Different Degrees Of Resistance Research Articles

Insecticide susceptibility status and knockdown resistance (kdr) mutation in Aedes albopictus in China

BackgroundAedes (Stegomyia) albopictus (Skuse, 1894) is the main vector of dengue virus in China. The resistance to insecticides is a huge obstacle for the control of this species, and determining its resistance status and mechanisms in China is essential for the implementation of vector management strategies.MethodsWe have investigated the larval and adult resistance status of Ae. albopictus to deltamethrin in eight field populations in China. Mutations at the voltage-gated sodium channel gene, related to the knockdown resistance (kdr) effect, were detected by sequencing of PCR products. The eight field populations were examined for pyrethroid resistance using the World Health Organization standard bioassays, and the association between the mutations and phenotypic resistance was tested.ResultsThe eight field populations of larvae of Ae. albopictus in China exhibited high resistance to deltamethrin; the RR50 values ranged from 12 (ZJ) to 44 (GZ). Adult bioassay revealed that Ae. albopictus populations were resistant to deltamethrin (mortality rate < 90%), except ZJ population (probably resistant, mortality rate = 93.5%). Long knockdown time in the field populations was consistent with low mortality rates in adult bioassay. F1534S mutation showed increased protection against deltamethrin in all populations except BJ and SJZ populations, whereas I1532T mutation showed increased protection against deltamethrin in only BJ population.ConclusionThere were different degrees of resistance to deltamethrin in field Ae. albopictus populations in China. The longest knockdown time and lowest mortality rate observed in Ae. albopictus population in Guangzhou indicate the severity of high resistance to deltamethrin. The patchy distribution of deltamethrin resistance and kdr mutations in Ae. albopictus mosquitoes suggests the necessity for resistance management and developing counter measures to mitigate the spread of resistance.Graphical

Identification and Validation of High LD Hotspot Genomic Regions Harboring Stem Rust Resistant Genes on 1B, 2A (Sr38), and 7B Chromosomes in Wheat.

Stem rust caused by Puccinia graminis f. sp. tritici Eriks. is an important disease of common wheat globally. The production and cultivation of genetically resistant cultivars are one of the most successful and environmentally friendly ways to protect wheat against fungal pathogens. Seedling screening and genome-wide association study (GWAS) were used to determine the genetic diversity of wheat genotypes obtained on stem rust resistance loci. At the seedling stage, the reaction of the common stem rust race QFCSC in Nebraska was measured in a set of 212 genotypes from F3:6 lines. The results indicated that 184 genotypes (86.8%) had different degrees of resistance to this common race. While 28 genotypes (13.2%) were susceptible to stem rust. A set of 11,911 single-nucleotide polymorphism (SNP) markers was used to perform GWAS which detected 84 significant marker-trait associations (MTAs) with SNPs located on chromosomes 1B, 2A, 2B, 7B and an unknown chromosome. Promising high linkage disequilibrium (LD) genomic regions were found in all chromosomes except 2B which suggested they include candidate genes controlling stem rust resistance. Highly significant LD was found among these 59 significant SNPs on chromosome 2A and 12 significant SNPs with an unknown chromosomal position. The LD analysis between SNPs located on 2A and Sr38 gene reveal high significant LD genomic regions which was previously reported. To select the most promising stem rust resistant genotypes, a new approach was suggested based on four criteria including, phenotypic selection, number of resistant allele(s), the genetic distance among the selected parents, and number of the different resistant allele(s) in the candidate crosses. As a result, 23 genotypes were considered as the most suitable parents for crossing to produce highly resistant stem rust genotypes against the QFCSC.

The implication of leaf anatomical structure for the selective breeding of lilacs.

