Cell wall studies on budding bacteria of the Planctomyces/Pasteuria group and on a Prosthecomicrobium sp.

Seven strains of budding, non-prosthecate bacteria belonging to the Planctomyces/Pasteuria group and a Prosthecomicrobium sp. were examined for muramic and diaminopimelic acids. These typical components of Gram-negative murein were found only in Prosthecomicrobium strain IFAM 1314, but they could not be detected in seven budding bacteria. Electron micrographs of ultrathin cell wall sections of strains IFAM 1313 and 1317 showed a membrane with bilayer structure outside the cytoplasmic membrane. 10% sodium dodecylsulfate treatment (30 min, 100°C) allowed the isolation of highly stable cell sacculi which, upon chemical analysis, proved to be mainly proteinaceous. The budding bacteria also showed considerable resistance against penicillin G, ampicillin, cephalotin and D-cycloserin. Our data indicate that these bacteria lack an ordinary Gram-negative type of murein and, instead, carry a stable protein envelope.     

Chemical composition of the peptidoglycan-free cell walls of methanogenic bacteria

Cell walls were prepared from freeze-dried samples of 7 strains of Methanobacterium by mechanical disintegration of the cells followed by incubation with trypsin. Electron microscopy revealed the presence of sacculi exhibiting the shape of the original cells, on which no surface structure could be detected. Ultrathin sections of the isolated sacculi showed a homogenously electron dense layer of about 10–15 nm in width. The ash content varied between 8 and 18% of dry weight. The sacculi of all the strains contained Lys: Ala: Glu: GlcNAc or GalNAc in a molar ratio of about 1:1.2:2:1. In one strain (M. ruminantium M 1) alanine is replaced by threonine, however. Neutral sugars and-in some strains-additional amounts of the amino sugars were present in variable amounts, and could be removed by formamide extraction or HF treatment without destroying the sacculi. No muramic acid or d-amino acids typical of peptidoglycan were found. Therefore, the sacculi of the methanobacteria consist of a different polymer containing a set of three l-amino acids and one N-acetylated amino sugar. From cells of Methanospirillum hungatii no sacculi, but tube-like sheaths could be isolated, which tend to fracture perpendicularly to the long axis of the sheath along the fibrills seen on the surface. The sheaths consist of protein containing 18 amino acids and small amounts of neutral sugars. They are resistent to the proteinases tested and are not disintegrated by boiling in 2% sodium dodecylsulfate for 30 min.The three Gram-negative strains Black Sea isolate JR-1, Cariaco isolate JR-1 and Methanobacterium mobile do not contain a rigid sacculus, but merely a SDS-sensitive surface layer composed of regularly arranged protein subunits. This evidence indicates that, within the methanogens, different cell wall polymers characteristic of particular groups of organisms may have evolved during evolution, and supports the hypothesis that the evolution of the methanogens was separated from that of the peptidoglycan-containing procaryotic organisms at a very early stage.Non Standard Abbreviations SDS sodium dodecylsulfate - EDTA ethylenediaminetetra acetic acid - DNP dinitrophenyl Dedicated to Prof. Dr. Adolf Butenandt on the occasion of his 75th birthday     

The budding bacteria,Pirellula and Planctomyces,with atypical 16S rRNA and absence of peptidoglycan,show eubacterial phospholipids and uniquely high proportions of long chain beta-hydroxy fatty acids in the lipopolysaccharide lipid A

Fatty acids of twelve strains of budding bacteria (Planctomyces and Pirellula spp.), which have atypical 16S rRNA and do not contain peptidoglycan cell walls, were shown to contain typical diacyl polar lipids with no indication of isoprenoid ether lipids suggestive of a relationship with the archaebacteria. The major ester-linked fatty acids of the phospholipids were palmitic, palmitoleic and oleic acids, which are more typical of microeukaryotes than of eubacteria. Lipopolysaccharide lipid A (LPS) was detected; it contained major proportions of long chain normal 3-OH fatty acids (3-OH eicosanoic at 23% and 17% of the total in two strains of Planctomyces, and 3-OH octadecanoic at 18%, and 3-OH palmitic at 11% of the total in one strain of Pirellula). Major portions of long chain 3-OH fatty acids in the LPS are extremely unusual and provide another atypical property of these organisms. Each strain investigated showed a specific total fatty acid composition, reflecting the diversity in 16S rRNA nucleotide catalogues.     

