SM Strain Research Articles

Neonatal lethality of mouse A/J-7SM consomic strain is caused by an insertion mutation in the Dchs1 gene.

Homosomic mice of the A/J-7SM consomic mouse strain that introduced the entire chromosome 7 (Chr 7) of SM/J into the A/J strain exhibited neonatal lethality. We tentatively maintained segregating inbred strains (A/J-7ASM and A/J-7DSM) in which the central portion of Chr 7 was heterozygous for the A/J and SM/J strains, and the centromeric and telomeric sides of Chr 7 were homozygous for the SM/J strain, instead of the A/J-7SM strain. Based on the chromosomal constitution of Chr 7 in A/J-7ASM and A/J-7DSM mice, the causative gene for neonatal lethality in homosomic mice was suggested to be located within an approximately 1.620Mb region between D7Mit125 (104.879Mb) and D7Mit355 (106.499Mb) on Chr 7. RT-PCR analysis revealed that homosomic mice lacked dachsous cadherin-related 1 (Dchs1), which is located within the D7Mit125 to D7Mit355 region and functions in the regulation of planar cell polarity. Screening for mutations in Dchs1 indicated that homosomic mice possessed an early transposable (ETn)-like sequence in intron 1 of Dchs1. Moreover, an allelism test between Dchs1 ETn-like-insertion alleles detected in homosomic mice and CRISPR/Cas9-induced Dchs1 deletion alleles revealed that Dchs1 is a causative gene for neonatal lethality in homosomic mice. Based on these results, we concluded that in the A/J-7SM strain, ETn-like elements were inserted into intron 1 of SM/J-derived Dchs1 during strain development, which dramatically reduced Dchs1 expression, thus resulting in neonatal lethality in homosomic mice. Additionally, it was suggested that the timing of lethality in Dchs1 mutant mice is influenced by the genetic background.

Left atrial strain can predict right ventricular impairment and developement of atrial fibrilation in patients with severe mitral stenosis better than transmitral gradients

Abstract Funding Acknowledgements Type of funding sources: None. Introduction. Rheumatic heart disease is a major health problem in developing countries and remains the leading cause of mitral valve stenosis (MS) and valve replacement in adults. Left atrial (LA) inflammation due to rheumatic carditis, pressure overload because of mitral stenosis, lead to fibrosis and remodeling to progressive lost of LA reservoir/compliant capacity that might be responsible of the pressure backward load to the pulmonary circulation. The aims of the study were to determine if 1) there is any correlation between LA strain parameters with pulmonary systolic arterial pressure (PASP) and other parameters related with pulmonary pressure and right ventricular (RV) function and 2) if LA strain can better identify those patients who developed atrial fibrilation (AF). Methods. Strain of the LA was measured in 101 patients retrospectively enrolled with severe MS using two dimensional speckle tracking (2DSTE). Sixty of them were in sinus rhythm (SR) and 40 in atrial fibrillation (AF). The LA 2DSTE was measured from the 4 chamber view of 2 consecutive cycles at expiration and offline evaluated. Based on the QRS onset, the positive peak strain curve was defined as LA end systolic strain. The end of the reservoir phase was defined as 1 frame before mitral valve opening (LA- RES). When the patient was in SR, immediately after the P wave, LA contractile function was identified (LA-booster). Strain of the free wall and global RV was measured in 4CH. A standard echocardiographic assessment was done in accordance with the recommendation of the American Society of Echocardiography. Results. Patients mean age was 47.4 ± 11.9 years, 30 males and 71 females. Mean gradient across the mitral valve (MV) was 8.3 ± 5.1 mmHg and the MV area derived by pressure half time was 1.3 ± 0.3 cm2, LVEF was 51.79 ± 11.3%. Right ventricular (RV) function parameters were TAPSE 19.6 ± 5.2 mm, S` 10.5 ± 2.5 cm/s, RV fraction area change 35.6 ± 9.1% and RV free wall peak strain – 17.96 ± 6.5%. LVMi 51.79 ± 11.3 gr/m2, SVi 34.6 ± 10.3 ml/m2. LA-RES 11.18 ± 3.7%, LA volume in systole 128.3 ± 48.3 ml, LAEF 20.1 ± 12.5%. The group was divided according to tertiles of LA-RES (group 1, 33 patients, strain was < =7%, group 2, 32 patients with strain between 8 and 13%, group 3, 32 patients, strain > =14%). There was a decrease in PASP (group 1, 42.3 ± 17.8 mmHg; group 2, 38.3 ± 17.9 mmHg; group 3, 31.6 ± 17.9 mmHg, p =0.028) and PVR (group 1, 2.5 ± 1; group 2, 2.0 ± 0.6; group 3, 1.6 ± 0.4, p< 0.0001) as LA-RES increased. RV function represented by TAPSE, Sm, RVFAC and RV free wall strain significantly increased as LA-RES increased. The area under the ROC curve was calculated for LA-RES, MV mean gradient, MV area derived by PHT and LA systolic volume as a predictors of AF. LA-RES was the one that better predicted the presence of AF. Conclusion. In severe MS, LA-RES was able to better identify those with higher PASP and worst RV function. Moreover LA-RES was also able to better predict those patients who developed AF.

