Assessment of adherence to guidelines for testing and treatment of pharyngitis among children in Palestine: A retrospective review study.

Introduction: One of the most common reasons for pediatric outpatient visits is acute pharyngitis, an upper respiratory tract infection. Bacterial pharyngitis is caused by Group A beta-hemolytic Streptococcus (GABHS), also known as Streptococcus pyogenes. This research aimed to assess physicians' adherence to clinical guidelines for diagnosis, management, and selecting appropriate treatment for children suspected of bacterial pharyngitis. Methods: A retrospective, observational study was conducted by reviewing patient charts for childred aged 3 to 13 years old diagnosed with pharyngitis from June 2019 until December 2019 at the Emergency Department of Palestine Medical Complex (PMC). The Modified Centor score, throat swab collections, and assessment of antimicrobial selection were used to assess the extent of physicians' adherence to clinical guidelines for appropriate diagnosis and management of pharyngitis. SPSS was used for data analysis. Results: Out of 290 cases diagnosed with acute pharyngitis, 217 patients (74.8%) had a Modified Centor score of ≥2; 126 received antibiotics, and eight had their throat swabbed to confirm the diagnosis; furthermore, 73 patients (25.2%) had a Modified Centor score of <2; 34 of them received antibiotics. Azithromycin was the most commonly prescribed antibiotic (41.3%), followed by amoxicillin-clavulanic acid (38.1%). The frequency of empirical antibiotics prescribing was significantly higher among children with a Centor score >2, older children, and those presenting with fever. Conclusions: Most cases were not appropriately tested to confirm the diagnosis of bacterial pharyngitis and were mostly treated with inappropriate antimicrobial agents such as azithromycin. Nonadherence to clinical guidelines is very evident in this study.

In Vitro and In Silico Protocols for the Assessment of Anti-Tick Compounds from Pinus roxburghii against Rhipicephalus (Boophilus) microplus Ticks.

Pinus roxburghii, also known by the name "Himalayan chir pine," belongs to the Pinaceae family. Rhipicephalus (Boophilus) microplus tick is one of the most significant bovine ectoparasites, making it a major vector of economically important tick-borne diseases. The researchers conducted adult immersion tests (AIT) and larval packet tests (LPT) to investigate the acaricidal effect of P. roxburghii plant extract on R. (B.) microplus and its potential modulatory function when used with cypermethrin. Eggs were also assessed for their weight, egg-laying index (IE), hatchability rate, and control rate. After exposure to essential extract concentrations ranging from 2.5 to 40 mg/mL for 48 h, adult female ticks' oviposition inhibition and unfed R. (B.) microplus larvae's mortality rates were analyzed. Engorged females exposed to P. roxburghii at 40 mg/mL had reduced biological activity (oviposition, IE) compared to positive and negative controls. A concentration of 40 mg/mL of P. roxburghii caused 90% mortality in R. (B.) microplus larvae, whereas cypermethrin (the positive control) caused 98.3% mortality in LPT. In AIT, cypermethrin inhibited 81% of oviposition, compared to the 40 mg/mL concentration of P. roxburghii, which inhibited 40% of the ticks' oviposition. Moreover, this study assessed the binding capacity of selected phytocompounds with the targeted protein. Three servers (SWISS-MODEL, RoseTTAFold, and TrRosetta) recreated the target protein RmGABACl's 3D structure. The modeled 3D structure was validated using the online servers PROCHECK, ERRAT, and Prosa. Molecular docking using Auto Dock VINA predicted the binding mechanisms of 20 drug-like compounds against the target protein. Catechin and myricetin showed significant interactions with active site residues of the target protein, with docking scores of -7.7 kcal/mol and -7.6 kcal/mol, respectively. In conclusion, this study demonstrated the acaricidal activity of P. roxburghii extract, suggesting its potential as an alternative natural acaricide for controlling R. (B.) microplus.

A retrospective evaluation of drug-drug interactions in patients admitted to Internal Medicine Departments in Palestinian Hospitals.

