Department of Biology

Snap bean fields in 12 of the 25 governorates of Egypt were surveyed to determine the distribution and taxonomy of
snap bean-nodulating rhizobia. Nodulation rates in the field were very low, indicating that Egyptian soils do not have
sufficient numbers of snap bean-compatible Rhizobium spp. A total of 87 rhizobial isolates were assayed on the most
commonly grown cultivars in order to identify the most effective strains. The five most effective isolates (R11, R13,
R28, R49 and R52) were fast-growing and utilized a wide range of carbon and nitrogen sources. A phylogenetic
assignment of these strains by analysis of the 16S ribosomal RNA gene suggested that all fell within the Rhizobium
etli–Rhizobium leguminosarum group. Strains R11, R49 and R52 all clustered with other identified R. etli strains, while
strains R13 and R28 were more distinct. The distinctness of R13 and R28 was supported by physiological
characteristics, such as their ability to utilize citrate, erythritol, dulcitol and lactate. Strains R13 and R28 also yielded
the highest plant nitrogen content of all isolates.
The highly effective strains isolated in this study, in particular strains R13 and R28, are promising candidates for
improving crop yields. The data also suggested that these two strains represented a novel sub-group within the
R. etli–R. leguminosarum group. As snap bean is a crop of great economic value to Egypt, the identification of highly
effective rhizobial strains adapted to Egyptian soils, such as strains R13 and R28, is of great interest.
r 2009 Elsevier GmbH. All rights reserved.

Keywords: Genotypic and phenotypic characterization; Rhizobium etli; Rhizobium leguminosarum; Egypt; Snap bean (Phaseolus
vulgaris L.)

In a greenhouse experiment, two plant growth promoting rhizobacteria "PGPR" strains (Pseudomonas fluorescens FB11 and a Rhizobium leguminosarum bv. viceae FBG05) isolated from roots of faba bean plants were tested singly and in combination as seed inoculants for induction of systemic resistance in faba bean against bean yellow mosaic potyvirus (BYMV). The results demonstrated that BYMV challenged plants emerged from Pseudomonas inoculated seeds not only showed a pronounced and significant reduction in percent disease incidence (PDI) but also a significant reduction in virus concentration (ELISA) in the challenged plants, compared to the nonbacterized, challenged plants. Rhizobium singly also showed a significant reduction in both PDI and ELISA value, but the reduction was less pronounced than that resulting from Pseudomonas inoculation. Combined inoculation with Pseudomonas and Rhizobium showed no additional significant reduction in PDI or ELISA value compared with Pseudomonas singly. Appreciable and significant increase in both salicylic acid level and peroxidase activity was observed in leaves of all PGPR inoculated plants compared to other treatments. Since the PGPR inoculants (Pseudomonas and Rhizobium) and the pathogen (BYMV) remained spatially separated, it can be concluded that the tested Pseudomonas or Rhizobium strains induced systemic resistance in faba bean against BYMV. Key words: bean yellow mosaic potyvirus (BYMV), faba bean (Vicia faba L.), induced systemic resistance, Pseudomonas fluorescens, Rhizobium leguminosarum bv. viceae Zusammenfassung Zwei das Pflanzenwachstum fördernde Rhizobakterienisolate (PGPR) aus Wurzeln der Dicken Bohne, Pseudomonas fluorescens FB11 and Rhizobium leguminosarum bv. viceae FBG05, wurden einzeln und kombiniert als Saatgutbehandlungsmittel hinsichtlich einer induzierten Resistenz der Dicken Bohne gegenüber dem Bohnengelbmosaikvirus (BYMV) im Gewächshaus überprüft. Dem BYMV ausgesetzte Bohnenpflanzen zeigten nach einer Pseudomonas-Behandlung im Vergleich zur unbehandelten Kontrolle nicht nur eine deutlich verminderte Befallshäufigkeit im Bestand (BHB), sondern darüber hinaus eine signifikant verminderte Viruskonzentration im ELISA-Test. Eine Rhizobium-Behandlung des Saatguts bewirkte ebenfalls signifikant verminderte BHB-und ELISA-Werte, die allerdings unter denen Pseudomonas-behandelter Pflanzen lagen. Eine kombinierte Saatgutbehandlung mit Pseudomonas und Rhizobium übertraf die Wirkung der Pseudomonas-Einzelbehandlung nicht. Die Blätter aller PGPR-behandelten Pflanzen zeigten gegenüber der unbehandelten Kontrolle erhöhte Salicylsäurekonzentrationen und Peroxida-seaktivitäten. Die räumliche Trennung der als Saatgutbehandlungsmittel verwendeten Pseudomonas-und Rhizobium-Isolate vom Pathogen (BYMV) deutet darauf hin, dass sie in den Bohnenpflanzen eine induzierte Resistenzreaktion gegenüber dem Virus auslösten. Stichwörter: Bohnengelbmosaikvirus (BYMV), Dicke Bohne (Vicia faba L.), induzierte systemische Resistenz, Pseudomonas fluorescens, Rhizobium leguminosarum bv. viceae