Does Saving Cause Borrowing?

We study whether savings nudges have the unintended consequence of additional borrowing in high-interest credit. We use data from a pre-registered experiment that encouraged 3.1 million bank customers to save via SMS messages and train a machine learning algorithm to predict individual-level treatment effects. We then focus on individuals who are predicted to save most in response to the intervention and hold credit card debt. We find that these individuals save 5.7% more (61.84 USD per month) but do not change their borrowing: for every additional dollar saved, we can rule out increases of more than two cents in interest expenses.

Comparison of the Pathogenicity of Classical Swine Fever Virus Subgenotype 2.1c and 2.1d Strains from China

Classical swine fever (CSF) caused by classical swine fever virus (CSFV) is a highly contagious and devastating disease. The traditional live attenuated C-strain vaccine is widely used to control disease outbreaks in China. Since 2000, subgenotype 2.1 has become dominant in China. Here, we isolated subgenotype 2.1c and 2.1d strains from CSF-suspected pigs. The genetic variations and pathogenesis of subgenotype 2.1c and 2.1d strains were investigated experimentally. We aimed to evaluate and compare the replication characteristics and clinical signs of subgenotype 2.1c and 2.1d strains with those of the typical highly virulent CSFV SM strain. In PK-15 cells, the three CSFV isolates exhibited similar replication levels but significantly lower replication levels compared with the CSFV SM strain. The experimental animal infection model showed that the pathogenicity of subgenotype 2.1c and 2.1d strains was less than that of the CSFV SM strain. According to the clinical scoring system, subgenotype 2.1c (GDGZ-2019) and 2.1d (HBXY-2019 and GXGG-2019) strains were moderately virulent. This study showed that the pathogenicity of CSFV field strains will aid in the understanding of CSFV biological characteristics and the related epidemiology.

Thirty Mouse Strain Survey of Voluntary Physical Activity and Energy Expenditure: Influence of Strain, Sex and Day-Night Variation.

We measured indirect calorimetry and activity parameters, VO2 and VCO2 to extract respiratory exchange ratio (RER) and energy expenditure in both sexes of 30 inbred mouse strains of 6 genetic families at 9–13 weeks during one photophase and the subsequent scotophase. We observed a continuous distribution of all traits. While males had higher body weights than females, we observed no sex difference for food and water intake. All strains drank and fed more during the night even if they displayed no day–night difference in activity traits. Several strains showed absent or weak day–night variation in one or more activity traits and these included FVB and 129X1, males of 129S1, SWR, NZW, and SM, and females of SJL. In general females showed higher rearing and ambulatory activity with 6 and 9 strains, respectively, showing a sex difference. Fine motor movements, like grooming, showed less sex differences. RER underlied a strong day–night difference and no sex effect. Only FVB females and males of the RIIIS and SM strain had no day–night variation. Energy expenditure underlies a large day–night variation which was absent in SWR and in FVB females and RIIIS males. In general, female bodies had a tendency to higher energy expenditure values, which became a significant difference in C3H, MAMy, SM, DBA1, and BUB. Our data illustrate the diversity of these traits in male and female inbred mice and provide a resource in the selection of strains for future studies.