Objective: To measure the prevalence and identify risk factors associated with drug-drug interactions among patients admitted to internal medicine departments in Palestinian hospitals. Methods: A retrospective cross-sectional observational study was conducted. Data were obtained from patient files from the internal medicine departments in Palestinian hospitals from 1 September 2017, to 31 March 2018. The data collected included patient gender, age, length of hospitalization, medications prescribed, and the number of medications. The digital clinical decision support system IBM Micromedex® was used to assess potential drug-drug interactions. Results: The number of patients included in this study is 513. The total number of potential drug-drug interactions detected in study participants is 1558. The average number of potential drug-drug interactions per patient was found to be 3 ± 3.9. Among study participants, 66.1% (n = 339) were found to have potential drug-drug interactions in their current medications. The most commonly encountered drug-drug interactions type was "major" drug-drug interaction, which was encountered in 43.6% (n = 681) of total detected drug-drug interactions. Other types of drug-drug interactions were encountered in 42% (n = 647), 14% (n = 224), and 0.4% (n = 6) which were moderate, minor, and contraindicated drug-drug interactions, respectively. Patients' age, number of medications, and length of hospitalization were associated with the increased risk of potential drug-drug interactions. Conclusion: The results indicated a high prevalence of potential drug-drug interactions in Palestinian hospitals, associated with polypharmacy, increased age, and increased length of hospitalization. Therefore, managing patient medication by a drug expert such as a clinical pharmacist to identify and resolve potential drug-drug interactions will possibly decrease the high prevalence of drug-drug interactions, prevent patient harm, and decrease the cost of hospitalization.

Novel Fusidic Acid Cream Containing Metal Ions and Natural Products against Multidrug-Resistant Bacteria.

BACKGROUND: Drug design and development to overcome antimicrobial resistance continues to be an area of research due to the evolution of microbial resistance mechanisms and the necessity for new treatments. Natural products have been used since the dawn of medicine to heal skin infections. The antimicrobial properties of fusidic acid, zinc sulfate, and copper sulfate have been studied and are well known. Furthermore, these compounds have different mechanisms of action in targeting microorganisms, either by inhibiting protein synthesis or bacterial cell walls. Therefore, their combination is expected to have synergistic activity in killing bacteria. However, the synergistic antimicrobial activity has not been evaluated in a cream formulation. Therefore, the objectives of this in vitro study were to develop and evaluate the synergistic efficacy of fusidic acid in combinations with natural products, including oleuropein, thyme oil, zinc sulfate, and copper sulfate, as a cream to eradicate fusidic-acid-resistant microorganisms in skin infections. METHODS: Three different cream formulations were developed, compared, and labeled F1, F2, and F3. The compounds were studied for their antibacterial activity. In addition, the stability of the cream was investigated at 25 °C and 40 °C in plastic jars over three months. RESULTS: The F2 formula has adequate physicochemical properties. Furthermore, it displays stable and better results than the marketed trade product and has potential inhibition zones (ZOI). Interestingly, considerable numbers (9.5%) of fusidic-acid-resistant Staphylococcus aureus (FRSA) isolates possessed a high resistance pattern with MIC ≥ 128 µg/mL. In contrast, most tested FRSA isolates (90.5%) had a low resistance pattern with MIC ≤ 8 µg/mL. CONCLUSION: In conclusion, the F2 cream made with fusidic acid, oleuropein, thyme oil, zinc sulfate, and copper sulfate in the right amounts has stable physical and chemical properties and has potential against FRSA as an antimicrobial agent.

Bacterial and fungal co-infections among ICU COVID-19 hospitalized patients in a Palestinian hospital: a retrospective cross-sectional study.

