Science topic

Bacteriology - Science topic

The study of the structure, growth, function, genetics, and reproduction of bacteria, and BACTERIAL INFECTIONS.
Questions related to Bacteriology
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Is there any gliding bacteria (aerobes & anaerobes) isolated from the gut?
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Bacteria of the phyla Bacteroidetes are abundant in the human gut and oral microbiomes, and many members of this phyla have the ability to navigate surfaces via gliding motility. The Bacteroidetes represent about half of the bacterial population of the human gut microbiome. Kindly check the attached pdf.
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The obvious answer seems to be YES! But a reviewer asked me to find a reference. Anybody knows of any work that compared the EPS of biofilms and colonies?
Or maybe I'm missing something and EPS is a biofilm-only feature that doesn't exist in regular colonies?
If it helps, we're talking about Enterobacteriaceae species like E. coli, K. pneumoniae and P. mirabilis
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I am having bacterial strains in the agar plate. I want to extract these strains and store them in glycerol for long-term use. Is there any stepwise procedure for this process?
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This is the procedure I use for E. coli stocks:
- Take a freshly saturated culture in rich medium (2YT or LB) and spin 2 ml in a 2-ml microfuge tube for 2 min in a microcentrifuge.
- Discard 1 ml of the supernatant and use the remaining 1 ml to resuspend the pellet
- To the concentrated suspension, add 0.5 ml 60% (v/v) sterile glycerol and mix thoroughly by pipetting up and down.
-Transfer the mixture to a cryotube and store at -80 °C
I have kept such viable stocks for decades. When needed, scratch the surface of the frozen stock with a toothipck and use the scratched material to inoculate a fresh culture, without thawing the rest of the stock, which should be returned immediately to the -80°C freezer.
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I want to start my Phd, I am interested in medical bacteriology and molecular biology.
I am interested in infectious diseases, antibiotic resistance, and vaccine development
can you advise me on the most important topics to connect the two fields?
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Thanks a lot, can you suggest to me some specific work ideas.
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Dear academic colleagues!
Sorry for my ignorance in the field of bacteriology!
I need to know if S. mutans and sobrinus are oxidasse (cytochrome) +ve or-ve? Some internet sites reports that S. mutans is -ve, others +ve. Regarding S. sobrinus litle is written.
I believe that a lot of you can easely answer this question.
Thanks!
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Oxidase negative
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I know that we should use API 20 NE for the identification of pseudomonas aeruginosa, but I don't have API 20 NE strips in the lab.
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Hi Richard, Did you do API 20E for Pseudomonas?
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Calling SEM experts and those with SEM in bacteriology. We ran an air dried layer of LB cultured bacteria over the SEM stub. This is like some canalicules being witnessed. can this be bacteria. ON LB agar, we see swarming effect of this bacteria. Please help?
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It's crystals from salt in your buffer. You need to fix your specimen and thoroughly wash it with water to get rid of any salts.
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If I want to transport the sterilized laboratory glassware and bacterial culture in petridshes from one lab to another lab of a short distance then what will be the complete best strategy to avoid the contamination??
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When transporting glassware from one place to another, I do not think that you can avoid contamination 100%, but as much as possible it can be reduced by wrapping these utensils with sterile cellophane and transporting them with the dishes in a sterilized container, knowing that it is better to transfer bacteria through transport media. In general, if you use special selective culture media, you do not need to worry, because such media will prevent the growth of any species other than the one you are investigating.
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I am currently researching the impact of different antimicrobials on the amount of endotoxin released from two different gram-negative bacteria types. I am using nutrient broth as the growth medium and it will end up being transferred into my samples for endotoxin analysis. I am using the ToxinSensor ™ Chromogenic LAL Endotoxin Assay Kit and a spectrophotometer for my analysis. The instructions state not to use a colored sample as it will interfere with the color change when detecting the presence of endotoxins. Is there a way to account for the color of the nutrient broth as the "standard" like I would for the water-blank step or do I need to remove the color completely? How could I remove the color without using something that will damage my sample?
If needed for reference, the instructions for the kit are listed at this link: https://www.genscript.com/product/documents?cat_no=L00350&catalogtype=Document-PROTOCOL
Thanks!
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use a defined medium with trace metals and micronutrients?
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Hi expert out there!
I'm using crystal violet staining to determine gram +ve and -ve bacteria, which is a very traditional method, but at the same time, I noticed that crystal violet also can use for cell viability tests. It seems that the sample that I'm going to use involves cells too, so my question is how can I minimize the chance for the cell to get stained but instead only the bacteria (ie increase the decolorization time will help?)?
Thanks in advance!
Cheers.
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You perform Gram reaction with crystal violet on pure cultures and not mixed cultures. So, please purify your cultures and apply the crystal violet to what you want. The cell culture techniques is a different protocol entirely.
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I'm looking for an alternative for bacteria-bacteria interaction. I'm using transwell to study interaction between 2 bacteria, but I have a lot of contamination problem. I've been looking for dialysis protocol but I don't know if it's a good idea. Any clue?
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I think there are pilli available to study bacteria. In the same manner pillus between two bacteria.
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Hello everyone,
I am looking for the protocol to calculate MIC and MBC by broth microdilution method but I am unable to get a suitable protocol. In papers, they have given the reference of CLSI but when I am opening the reference, sample copy is being displayed which is not having the methodology. Can somebody provide me the detailed protocol for MIC and MBC calculation or share the link of CLSI which is having the complete protocol.
