The use of vibrational spectroscopy and supervised machine learning for chemical identification of plastics ingested by seabirds.

Plastic pollution is now ubiquitous in the environment and represents a growing threat to wildlife, who can mistake plastic for food and ingest it. Tackling this problem requires reliable, consistent methods for monitoring plastic pollution ingested by seabirds and other marine fauna, including methods for identifying different types of plastic. This study presents a robust method for the rapid, reliable chemical characterisation of ingested plastics in the 1-50 mm size range using infrared and Raman spectroscopy. We analysed 246 objects ingested by Flesh-footed Shearwaters (Ardenna carneipes) from Lord Howe Island, Australia, and compared the data yielded by each technique: 92 % of ingested objects visually identified as plastic were confirmed by spectroscopy, 98 % of those were low density polymers such as polyethylene, polypropylene, or their copolymers. Ingested plastics exhibit significant spectral evidence of biological contamination compared to other reports, which hinders identification by conventional library searching. Machine learning can be used to identify ingested plastics by their vibrational spectra with up to 93 % accuracy. Overall, we find that infrared is the more effective technique for identifying ingested plastics in this size range, and that appropriately trained machine learning models can be superior to conventional library searching methods for identifying plastics.

Antibiotic synergistic effect surge bioenergy potential and pathogen resistance of Chlorella variabilis biofilm.

Tetracycline (TC) and ciprofloxacin (CF) induce a synergistic effect that alters the biochemical composition, leading to a decrease in the growth and photosynthetic efficiency of microalgae. But the current study provides a novel insight into stress-inducing techniques that trigger a change in macromolecules, leading to an increase in the bioenergy potential and pathogen resistance of Chlorella variabilis biofilm. The study revealed that in a closed system, a light intensity of 167 µmol/m2/s causes 93.5% degradation of TC and 16% degradation of CF after 7 days of exposure, hence availing the products for utilization by C. variabilis biofilm. The resistance to pathogens invasion was linked to 85% and 40% increase in the expression level of photosystem II oxygen-evolving enhancer protein 3 (PsbQ), and mitogen activated kinase (MAK) respectively. The results also indicate that a surge in light intensity triggers 49% increase in the expression level of lysophosphatidylcholine (LPC) (18:2), which is an important lipidomics that can easily undergo transesterification into bioenergy. The thermogravimetric result indicates that the biomass sample of C. variabilis biofilm cultivated under light intensity of 167 µmol/m2/s produces a higher residual mass of 45.5% and 57.5 under air and inert conditions, respectively. The Fourier transform infrared (FTIR) indicates a slight shift in the major functional groups, while the energy-dispersive X-ray spectroscopy (SEM-EDS) and X-ray fluorescence (XRF) indicate clear differences in the morphology and elemental composition of the biofilm biomass in support of the increase bioenergy potential of C. variabilis biofilm. The current study provides a vital understanding of a innovative method of cultivation of C. variabilis biofilm, which is resistant to pathogens and controls the balance between fatty acid and TAG synthesis leading to surge in bioenergy potential and environmental sustainability.

Antibiotic residues and microbial contamination in pasteurized whole milk intended for human consumption.

Background and Aim: Milk contamination for human consumption is one of the biggest concerns worldwide. To prevent milk contamination, it is important to implement sustainable production practices that ensure animal health and guarantee veterinary drugs have been used properly. This study aimed to detect antibiotic residues and microbial contamination in commercially available pasteurized whole milk intended for human consumption. Materials and Methods: We conducted a cross-sectional study on all brands of pasteurized milk (n = 17) for human consumption in Medellín, Colombia, from February 30 to April 30, 2022. Six milk samples of each brand were collected every 15 days, resulting in 102 samples. IDEXX SNAPduo™ ST Plus test (IDEXX Laboratories Inc, Maine, USA) was used to detect cephalosporins residues to detect beta-lactam and tetracyclines. We detected mesophilic aerobic bacteria and coliforms using Chromocult Coliform Agar® (Merck KGaA, Darmstadt, Germany) and Plate-Count Agar® (Merck KGaA), respectively. Results: Beta-lactam residues were found in 24.4% of the brands. No tetracyclines or cephalosporins were detected. Mesophilic aerobic bacteria and coliform contamination were detected in 42.6% and 12.8% of the brands, respectively. No fecal coliform contamination was detected. Conclusion: This study demonstrated the presence of antibiotic residues and microbial contamination in commercially available pasteurized whole milk intended for human consumption in the study area, highlighting its potential public health implications.

