Aulacotheca collicola n.sp. (medullosaceae) from the early Pennsylvanian of the Illinois basin

Compressed synangia referable to the medullosan pollen organ genus Aulacotheca Halle have been discovered in Early Pennsylvanian sediments from Rock Island County, Illinois, U.S.A. Specimens were recovered from localized shales containing floral elements suggesting an upland environment. Based on synangial size, morphology, sporangial number, and prepollen type, two distinct forms, A. collicola n.sp. and Aulacotheca sp., are recognized. Synangia of A. collicola are 11–17 × 2.5 – 4.0 mm and have four to six sporangia. Free sporangial tips are acutely pointed and dehiscence is through a longitudinal slit to the inside of the synangium. Prepollen averages 181 × 129 μm and has a monolete suture with median deflection. Sexine on proximal and distal surfaces shows narrow, closely spaced, anastomosing inpockets; distal and lateral walls are separated by a deep, encircling fold. Synangia of Aulacotheca sp. are 21–33 × 3.8 – 5.5 mm and have 4–6 sporangia. Distally, free sporangial tips have a narrow extension, giving a mucronate appearance. Features of these species suggest that greater morphological diversity in synangial and pollen structure occurs in Aulacotheca and the medullosan pteridosperms than previously recognized.     

An Early Permian plant assemblage from the Taiyuan Formation of northern China with compression/impression and permineralized preservation

A small but diverse fossil flora is described from the Early Permian Taiyuan Formation occurring at the Yangshuling mine in Pingquan district of Hebei Province, northern China. Fossils occur as compression/impressions within mudrocks and fine-grained sandstones and also as carbonate permineralizations within volcaniclastic tuffs. All are fragmentary and contain lycopsids, sphenopsids, ferns and seed plants, and include several new species. In the compression assemblage sphenopsid and pteridosperm foliage accounts for the majority of the fossils recognised with only a few other kinds of plant organs present. In contrast, the permineralized assemblage is dominated by cordaitaleans with a composition similar to that occurring in coal-ball assemblages elsewhere in the Taiyuan Formation. From the taxonomic synthesis presented it is apparent that the Yangshuling permineralized assemblage contains many of the plant taxa diagnostic of the northern realm of the Early Permian Cathaysian flora, and preserves a representative sample of the wetland coal-swamp vegetation of this time. The permineralized assemblage at Yangshuling represents the first example of anatomically preserved plants from volcaniclastic lithologies from the Palaeozoic of China, raising the possibility of similarly preserved plant-fossil assemblages elsewhere in the Cathaysian realm.     

A permineralized species of mangrove fern Acrostichum L. from Deccan Intertrappean beds of India

Acrostichum intertrappeum sp. nov., a permineralized aerial stem with helically arranged petioles and roots in organic connection, is described from the Deccan Intertrappean beds of Nawargaon, District Wardha, Maharashtra, India and forms the first and the oldest record of its kind. The stem is covered with a thick ramentum of large multicellular scales and is characterized by a three angled dictyostele enclosing a few medullary bundles. The petioles are helically arranged and the vascular morphology is distinct with abaxial horseshoe-shaped ring, adaxial linear row and central dorso-ventrally elongated ring. The roots have hexarch steles and aerenchymatous cortex with large air cavities in rings. Occurrence of Acrostichum along with coastal palms, mangroves and marsh plants described earlier from this region and nearby locations suggests the north-western shore of the Deccan was linked to the equatorial ocean (South Western Tethys Sea) probably through the Narmada Valley during the deposition of Intertrappean sediments. Morphological features and anatomical characters of the fossil reveal that Acrostichum grew in marsh swamp environment or on mud flats of back water areas of the coastal environment prevailing a tropical humid climate when the Deccan region was almost at an equatorial position during the Late Cretaceous period. This new record further adds to a growing body of data on the diversification of polypodiaceous ferns that point to a much earlier crown group radiation of the group than previously thought.     

