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Individuals who identify as lesbian, gay, bisexual, transgender, queer, and otherwise nonstraight and/or non-cisgender (LGBTQ+) have often not felt welcome or represented in the biology community. Additionally, biology can present unique challenges for LGBTQ+ students because of the relationship between certain biology topics and their LGBTQ+ identities. Currently, there is no centralized set of guidelines to make biology learning environments more inclusive for LGBTQ+ individuals. Rooted in prior literature and the collective expertise of the authors who identify as members and allies of the LGBTQ+ community, we present a set of actionable recommendations to help biologists, biology educators, and biology education researchers be more inclusive of individuals with LGBTQ+ identities. These recommendations are intended to increase awareness of LGBTQ+ identities and spark conversations about transforming biology learning spaces and the broader academic biology community to become more inclusive of LGBTQ+ individuals.
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Biologia/educação , Bissexualidade , Homossexualidade Feminina , Minorias Sexuais e de Gênero , Pessoas Transgênero , Currículo , Feminino , Identidade de Gênero , Humanos , Publicações , Inquéritos e Questionários , VocabulárioRESUMO
The apical surface of mouse urothelium is covered by two-dimensional crystals (plaques) of uroplakin (UP) particles. To study uroplakin function, we ablated the mouse UPII gene. A comparison of the phenotypes of UPII- and UPIII-deficient mice yielded new insights into the mechanism of plaque formation and some fundamental features of urothelial differentiation. Although UPIII knockout yielded small plaques, UPII knockout abolished plaque formation, indicating that both uroplakin heterodimers (UPIa/II and UPIb/III or IIIb) are required for plaque assembly. Both knockouts had elevated UPIb gene expression, suggesting that this is a general response to defective plaque assembly. Both knockouts also had small superficial cells, suggesting that continued fusion of uroplakin-delivering vesicles with the apical surface may contribute to umbrella cell enlargement. Both knockouts experienced vesicoureteral reflux, hydronephrosis, renal dysfunction, and, in the offspring of some breeding pairs, renal failure and neonatal death. These results highlight the functional importance of uroplakins and establish uroplakin defects as a possible cause of major urinary tract anomalies and death.
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Proteínas de Membrana/fisiologia , Doenças Urológicas/metabolismo , Urotélio/fisiologia , Animais , Predisposição Genética para Doença , Nefropatias/genética , Nefropatias/patologia , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/fisiologia , Proteínas de Membrana/genética , Camundongos , Camundongos Knockout , Fenótipo , Doenças Urológicas/genética , Doenças Urológicas/patologia , Uroplaquina II , Uroplaquina III , Urotélio/citologia , Urotélio/patologia , Refluxo Vesicoureteral/metabolismoRESUMO
Not all instructors implement active-learning strategies in a way that maximizes student outcomes. One potential explanation for variation in active-learning effectiveness is variation in the teaching knowledge an instructor draws upon. Guided by theoretical frameworks of pedagogical content knowledge and pedagogical knowledge, this study investigated the teaching knowledge instructors used in planning, implementing, and reflecting on active-learning lessons in large courses. We used a preinstruction interview, video footage of a target class session, and a postinstruction interview with stimulated recall to elicit the teaching knowledge participants used. We then conducted qualitative content analysis to describe and contrast teaching knowledge employed by instructors implementing active learning that required students to generate their own understandings (i.e., generative instruction) and active learning largely focused on activity and recall (i.e., active instruction). Participants engaging in generative instruction exhibited teaching knowledge distinct from that of participants focused on activity. Those using generative instruction drew on pedagogical knowledge to design lessons focused on students generating reasoning; integrated pedagogical content knowledge and pedagogical knowledge to plan lessons to target student difficulties; and created opportunities to develop new pedagogical content knowledge while teaching. This work generated hypotheses about the teaching knowledge necessary for effective, generative active-learning instruction.
