Morphine-potentiated platelet aggregation in in vitro and platelet plug formation in in vivo experiments

The detailed mechanisms underlying morphine-signaling pathways in platelets remain obscure. Therefore, we systematically examined the influence of morphine on washed human platelets. In this study, washed human platelet suspensions were used for in vitro studies. Furthermore, platelet thrombus formation induced by irradiation of mesenteric venules with filtered light in mice pretreated with fluorescein sodium was used for an in vivo thrombotic study. Morphine concentration dependently (0.6, 1, and 5 microM) potentiated platelet aggregation and the ATP release reaction stimulated by agonists (i.e., collagen and U46619) in washed human platelets. Yohimbine (0.1 microM), a specific alpha(2)-adrenoceptor antagonist, markedly abolished the potentiation of morphine in platelet aggregation stimulated by agonists. Morphine also potentiated phosphoinositide breakdown and intracellular Ca(2+) mobilization in human platelets stimulated by collagen (1 microg/ml). Moreover, morphine (0.6-5 microM) markedly inhibited prostaglandin E(1) (10 microM)-induced cyclic AMP formation in human platelets, while yohimbine (0.1 microM) significantly reversed the inhibition of cyclic AMP by morphine (0.6 and 1 microM) in this study. The thrombin-evoked increase in pH(i) was markedly potentiated in the presence of morphine (1 and 5 microM). Morphine (2 and 5 mg/g) significantly shortened the time require to induce platelet plug formation in mesenteric venules. We concluded that morphine may exert its potentiation in platelet aggregation by binding to alpha(2)-adrenoceptors in human platelets, with a resulting inhibition of adenylate cyclase, thereby reducing intracellular cyclic AMP formation followed by increased activation of phospholipase C and the Na(+)/H(+) exchanger. This leads to increased intracellular Ca(2+) mobilization, and finally potentiation of platelet aggregation and of the ATP release reaction.     

Stereoselective metabolism of pentoxifylline in vitro and in vivo in humans

Pentoxifylline increases erythrocyte flexibility, reduces blood viscosity, and inhibits platelet aggregation and is thus used in the treatment of peripheral vascular disease. It is transformed into at least seven phase I metabolites, of which two, M1 and M5, are active. The reduction of the keto group of pentoxifylline to a secondary alcohol in M1 takes place chiefly in erythrocytes, is rapidly reversible, and creates a chiral center. The aims of this study were: to develop HPLC methods to separate the enantiomers of M1, to investigate the kinetics of the reversible biotransformation of pentoxifylline to (R)- and (S)-M1 in hemolysed erythrocyte suspension, and to quantify the formation of the enantiomers of M1 (as well as M4 and M5) after intravenous and oral administration of pentoxifylline to human volunteers. (R)- and (S)-M1 could be separated preparatively on a cellobiohydrolase column, while determination in blood or plasma was by HPLC after chiral derivatization with diacetyl-L-tartaric acid anhydride. The metabolism of pentoxifylline to (R)-M1 in suspensions of hemolysed erythrocytes followed simple Michaelis-Menten kinetics (K(m) = 11 mM), while that to (S)-M1 was best described by a two-enzyme model (K(m) = 1.1 and 132 mM). Studies with inhibitors indicated that the enzymes were of the carbonyl reductase type. At a therapeutic blood concentration of pentoxifylline, the calculated rate of formation of (S)-M1 is 15 times higher than that of the (R)-enantiomer. Back-conversion of M1 to pentoxifylline was 3-4 times faster for the (S)- than for the (R)-enantiomer. In vivo, the R:S plasma concentration ratio of M1 ranged from 0.010-0.025 after intravenous infusion of 300 or 600 mg of pentoxifylline, and from 0.019-0.037 after oral administration of 600 mg. The biotransformation of pentoxifylline to M1 was thus highly stereoselective in favor of the (S)-enantiomer both in vitro and in vivo.     

