Transfer of the monospecific genus Nienburgella (Delesseriaceae, Rhodophyta) to Phycodrys, based on morphological and molecular evidence

The genus Phycodrys is characterized by having a Phycodrys-type apical organization, a well-developed central midrib with paired lateral veins, monostromatic areas between the veins, four-celled carpogonial branches with two groups of sterile cells, and a cystocarp with a large fusion cell and short-catenated carposporangia. In contrast, the monospecific genus Nienburgella has a faint midrib, a mostly polystromatic blade without lateral veins, bilaterally isometric second-order cell row length, and Phycodrys-like apical growth and cystocarp. Nothing is known about Nienburgella’s procarp. We collected several specimens of Nienburgella angusta from the East Sea of South Korea and noticed that they resemble Phycodrys radicosa. We compared these two species using morphological and molecular phylogenetic analyses. Our results revealed that both species are closely related to one another than to other taxa in the tribe Phycodryeae, and that Nienburgella angusta procarp developmental pattern is the same as the one observed in Phycodrys rubens, the generitype species of Phycodrys. Thallus structure (mono- or polystromatic) was species-delimiting but not genus-delimiting. Bilateral second-order cell row isometry occurs in other Phycodrys species, including the type species. Therefore, we propose transferring the species Nienburgella angusta as well as the monospecific genus Nienburgella to Phycodrys.

Choroidal readaptation to gravity in rats after spaceflight and head-down tilt

Davet, Julien, Benoit Clavel, Lucien Datas, Laurence Mani-Ponset, Daniel Maurel, Serge Herbuté, Michel Viso, William Hinds, Joellen Jarvi, and Jacqueline Gabrion.Choroidal readaptation to gravity in rats after spaceflight and head-down tilt. J. Appl. Physiol.84(1): 19–29, 1998.—To determine when choroidal structures were restored after readaptation to Earth gravity or orthostatic position, fine structure and protein distribution were studied in rat choroid plexus dissected either 6 h [Space Life Sciences-2 (SLS-2) experiments] or 2 days [National Institutes of Health-Rodent 1 (NIH-R1) experiments] after a spaceflight, or 6 h after head-down tilt (HDT) experiments. Apical alterations were noted in choroidal cells from SLS-2 and HDT animals, confirming that weightlessness impaired choroidal structures and functions. However, the presence of small apical microvilli and kinocilia and the absence of vesicle accumulations showed that the apical organization began to be restored rapidly after landing. Very enlarged apical microvilli appeared after 2 days on Earth, suggesting increased choroidal activity. However, as distributions of ezrin and carbonic anhydrase II remained altered in both flight and suspended animals after readaptation to Earth gravity, it was concluded that choroidal structures and functions were not completely restored, even after 2 days in Earth’s gravity.

Nitrogen Form and Solution pH Effects on Root Anatomy of Cranberry

Root sections of cranberry (Vaccinium macrocarpon Ait. cv. Searles) were microscopically examined to document the typical anatomy of cranberry roots and changes in root anatomy in response to N-form and solution pH. Cranberry cuttings were rooted, then established in hydroponic conditions with three N and two pH regimes. The three N regimes with equal N levels were 1) NH4-N alone, 2) NH4/NO3-N in combination, or 3) NO3-N alone. pH was maintained at 4.5 or 6.5. Root apical regions were examined using phase contrast, bright field, and epifluorescence microscopy. The cranberry root tip develops with a closed apical organization with the tetrarchal vascular cylinder, cortex, and root cap traceable to independent meristem cell layers. The most obvious treatment difference was an accumulation of unidentified “granules” in the subepidermal layer, readily visible with epifluorescence microscopy with NO3-N alone. Roots produced at pH 4.5 branched less than those at 6.5 and had more “quiescent” root initials; at pH 6.5, these developed more frequently into branch roots.