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Homotypically conditioned media (Hom. C.M.) produced by adult Biomphalaria glabrata weighing about 600 mg and fed on pure cellulose under bacteriostatic conditions at a density of one snail per 100 milliliter of standard snail water for three days significantly enhanced the growth of juveniles. Hom. C.M. produced under the same conditions by fasting snails that were previously fed on lettuce, also had a growth promoting effect but was less potent. The growth promoting factors have a molecular weight of 500-104, and appear to act directly on the snails and not indirectly by influencing the food medium. The extent to which absolute growth rate is stimulated by the growth factors correlates well with decrements in the conductivity and calcium concentration of the media. Possible modes of action of the growth factors are discussed. They appear not to influence the relative weights of shell, or body and water content of the snails. It is suggested that the adaptive significance of the growth factors is to facilitate rapid increase in numbers of this gregarious and often fugitive species when environmental conditions are favorable.

High rates of acetylene (C 2 H 2 ) reduction (nitrogenase activity) were observed in woodroom effluent from a neutral sulfite semi-chemical mill under aerobic (up to 644 nmol of C 2 H 4 produced per ml per h) and under anaerobic (up to 135 nmol of C 2 H 4 produced per ml per h) conditions. Pasteurized effluent developed C 2 H 2 reduction activity when incubated under anaerobic but not under aerobic conditions. Activities were increased by addition of 0.5 to 3.0% glucose or xylose. Enrichment and enumeration studies showed that N 2 -fixing Azotobacter and Klebsiella were abundant, and N 2 -fixing Bacillus was present. Of 129 isolates of Klebsiella from pulp mills, lakes, rivers, and drainage and sewage systems, 32% possessed nitrogen-fixing ability.

Several different culture media were tested for their effect on weight and viability of earthworms ( Lumbricus terrestris). A medium containing pulverized newspaper, pelletted rabbit food, walnut meal, peanut oil, topsoil and coffee grounds supported life and growth for 62 weeks, and improved the condition of degenerated worms.

The types of effluent discharged by wood-processing industries and their effects on the benthic environment are described. A brief summary of the results of the Lochs Linnhe-Eil survey 1964-70 is given. Populations of the molluscs Corbula , Thyasira and Myrtea have increased in most areas, and appear to be favoured by a moderate increase in the organic input to the system. Corbula dominates in the shallower polyhaline areas, and Myrtea in the deeper mixoeuhaline areas. On sediments with a high natural leaf litter content a low diversity fauna occurs, dominated by the annelids Cirriformia , Peloscolex , Capitella and Staurocephalus , and the crustacean Idotea . The predominance of this kind of fauna has increased in its area of occurrence in recent years. Comparisons of these faunal distributions and changes with those found in surveys in other marine areas affected by wood-processing wastes and other types of organic effluents show considerable similarities in the faunal changes occurring under increased organic loading. The utility of ‘indicator’ species in the assessment of organic pollution is briefly discussed. The need for detailed information on the ecological and physiological reasons underlying the varied faunal successions which occur under conditions of pollutional stress is emphasized.

Alternaria solani produced two homogeneous exocellular polysaccharide fractions when grown in shake culture with fructose as the carbon source and the NH4NO3 concentration of the medium 1.7 g/l. Chromatographic techniques indicated that fraction I contained glucose, galactose, and glucosamine in a 2.4:1:1 ratio whereas fraction II contained glucose, galactose, and mannose in a 6.4:1:1.2 ratio. Fraction I was found at levels seven times greater than II. Total polysaccharide produced was 1.8% of the dry weight of the mycelium and 1.2% of the available carbohydrate.Growth and polysaccharide production were greatest with fructose as the carbon source. Decreasing levels of growth occurred with mannitol, glucose, and sucrose, respectively. Exocellular polysaccharides were not detected with mannitol as carbon source. At 10 days, growth on fructose is maximum at NH4NO3 concentrations of 1.5 to 2.5 g/l, but exocellular polysaccharide production is maximum at 0.8 g/l. When produced on a medium of 2.0 g/l NH4NO3 the nitrogen content of I is double that when the medium is 0.8 g/l NH4NO3. In addition the ratio of I to II is about four times greater.

