Synthesis of bacteriochlorophyll <Emphasis Type="Italic">a</Emphasis> by the purple nonsulfur bacterium <Emphasis Type="Italic">Rhodobacter capsulatus</Emphasis>

The ability of purple nonsulfur bacteria Rhodobacter capsulatus B10 to synthesize bacteriochlorophyll under phototrophic and dark conditions was studied. The modes for cultivation in the dark with oxygen limitation in a continuous culture at D = 0.1 h^?1 were selected. The yield of biomass reached 20 g/l; the bacteriochlorophyll a output of the process amounted to 16.6 mg/l h^?1.     

Photoproduction of hydrogen by <Emphasis Type="Italic">Rhodobacter capsulatus</Emphasis> from thermophilic fermentation effluent

Rhodobacter capsulatus was used for the phototrophic hydrogen production on effluent solution derived from the thermophilic fermentation of Miscanthus hydrolysate by Thermotoga neapolitana. Pretreatments such as centrifugation, dilution, buffer addition, pH adjustment and sterilization were suggested for the effluent before being fed to the photofermentation. Batch-wise experiments showed that R. capsulatus grows and produces hydrogen on the pretreated effluent solution. Moreover, it was found that the hydrogen yield increased from 0.3 to 1.0 L/L_culture by addition of iron to the effluent solution.     

Absorbance changes accompanying the fast fluorescence induction in the purple bacterium <Emphasis Type="Italic">Rhodobacter sphaeroides</Emphasis>

The authors present a study of the fluorescence and absorbance transients occurring in whole cells of purple nonsulfur bacterium Rhodobacter sphaeroides on the millisecond timescale under pulsed actinic illumination. The fluorescence induction curve is interpreted in terms of combination of effects of redox changes in the reaction center and the membrane potential. The results of this study support the view that the membrane potential act predominantly to increase the fluorescence yield. Advantages of the pulsed actinic illumination for study of the operation of the electron transport chain in vivo are discussed.     

<Emphasis Type="Italic">In vivo</Emphasis> Proinflammatory Cytokine Production by CD-1 Mice in Response to Equipotential Doses of <Emphasis Type="Italic">Rhodobacter capsulatus</Emphasis> PG and <Emphasis Type="Italic">Salmonella enterica</Emphasis> Lipopolysaccharides

The capacities of relatively nontoxic lipopolysaccharide (LPS) from Rhodobacter capsulatus PG and highly potent LPS from Salmonella enterica serovar Typhimurium to evoke proinflammatory cytokine production have been compared in vivo. Intravenous administration of S. enterica LPS at a relatively low dose (1 mg/kg body weight) led to upregulation of TNF-α, IL-6, and IFN-γ production by non-sensitized CD-1 mice. LPS from R. capsulatus PG used at a four-times higher dose than that from S. enterica elicited production of almost the same amount of systemic TNF-α; therefore, the doses of 4 mg/kg LPS from R. capsulatus PG and 1 mg/kg LPS from S. enterica were considered to be approximately equipotential doses with respect to the LPS-dependent TNF-α production by CD-1 mice. Rhodobacter capsulatus PG LPS was a weaker inducer of the production of TNF-α, IL-6, and IFN-γ, as compared to the equipotential dose of S. enterica LPS. Administration of R. capsulatus PG LPS before S. enterica LPS decreased production of IFN-γ, but not of TNF-α and IL-6, induced by S. enterica LPS. Rhodobacter capsulatus PG LPS also suppressed IFN-γ production induced by S. enterica LPS when R. capsulatus PG LPS had been injected as little as 10 min after S. enterica LPS, but to a much lesser extent. Rhodobacter capsulatus PG LPS did not affect TNF-α and IL-6 production induced by the equipotential dose of S. enterica LPS. In order to draw conclusion on the endotoxic activity of particular LPSs, species-specific structure or arrangement of the animal or human immune systems should be considered.     

<Emphasis Type="Italic">Ty</Emphasis>1<Emphasis Type="Italic">/copia</Emphasis>- and <Emphasis Type="Italic">Ty</Emphasis>3<Emphasis Type="Italic">/gypsy</Emphasis>-like DNA sequences in <Emphasis Type="Italic">Helianthus </Emphasis>species

Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.     

Biosorption and Bioreduction of Trivalent Aurum by Photosynthetic Bacteria <Emphasis Type="Italic">Rhodobacter capsulatus</Emphasis>

Biosorption has been shown to be an eco-friendly approach to remove heavy metal ions. In this study, the photosynthetic bacteria Rhodobacter capsulatus was screened and found to have strong ability to adsorb Au(III). The maximum specific uptake of living cells was over 92.43 mg HAuCl₄/g dry weight of cell in the logarithmic phase. Biosorpion ability would be enhanced by an acidic environment. As the main cations, during biosorption the quantity of Mg²⁺ exchanged was more than Na⁺. Biosorbed Au(III) could be reduced by carotenoid and enzymes embedded and/or excreted by R. capsulatus, which might be the mechanism of photosynthtic bacteria metal tolerance.     

