Different membrane anchors of Fc gamma RIII (CD16) on K/NK-lymphocytes and neutrophils. Protein- vs lipid-anchor

Fc gamma RIII (CD16), the type three receptor for the Fc portion of IgG, is expressed on neutrophils, killer (K)/NK lymphocytes and macrophages. K/NK lymphocyte Fc gamma RIII, which plays a role in antibody-dependent cellular cytotoxicity, is an efficient signal transducing molecule, whereas neutrophil Fc gamma RIII, which plays a role in immune-complex clearance, seems less efficient in signal transduction. Neutrophil Fc gamma RIII has been reported to be a glycan-phosphatidylinositol-anchored membrane protein. Our studies suggest that K/NK lymphocyte Fc gamma RIII is protein-anchored rather than glycan-phosphatidylinositol-anchored. That is, K/NK lymphocyte Fc gamma RIII was resistant to phosphatidylinositol-specific phospholipase C and surface expression of Fc gamma RIII was not affected on K/NK lymphocytes from patients with paroxysmal nocturnal hemoglobinuria, a disorder of hemopoietic stem cells resulting in deficient expression of glycan-phosphatidylinositol-anchored proteins. Different membrane anchoring mechanisms of the Fc gamma RIII may account for different consequences of the ligand binding to two cell types.     

Effect of UV-B (290–320 nm) irradiation on growth and metabolism of cucumber cotyledons

Cucumber ( Cucumis sativus L. cv. Natsusairaku 3) seedlings were grown in a growth cabinet under UV-B (290–320 nm) irradiation (equivalent to the UV-B radiation normally incident at Tokyo, 36°N latitude, during clear sky conditions in mid-april on a weighted daily fluence basis) and a UV-B-free control condition. UV-B irradiation inhibited the growth of the cotyledons, i.e. the increase in area, and increase in fresh and dry weights of the cotyledons. The greatest inhibition rate was observed in the increase in area, causing a significant increase in specific leaf weight (the ratio of weight to area). UV-B irradiation had no significant effect on DNA and RNA contents in the cotyledons, but decreased protein content slightly. In contrast, the irradiation reduced the amounts of organic acids and soluble sugars, indicating that primary carbon metabolism was very sensitive to UV-B radiation. UV-B irradiation lowered the photosynthetic activity in the cotyledons without any effect on chlorophyll content and respiratory activity. These results indicate that UV-B radiation at the ambient level may act as a physiological stress in some UV-sensitive plants.     

The lactic acid bacterium Pediococcus acidilactici suppresses autoimmune encephalomyelitis by inducing IL-10-producing regulatory T cells

Background

Certain intestinal microflora are thought to regulate the systemic immune response. Lactic acid bacteria are one of the most studied bacteria in terms of their beneficial effects on health and autoimmune diseases; one of which is Multiple sclerosis (MS) which affects the central nervous system. We investigated whether the lactic acid bacterium Pediococcus acidilactici, which comprises human commensal bacteria, has beneficial effects on experimental autoimmune encephalomyelitis (EAE), an animal model of MS.

Methodology/Principal Findings

P. acidilactici R037 was orally administered to EAE mice to investigate the effects of R037. R037 treatment suppressed clinical EAE severity as prophylaxis and therapy. The antigen-specific production of inflammatory cytokines was inhibited in R037-treated mice. A significant increase in the number of CD4⁺ Interleukin (IL)-10-producing cells was observed in the mesenteric lymph nodes (MLNs) and spleens isolated from R037-treated naive mice, while no increase was observed in the number of these cells in the lamina propria. Because only a slight increase in the CD4⁺Foxp3⁺ cells was observed in MLNs, R037 may primarily induce Foxp3⁻ IL10-producing T regulatory type 1 (Tr1) cells in MLNs, which contribute to the beneficial effect of R037 on EAE.

Conclusions/Significance

An orally administered single strain of P. acidilactici R037 ameliorates EAE by inducing IL10-producing Tr1 cells. Our findings indicate the therapeutic potential of the oral administration of R037 for treating multiple sclerosis.     

