Expression of nucleolar organizer regions (NORs) in ovarian epithelial tumors

AgNOR staining technique was tested in ovarian epithelial tumors to evaluate its diagnostic potential in distinguishing between borderline tumors and well-differentiated carcinomas. In our opinion, the AgNOR count appears useful for assessing differences only between borderline and well-differentiated serous ovarian tumors at stage I of FIGO clinical advancement.     

Coevolution of Cryptosporidium tyzzeri and the house mouse (Mus musculus)

Two house mouse subspecies occur in Europe, eastern and northern Mus musculus musculus (Mmm) and western and southern Mus musculus domesticus (Mmd). A secondary hybrid zone occurs where their ranges meet, running from Scandinavia to the Black Sea. In this paper, we tested a hypothesis that the apicomplexan protozoan species Cryptosporidium tyzzeri has coevolved with the house mouse. More specifically, we assessed to what extent the evolution of this parasite mirrors divergence of the two subspecies. In order to test this hypothesis, we analysed sequence variation at five genes (ssrRNA, Cryptosporidium oocyst wall protein (COWP), thrombospondin-related adhesive protein of Cryptosporidium 1 (TRAP-C1), actin and gp60) in C. tyzzeri isolates from Mmd and Mmm sampled along a transect across the hybrid zone from the Czech Republic to Germany. Mmd samples were supplemented with mice from New Zealand. We found two distinct isolates of C. tyzzeri, each occurring exclusively in one of the mouse subspecies (C. tyzzeri-Mmm and C. tyzzeri-Mmd). In addition to genetic differentiation, oocysts of the C. tyzzeri-Mmd subtype (mean: 4.24 × 3.69 μm) were significantly smaller than oocysts of C. tyzzeri-Mmm (mean: 4.49 × 3.90 μm). Mmm and Mmd were susceptible to experimental infection with both C. tyzzeri subtypes; however, the subtypes were not infective for the rodent species Meriones unguiculatus, Mastomys coucha, Apodemus flavicollis or Cavia porcellus. Overall, our results support the hypothesis that C. tyzzeri is coevolving with Mmm and Mmd.     

Silver staining of the nucleolar organizer regions (NORs) in semithin Lowicryl sections

The one-step silver technique was applied to semithin Lowicryl sections of root meristem cells of Allium cepa and a human tumor cell line (TG cells). In vegetal cells, after 5 min of staining reaction, the Ag-NOR proteins formed ring-shaped structures peripherally within the nucleolus. In animal cells silver granules were distributed over the entire nucleolus. The specificity of the staining reaction was increased by incubation of the sections in NH4Cl and Schiff's reagent prior to Ag-NOR silver staining.     

Silver staining of the nucleolar organizer regions (NORs) on Lowicryl and cryo-ultrathin sections

Nucleolar organizer region (NOR) silver staining was applied to sections of fixed material. A positive reaction on cryo-ultrathin sections was found as well as on semithin and ultrathin Lowicryl sections. Repeatable staining that was easy to control was obtained by a one-step procedure after aldehyde-Carnoy fixation. Fixation of the material by formaldehyde and glutaraldehyde alone in cacodylate buffer also maintained reaction selectivity when ammonium chloride was used after fixation. Enzymatic digestion by pronase, RNase A, DNase I, or micrococcal nuclease was applied to ultrathin Lowicryl sections. Pronase digestion removed the silver-stained proteins, whereas digestion by the nucleases did not. A routine procedure is proposed for easy NOR silver staining of sections that preserves a good tissue ultrastructure and is also compatible with cytochemical and immunological investigations.     