The cultivars of the common lilac (Syringa vulgaris) grown in the south of the Russian Far East are not always winter-hardy and are often damaged by fungal diseases due to a very humid climate. A promising trend in the selective breeding of lilacs in Russia is the creation of new breeding material based on the gene pool of the broadleaf lilac (S. oblata) and its hybrids in order to introduce valuable adaptive traits into cultivars. The present work aimed to identify the traits of leaf anatomy in species and cultivars of Syringa resistant and susceptible to Pseudocercospora lilacis, the causative agent of brown leaf spot disease. The study was carried out on the living collection of the Botanical Garden-Institute, Far Eastern Branch, Russian Academy of Sciences (Vladivostok). The leaf anatomical structure of two Syringa species showing different degrees of resistance to P. lilacis in the monsoon climate of the Far East (resistant S. oblata and weakly resistant S. vulgaris, and also their hybrid cultivars) has been analyzed. The differences between species, subspecies, and cultivars are quantitative: they differ in the number of spongy mesophyll layers, the cell height in the f irst layer of palisade mesophyll, the cell height in the upper and lower epidermises, and the thickness of both mesophylls. The interspecif ic hybrids resistant or weakly resistant to P. lilacis (brown leaf spot disease) mainly retain the leaf anatomy structure of the maternal plant. One of the traits determining the resistance of hybrid lilac cultivars is an increased number of spongy mesophyll layers in the leaf blade. The study of leaf anatomy has shown that the four-layered spongy mesophyll leaf parenchyma correlates with the resistance of lilacs from the subsection Euvulgaris to P. lilacis. In S. oblata, this trait is inherited down the maternal line. To establish lilac cultivars resistant to fungal diseases, it is advisable to cross the two species (S. oblata and S. vulgaris) or their cultivars using one of S. oblata subspecies as a maternal plant.

Root morphological traits of oil palm genotypes with differential resistance to fatal yellowing

Brazil has an extensive area where the climate and soil are suitable for oil palm growing. However, in part of this area, production has been limited by the occurrence of the fatal yellowing (FY) anomaly, whose initial symptom is the rotting of absorptive roots. This symptom can be more severe in oil palm genetic materials with a smaller root system. The aim of this study was to examine morphological traits of roots and shoots of seedlings of three oil palm genotypes with different degrees of resistance to FY, namely, Tenera (sensitive), Caiaué (resistant) and Interspecific Hybrid (resistant) to provide bases to elucidate the differential resistance of these materials to FY. Shoot biomass did not vary statistically between the genetic materials. The mass, length and area of fine and very fine roots were significantly higher in the Interspecific Hybrid than in Caiaué and Tenera. The fine and very fine roots of Interspecific Hybrid had a larger mass than Caiaué (114 and 133%, respectively) and Tenera (216 and 178%, respectively). The Interspecific Hybrid also exhibited higher values for the length of fine and very fine roots than Caiaué (155 and 99% respectively) and Tenera (228 and 94% respectively). The root traits of the Interspecific Hybrid and Tenera are compatible with their differential resistance to FY. Our results demonstrate the importance of expanding the study of the relationship between root morphology and resistance to FY in these genetic materials under conditions that favor the occurrence of the anomaly, such as flooding.

Evaluation of heavy metal content in water and removal of metals using native isolated bacterial strains

Abstract. Saleh LIF, Rashed RO, Muhammed SM. 2021. Evaluation of heavy metal content in water and removal of metals using native isolated bacterial strains. Biodiversitas 22: 3163-3174. Natural surface water sources are susceptible to chemical contamination, including heavy metals. The goals of this study were to isolate naturally occurring heavy metal-tolerant bacteria by evaluating their ability to remove heavy metals from Tanjaro River and assessing the river’s water quality. The potency of bacteria to remove heavy metals (Cd, Pb, Cu, Cr, Ni, Zn, Co, and Fe) from the medium was conducted by inductively coupled plasma-optical emission spectrometry. Results of physicochemical parameters of the water samples were as follows: temperature 11.9–31°C, pH 6.1–8.64, total dissolved solids 268–464 mg.l-1, total hardness 232–485 mg.l-1, and alkalinity 122–324.3 mg.l-1. The overall mean concentrations of the heavy metals were in the order of Zn &gt;Cu&gt; Pb&gt; Ni&gt; Co&gt; Fe&gt; Cr&gt; Cd), with values of 0.086, 0.073, 0.71, 0.068, 0.051, 0.056, 0.031, and 0.024ppm, respectively Moreover, the concentrations were generally exceeded the water quality criteria of WHO in some observations. The isolates included both gram-negative (56.5%) and gram-positive (43.5%) bacteria. The isolates displayed different degrees of resistance to heavy metals with maximum tolerable concentrations (MTCs) ranging from (10-250) ppm. Bacillus safensis and Leucobacter chromiiresistens were respectively able to tolerate (80, 90 ppm) Cd, (250, 160 ppm) Pb, (210,100 ppm) Cr, (110, 90 ppm) Ni and (160, 170 ppm) Co, while, Proteus mirabilis could tolerate 90 ppm Cd. The isolates were able to remove 55.4%Pb, 53.1%Cr, 53.7%Ni, 47.7Fe, 61.4%Co, and 55.8% Cu from a medium supplemented with the mixture of these heavy metals. The finding of this study indicated that Tanjaro River was undergoing frequent changes in water quality. Native bacterial isolates possessed considerable tolerance to selected heavy metals, which provides promising candidates for use in bioremediation.

