ABSTRACT
Non-invasive proxies, such as fur and feathers, are likely to be increasingly used to assess the potential exposure of chemicals, including trace metals and metalloids. However, the amount of external contamination is usually unknown, and there is no standard method for removing external contamination of trace metals in fur or feathers. To date, 40â¯% of studies published related to the measurement of trace metal levels in fur or the hair of non-human mammals and 24â¯% of studies in feathers do not state any washing methods or did not wash the samples before analysis. We assessed three washing techniques to remove external contamination of arsenic (As), lead (Pb), and zinc (Zn) from bat fur. We selected the three most frequently used fur washing methods from literature. To test these methods, fur samples from great flying foxes (Pteropus neohibernicus neohibernicus, n=15 individuals) from Papua New Guinea preserved over eight decades (AMNH, USA) were used. Percentages of trace metal removed are 87.19â¯% (SD= 12.28), 92.99â¯% (SD= 5.5) and 88.57â¯% (SD= 9.33) for As, 54.72â¯% (SD= 31.64), 55.89â¯% (SD= 37.87), and 53.93â¯% (SD= 41.28) for Pb, and 74.03â¯% (SD= 22.96), 22.93â¯% (SD= 73), and 24.95â¯% (SD= 49.5) for Zn using M2, M3, and M4, respectively. We also assessed four washing techniques to remove external contamination of arsenic (As), mercury (Hg), and zinc (Zn) from bird feathers. We identified the four most prevalent washing techniques in the literature used for feathers. We used feathers from the great horned owl (Bubo virginianus) and the great blue heron (Ardea herodias) to test these methods. Percentages of trace metal removed are 34.35â¯% (SD= 44.22), 69.22â¯% (SD= 36.5), 62.59â¯% (SD= 48.37), and 80.89â¯% (SD= 14.54) for As, 66.97â¯% (SD= 13.26), 29.4â¯% (SD= 67.06), 49.68â¯% (SD= 42.33), and 28.88â¯% (SD= 69) for Hg, and <0â¯% (SD= 80.1), 0â¯% (SD= 29.55), 11.23â¯% (SD= 47.73), and 57.09â¯% (SD= 21.2) for Zn using M2, M3, M4, and M5, respectively. This study shows the importance of washing fur and feather samples prior to trace metals analyses in ecotoxicology and biomonitoring studies.
ABSTRACT
Magnus Hirschfeld was a brilliant German doctor campaigning for the decriminalization and destigmatization of homosexuality. During the very liberal Weimar Republic (1918-1933) he published his avant-garde articles, he created his Institute of Sexual Sciences (Institut für Sexualwissenschaft), where the first published transgender surgery took place, performed on Dora Richter in 1931 (we will be interested in this first report of successful intervention) and multiplied the interventions to abolish paragraph 175, penalizing "sodomy". Ultimately the rise of Nazism forced him to flee his country and end his life in France. Hirschfeld's work remained unfinished. His political activism and his over-media coverage earned him numerous criticisms even within the gay and lesbian movement of the time. Who was this strange doctor (the Einstein of sex, as an American promoter presented him during his conferences in 1930) who combined the faults, for the time, of being at the same time Jewish, homosexual and leftist?
