Alkaloid chemotaxonomy of the genus Sophora

Cytisine and matrine alkaloids detected in Sophora species have been used to classify the genus chemotaxonomically.     

Megagametogenesis in Halophila johnsonii, a threatened seagrass with no known seeds,and the seed-producing Halophila decipiens (Hydrocharitaceae)

Megagametogenesis, the development of a megaspore into an embryo sac, has been identified in the seagrass Halophila johnsonii, a threatened species with no known sexual reproduction or seeds. Megagametogenesis in H. johnsonii was compared with megagametophyte development in Halophila decipiens, a related species known to readily produce viable seeds. In both species, ovules were structurally similar, megaspore mother cells were seen in premeiotic ovules, and linear tetrads and megagametophytes with two to eight nuclei were present in postmeiotic ovules. However, H. decipiens postmeiotic ovules had a chalazal pouch that was absent in the postmeiotic ovules of H. johnsonii. Late-stage H. decipiens ovules also contained embryos, indicating that they had been fertilized, whereas all late-stage H. johnsonii ovules were degrading and showed no signs of fertilization. These observations suggest that meiosis does occur in H. johnsonii megasporocytes, leading to the formation of viable megagametophytes and egg cells that could be fertilized if pollination occurred. Thus, the lack of seed set is due to a lack of pollination rather than any loss of capacity to produce seeds in this species.     

Essential oil composition of Hypericum L. species from Southeastern Serbia and their chemotaxonomy

The essential oils of the aerial parts of nine species of Hypericum (Hypericum barbatum, Hypericum hirsutum, Hypericum linarioides, Hypericum maculatum, Hypericum olympicum, Hypericum perforatum, Hypericum richeri, Hypericum rumeliacum and Hypericum tetrapterum), collected from different locations in Southeast Serbia, were obtained by steam distillation and analyzed by GC and GC–MS. The essential oils investigated were characterized by a high content of non-terpene compounds and a low content of monoterpenes. The contents of non-terpenes, monoterpenes and sesquiterpenes in oils of the species H. barbatum, H. richeri and H. rumeliacum (section Drosocaprium) were similar and these oils were characterized by high contents of fatty acids. The oils of H. hirsutum and H. linarioides (section Taeniocarpium) contained a high percentage of n-nonane. There were similarities in contents of non-terpenes and sesquiterpenes in oils of species that belong to the section Hypericum (H. maculatum, H. perforatum and H. tetrapterum). The oil of H. olympicum differed from others by higher terpene content. A comparison was also carried out of the chemical composition of the essential oils from flower, leaf and stem of H. perforatum and it revealed that the highest concentration of non-terpene compounds was found in the flower and stem oil, while a high concentration of sesquiterpenes was characteristic for leaf oil. There were significant differences in the concentrations of the same compounds in the essential oils of H. maculatum, H. olympicum and H. perforatum, collected in different years from the same location which could be explained by seasonal differences. All data were statistically processed with principal component analysis and cluster analysis. The main conclusion from the above data is that genetic and environmental factors both play a role in determining the composition of essential oils of the Hypericum species studied.     

Northern range extension of the seagrasses Halophila johnsonii and Halophila decipiens along the east coast of Florida,USA

The northern geographic limit for Halophila johnsonii and Halophila decipiens has been reported as Sebastian Inlet, within the Indian River Lagoon, Florida. Surveys conducted in August 2007 determined the new northern limit to be 21.5 km north of the previously known limit. This new northern limit is a 10% range extension for H. johnsonii, a federally threatened species. We conclude that these range extensions are recent, based on (1) the small size of patches; (2) unusually good water clarity conditions due to a recent drought; (3) recent mild/warmer winters; and (4) a recent mechanism for transporting propagules, the numerous hurricanes of 2004. Although this recent range extension is considered ephemeral, similar range extensions may have occurred in the past and may occur again in the future under favorable conditions given the high capacity of these two species for dispersal to favorable sites. The northern limits of these species should not be viewed as static locations; rather, they must be considered dynamic features.     

The relationship between Trichocerca pusilla (Jennings), Aulacoseira spp. and water temperature in Loch Leven,Scotland, U.K.

Loch Leven is a shallow, eutrophic lake in the Scottish lowlands that is famous for its brown trout (Salmo trutta L.) fishery. Studies of planktonic rotifer populations began here in January 1977. Since then, samples have been collected and analysed at more or less weekly intervals. Additional information on the composition and abundance of phytoplankton and crustacean zooplankton species, and on a variety of physical and chemical determinants, has been recorded on each sampling occasion.Long-term datasets, such as that described above, are invaluable for identifying interactions between components of the plankton that only appear for short periods each year, as these interactions would probably be overlooked in data spanning a shorter period of time. This study uses the long-term data from Loch Leven to examine the food and temperature requirements of the summer rotifer species Trichocerca pusilla (Lauterborn). The results suggest that T. pusilla prefers water temperatures above 12 °C and that it feeds, primarily, on the filamentous diatom Aulacoseira spp. During the summer months, its abundance was closely related to the availability of this diatom. When filaments of Aulacoseira spp. were abundant, rotifer densities reached 1000–3000 ind. l^–1 and when they were scarce (e.g. 1980, 1997 and 1998) T. pusilla densities also remained low (i.e. less than 100 ind. l^–1). The reason for the success or failure of Aulacoseira during the summer months each year is unclear but, in general, its abundance was related to the availability of dissolved silica in the water.     

