Viridis Strains Research Articles

New investigation of encoding secondary metabolites gene by genome mining of a marine bacterium, Pseudoalteromonas viridis BBR56

Pseudoalteromonas viridis strain BBR56 was isolated from seawater at Dutungan Island, South Sulawesi, Indonesia. Bacterial DNA was isolated using Promega Genomic DNA TM050. DNA purity and quantity were assessed using NanoDrop spectrophotometers and Qubit fluorometers. The DNA library and sequencing were prepared using Oxford Nanopore Technology GridION MinKNOW 20.06.9 with long read, direct, and comprehensive analysis. High accuracy base calling was assessed with Guppy version 4.0.11. Filtlong and NanoPlot were used for filtering and visualizing the FASTQ data. Flye (2.8.1) was used for de novo assembly analysis. Variant calls and consensus sequences were created using Medaka. The annotation of the genome was elaborated by DFAST. The assembled genome and annotation were tested using Busco and CheckM. Herein, we found that the highest similarity of the BBR56 isolate was 98.37% with the 16 S rRNA gene sequence of P. viridis G-1387. The genome size was 5.5 Mb and included chromosome 1 (4.2 Mbp) and chromosome 2 (1.3 Mbp), which encoded 61 pseudogenes, 4 noncoding RNAs, 113 tRNAs, 31 rRNAs, 4,505 coding DNA sequences, 4 clustered regularly interspaced short palindromic repeats, 4,444 coding genes, and a GC content of 49.5%. The sequence of the whole genome of P. viridis BBR56 was uploaded to GenBank under the accession numbers CP072425–CP072426, biosample number SAMN18435505, and bioproject number PRJNA716373. The sequence read archive (SRR14179986) was successfully obtained from NCBI for BBR56 raw sequencing reads. Digital DNA–DNA hybridization results showed that the genome of BBR56 had the potential to be a new species because no other bacterial genomes were similar to the sample. Biosynthetic gene clusters (BGCs) were assessed using BAGEL4 and the antiSMASH bacterial version. The genome harbored diverse BGCs, including genes that encoded polyketide synthase, nonribosomal peptide synthase, RiPP-like, NRP-metallophore, hydrogen cyanide, betalactone, thioamide-NRP, Lant class I, sactipeptide, and prodigiosin. Thus, BBR56 has considerable potential for further exploration regarding the use of its secondary metabolite products in the human and fisheries sectors.

Предварительная адаптация Dunaliella viridis к сернокислой меди влияет на термоустойчивость культуры

Предварительная адаптация Dunaliella viridis к сернокислой меди влияет на термоустойчивость культуры

Preliminary Adaptation of Dunaliella viridis Strains to Copper Sulfate Affects the Thermal Stability of the Culture

Preliminary Adaptation of Dunaliella viridis Strains to Copper Sulfate Affects the Thermal Stability of the Culture

Blastochloris tepida, sp. nov., a thermophilic species of the bacteriochlorophyll b-containing genus Blastochloris.

A new taxon is created for the thermophilic purple nonsulfur bacterium previously designated as Rhodopseudomonas strain GI. Strain GI was isolated from a New Mexico (USA) hot spring microbial mat and grows optimally above 40°C and to a maximum of 47°C. Strain GI is a bacteriochlorophyll b-containing species of purple nonsulfur bacteria and displays a budding morphology, typical of species of the genus Blastochloris. Although resembling the species Blc. viridis in many respects, the absorption spectrum, carotenoid content, and lipid fatty acid profile of strain GI is distinct from that of Blc. viridis strain DSM133T and other recognized Blastochloris species. Strain GI forms its own subclade within the Blastochloris clade of purple nonsulfur bacteria based on comparative 16S rRNA gene sequences, and its genome is significantly larger than that of strain DSM133T; average nucleotide identity between the genomes of Blc. viridis and strain GI was below 85%. Moreover, concatenated sequence analyses of PufLM and DnaK clearly showed strain GI to be distinct from both Blc. viridis and Blc. sulfoviridis. Because of its unique assortment of properties, it is proposed to classify strain GI as a new species of the genus Blastochloris, as Blc. tepida, sp.n., with strain GIT designated as the type strain (= ATCC TSD-138 = DSM 106918).