Background: Diagnosis of co-infections with multiple pathogens among hospitalized coronavirus disease 2019 (COVID-19) patients can be jointly challenging and essential for appropriate treatment, shortening hospital stays and preventing antimicrobial resistance. This study proposes to investigate the burden of bacterial and fungal co-infections outcomes on COVID-19 patients. It is a single center cross-sectional study of hospitalized COVID-19 patients at Beit-Jala hospital in Palestine. Methods: The study included 321 hospitalized patients admitted to the ICU between June 2020 and March 2021 aged ≥20 years, with a confirmed diagnosis of COVID-19 via reverse transcriptase-polymerase chain reaction assay conducted on a nasopharyngeal swab. The patient's information was gathered using graded data forms from electronic medical reports. Results: The diagnosis of bacterial and fungal infection was proved through the patient's clinical presentation and positive blood or sputum culture results. All cases had received empirical antimicrobial therapy before the intensive care unit (ICU) admission, and different regimens during the ICU stay. The rate of bacterial co-infection was 51.1%, mainly from gram-negative isolates ( Enterobacter species and K.pneumoniae). The rate of fungal co-infection caused by A.fumigatus was 48.9%, and the mortality rate was 8.1%. However, it is unclear if it had been attributed to SARS-CoV-2 or coincidental. Conclusions: Bacterial and fungal co-infection is common among COVID-19 patients at the ICU in Palestine, but it is not obvious if these cases are attributed to SARS-CoV-2 or coincidental, because little data is available to compare it with the rates of secondary infection in local ICU departments before the pandemic. Comprehensively, those conclusions present data supporting a conservative antibiotic administration for severely unwell COVID-19 infected patients. Our examination regarding the impacts of employing antifungals to manage COVID-19 patients can work as a successful reference for future COVID-19 therapy.

Bacterial and Fungal Co-Infections among ICU COVID-19 Hospitalized Patients in a Palestinian Hospital: Incidence and Antimicrobial Stewardship

Diagnosis of co-infections with multiple pathogens among hospitalized COVID-19 patients can be jointly challenging and very essential for appropriate treatment, shortening hospital stay and preventing antimicrobial resistance. This study proposes to investigate the burden of bacterial and fungal co-infections outcomes on COVID-19 patients. It is a single centre cross-sectional study of hospitalized COVID-19 patients at Beit-Jala hospital in Palestine. The study included 321 hospitalized patients admitted to the ICU between June 2020 and March 2021 aged [≥] 20 years, with a confirmed diagnosis of COVID-19 via RT-PCR conducted on a nasopharyngeal swab. The patients information was gathered using graded data forms from electronic medical reports. The diagnosis of bacterial and fungal infection was proved through the patients clinical presentation and positive blood or sputum culture results. All cases had received empirical antimicrobial therapy before the ICU admission, and different regimens during the ICU stay. The rate of bacterial co-infection was 51.1%, mainly from gram-negative isolates (Enterobacter species and K.pneumoniae). The rate of fungal co-infection caused by A.fumigatus was 48.9%, and the mortality rate was 8.1%. However, it is unclear if it had been attributed to SARS-CoV-2 or coincidental.

Explicitly correlated potential energy surface of the CH3Cl-He van der Waals complex and applications.

A new 3D-potential energy surface (3D-PES) for the weakly bound CH3Cl-He complex is mapped in Jacobi coordinates. Electronic structure calculations are performed using the explicitly correlated coupled clusters with single, double, and perturbative triple excitations approach in conjunction with the aug-cc-pVTZ basis set. Then, an analytical expansion of this 3D-PES is derived. This PES shows three minimal structures for collinear C-Cl-He arrangements and for He located in between two H atoms, in the plane parallel to the three H atoms, which is near the center of mass of CH3Cl. The latter form corresponds to the global minimum. Two maxima are also found, which connect the minimal structures. We then evaluated the pressure broadening coefficients of the spectral lines of CH3Cl in a helium bath based on our ab initio potential. Satisfactory agreement with experiments was observed, confirming the good accuracy of our 3D-PES. We also derived the bound rovibronic levels for ortho- and para-CH3Cl-He dimers after quantum treatment of the nuclear motions. For both clusters, computations show that although the ground vibrational state is located well above the intramolecular isomerization barriers, the rovibronic levels may be associated with a specific minimal structure. This can be explained by vibrational localization and vibrational memory effects.

