scholarly journals The emission of corrosive vapours by wood. Hot - water - extracted O - acetylated hemicelluloses from sweet chestnut (Castanea sativa) and wych elm (Ulmus glabrau) and a discussion of O-acetyl-group changes occurring in these woods during incubation at 48° and 100% relative humidity

1969 ◽  
Vol 113 (2) ◽  
pp. 253-257
Author(s):  
G. C. Cochrane ◽  
J. D. Gray ◽  
P. C. Arni

1. O-Acetylated polysaccharides were obtained from green wood of both sweet chestnut and wych elm by treatment of the residue remaining after dimethyl sulphoxide extraction with water at 98°. This gives a mixture of polysaccharides containing xylose, galactose, glucose and uronic acids. Analysis of these and their fractionated products suggest that only xylans in green sweet chestnut and green wych elm are O-acetylated. 2. The isolated O-acetylated xylans are not representative of the total O-acetylated xylans occurring in sweet chestnut and wych elm. 3. Application of the method developed by Bouveng for the location of O-acetyl groups to all four O-acetylated xylans obtained in this series of investigations by dimethyl sulphoxide extraction showed that those from sweet chestnut and wych elm, under the same conditions of incubation, lost: 74·2 and 43·4% of acetyl groups respectively, at C-2; 58·0 and 28·5% of acetyl groups respectively at C-3; 41·8 and 82·2% of acetyl groups respectively at C-2 and C-3. 4. A consideration of electronic and steric factors indicates that there does not appear to be a purely chemical reason for the difference in loss of O-acetyl groups between sweet chestnut and wych elm. It is suggested that the location of O-acetylated xylans in the wood cell walls and the presence of extractive may play some part in this difference.

1969 ◽  
Vol 113 (2) ◽  
pp. 243-252 ◽  
Author(s):  
G. C. Cochrane ◽  
J. D. Gray ◽  
P. C. Arni

1. O-Acetylated 4-O-methylglucuronoxylans were isolated from sweet chestnut and wych elm, either green or incubated at 48° and 100% relative humidity for 36 weeks. 2. The chlorine–ethanolamine method of delignification resulted in a 50% loss of O-acetyl groups from green wych elm compared with an 18% loss from green sweet chestnut. 3. The acid–chlorite method gave an acceptable loss of O-acetyl groups in three cases, but incubated sweet chestnut showed a 44·6% loss. However, it is believed that this is due to the loss of simple O-acetylated xylose sugars resulting from glycosidic hydrolysis, rather than removal of O-acetyl groups by direct hydrolysis. Assuming that this occurs in a random manner, it is unlikely to have much structural significance. 4. Dimethyl sulphoxide extraction of chestnut holocellulose and elm holocellulose, green and incubated, yielded O-acetyl glucuronoxylans containing 10·2, 3·8, 13·1 and 7·7% O-acetyl groups respectively. 5. The location of these O-acetyl groups was determined by Bouveng's method in which phenyl isocyanate is used as a blocking group.


2017 ◽  
Vol 19 (2) ◽  
pp. 126-130
Author(s):  
Rifatun Hasanah ◽  
Setyowati Setyowati ◽  
Noor Tifauzah

Background:One of the efforts in preventing congenital food disease is by washing the cutlery perfectly. The cutlery used by patients with infectious diseases should be noted more, because it has a risk in disease transmission through cutlery. The process of washing the cutlery for infected patients in Queen Latifa Hospital use three compartement sink method with hot water, while the three compartement sink method with clorine solvent has never been tested. Purpose: Research was to determine the difference in the number of germs in the tool was washed using three compartement sink method with hot water and with clorine solvent. Method:Types of research is experiment with rancangan percobaan acak kelompok (RAK). The object of this research is 4 plates and 4 bowls. The number of experimental units in this research were 2 treatments x 2 cutlery x 2 checks x 2 reapetitions = 16 experimental units. The analysis used independent t-test with 95% confidence level. Result :The average number of germs in the cutlery washed using the three compartment sink method with hot water was 1 x 101 cfu / cm2, whereas with chlorine solvent is 0.2 cfu / cm2. Independent test t-test shows p = 0.049 which means the hypothesis is accepted. onclusion : There are differences in the number of germs in the washing cutlery using the three compartment sink method with hot water and with chlorine solvent.   Keywords: number of germs, cutlery, three compartment sink


2017 ◽  
Vol 19 (2) ◽  
pp. 126
Author(s):  
Rifatun Hasanah ◽  
Setyowati Setyowati ◽  
Noor Tifauzah

Background:One of the efforts in preventing congenital food disease is by washing the cutlery perfectly. The cutlery used by patients with infectious diseases should be noted more, because it has a risk in disease transmission through cutlery. The process of washing the cutlery for infected patients in Queen Latifa Hospital use three compartement sink method with hot water, while the three compartement sink method with clorine solvent has never been tested. Purpose: Research was to determine the difference in the number of germs in the tool was washed using three compartement sink method with hot water and with clorine solvent. Method:Types of research is experiment with rancangan percobaan acak kelompok (RAK). The object of this research is 4 plates and 4 bowls. The number of experimental units in this research were 2 treatments x 2 cutlery x 2 checks x 2 reapetitions = 16 experimental units. The analysis used independent t-test with 95% confidence level. Result :The average number of germs in the cutlery washed using the three compartment sink method with hot water was 1 x 101 cfu / cm2, whereas with chlorine solvent is 0.2 cfu / cm2. Independent test t-test shows p = 0.049 which means the hypothesis is accepted. Conclusion : There are differences in the number of germs in the washing cutlery using the three compartment sink method with hot water and with chlorine solvent.