Enzyme activities and substrate degradation during white rot fungi growth on sugar-cane straw in a solid state fermentation

Two strains of Pleurotus spp., grown in solid state fermentation on sugar-cane straw, degraded the dry matter by 50% after 60 days. The rate of substrate consumption and the dry weight of fruiting bodies decreased in consecutive flushings. Both strains vigorously attacked hemicellulose (80% of total degradation) and lignin (70%). Fruiting bodies were rich in protein and lipids, and had a low content of carbohydrates and ash.     

Taxonomic studies on some gram-positive coryneform hydrogen bacteria

Recently isolated coryneform hydrogen bacteria were investigated under taxonomical aspects. Strains 7 C, RH 10, and 14 g are characterized by the snapping type of cell division, 68.5 to 69.7% GC content, dl-diaminopimelic acid in the cell wall, content of metachromatic granules, weak utilization of sugars and inhibitory effect of citrate. The strains are placed to the group 1—genus Corynebacterium—of the classification of coryneform bacteria of Yamada and Komagata (1972) and the name Corynebacterium autotrophicum sp.nov. is proposed.Strains 11 X and RH 12 are characterized by the bending type of cell division, a GC content of 70.2 and 70.5%, ll-diaminopimelic acid in the cell wall, absence of metachromatic granules, utilization of several sugars and no changes in cell morphology by citrate. The strains have to be placed to group 6 of coryneform bacteria.     

Thermotolerant single cell protein production byKluyveromyces marxianus var.marxianus

Summary Amino acid analyses were undertaken on single cell protein (SCP) produced by thermotolerant strains ofKluyveromyces marxianus var.marxianus grown on sugar cane molasses at 40°C. The maximum conversion of available sugars to biomass at 45°C was only 10.8% (g dry wt.·g^–1 total sugars). The amino acid composition of the SCP did not differ markedly from that reported for other yeast species.     

Assimilatory sulfur metabolism in marine microorganisms: Sulfur metabolism,protein synthesis,and growth of Pseudomonas halodurans and Alteromonas luteo-violaceus during unperturbed batch growth

Analysis of the distribution of ³⁵S-sulfate and ¹⁴C-glutamate in major biochemical components of the two marine bacteria, Pseudomonas halodurans and Alteromonas luteo-violaceus, was compared with cell density and total cellular protein during exponential growth in batch culture. For both organisms, the sulfur distribution was restricted principally to the low molecular weight organic and protein fractions, which together accounted for over 90% of the total sulfur. Carbon was more widely distributed, with these two fractions containing only 70% of the total label.Growth rate constants calculated from increases in cell numbers, protein, and ³⁵S and ¹⁴C in the various fractions indicated nearly balanced growth in A. luteo-violaceus, with constants derived from all biosynthetic parameters agreeing within 5% during the exponential phase. In contrast, protein synthesis and ³⁵S incorporation into residue protein constants were 30% higher than constants derived from cell counts and incorporation of ¹⁴C in P. halodurans. Therefore the cellular protein content P. halodurans varied over a two-fold range, with maximum protein per cell in the late exponential phase. A distinct reduction in the rate constants for total protein and ³⁵S incorporation into residue protein foreshadowed entry into the stationary phase more than one generation before other parameters.Incorporation of ³⁵S-sulfate into residue protein paralleled protein synthesis in both bacteria. The weight percent S in protein agreed well with the composition of an average protein derived from the literature. Sulfur incorporation into protein may be a useful measurement of marine bacterial protein synthesis.Abbreviations L.M.W. low molecular weight - TCA trichloroacetic acid - CFU colony forming unit     

