NN Genotype Research Articles

Distribution of urinary hippuric acid concentrations by ALDH2 genotype.

To clarify the relation between the genetic polymorphism of ALDH2 (low Km aldehyde dehydrogenase) and toluene metabolism. The study subjects were 253 toluene workers (192 men and 61 women with an age range of 18-66). The genotypes of ALDH2 were classified by artificial restriction fragment length polymorphism into the homozygous genotype of normal ALDH2 (NN), the homozygous genotype of an inactive ALDH2 (DD), and the heterozygous genotype of normal and inactive ALDH2 (ND). The concentrations of hippuric acid (HA), the main metabolite of toluene, was determined in urine specimens of 253 toluene workers. The HA measurements in previous occupational health examinations were also referenced. The HA concentrations corrected for creatinine (HA/C) were compared with the biological exposure index (BEI) for toluene, which is 2.5 g/g creatinine. To estimate the toluene exposures, urinary o-cresol concentrations were also determined and compared with another BEI for toluene--that is, 1.0 mg urinary o-cresol/g creatinine. Incidence of each genotype in the toluene workers was almost the same as that in non-exposed controls who lived in the same area as the toluene workers. The incidence of each of the three genotypes also did not differ by smoking habit. Mean urinary HA concentrations were not significantly different in the groups with the different genotypes of ALDH2. The HA concentrations of > 70% of the 890 total samples were < 1.0 g/l. The number of urine samples > 3.0 g/l was 28 (5.4%) in the NN group and 19 (6.4%) in the ND group. No urine samples in the DD group were > 3.0 g/l HA. The distribution of urinary HA in the DD group was significantly different from those in both the NN and ND groups (P < 0.05). Seven (4.9%) of the 136 total specimens in the NN group and four (4.7%) of the 82 total specimens in the ND group exceeded the BEI. There were, however, no urine specimens that exceeded the BEI in the DD group. The maximum HA concentration after correction for creatinine in the DD group was 1.86 g/g creatinine. The percentages of urine specimens in which o-cresol concentrations exceeded this BEI were 14.3% in the NN group, 9.1% in the ND group, and 15.4% in the DD group. Therefore, the exposure rate for all three genotypic groups of workers was almost the same. The HA concentrations of toluene workers with ALDH2 DD genotype were lower than those of the NN and ND genotypes when they were exposed to relatively high concentrations of toluene. The exposures of the DD group were suspected to be underestimates because they were based on the BEI for the NN genotype.

Identification of halothane genotypes by calcium accumulation and their meat quality using live pigs

The three halothane genotypes (NN, Nn, and nm) were identified by measuring the capacity for Ca 2+ accumulation by sarcoplasmic reticulum in whole muscle homogenate preparations of M. longissimus dorsi with a Ca 2+ specific electrode at 35°C. Significant differences ( P < 0·001) in deterioration (%) of Ca 2+ accumulation, 12% for NN, 35% for Nn, and 81% for nn pigs, were observed after ageing the whole muscle homogenate preparations for 24 h in ice. Predictions of meat quality in live pigs ( n = 34) based on the values for water-holding capacity, assessed as fluid (g/0·5 g wet wt LD), and pH (fluid) by using small biopsy LD samples (Cheah et al. 1993) were performed on all the halothane genotypes. The halothane genotype NN ( n = 11) showed a fluid value of 0·37 ± 0·01 and a pH (fluid) value of 6·62 ± 0·03 as compared with 0·61 ± 0·02 and 5·84 ± 0·04, respectively, for the halothane genotype nn ( n = 13). The Nn pigs ( n = 10) showed fluid (0·49 ± 0·03) and pH (fluid) (6·19 ± 0·11) values between those values observed for the two homozygotes (NN and nn). Predictions of meat quality in live pigs from biopsy LD muscles were confirmed from assessments on post-mortem LD muscles based on pH 1 and fibre optic probe (FOP) measurements. The extent of deterioration (%) in Ca 2+ accumulation showed high correlations with fluid ( r = −0·861) and pH (fluid) ( r = −0·831) in the biopsy LD samples, and with pH 1 ( r = 0·663), FOP ( r = −0·812), and drip (%) loss ( r = −0·777) in the post-mortem LD samples.

