Diversity (polymorphism) of the meq gene in the attenuated Marek's disease virus (MDV) serotype 1 and MDV-transformed cell lines

The meq gene encoding a 339-amino-acid bZIP transactivator protein has been identified as a candidate oncogene of Marek's disease virus serotype 1 (MDV1), which induces malignant lymphomas in chickens. We have previously reported that, in addition to meq, L-meq, in which a 180-bp sequence is inserted into the region encoding the transactivation domain of meq, is also detected in chickens experimentally infected with MDV. To further analyze the diversity in meq, PCR was performed using a primer set which specifically amplify the proline-rich repeat (PRR) region in the transactivation domain of meq. In CVI988/R6, a vaccine strain of MDV1, and JM, an MDV1 strain attenuated by prolonged passage in vitro, a major band of a 0.8 kb corresponding to L-meq as well as a minor band of 0.6 kb corresponding to meq was detected by PCR. Furthermore, extra 0.5- and 0.3-kb bands, corresponding to genes termed as short meq (S-meq), and very short meq (VS-meq), respectively, were also detected. These genes were also detected in MDV-transformed cell lines, MSB1 and MTB1. In Md5, an oncogenic MDV1, attenuated by prolonged passage in vitro, the 0.6-kb meq was consistently detected, and 0.5-kb S-meq was occasionally detected. This diversity in meq was due to the difference in the copy number of the PRR region: L-meq and meq contained 9 and 6 copies of PRR while 4 and 2 copies of PRR were present in S-meq and VS-meq, respectively. Thus, the meq gene is polymorphic in the attenuated MDV1 and the MDV-transformed cell lines, and gene products from different meq genes may have different functions from each other.     

Distinguishable staining with neutral red for GFP-marked and GFP-nonmarked <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> strains simultaneously colonizing root surfaces

 Green fluorescent protein (GFP)-marked Fusarium oxysporum f. sp. melonis and nonmarked F. oxysporum f. sp. fragariae were stained with neutral red. The neutral red stained vacuoles of the fungi without disturbing GFP fluorescence in the cytoplasm. GFP-marked fungi showed fluorescent hyphae with dark-stained vacuoles, whereas nonmarked fungi were detected as nonfluorescent hyphae with dark-dotted vacuoles. Root colonization by these two fungi was monitored using this method. Microconidia attached similarly to the root surface and elongated vegetative hyphae. Only the pathogenic fungi invaded, causing necrosis at the inoculation site. Thus, the present method enabled us to track simultaneously the various formae speciales of F. oxysporum colonizing the root surface. Received: March 25, 2002 / Accepted: September 27, 2002     

An Efficient Inoculation Method for Colonization of Chinese Cabbage Seedlings by the Root Endophytic Fungus Heteroconium chaetospira

To develop an efficient method to inoculate Chinese cabbage seedlings with the root endophytic fungus Heteroconium chaetospira, an appropriate nursery soil and glucose concentration for the nutrient medium for fungal colonization were determined. A grid-sheet method was established for estimating the degree of colonization of entire roots by the fungus. The fungus colonized at high frequencies when peat moss was used as the rooting medium. Colonization was highest (75%) when peat moss was amended with 0.1% glucose. Under these conditions, fungal hyphae developed intracellularly in root cortical cells. In contrast, under high glucose conditions, fungal colonization was restricted mostly to intercellular regions of epidermal or cortical root tissues. Here, hyphae formed inter- or intracellular microsclerotia. Received 19 August 2002/ Accepted in revised form 5 December 2002     

Prevalence and source of trypanosome infections in field-captured vector flies (Glossina pallidipes) in southeastern Zambia

The prevalence of trypanosome infections in tsetse flies, Glossina pallidipes, collected from Chiawa and Chakwenga in Zambia with endemic trypanosomosis was assessed by polymerase chain reaction (PCR). Out of the 550 G. pallidipes, 58 (10.5%) flies were found to harbor trypanosome DNA. Infection rates of tsetse with Trypanosoma vivax universal, Trypanosoma congolense savannah, T. congolense forest and T. congolense kilifi were 4.2% (23/550), 4.7% (26/550), 1.1% (6/550) and 1.6% (9/550), respectively. To determine the mammalian hosts of T. congolense and T. vivax infections from the tsetse flies, mammalian mitochondrion DNA of blood meal in these flies were analyzed by PCR and subsequent gene sequence analysis of the amplicons. Sequence analysis showed the presence of cytochrome b gene (cyt b) of 7 different mammalian species such as human, elephant, buffalo, goat, warthog, greater kudu and cattle. Goats which were main livestock in these areas were further examined to know the extent of its contribution in spreading the infection. We examined the prevalence of trypanosome infections in the domestic goat population in 6 settlements in Chiawa alone. Of the 86 goats sampled, 4 (4.6%), 5 (5.8%), 4 (4.6%) and 4 (4.6%) were positive for T. vivax universal, T. congolense savannah, forest and kilifi, respectively. These findings showed that the host-source of trypanosome infections in vector fly give a vital information about spread of infection. The result of this study will certainly contribute in elucidating more the epidemiology of trypanosomosis.     

