Effect of particle size and delignification on the rate of digestion of hemicellulose and cellulose by cellulase in mature pangola grass stems

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.

1990 ◽  
Vol 269 (2) ◽  
pp. 393-402 ◽  
Author(s):  
P Ryden ◽  
R R Selvendran

1. Polymers were solubilized from the cell walls of parenchyma from mature runner-bean pods with minimum degradation by successive extractions with cyclohexane-trans-1,2-diamine-NNN′N′-tetra-acetate (CDTA), Na2CO3 and KOH to leave the alpha-cellulose residue, which contained cross-linked pectic polysaccharides and Hyp-rich glycoproteins. These were solubilized with chlorite/acetic acid and cellulase. The polymers were fractionated by anion-exchange chromatography, and fractions were subjected to methylation analysis. 2. The pectic polysaccharides differed in their ease of extraction, and a small proportion were highly cross-linked. The bulk of the pectic polysaccharides solubilized by CDTA and Na2CO3 were less branched than those solubilized by KOH. There was good evidence that most of the pectic polysaccharides were not degraded during extraction. 3. The protein-containing fractions included Hyp-rich and Hyp-poor glycoproteins associated with easily extractable pectic polysaccharides, Hyp-rich glycoproteins solubilized with 4M-KOH+borate, the bulk of which were not associated with pectic polysaccharides, and highly cross-linked Hyp-rich glycoproteins. 4. Isodityrosine was not detected, suggesting that it does not have a (major) cross-linking role in these walls. Instead, it is suggested that phenolics, presumably linked to C-5 of 3,5-linked Araf residues of Hyp-rich glycoproteins, serve to cross-link some of the polymers. 5. There were two main types of xyloglucan, with different degrees of branching. The bulk of the less branched xyloglucans were solubilized by more-concentrated alkali. The anomeric configurations of the sugars in one of the highly branched xyloglucans were determined by 13C-n.m.r. spectroscopy. 6. The structural features of the cell-wall polymers and complexes are discussed in relation to the structure of the cell walls of parenchyma tissues.


2021 ◽  
Vol 5 (1) ◽  
pp. 104-110
Author(s):  
Tuti Rustiana ◽  
Dinar Rahayu

Vegetable oil in the cooking process usually is used multiple times to fry food. This process exposes the oil to heat and oxidation. The oil itself is lipid. Lipid is a triglyceride, which means three carboxylic acids are bonded to one molecule of glycerol to form of ester. Exposing triglyceride to heat and oxidation causes it to deteriorate and break into smaller molecules such as aldehyde, ketones, and hydrocarbons. This molecule causes rancidity. Rancidity can be measured in terms of the amount of hydroperoxide presents in oil in mEq of O2/Kg. The peroxides present oxidize the iodide to iodine and the iodine is then titrated to a colorimetric endpoint using sodium thiosulfate with starch as an indicator. The amount of iodine produced is directly proportional to the peroxide value. The research has been conducted to reduce the peroxide value of used cooking oil using adsorption. The adsorbent used here is activated charcoal with a concentration of 3% and particle size of 100 Mesh. Contact time with oil is varied, ranged from 30 to 90 minutes. Statistic treatment of t-student test is performed between peroxide value before and after treatment and it is found that the difference is significant. That means active charcoal can decrease peroxide value. One way of ANOVA test among contact times (30, 60, 90 minutes) proves there is no significant difference, leading to the conclusion that activated charcoal at 3% and particle size 100 Mesh can decrease the peroxide value of oil in only 30 minutes of contact time.


2005 ◽  
Vol 475-479 ◽  
pp. 2403-2406 ◽  
Author(s):  
Sang Mok Lee ◽  
Hoon Jae Park ◽  
Seung Soo Kim ◽  
Tae Hoon Choi ◽  
E.Z. Kim ◽  
...  

Reducing the particle size of drug materials down to submicron is an important matter in pharmaceutical industry. Cryogenic milling technology is one of the mechanical milling processes, which is mostly utilized in refining grain size of metal and ceramics at extremely low temperature environment. This technique has not been readily studied in application to medical and biotechnology. This paper, therefore, describes the application of cryogenic milling process to reduce particle size of Ibuprofen. The shape and size of the Ibuprofen particle before and after the cryogenic ball milling process were analyzed. XRD analysis was performed to examine a change in crystallinity of Ibuprofen by the cryogenic ball milling process. The results showed that the size of Ibuprofen particles was reduced to 1/10 or less of its initial size. The results also showed that the degree of crystallinity of Ibuprofen was slightly reduced after cryogenic ball milling with nitrogen.


