Changes in Cellular Fatty Acid Composition of Cephalosporium acremonium during Cephalosporin C Production

Cephalosporium acremonium was cultivated in fermentation medium containing sucrose or methyl oleate as a carbon source for cephalosporin C production. The level of antibiotic production was 48 g of cephalosporin C per liter under optimum conditions when methyl oleate was used. The C_18:1 (oleic acid) methyl ester appeared to be utilized faster than the C_18:2 (linoleic acid) methyl ester in fermentation broth. Physiological characteristics of C. acremonium were investigated by determining the fatty acid composition of the total cellular free lipid. Significant changes in cellular fatty acid composition occurred during inoculum cultivation and fermentation. The percentage of C_18:1 increased from 19.1 to 38.5%, but the percentage of C_18:2 decreased from 56.7 to 36.1%, and there was an increase in pH during inoculum cultivation. The cellular fatty acid composition of C. acremonium grown in fermentation medium containing methyl oleate (methyl oleate medium) was significantly different from that in fermentation medium containing sucrose (sucrose medium). The major fatty acids detected were C_16:0 (palmitic acid), C_18:1, and C_18:2. In methyl oleate medium, the ratio of C_18:1 to C_18:2 increased from 0.34 to 1.37, while the cell morphology changed from hyphae to arthrospores and conidia. In contrast, in sucrose medium, the ratio of C_18:1 to C_18:2 decreased from 0.70 to 0.43, and most of the cells remained hyphal at the end of fermentation. We observed that hyphae contained a higher proportion of C_18:2 but arthrospores and conidia contained a higher proportion of C_18:1.     

Quantitative cell lysis of indigenous microorganisms and rapid extraction of microbial DNA from sediment.

This study reports improvements in two of the key steps, lysis of indigenous cells and DNA purification, required for achieving a rapid nonselective protocol for extracting nucleic acids directly from sodium dodecyl sulfate (SDS)-treated sediment rich in organic matter. Incorporation of bead-mill homogenization into the DNA extraction procedure doubled the densitometrically determined DNA yield (11.8 micrograms of DNA.g [dry weight] of sediment-1) relative to incorporation of three cycles of freezing and thawing (5.2 micrograms of DNA.g [dry weight] of sediment-1). The improved DNA extraction efficiency was attributed to increased cell lysis, measured by viable counts of sediment microorganisms which showed that 2 and 8%, respectively, survived the bead-mill homogenization and freeze-thaw procedures. Corresponding measurements of suspensions of viable Bacillus endospores demonstrated that 2 and 94% of the initial number survived. Conventional, laser scanning epifluorescence phase-contrast, and differential interference-contrast microscopy revealed that small coccoid bacterial cells (1.2 to 0.3 micron long) were left intact after combined SDS and bead-mill homogenization of sediment samples. Estimates of the residual fraction of the fluorescently stained cell numbers indicated that 6% (2.2 x 10(8) cells.g [dry weight] of sediment-1) of the original population (3.8 x 10(9) cells.g [dry weight] of sediment-1) remained after treatment with SDS and bead-mill homogenization. Thus, lysis of total cells was less efficient than that of cells which could be cultured. The extracted DNA was used to successfully amplify nahR, the regulatory gene for naphthalene catabolism in Pseudomonas putida G7, by PCR.(ABSTRACT TRUNCATED AT 250 WORDS)     

Keraladiaptomus rangareddyi a new genus and new species of Diaptominae (Copepoda,Calanoida, Diaptomidae) from a temporary pond in Mattam,Kerala State,India

Calanoid copepods, belonging to the new genus and species Keraladiaptomus rangareddyi, were collected from temporary ponds in Kerala State, India. The new genus belongs to the family Diaptomidae, subfamily Diaptominae. It is described in detail and its affinity to the related genera, Arctodiaptomus Kiefer, 1932 and Eodiaptomus Kiefer, 1932, discussed.     

IR and Raman spectroscopic studies of the interaction of trehalose with hen egg white lysozyme

Infrared and Fourier transform Raman spectra are reported for dried mixtures of trehalose and lysozyme. The Raman spectra show effects on the protein amide I band and some sugar bands that are not present when the components are dried separately. Comparison of ir spectra with those published previously show significant differences. It is concluded that these arise because of differences in the extent of drying of the moisture, and that, contrary to some claims, vibrational spectroscopy does not so far show any clear evidence of specific trehalose/protein interactions and that results may be interpreted in terms of entrapment of water within the mixture. © 1994 John Wiley & Sons, Inc.     

Validation of the cumulative or replicate NAA method for the determination of trace elements in biological materials

Biological Trace Element Research - To make the best use of time and facilities, a neutron activation system, fully automatic, including spectrum and data processing, to be used with short-lived...     

