Incubation Temperature Research Articles

Converting cellulose to biogas with anaerobic digestion at incubation temperatures of 5 °C difference in the effort for efficiency and low carbon emission

Converting cellulose to biogas with anaerobic digestion at incubation temperatures of 5 °C difference in the effort for efficiency and low carbon emission

Aptamer-Antibody Birecognized Sandwich SERRS Biosensor in Accurate and Rapid Identification of Intraoperative Parathyroid Hormone.

With the increasing incidence of thyroid cancer worldwide and the increasing demand for surgery, the risk of parathyroid injury is also increasing, which will lead to postoperative hypoparathyroidism (HP) and hypocalcemia. In order to improve the quality of life of patients after surgery, there is an urgent need to develop a novel platform that can identify the parathyroid gland immediately during surgery. The parathyroid gland promotes the increase of blood calcium concentration by secreting parathyroid hormone (PTH). Therefore, in this study, we used the sensitive surface-enhanced Raman spectroscopy (SERS) technique for rapid detection of PTH, while the near-infrared dye IR808 was used for resonance with the incident excitation wavelength of 785 nm to achieve the surface enhanced resonance Raman spectroscopy (SERRS) effect and provide a higher signal. The signal is enhanced by up to 200-fold compared to nonresonant sulfhydryl molecules. In addition, we used an aptamer-antibody mode with low Gibbs free energy (ΔG) and low dissociation constant (Kd), using the sandwich method, to achieve specific recognition of PTH. By optimizing the incubation temperature, aptamer dosage, particle concentration, and other key factors, the optimal detection conditions of the system were obtained. The sensitivity of PTH detection was as high as 9.75 pg/mL at a 5 min incubation time. In this work, we achieved an extension from standard products to rats to clinically practical samples. Finally, the eluate samples obtained from the actual clinical operations were compared with the lateral flow biosensor (LFB), chemiluminescence microparticle immunoassay (CMIA), and SERRS, respectively. Finally, using the CMIA results as the reference standard, the SERRS assay achieved a sensitivity of 94% and a specificity of 100%. This study provides new ideas and methods for the refined development of thyroid cancer surgery, improving postoperative safety and quality of life of patients, and promoting the new mode of intraoperative diagnosis and treatment.

A Study on the Preparation of Multifunctional Bacillus spp. Composite Inoculants and Their Ability to Promote Watermelon Growth

The development of plant-growth-promoting bacteria (PGPB) is one of the important research topics in agricultural microbiology. Four bacterial isolates that exhibited nitrogen fixation, phosphate and potassium solubilization, as well as indole-3-acetic acid (IAA) and siderophore production abilities, were selected from biogas residue, namely BR-1, BR-16, BR-17, and BR-44. According to morphological and molecular biological identification, BR-1, BR-16, BR-17, and BR-44 belonged to Bacillus subtilis, Bacillus cereus, Bacillus megaterium, and Bacillus subtilis, respectively. The four functional strains were combined into a composite microbial community. The optimal media were peptone (15 g/L), sucrose (10 g/L), and KCl (2 g/L); the optimal incubation conditions were an initial pH of 7.0, a volume of 47 mL/250 mL, an inoculum size of 6% v/v, an incubation temperature of 31 °C, a shaking speed of 205 r/min, and an incubation period of 20 h, as determined through a single factor test and the response surface methodology (RSM). In the optimized process, a liquid bacterial inoculant with an OD600 of 1.866 was obtained, with an effective viable count of 8.955 × 109 CFU/mL. A solid bacterial inoculant was prepared by using bran as a substrate, and its effective viable count was 1.11 × 109 CFU/g. The application of the bacterial inoculants promoted the growth of watermelon, increased the photosynthetic efficiency and yield, and improved fruit quality. This study provides a theoretical basis and technical support for the development and application of microbial inoculants.

Trichosporon asahii: A Potential Growth Promoter for C. gallinacea? Implications for Chlamydial Infections and Cell Culture

The cultivation of Chlamydia gallinacea, a recently identified species, is challenging due to the lack of an optimized protocol. In this study, several infection protocols were tested, including different cell lines, incubation temperatures, centrifugation methods and culture media. However, none were successful in field samples. The only exception was a chance co-culture with Trichosporon asahii, a microorganism commonly found in the chicken gut. This suggests that current in vitro methods may not be optimized for this species and that host-associated microorganisms may influence the in vivo growth of C. gallinacea, which is typically found in the chicken gut. These findings raise new questions and highlight the need for further investigation of microbial interactions within the host, particularly to understand their role in the proliferation of chlamydial species.