Cell wall polysaccharides from Talaromyces species

The neutral sugars and amino sugars, released by acid hydrolysis of walls and polysaccharidic fractions, of six species of Talaromyces and the infrared spectra have been used to study their interspecific relationships. In whole cell walls neutral sugars ranged from 23 to 39.6% dry weight and were identified as glucose, galactose and mannose. Glucosamine varied from 8 to 19.8% in the samples. Galactosamine (2% or less) was found in T. emersonii and T. rotundus and no galactosamine in the other species. Sequential fractionation of the cell walls with alkali and acid gave several polysaccharidic fractions. The main differences among species were found in the alkali-soluble fraction at 20° (F1). This fraction represented 8 to 33.2% of the whole cell wall and was characterized as an -glucan in T. bacillisporus, T. emersonii, T. luteus and T. rotundus (Group A) and as a -galactofuranosyl containing glucan in T. ohiensis and T. stipitatus (Group B). The alkali-insoluble residue (F4) represented the bulk of the cell wall in all species tested (33.2% to 57.3%) and was characterized as a -glucan/chitin complex. The results may indicate degrees of interspecific relationship in the genus Talaromyces.Abbreviations CWM cell wall material - GLC gas-liquid chromatography - IR infrared - wt weight - CBS Centraal Bureau voor Schimmelcultures (Baarn. The Netherlands) - Ara arabinose - Xyl xylose - Man mannose - Gal galactose - Glc glucose - GlcNH₂ glucosamine - GalNH₂ galactosamine     

An autolysin dissolves the inner cell wall layer of the algaPediastrum (Hydrodictyaceae)

Summary An autolysin produced by young colonies ofPediastrum frees them from the vesicle in which they are formed within 12 hours of release of zoospores from the parent cell. The polysaccharide vesicle is derived from the inner wall layer of the parent cell. Refrigeration delays vesicle disintegration; boiling stops it completely. A purified, lyophilized extract of the vesicle fluid added to boiled vesicled colonies removes the vesicle in 2 hours with the release of reducing sugars and polysaccharides.Biogel P2 and P10 chromatography of the products following incubation of the enzyme preparation and wall showed no more than 1% oligosaccharides; the remaining carbohydrates had a molecular weight of several thousand daltons. Analyses of isolated vesicle wall material (70–85% of the dry weight) showed mannose accounting for approximately 50% of the dry weight, with none of the other neutral sugars present (fucose, xylose, galactose and glucose) representing more than 3%. Uronic acids account for 20–25% of the wall weight, and proteins less than 2%. Pediastrum colonies are thus freed from the vesicles in which they are formed by the action of an autolysin they produce. The autolysin acts on the vesicle wall material to generate reducing sugars and cause it to disintegrate into its constituent polysaccharides.     

The effects of Penicillium digitatum and Fusarium oxysporum rots on nutritional content of pawpaw (Carica papaya L.)

Investigations were carried out on the effects of Penicillium digitatum and Fusarium oxysporum on the nutritional value of pawpaw (Carica papaya). Decreases were observed in ash content, phosphorus, sodium, reducing sugars and ascorbic acid levels of fruits infected with P. digitatum, but increases in calcium and potassium content. In fruits infected by F. oxysporium, there were decreases in phosphorus, calcium, sodium ascorbic acid and reducing sugar levels; but the levels of ash content increased. The total protein level increased in the fruits infected with both fungi. These results revealed a reduction in fruit quality.     

A seasonal study of the red seaweeds Solieria tenera and three species of Gracilaria from Jamaica

Three species of Gracilaria viz G. cervicornis, G. domingensis, G. verrucosa and Solieria tenera (Gigartinales, Rhodophyta) have been studied for their monthly variation in dry wt yields, ash, soluble carbohydrate, protein, lipid and insoluble carbohydrate contents for one year. The dry wt yields were higher in G. domingensis. Soluble carbohydrate and ash contents showed an inverse relationship in all the species. Protein content was lower, below 5% of the dry wt for all the species. A comparison of protein:carbohydrate ratios showed a similarity between morphologically similar G. domingensis and G. cervicornis in that there was less variation in the ratio. From this, it is assumed that flattened morphology probably is more efficient in maintaining nutrient balance to keep up the growth rates.     

