Chlorophyll a forms in Phaeodactylum tricornutum: Comparison with other diatoms and brown algae

The long-wave chlorophyll a forms in Phaeodactylum tricornutum (688 and 703 nm) change into a short-wave form, 670 nm, as a result of incubation with 55% glycerol, freeze-thawing, short ultraviolet irradiation and, probably, chloroplast preparation. This short-wave form is non-fluorescent. Fluorescence polarisation measurements indicate that the long-wave chlorophyll a molecules are oriented parallel to each other. Although “labile” long-wave chlorophyll a receives energy from Photosystem II pigments at room temperatures and follows the induction phenomena of fluorescence, it is indicated by afterglow experiments that it probably does not participate in Photosystem II.Long-wave chlorophyll forms in Fucus are stable and probably are related to Photosystem I.     

The bivalve boring Cuenulites amygdaloides nov. isp. in siliceous sponges from the Upper Cretaceous of Germany

Lower Campanian siliceous sponges from epicontinental deposits of the Subhercynian Cretaceous Basin in Germany contain amygdaloidal depressions which are distinguished as a new ichnospecies of the ichnogenus Cuenulites. These bioerosion traces are interpreted as borings of semi-endolithic bivalves, produced without significant rotation movement, probably mostly by chemical action. As there are no signs of tissue reaction in the bored sponges, the structure is considered to be produced post mortem to the sponge, probably in a foreshore-shoreface setting, with redeposition offshore.     

Les Bryozoaires de la formation d'âge paléocène (Danien probable)du Mont Aimé (Marne,Bassin parisien)

The Mont Aimé Formation, of doubtful age, likely paleocene and probably danian, yielded an association of 7 bryozoan species. Two of them are new: Plagioecia bibensis and Beisselina bigeyae. The stratigraphic conclusions are reduced because the other occuring species, among which are of great importance Planicellaria sp. aff. oculata d'Orbigny and Nellia sp. aff. stricta Labracherie, are probably new. The Bryozoans, which lived in an environment with strong terrigenous discharges, resisted to the mud invasion by means of the high number of their avicularia or respectively of the flexibility of their jointed zoaria or of their substratum.     

Segmental differences in the protein content of Drosophila imaginal discs

The protein content of various Drosophila imaginal discs was analysed by two-dimensional electrophoresis followed by silver-staining. Three proteins, identified as tropomyosins α and β and actin I, are more abundant in the metathoracic discs (haltere and third leg) than in the mesothoracic discs (wing and second leg). In the case of the wing disc, these proteins are probably contributed by the adepithelial (muscle precursor) cells, as indicated by their non-uniform localisation within the disc. Mutations in the bithorax complex have no effect on the difference between second and third leg discs. We conclude that there is a segmental difference in the protein content of homologous discs, that this difference is probably localized in the adepithelial cells, and that it is not under the direct control of known alleles of the bithorax complex.     

Sesquiterpenoids in two different kinds of agarwood

Sesquiterpenoids of an agarwood originating from Aquilaria agallocha and of the other kind of agarwood (Aquilaria sp.; probably Aquilaria malaccensis) were investigated by a combination of GLC and GC/MS. The differences in sesquiterpene composition between the two kinds of agarwood are discussed.     

Catabolic metabolism in Trypanosoma cruzi

Culture, blood and intracellular forms of Trypanosoma cruzi have a high rate of endogenous oxygen uptake and probably utilize amino acids and carbohydrates as their exogenous energy sources. It is likely that triglyceride is the main energy reserve. Oxidation of carbohydrate by all forms is probably via a glycolytic sequence and a complete tricarboxylic acid cycle. These data suggest that the substrates utilized and catabolic pathways present in mammalian forms of T. cruzi are similar to those of culture forms of the organism and are quite distinct from those of the bloodstream forms of African trypanosomes.     