Reproductive characteristics of Japanese quail hatched from eggs incubated at different temperatures.

The objective of this study was to evaluate the influence of different incubation temperatures (ITs) on the posthatch reproductive characteristics of Japanese quails (Coturnix japonica). A total of 1332 fertile eggs were incubated at different temperatures: 36.0, 37.5 and 39.0°C. After hatching, the birds were transferred to rearing cages until 35 days of age and, later, to production cages in groups of nine females and three males. The experimental design was a randomized block with three treatments and six replications. IT did not influence (P>0.05) birth weight or hatch window; however, higher hatchability was observed (P<0.05) in eggs incubated at 37.5°C. There was no effect (P>0.05) of IT on the relative weight of organs at 35 and 60 days of age or on the male growth curve. In females, body weight at growth maturity was higher (P<0.01) when the IT was 39.0°C. The characteristics of the semen were not influenced (P>0.05) by IT, except for sperm viability, which was higher (P<0.05) when temperatures of 37.5 and 39.0°C were used. There was no effect (P<0.05) of IT on egg fertility or on the morphological characteristics of female reproductive organs. However, a lower age at first egg were observed (P<0.05) when the IT was 39.0°C. There was no effect (P>0.05) of IT on egg quality, except for yolk height, which was higher (P<0.01) at 36.0 and 39.0°C. It is concluded that a temperature of 37.5°C should be used during the incubation of Japanese quail eggs.

Optimizing proinsulin production in E. coli BL21 (DE3) using taguchi method and efficient one-step insulin purification by on-column enzymatic cleavage.

Diabetes is a critical worldwide health problem. Numerous studies have focused on producing recombinant human insulin to address this issue. In this research, the process factors of production of recombinant His-tagged proinsulin in E. coli BL21 (DE3) strain were studied. Bacterial culture factors with significant effects on the amount of produced recombinant proinsulin were screened using a Taguchi L8 orthogonal array. Proinsulin expression was conducted under predicted optimal conditions. The folded impure His-tagged proinsulin was purified using immobilized metal ion affinity chromatography (IMAC). A novel IMAC sequence order combined with the use of non-His-tagged C-peptide cleavage enzymes followed by His- tagged enterokinase enzyme enabled simultaneous protein purification and elimination of C-peptide and His-tag in just one step. Statistical analysis revealed that the amount of produced proinsulin was significantly affected by several factors including the post-induction incubation temperature, Isopropyl ß-D-1-thiogalactopyranoside (IPTG) concentration, pre-induction incubation temperature, the glucose concentration, bacterial cell population at induction step, and the time of harvesting. The optimized model resulted in an empirical maximum proinsulin concentration of 254.5 ± 11.7 µg/ml. The high purity of the purified insulin (> 96% by SDS-PAGE) indicated that applied IMAC sequence order could be considered an efficient technique for on-column cleavage and insulin purification.

The application of design of experiments and artificial neural networks in the evaluation of the impact of acidic conditions on cloud point extraction.

This study aimed to analyze the impact of acidic conditions on the recovery of ciprofloxacin and levofloxacin for cloud point extraction with the Design of Experiments and Artificial Neural Networks. The design included 27 experiments featuring three repetitions of the central point for both drugs. The tested parameters included Triton X-114 concentration, HCl concentration, NaCl concentration, and incubation temperature, which were coded at five levels. After extraction, samples were analyzed using HPLC, and statistical analysis was performed using Statistica software. Polynomial equations were developed to predict recovery values based on the experimental conditions. Results indicated that Triton X-114 concentration had the most significant impact on recovery for ciprofloxacin and levofloxacin, while HCl concentration also played an important role. The highest recovery for ciprofloxacin was observed for the following conditions: 8.5 % TX-114, 0.1 M HCl, temperature of incubation 45 °C, and no addition of NaCl. The highest recovery for levofloxacin was observed under the following conditions: 9 % TX-114, 1.5 M HCl, temperature of incubation 60 °C, and no addition of NaCl. The observed recoveries were 43 % and 53 % for levofloxacin and ciprofloxacin, respectively. They were in accordance with the predicted values calculated with DoE and with ANN approach, These findings validate the use of the Central Composite Design and Artificial Neural Networks for analyzing how acidic conditions affect the recovery of both drugs, allowing for detailed analysis and optimization of the influencing factors.

