Publications by authors named "Shilton A"

Cells from all kingdoms of life can enter growth arrest in unfavorable environmental conditions. Key to this process are mechanisms enabling recovery from this state. Staphylococcal type III-A CRISPR-Cas loci encode the Cas10 complex that uses a guide RNA to locate complementary viral transcripts and start an immune response.

View Article and Find Full Text PDF

A hallmark of CRISPR immunity is the acquisition of short viral DNA sequences, known as spacers, that are transcribed into guide RNAs to recognize complementary sequences. The staphylococcal type III-A CRISPR-Cas system uses guide RNAs to locate viral transcripts and start a response that displays two mechanisms of immunity. When immunity is triggered by an early-expressed phage RNA, degradation of viral ssDNA can cure the host from infection.

View Article and Find Full Text PDF

Algal-based waste stabilisation ponds (WSP) are a common wastewater treatment system for small communities but have poor phosphorus removal. Under certain conditions algae in WSPs will perform 'luxury uptake' increasing their phosphorus content to over 3% (gP/gSS) by storing polyphosphate. For the first time in the literature this paper presents a systematic study which determines the conditions needed to maximise phosphorus accumulation within WSP biomass taking into account the interactions between key variables.

View Article and Find Full Text PDF

This study investigates the reduction of aflatoxin M1 (AFM1) in skim milk by using ultraviolet light at 254 nm and the effects of influencing factors on the efficacy including treatment time (min), depth of samples (mm), contamination level (μg L), stirring, temperature, and fat content in milk. The colour and pH of milk samples were measured to evaluate the influence of the treatment on these values. It was found that short-wave ultraviolet radiation (UVC) reduced up to 50% of AFM1 in milk after 20 min of treatment regardless of the initial AFM1 contamination level.

View Article and Find Full Text PDF

The human zinc finger antiviral protein (ZAP) recognizes RNA by binding to CpG dinucleotides. Mammalian transcriptomes are CpG-poor, and ZAP may have evolved to exploit this feature to specifically target non-self viral RNA. Phylogenetic analyses reveal that ZAP and its paralogue PARP12 share an ancestral gene that arose prior to extensive eukaryote divergence, and the ZAP lineage diverged from the PARP12 lineage in tetrapods.

View Article and Find Full Text PDF

Athukoralage et al. (2020) identify a new anti-CRISPR (Acr) that degrades cA, a cyclic oligo-adenylate second messenger produced during the type III CRISPR immune response. This provides an effective way by which invaders can bypass downstream CRISPR effectors that rely on this signaling molecule.

View Article and Find Full Text PDF

Microalgae commonly found in waste stabilization ponds (WSPs) are able to accumulate elevated phosphorus levels within their cells in a process known as luxury uptake. However, there are few studies focused on luxury uptake in full scale WSPs. In order to comprehensively quantify the occurrence of this phenomenon, eight different WSP sites comprising seven primary facultative, six maturation and two high rate algal ponds (HRAPs) spread over several climatic regions were monitored over four seasons.

View Article and Find Full Text PDF

Manure is often added to stabilise anaerobic digesters especially when co-digesting high-energy substrates such as whey. While different researchers have attributed its beneficial effect to various components including alkalinity, nutrients or trace elements this research instead aimed to determine whether microorganisms, such as lactic acid bacteria which are naturally present in the feedstocks, were having a notable beneficial effect on biogas production. Casein whey and cow manure were co-digested with primary sludge and produced 151.

View Article and Find Full Text PDF

Waste stabilization ponds (WSP) are one of the most common forms of wastewater treatment for smaller communities globally, but have poor phosphorus removal. It is known that WSP algae can accumulate polyphosphate within their cells in excess of that needed for cell function. If polyphosphate accumulation could be triggered at the higher range of WSP cell concentrations, phosphorus removal from domestic wastewater could be significantly improved.

View Article and Find Full Text PDF

The Maastricht Acute Stress Test (MAST) is designed to be a simple, quick, and non-invasive procedure aimed at activating the human stress system. The MAST has been developed by combining elements from two of the most common experimental paradigms measuring stress, the Trier Social Stress Test and the Cold Pressor Test. The aim of this study was to use the MAST procedure to elicit strong autonomic and subjective stress responses that can be quantified in terms of (systolic and diastolic) blood pressure, pulse rate (PR), and state anxiety ratings.

View Article and Find Full Text PDF

Over the last decades, several studies have reported emissions of nitrous oxide (N O) from microalgal cultures and aquatic ecosystems characterized by a high level of algal activity (e.g. eutrophic lakes).

View Article and Find Full Text PDF

The degradation of the antibiotic tetracycline, supplied at 100µgL in domestic wastewater, was studied in an outdoor, pilot scale, high rate algal pond (HRAP). Effective operation was demonstrated with the biomass concentration and the chemical oxygen demand removal efficiency averaging 1.2±0.

