Detection of Citrus leprosis virus C using specific primers and TaqMan probe in one-step real-time reverse-transcription polymerase chain reaction assays

Citrus leprosis virus C (CiLV-C), a causal agent of the leprosis disease in citrus, is mostly present in the South and Central America and spreading toward the North America. To enable better diagnosis and inhibit the further spread of this re-emerging virus a quantitative (q) real-time reverse transcription polymerase chain reaction (qRT-PCR) assay is needed for early detection of CiLV-C when the virus is present in low titer in citrus leprosis samples. Using the genomic sequence of CiLV-C, specific primers and probe were designed and synthesized to amplify a 73 nt amplicon from the movement protein (MP) gene. A standard curve of the 73 nt amplicon MP gene was developed using known 10(10)-10(1) copies of in vitro synthesized RNA transcript to estimate the copy number of RNA transcript in the citrus leprosis samples. The one-step qRT-PCR detection assays for CiLV-C were determined to be 1000 times more sensitive when compared to the one-step conventional reverse transcription polymerase chain reaction (RT-PCR) CiLV-C detection method. To evaluate the quality of the total RNA extracts, NADH dehydrogenase gene specific primers (nad5) and probe were included in reactions as an internal control. The one-step qRT-PCR specificity was successfully validated by testing for the presence of CiLV-C in the total RNA extracts of the citrus leprosis samples collected from Belize, Costa Rica, Mexico and Panama. Implementation of the one-step qRT-PCR assays for CiLV-C diagnosis should assist regulatory agencies in surveillance activities to monitor the distribution pattern of CiLV-C in countries where it is present and to prevent further dissemination into citrus growing countries where there is no report of CiLV-C presence.

Low haemoglobin concentration in Tibetan males is associated with greater high-altitude exercise capacity

Tibetans living at high altitude have adapted genetically such that many display a low erythropoietic response, resulting in near sea-level haemoglobin (Hb) concentration. We hypothesized that absence of the erythropoietic response would be associated with greater exercise capacity compared to those with high [Hb] as a result of beneficial changes in oxygen transport. We measured, in 21 Tibetan males with [Hb] ranging from 15.2 g dl(-1) to 22.9 g dl(-1) (9.4 mmol l(-1) to 14.2 mmol l(-1) ), [Hb], ventilation, volumes of O2 and CO2 utilized at peak exercise (V̇O2 and V̇CO2), heart rate, cardiac output and arterial blood gas variables at peak exercise on a cycle ergometer at ∼4200 m. Lung and muscle O2 diffusional conductances were computed from these measurements. [Hb] was related (negatively) to V̇O2 kg(-1) (r = -0.45, P< 0.05), cardiac output kg(-1) (QT kg(-1) , r = -0.54, P < 0.02), and O2 diffusion capacity in muscle (DM kg(-1) , r = -0.44, P<0.05), but was unrelated to ventilation, arterial partial pressure of O2 (PaO2) or pulmonary diffusing capacity. Using multiple linear regression, variance in peak V̇O2 kg(-1) was primarily attributed to QT, DM, and PCO2 (R(2) = 0.88). However, variance in pulmonary gas exchange played essentially no role in determining peak V̇O2. These results (1) show higher exercise capacity in Tibetans without the erythropoietic response, supported mostly by cardiac and muscle O2 transport capacity and ventilation rather than pulmonary adaptations, and (2) support the emerging hypothesis that the polycythaemia of altitude, normally a beneficial response to low cellular PO2, may become maladaptive if excessively elevated under chronic hypoxia. The cause and effect relationships among [Hb], QT, DM, and PCO2 remain to be elucidated.