Phylogenetic analysis of ITS2 sequences suggests the taxonomic re‐structuring of Dunaliella viridis (Chlorophyceae, Dunaliellales)

SummaryWe analyzed the ITS2 primary and secondary structure (including Compensatory Base Changes (CBCs)) of 17 new Dunaliella strains (11 D. viridis, two D. tertiolecta, and four Dunaliella sp.), and compared these with other Dunaliella sequences available from the ITS2 database to circumscribe their taxonomic position. The ITS2 primary and secondary structure analysis positioned the majority of D. viridis strains in four main clades, showing that D. viridis is polyphyletic. The detection of at least one CBC among these clades strongly suggests that they could correspond to different biological species. Unexpectedly, while D. viridis var. euchlora (CCAP19/21) was positioned within the subgenus Dunaliella, D. viridis var. palmelloides (CCAP11/34) was positioned clearly outside this subgenus, suggesting that this taxon may not be properly placed in Dunaliella. Furthermore, the detection of at least three compensatory base changes (CBCs) between D. viridis var. palmelloides (CCAP11/34) and the other strains analyzed, confirm that this strain is a different species. For these reasons we propose re‐naming D. viridis var. palmelloides (CCAP11/34) to incertae sedis, and D. viridis var. euchlora (CCAP19/21) to Dunaliella sp. Therefore, the ITS2 primary and secondary structure data suggest a taxonomic re‐structuring of D. viridis.

New insights into the structure of the reaction centre from Blastochloris viridis: evolution in the laboratory

Newly determined crystal structures of the photosynthetic RC (reaction centre) from two substrains of the non-sulfur purple bacterium Blastochloris viridis strain DSM 133, together with analysis of their gene sequences, has revealed intraspecies evolutionary changes over a period of 14years. Over 100 point mutations were identified between these two substrains in the four genes encoding the protein subunits of the RC, of which approximately one-fifth resulted in a total of 16 amino acid changes. The most interesting difference was in the M subunit where the change from a leucine residue to glycine in the carotenoid-binding pocket allowed NS5 (1,2-dihydroneurosporene) to adopt a more sterically favoured conformation, similar to the carotenoid conformation found in other related RCs. The results of the present study, together with a high rate of mutations in laboratory bacterial cultures described recently, suggest that bacteria evolve faster than has been generally recognized. The possibility that amino acid changes occur within protein sequences, without exhibiting any immediately observable phenotype, should be taken into account in studies that involve long-term continuous growth of pure bacterial cultures. The Blc. viridis RC is often studied with sophisticated biophysical techniques and changes such as those described here may well affect their outcome. In other words, there is a danger that laboratory-to-laboratory variation could well be due to different groups not realising that they are actually working with slightly different proteins. A way around this problem is suggested.

The importance of morphological versus chemical defences for the bloom-forming cyanobacterium Microcystis against amoebae grazing

Amoebae grazing can be an important loss factor for blooms of the common cyanobacterium Microcystis. Some Microcystis strains seem to be protected against amoebae grazing, but it is unclear whether this is achieved by their colony morphology or biochemically. These factors were investigated in grazing experiments using two Microcystis-grazing amoebae (Korotnevella sp. and Vannella sp.) and two Microcystis strains with differing colony morphology (aeruginosa and viridis morphotype) and different sensitivity to amoebae grazing. Amoebae did not increase in density and failed to reduce the growth rate of cultures of the amoebae insensitive viridis strain, irrespective of whether the Microcystis strain was colonial or unicellular. This suggests that the extended mucilage matrix surrounding viridis colonies is not the main defence mechanism against amoebae grazing. At the same time, the growth rate of both unicellular and colonial cultures of the amoebae-sensitive aeruginosa strain was heavily reduced by the growing amoebae. The addition of filtered viridis-conditioned medium to aeruginosa cultures significantly decreased both amoebae growth and its effect on aeruginosa growth rates, which indicates that extracellular compounds constitutively produced by viridis are at least partially responsible for their insensitivity to amoebae grazing. These results demonstrate the potential importance of chemical interactions between lower trophic levels (protists) for Microcystis bloom dynamics.

