Developmental stochasticity and variation in floral phyllotaxis

Journal of Plant Research ◽

10.1007/s10265-021-01283-7 ◽

2021 ◽

Author(s):

Miho Stephanie Kitazawa

Keyword(s):

Pattern Formation ◽

Gene Networks ◽

Recent Progress ◽

Phyllotactic Pattern ◽

Floral Diversity ◽

Core Eudicots ◽

Common Process ◽

The Mean ◽

Floral Phyllotaxis ◽

Regular Patterns

AbstractFloral phyllotaxis is a relatively robust phenotype; trimerous and pentamerous arrangements are widely observed in monocots and core eudicots. Conversely, it also shows variability in some angiosperm clades such as ‘ANA’ grade (Amborellales, Nymphaeales, and Austrobaileyales), magnoliids, and Ranunculales. Regardless of the phylogenetic relationship, however, phyllotactic pattern formation appears to be a common process. What are the causes of the variability in floral phyllotaxis and how has the variation of floral phyllotaxis contributed to floral diversity? In this review, I summarize recent progress in studies on two related fields to develop answers to these questions. First, it is known that molecular and cellular stochasticity are inevitably found in biological systems, including plant development. Organisms deal with molecular stochasticity in several ways, such as dampening noise through gene networks or maintaining function through cellular redundancy. Recent studies on molecular and cellular stochasticity suggest that stochasticity is not always detrimental to plants and that it is also essential in development. Second, studies on vegetative and inflorescence phyllotaxis have shown that plants often exhibit variability and flexibility in phenotypes. Three types of phyllotaxis variations are observed, namely, fluctuation around the mean, transition between regular patterns, and a transient irregular organ arrangement called permutation. Computer models have demonstrated that stochasticity in the phyllotactic pattern formation plays a role in pattern transitions and irregularities. Variations are also found in the number and positioning of floral organs, although it is not known whether such variations provide any functional advantages. Two ways of diversification may be involved in angiosperm floral evolution: precise regulation of organ position and identity that leads to further specialization of organs and organ redundancy that leads to flexibility in floral phyllotaxis.

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Simulating Solar Global Magnetism in 3-D

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314004736 ◽

2012 ◽

Vol 10 (H16) ◽

pp. 101-103

Author(s):

A. S. Brun ◽

A. Strugarek

Keyword(s):

Magnetic Field ◽

Recent Progress ◽

Convection Zone ◽

Thermal Structure ◽

Solar Convection ◽

Self Consistent ◽

The Mean ◽

The Magnetic Field

AbstractWe briefly present recent progress using the ASH code to model in 3-D the solar convection, dynamo and its coupling to the deep radiative interior. We show how the presence of a self-consistent tachocline influences greatly the organization of the magnetic field and modifies the thermal structure of the convection zone leading to realistic profiles of the mean flows as deduced by helioseismology.

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S18-05 Exploring the space of possibilities: Gene networks for multicellular pattern formation

Mechanisms of Development ◽

10.1016/j.mod.2009.06.994 ◽

2009 ◽

Vol 126 ◽

pp. S19

Author(s):

James Sharpe

Keyword(s):

Pattern Formation ◽

Gene Networks

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The mean and noise of FPT modulated by promoter architecture in gene networks

Discrete & Continuous Dynamical Systems - S ◽

10.3934/dcdss.2019140 ◽

2019 ◽

Vol 12 (7) ◽

pp. 2177-2194

Author(s):

Kunwen Wen ◽

◽

Lifang Huang ◽

Qiuying Li ◽

Qi Wang ◽

...

Keyword(s):

Gene Networks ◽

Promoter Architecture ◽

The Mean

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Formation of sediment patterns in channel flow: minimal unstable systems and their temporal evolution

Journal of Fluid Mechanics ◽

10.1017/jfm.2017.147 ◽

2017 ◽

Vol 818 ◽

pp. 716-743 ◽

Cited By ~ 35

Author(s):

Aman G. Kidanemariam ◽

Markus Uhlmann

Keyword(s):

