Genomic and Metagenomic Insights into the Distribution of Nicotine-degrading Enzymes in Human Microbiota.

Introduction: Nicotine degradation is a new strategy to block nicotine-induced pathology. The potential of human microbiota to degrade nicotine has not been explored. Aims: This study aimed to uncover the genomic potentials of human microbiota to degrade nicotine. Methods: To address this issue, we performed a systematic annotation of Nicotine-Degrading Enzymes (NDEs) from genomes and metagenomes of human microbiota. A total of 26,295 genomes and 1,596 metagenomes for human microbiota were downloaded from public databases and five types of NDEs were annotated with a custom pipeline. We found 959 NdhB, 785 NdhL, 987 NicX, three NicA1, and three NicA2 homologs. Results: Genomic classification revealed that six phylum-level taxa, including Proteobacteria, Firmicutes, Firmicutes_A, Bacteroidota, Actinobacteriota, and Chloroflexota, can produce NDEs, with Proteobacteria encoding all five types of NDEs studied. Analysis of NicX prevalence revealed differences among body sites. NicX homologs were found in gut and oral samples with a high prevalence but not found in lung samples. NicX was found in samples from both smokers and non-smokers, though the prevalence might be different. Conclusion: This study represents the first systematic investigation of NDEs from the human microbiota, providing new insights into the physiology and ecological functions of human microbiota and shedding new light on the development of nicotine-degrading probiotics for the treatment of smoking-related diseases.

A theoretical insight into excited-state decay and proton transfer of p-nitrophenylphenol in the gas phase and methanol solution.

The excited-state decay (ESD) and proton transfer (EPT) of p-nitrophenylphenol (NO2-Bp-OH), especially in the triplet states, were not characterized with high-level theoretical methods to date. Herein, the MS-CASPT2//CASSCF and QM(MS-CASPT2//CASSCF)/MM methods were employed to gain an atomic-level understanding of the ESD and EPT of NO2-Bp-OH in the gas phase and its hydrogen-bonded complex in methanol. Our calculation results revealed that the S1 and S2 states of NO2-Bp-OH are of 1ππ* and 1nπ* characters at the Franck-Condon (FC) point, which correspond to the ICT-EPT and intramolecular charge-transfer (ICT) states in spectroscopic experiments. The former state has a charge-transfer property that could facilitate the EPT reaction, while the latter one might be unfavorable for EPT. The vertical excitation energies of these states are almost degenerate at the FC region and the electronic configurations of 1ππ* and 1nπ* will exchange from the S1 FC region to the S1 minimum, which means that the 1nπ* state will participate in ESD once NO2-Bp-OH departs from the S1 FC region. Besides, we found that three triplets lie below the first bright state and will play very important roles in intersystem crossing processes. In terms of several pivotal surface crossings and relevant linearly interpolated internal coordinate (LIIC) paths, three feasible but competing ESD channels that could effectively lead the system to the ground state or the lowest triplet state were put forward. Once arrived at the T1 state, the system has enough time and internal energy to undergo the EPT reaction. The methanol solvent has a certain effect on the relative energies and spin-orbit couplings, but does not qualitatively change the ESD processes of NO2-Bp-OH. By contrast, the solvent effects will remarkably stabilize the proton-transferred product by the hydrogen bond networks and assist to form the triplet anion. Our present work would pave the road to properly understand the mechanistic photochemistry of similar hydroxyaromatic compounds.

Theoretical studies on the photochemistry of 2-nitrofluorene in the gas phase and acetonitrile solution.

