Soil and bark biodiversity forms discrete islands between vineyards that are not affected by distance or management regime

Within geographic regions, the existing data suggest that physical habitat (bark, soil, etc.) is the strongest factor determining agroecosystem microbial community assemblage, followed by geographic location (site), and then management regime (organic, conventional, etc.). The data also suggest community similarities decay with increasing geographic distance. However, integrated hypotheses for these observations have not been developed. We formalized and tested such hypotheses by sequencing 3.8 million bacterial 16S, fungal ITS2 and non-fungal eukaryotic COI barcodes deriving from 108 samples across two habitats (soil and bark) from six vineyards sites under conventional or conservation management. We found both habitat and site significantly affected community assemblage, with habitat the stronger for bacteria only, but there was no effect of management. There was no evidence for community similarity distance–decay within sites within each habitat. While communities significantly differed between vineyard sites, there was no evidence for between site community similarity distance–decay apart from bark bacterial communities, and no correlations with soil and bark pH apart from soil bacterial communities. Thus, within habitats, vineyard sites represent discrete biodiversity islands, and while bacterial, fungal and non-fungal eukaryotic biodiversity mostly differs between sites, the distance by which they are separated does not define how different they are.     

Deletion of the trichodiene synthase gene of Fusarium venenatum: two systems for repeated gene deletions.

The trichodiene synthase (tri5) gene of Fusarium venenatum was cloned from a genomic library. Vectors were created in which the tri5 coding sequence was replaced with the Neurospora crassa nitrate reductase (nit3) gene and with the Aspergillus nidulans acetamidase (amdS) gene flanked by direct repeats. The first vector was utilized to transform a nitrate reductase (niaD) mutant of F. venenatum to prototrophy, and the second vector was utilized to confer acetamide utilization to the wild-type strain. Several of the transformants lost the capacity to produce the trichothecene diacetoxyscirpenol and were shown by hybridization analysis to have gene replacements at the tri5 locus. The nit3 gene was removed by retransformation with a tri5 deletion fragment and selection on chlorate. The amdS gene was shown to excise spontaneously via the flanking direct repeats when spores were plated onto fluoroacetamide.     

Absence of 6-Hydroxydopamine in the Rat Brain After Treatment with Stimulants and Other Dopaminergic Agents: A Mass Fragmentographic Study

Abstract: Formation of 6-hydroxydopamine (6-OHDA) from dopamine has been hypothesized to mediate neuro-degeneration induced by some psychostimulants. Although the emergence of a 6-OHDA-like substance was reported in the striatum of methamphetamine-treated rats, this substance has not been identified by a direct approach. We used mass fragmentography to search for 6-OHDA in the rat frontal cortex and striatum after the administration of a number of drugs including 3,4-dihy-droxyphenyl-L-alanine, methamphetamine, amphetamine, and cocaine, all of which increase synaptic dopamine. No 6-OHDA was detected after the acute systemic administration of these agents. Intraventricular administration of 6-OHDA (10 μg/rat.) produced measurable concentrations of 6-OHDA that were higher in the striatum than in the frontal cortex. Intraventricular administration of 2,4,5-trihydroxy-phenyl-D,L-alanine (6-OHDOPA; 10 μg/rat) produced similar concentrations of 6-OHDA in both regions. Pargyline, but not carbidopa (α-methyldopahydrazine), enhanced the effect of intraperitoneal 6-OHDOPA administration (80 mg/kg). We conclude that (1) 6-OHDOPA can cross the blood-brain barrier and is converted to 6-OHDA in the brain, (2) 6-OHDA is a substrate for monoamine oxidase(s) and therefore a search for its purported deaminated metabolite is warranted, and (3) acute treatment with the above stimulants either does not lead to the formation of 6-OHDA or produces concentrations below the detection limit of the assay (<34 pg/mg of protein).