Lot Of Medium Research Articles

A coupling, stabilizing, and shaping strategy for breast ultrasound computed tomography (USCT) with a ring array transducer

Breast ultrasound computed tomography (USCT) has been gradually promoted to clinical application after years of rapid development. Compared with the traditional handheld ultrasound scanning method, the scanning plane of USCT is fixed at the coronal plane, and the scanning path is designed in advance; the acoustic window is not in direct contact with the breast, a lot of coupling medium (usually degassed water is used to fill the gaps between the probe and breast. The clinical application of breast USTC faces challenges: (1) the processes of water degassing, heating, filling, draining, and cleaning prolong the entire scan cycle and reduce patient throughput. (2) The breast is not stabilized and slight movements of the breast may cause motion artifacts in the USCT images. (3) The non-normal incidence of ultrasound into the breast causes reflected and transmitted signals received with a low signal-to-noise ratio (SNR) or even unable to be detected. This article proposes a coupling, stabilizing, and shaping strategy for the clinical application of USCT with a ring array transducer. The solid gel coupling agent (SGCA) is applied for coupling, and a set of SGCA moldings is designed to stabilize and shape the breast during scanning, the breast shape and size which vary from person to person are simplified into several models. The preparation time is reduced to less than 1 min by replacing disposable moldings. The results show that the breast after shaping is close to round in the coronal plane, and slopes of the breast skin are limited in the sagittal and transverse planes, the breast subcutaneous tissue (fat and glands) has a better contrast-to-noise ratio (CNR) and can be better distinguished in the reflection images than that of the breast without shaping. The mean value of the raw beamformed data which represents the reflection signal amplitude of breast subcutaneous tissue after shaping shows 1.5 times that of the breast without shaping, the signal-to-noise ratio (SNR) of the raw transmission signal data after breast shaping is overall higher than that of the breast without shaping. The application of SGCA moldings for breast coupling, stabilizing, and shaping also benefits establishing a standardized scanning process, the standardized diagnosis of the breast lesion, and the localization of breast lesions.

Redetermination of the Depositional Age of the Haerdaban Group in the Northern Margin of the Yili Block, Western Tianshan, NW China: Implications for Regional Tectonics and Pb‐Zn Mineralization

AbstractThe Yili Block in the Western Tianshan orogen is a key area for understanding the early crustal formation and evolution of the Central Asian orogenic belt, due to the widely‐distributed Precambrian rocks. Also, it hosts a lot of medium– to large‐scale sedimentary exhalative (SEDEX) Pb‐Zn deposits that mainly occur in Proterozoic metamorphosed clastic‐carbonate rocks. In this study, LA‐ICP‐MS U‐Pb analyses were carried out on detrital zircons in siltstones of the Precambrian Haerdaban Group in the Haerdaban Pb‐Zn deposit and magmatic zircons in the diorite dyke that cuts through the strata and orebodies. The maximum depositional age of the siltstones was determined to be about 604 Ma, the diorite having formed at approximately 500 Ma. As such, the Haerdaban Group was most likely formed in the Neoproterozoic Sinian, rather than the previously considered Mesoproterozoic Changchengian. Detrital materials of the Haerdaban Group were mostly derived from the Nanhua–Sinian mafic dykes and granitic rocks around Lake Sayram at the northern margin of the Yili Block. It is proposed that the Yili Block, together with the Kazakhstan and Central Tianshan blocks and the Tarim Craton, might all pertain to the same Rodinia supercontinent, which has great potential for targeting large to super‐large SEDEX Pb‐Zn deposits.

Serum-free human MSC medium supports consistency in human but not in equine adipose-derived multipotent mesenchymal stromal cell culture.

