Previous studies have shown that human platelets and megakaryocytes carry microRNAs suggesting their role in platelet function and megakaryocyte development, respectively. However, there is limited information on microRNAs' role in zebrafish thrombopoiesis. Zebrafish thrombocytes could be used as a model to study their role in megakaryocyte maturation and platelet function because thrombocytes have both megakaryocyte features and platelet properties. In our laboratory, I identified 15 microRNAs in thrombocytes using single-cell RNA sequencing. Knockdown of three microRNAs, mir-7148, let-7b, and mir-223, by the piggyback method in zebrafish led to an increase in the percentage of thrombocytes. Functional thrombocyte analysis using plate tilt assay showed no modulatory effect of the three microRNAs on thrombocyte aggregation/agglutination. I then verified these findings in zebrafish larvae after the knockdown of the above microRNAs followed by an arterial laser thrombosis assay. I concluded mir-7148, let-7b, and mir-223 are repressors for thrombocyte production. Furthermore, I explored let-7b downstream genes in thrombocytes detected by RNA-seq analysis and chose 14 targets based on their role in cell differentiation (rorca, tgif1, rfx1a, deaf1, zbtb18, mafba, cebpa, spi1a, spi1b, fhl3b, ikzf1, irf5, irf8, and lbx1b) that are transcriptional regulators. The qRT-PCR analysis of expression levels the above genes following let-7b knockdown …

Invasions from coho salmon were first reported in the Cape Horn Biosphere Reserve (CHBR) in 2019 which is the most southern distribution registered to date. The CHBR is known for its high number of endemic species and unique biodiversity, such as the native fishes Galaxias maculatus and Aplochiton taeniatus. There are now three invasive salmonid species in the rivers of CHBR and are a potential threat to the native fish taxa. Stable isotope and gut content analysis were used to understand resource utilization by both native galaxiid and invasive salmonid taxa, as well as aquatic macroinvertebrates and riparian spiders. The natural laboratory study approach applied to this research, allowed for comparisons of differences within streams that contain conditions in which fish do not occur naturally, to sites in which high densities of invasive salmonid exist. Analysis of the trophic niche and diet in this study showed the importance of marine resource use by the native galaxiid and coho salmon juveniles supported with elevated δ15N and δ34S ratios. Diet analysis also confirmed there was the highest similarity between the coho salmon juveniles and the native fish. Altered behavior and habitat use was shown through the isotope and diet analysis for the …

Conservation corridors, areas of land connecting patches of natural land cover, are frequently cited and implemented as a restorative strategy to counteract fragmentation. Current corridor ecology focuses on experimental corridor systems or designed and built conservation corridors to assess functionality. Such systems and designs are typically short, straight swaths of homogenous land cover with unambiguous transitions between patches. Quantifying the degree to which amorphous landscape configurations, tortuosity, and heterogeneity of land cover and land uses within the corridor has on functional connectedness is a crucial yet overlooked component of corridor efficacy studies. Corridor literature lacks a robust and repeatable methodology for delineating existing landscape elements, recognizing arbitrary edges, and identifying the start and end of ambiguous transitions between the patches and corridor. Using a set of landscapes being studied as part of a global assessment of corridor efficacy, I designed a workflow that standardizes the boundary of corridor-patch interfaces. The proposed method is a quantitative and repeatable approach that minimizes the subjectivity in corridor delineations. This research investigates the degree to which the existence of a corridor modifies the structural and functional connectivity between patches connected by a corridor compared to an intact reference area.

My thesis focuses on the conservation consequences of the hybridization of Lesser Prairie-Chickens in Kansas. Specifically, examining how past land management practices altering the species ranges impact the distinctiveness of Lesser Prairie-Chickens. Each chapter is an individual publication that addresses if the Greater and Lesser Prairie-Chicken are distinct when applying the morphological and biological species concepts. Chapter 2 compares the evolutionary history and morphological construct of Lesser Prairie-Chickens and other Galliformes using morphometric analysis. Chapter 3 uses low-resolution microsatellite data to reflect recent changes at the population level. This study aims to observe the Greater and Lesser Prairie-Chicken using the morphological and biological species concepts, two of the many species concepts, to determine the distinctiveness and rate of hybridization for these closely related species.

