Plasma lipids and lipoproteins of some members of the order Perissodactyla.

1. The plasma lipoproteins of various members of the order Perissodactyla have been examined by electrophoresis and analytical ultracentrifugation. 2. In the Equidae, high density (alpha) lipoprotein was the major component (80-90%) and low density (beta) lipoprotein (10-20%) the minor component. 3. In the Tapiridae represented by the Malayan tapir (Tapirus indicus), high density and low density lipoproteins were present in approximately equal amounts. 4. In the Rhinocerotidae, the high density lipoprotein characteristic of the Equidae and Tapiridae was absent, and the plasma lipoproteins consisted of a complex group having beta mobility on electrophoresis and a flotation pattern usually associated with low density lipoprotein. 5. The fatty acid composition of plasma lipids was remarkably similar in all members of the Perissodactyla examined, with very high percentages of linoleic acid (greater than 70%) being found in the cholesteryl esters.     

The occurrence of the hydrogenase in some blue-green algae

Several blue-green algae were surveyed for the occurrence of the hydrogenase which was assayed by the oxyhydrogen or Knallgas reaction in the intact organisms. In aerobically grown cultures, the reaction was detectable in Anabaena cylindrica, Nostoc muscorum and in two Anabaena variabilis species, whereas virtually no activity was observed in Anacystis nidulans and Cyanophora paradoxa. In these latter two algae, the reaction was, however, found after growth under molecular hydrogen for several days, which drastically increased the activity levels with all the algae tested. In the nitrogen fixing species, the activity of the Knallgas reaction was enhanced when all combined nitrogen was omitted from the media. H₂ and hydrogenase could not significantly support the CO₂-fixation in photoreduction experiments with all blue-green algae investigated here. Hydrogenase was assayed by the dithionite and methyl viologen dependent evolution of hydrogen and was found to be present with essentially the same specific activity levels in preparations of both heterocysts and vegetative cells from Anabaena cylindrica. Na₂S₂O₄ as well as H₂ supported the C₂H₂-reduction of the isolated heterocysts. The H₂-dependent C₂H₂-reduction did not require the presence of oxygen but was strictly light-dependent where H₂ served as an electron donor to photosystem I of these cells. It is concluded that hydrogen can be utilized by two different pathways in blue-green algae.Abbreviations Chl chlrophyll - CP creatine phosphate - CP kinase creatine phosphokinase - DCMU N-(3,4-dichlorophenyl)N,N-dimethylurea     

The occurrence order and cross-talk of different tRNA modifications

Chemical modifications expand the composition of RNA molecules from four standard nucleosides to over 160 modified nucleosides, which greatly increase the complexity and utility of RNAs. Transfer RNAs(tRNAs) are the most heavily modified cellular RNA molecules and contain the largest variety of modifications. Modification of tRNAs is pivotal for protein synthesis and also precisely regulates the noncanonical functions of tRNAs. Defects in tRNA modifications lead to numerous human diseases. Up to now, more than 100 types of modifications have been found in tRNAs. Intriguingly, some modifications occur widely on all tRNAs, while others only occur on a subgroup of tRNAs or even only a specific tRNA. The modification frequency of each tRNA is approximately 7% to 25%, with 5–20 modification sites present on each tRNA. The occurrence and modulation of tRNA modifications are specifically noticeable as plenty of interplays among different sites and modifications have been discovered. In particular, tRNA modifications are responsive to environmental changes, indicating their dynamic and highly organized nature. In this review, we summarized the known occurrence order, cross-talk, and cooperativity of tRNA modifications.     

Characterization of pseudogenes in members of the order Frankineae

Pseudogenes are defined as non-functional relatives of genes whose protein-coding abilities are lost and are no longer expressed within cells. They are an outcome of accumulation of mutations within a gene whose end product is not essential for survival. Proper investigation of the procedure of pseudogenization is relevant for estimating occurrence of duplications in genomes. Frankineae houses an interesting group of microorganisms, carving a niche in the microbial world. This study was undertaken with the objective of determining the abundance of pseudogenes, understanding strength of purifying selection, investigating evidence of pseudogene expression, and analysing their molecular nature, their origin, evolution and deterioration patterns amongst domain families. Investigation revealed the occurrence of 956 core pFAM families sharing common characteristics indicating co-evolution. WD40, Rve_3, DDE_Tnp_IS240 and phage integrase core domains are larger families, having more pseudogenes, signifying a probability of harmful foreign genes being disabled within transposable elements. High selective pressure depicted that gene families rapidly duplicating and evolving undoubtedly facilitated creation of a number of pseudogenes in Frankineae. Codon usage analysis between protein-coding genes and pseudogenes indicated a wide degree of variation with respect to different factors. Moreover, the majority of pseudogenes were under the effect of purifying selection. Frankineae pseudogenes were under stronger selective constraints, indicating that they were functional for a very long time and became pseudogenes abruptly. The origin and deterioration of pseudogenes has been attributed to selection and mutational pressure acting upon sequences for adapting to stressed soil environments.     