Exploring the dynamics of algae-associated microbiome during the scale-up process of Tetraselmis sp. microalgae: A metagenomics approach.

Microalgae have become a key source of valuable compounds, promoting commercial scale applications. However, biological contamination is one of the most critical problems associated with large scale algal production, especially in open systems such as raceway ponds. The current research is the first to assess the effectiveness of open raceway ponds in maintaining a pure culture of Tetraselmis sp., starting from 20 L culture up to 10,000 L culture. Microbial profiling of each successive stage revealed lower abundance of eukaryotic organisms, whereas bacterial abundance increased notably resulting in a significant decrease in Tetraselmis sp. abundance. Furthermore, several bacteria with algae growth-promoting properties were found throughout the various culture stages including Balneola, Roseovarius, and Marinobacter. However, some algae-suppressive bacteria were evidenced at later stages such as Ulvibacter, Aestuariicoccus, and Defluviimonas. Overall, due to the increasing bacterial concentration, considerations limiting bacterial contamination need to be taken.

ASSESSMENT OF THE CONSEQUENCES OF THE DETERIORATION OF THE EPIDEMIOLOGICAL SITUATION DURING HOSTILITIES.

OBJECTIVE: The aim: Scientific substantiation of the methodology for predicting the consequences of the worsening of the epidemic situation on the territory of Ukraine during military operations for the timely adoption of measures for the medical protection of military personnel in conditions of biological contamination. PATIENTS AND METHODS: Materials and methods: Determination and generalization of the impact of biological contamination due to the use of biological weapons were carried out considering the main determinants of the epidemic process using the index and coefficient of medical protection. Applied methods of scientific research: epidemiological, system, and information approach. RESULTS: Results: The authors proposed indicators that consider the pathogenicity of the infectious agent, contagiousness, the degree of non-specific protection of servicemen, specific protection of servicemen, and the sanitary-epidemiological state of the area of operations of troops (forces). Relevant epidemic situations were simulated, and the index and coefficient of medical protection were calculated to predict the consequences of the worsening of the epidemic situation to make timely decisions regarding the implementation of medical protection measures for military personnel in conditions of biological contamination during the repulsion of armed aggression. CONCLUSION: Conclusions: In the conditions of biological contamination, when biological weapons and biological terrorism are used, the epidemic process in the army is intensified, which requires timely decisions regarding the implementation of medical protection measures for military personnel in conditions of biological contamination.

Interaction between microorganisms and dental material surfaces: general concepts and research progress.

Bacterial adhesion to dental materials' surfaces is the initial cause of dental materials-related infections. Therefore, inhibiting bacterial adhesion is a critical step in preventing and controlling these infections. To this end, it is important to know how the properties of dental materials affect the interactions between microorganisms and material surfaces to produce materials without biological contamination. This manuscript reviews the mechanism of bacterial adhesion to dental materials, the relationships between their surface properties and bacterial adhesion, and the impact of bacterial adhesion on their surface properties. In addition, this paper summarizes how these surface properties impact oral biofilm formation and proposes designing intelligent dental material surfaces that can reduce biological contamination.

A universal strategy for the construction of polymer brush hybrid non-glutaraldehyde heart valves with robust anti-biological contamination performance and improved endothelialization potential.

