An overview of pigment gland morphogenesis and its regulatory mechanism

Cotton has enormous economic potential,providing high-quality protein,oil,and fibre.But the comprehensive utilization of cottonseed is limited by the presence of pigment gland and its inclusion.Pigment gland is a common characteristic of Gossypium genus and its relatives,appearing as visible dark opaque dots in most tissues and organs of cotton plants.Secondary metabolites,such as gossypol,synthesized and stored in the cavities of pigment glands act as natural phytoalexins,but are toxic to humans and other monogastric animals.However,only a few cotton genes have been identified as being associated with pigment gland morphogenesis to date,and the developmental processes and regulatory mechanism involved in pigment gland formation remain largely unclear.Here,the research progress on the process of pigment gland morphogenesis and the genetic basis of cotton pigment glands is reviewed,for providing a theoretical basis for cultivating cotton with the ideal pigment gland trait.

Hepatitis B virus morphogenesis

The hepatitis B virus （HBV） particle consists of an envelope containing three related surface proteins and probably lipid and an icosahedral nucleocapsid of approximately 30 nm diameter enclosing the viral DNA genome and DNA polymerase. The capsid is formed in the cytosol of the infected cell during packaging of an RNA pregenome replication complex by multiple copies of a 21-kDa C protein. The capsid gains the ability to bud during synthesis of the viral DNA genome by reverse transcription of the pregenome in the lumen of the particle. The three envelope proteins S, t4, and L shape a complex transmembrane fold at the endoplasmic reticulum, and form disulfide-linked homoand heterodimers. The transmembrane topology of a fraction of the large envelope protein L changes posttranslationally, therefore, the N terminal domain of L （preS） finally appears on both sides of the membrane. During budding at an intracellular membrane, a short linear domain in the cytosolic preS region interacts with binding sites on the capsid surface. The virions are subsequently secreted into the blood. In addition, the surface proteins can bud in the absence of capsids and form subviral lipoprotein particles of 20 nm diameter which are also secreted.

The autophagy gene ATG8 affects morphogenesis and oxidative stress tolerance in Sporisorium scitamineum

The basidiomycetous fungus Sporisorium scitamineum causes sugarcane smut that leads to severe economic losses in the major sugarcane growing areas in China,India and Brazil,etc.Autophagy is a conserved pathway in eukaryotes for bulk degradation and cellular recycling,and was shown to be important for fungal cell growth,development,and pathogenicity.However,physiological function of autophagy has not been studied in S.scitamineum.In this study,we identified a conserved Atg8 protein,named as SsAtg8 and characterized its function.Our results showed that autophagy was blocked in the ssatg8Δ mutant,in nitrogen starvation.The ssatg8Δ mutant formed pseudohypha frequently and was hypersensitive to oxidative stress.However,mating or filamenation was unaffected in the ssatg8Δ mutant in vitro.Overall we demonstrate that autophagy is dispensable for S.scitamineum mating/filamentation,while critical for oxidative stress tolerance and proper morphology in sporidial stage.

FACEts of mechanical regulation in the morphogenesis of craniofacial structures

During embryonic development,organs undergo distinct and programmed morphological changes as they develop into their functional forms.While genetics and biochemical signals are well recognized regulators of morphogenesis,mechanical forces and the physical properties of tissues are now emerging as integral parts of this process as well.These physical factors drive coordinated cell movements and reorganizations,shape and size changes,proliferation and differentiation,as well as gene expression changes,and ultimately sculpt any developing structure by guiding correct cellular architectures and compositions.In this review we focus on several craniofacial structures,including the tooth,the mandible,the palate,and the cranium.We discuss the spatiotemporal regulation of different mechanical cues at both the cellular and tissue scales during craniofacial development and examine how tissue mechanics control various aspects of cell biology and signaling to shape a developing craniofacial organ.