1999 ◽  
Vol 64 ◽  
Author(s):  
D. Van den Meersschaut ◽  
B. De Cuyper ◽  
K. Vandekerkhove ◽  
N. Lust

Natural  stand changes in the forest reserve of Liedekerke were analysed during the  period    1986-1996, using a permanent grid of circular plots. The monitoring  concentrated on natural    changes in species composition, using stem number and basal area as  indicators, and changes    in spatial distribution and colonization capacities of trees and shrubs,  with special interest in the    competition between exotic and indigenous species. After only a decade of  monitoring important    natural changes in the woody layer were detected. The pioneer forest is  gradually maturing    through self-thinning processes and shifts in species composition. The  overall stem number    decreased with 33.6%, while the basal area increased with 20.9%. Birch (Betula pendula/    pubescens) and indigenous oak (Quercus robur/petraea) remained  dominant. More tolerant    exotic species, like red oak (Quercus rubra) and sweet chestnut (Castanea  sativa), are slowly    increasing their share in the species composition and expanding their  range. Pioneer species on    the other hand, like aspen (Populus tremula), willow (Salix  capreaicinerealaurita), alder buckthorn    (Frangula alnus) and  common (Alnus glutinosa)  and grey alder (A. incana),  strongly declined.    Black cherry (Prunus serotina) seems to be slowly invading the forest due to its  massive    natural regeneration. Strong competition may be expected especially from  rowan ash (Sorbus    aucuparia), which showed similar regeneration  and colonization capacities. Elder (Sambucus    nigra) dramatically extented its range, though  its share remains marginal. Beech remained absent    most probably due to the lack of mature trees in the vacinity of the  forest. Finally this    change detection allowed that general predictions could be made on the  future natural development    and composition of this forest reserve, which could serve forest management  decisions.


2021 ◽  
Vol 494 ◽  
pp. 119320
Author(s):  
Marco Conedera ◽  
Patrik Krebs ◽  
Eric Gehring ◽  
Jan Wunder ◽  
Lisa Hülsmann ◽  
...  

1983 ◽  
Vol 34 (3) ◽  
pp. 241 ◽  
Author(s):  
CW Ford

Stem cell walls of pangola grass (Digitaria decumbens) were ground to two particle sizes (c. 1 and 0.1 mm diameter), and incubated with cellulase (ex. Trichoderma viride) for varying times before and after delignification. Total cell walls finely ground (0.1 mm) with a Spex Shatterbox mill were initially degraded more rapidly (to 24 h) than delignified 1 mm particles. Thereafter the delignified material was solubilized to a greater extent. Subsequent specific determinations of cell wall polysaccharides indicated that delignification increased the rate of hemicellulose degradation to a greater extent than did particle size reduction, whereas the opposite was found for cellulose. The difference between delignified and Spex-ground residues, in terms of the amount of polysaccharide digested, was much greater for cellulose than hemicellulose. It is concluded that structural features play a more important role in limiting cellulase degradation of cellulose than does association with lignin, the reverse being so for hemicellulose.


Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1538
Author(s):  
Ana Teresa Alhinho ◽  
Miguel Jesus Nunes Ramos ◽  
Sofia Alves ◽  
Margarida Rocheta ◽  
Leonor Morais-Cecílio ◽  
...  

The sweet chestnut tree (Castanea sativa Mill.) is one of the most significant Mediterranean tree species, being an important natural resource for the wood and fruit industries. It is a monoecious species, presenting unisexual male catkins and bisexual catkins, with the latter having distinct male and female flowers. Despite the importance of the sweet chestnut tree, little is known regarding the molecular mechanisms involved in the determination of sexual organ identity. Thus, the study of how the different flowers of C. sativa develop is fundamental to understand the reproductive success of this species and the impact of flower phenology on its productivity. In this study, a C. sativa de novo transcriptome was assembled and the homologous genes to those of the ABCDE model for floral organ identity were identified. Expression analysis showed that the C. sativa B- and C-class genes are differentially expressed in the male flowers and female flowers. Yeast two-hybrid analysis also suggested that changes in the canonical ABCDE protein–protein interactions may underlie the mechanisms necessary to the development of separate male and female flowers, as reported for the monoecious Fagaceae Quercus suber. The results here depicted constitute a step towards the understanding of the molecular mechanisms involved in unisexual flower development in C. sativa, also suggesting that the ABCDE model for flower organ identity may be molecularly conserved in the predominantly monoecious Fagaceae family.


Author(s):  

Abstract A new distribution map is provided for Gnomoniopsis smithogilvyi Shuttleworth, Liew and Guest. Sordariomycetes: Diaporthales. Hosts: sweet chestnut (Castanea sativa) and other chestnut species. Information is given on the geographical distribution in Europe (France, Greece, Italy, mainland Italy, Sardinia, Slovenia, Spain Switzerland, UK, England and Wales), Asia (India, Jammu and Kashmir), Oceania (Australia, New South Wales, Victoria, New Zealand).


2017 ◽  
pp. 79-82
Author(s):  
Gabriella Kovács ◽  
László Radócz

The most destructive pathogen for the European chestnut is the blight fungus Cryphonectria parasitica (Murr.) Barr. The spread of the fungus was very fast in Europe within a few decades in the second half of the past century. During the tree-health checking in the chestnut andwalnut plantation in Romania, Hargita county, next to Homoródkarácsonyfalva village, we especially concentraded on the signs of blight disease occurrence. The grove is laying on a western slope, under a pine forest. This favourable geographical space protects it not only from pathogen attacts, but it has a special, mild microclimate for nut and chestnut trees. The European chestnut could be a valuable member of local forests, opening a new perspective under conditions of climate changes.


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