The metabolism of 7- and 12-methylbenz[a]-anthracene and their derivatives

1. 7- and 12-Methylbenz[a]anthracene were converted by rat-liver homogenates into the corresponding hydroxymethyl derivatives, products that are probably the 8,9-dihydro-8,9-dihydroxy and the 5,6-dihydro-5,6-dihydroxy derivatives, and a number of phenolic products. 2. Both hydrocarbons were converted into glutathione conjugates; that from 7-methylbenz[a]anthracene was also formed, together with 5,6-dihydro-5,6-dihydroxy- and 5-hydroxy-benz[a]anthracene, from 5,6-epoxy-5,6-dihydro-7-methylbenz[a]anthracene. 3. 7- and 12-Hydroxymethyl-benz[a]anthracene were converted into products that are probably 8,9-dihydro-8,9-dihydroxy derivatives, and into phenols. 4. The preparation of a number of derivatives of the hydrocarbons is described. 5. The oxidation of the hydrocarbons with lead tetra-acetate was investigated.     

Contributions to the lichen flora of the Lakshadweep (Laccadive) Islands,India

Abstract:The first lichen records from the Lakshadweep (Laccadive) Islands are presented.Lithothelium insulare (Pyrenulaceae) is described as new and nine other taxa are reported. The poor lichen flora, dominated by pantropical species, is probably a result of the lack of natural habitats in this area.     

Exclusion of Bacteriophages by T2 Ghosts

T2 ghosts do not exclude T4, T7, or lambda-induction in Escherichia coli which survive ghost infection. Latent periods are extended, probably by the temporary inhibition of protein synthesis.     

The morphology and relationships of the walking mud spiders of the genus Cryptothele (Araneae: Zodariidae)

We revise the relationships of the spider genus Cryptothele after reexamination of the morphology of the spinnerets, leg tarsal claws and maxillae with scanning electron microscopy. Cryptothele species have a particular conformation of the spinning field of the anterior lateral spigots that is typical of zodariids and close relatives: the field of major ampullate gland spigots, together with their strain sensilla, are invaginated within the field of piriform gland spigots. The implantation of the teeth on the inner side of the leg tarsal claws is also consistent with its placement among zodariids. We added Cryptothele to a morphological dataset of zodariid genera, together with the outgroups Homalonychus (Homalonychidae) and Penestomus (Penestomidae). The phylogenetic analysis concludes that the genus Cryptothele is a member of the subfamily Cydrelinae, which by priority is here considered a junior synonym of Cryptothelinae. Cryptothele specimens cover most of their body with soil particles which become consolidated as mud, and the debris is probably held in place by curved setae covered by long barbs. The spinnerets, which can be retracted and hidden, as well as the booklungs, are surrounded by a crown of thick setae that are densely covered by short barbs, protecting those areas against soil particles. Cryptothele are probably specialized to prey on termites, and their phylogenetic placement indicates that this diet specificity evolved two times independently in zodariids.     

Anatomy of the prosauropod dinosaurBlikanasaurus cromptoni (Upper Triassic, South Africa), with notes on the other tetrapods from the lower Elliot Formation

The holotype of the prosauropod dinosaurBlikanasaurus cromptoni Galton & van Heerden 1985, a partial hindlimb, is described from the lower Elliot Formation (Red Beds; Carnian, Upper Triassic) of the Eastern Cape, South Africa.Blikanosaurus, along with the sympatricEuskelosaurus andMelanorosaurus, probably represent the oldest record of the Prosauropoda (certainly so for articulated remains). The prosauropod family Blikanasauridae is characterized by a hind-limb that is extremely stocky, especially the metatarsus.Blikanasaurus was an early heavily-built, quadrupedal saurischian, but it was probably not the ancestor for the Sauropoda. The other tetrapods of the lower Elliot Formation are reviewed with particular emphasis on the carnivorous dinosaurAliwalia rex.     

Evidence for random endonucleolytic cleavages between messages in decay of Escherichia coli trp mRNA

The mechanism of decay of polycistronic trp messenger RNA in Escherichia coli was studied by size analyses of decaying populations. By measuring the sizes of only those molecules that contained the most proximal (E mRNA) of the five messages it was shown directly that cleavages occur, probably at intercistronic junctions, and each one does so independently of cleavages or decay at any other sites, i.e. occurs with random kinetics. The polycistronic fragments of less than full-length size did not arise from premature terminations within the operon. These results agree with earlier conclusions for the lac and gal operons and suggest that the basic mechanisms of decay of polycistronic mRNAs are probably the same with internal cleavages occurring only at the intercistronic junctions.     

