Evidence for a physiological gradient in the vestimentiferan trophosome: size–frequency analysis of bacterial populations and trophosome chemistry

1986 ◽  
Vol 64 (5) ◽  
pp. 1095-1103 ◽  
Author(s):  
M. E. de Burgh
Keyword(s):  
Chemical Analysis ◽  
Frequency Analysis ◽  
Hydrothermal Vents ◽  
Bacterial Symbiont ◽  
Posterior Region ◽  
Bacterial Symbionts ◽  
Bacterial Populations ◽  
Minor Elements ◽  
Bacterial Division ◽  
Bulk Chemical

Size of bacterial symbionts was compared in anterior and posterior trophosome tissue of four vestimentiferan worm species from hydrothermal vents. Analysis of size measurements indicated that there were more small bacteria in the anterior than the posterior trophosome. Bacterial division, though rarely seen, was more common in the anterior trophosome. Bulk chemical analysis of the two trophosome regions showed that sulfur (essential in the bacterial symbiont metabolism) and zinc were more concentrated in the anterior tissues, whereas 31 other major and minor elements were more concentrated in the posterior region. The existence and significance of a physiological gradient in the vestimentiferan trophosome is discussed.

scholarly journals Effects of photofunctionalization on early osseointegration of titanium dental implants in the maxillary posterior region: a randomized double-blinded clinical trial

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Bada Choi ◽  
Ye Chan Lee ◽  
Kyung Chul Oh ◽  
Jae Hoon Lee
Keyword(s):  
Clinical Trial ◽  
Resonance Frequency ◽  
Bone Quality ◽  
Frequency Analysis ◽  
Treated Group ◽  
Posterior Region ◽  
Resonance Frequency Analysis ◽  
Group Iii ◽  
The Stability ◽  
Double Blinded

Abstract Background This study aimed to investigate the effects of ultraviolet (UV) photofunctionalization on the stability of implants during the early phase in the posterior region of the maxilla. The study was a randomized double-blinded clinical trial. Half of the participants received conventional commercial implants while the other half received UV-irradiated implants. The surgical sites were classified into three bone quality groups (II, III, IV) based on the grayscale value measured on cone-beam computed tomography. The values obtained from resonance frequency analysis were recorded immediately after implant placement and at 4 weeks and at 4 months postoperatively. The marginal bone level of the implants was evaluated using periapical radiographs at 4 weeks, 4 months, and 1 year postoperatively. Results Fifty-seven implants placed in 34 participants were analyzed in this study. In group III, significant differences were observed in terms of the differences of resonance frequency analysis values at 4 weeks (p = 0.004) and 4 months (p = 0.017) postoperatively. In group II, the UV-treated group showed significantly lesser bone loss at 4 weeks post-operatively (p = 0.037). Conclusions Within the limitation of the present study, we concluded that UV surface treatment on implants may increase the initial stability in the region of the maxilla with poor bone quality.

scholarly journals Dual symbiosis in the deep-sea hydrothermal vent snail Gigantopelta aegis revealed by its hologenome

2020 ◽  
Author(s):  
Yi Lan ◽  
Jin Sun ◽  
Chong Chen ◽  
Yanan Sun ◽  
Yadong Zhou ◽  
...  
Keyword(s):  
Deep Sea ◽  
Hydrothermal Vent ◽  
Hydrothermal Vents ◽  
Snail Host ◽  
Bacterial Symbionts ◽  
Mutualistic Relationship ◽  
Genomic Studies ◽  
Similar Depth ◽  
Selection Of ◽  
Chromosome Level