ABSTRACT: Bioassay-guided separation with an
eye toward antifungal activity led to the isolation of
the new alkaloid 5-(1̀,1̀-dimethylallyl)-8-hydroxyfuro[
2-3-b] quinoline (1) and the known biscoumarin
daphnoretin (2) as the active constituents
of the chloroform extract obtained from the leaves of
Ruta chalepensis. The structures of the metabolites
were elucidated on the basis of their spectral
characteristics (NMR, UV, and MS) and were
compared with the literature. The antifungal activity
of the isolated compounds was evaluated against the
phytopathogenic fungi Rhizoctonia solani, Sclerotium
rolfsii, and Fusarium solani, which cause root-rot
and wilt diseases in several economically important
food crops such as potato, sugar beet, and tomato.

Keywords: Furoquinoline alkaloid, bis-coumarin, Ruta
chalepensis, Rutaceae, phytopathogenic fungi

The occurrence and the dynamics of phototrophic purple nonsulphur bacteria (PPNSB) as well as Azospirillum, Azotobacter, Clostridium, and cyanobacteria at dierent rice growth stages were studied in two rice®elds, at Kafr-El-Shiekh and Al-Fayoum in Egypt.

The phototrophic purple nonsulphur bacterium (PPNSB) Rhodobacter capsulatus was used to inoculate seedlings of four rice varieties Giza 159, Giza 171, Giza 176 and Giza 181, grown in hydroponic culture with or without nitrogen. After three weeks the seedling growth parameters were measured. Inoculation with R. capsulatus enhanced seedling growth of all rice varieties tested. The response to inoculation as compared to control plants (no nitrogen, no R. capsulatus) were 52% to 75% for shoot height, 47% to 100% for aerial part dry weight, 45% to 78% for aerial part N content, À37% to À 9% for maximum root length, À4% to 8% for root system dry weight and 50% to 62% for root N content.

A pot and a lysimeter experiment were carried out to study the eects of inoculation of the roots of rice seedlings with R. capsulatus in combination with graded levels of nitrogen (N) fertilizer on growth and yield of the rice variety Giza 176. Inoculation increased all the measured growth parameters and yield attributes, but the statistically signi®cant dierences at all N levels tested were only those for plant dry weight, number of productive tillers, grain and straw yields. The absolute increases in grain yield of the pot experiment due to inoculation were 0.63, 0.93 and 1.22 ton ha À1 at 0, 47.6 and 95.2 kg N ha À1 , respectively. The results suggest that inoculation along with 47.6 kg N ha À1 can save 50% of the nitrogen fertilizer needed for optimum G176 rice crop. However, inoculation along with 95.2 kg N ha À1 can increase grain yield by about 1.2 ton ha À1 . This is probably the ®rst reported evidence of a bene®cial eect of phototrophic purple nonsulphur bacteria on rice growth and yield under¯ooded soil conditions.