Mono-Locus and Pyramided Resistant Grapevine Cultivars Reveal Early Putative Biomarkers Upon Artificial Inoculation With Plasmopara viticola

One of the most economically important grapevine diseases is Downy mildew (DM) caused by the oomycete Plasmopara viticola. A strategy to reduce the use of fungicides to compensate for the high susceptibility of V. vinifera is the selection of grapevine varieties showing pathogen-specific resistance. We applied a metabolomics approach to evaluate the metabolic modulation in mono-locus resistant genotypes carrying one locus associated with P. viticola resistance (Rpv) (BC4- Rpv1, Bianca- Rpv3-1, F12P160- Rpv12, Solaris- Rpv10), as well as in pyramided resistant genotypes carrying more than one Rpv (F12P60- Rpv3-1; Rpv12 and F12P127- Rpv3-1, Rpv3-3; Rpv10) taking as a reference the susceptible genotype Pinot Noir. In order to understand if different sources of resistance are associated with different degrees of resistance and, implicitly, with different responses to the pathogen, we considered the most important classes of plant metabolite primary compounds, lipids, phenols and volatile organic compounds at 0, 12, 48, and 96 h post-artificial inoculation (hpi). We identified 264 modulated compounds; among these, 22 metabolites were found accumulated in significant quantities in the resistant cultivars compared to Pinot Noir. In mono-locus genotypes, the highest modulation of the metabolites was noticed at 48 and 96 hpi, except for Solaris, that showed a behavior similar to the pyramided genotypes in which the changes started to occur as early as 12 hpi. Bianca, Solaris and F12P60 showed the highest number of interesting compounds accumulated after the artificial infection and with a putative effect against the pathogen. In contrast, Pinot Noir showed a less effective defense response in containing DM growth.

The Fusarium oxysporum f. sp. niveum: Causal Agent of Vascular Withering of Watermelon

Objective: To describe Fusarium oxysporum f. sp. niveum (Fon) as the causal agent of vascular withering in the watermelon crop (Citrullus lanatus (Thunb.) Matsum and Nakai). Design/Methodology/Approach: A review of scientific literature (scientific books, notes and articles) was carried out about Fon as the causal agent of vascular withering in the watermelon crop; biology, symptoms, disease cycle, isolation and management alternatives. Results: Withering from Fusarium in watermelon is the main fungal disease of this crop worldwide. Necrosis of the vascular tissue and withering of the plant are the most characteristic symptoms of the disease. There are four races of this fungus (Fon race 0, 1, 2 and 3); the commercial varieties of watermelons have different degrees of resistance to these races. Practices such as the correct diagnosis, use of grafts, solarization, fungicides, biological products and genetic resistance can significantly reduce the impact of the disease on the production. Findings/Conclusions: In Mexico, knowledge about vascular withering of watermelon is scarce despite this disease being one of the factors that limits commercial production. The greatest knowledge about the symptoms, the fungus’s biology, presence and distribution of races, diagnosis and alternatives of Fon management, will allow integrating appropriate management practices that favor the commercial production of the crop.

Rabbit PrP Is Partially Resistant to in vitro Aggregation Induced by Different Biological Cofactors.

