LECANORA COMPALLENS AND L. SINUOSA,TWO NEW OVERLOOKED CORTICOLOUS LICHEN SPECIES FROM WESTERN EUROPE

Lecanora compallens and L. sinuosa, two corticolous lichens, are described as species new to science on the basis of numerous collections. Lecanora compallens is a sorediate species, known only as sterile. It is probably common in Western Europe, but overlooked because it is very similar to L. expallens. Chemically, the new species is identical with L. strobilina, of which it may represent a sorediate counterpart. Lecanora sinuosa is a new species similar to L. chlarotera and so far only known from a limited area in the Netherlands and Germany, although it may be overlooked elsewhere. Lecanora sinuosa is very close to L. hybocarpa, with which it shares thepulicaris -type epihymenium inspersed with fine crystals but differs markedly by its thick thallus and thick and sinuous apothecium margin.     

Investigating the Roles of the C-Terminal Domain of Plasmodium falciparum GyrA

Malaria remains as one of the most deadly diseases in developing countries. The Plasmodium causative agents of human malaria such as Plasmodium falciparum possess an organelle, the apicoplast, which is the result of secondary endosymbiosis and retains its own circular DNA. A type II topoisomerase, DNA gyrase, is present in the apicoplast. In prokaryotes this enzyme is a proven, effective target for antibacterial agents, and its discovery in P. falciparum opens up the prospect of exploiting it as a drug target. Basic characterisation of P. falciparum gyrase is important because there are significant sequence differences between it and the prokaryotic enzyme. However, it has proved difficult to obtain soluble protein. Here we have predicted a new domain boundary in P. falciparum GyrA that corresponds to the C-terminal domain of prokaryotic GyrA and successfully purified it in a soluble form. Biochemical analyses revealed many similarities between the C-terminal domains of GyrA from E. coli and P. falciparum, suggesting that despite its considerably larger size, the malarial protein carries out a similar DNA wrapping function. Removal of a unique Asn-rich region in the P. falciparum protein did not result in a significant change, suggesting it is dispensable for DNA wrapping.     

Self-organization at the origin of life

The concept of an (M,R) system with organizational invariance allows one to understand how a system may be able to maintain itself indefinitely if it is coupled to an external source of energy and materials. However, although this constitutes an important step towards understanding the difference between a living and a non-living system, it is not clear that an (M,R) system with organizational invariance is sufficient to define a living system. To take a further step towards defining what it means to be alive it is necessary to add to a simple (M,R) system some property that represents its identity, and which can be maintained and modified in subsequent generations.     

A Review of the Fossil Record of the Genus Itea (Iteaceae, Saxifragales) with Comments on its Historical Biogeography

Itea is a genus of about 20 species of trees and shrubs that are today native to southeastern North America, eastern Asia, and eastern Africa. In this paper, I review the fossil record of Itea, which is based on four types of fossils: diporate, psilate pollen attributed to Itea or the dispersed pollen genus Iteapollis; carpofossils representing fruits and seeds attributed to Itea europaea; flowers preserved in amber and assigned to Adenanthemum iteoides; and leaf impressions attributed to Itea. The distributions of these fossils indicate that Itea was present in western North America from the early Eocene to Miocene, in eastern North America beginning no later than the early Miocene, and in western Eurasia from the late Eocene to Pliocene. Only one datapoint is known from eastern Asia; it is early Miocene in age. Based on the fossil record, it can be inferred that Itea crossed between continents over both the Bering Land Bridge and North American Land Bridge, and that it reached Africa from Europe via Anatolia. Thus, it is predicted that the sole extant North American species, I. virginica, may be most closely related to the sole extant African species, I. rhamnoides. The potential application of Itea fossils to calibrating phylogenetic trees generated from molecular sequence data is also discussed.     

A new hobo,Ac, Tam3 transposable element,hopper, from Bactrocera dorsalis is distantly related to hobo and Ac

A new transposable element from the hobo, Ac, Tam3 transposon family was isolated as a genomic clone from the Oriental fruit fly, Bactrocera dorsalis. It is approximately 3.1 kb in length with 19-bp inverted terminal repeat sequences having a single mismatch. Though sharing several amino acid sequence identities with other hAT elements, it is distantly related to both hobo and Ac. Among hAT elements thus far described in insects, it is apparently the most distantly related to hobo.     