Diatom-Based Photobiological Treatment of Reverse Osmosis Concentrate: Optimization of Light and Temperature and Biomass Analysis

As global water scarcity intensifies, the desalination of brackish groundwater and surface water plays a critical role in augmenting water supplies. However, managing reverse osmosis concentrate (ROC) from brackish water desalination remains challenging due to silica and calcium accumulation and precipitation, which cause membrane scaling and reduce freshwater recovery. This study employed the brackish diatom Gedaniella flavovirens Psetr3 in a photobiological treatment to remove dissolved silica and calcium, offering a natural, sustainable solution to improve freshwater recovery. Optimal treatment conditions were identified, with a light intensity of 200 µmol m−2 s−1 and incubation temperatures between 23 °C and 30 °C maximizing silica uptake (up to 46 ± 3 mg/L/day) while minimizing diatom mortality. This study reports, for the first time, the silica, organic, and calcite content in diatom biomass and their production rates during the photobiological treatment of ROC using G. flavovirens Psetr3. The photobiological treatment of one million gallons (3785 m3) per day of ROC would produce 174 kg of silica, 163 kg of organics, and 314 kg of calcite daily. These findings provide valuable insights into the potential for utilizing these bioresources to offset the costs of photobiological treatment and subsequent desalination processes.

Ex Vivo Propagation of Pinctada Birnavirus Using Mantle Tissue Fragment Culture: Application for Measuring Replication at Different Temperatures, TCID50 Assay, and UV Sensitivity.

Pinctada birnavirus (PiBV) is the causative agent of summer atrophy in pearl oyster (Pinctada fucata (Gould)). The disease, which induces mass mortality in juveniles less than 1 year old and abnormalities in adults, was first reported in Japan in 2019. Research on the disease has been hindered by the lack of cell lines capable of propagating PiBV. We established an ex vivo method for PiBV propagation using mantle tissue, the primary infection site of the virus. The method was used to investigate the proliferation characteristics of the virus at different culture temperatures and the sensitivity of the virus to UV radiation. The marginal zone of the mantle was found to be the most suitable for PiBV replication in terms of both viral yield and reproducibility. PiBV showed optimal propagation at an incubation temperature of 25 °C, with minimal to no increase at 15 °C or 32.5 °C. Using the tissue culture infectious dose 50 (TCID50) measurement system developed in this study, we found that PiBV propagation was no longer detectable after UV irradiation at 6150 J/m2 or higher. The tissue fragment culture method developed in this study is expected to facilitate both ex vivo experiments and PiBV research.

Vechur cow milk yoghurt: response surface methodology-based process optimization and storage studies.

In this research article, response surface methodology (RSM) based optimization of three production parameters namely temperature, time and amount of starter culture of Vechur cow milk yoghurt (VCMY) on the basis of sensory evaluation responses comparing cross-bred cow milk yoghurt (CCMY) as the control is reported. The optimized values of production parameters were 2.15 per cent rate of inoculation, 42°C incubation temperature and 4 h incubation period. The optimized product exhibited significantly lower syneresis, a*, b* values and higher L* values than CCMY. Physico-chemical, microbiological, textural and sensory properties of both VCMY and CCMY during room temperature and refrigerated storage were assessed daily until the onset of spoilage (room temperature) or at five day intervals over a period of 15 d (refrigerated). Both room temperature stored products were graded undesirable by the sensory panel upon one day of storage. Significant reduction was observed in the fat, SNF, total solids, protein and pH content and all the tested colour parameters of the optimized product during refrigerated storage. Total viable counts as well as yeast and mould counts and lactic acid bacteria counts of both VCMY and CCMY progressively increased over the 15 d of storage. Significant reductions were observed in the flavour (P < 0.01), body and texture, colour and appearance and overall acceptability (P < 0.05) scores of both the samples over a period of 15 d. During storage, hardness and adhesiveness values showed an increasing trend whereas the cohesiveness showed a decreasing trend. Storage studies revealed significant differences in the acidity, pH, syneresis, tyrosine value, colour parameters and sensorial attributes of both the yoghurt samples. During the 15 d refrigerated storage period, the VCMY exhibited superior technological attributes to CCMY in terms of lower syneresis %, acidity, microbial population, firmer and less cohesive texture, better flavour, colour and appearance scores. Being the first comprehensive study on the utilization of Vechur cow milk for the preparation of yoghurt, the data generated in the current study would provide a solid base for the exploration of fermentation as a means of value addition of milk of this very rare indigenous cattle breed.

