Ovule ontogeny of Tabebuia pulcherrima Sandwith (Bignoniaceae): embryo sac development

The chalazal megaspore develops in a Polygonum-type embryo sac. The amyloplast-rich endothelium is partially degraded during the expansion of the micropylar portion of the megagametophyte. Organization of the mature embryo sac is determined by the patterns of vacuolation, nuclear migration, spindle orientation and cellularization. The egg cell is slightly chalazal in relation to the synergids, and its micropylar end does not touch the micropylar channel. At the chalazal pole of the egg apparatus, the common walls between the synergids, the egg and central cells, despite their tenuity, are present in the mature megagametophyte. The polar nuclei do not fuse before fertilization and the antipodals are persistent until the first stages of endosperm formation. The taxonomic significance of some embryological characters for the Bignoniaceae is discussed.

Morphological development of Corydoras aff. paleatus (Siluriformes, Callichthyidae) and correlation with the emergence of motor and social behaviors

Here we examine major anatomical characteristics of Corydoras aff. paleatus (Jenyns, 1842) post-hatching development, in parallel with its neurobehavioral evolution. Eleutheroembryonic phase, 4.3-8.8 days post-fertilization (dpf); 4.3-6.4 mm standard length (SL) encompasses from hatching to transition to exogenous feeding. Protopterygiolarval phase (8.9-10.9 dpf; 6.5-6.7 mm SL) goes from feeding transition to the commencement of unpaired fin differentiation, which marks the start of pterygiolarval phase (11-33 dpf; 6.8-10.7 mm SL) defined by appearance of lepidotrichia in the dorsal part of the median finfold. This phase ends with the full detachment and differentiation of unpaired fins, events signaling the commencement of the juvenile period (34-60 dpf; 10.8-18.0 mm SL). Eleutheroembryonic phase focuses on hiding and differentiation of mechanosensory, chemosensory and central neural systems, crucial for supplying the larval period with efficient escape and nutrient detection-capture neurocircuits. Protopterygiolarval priorities include visual development and respiratory, digestive and hydrodynamic efficiencies. Pterygiolarval priorities change towards higher swimming efficacy, including carangiform and vertical swimming, necessary for the high social interaction typical of this species. At the end of the protopterygiolarval phase, simple resting and foraging aggregations are seen. Resting and foraging shoals grow in complexity and participant number during pterygiolarval phase, but particularly during juvenile period.

Embryonic development of human lice: rearing conditions and susceptibility to spinosad

The embryonic development of human lice was evaluated according to the changes in the morphology of the embryo observed through the transparent chorion. Based on ocular and appendage development, three stages of embryogenesis were established: early, medium, and late. Influence of temperature and relative humidity (RH) on the laboratory rearing of Pediculus humanus capitis eggs was assessed. The optimal ranges for temperature and RH were 27-31°C and 45-75%. The susceptibility of human louse eggs to insecticide spinosad (a macrocyclic lactone) was assessed by immersion method. The results showed similar susceptibility to spinosad in early, medium, and late stages of head lice eggs. In addition, this study showed similar susceptibility of head and body lice eggs to spinosad, an insecticide that has not been used as pediculicide in Argentina (lethal concentration 50: 0.01%).

Carbon sources and polyethylene glycol on soybean somatic embryo conversion

Somatic embryogenesis is an efficient method for the production of target cells for soybean genetic transformation. However, this method still offers low percentages of plant regeneration, and perhaps is related to the maturation process and high morphological abnormalities of the matured embryos. This study aimed to identify a maturation medium that could contribute to the outcome of more efficient plant regeneration results. Embryogenic clusters, derived from cotyledons of immature seeds of the soybean cultivars Bragg and IAS5, were used as starting material for embryos development. Different maturation media were tested by using 6% maltose, 3% sucrose or 6% sucrose, combined with or without 25 g L-1 of the osmotic regulator polyethylene glycol (PEG-8000). The histodifferentiated embryos were quantified and classified in morphological types. Percentages of converted embryos were analyzed. Cultivar Bragg resulted in higher matured embryo quantities, but lower percentages were obtained for the conversion in comparison to cultivar IAS5. While the addition of PEG did not affect the number of embryos converted into plants, 6% sucrose enhanced the conversion percent significantly.