UvrD and UvrD252 counteract RecQ, RecJ, and RecFOR in a rep mutant of Escherichia coli

Rep and UvrD are two related Escherichia coli helicases, and inactivating both is lethal. Based on the observation that the synthetic lethality of rep and uvrD inactivation is suppressed in the absence of the recombination presynaptic proteins RecF, RecO, or RecR, it was proposed that UvrD is essential in the rep mutant to counteract a deleterious RecFOR-dependent RecA binding. We show here that the synthetic lethality of rep and uvrD mutations is also suppressed by recQ and recJ inactivation but not by rarA inactivation. Furthermore, it is independent of the action of UvrD in nucleotide excision repair and mismatch repair. These observations support the idea that UvrD counteracts a deleterious RecA binding to forks blocked in the rep mutant. An ATPase-deficient mutant of UvrD [uvrD(R284A)] is dominant negative in a rep mutant, but only in the presence of all RecQJFOR proteins, suggesting that the UvrD(R284A) mutant protein is deleterious when it counteracts one of these proteins. In contrast, the uvrD252 mutant (G30D), which exhibits a strongly decreased ATPase activity, is viable in a rep mutant, where it allows replication fork reversal. We conclude that the residual ATPase activity of UvrD252 prevents a negative effect on the viability of the rep mutant and allows UvrD to counteract the action of RecQ, RecJ, and RecFOR at forks blocked in the rep mutant. Models for the action of UvrD at blocked forks are proposed.     

Radiation-stimulated DNA synthesis in cultured mammalian cells

A type of DNA synthesis in mammalian cells that is stimulated by ultraviolet light has been studied by means of radioautography and density gradient centrifugation. The characteristics of this synthesis are: (a) it is not semiconservative; (b) it is enhanced by the presence of 5-bromodeoxyuridine in the DNA molecule; (c) the degree of stimulation is dose dependent; (d) there is less variability in the rate of incorporation of H³-thymidine during this synthesis than during normal DNA synthesis; (e) it occurs in cells that are not in the normal DNA synthesis phase (G₁ and G₂ cells). This kind of synthesis has been found in cultured cell lines from five different species; however, in some strains, the presence of bromouracil in the DNA is required before it can be demonstrated by radioautography.     

Antihelimentic effect of Androctonus crassicauda scorpion venom against Trichuris arvicolae isolated from Psammomys obesus in Egypt

Trichuridae family has a genetic and morphological variability between species affecting rodents, but it is considerably hard to morphologically diagnose species within the genus of Trichuris and the individuals of these species are identified according to their host, as it is known that Trichuris spp. is strictly host-specific. However, some species lack host specificity. So, it is necessary to use molecular data in order to well identify the Trichuris spp. in Egyptian rodents. The host examined in the current research is Psammomys obesus and the molecularly identified species from its cecum is Trichuris arvicolae. In addition, Trichuris arvicolae was subjected to in vitro treatment with Androctonus crassicauda Crude Venom as a model of natural alternative treatment for gastrointestinal nematodes that increasingly develop anthelmintic drug resistance. The changes in Trichuris arvicolae were monitored using scanning electron microscopy, Androctonus crassicauda Crude Venom made a significant ultrastructural surface changes in Trichuris arvicolae, including marked cuticular sloughing, disintegrated bacillary glands, bursting of vulva and edema of anal region. This study was done for closer identification of Trichuris spp. infecting rodents in Egypt and evaluating the efficacy of Androctonus crassicauda Crude Venom in vitro.     

Deepsea herrings (Bathyclupeidae) of the northwestern Pacific ocean

Deepsea herrings of the northwestern Pacific (waters of Japan and Taiwan) are revised. Three species are recognized in this area, and two of them described as new: B. gracilis Fowler, 1938, B. japanotaiwana sp. n., and B. nikparini sp. n. B. japanotaiwana was previously mistakenly identified as the western Atlantic species B. argentea; actually it is especially similar to B. malayana, from which it differs in the bicolor oral cavity and in some meristic characters. B. nikparini is especially close to the Caribbean species B. schroederi, from which it differs in a greater number of developed gill rakers and smaller number of rays in the anal fin.     