Localization and distribution of catecholaminergic structures in the nervous system of Phocanema decipiens (nematoda)

The nervous system of Phocanema decipiens was examined with both the formaldeyhyde-induced and the glyoxylic acid fluorescence histochemical techniques. Green catecholaminergic structures were observed in 4 cephalic papillary nerves, 2 fibres with varicosities in the nerve ring as well as the ventral nerve cord and a pair of lateral nerves.The papillary nerves, extending from the nerve ring to the lips region, have cell bodies which are located anterior or adjacent to the nerve ring. Cell bodies of the lateral nerves are found within the lateral cord tissue posterior to the nerve ring. Each of these neurons has 3 processes—one joins with the nerve ring, the other merges with the ventral nerve cord and the third ends abruptly within the lateral cord.     

The characterization of N-acetylglucosaminidases from the limpet Patella vulgata (L.)

The α- and β-N-acetylglucosaminidase activity of the limpet Patella vulgata (L.) is due to two enzymes. One of these enzymes hydrolyses both α- and β-N-acetylglucosaminidases and is referred to α,β-N-acetylglucosaminidase. The other is a β-N-acetylglucosaminidase (EC 3.2.1.30). Both enzymes have been isolated and characterized as glycoproteins containing 12% hexose, mainly galactose. The amino acid, neutral sugar and amino sugar content of the two enzymes is very similar, and the main difference lies in the presence of 9% sialic acid in β-N-acetylglucosaminidase. The molecular weight of α,β-N-acetylglucosaminidase is 217 000 and that of β-N-acetylglucosaminidase is 136 000. Evidence has been obtained for the presence of an additional sub-unit in the α,β-enzyme.     

Growth regulators from the seaweed Chondrus crispus L. (Lyn.)

The level of auxin-like compounds extracted from the seaweed Chondrus crispus L. (Lyn.) is reported. Their presence before and after alkaline hydrolysis is studied to confirm that the bound auxin-like substances are present in algae in greater concentration than the free form.     

Epizoan associations in a lower mississippian paleocommunity (borden group,Indiana, U.S.A.)

Epizoans were part of an epifaunal suspension‐feeding paleocommunity of the interchannel mudstone fades of the Borden delta (Edwardsville Formation, Mississippian, Indiana, USA). The paleocommunity was composed predominantly of bryozoans, crinoids, and brachiopods. A total of 26 epizoans and 42 potential hosts were present with Composita globosa, crinoids, and Cladochonus beecheri the principal hosts. Associations are classified as obligate, preferred, random, variable, and limited data. Stenoporid sp. B, Phosphannulus sp., and Platyceras spp. had obligate relationships with crinoids; Cornulitella sp. and Dendrina sp. had obligate relationships with Composita globosa; Ropalonaria sp. had an obligate relationship with Cladochonus beecheri; and Amplexizaphremis? sp. had an obligate relationship with fenestrate bryozoans. The following taxa had preferred associations to more than one host: Ascodictyon sp., Cheilotrypa sp., Corynotrypa sp. A, Corynotrypa sp. B, Fistulipora sp., Heteralosia keokuk, stenoporid sp. A, and fenestrates. Totypammina sp. displayed a nearly random pattern of settlement; and Cladochonus beecheri, Spirorbis sp., Thuramminoides sp., and crinoids have variable associations with hosts between the two localities studied.     

Orientated growth of Membranipora membranacea (L.) on the thallus of Saccorhiza polyschides (Lightf.) Batt.

Orientated growth is described in colonies of Membranipora membranacea (L.) growing on the large brown seaweed Saccorhiza polyschides (Lightf.) Batt. On average, 60% of the growth of the colonies was directed proximally along the long axis of the plant, irrespective of the region of the plant on which the colonies were growing or their proximity to its primary meristem. These results seem to rule out the possibility that orientated growth in Membranipora is a response to an age dependent polarity in the host plant, since the tissue ages in opposite directions in the lamina and stipe yet the growth of Membranipora is orientated in the same direction on both. The possibility that directional growth in this species may be a rheopositive response is discussed.     

Synchrony of oestrus and conception in red deer (Cervus elaphus L.)

Oestrus is synchronized in non-lactating wild red deer females (hinds) that associate together during the mating season (rut). Female relatives associate together and this association leads to synchronous oestrus within kin groups which is not due to kinship per se. Estimated conception dates show only slight synchrony between associated hinds, probably due to the failure of some hinds to conceive at the first oestrus. Hinds that were lactating during or immediately prior to the rut show no tendency to conceive synchronously. Possible advantages of synchronized oestrus and conceptions are discussed.