Inhibition Bioassay Research Articles

Emission Factors, Chemical Composition and Ecotoxicity of PM10 from Road Dust Resuspension in a Small Inland City

Road dust resuspension in urban environments can contribute to high human exposure to metal(loid)s, polycyclic aromatic hydrocarbons, and other potentially toxic organic compounds. However, for many regions, information on loadings, emission factors and chemical profiles is lacking to accurately apply emission inventories and source apportionment models. In the present study, PM10 samples were collected with an in situ road dust sampler from eleven representative streets of Bragança, an inland city of the Iberian Peninsula, and were analysed for organic and elemental carbon by a thermal-optical technique, elemental composition by ICP-MS and ICP-OES, and ecotoxicity by a luminescence inhibition bioassay with Allivibrio fischeri. A global emission factor of 5.36 ± 2.35 mg veh−1 km−1 was obtained but in suburban areas the values reached twice the average. Total carbon accounted for 14.9 ± 6.8% of the PM10 mass, while element oxides represented the largest share (28.6 ± 18.7%). Very high enrichments were found for typical traffic-related elements such as Cu, Zn, S, Pb and Ni. The geochemical index Igeo further confirmed that road dust of the study region is extremely contaminated by elements mainly originated from tyre and brake wear. Although the total non-carcinogenic and carcinogenic risks associated with metal exposure were found to be low for both children and adults, the bioluminescence inhibition assay showed (eco)toxic responses for all samples, indicating that road dust resuspension may pose a significant human health and ecological threat.

Winter indoor air quality in traditional Mongolian yurts, in a Ger district of Ulaanbaatar

In Ulaanbaatar roughly 60 % of the population live in traditional Mongolian yurts in the so-called Ger districts of the city. Winter indoor air quality is a serious concern in these districts as about 98 % of households consume solid fossil fuel (mainly coal). In our study, indoor air quality was assessed based on PAHs analysis and ecotoxicity testing of 24-hour samples collected in 4 yurts. Three of the selected yurts were equipped with conventional while the fourth one with improved stoves. Analysis of PAHs profiles showed the prevalence of higher molecular weight PAHs in all yurts. Concentrations of the 5-ring benzo(b)fluoranthene and 6-ring benzo(g.h.i)perylene were extremely high in one yurt using conventional stove, 8430 µg g−1 and 6320 µg g−1, respectively. Ecotoxicity of the samples was assessed using the kinetic version of the Vibrio fischeri bioluminescence inhibition bioassay. In concordance with PAHs concentrations, ecotoxicity was also the highest in that yurt.

Bioluminescence Inhibition Bioassay for Estimation of Snow Cover in Urbanised Areas within Boreal Forests of Krasnoyarsk City

It has been proposed that the level of air pollution in a city should be estimated based on the accumulation of pollutants in the snow cover of urban forests. This study presents a bioluminescence method for estimating the extent of snow cover pollution in the urbanised areas of boreal forests in Krasnoyarsk city. A bioluminescent assay involving NAD(P)H:FMN oxidoreductase (Red) and luciferase with luminous bacteria (BLuc) was employed to measure the concentrations of six heavy metals (As, Cd, Zn, Co, Hg, and Pb) in the snow cover. The tested snow samples demonstrated a correlation between the reduced activity of the enzyme system and variations in Cd concentration. Furthermore, the research indicated that the period of unfavourable meteorological conditions in Krasnoyarsk city resulted in a notable decline in the activity of the BLuc–Red enzyme system, which may be associated with elevated air pollution levels. This study underscores the potential of the bioluminescence method for monitoring environmental pollution in urban forested areas.

Synthesis and Antifungal Activity of Norbornene Carboxamide/sulfonamide Derivatives as Potential Fungicides Targeting Laccase.

