Lateral Strands Research Articles

Flexible Aliphatic Diammonioacetates as Zwitterionic Ligands in UO22+ Complexes: Diverse Topologies and Interpenetrated Structures.

N,N,N',N'-Tetramethylethane-1,2-diammonioacetate (L1) and N,N,N',N'-tetramethylpropane-1,3-diammonioacetate (L2) are two flexible zwitterionic dicarboxylates which have been used as ligands for the uranyl ion, 12 complexes having been obtained from their coupling to diverse anions, mostly anionic polycarboxylates, or oxo, hydroxo and chlorido donors. The protonated zwitterion is a simple counterion in [H2L1][UO2(2,6-pydc)2] (1), where 2,6-pydc2- is 2,6-pyridinedicarboxylate, but it is deprotonated and coordinated in all the other complexes. [(UO2)2(L2)(2,4-pydcH)4] (2), where 2,4-pydc2- is 2,4-pyridinedicarboxylate, is a discrete, binuclear complex due to the terminal nature of the partially deprotonated anionic ligands. [(UO2)2(L1)(ipht)2]·4H2O (3) and [(UO2)2(L1)(pda)2] (4), where ipht2- and pda2- are isophthalate and 1,4-phenylenediacetate, are monoperiodic coordination polymers in which central L1 bridges connect two lateral strands. Oxalate anions (ox2-) generated in situ give [(UO2)2(L1)(ox)2] (5) a diperiodic network with the hcb topology. [(UO2)2(L2)(ipht)2]·H2O (6) differs from 3 in being a diperiodic network with the V2O5 topological type. [(UO2)2(L1)(2,5-pydc)2]·4H2O (7), where 2,5-pydc2- is 2,5-pyridinedicarboxylate, is a hcb network with a square-wave profile, while [(UO2)2(L1)(dnhpa)2] (8), where dnhpa2- is 3,5-dinitro-2-hydroxyphenoxyacetate, formed in situ from 1,2-phenylenedioxydiacetic acid, has the same topology but a strongly corrugated shape leading to interdigitation of layers. (2R,3R,4S,5S)-Tetrahydrofurantetracarboxylic acid (thftcH4) is only partially deprotonated in [(UO2)3(L1)(thftcH)2(H2O)] (9), which crystallizes as a diperiodic polymer with the fes topology. [(UO2)2Cl2(L1)3][(UO2Cl3)2(L1)] (10) is an ionic compound in which discrete, binuclear anions cross the cells of the cationic hcb network. 2,5-Thiophenediacetate (tdc2-) is peculiar in promoting self-sorting of the ligands in the ionic complex [(UO2)5(L1)7(tdc)(H2O)][(UO2)2(tdc)3]4·CH3CN·12H2O (11), which is the first example of heterointerpenetration in uranyl chemistry, involving a triperiodic, cationic framework and diperiodic, anionic hcb networks. Finally, [(UO2)7(O)3(OH)4.3Cl2.7(L2)2]Cl·7H2O (12) crystallizes as a 2-fold interpenetrated, triperiodic framework in which chlorouranate undulating monoperiodic subunits are bridged by the L2 ligands. Complexes 1, 2, 3, and 7 are emissive with photoluminescence quantum yields in the range of 8-24%, and their solid-state emission spectra show the usual dependence on number and nature of donor atoms.

Monitoring the apical growth characteristics of hairy roots using non-invasive laser speckle contrast imaging.

Hairy roots are used to produce plant agents and additives. Due to their heterogeneous structure and growth characteristics, it is difficult to determine growth‐related parameters continuously and in real time. Laser speckle contrast analysis is widely used as a non‐destructive measurement technique in material testing or in medical technology. This type of analysis is based on the principle that moving objects or particles cause fluctuations in stochastic interference patterns known as speckle patterns. They are formed by the random backscattering of coherent laser light on an optically rough surface. A Laser Speckle Imager, which is well established for speckle studies of hemodynamics, was used for the first time for non‐invasive speckle measurements on hairy roots to study dynamic behavior in plant tissue. Based on speckle contrast, a specific flux value was defined to map the dynamic changes in the investigated tissue. Using this method, we were able to predict the formation of lateral strands and to identify the growth zone in the apical root region, as well as dividing it into functional regions. This makes it possible to monitor physiological processes in the apical growth zone in vivo and in real time without labeling the target structures.