ABSTRACT
The study of animal movement provides insights into underlying ecological processes and informs analyses of behaviour and resource use, which have implications for species management and conservation. The tools used to study animal movement have evolved over the past decades, allowing for data collection from a variety of species, including those living in remote environments. Satellite-linked radio and GPS collars have been used to study polar bear (Ursus maritimus) ecology and movements throughout the circumpolar Arctic for over 50 years. However, due to morphology and growth constraints, only adult female polar bears can be reliably collared. Collars have proven to be safe, but there has been opposition to their use, resulting in a deficiency in data across much of the species' range. To bolster knowledge of movement characteristics and behaviours for polar bears other than adult females, while also providing an alternative to collars, we tested the use of fur- and ear-mounted telemetry tags that can be affixed to polar bears of any sex and age. We tested three fur tag designs (SeaTrkr, tribrush and pentagon tags), which we affixed to 15 adult and 1 subadult male polar bears along the coast of Hudson Bay during August-September 2021-2022. Fur tags were compared with ear tags deployed on 42 subadult and adult male polar bears captured on the coast or the sea ice between 2016 and 2022. We used data from the tags to quantify the amount of time subadult and adult males spent resting versus traveling while on land. Our results show the three fur tag designs remained functional for shorter mean durations (SeaTrkr = 58 days; tribrush = 47 days; pentagon = 22 days) than ear tags (121 days), but positional error estimates were comparable among the Argos-equipped tags. The GPS/Iridium-equipped SeaTrkr fur tags provided higher resolution and more frequent location data. Combined, the tags provided sufficient data to model different behavioural states. Furthermore, as hypothesized, subadult and adult male polar bears spent the majority of their time resting while on land, increasing time spent traveling as temperatures cooled. Fur tags show promise as a short-term means of collecting movement data from free-ranging polar bears. Supplementary Information: The online version contains supplementary material available at 10.1186/s40317-024-00373-2.
ABSTRACT
Hair cortisol concentration (HCC) and a questionnaire were used as indicators of chronic stress status and quality of life (QoL), respectively, in cats. To date, there has been limited research on the simultaneous application of both indicators in unwell cats. Our aim was to evaluate HCC and questionnaire data obtained from a healthy cat cohort (n = 61) and cat cohorts with either chronic kidney disease (CKD) (n = 78) or suspected feline infectious peritonitis (FIP) (n = 24). Furthermore, we also investigated the correlation between HCC and clinical pathological data. For this study, hair from the abdomen of cats was collected and analyzed for HCC using a commercial ELISA kit. Owners also completed a questionnaire, from which average-item-weighted-impact-scores (AWISs) were calculated. Cats with late-stage-CKD (median, HCC = 330.15 pg/mg, AWIS = -0.43) presented with a significantly higher HCC (p < 0.01) and a significantly lower AWIS (p < 0.01) than cats with early-stage-CKD (HCC = 183.56 pg/mg, AWIS = 1.08). Similarly, there were significant differences in both HCC (p < 0.001) and AWIS (p < 0.001) between cats with suspected FIP (HCC = 896.27 pg/mg, AWIS = -1.97) and healthy cats (HCC = 181.24 pg/mg, AWIS = 1.24). The degree of consistency between the HCC results and the questionnaire results reminds us that the severity of a chronic disease or the presence of a life-threatening disease can significantly increase stress and thus can affect the QoL of cats.
Subject(s)
Cat Diseases , Feline Infectious Peritonitis , Hair , Hydrocortisone , Quality of Life , Renal Insufficiency, Chronic , Animals , Cats , Surveys and Questionnaires , Renal Insufficiency, Chronic/veterinary , Renal Insufficiency, Chronic/metabolism , Hydrocortisone/analysis , Male , Hair/chemistry , Female , Stress, Physiological , Stress, PsychologicalABSTRACT
The Antarctic fur seal (Arctocephalus gazella) is an important top predator and indicator of the health of the Southern Ocean ecosystem. Although abundant, this species narrowly escaped extinction due to historical sealing and is currently declining as a consequence of climate change. Genomic tools are essential for understanding these anthropogenic impacts and for predicting long-term viability. However, the current reference genome ("arcGaz3") shows considerable room for improvement in terms of both completeness and contiguity. We therefore combined PacBio sequencing, haplotype-aware HiRise assembly and scaffolding based on Hi-C information to generate a refined assembly of the Antarctic fur seal reference genome ("arcGaz4_h1"). The new assembly is 2.53Gb long, has a scaffold N50 of 55.6Mb and includes 18 chromosome-sized scaffolds, which correspond to the 18 chromosomes expected in otariids. Genome completeness is greatly improved, with 23,408 annotated genes and a Benchmarking Universal Single-Copy Orthologs (BUSCO) score raised from 84.7% to 95.2%. We furthermore included the new genome in a reference-free alignment of the genomes of eleven pinniped species to characterize evolutionary conservation across the Pinnipedia using genome-wide Genomic Evolutionary Rate Profiling (GERP). We then implemented Gene Ontology (GO) enrichment analyses to identify biological processes associated with those genes showing the highest levels of either conservation or differentiation between the two major pinniped families, the Otariidae and Phocidae. We show that processes linked to neuronal development, the circulatory system and osmoregulation are overrepresented both in conserved as well as in differentiated regions of the genome.