Sensitive assays of histidase activity were used to follow the production of this enzyme as directed by a gene newly introduced into cells of Bacillus subtilis by transformation. Histidase activity can be detected in histidase-negative recipient cells within 1 hr after the addition of deoxyribonucleic acid extracted from histidase-positive donors. Enzyme production continues for one to two additional hours and then ceases. Histidase production in the transformed cells is fully sensitive to catabolite repression. Catabolite repression is rapidly established after transformation of recipient cells that are resistant to this form of regulation.

The cationic antibacterial proteins of rabbit PMN lysosomes have been resolved into at least five subfractions. Each of these showed substantial selectivity in its antibacterial action against several pathogenic bacteria, including two smooth and two rough Escherichia coli strains, three Staphylococcus aureus strains, one S. albus, three proteus species and four different cultures of streptococcus. Each of the subfractions possesses a different electrophoretic mobility. Amino acid analyses of the three most cationic components revealed high contents of arginine consistent with their relative electrophoretic mobilities and very high arginine to lysine ratios. Aromatic amino acids were present in very low concentrations in these proteins and their light absorption at 2800 A was correspondingly weak. The evidence of antibacterial specificity, along with marked differences in the arginine-lysine ratios, shows that the cationic antibacterial components of rabbit PMN lysosomes are biologically and chemically heterogeneous.

Soils, seeded withCoccidioides immitis in the laboratory, were baited with sterile paper strips, cotton, charcoal, chopped aster stems, horse hair, human hair and dehydrated pork liver cubes. Some growth was evident on horse and human hair, while growth was luxuriant on dehydrated pork liver. Essentially no growth ofC. immitis was observed on other baits utilized. Feasibility of isolation ofC. immitis from naturally infected soils by baiting is suggested. Spiral hyphae, noted in certain dermatophytic fungi and other Gymnoascaceae, is reported inC. immitis and possible affinity with Gymnoascaceae is conjectured.

Glycerol kinase and glycerophosphate dehydrogenase activities have been demonstrated in the obligate halophile Halobacterium cutirubrum. Both enzymes are stereospecific for the formation of only the sn-3-glycerophosphate, and are associated with the cell envelope and cytoplasmic fractions. The stereospecificity of these enzymes in the obligate halophile is thus the same as in nonhalophiles and in higher organisms. The bearing of these findings on the biosynthetic pathway for the di-O-phytanyl glycerol ether phospholipids in H. cutirubrum is discussed.

The enzyme, l -glutamine d -fructose 6-phosphate amidotransferase (EC 2.6.1.16) of Neurospora crassa , which catalyzes the formation of glucosamine 6-phosphate was shown to be subject to feedback inhibition by uridine diphosphate N -acetyl- d -glucosamine (UDP-GlcNAc). The conclusion is based on the following observations. UDP-GlcNAc, the direct precursor of chitin, did not accumulate in the cell even when its utilization for the synthesis of cell wall chitin was interrupted by the antibiotic polyoxin D, a competitive inhibitor of the chitin synthetase (EC 2.4.1.16). Furthermore, the cellular level of UDP-GlcNAc rose in a short period of time when the amidotransferase was bypassed in vivo by the addition of glucosamine to the growing medium of the fungus. The amidotransferase was purified from N. crassa approximately 85-fold. Kinetic studies showed that UDP-GlcNAc was a potent and specific inhibitor of the amidotransferase, and that it did not alter the Michaelis constant for either l -glutamine or d -fructose 6-phosphate, suggesting that the inhibitor binds at a site on the enzyme distinct from the active site.