Prion diseases have been described in humans and other mammals, including sheep, goats, cattle, and deer. Since mice, hamsters, and cats are susceptible to prion infection, they are often used to study the mechanisms of prion infection and conversion. Mammals, such as horses and dogs, however, do not naturally contract the disease and are resistant to infection, while others, like rabbits, have exhibited low susceptibility. Infection involves the conversion of the cellular prion protein (PrPC) to the scrapie form (PrPSc), and several cofactors have already been identified as important adjuvants in this process, such as glycosaminoglycans (GAGs), lipids, and nucleic acids. The molecular mechanisms that determine transmissibility between species remain unclear, as well as the barriers to transmission. In this study, we examine the interaction of recombinant rabbit PrPC (RaPrP) with different biological cofactors such as GAGs (heparin and dermatan sulfate), phosphatidic acid, and DNA oligonucleotides (A1 and D67) to evaluate the importance of these cofactors in modulating the aggregation of rabbit PrP and explain the animal’s different degrees of resistance to infection. We used spectroscopic and chromatographic approaches to evaluate the interaction with cofactors and their effect on RaPrP aggregation, which we compared with murine PrP (MuPrP). Our data show that all cofactors induce RaPrP aggregation and exhibit pH dependence. However, RaPrP aggregated to a lesser extent than MuPrP in the presence of any of the cofactors tested. The binding affinity with cofactors does not correlate with these low levels of aggregation, suggesting that the latter are related to the stability of PrP at acidic pH. The absence of the N-terminus affected the interaction with cofactors, influencing the efficiency of aggregation. These findings demonstrate that the interaction with polyanionic cofactors is related to rabbit PrP being less susceptible to aggregation in vitro and that the N-terminal domain is important to the efficiency of conversion, increasing the interaction with cofactors. The decreased effect of cofactors in rabbit PrP likely explains its lower propensity to prion conversion.

Enhancement of innate and adaptive anti-tumor immunity by serum obtained from vascular photodynamic therapy-cured BALB/c mouse.

Photodynamic therapy (PDT) is a clinically approved treatment for various types of cancer. Besides killing the tumor cells directly, PDT has also been reported to trigger anti-tumor immunity. In our previous study, BAM-SiPc-based PDT was shown to induce immunogenic cell death on CT26 murine colon tumor cells in vitro. Using the BALB/c mouse animal model and a vascular-PDT (VPDT) approach, it could also eradicate tumor in ∼ 70% of tumor-bearing mice and elicit an anti-tumor immune response. In the present study, the serum obtained from the VPDT-cured mice was studied and found to possess various immunomodulatory properties. In in vitro studies, it stimulated cytokine secretions of IL-6 and C-X-C motif chemokine ligands 1-3 in CT26 cells through the NF-κB and MAPK pathways. The complement protein C5a boosted in the serum was shown to be involved in the process. The serum also induced calreticulin exposure on CT26 cells and activated dendritic cells. It contained CT26-targeting antibodies which, through the Fc region, induced macrophage engulfment of the tumor cells. In in vivo studies, inoculation of the serum-treated CT26 cells to mice demonstrated a retarded tumor growth with leukocytes, particularly T cells, attracted to the tumor site. In addition, the VPDT-cured mice showed different degrees of resistance against challenge of other types of murine tumor cells, for example, the breast tumor 4T1 and EMT6 cells.

Raman spectroscopy reveals alteration of spore compositions under different nutritional conditions in Lysinibacillus boronitolerans YS11.

Little is known about final spores components when bacteria undergo sporulation under different nutrient conditions. Different degrees of resistance and germination rates were observed in the three types of spores of Lysinibacillus boronitolerans YS11 (SD, Spores formed in Difco sporulation medium™; SC and SF, Spores formed in an agricultural byproduct medium with 10 mM CaCl2 and with 10 mM FeSO4, respectively). Stronger UV resistance was recorded for SF with 1.8-2.3-fold greater survival than SC and SD under UV treatment. The three spore types showed similar heat resistances at 80°C, but survival rates of SC and SD were much higher (∼1,000 times) than those of SF at 90°C. However, germination capacity of SF was 20% higher than those of SD and SC on Luria-Bertani agar plates for 24 h. SF germinated more rapidly in a liquid medium with high NaCl concentrations than SC and SD, but became slower under alkaline conditions. Raman spectroscopy was used to analyze the heterogeneities in the three types of vegetative cells and their spores under different nutritional conditions. Exponentially grown-each vegetative cells had different overall Raman peak values. Raman peaks of SC, SD, and SF also showed differences in adenine and amide III compositions and nucleic acid contents. Our data along with Raman spectroscopy provided the evidence that spores formed under under different growth conditions possess very different cellular components, which affected their survival and germination rates.