Pattern Formation ◽

Channel Flow ◽

Power Law ◽

Particle Diameter ◽

Migration Velocity ◽

Box Dimension ◽

Computational Domain ◽

Clear Fluid ◽

Interface Shear ◽

The Mean

The phenomenon of sediment pattern formation in a channel flow is numerically investigated by performing simulations which resolve all the relevant length and time scales of the problem. The numerical approach employed and the flow configuration considered is identical to our previous study (Kidanemariam & UhlmannJ. Fluid Mech., vol. 750, 2014, R2), the only difference being the length of the computational domain. The latter was systematically varied in order to investigate its influence on the initiation and evolution aspects. By successively reducing the streamwise length, the minimum box dimension which accommodates an unstable sediment bed is revealed, thus determining the lower threshold of the unstable modes. For the considered parameter point, the cutoff length for pattern formation lies in the range 75–100 times the particle diameter (3–4 times the clear fluid height). We also simulate the flow in a very long streamwise box with a size of 48 times the clear fluid height (featuring well over one million particles), accommodating approximately 11 initial ripple units with a wavelength in the range of 100–110 particle diameters. The evolution of the amplitude of the patterns exhibits two regimes of growth: an initial exponential regime, with a growth rate independent of the chosen domain size, and a subsequent nonlinear regime which is strongly constrained by the domain length. In the small domain cases, after the initial exponential regime, the ripples evolve steadily, maintaining their shape and migration velocity, at a mean wavelength equal to the length of the domain. The asymmetric ripple shape is characterized by a spectrum which exhibits a power-law decay over the first few dominant non-dispersive modes propagating at the mean dune migration velocity. The rate of particle transport and the mean interface shear stress exhibited an increase with increasing ripple dimensions. Nevertheless, the relationship between the two was observed to be approximately described by the empirical power-law formula for sediment transport by Wong & Parker (J. Hydraul. Engng, vol. 132, 2006, pp. 1159–1168).

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Towards the trachoma elimination target in the Southern region of Ethiopia: How well is the SAFE strategy being implemented?

The Journal of Infection in Developing Countries ◽

10.3855/jidc.11703 ◽

2020 ◽

Vol 14 (06.1) ◽

pp. 3S-9S ◽

Cited By ~ 1

Author(s):

Mekuria Asfaw ◽

Maria Zolfo ◽

Nebiyu Negussu ◽

Fantahun Tadesse ◽

Tafese Tadele ◽

...

Keyword(s):

Recent Progress ◽

Neglected Tropical Diseases ◽

Public Health Problem ◽

Tropical Diseases ◽

Improvement Strategy ◽

Active Trachoma ◽

Safe Strategy ◽

High Prevalence ◽

The Mean ◽

Low Prevalence

Introduction: Trachoma is one of the 20 neglected tropical diseases and a serious public health problem in Ethiopia. To reach the WHO elimination target by 2020, SAFE (Surgery, Antibiotics, Facial cleanliness, Environmental improvement) strategy has been implemented in the Southern Nations, Nationalities, and Peoples' Region (SNNPRs), Ethiopia. Scarce evidence exists regarding recent progress in achieving elimination of active trachoma (< 5%) and how well the SAFE strategy implemented. Methodology: A retrospective analysis of programmatic data in the period 2013-2018 was used. All trachoma endemic districts in SNNPR were included. Data collected from the Federal Ministry of Health on trachoma prevalence and SAFE strategy were analyzed. Results: Out of 134 endemic districts, only 35 had their planned impact survey, of which only 11 districts achieved the elimination target. Six districts reverted backwards from eliminated status to low (1) or moderate (5) level. The median prevalence of active trachoma in these 35 districts was 10% in 2017/18. In 2017, the mean antibiotic treatment coverage was 90%, but only 56% and 68% of districts implemented and reported on “F” and “E” components, respectively. In the high prevalence districts, only 10% delivered their planned five rounds of Zithromax® mass distribution. Conclusions: These data showed a lack in planned impact surveys with only a limited number of districts reached the WHO elimination threshold by 2018. Lack of attention on high prevalent districts, and recent reversal of trachoma eliminated districts to moderate or low prevalence levels argue for urgent and prioritized implementation of the SAFE strategy.