Novel variations and loss of heterozygosity of BRCA2 identified in a dog with mammary tumors

OBJECTIVE: To establish novel polymorphic markers for analysis of loss of heterozygosity (LOH), so as to study the possible involvement of BRCA2 in mammary tumors obtained from dogs. SAMPLE POPULATION: Blood samples, mammary gland specimens, or mammary tumors from 3 tumor-bearing dogs and 10 tumor-free dogs. PROCEDURES: Nucleotide sequence analysis was performed with a DNA autosequencer. Loss of heterozygosity analysis was performed for markers established in the present study. The expression level of canine BRCA2 was quantified by real-time PCR analysis. RESULTS: 3 novel microsatellite markers with high heterozygosity rates (> 50%) were established, and the previously reported marker for canine BRCA2 gene locus was improved. These markers were used for the analysis of DNA from formalin-fixed and paraffin-embedded samples. By use of these markers, LOH in canine BRCA2 was identified as a result of recombination. In mammary tumor DNA that corresponded to the LOH-positive dog, the level of canine BRCA2 expression was decreased compared with that of nonneoplastic mammary gland tissue; the open reading frame contained 4 missense variations, 1 insertion variation, and 1 silent variation, some of which were localized to functional domains. CONCLUSIONS AND CLINICAL RELEVANCE: 3 novel polymorphic markers were developed for LOH analysis of canine BRCA2 and identified a dog with LOH with some variations in the functional domains. These markers could be useful for assessing the relevance of BRCA2 variation in mammary tumors of dogs.     

Equine coronavirus induces apoptosis in cultured cells

Equine coronavirus (ECoV) was first isolated from a diarrheic foal and was found genetically similar to group II coronaviruses. However, its pathological characteristics were not adequately investigated. In our preliminary in vitro investigation, ECoV-induced cell death was observed in bovine kidney-derived MDBK cells. Based on this finding, we investigated whether the ECoV-induced CPE was apoptosis. Following ECoV infection, MDBK cells showed morphological changes such as cell rounding and detachment from the culture surface. Moreover, syncytium formation was observed as the other type of cytopathic effect in ECoV infection. Morphologic and biochemical features of apoptosis, such as nuclear fragmentation and DNA ladder formation, were also detected in ECoV-infected cells. Moreover, as is commonly observed in coronavirus infection in other animals, the activities of effecter caspases – caspase-3/7 – and initiator caspases – caspase-8 and caspase-9 – that are representative factors in the death receptor-mediated apoptotic pathway and mitochondrial apoptotic pathway, respectively, were increased in ECoV-infected MDBK cells. Therefore, it was suggested that ECoV can induce apoptosis in MDBK cells via a caspase-dependent pathway. Apoptotic death of infected cells is detrimental because it causes cell and tissue destruction and inflammatory responses. Although the pathological characteristics of ECoV are largely unknown, apoptosis may be the pathological basis of lesions of the digestive system in ECoV infection.     

Role of the α subunit of nicotonic acetylcholine receptor in the selective action of imidacloprid

Examination of agonist interactions of imidacloprid on recombinant chicken α4β2 and Drosophila SAD/Chicken β2 hybrid receptors, expressed in Xenopus oocytes by nuclear injection of the cDNAs, indicates that imidacloprid is a partial agonist. Replacement of the α4 subunit for the Drosophila SAD subunit lowered the imidacloprid EC₅₀ 37-fold, whereas EC₅₀s for other agonists increased 4-50 fold, suggesting that the α subunit contributes to the high affinity of insect nicotonic receptors for imidacloprid. ©1999 Society of Chemical Industry     

An intrinsic mechanism for the co-existence of different survival strategies within mobile pastoralist communities

In mobile pastoralism, strategies of mobility are highly heterogeneous within communities; some herders are frequently mobile and others are not. Moreover, pastoral mobility changes over time, especially after external intervention. Although changes in the strategies of herders affect and are affected by other herders, the interactions between herders with different strategies and the effect of changes in the external environment on their strategies have not been explicitly studied. We examined such interactions with a multi-agent model, simulating the herders’ basic decision-making process, simplified rangeland ecosystem, and animal survival. The results showed clear co-existence of wealthy and poor herders at an intermediate cost of moving. The movement pattern revealed that an indirect interaction between wealthy and poor herders was the key to their co-existence, suggesting that very simple rules of pastoral mobility inherently contain a mechanism for the co-existence of wealthy and poor herders. At an intermediate cost of moving, the two groups have access to different pastures, thus reducing direct competition for poor herders and enabling their survival in drought years. Such interaction between herders suggests that any interventions in mobile pastoralist societies should take into account that impacts on the mobility of any one group can influence the entire social structure.     

Agent-based modeling of complex social–ecological feedback loops to assess multi-dimensional trade-offs in dryland ecosystem services

Context

Recent conceptual developments in ecosystem services research have revealed the need to elucidate the complex and unintended relationships between humans and the environment if we are to better understand and manage ecosystem services in practice.

Objectives

This study aimed to develop a model that spatially represents a complex human–environment (H–E) system consisting of heterogeneous social–ecological components and feedback mechanisms at multiple scales, in order to assess multi-dimensional (spatial, temporal, and social) trade-offs in ecosystem services.

Methods

We constructed an agent-based model and empirically calibrated it for a semi-arid region in Northeast China, and examined ecosystem service trade-offs derived from the Sloping Land Conversion Program (SLCP), which is based on payment for ecosystem services. This paper describes our model, named Inner Mongolia Land Use Dynamic Simulator (IM-LUDAS), using the overview, design concepts, and details + decision (ODD + D) protocol and demonstrates the capabilities of IM-LUDAS through simulations.

Results

IM-LUDAS represented typical characteristics of complex H–E systems, such as secondary and cross-scale feedback loops, time lags, and threshold change, revealing the following results: tree plantations expanded by the SLCP facilitated vegetation and soil restoration and household change toward off-farm livelihoods, as expected by the government; conversely, the program caused further land degradation outside the implementation plots; moreover, the livelihood changes were not large enough to compensate for income deterioration by policy-induced reduction in cropland.

Conclusions

IM-LUDAS proved itself to be an advanced empirical model that can recreate essential features of complex H–E systems and assess multi-dimensional trade-offs in ecosystem services.