Morphometric variation in nearly unstudied populations of the most studied mammal: The non-commensal house mouse (Mus musculus domesticus) in the Near East and Northern Africa

The phenotypic consequences in the house mouse (Mus musculus domesticus) of the transition from an ordinary field-dwelling rodent to a species that is dependent on human populations was studied by investigating the morphometric variation of non-commensal populations of M. m. domesticus from Syria, Jordan, SW Iran, and Libya and comparing them with that of conspecific commensal populations from Eastern Turkey, Greece, and Bulgaria. Commensal populations of M. musculus musculus from the Czech Republic were used as an outgroup. About 849 adult specimens of M. musculus were analysed by multivariate procedures based on standard molar, skull and body measurements. As expected, there was considerable variation among the studied populations and a good correspondence between morphometric and geographic distances. The resulting morphometric tree was consistent with the hypothesis that the original radiation of M. m. domesticus took place somewhere in the Near East. Commensal populations of M. m. domesticus form a single derived branch. Specimens originating from four different sites in eastern Syria showed the greatest similarity to one another and possessed relatively bigger molars than the other studied populations. Commensal populations were characterised by longer tails when compared to non-commensal populations, which suggests an adaptation for living in a more three-dimensionally heterogeneous environment for commensal populations.     

Loss of nucleolar organizer regions during chromosomal evolution in the South American cricetid Graomys griseoflavus

Graomys griseoflavus is a South American phyllotine rodent having a remarkable Robertsonian polymorphism which may have produced reproductive isolation between 2n=42–41 and 2n=38–34 karyomorphs. Analysis of nucleolar organizer region (NOR) locations both by silver staining (Ag-NOR) and in situ hybridization revealed that 2n=42 individuals exhibit highly variable Ag-NOR patterns, while specimens of the 2n=38–34 karyomorphic group showed a single Ag-NOR pattern. The latter animals underwent two NOR deletions in reference to the 2n=42 karyomorphs, one of which would be the consequence of a Robertsonian fusion and the other would be produced by the unequal crossing-over mechanism. The differential NOR homogenization supports the hypothesis that G. griseoflavus karyomorphs are evolving separately towards the acquisition of separate species status.     

Speciation slowing down in widespread and long-living tree taxa: insights from the tropical timber tree genus Milicia (Moraceae)

The long generation time and large effective size of widespread forest tree species can result in slow evolutionary rate and incomplete lineage sorting, complicating species delimitation. We addressed this issue with the African timber tree genus Milicia that comprises two morphologically similar and often confounded species: M. excelsa, widespread from West to East Africa, and M. regia, endemic to West Africa. We combined information from nuclear microsatellites (nSSRs), nuclear and plastid DNA sequences, and morphological systematics to identify significant evolutionary units and infer their evolutionary and biogeographical history. We detected five geographically coherent genetic clusters using nSSRs and three levels of genetic differentiation. First, one West African cluster matched perfectly with the morphospecies M. regia that formed a monophyletic clade at both DNA sequences. Second, a West African M. excelsa cluster formed a monophyletic group at plastid DNA and was more related to M. regia than to Central African M. excelsa, but shared many haplotypes with the latter at nuclear DNA. Third, three Central African clusters appeared little differentiated and shared most of their haplotypes. Although gene tree paraphyly could suggest a single species in Milicia following the phylogenetic species concept, the existence of mutual haplotypic exclusivity and nonadmixed genetic clusters in the contact area of the two taxa indicate strong reproductive isolation and, thus, two species following the biological species concept. Molecular dating of the first divergence events showed that speciation in Milicia is ancient (Tertiary), indicating that long-living tree taxa exhibiting genetic speciation may remain similar morphologically.     

Nucleolar organizer regions (NORs) distribution and behavior in spermatozoa and meiotic cells of the horse (Equus caballus)

