Electrophoretic and immunologic characterization of proteins of merozoites of Eimeria acervulina, E. maxima, E. necatrix, and E. tenella.

Merozoites of Eimeria acervulina, Eimeria maxima, Eimeria necatrix, and Eimeria tenella were compared by gel electrophoresis, western-blotting with chicken antiserum, indirect fluorescent antibody reactions, and antiserum neutralization. Merozoites from the 4 species had dissimilar patterns of proteins and antigens in soluble and membrane fractions. Coomassie blue staining of SDS-PAGE gels revealed 16-22 protein bands depending on the species of merozoite but only 3 bands per species in the membrane fractions. Homologous and heterologous antisera recognized 5-12 soluble fraction bands and 3-7 membrane fraction bands on immunoperoxidase-stained western blots, depending on the species. When antisera from infected chickens were used in an indirect fluorescent antibody reaction, the merozoites of E. tenella and E. necatrix had a strong reaction with homologous and heterologous antisera. Merozoites of E. acervulina and E. maxima reacted with homologous antisera but had a weak or no reaction with heterologous antisera. Chicken antiserum against E. tenella had no effect on the viability of E. tenella merozoites when they were inoculated into chicken embryos.     

Genomic constitutions of four Chinese endemic Elymus species: E. brevipes, E. yangii, E. anthosachnoides, and E. altissimus (Triticeae, Poaceae).

The objectives of this study were to determine the genomic constitution and to explore the genomic variation within four Chinese endemic Elymus species, i.e., E. brevipes (Keng) L?ve (2n = 4x = 28) and E. yangii B.R. Lu (2n = 4x = 28), E. anthosachnoides (Keng) L?ve (2n = 4x = 28), and E. altissimus (Keng) L?ve (2n = 4x = 28). Intraspecific crosses between different populations of the four Elymus species, as well as interspecific hybridizations among the four target species, and with six analyzer species containing well-known genomes, i.e., E. caninus (L.) L. (2n = 4x = 28, SH), E. sibiricus L. (2n = 4x = 28, SH), E. semicostatus (Lees ex Steud.) Melderis (2n = 4x = 28, SY), E. parviglumis (Keng) L?ve (2n = 4x = 28, SY), E. tsukushiensis Honda (2n = 6x = 42, SHY), and E. himalayanus (Nevski) Tzvelev (2n = 6x = 42, SHY), were achieved through the aid of embryo rescue. Chromosome pairing behaviors were studied in the parental species and their hybrids. Numerical analysis on chromosome pairing was made on the interspecific hybrids. With one exception, each meiotic configuration at metaphase I in the hybrids involving the target taxa and the analyzer species containing the "SH" genomes fit a 2:1:1 model with x-values ranging between 0.91 and 1.00; chromosome pairing in the hybrids involving analyzer parents with the "SY" genomes match a 2:2 model, with x-values between 0.97 and 0.99. All pentaploid hybrids with a genomic formula "SSYYH," except for two crosses having unexpected low c-values, had pairing patterns fitting the 2:2:1 model with x-values varying between 0.96 and 1.00. It is concluded based on hybridization, fertility, and chromosome pairing data that (i) the four target Elymus species are strictly allotetraploid taxa, (ii) they are closely related species, all comprised of the "SY" genomes, (iii) minor genomic structural rearrangements have occurred within the four Elymus species, and (iv) meiotic pairing regulator(s) exists in some of the Elymus taxa studied.     

Differentiation and identification of Enterococcus durans, E. hirae and E. villorum

AIMS: To compare different tests in the identification of Enterococcus durans, E. hirae and E. villorum strains. These bacteria belong to the E. faecium species group and are phylogenetically closely related, as evidenced by 16S rRNA sequence homologies of over 98.8%. METHODS AND RESULTS: Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis of whole-cell protein, tRNA interpacer polymerase chain reaction (PCR) and arbitrarily-primed (D11344-primed AP) -PCR analysis correctly identified all three species in a collection of strains from very diverse origins. In contrast, biochemical reactions only allowed the unequivocal differentiation of the three species as a group from the other enterococci. Within this group, D-xylose acidification can be used to differentiate E. villorum, but exceptions occur. Strains highly susceptible to clindamycin can be identified as E. durans, but many strains of this species cannot be differentiated from E. hirae and E. villorum due to acquired resistance. CONCLUSIONS: Despite their close relationship, E. durans, E. hirae and E. villorum can be differentiated by genomic methods and by whole-cell protein analysis. SIGNIFICANCE AND IMPACT OF THE STUDY: Only a minority of strains of these three enterococcal species can be identified reliably by the currently available and commonly applied phenotypic tests.     