Crude oil commonly enters freshwater aquatic ecosystems as thin sheens forming on the water surface. Oil contains mixtures of toxic compounds called polycyclic aromatic hydrocarbons (PAHs), some of which are known to be photodynamic, increasing toxicity when combined with ultraviolet radiation. Benthic macroinvertebrate communities are commonly utilized as bioindicators, and as such rely on abundant data in literature concerning benthic macroinvertebrates' relative tolerances to a wide range of pollutants. A series of 10 plastic traps, half of which were filtered from UV radiation, were deployed in an urban pond for 27 days to determine colonization preferences of benthic macroinvertebrates to UV exposure. Results of this in situ experiment indicated that the majority of aquatic insects collected from traps inhabited the UV exposed treatment group, particularly the nonbiting midge, Chironomidae. A series of bioassays were then completed to investigate the sensitivities of a Chironomidae species to thin sheens of crude oil in the presence and absence of UV radiation. All bioassays were conducted using 10 day old Chironomus dilutus larvae cultured in the lab. The series of C. dilutus bioassays were all conducted under the same water quality parameters, temperatures, and oil sheen dosing methods, under a 16:8 photoperiod and exposed …

This dissertation aimed to explore the S2 region with an attempt to modulate its elasticity in order to tune the contraction output. Two peptides, the stabilizer and destabilizer, showed high potential in modifying the S2 region at the cellular level, thus they were prepared for animal model testing. In this research, (i) S2 elasticity was studied, and the stabilizer and destabilizer peptides were built to tune contraction output through modulating S2 flexibility; (ii) the peptides were attached to heart homing adducts and the bond between them was confirmed; and (iii) it was shown that minor changes were imposed on the modulating peptides' functionality upon attaching to the heart homing adducts. S2 flexibility was confirmed through comparing it to other parts of myosin using simulated force spectroscopy. Modulatory peptides were built and computationally tested for their efficacy through interaction energy measurement, simulated force spectroscopy and molecular dynamics; these were attached to heart homing adducts for heart delivery. Interaction energy tests determined that tannic acid (TA) served well for this purpose. The stoichiometry of the bond between the TA and the modulating peptides was confirmed using mass spectroscopy. The functionality of the modulating peptides was shown to be unaltered through expansion microscopy …

Current evidence suggests that thyroid hormones (THs) may impact development of the immune system. However, studies that explore the role of THs in immune development are limited, and the mechanisms leading to alterations in immune function are poorly understood. It is important to elucidate the role of THs in immune development given that many environmental contaminants have been shown to disrupt TH homeostasis and may also have negative impacts on the immune system. As such, the main goal of this study was to determine the long-term consequences of early life stage (ELS) hypothyroidism on immune function. To achieve this goal, it was first necessary to further characterize basic immune function in the selected model species, the fathead minnow (FHM, Pimephales promelas). Preliminary studies were conducted to describe the transcriptomic response to Yersinia ruckeri and adapt assays for the assessment of respiratory burst and phagocytic cell activity. To determine the long-term effects of ELS hypothyroidism, FHMs were exposed to the model thyroid suppressant propylthiouracil (PTU) from <1 to 30 days post hatch and reared under normal conditions. Upon reaching adulthood, ex vivo immune cell function and the in vivo immune response to Y. ruckeri were assessed. Fish exposed to PTU experienced …

Improving growth, lowering mortality rates, and having a faster turnaround to harvest is essential for the future of commercial aquaculture. The primary goal of this study was to determine if introducing a single strain probiotic Lactobacillus rhamnosus IMC 501 into the feed regimen of a commercially important aquaculture freshwater fish, Mozambique tilapia (Oreochromis mossambicus), would decrease mortality; change metabolic rates; and increase tissue wet mass (MW), standard length, growth rate and feed conversion rate (FCRs). IMC501 was added to the fishmeal in four increasing concentrations and compared to a control without probiotics. Results from two-way ANOVAs showed that both treatment levels and elapsed time had a significant effect on both mean standard length and wet mass; in the latter case, time points and treatments interacted with one another, showing that tilapia grew best with a moderate level of probiotics present. The growth benefits of probiotics continued for months after the initial treatments. Oxygen consumption (metabolic rate) was measured using closed respirometry and resulted in recording the first values for juvenile tilapia treated with probiotics. For oxygen consumption, there were significant treatment and time effects with significant interactions, indicating that metabolism increased with probiotics once the dosage exceeded three times the …

