Genetic organization and sequence of the rfb gene cluster of Yersinia enterocolitica serotype O:3: similarities to the dTDP-L-rhamnose biosynthesis pathway of Salmonella and to the bacterial polysaccharide transport systems

The Yersinia enterocolitica O:3 lipopotysaccharide O-antigen is a homopotymer of 6-deoxy-L-altrose. The cloned rfb region was sequenced, and 10 open reading frames were identified. Transposon mutagenesis, deletion analysis and transcomplementatton experiments showed that eight of the genes, organized into two operons, rfbABC and rfbDEFGH, are essential for 0-antigen synthesis. Functional tandem promoters were identified upstream of both operons. Of the deduced polypeptides RfbA, RfbF and RfbG were similar to Salmonella proteins involved in the dTDP-l -rhamnose biosynthesis. Rhamnose and 6-deoxy-l -altrose are C3-epimers suggesting that analogous pathways function in their biosynthesis. RfbD and RfbE were similar to capsular polysaccharide export proteins, e.g. KpsM and KpsT of Escherichia coli. This and transposon mutagenesis showed that RfbD and RfbE function as O-antigen exporters.     

Estimation of Genetic Divergence and Character Association Studies in Local and Exotic Diversity Panels of Soybean (<i>Glycine max</i> L.) Genotypes

The availability of favorable genetic diversity is a thriving vitality for the success of a breeding program. It provides a firm basis of selecting superior breeding lines for the development of high yielding crop genotypes. In this context, present investigation aimed to generate information on genetic divergence and character association in a diversity panel of 123 local and exotic soybean genotypes. Analysis of variance revealed significant response of the evaluated genotypes based on studied attributes. It depicted the probability of selecting desirable soybean genotypes by focusing on character association studies and genetic diversity analysis. Correlation analysis revealed that seed yield per plant showed high positive correlation with 100-seed weight followed by pods per plant and plant height. Furthermore, path coefficient analysis exposed that pods per plant had maximum direct contribution in seed yield per plant followed by 100-seed weight, days to flowering and SPAD measurement. Genotype named “G-10” showed maximum yield per plant followed by 24607, G-52, 24593, Arisoy, 24566, 17426, A-3127, 24570 and 24567. Genetic diversity analysis grouped the evaluated germplasm into 17 clusters. All clusters showed zero intra-cluster variability; while inter-cluster divergence ranged from 9.00 to 91.11. Cluster V showed maximum inter-cluster distance with cluster XII followed by that of between V and VIII. Moreover, cluster IV with superior genotypes (G-10, 24607, 24593 and 24566), VI (17426 and 24567), XIII (24570) and X (Arisoy and G-52) showed above mean values for most of the studied characters. Overall, the results of hybridization between the superior genotypes of these cluster pairs might be useful for soybean breeding with improving agronomic traits and adaptability.     

Confirmation and quantification of strigolactones, germination stimulants for root parasitic plants Striga and Orobanche, produced by cotton

The germination stimulants for root parasitic plants Striga and Orobanche produced by cotton (Gossypium hirsutum L.) were examined in detail. Seeds of cotton were germinated and grown on glass wool wetted with sterile distilled water in sterile filter units. The root exudate was collected daily and extracted with ethyl acetate. Each of these ethyl acetate extracts was analyzed directly by high-performance liquid chromatography linked with tandem mass spectrometry (LC/MS/MS). The results demonstrate that cotton roots exuded strigol and strigyl acetate, but no other known strigolactones such as orobanchol and alectrol. The production of strigol was detected even in the root exudate collected during the first 24 h of incubation and reached a maximum 5-7 days later. The average exudation of strigol and strigyl acetate during the incubation period was ca. 15 and 2 pg/plant/day, respectively, indicating that strigol mainly contributed to germination stimulation by the cotton root exudate.     