Mutations in oxyR resulting in peroxide resistance in Xanthomonas campestris

A spontaneous Xanthomonas campestris pv. phaseoli H(2)O(2)-resistant mutant emerged upon selection with 1 mM H(2)O(2). In this report, we show that growth of this mutant under noninducing conditions gave high levels of catalase, alkyl hydroperoxide reductase (AhpC and AhpF), and OxyR. The H(2)O(2) resistance phenotype was abolished in oxyR-minus derivatives of the mutant, suggesting that elevated levels and mutations in oxyR were responsible for the phenotype. Nucleotide sequence analysis of the oxyR mutant showed three nucleotide changes. These changes resulted in one silent mutation and two amino acid changes, one at a highly conserved location (G197 to D197) and the other at a nonconserved location (L301 to R301) in OxyR. Furthermore, these mutations in oxyR affected expression of genes in the oxyR regulon. Expression of an oxyR-regulated gene, ahpC, was used to monitor the redox state of OxyR. In the parental strain, a high level of wild-type OxyR repressed ahpC expression. By contrast, expression of oxyR5 from the X. campestris pv. phaseoli H(2)O(2)-resistant mutant and its derivative oxyR5G197D with a single-amino-acid change on expression vectors activated ahpC expression in the absence of inducer. The other single-amino-acid mutant derivative of oxyR5L301R had effects on ahpC expression similar to those of the wild-type oxyR. However, when the two single mutations were combined, as in oxyR5, these mutations had an additive effect on activation of ahpC expression.     

Multiple biomarkers study in painters in a shipyard in Korea

Shipbuilding workers are exposed to a variety of genotoxic compounds including polycyclic aromatic hydrocarbons (PAHs). A limited number of studies have been conducted to evaluate biomarkers related to PAH exposure in painters in the shipyard industry. We examined this in 208 workers recruited from a shipyard located in South Korea. Employees were grouped into three exposure groups: (1) 111 painters using coal tar paints, (2) 70 painters using general paints, and (3) 27 on-site controls using no paints. Levels of urinary 1-hydroxypyrene glucuronide (1-OHPG), as internal dose of PAH exposure, were measured by synchronous fluorescence spectroscopy. Glutathione S-transferase (GST) M1 and T1 genotypes were assessed by a multiplex polymerase chain reaction (PCR)-based method, aromatic-DNA adducts in peripheral white blood cells were measured by 32P-postlabeling, and glycophorin A (GPA) variant frequencies in red blood cells were assessed by flow cytometry. Information on demographic characteristics, smoking habits, diet, job title and use of personal protective equipment (e.g. respiratory and dermal) were collected by self-administered questionnaire. Average urinary 1-OHPG levels in coal tar paint (2.24 micromol/mol creatinine) and general paint (1.38 micromol/mol creatinine) users were significantly higher than in on-site controls (0.62 micromol/mol creatinine) (P<0.001). Paint use, irrespective of the type of paints, and smoking (yes/no) were positively associated with urinary 1-OHPG levels, whereas green tea consumption (yes/no) was negatively associated with the 1-OHPG levels. No significant effect in the 1-OHPG levels were observed for the GSTM1 and GSTT1 genotypes. Aromatic-DNA adduct levels tended to be higher in coal tar paint users (P = 0.06) and painters (P = 0.07) compared to on-site controls. No differences in adduct levels were observed, between the two groups of painters, and the combined group showed greater adduct levels than on-site controls (P = 0.05). GPA mutation frequencies measured in 55 individuals with MN heterozygote genotypes were not significantly different among the three exposure groups, and no correlation was observed between urinary 1-OHPG levels and aromatic-DNA adducts or GPA mutation frequency. These results suggest that painters in the shipyard were exposed to significant amounts of PAHs and possibly to other genotoxic aromatic compounds, and that urinary 1-OHPG may be a potential biomarker of PAH exposure in this population.     

