Coconut rhinoceros beetle digestive symbiosis with potential plant cell wall degrading microbes.

Coconut rhinoceros beetle (CRB, Oryctes rhinoceros) is an invasive palm pest whose larvae eat wood, yet lack the necessary digestive enzymes. This study confirmed endogenous CRB cellulase is inactive, suggesting microbial fermentation. The inner lining of the CRB hindgut has tree-like structures covered with a conspicuous biofilm. To identify possible symbionts, 16 S rRNA amplicon sequencing was used on individuals from across Taiwan. Several taxa of Clostridia, an anaerobic class including many cellulolytic bacteria, were highly abundant in most individuals from all locations. Whole metagenome sequencing further confirmed many lignocellulose degrading enzymes are derived from these taxa. Analyses of eggs, larvae, adults, and soil found these cellulolytic microbes are not transmitted vertically or transstadially. The core microbiomes of the larval CRB are likely acquired and enriched from the environment with each molt, and enable efficient digestion of wood.

Using homemade stainless steel dendrometer band for long term tree growth measurements.

Dendrometer bands have been proposed as an accurate method for measuring tree growth. However, the constrained observation window and the material used in them hamper long-term tree growth monitoring. This study devised a dendrometer band made from stainless steel and primarily extended the extension length of the band spring to yield ample space to monitor diameter increments long-term. A total of more than 500 individual trees, including both coniferous and broadleaf trees, were examined. We compared the dendrometer band's long-term performance with diameter tape for 5- and 10-year measurements. The results showed that the measurements of the two methods were highly correlated (R > 0.89) in both measuring periods. Differences between the two measurements for individual trees were typically less than 5 mm, and the mean differences at a stand level were less than 2 mm. These consistent observations suggested that the dendrometer band measurements were reliable for long-term measurement. Using the dendrometer bands, we further demonstrated the annual tree growths of diameter at breast height (DBH) and basal area (BA) for ten years of measurements. The size-dependent relationships between DBH/BA growth and initial DBH were also presented. Owing to their simple installation, low cost, and reliable measurement, these dendrometer bands would be helpful in forestry and forest ecology research.

Correction to: Soil respiration patterns and rates at three Taiwanese forest plantations: dependence on elevation, temperature, precipitation, and litterfall.

Unfortunately, the original article (Huang et al. 2017) contained some errors. The Fig. 4 displayed incorrectly. The correct figure can be found below.

Soil respiration patterns and rates at three Taiwanese forest plantations: dependence on elevation, temperature, precipitation, and litterfall.

BACKGROUND: Soil respiration contributes to a large quantity of carbon emissions in the forest ecosystem. In this study, the soil respiration rates at three Taiwanese forest plantations (two lowland and one mid-elevation) were investigated. We aimed to determine how soil respiration varies between lowland and mid-elevation forest plantations and identify the relative importance of biotic and abiotic factors affecting soil respiration. RESULTS: The results showed that the temporal patterns of soil respiration rates were mainly influenced by soil temperature and soil water content, and a combined soil temperature and soil water content model explained 54-80% of the variation. However, these two factors affected soil respiration differently. Soil temperature positively contributed to soil respiration, but a bidirectional relationship between soil respiration and soil water content was revealed. Higher soil moisture content resulted in higher soil respiration rates at the lowland plantations but led to adverse effects at the mid-elevation plantation. The annual soil respiration rates were estimated as 14.3-20.0 Mg C ha-1 year-1 at the lowland plantations and 7.0-12.2 Mg C ha-1 year-1 at the mid-elevation plantation. When assembled with the findings of previous studies, the annual soil respiration rates increased with the mean annual temperature and litterfall but decreased with elevation and the mean annual precipitation. A conceptual model of the biotic and abiotic factors affecting the spatial and temporal patterns of the soil respiration rate was developed. Three determinant factors were proposed: (i) elevation, (ii) stand characteristics, and (iii) soil temperature and soil moisture. CONCLUSION: The results indicated that changes in temperature and precipitation significantly affect soil respiration. Because of the high variability of soil respiration, more studies and data syntheses are required to accurately predict soil respiration in Taiwanese forests.

