scholarly journals A revision of Chara sect. Protochara, comb. et stat. nov. (Characeae: Charophyceae)

2014 ◽  
Vol 27 (1) ◽  
pp. 23 ◽  
Author(s):  
Michelle T. Casanova ◽  
Kenneth G. Karol
Keyword(s):  
Accessory Cells ◽  
Chara Australis

A revision of a group of ecorticate species of Chara is presented, on the basis of fresh, pressed and spirit-preserved material. The following seven species are recognised, characterised by a very simple morphology, with few or inconspicuous accessory cells (cortication, stipulodes, bract cells, bracteoles) and large gametangia: Chara australis R.Br., C. lucida (A.Braun) Casanova & Karol comb et. stat. nov., C. porteri Casanova, sp. nov., C. protocharoides Casanova & Karol, nom. nov. (=Protochara australis Womersley & Ophel) and C. stuartiana (Kütz.) Casanova & Karol comb. et. stat. nov. from Australia, and C. corallina Klein ex Willd. and C. wallichii A.Braun from Asia. A new section, Chara subg. Charopsis sect. Protochara (Womersley & Ophel) Casanova & Karol, comb. et stat. nov., is erected to accommodate these taxa, formerly placed in sect. Charopsis.

scholarly journals Direct Binding of Human NK Cell Natural Cytotoxicity Receptor NKp44 to the Surfaces of Mycobacteria and Other Bacteria

2008 ◽  
Vol 76 (4) ◽  
pp. 1719-1727 ◽  
Author(s):  
Semih Esin ◽  
Giovanna Batoni ◽  
Claudio Counoupas ◽  
Annarita Stringaro ◽  
Franca Lisa Brancatisano ◽  
...  
Keyword(s):  
Nk Cells ◽  
Nk Cell ◽  
Cell Subset ◽  
Surface Expression ◽  
Binding Assays ◽  
Igg Antibody ◽  
Direct Stimulation ◽  
Activating Receptors ◽  
Accessory Cells

ABSTRACT Our previous studies demonstrated that Mycobacterium bovis bacillus Calmette-Guérin (BCG) can directly interact with human NK cells and induce the proliferation, gamma interferon production, and cytotoxic activity of such cells without the need for accessory cells. Thus, the aim of the present study was to identify the putative receptor(s) responsible for the recognition of BCG by human NK cells and potentially involved in the activation of NK cells. To this end, we first investigated the surface expression of three NK cell-activating receptors belonging to the natural cytoxicity receptor (NCR) family on highly purified human NK cells upon in vitro direct stimulation with BCG. An induction of the surface expression of NKp44, but not of NKp30 or NKp46, was observed after 3 and 4 days of in vitro stimulation with live BCG. The NKp44 induction involved mainly a particular NK cell subset expressing the CD56 marker at high density, CD56bright. In order to establish whether NKp44 could directly bind to BCG, whole BCG cells were stained with soluble forms of the three NCRs chimeric for the human immunoglobulin G (IgG) Fc fragment (NKp30-Fc, NKp44-Fc, NKp46-Fc), followed by incubation with a phycoerythrin (PE)-conjugated goat anti-human IgG antibody. Analysis by flow cytometry of the complexes revealed a higher PE fluorescence intensity for BCG incubated with NKp44-Fc than for BCG incubated with NKp30-Fc, NKp46-Fc, or negative controls. The binding of NKp44-Fc to the BCG surface was confirmed with immunogold labeling using transmission electron microscopy, suggesting the presence of a putative ligand(s) for human NKp44 on the BCG cell wall. Similar binding assays performed on a number of gram-positive and gram-negative bacteria revealed a pattern of NKp44-Fc binding restricted to members of the genus Mycobacterium, to the mycobacterium-related species Nocardia farcinica, and to Pseudomonas aeruginosa. Altogether, the results obtained indicate, for the first time, that at least one member of the NCR family (NKp44) may be involved in the direct recognition of bacterial pathogens by human NK cells.

scholarly journals The molecular identity of the characean OH− transporter: a candidate related to the SLC4 family of animal pH regulators

PROTOPLASMA ◽  
2021 ◽  
Author(s):  
Bianca N. Quade ◽  
Mark D. Parker ◽  
Marion C. Hoepflinger ◽  
Shaunna Phipps ◽  
Mary A. Bisson ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Membrane Conductance ◽  
Resting Potential ◽  
Large Scatter ◽  
Intrinsic Variability ◽  
Molecular Identity ◽  
Ph Banding ◽  
Chara Australis ◽  
Ph Increase ◽  
External Ph

AbstractCharaceae are closely related to the ancient algal ancestors of all land plants. The long characean cells display a pH banding pattern to facilitate inorganic carbon import in the acid zones for photosynthetic efficiency. The excess OH−, generated in the cytoplasm after CO2 is taken into the chloroplasts, is disposed of in the alkaline band. To identify the transporter responsible, we searched the Chara australis transcriptome for homologues of mouse Slc4a11, which functions as OH−/H+ transporter. We found a single Slc4-like sequence CL5060.2 (named CaSLOT). When CaSLOT was expressed in Xenopus oocytes, an increase in membrane conductance and hyperpolarization of resting potential difference (PD) was observed with external pH increase to 9.5. These features recall the behavior of Slc4a11 in oocytes and are consistent with the action of a pH-dependent OH−/H+ conductance. The large scatter in the data might reflect intrinsic variability of CaSLOT transporter activation, inefficient expression in the oocyte due to evolutionary distance between ancient algae and frogs, or absence of putative activating factor present in Chara cytoplasm. CaSLOT homologues were found in chlorophyte and charophyte algae, but surprisingly not in related charophytes Zygnematophyceae or Coleochaetophyceae.

scholarly journals Definition of conditions that enable antigen-specific activation of the majority of isolated trinitrophenol-binding B cells.

