The Prevalence of <Emphasis Type="Italic">Trypanosoma cruzi</Emphasis>, the Causal Agent of Chagas Disease,in Texas Rodent Populations

Rodent species were assessed as potential hosts of Trypanosoma cruzi, the etiologic agent of Chagas disease, from five sites throughout Texas in sylvan and disturbed habitats. A total of 592 rodents were captured, resulting in a wide taxonomic representation of 11 genera and 15 species. Heart samples of 543 individuals were successfully analyzed by SybrGreen-based quantitative PCR (qPCR) targeting a 166 bp fragment of satellite DNA of T. cruzi. Eight rodents representing six species from six genera and two families were infected with T. cruzi. This is the first report of T. cruzi in the pygmy mouse (Baiomys taylori) and the white-footed mouse (Peromyscus leucopus) for the USA. All infected rodents were from the southernmost site (Las Palomas Wildlife Management Area). No differences in pathogen prevalence existed between disturbed habitats (5 of 131 tested; 3.8%) and sylvan habitats (3 of 40 tested; 7.5%). Most positives (n = 6, 16% prevalence) were detected in late winter with single positives in both spring (3% prevalence) and fall (1% prevalence). Additionally, 30 Triatoma insects were collected opportunistically from sites in central Texas. Fifty percent of these insects, i.e., 13 T. gerstaeckeri (68%), and two T. lecticularia (100%) were positive for T. cruzi. Comparative sequence analyses of 18S rRNA of samples provided identical results with respect to detection of the presence or absence of T. cruzi and assigned T. cruzi from rodents collected in late winter to lineage TcI. T. cruzi from Triatoma sp. and rodents from subsequent collections in spring and fall were different, however, and could not be assigned to other lineages with certainty.     

A decrease in heat insulation of the black-clawed brush-furred rat (<Emphasis Type="Italic">Lophuromys melanonyx</Emphasis>, Petter) during adaptation to high altitudes

The results of the body-surface infrared thermography of rodents of the genus Lophuromys suggest that heat insulation of the black-clawed brush-furred rat L. melanonyx, a large specialized species of the AfroAlpine zone, is worse than that of the related smaller species, the golden-footed (L. chrysopus) and shorttailed (L. brevicaudus) brush-furred rats, that inhabit tropical forest and Erica shrub, respectively. A decrease in heat insulation of the alpine species may facilitate the use of solar radiation for supporting heat balance of these diurnal animals.     

<Emphasis Type="Italic">CER1</Emphasis>gene variations associated with bone mineral density,bone markers,and early menopause in postmenopausal women

Background

Osteoporosis has a multifactorial pathogenesis characterized by a combination of low bone mass and increased fragility. In our study, we focused on the effects of polymorphisms in CER1 and DKK1 genes, recently reported as important susceptibility genes for osteoporosis, on bone mineral density (BMD) and bone markers in osteoporotic women. Our objective was to evaluate the effect of CER1 and DKK1 variations in 607 postmenopausal women. The entire DKK1 gene sequence and five selected CER1 SNPs were amplified and resequenced to assess whether there is a correlation between these genes and BMD, early menopause, and bone turnover markers in osteoporotic patients.

Results

Osteoporotic women seem to suffer menopause 2 years earlier than the control group. The entire DKK1 gene sequence analysis revealed six variations. There was no correlation between the six DKK1 variations and osteoporosis, in contrast to the five common CER1 variations that were significantly associated with BMD. Additionally, osteoporotic patients with rs3747532 and rs7022304 CER1 variations had significantly higher serum levels of parathyroid hormone and calcitonin and lower serum levels of osteocalcin and IGF-1.

Conclusions

No significant association between the studied DKK1 variations and osteoporosis was found, while CER1 variations seem to play a significant role in the determination of osteoporosis and a potential predictive role, combined with bone markers, in postmenopausal osteoporotic women.

     

Loss of the nutrient sensor TAS1R3 leads to reduced bone resorption

The taste receptor type 1 (TAS1R) family of heterotrimeric G protein-coupled receptors participates in monitoring energy and nutrient status. TAS1R member 3 (TAS1R3) is a bi-functional protein that recognizes amino acids such as L-glycine and L-glutamate or sweet molecules such as sucrose and fructose when dimerized with TAS1R member 1 (TAS1R1) or TAS1R member 2 (TAS1R2), respectively. It was recently reported that deletion of TAS1R3 expression in Tas1R3 mutant mice leads to increased cortical bone mass but the underlying cellular mechanism leading to this phenotype remains unclear. Here, we independently corroborate the increased thickness of cortical bone in femurs of 20-week-old male Tas1R3 mutant mice and confirm that Tas1R3 is expressed in the bone environment. Tas1R3 is expressed in undifferentiated bone marrow stromal cells (BMSCs) in vitro and its expression is maintained during BMP2-induced osteogenic differentiation. However, levels of the bone formation marker procollagen type I N-terminal propeptide (PINP) are unchanged in the serum of 20-week-old Tas1R3 mutant mice as compared to controls. In contrast, levels of the bone resorption marker collagen type I C-telopeptide are reduced greater than 60% in Tas1R3 mutant mice. Consistent with this, Tas1R3 and its putative signaling partner Tas1R2 are expressed in primary osteoclasts and their expression levels positively correlate with differentiation status. Collectively, these findings suggest that high bone mass in Tas1R3 mutant mice is due to uncoupled bone remodeling with reduced osteoclast function and provide rationale for future experiments examining the cell-type-dependent role for TAS1R family members in nutrient sensing in postnatal bone remodeling.     