The effect of ante mortem electrolyte therapy on animal physiology and meat quality in pigs segregating at the halothane gene

The present study was initiated to investigate the effect of oral potassium (600 mg, slow release, 24 h preslaughter), intramuscular (IM) magnesium (500 mg MgSO4, 2 h preslaughter) or slow release magnesium (Magnesium-aspartate-hydrochloride (Mg Asp) 20 or 40 (g d−1 for 5 d) on animal physiology and pork quality. Experiments were undertaken on 318 barrows and gilts (100 kg ± 5 kg) represented by three genotypes segregating at the halothane locus (nn, Nn and NN genotypes). Experiment 1 indicated that the oral potassium effectively (P ≤ 0.05) reduced pCO2 values in the nn genotype. Intramuscular injectable magnesium treatments were also found to raise plasma magnesium (P &lt; 0.05) but did not alter muscle, liver or heart tissue levels. Both oral potassium and i.m. magnesium exacerbated subjective pork structure and texture scores but were found to increase muscle brightness and hue (higher b* value). In exp. 2, oral magnesium-aspartate (Mg Asp) was found to raise plasma, but not tissue, levels of magnesium. When fed to a group of halothane carrier pigs (Nn genotype), Mg Asp reduced muscle temperature 45 min post-stunning, increased muscle redness (CIE a* value) and reduced muscle drip loss (P &lt; 0.06). It was concluded that oral potassium and i.m. magnesium as administered in the present study had no beneficial effects on pork quality but that the beneficial effects of Mg Asp on meat colour and drip loss may warrant further investigation. Key words: Magnesium, potassium, preslaughter, pork quality, PSE pork

Halothane gene and swine performance.

One hundred thirty-one pigs representing seven different breed groups (Minnesota No. 1 [M], Pietrain [P], Yorkshire [Y], and crosses PY, P[PY], P[NP], and P[YP]P) and three halothane gene genotypes (NN, Nn, and nn) were tested for breed, sex, and halothane gene (HAL) effects on growth and carcass performance. Breed effects were significant for all traits measured. Sex effect was significant for most traits except for meat scores. The HAL-locus linkage group explained 20 to 30% of the total variation for meat quality scores and 1 to 10% for meat quantity and growth traits. Pietrain x Yorkshire was the fastest growing breed group and had relatively good carcass quality. Pietrain and its related crosses had the most lean muscle but the lowest meat quality. The HN (HAL negative, genotype Nn) individuals within the PPY and PNP groups grew more quickly and had higher meat quality scores and less muscling than HP (HAL positive, genotype nn) individuals. A second experiment with 40 pigs showed significant differences in fat concentration in the loin muscle between breeds (M, Y, and P) and between genotypes within the NP population (NP[HP] and NP[HN]). The phenotypic correlation between fat percentage and marbling was .59 (P less than .01). The NP(HP) had higher water percentage in lean than the NP(HN). The water percentage was negatively correlated with meat quality scores of color, firmness, and marbling with phenotypic correlations of -.10, -.23, and -.57 (P less than .01), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Localization, conjugation, and function of salicylic acid in tobacco during the hypersensitive reaction to tobacco mosaic virus.

