Differential gene expression in two consecutive pregnancies between same sex siblings and implications on maternal constraint

The objective of this study was to investigate how placental gene expression differs in two consecutive pregnancies in same sex siblings, and its possible association with the "maternal constraint" hypothesis. Material was gathered from the BASIC study (Biological, Affect, Stress, Imaging, and Cognition in Pregnancy and the Puerperium), a population based prospective study that was started in 2009 in Uppsala. Over 900 specimens of placenta biopsies were collected and out of these 10 women gave birth twice, to the same sex child, and were included in this study. The total RNA was isolated and prepared from frozen villous tissue from the placenta and further analyzed by use of Ion AmpliSeq Human Transcriptome Gene Expression kit. A total of 234 genes differed significantly between the first and second pregnancy placentas, when adjusting for delivery mode, maternal BMI and gestational age. Of special interest was the down-regulated group of genes in the second pregnancy. Exemplified by Pentraxin 3, SRY-Box Transcription Factor 9, and Serum Amyloid A1, which all were associated with biological processes involved in the immune system and inflammation. Further, protein-protein interaction analysis visualized them as hub genes interacting with several of the other differentially expressed genes. How these altered gene expressions affect maternal constraint during pregnancy needs further validation in lager study cohorts and also future validation in functional assays.

Identification of phthalate mixture exposure targets in the human and mouse ovary in vitro

Chemical health risk assessment is based on single chemicals, but humans and wildlife are exposed to extensive mixtures of industrial substances and pharmaceuticals. Such exposures are life-long and correlate with multiple morbidities, including infertility. How combinatorial effects of chemicals should be handled in hazard characterization and risk assessment are open questions. Further, test systems are missing for several relevant health outcomes including reproductive health and fertility in women. Here, our aim was to screen multiple ovarian cell models for phthalate induced effects to identify biomarkers of exposure. We used an epidemiological cohort study to define different phthalate mixtures for in vitro testing. The mixtures were then tested in five cell models representing ovarian granulosa or stromal cells, namely COV434, KGN, primary human granulosa cells, primary mouse granulosa cells, and primary human ovarian stromal cells. Exposures at epidemiologically relevant levels did not markedly elicit cytotoxicity or affect steroidogenesis in short 24-hour exposure. However, significant effects on gene expression were identified by RNA-sequencing. Altogether, the exposures changed the expression of 124 genes on the average (9-479 genes per exposure) in human cell models, without obvious concentration or mixture-dependent effects on gene numbers. The mixtures stimulated distinct changes in different cell models. Despite differences, our analyses suggest commonalities in responses towards phthalates, which forms a starting point for follow-up studies on identification and validation of candidate biomarkers that could be developed to novel assays for regulatory testing or even into clinical tests.

Evaluation of Potency and Duration of Immunity Elicited by a Multivalent FMD Vaccine for Use in South Africa

South Africa (SA) experiences sporadic foot and mouth disease (FMD) outbreaks irrespective of routine prophylactic vaccinations of cattle using imported commercial vaccines. The problem could be mitigated by preparation of vaccines from local virus strains related to those circulating in the endemically infected buffalo populations in the Kruger National Park (KNP). This study demonstrates the individual number of protective doses (PD) of five vaccine candidate strains after homologous virus challenge, as well as the vaccines safety and onset of humoral immunity in naïve cattle. Furthermore, the duration of post-vaccination immunity over a 12-month period is shown, when a multivalent vaccine prepared from the five strains is administered as a primary dose with or without booster vaccinations. The five monovalent vaccines were shown to contain a 50% PD between 4 and 32, elicit humoral immunity with antibody titers ≥2.0 log10 from day 7 post-vaccination, and cause no adverse reactions. Meanwhile, the multivalent vaccine elicited antibody titers ≥2.0 log10 and clinical protection up to 12 months when one or two booster vaccinations were administered within 6 months of the primary vaccination. An insignificant difference between the application of one or two booster vaccinations was revealed. Owing to the number of PDs, we anticipate that the multivalent vaccine could be used successfully for prophylactic and emergency vaccinations without adjustment of the antigen payloads. Furthermore, a prophylactic vaccination regimen comprising primary vaccination of naïve cattle followed by two booster vaccinations 1.5 and 6 months later could potentially maintain herd immunity over a period of 12 months.