Taxonomy of Nephroselmis viridis sp. nov. (Nephroselmidophyceae, Chlorophyta), a sister marine species to freshwater N. olivacea

The genus Nephroselmis (Nephroselmidophyceae), which had been placed in the Prasinophyceae, is one of the primitive green flagellates that are important to our understanding of the early evolution of green plants. We studied a new species of Nephroselmis isolated from Japan, Fiji and South Africa. This species has been known for a long time as undescribed species 'N. viridis.' N. viridis possesses some ultrastructural characters shared with only the freshwater type species N. olivacea, including a disc-like structure beneath the pyrenoid and bipolar spiny body scales with 1-5-8-5-1 spines. Molecular phylogenetic analysis based on 18S rDNA also supports a sister relationship between N. viridis and N. olivacea. However, N. viridis is distinguishable from N. olivacea by the shape of its starch sheath, its scales, its pigment composition and its habitat. In this paper, we designate the formal description of N. viridis sp. nov. We also describe variability in the 18S rDNA introns of various N. viridis strains. This detailed study of N. viridis provides some insights into the evolution of Nephroselmis.

Analysis of absorption spectra of purple bacterial reaction centers in the near infrared region by higher order derivative spectroscopy

Reaction centers (RCs) of purple bacteria are uniquely suited objects to study the mechanisms of the photosynthetic conversion of light energy into chemical energy. A recently introduced method of higher order derivative spectroscopy [I.K. Mikhailyuk, H. Lokstein, A.P. Razjivin, A method of spectral subband decomposition by simultaneous fitting the initial spectrum and a set of its derivatives, J. Biochem. Biophys. Methods 63 (2005) 10–23] was used to analyze the NIR absorption spectra of RC preparations from Rhodobacter ( R.) sphaeroides strain 2R and Blastochloris ( B.) viridis strain KH, containing bacteriochlorophyll (BChl) a and b, respectively. Q y bands of individual RC porphyrin components (BChls and bacteriopheophytins, BPheo) were identified. The results indicate that the upper exciton level P y+ of the photo-active BChl dimer in RCs of R. sphaeroides has an absorption maximum of 810 nm. The blue shift of a complex integral band at approximately 800 nm upon oxidation of the RC is caused primarily by bleaching of P y+, rather than by an electrochromic shift of the absorption band(s) of the monomeric BChls. Likewise, the disappearance of a band peaking at 842 nm upon oxidation of RCs from B. viridis indicates that this band has to be assigned to P y+. A blue shift of an absorption band at approximately 830 nm upon oxidation of RCs of B. viridis is also essentially caused by the disappearance of P y+, rather than by an electrochromic shift of the absorption bands of monomeric BChls. Absorption maxima of the monomeric BChls, B B and B A are at 802 and 797 nm, respectively, in RCs of R. sphaeroides at room temperature. BPheo co-factors H B and H A peak at 748 and 758 nm, respectively, at room temperature. For B. viridis RCs the spectral positions of H B and H A were found to be 796 and 816 nm, respectively, at room temperature.

Toxic cyanobacteria and microcystin concentrations in a public water supply reservoir in the Brazilian Amazonia region

