Shigellae, the causative agents of bacillary dysentery, are capable of adhering to and invading epithelial cells and spreading into adjacent cells. A chromosomal mutant of ShigeUla flexneri 2a YSH6000 with reduced invasive capacity was isolated by TnS insertion mutagenesis. The linkage of the mutant phenotype to the TnS insertion was determined by P1 phage transduction. The site of the TnS insertion was assigned to a NotI chromosomal restriction map, confirming that the virulence-associated locus, designated vacB, is a new locus on the chromosome. In the vacB mutant, production of the four plasmid-encoded virulence antigens, IpaB, -C, and -D and VirG, decreased to a low level compared with that in the wild type. In contrast, levels of transcription of the operons for virG, ipa, region-3.4, region-5, virF, and virB on the large plasmid, as determined by Northern dot blotting, were unaffected in the vacB mutant. Furthermore, transcriptional activation of the ipa operon by exploiting a tac promoter could not restore the vacB mutant to production of the same levels of the IpaB, -C, and -D proteins as those in the wild type, indicating that the vacB locus is involved in expression of the vir genes on the large plasmid at the posttranscriptional level. Cloning followed by nucleotide sequencing of the vacB region showed it to contain a 2, Shigellae cause bacillary dysentery in humans and monkeys. The essential early steps in infection comprise bacterial adherence and invasion of colonic epithelial cells followed by intracellular bacterial multiplication and spread of invading bacteria to adjacent cells (10). Seven separate virulence-associated DNA segments have been identified on the large 230-kb plasmid of Shigella flexneri 2a. In a 31-kb DNA sequence, five contiguous segments, designated virB, ipaBCD (ipa), and region-3, -4, and -5, were characterized. The virB gene acts as a positive regulator for the expression of the other four virulence regions (1); the ipa operon encodes three invasion-associated antigens, IpaB, -C, and -D; and region-3, -4, and -5 are required for both adherence to epithelial cells and excretion of the Ipa proteins (20a). The virG gene, outside the cluster, encodes a 116-kDa immunogenic, surface-exposed outer membrane protein and is es-

An oxalate-degrading Enterococcus faecalis was isolated from human stools under anaerobic conditions. The bacteria required a poor nutritional environment and repeated subculturing to maintain their oxalate-degrading ability. The E. faecalis produced 3 proteins (65, 48, and 40 kDa) that were not produced by non-oxalate-degrading E. faecalis as examined by SDS-PAGE. Antibodies against oxalyl-coenzyme A decarboxylase (65 kDa) and formyl-coenzyme A transferase (48 kDa) obtained from Oxalobacter formigenes (an oxalate-degrading anaerobic bacterium in the human intestine) reacted with 2 of the proteins (65 and 48 kDa) from the E. faecalis as examined by Western blottings. This is the first report on the isolation of oxalate-degrading facultative anaerobic bacteria from humans.

Aeromonas hydrophila Ae6 had 2 morphologically distinctive kinds of pili. One appeared rigid and straight with a diameter of 9 nm (R-pili). The other appeared wavy and flexible with a diameter of 7 nm (W-pili). W-pili w-ere very few on the cell as compared with R-pili. In this study, W-pili were purified and characterized. The pili consisted of a subunit protein with a molecular weight of 21 kDa as estimated by SDS-PAGE. There was no immunological cross-reaction between W-pili and other cellular components. The strain Ae6 and its purified Wpili adhered to human and rabbit intestine and agglutinated human and rabbit erythrocytes. Organisms pretreated with the Fab fraction of anti-pilus antibody failed to adhere to the intestine. Pretreatment of intestine with purified W-pili blocked adherence of the organisms to the intestine. These results suggest that the W-pili are the colonization factor of A. hydrophila Ae6.

Aeromonas hydrophila (Ae6) has 2 morphologically distinctive kinds of pili. One appeared rigid, channeled, and straight with a diameter of 9 nm (Ae6-R pili). The other looked flexible, wavy, and having helical structure with a diameter of 7 nm (Ae6-W pili). Ae6-R pili were purified and characterized.The pili consisted of a subunit protein with a molecular weight of 18 kDa as estimated by SDS-PAGE, and contained 42.3% hydrophobic amino acids and one cysteine residue.The pilus was solubilized to 18 kDa subunit protein by 2-mercaptoethanol.dithiothreitol, hydrochloric acid, or heating at 120 C for 5 min. The organism Ae6 was strongly adhesive to rabbit intestines as well as human intestines, and agglutinated erythrocytes. Anti-pili antibody (Fab fraction) did not block the adhesion. Purified Ae6-R pili did not adhere to the intestine or to the erythrocytes.However, the anti-pili Fab inhibited pellicle formation of the organisms cultured in broth, and also inhibited salt agglutination with ammonium sulfate.From these results, Ae6-R pili are not likely a colonization factor but probably play a role in the autoaggregation of the organisms.

Background: Numerous reports regarding sarcopenia have focused on the quantity of skeletal muscle. In contrast, the impact of the quality of skeletal muscle has not been well investigated. Methods: A retrospective analysis of 115 patients who underwent initial hepatectomy for colorectal liver metastasis between January 2009 and December 2016 in our hospital was performed. Intramuscular adipose tissue content (IMAC) was used to evaluate the quality of skeletal muscle by analysing computed tomography (CT) images at the level of the umbilicus. The impact of poor skeletal muscle quality on short-term and long-term outcomes after hepatectomy for colorectal liver metastasis was analysed. Results: Patients were divided into two groups (high IMAC and normal IMAC) according to their IMAC values, and their backgrounds were compared. There were no significant differences in most factors between the two groups. However, both body mass index (P = 0.030) and the incidence of postoperative complications of Clavien-Dindo grade 3 or worse (P = 0.008) were significantly higher in the high-IMAC group. In multivariate analyses, an operative blood loss > 600 ml (P = 0.006) and high IMAC (P = 0.008) were associated with postoperative complications of Clavien-Dindo grade 3 or worse. Overall survival and recurrence-free survival were significantly lower (P < 0.001 and P = 0.045, respectively) in the high-IMAC group than in the normal IMAC group. In multivariate analyses for poor overall survival, high IMAC was associated with poor overall survival (P < 0.001). Conclusions: IMAC is a prognostic factor for poor short-and long-term outcomes in patients with colorectal liver metastasis.