Continuous adsorptive removal of glimepiride using multi-walled carbon nanotubes in fixed-bed column.

Water pollution by emerging pollutants such as pharmaceutical and personal care products is one of today's biggest challenges. The presence of these emerging contaminants in water has raised increasing concern due to their frequent appearance and persistence in the aquatic ecosystem and threat to health and safety. The antidiabetic drug glimepiride, GPD, is among these compounds, and it possesses adverse effects on human health if not carefully administered. Several conventional processes were proposed for the elimination of these persistent contaminants, and adsorption is among them. Therefore, in this study, the adsorptive removal of GPD from water using multi-walled carbon nanotubes (MWCNT) supported on silica was explored on a fixed-bed column. The effects of bed-height, solution pH, and flow rate on the adsorptive removal of GPD were investigated. The obtained adsorption parameters using Sips, Langmuir, and Freundlich models were used to investigate the continuous adsorption. The results showed that the drug removal is improved with the increasing bed height; however, it decreased with the flow rate. The effect of pH indicated that the adsorption is significantly affected and increased in acidic medium. The convection-dispersion model coupled with Freundlich isotherm was developed and used to describe the adsorption breakthrough curves. The maximum adsorption capacity (qm) was 275.3 mg/g, and the axial dispersion coefficients were ranged between 3.5 and 9.0 × 105 m2/s. The spent adsorbent was successfully regenerated at high pH by flushing with NaOH.

Gold with +4 oxidation state compounds: mass spectrometric and theoretical characterization of AuO2.

Using an ab initio methodology and mass spectrometric study we identify AuO2+ as a metastable species in the gas phase. This represents the first characterization of a gas phase compound of gold with the oxidation state +4. Computations show that this dication exhibits deep potential wells with long lived electronic states. Its electronic ground state is of 4∑- symmetry, which is known for very few molecular ground states. We also discussed the O + Au2+ collision dynamics, which leads mostly to charge transfer to form Au+ and O+ species. This identification may help in identifying new routes for the reactivity of gold in the gas phase, in solution and in the condensed phase.

A combined experimental and density functional theory study of metformin oxy-cracking for pharmaceutical wastewater treatment.

Pharmaceutical compounds are emerging contaminants that have been detected in surface water across the world. Because conventional wastewater treatment plants are not designed to treat such pollutants, new technologies are needed to degrade and oxidize such contaminants. The newly developed oxy-cracking process was utilized to treat the antidiabetic drug, metformin. The process, which involved partial oxidation of metformin in alkaline aqueous medium, proved to decompose the drug into small organic molecules, with minimum emission of CO2, therefore, increasing its biodegradability and removal from industrial treatment plants. The reaction gaseous products were probed by online gas chromatography. The liquid phase before and after oxy-cracking was analyzed for total carbon content by TOC and gas chromatography mass spectrometry. The products formed from the nitrogen-rich drug included ammonia, amines, amidines, and urea derivatives. A reaction mechanism for the oxy-cracking process is proposed. Because the hydroxyl radical (˙OH) is believed to play a central role in the oxy-cracking process, the mechanism is initiated by ˙OH attacks on metformin, followed by single decomposition or isomerization steps into stable products. The reactions were investigated using density functional theory calculations and validated using high quality 2nd order Møller-Plesset perturbation theory energy calculations.

Rotational (de-)excitation of isocyanogen by collision with helium at low energies.

Isocyanogen, CNCN, was discovered very recently in the interstellar medium (ISM). At present, the rate coefficients for the rotational (de-)excitation of CNCN by collisions with He are determined. First, we mapped the interaction potential between CNCN and He in Jacobi coordinates using highly correlated ab initio methodology. Then, an analytical expansion of the CNCN-He potential energy surface is derived. Later on, quantum dynamical treatments of nuclear motions are performed using the close coupling technique. We obtained the cross sections for the rotational (de-)excitation of CNCN after a collision by He up to 2000 cm-1 total energies. These cross sections are used to deduce the collision rates in the 10-300 K range. These data are needed for modeling the CNCN abundances in the ISM. This work should help for determining the abundance of such non-symmetrical dicyanopolyynes in astrophysical media and indirectly the symmetric one [Cyanogen (NCCN)].

