Synthesis of 5-O-β-D-galactofuranosyl-D-galactofuranose

Conversion of benzyl αβ-D-galactofuranoside into the 5,6-O-[α-(dimethyl-amino)benzylidene] derivative, followed by acetylation of HO-2 and HO-3, and selective ring opening or the acetal, gave benzyl 2,3-di-O-acetyl-6-O-benzoyl-αβ-D-galactofuranoside(4). The title disaccharide was synthesised from4 by reaction with 3,4,6-tri-O-acetyl-α-D-galactofuranose 1,2-(methyl orthoacetate) followed by removal of protecting groups     

Synthesis of 4-O-β-D-mannopyranosyl-L-rhamnopyranose

The title disaccharide (16) has been synthesized in 50% overall yield by way of condensation of 4,6-di-O-acetyl-2,3-O-carbonyl-α-D-mannopyranosyl bromide 5 with methyl 2,3-O-isopropylidene-α-L-rhamnopyranoside (1) in chloroform solution, in the presence of silver oxide. The disaccharide was characterized as the crystalline isopropyl alcoholate of methyl 4-O-β-D-mannopyranosyl-α-L-rhamnopyranoside (11) and as 1,2,3-tri-O acetyl-4-O- (2,3,4,6-tetra-O-acetyl-β-D-mannopyranosyl)-α-L-rhamnopyranose (15). Methyl β-D-mannopyranoside isopropyl alcoholate 7 was readily obtained in 85% yield via the reaction of bromide 5 with methanol.Reduction of 2,3-di-O-methyl-L-rhamnose with sodium borohydride, followed by acetylation, may result in the formation of an appreciable proportion of a boric ester, namely 1,5-di-O-acetyl-4-deoxy-2,3-di-O-methyl-L-rhamnitol-4-yl dimethyl borate, depending on the procedure used.     

Derivatives of β-D-fructofuranosyl α-D-galactopyranoside

De-etherification of 6,6′-di-O-tritylsucrose hexa-acetate (2) with boiling, aqueous acetic acid caused 4→6 acetyl migration and gave a syrupy hexa-acetate 14, characterised as the 4,6′-dimethanesulphonate 15. Reaction of 2,3,3′4′,6-penta-O-acetylsucrose (5) with trityl chloride in pyridine gave a mixture containing the 1′,6′-diether 6 the 6′-ether 9, confirming the lower reactivity of HO-1′ to tritylation. Subsequent mesylation, detritylation, acetylation afforded the corresponding 4-methanesulphonate 8 1′,4-dimethanesulphonate 11. Reaction of these sulphonates with benzoate, azide, bromide, and chloride anions afforded derivatives of β-D-fructofuranosyl α-D-galactopyranoside (29) by inversion of configuration at C-4. Treatment of the 4,6′-diol 14 the 1,′4,6′-triol 5, the 4-hydroxy 1′,6′-diether 6 with sulphuryl chloride effected replacement of the free hydroxyl groups and gave the corresponding, crystalline chlorodeoxy derivatives. The same 4-chloro-4-deoxy derivative was isolated when the 4-hydroxy-1′,6′-diether 6 was treated with mesyl chloride in N,N-dimethylformamide.     

Trichomonasfetus—Induced abortion

$\text{History}$ and $\text{Clinical}$$\text{Signs}$: Herds infected with $\text{Trichomonas}$$\text{fetus}$ have histories of infertility, occasional abortions, and pyometra.$\text{Gross}$$\text{Lesions}$: There are no specific gross lesions in the fetus. The fetuses are usually aborted in the first half of gestation and may or may not be accompanied by the placenta.$\text{Microscopic}$$\text{Lesions}$: There are no specific microscopic lesions.$\text{Cultural}$$\text{Procedures}$: It is ordinarily not necessary to culture $\text{T.}$$\text{fetus}$ in order to demonstrate its presence in placental fluids and/or abomasal contents.$\text{Serologic}$$\text{Procedures}$: There are no suitable seroligic procedures for diagnosing Trichomoniasis.$\text{Special}$$\text{Procedures}$: Wet mounts of abomasal contents and/or placental fluids are examined microscopically for $\text{T.}$$\text{fetus}$.$\text{Preferred}$$\text{Diagnostic}$$\text{Procedures}$: Demonstrate the presence of $\text{T.}$$\text{fetus}$ by microscopic examination of wet mounts of placental fluids and/or abomasal contents.     

