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1.
Environ Toxicol Chem ; 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-38980316

RESUMO

The toxicity of neonicotinoids and many of their replacement insecticides to nontarget soil invertebrates such as earthworms has previously been established. However, the long-term effects of these substances on these organisms are largely unknown. In the field of soil ecotoxicology, lumbricid earthworms such as Eisenia andrei are used extensively due to the availability of standardized test methods and their adaptability to laboratory culture and testing. Multigenerational studies have gained popularity and attention in recent years, with a shift toward the use of long-term assays and lower concentrations of test chemicals. The use of exposure concentrations that include those measured in a monitoring program carried out by the Government of Ontario presents a realistic exposure scenario that may not show significant effects in contemporary, shorter term studies. We used current standardized test methods as a basis for the development of multigenerational studies on E. andrei. The effects of exposure to a single application of the insecticides thiamethoxam and cyantraniliprole on the survival and reproduction of E. andrei were observed over three (thiamethoxam) or two (cyantraniliprole) generations using consecutive reproduction tests. No significant impacts on adult survival were reported in any generation for either insecticide, whereas reproduction decreased between the first and second generations in the thiamethoxam test, with median effective concentration (EC50) values of 0.022 mg/kg dry weight reported for the first generation compared with 0.002 mg/kg dry weight in the second generation. For cyantraniliprole, an EC50 of 0.064 was determined for the first generation compared with 0.016 mg/kg dry weight in the second generation. A third generation was completed for the thiamethoxam test, and a significant decrease in reproduction was observed in all treatments and controls compared with previous generations. No significant difference between thiamethoxam treatments and the control treatment was reported for the third generation. Collectively, these data indicate that exposure of oligochaetes to these two insecticides at concentrations representative of field conditions may result in long-term stresses. Environ Toxicol Chem 2024;00:1-13. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

2.
Aesthetic Plast Surg ; 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38992248

RESUMO

The purse-string DIEPplasty technique is a method to improve aesthetic outcomes in breast reconstruction using deep inferior epigastric perforator (DIEP) free flaps. Traditionally, DIEP flaps, harvested from the lower abdomen, take on a triangular shape that can lead to sub-optimal aesthetic outcomes with occasionally poor breast projection, irregular contours, or minimal upper pole fullness. The purse-string DIEPplasty technique addresses these issues by using a 0 Polydioxanone continuous purse-string suture through the Scarpa's fascia to modify the harvested flap's shape before inset, giving it a more round base and a central dome-like projection similar to an implant. This method mimics the shape of a breast implant, enhancing the flap's projection, volumetric efficiency, and overall shape, leading to a reconstructed breast with improved aesthetic qualities. This technique represents a potential advancement in reconstructive breast surgery, aiming to reduce the extent of revision procedures and improve patient satisfaction. Further research, however, is needed to validate its effectiveness over time and assess potential complications.Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

3.
J Biol Chem ; : 107542, 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-38992436

RESUMO

Diamond Blackfan Anemia (DBA) is a rare macrocytic red blood cell aplasia that usually presents within the first year of life. The vast majority of patients carry a mutation in one of approximately 20 genes that results in ribosomal insufficiency with the most significant clinical manifestations being anemia and a predisposition to cancers. Nemo-like Kinase (NLK) is hyperactivated in the erythroid progenitors of DBA patients and inhibition of this kinase improves erythropoiesis, but how NLK contributes to the pathogenesis of the disease is unknown. Here we report that activated NLK suppresses the critical upregulation of mitochondrial biogenesis required in early erythropoiesis. During normal erythropoiesis, mTORC1 facilitates the translational upregulation of Transcription factor A, mitochondrial (TFAM) and Prohibin 2 (PHB2) to increase mitochondrial biogenesis. In our models of DBA, active NLK phosphorylates the regulatory component of mTORC1, thereby suppressing mTORC1 activity and preventing mTORC1-mediated TFAM and PHB2 upregulation and subsequent mitochondrial biogenesis. Improvement of erythropoiesis that accompanies NLK inhibition is negated when TFAM and PHB2 upregulation is prevented. These data demonstrate that a significant contribution of NLK on the pathogenesis of DBA is through loss of mitochondrial biogenesis.