Fixed-bed column studies of total organic carbon removal from industrial wastewater by use of diatomite decorated with polyethylenimine-functionalized pyroxene nanoparticles.

In this study, a fixed-bed column adsorption process was employed to remove organic pollutants from a real industrial wastewater effluent using polyethylenimine-functionalized pyroxene nanoparticles (PEI-PY) embedded into Diatomite at very low mass percentage. Various dynamic parameters (e.g., inlet concentration, inlet flow rate, bed height, and PEI-nanoparticle concentration in Diatomite, (%nps)) were investigated to determine the breakthrough behavior. The obtained breakthrough curves were fit with a convection-dispersion model to determine the characteristic parameters based on mass transfer phenomena. The axial dispersion coefficient (DL) and group of dimensionless numbers; including Renold number (Re), Schmidt number (Sc), and Sherwood number (Sh) were all determined and correlated by Wilson-Geankoplis correlation that was used to estimate the external film diffusion coefficients (Kc) at 0.0015 < Re<55.

Surface modification of carbon nanotubes with copper oxide nanoparticles for heat transfer enhancement of nanofluids.

Over the last few years, nanoparticles have been used as thermal enhancement agents in many heat transfer based fluids to improve the thermal conductivity of the fluids. Recently, many experiments have been carried out to prepare different types of nanofluids (NFs) showing a tremendous increase in thermal conductivity of the base fluids with the addition of a small amount of nanoparticles. However, little experimental work has been proposed to calculate the flow behaviour and heat transfer of nanofluids and the exact mechanism for the increase in effective thermal conductivity in heat exchangers. This study mainly focuses on the development of nanomaterial composites by incorporating copper oxide nanoparticles (CuO) onto the surfaces of carbon nanotubes (CNTs). The CNT-CuO nanocomposite was used to prepare water-based heat transfer NFs. The morphological surfaces and loading contents of the CNT-CuO nanocomposite were characterized using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) while the physical and thermal properties of the water-based nanofluids were characterized using differential scanning calorimetry (DSC), the Mathis TCi system and a viscosity meter for measuring the heat capacity, thermal conductivity and viscosity of the synthesized NFs, respectively. The heat transfer and the pressure drop studies of the NFs were conducted by a horizontal steel tube counter-flow heat exchanger under turbulent flow conditions. The experimental results showed that the developed NFs with different concentrations of modified CNTs (0.01, 0.05 and 0.1 wt%) have yielded a significant increase in specific heat capacity (102% higher than pure water) and thermal conductivity (26% higher than pure water) even at low concentration. The results also revealed that the heat rate of the NF was higher than that of the base liquid (water) and increased with increasing the concentration of nanoparticles. Furthermore, no significant effect of the nanoparticles on the pressure drop of the system was observed.

Skin expression of mammalian target of rapamycin and forkhead box transcription factor O1, and serum insulin-like growth factor-1 in patients with acne vulgaris and their relationship with diet.