ABSTRACT
Concerted conservation efforts have brought the giant panda (Ailuropoda melanoleuca) back from the brink of extinction, but pandas continue to face anthropogenic threats in the wild and breeding success in captivity remains low. Because stress can have detrimental impacts on reproduction, monitoring stress- and sex-steroid levels would help assess the effectiveness of conservation mitigation measures in panda populations as well as monitor the welfare and reproductive health of captive animals. In this proof-of-concept study, we used faecal sex steroid and cortisol concentrations (n = 867 samples collected from five males and five females at Beijing Zoo every 4 days over the course of 12 months) as a reference to investigate if testosterone, estradiol, progesterone and cortisol can be meaningfully measured in panda hair (n = 10) using radio-immuno-assays. Additionally, we calculated the ratio of testosterone to cortisol (T:C ratio) for each male, which can provide a biomarker of stress and physical performance. Our findings revealed distinct monthly variations in faecal sex-steroid and cortisol concentrations, reflecting reproductive seasonality and visitor-related stress among individual pandas. Notably, the oldest male had a significantly lower T:C ratio than other males. Our results confirm that the level of sex steroids and cortisol can be assayed by panda hair, and the hair cortisol concentrations correlate significantly with that in faeces with one month lag behind (r = 0.68, P = 0.03). However, the concentrations of hormones detected in saliva are lower than those in faeces by two orders of magnitude, making it difficult to ensure accuracy. By assessing the applicability of hair, faecal and salivary sampling, we can infer their utility in monitoring the reproductive status and acute and chronic stress levels of giant pandas, thereby providing a means to gauge the success of ongoing habitat restoration efforts and to discuss the feasibility of sample collection from wild populations.
ABSTRACT
Allergy to fur animals is becoming an increasingly common clinical problem in everyday medical practice. Depending on the route of exposure to the allergen, patients present with many, often non-specific symptoms. The most common illnesses among people with allergies to the above-mentioned allergens are as follows: allergic rhinitis, allergic conjunctivitis, atopic bronchial asthma, food allergy, allergic contact dermatitis, and sometimes anaphylactic shock. In recent years, there has been a change in the holistic approach to the treatment of allergy patients. The method of treatment should be tailored to a specific patient, taking into account his or her predispositions, economic possibilities, and therapeutic goals. The article describes the main methods of treating allergies, focusing primarily on allergies to fur animals. Allergy treatment always requires great care, and qualification for specific types of therapy should be preceded by a thorough and accurate diagnosis.
Subject(s)
Hypersensitivity , Animals , Humans , Hypersensitivity/therapy , Hypersensitivity/immunology , Allergens/immunology , Animal Fur/immunology , Food Hypersensitivity/therapy , Food Hypersensitivity/immunology , CatsABSTRACT
Exposure to mercury (Hg) may cause deleterious health effects in wildlife, including bats. Texas produces more Hg pollution than any other state in the United States, yet only one study has examined Hg accumulation in bats. This study measured the concentration of total Hg (THg) in fur (n = 411) collected from ten bat species across 32 sites in eastern and central Texas, USA. Fur THg concentrations were compared among species, and when samples sizes were large enough, between sex and life stage within a species, and the proximity to coal-fired power plants. For all sites combined and species with a sample size ≥8, mean THg concentrations (µg/g dry weight) were greatest in tri-colored bats (Perimyotis subflavus; 6.04), followed by evening bats (Nycticeius humeralis; 5.89), cave myotis (Myotis velifer; 2.11), northern yellow bats (Lasiurus intermedius; 1.85), Brazilian free-tailed bats (Tadarida brasiliensis; 1.03), and red bats (Lasiurus borealis/blossevillii; 0.974), and lowest in hoary bats (Lasiurus cinereus; 0.809). Within a species, fur THg concentrations did not significantly vary between sex for the five examined species (red bat, northern yellow bat, cave myotis, evening bat, Brazilian free-tailed bat) and only between life stage in evening bats. Site variations in fur THg concentrations were observed for evening bats, tri-colored bats, and Brazilian free-tailed bats. Evening bats sampled closer to point sources of Hg pollution had greater fur THg concentrations than individuals sampled further away. Sixteen percent of evening bats and 8.7% of tri-colored bats had a fur THg concentration exceeding the 10 µg/g toxicity threshold level, suggesting that THg exposure may pose a risk to the health of bats in Texas, particularly those residing in east Texas and on the upper Gulf coast. The results of this study can be incorporated into future management and recovery plans for bats in Texas.