Revision of the <Emphasis Type="Italic">Serrulati</Emphasis> species of <Emphasis Type="Italic">Penstemon</Emphasis> section <Emphasis Type="Italic">Saccanthera</Emphasis> subsection <Emphasis Type="Italic">Serrulati</Emphasis>

A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations.     

Effect of growth conditions on electrophysical properties of <Emphasis Type="Italic">Rhodobacter capsulatus</Emphasis> PG cells

Electrophysical characteristics of cells of the phototrophic bacterium Rhodobacter capsulatus PG grown in complete Hutner medium in light or dark were found to differ depending on the composition of their lipopolysaccharides (LPS). Under dark cultivation, the cells synthesized LPS with a shortened structure that determined the electrophoretic properties of cell surfaces. The observed decrease in the effective high-frequency electroconductivity of the dark-grown cells is assumed to be due to a decrease in the intracellular K⁺ concentration resulting from increased permeability of cytoplasmic membranes of the cells grown under these conditions.     

Relations between the chemotype of <Emphasis Type="Italic">Rhodobacter capsulatus</Emphasis> strains and the cell electrophoretic properties

The cells of two Rhodobacter capsulatus strains, B10 and PG, and the LPS of their cell walls were studied by electrophysical and biochemical methods. Strain B10 was found to belong to the R chemotype, and strain PG, to the RS chemotype. A relation was revealed between the chemotype of the photosynthesizing bacteria Rhodobacter capsulatus and the electrophoretic properties of their cells.     

Antioxidant systems of moderately thermophilic methanotrophs <Emphasis Type="Italic">Methylocaldum szegediense</Emphasis> and <Emphasis Type="Italic">Methylococcus capsulatus</Emphasis>

Moderately thermophilic methanotrophs Methylocaldum szegediense O-12 and Methylococcus capsulatus Bath exhibit activities of antioxidant protection enzymes: glutathione peroxidase, superoxide dismutase, and cytochrome c peroxidase. The cells of methanotrophs grown at optimal temperatures (57 or 45°C, respectively) produce reactive oxygen species more actively than those grown at suboptimal temperatures, and exhibit higher activities of the membrane-associated cytochrome c peroxidase. Glutathione, glutathione peroxidase, and glucose-6-phosphate dehydrogenase levels in Md. szegediense O-12 increased in response to lowering of the cultivation temperature. By contrast, glutathione accumulation in cells of Mc. capsulatus Bath and the activity of glutathione peroxidase at a suboptimal temperature (29°C) were lower than at the optimal one. The role of the multilevel system of antioxidant protection in the adaptation of methanotrophs to temperature fluctuations is discussed.     

<Emphasis Type="Italic">Agrobacterium</Emphasis><Emphasis Type="Italic">tumefaciens</Emphasis>-mediated transformation of callus cells of <Emphasis Type="Italic">Crataegus</Emphasis><Emphasis Type="Italic">aronia</Emphasis>

A genetic transformation system has been developed for callus cells of Crataegus aronia using Agrobacterium tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with 5 mg l⁻¹ Indole-3-butyric acid (IBA) and 0.5 mg l⁻¹ 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red colored callus was obtained on MS medium supplemented with 2 mg l⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l⁻¹ kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l⁻¹ hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this is the first time to report an Agrobacterium-mediated transformation system in Crataegus aronia.     

Field Evidence for the Potential of <Emphasis Type="Italic">Rhodobacter capsulatus</Emphasis> as Biofertilizer for Flooded Rice

In a previous study, we evaluated the effects of inoculating rice plants with the phototrophic purple nonsulfur bacterium Rhodobacter capsulatus (Rc) on growth and yield of rice in pots and lysimeter experiments and the results obtained have been highly encouraging. In this study, we carried out two field experiments: one in the experimental farm of the Faculty of Agriculture, Fayoum University, and the second in a farmer’s field in Kafr El-sheikh, to assess the effects of Rc on growth and yield of rice in comparison and in combination with chemical nitrogen fertilizer (CNF) and farmyard manure. The results indicated that both biological and grain yields in all the Rc inoculated treatments were significantly higher than those in the uninoculated corresponding treatments in both fields. With regard to grain yield, the major factor for determining the effectiveness of any agricultural treatment, inoculation with Rc in combination with 50% of the recommended CNF rate gave a grain yield that was statistically equivalent to that obtained with 100% of the recommended CNF rate. These results provide a clear evidence for the potential of Rc as biofertilizer for flooded rice under field conditions.     

<Emphasis Type="Italic">Galleria</Emphasis><Emphasis Type="Italic">mellonella</Emphasis> are Resistant to <Emphasis Type="Italic">Pneumocystis</Emphasis><Emphasis Type="Italic">murina</Emphasis> Infection

Studying Pneumocystis has proven to be a challenge from the perspective of propagating a significant amount of the pathogen in a facile manner. The study of several fungal pathogens has been aided by the use of invertebrate model hosts. Our efforts to infect the invertebrate larvae Galleria mellonella with Pneumocystis proved futile since P. murina neither caused disease nor was able to proliferate within G. mellonella. It did, however, show that the pathogen could be rapidly cleared from the host.     