The photophysical and photochemical mechanisms of 2-nitrofluorene (2-NF) in the gas phase and acetonitrile solution have been studied theoretically. Upon ∼330 nm irradiation to the first bright state (1ππ*), the 2-NF system can decay to triplet excited states via rapid intersystem crossing (ISC) processes through different surface crossing points or to the ground state via an ultrafast internal conversion (IC) process through the S1/S0 conical intersection. The 1nπ* dark state will serve as a bridge when the system leaves the Franck-Condon (FC) region and approaches to the S1 minimum. The molecule maintains a planar geometry during the excited-state relaxation processes. The differences on excitation properties such as electronic configurations and spin-orbit coupling (SOC) interactions between those in the gas phase and acetonitrile solution cannot be neglected, indicating possible changes on the efficiency of the related ISC processes for the 2-NF system in solution. Once arrived at the T1 state, it would further decay to the S0 state or photodegrade into the Ar-O˙ and NO˙ free radicals. During the intramolecular rearrangement process, the twisting of the nitro group out of the aromatic-ring plane is regarded as a critical structural variation for the photodegradation of the 2-NF system. The free radicals finally form through oxaziridine-type intermediate and transition state structures. The present work provides important mechanistic insights to the photochemistry of nitro-substituted polyaromatic compounds.

Shewanella polaris sp. nov., a psychrotolerant bacterium isolated from Arctic brown algae.

A Gram-stain-negative, facultatively anaerobic, flagellated and rod-shaped bacterium, designated strain SM1901T, was isolated from a brown algal sample collected from Kings Bay, Svalbard, Arctic. Strain SM1901T grew at -4‒30 °C and with 0-7.0 % (w/v) NaCl. It reduced nitrate to nitrite and hydrolysed DNA and Tween 80. Results of phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SM1901T was affiliated with the genus Shewanella, showing the highest sequence similarity to the type strain of Shewanella litoralis (97.5%), followed by those of Shewanella vesiculosa, Shewanella livingstonensis and Shewanella saliphila (97.3 % for all three). The major cellular fatty acids were summed feature 3 (C16 : 1 ω7с and/or C16 : 1 ω6с), C16 : 0, C18 : 0, iso-C15 : 0 and C17 : 1 ω8с and the major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. The respiratory quinones were ubiquinones Q-7, Q-8, menaquinones MK-7(H) and MK-8. The genome of strain SM1901T was 4648537 nucleotides long and encoded a variety of cold adaptation related genes, providing clues for better understanding the ecological adaptation mechanisms of polar bacteria. The genomic DNA G+C content of strain SM1901T was 40.5 mol%. Based on the polyphasic evidence presented in this paper, strain SM1901T was considered to represent a novel species, constituting a novel psychrotolerant lineage out of the known SF clade encompassed by polar Shewanella species, within the genus Shewanella, for which the name Shewanella polaris sp. nov. is proposed. The type strain is SM1901T (=KCTC 72047T=MCCC 1K03585T).

[Spatial distribution characteristics and influencing factors of eco-environmental quality based on RS and GIS in Shiyang River Basin, China.] / 基于RS和GISçš„çŸ³ç¾Šæ²³æµåŸŸç”Ÿæ€çŽ¯å¢ƒè´¨é‡ç©ºé—´åˆ†å¸ƒç‰¹å¾åŠå ¶å½±å“å› ç´ .

Based on RS and GIS, 11 indexes from three aspects including natural capital, social pressure and economic supports were selected. The natural capital index (NCI), social pressure index (SPI), economic support index (ESI), and environment quality evaluation index (EQEI) were constructed by using spatial principal component analysis, variation coefficient method, and analytic hierarchy process. The spatial distribution characteristics and influencing factor of the environmental quality in Shiyang River Basin were analyzed. The results showed that the overall environmental quality was at poor level in Shiyang River Basin. The regions with better classes of environmental quality were mainly concentrated in the upper reaches of Qilian Mountains, and those with poorer classes were mainly concentrated in the middle-lower reaches of low hills land and desert. The EQEI value in Shiyang River Basin had polarization phenomenon from southwest to northeast. With the variation of distance, the value had large variation range, with obvious spatial heterogeneity. The environmental quality showed both high and low aggregation patterns, with "fault" distribution. There were highly clustered hot spots and highly clustered cold spots in the basin. Among the influen-cing factors of environmental quality, natural capital was the dominant one, social pressure was the second, and economic support was the least contributor.

Erythrobacter xanthus sp. nov., isolated from surface seawater of the South China Sea.