For clinical applications of multipotent mesenchymal stromal cells (MSCs), serum-free culture is preferable to standardize cell products and prevent contamination with pathogens. In contrast to human MSCs, knowledge on serum-free culture of large animal MSCs is limited, despite its relevance for preclinical studies and development of veterinary cellular therapeutics. This study aimed to evaluate the suitability of a commercially available serum-free human MSC medium for culturing equine adipose-derived MSCs in comparison with human adipose MSCs. Enzyme-free isolation by explant technique and expansion of equine and human cells in the serum-free medium were feasible. However, serum-free culture altered the morphology and complicated handling of equine MSCs, with cell aggregation and spontaneous detachment of multilayers, compared to culture in standard medium supplemented with fetal bovine serum. Furthermore, proliferation and the surface immunophenotype of equine cells were more variable compared to the controls and appeared to depend on the lot of the serum-free medium. Particularly the expression of CD90 was different between experimental groups (P < 0.05), with lower percentages of CD90+ cells found in equine MSC samples cultured in serum-free medium (5.21-83.40%) compared to standard medium (86.20-99.50%). Additionally, small subpopulations expressing MSC exclusion markers such as CD14 (0.28-11.60%), CD34 (0.00-9.87%), CD45 (0.35-10.50%), or MHCII (0.00-3.67%) were found in equine samples after serum-free culture. In contrast, human samples displayed a more consistent morphology and a consistent CD29+ (98.60-99.90%), CD73+ (94.60-98.40%), CD90+ (99.60-99.90%), and CD105+ (97.40-99.80%) immunophenotype after culture in serum-free medium. The obtained data demonstrate that the serum-free medium was suitable for human MSC culture but did not lead to entirely satisfactory results in equine MSCs. This underlines that requirements regarding serum-free culture conditions are species-specific, indicating aneed for serum-free media to be optimized for MSCs from relevant animal species. © 2017 International Society for Advancement of Cytometry.

OP-003 - A review of commercial MEA testing and plea for informative MEA certificates of analysis

OP-002 – Table 1. Post warming re-expansion time, hatching and cell survival rates Treatment group Total number Mean time to Survival rate Hatching by Hatched by Total number of Mean total cell Mean cell survival of embryos re-expand (h) ± SEM (%) 16 h (%) 24 h (%) embryos stained number ± SEM (%) ± SEM CONTROL short 35 1.2±0.33 94.3 55.9 13.8 17 65±3.8 97.0±0.8 LAC short 32 5.8±0.52 90.6 90.6 57.1 12 53±5.2 96.4±1.9 MAC short 33 4.0±0.60 100.0 51.5 17.2 23 71±4.4 92.8±3.7 CONTROL long 33 2.9±0.60 100.0 42.4 15.2 15 65±6.4 90.7±4.4 LAC long 35 7.6±0.60 97.1 91.4 31.4 8 72±9.5 94.2±1.4 MAC long 31 5.6±0.71 100.0 45.2 12.9 24 72±4.0 95.9±1.0 Significant differences for expansion and hatching rates are indicated in Figures 2 and 3. OP-003 A review of commercial MEA testing and plea for informative MEA certificates of analysis Ronny Janssens1, Greta Verheyen1, Rita Cortvrindt2 1Centre for Reproductive Medicine, UZ Brussel, Brussel, Belgium; 2EggCentris BVBA, Anderlecht, Belgium Introduction: ASRM or ESHRE guidelines require that material in contact with gametes or embryos should be non-toxic and tested with an appropriate bioassay. In IVF centres, in-house MEA testing of every lot of disposables or culture medium is not realistic. Laboratories depend on manufacturers and should be able to understand how their MEA tests are performed. Variables necessary to understand a certificate of analysis (COA) and statement “MEA tested” are detailed information on exposureand test protocols. Unfortunately, information on COAs is limited to “MEA tested” and acceptance criteria. Detailed exposure protocol or testconditions are never provided. In 2013, we mailed our suppliers or manufacturers and requested information on their MEA testprotocols and original COA’s of the MEA tests performed. Results: 24 COA’s from 11 different companies were received. MEA testprotocol was either not specified (n=4), a one cell assay (n=17) or a two cell assay (n=1). Limited info on exposure (n=4) and test conditions was disclosed (n=7). Different assay end-points and acceptance criteria were used: percentage blastocyst development on day 5 (n=12), day 6 (n=3) or without specification of the day of evaluation (n=6). On 3 COAs, no endpoint was given. Acceptance criteria were >80% (n=15), >75% (n=5), >70% (n=2) or not specified (n=2). Conclusions: Current commercial MEA testing is not transparant and company’s statement “MEA tested” of limited value. IVF laboratories should challenge suppliers and insist on certified testlaboratories, sensitive, standardized and disclosed MEA test conditions, exposure protocols and acceptance criteria and should select suppliers based on this.