With the intensification of the aging population and the development of transcatheter heart valve replacement technology (THVR), clinical demand for bioprosthetic valves is increasing rapidly. However, commercial bioprosthetic heart valves (BHVs), mainly manufactured from glutaraldehyde cross-linked porcine or bovine pericardium, generally undergo degeneration within 10-15 years due to calcification, thrombosis and poor biocompatibility, which are closely related to glutaraldehyde cross-linking. In addition, endocarditis caused by post-implantation bacterial infection also accelerates the failure of BHVs. Herein, a functional cross-linking agent bromo bicyclic-oxazolidine (OX-Br) has been designed and synthesized to crosslink BHVs and construct a bio-functionalization scaffold for subsequent in-situ atom transfer radical polymerization (ATRP). The porcine pericardium cross-linked by OX-Br (OX-PP) exhibits better biocompatibility and anti-calcification property than the glutaraldehyde-treated porcine pericardium (Glut-PP) as well as comparable physical and structural stability to Glut-PP. Furthermore, the resistance to biological contamination especially bacterial infection of OX-PP along with anti-thrombus and endothelialization need to be enhanced to reduce the risk of implantation failure due to infection. Therefore, amphiphilic polymer brush is grafted to OX-PP through in-situ ATRP polymerization to prepare polymer brush hybrid BHV material SA@OX-PP. SA@OX-PP has been demonstrated to significantly resist biological contamination including plasma proteins, bacteria, platelets, thrombus and calcium, and facilitate the proliferation of endothelial cells, resulting in reduced risk of thrombosis, calcification and endocarditis. Altogether, the proposed crosslinking and functionalization strategy synergistically achieves the improvement of stability, endothelialization potential, anti-calcification and anti-biofouling performances for BHVs, which would resist the degeneration and prolong the lifespan of BHVs. The facile and practical strategy has great potential for clinical application in fabricating functional polymer hybrid BHVs or other tissue-based cardiac biomaterials. STATEMENT OF SIGNIFICANCE: Bioprosthetic heart valves (BHVs) are widely used in valve replacements for severe heart valve disease, and clinical demand is increasing year over year. Unfortunately, the commercial BHVs, mainly cross-linked by glutaraldehyde, can serve for only 10-15 years because of calcification, thrombus, biological contamination, and difficulties in endothelialization. Many studies have been conducted to explore non-glutaraldehyde crosslinkers, but few can meet high requirements in all aspects. A new crosslinker, OX-Br, has been developed for BHVs. It can not only crosslink BHVs but also serve as a reactive site for in-situ ATRP polymerization and construct a bio-functionalization platform for subsequent modification. The proposed crosslinking and functionalization strategy synergistically achieves the high requirements for stability, biocompability, endothelialization, anti-calcification, and anti-biofouling propeties of BHVs.

Avaliação parasitológica e microbiológica de areia de praias de São Luís, Maranhão, Brasil / Parasitological and microbiological evaluation of sand from beaches in São Luís, Maranhão, Brazil

O Brasil é um país que possui um litoral onde se deparam grandes cidades e com grande fluxo de atividades humanas, o que pode levar a contaminação por microrganismos e parasitos. Diante desse contexto, o objetivo desse trabalho foi avaliar a ocorrência parasitária e microbiológica em areia de praias de São Luís, Maranhão. Para tal, foram coletadas quatro amostras de três praias, totalizando assim 12 amostras, cada área foi dividida em quatro faixas distintas, sendo duas secas e duas úmidas, e para cada amostra foram introduzidos coletores estéreis na areia com profundidade de 20 centímetros. As amostras foram identificadas e colocadas em caixa de isopor e foram conduzidas ao laboratório para análises, a parasitológica foi através do método de sedimentação espontânea e centrifugação e para a microbiológica utilizou-se o kit COLItest® para determinação de coliformes totais e termotolerantes (Escherichia coli). As areias, 100% (12/12) encontravam-se positivas para helmintos e/ou protozoários, sendo que o helminto e protozoário de maior ocorrência foram: 100% (12/12) Trichuris trichiura e 83,3% (10/12) Giardia lamblia, respectivamente. As análises microbiológicas, apresentaram 66,6% (8/12) com contaminação por coliformes totais, e 58,3% (7/12) para Escherichia coli, o ponto de coleta 3 da areia seca da praia de São Marcos (Sm3S) apresentou a maior contaminação por Escherichia coli (4,33x102 UFC/mL). As praias da orla marítima chamada Litorânea em São Luís estão contaminadas por parasitas como também por bactérias oriundas de fontes que entraram em contato com fezes seja de animais ou de humanos. Assim, aumenta-se a probabilidade de indivíduos que frequentem esses ambientes de adquirirem infecções.

Brazil has a coastline with large cities and a great flow of human activities, which can lead to contamination by microorganisms and parasites. Given this context, the objective of this study was to evaluate the parasitic and microbiological events in the sand of beaches in São Luís, Maranhão. Therefore, four samples were collected from three beaches, thus totaling 12 samples. Each area was divided into four distinct segments, two dry and two wet, and for each sample, sterile collectors were inserted into the sand at a depth of 20 centimeters. The samples were identified, placed in a Styrofoam box, and taken to the laboratory for analysis. The parasitological analysis was performed through spontaneous sedimentation and centrifugation, while the microbiological analysis used the COLItest® kit to determine total and thermotolerant coliforms (Escherichia coli). All the sand samples were positive (100%) for helminths and/or protozoa, and the most frequent helminth and protozoan were Trichuris trichiura (100%; n=12 ) and Giardia lamblia (83.3%; n=10), respectively. Microbiological analyses showed that 66.6% (8/12) were contaminated by total coliforms and 58.3% (7/12) by Escherichia coli. Collection point 3 of dry sand from São Marcos beach (Sm3S) showed the highest contamination by Escherichia coli (4.33x102 CFU/mL). The beaches on the seafront called Litorânea in São Luís are contaminated by parasites and fecal bacteria from animals or human sources on the beach. Thus, the probability of acquiring infections increases among individuals visiting these environments.