Synthesis of 5-O-α-and-β-d-glucopyranosyl-d-glucofuranose and 5-O-α-d-glucopyranosyl-d-fructopyranose (leucrose)

Reaction of 1,2-O-cyclopentylidene-α-d-glucofuranurono-6,3-lactone (2) with 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide (1) gave 1,2-O-cyclopentylidene- 5-O-(2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl)-α-d-glucofuranurono-6,3-lactone (3, 45%) and 1,2-O-cyclopentylidene-5-O-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)-α-d-glucofuranurono-6,3-lactone (4, 38%). Reduction of 3 and 4 with lithium aluminium hydride, followed by removal of the cyclopentylidene group, afforded 5-O-α-(9) and -β-d-glucopyranosyl-d-glucofuranose (12), respectively. Base-catalysed isomerization of 9 yielded crystalline 5-O-α-d-glucopyranosyl-d-fructopyranose (leucrose, 53%).     

Invivo and invitro studies of 15α-hydroxyprogesterone in the human placenta

Studies were conducted to determine the fate of 15α-hydroxyprogesterone in human placental tissue. Tritiated 15α-hydroxyprogesterone was perfused through normal human placentas $\text{in situ}$ at the time of Cesarean section and incubated with a 10,000x g microsomal supernate of the placenta $\text{in vitro}$. In both systems the substrate, but no additional metabolites were identified. These findings indicate that 15α-hydroxyprogesterone is not metabolized during its passage in the human term placenta, and suggests that because of its fetal origin clinical measurements of 15α-hydroxyprogesterone may provide a valuable index to the status of fetal viability.     

Chemical Syntheses of 4-O-α and -β-D-galactopyranosyl-D-galactose and 3-O-α- and -β-D-galactopyranosyl-D-galactose

Reaction of 2,3-di-O-acetyl-1,6-anhydro-β-D-galactopyranose (2) with 2,3,4,6-tetra- O-acetyl-α-D-galactopyranosyl bromide in the presence of mercuric cyanide and subsequent acetolysis gave 1,2,3,6-tetra-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl)-α-D-galactopyranose (4, 40%) and 1,2,3,6-tetra-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl)-α-D-galactopyranose (5, 30%). Similarly, reaction of 2,4-di-O-acetyl-1,6-anhydro-β-D-galactopyranose (3) gave 1,2,4,6-tetra-O-acetyl-3-O-(2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl)-α-D-galactopyranose (6, 46%) and 1,2,4,6-tetra-O-acetyl-3-O-(2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl)-α-D-galactopyranose (7, 14%). The anomeric configurations of 4-7 were assigned by n.m.r. spectroscopy. Deacetylation of 4-7 afforded 4-O-α-D-galactopyranosyl-D-galactose (8), 4-O-β-D-galactopyranosyl-D-galactose (9), 3-O-α-D-galactopyranosyl-D-galactose (10), and 3-O-β-D-galactopyranosyl-D-galactose (11), respectively.     