Unravelling the outcome of L-glutaminase produced by Streptomyces sp. strain 5 M as an anti-neoplasm activity

BackgroundActinomycetes are a well-known example of a microbiological origin that may generate a wide variety of chemical structures. As excellent cell factories, these sources are able to manufacture medicines, agrochemicals, and enzymes that are crucial.ResultsIn this study, about 34 randomly selected Streptomyces isolates were discovered in soil, sediment, sea water, and other environments. Using a qualitative fast plate assay, they were tested for L-glutaminase production, and nine of them produced a significant amount of pink L-glutamine. Streptomyces sp. strain 5 M was identified by examining the 16S rRNA gene in the promising strain G8. A pH of 7.5, an incubation temperature of 40 °C, and the use of glucose and peptone as the carbon and nitrogen sources, respectively, produced the highest quantities of L-glutaminase. The molecular weight of the isolated L-glutaminase was estimated to be 52 kDa using SDS-PAGE analysis. At pH 7.5 and Temp., 40 °C, the isolated enzyme exhibited its highest levels of stability and activity. The isolated enzyme’s Km and Vmax values were 2.62 mM and 10.20 U/ml, respectively. Strong toxicity against HepG-2, HeLa, and MCF-7 was observed due to the anticancer properties of the isolated L-glutaminase.ConclusionOur findings include the discovery of Streptomyces sp. strain 5 M, which yields a free L-glutaminase and maybe a possible applicant for extra pharmacological investigation as an antineoplastic drug.

Response Surface D-Optimal Design for Optimizing Fortimicins Production by Micromonospora olivasterospora and New Synergistic Fortimicin-A-Antibiotic Combinations.

Fortimicins (FTMs) are fortamine-containing aminoglycoside antibiotics (AGAs) produced by M. olivasterospora DSM 43868 with excellent bactericidal activities against a wide range of Enterobacteriaceae and synergistic activity against multidrug-resistant (MDR) pathogens. Fortimicin-A (FTM-A), the most active member of FTMs, has the lowest susceptibility to inactivation by the aminoglycoside modifying enzymes (AMEs). Therefore, this study aimed to evaluate the antibacterial activity of FTM-A alone or in combination with other antibiotics against 18 non-clonal clinically relevant MDR Gram-positive and Gram-negative pathogens. This study also aimed to statistically optimize various environmental factors affecting its production using the response surface D-optimal design. Results showed that FTM-A/meropenem combination showed the highest synergistic bactericidal activity (61.1%) followed by its combination with cefotaxime and cefepime (38.8% each). However, FTM-A/gentamicin and FTM-A/doxycycline combinations showed mostly additive effects in 66.6% and 50% of the tested isolates, respectively. For FTM-A production optimization, maximum specific activity (µg/mg) to cell growth was achieved using aminoglycoside production medium followed by yeast extract-malt extract and M65 production medium. A D-optimal quadratic model consisting of 27 different media composition variations was used to predict an optimal composition for FTM-A production and verified experimentally. Lab verification of the model was carried out using HPLC analysis, resulting in a 10.5-fold increase in their production compared to the un-optimized conditions. The model revealed that the initial pH, incubation temperature, and incubation time significantly affected FTMs production (P-value < 0.05), however, the tested range of calcium carbonate 2-7 gL-1 and agitation rate (100-300rpm) showed no significant effect (P-value > 0.05). In conclusion, the D-optimal design resulted in an effective model and optimized FTMs production on the shake flask level. FTM-A combinations with meropenem, cefotaxime, cefepime, and gentamicin showed mostly synergistic/additive effects and are advised for clinical evaluation.