4.
Langmuir ; 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38963062

RESUMO

Physical interactions between polypeptide chains and lipid membranes underlie critical cellular processes. Yet, despite fundamental importance, key mechanistic aspects of these interactions remain elusive. Bulk experiments have revealed a linear relationship between free energy and peptide chain length in a model system, but does this linearity extend to the interaction strength and to the kinetics of lipid binding? To address these questions, we utilized a combination of coarse-grained molecular dynamics (CG MD) simulations, analytical modeling, and atomic force microscopy (AFM)-based single molecule force spectroscopy. Following previous bulk experiments, we focused on interactions between short hydrophobic peptides (WLn, n = 1, ..., 5) with 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) bilayers, a simple system that probes peptide primary structure effects. Potentials of mean force extracted from CG MD recapitulated the linearity of free energy with the chain length. Simulation results were quantitatively connected to bulk biochemical experiments via a single scaling factor of order unity, corroborating the methodology. Additionally, CG MD revealed an increase in the distance to the transition state, a result that weakens the dependence of the dissociation force on the peptide chain length. AFM experiments elucidated rupture force distributions and, through modeling, intrinsic dissociation rates. Taken together, the analysis indicates a rupture force plateau in the WLn-POPC system, suggesting that the final rupture event involves the last 2 or 3 residues. In contrast, the linear dependence on chain length was preserved in the intrinsic dissociation rate. This study advances the understanding of peptide-lipid interactions and provides potentially useful insights for the design of peptides with tailored membrane-interacting properties.

6.
Sci Rep ; 14(1): 15193, 2024 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-38956145

RESUMO

Birds maintain some of the highest body temperatures among endothermic animals. Often deemed a selective advantage for heat tolerance, high body temperatures also limits birds' thermal safety margin before reaching lethal levels. Recent modelling suggests that sustained effort in Arctic birds might be restricted at mild air temperatures, which may require reductions in activity to avoid overheating, with expected negative impacts on reproductive performance. We measured within-individual changes in body temperature in calm birds and then in response to an experimental increase in activity in an outdoor captive population of Arctic, cold-specialised snow buntings (Plectrophenax nivalis), exposed to naturally varying air temperatures (- 15 to 36 °C). Calm buntings exhibited a modal body temperature range from 39.9 to 42.6 °C. However, we detected a significant increase in body temperature within minutes of shifting calm birds to active flight, with strong evidence for a positive effect of air temperature on body temperature (slope = 0.04 °C/ °C). Importantly, by an ambient temperature of 9 °C, flying buntings were already generating body temperatures ≥ 45 °C, approaching the upper thermal limits of organismal performance (45-47 °C). With known limited evaporative heat dissipation capacities in these birds, our results support the recent prediction that free-living buntings operating at maximal sustainable rates will increasingly need to rely on behavioural thermoregulatory strategies to regulate body temperature, to the detriment of nestling growth and survival.


Assuntos
Temperatura Baixa , Aves Canoras , Animais , Regiões Árticas , Aves Canoras/fisiologia , Regulação da Temperatura Corporal/fisiologia , Temperatura Corporal/fisiologia , Cruzamento , Reprodução/fisiologia , Feminino , Masculino , Temperatura
7.
Laryngoscope ; 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38984420

