Life Sciences Commons^™

Effect Of Feed Supplementation With Effective Microorganisms (Em) Bokashi Onhepatopancreas And Gut Histology, Growth Performance, And Survival Rate Of Freshwatercrayfish Pontastacus Leptodactylus (Eschscholtz, 1823), Hasan Batuhan Emre Özdoğan, Seval Bahadir Koca, Özlem Özmen, Kami̇l Eki̇nci̇, Emi̇ne Eki̇nci̇, Habi̇l Uğur Koca, Nalan Özgür Yi̇ği̇t

Turkish Journal of Veterinary & Animal Sciences

A sixty-day feeding trial was conducted to investigate the effect of dietary effective microorganisms (EM) Bokashi on organ histology, growth performance, and survival rate of freshwater crayfish Pontastacus leptodactylus (Eschscholtz, 1823). Bokashi serum and powder consisted of two major microorganisms as Bacillus amyloliquefaciens spp. plantarum and Lactobacillus plantarum. Four treatment groups were established in control (without bokashi), bokashi powder 1% and 5% supplemented to diets. Bokashi serum was added at a ratio of 0.01% (v/v) of the total volume of the tank water once a week into which there was a constant flow of fresh water at a flow rate …

Comparison Of Low-Level Laser And Dimethyl Sulfoxide Applications For The Treatment Oftendon Injury In Rabbits, Kardelen Ceydeli̇oğlu, Gülteki̇n Atalan, Duygu Yaman Gram, Gökçen Perk

Turkish Journal of Veterinary & Animal Sciences

The aim of this study was to investigate and compare the effects of low-level laser therapy (LLLT) and dimethyl sulfoxide (DMSO) on tendon healing in rabbits. A total of 30 adult healthy New Zealand rabbits were used for this study. The rabbits were randomly allocated into 3 groups containing an equal animal number. The experimental tenotomy of the Achilles tendons was created on longitudinal aspect with 10 mm in length. During the postoperative 21-day of period, rabbits in Group I were exposed to laser beam at a rate of 10.8 J/cm$^{2}$ in 5 cm$^{2}$ area for 4 min. In the …

Comparison Of M, Mm And Lts Estimators In Linear Regression In The Presence Of Outlier, Cem Tirink, Hasan Önder

Turkish Journal of Veterinary & Animal Sciences

In this study, it was aimed to evaluate the performance of different estimators that will be used in regression analysis, which is one of the multivariate statistical methods in the presence of outliers in the data set. Sixth month live weight was estimated with various body measurements for Saanen kids taken from a private farm. In the data set, the use and performance of robust estimators were evaluated because the least squares method did not provide reliable results in the case of outliers. M (for Huber and Tukey bisquare) estimator, MM estimator and LTS estimator were used as robust used …

Determining The Genetic Diversity Of Silkworm Lines In Turkey, Ezgi̇ Odabaş, İbrahi̇m Cemal

Turkish Journal of Veterinary & Animal Sciences

Studies involving molecular genetic characterization of silkworms are quite limited. Therefore, with this study, pure and hybrid silkworm lines raised in Turkey was characterized for the first time by microsatellite DNA markers. Samples were collected from 7 different silkworm lines, of which the pure lines were obtained from the Provincial Directorate of Agriculture and Forestry in Bursa and the hybrid ones from Silkworm Cocoon Association of Turkey (Kozabirlik). DNA samples were extracted from silkworm eggs. Genotyping was done by combining a total of 16 microsatellite markers in a single multiplex. Two hundred and eighty-one alleles were observed for 16 microsatellite …

Investigating Genetic Diversity Of Indonesian Native Cattle Breeds Using Mitochondrialdna 16s Rrna Gene, Restu Misrianti, Sony Hartono Wijaya, Cece Sumantri, Jakaria Jakaria

Turkish Journal of Veterinary & Animal Sciences

This study aimed to estimate the genetic diversity and phylogenetic relationships of Indonesian native and local cattle breeds using 16S rRNA mitochondrial DNA. The study analyzed 93 DNA samples from six cattle breeds. The polymerase chain reaction was conducted using two primer pairs to sequence the complete 16S rRNA gene. The number of the polymorphic site (S), pairwise nucleotide differences (K), haplotype diversity (Hd), and nucleotide diversity (?) were estimated using DnaSP 6 software. PopART v. 1.7 software was employed for the median-joining network analysis, while a neighbor-joining tree was reconstructed based on the Kimura 2-parameter model using MEGA X …

