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  • Author: Yang Yang x
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Expression of vascular cell adhesion molecule 1 (VCAM-1) in the mammary lymph nodes of cows with subclinical mastitis

Abstract

Introduction: Vascular cell adhesion molecule 1 (VCAM-1) is a member of Ig superfamily. The aim of this study was to prepare highly specific polyclonal antibodies against bovine VCAM-1 and to evaluate the expression of VCAM-1 in the mammary lymph nodes of cows with subclinical mastitis.

Material and Methods: The VCAM-1 gene was cloned from bovine Peyer’s patches and inserted into the pGEX-4T-1 and pET-28a vectors. The recombinant plasmids pGEX-4T-1/VCAM-1 and pET-28a/VCAM-1 were transferred into Escherichia coli BL21 and the recombinant strains were induced by isopropyl-D-thiogalactoside to produce fusion proteins tagged with polyhistidine (His) and glutathione S-transferase (GST), respectively. The expressed fusion proteins His-VCAM-1 and GST-VCAM-1 were identified by SDS-PAGE and Western blot. His-VCAM-1 protein was used as an antigen to immunise Wistar rats and polyclonal antibody serum against VCAM-1 was obtained.

Results: The serum titre tested by indirect ELISA was 128,000 using GST-VCAM-1 as the well coating antigen. Western blots indicated that the antibody recognised recombinant VCAM-1 protein as well as endogenous VCAM-1. In addition, using qPCR and Western blot, VCAM-1 mRNA and protein expression levels were measured in dairy cows with subclinical mastitis. It was demonstrated that VCAM-1 levels in the mammary lymph nodes of the cows were significantly higher than those from healthy controls (P < 0.05).

Conclusion: These results are to our knowledge the first report that VCAM-1 expression in the mammary lymph nodes is elevated in dairy cows with subclinical mastitis.

Open access
Exogenous isoleucine and phenylalanine interact with abscisic acid-mediated anthocyanin accumulation in grape

Abstract

Berry skin colour is a crucial determinant of red/black grape berry quality. We investigated the effects of combination treatments with amino acids and a low concentration of ABA on anthocyanin accumulation in grapes. Among the amino acids tested, isoleucine and phenylalanine resulted in high anthocyanin contents in grape cell cultures. The combination treatments with isoleucine or phenylalanine, and a low concentration of ABA enhanced anthocyanin accumulation in grape cells and detached grape berries. The combination treatment with isoleucine, but not with phenylalanine, and ABA upregulated MybA1 expression. Field-grown grapevines received combination treatments with isoleucine or phenylalanine, and ABA in two growing seasons. In the 2015 growing season, the combination treatments with isoleucine or phenylalanine, and a low concentration of ABA accelerated anthocyanin accumulation in grape berry skins of field-grown grapevines on days 10 and 31 post treatment. The effects on anthocyanin accumulation became negligible at harvest. The effect of the combination treatment with phenylalanine and a low concentration of ABA on anthocyanin accumulation was masked in the 2017 growing season due to the unexpected stimulation of anthocyanin accumulation by the low concentration of ABA, although the combination treatment accelerated anthocyanin accumulation on days 3 and 10 post treatment. Taken together, the results suggested that exogenous isoleucine and phenylalanine interacted with ABA-mediated anthocyanin accumulation in grape berry skins of field-grown grapevines when the activity of ABA used to treat the grapevines was inadequate.

Open access
A sufficient condition for the existence of a k-factor excluding a given r-factor

Abstract

Let G be a graph, and let k, r be nonnegative integers with k ≥ 2. A k-factor of G is a spanning subgraph F of G such that dF(x) = k for each xV (G), where dF(x) denotes the degree of x in F. For SV (G), NG(S) = ∪xS NG(x). The binding number of G is defined by bind (G)=min{|NG(S)||S|:SV(G),NG(S)V(G)}. In this paper, we obtain a binding number and neighborhood condition for a graph to have a k-factor excluding a given r-factor. This result is an extension of the previous results.