A Gram-reaction-negative, aerobic, oxidase- and catalase-positive, yellow-pigmented, non-flagellated, rod-shaped bacterium, designed strain SM1501T, was isolated from surface seawater of the South China Sea. SM1501T grew at 7-42 °C and with 0-11 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that SM1501T represented a member of the genus Erythrobacter, sharing the highest 16S rRNA gene sequence similarity (97.4 %) with Erythrobacter luteus and 94.2-96.5 % 16S rRNA gene sequence similarities to other species of the genus Erythrobacterwith validly published names. The average nucleotide identity (ANI) value and in silico DNA-DNA hybridization value between SM1501T and E. luteus were only 74.6 and 20.0 %, respectively. The predominant cellular fatty acids of SM1501T were C17 : 1ω6c, C18 : 1ω7c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The major polar lipids of the strain were phosphatidylethanolamine, phosphatidylglycerol, sphingoglycolipid, diphosphatidylglycerol and phosphatidylcholine and the main respiratory quinone of was Q-10. Polyphasic data presented in this paper support the notion that SM1501T represents a novel species in the genus Erythrobacter, for which the name Erythrobacter xanthus sp. nov. is proposed. The type strain of Erythrobacterxanthus is SM1501T (=KCTC 42669T=CCTCC AB 2015396T).

The excited-state decay mechanism of 2,4-dithiothymine in the gas phase, microsolvated surroundings, and aqueous solution.

The photophysics of thiothymines has been extensively studied computationally in the past few years due to their significant potential as photosensitizers in photodynamic therapy. However, the corresponding computational studies of the photophysical mechanism of 2,4-dithiothymine are scarce. Herein we have employed the CASPT2//CASSCF and QM(CASPT2//CASSCF)/MM methods to systematically explore the excited-state decay mechanism of 2,4-dithiothymine in isolated, microsolvated, and aqueous surroundings. First, we have optimized minima and conical intersections in and between the lowest six excited singlet and triplet states i.e., , , , , and ; then, based on computed excited-state decay paths and spin-orbit couplings, we have proposed several nonadiabatic pathways that efficiently populate the lowest triplet state to explain the experimentally observed ultrahigh triplet-state quantum yield. Moreover, we have found that the excited-state decay mechanism in microsolvated and aqueous environments is more complicated than that in the gas phase. The solute-solvent interaction has significant effects on the excited-state potential energy surfaces of 2,4-dithiothymine and eventually on its excited-state decay mechanism. Finally, the present computational efforts contribute important mechanistic knowledge to the understanding of the photophysics of thiothymine-based photosensitizers.

Cellular and molecular insight into the inhibition of primary root growth of Arabidopsis induced by peptaibols, a class of linear peptide antibiotics mainly produced by Trichoderma spp.

Trichoderma spp. are well known biocontrol agents that produce a variety of antibiotics. Peptaibols are a class of linear peptide antibiotics mainly produced by Trichoderma Alamethicin, the most studied peptaibol, is reported as toxic to plants at certain concentrations, while the mechanisms involved are unclear. We illustrated the toxic mechanisms of peptaibols by studying the growth-inhibitory effect of Trichokonin VI (TK VI), a peptaibol from Trichoderma longibrachiatum SMF2, on Arabidopsis primary roots. TK VI inhibited root growth by suppressing cell division and cell elongation, and disrupting root stem cell niche maintenance. TK VI increased auxin content and disrupted auxin response gradients in root tips. Further, we screened the Arabidopsis TK VI-resistant mutant tkr1. tkr1 harbors a point mutation in GORK, which encodes gated outwardly rectifying K(+)channel proteins. This mutation alleviated TK VI-induced suppression of K(+)efflux in roots, thereby stabilizing the auxin gradient. The tkr1 mutant also resisted the phytotoxicity of alamethicin. Our results indicate that GORK channels play a key role in peptaibol-plant interaction and that there is an inter-relationship between GORK channels and maintenance of auxin homeostasis. The cellular and molecular insight into the peptaibol-induced inhibition of plant root growth advances our understanding of Trichoderma-plant interactions.

