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.     

Oestrous females investigate the unfamiliar male more than the familiar male in both commensal and non-commensal populations of house mice

We studied female preferences for familiar and unfamiliar males. The subjects were laboratory-born house mice: (1) non-commensal Mus musculus domesticus from the eastern part of Syria along the Euphrates River; and (2) commensal M. m. musculus from the Czech Republic. Pair-choice preference tests have revealed that oestrous females of both populations sniffed towards unfamiliar males more than familiar males. In the case of females exhibiting postpartum oestrus, this preference was less pronounced and statistically not significant. Thus, our mice clearly exhibited the behavioural pattern known from commensal populations of polygynous and/or promiscuous M. m. domesticus. We found no inverse tendency to seek proximity to the familiar male that has been previously reported from closely related and presumably monogamous aboriginal mouse Mus spicilegus. We conclude that neither commensal M. m. musculus, nor non-commensal M. m. domesticus, are likely to share a monogamous mating system with mound-building mice.     

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.     

复合不育剂EP-1对小鼠空间记忆与焦虑行为的影响

EP-1是由炔雌醚和左炔诺孕酮按照1∶2的比例配制而成的一种用于鼠类不育控制的激素类复合不育剂,对鼠类的繁殖及繁殖行为等有一定影响,但对鼠类空间学习与记忆、焦虑行为等非繁殖行为的影响还没有报道。为此,用0(对照)、1.0、2.0、3.0 mg/kg剂量的EP-1对昆明小鼠(Mus musculus)进行灌胃处理,然后用Morris水迷宫和高架十字迷宫分别测定其空间记忆、焦虑行为。结果发现灌胃后15 d,剂量为2.0 mg/kg的EP-1使小鼠空间记忆能力显著下降,但30 d后其空间记忆能力有所恢复,表明2.0 mg/kg剂量的EP-1可以在一定时间范围内降低小鼠的空间记忆能力。但不同剂量的EP-1对小鼠焦虑行为无显著影响。该结果可以为从对非繁殖行为的影响的角度研究EP-1对鼠类的作用提供一定启示。     

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.     

Seasonal variation in the metabolism-temperature relation of House Sparrows (Passer domesticus) in KwaZulu-Natal,South Africa

Many birds exhibit considerable phenotypic flexibility in metabolism to maintain thermoregulation or to conserve energy. This flexibility usually includes seasonal variation in metabolic rate. Seasonal changes in physiology and behavior of birds are considered to be a part of their adaptive strategy for survival and reproductive success. House Sparrows (Passer domesticus) are small passerines from Europe that have been successfully introduced to many parts of the world, and thus may be expected to exhibit high phenotypic flexibility in metabolic rate. Mass specific Resting Metabolic Rate (RMR) and Basal Metabolic Rate (BMR) were significantly higher in winter compared with summer, although there was no significant difference between body mass in summer and winter. A similar, narrow thermal neutral zone (25–28 °C) was observed in both seasons. Winter elevation of metabolic rate in House Sparrows was presumably related to metabolic or morphological adjustments to meet the extra energy demands of cold winters. Overall, House Sparrows showed seasonal metabolic acclimatization similar to other temperate wintering passerines. The improved cold tolerance was associated with a significant increase in VO₂ in winter relative to summer. In addition, some summer birds died at 5 °C, whereas winter birds did not, further showing seasonal variation in cold tolerance. The increase in BMR of 120% in winter, compared to summer, is by far the highest recorded seasonal change so far in birds.     

Genetic variation for prolidase (PEP-4) in the mouse maps near the gene for glucosephosphate isomerase (GPI-1) on chromosome 7

An inherited electrophoretic variant of prolidase (EC 3.4.13.9), also called peptidase 4 (PEP-4), has been discovered among inbred strains of mice. Analysis of progeny from reciprocal backcrosses established that the electrophoretic forms are expressed codominantly and that Pep-4 is located between the genes for glucosephosphate isomerase (Gpi-1) and pink-eyed dilution (p) on chromosome 7. These data define a region of conserved gene linkage between mouse chromosome 7 and human chromosome 19, as originally indicated by somatic cell hybrid studies, and imply that human prolidase (PEPD) is located in the region of human chromosome 19 pter q13.Research sponsored by the Office of Health and Environmental Research, U.S. Department of Energy, under Contract W-7405-eng-26 with the Union Carbide Corporation.By acceptance of this article, the publisher or recipient acknowledges the right of the U.S. Government to retain a nonexclusive, royalty-free license in and to any copyright covering the article.     