Effects of adjacent land-use types on the distribution of soil organic carbon stocks in the montane area of central Taiwan.

BACKGROUND: Soil organic carbon (SOC) stocks can be altered through reforestation and cropping. We estimated the effects of land use on SOC stocks after natural deciduous forests replaced by crops and coniferous plantations by examining the vertical distribution of SOC stocks at different depth intervals in an adjacent Oolong tea (Camellia sinensis L.) plantation, Moso bamboo (Phyllostachys pubescens) forest, Japanese cedar (Cryptomeria japonica) forest, and Taiwania (Taiwania cryptomerioides) forest in central Taiwan. The main soil characteristics, soil nitrogen (N) content, and soil carbon to nitrogen (C/N) ratio were also determined. RESULTS: Different land uses resulted in significantly higher bulk density, lower cation exchange capacity, SOC, soil N, soil C/N ratio, and SOC stocks in croplands compared to forestlands. Due to the long-term application of chemical fertilizers, a significantly lower soil pH was found in the tea plantation. Croplands had a lower soil C/N ratio because of less C input into the soil and a higher mineralization rate of organic carbon during cultivation. Similar SOC stocks were found in Taiwania and Japanese cedar forests (148.5 and 151.8 Mg C ha-1, respectively), while the tea plantation had comparable SOC stocks to the bamboo forest (101.8 and 100.5 Mg C ha-1, respectively). Over 40% of SOC stocks was stored in croplands and over 56% was stored in forestland within the upper 10 cm of soil. CONCLUSIONS: Coniferous plantations can contribute to a higher SOC stock than croplands, and a significant difference can be found in the top 0-5 cm of soil.

Biomass carbon accumulation in aging Japanese cedar plantations in Xitou, central Taiwan.

BACKGROUND: Japanese cedar (Chrytomeria japonica D. Don) is an important plantation species in Taiwan and represents 10% of total plantation area. It was first introduced in 1910 and widely planted in the northern and central mountainous areas of Taiwan. However, a change in forest management from exotic species to native species in 1980 had resulted in few new Japanese cedar plantations being established. Most Japanese cedar plantations are now between 30 and 50 years old and reaching their rotation period. It is of interest to know whether these plantations could be viable for future carbon sequestration through the accumulations of stand carbon stocks. Twelve even-aged Japanese cedar stands along a stand age gradient from 37 to 93 years were selected in Xitou of central Taiwan. The study aims were to investigate the basic stand characteristics and biomass carbon stock in current Japanese cedar stands, and determine the relationships among stand characteristics, tree biomass carbon, and stand age. RESULTS: Our results indicate that existing Japanese cedar plantations are still developing and their live tree biomass carbon continues to accumulate. At stands with a stand age of 90 years, tree density, canopy height, mean diameter at breast height, basal area, and live tree biomass carbon stocks reach to nearly 430 tree ha-1, 27 m, 48 cm, 82 m2 ha-1 and 300 Mg C ha-1, respectively. CONCLUSIONS: Therefore, with no harvesting, current Japanese cedar plantations provide a carbon sink by storing carbon in tree biomass.

Dietary administration of the probiotic, Saccharomyces cerevisiae P13, enhanced the growth, innate immune responses, and disease resistance of the grouper, Epinephelus coioides.