Cytological diagnostic clues in poorly differentiated squamous cell carcinomas of the breast: Streaming arrangement,necrotic background,nucleolar enlargement and cannibalism of cancer cells

Objective

Squamous cell carcinoma (SCC) is a rare histological type of breast cancer. The cytological diagnosis of non‐keratinising, poorly differentiated SCC is often difficult, and distinguishing it from invasive ductal carcinoma or apocrine carcinoma (AC) is especially challenging. We aimed to define the diagnostic cytological features of poorly differentiated SCC of the breast.

Methods

We studied the cytological findings of poorly differentiated SCC (n=10) and compared them to those of IDC (n=15) and AC (n=14). The following six cytological features were evaluated: streaming arrangement, nucleolar enlargement, dense nuclei, cannibalism, atypical keratinocytes and necrotic background.

Results

SCC exhibited significantly higher frequencies of streaming arrangement (70% vs 6.7%, P=.002), nucleolar enlargement (80% vs 27%, P=.02), and necrotic background (80% vs 36%, P=.002) than invasive ductal carcinoma. The detection of two or three of these features yielded a higher sensitivity (80%) and specificity (93%) for the diagnosis of SCC. Streaming arrangement (70% vs 0%, P<.001), cannibalism (60% vs 0%, P=.002), and a necrotic background (80% vs 36%, P=.047) were all significantly more frequent in SCC than in AC. When distinguishing SCC from AC, the presence of two or three of these features yielded a high sensitivity (80%) and specificity (100%).

Conclusions

Cytological features such as a streaming arrangement, a necrotic background, nucleolar enlargement and cannibalism are useful indicators for the diagnosis of SCC of the breast. As such, greater attention should be paid to these morphological features in daily clinical practice.     

Blue light induced inhibition of seed germination: The necessity of the fruit coats for the blue light response

The seeds (achenes) of Laportea bulbifera require a chilling to break their dormancy and are negatively photoblastic. Their germination is inhibited by both continuous blue light and continuous or prolonged far-red radiation. The germination of de-coated seeds, prepared by removing the fruit coats, however, was strongly inhibited by continuous far-red, but not by continuous blue light. Photoreversible germination by a brief irradiation with red light occurred when the chilled seeds were exposed to prolonged far-red light. These results suggest that far-red light may regulate the germination of L. bulbifera seeds through the phytochrome system which exists in the regions other than fruit coats and that the blue light reaction may be governed by other photoreceptor system(s).     

Prostaglandin stimulation of adenosine 3',5'-monophosphate accumulation in cultured chondrocytes in the presence or absence of parathyroid hormone

The effect of prostaglandin analogues on the cyclic AMP level in cultured chondrocytes were examined. Prostaglandin E1 at 0.4 to 30 microM, increased the intracellular concentration of cyclic AMP in chondrocytes. Its effect was rapid, being evident within 1 min and reaching a maximum in 10 to 20 min. The maximum level was sustained until 30 min after its addition and then decreased gradually. Prostaglandin D2 and E2 also increased the cyclic AMP level in chondrocytes, but they had less effect than prostaglandin E1. Prostaglandin A1 had no effect on the nucleotide level in chondrocytes, although they markedly increased the level in fibroblasts. The time course of stimulation of cyclic AMP accumulation in chondrocytes by prostaglandin E1, D2 or E2 was quite different from that by parathyroid hormone (PTH): the effect of prostaglandin was slower and more sustained than that of PTH. PTH potentiated the effect of prostaglandin E1, E2, or D2 on the cyclic AMP level in chondrocytes and that the combined effects of prostaglandin and PTH were more than additive. Addition of an inhibitor of cyclic nucleotide phosphodiesterase with prostaglandin, PTH or both produced a synergistic effect on the accumulation of cyclic AMP in the chondrocytes. These findings suggest that prostaglandin E1, E2, and D2 increase the synthesis of cyclic AMP and that the combined effect of the prostaglandins and PTH on the cyclic AMP level in chondrocytes is partly attributed to the synergistic synthesis of cyclic AMP in the cells.     

