Early in infection of Bacillus subtilis by bacteriophage SPO1, the synthesis of most host-specific macromolecules is replaced by the corresponding phage-specific biosyntheses. It is believed that this subversion of the host biosynthetic machinery is accomplished primarily by a cluster of early genes in the SPO1 terminal redundancy. Here we analyze the nucleotide sequence of this 11.5-kb "host-takeover module," which appears to be designed for particularly efficient expression. Promoters, ribosome-binding sites, and codon usage statistics all show characteristics known to be associated with efficient function in B. subtilis. The promoters and ribosome-binding sites have additional conserved features which are not characteristic of their host counterparts and which may be important for competition with host genes for the cellular biosynthetic machinery. The module includes 24 genes, tightly packed into 12 operons driven by the previously identified early promoters PE1 to PE12. The genes are smaller than average, with half of them having fewer than 100 codons. Most of their inferred products show little similarity to known proteins, although zinc finger, trans-membrane, and RNA polymerase-binding domains were identified. Transcription-termination and RNase III cleavage sites were found at appropriate locations.
The objectives of this effort were to identify basic descriptors of the east Mississippi (MS) catfish industry, identify prevalent diseases affecting this region, and determine the direct economic impacts of these diseases representing the 2016 production season. Data from east MS catfish operations were collected over a 3‐month period during the late spring through early summer of 2017. A 95% confidence interval (CI) with finite correction was used to make inferences on the population. The number of operations (115) and number of hectares used for catfish production (4,900 ha) were identified by personal communications and confirmed by satellite imagery. Producers were surveyed a second time by e‐mail (29.6% response) to identify basic industry descriptors, the most predominant catfish diseases of east MS, and their respective direct economic impact. The top‐three diseases, as reported by producers, were virulent Aeromonas hydrophila, the “other” disease category, and Flavobacterium columnare. Producers were surveyed a third time by e‐mail (34% response) to identify the mean (±95% CI) of regional catfish production (8,070 ± 783 kg/ha). Foregone sales loss attributed to catfish disease was reported as the sum of fish loss ($10 million) and production loss ($4.3 million). Foregone income loss resulted from the increased expenditures associated with catfish disease and included medicated feed ($1.9 million), chemical applications ($0.6 million), and miscellaneous ($0.1 million). The total direct economic impact of catfish diseases for the 2016 east MS production season was reported as the sum of foregone sales and foregone income and totaled $16.9 million.
The US catfish industry has undergone significant technological advancements in an attempt to achieve cost efficiencies. This study monitored the progress of the adoption of alternative and complementary technologies in the US catfish industry. A 2019-2020 multi-state in-person survey in Alabama, Arkansas, and Mississippi (n = 68), revealed increased adoption of intensively aerated ponds (6,315 ha) and split ponds (1,176 ha). The adoption of alternative, more intensive, production practices has been accompanied by increased adoption of complementary technologies of fixed-paddlewheel aeration, automated oxygen monitors, and hybrid catfish. As a result, the average aeration rate in the tristate region has increased to 7.8 kW/ha with 97% of catfish farms adopting automated oxygen monitors. About 53% of the water surface area in the tristate region was used for hybrid catfish production. Fingerling producers have also adopted a feed-based, oral vaccine against Enteric Septicemia of Catfish, with 83% of the fingerling farms and 73% of the fingerling production area vaccinated against ESC in 2020. Increased adoption of productivity-enhancing technologies in the US catfish industry explains the 59% increase in foodfish productivity from 2010 to 2019.
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