Diversity of cultivable protease-producing bacteria in sediments of Jiaozhou Bay, China.

Although protease-producing bacteria are key players in the degradation of organic nitrogen and essential for the nitrogen recycling in marine sediments, diversity of both these bacteria and their extracellular proteases is still largely unknown. This study investigated the diversity of the cultivable protease-producing bacteria and their extracellular proteases in the sediments of the eutrophied Jiaozhou Bay, China through phylogenetic analysis and protease inhibitor tests. The abundance of the cultivable protease-producing bacteria was up to 10(4) cells/g in all six sediment samples. The cultivated protease-producing bacteria mostly belonged to the phyla Proteobacteria and Firmicutes with the predominant genera being Photobacterium (39.4%), Bacillus (25.8%), and Vibrio (19.7%). Protease inhibitor tests revealed that extracellular proteases secreted by the bacteria were mainly serine proteases and/or metalloproteases with relatively low proportions of cysteine proteases. This study represents the first comprehensive analysis on the diversity of protease-producing bacteria and their extracellular proteases in sediments of a eutrophic bay.

Algimonas arctica sp. nov., isolated from intertidal sand, and emended description of the genus Algimonas.

A novel Gram-reaction-negative, aerobic, pale-orange-pigmented bacterium, designated strain SM1216T, was isolated from Arctic intertidal sand. Cells of strain SM1216T were dimorphic rods with a single polar prostheca or flagellum. The strain grew at 4 − 30 °C (optimum at 25 °C) and with 0.5 − 6 % (w/v) NaCl (optimum with 2 − 3 %). It reduced nitrate to nitrite but did not hydrolyse gelatin, DNA or Tween 80. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM1216T was affiliated with the genus Algimonas in the family Hyphomonadaceae, sharing 97.5 and 96.3 % similarity with Algimonas ampicilliniresistens 14A-2-7T and Algimonas porphyrae 0C-2-2T, respectively, the two known species in the genus Algimonas. However, the level of DNA­DNA relatedness between strain SM1216T and the type strain of A. ampicilliniresistens, the nearest phylogenetic neighbour, was 57.9 %. The major cellular fatty acids of strain SM1216T were C18 : 1ω7c and C18 : 1 2-OH. The main polar lipids of strain SM1216T were monoglycosyldiglyceride (MGDG), glucuronopyranosyldiglyceride (GUDG), phosphatidylglycerol (PG) and three unidentified phospholipids (PL1­3). The major respiratory quinone was ubiquinone 10 (Q10). The genomic G+C content of strain SM1216T was 60.6 mol%. On the basis of the evidence from this polyphasic study, strain SM1216T represents a novel species in the genus Algimonas, for which the name Algimonas arctica sp. nov. is proposed. The type strain is SM1216T ( = MCCC 1K00233T = KCTC 32513T). An emended description of the genus Algimonas is also given.

Haliea atlantica sp. nov., isolated from seawater, transfer of Haliea mediterranea to Parahaliea gen. nov. as Parahaliea mediterranea comb. nov. and emended description of the genus Haliea.

A novel Gram-stain-negative, oxidase- and catalase-positive, aerobic bacterium, designated strain SM1351T, was isolated from surface seawater of the Atlantic Ocean. This strain grew at 4-45 °C and with 5-90 g NaCl l- 1. It did not reduce nitrate to nitrite and could not hydrolyse starch or DNA. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the strain was affiliated with the genus Haliea in the family Alteromonadaceae, with sequence similarities with the type strains of Haliea salexigens and Haliea mediterranea, the two recognized species of the genus Haliea, of 96.2 and 94.6 %, respectively. The major fatty acids of strain SM1351T were C16 : 1ω7c and/or iso-C15 : 0 2-OH, C17 : 1ω8c, C18 : 1ω7c and C16 : 0 and the major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The major respiratory quinone was ubiquinone Q-8. The genomic DNA G+C content of strain SM1351T was 62 mol%. On the basis of the polyphasic characterization of strain SM1351T in this study, it is considered to represent a novel species in the genus Haliea, for which the name Haliea atlantica sp. nov. is proposed. The type strain is SM1351T ( = CCTCC AB 2014266T = JCM 30304T). Moreover, the transfer of Haliea mediterraneaLucena et al. 2010 to Parahaliea gen. nov. as Parahaliea mediterranea comb. nov. (type strain 7SM29T = CECT 7447T = DSM 21924T) and an emended description of the genus Haliea are also proposed.