AbstractAnimals endemic to deep-sea hydrothermal vents often form obligatory relationships with bacterial symbionts, maintained by intricate host-symbiont interactions. Endosymbiosis with more than one symbiont is uncommon, and most genomic studies focusing on such ‘dual symbiosis’ systems have not investigated the host and the symbionts to a similar depth simultaneously. Here, we report a novel dual symbiosis among the peltospirid snail Gigantopelta aegis and its two Gammaproteobacteria endosymbionts – one being a sulphur oxidiser and the other a methane oxidiser. We assembled high-quality genomes for all three parties of this holobiont, with a chromosome-level assembly for the snail host (1.15 Gb, N50 = 82 Mb, 15 pseudo-chromosomes). In-depth analyses of these genomes reveal an intimate mutualistic relationship with complementarity in nutrition and metabolic codependency, resulting in a system highly versatile in transportation and utilisation of chemical energy. Moreover, G. aegis has an enhanced immune capability that likely facilitates the possession of more than one type of symbiont. Comparisons with Chrysomallon squamiferum, another chemosymbiotic snail in the same family but only with one sulphur-oxidising endosymbiont, show that the two snails’ sulphur-oxidising endosymbionts are phylogenetically distant, agreeing with previous results that the two snails have evolved endosymbiosis independently and convergently. Notably, the same capabilities of biosynthesis of specific nutrition lacking in the host genome are shared by the two sulphur-oxidising endosymbionts of the two snail genera, which may be a key criterion in the selection of symbionts by the hosts.

The preparation of silicate compositions by a gelling method

1968 ◽  
Vol 36 (282) ◽  
pp. 832-838 ◽  
Author(s):  
D. L. Hamilton ◽  
C. M. B. Henderson
Keyword(s):  
Chemical Composition ◽  
Chemical Analysis ◽  
Bulk Chemical Composition ◽  
Weight Yield ◽  
Bulk Chemical

SummaryA method for the preparation of chemically homogeneous powders by a weighing and gelling technique is described in detail. Stress is placed on the importance of the weight yield as an indication of the bulk chemical composition and on the chemical analysis of several portions to test the homogeneity. A list of recommended chemicals is included in an appendix.

The Influence of Structure on Ba and K Uptake by a Synthetic Phyllomanganate

Clay Minerals ◽  
1994 ◽  
Vol 29 (2) ◽  
pp. 215-222 ◽  
Author(s):  
E. Paterson ◽  
R. Swaffield ◽  
L. Clark
Keyword(s):  
Chemical Analysis ◽  
Cation Exchange ◽  
Exchange Reaction ◽  
Charge Distribution ◽  
Photoelectron Spectroscopy ◽  
Basal Spacing ◽  
K Uptake ◽  
Selective Uptake ◽  
X Ray ◽  
Bulk Chemical

AbstractThe uptake of Ba2+ and K+ by a synthetic Na-phyllomanganate has been studied by chemical analysis, X-ray diffractometry and X-ray photoelectron spectroscopy. The changes in basal spacing arising from cation exchange have been used to monitor the progress of the exchange reaction and confirm the selectivity measured by bulk chemical analysis. However, the selective uptake of Ba2+ over Ca2+ is much greater than that of K+ over Na+ and it is suggested that charge distribution in the interlayer is important. The results are discussed in the light of recent advances in our understanding of the phyllomanganate structure.

Inter-technique comparison of PIXE and XRF for lake sediments

2018 ◽  
Vol 33 (5) ◽  
pp. 883-892 ◽  
Author(s):  
M. El Ouahabi ◽  
G. Chêne ◽  
D. Strivay ◽  
J. Vander Auwera ◽  
A. Hubert-Ferrari
Keyword(s):  
Chemical Analysis ◽  
Lake Sediments ◽  
Major Elements ◽  
Minor Elements ◽  
Validation Procedure ◽  
Technique Comparison

In this paper we describe a validation procedure for the chemical analysis of major elements and some minor elements such as Sr, Cr, Ni, Zn and Zr in heterogeneous geological sediments.

Antimicrobial Activity of Marine Bacterial Symbionts Retrieved from Shallow Water Hydrothermal Vents

2016 ◽  
Vol 18 (3) ◽  
pp. 293-300 ◽  
Author(s):  
Arnheidur Eythorsdottir ◽  
Sesselja Omarsdottir ◽  
Hjorleifur Einarsson
Keyword(s):  
Antimicrobial Activity ◽  
Shallow Water ◽  
Hydrothermal Vents ◽  
Bacterial Symbionts

Isolation and partial chemical analysis of firmly bound exopolysaccharide from adherent cells of a freshwater sediment bacterium

1985 ◽  
Vol 31 (8) ◽  
pp. 675-680 ◽  
Author(s):  
R. M. Platt ◽  
G. G. Geesey ◽  
J. D. Davis ◽  
D. C. White
Keyword(s):  
Chemical Analysis ◽  
Ultrastructural Level ◽  
Freshwater Sediment ◽  
Culture Vessel ◽  
Adherent Cells ◽  
Natural Sediment ◽  
Bacterial Populations ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Wall Components ◽  
Partial Chemical