Forage Turnip (Brassica Rapa) Harvested In Different Phases Of Vegetative Stage Andensiled With The Additives Of Molasses And Barley And The Effects Of Additives On Silagequality, In Vitro Digestibility, And Energy Content, Serhat Yildiz, Suphi̇ Deni̇z, Fatma Özkan, Çağri Kale

Turkish Journal of Veterinary & Animal Sciences

This study was conducted to determine the silage quality, in vitro digestibility and energy content of forage turnip (Brassica rapa) ensiled with molasses or ground barley. Forage turnip was harvested at three different stages: the beginning, middle and end of the flowering period, and it was ensiled with no additive (control), 5% molasses or 4% ground barley. In the trial, pH, nutrient contents, ammonia nitrogen (NH$_{3}$-N) contents, volatile fatty acid (VFA) contents, Fleig scores, in vitro digestibility and energy content were determined. It was observed that the effect of the vegetative stage on the difference between the groups was significant …

Monensin Induces Apoptosis In The Liver Tissue And Primary Hepatocytes Of Chicks, Muhammet Yasi̇n Tekeli̇, Murat Kanbur

Turkish Journal of Veterinary & Animal Sciences

In this study, monensin (MON) was investigated for its apoptotic and genotoxic effects on chick liver tissue and cytotoxic and apoptotic effects on chick primary hepatocytes isolated from perfused liver tissue. Western blotting and real-time PCR (qPCR) were used to determine the apoptotic effect on primary hepatocytes and liver tissue, and the comet assay was used to determine the genotoxic effect on liver tissue. MON decreased cell viability in primary hepatocytes with increasing concentrations. When administered at concentrations of 1 and 10 μM, MON increased the levels of apoptotic p53, caspase-3, and caspase-9, and downregulated the expression of the antiapoptotic …

Do Horses Learn How To Reach For Feed Depending On The Time Of Day?, Agnieszka Ziemianska, Maciej Trojan, Konrad Bazewicz, Justyna Wojtas, Tomasz Próchniak, Iwona Rozempolska-Rucinska

Turkish Journal of Veterinary & Animal Sciences

The aim of the study was to assess the ability of horses to learn how to open feeder boxes in a direction associated with the time of day. The study involved 10 horses. The first stage of the study consisted in learning how to complete the task. The second stage involved the test and was followed by a control stage. The results indicated the highest number of failed attempts in the leftward movement test. The mean time required by the horses to complete the task of the leftward opening (10.27 s) was twofold longer than in the rightward direction test …

Activities And Mechanisms Of Oregano, Marjoram And Rosemary Essential Oils Against Malassezia Pachydermatitis Isolates From Canine And Feline Otitis, Stefanie Bressan Waller, Marcia Kutscher Ripoll, Anna Luiza Silva, Emanoele Figueiredo Serra, Tábata Pereira Dias, Vittória Bassi Das Neves, Luciéle Pereira De Melo, Patrícia Lindemann, Otávia De Almeida Martins, Angelita Dos Reis Gomes, Renata Osório De Faria, Mário Carlos Araújo Meireles, João Roberto Braga De Mello, Marlete Brum Cleff

Turkish Journal of Veterinary & Animal Sciences

Malassezia pachydermatis is an opportunistic yeast found in the ear canal of small animals; however, the current azole-based therapy applied to it has failed to achieve clinical success due to the antifungal resistance. This issue has encouraged the studies in natural products, such as Origanum vulgare (oregano), Origanum majorana (marjoram) and Rosmarinus officinalis (rosemary) essential oils, although their mechanism of action remains unclear. Malassezia pachydermatis specimens deriving from otitis cases in dogs (n = 22) and cats (n = 2) were subjected to CLSI M27-A3. Sorbitol protection and ergosterol effect were analyzed to investigate their mechanism of action. Fungistatic (MIC) …

The Effect Of Osteosubstitution By Platelet-Rich Autofibrin And Hydroxyapatite Ceramic With Ss-Tricalcium Phosphate On Biochemical Parameters Of Blood In Rabbits, Svitlana Shevchenko, Mykhailo Rublenko

