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Fleeman RM, Mikesh M, Davies BW. Investigating Klebsiella pneumoniae biofilm preservation for scanning electron microscopy. Access Microbiol 2023; 5:000470.v3. [PMID: 36910511 PMCID: PMC9996182 DOI: 10.1099/acmi.0.000470.v3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 01/02/2023] [Indexed: 02/05/2023] Open
Abstract
Klebsiella pneumoniae biofilm formation is associated with chronic and relapsing infections. Scanning electron microscopy (SEM) is a powerful tool for characterizing biofilm structure and studying their formation. Reliable visualization of biofilm structure requires careful sample preservation, otherwise there may be loss of non-covalent interactions that are susceptible to damage during the dehydration and washing preparation steps. However, no standard procedure has been adopted in the literature to fix K. pneumoniae biofilm for scanning electron microscopy studies. This lack of standardization makes it challenging to compare results between studies and determine the degree to which native structures have been preserved. To advance this critical area of study, we investigated different scanning electron microscopy fixation methods for K. pneumoniae biofilm preservation. Our study reveals the impact preparation steps can have on retaining in biofilm architecture observed using scanning electron microscopy. Using fixation methods developed through our studies, we show that although species that overproduce capsular extracellular polysaccharides produced more robust biofilms, K. pneumoniae can form a developed biofilm in the absence of capsular polysaccharides.
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Affiliation(s)
- Renee M. Fleeman
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
- Present address: Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32837, USA
| | - Michelle Mikesh
- Center for Biomedical Research Support, The University of Texas at Austin, Austin, TX 78712, USA
| | - Bryan W. Davies
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
- Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
- John Ring LaMontagne Center for Infectious Diseases, The University of Texas at Austin, Austin, TX 78712, USA
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Trainin T, Brukental H, Shapira O, Attia Z, Tiwari V, Hatib K, Gal S, Zemach H, Belausov E, Charuvi D, Holland D, Azoulay-Shemer T. Physiological characterization of the wild almond Prunus arabica stem photosynthetic capability. FRONTIERS IN PLANT SCIENCE 2022; 13:941504. [PMID: 35968090 PMCID: PMC9372545 DOI: 10.3389/fpls.2022.941504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 07/08/2022] [Indexed: 06/15/2023]
Abstract
Leaves are the major plant tissue for transpiration and carbon fixation in deciduous trees. In harsh habitats, atmospheric CO2 assimilation via stem photosynthesis is common, providing extra carbon gain to cope with the detrimental conditions. We studied two almond species, the commercial Prunus dulcis cultivar "Um-el-Fahem" and the rare wild Prunus arabica. Our study revealed two distinctive strategies for carbon gain in these almond species. While, in P. dulcis, leaves possess the major photosynthetic surface area, in P. arabica, green stems perform this function, in particular during the winter after leaf drop. These two species' anatomical and physiological comparisons show that P. arabica carries unique features that support stem gas exchange and high-gross photosynthetic rates via stem photosynthetic capabilities (SPC). On the other hand, P. dulcis stems contribute low gross photosynthesis levels, as they are designed solely for reassimilation of CO2 from respiration, which is termed stem recycling photosynthesis (SRP). Results show that (a) P. arabica stems are covered with a high density of sunken stomata, in contrast to the stomata on P. dulcis stems, which disappear under a thick peridermal (bark) layer by their second year of development. (b) P. arabica stems contain significantly higher levels of chlorophyll compartmentalized to a mesophyll-like, chloroplast-rich, parenchyma layer, in contrast to rounded-shape cells of P. dulcis's stem parenchyma. (c) Pulse amplitude-modulated (PAM) fluorometry of P. arabica and P. dulcis stems revealed differences in the chlorophyll fluorescence and quenching parameters between the two species. (d) Gas exchange analysis showed that guard cells of P. arabica stems tightly regulate water loss under elevated temperatures while maintaining constant and high assimilation rates throughout the stem. Our data show that P. arabica uses a distinctive strategy for tree carbon gain via stem photosynthetic capability, which is regulated efficiently under harsh environmental conditions, such as elevated temperatures. These findings are highly important and can be used to develop new almond cultivars with agriculturally essential traits.