Endocrine disrupting chemicals interfere with decidualization of human primary endometrial stromal cells in vitro

Multiple studies have shown associations between exposure to endocrine disrupting chemicals (EDCs) and reduced fertility in women. However, little is known about the target organs of chemical disruption of female fertility. Here, we focus on the hormone-sensitive uterine lining, the endometrium, as a potential target. Decidualization is the morphological and functional change that endometrial stromal cells undergo to support endometrial receptivity, which is crucial for successful implantation, placentation, and pregnancy. We investigated the effect of nine selected EDCs on primary human endometrial stromal cell decidualization in vitro. The cells were exposed to a decidualization-inducing mixture in the presence or absence of 1 μM of nine different EDCs for nine days. Extent of decidualization was assessed by measuring the activity of cAMP dependent protein kinase, Rho-associated coiled-coil containing protein kinase, and protein kinase B in lysates using photoluminescent probes, and secretion of prolactin into the media by using ELISA. Decidualization-inducing mixture upregulated activity of protein kinases and prolactin secretion in cells derived from all women. Of the tested chemicals, dichlorodiphenyldichloroethylene (p,p'-DDE), hexachlorobenzene (HCB) and perfluorooctanesulfonic acid (PFOS) significantly reduced decidualization as judged by the kinase markers and prolactin secretion. In addition, bisphenol A (BPA) reduced prolactin secretion but did not significantly affect activity of the kinases. None of the EDCs was cytotoxic, based on the assessment of total protein content or activity of the viability marker casein kinase 2 in lysates. These results indicate that EDCs commonly present in the blood circulation of reproductive-aged women can reduce decidualization of human endometrial stromal cells in vitro. Future studies should focus on detailed hazard assessment to define possible risks of EDC exposure to endometrial dysfunction and implantation failure in women.

Laser-scanning in vivo confocal microscopy reveals two morphologically distinct populations of stromal nerves in normal human corneas

BACKGROUND

The purpose of this study was to use laser scanning in vivo confocal microscopy to elucidate the location and morphology of stromal nerves in the normal human central cornea.

METHODS

Analysis was performed via an established database of laser-scanning in vivo confocal microscopy on images of the central cornea of normal subjects. The depth and morphology of the stromal nerves were determined.

RESULTS

The population of this study consisted of 99 eyes of 99 healthy subjects (38 male, 61 female). The mean age of the group was 34.7 (SD 13.3, range 13-84) years. Two morphologically different populations of stromal nerves were observed: (1) straight, dichotomous branching nerves; and (2) tortuous nerves with a beaded appearance. The mean recorded depth of straight stromal nerves (186 (SD 66) mum) was significantly deeper than the mean depth of the tortuous stromal nerves (140 (SD 87) mum) (p<0.001).

CONCLUSIONS

The current study identified two morphologically distinct stromal nerve populations in the normal human cornea. We hypothesise that the two morphological nerve populations described here may represent functionally heterogeneous nerves. Further research is required to determine if these in fact represent different types of sensory nerves.

Veterinary vaccines for public health and prevention of viral and bacterial zoonotic diseases

To meet with the increasing demand for food, the scale of world food production is increasing, as is the transport of animals and food products. At the same time, the contact of animals with the environment remains unchanged or, in the case of free-ranging animals, is even increasing. A number of microorganisms have established themselves in farmed animals, which although relatively harmless to animals are pathogenic to man. In this article, the options for reducing the risk of transferring zoonotic agents from animals (particularly farm animals) to man using veterinary vaccines against viral and bacterial diseases are described.