Salicylic acid (SA) is hypothesized to be a natural signal that triggers the systemic induction of pathogenesis-related proteins and disease resistance in tobacco. When Xanthi-nc (NN genotype) tobacco was inoculated with tobacco mosaic virus (TMV) there was an increase in endogenous SA in both inoculated and virus-free leaves. The highest levels of SA were detected in and around necrotic lesions that formed in response to TMV. Chemical and enzymatic hydrolysis of extracts from TMV-inoculated leaves demonstrated the presence of a SA conjugate tentatively identified as O-beta-D-glucosyl-SA. The SA conjugate was detected only in leaves that contained necrotic lesions and was not detected in phloem exudates or uninoculated leaves of TMV-inoculated Xanthi-nc tobacco. When exogenous SA was fed to excised tobacco leaves, it was metabolized within 10 hr. However, this reduction in free SA did not prevent the subsequent accumulation of the PR-1 family of pathogenesis-related proteins. The absence of SA accumulation in TMV-inoculated tobacco plants incubated at 32 degrees C was not a result of the glucosylation of SA. The addition of SA to the medium elevated levels of SA in the leaves of virus-free tobacco grown hydroponically. Increasing the endogenous level of SA in leaves to those naturally observed during systemic acquired resistance resulted in increased resistance to TMV, expressed as a reduction in lesion area. These data further support the hypothesis that SA is a likely natural inducer of pathogenesis-related proteins and systemic acquired resistance in TMV-inoculated Xanthi-nc tobacco.

The effect of the halothane gene on pork production and meat quality of pigs reared under commercial conditions

Production and meat quality traits were evaluated on 74 commercially raised heterozygous pigs (Nn) and 50 homozygous normal pigs (NN) at the halothane locus, with an average carcass weight of 79.7 kg. Eight-week weight, average daily gain and age to market, as well as measures of carcass quality (i.e., dressing percent, grade site fat and muscle depths and predicted lean yield) did not differ among pigs with Nn and NN genotypes. The longissimus dorsi muscle from Nn and NN pigs had similar subjective colour and structure scores. Reflectance meter readings (CIE L*-values) were significantly higher on chops from Nn than from NN pigs taken from the centre (57.4 vs. 55.6) and from the anterior portion (56.2 vs. 54.5) of the loin. Drip loss among Nn pigs was higher than among NN pigs for chops taken from the centre (4.8 vs. 3.8 g 100 g−1) and from the anterior portion (3.7 vs. 2.9 g 100 g−1) of the loin (P &lt; 0.01). Soluble protein was 1.7% lower (P &lt; 0.001) in Nn pigs compared with the NN pigs. Barrows attained market weight earlier (P &lt; 0.05) than gilts, but they had a lower dressing percentage (P &lt; 0.05) and greater grade fat depth (P &lt; 0.001) and had 1.2% less predicted lean yield of carcass (P &lt; 0.001) than gilts. Since meat quality declined without concomitant increases in growth rate or improvements in carcass quality, it was concluded that the intentional use of the halothane gene should be discouraged. Key words: Swine, production, carcass quality, meat quality, halothane gene

Growth characteristics and carcass composition of pigs with known genotypes for stress susceptibility over a weight range of 70 to 120 Kg

ABSTRACTA total of 805 Lacombe pigs of different genotype with respect to halothane sensitivity (halothane positive, nn = 205; heterozygote, Nn = 214; halothane negative, NN = 386) were slaughtered over a range in live weight (70 to 120 kg) to assess tissue growth patterns using the allometric equation (y = aXh). The nn genotype was older at slaughter than the NN genotype, but pigs from each genotype were killed over a similar weight range. The relative growth of the primal cuts was influenced by genotype, with nn pigs having a lower coefficient for the bottom shoulder (picnic) and a higher coefficient for the belly. The relative growth of bone was similar for genotypes (P &gt; 0·05) but the relative growth of lean was lower and the relative growth of total fat and depot fat (subcutaneous and intermuscular) was higher for the nn genotype compared with the Nn and NN genotypes. On a within-tissue basis, the relative growth of the tissues in each primal was similar, except for the ham, where the relative growth of lean was higher for nn pigs compared with the two other genotypes. Small differences in tissue distribution were evident, but seldom exceeded 30 g/kg. Although nn pigs had a higher lean content and higher lean: bone ratio than Nn or NN pigs at similar live weights, their relative advantage in composition decreased with increasing live weight.