XBP1 mitigates aminoglycoside-induced endoplasmic reticulum stress and neuronal cell death

Here we study links between aminoglycoside-induced mistranslation, protein misfolding and neuropathy. We demonstrate that aminoglycosides induce misreading in mammalian cells and assess endoplasmic reticulum (ER) stress and unfolded protein response (UPR) pathways. Genome-wide transcriptome and proteome analyses revealed upregulation of genes related to protein folding and degradation. Quantitative PCR confirmed induction of UPR markers including C/EBP homologous protein, glucose-regulated protein 94, binding immunoglobulin protein and X-box binding protein-1 (XBP1) mRNA splicing, which is crucial for UPR activation. We studied the effect of a compromised UPR on aminoglycoside ototoxicity in haploinsufficient XBP1 (XBP1^+/−) mice. Intra-tympanic aminoglycoside treatment caused high-frequency hearing loss in XBP1^+/− mice but not in wild-type littermates. Densities of spiral ganglion cells and synaptic ribbons were decreased in gentamicin-treated XBP1^+/− mice, while sensory cells were preserved. Co-injection of the chemical chaperone tauroursodeoxycholic acid attenuated hearing loss. These results suggest that aminoglycoside-induced ER stress and cell death in spiral ganglion neurons is mitigated by XBP1, masking aminoglycoside neurotoxicity at the organismal level.

Increased blood-oxygen binding affinity in Tibetan and Han Chinese residents at 4200 m

High-altitude natives are challenged by hypoxia, and a potential compensatory mechanism could be reduced blood oxygen-binding affinity (P50), as seen in several high-altitude mammalian species. In 21 Qinghai Tibetan and nine Han Chinese men, all resident at 4200 m, standard P50 was calculated from measurements of arterial PO2 and forehead oximeter oxygen saturation, which was validated in a separate examination of 13 healthy subjects residing at sea level. In both Tibetans and Han Chinese, standard P50 was 24.5 ± 1.4 and 24.5 ± 2.0 mmHg, respectively, and was lower than in the sea-level subjects (26.2 ± 0.6 mmHg, P < 0.01). There was no relationship between P50 and haemoglobin concentration (the latter ranging from 15.2 to 22.9 g dl(-1) in Tibetans). During peak exercise, P50 was not associated with alveolar-arterial PO2 difference or peak O2 uptake per kilogram. There appears to be no apparent benefit of a lower P50 in this adult high-altitude Tibetan population.

Phytoremediation of heavy and transition metals aided by legume-rhizobia symbiosis

Legumes are important for nitrogen cycling in the environment and agriculture due to the ability of nitrogen fixation by rhizobia. In this review, we introduce an important and potential role of legume-rhizobia symbiosis in aiding phytoremediation of some metal contaminated soils as various legumes have been found to be the dominant plant species in metal contaminated areas. Resistant rhizobia used for phytoremediation could act on metals directly by chelation, precipitation, transformation, biosorption and accumulation. Moreover, the plant growth promoting (PGP) traits of rhizobia including nitrogen fixation, phosphorus solubilization, phytohormone synthesis, siderophore release, and production of ACC deaminase and the volatile compounds of acetoin and 2, 3-butanediol may facilitate legume growth while lessening metal toxicity. The benefits of using legumes inoculated with naturally resistant rhizobia or recombinant rhizobia with enhanced resistance, as well as co-inoculation with other plant growth promoting bacteria (PGPB) are discussed. However, the legume-rhizobia symbiosis appears to be sensitive to metals, and the effect of metal toxicity on the interaction between legumes and rhizobia is not clear. Therefore, to obtain the maximum benefits from legumes assisted by rhizobia for phytoremediation of metals, it is critical to have a good understanding of interactions between PGP traits, the symbiotic plant-rhizobia relationship and metals.

S-phase kinase-associated protein 2 knockdown blocks colorectal cancer growth via regulation of both p27 and p16 expression