Inviability of hybrids between D. melanogaster and D. simulans results from the absence of simulans X not the presence of simulans Y chromosome

Interspecific crosses between D. melanogaster and D. simulans or its sibling species result in unisexual inviability of the hybrids. Mostly, crosses of D. melanogaster females X D. simulans males produce hybrid females. On the other hand, only hybrid males are viable in the reciprocal crosses. A classical question is the cause of the unisexual hybrid inviability on the chromosomal level. Is it due to the absence of a D. simulans X chromosome or is it due to the presence of a D. simulans Y chromosome? A lack of adequate chromosomal rearrangements available in D. simulans has made it difficult to answer this question. However, it has been assumed that the lethality results from the absence of the D. simulans X rather than the presence of the D. simulans Y. Recently I synthesized the first D. simulans compound-XY chromosome that consists of almost the entire X and Y chromosomes. Males carrying the compound-XY and no free Y chromosome are fertile. By utilizing the compound-XY chromosome, the viability of hybrids with various constitutions of cytoplasm and sex chromosomes has been examined. The results consistently demonstrate that the absence of a D. simulans X chromosome in hybrid genome, and not the presence of the Y chromosome, is a determinant of the hybrid inviability.     

Three new species of oribatid mites of the genus Pergalumna (Acari: Oribatida: Galumnidae) from India

Three new oribatid mite species of the genus Pergalumna (Galumnidae) are described from growing mosses on rocks near a water stream in India. Pergalumna paraclericata sp. n. is very similar morphologically to Carinogalumna clericata (Berlese, 1914), however, it differs from the latter by the structure of lamellar lines and number of notogastral porose areas. Pergalumna minipora sp. n. is very similar morphologically to Pergalumna bifissurata Hammer, 1972, however, it differs from the latter by the body size and the presence of prodorsal ridges and a median pore. Pergalumna paracattienica sp. n. is very similar morphologically to Pergalumna cattienica Ermilov & Anichkin, 2011, however, it differs from the latter by the number of notogastral porose areas and the body integument on the ventral plate.     

On the recognition of anisacanthus junceus (Acanthaceae)

The Chihuahuan DesertAnisacanthus junceus (Torr.) Hemsl. is recognized as a distinct species and is compared withA. linearis to which it appears similar andA. wrightii to which it is possibly related.     

Identity of the downy mildew pathogens of basil, coleus, and sage with implications for quarantine measures

The downy mildew pathogen of basil (Ocimum spp.) has caused considerable damage throughout the past five years, and an end to the epidemics is not in sight. The downy mildew of coleus (Solenostemon spp.) is just emerging and here we report that it was very recently introduced into Germany. Although it has been recognised that these pathogens are a major threat, the identity of the pathogens is still unresolved, and so it is difficult to devise quarantine measures against them. Using morphological comparison and molecular phylogenetic reconstructions we confirmed in this study that the downy mildews of basil and coleus are unrelated to Peronospora lamii, which is a common pathogen of the weed Lamium purpureum. In addition, we conclude by the investigation of the type specimen of P. swingleii and downy mildew specimens on Salvia officinalis that the newly occurring pathogens are not identical to P. swingleii on Salvia reflexa. The taxonomy of the downy mildew pathogens of hosts from the Lamiaceae and, in particular, from the tribes Mentheae and Elsholtzieae, is discussed, and a new species is described to accommodate the downy mildew pathogen of basil and coleus, which is the first downy mildew pathogen known to be parasitic to hosts of the tribe Ocimeae.     

Molecular phylogeny and morphology reveal a new species of Amyloporia (Basidiomycota) from China

Amyloporia pinea sp. nov. is described and illustrated on the basis of collections from southern China. Morphology and phylogenetic analysis of rDNA ITS sequences support this new species. Morphologically, it is characterized by resupinate, annual basidiocarps, cream to yellowish buff pore surface when fresh, which becomes yellowish brown to clay-buff upon drying, a dimitic hyphal system with clamped generative hyphae and inamyloid skeletal hyphae, fusoid cystidioles, and cylindrical basidiospores; moreover, it causes a brown rot. Molecular phylogeny inferred from ITS sequence data suggested a close relationship between A. pinea and Amyloporia crassa sensu lato. Antrodia subxantha has amyloid skeletal hyphae, and grouped within the Amyloporia clade, hence, it is transferred to Amyloporia, and a new combination Amyloporia subxantha is proposed.     