1. 1. A method is described for the purification of a ribonuclease (polyribonucleotide 2-oligonucleotide transferase (cyclizing), EC 2.7.7.16) from mature, unfertilized eggs of the sea urchin Psammechinus miliaris . The enzyme was purified 19 000-fold with a yield of 48% with the aid of chloroform treatment, (NH 4 ) 2 SO 4 fractionation, and by chromatography on Sephadex G-100, on SE-Sephadex C-50 and on CM-Sephadex C-50. 2. 2. The enzyme had a pH-optimum at 5.3–5.5. 3. 3. The enzyme was heat labile, loosing about 50% of its activity in 3 min at 60° and pH 5.3, 70% of its activity in 3 min at 60° and pH 2.1, and 80% of its activity in 3 min at 40° and pH 9.0. 4. 4. The enzyme hydrolyzed yeast RNA completely to 2′,3′-cyclic nucleotides, and finally hydrolyzed the purine cyclic nucleotides slowly to their corresponding 3′-isomers. 5. 5. The enzyme hydrolyzed guanosine 2′-3′-cyclic phosphate about three times faster than adenosine 2′,3′-cyclic phosphate. 6. 6. The purified enzyme was found to be free of deoxyribonuclease and non-specific phosphodiesterase activity. 7. 7. A molecular weight of about 37 000 was estimated for the enzyme by comparative gel filtration experiments.

Summary The primary structure of α-bungarotoxin isolated from the venom of Bungarus multicinctus was determined. It composes of 74 amino acid residues including ten half-cystines. Comparing the sequence with those of cobras and sea snake species, striking similarities can be found, especially between α-bungarotoxin and Naja nivea α-toxin, indicating 50 % sequence homology.

1. 1. High-voltage paper electrophoretic and paper chromatographic separation of free amino acids in the pupa of Glossina palpalis gave a minimum of seventeen ninhydrin-positive spots. 2. 2. Most of these ninhydrin-reacting substances are neutral amino acids, and α-alanine has the highest concentration.

The paper-strip blood-sampling technique was evaluated for efficacy in plague passive hemagglutination tests. It is valuable for widespread serological surveys.

Homogeneous suspensions of streptomycete spores were desirable for plating after mutagenesis. Filtration through 8-μm membrane filters (Millipore Corp.) more effectively separated hyphae and spore clumps from single spores than did filtration through cotton wefts or paper.

Paper strips impregnated with stains and chemicals for bacterial staining (Gugol Scientific Corporation, distributed by Wampole Laboratories) were evaluated. The quality of staining 100 Gram-positive and 80 Gram-negative microorganisms was compared with Hucker's modification. Over-decolorization of strip-stained Gram-positive organisms was the most frequent cause of inconsistency. Paper strip “acid-fast” stain was compared with the Ziehl-Neelsen technic for 90 mycobacteria and nine Nocardia strains. Mycobacteria and Nocardia were consistently well stained by the paper strip technic; however, Nocardia were not stained by the true acid-fast method. Ninety-five clinical smears, stripstained by physicians on the wards, were evaluated. Ease of performance and stability of reagents make the paper strip technics practical for use in clinics, wards, and small bncteriologic laboratories.

A unicellular blue-green alga, Agmenellum quadruplicatum , and a filamentous blue-green alga, Lyngbya lagerheimíi , were grown heterotrophically in dim light with glucose as major source of carbon and possibly energy. The dim-light conditions did not support autotrophic growth. The two blue-green algae appeared to have the same metabolic block, namely an incomplete tricarboxylic acid cycle, as has been found in other obligately phototrophic blue-green algae. Under dim-light conditions, glucose made a greater contribution to cell constituents (amino acids) of A. quadruplicatum and L. lagerheimii than under high-light conditions.

A sequence of 107 amino acids has been determined in the single chain of the major parvalbumin (pI 4.36) from hake ( Merluccius merluccius ) muscle as a result of studies on peptides obtained after tryptic, chymotryptic, peptic and cyanogen bromide cleavages of the protein.

The most widely used method for routine antibiotic susceptibility testing of clinical isolates of bacteria is the paper-disc method. This has the advantage of simplicity, but to obtain reliable results considerable care is required both in the standardization of the procedure and in the interpretation of the zones of inhibition. A new susceptibility test method is described in this report which retains the simplicity of the paper-disc method but which enables organisms to be tested directly for susceptibility to known concentrations of antibiotic in agar. Organisms may be tested against a single concentration of antibiotic or, alternatively, a range of concentrations may be used to determine the minimal inhibitory concentration. The method utilizes stable pre-prepared materials and is not appreciably more time consuming than the conventional disc method.

