Evolution,pollination, and systematics of the tribeNeottieae (Orchidaceae)

The various classifications of the orchid tribeNeottieae are reviewed and a new classification is proposed that divides the tribe into three subtribes,Neottiinae, Limodorinae, andCephalantherinae, based primarily on characters of the column (gynostemium). A cladistic analysis illustrates that these three subtribes are more closely related to one another than either is to any other group in subfam.Neottioideae, although there are very few apomorphic characters for the tribe. Pollination biology is also discussed showing links between breeding systems and distribution. There is also a possible role between column and labellum morphology and the emergence of a deceptive pollination syndrome from one of reward.     

Carbohydrate, protein and glycoprotein metabolism by the guinea-pig liver in chronic metribuzin poisoning

Male guinea-pigs weighing 400-600 g, 8 months old, were given metribuzin directly into the gastric lumen over a period of 30 days (20 animals) or 90 days (20 animals) 6 times a week. In the liver of the poisoned animals, the glycogen level and the AspAT and AlAT activities, while in the serum the total protein and the fractions albumin, alpha 1-globulin and gamma-globulin significantly decreased; serum glucose and the serum fractions alpha 2-globulin and beta-globulin, each showed an increase. The glycogen level in the liver, total protein, glucose as well as the alpha 1 and alpha 2 globulin fractions in the serum showed not appreciable difference between 30 and 90 days of intoxication. After 90 days of metribuzin treatment AspAT and AlAT dropped in the liver and rose in the serum, in comparison to the 30-day values. As to the parameters of glycoprotein metabolism, the intoxicated animals showed a significant decrease and increase in concentration of hexosamines and sialic acids in the liver and serum, respectively. Metribuzin intoxication also cause a significant decrease in activity of glucosamine phosphate isomerase and significant increase in activity of glycosidases in the liver. The results suggest that metribuzin disturbs the metabolism of carbohydrates, proteins and glycoproteins in the guinea-pig liver.     

Fructosamine in human and bovine semen.

We detected the presence of fructosamine in human and bovine semen. In seminal plasma of healthy normozoospermic men (N = 17) fructosamine was found in 53% of the cases (fru+). In fru+ semen samples the concentration of fructosamine was (mean +/- S.E.M., N = 9) 0.45 +/- 0.09 mmol/L and varied from 0.15 to 0.75 mmol/L. It was 3-12 times lower than in blood serum of healthy men. In semen of infertile men (N = 57) fructosamine was present only in 21% of the cases and its concentration was lower than in fertile men i.e. (mean +/- S.E.M., N = 12) 0.27 +/- 0.007 mmol/L. In bulls (N = 98) fructosamine was found in semen of 82% of animals. In fru+ semen samples the concentration of fructosamine was (mean +/- S.E.M., N = 80) 0.77 +/- 0.12 mmol/L and varied from 0.30 to 1.15 mmol/L. We did not find any correlation between the concentration of fructosamine on one hand, and that of fructose and glucose on the other hand, in either human or bull semen. The difference in the frequency of fructosamine appearance in semen of fertile and infertile men suggests that fructosamine may be in some way involved in the process of fertilisation.     

Specific template activity of ribonucleoprotein particles isolated from germinating Triticum aestivum embryo

A ribonucleoprotein (RNP) complex formed in wheat embryo at early germination stage was shown to be composed of 40-S RNP particle monomers and oligomers. RNA purified from this complex stimulated incorporation in vitro of various amino acids with efficiences dependent upon the frequencies of the corresponding codons calculated for this RNA from its base composition. Methionine was incorporated over the expected rate when the crude RNP complex, instead of the purified RNA, was used as the template. It is believed that the RNP complex represents a crude informosome fraction. The informosomes seem to contain a protein component that promotes the initiation of translation but does not involve the subsequent production of protein.     

Alignments grow, secondary structure prediction improves.

Using information from sequence alignments significantly improves protein secondary structure prediction. Typically, more divergent profiles yield better predictions. Recently, various groups have shown that accuracy can be improved significantly by using PSI-BLAST profiles to develop new prediction methods. Here, we focused on the influences of various alignment strategies on two 8-year-old PHD methods. The following results stood out. (i) PHD using pairwise alignments predicts about 72% of all residues correctly in one of the three states: helix, strand, and other. Using larger databases and PSI-BLAST raised accuracy to 75%. (ii) More than 60% of the improvement originated from the growth of current sequence databases; about 20% resulted from detailed changes in the alignment procedure (substitution matrix, thresholds, and gap penalties). Another 20% of the improvement resulted from carefully using iterated PSI-BLAST searches. (iii) It is of interest that we failed to improve prediction accuracy further when attempting to refine the alignment by dynamic programming (MaxHom and ClustalW). (iv) Improvement through family growth appears to saturate at some point. However, most families have not reached this saturation. Hence, we anticipate that prediction accuracy will continue to rise with database growth.