Open access
Seasonal population dynamics of the monogeneans Pseudorhabdosynochus coioidesis and P. serrani on wild versus cultured groupers in Daya Bay, South China Sea

Abstract

In this paper, seasonal samples of wild versus cultured groupers, Epinephelus spp., from Daya Bay, South China Sea were examined to survey the seasonality of two important species, Pseudorhabdosynochus coioidesis and P. serrani (Monogenea: Diplectanidae), and to analyze the interspecific relationships between these two parasites. Between April 2008 and January 2009, P. coioidesis and P. serrani were found to be parasitic only on E. coioides Hamilton during summer and winter in the natural waters of Daya Bay, exhibiting a high degree of host specificity, whereas they co-occurred and persisted on several species of hosts, such as E. coioides, E. bruneus Block and E. awoara Temminck & Schlegel, in an experimental polyculture pond during several seasons. E. coioides is the main host for both of these two monogenean species. The overall prevalences and mean intensities of these two parasites on polycultured Epinephelus spp. showed the same pattern of seasonal fluctuations, with the maximum values during autumn, except for the overall prevalence of P. serrani, which reached its maximum values during summer and winter and the minimum values during spring and autumn. Prevalence and mean intensity were found to be related to host size. In the wild, medium-sized fishes harboured higher infections, whereas under cultured conditions the small-sized and large-sized fishes were more heavily infected. Simultaneous infections of P. coioidesis and P. serrani were common, and there was a significant positive interspecific correlation between these two parasites.

Open access
Development and application of a TaqMan-MGB real-time RT-PCR assay for the detection of porcine epidemic diarrhoea virus strains in China

Abstract

Introduction: A real-time RT-PCR method for identification and quantification of porcine epidemic diarrhoea virus (PEDV) strains in China was developed.

Material and Methods: Based on the conserved sequence of the PEDV nucleocapsid (N) gene, a primer pair and probe were designed to establish a TaqMan-MGB real-time RT-PCR assay for quantitative detection of the virus. The sequence was cloned into the pMD18-T vector and a series of diluted recombinant plasmids were used to generate a standard curve with an R2 value of 0.999.

Results: The developed quantitative PCR assay detected viral titres as low as 0.1 TCID50 with high specificity and no cross-reaction with other porcine viruses (PoRV, TGEV, PRRSV, or CSFV). The intra-batch and inter-batch coefficients of variation were both less than 1%, which indicated good reproducibility. Thirty clinical diarrhoea samples obtained from pigs in Shanghai and Fujian were analysed using this quantitative PCR assay. Out of these samples, 93.3% were found to be PEDV positive.

Conclusion: This approach is suitable for clinical sample identification and pathogenesis studies.

Open access
Nutritional Effect of Alpha-Linolenic Acid on Honey Bee Colony Development (Apis Mellifera L.)

Abstract

Alpha-linolenic acid (ALA), which is an n-3 polyunsaturated fatty acid (PUFA), influences honey bee feed intake and longevity. The objective of this study was to research the effect of six dietary ALA levels on the growth and development of Apis mellifera ligustica colonies. In the early spring, a total of 36 honey bee colonies of equal size and queen quality were randomly allocated into 6 groups. The six groups of honey bees were fed a basal diet with supplementation of ALA levels at 0 (group A), 2 (group B), 4 (group C), 6 (group D), 8 (group E), and 10% (group F). In this study, there were significant effects of pollen substitute ALA levels on the feeding amounts of the bee colony, colony population, sealed brood amount, and weight of newly emerged workers (P<0.05). The workers’ midgut Lipase (LPS) activity of group C was significantly lower than that of the other groups (P<0.01). The worker bees in groups B, C, and D had significantly longer lifespans than those in the other groups (P<0.05). However, when the diets had ALA concentrations of more than 6%, the mortality of the honey bees increased (P<0.01). These results indicate that ALA levels of 2 ~ 4% of the pollen substitute were optimal for maintaining the highest reproductive performance and the digestion and absorption of fatty acids in honey bees during the period of spring multiplication. Additionally, ALA levels of 2 ~ 6% of the pollen substitute, improved worker bee longevity.