1982 ◽  
Vol 156 (6) ◽  
pp. 1635-1649 ◽  
Author(s):  
J C Cambier ◽  
J G Monroe ◽  
M J Neale
Keyword(s):  
Cell Cycle ◽  
T Cell ◽  
Interleukin 1 ◽  
Isolated Cells ◽  
Cellular Events ◽  
Accessory Cells ◽  
B Cell Growth Factor ◽  
Human Gamma Globulin ◽  
Definition Of ◽  
T Cell Help

In an effort to further elucidate the early cellular events in generation of antibody responses, we have determined the requirements for antigen-specific initiation of the G0 to G1 transition by isolated trinitrophenol (TNP) -binding B lymphocytes. TNP-binding cells were isolated from normal B6D2F1 splenocyte populations using hapten affinity fractionation on disulfide-bonded TNP-gelatin-coated plates. Populations prepared in this way are greater than or equal to 96% immunoglobulin positive and 70-95% antigen binding. Isolated cells were cultured for 48 h in the presence of a variety of TNP conjugates including TNP-Brucella abortus (Ba), TNP-Ficoll, TNP-sheep erythrocytes (SRBC), TNP-human gamma globulin (HGG), or TNP-ovalbumin (OVA) before being harvested and subjected to acridine orange cell cycle analysis. As many as 80% of cells were in cycle by 48 h in response to TNP-Ba, a thymus-independent (TI1 antigen. A smaller proportion (congruent to 40%) were in cycle in response to TNP-Ficoll, a TI2 antigen. Significant activation was not detected in cultures challenged with the thymus-dependent immunogens TNP-SRBC, TNP-HGG, and TNP-OVA. Addition of interleukin 1 (IL-1), IL-2, B cell growth factor, and/or T cell-replacing factor to cultures did not facilitate responses to these immunogens, suggesting a requirement for antigen-specific T cell help for entry into cell cycle induced by thymus dependent antigens. Activation by TNP-Ba was antigen specific and independent of accessory cells, occurring with equal efficiency in bulk and single-cell cultures. Activation by TNP-Ba was inhibitable by anti-Fab and anti-mu antibodies, but not by anti-delta antibodies. Results indicate that activation of TNP-binding cells to enter cell cycle by TNP-Ba is independent of accessory cells and requires interaction of antigen with cell surface IgM. Exposure to thymus-dependent TNP-immunogens plus nonspecific helper factors is insufficient to cause entry of TNP-binding cells into cycle.

scholarly journals Transcriptional signature of accessory cells in the lateral line, using the Tnk1bp1:EGFP transgenic zebrafish line

2012 ◽  
Vol 12 (1) ◽  
pp. 6 ◽  
Author(s):  
Martine Behra ◽  
Viviana E Gallardo ◽  
John Bradsher ◽  
Aranza Torrado ◽  
Abdel Elkahloun ◽  
...  
Keyword(s):  
Lateral Line ◽  
Transgenic Zebrafish ◽  
Transcriptional Signature ◽  
Accessory Cells

scholarly journals T cell regulation of b cell activation. Cloned Lyt-1+2-T suppressor cells inhibit the major histocompatibility complex-restricted interaction of T helper cells with B cells and/or accessory cells.

1983 ◽  
Vol 158 (4) ◽  
pp. 1178-1190 ◽  
Author(s):  
Y Asano ◽  
R J Hodes
Keyword(s):  
Major Histocompatibility Complex ◽  
B Cells ◽  
Cell Activation ◽  
Suppressor Cells ◽  
Major Histocompatibility ◽  
T Helper ◽  
Th Cells ◽  
Effector Cells ◽  
Histocompatibility Complex ◽  
Accessory Cells

The present studies have identified cloned Lyt-1+2- T suppressor (Ts) cells that are both antigen specific and major histocompatibility complex (MHC) restricted in their activation requirements and that function to regulate the MHC-restricted activation of B cells by T helper (Th) cells. ParentA-restricted Ts clones suppressed, in antigen-specific fashion, the responses generated by (A X B)F1 Th cells cooperating with parentA (B plus accessory) cells, but did not suppress responses by the same (A X B)F1 Th cell population cooperating with parentB (B plus accessory) cells. Moreover, responses of (A X B)F1 leads to parentA Th cells and (A X B)F1 (B plus accessory) cells were suppressed by parentA-restricted Ts clones but not by parentB-restricted Ts clones. Thus, these findings suggest that the cloned Ts cells that have been characterized here function by specifically inhibiting the MHC-restricted interaction between Th cells and B and/or accessory cells. It was further demonstrated in experiments using cloned Th and Ts populations that these Lyt-1+2-Ts cells act not simply as inducers of suppressor but rather function in a restricted fashion as effector cells in the suppressor pathway.

Accessory cells and macrophages in the histopathology of SIVsm-infected cynomolgus monkeys

1993 ◽  
Vol 144 ◽  
pp. 81-92 ◽  
Author(s):  
E. Kaaya ◽  
S.-L. Li ◽  
H. Feichtinger ◽  
I. Stahmer ◽  
P. Putkonen ◽  
...  
Keyword(s):  
Cynomolgus Monkeys ◽  
Accessory Cells

6 Murine T cell subsets and interleukins: Relationships between cytotoxic T cells, helper T cells and accessory cells

1982 ◽  
Vol 11 (3) ◽  
pp. 607-630
Author(s):  
Hermann Wagner ◽  
Martin Kronke ◽  
Werner Solbach ◽  
Peter Scheurich ◽  
Martin Röllinghoff ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cytotoxic T Cells ◽  
T Cell Subsets ◽  
Helper T Cells ◽  
Accessory Cells
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