Chromosomal dynamics of nucleolar organizer regions (NORs) in the house mouse: micro-evolutionary insights

Variation in the number and chromosomal location of nucleolar organizer regions (NORs) was studied in the house mouse, Mus musculus (2n=40). From an origin in Western Asia, this species colonized the Middle East, Europe and Asia. This expansion was accompanied by diversification into five subspecies. NOR diversity was revealed by fluorescence in situ hybridization using 18S and 28S probes on specimens spanning Asia to Western Europe. The results showed that the house mouse genome possessed a large number of NOR-bearing autosomes and a surprisingly high rate of polymorphism for the presence/absence of rRNA genes on all these chromosomes. All NOR sites were adjacent to the centromere except for two that were telomeric. Subspecific differentiation established from the NOR frequency data was concordant with the overall pattern of radiation proposed from molecular studies, but highlighted several discrepancies that need to be further addressed. NOR diversity in M. musculus consisted of a large number of polymorphic NORs that were common to at least two subspecies, and a smaller number of NORs that were unique to one subspecies. The most parsimonious scenario argues in favor of a subspecific differentiation by lineage sorting of ancestral NOR polymorphisms; only the unique NORs would have appeared by inter-chromosomal transposition, except for the two telomeric ones that may have originated by hybridization with another species. Such a scenario provides an alternative view from the one prevailing in most systematic and phylogenetic analyses that NORs have a high transposition rate due to concerted evolution of rRNA genes.     

Frequency and distribution of t-haplotypes in the Southeast Asian house mouse (Mus musculus castaneus) in Taiwan

t-haplotypes are a meiotic drive system found on the 17th chromosome of the house mouse (Mus musculus). They can be found in wild populations of all four genetically differentiated subspecies. The drive phenomenon is male-specific, such that heterozygous males (+/t) show non-Mendelian transmission and transmit the t-chromosome to > 90% of their offspring. So far the most comprehensive studies on the frequencies of t-haplotypes in natural populations have been on just one of the subspecies (M. musculus domesticus). We applied molecular methods to accurately screen t-haplotypes in a large number of populations of a second subspecies (M. musculus castaneus) distributed in Taiwan. We found that the overall t-haplotype frequency is low in M. m. castaneus (0.108), and the chromosomes are patchily distributed among its populations, closely resembling the situation found in M. m. domesticus. Further, we found the frequencies of t-haplotypes in our sample did not differ in relation to the sex or age of mice. This resemblance in the frequency and distribution among populations of the two distinct subspecies suggests that similar general mechanisms might be responsible for the low frequencies in both subspecies.     

Chloroplast microsatellite diversity of Clintonia udensis (Liliaceae) populations in East Asia

Nineteen populations of Clintonia udensis Trautv. & Mey. were examined to quantify genetic diversity and genetic structure by chloroplast DNA microsatellites (cpSSR). Significant cpSSR genetic diversity (PPB = 63.64%) was detected in this species. Tetraploid populations demonstrated approximately the same level of genetic diversity as the diploid ones. A significant differentiation, however, was found between tetraploids and diploids. Most of the sixteen chloroplast haplotypes were limited to a single population. The level of haplotype diversity was high (Hd = 0.915). AMOVA, PCA and Bayesian clustering analysis revealed that there were significant genetic differences among populations. Inter-population genetic distances among population sites correlated significantly with geographic distances. These results indicate that the mixed-mating – breeding system, limited gene flow, environmental stress, and historical factors may be the main factors causing geographical differentiation in the genetic structure of C. udensis.     

Geographic phenetic variation of two eastern-Mediterranean non-commensal mouse species, Mus macedonicus and M. cypriacus (Rodentia: Muridae) based on traditional and geometric approaches to morphometrics

We tested the hypothesis that skull shape within the genus Mus may vary with geographic location by assessing the extent and spatial distribution of phenotypic skull variation within and among two wild mouse species, M. macedonicus and M. cypriacus, using traditional and geometric morphometrics including a rather novel application of sliding semilandmarks. Shape was shown to be significantly correlated both with longitude and latitude in M. macedonicus, yet the correlation between morphometric and geographic distances was not significant, and morphometric differences between Asian and European populations were not higher than those within the particular continents. The phylogenetic signal was found to be stronger in dental characters than in cranial ones, however, overall concordance between the pattern of morphometric variation and the presumed history of M. macedonicus was rather weak. In both species, the dorsal and ventral sides of the skull were shown to covary in many aspects though there were also some differences between them, making the functional interpretation of these differences difficult. Discrimination between M. cypriacus and M. macedonicus as well as discrimination between two M. macedonicus subspecies was highly reliable using both traditional and geometric morphometric tools to analyze skull measurements.     