HeLa cells and L cells were allowed to grow in the presence of l -methioninemethyl- 14 C so that any methylated components of the transfer RNA (tRNA) would be radioactive. The tRNA from these cells was then isolated and a complete analysis was made of the methylated bases present as minor components of the tRNA. For this purpose, the purified RNA was subjected to acid hydrolysis, and the hydrolytic products, including the methylated bases, were partially separated by chromatography on ion-exchange resins. Radioactive (methylated) compounds were then identified by paper Chromatographic analyses and, in some cases, by their chemical characteristics. Methylated bases found in relatively major quantities in both HeLa tRNA and L cell tRNA were: 1-methyladenine, 1-methylguanine, N 2 -methylguan ine, N 2 -dimethylguanine, 7-methylguanine, 5-methylcytosine, and 5-methyluracil (thymine). Methylated bases present in smaller quantities included 1-methylhypoxanthine, 3-methylcytosine, and a base thought to be 3-methyluracil. Evidence was also obtained for the presence in small amounts of 2- O -methylribose residues in both HeLa and L cell tRNA. 5-Hydroxymethyluracil was identified as a minor component of L cell tRNA, but it was not present in HeLa RNA.

The development of differential and selective media for the isolation of fungi pathogenic for man is briefly reviewed. A new primary culture technique for medical mycology is presented. This involves the use of an appropriate paper carrier impregnated with suitable concentrations of cycloheximide and chloramphenicol. The carrier, when properly placed on the surface of an agar medium inoculated with a mixed-flora specimen, favors the isolation of a wide spectrum of pathogenic and opportunistic fungi. Evaluation systems for the technique included artificial mixtures of bacteria and fungi, pooled clinical materials artificially seeded with fungi, and routine clinical laboratory specimens. Test fungi were grouped according to a selection pattern based on the extent of their outgrowth within the bacterial inhibition zone (BIZ) established by the carrier on a battery of media. Two main advantages of the antibiotics-impregnated carrier system over the antibiotics-fortified medium system are: (1) the diffusion gradient of cycloheximide allows for the selective outgrowth throughout the BIZ of pathogenic fungi resistant to it, and allows the more susceptible fungal pathogens and “opportunists” to grow out up to their levels of tolerance to the antibiotic within the BIZ; (2) the system is economically advantageous.

Cell-free extract (crude extract) of Agrobacterium tumefaciens grown on d -glucuronate or d -glucarate converts d -glucarate and galactarate to a mixture of 2-keto-3-deoxy- and 4-deoxy-5-keto- d -glucarate. These compounds are then converted by partially purified crude extract to an intermediate tentatively identified as 2,5-diketoadipate. The same enzyme preparation further decarboxylates this intermediate to α-ketoglutarate semialdehyde, which is subsequently oxidized in a nicotinamide adenine dinucleotide-dependent reaction to α-ketoglutaric acid. Since A. tumefaciens converts d -glucuronic acid to d -glucarate, a pathway from d -glucuronate to α-ketoglutarate in A. tumefaciens was determined.

1. 1. Differences in muscle proteins of the species and subspecies of the genus Xiphophorous are discernable by means of paper electrophoresis. 2. 2. The lower limit of differentiation was found at the subspecies level, as the microevolutionary divergences of isolated populations of the species maculatus could not be detected with this method. 3. 3. The electrophoretic data parallel the independently established taxonomic division of the genus Xiphophorus into three species groups. Thus, there are two extreme pattern groupings and one intermediate for both species groups and muscle proteins.

PAPER-PARTITION chromatography of tissues of genetically known strains of Drosophila melanogaster as well as those of certain plants has shown that each strain gives a constant and distinctive pattern. The chromatographic patterns of heterozygotes carrying recessive genes can be easily distinguished from those of either parental homozygous strain, even though the phenotype of the heterozygote is indistinguishable from that of the homozygous dominant. This is the case for: (a) the fluorescent patterns observed under ultra-violet light in the chromatograms of adult Drosophila melanogaster heterozygous for the following mutants: bent, eyeless2, short-vein, spineless-aristapedia, vestigial; (b) the ultra-violet-fluorescent and the ninhydrin-positive patterns of root-tip smears of heterozygotes for the mutant male-sterile2 in tomato1; (c) the ultra-violet-fluorescent and the ninhydrin-positive patterns of root-tip smears and leaf extracts of heterozygotes for the yellow-green mutant of musk melon2 (see also chromatogram).

