Persistency and monosaccharide composition of polysaccharides of soil which received no plant materials for a certain period under field conditions

Abstract

The monosaccharides in acid hydrolysates were monitored in soil which was packed in a bag made of glass microfiber paper and buried in upland and paddy fields for up to 36 months. During the initial flush of decomposition, all constituent monosaccharides except for non cellulosic glucose were found to decrease. The amounts which disappeared were greater than the water extractable saccharides of the air dried soil or ground sample of the air dried soil. After the flush of decomposition, the changes in mannose, galactose, fucose and rhamnose were small, whereas cellulosic glucose, arabinose and xylose continued to decline in the upland field soil. The soil saccharides are classified into six groups and their relative persistency is discussed.

The monosaccharide composition did not change markedly, but the proportion of monosaccharides relating to plant materials declined with time after incubation. The molar ratios of hexoses to pentoses, deoxyhexoses to pentoses, and non-cellulosic glucose to cellulosic glucose increased gradually, whereas a gradual decline in the ratio of xylose to mannose was observed when the soil received no plant materials under field conditions.     

Effects of the shoot-cutting method on field propagation in napiergrass (<Emphasis Type="Italic">Pennisetum purpureum</Emphasis> Schum.)

In this study, the effects of shoot-cutting method on propagation using overwintering napiergrass (Pennisetum purpureum Schum.) buds were examined under soil conditions compared with plant growth regulators (PGRs) that are used as an effective method for increasing adventitious buds of several gramineous crops. To increase adventitious budding, we cut shoots of napiergrass at 2 weeks after planting and treated with the following four types of PGR in comparison with shoot-cutting: 4.44 mM BA as cytokinin, 3.63 mM triazine as anticytokinin, 5.37 mM NAA as auxin, and 2.22 mM TIBA as antiauxin, either by injection or direct spraying onto the buds. A large number of adventitious buds were observed in BA- and TIBA-injected buds at 4 WAT compared to shoot-cut or PGR-sprayed buds. However, an extremely low survival rate for tiller-divided plants (nursery plants) derived from both BA- and TIBA-injected plants was observed compared with non-PGR controls. Similar trends on the survival rate and relative tiller number in main shoot-cut plants derived from intact buds (without PGR treatment) were also observed in a repeat trial. The present study demonstrated that the method of shoot-cutting could contribute to increasing propagation efficiency for nursery plants compared with exogenous PGR application, and would be a practical method for increased nursery propagation of napiergrass under soil conditions.     

Two-week Toxicity of Multi-walled Carbon Nanotubes by Whole-body Inhalation Exposure in Rats

To evaluate pulmonary toxicity of multi-walled carbon nanotubes (MWCNTs), F344 rats of both sexes were exposed by inhalation to 0.2, 1 or 5 mg/m³ MWCNT aerosol for 6 h/day, 5 days/week for 2 weeks using a whole-body exposure system. At the end of the 2-week exposure period, one-half of the rats were necropsied, and at the end of an additional 4-week postexposure period, the remaining rats were necropsied. MWCNTs were deposited in the lungs of all MWCNT-exposed groups and mostly remained in the lungs throughout the 4-week postexposure period. Granulomatous changes in the lung were found in the rats exposed to 5 mg/m³ MWCNTs, and these changes were slightly aggravated at the end of the 4-week postexposure period. In the bronchoalveolar lavage fluid (BALF), the numbers of neutrophils, percentages of bi- and multinucleated alveolar macrophages, levels of ALP activity and concentrations of total protein and albumin were elevated in the rats exposed to 1 and 5 mg/m³ MWCNTs. At the end of the 4-week postexposure period, the values of the BALF parameters tended to remain elevated. In addition, goblet cell hyperplasias in the nasal cavity and nasopharynx were observed in the rats exposed to 1 and 5 mg/m³ MWCNTs, but these lesions had largely regressed by the end of the postexposure period. Based on the histopathological and inflammatory changes, the no-observed-adverse-effect level (NOAEL) for inhalation of MWCNTs for 2 weeks was 0.2 mg/m³.     

A simple preparation of betulinic acid from sycamore bark

Betulinic acid is a biologically active compound, which has been well-known for anti-cancerous properties especially for skin. Recently, it has been drawn attention as a compound for combating AIDS. It can be chemically derived from betulin or by solvent extraction from bark. However, bark extracts are complex mixtures that always contain compounds with a wide spectrum of polarity. In this study, we have found a simple method to get high purity betulinic acid from Sycamore outer bark using hot water pre-treatment followed by hydrophilic organic solvent extraction with a yield of 5–6% (w/w).     

Insecticidal activity and nicotinic acetylcholine receptor binding of dinotefuran and its analogues in the housefly, Musca domestica

The insecticidal activity of dinotefuran and 23 related compounds against the housefly, Musca domestica (L) was measured by injection with metabolic inhibitors. Dinotefuran was less active than imidacloprid and clothianidin by a factor of 10 in molar concentrations. Their binding activities to the fly-head membrane preparation were measured by using [125I]alpha-bungarotoxin ([125I]alpha-BGTX) and [3H]imidacloprid ([3H]IMI) as radioligands. The activity of some selected compounds measured with [3H]IMI was 10(4)-fold higher than that measured with [125I]alpha-BGTX. With [3H]IMI as a radioligand, dinotefuran was 13-fold less active than imidacloprid. The inhibitory effect of dinotefuran on the binding of [3H]IMI to the membrane preparation was in a competitive manner. Quantitative analysis of the insecticidal activity of the test compounds with the binding activity measured with [3H]IMI showed that the higher the binding activity, the higher was the insecticidal activity.     

