Influence of high gas production during thermophilic anaerobic digestion in pilot-scale and lab-scale reactors on survival of the thermotolerant pathogens Clostridium perfringens and Campylobacter jejuni in piggery wastewater

Safe reuse of animal wastes to capture energy and nutrients, through anaerobic digestion processes, is becoming an increasingly desirable solution to environmental pollution. Pathogen decay is the most important safety consideration and is in general, improved at elevated temperatures and longer hydraulic residence times. During routine sampling to assess pathogen decay in thermophilic digestion, an inversely proportional relationship between levels of Clostridium perfringens and gas production was observed. Further samples were collected from pilot-scale, bench-scale thermophilic reactors and batch scale vials to assess whether gas production (predominantly methane) could be a useful indicator of decay of the thermotolerant pathogens C. perfringens and Campylobacter jejuni. Pathogen levels did appear to be lower where gas production and levels of methanogens were higher. This was evident at each operating temperature (50, 57, 65 °C) in the pilot-scale thermophilic digesters, although higher temperatures also reduced the numbers of pathogens detected. When methane production was higher, either when feed rate was increased, or pH was lowered from 8.2 (piggery wastewater) to 6.5, lower numbers of pathogens were detected. Although a number of related factors are known to influence the amount and rate of methane production, it may be a useful indicator of the removal of the pathogens C. perfringens and C. jejuni

Monitoreo de la aplicación de vinaza como fertilizante en caña de azúcar con indicadores microbianos de suelo = Monitoring the application of vinasse as fertilizer of sugarcane with soil microbial indicators

En la última década se ha experimentado un importante cambio en el sistema energético mundial hacia el uso de biocombustibles. En Uruguay, el bioetanol a partir de caña de azúcar se convirtió desde 2005 en una importante fuente de energía alternativa. Durante su producción se generan de 8 a 13 litros de vinaza por litro, residuo líquido rico en materia orgánica, potasio, calcio, magnesio, azufre y nitrógeno. Su uso como fertilizante es una alternativa que permite su degradación y el reciclaje de sus nutrientes, en sustitución de fertilizantes químicos. Con el objetivo de identificar indicadores para el monitoreo de la aplicación de vinaza al cultivo de caña de azúcar, se evaluaron diferentes parámetros microbianos de suelos en predios de producción de Bella Unión, Artigas, Uruguay. Se estableció una línea de base para estas variables y su relación con variables químicas. Por dos años consecutivos se determinó la abundancia de bacterias heterótrofas, amonificantes, actinobacterias, hongos y levaduras, y la actividad microbiana medida como respiración. Las primeras cuatro poblaciones se correlacionaron entre sí y con el contenido de potasio en el suelo. El seguimiento de la aplicación de vinaza permite establecer un protocolo que optimice su aprovechamiento como fertilizante y minimice su impacto ambienta

Evaluation of the phytotoxic and antifungal activity of C-17-sesquiterpenoids as potential biopesticides

BACKGROUND Natural products are a promising source for the development of new pesticides with alternative mechanisms of action. In this study, we evaluated the phytotoxic and antifungal activity of a novel family of natural C-17-sesquiterpenoids and performed a study of the effect caused by the elimination of the alpha-methylene-gamma-butyrolactone system and its importance to their biological activity. RESULTS Many tested compounds exhibited a strong phytotoxic activity. Lappalone and pertyolide B were the most potent molecules from the tested group. Lappalone displayed a strong inhibition profile against selected weed species, reaching a half-maximal inhibitory concentration (IC50) value of 5.0 mu m against Echinochloa crus-galli L. shoot and 5.7 mu m against the germination rate of Amaranthus viridis L., as well as a good stimulation of the germination of Phelipanche ramosa L. Pertyolide B demonstrated excellent inhibition against Amaranthus viridis L. (IC50: 56.7, 70.3 and 24.0 mu m against the root and shoot growth, and germination rate, respectively) and Allium cepa L. (representative of the Liliaceae family, with IC50 values of 25.3 and 64.4 mu m against root and shoot growth). Regarding the antifungal activity, pertyolide B presented significant activity against Colletotrichum fragareae and Fusarium oxysporum with a minimum inhibitory concentration of 6.6 mu g mu L-1. CONCLUSION The bioassays revealed that frequently the presence of the alpha-methylene-gamma-butyrolactone system is not essential for the bioactivities of sesquiterpene lactones, and suggest that C-17-sesquiterpenoids may function through a different mechanism of action not related to the widely assumed Michael addition

Identification and characterization of a solute carrier, CIA8, involved in inorganic carbon acclimation in Chlamydomonas reinhardtii

© The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. The supply of inorganic carbon (Ci) at the site of fixation by Rubisco is a key parameter for efficient CO2 fixation in aquatic organisms including the green alga, Chlamydomonas reinhardtii. Chlamydomonas reinhardtii cells, when grown on limiting CO2, have a CO2-concentrating mechanism (CCM) that functions to concentrate CO2 at the site of Rubisco. Proteins thought to be involved in inorganic carbon uptake have been identified and localized to the plasma membrane or chloroplast envelope. However, current CCM models suggest that additional molecular components are involved in Ci uptake. In this study, the gene Cia8 was identified in an insertional mutagenesis screen and characterized. The protein encoded by Cia8 belongs to the sodium bile acid symporter subfamily. Transcript levels for this gene were significantly up-regulated when the cells were grown on low CO2. The cia8 mutant exhibited reduced growth and reduced affinity for Ci when grown in limiting CO2 conditions. Prediction programs localize this protein to the chloroplast. Ci uptake and the photosynthetic rate, particularly at high external pH, were reduced in the mutant. The results are consistent with the model that CIA8 is involved in Ci uptake in C. reinhardtii