Expression of antimicrobial peptides and proteins in epidermis equivalents exposed to salt water and narrowband ultraviolet B radiation.

Expression of antimicrobial peptides and proteins in epidermis equivalents exposed to salt water and narrowband ultraviolet B radiation.

Multicentre determination of quality control strains and quality control ranges for antifungal susceptibility testing of yeasts and filamentous fungi using the methods of the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antimicrobial Susceptibility Testing (AFST-EUCAST)

A multicentre study involving seven laboratories was performed using techniques recommended by the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antimicrobial Susceptibility Testing (AFST-EUCAST) to evaluate and propose quality control ranges and strains for susceptibility testing of fermentative yeasts and filamentous fungi. Participating laboratories tested the susceptibilities of a panel of 12 encoded isolates to amphotericin B, flucytosine, fluconazole, itraconazole, voriconazole and posaconazole. In total, 15 lots of assay medium were tested, with one lot being common to all laboratories, and 18 144 MIC values were determined. Intra- and inter-laboratory agreements and intra-class correlation coefficients (ICCs) of the results for each drug/strain/lot combination were calculated. An average value of 85% agreement was selected for validation purposes. The average percentage of intra-laboratory agreement was 90-95%, with ICC values of 0.90-0.95 (p <0.01). Inter-laboratory reproducibility was also high, with 92% agreement and an ICC of 0.97 (p <0.01). The reproducibility was somewhat better with the common lot of assay medium (96% agreement) than with the different lots (91% agreement), but this difference was not significant. Two isolates that showed trailing growth had agreement percentages below the 85% limit selected for validation purposes and were therefore excluded from the panel of quality control strains. The recommended EUCAST methodologies were found to be highly reproducible and reliable for susceptibility testing of yeasts and filamentous fungi. Ten isolates are proposed for use as quality control strains with these EUCAST procedures.

Variations in Barbour-Stoenner-Kelly Culture Medium Modulate Infectivity and Pathogenicity of Borrelia burgdorferi Clinical Isolates

The effects of variations in Barbour-Stoenner-Kelly (BSK) medium on the infectivity and pathogenicity of Borrelia burgdorferi clinical isolates were assessed by retrospective and prospective studies using a murine model of Lyme borreliosis. Thirty of 35 (86%) mice infected with any of six virulent B. burgdorferi clinical isolates grown in a BSK-H medium developed clinically apparent arthritis. By contrast, arthritis was observed in only 25 of 60 (42%) mice inoculated with two of these B. burgdorferi strains grown in a different lot of BSK-H medium (P < 0.001). In a prospective study, mice inoculated with a B. burgdorferi clinical isolate grown in a BSK medium prepared in-house produced significantly greater disease than those injected with the same isolate cultured in BSK-H medium (P < 0.05). The attenuated pathogenicity is not due to the loss of plasmids during in vitro cultivation. The data suggest that variations in BSK medium have a significant impact on the infectivity and pathogenicity of B. burgdorferi clinical isolates.

Effects of Fruits Loading, Thinning Time, and Water Stress on Medium-size and Regular Shaped Fruit of `Niitaka' Pear

Consumers in the United States. and the European Union prefer to purchase medium-sized and symmetrical pears, while most Koreans prefer fruit that is as large as possible. This study was carried out to determine the effect of fruit loading, thinning time, and water management at full bloom stage on the number of seed and size and shape of fruit. As fruit loading increased and the time of fruit thinning was delayed, there was a decrease in fruit weight. The rate of fruit weight under 450 g was 41.7% in the treatment of 30% increase of fruit loading compared to control. There was an increasing tendency of symmetry fruits as the increase of fruit loading. By water stress treatment for 30 days after full bloom, a lot of medium sized fruit were harvested. The rate of symmetrical fruits was increased from the fruit, which held nine to ten seeds per fruit as well as uniformed seed development. Therefore, these results suggested that the number of seed s per fruit showed a close relationship to fruit shape, but water stress and fruit thinning time did not affect the fruit shape.

