Enhanced β-lactam antibiotic production by coimmobilization of fungus and alga

Summary It was determined thatCephalosporium acremonium, an oxygenconsuming fungus, had a symbiotic relationship withChlorella pyrenoidosa, an oxygen-generating alga. The fungus and the alga were coimmobilized by entrapment in calcium alginate beads. The production rate of -lactam antibiotics was evaluated at various ratios of the fungus and the alga cells in the free and immobilized states. When the ratio of fungus to alga was one to eight in free mixed culture, the production rate of -lactam antibiotics was 240% of the rate in the presence of fungus alone in the free state. In coimmobilized cell system, the increased amount was 370% in comparison with immobilized fungus alone.     

Modeling the effect of oxygen mass transfer on β-lactam antibiotic production by immobilizedCephalosporium acremonium

Summary The oxygen effect on the production of -lactam antibiotics was investigated whenCephalosporium acremonium was immobilized in calcium alginate. Theoretical effectiveness factors were calculated and compared with experimental ones. The approximate expressions of effectiveness factors reported in the literature were compared with the numerically obtained solutions to provide the best approximated expression for immobilizedC. acremonium cells. Yamane's approximate expression of effectiveness factor was best fit with the solutions numerically obtained in this investigation.     

Inhibition of erythroid progenitor growth is mediated by cytotoxic lymphocytes and not by natural killer cells or IFN-gamma

Alloantigen primed T cells (PTC) were recovered from MLR at day 6 and 12, then added to cultures of erythroid progenitors, erythroid burst-forming units, BFU-E. The PBMC source of BFU-E was prepared either to retain or deplete APC by treatment with appropriate mAb and C. BFU-E grown in cocultures were counted at day 14 and replicate cultures assayed for IFN-gamma production on days 1 to 7. Analysis of MLR cells indicated that large, rapidly cycling cells recovered from MLR at day 6 have significant NK activity, whereas CTL activity is minimal, and production of IFN-gamma requires reexposure to APC. The smaller, noncycling cells recovered from MLR at day 12 have comparable NK activity, also require reexposure to APC for IFN-gamma production, but in addition have significant CTL activity. The addition of day 12 MLR cells to BFU-E cultures results in MHC restricted inhibition of BFU-E growth, suggesting that the CTL activity and not the NK activity contained within this population of cells is responsible for BFU-E inhibition. Studies using enriched population of BFU-E indicated that appropriate APC are needed to trigger both IFN-gamma production and BFU-E inhibition by the PTC. By using various APC-BFU-E combinations it was determined that after reexposure of PTC to appropriate APC, the inhibition of BFU-E was still target-specific indicating a direct effect between the PTC and BFU-E.     

Conversion of human lymphocytes to antitumor immune reactivity by xenogeneic and allogeneic imune RNA detected by leukocyte-adherence inhibition tests

Summary Using leukocyte adherence inhibition (LAI) tests, we studied the activity of xenogeneic immune RNA (I-RNA) extracted from the spleen and lymph nodes of sheep after immunization with human breast carcinoma tissue or keyhole limpet hemocyanin (KLH) in inducing lymphocytes from normal healthy donors to mediate immune responses in vitro. Mononuclear cells isolated from venous blood of normal donors, depleted of monocytes and, in some experiments, separated into T cells and non-T cells, were incubated with and without anti-breast carcinoma I-RNA or anti-KLH I-RNA for 20 min at 37° C. Then, lymphocyte adherence was determined by a Coulter counter method in the presence of 3 M KCl extracts of breast carcinoma tissues, control tissue, or KLH. Following incubation with anti-breast carcinoma I-RNA, the adherence of lymphocytes from normal donors was found to be inhibited only in the presence of breast carcinoma extracts. Following incubation with anti-KLH I-RNA, lymphocyte adherence was inhibited only in the presence of KLH. The principal effector cells involved appeared to be T lymphocytes. I-RNA treatment with RNase, but not with DNase or pronase, completely abrogated the LAI responses. In a blind study utilizing coded samples of xenogeneic and allogeneic I-RNA of unknown origin, samples containing activity against breast cancer extracts were identified correctly by LAI. Abbreviations used: I-RNA, immune RNA; LAI, leukocyte adherence inhibition; KLH, Keyhole limpet hemocyanin; PBS, phosphate buffered saline; RNase, ribonuclease; DNase, deoxyribonuclease     

Seed biopriming with novel strain of Trichoderma harzianum for the control of toxigenic Fusarium verticillioides and fumonisins in maize

