Floral organogenesis in Tetracentron sinense (Trochodendraceae) and its systematic significance

In Tetracentron sinense of the basal eudicot family Trochodendraceae, the flower primordium, together with the much retarded floral subtending bract primordium appear to form a common primordium. The four tepals and the four stamens are initiated in four distinct alternating pairs, the first tepal pair is in transverse position. The four carpels arise in a whorl and alternate with the stamens. This developmental pattern supports the interpretation of the flower as dimerous in the perianth and androecium, but tetramerous in the gynoecium. There is a relatively long temporal gap between the initiation of the stamens and the carpels. The carpel primordia are then squeezed into the narrow gaps between the four stamens. In contrast to Trochodendron, the residual floral apex after carpel formation is inconspicuous. In their distinct developmental dimery including four tepals and four stamens, flowers of Tetracentron are reminiscent of other, related basal eudicots, such as Buxaceae and Proteaceae.     

A new peronosporomycete, <Emphasis Type="Italic">Halioticida noduliformans</Emphasis> gen. et sp. nov., isolated from white nodules in the abalone <Emphasis Type="Italic">Haliotis</Emphasis> spp. from Japan

Four strains belonging to the Peronosporomycetes (formerly Oomycetes) were isolated from white nodules found on the mantle of three species of abalone. In artificial seawater, the four isolates formed fragments such as in the genus Haliphthoros, but the protoplasm constriction was weaker, and fragments were longer, with smaller spaces between them, than those of Haliphthoros. The four strains form one or more discharge tubes from each zoosporangium. The four strains were similar, but not identical, to the genus Haliphthoros based on morphological characteristics. As a result, the four isolates were classified in a new genus and species, Halioticida noduliformans gen. et sp. nov. Phylogenetic analysis of the D1/D2 region of the large subunit ribosomal RNA gene (LSU rDNA) was performed, and the four isolates showed 100%–99.8% concordance. In the phylogenetic tree, the four isolates were not classified in the subclass Peronosporomycetidae, Saprolegniomycetidae, or Rhipidiomycetidae. However, the four isolates formed a new clade with genera Haliphthoros and Halocrusticida in Peronosporomycetes. Within this new clade, the four isolates, Haliphthoros spp. and Halocrusticida spp., were grouped in their respective independent subclades. These results showed that these were the new genus and species from the morphological characteristics.     

Incompatibility and molecular relationships between small staphylococcal plasmids carrying the same resistance marker

Incompatibility relationships between staphylococcal plasmids carrying the same, single resistance marker were studied by means of appropriate recombinant plasmids. Naturally occurring plasmids encoding streptomycin, tetracycline, or chloramphenicol resistance, respectively, were used in this study, four of each phenotype. The plasmids responsible for tetracycline resistance proved to belong to a single incompatibility set. Similarly, the four streptomycin resistance plasmids fall in the same incompatibility set. On the other hand, plasmids encoding chloramphenicol resistance were divided in four distinct incompatibility sets, three of them being newly defined. Study of the molecular relationships between these plasmids by DNA-DNA hybridization and restriction endonuclease cleavage supported the conclusions from genetic tests that the four Tc^r and the four Sm^r plasmids are essentially identical, whereas the four Cm^r plasmids are diverse.     

Discovery of four natural clones in a crayfish species Procambarus clarkii

Self-cloning is quite rare in shrimp, lobsters, crayfish and crabs. Here we report the discovery of four natural clones of red swamp crayfish (Procambarus clarkii), each containing 2-6 genetically identical individuals, during the genotyping of 120 individuals with five microsatellites. The four clones were heterozygote at most of the five microsatellite loci. Phylogenetic analysis using microsatellite genotypes suggests recent origin of the four clones. Sequencing a part of the mitochondrial gene Cox I confirmed that the four clones were from the species Procambarus clarkii.     

The Shark HoxN Cluster Is Homologous to the Human HoxD Cluster

The statistical analysis of phylogenetic footprints in the two known horn shark Hox clusters and the four mammalian clusters shows that the shark HoxN cluster is HoxD-like. This finding implies that the most recent common ancestor of jawed vertebrates had at least four Hox clusters, including those which are orthologous to the four mammalian Hox clusters.     

