Microbiology Pills: Prokaryotes versus Eukaryotes

Chronic kidney disease alters intestinal microbial flora

The population of microbes (microbiome) in the intestine is a symbiotic ecosystem conferring trophic and protective functions. Since the biochemical environment shapes the structure and function of the microbiome, authors of this research work have tested whether uremia and/or dietary and pharmacologic interventions in chronic kidney disease alters the microbiome.

Basic techniques in Microbiology: Microscope Cleaning

Basic techniques in Microbiology: Using a Bunsen Burner

Basic techniques in Microbiology: The Lactophenol Cotton Blue Technique

Basic techniques in Microbiology: Aseptic Technique

Basic techniques in Microbiology: How to do a Catalase Test

Basic techniques in Microbiology: Broth Innoculation

Basic techniques in Microbiology: The Streak-Plate Method

Basic techniques in Microbiology: How to do an oxidase test

PKMiner: a database for exploring type II polyketide synthases

Bacterial aromatic polyketides are a pharmacologically important group of natural products synthesized by type II polyketide synthases (type II PKSs) in actinobacteria. Isolation of novel aromatic polyketides from microbial sources is currently impeded because of the lack of knowledge about prolific taxa for polyketide synthesis and the difficulties in finding and optimizing target microorganisms.

Basic techniques in Microbiology: How to do a Gram Stain

Interesting video showing how to do a Gram stain, a basic laboratory technique in microbiology.

Microbial Exposure During Early Life Has Persistent Effects on Natural Killer T Cell Function

Researchers from Brigham and Women’s Hospital, (Harvard Medical School) have demonstrated that exposure to microbes during early childhood is associated with protection from immune-mediated diseases such as inflammatory bowel disease (IBD) and asthma. In their article researchers show that, in germ-free mice (GF), invariant natural killer T cells (iNKT) accumulate in the colonic lamina propria and lung, resulting in increased morbidity in models of IBD and allergic asthma compared to specific pathogen-free (SPF) mice. This was associated with increased intestinal and pulmonary expression of the chemokine ligand CXCL16, which was associated with increased mucosal iNKT cells. Colonization of neonatal—but not adult—GF mice with a conventional microbiota protected the animals from mucosal iNKT accumulation and related pathology. These results indicate that age-sensitive contact with commensal microbes is critical for establishing mucosal iNKT cell tolerance to later environmental exposures.

Adapted from: Original source

Guided evolution of in silico microbial populations in complexenvironments accelerates evolutionary rates through a step-wiseadaptation

During their lifetime, microbes are exposed to environmental variations, each with its distinct spatio-temporal dynamics. Microbial communities display a remarkable degree of phenotypic plasticity, and highly-fit individuals emerge quite rapidly during microbial adaptation to novel environments. However, there exists a high variability when it comes to adaptation potential, and while adaptation occurs rapidly in certain environmental transitions, in others organisms struggle to adapt. This study investigate the hypothesis that the rate of evolution can both increase or decrease, depending on the similarity and complexity of the intermediate and final environments. Elucidating such dependencies paves the way towards controlling the rate and direction of evolution, which is of interest to industrial and medical application

Results show that the rate of evolution can be accelerated by evolving cell populations in sequential combinations of environments that are increasingly more complex. To quantify environmental complexity, this study evaluate various information-theoretic metrics, and  provide evidence that multivariate mutual information between environmental signals in a given environment correlates well with the rate of evolution in that environment, as measured in study's simulations. The study find that strong positive and negative correlations between the intermediate and final environments lead to the increase of evolutionary rates, when the environmental complexity increases. Horizontal Gene Transfer is shown to further augment this acceleration, under certain conditions. Interestingly, study's simulations show that weak environmental correlations lead to deceleration of evolution, regardless of environmental complexity. Further analysis of network evolution provides a mechanistic explanation of this phenomenon, as exposing cells to intermediate environments can trap the population to local neighborhoods of sub-optimal fitness.

Original Source:

Necrotrophism Is a Quorum-Sensing-Regulated Lifestyle in Bacillus thuringiensis

How pathogenic bacteria infect and kill their host is currently widely investigated. In comparison, the fate of pathogens after the death of their host receives less attention. Researchers have studied Bacillus thuringiensis (Bt) infection of an insect host, and show that NprR, a quorum sensor, is active after death of the insect and allows Bt to survive in the cadavers as vegetative cells.

Data mining the human gut microbiota for therapeutic targets

It is well known that microbes have an intricate role in human health and disease. However, targeted strategies for modulating human health through the modification of either human-associated microbial communities or associated human-host targets have yet to be realized. New knowledge about the role of microbial communities in the microbiota of the gastrointestinal tract (GIT) and their collective genomes, the GIT microbiome, in chronic diseases opens new opportunities for therapeutic interventions.

Anthropology of microbes

In this paper authors describe the need to further integrate the fields of human microbial ecology and anthropology and outline some of the potential goals and benefits of this collaborative work. Interesting and inspiring paper.

Original Source:

Capsule Type of Streptococcus pneumoniae Determines Growth Phenotype

Streptococcus pneumoniae bacteria are responsible for serious human infections including meningitis, pneumonia and bacteraemia and are a common cause of otitis media (ear infection) in children. However, they most often reside harmlessly in the infant nasopharynx. An association has long been observed between the type of polysaccharide capsule surrounding the bacteria and harmless colonization versus invasive disease.

Increased honey bee diversity means fewer pathogens, more helpful bacteria, IU biologist finds

Another first, research also finds probiotic species used by humans flourishing in colonies.

A novel study of honey bee genetic diversity co-authored by an Indiana University biologist has for the first time found that greater diversity in worker bees leads to colonies with fewer pathogens and more abundant helpful bacteria like probiotic species.

MyMicrobes wants to sequence your gut microbiome

MyMicrobes is a social network that is inviting people to have their gut bacteria sequenced for about €1,500. The idea is act as social network and DNA database, offering a place for people to talk about diet tips and gastrointestinal woes.