Ninty three PGPR isolates out of 531 rhizosphere and rhizoplane isolates of some wild plant species at Almadinah Almunawwarah, KSA were screened for the best antagonism towards plant pathogenic fungi (Fusarium oxysporum and Sclerotinia sclerotiorum ).Ten genotypes were categorized based on restriction pattern. Differentiated genotypes were subjected to molecular identification using 16S rDNA sequence analysis. The 16S-rRNA genes (~1500 bp) were amplified and about 517 bp covering up the hypervariable V3 regions (341 to 517) were sequenced. The 93 isolates were sorted into distinguished groups by amplified ribosomal DNA restriction analysis (ARDRA). Ten different profiles were obtained. Accordingly, Isolates were grouped into 10 different groups. Phylogenetic studies confirmed clustering of the 10 profiles into Bacillus, Enterobacter, and Pseudomonas clusters. Different genotypes were closely related to reference strains. However, three strains (PHP03, GIS01, and TAP02) out of the ten were regarded as a novel strains based on their low sequence similarity and high bootstrap values. Community structure analysis and distribution of these rhizobacteria showed their higher diversity in rhizoplane compared to rhizosphere.

Objective: To study in vitro antibacterial activity and physicochemical properties of three unifloral honeys (citrus, clover and cotton honeys), and to study the impacts of storage, dilution with water (33%, w/v) and autoclaving (121 °C for 15 min) on honeys characteristics. Methods: Honey samples from monofloral sources including citrus (Citrus spp.), Egyptian clover (Trifolium alexandrium) and cotton (Gossypium vitifolium) were obtained during three successive seasons (2010)(2011)(2012). Physicochemical properties and antimicrobial activities of different honey samples were studies. Results: In honey samples stored for 12 or 24 month, colour, hydroxymethyl furfural and acidity increased, while refractive index, water activity, total soluble solids, electrical conductivity and pH remained relatively unaffected, but H 2 O 2 values decreased. Types of honey exhibited various degrees of antibacterial activity against different indicator bacteria, wherein the highest antibacterial activity was recorded for clover honey followed by citrus and cotton honeys, respectively. Different species of bacteria were differed in their sensitivity to honey, wherein Salmonella enteritidis was the most sensitive followed by Staphylococcus aureus, Listeria monocytogenes and Escherichia coli, respectively. Storage up to 24 months at room temperature slightly reduced the antibacterial activity. The reduction levels were about 2.6% and 4.6% after 12 and 24 months, respectively. Diluting honeys with water increased the antibacterial activity by ca. 8.3%, while autoclaving decreased the antibacterial activity by ca. 13.5%. The relative contribution of the peroxide and non-peroxide components in the total antibacterial activity of fresh honeys was investigated. The antibacterial activity of honeys was mainly attributed to non-peroxide antibacterial agents, wherein their contribution was ca. 88%, while the contribution of H 2 O 2 was only 12%. The contribution of the thermostable antibacterial components in honey was ca. 86.8%. The antibacterial activity of the fresh clover honey was compared with the effect of 16 antibiotics on indicator bacteria. Clover honey exhibited antibacterial activity comparable to that exhibited by the tested antibiotics. Moreover, antibacterial activity of water diluted fresh clover honey was higher compared to some of tested antibiotics. Clover honey appeared to deserve further investigations, since it may prove to be a promise therapeutic honey. Conclusions: Honey samples tested in this study exhibited antibacterial activity against tested pathogenic bacteria, and this activity was mainly due to non-peroxide antibacterial factors. Clover honey appeared to deserve further investigations, since it may prove to be a promising therapeutic honey.