Genetic variation in populations of the threatened seagrass Halophila beccarii (Hydrocharitaceae)

Halophila beccarii (Hydrocharitaceae), a small monoecious seagrass, has been listed as a threatened species. In this study, a total of 106 samples were collected from four Chinese populations located at the northern limit of its distribution range. Using six polymorphic microsatellites, we found low genetic variation in this species, in which the mean number of alleles per locus was 2.8, and 16 multi-locus genotypes were revealed. In the four populations, the mean number of alleles per locus ranged from 1.2 to 2, one to eight genotypes were found, and clonal diversity ranged from 0 to 0.23; observed and expected heterozygosity ranged from 0.17 to 0.40 and from 0.09 to 0.24, respectively. Strong genetic differentiation was found among the populations, and the standardized fixation index (F′_ST) was 0.787. Species traits (i.e., clonal growth) and bottleneck effects due to drastic population fluctuation may contribute to the observed low genetic variation.     

Spatio-temporal variation in the structure of a chromosomal polymorphism zone in the house mouse

Several long-term temporal analyses of the structure of Robertsonian (Rb) hybrid zones in the western house mouse, Mus musculus domesticus, have been performed. Nevertheless, the detection of gradual or very rapid variations in a zone may be overlooked when the time elapsed between periods of study is too long. The Barcelona chromosomal polymorphism zone of the house mouse covers about 5000, km(2) around the city of Barcelona and is surrounded by 40 chromosome telocentric populations. Seven different metacentrics and mice with diploid numbers between 27 and 40 chromosomes and several fusions in heterozygous state (from one to seven) have been reported. We compare the present (period 2008-2010) and past (period 1996-2000) structure of this zone before examining its dynamics in more detail. Results indicate that there is not a Rb race in this area, which is consistent with the proposal that this zone was probably originated in situ, under a primary intergradation scenario. The lack of individuals with more than five metacentrics in heterozygous state in the current period suggests that selection acted against such mice. By contrast, this situation did not occur for mice with fewer than five fusions in heterozygous condition. Changes in human activity may affect the dynamics of gene flow between subpopulations, thus altering the chromosomal composition of certain sites. Although these local variations may have modified the clinal trend for certain metacentrics, the general staggered structure of the zone has not varied significantly in a decade.     

The telocentric tandem repeat at the p-arm is not conserved in Mus musculus subspecies

Mouse chromosomes, with the exception of the Y chromosome, are telocentric. The telomere at the p-arm is separated from the centromere by the tL1 sequence and TLC tandem repeats. A previous report showed that the TLC array was also conserved in other strains of the subgenus Mus. These results suggest that the TLC arrays promote the stable evolutionary maintenance of a telocentric karyotype in the subgenus Mus. In this study, we investigated the degree of conservation of TLC arrays among a variety of wild-derived inbred strains, all of which are descendants of wild mice captured in several areas of the world. Genomic PCR analysis indicates that the sequential order of telomere-tL1 is highly conserved in all strains, whereas tL1-TLC is not. Next, Southern blot analysis of DNAs isolated from a panel of mouse subspecies showed both Mus musculus domesticus and Mus musculus castaneus subspecies possess TLC arrays. Unexpectedly, this repeat appears to be lost in almost all Mus musculus musculus and Mus musculus molossinus subspecies, which show a clear geographic divide. These results indicate that either other unknown sequences were replaced by the TLC repeat or almost all M. m. musculus and M. m. molossinus subspecies do not have any sequence between the telomere and minor satellites. Our observation suggests that the TLC array might be evolutionarily unstable and not essential for murine chromosomal conformation. This is the first example of the subspecies-specific large genome alterations in mice.     

Genetic structure of Phlebotomus (Larroussius) ariasi populations, the vector of Leishmania infantum in the western Mediterranean: Epidemiological implications

In recent years there has been growing interest in analyzing the geographical variations between populations of different Phlebotomus spp. by comparing the sequences of various genes. However, little is known about the genetic structure of Phlebotomus ariasi. In this study, we were able to sequence a fragment of the mitochondrial Cyt b gene in 133 sandflies morphologically identified as P. ariasi and proceeding from a wide geographical range covering 35 locations in 11 different regions from five countries. The intra-specific diversity of P. ariasi is high, with 45 haplotypes differing from each other by one to 26 bases and they are distributed in two mitochondrial lineages, one limited geographically to Algeria and the other widely dispersed across Mediterranean countries. The Algerian lineage is characterized by having 13 fixed polymorphisms and is made up of one sole haplotype. The European/Moroccan P. ariasi lineage is characterized by being made up of a great diversity of haplotypes (44) which display some geographical structuring. This could be one of the multiple factors involved in the epidemiological heterogeneity of the foci of leishmaniasis. Phlebotomus chadlii is the sister group of European/Moroccan P. ariasi. The separation of the Algerian haplotype, H45, from the rest of the specimens, European/Moroccan P. ariasi and P. chadlii, is well supported by the bootstrap analysis.     