Turkish Journal of Veterinary & Animal Sciences

The paper presents the results of a rabbit blood biochemical study after the substitution of simulated defects in spongy and compact bone tissue by platelet-rich fibrin and its combination with hydroxyapatite granules with ß-tricalcium phosphate. The aim of the work is to establish the biochemical features of reparative osteogenesis in the time of osteosubstitution by platelet-enriched fibrin and its combination with hydroxyapatite and ß-tricalcium phosphate. Bone defects (d = 3 mm) were modeled in rabbits from control and experimental groups (n = 12) under general anaesthesia. In the control group, a replacement was performed with autologous fibrin enriched with platelets …

The Effect Of Microbial Inoculants And Molasses On Quality And In Vitro Digestibility Of Silages Prepared With Different Proportions Of Ryegrass And Hungarian Vetch, Gökhan Şen, Taşkin Erol, Kami̇l Kara, Mehmet Demi̇rci̇, Mehmet Aki̇f Karsli

Turkish Journal of Veterinary & Animal Sciences

In this study, it was aimed to determine the effect of microbial inoculants and molasses on the quality and in vitro digestibility of the silages ensiled from the cultivation of different proportions of ryegrass-Hungarian vetch mixtures grown in Central Anatolian conditions. For this purpose, 5% molasses and 10 g/ton (1.25 × 10$^{11}$ CFU/g) inoculant were added to silages of ryegrass (Lolium multiflorum L.) containing 20%, 40%, 60%, and 80% Hungarian vetch (Vicia pannonica L.), under laboratory conditions. The prepared silages were opened at the end of 60 days and their physical analysis, chemical contents, fermentation parameters, in vitro digestibilities using …

Effects Of Pueraria Lobata Leaf Powder As A Feed Additive On The Immune System And Growth Performance Of Broiler Chickens, Jianping Gong, Dong Wu, Mengchu Li, Xiaoyu Qiu, Ying Jiang, Jie Zhang, Wenping Huang

Turkish Journal of Veterinary & Animal Sciences

The present research assessed the effect of different levels of Pueraria lobate leaf (PLL) on growth performance, immunity, antioxidant capacity, and blood index in broiler feed. A total of 384 at 21 days old chicks were assigned to 1 of 4 dietary treatments to examine the benefits of basal diet, basal diet +1% PLL, basal diet +2% PLL and basal diet +3% PLL. The trial was divided into 2 time periods, including starter from days 21-49 and finisher from days 50-70. The addition of 2% and 3% PLL powder to diets increased total protein content, triglycerides, albumin, and low-density lipoprotein …

Crude Glycerin And Waste Sesame Seed In The Diets Of Growing Lambs: Impacts On Growth Performance, Nutrient Digestibility, Ruminal Fermentation, Carcass Characteristics, And Meat Fatty Acid Profile, Bora Bölükbaş, İsmai̇l Kaya

Turkish Journal of Veterinary & Animal Sciences

The aim of the present study was to investigate the effects of a combination of crude glycerin and waste sesame seed on the growth performance, rumen fermentation, carcass characteristics, and meat fatty acid profile of lambs. Twenty-four male Karayaka lambs with initial body weights of 26.5 ± 0.53 kg were randomly divided into four groups and raised in individual pens. For 70 days, lambs were fed ad libitum the one of four concentrates: concentrate without CG and WSS (control), concentrate with 10% CG (G), concentrate with 10% WSS (W), and concentrate with 5% CG and 5% WSS (GW). All diets …

High Sensitivity Cardiac Troponin T (Hs-Ctnt) And I (Hs-Ctni) Levels In Dogs With Dirofilaria Immitis, Cemaletti̇n Ayvazoğlu, Şemi̇stan Kiziltepe, Ümi̇t Yaşar, Zehra Gül Yaşar, Pinar Demi̇r, Abuzer Acar

Turkish Journal of Veterinary & Animal Sciences

Dirofilaria immitis (D. immitis); is a parasitic zoonosis with a prevalence of 53.8%, whose intermediate host is mosquitoes (Anopheles, Aedes, Culex, Taeniorhychus, Mansonia and Armigenes), final hosts are carnivores (dog, cat, fox, etc.) and humans. The causative agent settles in the pulmonary arteries and causes pulmonary hypertension, which can progress to congestive heart failure. Cardiac troponins (cTn), which have recently been used in veterinary cardiology, are considered the gold standard because of their high sensitivity and specificity for myocardial injury. In the study, high-sensitivity cardiac troponin T (hs-cTnT) and high-sensitivity cardiac troponin I (hs-cTnI) levels in healthy …

