Analysis of the Bacillus subtilis recO gene: RecO forms part of the RecFLOR function

The deduced protein product of the Bacillus subtilis gene yqfI, which is 255 residues long, shares homology (25% identity) with the Escherichia coli RecO protein. A null allele of yqfI, when present in an otherwise Rec⁺ B. subtilis strain, causes cells to become highly sensitive to DNA-damaging agents, and plasmid transformation (intramolecular recombination) is reduced by 25-fold while chromosomal transformation (intermolecular recombination) is only moderately affected (2.5-fold reduction). Therefore, the yqfI gene was renamed recO and its null allele is referred to as recO1. The recO1 mutation was introduced into recombination-deficient strains representative of the epistatic groups α (recF, recR and recL strains), β (addA5 addB72), γ (recH342) and ? (recU40). The recO mutation did not affect the sensitivity of recF, recR or recL cells to DNA-damaging agents, increased the sensitivity of recU and addAB cells and abolished the DNA repair capacity of recH cells. The recO mutation did not affect intermolecular recombination in recF, recL, recH or recU cells, but reduced (by about 9-fold) the incidence of intermolecular recombination in addAB cells. The recO mutation did not affect intramolecular recombination in the addAB, recU, recF or recL cells, but reduced it by about 75-fold in recH cells. The defects caused by the recO1 mutation can be partially suppressed by a common suppressor of the recF, recL and recR phenotypes. We therefore assigned recO to epistatic group α and predict that the RecO protein acts at the same stage of recombination as the RecF, RecL and RecR proteins, in a RecFLOR complex.     

A study of the mechanism of the antiarrhythmic action of Allapinin

Allapinin (lappaconitine hydrobromide) is a drug used for the treatment of cardiac rhythm disturbances; its properties are characteristic of class IC antiarrhythmics. The mechanism of its electrophysiological action involves the blockade of Na⁺ channels with a subsequent decrease of depolarization rate leading to a slowing of impulse propagation and a decrease of excitability in the conductive system of the heart. Factors underlying the side effects of Allapinin (tachycardia, arterial hypertension, impaired coordination, etc.) are currently unknown, and therefore a study of the molecular mechanisms of its action seems relevant. The target genes of the drug were identified in rats with induced aconitine arrhythmia using the commercially available Rat Neuroscience Ion Channels & Transporters RT² Profiler? PCR Array kit (SA Biosciences). A comparison of expression levels of 84 genes in rats treated with Allapinin, after the induction of arrhythmia by aconitine (experiment) and in physiological saline-treated arrhythmic rats (control), revealed 18 mRNAs which were up- or downregulated twofold or more in the experiment relative to the control. Allapinin was shown to stimulate the expression of genes coding for various types of K⁺ channels (kcna6, kcnj1, kcnj4, kcnq2, and kcnq4), Ca²⁺ channel (cacna1g), and vesicular acetylcholine transporter (slc18a3). A decrease in mRNA levels was detected for genes coding for K⁺ channels (kcne1, kcns1), a Na⁺ channel (scn8a), and membrane transporter genes (atp4a, slc6a9). Our data shows that Allapinin administered to animals with aconitine arrhythmia modulates the expression of genes accounting for ion current conductances involved in the formation of various phases of action potential (I _Na , I _to , I _Ks , I _K1 , I _CaT ). The effect of the drug on the levels of mRNAs coding for acetylcholine and glycine transporters suggests the involvement of these neuromediators in the mechanisms underlying the antiarrhythmic effect of Allapinin.     

Phylogenetic overview of the Boletineae

The generic and sub-generic relationships in the Boletineae (Boletales) were studied using nuclear large subunit (nuc-lsu), translation elongation factor 1-alpha (tef1), and DNA directed RNA polymerase largest subunit (RPB1). The Boletineae, with the exclusion of Hydnomerulius pinastri, was strongly supported and the status of the families Boletaceae and Paxillaceae is discussed. Members of the genus Boletus are found throughout the phylogeny, with the majority not closely related to the type species, Boletus edulis. Many of the traditional, morphologically defined genera are not supported as monophyletic and additional sampling and taxonomic revisions are needed. The majority of the Boletineae are confirmed or putatively ectomycorrhizal (ECM), but two putatively mycoparasitic lineages (one lineage of Buchwaldoboletus lignicola and Chalciporus piperatus and the second Pseudoboletus parasiticus) are strongly supported.     