Differentiating infection from vaccination in foot-and-mouth-disease: evaluation of an ELISA based on recombinant 3ABC

Recent devastating outbreaks of foot-and-mouth disease (FMD) in Europe have reopened the discussion about the adequacy of the non-vaccination strategy implemented by the EU in 1991. Here we describe the evaluation of a new commercially available test kit for the discrimination between vaccination and infection. The test is based on the detection of antibodies against the recombinant non-structural (NS) protein 3ABC. In contrast to immunization with vaccines free of 3ABC, these antibodies are elicited as a consequence of infection. Testing more than 3600 negative sera from several countries revealed a specificity of > 99% for bovine, ovine, and porcine samples. Antibodies specific for 3ABC can be detected as soon as 10 days post-infection. As compared with the occurrence of antibodies against structural proteins of FMDV, anti-3ABC antibodies can be detected 5-10 days later, depending on the species. No anti-3ABC antibodies were detected in sera from vaccination experiments or in field sera from vaccinated animals. However, anti-3ABC antibodies can be detected in vaccinated animals upon challenge. These results provide evidence that this test can facilitate the use of vaccines in new strategies against FMD.

[Vaccination against foot and mouth disease: current state and perspectives]

Foot-and-mouth disease (FMD) is endemic in many parts of the world and poses a permanent threat for cloven-hoofed animals in all countries. The available vaccines against FMD are safe and efficacious. Combat of FMD by vaccination is controversial in currently FMD-free countries including the ones of the European Union. The article summarizes our knowledge concerning production and use of vaccines, virus persistence, differentiation between vaccinated and infected animals, vaccination programs and perspectives of vaccine development.

Efficacy of the classical swine fever (CSF) marker vaccine Porcilis Pesti in pregnant sows

The efficacy of the classical swine fever (CSF) subunit marker vaccine Porcilis Pesti based on baculovirus expressed envelope glycoprotein E2 of CSF virus (CSFV) was evaluated in pregnant sows. Ten gilts were vaccinated with one dose of marker vaccine, followed by a second dose 4 weeks later. Four gilts remained unvaccinated and received a placebo at the same times. Thirty-three days after the second vaccination all animals were artificially inseminated. Neither local or systemic reactions nor an increase of body temperature were observed after vaccinations. All gilts showed a normal course of pregnancy. Thirty-five days after first vaccination all animals developed E2 specific neutralising antibodies with titres in the range of 5.0 and 7.5 log(2). No antibodies to CSFV-E(rns) were found in ELISA. On day 65 of gestation (126 days after the first immunisation) all sows were infected intranasally using 2ml (10(6.6) TCID(50)/ml) of the low virulent CSFV strain "Glentorf". After challenge in two of the unvaccinated control sows a slight transient increase of body temperature was observed, whereas leukopenia was demonstrated in all control animals. In addition all controls became viraemic. Vaccinations with the CSFV subunit vaccine protected the animals from clinical symptoms of CSF. In two sows a moderate decrease of leukocyte counts was detected on day 5 post infection. In contrast to the unvaccinated control sows in none of the vaccinated animals virus was isolated from the nasal swabs or the blood. Approximately 40 days after challenge all sows were killed and necropsy was done. The sows and their offspring were examined for the presence of CSFV in blood, bone marrow and different organs. No virus was found in any of the sows. In contrast, in all litters of the control sows CSFV was found in the blood as well as in the organ samples. Nine out of 10 litters of the vaccinated sows were protected from CSFV infection. Blood samples, lymphatic organs and bone marrow of these animals were all virologically negative. When sera were tested for CSFV-antibodies all sows had developed E(rns)-specific antibodies but no CSFV-specific antibodies were found in any of the progeny. It was concluded that vaccination with CSF subunit marker vaccine Porcilis((R)) Pesti protected 90% of the litters from viral infection when sows were challenged mid-gestation using the CSFV-strain "Glentorf".

Cell culture-grown putative bovine respiratory torovirus identified as a coronavirus

A putative bovine respiratory torovirus (BRTV) was propagated in bovine fetal diploid lung and human colonic tumour cells, and fringed pleomorphic particles were detected in the culture supernatants by electron microscopy. Antisera directed against a bovine (Breda strain) and equine (Berne strain) torovirus failed to react with BRTV-infected cells in immunofluorescence assays and did not neutralise BRTV. No toroviral RNA was found in the supernatants of infected cells by means of a reverse transcriptase-polymerase chain reaction with torovirus-specific primers. On the other hand, bovine coronavirus-specific antisera and monoclonal antibodies did neutralise the cytopathic effects, and coronaviral antigen was detected in the cultures by immunofluorescence. Furthermore, bovine coronavirus RNA was detected in the supernatants of BRTV-infected cells after nucleic acid amplification. It is concluded that the cytopathic BRTV isolate is a coronavirus.