To explore more potential fungicides with new scaffolds, thirty-seven norbornene carboxamide/sulfonamide derivatives were designed, synthesized, and assayed for inhibitory activity against six plant pathogenic fungi and oomycetes. The preliminary antifungal assay suggested that the title derivatives showed moderate to good antifungal activity against six plant pathogens. Especially, compound 6 e presented excellent in vitro antifungal activity against Sclerotinia sclerotiorum (EC50=0.71 mg/L), which was substantially stronger than pydiflumetofen. In vivo antifungal assay indicated 6 e displayed prominent protective and curative effects on rape leaves infected by S. sclerotiorum. The preliminary mechanism research displayed that 6 e could damage the surface morphology and inhibit the sclerotia formation of S. sclerotiorum. In addition, the in vitro enzyme inhibition bioassay indicated that 6 e displayed pronounced laccase inhibition activity (IC50=0.63 μM), much stronger than positive control cysteine. Molecular docking elucidated the binding modes between 6 e and laccase. The bioassay results and mechanism investigation demonstrated that this class of norbornene carboxamide/sulfonamide derivatives could be promising laccase inhibitors for novel fungicide development.

Nitrogen-reliant degradation behaviors of characteristic NHCs by UV-based advanced oxidation processes: Kinetics, pathways and toxicity assessment

In recent decades, nitrogen-containing heterocyclic compounds (NHCs) have been widely synthesized and applied due to their excellent coordination capability of heterocyclic N atoms. However, their high toxicity and poor biodegradability pose significant hazards to aquatic ecosystems. Three characteristic NHCs (cNHCs) with similar molecular structures but minor differences in the number and position of N atoms, namely benzotriazole (BTA), benzimidazole (BMZ), and indazole (IDZ), were selected to evaluate impacts of these differences on their degradation behaviors during UV/H2O2 treatments. It was found that the key mechanism for the removal of BTA, BMZ, and IDZ in the UV/H2O2 processes was the generation of ∙OH through UV-excited H2O2 decomposition. Density functional theory (DFT) calculations revealed that the variation in the number and position of heterocyclic ring N atoms significantly affected the electron cloud distribution of the cNHCs, thereby resulting in different reactivities. Mineralization results and N evolution experiments indicated that N elements were initially released in the form of ammonia nitrogen during UV/H2O2 treatments, which then underwent oxidation to form nitrite and nitrate. The two ortho-N atoms were most easily mineralized and release inorganic nitrogen, followed by the two meta-N atoms. However, the BTA compound containing three N atoms, exhibited inertness towards radicals after hydroxylation, thereby hindering mineralization. A dual-directional transformation products (TPs) identification protocol was employed to identify 30 TPs of the cNHCs and propose recommended degradation pathways. Furthermore, Vibrio fischeri bioluminescence inhibition bioassay and QSAR prediction models were used to preliminarily screen and identify 13 toxic TPs with potential ecological risks.

A yeast-based high-throughput screen identifies inhibitors of trypanosomatid HRG heme transporters with potent leishmanicidal and trypanocidal activity

ObjectivesNew drugs are required to treat neglected diseases caused by trypanosomatid parasites such as Leishmania, Trypanosoma brucei and Trypanosoma cruzi. An Achilles’ heel of these parasites is their heme auxotrophy; they have an absolute dependence on scavenging this molecule from the host, and trypanosomatid HRG heme transporters (TrypHRG) play an important role in this process. As these proteins are essential for the parasites and have low similarity with their human orthologue, they have been proposed as attractive therapeutic targets. Here, we have developed two yeast-based assays that allow an inexpensive high-throughput screening of TrypHRG inhibitors within a cellular context. MethodsWe first assessed that Leishmania major, Leishmania donovani and T. brucei HRG proteins were heterologously expressed in the digestive vacuole membrane of a mutant heme auxotrophic yeast strain. Here, TrypHRG imports hemoglobinderived heme into the cytosol, allowing mutant yeast to grow in the presence of low hemoglobin concentrations and promoting the activity of hemeproteins such as catalase, which was used as a reporter of cytosolic heme levels. ResultsIn the presence of a TrypHRG inhibitor, both catalase activity (test 1) and yeast growth (test 2) were diminished, being easily monitored. The assays were then tested on a pilot scale for HTS purposes using a collection of repurposing drugs and food antioxidants. Some of the TrypHRG inhibitors identified in yeast presented strong trypanocidal and leishmanicidal activity in the submicromolar range, proving the potential of this approach. ConclusionsCumulatively, it was shown that the inhibition bioassays developed were robust and applicable to large-scale HTS.

