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The predatory mites Neoseiulus barkeri, Amblyseius swirskii and Cydnoseius negevi are native phytoseiid mites in Egypt. The biology of these predators was studied using Achroia grisella eggs as food source. Tested phytoseiids were succeeded to develop to adulthood and sustain oviposition on A. grisella eggs. For Cydnoseius negevi, the development was slower and fecundity was lower than for Neoseiulus barkeri and Amblyseius swirskii. The predation rate during immature stages of Cydnoseius negevi was higher than those of Neoseiulus barkeri and Amblyseius swirskii. During oviposition period, N. barkeri consumed more eggs than other phytoseiids did. The higher mean fecundity was recorded for Neoseiulus barkeri and Amblyseius swirskii as opposed to the lower mean for Cydnoseius negevi. When Amblyseius swirskii fed on Achroia grisella eggs, the oviposition period, female longevity and mean generation time were longer than for Cydnoseius negevi and Neoseiulus barkeri. Feeding on eggs of Achroia grisella resulted in the lowest mean fecundity, net reproductive rate, intrinsic rate of natural increase, finite rate of increase and gross reproductive rate for Cydnoseius negevi. The sex ratio of all predators' progeny was in female-biased. Consequently, the moth egg was alternative food for Neoseiulus barkeri and Amblyseius swirskii, while it considers as survival prey for Cydnoseius negevi.

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Authors: N. von Allmen, K. Gorzelniak, O. Liesenfeld, M. Njoya, J. Duncan, E. M. Marlowe, T. Hartel, A. Knaust, B. Hoppe and M. Walter

Rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) colonization status facilitates isolation and decolonization and reduces MRSA infections. Liquid but not dry swabs allow fully automated detection methods. However, the accuracy of culture and polymerase chain reaction (PCR) using liquid and dry swabs has not been analyzed. We compared different swab collection systems for routine nasal–throat MRSA screening in patients admitted to a tertiary care trauma center in Germany. Over 3 consecutive months, dry swabs (month 1), ESwabs (month 2), or MSwabs (month 3) were processed using Cepheid GeneXpert, Roche cobas and BD-MAX™ MRSA tests compared to chromogenic culture. Among 1680 subjects, the MRSA detection rate using PCR methods did not differ significantly between dry swabs, ESwab, and MSwab (6.0%, 6.2%, and 5.3%, respectively). Detection rates using chromogenic culture were 2.9%, 3.9%, and 1.9%, using dry, ESwab, and MSwab, respectively. Using chromogenic culture as the “gold standard”, negative predictive values for the PCR tests ranged from 99.2–100%, and positive predictive values from 33.3–54.8%. Thus, efficient and accurate MRSA screening can be achieved using dry, as well as liquid E- or MSwab, collection systems. Specimen collection using ESwab or MSwab facilitates efficient processing for chromogenic culture in full laboratory automation while also allowing molecular testing in automated PCR systems.

Open access
Authors: H. Mahmoudi, M. Salari, M. Ghayeb Zamharir and M. Ghorbani

A safflower disease was observed in the fields of South Khorasan (Iran) in 2017–2018. Affected plants had extensive fasciation, bushy growth, small leaves, phyllody and shortened internodes. Polymerase chain reaction (PCR) assays were performed using universal phytoplasma primers pairs P1/P7, R16mF1/mR1 and M1/M2 to detect putative phytoplasma (s). Nested PCR analyses showed that all symptomatic plants were positive for phytoplasma infection, while asymptomatic plants were negative. Nucleotide sequence analysis and RFLP analyses of PCR-amplified 16S rDNA sequences indicated that safflower fasciation in Iran was associated with a phytoplasma that belonged to the peanut witches' broom group (16SrII). Phylogenetic analysis confirmed that safflowers fasciation phytoplasma (SaP) must be classified in ‘Candidatus phytoplasma aurantifolia’ (16SrII) taxonomic group. To our knowledge, this is the first documentation of a phytoplasma associated with safflower fasciation in Iran and the world.

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Authors: A. Bachir, I. Selmi, A. Lehad, M. Louanchi and N. Mahfoudhi

Rugose wood disease constitutes one of the major grapevine disease complexes causing significant economic damage worldwide. It is widely distributed in all grapevine growing areas of the world and comprised of four individual syndromes, which may be caused by different viruses. These syndromes are Corky bark, LN 33 stem grooving, Kober stem grooving and Rupestris stem pitting (RSP). The present study focuses on the prevalence of three viruses associated with rugose wood complex (RWC) in Algeria.