A comparative examination of Patho-Tec reagent-impregnated paper strips and the corresponding classical biochemical tests for the identification of Enterobacteriaceae was made. Patho-Tec papers appeared to be reliable for the cytochrome-oxidase and phenylalanine-deaminase tests. The urease test papers gave false negative reactions inCitrobacter andEnterobacter isolates, but never inProteus strains. The lysine-decarboxylase test papers gave too many false positive results. These shortcomings of the strips interfere with fast and reliable identification ofSalmonella-like Enterobacteriaceae.

The structural determinants for antigen 34 in the E group salmonella are glucosyl substituents on the galactosyl units of the O antigen which has a mannosylrhamnosylgalactose repeating sequence. The temperate bacteriophage ε 34 brings about the production of antigen 34. It has been shown here that glucose is transferred from uridine diphosphate glucose to the O antigen via a glucosyl-lipid intermediate in a two-step reaction. Glucose is linked through carbon 1 to the lipid by a phosphodiester bridge, the glucosyl bond having the β-anomeric configuration. The lipid is a C 55 -polyisoprenoid alcohol, each isoprene unit having one double bond. It is the same lipid which is involved in the synthesis of the O antigen repeating sequence.

A description is given of a simple method of determining the sensitivity of bacteria to sulphonamides by means of impregnated blotting-paper disks applied to nutrient agar prepared from broth freed from sulphonamide antagonists by incubation with lysed horse red blood cells.With organisms sensitive to the selected sulphonamide, a zone of inhibition of growth will occur, the diameter of which is related to the concentration of the sulphonamide necessary to inhibit growth. Sensitivity to several sulphonamides can be determined simultaneously.The impregnated disks can be stored without loss of potency.

SUMMARY: Some 300 strains of bacteria representing twenty genera were grown on an acid-hydrolysed casein medium. Using the paper chromatographic technique of Woiwod (1949) a preliminary survey was made of the amino-acid and polypeptide composition of the bacterial culture filtrates. It was proved that: (a) changes may occur in the filtrate chromatogram which have group or species significance; (b) bacteria with simple nutrient requirements, i.e. which utilize ammonia, do not affect the chromatogram in the initial growth stage; (c) whenever the chromatogram is affected serine is the first amino-acid to be metabolized; (d) Gram-positive bacteria eliminate the aspartic acid spot but leave the basic amino-acid group unaffected, and the reverse occurs with Gram-negative bacteria; (e) many bacteria synthesize ninhydrin-positive material, presumably polypeptide, the synthesis of a given kind of polypep-tide being sometimes associated with a particular group or species of bacteria. By a disintegrator technique it was demonstrated that bacteria store many free amino-acids inside the cell.

A new and rapid method for the identification of enteric bacilli directly from Hektoen enteric agar plates is described. This procedure is based on the use of reagent-impregnated paper strips and requires only 4 to 6 hr. to obtain data from 13 biochemical reactions. Six to 20 well isolated colonies which are morphologically similar are required for this procedure. Nine hundred forty-three clinical specimens were examined both by the direct method from Hektoen enteric agar and by the conventional method of selecting representative colonies from either eosin-methylene blue or Salmonella- Shigella agars, inoculating a triple sugar iron agar tube, and then carrying out biochemical testing. A total of 1,037 organisms was isolated and correctly identified by the direct method and 1,046 by conventional methods. Each biochemical test carried out with paper strips was controlled by standard media, with a 99.3% correlation between results. Of the 943 clinical specimens examined, 842 (89%) were acceptable for the direct method. The remaining 101 either had too few colonies present or were improperly streaked. The average time required to obtain significant biochemical data by the direct method was 5 hr. after isolation on the Hektoen enteric agar plates, while the average time needed to obtain the same biochemical data using conventional methods was 48 hr. There was less than a 0.05% failure of the direct identification system to allow either isolation or identification, compared with conventional systems described in the literature.4