Thank you
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I agreed with Wafaa Eltayeb.
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Hi,
Bacteriology pollutant is commonly observed in river because it is open to the atmosphere and subjected to pollute, despite wastewater effluents in to the river. Chlorine commonly uses for removing bacteria and pathogens contaminants in water, but it has some side effects on human health. Which methods of treatment should be used instead of chlorine without negative impacts?
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I agree with the accurate answer of Dr. Sandhya Jayasekara. She gave almost all the bacterial species that are transported in the water and may pose a public health concern, and I would like to add Aeromonas to them, it is also possible to be transmitted by water and Giardia parasite ... And indeed there is resistance against chlorine in addition to the danger of chlorine because it causes, after its interaction with the organic materials present in the water, from the production of chlorine byproduct, which is the most dangerous of which is trihalomethanes. Indeed, it is possible to treat water with UV radiation, which is an effective method against germs, and it is possible to use ozone then filtering with active biological carbon and then chlorine because here we have implied the purity of water from the remnants of organic materials by filtering and implying that even if a few microorganisms remain after treatment with ozone, it will not reproduce due to filtration of organic matter. Because if we left it unfiltered after the ozone treatment, the remaining micro-organisms might grow rapidly and may cause health problems.
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How can I know the stationary phase of growth of several bacteria?
We are aiming to collect exoproteome of several bacteria. We know that the ideal time to collect exoproteome is during the stationary phase of a particular bacteria. Perhaps we have many bacteria and there is very limited literature on few bacterial stationary phase. Further the information is not available for many bacteria. Could someone suggest us any manual or a paper which describes stationary phase of these bacteria.
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In stationary phase living cells number are equal to dead cells and there are many secondary products
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G. vaginalis grows at 37ºC with 5% CO2 without agitation very very slowly with BHI medium.
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Hi Elvira,
I also observed the change of aspect of Gardnerella vaginalis in the same condition. Is this normal? or how to solve this ? Elvira Marín
Also, my Gardnerella vaginalis cannot grow in the BHI broth at 37 ˚C, 50% CO2.
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Hi,
I want to predict operons on entire bacterial genomes (already annotated). I used to use operon-mapper ( https://academic.oup.com/bioinformatics/article/34/23/4118/5040321), which is great but it has been "under maintenance" for weeks now and I really need one now.
MicrobesOnline doesn't support private genome hosting anymore and I think that the DOOR website is now down.
If you know any other tool, online or not, that would allow the genome-wide prediction of operons in complete, annotated bacterial genomes, that would be of great help to me.
Thanks
Julian
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You can try annotating your genome with tools like PROKKA, PGAP or RAST. And look at the predicted genes and other features
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How long is it possible to store the bacterial culture at 4C?
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It all depends upon what you intend to do with them. If you are just storing them and then plan to streak them out again later, strains should last for months at 4C. However if you want to actually do experiments on the cells you are storing, then probably 24 hours at most before you start having physiological changes.
Note that with E. coli strains if the strain is a recA- strain (like many cloning strains), then their lifespan is MUCH shorter and you will start getting significant cell death in a week or two at 4C.
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There are a few reports about possible genetic control of tissue specificity of Xanthomonas spp:
Bogdanove AJ, Koebnik R, Lu H, Furutani A, Angiuoli SV, Patil PB, Van Sluys MA, Ryan RP, Meyer DF, Han SW, Aparna G. Two new complete genome sequences offer insight into host and tissue specificity of plant pathogenic Xanthomonas spp. Journal of Bacteriology. 2011 Oct 1;193(19):5450-64.
Lu H, Patil P, Van Sluys MA, White FF, Ryan RP, Dow JM, Rabinowicz P, Salzberg SL, Leach JE, Sonti R, Brendel V. Acquisition and evolution of plant pathogenesis–associated gene clusters and candidate determinants of tissue-specificity in Xanthomonas. PLoS One. 2008 Nov 27;3(11):e3828.
Is there any certain gene confirmed as regulator of tissue-specific reaction of xanthomonads?
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It seems to be an answer:
https://advances.sciencemag.org/content/6/46/eabc4516 Repeated gain and loss of a single gene modulates the evolution of vascular plant pathogen lifestyles BY EMILE GLUCK-THALER, AUDE CERUTTI, ALVARO L. PEREZ-QUINTERO, JULES BUTCHACAS, VERÓNICA ROMAN-REYNA, VISHNU NARAYANAN MADHAVAN, DEEPAK SHANTHARAJ, MARCUS V. MERFA, CÉLINE PESCE, ALAIN JAUNEAU, TACA VANCHEVA, JILLIAN M. LANG, CAITILYN ALLEN, VALERIE VERDIER, LIONEL GAGNEVIN, BORIS SZUREK, GREGG T. BECKHAM, LEONARDO DE LA FUENTE, HITENDRA KUMAR PATEL, RAMESH V. SONTI, CLAUDE BRAGARD, JAN E. LEACH, LAURENT D. NOËL, JASON C. SLOT, RALF KOEBNIK, JONATHAN M. JACOBS
SCIENCE ADVANCES13 NOV 2020 : EABC4516
Abstract Vascular plant pathogens travel long distances through host veins, leading to life-threatening, systemic infections. In contrast, nonvascular pathogens remain restricted to infection sites, triggering localized symptom development. The contrasting features of vascular and nonvascular diseases suggest distinct etiologies, but the basis for each remains unclear. Here, we show that the hydrolase CbsA acts as a phenotypic switch between vascular and nonvascular plant pathogenesis. cbsA was enriched in genomes of vascular phytopathogenic bacteria in the family Xanthomonadaceae and absent in most nonvascular species. CbsA expression allowed nonvascular Xanthomonas to cause vascular blight, while cbsA mutagenesis resulted in reduction of vascular or enhanced nonvascular symptom development. Phylogenetic hypothesis testing further revealed that cbsA was lost in multiple nonvascular lineages and more recently gained by some vascular subgroups, suggesting that vascular pathogenesis is ancestral. Our results overall demonstrate how the gain and loss of single loci can facilitate the evolution of complex ecological traits.
