Studies on degradation efficiency of polycaprolactone by a naturally-occurring bacterium.

We report a strain of Bacillus, isolated from the rhizosphere of the mangrove Sesuvium portulacastrum, that degrades polycaprolactone (PCL) on timescales that are a factor of three shorter than hitherto reported, with complete degradation in only 20 days. The bacterium has been identified as Bacillus pumilus by means of 16S rRNA gene sequencing and FAME analysis; it secretes proteases and lipases and its ‘de-polymerase’ activity is evident by the zone of clearing in emulsified PCL. It is an aerobic chemoheterotroph capable of utilizing a variety of carbohydrates. Although not a true psychrophile, is a mesophile, growing optimally over a temperature range 30-45° C and pH range 5-12.5. It is a halophile tolerating NaCl concentrations up to 10% w/v, and is unique in degrading and utilizing PCL and its monomer, e-caprolactone (CL), as a sole carbon source. Degradation of PCL was monitored using Fourier Transform Infrared (FTIR) spectroscopy, light microscopy and scanning electron microscopy (SEM). This degradation was found to be enhanced by salts (NaCl, KCl, MgSO4, Na2HPO4) and at medium pH values in excess of 7. Under the same growth conditions, another standard Bacillus pumilus strain showed somewhat reduced PCL-degradation.

A homologue of the defender against the apoptotic death gene (dad1 )in UV-exposed Chlamydomonas cells is downregulated with the onset of programmed cell death.

We report here the isolation of a homologue of the potential anti-apoptotic gene, defender against apoptotic death (dad1 )from Chlamydomonas reinhardtii cells.Using polymerase chain reaction (PCR),we investigated its expression in the execution process of programmed cell death (PCD)in UV-C exposed dying C.reinhardtii cells.Reverse- transcriptase (RT)-PCR showed that C.reinhardtii dad1 amplification was drastically reduced in UV-C exposed dying C.reinhardtii cells.We connect the downregulation of dad1 with the upregulation of apoptosis protease activating factor-1 (APAF-1)and the physiological changes that occur in C.reinhardtii cells upon exposure to 12 J/m 2 UV-C in order to show a reciprocal relationship between proapoptotic and inhibitor of apoptosis factors.The temporal changes indicate a correlation between the onset of cell death and dad1 downregulation.The sequence of the PCR product of the cDNA encoding the dad1 homologue was aligned with the annotated dad1 (C_20215)from the Chlamydomonas database (http://genome.jgi-psf.org:8080/annotator/servlet/jgi.annotation.Annotation?pDb=chlre2); Annotation?pDb=chlre2 );this sequence was found to show 100% identity,both at the nucleotide and amino acid level. The 327 bp transcript showed an open reading frame of 87 amino acid residues.The deduced amino acid sequence of the putative C.reinhardtii DAD1 homologue showed 54% identity with Oryza sativa, 56 identity with Drosophila melanogaster, 66% identity with Xenopus laevis, and 64% identity with Homo sapiens,Sus scrofa,Gallus gallus,Rattus norvegicus and Mus musculus.

Purification and characterization of a Ca(2+)-dependent/calmodulin-stimulated protein kinase from moss chloronema cells.

We have demonstrated the presence of a Ca2+-dependent/calmodulin-stimulated protein kinase (PK) in chloronema cells of the moss Funaria hygrometrica. The kinase, with a molecular mass of 70,000 daltons (PK70), was purified to homogeneity using ammonium sulphate fractionation, DEAE-cellulose chromatography, and calmodulin (CaM)-agarose affinity chromatography. The kinase activity was stimulated at a concentration of 50 mM free Ca2+, and was further enhanced 3-5-fold with exogenously added 3-1000 nm moss calmodulin (CaM). Autophosphorylation was also stimulated with Ca2+ and CaM. Under in vitro conditions, PK70 phosphorylated preferentially lysine-rich substrates such as HIIIS and HVS. This PK shares epitopes with the maize Ca2+-dependent/calmodulin-stimulated PK (CCaMK) and also exhibits biochemical properties similar to the maize, lily, and tobacco CCaMK. We have characterized it as a moss CCaMK.