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Antibiotic resistance represents a growing medical crisis and is predicted to cause over 10 million deaths globally per year by 2050. Among the most dangerous resistant bacteria are the critical priority pathogens denoted by the World Health Organization (WHO). Fortunately, phage therapy, a high potential treatment method that uses viruses to infect and lyse bacteria, can successfully clear antibiotic-resistant infections. However, it has not passed clinical trials due to the lack of a streamlined process for phage characterization, highlighting the need to compare phage host range determination (HRD) techniques to simplify this process. To address this, phage primary research papers with HRD data were collected from PubMed and Google Scholar. 56 suitable studies were grouped by critical priority pathogen and employed HRD technique. The quantity (mL) of agar, phage filtrate, and bacterial culture used was recorded. Means for each group were compared using a non-parametric ANOVA. For the E. coli O157:H7 research paper group, plaque testing used significantly less total material and agar than spot testing with dilutions (p = 0.047, p = 0.041), while spot testing without dilutions used significantly less phage filtrate than plaque testing (p = 0.035) and significantly less bacterial culture than spot testing with dilutions (p = 0.013), strongly suggesting that spot testing with dilutions should not be chosen over other methods when conducting HRD as it is the most resource-consumptive. Further investigation into other phage characterization metrics is warranted.
Bacteriophages are the most abundant biological agent on earth and infect bacteria in order to replicate. During this cycle of infection, there is opportunity for phage-mediated transduction that leads to Horizontal Gene Transfer (HGT), which could lead to increased rate of evolution or virulence in a short time. Strains of the highly virulent Streptococcus pyogenes bacteria were analyzed for the presence of virulence factors (VFs) acquired through phage-mediated HGT. We analyzed bioinformatic data using BLAST, MEGA, and VFDB to look at the VFs of S. pyogenes strains and investigate the extent of HGT occurring among these emerging virulent bacteria. We found that strains with positive HGT contained phage-associated VFs which are absent in the non-HGT strains. Pattern of phylogenetic relatedness of the HGT strains indicates that the HGT may have occurred independently in the strains. Synteny analysis showed a pattern of randomness in the arrangement of genetic elements in the HGT strains, which could be due to the acquisition and retention of phage-associated genes influencing the fitness/virulence of these strains. We want to further this research to investigate how prevalent phage-mediated HGT is in related species and how it is contributing to increasing bacterial virulence.
The presence of small pieces of plastic, termed Microplastics (MP), in the environment is a growing ecological concern, especially for the health of organisms that ingest them, but little is known about which MP characteristics influence their likelihood of ingestion. A small freshwater invertebrate, Daphnia magna, was used to determine if the color or odor of MPs influenced feeding preference in this species. We hypothesized that D. magna would have a preference for green MPs that resembled the color and odor of their algal food source. Experiments exposing D. magna to mixtures of different colored MP fibers, or mixtures of pristine and biofouled MP fibers were conducted. The number of ingested fibers in each intestine was quantified under a fluorescence microscope, using the signature autofluorescence of MP colors, to determine if D. magna exhibited a preference for MP based on color or odor. Our results suggest that D. magna do not exhibit a preference for MPs based on color alone. However, in the presence of odorants (biofouled MPs) a significant preference for black MP over green MP is revealed, suggesting that olfactory cues affect feeding behavior. Our results offer insight into the relationship between MP color and odor, and feeding preference, in D. magna.
Hundreds of species of true bugs (Hemiptera) within the seed bugs, leaf-footed bugs, and allies (superfamilies Lygaeoidea and Coreoidea) depend on symbiotic Caballeronia bacteria which they must acquire from the environment every generation. There has been much recent interest in studying this symbiosis, in part because several of the insects that participate are agricultural pests, and in part because it is an interesting model system for understanding the environmental mode of symbiont acquisition. Researchers who want to rear and study these insects in captivity must ensure that the insects are successfully colonized by Caballeronia, but there is no standard method for doing so. We set out to assess five different methods of exposing insects to these bacteria. We tested the introduction of the bacteria via inoculated water, broth, plant sprig, potting soil, and uninoculated agricultural soil. No significant difference was seen between treatments in average adult weight or development time. However, the method of inoculation did affect the number of insects that reached adulthood. Insects exposed to agricultural soil and symbiont cells in water and were significantly less likely to reach adulthood than insects inoculated via cells in broth, on plant sprigs, or in potting soil. We therefore recommend use of inoculated broth as a simple and effective method to provide true bugs with their symbiotic Caballeronia in laboratory experiments.
Gastric cancer is one of the leading causes of cancer deaths worldwide and is prevalent in East Asian countries, such as China, Japan, and South Korea, which are known to have high salt diets. The HER2 protein, which is often overexpressed in gastric and breast cancer, plays an important role in signaling for cell growth and proliferation. However, the function of the HER2 in relation to a high salt diet is not yet characterized. Salt has been shown to induce the expression of the SIK3 protein, which is associated with inflammation, tumorigenesis, cellular metabolic changes, and cell-cycle progression. The SIK3 protein is activated by Akt, a downstream protein of HER2, but a direct connection between SIK3 and HER2 has not been clearly defined. A mechanism to characterize this potential relationship begins at HER2 activation of PI3K/Akt, leading to mTORC2 activation, followed by Akt phosphorylation. Then, Akt will activate SIK3, which will phosphorylate HDAC4 and expel it from the nucleus, leading to various cellular processes known to induce cancer. If this mechanism is confirmed, it would offer insight into the synergistic effects of the HER2 protein and a high salt diet, converging on the SIK3 protein to promote cancer survival and progression. Therefore, the inhibition of SIK3 could stop cancer-promoting effects and be a useful target for chemotherapy of HER2+ gastric cancer.
Tobacco use and nicotine addiction are leading causes of preventable death and disease. While nicotine addiction is a problem in both males and females, females are more vulnerable to addiction, intense withdrawal symptoms, and relapse. This vulnerability is attributed in part to ovarian hormones estrogen and progesterone, which cycle dynamically throughout the female menstrual cycle. This study used a novel paradigm to examine the effects of progesterone treatment on behavioral withdrawal symptoms following the establishment of nicotine dependence via drinking water in 22 ovariectomized female rats. We predicted that rats treated with progesterone would exhibit less severe nicotine withdrawal symptoms than the control rats. We were unable to determine the role of progesterone in nicotine withdrawal as nicotine dependence was not established; however, this topic is relevant for future clinical use in treating nicotine withdrawal symptoms, particularly in females. By investigating the role of progesterone in female smokers, more effective treatments can be developed to mitigate withdrawal symptoms upon nicotine cessation and accommodate females struggling with addiction.
Exposure to illumination from LED (light emitting diode) light may be an unsuspecting cause of human health problems, including cellular growth disruptions and cardiovascular issues. Vertebrate hearts comprise multiple chambers that create a rhythm resulting in continuous blood flow, which, if insufficient results in the heart retaining fluid. Here we report a preliminary study of the effect of exposing wild-type Danio rerio (zebrafish) embryos to 6500K, White, LED light on development of pericardial edema. Embryos were exposed to LED light from 12 hours post fertilization for 72 hours in one of the following conditions: (1) no exposure, (2) light/dark cycle of 12 hours/12 hours, and (3) 72 consecutive hours. Results indicated a significant relationship between exposure to LED lighting and pericardial edema; a significant relationship was seen between length of exposure and severity of pericardial edema. Pericardial edema became noticeable after 48 hours of light exposure. Further research should explore the effects of different wavelengths of LEDs on development of pericardial edema. Molecular studies might examine how LED exposure alters transcription factors involved in cardiac development.
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