RESUMO

INTRODUCTION: Cervical spine defects result in spinal instability, putting the spinal cord and vertebral arteries at risk of damage and possibly devastating neurological injuries. The fibula free flap can span the spinal defects for stability. There is a paucity of literature on this technique. METHOD: Multi-institutional retrospective case series reviewing patients who underwent cervical spine reconstruction with a fibula free flap. Patient demographic information, comorbidities, characteristics of cervical spine defects, and free flap complications were collected. RESULTS: A total of 1187 fibula free flaps across 10 different institutions were reviewed. Thirteen patients (1.09%) underwent cervical spine reconstruction with a fibula free flap. Average age was 52.3 years old with an age range of 12-79 years. There were six males (46.1%) and seven females (53.8%). The most common defect etiology was infection (n = 6, 46.1%). Most commonly involved cervical spine level of the defect was C5 (n = 10) followed by C6 (n = 9) and C4 (n = 8). The majority of reconstructed defects spanned three or more cervical levels, (n = 9, 69.2%). Facial artery was the most common arterial anastomosis (n = 8). Eight patients (61.5%) required a tracheostomy during their postoperative course. None of the patients had symptomatic or radiographic nonunion. CONCLUSION: This case series demonstrates that a vascularized fibula flap is a potential reconstructive option for cervical spine defects, especially in defects greater than three cervical levels, in the setting of infection, and previously radiated patients. LEVEL OF EVIDENCE: Level 4 Laryngoscope, 2024.

8.
Artigo em Inglês | MEDLINE | ID: mdl-38953984

RESUMO

PURPOSE: In the context of ophthalmologic practice, there has been a rapid increase in the amount of data collected using electronic health records (EHR). Artificial intelligence (AI) offers a promising means of centralizing data collection and analysis, but to date, most AI algorithms have only been applied to analyzing image data in ophthalmologic practice. In this review we aimed to characterize the use of AI in the analysis of EHR, and to critically appraise the adherence of each included study to the CONSORT-AI reporting guideline. METHODS: A comprehensive search of three relevant databases (MEDLINE, EMBASE, and Cochrane Library) from January 2010 to February 2023 was conducted. The included studies were evaluated for reporting quality based on the AI-specific items from the CONSORT-AI reporting guideline. RESULTS: Of the 4,968 articles identified by our search, 89 studies met all inclusion criteria and were included in this review. Most of the studies utilized AI for ocular disease prediction (n = 41, 46.1%), and diabetic retinopathy was the most studied ocular pathology (n = 19, 21.3%). The overall mean CONSORT-AI score across the 14 measured items was 12.1 (range 8-14, median 12). Categories with the lowest adherence rates were: describing handling of poor quality data (48.3%), specifying participant inclusion and exclusion criteria (56.2%), and detailing access to the AI intervention or its code, including any restrictions (62.9%). CONCLUSIONS: In conclusion, we have identified that AI is prominently being used for disease prediction in ophthalmology clinics, however these algorithms are limited by their lack of generalizability and cross-center reproducibility. A standardized framework for AI reporting should be developed, to improve AI applications in the management of ocular disease and ophthalmology decision making.

9.
bioRxiv ; 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38979201

RESUMO

Adoptive chimeric antigen receptor T-cell (CAR-T) therapy is transformative and approved for hematologic malignancies, as well being developed for treatment of solid tumors, autoimmune disorders, heart disease and aging. Despite unprecedented clinical outcomes, CAR-T and other engineered cell therapies face a variety of manufacturing and safety challenges. Traditional methods, like lentivirus transduction and electroporation, result in random integration or cause significant cellular damage, which can limit the safety and efficacy of engineered cell therapies, such as CAR-T. We present hydroporation as a gentle and effective alternative for intracellular delivery. Hydroporation resulted in 1.7 to 2x higher CAR-T yields compared to electroporation with superior cell viability and recovery. Hydroporated cells exhibited rapid proliferation, robust target cell lysis and increased pro-inflammatory and regulatory cytokine secretion in addition to improved CAR-T yield by day 5 post-transfection. We demonstrated scaled-up hydroporation can process 5 × 10 8 cells in less than 10 s, showcasing the platform as a viable solution for high-yield CAR-T cell manufacturing with the potential for improved therapeutic outcomes.