Auxin regulation involved in gynoecium morphogenesis of papaya flowers

The morphogenesis of gynoecium is crucial for propagation and productivity of fruit crops.For trioecious papaya(Carica papaya),highly differentiated morphology of gynoecium in flowers of different sex types is controlled by gene networks and influenced by environmental factors,but the regulatory mechanism in gynoecium morphogenesis is unclear.Gynodioecious and dioecious papaya varieties were used for analysis of differentially expressed genes followed by experiments using auxin and an auxin transporter inhibitor.We first compared differential gene expression in functional and rudimentary gynoecium at early stage of their development and detected significant difference in phytohormone modulating and transduction processes,particularly auxin.Enhanced auxin signal transduction in rudimentary gynoecium was observed.To determine the role auxin plays in the papaya gynoecium,auxin transport inhibitor(N-1-Naphthylphthalamic acid,NPA)and synthetic auxin analogs with different concentrations gradient were sprayed to the trunk apex of male and female plants of dioecious papaya.Weakening of auxin transport by 10 mg/L NPA treatment resulted in female fertility restoration in male flowers,while female flowers did not show changes.NPA treatment with higher concentration(30 and 50 mg/L)caused deformed flowers in both male and female plants.We hypothesize that the occurrence of rudimentary gynoecium patterning might associate with auxin homeostasis alteration.Proper auxin concentration and auxin homeostasis might be crucial for functional gynoecium morphogenesis in papaya flowers.These results will lead to further investigation on the auxin homeostasis and gynoecium morphogenesis in papaya.

STUDIES ON THE CORtICAL MORPHOGENESIS DURINg CELL DIVISION IN HaLTErIA GRANDINELLA(MULLER, 1773)(CILIOPHORA,OLIGOTRICHIDA)

Morphogenesis during cell division was investigated in oligotrichous ciliate,Halteria grandinella utilizing protargol impregnated specimens. The cortical morphogenetical pattern of Hdteria grandinella is generally similar to that given by Faure-Fremiet. The prater inherits the parental adoral zone of membranelles (AZM) appar ently unchanged; in the opisthe the oral primordium develops de novo from a single AZM-anlage; somatic cirri for both the proter and opisthe are separately differentiated from 10 (seldom 9) cirral primordia that originate de novo from 10 latitudinal developmental anlagen. The anlage of paroral membrane of opisthe forms just to the right of the posterior end of the oral primordium. Each streak of cirral primordia develops 4 groups of basal body pairs: both of the anterior two consist of only one pair of basal bodies, on the contrary, each of the last two groups has 2 basal body pairs.

Morphogenesis,Anatomical Observation and Primary Genetic Analysis of a Multi-glume Floral Organ Mutant in Rice

A multi-glume （mg） mutant was obtained by screening the T-DNA inserted mutant pool. Anatomical observation revealed that the florets of the mutant showed elongated leafy paleas/lemmas and palea/lemma-like structures, just like multi-glumes. Among the 215 observed florets of the mutant, 14.27% were failed to produce pistil and stamens, 23.72% showed extra floret generated on the same rachilla, while 62.01% consisted of one to nine stamens and one to three pistils in a single floret. On the other hand, in some cases the transparent bulged vesile-like tissue could be observed at the basis of filament. The mutant showed glumaceous Iodicules, which prevented the florets from opening in natural conditions, while the absolute male and female sterility was an obvious character of the current mutant. Observation on the process of floral organ morphogenesis by a scanning electron microscopy （SEM） indicated that no phenotype difference in floret primordia was found between the wild-type and the mutant. Meanwhile, for the mutant, the beginning of stamen and pistil primordial differentiation was later than the wild type and the palea/lemma-like structure continued to differentiate after the formation of normal palea and lemma. Furthermore, in the mutant the asymmetrical division of floral primordial caused variation in the number of stamens and pistils. Therefore, the genetic analyses indicated that the mutation phenotype was a recessive trait controlled by a single gene and co-segregated with the T-DNA. Based on the phenotypic characteristics, it could be deduced that the mutant was the result of homeotic conversion from the function of the class E genes in ABCD model.

Divisional morphogenesis in the marine ciliate Anteholosticha manca (Kahl,1932) Berger,2003 (Ciliophora:Urostylida)

The cortical development and macronuclear evolution of the marine hypotrichous ciliate Anteholosticha manca, collected from the coastal waters near Qingdao, China, were investigated using the protargol impregnation method. The morphogenesis of A. manca is generally typical for the genus, and can be characterized as the following features ： （ 1 ） in the proter, a new oral primordium is formed on the bottom （beneath the pellicle） of the buccal cavity, disorganization of the parental undulating membranes do not contribute to the formation of this primordium ; （2） FVT-cirral anlagen in both dividers develop independently, and very likely only a few midventral cirri join in the formation of these primordia; （ 3 ） both marginal row and dorsal kinety anlagen develop intrakinetally within the parental structure; （4） at the middle stage, macronuclear segments fuse together to form a single mass as observed in most of its related forms.

