Synthesis of desmosterol and epidesmosterol from hyodeoxycholic acid

A new synthesis of desmosterol was described using hyodeoxycholic acid (3,6-dihydroxy-5β-cholanic acid) as a starting material. Epidesmosterol (3-hydroxycholesta-5,24-diene) was also synthesized for the first time from the same starting material.     

Adenine depurination and inactivation of plant ribosomes by an antiviral protein of Mirabilis jalapa (MAP)

Mirabilis antiviral protein (MAP) is a single-chain ribosome-inactivating protein (RIP) isolated from Mirabilis jalapa L. It depurinates the 28S-like rRNAs of prokaryotes and eukaryotes. A specific modification in the 25S rRNA of M. jalapa was found to occur during isolation of ribosomes by polyacrylamide/agarose composite gel electrophoresis. Primer extension analysis revealed the modification site to be at the adenine residue corresponding to A⁴³²⁴ in rat 28S rRNA. The amount of endogenous MAP seemed to be sufficient to inactivate most of the homologous ribosomes. The adenine of wheat ribosomes was also found to be removed to some extent by an endogenous RIP (tritin). However, the amount of endogenous tritin seemed to be insufficient for quantitative depurination of the homologous ribosomes.Endogenous MAP could shut down the protein synthesis of its own cells when it spreads into the cytoplasm through breaks of the cells. Therefore, we speculate that MAP is a defensive agent to induce viral resistance through the suicide of its own cells.     

Comparison of the intestinal bacteria in specific pathogen free mice from different breeders

Specific pathogen free BALB/c mice from 3 commercial laboratory animal breeders in Japan were compared on the composition of caecal flora revealed by selective and nonselective cultivation as well as direct microscopical observation on smears, and relative caecal weight. Large differences were detected in viable counts of total bacteria and almost all bacterial groups, while direct microscopical counts which consisted mainly of fusiform bacteria were almost equal, resulting in diverse recovery rates among 3 breeders. Eubacterium and spiral shaped organisms were not detected from all breeders. There also existed variations within breeders, especially those in the number of Enterobacteriaceae. Relative caecal weight also differed among breeders, suggesting the participation of variety of caecal bacteria in determining this parameter. As these variations in bacteriological status of animals can influence experimental results, standardization of intestinal microbial flora is required.     

Crossed inhibition as revealed by cross-correlogram between bilateral homonymous motor unit spikes in man.

Neuromuscular unit (NMU) spikes activated during the tonic vibration reflex (TVR) in man were studied by means of the cross-correlogram test. Those NMUs which preferredly fired at some definite interval with good correlation with vibration were called "locked" spikes. The amount above zero correlation level seen in the cross-correlogram was expressed as ipsilateral "excitatory frequency", Ef. TVR contraction of the ipsilateral quadriceps femoris muscle was stimulated by voluntary contraction of the contralateral quadriceps femoris. I. Cross-correlogram test of the contralateral voluntary NMU spikes with ipsilateral vibration revealed "contralateral inhibitory modulation". Such inhibitory modulation was observed in 24% of the contralateral NMUs during voluntary tracking contraction with visual feed-back and in 22% of NMUs during blind simulated contraction without visual feed-back. The "subtracted" amount, i.e., contralateral inhibitory modulation, was also expressed as the contralateral "inhibitory frequency", If, which was calculated from the indentations of the cross-correlogram. 2. When varied vibratory frequency was applied to the muscle both Ef and If attained their maximum value around an "optimal frequency" of vibration, i.e., 80-95 HZ. 3. The ratio Ef/If was proposed as the reciprocal co-activation ratio which was fairly independent of the change of vibratory frequency. An average value of Ef/If ratio was calculated at 2.2 +/- 0.9 from 19 experiments.     

Effects of lipolytic enzymes on the photochemical activities of spinach chloroplasts.

