scholarly journals Environmental Concentrations of Sulfonamides Can Alter Bacterial Structure and Induce Diatom Deformities in Freshwater Biofilm Communities

2021 ◽  
Vol 12 ◽  
Author(s):  
Laura Kergoat ◽  
Pascale Besse-Hoggan ◽  
Martin Leremboure ◽  
Jérémie Beguet ◽  
Marion Devers ◽  
...  
Keyword(s):  
Surface Waters ◽  
Shannon Index ◽  
Cell Integrity ◽  
Diatom Community ◽  
Stream Mesocosms ◽  
Bacterial Structure ◽  
Ecological Realism ◽  
Community Exposure ◽  
Contamination Levels ◽  
Set Up

Since the early 1920s, the intensive use of antibiotics has led to the contamination of the aquatic environment through diffuse sources and wastewater effluents. The antibiotics commonly found in surface waters include sulfamethoxazole (SMX) and sulfamethazine (SMZ), which belong to the class of sulfonamides, the oldest antibiotic class still in use. These antibiotics have been detected in all European surface waters with median concentrations of around 50 ng L–1 and peak concentrations of up to 4–6 μg L–1. Sulfonamides are known to inhibit bacterial growth by altering microbial production of folic acid, but sub-lethal doses may trigger antimicrobial resistance, with unknown consequences for exposed microbial communities. We investigated the effects of two environmentally relevant concentrations (500 and 5,000 ng L–1) of SMZ and SMX on microbial activity and structure of periphytic biofilms in stream mesocosms for 28 days. Measurement of sulfonamides in the mesocosms revealed contamination levels of about half the nominal concentrations. Exposure to sulfonamides led to slight, transitory effects on heterotrophic functions, but persistent effects were observed on the bacterial structure. After 4 weeks of exposure, sulfonamides also altered the autotrophs in periphyton and particularly the diversity, viability and cell integrity of the diatom community. The higher concentration of SMX tested decreased both diversity (Shannon index) and evenness of the diatom community. Exposure to SMZ reduced diatom species richness and diversity. The mortality of diatoms in biofilms exposed to sulfonamides was twice that in non-exposed biofilms. SMZ also induced an increase in diatom teratologies from 1.1% in non-exposed biofilms up to 3% in biofilms exposed to SMZ. To our knowledge, this is the first report on the teratological effects of sulfonamides on diatoms within periphyton. The increase of both diatom growth rate and mortality suggests a high renewal of diatoms under sulfonamide exposure. In conclusion, our study shows that sulfonamides can alter microbial community structures and diversity at concentrations currently present in the environment, with unknown consequences for the ecosystem. The experimental set-up presented here emphasizes the interest of using natural communities to increase the ecological realism of ecotoxicological studies and to detect potential toxic effects on non-target species.

scholarly journals DYNAMICS OF FRUIT FLIES POPULATIONS IN TWO MANGO PRODUCTION ZONES (KORHOGO AND FERKÉ) IN NORTHERN CÔTE D’IVOIRE

2019 ◽  
Vol 7 (7) ◽  
pp. 256-264
Author(s):  
Minhibo Magloire Yves ◽  
Akpesse Akpa Alexandre Moïse ◽  
Coulibaly Tenon ◽  
Koua K Hervé ◽  
Coulibaly Adama
Keyword(s):  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Diversity Indices ◽  
Fruit Flies ◽  
Shannon Index ◽  
Bactrocera Dorsalis ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
Set Up ◽  
Study Sites

Fruit flies are a major constraint to the production and export of mangoes by causing the rot of mangoes. The objective of this work is to follow the fluctuation of population of flies in the northern part of Côte d'Ivoire between May 2015 and October 2016. A network of trapping flies using food baits (the Torula and Ceratrap) and sexual attractants (Methyl Eugenol and Trimedlure) were set up in Korhogo and Ferké mango orchards with the forest Diabaté Kamonon and the forest Petit Clerc as reference area. During trapping, 11 species of fruit flies were identified at all study sites. Among these species, Bactrocera dorsalis and Ceratitis cosyra, were the most abundant in the area. In general, diversity indices were low. The Ferké’s Forest has the highest Shannon index (H = 1.20). This index was higher than the index found in Ferke's orchards (0.9398). At Korhogo the Shannon index in orchards (H = 0.84) is higher than in the forest (H = 0.41). It has been observed that the genus Bactrocera swarmed on mango orchards when precipitation was plentiful. While the genus Cerartitis only appeared when precipitation was low. In addition, knowledge of the ecology and fluctuation of fruit flies, will allow to develop a site monitoring device through a trapping system with sexual and food attractants.