Synchronous short-term population fluctuations of some birds and mammals in Fennoscandia - occurrence and distribution

We examined population fluctuations of the voles Microtus agrestis L. and Clethrionomys glareolus Schreb. by biannual trapping; black grouse Tetrao tetrix L., mountain hare Lepus timidus L., and red fox Vulpes vulpes L. by using bag records from all over Sweden, questionnaires from south-central Sweden, and population indices from Grimsö Wildlife Research Area in south-central Sweden. Synchronous population fluctuations between voles as a group and the other species conformed to a 3–4 year periodic pattern in both autumn and spring populations only in northern and central Sweden (the boreal forest region). Spring populations of boreal forest grouse, hare, and probably also fox, lagged one year behind the voles. The northerly areas also formed geographical units of co-fluctuation within each game species. Using our own data as well as reviewing previous studies in Fennoscandia, we conclude that synchronized 3–4 year population fluctuations of voles and medium-sized herbivores are confined to the central and northern part of Fennoscandia, although voles may exhibit short-term population fluctuations further south. The synchronizing link between the herbivores could be (1) food plant quality and/or quantity and/or (2) predation. We could not reject either of these two plausible mechanisms as a cause of interspecifically synchronous fluctuations.     

The intramucosal distribution of gastric alcohol dehydrogenase and aldehyde dehydrogenase activity in rats

Using qualitative and microquantitative histochemical techniques, alcohol dehydrogenase and aldehyde dehydrogenase activity was studied in the gastric mucosa of male and female rats. Alcohol dehydrogenase was demonstrated by staining reactions with maximum activity in surface and neck cells and with clearly weaker activity also in parietal cells. Aldehyde dehydrogenase could be detected in surface and neck cells, and also to a comparable degree in the parietal cells. Quantitative analyses of microdissected samples yielded high values for alcohol dehydrogenase activity exclusively in the superficial part of the gastric mucosa, whereas low-K _m aldehyde dehydrogenase activity showed a decreasing gradient from the surface to the deeper parts of the mucosa. Sex differences could not be confirmed.Dedicated to Professor Dr. K.S. Ludwig on the occasion of his 70th birthday     

The Thai variant and the distribution of alleles of 6-phosphogluconate dehydrogenase and the distribution of glucose 6-phosphate dehydrogenase deficiency in Thailand

The samples were taken from 3185 subjects from ten provinces throughout Thailand. In 1577 males the frequency of glucose 6-phosphate dehydrogenase deficiency was 11.98%. In the far south the gene frequency was 2.83%; in the remainder of the country the frequency did not vary significantly about a mean of 13.76%. The deficiency is of a severe type. The G6PD of all of the nondeficient individuals had the electrophoretic mobility of type B. The mean frequency of the A/B electrophoretic phenotype of 6-phosphogluconate dehydrogenase is 8.47%. The maximum frequency was in central and southern Thailand with a decline to the north and northeast. A variant form of 6-PGD, referred to as the Thai variant, has been found in which two additional electrophoretic components migrate anodally to the normal A band, confirming that the molecule is at least a dimer. The hypothesis is advanced that erythrocyte 6-PGD is determined by two genetic loci, only one of which is translated in leukocytes.Supported by U.S. Army Contract DA-49-193 MD 2879, U.S.P.H.S. GM 09252, and U.S.P.H.S. 5-K3-GM-15325.     