Molecular diversity and relationships among Elymus trachycaulus, E. subsecundus, E. virescens, E. violaceus, and E. hyperarcticus (Poaceae: Triticeae) as determined by amplified fragment length polymorphism.

Morphological similarity among E. trachycaulus, E. virescens, E. violaceus, and E. hyperarcticus has often been noted. Taxonomists have tried to discriminate among these taxa using morphological characters and a number of different relationships among them have been suggested. However, the genetic relationships among these taxa are still unknown. AFLP analysis was used to characterize the molecular diversity of these taxa and to examine genetic relationships among them. A high degree of genetic identity was apparent among 7 accessions of E. virescens. The similarity values ranged from 0.90 to 0.99 with an average of 0.94. The mean similarity values among 3 E. hyperarcticus and among 5 E. violaceus accessions were 0.84 (0.81-0.87) and 0.77 (0.66-0.90), respectively. The similarity values among 17 E. trachycaulus accessions ranged from 0.49 to 0.92 with an average of 0.75. The 5 accessions of E. subsecundus displayed high variation, with similarity values between 0.52 and 0.68 and a mean value of 0.59. Both maximum-parsimony (MP) and neighbor-joining (NJ) analyses showed that all 7 accessions of E. virescens formed a clade, indicating a monophyletic origin. On the other hand, Elymus trachycaulus, E. subsecundus, and E. violaceus were each paraphyletic and separated into different genetically distinct groups. Among these 5 taxa, E. virescens was genetically similar to E. trachycaulus, and E. violaceus was genetically similar to E. hyperarcticus.     

A comparison of the mineral composition of milk of domestic and captive wild equids (Equus przewalski, E. zebra, E. burchelli, E. caballus, E. assinus)

Milk samples were obtained in early and/or late lactation from Przewalski horses, Hartmann's zebras, Grant's zebras, domestic horses, ponies and a mule mare made pregnant by embryo transfer. Samples were compared for their content of total solids, ash, calcium, phosphorus, magnesium, sodium, potassium, copper, zinc and iron. Milk from the Przewalski horses, Hartmann's zebra and the domestic horse had similar mineral composition and the content of minerals was higher in early than in late lactation. Milk from the domestic mule contained the lowest concentration of calcium, phosphorus and zinc but the highest concentration of magnesium, sodium and potassium. Milk from the Grant's zebras contained more sodium than potassium, unlike milk from Przewalski horses, Hartmann's zebras or domestic horses in which there was more potassium than sodium.     

Latex constituents of Euphorbia candelabrum,E. grantii,E. tirucalli and Synadenium grantii

Quantitative and qualitative analyses were carried out on the latex of four Euphorbiaceae naturally growing in eastern Africa. Rubber (cis-1,4     

Morphological Identification of Elymus sibiricus,E. nutans,and E. burchan-buddae,and Their Genomic Relationships

In order to investigate morphological variations of Elymus sibiricus L., E. nutans Griseb., and E. burchan-buddae (Nevski) Tzvelev ［=Roegneria nutans (Keng) Keng］, and to explore their systematic relationships, six morphological characters were measured and compared between the Elymus species. Interspecific hybridizations between E. nutans and E. sibiricus, and E. burchan-buddae were carried out with the aid of embryo rescue. Chromosome pairing behaviour was also analysed at metaphase- I of meiosis in pollen mother cells of F₁ hybrids. Morphologic characters, such as length of spikes and length of glumes varied considerably between different individuals of each species, whereas length and width of paleas were quite stable and different between species. The interspecific hybrids were completely sterile and their meioses were irregular. Meiotic configuration of E. nutans × E. burchan-buddae was 7.70I +13.40Ⅱ+0.06Ⅲ+0.08 IV, whereas that of E. sibircus×E. nutans was 11.98I+9.61Ⅱ+0.64Ⅲ+0.39Ⅳ+0.01V. It is concluded from the morphological and cytological study that (1) it is possible to identify the three Elymus species using the palea character, in addition to other traditionally applied characters; (2) Elymus nutans and E. burchan-buddae have a comparatively high genomie relationship, while E. nutans and E. sibircus have a relatively low genomic affinity to one another; and (3) a certain chromosome pairing regulator was presented in the hybrid between E. burchan-buddae andE. nutans.     