The objective of this study was to determine the role and mechanism of S-phase kinase-associated protein 2 (Skp2) in colorectal cancer cell proliferation and survival both in vitro and in vivo. Adenoviral vector expressing Skp2 short hairpin RNA was transduced into SW480 cells. The effects of Skp2 on cell cycle and survival were assessed by Flow Cytometry. Cell proliferation was analyzed by MTT assay. The expression of cell cycle regulators p16 and p27 were measured by western blot. In vivo, human colorectal cancer was produced by xenograft of cancer cells in nude mouse. Tumor growth inhibitory rate was calculated to generate growth curve. Tumor growth was monitored by examining proliferating cell nuclear antigen expression, whereas tumor cell apoptosis was detected by TdT-mediated dUTP nick-end labeling (TUNEL) staining. Knockdown of Skp2 blocked SW480 tumor cell growth and induced cell apoptosis. Skp2 appeared to be very important for the progression of cell cycle at G1/S phase. In vivo, blockade of Skp2 expression inhibited tumor growth and induced tumor apoptosis. Mechanistically, Skp2 regulated the expression of both p27 and p16 both in vitro and in vivo. The conclusion that we derive from this study is that Skp2 regulates colorectal cancer cell growth by inhibiting the expression of cell cycle regulator p27 and p16.

The cultivable human oral gluten-degrading microbiome and its potential implications in coeliac disease and gluten sensitivity

Coeliac disease is characterized by intestinal inflammation caused by gluten, proteins which are widely contained in the Western diet. Mammalian digestive enzymes are only partly capable of cleaving gluten, and fragments remain that induce toxic responses in patients with coeliac disease. We found that the oral microbiome is a novel and rich source of gluten-degrading organisms. Here we report on the isolation and characterization of the cultivable resident oral microbes that are capable of cleaving gluten, with special emphasis on the immunogenic domains. Bacteria were obtained by a selective culturing approach and enzyme activities were characterized by: (i) hydrolysis of paranitroanilide-derivatized gliadin-derived tripeptide substrates; (ii) gliadin degradation in-gel (gliadin zymography); (iii) gliadin degradation in solution; (iv) proteolysis of the highly immunogenic α-gliadin-derived 33-mer peptide. For selected strains pH activity profiles were determined. The culturing strategy yielded 87 aerobic and 63 anaerobic strains. Species with activity in at least two of the four assays were typed as: Rothia mucilaginosa HOT-681, Rothia aeria HOT-188, Actinomyces odontolyticus HOT-701, Streptococcus mitis HOT-677, Streptococcus sp. HOT-071, Neisseria mucosa HOT-682 and Capnocytophaga sputigena HOT-775, with Rothia species being active in all four assays. Cleavage specificities and substrate preferences differed among the strains identified. The approximate molecular weights of the enzymes were ~75 kD (Rothia spp.), ~60 kD (A. odontolyticus) and ~150 kD (Streptococcus spp.). In conclusion, this study identified new gluten-degrading microorganisms in the upper gastrointestinal tract. A cocktail of the most active oral bacteria, or their isolated enzymes, may offer promising new treatment modalities for coeliac disease.

The cultivable human oral gluten-degrading microbiome and its potential implications in coeliac disease and gluten sensitivity

Coeliac disease is characterized by intestinal inflammation caused by gluten, proteins which are widely contained in the Western diet. Mammalian digestive enzymes are only partly capable of cleaving gluten, and fragments remain that induce toxic responses in patients with coeliac disease. We found that the oral microbiome is a novel and rich source of gluten-degrading organisms. Here we report on the isolation and characterization of the cultivable resident oral microbes that are capable of cleaving gluten, with special emphasis on the immunogenic domains. Bacteria were obtained by a selective culturing approach and enzyme activities were characterized by: (i) hydrolysis of paranitroanilide-derivatized gliadin-derived tripeptide substrates; (ii) gliadin degradation in-gel (gliadin zymography); (iii) gliadin degradation in solution; (iv) proteolysis of the highly immunogenic α-gliadin-derived 33-mer peptide. For selected strains pH activity profiles were determined. The culturing strategy yielded 87 aerobic and 63 anaerobic strains. Species with activity in at least two of the four assays were typed as: Rothia mucilaginosa HOT-681, Rothia aeria HOT-188, Actinomyces odontolyticus HOT-701, Streptococcus mitis HOT-677, Streptococcus sp. HOT-071, Neisseria mucosa HOT-682 and Capnocytophaga sputigena HOT-775, with Rothia species being active in all four assays. Cleavage specificities and substrate preferences differed among the strains identified. The approximate molecular weights of the enzymes were ~75 kD (Rothia spp.), ~60 kD (A. odontolyticus) and ~150 kD (Streptococcus spp.). In conclusion, this study identified new gluten-degrading microorganisms in the upper gastrointestinal tract. A cocktail of the most active oral bacteria, or their isolated enzymes, may offer promising new treatment modalities for coeliac disease.