Detection of 5 Kinds of Genes Related to Plasmid-Mediated Quinolone Resistance in Four Species of Nonfermenting Bacteria with 2 Drug Resistant Phenotypes.

Objective This study aimed to detect 5 kinds of genes related to plasmid-mediated quinolone resistance in four species of nonfermenting bacteria with 2 drug resistance phenotypes (multidrug resistance and pandrug resistance), which were Acinetobacter baumannii (Ab), Pseudomonas aeruginosa (Pa), Stenotrophomonas maltophilia (Sm), and Elizabethkingia meningoseptica (Em). Methods The Phoenix NMIC/ID-109 panel and API 20NE panel were applied to 19 isolated strains, including 6 Ab strains (2 strains with multidrug resistance and 4 strains with pandrug resistance), 6 Pa strains (3 strains with multidrug resistance and 3 strains with pandrug resistance), 4 Sm strains (2 strains with multidrug resistance and 2 strains with pandrug resistance), and 3 Cm strains (2 strains with multidrug resistance and 1 strain with pandrug resistance). After strain identification and drug susceptibility test, PCR was applied to detect 5 genes related to plasmid-mediated quinolone resistance. The genes detected were quinolone resistance A (qnrA), aminoglycoside acetyltransferase ciprofloxacin resistance variant, acc(6′)-Ib-cr, and 3 integrons (intI1, intI2, and intI3). The amplified products were analyzed by 1% agarose gel electrophoresis and sequenced. Sequence alignment was carried out using the bioinformatics technique. Results Of 19 strains tested, 8 strains carried acc(6′)-Ib-cr and 6 of them were of pandrug resistance phenotype (3 Ab strains, 2 Pa strains, and 1 Sm strain). The carrying rate of acc(6′)-Ib-cr was 60.0% for strains of pandrug resistance (6/10). Two strains were of multidrug resistance (1 Ab strain and 1 Pa strain), and the carrying rate of acc(6′)-Ib-cr was 22.0% (2/9). The carrying rate was significantly different between strains of multidrug resistance and pandrug resistance (P < 0.05). The class 1 integron was detected in 11 strains, among which 6 strains were of pandrug resistance (3 Ab strains, 2 Pa strains, and 1 Sm strain). The carrying rate of the class 1 integron was 60.0% (6/10). Five strains were of multidrug resistance (3 Pa strains, 1 Ab strain, and 1 Em strain), and the carrying rate was 55.6% (5/9). The carrying rate of the class 1 integron was not significantly different between strains of multidrug resistance and pandrug resistance (P > 0.05). Both acc(6′)-Ib-cr and intI1 were detected in 6 strains, which were negative for qnrA, intI2, and intI3. Conclusion Quinolone resistance of isolated strains was related to acc(6′)-Ib-cr and intI1 but not to qnrA, intI2, or intI3. The carrying rate of acc(6′)-Ib-cr among the strains of pandrug resistance was much higher than that among the strains of multidrug resistance. But, the strains of two drug resistant phenotypes were not significantly different in the carrying rate of intI1. The detection rates of the two genes were high and similar in Ab and Pa strains. 1 Em strain carried the class 1 integron.

Congenic mapping and candidate gene analysis for streptozotocin-induced diabetes susceptibility locus on mouse chromosome 11.

Streptozotocin (STZ) has been widely used to induce diabetes in rodents. Strain-dependent variation in susceptibility to STZ has been reported; however, the gene(s) responsible for STZ susceptibility has not been identified. Here, we utilized the A/J-11SM consomic strain and a set of chromosome 11 (Chr. 11) congenic strains developed from A/J-11SM to identify a candidate STZ-induced diabetes susceptibility gene. The A/J strain exhibited significantly higher susceptibility to STZ-induced diabetes than the A/J-11SM strain, confirming the existence of a susceptibility locus on Chr. 11. We named this locus Stzds1 (STZ-induced diabetes susceptibility 1). Congenic mapping using the Chr. 11 congenic strains indicated that the Stzds1 locus was located between D11Mit163 (27.72Mb) and D11Mit51 (36.39Mb). The Mpg gene, which encodes N-methylpurine DNA glycosylase (MPG), a ubiquitous DNA repair enzyme responsible for the removal of alkylated base lesions in DNA, is located within the Stzds1 region. There is a close relationship between DNA alkylation at an early stage of STZ action and the function of MPG. A Sanger sequence analysis of the Mpg gene revealed five polymorphic sites in the A/J genome. One variant, p.Ala132Ser, was located in a highly conserved region among rodent species and in the minimal region for retained enzyme activity of MPG. It is likely that structural alteration of MPG caused by the p.Ala132Ser mutation elicits increased recognition and excision of alkylated base lesions in DNA by STZ.