A case study: The deployment of a novel in situ fluorimeter for monitoring biological contamination within the urban surface waters of Kolkata, India.

The quality and health of many of our vital freshwater systems are poor. To tackle this with ever increasing pressures from anthropogenic and climatic changes, we must improve water quality monitoring and devise and implement more appropriate water quality parameters. Recent research has highlighted the potential for Peak T fluorescence (tryptophan-like fluorescence, TLF) to monitor microbial activity in aquatic systems. The VLux TPro (Chelsea Technologies Ltd., UK), an in situ real-time fluorimeter, was deployed in different urban freshwater bodies within Kolkata (West Bengal, India) during March 2019. This study is the first to apply this technology in surface waters within a densely populated urban area. Spot-sampling was also undertaken at 13 sampling locations enabling physicochemical analysis, bacterial enumeration and determination of nutrient (nitrate and phosphate) concentrations. This case study has demonstrated the ability of an in situ fluorimeter, VLux TPro, to successfully identify both biological contamination events and potential elevated microbial activity, related to nutrient loading, in complex surface freshwaters, without the need for expensive and time-consuming laboratory analysis.

Reflection about the hemodialysis water microbiological quality in Brazil

Abstract Dialysis has been widely used in the treatment of patients with chronic kidney diseases and is considered a global public health issue. This treatment, which has changed the prognosis and quality of life in patients with chronic renal failure, can lead to complications that are often fatal. For this reason, there is a need for validation of alternative tests that favor the monitoring of treated water for dialysis in real-time to promote and prevent injuries to patients submitted to this procedure.

Contaminação microbiológica de resinas compostas utilizadas em uma clínica-escola de Odontologia / Microbiological contamination of composite resins used in a Dental school clinic

O objetivo desse estudofoi verificar a contaminação microbiológica deresinas compostas utilizadas em uma clínica-escola de Odontologia. Trata-se de uma pesquisa experimental/laboratorial, na qual foramcoletadas amostras de 10 bisnagas de resina composta, sendo uma delas o controle negativo. Porções de resina composta contidas no interior das bisnagas foram coletadas e mergulhadas em tubos de ensaio contendo caldo nutriente eposterior semeadura em placas e coloraçãopara caracterizar as colônias e observar bactérias e fungos. Todas as amostras apresentaram contaminação, inclusive o tubo contendo meio de cultura utilizado como controle de manuseio do experimento. Essas contaminações podem ter relação com as falhas dos meios de biossegurança empregados na clínica-escola e com os métodos de transporte e armazenamento das bisnagas de resina composta. Portanto, existe a necessidade de conscientização dos estudantese docentespara a adoção de medidas de biossegurança específicas para o manuseio das resinas compostas (AU).

The aim of this study was to verify the microbiological contamination in composite resins used at one Dental school clinic. This is an experimental/laboratory study, in which samples of 10 tubes of composite resin were collected, one of which was the negative control. Portions of composite resin inside the tubes were collected and dipped in test tubes containing nutrient broth for subsequent seeding on to plates and staining for the characterization of bacterial and fungal colonies. All samples revealed contamination, including the tube containing culture medium used as control for handling the experiment. These contaminations may be related to failures in biosafety measures employed in theDental school clinic and to the transport and storage methods for the tubes of composite resin. Therefore, it is necessary to raise awareness among students and teachers to adopt specific biosafety measures for the handling of composite resins (AU).

