Chlamydiae possess an intracellular developmental cycle defined by the orderly interconversion of infectious, metabolically inactive elementary bodies and noninfectious, dividing reticulate bodies. Only a few stage-specific genes have been cloned and sequenced, including the late-stage cysteine-rich protein operon and two late-stage genes encoding histone-like proteins. The aims of this study were to identify additional late-stage genes of Chlamydia trachomatis, analyze the upstream DNA sequence of late genes, and determine the sigma factor requirement of late genes. Stage-specific RNA, made by chlamydiae isolated from host cells, was used to probe C. trachomatis genomic libraries. Two new late genes, designated ltuA and ltuB, were identified, cloned, and sequenced. The predicted peptides encoded by ltuA and ltuB do not bear strong homology to known proteins, and the function of the new late genes is not known. The 5 ends of the transcripts of ltuA, ltuB, the cysteine-rich protein operon, and the two histone-like genes (hctA and hctB) were mapped, and a consensus ؊10 promoter region of TATAAT was derived from their upstream DNA sequences. In vitro transcription from templates encoding the promoter regions of ltuA, ltuB, and hctA cloned into the transcription assay vector pUC19-spf was found to be strongly stimulated by the addition of recombinant chlamydial 66 , while transcription from the putative hctB promoter region cloned in pUC19-spf was not detected in either the presence or absence of added 66. These results suggest that the transcription of at least some chlamydial late-stage genes is dependent on 66 , which is homologous to the major sigma factors of other eubacteria.

These data indicate that oral Gln supplementation, through support of host Gln stores and glutathione production, may decrease tumor growth by enhancing NK cell activity.

No abstract

The incorporation of radiolabeled GTP into RNA in host-free Chiamydia trachomatis serovar L2 organisms was investigated. The incorporation was partially inhibited by rifampin and dactinomycin and hydrolyzed by RNase. RNA made by host-free chlamydiae consisted mainly of species of fewer than 800 bases in size, although 16S and 23S species were noted by agarose-gel electrophoresis. The hybridization of radiolabeled host-free RNA to restriction fragments of the gene encoding the major outer membrane protein was analyzed; all regions of the gene were transcribed. The relative intensity of hybridization of host-free RNA made by chlamydiae isolated during the middle and late stages of the developmental cycle to the DNA of clones encoding gene products known to be made at these times in vivo indicated that the temporal patterns of host-free and in vivo transcription were similar. Radiolabeled RNA from 1-and 24-h host-free Chlamydia psittaci 6BC organisms hybridized to many of the same EcoRI and BamHIl restriction fragments of C. psittaci genomic DNA, although some differences could be noted. When these RNAs were used to screen a partial C. psittaci genomic library in Agtll, plaques were identified that reacted mainly either with 1-h RNA or with 24-h RNA. Because RNA synthesized by host-free chlamydiae appears to be developmental cycle stage specific, transcripts made by host-free chlamydiae may be convenient probes that can be used to clone developmental stage-specific chlamydial genes.

Diffuse reflectance spectroscopy to monitor murine colorectal tumor progression and therapeutic response," J. AbstractSignificance: Many studies in colorectal cancer (CRC) use murine ectopic tumor models to determine response to treatment. However, these models do not replicate the tumor microenvironment of CRC. Physiological information of treatment response derived via diffuse reflectance spectroscopy (DRS) from murine primary CRC tumors provide a better understanding for the development of new drugs and dosing strategies in CRC.Aim: Tumor response to chemotherapy in a primary CRC model was quantified via DRS to extract total hemoglobin content (tHb), oxygen saturation (StO 2 ), oxyhemoglobin, and deoxyhemoglobin in tissue.Approach: A multimodal DRS and imaging probe (0.78 mm outside diameter) was designed and validated to acquire diffuse spectra longitudinally-via endoscopic guidance-in developing colon tumors under 5-fluoruracil (5-FU) maximum-tolerated (MTD) and metronomic regimens. A filtering algorithm was developed to compensate for positional uncertainty in DRS measurements Results: A maximum increase in StO 2 was observed in both MTD and metronomic chemotherapy-treated murine primary CRC tumors at week 4 of neoadjuvant chemotherapy, with 21 AE 6% and 17 AE 6% fold changes, respectively. No significant changes were observed in tHb. Conclusion:Our study demonstrates the feasibility of DRS to quantify response to treatment in primary CRC models.