A novel virus of the genus Cilevirus causing symptoms similar to citrus leprosis

Citrus leprosis in Colombia was previously shown to be caused by cytoplasmic Citrus leprosis virus (CiLV-C). In 2011, enzyme-linked immunosorbent assay and reverse-transcription polymerase chain reaction (RT-PCR)-based diagnostic methods failed to identify CiLV-C from citrus samples with symptoms similar to citrus leprosis; however, virions similar to CiLV-C were observed in the cytoplasm of the symptomatic leaves by transmission electron microscopy. Furthermore, the causal organism was transmitted by the false spider mite, Brevipalpus phoenicis, to healthy citrus seedlings. A library of small RNAs was constructed from symptomatic leaves and used as the template for Illumina high-throughput parallel sequencing. The complete genome sequence and structure of a new bipartite RNA virus was determined. RNA1 (8,717 nucleotides [nt]) contained two open reading frames (ORFs). ORF1 encoded the replication module, consisting of five domains: namely, methyltransferase (MTR), cysteine protease-like, FtsJ-MTR, helicase (Hel), and RNA-dependent RNA polymerase (RdRp); whereas ORF2 encoded the putative coat protein. RNA2 (4,989 nt) contained five ORFs that encode the movement protein (MP) and four hypothetical proteins (p7, p15, p24, and p61). The structure of this virus genome resembled that of CiLV-C except that it contained a long 3' untranslated terminal region and an extra ORF (p7) in RNA2. Both the RNA1 and RNA2 of the new virus had only 58 and 50% nucleotide identities, respectively, with known CiLV-C sequences and, thus, it appears to be a novel virus infecting citrus. Phylogenetic analyses of the MTR, Hel, RdRp, and MP domains also indicated that the new virus was closely related to CiLV-C. We suggest that the virus be called Citrus leprosis virus cytoplasmic type 2 (CiLV-C2) and it should be unambiguously classified as a definitive member of the genus Cilevirus. A pair of CiLV-C2 genome-specific RT-PCR primers was designed and validated to detect its presence in citrus leprosis samples collected from the Casanare and Meta states in Colombia.

Epidemic trend of measles in Shandong Province, China, 1963-2005

OBJECTIVES

Although measles is a vaccine-preventable infectious disease and the measles vaccine is safe and effective, it still poses a serious threat to the health of children and susceptible populations in China every year. This study aimed to investigate the epidemiological characteristics of measles in Shandong Province, China, including its spatial distribution pattern, in order to have a precise prediction of measles epidemics for better public health strategic planning and resource allocation.

STUDY DESIGN

Longitudinal data study.

METHODS

This study was based on the surveillance data set of measles from all 17 regions (cities) in Shandong Province between 1963 and 2005. Geographical Information Systems and piecewise exponential smoothing of logarithmic transformed data were applied with consideration of the spatial and temporal features of the data. The parameters of epidemic peaks were estimated by filtering off the drifting long-term trends.

RESULTS

Measles presented in almost all regions in Shandong Province with different spatial distribution over the 43-year study period. The incidence of measles was very high in the pre-vaccination period, with an average incidence of 617.61/100,000 population in 1963. With the implementation of vaccination, the average incidence of measles decreased to 3.63/100,000 population in 2005, the periodicity died out and the trend remained at a stable low level. Outbreaks have been reported recently.

CONCLUSIONS

This study identified the effects of different strategies on the incidence of measles observed in Shandong, China, and will provide valuable information to assist local and national public health policy making. There are still some challenges to improve vaccination coverage and efficacy in order to eliminate measles in China. Strengthening surveillance will be essential in the framework of the anticipated global elimination campaign for measles.