Effects Of Replacing The Protein Content Of Azolla Pinnata With Concentrate On Physiological And Blood Profiles Changes In Sahiwal Calves, Ninad Bhatt, Ramesh Chandra, Kotresh Prasad Chikkagoudara, Diksha Kandpal, Deepesh Bharat Misra, Nitin Tyagi

Turkish Journal of Veterinary & Animal Sciences

Eighteen female Sahiwal calves of average four month of age and 54 kg body weight were selected for the study. The animals were divided into three groups (T0, T1, and T2) on body weight basis. The animals were fed as per ICAR feeding standard (2013) for calves for 90 days. The animals in T0 group T0 were fed as per feeding standard while in T1 and T2 groups, fresh Azolla pinnata was fed by replacing 15% and 30% protein content of concentrate with Azolla pinnata on DM basis. The nonsignificant results were obtained for all the physiological parameters. In addition, …

Determination Of Acrylamide Using The Immuno-Enzymatic Method In Commercial Dog And Cat Foods, Ni̇met Kiliç, Bi̇lal Cem Li̇man

Turkish Journal of Veterinary & Animal Sciences

Pet animals raised by humans do not have the chance to choose their own food. Therefore, mistakes made by humans in feeding dogs and cats will adversely affect the health of the animal. There are applications at high temperatures at various stages during the production of dog and cat foods. It is predicted that acrylamide (AA) can be formed as a result of a possible Maillard reaction since the cat and dog foods contain starch in its structure. The aim of this study is to determine the AA residue immuno-enzymatically in dry cat and dog feeds from different companies available …

Investigation Of Antimicrobial Resistance Of Esßl, Amp-C, And Carbapenemaseproducing E. Coli Strains In Retail Poultry Meats, Gülçi̇n Güven, Si̇bel Kizil

Turkish Journal of Veterinary & Animal Sciences

Antimicrobial agents are used for suppressing some bacterial infections during the rearing of poultry. In this study; the antibiotic resistance properties of Extended Spectrum ßeta-lactamase (ESßL), Amp-C, carbapenemase-producing Escherichia coli (E. coli) strains isolated from chicken breast meat were determined by disc diffusion and E-test methods. Additionally, it is aimed to determine antibiotic resistance genes by classical polymerase chain reaction (PCR). In this context, E. coli strains were isolated from 7 of 100 chicken breast meat (fillets) and identified by a rapid identification system (BBL Crystal). Disc diffusion test results of the isolates were evaluated and 100% to tetracycline; ampicillin, …

Pathological And Immunohistochemical Changes In The Liver Of Monocrotaline-Treated Rats, Şevket Soylu, Aydin Çevi̇k, Necati̇ Ti̇murkaan

Turkish Journal of Veterinary & Animal Sciences

Pathological and immunohistochemical changes in livers were investigated in monocrotaline-treated rats. Eighty adult-male Wistar rats were distributed in 5 groups, each containing 16 animals according to monocrotaline dose (Group I: 50 mg/kg, Group II: 100 mg/kg, Group III: 150 mg/kg, and Group IV: 200 mg/kg). The control group was administered with physiological saline. Half of the animals in each group were euthanized at the 18th hour while the remaining half at the 6th week postinoculation. At the end of the 18th hour, the most prominent lesion was hepatocytic apoptosis which was dose-dependent. Apoptotic cells were mostly located in periportal and …

Cryopreservation Of Nili-Ravi Buffalo Bull Semen: Yearly Postthaw Analyses To Depict Climatic Effects, Ejaz Ahmad, Muhammad Shakeel, Zahid Naseer, Adeel Ahmed, Mudussar Nawaz, Muhammad Saleem Akhtar

Turkish Journal of Veterinary & Animal Sciences

The present study was aimed to observe the postthaw quality of Nili-Ravi buffalo bull semen cryopreserved during heat stress (hot summer months) and normal climatic conditions (fall, winter, and spring months). For this purpose, four (n = 4) adult regular donor Nili-Ravi buffalo bulls were selected to collect and cryopreserve their semen throughout the period of an entire year. The cryopreservation of semen was done following standard freezing protocol. The semen doses cryopreserved during heat stress and normal climatic condition were thawed to determine the sperm motility, motion kinetics, viability, plasma membrane integrity, acrosomal integrity, and morphological abnormalities (head, mid-piece, …