BACKGROUND: Acne vulgaris is a multifactorial disorder of the pilosebaceous units. Several studies have reported that insulin-like growth factor (IGF)-1, forkhead box transcription factor (Fox)O1 and mammalian target of rapamycin (mTOR) interactions may be the key to understanding the links between genetic and environmental factors in acne vulgaris. OBJECTIVES: To evaluate the immunohistochemical detection of mTOR and FoxO1 in the skin, and the serum level of IGF-1 in patients with acne vulgaris. METHODS: This study was carried out on 60 participants, including 40 patients with acne and 20 controls. A diet questionnaire was administered to the patients and controls. Serum levels of IGF-1 were measured using enzyme-linked immunosorbent assay, and skin biopsies were taken from lesions on the backs of the patients and controls. FoxO1 and mTOR expression was detected using immunohistochemistry. RESULTS: A significantly higher serum IGF-1 level was found in the patients with acne than in the controls. The cytoplasmic expression of FoxO1 was found to be significantly greater in the acne group, whereas in the control subjects this expression was likely to be nuclear. Both the cytoplasmic expression and the nuclear expression of mTOR were significantly more intense in the patients with acne than in the controls. Excess consumption of a high-glycaemic-load diet was significantly associated with higher serum levels of IGF-1 and cytoplasmic expression of FoxO1 and mTOR. CONCLUSIONS: These results suggest that FoxO1, mTOR, serum IGF-1 and a high-glycaemic-load diet may play a role in acne pathogenesis.

Extensively drug-resistant Acinetobacter baumannii in a Lebanese intensive care unit: risk factors for acquisition and determination of a colonization score.

BACKGROUND: Acinetobacter baumannii (AB) has emerged as an important nosocomial pathogen causing worldwide hospital outbreaks. It has become a prototype of extensively drug-resistant (XDR) organisms. AIM: To identify risk factors for acquisition of XDR-AB and to develop a colonization risk score in intensive care unit (ICU) patients in a Lebanese tertiary care centre where XDR-AB causes intermittent outbreaks. METHODS: This retrospective study included 257 patients with baseline negative screening cultures for XDR-AB admitted to a seven-bed ICU from July 2012 to July 2013. Patients' demographic data and clinical characteristics were collected from the hospital's electronic medical records. Univariate analysis of potential risk factors was performed followed by multivariate analysis to determine parameters to be included in the colonization risk score. FINDINGS: The rate of XDR-AB acquisition was 15.6%. Multivariate analysis identified urinary catheter placement >6 days (odds ratio: 16.98; 95% confidence interval: 3.96-49.56; P<0.0001), ICU contact pressure for >4 days (2.38; 1.48-3.57; P=0.001), presence of gastrostomy tube (5.44; 1.43-20.68; P=0.013), and previous use of carbapenems or piperacillin-tazobactam (4.20; 1.65-11.81; P=0.002) as parameters to be included in the colonization score. The risk of XDR-AB acquisition was 0, 5.6%, 17.2%, 56.8%, and 80% in the presence of a score of 0, 1, 2, 3, and 4 respectively. A score of 4 indicates high probability of XDR-AB acquisition, suggesting that patient isolation is required; zero indicates a low probability of XDR-AB acquisition. CONCLUSION: Risk factors could be used to develop a score to decide which patients need isolation to limit the spread of XDR-AB.

Cytoplasmic polymorphism and evolutionary history of plum cultivars: Insights from chloroplast DNA sequence variation of trnL-trnF spacer and aggregated trnL intron & trnL-trnF spacer.

We screened for polymorphisms of the non-coding region of plastid DNA in plum trees. Sequencing data from the trnL-trnF chloroplast region were used to reveal a pattern of diversity, establish phylogenetic relationships, and test the selection pressure or evolutionary demography scenario for plastome DNA. The size of the non-coding regions varied from 398 to 563 and 865 to 1084 bases pairs for the trnL-trnF spacer and combined sequences, respectively. The average GC contents were 33.8 and 34.4% in the spacer and pooled sequences, respectively. Genetic distances calculated within the plums were 0.077 and 0.254, on average, for the trnL spacer and combined sequences, respectively. The neighbor-joining trees showed clustering relationships among cultivars that were independent of their geographic origins and designations. The neutrality tests and site-frequency spectra indicated that spacer and pooled sequences fit the neutral theory model at equilibrium between mutation and genetic drift and reject the hypothesis of a recent demographic expansion. The mismatch distribution shows variation patterns, thus providing evidence of an important genetic diversity explained by an excess of intermediate variants that occurred in the sequences analyzed. Further implications of the findings with regard to plum germplasm management and its utilization in breeding programs are also discussed.

