Partial substitution of NO(3)(-) by NH(4)(+) fertilization increases ammonium assimilating enzyme activities and reduces the deleterious effects of salinity on the growth of barley

Productivity of cereal crops is restricted in saline soils but may be improved by nitrogen nutrition. In this study, the effect of ionic nitrogen form on growth, mineral content, protein content and ammonium assimilation enzyme activities of barley (Hordeum vulgare cv. Alexis L.) irrigated with saline water, was determined. Leaf and tiller number as well as plant fresh and dry weights declined under salinity (120 mM NaCl). In non-saline conditions, growth parameters were increased by application of NH(4)(+)/NO(3)(-) (25:75) compared to NO(3)(-) alone. Under saline conditions, application of NH(4)(+)/NO(3)(-) led to a reduction of the detrimental effects of salt on growth. Differences in growth between the two nitrogen regimes were not due to differences in photosynthesis. The NH(4)(+)/NO(3)(-) regime led to an increase in total N in control and saline treatments, but did not cause a large decrease in plant Na(+) content under salinity. Activities of GS (EC 6.3.1.2), GOGAT (EC 1.4.1.14), PEPC (EC 4.1.1.31) and AAT (EC 2.6.1.1) increased with salinity in roots, whereas there was decreased activity of the alternative ammonium assimilation enzyme GDH (EC 1.4.1.2). The most striking effect of nitrogen regime was observed on GDH whose salinity-induced decrease in activity was reduced from 34% with NO(3)(-) alone to only 14% with the mixed regime. The results suggest that the detrimental effects of salinity can be reduced by partial substitution of NO(3)(-) with NH(4)(+) and that this is due to the lower energy cost of N assimilation with NH(4)(+) as opposed to NO(3)(-) nutrition.     

High-temperature biotrickling filtration of hydrogen sulphide

Biofiltration of malodorous reduced sulphur compounds such as hydrogen sulphide has been confined to emissions that are at temperatures below 40°C despite the fact that there are many industrial emissions (e.g. in the pulp and paper industry) at temperatures well above 40°C. This paper describes our study on the successful treatment of hydrogen sulphide gas at temperatures of 40, 50, 60 and 70°C using a microbial community obtained from a hot spring. Three biotrickling filter (BTF) systems were set up in parallel for a continuous run of 9 months to operate at three different temperatures, one of which was always at 40°C as a mesophilic control and the other two were for exploring high-temperature operation up to 70°C. The continuous experiment and a series of batch experiments in glass bottles (250 ml) showed that addition of glucose and monosodium glutamate enhanced thermophilic biofiltration of hydrogen sulphide gas and a removal rate of 40 g m⁻³ h⁻¹ was achieved at 70°C. We suggest that the glucose is acting as a carbon source for the existing microbial community in the BTFs, whereas glutamate is acting as a compatible solute. The use of such organic compounds to enhance biodegradation of hydrogen sulphide, particularly at high temperatures, has not been demonstrated to our knowledge and, hence, has opened up a range of possibilities for applying biofiltration to hot gas effluent.     

The potential influence of the heel counter on internal stress during static standing: a combined finite element and positional MRI investigation

Confinement of the heel due to the counter of the shoe is believed to influence heel pad biomechanics. Using a two-dimensional finite element model of the heel pad and shoe during a simulation of static standing, the aim of this study was to quantify the potential effect of confinement on internal heel pad stress. Non-weightbearing MRI and weightbearing MRI with plantar pressure and ground reaction force data were recorded for a single subject. The non-weightbearing MRI was used to create two FE models of the heel pad, using either homogeneous or composite material properties. The composite model included a distinction in material properties between fat pad and skin. Vertical and medial-lateral forces, as measured on the subject's heel, were applied to the models and vertical compressive strains for both models were comparable with those observed by weightbearing MRI. However, only for the composite model was the predicted plantar pressure distribution comparable with measured data. The composite model was therefore used in further analyses. In this composite model, the internal stresses were located mainly in the skin and were predominantly tensile in nature, whereas the stress state in the fat pad approached hydrostatic conditions. A representation of a running shoe, including an insole, midsole and heel counter was then added to the composite heel pad to form the shod model. In order to investigate the counter effect, the load was applied to the shod model with and without the heel counter. The effect of the counter on peak stress was to elevate compression (0-50%), reduce tension (22-34%) and reduce shear (22-28%) in the skin. In addition, the counter reduced both compressive (20-40%) and shear (58-80%) stress in the fat pad and tension in the fat pad remained negligible. Taken together the results indicate that a well-fitted counter works in sympathy with the internal structure of the heel pad and could be an effective reducer of heel pad stress. However, further research needs to be undertaken to assess the long-term effects on the soft-tissues, practicalities of achieving good fit and behavior under dynamic events.     