Synthesis of novel coumarin-based thiosemicarbazones and their implications in diabetic management via in-vitro and in-silico approaches

Diabetes mellitus has a high prevalence rate and it has been deemed a severe chronic metabolic disorder with long-term complications. This research aimed to identify compounds that could potentially inhibit the vital metabolic enzyme α-glucosidase and thereby exert an anti-hyperglycemic effect. The main goal was to establish an effective approach to control diabetes. To proceed with this study, a series of novel coumarin-derived thiosemicarbazones 3a–3m was synthesized and examined using a variety of spectroscopic methods. Moreover, all the compounds were subjected to α-glucosidase inhibition bioassay to evaluate their antidiabetic potential. Fortunately, all the compounds exhibited several folds potent α-glucosidase inhibitory activities with IC50 values ranging from 2.33 to 22.11 µM, in comparison to the standard drug acarbose (IC50 = 873.34 ± 1.67 µM). The kinetic studies of compound 3c displayed concentration-dependent inhibition. Furthermore, the binding modes of these molecules were elucidated through a molecular docking strategy which depicted that the thiosemicarbazide moiety of these molecules plays a significant role in the interaction with different residues of the α-glucosidase enzyme. However, their conformational difference is responsible for their varied inhibitory potential. The molecular dynamics simulations suggested that the top-ranked compounds (3c, 3g and 3i) have a substantial effect on the protein dynamics which alter the protein function and have stable attachment in the protein active pocket. The findings suggest that these molecules have the potential to be investigated further as novel antidiabetic medications.

Preliminary assessment of road dust from Portuguese motorways: chemical profile, health risks, and ecotoxicological screening

Among non-exhaust emissions, road dust resuspension represents a rather important contribution to particulate matter in urban areas. This study aimed to achieve a chemical characterisation of road dust particulate matter (PM10) on two motorway sections, one rural and one urban, and to explore the related health and ecotoxicological risks. Measured PM10 dust loadings reached very low levels (0.66–1.49 mg m-2) compared to equivalent studies in other road environments in Portugal and other countries. Emission factors ranged from 33 to 62 mg veh−1 km−1. The carbonaceous content represented 14% of the total PM10 mass, whereas the highest contribution to the mass was given by mineral matter. Elements such as Si, Al, Ca, Fe and K accounted for almost three quarters of the total element mass for all samples, whilst Cu and Zn, mostly associated with brake and tyre wear, were the most enriched elements in relation to the soil composition. Nonetheless, Ti and Zr presented the highest non-carcinogenic risks for human health. Despite the low amounts of particulate matter in the aqueous solution, the ecotoxicological screening with the Aliivibrio fisheri bioluminescence inhibition bioassay allowed to classify the samples as toxic.

Isolation of two triterpenoids from Phlomis purpurea, one of them with anti-oomycete activity against Phytophthora cinnamomi, and insights into its biosynthetic pathway.

Phytophthora cinnamomi is an important plant pathogen responsible for dieback diseases in plant genera including Quercus, Fagus, Castanea, Eucalyptus, and Pinus, among others, all over the world. P. cinnamomi infection exerts tremendous ecological and economic losses. Several strategies have been developed to combat this pathogenic oomycete, including the search for novel anti-oomycete compounds. In this work, a Mediterranean vascular plant, Phlomis purpurea, has been screened for secondary bioactivity against this pathogen. The genus Phlomis includes a group of herbaceous plants and shrubs described as producers of many different bioactive compounds, including several triterpenoids. Triterpenoids are well-known molecules synthesized by plants and microorganisms with potent antioxidant, antitumoral, and antimicrobial activities. We have isolated by HPLC-DAD and characterized by HPLC-MS and NMR two nortriterpenoid compounds (phlomispentaol A and phlomispurtetraolone) from the root extracts of P. purpurea. One of them (phlomispentaol A) is active against the plant pathogenic oomycete P. cinnamomi (based on in vitro inhibition bioassays). Based on their chemical structure and their relationship to other plant triterpenoids, oleanolic acid is proposed to be the common precursor for these molecules. The anti-oomycete activity shown by phlomispentaol A represents a promising alternative to counteract the worldwide-scale damage caused to forest ecosystems by this pathogen.