The DNA,RNA and protein composition of the cyanobacterium Anacystis nidulans grown in light- and carbon dioxide-limited chemostats

The DNA, RNA and protein content of the cyanobacterium Anacystis nidulans was determined in light-limited and carbon dioxide-limited chemostat cultures over the dilution rate range, D=0.02 h^-1 to 0.19 h^-1. The macromolecular contents as a percentage of the dry weight and on a per cell basis varied significantly as a function of organism growth rate and the nature of the growth conditions. For both limitations the RNA content per cell increased [20–55 fg RNA (cell)^-1] with increasing dilution rate and also showed an increase as a percentage of the dry weight. The DNA content as a percentage of the dry weight showed a 2-fold decrease with increasing dilution rate over the range examined. On a per cell basis DNA reached a peak at D=0.1 h^-1 [4.5 fg DNA (cell)^-1] for light-limited organisms and at D=0.08 h^-1 [8.0 fg DNA (cell)^-1] for carbon dioxide-limited organisms. The q _RNA increased with increasing dilution rates over the complete growth rate range examined whilst q _DNA reached a maximum at D=0.09 to 0.10 h^-1. The protein content as a percentage of the dry weight was greater in CO₂-limited organisms than light-limited organisms but in both cultures declined as the dilution rate was increased above D=0.10 h^-1.     

巨菌草根部促生菌的筛选及其促生效应

为进一步开发植物促生菌,该研究以巨菌草根部为主要材料进行巨菌草促生菌的筛选,采用解磷、固氮和产IAA等筛选标准对初筛菌株分别进行多项促生能力的测定。通过形态观察、生理生化特性和 16S rDNA序列同源性分析对促生效果最好的菌株YB-07进行分类和鉴定,分别测定其促生能力后从中筛选出促生效应强的11个菌株进行盆栽试验,并通过对这些菌株单独回接和多菌混接的小麦盆栽试验测定其对小麦的促生效应。结果表明:从巨菌草根部分离得到了101株促生菌株,分类鉴定结果显示菌株YB-07归属于根瘤菌属(Rhizobium),其溶磷量为20.1 mg·L^-1、产IAA量为23.7 mg·L^-1,同时具有产氨能力。盆栽试验测定结果显示,多菌混合接种对小麦的促生效应在株高、干重、鲜重和叶绿素含量上,分别较对照组增加了24.49%、31.84%、28.06%和34.14%。单菌接种对小麦的促生表现在株高、干重、鲜重和叶绿素含量上,分别较对照组增加了13.54%、20.45%、16.84%和35.19%。所筛选到的菌株具有良好的促生长作用,能为进一步构建巨菌草促生菌菌群提供良好的种质资源。     

Assimilatory sulfur metabolism in marine microorganisms: Sulfur metabolism,growth, and protein synthesis of Pseudomonas halodurans and Alteromonas luteo-violaceus during sulfate limitation

Sulfate concentration in the growth medium exerted a strong influence on the sulfur content of protein in two marine bacteria, Pseudomonas halodurans and Alteromonasluteo-violaceus, but the distribution of sulfur in major biochemical fractions was not affected. 90% of the total cellular sulfur was contained in low molecular weight organic compounds and protein; inorganic sulfate was not an important component. The sulfur content of isolated protein and total cellular sulfur increased in proportion to the external sulfate concentration for both bacteria, reaching a maximum at about 100–250 M. The growth rate of P. halodurans only was dependent on the sulfate concentration.Sulfur starvation of cells labeled to equilibrium with ³⁵S-sulfate resulted in a rapid decrease in low molecular weight organic S with a concommitant increase in alcohol soluble (P. halodurans) or residue protein (A. luteo-violaceus). Although cell division was prevented, total protein increased in both bacteria, resulting in synthesis of sulfur-deficient protein. This effect was most pronounced in P. halodurans.Addition of ³⁵S-sulfate to sulfur-starved A. luteo-violaceus further demonstrated that sulfur metabolism was restricted primarily to the synthesis and utilization of sulfurcontaining protein precursors. The low molecular weight organic S pool was replenished rapidly, and the pool size per cell reached twice the normal value before cell division resumed. Incorporation into protein was very rapid.Abbreviations L.M.W. low molecular weight - TCA trichloroacetic acid     

