Adherence of Actinobacillus pleuropneumoniae serotype 1 to swine buccal epithelial cells involves fibronectin

The swine pathogen Actinobacillus pleuropneumoniae serotype 1 was investigated for its ability to adhere to swine, rat, and human buccal epithelial cells (BEC). The highest number of bacteria adhered was to swine BEC. This binding ability was affected by heating, extreme pH, treatment with sodium dodecyl sulfate, ethylenediamine tetraacetate, or periodate, and proteolysis, suggesting that cell-surface glycoproteins participate in adherence and that adherence is based mostly on ionic interactions. Mannose and swine fibronectin may play a direct role in this interaction. Convalescent-phase serum from naturally infected pigs inhibited the adhesion. There was a correlation between bacterial pathogenicity as well as host specificity and the capacity for adherence to swine BEC. Adhesion to swine BEC provides a convenient method to study in vitro the adherence of A. pleuropneumoniae and other pathogens of the pig respiratory tract.     

A comparison of the uterine proteome of mares in oestrus and dioestrus

Proteomic analysis of mare uterine flush fluid provides a minimally invasive technique for studying protein changes associated with the oestrous cycle. The aim of this study was to identify differentially abundant proteins in the uterine flush fluid of mares in oestrus and dioestrus. In this study, uterine flush fluid samples were collected from eight reproductively healthy mares in either oestrus (n = 5) or dioestrus (n = 3). Proteomic analysis was performed using liquid chromatography‐tandem mass spectrometry. Of 172 proteins identified, six proteins (immunoglobulin lambda‐like polypeptide 1, haemoglobin subunit alpha, alpha‐1B‐glycoprotein, serotransferrin, apolipoprotein A‐1, and haemoglobin subunit beta) were significantly more abundant in oestrus. These proteins may contribute to the endometrial defence system through roles in inflammation, immunity or antimicrobial activity. In other species, some of these proteins have been described as immunoglobulins, negative acute phase proteins or defence agents against micro‐organisms. During dioestrus, immunoglobulin alpha‐1 chain C region‐related, complement factor I, CD 109 antigen and uterocalin, were significantly more abundant. Research in other species suggests that these four proteins contribute to the immune response through proposed immunoregulatory characteristics, complement system involvement or roles in B cell–T cell interactions. In conclusion, ten differentially abundant proteins were identified in the uterine flush fluid of mares in oestrus and dioestrus. Targeted studies on these proteins could elucidate their role in uterine defence mechanisms during the oestrous cycle in the mare.     

Chemical Characterization and Release of Polyphenols from Pecan Nut Shell [<Emphasis Type="Italic">Carya illinoinensis</Emphasis> (Wangenh) C. Koch] in Zein Microparticles for Bioactive Applications

The pecan nut [Carya illinoinensis (Wangenh) C. Koch] is a natural source of polyphenols with antioxidant properties. In this study, the encapsulation of aqueous and hydroalcoholic extracts of pecan nut shell were evaluated for the release of bioactive compounds and antioxidant potential in order to explore food applications using zein as encapsulating agent. The extracts showed high contents of total phenolics, condensed tannins and high antioxidant activity. Concentrations of proanthocyanidins were 9-fold higher in hydroalcoholic extracts. The LC-DAD analysis showed that catechins were the major phenolic compounds in samples, with epigallocatechin levels up to 138.62 mg mL^?1. Zein microparticles loaded with aqueous extract released 2.3 times more phenolic compounds than the hydroalcoholic extracts and the DSC thermograms showed that extracts of pecan nut shell remained thermally stable up to 240 °C. The zein microcapsules obtained in this study were efficiently encapsulated and represent an interesting additive due its high antioxidant capacity, physicochemical characteristics and morphology. The use of zein microparticles combined with natural extracts constitute a step forward in the improvement of current technology for delivering phenolic compounds with applications in functional foods and nutraceuticals.     

Inheritance of the stay-green trait in tropical maize

Stay-green maize genotypes have been associated with tolerance to biotic and abiotic stresses, including tolerance to drought, and to stalk and root lodging, but there is limited information on its inheritance. Thus, this research was conducted to study the inheritance of the stay-green trait using both conventional analysis and QTL mapping of the Design III in a tropical maize population developed from two inbred lines genetically divergent for this trait. Two-hundred and fifty F₂ plants were genotyped with 177 microsatellite markers, and their backcrossed progenies to both parental inbreds were evaluated at three locations. Ten plants per plot were assessed 120 days after sowing and the plot means scores for stay-green, adjusted for days to silking emergence, were used for analysis. The additive variance was larger than the dominance variance, the genetic by location interaction variance presented a high magnitude, and the heritability coefficient on a plant-basis a low magnitude. Seventeen QTL were mapped, most of them were clustered on four chromosomes and accounted for by 73.08 % of the genetic variance. About half of the QTL interacted with location, and the average level of dominance was partial dominance. The additive effects were larger than the dominance effects; the latter were not unidirectional, so that heterosis could not be exploited in crosses. Procedures for marker-assisted selection to increase the level of stay-green are discussed and an approach is suggested for using both stable and non-stable QTL in a marker-assisted backcross program.     