Arabidopsis vascular complexity and connectivity controls PIN-FORMED1 dynamics and lateral vein patterning during embryogenesis.

Arabidopsis VASCULATURE COMPLEXITY AND CONNECTIVITY (VCC) is a plant-specific transmembrane protein that controls the development of veins in cotyledons. Here, we show that the expression and localization of the auxin efflux carrier PIN-FORMED1 (PIN1) is altered in vcc developing cotyledons and that overexpression of PIN1-GFP partially rescues vascular defects of vcc in a dosage-dependent manner. Genetic analyses suggest that VCC and PINOID (PID), a kinase that regulates PIN1 polarity, are both required for PIN1-mediated control of vasculature development. VCC expression is upregulated by auxin, likely as part of a positive feedback loop for the progression of vascular development. VCC and PIN1 localized to the plasma membrane in pre-procambial cells but were actively redirected to vacuoles in procambial cells for degradation. In the vcc mutant, PIN1 failed to properly polarize in pre-procambial cells during the formation of basal strands, and instead, it was prematurely degraded in vacuoles. VCC plays a role in the localization and stability of PIN1, which is crucial for the transition of pre-procambial cells into procambial cells that are involved in the formation of basal lateral strands in embryonic cotyledons.

A new species of Ashicaulis (Osmundaceae) from the Mesozoic of China: A close relative of living Osmunda claystoniana L.

A new species, Ashicaulis claytoniites, is established based on two specimens collected from Middle Jurassic sediments near Duanmugou, Changgao Village, Beipiao County, west Liaoning Province of China. The specimens represent stems surrounded by a mantle of stipular petiole bases and adventitious roots. The stems, 6–8 mm in diameter, consist of an ectophloic dictyoxylic stele and a two-layered cortex containing 31–37 leaf traces. When departing from the stele, the leaf traces are a flattened C-shaped, with an endarch protoxylem which bifurcates at the base of petiole. The sclerenchyma ring is heterogeneous with an arch of stipular petiole base at the base that are divided into two lateral strands at the top. A big mass heterogeneous sclerenchyma is present in the stipular wing. In the ectophloic dictyoxylic stele and arrangement of sclerenchyma of the petiole base, Ashicaulis claytoniites shares smiliarities with Osmunda claytoniana L. of Osmunda subg. Osmunda, but not with other subgenera of Osmunda subg. Plenasium, Osmundastrum, the genera Todea, and Leptopteris in the extant Osmundaceae. According to the similarities of these features, a distinct relationship is suggested between Ashicaulis claytoniites and Osmunda claytoniana. The new species could be a close Mesozoic relative of O. claytoniana. This new species shows the similar arrangement of the sclerenchyma of the petiole base with the Mesozoic species, Millerocaulis preosmunda, suggesting that the morphogenera Millerocaulis and Ashicaulis are closely related, and the new species may be a transitional form between the Mesozoic M. preosmunda and Osmunda claytoniana of extant subgenus Osmunda.

A New Species of Millerocaulis (Osmundaceae) from the Middle Jurassic of China and Its Implication for Evolution of Osmunda

A new species, Millerocaulis preosmunda, is established based on specimens collected from the Lanqi Formation (Middle Jurassic) near Changgao, Liaoning Province, China, and provides evidence for tracing the evolution of living Osmunda subg. Osmunda. The specimens represent two stems surrounded by a mantle of stipular petiole bases and adventitious roots. The stems, 10–13 mm in diameter, consist of siphonostele and a two‐layered cortex containing 32–35 leaf traces. When departing from the stele, the leaf traces are a flattened C shape, with an endarch protoxylem that bifurcates at the base of the petiole. Sclerenchyma rings are heterogeneous and change from an abaxial band at the base of stipular petiole bases to two lateral strands at the top. A heterogeneous sclerenchyma mass is present in each stipular wing at the midpoint of the petiole base. Millerocaulis preosmunda shows similarity in the arrangement of sclerenchyma of the petiole base to Osmunda subg. Osmunda but not to other Osmunda subg. Plenasium and Osmundastrum or to genera Todea and Leptopteris in extant Osmundaceae. The similar structures in the petiole base indicate that the new species could be a close relative or direct precursor of Osmunda subg. Osmunda.