The percent weight gain (PWG) and feeding efficiency (FE) of Epinephelus coioides were calculated. The survival of Saccharomyces cerevisiae P13 in the posterior intestines using a specific primer pair of YMR245w-F/YMR245w-R, non-specific immune parameters of grouper, and its susceptibility to Streptococcus sp. and an iridovirus were determined when the fish were fed diets containing S. cerevisiae at 0 (control), 10(3), 10(5), or 10(7) colony-forming units (cfu) kg(-1) for 4 weeks. Results showed that grouper fed a diet containing S. cerevisiae at the levels of 10(3), 10(5), and 10(7) cfu kg(-1) had significantly increased PGW and FE especially in the 10(7) cfu kg(-1) group which were 211.6% and 1.2, respectively. S. cerevisiae was able to survive in the fish posterior intestines during the S. cerevisiae feeding period. Fish fed a diet containing S. cerevisiae at 10(7) cfu kg(-1) had significantly higher survival rates than those fed the 10(3) cfu kg(-1)S. cerevisiae diet and the control diet after challenge with Streptococcus sp. and an iridovirus, with increased survival rates of 26.6% and 36.6%, respectively, compared to the challenge control group. The phagocytic activity, respiratory burst and superoxide dismutase (SOD) level of head kidney leucocytes as well as serum lysozyme activity and serum alternative complement activity (ACH(50)) of fish fed diets containing S. cerevisiae at 10(5) and 10(7) cfu kg(-1) were significantly higher than those of fish fed the 10(3) cfu kg(-1)S. cerevisiae-contained diet and the control diets after 4 weeks of feeding, and had increased by 20% and 20%, 27.6% and 19.7%, 30.5% and 36.2%, 205.8% and 169.6%, and 90.8% and 80.3%, respectively, compared to the control group. We therefore recommend dietary S. cerevisiae administration of 10(5) and 10(7) cfu kg(-1) to E. coioides to promote growth and enhance immunity and resistance against Streptococcus sp. and an iridovirus especially in the 10(7) cfu kg(-1) group.

Identification and cloning of the alpha2-macroglobulin of giant freshwater prawn Macrobrachium rosenbergii and its expression in relation with the molt stage and bacteria injection.

The full-length complementary (c)DNA of the alpha2-macroglobulin (alpha2M) gene was cloned from haemocytes of the giant freshwater prawn Macrobrachium rosenbergii by reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA end (RACE) methods. The 4875-bp cDNA contains an open reading frame (ORF) of 4419 bp, a 95-bp 5'-untranslated region (UTR), and a 361-bp 3' UTR containing the poly A tail. The ORF encodes a protein of 1472 amino acids (aa) with a 23-residue signal sequence. The molecular mass of the deduced amino acid sequence (1449 aa) was 163.29 kDa with an estimated pI of 4.88. The M. rosenbergii alpha2M sequence contains putative functional domains including a bait region and a GCGEQ internal thiol ester site, and a receptor-binding domain is present as in other aquatic arthropod alpha2Ms. Sequence comparison showed that alpha2M of this prawn had overall respective identities of 38.4%, 45.9%, 45.9%, and 46.0% to those of Scylla serrata, Litopenaeus vannamei, Penaeus monodon, and Marsupenaeus japonicus. A phylogenetic analysis revealed that M. rosenbergii alpha2M is the more-primitive genotype, and it showed significant differentiation from marine crustacean alpha2Ms. alpha2M was mainly expressed in haemocytes. The quantitative real-time RT-PCR analysis showed that alpha2M mRNA transcripts significantly increased in the A stage, achieved the highest level in the C stage, then declined in the D(0/1) stage, and reached the lowest level in the D(2/3) stage in haemocytes of prawn. alpha2M's expression in haemocytes of M. rosenbergii significantly increased at 24 h and 12 h after injection with heat-killed Lactococcus garvieae and Vibrio alginolyticus, respectively, which indicates that alpha2M is involved in the immune response of prawn.

Ageing of black carbon along a temperature gradient.

Black carbon (BC) is regarded as a chemically and biologically stable form of carbon and the changes of BC properties in nature are generally assumed to be minute. However, more and more observations have argued the inertness of BC. The objectives of this study were to characterize the changes of BC properties through ageing processes and to identify if these changes are associated with temperature. Our results showed that ageing of BC occurs over a temperature range from -22 degrees C to 70 degrees C within a short period of 12 months. The main changes of BC properties through ageing were found in elemental composition, surface chemistry, and adsorption properties, where the aged BCs were shown to have higher oxygen concentrations, surface acidity, and negative surface charge but lower C concentrations, pH, surface basicity, point of zero net charge, and also a lower adsorption capacity of hydroquinone, an allelopathic compound, than fresh BC. These ageing processes of BC were affected by temperature and changed over time, with higher temperature and longer incubation time enhancing BC ageing. Our results from a wide temperature range suggest that ageing of BC is likely to occur in any terrestrial regime and that the changes of BC properties through ageing should not be overlooked.