Preliminary report onPresbytis francoisi leucocephalus

There is no long-term study on the white-headed leaf-eating monkey in Hua Shan, Guangxi Zhuang Autonomous Region, China. This subspecies probably numbers ≤400 animals (Wu, 1983; Jiang et al., 1991). Our preliminary study 15 km from the Vietnamese border documents group size and composition and habitat use based on 450 contact h. The study group may interact with the white-sideburned (white-cheeked or black) subspecies of Presbytis francoisi,and shares habitat with macaques. While the study site is contiguous with a provincial park and P. francoisiare under protective legislation, development of this area for tourism and occasional local hunting has consequences for conservation policy.     

Preliminary characterisation of inhibitors of DNA polymerase isolated from Xenopus laevis early embryos

Inhibitors of DNA polymerase have been detected in Xenopus laevis ovary and egg extracts. The characteristics of the inhibitors differ between the two extracts. In ovary preparations, the inhibitor is retained by dialysis tubing and is heat sensitive, whereas in egg extracts it is diffusable and heat stable. In both extracts, the activity co-elutes with DNA polymerase after ion exchange chromatography. Chromatography of ovary extracts renders the inhibitor diffusable and heat stable. Preliminary characterisation of inhibitory activity from eggs shows that the substance is sensitive to pronase digestion and has an approx. 300–500 molecular weight. Kinetic studies demonstrate that the inhibitor is uncompetitive with the DNA template and show mixed inhibitory kinetics with respect to the deoxynucleotides.     

Reconstruction in vitro of the flagellar polyhook from Salmonella

We have succeeded in the reconstitution in vitro of polyhook structures from monomeric hook proteins. Using immunoelectron microscopy, we found that monomeric hook proteins derived from a polyhook mutant of Salmonella were polymerized onto one of the two ends of each short fragment of polyhook from a mutant of Escherichia coli under physiological conditions. The polymerization occurred in one direction, the growing end corresponding to the distal end of an intact polyhook on a cell. The growth of polyhook fibers in vitro was very slow and the initial rate was saturated at 20 nm/h at monomer concentrations higher than 3 mg/ml. During growth. two or three fibers were sometimes associated with each other in a head-to-tail manner to produce longer ones. The experimental results are compared with those obtained for flagellin polymerization and several common features are found.     

Plankton algae from the Serpentine in Eaton Park,Chester

Collections of phytoplankton from an old natural freshwater pool in Cheshire have been made between 1932 and 1964, seasonal variations being especially noted. The flora was found to be rich with many genera represented, especially of the Chlorococcales. A number of rarely recorded forms are noted and some taxonomic uncertainties are discussed.     

Preliminary studies of monoterpenoid variability in Satureja douglasii

Monoterpenoid composition of samples from 10 populations of Satureja douglasii in a 250-ha area were analyzed in Spring 1974. Two distinct compositional types were found: Type A contained large amounts of limonene and carvone but very small quantites of piperitenone, piperitone, pulegone and isomenthone (3-oxy compounds), whereas Type B was essentially the reverse. This variation is attributed to a genotypic difference. The amounts of 3-oxy compounds varied greatly among the Type B populations. Increasing shade conditions were correlated with increased amounts of the more reduced compounds isomenthone and piperitone. Clonal lines were established from two Type B populations whose habitats represented extremes of sun and shade conditions. The two clonal lines, which had very different compositions in the field, produced similar oils under controlled conditions. Growth under different temperature regimes had little effect on composition. Developmental changes in composition implied the precursor-product relationships piperitenone→piperitone and pulegone→isomenthone. The data suggest that S douglasii monoterpenoid compositional patterns are significantly influenced by genetic and environmental factors (probably light intensity) as well as developmental processes.     

Phenolic compounds in Hypericum species from the Trigynobrathys section

Phenolic compounds of thirteen Hypericum species growing in South Brazil were investigated aiming to evaluate the usefulness of their distribution as a taxonomic character. The HPLC analysis of the methanolic fractions displayed similar chemical profile and significant contents variation among the investigated taxa, being chlorogenic acid the main metabolite quantified in most of the species (ranging from traces to 16.65 mg% of extract), followed by hyperoside (between 0.27 and 11.48 mg%), quercitrin (0.09 and 13.34 mg%), guaijaverin (0.14 and 2.91 mg%) and isoquercitrin (0.14 and 6.97 mg%), whereas rutin and the xanthone mangiferin were not detected.     