接种AMF对煤矿废弃物上高丹草的生长和叶绿素荧光的影响

为改善采矿废弃物上植被生长状况,提高植物成活率,该研究采用盆栽试验法,以高丹草为材料,选用摩西球囊霉(Glomus mosseae,G.m)和地表球囊霉(G.versiforme,G.v)两种AM真菌,分别研究单接种和混合接种对粉煤灰(S1)、煤矸石(S2)和粉煤灰与煤矸石混合物(S3)三种煤矿废弃物基质上高丹草(Sorghum bicolor×S.sudanense)生长及叶绿素荧光的影响,并以正常沙土(S4)作为对照。结果表明:(1)4种基质上,3种接种处理均获得较高侵染率,在基质S1、S3和S4上均为接种摩西球囊霉对高丹草根系侵染率最高,分别为49.04%、57.40%、43.34%,在基质S2上,混合接种处理对高丹草根系侵染效果最好,达49.33%。(2)3种煤矿废弃物基质上高丹草根长、干重、叶绿素含量、F_v/F_o、q P和Yield显著降低。接种AM真菌显著提高了高丹草的生长和光合效率。与其他处理相比,在基质S1、S3和S4上,接种摩西球囊霉显著增加了根长、干重、叶绿素含量、F_v/F_o、q P和Yield,在基质S2上,接种地表球囊霉显著增加了根长、干重,接种地表球囊霉和摩西球囊霉+地表球囊霉(G.mv)处理间叶绿素荧光参数均无显著差异。这表明在煤矿废弃物基质的复合逆境中高丹草生长和光合作用显著受到抑制,AM真菌可通过提高高丹草叶绿素含量,改善叶片叶绿素荧光和光合作用,促进植物生长,来缓解该复合逆境对高丹草造成的伤害,增强其对煤矿废弃物不良环境的抗逆性,提高煤矿区植被恢复效果。接种摩西球囊霉对粉煤灰以及粉煤灰和煤矸石混合基质上高丹草的促进作用最佳,而接种地表球囊霉更适于煤矸石基质上高丹草的生长。     

Biocontrol of <Emphasis Type="Italic">Pythium</Emphasis> damping-off in cucumber by arbuscular mycorrhiza-associated bacteria from the genus <Emphasis Type="Italic">Paenibacillus</Emphasis>

The Pythium biocontrol features of 17 Paenibacillus strains, all previously isolated from the rhizosphere, hyphosphere or bulk soil from mycorrhizal and non-mycorrhizal cucumber plants, were examined using a cucumber seedling emergence bioassay. Thirteen strains – four strains of Paenibacillus polymyxa, eight strains of P. macerans and one strain of Paenibacillus sp. – significantly increased the percentage of seedling emergence of seeds inoculated with agar plugs of Pythium aphanidermatum FC42. Overall, the efficacy of Pythium biocontrol did not seem to differ between isolates of Paenibacillus originating from either mycorrhizal or non-mycorrhizal systems. No strains significantly reduced the damping-off incidence caused by the aggressive isolate Pythium sp. B5. Two strains of P. macerans not only reduced the incidence of pre-emergence damping-off by 73%, but they also counteracted the plant growth-depressing effect of P. aphanidermatum FC42, so that 68–82% of the emerged seedlings remained healthy 7 days after sowing. Two strains of P. macerans and one strain of P. polymyxa also significantly increased the percentage of seedling emergence following inoculation with approximately 10⁵ zoospores of P. aphanidermatum FC42. There was no significant difference between the dry weight of three selected bacteria-inoculated and -uninoculated plants in the absence of Pythium; however, the dry weight of bacteria-inoculated plants was significantly higher than that of the uninoculated control plants with bacteria in the presence of P. aphanidermatum FC42.     

Molecular composition of the outer membrane of Escherichia coli and the importance of protein-lipopolysaccharide interactions

Whole cells of Escherichia coli strains 0111, K12 and B as well as the ampicillin-resistant mutant K12 D21 and several lipopolysaccharide (LPS) mutants derived from this strain were analyzed for their molar LPS content per mg dry weight. An increase of the LPS concentration in some LPS mutants was substantiated by analyzing isolated cell walls and relating the molar LPS content to the murein subunit as measure of cell surface area. The increase of LPS was paralleled by increasing amounts of phospholipid while the overall protein content in the outer membrane decreased.According to the pattern of major outer membrane proteins in the various strains and the respective LPS structures, protein-LPS interactions are discussed as important requirements for outer membrane assembly and stability.Abbreviations LPS lipopolysaccharide - SDS sodium dodecyl-sulfate Dedicated to Dr. Otto Lüderitz on the occasion of his 60th birthday     

Coinoculation of Bacillus thuringeinsis-KR1 with Rhizobium leguminosarum enhances plant growth and nodulation of pea (Pisum sativum L.) and lentil (Lens culinaris L.)