2012 ◽  
Vol 12 (3) ◽  
pp. 279-286 ◽  
Author(s):  
Nuryono Nuryono ◽  
Ali Agus ◽  
Sri Wedhastri ◽  
Y.M.S. Maryudhani ◽  
Deni Pranowo ◽  
...  

A study on adsorption of AFB1 in corn (kernel and grained) on natural zeolite and bentonite has been investigated. The first work was adsorption in a batch system of standard AFB1 solution on adsorbents. Some factors such as contact time, concentration of AFB1 and particle size of adsorbent were evaluated. The amount of AFB1 adsorbed was calculated based on the difference of AFB1 concentration before and after adsorption determined by high performance liquid chromatography (HPLC) method. Adsorption of AFB1 in corn sample was emphasized by mixing aqueous suspension of sample with adsorbent. Concentration of AFB1 in suspension was analyzed by enzyme-linked immuno-sorbent assay (ELISA) method. Result shows that adsorption of AFB1 on adsorbents of natural zeolite and bentonite is very fast. Within 15 min 99% of AFB1 (200 ng/mL) has been adsorbed by 25 mg of bentonite and 96% by zeolite. The particle size higher than 200 mesh did not give significant effect on the AFB1 adsorption capability. Effectiveness of zeolite in adsorbing AFB1 is lower than that of bentonite. Capability in reducing AFB1 contamination in corn samples (kernel and meal) for both adsorbents is lower than that in standard solution.


2006 ◽  
Vol 19 (12) ◽  
pp. 1420-1430 ◽  
Author(s):  
Harrold A. van den Burg ◽  
Stuart J. Harrison ◽  
Matthieu H. A. J. Joosten ◽  
Jacques Vervoort ◽  
Pierre J. G. M. de Wit

Resistance against the leaf mold fungus Cladosporium fulvum is mediated by the tomato Cf proteins which belong to the class of receptor-like proteins and indirectly recognize extracellular avirulence proteins (Avrs) of the fungus. Apart from triggering disease resistance, Avrs are believed to play a role in pathogenicity or virulence of C. fulvum. Here, we report on the avirulence protein Avr4, which is a chitin-binding lectin containing an invertebrate chitin-binding domain (CBM14). This domain is found in many eukaryotes, but has not yet been described in fungal or plant genomes. We found that interaction of Avr4 with chitin is specific, because it does not interact with other cell wall polysaccharides. Avr4 binds to chitin oligomers with a minimal length of three N-acetyl glucosamine residues. In vitro, Avr4 protects chitin against hydrolysis by plant chitinases. Avr4 also binds to chitin in cell walls of the fungi Trichoderma viride and Fusarium solani f. sp. phaseoli and protects these fungi against normally deleterious concentrations of plant chitinases. In situ fluorescence studies showed that Avr4 also binds to cell walls of C. fulvum during infection of tomato, where it most likely protects the fungus against tomato chitinases, suggesting that Avr4 is a counter-defensive virulence factor.


Author(s):  
R.A. Herring

Rapid thermal annealing (RTA) of ion-implanted Si is important for device fabrication. The defect structures of 2.5, 4.0, and 6.0 MeV As-implanted silicon irradiated to fluences of 2E14, 4E14, and 6E14, respectively, have been analyzed by electron diffraction both before and after RTA at 1100°C for 10 seconds. At such high fluences and energies the implanted As ions change the Si from crystalline to amorphous. Three distinct amorphous regions emerge due to the three implantation energies used (Fig. 1). The amorphous regions are separated from each other by crystalline Si (marked L1, L2, and L3 in Fig. 1) which contains a high concentration of small defect clusters. The small defect clusters were similar to what had been determined earlier as being amorphous zones since their contrast was principally of the structure-factor type that arises due to the difference in extinction distance between the matrix and damage regions.