A New Interpretation of the Dynamic Changes of the Potassium Conductance in the Squid Giant Axon

The solutions, n(t), of the differential equation dn/dt = α (1 - n) n (4 - 6n + 4n² - n³) - βn² (4 - 6n + 4n² - n³) in which α and β are instantaneous functions of membrane potential, are shown to fit with good accuracy the time courses of the rise of potassium conductance during depolarizing steps in clamp potential, found experimentally by Hodgkin and Huxley and by Cole and Moore. The equation is derived by analysing the dynamic behaviour of a system consisting of a square array of interacting pores. The possible role of Ca⁺⁺ ions in this system is discussed.     

Genotypes of the vitamin D-binding protein gene in patients with chronic obstructive pulmonary disease and in the healthy population of the Republic Bashkortostan

Allele and genotype frequency distributions of the vitamin D-binding protein gene (DBP) were studied in patients with chronic obstructive pulmonary disease (COPD, N = 298) and healthy individuals (N = 237) from two ethnic groups (Tatars and Russians) resident in the Republic Bashkortostan. The DBP genotype frequency distribution significantly differed between Tatars and Russians (X ² = 8.854, df = 5, P = 0.04). The DBP allele frequency distribution was similar in healthy subjects of both ethnic groups, with allele frequency decreasing as GC*1S > GC*1F > GC*2. The most common DBP genotype was GC*1F/1S in Tatars (36.79%) and GC*1S/2 in Russians (34.62%). It was demonstrated that, in Tatars, the genotype GC*1F/1S is protective against COPD, its frequency being significantly lower in COPD patients than in healthy subjects (19.85% vs. 36.79%; X ² = 7.622, P = 0.0067, P _cor = 0.0335; OR = 0.42, 95%CI 0.42–0.95). On the other hand, the genotype GC*1F/2 was more common among COPD patients than among healthy individuals (19.08% vs. 8.49%; X ² = 4.52, P = 0.033, P _cor = 0.165; OR = 2.54, 95%CI 1.067–6.20). No differences in DBP genotype and allele frequency distributions was found between COPD patients and healthy individuals in the Russian population.     

Contributions to the mosquito fauna (Diptera, Culicidae) of Belgorod Province

The results of long-term studies of mosquitoes in Belgorod Province are reported. The material was collected at 54 sites situated in 15 districts of the province. Different biotopes were investigated during the spring-autumn period. Larvae and adult mosquitoes were used for identification. A total of 27 mosquito species were found in the region examined. The following species were recorded for the first time: Ae. (Och.) communis. Ae. (Och.) diantaeus. Ae. (Och.) pulchritarsis. Ae. (Och.) sticticus, and Cx. (Bar.) modestus; and also the form Cx. (Cux.) pipiens pipiens biotype molestus. The frequency of occurrence of each species in different biotopes and different localities is given. The most widespread and common species in Belgorod Province include Ae. (Och.) cantans (Mg.), Ae. (Och.) cataphylla Dyar, Ae. (Fin.) geniculatus (Ol.), Ae. (Adm.) vexans (Mg.), Cx. (Cux.) pipiens, and Cx. (Cux.) pipiens pipiens biotype molestus.     

Taxonomic survey of fossil isocrinids with a list of the species found in the USSR

The taxonomic scheme of the two families of the order Isocrinida (Isocrinidae and Pentacrinidae) is given. The first family is divided at five subfamilies: Balanocrininae, Isocrininae, Metacrininae, Diplocrininae and Isselicrininae. Six genera are included in subfamily Balanocrininae: Balanocrinus (four species found in USSR), Laevigatocrinus (USSR: 3 species), Margocrinus (USSR: 4 species), Percevalicrinus (USSR: 5 species), Singularocrinus nov. gen. (monotypic) and Terocrinus nov. gen. (USSR: 1 species). Five fossil genera are included in subfamily Isocrininae: Chariocrinus (USSR: 1 species), Chladocrinus (USSR: 4 species), Isocrinus (USSR: 6 species), Raymondicrinus nov. gen. (Oligocene of USA : 2 species) and Tyrolecrinus nov. gen. (6 triassic species). Fossil representatives of three genera, namely, Metacrinus (Miocene-Recent), Nielsenicrinus (USSR: 4 species) and Cainocrinus (USSR: 1 species) are noted in subfamily Metacrininae. Five genera are included in subfamily Isselicrininae: Austinocrinus (USSR: 5 species), Buchicrinus (USSR: 5 species), Doreckicrinus (USSR: 1 species?), Isselicrinus (USSR: 4 species) and Praeisselicrinus (USSR: 1 species). Two genera are included in family Pentacrinidae: Pentacrinus (USSR: 1 species) and Seirocrinus (USSR: 4 species). Besides, the localities of 24 isocrinid species, systematic position of which is unknown, are listed (from Triassic upon Cretaceous). Three erroneous attributions to Isocrinida in USSR are pointed out. In the conclusion an outline of the phylogeny of the Isocrinida is discussed. For a majority of the wide-spread species in USSR figures are given.     

