Examining Waterways Near UF Campus for Antimicrobial Resistance

The use of clinical antibiotics has greatly increased the scope and severity of naturally occurring antimicrobial resistance (AMR) patterns. Processing of wastewater by wastewater treatment plants (WWTPs) reduces but does not eliminate the concentration of clinical antibiotics present. Bacterial communities residing in aquatic biofilms are more easily able to exchange genes than their planktonic counterparts and thus display a higher rate of AMR. Previous work has indicated the presence of clinical antibiotics and AMR genes in several aquatic systems worldwide. Gainesville, FL has a significant population density and is home to the state’s third-largest hospital as well as a major university; thus, environmental monitoring for AMR genes is a pertinent undertaking. Biofilms were sampled from sites along the Sweetwater Branch Creek upstream and downstream of the GRU Main Street Water Reclamation Facility (WWTP). Colonies were screened for resistance on R2A plates containing ampicillin, methicillin, or vancomycin. After four days, colonies were randomly selected for genetic analysis via polymerase chain reaction (PCR) and gel electrophoresis to detect corresponding antimicrobial resistance genes. Only two colonies of thirty-five were positive for AMR genes: one colony from the downstream site which displayed the ampC gene for ampicillin resistance and one upstream isolate which displayed the vanA gene for vancomycin resistance. The preliminary results of this sampling project indicate only a small amount of resistance present along the Sweetwater Branch Creek, though AMR dynamics may be better illuminated by further analysis.

Dynamics in brain activation and behaviour in acute and repeated social defensive motivated behaviour

In nature, confrontations between conspecifics are recurrent and related, in general, to the lack of resources such as food and territory. In this sense, adequate defence against a conspecific aggressor is essential for the individual’s survival and the group integrity. However, repeated social defeat is a significant stressor, promoting several behavioural changes, including on social defence per se. But what would be the neural basis of these behavioural changes? To explore some hypotheses about this, we investigated the effects of repeated social stress on neural circuits underlying the motivated behaviour social defence in male mice. The hypothalamus is an essential centre of these circuits. Different hypothalamic structures receive information about the conspecific from the medial amygdala and the bed nucleus of the terminal stria. Furthermore, the hypothalamus can receive environmental information via the septo-hippocampal-hypothalamic circuit. Both information is processed by the dorsal premammillary nucleus (PMD) and the ventrolateral portion of the ventromedial nucleus of the hypothalamus, which communicate with the periaqueductal grey, an important downstream site for behavioural emission. During our analysis, we observed that animals re-exposed three times to the aggressor spent more time in passive defence during their last exposure than in their first one. These animals also present a smaller mobilization of areas related to the processing of conspecific cues. In contrast, we did not observe changes in the PMD mobilization. Therefore, our data indicate that the balance between the activity of circuits related to conspecific processing and the PMD determines the pattern of social defence behaviour. Changes in this balance may be the basis of the adaptations in social defence after repeated social defeat.

Comparison of Antibiotic Resistance Profile of Escherichia coli between Pristine and Human-Impacted Sites in a River

Information on the actual existence of antibiotic-resistant bacteria in rivers where sewage, urban wastewater, and livestock wastewater do not load is essential to prevent the spread of antibiotic-resistant bacteria in water environments. This study compared the antibiotic resistance profile of Escherichia coli upstream and downstream of human habitation. The survey was conducted in the summer, winter, and spring seasons. Resistance to one or more antibiotics at upstream and downstream sites was on average 18% and 20%, respectively, and no significant difference was observed between the survey sites. The resistance rates at the upstream site (total of 98 isolated strains) to each antibiotic were cefazolin 17%, tetracycline 12%, and ampicillin 8%, in descending order. Conversely, for the downstream site (total of 89 isolated strains), the rates were ampicillin 16%, cefazolin 16%, and tetracycline 1% in descending order. The resistance rate of tetracycline in the downstream site was significantly lower than that of the upstream site. Furthermore, phylogenetic analysis revealed that many strains showed different resistance profiles even in the same cluster of the Pulsed-Field Gel Electrophoresis (PFGE) pattern. Moreover, the resistance profiles differed in the same cluster of the upstream and the downstream sites. In flowing from the upstream to the downstream site, it is plausible that E. coli transmitted or lacked the antibiotic resistance gene.

