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Abstract

Introduction

As therapy-refractory giardiasis is an emerging health issue, this review aimed at summarizing mechanisms of reduced antimicrobial susceptibility in Giardia duodenalis and strategies to overcome this problem.

Methods

A narrative review on antimicrobial resistance in G. duodenalis was based upon a selective literature research.

Results

Failed therapeutic success has been observed for all standard therapies of giardiasis comprising nitroimidazoles like metronidazole or tinidazole as first line substances but also benznidazoles like albendazole and mebendazole, the nitrofuran furazolidone, the thiazolide nitazoxanide, and the aminoglycoside paromomycin. Multicausality of the resistance phenotypes has been described, with differentiated gene expression due to epigenetic and post-translational modifications playing a considerable bigger role than mutational base exchanges in the parasite DNA. Standardized resistance testing algorithms are not available and clinical evidence for salvage therapies is scarce in spite of research efforts targeting new giardicidal drugs.

Conclusion

In case of therapeutic failure of first line nitroimidazoles, salvage strategies including various options for combination therapy exist in spite of limited evidence and lacking routine diagnostic-compatible assays for antimicrobial susceptibility testing in G. duodenalis. Sufficiently powered clinical and diagnostic studies are needed to overcome both the lacking evidence regarding salvage therapy and the diagnostic neglect of antimicrobial resistance.

Open access

Abstract

Interest in organic growing systems that means no harm to the environment, mankind, and the world’s natural ecosystem is increasing. This study evaluated the impact of organic versus conventional cultivation method on eggplants (Topan-374 and Pala-49), tomatoes (Rio Grande and Pink), and bell pepper (Kandil dolma) considering individual phenols, total phenol-flavonoid content, antioxidant capacity, and antibacterial potential. Peel and pulp of eggplants were evaluated separately. Organic cultivation enhanced trans-ferulic acid in the peels of both eggplant cultivars and the pulp of Pala-49. Organic Pala-49 had also higher amounts of cyanidin and caffeic acid in the peel, and only caffeic acid in the pulp. Chlorogenic acid was found in higher quantities in organic Rio Grande tomato and bell pepper. All organically grown vegetables in our study had significantly higher total phenol and flavonoid contents than conventional ones except Pink tomato. Organic farming significantly enhanced the antioxidant capacity of both eggplant cultivars. Only organic peel of Pala-49 eggplant cultivar had antibacterial activity against Staphylococcus epidermidis. Organic cultivation has an advantage in terms of antioxidant potential and phenolic constituents, and it enhanced the nutraceutical potential of both cultivars of eggplant, Rio Grande tomato, and bell pepper.

Open access

Abstract

The insecticidal efficacy of the experimental bioinoculants (Natur Nova, Natur Agro Hungary Ltd., Hungary) containing Beauveria bassiana (Bals.-Criv). Vuill. and Metarhizium anisopliae Metschnikoff against stored product pests modelled by granary weevil, Sitophilus granarius L. was evaluated on wheat in laboratory tests. In order to comparability, two applications were also set up: one purely ash-treated grain treatment against wireworms and a soil-injected one. Our results confirmed that some biopesticides can exert unexpected effect on non-target arthropods. However, the examined biopesticides were as empirically effected against the target arthropods regarding wireworms. Nevertheless, the application exempt from ash of the examined bioinoculants Natur Nova containing B. bassiana and M. anisopliae were not suitable for the elimination of the stored product pests modelled by S. granarius. In contrast, the putative plant protection effect of these biopesticides was observed in the course of applying the agents in the recommended environment and pest species as well as when applying them with ash carrier.

Open access

Néhány potenciálisan mérgező fém frakcióinak meghatározására alkalmazott analitikai módszer értékelése eltérő fizikai talajféleségű mintákon

Evaluation of analytical methods for the determination of different potentially toxic metal fractions in soils with different physical properties

Agrokémia és Talajtan
Authors: Kovács Katalin, Horváth Márk, Halász Gábor, Takács Anita, Heltai György, Boros Norbert, Sipos Péter, and Győri Zoltán

Munkánk során potenciálisan toxikus fémek frakcióinak meghatározására alkalmazott analitikai módszereket kívántunk értékelni, azok talajféleségtől való függése alapján.

A talajféleségtől való függés mértéke döntően megszabja a módszer használhatóságát. Jelen dolgozat célja, hogy a Cu, a Zn, a Fe és a Ni környezeti mobilitása szempontjából értékelje a vizsgálatba vont egy- és többlépéses kioldásos módszereket.

