Fermentation of brined turnip roots using Lactobacillus plantarum and Leuconostoc mesenteroides starter cultures

The controlled fermentation of turnip slices using Lactobacillus plantarum or Leuconostoc mesenteroides as starter cultures led to earlier acid production and earlier and more pronounced inhibition of Enterobacteriaceae than with uninoculated (natural) fermentation. Unlike the natural fermentation, the controlled fermentations did not show a yeast secondary fermentation and also had a better colour. Due to its ability to produce higher amounts of acid, the use of Lact. plantarum is more desirable than of Leuc. mesenteroides.     

Novel Fraction Collector for Studying the Oviposition Rhythm in the Turnip Moth

Turnip moths, Agrotis segetum (Schiff.) (Lepidoptera: Noctuidae), were held in a transparent plastic box with a window opening to a rotating paper drum upon which the females could lay eggs. A novel fraction collector, consisting of a standard 24-hr wall timer and simple electronic circuit, served to rotate the paper in hourly increments. The entire apparatus was housed in an environmental chamber on a 16 hr light: 8 hr dark photoperiod at constant 23.7°C and 55% r.h. Under these conditions a circadian rhythm of egg laying was indicated with a mean activity time 0.2 hr before dark and standard deviation of 2.1 hr. The relative egg productions during the second to seventh day of oviposition peaked on the third day. Differences in the circadian rhythms of mating and oviposition are considered in terms of ecological fitness.     

Signaling requirements and role of salicylic acid in HRT- and rrt-mediated resistance to turnip crinkle virus in Arabidopsis

Inoculation of turnip crinkle virus (TCV) on the resistant Arabidopsis ecotype Di-17 elicits a hypersensitive response (HR), which is accompanied by increased expression of pathogenesis-related (PR) genes. Previous genetic analyses revealed that the HR to TCV is conferred by HRT, which encodes a coiled-coil (CC), nucleotide-binding site (NBS) and leucine-rich repeat (LRR) class resistance (R) protein. In contrast to the HR, resistance to TCV requires both HRT and a recessive allele at a second locus designated rrt. Here, we demonstrate that unlike most CC-NBS-LRR R genes, HRT/rrt-mediated resistance is dependent on EDS1 and independent of NDR1. Resistance is also independent of RAR1 and SGT1. HRT/rrt-mediated resistance is compromised in plants with reduced salicylic acid (SA) content as a consequence of mutations eds5, pad4, or sid2. By contrast, HR is not affected by mutations in eds1, eds5, pad4, sid2, ndr1, rar1, or sgt1b. Resistance to TCV is restored in both SA-deficient Di-17 plants expressing the nahG transgene and mutants containing the eds1, eds5, or sid2 mutations by exogenous application of SA or the SA analog benzo(1,2,3)thiadiazole-7-carbothioic acid (BTH). In contrast, SA/BTH treatment failed to enhance resistance in HRT pad4, Col-0, or hrt homozygous progeny of a cross between Di-17 and Col-0. Thus, HRT and PAD4 are required for SA-induced resistance. Exogenously supplied SA or high endogenous levels of SA, due to the ssi2 mutation, overcame the suppressive effects of RRT and enhanced resistance to TCV, provided the HRT allele was present. High levels of SA upregulate HRT expression via a PAD4-dependent pathway. As Col-0 transgenic lines expressing high levels of HRT were resistant to TCV, but lines expressing moderate to low levels of HRT were not, we conclude that SA enhances resistance in the RRT background by upregulating HRT expression. These data suggest that the HRT-TCV interaction is unable to generate sufficient amounts of SA required for a stable resistance phenotype, and the presence of rrt possibly corrects this deficiency.     

Acidic dileucine motifs in the cylindrical inclusion protein of turnip mosaic virus are crucial for endosomal targeting and viral replication

Previously we reported that the multifunctional cylindrical inclusion (CI) protein of turnip mosaic virus (TuMV) is targeted to endosomes through the interaction with the medium subunit of adaptor protein complex 2 (AP2β), which is essential for viral infection. Although several functionally important regions in the CI have been identified, little is known about the determinant(s) for endosomal trafficking. The CI protein contains seven conserved acidic dileucine motifs [(D/E)XXXL(L/I)] typical of endocytic sorting signals recognized by AP2β. Here, we selected five motifs for further study and identified that they all were located in the regions of CI interacting with AP2β. Coimmunoprecipitation assays revealed that alanine substitutions in the each of these acidic dileucine motifs decreased binding with AP2β. Moreover, these CI mutants also showed decreased accumulation of punctate bodies, which enter endocytic-tracking styryl-stained endosomes. The mutations were then introduced into a full-length infectious clone of TuMV, and each mutant had reduced viral replication and systemic infection. The data suggest that the acidic dileucine motifs in CI are indispensable for interacting with AP2β for efficient viral replication. This study provides new insights into the role of endocytic sorting motifs in the intracellular movement of viral proteins for replication.     