A phase I study of sunitinib in combination with FOLFIRI in patients with untreated metastatic colorectal cancer

BACKGROUND

This study evaluated the maximum tolerated dose (MTD) of sunitinib, a multitargeted tyrosine kinase inhibitor, combined with FOLFIRI (irinotecan 180 mg/m2 given over 90 min i.v. and l-leucovorin 200 mg/m2 given over 120 min on day 1, followed by 5-FU 400 mg/m2 bolus and then 2400 mg/m2 infused over 46 h) in untreated metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

In this multicentre, phase I, open-label, dose-finding trial, FOLFIRI was administered every 2 weeks. Two sunitinib regimens were explored: Schedule 4/2 (4 weeks on, 2 weeks off; 37.5 and 50 mg/day) and continuous daily dosing (CDD; 37.5 and 25 mg/day). Dose-limiting toxic toxicities (DLTs) were evaluated during weeks 1-6. Efficacy was a secondary objective.

RESULTS

Thirty-seven patients were enrolled. The 37.5 mg/day Schedule 4/2 cohort had zero of six DLTs, was expanded by 15 patients and declared the MTD. The MTD was exceeded at all other sunitinib doses and schedules; DLTs included febrile neutropenia (n=1), grade 4 neutropenia (n=4) and grade 3 deep vein thrombosis with grade 4 neutropenia (n=1). At the MTD, non-haematologic grade 3/4 adverse events with a frequency of >10% were diarrhoea, vomiting and lethargy, and the objective response rate was 57.9% (95% confidence interval 33.5-79.7).

CONCLUSIONS

The MTD of sunitinib combined with FOLFIRI in chemotherapy-naive mCRC was 37.5 mg/day on Schedule 4/2. CDD of sunitinib at 37.5 or 25 mg/day plus FOLFIRI was not feasible.

Cytomegalovirus infection in mesenchymal stem cells and their activation could be enhanced by nuclear factor-κB inhibitor pyrrolidinedithiocarbamate in vitro

Because of the central role of the transcription factor nuclear factor (NF)-κB in cell survival and proliferation in many kinds of cancer cells, NF-κB inhibitors may have a potential role in cancer therapy. Currently, many NF-κB inhibitors are used for immunosuppression to treat hematologic malignancy patients after stem cell transplantation (SCT). Human cytomegalovirus (HCMV) infection is one of the most common complications following SCT. Some workers have reported that HCMV infection has a close relationship to NF-κB activation; however, the specific effects of NF-κB inhibitors, such as pyrrolidinedithiocarbamate (PDTC), on infection with and activation of CMV in mesenchymal stem cells (MSCs) remain unknown. In our study, we isolated MSCs from the bone marrows of healthy human donors for infection with 1 tcid(50) of HCMV with or without 1 μmol/L PDTC. After 48 hours of culture in dmem supplemented with 10% (volume per volume) fetal calf serum, we tested MSCs using reverse transcription-polymerase chain reaction (RT-PCR) assays to detect messenger RNA (mRNA) expression of HCMV immediate early (IE) gene and the GAPDH gene. Flow cytometry was used to detect HCMV pp65 antigen-positive cells and transmission electron microscopy (TEM) for intra cellular HCMV particles. We observed that the shape of the MSCs changed in response to infection by 1 TCID(50) of HCMV. MSCs infected by 1 TCID(50) of HCMV in combination with 1 μmol/L of PDTC changed their shapes more profoundly; almost all cells went from a thin elongated profile to a round, thick ball. In contrast, the shape of cells treated with PDTC alone or the HCMV mock-infected elements did not change. The RT-PCR assay showed that there was a bright band corresponding to HCMV IE mRNA in MSCs infected with 1 TCID(50) of HCMV in combination with 1 μmol/L of PDTC, as compared with cells infected by only 1 TCID(50) of HCMV. The HCMV mock-infected MSCs did not express HCMV IE mRNA. Using flow cytometry, we detected more HCMV pp65 antigen-positive cells among MSCs infected with 1 TCID(50) of HCMV in combination with 1 μmol/L of PDTC. HCMV particles were observed by TEM in the nucleus and cytoplasm of MSCs infected with HCMV. There were more HCMV particles in cells infected by HCMV in combination with PDTC. In conclusion, NF-κB activation may affect HCMV infection efficiency of MSCs. An NF-κB inhibitor increased the infection by activation of HCMV in MSCs, thus we should pay close attention to HCMV infection when we prescribe an NF-κB inhibitor in clinical settings.