Sources And Therapeutic Strategies Of Mesenchymal Stem Cells In Regenerative Medicine, Mohamed M. Kamal, Dina H. Kassem

Pharmacy

During the past decade, mesenchymal stem cells (MSCs) have made their mark as a potential weapon in regenerative medicine. Since their first isolation by Friedenstein in the late 1970s of the last century, MSCs have opened new avenues in the field of regenerative medicine. The main fascination about MSCs lies in their ease of isolation and large ex vivo expansion capacity, as well as demonstrated multipotency and immunomodulatory activities. Basically, several reports have proved that MSCs isolated from different sources possess different characteristics and potentials. In addition, the mechanisms by which these cells can help regenerate tissues and treat several …

Genome-Wide Association Study And Genomic Prediction Of White Rust Resistance In Usda Grin Spinach Germplasm, Ainong Shi, Gehendra Bhattarai, Haizheng Xiong, Carlos A. Avila, Chunda Feng, Bo Liu, Vijay Joshi, Larry Stein, Beiquan Mou, Lindsey J. Du Toit, James C. Corell

Horticulture Faculty Publications and Presentations

White rust, caused by Albugo occidentalis, is one of the major yield-limiting diseases of spinach (Spinacia oleracea) in some major commercial production areas, particularly in southern Texas in the United States. The use of host resistance is the most economical and environment-friendly approach to managing white rust in spinach production. The objectives of this study were to conduct a genome-wide associating study (GWAS), to identify single nucleotide polymorphism (SNP) markers associated with white rust resistance in spinach, and to perform genomic prediction (GP) to estimate the prediction accuracy (PA). A GWAS panel of 346 USDA (US Dept. …

Iranian Parents' Perceptions On Physical Activity For Their Children With Autism Spectrum Disorder During The Covid-19 Pandemic, Sarvin Salar, Justin A. Haegele, Hassan Daneshmandi

Human Movement Studies & Special Education Faculty Publications

Purpose: The COVID-19 pandemic is a remarkable health crisis that enforced most people to stay at home and quarantine for a period of time and seems to be having negative impacts on physical activity and mental health worldwide. Autism Spectrum Disorder (ASD), is a neurodevelopmental disorder with a deficit in social interaction characteristics, relationships, and stereotyped behaviors. This study examined Iranian parents’ perceptions of physical activity for their children with ASD during the COVID-19 pandemic.

Methods: In this study, an explanatory qualitative methodology was used and data were collected via semi-structured phone interviews. The samples included 40 Iranian parents (aged …

Meeting The 24-H Movement Guidelines And Health-Related Outcomes Among Youth With Autism Spectrum Disorder: A Seven-Country Observational Study, Chunxiao Li, Justin A. Haegele, Fenghua Sun, Maria Luiza Tanure Alves, Stefanie Hwee Chee Ang, Jihyun Lee, Kwok Ng, Isabella Dos Santos Alves, Sean Healy, Wendy Yajun Huang, Pauli Rintala, Jernice Sing Yee Tan, Yandan Wu, Hannah Yang, Eija Kärnä, Hyokju Maeng, André Lisandro Schliemann

Human Movement Studies & Special Education Faculty Publications

Background: Meeting daily guidelines for physical activity, screen time, and sleep duration is associated with a host of health indicators for youth. In this cross-sectional observational study, we investigated the associations between adherence to the movement guidelines and health-related outcomes among youth with autism spectrum disorder (ASD).

Methods: Parents of youth with ASD (10-17 years) from seven countries and regions were invited to provide online proxy-reports for child's movement behaviors (i.e., physical activity, sleep and screen time), and health-related outcomes (i.e., body mass index [BMI], general health, and quality of life). A series of multiple linear regression analyses were used …

Family Diabetes Camp Amidst Covid-19: A Community Of Practice Model, Eddie Hill, Rowan Williams, Justin Haegele, Ron Ramsing, Bethany Arrington, Laura Hill

Human Movement Studies & Special Education Faculty Publications

Studies have found that youth are experiencing higher anxiety levels than prior to COVID-19, and youth with type 1 diabetes are at higher risk. Medical specialty camps are a type of camp that provide opportunities for youth with chronic illnesses to share common goals, increase socialization, improve camper well-being, and increase knowledge of diabetes management. The program evaluation sought to determine the impact of a campers’ outcomes of independence and perceived competence and familial impact during COVID-19. Over half the participants were at their first diabetes camp and 71% of the campers felt their perceived competence “increased a little bit” …