苦豆子生物碱对萝卜蚜的毒力及其对几种酯酶的影响

苦豆子Sophoraalopecuroids（L．）的次生代谢物质为喹诺里西定生物碱类。本研究明确了该生物碱中的野靛碱对萝卜蚜（Lipaphiserysimi）有很高的毒杀作用,对其无翅成蚜的致死中浓度（LC50,浸渍法）为（4325±2．12）mg／L,优于著名的杀蚜生物碱毒黎碱和烟碱,两者对该试虫的LC50分别为（684．70±2．28）mg／L和（1090．65±2．01）mg／L。用小菜蛾（Plutellaxylostella）幼虫作试虫,得知苦豆子7种主要生物碱对昆虫的乙酰胆碱酯酶（AChE）有抑制作用,其抑制程度排序为：总碱＞野靛碱＞槐胺碱＞槐定碱＞槐果碱＞氧化苦参碱＞苦参碱＞苦豆碱。野靛碱和苦豆碱对α-乙酸萘酯酶、α-乙酸萘酯羧酸酯酶及酯酶同功酶的活性亦表现不同程度的抑制作用。     

Multi-domain Packing in the Aminoacylatable 3′ End of a Plant Viral RNA

Turnip yellow mosaic virus (TYMV) contains a tRNA-like structure (TLS) in its 3′ untranslated region (3′ UTR).  This highly structured element induces valylation of the viral RNA by host cell enzymes and is important for virus proliferation. Directly upstream of the TYMV TLS is an upstream pseudoknot domain (UPD) that has been considered to be structurally distinct from the TLS.  However, using a combination of functional, biochemical, and biophysical assays, we show that the entire 3′ UTR of the viral genome is a single structured element in the absence of cellular protein.  This packing architecture stabilizes the RNA structure and creates a better substrate for aminoacylation, and thus the UPD and TLS are functionally and structurally coupled.  It has been proposed that the TYMV TLS acts as a molecular switch between translation and replication. Our results suggest that this putative switch could be based on structural changes within the global architecture of the UTR induced by interactions with the ribosome. The TYMV TLS·UPD might demonstrate how RNA structural plasticity can play a role in regulation of biological processes.     

1-Cyano-3,4-epithiobutane: A major product of glucosinolate hydrolysis in seeds from certain varieties of Brassica campestris

A new hydrolysis product derived from 3-butenylglucosinolate in seeds of certain strains of Brassica campestris Yellow Sarson is described. The structure, 1-cyano-3,4-epithiobutane is proposed. If the seeds are heated at 115° for 30 min before hydrolysis, 3-butenyl isothiocyanate is the main product.     

Impact of treated municipal wastewater irrigation on turnip (Brassica rapa)

The effect of treated municipal wastewater on the roots and the leaves of turnip was studied to compare the 50% and 100% wastewater of 34 ml/d Sewage Treatment Plant (STP) with different doses of potassic fertilizers. Turnip (Brassica rapa) was used as a test plant. A pot experiment was conducted, using a factorial randomized block design to investigate the growth and translocation of heavy metals to the leaves and the roots of turnip. The concentration of heavy metal in wastewater used for irrigation was within the limits. However, the concentration in the plant parts showed a significant rise due to continuous use of wastewater. The concentration of heavy metals in leaves and roots was at excessive levels at 40 and 55 days after sowing (DAS), while at 70 DAS, metal concentration was comparatively low. The range of heavy metals in wastewater irrigated plants was Cd = 1–16.3, Ni = 0–136, Fe = 263–1197, Cu = 0–18, Mn = 37–125, and Zn = 42–141 mg/kg. Concentration of heavy metals in plants was found in the order of Fe>Zn>Ni>Mn>Cu>Cd.