Effect of Saliva/Blood Contamination on Enamel Bond Strength / Efeito da Contaminação de Saliva/Sangue na Força de União ao Esmalte

Abstract In the routine clinical situation, the contamination by blood and/or saliva in restorative procedures can be happen in non-cooperation of the patient in dental office. The aim of the study was to assess in vitro shear bond strength of a resin sealant associated with two types of adhesives contaminated with saliva and blood. Healthy human molars were used and the specimens and the crowns were sectioned in the bucco-lingual direction, thus obtaining two segments of similar proportions (mesial and distal), totaling 60 surfaces, and the surfaces were randomly divided into 4 groups (n = 15). Group I (control) received no type of contamination and the sealant was applied. In group II, the surfaces were contaminated with 10 µl of saliva/blood and the sealant was applied. In group III, the surfaces were contaminated with 10 µl of saliva/blood and the Single Bond total-etch adhesive system was applied followed by application of sealant. In group IV, the surfaces were contaminated with 10 µl of saliva/blood and the Prime & Bond NT total-etch adhesive system was applied followed by the application of sealant. Samples were tested in the universal testing machine and the analysis of shear bond strength was performed. A difference between Group I (12.61MPa) and the other groups was found; Group II (2. 28MPa) was different than Groups III (7.07MPa) and IV (7.79MPa), but Groups III and IV were similar. The application of an adhesive system when there is contamination with saliva/blood is required prior to application of pit and fissure sealants. (AU)

Resumo Na situação clínica de rotina, a contaminação por sangue e/ou saliva em procedimentos restauradores pode ocorrer em pacientes que não colaboram no consultório odontológico. O objetivo do estudo foi avaliar a resistência ao cisalhamento in vitro de um selante de resina associado a dois tipos de adesivos contaminados com saliva e sangue. Foram utilizados molares humanos saudáveis e os espécimes e as coroas foram seccionados na direção bucal-lingual, obtendo assim dois segmentos de proporções semelhantes (mesial e distal), totalizando 60 superfícies, e as superfícies foram divididas aleatoriamente em 4 grupos (n = 15). O Grupo I (controle) não recebeu nenhum tipo de contaminação e o selante foi aplicado. No grupo II, as superfícies foram contaminadas com 10 µl de saliva / sangue e o selante foi aplicado. No grupo III, as superfícies foram contaminadas com 10 µl de saliva / sangue e o sistema adesivo Single-Bond foi aplicado seguindo a aplicação de selante. No grupo IV, as superfícies foram contaminadas com 10 µl de saliva / sangue e o sistema adesivo de ataque total Prime & Bond NT foi aplicado seguido da aplicação de vedante. As amostras foram testadas na máquina de ensaio universal e a análise da resistência à ligação ao cisalhamento foi realizada. Uma diferença entre o Grupo I (12,61MPa) e os outros grupos foi encontrada; O Grupo II (2,28 MPa) foi diferente dos Grupos III (7,07MPa) e IV (7,79 MPa), mas os Grupos III e IV foram semelhantes. A aplicação de um sistema adesivo quando existe contaminação com saliva / sangue é necessária antes da aplicação de selantes de fissura e fissura.

The role of bio-pollutants in the indoor air quality of old museum buildings: artworks biodeterioration as preview of human diseases.

Indoor air quality in buildings is strongly affected by chemical, physical, and biological agents. Long exposure to inadequate indoor air quality can be very dangerous for the building occupants and can lead to chronic diseases associated with the sick building syndrome (SBS). In this paper, the large presence of biological pollutants in the indoor rooms of an old building and its strict relationship with the outdoor/indoor air conditions were investigated studying Coronini Cronberg Palace Foundation, a historic house museum of the sixteenth century in Gorizia (Italy), where biological contamination affecting the artworks can soon become potentially harmful also for operators and visitors. Detailed aerobiological and microbiological analyses on organic natural materials, combined with a microclimate monitoring, were conducted to evaluate the influence of temperature and relative humidity levels within the Palace in the conspicuous growth and diffusion of microorganisms. Fungal and bacterial colonies damaging materials, mainly affected by the sudden fluctuations of hygrothermal values, were found to widely exceed Italian and international recommended levels for good air quality for both artworks and human beings. Understand their impact on human health would be strictly necessary to reduce biological risks for museum staff and cultural heritage users, but consequently to improve indoor air quality.

Overcoming the Biological Contamination in Microalgae and Cyanobacteria Mass Cultivations for Photosynthetic Biofuel Production.