Niche Differentiation of Active Methane-Oxidizing Bacteria in Estuarine Mangrove Forest Soils in Taiwan

Mangrove forests are one of the important ecosystems in tropical coasts because of their high primary production, which they sustain by sequestering a substantial amount of CO2 into plant biomass. These forests often experience various levels of inundation and play an important role in CH4 emissions, but the taxonomy of methanotrophs in these systems remains poorly understood. In this study, DNA-based stable isotope probing showed significant niche differentiation in active aerobic methanotrophs in response to niche differentiation in upstream and downstream mangrove soils of the Tamsui estuary in northwestern Taiwan, in which salinity levels differ between winter and summer. Methylobacter and Methylomicrobium-like Type I methanotrophs dominated methane-oxidizing communities in the field conditions and were significantly 13C-labeled in both upstream and downstream sites, while Methylobacter were well adapted to high salinity and low temperature. The Type II methanotroph Methylocystis comprised only 10–15% of all the methane oxidizers in the upstream site but less than 5% at the downstream site under field conditions. 13C-DNA levels in Methylocystis were significantly lower than those in Type I methanotrophs, while phylogenetic analysis further revealed the presence of novel methane oxidizers that are phylogenetically distantly related to Type Ia in fresh and incubated soils at a downstream site. These results suggest that Type I methanotrophs display niche differentiation associated with environmental differences between upstream and downstream mangrove soils.

Preliminary Water and Sediment Quality Assessment of the Meycauayan River Segment of the Marilao-Meycauayan-Obando River System in Bulacan, the Philippines

Background. The Meycauayan River is considered one of the most severely polluted rivers in the Philippines due to heavy metal and organic pollution that has caused environmental degradation. Objectives. The aim of the present study was to provide insight on the current status of the Meycauayan River and outline an appropriate strategy to solve problems of organic and heavy metal contamination. Methods. The physical, chemical and biological characteristics of the water and sediments were analyzed and evaluated based on available local and international standards. Three sites (upstream, midstream and downstream) of the river were considered for the evaluation of water and sediment quality. Results. Dissolved oxygen, measured in the morning, was very low at the upstream sampling station (1.87 ppm) and even lower at the downstream site (0.49 ppm). The temperature for the three sites ranged from 28.03°C (upstream) to 30.75°C (downstream). Visual inspection indicated that the color of the water was gray upstream and midstream, and black at the downstream station. Biochemical oxygen demand exceeded the recommended limits of the Department of Environment and Natural Resources (DENR) of 7.0 ppm with values of 13.22 ppm (upstream) and 12.02 ppm (downstream). Chemical oxygen demand exceeded the limit of 20 ppm at the downstream site at 84 ppm. Dissolved oxygen did not reach the recommended limit of 5.0 ppm of the DENR. There was a high coliform count at both the upstream (3.5 × 104 colony-forming unit (cfu)/ml) and downstream (2.5 × 104) sites, which exceeded the limit of the United States Environmental Protection Agency (USEPA) of 126 cfu/100 ml. Heavy metals such lead (Pb), zinc (Zn), copper (Cu), manganese (Mn) and chromium (Cr) exceeded the severe effect level of the National Oceanic and Atmospheric Administration (NOAA), which could be detrimental to humans and aquatic life. The results of one-way analysis of variance showed significant differences (p <0.001) in pH, temperature, dissolved oxygen, conductivity, total dissolved solids, chemical oxygen demand, nitrates and phosphates for water quality and Pb, Zn, Cu, Mn and Cr for sediment quality across the study sites. Conclusions. The results of the present study indicate that the downstream site was more polluted, possibly due to the accumulation of pollutants coming from the upstream site. The deterioration of the Meycauayan River is a result of rapid industrialization, urbanization and population growth. Examination of the water quality of the Meycauayan River indicates that it is very polluted and requires an immediate solution. The results of the present study should be used as a basis for crafting strategies to rehabilitate the Meycauayan River. Competing Interests. The authors declare no competing financial interests. This study was funded by Pure Earth.

