Differential inactivation of seed exudate stimulation of Pythium ultimum sporangium germination by Enterobacter cloacae influences biological control efficacy on different plant species

This study was initiated to understand whether differential biological control efficacy of Enterobacter cloacae on various plant species is due to differences in the ability of E. cloacae to inactivate the stimulatory activity of seed exudates to Pythium ultimum sporangium germination. In biological control assays, E. cloacae was effective in controlling Pythium damping-off when placed on the seeds of carrot, cotton, cucumber, lettuce, radish, tomato, and wheat but failed to protect corn and pea from damping-off. Seeds from plants such as corn and pea had high rates of exudation, whereas cotton and cucumber seeds had much lower rates of exudation. Patterns of seed exudation and the release of P. ultimum sporangium germination stimulants varied among the plants tested. Seed exudates of plants such as carrot, corn, lettuce, pea, radish, and wheat were generally more stimulatory to P. ultimum than were the exudates of cotton, cucumber, sunflower, and tomato. However, this was not directly related to the ability of E. cloacae to inactivate the stimulatory activity of the exudate and reduce P. ultimum sporangium germination. In the spermosphere, E. cloacae readily reduced the stimulatory activity of seed exudates from all plant species except corn and pea. Our data have shown that the inability of E. cloacae to protect corn and pea seeds from Pythium damping-off is directly related to its ability to inactivate the stimulatory activity of seed exudates. On all other plants tested, E. cloacae was effective in suppressing damping-off and inactivating the stimulatory activity of seed exudates.     

Effects of secretory leukocyte protease inhibitor on the tumor necrosis factor-alpha production and NF-kappaB activation of lipopolysaccharide-stimulated macrophages

It has been reported that lipopolysaccharide (LPS)-hyporesponsiveness of macrophages (Mphis) of C3H/HeJ mice with a mutated Lps gene (Lps(d)) is related to high-level expression of secretory leukocyte protease inhibitor (SLPI) in response to LPS, causing suppression of NF-kappaB activation and tumor necrosis factor-alpha (TNF-alpha) production. We thus examined the effects of SLPI on the TNF-alpha production by LPS-stimulated Mphis. Neither intact SLPI nor half-sized SLPI (1/2 SLPI) down-regulated Mphi TNF-alpha production. 1/2 SLPI weakly increased Mphi TNF-alpha production in response to LPS signaling and potentiated the LPS-induced activation of NF-kappaB, especially the binding of p65-p50 heterodimers to the DNA kappaB sites, suggesting that LPS-hyporesponsiveness of Lps(d) Mphis is not due to the overexpression of SLPI.     

Defective brain development in mice lacking the Hif-1alpha gene in neural cells

Hypoxia-inducible factor 1alpha (HIF-1alpha) is essential for vascular development during embryogenesis and pathogenesis. However, little is known about its role in brain development. To investigate the function of HIF-1alpha in the central nervous system, a conditional knockout mouse was made with the Cre/LoxP system with a nestin promoter-driven Cre. Neural cell-specific HIF-1alpha-deficient mice exhibit hydrocephalus accompanied by a reduction in neural cells and an impairment of spatial memory. Apoptosis of neural cells coincided with vascular regression in the telencephalon of mutant embryos, and these embryonic defects were successfully restored by in vivo gene delivery of HIF-1alpha to the embryos. These results showed that expression of HIF-1alpha in neural cells was essential for normal development of the brain and established a mouse model that would be useful for the evaluation of therapeutic strategies for ischemia, including hypoxia-mediated hydrocephalus.     

Tissue distribution,molecular cloning,and gene expression of cytosolic glutathione peroxidase in Japanese monkey

Cytosolic glutathione peroxidase (GPX-1) is an important antioxidant enzyme that scavange hydrogen peroxide in mammalian cells. The level of GPX-1 activity in Japanese monkey (Macaca fuscata) tissues was determined and it was found to be high in the liver, kidney, and adrenal gland followed by the small intestine. We also cloned the GPX-1 cDNA that included the whole protein-coding region. The active-site selenocysteine was assumed to be encoded by a TGA codon. Compared to the GPX-1s of other mammalian species, essential residues in catalysis were well conserved in monkey GPX-1. Amino acid substitutions were frequent in the N- and C-terminal regions which are less essential in catalysis. Expression of GPX-1 mRNA was found to be high in the liver, kidney, and adrenal gland, in consistence with the tissue distribution of GPX-1 activity.     

Hes1 is a negative regulator of inner ear hair cell differentiation

Hair cell fate determination in the inner ear has been shown to be controlled by specific genes. Recent loss-of-function and gain-of-function experiments have demonstrated that Math1, a mouse homolog of the Drosophila gene atonal, is essential for the production of hair cells. To identify genes that may interact with Math1 and inhibit hair cell differentiation, we have focused on Hes1, a mammalian hairy and enhancer of split homolog, which is a negative regulator of neurogenesis. We report here that targeted deletion of Hes1 leads to formation of supernumerary hair cells in the cochlea and utricle of the inner ear. RT-PCR analysis shows that Hes1 is expressed in inner ear during hair cell differentiation and its expression is maintained in adulthood. In situ hybridization with late embryonic inner ear tissue reveals that Hes1 is expressed in supporting cells, but not hair cells, of the vestibular sensory epithelium. In the cochlea, Hes1 is selectively expressed in the greater epithelial ridge and lesser epithelial ridge regions which are adjacent to inner and outer hair cells. Co-transfection experiments in postnatal rat explant cultures show that overexpression of Hes1 prevents hair cell differentiation induced by Math1. Therefore Hes1 can negatively regulate hair cell differentiation by antagonizing Math1. These results suggest that a balance between Math1 and negative regulators such as Hes1 is crucial for the production of an appropriate number of inner ear hair cells.     