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What is the difference between bacteriocins and antibiotics? Can you give me some more examples or usages to distinguish between them?
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Bacteriocins are proteinaceous toxins produced by bacteria to inhibit the growth of similar or closely related bacterial strain(s). ... Antibiotics or antibacterials are a type of antimicrobial used in the treatment and prevention of bacterial infection. They may either kill or inhibit the growth of bacteria. The differences between them are:
1- Bacteriocins are produced on the surface of ribosomes in microbial cells, while antibiotics are primarily secondary metabolites of the cell.
2- Bacteriocin producers are insusceptible to the bactericidal agents, unlike producers of antibiotics.
3- Bacteriocins can attach to the target cell wall anyplace on the surface, as no specific receptors on the target cell wall apparently exist.
4- The mechanism of bacteriocin on target cells is diverse and is associated with the method of pore formation in the outer cell membrane. Bacteriocins bind to cell walls of sensitive microbes, motive ionic imbalances, and produce pores. Inorganic ions leak the target cells through the created pores and thereby killing them. Antibiotics, on the other hand, can inhibit synthesis of the subcellular processes (cell wall synthesis, intracellular protein production, and DNA and RNA replication). Their bactericidal and bacteriostatic mechanisms are diverse and may comprise pore formation, degradation of cellular DNA, disruption via specific cleavage of 16S rRNA, and blockage of peptidoglycan synthesis.
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The efficacy of antibiotic therapy for Helicobacter pylori is highly variable in the world. It depends on bacteriological, environmental and host factors. First- line antibiotic drug-resistance is increasingly seen in some regions of the world. Every time the introduction of new therapeutic schemas are necessary for overcome this problem. According to your personal experience what is the best antibiotic therapy schema in you practice and what is your protocol for confirming eradication? Best regards to everybody
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Dear Prof Diego García-Compeán , given the low virulence of Helicobacter pylori and the high prevalence of its infection worldwide, it might be the time to regard it as a commensal organism, not treat it a pathogen:
The medicines used for the eradication of H. pylori will inevitably kill other commensal organisms in the human microbiome, which might have adverse effect on our health.
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We shall collect biopsies from skin/hoof of animals for bacteriological microbiome analysis. We need suggestions on DNA extraction kit that may be used for this. We prefer to keep the biopsies in a DNA stabilizing reagent (RNAlater), so the kit have to be able to deal with that? If not, we need suggestions on alternatvie storing of biopsies before extraction - as transfering them directly onto ice is not possible.
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Hi Marianne,
I would check out IsoHelix Xtreme DNA isolation kits. The buffer used in the extraction keeps samples shelf stable for a while and might be a good alternative to RNAlater.
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Hello
Trying to make Terrific broth. i make total 100ml of TB.  90ml TB and 10ml TB salts. Autoclave separately and cool down below 50 degrees. and add TB salts . But every  time i add TB salts the entire media gets extremely turbid. even if i add 1 ml of TB salts same thing happens....what could be the reason?? 
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my data comprises of both physical, chemical and bacteriological data
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I think you try using the water quality index
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Is there any other substance, either radioactive or not, that can be used for plasmid curing? And what other methods?
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Apart from intercalating dyes, various antibiotics are also used, such as Coumermycin, Novobiocin, Mitomycin C, Rifampicin, etc. SDS is occasionally used too. You can refer to this classic paper for more insights.
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Is there any medium or visual method to determine the acid production of bacteria? if so, kindly send the literature and references.
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Agree with Rudy Situmeang
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Fe-BABE conjugation can be used to find out the DNA binding region to the enzymes but Fe-BABE conjugation is a tedious process (mostly because of construction of single cysteine derivatives).
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Following
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Pantoea dispersa.
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Probiotics are live microorganisms that are intended to have health benefits when consumed or applied to the body. They can be found in yogurt and other fermented foods, dietary supplements, and beauty products.
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what is your suggestion about an appropriate and trending titles for Medical bacteriology Ph.D. seminar?
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Bacteriocin effects on cancer cells
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I'm working with both facultative anaerobes and obligate aerobes. I was wondering do SIM and/or MIU tests work if the bacteria are aerobic? If not what tests should I do in order to find out whether my bacteria are motile? Hanging drop method doesn't work for me, I've also tried simple wet mound method with some dye to help visualization.
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Brown II, Häse CC. Flagellum-independent surface migration of Vibrio cholerae and Escherichia coli. J Bacteriol. 2001 Jun;183(12):3784-90.
