Digital Commons Network^™

The Effects Of Floral And Social Information On Bumblebee Forager Learning And Memory, Avery Hume Baker

Theses

Bumblebees rely on information gathered from their environment to make the best choices they can when foraging for pollen and nectar. The type of information gathered should influence how a bee learns and remembers it, but other factors such as the size of the bee’s brain may also play a role in the learning and remembering process. While social information learned from other organisms and information gathered directly from flowers can each be used alone to improve both the efficiency with which a bee learns to forage from a flower and how accurately and how long the bee remembers these …

Taxonomic Revision And Morphometric Analysis Of Selected Anthurium (Araceae) Species From Bolivia And Peru, Daniel M. Tarazona Ocana

Theses

The genus Anthurium (Araceae) consists of around 1,200 species distributed in the Neotropics, particularly in Central and South America. The montane forests in the eastern flank of the Andes, ranging from northern Ecuador to central Bolivia; hereafter, the East Andes Gradient region, are particularly rich in terms of species diversity, and include an understudied group of Anthurium species endemic to the region. Within this group of species, some taxa are difficult to distinguish from each other mainly due to the lack of identification keys, incomplete species descriptions and unknown synonyms. In this study, a combination of traditional taxonomic techniques and …

Maternal Effects On Growth Parameters Of Chloris Gayana Under Co2 Enrichment, Ahmed Adnan Mohammed Mashli

Theses

Rhodes grass, Chloris gayana, is commonly used forage plant for grazers, livestock, and cattle. It significantly improves soil fertility and its overall structure by preventing nematode flourishment in soil. It is also used as a cover crop to upgrade soil health by reducing soil erosion and increasing water availability. The present study assessed the effects of CO₂ on the growth, development and maternal effects of C. gayana. The experimental setup was made in such a way that the potential impacts of CO₂ can be measured on the eco-physiological growth of C. gayana by studying successive generations. Generation 1 …

Effect Of Carnosol On G Protein-Coupled Receptor Signaling In Cancer Cells, Laith Jehad Ahmad Abudawood

Theses

Carnosol is a plant polyphenol compound known for its beneficial properties against human diseases such as cancer and diabetes. However, the exact molecular and cellular mechanisms involved, and its molecular targets are not fully known. Carnosol was shown to bind and to modulate specific intracellular signaling proteins in cancer cell lines. In this study, we hypothesized that carnosol may pharmacologically target specific cell surface receptors including G Protein-Coupled Receptors (GPCRs) and Receptor Tyrosine Kinase (RTKs). Therefore, we tested the pharmacological effect of carnosol on the following receptors: Insulin Receptor (IR), Chemokine CXCL12 Receptor (CXCR4), Angiotensin II (AngII) Receptor (AT1R), Glucagon-Like …

Distribution Of Erm Proteins In The Stomach Mucosa Of Normal And Diabetic Rats, Asmaa Salem Al Sereidi

Theses

Diabetes mellitus (DM), or simply diabetes, refers to a group of metabolic disorders that include a variety of diseases that disrupt our body's metabolism. The long-term uncontrolled disease can lead to stomach complications such as gastroparesis, as well as disruption in several proteins, such as ERM (Ezrin, radixin, moesin) proteins. ERM proteins are three proteins that are structurally and functionally related. ERM proteins have molecular masses of 82, 80, and 75 kDa, respectively. Ezrin is highly expressed in the stomach, especially in parietal cells that secrete gastric acid. ERM proteins function as scaffolding proteins in lipid rafts and granule trafficking …

Heterodimerization Between Chemokine Receptors Cxcr4 And Ccr7 And Its Role In Cancer, Maryam Naveed Muhammad Tariq

Theses

In physiology, the functional and physical interactions between cell surface receptors for signal molecules such as hormones, neurotransmitters, and cytokines, provides an important mechanism of diversity and regulation of signal transduction. Therefore, investigating the functional interactions between these receptors is of great importance for understanding their role in physiology and pathophysiology with potential application in drug discovery. In this context, numerous evidences support the implication of two chemokine receptors, CXCR4 and CCR7, in many cancer types. In this study, we hypothesized that the functional, and perhaps the physical interaction, occurring between CXCR4 and CCR7 may constitute one of the key …