Altered function of the tobacco mosaic virus movement protein in a hypersensitive host

The N gene in Nicotiana sp. confers hypersensitive resistance to all strains of tobacco mosaic virus (TMV) and limits the rate of virus spread in infected leaves. To examine the role of the movement protein (MP) of TMV in the hypersensitive reaction (HR), transgenic Nicotiana tabacum cv. Xanthi-nc (genotype NN) plants that express the MP gene were produced and the molecular size exclusion limit of plasmodesmata in leaf mesophyll cells was monitored. At the HR-permissive temperature (24°) movement from cell to cell of fluorescein isothiocyanate-labeled dextran of molecular mass 3.9 kDa was detected while 9.4-kDa molecules failed to move. At the HR-non permissive temperature (33°) the 9.4-kDa probe moved readily from cell to cell. In contrast, in transgenic Xanthi (genotype nn) which express the MP gene the 9.4-kDa probe moved from cell to cell at 24 and 33°. These results suggest that the N gene may modify the ability of the MP to alter plasmodesmata molecular exclusion limits, although expression of the TMV-MP gene alone did not induce the HR. Furthermore, when MP(+) Xanthi-nc tobacco lines were inoculated with a TMV that lacked a MP gene the HR was induced, and the concentration of MP in the transgenic lines was correlated with the degree of the HR.

Stunning and shackling influences on quality of porcine Longissimus dorsi and Semimembranosus muscles

Seventy-one barrows of three porcine genotypes (nn, Nn and NN genotypes with respect to halothane) were electrically stunned on the right side and randomly assigned to one of three treatments during the bleeding process (prone, PR; shackled left, SL; or shackled right, SR) to investigate the influence of both shackling and stunning on ultimate meat quality. PR carcasses had less side-to-side variation in 40 min pH than either SL or SR carcasses. Shackling contributed to a decreased 40 min pH in the semimembranosus (SM) and posterior longissimus dorsi (PL). The effects of stunning appeared to be additive when combined with shackling, tending to lower pH in the mid- longissimus dorsi (ML; P <- 0·10). The ‘free’ side of the shackled carcass also had significantly lower 40 min pH in the ML, PL and SM locations when compared to PR sides. Genotype had no influence on shackling since there was no treatment by genotype interactions. Despite significant effects on post-mortem metabolism (indicated by the differences in 40 min pH) shackling alone had little influence on overall ultimate meat quality of the carcass. Depending on the sampling location, soluble protein and L ∗ and b ∗ values varied among treatments. Shear force and a ∗ values were similar among treatments, but PR and SL carcasses had significantly lower expressible juice and drip loss compared to SR carcasses. These results suggest that, although shackling alone has little effect on meat quality, in combination with electrical stunning, shackling can lead to a decrease in meat quality.

INFRARED THERMOGRAPHY OF PIGS WITH KNOWN GENOTYPES FOR STRESS SUSCEPTIBILITY IN RELATION TO PORK QUALITY

Twenty five market-weight pigs averaging 92.0 kg body weight represented by eight halothane-negative with NN genotype, nine crossbred with Nn genotype and eight halothane-positive with nn genotype animals were thermographed to determine whether temperature differences were related to meat quality. Infrared thermograph analysis demonstrated no differences in mean external medial temperatures among genotypes in the live animal nor in the internal medial carcass surface. However, pigs with cooler mean side temperatures displayed a higher percent drip loss (P ≤ 0.09) and paler colored meat (P ≤ 0.03). This was particularly evident in the H+ pigs where a highly significant negative correlation between expressible juice (−0.87; P ≤ 0.01) as well as percent drip loss (−0.75; P ≤ 0.05) and mean live external medial surface temperature was observed. Furthermore, the halothane-positive pigs displayed small hot spots over the dorsal front shoulder area and over the posterior third of the animals. Key words: Infrared thermography, meat quality, pig genotype