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I propose to determine factors influencing bacteriological and clinical cure in dairy cows with clinical mastitis after treatment with antibiotics. I propose to follow clinically healthy (i.e. without clinical mastitis) lactating cows for the development of new clinical mastitis and also for cure (Bacteriological and clinical cure) of the affected animals after treatment. But there is no any comparison group, i.e. no control group or treatment group (as the antibiotics are also factors to be studied with respective to their type, dosage and others). In addition with this, it is new to be conducted in my country (Ethiopia) which is seems to me difficult to take the previous proportions conducted in developed countries as a proportion estimate in my study due to management or other facilities difference. So my questions are:
1. How do I determine the sample size?
2. Could I use the 50% proportion as proportion estimate in this case?
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Berhe Mengistu your study seems partial epidemiology and partial experimental type. Remember you may want to choose simple random sampling for your epidemiology estimated with help of your local prevalence rate of mastitis by given formulas in Thursfield's book for epidemiology. As for your experimental work, whatever experimental design you may choose, you should have minimum six replicates of each treatment.
Good luck
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This is my first time working with thioglycollate broth and based on everything I've found I am not a 100% sure what this type of growth represents. I can see a growth on the top, then a line of no growth and then dispersed growth almost to the bottom of the tube. Would this be typed as facultative anaerobic bacteria?
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Aerobic and anaerobic bacteria can be identified by growing them in test tubes of thioglycollate broth: 1: Obligate aerobes need oxygen because they cannot ferment or respire anaerobically. They gather at the top of the tube where the oxygen concentration is highest. 2: Obligate anaerobes are poisoned by oxygen, so they gather at the bottom of the tube where the oxygen concentration is lowest. 3: Facultative anaerobes can grow with or without oxygen because they can metabolise energy aerobically or anaerobically. They gather mostly at the top because aerobic respiration generates more ATP than either fermentation or anaerobic respiration. 4: Microaerophiles need oxygen because they cannot ferment or respire anaerobically. However, they are poisoned by high concentrations of oxygen. They gather in the upper part of the test tube but not the very top. 5: Aerotolerant organisms do not require oxygen as they metabolise energy anaerobically. Unlike obligate anaerobes however, they are not poisoned by oxygen. They can be found evenly spread throughout the test tube.
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I have two strains from a single patient. Both have been confirmed as Ps. aeruginosa by PCR. One of them produces a dense brown pigment but the other produces no pigment....has anyone come across this before?
Thanks,
Bruno
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Greetings,
Production of pigment is influenced by culture conditions.
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This is a carbohydrate fermentation test I did with several bacterial species. I used Phenol Red as an indicator and added 1% of different carbohydrate in each tube. This is after 23 hours incubation at 25 degrees Celcius. We incubate at this temperature, as my bacteria grow better at this temp. Some of the samples turned out like this. I don't really know how to interpret these? Can anyone help?
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The picture is more or less typical for bacterial carbohydrate fermentation test
Phenol red is yellow at a pH < 6.8 and red at a pH of > 7.4, therefore if a bacterium ferments a sugar to acid a yellow color will develop.
On picture
A) Formation of acid and gas.
(B) Formation of acid,
(C) inoculated control,
D) alkaline byproducts,
(E) no acid or gas formation.
So you have acid and low alkaline formation in your tubes.
The orange color in the tube, this represents a pH > 6.8 and should not be considered as positive. The yellow tubes are positive.
Hope my explanation is clear.
Good luck  
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Cellulose from acetic acid bacteria through fermentation method, but give me steps about this procedure.
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Probably a little too late, I dont now what you intend to do with this, but I have found that sonication for 30s and centrifugation (33,000 x g) could remove the cell pellet from the Exopolymeric substances. This are really old techniques, and there are more depending on your needs. There are many papers that explain these methods, personaly I liked this one: "Comparison of bacterial extracellular polymer extraction methods by M.J. Brown and J.N. Lester, 1980"
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i'am working on Helicobacter pylori and i'm trying to get a pure colony but it's too difficult!
i wanna know the best sample and conditions for bacteriological isolation of H.pylori.
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You can use selective media for bacteria Isolation, please see in attach file.
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Microbial biofilm is the formation of sticky adhesion layer attached to the surfaces of animate or inanimate objects
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Establishing the relationship of Double J stent Catheters with the episodes of CAUTI and CRBSI and subsequently link its prolonged exposure leading to bacterial translocation as a risk factor for the development of the sepsis.
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Can someone give me a reference where I can find the definition of log reduction of bacteria (due to UV-C irradiation) in terms of disinfection? In other words, how much log reduction is required for disinfection?
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A single log reduction is a 90% reduction of organisms. A two log reduction is a 99% reduction of organisms, followed by a three log reduction (99.9%) etc.
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A group of bacteria (containing several taxa/genera), with ability to degrade a contaminant under specific conditions (pH, temperature), was screened from soil (environmental sample) through sequential transfers and sub-culturing in liquid growth medium. What should I say it, a mixed culture or consortium?
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Microbial consortium: is two or more microbial groups living symbiotically. Consortiums can be endosymbiotic or ectosymbiotic. Symbiosis is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasitic. The organisms may be of the same or of different species.
Symbiosis can be:
obligatory: one or both of the symbionts entirely depend on each other for survival.
facultative (optional): they can generally live independently.