The Effect Of Licogliflozin (Sglt1/2 Inhibitor) On Diabetes And Cardiac Complications, Alanoud Gharib Alblooshi

Theses

Diabetes mellitus (DM) is a chronic endocrine disease affecting millions of people worldwide. In spite of the advances made in the management of DM, poor glycemic control and diabetes complications are still very common. There is a continuous search for new and more effective drugs to treat DM. One of the drugs currently in clinical trials for the treatment of DM is licogliflozin (LIK066), a dual SGLT1/2 inhibitor, which can be used to treat obesity and diabetes. LIK066 inhibits glucose reabsorption in the kidney and small intestine, thereby reducing hyperglycemia. This study aims to investigate the efficacy of licogliflozin on …

Lactic Acid Bacteria Isolated From Fresh Vegetable Products: Potential Probiotic And Postbiotic Characteristics Including Immunomodulatory Effects, Fatima Khaled Alameri

Theses

The ability to perform effectively in the gastrointestinal system (GIT) is one of the most significant criteria for selecting the best probiotic bacteria. Thus, the present study aimed to investigate the potential probiotic characteristics of some selected lactic acid bacteria (LAB) isolated from vegetable products. Probiotic characteristics included tolerance to acid and bile, cholesterol removing ability, bile salt hydrolysis, resistance against lysozyme and antibiotics, production of exopolysaccharides (EPS), antimicrobial and hemolytic activities, and cell surface characteristics (auto-aggregation, co-aggregation, and hydrophobicity). Out of 46 isolates, 17 isolates that exhibited remarkable survivability under gastrointestinal conditions were selected for further analysis. Almost all …

Screening For Endophytic Actinobacteria To Enhance Growth And Salinity Tolerance Of Tomato Plants In The United Arab, Amira Hamdy Hassan

Theses

Salinity is one of the most decisive environmental factors limiting the productivity of crop plants, mainly in arid and semi-arid regions. An eco-friendly technology can be used to boost crop production in saline areas by using plant growth-bacteria. Endophytic actinobacteria that produce the enzyme 1-Aminocyclopropane-1-Carboxylic acid (ACC) Deaminase (ACCD) can modulate the levels of Ethylene (ET) in plants to reduce the effect of abiotic stresses including high salt stress. The main objectives of this study were to: (1) Evaluate endophytic actinobacterial isolates from healthy tomato plants cultivated in the UAE that are capable of producing ACCD in vitro; (2) …

Correlation Of Gut Alteration With The Progression Of Experimental Autoimmune Encephalomyelitis (Eae) In C57bl/6 Mice, Al Anood Ahmed Al Naqbi

Theses

Background: Experimental autoimmune encephalomyelitis (EAE) is the mouse disease model of multiple sclerosis (MS), a chronic autoimmune disease targeting the central nervous system (CNS) resulting in neuroinflammation, neuroaxonal degeneration, and demyelination. Autoreactive CD4⁺ T cells are known for their role in the pathogenesis of MS. CD8⁺ T cells and NK cells were also found to be associated with the disease.

Aim: There is a limited number of studies investigating the link between gut alterations and immune cells in the gut influencing the outcome of the disease since the vast majority of MS patients experience gastrointestinal (GI) problems. Here, …

Development Of Phage Therapy Strategies Against Gram-Positive Bacterial Pathogens, Sara Arroyo Moreno

Theses

Bacterial resistance to conventional antibiotics has become an urgent healthcare issue worldwide. In this light, a renewed interest has emerged for therapy with bacteriophages (phages), which are viruses that can specifically infect bacteria. These viruses encode different proteins that degrade specific bonds within the bacterial cell wall, both to inject their genomic material into the bacterial cells and to release the viral progeny: virion-associated hydrolases and endolysins, respectively. Elimination of Gram-positive pathogens with recombinant versions of phage enzymes represents a promising alternative to classical antibiotics. In this thesis, different phage therapy strategies involving either whole phages or the use of …