ABSTRACT
Staphylococcus aureus has evolved mechanisms to cope with low iron (Fe) availability in host tissues. S. aureus uses the ferric uptake transcriptional regulator (Fur) to sense titers of cytosolic Fe. Upon Fe depletion, apo-Fur relieves transcriptional repression of genes utilized for Fe uptake. We demonstrate that an S. aureus Δfur mutant has decreased expression of acnA, which codes for the Fe-dependent enzyme aconitase. Decreased acnA expression prevented the Δfur mutant from growing with amino acids as sole carbon and energy sources. Suppressor analysis determined that a mutation in isrR, which produces a regulatory RNA, permitted growth by decreasing isrR transcription. The decreased AcnA activity of the Δfur mutant was partially relieved by an ΔisrR mutation. Directed mutation of bases predicted to facilitate the interaction between the acnA transcript and IsrR, decreased the ability of IsrR to control acnA expression in vivo and IsrR bound to the acnA transcript in vitro. IsrR also bound to the transcripts coding the alternate TCA cycle proteins sdhC, mqo, citZ, and citM. Whole cell metal analyses suggest that IsrR promotes Fe uptake and increases intracellular Fe not ligated by macromolecules. Lastly, we determined that Fur and IsrR promote infection using murine skin and acute pneumonia models.
ABSTRACT
Forest fragmentation and edge effects are two major threats to primate populations. Primates inhabiting fragmented landscapes must survive in a more degraded environment, often with lower food availability compared to continuous forests. Such conditions can have deleterious effects on animal physiological health, yet some primates thrive in these habitats. Here, we assessed how forest fragmentation and associated edge effects impact three different components of physiological health in a nocturnal primate community in the Sahamalaza-Iles Radama National Park, northwest Madagascar. Over two periods, 6 March 2019-30 October 2019 and 10 January 2022-17 May 2022, we collected data on body condition, fur condition scores and ectoparasite prevalence for 125 Mirza zaza, 51 Lepilemur sahamalaza, 27 Cheirogaleus medius and 22 Microcebus sambiranensis individuals, and we compared these metrics between core and edge areas of continuous forest and fragmented forest. Body condition scores for all species varied between areas, with a positive response to fragmentation and edge effects observed for M. zaza and L. sahamalaza and a negative response for C. medius and M. sambiranensis. Fur condition scores and ectoparasite prevalence were less variable, although M. zaza and L. sahamalaza had a significantly negative response to fragmentation and edge effects for these two variables. Interestingly, the impacts of fragmentation and edge effects on physiological health were variable-specific. Our results suggest that lemur physiological responses to fragmentation and edge effects are species-specific, and body condition, fur condition and ectoparasite prevalence are impacted in different ways between species. As other ecological factors, including food availability and inter/intraspecific competition, likely also influence physiological health, additional work is required to determine why certain aspects of lemur physiology are affected by environmental stressors while others remain unaffected. Although many nocturnal lemurs demonstrate resilience to fragmented and degraded habitats, urgent conservation action is needed to safeguard the survival of their forest habitats.