Mixed-culture consists of two or more organisms. Mixed cultures can consist of known species to the exclusion of all others, or they may be composed of mixtures of unknown species. The mixed cultures may be all of one microbial group—all bacteria—or they may consist of a mixture of organisms of fungi and bacteria or fungi and yeasts or other combinations in which the components are quite unrelated. Soil, for example, is a mixed-organism environment with protozoa, bacteria, fungi, and algae growing in various numbers and kinds, depending on the nutrients available, the temperature, and the pH of the soil.
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I want +carry out some susceptibility tests of different bacterial species and was wondering if you could substitute the beef-infusion by meat extract. Or if the two things are the same anyway? What´s the difference between meat-extract and meat-infusion (as the second is an aqueous extract)?
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Thanks for all the tips! This was extremely helpful
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I am really confused!!
Gram-positive or Gram-negative bacteria, which one has a higher surface negative charge? why?
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This seemingly easy to answer question is rather complicated.
Gram-positive and gram-negative bacteria have differences in their membrane structure but it is clear that most of them have a negative charge.
The gram-negative bacteria have a layer of lipopolysaccharide at the external surface followed by a thin layer of peptidoglycan while the cell wall in gram-positive bacteria is mainly composed of a thick layer of peptidoglycan.
It has been shown, using zilver nanoparticles (AgNP), that the AgNPs were more active against gram-negative bacteria and since the electrostatic attraction between positively charged nanoparticles and negatively charged bacterial cells is shown to be an important aspect with regard to the antimicrobial activity of the AgNPs this suggests that Gram-negative bacteria have the highest negatively charged cell wall.
However the MIC against E. coli was found to be the lowest determined concentration among bacterial strains for positively charged AgNPs and therefor seem to suggest that the actual negatively charge vary a lot and depend on the characteristics of the bacterial species.
See for details on all this:
Abbaszadegan, A., Ghahramani, Y., Gholami, A., Hemmateenejad, B., Dorostkar, S., Nabavizadeh, M., & Sharghi, H. (2015). The effect of charge at the surface of silver nanoparticles on antimicrobial activity against gram-positive and gram-negative bacteria: a preliminary study. Journal of Nanomaterials, 16(1), 53.
There is another reason why this question is not easy to answer, and I quote:
“As surface charge and surface potential both vary on a charge-regulated surface, accurate modeling of bacterial interactions with surfaces ultimately requires use of an electrostatic model that accounts for the charge-regulated nature of the cell surface.”
See for details:
Hong, Y., & Brown, D. G. (2008). Electrostatic behavior of the charge-regulated bacterial cell surface. Langmuir, 24(9), 5003-5009.
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I wonder if there are some positive proofs that H pylori is definitely involved in inflammatory skin diseases pathogenesis. Any thoughts?
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Is it possible to have a mixed colony from a pure culture? I'm seeing both positive and negative colours under the microscope.
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Be sure that staining procedure is made accordingly and when taking smear should be from isolated colony to avoid possible sampling from two different colony forming unit adjacent to each other
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I have been growing E. coli host in SM6 medium for fermentation. During the run, I did microscopy and found long filamentous rods, which are Gram negative. I have started searching literature for morphological changes in E. coli due to stress. The antibiotic marker I use is tetracycline.
I'd really appreciate some help here...
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Hi,
You need some biochemical tests.
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i need good topics from general microbiology, virology, bacteriology, mycology, microbial food toxicity, any topics on public health. i would prefer the topics to suit developing countries. thanks in advance
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Let me ask a question - I am assuming you are an undergraduate student, and do you need to do a laboratory based research project or a library written paper as this makes a big difference in what we should suggest. If a lab research project, how much time are you supposed to devote to it, and what type of facilities and equipment do you have to use?
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Benzalkonium chloride (BKC) is Quaternary ammonium compound(disinfectant) and cationic surafctant...used in pharmaceutical industry so we want to test Bacterial endotoxin in (BKC). We did LAL method(limit:2.5 EU/ml, Lysate sensitivity 0.03) but didnt get positive control(No gel formation) and also check by Kinetic chromogenic method but not get the results as BKC have strong disinfectant property.Tween 80 and Lecithin neutralizes this activity so can we use that in LAL method( In dilutions or wherever applicable) and how? 
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OK
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I have tested several media for investigating P-solubilization of Bacillus isolates but none has produced any results yet. I have tried Glucose yeast Agar (GYA) with following incgredients
Glucose (10 g), Yeast extract (2g), Agar (15g). After autoclaving I added the K2HPO4 and CaCl2 (10% solution of each) and poured the media.
I spot inoculated the isolates but didnt see anything even after 7 days.
Then I tested Pikovskaya/s medium with following recipe
Yeast Extract 0.50g
Dextrose 10g
Calcium Phosphate (instead I used Calcium phosphate monobasic) 5.00g
Ammonium Sulphate 0.50g
Potassium Chloride 0.20g
Magnesium Sulphate 0.10g
Manganese Sulphate 0.0001g
Ferrous Sulphate 0.0001g
Agar 15g
Even then I could nt see any halo zone.
