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The COVID-19 pandemic brought about national restrictions on people's movements, in effect commencing a socially engineered transport emission reduction experiment. In New Zealand during the most restrictive alert level (Level 4), roadside concentrations of nitrogen dioxide (NO 2 ) were reduced 48-54% compared to Business-as-usual (BAU) values. NO 2 concentrations rapidly returned to near mean levels as the alert levels decreased and restrictions eased. PM 10 and PM 2.5 responded differently to NO 2 during the different alert levels. This is due to particulates having multiple sources, many of natural origin and therefore less influenced by human activity. PM 10 and PM 2.5 concentrations were reduced during alert level 4 but to a lesser extent than NO 2 and with more variability across regions. Particulate concentrations increased notably during alert level 2 when many airsheds reported concentrations above the BAU means. To provide robust BAU reference concentrations, simple 5-year means were calculated along with predictions from machine learning modelling that, in effect, removed the influence of meteorology on observed concentrations. The results of this study show that latter method was found to be more closely aligned to observed values for NO 2 as well as PM 2.5 and PM 10 away from coastal regions., Competing Interests: No known competing interests., (© 2021 Elsevier Ltd. All rights reserved.)

Nitrogen is one of the most important ecosystem nutrients and often its availability limits net primary production as well as stabilization of soil organic matter. The long-term storage of nitrogen-containing organic matter in soils was classically attributed to chemical complexity of plant and microbial residues that retarded microbial degradation. Recent advances have revised this framework, with the understanding that persistent soil organic matter consists largely of chemically labile, microbially processed organic compounds. Chemical bonding to minerals and physical protection in aggregates are more important to long-term (i.e., centuries to millennia) preservation of these organic compounds that contain the bulk of soil nitrogen rather than molecular complexity, with the exception of nitrogen in pyrogenic organic matter. This review examines for the first time the factors and mechanisms at each stage of movement into long-term storage that influence the sequestration of organic nitrogen in the mineral soil of natural temperate ecosystems. Because the factors which govern persistence are different under this newly accepted paradigm we examine the policy and management implications that are altered, such as critical load considerations, nitrogen saturation and mitigation consequences. Finally, it emphasizes how essential it is for this important but underappreciated pool to be better quantified and incorporated into policy and management decisions, especially given the lack of evidence for many soils having a finite capacity to sequester nitrogen., (Published by Elsevier B.V.)

The synthesis and structure-activity relationship of a novel series of aminopyrimidines are exemplified. Results of key compounds from within this series in the E-selectin reporter cell assay are also reported.

Background: Inflammatory bowel disease (IBD) is characterised by intense mucosal recruitment of activated leukocytes. Chemokines determine inflammatory leukocyte recruitment and retention., Aim: To compare expression of the entire chemokine family within colonic mucosa from IBD patients and uninflamed controls., Methods: A microarray of cDNAs, representing every member of this superfamily and their cognate receptors, was hybridised with probes derived from colonoscopic biopsies., Results: A distinct subset of chemokines, consisting of CXCLs 1-3 and 8 and CCL20, was upregulated in active colonic IBD, compared with uninflamed areas or tissue from controls. Increased expression of their cognate receptors, CXCR1, CXCR2 and CCR6, was confirmed by quantitative PCR and immunohistochemistry. An identical chemokine response was induced in Caco-2 cells by stimulation with interleukin (IL)-1beta, but not tumour necrosis factor-alpha (TNF-alpha). By contrast, IL-1beta and TNF-alpha were synergistic in an HT29 cell line and primary keratinocytes., Conclusions: IL-1beta and TNF-alpha appear to be the pivotal mediators of a previously unidentified coordinated epithelial chemokine response that dominates the mucosal chemokine environment in inflamed IBD tissue.

A novel series of aminopyrimidine IKK2 inhibitors have been developed which show excellent in vitro inhibition of this enzyme and good selectivity over the IKK1 isoform. The relative potency and selectivity of these compounds has been rationalized using QSAR and structure-based modelling.

The Staphylococcus aureus enterotoxin type D was cloned and expressed in Escherichia coli X1776 either as mature toxin or as a fusion with E. coli beta-galactosidase. Regulated expression was obtained and levels of toxin produced were in the order of 10(-3)-fold higher than in S. aureus.

A series of six expression vectors, pXM184Lac.A, B, C, pXM184Z.A, B, C, based on the low copy plasmid pACYC184 that allow for expression of proteins fused to beta-galactosidase in Escherichia coli is described. A level of 50,000 units of beta-galactosidase is routinely observed and is easily identifiable on protein gels. This paper also reports the tight regulation of expression of the Trc promoter in these vectors using the LacIq repressor.