Distribution Of Carrion-Associated Beetles And Their Phoretic Mites Along An Urban-Rural Gradient In Northeast Alabama, Kennedy Norris

Theses

Global insect decline has been linked to urbanization, most notably by habitat fragmentation. These insects perform important ecological functions such as pollination, managing pests, and decomposing carrion to recycle nutrients back into the environment. Despite the importance of nutrient recycling behavior displayed by carrion-associated beetles, little research has been done on them in the southeastern US. Previous studies have found a relationship between urbanization, less favorable environmental conditions, carrion availability, and decreased insect diversity. However, no studies have been conducted in the southeastern United States on the relationship of these beetles to their environment despite having the highest rates of …

Critical Corridor: Survey Of Predator Occurrence And Habitat Use In A Threatened Rainforest Protected Area: Comatsa-Sud And Marojejy National Park, Madagascar, Patrick H. Ross

Theses

Madagascar is a nation praised for its floral and faunal endemism and biodiversity. Among the island nation’s most emblematic fauna are its native mammalian carnivores; they are members of the threatened and endemic Eupleridae family. The Corridor of Marojejy – Anjanaharibe Sud – Tsaratanana (COMATSA) is a system of forest protected areas in which three large protected areas are connected in northern Madagascar: Tsaratanana Reserve, Anjanaharibe Sud Special Reserve and Marojejy National Park which is also a UNESCO World Heritage site. COMATSA is a newly protected and currently threatened corridor system that lacks detailed surveys and assessments of its native …

A Study On Plant-Derived Small Proteins And Peptides With Antiyeast Activity And Preliminary Investigations In Food Materials, Giulia Mignone

Theses

The discovery of novel antimicrobial molecules would benefit considerably different biotechnological fields, including medicine, agriculture and the food industry, on which this thesis work focuses. Specifically, here are presented fundamental studies on plant-derived antimicrobial proteins for the reduction of food spoilage caused by yeast microorganisms. Small proteins and peptides from the plant innate immune system possess several characteristics which could make them ideal candidates for a novel and natural antispoilage agent. The first Chapter reviews proteins families associated with the plant innate immune system that exhibit antiyeast activity and low molecular weight (<30 kDa), focusing on their structure and antiyeast mode of action. Chapter 2 investigates two peptides, Pn-AMP1 and Pn-AMP2 belonging to the hevein-type peptides family; peptides were synthetically generated using their native amino acid sequence. Synthetic Pn-AMP1 showed fast action activity against common food spoilage yeasts, it resulted potentially safe for consumption, and it was successfully incorporated in UHT milk and Fanta Orange, where it contained the growth of Kluyveromyces lactis and Zygosaccharomyces bailii, respectively. A different family of antimicrobial plant proteins (2S albumins) was studied in Chapters 3, 4, 5 and 6. Chapter 3 describes the selective extraction of an antiyeast protein (labelled WMS1 in this thesis work) of ~14 kDa from white mustard (Brassica hirta) seeds. The protein was purified in a relatively high yield, using a simple protocol that included only one chromatographic method step. In Chapter 4, bioinformatics tools and wet-lab techniques are used to study the structure and classify the antiyeast protein. The WMS1 antiyeast protein was identified as an isoform of the Napin protein Allergen Sin a 1 belonging to the 2S albumins family, characterised by high structural stability which donates to the protein resistance heat treatment and proteolytic degradation. Chapter 5 describes the antimicrobial spectrum of WMS1 , its antiyeast mechanism of action and its validity as preservative agent. Although WMS1 resulted potentially safe for consumption and inhibited the growth of Z. bailii in several beverage systems, its biotechnological potential is limited by its allergic properties. In Chapter 6, the protein WMS1 was cloned in a pET28a-MBP vector and expressed in an E. coli BL21 system. Interestedly, recombinant WMS1 and native WMS1 showed similar activity against the yeast Z. bailii. Thesis abstract 2 Chapter 7 includes a protocol for the rational design of ultra-short antimicrobial peptides. Since ultra-short antimicrobial sequences can be found within the sequence of any larger protein, the protocol was applied using WMS1 primary sequence, and seven ultra-short SinA-AMPs were chemically generated. Among the various SinA-AMPs, the peptide labelled SinA-pepIII had in vitro activity against several common yeast spoilage strains via membrane permeabilisation and it could be employed as a food preservative as it was pH- and heat- stable, potentially safe in terms of human consumption and it prevented the growth of Z. bailii in cranberry juice. The results obtained in this work offer new perspectives in the research for novel and clean-label food preservatives to fight the food waste phenomenon.