Hipk2 cooperates with p53 to suppress γ-ray radiation-induced mouse thymic lymphoma

A genome-wide screen for genetic alterations in radiation-induced thymic lymphomas generated from p53+/- and p53-/- mice showed frequent loss of heterozygosity (LOH) on chromosome 6. Fine mapping of these LOH regions revealed three non-overlapping regions, one of which was refined to a 0.2 Mb interval that contained only the gene encoding homeobox-interacting protein kinase 2 (Hipk2). More than 30% of radiation-induced tumors from both p53+/- and p53-/- mice showed heterozygous loss of one Hipk2 allele. Mice carrying a single inactive allele of Hipk2 in the germline were susceptible to induction of tumors by γ-radiation, but most tumors retained and expressed the wild-type allele, suggesting that Hipk2 is a haploinsufficient tumor suppressor gene for mouse lymphoma development. Heterozygous loss of both Hipk2 and p53 confers strong sensitization to radiation-induced lymphoma. We conclude that Hipk2 is a haploinsufficient lymphoma suppressor gene.

Erythropoietin promotes spinal cord-derived neural progenitor cell proliferation by regulating cell cycle

Erythropoietin (EPO) regulates the proliferation and differentiation of erythroid cells by binding to its specific transmembrane receptor (EPOR). The presence of EPO and its receptor in the CNS suggests a different function for EPO other than erythropoiesis. The purpose of the present study was to examine EPOR expression and the role of EPO in the proliferation of neonatal spinal cord-derived neural progenitor cells. The effect of EPO on cell cycle progression was also examined, as well as the signaling cascades involved in this process. Our results showed that EPOR was present in the neural progenitor cells and EPO significantly enhanced their proliferation. Cell cycle analysis of EPO-treated neural progenitor cells indicated a reduced percentage of cells in G0/G1 phase, whereas the cell proliferation index (S phase plus G2/M phase) was increased. EPO also increased the proportion of 5-bromo-2-deoxyuridine (BrdU)-positive cells. With respect to the cell cycle signaling, we examined the cyclin-dependent kinases D1, D2 and E, and cyclin-dependent kinase inhibitors, p21cip1, p27kip1 and p57kip2. No significant differences were observed in the expression of these transcripts after EPO administration. Interestingly, the anti-apoptotic factors, mcl-1 and bcl-2 were significantly increased twofold. Moreover, these specific effects of EPO were eliminated by incubation of the progenitor cells with anti-EPO neutralizing antibody. Those observations suggested that EPO may play a role in normal spinal cord development by regulating cell proliferation and apoptosis.

Importance of normothermia control in investigating delayed neuronal injury in a mouse global ischemia model

This study aims to establish a mouse global cerebral ischemia model in which the physiological parameter measurements and neuronal injury evaluations are conducted in the same group of animals and to identify the effect of post-ischemic core temperature (CT) on the outcome of neuronal injury. Global ischemia was induced by 12-min bilateral common carotid artery occlusion followed by 7 days of reperfusion in C57BL/6 mice. Immediately after occlusion, mice were randomly assigned to be kept in environments of different temperatures [25 degrees C (room temperature, group 1), 33-34 degrees C for 2h (group 2), and 33-34 degrees C for 24h (group 3)] before being returned to their home cages. We found that in group 1, CT declined to approximately 32 degrees C after ischemia and then recovered at 24h post-ischemia; in group 2, CT remained at the pre-ischemia level during the first 2h, declined after the mice were returned to room temperature, and recovered at 24h post-ischemia; and in group 3, CT remained constant at the pre-ischemia level throughout the reperfusion period. The number of surviving neurons in a sector of the hippocampal CA1 region was significantly lower in all ischemic groups than in the sham controls, but the number was significantly higher in group 1 than that in groups 2 or 3 (P<0.05). We observed that CT declines initially but recovers spontaneously at 24h post-ischemia. Early post-ischemic hypothermia impacts the delayed neuronal injury, suggesting that tight temperature control immediately following ischemia is important to obtain the most reproducible neuronal damage in mouse models of cerebral global ischemia.