scholarly journals Early westward flow across the Tasman Gateway

2015 ◽  
Vol 11 (5) ◽  
pp. 5021-5048
Author(s):  
W. P. Sijp ◽  
A. S. von der Heydt ◽  
P. K. Bijl
Keyword(s):  
Southern Ocean ◽  
Ocean Circulation ◽  
Surface Waters ◽  
Middle Eocene ◽  
Drake Passage ◽  
Easterly Wind ◽  
Wind Pattern ◽  
Sw Pacific ◽  
Field Evidence ◽  
Set Up

Abstract. The timing and role in ocean circulation and climate of the opening of Southern Ocean gateways is as yet elusive. Recent micropaleontological studies suggest the onset of throughflow of surface waters from the SW Pacific into the Australo-Antarctic Gulf through a southern shallow opening of the Tasman Gateway from 49–50 Ma onwards. Here, we present the first model results specific to the early-to-middle Eocene where, in agreement with the field evidence, southerly shallow opening of the Tasman Gateway indeed causes a westward flow across the Tasman Gateway. As a result, modelled estimates of dinoflagellate biogeography are in agreement with the recent findings. Crucially, in this situation where Australia is still situated far south and almost attached to Antarctica, the Drake Passage must be sufficiently restricted to allow the prevailing easterly wind pattern to set up this southerly restricted westward flow. In contrast, an open Drake Passage, to 517 m depth, leads to an eastward flow, even when the Tasman Gateway and the Australo-Antarctic gulf are entirely contained within the latitudes of easterly wind.

scholarly journals Effects of artificial sweeteners on Lemna minor

2018 ◽  
Vol 36 (No. 5) ◽  
pp. 386-391 ◽  
Author(s):  
Klára Kobetičová ◽  
Klára Anna Mocová ◽  
Lucie Mrhálková ◽  
Šárka Petrová
Keyword(s):  
Chlorophyll Content ◽  
Surface Waters ◽  
Growth Parameters ◽  
Lemna Minor ◽  
Artificial Sweeteners ◽  
Negative Effects ◽  
Response Curves ◽  
Freshwater Plants ◽  
Set Up ◽  
The Impact

Artificial sweeteners are common micropollutants in the aquatic environment. They were detected both in surface waters and in groundwater. Human toxicity has also been studied quite intensively but their ecotoxicity has not been studied so far. To assess the impact of four artificial sweeteners (aspartame, sucralose, saccharine, and acesulfame K) and one natural sweetener (stevioside) on freshwater plants, a growth inhibition test was set up in the macrophyte duckweed (Lemna minor). Subsequently full dose-response curves were established by exposing L. minor plants to concentrations of each individual sweetener ranging from 6.25 mg/l up to 100 mg/l for 7 days. Three different endpoints were tested: frond number, frond area and total chlorophyll content. Tests were performed under sterile conditions. Sweeteners had various effects on Lemna plants. Saccharine, acesulfame K and stevioside did not cause any significant negative effects on any of the measured parameters. On the contrary, stevioside and saccharine caused slowly stimulative effects. Aspartame and sucralose inhibited growth parameters (frond number and frond area) but the chlorophyll content was not affected.

scholarly journals Microbial population dynamics during traditional production of Mabisi, a spontaneous fermented milk product from Zambia: a field trial

2020 ◽  
Vol 36 (12) ◽  
Author(s):  
Anneloes E. Groenenboom ◽  
John Shindano ◽  
Nachimuka Cheepa ◽  
Eddy J. Smid ◽  
Sijmen E. Schoustra
Keyword(s):  
Fermented Milk ◽  
Shannon Index ◽  
Lag Phase ◽  
Milk Product ◽  
Physico Chemical ◽  
Significant Difference ◽  
Set Up ◽  
Rural Zambia ◽  
Fermented Milk Product ◽  
Over Time

AbstractMabisi is a fermented milk product, traditionally produced in a calabash by uncontrolled fermentation. Due to high costs and a reduced availability of calabashes, nowadays plastic containers are also used for Mabisi production. However, the effect of this change in production practice on the properties of the product has not been documented. Therefore, we aimed at determining the effect of fermentation vessels and types of back-slopping on acidification and microbial communities during fermentation. A series of fifteen experiments using two types of fermentation vessels (plastic buckets and calabashes) in combination with different types of back-slopping (no back-slopping, passive back-slopping, and active back-slopping) were set up at a field site in rural Zambia. In each of the fifteen fermentations we analysed acidification rate of traditional Mabisi fermentation and bacterial diversity over time. No significant difference was found in terms of microbial diversity during and at the end of fermentation between fermentations performed in buckets or previously used calabashes. Bacterial communities in general decreased in diversity over time, where the drop in pH correlated with a decrease in Shannon Index. In case of active back-slopping, the pH drop started right after inoculation while in the no back-slopping and passive back-slopping fermentations, there was a clear lag phase before acidification started. All experimental series resulted in a microbial community dominated by Lactococcus lactis and a Shannon Index, as a measure for diversity, between 0.6 and 2.0. The use of plastic buckets for Mabisi fermentation can be a valuable alternative to the use of calabashes as this study showed no biological and physico-chemical differences between Mabisi resulting from both fermentation vessels, although the reason for perceived differences should be further investigated.