Detection of cardiomyopathy in children with Marfan Syndrome with 2D strain echocardiography

Studies have found cardiomyopathy in adult patients with marfan syndrome (MS) with systolic dysfunction. Sophisticated techniques such as 2D strain echocardiography or “speckle tracking imaging” (STI) have been reported to detect early cardiac dysfunction and to be more accurately. The aim of our study was to evaluate the validity of STI for the study of myocardial function in children with MS, and to assess the interest for cardiomyopathy detection in this population. Echocardiographic parameters of left ventricular systolic function were compared between two populations in standard 2D, STI and cardiac MRI. We included 39 MS (clinically confirmed from the 2010 modified criteria of Ghent or genetically with mutations on the FBN1 gene) and 41 healthy children, aged 4 to 18 years old (respectively mean ± age SD 12.07 ± 4.81 and 11.82 ± 3.64). They were paired on the body surface. The values of global strain longitudinal peak (SLG) of MS were compared with values of ejection fraction of the left ventricle (LVEF) assessed by cardiac MRI (gold standard). Relations between the two types of mutations (PTC and inframe) in SM and altered strain were studied. Impaired SLG was significant for 7 segments: basal inferoseptal ( P = 0.0001), mid anterolateral ( P = 0.0083), basal anterolateral ( P < 0.0001), basal inferior ( P = 0.0057), apical lateral ( P = 0.0084), basal anterior ( P < 0.0001) and basal inferolateral ( P = 0.0103). This segmental impairment predominated the basal level with apex-to-base gradient. Patients with more altered SLG appeared to have a greater dilatation of the ascending aorta ( P = 0.03). This study is the largest pediatric cohort who compare 2D strain echocardiography and MRI in children with SM. The interest for primary or secondary cardiomyopathy detection remains to be validated and consolidated with larger studies and could justify not only to focus on the aorta.

Isolation of cariogenic Streptococcus mutans and the inhibitory effect of egg yolk antibody on caries

Objective: To isolate the cariogenic Streptococcus mutans (Sm) strains and study the therapeutical effect of egg yolk antibody (IgY) of the Sm on dental caries development. Methods: Sm strains were isolated from the children's dental plaque samples. Morphological, biochemical and molecular biological methods were applied to identify the serotype, acid producing and adhesion abilities of isolated Sm strains. After inactivation one of the Sm strains was used as antigen to immune laying hens to collect and extract the specific anti-Sm IgY. The rats were infected with Sm (serotype e). After 16 weeks of infection, all the rats were found developing dental caries. The rats were then randomly divided into two groups. The rats in experimental group were supplied with diet containing anti-Sm IgY while the rats in control group with normal IgY. All rats were sacrificed after another 8 weeks' observation. The degree of caries for each rat was assessed using Keyes' method. Results: We isolated 7 Sm strains from the children's dental plaque samples in the present study. The numbers of serotype c, e, f, k were 3, 2, 0 and 2, respectively. All strains showed similar morphological and biochemical characters as standard UA159 Sm strain, and possessed strong capabilities of acid production and adherence. Interestingly, even the same serotypec strains, such as No.3 and No.7 strains, demonstrated significant difference on acid producing and adherence capabilities. After 16 weeks infection with serotype e strain, the rats' mandibular teeth were apparently decayed, and treatment with specific anti-Sm IgY obviously attenuated the development of caries in the experiment group rats (16.4±2.0) compared with that in the control group rats (30.2±9.3) (P<0.05) determined by Keyes' method. Conclusions: Seven cariogenic Sm strains of different serotypes were isolated, which possesses similar morphology and biochemical characters. Although belonging to the same serotype strains they always show significant difference in acid-producing and adherencec apabilities. Further experiment provides evidences that the serotype e strain could obviously induce caries independently, and employment of specific anti-Sm IgY as passive immunotherapy additive might effectively inhibit the further development of dental caries.

