基于卷积神经网络的微藻种类识别

微藻在生态系统的结构和功能中具有极为重要的作用,而传统光学人工镜检方法对微藻种类鉴别具有较大的难度。本研究将微藻的光学图像进行了采样,并结合国内外专家对微藻鉴定的经验知识,制作了微藻图像数据集,并进行了数据增强处理。借助深度学习的原理和方法,构建了基于卷积神经网络结构的深度学习模型（AlexNet）,对模型进行了训练,并利用5折交叉验证方法确保模型的稳定性。结果表明,模型的训练精度可达到98.78±0.98%,测试精度达85.46±0.23%,达到了预期效果。利用AlexNet模型训练得到的参数,对预留的280个样本图像进行实际测试,7个藻种的平均精确度、平均召回率和平均F1 Score分别为0.832,0.844和0.833。表明深度学习方法是鉴定微藻的一种有效方法。     

MAGNETIC RESONANCE IMAGING FINDINGS IN THE SPINE OF SIX DOGS DIAGNOSED WITH LYMPHOMA

Lymphoma is one of the most common neoplasms in the dog. Despite its prevalence and the increasing use of advanced diagnostic imaging in veterinary patients only few reports of magnetic resonance imaging (MRI) findings in spinal lymphoma have been published to date. The purpose of this retrospective case series study was to describe the MRI findings in dogs with confirmed lymphoma affecting the spine and/or paraspinal soft tissues. Medical records were searched for patients that had MRI of the spine and a diagnosis of lymphoma during the period of 2005–2015. Data recorded from retrieved MRI studies were presence of focal or multifocal disease, structures involved, and signal characteristics on T2‐W, short tau inversion recovery (STIR), and T1‐W sequences prior to and following intravenous contrast medium administration. Six dogs met the inclusion criteria. Common findings included multifocal disease (4/6), vertebral involvement (5/6), spinal cord compression (4/6), and involvement of more than one spinal compartment (medullary cavity, vertebral canal, paraspinal soft tissues) (6/6). Vertebral changes were confined to the medullary cavity without evidence of cortical osteolysis. There was questionable involvement of the spinal cord in one case. All spinal and paraspinal lesions identified were T2‐W isointense to hyperintense, STIR hyperintense, T1‐W hypointense to isointense, and showed variable moderate to strong contrast enhancement. Additional lesions identified were enlarged intraabdominal lymph nodes, hepatomegaly, splenomegaly, and a splenic nodule. The STIR and T1‐W postcontrast sequences were subjectively the most useful in identification of the spinal and paraspinal lesions.     

GnRH‐agonist deslorelin implant alters the progesterone release pattern during early pregnancy in gilts

The aim of this study was to investigate the relationship of progesterone (P) and luteinizing hormone (LH) during recognition and establishment of pregnancy in the gilt. Therefore, the effects of eliminating episodic LH pulses on P patterns were determined during early pregnancy. To this end, a slow‐release GnRH implant deslorelin was used for GnRH down‐regulation. A group of gilts (GnRHa, n = 8) was implanted with the GnRH‐agonist on Day 11 of pregnancy, while a control group (C, n = 5) was treated with a non‐impregnated placebo implant. Blood was collected via a vena cava caudalis catheter at 10‐min intervals for 8 hr on Day 16 and 21 of pregnancy. As expected, the GnRH implant reduced LH secretion (p < 0.01) and abolished LH pulses completely at Day 16 and Day 21 of pregnancy. On Day 16, there was no difference in P levels between the treatments. However, on Day 21, the GnRH‐agonist treatment led to significantly increased P concentrations (p < 0.01) compared with the control gilts. Progesterone was secreted in a pulsatile manner in both treatment groups and no relationship between LH pulsatility and P pulsatility was observed. In conclusion, abolishment of LH pulsatility did not affect the pulsatile pattern of P secretion but led to an unexpected overall increase in P on Day 21 of pregnancy; this effect was delayed and occurred 10 days after commencing treatment with the GnRH depot agonist. The elevation of P on Day 21 of pregnancy in the GnRHa group suggests either a reduced negative feedback effect or an increased autocrine response by the corpora lutea.     

Health status and potential uptake of transgenic DNA by Japanese quail fed diets containing genetically modified plant ingredients over 10 generations

1. The hypothesis assumes that feed containing GMOs affects animal health and results in the transgene product accumulating in the body. Therefore, the objective of the study was to evaluate the impact of genetically modified (GM) ingredients used in poultry diets on aspects of bird health status and accumulation of transgenic DNA in eggs, breast muscle and internal organs.

2. A total of 10 generations of Japanese quail were fed three types of diets: group A – containing GM soya (Roundup Ready) and non-GM maize, group B – containing GM maize (MON810) and non-GM soya, and group C – containing non-GM soya and maize.

3. Bird performance traits were monitored throughout the trial. In 17-week-old animals of each generation, health examination took place on birds from each group including post-mortem necropsy and histological organ evaluation. For the purpose of transgenic DNA detection, samples of selected important tissues were taken. A molecular screening method of PCR amplification was used.

4. The analysis of the sectional examination of birds used in the current experiment did not indicate the existence of the pathological changes caused by pathogens, nutritional factors or of environmental nature. The histopathological changes occurred in all three dietary groups and there were no statistically significant differences between the groups.