Genetic diversity and differentiation in Prunus species (Rosaceae) using chloroplast and mitochondrial DNA CAPS markers.

Chloroplast (cpDNA) and mitochondrial DNA (mtDNA) were analyzed to establish genetic relationships among Tunisian plum cultivars using the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) technique. Two mtDNA regions (nad 1 b/c and nad 4 1/2) and a cpDNA region (trnL-trnF) were amplified and digested using restriction enzymes. Seventy and six polymorphic sites were revealed in cpDNA and mtDNA, respectively. As a consequence, cpDNA appears to be more polymorphic than mtDNA. The unweighted pair group method with arithmetic mean (UPGMA) dendrogram showed that accessions were distributed independently of their geographical origin, and introduced and local cultivars appear to be closely related. Both UPGMA and principal component analysis grouped Tunisian plum accessions into similar clusters. The analysis of the pooled sequences allowed the detection of 17 chlorotypes and 12 mitotypes. The unique haplotypes detected for cultivars are valuable for management and preservation of the plum local resources. From this study, PCR-RFLP analysis appears to be a useful approach to detect and identify cytoplasmic variation in plum trees. Our results also provide useful information for the management of genetic resources and to establish a program to improve the genetic resources available for plums.

Assessment of genetic diversity and relationships among wild and cultivated Tunisian plums (Prunus spp) using random amplified microsatellite polymorphism markers.

The usefulness of random amplified microsatellite polymorphism markers to study the genetic diversity and relationships among cultivars belonging to Prunus salicina and P. domestica and their wild relatives (P. insititia and P. spinosa) was investigated. A total of 226 of 234 bands were polymorphic (96.58%). The 226 random amplified microsatellite polymorphism markers were screened using 15 random amplified polymorphic DNA and inter-simple sequence repeat primers combinations for 54 Tunisian plum accessions. The percentage of polymorphic bands (96.58%), the resolving power of primers values (135.70), and the polymorphic information content demonstrated the efficiency of the primers used in this study. The genetic distances between accessions ranged from 0.18 to 0.79 with a mean of 0.24, suggesting a high level of genetic diversity at the intra- and interspecific levels. The unweighted pair group with arithmetic mean dendrogram and principal component analysis discriminated cultivars efficiently and illustrated relationships and divergence between spontaneous, locally cultivated, and introduced plum types. These procedures showed continuous variation that occurs independently of the status of the species and geographical origin of the plums. In this study, random amplified microsatellite polymorphism was found to be as a reliable molecular marker for fingerprinting and for examining the diversity study of the plum and its relatives.

Bacillus amyloliquefaciens strain 32a as a source of lipopeptides for biocontrol of Agrobacterium tumefaciens strains.

AIMS: A Bacillus amyloliquefaciens strain, designated 32a, was used to identify new compounds active against Agrobacterium tumefaciens and to evaluate their efficiency to control crown gall on carrot discs. METHODS AND RESULTS: Based on PCR-assays, four gene clusters were shown to direct the synthesis of the cyclic lipopeptides surfactin, iturin A, bacillomycin D and fengycin. Mass spectrometry analysis of culture supernatant led to the identification of these secondary metabolites, except bacillomycin, with heterogeneous mixture of homologues. Antimicrobial assays using lipopeptides-enriched extract showed a strong inhibitory activity against several bacterial and fungal strains, including Ag. tumefaciens. Biological control assays on carrot discs using both 32a spores and extract resulted in significant protection against crown gall disease, similar to that provided by the reference antagonistic strain Agrobacterium rhizogenes K1026. CONCLUSIONS: In contrast to all active compounds against Ag. tumefaciens that are of proteinaceous nature, this work enables for the first time to correlate the strong protective effect of B. amyloliquefaciens strain 32a towards crown gall disease with the production of a mixture of lipopeptides. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings could be useful for growers and nursery men who are particularly interested in the biocontrol of the crown gall disease.