traits, and could be utilized as a candidate marker for marker-assisted selection (MAS) in the cashmere goat industry.

Learning for Another: From Self-Interest to Altruism

2015 ◽  
Vol 57 (3) ◽  
pp. 252-280 ◽  
Author(s):  
Aaron W. Snyder ◽  
Stephen C. Yanchar ◽  
Edwin E. Gantt
Keyword(s):  
Qualitative Study ◽  
Growth And Development ◽  
Learning Experiences ◽  
Case Analysis ◽  
Communal Learning ◽  
Self Interest ◽  
Cross Case Analysis ◽  
Insight Into

This qualitative study offers an examination of the learning experiences of six individuals, each of whom initially learned for self-interested purposes, but later experienced a shift in their desire and pursued learning to benefit others. We conducted interviews that described this phenomenon and provided insight into the following question: What is the experience of a learner who transitions from learning out of self-interest to learning for the sake of another? Findings of this study include narrative case summaries for each participant and a cross-case analysis that includes six major themes regarding participants’ transition to altruistic forms of learning: humility as a prerequisite, communal learning, emphasis on the success of others, becoming more self-confident, becoming a more effective learner, and becoming more other centered. Overall, participants in this study found the most meaning by helping recipients achieve their own growth and development rather than by merely accomplishing tasks.

Anatomy of Wild Garlic Bulbs During and Subsequent to After-Ripening

Weed Science ◽  
1972 ◽  
Vol 20 (3) ◽  
pp. 233-237 ◽  
Author(s):  
J. F. Stritzke ◽  
E. J. Peters
Keyword(s):  
Cell Division ◽  
Microscopic Examination ◽  
Cell Elongation ◽  
Leaf Primordia ◽  
Root Primordia ◽  
Ripening Period ◽  
Shoot Primordia ◽  
Division Cell ◽  
Wild Garlic

Microscopic examination of central and soft offset bulbs of wild garlic(Allium vinealeL.) at senescence of the parent plants in May and June revealed embryonic plants with numerous root primordia and four or five shoot primordia. Hardshell bulbs and aerial bulblets contained only one or two root primordia and three leaf primordia. The embryonic plants of central, soft offset, and hardshell bulbs elongated slowly during the after-ripening period. Rapid cell division, cell elongation, and initiation of new leaves took place after termination of the after-ripening period in all but the dormant hardshell bulbs. In November, new hardshell bulbs could be seen at the base of plants developed from central and soft offset bulbs.

scholarly journals A Positive Tropism of Rice Roots toward a Nutrient Source

2019 ◽  
Vol 61 (3) ◽  
pp. 546-553
Author(s):  
Kiyoshi Yamazaki ◽  
Yoshihiro Ohmori ◽  
Toru Fujiwara
Keyword(s):  
Cell Elongation ◽  
Lateral Roots ◽  
Fourth Power ◽  
Nutrient Concentrations ◽  
Root Tips ◽  
High Moisture ◽  
Nutrient Source ◽  
Directional Growth ◽  
Rice Roots ◽  
Differential Cell

Abstract Plants take up water and nutrients through roots, and uptake efficiency depends on root behavior. Roots recognize the moisture gradient in the soil and grow toward the direction of high moisture. This phenomenon is called hydrotropism, and it contributes to efficient water uptake. As nutrients in soil are also unevenly distributed, it is beneficial for plants to grow their roots in the direction of increasing nutrient concentrations, but such a phenomenon has not been demonstrated. Here, we describe the directional growth of roots in response to a nutrient gradient. Using our assay system, the gradient of a nitrogen nutrient, NH4+, was sufficient to stimulate positive tropic responses of rice lateral roots. This phenomenon is a tropism of plant roots to nutrients; hence, we propose the name ‘nutritropism’. As well as other tropisms, differential cell elongation was observed before the elongation zone during nutritropism, but the pattern promoting cell elongation preferentially on the non-stimulated side was opposite to those in root hydrotropism and gravitropism. Our evaluation of the NH4+ gradient suggested that the root tips responded to a sub-micromolar difference in NH4+ concentration on both sides of the root. Hydrotropism, gravitropism and phototropism were described in plants as the ‘power of movement’ by Charles and Francis Darwin in 1880, and these three tropisms have attracted the attention of plant scientists for more than 130 years. Our discovery of nutritropism represents the fourth ‘power of movement’ in plants and provides a novel root behavioral property used by plants to acquire nutrients efficiently.

Realising Value from Absorptive Capacity

2018 ◽  
Vol 17 (01) ◽  
pp. 1850011
Author(s):  
Ronald Eastburn
Keyword(s):  
Absorptive Capacity ◽  
Dimensional Structure ◽  
Community Banks ◽  
Innovative Performance ◽  
Future Studies ◽  
Community Bank ◽  
Knowledge Based ◽  
Formal Mechanism ◽  
Improved Performance ◽  
Insight Into

To gain insight into how successful community banks are continuously “adaptive” to environmental challenges, we examined the role absorptive capacity (ACAP) plays in effecting improved performance. ACAP is the formal mechanism used for sensing and experimentation of knowledge — and as such is adopted to acquire, assimilate, transform and exploit knowledge so as to positively influence performance. Data obtained from a survey of 151 community bank CEOs confirmed that ACAP does indeed enhance performance. We also demonstrated the multi-dimensional structure of ACAP, the consequence of cultivating an active learning orientation and the relevance of potential cultural inhibitors on decision behaviour for innovative performance. Several directions for future studies utilising knowledge-based responses are proposed.

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