Thermotolerance, oxidative stress, apoptosis, heat-shock proteins and damages to reproductive cells of insecticide-susceptible and -resistant strains of the diamondback moth Plutella xylostella.

In this study, we investigated thermotolerance, several physiological responses and damage to reproductive cells in chlorpyrifos-resistant (Rc) and -susceptible (Sm) strains of the diamondback moth, Plutella xylostella subjected to heat stress. The chlorpyrifos resistance of these strains was mediated by a modified acetylcholinesterase encoded by an allele, ace1R, of the ace1 gene. Adults of the Rc strain were less heat resistant than those of the Sm strain; they also had lower levels of enzymatic activity against oxidative damage, higher reactive oxygen species contents, weaker upregulation of two heat shock protein (hsp) genes (hsp69s and hsp20), and stronger upregulation of two apoptotic genes (caspase-7 and -9). The damage to sperm and ovary cells was greater in Rc adults than in Sm adults and was temperature sensitive. The lower fitness of the resistant strain, compared with the susceptible strain, is probably due to higher levels of oxidative stress and apoptosis, which also have deleterious effects on several life history traits. The greater injury observed in conditions of heat stress may be due to both the stronger upregulation of caspase genes and weaker upregulation of hsp genes in resistant than in susceptible individuals.

Proteomic and metabolomic analyses reveal metabolic responses to 3-hydroxypropionic acid synthesized internally in cyanobacterium Synechocystis sp. PCC 6803.

Background3-hydroxypropionic acid (3-HP) is an important platform chemical with a wide range of applications. In our previous study, the biosynthetic pathway of 3-HP was constructed and optimized in cyanobacterium Synechocystis sp. PCC 6803, which led to 3-HP production directly from CO2 at a level of 837.18 mg L−1 (348.8 mg/g dry cell weight). As the production and accumulation of 3-HP in cells affect cellular metabolism, a better understanding of cellular responses to 3-HP synthesized internally in Synechocystis will be important for further increasing 3-HP productivity in cyanobacterial chassis.ResultsUsing a engineered 3-HP-producing SM strain, in this study, the cellular responses to 3-HP internally produced were first determined using a quantitative iTRAQ-LC–MS/MS proteomics approach and a LC–MS-based targeted metabolomics. A total of 2264 unique proteins were identified, which represented about 63 % of all predicted protein in Synechocystis in the proteomic analysis; meanwhile intracellular abundance of 24 key metabolites was determined by a comparative metabolomic analysis of the 3-HP-producing strain SM and wild type. Among all identified proteins, 204 proteins were found up-regulated and 123 proteins were found down-regulated, respectively. The proteins related to oxidative phosphorylation, photosynthesis, ribosome, central carbon metabolism, two-component systems and ABC-type transporters were up-regulated, along with the abundance of 14 metabolites related to central metabolism. The results suggested that the supply of ATP and NADPH was increased significantly, and the precursor malonyl-CoA and acetyl-CoA may also be supplemented when 3-HP was produced at a high level in Synechocystis. Confirmation of proteomic and metabolomic results with RT-qPCR and gene-overexpression strains of selected genes was also conducted, and the overexpression of three transporter genes putatively involved in cobalt/nickel, manganese and phosphate transporting (i.e., sll0385, sll1598 and sll0679) could lead to an increased 3-HP production in Synechocystis.ConclusionsThe integrative analysis of up-regulated proteome and metabolome data showed that to ensure the high-efficient production of 3-HP and the normal growth of Synechocystis, multiple aspects of cells metabolism including energy, reducing power supply, central carbon metabolism, the stress responses and protein synthesis were enhanced in Synechocystis. The study provides an important basis for further engineering cyanobacteria for high 3-HP production.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0627-6) contains supplementary material, which is available to authorized users.