Vizsgálatainkhoz a TIM adatbázisból származó négy, eltérő fizikai talajféleségű mintát választottunk (homok-, homokos vályog-, vályog- és agyag-talaj sorrendjében növekvő agyag- és humusztartalommal és pH-val).

Öt különböző kivonószerrel végzett egylépéses extrakciót és kétféle szekvens, azaz 3+1 lépéses egymás utáni extrakciós vizsgálatot végeztünk (BCR és McGrath módszerekkel).

Elvégeztük a minták Magyar Szabvány (MSZ 21470-50) szerinti, mikrohullámú kezeléssel egybekötött, H2O2+HNO3 eleggyel való roncsolását is. Az így megállapított elemtartalom környezetvédelmi szempontból teljes („összes”) elemtartalomnak tekinthető.

A mérési eredmények alapján megkíséreltük kiválasztani a vizsgálatba vont módszerek közül azokat, amelyek a talajból már biztonsággal meghatározható mennyiségű elemet vonnak ki, de a kivont mennyiség még nem a teljes elemtartalommal arányos.

A mikrohullámú feltárással kapott Zn-, Cu-, Fe- és Ni-tartalmak, a homok-, homokos vályog-, vályog- és agyag-talaj sorrendben, vagyis az agyag- és humusztartalmukkal, valamint pH-jukkal párhuzamosan nő. Egy olyan összetett rendszerben, mint a talaj, az egyes talajtulajdonságok, így az agyag- és humusztartalom, valamint a pH hatása vizsgálataink alapján nem különíthető el, de mint várható volt, a nagyobb agyag- és humusztartalmú és magasabb pH-jú talajok ezekből az elemekből többet halmoztak fel.

Mivel a kelátképzőket tartalmazó kivonószerek az összes réztartalomnak mintegy harmadát kivonták, a kivont mennyiség a réztartalommal volt arányos, vagyis a réztartalom növekedésével párhuzamosan nőtt.

Ezek a kivonószerek tehát Cu esetében kevésbé alkalmasak az egyes talajféleségek toxicitása közti különbségek kimutatására.

A rézzel ellentétben, a másik három elemnél az egyes talajféleségeknél kivont kis elemmennyiségek esetenként nagyságrendileg is különböztek, így az elméleti meggondolásunknak megfelelően feltételezhető, hogy az egyes talajféleségek toxicitása közti különbséget mutatják.

A két szekvens módszernél a vasnál kapott mérési eredményeket azok szórása miatt nem lehetett értékelni.

Megállapítható, hogy a BCR agresszívebb kivonószereket használ, mint a McGrath módszer, ennek megfelelően a BCR módszerrel a talajok átlagában az elemek 36, a McGrath módszerrel pedig csak 9%-át vontuk ki.

A BCR módszernél nincs vízszerű gyenge kivonószer, amiből a különböző talajok összes elemtartalmából felszabaduló ionok mennyiségére lehetne következtetni. Az ecetsav, a leggyengébb kivonószer, de a kicserélhető elemtartalom mellett kivonja a karbonátokhoz kötött, vagyis biztosan nem szabad ionos elemtartalmat is.

Mivel a BCR módszer minden kivonószerével sok elemet vonunk ki, nincs érdemi különbség az elemek egyes talajoknál mért kivonási százaléka között, ami figyelembe véve, hogy a talajok elemtartalma a homoktól az agyagtalajig nő, azt jelenti, hogy a kivont mennyiség az összes elemtartalommal arányos.

Lényegében ugyanezt mondhatjuk a McGrath módszer két agresszívebb kivonószeréről is, annak ellenére, hogy lényegesen kevesebb elemet vonnak ki. Ezzel szemben a módszer leírása szerint, a 0,1 mólos kalcium-kloridos kivonatból a vízoldható és kicserélhető elemtartalomra lehet következtetni, így minden bizonnyal a talajok toxicitását mutatja.

In this study, we aimed to evaluate some analytical methods used to determine the fractions of potentially toxic metals, based on their dependence on soil type.

The degree of dependence on soil type determines the applicability of the method. The aim of the present paper is to evaluate the single- and multi-step extraction methods included in the study in terms of the environmental mobility of Cu, Zn, Fe and Ni.

For the studies, we selected four samples with different physical soil types from the Soil Information and Monitoring System database.

In order to establish trends, soil samples were selected so that their clay and humus content, i.e., their adsorption capacity as well as their pH increased in the order of sand, sandy loam, loam and clay soils.

