A nerve growth factor from the venom of Chinese cobra (Naja naja atra) and its effects on male reproductive system in rats

A nerve growth factor (NGF) was isolated from the venom of Chinese cobra (Naja naja ntr a) by ion exchange chromatography, gel filtration and fast protein liquid chromatography (FPLC). The N-terminal sequence of 22 amino acid residues was identical with other NGFs previously purified from the venom of the same genus. The NGF monomer molecular weight was estimated to be 13 500 by reducing SDS-PAGE and the isoelectric point was determined to be 7.2 by isoelectric focusing electrophoresis. NGF improved the epididymal sperm motility of male rats and increased the pregnancy rate and fetus number of mated female rats. The serum levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH) of male rats administrated NGF + gossypol was lower than that of male rats administrated gossypol. Histological sections of testes and epididymides showed that NGF reduced the destructive effects of gossypol on rat testes. (C) 1999 Elsevier Science Inc. All rights reserved.

Fruit anatomy,seed germination and seedling development in the Japanese seagrass phyllospadix

Phyllospadix iwatensis Makino and phyllospadix japonicus Makino have similar frunt morphology and anatomy.The rhomboid fruit of Japanese phyllospadix is dark brown in colour and is characterized by two arms bearing stiff inflected bristles which can act as an anchoring system. The fruit covering consists of a thin cuticular seed coat and pericarp remains mainly fibrous endocarp. In the groove region of the fruit.the cuticular seed coat and endocarp are replaced by nucellus cells with wall in growths and crushed pigment strands with lignified walls.these tissues appera to control the transfer of nutrients to developing seed.the seed is oval with a small embryo and a large hypocotyl. the embryo is straight and simple,with the plumule containing three leaf primordia and a pair of root primordia surrounded by a cotyledon.the hypocotyl has large vontral lobe containing central provascular tissue and two small dorsal lobes.the hypocotyl contains starch.lipid and protein.and acts as a nutrient store.the seed of P.iwatensis has a dormancy period of 2-6 weeks and germination eventually reaches-65%.but is not synchronized.during germination the leaves emerge first.and then after at least three young leaves have formed and abseised.the roots emerge,usually?6 months after the commencement of germination.Utilizaton of the nutrient reserves is initially from the perihpery of the hypocotyl and then progressively towards its centre.

Lack of latitudinal trends in wood anatomy of Dodonaea viscosa (Sapindaceae), a species with a worldwide distribution

Latitudinal or altitudinal variation in several anatomical characters of wood is common for woody dicotyledonous genera with a wide distribution, but whether such variation exists at the species level is disputed. Latitudinal and altitudinal trends in wood anatomy of Dodonaea viscosa were studied, using 102 samples collected between 41.2degrees S and 33.3degrees N latitude and 7-2750 in altitude. We studied variation in four quantitative features: vessel element length, fiber length, vessel frequency, and tangential vessel diameter. Ontogenetic trends were minimal with a slight decrease or increase in the innermost stem and were negligible among the studied specimens. Throughout the distributional range of the species, no latitudinal trends were detected in either the Northern or Southern Hemispheres, Altitudinal trends were also nonexistent, except for two features in specimens from China and Japan. Absence of latitudinal or altitudinal trends in this widely distributed species suggests that in some species the species-level variation in wood anatomy is not controlled by ecological gradients.