Development of a Phage Cocktail to Target Salmonella Strains Associated with Swine

Infections caused by multidrug resistant Salmonella strains are problematic in swine and are entering human food chains. Bacteriophages (phages) could be used to complement or replace antibiotics to reduce infection within swine. Here, we extensively characterised six broad host range lytic Salmonella phages, with the aim of developing a phage cocktail to prevent or treat infection. Intriguingly, the phages tested differed by one to five single nucleotide polymorphisms. However, there were clear phenotypic differences between them, especially in their heat and pH sensitivity. In vitro killing assays were conducted to determine the efficacy of phages alone and when combined, and three cocktails reduced bacterial numbers by ~2 × 103 CFU/mL within two hours. These cocktails were tested in larvae challenge studies, and prophylactic treatment with phage cocktail SPFM10-SPFM14 was the most efficient. Phage treatment improved larvae survival to 90% after 72 h versus 3% in the infected untreated group. In 65% of the phage-treated larvae, Salmonella counts were below the detection limit, whereas it was isolated from 100% of the infected, untreated larvae group. This study demonstrates that phages effectively reduce Salmonella colonisation in larvae, which supports their ability to similarly protect swine.

A PROENVIRONMENTAL VALUE CONSTRUCT TO DEAL WITH PLASTIC POLLUTION

Plastics are man-made synthetic materials. They are made mostly from crude oil even though natural gas and coal could also be used for manufacturing plastics. The multiplicity of its uses together with its versatile properties has made it indispensable to modern living. The average life of plastics differs in various industrial sectors. The generation of waste depends on the mean-product lifetime of the product into which plastics have been integrated. And when this waste is not handled properly (recycled or incinerated under controlled environment), the problem of pollution emerges. Plastics in the form of microplastics have been found in food chains as well, threatening human wellbeing. A model to better understand the source - use and afteruse of plastics is the central focus of this article. It looks at the need for building a sustainable model to deal with plastic pollution.

Epimerization of Deoxynivalenol by the Devosia Strain A6-243 Assisted by Pyrroloquinoline Quinone

Deoxynivalenol (DON) is a secondary metabolite produced by several Fusarium species that is hazardous to humans and animals after entering food chains. In this study, by adding cofactors, the Devosia strain A6-243 is identified as the DON-transforming bacteria from a bacterial consortium with the ability to biotransform DON of Pseudomonas sp. B6-24 and Devosia strain A6-243, and its effect on the biotransformation process of DON is studied. The Devosia strain A6-243 completely biotransformed 100 μg/mL of DON with the assistance of the exogenous addition of PQQ (pyrroloquinoline quinone) within 48 h and produced non-toxic 3-epi-DON (3-epi-deoxynivalenol), while Pseudomonas sp. B6-24 was not able to biotransform DON, but it had the ability to generate PQQ. Moreover, the Devosia strain A6-243 not only degraded DON, but also exhibited the ability to degrade 3-keto-DON (3-keto-deoxynivalenol) with the same product 3-epi-DON, indicating that DON epimerization by the Devosia strain A6-243 is a two-step enzymatic reaction. The most suitable conditions for the biodegradation process of the Devosia strain A6-243 were a temperature of 16–37 °C and pH 7.0–10, with 15–30 μM PQQ. In addition, the Devosia strain A6-243 was found to completely remove DON (6.7 μg/g) from DON-contaminated wheat. The results presented a reference for screening microorganisms with the ability of biotransform DON and laid a foundation for the development of enzymes for the detoxification of mycotoxins in grain and its products.

