Fluctuation of algal alkaline phosphatase activity and the possible mechanisms of hydrolysis of dissolved organic phosphorus in Lake Barato

For freshwater cyanobacteria, the autofluorescence of phycocyanin is quite high while the in vivo fluorescence (IVF) yield of chlorophyll-a is relatively low, apparently because of low chlorophyll concentrations associated with photosystem II. In eucaryotic phytoplankton, even those with phycobili-protein accessory pigments (e.g. some cryptophytes), the opposite is true. Thus, an IVF ratio which relates phycocyanin to chlorophyll-a signals could be a good index of relative cyanobacterial abundance in the field. Spectrofluorometric scans of whole cells from laboratory cultures indicated that the ratio Em₆₆₀ @ Ex₆₃₀/Em₆₈₀ @ Ex₄₃₀ could be a very sensitive cyanobacterial indicator. Tandem flowthrough fluorometers were then fitted with the appropriate interference filters and their discriminatory power was evaluated with mixtures of cyanobacterial and eucaryotic phytoplankton. Although subject to many of the constraints of other IVF assays, tandem fluorometry should be particularly appropriate for real-time mapping of the relative spatial and temporal distributions of broad phytoplankton taxa in continuous vertical of horizontal profiles in lakes.     

Successful pregnancy in a woman with ovarian failure associated with mutation in the beta-subunit of luteinizing hormone.

BACKGROUND: We report a successful pregnancy in a woman with severe ovarian dysfunction and infertility associated with a variant beta-subunit of luteinizing hormone (LH). METHOD/OUTCOME: A 35-year-old woman consulted our unit for infertility. Laparoscopy and ultrasonography showed obstruction of the right tube and ovulation from the right ovary only. Human menopausal gonadotrophin (hMG) therapy was used for six subsequent cycles, but did not result in conception. Subsequently, marked elevation of follicle-stimulating hormone (FSH) and testosterone, together with polycystic ovary (PCO) were noted. The patient failed to respond to ovarian stimulation by hMG. Severe ovarian dysfunction such as premature ovarian failure (POF) was strongly suspected. Sequence analysis of the LH beta-subunit gene indicated heterozygosity for point mutations Trp(8) to Arg(8) and Ile(15) to Thr(15) in the coding sequence. LH hypersecretion resembling that seen in PCO syndrome was observed. Induction of ovulation by hMG was successful in the first cycle in which the basal LH and FSH were well controlled with gonadotrophin-releasing hormone analog following estrogen-progesterone replacement. She conceived and delivered a healthy male infant at term. CONCLUSION: Clinicians should be clinically aware of patients with immunologically anomalous LH variant who might be at risk of developing ovarian failure within a relatively short time span. Pertinent treatment should be applied without delay in such cases.     

The different effects of recombinant human tumor necrosis factor on rat fibrosarcoma sublines

Summary The antitumor effect of recombinant human tumor necrosis factor (rH-TNF) on two clones of rat fibrosarcoma with different metastatic potential to lymph nodes was examined. The colony formation of clone A, which has high metastatic potential, was completely inhibited by continuous exposure to rH-TNF at 50 U/ml. In contrast, colony formation of clone G, which has low metastatic potential, was not inhibited by high concentrations of rH-TNF (10,000 U/ml). The inhibitory effect of rH-TNF on colony formation by clone A was also observed with a 1-h exposure to rH-TNF. This effect was time and concentration dependent, as determined by the colony assay, ³H-thymidine uptake assay, and ⁵¹Cr-release assay. ³H-thymidine and ³H-uridine uptake per cell of clone A exposed to rH-TNF was not decreased. This suggests that the mechanisms of the antitumor effect of rH-TNF were not due to inhibition of DNA and RNA synthesis of tumor cells. In vivo growth and lymph node metastases of clone A inoculated i.p. to Donryu strain rats were completely suppressed by 14 consecutive i.p. injections of 10⁵ or 10⁶ U/kg per day of rH-TNF. On the other hand the growth of clone G was not influenced by rH-TNF administration.     

Molecular cloning and nucleotide sequencing of oxyR, the positive regulatory gene of a regulon for an adaptive response to oxidative stress in Escherichia coli: homologies between OxyR protein and a family of bacterial activator proteins

Summary Treatment of Escherichia coli and Salmonella typhimurium cells with a low dose of hydrogen peroxide induces expression of a large number of genes, and confers resistance to oxidative stresses. The oxyR gene encodes a positive regulatory protein for a subset of these genes involved in the defense against oxidative damage. We cloned a DNA fragment that contains the E. coli oxyR region on a plasmid vector, and analyzed the nucleotide sequence of the gene. The amino acid sequence of OxyR protein, deduced from the nucleotide sequence, shows a high degree of homology to the sequences of a number of bacterial activator proteins including LysR, cysB, IlvY, MetR and NodD. The product of the oxyR gene identified by the maxicell procedure was a 34 kDa protein, which agrees with the size predicted from the nucleotide sequence of the gene.     

