Artificial Aquatic Environments Research Articles

Insights into the structural features and phylogenetic implications of the complete mitochondrial genome of Fasin rainbow fish (Melanotaenia fasinensis).

The Fasin rainbow fish, scientifically named Melanotaenia fasinensis, is highly prized by aquarium enthusiasts for its vibrant colors and adaptability to artificial aquatic environments. This species is endemic to the karst landscape of the Bird's Head region in Papua, Indonesia, and belongs to the family Melanotaeniidae. Discovered relatively recently in 2010, this species was designated as endangered by the International Union for Conservation of Nature (IUCN) in 2021. However, there is currently insufficient data regarding its phylogenetic position. To address this gap, our study employed next-generation sequencing (NGS) to analyze the entire mitochondrial genome of M. fasinensis. The mitochondrial genome comprises 13 protein-coding genes, 22 transfer RNA genes, and two ribosomal RNA genes, with a total length of 16,731 base pairs. The base composition of the mitogenome revealed percentages of 27.76% adenine (A), 27.34% thymine (T), 16.15% guanine (G), and 28.75% cytosine (C) residues. Our phylogenetic analysis based on sequence data indicated that all species of the Melanotaeniidae family clustered together on the same branch. Furthermore, the intergeneric and interspecific taxonomic positions were explicit and clear. Phylogenetically, Melanotaeniidae were more closely related to the family Isonidae than to the family Atherinomorus. The phylogenetic position of M. fasinensis was relatively basal within the genus Melanotaenia. This study provides valuable molecular insights for further exploration of the phylogeography and evolutionary history of M. fasinensis and other members of the genus Melanotaenia.

Genetic Diversity of Legionella pneumophila Isolates from Artificial Water Sources in Brazil

Legionella pneumophila (Lp) is a Gram-negative bacterium found in natural and artificial aquatic environments and inhalation of contaminated aerosols can cause severe pneumonia known as Legionnaires’ Disease (LD). In Brazil there is hardly any information about this pathogen, so we studied the genetic variation of forty Legionella spp. isolates obtained from hotels, malls, laboratories, retail centers, and companies after culturing in BCYE medium. These isolates were collected from various sources in nine Brazilian states. Molecular identification of the samples was carried out using Sequence-Based Typing (SBT), which consists of sequencing and analysis of seven genes (flaA, pilE, asd, mip, mompS, proA, and neuA) to define a Sequence Type (ST). Eleven STs were identified among 34/40 isolates, of which eight have been previously described (ST1, ST80, ST152, ST242, ST664, ST1185, ST1464, ST1642) and three were new STs (ST2960, ST2962, and ST2963), the former identified in five different cooling towers in the city of São Paulo. The ST1 that is widely distributed in many countries was also the most prevalent in this study. In addition, other STs that we observed have also been associated with legionellosis in other countries, reinforcing the potential of these isolates to cause LD in Brazil. Unfortunately, no human isolates could be characterized until presently, but our observations strongly suggest the need of surveillance implementation system and control measures of Legionella spp. in Brazil, including the use of more sensitive genotyping procedures besides ST.

Bioaerosol Emission from Vortex Liquids Contaminated with Escherichia coli Bacteria

Vortex fluids are often present in natural and artificial aquatic environments and are also widely used in industrial water treatment and product manufacturing processes. Vortex processes have been studied quite extensively; however, little attention has been paid to the potential release of biological aerosols to the ambient air in common situations involving microbial-contaminated vortex liquids. The model organism was Escherichia coli, a common Gram-negative coliform bacterium widely present in the aquatic and air environments. This study examines the influence of various parameters, including liquid rotation speed, column height, temperature, surface tension and vessel size, on the rate of bioaerosol formation. A commonly used single-stage bioaerosol impactor was employed to collect microbial aerosols at different process parameters under controlled laboratory conditions. The main results show that bioaerosol production increases markedly with increasing rotation speed, reaching a maximum rate at the highest value used in this project (1300 rpm). The tallness of the liquid column is strongly responsible for the bioaerosol production efficiency reaching a difference of almost one order of magnitude along the range between 45 mm (highest bioaerosol release) and 110 mm used in this research. Fluid temperature and surface tension are also very influential parameters responsible for bioaerosol generation during fluid vortex motion; corresponding results are discussed in this manuscript.

Assessment of macrolide susceptibility of Legionella pneumophila isolated from public buildings' water systems in Turkiye.