Open access
Influence of environmental and spatial factors on the distribution of surface sediment diatoms in Chaohu Lake, southeast China

Abstract

- The spatial distribution of surface sediment diatoms in Chaohu Lake (southeast China), and their relationships with environmental and spatial variables were analyzed in this study. The diatom assemblages were dominated by planktonic species. Three dominant species Cyclostephanos dubius, Aulacoseira granulata and Aulacoseira alpigena are unevenly distributed across the lake. The distribution of surface sediment diatoms must be subject to trophic status, hydrodynamics and other spatial variables in the lake.

Open access
Effects of ketosis in dairy cows on blood biochemical parameters, milk yield and composition, and digestive capacity

Abstract

Introduction

This study aimed to characterise the effects of ketosis on milk yield and composition and digestive capacity in transition dairy cows.

Material and Methods

Seven ketotic and seven healthy cows were housed in individual stalls for six days. Samples of plasma, milk, refused total mixed ration, and faeces were collected, and the blood biochemical parameters, milk yield and composition, dry matter intake, and faecal dry matter (FDM) production were determined.

Results

Compared with healthy cows, the ketotic cows had significantly higher concentrations of milk fat and citrate, but lower levels of milk protein and lactose. The cows exhibited a need for acid detergent fibre in forage and better digestion of neutral detergent fibre, starch, crude protein, and phosphorus than healthy cows, but more fat and gross energy were excreted in their faeces. Ketotic cows had higher energy-corrected milk yields and lower FDM than healthy cows.

Conclusion

Lower feed intake coinciding with the requirement to maintain high milk production is considered to be the cause of ketosis in dairy cows. Ketotic cows exhibited lower dry matter fat digestion.

Open access
Test research on the resistance performance of high-speed trimaran planing hull

ABSTRACT

In order to identify high-speed navigation ability of trimaran planing hull, as well as investigate the characteristics of its resistance and hull form, ship model tests were conducted to measure resistance, trim and heaving under different displacements and gravity centre locations. The test results were then used to study the influence of spray strips on resistance and sea-keeping qualities. Moreover, different planing surfaces were compared in the model tests which helped to look into influence of steps on hull resistance and its moving position. Also, the resistance features of monohull and trimaran planing hulls, both with and without steps, were compared to each other. From the tests it can be concluded that: the two auxiliary side hulls increase aerodynamic lift at high-speed motion, which improves the hydrodynamic performance; the trimaran planing hull has also excellent longitudinal stability and low wave-making action; when Fr∇ > 8, its motion is still stable and two distinct resistance peaks and two changes of sailing state (the second change is smaller) appear; spray strips are favourable for sea-keeping qualities at high speed. The change trends before the second resistance peak as to the resistance and sailing behaviour of trimaran planing hull without steps are the same as for monohull planing hull without steps. but when steps in both hulls exist the change trends are different; more specifically: trimaran planing hull with steps has only one resistance peak and its resistance increases along with its speed increasing, and the resistance is improved at the increasing speed as the number of steps increases.

Open access
Fatigue Life Prediction of Umbilicals Considering Non-Linear Stress

Abstract

The fatigue problem induced by wave loads and floater movements of dynamic umbilicals in deepwater is studied. The prediction method of the fatigue life is investigated by considering no-linear local stress due to contact and friction between components of the umbilical. A case study of a dynamic umbilical for 1500 meters depth in South China Sea was presented. The results showed that the more accurate result of the fatigue life was calculated by considering non-linear local stress. The fatigue life by considering local stress with the no-slip assumption was conservative. An obviously longer fatigue life was obtained by considering local stress with the full-slip assumption.

Open access