Floral vasculature in Alpinia hainanensis in relation to the nature of the labellum in gingers

Observations presented here on floral vasculature in Alpinia hainanensis indicate that the labellum incorporates elements of five androecial members rather than two or three, as suggested by previous authors for Zngiberaceae flowers. The pedicel contains an outer ring and a central region of vascular bundles. Three carpellary dorsal bundles (CDs) and three alternatively arranged parietal bundles (PBs) separate from the central region successively. The remaining bundles of the central region run upwards and become the placental bundles to supply ovules. The placental bundles terminate between the top of the locular region and the base of the prolongation. The three PBs divides into about five strands respectively. Of which the outer strand enters into the petal being its midrib and the remaining strands move into the stamen adaxially being the vasculature of the functional stamen and the labellum abaxially being the lateral strands of the labellum. The three CDs divide into about five traces, of which the outer strand becomes the midrib of each sepal and the inner strand runs into the style. The remaining traces re‐unite, re‐divide again in the course up and the two adaxial sets of carpellary dorsals finally enter into the labellum being the marginal traces of it while the abaxial single strand enters into the labellum being its midrib. The two antero‐lateral glands receive small traces without lignified tube elements from the vascular plexus, which fonn in prolongation from both PBs and CDs and a few small strands in the ovary wall. There are no subulate appendages differentiated in the flower of Alpinia hainanensis. Hereby, the median of the sepals, both the marginal portions and the median of labellum, and the style have the same origin in vasculature from the CDs and so do the stamen, the lateral portions of labellum and the median of the petals from PBs. The labellum is supposed to represent three members of the outer androecial whorl by its two marginal portions and the median and two members of the inner whorl by its two lateral parts except the median.

Morpho-anatomical characters of the achene in certain species of sub-family Rosoideae (Rosaceae), a comparative study

The morpho-anatomical characters of 18 species belonging to six genera of sub-family Rosoideae wereinvestigated. The anatomical characters of both the pericarp and testa were found to be impracticable for speciesdelimitation since they are consistent at the generic level. The same reason rendered the character evaluationinvaluable within the species of the same genus. Of the morphological characters the mode of the achenevasculature as well as its ramification varied in the different taxa. The basic number of the achene supply is onemedian and two lateral strands. The behaviour of the latter, whether distinct or fused, as well as the ramification ,or not, of a part or the whole of the vascular skeleton led to the suggestion of a key-like layout which shows thepathway of these character states as being primitive vs advanced.

Chronic inflammation induces alterations in the zonula occludens (ZO) and lateral junctional strands of mucosal epithelial cells in rabbit ileum

Chronic inflammation induces alterations in the zonula occludens (ZO) and lateral junctional strands of mucosal epithelial cells in rabbit ileum

An atomic force microscopical study of the synaptonemal complex

The chromosomal structure which is specific for meiosis, the synaptonemal complex (SC), plays a major role in chromosome pairing and the recombination of genetic material. The SC was studied using atomic force microscopy (AFM). The results of this study confirm the results of light and electron microscopic studies of the SC. The SC primarily shows a tripartite structure, composed of two lateral elements and a central element connected to each other by transversal elements. The lateral element of the SC shows a lateral subdivision in secondary lateral strands. In addition, a new repetitive transversal subdivision of the lateral elements was observed. Furthermore, the SC substructure which is probably responsible for recombination, the recombination nodule, could be observed ouside the confines of the SC.

Anatomically preserved Dicroidium foliage from the central transantarctic mountains

The first anatomically preserved species of Dicroidium, D. fremouwensis Piggs sp. nov. is described from the Triassic of the central Transantarctic Mountains, Antarctica. Dicroidium fremouwensis has pinnules that ranges from entire-margined to highly lobed morphologies. Entire-margined pinnules occur basally and pinnules become progressively more dissected at more distal levels of the frond. Dicroidium fremouwensis is most similar to the compression-impression forms D. dubium var. dubium (Feistmantel) Retallack and D. dubium var. tasmaniense (Anderson et Anderson) Retallack. Fronds also bear some resemblance to D. sp cf. D. feistmantelii sensu Lele, D. dubium (Feistmantel) Gothan and D. feistmantelii (Johnston) Gothan. Distal to the frond bifurcation, pinna rachides have a dorsiventral vascular anatomy composed of an abaxial ring of six to eight bundles and an adaxial linear group of five to eight bundles. Bundles of the adaxial line produce lateral strands that vascularize laminar pinnules, while the abaxial bundles remain in a ring that diminishes to three bundles distally. Pinnules have odontopterid venation, differentiated mesophyll, resinous cells and transfusin tracheids. The vascular organization and other anatomical features of D. fremouwensis are similar to those of the fronds of some extant cycads. This information provides a new level of resolution in our knowledge of Dicroidium and documents how permineralized fossils promise to refine our understanding of complex Mesozoic gymnosperms.