Field inspections and collection of symptomatic samples were conducted on autumn 2012 in the table wine and autochthone accession in the western and central regions of Algeria. A total of 202 samples were tested by RT-PCR using specific primers for Grapevine virus A (GVA), Grapevine virus D (GVD) and Grapevine rupestris stem pitting associated virus (GRSPaV).

The results of RT-PCR indicated the presence of the viruses GVA, GVD and GRSPaV with 68,81% (139 out of 202 infected samples) total average infection rate. The results also indicated the predominance of GRSPaV compared to the prevalence of GVA and GVD with an infection rate of 57,92% vs. 36,63% (74 out of 202) and 2,97% (6 out of 202), respectively. Mixed infections of these three viruses were not observed in any of the samples analysed, however the mixed infection of GVA and GRSPaV was noted with a high rate of 26.73%. The grapevine cultivars; Kings Rubi, Carignan and Mersguerra were the most infected, while the Alicante Bouschet cultivar presented the lowest infection rate. To the best of our knowledge, the present study reports for the first time on the presence of GVD in Algeria.

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Authors: Hagen Frickmann, Andreas Hahn, Stefan Berlec, Johannes Ulrich, Moritz Jansson, Norbert Georg Schwarz, Philipp Warnke and Andreas Podbielski

Introduction: Escherichia coli and Staphylococcus aureus are important causes of severe diseases like blood stream infections. This study comparatively assessed potential differences in their impact on disease severity in local and systemic infections.

Methods: Over a 5-year interval, patients in whom either E. coli or S. aureus was detected in superficial or primary sterile compartments were assessed for the primary endpoint death during hospital stay and the secondary endpoints duration of hospital stay and infectious disease as the main diagnosis.

Results: Significance was achieved for the impacts as follows: Superficial infection with S. aureus was associated with an odds ratio of 0.27 regarding the risk of death and of 1.42 regarding infectious disease as main diagnosis. Superficial infection with E. coli was associated with a reduced duration of hospital stay by −2.46 days and a reduced odds ratio of infectious diseases as main diagnosis of 0.04. The hospital stay of patients with E. coli was increased due to third-generation cephalosporin and ciprofloxacin resistance, and in the case of patients with S. aureus due to tetracycline and fusidic acid resistance.

Conclusions: Reduced disease severity of superficial infections due to both E. coli and S. aureus and resistance-driven prolonged stays in hospital were confirmed, while other outcome parameters were comparable.

Open access

Abstract

In this paper, we want to support the idea of using a family of indices of similarity, that we call the Simpson's family indices or nestedness-based similarity functions (NBSF) for comparing operational geographic units (OGUs) (phytosociological relevés, animal traps, watersheds, administrative units, industrial areas, islands etc.). In these cases, similarity-dissimilarity depends, in addition to factors that induce replacement, also on factors that produce reduction or increment in the number of features within the same typology of OGUs (e.g., extent, reduction of fertility, anthropogenic pressure etc.). To keep into consideration this aspect, the indices are defined to be equal to 1 when the OGUs are completely nested. The results of the application to four simulated data sets prove that, when the data set does not show clear nested pattern, the use of NBSF produces results similar to the nestedness-free similarity functions, however since NBSF clearly detect nested situations, we should prefer their use in the circumstances where we think important to put in evidence nestedness. In conclusion, we support the idea of using both types of indices in order to improve the knowledge about the structure of any data set.

Open access

The effect of Azospirillum brasilense Sp7 (Sp7) on maize (Zea mays, Mill cv. B73) seedlings was compared when using two common carriers to deliver Sp7 to the seed: phosphate buffered saline (PBS) and magnesium sulfate (MgSO4). Seedling height, leaf chlorophyll levels, and root growth parameters were analyzed with WinRHIZO® at an early vegetative stage of plant development. Scanning and transmission electron microscope (SEM & TEM) analysis showed that carrier components do not effect bacterial binding to plant roots. MgSO4 + Sp7 caused a significant increase in the abundance of thick lateral roots, but stunted plant height, compared to other treatment groups, while relative chlorophyll contents (SPAD) significantly increased in seedlings inoculated with PBS + Sp7, revealing that the two inoculation carriers differentially affect the Sp7-associated plants.