Multisite reproducibility of results obtained by two broth dilution methods for susceptibility testing of Mycobacterium avium complex.

A multicenter study was conducted to assess the interlaboratory reproducibility of susceptibility testing of Mycobacterium avium complex (MAC) by broth microdilution using two different media (cation-adjusted Mueller-Hinton broth with 5% oleic acid-albumin-dextrose-catalase and 7H9 broth with casein) and by macrodilution using the BACTEC 460TB and 12B media at pH 6.8 and 7.3 to 7.4. Ten well-characterized strains of MAC (four macrolide susceptible, six macrolide resistant) were tested against clarithromycin and azithromycin (the latter only by BACTEC 460TB, pH 6.8). At each site, strains were tested against clarithromycin three times on each of three separate days (nine testing events per isolate) by using a common lot of microdilution trays and BACTEC 12B medium, pH 6.8; strains were tested once on three separate days against clarithromycin in 12B medium at pH 7.3 to 7.4 and against azithromycin. Agreement among MICs (i.e., mode +/- 1 twofold dilution) was 100% for all strains and both drugs when BACTEC 460TB was used, regardless of the pH of the medium, but varied when microdilution with either medium was used, particularly with susceptible strains. Agreement based on interpretive category, with NCCLS-recommended breakpoints, was 100% for all strains with the BACTEC 460TB method (both drugs and both pH values) and with microdilution using 7H9 broth. With microdilution and Mueller-Hinton broth, agreement by interpretive category was 100% for eight isolates and >90% for two; errors occurred only in laboratories where personnel had minimal experience with this technique. MAC susceptibility testing may be performed by broth macrodilution or microdilution at either pH, with NCCLS-recommended interpretive breakpoints. However, because visual interpretation of broth microdilution end points is subjective, it is more prone to reader error; therefore, this method requires greater expertise than the BACTEC 460TB. Both techniques require appropriate validation and continued documentation of proficiency.

Lot-to-lot variability of antibiotic medium 3 used for testing susceptibility of Candida isolates to amphotericin B.

We have previously shown that use of antibiotic medium 3 in the microdilution variant of the M27-T test method permits detection of amphotericin B-resistant Candida isolates. As this medium is not standardized and our initial work used only a single lot of antibiotic medium 3, we studied the lot-to-lot variability of three commercial lots of antibiotic medium 3 obtained from two sources. The MICs obtained with the new lots were lower than those of with the original lot, but the new lots still consistently separated putatively resistant and putatively susceptible isolates and this permits proposal of possible breakpoints for this assay system.

Reproducibility of disc susceptibility tests with Haemophilus influenzae

Triplicate susceptibility tests were performed in each of three laboratories with 45 strains of Haemophilus influenzae and a single lot of Haemophilus test medium (HTM) agar plates. Using clarithromycin, erythromycin and chloramphenicol discs. zone sizes varied over ranges averaging only 4.3-5.8 mm. Ampicillin zone sizes were more variable, especially when beta-lactamase-producing strains were being tested, but the latter strains were consistently categorized as being resistant. A 94% interpretive consistency was observed with the two macrolides.

The Characteristics of Cotton Textile Factory Owners in Several of the Villages of Senboku-gun, Osaka Prefecture in the 1910's

