Social Justice

Social Justice Essay on: racism; School-to Prison Pipeline; Jim Crow; Civil Rights; New Jim Crow; Slavery by Another Name; mass incarcerationhttps://commons.library.stonybrook.edu/writingbeyondtheprison/1016/thumbnail.jp

Mechanisms of biofilm inhibition and degradation by antimicrobial peptides

Many bacteria live as biofilms to cope with unfavourable surroundings. Biofilms start from (i) a planktonic stage, (ii) initial adhesion to surfaces and (iii) formation of sessile micro-colonies that secrete extracellular polymeric substance (EPS), leading to bacterial resistance to antibiotics. Antimicrobial peptides (AMPs) are extensively studied with regard to planktonic bacteria but much less so with regard to biofilm formation. In the present study, we investigated how the above three steps are affected by the properties of the AMPs using a series of peptides composed of six lysines and nine leucines, which differ in their sequences and hence their biophysical properties. Treatment with bactericidal peptides at non-inhibitory concentrations resulted in reduced biofilm growth, for some starting from 25 nM which is 0.2 and 0.4% of their minimum inhibitory concentration (MIC 6.3 and 12.5 μM, respectively), continuing in a dose-dependent manner. We suggest that reduced bacterial adhesion to surfaces and decreased biofilm growth are due to the peptide's ability to coat either the biomaterial surface or the bacterium itself. Degradation of established biofilms by bactericidal and non-bactericidal peptides, within 1 h of incubation, occurs by either killing of embedded bacteria or detachment of live ones. In addition to shedding light on the mechanism of biofilm inhibition and degradation, these data may assist in the design of anti-biofilm AMPs

Allosteric Regulation of Fibronectin/α5β1 Interaction by Fibronectin-Binding MSCRAMMs

Citation: Liang, X. W., Garcia, B. L., Visai, L., Prabhakaran, S., Meenan, N. A. G., Potts, J. R., . . . Hook, M. (2016). Allosteric Regulation of Fibronectin/alpha(5)beta(1) Interaction by Fibronectin-Binding MSCRAMMs. Plos One, 11(7), 17. doi:10.1371/journal.pone.0159118Adherence ofmicrobes to host tissues is a hallmark of infectious disease and is often mediated by a class of adhesins termed MSCRAMMs (Microbial Surface Components Recognizing Adhesive Matrix Molecules). Numerous pathogens express MSCRAMMs that specifically bind the heterodimeric human glycoprotein fibronectin (Fn). In addition to roles in adhesion, Fn-binding MSCRAMMs exploit physiological Fn functions. For example, several pathogens can invade host cells by a mechanism whereby MSCRAMM-bound Fn bridges interaction with alpha(5)beta(1) integrin. Here, we investigate two Fn-binding MSCRAMMs, FnBPA (Staphylococcus aureus) and BBK32 (Borrelia burgdorferi) to probe structure-activity relationships of MSCRAMM-induced Fn/alpha(5)beta(1) integrin activation. Circular dichroism, fluorescence resonance energy transfer, and dynamic light scattering techniques uncover a conformational rearrangement of Fn involving domains distant from the MSCRAMM binding site. Surface plasmon resonance experiments demonstrate a significant enhancement of Fn/alpha(5)beta(1) integrin affinity in the presence of FnBPA or BBK32. Detailed kinetic analysis of these interactions reveal that this change in affinity can be attributed solely to an increase in the initial Fn/alpha(5)beta(1) on-rate and that this rate-enhancement is dependent on high-affinity Fn-binding by MSCRAMMs. These data implicate MSCRAMM-induced perturbation of specific intramolecular contacts within the Fn heterodimer resulting in activation by exposing previously cryptic alpha(5)beta(1) interaction motifs. By correlating structural changes in Fn to a direct measurement of increased Fn/alpha(5)beta(1) affinity, this work significantly advances our understanding of the structural basis for the modulation of integrin function by Fn-binding MSCRAMMs

Effect of Membrane Potential on the Conformation of Bacteriorhodopsin Reconstituted in Lipid Vesicles

The effect of applied diffusion potential on circular dichroism (CD) of bacteriorhodopsin, reconstituted in lipid vesicles, was measured. The change in CD indicates that the applied electrical field, irrespective of its direction, decreases the α-helical fraction and increases the random fraction of the protein. The results are interpreted by unfolding of edges of the helices, upon their submerging into polar environment when the lipid bilayer is electrostricted or (and) the helices are stretched by the electrical field across the membrane