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Biologia/educação , Currículo , Docentes , Conhecimento , Aprendizagem Baseada em Problemas , Universidades , Humanos , Masculino , Resolução de Problemas , Estudantes , EnsinoRESUMO
BACKGROUND: Though active-learning instruction has the potential to positively impact the preparation and diversity of STEM graduates, not all instructors are able to achieve this potential. One important factor is the teacher knowledge that instructors possess, including their pedagogical knowledge. Pedagogical knowledge is the knowledge about teaching and learning that is not topic-specific, such as knowledge of learning theory, classroom management, and student motivation. We investigated the pedagogical knowledge that 77 instructors who report implementing active-learning instruction used as they analyzed video clips of lessons in large active-learning biology courses. We used qualitative content analysis, and drew on cognitive and sociocultural perspectives of learning, to identify and characterize the pedagogical knowledge instructors employed. We used the collective thinking of these instructors to generate a framework of pedagogical knowledge for active-learning instruction in large undergraduate biology courses. RESULTS: We identified seven distinct components of pedagogical knowledge, as well as connections among these components. At the core of their thinking, participants evaluated whether instruction provided opportunities for students to generate ideas beyond what was presented to them and to engage in scientific practices. They also commonly considered student motivation to engage in this work and how instruction maximized equity among students. Participants noticed whether instructors monitored and responded to student thinking in real-time, how instruction prompted metacognition, and how links were built between learning tasks. Participants also thought carefully about managing the logistics of active-learning lessons. CONCLUSIONS: Instructors who report using active-learning instruction displayed knowledge of principles of how people learn, practical knowledge of teaching strategies and behaviors, and knowledge related to classroom management. Their deep knowledge of pedagogy suggests that active-learning instruction requires much more than content knowledge built through training in the discipline, yet many college STEM instructors have little or no training in teaching. Further research should test this framework of pedagogical knowledge in different instruction contexts, including different STEM disciplines. Additional research is needed to understand what teacher knowledge is critical to effective active-learning instruction and how the development of this knowledge is best facilitated. Achieving widespread improvement in undergraduate STEM education will likely require transforming our approach to preparing and supporting undergraduate instructors.
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The Vision and Change in Undergraduate Biology Education final report challenged institutions to reform their biology courses to focus on process skills and student active learning, among other recommendations. A large southeastern university implemented curricular changes to its majors' introductory biology sequence in alignment with these recommendations. Discussion sections focused on developing student process skills were added to both lectures and a lab, and one semester of lab was removed. This curriculum was implemented using active-learning techniques paired with student collaboration. This study determined whether these changes resulted in a higher gain of student scientific literacy by conducting pre/posttesting of scientific literacy for two cohorts: students experiencing the unreformed curriculum and students experiencing the reformed curriculum. Retention of student scientific literacy for each cohort was also assessed 4 months later. At the end of the academic year, scientific literacy gains were significantly higher for students in the reformed curriculum (p = 0.005), with those students having double the scientific literacy gains of the cohort in the unreformed curriculum. Retention of scientific literacy did not differ between the cohorts.
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Biologia/educação , Currículo/normas , Competência em Informação , Estudantes , Currículo/tendências , Humanos , Alfabetização , UniversidadesRESUMO
Increasing faculty use of active-learning (AL) pedagogies in college classrooms is a persistent challenge in biology education. A large research-intensive university implemented changes to its biology majors' two-course introductory sequence as outlined by the Vision and Change in Undergraduate Biology Education final report. One goal of the curricular reform was to integrate core biological concepts and competencies into the courses using AL pedagogical approaches. The purpose of this study was to observe the instructional practices used by faculty (N = 10) throughout the 3-year process of reform to determine whether the use of AL strategies (including student collaboration) increased, given that it can maximize student learning gains. Instructors participated in yearly interviews to track any change in their perceptions of AL instruction. Instructors increased their average use of AL by 12% (group AL by 8%) of total class time throughout the 3-year study. Interviews revealed that instructors shifted their definitions of AL and talked more about how to assess student learning over the 3 years of the project. Collaboration, feedback, and time may have been important factors in the reform, suggesting that small shifts over time can accumulate into real change in the classroom.
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Biologia/educação , Docentes , Percepção , Aprendizagem Baseada em Problemas , Cultura , HumanosRESUMO
The human skin microbiome acts as an important barrier protecting our body from pathogens and other environmental influences. Recent investigations have provided evidence that Archaea are a constant but highly variable component of the human skin microbiome, yet factors that determine their abundance changes are unknown. Here, we tested the hypothesis that the abundance of archaea on human skin is influenced by human age and skin physiology by quantitative PCR of 51 different skin samples taken from human subjects of various age. Our results reveal that archaea are more abundant in human subjects either older than 60 years or younger than 12 years as compared to middle-aged human subjects. These results, together with results obtained from spectroscopy analysis, allowed us gain first insights into a potential link of lower sebum levels and lipid content and thus reduced skin moisture with an increase in archaeal signatures. Amplicon sequencing of selected samples revealed the prevalence of specific eury- and mainly thaumarchaeal taxa, represented by a core archaeome of the human skin.