Multistate Outbreak of Serratia marcescens Bloodstream Infections Caused by Contamination of Prefilled Heparin and Isotonic Sodium Chloride Solution Syringes

To investigate clusters of Serratia marcescens (SM) bloodstream infections (BSIs) at health care facilities in several states and determine whether contaminated prefilled heparin and isotonic sodium chloride solution (hereinafter, saline) syringes from a single manufacturer (company X) were the likely cause, we performed an outbreak investigation of inpatient and outpatient health care facilities from October 2007 through February 2008. Active case finding for clusters of SM BSIs. Information on SM BSIs was obtained, and SM blood isolates were sent to the Centers for Disease Control and Prevention (CDC). Culture specimens were taken from various lots of prefilled heparin and saline syringes by health care facilities and the CDC to test for the presence of SM. The SM isolates from syringes and blood were compared by pulsed-field gel electrophoresis. A total of 162 SM BSIs in 9 states were reported among patients at facilities using prefilled heparin and/or saline syringes made by company X. Cultures of unopened prefilled heparin and saline syringes manufactured by company X grew SM. Of 83 SM blood isolates submitted to the CDC from 7 states, 70 (84%) were genetically related to the SM strain isolated from prefilled syringes. A US Food and Drug Administration inspection revealed that company X was not in compliance with quality system regulations. A multistate outbreak of SM BSIs was associated with intrinsic contamination of prefilled syringes. Our investigation highlights important issues in medication safety, including (1) the importance of pursuing possible product-associated outbreaks suggested by strong epidemiologic data even when initial cultures of the suspected product show no contamination and (2) the challenges of medical product recalls when production has been outsourced from one company to another.

Negative Regulation of the Yeast ABC Transporter Ycf1p by Phosphorylation within Its N-terminal Extension

The yeast vacuolar membrane protein Ycf1p and its mammalian counterpart, MRP1, belong to the ABCC subfamily of ATP-binding cassette (ABC) transporters that rid cells of toxic endogenous and xenobiotic compounds. Like most members of the ABCC subfamily, Ycf1p contains an N-terminal extension in addition to its ABC "core" domain and transports substrates in the form of glutathione conjugates. Ycf1p is subject to complex regulation to ensure its optimal function. Previous studies showed that Ycf1p activity is stimulated by a guanine nucleotide exchange factor, Tus1p, and is positively regulated by phosphorylation in its ABC core domain at residues Ser-908 and Thr-911. Here we provide evidence that phosphorylation of Ser-251 in the Ycf1p N-terminal extension negatively regulates activity. Mutant Ycf1p-S251A exhibits increased resistance to cadmium in vivo and increased Ycf1p-dependent transport of [(3)H]estradiol-beta-17-glucuronide in vitro as compared with wild-type Ycf1p. Activity is restored to the wild-type level for Ycf1-S251E. To identify kinase(s) that negatively regulate Ycf1p function, we conducted an integrated membrane yeast two-hybrid (iMYTH) screen and identified two kinase genes, CKA1 and HAL5, deletion of which increases Ycf1p function. Genetic evidence suggests that Cka1p may regulate Ycf1p function through phosphorylation of Ser-251 either directly or indirectly. Overall, this study provides compelling evidence that negative, as well as positive, regulation of Ycf1p is mediated by phosphorylation.

Alterations of Left Ventricular Myocardial Characteristics Associated With Obesity

Obesity is associated with heart failure, but an effect of weight, independent of comorbidities, on cardiac structure and function is not well established. We sought whether body mass index (BMI) and insulin levels were associated with subclinical myocardial disturbances. Transthoracic echocardiography, myocardial Doppler-derived systolic (sm) and early diastolic velocity (em), strain and strain rate imaging and tissue characterization with cyclic variation (CVIB), and calibrated integrated backscatter (cIB) were obtained in 109 overweight or obese subjects and 33 referents (BMI <25 kg/m2). BMI correlated with left ventricular (LV) mass and wall thickness (P<0.001). Severely obese subjects (BMI >35) had reduced LV systolic and diastolic function and increased myocardial reflectivity compared with referents, evidenced by lower average long-axis strain, sm, cIB, lower CVIB, and reduced em, whereas LV ejection fraction remained normal. Differences in regional or global strain, sm, and em were identified between the severely obese (BMI >35) and the referent patients (P<0.001). Similar but lesser degrees of reduced function by sm, em, and basal septal strain and increased reflectivity by cIB were present in overweight (BMI, 25 to 29.9) and mildly obese (BMI, 30 to 35) groups (P<0.05). Although tissue Doppler measures were not associated with duration of obesity, they did correlate with fasting insulin levels and reduced exercise capacity. BMI was independently related to average LV strain (beta=0.40, P=0.02), sm (beta=-0.36, P=0.002), and em (beta=-0.41, P<0.001). Overweight subjects without overt heart disease have subclinical changes of LV structure and function even after adjustment for mean arterial pressure, age, gender, and LV mass.

