Chromosome architecture as a determinant for biosynthetic diversity in .

Natural products - small molecules generated by organisms to facilitate ecological interactions - are of great importance to society and are used as antibacterial, antiviral, antifungal and anticancer drugs. However, the role and evolution of these molecules and the fitness benefits they provide to their hosts in their natural habitat remain an outstanding question. In bacteria, the genes that encode the biosynthetic proteins that generate these molecules are organised into discrete loci termed biosynthetic gene clusters (BGCs).

Oxytetracycline hyper-production through targeted genome reduction of .

Most biosynthetic gene clusters (BGC) encoding the synthesis of important microbial secondary metabolites, such as antibiotics, are either silent or poorly expressed; therefore, to ensure a strong pipeline of novel antibiotics, there is a need to develop rapid and efficient strain development approaches. This study uses comparative genome analysis to instruct rational strain improvement, using , the producer of the important antibiotic oxytetracycline (OTC) as a model system. Sequencing of the genomes of two industrial strains M4018 and R6-500, developed independently from a common ancestor, identified large DNA rearrangements located at the chromosome end.

Effect of trimethylamine--oxide on the phase separation of aqueous polyethylene glycol-600-Dextran-75 two-phase systems.

The emergence of phase separation in both intracellular biomolecular condensates (membrane-less organelles) and aqueous two-phase systems (ATPS) relies on the formation of immiscible water-based phases/domains. The solvent properties and arrangement of hydrogen bonds within these domains have been shown to differ and can be modulated with the addition of various inorganic salts and osmolytes. The naturally occuring osmolyte, trimethylamine--oxide (TMAO), is well established as a biological condensate stabilizer whose presence results in enhanced phase separation of intracellular membrane-less compartments.

sp. nov., an actinomycete isolated from solar saltern soil.

An actinobacterium, designated strain SS06011, was isolated from solar saltern soil collected from Samut Sakhon province, Thailand. The taxonomic position of this strain was established using the polyphasic taxonomic approach. The strain produced grey aerial spore mass on International Project 2 seawater agar that differentiated into spiral spore chains with rugose-surfaced spores.

Phosphoproteome Dynamics of Streptomyces rimosus during Submerged Growth and Antibiotic Production.

Streptomyces rimosus is an industrial streptomycete, best known as a producer of oxytetracycline, one of the most widely used antibiotics. Despite the significant contribution of species to the pharmaceutical industry, most omics analyses have only been conducted on the model organism Streptomyces coelicolor. In recent years, protein phosphorylation on serine, threonine, and tyrosine (Ser, Thr, and Tyr, respectively) has been shown to play a crucial role in the regulation of numerous cellular processes, including metabolic changes leading to antibiotic production and morphological changes.

Bilateral symmetry of linear streptomycete chromosomes.

Here, we characterize an uncommon set of telomeres from ATCC 10970, the parental strain of a lineage of one of the earliest-discovered antibiotic producers. Following the closure of its genome sequence, we compared unusual telomeres from this organism with the other five classes of replicon ends found amongst streptomycetes. Closed replicons of streptomycete chromosomes were organized with respect to their phylogeny and physical orientation, which demonstrated that different telomeres were not associated with particular clades and are likely shared amongst different strains by plasmid-driven horizontal gene transfer.

Genome editing reveals that pSCL4 is required for chromosome linearity in .

is an industrially important actinomycete whose genetic manipulation is limited by low transformation and conjugation efficiencies, low levels of recombination of introduced DNA, and difficulty in obtaining consistent sporulation. We describe the construction and application of versatile vectors for Cas9-mediated genome editing of this strain. To design spacer sequences with confidence, we derived a highly accurate genome assembly for an isolate of the type strain (ATCC 27064).

Adaptation to Endophytic Lifestyle Through Genome Reduction by sp. SUK42.

Endophytic actinobacteria offer great potential as a source of novel bioactive compounds. In order to investigate the potential for the production of secondary metabolites by endophytes, we recovered a filamentous microorgansism from the tree Miq. After phenotypic analysis and whole genome sequencing we demonstrated that this organism, SUK42 was a member of the actinobacterial genus .

