A NOTE: POLYVALENT RADIOVACCINE AGAINST SALMONELLA

Salmonella strains exposed to lethal doses of gamma radiation are detoxified but retain their antigenic properties. Using eight Salmonella strains representative of each of the Salmonella serogroups A to G, a polyvalent radiovaccine has been developed which effectively immunizes mice to several Salmonella serotypes.     

Carboxymethyl cellulose (CMC) as an additive for oil reduction in deep-fat fried paneer

The effect of different levels of CMC on the uptake of vegetable oil during the deep-fat frying of paneer was studied by: (i) direct addition of CMC to the milk and (ii) dipping the paneer cubes into solutions of CMC for different time intervals. The fried paneers were evaluated for chemical composition, hardness and sensory characteristics. Method (i) proved to be beneficial in all respects as compared to (ii), as the absorption of water from the suspensions of CMC destroyed the texture of the paneer.     

In vivo demonstration of enhanced probiotic effect of co-immobilized Lactobacillus acidophilus and Bifidobacterium bifidum

The present study was undertaken to evaluate the effectiveness of co-immobilization as an efficient method for delivering high numbers of viable probiotic cultures to the host for an enhanced probiotic effect, using in vivo mice models. The co-immobilized culture of Lactobacillus acidophilus and Bifidobacterium bifidum was fed to eight groups of conventional mice. A greater persistence of probiotic cultures was noticed in the intestinal contents of the groups fed on co-immobilized cells. Further, the supplementation of diet with co-immobilized culture also resulted in maximum lowering of faecal coliforms and the enzymatic activity as compared to the prestudy level.     

Production of Thermonuclease Deficient Mutants from an Enterotoxigenic Thermonuclease Producing Strain of Staphylococcus aureus

A toxigenic strain of Staphylococcus aureus known to produce both thermonuclease and enterotoxin was exposed to ultraviolet radiations. Thermonuclease deficient mutants were recovered on methylgreen-DNA-agar medium. All of twenty thermonuclease deficient mutants lost the capacity to produce coagulase, enterotoxin, and lecithinase. However, these functions were regained upon reversion with visible light (Photoreactivation) thus suggesting a coordinated control mechanism for the synthesis and release of the above metabolites. These characteristics in most of the mutants remained stable for 3 months.     

Low-cost,Concurrent Checking of Pointer and Array Accesses in C Programs

Illegal pointer and array accesses are a major cause of failure for C programs. We present a technique called ‘guarding’ to catch illegal array and pointer accesses. Our implementation of guarding for C programs works as a source-to-source translator. Auxiliary objects called guards are added to a user program to monitor pointer and array accesses at run time. Guards maintain attributes to catch out of bounds array accesses and accesses to deallocated memory. Our system has found a number of previously unreported errors in widely-used Unix utilities and SPEC92 benchmarks. Many commonly used programs have bugs which may not always manifest themselves as a program crash, but may instead produce a subtly wrong answer. These programs are not routinely checked for run-time errors because the increase in execution time due to run-time checking can be very high. We present two techniques to handle the high cost of run-time checking of pointer and array accesses in C programs: ‘customization’ and ‘shadow processing’. Customization works by decoupling run-time checking from original computation. A user program is customized for guarding by throwing away computation not relevant for guarding. We have explored using program slicing for customization. Customization can cut the overhead of guarding by up to half. Shadow processing uses idle processors in multiprocessor workstations to perform run-time checking in the background. A user program is instrumented to obtain a ‘main process’ and a ‘shadow process’. The main process performs computations from the orignal program, occasionally communicating a few key values to the shadow process. The shadow process follows the main process, checking pointer and array accesses. The overhead to the main process which the user sees is very low – almost always less than 10%. © 1997 by John Wiley & Sons, Ltd.     

Factors Affecting Enterotoxin Production by Thermonuclease Positive Streptococcus faecium IF-100 Isolated from an Infant Food

Among the different media tested for optimal production of enterotoxin by Streptococcus faecium IF-100, trypticase soy broth was the best for maximal enterotixin production by Streptococcus faecium IF-100 at 37°C after 8 hr incubation in agitated cultures. The pH optimum was 8.0. Although addition of 1% casamino acid enhanced enterotoxin production, yeast extract did not affect enterotoxin production appreciably. Dextrose, at 0.5%, was inhibitory towards enterotoxin production. Production of enterotoxin was also inhibited by addition of acridine orange, suggesting possible involvement of some extra chromsomal factor in the production of this metabolite in S. faecium IF-100. A supplemented medium for maximum enterotoxin production is described.     

Heat Resistance and Other Characteristics of Deoxyribonuclease Positive Enterococci Isolated from Milk and Milk Products

Out of 224 deoxyribonulcease (DNase) positive enterococci recovered from dairy products, 21.9% survived pasteurization. Among the latter, 26 exhibited thermonuclease activity and 14 were hemolytic. Enterotoxigenic activity in rabbit ileal loops was exhibited by 13 strains, whereas 14 strains were pathogenic to mice. Resistance to penicillin and streptomycin was shown by 5 1 and 47 strains, respectively. There appears to be a positive relationship between heat resistance, thermonuclease activity, enterocin production by these organisms and their resistance to penicillin and streptomycin. As many as 37 heat resistant strains were recovered from samples of nonfat dry cow's milk, infant foods and from sweetened condensed milk. The predominant heat resistant strains were identified as Streptococcus faecalis var. faecalis., Streptococcus faecium and Streptococcus faecalis var zymogenes.     

Effect of Moist Ammonia on the Strength of Polymer-Coated Optical Fibers

The tensile strength of polymer-coated fused silica optical fibers aged in a moist ammonia environment at 23°C was drastically reduced compared to that of fibers aged under ammonia-free high-humidity conditions. However, most of the strength lost on aging in ammonia was recoverable by ambient desorption of the ammonia, in analogy to the strength recovery which occurs when fibers aged in water are dried.     

Identification of β-SiC surrounded by relatable surrounding diamond medium using weak Raman surface phonons

It is difficult to detect β-SiC using micro-Raman scattering, if it is surrounded by carbon medium. Here, β-SiC is identified in the presence of a relatable surrounding diamond medium using subtle, but discernible Raman surface phonons. In this study, diamond/β-SiC nanocomposite thin film system is considered in which nanosized β-SiC crystallites are surrounded by a relatable nanodiamond medium that leads to the appearance of a weak Raman surface phonon band at about 855 cm^???1. Change in the nature of the surrounding material structure and its volume content when relatable, will affect the resultant Raman response of β-SiC phase as seen in the present case of diamond/β-SiC nanocomposite thin films.     

Factors Affecting Amine Production by a Selected Strain of Lactobacillus bulgaricus

Lactobacillus bulgaricus-52 showed maximum growth and amine production in MRS broth in 24 hr at 37°C. The optimum pH for the production of histamine, tyramine, and tryptamine by L. bulgaricus-52 was 5.0. Highest yields of the different amines were obtained in the absence of NaCI in the growth medium. A concentration of even 0.5% NaCI had a slight inhibitory affect on the synthesis of amines. A similar trend was observed in terms of amine production by L bulgaricus-52 in milk samples held at 37°C for different time intervals.