Cationic tetra- and pentacoordinate complexes of nickel based on POCN- and POCOP-type pincer ligands: synthesis, characterization, and ligand exchange studies

The closely related pincer ligands POCN and POCOP display different electron donating properties and different degrees of resistance to ligand exchange reactions proceeding via cationic reaction intermediates.

Study on the expression of Nbs-lrr gene analogue (nbs552) in Citrus species infected with ‘candidatus liberibacter asiaticus’ and phytoplasmas

Candidatus Liberibacter asiaticus’ is associated with “huanglongbing” disease in citrus; however the various cultivars/genotypes combinations show a different degree of resistance. Recently, an NBS-LRR resistance transcript (NBS552) has been identified in grapefruit and pomelo trees infected by Ca. L. asiaticus’ under greenhouse conditions, therefore the expression level of this gene in severely HLB-infected orchards was studied in 1,170 symptomatic and asymptomatic trees. The total DNA was extracted from leaf midrib tissues and PCR with the primer set OI1/OI2c was performed to detect Ca. Liberibacter’ species presence. Two phytoplasma universal primer sets were employed to verify the presence of phytoplasmas in the same plants. PCR assays were then carried out to detect the NBS552 gene presence in the collected samples and its expression was analyzed using quantitative RT-PCR and resulted different between Ca. Liberibacter’ species- and phytoplasma-infected citrus plants. These results could confirm that phytoplasma presence is decreasing the NBS552 expression level therefore the expression of this gene may be used for further studies on citrus susceptibility to phloem-restricted prokaryotes.

The occurrence of herbicide-resistant Avena fatua (wild oats) populations to ACCase-inhibiting herbicides in Ireland

Following growers’ reports of herbicide control problems, populations of 30 wild oats, Avena fatua, were collected from the south-east main arable counties of Ireland in 2016 and investigated for the occurrence and potential for herbicide resistance to acetyl-CoA carboxylase (ACCase) inhibitors pinoxaden, propaquizafop and cycloxydim, as well as acetolactate synthase (ALS) inhibitor mesosulfuron + iodosulfuron. Plant survival ≥20% was considered as the discriminating threshold between resistant and susceptible populations, when plants were treated with full recommended field rates of ACCase/ALS inhibitors. Glasshouse sensitivity screens revealed 2 out of 30 populations were cross-resistant to all three ACCase inhibitors. While three populations were cross-resistant to both pinoxaden and propaquizafop, and additionally, two populations were resistant to propaquizafop only. Different degree of resistance and cross-resistance between resistant populations suggest the involvement of either different point mutations or more than one resistance mechanism. Nevertheless, all populations including the seven ACCase-resistant populations were equally susceptible to ALS inhibitor. An integrated weed management (cultural/non-chemical control tactics and judicious use of herbicides) approach is strongly recommended to minimize the risk of herbicide resistance evolution.

Insight into the drug resistance mechanisms of GS-9669 caused by mutations of HCV NS5B polymerase via molecular simulation