Water Quality Mixing Model (WQMM) for Environmental Flow Release Monitoring

&lt;p&gt;Environmental Flow Release monitoring can be an expensive undertaking in active watercourses normally suitable for run-of-river hydropower projects.&amp;#160; In order to attain acceptable (&lt;10%) uncertainty in the derived flow series, it is necessary for a Qualified Professional (QP) to make several site visits to measure a range of flows in order to calibrate a stage-discharge (rating) curve.&amp;#160; With climate change, the need to measure drought conditions and respond appropriately is crucial for habitat health and to prevent fish stranding.&amp;#160; The current study employs a Water Quality Mixing Model (WQMM) to estimate flows at a downstream site from an existing hydropower plant using a modified constant rate mixing model.&amp;#160; This is an independent estimate of flow entirely distinct from the stage-discharge curve.&amp;#160; The method can be employed anywhere there is a sufficient mixing length and sufficiently distinct WQ traits.&amp;#160; The method can reduce both maintenance costs and flow uncertainty where Environmental Flow Release Monitoring is required.&lt;/p&gt;

The assessment of the physicochemical quality of water intended for irrigation of Oued Méskiana (Oum El Bouaghi) Algeria

The aquatic ecosystem of the Meskiana Valley (wilaya of Oum El Bouaghi) covers a large area with a permanent flow and a semi-arid climate characterized by a strong evapotranspiration. In order to determine the Physico-chemical quality, pollution and salinity of the water of the river of Meskiana and more particularly in its downstream part which is exposed to wastewater discharges, analyses were carried out at the level of three sampling points: witness, the upstream (before spill), downstream (after spill)). In order to prevent the risk of alkalization and salinization of soil, the sodium absorption rate (SAR) and the percentage of sodium were determined and represented on the Wilcox and Riverside diagram. The high concentrations of polluting chemical elements and excessive salinity obtained at the downstream site show a high risk of pollution and salinization.

Intertidal meiofaunal communities in relation to salinity gradients in the Ba Lai river, Vietnam

In order to reveal the characteristics of meiofaunal communities (MC) (specifically freshwater meiofauna) and its relationship with salinity gradients, meiofauna samples were collected in September 2015 in Ba Lai river (BLR), Mekong river, Vietnam. A total of 14 meiofaunal taxa were identified. The most dominant group was Nematoda, followed by Nauplii and Rotifera. The MC (specifically nematodes) in BLR were characterized by high abundances and diversities. The characteristics of MC in the downstream site (marine habitats) may be a considerable difference from those in the upstream site (fresh habitats). Abundances and diversities of nematode communities in the downstream site were much higher than observed in the upstream site, especially for abundances. Regarding MC, their abundance in the downstream site was also considerably higher than those in upstream site, whereas their diversity in the downstream site was lower than estimated in the upstream site. Furthermore, the Ba Lai dam (BLD) has the ability to change salinity gradients in BLR, while MC were a strong correlation with salinity. Therefore, the MC and their correlation with environmental variables can be considered as a good tool for the effects of dams on river’s ecosystems. Để xác định các đặc điểm của quần xã động vật đáy cỡ trung bình (đặc biệt là nhóm nước ngọt) và mối liên hệ giữa chúng với độ mặn, mẫu động vật đáy được thu thập vào tháng 09 năm 2015 trên sông Ba Lai, thuộc hệ thống sông Mekong, Việt Nam. Tổng cộng 14 nhóm động vật đáy được ghi nhận, ưu thế nhất là Nematoda, sau đó là Nauplii và Rotifera. Quần xã động vật đáy trên sông Ba Lai có mật độ và đa dạng cao và đặc điểm nhóm nước ngọt (trong đập Ba Lai) khác biệt với nhóm nước mặn (ngoài đập). Mật độ và đa dạng của nhóm Nematoda ngoài đập cao hơn trong đập. Trong khi đó, đa dạng quần xã động vật đáy trong đập cao hơn bên ngoài, mật độ thì ngược lại. Ngoài ra, đập Ba Lai làm biến đổi độ mặn trên sông Ba Lai, trong khi độ mặn có tương quan chặc chẽ với quần xã động vật đáy. Cụ thể, mật độ, đa dạng của quần xã tuyến trùng và mật độ của quần xã động vật đáy cỡ trung bình có tương quan thuận với độ mặn. Ngược lại, độ đa dạng quần xã động vật đáy cỡ trung bình có tương quan nghịch với độ mặn. Cho nên, quần xã động vật đáy có thể sử dụng làm chỉ thị cho tác động của đập chắn lên hệ sinh thái thủy vực.