Host-symbiont interactions.I. The lectins of legumes interact with the O-antigen-containing lipopolysaccharides of their symbiont Rhizobia

A specific interaction between the O-antigen-containing lipopolysaccharides of $\text{Rhizobia}$ and the lectins of their legume hosts has been demonstrated. The lectins have been purified from the seeds of four legumes and the lectins covalently attached to Agarose. The lipopolysaccharides were isolated from the four $\text{Rhizobial}$ symbionts of the legumes. These four lipopolysaccharides were passed through the four lectin columns. In each case, the lipopolysaccharide from a $\text{Rhizobium}$ interacts with the lectin column of its symbiont but not with the other lectin columns.     

Knee joint angle affects EMG–force relationship in the vastus intermedius muscle

It is not understood how the knee joint angle affects the relationship between electromyography (EMG) and force of four individual quadriceps femoris (QF) muscles. The purpose of this study was to examine the effect of the knee joint angle on the EMG–force relationship of the four individual QF muscles, particularly the vastus intermedius (VI), during isometric knee extensions. Eleven healthy men performed 20–100% of maximal voluntary contraction (MVC) at knee joint angles of 90°, 120° and 150°. Surface EMG of the four QF synergists was recorded and normalized by the root mean square during MVC. The normalized EMG of the four QF synergists at a knee joint angle of 150° was significantly lower than that at 90° and 120° (P < 0.05). Comparing the normalized EMG among the four QF synergists, a significantly lower normalized EMG was observed in the VI at 150° as compared with the other three QF muscles (P < 0.05). These results suggest that the EMG–force relationship of the four QF synergists shifted downward at an extended knee joint angle of 150°. Furthermore, the neuromuscular activation of the VI was the most sensitive to change in muscle length among the four QF synergistic muscles.     

Xiphinema krugi,Species Complex or Complex of Cryptic Species?

Fourteen morphologically putative populations of X. krugi were clearly separated into four different profiles by RFLP analysis (Alu I and Hinf I), sequencing of the ITS-1 region, and subsequent Maximum Likelihood phylogenetic analyses. These four profiles were further supported by a principal component analysis of morphometric characters that yielded four taxonomic clusters matching those produced by the molecular data. Sequence homology was greater amongst populations that represented the same RFLP profile than between profiles and similar both between representative populations of the RFLP profiles and putative closely related Xiphinema species. This study suggests that X. krugi is a potential species complex comprised of at least four distinct genotypes.     

Taxonomic rearrangement of the genus Ulkenia sensu lato based on morphology, chemotaxonomical characteristics, and 18S rRNA gene phylogeny (Thraustochytriaceae, Labyrinthulomycetes): emendation for Ulkenia and erection of Botryochytrium, Parietichytrium, and Sicyoidochytrium gen. nov.

The genus Ulkenia is characterized by the naked protoplast stage within its life cycle. However, the 18S rRNA gene tree clearly shows that this genus is not a natural taxon, because our own isolates and reported strains separately form four well-supported monophyletic groups. These four groups are clearly distinguishable by their profiles of polyunsaturated fatty acids and carotenoid pigments and cell and colony morphology, e.g., persistence of sporangial wall, manner of the cell cleavage at the zoospore formation, and development of the ectoplasmic nets. Therefore, the four groups are assigned to four genera including three new genera, i.e., Ulkenia sensu stricto, Botryochytrium, Parietichytrium, and Sicyoidochytrium gen. nov.     

An attempt to measure selection coefficients affecting the alcohol dehydrogenase polymorphism in Drosophila melanogaster populations maintained on ethanol media

Eleven populations polymorphic for Adh F and S alleles were established from wild-caught D. melanogaster. Seven of the populations were founded from mass collections each of several hundred flies and the other four were isofemale lines. Subcultures from all eleven were maintained on one of four different types of medium—standard laboratory medium, standard media supplemented to 3% or 9% (v/v) ethanol, and simulated wine seepages. These subcultures were rescored for F and S gene frequencies after 10, 20 and 30 generations. Maximum-likelihood methods were then used to estimate selection coefficients among the Adh genotypes and analyses of deviance were carried out to test the coefficients against hypotheses of neutrality and various modes of selection. No significant selective changes in Adh frequencies were observed in the seven mass cultures on any of the four different media types. However, highly significant selective effects were detected in the four isofemale lines; these effects were homogeneous across the four lines and the four media types and the underlying fitness set was estimated as 1.00:1.04:1.09 for S/S:F/S:F/F.     

Multiple species of methionyl-tRNA from mouse liver mitochondria

Methionyl tRNA acylated within mitochondria isolated from mouse liver, has been resolved into four species by RPC-5 chromatography. All four elute prior to the three cytoplasmic methionyl tRNA species. Of the four species, two are formylated. These results suggest that iso-accepting species of met-tRNA^met exist in mouse liver mitochondria.     