Microalgae and cyanobacteria have shown significant potential for the development of the next biofuels innovation because of their own characteristics as photosynthetic microorganisms. However, it is confronted with a lot of severe challenges on the economic scaling-up of the microalgae- and cyanobacteria-based biofuels production. One of these major challenges is the lack of a reliable preventing and controlling culture system of biological contamination, which can attack the cell growth or product accumulation causing crashing effects. To increase the commercial viability of microalgae- and cyanobacteria-based biofuels production, overcoming the biological contaminations should be at the top of the priority list. Here, we highlight the importance of two categories of biological contaminations and their controlling strategies in the mass cultivations of microalgae and cyanobacteria, and outline the directions that should be exploited in the future.

Metabolic engineering of phosphite metabolism in Synechococcus elongatus PCC 7942 as an effective measure to control biological contaminants in outdoor raceway ponds.

BACKGROUND: The use of cyanobacteria and microalgae as cell factories to produce biofuels and added-value bioproducts has received great attention during the last two decades. Important investments have been made by public and private sectors to develop this field. However, it has been a challenge to develop a viable and cost-effective platform for cultivation of cyanobacteria and microalgae under outdoor conditions. Dealing with contamination caused by bacteria, weedy algae/cyanobacteria and other organisms is a major constraint to establish effective cultivation processes. RESULTS: Here, we describe the implementation in the cyanobacterium Synechococcus elongatus PCC 7942 of a phosphorus selective nutrition system to control biological contamination during cultivation. The system is based on metabolic engineering of S. elongatus to metabolize phosphite, a phosphorus source not normally metabolized by most organisms, by expressing a bacterial phosphite oxidoreductase (PtxD). Engineered S. elongatus strains expressing PtxD grow at a similar rate on media supplemented with phosphite as the non-transformed control supplemented with phosphate. We show that when grown in media containing phosphite as the sole phosphorus source in glass flasks, the engineered strain was able to grow and outcompete biological contaminants even when the system was intentionally inoculated with natural competitors isolated from an irrigation canal. The PtxD/phosphite system was successfully used for outdoor cultivation of engineered S. elongatus in 100-L cylindrical reactors and 1000-L raceway ponds, under non-axenic conditions and without the need of sterilizing containers and media. Finally, we also show that the PtxD/phosphite system can be used as selectable marker for S. elongatus PCC 7942 transgenic strains selection, eliminating the need of antibiotic resistance genes. CONCLUSIONS: Our results suggest that the PtxD/phosphite system is a stable and sufficiently robust strategy to control biological contaminants without the need of sterilization or other complex aseptic procedures. Our data show that the PtxD/phosphite system can be used as selectable marker and allows production of the cyanobacterium S. elongatus PCC 7942 in non-axenic outdoor reactors at lower cost, which in principle should be applicable to other cyanobacteria and microalgae engineered to metabolize phosphite.

Water and microbial monitoring technologies towards the near future space exploration.

Space exploration is demanding longer lasting human missions and water resupply from Earth will become increasingly unrealistic. In a near future, the spacecraft water monitoring systems will require technological advances to promptly identify and counteract contingent events of waterborne microbial contamination, posing health risks to astronauts with lowered immune responsiveness. The search for bio-analytical approaches, alternative to those applied on Earth by cultivation-dependent methods, is pushed by the compelling need to limit waste disposal and avoid microbial regrowth from analytical carryovers. Prospective technologies will be selected only if first validated in a flight-like environment, by following basic principles, advantages, and limitations beyond their current applications on Earth. Starting from the water monitoring activities applied on the International Space Station, we provide a critical overview of the nucleic acid amplification-based approaches (i.e., loop-mediated isothermal amplification, quantitative PCR, and high-throughput sequencing) and early-warning methods for total microbial load assessments (i.e., ATP-metry, flow cytometry), already used at a high readiness level aboard crewed space vehicles. Our findings suggest that the forthcoming space applications of mature technologies will be necessarily bounded by a compromise between analytical performances (e.g., speed to results, identification depth, reproducibility, multiparametricity) and detrimental technical requirements (e.g., reagent usage, waste production, operator skills, crew time). As space exploration progresses toward extended missions to Moon and Mars, miniaturized systems that also minimize crew involvement in their end-to-end operation are likely applicable on the long-term and suitable for the in-flight water and microbiological research.

Strategies to control biological contaminants during microalgal cultivation in open ponds.