Bizionia arctica sp. nov., isolated from Arctic fjord seawater, and emended description of the genus Bizionia.

A Gram-stain-negative, yellow-pigmented, aerobic, non-flagellated, non-gliding bacterial strain, designated SM1203(T), was isolated from surface seawater of Kongsfjorden, Svalbard. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM1203(T) was affiliated with the genus Bizionia in the family Flavobacteriaceae. The strain shared the highest 16S rRNA gene sequence similarity (>96%) with the type strains of Formosa spongicola (96.8%), Bizionia paragorgiae (96.3%), B. saleffrena (96.3%) and B. echini (96.1%) and 95.4-95.7% sequence similarity with the type strains of other known species of the genus Bizionia. The strain grew at 4-30 °C and in the presence of 1.0-5.0% (w/v) NaCl. The major fatty acids of strain SM1203(T) were iso-C15 : 0, iso-C15 : 1, anteiso-C15 : 0 and C15 : 0 and the main polar lipids were phosphatidylethanolamine and an unidentified lipid. The major respiratory quinone of strain SM1203(T) was menaquinone 6 (MK-6). The genomic DNA G+C content of strain SM1203(T) was 34.8 mol%. Based on the polyphasic characterization of strain SM1203(T) in this study, the strain represents a novel species in the genus Bizionia, for which the name Bizionia arctica sp. nov. is proposed. The type strain is SM1203(T) ( = CGMCC 1.12751(T) = JCM 30333(T)). An emended description of the genus Bizionia is also given.

Marivirga atlantica sp. nov., isolated from seawater and emended description of the genus Marivirga.

A novel Gram-stain-negative, aerobic, orange-pigmented, non-flagellated, gliding, rod-shaped bacterium, designated strain SM1354(T) was isolated from surface seawater of the Atlantic Ocean. The strain hydrolysed gelatin and DNA but did not reduce nitrate. It grew at 4-40 °C and with 0.5-11% (w/v) NaCl. Phylogenetic analysis of the 16S rRNA gene sequences revealed that strain SM1354(T) belonged to the genus Marivirga with 96.0-96.2% sequence similarities to known species of the genus Marivirga . The major fatty acids of strain SM1354(T) were iso-C15 : 0, iso-C15 : 1 G, iso-C17 : 03-OH and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 02-OH). Polar lipids of strain SM1354(T) included phosphatidylethanolamine, three unidentified lipids and one unidentified aminolipid and aminophospholipid. The major respiratory quinone of strain SM1354(T) was menaquinone 7 (MK-7). The genomic DNA G+C content of strain SM1354(T) was 33.9 ± 0.4 mol%. On the basis of the results of the polyphasic characterization in this study, it is proposed that strain SM1354(T) represents a novel species of the genus Marivirga , namely Marivirga atlantica sp. nov. The type strain of Marivirga atlantica is SM1354(T) ( =CCTCC AB 2014242(T) =JCM 30305(T)). An emended description of the genus Marivirga is also proposed.

Differentiation of retinal ganglion cells and photoreceptor precursors from mouse induced pluripotent stem cells carrying an Atoh7/Math5 lineage reporter.