Photoactivation of the latent water-oxidizing complex in photosystem II membranes isolated from dark-grown spruce seedlings

Photosystem II membranes (D-PSII) were isolated from dark-grown spruce seedlings. All major PSII proteins except the 17- and 23-kDa extrinsic proteins were present in D-PSII. O₂ evolution and Mn content in D-PSII were negligible, while PSII-donor activity showed a value comparable to that of NH₂OH-treated PSII membranes (NH₂OH-L-PSII) from light-grown seedlings. Light incubation of D-PSII with 1 m M MnCl₂, 50 m M CaCl₂ and 100 μ M DCIP at pH 5.3 resulted in activation of the latent water-oxidizing complex. Accomplishment of photoactivation of PSII membranes from dark-grown spruce seedlings clearly indicates that only ligation of Mn²⁺ to the apo-water oxidizing complex is required for expression of O₂ evolution, and that protein synthesis is not involved in the photoactivation process. There was no essential difference between 'photoactivation' of naturally Mn-free PSII membranes and 'photoreactivation' of artificially Mn-depleted PSII membranes on kinetics, pH dependence, Mn²⁺-concentration dependence. However, kinetics and pH dependence of photoactivation were appreciably different in spruce PSII membranes and in PSII membranes of angiosperms such as wheat and spinach.     

Landscape of protein–small ligand binding modes

Elucidating the mechanisms of specific small‐molecule (ligand) recognition by proteins is a long‐standing conundrum. While the structures of these molecules, proteins and ligands, have been extensively studied, protein–ligand interactions, or binding modes, have not been comprehensively analyzed. Although methods for assessing similarities of binding site structures have been extensively developed, the methods for the computational treatment of binding modes have not been well established. Here, we developed a computational method for encoding the information about binding modes as graphs, and assessing their similarities. An all‐against‐all comparison of 20,040 protein–ligand complexes provided the landscape of the protein–ligand binding modes and its relationships with protein‐ and chemical spaces. While similar proteins in the same SCOP Family tend to bind relatively similar ligands with similar binding modes, the correlation between ligand and binding similarities was not very high (R² = 0.443). We found many pairs with novel relationships, in which two evolutionally distant proteins recognize dissimilar ligands by similar binding modes (757,474 pairs out of 200,790,780 pairs were categorized into this relationship, in our dataset). In addition, there were an abundance of pairs of homologous proteins binding to similar ligands with different binding modes (68,217 pairs). Our results showed that many interesting relationships between protein–ligand complexes are still hidden in the structure database, and our new method for assessing binding mode similarities is effective to find them.     

A high-molecular-weight,alkaline, and thermostable β-1,4-xylanase of a subseafloor <Emphasis Type="Italic">Microcella alkaliphila</Emphasis>

An endo β-1,4-xylanase (XynE15) from a culture broth of a deep subseafloor microorganism, Microcella alkaliphila JAM-AC0309, was purified to homogeneity. The molecular mass of XynE15 was approximately 150 kDa as judged by SDS-PAGE. The optimal pH and temperature for hydrolysis of xylan were pH 8 and 65 °C. The enzyme was stable to incubation for 30 min at up to 75 °C, and the half-life at 50 °C was 48 h. XynE15 hydrolyzed arabinoxylan, oat spelt xylan, and birchwood xylan well, but not avicel, carboxymethylcellulose, or arabinan. Xylooligosaccharides were hydrolyzed to mainly xylobiose from higher than xylotetraose. The genome sequencing analysis of strain JAM-AC03039 revealed that XynE15 was composed of 1,319 amino acids with one catalytic domain and three carbohydrate-binding domains belonging to glycoside hydrolase (GH) family 10 and carbohydrate-binding module (CBM) family 4, respectively.     

Difference of pine ectomycorrhizal biomass in relation to forest conditions

In this study, two plots in a secondary and another two in planted Pinus densiflora stands were exposed to different forest treatments, and the ectomycorrhizal (EM) biomass and its ergosterol content was measured for a year. The unmanaged plot in the secondary stand had greater EM biomass than those in any other plots. Whereas understory cutting had less effect on EM biomass, litter and humus removal decreased pine EM biomass and its ergosterol content, suggesting that such forest treatment alters EM biomass and its structure.