Toxic cyanobacteria in public water supply reservoirs represent a serious health risk as they can release potent cyanotoxins into the water. In the present study we analyzed surface water collected from the Utinga Reservoir, the main source of drinking water for the city of Belém-PA, in order to characterize the reservoir's cyanobacterial biota and to determine the toxicity of these organisms and the concentration of microcystins in raw and treated water. The cyanobacterial biota included potentially toxic genera such as Aphanizomenon, Microcystis, Nostoc, Oscillatoria, Planktothrix and Radiocystis. Mouse bioassays revealed a 43.6% frequency of hepatotoxic strains, including 30.8% Microcystis viridis strains and 12.8% Radiocystis fernandoi strains, with the lowest LD 100 ( ip) of 45 and 75 mg kg −1 body weight, respectively. Subacute hepatotoxicity was observed for Aphanizomenon cf. gracile and Coelomoron pusillum strains. HPLC analysis confirmed the production of microcystins at maximum concentrations of 4.22 μg mg −1 dry weight for M. viridis and 2.47 μg mg −1 for R. fernandoi. Microcystins at concentrations of up to 1.25 μg L −1 detected in raw water by ELISA, together with a cyanobacterial density of 20,000 cells mL −1, represents the first report of a bloom of cyanobacteria for an Amazonian water body.

PHYLOGENETIC ANALYSIS OF THE GENUS EUGLENA (EUGLENOPHYCEAE) WITH PARTICULAR REFERENCE TO THE TYPE SPECIES EUGLENA VIRIDIS1

Euglena viridis (subgenus Euglena) serves as the type species for the genus Euglena. In this study, molecular phylogenetic analyses using a small subunit (SSU) and a combined SSU–partial large subunit rDNA data set for members of the genus Euglena showed that strains identified as E. viridis on the basis of morphology are distributed between two separate nonsister clades. Although all the E. viridis strains examined were morphologically indistinguishable and possessed spherical mucocysts and stellate chloroplasts with one paramylon center, there was a high degree of sequence divergence between the E. viridis strains in different clades, making this a cryptic species. Like E. viridis, all taxa from the subgenus Euglena are characterized by having one or more stellate chloroplasts with paramylon grains clustered around the center of the chloroplast. These additional taxa were divided into four clades in all the molecular analyses. Strains of Euglena stellata formed two nonsister clades whose members had a single aggregate chloroplast with paramylon center and spindle‐shaped mucocysts. A geniculata clade included species with one or two stellate chloroplasts with paramylon centers and spherical mucocysts, and the cantabrica clade had members with one stellate chloroplast with paramylon center and spherical mucocysts often arranged in spiral rows. Interspersed among these were three additional clades bearing taxa from the subgenus Calliglena that contains members with discoid plastids and pyrenoids that may or may not be capped with paramylon. These taxa formed a laciniata clade, mutabilis clade, and gracilis clade. This study demonstrates that E. viridis and E. stellata are cryptic species that can only be distinguished at the molecular level. Because E. viridis is the designated type species for the genus Euglena, we designated an epitype for E. viridis.

Characteristics of microcystin production in the cell cycle of Microcystis viridis.

The correlation between the content of three microcystins (types LR, RR and YR) and the cell cycle of an axenic strain of Microcystis viridis, NIES-102, was investigated under conditions of high (16 mg L(-1)) and low (1.0 mg L(-1)) nitrate (NO(3)-N) concentrations. Each phase of the cell cycle was identified using a flow cytometer equipped with a 488-nm argon laser using SYTOX Green dye, which binds specifically to nucleic acids and can be exited by the wavelength (Ex/Em: 504/523 nm on DNA). Microcystin concentration showed a positive linear correlation with DNA concentration. The microcystin content of the cells changed remarkably as the cell cycle process proceeded, with maximum content in the G(2)/M phase and minimum content in the G(0)/G(1) phase. Under a condition of high NO(3)-N concentration, the ratio of the total content in the G(0)/G(1) phase to that in the G(2)/M phase was about 6:1. In contrast, for the two batch cultures the total content was 1.3-fold greater in the G(2)/M phase. The compositions of the three microcystins also changed along with the cell cycle process, although there was little difference in composition that was related to NO(3)-N concentration. Therefore, there were distinctive compositions specific to each phase of the cycle, and the cell cycle of the M. viridis strain was more strongly responsible for both the quantity and the types of microcystin production than was the effect of NO(3)-N concentration.

