Nature-based tourism (NBT), alternatively known as ecotourism, is a rapidly expanding area in the tourism travel sector. States such as Louisiana with a well established urban-based tourism industry may have expansion opportunities through development of complementary nature-based tourism. This study analyzes the decision to participate in nature-based tourism and identifies factors, including attitudinal, that influence the decision to participate in NBT among Louisiana tourists.

Background: Increasing evidence suggests that neprilysin (NEP) may be the major degrading enzyme of amyloid beta (Aβ) in the brain and the NEP gene has been proposed as a candidate gene for Alzheimer's disease (AD). Association results between the NEP gene and AD are still preliminary. This study investigates the effect of the polymorphisms of −204G/C and 159C/T in the NEP gene on the development of sporadic Alzheimer's disease (SAD) in a southern Chinese community.

Method: 236 sporadic late-onset AD patients were recruited from Guangzhou Psychiatric Hospital in southern China, and 332 healthy elderly controls were enrolled from three old age homes in suburban Guangzhou. NEP and ApoE genotype were determined by PCR–RFLP.

Results: No differences in genotypic and allelic frequencies of −204G/C and 159C/T polymorphisms in NEP were found between AD and control group (for −204G/C genotype: χ2 = 2.34, P > 0.05; for allele: χ2 = 2.31, P > 0.05; for 159C/T genotype: χ2 = 1.34, P > 0.05; for allele: χ2 = 0.88, P > 0.05). Neither was any difference found in genotypic and allelic frequency when stratified by sex or by ApoE ε4 allele (P > 0.05).

Conclusions: Our results suggest that −204G/C and 159C/T polymorphisms of the NEP gene may not be associated with SAD. Moreover, both sex and ApoE ε4 allele do not affect the distribution of NEP gene polymorphisms.

The plastid organelle of plants, eukaryotic algae and apicomplexan protists contains its own DNA genome (the ‘plastome’). In higher plants, at least two RNA polymerases have been shown to participate in the transcription of plastid genes. The multisubunit ‘plastid-encoded plastid RNA polymerase’ (PEP) is derived from the cyanobacterial ancestor of the organelle and is structurally similar to eubacterial RNA polymerases. The core subunits of PEP are encoded by genes on the plastome, whilst sigma-like transcription factors and other regulatory factors are encoded in the nucleus. In contrast, the ‘nuclear-encoded plastid RNA polymerase’ (NEP) is a single-subunit enzyme related to the T3/T7 bacteriophage and mitochondrial RNA polymerases that is believed to have arisen by duplication of the nuclear gene for the mitochondrial enzyme. The situation in algal plastids is less well understood. All algal groups, apart from possibly the dinoflagellates, possess a PEP but it is far from clear whether any possess additional plastid RNA polymerases. In this article we review what is known about the transcription apparatus of algal plastids, and examine the evidence for and against the presence of NEPs.