10.
J Neural Eng ; 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38959877

RESUMO

Introduction Traditionally known for its involvement in emotional processing, the amygdala's involvement in motor control remains relatively unexplored, with sparse investigation into the neural mechanisms governing amygdaloid motor movement and inhibition. Objective This study aimed to characterize the amygdaloid beta-band (13-30 Hz) power between "Go" and "No-go" trials of an arm reaching task. Methods Ten participants with drug-resistant epilepsy implanted with stereoelectroencephalographic (SEEG) electrodes in the amygdala were enrolled in this study. SEEG data was recorded throughout discrete phases of a Direct Reach Go/No-go task, during which participants reached a touchscreen monitor or withheld movement based on a colored cue. Multitaper power analysis along with Wilcoxon signed-rank and Yates-corrected Z tests were used to assess significant modulations of beta power between the Response and Fixation (baseline) phases in the "Go" and "No-go" conditions. Results In the "Go" condition, nine out of the ten participants showed a significant decrease in relative beta-band power during the Response phase (p ≤ 0.0499). In the "No-go" condition, eight out of the ten participants presented a statistically significant increase in relative beta-band power during the Response phase (p ≤ 0.0494). Four out of the eight participants with electrodes in the contralateral hemisphere and seven out of the eight participants with electrodes in the ipsilateral hemisphere presented significant modulation in beta-band power in both the "Go" and "No-go" conditions. At the group level, no significant differences were found between the contralateral and ipsilateral sides or between genders. Conclusion This study reports beta-band power modulation in the human amygdala during voluntary movement in the setting of motor execution and inhibition. This finding supplements prior research in various brain regions associating beta-band power with motor control. The distinct beta-power modulation observed between these response conditions suggests involvement of amygdaloid oscillations in differentiating between motor inhibition and execution.

11.
Am J Audiol ; : 1-12, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38963786

RESUMO

PURPOSE: Occupational stress is known to have detrimental effects on health care professionals worldwide. This study aimed to address a research gap by investigating sources and levels of occupational stress in U.K. audiologists. METHOD: A mixed-methods cross-sectional design and convenience sampling were utilized. The study used the Audiologist Occupational Stress Questionnaire (AOSQ) and an audiological working practices questionnaire. The study included 100 registered U.K. audiologists. RESULTS: The research revealed that over a third of participants reported experiencing moderate or higher levels of occupational stress. Pediatric audiologists and those with a high daily patient load reported significantly higher stress scores than other specialties and those seeing fewer patients per day. Identified sources of stress for U.K. audiologists included clinical demands and time constraints, staffing issues, leadership in the workplace, and equipment availability. Reported impacts of stress encompassed mental health issues, fatigue, social life disruptions, and physical health concerns. CONCLUSIONS: The research validated the use of the AOSQ in a U.K. setting, and the findings provided insights into the sources and levels of occupational stress experienced by U.K. audiologists, supporting existing research on occupational stress in audiologists in other countries. The identification of consistent stress themes across the literature underscores the need for targeted support and interventions to ensure the well-being of audiologists and empower them in maintaining their pivotal role in health care.

12.
Med ; 5(7): 826-831.e3, 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-38901426

RESUMO

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) is the 6th leading cause of cancer-related mortality, with racial disparities amplifying the challenges in treatment. Although the relationship between hybrid epithelial/mesenchymal (E/M) states and tumor progression is of interest, no studies have characterized the clinical relevance of hybrid E/M states in head and neck cancer outcomes among self-reported racial cohorts. METHODS: Given the overlap in gene expression between hybrid E/M malignant cells and cancer-associated fibroblasts, we utilized deconvolution of bulk RNA sequencing data from oral cavity and laryngeal squamous cell carcinoma tumors from The Cancer Genome Atlas. We utilized our previously collected single-cell profiles to generate inferred malignant profiles and then scored these for hybrid E/M. We then conducted a survival analysis on overall and disease-free survival among self-reported Black and White Americans. FINDINGS: The hybrid E/M state was differentially associated with head and neck cancer survival by self-reported race and ethnicity, with a stronger association in non-Hispanic Black patients. Black patients with a high hybrid E/M score had a higher risk of death or recurrence (hazard ratio [HR]: 4.18 [95% confidence interval (CI): 2.06, 8.49]) than White patients with a high hybrid E/M score (HR: 1.58 [95% CI: 1.11, 2.26]). CONCLUSION: Our results suggest a complex interplay of social structure, racism, and genetic diversity. We implore researchers to consider the social and biological context contributing to disparities. FUNDING: A.L.M. received support from the National Institute of Minority Health and Health Disparities (K01MD013897 [principal investigator (PI), A.L.M.]). S.V.P. received support from the National Institute of Dental and Craniofacial Research (R01DE032865 [PI, S.V.P.] and R01DE032371 [PI, S.V.P.]).


