Application of Paper Chromatograms to the Study of Inducers of λ Bacteriophage in Escherichia coli

A procedure has been developed whereby paper chromatograms of agents which induce λ bacteriophage in Escherichia coli can be developed using bioautographs with a lysogenic test system. Well-defined plaque-forming zones are produced indicating the area on the paper chromatogram where the active inducing material can be located. A mixture of the bacteriophage-inducing antibiotic, mitomycin C, and the noninducing antibiotic, paromomycin, was resolved into its components on paper strips with an ethyl acetate-methanol solvent system. The location of both antibiotics could thus be readily observed. Antibacterial and inducing activities were found to be identical with a crude fermentation solid, NSC-B-158,791. The use of this procedure for resolution of multicomponent inducing activities in antibiotic beers and for characterization of active components which may be potential antitumor antibiotics is indicated.     

The bifunctional role of LiuE from <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis>, displays additionally HIHG-CoA lyase enzymatic activity

Pseudomonas aeruginosa is able to utilize leucine/isovalerate and acyclic terpenes as sole carbon sources. Key enzymes which play an important role in these catabolic pathways are 3-hydroxy-3-methylglutaryl-coenzyme A (CoA) lyase (EC 4.1.3.4; HMG-CoA lyase) and the 3-hydroxy-3-isohexenylglutaryl-CoA lyase (EC 4.1.2.26; HIHG-CoA lyase), respectively. HMG-CoA lyase is encoded by the liuE gene while the gene for HIHG-CoA lyase remains unidentified. A mutant in the liuE gene was unable to utilize both leucine/isovalerate and acyclic terpenes indicates an involvement of liuE in both catabolic pathways (Chávez-Avilés et al. 2009, FEMS Microbiol Lett 296:117–123). The LiuE protein was purified as a His-tagged recombinant protein and in addition to show HMG-CoA lyase activity (Chávez-Avilés et al. 2009, FEMS Microbiol Lett 296:117–123), also displays HIHG-CoA lyase activity, indicating a bifunctional role in both the leucine/isovalerate and acyclic terpenes catabolic pathways.     

Fern and lycopod spores rain in a cloud forest of Hidalgo,Mexico

The aim of this study was to determine the composition of the “spore rain” of ferns and lycopods in a cloud forest. We tested whether the canopy impedes spore dispersal to surrounding areas and how spore dispersal is affected by rainfall. The spores were captured with a modified Bush–Gosling trap placed at 30 cm above ground level in forested and non-forested sites from March 2009 to February 2010. We collected 2462 fern spores from 158 morphospecies of which 76 were identified to species level. Thirty-seven species were found exclusively in the spore rain, and 39 were found as sporophytes as well (local component). Mean daily spore density (spores m^?2) was calculated to find the sporulation period for each species. Twenty species showed seasonal patterns of sporulation. The highest spore density was found at the forested site (70 morphospecies and 1856 spores), of which 39 morphospecies (1482 spores) corresponded to the local vegetation. Fifty-five taxa were shared between the forested and non-forested site. In the non-forested site, 605 spores were captured belonging to 64 species. The density of spore rain between sites was significantly different. The rainfall amount was the same at both sites, with a dry period in March, April, and July 2009, and February 2010. There was a negative effect of rainfall on spore rain. The main sporulation occurred in the dry season with strong winds. Although the canopy inhibits airborne dispersal of fern spores, a small amount of spores can disperse beyond the canopy and reach surrounding areas. The rainfall might wash spores to ground and favor the colonization and the establishment of new populations.     

Influence of spermine and nitrogen deficiency on growth and secondary metabolites accumulation in Castilleja tenuiflora Benth. cultured in a RITA® temporary immersion system

The effect of exogenous spermine (SPM) on Castilleja tenuiflora shoots developing under nitrogen deficiency (ND) stress was evaluated. Shoots cultivated in a temporary immersion system were subjected to four experimental treatments: (1) control; (2) exogenous SPM; (3) ND; and (4) ND+SPM. Shoots were longer in the ND+SPM treatment (6.3 ± 0.5 cm) than in the ND treatment (4.2 ± 0.5 cm). The total chlorophyll content was similar in the control and SPM treatments (0.41 µg mg^?1 FM) and the highest values of total phenolic content were detected at 21 days in the ND+SPM treatment (84.1 ± 0.05 GAE g^?1 DM). In the ND+SPM treatment, the phenylalanine ammonia lyase activity increased earlier than in ND treatment, and reached its maximum at day 21 (3.9 ± 0.2 µmol E‐CIN h^?1 mg^?1 protein). Compared with the control, the ND and ND+SPM treatments resulted in increased secondary metabolites contents in both root and aerial parts. The strongest effect was in the roots, where the SPM and ND+SPM treatments both resulted in increased quercetin content (4.3‐fold that in the control). Our results showed that SPM partially counteract the damage caused by ND and results in increased contents of valuable bioactive compounds.     