GS-9669 is a non-nucleos(t)ide inhibitor (NNI) binding to the thumb site II of the Hepatitis C virus (HCV) NS5B polymerase and has advanced into phase II trials. To clarify the drug resistance mechanisms of GS-9669 caused by M423T/I/V, L419M, R422K, and I482L mutations of NS5B polymerase (GT1b) and the receptor-ligand interactions during the binding process, a series of molecular simulation methods including molecular dynamics (MD) simulations and adaptive steered molecular dynamics (ASMD) simulations were performed for the wild-type (WT) and six mutant NS5B/GS-9669 complexes. The calculated results indicate that the binding free energies of the mutant systems are less negative than that of the WT system, indicating that these mutations will indeed cause NS5B to produce different degrees of resistance to GS-9669. The mutation-induced drug resistances are mainly caused by the loss of binding affinities of Leu419 and Trp528 with GS-9669 or the formation of multiple solvent bridges. Moreover, the ASMD calculations show that GS-9669 binds to the thumb II sites of the seven NS5B polymerases in distinct pathways without any obvious energy barriers. Although the recognition methods and binding pathways are distinct, the binding processes of GS-9669 with the WT and mutant NS5B polymerases are basically controlled thermodynamically. This study clearly reveals the resistance mechanisms of GS-9669 caused by M423T/I/V, L419M, R422K, and I482L mutations of HCV NS5B polymerase and provides some valuable clues for further optimization and design of novel NS5B inhibitors.

Evaluation of fiber-flaх varieties for resistance to lodging in the early stages of ontogenesis

The article analyzes the literature and presents the results of three-year studies of the problem of susceptibility of fiber - flax to their lodging, which is observed at different stages of ontogenesis. It is shown that the lodging of plants negatively affects the formation of morphological characteristics of flax, and unstable varieties have a lower content of lignin in the stem during intensive growth and budding, which leads to a significant reduction in seed productivity and sowing conditions. It is shown that increasing the resistance to lodging of flax stalks has an independent significance in breeding, but along with this there is an influence not only of soil and climatic conditions of cultivation, but also a contribution to the variability of genetic characteristics of the variety.In the analysis of correlations between economically valuable traits of flax, it was found that resistant to lodging forms with increased stem diameter are prone to late ripening, and in terms of increasing the fiber content for breeding more suitable thin-stemmed forms with reduced lodging resistance. High coefficients of positive correlation (r = 0.74‒0.91) between resistance to lodging and the number of leaves on the stem were determined. But these correlations are not general, and their level depends only on the characteristics of experimental samples. The patent search for methods for assessing resistance to lodging in the early stages of selection, which was conditionally divided into four groups, is analyzed. Weather conditions, materials and research methods are described. In the course of laboratory experiments the analysis of group of morphological signs of plants is carried out: the general height of a plant; length of the root system, the first internode and subcotyledonary knee; mass of the subcotyledonary knee and root system. Studies to determine the resistance to lodging of varieties of fiber-flax with different levels of manifestation of this feature of long flax were conducted on the 20-th day after full germination. Six varieties of long flax of different ecological and geographical origin and different groups of resistance to lodging were used.&#x0D; It was found that in flax varieties with different degrees of resistance to lodging in the early stages of ontogenesis changes the manifestation of morphological features in the direction of increasing the length of the first internode and subcotyledonary knee and decreases the overall plant height compared to unstable varieties as a result of response to change. There is no clear pattern between the degree of stability of varieties fiber – flax and the decrease in the mass of the subcotyledonary knee during shading. It is shown that shading of flax plants during research has a negative effect on the length of the root system in the early stages of ontogenesis.

Differential Regulation of Drought Responses in Two Phaseolus vulgaris Genotypes.

Drought is probably the most harmful stress affecting common bean crops. Domestication, worldwide spread and local farming practices has entailed the development of a wide variety of common bean genotypes with different degrees of resistance to water stress. In this work, physiological and molecular responses to water stress have been compared in two common bean accessions, PHA-0683 and PMB-0220, previously identified as highly and moderately resistant to water stress, respectively. Our hypothesis was that only quantitative differences in the expression patterns of key genes should be found if molecular mechanisms regulating drought resistance are similar in the two accessions. However, results presented here indicate that the resistance to drought in PMB-0220 and PHA-0683 common bean accessions is regulated by different molecular mechanisms. Differential regulation of ABA synthesis and ABA signaling related genes among the two genotypes, and the control of the drought-induced senescence have a relevant contribution to the higher resistance level of PHA-0683 accession. Our results also suggest that expression patterns of key senescence-related transcription factors could be considered in the screening for drought resistance in common bean germplasm collections.

