scholarly journals On the Mechanism of Xylem Vessel Length Regulation

2004 ◽  
Vol 134 (1) ◽  
pp. 32-34 ◽  
Author(s):  
Jaap Nijsse
Keyword(s):  
Xylem Vessel ◽  
Vessel Length ◽  
Length Regulation

scholarly journals A semi-automated method for measuring xylem vessel length distribution

2020 ◽  
Vol 32 (4) ◽  
pp. 331-340
Author(s):  
Luciano Pereira ◽  
Marcela T. Miranda ◽  
Gabriel S. Pires ◽  
Vinícius S. Pacheco ◽  
Xinyi Guan ◽  
...  
Keyword(s):  
Length Distribution ◽  
Xylem Vessel ◽  
Vessel Length ◽  
Automated Method

Xylem vessel length and distribution: does analysis method matter? A study using Acacia

2017 ◽  
Vol 65 (3) ◽  
pp. 292 ◽  
Author(s):  
Virginia G. Williamson ◽  
John A. Milburn
Keyword(s):  
Hydraulic Conductivity ◽  
Xylem Vessel ◽  
Vessel Length ◽  
Carbon Particles ◽  
Spherical Carbon ◽  
India Ink ◽  
Transmission Electron ◽  
Length Data ◽  
Comparative Information ◽  
Global Datasets

Knowledge of xylem vessel length is important for several reasons, including the accurate calculation and comparison of hydraulic conductivity studies in excised stems. Vessel length data and distributions are also relevant in some anatomical, ecological, evolutionary, pathological and compatible hydraulic studies. However, determining vessel length is tedious, so is often either avoided or undertaken arbitrarily in hydraulic conductivity studies. We examined four injection media (paints and inks) under transmission electron microscopy to ascertain which was most suitable for determining vessel length. Hunt’s Speedball India ink, with evenly distributed, uniform spherical carbon particles of 33 nm, would avoid premature vessel blockage and, therefore, coupled with the fact that it is non-toxic, is the preferred medium to determine vessel length in Acacia amoena Wendl. terminal stems. The longest vessel was 10 cm, which accounted for 0.4% of vessels. Vessel length distributions were then determined and compared using the same dataset and four established methods. All four methods produced distributions which indicated that the most common vessel length class was short (0–2 cm), and no method was significantly different from the other; however, for ease of calculation, the Christman et al. (2009) method is recommended. Whether vessel length or distribution is necessary for hydraulic-conductivity studies will depend on whether or not merely indicative rates of flow are required, but to provide comparative information for global datasets, then they are needed.

A global analysis of xylem vessel length in woody plants

2012 ◽  
Vol 99 (10) ◽  
pp. 1583-1591 ◽  
Author(s):  
Anna L. Jacobsen ◽  
R. Brandon Pratt ◽  
Michael F. Tobin ◽  
Uwe G. Hacke ◽  
Frank W. Ewers
Keyword(s):  
Woody Plants ◽  
Global Analysis ◽  
Xylem Vessel ◽  
Vessel Length

Maximum-likelihood estimation of xylem vessel length distributions

2018 ◽  
Vol 455 ◽  
pp. 329-341 ◽  
Author(s):  
Roman M. Link ◽  
Bernhard Schuldt ◽  
Brendan Choat ◽  
Steven Jansen ◽  
Alexander R. Cobb
Keyword(s):  
Maximum Likelihood ◽  
Maximum Likelihood Estimation ◽  
Likelihood Estimation ◽  
Xylem Vessel ◽  
Vessel Length

1306: Techniques of Vascular Control and their Effects on Vessel Length

2004 ◽  
Vol 171 (4S) ◽  
pp. 344-344
Author(s):  
Jonathan E. Bernie ◽  
Chandru P. Sundaram,
Keyword(s):  
Vascular Control ◽  
Vessel Length

scholarly journals Rif1 regulates telomere length through conserved HEAT repeats

2021 ◽  
Vol 49 (7) ◽  
pp. 3967-3980
Author(s):  
Calla B Shubin ◽  
Rini Mayangsari ◽  
Ariel D Swett ◽  
Carol W Greider
Keyword(s):  
Dna Binding ◽  
Telomere Length ◽  
Functional Role ◽  
Conserved Residues ◽  
Binding Interface ◽  
Binding Function ◽  
Length Regulation ◽  
Telomere Length Regulation ◽  
Telomere Regulation ◽  
Conserved Amino Acids

AbstractIn budding yeast, Rif1 negatively regulates telomere length, but the mechanism of this regulation has remained elusive. Previous work identified several functional domains of Rif1, but none of these has been shown to mediate telomere length. To define Rif1 domains responsible for telomere regulation, we localized truncations of Rif1 to a single specific telomere and measured telomere length of that telomere compared to bulk telomeres. We found that a domain in the N-terminus containing HEAT repeats, Rif1177–996, was sufficient for length regulation when tethered to the telomere. Charged residues in this region were previously proposed to mediate DNA binding. We found that mutation of these residues disrupted telomere length regulation even when Rif1 was tethered to the telomere. Mutation of other conserved residues in this region, which were not predicted to interact with DNA, also disrupted telomere length maintenance, while mutation of conserved residues distal to this region did not. Our data suggest that conserved amino acids in the region from 436 to 577 play a functional role in telomere length regulation, which is separate from their proposed DNA binding function. We propose that the Rif1 HEAT repeats region represents a protein-protein binding interface that mediates telomere length regulation.

scholarly journals Effect of O-Antigen Chain Length Regulation on the Immunogenicity of Shigella and Salmonella Generalized Modules for Membrane Antigens (GMMA)

2021 ◽  
Vol 22 (3) ◽  
pp. 1309
Author(s):  
Gianmarco Gasperini ◽  
Maria Michelina Raso ◽  
Vanessa Arato ◽  
Maria Grazia Aruta ◽  
Paola Cescutti ◽  
...  
Keyword(s):  
Immune Response ◽  
Structural Characteristics ◽  
Antigen Delivery ◽  
Critical Quality Attributes ◽  
O Antigen ◽  
Alternative Approach ◽  
Length Regulation ◽  
Membrane Antigens ◽  
Glycoconjugate Vaccines ◽  
Work Supports

Recently, generalized modules for membrane antigens (GMMA) technology has been proposed as an alternative approach to traditional glycoconjugate vaccines for O-antigen delivery. Saccharide length is a well-known parameter that can impact the immune response induced by glycoconjugates both in terms of magnitude and quality. However, the criticality of O-antigen length on the immune response induced by GMMA-based vaccines has not been fully elucidated. Here, Shigella and Salmonella GMMA-producing strains were further mutated in order to display homogeneous polysaccharide populations of different sizes on a GMMA surface. Resulting GMMA were compared in mice immunization studies. Athymic nude mice were also used to investigate the involvement of T-cells in the immune response elicited. In contrast with what has been reported for traditional glycoconjugate vaccines and independent of the pathogen and the sugar structural characteristics, O-antigen length did not result in being a critical parameter for GMMA immunogenicity. This work supports the identification of critical quality attributes to optimize GMMA vaccine design and improve vaccine efficacy and gives insights on the nature of the immune response induced by GMMA.

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