Structural Topology Optimization Method for Morphogenesis of Dendriforms

The topology optimization method of continuum structures is adopted for the morphogenesis of dendriforms during the conceptual design phase. The topology optimization model with minimizing structural strain energy as objective and subject to structural weight constraint is established by the independent continuous mapping method (ICM) which is a popular and efficient method for the topology optimization of continuum structures. This optimization model is an optimization problem with a single constraint and can be solved by the iteration formula established based on the saddle condition. Taking the morphogenesis of a plane dendriform as an example, the influences on topologies of the dendriform are discussed for several factors such as the ratio of the reserved weight to the total weight, the stiffness and the geometry shape of the roof structure, the height of the design area, and so on. And several examples of application scenarios are presented, too. Numerical examples show that the proposed structural topology optimization method for the morphogenesis of dendriforms is feasible. It can provide diversiform topologies for the conceptual design of dendriforms.

The roles of tubulin-folding cofactors in neuronal morphogenesis and disease

Microtubules play important roles in neuronal morphogenesis, including cellular polarization, neurite growth, and branching. A microtubule is a polymer of a- and β-tubulin heterodimers that are formed by a multistep process assisted by at least five tubulin-fold- ing cofactors （TBCA-E） （Lopez-Fanarraga et al., 2001）. Newly syn- thesized α- and β-tubulins associate with the cytosolic chaperonin complex （CCT）, and then the quasi-native tubulins interact with five tubulin-folding cofactors. The α- and β-tubulins first interact with TBCB and TBCA, which are further transferred to TBCE and TBCD, respectively. The α- and β-tubulins, TBCC, TBCD, and TBCE form a supercomplex, and guanosine triphosphate （GTP） hydrolysis occurs within the supercomplex, releasing a tubulin heterodimer. In addition to their functions in tubulin folding and tubulin heterodimer formation, excess amounts of TBCD or TBCE may interact with tubulin heterodimers, leading to their degrada- tion. Thus, tubulin-folding cofactors may play a role in both the synthesis and degradation of tubulin heterodimers.

Influence of Environmental Conditions on Morphogenesis and on Changes of Primary and Secondary Metabolites in Asclepias syriaca L, Derived in Vitro

The object of this study was to adapt in vitro system for morphogenesis and regeneration of microshoots of common milkweed （Asclepias syriaca L.） applying different concentrations of hydrogen ion （H＋） and cytokinin 6-benzylaminopurine （BAP）. The influence of BAP and hydrogen ion （H＋） on the level of primary （chlorophyll a, chlorophyll b and carotenoids） and secondary （flavonoids and hydrolyzable and condensed tannins） metabolites in in vitro grown Asclepias syriaca L, were evaluated. Six different concentrations of BAP （0, 1, 2, 3, 4 and 5 ~tmol/L） and three different concentrations of hydrogen ion （pH 4.5, 5.0 and 5.5） were applied to the woody plant medium （WPM） medium used for microshoots propagation. The most effective morphogenesis of Asclepias syriaca L. was observed in culture medium supplemented with 2 p, mol/L BAP. However, synthesis of primary and secondary metabolites was the most intensive when cytokinin concentration reached the value of 3 gmol/L BAP. It was determined that the activity of hydrogen ion （H＋）, measured as the pH of culture medium, had a significant effect on secondary metabolites in the shoots in vitro.

Contributions of the GIS and the MNT in the Study of the Landscape Morphogenesis of the Area Goulmima-Errachidia (Morocco)

Oasis of the Rheris is located in the South-East of Morocco in the province of Errachidia, in the region of Draa-Tafilalt. This zone of study contains in its administrative unit the municipality of Goulmima, and two rural communes: Gheris El Ouloui and Gheris Essoufli. The cretaceous basin of Gheris constitutes of the principal geomorphological entities is limited by the carbonated Jurassic High-Atlas in Tadighoust in north and west. In the south, the Anti-Atlas chain of Mellab and Tinjdad is dominated by a Precambrian base which supports with its back a thick cover of the Paleozoic. And in the center there is Rheris Oasis which characterizes this bioclimatic zone. This oasis looks like an island in the saharan desert. Finally, Hammada de Meski is located in the east. In the tourist literature of Morocco, it mentions the gravitational landscapes in the south of Morocco, of which are geomorphosites of Goulmima that offer superb landscapes. From my point of view, the primary reason behind this research task is to promote geo-eco-tourism for sustainable development of this area. Several tourists cross the zone of study, especially Amellagou-Tinjdad circuit because they are attracted much when they arrive at the beautiful landscape of Rheris, such as geomorphlogical landscape (Tifounassine: full of fresh water). There are many other sources like Tamda N’mssoud, Boukhazm and Asdram of a distance from important observation which offers a beautiful vision on the synclinorium infracenomanian. According to Panizza (2001), the geomorphosites are forms of the relief which have acquired a scientific, cultural and historical, aesthetic, didactic and/or socio-economic value because of their perception. The cartography of the geomorphosites fundamentally aims at giving to the users an immediate perception of the space distribution and representation of the forms of the relief [1]. Today, the use of the Geographical Information Systems has acquired an important growing because of the possibilities of update and interaction with the user with a view to natural regional planning. The digital models of ground (MNT), extracted from the satellite pictures offer valuable help for the analysis and the detailed cartography of the reliefs. The GIS applied to the geographical zone of Goulmima led to the construction and the reading of the results produced by several cards sets of themes.

