Haemagglutinating and Hydrophobic Properties of Corynebacterium (Eubacterium) Suis

Corynebacterium (Eubacterium) suis strains from boars and sows haemagglutinated erythrocytes of different animal species (calf, guinea pig, poultry, pig, and human). The haemaigglutination was man nose resistant (MR) and was neither inhibited by L-fucose nor D-galactose. The hydrophobicity measured by salt aggregation test (0.1–0.9 mol/1 (NH4)2SO4) and the hydrophobic interaction chromatography test (90 % retention in octyl sepharose) together with the haemagglutinating activity, indicated the presence of fimbriae on the bacteria. The haemagglutinating and hydrophobic properties were heat-sensitive (60°C for 10 min) suggestive of the presence of a protein structure. Two types of fimbria-tion were demonstrated by electron microscopy. Fetuin and glyco^ protein inhibited the haemagglutination, whereas porcine mucin was without any effect. These results indicate that branched glycoproteins might be important receptors for these fimbriae. The pathogenic aspects of C. suis are discussed, based on recent acquired knowledge of the effect of other pyelonephritogenic bacteria.     

Effects of beta 1- vs. beta 1- beta 2-blockade on training adaptations in rat skeletal muscle

The effect of selective vs. nonselective beta-blockade on fast-twitch [extensor digitorum longus (EDL)] and slow-twitch [soleus (SOL)] muscle enzyme activities following endurance training were characterized. Citrate synthase (CS), lactate dehydrogenase (LDH), and beta-hydroxyacyl-CoA dehydrogenase (HAD) activities were compared in SOL and EDL muscles of trained (T), metoprolol-trained (MT), propranolol-trained (PT), and sedentary (C) rats. Following 8 wk of treadmill running (1 h/day, 5 days/wk at approximately 30 m/min), LDH activity was depressed approximately 20% (P less than 0.05) in both SOL and EDL in only the PT rats, indicating inhibition of beta 2-mediated anaerobic glycolysis. EDL CS activity was similarly elevated in all three trained groups compared with sedentary controls. In SOL muscle, however, a drug attenuation effect was observed so that CS activity was increased only in the T (P less than 0.01) and MT (P less than 0.05) groups. HAD enzyme activity was increased somewhat (P less than 0.10) in SOL muscle in only the T group, but more so (P less than 0.05) in EDL in all three trained groups. The above findings suggest a training-induced selectivity effect not only with respect to beta 1-vs. beta 1-beta 2-blockers, but also with respect to muscle fiber type.     

Photosynthesis in intact leaves of C3 plants: Physics,physiology and rate limitations

The instantaneous rate of photosynthetic CO₂ assimilation in C₃ plants has generally been studied in model systems such as isolated chloroplasts and algae. From these studies and from theoretical analyses of gas exchange behavior it is now possible to study the biochemistry of photosynthesis in intact leaves using a combination of methods, most of which are nondestructive. The limitations to the rate of photosynthesis can be divided among three general classes: (1) the supply or utilization of CO₂, (2) the supply or utilization of light, and (3) the supply or utilization of phosphate. The first limitation is most readily studied by determining how the CO₂ assimilation rate varies with the partial pressure of CO₂ inside the leaf. The second limitation can be studied by determining the quantum requirement of photosynthesis. The third limitation is most easily detected as a loss of O₂ sensitivity of photosynthesis. Measurement of fluorescence from intact leaves can give additional information about the various limitations. These methods are all non-destructive and so can be observed repeatedly as the environment of a leaf is changed. In addition, leaves can be quick-frozen and metabolite concentrations then measured to give more information about the limitations to intact leaf photosynthesis rates. In this review the physics and biochemistry of photosynthesis in intact C₃ leaves, and the interface between physiology and photosynthesis—triose phosphate utilization—are discussed.     

A new Madia of sect. Anisocarpus (Compositae: Heliantheae) from Trinity County,California

A new annual species ofMadia sect.Anisocarpus,Madia doris-nilesiae, from the serpentine soils of western Trinity County, California is described, illustrated, and compared to the other annual members of the section. On the basis of floral and fruit morphologies the annual members of the section can be divided into two geographical units.Madia dorisnilesiae is unique in that it has a combination of these characters.     

Absolute configuration of the 5,6-oxide formed from 7,12-dimethylbenz[a]anthracene by cytochrome P450c

The absolute configurations of the enantiomeric 5,6-arene oxides of 7,12-dimethylbenz[a]anthracene (DMBA) were recently assigned such that the late eluting enantiomer from a chiral HPLC column has 5R,6S absolute configuration. [Mushtaq et al. (1984) BBRC 125, 539]. The authors further concluded that the 5R,6S-enantiomer predominates on metabolism of DMBA by cytochrome P450c in liver microsomes from 3-methylcholanthrene-treated rats. Their chemical assignment of absolute configuration is incorrect. Thus, metabolism of DMBA by these microsomes as well as by homogeneous cytochrome P450c produces 5,6-oxide highly enriched (95%) in the 5S,6R-enantiomer in accord with theoretical predictions.     

Holozygosity for sex-linked genes in males of the termiteIncisitermes schwarzi

The termite Incisitermes schwarzi has multiple sex chromosomes that have arisen by repeated translocations between autosomes and previously existing sex chromosomes. Two sex-linked allozyme loci--Acp-1 and Est-3--are holozygous, not hemizygous, in males (the heterogametic sex). Both loci show less than 1% crossing-over between X and Y chromosomes, and alleles of both are in marked disequilibrium with respect to X vs Y linkage. The two loci assort independently in female meiosis, indicating that they lie on different sex chromosomes. But they are tightly linked in male meiosis because of nonrandom assortment of the multiple X and Y chromosomes in males of this species. The findings of holozygosity and strong linkage disequilibrium suggest that differential selection in the two sexes at or near these loci may be responsible for the establishment of the translocations in this species. The existence of active Y-linked alleles also suggests that the translocations may have occurred recently.     

Evidence for a role of taurine in the in vitro oxidative toxicity of neutrophils toward erythrocytes

Production of hydrogen peroxide and secretion of myeloperoxidase by stimulated neutrophils resulted in myeloperoxidase-catalyzed oxidation of chloride to hypochlorous acid (HOCl), the reaction of HOCl with taurine to yield taurine monochloramine (TauNHCl), and accumulation of TauNHCl in the extracellular medium. When erythrocytes were present, the yield of TauNHCl was lower as the result of uptake of TauNHCl into erythrocytes. The zwitterion taurine was not taken up, but the anion TauNHCl and other anionic oxidants including taurine dichloramine (TauNCl2) and L-alanine chloramines were transported into erythrocytes by the anion-transport system. Oxidation of intracellular components such as glutathione (GSH) by taurine chloramines resulted in reduction of the chloramines and trapping of taurine within erythrocytes. At high oxidant:erythrocyte ratios, TauNHCl also oxidized hemoglobin (Hb) and depleted ATP, but caused little lysis. TauNCl2 was much more effective as a lytic agent. At low oxidant:erythrocyte ratios, the chloramines caused net loss of GSH when no glucose was provided, but Hb was not oxidized and GSH content returned to normal when glucose was added. Therefore, anionic chloramines may mediate oxidative toxicity when the neutrophil:erythrocyte ratio is high. Under more physiologic conditions, chlorination of taurine by neutrophils and the uptake and reduction of TauNHCl by erythrocytes prevents accumulation of oxidants and may protect blood cells, plasma components, and tissues against oxidative toxicity.