The growth of bacteria is often enhanced by addition of carbon materials such as graphite or activated charcoal to the growth medium. In this work, bacterial strains that strictly require such carbon materials under the ordinarily lethal stress caused by high concentrations of salt were isolated. The organisms were gram-positive, spore-forming, sugar-nonfermenting aerobic bacilli and were provisionally designated ''Bacillus carbophilus'' Kasumi after examination of their phenotypic traits. The growth-and germination-promoting effects of graphite and activated charcoal were demonstrated either quantitatively on agar plates containing fine crystals of the carbon materials mixed with a nonpermissive growth medium or qualitatively on agar plates on nonpermissive growth media half-covered with fine carbon particles. Further experiments demonstrated a novel feature of the phenomenon; i.e., the ability to induce colony formation on the nonpermissive plate was transmissible through the air, as well as through plastic or glass barriers. The mechanism probably involves transmission of physical signals regulating cell growth.The unique biological effects of carbon materials, such as graphite and activated charcoal, have frequently been recognized: e.g., charcoal powders are often applied to the soil to enhance plant growth or used to facilitate the proliferation of bacteria such as Neisseria gonorrhoeae (4), Haemophilus pertussis (7), and Legionella pneumophila (3); artificial cardiac valves made of carbon displayed antithrombogenecity (1, 5); and carbon tooth implants displayed a favorable affinity to gingival tissue (10). It seems to be generally accepted that these carbon materials act indirectly on living organisms, e.g., by adsorbing inhibitory substances from the medium. We report here that carbon exerts a novel effect on the proliferation of at least some bacteria, involving an unexpected mechanism. MATERIALS AND METHODSCarbon and other materials. Graphite preparations were provided by the Toyo Carbon Co., Osaka, Japan (graphites A to C), and the Mitsubishi Pencil Co., Tokyo, Japan (graphites 1 to 4). Their sources and properties are listed in Table 1. Two activated-charcoal preparations, one washed with HCl and the other washed with HCl and then neutralized, were Sigma products. Aluminum oxide (Wako Pure Chemicals, Kyoto, Japan) and levigated alumina (Norton Co., Worcester, Mich.) were commercial products. Glass powders were prepared by grinding microscope slide coverslips in a ceramic mortar, washed repeatedly with water, and sterilized by autoclaving. Carbon materials scattered on agar plates were used after exhaustive sterilization by heating at about 700ЊC for 1 min on a gas burner. In other cases, they were mixed with nutrient agar and autoclaved at 120ЊC for 15 min.Bacteria and growth conditions. Isolation and preliminary characterization of bacteria with high graphite requirements are described below. These are Bacillus strains and are maintained in our collections (Tokai University and Fujisawa Pharmaceutic...

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Gluconate was fermented selectively by the Bijidohacterium adolescentis group and some species of other genera, including Clostridium clostridiiforme, C. innocuum, Propionibacterium acnes, Megasphaera elsdenii, Enterococcus jaecium and Klebsiella pneumoniae; however it was not utilised by most other bacteria including the Bacteroidaceae. No other organic acid salts were utilised by B. adolescentis. These salts weakly inhibited the growth of C. perjringens in vitro, as did gluconate. The absorption rate of gluconate from the ligated small intestinal loop in rats was 19.9 per cent under conditions when 100 per cent of glucose was absorbed. The effects of ingestion of gluconate on human faecal bacteria was studied in ten healthy adult males. They ingested 9 g/d or 3 g/d of glucono-6-lactone (anhydride of gluconic acid). With the 9 g/d ingestion, the number of bifidobacteria significantly increased (P<0.001), whereas C. perfringens decreased and Enterobacteriaceae remained constant. The concentrations of bifidobacteria also increased ( W 0 . 0 5 ) following 3 g/d ingestion.

The in vitro susceptibilities of eight isolates of Treponema hyodysenteriae from pigs naturally infected with swine dysentery between 1976 and 1983 were determined by an agar dilution technique. Carbadox, olaquindox, tiamulin, metronidazole, furazolidone, and monensin were the most active against these field isolates regardless of the year of recovery. The influence of inoculum size on the MICs against four reference strains of T. hyodysenteriae was studied. Various degrees of activities of ampicillin and lincomycin were found, depending on the inoculum size. The effect of successive in vitro subcultures on the susceptibility of a reference strain of T. hyodysenteriae was examined. The strain resistant to tylosin became susceptible to the drug.Treponema hyodysenteriae is considered the primary causative agent of swine dysentery, a disease characterized by severe bloody diarrhea (8,24). Determination of the susceptibility of T. hyodysenteriae to antimicrobial agents is of great importance in the selective use of chemotherapeutics, the evaluation of new antimicrobial agents, and the development of drug resistance through continuous use of antimicrobial agents against field isolates (10,15,18,26,27). A commonly used method for in vitro susceptibility testing of the organism is an agar dilution technique (15, 27). However, the MICs are sometimes markedly influenced by the test conditions (4, 23). Inoculum size would be a key factor affecting the amount of antimicrobial agent required to inhibit the organism in vitro, because a large inoculum is required for the propagation of T. hyodysenteriae (13). Because the reference strain, as an indicator strain for MIC determination, should usually be maintained in vitro, successive subcultures in vitro may also affect its MICs since successive subcultures often cause decreased pathogenicity in vivo (12).The purpose of the present study was to determine the in vitro activities of antimicrobial agents currently in medicinal and veterinary use and to investigate the influence of inoculum size and the effect of in vitro subcultures on the susceptibility of T. hyodysenteriae. were used to study the influence of inoculum size and the effect of successive subcultures on in vitro susceptibilities. Eight field isolates were examined for the activities of antimicrobial agents. These isolates were individually isolated from mucosal scrapings of colons or diarrheal feces with mucus and blood from pigs naturally infected with swine dysentery at different localities in Japan. Four isolates were recovered during sporadic outbreaks from 1976 to * Corresponding author.1979, and four others were recovered from 1980 to 1983. They were maintained in vitro in our laboratory. Eight field isolates underwent less than 10 successive subcultures; S73/2, ATCC 31212, and ATCC 27164 underwent less than 50 successive subcultures; and DJ70 underwent both less than 50 and more than 150 successive subcultures. Prophylactic and therapeutic regimens for swine dysentery are unknown.Media. An anaerobic diluent ...

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