Four strains of Escherichia coli were tested for electroporation-induced plasmid transformation using a high voltage pulse in a square waveform. Conditions for optimal transformation were determined for each strain and transformation frequencies found to be comparable to those reported previously for E. coli with a sinusoidal waveform of exponential decaying pulse.

We describe the isolation and characterisation of twelve different mutations that reduce gene expression from the galP2 promoter, starting with a gal regulatory region with a mutation that inactivated galP1, the cAMP-CRP-dependent promoter. Seven of the new mutations reduce the initiation of transcription at P2 whereas the others reduce translation initiation of the first gal operon gene, galE. Two of the mutations affecting translation fall in the galE initiation codon and the Shine-Dalgarno sequence. Mutations that allow the formation of a stem-loop structure in the messenger including this sequence also reduce translation. A deletion of 11 bp, upstream of the Shine-Dalgarno sequence, almost totally prevents translation. Although none of the point mutations that reduced transcription initiation at P2 fall in the -35 region, we repeatedly isolated insertions in this zone. The point mutations all fell around the -10 region: the strongest effects were found with mutations that altered the sequence away from the consensus that has been established for Escherichia coli promoters. The effects of the two strongest P2 mutations were investigated in the absence of the P1 mutation used for their isolation. One mutation, a T:A to C:G transition at -12, inactivates both P2 and P1. In contrast the other, a T:A to G:C transversion at -19, specifically inactivates P2, but leaves P1 partially active even in the absence of cAMP-CRP. The implications of this are discussed in the context of how cAMP-CRP controls the balance between transcription from P2 and P1 at the gal operon regulatory region.

Twenty-nine antibiotic-resistant isolates of thermophilic bacilli were examined for the presence of covalently closed circular duplex DNA molecules by agarose-gel electrophoresis and caesium chloride-ethidium bromide density gradient centrifugation. Five of the 29 strains tested contained covalently closed circular molecules. Two of the streptomycin-resistant strains contained the same two plasmids: pAB118A of molecular weight 4.9 X 10(6) (7.0 kilobases) and pAB118B of molecular weight 3.0 X 10(6) (4.3 kilobases). Two of the tetracycline-resistant strains each contained a plasmid (pAB124) of molecular weight 2.9 X 10(6) (4.14 kilobases), while a third harboured a small plasmid (pAB128) of molecular weight 2.5 X 10(6) (3.57 kilobases). These plasmids were digested with 19 different restriction endonucleases and the numbers of cleavage sites were determined. Transformation of Bacillus subtilis (168 (Trp-) with purified plasmid DNA indicated that pAB124 conferred tetracycline resistance on the host.

Using gene-manipulation techniques, we made a set of short insertions and deletions in the Escherichia coli galactose operon between the transcription start site and the Shine-Dalgarno sequence of the first gene of the operon, galE. Translation initiation is severely reduced when the distance between the 5' end of the message and the Shine-Dalgarno sequence drops below 15 bases. Transcription of the gal operon can start at two distinct sites, S1 and S2, separated by 5 bp, situated 16 and 21 bp upstream of the galE Shine-Dalgarno sequence, respectively. When transcription starts at S2, gal operon expression is discoordinate as the galE gene is better translated than promoter-distal genes. Here we report that gal operon expression is discoordinate even when message starting at S2 is shortened. This shows that the better translation of galE from transcripts starting at S2 is not simply due to the fact that they are longer than transcripts starting at S1.

The purification and characterization of a new restriction endonuclease, BclI from the extreme thermophile Bacillus caldolyticus is reported. This enzyme recognizes the sequence : formula: (see text) and cleaves at the positions indicated by the arrows.

A restriction endonuclease cleavage map of the tetracycline resistance plasmid pAB124, originally isolated from Bacillus stearothermophilus, was constructed using ten enzymes. Tetracycline resistance was associated with a 1 x 95 megadalton (Md) region of pAB124 lying between two EcoRI sites, and this region was circularized to produce a viable tetracycline resistance plasmid (pAB224), with two EcoRI fragments of pAB124 deleted amounting to 0 x 95 Md. A second plasmid (pAB524) with one EcoRI fragment (0 x 6 Md) of pAB124 deleted was also constructed. Restriction endonuclease cleavage maps of pAB224 and pAB524 were constructed.