Vertical thin-layer photoreactor for controlled cultivation of cyanobacteria

Nostoc sp. was cultivated in an air-lift reactor with continuous recirculation of the head gas phase that aerated and agitated the cyanobacterial suspension at regulated flow rates. The supply of inorganic carbon for growth was coupled with pH control, in the range of 7.7 to 8.1, by intermittent sparging of CO₂-head gas mixtures. The formation of irregular bubbles with swirling motion at the photostage of the reactor promoted efficient CO₂ transference in dense populations of Nostoc sp. (1.1 g/l) when bubbling at flow rates of 10 l/min. Biomass productivity was almost six-fold higher in the photoreactor (16.4 mg/l.h) than in a conventional system (2.8 mg/l.h). The exponential growth phase of cultures in the photoreactor amounted to 60% of the total growth period.The authors are with the Laboratorio de Alimentos, Area Microbiologia, Facultad de Quimica Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis, Argentina     

Expression of a maize proteinase inhibitor gene is induced in response to wounding and fungal infection: systemic wound-response of a monocot gene

The isolation and characterization of cDNA and genomic clones encoding a proteinase inhibitor protein (MPI) in maize is reported. Accumulation of the MPI mRNA is induced in response to fungal infection in germinating maize embryos. The expression pattern of the MPI gene, in healthy and fungal infected maize tissues, was examined and compared with the expression pattern of a gene that codes for a pathogenesis-related protein (the PRms protein) from maize. These two genes are induced by fungal infection, however different signals trigger their activation. Accumulation of the proteinase inhibitor mRNA is more a consequence of the wound produced by the penetration and colonization of the host tissues by the pathogen, than the result of a direct molecular recognition of the pathogen by the plant, as is the case for the induction of the PRms gene. Wounding, or treatment with abscisic acid or methyl jasmonate, stimulate MPI mRNA accumulation, but not PRms mRNA accumulation. Local and systemic induction of the MPI gene expression in response to wounding occurs in maize plants. To the authors' knowledge, this is the first example of a gene from a monocotyledonous species that clearly shows a systemic wound response. The possible functional implications for the existence of different signal transduction pathways that simultaneously activate a battery of defense mechanisms against potential pathogens are discussed.     

A pre-formed Pyrogenic Factor Released by Lipopolysaccharide Stimulated Macrophages

The aim of this study was to investigate the pyrogenic activity of factor(s) released by rat peritoneal macrophages following a brief stimulation with LPS. The effect of this factor on the number of circulating leukocytes and serum Fe, Cu and Zn levels, was also evaluated. The possibility that the content of interleukin (IL)-1beta, IL-6 and tumour necrosis factor (TNF) in the supernatant could explain the observations was investigated. Supernatant produced over a period of 1 h by peritoneal macrophages, following a 30 min incubation with LPS at 37 degrees C, was ultrafiltered through a 10 000 MW cut-off Amicon membrane, sterilized, and concentrated 2.5, 5, 10 and 20 times. The intravenous (i.v.) injection of this supernatant induced a concentration-dependent fever in rats with a maximal response at 2 h. The pyrogenic activity was produced by macrophages elicited with thioglycollate and by resident cells. The supernatants also induced neutrophilia and reduction in Fe and Zn 6 h after the injection. Absence of activity in boiled supernatants, or supernatants from macrophages incubated at 4 degrees C with LPS, indicates that LPS was not responsible for the activity. In vitro treatment with indomethacin (Indo), dexamethasone (Dex), or cycloheximide (Chx) did not modify the release of pyrogenic activity into the supernatant or its effects on the reduction in serum metal levels. Although Chx abolished the production of mediator(s) inducing neutrophilia, and Dex reduced the induction of IL-1beta, TNF and IL-6, injection of the highest concentration of these cytokines detected in the supernatants did not induce fever. In vivo treatment with Dex, but not Indo, abolished the fever induced by the supernatant. These results suggest that macrophages contain pre-formed pyrogenic mediator(s), not related to IL-1beta, IL-6 or TNF, that acts indirectly and independently of prostaglandtn. It also seems likely that the pyrogenic activity is related to the factor responsible for the reduction of serum Fe and Zn levels, but not the neutrophilia.     

Prevalence of Colonization Factor Antigens (CFAs) and Adherence to HeLa Cells in Enterotoxigenic Escherichia coli Isolated from Feces of Children in São Paulo

Fifty-eight enterotoxigenic Escherichia coli (ETEC) strains, isolated from children with and without diarrhea in Sao Paulo, were examined for the presence of colonization factor antigens (CFAs) and their ability to adhere to HeLa cells. Antisera to CFA/I, the coli surface (CS) antigens CS1CS3, CS2CS3, and CS2 of CFA/II, CFA/III, and CS5CS6 and CS6 of CFA/IV were used. CFAs were identified in 43% of the ETEC strains: 40% of the strains with CFAs harbored CFA/I, 24% carried CFA/II (CS1CS3), 24% carried CFA/IV (CS6), and 12% carried CFA/IV (CS5CS6). CFAs occurred mainly among ETEC strains producing only heat-stable (ST-I) enterotoxin and in strains also producing heat-labile toxin (LT-I). No ETEC strains tested expressed CFA/III. A marked change in serotypes of ST-I-producing strains was found in Sao Paulo between 1979 and 1990. Adherence to HeLa cells was detected in 14% of the ETEC strains. All of them had a diffuse adherence pattern and produced only ST-I, and 88% carried CS6 antigen.