Assuntos
Neoplasias de Cabeça e Pescoço , Autorrelato , Carcinoma de Células Escamosas de Cabeça e Pescoço , Humanos , Feminino , Masculino , Pessoa de Meia-Idade , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/etnologia , Neoplasias de Cabeça e Pescoço/patologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço/mortalidade , Carcinoma de Células Escamosas de Cabeça e Pescoço/etnologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Prognóstico , Transição Epitelial-Mesenquimal/genética , População Branca/genética , População Branca/estatística & dados numéricos , Idoso , Biomarcadores Tumorais/genética , Negro ou Afro-Americano/genética , Negro ou Afro-Americano/estatística & dados numéricos , Intervalo Livre de Doença , Análise de Sobrevida
13.
Urol Pract ; 11(4): 685-691, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38899669

RESUMO

INTRODUCTION: We sought to assess whether participant enrollment is appropriately representative of the overall urolithiasis population in published urolithiasis clinical trials. METHODS: PubMed was queried for urolithiasis US clinical trials published from 2000 to 2022. Trials were evaluated for reporting patient race/ethnicity and sex data. These were then compared to the stone prevalence reported by the National Health and Nutrition Examination Survey from 2015 to 2018. We calculated a representation quotient (RQ) to describe enrollment of patients and then stratified by geographic location, study type, and funding source. RESULTS: Of the 180 urolithiasis trials performed in the US, we identified 40 trials (22%) reporting race or ethnicity and 104 trials (58%) reporting sex. Male and female participants are well represented (RQ 0.97 and 1.02, respectively). Overall, the RQ of Black, Asian American and Pacific Islander, White, Hispanic, and mixed/other participants is 1.84, 1.06, 1.04, 0.46, and 0.34, respectively. Trials completed in the Western Section and multi-institutional trials have the most proportional enrollment, while trials in the South Central and Southeastern Sections have underrepresentation of mixed/other and Hispanic patients. Enrollment was similar among all trial subtypes. Government- and industry-funded trials had more diverse enrollment than academic-funded trials. CONCLUSIONS: Only 1 in 4 published US urolithiasis trials report race or ethnicity enrollment. Mixed race and Hispanic participants are consistently underrepresented, while Black participants are overrepresented. Government- and industry-sponsored multi-institutional trials have the most proportional representation. Investigators should prioritize inclusive recruitment and improve reporting practices to accurately reflect the diversity of the urolithiasis population.


Assuntos
Ensaios Clínicos como Assunto , Etnicidade , Seleção de Pacientes , Urolitíase , Feminino , Humanos , Masculino , Ensaios Clínicos como Assunto/estatística & dados numéricos , Etnicidade/estatística & dados numéricos , Grupos Raciais/estatística & dados numéricos , Fatores Sexuais , Estados Unidos/epidemiologia , Urolitíase/etnologia , Urolitíase/terapia , Urolitíase/epidemiologia , Diversidade, Equidade, Inclusão
14.
Reg Anesth Pain Med ; 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38901974

RESUMO

Well-established guidelines and checklists for authors, reviewers, and readers of systematic reviews and scoping reviews are readily available. However, the availability of such for narrative reviews is lacking, including, but not limited to, field-specific guidelines in the field of anesthesia and pain medicine. In this brief article, we review the differences between the major types of reviews, followed by a more detailed description of narrative reviews that clearly differentiates them from other types of reviews. We include a recommended checklist that will aid producers, editors, reviewers, and consumers of narrative reviews as well as examples specific to the field of anesthesia and pain medicine. It is the hope that the guidelines recommended here will aid producers, editors, reviewers, and consumers of narrative reviews in anesthesia and pain medicine, including Regional Anesthesia & Pain Medicine Adherence to such should help differentiate between narrative reviews and other types of reviews as well as provide consistency in what elements are necessary to include in a narrative review in the field of anesthesia and pain medicine.