Parasympathetic involvement in PAF-induced contraction in canine trachealis in vivo

We studied the contractile response elicited by platelet-activating factor (PAF) administered intra-arterially into the tracheal circulation of 34 dogs in vivo. A method that avoided tachyphylaxis encountered in prior investigations was developed for isometric measurement of multiple dose-response effects. PAF was a very potent contractile agent; active tension was elicited with 10(-11) mol ia PAF. To determine the mechanism by which contraction was induced, dose-response curves were generated in groups of five animals each treated with either 0.5 mg/kg (approximately 1.5 X 10(-5) mol) iv + 10(-3) mg/kg (3 X 10(-8) mol) ia atropine, 5 mg/kg iv indomethacin (INDO), or 7.5 mg/kg iv hexamethonium (HEX). After pretreatment with atropine, contraction still was elicited with 10(-11) mol ia PAF. However, maximal contraction was only 16.2 +/- 2.74 g/cm (vs. 35.7 +/- 5.74 g/cm for untreated controls; P less than 0.02). The dose at which maximal contraction was elicited after atropine was 10(-7) mol ia (vs. 1.9 X 10(-9) mol for controls; P less than 0.001). Pretreatment with INDO caused minimal attenuation, and HEX had no effect on the response elicited by ia PAF. We demonstrate a method for assessing the effects of PAF in central airways that avoids tachyphylaxis and permits dose-response studies in the same animal. We also demonstrate that PAF is an extremely potent mediator that elicits tracheal smooth muscle contraction at least in part by postganglionic activation of parasympathetic nerves. A direct contractile effect of PAF which is not related to secretion of products of the cyclooxygenase pathway is also suggested.     

Gender-related differences in maximum mechanical power output in short-term activities in children and adolescents

The study was designed to examine the gender-related differences in maximum mechanical power output in various short-burst activities during growth. The subject sample consisted of four subgroups: 9 boys (14.11 +/- 0.6 yr), 9 boys (10.67 +/- 0.71 yr), 7 girls (14.29 +/- 0.49 yr), 7 girls (10.57 +/- 0.54 yr). We measured peak power (PP), mean power (MP), fatigue index (FI) during 30-s WAnT, squat jump height (SJH) and power (SJP), and counter movement jump height (CMJH) and power (CMJP), maximum speed over 20-metre distance (S20). Lactation concentration was measured in the 3rd and 5th minutes after the WAnT Ratio normalisation and ANCOVA were used to remove the influence of the differences in muscle (MM) and body mass (BM). Male adolescents had higher absolute values of PP (P < 0.05), MP (P < 0.05) than female. Ratio normalisation showed that boys had higher PP/BM (P < 0.05), PP/MM (P < 0.05), MP/BM (P < 0.05), MP/MM (P < 0.06) than girls. The ANCOVA adjustment for MM showed differences between genders in PP (P < 0.001), MP (P < 0.001), SJH (P < 0.05), SJP (P < 0.05) and CMJP (P < 0.001), whereas the ANCOVA adjustment for BM showed differences only in PP (P < 0.001), MP (P < 0.001). Prepubertal boys had higher absolute values only in SJP (P < 0.05). We concluded that variations in body composition could not be the only key to gender-related differences in power output in short-burst activities.     