Process optimization studies on xylanase production and bioethanol fermentation

Xylanase is one of the hydrolytic enzymes with a broad industrial application in several industries. Bioethanol can be synthesised from lignocellulosic biomass by using xylanase and other hydrolytic enzymes. A filamentous fungus, which is Aspergillus niger produces xylanase under submerged fermentation when oil palm empty fruit brunches were used as carbon sources. This study aimed to optimize the operating conditions (medium pH and incubation temperature) of xylanase production process using the OFAT analysis technique. From the data obtained, the highest xylanase production was 0.508 U/mL at pH 5.0 and 0.524 U/mL at an incubation temperature of 32°C, respectively. S. cerevisiae yeast was added into the fermentation supernatant for bioethanol fermentation. The concentration of bioethanol produced by xylanase enzyme from A. niger at optimum operating condition was 15.54±0.47 g/L. This study proved that A. niger is one of the filamentous fungi which show the potential of hydrolysing lignocellulosic material to carbon sources and subsequently to bioethanol production.

Effect of abiotic factors in seed germination of the medicinal aromatic plant Ziziphora hispanica L.

Summary Ziziphora hispanica L. (Lamiaceae) is a medicinal aromatic plant which is native to Algeria in semi-arid regions, Morocco and southern Spain. Despite the medicinal and economic interests as well as the uncertain future that this species may encounter in its natural habitats, various aspects of the biology of its seeds have not been recognized up to date. To fulfill these gaps, seed germination has been studied under the effect of different incubation temperatures, and under the influence of defer-ential concentrations of water stress and saline stress. The seeds were first incubated at different temperatures (15, 20 and 25°C). Then, at 20°C, germination studies were carried out at various sodium chlo-ride concentrations (0, 25, 50, 75 and 100 Mmol /l) and various solutions of polyethylene glycol (PEG6000) (0, -0.2, -0.4, and-0.6 Mpa). The results showed that Z. hispanica seeds were not dormant, and the optimal temperature of germination was 20°C, at which the maximum final germination percentage occurred (94%). A high negative correlation was obtained between the germination percentage and the various concentrations of NaCl. In comparison to other plant species that share its habitats, the results of the water stress impact tests indicate that Z. hispanica is very sensitive to water stress, indicating difficulties in germinating in semi-arid and arid regions and that climate change may restrict its natural habitats. The results of this study can serve as guidelines for propagation protocols of this species to support its conservation and cultivation.

Nucleic Acid Amplification-Lateral Flow Immunoassay (NAA-LFIA) for the Rapid Differentiation of Trypanosoma evansi and Trypanosoma equiperdum.

Trypanosoma evansi and Trypanosoma equiperdum are very difficult to distinguish morphologically. However, molecular identification algorithms sequentially using Mini and Maxi primers can distinguish the two species. Duplex polymerase chain reaction (dPCR) facilitates simultaneous amplification but is difficult to visualize with gel electrophoresis because it produces overlapping amplicons. Meanwhile, recombinase polymerase amplification (RPA) samples using two pairs of primers must be incubated separately due to differences in incubation temperature. This study aimed to evaluate the initial use of duplex lateral flow immunoassay (dLFIA) to distinguish T. evansi and T. equiperdum. The dPCR was performed by mixing two pairs of primers with the DNA template in one master mix tube, while for RPA, the Mini primer was incubated at 40 °C for 30minutes and the Maxi at 42 °C for 60minutes. The dPCR product was diluted and dropped onto the sample pad of dLFIA, while the RPA products were diluted and mixed before being dropped onto the sample pad. The results showed that dPCR had a limit of detection for nucleic acids of 102 trypanosomes/mL, while that of RPA was only 103 trypanosomes/mL. The highest agreement coefficient for trypanosome detection between dPCR-dLFIA and RPA-dLFIA was 0.875, while that for trypanosome identification and differentiation was 0.571. dLFIA revealed separate bands of the two amplicons from dPCR using Mini and Maxi primers, unlike agarose gel electrophoresis. Thus, dPCR-dLFIA successfully identified T. evansi and T. equiperdum. On the other hand, RPA-dLFIA needs further improvement to reduce species misidentification and increase its agreement with dPCR-dLFIA.

Determinants of refrigerated cow milk curd pH based on starter cultures and incubation temperatures

Determinants of refrigerated cow milk curd pH based on starter cultures and incubation temperatures

Responsiveness to cold snaps by turtle embryos depends on exposure timing and duration.

