RECENT APPEARANCE OF CYLINDROSPEMOPSIS (CYANOBACTEIUA) IN FIVE HYPEREUTROPHIC FLORIDA LAKES1

Observations of historical and recent phytoplankton samples from five hypereutrophic Florida lakes indicate that nitrogen-fixing cyanobacteria in the genus Cylindrospermopsis Seenayya et Subba Raju have entered these water-bodies sometime in the last 30 years. Cylindrospermopsis forms a year-round bloom in one of the five lakes, dominates seasonally in another, and is at least at times an important component of the phytoplankton community in the remaining three. The increase in abundance of Cylindrospermopsis in Florida lakes could have implications for water management.     

Structural studies on glycolipids. Part 1: 220 MHz pmr spectra of acetylated galactocerebrosides

The pmr spectra of fully acetylated 2S: 3R-2 amino-trans-4 octadecene-1, 3 diol (sphingosine) (lb), 2S : 3R-2 aminooctadecane-1, 3 diol (dihydrosphingosine) (2b), 1-O-β-D-galactopyranosyl-2S : 3R-2 tetracosanoylamido-trans-4 octadecene-1, 3 diol (cerasine) (3b), and 1-O-β-D-galactopyranosyl-2S : 3R-2 (2′ hydroxy) tetracosanoylamido-trans-4 octadecene-1, 3 diol (phrenosine) (4b), were determined in chloroform-d, acetone-d₆, and benzene-d₆ at 220 MHz. The relative chemical shifts of the various protons in the three solvents were different enough as to permit configurational and conformational information to be derived by partial first order analysis.     

Activation by reduction of the resting form of cytochrome c oxidase: tests of different models and evidence for the involvement of CuB

(1) The reaction of the resting form of oxidised cytochrome c oxidase from ox heart with dithionite has been studied in the presence and absence of cyanide. In both cases, cytochrome a reduction in 0.1 M phosphate (pH 7) occurs at a rate of 8.2.10(4) M-1.s-1. In the absence of cyanide, ferrocytochrome a3 appears at a rate (kobs) of 0.016 s-1. Ferricytochrome a3 maintains its 418 nm Soret maximum until reduced. The rate of a3 reduction is independent of dithionite concentration over a range 0.9 mM-131 mM. In the presence or cyanide, visible and EPR spectral changes indicate the formation of a ferric a3/cyanide complex occurs at the same rate as a3 reduction in the absence of cyanide. A g = 3.6 signal appears at the same time as the decay of a g = 6 signal. No EPR signals which could be attributed to copper in any significant amounts could be detected after dithionite addition, either in the presence or absence of cyanide. (2) Addition of dithionite to cytochrome oxidase at various times following induction of turnover with ascorbate/TMPD, results in a biphasic reduction of cytochrome a3 with an increasing proportion of the fast phase of reduction occurring after longer turnover times. At the same time, the predominant steady state species of ferri-cytochrome a3 shifts from high to low spin and the steady-state level of reduction of cytochrome a drops indicating a shift in population of the enzyme molecules to a species with fast turnover. In the final activated form, oxygen is not required for fast internal electron transfer to cytochrome a3. In addition, oxygen does not induce further electron uptake in samples of resting cytochrome oxidase reduced under anaerobic conditions in the presence of cyanide. Both findings are contrary to predictions of certain O-loop types of mechanism for proton translocation. (3) A measurement of electron entry into the resting form of cytochrome oxidase in the presence of cyanide, using TMPD or cytochrome c under anaerobic conditions, shows that three electrons per oxidase enter below a redox potential of around +200 mV. An initial fast entry of two electrons is followed by a slow (kobs approximately 0.02 s) entry of a third electron.(ABSTRACT TRUNCATED AT 400 WORDS)     

Hypophysectomy and hemivasectomy can inhibit the testicular hemicastration response of the mature rat

Three questions were asked in an attempt to understand how testosterone (T) concentration in the veins of the remaining testis can double within 24 h after hemicastration in the mature rat without a change in plasma luteinizing hormone (LH) levels. These three questions (and their answers) were: 1) Can the testicular hemicastration response occur in hypophysectomized rats? Answer, No. 2) Does LH binding to the testis increase after hemicastration? Answer, No. 3) Is there a neural route to the testis alternate to the superior spermatic plexi? Answer, Yes, apparently there is, since hemivasectomy contralateral to the excised testis partially suppressed the testicular hemicastration response (150.4 +/- 13.2 ng/ml in hemicastrated, sham- hemivasectomized rats [n = 18] vs. 109.4 +/- 11.6 ng/ml in hemicastrated, hemivasectomized rats [n = 18], P less than 0.026). It was concluded that LH was probably necessary to the testicular hemicastration response but that its presence did not provide a mechanism. The response was mediated at least partly through the inferior spermatic nerves associated with the vas deferens. A possible reason, although highly speculative, for failure to previously block the testicular hemicastration response by bilateral denervation of the superior spermatic plexi (Mock and Frankel , 1982) was that during the 12-wk interval between denervation and hemicastration, testicular innervation functionally transferred from the superior spermatic to the inferior spermatic nerves.     

Remission of diarrhoea due to cryptosporidiosis in an immunodeficient child treated with hyperimmune bovine colostrum.

A boy aged 6 months who presented with poor weight gain, diarrhoea, and infection with Pneumocystis carinii was found to have congenital hypogammaglobulinaemia, which did not improve despite monthly treatment with intravenous gammaglobulin. At the age of 3 years and 2 months he developed severe vomiting and diarrhoea due to cryptosporidiosis, which failed to respond to conventional treatment. Infusion of hyperimmune bovine colostrum produced against parasite antigen, given by nasogastric tube, was started after symptoms had persisted for three weeks. His vomiting and diarrhoea resolved within five days of treatment, and oocysts were no longer seen in the stools after eight days. Later, however, he developed a rare complication, and oocysts were found in the common bile duct. Hyperimmune bovine colostrum may be useful in the treatment of many patients with immunodeficiency disorders.