The effect of genotype on sensitivity to electroacupuncture analgesia

Individual differences in sensitivity to pain and analgesia are well appreciated, and increasing evidence has pointed towards a role of inherited genetic factors in explaining some proportion of such variability. It has long been known by practitioners of acupuncture, an ancient modality of analgesia, that some patients are ‘responders’ and others ‘non-responders.’ The present research was aimed at defining the inherited genetic influence on acupuncture analgesia in the mouse, using 10 common inbred strains. Two pairs of metallic needles were inserted into acupoints ST 36 and SP 6, fixed in situ and then connected to the output channel of an electric pulse generator. Electroacupuncture (EA) parameters were set as constant current output (intensity: 1.0–1.5–2.0 mA, 10 min each; frequency: 2 or 100 Hz) with alteration of a positive and negative square wave, 0.3 ms in pulse width. Tail-flick latencies evoked by radiant heat were measured before, during and after EA stimulation. Narrow-sense heritability estimates of 2 and 100 Hz EA were 0.37 and 0.16, respectively. We found that the C57BL/10 strain was the most sensitive, and the SM strain was the least sensitive to both 2 and 100 Hz EA. However, the relative sensitivities of other strains to these two EA frequencies suggested some genetic dissociation between them as well. These results demonstrate a role of inherited genetic factors in EA sensitivity in the mouse, although the low-to-moderate heritability estimates suggest that environmental factors may be of greater importance in predicting who will benefit from this analgesic modality.

Parasite and vertebrate host genetic heterogeneity determine the outcome of infection by Schistosoma mansoni.

Intraspecific variation in Schistosoma mansoni infection and modulation of its expression by vertebrate host genetics was studied by evaluation of some biological parameters of the infection in BALB/c and C57BL/6 mice infected with one Brazilian (BH) and two Venezuelan (YT and SM) laboratory strains of the parasite. Mice infected with 60 cercariae of each parasite strain were euthanized at 5, 6, 8, and 12 weeks. Parameters recorded included the number of adult worms recovered by portal perfusion (infectivity); the number of eggs in the feces, the intestine, and the liver; and the ability of the eggs to cross the intestine, expressed as a quotient of the number of eggs in the intestine versus the feces. Results showed that the parasite appeared to determine the infectivity, the sex ratio, the onset and timing of oviposition, the number of eggs produced, initial egg laying toward the liver, and the ability to cross the intestinal wall. In this sense the BH strain appeared to be the most efficient and the SM strain, the most delayed; the YT strain was intermediate, although closer to the SM strain. On the other hand, the host appeared to influence the susceptibility to infection, the fecundity, and the percentage of eggs distributed in the liver and in the intestine during the chronic stage. In this sense, although they have been shown to be less susceptible to infection than BALB/c mice, C57BL/6 mice permit more eggs to be produced and exhibit similar numbers of eggs in the intestine and the liver at certain time points. It appears from these results that parasite genetics is essential for the outcome of infection with S. mansoni, but some characteristics may be quantitatively modulated by host genetics.