Colorimetric Paper-based Detection of Escherichia coli,Salmonella spp., and Listeria monocytogenes from Large Volumes of Agricultural Water

This protocol describes rapid colorimetric detection of Escherichia coli, Salmonella spp., and Listeria monocytogenes from large volumes (10 L) of agricultural waters. Here, water is filtered through sterile Modified Moore Swabs (MMS), which consist of a simple gauze filter enclosed in a plastic cartridge, to concentrate bacteria. Following filtration, non-selective or selective enrichments for the target bacteria are performed in the MMS. For colorimetric detection of the target bacteria, the enrichments are then assayed using paper-based analytical devices (µPADs) embedded with bacteria-indicative substrates. Each substrate reacts with target-indicative bacterial enzymes, generating colored products that can be detected visually (qualitative detection) on the µPAD. Alternatively, digital images of the reacted µPADs can be generated with common scanning or photographic devices and analyzed using ImageJ software, allowing for more objective and standardized interpretation of results. Although the biochemical screening procedures are designed to identify the aforementioned bacterial pathogens, in some cases enzymes produced by background microbiota or the degradation of the colorimetric substrates may produce a false positive. Therefore, confirmation using a more discriminatory diagnostic is needed. Nonetheless, this bacterial concentration and detection platform is inexpensive, sensitive (0.1 CFU/ml detection limit), easy to perform, and rapid (concentration, enrichment, and detection are performed within approximately 24 hr), justifying its use as an initial screening method for the microbiological quality of agricultural water.     

Expression of bik cluster and production of bikaverin by Fusarium oxysporum f. sp. lycopersici grown using two alternate nitrogen sources

International Microbiology - The genus Fusarium can be utilized to produce a great variety of secondary metabolites under specific culture conditions, including pigments of increasing...     

Identification of four distinct ‘Candidatus Phytoplasma’ species in pomegranate trees showing witches' broom,little leaf and yellowing in Jordan,and preliminary insights on their putative insect vectors and reservoir plants

During field surveys conducted in northern Jordan from June to November 2020, phytoplasma-like symptoms, including leaf yellowing/reddening and rolling, little leaf and witches' broom were observed in pomegranate. Disease incidence in 22 surveyed orchards ranged from 30% to 65%. Nested PCR-based amplification of 16S rRNA gene detected phytoplasmas in 17% of collected symptomatic pomegranate trees. Amplicon nucleotide sequence analyses allowed attributing the detected phytoplasmas to ‘Candidatus Phytoplasma solani’, ‘Ca. P. aurantifolia’, ‘Ca. P. asteris’ and ‘Ca. P. ulmi’. These phytoplasmas were found in plants showing specific symptoms and differentially distributed in the considered locations. Additionally, three cicadellids (Macrosteles sexnotatus, Cicadulina bipunctata and Psammotettix striatus) and two non-crop plants (Plantago major and Capsicum annuum) resulted hosting ‘Ca. P. asteris’ strains, and one cicadellid (Balclutha incisa) was carrying a ‘Ca. P. solani’ strain. A new pomegranate disease complex associated with multiple phytoplasmas, including ‘Ca. P. aurantifolia’ and ‘Ca. P. ulmi’, never reported before in this host plant, is described here. Moreover, preliminary indications are provided on its possible epidemiology in Jordan, involving two putative insect vectors (M. sexnotatus, B. incisa) first reported in the Country.     

The in vitro reconstitution of rough endoplasmic reticulum membrane derived from human placenta

The isolation of rough endoplasmic reticulum from human placenta is described. Puromycin facilitated the detachment of the majority of the ribosomes from the membrane. Ribosomes could be re-attached to the stripped membrane, and puromycin was also necessary for detaching the rebound ribosomes, indicating that peptidyl-tRNA anchors the ribosomes to the membrane in both the native and the reconstituted rough membrane. Peptides labeled in-vitro on membrane bound ribosomes (native and reconstituted rough membrane) remained associated with the membrane after the ribosomes were detached. A protein with an electrophoretic mobility in SDS gels identical to that of HPL is among the membrane associated nascent proteins of the native and the reconstituted rough membrane.