Determination of Hazardous Fractions in Tannery Landfill Leachate

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Andreja gajnar Gotvajn ◽  
Jana Zagorc-Koncan
Keyword(s):  
Surface Waters ◽  
Management Strategies ◽  
Treatment Method ◽  
Air Stripping ◽  
Adequate Treatment ◽  
Reduction Methods ◽  
Organic Fractions ◽  
Set Up ◽  
Land Filling

Land-filling is widely accepted and used in many waste management strategies, but it can constitute hazard for the environment. A study was conducted to evaluate the environmental hazard of a leachate flowing into surface waters without adequate treatment. The investigated leachate has been formed at an industrial landfill, where non-hazardous wastes from all phases of tanning processes including wastewater treatment were disposed. Collected leachate was characterised in terms of biodegradable (as reflected by its average BOD5 value 420-600 mg?L-1) and recalcitrant fractions (average COD was 1200-3400 mg?L-1). To set up a satisfactory treatment method for removal of pollutants from the leachate different toxicity reduction methods were employed to identify groups of substances most hazardous to the environment. We have used filtration, air stripping, adsorption on activated carbon, coagulation-flocculation processes and advanced oxidation with Fe2+/H2O2. It has been estimated that an effective treatment of the leachate could be achieved by the removal of persistent organic fractions and ammonium to avoid broad contamination of surface and groundwater; and this will minimise its serious risk to ecosystems and human health if the chemicals from the leachate migrate to drinking water catchments areas.

scholarly journals Effects of different hydrogen concentrations on rhizosphere bacteria of soybean (Glycine max L.)

2021 ◽  
pp. 775-780
Author(s):  
Lin Wang ◽  
Bei Liu ◽  
Haiyan Li ◽  
Xiaoping Liang ◽  
Lulu Li ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Shannon Index ◽  
Soil Samples ◽  
Series Data ◽  
Hydrogen Treatment ◽  
Sequencing Technology ◽  
Treated Sample ◽  
Bacterial Structure ◽  
Glycine Max L ◽  
And Cluster Analysis

Effects of hydrogen concentrations on the diversity and changes of bacterial community structure, soybean rhizosphere soil samples were investigated. The high-throughput sequencing technology of illumina was adopted to determine the bacterial 16S rRNA V3+V4 region series. Data processing such as splicing, filtering, removing chimeric sequences, and cluster analysis was then performed based on the raw data, and the tax was annotated with OTU. When the air-treated soil samples were compared with the ones treated with hydrogen at a concentration of 1100 ppm and 1300 ppm, the abundance of Proteobacteria increased and Actinobacteria decreased for the later. In addition the Simpson index decreased and the Shannon index increased significantly for both hydrogen-treated samples. However, for the soil sample treated with 1500 ppm of hydrogen, the above-mentioned two indexes didnot vary obviously compared with the air-treated sample. The results demonstrated that the rhizosphere bacterial structure diversity of soybean was significantly increased after hydrogen treatment at the concentration of 1100 and 1300 ppm. Bangladesh J. Bot. 50(3): 775-780, 2021 (September) Special

A genetic screen reveals a role for the late G1-specific transcription factor Swi4p in diverse cellular functions including cytokinesis

1997 ◽  
Vol 110 (14) ◽  
pp. 1647-1654 ◽  
Author(s):  
J.C. Igual ◽  
W.M. Toone ◽  
L.H. Johnston
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Ectopic Expression ◽  
Single Copy ◽  
Restrictive Temperature ◽  
Cell Integrity ◽  
Cellular Functions ◽  
Synthetic Lethal ◽  
Cellular Processes ◽  
Set Up