15.
bioRxiv ; 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38903070

RESUMO

Broadly neutralizing antibodies targeting the V2 apex of the HIV-1 envelope trimer are among the most common specificities elicited in HIV-1-infected humans and simian-human immunodeficiency virus (SHIV)-infected macaques. To gain insight into the prevalent induction of these antibodies, we isolated and characterized 11 V2 apex-directed neutralizing antibody lineages from SHIV-infected rhesus macaques. Remarkably, all SHIV-induced V2 apex lineages were derived from reading frame two of the rhesus DH3-15*01 gene. Cryo-EM structures of envelope trimers in complex with antibodies from nine rhesus lineages revealed modes of recognition that mimicked three canonical human V2 apex-recognition modes. Notably, amino acids encoded by DH3-15*01 played divergent structural roles, inserting into a hole at the trimer apex, H-bonding to an exposed strand, or forming part of a loop scaffold. Overall, we identify a DH3-15*01-signature for rhesus V2 apex broadly neutralizing antibodies and show that highly selected genetic elements can play multiple roles in antigen recognition. Highlights: Isolated 11 V2 apex-targeted HIV-neutralizing lineages from 10 SHIV-infected Indian-origin rhesus macaquesCryo-EM structures of Fab-Env complexes for nine rhesus lineages reveal modes of recognition that mimic three modes of human V2 apex antibody recognitionAll SHIV-elicited V2 apex lineages, including two others previously published, derive from the same DH3-15*01 gene utilizing reading frame twoThe DH3-15*01 gene in reading frame two provides a necessary, but not sufficient, signature for V2 apex-directed broadly neutralizing antibodiesStructural roles played by DH3-15*01-encoded amino acids differed substantially in different lineages, even for those with the same recognition modePropose that the anionic, aromatic, and extended character of DH3-15*01 in reading frame two provides a selective advantage for V2 apex recognition compared to B cells derived from other D genes in the naïve rhesus repertoireDemonstrate that highly selected genetic elements can play multiple roles in antigen recognition, providing a structural means to enhance recognition diversity.

16.
Harmful Algae ; 136: 102656, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38876531

RESUMO

Sandusky Bay is the drowned mouth of the Sandusky River in the southwestern portion of Lake Erie. The bay is a popular recreation location and a regional source for drinking water. Like the western basin of Lake Erie, Sandusky Bay is known for being host to summer cyanobacterial harmful algal blooms (cHABs) year after year, fueled by runoff from the predominantly agricultural watershed and internal loading of legacy nutrients (primarily phosphorus). Since at least 2003, Sandusky Bay has harbored a microcystin-producing bloom of Planktothrix agardhii, a species of filamentous cyanobacteria that thrives in low light conditions. Long-term sampling (2003-2018) of Sandusky Bay revealed regular Planktothrix-dominated blooms during the summer months, but in recent years (2019-2022), 16S rRNA gene community profiling revealed that Planktothrix has largely disappeared. From 2017-2022, microcystin decreased well below the World Health Organization (WHO) guidelines. Spring TN:TP ratios increased in years following dam removal, yet there were no statistically significant shifts in other physicochemical variables, such as water temperature and water clarity. With the exception of the high bloom of Planktothrix in 2018, there was no statistical difference in chlorophyll during all other years. Concurrent with the disappearance of Planktothrix, Cyanobium spp. have become the dominant cyanobacterial group. The appearance of other potential toxigenic genera (i.e., Aphanizomenon, Dolichospermum, Cylindrospermopsis) may motivate monitoring of new toxins of concern in Sandusky Bay. Here, we document the regime shift in the cyanobacterial community and propose evidence supporting the hypothesis that the decline in the Planktothrix bloom was linked to the removal of an upstream dam on the Sandusky River.