Fusarium head blight (FHB) is an important disease of small grain cereals including wheat that affects grain quality and yield. The fungus Fusarium graminearum (Fg) is the major agent of this disease. Lack of natural resistance has limited ability to control wheat losses to this disease. Developing new approaches is critical for increasing host plant resistance to this fungus. This work has identified four processes that can be targeted for enhancing host plant resistance to FHB. The first involves targeting the pattern-triggered immunity mechanism to promote host plant resistance. Two other approaches involved reducing activity of susceptibility factors in the host to enhance plant resistance. The susceptibility factors targeted include accumulation of the phytohormone jasmonic acid and the 9-lipoxygenase pathway that oxidizes fatty acids. Besides suppressing host defenses against Fg, jasmonic acid also directly acts on the fungus to promote fungal growth. 9- lipoxygenases similarly suppress host defenses to promote fungal pathogenicity. Another approach that was developed involved having the plant express double stranded RNA to target fungal virulence genes for silencing. This host-induced gene silencing approach was employed to target two fungal virulence genes, the lipase encoding FGL1 and salicylate hydroxylase encoding FgNahG, which the fungus secretes into the …

This study shows that Arabidopsis thaliana WRKY45 gene has an important role in limiting green peach aphid (GPA; Myzus persicae Sülzer) infestation. WRKY45 belongs to the WRKY family of transcription factors, which is one of the largest transcription factor family in plants. In response to GPA infestation, expression of WRKY45 was systemically upregulated in leaves and roots, with highest expression in the vascular tissues, which are the site of aphid feeding. GPA colonization was better on the wrky45 mutant compared to the wild-type (WT) plant. In contrast, GPA poorly colonized plants that were overexpressing (OE) WRKY45, thus confirming an important role for WRKY45 in plant defense to the GPA. A WRKY45-dependent process adversely impacted the reproductive rate of GPA and feeding from the sieve elements. RNA-seq experiments indicated a major impact of WRKY45 overexpression on expression of genes associated with dehydration and abscisic acid biosynthesis and signaling. In agreement with the RNA-seq data, ABA content was also higher in WRKY45-OE plants. However, genetic studies with an ABA-insensitive mutant (abi2-2) indicates that the WRKY45-OE conferred resistance to GPA is mediated through an ABA-independent mechanism. WRKY45-OE plants showed enhanced tolerance to drought and salt stresses. Genetic studies indicate that ABA signaling is …

Considering the high reproductive investment of the social male and the cost to the female of losing this benefit by soliciting copulations outside the social pair bond, it is expected that most raptor populations would exhibit low to no occurrence of extra-pair paternity (EPP). This holds true for the majority of raptor species studied to date with only one exception of an urban Cooper's hawk (Accipiter cooperii) study which reported an unexpectedly high extra-pair young frequency of 19.29%. In our study we examined the frequency of EPP within a red-shouldered hawk (Buteo lineatus) population residing in the suburban/urban matrix of southwest Ohio. During the breeding seasons of 2018 and 2019, 181 breeding age and nestling individuals were color-banded and sampled for genetic analysis using nine microsatellite loci. After genotyping a total of 40 broods (with at least two nestlings per brood) and both presumptive parents of each brood, no clear evidence of EPP was detected. However, at one nest site, the entire brood of four chicks was not sired by the adult male observed during the courtship period, nor another adult male observed tending the chicks later in the season. We suspect that this particular nest represented two instances of …

While female mimicry and lower status signaling hypotheses of delayed plumage maturation have received much discussion in the literature, the experimental tests of these hypotheses have been infrequent. Those experimental tests often use a simulated intruder method with artificial model intruders rather than using live conspecific birds as intruders. Subadult male painted buntings (Passerina ciris) possess delayed plumage maturation where they appear visually identical to adult females during their first potential breeding season, while adult males are strikingly different in plumage coloration. Here I test the behavioral responses in a territorial population of painted buntings that exhibits extreme delayed plumage maturation using a simulated territorial intrusion experiment to measure territorial male behavioral response when presented with live caged intruders of both subadult and adult males. Territorial adult males were significantly more likely to initiate an attack and continue to attack caged adult male intruders than compared to caged subadult male intruders. This result supports both the female mimicry and status signaling hypotheses, and does not support the cryptic hypothesis. Additionally, in anecdotal observations, territorial males occasionally performed mating display behaviors to caged subadult male intruders. These results further suggest that territorial male painted buntings may identify subadult males as potential …