The functional morphology of the alimentary tract of barnacles (Cirripedia: Thoracica)

The alimentary tract of barnacles is made up of cuticle-lined foregut and hindgut with an intervening U-shaped midgut associated anteriorly with a pair of pancreatic glands and perhaps midgut caeca. Epithelial salivary glands secrete acid mucopolysaccharide, glycoprotein or both. Cells of all the midgut regions are capable of absorption which is carried out mainly by the anterior midgut and caeca. Midgut cells of Balanus balanoides (L.) show a seasonal variation in the distribution of intracellular lipid droplets. Midgut cells rest on an elastic basal lamina and secrete a peritrophic membrane which contains mucopolysaccharide and protein. Cells of the stratum perintestinale connect with the midgut epithelial cells via cell processes which probably translocate absorbed materials. Glycoprotein globules and lipid droplets accumulate in the body parenchyma of B. balanoides and are transported to the ovaries to form yolk (glycolipovitellin). The pancreatic gland cells of all barnacles are active secretory cells secreting proteinaceous material (probably digestive enzymes).     

The XmnI restriction-modification system: Cloning,expression, sequence organization and similarity between the R and M genes

The xmnIRM genes from Xanthomonas manihotis 7AS1 have been cloned and expressed in Escherichia coli. The nucleotide (nt) sequences of both genes were determined. The XmnI methyltransferase (MTase)-encoding gene is 1861 by in length and codes for 620 amino acids (aa) (68660 Da). The restriction endonuclease (ENase)-encoding gene is 959 by long and therefore codes for a 319-aa protein (35275 Da). The two genes are aligned tail to tail and they overlap at their respective stop codons. About 4 × 10⁴ units/g wet cell paste of R·XmnI was obtained following IPTG induction in a suitable E. coli host. The xmnIR gene is expressed from the T7 promoter. M·XmnI probably modifies the first A in the sequence, GAA(N)₄TTC. The xmnIR and M genes contain regions of conserved similarity and probably evolved from a common ancestor. M·XmnI is loosely related to M·EcoRI. The XmnI R-M system and the type-I R-M systems probably derived from a common ancestor.     

Distribution of Lambornella clarki (Ciliophora: Tetrahymenidae) and other mosquito parasites in California treeholes

Lambornella clarki (Ciliophora: Tetrahymenidae) was one of three common parasites infecting larvae of Aedes sierrensis (Diptera: Culicidae) in California treeholes sampled between 1983 and 1985. Lambornella occurred in 37 of 142 treeholes and was absent from holes with extremes of pH and high electrical conductivity. Ciliates were more common in treeholes in northern California, and L. clarki from all holes was pathogenic to Ae. sierrensis. Natural infection rates averaged 16.1% but reached 100% in some holes suggesting that epizootics may occur in natural host populations. Sequential sampling of treeholes indicated that free-swimming trophozoites appeared shortly after treeholes flooded, but their numbers declined in subsequent samples. Predation by Ae. sierrensis larvae and successful attack and entry of hosts probably accounted for this decline. Trophozoites were common in treehole water late in the season as adult mosquitoes were emerging, and these were probably released from moribund and dead infected hosts. The parasite persisted in dry treeholes between wet seasons in 90% of the cases indicating a highly efficient desiccation resistant cyst. Octomyomermis troglodytis (Nematoda: Mermithidae) and Ascogregarina clarki (Sporozoa: Eugregarinida) were found in 17 and 46 treeholes, respectively. The cooccurrence of these parasites and L. clarki within treeholes did not deviate from random, indicating that parasites are not segregated among larval habitats. All combinations of parasites were found within individual hosts suggesting that competitive forces in this parasite guild are probably weak.     