A novel bacteriocin-like substance produced by vaginalLactobacillus salivarius subsp. salivarius CRL 1328 with activity against Enterococcus faecalis,Enterococcus faecium, and Neisseria gonorrhoeaewas characterized. The highest level of production of this heat-resistant peptide or protein occurred during the late exponential phase. Its mode of action was shown to be bactericidal. L. salivarius subsp. salivarius CRL 1328 could be used for the design of a probiotic to prevent urogenital infections.

Objective: To study in vitro antibacterial activity and physicochemical properties of three unifloral honeys (citrus, clover and cotton honeys), and to study the impacts of storage, dilution with water (33%, w/v) and autoclaving (121 °C for 15 min) on honeys characteristics. Methods: Honey samples from monofloral sources including citrus (Citrus spp.), Egyptian clover (Trifolium alexandrium) and cotton (Gossypium vitifolium) were obtained during three successive seasons (2010-2012). Physicochemical properties and antimicrobial activities of different honey samples were studies. Results: In honey samples stored for 12 or 24 month, colour, hydroxymethyl furfural and acidity increased, while refractive index, water activity, total soluble solids, electrical conductivity and pH remained relatively unaffected, but H 2 O 2 values decreased. Types of honey exhibited various degrees of antibacterial activity against different indicator bacteria, wherein the highest antibacterial activity was recorded for clover honey followed by citrus and cotton honeys, respectively. Different species of bacteria were differed in their sensitivity to honey, wherein Salmonella enteritidis was the most sensitive followed by Staphylococcus aureus, Listeria monocytogenes and Escherichia coli, respectively. Storage up to 24 months at room temperature slightly reduced the antibacterial activity. The reduction levels were about 2.6% and 4.6% after 12 and 24 months, respectively. Diluting honeys with water increased the antibacterial activity by ca. 8.3%, while autoclaving decreased the antibacterial activity by ca. 13.5%. The relative contribution of the peroxide and non-peroxide components in the total antibacterial activity of fresh honeys was investigated. The antibacterial activity of honeys was mainly attributed to non-peroxide antibacterial agents, wherein their contribution was ca. 88%, while the contribution of H 2 O 2 was only 12%. The contribution of the thermostable antibacterial components in honey was ca. 86.8%. The antibacterial activity of the fresh clover honey was compared with the effect of 16 antibiotics on indicator bacteria. Clover honey exhibited antibacterial activity comparable to that exhibited by the tested antibiotics. Moreover, antibacterial activity of water diluted fresh clover honey was higher compared to some of tested antibiotics. Clover honey appeared to deserve further investigations, since it may prove to be a promise therapeutic honey. Conclusions: Honey samples tested in this study exhibited antibacterial activity against tested pathogenic bacteria, and this activity was mainly due to non-peroxide antibacterial factors. Clover honey appeared to deserve further investigations, since it may prove to be a promising therapeutic honey.

In a greenhouse experiment, was adapted to monitor potential of faba bean seed bacterization with R. leguminosarum for induction of systemic resistance in faba bean against Broad bean mottle virus and Botrytis fabae. The results demonstrated that BbMV or/and B. fabae challenged plants emerged from R. legumonisarum inoculated seeds not only showed a pronounced reduction in percent disease severity but also reduction in virus concentration and B. fabae count compared to the non-bacterized ones. The bioproduct efficiency to restrict the pathogenicity of BbMV and B. fabae hardly exceeded 49.85 and 77.50% with seed bacterilization respectively. In parallel with disease reductions, the faba bean plant survival was the best (average of 71.0%) when Rhizo-N was seed bacterized system. Appreciable the significant increase in both salicylic acid level, chlorophyll content, protein and peroxidase activity were recorded in leaves of all PGPR (plant growth promoting rhizobacteria) inoculated plants compared to non-bacterized ones. At harvest, the tallest of nodulated plants (45.3 cm) were those received the bioagent Rhizo-N infected faba bean host 38.5 and 35.7 cm of BYMV and B. fabae. As well as 25,15 and 14 nodules-like structures per plant on their root system, respectively. On the other hand, BbMV and B. fabae induced systemic acquired resistant in faba bean plants against pathogens. Whereas mixed infection due to reduction of BbMV (49.85%) or B. fabae (49.80%) infection. It was increased by seed bacterization with 64.30% for BbMV and B. fabae. The nodulatedfaba bean plants; BYMV and B.fabae infected ones were varied in number and density of expressed protein bands. The polymorphic (specific bands) with 52.1% polymorphism, monomorphic (commonly bands) was percentage 34.2%. and the unique band (genetic markers) was percentage 13.8% related to 1 in Rhizobium(R), BYMV(V); 2 in B. fabae(B), R+V; 3 in R+B,V+B and 4 in R+V+B with MW 70 to 14 KDa.