Effect of <Emphasis Type="Italic">cra</Emphasis> gene knockout together with <Emphasis Type="Italic">edd</Emphasis> and <Emphasis Type="Italic">iclR</Emphasis> genes knockout on the metabolism in <Emphasis Type="Italic">Escherichia coli</Emphasis>

To elucidate the physiological adaptation of Escherichia coli due to cra gene knockout, a total of 3,911 gene expressions were investigated by DNA microarray for continuous culture. About 50 genes were differentially regulated for the cra mutant. TCA cycle and glyoxylate shunt were down-regulated, while pentose phosphate (PP) pathway and Entner Doudoroff (ED) pathway were up-regulated in the cra mutant. The glucose uptake rate and the acetate production rate were increased with less acetate consumption for the cra mutant. To identify the genes controlled by Cra protein, the Cra recognition weight matrix from foot-printing data was developed and used to scan the whole genome. Several new Cra-binding sites were found, and some of the result was consistent with the DNA microarray data. The ED pathway was active in the cra mutant; we constructed cra.edd double genes knockout mutant to block this pathway, where the acetate overflowed due to the down-regulation of aceA,B and icd gene expressions. Then we further constructed cra.edd.iclR triple genes knockout mutant to direct the carbon flow through the glyoxylate pathway. The cra.edd.iclR mutant showed the least acetate production, resulting in the highest cell yield together with the activation of the glycolysis pathway, but the glucose consumption rate could not be improved. Dayanidhi Sarkar and Khandaker Al Zaid Siddiquee have contributed equally.     

The <Emphasis Type="Italic">Caenorhabditis</Emphasis><Emphasis Type="Italic">briggsae</Emphasis> genome contains active <Emphasis Type="Italic">CbmaT1</Emphasis> and <Emphasis Type="Italic">Tcb1</Emphasis> transposons

The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae.     

Dynamics of antagonistic potency of <Emphasis Type="Italic">Rhodobacter capsulatus</Emphasis> PG lipopolysaccharide against endotoxin-induced effects

The dynamics of antagonistic potency of lipopolysaccharide (LPS) isolated from Rhodobacter capsulatus PG on the synthesis of proinflammatory (TNF-α, IL-1β, IL-8, IL-6, IFN-γ) and antiinflammatory (IL-10, IL-1Ra) cytokines induced by highly stimulatory endotoxins from Escherichia coli or Salmonella enterica have been studied. Using human whole blood, we have shown that R. capsulatus PG LPS inhibited most pronouncedly the endotoxin-induced synthesis of TNF-α, IL-1β, IL-8, and IL-6 during the first 6 h after endotoxin challenge. Similarly, the endotoxin-induced release of IFN-γ was abolished by R. capsulatus PG LPS as well (24 h). In contrast to the above-mentioned cytokines, the relatively weak antagonistic activity of R. capsulatus PG LPS against endotoxin-triggered production of IL-6 and IL-8 was revealed. Since R. capsulatus PG LPS displays more potent antagonistic activity against deleterious effects of S. enterica LPS than those of E. coli LPS in the cases of such cytokines as IL-1β (6 and 24 h), IL-6 and IL-8 (4 h), we conclude that the effectiveness of protective action of antagonist is mostly determined by the primary lipid A structure of the employed agonist.     

New combinations and typifications in <Emphasis Type="Italic">Bistorta</Emphasis>, <Emphasis Type="Italic">Persicaria</Emphasis>, <Emphasis Type="Italic">Polygonum,</Emphasis> and <Emphasis Type="Italic">Rumex</Emphasis> (Polygonaceae)

New combinations are proposed in anticipation of the Polygonaceae treatment in the forthcoming volume of Intermountain Flora: Polygonum kelloggii var. esotericum, P. kelloggii var. watsonii , Rumex densiflorus var. pycnanthus , R. salicifolius var. utahensis, and R. occidentalis var. tomentellus. Typifications are proposed to facilitate ongoing studies in Polygonaceae and to maintain current usage.     

In planta transformation of <Emphasis Type="Italic">Notocactus scopa</Emphasis> cv. <Emphasis Type="Italic">Soonjung</Emphasis> by <Emphasis Type="Italic">Agrobacterium </Emphasis><Emphasis Type="Italic">tumefaciens</Emphasis>

Notocactus scopa cv. Soonjung was subjected to in planta Agrobacterium tumefaciens-mediated transformation with vacuum infiltration, pin-pricking, and a combination of the two methods. The pin-pricking combined with vacuum infiltration (20-30 cmHg for 15 min) resulted in a transformation efficiency of 67-100%, and the expression of the uidA and nptII genes was detected in transformed cactus. The established in planta transformation technique generated a transgenic cactus with higher transformation efficiency, shortened selection process, and stable gene expression via asexual reproduction. All of the results showed that the in planta transformation method utilized in the current study provided an efficient and time-saving procedure for the delivery of genes into the cactus genome, and that this technique can be applied to other asexually reproducing succulent plant species.