151 Phylogenetic Analysis of The Subgenus Euglena with Particualr Reference to the Type Species Euglena Viridis (Euglenophyceae)

Euglena viridis was first described by Antony van Leeuwenhoek in 1674. This taxon later became the type for the genus Euglena erected by Ehrenberg in 1838. The primary characters that distinguish this taxon are the single stellate chloroplast and spherical mucocysts. A number of related Euglena species are similar in size, bear one or two stellate plastids and possess spherical or spindle‐shaped mucocysts. We conducted morphological and molecular studies on taxa in the subgenus Euglena (all of which bear stellate chloroplasts) and compared this to genera in the subgenus Calliglena (non‐stellate chloroplasts). Morphologically the strains in subgenus Euglena were very similar, except for chloroplast number and mucocyst shape. The E. stellata group has one chloroplast and a distinctive spindle‐shaped mucocyst; the E. geniculata group has two chloroplasts and spherical mucocysts; the E. viridis group has one chloroplast and spherical mucocysts. Molecular analyses using SSU and LSU rDNA demonstrated that the subgenus Euglena is not monophyletic. The combined SSU/LSU trees provide strong support for a stellate clade (subgenus Euglena), but one strain of E. viridis diverges at the base of the Euglena/Calliglena lineage. Multiple subclades are found within the main stellate clade. E. tristellata forms a separate divergence and four E. stellata strains form a single, well‐supported subclade. Two E. viridis strains are among the E. geniculata group clade, while six others form two separate, but well‐supported clades. This study demonstrates that the type species, E. viridis, is paraphyletic and will need to be redefined.

Metabolism of pentachlorophenol by Saccharomonospora viridis strains isolated from mushroom compost

A number of actinomycetes were isolated from mushroom compost and screened for the ability to degrade pentachlorophenol (PCP) in liquid medium containing 10 mg PCP l −1. Three apparent PCP-degrading strains were obtained in this way and all were identified as members of the species Saccharomonospora viridis. The ability to remove PCP from liquid cultures was identified also in all five culture collection strains of S. viridis examined, and therefore appears to be a characteristic of the species. PCP removal was confirmed by gas chromatography with electron capture detection (GC–ECD) and complete removal of 10 mg PCP l −1 from shake flask cultures within 8 days was recorded for both a S. viridis isolate (3:7) and a reference strain (BD120). However, these strains were found to be unable to metabolise other chlorophenols (2-, 3-, and 4-chlorophenol; 2,4-dichlorophenol; 2,4,6-trichlorophenol and 2,3,4,6-tetrachlorophenol). PCP removal by S. viridis strains was not due to adsorption to biomass but was found to be growth dependent and required de novo protein synthesis. Neither dechlorinated intermediates nor transformation products such as chloroanisoles could be detected by GC–ECD. Furthermore, S. viridis was shown to be unable to mineralise PCP in experiments conducted with uniformly labelled 14C-PCP, in which all of the 14C was recovered from the culture supernatant. During incubation, the 14C from radiolabelled PCP became progressively less soluble in the n-hexane solvent used for GC analysis. When supernatants from S. viridis cultures grown in the presence of PCP were treated with NaOH, a compound was released which had the same GC retention time as tetrachlorohydroquinone (TCHQ), and its formation was coincident with PCP disappearance. This suggests that S. viridis metabolises PCP by conjugation to form a more polar transformation product, but unlike other PCP-degrading bacteria, is incapable of effecting total degradation of the xenobiotic. Microorganisms such as S. viridis may therefore contribute to PCP removal by microbial communities in situ, despite being unable to completely mineralise chlorophenols in pure culture