Comparing scientific worldviews between allopathic medical degree and East Asian medicine degree students utilizing the thinking about science survey instrument (TSSI).

Background: Integrative medicine has become a new healthcare model due to the growing evidence base for complementary and integrative therapies. However, some question whether complementary and integrative therapies can truly be integrated with biomedicine due to differences in underlying paradigms and theoretical bases. This study aimed to explore differences in scientific worldviews between students studying East Asian medicine and those completing an allopathic medical degree using the validated Thinking about Science Survey Instrument (TSSI).

Differential transcription of expanded gene families in central carbon metabolism of A3(2).

Background: Streptomycete bacteria are prolific producers of specialized metabolites, many of which have clinically relevant bioactivity. A striking feature of their genomes is the expansion of gene families that encode the same enzymatic function. Genes that undergo expansion events, either by horizontal gene transfer or duplication, can have a range of fates: genes can be lost, or they can undergo neo-functionalization or sub-functionalization.

Current Perspectives on the Impact of Pre-Exposure Prophylaxis Stigma Regarding Men Who Have Sex with Men in the United States.

Pre-exposure prophylaxis or PrEP is a Food and Drug Administration approved human immunodeficiency virus (HIV) prevention tool that reduces the risk of infection by greater than 90%. While it does not provide protection against other sexually transmittable infections and blood-borne illnesses such as hepatitis C, syphilis, chlamydia, and gonorrhea, it is a highly effective in reducing the risk of transmission of HIV among men who have sex with men. Despite the success of PrEP, there remain barriers to PrEP uptake rooted in stigmatized perspectives shared by health professionals, patients, and community members.

Streptomyces altiplanensis sp. nov., an alkalitolerant species isolated from Chilean Altiplano soil, and emended description of Streptomyces chryseus (Krasil'nikov et al. 1965) Pridham 1970.

A polyphasic approach was used for evaluating the taxonomic status of strain HST21 isolated from Salar de Huasco in the Atacama Desert. The results of 16S rRNA gene and multilocus sequence phylogenetic analyses assigned strain HST21 to the genus Streptomyceswith Streptomyces albidochromogenes DSM 41800and Streptomyces flavidovirens DSM 40150 as its nearest neighbours. Digital DNA-DNA hydridization (dDDH) and average nucleotide identity (ANI) values between the genome sequences of strain HST21 and S.

An Ethical Obligation for Bioethicists to Utilize Social Media.

In this issue of the Hastings Center Report, Mélanie Terrasse, Moti Gorin, and Dominic Sisti respond to recent efforts to address the "digital attention crisis," arguing that "[b]ioethicists should make their voices heard in the debate on the responsibilities of social media companies toward their consumers and society at large." I strongly agree. I have frequently been asked by my colleagues why I spend time on social media professionally, on top of all the competing demands associated with my work as a bioethicist and medical educator.

Rapid colorimetric lactoferrin-based sandwich immunoassay on cotton swabs for the detection of foodborne pathogenic bacteria.

Cotton swab is the conventional swabbing tool that is usually applied for collecting pathogens from contaminated surfaces, followed by cells lysis and DNA extraction before subjecting to genetic analysis. However, such an approach is time consuming as it involves several steps and requires highly trained personnel to perform the experiment. In this study, we developed a new cotton swab-based detection system that involved integrating bacterial collection, preconcentration and detection on Q-tips.

How Should Social Media Be Used in Transplantation? A Survey of the American Society of Transplant Surgeons.

Background: Social media platforms are increasingly used in surgery and have shown promise as effective tools to promote deceased donation and expand living donor transplantation. There is a growing need to understand how social media-driven communication is perceived by providers in the field of transplantation.

Methods: We surveyed 299 members of the American Society of Transplant Surgeons about their use of, attitudes toward, and perceptions of social media and analyzed relationships between responses and participant characteristics.

A Calling to Professionalism.

This article was migrated. The article was marked as recommended. The editor for this theme issue on Accessing Medical Education has asked authors to reflect on how they came to be the medical education professional they are today.

Unique Function of the Bacterial Chromosome Segregation Machinery in Apically Growing Streptomyces - Targeting the Chromosome to New Hyphal Tubes and its Anchorage at the Tips.

