p300 is a nuclear phosphoprotein likely to be involved in the control of cell growth. Here we show that SV40 large T antigen (Tag) forms a specific complex with p300. In various Tag‐expressing cell lines, the affinity of Tag for p300 was restricted to a newly identified unphosphorylated but ubiquitinated form of the protein. Further, Tag did not associate with p300 in an SV40 Tag‐producing cell line (REV2) in which the original transformed phenotype (SV52) is reverted. Biochemical studies demonstrate that both the phosphorylation and the ubiquitination profile of p300 are altered in REV2 with respect to the wild‐type fully transformed SV52 parental cells, wherein Tag‐p300 complexes are readily detected. In contrast to Tag, the adenovirus early expression product E1a interacts with both phosphorylated and unphosphorylated forms of p300. In addition, when REV2 cells were infected with adenovirus, E1a‐p300 complexes were detected, suggesting that the p300 expressed in REV2 has lost the affinity for Tag, but not for E1a. We then compared the ability of Tag and E1a to affect the transcription levels of the cAMP‐responsive promoter (CRE), which is modulated in vivo by p300, in REV2 cells. We found that Tag repressed the CRE promoter in all of the cell lines in which Tag‐p300 complexes were detected, but not in REV2 cells. In contrast, E1a efficiently inhibited CRE‐directed transcription in this cell line. The data thus indicate that the different specificities exhibited by Tag and E1a towards the various forms of p300 are reflected in vivo as a difference in the ability of these viral oncoproteins to modulate the expression of CRE‐containing genes.

The occurrence of Arcobacter spp. was studied in seawater and plankton samples collected from the Straits of Messina, Italy, during an annual period of observation by using cultural and molecular techniques. A PCR assay with three pairs of primers targeting the 16S and 23S rRNA genes was used for detection and identification of Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii in cultures and environmental samples. Only one of the Arcobacter species, A. butzleri, was isolated from seawater and plankton samples. With some samples the A. butzleri PCR assay gave amplified products when cultures were negative. A. cryaerophilus and A. skirrowii were never detected by culture on selective agar plates; they were detected only by PCR performed directly with environmental samples. Collectively, our data suggest that culturable and nonculturable forms of Arcobacter are present in marine environments. The assay was useful for detecting Arcobacter spp. both as free forms and intimately associated with plankton. This is the first report showing both direct isolation of A. butzleri and the presence of nonculturable Arcobacter spp. in the coastal environment of the Mediterranean Sea.

Aims: To determine the abundance of faecal and nonfaecal bacteria related to human and animal health, as free living or associated with small (>64 lm) and large (>200 lm) plankton, samples were collected monthly from the coastal zone at Messina (Italy). Methods and Results: Different enrichment and selective cultural methods were used to determine the abundance of bacteria in sea water and plankton. The bacteria were more frequently isolated from water and large plankton than from small plankton. Vibrio and Aeromonas spp. showed different distribution patterns in water and plankton. Faecal indicators were always present in water and the large size class plankton samples. Enterococci associated with large plankton were more abundant than E. coli in the winter. Vibrio species distributions were different in water and plankton samples. Among arcobacters only A. butzleri was isolated from water and plankton samples. Campylobacter spp. was always absent in small plankton and more frequent in large plankton than in water. Conclusions: The colonization of zooplankton by potentially pathogenic bacteria is a widespread phenomenon. Significance and Impact of the Study: The presence of potentially pathogenic bacteria in sea water and associated with plankton can have ecological and epidemiological implications.

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Aims:  To evaluate the presence of Arcobacter spp. in different biological samples from domestic cats in Southern Italy by using a species‐specific PCR assay and thus to elucidate their potential significance as sources of human infection. Methods and Results:  We investigated the prevalence of Arcobacter DNA in oral swabs, in peripheral blood samples and fine needle lymph node aspirate specimens from 85 cats of which 17 were clinically healthy and 68 had clinical signs of oral disease or lymphadenomegaly. Overall, molecular analysis has shown that Arcobacter‐specific DNA was found in 78·8% (67 of 85) of all the cats. In the 67 Arcobacter‐positive cats, 66 (77·6%) and 29 (34·1%) were found positive for Arcobacter butzleri and Arcobacter cryaerophilus, respectively. None of the examined samples gave a PCR product for Arcobacter skirrowii. Conclusions:  This study demonstrates that pet cats commonly carry Arcobacter in the oral cavity. According to the clinical data, the Arcobacter detection results showed no significant difference between cats with oral pathology and those suffering from other different pathologies. Significance and Impact of the Study:  Pet cats harbour Arcobacter spp. and may play a role in their dissemination in the domestic habitat. The high prevalence in a limited number of cat samples in this study may be of significance.