Design, Characterization, and In Vitro Evaluation of Antifungal Polymeric Films

The objective of the present paper was the development and the full characterization of antifungal films. Econazole nitrate (ECN) was loaded in a polymeric matrix formed by chitosan (CH) and carbopol 971NF (CB). Polyethylene glycol 400 and sorbitol were used as plasticizing agents. The mechanical properties of films were poorer when the drug was loaded, probably because crystals of ENC produces network outages and therefore reduces the polymeric interactions between the polymers. Polymers–ECN and CH–CB interactions were analyzed by Fourier-transform infrared spectroscopy (FTIR), thermal gravimetry analysis, and differential thermal analysis (DTA-TGA). ECN did not show structure alterations when loaded into the films. In scanning electron microphotographs and atomic force microscopy analysis, films prepared with CB showed an evident wrinkle pattern probably due to the strong interactions between the polymers, which were observed by FTIR and DTA-TGA. The in vitro activity of the formulations against Candida krusei and Candida parapsilosis was twice as greater as the commercial cream, probably as a result of the antifungal combination of the drug with the CH activity. All these results suggest that these polymeric films containing ECN are potential candidates in view of alternatives dosages forms for the treatment of the yeast assayed.     

‘Twisted plywood’ structure and mineralization in the scales of a primitive living fish Amia calva

The basal plate of the scales of Amia calva is composed of regular double twisted plywood, as in Latimeria and Dipnoan scales. However, the progressive rotation of the fibrils direction is left-handed in Amia and right-handed in the ‘Sarcopterygians’. So, the similarity between these peculiar plywoods is probably the result of convergence. The basal plate of Amia scales is incompletely mineralized. There are numerous calcified ovoid corpuscles which look very like the Mandl's corpuscles of Teleost scales. The mineralization probably progresses essentially by the fusion of these corpuscles, as in Teleost scales, and would be inotropic rather than spheritic.     

Rudabànya: Taphonomic analysis of a fossil hominid site from Hungary

The late Miocene deposits at Rudabànya, Hungary, were laid down in a shallow valley sloping westwards from a range of hills and opening out into the Pannonian Lake. Rise and fall of lake level gave rise to varying conditions, from dry land with soil formation to swamp and lake. The stratigraphic and palaeontological succession has been investigated at one of the sites, Rudabànya 2, where two cycles of deposition and erosion are represented, with soil formation, swamp conditions with lignite formation, and periods of extended high lake level succeeding each other. Both mammal and plant fossils are present at several levels. Taphonomic modifications in the Rudabànya 2 vertebrate faunas include losses of skeletal elements through carnivore selection, fluvial sorting at some levels, and post-depositional destruction by leaching and/or acid soils. The lowest level, the lower lignite, has few fossils. The fossil mammals from the level above, the grey marl, are the least modified but they are mixed with abraded, probably allochthonous, bone fragments and more complete specimens resulting from near-lake deaths. Modifications of bones by carnivores are indicated, but the specimens were too broken post-depositionally for the impact of the carnivores to be assessed. Carnivore action is also indicated for the fauna of the black clay which formed on the surface of the grey marl. The fauna consists of relatively abundant small mammals and the primates Anapithecus hernyaki and Dryopithecus hungaricus, with the latter much less common. The predator accumulating the smaller species was probably a viverrid. The red marl fauna is a transported assemblage from higher up the valley with the fossils extremely fragmentary and abraded and few identifiable specimens, almost all of which are teeth. The black mud fauna is also probably a transported assemblage, lower energy than the red marl environment, and the bones are much modified subsequently by acid corrosion similar to that seen today in bone preserved in peat bogs. Dryopithecus is a major constituent of the fauna, with Anapithecus less common. D. hungaricus is thus associated more strongly with swamp forest and shallow riverine conditions with low energy movement of water, and A. hernyaki is associated with lake shore (probably forest) conditions, accumulating in lake sediments and lake-flat sediments. The palaeoecology of the area as a whole, based on the associated flora and fauna, is a combination of swamp forest, lake shore forest and open mud flats.     

Cloning and sequence analysis of the putative rifamycin polyketide synthase gene cluster from Amycolatopsis mediterranei

The 54-kbp Type I polyketide synthase gene cluster, most probably involved in rifamycin biosynthesis by Amycolatopsis mediterranei, was cloned in E. coli and completely sequenced. The DNA encodes five closely packed, very large open reading frames reading in one direction. As expected from the chemical structure of rifamycins, ten polyketide synthase modules and a CoA ligase domain were identified in the five open reading frames which contain one to three polyketide synthase modules each. The order of the functional domains on the DNA probably reflects the order in which they are used because each of the modules contains the predicted acetate or propionate transferase, dehydratase, and β-ketoacyl-ACP reductase functions, required for the respective step in rifamycin biosynthesis.