Protection of pigs against Aujeszky's disease by DNA vaccination

Vaccination with DNA constructs encoding viral antigens has been shown to induce antiviral immunity in various model hosts. However, relevant natural virus-host systems have so far been analysed to only a very limited extent. To test the efficacy of DNA vaccination in an economically important large animal, pigs were immunized against Aujeszky's disease, a serious virus infection caused by the alphaherpesvirus pseudorabies virus (PrV), which is characterized by severe central nervous and respiratory symptoms. After vaccination with plasmid vectors containing genes for immunogenic envelope glycoproteins C or D (gC or gD) of PrV under control of the major immediate early promotor of human cytomegalovirus, animals developed serum antibodies which recognized the respective antigen in immunoblot and exhibited neutralizing activity. Animals vaccinated with the gC expression plasmid were fully protected against a lethal challenge with PrV strain 75V19, and showed partial protection against the highly virulent NIA-3 strain. In contrast, protection was not observed after vaccination with the gD plasmid. Three intramuscular or intradermal immunizations with as little as 1 microgram of gC plasmid DNA resulted in sero-conversion and partial protection against lethal NIA-3 Infection. Specific antibodies were detected until at least 9 months after vaccination. In addition, a cellular immune response specific for gC could be demonstrated in proliferation assays of peripheral mononuclear lymphocytes. Our results thus demonstrate the potency of DNA vaccination for protection of large animals against a lethal virus infection.

The pseudorabies virus UL51 gene product is a 30-kilodalton virion component

Positional homologs to the UL51 open reading frame of herpes simplex virus type 1 have been identified throughout the herpesvirus family. However, no respective protein has so far been described for any of the herpesviruses. With rabbit antisera directed against oligopeptides predicted to comprise antigenic regions of the deduced pseudorabies virus (PrV) UL51 protein, a polypeptide with a size of 30 kDa was identified in PrV-infected cell lysates and in purified virions. This molecular mass correlates reasonably well with the predicted mass of 25 kDa of the 236-amino-acid deduced UL51 protein. Antisera raised against peptides derived from different predicted antigenic regions all detected the 30-kDa protein in Western blot (immunoblot) analyses. Specificity was ascertained by peptide competition. Subcellular fractionation showed the presence of the UL51 protein mainly in the nucleus of infected cells. After separation of purified virion preparations into envelope and capsid, the PrV UL51 protein was detected in the capsid fraction. In summary, we identified the first herpesvirus UL51 protein and demonstrate that it represents a structural component of PrV virions.

Porcine reproductive and respiratory syndrome virus (PRRSV): monoclonal antibodies detect common epitopes on two viral proteins of European and U.S. isolates

Sixteen hybridoma cell lines secreting monoclonal antibodies (mAbs) directed against two dutch isolates of the causative virus of Porcine Reproductive and Respiratory Syndrome (PRRSV) were produced. The hybridoma cells resulted from fusions of SP2/0 myeloma cells with splenocytes of STU mice immunized with purified PRRSV after induction of immunotolerance against host cell constituents. Screening of supernatant fluids was performed by an indirect immunofluorescence assay on PRRSV-infected porcine alveolar macrophages. Immunoblotting studies revealed that the mAbs had different protein specificities. One mAb reacted with a viral 15 kD protein, eleven were directed against a 40-50 kD protein, and four against a 30-40 kD protein. The mAb against the 15 kD putative nucleocapsid protein as well as five mAbs against the 40-50 kD protein recognized epitopes on these proteins which are conserved in various European and U.S. isolates of PRRSV.

Identification and characterization of pseudorabies virus glycoprotein gM as a nonessential virion component

Sequence analysis within BamHI fragment 3 of the pseudorabies virus (PrV) genome revealed an open reading frame homologous to the UL10 gene of herpes simplex virus. A rabbit antiserum directed against a synthetic oligopeptide representing the carboxy-terminal 18 amino acids of the predicted UL10 product recognized a major 45-kDa protein in lysates of purified Pr virions. In addition, a second protein of 90 kDa which could represent a dimeric form was observed. Enzymatic deglycosylation showed that the PrV UL10 protein is N glycosylated. Therefore, it was designated PrV gM according to its homolog in herpes simplex virus. A PrV mutant lacking ca. 60% of UL10 coding sequences was able to productively replicate on noncomplementing cells, demonstrating that PrV gM is not required for viral replication in cell culture. However, infectivity of the mutant virus was reduced and penetration was delayed, indicating a modulatory role of PrV gM in the initiation of infection.