Dioptrics of the facet lenses in the dorsal rim area of the cricket Gryllus bimaculatus

1. The optics of the corneal facet lenses from the dorsal rim area (DRA) and from the dorso-lateral areas (DA) of the compound eye of the cricket Gryllus bimaculatus were studied.
2. The DRA of the cricket eye contains quite normally shaped facet lenses. The diameter of the facet lens in the DA is 2-fold larger compared to that in the DRA. The radius of curvature of the front surface is distinctly less in the DA facet lenses, as the surface of the facet lenses in the DRA are virtually flat.
3. The averaged axial refractive index of the facet lenses of Gryllus bimaculatus, measured by interference microscopy, was 1.496 ± 0.008 (n = 42) in the DRA and 1.469 ± 0.004 (n = 39) in the DA. The geometrical thickness of the lenses was calculated to be 77 ± 3 μm (n = 42) in the DRA and 56 ± 1 μm (n = 39) in the DA.
4. Analysis of the diffraction pattern obtained with a point light source revealed distinct focusing properties of both the DRA and the DA facet lenses; striking Airy-like diffraction patterns were obtained in both cases.
5. Focal distances measured directly at the backfocal plane were 40 ± 8 μm (n = 84) in the DRA of all the animals studied, and 60–90 μm (n = 62) in DA depending on the animal. Analysis of the diffraction of the point light source yielded very similar focal distances: 40 ± 5 μm (n = 10) in DRA and 81 ± 8 μm (n = 11) in DA. In the DRA, focal distance of the facet lenses was smaller than the cone length, 58 ± 3 μm (n = 9) while in the DA the focal distance matched the effective cone length, 71 ± 5 μm (n = 16).

     

Changes in the Daily Rhythm of Lipid Metabolism in the Diabetic Retina

Disruption of circadian regulation was recently shown to cause diabetes and metabolic disease. We have previously demonstrated that retinal lipid metabolism contributed to the development of diabetic retinopathy. The goal of this study was to determine the effect of diabetes on circadian regulation of clock genes and lipid metabolism genes in the retina and retinal endothelial cells (REC). Diabetes had a pronounced inhibitory effect on the negative clock arm with lower amplitude of the period (per) 1 in the retina; lower amplitude and a phase shift of per2 in the liver; and a loss of cryptochrome (cry) 2 rhythmic pattern in suprachiasmatic nucleus (SCN). The positive clock arm was increased by diabetes with higher amplitude of circadian locomotor output cycles kaput (CLOCK) and brain and muscle aryl-hydrocarbon receptor nuclear translocator-like 1 (bmal1) and phase shift in bmal1 rhythmic oscillations in the retina; and higher bmal1 amplitude in the SCN. Peroxisome proliferator-activated receptor (PPAR) α exhibited rhythmic oscillation in retina and liver; PPARγ had lower amplitude in diabetic liver; sterol regulatory element-binding protein (srebp) 1c had higher amplitude in the retina but lower in the liver in STZ- induced diabetic animals. Both of Elongase (Elovl) 2 and Elovl4 had a rhythmic oscillation pattern in the control retina. Diabetic retinas lost Elovl4 rhythmic oscillation and had lower amplitude of Elovl2 oscillations. In line with the in vivo data, circadian expression levels of CLOCK, bmal1 and srebp1c had higher amplitude in rat REC (rREC) isolated from diabetic rats compared with control rats, while PPARγ and Elovl2 had lower amplitude in diabetic rREC. In conclusion, diabetes causes dysregulation of circadian expression of clock genes and the genes controlling lipid metabolism in the retina with potential implications for the development of diabetic retinopathy.     