Microsatellite loci for distinguishing spotted owls (Strix occidentalis), barred owls (Strix varia), and their hybrids

We identified four diagnostic microsatellite loci that distinguish spotted owls (Strix occidentalis), barred owls (Strix varia), F₁ hybrids and backcrosses. Thirty‐four out of 52 loci tested (65.4%) successfully amplified, and four of these loci (11.8%) had allele sizes that did not overlap between spotted and barred owls. The probability of correctly identifying a backcross with these four loci is 0.875. Genotyping potential hybrid owls with these markers revealed that field identifications were often wrong. Given the difficulty of identifying hybrids in the field, these markers will be useful for hybrid identification, law enforcement and spotted owl conservation.     

腹腔镜子宫切除术的临床效果及应用价值研究

目的:探讨腹腔镜子宫切除术的临床效果和应用价值。方法:将720例因子宫病变有子宫切除指征患者随机分成腹腔镜组和开腹组,并按照腹腔镜手术指征选择4种不同的手术方式,对比腹腔镜子宫次全切除术、腹腔镜筋膜内子宫切除术、腹腔镜辅助阴式子宫切除术、全腹腔镜子宫切除术和开腹组间手术成功率、并发症发生率、术中及恢复情况和全身炎症反应综合症方面的差异。结果:腹腔镜四组手术成功率都在95%以上,远大于开腹组手术成功率(87.4%)(P<0.05)。腹腔镜四组并发症发生率远小于开腹组(P<0.05)。腹腔镜四组在手术成功率和并发症发生率方面差异无统计学意义(P>0.05)。腹腔镜四组在手术时间、术中出血量、住院天数及住院费用方面均低于开腹组(P<0.05)。而腹腔镜四组间比较差异均无统计学意义(P>0.05)。腹腔镜四组全身炎症反应综合症发生率和持续时间均低于开腹组(P<0.05),而腹腔镜四组间比较差异则无统计学意义(P>0.05)。结论:腹腔镜子宫切除术临床效果较好,安全有效,创伤小,费用低,适合符合手术指证的患者应用。     

Comparative physiology of nitrogenase activity and vesicle development for Frankia strains CpI1, ACN1 ag,EAN1pec and EUN1f

The relationship between nitrogen fixation and development of a specialized cell structure, called the vesicle, was studied using four Frankia isolates. Nitrogenase activity was repressed in all four strains during growth with ammonia. Strain CpI1 formed no vesicles during NH₄ growth. Strains ACN1 ^ag , EAN1_pec and EUN1_f produced low numbers of vesicles in the presence of ammonia. Following transfer to nitrogen-free media, a parallel increase in nitrogenase activity and vesicle numbers occurred with all four isolates. Appearance of nitrogenase activity was more rapid in those strains that possessed some vesicles at the time of shift to N₂ as a nitrogen source. The ratio of vesicle numbers to level of nitrogenase activity varied widely among the four strains and in response to different growth conditions and culture age of the individual strains. Optimum conditions of temperature, carbon and energy source, nitrogen source and availability of iron and molybdenum were different for each of the four strains. Those conditions that significantly reduced nitrogenase activity were always associated with decreased numbers of vesicles.     

Babesia bovis: successful vaccination against homologous challenge in splenectomised calves using a fraction of haemagglutinating antigen

A soluble extract from lysed bovine erythrocytes infected with Babesia bovis, was separated by preparative agarose electrophoresis. A fraction with a mobility of plasma β globulins was shown to contain babesial antigen confined mainly to the infected erythrocyte and was used to vaccinate a group of four calves. Following challenge with homologous B. bovis all four calves vaccinated with the antigen survived the infection whereas all the calves in a control group of four died from infection.     

Molecular phylogenetic relationships among Sichuan snub-nosed monkeys (Rhinopithecus roxellanae) inferred from mitochondrial cytochrome-b gene sequences

The Sichuan snub-nosed monkey (Rhinopithecus roxellanae) is a species endemic to China, and its distribution is the widest among all snub-nosed monkeys in China. To clarify whether there is subspecific differentiation within this species, we determined partial sequences of the cytochrome-b gene from four populations ofR. roxellanae. First, 402bps of the partial sequences fromR. roxellanae were compared with those fromR. bieti andR. avunculus, and the phylogenetic tree was constructed by the neighbor-joining method. The genetic distance was only 0–0.002 among the four populations, and their sequences constituted a monophyletic group. Further, comparison of longer sequences (735bp) among the four populations revealed that there were only four substitutions and the genetic distance was only 0.001–0.005 among them. Thus, we suggest that, at least on mtDNA phylogeny, the difference among the four populations does not reach the subspecies level, and that this species should be recognized as a monotypic species.     