The vegetation and identification of management units of the Honnet Nature Reserve, Northern Province, South Africa

An analysis of the vegetation of the Honnet Nature Reserve, Northern Province is presented. Releves were compiled in 56 stratified random sample plots. The Braun- Blanquet procedure revealed 12 distinct plant communities and four sub-communities. The Variable Quadrant Plot Method was used in the structural analysis of the communities and management units. The data were ordinated using Detrended Correspondence Analysis (DECORANA) to determine possible relations and gradients between and in the plant communities. Six management units were identified by means of the vegetation ordination, plant communities and the physical environment. A hierarchical classification, description and ecological interpretation of the vegetation units and a descrip- tion of the management units are presented.

Mutations affecting the UL21 gene contribute to avirulence of pseudorabies virus vaccine strain Bartha

Analysis of the live attenuated pseudorabies virus (PrV) vaccine strain Bartha indicated location of a major determinant for PrV neurovirulence within the genomic BamHI fragment 4 (B. Lomniczi et al., 1984, J. Virol. 52, 198-205). To more precisely localize the defect, marker rescue experiments were performed using cloned subfragments of BamHI-4. Rescuants were analyzed after intracerebral infection for their virulence in chicken, as well as after intranasal infection for virulence in pigs. We show that the defect associated with attenuation in strain Bartha is located in a 3.8-kb subfragment of BamHI-4 which encompasses the PrV UL20 and UL21 genes and a putative origin of replication (B. Klupp, H. Kern, and T. C. Mettenleiter, 1992, Virology 191, 900-908). Sequence analysis of this region of the strain Bartha genome and comparison with the corresponding region in wild-type PrV strain Ka revealed the presence of eight point mutations. Four nucleotide exchanges reside within the UL21 gene with three of them leading to amino acid substitutions; one is located in the intergenic region between the UL20 and UL21 genes and three are localized downstream from the UL21 gene. Neither the UL20 gene nor the putative origin sequence was affected. Insertional inactivation of the UL21 gene in wild-type PrV strain Ka led to a marked attenuation of the virus for pigs infected by the intranasal route. In summary, our data show that the PrV UL21 gene is a major determinant of PrV virulence and that point mutations affecting the UL21 gene of live vaccine strain Bartha contribute to its attenuated phenotype.

A mouse model for testing the pathogenicity of equine herpes virus-1 strains

A mouse model was developed for testing the pathogenicity of equine herpes virus-1 (EHV-1) strains. The model was validated with EHV-1 strains that are known to be of a low or high pathogenicity in horses. From all parameters tested, the safety index, which was calculated from the body weights of the mice after infection, proved to be the best predictive parameter. When this parameter was used, good and reliable correlations were found with the pathogenicity of the EHV-1 strains in horses. This method enabled the differentiation between the two experimental EHV-1 strains whose genetic backgrounds were supposedly equal.

Characterization of a quadruple glycoprotein-deleted pseudorabies virus mutant for use as a biologically safe live virus vaccine