Genetic and molecular study of the inability of the yeast Kluyveromyces lactis var. drosophilarum to ferment lactose

The fermentation of lactose (Lac⁺) in the dairy yeast Kluyveromyces lactis var. lactis is controlled by the LAC4 (β-galactosidase) and LAC12 (lactose permease) genes. The complementation analysis of twelve Kl. lactis var. drosophilarum natural homothallic Lac^? strains of different origin was carried out using the genetic heterothallic lines of Kl. lactis var. lactis of the lac4LAC12 and LAC4lac12 genotypes. It was shown that the natural Lac^? strains did not possess the LAC4LAC12 gene cluster. Southern hybridization of chromosomal DNA with LAC4 and LAC12 probes, as well as recombination analysis, showed that Kl. lactis var. drosophilarum yeasts do not have even silent copies of these genes. As distinct from this yeast, natural Lac^? strains of the yeast Kl. marxianus are mutants impaired in the lactose permease gene (lac12 analogue), but possess an active β-galactosidase gene (LAC4 analogue). The origin of the LAC4LAC12 gene cluster of the dairy yeasts Kl. lactis is discussed.     

Some variations in the composition of suberin from the cork layers of higher plants

The monomeric composition of the suberins from 16 species of higher plants was determined by chromatographic methods following depolymerization of the isolated extractive-free cork layers with sodium methoxide-methanol. 1-Alkanols (mainly C₁₈C₂₈), alkanoic (mainly C₁₆C₃₀), α,ω-alkanedioic (mainly C₁₆C24), ω-hydroxyalkanoic (mainly C₁₆C₂₁), dihydroxyhexadecanoic (mainly 10,16-dihydroxy- and 16-dihydroxyhexadecanoic), monohydroxyepoxyalkanoic (9,10-epoxy-18-hydroxyoctadecanoic), trihydroxyalkanoic (9,10, 18-trihydroxyoctadecanoic), epoxyalkanedioic (9,10-epoxyoctadecane-1,18-dioic) and dihydroxyalkanedioic (9,10-dihydroxyoctadecane-1 18-dioic) acids were detected in all species. The suberins differed from one another mainly in the relative proportions of these monomer classes and in the homologue content of their 1-alkanol, alkanoic, α,ω-alkanedioic and ω-hydroxyalkanoic acid fractions. C₁₈ epoxy and vic-diol monomers were major components (32–59%) of half of the suberins examined (Quercus robur, Q. ilex, Q. suber, Fagus sylvatica, Castanea sativa, Betula pendula, Acer griseum, Fraxinus excelsior) where as ω-hydroxyalkanoic and α,ω-alkanedioic acids predominated in those that contained smaller quantities of such polar C₁₈ monomers (Acer pseudoplatanus, Ribes nigrum, Euonymus alatus, Populus tremula, Solanum tuberosum, Sambucus nigra, Laburnum anagyroides, Cupressus leylandii). All species, however, contained substantial amounts (14–55 %) of ω-hydroxyalkanoic acids, the most common homologues being 18:1 (9) and 22: 0. The dominant α,ω-alkanedioic acid homologues were 16: 0 and 18: 1 (9) whereas 22: 0, 24: 0 and 26: 0, and 20: 0, 22: 0 and 24: 0 were usually the principal homologues in the 1-alkanol and alkanoic acid fractions, respectively. The most diagnostic feature of the suberins examined was the presence of monomers greater than C₁₈ in chain length; most of the C₁₆ and C₁₈ monomers identified in the suberins also occur in plant cutins emphasizing the close chemical similarity between the two anatomical groups of lipid biopolymer.     