Legionella pneumophila (Lp) is aerobic, non-spore forming Gram-negative bacteria, which is ubiquitous in freshwater habitats, such as rivers and hot springs, as well as colonizing artificial aquatic environments. The ability of Lp to grow intracellularly within pulmonary macrophages is a prerequisite for the development of infection. Therefore, macrolides can achieve appropriate therapeutic concentrations in eukaryotic cells, such as azithromycin. This study aimed to investigate the macrolides susceptibility of Lp. Pre-flash water samples (n=143) were collected from the public buildings (hospitals and hotels) water system in Istanbul. Colonies were confirmed as Lp ST1, ST2-14, and non-pneumophila Lp using latex agglutination kit. 30 Lp were detected in hospital (n=23) and hotel (n=7) water systems using latex agglutination. Regardless of serotype and excluding strains without zone formation (≥256 mg/L), the main MIC values of azithromycin, erythromycin and clarithromycin were 0.61 mg/L (range 0.047-1 mg/L), 0.47 mg/L (range 0.047-1 mg/L) and 0.44 mg/L (range 0.047-1 mg/L), respectively. The MIC50 and MIC90 values for macrolides were 0.5 and 3 mg/L for azithromycin, respectively; 0.38 and 1 mg/L for erythromycin, respectively; and 0.5 and 1 mg/L for clarithromycin, respectively. We compared the MIC values of the strains for all antimicrobial agents tested without serotype discrimination. We did not find a significant difference between the MIC values of the antibiotics (p=0.16). Although the data obtained from our study do not fully reflect the breakpoints, further epidemiological studies are needed to standardize MIC values.

Surface Measure to Depth (SMeTD): a new low-budget system for 3D water temperature measurements for combining with UAV-based thermal infrared imagery

Characterising spatial patterns in water temperature is important for monitoring aquatic habitats and understanding physical and biogeochemical processes to support environmental management decisions. As freshwater bodies exhibit high spatial and temporal variability, high-resolution 3D temperature data are essential to understand local anomalies. The acquisition of simultaneously high spatial and temporal datasets in the field has so far been limited by costs and/or workload associated with commonly used monitoring systems.We present a new, low-cost, spatially and temporally flexible 3D water temperature monitoring system, Surface Measures to Depth (SMeTD). SMeTD can be used to provide information on the relation of water surface temperature to changes with depth, characterise water temperature in 3D and ground truth remotely sensed thermal infrared data. The systems performance was tested under laboratory conditions and under controlled conditions in the field. This revealed an accuracy comparable to established but more expensive monitoring systems. Field testing of SMeTD involved 1-min data collection of 3D water temperature for a full diurnal cycle in a lake. The 3D temperature patterns were supported by a thermal infrared image of the lakes surface. The field dataset demonstrated higher water temperatures and higher water temperature variation at the surface compared to deeper layers. SMeTD can be used to observe a broad range of hydrological processes in natural and artificial aquatic environments and help to understand processes involved with energy budgets, infiltration, limnology, or groundwater surface water exchange.

Altering Fish Behavior by Sensing Swarm Patterns of Fish in an Artificial Aquatic Environment Using an Interactive Robotic Fish.

Numerous studies have been conducted to prove the calming and stress-reducing effects on humans of visiting aquatic environments. As a result, many institutions have utilized fish to provide entertainment and treat patients. The most common issue in this approach is controlling the movement of fish to facilitate human interaction. This study proposed an interactive robot, a robotic fish, to alter fish swarm behaviors by performing an effective, unobstructed, yet necessary, defined set of actions to enhance human interaction. The approach incorporated a minimalistic but futuristic physical design of the robotic fish with cameras and infrared (IR) sensors, and developed a fish-detecting and swarm pattern-recognizing algorithm. The fish-detecting algorithm was implemented using background subtraction and moving average algorithms with an accuracy of 78%, while the swarm pattern detection implemented with a Convolutional Neural Network (CNN) resulted in a 77.32% accuracy rate. By effectively controlling the behavior and swimming patterns of fish through the smooth movements of the robotic fish, we evaluated the success through repeated trials. Feedback from a randomly selected unbiased group of subjects revealed that the robotic fish improved human interaction with fish by using the proposed set of maneuvers and behavior.