As a result of the rapid expansion of the cotton textile production in the Izumi Region, the production in Osaka Prefecture grew and led the national textile production from the 1900's to the 1920's. At that time a lot of medium and small textile factories were established and the cotton textile industry was formed in the Izumi Region. In this paper, the author investigates what kind of farmers became textile factory owners, the driving force for the industrialization of the rural area in Senboku-gun during the Meiji-Taisho Eras, and also explains the factors which contributed to the differences between the distribution pattern of the “Shiro-Momen” (non-dyed cotton cloth) factories and that of the cotton blanket factories in the same area. The results are as follows:From an analysis of the imposition lists on the household tax (a kind of local tax at that time) at 4 villages, It can be seen that the main class of the textile factory owners were small landlords or landed farmers who owned 5-20 tan (1 tan is about a fourth acre). And as one approaches the inland villages of Hakata-son, Sinoda-son and Gosho-son away from the coastal village Kamijo-son, it can be seen that the main axis of the class rises from 5 tan to 5-10 tan or 10-20 tan. It seems that the economic structure of those villages is certainly reflected in the appearance of many textile factories.The textile factories were not distributed uniformly in the rural area. The number of factories varied greatly from settlement to settlement in the same village. It seems that the response to the textile industry was influenced not only by the economic situation at each settlement, but also by the villager's sense or the presence of a pioneer at each settlement. Also it shows a tendency for the factories to specialize in one product at each settlement, and the cotton blanket factories increased more and more at settlements nearer to Otsu-son.The “Shiro-Momen” factories which spread out widely to the south of Senboku-gun, rapidly increased after the late 1900's. The geographical location was a main reason for the increase in this area, and, consequently the conditions for establishing textile factories were fostered at that time. There were two main conditions in this area: The first was that the small landlords or landed farmers who were short of funds were helped to establish factories by developing or diffusing the cheap power looms and motors in this region. The other was that a lot of the small landlords or landed farmers who would become textile factory owners lived in this area.It seems that the distribution of the cotton blanket factories were restricted within the surrounding area of Otsu-son because of production techniques and their functional relation to the cotton blankets. Exactly speaking, production system of the blankets had a more complicated division of labor than the“Shiro-Momen”production. Also, Otsu-son was the birthplace and the center of blanket production. Therefore, we may presume that the conditions of transportation and communication prevented the distribution of those factories from expanding far from Otsu-son at that time. Also, another factor is that the smaller farmers in this area could enter into the business, because even small scale weaving of the cotton blankets certainly made profits.

Physico-Chemical Processing Options

This paper describes physico-chemical treatment of inorganic toxic wastes at the centralized waste treatment facility in Denmark. The paper also reports on some alternative processes and development trends for detoxification of this type of waste. Denmark was the first country to introduce centralized treatment of hazardous waste on a national scale. The centralized chemical treatment plant in Denmark, called "Kommunekemi", is located at Nyborg in the middle of the country. Besides a physico-chemical treatment plant for inorganic waste, it also operates incinerators for organic hazardous waste, waste oil recovery and a controlled landfill. Industry in Denmark is characterized by a few big companies and a lot of medium and small sized companies. In most cases, Danish medium sized companies would be looked upon as small ones when comparing on an international basis. The big facilities normally have wastewater treatment plants of their own and may just deliver small quantities of some odd types of wastes to the centralized plant, Kommunekemi. The smaller facilities, which do not have waste treatment, deliver all their waste for external treatment at Kommunekemi. Naturally this system encourages the waste producers to minimize their waste production by re-circulation and/or re-use as far as possible with respect to production quality and internal and external environment. Centralized waste management systems of the same type as in Denmark are also in operation in Sweden and Finland.

Studies of metabolic changes in cell cultures infected with four serotypes of dengue fever viruses by frequency-pulsed electron-capture gas—liquid chromatography

Monkey kidney cell cultures were infected with four serotypes of dengue viruses, and the supernatant fluids of the cell cultures were extracted for amines, alcohols, carboxylic acids, and hydroxy acids. The derivatized extracts were then analyzed by frequency-pulsed electron-capture gas—liquid chromatography (FPEC—GLC). FPEC—GLC profiles of the hydroxy acids showed peaks that were different for different serotypes and the FPEC-GLC carboxylic acid profiles differed from the control medium. These differences were reproducible when the same lot of medium was used. There were differences in profiles between lots of control media due apparently to different fetal bovine sera used in the growth medium. Therefore, the same lot of medium was necessary to reproduce profiles. The data obtained from the study indicate that FPEC—GLC can be used to detect changes in cellular metabolism caused by viral infection, and that these metabolic changes might be useful for detection of genetic differences in viruses as reflected by detectable changes in the metabolism of the infected cell.

Growth and aflatoxin production by Aspergillus parasiticus when in the presence of Streptococcus lactis.