The aerobic metabolism of β-amino-n-butyric acid was studied with cell-free extracts of a strain of Pseudomonas putida isolated in pure culture through enrichment from a liquid medium containing DL-β-amino-n-butyrate as the sole energy source. The extracts catalyze the decomposition of L-(+)-β-amino-n-butyrate in the presence of pyruvate. D-(−)-β-amino-n-butyrate is not decomposed and does not inhibit the deamination of the L-isomer. The products of the transamination reaction are aceto- acetate and alanine. Experiments on the substrate specificity of the transaminase activity showed that other β- and γ-amino acids can serve as efficient amino donors, whereas corresponding α-amino acids are poor substrates. The further metabolism of acetoacetate is discussed on the basis of the demonstration of acetoacetyl-CoA: succinyl-CoA transferase and acetoacetyl-CoA thiolase activities in the crude extracts as well as activities of glyoxylate cycle enzymes. A complete reaction scheme for the ultimate conversion of β-amino-n-butyric acid to succinate is presented and discussed.

The test paper here described makes it relatively easy to choose the antibiotic best suited for treatment of a given bacterial infection. Each type of test paper bears both a culture medium and an antibiotic and is supplied, dry and sterile, in a transparent envelope. For a given test, the paper is wetted and inoculated and the envelope with its contents is incubated. It is not necessary to wait for the appearance of visible colonies because the metabolic activity of the bacteria is detected by an indicator (triphenyltetrazolium chloride) which is colorless until reduced to a bright red dye by bacterial enzymes. The reliability of the new test was established by a comparative study with other methods in 100 clinical cases. The test paper is easily stored, and the entire unit can be incinerated after use. It is therefore useful in general office practice and should help to make sure that each patient receives the most effective antibiotic.

The direct lytic factor (DLF) from the venom of Ringhals ( Haemachatus haemachates ) was isolated and purified by successive application of trichloroacetic acid and salt precipitation. The purified DLF is homogeneous by ultracentrifugal and electrophoretic criteria and is about twice as active as the material isolated previously by paper electrophoresis. DLF is a single-chain protein with a molecular weight of 7000. It contains 57 amino acid residues cross-linked intramolecularly by 4 disulfide bridges. Leucine is in the amino terminal position, and serine in the carboxyl terminal position of the protein. DLF causes inhibition of growth in some bacteria.

Biologically active 14 C-labeled purified protein derivative ( 14 C-PPD) has been prepared from the culture filtrates of seven species of mycobacteria, namely Mycobacterium tuberculosis Johnston strain (PPD), M. bovis BCG (PPD-BCG), M. avium (PPD-A), M. kansasii (PPD-Y), M. intracellulare (PPD-B), M. scrofulaceum (PPD-G), and M. fortuitum (PPD-F). These mycobacteria were grown in a culture medium containing a mixture of 14 C-labeled amino acids. The yield and specific radioactivity of the PPD, of the nucleic acid, of the bacterial cells, and of the CO 2 developed during growth have been determined for each of the seven species of mycobacteria. Although the yields of 14 C-PPD antigens differed greatly for the different species of mycobacteria tested, their specific radioactivities were similar. The 14 C-PPD antigens have been used as a means to measure their adsorption to glass. When glass ampoules containing dilute solutions (0.001 mg of PPD per ml) of these PPD antigens (PPD, PPD-BCG, PPD-A, PPD-Y, PPD-G, PPD-B, and PPD-F) were stored for 12 months at 5 C, it was found that they all adsorbed equally well to glass surfaces. In fact, regardless of the origin of the PPD, a loss due to adsorption of about 90% occurred during the first month of storage, and thereafter the PPD content remained practically constant for the rest of the duration of the storage period. The addition of 0.0005% Tween 80 to the PPD solutions effectively reduced the adsorption to glass of most PPD antigens. However, adsorption of PPD-BCG was not quite so effectively prevented, even when the Tween 80 concentration was increased from 0.0005 to 0.0005%.