Isolation of Sooty Mangabey Simian T-Cell Leukemia Virus Type I [STLV-I(sm)] and Characterization of a Mangabey T-Cell Line Coinfected with STLV-I(sm) and Simian Immunodeficiency Virus SIVsmmPBj14

It has been postulated that dual infections of humans with human immunodeficiency virus (HIV) and human T-cell leukemia/lymphotropic virus (HTLV) may potentiate disease progression. Counterparts of both of these pathogenic human retroviruses have been identified in various simian species indigenous to Asia and Africa, including sooty mangabey monkeys (Cercocebus atys). Using peripheral blood mononuclear cells (PBMC) from a mangabey naturally infected with both SIV and STLV-I, T-cell lines were established and maintained continuously for more than 3 years; these cell lines harbored only a newly identified mangabey STLV-I(sm) or both STLV-I(sm) and the acutely lethal variant SIVsmmPBj14. The dually infected cell line (FEd-P14) was established byde novoinfection of mangabey PBMC with SIVsmmPBj14. This cell line was characterized by multiple assays which showed that structural proteins encoded by both viruses were produced in large quantities, but that the predominant viral glycoprotein on the cell surface was the STLV-I(sm) Env. Unusual interactions of the two retroviral glycoproteins were suggested by the formation of syncytia between Raji and the FEd-P14 cells, but not between Raji and simian cells infected with only one retrovirus or human cells infected with HTLV-I. The STLV-I(sm) strain obtained from the sooty mangabey was transmitted to normal macaque and mangabey PBMC and was shown to be unique by sequencing of the entireenvgene. STLV-I(sm) from this African species was more closely related to “cosmopolitan” HTLV-I strains than to the prototypic STLV-I from an Asian pig-tailed macaque.In vitroandin vivostudies of STLV-I(sm) and SIVsmm, both isolated from a naturally infected mangabey monkey, may provide insight into disease induction and manifestations associated with coinfection by their human counterparts.

Impaired yolk protein uptake by oocytes of a Bombyx mori mutant

A spontaneous mutant of silkworms which produces small eggs is designated sm. To clarify the function of the sm gene, we examined the biosynthesis and distribution of three major yolk proteins, vitellogenin, 30K protein and egg specific protein. The concentration of protein in hemolymph in sm female pupae was higher than normal in the last half of the pupal stage. The 30K protein concentration in the hemolymph of the sm strain was above normal throughout the pupal stage. Vitellogenin in hemolymph was similarly elevated above normal, especially in the last half of the normal stage. However, sm ovaries, beginning with the fourth day of the pupal stage had lower than normal concentrations of these two proteins together with egg specific protein. These results suggest that while sm fat bodies produced and secreted vitellogenin and 30K protein, the sm ovaries had an impaired uptake of proteins. This abnormality might be caused by gaps between follicle cells, impaired protein receptors, or some other abnormality of follicle cells. In the sm mutant, the egg specific protein gene which is expressed only in follicle cells, was transcribed and translated normally in the follicle cells, but did not attain normal concentrations in the oocytes. The in situ hybridization experiments showed that mRNA of egg specific protein was dispersed throughout sm follicle cells, while in normal cells the signals were located on the side of the follicle cells facing the oocyte. The oocytes of the sm strain have impaired uptake of proteins from both hemolymph and follicle cells.

A new mutant at the Dystrophia muscularis (dy) locus in the SM strain of mice.

Muscular dystrophy was found in the SM strain of mice. This defect was shown to be caused by a single autosomal recessive gene allelic with the genes at the dy locus. The dystrophic SM mice may provide a useful animal model for human muscular dystrophy, because SM strain has been selected for small body size and carries rare alleles at several loci.

Effect of age on ultrastructural changes of cortisone treated mouse hepatic cells

Age differences in the cortisone induced changes of mouse hepatic cell mitochondria and microbodies and in the recovery process were studied electron-microscopically and ultracytochemically, using female mice of SM strain of different ages. In the young and old mice, the mitochondria decreased in number and increased in size by cortisone treatment, more markedly in the old. In the middle aged, though the mitochondria were decreased in number, they did not significantly increase in size. The cytochrome c oxidase activity was demonstrated ultracytochemically in the membrane system of the enlarged mitochondria in all aged groups. Microbodies were observed to be rather increased in number 9th day after treatment, earlier in the old. The mechanism of the increase in mitochondrial volume and cooperation between mitochondria and microbodies is discussed. The organelles of the hepatic cells of the old and young aged, especially of the old, may be considered to have a more limited reserve capacity compared with those of the adult.