Impact Of Saline Water Irrigation On Date Palm (Phoenix Dactylifera) Associated Bulk Soil Bacterial Communities In Oases Agroecosystem Of Uae, Fardous Abdi Ibrahim Jibar Alhashmi

Theses

Irrigation of date palm (Phoenix dactylifera) with saline groundwater is routinely practiced in the arid agroecosystems of United Arab Emirates (UAE), due to freshwater scarcity. Saline groundwater irrigation is known to deposit salts in the top layers of soil and increase soil salinization. However, how increasing soil salinization affects the belowground bacterial communities, is not well investigated. Soil samples were collected from 14 different date farms where irrigation water source was either non–saline water or saline groundwater. Soil bacterial communities were identified using 16S rRNA gene metabarcoding. The results showed that bacterial diversity (including Shannon diversity, richness, and …

The Use Of Actinobacteria To Improve The Efficacy Of Phytoremediation Of Heavy Metal-Polluted Soils In The United Arab Emirates, Fatima Abdulmoneim Hussain

Theses

In an effort to gain the advantages provided by actinobacterial enzyme (1- aminocyclopropane-1-carboxylic acid) (ACC) deaminase (ACCD) in the phytoremediation of heavy metals from the environment, the ability of native actinobacteria with ACC deaminase activity to promote the growth of Bermuda grass (Cynodon dactylon L.) in soils contaminated with nickel nitrate was evaluated under greenhouse conditions. This enzyme hydrolyzes (ACC), the immediate biosynthetic precursors of the hormone ethylene (ET) in plant tissues to ammonia and α keto-butyrate. The main objectives of this study were: (1) Isolating beneficial native heavy metal-tolerant actinobacteria from the United Arab Emirates (UAE) contaminated soil capable …

Factors Affecting The Antibacterial Activity Of Cefiderocol On Klebsiella Pneumoniae With Diverse Characteristics, Lana Jamal Rashed Daoud

Theses

Antimicrobial resistance (AMR) is a growing serious threat that poses a burden on the healthcare system. Spread of AMR bacteria limits treatment options; thus, new antimicrobial agents are required. Cefiderocol (CFDC) is a novel siderophore cephalosporin, approved by the FDA in 2019 for use in treating infections caused by multi-drug resistant (MDR) pathogens; but it is not yet in clinical use in the UAE. CFDC is equipped with stabilizers against β-lactamases as well as a siderophore side chain that allows it to penetrate the outer membrane of bacteria through the iron uptake pathways. The aim of this study is to …

Distribution Modelling Of Socotra Cormorant Using Maxent, Areej Mustafa Jaradat

Theses

This thesis is concerned with species distribution modeling of the Socotra Cormorant (Phalacrocorax nigrogularis), a regionally endemic seabird to the Arabian Gulf, the Arabian Sea, and the Gulf of Aden. Socotra Cormorants are important for the marine ecosystem as they apply top-down control and maintain the balance between trophic levels. They also contribute to the cycling of nutrients significantly. The bird is categorized as vulnerable by the IUCN. Large portions of their suitable habitat are disturbed or degraded due to oil exploration and coastal development. The seabird is poorly studied in every ecological aspect. The main objective of …

Optimization Of Palmitic Acid Production In Chloroidium Sp. Utex 3007 As A Sustainable Source Of Palm Oil Alternative, Amnah Salem Alzahmi