View Article and Find Full Text PDF

Background: As more and more researchers are turning to big data for new opportunities of biomedical discoveries, machine learning models, as the backbone of big data analysis, are mentioned more often in biomedical journals. However, owing to the inherent complexity of machine learning methods, they are prone to misuse. Because of the flexibility in specifying machine learning models, the results are often insufficiently reported in research articles, hindering reliable assessment of model validity and consistent interpretation of model outputs.

View Article and Find Full Text PDF

TAR DNA-binding protein 43 (TDP-43) is genetically and functionally linked to amyotrophic lateral sclerosis (ALS) and regulates transcription, splicing, and transport of thousands of RNA targets that function in diverse cellular pathways. In ALS, pathologically altered TDP-43 is believed to lead to disease by toxic gain-of-function effects on RNA metabolism, as well as by sequestering endogenous TDP-43 and causing its loss of function. However, it is unclear which of the numerous cellular processes disrupted downstream of TDP-43 dysfunction lead to neurodegeneration.

View Article and Find Full Text PDF

Whereas the fate of emerging contaminants (ECs) during 'conventional' and 'advanced' wastewater treatment (WWT) has been intensively studied, little research has been conducted on the algal WWT ponds commonly used in provincial areas. The long retention times and large surface areas exposed to light potentially allow more opportunities for EC removal to occur, but experimental evidence is lacking to enable definite predictions about EC fate across different algal WWT systems. This study reviews the mechanisms of EC hydrolysis, sorption, biodegradation, and photodegradation, applying available knowledge to the case of algal WWT.

View Article and Find Full Text PDF

The ability to dynamically control algal raceway ponds to maximize biomass productivity and reduce environmental impacts (e.g., land and water use) with consideration of local constraints (e.

View Article and Find Full Text PDF

Recycling a portion of gravity harvested algae (i.e. algae and associated bacteria biomass) has been shown to improve both algal biomass productivity and harvest efficiency by maintaining the dominance of a rapidly-settleable colonial alga, Pediastrum boryanum in both pilot-scale wastewater treatment High Rate Algal Ponds (HRAP) and outdoor mesocosms.

View Article and Find Full Text PDF

A new biomass productivity model was parameterized for Chlorella vulgaris using short-term (<30 min) oxygen productivities from algal microcosms exposed to 6 light intensities (20-420 W/m(2)) and 6 temperatures (5-42 °C). The model was then validated against experimental biomass productivities recorded in bench-scale photobioreactors operated under 4 light intensities (30.6-74.

View Article and Find Full Text PDF

While modeling algal productivity outdoors is crucial to assess the economic and environmental performance of full-scale cultivation, most of the models hitherto developed for this purpose have not been validated under fully relevant conditions, especially with regard to temperature variations. The objective of this study was to independently validate a model of algal biomass productivity accounting for both light and temperature and constructed using parameters experimentally derived using short-term indoor experiments. To do this, the accuracy of a model developed for Chlorella vulgaris was assessed against data collected from photobioreactors operated outdoor (New Zealand) over different seasons, years, and operating conditions (temperature-control/no temperature-control, batch, and fed-batch regimes).

View Article and Find Full Text PDF

The colonial alga Pediastrum boryanum has beneficial characteristics for wastewater treatment High Rate Algal Ponds (HRAP) including high biomass productivity and settleability. Our previous work has shown that these characteristics are enhanced when a portion of gravity harvested algae is recycled back to the pond. To help understand the mechanisms behind the improved performance of P.

View Article and Find Full Text PDF

Biogas production from municipal anaerobic digesters could potentially be boosted via co-digestion with organic wastes such as whey. The challenge is that whey production is seasonal. This research examined the effect of storing whey at ambient temperature on: (1) whey composition; (2) biogas production from co-digestion of the stored whey with municipal primary sludge.

View Article and Find Full Text PDF

Increasing biogas production from municipal anaerobic digesters via additional loading with industrial/agricultural wastes offers a low-cost, sustainable energy generation option of significant untapped potential. In this work, bench-top reactors were used to mimic a full-scale primary sludge digester operating at an organic loading rate (OLR) of 2.4 kg COD/m3 d and a 20 d hydraulic retention time (HRT).

View Article and Find Full Text PDF

The ability to model algal productivity under transient conditions of light intensity and temperature is critical for assessing the profitability and sustainability of full-scale algae cultivation outdoors. However, a review of over 40 modeling approaches reveals that most of the models hitherto described in the literature have not been validated under conditions relevant to outdoor cultivation. With respect to light intensity, we therefore categorized and assessed these models based on their theoretical ability to account for the light gradients and short light cycles experienced in well-mixed dense outdoor cultures.

View Article and Find Full Text PDF

It has previously been shown that recycling gravity harvested algae promotes Pediastrum boryanum dominance and improves harvestability and biomass production in pilot-scale High Rate Algal Ponds (HRAPs) treating domestic wastewater. In order to confirm the reproducibility of these findings and investigate the mechanisms responsible, this study utilized twelve 20 L outdoor HRAP mesocosms operated with and without algal recycling. It then compared the recycling of separated solid and liquid components of the harvested biomass against un-separated biomass.

View Article and Find Full Text PDF