Isolation of an aerobic denitrifying bacterial strain NS-2 from the activated sludge of piggery wastewater treatment systems in Taiwan possessing denitrification under 92% oxygen atmosphere

AIMS: To isolate aerobic denitrifying bacteria which will be applied to piggery wastewater treatment facilities for enhanced nitrate and nitrite removal. METHODS AND RESULTS: Nitrate-supplemented basal medium in airtight, crimp-sealed serum bottles containing an atmosphere of 92% oxygen was inoculated with denitrifiers, strains NS-2 and SM-3, and incubated at 30 degrees C. After 20 h, the concentration of nitrate was decreased rapidly by both NS-2 and SM-3. Nitrite production was almost zero during the whole experimental period for both strains. Nitrogen gas production peaked at the 20 h for both NS-2 (8.20 +/- 1.03 mmol l(-1)) and SM-3 (3.93 +/- 0.16 mmol l(-1)). CONCLUSIONS: Strain NS-2, which produced the highest N2 concentration in this work, was identified as Pseudomonas stutzeri. This strain is the most capable of aerobic and anaerobic conversion of nitrate to N2 without forming a nitrite intermediate. SIGNIFICANCE AND IMPACT OF THE STUDY: Strain NS-2 is highly promising for future application in in situ piggery wastewater treatment.     

Impacts of caterpillar disturbance on forest net primary production estimation in China

The study described the uncertainties of NPP estimation due to larch defoliation by caterpillars during 2001–2004 in Northeastern China, which is an order of magnitude larger in area and severe than all previous recorded outbreaks. Using “representative needles” collected in the field, we related spectral responses and photosynthetic contents of needles to ecophysiological parameters in NPP estimation for different degrees of caterpillar damage. It is concluded that locations of reflection peaks at or near green red near-infrared wavelength moving toward long-wave direction with aggravated damage degree, which is useful to earlier prediction of caterpillar damage. Contents of chlorophyll-a reduced by 40.26, 66.29 and 86.88% for light, moderate and severe damage samples respectively compared with healthy, chlorophyll-b reduced by 20.79, 52.67 and 82.39%, and carotenoid reduced by 9.80, 45.06 and 73.15%. Estimated NDVI values decreased by 9.89–31.08, 38.16–47.47 and 61.90–66.71%, respectively. It results to the decrease of LAI by 39.76–74.34, 85.85–93.64 and 94.61–98.51%, and reduction of FPAR and APAR by 10.16–37.47, 39.21–57.24 and 63.60–80.44%. In addition, the increased minimum visible reflectance during 580–680 nm leads to the decrease of estimated aboveground biomass by 14.62, 48.86 and 56.84%, and reduction of estimated autotrophic respiration by 10.32, 39.11 and 46.95%. Ultimately, the caterpillar outbreak results to the directly underestimation of NPP by 10.01–64.63, 39.32–75.37 and 80.26–100% for light, moderate and severe samples compared with healthy. Furthermore, such impacts of forest insect disturbances should be accounted for in NPP modeling to reduce the uncertainties of estimation.     

Development and Application of Cloned DNA Probes for Clavibacter xyli subsp. xyli, the Causal Agent of Sugarcane Ratoon Stunting

Eco RI restriction fragments of genomic DNA from Clavibacter xyli subsp. xyli (CXX) were ligated with plasmid pUC18 and cloned in Escherichia coli JM109. The cloned DNA inserts from recombinant plasmids were Eco RI-excised and labeled with non-radioactive digoxigenin and used as probes. Ten specific DNA probes, RSD3, 15, 30, 31, 32, 35, 37, 41, 71, and 73 were selected for disease detection and pathogen differentiation. In the specificity tests, all of the 10 CXX DNA, probes differentiated Clavibacter xyli from other bacteria specifically. Seven out of the 10 CXX probes crossreacted with C. x. subsp. cynodontis (CXC) very weakly under moderate stringency wash conditions of hybridization. In the sensitivity tests, all of the 10 DNA probes detected the homologous DNA of CXX from 0.19 to 0.75 ng. To detect various cell numbers of CXX, the DNA probes detected 10⁴ to 10⁵ cells effectively. In Southern hybridizations, distinctly different band patterns were shown when the probes hybridized with DNA from CXX and CXC. Among these probes, RSD3, 15, 30, 31, 35, 37, and 71, efficiently detected CXX present in the sap collected from symptomless sugarcane.     

Linkage and association mapping reveals the genetic basis of brown fibre (Gossypium hirsutum)

Brown fibre cotton is an environmental‐friendly resource that plays a key role in the textile industry. However, the fibre quality and yield of natural brown cotton are poor, and fundamental research on brown cotton is relatively scarce. To understand the genetic basis of brown fibre cotton, we constructed linkage and association populations to systematically examine brown fibre accessions. We fine‐mapped the brown fibre region, Lc₁, and dissected it into 2 loci, qBF‐A07‐1 and qBF‐A07‐2. The qBF‐A07‐1 locus mediates the initiation of brown fibre production, whereas the shade of the brown fibre is affected by the interaction between qBF‐A07‐1 and qBF‐A07‐2. Gh_A07G2341 and Gh_A07G0100 were identified as candidate genes for qBF‐A07‐1 and qBF‐A07‐2, respectively. Haploid analysis of the signals significantly associated with these two loci showed that most tetraploid modern brown cotton accessions exhibit the introgression signature of Gossypium barbadense. We identified 10 quantitative trait loci (QTLs) for fibre yield and 19 QTLs for fibre quality through a genome‐wide association study (GWAS) and found that qBF‐A07‐2 negatively affects fibre yield and quality through an epistatic interaction with qBF‐A07‐1. This study sheds light on the genetics of fibre colour and lint‐related traits in brown fibre cotton, which will guide the elite cultivars breeding of brown fibre cotton.     