Enhanced mineralization of UL- 14C-pentachlorophenol by mushroom composts

Composting is an aerobic process which allows the rapid proliferation of a variety of microbial groups such as aerobic actinomycetes, bacilli and fungi. Waste mushroom compost is readily available as a byproduct, with 400,000-500,000 tons produced per year in the UK, and is capable of acting as a carrier for the xenobiotic-degrading microorganisms and as a nutrient source in contaminated soils. Bacteria, particularly actinomycetes, were targeted as potential PCP degraders because of their ubiquitous distribution in composts, their ability to colonize composts by mycelial growth and to degrade a wide range of aromatic compounds using either endoor extracellular enzymes (McCarthy and Williams, 1992). Semple and Fermor (1995) showed that actinomycetes, isolated from PCP-contaminated mushroom compost, were capable of attacking this highly chlorinated phenol. However, the individual putative PCP-degrading isolates tested did not achieve appreciable mineralization of UL-14C-PCP. It may be that a diverse population working in concert is required to biodegrade the chlorophenol to CO2 and H2O. However, biotransformation of PCP is a possibility given that the Saccharomonaspora viridis strains, Streptomyces spp., and Thermomonospora spp. appear to remove the PCP from the growth media (Semple and Fermor, 1995). Mineralization of PCP by composts was found to be more impressive compared to that of the actinomycete isolates. This suggests that the physical relationship between compost solid substrate and the populating microflora play an important role in the degradation of PCP. A key phenomenon to be considered when applying a bioremediative technology is chemical ageing and its relationship to bioavailability of the contaminant to the soil microflora (Hatzinger and Alexander, 1995). The longer an organic compound is in a given soil environment, the more likely it is to be affected by chemical and physical processes, such as diffusion into soil micropores, partitioning into soil organic matter, strong surface adsorption and covalent binding to soil constituents. These processes result in a decrease in the bioavailability of the compound to the degradative microorganisms, thus reducing the effectiveness of the treatment. However, it has been suggested that desorption of compounds (previously unavailable), leading to an increase in bioavailability, may occur at elevated temperatures typically generated under composting conditions (Pignatello and Xing, 1996). This will require further investigation to understand the processes involved and to characterize its effects on the degradation of PCP by mushroom composts. Le but de ce projet a été l'investigation du potentiel de biodégradation du compost utilisé pour la culture du champignon comestible Agaricus bisporus. Les composts ≪induits≫, c'est-à-dire préalablement incubés en présence de pentachlorophénol (PCP) ont minéralisé l'UL-14C-PCP en libérant du 14CO2 plus rapidement et en plus grande quantité que les composts incubés mais non induits.

Inter- and intraspecific genetic analysis of the genus Saccharomonospora with 16S to 23S ribosomal DNA (rDNA) and 23S to 5S rDNA internally transcribed spacer sequences.

In order to clarify interspecific relationships and to investigate the intraspecific phylogenetic structure of the genus Saccharomonospora, 16S to 23S ribosomal DNA (16S-23S) and 23S to 5S ribosomal DNA (23S-5S) internally transcribed spacers (ITSs) were used for sequence analyses. The 16S-23S and 23S-5S ITSs from 22 Saccharomonospora strains were amplified by PCR and directly sequenced. The average levels of nucleotide similarity of the 16S-23S and 23S-5S ITSs for the four valid species were 87.6% +/- 3.9% and 83% +/- 2.2%, respectively. For the most part, intraspecific sequence differences were not found in the two ITSs; the only exception was Saccharomonospora glauca K194, which differed from other S. glauca strains by 1 bp in the 23S-5S ITS. The Saccharomonospora viridis strains had a smaller 16S-23S ITS region than the other strains, which may be useful for differentiating these organisms from other Saccharomonospora species. The characteristics of the two ITS regions make them more useful than 16S rRNA sequences as a tool for defining and identifying Saccharomonospora strains. However, Saccharomonospora azurea K161T had two types of 23S-5S ITSs; rrnB, separated by XhoI digestion, had two additional nucleotides inserted between positions 52 and 55. Most of the 16S-23S and 23S-5S ITS sequences of S. azurea K161T and strains of "Saccharomonospora caesia" were identical; the only exception was rrnB in S. azurea K161T. The lengths and levels of sequence divergence of the two ITSs of Saccharomonospora sp. strain K180 were different from the lengths and levels of sequence divergence of the ITSs of other species. These findings suggest that a taxonomic revision of the genus Saccharomonospora is necessary. Two trees based on 16S-23S and 23S-5S ITS sequences revealed distinct interspecific relationships in the genus Saccharomonospora.