Nodulation and the subsequent nitrogen fixation are important factors that determine the productivity of legumes. The beneficial effects of nodulation can be enhanced when rhizobial inoculation is combined with plant-growth-promoting bacteria (PGPB). The PGPB strain Bacillus thuringiensis-KR1, originally isolated from the nodules of Kudzu vine (Pueraria thunbergiana), was found to promote plant growth of field pea (Pisum sativum L.) and lentil (Lens culinaris L.) under Jensen’s tube, growth pouch and non-sterile soil, respectively, when co-inoculated with Rhizobium leguminosarum-PR1. Coinoculation with B. thuringiensis-KR1 (at a cell density of 10⁶ c.f.u. ml⁻¹) provided the highest and most consistent increase in nodule number, shoot weight, root weight, and total biomass, over rhizobial inoculation alone. The enhancement in nodulation due to coinoculation was 84.6 and 73.3% in pea and lentil respectively compared to R. leguminosarum-PR1 treatment alone. The shoot dry-weight gains on coinoculation with variable cell populations of B. thuringiensis-KR1 varied from 1.04 to 1.15 times and 1.03 to 1.06 times in pea and lentil respectively, while root dry weight ratios of coinoculated treatments varied from 0.98 to 1.14 times and 1.08 to 1.33 times in pea and lentil respectively, those of R. leguminosarum-PR1 inoculated treatment at 42 days of plant growth. While cell densities higher than 10⁶ c.f.u. ml⁻¹ had an inhibitory effect on nodulation and plant growth, lower inoculum levels resulted in decreased cell recovery and plant growth performance. The results of this study indicate the potential of harnessing endophytic bacteria of wild legumes for improving the nodulation and growth of cultivated legumes.     

Isolation,identification and growth conditions of photosynthetic bacteria found in seafood processing wastewater

Four photosynthetic bacteria, isolated from 14 samples taken from seafood processing plants, were identified as species of Rhodocyclus gelatinosus, belonging to the purple, non-sulphur bacteria of the family Rhodospirillaceae. Cultivation in synthetic medium under four different conditions indicated that all four strains gave maximum carotenoid and bacteriochlorophyll synthesis under anaerobic conditions in the light, with values of 11 to 12.6 and 102 to 108 mg/g dry cell wt, respectively. These values are 87% higher than the pigment content obtained from aerobic cultivation, although the cell biomass of all strains (1.7 to 2.3 g/l) was 22 to 38% higher under aerobic conditions. Protein content was always between 32 and 43%. The specific growth rates of all isolates in aerobic cultivation (0.04 to 0.06 h^-1) were twice those in anaerobic conditions in the light. No growth occurred in anaerobic conditions in the dark.     

Biochemical analysis of four species ofCassia L. pollen

The present paper describes the comparative biochemical studies in terms of quantitative analyses of carbohydrates, lipids, proteins, free amino acids, nucleic acids, minerals, ash and moisture as well as the identification of free amino acids of pollen of four species ofCassia L. (C. alata L,C. fistula L,C. occidentalis L andC. siamea Lam.). A significant variation in the chemical constituents was observed among the four species.C. occidentalis showed the highest levels of carbohydrate (15.15%) and protein (22.45%), andC. siamea had the lowest levels of carbohydrate (7.15%), lipid (6.2%) and protein (13.85%).C. alata andC. fistula showed intermediate results. However,C. alata showed the highest amount of free amino acids (3.8%) and the least of 1.42% was found inC. fistula. Thin layer chromatography (TLC) of free amino acids of the four species showed some homology in their amino acid content, of which proline, glutamic acid, methionine and phenyl-alanine were the most dominant. The level of nucleic acids and minerals was found to be comparatively low.C. siamea andC. alata showed an exceptionally high level of ash content (8.6 and 8.8%, respectively) while moisture content varied from 8 to 11%.