Microalgal biomass is in great demand for many applications, including aquaculture feed. The most suitable system for microalgal culture is open pond cultivation, but it is also highly vulnerable to biological contamination. Contamination greatly reduces the biomass yield and depending on the contaminant, the quality of the biomass as a feed additive is compromised. Five groups of organisms that are the most common contaminants, including grazers, fungi, photosynthetic organisms, bacteria and viruses, are presented and the best possible ways to control these contaminants are indicated. Selection of a fast growing species along with selective technologies previously used for wastewater treatment can keep grazer population in control, while exploiting host-specific characteristic of fungal infection can protect from fungal attacks. Control of photosynthetic organisms and bacteria by good cultivation practices and the use of probiotics are critically important, as these organisms compete with the microalgal culture for sunlight and organic substrate.

Best practices for detecting and mitigating the risk of cell culture contaminants.

A variety of biological and chemical contaminants can adversely impact cells in culture, ranging from outright destruction of the culture, mutation, phenotypic changes to relatively minor changes in morphology, or growth rate. There are various approaches to detecting and mitigating the risk of biological or microbial contaminants in cell cultures, and these are discussed in this article. Chemical contaminants typically arise from improper handling or sourcing of cell culture reagents, glassware, or other types of consumables. These and other sources of chemical contaminants of cell cultures are discussed. The occurrence of chemical contamination is mitigated through adherence to best practices in sourcing and handling of such materials and by avoiding the use of volatile solvents within incubators that are used for maintaining cell cultures.

Microwave radiation is effective at disinfecting dental stone surfaces without changing their physical properties.

The aims of this study were to evaluate the effectiveness of different microwave radiation regimens for disinfection of type IV dental stone surfaces and to assess the influence of these regimens on surface roughness and dimensional change following disinfection. Three hundred cylindrical (20 × 2-mm) test specimens were made in type IV stone and divided into subgroups of 20 according to the microorganisms tested (Staphylococcus aureus, Escherichia coli, or Candida albicans) and the 900-W microwave radiation protocol (cycles of 3, 5, or 7 minutes; a positive control; or a negative control). To test physical changes, 80 test specimens were made with the same dimensions except that they had 2 parallel and symmetrical indentations measuring 8 × 4 mm. These specimens were divided into 4 subgroups of 20 each (a subgroup for each radiation time and a negative control). The mean dimensional change and roughness data were analyzed by mixed models for repeated measures and Tukey-Kramer tests. Disinfection was analyzed with descriptive statistics. For E coli and C albicans, all radiation times proved effective at sterilizing the test specimens. For S aureus, sterilization was achieved with 5 and 7 minutes of exposure; however, colonies were observed in 10 Petri dishes (50%) exposed to 3 minutes of microwave radiation. No statistically significant difference in dimensional change or surface roughness was observed for any radiation regimen (P > 0.05).

Potential of curcumin-mediated photodynamic inactivation to reduce oral colonization.

OBJECTIVE: The present study assessed the susceptibility of salivary pathogens to photodynamic inactivation (PDI), mediated by a water-soluble mixture of curcuminoids (CRM) and LED light. METHODS: A 10mL sample of unstimulated saliva was collected from volunteers. The inoculum was prepared using 9mL of saline and 1mL of saliva. Inoculum suspensions were divided into 14 groups and treated according to the description below. Groups that received the PDI treatment (light for 1min or 5min and 1.5g/L or 3.0g/L of CRM concentration) were called C1.5L1.8, C1.5L9.0, C3.0L1.8, C3.0L9.0. To evaluate the CRM decontamination alone, the C1.5/1,C1.5/5,C3.0/1 and C3.0/5 groups were assessed. Likewise, light alone was evaluated through the L1.8 and L9.0 groups. Chlorhexidine at 0.12% (CLX) for 1 or 5min was used for the positive control groups (CLX1 and CLX5, respectively); saline was used for 1 or 5min (CTR1, CTR5, respectively) for the negative control groups. After the tests, serial dilutions were performed, and the resulting samples were plated on blood agar in microaerophilic conditions. The number of colony forming units (CFU/mL) was determined and log10-transformed. Data were analyzed using a One-way Analysis of Variance with Welch correction, followed by the Games Howell's test (α=0.05). Log reduction (LR) measure for antimicrobial efficacy was also calculated using data from the CTR5 as untreated samples. RESULTS: The CHX5 showed the best antimicrobial result, followed by the CLX1. The antimicrobial effect of CRM was more pronounced when associated with light (PDI), but significantly lower than the CLX5 effect. The C3.0L9.0 protocol showed similar results to the CLX1. CONCLUSION: The results show that PDI with CRM at the studied concentrations is as effective for oral decontamination in clinical dental care conditions as the CLX at 0.12% for 1min.