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Authors: Muhammad Saad, Helen Mary, Umar Amjid, Ghulam Shabir, Kashif Aslam, Shahid Masood Shah and Abdul Rehman Khan

Tartary buckwheat, known for its rich source of health beneficial secondary metabolites, is cultivated in many areas of the world. Among different environmental factors, photoperiod strongly influence its growth, flowering time, and ultimately the yield. In this context, epigenetics could contribute significantly in the regulation of plant response against changing environment. Therefore, with the aim to study the involvement of DNA methylation in photoperiod mediated plant response, genome-wide DNA methylation analysis was performed in two accessions (A1 and A2) of Tartary buckwheat using three photoperiodic treatments, i.e., 10-hr light/day (T1), 12-hr light/day (T2), and 14-hr light/day (T3). Flowering time and plant fresh weight data revealed that accessions A1 and A2 prefer T1 and T2 treatments, respectively. Total DNA methylation ratio increased with the increase in photoperiod in accession A1 but decreased under same conditions in accession A2. Full methylation increased significantly while intensive decrease in hemimethylation was noted from T2 to T3 in A1, whereas full methylation strongly increased and hemimethylation strongly decreased from T1 to T2 in A2. Overall, the DNA methylation events appeared more frequently than demethylation events. This study reports for the first time an accession-/genotype specific pattern of shift in the DNA methylation under different photoperiodic treatments that will pave the way toward identification of specific genes involved in the regulation of plant response against photoperiodic stress.

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Treatment of barley grain with gibberellic acid (GA3) during malting promotes abnormal proteolysis and rapid rootlets growth affecting malt quality. This study investigated the potential of ethylene treatment as an alternative by comparing the amylase activity, total starch and total reducing sugars of germinating ‘Puma’ barley seeds treated with ethylene, 1-methylcyclopropane (1-MCP), GA3, daminozide (B-nine), GA3 + 1-MCP, ethylene + B-nine and the control after 24, 48 and 72 h from soaking. Ethylene had no effect on amylase activity. B-nine reduced amylase activity by 16 and 9.6% compared to the control after 48 and 72 h, respectively. The amylase activity of ethylene + B-nine treated seeds was higher (13.3 and 4%) than B-nine treated seeds after 48 and 72 h. This suggest that endogenous GA is important for normal amylase activity and, ethylene stimulates amylase activity where GA synthesis is inhibited. Ethylene and GA3 treatments reduced starch (83.3 mg g−1 and 76.7 mg g−1, respectively) and increased reducing sugars (16.0 and 17.1 µg ml−1, respectively) compared to the control (115.3 mg g−1 starch and 12.1 µg ml−1 reducing sugars) after 72 h. It was concluded that, ethylene may replace GA3 treatment without interfering with starch changing processes during barley malting.

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Authors: S. Kribel, S. Qostal, A. Ouazzani Touhami, K. Selmaoui, A. Mouria, R. Benkirane, El. H. Achbani and A. Douira

Thirty Trichoderma isolates isolated from compost, various crops and soil with roots of adjacent sites to the phosphate mines of Morocco, were tested in vitro for their potential to solubilize phosphorus from phosphate rock. The qualitative assessment of phosphate solubilization by Trichoderma isolates was performed on Modified Pikovskaya Agar (MPA) solid medium. The visual observation of the 3- and 6-day-old cultures did not show any clear zone around the colony. However, all the isolates were able to grow on the culture medium 3 days after incubation, the maximum recorded diameter was 58.6 mm for isolate TR-B 98 (3) and the minimum value was 34.8 mm for isolate TS-EM-98 (2). After 6 days, they showed good radial growth that exceeded 79.8 mm with variable appearance of the mycelial density such as the isolates TS-B 98, TS-EM-98 (1) and TR-CB 2000 (1) that presented, respectively, high, regular and low mycelial density. Also, the Trichoderma isolates produced variable number of conidia on MPA medium. Quantitative estimation on the Modified Pikovskaya Broth (MPB) liquid medium showed a variable potential of the Trichoderma isolates to solubilize phosphate when the amount of soluble phosphorus remained low in the liquid medium without the fungus (0.26 mgL−1). The maximum concentration of soluble phosphorus was 11.92 mgL−1 with percentage of soluble phosphorus equal to 95.39% recorded by the isolate TR-TB 2000 after 9 days of incubation, followed by the isolates TR-B 98 (3), TS-B 98 and TR-EM 2 respectively, 11.20, 10.47 and 9.61 mgL−1 and 89.6, 83.76 and 76.38%. In addition, treatments with Trichoderma isolates provided a lower final broth pH which varied between 6.81 for TOL isolate and 3.40 for TS-B-2000 (2) compared to initial pH (7.2). The isolates that proved potent for phosphate solubilization displayed the highest fresh and dry weights such as TR-TB 2000 (FW = 4.11 g and DW = 2.56 g), while the lowest fresh and dry weight were noted in the weakest isolates for phosphate solubilization such as T27 (FW = 1.025 g and DW = 0.58 g).

The high solubilization potential of Trichoderma isolates can be exploited for the solubilization of fixed phosphorus present in the soil, thus improving soil fertility and plant growth.

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