Biological, chemical, immunological and staining properties of bacteria isolated from tissues of leprosy patients

Two kinds of microorganisms are found in tissue of leprosy patients: Mycobacterium leprae (ML) and leprosy derived corynebacteria (LDC). ML from untreated patients has an alcohol-acid-fastness, which is lost upon treatment with antibiotics and immune response (tuberculoid leprosy). Vulnerable ML thus produced can be reversibly de-stained by organic solvent: in tissue sections from tuberculoid and treated patients, more bacteria are, thus, revealed by the Wade-Fite than by the Ziehl-Neelsen procedure. Organisms of genera Corynebacterium, Mycobacterium and Nocardia (CMN group), have DNA with %GC contents of 50-70, 69-72, and 68-70 respectively. GC values of DNA from ML and LDC are close to 56%. DNA from different LDC strains display high homology among them and low homology with reference corynebacteria. CMN cell wall consists of interconnected peptidoglycan and polysaccharide-mycolate complex. Peptidoglycan of LDC (and known CMN) has the polysaccharide backbone linked to a tetrapeptide of L-Ala, D-Glu, m-DAP (meso-diaminopimelate), D-Ala. In ML, L-Ala is replaced by glycine. Mycobacterial wall polysaccharides (that of ML is unknown) are branched arabinogalactans with end arabinoses linked to C70 to C90 mycolates. LDC peripheral polysaccharides are arabinogalactomannans with arabinose and mannose lateral strands. Mycolic acids of LDC are of corynomycolic type (C32, C34 and C36 with 1-4 double bonds) and those of ML are of mycobacterial type. Components of CMN wall and cytoplasm are immunologically active as antigens (polysaccharides, proteins), haptens (lipids) and adjuvants (peptidoglycans). Strong intrageneric and weak intergenera crossreactions are observed among CMN bacteria: LDC preparations, however, crossreact strongly with ML and mycobacteria, and weakly with reference corynebacteria. LDC in leprosy tissues can, thus, be revealed as well by fluorescent anti-LDC antisera as by anti-ML antisera. The main crossreacting component is antigen M1 of LDC, which corresponds to antigens Ag 7 of ML and Ag60 of BCG, the active components of lepromin and tuberculin (known reagents for cutaneous tests). Antigen M1 has a polysaccharide moiety crossreacting with the wall polysaccharide of LDC.(ABSTRACT TRUNCATED AT 400 WORDS)

Initiation of primary vascular elements in the stamens and carpel of Triticum aestivum L.

The primary vascular elements originate in the procambia of the single carpel and three stamens of the floret independently and in isolation from the vascular system of the spikelet. The initiation of protophloem elements is earlier in the stamens than in the carpel. The median strand of the carpel differentiates before the two lateral strands. The protoxylem elements are initiated after the protophloem elements are welt differentiated. The differentiation of both protophloem and protoxylem elements is bidirectional in the stamens and in the three strands of the carpel, whereas their differentiation is acropetal in the funicular strand of the carpel.

Determination and differentiation of the procambium in the shoot apex ofClematis vitalba L. (Ranunculaceae)

The development of the shoot apex is studied in regard to relationships between morphogenesis and histogenesis. Differentiation of procambium starts only some distance from the shoot apex at the basis of leaf initials and continues from the node into leaf and axis. Lateral strands appear parallel with the first ternation in the leaf. The development of procambium strands is correlated with the differentiation in the axis and there seems to be a mutual stimulation between leaf initial and procambium.

Comparative DNA renaturation kinetics in amphibians.