Early Evidence for Northern Salmonid Fisheries Discovered using Novel Mineral Proxies

Salmonid resources currently foster socioeconomic prosperity in several nations, yet their importance to many ancient circumpolar societies is poorly understood due to insufficient fish bone preservation at archaeological sites. As a result, there are serious gaps in our knowledge concerning the antiquity of northern salmonid fisheries and their impacts on shaping biodiversity, hunter-gatherer adaptations, and human-ecological networks. The interdisciplinary study presented here demonstrates that calcium-magnesium phosphate minerals formed in burned salmonid bones can preserve at ancient northern sites, thus informing on the early utilization of these resources despite the absence of morphologically classifiable bones. The minerals whitlockite and beta magnesium tricalcium phosphate were identified in rare morphologically classifiable Atlantic salmonid bones from three Mid-Holocene sites in Finland. Large amounts of beta magnesium tricalcium phosphate were also experimentally formed by burning modern Atlantic salmonid and brown trout bones. Our results demonstrate the value of these minerals as proxies for ancient northern salmonid fishing. Specifically, the whitlockite mineral was discovered in hearth sediments from the 5,600 year old Yli-Ii Kierikinkangas site on the Iijoki River in northern Finland. Our fine sieving and mineralogical analyses of these sediments, along with zooarchaeological identification of recovered bone fragments, have confirmed for the first time that the people living at this village did incorporate salmonids into their economies, thus providing new evidence for early estuary/riverine fisheries in northern Finland.Peer reviewe

High Resolution 3D Imaging of Ex-Vivo Biological Samples by Micro CT

Non-destructive volume visualization can be achieved only by tomographic techniques, of which the most efficient is the x-ray micro computerized tomography (μCT)

Recovery and Enumeration of Staphylococcus aureus by the Selective Agar Overlay Method

Staphylococcus aureus is an example of a commensal bacterium responsible for emesis, acute diarrheal syndrome, and sepsis. S. aureus often must be isolated from patient samples in a clinical setting or from food samples during food processing in an industrial setting, although these bacterial cells may be injured by the human immune system or by food processing measures. Therefore, injured cells may not be fully recovered on media selective for S. aureus and enumeration (e.g., CFU/mL) may not reflect the true concentration of the original sample. The objective of this study was to determine whether the selective agar overlay method of recovery is more sensitive, selective, and time-effective for enumeration of artificially injured S. aureus cultures when compared to more traditional techniques. The selective agar overlay method involves pour plating S. aureus in non-selective medium, allowing the sample to incubate for a four hour recovery period, and then overlaying selective medium over the non-selective medium. Artificial injury of S. aureus cells was accomplished by treatment with carvacrol, an extract from oil of oregano. Our results indicated that carvacrol-injured S. aureus cells were recovered by the selective agar overlay at the same concentration as recovery on non-selective media, and at a significantly higher concentration than recovery on selective media. This method allows for more rapid and accurate diagnoses, and may be more cost-effective due to the reduction or elimination of false negative results

Recovery and Enumeration of Staphylococcus aureus by the Selective Agar Overlay Method

Staphylococcus aureus is an example of a commensal bacterium responsible for emesis, acute diarrheal syndrome, and sepsis. S. aureus often must be isolated from patient samples in a clinical setting or from food samples during food processing in an industrial setting, although these bacterial cells may be injured by the human immune system or by food processing measures. Therefore, injured cells may not be fully recovered on media selective for S. aureus and enumeration (e.g., CFU/mL) may not reflect the true concentration of the original sample. The objective of this study was to determine whether the selective agar overlay method of recovery is more sensitive, selective, and time-effective for enumeration of artificially injured S. aureus cultures when compared to more traditional techniques. The selective agar overlay method involves pour plating S. aureus in non-selective medium, allowing the sample to incubate for a four hour recovery period, and then overlaying selective medium over the non-selective medium. Artificial injury of S. aureus cells was accomplished by treatment with carvacrol, an extract from oil of oregano. Our results indicated that carvacrol-injured S. aureus cells were recovered by the selective agar overlay at the same concentration as recovery on non-selective media, and at a significantly higher concentration than recovery on selective media. This method allows for more rapid and accurate diagnoses, and may be more cost-effective due to the reduction or elimination of false negative results