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Affiliation(s)
- Taly Trainin
- Department of Fruit Tree Sciences, Volcani Center, Newe Ya'ar Research Center, Agricultural Research Organization, Ramat Yishay, Israel
| | - Hillel Brukental
- Department of Fruit Tree Sciences, Volcani Center, Newe Ya'ar Research Center, Agricultural Research Organization, Ramat Yishay, Israel
- Faculty of Agriculture, The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot, Israel
| | - Or Shapira
- Department of Fruit Tree Sciences, Volcani Center, Newe Ya'ar Research Center, Agricultural Research Organization, Ramat Yishay, Israel
| | - Ziv Attia
- Department of Fruit Tree Sciences, Volcani Center, Newe Ya'ar Research Center, Agricultural Research Organization, Ramat Yishay, Israel
| | - Vivekanand Tiwari
- Volcani Center, Institute of Plant Sciences, Agricultural Research Organization, Rishon LeZion, Israel
| | - Kamel Hatib
- Department of Fruit Tree Sciences, Volcani Center, Newe Ya'ar Research Center, Agricultural Research Organization, Ramat Yishay, Israel
| | - Shira Gal
- Department of Fruit Tree Sciences, Volcani Center, Newe Ya'ar Research Center, Agricultural Research Organization, Ramat Yishay, Israel
| | - Hanita Zemach
- Volcani Center, Institute of Plant Sciences, Agricultural Research Organization, Rishon LeZion, Israel
| | - Eduard Belausov
- Volcani Center, Institute of Plant Sciences, Agricultural Research Organization, Rishon LeZion, Israel
| | - Dana Charuvi
- Volcani Center, Institute of Plant Sciences, Agricultural Research Organization, Rishon LeZion, Israel
| | - Doron Holland
- Department of Fruit Tree Sciences, Volcani Center, Newe Ya'ar Research Center, Agricultural Research Organization, Ramat Yishay, Israel
| | - Tamar Azoulay-Shemer
- Department of Fruit Tree Sciences, Volcani Center, Newe Ya'ar Research Center, Agricultural Research Organization, Ramat Yishay, Israel
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Naseer M, Zhu Y, Li FM, Yang YM, Wang S, Xiong YC. Nano-enabled improvements of growth and colonization rate in wheat inoculated with arbuscular mycorrhizal fungi. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 295:118724. [PMID: 34942289 DOI: 10.1016/j.envpol.2021.118724] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/19/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
Arbuscular mycorrhizal fungi display desired potential to boost crop productivity and drought acclimation. Yet, whether nanoparticles can be incorporated into arbuscular mycorrhizal fungi for better improvement and its relevant morphologic and anatomical evidences are little documented. Pot culture experiment on wheat (Triticum aestivum L.) was conducted under drought stress (30% FWC) as well as well watered conditions (80% FWC) that involved priming of wheat seeds with iron nanoparticles at different concentrations (5mg L-1, 10 mg L-1 and 15 mg L-1) with and without the inoculation of Glomus intraradices. The effects of treatments were observed on morphological and physiological parameters across jointing, anthesis and maturity stage. Root colonization and nanoparticle uptake trend by seeds and roots was also recorded. We observed strikingly high enhancement in biomass up to 109% under drought and 71% under well-watered conditions, and grain yield increased to 163% under drought and 60% under well-watered conditions. Iron nanoparticles at 10 mg L-1 when combined with Glomus intraradices resulted in maximum wheat growth and yield, which mechanically resulted from higher rhizosphere colonization level, water use efficiency and photosynthetic rate under drought stress (P < 0.01). Across growth stages, optical micrograph observations affirmed higher root infection rate when combined with nanoparticles. Transmission electron microscopy indicated the penetration of nanoparticles into the seeds and translocation across roots whereas energy dispersive X-ray analyses further confirmed the presence of Fe in these organs. Iron nanoparticles significantly enhanced the growth-promoting and drought-tolerant effects of Glomus intraradices on wheat.
