Biomass,production and nutrient distribution of a natural oak forest in central Korea

Biomass, production, and nutrient distribution of a pure Quercus variabilis Bl. stand (stand 1) and two mixed Q. variabilis–Q. mongolica Fisch. stands (stand 2 and 3) were investigated in central Korea. Stand 1 naturally occurred on a site with a southern aspect while stand 2 and stand 3 occurred on sites with a northern aspect. Total (overstory+understory vegetation) biomass (tha^-1) and annual production (tha^–1year^–1) were 137.8 and 11.1 for stand 1, 216.2 and 16.6 for stand 2, and 253.3 and 19.7 for stand 3. Nutrient contents (kgha^–1) in the vegetation were distributed as follows: K, 478–860; N, 471–839; Ca, 428–791; Mg, 72–125; Na, 77–141; and P, 37–71, and were greatest in stand 3 followed by stand 2, and stand 1. Stand density influenced the differences in biomass, annual production and nutrient contents in the vegetation. Forest floor dry mass and N content (kgha^–1) were 13400 and 169 for stand 1, 10400 and 133 for stand 2, and 11200 and 127 for stand 3. Total amounts of N, P and Na in the ecosystem were greatest in the upper 40cm of mineral soil followed by the vegetation and forest floor. However, the vegetation contained a greater amount of K than the mineral soil. It appeared that microenvironments, such as, aspect influenced the distribution of natural oak species within a relatively small area and resulted in differences in biomass, production and nutrient distribution among the stands.     

Functional analysis of the Alternaria brassicicola non-ribosomal peptide synthetase gene AbNPS2 reveals a role in conidial cell wall construction

Alternaria brassicicola is a necrotrophic pathogen causing black spot disease on virtually all cultivated Brassica crops worldwide. In many plant pathosystems fungal secondary metabolites derived from non-ribosomal peptide synthetases (NPSs) are phytotoxic virulence factors or are antibiotics thought to be important for niche competition with other micro-organisms. However, many of the functions of NPS genes and their products are largely unknown. In this study, we investigated the function of one of the A. brassicicola NPS genes, AbNPS2 . The predicted amino acid sequence of AbNPS2 showed high sequence similarity with A. brassicae , AbrePsy1, Cochliobolus heterostrophus , NPS4 and a Stagonospora nodorum NPS. The AbNPS2 open reading frame was predicted to be 22 kb in length and encodes a large protein (7195 amino acids) showing typical NPS modular organization. Gene expression analysis of AbNPS2 in wild-type fungus indicated that it is expressed almost exclusively in conidia and conidiophores, broadly in the reproductive developmental phase. AbNPS2 gene disruption mutants showed abnormal spore cell wall morphology and a decreased hydrophobicity phenotype. Conidia of abnps2 mutants displayed an aberrantly inflated cell wall and an increase in lipid bodies compared with wild-type. Further phenotypic analyses of abnps2 mutants showed decreased spore germination rates both in vitro and in vivo , and a marked reduction in sporulation in vivo compared with wild-type fungus. Moreover, virulence tests on Brassicas with abnps2 mutants revealed a significant reduction in lesion size compared with wild-type but only when aged spores were used in experiments. Collectively, these results indicate that AbNPS2 plays an important role in development and virulence.     

Brain-derived neurotrophic factor-like neuropeptide is secreted as a neurohormone from specific brain neurons into the corpus allatum in the silkworm Bombyx mori

The aim of this study was to investigate the secretion of brain‐derived neurotrophic factor (BDNF)‐like neuropeptide in the silkworm, Bombyx mori , by using immunocytochemical techniques on the brain and retrocerebral complex of fifth instar larvae. In the brain, four pairs of median neurosecretory cell (MNC) bodies and six pairs of lateral neurosecretory cell (LNC) bodies had distinct immunoreactivities to this peptide, suggesting that this peptide is produced from two types of brain neuron. These reactivities were much stronger in the MNC than in the LNC. Labeled MNC projected their axons into the contralateral corpora allata, to which axons of labeled MNC were eventually innervated, through decussation in the median region, contralateral nerve corporis cardiaci I and nerve corpora allata I. Labeled LNC extended their axons into the ipsilateral corpora allata to be innervated through the ipsilateral nerve corporis cardiaci II and nerve corpora allata I. These results suggest that BDNF is secreted as a neurohormone from MNC and LNC of the brain into the corpora allata.     

Ecological synopsis for Chironomus flaviplumus (Diptera: Chironomidae) in the Jung-rang stream

In this study, we conducted field sampling to assess the relative influences of water and substrate quality on benthic macroinvertebrate communities living in the Jung‐rang stream, Korea. We collected macroinvertebrates and assessed physicochemical variables from three sites in the stream between May 2001 and January 2002. Sites were located approximately within 20 km from the headwater. The structure of the benthic macroinvertebrate communities may be strongly affected by the physical conditions inherent to the environment in which they live. In this stream, we detected profound differences in water temperature (18 ～ 19.75°C), the concentrations of suspended solids (3.935 ～ 7.87 mg/L), and demand for chemical oxygen (10.575 ～ 14.425 mg/L). Nonylphenol concentrations ranging from 0.375 to 0.55 ng/mL were found in the water, and the sediments were measured to contain between 2.45 and 3.425 ng/mL. We identified a total of 20 macroinvertebrate species, including seven species of Chironomidae, the most abundant of which was Chironomus flaviplumus. At none of the sites did we find any significant differences in the structure of the communities. Using canonical correspondence analysis for the relation of species and environmental variables, chemical oxygen demand and suspended sediment gradients (SS) had significant preferences for site 1 with SS. The results of our study suggest that physico‐chemical variables exerted complex effects on the structure of the benthic community in the Jung‐rang stream. This study supports the contention that physico‐chemical analyses as well as community analysis are valuable tools to assess the effect of pollution on the ecological condition of a stream. Chironomids, in particular, showed a high degree of tolerance against contaminants.     