Analysis of the cytochrome P450 1A1 (CYP1A1) gene polymorphism in the ethnic groups of the republic of Bashkortostan

In three ethnic groups from the Republic of Bashkortostan, Russians (N = 451), Tatars (N= 333), and Bashkirs (N = 171), allele, genotype, and haplotype frequency distribution patterns of the CYP1A1 gene single nucleotide polymorphisms, A2455G and T33801C, were investigated. Substantial interethnic differences in the allele frequency distribution patterns of the CYP1A1 polymorphisms A2455G and T3801C (χ ² = 15.61, d.f. = 2, P = 0.0001; and χ ² = 22.10, d.f. = 2, P = 0.0001, respectively) were observed. Pairwise comparison showed that ethnic groups of Tatars and Russians were similar in the A2455G allele frequencies (χ ² = 1.10, d.f. = 1, P = 0.30). However, in case of the T3801C marker, statistically significant differences were revealed (χ ² = 4.56, d.f. = 1, P = 0.032). At the same time, Bashkir ethnic group was found to be statistically significantly different from Russians and Tatars in the CYP1A1 polymorphic allele frequency distribution patterns (χ ² = 15.74, d.f. = 2, P = 0.0001; and χ ² = 7.47, d.f. = 1, P = 0.024, for A2455G, and χ ² = 6.46, d.f. = 1, P = 0.011; and χ ² = 21.36, d.f. = 1, P = 0.0001, for T3801C). Analysis of the CYP1A1 haplotype diversity showed that in terms of the CYP1A1 haplotype frequency distribution patterns, Bashkir ethnic group was statistically significantly different from both Russians (χ ² = 30.07, d.f. = 3, P = 0.0001) and Tatars (χ ² = 11.28, d.f. = 3, P = 0.013). The differences observed were caused by the high frequency of haplotype CYP1A1*2B, which was represented by a combination of rare alleles of the CYP1A1 polymorphisms A2455G and T3801C in Bashkirs (5.81%). On the other hand, the ethnic groups of Russians and Tatars residing in the Republic of Bashkortostan were characterized by similar frequencies of the CYP1A1 haplotypes (χ ² = 6.322, d.f. = 3, P = 0.127). The data obtained could be used in further investigations of the genetic bases of ecology dependant diseases and in the risk groups in the Republic of Bashkortostan.     

Characterization of Streptomyces argillaceus genes encoding a polyketide synthase involved in the biosynthesis of the antitumor mithramycin

Mithramycin (Mtm) is an aromatic polyketide which shows antibacterial and antitumor activity. From a chromosomal cosmid library of Streptomyces argillaceus, a Mtm producer, a clone (cosAR7) was isolated by homology to the actI/III region of S. coelicolor and the strDEM genes of S. griseus. From this clone, a 5.3-kb DNA region was sequenced and found to encode six open reading frames (designated as mtmQXPKSTI), five of them transcribed in the same direction. The deduced products of five of these genes resembled components of type-II polyketide synthases. The mtm genes would code for an aromatase (mtmQ), a polypeptide of unknown function (mtmX), a β-ketoacylsynthase (mtmP) and a related ‘chain length factor’ (mtmK), an acyl carrier protein (mtmS) and a β-ketoreductase (mtmT1). The involvement of this gene cluster in Mtm biosynthesis was demonstrated by the Mtm non-producing phenotype of mutants generated in two independent insertional inactivation experiments.     

The nucleus of the lapillar otolith discriminates the early life stages of Boreogadus saida and Arctogadus glacialis

Polar cod (Boreogadus saida) and ice cod (Arctogadus glacialis) are sympatric on continental shelves of the Arctic Ocean. The larvae and early juveniles of the two species are similar, and discrimination based on morphology and pigmentation is uncertain. We present a discrimination criterion based on the difference in lapillus nucleus size between genetically identified B. saida (n = 441, 4.2–55.0 mm standard length) and A. glacialis (n = 82, 8.6–45.5 mm). The product of the shortest and longest diameters of the nucleus (SN × LN) was 58 % larger in A. glacialis than in B. saida. The logistic regression (Ln[p/(1 ? p)] = 0.02687SN × LN ? 17.5466), where p is the probability that the fish is A. glacialis, correctly reassigned 501 of the 523 fishes (96 %) used to build the model to their genetically determined species (99 % of B. saida and 80 % of A. glacialis). The same regression correctly classified 97 % of 189 fish sampled in 2002 and 2003 and not used in building the model (99 % of B. saida and 89 % of A. glacialis).     