Assuntos
Baías , Proliferação Nociva de Algas , Fitoplâncton , Planktothrix , Fitoplâncton/fisiologia , Fitoplâncton/crescimento & desenvolvimento , Baías/microbiologia , Microcistinas/metabolismo , Microcistinas/análise , Monitoramento Ambiental , Estações do Ano , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/análise , Cianobactérias/crescimento & desenvolvimento , Cianobactérias/fisiologia , Cianobactérias/genética
19.
Chaos ; 34(6)2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38865093

RESUMO

Recordings from pre-Bötzinger complex neurons responsible for the inspiratory phase of the respiratory rhythm reveal a ramping burst pattern, starting around the time that the transition from expiration to inspiration begins, in which the spike rate gradually rises until a transition into a high-frequency burst occurs. The spike rate increase along the burst is accompanied by a gradual depolarization of the plateau potential that underlies the spikes. These effects may be functionally important for inducing the onset of inspiration and hence maintaining effective respiration; however, most mathematical models for inspiratory bursting do not capture this activity pattern. Here, we study how the modulation of spike height and afterhyperpolarization via the slow inactivation of an inward current can support various activity patterns including ramping bursts. We use dynamical systems methods designed for multiple timescale systems, such as bifurcation analysis based on timescale decomposition and averaging over fast oscillations, to generate an understanding of and predictions about the specific dynamic effects that lead to ramping bursts. We also analyze how transitions between ramping and other activity patterns may occur with parameter changes, which could be associated with experimental manipulations, environmental conditions, and/or development.


Assuntos
Modelos Neurológicos , Neurônios , Neurônios/fisiologia , Animais , Potenciais de Ação/fisiologia , Retroalimentação Fisiológica/fisiologia
20.
Environ Microbiol Rep ; 16(3): e13297, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38885952

RESUMO

The Winam Gulf (Kenya) is frequently impaired by cyanobacterial harmful algal blooms (cHABs) due to inadequate wastewater treatment and excess agricultural nutrient input. While phytoplankton in Lake Victoria have been characterized using morphological criteria, our aim is to identify potential toxin-producing cyanobacteria using molecular approaches. The Gulf was sampled over two successive summer seasons, and 16S and 18S ribosomal RNA gene sequencing was performed. Additionally, key genes involved in production of cyanotoxins were examined by quantitative PCR. Bacterial communities were spatially variable, forming distinct clusters in line with regions of the Gulf. Taxa associated with diazotrophy were dominant near Homa Bay. On the eastern side, samples exhibited elevated cyrA abundances, indicating genetic capability of cylindrospermopsin synthesis. Indeed, near the Nyando River mouth in 2022, cyrA exceeded 10 million copies L-1 where there were more than 6000 Cylindrospermopsis spp. cells mL-1. In contrast, the southwestern region had elevated mcyE gene (microcystin synthesis) detections near Homa Bay where Microcystis and Dolichospermum spp. were observed. These findings show that within a relatively small embayment, composition and toxin synthesis potential of cHABs can vary dramatically. This underscores the need for multifaceted management approaches and frequent cyanotoxin monitoring to reduce human health impacts.


Assuntos
Toxinas Bacterianas , Cianobactérias , Proliferação Nociva de Algas , Lagos , Lagos/microbiologia , Lagos/química , Quênia , Cianobactérias/genética , Cianobactérias/classificação , Cianobactérias/isolamento & purificação , Cianobactérias/metabolismo , Toxinas Bacterianas/genética , Microcistinas/genética , RNA Ribossômico 16S/genética , Microbiota , Fitoplâncton/genética , Toxinas de Cianobactérias , Alcaloides/análise , Alcaloides/metabolismo , RNA Ribossômico 18S/genética , Filogenia
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