Road dust resuspension in a coastal Atlantic intermunicipal urban area with industrial facilities: Emission factors, chemical composition and ecotoxicity

Road dust resuspension in urban environments can be both a means of transport of pollutants across the various environmental compartments and a source of pollutants itself, becoming a potential threat to human health. With the aim of obtaining emission factors and achieving a detailed chemical characterisation of road dust (RD) in typical Portuguese cities, a sampling campaign was performed in the region of Aveiro. Locations were chosen for intercomparison in various urban environments with different land uses, from the busier city centre and university campus to residential neighbourhoods and harbour-commercial areas with industrial activities. PM10 samples were analysed for organic and elemental carbon (OC and EC) by a thermal-optical technique, elemental composition by PIXE, organic speciation by GC–MS, and ecotoxicology by a luminescence inhibition bioassay with Aliivibrio fischeri. A health risk assessment for elements and PAHs was carried out. Dust loadings of 1.9 ± 1.8 mg PM10 m−2 were registered overall, whereas in the most trafficked areas of city centre they reached more than three times the average. OC accounted for 6.5–15.5% of total PM10, but element oxides represented the largest mass fraction (61.4 ± 8.6%). A strong enrichment was detected mostly for typical traffic-related elements such as Cu, Zn, As, Br, Cr, Ni and Mo and interestingly, Rb and Se. The analysed organic compounds accounted for 3.66–11.0 mg g−1 PM10, including PAHs and aliphatics, with a clear dominance of plasticisers. Some other compounds attributed to non-vehicle sources, such as fatty acid alkyl esters, were also detected. As concerns the 16 priority PAHs, their total mass concentration ranged from 5.58 to 36.3 μg g−1 PM10, with clear variability between sampling spots. All samples caused an ecotoxicological reaction in the bioassay, but samples from harbour and commercial areas proved to be most toxic.

Invitro Anticoccidial Effect of Fractions of Chromolaena Odorata Extract on Sporulating Eimeria Tenalla Oocysts

Coccidiosis is an important cause of digestive system disorders in birds, especially the poultry. The aim of this study was to evaluate the in-vitro anticoccidial effects of the different fractions of Chromolaena odorata extracts on sporulated Eimeria tenella oocysts. Sporulation inhibition bioassay was used to evaluate the activity of crude methanol fraction of Chromolaena odorata extracts; n-hexane, ethyl acetate, and methanol fractions of Chromolaena odorata on sporulation of Eimeria tenella, which was used to cause coccidiosis. in the birds following oral inoculation of experimental broiler birds with oocysts. Post-mortem examination of dead birds showed lesions consistent with Eimeria tenella. The fractions of the Chromolaena odorata were examined for the oocysticidal activities. Amprolium an anticoccidial drug was used as control. The fractions were used in 4 doses: 0 mg/ml; 0.1 mg/ml; 0.2 mg/ml and 0.4 mg/ml. The control drug was used in corresponding doses. The highest oocysticidal activity of tested plant extracts and fractions was recorded. The n-hexane fraction of Chromolaena odorata gave the highest oocysticidal activity. This oocysticidal activity was noticed at lower concentrations but activity was found to be dose-dependent. The highest oocysticidal activity for the n-hexane fraction of Chromolaena odorata was at 65.67±2.08%. Amprolium showed no oocysticidal activity at all concentrations. However, other fractions of the Chromolaena odorata showed different levels of oocysticidal activities. The methanol fractions were secondary to the n-hexane while the ethyl acetate was the least. In conclusion, this study provides the basis for using Chromolaena odorata, especially the n-hexane fraction as preventive agents against coccidiosis and suggests their use as a feed additive in the control of coccidiosis.

Discovery of a Subnanomolar Inhibitor of Protoporphyrinogen IX Oxidase via Fragment-Based Virtual Screening.

