Claudio Ruggeri

Potential applications of surface active compounds by Gordonia sp. strain BS29 in soil remediation technologies.

A wide range of structurally different surface active compounds (SACs) is synthesised by many prokaryotic and eukaryotic microorganisms. Due to their properties, microbial SACs have been exploited in environmental remediation techniques. From a diesel-contaminated soil, we isolated the Gordonia sp. strain BS29 which extensively grows on aliphatic hydrocarbons and produces two different types of SACs: extracellular bioemulsans and cell-bound biosurfactants. The aim of this work was to evaluate the potential applications of the strain BS29 and its SACs in the following environmental technologies: bioremediation of soils contaminated by aliphatic and aromatic hydrocarbons, and washing of soils contaminated by crude oil, polycyclic aromatic hydrocarbons (PAHs) and heavy metals. Microcosm bioremediation experiments were carried out with soils contaminated by aliphatic hydrocarbons or PAHs, while batch soil washing experiments were carried out with soils contaminated by crude oil, PAHs or heavy metals. Bioremediation results showed that the BS29 bioemulsans are able to slightly enhance the biodegradation of recalcitrant branched hydrocarbons. On the other hand, we obtained the best results in soil washing of hydrocarbons. The BS29 bioemulsans effectively remove crude oil and PAHs from soil. Particularly, crude oil removal by BS29 bioemulsans is comparable to the rhamnolipid one in the same experimental conditions showing that the BS29 bioemulsans are promising washing agents for remediation of hydrocarbon-contaminated soils.

Chemical characterization and surface properties of a new bioemulsifier produced by Pedobacter sp. strain MCC-Z

A novel biopolymer was described in the form of an extracellular polysaccharide (EPS) by Pedobacter sp. strain MCC-Z, a member of a bacterial genus not previously described as an emulsifier producer. The new biomolecule was extracted, purified and characterized, and its surface and emulsifying properties were evaluated. The purified bioemulsifier, named Pdb-Z, showed high emulsifying activity (E24% = 64%) and reduced the surface tension of water up to 41 mN/m with a critical micelle concentration value of 2.6 mg/mL. The chemical characterization of Pdb-Z was performed using (1)H NMR, FT-IR, HPLC/MS/MS and GC/MS. Pdb-Z was found to contain 67% of carbohydrates, consisting mainly of galactose and minor quantities of talose, 30% of lipids, being pentadecanoic acid the major lipidic constituent, and 3% of proteins. The bioemulsifier was a glycolipids-protein complex with an estimated molecular mass of 10(6)Da. Furthermore, Pdb-Z emulsified pure aliphatic and aromatic hydrocarbons as well as diesel more efficiently than commercial synthetic surfactants, used for comparison. Our results suggest Pdb-Z has interesting properties for applications in remediation of hydrocarbon-contaminated environments and bioremediation processes.

Physiological and Phylogenetic Characterization of Rhodotorula diobovata DSBCA06, a Nitrophilous Yeast

Agriculture and intensive farming methods are the greatest cause of nitrogen pollution. In particular, nitrification (the conversion of ammonia to nitrate) plays a role in global climate changes, affecting the bio-availability of nitrogen in soil and contributing to eutrophication. In this paper, the Rhodotorula diobovata DSBCA06 was investigated for growth kinetics on nitrite, nitrate, or ammonia as the sole nitrogen sources (10 mM). Complete nitrite removal was observed in 48 h up to 10 mM initial nitrite. Nitrogen was almost completely assimilated as organic matter (up to 90% using higher nitrite concentrations). The strain tolerates and efficiently assimilates nitrite at concentrations (up to 20 mM) higher than those previously reported in literature for other yeasts. The best growth conditions (50 mM buffer potassium phosphate pH 7, 20 g/L glucose as the sole carbon source, and 10 mM nitrite) were determined. In the perspective of applications in inorganic nitrogen removal, other metabolic features relevant for process optimization were also evaluated, including renewable sources and heavy metal tolerance. Molasses, corn, and soybean oils were good substrates, and cadmium and lead were well tolerated. Scale-up tests also revealed promising features for large-scale applications. Overall, presented results suggest applicability of nitrogen assimilation by Rhodotorula diobovata DSBCA06 as an innovative tool for bioremediation and treatment of wastewater effluents.

