Biological control of bacterial spot disease and plant growth-promoting effects of lactic acid bacteria on pepper

In our previous studies, we observed the biological control effect of lactic acid bacteria strains (LABs) KLF01, KLC02 and KPD03 against different plant pathogenic bacteria in vitro against Ralstonia solanacearum, and strains KLF01 and KLC02 against Pectobacterium carotovorum under greenhouse and field experiments, respectively. In this study, we observed the efficacy of these bacteria against bacterial spot pathogen (Xanthomonas campestris pv. vesicatoria) and their plant growth-promoting activities in pepper (Capsicum annuum L. var. annuum), under greenhouse and field conditions. LABs significantly (P < 0.05) reduced bacterial spot on pepper plants in comparison to untreated plants in both the greenhouse and the field experiments. The plant growth-promoting effect of LABs on pepper varied; some strains had a significant effect on growth promotion (P < 0.05) compared with untreated plants, while some showed no significant effect in the greenhouse and field experiments. Additionally, LABs were able to colonise roots, produce indole-3-acetic acid (IAA), siderophores and solubilise phosphate. These findings indicate that application of LABs could provide a promising alternative for the management of bacterial spot disease in pepper plants and could therefore be used as a healthy plant growth-promoting agent.     

The Pitcairn Islands, South Pacific Ocean: plate tectonic and climatic contexts

The remote Pitcairn Group in the South Pacific Ocean comprises a volcanic island (Pitcairn Island), two low coral atolls (Oeno, Ducie) and a raised coralline island (Henderson Island). The geological history of these islands, on anomalously thin oceanic lithosphere, is related to the development of two subparallel island chains (Oeno-Henderson-Ducie; Pitcairn) associated with intra-Pacific plate 'hotspot' activity; the surface manifestation of this activity has been partly determined by structural lineations in the plate inherited from past plate history. The climate of the Pitcairn Islands is determined by the position of the subtropical high pressure system and the South Pacific Convergence Zone. Variations in the strength of this atmospheric circulation system, measured by changes in the Southern Oscillation index of pressure difference, provide a partial explanation of the long-term variability of mean annual rainfall at Pitcairn Island. Knowledge of past climates in the Pitcairn Group remains speculative. Maps of the Pitcairn Islands and a report of climate at Henderson Island (2/91-1/92) are included in the paper.     

Effect of intraperitoneal administration of granulocyte/macrophage-colony-stimulating factor in rats on omental milky-spot composition and tumoricidal activity in vivo and in vitro

 Milky spots in the greater omentum are small accumulations of leucocytes that consist mainly of macrophages and have recently shown to be a selective dissemination site of intraperitoneal (i. p.) inoculated tumour cells. However, milky-spot macrophages show tumoricidal activity and may, therefore, be an excellent source of effector cells suited for local immunotherapy. In the present study we first examined whether granulocyte/macrophage- colony-stimulating factor (GM-CSF) treatment of isolated milky-spot macrophages affects the cytotoxicity against syngeneic colon carcinoma cells (CC531) in vitro. Secondly, we studied the influence of intraperitoneal GM-CSF administration on the number and antitumour activity of milky-spot and peritoneal macrophages. All studies were performed in Wag/Rij rats in which a syngeneic colon carcinoma cell line (CC531) is available. The results of the in vitro study showed that GM-CSF treatment of the omental macrophages led to an increased cytotoxicity against the tumour cell line. Intraperitoneal administration of 1000 U GM-CSF daily for 7 consecutive days demonstrated both an enhanced antitumour activity of the milky-spot macrophages and an increase in the milky-spot macrophage population. An increase in the proliferative capacity, according to bromodeoxyuridine incorporation, was shown in the milky-spot macrophages. Taking into account both the enhanced macrophage number and their enhanced activity upon i. p. GM-CSF treatment, the milky-spot macrophages may provide a rationale for local intraperitoneal immunotherapy in the prevention of intra-abdominal tumour growth. Received: 11 April 1996 / Accepted: 21 May 1996     

The inheritance of a wingless character in the 2spot ladybird (Adalia bipunctata)

A viable wingless 2spot ladybirdAdalia bipunctata (L.) was found in the wild. Breeding through four generations revealed that the wingless trait was controlled by a recessive allele which displays variable levels of expression. The wingless ladybird is discussed in relation to its potential as a biocontrol agent. One ladybird also occurred in this stock which is suggestive of a supergene controlling the colour polymorphism in this species.     