Protoporphyrinogen IX oxidase (PPO, E.C. 1.3.3.4), a key functional enzyme existing in various organisms, is acknowledged to be one of the most important action targets in the development of herbicides due to its pivotal roles in chlorophyll and heme biosynthesis pathways. As our persistent research work on the discovery of novel PPO-inhibiting herbicides, a new compound methyl 2-((5-(3-chloro-4,5,6,7-tetrahydro-2H-indazol-2-yl)-6-fluorobenzo[d]thiazol-2-yl)thio)acetate (8aj, Ki = 16 nM) was screened out as a hit compound via a fragment-based virtual screening method performed in the Auto Core Fragment in silico Screening web server. Subsequently, through a fused process of "hit-to-lead" optimization guided by molecular simulation, a total of 30 3-chloro-4,5,6,7-tetrahydro-2H-indazol-benzo[d]thiazole derivatives were synthesized and characterized. The results of the enzymatic inhibition bioassay showed that more than half of the newly synthesized compounds displayed higher activity against Nicotiana tabacum PPO (NtPPO) than oxadiazon, a commercial PPO-inhibiting herbicide. In particular, compound 8ab, a subnanomolar inhibitor with a Ki value of 380 pM against NtPPO, was discovered, which showed to be 71-fold more active than the commercial control oxadiazon (Ki = 27 nM), and was proven to be the most potent PPO inhibitor so far. Furthermore, the greenhouse assay demonstrated that most of the synthetic compounds showed good herbicidal activity toward the tested weeds. Especially, compound 8ad (Ki = 670 pM) showed the most promising post-emergence herbicidal activity with a broad spectrum of weed control even at a concentration as low as 37.5 g a.i./ha and relatively safe to rice at a dosage of 150 g a.i./ha, indicating that 8ad has the greatest potential to be developed as a new herbicide for weed control in paddy fields. This work provides a paradigm for the rational design and discovery of a novel PPO-inhibiting herbicide guided by the fragment-based drug design.

Further undescribed cembranoids from South China Sea soft coral Sarcophyton ehrenbergi: Structural elucidation and biological evaluation

A detailed chemical investigation of the South China Sea soft coral Sarcophyton ehrenbergi has yield seven undescribed cembranoids, namely isoehrenbergol D and sarcoehrenolides F–K embodying a rare α,β-unsaturated-lactone moiety at C-6 to C-19, along with two known related compounds, ehrenbergol D and sarcoehrenolide A. Their structures and absolute configurations were unambiguously established in the light of extensive spectroscopic data analysis, modified Mosher's method, X-ray diffraction analysis, and quantum chemical computation method. In a bioassay for α-glucosidase inhibition, ehrenbergol D was evaluated as α-glucosidase inhibitor with an IC50 value of 13.57 μM.

ASSESSMENT OF QUORUM QUENCHING ACTIVITY OF SERRATIA SPP. ISOLATED FROM PLANT RHIZOSPHERE AGAINST QUORUM SENSING CONTROLLED BIOFILM-FORMING PATHOGENS

Quorum quenching is the process of blocking quorum sensing activity that can be used as an effective way to control quorum sensing dependent virulence in pathogens. Quorum quenching mechanisms prevent the development of antibiotic resistance in biofilm-forming microorganisms. Rhizospheric bacteria shows great diversity along with complex intra species interactions. Within this diversified environment many bacterial species with quorum sensing and quorum quenching ability are found in close vicinity. In this study rhizospheric soil of different plants was used to screen potential quorum quenchers. The rhizospheric bacterial isolates were tested for their ability to degrade/inactivate N-hexanoyl-l-homoserine lactone (C6HSL) molecules. Pigment inhibition bioassays were performed using Chromobacterium violaceum CV026 and C. violaceum 2656 to screen bacterial isolates possessing quorum quenching activity. The biofilm formation inhibition by six screened isolates was studied against different human pathogens such as Vibrio parahaemolyticus MTCC451, V. cholerae MTCC3906 and Pseudomonas aeruginosa PA01. Results revealed that biofilms were efficiently inhibited. Significant biofilm inhibition was revealed by two isolates and identified as S. marcescens subsp. sakuensis KRED, and S. nematodiphila using 16S rRNA gene sequencing technique. The partial purification of C6HSL inactivating quorum quenching molecule resulted in maximum pigment inhibition of C. violaceum 2656 at 80% saturation of ammonium sulphate. These findings revealed that S. marcescens subsp. sakuensis KRED and S. nematodiphila are found to be potential candidates to control biofilms in bacterial human pathogens.