Arabidopsis ANGUSTIFOLIA3 (AN3) is associated with the promoter of CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) to regulate light‐mediated stomatal development

Light signals are perceived by multiple photoreceptors that converge to suppress the RING E3 ubiquitin ligase CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) for the regulation of stomatal development. Thus, COP1 is a point of integration between light signaling and stomatal patterning. However, how light signaling is collected into COP1 for the production and spacing of stomata is still unknown. Here, we report that the loss‐of‐function mutant of ANGUSTIFOLIA3 (AN3) delays asymmetric cell division, which leads to decreased stomatal index. Furthermore, overexpression of AN3 accelerates asymmetric cell division, which results in clusters of stomata. In addition, the stomatal development through AN3 regulation is mediated by light signaling. Finally, we find that an3 is a light‐signaling mutant, and that AN3 protein is light regulated. Self‐activation by AN3 contributes to the control of AN3 expression. Thus, AN3 is a point of collection between light signaling and stomatal patterning. Target‐gene analysis indicates that AN3 is associated with COP1 promoter for the regulation of light‐controlling stomatal development. Together, these components for regulating stomatal development form an AN3–COP1–E3 ubiquitin ligase complex, allowing the integration of light signaling into the production and spacing of stomata.     

Differential long-term neuroadaptations of glutamate receptors in the basolateral and central amygdala after withdrawal from cocaine self-administration in rats

Humans and laboratory animals remain highly vulnerable to relapse to cocaine-seeking after prolonged periods of withdrawal from the drug. It has been hypothesized that this persistent cocaine relapse vulnerability involves drug-induced alterations in glutamatergic synapses within the mesolimbic dopamine reward system. Previous studies have shown that cocaine self-administration induces long-lasting neuroadaptations in glutamate neurons of the ventral tegmental area and nucleus accumbens. Here, we determined the effect of cocaine self-administration and subsequent withdrawal on glutamate receptor expression in the amygdala, a component of the mesolimbic dopamine system that is involved in cocaine seeking and craving induced by drug-associated cues. Rats were trained for 10 days to self-administer intravenous cocaine (6 h/day) or saline (a control condition) and were killed after one or 30 withdrawal days. Basolateral and central amygdala tissues were assayed for protein expression of the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor subunits (GluR1 and GluR2) and the NMDA receptor subunits (NR1, NR2A and NR2B). In the basolateral amygdala, GluR1 but not GluR2 levels were increased on days 1 and 30, NR2A levels were increased on day 1, and NR2B levels were decreased on day 30 of withdrawal from cocaine. In the central amygdala, GluR2 but not GluR1 levels were increased on days 1 and 30, NR1 levels were increased on day 30 and NR2A or NR2B levels were not altered after withdrawal from cocaine. These results indicate that cocaine self-administration and subsequent withdrawal induces long-lasting and differential neuroadaptations in basolateral and central amygdala glutamate receptors.     

The role of salicylic acid and carrot embryogenic callus extracts in somatic embryogenesis of naked oat (Avena nuda)

Enhanced somatic embryogenesis and plant regeneration have been obtained using young leaf bases of naked oat (Avena nuda) as explants by including salicylic acid (SA) and carrot embryogenic callus extracts (CECE) in media. A 5- and 4-fold improvement was achieved in somatic embryogenesis and plant regeneration on the corresponding media supplemented with 0.5 mM SA and CECE as compared to control, respectively. Some physiological and biochemical changes were assayed in both embryogenic callus (EC) and non-embryogenic callus (NEC). The results indicated that superoxide dismutase activity was stimulated and catalases and ascorbate peroxidase activities were inhibited, while the O₂ ^- (superoxide anion) content was reduced and the hydrogen peroxide level was promoted in EC compared with NEC. Reduced malondialdehyde content and relative electrolyte leakage were also detected in EC.     

Matrix‐glycoprotein interactions required for budding of a plant nucleorhabdovirus and induction of inner nuclear membrane invagination

Nucleorhabdoviruses such as Sonchus yellow net virus (SYNV) replicate in the nuclei and undergo morphogenesis at the inner nuclear membrane (IM) in plant cells. Mature particles are presumed to form by budding of the Matrix (M) protein‐nucleocapsid complexes through host IMs to acquire host phospholipids and the surface glycoproteins (G). To address mechanisms underlying nucleorhabdovirus budding, we generated recombinant SYNV G mutants containing a truncated amino‐terminal (NT) or carboxyl‐terminal (CT) domain. Electron microscopy and sucrose gradient centrifugation analyses showed that the CT domain is essential for virion morphogenesis whereas the NT domain is also required for efficient budding. SYNV infection induces IM invaginations that are thought to provide membrane sites for virus budding. We found that in the context of viral infections, interactions of the M protein with the CT domain of the membrane‐anchored G protein mediate M protein translocation and IM invagination. Interestingly, tethering the M protein to endomembranes, either by co‐expression with a transmembrane G protein CT domain or by artificial fusion with the G protein membrane targeting sequence, induces IM invagination in uninfected cells. Further evidence to support functions of G‐M interactions in virus budding came from dominant negative effects on SYNV‐induced IM invagination and viral infections that were elicited by expression of a soluble version of the G protein CT domain. Based on these data, we propose that cooperative G‐M interactions promote efficient SYNV budding.