Nucleolar organizing regions (NORs) containing rDNA gene clusters have been assigned to the equine autosomes ECA1, ECA28, and ECA31. Active NORs (Ag-NORs) are associated with argyrophilic proteins, which allow them to be readily identified using silver staining techniques. Fluorescence in situ hybridization (FISH) for rDNA can also be used to visualize all NOR clusters in the nucleus, regardless of whether they are active or inactive. The present study analyzed the distribution and behavior of equine Ag-NOR and NOR clusters in horse spermatozoa and during male meiosis by FISH and silver staining. The NOR foci were observed to be variable in number, size, and shape, but were usually located centrally and appeared as one or two nucleolus-like structures in the spermatozoa head. Three distinctive FISH signals identified the NOR-bearing chromosome pairs during the synaptic cell stage of meiosis I. At diakinesis/metaphase I, as well as different stages of meiosis II, FISH signals clearly depicted the NOR-bearing sister chromatids. The synaptonemal complexes of primary spermatocytes consistently showed three rDNA foci following FISH, but variably demonstrated two or three Ag-NOR bodies following silver staining. We propose rDNA loss and gain during unequal crossing-over events could be both a direct and indirect cause of variation in equine NOR foci. Additionally, our cytogenetic analysis did not confirm the presence of a fourth pair of NORs-bearing chromosomes in the horse, which is contrary to previously mitotic published data.     

Linkage of the locus for conversion of albumin (Acf-1)in the house mouse,Mus musculus

The linkage of the locus for conversion of albumin (Acf-1) has been established on chromosome 1 with the following gene order and recombination percentages: Id-1 19.3±5.2% Acf-1 4.2±1.7% Dip-1 18.4±4.2% Lp.This work was supported by NIH Postdoctoral Fellowship 1F32 GM0527701, Grant BMS75-03397 from the National Science Foundation, Grant ACS VC-17-R from the American Cancer Society, and Contract NO1-ES42159 from the National Institute of Environmental Health Sciences. The Jackson Laboratory is fully accredited by the American Association for the Accreditation of Laboratory Animal Care.     

Chromosomal location of soluble glutamic-pyruvic transaminase-1 (Gpt-1) in the mouse

Three alleles at the Gpt-1 (glutamic-pyruvic transaminase-1) locus in the mouse, as identified by electrophoresis on cellulose acetate, and their distribution among inbred mouse strains and wild stocks are described. The Gpt-1 locus was shown to control the soluble form of the enzyme. Three-point linkage analysis established the location of Gpt-1 on chromosome 15 between uw and bt. In addition, a new staining procedure is described that allows the visualization of GPT activity on gels by the deposition of formazan. This is an improvement over previous methods that produced bands of nonfluorescence against a fluorescent background.This investigation was supported in part by Research Grant GM 20919 from the National Institute of General Medical Sciences, and by contract NO1-ES-4-2159 with the National Institute of Environmental Health Sciences. The Jackson Laboratory is fully accredited by the American Association for Accreditation of Laboratory Animal Care.     

Butlerius butleri Goodey, 1929 (Rhabditida) from Iran with the Phylogenetic Position of the Species

A population of Butlerius butleri Goodey, 1929 was isolated from vermicompost in Kerman in the Kerman Province of Iran during a nematode survey that was conducted during 2014. This population of B. butleri is characterized by the presence of a dorsal thorn-like tooth (4 to 5 μm long), long spicules (44 to 47 μm long), gubernaculum (33 to 37 μm or more than half of the spicule length), three pairs of precloacal papillae, five pairs of postcloacal papillae (papillae V3 and V5 comprising three small papillae), and a long filiform tail (304 to 409 μm in females, 312 to 380 μm in males). Molecular and phylogenetic analysis of B. butleri individuals from this Iranian population based on 18S ribosomal deoxyribonucleic acid (rDNA) sequence placed this species close to Pseudodiplogasteroides compositus ({"type":"entrez-nucleotide","attrs":{"text":"AB597237","term_id":"354681824","term_text":"AB597237"}}AB597237) and an unidentified Pseudodiplogasteroides species ({"type":"entrez-nucleotide","attrs":{"text":"AB597238","term_id":"354681825","term_text":"AB597238"}}AB597238). Measurements, illustrations, and the phylogenetic tree, including the position of B. butleri are provided.     