ABSTRACT
Charcot arthropathy is a rare disease in clinic, which is easy to be misdiagnosed and delayed diagnosis. Imaging examination plays a key role in the diagnosis of Charcot arthropathy. It is important to improve the early diagnosis rate and strive for early treatment to improve the quality of life of these patients. Here we reported a rare case of charcot knee (CK) accompanied by tethered cord syndrome and lumbosacral fur sinus, who presented with joint destruction, joint deformity and multiple free bodies and received joint free bodies removal and joint replacement surgery with acceptable short and midterm follow-up results.
ABSTRACT
The origins and extreme morphological evolution of the modern dog breeds are poorly studied because the founder populations are extinct. Here, we analyse eight 100 to 200 years old dog fur samples obtained from traditional North Swedish clothing, to explore the origin and artificial selection of the modern Nordic Lapphund and Elkhound dog breeds. Population genomic analysis confirmed the Lapphund and Elkhound breeds to originate from the local dog population, and showed a distinct decrease in genetic diversity in agreement with intense breeding. We identified eleven genes under positive selection during the breed development. In particular, the MSRB3 gene, associated with breed-related ear morphology, was selected in all Lapphund and Elkhound breeds, and functional assays showed that a SNP mutation in the 3'UTR region suppresses its expression through miRNA regulation. Our findings demonstrate analysis of near-modern dog artifacts as an effective tool for interpreting the origin and artificial selection of the modern dog breeds.
Subject(s)
Animal Fur , Selection, Genetic , Animals , Dogs/genetics , Polymorphism, Single Nucleotide , Breeding , Sweden , Genetic Variation , MicroRNAs/geneticsABSTRACT
Highly pathogenic avian influenza (HPAI) has caused widespread mortality in both wild and domestic birds in Europe 2020-2023. In July 2023, HPAI A(H5N1) was detected on 27 fur farms in Finland. In total, infections in silver and blue foxes, American minks and raccoon dogs were confirmed by RT-PCR. The pathological findings in the animals include widespread inflammatory lesions in the lungs, brain and liver, indicating efficient systemic dissemination of the virus. Phylogenetic analysis of Finnish A(H5N1) strains from fur animals and wild birds has identified three clusters (Finland I-III), and molecular analyses revealed emergence of mutations known to facilitate viral adaptation to mammals in the PB2 and NA proteins. Findings of avian influenza in fur animals were spatially and temporally connected with mass mortalities in wild birds. The mechanisms of virus transmission within and between farms have not been conclusively identified, but several different routes relating to limited biosecurity on the farms are implicated. The outbreak was managed in close collaboration between animal and human health authorities to mitigate and monitor the impact for both animal and human health.
Subject(s)
Animals, Wild , Charadriiformes , Disease Outbreaks , Influenza A Virus, H5N1 Subtype , Influenza in Birds , Phylogeny , Animals , Influenza in Birds/virology , Influenza in Birds/epidemiology , Finland/epidemiology , Influenza A Virus, H5N1 Subtype/genetics , Influenza A Virus, H5N1 Subtype/pathogenicity , Influenza A Virus, H5N1 Subtype/isolation & purification , Animals, Wild/virology , Charadriiformes/virology , Disease Outbreaks/veterinary , Farms , Orthomyxoviridae Infections/veterinary , Orthomyxoviridae Infections/virology , Orthomyxoviridae Infections/mortality , Orthomyxoviridae Infections/epidemiology , Foxes/virology , Birds/virology , Mink/virologyABSTRACT
Traffic lights play vital roles in urban traffic management systems, providing clear directional guidance for vehicles and pedestrians while ensuring traffic safety. However, the vast quantity of traffic lights widely distributed in the transportation system aggravates energy consumption. Here, a self-powered traffic light system is proposed through wind energy harvesting based on a high-performance fur-brush dish triboelectric nanogenerator (FD-TENG). The FD-TENG harvests wind energy to power the traffic light system continuously without needing an external power supply. Natural rabbit furs are applied to dish structures, due to their outstanding characteristics of shallow wear, high performance, and resistance to humidity. Also, the grid pattern of the dish structure significantly impacts the TENG outputs. Additionally, the internal electric field and the influences of mechanical and structural parameters on the outputs are analyzed by finite element simulations. After optimization, the FD-TENG can achieve a peak power density of 3.275 W m-3. The portable and miniature features of FD-TENG make it suitable for other natural environment systems such as forests, oceans, and mountains, besides the traffic light systems. This study presents a viable strategy for self-powered traffic lights, establishing a basis for efficient environmental energy harvesting toward big data and Internet of Things applications.