Dissimilatory nitrate reduction processes in surface sediments of shrimp ponds during the culture period

Intensive aquaculture in estuaries and coasts has resulted in several ecological and environmental problems. Among various nitrogen transformation pathway, dissimilatory nitrate (NO3-) reduction is considered to be highly important in regulating reactive nitrogen. However, there are relatively few studies on the processes and contribution of NOx- reduction in sediment during the shrimp pond culture period. Three sediment NO3- reduction processes, denitrification (DNF), anaerobic ammonium oxidation (ANA), and dissimilatory NO3- reduction to ammonium (DNRA), were surveyed in eight shrimp ponds across three subtropical estuaries using 15N isotope tracing experiments. The rates of DNF, ANA and DNRA ranged from 2.87–18.11, 0.10–1.92, and 0.21–1.25 nmol N g -1 h -1, respectively. DNF was responsible for 64.2–91.6% of the total NO3- reduction. Regarding environmental factors, C and N substrates, as well as salinity, significantly affected NO3- reduction. In general, the N losses were approximately 32.43–131.64 g N m-2 yr-1 for DNF and 2.38–15.85 g N m-2 yr-1 for ANA in this study, indicating that coastal reclamation is a nonnegligible way to remove nitrogen. Our results provide a scientific foundation for understanding the mechanism of nitrogen cycling in the artificial aquatic environment of shrimp ponds.

An Insight into the Microbiology, Epidemiology, and Host Cell Biology of Legionella Pneumophila: A Review of Literature

Legionnaires’ disease (LD) is a type of severe pneumonia that mainly caused by bacteria of the genus Legionella. LD bacteria reside in the water systems of facilities where lack of water exchange or flow plays a crucial role in enhancing bacterial growth. The under-recognition of the dangers of Legionella along with easing of Coronavirus disease 2019 (COVID-19) lockdown restrictions and global reopening, pose a potential increased risk of developing LD. Various Legionella species can lead to legionellosis infections, including LD and Pontiac fever. Legionellosis cases is generally found in natural or artificial aquatic environments such as cooling towers, hot water tanks, or air conditioning. The bacteria elude the host’s immune responses by various strategies, including releasing effector proteins. Thus, this review provides insight into the microbiology, epidemiology, and host cell biology of L. pneumophila, as well as an emphasis on the bacterial novel survival strategies of L. pneumophila. Also, suggests taking intensive actions towards closed buildings as a potential source of bacterial infection.

Prerequisites for the development of biotechnology for the production of environmentally friendly products of aquabioculture

Aquaponics is a hybrid food growing technology that combines the best of aquaculture (growing fish in an artificial aquatic environment and hydroponics (growing plants without soil in an aquatic nutrient environment). It is completely organic because the fish produces natural fertilizers used by the plants, which means no exogenous chemicals. Aquaculture has been around for a long time. Throughout the civilized world, aquaculture is one of the most dynamically developing industries, it is considered as a way to ensure food security and a means to combat poverty. Due to the need to provide the world population with high-quality and healthy fish and vegetable products, aquaponics, which is already one of the fastest growing agricultural and food sectors, has great potential for future development.

Evaluation of water quality index in some artificial aquatic environments in Port Harcourt, Rivers State, Nigeria

Background and Objective: This study aimed at using application of Water Quality Index (WQI) in evaluating the quality status of some artificial aquatic environments (concrete, earthen and plastic fish tanks/pond) in Roone Fish Farm, Port Harcourt, Rivers State, Nigeria were studied from October 2018 to September 2019. Methodology: Nine water quality parameters were considered and some samples were measured in-situ (Temperature, pH, conductivity (EC), total dissolved solid (TDS), turbidity, dissolved oxygen (DO) while biological oxygen demand (BOD), nitrate (NO3) and phosphate (PO4) were analyzed in the laboratory following standard methods. Results: The results obtained were subjected to Minitab version 16 and Tukey’s comparison test was also employed to separate means. The water quality index (WQI) calculation used the mean values of the nine (9) parameters chosen using the standards recommended by the World Health Organization (WHO), Bureau of Indian Standards (BIS) and Indian Council for Medical Research (ICMR) for drinking water quality. The water quality indices for concrete fish tank, earthen fish pond and plastic fish tank were 60.24, 73.34 and 70.20 respectively. Though, earthen fish ponds had higher WQI value and would have considered very poor water with regard to WQI calculation. The values of the WQI revealed that all the three artificial aquatic environments (concrete, earthen and plastic pond/tanks) were considered to be poor water quality. Conclusion and Recommendations: It was concluded that WQI is used as a tool for communicating information on the status of quality in different water bodies despite their medium and purpose of use. It was also recommended that the three artificial aquatic environments water should be monitored regularly and may be treated before use to avoid related public health issues.