The transcription factor Swi4p plays a crucial role in the control of the initiation of the cell cycle in budding yeast. To further understand Swi4p function, we set up a synthetic lethal screen for genes interacting with SWI4. Fourteen conditional mutations which resulted in lethality only in the absence of SWI4 have been isolated. Only two of them were suppressed by ectopic expression of CLN2, indicating that Swi4p is involved in diverse cellular processes in addition to its requirement for CLN1,2 regulation. In most of the mutants a cell cycle phenotype was observed, including defects in G1 progression, budding, the G2/M transition and cytokinesis. In addition, four of the mutations resulted in massive cell lysis at the restrictive temperature, indicating that Swi4p is involved in the maintenance of cell integrity. One of the mutants, rsf1 swi4delta, was characterized in detail and it is defective in cytokinesis at the restrictive temperature. Staining with Calcofluor revealed that the rsf1 swi4delta mutant is impaired in chitin biosynthesis. rsf1 is allelic to the AGM1 gene, coding for N-acetylglucosamine-phosphate mutase, an enzyme involved in the biosynthesis of chitin. A single copy of SWI4 suppressed the cytokinesis defect. The above data suggest that Swi4p has a role in cytokinesis and becomes essential in this process when chitin biosynthesis is compromised. As overexpression or ectopic expression of CLN did not suppress the rsf1 swi4delta mutant phenotype, Swi4p must control some other gene(s) involved in cytokinesis.

Changing the layout of farmers markets can affect cross-contamination

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Karla M. Acosta ◽  
Zahra H. Mohammad ◽  
Heyao Yu ◽  
Kristen Kirkwood ◽  
Kristen Gibson ◽  
...  
Keyword(s):  
Social Cognitive ◽  
Farmers Markets ◽  
Contamination Level ◽  
Cross Contamination ◽  
Fluorescent Compound ◽  
Farmers Market ◽  
Content Type ◽  
Contamination Levels ◽  
Set Up ◽  
The Impact

PurposeThe purpose of this study was to investigate whether the layout has an effect on cross-contaminations levels at farmers markets.Design/methodology/approachWe used social cognitive theory's triadic reciprocity model to investigate how influencing the environment could change the behaviors of farmers’ market consumers and reduce the risk of microbial cross-contamination using a Fluorescent Compound (FC). For this purpose, a 3 × 2 experimental between-subject factorial design was utilized in this study: three farmers market layouts (i.e. U-shaped [U-S], L-shaped [L-S] and square-shaped [S–S]) and two different set-ups per market (i.e. produce and non-produce vendors completely separated, and alternating produce and non-produce vendors). FC was utilized to simulate microbial contamination on the participants (n = 54) hands. The participants were allowed to walk through the layout for 3 min and touch items after which a total of 475 swab samples were processed and recorded for absorbance levels.FindingsThe results indicated that the cross-contamination level of the U-S market was significantly lower (p < 0.001) than those of the L-S and S–S markets. The best market layout and set-up based on the average levels of simulated cross-contamination were the U-S market, particularly with the A set-up, where produce and non-produce booths were scattered.Originality/valueThis study is the first to use the quantification of FC to identify the impact of a farmers’ market layout/design on cross-contamination levels. These results can be used to provide guidance to market managers on layout and design from a safety standpoint to reduce the risk of cross-contamination.

scholarly journals Application of Stable Water Isotopes to Improve Conceptual Model of Alluvial Aquifer in the Varaždin Area

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 379 ◽  
Author(s):  
Tamara Marković ◽  
Igor Karlović ◽  
Melita Perčec Tadić ◽  
Ozren Larva
Keyword(s):  
Groundwater Flow ◽  
Conceptual Model ◽  
Surface Waters ◽  
Transport Model ◽  
Alluvial Aquifer ◽  
Stable Water Isotopes ◽  
Air Masses ◽  
Set Up ◽  
The Relationship ◽  
The Town

To understand groundwater flow and geochemical processes within an aquifer, it is necessary to set up a conceptual model of the aquifer. To accomplish this, different methods are used, and one of them is an isotopic technique. The study area is located in the Varaždin area (NW Croatia). The aquifer represents the main source of potable water for the town of Varaždin and the surrounding settlements. The conceptual model of the alluvial aquifer has to be set up prior to creating a groundwater flow and transport model. Measurements of ratios δ18Ο and δ2H in ground- and surface waters and precipitation samples were carried out. The relationship between ratios δ18Ο, δ2H, and d-excess for local precipitation in the study area showed that precipitation originates from the Atlantic air masses, although during the colder periods of the year, influence of the Mediterranean air masses was not negligible. The monitored period was warmer and wetter than average. Evaporation was observed at all monitored surface waters, but the largest rate was at the location of a gravel pit in Šijanec. The isotopic composition of the precipitation and groundwater showed a good correlation due to the isotopic homogenization of groundwater along the flow path.

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