A procedure is described for the preparation of crude freeze-dried galactose oxidase from the growth medium of the fungus Polyporus circinatus Fr. The crude and stable dry enzyme preparation is used for making test papers that are specific for galactose and certain galactose-containing sugars. The enzyme galactose oxidase catalyzes the oxidation of carbon-6 of galactose or the galactose moiety of certain oligosaccharides from an alcohol to an aldehyde. The test papers are useful for semiquantitative screening procedures for galactose, raffinose, and stachyose. Solutions containing as little as 0.01% galactose or 0.04% raffinose can be detected in less than 10 min. Ion-exchange methods are described for the elimination of the interfering compounds-ascorbic acid, chlorides, and fluorides.

Novobiocin-supersensitive (NS) mutants which could not grow on plates containing 40 μg or less of novobiocin per ml were isolated from Escherichia coli strain JE1011 (derived from E. coli K-12). Most of these NS mutants were found to have incomplete lipopolysaccharides (LPS), and they lack phosphate diester bridges in their backbone structure, with or without total loss of heptose, to which the phosphate diester is linked, and consequently lack external outer-core oligosaccharides. The phosphate diester bridges in the LPS backbone are apparently very important in forming a cell surface structure resistant to the penetration of antibiotics such as novobiocin, spiramycin, and actinomycin D. NS mutants, with incomplete LPS, lacking phosphates in their backbone structure were found to be resistant to phage T4, and those which also lacked heptose were resistant to phages T4 and T7. In contrast to the generally accepted idea that resistances to phages T3, T4, and T7 are linked genetically, no NS mutant was found to be resistant to T3. The possible structures of the receptors for T4 and T7 are discussed. The positions of novobiocin-supersensitive genes on the chromosome of several of the NS mutants defective in LPS were mapped. The genes were designated lpcA (between ara and lac ) and lpcB (between 55 min and 60 min). The latter seemed to be a group of several related genes.

An adaptation of a moist-chamber method is described whereby Verticillium albo-atrum, V. dahliae, and V. nigrescens can readily be isolated from herbaceous and woody hosts and easily identified. Segments of infected stems, petioles, and roots cut transversely can be observed microscopically at daily or frequent intervals to determine the origin of outgrowing fungal hyphae in the absence of troublesome contaminants.

A 10-minute test, utilizing a urease paper-reagent strip (PATHO-TEC), for differentiating Klebsiella and Enterobacter species is described. By using a heavy suspension of organisms and 50 C temperature for incubation, 93% of Klebsiella strains (186/200) were positive and 95% of Enterobacter strains (190/200) were negative with this testing system. The rapid nature of the test (10 min), the facility with which it can be carried out, and the ease with which the strips can be stored and handled may make this a useful aid for the clinical microbiologist.

The reaction of Paramecium caudatum to solutions containing the ash of cigarette paper was consistent with the response of Paramecium aurelia previously reported. After this confirmation, both these species of Paramecium were used as test organisms during a search for the causative agents for the "Paramecium reaction". A qualitative spectrochemical analysis of cigarette paper ash showed that its chief constituent is calcium (97%) with 12 other detected elements present at levels too low to elicit any response from paramecia. Hydroxyl ions in concentrations equivalent to 0.001 M Ca(OH)2, 0.0008 M KOH, or 0.002 M NaOH simulated but did not duplicate the effect of standard cigarette paper ash solution (as of one cigarette paper in 20 ml water). While neutralization caused the three hydroxide solutions to lose their toxicity, the toxicity of cigarette paper ash solution was not appreciably affected by neutralization. Equivalent solutions of facial tissue, filter paper, and a paper towel, burned the same way as cigarette paper, were used as controls. Each of them affected paramecia differently and none simulated the Paramecium reaction. Further, a comparison between ashes from a paperless cigarette, a whole cigarette, and one with two extra roll-your-own wrappers demonstrated a dependence of the Paramecium reaction on cigarette paper ash as well as a direct correlation between the reaction intensity and the amount of cigarette paper ash present.

SUMMARY An improved method for determining cellulolytic activity in anaerobic bacteria is described in which the disintegration of a filter paper strip denotes activity. By inoculating the paper-containing media from dilutions of material such as rumen contents estimates of the numbers of cellulolytic bacteria in the original material may be made. The method can also be used for determining cellulolytic activity of pure cultures. Morphology and other properties of the bacteria may be determined.