Looking for Identity in the Muslim World

Dramas of Nationhood: The Politics of Television in Egypt. Lila Abu-Lughod. Chicago: University Chicago Press, 2005. 319 pp.
Memories of State: Politics, History, and Collective Identity in Modern Iraq. Eric Davis. Berkeley: University of California Press, 2005. 385 pp.
Religion, Social Practice, and Contested Hegemonies: Reconstructing the Public Sphere in Muslim Majority Societies. Armando Salvatore and Mark LeVine, eds. New York: Palgrave Macmillan, 2005. 249 pp.
Contesting Rituals: Islam and Practices of Identity Making. Pamela Stewart and Andrew Strathern, eds. Durham, NC: Carolina Academic Press, 2005. 239 pp.     

Taxonomic Study of Korean Chrysochraontini (Orthoptera: Acrididae: Gomphocerinae)

Five species of Korean Chrysochraontini are recognized through the taxonomic investigation. Among them Chrysochraon dispar major Uvarov, 1925 is newly recorded from North Korea, and Euthystira pavlovskii Bey‐Bienko, 1954 is synonymized under Mongolotettix japonicus (Bolívar, 1898). A key is provided, and morphological variations of M. japonicus are discussed.     

Microstructural Analysis of the Capture Thread Spinning Apparatus in Orb Web Spiders

The microstructural characteristics of the capture thread production from silk glands in the orb web spiders were analyzed using scanning and transmission electron microscopes. Sticky and gluey capture threads of the web are originated from the silks of two flagelliform glands and four aggregate glands. They supply precursors of the secretory silks to a pair of characteristic “triad” spinning units on the posterior spinnerets. The aggregate gland is composed of large and multi‐lobed secretory region and thick excretory duct surrounded by large irregular nodules. The excretory duct of this gland basically consists of three superposed types of cells which are inner columnar epithelium, nodule forming cells and outer connectives. The nodules contain numerous mitochondria and glycogen particles within their cytoplasm and they are surrounded by the same sheath of thin connective tissues. Secretory region of the aggregate gland which produce water‐soluble components of the capture thread comprises discrete secretory vesicles and extensive rough endoplasmic reticulum. Characteristically, secretory droplets are formed without involvement of the Golgi complexes, suggesting that they do not play an important role in the processing of the capture threads. However the electron densities and internal textures of the granules are observed with diverse according to their maturation level. Finally, the secretory products are released by the mechanism of apocrine secretion losing part of their cytoplasm during this process.     

Tabanid Flies (Diptera: Tabanidae) of the Northern Part of Gyeonggi Province, Republic of Korea

Tabanid flies were surveyed using New Jersey light traps and Mosquito Magnet® traps at US Army installations and training sites in the northern part of Gyeonggi Province, Republic of Korea. A total of 344 tabanid flies, comprising 14 species and 5 genera, were collected from June to August during 2003‐2004. Dominant species were Chrysops vanderwulpi (57.3%), Haematopota sinensis (29.1%), Haematopota koryoensis (4.4%) and Tabanus mandarinus (2.3%). Mosquito Magnet traps that generated CO₂through the combustion of propane gas were nearly 6 times more effective in collecting tabanid flies than New Jersey light traps. Based on Mosquito Magnet trap collections, peak populations occurred from mid‐June to early July.;     

<Emphasis Type="Italic">Muscadinia rotundifolia</Emphasis> ‘Noble’ defense response to <Emphasis Type="Italic">Plasmopara viticola</Emphasis> inoculation by inducing phytohormone-mediated stilbene accumulation

Downy mildew (DM), one of the most devastating grape diseases worldwide, is caused by the biotrophic oomycete Plasmopara viticola (Pv). In general, grapevine responds to Pv infection with the accumulation of phytoalexins as part of the innate immune system, and diverse phytoalexins are induced on grapevines with different DM-resistance levels in response to Pv invasion. However, the regulation of phytoalexin biosynthesis during grapevine against Pv is still unclear. Herein, we detected stilbenes by UPLC-ESI-MS/MS and found that resveratrol was accumulated to higher level and earlier in the DM-immune Muscadinia rotundifolia ‘Noble’ than that in the DM-susceptible Vitis vinifera ‘Thompson Seedless’ after Pv inoculation. Additionally, a considerable amount of pterostilbene and ε-viniferin was found in ‘Noble’, while a little was detected in ‘Thompson Seedless’. Resveratrol was glycosylated into piceid both in ‘Noble’ and ‘Thompson Seedless’ after Pv inoculation. The qPCR analysis of gene expression indicated that the resveratrol-synthesis gene (STS) was induced by Pv inoculation earlier in ‘Noble’ than that in ‘Thompson Seedless’, while the pterostilbene-synthesis gene (ROMT) was induced in ‘Noble’ but not in ‘Thompson Seedless’ at all. The piceid-synthesis gene (GT) was generally up-regulated in both cultivars. Sequence analysis of STS, ROMT, and GT promoters revealed that they contained cis-regulatory elements responsive to phytohormones and pathogens. Following Pv inoculation, the level of SA, MeJA, and ABA was found to be consistently higher in ‘Noble’ than those in ‘Thompson Seedless’. The results of exogenous hormone elicitation further demonstrated that the accumulation of stilbenes was regulated by phytohormones. The earlier and higher accumulation of phytohormones and consequent induction of stilbene synthesis may play an important role in grapevine defense against downy mildew disease.