ABSTRACT
BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease. SFTS virus (SFTSV) is transmitted by tick bites and contact with the blood or body fluids of SFTS patients. Animal-to-human transmission of SFTS has been reported in Japan, but not in China. In this study, the possible transmission route of two patients who fed and cared for farm-raised fur animals in a mink farm was explored. METHOD: An epidemiological investigation and a genetic analysis of patients, animals and working environment were carried out. RESULTS: It was found that two patients had not been bitten by ticks and had no contact with patients infected with SFTS virus, but both of them had skinned the dying animals. 54.55% (12/22) of the farm workers were positive for SFTS virus antibody. By analyzing the large, medium and small segments sequences, the viral sequences from the two patients, animals and environments showed 99.9% homology. CONCLUSION: It is suspected that the two patients may be directly infected by farm-raised animals, and that the virus may have been transmitted by aerosols when skinning dying animals. Transmission by direct blood contacts or animal bites cannot be ignored.
Subject(s)
Phlebovirus , Severe Fever with Thrombocytopenia Syndrome , Animals , Humans , Antibodies, Viral/blood , China/epidemiology , Farmers , Farms , Mink/virology , Phlebovirus/genetics , Phlebovirus/isolation & purification , Phlebovirus/classification , Phylogeny , RNA, Viral/genetics , Severe Fever with Thrombocytopenia Syndrome/transmission , Severe Fever with Thrombocytopenia Syndrome/virology , Severe Fever with Thrombocytopenia Syndrome/epidemiologyABSTRACT
Bacteria contain conserved mechanisms to control the intracellular levels of metal ions. Metalloregulatory transcription factors bind metal cations and play a central role in regulating gene expression of metal transporters. Often, these transcription factors regulate transcription by binding to a specific DNA sequence in the promoter region of target genes. Understanding the preferred DNA-binding sequence for transcriptional regulators can help uncover novel gene targets and provide insight into the biological role of the transcription factor in the host organism. Here, we identify consensus DNA-binding sequences and subsequent transcription regulatory networks for two metalloregulators from the ferric uptake regulator (FUR) and diphtheria toxin repressor (DtxR) superfamilies in Thermus thermophilus HB8. By homology search, we classify the DtxR homolog as a manganese-specific, MntR (TtMntR), and the FUR homolog as a peroxide-sensing, PerR (TtPerR). Both transcription factors repress separate ZIP transporter genes in vivo, and TtPerR acts as a bifunctional transcription regulator by activating the expression of ferric and hemin transport systems. We show TtPerR and TtMntR bind DNA in the presence of manganese in vitro and in vivo; however, TtPerR is unable to bind DNA in the presence of iron, likely due to iron-mediated histidine oxidation. Unlike canonical PerR homologs, TtPerR does not appear to contribute to peroxide detoxification. Instead, the TtPerR regulon and DNA binding sequence are more reminiscent of Fur or Mur homologs. Collectively, these results highlight the similarities and differences between two metalloregulatory superfamilies and underscore the interplay of manganese and iron in transcription factor regulation.
Subject(s)
Bacterial Proteins , Gene Expression Regulation, Bacterial , Manganese , Promoter Regions, Genetic , Repressor Proteins , Thermus thermophilus , Transcription Factors , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Thermus thermophilus/genetics , Thermus thermophilus/metabolism , Repressor Proteins/metabolism , Repressor Proteins/genetics , Manganese/metabolism , Promoter Regions, Genetic/genetics , Transcription Factors/metabolism , Transcription Factors/genetics , Iron/metabolism , Transcription, Genetic , DNA-Binding Proteins/metabolism , DNA-Binding Proteins/genetics , Binding SitesABSTRACT
Patella fractures usually occur as a result of direct trauma to the anterior knee joint, indirect injury as a result of eccentric muscle contraction, or rapid knee flexion against a contracted quadriceps muscle. The patella functions as part of the extensor mechanism of the knee, where large forces are transmitted, and its subcutaneous nature has made treatment of patella fractures a challenge. In this review article, we evaluate how the management of these fractures has evolved over time and the advantages associated with the various treatment techniques. There are few comparative studies looking at the different treatment types for fractures of the patella, with the goal of achieving a functional extensor mechanism with low rates of post-traumatic arthritis and metal-work irritation.