Bioremediation and monitoring of seawater for the sustainable management of hydrocarbon pollution in a Tunisian Mediterranean tourist port

K pneumoniae carbapenemase – KPC producing bacteria are defined as a group of Gram-negative bacilli that is highly resistant to drugs. They cause lethal infections and illnesses. The main aim of the current study is to explore and confirm the occurrence of carbapenemase producing Klebsiella pneumonia in the ICU different compartments of an Egyptian hospital in Cairo. The study will focus in particular on the molecular class A KPC and the molecular class B MBL specifically the imipenem resistant phenotype carbapenemase (IMP) and Verona integrin-encoded metallo-beta-lactamase (VIM) producers. Isolates were collected from several compartments of the Intensive Care Unit in a private hospital in Cairo, Egypt. The screening criteria of carbapenemase producing bacteria were followed by the investigator in order to record the antimicrobial resistance patterns of all isolates. Furthermore, the modified Hodge test (MHT) was used as the instrument for detecting the carbapenemase producing isolates. Phenotypic detection of KPCs and MBLs was confirmed by the detection of blaKPC, blaIMP and blaVIM. It was also combined with disc tests in MHT positive isolates. At the end of the study, the investigators determined the compartment/s responsible for the spreading of CRKP as well as the type of the isolates occurred and how to avoid spreading and how to control it. It is worth noting that this study is considered the first report on the emergence of IMP and VIM producing Klebsiella pneumonia in the ICU compartments in Egypt. We concluded that infection control department policies in each hospital should be reinforced to evade the blowout of these bacteria in our hospitals. Also, this study should be repeated in other hospitals (especially the public hospitals) to assess the level of the problem.Background: Enterococcus faecalis normal intestinal flora of humans and one of the causes of nosocomial infections that cause urinary tract infections, endocarditis and menangeditise the ability to form biofilm on surfaces such as catheters, venous catheters artificial heart valves and ocular lenses, the ESP and cylA factors .The purpose of this study was to evaluate the ability of the bacteria in the biofilm formation and detection of virulence factors in clinical isolates of enterococci surface protein and cytolysin and Study of cyla and esp gene expression in Enterococcus faecalis culture in microfluidic conditionsH pylori infection is one of the most common infectious diseases on the globe and is associated with increased risk of human active chronic gastritis, peptic and duodenal ulcer and gastric cancer development. In order to investigate the current sero-prevalence of H. pylori infection in the Northwest part of Iran, specific ELISA for the existence of IgG antibodies against H. pylori was performed on a representative sample size of 21429 (69.02% F, 29.98% M) sera who were referred to the Central Laboratory of Tabriz in three years (2012 2015). Statistical analysis was conducted using SPSS v15.0 and Epi info v3.2.2 softwares. Results were categorized into nine groups according to the age. The overall sero-prevalence of H. pylori infection was 63.93% (63.77% F, 64.24% M), with no statistical difference between genders. Sero-positivity rates increased progressively with age but decreased above the age of 71. The results indicated that H. Pylori infection prevalence rate in the Northwest of Iran is higher than in developed countries, which may contribute to the high incident rate of gastric cancer in this area. Crowded living condition and low socio-economic status contribute to the difference of infection prevalence. Therefore, further research on H. pylori in Iran is vital to develop proactive and preventive mechanisms for gastric cancer.C is very common substance in the nature occurring mainly in cell walls of the plants. It is compact polymer consisting from glucose subunits. Due to its composition cellulose is potentially useful as a source of carbon and energy for bacterial fermentation. Unfortunately, lignocellulosic complex is generally very rigid and only a few microorganisms are able of its direct decomposition to the fermentable monosaccharides (predominantly glucose). Known, possible indirect approaches for the lignocellulosic substrate utilization are mainly their enzymatic hydrolysis to fermentable sugars or their gasification into the synthetic gas, also called syngas. The second option is to use cellulolytic microorganisms for direct utilization of cellulose to valuable product (so-called consolidated bio-processing). Unfortunately, all of these three main ways of lignocellulosic utilization have many drawbacks like too high price of process and very low product yields. Here we described system applicable for fast and specific isolation of cellulolytic mesophilic clostridium bacteria. Cellulolytic bacteria are relatively poor-described group of anaerobic bacteria which have a potential in biotechnology. For example, some of them are able to produce ethanol and some strains are secondary metabolites producers.Puccinia triticina, the causative of leaf rust, is a considerable pathogen in wheat which results in substantial amount of losses by decreasing the yield in almost all wheat growing areas of the world. Deployment of rust resistance genes into the cultivar is being used to provide resistance against the locally prevalent pathogen races as an economical, enduring and eco-friendly measure [1]. Diversity for resistance to leaf rust is available in the germplasm of