We report novel findings of significant amounts of 60- and 10-kDa proteins on SDS-PAGE in a culture supernatant of the Clostridium botulinum type D strain 4947 (D-4947). The N-terminal amino acid sequences of the purified proteins were closely related to those of other bacterial GroEL and GroES proteins, and both positively cross-reacted with Escherichia coli GroEL and GroES antibodies. Native GroEL homologue as an oligomeric complex is a weak ATPase whose activity is inhibited by the presence of GroES homologue. The 2634-bp groESL operon of D-4947 was isolated by PCR and sequenced. The sequence included two complete open reading frames (282 and 1629 bp), which were homologous to the groES and groEL gene family of bacterial proteins. Southern and Northern blot analyses indicate that the groESL operon is encoded on the genomic DNA of D-4947 as a single copy, and not on that of its specific toxin-converting phage.
SummaryNet protein utilization (NPU) was examined in pregnant rats fed various levels (1, 3, 6, 10 and 20%) of whole egg protein (WEP), based on their obligatory nitrogen losses. On increase in dietary protein, nitrogen balance improved curvilinearly and the NPU decreased ex ponentially in both pregnant and nonpregnant rats. The utilization efficiency was high in rats fed marginally low protein diets, mainly due to lower urinary nitrogen levels than the obligatory levels of nitrogen loss. The NPUs in pregnant rats fed 1, 3, 6, 10 and 20% WEP diets were 103, 99, 78, 66 and 46, respectively. These values were 15 to 20% higher than those in nonpregnant rats because in pregnant rats obligatory urinary nitrogen loss was higher and the animals took more energy. The problems in application of the NPUs in pregnant rats for estimating the protein allowance of pregnant humans are discussed.
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