In vitro anticoccidial activity of ethanolic leaf extract of Citrus aurantium L. against Eimeria tenella oocysts

This study was carried out to examine the anticoccidial effect of Citrus aurantium L ethanol leaf extract against the oocysts of Eimeria tenella isolated from broiler chickens. The fresh leaves of C. aurantium were collected from Emirate Garden, Katsina, authenticated, air-dried at room temperature, pulverised by milling and subjected to extraction. Sporulation inhibition bioassay was employed to examine the activity of C. aurantium ethanol extract on the sporulation of E. tenella oocysts. In this assay, deep well petri dishes containing 100 unsporulated oocysts were subjected to 2 ml of five different concentrations of the extract (2.5, 5, 10, 20 and 30 mg/ml) in triplicates while oocysts sporulated in 2.5% potassium dichromate solution (K2Cr2O7) and phenol served as control groups. The content of the Petri dishes was stirred to ensure adequate oxygenation. The experimental set-up was incubated at room temperature and examined after 24 and 48 hours for sporulation inhibition. The sporulated and unsporulated oocysts were determined by counting using the Mcmaster apparatus. Phytochemical screening of C. aurantium revealed the presence of alkaloids, saponins, carbohydrates, steroids and tannins. The result showed that ethanolic leaf extract of C. aurantium to possess anticoccidial activity against unsporulated oocysts of E. tenella in a concentration-dependent manner. There was significant difference (p < 0.05) in the sporulation inhibition activity, with the highest (97 ± 0.8%) at 30 mg/ml and the lowest activity (8 ± 1.0%) at 2.5 mg/ml concentration of the extract after 48 hours of incubation. There was a general trend of sporulation inhibition with an increase in the concentration of the plant extract. The findings from this study showed ethanol leaf extract of C. aurantium possesses a remarkable In vitro anticoccidial effect that may be further scientifically explicated.

Outdoor charcoal grilling: Particulate and gas-phase emissions, organic speciation and ecotoxicological assessment

Charbroiling is a major source of air pollution worldwide. In this study, the particulate and gas-phase emissions from the charcoal lighting phase and during the grilling of meat (pork and rump cap) and fish (sardine and salmon) on an outdoor barbecue grill were characterized. Some gaseous compounds (ethane, hexane, NO2, N2O, SO2, NH3, HCl) did not display significant variations between samples and the background level, indicating that they are not emitted during barbecuing. During the charcoal heating phase, levels of total volatile organic compounds (TVOCs) increased 6 times above the background value. Four-to 5-fold increases in TVOC concentrations were observed when grilling sardines and salmon, while rises of 1.3–1.5 were recorded for meat. Emission factors of 32.4 g PM10 kg−1 and 22.7 g TVOCs kg−1 were obtained for the biofuel ignition phase. PM10 emission rates of 472, 531, 1104 and 918 mg kg−1 were estimated for pork, rump cap, sardine and salmon charbroiling, respectively. TVOC emissions ranged from 23.9 mg kg−1 (pork) to 82.6 mg kg−1 (salmon). Organic carbon accounted for 35.0% of the PM10 emitted during the ignition and flaming phases of the biofuel but represented mass fractions of 56–64% of the particulate emissions during food charbroiling. About 235 organic compounds were quantified in the PM10 samples. The ecotoxicity was assessed using the kinetic version of the Vibrio fischeri bioluminescence inhibition bioassay. All samples were classified as very toxic or toxic. Ecotoxicity was statistically correlated with several n-alkanes, PAHs and alkyl-PAHs, anhydrosugars, acids, and phenolic compounds.