Antifungal activity of essential oils from Cinnamomum cassia, Myristica fragrans and Syzygium aromaticum against Rhodotorula mucilaginosa

Rhodotorula genus comprises yeasts from Sporidiobolaceae family. Considered as non-pathogenic until the last two decades, different species of Rhodotorula are emerging as pathogens in humans, with R. mucilaginosa being the most commonly involved in infections, ranging from simpler clinical conditions such as skin manifestations to more severe cases such as meningitis and endocarditis. The major facilitating agents for the emergence of these infections are invasive procedures such as catheter implants. The primary drugs of choice used to treat these infections are amphotericin B and fluconazole. However, some strains of this yeast show different degrees of resistance to these substances, thus justifying the search for new therapeutic agents. Considering this, the present study aims the investigation of the antifungal activity of the essential oils of Cinnamomum cassia (cinnamon), Syzygium aromaticum (clove) and Myristica fragrans (nutmeg) against clinical isolates of R. mucilaginosa. The essential oils were obtained by hydrodistillation and characterized by GC-MS. The investigation of the antifungal action activity was performed by the agar disc-diffusion test followed by the Minimum Inhibitory Concentration (MIC) determination. All the essential oils were species present their oil characterized by the presence of phenylpropanoids, with eugenol (77.6 to 94.4%) as the main compound of clove and E-cinnamaldehyde (90.4 to 100%) of cinnamon. Nutmeg oil is characterized by the presence of showed as main compounds the myristicin (1.8 a 12.8%) and elemicin (4.3 a 11.1%) phenylpropanoids, besides sabinene (28.2 to 44.4%) and terpinen-4-ol (16.0 to 19.5%) monoterpenes. In the investigation of antifungal activity, all the oils showed potential action against clinical isolates of R. mucilaginosa, with MICs ranging from 8 to 500 µg/mL. The results demonstrate that these oils are promising candidates in the search for new anti-Rhodotorula agents, enabling the treatment of aforementioned infections.

Prevalence of Antibiotic Resistant Vibrio spp. in Finfish Sold in Tripoli Fish Markets, Libya

Background: The occurrence of Vibrio spp. in raw fish is common, especially from temperate climates regions, in both natural and farm environments, and in all kind of fish. Whereas, limited data have been reported on antibiotic resistance strains of Vibrio spp. Aim: The main objectives of this study were to determine the prevalence of Vibrio spp. including antibiotic resistance strains in fresh finfish samples as well as evaluation of their antibiogram. Material and methods: Samples of 122 fresh finfish were purchased from two main fish markets in Tripoli, Libya. Samples were examined for the presence of Vibrio spp. and its antibiogram. Results: A total of 68 Vibrio’s belonging to six different species were isolated, the most predominant species were V. fluvialis 45(66.2%), followed by V. alginolyticus 10(14.7%), V. cholera 9(13.2%), V. parahemolyticus 2(2.9%), V. vulnificus and V. hollisae 1(1.5%). All of the isolates showed different degree of resistance toward tested antibiotics. The isolates showed high resistance to cloxacillin, amoxicillin, vancomycin, amoxicillin/clavulanic acid, oxytetracylin, cephalothin, while for streptomycin the resistance rate was the lowest. Conclusion: The results demonstrated a high incidence of Vibrio spp. in raw finfish samples and this finding suggests that, fish sold in Tripoli fish markets could be a source of potential health hazard. This is because some of isolated strains were resistant to most popular antibiotics used in human and aquaculture treatments. Besides, study results indicated that, antibiotic resistance strains are common in raw finfish sold in both markets. Improvements in handling and processing are needed to minimize the prevalence of such pathogenic bacteria. ​Keywords: Vibrio spp., Finfish, Mullet, Sardine, Antibiotic Resistance.