Herpesvirus envelope glycoproteins play important roles in mediating infection initiation and also represent major immunogens. We recently showed that a pseudorabies virus (PrV) mutant lacking the essential glycoprotein gD (gp50), after phenotypic complementation by propagation on genetically engineered PrV gD-expressing cell lines was able to infect primary target cells and spread exclusively by means of direct cell-to-cell transmission. Virions released from non-complementing cells that lacked gD were not infectious because of a defect in penetration and so free infectious virions did not arise after infection of animals by phenotypically complemented gD-negative PrV. This formed the basis for the development of novel non-spreading live herpes-virus vaccines. However, the gD-negative PrV mutant still retained a residual level of virulence, which prevented its use as vaccine, and the need to propagate the gD-negative PrV mutant on trans-complementing cell lines resulted in the appearance of wild-type revertants, rescued by the resident gene in the cell line. To overcome these problems we isolated a PrV mutant designated PrV(376) that, in addition to gD, also lacked the non-essential glycoproteins gG, gI and gE. PrV(376), because of the lack of gD, was also dependent on gD-expressing cells for productive replication. Non-complementing cells infected by phenotypically gD-complemented PrV(376) produced non-infectious particles lacking glycoproteins gD and gE as shown by immunoelectron microscopy. Owing to the absence of any homologous sequences between the viral genome and the viral genes resident in the complementing cell line, rescue by homologous recombination was impossible. In cell culture, plaques of PrV(376) were significantly smaller than those of either wild-type, or gD- or gE-deleted mutants, indicating an additive or synergistic effect of the combined deletion on viral cell-to-cell spread capability. Intranasal or intramuscular infection of pigs with phenotypically gD-complemented PrV(376) showed a complete attenuation of viral virulence, with an expected lack of shedding of infectious virus. The PrV(376)-vaccinated pigs exhibited a significant level of protection against challenge infection, measured by survival and weight loss. In summary, PrV(376) represents a novel type of herpesvirus vaccine that combines innocuity, efficacy and biological safety.

Identification and characterization of a novel structural glycoprotein in pseudorabies virus, gL

Herpesvirus envelope glycoproteins play important roles in the interaction between virions and target cells. In the alphaherpesvirus pseudorabies virus (PrV), seven glycoproteins that all constitute homologs of glycoproteins found in herpes simplex virus type 1 (HSV-1) have been characterized, including a homolog of HSV-1 glycoprotein H (gH). Since HSV-1 gH is found associated with another essential glycoprotein, gL, we analyzed whether PrV also encodes a gL homolog. DNA sequence analysis of a corresponding part of the UL region adjacent to the internal inverted repeat in PrV strains Kaplan and Becker revealed the presence of two open reading frames (ORF). Deduced proteins exhibited homology to uracil-DNA glycosylase encoded by HSV-1 ORF UL2 (54% identity) and gL encoded by HSV-1 ORF UL1 (24% identity), respectively. To identify the PrV UL1 protein, rabbit antisera were prepared against two synthetic oligopeptides that were predicted by computer analysis to encompass antigenic epitopes. Sera against both peptides reacted in Western blots of purified virions with a 20-kDa protein. The specificity of the reaction was demonstrated by peptide competition. Since the PrV UL1 sequence did not reveal the presence of a consensus N-linked glycosylation site, concanavalin A affinity chromatography and enzymatic deglycosylation of virion glycoproteins were used to ascertain that the PrV UL1 product is O glycosylated. Therefore, we designated this protein PrV gL. Analysis of mutant PrV virions lacking gH showed that concomitantly with the absence of gH, gL was also missing in purified virions. In summary, we identified and characterized a novel structural PrV glycoprotein, gL, which represents the eighth PrV glycoprotein described. In addition, we show that virion location of PrV gL is dependent on the presence of PrV gH.

Detection of porcine reproductive respiratory syndrome virus by the polymerase chain reaction

A polymerase chain reaction (PCR) is described for the detection of the porcine reproductive respiratory syndrome virus (PRRSV). Using the PCR we were able to detect about 30 infectious units of PRRSV resolved in tissue culture medium or sperm. For the detection of PRRSV in sperm the PCR is 10-times more sensitive than culturing in alveolar macrophages. For the detection of PRRSV, PCR provides a good alternative to cell culture methods.

Molecular characterization of porcine reproductive and respiratory syndrome virus, a member of the arterivirus group

