Bioanalytical Assay of Antimicrobial Polymers Binding to Bacterial Cells

Branched polyethylenimine (BPEI) has an antimicrobial effect on bacteria. The killing mechanism of BPEI centers on its cationic properties. The mechanism of action against Gram-positive bacteria is less understood but recent reports erroneously suggest that membrane depolarization occurs. To the contrary, data from our laboratory suggests that BPEI binds to the anionic sites provided by the biopolymer wall teichoic acid (WTA). To test the validity of this hypothesis, we measure the amount BPEI binding to whole, intact, bacterial cells of Bacillus subtilis. Comparative measurements are made with Bacillus subtilis bacteria that contain WTA and Bacillus subtilis genetic mutants that lack WTA. Using equilibrium dialysis, Bacillus subtilis bacteria were exposed to different solution concentrations of BPEI. Removal of small aliquots from solution and subsequent assay with the ninhydrin test were used to measure the amount of BPEI remaining in solution and the amount of BPEI bound to the bacterial cell walls. These data were used to obtain the amount of bound vs. unbound BPEI and determine the equilibrium constant. These data influence the understanding of BPEI antimicrobial properties and impacts the development of antibiotics to treat human disease

Single nucleotide polymorphisms (SNPs) distinguish Indian-origin and Chinese-origin rhesus macaques (Macaca mulatta)

BACKGROUND: Rhesus macaques serve a critical role in the study of human biomedical research. While both Indian and Chinese rhesus macaques are commonly used, genetic differences between these two subspecies affect aspects of their behavior and physiology, including response to simian immunodeficiency virus (SIV) infection. Single nucleotide polymorphisms (SNPs) can play an important role in both establishing ancestry and in identifying genes involved in complex diseases. We sequenced the 3' end of rhesus macaque genes in an effort to identify gene-based SNPs that could distinguish between Indian and Chinese rhesus macaques and aid in association analysis. RESULTS: We surveyed the 3' end of 94 genes in 20 rhesus macaque animals. The study included 10 animals each of Indian and Chinese ancestry. We identified a total of 661 SNPs, 457 of which appeared exclusively in one or the other population. Seventy-nine additional animals were genotyped at 44 of the population-exclusive SNPs. Of those, 38 SNPs were confirmed as being population-specific. CONCLUSION: This study demonstrates that the 3' end of genes is rich in sequence polymorphisms and is suitable for the efficient discovery of gene-linked SNPs. In addition, the results show that the genomic sequences of Indian and Chinese rhesus macaque are remarkably divergent, and include numerous population-specific SNPs. These ancestral SNPs could be used for the rapid scanning of rhesus macaques, both to establish animal ancestry and to identify gene alleles that may contribute to the phenotypic differences observed in these populations

Single Nucleotide Polymorphisms (SNPs) Distinguish Indian-Origin and Chinese-Origin Rhesus Macaques (Macaca Mulatta)

BACKGROUND: Rhesus macaques serve a critical role in the study of human biomedical research. While both Indian and Chinese rhesus macaques are commonly used, genetic differences between these two subspecies affect aspects of their behavior and physiology, including response to simian immunodeficiency virus (SIV) infection. Single nucleotide polymorphisms (SNPs) can play an important role in both establishing ancestry and in identifying genes involved in complex diseases. We sequenced the 3\u27 end of rhesus macaque genes in an effort to identify gene-based SNPs that could distinguish between Indian and Chinese rhesus macaques and aid in association analysis. RESULTS: We surveyed the 3\u27 end of 94 genes in 20 rhesus macaque animals. The study included 10 animals each of Indian and Chinese ancestry. We identified a total of 661 SNPs, 457 of which appeared exclusively in one or the other population. Seventy-nine additional animals were genotyped at 44 of the population-exclusive SNPs. Of those, 38 SNPs were confirmed as being population-specific. CONCLUSION: This study demonstrates that the 3\u27 end of genes is rich in sequence polymorphisms and is suitable for the efficient discovery of gene-linked SNPs. In addition, the results show that the genomic sequences of Indian and Chinese rhesus macaque are remarkably divergent, and include numerous population-specific SNPs. These ancestral SNPs could be used for the rapid scanning of rhesus macaques, both to establish animal ancestry and to identify gene alleles that may contribute to the phenotypic differences observed in these populations

Feasibility and acceptability of a technology-based, rural weight management int ervention in older adults with obesity