Structural model studies for the high-valent intermediate Q of methane monooxygenase from broken-symmetry density functional calculations

Mössbauer isomer shift parameters have been obtained for both density functional theory (DFT) OPBE and OLYP functionals by linear regressions between the measured isomer shifts and calculated electron densities at Fe nuclei for a number of Fe^2+,2.5+ and Fe^{2.5+,3+,3.5+,4+} complexes grouped separately. The calculated isomer shifts and quadrupole splittings on the sample Fe complexes from OPBE and OLYP functionals are similar to those of PW91 calculations [J. Comput. Chem. 27 (2006) 1292], however the fit parameters from the linear regressions differ between PW91 and OPBE, OLYP. Four models for the active site structure of intermediate Q of the hydroxylase component of soluble methane monooxygenase (MMOH) have been studied, using three DFT functionals OPBE, OLYP, and PW91, incorporated with broken-symmetry methodology and the conductor-like screening (COSMO) solvation model. The calculated properties, including optimized geometries, electronic energies, pK_a’s, Fe net spin populations, and Mössbauer isomer shifts and quadrupole splittings, have been reported and compared with available experimental values. The high-spin antiferromagnetically (AF) coupled Fe⁴⁺ sites are correctly predicted by OPBE and OLYP methods for all active site models. PW91 potential overestimates the Fe-ligand covalencies for some of the models because of spin crossover. Our calculations and data analysis support the structure (our current model II shown in Fig. 8) proposed by Friesner and Lippard’s group [J. Am. Chem. Soc. 123 (2001) 3836-3837], which contains an Fe⁴⁺(μ-O)₂Fe⁴⁺ center, one axial water which also H-bonds to both side chains of Glu243 and Glu114, and one bidentate carboxylate group from the side chain of Glu144, which is likely to represent the active site of MMOH-Q. A new model structure (model IV shown in Fig. 9), which has a terminal hydroxo and a protonated His147 which is dissociated from a nearby Fe, is more asymmetric in its Fe(μ-O)₂Fe diamond core, and is another very good candidate for intermediate Q.     

对虾白斑杆状病毒DNA聚合酶调控序列的克隆

为了揭示对虾白斑杆状病毒的致病机理,将该病毒基因组中推测的DNA聚合酶上游调控序列克隆进荧光素酶报告基因载体中,以便寻找一个能表达该病毒基因的细胞系统.     

The historical biogeography of co-evolution: emerging infectious diseases are evolutionary accidents waiting to happen

Ecological fitting refers to interspecific associations characterized by ecologically specialized, yet phylogenetically conservative, resource utilization. During periods of biotic expansion, parasites and hosts may disperse from their areas of origin. In conjunction with ecological fitting, this sets the stage for host switching without evolving novel host utilization capabilities. This is the evolutionary basis of emerging infectious diseases (EIDs). Phylogenetic analysis for comparing trees (PACT) is a method developed to delineate both general and unique historically reticulated and non‐reticulated relationships among species and geographical areas, or among parasites and their hosts. PACT is based on ‘Assumption 0’, which states that all species and all hosts in each input phylogeny must be analysed without modification, and the final analysis must be logically consistent with all input data. Assumption 0 will be violated whenever a host or area has a reticulated history with respect to its parasites or species. PACT includes a Duplication Rule, by which hosts or areas are listed for each co‐evolutionary or biogeographical event affecting them, which satisfies Assumption 0 even if there are reticulations. PACT maximizes the search for general patterns by using Ockam's Razor – duplicate only enough to satisfy Assumption 0. PACT applied to the host and geographical distributions of members of two groups of parasitic helminths infecting anthropoid primates indicates a long and continuous association with those hosts. Nonetheless, c. 30% of the host associations are due to host switching. Only one of those involves non‐primate hosts, suggesting that most were constrained by resource requirements that are phylogenetically conservative among primates (ecological fitting). In addition, most of the host switches were associated with episodes of biotic expansion, also as predicted by the ecological fitting view of EIDs.