One-step extractions with five different extractants and two sequential extraction analyses including 3+1 steps were performed (BCR and McGrath methods).

We also performed the digestion of the samples with H2O2 + HNO3 solvent combined with microwave treatment according to the Hungarian Standard (MSZ 21470-50). The element content determined in this way can be considered as the "total" element content from the environmental point of view.

Based on the results of the analyses, we tried to select from the methods included in the study those that already extract a safe amount of elements from the soil, but the extracted amount is not yet proportional to the total element content.

The Zn, Cu, Fe and Ni contents resulting from microwave digestion increased in the order of sand, sandy loam, loam and clay soils, i.e. in parallel with the clay and humus content and pH of the soils.

As the extractants containing chelating agents extracted about one-third of the total copper content, the amount extracted was proportional to the copper content, i.e. it increased in parallel with the increase in copper content. Thus, in the case of copper, these extractants are less suitable for detecting differences in the toxicity of different soil types.

In contrast to copper, in the case of the other three elements, the small amounts extracted from each soil type also differed in order of magnitude, so according to our theoretical consideration, it can be assumed that they show a difference between the toxicity of each soil type.

The results obtained with iron using the two sequential methods could not be evaluated due to their standard deviation.

It can be stated that BCR uses more aggressive extractants than the McGrath method, accordingly, the BCR method extracted 36%, whereas the McGrath method only 9% of the elements on average of the soils.

The BCR method does not have an aqueous weak extractant, which would indicate the amount of ions released from the total element content of the different soils. Acetic acid is the weakest extractant, but in addition to the exchangeable element content, it also extracts the ionic element content bound to carbonates, which is certainly not free.

Because a large amount of elements is extracted with each extractant in the BCR method, there is no significant difference in the percentage of elements extracted for each soil, which, given that soil element content increases from sand to clay soil, means that the extracted amount is proportional to total element content.

Basically, the same can be said for the two more aggressive extractants of the McGrath method, despite the fact that they extract significantly less amount of elements. In contrast, as described in the method, the water-soluble and exchangeable element content can be inferred from the 0.1 M calcium chloride extract, thus it certainly indicates soil toxicity.

Open access

Abstract

Metastatic human sarcomas temporarily respond to radio-chemotherapy relapse and remain highly resistant to further combination chemotherapy as to a curative effect, including checkpoint control.

Open access

Abstract

In this study, microbiological quality of 93 ready-to-eat food products was determined by enumeration of total aerobic bacteria and members of Enterobacteriaceae. Presence of Staphylococcus aureus and Listeria monocytogenes in the products were also investigated. Aerobic colony counts were between 1.9 × 102–3.4 × 108 CFU g−1 for 84.9% and Enterobacteriaceae counts were between 2 × 102 and 6.7 × 106 CFU g−1 for 43% of the samples. S. aureus was detected in 7.5% of the samples, but L. monocytogenes was not detected in any sample. 72.9% of the Enterobacteriaceae isolates showed resistance to at least one antibiotic tested, and 5 among the S. aureus isolates were found to be resistant to penicillin G and 2 against methicillin. Four S. aureus isolates produced only Staphylococcal enterotoxin A and 1 isolate produced both Staphylococcal enterotoxin A and B. Biofilm experiments revealed biofilm formation on polystyrene for 95.8%, 87.5%, and 91.6% of Enterobacteriaceae isolates at 4 °C, 22 °C, and 37 °C, respectively, whereas all S. aureus isolates formed biofilm at all temperatures.

Restricted access

Abstract

The objective of this research is to develop a dehusked coconut grading machine for coconut cultivators and entrepreneurs. The basis of design is characterized by a tapered belt conveyor and sizing board with openings of increasing aperture which run along the edge of the belt conveyor. Dehusked coconuts are fed onto the tapered belt conveyor where the gravitational force pushes the nut towards the edge until it comes in contact with sizing board. Due to the tangential force, the nut reels along the sizing board, where dehusked coconuts are graded and allowed to fall through aperture according to their sizes. Performance tests indicated that the inclination angle and velocity of the belt significantly affected contamination ratio, grading efficiency and capacity at 5% significance level. The most efficient configuration for fully husked coconut and semi husked was a belt speed of 1.3 m/s with the inclination angle of 15° and belt speed of 1.5 m/s with the inclination angle of 15° respectively. The machine is acceptable by coconut growers and entrepreneurs.

Restricted access