Molecular cloning of neonate/infant-specific pepsinogens from rat stomach mucosa and their expressional change during development

To clarify the nature of rat neonate/infant-specific pepsinogens, we carried out their purification and molecular cloning. Prochymosin was found to be the major neonatal pepsinogen. The general proteolytic activity of its active form, chymosin, was, however, lower than those of pepsins A and C which are predominant in adult animals. Molecular cloning of rat prochymosin cDNA was achieved along with cDNA for another neonate-specific pepsinogen, pepsinogen F, although determination of pepsinogen F in neonatal gastric mucosa was unsuccessful, presumably due to its lack of proteolytic activity or different proteolytic specificity. Northern blot analysis confirmed that genes for prochymosin and pepsinogen F are expressed only at neonatal/infant stages and the switching of gene expression to that of pepsinogen C occurred at late infant stages. A phylogenetic tree based on nucleotide sequences showed clearly that pepsinogens fall into four major groups, namely prochymosin and pepsinogen F of the neonate/infant and pepsinogens A and C of adult animals. Although, to date, prochymosin and pepsinogen F were believed to be expressed in only a limited number of mammals, the present results suggest that they might be expressed at the neonatal/infant stage in a variety of mammals.     

Coprobacillus catenaformis gen. nov., sp. nov., a new genus and species isolated from human feces

Three strains of Eubacterium-like isolates from human feces were characterized by biochemical tests and 16S rDNA analysis. The phenotypic characteristics of the three strains resembled those of the genus Collinsella transferred from the genus Eubacterium recently. However, Eubacterium-like strains were phylogenetically members of the Clostridium subphylum of gram-positive bacteria, and these showed a specific phylogenetic association with Clostridium ramosum and C. spiroforme. C. ramosum and C. spiroforme are gram-positive, anaerobic, spore-forming bacteria that belong to the genus Clostridium, and the G + C contents are 26.0 and 27.4 mol%, respectively. However, the three Eubacterium-like strains had G + C contents of 32.1 to 33.1 mol% and were non-spore-forming rods. Based on phenotypic characteristics, we can differentiate these species, and furthermore, a 16S rDNA sequence divergence of greater than 9% with a new related genus, Coprobacillus, is proposed for the three strains, with one species, Coprobacillus catenaformis. The type strain of C. catenaformis is JCM 10604T.     

Sucrose-diet feeding induces gene expression of heat shock protein in rat brain under stress

Stress-induced hyperphagia is enhanced in the presence of sweets, particularly sucrose, which may act to attenuate stress. Recently, it was also reported that heat shock protein (HSP) may be involved in the defense against stress. To explore whether sucrose alters gene expression of HSP under stress, we determined the HSP mRNA levels in the hypothalamus, cerebellum, and cerebral cortex after restraint stress in sucrose-diet-fed rats. Competitive RT-PCR revealed that gene expressions of HSP27 in the cerebral cortex and cerebellum and of HSP70 in the cerebral cortex, hypothalamus, and cerebellum were induced by restraint stress under a sucrose-diet-fed condition. However, restraint stress by itself or sucrose diet alone did not induce expression of HSP27 or HSP70 mRNA in any of the three anatomical parts. It is suggested that sucrose facilitates the gene expression of HSP27 and HSP70 in brain after restraint stress, which may attenuate stress.     

Failure to respond to interferon-α 2a therapy is associated with increased hepatic iron levels in patients with chronic hepatitis C

Recent reports suggest the hepatic iron concentration (HIC) may influence the activity of hepatitis and the response to interferon (IFN) therapy in patients with chronic hepatitis C (CH-C). We have evaluated iron status in 28 patients with CH-C and determined if pretreatment iron status can predict the response to IFN-α therapy in these patients. Increased serum iron, transferrin saturation, and ferritin levels were observed in 3 (11%), 11 (39%), and 5 (18%) patients, respectively. Hepatic iron deposits were histologically detected in 17 (61%) patients, and 14 of them had stainable hepatocytic iron. However, all HIC values were within the normal range (203–1279 μg/g). Seven of 17 patients treated with IFN-α for 6 mo had normalization of serum transaminases and disappearance of serum HCV-RNA (responders). Nonresponders had a significantly higher median HIC compared with responders (710 vs 343 μg/g, respectively;p < 0.05). There was no significant difference in other pretreatment iron parameters, serum HCV-RNA level, or HCV-genotype between responders and nonresponders. In conclusion, mild hepatic iron accumulation occurs in patients with CH-C. Increased hepatic iron stores are associated with poor response to IFN therapy. Pretreatment HIC may be an additional host-specific parameter with a predictive value for responsiveness to IFN therapy, in addition to well-known predictive viral factors.