Embryo rescue from interspecific crosses in apple rootstocks

The objetive of this work was to rescue immature embryos of apple rootstocks Malus prunifolia (Marubakaido) and Malus pumila (M9) after 40-60 days of pollination and to put them into MS culture media supplemented with agar (6 g L-1) and casein hydrolysate (500 mg L-1). Embryos originated from interspecific crosses and open pollination showed differences in the in vitro responses, depending on the female parent, the developmental stage of the embryo, and the culture medium composition. Embryos of the M. pumila rootstock, rescued within 40 days after pollination and put in culture medium supplemented with indolacetic acid (IAA), gibberellic acid (GA3), kinetin and maltose, resulted in a normal development of plantlets. However, embryos originating from hand-pollination, cultivated in medium supplemented with 14 µM IAA, 5 µM kinetin and 1.5 µM Ga3 (MS1), mainly those of M. prunifolia x M. pumila, showed a high percentage of rusted embryos (96.2%). Embryos from open pollination of M. prunifolia and M. pumila formed calluses. It was possible to identify the influence of the female parent by the enhanced development of M. pumila shoots derived from open or hand-pollination. The crossing of responsive species and the use of the technique of embryo culture provided a rapid and uniform germination and, consequently, the development of fully normal seedlings.

Development of globular embryos from the hybridization between 'Pêra Rio' sweet orange and 'Poncã' mandarin

This research was undertaken to study the influence of different concentrations of the MT medium, sucrose, vitamins, activated charcoal and gibberellic acid (GA3) on the culture of immature embryos from the crossing between 'Pêra Rio' sweet orange and 'PONCÃ' mandarin. The embryos were excised under aseptic conditions and inoculated in 15 mL of the MT medium according to the following experiments: 1) MT concentrations (0%, 50%, 100%, 150% and 200%) supplemented with 0, 30, 60 and 90 g.L-1 of sucrose; 2) vitamins concentrations of the MT (0%, 50%, 100%, 150% and 200%) supplemented with 0, 30, 60 and 90 g.L-1 of sucrose; 3) activated charcoal concentrations (0, 0.5, 1, 1.5 and 2 g.L-1) supplemented with GA3 (0, 0.01, 0.1; 1 and 10 mg.L-1). After the inoculation, the embryos were kept in a growth room for 90 days at 27 ± 1ºC, in a 16-hour photoperiod with 32 µmol.m-2.s-1 of irradiance. The best development of embryos at the globular stage was achieved using 50% and 100% of the MT medium plus 60 g.L-1 and 90 g.L-1 of sucrose, respectively, supplemented with 0.01 mg.L-1 of GA3. The addition of activated charcoal or vitamins in the MT medium has shown to be unnecessary to the development of globular embryos.

Assessment of embryo/fetus during pregnancy by threedimensional ultrasonography using the HD live software: iconographic essay

Fetal development is studied since the advent of two-dimensional ultrasonography. However, a detailed assessment of structures and surfaces improved with three-dimensional ultrasonography. Currently, it is possible to identify embryonic components and fetal parts with greater detail, at all pregnancy trimesters, using the HD live software, where the images gain realistic features by means of appropriate control of lighting and shadowing effects. In the present study, the authors utilized this resource to follow-up, by means of images, the development of a normal pregnancy along all trimesters.

Development of virus resistant transgenic papayas expressing the coat protein gene from a Brazilian isolate of Papaya ringspot virus

Translatable and nontranslatable versions of the coat protein (cp) gene of a Papaya ringspot virus (PRSV) isolate collected in the state of Bahia, Brazil, were engineered for expression in Sunrise and Sunset Solo varieties of papaya (Carica papaya). The biolistic system was used to transform secondary somatic embryo cultures derived from immature zygotic embryos. Fifty-four transgenic lines, 26 translatable and 28 nontranslatable gene versions, were regenerated, with a transformation efficiency of 2.7%. Inoculation of cloned R0 plants with PRSV BR, PRSV HA or PRSV TH, Brazilian, Hawaiian and Thai isolates, respectively, revealed lines with mono-, double-, and triple-resistance. After molecular analysis and a preliminary agronomic evaluation, 13 R1 and R2 populations were incorporated into the papaya-breeding program at Embrapa Cassava and Tropical Fruits, in Cruz das Almas, Bahia, Brazil.