On the validity of Epeorella Ulmer, 1939 (Ephemeroptera,Heptageniidae) with general considerations on the Heptageniidae of the Sunda Islands

The type material of Epeorella borneonia Ulmer, 1939, the sole species of the genus Epeorella Ulmer, 1939 is reinvestigated and a lectotype (male imago) is designated. Based on several morphological structures, the synonymy with Epeorus Eaton, 1881 (Rhithrogeninae) is rejected. Epeorella stat. prop., known only at the winged stages, belongs to the subfamily Ecdyonurinae, and is a probable endemic of the island of Borneo. The newly erected genus Darthus Webb & McCafferty, 2007, also endemic to Borneo and only known by one species at the nymphal stage, is shown to be a junior subjective synonym of Epeorella. The new combination Epeorella vadora (Webb & McCafferty, 2007) is proposed for the species. The distribution of known heptageniid species from the Sunda Islands is discussed.     

Analyzing the relation between the microbial diversity of DaQu and the turbidity spoilage of traditional Chinese vinegar

Vinegar is a traditional fermented condiment, and the microbial diversity of DaQu makes the quality of vinegar products. Recently, turbidity spoilage of vinegar sharply tampered with the quality of vinegar. In this study, the relation between the microbial diversity of DaQu and turbidity spoilage of vinegar was analyzed by plating technique, PCR–denaturing gradient gel electrophoresis (DGGE), and high-performance liquid chromatography (HPLC). The 16S rRNA sequencing and DGGE analysis indicated that Bacillus (Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus thuringiensis) and Lactobacillus (including Lactobacillus acidipiscis and Lactobacillus pobuzihii) species were the dominant contaminants in vinegar products. Meanwhile, DGGE analysis showed that the dominant bacteria in DaQu belonged to genera Bacillus, Lactobacillus, Pseudomonas, Weissella, Saccharopolyspora, Enterobacter, and Pantoea. However, only two yeast species (Pichia kudriavzevii and Saccharomycopsis fibuligera) and seven mold species including Aspergillus oryzae, Aspergillus niger, Aspergillus candidus, Rhizopus microspores, Eurotium herbariorum, Absidia corymbifera, and Eupenicillium javanicum were detected in the DaQu. The population level of fungi was below 5 log CFU/g in DaQu. The chemical and physical properties of vinegar and sediments were also determined. On the basis of a combined microbial diversity-chemical analysis, we demonstrated that turbidity spoilage of vinegar was a result of cooperation among the low population level and abundance of fungal species in DaQu, the suitable climate conditions, and the contaminants in vinegar. This is the first report to analyze the relation between the microbial diversity of DaQu and turbidity spoilage of vinegar.     

Antagonistic Gene Activities Determine the Formation of Pattern Elements along the Mediolateral Axis of the Arabidopsis Fruit

The Arabidopsis fruit mainly consists of a mature ovary that shows three well defined territories that are pattern elements along the mediolateral axis: the replum, located at the medial plane of the flower, and the valve and the valve margin, both of lateral nature. JAG/FIL activity, which includes the combined functions of JAGGED (JAG), FILAMENTOUS FLOWER (FIL), and YABBY3 (YAB3), contributes to the formation of the two lateral pattern elements, whereas the cooperating genes BREVIPEDICELLUS (BP) and REPLUMLESS (RPL) promote replum development. A recent model to explain pattern formation along the mediolateral axis hypothesizes that JAG/FIL activity and BP/RPL function as antagonistic lateral and medial factors, respectively, which tend to repress each other. In this work, we demonstrate the existence of mutual exclusion mechanisms between both kinds of factors, and how this determines the formation and size of the three territories. Medial factors autonomously constrain lateral factors so that they only express outside the replum, and lateral factors negatively regulate the medially expressed BP gene in a non-autonomous fashion to ensure correct replum development. We also have found that ASYMMETRIC LEAVES1 (AS1), previously shown to repress BP both in leaves and ovaries, collaborates with JAG/FIL activity, preventing its repression by BP and showing synergistic interactions with JAG/FIL activity genes. Therefore AS gene function (the function of the interacting genes AS1 and AS2) has been incorporated in the model as a new lateral factor. Our model of antagonistic factors provides explanation for mutant fruit phenotypes in Arabidopsis and also may help to understand natural variation of fruit shape in Brassicaceae and other species, since subtle changes in gene expression may cause conspicuous changes in the size of the different tissue types.     