АВТОМАТИЗАЦІЯ УПРАВЛІННЯ ВОДНИМИ МІКРОЕКОСИСТЕМАМИ

The work is intended to stimulate the interest in the field of automation of livestock farms, improve the quality of management of aquatic ecosystems by automating the processes that occur in their habitat, in particular in the aquatic environment of exotic fish – aquariums. Before creating such an automated system, a number of ready-made solutions have been investigated, as well as methods for their design and synthesis have been studied. The research of existing developments and finished systems has shown that at the heart of such devices there are bulky systems sharpened under each individual aquarium. Based on the results of the study, it is decided to create a unified device, with a simple interface that would be suitable for all ordinary types of aquariums, without special preadjusting of the system under a separate artificial aquatic environment. Comparing the available and popular tools for rapid prototyping of microcontrollers, it is decided to focus on the Arduino platform. The great attention and interest in the platform of radio amateurs and professionals, and, based on the previous statement, the high prevalence of prefabricated modules and components for the platform have helped to make the right choice of the basis of an automated system for managing artificial aquatic ecosystems habitat. In the process of reviewing ready-made solutions in the market, systematization of the received data and studying the relevant specialized literature, the algorithm of work of the future device has been drawn up, the necessary elements for the system construction have been selected, the schematic diagram of the device has been modeled and the device has been assembled and tested on available aquarium. Testing of the synthesized system on a real reservoir with organisms proves the urgency of creating such an autonomous control device, because the state of the environment has been maintained exactly as programmed by the system. Responding to changing the state of the components of the aquatic environment with a number of sensors, the system manages the system devices themselves, thereby maintaining the desired balance of the aquarium with minimizing the human factor.

Are pharmaceuticals removal and membrane fouling in electromembrane bioreactor affected by current density?

Pharmaceutical active compounds (PhACs) have been detected at significant concentrations in various natural and artificial aquatic environments. In this study, electro membrane bioreactor (eMBR) technology was used to treat simulated municipal wastewater containing widely-used pharmaceuticals namely amoxicillin (AMX), diclofenac (DCF) and carbamazepine (CBZ). The effects of varying current density on the removal of PhACs (AMX, DCF and CBZ) and conventional pollutants (chemical oxygen demand (COD), dissolved organic carbon (DOC), humic substances, ammonia nitrogen (NH4-N), nitrate nitrogen (NO3-N) and orthophosphate (PO4-P) species) were examined. High COD and DOC removal efficiencies (~100%) were obtained in all the experimental runs regardless of applied current density. In contrast, enhanced removal efficiencies for AMX, DCF and CBZ were achieved at high current densities. Membrane fouling rate in eMBR with respect to conventional MBR was reduced by 24, 44 and 45% at current densities of 0.3, 0.5 and 1.15 mA/cm2, respectively. The mechanism for pharmaceutical removal in this study proceeded by: (1) charge neutralization between negatively-charged pharmaceutical compounds and positive electro-generated aluminium coagulants to form larger particles and (2) size exclusion by membrane filtration.

Attenuated Legionella pneumophila Survives for a Long Period in an Environmental Water Site.

Legionella pneumophila is known as a human pathogen and is ubiquitous in natural and artificial aquatic environments. Many studies have revealed the virulence traits of L. pneumophila using clinical strains and a number of studies for characterizing environmental strains are also reported. However, the association between the virulence and survivability in the environment is unclear. In the present study, L. pneumophila was isolated from environmental water sites (Ashiyu foot spa, water fountain, and public bath), and the serogroups of isolated strains were determined by serological tests. Isolated strains were found to belong to serogroups SG1, SG2, SG3, SG4, SG5, SG8, SG9, and SG13. Untypeable strains were also obtained. Isolated strains were used for intracellular growth assay in a human monocytic cell line, THP-1. Among these strains, only an untypeable strain, named AY3, failed to replicate in THP-1. In addition, AY3 was maintained for a long period in an environmental water site, Ashiyu foot spa 2. Further, we compared the characteristics of several strains isolated from Ashiyu foot spa 2 and a clinical strain, Togus-1. AY3 failed to replicate in THP-1 cells but replicated in an amoeba model, Dictyostelium discoideum. Compared with Togus-1, the culturable cell number of environmental strains under stress conditions was higher. Moreover, biofilm formation was assessed, and AY3 showed the same degree of biofilm formation as Togus-1. Biofilm formation, replication in amoebae, and resistance against stress factors would explain the predominance of AY3 at one environmental site. Although the mechanism underlying the difference in the ability of AY3 to replicate in THP-1 cells or amoebae is still unclear, AY3 may abandon the ability to replicate in THP-1 cells to survive in one environment for a long period. Understanding the mechanisms of L. pneumophila in replication within different hosts should help in the control of Legionnaires' disease, but further study is necessary.