Characterizations of four toll‐like receptor 4s in grass carp Ctenopharyngodon idellus and their response to grass carp reovirus infection and lipopolysaccharide stimulation

In this study, the subcellular localization, tissue distribution and response to grass carp reovirus (GCRV) infection and lipopolysaccharide (LPS) stimulation of four grass carp Ctenopharyngodon idellus toll‐like receptor 4 (tlr4) genes were investigated. All four genes were constitutively expressed in all tissues studied, but the subcellular localization and tissue exhibiting the highest expression differed for each protein. Following GCRV infection, all the four tlr4s were upregulated in all tissues examined, and stimulation of C. idellus kidney (CIK) cells with LPS resulted in downregulation of all four tlr4s. These results provide a foundation for further investigation of tlr4 genes in bony fishes.     

Inconsistencies of interannual variability and trends in long‐term satellite leaf area index products

Understanding the long‐term performance of global satellite leaf area index (LAI) products is important for global change research. However, few effort has been devoted to evaluating the long‐term time‐series consistencies of LAI products. This study compared four long‐term LAI products (GLASS, GLOBMAP, LAI3g, and TCDR) in terms of trends, interannual variabilities, and uncertainty variations from 1982 through 2011. This study also used four ancillary LAI products (GEOV1, MERIS, MODIS C5, and MODIS C6) from 2003 through 2011 to help clarify the performances of the four long‐term LAI products. In general, there were marked discrepancies between the four long‐term LAI products. During the pre‐MODIS period (1982–1999), both linear trends and interannual variabilities of global mean LAI followed the order GLASS>LAI3g>TCDR>GLOBMAP. The GLASS linear trend and interannual variability were almost 4.5 times those of GLOBMAP. During the overlap period (2003–2011), GLASS and GLOBMAP exhibited a decreasing trend, TCDR no trend, and LAI3g an increasing trend. GEOV1, MERIS, and MODIS C6 also exhibited an increasing trend, but to a much smaller extent than that from LAI3g. During both periods, the R² of detrended anomalies between the four long‐term LAI products was smaller than 0.4 for most regions. Interannual variabilities of the four long‐term LAI products were considerably different over the two periods, and the differences followed the order GLASS>LAI3g>TCDR>GLOBMAP. Uncertainty variations quantified by a collocation error model followed the same order. Our results indicate that the four long‐term LAI products were neither intraconsistent over time nor interconsistent with each other. These inconsistencies may be due to NOAA satellite orbit changes and MODIS sensor degradation. Caution should be used in the interpretation of global changes derived from the four long‐term LAI products.     

Mapping the four‐horned locus and testing the polled locus in three Chinese sheep breeds

Four‐horned sheep are an ideal animal model for illuminating the genetic basis of horn development. The objective of this study was to locate the genetic region responsible for the four‐horned phenotype and to verify a previously reported polled locus in three Chinese breeds. A genome‐wide association study (GWAS) was performed using 34 two‐horned and 32 four‐horned sheep from three Chinese indigenous breeds: Altay, Mongolian and Sishui Fur sheep. The top two significant single nucleotide polymorphisms (SNPs) associated with the four‐horned phenotype were both located in a region spanning positions 132.6 to 132.7 Mb on sheep chromosome 2. Similar locations for the four‐horned trait were previously identified in Jacob, Navajo‐Churro, Damara and Sishui Fur sheep, suggesting a common genetic component underlying the four‐horned phenotype. The two identified SNPs were both downstream of the metaxin 2 (MTX2) gene and the HOXD gene cluster. For the top SNP—OAR2:g.132619300G>A—the strong associations of the AA and AG genotypes with the four‐horned phenotype and the GG genotype with the two‐horned phenotype indicated the dominant inheritance of the four‐horned trait. No significant SNPs for the polled phenotype were identified in the GWAS analysis, and a PCR analysis for the detection of the 1.8‐kb insertion associated with polled sheep in other breeds failed to verify the association with polledness in the three Chinese breeds. This study supports the hypothesis that two different loci are responsible for horn existence and number. This study contributes to the understanding of the molecular regulation of horn development and enriches the knowledge of qualitative traits in domestic animals.