Importance of guanine nitration and hydroxylation in DNA in vitro and in vivo

Guanine (Gua) modification by nitrating and hydroxylating systems was investigated in DNA. In isolated calf thymus DNA, 8-NO(2)-Gua and 8-oxo-Gua were dose-dependently formed with peroxynitrite, and 8-NO(2)-Gua was released in substantial amounts. Myeloperoxidase (MPO) with H(2)O(2) and NO(2)(-) reacted with calf thymus DNA to form 8-NO(2)-Gua dose dependently without release of 8-NO(2)-Gua. The frequency of strand breaks was higher than the sum of 8-NO(2)-Gua and 8-oxo-Gua, particularly in the MPO-treated DNA, indicating the importance of other types of damage. The activation of human neutrophils and lymphocytes with phorbol ester did not induce 8-NO(2)-Gua and 8-oxo-Gua in their nuclear DNA. However, 8-NO(2)-Gua was found in calf thymus DNA co-incubated with activated neutrophils in the presence of NO(2)(-). No significant formation of 8-NO(2)-Gua was found in liver DNA from mice treated with Escherichia coli lipopolysaccharide. The incubation of peroxynitrite or MPO-H(2)O(2)-NO(2)(-)-treated DNA with formamidopyrimidine glycosylase (Fpg) released 8-oxo-Gua, but not 8-NO(2)-Gua, indicating that 8-NO(2)-Gua is not a substrate for Fpg. Although 8-NO(2)-Gua was generated in isolated DNA by different nitrating systems, other types of damage were formed in abundance, and the lesion could not be found reliably in nuclear DNA, suggesting that the biological importance is limited.     

S-Transnitrosylation of albumin in human plasma and blood in vitro and in vivo in the rat

S-Nitrosoalbumin (SNOALB) is the most abundant physiological circulating nitric oxide (NO) carrier regulating NO-dependent biological actions in humans. The mechanisms of its formation and biological actions are still incompletely understood. Nitrosation by authentic NO and S-transnitrosylation of the single sulfhydryl group located at Cys-34 of human albumin by the physiological S-nitroso compounds S-nitrosocysteine (SNOC) and S-nitrosoglutathione (GSNO) are two possible mechanisms. On a quantitative basis, we investigated by gas chromatography-mass spectrometry the contribution of these two mechanisms to SNOALB formation in human plasma and blood in vitro. GSNO and SNOC (0-100 microM) rapidly and efficiently (recovery=35%) S-transnitrosylated albumin to form SNOALB. NO (100 microM) S-nitrosated albumin to SNOALB at a considerably lower extent (recovery=5%). The putative NO-donating drugs glyceryl trinitrate and sodium nitroprusside (each 100 microM) failed completely in S-nitrosating albumin. Bubbling NO into human plasma and blood resulted in formation of SNOALB that inhibited ADP-induced platelet aggregation. Infusion of GS(15)NO in the rat resulted in formation of S(15)NOALB, [(15)N]nitrate and [(15)N]nitrite. Our results suggest that S-transnitrosylation of albumin by SNOC and GSNO could be a more favored mechanism for the formation of SNOALB in the circulation in vivo than S-nitrosation of albumin by NO itself.     

Oxygen tension in cerebral microvessels in acute anaemia in rats

Using polarographic oxygen microelectrodes, distribution of oxygen tension (pO2) in the rat cerebral arterioles (with a lumen diameter of 8-80 microm) and venules (with a lumen diameter of 8-120 microm) has been studied in acute reduction of haemoglobin concentration in the blood. Isovolumic haemodilution with 5 % albumin solution has been performed stepwise from 14 g/dl (control) to 10 g/dl (step 1), 7 g/dl (step 2) and to 4.6 g/dl (step 3). It was shown that step 1 of haemodilution led to no impairment of oxygen supply to the brain cortex. Step 2 resulted in moderate increase of pO2 in arterioles, whereas in venules oxygen tension fell down substantially (on the average, to 32 mm Hg). Step 3 resulted insignificant increase of pO2 in arterioles. A further fall of pO2 (to 27 mm Hg) in studied venules was recorded. The portion of venules with low pO2 grew to 31% (only 3 % in control). Microregions with a near-to-zero pO2 were recorded in some capillaries. This indicates presence of hypoxic zones in brain tissue. Hypoxic and anoxic microregions originate at this stage of anemia in locations with relatively low and/or impaired blood supply.     