Cells of a freshwater sediment bacterium produced firmly bound extracellular polymers in laboratory cultures which, at the ultrastructural level, resembled those produced by natural sediment bacterial populations. Production of the exopolymers during subculture was maintained by using as a source of inoculum the population of cells which adhered to each other and to the wall of the glass culture vessel. The exopolymers were selectively released from the cells by blending and centrifugation in the presence of EDTA. Evaluation of glucose-6-phosphate dehydrogenase activity and 2-keto-3-deoxyoctonate concentration indicated that only small amounts of intracellular and cell wall components were released from the cells during exopolymer removal. Chemical analysis of the isolated crude exopolymer material indicated that it contained protein, polysaccharide, and DNA. The treatment promoted the selective isolation of firmly bound polymers from the surface of adherent cells.

Mechanisms of specificity of association between the nematode Steinernema scapterisci and its symbiotic bacterium

Parasitology ◽  
1997 ◽  
Vol 114 (5) ◽  
pp. 483-488 ◽  
Author(s):  
P. S. GREWAL ◽  
M. MATSUURA ◽  
V. CONVERSE
Keyword(s):  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Symbiotic Bacterium ◽  
Bacterial Symbiont ◽  
Steinernema Carpocapsae ◽  
Infective Juvenile ◽  
Symbiotic Bacteria ◽  
Bacterial Symbionts ◽  
First Report ◽  
Successful Isolation

We suggest a new mechanism for the maintenance of specificity of the association between the entomopathogenic nematode Steinernema scapterisci and its symbiotic bacteria. We evaluated the development and reproduction of infective and non-infective juvenile S. scapterisci in monoxenic combinations with its symbiotic bacteria, Xenorhabdus sp. ‘S’ and with the bacterial symbiont of Steinernema carpocapsae and Steinernema riobravis. Although development of non-infective stages occurred on all Xenorhabdus spp., the development of infective juveniles to the 4th stage (‘dauer’ recovery) was significantly delayed and reduced with X. nematophilus and Xenorhabdus sp. ‘R’, the bacterial symbionts of S. carpocapsae and S. riobravis, respectively. ‘Dauer’ recovery improved significantly when the cultures of X. nematophilus and Xenorhabdus sp. ‘R’ were supplemented with cell-free filtrates from Xenorhabdus sp. ‘S’. The infective juvenile S. scapterisci produced in all 3 cultures were virulent to Galleria mellonella larvae, confirming successful retention of Xenorhabdus from other steinernematids in their intestine. In fact, S. scapterisci infective juveniles containing X. nematophilus or Xenorhabdus sp. ‘R’ were more virulent to G. mellonella than those containing their natural symbiont, Xenorhabdus sp. ‘S’. We believe that this is the first demonstration of the symbiont-specific exit of infective juveniles from the ‘dauer’ phase which represents the finest level of specificity of bacteria–nematode association. This is also the first report of successful isolation of the natural symbiont of S. scapterisci.

scholarly journals SPLOTCH, A PHYSIOLOGICAL LEAF DISEASE OF WHEAT: I. NUTRITIONAL STUDIES

1962 ◽  
Vol 42 (3) ◽  
pp. 403-414 ◽  
Author(s):  
B. J. Sallans ◽  
R. D. Tinline
Keyword(s):  
Chemical Analysis ◽  
Total Nitrogen ◽  
Minor Elements ◽  
Leaf Disease ◽  
Golden Ball ◽  
Nutritional Studies ◽  
Manganese Magnesium ◽  
Phosphatic Fertilizers

A leaf disease observed in Golden Ball and other durum wheats for a number of years is described and named splotch. It was reproduced in the greenhouse by growing these varieties in nitrogen-deficient soils and was reduced or prevented by the use of nitrate fertilizers. Chemical analysis of leaves demonstrated that splotch increased as the total nitrogen decreased below 4 per cent. Phosphatic fertilizers were found to influence splotch, sometimes increasing it, especially where yields were increased, and at other times decreasing it. Their effects are considered to be indirect and related to the ratio of nitrogen to phosphorus. The addition of the minor elements boron, manganese, magnesium, iron, zinc, molybdenum, and copper to the soil as a mixture increased splotch.

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