Behaviour in pigs from three genotypes segregating at the halothane locus

The intention of the present study was to identify unique behaviour traits in halothane-positive pigs, as well as crossbred carriers of the halothane gene, compared to halothane-negative pigs. The identification of such traits may be useful in forming guidelines for management and environment changes aimed at improving pork quality. Twenty-four-hour VHS time-lapse recordings were collected on 16 halothane-negative pigs (H −; NN genotype), 16 halothane-positive pigs (H +; nn genotype) and 16 pigs which were the F 1 progeny of H +×H − (H +−; Nn genotype). Ethograms constructed from these tapes revealed that H + pigs drank and ate less frequently than H − or H +− pigs and were also more active with respect to pen investigative behaviour ( P≤0.01). Halothane-positive pigs also slept more frequently in groups and displayed fewer total aggressive acts than the other two genotypes ( P≤0.01). Both H + and H +− pigs displayed comparatively greater levels of neutral/non-aggressive acts, including nose-nose and nose-body contact ( P≤0.01). However, when subjected to either 24 or 48 h off feed, all genotypes behaved in a similar manner, generally reducing the level of activity in most behaviour traits. The results of the present study suggest that genotype differences in behaviour among these three genotypes do exist.

THE EFFECT OF PRESLAUGHTER FEED RESTRICTION AND GENOTYPE FOR STRESS SUSCEPTIBILITY ON PORK LEAN QUALITY AND COMPOSITION

The effect of the duration of feed restriction prior to slaughter on the ultimate lean meat quality of the longissimus dorsi muscle (loin-eye) was tested in three lines of pigs of differing genotypes with respect to stress susceptibility. Pigs of the Lacombe breed (genotype NN), none of which has been shown to be halothane-positive, yielded a low incidence (0–4%) of pale or soft, exudative pork for all three feed restriction treatments (0,24 and 48 h off feed). The meat quality of pigs from the halothane-positive line (genotype nn) was altered dramatically by the off-feed treatment. The incidence of pale-colored pork decreased from 57% at 0 h off feed to 9% at 48 h off feed, and the incidence of soft, exudative pork decreased from 87% at 0 h off feed to 48% at 48 h off feed. NN × nn crossbred pigs (genotype Nn), all of which gave a negative response to the halothane test, were intermediate in quality between the other two genotypes at all times off feed. In no instance did the feed restriction treatment produce dark, firm, dry (DFD) meat. These data suggest, first, that halothane-negative carriers of the halothane gene may contribute considerably to the incidence of pale, soft, exudative (PSE) pork, and secondly, the manipulation of the length of time of feed prior to shipping for slaughter may offer potential as a management practice to improve meat quality. Key words: Feed restriction, fasting, stress susceptible, quality

BODY PROPORTIONS AND CARCASS COMPOSITION OF PIGS WITH KNOWN GENOTYPES FOR STRESS SUSCEPTIBILITY FASTED FOR DIFFERENT PERIODS OF TIME PRIOR TO SLAUGHTER

