Nisin expression production from Lactococcus lactis in milk whey medium

BACKGROUND: Nisin is a commercially available bacteriocin produced by Lactococcus lactis ATCC 11454 and used as a natural agent in the biopreservation of food. In the current investigation, milk whey, a byproduct from dairy industries was used as a fermentation substrate for the production of nisin. Lactococcus lactis ATCC 11454 was developed in a rotary shaker (30 °C/36 h/100 rpm) using two different media with milk whey (i) without filtration, pH 6.8, adjusted with NaOH 2 mol L^?1 and without pH adjustment, both autoclaved at 121 °C for 30 min, and (ii) filtrated (1.20 µm and 0.22 µm membrane filter). These cultures were transferred five times using 5 mL aliquots of broth culture for every new volume of the respective media. RESULTS: The results showed that culture media composed of milk whey without filtration supplied L. lactis its adaptation needs better than filtrated milk whey. Nisin titers, in milk whey without filtration (pH adjusted), was 11120.13 mg L^?1 in the second transfer, and up to 1628‐fold higher than the filtrated milk whey, 6.83 mg.L^?1 obtained in the first^t transfer. CONCLUSIONS: Biological processing of milk byproducts (milk whey) can be considered a profitable alternative, generating high‐value bioproducts and contributing to decreasing river disposals by dairy industries. Copyright © 2008 Society of Chemical Industry     

Are weaning foods causing impaired iron and zinc status in 1-year-old Swedish infants? A cohort study

Retrobulbar hematoma is a rare complication of blunt periorbital trauma with the potential disastrous consequence of visual impairment and blindness. The preoperative assessment, diagnostic symptoms and signs, as well as the treatment of this condition are reviewed. The patients presented as well as a review of the literature confirm that although retrobulbar hematoma is a rare complication of blunt periorbital trauma, irreversible visual sequelae can be prevented by prompt diagnosis and immediate surgical and pharmacological therapy.     

The effect of 9-beta-D-arabinofuranosyl-2-fluoroadenine and 1-beta-D-arabinofuranosylcytosine on the cell cycle phase distribution, topoisomerase II level, mitoxantrone cytotoxicity, and DNA strand break production in K562 human leukemia cells

The UvrA and UvrB proteins form part of the UvrABc endonuclease, which is responsible for nucleotide excision repair in Escherichia coli. Using a mobility shift gel assay we have studied the binding of UvrA dimer, UvrB monomer and UvA(2)B trimer complexes with 40, 50 and 136 bp (32)P-end-labelled DNA fragments adducted with aflatoxin B(1). UvrA was shown to re-associate with adduct specific UvrB: DNA complexes, a phenomenon which could be reversed by the addition of 500 mM potassium chloride or anti-UvrA anti-sera. Re-association was shown to be UvrA concentration dependent. Re-association of UvrA(2)B to the UvrB:DNA complex was not seen. We have also shown that the UvrB:DNA complex, in the case of aflatoxin B(1), is extremely stable with a half-life excess of 400 min and that fragment termini are not a specific substrate for UvrA binding.     

Binding of human single chain urokinase to Chinese Hamster Ovary cells and cloning of hamster u-PAR

In the present study, we assessed oxidative stress in patients with dilated cardiomyopathy of ischemic or idiopathic etiology. For this reason we measured whole blood reduced glutathione, erythrocyte superoxide dismutase, susceptibility of erythrocyte membranes and erythrocytes to peroxidation, and SH content of erythrocyte membranes in 12 patients (8 men and 4 women, ages 31 to 66 years) with idiopathic dilated cardiomyopathy, in 11 patients (8 men and 3 women, ages 32 to 65 years) with ischemic dilated cardiomyopathy, and in 21 healthy volunteers (12 men and 9 women, ages 25 to 67 years). There was no statistically significant difference between the two patient groups for the indicators studied (P >0.05). Blood glutathione, erythrocyte superoxide dismutase, and membrane SH content of both groups of patients was decreased compared with controls (P <0.05), whereas erythrocyte and membrane susceptibility to peroxidation were increased (P <0.05). We conclude that patients with idiopathic or ischemic dilated cardiomyopathy exhibit abnormalities of a range of markers of increased oxidative stress. These abnormalities may contribute to contractile dysfunction, increased incidence of fatal arrhythmias, and sudden death.     

Nucleoside-diphosphate kinase-mediated signal transduction via histidyl-aspartyl phosphorelay systems in Escherichia coli

Nucleoside-diphosphate kinase (NDP kinase), a key enzyme in nucleotide metabolism, is also known to be involved in growth and developmental control and tumor metastasis suppression. Interestingly, we find that coexpression of NDP kinase with Taz1, a Tar/EnvZ chimera, in the absence of its native signal, can activate a porin gene ompC-lacZ expression in Escherichia coli. Further studies show that NDP kinase can act as a protein kinase to phosphorylate histidine protein kinases such as EnvZ and CheA which are members of the His-Asp phosphorelay signal transduction systems in E. coli. Instead of ATP, the exclusive phosphodonor for histidine kinases, GTP can be utilized in vitro in the presence of NDP kinase to phosphorylate EnvZ and CheA, which then transfer the phosphoryl group to OmpR and CheY, the respective response regulators. The direct involvement of GTP for the phosphorylation of EnvZ through NDP kinase was further demonstrated by the use of a mutant EnvZ, which lost ability to be autophosphorylated with ATP. Phospho-OmpR thus formed can bind specifically to an ompF promoter sequence. These results suggest that NDP kinase may play a physiological role in signal transduction.     