Iron-induced oxidative DNA damage in rat sperm cells in vivo and in vitro

We investigated whether acute iron intoxication causes oxidative DNA damage, measured in terms of 7-hydro-8-oxo-2'-deoxyguanosine, 8-oxodG, in nuclear DNA in testes and epididymal sperm cells in vivo and in vitro in rats. In addition, we investigated levels of the modified nucleoside in liver and kidney and measured its urinary excretion. Sperm cells were isolated from the epididymides and the testes cells were isolated after homogenisation. In vitro, the sperm and testes cells were incubated with increasing concentrations of FeCl2 ranging from 0 to 600 microM. The median (range) levels of 8-oxodG/10(5) dG in the epididymal sperm cells increased from 0.48 (0.42-0.90) to 15.1 (11.4-17.6) (p < 0.05), whereas the level rose from 0.63 (0.22-0.81) to 8.8 (4.5-11.6) (p < 0.05) at 0 and 600 microM, respectively, in the testicular cells. In vivo groups of 7-8 rats received 0, 200 or 400 mg iron/kg as dextran i.p. After 24 h, epididymal sperm cells, testes, kidneys and liver were collected for analysis. Kidney and sperm DNA showed a significant increase in 8-oxodG in the iron-treated animals. The median (range) values of the 8-oxodG/10(5) dG in the epididymal sperm cells rose from 0.66 (0.38-1.09) to 1.12 (0.84-5.88) (p < 0.05) at 0 and 400 mg iron/kg, respectively, whereas the values in the testes and liver showed no significant change. In the kidneys the 8-oxodG/10(5) dG median (range) values were 0.98 (0.73-1.24), 1.21 (1.13-1.69) and 1.34 (1.12-1.66) after 0, 200 and 400 mg iron/kg, respectively (p < 0.05). The 8-oxodG-excretion rate was measured in 24h urine before and after iron treatment. The rate of urinary 8-oxodG excretion increased from 129 (104-179) pmol/24 h before treatment to 147 (110-239) pmol/24 h after treatment in the group receiving 400 mg iron/kg (p < 0.05). The results indicate that acute iron intoxication may increase oxidative damage to sperm and kidney DNA.     

Hemorrhagic disease in deer in Arizona

Two mule deer (Odocoileus hemionus) and one white-tailed deer (Odocoileus virginianus) in Arizona (USA) were submitted for necropsy. Gross and microscopic lesions compatible with hemorrhagic disease (HD) were observed in all three deer. Epizootic hemorrhagic disease virus type 2 (EHDV-2) was isolated from two of the deer. To our knowledge, this is the first documentation of HD in deer in Arizona. Two of the mortalities were attributed to EHDV-2 infection.     

Respiratory nematodiases in raptors in Quebec

This is a retrospective study on wild raptors submitted to the Université de Montréal (Quebec, Canada) from 1989 to 1996. Cyathostoma spp. (Nematoda: Syngamidae) adults and/or eggs were found in air sacs, lungs, bronchi, and trachea of 12 raptors (Falconiformes and Strigiformes) from Quebec, Canada, belonging to eight different species, five of which are first host records for this parasite: barred owl (Strix varia), snowy owl (Nyctea scandiaca), northern harrier (Circus cyaneus), northern goshawk (Accipiter gentilis), and broad-winged hawk (Buteo platypterus). The infection was considered fatal in four birds, while no significant clinical signs were observed in the other cases. Major pathologic changes included diffuse pyogranulomatous air sacculitis, pneumonia, and bronchitis. A few unidentified larval nematodes embedded in a granuloma were found in the lungs of an additional Coopers' hawk (Accipiter cooperii); they were not considered clinically significant. A dead nematode, surrounded by necrotic inflammatory cells, was found in the air sac of a northern goshawk. The presence of nematodes in air sacs or lungs should be considered in wild raptors demonstrating respiratory problems.     