The Magellanic woodpecker (Campephilus magellanicus), the largest woodpecker in Central and South America, is declining throughout its range. Notably, limited research has been conducted on the Campephilus genus, especially for island populations. Mostly during austral summers 2015-2017, I explored the ecological importance and population structure of Magellanic woodpeckers on Navarino Island, Chile (55°04′S, 67°40′W). First, I assessed how coleopteran larval density and distribution within trees may influence Magellanic woodpecker foraging behavior. Second, I designed an experiment to determine which of three detection methods would best elicit a woodpecker detection. Third, I conducted a population genetics study to elucidate trends within and among Magellanic woodpecker populations to better inform management decisions. I identified two coleopteran species: one lucanid (Erichius femoralis) and one cerambycid (Microplophorus magellanicus) within two lenga (Nothofagus pumilio) trees foraged on by Magellanic woodpeckers. Maximum woodpecker excavation depths were 71-90 mm; most larval gallery depths were 51-70 mm. The drumming device most effectively influenced the likelihood of a woodpecker detection. The odds of a woodpecker responding were 2.14 times more likely than responding to either a playback or control. On Navarino Island, I observed a pattern of isolation by distance among sampled woodpeckers, slight female sex-biased dispersal, and family …

Microtubules (MT) are regulated by multiple categories of proteins, including proteins responsible for severing MTs that are therefore called MT-severing proteins. Studies of katanin, spastin, and fidgetin in animal systems have clarified that these proteins are MT-severing. However, studies in plants have been limited to katanin p60, and little is known about spastin or fidgetin and their function in plants. I looked at plant genomes to identify MT-severing protein homologues to clarify which severing proteins exist in plants. I obtained data from a variety of eukaryotic species to look for MT-severing proteins using homology to human proteins and analyzed these protein sequences to obtain information on the evolution of MT-severing proteins in different species. I focused this analysis on MT-severing proteins in the maize and Arabidopsis thaliana genomes. I created evolutionary phylogenetic trees for katanin-p60, katanin-p80, spastin, and fidgetin using sequences from animal, plant, and fungal genomes. I focused on Arabidopsis spastin and worked to understand its functionality by identifying protein interaction partners. The yeast two-hybrid technique was used to screen an Arabidopsis cDNA library to identify putative spastin interactors. I sought to confirm the putative protein interactions by using molecular tools for protein localization such as the YFP system. …

The field of vector-borne disease research uses multidisciplinary approaches to help understand complicated interactions. This dissertation, covers three different aspects of tick-borne disease research which all focus on exploring tick-borne diseases in the non-endemic areas of Denton, County Texas and the state of Texas with a focus on Rickettsia spp. These aspects include tick sampling, testing ticks for the presence of Rickettsia spp., and creating species distribution maps of the Rickettsia spp. Rickettsia amblyommatis and tick species Amblyomma americanum.

The Science Teaching and Research (STAR) Leadership Program at Austin College was designed to intentionally include leadership development into the science curriculum and provides an opportunity to determine the effects of student leadership development on the retention of students in science, technology, engineering, and mathematics (STEM). This dissertation used a quasi-experimental design to determine: 1) if STEM retention can be explained though the inclusion of leadership development into the curriculum; 2) if there is a difference between Austin College students who choose a STEM major compared to students who do not; and 3) if there is a difference between Austin College students who complete a STEM degree compared to students who do not. Census data were collected on 2,137 students who enrolled in STEM courses beginning in the fall of 2008 through the spring of 2017, and factors affecting retention were compared across three 3-year time periods that spanned before the program was initiated through wider implementation. A logistic regression showed that there was no significant positive association between leadership development and STEM retention when taking into account other pre-college and demographic factors that have been linked to retention in the literature. However, a one-way ANOVA showed that the academic …