Tropane alkaloids from Anthocercis and Anthotroche

In addition to known tropane alkaloids, 3α-iso-butyryloxytropan-6β-ol and 3α-n-butyryloxytropane have been characterized as respective components of the aerial parts of two subspecies of Anthocercis albicans. Aponoratropine, not previously recorded as a natural product, has been detected in the leaves of Anthotroche myoporoides and A. walcottii; similarly aponorhyoscine is indicated as a component of the roots of a subspecies of Anthocercis genistoides.     

Preliminary studies on cryopreservation of snakehead (Channa striata) embryos

This paper reports the findings of the ongoing studies on cryopreservation of the snakehead, Channa striata embryos. The specific objective of this study was to collect data on the sensitivity of C. striata embryo hatching rate to low temperatures at two different developmental stages in the presence of four different cryoprotectants. Embryos at morula and heartbeat stages were selected and incubated in 1 M dimethyl sulfoxide (Me₂SO), 1 M ethylene glycol (EG), 1 M methanol (MeOH) and 0.1 M sucrose solutions at different temperatures for a period of time. Embryos were kept at 24 °C (control), 15 °C, 4 °C and −2 °C for 5 min, 1 h and 3 h. Following these treatments, the embryos were then transferred into a 24 °C water bath until hatch to evaluate the hatching rate. The results showed that there was a significant decrease of hatching rate in both developmental stages following exposure to 4 °C and −2 °C at 1 h and 3 h exposure in each treatment. Heartbeat stage was more tolerant against chilling at −2 °C for 3 h exposure in Me₂SO followed by MeOH, sucrose and EG. Further studies will be conducted to find the best method to preserve embryos for long term storage.     

Fossilized eggs from the Pennsylvanian of Illinois

Nine siderite concretions from the Middle Pennsylvanian, Francis Creek Shale (Carbondale Formation, Desmoinesian Series, West‐phalian C‐D), in the Mazon Creek area, Will‐Kankakee Counties, Illinois, U.S.A. preserve clusters of impressions of small eggs. Differential staining of the matrix suggests that the eggs were originally spawn within gelatinous strings containing 1 or 2 rows of eggs. Unfortunately, these egg impressions lack the diagnostic features needed to identify the zoological taxon (taxa) from which they originated.     

Terpenoids from the seed of Thujopsis dolabrata var. Dolabrata

Fourteen mono-, 13 sesqui-, 16 diterpenes, dodecanal, sitosterol and desoxypodophyllotoxin were identified in the seed of T. dolabrata var. dolabrata. Sabinene and α-pinene were found to be the main components of the volatile oil. From the diterpenoid fraction, two new abietane-type compounds (ar-abietatrien-12,16-oxide and 16-hydroxyferruginol) were isolated and their structures were elucidated. Significant differences were observed in the seed diterpenoids when these results were compared with those obtained earlier with T. dolabrata var. hondae.     

Structural features of the gum exudates from some Acacia species of the series Phyllodineae and Botryocephalae

Smith degradation of each of the polydisperse, gum polysaccharides from Acacia pycnantha, A. difformis, A. filicifolia, and A. podalyriaefolia, for which molecular-weight distributions have been measured by gel-permeation chromatography, gives, in good yield, a methanol-insoluble polysaccharide that shows a single peak on examination by this technique. The molecular weights of the Smith-degraded polysaccharides are close to the values expected if the respective gum polysaccharides, on losing periodate-vulnerable, peripheral sugar residues were to be split also at regular intervals between the otherwise (1→3)-linked d-galactose chains. The structures of these gums, which are similar in many respects, conform to the pattern shown recently to occur in the gum of A. baileyana.