Nicotinic acetylcholine receptor binding of imidacloprid-related diaza compounds with various ring sizes and their insecticidal activity against Musca domestica

Fifteen 5-substituted 1-(6-chloro-3-pyridylmethyl)-2-nitromethylene-1,3- diazacyclohexanes and three other related compounds having a five- or seven-membered ring were synthesized and their biological activities were measured in vivo and in vitro. The insecticidal (in vivo) activity was evaluated against houseflies Musca domestica L under synergistic conditions with propargyl propyl phenyl phosphonate and piperonyl butoxide. The binding activity of each compound to nicotinic acetylcholine receptor in vitro was measured using [125I] alpha-bungarotoxin. The insecticidal activities of the unsubstituted diazacyclohexane analogues were slightly higher than those of the imidazolidine analogues, but the enlargement of ring size to diazacycloheptane lowered the activity. Substitution of 1,3-diazacyclohexane or imidazolidine rings was not generally favourable for the activity, but the unsubstituted 1,3-diazacyclohexane analogue showed the highest binding activity. Ring substitutions and ring enlargement decreased the activity 100-30,000-fold.     

Agent-based model for Johne’s disease dynamics in a dairy herd

Johne’s disease is an infectious gastrointestinal disease in ruminants caused by Mycobacterium avium subsp. paratuberculosis that causes diarrhea, emaciation, decreased milk production and eventually death. The disease is transmitted in utero and via milk and colostrums to calves, and fecal-orally to all age classes. Financial losses due to the disease are estimated to be over $200 million in the US dairy industry. The goal of this study was to evaluate the cost effectiveness of control measures based on diagnosis with a sensitive ELISA, EVELISA. An agent-based, discrete time model was developed to simulate Johne’s disease dynamics in a US dairy herd. Spatial aspects of disease transmission were taken into account by using six spatial compartments. The effects on disease prevalence were studied with and without transmission routes included in the model. Further, using the model, cost effectiveness of ELISA-based Johne’s disease control was evaluated. Using the parameters we collected and assumed, our model showed the initial prevalence of Johne’s disease (33.1 ± 0.2%) in the farm increased to 87.7 ± 1.7% in a 10 year-simulation. When ELISA-based control measures were included in the simulation, the increase in prevalence was significantly slowed down, especially when EVELISA was used. However, the level of the prevalence was still higher than the initial level after 10 year simulation even with the ELISA-based diagnostic intervention. The prevalence was further reduced when quarterly ELISA testing was included. The cost analysis showed that the quarterly ELISA and EVELISA testing could bring $44.8 and $51.5/animal/year more revenues, respectively, to a dairy farm.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-015-0195-y) contains supplementary material, which is available to authorized users.     

An immuno-epidemiological model for Johne’s disease in cattle

To better understand the mechanisms involved in the dynamics of Johne’s disease in dairy cattle, this paper illustrates a novel way to link a within-host model for Mycobacterium avium ssp. paratuberculosis with an epidemiological model. The underlying variable in the within-host model is the time since infection. Two compartments, infected macrophages and T cells, of the within-host model feed into the epidemiological model through the direct transmission rate, disease-induced mortality rate, the vertical transmission rate, and the shedding of MAP into the environment. The epidemiological reproduction number depends on the within-host bacteria load in a complex way, exhibiting multiple peaks. A possible mechanism to account for the switch in shedding patterns of the bacteria in this disease is included in the within-host model, and its effect can be seen in the epidemiological reproduction model.     

The within host dynamics of Mycobacterium avium ssp. paratuberculosis infection in cattle: where time and place matter

Johne’s disease or paratuberculosis, caused by Mycobacterium avium subsp. paratuberculosis (MAP), occurs in domestic and wild animals worldwide, causing a significant economic loss to livestock industries. After a prolonged incubation time, infected cattle shed MAP bacilli into feces and spread the disease to an uninfected animal population. It is largely unknown how (or whether) the interplay between the pathogen and the host immunity determines timing of shedding after the long incubation time. Such information would provide an understanding of pathogenesis in individual animals and the epidemiology of MAP infection in animal populations. In this review, we summarize current knowledge of bovine Johne’s disease pathology, pathogenesis, immunology and genetics. We discuss knowledge gaps that direly need to be addressed to provide a science-based approach to diagnostics and (immuno)prophylaxis. These knowledge gaps are related to anatomical/clinical manifestation of MAP invasion, interaction of bacteria with phagocytes, granuloma formation, shedding, establishment and kinetics of adaptive immune responses in the pathogenesis of the disease. These topics are discussed at the molecular, cellular and tissue levels with special attention to the within host dynamics including the temporal and the spatial context relevant for the various host-pathogen interactions.