1979 ◽  
Vol 42 (04) ◽  
pp. 1332-1339 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Takeshi Motomiya ◽  
Minoru Sonoda ◽  
Noboru Miyagawa

SummaryChanges in platelets in 48 patients with uterine myoma before and after hysterectomy with and without ovariectomy were examined. Bilateral ovariectomy in 25 cases (ovariec-tomized group) and unilateral or non-ovariectomy in 23 cases (control group) were performed at the hysterectomy. Platelet count and an appearance rate of secondary aggregation decreased at one day after and increased at one week after the operation, similarly in both the ovariectomized and the control group. The appearance rate of secondary aggregation was reflected in an intensity of aggregation at 5 min after the addition of reagent to PRP. At one month after the operation, the appearance rate of secondary aggregation induced by 3 μM ADP showed a statistically significant decrease in comparison with the preoperation value (P <0.05) and the enhancement of 5-min aggregation was still observed in the control group, while ceased in the ovariectomized group. The difference between the two groups was significant (P < 0.05). There was almost no change in the speed and intensity of primary and secondary aggregation during the observation period. No significant differences in collagen-induced aggregation were noted between the two groups. The results suggest that ovarian hormones, mainly estrogen, facilitate platelet activation which is mediated by the so-called secondary aggregation.


Author(s):  
Niken Setyaningrum ◽  
Andri Setyorini ◽  
Fachruddin Tri Fitrianta

ABSTRACTBackground: Hypertension is one of the most common diseases, because this disease is suffered byboth men and women, as well as adults and young people. Treatment of hypertension does not onlyrely on medications from the doctor or regulate diet alone, but it is also important to make our bodyalways relaxed. Laughter can help to control blood pressure by reducing endocrine stress andcreating a relaxed condition to deal with relaxation.Objective: The general objective of the study was to determine the effect of laughter therapy ondecreasing elderly blood pressure in UPT Panti Wredha Budhi Dharma Yogyakarta.Methods: The design used in this study is a pre-experimental design study with one group pre-posttestresearch design where there is no control group (comparison). The population in this study wereelderly aged over> 60 years at 55 UPT Panti Wredha Budhi Dharma Yogyakarta. The method oftaking in this study uses total sampling. The sample in this study were 55 elderly. Data analysis wasused to determine the difference in blood pressure before and after laughing therapy with a ratio datascale that was using Pairs T-TestResult: There is an effect of laughing therapy on blood pressure in the elderly at UPT Panti WredhaBudhi Dharma Yogyakarta marked with a significant value of 0.000 (P <0.05)


2020 ◽  
Vol 22 (3) ◽  
pp. 341-361
Author(s):  
Gonzalo Grau-Pérez ◽  
J. Guillermo Milán

In Uruguay, Lacanian ideas arrived in the 1960s, into a context of Kleinian hegemony. Adopting a discursive approach, this study researched the initial reception of these ideas and its effects on clinical practices. We gathered a corpus of discursive data from clinical cases and theoretical-doctrinal articles (from the 1960s, 1970s and 1980s). In order to examine the effects of Lacanian ideas, we analysed the difference in the way of interpreting the clinical material before and after Lacan's reception. The results of this research illuminate some epistemological problems of psychoanalysis, especially the relationship between theory and clinical practice.


1962 ◽  
Vol 41 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Pentti A. Järvinen ◽  
Sykkö Pesonen ◽  
Pirkko Väänänen

ABSTRACT The fractional determination of 17-ketosteroids in the daily urine was performed in nine cases of hyperemesis gravidarum and in four control cases, in the first trimester of pregnancy both before and after corticotrophin administration. The excretion of total 17-KS is similar in the two groups. Only in the hyperemesis group does the excretion of total 17-KS increase significantly after corticotrophin administration. The fractional determination reveals no difference between the two groups of patients with regard to the values of the fractions U (unidentified 17-KS), A (androsterone) and Rest (11-oxygenated 17-KS). The excretion of dehydroepiandrosterone is significantly higher in the hyperemesis group than in the control group. The excretion of androstanolone seems to be lower in the hyperemesis group than in the control group, but the difference is not statistically significant. The differences in the correlation between dehydroepiandrosterone and androstanolone in the two groups is significant. The high excretion of dehydroepiandrosterone and low excretion of androstanolone in cases of hyperemesis gravidarum is a sign of adrenal dysfunction.


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