Amphibian haploid genome sizes vary from 9 x 10(8) to 8 x 10(10) nucleotide pairs. The rate of reassociation of DNA from amphibians of different genome sizes has been employed to eliminate one of the theoretical models of chromosome structure. Scaphiopus couchi, Bufo marinus, and Rana clamitans, whose haploid genome sizes are in the ratio 2:7:10, all contain sequences of DNA represented once in the haploid genome. This indicates that their chromosomes are not composed of identical lateral strands (polynemy). The relative frequencies of repetition of DNA sequences are different for the various species of amphibians. The observed frequencies of repetitive DNA sequences in amphibians do not show the relationships expected if amphibians form a polyneme series.

The skin and hair of the Southern Elephant Seal Mirounga leonina (L.) III. morphology of the adult integument

The histological structure and certain histochemical features of the skin, hair follicles, and associated glands have been studied in 57 male and 49 female elephant seals. The epidermis comprises only three layers, stratum germinativum, stratum spinosum, and stratum corneum. The absence of granular and clear layers leads to a parakeratotic condition of the horny layer which is made up of large cornified sheets joined to lateral strands of the pelage hairs. Although pigment abounds in the interfollicular epidermis, it does not extend into the external root sheath cells of the hair follicles. There are no arrector pili muscles attached to the pelage hair follicles which are simple, unbranched, and contain only one fully developed lanceolate hair. Hairs are firmly anchored in their follicles by means of lateral filaments insinuated between external root sheath cells. A single, small, apocrine-type sweat gland opens into the hair canal below the common duct of the large, bilobed, sebaceous gland on the ental side of the follicle. The lipid-rich sebum is secreted within the lamellae of the stratum corneum and its function appears to be the maintenance of the outer horny layers in a pliable and perhaps water-resistant condition. The walls of the sebaceous duct are replete with glycogen. The dermis comprises a network of collagenous fibres and a decreasing number of elastic fibres in aging seals, as well as histiocytes and dermal fat cells. Problems of thermoregulation arising from loss of hair in seals exemplified by M. leonina and compensatory features apparent in the morphology of the skin and hair are discussed.

Morphology of the Gynobase in Mertensia

The conformation of the ring-like disc or gynobase surrounding the gynoecium varies greatly among the genera of Boraginaceae. The morphology of the gynobase ha's been taken for granted by most systematists, and has been used descriptively in connection with description of nutlet attachment. No morphological or evolutionary significance has been attached to the gynobase. In other families, anatomical and morphological studies have demonstrated that many discs, nuptial nectaries, and floral squamellae may be interpreted in terms of the other appendages of the flower. For example, it is believed that the sheathing disc about the carpel in many Leguminosae represents an abortive set of stamens.1 Structures adjacent to the gynoecium which have been observed in many Apocynaceae are interpreted as carpellodes.2 The heteromorphic nature of the gynobase of Mertensia is apparent on gross examination (Figs. 15, 16). The four unequal lobes of the gynobase alternate with the four nutlets of the pistil. Opposed to the carpels are two small obtusely triangular pointed lobes. Alternated with the carpels are the two large lobes which equal or surpass the nutlets in size. For a better understanding of the morphology of the gynobase it is necessary to describe briefly the anatomy of the flower in Mertensia. The vascular anatomy of the flower is not especially complicated in Mertensia. In most respects the description given here applies to other members of the Boraginaceae which I have examined (Figs. 1-13). The pedicel contains a circle of ten strands, alternately large and small (Fig. 1). The five smaller traces swing outward and upward to supply the sepals (Fig. 4). These strands split radially into 3 parts after they leave the stele. Lateral strands of adjacent calyx lobes do not fuse. The sepal gaps close, and then the petal and stamen traces begin to depart (Fig. 5). Each stamen receives one trace. There are five petal traces, and these split radially into three members after leaving the stele. The petal and stamien trace gaps close and the stele becomes provascular except for the strands which are to supply the carpels (Fig. 7). Each carpel is provided with three traces. The two ventrals of each carpel swing inward and upward toward the center of the flower, each eventually ascending through the placenta into the funiculus (Figs. 10-12). The dorsal bundle pursues a devious upward course which leads into the style. The median lateral bundles seen in the nutlet walls apparently arise from the placental bundles, curve upward into the wall of the nutlet and then gradually die out.

The Anatomy of the Genus Salicornia.

The Anatomy of the Genus Salicornia.