I have also used NBRIP-BPB medium (Glucose, 10g; Ca phosphate monobasic, 5g; MgCl2.6H2O, 5g; MgSO4.7H2O, 0.25g; KCl, 0.2g; Ammonium sulphate, 0.1g; Bromophenol blue, 0.025 g; Agar 15g). For NBRIP-BPB medium I adjusted pH to 7 with 10N NaOH but precipitates appeared in the media.
Can anyone let me know where is the problem in my methodology?
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Dear Raheleh
Tri calcium phosphate is always an water insoluble compound under normal pH conditions. That is why you should sterilize it separately as dry powder in the same autoclave when you sterilize the agar or liquid medium. Then just before pouring plates (in case of agar medium) or inoculation of the liquid medium add the powder tri-calcium phosphate in the well cooled medium, shake well to disperse as evenly as possible and proceed.
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For the screening of microplastic biodegradation, i make a culture of bacteria on mineral salt agar(bacteriological agar) with microplastic as the sole carbone source. But in the negatif control (the same medium without carbone source) there is a developpement of some colonies. I can not understand how this bacteria can multiplied without carbone source.
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Hello, no microbial grow without carbon source. But it can be if your bacteria fix carbon dioxide found in the air into reduced carbon, which can be used in all of the various essential metabolic processes.
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Bacteriological examination of water
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Hi,
The MPN method gives good idea about the coliform bacteria and correct numbers of this bacteria.
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Unsuccessful experiment with ruthenium red
To distinguish between EPS-producing (S. thermophilus) and nonproducing (E. coli) cells, M17 agar medium containing 0.08% ruthenium red and ruthenium red milk plates (RRM) (consisted of 0.5% yeast extract, 10% skim milk powder, 1% sucrose, 1.5% agar and 0.08 g L- of ruthenium red) were used. After incubation at 37 ºC for 24 h and 48 h, every strain gave whitish (maybe pale pinkish) colonies. It was unclear.
Stock solution: 0.0877 g of ruthenium red [Ruthenium(III) chloride oxide, Alfa Aesar] in 8.77 ml distilled water was sterilized.
0.8 ml ruthenium red stock was added to 100 ml molten M17 and 100 ml molten RRM agar just prior to pouring it into petri plates. What could be wrong with that?
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I only had success myself using this method when I used Ruthenium Red from Sigma. I used one from Acros Organics originally and even though same formula, weight and CAS# received totally different results. Your agar should be pink to red. The plates should also be protected from light.
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I have read and heard of many studies discussing dangers of raw food diets for cats, but less on the evidence of their impact on the health of cats.
Surely a diet closer to a cats natrual wild diet is preferrable to highly processed and cooked foods, including a high amount of vegetables and grains? If they hunt and eat live prey then why is raw feeding a problem? Is it because it it produced commercially and manufacturing practices can introduce pathogens? Also, would different companies not also have better or worse practices that contribute to a less infected product?
I would love to see more brands tested and more replicates found, and more research done on the presence of pathogenic bacteria in cats as a direct result of their diet, raw or no.
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Hi Jeff
You were asking what lab I work in. I work in a diagnostic lab, in other words, I work in a lab were samples are sent to us from veterinary clinics across the Maritimes and we provide clinical results for the veterinarians to diagnose the issues their patients are having. We do help with running samples for researchers but this is more often for aquatic and Agricultural samples then for small animal research. So in my job I see a lot of samples come through our lab for patients being checked for DCM due to the diets they are on.
So I have no involvement with the pet food industry in my job and I am not influenced by them either.
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Water bacteriology analytical laboratories need to use control organisms (negative - and positive+), to get ISO 17025 accreditation. For this purpose, E coli can be used as total coliform (+) as well as E Coli (+) . As most of the E coli strains are non-pathogenic and can be used safely.
Pseudomonas aeruginosa is used as total coliform (-) and E. coli (-) while, Klebsiella pneumoniae is used for total coliform (+) and E.coli (-)
As Pseudomonas aeruginosa and Klebsiella pneumonia are pathogens, to avoid risk of infections in water analysis laboratories, to use as control organisms, can any expert Microbiologist recommend non-pathogenic strains of these organism or any other alternative non-pathogenic organisms suitable as control bacteria?
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Pseudomonas aerugiunosa is a very poor control for a non-coliform, because it is not even a member of the same family any more (of course, it non-coliform then, but is also very far apart in all other properties form coliforms!). Therefore, you should look for non-pathogenic species within the Enterobacteriaceae, A possible choice may be Shimwellia blattae (formerly Escherichia blattae), which should be non-coliform (no lactose degradation according to Bergey's Manual). For positive controls, there are many non-pathogenic strains of E. coli available (e.g. the original strain K12).
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Hi, I made 40% urea broth medium(Biolife Italiana) to find out the presece of helicobacter pylori in gastric biopsy but this medium responds very slowly for positive biopsy (about 2 hours) while this medium has been tested with pure proteus mirabilis bacteria and give a very fast reaction for a few seconds. My question is why this medium don't work quickly on the biopsy sample and what is needed for a rapid reaction?
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So you use same media used in hospital?
If same sample shows different reaction with your media and hospital,s media, just check with them. Maybe you miss something.
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For the clear plaques, I can understand it's a complete lysis, no bacteria are growing in that aera any more. But how to explain the turbid plaques? Is it the phage lysed some of the bacteria, but the rest got resistant to the phage, which led to a incomplete lysis? And how about the halo plaques?
And why the plaques have certain size, but cannot enlarge limitless?
