Two new labdane diterpenoids and one new β-lactam from the aerial parts of Roylea cinerea

Two new labdane diterpenoids cinereanoid C (1), cinereanoid D (2), a new β-lactam, cinerealactam E (3) as well as six known flavonoid glycosides (4–9) were isolated from the aerial parts of Roylea cinerea (Lamiaceae). The structures of (1–9) were all determined by MS, IR and NMR spectroscopy. The structure of cinereanoid D (2) was further proven by single crystal X-ray diffraction. Six known flavonoid glycosides (4–9) were also isolated for the first time from this plant. 2, 5, 6 and 7 were found to significantly inhibit the ATP binding of a tumour growth-promoting heat shock protein, Hsp90.     

Fluorescent proteins in microbial biotechnology—new proteins and new applications

The recent advances over the past 5 years in the utilisation of fluorescent proteins in microbial biotechnology applications, including recombinant protein production, food processing, and environmental biotechnology, are reviewed. We highlight possible areas where fluorescent proteins currently used in other bioscience disciplines could be adapted for use in biotechnological applications and also outline novel uses for recently developed fluorescent proteins.     

Two new reactive targets of 2,5-hexanedione in vitro – beta-alanine and glycine

Summary. In this study, we found that two amino acids reacted with 2,5-hexanedione to form new reaction products in vitro, respectively. In the reaction of beta-alanine and 2,5-hexanedione, a reaction product was obtained and analyses of obtained results showed it was 3-(2,5-dimethyl-1H-pyrrol-1-yl)propanoic acid; in the reaction of glycine and 2,5-hexanedione, a reaction product was also obtained and analyses showed it was (2,5-dimethyl-1H-pyrrol-1-yl)acetic acid. Two reaction products were found to be oxidized easily; in addition, the latter was more easily to be oxidized than the former in the air. Our discoveries demonstrated that reactions between amino acids and 2,5-hexanedione could exist possibly in vitro. At present, it is clear that 2,5-hexanedione causes either axon atrophy or swelling, but the underlying molecular mechanism is still unclear. Since both beta-alanine and glycine are considered as neurotransmitter in the central nervous system, the reaction products remain to be identified in vivo.     

Two new“Meganthropus” mandibles from Java

There are now eleven known mandibular pieces from the Lower and Middle Pleistocene of Java, all but one being from the Sangiran site. All of these have been assigned toHomo erectus by most authorities, while others have suggested as many as four different hominoid taxa. Two of the mandibles, Sangiran 33 (Mandible H) and“Meganthropus”D (no Sangiran number yet assigned), are described here for the first time. The two new mandibles come from the Upper Pucangan Formation and date approximately 1.2–1.4 Myr. They are morphologically compatible with other“Meganthropus” mandibles described from Java. Despite attempts by numerous authorities to place all the Sangiran hominid mandibles in the species,H. erectus, the range of variation in metric and nonmetric features of the“Meganthropus” hominids is clearly beyond the know variation found inH. erectus. “Meganthropus” could represent a speciation from the well-knownH. erectus.     

Two new motile phototrophic consortia: “Chlorochromatium lunatum” and “Pelochromatium selenoides”

Two new phototrophic consortia, “Chlorochromatium lunatum” and “Pelochromatium selenoides”, were observed and collected in the hypolimnion of several dimictic lakes in Wisconsin and Michigan (USA). The two consortia had the same morphology but different pigment composition. The cells of the photosynthetic components of the consortia were half-moon-shaped. This morphology was used to differentiate them from the previously described motile phototrophic consortia “Chlorochromatium aggregatum” and “Pelochromatium roseum”. These phototrophic cells did not resemble any described unicellular green sulfur bacteria. The predominant pigments detected were bacteriochlorophyll d and chlorobactene for the green-colored “Clc. lunatum”, and bacteriochlorophyll e and isorenieratene for the brown-colored “Plc. selenoides”. Their pigment compositions and the presence of chlorosomes attached to the inner face of the cytoplasmic membrane in both kinds of photosynthetic cells confirmed this new half-moon-shaped morphotype as a green sulfur bacterium. Both consortia were found thriving in lakes with low concentrations of sulfide (< 60 μM), below the layers of “Clc. aggregatum” and “Plc. roseum”. The green consortia were observed in lakes where the oxic-anoxic interface was located at shallow depths (2–7 m), while the brown consortia were found at greater depths (8–16 m). The two newly described consortia were never detected together at the same depth in any lake. Received: 30 April 1997 / Accepted: 17 January 1998     

On the origin and evolution of new genes——a genomic and experimental perspective

The inherent interest on the origin of genetic novelties can be traced back to Darwin. But it was not until recently that we were allowed to investigate the fundamental process of origin of new genes by the studies on newly evolved young genes. Two indispensible steps are involved in this process:origin of new gene copies through various mutational mechanisms and evolution of novel functions, which further more leads to fixation of the new copies within populations. The theoretical framework for the former ...     

On the origin and evolution of new genes——a genomic and experimental perspective

The inherent interest on the origin of genetic novelties can be traced back to Darwin, But it was not until recently that we were allowed to investigate the fundamental process of origin of new genes by the studies on newly evolved young genes. Two indispensible steps are involved in this process: origin of new gene copies through various mutational mechanisms and evolution of novel functions, which fur-ther more leads to fixation of the new copies within populations. The theoretical framework for the former step formed in 1970s. Ohno proposed gene duplication as the most important mechanism producing new gene copies. He also believed that the most common fate for new gene copies is to become pseudogenes. This classical view was validated and was also challenged by the characterization of the first functional young gene jingwei in Drosophila. Recent genome-wide comparison on young genes of Drosophila has elucidated a compre-hensive picture addressing remarkable roles of various mechanisms besides gene duplication during origin of new genes. Case surveys revealed it is not rare that new genes would evolve novel structures and functions to contribute to the adaptive evolution of organisms.Here, we review recent advances in understanding how new genes originated and evolved on the basis of genome-wide results and ex-perimental efforts on cases, We would finally discuss the future directions of this fast-growing research field in the context of functional genomics era.     