Porcine reproductive and respiratory syndrome virus (PRRSV)-specific cDNA clones spanning the 3' terminal 5 kb of the genomic RNA were isolated, sequenced, and used as probes for identification of PRRSV-specific RNAs. The PRRSV genome is a positive-stranded polyadenylated RNA of about 15 kb. In infected cells, a 3' coterminal nested set of six major subgenomic mRNAs could be demonstrated. Within the 3' terminal 3.5 kb of the PRRSV genome, six overlapping reading frames (ORFs) were identified, each most likely expressed by one of the subgenomic mRNAs. Amino acid sequence comparisons revealed that the most 3' terminal ORF (ORF7) encodes the PRRSV nucleocapsid protein with a calculated molecular weight of 14 kDa. It displays 44.8% amino acid identity with the capsid protein of lactate dehydrogenase-elevating virus (LDV) and 23.6% with that of equine arteritis virus (EAV). The product of ORF6, the second 3' terminal ORF, represents a putative membrane protein and exhibits 53.2 and 27.2% amino acid identity with the corresponding LDV and EAV polypeptides, respectively. Similar to EAV, ORFs 2 through 5 might encode glycosylated viral proteins. The polypeptide deduced from the most 5' ORF (ORF1b) contains two conserved domains common to EAV and coronavirus polymerases. Genome organization, strategy of gene expression, and the sequence of deduced proteins show that PRRSV belongs to the Arterivirus group of viruses.

Identification and characterization of pseudorabies virus glycoprotein H

On the basis of DNA sequence analysis, it has recently been shown that the pseudorabies virus (PrV) genome encodes a protein homologous to glycoprotein H (gH) of other herpesviruses (B. Klupp and T.C. Mettenleiter, Virology 182:732-741, 1991). To obtain antibodies specific for gH(PrV), rabbits were immunized with synthetic peptides representing two potential epitopes on gH(PrV) as predicted by computer analysis. The antipeptide sera recognized the gH precursor polypeptide pgH translated in vitro from an in vitro-transcribed mRNA. Western blot (immunoblot) analyses of purified pseudorabies virions using these antisera revealed specific reactivity with a protein with an apparent molecular mass of 95 kDa. Specificity of the reaction could be demonstrated by competition experiments with respective peptides. Analysis of PrV deletion mutants defective in genes encoding known glycoproteins proved that gH(PrV) constitutes a novel PrV glycoprotein not previously found. Treatment of purified virion preparations with endoglycosidase H reduced the apparent molecular mass of gH(PrV) to 90 kDa, indicating the presence of N-linked high-mannose (or hybrid) carbohydrates in mature virions. Removal of all N-linked carbohydrates by N-glycosidase F resulted in a product of 76 kDa. In summary, our results demonstrate the existence of gH in PrV as a structural component of the virion.

Pseudorabies virus glycoprotein gI: in vitro and in vivo analysis of immunorelevant epitopes

Overlapping fragments of the gene encoding glycoprotein gI of pseudorabies virus (PRV; herpesvirus suis 1) were expressed in bacteria. Using the fusion proteins and a panel of monoclonal antibodies (MAbs) against gI as well as swine sera we found that the N-terminal part of gI (residues 33 to approximately 100) contains a highly antigenic and immunogenic domain. Transfer of antibodies binding to this region as well as vaccination with fusion proteins containing the N terminus of gI are able to confer protection to mice against a lethal challenge of virus. The results show that gI, which is non-essential for virus replication in tissue culture, can induce neutralizing and protective antibodies. The potential suitability of fusion proteins encompassing N-terminal parts of gI as diagnostic tools is demonstrated.

Records, recall loss, and recall bias in pregnancy: a comparison of interview and medical records data of pregnant and postnatal women

To determine the agreement between interview-based and medical records data concerning illnesses and medications early in pregnancy, we compared the interviews of 202 women with the ongoing records collected during their pregnancies. Substantial underrecording of most transient illnesses was found. Fewer short-term illnesses were reported by postpartum women than sill-pregnant women, suggesting the potential for recall bias or loss.

Innocuity testing of foot-and-mouth disease vaccines. I. Formaldehyde-inactivated alhydrogel vaccines

Conditions that contribute to efficient innocuity testing of formaldehyde (FA)-inactivated alhydrogel vaccines were investigated. Under our conditions good yields of 146S antigen were obtained if the antigen was eluted by potassium phosphate buffer (pH 7.4) and concentrated by ultrafiltration. Non-inactivated virus added to the vaccine and adsorbed overnight could be recovered if residual FA was removed from the vaccine by washing the gel thoroughly with Frenkel culture medium before the addition of the virus. It was shown that the presence of high concentrations of inactivated virus in the concentrated eluate could prevent the detection of small amounts infectious virus in intradermolingual tests in cattle. This interference phenomenon was not found if (more susceptible) monolayers of foetal calf thyroid cells were used for the detection of virus. Intensive pre-washing of the gel with Frenkel culture medium, elution with potassium phosphate, concentration by ultrafiltration and the use of thyroid cells for the final detection of surviving virus is therefore advised for safety testing.