Allozymic and morphological differentiation among three South American frogs, genus Eupsophus (E. roseus, E. insularis and E. contulmoensis).

1. Three species of the frog, genus Eupsophus, were examined using electrophoresis at 21 loci, and nine morphological characters employing discriminant and principal components analyses. 2. The allozymic and morphological differentiation patterns do not agree. 3. It is suggested that selective pressures are responsible for the incongruence of both sets of characters.     

E. E. Just's broad,yet hidden,influence on modern cell and developmental biology

This year, 2019, marks the centennial of embryologist E. E. Just's discovery of what is known as the fast block to polyspermy. Just's observation of the subtle changes that occur at the egg's surface during fertilization (and in experimental parthenogenesis) led him to postulate that the egg, and indeed every cell, possesses a property he called independent irritability, which represents the cell's ability to respond in a physiologically‐relevant way to a variety of signals or triggers. In this paper, I argue that Just's concept of independent irritability informed his contemporary Johannes Holtfreter as Holtfreter attempted to explain the phenomena of embryonic induction and competence and that Holtfreter, in turn, influenced Marc Kirschner and John Gerhart in their formulation of the theory of facilitated variation. Just's influence is especially evident in Gerhart and Kirschner's presentations of what they call weak linkage—a property of living systems that allows core processes and components to be mixed and matched in different ways to generate novel traits. Unfortunately, the connection between Holtfreter's work and Just's has remained hidden. This paper gives examples of phenomena that exhibit weak linkage, and it lays out the case that Just's concept of independent irritability, through Holtfreter, Gerhart, and Kirschner, has broadly infiltrated modern cell and developmental biology.     

Allozyme variation and conservation of the Tasmanian endemics, Eucalyptus risdonii, E. tenuiramis and E. coccifera

The rare Tasmanian endemic Eucalyptus risdonii is thought tohave arisen as a result of small, heterochronic changes to the genome ofits more widespread sister species, E. tenuiramis. Previousmorphological studies have shown that genetic differentiation betweenpopulations of E. risdonii and southern E. tenuiramisis continuous and much smaller than the separation between the southernand northern morphotypes of E. tenuiramis. However,morphological traits may be influenced by selection, possibly leading toconvergence, requiring an independent measure of genetic variation. Westudied allozyme frequency variation in E. risdonii, southernE. tenuiramis (parapatric with E. risdonii), northernE. tenuiramis (disjunct from southern populations), and E.coccifera (as an outgroup). Each morphotype had a level of geneticdiversity close to the average reported in ten other eucalypt specieswith similar distributions but the coefficients of populationdifferentiation within morphotypes were lower than in most othereucalypt species. The overall difference between morphotypes wasextremely small, possibly as a result of recent and rapiddifferentiation, but may also be the result of gene flow from otherpeppermint taxa, including E. amygdalina and E.pulchella. Southern E. tenuiramis has greater geneticaffinity with E. risdonii than with northern E.tenuiramis which supports recent evolutionary divergence of E.risdonii. In this study we have shown that taxonomic units are notnecessarily aligned with an equitable partition of the gene pool andthat conservation units should be much broader than single taxa in orderto preserve evolutionary processes.     

Negative regulation of the bovine papillomavirus E5, E6, and E7 oncogenes by the viral E1 and E2 genes.

Papillomaviruses induce benign squamous epithelial lesions that infrequently are associated with uncontrolled growth or malignant conversion. The virus-encoded oncogenes are clearly under negative regulation since papillomaviruses can latently infect cells and since different levels of viral oncogene expression are seen within the layers of differentiating infected epitheliomas. We used bovine papillomavirus type 1 (BPV-1) to investigate the mechanisms involved in the negative regulation of transformation. We found that the following two distinct and interacting mechanisms negatively regulate BPV-1 transformation effected by virally encoded trans-acting factors: (i) E2 repressors suppress transformation by the E6 and E7 oncogenes, and (ii) E1 and the E2 transactivator suppress transformation by the E6, E7, and E5 oncogenes. These systems interact in that the E2 repressors function to relieve the transformation suppression effected by the E1 and E2 transactivator genes. A BPV-1 mutant that lacked E2 repressors and E1 had greatly augmented transformation capacity. Analysis of this mutant revealed that the enhanced transformation was due to expression of the E6 and E7 genes in the absence of E5, revealing a previously unappreciated potency and synergy for the BPV-1 E6 and E7 oncogenes.