Toxicity and toxins of natural blooms and isolated strains of Microcystis spp. (Cyanobacteria) and improved procedure for purification of cultures

All samples of cyanobacterial blooms collected from 1986 to 1989 from Lake Kasumigaura, Ibaraki Prefecture, Japan, were hepatotoxic. The 50% lethal doses (LD50s) of the blooms to mice ranged from 76 to 556 mg/kg of body weight. Sixty-eight Microcystis cell clones (67 Microcystis aeruginosa and 1 M. viridis) were isolated from the blooms. Twenty-three strains (including the M. viridis strain) were toxic. However, the ratio of toxic to nontoxic strains among the blooms varied (6 to 86%). Microcystins were examined in six toxic strains. Five toxic strains produced microcystin-RR, -YR, and -LR, with RR being the dominant toxin in these strains. Another strain produced 7-desmethylmicrocystin-LR and an unknown microcystin. This strain showed the highest toxicity. Establishment of axenic strains from the Microcystis cells exhibiting extracellularly mucilaginous materials was successful by using a combination of the agar plate technique and two-step centrifugation.

Peptidoglycan of Rhodopseudomonas viridis: partial lack of N-acetyl substitution of glucosamine.

A lack of at least 70% of N-acetyl substitution of glucosamine in the glycan strands of the peptidoglycan from the gram-negative bacterium Rhodopseudomonas viridis is reported. A disaccharide, very likely GlcN beta(1 leads to 4) Mur, was observed in hydrolysates of the isolated peptidoglycan. The disaccharide was not observed when peptidoglycan was N-acetylated before hydrolysis. The peptidoglycan of R. viridis was resistant to lysozyme but became sensitive after N-acetylation with acetic anhydride. The disaccharide was found with peptidoglycan from all R. viridis strains investigated, as well as with R. sulfoviridis P1 and R. palustris strains, but not with peptidoglycan from R. gelatinosa, Rhodospirillum tenue, and Pseudomonas diminuta NCTC 8545.

The Growth and Photosynthetic Activity of Artificial Chlorophyll Mutants in Rice Plant

In artificial chlorophyll mutants (albina, xantha, viridis, striata and tigrina) of rice and their parent, a cultivar, Norin-8 (0ryza.sativa L.), several growth and photosynthetic parameters were measured and compared with each other. The following results were obtained: (1) Albina (CM-33, CM-35 and CM-53) and xantha (CM-123 and CM-213) mutants possessed no chlorophylls except for CM-123, one of xantha mutants with a small amount of chlorophyll. These mutnats including CM--123 were lethal after the fourth leaf stage. Viridis (MGS-359, MGS-859 and CMV-44) and tigrina (M-501) mutants were survival, but their dry weights and ear weights were less than their parent, normal rice plant (Norin-8). The other strains, M-516 (striata) and M-511 (viridis), showed almost normal growth patterns. (2) The chlorophyll contents of three viridis strains (MGS-359, MGS-859 and CMV-44) were about half or below of the normal type, especially deficient in chlorophyll b. The ratio of chlorophyll a to b in these viridis types was 9-20 as compared with about 3 in the normal. Also, they showed the higher levels of carotenoid than the normal plants. (3) 0n a chlorophyll basis, three viridis strains have about 1.7 to 3.0 times higher net photosynthetic rate than leaves of the normal rice. The photosynthetic rate on a leaf area basis was the same or slightly low for mutant and normal leaves. Also, the Hill reaction activities on a chlorophyll basis in the Chloroplast suspensions from mutant leaves were about 2 times of normal. The high net photosynthetic rate seems to be directly related to the lower chlorophyll contents of the mutant leaves. (4) The leaf blade in three viridis strains had a reduced thickness compared with normal plants and their spectral absorbance was below that of the normal leaves throughout the visible spectrum, especially in near 550, 600, and 650 nm