CSF3R,SETBP1 and CALR mutations in chronic neutrophilic leukemia

The WHO 2008 definition of chronic neutrophilic leukemia (CNL) is based on clinical and laboratory parameters but not on molecular abnormalities. Mutations in CSF3R, SETBP1 and CALR are reported in patients with chronic neutrophilic leukemia (CNL). However, because CNL is rare, there are few large studies of this issue. We sequenced these genes in 14 patients who met the WHO-criteria of CNL. 8 subjects had CSF3R ^T618I , 6 SETBP1 mutations and 1 a CALR mutation. Our data suggest mutation analysis of CSF3R, SETBP1 and CALR should be included in the diagnostic criteria for CNL. These data may also have therapy implications.     

Expression of osteogenesis regulatory genes in the bone tissue of patients with acromegaly and endogenous hypercorticism

Excessive hormone secretion during hypercorticism and acromegaly results in significant disturbances in bone remodeling, decrease in bone quality, and bone fractures following small traumas. However, the mechanisms of the development of such changes are not clear. In the present study, we examined specimens of bone tissue from patients with endogenous hypercorticism (increased cortisol secretion) and acromegaly (increased growth hormone secretion) obtained during transnasal adenomectomy. Our main purpose was to analyze the expression of genes responsible for osteogenesis in the bone tissue specimens from patients with hypercorticism and acromegaly, targeting an assessment of pathogenetic aspects associated with bone complications. The study included 19 specimens of bone tissue from patients with pituitary tumors (samples with acromegaly, Cushing disease, and inactive pituitary adenomas; the latter served as a control group). We revealed 14 genes (ACP5, ALPL, BGLAP, BMP7, CD40, COL1A1, COL1A2, IGF1, IGFBP2, IL6, LEP, LTA, MMP2, WNT10B) which appeared to be the most important and require further detailed study. The present study confirmed the key role of the Wnt-signaling pathway in the osteogenic process. In addition, we present new data on molecular mechanisms of development of skeletal complications in the case of cortisol and growth hormone oversecretion in humans.     

Gene up-regulation in response to predator kairomones in the water flea, <Emphasis Type="Italic">Daphnia pulex</Emphasis>

Background

Numerous cases of predator-induced polyphenisms, in which alternate phenotypes are produced in response to extrinsic stimuli, have been reported in aquatic taxa to date. The genus Daphnia (Branchiopoda, Cladocera) provides a model experimental system for the study of the developmental mechanisms and evolutionary processes associated with predator-induced polyphenisms. In D. pulex, juveniles form neckteeth in response to predatory kairomones released by Chaoborus larvae (Insecta, Diptera).

Results

Previous studies suggest that the timing of the sensitivity to kairomones in D. pulex can generally be divided into the embryonic and postembryonic developmental periods. We therefore examined which of the genes in the embryonic and first-instar juvenile stages exhibit different expression levels in the presence or absence of predator kairomones. Employing a candidate gene approach and identifying differentially-expressed genes revealed that the morphogenetic factors, Hox3, extradenticle and escargot, were up-regulated by kairomones in the postembryonic stage and may potentially be responsible for defense morph formation. In addition, the juvenile hormone pathway genes, JHAMT and Met, and the insulin signaling pathway genes, InR and IRS-1, were up-regulated in the first-instar stage. It is well known that these hormonal pathways are involved in physiological regulation following morphogenesis in many insect species. During the embryonic stage when morphotypes were determined, one of the novel genes identified by differential display was up-regulated, suggesting that this gene may be related to morphotype determination. Biological functions of the up-regulated genes are discussed in the context of defense morph formation.

Conclusions

It is suggested that, following the reception of kairomone signals, the identified genes are involved in a series of defensive phenotypic alterations and the production of a defensive phenotype.

     

The prevalence and genomic characteristics of hepatitis E virus in murine rodents and house shrews from several regions in China

Background

Urban rodents and house shrews are closely correlated in terms of location with humans and can transmit many pathogens to them. Hepatitis E has been confirmed to be a zoonotic disease. However, the zoonotic potential of rat HEV is still unclear. The aim of this study was to determine the prevalence and genomic characteristics of hepatitis E virus (HEV) in rodents and house shrews.

Results

We collected a total of 788 animals from four provinces in China. From the 614 collected murine rodents, 20.19% of the liver tissue samples and 45.76% of the fecal samples were positive for HEV. From the 174 house shrews (Suncus murinus), 5.17% fecal samples and 0.57% liver tissue samples were positive for HEV. All of the HEV sequences obtained in this study belonged to Orthohepevirus C1. However, we observed a lower percentage of identity in the ORF3 region upon comparing the amino acid sequences between Rattus norvegicus and Rattus losea. HEV derived from house shrews shared a high percentage of identity with rat HEV. Notably, the first near full-length of the HEV genome from Rattus losea is described in our study, and we also report the first near full-length rat HEV genomes in Rattus norvegicus from China.

