scholarly journals Grazing and utilization of chroococcoid cyanobacteria and heterotrophic bacteria by protozoa in laboratory cultures and a coastal plankton community

1991 ◽  
Vol 76 ◽  
pp. 205-217 ◽  
Author(s):  
DA Caron ◽  
EL Lim ◽  
G Miceli ◽  
JB Waterbury ◽  
FW Valois
Author(s):  
M. R. Edwards ◽  
J. D. Mainwaring

Although the general ultrastructure of Cyanidium caldarium, an acidophilic, thermophilic alga of questionable taxonomic rank, has been extensively studied (see review of literature in reference 1), some peculiar ultrastructural features of the chloroplast of this alga have not been noted by other investigators.Cells were collected and prepared for thin sections at the Yellowstone National Park and were also grown in laboratory cultures (45-52°C; pH 2-5). Fixation (glutaraldehyde-osmium), dehydration (ethanol), and embedding (Epon 812) were accomplished by standard methods. Replicas of frozenfracture d- etched cells were obtained in a Balzers apparatus. In addition, cells were examined after disruption in a French Press.


Author(s):  
Xiaorong Zhu ◽  
Richard McVeigh ◽  
Bijan K. Ghosh

A mutant of Bacillus licheniformis 749/C, NM 105 exhibits some notable properties, e.g., arrest of alkaline phosphatase secretion and overexpression and hypersecretion of RS protein. Although RS is known to be widely distributed in many microbes, it is rarely found, with a few exceptions, in laboratory cultures of microorganisms. RS protein is a structural protein and has the unusual properties to form aggregate. This characteristic may have been responsible for the self assembly of RS into regular tetragonal structures. Another uncommon characteristic of RS is that enhanced synthesis and secretion which occurs when the cells cease to grow. Assembled RS protein with a tetragonal structure is not seen inside cells at any stage of cell growth including cells in the stationary phase of growth. Gel electrophoresis of the culture supernatant shows a very large amount of RS protein in the stationary culture of the B. licheniformis. It seems, Therefore, that the RS protein is cotranslationally secreted and self assembled on the envelope surface.


2020 ◽  
Vol 82 (6) ◽  
pp. 54-63
Author(s):  
M.Ya. Vortman ◽  
◽  
Yu.B. Pysmenna ◽  
A.I. Chuenko ◽  
D.R. Abdulina ◽  
...  

Biocides are widely used in medicine and various industries to protect against a number of harmful microorganisms. Organic quaternary ammonium and guanidine-containing compounds, the biological action of which is based on membrane-toxic properties, are used as bactericidal preparations. The aim of this work was to study the bactericidal and fungicidal activities of the synthesized oligomeric alkylsubstituted guanidinium bromides with different radicals -C3H7, -C7H15, -C10H21, against different isolates of heterotrophic bacteria and microscopic fungi. Methods. The synthesis of alkyl-substituted guanidiniumcontaining oligomers was performed in two stages. In the first stage, alkyl-substituted guanidine was obtained by the reaction of guanidine, previously converted by alkali from the salt form to the base form by the base and alkyl bromides (Alk=-C3H7 (propyl), -C7H15 (heptyl), -C10H21 (decyl)) in methanol at a temperature of 50°C and a molar ratio of 1:1. The second carried out the reaction between aromatic oligoepoxide DER-331 and alkyl-substituted guanidine in methanol at a temperature of 50°C for 2–3 hours and a molar ratio of 1:2. Bacteria were grown on meat-peptone agar for 48 hours at a temperature of 28±2°С. Test cultures of micromycetes were cultured on agar beer wort (6°B), incubated for 14 days in a thermostat at a temperature of 28±2°C. Antimicrobial activity of newly synthesized alkyl-substituted guanidinium-containing oligomers was determined by standard disco-diffusion method (method of disks on agar) and fungicidal activity was determined by the method of holes in agar. Results. Oligomeric alkylsubstituted guanidinium bromides with different radicals composed -C3H7, -C7H15, -C10H21- synthesized by the reaction of guanidine alkyl bromides with aromatic oligoepoxydes. It was found that alkyl-substituted guanidinium-containing oligomers at a concentration of 1–3% inhibited the growth of Escherichia coli 475, Pseudomonas aeruginosa 465, Klebsiella pneumonia 479, Pseudomonas pseudoalcaligenes 109, Staphylococcus aureus 451, E. faecalis 422, Rhodococcus erythropolis 102, Bacillus subtilis 138 and most of the studied micromycetes – Aureobasidium pullulans F-41430, Paecilomyces variotii F-41432, Penicillium funiculosum F-41435, Penicillium ochrochloron F-41431, Scopulariopsis brevicaulis F-41434, Trichoderma viride F-41437, Candida albicans F-41441, Aspergillus flavus F-41442, Aspergillus niger F-41448, Penicillium sp. F-41447. Conclusions. Antimicrobial and fungicidal properties significantly depend on the length of the alkyl radical, with increasing of its length the diameter of the zone of bacterial and micromycetes growth retardation increases.10.15407/microbiolj82.06.054


2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Lies Indah Sutiknowati

The objective of this research was to evaluate waters quality in Pari island waters for aquaculture purpose based on bacteriological information conducted in Mei and September 2011. Microbiological parameters analyzed were total density of bacteria for coliforms, E.coli, pathogenic, heterotrophic, halotoleran, phosphate-nitrate-ammonia breaker, and total cells. Method to analyze coliform bacteria was filtration, identification of pathogenic bacteria using biochemical test, density analises for heterotrophic bacteria, analises for phosphate-nitrate-ammonia breaker bacteria using pour plate, and total cell using Acridine Orange Epifluorescence Microscopy. Results showed that the abundance of total coliform cell was about 1000-7000 colony forming unit (cfu)/100 ml. The abundance of heterotrophic, halotolerant, phosphate-nitrate-ammonia bacteria in seawater was (3.6-4.3)x105 cfu/ml, (1.1-1.3)x105 cfu/ml, (0.5-3.44)x103cfu/ml; and (3.6-6.7)x105 cfu/ml, (1.6-2.7)x105 cfu/ml, (0.6-5.22)x103 cfu/ml in sediment, respectively. The total cell of bacteria was (0.05-2.1)x107cells/ml. The dog-conch (Strombus turturella) and blood-clamps (Anadara granosa) can survive in Pari Island and there was a significant increase in sea grass litter with growth average of 0.67 mm/day and 0.90 mm/day. During snails and clamps growth, there were found several genus of pathogenic bacteria such as Salmonella, Vibrio, Aeromonas, Pseudomonas, Citrobacter, Proteus, Shigella, Hafnia, and Yersinia. The results showed that Pari island waters was suitable for developing shellfish aquaculture dog conch and blood clamps. Keywords: bacteria, parameter, shellfish, aquaculture.


2012 ◽  
Vol 36 (10) ◽  
pp. 1572 ◽  
Author(s):  
Luo-qin FU ◽  
Jian-dong SUN ◽  
Bin DENG ◽  
Quan LIANG ◽  
Xiao-ping ZHANG ◽  
...  

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