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Agree with Alejandro Martin's explanations.
As well, worth considering, that lysogen-independent spontaneous mutations in host genes coding for cell surface receptors of phage will occur, contributing to turbid plaque appearance.
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Bergeys manual of systematic bacteriology shows a table in which there is a - sign in front of urease hydrolysis , for bacillus subtilis and bacillus cohnii. I want to ask does that mean these bacteria are non-ureolytic?
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From research report notably the study of accelerated microbial - induced CaCO3 precipitation a defined co-culture of ureolytic Sporosacina and non - ureolytic bacteria Bacillus subtilis . Result obtained indicated that the presence of the non - ureolytic bacterial species , B. subtilis accelerated the MICP process, via the supply of nucleation sites in the form of non - ureolytic bacterial cells. For more details consult www.biogeosciencs.net/11/256/2014/
doi:10.5194/bg-11-2561-2014
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The modern system of classification is based on evolutionary relationships among organisms – that is, on the organisms’ phylogeny. Classification systems based on phylogeny organize species or other groups in ways that reflect our understanding of how they evolved from their common ancestors.
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Some companies claims they have bacterial concentration to the tune of
1 x 10^11. But in our culture technique we could maximum culture 1 x 10^9 which is (1 billion cfu/ml)
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Hello, you can use liquid media for grow culture and precipitate culture by
centrifugation and than you can prepare the culture which quantity you want. You can calculate prepared suspension CFU/ml by decimal dilutions in plates or spectrophotometrically by measuring OD at 600nm after creation relation between OD and CFU at 600nm.
Hope this info will help you.
Good luck !
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Mannitol Salt Agar is the most common technique used to differentiate CoPS from CoNS. But I am curious to know any other techniques or media which can be used to differentiate CoPS from CoNS on an agar plate. Kindly suggest.
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You can not. The only available test for this purpose is coagulase test.
Other tests or agar media are unreliable.
Regards
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Acc to a new classification given by Spatafora et al. (2016) mycorrhiza have been placed in zygomycetes as a sub-phylum- Glomeromycotina (C. Walker & A. Schüßler) Spatafora & Stajich, subphylum and stat. nov...How acceptable is that? Or we still refer to the classification of Glomeromycota as a separate phylum?
A phylum-level phylogenetic classification of zygomycete fungi based on genome-scale data. Mycologia,108(5), 2016, pp. 1028–1046. DOI: 10.3852/16-042#
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Glomerales should be the order including the family Glomeraceae and Claroideoglomeraceae, so, in my opinion, it shouldn't be used instead of Glomeromycota.
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I want to study genetic diversity of Uropathogenic E. coli  .I  DNA extraction methods for E.coli by boiling.but i don't band in elektroforez.
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Dear Zeynab Faraji and everyone with the particular interest,
The RAPD is a very demanding technique, as it requires a lot of precision and the right PCR conditions to be maintained. Firstly, if the RAPD is failing, I would suggest to perform the gradient PCR. I had assessed RAPD with DNA extracted by boiling method and the results were really great, of course, after performing the gradient reaction and finding the best conditions.
In addition, another cheap, repeatable and more reliable method for the genetic diversity of UPEC is ERIC-PCR.
Good luck.
Rūta
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This is primary epithelial cell culture and i notice these tiny black dots attached to cell body. Visible at 40x magnification  and seems like they are vibrating.
It doesnt look like bacterial contamination because I have experienced before and bacteria replicates really quickly overnight and media becomes cloudy. In this case the media stays clear even at day 7 of culture.
Any comment is appreciated.
Thanks
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DAPI stain would confirm whether they are mycoplasma or simply debris. For mycoplasma, you may try adding Plasmocin once and then subculturing in Plasmocin free culture media with antibiotics. This would prevent development of resistance to mycoplasmas. Effective concentration of Plasmocin is very low (around 10-12μg/ml). Confirm the elimination of mycoplasma by RT-PCR.
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What is the basic difference between life and death?
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its pretty simple, life of the reactions of life represent a constant effort to avoid or deter the equilibrium state.
equillibrium conditions represents death
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i am working in a project where we want to separate the magneto-tactic bacteria from the Egyptian aquatic environment and use the magnetosomes of these bacteria after that
what is the technique the isolation of these types of bacteria and without using a differentiation media
if there is good and not expensive protocol to separate it
and in which aquatic environment we can find this types of bacteria
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Hi dear friend , I hope the following article will be useful to you
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There are many types of systems in the bacteriological laboratory are used for identification of bacteria Pseudomonas spp. which one is gratified.
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Both the systems are good for bacterial identification even if the Vitek system is better especially for environmental species; moreover you have to consider the cost that for ViteK is much higher than for the API system.
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Good day!
We're working on a research project involving the identification of Staphylococcus species. We planned to use the coagulase test to help identify the Staphylococcus species, but this is quite pricey. We've encountered the RAPIDEC Staph product by Biomerieux (https://biomerieuxdirect.com/industry/Bacteriology/ID-AST-Manual/ID-AST-API/ID-Manual/Rapidec-Rapidec/RAPIDEC%26reg-STAPH/p/03300) and research partner and I have several questions:
1) We can order product 03300 and this seems more price-effective. Does the RAPIDEC Staph come with everything needed in the test, or do we need to purchase other reagents/kits to be able to use it? If we need to purchase more reagents/kits, this might make it quite expensive as well.