Streptococcus lactis was grown with Aspergillus parasiticus in modified APT broth. Three inoculation procedures were used: (a) S. lactis was grown 3 days, then conidia of A. parasiticus were added (SLAP), (b) both organisms were added simultaneously (ST) and (c) A. parasiticus was grown 3 days, then S. lactis was added (APSL). At 3, 6 and 10 days of incubation, contents of flasks were analyzed for growth of each organism, pH of broth and aflatoxin content. S. lactis did not survive past 3 days when grown alone. In ST cultures, S. lactis grew to the same extent as in the control at 3 days; it remained viable at a low level through 10 days. In APSL cultures, S. lactis growth was inhibited at 3 days but the bacterium survived through 7 days (10 days of mold growth) at reduced numbers. At 3 days there were no appreciable differences in growth of A. parasiticus. At 6 days, in ST and SLAP cultures, growth of the mold was inhibited, while in the APSL culture growth increased over that in the control. At 10 days, growth of mold was somewhat increased over the control in all test conditions. The pH of broth in the A. parasiticus control and APSL culture was 6 at 3 days, dropped to 4.5–4.6 at 6 days and rose to 7 by 10 days. In ST and SLAP cultures, the pH was at 4.1 at 3 days and rose to pH 7 by 10 days. Aflatoxin (B1 plus G1) content was lowest at 3 days and increased at 6 days. Between 6 and 10 days two patterns were observed. In APSL and SLAP cultures, aflatoxin content decreased, while it increased in the ST culture. These patterns occurred when aflatoxin content was expressed on a total or per gram of dried mycelium basis. At 3 days the amounts of aflatoxin B1 and G1 were approximately equal. Between 3–6 days the amount of G1 increased more rapidly than that of B1. Between 6 and 10 days in the ST culture, the amount of G1 increased at a slower rate than that of B1 while in SLAP and APSL cultures, the amount of G1 decreased more rapidly than that of B1. When a different lot of the same medium was used, aflatoxin production was greatly reduced. The pH of broth at all test conditions rose through the incubation period.

Effect of different lots of Mueller-Hinton agar on the interpretation of the gentamicin susceptibility of Pseudomonas aeruginosa.

Population distributions and quality control data for strains of Pseudomonas aeruginosa tested for gentamicin susceptibility on six lots of Mueller-Hinton agar were analyzed. The lots of agar were used in three University of Washington hospitals from April 1975 through October 1977. The analyses indicated that the performance of members of the P. aeruginosa populations in each hospital closely followed the performance of the quality control strain, P. aeruginosa ATCC 27853, when tested on each lot of Mueller-Hinton medium. The variability of zone diameters with the P. aeruginosa populations and the quality control strain indicated that a fixed indeterminate range (13 to 16 mm) of gentamicin susceptibility was not applicable to these organisms as it was with the Enterobacteriaceae. Variability in gentamicin susceptibility results was demonstrated in both minimal inhibitory concentration and disk diffusion tests when eight selected P. aeruginosa strains and the quality control strain were tested on each lot of medium. This variation in susceptibility to gentamicin was not related to the total Ca(2+), Mg(2+), or Zn(2+) content of each lot of medium. The data demonstrated that a moving indeterminate range of gentamicin susceptibility, 3 to 6 mm below the mean zone diameter of the quality control strain, was a suitable criterion for strains tested on a single medium lot. These results illustrate the importance of defining stringent performance standards for media used in the susceptibility testing of P. aeruginosa with gentamicin and other aminoglycoside antibiotics.

Isolation of Acholeplasma laidlawii from commercial, serum-free tissue culture medium and studies on its survival and detection.

This report documents the first isolation of Acholeplasma laidlawii from a commercial lot of serum-free Dulbecco basal medium. Experimental studies demonstrated survival of the organism for at least 1 year depending on the concentration of the contaminating organism as well as pH and temperature of storage of the serum-free medium. A comparison of isolation methods showed that concentration by filtration through 220-nm membrane filters and testing the filters for mycoplasma recovery, especially when using phenol red-diphasic Hayflick medium, was both sensitive and practical for the average laboratory.