Integrated production of fish (pacu <Emphasis Type="Italic">Piaractus mesopotamicus</Emphasis> and red tilapia <Emphasis Type="Italic">Oreochromis</Emphasis> sp.) with two varieties of garnish (scallion and parsley) in aquaponics system

Aquaponics is emerging as an alternative for high-health food production. Being able to identify the technical viability of non-conventional plants and fish species would help to increase the interest and possibilities in aquaponic systems. The goal of the present study was to evaluate the aquaponics production of two garnish species: scallion (S) and parsley (P), using effluents of pacu and red tilapia culture. Two aquaponics devices were used, differing according to the fish species, generating two different effluents. Thus, for plant performance, four treatments were evaluated in a factorial design (plant species and fish effluent as main factors), as followed: Pacu-S, Tilapia-S, Pacu-P, and Tilapia-P, with three replicates each, for 35 days. Fish performance was evaluated using Student’s t test. Each experimental device included a fish tank, filters, and six experimental units for the plants (floating rafts). Results indicated that feed conversion ratio (FCR) was higher in tilapia as compared to pacu (p < 0.05); however, fish productivity and survival were similar between species. Plant performance parameters were similar with no significant differences regardless of the fish effluent (p > 0.05), except for higher number of leaves per plant in scallion cultured using pacu effluent. Plant performance comparing both plant species indicated that scallion performed better as compared to parsley in all parameters. In addition, scallion also performed better related to the plant quality index. The results indicate that pacu presented a viable alternative for the aquaponics production, and regarding to the garnish, scallion performed better results as compared to parsley.     

Effect of mannitol pretreatment to improve green plant regeneration on isolated microspore culture in Triticum turgidum ssp. durum cv. 'Jennah Khetifa'

The use of doubled haploids improves the efficiency of cultivar development in many crops and can be helpful in genetic and molecular studies. The major problem with this approach is the low efficiency of green plant regeneration. We describe here an efficient method for inducing embryos and regenerating green plants directly from isolated microspores of durum wheat cv. ‘Jennah Khetifa’. Tillers from donor plants were pretreated in 0.3 m mannitol and were stored at 4°C at various times: 3, 5, 6, 7, 8, 10 and 12 days. Our results showed clearly that the novel pretreatment combined mannitol 0.3 m and cold for 7 days had a strong effect on the number of embryos produced and regenerated green plants. Under this condition 13 475 mature embryos were produced from 2 693 500 microspores. Moreover, 85 green plants were obtained. High green plants regeneration frequency was recorded. As an average 11.55 green plants were produced per 100 000 microspores (about the equivalent of six plants per spike). Therefore, this study showed clearly that our results are the best ones published until now in durum wheat.     

The Tripartite Symbiosis Formed by Indigenous Arbuscular Mycorrhizal Fungi, Bradyrhizobium japonicum and Soya Bean Under Field Conditions

The tripartite symbiosis formed by indigenous arbuscular mycorrhizal fungi (AMF), Bradyrhizobium japonicum (Kirchner) Jordan and soya bean (Glycine max L. Merr. cv. Evans) was investigated under field conditions to test the hypotheses that: (i) the tripartite symbiosis enhances nodulation and nodule activity; and (ii) its establishment does not rely on improved phosphorus (P) uptake through the fungal partner. Soil tillage was used to produce treatments with contrasting AMF colonization potentials while the amount of B. japonicum inoculum was kept constant. Nodulation, AMF colonization and the P and nitrogen (N) nutrition of plants were evaluated at 10 and 51 (full‐bloom) days after emergence. N₂ fixation was estimated by the difference method and by the isotopic dilution method. At the early stage of plant growth, AMF hyphal colonization and nodulation were, respectively, 16 % and 33 % greater in plants from untilled than from rototilled soil. The establishment of the tripartite symbiosis was observed under field conditions, and factors other than P nutrition were critical to its formation. However, the tripartite symbiosis did not promote N₂ fixation under the high soil P conditions of this study.     

用AFLP技术构建棉花雄性不育三系及其杂种F1的DNA指纹图谱

实验应用AFLP同位素标记法,获得了棉花细胞质雄性不育系、保持系、恢复系及其杂种F1的DNA指纹图谱.较为详尽地介绍了有关AFLP的技术核心及注意点,并探讨了其适用于棉花研究的方法.结果表明,AFLP是一种十分有效的DNA指纹技术,它具有多态性丰富、稳定性高、重复性好等优点.     

水杨酸对暖季型草坪草马尼拉叶片抗氧化酶系的调节作用

研究了水杨酸（salicylic acid,SA）对暖季型草坪草马尼拉（Zoysia motrella）叶片抗氧化酶系活性的调节作用。0.5-5.0mmol/L的SA处理均能显著地提高被处理叶片超氧化物歧化酶（SOD）和过氧化物酶（POD）活性。用1.0mmol/L的SA处理后48h，POD活性比对照增加了76％。但过氧化氢酶（CAT）的活性被抑制.