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The cyanobacterium Synechococcus elongatus PCC 7942 holds significant potential as a biofactory for recombinant protein (RP) production due to its capacity to harness light energy and utilize CO2. This study aimed to enhance RP production by integration of native promoters and magnetic field application (MF) in S. elongatus PCC 7942. The psbA2 promoter, which responds to stress conditions, was chosen for the integration of the ZsGreen1 gene. Results indicated successful gene integration, affirming prior studies that showed no growth alterations in transgenic strains. Interestingly, exposure to 30 mT (MF30) demonstrated a increase in ZsGreen1 transcription under the psbA2 promoter, revealing the influence of MF on cyanobacterial photosynthetic machinery. This enhancement is likely attributed to stress-induced shifts in gene expression and enzyme activity. MF30 positively impacted photosystem II (PSII) without disrupting the electron transport chain, aligning with the "quantum–mechanical mechanism" theory. Notably, fluorescence levels and gene expression with application of 30 mT were significantly different from control conditions. This study showcases the efficacy of utilizing native promoters and MF for enhancing RP production in S. elongatus PCC 7942. Native promoters eliminate the need for costly exogenous inducers and potential cell stress. Moreover, the study expands the scope of optimizing RP production in photoautotrophic microorganisms, providing valuable insights for biotechnological applications. [ABSTRACT FROM AUTHOR]

Phosphorus is an essential mineral present in the vegetable matter in the form of phytate, which is considered an antinutritional factor. Phytate can be degraded by phytases, which have been used in commercial feeds. However, these enzymes undergo costly isolation and purification processes. In the present study, a genetically modified (GM) Bacillus subtilis strain that expresses a fungal phytase was used as a feed additive. The GM probiotic was added to the commercial feed of shrimp Litopenaeus vannamei and its effects on zootechnical performance, proximate composition of muscle, lipid concentration in hepatopancreas, and expression of genes related to digestion, amino acid metabolism, and antioxidant defenses were analyzed. Although the genetically modified probiotic had no impact on growth parameters, there was a 39% increase in phosphorus content in muscle. In addition, genes related to digestion were downregulated in shrimp hepatopancreas, as well as an increase in lipids in this tissue. These results demonstrate that the GM probiotic increased the efficiency of the use of plant-derived phosphorus, which may imply a decrease in the addition of this element in the diets, as well as minimizing the impact of shrimp farms on the eutrophication of adjacent ecosystems. [ABSTRACT FROM AUTHOR]

Cyanobacteria are a rich source of nutrients in addition to producing bioactive compounds capable of stimulating the immune system of hosts. Also, they can be manipulated with relative ease to produce heterologous proteins. In the present study, a strain of Synechococcus elongatus (PCC7942) was manipulated to produce a prokaryotic β-glucosidase. This strain was added to the diet of Pacific white shrimp Litopenaeus vannamei for 45 days and parameters such as growth performance, proximate composition of muscle tissue and expression of genes related to digestion, amino acid metabolism, immune system and antioxidant defenses were evaluated. Histology of shrimp hepatopancreas was also performed. Transgenic cyanobacteria did not produce negative effects on shrimp growth performance. Regarding proximate composition, an increase in lipid and phosphorus deposition was observed in the muscle of shrimp, as well as lipid in hepatopancreas. Furthermore, an increase in expression of genes related to the immune system (tgase) as well as carbohydrate metabolism and amino acid metabolism (gdh) was observed. It was observed also that both strains of cyanobacteria (wild and transgenic) produced effects on carbohydrate metabolism (increased amy expression) and digestive system (decreased cathB expression). It is possible that cyanobacteria in the diet may be serving as a source of carbohydrates, reducing the use of proteins as a source of energy. It can be concluded that transgenic cyanobacteria had a beneficial effect on shrimp by increasing lipid deposition in muscle and hepatopancreas as well as phosphorus absorption from feed, which can minimize the environmental impact of shrimp farms. [ABSTRACT FROM AUTHOR]

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Copyright of Brazilian Journal of Agricultural Sciences / Revista Brasileira de Ciências Agrárias is the property of Universidade Federal Rural de Pernambuco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)