The role of plant growth-promoting rhizobacteria (PGPR) in adaptation of plants in extreme environments is not yet completely understood. For this study native bacteria were isolated from rhizospeheric arid soils and evaluated for both growth-promoting abilities and antagonistic potential against phytopathogenic fungi and nematodes. The phylogentic affiliation of these representative isolates was also characterized. Rhizobacteria associated with 11 wild plant species from the arid soil of Almadinah Almunawarah, Kingdom of Saudi Arabia (KSA) were investigated. From a total of 531 isolates, only 66 bacterial isolates were selected based on their ability to inhibit Fusarium oxysporum, and Sclerotinia sclerotiorum. The selected isolates were screened in vitro for activities related to plant nutrition and plant growth regulation as well as for antifungal and nematicidal traits. Isolated bacteria were found to exhibit capabilities in fix atmospheric nitrogen, produce ammonia, indoleacetic acid (IAA), siderophores, solubilize phosphate and zinc, and showed an antagonistic potential against some phytopathogenic fungi and one nematode species (Meloidogyne incognita) to various extent. Isolates were ranked by their potential ability to function as PGPR. The 66 isolates were genotyped using amplified rDNA restriction analysis (ARDRA) and 16S rRNA gene sequence analysis. The taxonomic composition of the representative genotypes from both rhizosphere and rhizoplane comprised Bacillus, Enterobacter and Pseudomonas. Out of the 10 genotypes, three strains designated as PHP03, CCP05, and TAP02 might be regarded as novel strains based on their low similarity percentages and high bootstrap values. The present study clearly identified specific traits in the isolated rhizobacteria, which make them good candidates as PGPR and might contribute to plant adaption to arid environments. Application of such results in agricultural fields may improve and enhance plant growth in arid soils.

This study was conducted to determine what effects nanoparticles (NPs) like TiO 2 , ZnO, and Ag may pose on natural attenuation processes of petroleum hydrocarbons in contaminated soils. The solid NPs used were identified using x-ray diffraction technique and their average size was certified as 18.2, 16.9, and 18.3 nm for Ag-NPs, ZnO-NPs, and TiO 2-NPs, respectively. NPs in soil microcosms behave differently where it was dissolved as in case of Ag-NPs, partially dissolved as in ZnO-NPs or changed into other crystalline phase as in TiO 2-NPs. In this investigation, catabolic gene encoding catechol 2,3 dioxygenase (C23DO) was selected specifically as biomarker for monitoring hydrocarbon biodegradation potential by measuring its transcripts by RT-qPCR. TiO 2-NPs amended microcosms showed almost no change in C23DO expression profile or bacterial community which were dominated by Bacillus sp., Mycobacterium sp., Microbacterium sp., Clostridium sp., beside uncultured bacteria, including uncultured proteobacteria, Thauera sp. and Clostridia. XRD pattern suggested that TiO 2-NPs in microcosms were changed into other noninhibitory crystalline phase, consequently, showing the maximum degradation profile for most low molecular weight oil fractions and partially for the high molecular weight ones. Increasing ZnO-NPs concentration in microcosms resulted in a reduction in the expression of C23DO with a concomitant slight deteriorative effect on bacterial populations ending up with elimination of Clostridium sp., Thauera sp., and uncultured proteobacteria. The oil-degradation efficiency was reduced compared to TiO 2-NPs amended microcosms. In microcosms, Ag-NPs were not detected in the crystalline form but were available in the ionic form that inhibited most bacterial populations and resulted in a limited degradation profile of oil, specifically the low molecular weight fractions. Ag-NPs amended microcosms showed a significant reduction (80%) in C23DO gene expression and a detrimental effect on bacterial populations including key players like Mycobacterium sp., Microbacterium sp., and Thauera sp. involved in the biodegradation of petroleum hydrocarbons.