related wheat genera and there are many affirmative reports which assure the effectiveness of genes originating from wild relatives of the cultivated wheat in conferring long lasting rust resistance [2]. So far more than 60 Lr genes have been identified in various wheat backgrounds [3]. Lr24 is one such resistance gene transferred into bread wheat from Agropyron elongatum which confers resistance right from the seedling stage all through the life of the plant (seedling resistance). Lr24 is being used in major wheat breeding and pyramiding programmes as a means to provide resistance to otherwise susceptible cultivars [4,5]. However, many of the seedling resistance genes when incorporated singly tend to become ineffective due the constantly evolving physiological races of the pathogen. To suppress such reviving pathogenesis, an approach to stack more than one gene into the same background has been suggested and is pursued in most of the rust resistance initiatives [6]. In this study, we have employed one such F2 population which segregates for two Lr genes. One of them is Lr24 and the other is a hypersensitive recessive adult plant resistance (APR) gene, Lr48 which confers resistance to the plant only from the time the plant reaches its booting stage and in a way decreases the selection pressure on the pathogen thus inhibiting the development of new races [2]. Differentiating the phenotypic resistance reaction of two discrete Lr genes existing in the same cultivar is practically impossible in the absence of individual Lr gene specific pathogen virulences. In such cases, the presence of exclusive DNA based markers which act as indices for each Lr gene will be valuable. Molecular markers are utilized on a huge scale to reduce cumbersomeness and enable rapid detection of specific Lr genes. Codominant molecular markers are useful in breeding programmes as only they are efficient in differentiating the heterozygous and homozygous status in plants exhibiting resistance to the pathogen infection since only the latter are significant to forward for further generations. To enable the early selection of homozygosity at the adult plant rust resistance locus, two RAPD markers S3450 and S336775 have been utilized as a co-dominant marker system [7]. The SSR marker polymorphic for Lr24 identified in our lab will be useful in wheat breeding populations and can help in fixing the genes by the F2 population level itself without any further investment till F5/F6 generations.Celiac disease (CD) is an autoimmune disorder of the small intestine that affects in genetically predisposed subjects of all age groups (from middle infancy onward CD is due to a reaction to gliadin, a prolamin (gluten protein), and similar proteins found in other crops Vis barley and rye [1]. CD symptoms include chronic diarrhea, fatigue, weight loss, weakness and classic steatorrhea. Abdominal pain, nausea and vomiting are uncommon. Most symptoms are related to malabsorption (extensive lesion in the proximal duodenum to the distal ileum produces resulting in severe malabsorption), pedal edema, protein malabsorption, easy bruising and vitamin K deficiency due to malabsorption.N Sequencing (NGS) technologies have developed progressively in microbial genomic research and clinical applications. Also, genetic fingerprinting has been used in molecular epidemiologic studies. Therefore, it is essential that a connection or a link is established between them for discovering DNA marker in whole genome for using in molecular epidemiology and bacterial diagnosis. Bioinformatics and comparative genome analysis tools lead to further and deeper understanding of genomic variation in the bacterial species. Bacterial comparative genome analyses can be used for evolutionary processes, structure and function annotations, and importantly in unique DNA marker extraction. These unique probes are suitable for high-throughput diagnostic methods such as micro-array. Finally, setting up a procedure for comparative analysis will be useful for a wide range of microbial researches and clinical applications.R B is produced by an actinobacterium Amycolatopsis mediterranei S699. Semi synthetic derivatives of rifamycin B (rifampicin or rifampin, rifabutin, rifaximine, rifapentine and rifalazil) are used for the treatment of tuberculosis (TB), leprosy and AIDS related mycobacterial infections. But none of these is effective against Multi Drug Resistant-TB (MDR-TB). This raised the need to develop novel rifamycin B analogs and corresponding derivatives to combat MDR infections. However, due to the chemical complexity of the rifamycin B further chemical modifications are not possible. An alternative approach to modify the rifamycin B backbone is combinatorial biosynthesis by manipulation of the Rifamycin Polyketide Synthase (rifPKS) gene cluster in the producer strain itself. Thus acyltransferase (AT) domain of the sixth module (AT6) of rifPKS (which adds propionate unit to the growing polyketide chain) was swapped with AT domain of the second module (AT2) of rapamycin PKS (rapPKS) (adds acetate unit) in A. mediterranei S699. The resulting mutant produced 24-desmethylrifamycin B lacking pendant methyl group at C-33 of the rifamycin skeletal structure. It was confirmed using NMR and LC-MS studies. The analog was further converted to 24-desmethylrifamycin S & 24-desmethylrifampicin that showed better antibacterial activity than rifampicin against MDR strains of M. tuberculosis. Based on this proof of concept further manipulations of other domains (AT5, AT7, AT8, DH9 & DH10) are being carried out for production of more rifamycin analogs for biological and pharmaceutical applications.