Theses

The increase in palm oil consumption and production has resulted in removing up to 90% of trees in some tropical forests. The green microalgae Chloroidium sp. UTEX 3007 can be an alternative sustainable source of palm oil due to its high palmitic acid content. The objective of this study was to generate a mutant Chloroidium population that is capable of producing and accumulating elevated levels of palmitic acid and to characterize the obtained populations’ lipid contents. The palmitic acid production optimization in Chloroidium sp. UTEX 3007 was conducted via a workflow of ultraviolet (UV) mutagenesis and sorting of high-lipid producing …

Regulation Of Activity Patterns In Astyanax Mexicanus Cavefish, Udodirim Nwosu

Theses

Organisms commonly modulate their behavioral activity in relation to the 24-hour solar cycle. This modulation of behavior is driven by a combination of responses to external cues in the environment, such as light/dark visual signals, and internal pattern generators that can persist in the absence of external cues. However, there are animals that live in caves or in the deep sea that are isolated from solar circadian cues. How these animals regulate their behavioral activity in relation to external and internal rhythms is an open question in neuroscience that may help us to understand the mechanisms that other animals, including …

A Detailed Parameter Study Into The Dermal Absorption Of Chemical Warfare Agents And The Effects Of Pharmacokinetics, Koko Lear

Theses

Chemical warfare agents (CWAs) are substances of varying toxicity profiles. These chemicals exhibit complex dynamics and pose a serious health risk when released into the environment. A mathematical model based on Fick’s second law of diffusion was developed to comprehend how these compounds were absorbed into the skin. The analysis applied to both small and large doses and, successfully, predicted experimental results. This work also includes the effects of CWA physicochemical properties on evaporation and dermal absorption through the stratum corneum. A sensitivity analysis was conducted to assess the impacts of small variations in the initial dose, environmental conditions, and …

Distribution Patterns Of The Invasive Mussel Arcuatula Senhousia In Mission Bay, San Diego, California: Effects Of Sediment Grain Size And Byssus Thread Production On Predation, Samantha Ahlman

Theses

The ability of bivalves to avoid predation by using defensive behaviors such as burrowing and byssus production may vary depending on the sediment characteristics of a given habitat. The varying sediment characteristics that change with water velocity within estuaries may influence the distribution of bivalves and limit them to areas that optimize their ability to defend against predators. We examined the distribution patterns of the invasive Asian date mussel Arcuatula senhousia relative to the sediment grain size distribution in Mission Bay, an urban estuary located in San Diego, California, USA. Mussels and sediment were collected using an Ekman grab at …

The Effect Of Different Feeding Regimes On Recent Nutritional And Growth Measurements In Juvenile California Killifish (Fundulus Parvipinnis), Emily Parks

Theses

Gaining a deeper understanding of in-situ growth approximations for juvenile fishes is one way to understand how food consumption may affect fish growth. If variations in growth rate are strongly mirrored by past food status, then the condition (degree of well-being) of fish can be potentially used as a reference for relative prey availability. Furthermore, confirming that there is a positive relationship between food availability and fish growth rate is a critical first step to deepen our understanding of growth rate variation as well as examining if growth can be a proxy for habitat quality.

The California killifish (Fundulus …

Mechanistic Insights On The Role Of Ambrisentan, An Endothelin Type-A Receptor Antagonist, In Breast Cancer, Ruba Saleem Lutfi Amer

Theses

The activation of the endothelin receptor type A (ETAR) by its ligand endothelin-1 (ET-1) is well known for its role in vasoconstriction. Interestingly, ET-1 and ETAR are over-expressed in various human tumours, including breast cancer. Several studies described the important role of ETAR in cancer progression and metastasis. The extensive network of interactions that exist between the ET-1 axis and other signalling pathways can trigger autocrine and paracrine signalling that modulates different tumorigenesis processes, such as cellular proliferation and survival, epithelial-to-mesenchymal transition (EMT) and chemoresistance. The main objective of this study was to investigate the antitumor effects of Ambrisentan, a …

Movement Patterns Of The Shovelnose Guitarfish (Pseudobatos Productus) And California Bat Ray (Myliobatis Californica) In The Southern California Bight, Annabel Gong