Please cite this article as: Morsy FM et al., Dark and photofermentation H 2 production from hydrolyzed biomass of the potent extracellular polysaccharides producing cyanobacterium Nostoc commune and intracellular polysaccharide (glycogen) enriched Anabaena

Cellulosic biowastes are one of the cheapest and most abundant renewable organic materials on earth that can be, subsequent to hydrolysis, utilized as an organic carbon source for several fermentation biotechnologies. This study was devoted to explore a semidry acid hydrolysis of cellulose for decreasing the cost and ionic strength of the hydrolysate. For semidry acid hydrolysis, cellulose was just wetted with HCl (0 to 7 M) and subjected to autoclaving. The optimum molar concentration of HCl and period of autoclaving for semidry acid hydrolysis of cellulose were 6 M and 50 min respectively. Subsequent to the semidry acid hydrolysis with a minimum volume of 6 M HCl sustained by autoclaving, the hydrolysate was diluted with distilled water and neutralized with NaOH (0.5 M). The reducing sugars produced from the semidry acid hydrolysis of cellulose was further used for dark fermentation biohydrogen production by Escherichia coli as a representative of most hydrogen producing eubacteri...

The Frasassi and Acquasanta Terme cave systems in Italy host isolated lithoautotrophic ecosystems characterized by sulfur-oxidizing biofilms with up to 50% S(0) by mass. The net contributions of microbial taxa in the biofilms to production and consumption of S(0) are poorly understood and have implications for understanding the formation of geological sulfur deposits as well as the ecological niches of sulfur-oxidizing autotrophs. Filamentous Epsilonproteobacteria are among the principal biofilm architects in Frasassi and Acquasanta Terme streams, colonizing high-sulfide, low-oxygen niches relative to other major biofilm-forming populations. Metagenomic sequencing of eight biofilm samples indicated the presence of diverse and abundant Epsilonproteobacteria. Populations of Sulfurovum-like organisms were the most abundant Epsilonproteobacteria regardless of differences in biofilm morphology, temperature, or water chemistry. After assembling and binning the metagenomic data, we retriev...

Utilization of fluorescent pseudomonads bacteria (FPB) as plant growth promoting agents offers a promising alternative solution to the application of potential harmful agrochemicals. In this study, FPB inhabiting ectorhizosphere and endorhizosphere of different cultivated and wild plants species were enumerated. Rhizospheres of wild plants, in general, were found to harbor high FPB population density compared to rhizospheres of cultivated plants. From counting plates, ninety five FPB isolates representing different morphological types were obtained. The isolates were in vitro screened for activities related to plant nutrition and plant growth regulation, for antifungal traits and for antagonistic potential towards different phytopathogenic fungi. Results showed that varied proportions of the FPB isolates are putative nitrogen fixers, solubilize phosphate and zinc, produce indoleacetic acid, produce varies antifungal traits and inhibit phytopathogenic fungi. Based on the results of screening, isolates were assessed for their ability to function as plant growth promoting rhizobacteria (PGPR) and ranked. Among the top 20 FPB isolates, 8 were isolated from rhizosphere of Rotrait (Zygophyllum coccineum), 6 from Kokia (Spergularia marina L.), 3 from Akol (Alhagi graecorum, boiss), and 3 from Maize (Zea mays L.) plant.