Ovule ontogeny of Tabebuia pulcherrima Sandwith (Bignoniaceae): megasporogenesis and integument development

The ovule of Tabebuia pulcherrima is anatropous, unitegmic and tenuinucellate. The nucellus shows a trizonate structural organization. The integument is initiated by periclinal divisions in the dermal layer (zone I), around the base of the archesporium. Subsequently, cells derived from the subdermal layer (zone II) start to push the dermal cells, so that they shift toward the micropylar region. The archesporial cell differentiates directly into the megaspore mother cell, undergoes meiosis, and originates a linear tetrad of megaspores. The mature embryo sac mother cell is elongated, possess a conspicuous central nucleus, and a characteristic bipolar vacuome with fibrous-granulated content. The inner cell layers of the integument differentiate into an amyloplast-rich endothelium. Patterns of callose deposition in the tetrad and selection of the functional megaspore, as well as the taxonomic value of some characters are discussed.

Morphology and anatomy of the fruit and seed in development of Chorisia speciosa A. St.-Hil. - Bombacaceae

The structure of the fruit and seed in development of Chorisia speciosa are described with the main purpose of clarifying the origin and nature of the hairs that cover the seeds and aiding future taxonomical and ecological studies of the group. The fruit is an ellipsoid loculicide capsule and presents the exocarp formed by 7-10 cells layers, with very thick walls and evident simple pits. A great number of mucilage secretory cavities and ramified vascular bundles, accompanied by fibers, occur in the parenchymatic mesocarp. The endocarp derives from the ventral epidermis of the ovary wall, whose cells undergo a gradual elongation, become lignified, and constitute the trichomes which cover the mature seeds. The fruit aperture occurs by means of a suture evident in the ovarian wall in the middle region of the carpel leaf. Anatropous and bitegmic ovules, provided by a hypostase, give rise to campilotropous and bitegmic seeds. The testa is uniseriate, the exotegmen is completely formed by macrosclereids, and mucilage secretory cavities occur in the mesotegmen. The endotegmen, which is differentiated in the endothelium, is crushed in the mature seed. The plicate embryo, which occupies practically the entire seminal cavity, is found between endosperm layers, both being rich in lipids.

Female gametophyte development in Adesmia latifolia (Spreng.) Vog. (Leguminosae - Papilionoideae)

The female gametophyte has a monosporic origin and a Polygonum type development. The female gametophyte growth consumes a large part of the neighboring nucellar cells and, in the micropylar region, part of the nucellar epidermis and internal integument. The mature gametophyte is composed of only four cells due to the ephemeral characteristic of the antipodals. The synergids are pear-shaped cells with the formation of filiform apparatus. Their nuclei lie in the micropylar region and large vacuoles in the chalazal region, while the egg cell presents an opposite polarization. The central cell accumulates starch grains and the two polar nuclei approach the egg. Occasional development of two gametophytes was recorded. The closest to the micropyle develops fully, while the chalazal one remained in the tetranucleated stage. The embryological characters of A. latifolia are compared with those of other taxa within the Leguminosae, and the reproductive importance of multiple gametophyte formation for this species was discussed.

Development of fetal nicotine and muscarinic receptors in utero

The role of acetylcholine in the central and peripheral nervous systems is well established in adults. Cholinergic modulation of vascular functions and body fluid balance has been extensively studied. In the embryo-fetus, cholinergic receptors are widespread in the peripheral and central systems, including smooth muscle and the epithelial lining of the cardiovascular, digestive, and urinary systems, as well as in the brain. Fetal nicotine and muscarinic receptors develop in a pattern (e.g., amount and distribution) related to gestational periods. Cholinergic mechanisms have been found to be relatively intact and functional in the control of vascular homeostasis during fetal life in utero at least during the last third of gestation. This review focuses on the development of fetal nicotine and muscarinic receptors, and provides information indicating that central cholinergic systems are well developed in the control of fetal blood pressure and body fluid balance before birth. Therefore, the development of cholinergic systems in utero plays an important role in fetal vascular regulation, gastrointestinal motility, and urinary control.