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Archaea/classificação , Archaea/genética , Microbiota , Fenômenos Fisiológicos da Pele , Pele/microbiologia , Fatores Etários , Biodiversidade , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-Idade , Filogenia , RNA Ribossômico 16S , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
BACKGROUND: The ExoMars 2016 mission, consisting of the Trace Gas Orbiter and the Schiaparelli lander, was launched on March 14 2016 from Baikonur, Kazakhstan and reached its destination in October 2016. The Schiaparelli lander was subject to strict requirements for microbial cleanliness according to the obligatory planetary protection policy. To reach the required cleanliness, the ExoMars 2016 flight hardware was assembled in a newly built, biocontrolled cleanroom complex at Thales Alenia Space in Turin, Italy. In this study, we performed microbiological surveys of the cleanroom facilities and the spacecraft hardware before and during the assembly, integration and testing (AIT) activities. METHODS: Besides the European Space Agency (ESA) standard bioburden assay, that served as a proxy for the microbiological contamination in general, we performed various alternative cultivation assays and utilised molecular techniques, including quantitative PCR and next generation sequencing, to assess the absolute and relative abundance and broadest diversity of microorganisms and their signatures in the cleanroom and on the spacecraft hardware. RESULTS: Our results show that the bioburden, detected microbial contamination and microbial diversity decreased continuously after the cleanroom was decontaminated with more effective cleaning agents and during the ongoing AIT. The studied cleanrooms and change room were occupied by very distinct microbial communities: Overall, the change room harboured a higher number and diversity of microorganisms, including Propionibacterium, which was found to be significantly increased in the change room. In particular, the so called alternative cultivation assays proved important in detecting a broader cultivable diversity than covered by the standard bioburden assay and thus completed the picture on the cleanroom microbiota. CONCLUSION: During the whole project, the bioburden stayed at acceptable level and did not raise any concern for the ExoMars 2016 mission. The cleanroom complex at Thales Alenia Space in Turin is an excellent example of how efficient microbiological control is performed.
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Bactérias/isolamento & purificação , Biodiversidade , Ambiente Controlado , Microbiota , Voo Espacial , Astronave , Archaea/classificação , Archaea/genética , Archaea/isolamento & purificação , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Contaminação de Equipamentos , Europa (Continente) , Exobiologia , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Itália , RNA Ribossômico 16S , Reação em Cadeia da Polimerase em Tempo Real , TranscriptomaRESUMO
Cleanrooms have been considered microbially-reduced environments and are used to protect human health and industrial product assembly. However, recent analyses have deciphered a rather broad diversity of microbes in cleanrooms, whose origin as well as physiological status has not been fully understood. Here, we examined the input of intact microbial cells from a surrounding built environment into a spacecraft assembly cleanroom by applying a molecular viability assay based on propidium monoazide (PMA). The controlled cleanroom (CCR) was characterized by ~6.2*103 16S rRNA gene copies of intact bacterial cells per m2 floor surface, which only represented 1% of the total community that could be captured via molecular assays without viability marker. This was in contrast to the uncontrolled adjoining facility (UAF) that had 12 times more living bacteria. Regarding diversity measures retrieved from 16S rRNA Illumina-tag analyzes, we observed, however, only a minor drop in the cleanroom facility allowing the conclusion that the number but not the diversity of microbes is strongly affected by cleaning procedures. Network analyses allowed tracking a substantial input of living microbes to the cleanroom and a potential enrichment of survival specialists like bacterial spore formers and archaeal halophiles and mesophiles. Moreover, the cleanroom harbored a unique community including 11 exclusive genera, e.g., Haloferax and Sporosarcina, which are herein suggested as indicators of cleanroom environments. In sum, our findings provide evidence that archaea are alive in cleanrooms and that cleaning efforts and cleanroom maintenance substantially decrease the number but not the diversity of indoor microbiomes.