Conclusion

HEV is prevalent among the three common species of murine rodents (Rattus. norvegicus, Rattus. tanezumi, and Rattus. losea) in China. HEV sequences detected from house shrews were similar to rat HEV sequences. The high identity of HEV from murine rodents and house shrews suggested that HEV can spread among different animal species.

     

Functional characterization of duplicated B-class MADS-box genes in Japanese gentian

Key message

The heterodimer formation between B-class MADS-box proteins of GsAP3a and GsPI2 proteins plays a core role for petal formation in Japanese gentian plants.

Abstract

We previously isolated six B-class MADS-box genes (GsAP3a, GsAP3b, GsTM6, GsPI1, GsPI2, and GsPI3) from Japanese gentian (Gentiana scabra). To study the roles of these MADS-box genes in determining floral organ identities, we investigated protein–protein interactions among them and produced transgenic Arabidopsis and gentian plants overexpressing GsPI2 alone or in combination with GsAP3a or GsTM6. Yeast two-hybrid and bimolecular fluorescence complementation analyses revealed that among the GsPI proteins, GsPI2 interacted with both GsAP3a and GsTM6, and that these heterodimers were localized to the nuclei. The heterologous expression of GsPI2 partially converted sepals into petaloid organs in transgenic Arabidopsis, and this petaloid conversion phenomenon was accelerated by combined expression with GsAP3a but not with GsTM6. In contrast, there were no differences in morphology between vector-control plants and transgenic Arabidopsis plants expressing GsAP3a or GsTM6 alone. Transgenic gentian ectopically expressing GsPI2 produced an elongated tubular structure that consisted of an elongated petaloid organ in the first whorl and stunted inner floral organs. These results imply that the heterodimer formation between GsPI2 and GsAP3a plays a core role in determining petal and stamen identities in Japanese gentian, but other B-function genes might be important for the complete development of petal organs.

     

Accumulation of large non-circular forms of the chromosome in recombination-defective mutants of <Emphasis Type="Italic">Escherichia coli</Emphasis>

Background

Double-strand breakage of chromosomal DNA is obviously a serious threat to cells because various activities of the chromosome depend on its integrity. However, recent experiments suggest that such breakage may occur frequently during "normal" growth in various organisms – from bacteria through vertebrates, possibly through arrest of a replication fork at some endogenous DNA damage.

Results

In order to learn how the recombination processes contribute to generation and processing of the breakage, large (> 2000 kb) linear forms of Escherichia coli chromosome were detected by pulsed-field gel electrophoresis in various recombination-defective mutants. The mutants were analyzed in a rich medium, in which the wild-type strain showed fewer of these huge broken chromosomes than in a synthetic medium, and the following results were obtained: (i) Several recB and recC null mutants (in an otherwise rec⁺ background) accumulated these huge linear forms, but several non-null recBCD mutants (recD, recC1001, recC1002, recC1003, recC1004, recC2145, recB2154, and recB2155) did not. (ii) In a recBC sbcA background, in which RecE-mediated recombination is active, recA, recJ, recQ, recE, recT, recF, recO, and recR mutations led to their accumulation. The recJ mutant accumulated many linear forms, but this effect was suppressed by a recQ mutation. (iii) The recA, recJ, recQ, recF and recR mutations led to their accumulation in a recBC sbcBC background. The recJ mutation showed the largest amount of these forms. (iv) No accumulation was detected in mutants affecting resolution of Holliday intermediates, recG, ruvAB and ruvC, in any of these backgrounds.

Conclusion

These results are discussed in terms of stepwise processing of chromosomal double-strand breaks.

     

New Middle Miocene Caviomorph Rodents from Quebrada Honda,Bolivia

The rodents of the middle Miocene fauna of Quebrada Honda Bolivia are described. The most abundant rodent is the chinchillid Prolagostomus sp. More precise identification of this species will require revision of early to middle Miocene lagostomines, taking into account variation in modern populations. The next most common rodents are the tiny octodontoid Acarechimys, sp. nov.?, and the caviid Guiomys unica. The Acarechimys species may be unique to Quebrada Honda, but verification awaits revision of this geographically and temporally widespread genus. Guiomys unica is a recently described species otherwise known only from two Patagonian localities, El Petiso and Río Chico. Two rodents are unique to Quebrada Honda. Mesoprocta hypsodus, gen. et sp. nov., is a dasyproctid distinguished by its very hypsodont, cement-covered cheek teeth. Quebradahondomys potosiensis, gen. et sp. nov., is an adelphomyine echimyid distinguished by the less oblique lophids of its trilophodont cheek teeth, among other features. The rodents of Quebrada Honda are more similar to those of Patagonia than those of northern South America, paralleling patterns seen in other mammal groups from this fauna.