Disclosed are gene engineering bacteria for producing L-arginine and a construction method and an application of the gene engineering bacteria. According to the method, genes encoding a carbamoyl phosphate synthetase and a gene encoding an L-arginine biosynthesis pathway enzyme are integrated into Escherichia coli; the present invention has analyzed and reconstructed the arginine synthetic pathway and the metabolic flow related to arginine in the entire amino acid metabolic network in E. coli and finally obtained a genetically engineered bacterial strain which has a clear genetic background, carries no plasmids, undergoes no mutagenesis and is capable of stably and efficiently producing L-arginine.

Provided are nucleic acid constructs, Toxoplasma comprising same, pharmaceutical compositions comprising same and methods using same for delivering a protein-of-interest to a tissue-of-interest of a subject, such as the CNS and further treating a pathology which is treatable by administration of a therapeutic polypeptide in a central nervous system of the subject.

Provided are nucleic acid constructs, Toxoplasma comprising same, pharmaceutical compositions comprising same and methods using same for delivering a protein-of-interest to a tissue-of-interest of a subject, such as the CNS and further treating a pathology which is treatable by administration of a therapeutic polypeptide in a central nervous system of the subject.

Provided are nucleic acid constructs, Toxoplasma comprising same, pharmaceutical compositions comprising same and methods using same for delivering a protein-of-interest to a tissue-of-interest of a subject, such as the CNS and further treating a pathology which is treatable by administration of a therapeutic polypeptide in a central nervous system of the subject.

Provided are nucleic acid constructs, Toxoplasma comprising same, pharmaceutical compositions comprising same and methods using same for delivering a protein-of-interest to a tissue-of-interest of a subject, such as the CNS and further treating a pathology which is treatable by administration of a therapeutic polypeptide in a central nervous system of the subject.

Provided are nucleic acid constructs, Toxoplasma comprising same, pharmaceutical compositions comprising same and methods using same for delivering a protein-of-interest to a tissue-of-interest of a subject, such as the CNS and further treating a pathology which is treatable by administration of a therapeutic polypeptide in a central nervous system of the subject.

Provided herein are cell-free systems for generating carbapenems, e.g., a compound of the Formula (I):

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or salts thereof; wherein , R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are defined herein. Also provided are pharmaceutical compositions comprising a compound generated by the inventive cell-free system, and use of these compounds and compositions for the treatment of bacterial infections.

Provided are a carbamoyl phosphate synthetase large subunit variant, a polynucleotide encoding the variant, a microorganism comprising the variant or polynucleotide, and a method of producing L-ornithine using the same.