Prostacyclin receptor deletion aggravates hippocampal neuronal loss after bilateral common carotid artery occlusion in mouse

Transient global cerebral ischemia causes delayed neuronal death in the hippocampal CA1 region. It also induces an increase in cyclooxygenase 2 (COX-2), which generates several metabolites of arachidonic acid, known as prostanoids, including prostacyclin (PGI(2)). To determine the role of the PGI(2) receptor (IP) in post-ischemic delayed cell death, wild-type and IP knockout (IP(-/-)) C57Bl/6 mice were subjected to 12-min bilateral common carotid artery occlusion or sham surgery, followed by 7 days of reperfusion. In the sham-operated mice, no statistical difference in CA1 hippocampal neuronal density was observed between the wild-type (2836+/-18/mm(2)) and IP(-/-) (2793+/-43/mm(2)) mice. Interestingly, in animals subjected to ischemia, surviving neuronal density in wild-type mice decreased to 50.5+/-7.9% and that of IP(-/-) mice decreased to 23.0+/-4.5% of their respective sham-operated controls (P<0.05). The results establish a role for the IP receptor in protecting pyramidal hippocampal neurons after this global ischemic model and suggest that IP receptor agonists could be developed to prevent delayed pyramidal neuronal cell death.

An animal model of human cytomegalovirus infection

To develop a rat model that allowed in vivo progressive human cytomegalovirus (HCMV) infection, allogeneic liver transplantation was performed across a rat combination of Dark Agouti (DA) to Brown Norway (BN). AD169, a well-characterized laboratory strain of HCMV, was used to establish a rat model of HCMV infection by injection of 0.4 mL (30.0 logTCID50) supernate into the rat peritoneum. Histological and blood specimens were obtained from animals sacrificed at predetermined timepoints. We performed immunohistochemical staining in liver, heart, kidney, spleen, and lung for HCMV immediate-early antigen (IE), lower matrix protein (pp65) detection in peripheral blood leukocytes, and HCMV early antigen (EA) and late antigen (LA). We compared survival rates. Our results showed positive HCMV IE and pp65 antigenemia detected in peripheral blood leukocytes in transplanted recipients from day 1 to day 30. Positive HCMV EA and LA staining cells were only detected in sections 10 days after liver transplantation, namely, in hepatocytes, mononuclear cells, bile duct epithelial cells, and endothelial cells. Successful HCMV replication was due to the combination of liver transplantation and cyclosporine (CsA) immunosuppression. Survival analysis showed no significant differences between the HCMV-infected group and HCMV-uninfected group. This new rat model of HCMV infection may be helpful to understand immune system modulation of HCMV infection.

Sex determination of germ cells in Drosophila

Many lines of evidence indicate that in Drosophila the mechanism for establishing the sex of the female germline is different from that acting in somatic cells. In the soma Sxl has an embryonic determinative role and is required throughout the life of female flies; in germ cells its expression begins only in the larval ovary. Both the mechanism for activating Sxl and the genes controlled by Sxl are different in the germline. A number of genes have been identified that are essential either for survival (e.g. ovo, otu) or differentiation (snf, Sxl, fl(2)d, bgcn) of female germ cells. ovo is required during embryogenesis for survival of pole cells. Genetic interactions with dominant alleles of ovo and/or Sxl indicate that otu, Sxl, snf and fl(2)d act in the same pathway as does ovo. bgcn differs in that neither ovo nor SxlD mutations affect the bgcn phenotype even though XX bgcn germ cells enter the male pathway. bgcn causes sterility in both sexes. Although the germline defect is cell autonomous in mosaic gonads, bgcn is also required in the somatic tissue for maintaining oogenesis of wild-type germ cells. Several dominant suppressors of bgcn have been identified and some have properties similar to Suppressors of variegation, suggesting that chromatin structure is critical for proper germ cell sex determination.