Identification and characterization of a solute carrier, CIA8,involved in inorganic carbon acclimation in Chlamydomonas reinhardtii

The supply of inorganic carbon (Ci) at the site of fixation by Rubisco is a key parameter for efficient CO2 fixation in aquatic organisms including the green alga, Chlamydomonas reinhardtii. Chlamydomonas reinhardtii cells, when grown on limiting CO2, have a CO2-concentrating mechanism (CCM) that functions to concentrate CO2 at the site of Rubisco. Proteins thought to be involved in inorganic carbon uptake have been identified and localized to the plasma membrane or chloroplast envelope. However, current CCM models suggest that additional molecular components are involved in Ci uptake. In this study, the gene Cia8 was identified in an insertional mutagenesis screen and characterized. The protein encoded by Cia8 belongs to the sodium bile acid symporter subfamily. Transcript levels for this gene were significantly up-regulated when the cells were grown on low CO2. The cia8 mutant exhibited reduced growth and reduced affinity for Ci when grown in limiting CO2 conditions. Prediction programs localize this protein to the chloroplast. Ci uptake and the photosynthetic rate, particularly at high external pH, were reduced in the mutant. The results are consistent with the model that CIA8 is involved in Ci uptake in C. reinhardtii

Agricultural Research Service Weed Science Research: Past, Present, and Future

The U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) has been a leader in weed science research covering topics ranging from the development and use of integrated weed management (IWM) tactics to basic mechanistic studies, including biotic resistance of desirable plant communities and herbicide resistance. ARS weed scientists have worked in agricultural and natural ecosystems, including agronomic and horticultural crops, pastures, forests, wild lands, aquatic habitats, wetlands, and riparian areas. Through strong partnerships with academia, state agencies, private industry, and numerous federal programs, ARS weed scientists have made contributions to discoveries in the newest fields of robotics and genetics, as well as the traditional and fundamental subjects of weed-crop competition and physiology and integration of weed control tactics and practices. Weed science at ARS is often overshadowed by other research topics; thus, few are aware of the long history of ARS weed science and its important contributions. This review is the result of a symposium held at the Weed Science Society of America\u27s 62nd Annual Meeting in 2022 that included 10 separate presentations in a virtual Weed Science Webinar Series. The overarching themes of management tactics (IWM, biological control, and automation), basic mechanisms (competition, invasive plant genetics, and herbicide resistance), and ecosystem impacts (invasive plant spread, climate change, conservation, and restoration) represent core ARS weed science research that is dynamic and efficacious and has been a significant component of the agency\u27s national and international efforts. This review highlights current studies and future directions that exemplify the science and collaborative relationships both within and outside ARS. Given the constraints of weeds and invasive plants on all aspects of food, feed, and fiber systems, there is an acknowledged need to face new challenges, including agriculture and natural resources sustainability, economic resilience and reliability, and societal health and well-being

Major prospects for exploring canine vector borne diseases and novel intervention methods using 'omic technologies

Canine vector-borne diseases (CVBDs) are of major socioeconomic importance worldwide. Although many studies have provided insights into CVBDs, there has been limited exploration of fundamental molecular aspects of most pathogens, their vectors, pathogen-host relationships and disease and drug resistance using advanced, 'omic technologies. The aim of the present article is to take a prospective view of the impact that next-generation, 'omics technologies could have, with an emphasis on describing the principles of transcriptomic/genomic sequencing as well as bioinformatic technologies and their implications in both fundamental and applied areas of CVBD research. Tackling key biological questions employing these technologies will provide a 'systems biology' context and could lead to radically new intervention and management strategies against CVBDs

Pathogen die-off in vermicomposting process

Vermicomposting has been utilised in waste management for a long time, as it is a good alternative to microbial composting. Vermicomposting toilets are an alternative to the common flush toilets to conserve water and reduce environment pollution due to disposal of sludge and wastewater from sewage treatment plants. The factors that are of main concern in using vermicomposted faecal matter in gardens are the health risks associated with the pathogens that are contained in faecal matter. Therefore this study investigated the pathogen die off in the vermicomposting process of human faecal matter. Faeces was collected in a Vermicom composting toilet using sawdust as a covering substrate. A portion of the samples was spiked with a known concentration of Escherichia coli, Enterococcus faecalis and Salmonella typhimurium. The faecal matter was then vermicomposted over a period of nine months. Sampling was undertaken monthly to determine the pathogen concentrations. The pathogen levels declined steadily over the composting period and were sufficiently reduced by the fourth month to the quality of class A or B composts according to the ARMCANZ (1995) guidelines for composts. A slight regrowth occurred in the sixth month. However, at the end of the composting period determined by the physical and chemical quality of compost, the pathogens declined to below detection levels