Inhibitory mechanism of acupuncture and moxibustion stimulation on the exteroceptive vibration-induced finger flexion reflex in man

This study indicates that acupuncture and moxibustion stimulation on one side can inhibit Exteroceptive vibration-induced finger flexion reflex (VFR) produced by vibration on the surface of the skin of fingers of both hands. This was thought to be due to that transmission of impulses in the spinal cord producing VFR was inhibited bilaterally, when unilateral acupuncture or moxibustion stimulus was applied. The degree of inhibition with acupuncture and moxibustion stimulation was, in decreasing order, electroacupuncture (insulated needle), electroacupuncture (stainless needle), leaving needle, indirect moxibustion and cold moxibustion in the ipsilateral side, and the order of the leaving needle and the indirect moxibustion was reversed in the contralateral side. By investigating the effects of stimulation of meridian points and their neighboring places, the location of stimulation where VFR was effectively inhibited was found. Furthermore, the role played by the organization metamerism was demonstrated. Also prostaglandin was considered to mediate the effects of acupuncture stimulation on VFR. Concurrent stimulation of the Hég? (LI4) and B?ihuì (GV 20) did not inhibit VFR. In many of the subjects with no manifestation of VFR, VFR occurred when acupuncture stimulus was applied to the B?ihuì.     

Developmental changes in galactosyltransferase activity in the rat small intestine

During postnatal development, UDP-Gal: GlcNAc(beta 1-4)-galactosyltransferase (4 beta-GT) and UDP-Gal:GalNAc(beta 1-3)-galactosyltransferase (3 beta-GT) activities were increased by 17- and 24-fold, respectively, in the rat small intestine. The injection of cortisone into suckling rats resulted in precocious induction of distal 4 beta- and 3 beta-GT activities by 2.7- and 1.8-fold, respectively. Injection of phorbol-12-myristate-13-acetate (PMA) resulted in precocious induction of distal 3 beta-GT by 2.7-fold. These results suggest that intestinal galactosyltransferase activities are under developmental regulation and can be modified by cortisone and PMA.     

Calyculin A and okadaic acid: inhibitors of protein phosphatase activity

Calyculin A and okadaic acid induce contraction in smooth muscle fibers. Okadaic acid is an inhibitor of phosphatase activity and the aims of this study were to determine if calyculin A also inhibits phosphatase and to screen effects of both compounds on various phosphatases. Neither compound inhibited acid or alkaline phosphatases, nor the phosphotyrosine protein phosphatase. Both compounds were potent inhibitors of the catalytic subunit of type-2A phosphatase, with IC50 values of 0.5 to 1 nM. With the catalytic subunit of protein phosphatase type-1, calyculin A was a more effective inhibitor than okadaic acid, IC50 values for calyculin A were about 2 nM and for okadaic acid between 60 and 500 nM. The endogenous phosphatase of smooth muscle myosin B was inhibited by both compounds with IC50 values of 0.3 to 0.7 nM and 15 to 70 nM, for calyculin A and okadaic acid, respectively. The partially purified catalytic subunit from myosin B had IC50 values of 0.7 and 200 nM for calyculin A and okadaic acid, respectively. The pattern of inhibition for the phosphatase in myosin B therefore is similar to that of the type-1 enzyme.     

Breeding ofl-threonine hyper-producer ofEscherichia coli W

Summary l-Threonine hyper-producing mutants were obtained fromEscherichia coli W strain KY-8366, by reducingl-threonine degradation activity and enhancingl-threonine biosynthetic activity. Anl-threonine degradation reaction test using resting cells of KY-8366 suggested that the main pathway ofl-threonine degradation by KY-8366 is via glycine. A strain with reducedl-threonine degradation activity was obtained among those mutants that could not utilizel-threonine as sole nitrogen source. Rifampicin-resistant mutants andl-lysine plus methionine-insentitive mutants were isolated. These mutants showed enhanced aspartokinase levels and accumulated morel-threonine than the parental strains. Mutant H-4290 accumulated 58 g/l ofl-threonine.     

Effects of auxin and gibberellin on conidial germination and elongation of young hyphae in a cyclic 3′:5′ adenosine monophosphate-dependent protein kinase mutant of Neurospora crassa

The possibility that plant growth regulators may relate to a cyclic 3:5 adenosine monophosphate (cAMP)-dependent protein kinase through the control of cAMP level in the conidial germination process of Neurospora crassa was examined using a cAPM-dependent protein kinase mutant (cpk mutant) which is thought to be cAMP-independent because of defect in the regulatory subunit of cAMP-dependent protein kinase. IAA, 2,4-D and GA₃ promoted conidial germination and elongation of young hyphae in the mutant as well as in the wild-type. The result suggests that the effects of auxin and gibberellin on germination and hyphal elongation are not mediated by cAMP.