Epidemiological trends of Reported Legionnaires’ disease in Houston, Texas, 2014-2017

OnjectiveTo study trends and patterns in legionnaires’ disease cases in Houston, Texas, from 2014-2017.IntroductionLegionellosis is a respiratory illness that is mostly (80-90%) caused by the bacterium Legionella pneumophila. It is associated with a mild febrile illness, Pontiac fever, or Legionnaires’ disease (1), a source of severe, community-acquired pneumonia. Legionella bacteria mostly affect elderly persons specifically those with underlying debilitating illnesses and with lowered immune systems. Water is the major natural reservoir for Legionella, and the pathogen is found in many different natural and artificial aquatic environments such as cooling towers or water systems in buildings, including hospitals. An abrupt increase in the incidence of Legionnaires’ has been noted since 2003 throughout the nation. According to CDC, about 6,000 cases of Legionnaires’ disease were reported in the United State in 2015 (1). Incidence rates of Legionnaires for the year 2015 were 1.06 and 1.90 (ref) for Texas and the United States respectively (2). Increased number of reported cases might be due to the fact of an older population, more at risk individuals, aging plumbing infrastructure, and increased testing for Legionnaires’ disease by various hospitals and laboratories.MethodsData were extracted from Houston’s Electronic Disease Surveillance System (HEDSS) from January 1, 2014, to December 07, 2018. Confirmed cases were analyzed to examine the epidemiologic trends across years 2014 to 2018. Demographic characteristics such as age, race, and gender were also analyzed. Incidence rates, case fatality and time lapse from date of diagnosis to date of reporting to the health department were also studied. Data were analyzed using SAS statistical software, version 9.4. Only Houston residents were included in the analysis. To be considered confirmed, a case must be clinically compatible and fulfill at least one of the confirmatory laboratory criteria.ResultsThere were 218 cases of LD reported to the City of Huston from 2014 to 2018. Only 116 cases (53%) were classified as confirmed. Reported cases may have been not confirmed due to the lack of fulfilling the case criteria for the case. Providers may have ordered a non-confirmative test, or the case may not have satisfied the clinical compatibility due to loss to follow-up or for other reasons.Most of the confirmed cases were reported from larger for-profit hospitals (500+beds) in the area. The majority of cases were diagnosed by urinary antigen test (95, 82%). There were four deaths due to legionnaires disease during this period giving a case fatality rate of 3.4%. Death rates were inaccurate, though, and could be higher than reported since cases were not followed up after being reported to the state. From 2014 to 2018, legionnaires’ disease incidence rates increased from 0.71 to 1.36 per 100,000, an average annual increase of 17%.In 2014–2018, the incidence of LD was higher among men compared with women. 67 cases (58%) were male, and 49 (42%) were female. Female cases remained stable throughout the years while male cases increased from 6 to 23, an increase of approximately four folds. The median age was 60 years with a range of 21 to 96 years. LD incidence increased with age; it was highest among residents 65 years and older (42,36%). African Americans had the highest incidence of LD (40, 35%) followed by Hispanics (29, 25%). African Americans cases had more than doubled through years 2014-2018 from 6 to 13. Cases were higher in warmer months specifically in July (14) an August (13).ConclusionsCases were higher in the warmer months and the highest among the elderly, men, and those of African American race. ELR was the prime source of initial case reporting to the health department. The number of legionnaire’s cases observed were increasing with each passing year. The ratio of confirmed cases to those reported were only 53% thus raising awareness and appropriate education to the investigators and providers are highly advised. It is critical to the control of LD that enhanced surveillance is maintained at a high level. Consequently, more consideration should be given for the more widespread use of Legionnaires confirming test when a patient presents with pneumonia.Hospitals and other healthcare facilities often have large, complex water systems, making them potentially high-risk settings for transmission of legionellosis to vulnerable patients or residents. We recommend all healthcare facilities have a water management program to control Legionella.