Characterizing how organisms respond to transient temperatures may further our understanding of their susceptibility to climate change. Past studies in the freshwater turtle, Trachemys scripta, have demonstrated that the timing and duration of heat waves can have major implications for the response of genes involved in gonadal development and the production of female hatchlings. Yet, no study has considered how the response of these genes to transient cold snap exposure may affect gonadal development and the production of males. We investigated how cold snap timing affects gonadal gene expression in T. scripta embryos and how the duration of an early cold snap influences the resulting hatchling sex ratios. Results show that responsiveness to cold changes rapidly across development, such that genes that responded when exposure began on incubation day 14 responded differently when exposure occurred just four or eight days later. Sex ratio data revealed that embryos experiencing an early cold snap also require a long exposure (>20 days) before most commit to testis development, suggesting that warm baseline temperatures may lower their sensitivity to later cold snap exposures. These results highlight how individual responses to incubation temperature can change rapidly across development in turtles and have important effects on sex ratios.

Embryological Incubation Temperature Modulates Behaviour and Locomotion in Larval White Sturgeon (Acispencer transmontanus)

Embryological Incubation Temperature Modulates Behaviour and Locomotion in Larval White Sturgeon (Acispencer transmontanus)

Automatic pH‐Controlled Thermal Modulation Unit for Yoghurt Production

ABSTRACTYoghurt, a widely consumed fermented dairy product, requires precise control of incubation and cooling conditions to ensure optimal fermentation and product quality. Small and medium‐scale yoghurt manufactures often face challenges in maintaining consistent temperature and pH during fermentation, leading to inconsistencies in texture, flavor, and acidity. This study addresses the problem by developing a pH‐controlled automatic thermal modulation unit. The system was designed with a goal to integrate incubation and cooling in a single system. Process simulation was used to ascertain uniform air velocity and temperature distribution. The expert pH controller monitors the fermentation conditions during yoghurt production by maintaining incubation temperatures at 40°C and once set pH is attained, the system automatically switches from incubation mode to cooling mode. The system rapidly cooled yoghurt to 4°C within 90 min halting further lactic acid production. Experimental results demonstrated uniform temperature distribution across the chamber, allowing uniform fermentation and preventing temperature‐related inconsistencies in the final product. Various textural, chemical and sensorial parameters showed significant enhancement in yoghurt produced in the automated system compared to traditionally produced yoghurt. The developed system offers several advantages by seamlessly integrating automation with both incubation and cooling processes, like reducing the overall process time, minimizing handling and operational complexities, which helps to prevent defects such as uneven texture and excessive acidity. Additionally, the system's adaptable design allows it to be customized for other fermented dairy products, providing a versatile, automated and efficient solution for small to medium‐scale dairy producers.

Assessing the Role of Incubation Temperature as a Barrier to Successful Establishment of Coho Salmon (Oncorhynchuskisutch) in a Rapidly Warming Arctic.

Warming associated with climate change is driving poleward shifts in the marine habitat of anadromous Pacific salmon (Oncorhynchus spp.). Yet the spawning locations for salmon to establish self-sustaining populations and the consequences for the ecosystem if they should do so are unclear. Here, we explore the role of temperature-dependent incubation survival and developmental phenology of coho salmon (Oncorhynchus kisutch) as a potential early life history barrier to establishment in an Arctic stream. We exposed embryos to temperatures previously recorded in the substrate of an Arctic groundwater spring-fed spawning environment. Using a common garden experimental design, coho salmon embryos were exposed to treatments that thermally mimicked four spawning dates from August 1 to October 1 (AUG1, SEPT1, SEPT15, and OCT1). Spawning temperatures were 6°C at the warmest (AUG1) and 1.25°C at the coldest (OCT1). We observed low survival rates in SEPT1 (41%) and OCT1 (34%) and near complete mortality in the other treatments. While far below what is considered normal in benign hatchery-like conditions, these rates suggest that temperatures experienced at these spawning dates are survivable. We detected differences in developmental rates across treatments; embryos developed 1.9 times faster in the warmest treatment (AUG1, 120 days) compared to the coldest (OCT1, 231 days). Differences in accumulated thermal units (ATUs) needed for hatching ranged from 392 ATUs in AUG1 to 270 ATUs in OCT1, revealing compensation in developmental requirements. Given these findings, the most thermally suitable spawning dates within our study are between September 15 and October 1, which facilitates hatching and projected nest emergence to occur in spring warming conditions (March-September). Broadly, our findings suggest that spawning sites within thermal tolerances that can support the survival and development of coho salmon exist in the North American Arctic. Whether the habitat is otherwise suitable for transitions through other life stages remains unknown.