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Ambiente Controlado , Manutenção , Microbiota , Archaea/efeitos dos fármacos , Archaea/genética , Archaea/crescimento & desenvolvimento , Azidas/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Biodiversidade , Contagem de Colônia Microbiana , Variação Genética , Humanos , Viabilidade Microbiana/efeitos dos fármacos , Microbiota/efeitos dos fármacos , Microbiota/genética , Filogenia , Propídio/análogos & derivados , Propídio/farmacologia , RNA Ribossômico 16S/análise , RNA Ribossômico 16S/genéticaRESUMO
Endophytes have an intimate and often symbiotic interaction with their hosts. Less is known about the composition and function of endophytes in trees. In order to evaluate our hypothesis that plant genotype and origin have a strong impact on both, endophytes of leaves from 10 Olea europaea L. cultivars from the Mediterranean basin growing at a single agricultural site in Spain and from nine wild olive trees located in natural habitats in Greece, Cyprus, and on Madeira Island were studied. The composition of the bacterial endophytic communities as revealed by 16S rRNA gene amplicon sequencing and the subsequent PCoA analysis showed a strong correlation to the plant genotypes. The bacterial distribution patterns were congruent with the plant origins in "Eastern" and "Western" areas of the Mediterranean basin. Subsequently, the endophytic microbiome of wild olives was shown to be closely related to those of cultivated olives of the corresponding geographic origins. The olive leaf endosphere harbored mostly Proteobacteria, followed by Firmicutes, Actinobacteria, and Bacteroidetes. The detection of a high portion of archaeal taxa belonging to the phyla Thaumarchaeota, Crenarchaeota, and Euryarchaeota in the amplicon libraries was an unexpected discovery, which was confirmed by quantitative real-time PCR revealing an archaeal portion of up to 35.8%. Although the function of these Archaea for their host plant remains speculative, this finding suggests a significant relevance of archaeal endophytes for plant-microbe interactions. In addition, the antagonistic potential of culturable endophytes was determined; all isolates with antagonistic activity against the olive-pathogenic fungus Verticillium dahliae Kleb. belong to Bacillus amyloliquefaciens. In contrast to the specific global structural diversity, BOX-fingerprints of the antagonistic Bacillus isolates were highly similar and independent of the olive genotype from which they were isolated.
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Space agencies maintain highly controlled cleanrooms to ensure the demands of planetary protection. To study potential effects of microbiome control, we analyzed microbial communities in two particulate-controlled cleanrooms (ISO 5 and ISO 8) and two vicinal uncontrolled areas (office, changing room) by cultivation and 16S rRNA gene amplicon analysis (cloning, pyrotagsequencing, and PhyloChip G3 analysis). Maintenance procedures affected the microbiome on total abundance and microbial community structure concerning richness, diversity and relative abundance of certain taxa. Cleanroom areas were found to be mainly predominated by potentially human-associated bacteria; archaeal signatures were detected in every area. Results indicate that microorganisms were mainly spread from the changing room (68%) into the cleanrooms, potentially carried along with human activity. The numbers of colony forming units were reduced by up to ~400 fold from the uncontrolled areas towards the ISO 5 cleanroom, accompanied with a reduction of the living portion of microorganisms from 45% (changing area) to 1% of total 16S rRNA gene signatures as revealed via propidium monoazide treatment of the samples. Our results demonstrate the strong effects of cleanroom maintenance on microbial communities in indoor environments and can be used to improve the design and operation of biologically controlled cleanrooms.
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Microbiologia do Ar , Poluição do Ar em Ambientes Fechados , Ambiente Controlado , Archaea/classificação , Archaea/genética , Bactérias/classificação , Bactérias/genética , Biodiversidade , Análise por Conglomerados , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Metagenoma , Metagenômica/métodos , RNA Ribossômico 16S/genéticaRESUMO
The uncultivated "Candidatus Altiarchaeum hamiconexum" (formerly known as SM1 Euryarchaeon) carries highly specialized nano-grappling hooks ("hami") on its cell surface. Until now little is known about the major protein forming these structured fibrous cell surface appendages, the genes involved or membrane anchoring of these filaments. These aspects were analyzed in depth in this study using environmental transcriptomics combined with imaging methods. Since a laboratory culture of this archaeon is not yet available, natural biofilm samples with high Ca. A. hamiconexum abundance were used for the entire analyses. The filamentous surface appendages spanned both membranes of the cell, which are composed of glycosyl-archaeol. The hami consisted of multiple copies of the same protein, the corresponding gene of which was identified via metagenome-mapped transcriptome analysis. The hamus subunit proteins, which are likely to self-assemble due to their predicted beta sheet topology, revealed no similiarity to known microbial flagella-, archaella-, fimbriae- or pili-proteins, but a high similarity to known S-layer proteins of the archaeal domain at their N-terminal region (44-47% identity). Our results provide new insights into the structure of the unique hami and their major protein and indicate their divergent evolution with S-layer proteins.