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Phyllotactic pattern formation in early stages of cactus ontogeny

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.2006.032 ◽

2011 ◽

Vol 75 (4) ◽

pp. 271-279 ◽

Cited By ~ 2

Author(s):

Edyta M. Gola

Keyword(s):

Pattern Formation ◽

Plant Growth ◽

Early Development ◽

Phyllotactic Pattern ◽

Early Stages ◽

Wide Range ◽

The Family

Representatives of the family Cactaceae are characterized by a wide range of phyllotaxis. To assess the origin of this diversity, early stages of phyllotactic pattern formation were examined in seedlings. The analysis of the sequence of areole initiation revealed intertribal differences. In seedlings from the Trichocereeae (Gymnocalycium, Rebutia) and Notocacteae (Parodia) tribes, two opposite cotyledonal areoles developed as the first elements of a pattern. Usually, next pair of areoles was initiated perpendicularly to cotyledonal areoles, starting the decussate pattern. This pattern was subsequently transformed into bijugate or into simple spiral phyllotaxis. In seedlings from the Cacteae tribe (Mammillaria and Thelocactus), cotyledonal areoles were never observed and the first areoles always appeared in the space between cotyledons. It was either areole pair (mainly in Mammillaria), starting a decussate pattern, or a single areole (mainly in Thelocactus) quickly followed by areoles spirally arranged, usually in accordance with the main Fibonacci phyllotaxis. Differences in the initial stages of pattern formation do not fully explain the phyllotaxis diversity in mature cacti. Only two, the most common phyllotactic patterns occurred in the early development of studied seedlings, i.e. the main Fibonacci and the decussate pattern. Discrepancy in the range of phyllotactic spectra in seedlings and in mature plants suggests that phyllotaxis diversity emerges during further plant growth. Initial phyllotactic transformations, occurring already in the very early stages, indicate great plasticity of cactus growth and seem to support the hypothesis of the ontogenetic increase of phyllotaxis diversity due to transformations.

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Modeling Post-Scratching Locomotion with Two Rhythm Generators and a Shared Pattern Formation

Biology ◽

10.3390/biology10070663 ◽

2021 ◽

Vol 10 (7) ◽

pp. 663

Author(s):

Jesus A. Tapia ◽

Argelia Reid ◽

John Reid ◽

Saul M. Dominguez-Nicolas ◽

Elias Manjarrez

Keyword(s):

Spinal Cord ◽

Pattern Formation ◽

Effective Connectivity ◽

Pattern Generator ◽

Rhythmic Movements ◽

Common Pattern ◽

The Mean ◽

Motor Outputs ◽

Mean Cycle ◽

Previous Experimental Study

This study aimed to present a model of post-scratching locomotion with two intermixed central pattern generator (CPG) networks, one for scratching and another for locomotion. We hypothesized that the rhythm generator layers for each CPG are different, with the condition that both CPGs share their supraspinal circuits and their motor outputs at the level of their pattern formation networks. We show that the model reproduces the post-scratching locomotion latency of 6.2 ± 3.5 s, and the mean cycle durations for scratching and post-scratching locomotion of 0.3 ± 0.09 s and 1.7 ± 0.6 s, respectively, which were observed in a previous experimental study. Our findings show how the transition of two rhythmic movements could be mediated by information exchanged between their CPG circuits through routes converging in a common pattern formation layer. This integrated organization may provide flexible and effective connectivity despite the rigidity of the anatomical connections in the spinal cord circuitry.

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The evolution of insect patterning mechanisms: a survey of progress and problems in comparative molecular embryology

Development ◽

10.1242/dev.1994.supplement.187 ◽

1994 ◽

Vol 1994 (Supplement) ◽

pp. 187-191

Author(s):

Klaus Sander

Keyword(s):

Pattern Formation ◽

Gene Networks ◽

Short Review ◽

Future Research ◽

Regulatory Interactions ◽

Molecular Embryology ◽

Conserved Gene ◽

Embryonic Pattern Formation

This report surveys data and interpretations presented by speakers in the Arthropod Session of the 1994 BSDB Spring Symposium. After a short review of phylogenetical aspects in premolecular insect embryology, the following topics are discussed: the ancestral germ type of pterygote insects, correlations between oogenesis and embryonic pattern formation, the universality or otherwise of bicoid as the anterior morphogen, novel functions in the insect Hox complex, the formal asymmetry between evolution and decay of complex gene networks, novel regulatory interactions as the main cause of evolutive changes, the repeated activity of conserved gene networks in successive steps of ontogenesis and strategies for future research. Interspersed are some unpublished data on oogenesis and pattern formation in lower dipterans, and their possible evolutionary implications.

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