A total of 233 pigs from a halothane positive line (genotype nn), from a halothane-negative line (genotype NN) and their cross (genotype Nn) were allocated to three treatments when their liveweight approximated 95 kg. Treatment 1 consisted of immediate slaughter following removal of the pigs from their pens, treatment 2 involved a period of 24 h of feed restriction prior to slaughter and treatment 3 a period of 48 h of feed restriction prior to slaughter. All carcasses were weighed on the slaughter floor and cooled at 1 °C for 24 h prior to dissection of the side into fat, lean and bone. Relative to liveweight, nn pigs had a higher proportion of carcass (41 g kg−1, P &lt; 0.001) and a lower proportion of body organs (8 g kg−1, P &lt; 0.001), body fat depots (7 g kg−1, P &lt; 0.001), alimentary tract (14 g kg−1, P &lt; 0.001) and gutfill (12 g kg−1, P &lt; 0.001) than NN pigs. Nn pigs had values that were generally intermediate to nn and NN pigs. The proportion of carcass (22 g kg−1), body organs (5 g kg−1), alimentary tract (6 g kg−1) and gutfill (21 g kg−1) were reduced (P &lt; 0.05) as fasting increased from 0 to 48 h relative to market weight. Linear fat thickness measurements made on the midline of the warm carcass were similar for nn and NN pigs except for the maximum loin (32.2 vs 28.6 mm for nn vs. NN). However, nn pigs had a lower proportion (P &lt; 0.05) of fat (35 g kg−1), bone (13 g kg−1) and skin (11 g kg−1), and a higher proportion of lean (60 g kg−1) in their carcasses than those from NN pigs. Carcasses from Nn pigs had less skin (4 g kg−1) and bone (7 g kg−1), but more lean (11 g kg−1) and similar fat content to those from NN pigs. It was concluded that fasting for up to 48 h prior to slaughter had a similar effect on the three genotypes, but there were large differences among genotypes in body components and carcass composition. Key words: Stress susceptibility, fasting, carcass, organs, gutfill, composition, pigs

In vitro translation products of mrnas derived from TMV-infected tobacco exhibiting a hypersensitive response

Expression of the hypersensitive response (HSR) to tobacco mosaic virus (TMV) infection in Nicotiana tabacum L. cv. Xanthi-nc (genotype NN) is controlled by the single dominant “N” gene and is temperature sensitive. TMV-infected Xanthi-nc tobacco plants grown at the HSR-restrictive temperature of 31° for 3 days postinoculation show necrosis approximately 8 hr after the temperature shift to the HSR-permissive temperature of 25°. Both polyribosomal and total cytoplasmic poly(A)-containing RNAs were isolated at various times after the temperature shift from leaves of TMV-infected and mock-infected Xanthi-nc tobacco plants and from TMV-infected Turkish Samsun tobacco plants (genotype nn; systemic for TMV infection). The RNAs were translated in vitro and the products were analyzed by polyacrylamide gel electrophoresis. A minimum of four polypeptide translation products specific to both the polyribosomal and total cytoplasmic poly(A)-containing RNAs derived from hypersensitively responding Xanthi-nc were observed.

Rhesus and MN Blood Types

To the Editor: —Statistically significant evidence of associations between duodenal and gastric ulcer, gastric carcinoma, rheumatic fever, and the Rhesus and MN blood groups has been reported ( JAMA 179 :479-485 [Feb 17] 1962). The frequency of the R1R2 presumptive genotype was found to be significantly increased in patients with gastric carcinoma and duodenal and gastric ulcer, and the R2r, (r'r)r and NN genotypes in patients with rheumatic fever; the frequency of the R1R1 and R2r presumptive genotypes was significantly reduced in patients with gastric carcinoma. Clarke et al ( Brit Med J 1 :1734-1736 [June 23] 1962) suggested that these findings might indicate a transfusion effect rather than a cause-and-effect association between the diseases and blood groups. Our data on patients with duodenal and gastric ulcer have been reevaluated by dividing the patients into (A) those who had received blood transfusions 90 days or less prior to the typing done for

The Rhesus and MN Blood Groups and Disease

The possibility of an association of certain disorders with the Rhesus and MN blood groups was investigated in 1,030 duodenal ulcer, 348 gastric ulcer, 170 gastric carcinoma, 540 rheumatic fever, and 1,153 diabetes mellitus patients. This was done by comparing the blood-group frequencies observed in these patients with those observed in 2,186 controls; the differences were examined for statistical significance by appropriate statistical methods. It was found that the liability to duodenal and gastric ulceration was statistically increased in persons of the presumptive Rhesus genotype R 1 R 2 . There was evidence, of less statistical significance, of an association of the Rhesus blood groups with gastric carcinoma and rheumatic fever. A statistically significant increased liability of persons of NN genotype to rheumatic fever was found.