The neural retina is a critical component of the visual system, which provides the majority of sensory input in humans. Various retinal degenerative diseases can result in the permanent loss of retinal neurons, especially the light-sensing photoreceptors and the centrally projecting retinal ganglion cells (RGCs). The replenishment of lost RGCs and the repair of optic nerve damage are particularly challenging, as both RGC specification and their subsequent axonal growth and projection involve complex and precise regulation. To explore the developmental potential of pluripotent stem cell-derived neural progenitors, we have established mouse iPS cells that allow cell lineage tracing of progenitors that have expressed Atoh7/Math5, a bHLH transcription factor required for RGC production. These Atoh7 lineage reporter iPS cells encode Cre to replace one copy of the endogenous Atoh7 gene and a Cre-dependent YFP reporter in the ROSA locus. In addition, they express pluripotent markers and are capable of generating teratomas in vivo. Under anterior neural induction and neurogenic conditions in vitro, the Atoh7-Cre/ROSA-YFP iPS cells differentiate into neurons that co-express various RGC markers and YFP, indicating that these neurons are derived from Atoh7-expressing progenitors. Consistent with previous in vivo cell lineage studies, the Atoh7-Cre/ROSA-YFP iPS cells also give rise to a subset of Crx-positive photoreceptor precursors. Furthermore, inhibition of Notch signaling in the iPSC cultures results in a significant increase of YFP-positive RGCs and photoreceptor precursors. Together, these results show that Atoh7-Cre/ROSA-YFP iPS cells can be used to monitor the development and survival of RGCs and photoreceptors from pluripotent stem cells.

Marinicauda pacifica gen. nov., sp. nov., a prosthecate alphaproteobacterium of the family Hyphomonadaceae isolated from deep seawater.

A marine prosthecate bacterium, designated strain P-1 km-3(T), was isolated from deep seawater from the Pacific. Cells of strain P-1 km-3(T) were Gram-stain-negative, aerobic, catalase- and oxidase-positive, dimorphic rods with a single polar prostheca or flagellum. The strain hydrolysed gelatin and grew at 6-40 °C (optimum, 30 °C) and with 0.5-12% (w/v) NaCl (optimum, 2%). Phylogenetic analysis of the 16S rRNA gene sequences revealed that strain P-1 km-3(T) belonged to the family Hyphomonadaceae in the class Alphaproteobacteria and represented a separate lineage, located between the genera Oceanicaulis and Woodsholea. Sequence similarities of strain P-1 km-3(T) with type strains of species of the genera Oceanicaulis and Woodsholea were 93.2-93.9%. The predominant cellular fatty acids in strain P-1 km-3(T) were C18:1ω7c, C18:0, 11-methyl C18:1ω7c, C17:0 and C19:0 cyclo ω8c. The major respiratory quinone of strain P-1 km-3(T) was Q-10. The polar lipids of strain P-1 km-3(T) comprised glucuronopyranosyldiglyceride (GUDG), monoglycosyldiglyceride (MGDG), sulfo-quinovosyl diacylglycerol (SQDG), phosphatidylglycerol (PG), an unidentified phospholipid (PL) and an unidentified lipid (L). The genomic DNA G+C content of strain P-1 km-3(T) was 66.0 mol%. On the basis of the polyphasic data presented in this study, strain P-1 km-3(T) is proposed to represent a novel species in a new genus, Marinicauda pacifica gen. nov., sp. nov., within the family Hyphomonadaceae. The type strain of the type species is P-1 km-3(T) (=KACC 16526(T)=CGMCC 1.11031(T)).

Early changes in morphology and intraocular pressure by size of clear corneal incision.

PURPOSE: We compared changes in morphology and intraocular pressure (IOP) induced by clear 2.2-mm and 3.0-mm corneal incisions in a cohort of patients with cataracts. METHODS: In 160 eyes (from 70 men and 90 women at the Ophthalmic Center of Sun Yat-sen University), optical coherence tomography and tonometry were performed at 1, 5, and 24 hours after cataract surgery. The main outcome measures were IOP, postoperative changes in Descemet membrane detachment (DMD), healing of the surgical incision, and inflammation of the anterior chamber. RESULTS: Five hours after surgery, patients with 2.2-mm and 3.0-mm incisions had lower IOPs (P < 0.017) as measured by noncontact tonometry, but the difference was significant only among patients with grade V cataracts (2.2 mm, 12.6 ± 1.2 mm Hg; 3.0 mm, 14.5 ± 0.9 mm Hg, P < 0.05). The incidence of endothelial gap at 24 hours after surgery was significantly higher in the 2.2-mm (50%) versus 3.0-mm (11.1%) group of patients with grade V cataracts (P < 0.05). The incidence of DMD at 5 hours was also significantly higher in the 2.2-mm group (75%) than in the 3.0-mm group (22.2%) only among patients with this grade (P < 0.05). CONCLUSIONS: Incision width made no difference among patients with grade I-IV lens nuclei; but among those with grade V, 3.0-mm incisions had significantly less endothelial gaping, less DMD, and higher mean IOPs. For these patients, smaller incisions may not be optimal, and eyes may be especially vulnerable within 5 hours of surgery.