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Affiliation(s)
- Minha Naseer
- State Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Ying Zhu
- State Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China; Key Laboratory of Microbial Resources Exploitation and Application of Gansu Province, Institute of Biology, Gansu Academy of Sciences, Lanzhou, 730000, China
| | - Feng-Min Li
- State Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Yu-Miao Yang
- State Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Song Wang
- State Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - You-Cai Xiong
- State Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
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Jinqiu Y, Bing L, Tingting S, Jinglei H, Zelai K, Lu L, Wenhua H, Tao H, Xinyu H, Zengqing L, Guowen C, Yajun C. Integrated Physiological and Transcriptomic Analyses Responses to Altitude Stress in Oat ( Avena sativa L.). Front Genet 2021; 12:638683. [PMID: 34220929 PMCID: PMC8248544 DOI: 10.3389/fgene.2021.638683] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 02/23/2021] [Indexed: 12/17/2022] Open
Abstract
Oat is an annual gramineous forage grass with the remarkable ability to survive under various stressful environments. However, understanding the effects of high altitude stresses on oats is poor. Therefore, the physiological and the transcriptomic changes were analyzed at two sites with different altitudes, low (ca. 2,080 m) or high (ca. 2,918 m), respectively. Higher levels of antioxidant enzyme activity, reactive oxygen and major reductions in photosynthesis-related markers were suggested for oats at high altitudes. Furthermore, oat yields were severely suppressed at the high altitude. RNA-seq results showed that 11,639 differentially expressed genes were detected at both the low and the high altitudes in which 5,203 up-regulated and 6,436 down-regulated. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment tests were conducted and a group of major high altitude-responsive pigment metabolism genes, photosynthesis, hormone signaling, and cutin, suberine and wax biosynthesis were excavated. Using quantitative real-time polymerase chain response, we also confirmed expression levels of 20 DEGs (qRT-PCR). In summary, our study generated genome-wide transcript profile and may be useful for understanding the molecular mechanisms of Avena sativa L. in response to high altitude stress. These new findings contribute to our deeper relevant researches on high altitude stresses and further exploring new candidategenes for adapting plateau environment oat molecular breeding.
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Affiliation(s)
- Yu Jinqiu
- Department of Grassland Science, College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Li Bing
- Department of Grassland Science, College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Song Tingting
- Department of Grassland Science, College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - He Jinglei
- Department of Grassland Science, College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - KongLing Zelai
- Department of Grassland Science, College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Lian Lu
- College of Grassland Science and Technology, China Agricultural University, Beijing, China
| | - He Wenhua
- Department of Grassland Science, College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Hai Tao
- Department of Grassland Science, College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Huang Xinyu
- Heilongjiang Academy of Agricultural Sciences, Qiqihar, China
| | - Liu Zengqing
- Department of Grassland Science, College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Cui Guowen
- Department of Grassland Science, College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Chen Yajun
- Department of Grassland Science, College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
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Matthaeus WJ, Schmidt J, White JD, Zechmann B. Novel perspectives on stomatal impressions: Rapid and non-invasive surface characterization of plant leaves by scanning electron microscopy. PLoS One 2020; 15:e0238589. [PMID: 32881951 PMCID: PMC7470294 DOI: 10.1371/journal.pone.0238589] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 08/19/2020] [Indexed: 11/18/2022] Open
Abstract
Scanning electron microscopy (SEM) is widely used to investigate the surface morphology, and physiological state of plant leaves. Conventionally used methods for sample preparation are invasive, irreversible, require skill and expensive equipment, and are time and labor consuming. This study demonstrates a method to obtain in vivo surface information of plant leaves by imaging replicas with SEM that is rapid and non-invasive. Dental putty was applied to the leaves for 5 minutes and then removed. Replicas were then imaged with SEM and compared to fresh leaves, and leaves that were processed conventionally by chemical fixation, dehydration and critical point drying. The surface structure of leaves was well preserved on the replicas. The outline of epidermal as well as guard cells could be clearly distinguished enabling determination of stomatal density. Comparison of the dimensions of guard cells revealed that replicas did not differ from fresh leaves, while conventional sample preparation induced strong shrinkage (-40% in length and -38% in width) of the cells when compared to guard cells on fresh leaves. Tilting the replicas enabled clear measurement of stomatal aperture dimensions. Summing up, the major advantages of this method are that it is inexpensive, non-toxic, simple to apply, can be performed in the field, and that results on stomatal density and in vivo stomatal dimensions in 3D can be obtained in a few minutes.
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Affiliation(s)
| | - Jonathan Schmidt
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Joseph D. White
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, Texas, United States of America
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