The diverse origins of New Zealand house mice

Molecular markers and morphological characters can help infer the colonization history of organisms. A combination of mitochondrial (mt) D-loop DNA sequences, nuclear DNA data, external measurements and skull characteristics shows that house mice (Mus musculus) in New Zealand and its outlying islands are descended from very diverse sources. The predominant genome is Mus musculus domesticus (from western Europe), but Mus musculus musculus (from central Europe) and Mus musculus castaneus (from southern Asia) are also represented genetically. These subspecies have hybridized to produce combinations of musculus and domesticus nuclear DNA coupled with domesticus mtDNA, and castaneus or musculus mtDNA with domesticus nuclear DNA. The majority of the mice with domesticus mtDNA that we sampled had D-loop sequences identical to two haplotypes common in Britain. This is consistent with long-term British-New Zealand cultural linkages. The origins of the castaneus mtDNA sequences widespread in New Zealand are less easy to identify.     

Xenopsylla spp. (Siphonaptera: Pulicidae) in murid rodents from the Canary Islands: An update

The geographical and host distributions of Xenopsylla fleas parasitizing murid rodents on the Canary Islands have been reported. Three Xenopsylla species, X. cheopis, X. brasiliensis and X. guancha, have been detected on two rodents species, Mus musculus and Rattus rattus. X. guancha has been the most prevalent species detected, specifically on M. musculus, the most abundant rodent, but it has been detected only on three eastern islands, where the species is endemic. X. cheopis has been shown to be the most widely distributed species throughout the archipelago and the species most frequently found on R. rattus. X. brasiliensis has been shown to be the least prevalent Xenopsylla species, with the lowest geographical distribution on the Canary Islands and focused only on R. rattus. The detection of both X. cheopis and X. brasiliensis on the island of Lanzarote, and of X. guancha on the island of Fuerteventura and the islet of La Graciosa represents the first report of these species on those particular Canary Islands.     

Genetics of alkaline phosphatase of the small intestine of the house mouse (Mus musculus)

Four inbred strains of mice exhibited either slow (PL/J), intermediate (DBA/2J, LP/J), or fast (SWR/J) rates of migration of duodenal alkaline phosphatase on cellulose acetate electrophoresis. Hybrids of these strains also had intermediate rates of migration regardless of the combination of strains used as parents. Strain differences were present in all regions of the small but not the large intestine. Crosses of the PL/J strain to hybrids between this strain and the other three strains gave a 1:1 segregation of the slow and intermediate patterns. The symbol Akp-3 is proposed for the locus responsible for the slower migration of the enzyme in this strain. Data from the LP/J × PL/J hybrid crossed with the PL/J strain showed linkage with two loci on chromosome 1 as follows: centromere—Idh-1–13.8±3.1 cM—Akp-3–8.9±2.6 cM—Pep-3. The available data do not reveal the genetic basis for the faster migration rate of the enzyme from the SWR/J strain, but a different response to neuraminidase and apparent nonlinkage to the Pep-3 locus suggest that a locus other than Akp-3 is responsible.This work was supported by a grant from the University Research Committee, Indiana State University.     

East asian hemoglobin type (Hbb p) in wild populations of the house mouse in Israel

Electrophoretic studies of hundreds of individuals showed that all wild populations of the house mouse in Israel are polymorphic for alleles Hbb ^d and Hbb ^p of the hemoglobin locus. No mouse carrying Hbb ^s was found. This finding contradicts the notion that Hbb ^p is limited to East Asian house mice.     

The phylogenetic affinities of Crossley's babbler (Mystacornis crossleyi): adding a new niche to the vanga radiation of Madagascar

Crossley's babbler (Mystacornis crossleyi) is a passerine endemic to Madagascar. Traditionally, it has been classified as a babbler (Timaliidae), although affinities with warblers and vangas have been suggested. We investigated the phylogenetic affinities of Crossley's babbler using sequence data from two nuclear introns (myoglobin intron 2 and beta-fibrinogen intron 5) and one mitochondrial gene (ND2). We present for the first time (to our knowledge) a molecular phylogeny that confidently places this enigmatic species within the vangas (Vangidae). The inclusion of Crossley's babbler within the vangas adds another foraging niche--gleaning small invertebrates from the ground-to this already large adaptive radiation of songbirds.