Human immunodeficiency virus-specific CD8+ T-cell activity is detectable from birth in the majority of in utero-infected infants

Human immunodeficiency virus (HIV)-infected infants in sub-Saharan Africa typically progress to AIDS or death by 2 years of life in the absence of antiretroviral therapy. This rapid progression to HIV disease has been related to immaturity of the adaptive immune response in infants. We screened 740 infants born to HIV-infected mothers and tracked development and specificity of HIV-specific CD8⁺ T-cell responses in 63 HIV-infected infants identified using gamma interferon enzyme-linked immunospot assays and intracellular cytokine staining. Forty-four in utero-infected and 19 intrapartum-infected infants were compared to 45 chronically infected children >2 years of age. Seventy percent (14 of 20) in utero-infected infants tested within the first week of life demonstrated HIV-specific CD8⁺ T-cell responses. Gag, Pol, and Nef were the principally targeted regions in chronic pediatric infection. However, Env dominated the overall response in one-third (12/36) of the acutely infected infants, compared to only 2/45 (4%) of chronically infected children (P = 0.00083). Gag-specific CD4⁺ T-cell responses were minimal to undetectable in the first 6 months of pediatric infection. These data indicate that failure to control HIV replication in in utero-infected infants is not due to an inability to induce responses but instead suggest secondary failure of adaptive immunity in containing this infection. Moreover, the detection of virus-specific CD8⁺ T-cell responses in the first days of life in most in utero-infected infants is encouraging for HIV vaccine interventions in infants.     

Isoproterenol hydrochloride augments collagen proliferation and ATPase activity in mice soleus and EDL muscles

Aim of this study is to analyze the effect of chronic administration of beta agonist isoproterenol hydrochloride (60 mg kg(-1) day(-1); 30 days) on soleus (a slow type) and extensor digitorum longus (EDL, a fast type) muscles in young mice. Isoproterenol resulted in significant increase in muscle weight to whole body weight ratio with no increase in hypertrophy index in soleus muscle. A significant increase in noncontractile protein collagen is also observed in both muscles but more prominent in soleus muscle. Collagen proliferation is also analyzed on sodium dodecyle sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of pepsin soluble and Cyanogen Bromide (CN Br) treated pepsin insoluble collagen. Isoproterenol remolded the myofibrillar proteins in both muscles but significant increase in myofibrillar ATPase activity occurred only in soleus muscle. It is concluded that growth stimulatory effect of isoproterenol hydrochloride is more prominent in soleus than FDL muscle. Isoproterenol augmented the proliferation of non-contractile protein collagen in soleus and EDL muscles. The transformation in myofibrillar proteins caused by isoproterenol might lead to an enhancement of contractile performance.     

Frequency of infection with A and B supergroup <Emphasis Type="Italic">Wolbachia</Emphasis> in insects and pests associated with mulberry and silkworm

Wolbachia is a ubiquitous, Gram-negative, vertically transmitted, alpha-proteobacterium that causes an array of reproductive abnormalities including cytoplasmic incompatibility, feminization of genetic males, parthenogenesis in a number of insect species, among others. Wolbachia is now being exploited as an agent for pest and vector control. Previous surveys indicated that it is commonly seen in 16–76% of arthropods. In this paper, using polymerase chain reaction assay based on specific amplification of the ftsZ-A and-B supergroup Wolbachia gene fragments, we found that 30% of insects and pests screened were positive for Wolbachia. Among them 66.7% harbour double Wolbachia infection, while 33.3% harbour single Wolbachia infection. These results indicate widespread infection with both double and single Wolbachia, and provide a wealth of information to exploit this endobacterium for the management of pests and vectors.     

GDI-1 phosphorylation switch at serine 96 induces RhoA activation and increased endothelial permeability

We identified the GDI-1-regulated mechanism of RhoA activation from the Rho-GDI-1 complex and its role in mediating increased endothelial permeability. Thrombin stimulation failed to induce RhoA activation and actin stress fiber formation in human pulmonary arterial endothelial cells transduced with full-length GDI-1. Expression of a GDI-1 mutant form (C-GDI) containing the C terminus (aa 69 to 204) also prevented RhoA activation, whereas further deletions failed to alter RhoA activation. We observed that protein kinase Calpha-mediated phosphorylation of the C terminus of GDI-1 at Ser96 reduced the affinity of GDI-1 for RhoA and thereby enabled RhoA activation. Rendering GDI-1 phosphodefective with a Ser96 --> Ala substitution rescued the inhibitory activity of GDI-1 toward RhoA but did not alter the thrombin-induced activation of other Rho GTPases, i.e., Rac1 and Cdc42. Phosphodefective mutant GDI-1 also suppressed myosin light chain phosphorylation, actin stress fiber formation, and the increased endothelial permeability induced by thrombin. In contrast, expressing the phospho-mimicking mutant S96D-GDI-1 protein induced RhoA activity and increased endothelial permeability independently of thrombin stimulation. These results demonstrate the crucial role of the phosphorylation of the C terminus of GDI-1 at S96 in selectively activating RhoA. Inhibiting GDI-1 phosphorylation at S96 is a potential therapeutic target for modulating RhoA activity and thus preventing the increase in endothelial permeability associated with vascular inflammation.     

Effect of seed soaking with sulphydryl compounds on the photochemical efficiency and antioxidant defence system during the growth of pearl millet under water limiting environment

Pearl millet (Pennisetum glaucum L. cv. HHB-67) seeds were pre-soaked in sulphydryl compounds (dithiothreitol, thioglycollic acid, thiourea, and cysteine). In plants at 59 and 67 d after sowing (DAS), activities of photosystem (PS) 2 (ferricyanide site) and PS1, both chloroplastic and total superoxide dismutase, glutathione reductase, and glutathione-S-transferase increased after all sulphydryl pre-treatments at both stages of plant development. Also dry matter of plant parts sampled at 55 DAS was higher after thiol-treatments in comparison with control.