Longitudinal Changes Of Cardiorespiratory Fitness Performance In High School: Association With Individual And School-Based Variables, Xihe Zhu, Justin A. Haegele, Jinting Shao, Summer Davis

Human Movement Studies & Special Education Faculty Publications

This study aimed to model adolescents’ cardiorespiratory fitness performance change trajectories longitudinally across high school years and its relation to school- and individual/student-level factors. We employed hierarchical linear modeling to examine longitudinal cardiorespiratory fitness performance changes, as measured by the progressive aerobic capacity endurance run (PACER), over the years, between sexes, and in association with the school-level variables. Participants were 76,227 adolescents from 80 high schools in the mid-Atlantic region of the United States. School-level academic performance (SAP), the percent of students eligible for free and reduced-price meals (FARM), and physical education student-faculty ratio were obtained with permission from the …

Environmental And Social Determinants Of Leisure-Time Physical Activity In Children With Autism Spectrum Disorder, Jihyun Lee, Sean Healy, Justin A. Haegele

Human Movement Studies & Special Education Faculty Publications

Background: It is increasingly recognized that children's physical activity behaviors are shaped by neighborhood environment factors and their parent's support. However, these factors have been scarcely studied among children with autism spectrum disorder (ASD), a population at risk of inactivity.

Objective: This cross-sectional survey study was designed to examine how neighborhood environmental factors and parental support are related to physical activity levels of children with ASD. Also, this study examined if the relationship between the environment and physical activity is modified by demographic factors and COVID-19 related concerns.

Methods: An online survey was completed by parents of children with ASD …

Consultation Summary For Proposed Declared Pest Rates 2022/2023, Department Of Primary Industries And Regional Development, Western Australia

Biosecurity published reports

In accordance with the Biosecurity and Agriculture Management (Declared Pest Account) Regulations 2014, the Minister for Agriculture and Food carries out consultation on Declared Pest Rates, to be considered prior to the rates being determined and gazetted.

This document is the Department of Primary Industries and Regional Development's response to the submissions received.

Comparative Transcriptomic Analysis Of Cancer Testis Genes In Ovarian Cancer, Zayne Knuth

Dissertations, Master's Theses and Master's Reports

Cancer testis genes are common targets for the development of immunotherapy for cancer treatment. Ovarian cancer is one of the leading causes of death in women cancer patients. Cancer testis genes play a role in tumorigenesis, but it is not clear how these genes are activated. This study utilized differential expression analysis between The Cancer Genome Atlas (TCGA) ovarian cancer data, Genotype-Tissue Expression (GTEx) non-cancerous ovary and testis data, and cell line data to identify a list of cancer testis genes that have a novel expression profile. To identify ovarian cancer testis genes, we obtained normal ovary tissue data and …

An Antimicrobial Polydopamine Surface Coating To Reduce Biofouling On Telemetry Tags Used In Marine Conservation Practices, Ariana Smies

Dissertations, Master's Theses and Master's Reports

Satellite telemetry tags are used to track the migration patterns of large cetaceans. These tags penetrate the dermis and remain embedded in the underlying blubber tissue. As the dermis of cetaceans is host to a diverse microbiome, and it is impossible to clean the skin before implanting the devices, the potential for infection is increased when the tags penetrate through the skin. H₂O₂ is a potential antimicrobial agent that, in addition to showing broad-spectrum efficacy against gram-negative and gram-positive bacteria, can promote wound healing outcomes by promoting proliferative factors and peptides that protect against oxidative stress. However, …

Spatial Heterogeneity Of Nitrogen Cycling Within And Across Freshwater Ecosystems, Erin K. Eberhard

Dissertations, Master's Theses and Master's Reports

Dinitrogen (N₂) fixation and denitrification are two nitrogen (N) cycling processes that despite differences in environmental requirements and constraints, co-occur in aquatic ecosystems. The overall goal of this dissertation was to evaluate how spatial heterogeneity of environmental variables 1) drive hot spots of N₂ fixation, denitrification rates and gene abundances in streams, 2) facilitate co-occurrence of these processes across wetland – stream – lake interfaces, and 3) affect differences in microbial community composition in streams across U.S. ecoregions. We found hot spots of both processes within 7 stream reaches in Michigan and Idaho, but rates of N …