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Bioburden encapsulated in spacecraft polymers (such as adhesives and coatings) poses a potential risk to jeopardize scientific exploration of other celestial bodies. This is particularly critical for spacecraft components intended for hard landing. So far, it remained unclear if polymers are indeed a source of microbial contamination. In addition, data with respect to survival of microbes during the embedding/polymerization process are sparse. In this study we developed testing strategies to quantitatively examine encapsulated bioburden in five different polymers used frequently and in large quantities on spaceflight hardware. As quantitative extraction of the bioburden from polymerized (solid) materials did not prove feasible, contaminants were extracted from uncured precursors. Cultivation-based analyses revealed <0.1-2.5 colony forming units (cfu) per cm3 polymer, whereas quantitative PCR-based detection of contaminants indicated considerably higher values, despite low DNA extraction efficiency. Results obtained from this approach reflect the most conservative proxy for encapsulated bioburden, as they give the maximum bioburden of the polymers irrespective of any additional physical and chemical stress occurring during polymerization. To address the latter issue, we deployed an embedding model to elucidate and monitor the physiological status of embedded Bacillus safensis spores in a cured polymer. Staining approaches using AlexaFluor succinimidyl ester 488 (AF488), propidium monoazide (PMA), CTC (5-cyano-2,3-diotolyl tetrazolium chloride) demonstrated that embedded spores retained integrity, germination and cultivation ability even after polymerization of the adhesive Scotch-Weld 2216 B/A. Using the methods presented here, we were able to estimate the worst case contribution of encapsulated bioburden in different polymers to the bioburden of spacecraft. We demonstrated that spores were not affected by polymerization processes. Besides Planetary Protection considerations, our results could prove useful for the manufacturing of food packaging, pharmacy industry and implant technology.
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Bacillus/isolamento & purificação , Polímeros , Astronave , Bacillus/genética , Bacillus/fisiologia , Viabilidade Microbiana , Solventes/química , Esporos Bacterianos/fisiologiaRESUMO
Similarly to Bacteria, Archaea are microorganisms that interact with their surrounding environment in a versatile manner. To date, interactions based on cellular structure and surface appendages have mainly been documented using model systems of cultivable archaea under laboratory conditions. Here, we report on the microbial interactions and ultrastructural features of the uncultivated SM1 Euryarchaeon, which is highly dominant in its biotope. Therefore, biofilm samples taken from the Sippenauer Moor, Germany, were investigated via transmission electron microscopy (TEM; negative staining, thin-sectioning) and scanning electron microscopy (SEM) in order to elucidate the fine structures of the microbial cells and the biofilm itself. The biofilm consisted of small archaeal cocci (0.6 µm diameter), arranged in a regular pattern (1.0-2.0 µm distance from cell to cell), whereas each archaeon was connected to 6 other archaea on average. Extracellular polymeric substances (EPS) were limited to the close vicinity of the archaeal cells, and specific cell surface appendages (hami, Moissl et al., 2005) protruded beyond the EPS matrix enabling microbial interaction by cell-cell contacts among the archaea and between archaea and bacteria. All analyzed hami revealed their previously described architecture of nano-grappling hooks and barb-wire basal structures. Considering the archaeal cell walls, the SM1 Euryarchaea exhibited a double-membrane, which has rarely been reported for members of this phylogenetic domain. Based on these findings, the current generalized picture on archaeal cell walls needs to be revisited, as archaeal cell structures are more complex and sophisticated than previously assumed, particularly when looking into the uncultivated majority.
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Subsurface microbial life contributes significantly to biogeochemical cycling, yet it remains largely uncharacterized, especially its archaeal members. This 'microbial dark matter' has been explored by recent studies that were, however, mostly based on DNA sequence information only. Here, we use diverse techniques including ultrastuctural analyses to link genomics to biology for the SM1 Euryarchaeon lineage, an uncultivated group of subsurface archaea. Phylogenomic analyses reveal this lineage to belong to a widespread group of archaea that we propose to classify as a new euryarchaeal order ('Candidatus Altiarchaeales'). The representative, double-membraned species 'Candidatus Altiarchaeum hamiconexum' has an autotrophic metabolism that uses a not-yet-reported Factor420-free reductive acetyl-CoA pathway, confirmed by stable carbon isotopic measurements of archaeal lipids. Our results indicate that this lineage has evolved specific metabolic and structural features like nano-grappling hooks empowering this widely distributed archaeon to predominate anaerobic groundwater, where it may represent an important carbon dioxide sink.