Economy of the mexican agriculture sector in times of COVID-19

<p>COVID-19, a pandemic disease caused by SARS-CoV-2, changed the production schemes and supply chains in all spheres of the world’s economy. The agricultural sector in Mexico was no exception, although it has been so essential during the pandemic that its growth was higher than the other sectors of the Mexican economy and it stood out as a food supplier in the world in 2020. Farmers’ vocations and the integration of productive food chains led to a surplus of 1.2 billion dollars, with an annual increase of 39.92%. The pandemic is a challenge and an opportunity for the Mexican countryside in terms of digital and technological innovation derived from border investigation. However, it is crucial to establish public agricultural planning policies to help optimize this area of opportunity by focusing on new production and national and international trade models, responding efficiently to national visions to benefit producers-consumers and guaranteeing food security in the framework of the UN’s international policies for sustainable development, the IPCC’s reduction of climate impact and ensuring human health by the WHO.</p>

Microplastic Contamination in Human Stools, Foods, and Drinking Water Associated with Indonesian Coastal Population

Approximately 381 million tons of plastic are produced globally every year, and the majority of it ends up as pollutants. In the environment, plastic waste is fragmented into microplastic particles less than 5 mm in size; owing to their small size, durability, and abundance, they can easily be dispersed, incorporated into the food chains, and enter the human body. The extent of microplastic exposure in the human body has become a major concern in many countries, including in Indonesia, the second largest plastic waste contributor in the world. Here, we report the detection of microplastics in human stools collected from a fisherman community in the coastal area of Surabaya, Indonesia. Microplastics were found in more than 50% of samples analyzed with a concentration ranging from 3.33 to 13.99 µg of microplastic per gram of feces (µg/g). HDPE was observed as the most prevalent type of microplastic, with an average concentration of 9.195 µg/g in positive samples. Different types of microplastics were also detected in seafood, staple foods, drinking water, table salts, and toothpaste, which were regularly used and consumed by the study participants. Results from this preliminary study indicate widespread contamination of microplastic in the human body and in consumables associated with the coastal populations of Indonesia.

Trophic Transfer without Biomagnification of Cadmium in a Soybean-Dodder Parasitic System

Cadmium (Cd) is among the most available and most toxic heavy metals taken up by plants from soil. Compared to the classic plant-animal food chains, the host-parasitic plant food chains have, thus far, been largely overlooked in the studies of Cd trophic transfer. To investigate the pattern of Cd transfer during the infection of parasitic plants on Cd-contaminated hosts, we conducted a controlled experiment that grew soybeans parasitized by Chinese dodders (Cuscuta chinensis) in soil with different levels of Cd treatment, and examined the concentration, accumulation, allocation and transfer coefficients of Cd within this parasitic system. Results showed that among all components, dodders accounted for more than 40% biomass of the whole system but had the lowest Cd concentration and accumulated the least amount of Cd. The transfer coefficient of Cd between soybean stems and dodders was much lower than 1, and was also significantly lower than that between soybean stems and soybean leaves. All these features were continuously strengthened with the increase of Cd treatment levels. The results suggested no evidence of Cd biomagnification in dodders parasitizing Cd-contaminated hosts, and implied that the Cd transfer from hosts to dodders may be a selective process.

Fishing triggers trophic cascade in terms of variation, not abundance in an allometric trophic network model

Trophic cascade studies often rely on linear food chains instead of complex food webs and are typically measured as biomass averages, not as biomass variation. We study trophic cascades propagating across a complex food web including a measure of biomass variation in addition to biomass average. We examined whether different fishing strategies induce trophic cascades and whether the cascades differ from each other. We utilized an allometric trophic network (ATN) model to mechanistically study fishing-induced changes in food-web dynamics. Different fishing strategies did not trigger traditional, reciprocal trophic cascades, as measured in biomass averages. Instead, fishing triggered a variation cascade that propagated across the food web including fish, zooplankton and phytoplankton species. In fisheries that removed a large amount of top-predatory and cannibalistic fish, the biomass oscillations started to decrease after fishing was started. In fisheries that mainly targeted large planktivorous fish, the biomass oscillations did not dampen, but slightly increased over time. Removing species with specific ecological functions might alter the food web dynamics and potentially affect the ecological resilience of aquatic ecosystems.