2) Are there online resources on how this test kit is used?
Suggestions of other kits in identifying Staphylococcus (that are hopefully not too expensive) are much appreciated.
Thank you very much.
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There are some different media can help u like manitol salt agar and Baird Parker and Dnase media...all for staph spp
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In a tropical condition, temperature is highly fluctuated and no extreme hot and extreme cold ? If we use bacteriological incubator to grow the bacteria (mesophiles) isolated from natural environment like soil, incubator provides a constant temperature (37C). Basically is it correct or not ? If a biotic organism growing in fluctuated environment, if it is exposed to an in vitro condition with constant temperature, it may affect the growth of bacteria ? But if a bacteria isolated from human instestine, then 37 C is a must, isn't it. If the above statement is Okey, then what is the need of bacteriological incubator are a basic instrument in microbiological lab especially in tropical countries like India or in Asian continents?
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Each type of bacteria has optimum temperature for growth, therefore, incubator is required to give the optimum temperature to the bacteria under study.
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For many decades now many bacteriologists have used yeast extract to successfully culture bacteria. Nowadays, we see multiple examples where yeast extract appears to elicit certain regulation responses and provide with "growth factors" that in absence would prevent cell growth. Despite this, to my knowledge, only a handful of reports describe YE partially but to date, no one seems to take on the task of defining the medium. Thus the question... What is the composition of YE?
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I did just find a partial answer, for anyone interested: "Yeast extract was estimated to be 40% organic carbon, 5% potassium, 0.2% chloride, and 0.13% magnesium based on literature ... it was experimentally determined to be 10% nitrogen, 0.8% ammonia, 1.8% phosphorus, and 1% phosphate and to contribute 0.81 mg COD per mg yeast extract." DOI: 10.1039/C7EW00304H (Paper) Environ. Sci.: Water Res. Technol., 2017, 3, 1120-1131 (Research not done in a connection that would have occurred to me!)
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Maybe somebody can help me and say where is a problem with my methodology. I am fermenting R. leguminosarum in YEM broth. The growth is good, I can see a lot of cells under microscope, but when I am trying to determine the number of cells by plate count technique on the same medium with agar, the colonies do not grow. I tried incubate the plates in 26, 28 and 30 oC but the result was the same. What am I doing wrong?
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Dear Dovilė
follow this paper:
Egeraat AW. Growth requirements of Rhizobium leguminosarum, strain PRE. Plant and Soil. 1977 Aug 1;47(3):699-702.
Best
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Hello! I am currently enrolled in a Bacteriology class this semester. A journal summary has been required in this course wherein it shall focus on the application of bacteria in the field of environment, agriculture, food and industry, fisheries, and medicine. A total of 10 journals shall be summarized in each field. By the end of the semester, three fields shall be chosen and three special projects shall be initiated that are based on the synthesized journals. Thank you!
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Hi! I believe Elsevier Journal Finder and Springer Journal Suggester would help you with this. The links are below:
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What is the best condition to preserve tissue colon samples for one or two months for bacteriological studies (culture and isolation of colorectal bacteria)?
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Thank you
I want to cultivate gut bacteria.
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Hi, I Need this book and references I can`t find it the Bergey’s Manual of Determinative Bacteriology. the method of Brand-Williams et al.,1995. Parekh et al., 2000 using DMSO as a control. And if there any thing would help me stand microbiology methode (books ,website ....) please tell me Thanks so much
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Goodluck
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Morphological culture colonies is very important for preliminary laboratory diagnosis of bacterial genus followed by confirmatory tests.
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Can you provide additional information e.g. Gram stain, colony morphology in other culture medium?
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I have determined MIC's for a certain antimicrobial peptide against M. tuberculosis. My starting CFU/ml is between 1 - 5 x 10^5 cells, using H37Ra. I would like to do various microscopy studies (TEM) on the cells incubated in the presence of the antimicrobial peptide at various time points. Since I have such a low concentration of cells, I struggle to obtain a pellet when centrifuging at 10000 g's for 1 min or 5000 g's for 2 min. I was wondering if anyone could give me any suggestions to obtain a decent pellet to work with? Using centrifuge speeds that won't introduce artifacts or damage my cells. 
Thanks
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Hi Shane,
I know this thread is old but, did you find a good combination to pellet low concentrations of TB cells? I am looking for the same. I would not like cells to break, but I do not care about their viability though.
Bests!
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I am trying to figure out the differences between bacteriological peptone, soya peptone, trypticase peptone, meat digest and peptone from meat.
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Here's the nutrient manual for BD's products. It gives the salt content, nitrogen content, amino acid %, how much of that is free amino acids, etc. Most of these products are made in roughly the same fashion from company to company so even if you're not using BD most of this information should still be mostly correct. Hopefully it will let you make a an educated substitution based on whatever criteria you think would be most important.
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Hi all
Bacterial family use same genes for colonization or every strain use different gene?
Have you information in details?
Can you suggest review articles?
I wanna check a population of bacteria that have been colonized or not.
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At least different from species to species. Furthermore there are fine tunings at the strain level.
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Thanks.
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Enterobacter gives fish eye colonies on EMB.. In some cases E. coli loses the metallic sheen with time when cultures are kept more than 7 days, and the colonies become like fish eyes