1. Spinach class II chloroplasts were treated with purified potato lipolytic acyl-hydrolase and venom phospholipase A2, and their lipid degradations and the effects on the photochemical activities were followed. 2. Potato lipolytic enzyme hydrolyzed monogalactosyldiacylglycerol at a faster rate than phospholipids such as phosphatidylglycerol and phosphatidylcholine. The treatment caused a rapid decrease of Photosystem I activity, and a less change of Photosystem II activity. 3. Venom phospholipase A2 which preferentially hydrolyzed phosphatidylglycerol, caused a rapid decrease of Photosystem II activity and only a slight decrease of photosystem I activity. 4. Potato enzyme and phospholipase A2 degraded the membrane lipids of glutaraldehyde-fixed chloroplasts at a rather slightly higher rate than those of non-treated chloroplasts. 5. The results suggested a possible correlation between monogalactosyldiacylglycerol degradation and decay of Photosystem I activity and between phosphatidylglycerol degradation and decay of Photosystem II activity. A possible mechanism is discussed.     

DNA strand scission by neocarzinostatin: molecular recognition process responsible for site-specificity

A series of hexanucleotides possessing A-T, G-C, inosine (I)-C and 2-aminoadenine (ANH2)-T base pairs at 5'-side of the target thymine were prepared and their selectivity for C-5' and C4' oxidation in the NCS-mediated degradation was investigated. Quantitative product analysis indicated that preferential C5' oxidation of deoxyribose moiety of the target T occurs at -5'-AT- and 5'-IT- sites, whereas C5' and C4' oxidation occurs competitively at T of -5'-GT- and -5'-ANH2T- sites. Based on the experimental results, an intercalation model that permits competitive hydrogen abstraction from C5' and C4' of deoxyribose moiety has been proposed.     

The transition in frequency of Y chromatin in males during the neonatal period

Summary The frequency of Y chromatin, visualized as fluorescent bodies in cell nuclei from lymphocytes in blood smears, was signficantly less in newborn males than in three-month-old male infants and adults. The frequency of Y chromatin-positive cells on day 0 was 36.16±9.11% and then increased daily. At one month after birth the frequency was 55.07±9.29%, which was not significantly different from that in adult males (57.08±5.97%).     

Analysis of the effects of snake venom proteinases on the activity of human plasma C1 esterase inhibitor, alpha 1-antichymotrypsin and alpha 2-antiplasmin

Incubation of C1 esterase inhibitor with Crotalid, Viperid and Colubrid snake venoms resulted in enzymatic inactivation of the inhibitor. Intact inhibitor (104 kDa) was converted into an active intermediate species of 89 kDa and then a further cleavage resulted in formation of an 86-kDa inactive inhibitor. In contrast, C1 esterase inhibitor did not lose activity during incubation with Elapid venoms; however, the intact inhibitor was gradually converted to an active species of 89 kDa during the incubation. Human alpha 1-antichymotrypsin was inactivated by all venoms tested, including those from the Elapid family. The 67-kDa intact inhibitor was converted by the venom proteinases to an inactive 63-kDa form. The results suggest that this acute-phase plasma protein is readily susceptible to inactivation by venom proteinases. Human alpha 2-antiplasmin (68 kDa) was cleaved to form a 61-kDa active intermediate, which then underwent a second cleavage to produce an inactive 53-kDa product. Elapid venoms had no effect on alpha 2-antiplasmin activity and did not cleave this inhibitor. All inhibitors were inactivated with catalytic amounts of venom proteinases. No stable proteinase-proteinase inhibitor complexes were detected, and no random proteolysis of the inhibitors occurred.     

Association of Allergic Symptoms with Dengue Infection and Severity: A Systematic Review and Meta-analysis

The relationship between the severity of dengue infection and allergy is still obscure. We conducted an electronic search across 12 databases for relevant articles reporting allergic symptoms, dengue infection, and dengue classification. These studies were categorized according to dengue severity and allergy symptoms, and a meta-analysis was performed by pooling the studies in each category. Among the included 57 articles, pruritus was the most common allergic sign followed by non-specified allergy and asthma(28.6%, 13%, and 6.5%, respectively). Despite the reported significant association of dengue with pruritus and total Ig E level(P \ 0.05), in comparison with non-dengue cases and healthy controls, there was no association between the different severe dengue group with pruritus, skin allergy, food allergy or asthma. However,removing the largest study revealed a significant association between asthma with dengue hemorrhagic fever(DHF) rather than dengue fever(DF). In comparison with DF, DHF was associated with Ig E positivity. Furthermore, specific-Ig E level was higher in secondary DF rather than primary DF. There was a possible association between allergy symptoms and dengue severity progression. Further studies are needed to clarify this association.