Prévalence de Vibrio spp. dans le poisson à nageoire vendu aux marchés de poissons de Tripoli, Libye

Background: The occurrence of Vibrio spp. in raw fish is common, especially from temperate climates regions, in both natural and farm environments, and in all kinds of fish. Whereas, limited data have been reported on antibiotic resistance strains of Vibrio spp. Aim: The main objectives of this study were to determine the prevalence of Vibrio spp. including antibiotic resistance strains in fresh finfish samples as well as evaluation of their antibiogram. Material and methods: Samples of 122 fresh finfish were purchased from two main fish markets in Tripoli, Libya. Samples were examined for the presence of Vibrio spp. and its antibiogram. Results: A total of 68 Vibrios belonging to six different species were isolated, the most predominant species were V. fluvialis 45(66.2%), followed by V. alginolyticus 10(14.7%), V. cholera 9(13.2%), V. parahemolyticus 2(2.9%), V. vulnificus and V. hollisae 1(1.5%). All of the isolates showed different degrees of resistance toward tested antibiotics. The isolates showed high resistance to cloxacillin, amoxicillin, vancomycin, amoxicillin/clavulanic acid, oxytetracyline, cephalothin, while for streptomycin the resistance rate was the lowest. Conclusion: The results demonstrated a high incidence of Vibrio spp. in raw finfish samples and this finding suggests that, fish sold in Tripoli fish markets could be a source of potential health hazard. This is because some of the isolated strains were resistant to the most popular antibiotics used in human and aquaculture treatments. Besides, study results indicated that, antibiotic resistance strains are common in raw finfish sold in both markets. Improvements in handling and processing are needed to minimize the prevalence of such pathogenic bacteria. Keywords: Vibrio spp., Finfish, Mullet, Sardine, Antibiotic Resistance.

Adverse urbogeomorphological processes in the formation of harmful impurities in the air

The environmental problems of cities arose simultaneously with the cities themselves. Urban settlements in themselves (without special systems) do not correspond to the closed ecological type. The city is a large consumer of various resources, but it has virtually no conditions for waste disposal, recovery of resources. The negative side of urban life is the low quality of the natural environment and its main components - water, air, vegetation, etc .; saturation of its physical, chemical and biological contaminants. In general, the urban way of life generates abiological tendencies and "diseases of civilization". There is a direct relationship between the size of the city and the frequency of the disease. In large industrial cities, the incidence of allergic diseases is 10-20%, and in rural areas only 2-4%. The increase in allergic diseases among children is especially noticeable. The state of the urbanized natural-technogenic geomorphosystem can be assessed using a system of expert assessments, which ultimately allows to identify geomorphosystems with different degrees of resistance to man-made loads. In order to consistently study the state of the urban geomorphosystem and assess the stability of the terrain to man-made loads, it is proposed to carry out research at the following stages: Retrospective step-by-step analysis of the evolution of natural relief and historical-geomorphological territory based on the study of the history of settlement and development of geomorphological objects in the city. Assessment of the current state of the urbanized natural and man-made geomorphosystem. Zoning of the city territory according to the degree of potential geomorphological danger. Development of environmental recommendations and general forecasting of UPTG development taking into account geoecological risk. The retrospective step-by-step analysis of the evolution of natural relief includes two main stages: the study of the formation of the natural subsystem of UPTG in the future city and the stage of formation of natural-technogenic geomorphosystem in connection with urbanization. Based on historical and geomorphological analysis, a general picture of the use of geomorphological objects in the historical stage, three main stages of urbanization, which corresponded to a certain level of man-made loads on the terrain, namely: development without significant landforms (suburban); significant transformation of the relief without significant negative consequences (medieval and new); intensive urbanization with the emergence of zones of geoecological risk (modern). Estimation of the current state of the urbanized natural-technogenic geomorpho-system of logical conditions of the territory from the point of view of their resistance to man-caused influences and determination of the volumes of man-caused loads on the relief. To assess the man-made impact on the topography of the city, an inventory and classification of all sources of man-made impacts was conducted, the nature and intensity of this impact on the topography was studied. The structure of the modern city and the basis of functional zoning of the territory is subject to the same research. Assessment of the degree of man-made impact is carried out on a set of indicators that take into account the level of static and dynamic loads, the degree of relief, the presence and nature of man-made deposits. Static loads were determined by indicators of building density, density of water supply and sewerage mains, capacity of man-made sediments (alluvium, embankments, landfills). The intensity of static loads is estimated according to their types - engineering, construction, operation.