?2\sqrt 2 Rule for Controlling the Tree Pattern in Forest Cut

A forest’s productivity can be optimized by the application of rules derived from monopolized circles. A monopolized circle is defined as a circle whose center is a tree and whose radius is half of the distance between the tree itself and its nearest neighbor. Three characteristics of monopolized circle are proved. (1) Monopolized circles do not overlay each other, the nearest relationship being tangent. (2) “Full uniform pattern” means that the grid of trees (a×b=N) covers the whole plot, so that the distance between each tree in a row is the same as the row spacing. The total monopolized circle area with a full uniform pattern is independent on the number of trees and times the plot area. (3) If a tree is removed, the area of some trees’ monopolized circle will increase without decreasing the monopolized circles of the other trees. According to the above three characteristics, “uniform index” is defined as the total area of monopolized circles in a plot divided by the total area of the monopolized circles, arranged in a uniform pattern in the same shaped plot. According to the definition of monopolized circle, the distribution of uniform index for a random pattern and the variance of L is . It is evident that E(L) is independent on N and the plot area; hence, L is a relative index. L can be used to compare the uniformity among plots with different areas and the numbers of trees. In a random pattern, where L is equivalent to the tree density of the plot in which the number of trees is 1 and the area is π, the influence of tree number and plot area to L is eliminated. When n→∞, D(L)→0 and it indicates that the greater the number of tree is in the plots, the smaller the difference between the uniform indices will be. There are three types of patterns for describing tree distribution (aggregated, random, and uniform patterns). Since the distribution of L in the random pattern is accurately derived, L can be used to test the pattern types. The research on Moarshan showed that the whole plot has an aggregated pattern; the first, third, and sixth parts have an aggregated pattern; and the second, fourth, and fifth parts have a random pattern. None of the uniform indices is more than 0.318 (1/∏), which indicates that uniform patterns are rare in natural forests. The rules of uniform index can be applied to forest thinning. If you want to increase the value of uniform index, you must increase the total area of monopolized circles, which can be done by removing select trees. “Increasing area trees” are the removed trees and can increase the value of the uniform index. A tree is an increasing area tree if the distance between the tree and its second nearest neighbor is times longer than that between the tree itself and its first nearest neighbor, which is called the rule. It was very interesting to find that when six plots were randomly separated from the original plot, the proportion of increasing area trees in each plot was always about 0.5 without exception. In random pattern, the expected proportion of increasing area trees is about 0.35–0.44, which is different from the sampling value of 0.5. The reason is very difficult to explain, and further study is needed. Two criteria can be used to identify which trees should be removed to increase the uniform index during forest thinning. Those trees should be (1) trees whose monopolized circle areas are on the small side and (2) increasing area trees, which are found via the rule. Translated from Acta Ecologica Sinica, 2005, 25(1) (in Chinese)     

Altered levels of β-endorphin fragments after chronic morphine treatment of guinea-pig ileum invitro and invivo

The isolated myenteric plexus-longitudinal muscle of the guinea-pig ilem (GPI) was used as testsystem to study the influence of chronic morphine treatment on the levels of enkephalins, β-endorphin and some of its fragments. The peptides were assayed by means of a combination of high pressure liquid chromatography and radioimmunoassays. It was found that the levels of methionine- and leucine-enkephalin and β-endorphin were not altered by chronic morphine treatment of guinea-pigs $\text{in}$$\text{vivo}$ nor in GPI exposed to morphine $\text{in}$$\text{vitro}$. However, the levels of some β-endorphin fragments i.c. γ-endorphin and des-tyrosine-γ-endorphin were elevated after morphine treatment $\text{in}$$\text{vitro}$ and $\text{in}$$\text{vivo}$ respectively. It is suggested that β-endorphin and its fragments are involved in homeostatic processes during development of opiate tolerance.     

α-D-Mannosidase-catalyzed hydrolysis of substituted phenyl α-D-mannopyranosides

The influence substituents on the hydrolysis of substituted phenyl α-D-mannopyranosides by α-D-mannosidase from Medicago sativa L. has been investigated. As indicated by structure-activity relations, the electronic effect of the substituent has an influence on the rate of formation of the intermediate mannosyl-enzyme complex. This effect depends not only on the nature of the substituent, but also on its position (meta or para) and on the temperature of the experiment. Hammett-type linear free energy relationships show that the reaction constant p changes its sign at ～27°. Substrates with strong electron-withdrawing groups show values of log V that are linearly related to 1/T, whereas the Arrhenius plots for other substrates are severely curved. This complex behaviour is tentatively explained by assuming that some meta-substituents have an unusual, temperature- and substituent-dependent influence on the formation of the Michaelis—Menten complex.     

GUIDE FOR AUTHORSOA

<正>Introduction Types of paper Contributions falling into the following categories will be considered for publication:original articles,review articles,short letters,modelling/theory and methods articles,rapid reports and special thematic issues.Please ensure that you select the appropriate article type from the list of options when making your submission.Authors contributing to special issues should ensure that they select the special issue article type from this list.     

GUIDE FOR AUTHORSOA

<正>Introduction Types of paper Contributions falling into the following categories will be considered for publication:original articles,review articles,short letters,modelling/theory and methods articles,rapid reports and special thematic issues.Please ensure that you select the appropriate article type from the list of options when making your submission.Authors contributing to special issues should ensure that they select the special issue article type from this list.     

GUIDE FOR AUTHORSOA

<正>Introduction Types of paper Contributions falling into the following categories will be considered for publication:original articles,review articles,short letters,modelling/theory and methods articles,rapid reports and special thematic issues.Please ensure that you select the appropriate article type from the list of options when making your submission.Authors contributing to special issues should ensure that they select the special issue article type from this list.