Exploring Bacillus thuringiensis as a model for endospore adhesion and its potential to investigate adhesins in Pasteuria penetrans.

AimsPhytonematodes are a constraint on crop production and have been controlled using nematicides; these are highly toxic and legislation in Europe and elsewhere is prohibiting their use and alternatives are being sought. Pasteuria penetrans is a hyperparasitic bacterium that form endospores and have potential to control root‐knot nematodes (Meloidogyne spp.), but their attachment to the nematode cuticle is host‐specific. Understanding host specificity has relied upon endospore inhibition bioassays using immunological and biochemical approaches. Phylogenetic analysis of survey sequences has shown P. penetrans to be closely related to Bacillus and to have a diverse range of collagen‐like fibres which we hypothesise to be involved in the endospore adhesion. However, due to the obligately hyperparasitic nature of Pasteuria species, identifying and characterizing these collagenous‐like proteins through gain of function has proved difficult and new approaches are required.Methods and ResultsUsing antibodies raised to synthetic peptides based on Pasteuria collagen‐like genes we show similarities between P. penetrans and the more easily cultured bacterium Bacillus thuringiensis and suggest it be used as a gain of function platform/model. Using immunological approaches similar proteins between P. penetrans and B. thuringiensis are identified and characterized, one >250 kDa and another ~72 kDa are glycosylated with N‐acetylglucosamine and both of which are digested if treated with collagenase. These treatments also affected endospore attachment and suggest these proteins are involved in adhesion of endospores to nematode cuticle.ConclusionThere are conserved similarities in the collagen‐like proteins present on the surface of endospores of both P. penetrans and B. thuringiensis.Significance and Impact of StudyAs B. thuringiensis is relatively easy to culture and can be transformed, it could be developed as a platform for studying the role of the collagen‐like adhesins from Pasteuria in endospore adhesion.

Specialized Metabolites from the Allelopathic Plant Retama raetam as Potential Biopesticides.

To cope with the rising food demand, modern agriculture practices are based on the indiscriminate use of agrochemicals. Although this strategy leads to a temporary solution, it also severely damages the environment, representing a risk to human health. A sustainable alternative to agrochemicals is the use of plant metabolites and plant-based pesticides, known to have minimal environmental impact compared to synthetic pesticides. Retama raetam is a shrub growing in Algeria’s desert areas, where it is commonly used in traditional medicine because of its antiseptic and antipyretic properties. Furthermore, its allelopathic features can be exploited to effectively control phytopathogens in the agricultural field. In this study, six compounds belonging to isoflavones and flavones subgroups have been isolated from the R. raetam dichloromethane extract and identified using spectroscopic and optical methods as alpinumisoflavone, hydroxyalpinumisoflavone, laburnetin, licoflavone C, retamasin B, and ephedroidin. Their antifungal activity was evaluated against the fungal phytopathogen Stemphylium vesicarium using a growth inhibition bioassay on PDA plates. Interestingly, the flavonoid laburnetin, the most active metabolite, displayed an inhibitory activity comparable to that exerted by the synthetic fungicide pentachloronitrobenzene, in a ten-fold lower concentration. The allelopathic activity of R. raetam metabolites against parasitic weeds was also investigated using two independent parasitic weed bioassays to discover potential activities on either suicidal stimulation or radicle growth inhibition of broomrapes. In this latter bioassay, ephedroidin strongly inhibited the growth of Orobanche cumana radicles and, therefore, can be proposed as a natural herbicide.