Exclusion of fish and invertebrates from benthic patches of artificial aquatic environments across water conductivity levels using high-frequency (10 Hz) pulses and adjustable electrical settings

Livestock fence chargers are often used to generate pulsed electrical fields in freshwater environments to exclude fish and invertebrates from benthic patches so that their ecological function can be investigated. Such devices appear to be effective, but the precise characteristics of the electrical fields they generate and specific settings needed to exclude organisms across water conductivity levels have not been described. We present an electrical engineering and experimental framework to predict and evaluate the effectiveness of a modified device at different combinations of electrical settings and water conductivities. We avoided toxic materials and considered safety issues. We conducted laboratory experiments to identify the electrical fields with a 10-Hz pulse frequency needed to exclude adult Fathead Minnows (Pimephales promelas) and crayfish (Procambarus clarkii) from electrical exclosures across a range of water conductivities (13–800 µS/cm). Fish and crayfish in waters of low conductivity (≤50 µS/cm) were excluded from exclosures at ≥200 V of electric potential. In water of higher conductivity (≥250 µS/cm), similar settings caused consumer immobilization. Electrical pulse durations of 150 µs were more effective than 50-µs pulse durations at excluding organisms. Further refinement toward standardized methods requires analogous experimentation in the field, but our findings emphasize the importance of comprehensively considering electrical fields (voltage, pulse frequency and duration), water conductivity, and electrode configuration a priori when using these devices to optimize designs.

Mutations in Novel Lipopolysaccharide Biogenesis Genes Confer Resistance to Amoebal Grazing in Synechococcus elongatus.

In natural and artificial aquatic environments, population structures and dynamics of photosynthetic microbes are heavily influenced by the grazing activity of protistan predators. Understanding the molecular factors that affect predation is critical for controlling toxic cyanobacterial blooms and maintaining cyanobacterial biomass production ponds for generating biofuels and other bioproducts. We previously demonstrated that impairment of the synthesis or transport of the O-antigen component of lipopolysaccharide (LPS) enables resistance to amoebal grazing in the model predator-prey system consisting of the heterolobosean amoeba HGG1 and the cyanobacterium Synechococcus elongates PCC 7942 (R. S. Simkovsky et al., Proc Natl Acad Sci U S A 109:16678-16683, 2012,http://dx.doi.org/10.1073/pnas.1214904109). In this study, we used this model system to identify additional gene products involved in the synthesis of O antigen, the ligation of O antigen to the lipid A-core conjugated molecule (including a novel ligase gene), the generation of GDP-fucose, and the incorporation of sugars into the lipid A core oligosaccharide ofS. elongatus Knockout of any of these genes enables resistance to HGG1, and of these, only disruption of the genes involved in synthesis or incorporation of GDP-fucose into the lipid A-core molecule impairs growth. Because these LPS synthesis genes are well conserved across the diverse range of cyanobacteria, they enable a broader understanding of the structure and synthesis of cyanobacterial LPS and represent mutational targets for generating resistance to amoebal grazers in novel biomass production strains.

Serological and molecular identification of Legionella spp. isolated from water and surrounding air samples in Italian healthcare facilities

BackgroundLegionella is an intracellular microorganism living in natural and artificial aquatic environments. Although its transmission to humans is linked to the inhalation of contaminated aerosols, there is no validated air sampling method for the control and prevention of the disease. The aim of the present study was to provide more information on the distribution of Legionella spp. in indoor environments and to determine whether the same Legionella strains are isolated from air and water samples. MethodsTen healthcare facilities located in seven regions of Italy were enrolled. The serological typing of Legionella spp. from water samples and the surrounding air by active and passive sampling was assessed using polyvalent and monovalent antisera. Subsequently, the strains identified as Legionella pneumophila (Lpn) underwent molecular typing by sequence-based typing (SBT) using seven genes (flaA, pilE, asd, mip, mompS, proA, and neuA). The allelic profile number was assigned using the European Working Group for Legionella Infections–SBT database. ResultsLpn serogroup 6 was the most prevalent serogroup; it was found simultaneously in the air and water samples of three different healthcare facilities. In the remaining seven hospitals, Lpn serogroups 1, 6, 7, 9, and 12 were isolated exclusively from water samples. The molecular investigation showed that Lpn strains in the water and air samples of each positive healthcare facility had the same allelic profile. Strains, identified as sequence types (STs) 728 and ST 1638+ST 1324, were isolated in two respective healthcare facilities, and a new strain, identified as ST 1989, was obtained in one healthcare facility. ConclusionThe application of the SBT method allowed to verify the homology among Legionella strains from water samples and the surrounding air. The results showed that the same Lpn strains were present in the air and water samples, and a new Legionella strain was identified.