Isolation of Acholeplasma laidlawii from Commercial, Serum-Free Tissue Culture Medium and Studies on Its Survival and Detection

This report documents the first isolation of Acholeplasma laidlawii from a commercial lot of serum-free Dulbecco basal medium. Experimental studies demonstrated survival of the organism for at least 1 year depending on the concentration of the contaminating organism as well as pH and temperature of storage of the serum-free medium. A comparison of isolation methods showed that concentration by filtration through 220-nm membrane filters and testing the filters for mycoplasma recovery, especially when using phenol red-diphasic Hayflick medium, was both sensitive and practical for the average laboratory.

The Use of Dehydrated, Coagulated Egg Yolk in the Preparation of a Medium for Culturing Endamoeba histolytica

Endamoeba histolytica has been successfully cultured both on media consisting of slants with liquid overlays and on entirely liquid media. In our laboratory we have been testing the in vitro amoebicidal activity of chemicals on Endamoeba histolytica (University of Chicago strain) grown on E.L.E.S. medium (egg slant with overlay of 0.5% Lilly's liver extract) (Frye and Meleney, 1939) and also the National Institute of Health strain 103, grown on egg slants with modified Stone's Locke's overlay (Anderson, 1945). Due to the work involved in preparation of a medium consisting of a slant with an overlay, and the fact that the slants absorb a certain amount of the test chemical, we realized the need for an entirely liquid medium. After several attempts to culture the University of Chicago strain on St. John's (1932) heart broth medium without obtaining enough actively motile trophozoites for in vitro testing purposes, this medium was discarded. Balamuth and Sandza's (1944) medium, prepared with fresh egg yolks, has produced cultures containing numerous actively motile trophozoites in 48 hours. Difco's Bacto-Coagulated Egg Yolk was selected as a replacement for fresh egg yolks. This product is, as the name implies, dehydrated, coagulated egg yolk, free from egg white, and seems to remain stable for several years when kept in a cool, dry place. The yolks of 500 or more eggs (Difco Co., 1945) are pooled in preparation of one lot of Bacto-Coagulated Egg Yolk, thus standardizing the product. A constant amount can be used in preparation of each lot of medium, tending to maintain reasonably uniform nutritional constituents. In this study an attempt has been made: to determine the least amount of coagulated egg yolk that could be used in preparation of an entirely liquid medium, except for a small amount of solid rice powder; to produce a good growth of actively motile trophozoites in 48-72 hours; to simplify the medium preparation; to insure sterility by autoclaving the final tubed medium; and to obtain a more uniform standard of the constituents by pooling a large number of egg yolks.

Utilization of Certain Sugars and Their Derivatives by Bacteria

In the experiments reported here we have studied the utilization by bacteria of a number of derivatives of the commoner sugars. The sugars used comprised several methyl glycosides, an amino sugar, a sugar acid, a sulphur-containing sugar, and 2 heptoses. The availability of these unusual sugars was compared with that of the common sugars from which they were derived. All sugars were sterilized by filtration and added to suitable culture media to give a concentration of 0.5 to 1.0%. Each lot of medium containing a test sugar was then inoculated with about 25 representative species of the commoner bacteria. Fermentation of the sugar was determined by the usual methods of detecting acid and gas production. It was found that when the hydrogen of the hydroxyl group attached to the number one carbon of the sugar molecule was replaced by a methyl group, the resultant modified sugar was distinctly more resistant to bacterial attack. Thus, of many bacteria which fermented glucose, only a few were able to make use of alpha methyl glucoside. Those able to ferment the methyl glucoside included: Proteus, Bact. friedländeri, Bact. aerogenes, pneumococci, several hemolytic streptococci, and a yeast. Similar comparative tests with mannose and alpha methyl mannoside showed that the latter was not fermented by any of the organisms capable of using mannose. Two methyl pentoses, beta-methyl-1-arabinoside and beta-methyl-d-xyloside, were not used by those organisms capable of fermenting 1-arabinose and d-xylose. Two sugars containing 7 carbon atoms, alpha glucoheptose and alpha glucoheptulose, were not fermented by any of the organisms. Glucosamine was used by most of the cultures which fermented glucose, with the exception of Proteus and 2 yeasts which gave negative results. Gluconic acid was also fermented by most of the glucose-splitting types, with the exception of the streptococci, pneumococci and the yeasts.