Chemical compounds, anti-aging and antibacterial properties of Rosa rugosa Purple branch

Rosa rugosa Purple branch is a rare continuously flowering variety of R. rugosa and also is one of main cultivar varieties of R. rugosa in China. Although R. rugosa has been successfully used in the field of cosmetics, there are also many reports on its chemical components. The chemical composition and application value in cosmetics of R. rugosa Purple branch are still limited. The purpose of this study was to investigate the chemical components in the petals of R. rugosa Purple branch as well as evaluate their skincare and antibacterial potentials through DPPH radical scavenging, tyrosinase inhibition, elastase inhibition and antibacterial bioassays. Two new compounds, isorhamnetin-3-O-(2"-O-galloyl)-β-D-glucopyranoside (1), kaempferol-3-O-β-D-glucopyranosyl-(1→2)-(6''-O-trans-p-coumaroyl)-β-D-glucopyranoside (2) and thirteen known compounds (3-15) were isolated and identified from the petals by bioassay-guided fractionation. All the compounds were isolated and reported from R. rugosa Purple branch for the first time, in which twelve of them are discovered from R. rugosa for the first time. The tyrosinase inhibitory activities of 1, 2, rosarugoside B (3), kaempfero-3-O-β-D-glucopyranosyl(1→2)-β-D-glucopyranoside (4), astragalin-2'',6''-di-O-gallate (8), quercetin-3-O-β-D-glucopyranosyl(1→2)-β-D-glucopyranoside (10), 2-phenylethyl-β-D-glucopyranoside (13), 2-phenylethyl-6-O-α-L-arabinofuranosyl-β-D-glucopyranoside (14), and 2-phenylethyl-D-rutinoside (15) were firstly reported here, in which 8 showed strong tyrosinase inhibitory activity with IC50 of 187.32 ± 0.18 μg/mL. There were eight compounds (1, 6-12) showed strong antioxidant activity, with the scavenging rates of DPPH radical ranging from 88.59% to 94.30% and the IC50 ranging from 4.22 to 13.85 μg/mL, among them, 1 and quercetin-3-O-(6''-O-Z-p-coumaroyl)-β-D-glucopyranoside (11) exhibited antioxidant activity for the first time. 3 exhibited moderate elastase inhibitory activity with IC50 of 148.67 ± 0.11 μg/mL. In addition, seven compounds (2, 5-8, 10-11) showed varying degrees of antibacterial activity. These results indicated that R. rugosa Purple branch had anti-aging, whitening and antibacterial activities, which can be further applied to the development of functional cosmetics.

Lovastatin production by an oleaginous fungus, Aspergillus terreus KPR12 using sago processing wastewater (SWW)

BackgroundLovastatin is one of the first statins to be extensively used for its cholesterol-lowering ability. It is commercially produced by fermentation. Species belonging to the genus Aspergillus are well-studied fungi that have been widely used for lovastatin production. In the present study, we produced lovastatin from sago processing wastewater (SWW) under submerged fermentation using oleaginous fungal strains, A. terreus KPR12 and A. caespitosus ASEF14.ResultsThe intra- and extracellular concentrations of lovastatin produced by A. terreus KPR12 and A. caespitosus ASEF14 were lactonized. Because A. caespitosus ASEF14 produced a negligible amount of lovastatin, further kinetics of lovastatin production in SWW was studied using the KPR12 strain for 9 days. Lovastatin concentrations in the intra- and extracellular fractions of the A. terreus KPR12 cultured in a synthetic medium (SM) were 117.93 and 883.28 mg L–1, respectively. However, these concentrations in SWW were 142.23 and 429.98 mg L–1, respectively. The yeast growth inhibition bioassay confirmed the antifungal property of fungal extracts. A. terreus KPR12 showed a higher inhibition zone of 14 mm than the ASEF14 strain. The two-way analysis of variance (ANOVA; p < 0.01) showed significant differences in the localization pattern, fungal strains, growth medium, and their respective interactions. The lovastatin yield coefficient values were 0.153 g g–1 on biomass (YLOV/X) and 0.043 g g–1 on the substrate, starch (YLOV/S). The pollutant level of treated SWW exhibited a reduction in total solids (TS, 59%), total dissolved solids (TDS, 68%), biological oxygen demand (BOD, 79.5%), chemical oxygen demand (COD, 57.1%), phosphate (88%), cyanide (65.4%), and void of nutrients such as nitrate (100%), and ammonia (100%).ConclusionThe starch-rich wastewater serves as a suitable medium for A. terreus KPR12 for the production of lovastatin. It simultaneously decontaminates the sago processing wastewater, enabling its reuse for irrigation/recreation.Graphical