Background Older adults with obesity residing in rural areas have reduced access to weight management programs. We determined the feasibility, acceptability and preliminary outcomes of an integrated technology-based health promotion intervention in rural-living, older adults using remote monitoring and synchronous video-based technology. Methods A 6-month, non-randomized, non-blinded, single-arm study was conducted from October 2018 to May 2020 at a community-based aging center of adults aged ≥65 years with a body mass index (BMI) ≥30 kg/m2. Weekly dietitian visits focusing on behavior therapy and caloric restriction and twice-weekly physical therapist-led group strength, flexibility and balance training classes were delivered using video-conferencing to participants in their homes. Participants used a Fitbit Alta HR for remote monitoring with data feedback provided by the interventionists. An aerobic activity prescription was provided and monitored. Results Mean age was 72.9±3.9 years (82% female). Baseline anthropometric measures of weight, BMI, and waist circumference were 97.8±16.3 kg, 36.5±5.2 kg/m2, and 115.5±13.0 cm, respectively. A total of 142 participants were screened (n=27 ineligible), and 53 consented. There were nine dropouts (17%). Overall satisfaction with the trial (4.7+ 0.6, scale: 1 (low) to 5 (high)) and with Fitbit (4.2+ 0.9) were high. Fitbit was worn an average of 81.7±19.3% of intervention days. In completers, mean weight loss was 4.6±3.5 kg or 4.7±3.5% (p\u3c 0.001). Physical function measures of 30-s sit-to-stand repetitions increased from 13.5±5.7 to 16.7±5.9 (p\u3c 0.001), 6-min walk improved by 42.0±77.3 m (p=0.005) but no differences were observed in gait speed or grip strength. Subjective measures of late-life function improved (3.4±4.7 points, p\u3c 0.001). Conclusions A technology-based obesity intervention is feasible and acceptable to older adults with obesity and may lead to weight loss and improved physical function. Clinical trial registration Registered on Clinicaltrials.gov #NCT03104205. Registered on April 7, 2017. First participant enrolled on October 1st, 2018

Possible Fruit Protein Effects on Primate Communities in Madagascar and the Neotropics

The ecological factors contributing to the evolution of tropical vertebrate communities are still poorly understood. Primate communities of the tropical Americas have fewer folivorous but more frugivorous genera than tropical regions of the Old World and especially many more frugivorous genera than Madagascar. Reasons for this phenomenon are largely unexplored. We developed the hypothesis that Neotropical fruits have higher protein concentrations than fruits from Madagascar and that the higher representation of frugivorous genera in the Neotropics is linked to high protein concentrations in fruits. Low fruit protein concentrations in Madagascar would restrict the evolution of frugivores in Malagasy communities.We reviewed the literature for nitrogen concentrations in fruits from the Neotropics and from Madagascar, and analyzed fruits from an additional six sites in the Neotropics and six sites in Madagascar. Fruits from the Neotropical sites contain significantly more nitrogen than fruits from the Madagascar sites. Nitrogen concentrations in New World fruits are above the concentrations to satisfy nitrogen requirements of primates, while they are at the lower end or below the concentrations to cover primate protein needs in Madagascar.Fruits at most sites in the Neotropics contain enough protein to satisfy the protein needs of primates. Thus, selection pressure to develop new adaptations for foods that are difficult to digest (such as leaves) may have been lower in the Neotropics than in Madagascar. The low nitrogen concentrations in fruits from Madagascar may contribute to the almost complete absence of frugivorous primate species on this island

EFFECTS OF PLANT SENESCENCE ON WATER QUALITY IN A SMALL, SEMI-ISOLATED FRESHWATER WETLAND

Water quality is a function of concomitant physicochemical conditions and biological processes. Such conditions and processes may include: rainfall, contaminant sources, atmospheric conditions, flora, and fauna. In small water bodies, aquatic vegetation and algal communities can serve a disproportionate role in biogeochemical cycles because these systems do not regularly mix with other surface water inflows and outflows. Seasonal photosynthetic activity drives dissolved oxygen / carbon dioxide dynamics which in turn drive pH cycles. Fall senescence may drive important water quality changes in small wetlands through cessation of growing season photosynthesis and influx of coarse organic matter (e.g. leaf litter). Our objective is to quantify changes in water quality related to plant senescence in a small, semi-isolated, freshwater wetland on Saint Simons Island, GA. A Hydrolab MS5 sonde was used to measure dissolved oxygen, pH, specific conductivity, and temperature weekly beginning 10/19/2018 (prior to plant senescence) through 11/30/2018 (late stages of senescence). Turbidity was measured using a HACH 2100Q turbidimeter for the same period of record. Preliminary findings show dissolved oxygen increased during plant senescence, likely due to decreasing temperatures. Specific conductivity decreased which may be caused by increased precipitation diluting soil water inputs during late autumn. Turbidity and pH have not yet shown a response to plant senescence. Measurements will continue through the winter and into the next growing season. Small, freshwater wetlands on barrier islands are understudied relative to nearby saltmarshes. Therefore, our findings provide baseline conditions to compare future water quality monitoring in small semi-isolated wetlands on the Georgia Coast