The supramolecular architecture, function, and regulation of thylakoid membranes in red algae: an overview.

Red algae are a group of eukaryotic photosynthetic organisms. Phycobilisomes (PBSs), which are composed of various types of phycobiliproteins and linker polypeptides, are the main light-harvesting antennae in red algae, as in cyanobacteria. Two morphological types of PBSs, hemispherical- and hemidiscoidal-shaped, are found in different red algae species. PBSs harvest solar energy and efficiently transfer it to photosystem II (PS II) and finally to photosystem I (PS I). The PS I of red algae uses light-harvesting complex of PS I (LHC I) as a light-harvesting antennae, which is phylogenetically related to the LHC I found in higher plants. PBSs, PS II, and PS I are all distributed throughout the entire thylakoid membrane, a pattern that is different from the one found in higher plants. Photosynthesis processes, especially those of the light reactions, are carried out by the supramolecular complexes located in/on the thylakoid membranes. Here, the supramolecular architecture, function and regulation of thylakoid membranes in red algal are reviewed.

Differentiation of SWO-38 glioma cells induced by CDA-2 is mediated by peroxisome proliferator-activated receptor gamma.

Glioma remains one of the most lethal human tumors in spite of the progress in radiotherapy, chemotherapy, and surgical techniques. Cell differentiation agent-2 (CDA-2) is an extraction from healthy human urine consisting of primary organic acids and peptides, and it has been demonstrated to inhibit growth and induce differentiation in glioma and other cell lines. However, the mechanism remains unclear. Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptors (NHRs) which are involved in cellular differentiation and proliferation. In this study, we investigated if CDA-2 induced differentiation of SWO-38 glioma cells is mediated by PPARgamma. CDA-2 induced differentiation of SWO-38 cells was characterized by typical morphological changes, increased expression of GFAP, inhibition of proliferation and G(0)/G(1) cell cycle arrest. CDA-2 also triggered up-regulation of PPARgamma, GFAP and PTEN protein and a reduction of COX-2 protein. However, the effects of CDA-2 on SWO-38 cells could be partly reversed by GW9662, an irreversible PPARgamma antagonist. Our investigation demonstrated that CDA-2 could be a potential drug for tumor differentiation therapy, and activation of the PPARgamma pathway might be a crucial factor in glioma differentiation induced by CDA-2.

Autolysis of a novel multidomain subtilase-cold-adapted deseasin MCP-01 is pH-dependent and the surface loops in its catalytic domain, the linker, and the P_proprotein domain are susceptible to proteolytic attack.

Cold-adapted deseasin MCP-01 is a novel type subtilase with a multidomain structure containing a catalytic domain, a linker, a P_proprotein domain, and a PKD domain. Its autolysis was pH-dependent due to its flexible structure. N-terminal sequence analysis of the autolytic peptides revealed four autolytic sites in the catalytic domain. Three of these are in the same loops as mesophilic subtilases and one is unlike anything previously reported. Two autolytic sites were deduced in its linker and three in its P_proprotein domain, indicating the linker and the P_proprotein domain are flexible and susceptible to proteolytic attacks. Therefore, during MCP-01 autolysis, the linker and the P_proprotein domain of MCP-01 were easily attacked by proteolysis, resulting in cleavage of the C-terminal region. At the same time, some autolytic sites in the surface loops of the catalytic domain were cleaved. This is the first report describing the autolytic mechanism of a multidomain subtilase.