Huhu grubs (Prionoplus reticularis) are wood-feeding beetle larvae endemic to New Zealand and belonging to the family Cerambycidae. Compared to the wood-feeding lower termites, very little is known about the diversity and activity of microorganisms associated with xylophagous cerambycid larvae. To address this, we used pyrosequencing to evaluate the diversity of metabolically active and inactive bacteria in the huhu larval gut. Our estimate, that the gut harbors at least 1,800 phylotypes, is based on 33,420 sequences amplified from genomic DNA and reverse-transcribed RNA. Analysis of genomic DNA-and RNA-derived data sets revealed that 71% of all phylotypes (representing 95% of all sequences) were metabolically active. Rare phylotypes contributed considerably to the richness of the community and were also largely metabolically active, indicating their participation in digestive processes in the gut. The dominant families in the active community (RNA data set) included Acidobacteriaceae (24.3%), Xanthomonadaceae (16.7%), Acetobacteraceae (15.8%), Burkholderiaceae (8.7%), and Enterobacteriaceae (4.1%). The most abundant phylotype comprised 14% of the active community and affiliated with Dyella ginsengisoli (Gammaproteobacteria), suggesting that a Dyella-related organism is a likely symbiont. This study provides new information on the diversity and activity of gutassociated microorganisms that are essential for the digestion of the nutritionally poor diet consumed by wood-feeding larvae. Many huhu gut phylotypes affiliated with insect symbionts or with bacteria present in acidic environments or associated with fungi.

A diazotroph capable of accumulating significant amounts of polyhydroxyalkanoate was isolated in New Zealand from a bioreactor treating nitrogen-deficient pulp and paper-mill effluent. Strain Y88T is Gram-negative, rod-shaped and positive for catalase, nitrate reductase and urease activities. The complete 16S rRNA gene sequence was most similar to those of other members of the genus Novosphingobium, the highest level of similarity (94.7 %) being found with respect to the type strain of Novosphingobium stygium. We have isolated a bacterial strain from New Zealand pulp and paper-mill effluents (C/N ratio of 140 : 1) undergoing biological treatment in a bioreactor operated under nitrogen-limited conditions. The strain, designated Y88 T , was isolated at 30 u C on nutrient agar (containing, l 21 , 15 g purified agar, 3.0 g beef extract and 5.0 g peptone) with 5 mM NiCl 2 . The cells were Gram-negative, aerobic, non-spore-forming, non-motile rods that formed offwhite/pale yellow colonies within 2-4 days on nutrient agar (lacking NiCl 2 ). The colonies formed were circular, entire, convex and shiny in appearance. The optimum growth temperature for strain Y88T was 30 u C; growth was observed at 25-35 uC but not at 37 uC.Total genomic DNA was extracted as described by Tiirola et al. (2002); total RNA was isolated using an RNAextraction kit according to the instruction of the manufacturer (Qiagen). The 16S rRNA gene was analysed as described by Lane (1991) and the sequence determinedThe GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequence and the nifH gene sequence of strain Y88T are DQ448852 and DQ660368, respectively. A transmission electron micrograph of Y88T cells containing polyhydroxyalkanoate granules is available as a supplementary figure with the online version of this paper.

The temporal stability and change of the dominant phylogenetic groups of the domain bacteria were studied in a model plant-based industrial wastewater treatment system showing high levels of organic carbon removal supported by high levels of N2 fixation. Community profiles were obtained through terminal restriction fragment length polymorphism analysis and cloning of 16S rRNA amplicons followed by sequencing. Bacterial community profiles showed that ten common terminal restriction fragments made up approximately 50% of the measured bacterial community. As much as 42% of the measured bacterial community could be monitored by using quantitative PCR and primers that targeted three dominant operational taxonomic units. Despite changes in wastewater composition and dissolved oxygen levels, the bacterial community composition appeared stable and was dominated by alpha-Proteobacteria and beta-Proteobacteria, with a lesser amount of the highly diverse bacterial phylum Bacteroidetes. A short period of considerable change in the bacterial community composition did not appear to affect treatment performance indicating functional redundancy in this treatment system.

Stolotermes ruficeps is a widespread, primitive, lower termite occupying dead and decaying wood of many tree species in New Zealand's temperate forests. We identified core bacterial taxa involved in gut processes through combined DNA- and RNA (cDNA)-based pyrosequencing analysis of the 16S nucleotide sequence from five S. ruficeps colonies. Most family and many genus-level taxa were common to S. ruficeps colonies despite being sampled from different tree species. Major taxa identified were Spirochaetaceae, Elusimicrobiaceae and Porphyromonadaceae. Others less well known in termite guts were Synergistaceae, Desulfobacteraceae, Rhodocyclaceae, Lachnospiraceae and Ruminococcaceae. Synergistaceae, Lachnospiraceae and Spirochaetaceae were well represented in the RNA data set, indicating a high-protein synthesis potential. Using 130,800 sequences from nine S. ruficeps DNA and RNA data sets, we estimated a high level of bacterial richness (4024 phylotypes at 3% genetic distance). Very few abundant phylotypes were site-specific; almost all (95%) abundant phylotypes, representing 97% of data set sequences, were detected in at least two S. ruficeps colonies. This study of a little-researched phylogenetically basal termite identifies core bacteria taxa. These findings will extend inventories of termite gut microbiota and contribute to the understanding of the specificity of termite gut microbiota.

High levels of nitrogen fixation have been observed in the wastewaters of pulp and paper mills. In this study, we show that nitrogen fixation in a model pulp and paper wastewater treatment system is supported by a high density of nifH sequences that are of low diversity. Quantitative PCR revealed a ratio of nifH to 16S rDNA of 1.14 +/- 0.76 which shows that very high levels of the nifH gene were enriched to support the high rates of nitrogen fixation that occur in this wastewater. Changes in wastewater composition and dissolved oxygen levels did not affect the nifH levels and allowed stable wastewater treatment. The nifH sequences identified display a similar profile to those seen in forest soil environments where nifH sequences derived from alpha-proteobacteria and beta-proteobacteria are also prevalent.