Individual differences determine the morphogenesis pattern and reproductive uniqueness of the invasive green macroalga,implications for its habitat adaptation

The marine green algae genus Chaetomorpha is a common source of“green tide”and is widespread on coasts around the world.In this study,based on invasive Chaetomorpha valida collected from the Shandong Peninsula,the morphogenesis and reproductive characteristics of two strains that are morphologically different from each other,were observed using experimental biology methods.The main results are as follows:(1)significant difference in the size of reproductive cells produced by Strains 1 and 2;(2)gametes produced by Strain 2 are isogamous and same gametangial during the binding process of gametes,whereas those of Strain 1 are isogamous but hetero-cystic;(3)progeny from Strain 1 has rhizoidal holdfast,whereas that of Strain 2 has discoid holdfast;(4)gametophytic“branching”was found in Strain 1.These results could validate the high phenotypic plasticity of macroalgae and offered an interpretation of habitat adaptation.Furthermore,this study innovatively provided fundamental research on the selection of macroalgal traits and explored competitive strategies for the dominant survival of macroalgae from a new perspective.

Molecular Mechanisms of Leaf Morphogenesis

Plants maintain the ability to form lateral appendages throughout their life cycle and form leaves as the principal lateral appendages of the stem. Leaves initiate at the peripheral zone of the shoot apical meristem and then develop into flattened structures. In most plants, the leaf functions as a solar panel, where photosynthesis converts carbon dioxide and water into carbohydrates and oxygen. To produce structures that can optimally fulfill this function, plants precisely control the initiation, shape, and polarity of leaves. Moreover, leaf development is highly flexible but follows common themes with conserved regulatory mechanisms. Leaves may have evolved from lateral branches that are converted into determinate, flattened structures. Many other plant parts, such as floral organs, are considered specialized leaves, and thus leaf development underlies their morphogenesis. Here, we review recent advances in the understanding of how threedimensional leaf forms are established. We focus on how genes, phytohormones, and mechanical properties modulate leaf development, and discuss these factors in the context of leaf initiation, polarity establishment and maintenance, leaf flattening, and intercalary growth.

Notch signaling in blood vessels: from morphogenesis to homeostasis

Notch signaling is an evolutionarily conserved intercellular signaling pathway that plays numerous crucial roles in vascular development and physiology.Compelling evidence indicates that Notch signaling is vital for vascular morphogenesis including arterial and venous differentiation and endothelial tip and stalk cell specification during sprouting angiogenesis and also vessel maturation featured by mural cell differentiation and recruitment.Notch signaling is also required for vascular homeostasis in adults by keeping quiescent phalanx cells from re-entering cell cycle and by modulating the behavior of endothelial progenitor cells.We will summarize recent advances of Notch pathway in vascular biology with special emphasis on the underlying molecular mechanisms.

Hormonal Regulation of Leaf Morphogenesis in Arabidopsis

Leaf morphogenesis is strictly controlled not only by intrinsic genetic factors, such as transcriptional factors, but also by environmental cues, such as light, water and pathogens. Nevertheless, the molecular mechanism of how leaf morphogenesis is regulated by genetic programs and environmental cues is far from clear. Numerous series of events demonstrate that plant hormones, mostly small and simple molecules, play crucial roles in plant growth and development, and in responses of plants to environmental cues such as light. With more and more genetics and molecular evidence obtained from the model plant Arabidopsis, several fundamental aspects of leaf morphogenesis including the initiation of leaf primordia, the determination of leaf axes, the regulation of cell division and expansion in leaves have been gradually unveiled. Among these phytohormones, auxin is found to be essential in the regulation of leaf morphogenesis.

