Development and characterization of genetic mapping resources for the turkey (Meleagris gallopavo)

The development and partial characterization of turkey genomic libraries enriched for TG, GAT, and CCT simple sequence repeats (SSR) are described. The primary library, established using conventional methods, was enriched for each of the three SSR by single-primer polymerase chain reaction (PCR). The three enriched libraries were screened by standard hybridization and washing protocols under moderate to high stringency conditions. The utility of a fraction of the markers was evaluated based on the polymorphism of PCR-amplified products in a backcross reference DNA panel. The panel consisted of genomic DNA samples from three backcrossed families developed from a cross of a wild male turkey to three inbred Orlopp line C females. A total of 181 sequences from positive clones have been characterized and deposited in GenBank. About 60% of the 60 primer pairs designed from SSR-containing sequences detected polymorphism in the reference DNA panel. The turkey genomic DNA reference panel, the enriched libraries, and the markers described here provide an opportunity to begin to characterize the turkey genome and to develop a useful public genetic map for this economically important species.     

Relationship of NK3 receptor-immunoreactivity to subpopulations of neurons in rat spinal cord

Exposure to the thiolamine radioprotector N-(2-mercaptoethyl)-1,3-propanediamine (WR-1065) induced apoptosis in the mouse TB8.3 hybridoma after a 60-min (LD50 = 4.5 mM) or during a 20-h (LD50 = 0.15 mM) exposure. In contrast, a 20-h exposure to 17 mM L-cysteine or 10 mM cysteamine was required to induce 50% apoptosis within 20 h. Apoptosis was not induced by either a 60-min or 20-h exposure to 10 mM of the thiazolidine prodrugs ribose-cysteine (RibCys) or ribose-cysteamine (RibCyst). Thiolamine-induced apoptosis appeared to be a p53-independent process since it was induced by WR-1065 exposure in human HL60 cells. Exposure to WR-1065 (4 mM for 15 min) or cysteine (10 mM for 60 min) before and during irradiation protected cells against the induction of both DNA double-strand breaks and apoptosis, while exposure to RibCys (10 mM for 3 h) did not. Treatment with either WR-1065, cysteine, RibCys or RibCyst for 60 min beginning 60 min after irradiation did not affect the level of radiation-induced apoptosis. In contrast, treatment with either cysteine, cysteamine or RibCys for 20 h beginning 60 min after irradiation enhanced radiation-induced apoptosis. Similar experiments could not be conducted with WR-1065 because of its extreme toxicity. Our results indicate that thiolamine enhancement of radiation-induced apoptosis is not involved in their previously reported capacity to reduce radiation-induced mutations.     

delta -function bosons in a one-dimensional potential well

The neuroprotective efficacy of the hydroperoxide scavenger ebselen was assessed in a model of transient focal ischaemia that utilises the potent vasoconstrictor peptide endothelin-1 to induce temporary occlusion of the middle cerebral artery (MCA). Pretreatment with ebselen (10 or 30 mg/kg p.o., 40 min pre-MCA occlusion) dose dependently reduced the volume of ischaemic damage assessed 4 h post-endothelin-1 application in the anesthetised rat. The lower dose of ebselen (10 mg/kg) resulted in a non-significant 35% reduction in the total volume of ischaemic damage compared with the vehicle control. In contrast the higher dose of ebselen (30 mg/kg) significantly reduced the volume of ischaemic damage in the cerebral hemisphere and cerebral cortex by 48% and 53%, respectively. The marked reduction in brain damage achieved with ebselen cannot be attributed to drug-induced alterations in blood pressure, body temperature or arterial blood gases since these physiological variables were closely monitored and were not significantly altered by ebselen treatment. Thus ebselen is an effective neuroprotective agent against acute focal ischaemic-reperfusion injury.     

From good substrates to good inhibitors: design of inhibitors for serine and thiol proteases

Serine and thiol proteases react with peptide substrates to form an acyl-enzyme. We have synthesized inhibitors which are pseudo-substrates and react with the proteases to generate acyl-enzymes which hydrolize slowly. This is achieved by incorporating an electron-donating group near the carbonyl group of inhibitors I [Ac-Phe--C(O)NH--NH--C(O)X] and II [benzyl-O-C(O)-psiAla-Leu-ArgOMe]. The acyl-enzymes derived from the reaction of I with papain and II with chymotrypsin hydrolyze with t1/2 of 12 and 1 h, respectively. The increased electron density on the carbonyl group of the inhibitor also reduces the rate of acyl-enzyme formation. Components were incorporated into the inhibitor which interact with the leaving group binding site (S' subsite) and which accelerate the rate of reaction of inhibitor with enzyme. For inhibitor I, X = NH(CH3), k(on) < 0.13 M(-1) s(-1) for the reaction papain, but if X = psiLeu(CH3)2,k(on) =10(5) M(-1) s(-1). Similar results were obtained with II and chymotrypsin. Concomitant with acyl-enzyme formation, X is released and a slowly hydrolyzing acyl-enzyme remains.     