Resolution of the long-standing controversy over the type species of the genus Pseudotypotherium (Notoungulata,Typotheria, Mesotheriidae)

Mesotheres (Notoungulata: Typotheria) are among the most common mammals found in upper Miocene to Pliocene deposits of central Argentina, including the classic type Monte Hermoso locality, which defines the Montehermosan South American Land Mammal “Age”. Nevertheless, the correct name for the mesothere species from this site has been shrouded in uncertainty for well over a century due to questions of taxonomic priority, specimen provenance, and ontogenetic changes in dental formula. Since the mesotheres from Monte Hermoso were named, three distinct species have been formally considered as the type species of the genus: (1) Pseudotypotherium bravardi; (2) “Pseudotypotherium” maendrum; and (3) Pseudotypotherium exiguum. However, none of these species is a nominal species of the Pseudotypotherium genus; all three were originally referred to Typotherium. Article 67.2 of the International Code of Zoological Nomenclature (ICZN, 1999) indicates that only species considered as nominal species are eligible to set the type; in the case of Pseudotypotherium, these include: P. pulchrum, P. carlesi, P. hystatum, and P. carhuense. We conclude that Pseudotypotherium pulchrum F. Ameghino, 1904 (holotype MACN A 10299, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Ameghino Collection), is the type species of the mesotheriid notoungulate genus from Monte Hermoso. According to Article 68.2, F. Ameghino fixed the type by original designation in 1904 when he described P. pulchrum and included “n. g., n. sp.”. Two of the other species previously considered species P. (= T.) bravardi and P. (= T.) exiguum are invalid as type species according to Article 70.2, since their designations overlooked the previous type fixation. The third species (M. (= T.) maendrum) represents a different mesothere genus (Mesotherium) that only occurs in younger (Pleistocene) deposits. Our analysis puts an end to a historical debate that has been ongoing for more than a century regarding the identity of this well-represented late Miocene–Pliocene mesotheriine genus (Pseudotypotherium). This study provides a solid taxonomic foundation for future studies on intraspecific and ontogenetic variation of Pseudotypotherium pulchrum.     

Trematodes Recovered in the Small Intestine of Stray Cats in the Republic of Korea

In 2005, we reported the infection status of 438 stray cats with various species of intestinal helminths, including nematodes (4 species), trematodes (23 species), and cestodes (5 species) in the Republic of Korea. However, morphologic details of each helminth species have not been provided. In the present study, we intended to describe morphologic details of 13 trematode species which were either new fauna of cats (10 species) or new fauna of not only cats but also all animal hosts (3 species). The worms were fixed in 10% neutral buffered formalin under a cover slip pressure, stained with Semichon''s acetocarmine, and then observed using a light microscope equipped with a micrometer. The 13 subjected species included members of the Heterophyidae (Stellantchasmus falcatus, Stictodora fuscata, Stictodora lari, Centrocestus armatus, Procerovum varium, and Cryptocotyle concava), Echinostomatidae (Echinostoma hortense, Echinostoma revolutum, Echinochasmus japonicus, and Stephanoprora sp.), Diplostomidae (Neodiplostomum seoulense), Plagiorchiidae (Plagiorchis muris), and Dicrocoeliidae (Eurytrema pancreaticum). By the present study, Cryptocotyle sp. and Neodiplostomum sp. recored in our previous study were identified as C. concava and N. seoulense, respectively. Three species, P. varium, C. concava, and Stephanoprora sp., are new trematode fauna in Korea.     

Glutamate-induced polymerization of tubulin: characteristics of the reaction and application to the large-scale purification of tubulin

The multiple attack model of the α-amylase mechanism has been analyzed. Theoretical rate coefficients dependent on the degree of polymerization of substrate (n) have been applied. They are: effectiveness of hydrolysis (y_n) which affects V values, and the average number of unitary movements (ζ_n) which affects K_m values. The model explains the dependence of V and K_m on the degree of polymerization of substrates with n values higher than the number of subsites in the enzyme binding site. Distribution of the degree of polymerization of hog pancreas α-amylase products (n_p) and average n_p value has been found experimentally and applied to calculate the maximal number of unitary movements (z) of the enzyme during the single enzyme-substrate meeting. V and K_m values of hog pancreas α-amylase for amylose and different branched substrates have been determined and discussed in terms of the multiple attack theory. Their dependence on theoretic y_n and ζ_n values has been found in support of the model.