Cycles in voles and small game in relation to variations in plant production indices in Northern Sweden

Population dynamics for voles (Cricetidae), Tengmalm's owl (Aegolius funereus (L.)), red fox (Vulpes vulpes (L.)) willow grouse (Lagopus lagopus (L.)), black grouse (Lyrurus tetrix (L.)), capercaillie (Tetrao urogallus L.), hazel hen (Tetrastes bonasia (L.)), mountain hare (Lepus timidus L.) and tularemia (Francisella tularensis (McCoy & Chapin)) and game bird recruitment were studied by index methods in northern Sweden. In addition contemporary temperature records and spruce (Picea abies (L.) Karst.) and pine (Pinus silvestris L.) cone crops (as indices for plant production) and the occurrence of forest damage, caused by voles eating bark, were studied.During 1970–80 two synchronous 4-year cycles were observed for voles, predators (Tengmalm's owl and red fox) and their alternative prey species (grouse and mountain hare). In grouse the change of numbers was correlated with that of recruitment. Autumn vole numbers peaked about a year before the other species and extensive forest damage occurred at winter peak densities of voles. These population fluctuations are consistent with a predator-prey model for their regulation. In short the model suggests that vole-food plant interactions trigger the cycle of voles, that voles generate the cycle of predators and that these in turn synchronize alternative prey populations to the others at vole declines.For voles, grouse and red fox the amplitude was higher in the first cycle compared to the second one whilst the opposite was true for the mountain hare. Although temperature and cone crops showed large interannual variations they still implied that herbivore food conditions were better during the former cycle. Hence, the reduction of the amplitude of the vole cycle may be explained by inter-cyclic differences in plant food conditions, implying food shortage (as indicated by bark-eating) at different population levels. The similar decrease of grouse and red fox populations may also be explained by deteriorated food conditions and/or for the fox by an outbreak of sarcoptic mange (Sarcoptes scabiae var. vulpes). The increased amplitude of the mountain hare cycle was part of a long-term rise in numbers after a tularemia epidemic in 1967. This is interpreted as a recovery, probably towards the generally higher pre-epidemic population level.     

Deficiencies in pro-thyrotropin-releasing hormone processing and abnormalities in thermoregulation in Cpefat/fat mice

Cpe(fat/fat) mice are obese, diabetic, and infertile. They have a mutation in carboxypeptidase E (CPE), an enzyme that converts prohormone intermediates to bioactive peptides. The Cpe(fat) mutation leads to rapid degradation of the enzyme. To test whether pro-thyrotropin-releasing hormone (TRH) conversion to TRH involves CPE, processing was examined in the Cpe(fat/fat) mouse. Hypothalamic TRH is depressed by at least 75% compared with wild-type controls. Concentrations of pro-TRH forms are increased in homozygotes. TRH-[Gly(4)-Lys(5)-Arg(6)] and TRH-[Gly(4)-Lys(5)] represent approximately 45% of the total TRH-like immunoreactivity in Cpe(fat/fat) mice; they constitute approximately 1% in controls. Levels of TRH-[Gly(4)] were depressed in homozygotes. Because the hypothalamus contains some TRH, another carboxypeptidase must be responsible for processing. Immunocytochemical studies indicate that TRH neurons contain CPE- and carboxypeptidase D-like immunoreactivity. Recombinant CPE or carboxypeptidase D can convert synthetic TRH-[Gly(4)-Lys(5)] and TRH-[Gly(4)-Lys(5)-Arg(6)] to TRH-[Gly(4)]. When Cpe(fat/fat) mice are exposed to cold, they cannot maintain their body temperatures, and this loss is associated with hypothalamic TRH depletion and reduction in thyroid hormone. These findings demonstrate that the Cpe(fat) mutation can affect not only carboxypeptidase activity but also endoproteolysis. Because Cpe(fat/fat) mice cannot sustain a cold challenge, and because alterations in the hypothalamic-pituitary-thyroid axis can affect metabolism, deficits in pro-TRH processing may contribute to the obese and diabetic phenotype in these mice.     