Two strains of Arcobacter butzleri, ATCC 49616 and an environmental isolate, became nonculturable in seawater microcosms at 4°C by 20 days and at room temperature by 14 days. Nonculturable cells were viable for up to 270 days of incubation in microcosms. Resuscitation of A. butzleri cells from microcosms at both temperatures was achieved 9 days after nutrient addition.The genus Arcobacter is composed of pathogenic species (A. butzleri, A. cryaerophilus, A. skirrowii, and A. cibarius), nonpathogenic species (A. nitrofigilis and A. halophilus), and a number of species not yet established (such as "Candidatus Arcobacter sulfidicus") (4,6,10,20). The nonpathogenic species have been isolated from a variety of habitats, but no association with humans or animals has been reported yet. The other species, A. butzleri, A. cryaerophilus, A. skirrowii, and A. cibarius, are found as inhabitants of several animals, which can serve as natural reservoirs, and are also isolated from various environmental sources, including wastewater, surface water, seawater, and groundwater (5,6,9,11,16,18). Arcobacter infections in humans were also described previously (14). A. butzleri and A. cryaerophilus have been isolated mainly from stool specimens from patients with diarrhea (8,17,21). The significance and prevalence of Arcobacter in human infections have probably been underestimated because of inappropriate detection and cultural methods for stool specimens (17).Environmental studies have revealed differences in the arcobacter detection capabilities of PCR and culture methods with samples taken from marine environments (5). The viable but nonculturable (VBNC) state is a strategy developed by many gram-negative bacteria to survive under adverse environmental conditions (12). According to many studies, pathogenic bacteria in the VBNC state retain their virulence (1, 2, 7, 15). Knowledge of the survival strategies of arcobacters in the environment is very important for both control of water quality and understanding transmission of disease. So far, no reports have been published on the VBNC state of Arcobacter spp. in seawater.The aim of the present study was to investigate the VBNC state of A. butzleri experimentally induced under starvation conditions, using a seawater microcosm at room temperature and at 4°C. Plate counts were compared with total direct counts (Live/Dead) to determine whether nonculturable cells of A. butzleri retain viability. Also, resuscitation experiments were conducted to establish the growth-limiting natural conditions of this species. Furthermore, a fluorescent in situ hybridization (FISH) approach for evaluating the viability of VBNC Arcobacter cells in seawater microcosms was also investigated and discussed.The A. butzleri strains used in this study were ATCC 49616 and Ap-6, a strain isolated from coastal waters of the Strait of Messina (Italy).Flasks containing autoclaved and filter-sterilized seawater were inoculated with each A. butzleri cell suspension to obtain a final concentration of 10 7 CFU ml Ϫ1 . A...

Septic shock is a major cause of mortality in neonates. The hypothesis was tested that neonatal age is associated with altered sensitivity to shock-inducing bacterial products or proinflammatory cytokines (or both). Mice of different ages were inoculated with various doses of lipopolysaccharide (LPS), superantigenic staphylococcal enterotoxin B (SEB), or recombinant tumor necrosis factor-alpha (rTNF-alpha), alone or in combination with the sensitizing agent D-galactosamine. Neonatal mice were markedly more susceptible to LPS-induced lethality but more resistant to SEB than were adults (P < .05). Mice of different ages did not differ, however, in their sensitivity to lethal activities of rTNF-alpha. Neonatal susceptibility to LPS and SEB correlated directly with plasma TNF-alpha but not IFN-gamma levels, which was confirmed by TNF-alpha and IFN-gamma blockade experiments. These data document marked age-related differences in the pathophysiology of septic shock and suggest that IFN-gamma is not an obligatory mediator of either LPS- or SEB-induced lethality in neonates.