ABSTRACT
Introduction: The hemin acquisition system is composed of an outer membrane TonB-dependent transporter that internalizes hemin into the periplasm, periplasmic hemin-binding proteins to shuttle hemin, an inner membrane transporter that transports hemin into the cytoplasm, and cytoplasmic heme oxygenase to release iron. Fur and HemP are two known regulators involved in the regulation of hemin acquisition. The hemin acquisition system of Stenotrophomonas maltophilia is poorly understood, with the exception of HemA as a TonB-dependent transporter for hemin uptake. Methods: Putative candidates responsible for hemin acquisition were selected via a homolog search and a whole-genome survey of S. maltophilia. Operon verification was performed by reverse transcription-polymerase chain reaction. The involvement of candidate genes in hemin acquisition was assessed using an in-frame deletion mutant construct and iron utilization assays. The transcript levels of candidate genes were determined using quantitative polymerase chain reaction. Results: Smlt3896-hemU-exbB2-exbD2-tonB2 and tonB1-exbB1-exbD1a-exbD1b operons were selected as candidates for hemin acquisition. Compared with the parental strain, hemU and tonB1 mutants displayed a defect in their ability to use hemin as the sole iron source for growth. However, hemin utilization by the Smlt3896 and tonB2 mutants was comparable to that of the parental strain. HemA expression was repressed by Fur in iron-replete conditions and derepressed in iron-depleted conditions. HemP negatively regulated hemA expression. Like hemA, hemU was repressed by Fur in iron-replete conditions; however, hemU was moderately derepressed in response to iron-depleted stress and fully derepressed when hemin was present. Unlike hemA and hemU, the TonB1-exbB1-exbD1a-exbD1b operon was constitutively expressed, regardless of the iron level or the presence of hemin, and Fur and HemP had no influence on its expression. Conclusion: HemA, HemU, and TonB1 contribute to hemin acquisition in S. maltophilia. Fur represses the expression of hemA and hemU in iron-replete conditions. HemA expression is regulated by low iron levels, and HemP acts as a negative regulator of this regulatory circuit. HemU expression is regulated by low iron and hemin levels in a hemP-dependent manner.
Subject(s)
Hemin , Stenotrophomonas maltophilia , Stenotrophomonas maltophilia/genetics , Stenotrophomonas maltophilia/metabolism , Bacterial Proteins/metabolism , Membrane Proteins/genetics , Membrane Proteins/metabolism , Iron/metabolismABSTRACT
Environmental enrichment may reduce stereotypies in fur-farmed mink. North American mink standards require manipulable enrichment objects within cages. However, mink can rapidly destroy objects inhibiting continuous enrichment presence, which may have negative welfare impacts. This experimental study determined the effects of removing simple cage manipulable enrichments (plastic chains and dumbbells), either short-term or longer-term, on the behavioral expression of welfare in fur-farmed mink. Locomotor stereotypies, normal activity, sub-types of inactivity related to boredom, and tail fur-chewing were recorded across four treatment groups with either (1) no enrichment, (2) continuous enrichment, (3) short (temporary), or (4) long-term enrichment removal. Contrary to predictions, locomotor stereotypies, and scrabbling were not reduced by the enrichments, nor affected by the enrichment removal. Observations at the beginning of the trial showed the non-enriched mink spent the least amount of time lying with their eyes open (i.e., the least bored). The lack of enrichment may have increased fur-chewing on the tail, but larger sample sizes would be needed for statistical confirmation. This research contributes to the literature on evaluating simple, practical enrichments for improving fur-farmed mink welfare.