Theses

While the movement patterns of large elasmobranch species have been studied extensively, those of smaller, mesopredatory species remain understudied. The shovelnose guitarfish (Pseudobatos productus) and the California bat ray (Myliobatis californica) are among the least studied elasmobranchs in the Southern California Bight. This study quantified the broad- and fine-scale movement patterns of these species using passive acoustic telemetry. Twelve guitarfish were surgically implanted with coded acoustic transmitters at a known aggregation site off La Jolla (San Diego County), California, USA and tracked for 849.5 days each, on average. Six bat rays were also implanted here and tracked for …

Molecular Evidence Of Cryptic Hybridization In The Japanese Nezasa Bamboos (Pleioblastus Section Nezasa), Ryan Long

Theses

The genus Pleioblastus is a complex group of Southeast Asian temperate bamboos with 7-21 species, depending on taxonomic authority. This study tests the hypothesis that taxonomic complexity in this group is due in part to hybridization and subsequent backcrossing in natural populations, resulting in a reticulate evolutionary history and a contemporary species assemblage that includes cryptic hybrids. This hypothesis is supported by recent research on the temperate bamboos that revealed intergeneric hybrids involving Pleioblastus and other genera of temperate bamboos (Triplett and Clark, 2021). The objective of the current study was to use data from Amplified Fragment Length Polymorphism (AFLP) …

Behavioral Choices Of Apple Snails, Pomacea Maculata, Under Varied Chemical Landscapes, Andrea Adams

Theses

Habitat choice is a critical behavior for organisms to successfully survive and reproduce. These choices are dictated by available environmental information about potential predation risks or food patches that form the organism’s sensory landscape. This study specifically focused on the behavioral choices of two invasive apple snail (Pomacea maculata) populations exposed to varying predation threats. We collected snails from Florida and Alabama which were used in laboratory experiments with varied sensory landscapes. Trials consisted of controls with no cues (FL: n = 7, AL: n= 7), an attractive treatment with introduced food cues (FL: n = 4, AL: …

Comparative Modeling And Evolutionary Comparison Of Serine Protease, A Timber Rattlesnake Venom Protein, Qawer Ayaz

Theses

The aim of this study is to create a homology model of VG35 serine protease and evaluate the evolutionary comparison of secondary structure on basis of protein model using YASARA. This method was furthermore used to predict the potential epitopes which can help in the investigation of future studies.

The VG35 was used to run a BLAST search which gave most resembled serine protease of different species which was then translated and modeled in YASARA. The modeled protein data was then used to determine the secondary structure. This was then used for evolutionary comparison of all proteins to VG35. Then …

Cryptic Hybridization In The Temperate Bamboos: Is Pleioblastus Simonii A Species Of Hybrid Origin?, Morgan Brown

Theses

Japanese river bamboo (Pleioblastus simonii, ‘medake,’‘kawadake’) is an ecologically important species of temperate bamboo native to Japan. This species is widely known and historically important in Japanese rural farm life. Based on morphological data, Japanese river bamboo is classified in Pleioblastus section Medakea (Poaceae: Bambusoideae) along with five other Japanese species, which are collectively considered to represent a phylogenetically distinct lineage. However, recent studies suggest that Japanese river bamboo may have arisen as a result of previously undetected hybridization (i.e., cryptic hybridization), while also calling into question the diversity of section Medakea. The role of hybridization in natural plant populations …

A Computational Assessment Of The Allosteric Modulation Of Gabaa Receptor, Abdel Rahman Atef Aly

Theses

γ-aminobutyric acid (GABA) type A receptor (GABA_AR) is a pentameric ligand gated ion channel and a member of the Cys-loop superfamily. It is targeted by several clinically significant allosteric modulators. The role of individual subunits of the receptor has been very extensively studied. However, the exact molecular pathway upon which the receptor is activated remains elusive. The main objective of this study was to probe the molecular activation pathway for the orthosteric GABA and to understand how two of the most well-established positive (PAM) and negative (NAM) allosteric modulators tend to modulate the receptor. Three independent long scale …