The widespread occurrence and tissue distribution of the imidazolopyrazine luciferins

Bioluminescence has been reported to occur in 17 phyla and at least 700 genera. However, the luciferin chemistry of the majority of luminous organisms has yet to be determined. The most common chemistry which is known to occur in deep sea bioluminescence is imidazolopyrazine bioluminescence. The main aim of this study was to examine the phyletic and tissue distribution of imidazolopyrazine luciferins. This will facilitate analysis of imidazolopyrazine bioluminescence at the cellular and molecular levels and, in particular, how and when its chemistry is controlled and expressed in vivo. Assays for both known imidazolopyrazines were established and a range of fresh organisms and tissue were analysed, i.e. fish, cephalopods, copepods, ostracods, amphipods and euphausiids. The main findings were that the number of genera in which coelenterazine has been detected has been increased from 52 to about 90. Also, for the first time, the other known imidazolopyrazine luciferin,Vargula-type luciferin, was quantified in the ostracod Cypridina dentata, but was not detected in any of its potential predators. Neither imidazolopyrazine luciferin was found in several luminous stomiiform fish assayed. Coelenterazine was measured in the livers and photophores of a number of cephalopods and it is apparent that coelenterazine is responsible for both modes of luminescence. © 1997 John Wiley & Sons, Ltd.     

The distribution of geraniin and mallotusinic acid in the order geraniales

The distribution of geraniin and mallotusinic acid in Geraniaceae, Euphorbiaceae and other families in the Geraniales were investigated by HPLC. Geraniin composes the main part of the tannin in all of the investigated species of Geranium, but not in species of Pelargonium. The species of Geraniaceae lack mallotusinic acid. Geraniin was also detected in most of the species in the subfamily Euphorbioideae of Euphorbiaceae, although the amount was generally smaller than in Geranium, except for some woody species. Several species of Euphorbioideae contained mallotusinic acid. Characteristic of the subfamily Phyllanthoideae is the absence of mallotusinic acid and poor distribution of geraniin. Geraniin and mallotusinic acid were not detected in most of the species of other families in the Geraniales, except in Erythroxylum coca. Hyperin was found to be the main flavonol glycoside in most species of Geranium.     

The intramucosal distribution of gastric alcohol dehydrogenase and aldehyde dehydrogenase activity in rats.

Using qualitative and microquantitative histo-chemical techniques, alcohol dehydrogenase and aldehyde dehydrogenase activity was studied in the gastric mucosa of male and female rats. Alcohol dehydrogenase was demonstrated by staining reactions with maximum activity in surface and neck cells and with clearly weaker activity also in parietal cells. Aldehyde dehydrogenase could be detected in surface and neck cells, and also to a comparable degree in the parietal cells. Quantitative analyses of microdissected samples yielded high values for alcohol dehydrogenase activity exclusively in the superficial part of the gastric mucosa, whereas low-Km aldehyde dehydrogenase activity showed a decreasing gradient from the surface to the deeper parts of the mucosa. Sex differences could not be confirmed.     

The occurrence and activity of epithiospecifier protein in some cruciferae seeds

Epithiospecifier protein (ESP) activity was determined in the seeds of two cultivars of Brassica napus, in B. campestris and in Lepidium sativum. All four types of seeds contained susceptible substrates for ESP (that is, glucosinolates with terminal unsaturation in their side-chain), although L. sativum contained only a very small amount of one. Results suggest that Fe²⁺ is essential for ESP activity, but its presence certainly promoted the effects of ESP to a considerable extent, and even at a very low level (e.g. 6 × 10^?11 mol Fe²⁺. Further evidence was gained for the intramolecular nature of the reaction which results in cyanoepithioalkane formation.     

Characterization of some members of the genusThermomonospora

Twenty strains ofThermomonospora, isolated from the environments of patients with hypersensitivity pneumonitis or received from culture collections or other workers, were studied for their detailed morphological, physiological, and immunological characteristics. The species studied includedThermomonospora fusca, T. alba, T. curvata, T. mesophilia, andT. mesouviformis. The results indicate that several species can be differentiated by various criteria studied; however, two species,T. fusca andT. alba, could not be separated from one another by any of the tests or methods used in the study.     

The occurrence and subcellular localization of 3 -hydroxysteroid dehydrogenase in adult rat brain

The subcellular localization of 3α-hydroxysteroid dehydrogenase, the dependency of the rate of reaction on time, concentration of protein, cofactor requirements and the substrate stereospecificity were investigated in the adult rat brain. The $\text{in vitro}$ conversion of 3-keto-5β-cholanoic-24-¹⁴C acid to lithocholic acid was shown to occur in the cytosol without added cofactors. Incubation of ¹⁴C labeled 3α,7α-dihydroxy-5β-cholanoic and 3α,12α-dihydroxy-5β-cholanoic acids with adult rat brain cell-free preparations resulted in the production of less polar metabolites identified as 3-keto-7α-hydroxy-5β-cholanoic and 3-keto-12α-hydroxy-5β-cholanoic acids by TLC, GLC combined with a radioactive monitoring detection system and by cocrystallization to constant specific activity.