The City of Denton, located in a semi-arid region of Texas, has over 200 manmade ponds within its city limits. Many of these ponds, located in densely populated areas, are engineered to control storm water runoff. There is a general lack of recognition of the value these waters contribute to regional biodiversity and as greenspaces. This study, conducted in Denton, is monitoring habitat variables and macroinvertebrate diversity in a series of ponds selected to represent a gradient of urban influences. The objective of this study is to identify the variables associated with the highest diversity. Using drone imagery and a meter square box sampler, the quantitative approach allowed for delineation of three habitat types and area. The macroinvertebrates where identified to the genus level which allowed for higher resolution and resulted in stronger comparisons of the communities and conditions of the ponds. Taxa richness was positively correlated to pond size and trees along shoreline and negatively associated with average depth. Overall, submerged vegetation supported highest diversity and abundance, especially genera of Chironomidae (Diptera). Conductivity was associated with urban influences and the most urban influenced pond had the lowest taxa richness, but also reduced habitat area. Results of this study conclude …

Water quality of a stream or river is influenced by the surrounding landscape and vegetation. The Normalized Difference Vegetation Index (NDVI) is commonly used to characterize landcover and vegetation density. Benthic macroinvertebrates are ubiquitous in freshwater streams and are excellent indicators of the quality of freshwater habitats. Data from one NDVI remote sensing flight and one macroinvertebrate sampling event for eight wadeable stream study sites in the National Ecological Observatory Network (NEON) were acquired. Proportions of high, moderate, and sparse vegetation were calculated for each stream watershed using ArcGIS. Functional feeding groups and tolerance values were assigned to macroinvertebrate taxa. The Fourth-corner and RLQ methods of analysis, available in the ade4 package for R software, were used to evaluate the relationships of macroinvertebrate traits with environmental variables. Hypothesis testing using Model 6 in the ade4 package resulted in p-values of 0.066 and 0.057 for global (overall) significance. Mean NDVI values of moderately vegetated areas and proportion of sparse vegetation were found to be significant to percent shredders at alpha ≤ 0.05. Results of these methods of analysis, when combined with traditional macroinvertebrate sampling metrics, show that NDVI can be a useful, additional tool to characterize a watershed and its effects …

Using metacommunity theory, I investigated the mechanisms of meta-assemblage structure and assembly among medium- to large-bodied mammals in North Texas. Mammals were surveyed with camera-traps in thirty property units of the LBJ National Grasslands (LBJNG). In Chapter II the dispersal and environmental-control based processes in community assembly were quantified within a metacommunity context and the best-fit metacommunity structure identified. A hypothesis-driven modelling approach was used in Chapter III to determine if the patterns of species composition and site use could be explained by island biogeography theory (IBT) or the habitat amount hypothesis (HAH). Islands were defined as the LBJNG property unit or the forest patch bounded by the property unit. Forest cover was selected as the focal habitat for the HAH. Seasonal dynamics were explored in both chapters. Metacommunity structure changed with each season, resulting in quasi-nested and both quasi and idealized Gleasonian and Clementsian structures. Results indicated that the anthropogenic development is, overall, not disadvantageous for this assemblage, that community assembly receives equal contributions from spatial and environmental factors, and that the metacommunity appears to operate under the mass effects paradigm. The patterns of species composition and site use were not explained by either IBT or HAH. Likely because …

In the extensive and remote sub-Antarctic forests of South America, birds are the dominant terrestrial vertebrates. Despite considerable efforts to understand the ecology of birds breeding in these forests, our current knowledge for many species is still incomplete. During three breeding seasons (2014 – 2017), I studied the breeding ecology of the five most abundant open-cup forest-dwelling passerines in the sub-Antarctic forest of Navarino Island, Chile (55°04′S, 67°40′W). There were differences in some of the breeding strategies used by birds breeding on Navarino Island versus conspecific populations breeding at lower latitudes. Milvago chimango was the main nest predator of open-cup nesting forest passerines, and the main cause of nest failure. In addition, I found that species built their nests in sites with higher density and taller understory; however, these two factors decreased their nest survival. This mismatch could be due to a change in depredation risk on Navarino Island, and thus, passerines breeding there may be in an ecological trap. In addition, using light-level geolocators, I determined that the migratory connectivity of Elaenia albiceps is weak as a result of the large spatial spread of individuals on the wintering ground, and that the distances among individuals on the breeding grounds …