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Archaea/metabolismo , Carbono/metabolismo , Água Subterrânea/microbiologia , Archaea/classificação , Archaea/genética , Archaea/crescimento & desenvolvimento , Ciclo do Carbono , Água Subterrânea/análise , Dados de Sequência Molecular , FilogeniaRESUMO
The recent era of exploring the human microbiome has provided valuable information on microbial inhabitants, beneficials and pathogens. Screening efforts based on DNA sequencing identified thousands of bacterial lineages associated with human skin but provided only incomplete and crude information on Archaea. Here, we report for the first time the quantification and visualization of Archaea from human skin. Based on 16 S rRNA gene copies Archaea comprised up to 4.2% of the prokaryotic skin microbiome. Most of the gene signatures analyzed belonged to the Thaumarchaeota, a group of Archaea we also found in hospitals and clean room facilities. The metabolic potential for ammonia oxidation of the skin-associated Archaea was supported by the successful detection of thaumarchaeal amoA genes in human skin samples. However, the activity and possible interaction with human epithelial cells of these associated Archaea remains an open question. Nevertheless, in this study we provide evidence that Archaea are part of the human skin microbiome and discuss their potential for ammonia turnover on human skin.
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Archaea/genética , Microbiota/genética , Filogenia , Pele/microbiologia , Amônia/metabolismo , Archaea/metabolismo , Azidas , Sequência de Bases , Teorema de Bayes , Clonagem Molecular , Primers do DNA/genética , Alemanha , Humanos , Hibridização in Situ Fluorescente , Modelos Genéticos , Dados de Sequência Molecular , Oxirredução , Propídio/análogos & derivados , RNA Ribossômico 16S/genética , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de DNARESUMO
Successful experiments involving the production of transgenic mice by pronuclear microinjection are currently limited by low efficiency of random transgene integration into the mouse genome. Furthermore, not all transgenic mice express integrated transgenes, or in other words are effective as functional transgenic mice expressing the desired product of the transgene, thus allowing accomplishment of the ultimate experimental goal--in vivo analysis of the function of the gene or gene network. The purpose of this review is to look at the current state of transgenic technology, utilizing a pronuclear microinjection method as the most accepted way of gene transfer into the mouse genome.
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Núcleo Celular/genética , DNA/genética , Técnicas de Transferência de Genes , Camundongos Transgênicos/fisiologia , Microinjeções/métodos , Transgenes , Animais , Animais Geneticamente Modificados/genética , DNA/administração & dosagem , Modelos Animais de Doenças , Genoma , Humanos , Camundongos , Camundongos Transgênicos/genética , Plasmídeos/genéticaRESUMO
Transgenic mouse production via pronuclear microinjection is a complex process consisting of a number of sequential steps. Many different factors contribute to the effectiveness of each step and thus influence the overall efficiency of transgenic mouse production. The response of egg donor females to superovulation, the fertilization rate, egg survival after injection, ability of manipulated embryos to implant and develop to term, and concentration and purity of the injected DNA all contribute to transgenic production efficiency. We evaluated and compared the efficiency of transgenic mouse production using four different egg donor mouse strains: B6D2/F1 hybrids, Swiss Webster (SW) outbred, and inbred FVB/N and C57BL/6. The data included experiments involving approximately 350 DNA transgene constructs performed by a high capacity core transgenic mouse facility. Significant influences of particular genetic backgrounds on the efficiency of different steps of the production process were found. Except for egg production, FVB/N mice consistently produced the highest efficiency of transgenic mouse production at each step of the process. B6D2/F2 hybrid eggs are also quite efficient, but lyze more frequently than FVB/N eggs after DNA microinjection. SW eggs on the other hand block at the 1-cell stage more often than eggs from the other strains. Finally, using C57BL/6 eggs the main limiting factor is that the fetuses derived from injected eggs do not develop to term as often as the other strains. Based on our studies, the procedure for transgenic mouse production can be modified for each egg donor strain in order to overcome any deficiencies, and thus to increase the overall efficiency of transgenic mouse production.