Testosterone increases and estradiol decreases middle cerebral artery occlusion lesion size in male rats

This study was undertaken to determine the effects of estrogen and testosterone on cerebral ischemic lesion size induced by middle cerebral artery (MCA) occlusion in male rats. Rats were gonadectomized and treated with testosterone, estrogen, or testosterone plus estrogen filled Silastic pellets. The animals were divided into 6 groups: intact, intact + estrogen (E2), castrate, castrate + testosterone (T), castrate + E2, and castrate + T + E2. One week after treatment, cerebral ischemia was induced by MCA occlusion for 40 min, followed by reperfusion. After 24 h, rats were sacrificed and slices were then stained to assess lesion size. The presence of testosterone increased and the removal of testosterone decreased lesion size. A strong positive correlation (r2 = 0.922) between plasma testosterone concentrations and ischemic lesion size was observed. Estradiol treatment reduced ischemic area. In summary, the present study provides evidence that testosterone exacerbates and estrogens ameliorate ischemic brain damage in an animal model of cerebral ischemia.     

The arabidopsis ACT7 actin gene is expressed in rapidly developing tissues and responds to several external stimuli

ACT7 encodes one of the six distinct and ancient subclasses of actin protein in the complex Arabidopsis actin gene family. We determined the sequence and structure of the Arabidopsis thaliana ACT7 actin gene and investigated its tissue-specific expression and regulation. The ACT7 mRNA levels varied by 128-fold among several different tissues and organs. The highest levels of aCT7 mRNA were found in rapidly expanding vegetative organs, the lowest in pollen. A translational fusion with the 5' end of ACT 7 (1.9 kb) joined to the beta-glucuronidase reporter gene was strongly and preferentially expressed in all young, developing vegetative tissues of transgenic Arabidopsis plants. ACT7 was the only Arabidopsis actin gene strongly expressed in the hypocotyl and seed coat. Although no beta-glucuronidase expression was seen in developing ovules or immature seeds, strong expression was seen in dry seeds and immediately after imbibition in the entire seedling. ACT7 was the only Arabidopsis actin gene to respond strongly to auxin, other hormone treatments, light regime, and wounding, and may be the primary actin gene responding to external stimuli. The ACT7 promoter sequence contains a remarkable number of motifs with sequence similarity to putative phytohormone response elements.     

Endothelium-dependent effect of perindopril and enalaprilat in rat thoracic aorta

AIM: To study the effect of the angiotensin-converting enzyme (ACE) inhibitors perindopril (Per) and enalaprilat (Ena) on the reactivity of the endothelium in normal rats. METHODS: Male rats were treated intragastrically with Per (2 mg.kg-1.d-1) or placebo (n = 18) for 6 wk. Aorta was isolated for experiment. Another set of isolated aortic rings with and without endothelium were incubated with Ena (0.1 mumol.L-1) for 30 min. Responses to acetylcholine, serotonin, phenylephrine, sodium nitroprusside (SN), and nitroglycerin (Nit) were observed. RESULTS: Endothelium-dependent relaxation to acetylcholine was augmented in aortic rings from rats treated with Per in comparison with control. The IC50 value (95% confidence limits) decreased from 3.8 (0.56-26.1) mumol.L-1 (control group) to 0.98 (0.28-3.41) mumol.L-1 (Per-treated group). The maximal relaxation was augmented from 62 +/- 9% to 78 +/- 10% (P < 0.01). However, the responses to the endothelium-independent vasodilators, SN and Nit, were similar. Serotonin- and phenylephrine-induced contractions were decreased, which were influenced by basal release of endothelium-derived relaxing factor (EDRF). EC50 values was 6.1 (2.6-14.4) nmol.L-1 vs 8.3 (3.6-18.8) nmol.L-1 in comparison with control group and Per-treated group. The maximal contraction was decreased from 2.42 +/- 0.29 g (control group) to 1.96 +/- 0.25 g (treated group) (P < 0.01). Similar results were found in incubation with Ena. CONCLUSION: Ena and Per enhanced the basic release of EDRF from vascular endothelium.     

Randomized study of chemoembolization as an adjuvant therapy for primary liver carcinoma after hepatectomy

From April 1990 to December 1993, 140 patients were recruited to a randomized study to evaluate transcatheter hepatic arterial chemoembolization (TACE) as an adjuvant therapy for primary liver carcinoma after hepatectomy. This study investigated the principle, techniques and results of TACE. The results showed that the intrahepatic recurrence rate was 48.9% in the patients who underwent radical resection only, but only 21.3% in the patients who also underwent TACE 3-4 weeks after hepatectomy (P < 0.01). The 1-, 2-, 3-, and 4-year survival rates were 72.3%, 52.7%, 35.1%, and 35.1% respectively for the patients who underwent radical resection only, and were 97.9%, 85.5%, 69.5%, and 56.9% for the patients who also underwent TACE 3-4 weeks after radical resection (P < 0.001). The 1-, 2-, 3-, and 4-year survival rates were 38.9%, 0%, 0%, and 0% for the patients who underwent palliative resection only, and were 68.3%, 32.3%, 21.5%, and 21.5% respectively for the patients undergoing TACE 3-4 weeks after palliative hepatectomy (P < 0.001).