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101.
The latent toxoplasmosis is usually considered to be asymptomatic, however, this paradigm has never been rigorously tested. Here we searched for symptoms of deterioration of physical health (decrease of weight) in infected people by analysis of clinical records of 758 women tested for toxoplasmosis in the 16th week of gravidity. Toxoplasma-positive women have a lower body weight in the 16th week of gravidity (p = 0.02) than Toxoplasma-negative women. Moreover, a negative correlation between weight and the duration of toxoplasmosis was found in a subset of 174 Toxoplasma-positive women (p = 0.04), suggesting that slow and cumulative effects of latent toxoplasmosis, rather than a transient effect of acute toxoplasmosis, are responsible for the decreased weight of infected subjects. Longer duration of gravidity estimated from the date of last menstruation in the set of Toxoplasma-positive women in the 16th week of gravidity estimated with ultrasonography (p = 0.04) suggests a possibility of retarded foetal growth in Toxoplasma-positive women. The prevalence of latent toxoplasmosis is extremely high. Therefore, even its mild symptoms such as the decreased body weight in Toxoplasma-positive pregnant women might in fact indicate an unrecognized serious public health problem. 相似文献
102.
Results of clinical and laboratory examination of animals experimentally infected with Taenia saginata eggs are described. At the early stage of infection, increased temperature, cough, muscle shaking and unstable pace were observed. The locomotive disorders disappeared only on day 50 p.i. Leukocytosis and peripheric eosinophilia were found at the early stage of infection. On days 14-28 p.i. the activity of serum creatine-kinase (CK) significantly increased. The activity of other enzymes (AST, ALT, LD, ALP and ALD) examined was increased only slightly and irregularly. The lipid content in blood serum markedly increased on days 9-16 p.i. 相似文献
103.
At cattle overwintering areas, inputs of nutrients in animal excrements create conditions favourable for intensive microbial
activity in soil. During nitrogen transformations, significant amounts of N2O are released, which makes overwintering areas important sources of N2O emission. In previous studies, however, increasing intensity of long-term cattle impact did not always increase emissions
of N2O from the soil: in some cases, N2O emissions from the soil were lower at the most impacted area than at the moderately impacted one. Thus, the relationships
between the level of long-term animal impact and potential production of N2O from soil by denitrification were investigated in field and laboratory experiments. Field measurements indicated that the
production of N2O after glucose and nitrate amendments was greater in severely and moderately impacted locations than in an unimpacted location,
while differences between the severely and moderately impacted locations were not significant. In laboratory experiments,
the potential production of N2O (measured as anaerobic production of N2O after addition of glucose and nitrate) was highest in the moderately impacted soil. Surprisingly, potential N2O production was lower in the most impacted than in the moderately impacted soil, and the net N2O production in the highly impacted soil was further decreased by a significant reduction of N2O to N2. The expected stimulating effect of an increasing ratio of glucose C to nitrate N on the reduction of N2O to N2 during denitrification was not confirmed. The results show that cattle increase the denitrification potential of the soil
but suggest that the denitrification potential does not increase indefinitely with increasing cattle impact. 相似文献
104.
Litter decomposing basidiomycetous fungi produce ligninolytic oxidases and peroxidases which are involved in the transformation of lignin, as well as humic and fulvic acids. The aim of this work was to evaluate their importance in lignin transformation in forest litter. Two litter decomposing basidiomycete species differing in their abilities to degrade lignin - Hypholoma fasciculare, and Gymnopus erythropus - were cultured on sterile or non-sterile oak litter and their transformation of a 14C-labelled synthetic lignin (dehydrogenation polymer 14C-DHP) was compared with that of the indigenous litter microflora. Both in sterile and non-sterile litter, colonisation by basidiomycetes led to higher titres of lignocellulose-degrading enzymes, in particular of laccase and Mn-peroxidase (MnP). The titres of the latter were 6 to 40-fold increased in the presence of basidiomycetes compared to non-sterile litter. During 10 weeks, G. erythropus mineralised over 31% of 14C-DHP in sterile litter and 23% in non-sterile litter compared to 14% in the non-sterile control. Lignin mineralization by H. fasciculare was comparable to the non-sterile control, 12% in sterile litter and 16% in the non-sterile litter. The largest part of 14C from 14C-DHP was transformed into humic compounds during litter treatment with both fungi as well as in the control. In addition to the fast lignin mineralization, microcosms containing G. erythropus also showed a lower final content of unaltered lignin and 23-28% of the lignin was converted into water-soluble compounds with relatively low molecular mass (<5 kDa). Both G. erythropus and H. fasciculare were also able to further mineralise humic compounds. During a 10-week fungal treatment of an artificial 14C-humic acid (14C-HA) supplemented to the natural humic material of a forest soil, the fungi mineralised 42% and 19% of the labelled material, respectively, under sterile conditions. The 14C-HA mineralization by introduced basidiomycetes in microcosms containing non-sterile humic material, however, did not significantly differ from that of a non-sterile control and was around 12%. Altogether the results show that saprobic basidiomycetes can considerably differ in their rates of lignin and humic substance conversion. Furthermore, lignin degradation in forest soil can rather slow down by interspecific competition than it is accelerated by cooperation of different microorganisms occupying specific nutritional niches. Therefore, the overall contribution of saprobic basidiomycetes depends on their particular eco-physiological status and the competitive pressure, and may be often lower than initially expected. Significant lignin transformation including partial mineralization is seemingly not exclusively dependent on exceptional high titres of ligninolytic enzymes but also on so far unknown factors. Higher endocellulase production and subsequent weight loss was found in microcosms where saprobic basidiomycetes were combined with indigenous microbes. Potentially, lignin degradation by the basidiomycetes may have increased cellulose availability to the indigenous microbes. 相似文献
105.
The serine protease TMPRSS6 is required to sense iron deficiency 总被引:1,自引:0,他引:1
Du X She E Gelbart T Truksa J Lee P Xia Y Khovananth K Mudd S Mann N Moresco EM Beutler E Beutler B 《Science (New York, N.Y.)》2008,320(5879):1088-1092
106.
- 1. Crucian carp Carassius carassius, which is native to south‐east England, has received little previous study in Britain but is threatened by introductions of goldfish Carassius auratus through hybridization and by frequent mis‐identification of brown goldfish as crucian carp. The present study provides the first data on back‐calculated growth, morphology and age‐at‐maturity of crucian carp in Britain.
- 2. The youngest mature crucian were female (age 2+), the smallest mature crucian were male (age 3+), with almost all fish mature at age 3+. Sex dimorphism in back‐calculated standard length at age was not observed except at age 2+ (juveniles longest). Shifts in morphological characters often associated with maturation (dorsal and ventral fin length, dorsal and anal fin depth, pre‐dorsal distance, body width) were observed between ages 4+ and 7+, which (in contrast to the relatively abrupt shift in maturity) suggests that age and size at maturation may not reflect the size and age of active (i.e. real) spawning.
- 3. Back‐calculated standard lengths at age for crucian carp were intermediate relative to other European populations, indicating that environmental conditions in England appear to be well suited to the species despite being at the westernmost extent of the species' native European range. The management of ornamental ponds specifically for crucian carp is discussed.