Anti-cancer Parasporin Toxins are Associated with Different Environments: Discovery of Two Novel Parasporin 5-like Genes.

Cry toxins are primarily a family of insecticidal toxins produced by the bacterium Bacillus thuringiensis (Bt). However, some Cry toxins, called parasporins (PSs), are non-insecticidal and have been shown to differentially kill human cancer cells. Based on amino acid homology, there are currently six different classes of parasporins (PS1-6). It is not known what role parasporins play in nature, nor if certain PSs are associated with Bt found in particular environments. Herein, we present ten parasporin-containing isolates of Bt from the Caribbean island of Trinidad. Genes coding for PS1 and PS6 were found in isolates associated mainly with artificial aquatic environments (e.g., barrels with rain water), while Bt possessing two novel PS5-like genes (ps5-1 and ps5-2), were isolated from manure collected directly from the rectum of cattle. The amino acid sequences inferred from the two PS5-like genes were 51% homologous to each other, while being only 41 or 45% similar to PS5Aa1/Cry64Aa, the only reported member of the parasporin five class. The low level of amino acid homology between the two PS5-like genes and PS5Aa1 indicate that the two PS5-like genes may represent a new class of parasporins, or greatly expand the level of diversity within the current parasporin 5 class.

Investigating microbial transformations of soil organic matter: synthesizing knowledge from disparate fields to guide new experimentation

Abstract. Discerning why some soil organic matter (SOM) leaves soil profiles relatively quickly while other compounds, especially at depth, can be retained for decades to millennia is challenging for a multitude of reasons. Simultaneous with soil-specific advances, multiple other disciplines have enhanced their knowledge bases in ways potentially useful for future investigations of SOM decay. In this article, we highlight observations highly relevant for those investigating SOM decay and retention but often emanating from disparate fields and residing in literature seldom cited in SOM research. We focus on recent work in two key areas. First, we turn to experimental approaches using natural and artificial aquatic environments to investigate patterns of microbially mediated OM transformations as environmental conditions change, and highlight how aquatic microbial responses to environmental change can reveal processes likely important to OM decay and retention in soils. Second, we emphasize the importance of establishing intrinsic patterns of decay kinetics for purified substrates commonly found in soils to develop baseline rates. These decay kinetics – which represent the upper limit of the reaction rates – can then be compared to substrate decay kinetics observed in natural samples, which integrate intrinsic decay reaction rates and edaphic factors essential to the site under study but absent in purified systems. That comparison permits the site-specific factors to be parsed from the fundamental decay kinetics, an important advance in our understanding of SOM decay (and thus persistence) in natural systems. We then suggest ways in which empirical observations from aquatic systems and purified substrate–enzyme reaction kinetics can be used to advance recent theoretical efforts in SOM-focused research. Finally, we suggest how the observations in aquatic and purified substrate–enzyme systems could be used to help unravel the puzzles presented by oft-observed patterns of SOM characteristics with depth, as one example of the many perplexing SOM-related problems.

Legionella prevalence in wastewater treatment plants of Taiwan

Legionella is a bacterium that is ubiquitous in natural and artificial aquatic environments. Some species of Legionella are recognized as opportunistic potential human pathogens. We investigated the distribution of Legionella at seventeen WWTPs throughout Taiwan. Legionella were detected in 10 of the 17 WWTPs (58.8%) and 25 of 41 samples (61.0%). In the integrated, hospital, industrial and domestic wastewater systems were 13/18 (72.2%), 7/12 (58.3%), 2/7 (28.6%) and 3/4 (75.0%) of the samples were positive for Legionella, respectively. The most frequently encountered species were L. donaldsonii and uncultured L. spp., which were both found in 10 samples (24.4% of all samples), then followed by L. lytica (4.9%) and L. pneumophila (4.9%). L. anisa was detected in one sample (2.4%). The results of this survey confirm that Legionella are ubiquitous in WWTPs in Taiwan. Therefore, long-term investigations should be conducted to evaluate the overall occurrence of Legionella in WWTPs in Taiwan.