5. There was no transgene amplification – neither CaMV35S promoter sequence nor nos terminator sequence, in the samples derived from breast muscle, selected tissues and germinal discs (eggs).

6. According to the obtained results, it was concluded that there was no negative effect of the use of GM soya or maize with regard to bird health status or to the presence of transgenic DNA in the final consumable product.

     

Differences in the tissue tropism to chicken oviduct epithelial cells between avian coronavirus IBV strains QX and B1648 are not related to the sialic acid binding properties of their spike proteins

The avian coronavirus (AvCoV) infectious bronchitis virus (IBV) is a major poultry pathogen. A characteristic feature of IBV is the occurrence of many different strains belonging to different serotypes, which makes a complete control of the disease by vaccinations a challenging task. Reasons for differences in the tissue tropism and pathogenicity between IBV strains, e.g. a predilection for the kidneys or the oviduct are still an open question. Strains of the QX genotype have been major pathogens in poultry flocks in Asia, Europe and other parts of the world. They are the cause of severe problems with kidney disease and reproductive tract disorders. We analysed infectivity and binding properties of the QX strain and compared them with those of the nephropathogenic strain B1648. As most IBV strains do not infect permanent cell lines and show infection only in primary chicken cells of the target organs, we developed a culture system for chicken oviduct explants. The epithelial cells of the oviduct showed a high susceptibility to infection by the QX strain and were almost resistant to infection by the nephropathogenic B1648 strain. Binding tests with isolated primary oviduct epithelial cells and soluble S1 proteins revealed that S1 proteins of two IBV strains bound with the same efficiency to oviduct epithelial cells. This attachment was sialic acid dependent, indicating that the sugar binding property of IBV spike proteins is not the limiting factor for differences in infection efficiency for the oviduct of the corresponding viruses.     

Site-specific formation of Maillard, oxidation, and condensation products from whey proteins during reaction with lactose

Heat treatment of dairy products leads to structural changes of proteins, which can severely decrease the nutritional value [Mauron, J. J. Nutr. Sci. Vitaminol. (Tokyo) 1990, 36 (Suppl. 1), S57-69]. In this study, model solutions of the two main whey proteins, alpha-lactalbumin and beta-lactoglobulin, respectively, were incubated with lactose, and modifications were monitored by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Lactulosyl residues were the most abundant modifications of alpha-lactalbumin and beta-lactoglobulin. Up to four of these adducts were identified on the proteins. Enzymatical digest with endoproteinase AspN prior to mass spectrometric analysis allowed the detection of further modifications and their localization in the amino acid sequence. Most prominent modifications were lactulosyllysine, Nepsilon-carboxymethyllysine, oxidation of lysine to aminoadipic semialdehyde, oxidation of methionine to methionine sulfoxide, cyclization of N-terminal glutamic acid to a pyrrolidone, and oxidation of cysteine or tryptophan. The presence of methionine oxidation was deduced from a control protein that had been oxidized by hydrogen peroxide. These studies establish MALDI-TOF-MS as a reliable tool to monitor chemical modifications of nutritional proteins during food processing.     

Limitations of faunal effects on soil carbon flow: density dependence, biotic regulation and mutual inhibition

Soil animals are known to stimulate soil microbial activity and thereby to accelerate decomposition of soil organic matter. In this paper, we investigate potential limitations of soil animal effects on soil carbon flow by analysing how animal effects relate to the density of four major faunal groups. Specifically, we analyse the extent to which faunal effects are subject to biotic regulation or to mutual inhibition between groups under different levels of resource supply.In an extensive laboratory experiment, 96 microcosms established in three consecutive blocks were inoculated with nematodes, enchytraeids, microarthropods, and lumbricids. Each faunal group was inoculated in three densities, including combinations of groups. Introduced animal densities were within the natural range of densities in fallow soil. Bare agricultural soil and soil covered with maize litter were used as substrates. The microcosms were kept under constant conditions at 12 °C and 50% water holding capacity for 8 weeks. Soil CO₂ evolution was measured daily by means of gas chromatography.Animal effects were on an average relatively stronger in bare soil (+95% CO₂; R²=0.76) than in soil with litter (+14% CO₂; R²=0.40), where organic matter decomposition was seven times more intense. Higher animal densities generally led to accelerated decomposition up to three times that of the controls. However, beyond a specific density, decomposition rates stopped increasing or even declined, depending on the faunal group. In addition, animal effects were limited by mutual inhibition between groups in bare soil where effects were strong, while stimulatory interactions were prominent in the litter treatments where effects were generally weak.We interpret the limitation of soil faunal effects on soil carbon flow in terms of incomplete habitat exploitation and biotic regulation. Under conditions of substrate homogeneity, such as in the bare soil treatments, animal effects were stronger, but they were limited by overexploitation. Under conditions of substrate heterogeneity, such as in the litter treatments, animal effects were limited by incomplete habitat utilisation. We assume that complementary habitat colonisation by different faunal groups in the litter treatments gave rise to positive diversity effects, but that these effects did not compensate for reduced overall habitat utilisation. We infer that a knowledge of faunal resource utilisation and of mutual inhibition of faunal groups can be exploited for ecological soil management towards stabilisation of soil organic matter.