Phosphate stress triggers the conversion of glycerol into l-carnitine in Pseudomonas fluorescens.

Glycerol, a by-product of the biofuel industry is transformed into l-carnitine when the soil microbe Pseudomonas fluorescens is cultured in a phosphate-limited mineral medium (LP). Although the biomass yield was similar to that recorded in phosphate-sufficient cultures (HP), the rate of growth was slower. Phosphate was completely consumed in the LP cultures while in the HP media, approximately 35 % of the initial phosphate was detected at stationary phase of growth. The enhanced production of α-ketoglutarate (KG) in HP cultures supplemented with manganese was recently reported (Alhasawi et al., 2017). l-carnitine appeared to be a prominent metabolite in the spent fluid while the soluble cellular-free extract was characterized with peaks attributable to lysine, γ-butyrobetaine (GB), acetate and succinate in the LP cultures. Upon incubation with glycerol and NH4Cl, the resting cells readily secreted l-carnitine and revealed the presence of such precursors like GB, lysine and methionine involved in the synthesis of this trimethylated moiety. Functional proteomic studies of select enzymes participating in tricarboxylic acid cycle (TCA), oxidative phosphorylation (OP), glyoxylate cycle and l-carnitine synthesis revealed a major metabolic reconfiguration evoked by phosphate stress. While isocitrate dehydrogenase-NAD+ dependent (ICDH-NAD+) and Complex I were markedly diminished, the activities of γ-butyrobetaine aldehyde dehydrogenase (GBADH) and l-carnitine dehydrogenase (CDH) were enhanced. Real-time quantitative polymerase chain reaction (RT-qPCR) analyses pointed to an increase in transcripts of the enzymes γ-butyrobetaine dioxygenase (bbox1), S-adenosylmethionine synthase (metK) and l-carnitine dehydrogenase (lcdH). The l-carnitine/γ-butyrobetaine antiporter (caiT) was enhanced more than 400-fold in the LP cultures compared to the HP controls. This metabolic reprogramming modulated by phosphate deprivation may provide an effective technology to transform glycerol, an industrial waste into valuable l-carnitine.

New Cockroaches (Dictyoptera: Blattodea) from French Guiana and a Revised Checklist for the Region.

Although French Guiana is one of the greatest hotspots of cockroach biodiversity on Earth, there are still undocumented species. From both newly collected and museum specimens, we provide species descriptions for Buboblatta vlasaki sp. nov., Lamproblatta antoni sp. nov., and Euhypnorna bifuscina sp. nov. and report new geographic records for species in the genera Epilampra Burmeister, Euphyllodromia Shelford, Ischnoptera Burmeister, and Euhypnorna Hebard. Finally, we update the checklist of species known from the region to 163 total species records from French Guiana, making it the second greatest hotspot of known cockroach biodiversity on Earth.

A complete kinetic study of GG versus AG plantination suggests that the doubly aquated derivatives of cisplatin are the actual DNA binding species.

The hairpin-stabilized double-stranded oligonucleotides d(TATGGTATT4ATACCATA) (I) and d(TATAGTATT4ATACTATA) (II) were allowed to react with the three aquated forms of the antitumor drug cisplatin (cis-[PtCl2(NH3)2], 1) which are likely candidates for DNA binding, that is, cis-[PtC1(NH3)2(H2O)]+ (2), cis-[Pt(NH3)2(H2O)2]2+ (3), and its conjugate base cis-[Pt(OH)(NH3)2(H2O)]+ (4). The reaction between I and [Pt(NH3)3(H2O)]2+ (5) was also studied for comparison. All reactions were monitored by HPLC. The platination reactions of I and II were carried out in NaClO4 (0.1M) at 293 K and at a constant pH of 4.5 +/- 0.1 for 2, 3, and 5. The data relative to the platination by 4 were obtained from measurements in unbuffered NaClO4 solutions (0.1M) at a starting pH close to neutrality, where 3 and 4 are present in equilibrium. In this case, a fit function describing the pH-time curve allowed the determination of the actual concentrations of 3, 4, and the dihydroxo complex. The platination rate constants characterizing the bimolecular reactions between either I or II and 2, 3, and 4 were individually determined along with the rate constants for hydrolysis of the chloro-monoadducts and for the chelation reactions of the aqua-monoadducts. The reactivity of compounds 2-5, which have the general formula cis-[Pt(NH3)2(H2O)(Y)]2+/-, decreases in the order 3>4>5>>2, that is, Y= H2O > OH- >NH3 >> Cl-, which is the order of decreasing hydrogen-bond donating ability of Y. Deprotonation of 3 to 4 reduces the reactivity of the platinum complex only by a factor of approximately equals 2, and both complexes discriminate between the different purines of I and II in the same manner. Whereas 3 and 4 react approximately three times faster with the GG sequence of I than with the AG sequence of II, 2 shows a similar reactivity towards both sequences. In view of the well-established preferential binding of cisplatin to GG sequences of DNA in vivo and in vitro, this result suggests that the actual DNA platination species are derived from double hydrolysis of cisplatin.

A single d(GpG) cisplatin adduct on the estrogen response element decreases the binding of the estrogen receptor.

Both cisplatin and the estrogen receptor (ER) are known to bend DNA. The influence of the bending of sequences by the d(GpG)cisPt adduct binding of ER to estrogen response element (ERE)-like sequences was examined. Three ERE-like oligonucleotides with different affinities for ER and which include a GG in the linker sequence were designed in order to form a single central d(GpG)cisPt adduct. Using electrophoretic mobility shift assay and Scatchard analysis, it was shown that the presence of a single d(GpG)cisPt adduct in the linker sequence decreases the ER affinity for DNA. These results do not support a critical role of a DNA bend in the initial recognition of ERE by ER. Then, the platination of DNA outside of the ERE half-sites decreases the interaction of ER with ERE.

CL307-24, a new antibiotic complex from Saccharopolyspora aurantiaca sp. nov. II. Physico-chemical and biological properties.

CL307-24I, the main component of the CL307-24 complex produced by Saccharopolyspora aurantiaca sp. nov., was found to be a potent inhibitor of yeast mitochondrial ATPase. CL307-24I displayed a high degree of activity towards some coryneform bacteria and also has been shown to possess an insecticidal activity. Its biological and physico-chemical properties clearly distinguish it from previously known ATPase inhibitors.

Analysis of amphoteric surfactants of the alkylaminopropylglycine type by gas chromatography.

A procedure was developed for gas chromatographic analysis of glycine-type amphoteric surfactants. The commercial samples contained N-alkylaminopropylglycines, N-alkylamines and N-alkylaminopropylamines. Some di- and triacids were also detected. The method proposed allows a good separation according to both the carbon number and the chemical function.