Down-regulation of mitofusin-2 expression in cardiac hypertrophy in vitro and in vivo

Mitofusin-2 (Mfn2) suppresses smooth muscle cell proliferation through inhibition of the Ras-extracellular signal-regulated kinases (ERK1/2) pathway. Since the ERK1/2 pathway is implicated in mediating hypertrophic signaling, we studied the changes in Mfn2 in cardiac hypertrophy using in vitro and in vivo models. Phenylephrine was used to induce hypertrophy in neonatal rat ventricular myocytes (NRVMs). In vivo hypertrophy models included spontaneously hypertensive rats (SHR), pressure-overload hypertrophy by transverse aortic constriction (TAC), hypertrophy of non-infarcted myocardium following myocardial infarction (MI), and cardiomyopathy due to cardiac-restricted overexpression of beta(2)-adrenergic receptors (beta(2)-TG). We determined hypertrophic parameters and analysed expression of atrial natriuretic peptide (ANP) and Mfn2 by real-time PCR. Phosphorylated-ERK1/2 (phospho-ERK) was measured by Western blot. Mfn2 was downregulated in phenylephrine treated NRCMs (by approximately 40%), hypertrophied hearts from SHR (by approximately 80%), mice with TAC (at 1 and 3 weeks, by approximately 50%), and beta(2)-TG mice (by approximately 20%). However, Mfn2 was not downregulated in hypertrophied hearts with 15 weeks of TAC, nor in hypertrophied non-infarcted myocardium following MI. phospho-ERK1/2 was increased in hypertrophied myocardium at 1 week post-TAC, but not in non-infarcted myocardium after MI, indicating that downregulated Mfn2 may be accompanied by an increase of phospho-ERK1/2. This study shows, for the first time, downregulated Mfn2 expression in hypertrophied hearts, which depends on the etiology and time course of hypertrophy. Further study is required to examine the causal relationship between Mfn2 and cardiac hypertrophy.     

Colicinogeny in Salmonella serovars isolated in Brazil

A study of colicinogeny was made in 748 strains of Salmonella (97 serovars) isolated from different sources: human (291), animal (119), environmental (141), food (102) and animal feed (95). Colicin production was detected in 64 strains (8.6%), particularly isolated from foods (30.4%). Col E1 (53) and Ia (44) were the most frequently observed, especially in S. agona for environment and food sources. Col V production was identified in 5 strains of S. typhimurium within 8 producer cultures isolated from humans. Its relationship with the sources and serovars of Salmonella are discussed.     

Trends in leaf photosynthesis in historical rice varieties developed in the Philippines since 1966

Crop improvement in terms of yield is rarely linked to leaf photosynthesis. However, in certain crop plants such as rice, it is predicted that an increase in photosynthetic rate will be required to support future grain yield potential. In order to understand the relationships between yield improvement and leaf photosynthesis, controlled environment conditions were used to grow 10 varieties which were released from the International Rice Research Institute (IRRI) between 1966 and 1995 and one newly developed line. Two growth light intensities were used: high light (1500 micromol m(-2) s(-1)) and low light (300 micromol m(-2) s(-1)). Gas exchange, leaf protein, chlorophyll, and leaf morphology were measured in the ninth leaf on the main stem. A high level of variation was observed among high light-grown plants for light-saturated photosynthetic rate per unit leaf area (P(max)), stomatal conductance (g), content of ribulose bisphosphate carboxylase-oxygenase (Rubisco), and total leaf protein content. Notably, between 1966 and 1980 there was a decline in P(max), g, leaf protein, chlorophyll, and Rubisco content. Values recovered in those varieties released after 1980. This striking trend coincides with a previous published observation that grain yield in IRRI varieties released prior to 1980 correlated with harvest index whereas that for those released after 1980 correlated with biomass. P(max) showed significant correlations with both g and Rubisco content. Large differences were observed between high light- and low light-grown plants (photoacclimation). The photoacclimation 'range' for P(max) correlated with P(max) in high light-grown plants. It is concluded that (i) leaf photosynthesis may be systematically affected by breeding strategy; (ii) P(max) is a useful target for yield improvements where yield is limited by biomass production rather than partitioning; and (iii) the capacity for photoacclimation is related to high P(max) values.     