Mapping the chicken genome: problems and perspectives

Various molecular methods are now used to map the chicken genome, including chromosome scraping, flow cytofluorimetry, zonal centrifugation, construction of chromosome-specific libraries, genetic analysis with polymorphic DNA markers, and in situ hybridization. Two main drawbacks are characteristic of existing maps of chicken chromosomes. First, classic genetic maps (i.e., linkage groups of genes for morphological, physiological, and biochemical characters), physical maps of chromosomes, and new genetic maps constructed on the basis of polymorphic DNA markers (RFLP, RAPD, VNTR, SSR, and CR1-PCR) do not coordinate with one another. Second, a relatively low number of genes is present in classic genetic maps and physical chromosome maps. Application of cytogenetic methods to chromosome mapping in birds is limited because of some specific features characteristic of the organization of avian genomes. For the same reason, studying the location and expression of avian genes is very important. Since mammalian and avian genomes differ in structure, revealing their possible common functional characteristics will provide for a better understanding of the general mechanisms that control biologically important characters in higher animals.     

Intrauterine or oral administration of levonorgestrel in combination with estradiol to perimenopausal women--effects on lipid metabolism during 12 months of treatment

Electrical stimulation of the basal temporal region of the dominant hemisphere before partial temporal lobectomy for epilepsy sometimes produces temporary interruption of language function, but the significance of removal of this area is unknown. We evaluated the correlation between resection of the basal temporal language areas (BTLA) and certain types of postoperative language deficits. In a population of 25 patients, we mapped the inferolateral temporal lobe with cortical electrical stimulation, verifying the positions of the stimulating electrodes with three-dimensional computed tomography (CT). Eighty percent of the patients developed transient language deficits with stimulation, particularly with tests of confrontation naming and comprehension. BTLA was primarily located in the fusiform gyrus, from 1 to 9 cm from the temporal tip. At testing 6-12 months after operation, patients with BTLA resection performed worse (mean 9% decrease) than those with no BTLA resection (mean 4% improvement) on tests of confrontation naming (p = 0.03). Resection size accounted for less of the variance in decrease in confrontation naming than did resection of the BTLA. Tests of performance I.Q. (PIQ), verbal I.Q. (VIQ), or recognition memory for word and verbal learning showed no significant difference between these groups. Most patients do not have language decrease with removal of basal temporal lobe 5-6 cm from the tip, even with removal of BTLA. Some patients, however, have persistent decrease in naming.     

The effects of an outpatient practice guideline at a teaching hospital: a prospective pilot study

BACKGROUND: Platelet-activating factor (PAF) is a bioactive phospholipid which is a potent hypotensive agent. To investigate the role of PAF in renovascular hypertension, we determined the PAF concentration and its production level assessed by the activity of cholinephosphotransferase (CPT) in renal tissue and examined the effect of a PAF antagonist on the mean arterial pressure (MAP) in control and two-kidney with one clipped (2K1C) hypertensive rats. MATERIALS AND METHODS: The concentration of PAF and CPT in the renal medulla and cortex were determined by radioassay. Also, the effect of a PAF antagonist, CV-6209, on MAP was also examined in both 2K1C hypertensive and normal control rats. RESULTS: The PAF concentration and CPT activity were significantly higher in the medulla than in the cortex in both 2K1C hypertensive and normal control rats, and both values in the medulla were also significantly higher in the clipped kidney than in the contralateral unclipped kidney or in control rat kidneys. We also observed a significant negative correlation between the PAF concentration in the medulla, and the medulla weight in the clipped kidney of 2K1C hypertensive rats. Infusion of the PAF antagonist, CV-6209, did not affect MAP in 2K1C hypertensive rats, but was significantly increased (P < 0.05) in control rats. CONCLUSIONS: These findings suggest that PAF, whose production is induced by renal ischemia due to renal artery stenosis, plays an important role in the renomedullary vasodepressor system, but the effect of PAF as a vasodilator in the peripheral vessels is limited in 2K1C hypertension.     

Variants of chromosome 9 in phenotypically normal individuals

The human chromosome 9 displays the highest degree of structural variability. Four different types of variants are described including pericentric inversion, extra G-positive band in the q arm, additional G-positive band in the p arm and duplication of band 9q21-q22. It is important to demonstrate inheritance from a phenotypically normal individual in order to differentiate between a variant chromosome and an abnormal chromosome.     

Retinoid-regulated gene expression in neural development

The discovery and development of information surrounding the retinoic acid receptors (RAR and RXR) has ushered in a new era in understanding the molecular mechanism of action of vitamin A in embryonic development and cellular differentiation. The mechanisms involved in the regulation of gene expression by the retinoids is at least partially known and involves binding of the RAR and RXR to retinoic acid response elements. Additional factors, including coregulatory proteins, associated regulatory elements, and cell-specific factors, may also be involved in determining the specificity of retinoid-regulation of gene expression during development. During embryogenesis, retinoids are required for the development of the posterior hindbrain and its associated structures, as well as for the survival and differentiation of certain classes of neurons and neural crest cell derivatives. At least some of the effects of retinoid on hindbrain development are related to the regulation of Hox gene expression. Additional retinoid-regulated genes have been implicated in nervous system development, and the manner in which they lead to phenotypic changes during embryogenesis remains to be determined.