Low concentrations of atrazine,glyphosate,2,4-dichlorophenoxyacetic acid,and triadimefon exposures have diverse effects on Xenopus laevis organ morphogenesis

Many chemicals are released into the environment, and chemical contamination has been suggested as a contributing factor to amphibian declines. To add to a growing body of knowledge about the impact of individual chemicals on non-target organisms, we examined the specificity of deformities induced by exposure to four pesticides （atrazine, 2,4-dichloropheoxyacetic acid （2,4-D）, triadimefon, and glyphosate） in the model amphibian species, Xenopus laevis. We focused on the period of organ morphogenesis, as it is frequently found to be particularly sensitive to chemical exposure yet also commonly overlooked. We found similar levels of intestine malformations and edemas, as well as disruption of skeletal muscle, in atrazine and triadimefon exposed tadpoles. The effects of 2,4-D were only apparent at the highest concentrations we examined; glyphosate did not induce dramatic malformations at the concentrations tested. While researchers have shown that it is important to understand how chemical mixtures affect non-target organisms, our results suggest that it is first crucial to determine how these chemicals act independently in order to be able to identify consequences of individual pesticide exposure.

Plant Morphogenesis 123: a renaissance in modern botany?

Plants are a group of multicellular organisms crucial for the biosphere on the Earth. In the 17 th century, the founding fathers of modern botany viewed the bud as the basic unit undergoing the plant life cycle. However, for many understandable reasons, the dominant conceptual framework evolved away from the "bud-centered" viewpoint to a "plant-centered" viewpoint that treated the whole plant, consisting of numerous buds, as a unit and considered the entire plant to be the functional equivalent of an animal individual. While this "plant-centered" viewpoint is convenient and great progress has been made using this conceptual framework, some fundamental problems remain logically unsolvable. Previously, I have proposed a new conceptual framework for interpretation of plant morphogenesis, called Plant Morphogenesis 123, which revives a "bud-centered" viewpoint. The perspective of Plant Morphogenesis 123 allows us to address new questions regarding to the mechanisms of plant morphogenesis that are important, and technically accessible, but previously neglected under the "plant-centered" conceptual framework. In addition to describing these questions, I address a more fundamental question for further discussion: why do people study plants?

Morphogenesis of Pistillate Flowers of Cercidiphyllum japonicum(Cercidiphyllaceae)

Floral morphogenesis and the development of Cercidiphyllumjaponicum Sieb. et Zucc. were observed by scanning electron microscopy （SEM）. The results showed that the pistillate inflorescences were congested spikes with the flowers arranged opposite. Great differences between the so-called ＂bract＂ and the vegetative leaf were observed both in morphogenesis and morphology. In morphogenesis, the ＂bract＂ primordium is crescent-shaped, truncated at the apex and not conduplicate, has no stipule primordium at the base but does have some inconspicuous teeth in the margin that are not glandular. The leaf primordium is triangular, cycloidal at the apex, conduplicate, has two stipule primordia at the base, has one gland-tooth at the apex occurring at first and some gland-teeth in the margin that occur later. In morphology, the ＂bract＂ is also different to the vegetative leaf in some characteristics that were also illustrated in the present paper. Based on the hypothesis that the bract is more similar to the vegetative leaf than the tepal, we considered that the so-called ＂bract＂ of C.japonicum might be the tepal of the pistillate flower in morphological nature. Therefore, each pistillate flower contains a tepal and a carpel. We did not find any trace of other floral organs in the morphogenesis of the pistillate flower. Therefore we considered that the unicarpellate status of extant Cercidiphyllum might be to highly reduce and advance characteristics that make the extant Cercidiphyllum isolated from both fossil Cercidiphyllum-like plants and its extant affinities.

A Single-cell Transcriptome Atlas of Cashmere Goat Hair Follicle Morphogenesis

Cashmere,also known as soft gold,is produced from the secondary hair follicles(SHFs)of cashmere goats.The number of SHFs determines the yield and quality of cashmere;therefore,it is of interest to investigate the transcriptional profiles present during cashmere goat hair follicle development.However,mechanisms underlying this development process remain largely unexplored,and studies regarding hair follicle development mostly use a murine research model.In this study,to provide a comprehensive understanding of cellular heterogeneity and cell fate decisions,single-cell RNA sequencing was performed on 19,705 single cells of the dorsal skin from cashmere goat fetuses at induction(embryonic day 60;E60),organogenesis(E90),and cytodifferentiation(E120)stages.For the first time,unsupervised clustering analysis identified 16 cell clusters,and their corresponding cell types were also characterized.Based on lineage inference,a detailed molecular landscape was revealed along the dermal and epidermal cell lineage developmental pathways.Notably,our current data also confirmed the heterogeneity of dermal papillae from different hair follicle types,which was further validated by immunofluorescence analysis.The current study identifies different biomarkers during cashmere goat hair follicle development and has implications for cashmere goat breeding in the future.