Two new species ofPseudopetigurus (Trilobita) from the Arenig — Llanvirn of South China

Two new species ofPseudopetigurus are described from northern Hunan Province, China.P. deprati n. sp. is abundant in the upper Zitai Formation (upper Arenig) of Shuanghong, Baiyun, Shimen County, andP. expansus n. sp. occurs throughout the Jiuxi Formation (Arenig — lower Llanvirn) of Panjiazui, Taoyuan County. These formations represent outer shelf facies from the Jiangnan Transitional Belt of the South China Plate, close to the southeast margin of the Yangtze Platform. BothP. deprati andP. expansus show similarities to Upper Ordovician species ofPseudopetigurus recorded from South China. Other species ofPseudopetigurus are known almost entirely from cranidia, but pygidia and librigenae are also described for both new species, and the first known hypostome assigned to the genus is described forP. expansus. These two species are ecologically important members of offshore trilobite faunas during the Arenig — Llanvirn and define the outer shelfPseudopetigurus Association of South China. Despite being a deep-water genus,Pseudopetigurus is biogeographically restricted to the western margin of the Gondwanan craton and neighbouring regions of Baltica.      

Linkage in the mouse: The sex-linked genes and “rough”

Molecular Genetics and Genomics - The order of the totally sex-linked genes and the recombination frequencies in heterozygous females are — $$B_n - 11\% - Ta - 4\% - \left\{ {_{Mo}^{Br} }...     

Ethanol-hypersensitive and ethanol-dependent cdc − mutants in Schizosaccharomyces pombe

Ethanol-hypersensitive strains (ets mutants), unable to grow on media containing 6% ethanol, were isolated from a sample of mutagenized Schizosaccharomyces pombe wild-type cells. Genetic analysis of these ets strains demonstrated that the ets phenotype is associated with mutations in a large set of genes, including cell division cycle (cdc) genes, largely non-overlapping with the set represented by the temperature conditional method; accordingly, we isolated some ets non-ts cdc ^? mutants, which may identify novel essential genes required for regulation of the S. pombe cell cycle. Conversely, seven well characterized ts cdc ^? mutants were tested for their ethanol sensitivity; among them, cdc1–7 and cdc13–117 exhibited a tight ets phenotype. Ethanol sensitivity was also tested in strains bearing different alleles of the cdc2 gene, and we found that some of them were ets, but others were non-ets; thus, ethanol hypersensitivity is an allele-specific phenotype. Based on the single base changes found in each particular allele of the cdc2 gene, it is shown that a single amino acid substitution in the p34^cdc2 gene product can produce this ets phenotype, and that ethanol hypersensitivity is probably due to the influence of this alcohol on the secondary and/or tertiary structure of the target protein. Ethanol-dependent (etd) mutants were also identified as mutants that can only be propagated on ethanol-containing media. This novel type of conditional phenotype also covers many unrelated genes. One of these etd mutants, etd1-1, was further characterized because of the lethal cdc ^? phenotype of the mutant cells under restrictive conditions (absence of ethanol). The isolation of extragenic suppressors of etd1-1, and the complementation cloning of a DNA fragment encompassing the etd1 ⁺ wild-type gene (or an extragenic multicopy suppressor) demonstrate that current genetic techniques may be applied to mutants isolated by using ethanol as a selective agent.     

Obtaining and characterization of spherical particles—new biogenic platforms

The technique of obtaining spherical particles from rod-like plant virus, tobacco mosaic virus, in a preparative scale was developed. The conditions of tobacco mosaic virus isolation for obtaining spherical particles were selected. Spherical particles were examined by methods of electron microscopy, nanoparticle tracking analysis, and dynamic light scattering. Information about inner structure of spherical particles was obtained. High electron density of spherical particles was demonstrated. The analysis of ultrathin sections showed that spherical particles are homogenous within and do not contain any cavities.     

Stem Cell Proliferation and Quiescence—Two Sides of the Same Coin

The kinetics of label uptake and dilution in dividing stem cells, e.g., using Bromodeoxyuridine (BrdU) as a labeling substance, are a common way to assess the cellular turnover of all hematopoietic stem cells (HSCs) in vivo. The assumption that HSCs form a homogeneous population of cells which regularly undergo cell division has recently been challenged by new experimental results. For a consistent functional explanation of heterogeneity among HSCs, we propose a concept in which stem cells flexibly and reversibly adapt their cycling state according to systemic needs. Applying a mathematical model analysis, we demonstrate that different experimentally observed label dilution kinetics are consistently explained by the proposed model. The dynamically stabilized equilibrium between quiescent and activated cells leads to a biphasic label dilution kinetic in which an initial and pronounced decline of label retaining cells is attributed to faster turnover of activated cells, whereas a secondary, decelerated decline results from the slow turnover of quiescent cells. These results, which support our previous model prediction of a reversible activation/deactivation of HSCs, are also consistent with recent findings that use GFP-conjugated histones as a label instead of BrdU. Based on our findings we interpret HSC organization as an adaptive and regulated process in which the slow activation of quiescent cells and their possible return into quiescence after division are sufficient to explain the simultaneous occurrence of self-renewal and differentiation. Furthermore, we suggest an experimental strategy which is suited to demonstrate that the repopulation ability among the population of label retaining cells changes during the course of dilution.