Detoxification of the organophosphate nerve agent coumaphos using organophosphorus hydrolase immobilized on cellulose materials

Neurotoxic organophosphates (OPs) are widely used as pesticides and for public health purposes, as well as being nerve gases. As a result of the widespread use of these compounds for agriculture, large volumes of wastewater are generated. Additionally, there are large stockpiles of the nerve gases soman, sarin and VX in the United States and elsewhere around the world. Organophosphorus hydrolase (OPH) is an enzyme that catalyzes the hydrolysis of OP nerve agents. To date, however, the use of this enzyme in detoxification processes has been rather limited due to the high cost of its purification and short catalytic half-life. This paper reports the development of a cost-effective method for the production and immobilization of OPH in a pilot application in an enzyme bioreactor column for detoxification of paraoxon and coumaphos in contaminated wastewaters. A fusion between OPH and a cellulose binding domain that binds selectively to cellulose was generated to allow one-step purification and immobilization of OPH on cheap and abundantly available cellulose immobilization matrices. When packed in a column bioreactor, the immobilized fusion enzyme was able to completely degrade coumaphos up to a concentration of 0.2 mM. However, stirring of OPH immobilized on cellulose materials resulted in complete OP degradation of 1.5 mM coumaphos. The bioreactor column degraded the compounds tested at high concentration, rapidly, and without loss of process productivity for about 2 months.     

A new Asphondylia species (Diptera: Cecidomyiidae) and a eulophid wasp (Hymenoptera) inducing similar galls on leaf buds of Schoepfia jasminodora (Schoepfiaceae), with reference to their ecological traits and a description of the new gall midge

Different gall inducers belonging to distinct insect orders are rarely known to induce similarly shaped galls on the same host plant organs. We report that Asphondylia tojoi Elsayed & Tokuda sp. nov. (Diptera: Cecidomyiidae) and Ceratoneura sp. (Hymenoptera: Eulophidae) induce galls on leaf buds of Schoepfia jasminodora Sieb. et Zucc. (Schoepfiaceae). We describe the gall midge species as new to science and report a phylogenetic analysis for known Japanese Asphondylia species. We also describe life histories of the two species, based on monthly surveys during 2015–2017: although both species are multivoltine, A. tojoi overwinters as first instars in galls, whereas Ceratoneura sp. possibly does so as adults outside the galls. In addition, the internal structure of galls differed between the two species. Galls containing A. tojoi consist of a single chamber with inner walls clearly covered with whitish fungal mycelia after the gall midges develop into second instars. Those containing the Ceratoneura sp. have multiple chambers with hard black inner walls. Although some eulophids are known to be inquilines of galls induced by Asphondylia species, we consider that the Ceratoneura sp. is probably a true gall inducer because of the different gall structure and absence of fungal mycelia in their galls. This is the first report detailing the annual life history of a Ceratoneura species. Asphondylia tojoi represents the first example of monophagous Asphondylia species with a multivoltine life history on a deciduous tree.     

Analysis of Methanogenic Archaeal and Sulphate Reducing Bacterial Populations in Deep Sediments of the Black Sea

In this study, the distribution, morphology and relative abundance of Sulfate Reducing Bacterial (SRB) and Methanogenic Archaeal (MA) populations in the Black Sea sediments were investigated by using in situ hybridization with fluorescently labeled rRNA-targeted oligonucleotide probes. Results were discussed with respect to the characteristics of sampling points. MA and SRB showed a great diversity in all sediment samples. Higher abundance of MA (20–30%) and SRB (30–35%) populations were observed within the sediments from deeper parts of the Black Sea than the shallower parts (10–11% MA and 13–14% SRB). Desulfobotulus, Desulfosarcina and Desulfococcus groups were the most commonly detected SRB groups in the Black Sea sediments. Relative percentage of these SRB groups within sediments from deeper parts of the Black Sea was in a range of 17–21% whereas that of was in a range of 4–5% within the sediments from the shallower parts. Order Methanococcales were the dominant methanogenic group in all samples. Relative percentages of order Methanococcales were in a range of 8–12% and 4–5% within sediments from deeper parts and the coastal parts of the Black Sea, respectively.