Fusarium verticillioides is one of the most important fungal pathogens in maize causing both pre- and post-harvest losses and also capable of producing Fumonisins. In the present study attempts have been made for screening potential T. harzianum from native rhizosphere and to study its effect on Fusarium ear rot disease, fumonisin accumulation in different maize cultivars grown in India. Eight isolates of T. harzianum were isolated and T. harzianum isolate Th-8 exhibited better antifungal activity than carbendizim. Th-8 was formulated in different solid substrates like wheat bran, paddy husk, talcum powder and cornstarch. Maize seeds of kanchan (moderately resistant), pioneer (resistant) and sweet corn (susceptible) were selected for laboratory and field studies and these seeds were treated with a conidial suspension of T. harzianum at the rate of 1 × 10⁸ spore/ml and formulation at the rate of 10 g/kg. Treated seeds were subjected to evaluate F. verticillioides incidence, seed germination, seedling vigour and field emergence, yield, thousand seed weight and fumonisin production. It was found that the pure culture of T. harzianum was more effective in reducing the F. verticillioides and fumonisin incidence followed by Talc formulation than the carbendizim treated and untreated control. Formulations of T. harzianum were effective at reducing the F. verticillioides and Fumonisin infection and also increasing the seed germination, vigour index, field emergence, yield, and thousand seed weight in comparison with the control.     

Economic and Health Impacts Associated with a Salmonella Typhimurium Drinking Water Outbreak?Alamosa,CO, 2008

In 2008, a large Salmonella outbreak caused by contamination of the municipal drinking water supply occurred in Alamosa, Colorado. The objectives of this assessment were to determine the full economic costs associated with the outbreak and the long-term health impacts on the community of Alamosa. We conducted a postal survey of City of Alamosa (2008 population: 8,746) households and businesses, and conducted in-depth interviews with local, state, and nongovernmental agencies, and City of Alamosa healthcare facilities and schools to assess the economic and long-term health impacts of the outbreak. Twenty-one percent of household survey respondents (n = 369/1,732) reported diarrheal illness during the outbreak. Of those, 29% (n = 108) reported experiencing potential long-term health consequences. Most households (n = 699/771, 91%) reported municipal water as their main drinking water source at home before the outbreak; afterwards, only 30% (n = 233) drank unfiltered municipal tap water. The outbreak’s estimated total cost to residents and businesses of Alamosa using a Monte Carlo simulation model (10,000 iterations) was approximately $1.5 million dollars (range: $196,677–$6,002,879), and rose to $2.6 million dollars (range: $1,123,471–$7,792,973) with the inclusion of outbreak response costs to local, state and nongovernmental agencies and City of Alamosa healthcare facilities and schools. This investigation documents the significant economic and health impacts associated with waterborne disease outbreaks and highlights the potential for loss of trust in public water systems following such outbreaks.     

Regulation of nucleoside diphosphate kinase and an alternative kinase in Escherichia coli: role of the sspA and rnk genes in nucleoside triphosphate formation

We have previously reported that two genes cloned from a cosmid library of Escherichia coli can restore mucoidy to an algR2 mutant of Pseudomonas aeruginosa . AlgR2 is a protein involved in the regulation of nucleoside diphosphate kinase (Ndk) as well as alginate synthesis in P. aeruginosa . One of the E. coli genes, rnk , encodes a 14.9 kDa protein with no homology to any other proteins. The other gene, sspA , encodes the stringent starvation protein, a regulatory protein involved in stationary-phase regulation and the stringent response of E. coli . While both rnk and sspA restored alginate production to the P. aeruginosa algR2 mutant, only rnk restored Ndk activity to the mutant. In this report, we have examined the effect of mutations in rnk and sspA on the levels of Ndk in E. coli . We find that a mutation in rnk drastically reduces the level of Ndk in E. coli . A mutation in sspA , however, affects the level of another nucleoside diphosphate kinase distinct from Ndk. The proteins can be easily distinguished from each other by their different affinities for nucleoside diphosphates (NDPs) and also by the differential effect of anti-Ndk antibodies on the reactions they catalyse. The ability of either of these two proteins to restore alginate synthesis in the algR2 mutant of P. aeruginosa demonstrates the importance of nucleoside triphosphate synthesis and energy metabolism for alginate synthesis. Additionally, a role for the stringent starvation protein (SspA) in the modulation of nucleoside triphosphate (NTP) levels in E. coli is also suggested from these experiments.