A Product of the Tn5 Transposase Gene Inhibits Transposition

The bacterial transposon Tn5 possesses a regulatory mechanism that allows it to move with higher efficiency when it is first introduced into a cell than after it is established. Tn5 is a composite transposable element containing inverted repeats of two nearly identical elements, IS 50R, which encodes the transposase protein necessary for Tn5 movement, and IS50L which contains an ochre mutant allele of the transposase gene. Data presented here show that Tn5 transposition is inhibited about 50-fold in cells of Escherichia coli which already carry IS 50R in the multicopy plasmid pBR322. If the cells contain a plasmid carrying either IS50L instead of IS50R, or derivatives of IS 50R in which the transposase gene has been mutated, little if any inhibition of Tn5 transposition is found. Although inhibition had previously been hypothesized to require interaction between the products of IS50 L and IS50R, our results show that IS50R alone is sufficient to mediate inhibition and suggest that the inhibitor is a product of the transposase gene itself.     

The function of nickel on the urease activity of the lichen Evernia prunastri

The lichen Evernia prunastri synthesizes urease (EC 3.5.1.5) as a response to urea supplied in the medium. Nickel is required to produce the active protein. In addition, nickel behaves as an activator of the enzyme (K_a = 8.1 μM) at low concentrations whereas it is shown to be a competitive inhibitor of urease when it is supplied at concentrations higher than 40 μM (K_i = 50 μM).     

Identification of the uvrB gene product

We have constructed plasmids carrying various restriction fragments of the biouvrB region of the Escherichia coli chromosome. By analyzing the proteins synthesized in maxicells from the uvrB⁺ plasmid pDR1494, and its derivatives containing γδ sequences inserted in the uvrB gene, we have determined that the uvrB gene is about two kilobase-pairs in length, that it is transcribed clockwise on the standard E. coli genetic map, and that it codes for a single polypeptide of M_r = 84,000. The number of uvrB polypeptides in a normal cell is estimated to be about 140.We have also found that the uvrB gene is cut by EcoRI near its promoter.     

Cell-Wall Interactions and the Selective Bacteriostatic Activity of a Miniature Oligo-Acyl-Lysyl

The oligo-acyl-lysyl, C_12(ω7)K-β₁₂, is comprised of only three Lys residues. Despite its small size, it exhibits potent bacteriostatic activity against Gram-positive bacteria, but it is ∼10-fold less potent against Gram-negative bacteria. We followed the interactions of C_12(ω7)K-β₁₂ from its initial contact with the bacterial surface across the cell wall down to the cytoplasmic membrane. Binding to anionic lipids, as well as to negatively charged LPS and LTA, occurs with very high affinity. The C_12(ω7)K-β₁₂ does not cross the outer membrane of Gram-negative bacteria; rather, it achieves its action by depositing on the LPS layer, promoting surface adhesion and blocking passage of solutes. In Gram-positive bacteria, the thick peptidoglycan layer containing LTA allows passage of C_12(ω7)K-β₁₂ and promotes its accumulation in the small periplasm. From that location it is then driven to the membrane by strong electrostatic interactions. Despite its high potency against Gram-positive bacteria, this agent is not capable of efficiently breaking down the permeability barrier of the cytoplasmic membrane or of reaching an intracellular target, as suggested by the fact that it does not interact with DNA.     

Leucothoe eltoni sp. n., a new species of commensal leucothoid amphipod from coral reefs in Raja Ampat,Indonesia (Crustacea,Amphipoda)

A new species of leucothoid amphipod, Leucothoe eltoni sp. n., is described from coral reefs in Raja Ampat, Indonesia where it inhabits the branchial chambers of solitary tunicates. With an inflated first gnathopod superficially resembling the genus Paraleucothoe, this new species has a two-articulate maxilla 1 palp characteristic of the genus Leucothoe. While described from coral reef environments in tropical Indonesia and the Philippines, it is an established invasive species in the Hawaiian Islands. The most likely mode of introduction was a US Navy dry dock transported to Pearl Harbor in 1992 from Subic Bay, Philippines.