The coordination of chromosome segregation with cell growth is fundamental to the proliferation of any organism. In most unicellular bacteria, chromosome segregation is strictly coordinated with cell division and involves ParA that moves the ParB nucleoprotein complexes bi- or unidirectionally toward the cell pole(s). However, the chromosome organization in multiploid, apically extending and branching Streptomyces hyphae challenges the known mechanisms of bacterial chromosome segregation.

Who's misbehaving? Perceptions of unprofessional social media use by medical students and faculty.

Background: Social media use by physicians offers potential benefits but may also be associated with professionalism problems. The objectives of this study were: 1) to examine and compare characteristics of social media use by medical students and faculty; 2) to explore the scope of self- and peer-posting of unprofessional online content; and 3) to determine what actions were taken when unprofessional content was viewed.

Methods: An anonymous, web-based survey was sent to medical students and faculty in October, 2013 at the Albert Einstein College of Medicine in Bronx, New York.

Ethical Implications of Social Stigma Associated with the Promotion and Use of Pre-Exposure Prophylaxis for HIV Prevention.

Identifying sources of and eliminating social stigma associated with the promotion and use of pre-exposure prophylaxis (PrEP) for the prevention of sexually acquired HIV infection among men who have sex with men (MSM) is both a moral imperative and necessary requirement to ensure that public health objectives of HIV prevention can be met. This article will examine and address ethical concerns and criticisms regarding the use of PrEP, barriers to its promotion, and use among MSM and examine the types of social stigma associated with PrEP. An ethical justification for both healthcare and LGBT communities to address and overcome social stigma regarding the use of PrEP among MSM is offered.

Plasticity of Streptomyces coelicolor Membrane Composition Under Different Growth Conditions and During Development.

Streptomyces coelicolor is a model actinomycete that is well known for the diversity of its secondary metabolism and its complex life cycle. As a soil inhabitant, it is exposed to heterogeneous and frequently changing environmental circumstances. In the present work, we studied the effect of diverse growth conditions and phosphate depletion on its lipid profile and the relationship between membrane lipid composition and development in S.

In vivo antimalarial activity of the endophytic actinobacteria, Streptomyces SUK 10.

Endophytic bacteria, such as Streptomyces, have the potential to act as a source for novel bioactive molecules with medicinal properties. The present study was aimed at assessing the antimalarial activity of crude extract isolated from various strains of actinobacteria living endophytically in some Malaysian medicinal plants. Using the four day suppression test method on male ICR strain mice, compounds produced from three strains of Streptomyces (SUK8, SUK10, and SUK27) were tested in vivo against Plasmodium berghei PZZ1/100 in an antimalarial screen using crude extracts at four different concentrations.

Opportunities and ethical challenges for the practice of medicine in the digital era.

Technological advances have been a driving force in the practice of medicine. From the discovery of x-rays' medical applications to the utilization of dialysis and surgical transplantation of organs, technology has presented new opportunities, and at times, ethical challenges for physicians. In recent years, the increased proliferation of social media tools has had a significant impact on how people engage with one another, and how they want to engage with their healthcare providers.

Construction of a new class of tetracycline lead structures with potent antibacterial activity through biosynthetic engineering.

Antimicrobial resistance and the shortage of novel antibiotics have led to an urgent need for new antibacterial drug leads. Several existing natural product scaffolds (including chelocardins) have not been developed because their suboptimal pharmacological properties could not be addressed at the time. It is demonstrated here that reviving such compounds through the application of biosynthetic engineering can deliver novel drug candidates.

Inactivation of phage ɸC31 by 405 nm light: Requirement for exogenous photosensitizers?

Exposure to narrowband violet-blue light around 405 nm wavelength can induce lethal oxidative damage to bacteria and fungi, however effects on viruses are unknown. As photosensitive porphyrin molecules are involved in the microbicidal inactivation mechanism, and since porphyrins are absent in viruses, then any damaging effects of 405 nm light on viruses might appear unlikely. This study used the bacteriophage ɸC31, as a surrogate for non-enveloped double-stranded DNA viruses, to establish whether 405 nm light can induce virucidal effects.