Mycobacterium bovis in wildlife in France

In early 2001, tuberculosis-like lesions were detected in three hunter-killed red deer (Cervus elaphus) in the Brotonne Forest (Normandy, France), and Mycobacterium bovis was isolated. In subsequent hunting seasons, two surveys were conducted in the area. In the first survey (2001-02 hunting season), nine (13%) of 72 red deer sampled were positive for M. bovis. In the 2005-06 hunting season, the prevalence of M. bovis infection increased to 24% (chi2=3.85, df=1, P=0.05; 33 positive among 138 sampled). The prevalence remained stable in juveniles, but it increased significantly in adults: from 13% in 2001-02 to 32% in 2005-06 (chi2=5.13, df=1, P=0.02). Wild boar (Sus scrofa) were heavily infected in both surveys. One roe deer (Capreolus capreolus) and one red fox (Vulpes vulpes) also tested positive in the second survey. Mycobacterium bovis was not isolated from Eurasian badgers (Meles meles). Spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat analysis demonstrated that all M. bovis strains isolated from wildlife were of the same genotype. Thus, the wildlife outbreak involved only a single strain, and this strain was the same as that circulating in nearby cattle herds since 1995. Sensitivity, specificity, and predictive values of the presence of macroscopic lesions as a diagnostic criterion were evaluated from the data obtained from red deer. Necropsy seems to be satisfactory as a routine tool to monitor the disease in wild red deer populations in which bovine tuberculosis has become established.     

Spontaneous contractions in elasmobranch vessels in vitro

Isolated vessels from four elasmobranchs, yellow stingray (Urolophus jamaicensis), clearnose skate (Raja eglanteria), ghost shark (Hydrolagus novaezelandiae), and spiny dogfish (Squalus acanthias), were examined for the presence of spontaneous contractions (SC). SC were observed in otherwise unstimulated dorsal aortas (DA) from stingray and ghost shark, but not in skate DA. Unstimulated ventral aortas (VA) did not exhibit SC. After treatment of VA with a contractile agonist, SC appeared in stingray and skate but not ghost shark or dogfish. SC in stingray VA were subsequently inhibited by either epinephrine (10(-5) M) or indomethacin (10(-4) M). Agonist contraction also elicited strong SC in ductus Cuvier from stingray, but not from ghost shark or dogfish. SC in dogfish hepatic portal veins (HPV) produced a rhythmical oscillation in tension. The frequency of HPV SC was highest (approximately 1 min(-1)) in intact veins and lower (approximately 3 min(-1)) in vein segments, indicative of a dominant pacemaker in the intact vessel. SC in HPV were depressed during the first 30 min of hypoxia, but there was substantial recovery over an additional 30 min of hypoxia and complete recovery upon return to normoxia. Addition of 80 mM KCl completely inhibited HPV SC and lowered resting tone. These results show that SC are a common feature of elasmobranch vessels and there appears to be a correlation between swimming behavior and the propensity for SC. KCl inhibition of SC and tonus in HPV is highly unusual for vascular smooth muscle.     

Basidioboliasis in anurans in Florida

Members of the genus Basidiobolus, a saprophytic fungus, have been associated with the digestive tracts of a wide variety of amphibians and reptiles. To elucidate the relationship of Basidiobolus sp. with amphibians in central Florida (USA), we document the occurrence of the fungus in the digestive tracts of Bufo terrestris, Buffo quercicus, Hyla femoralis, Hyla cinerea, Hyla gratiosa, Hyla squirella, Osteopilus septentrionalis, and Rana utricularia. Species that occupy terrestrial habitats (B. terrestris, B. quercicus, and R. utricularis) were found to harbor Basidiobolus spp. more frequently (83, 78, and 91%, respectively) than those that occupied a more arboreal habitat (H. cinerea, H. squirella, H. femoralis, H. gratiosa, and O. septentrionalis (50, 56, 55, 56, and 70%, respectively).