Results from the present study found for the first time that the use of bacterial strains of Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium thermophilum, and Enterococcus faecium from the commercial product PrimaLac® had the potential to act as a possible probiotic for juvenile red drum. The addition of PrimaLac® probiotics [whether as a water-soluble probiotic (WSP) or in a probiotic enhanced starter feed (PESF)] reduced mortality (%M), enhanced growth rates (MW, LT, SGR, and DGR), improved feed conversion efficiencies (FCEs), and physical condition factors in the juvenile red drum. Improvement was quantified using external morphological condition indices (MCIs) and blood physiological condition indices (PCIs). Results showed a strong positive relationship between MCIs and PCIs, which suggested that probiotics treated fish were in better health (lower MCIs) with lower fasting blood glucose and lactate levels than control fish. Addition of probiotics also resulted in improved water quality (lower nitrate, nitrite, and ammonia) in the treatment tanks compared to controls. Application of PrimaLac® probiotics on the morphology and histology of three different regions of the intestine (proximal, mid-and distal) improved intestinal length (Li), mass (Mi), and digesta mass (Md). In 5μm histological sections examined for differences among treatments (probiotics vs. controls), five variables …

Dehydroabietinal (DA), an abietane diterpenoid, was previously demonstrated to be a potent activator of systemic acquired resistance (SAR). DA also promotes flowering time in Arabidopsis thaliana by repressing expression of the flowering repressor FLOWERING LOCUS C (FLC) while simultaneously upregulating expression of FLOWERING LOCUS D (FLD), FLOWERING LOCUS VE (FVE) and RELATIVE OF EARLY FLOWERING 6 (REF6), a set of flowering time promoters. To further understand the mechanism underlying signaling by abietane diterpenoids, Arabidopsis mutants exhibiting reduced responsiveness to abietane diterpenoids were identified. One such mutant plant, ems2/7, exhibited SAR-deficiency and delayed flowering, which were found to be associated with two independent, but linked loci. The gene responsible for the SAR defect in ems2/7 was identified as DEFECTIVE IN SYSTEMIC DEFENSE INDUCED BY ABIETANE DITERPENOID 1 (DSA1). Similar to the missense mutant dsa1-1 identified in the mutant screen, the T-DNA insertion bearing null allele dsa1-2 exhibited SAR deficiency that could be complemented by a genomic copy of DSA1. The gene responsible for the delayed flowering phenotype of ems2/7 remains to be identified. DSA1 encodes a protein that is homologous to human protein O-fucosyltransferase 2. DSA1 is required for long-distance transport of the SAR signal. It is hypothesized that DSA1 is …

Ecosystem services are the varied goods and benefits provided by ecosystems that make human life possible. This concept has fostered scientific explorations of the services that nature provides to people with the goal of sustaining those services for future generations. As the world becomes increasingly urban, ecosystems are reshaped, and services are degraded. Provisioning and regulating ecosystem services, landscape planning, decision making, and agricultural systems and technologies play a distinctive role in feeding and sustaining the expanding urban population. Hence, the integrated assessment of these coupled components is necessary to understand food security and sustainable development. Nevertheless, frameworks that incorporate ecosystem services, urbanization, and human wellbeing are still scarce due to several conceptual and methodological gaps that challenge this assessment. As a consequence, these frameworks are not operationalized, and ecosystem services rarely receive proper attention in decision making. This dissertation seeks to improve our understanding of the role of ecosystem services at the landscape level and provides an approach for operationalizing decisions that affect sustainable practices and human wellbeing.

Pseudomonas fluorescens NCIMB 11764 (Pf11764) is one of a group of bacteria known as cyanotrophs that exhibit the unique ability to grow on toxic cyanide as the sole nitrogen source. This ability has previously been genetically linked to a conserved cluster of seven genes (Nit1C), the signature gene (nitC) coding for a nitrilase enzyme. Nitrilases convert nitriles to ammonia and a carboxylic acid. Still, for the Pf11764 NitC enzyme (Nit11764), no in vivo substrate has been identified, and the basis of the enzyme's requirement for cyanide growth has remained unclear. Therefore, the gene was cloned and the enzyme was characterized with respect to its structure and function. These efforts resulted in the unique discovery that, aside from its nitrilase activity, Nit11764 exhibits nuclease activity towards both DNA and RNA. This ability is consistent with computer analysis of the protein providing evidence of a preponderance of amino acids with a high probability for RNA binding. A Nit11764 knock-out mutant was shown to exhibit a higher sensitivity to both cyanide (KCN) and mitomycin C, both known to induce chromosomal damage. Thus, the overall conclusion is that Nit11764, and likely the entire Nit1C gene cluster, functions as a possible repair mechanism for overcoming …