Subcellular compartmentation of glycolytic intermediates in Trypanosoma brucei

In cell-fractionation experiments most of the glycolytic enzymes in bloodstream forms of Trypanosoma brucei are recovered in a microbody, called the glycosome [Opperdoes, F. R. and Borst, P. (1977) FEBS Lett. 80, 360-364]. To see whether this compartmentation of glycolytic enzymes is accompanied by compartmentation of metabolites we have pulse-labelled intact T. brucei with [U-14C]glucose and followed the incorporation of radioactivity into glycolytic intermediates separated by anion-exchange chromatography. The kinetics of incorporation provide direct evidence for the existence of two pools of glycolytic intermediates. One pool is completely labelled within 15 s and represents 20-30% of total cellular metabolites. Radioactively labelled pyruvate is already produced after 15 s. Since this pool is directly involved in the glycolytic flux, we conclude that it is present in the glycosome. The second pool which represents 70-80% of the total appears not to be directly involved in glycolysis. Its content equilibrates relatively slowly with the glycosomal pool. It probably represents the cytosol. Incorporation of radioactivity into the total glycerol 3-phosphate pool is more rapid than for the other metabolites studied. This indicates rapid mixing of the glycosomal and cell-sap pools of glycerol 3-phosphate, as required for the extra-glycosomal oxidation of glycerol 3-phosphate by the mitochondrial oxidase. In the presence of 1 mM salicylhydroxamic acid, which mimics anaerobiosis, the trypanosome produces equimolar amounts of pyruvate and glycerol. Labelling of glycerol and glycerol 3-phosphate proceeds at identical rates but at all times the specific activity of glycerol is less than that of glycerol 3-phosphate. This is compatible with our earlier proposal that glycerol is made from glycerol 3-phosphate by glycerol kinase. We conclude that glycolysis in trypanosomes takes place in the glycosome and that the membrane of this organelle is poorly permeable to most glycolytic intermediates.

Glycolysis in Trypanosoma brucei

The possibility that the glycosomes present in the bloodstream form of Trypanosoma brucei [Opperdoes, F. R. and Borst, P. (1977) FEBS Lett. 80, 360--364] constitute a separate pool of glycolytic intermediates within the cell was investigated. In titrations of intact cells with digitonin, a differential activation of glycolytic enzymes was observed. Enolase, pyruvate kinase and the cell-sap marker alanine aminotransferase were activated at 0.05 mg digitonin per mg protein. The nine glycosomal enzymes involved in the conversion of glucose and glycerol into 3-phosphoglycerate were activated only at digitonin concentrations between 0.7 and 9.8 mg/mg protein. In subcellular fractions the activities of the latter enzymes were all latent between 70 and 92%. Latency was abolished by addition of 0.1% Triton X-100 or partly by five cycles of freezing and thawing. We conclude that the glycosomal enzymes are surrounded by a membrane, which forms a permeability barrier to intermediates and co-factors of glycolysis. The concentrations of glycolytic intermediates and of adenine nucleotides were measured under aerobic conditions as well as in the presence of 1 mM salicylhydroxamic acid, a respiratory inhibitor. Addition of salicylhydroxamic acid caused the following changes: (a) The levels of almost all glycolytic intermediates measured decreased. Glycerol-3-phosphate, however, increased fourfold. (b) The phosphate potential was drastically lowered from 2900 to 450 M-1. (c) The trypanosomes became more reduced, as monitored by a change in the apparent redox state of the NADH/NAD+ courple from E'h = -189 to E'h = -219 mV. From the high levels of metabolite concentrations found and from comparison of the apparent mass-action ratios calculated for the separate glycolytic reactions with those for other organisms, we conclude that in bloodstream form T. brucei the glycolytic intermediates are present in the glycosomes as well as in the cytosol and that the two pools of intermediates equilibrate with each other, despite the presence of the glycosomal membrane.