Genetic structure of house mouse (Mus musculus Linnaeus 1758) populations in the Atlantic archipelago of the Azores: colonization and dispersal

We analyzed the genetic structure and relationships of house mouse (Mus musculus) populations in the remote Atlantic archipelago of the Azores using nuclear sequences and microsatellites. We typed Btk and Zfy2 to confirm that the subspecies Mus musculus domesticus was the predominant genome in the archipelago. Nineteen microsatellite loci (one per autosome) were typed in a total of 380 individuals from all nine Azorean islands, the neighbouring Madeiran archipelago (Madeira and Porto Santo islands), and mainland Portugal. Levels of heterozygosity were high on the islands, arguing against population bottlenecking. The Azorean house mouse populations were differentiated from the Portuguese and Madeiran populations and no evidence of recent migration between the three was obtained. Within the Azores, the Eastern, Western, and Central island groups tended to act as separate genetic units for house mice, with some exceptions. In particular, there was evidence of recent migration events among islands of the Central island group, whose populations were relatively undifferentiated. Santa Maria had genetically distinctive mice, which may relate to its colonization history. © 2013 The Linnean Society of London     

Serotonin has kinin-like activity in stimulating secretion by Malpighian tubules of the house cricket Acheta domesticus

Serotonin stimulates secretion by Malpighian tubules (MT) of a number of insects, and functions as a diuretic hormone in Rhodnius prolixus and in larval Aedes aegypti. Serotonin is here shown to be a potent stimulant of secretion by MT of the house cricket, Acheta domesticus, with an apparent EC₅₀ of 9.4 nmol L⁻¹, although its diuretic activity is just 25% of the maximum achievable with either the native CRF-related peptide, Achdo-DH, or a crude extract of the corpora cardiaca. In this respect, the diuretic activity of serotonin is similar to that of the cricket kinin Achdo-KI, and when tested together their actions are not additive, which suggests they target the same transport process. Consistent with this suggestion, the activity of serotonin is chloride-dependent and is associated with a non-selective stimulation of NaCl and KCl transport. In common with Achdo-KI, serotonin has no effect on cAMP production by isolated MT, and both act synergistically with exogenous 8bromo-cAMP in stimulating fluid secretion, most likely by promoting the release of Ca²⁺ from intracellular stores. A number of serotonin agonists and antagonists were tested to determine the pharmacological profile of receptors on cricket MT. The results are consistent with the diuretic activity of serotonin being mediated through a 5-HT₂-like receptor.     

Morphological variation and relationships of Georgian populations of Vitis vinifera L. subsp. sylvestris (C.C. Gmel.) Hegi

Georgia is considered as one of the regions where for the first time wild growing grapevine plants were used and taken into cultivation by men. An ampelographic and ampelometric study of leaf characters and flower landmark morphometrics was carried out in seven populations of wild grapevine located in four river basins of three geographic regions – Western (1 popul.), Eastern (5 popul.) and Southern (1 popul.) Georgia, and then compared using principal component analysis and multivariate discriminant analysis allowing the populations to be distinguished. Lengths of main leaf veins and nectaries in male flowers were the variables, which allowed the best discrimination among populations. A mutation leading to white-fruited grapevine is found in one population. Pubescence varies within populations and even within an individual genome and could be used as a discriminant trait only in combination with shapes and sizes of leaves and other morphological characters. The results revealed significant differences among populations located in different geographic regions of the Southern Caucasus area, but the five investigated populations from Eastern Georgia differ only insignificantly. The high morphological variability of wild grapevine in Georgia might be considered as characterizing the large gene pool that contributed to the domestication process of grapevine.     

The identification of microRNAs in the whitespotted bamboo shark (Chiloscyllium plagiosum) liver by Illumina sequencing

MicroRNAs are indispensable players in the regulation of a broad range of biological processes. Here, we report the first deep sequencing of the whitespotted bamboo shark (Chiloscyllium plagiosum) liver. We mapped 91 miRNAs in the Callorhinchus milii genome that have previously been described in the Danio rerio, Fugu rubripes, Oryzias latipes, Xenopus laevis, Xenopus tropicalis, Homo sapiens, and Mus musculus. In addition, 156 new putative candidate (PC) C. plagiosum miRNAs were identified. From these 247 miRNAs, 39 miRNA clusters were identified, and the expression of these clustered miRNAs was observed to vary significantly. A total of 7 candidate miRNAs were selected for expression confirmation by stem-loop RT-PCR. This study resulted in the addition of a significant number of novel miRNA sequences to GenBank and laid the foundation for further understanding of the function of miRNAs in the regulation of C. plagiosum liver development.