The role of copepods (Cyclops spp.) in eliminating the actinospore stages of fish-parasitic myxozoans

The actinospore consumption of copepods (Cyclops spp.) was demonstrated by laboratory observations. It was observed that in experimental dishes the number of actinospores floating in the water decreased, or such actinospores were completely eliminated, in the presence of copepods. The ingestion of actinospores by copepods and their further fate were monitored by fluorescent staining and by conventional histological techniques. The actinospores were observed to have got caught on the filters of Cyclops spp. Two and a half hours after the copepods had been placed into water containing actinospores, their digestive tract was found to contain spores that had extruded their filaments from the polar capsules. After copepods having ingested the actinospores of the species Myxobolus pseudodispar had been fed to roaches, no muscle infection developed in the fish host. It is likely that Cyclops spp. can filter out actinospores floating in the water also from natural waters, thus decreasing the chance of development of myxosporean infections.     

Changes in the regulation and activity of glutathione redox system,and lipid peroxidation processes in short‐term aflatoxin B1 exposure in liver of laying hens

The purpose of this study was to investigate the short‐term (48 hr) effects of feeding aflatoxin contaminated diet (170.3 μg/kg AFB1) in 49‐week‐old laying hens. Liver samples were taken at 12‐hr intervals. Feed intake, body weight, absolute and relative liver weight were the same in groups. However, there was no feed intake during both dark periods (between 12nd to 24th and 36th to 48th hours of the experiment); therefore, aflatoxin intake was also negligible. Markers of initial phase of lipid peroxidation, conjugated dienes and trienes did not change as effect of aflatoxin, but terminal marker, malondialdehyde content was significantly higher at 12 hr as effect of aflatoxin. No significant difference was found in reduced glutathione concentration and glutathione peroxidase activity between the groups. Expression of glutathione peroxidase 4 gene (GPX4) was significantly reduced due to aflatoxin treatment at 12 and 24 hr, but induced later, while glutathione reductase gene (GSR) expression was significantly lower at 24 hr and glutathione synthetase gene (GSS) in aflatoxin‐treated group at 12 hr. The results suggest that aflatoxin induced oxygen‐free radical formation, but it did not reach critical level during this short period of time to cause activation of the expression of glutathione system.     

Magnetic resonance imaging technique for the examination of canine mammary tumours

The aim of this study was to adapt the human magnetic resonance imaging (MRI) sequences for use in the routine examination of canine mammary glands. MRI was performed on 10, middle- to old-aged dogs of different breeds. It was found that T1- and T2-weighted spin echo, short T1 inversion recovery sequences and a gradient echo (GE) dynamic T1-weighted measurement made in the coronal and transversal planes were the most informative MR diagnostic methods for imaging canine mammary tumours. The static MR technique is the most detailed imaging modality for differentiating the tissue types in the substance of the mammary gland. The MRI findings were in close relationship with the histological result (five malignant mixed tumours and five cases of invasive ductal carcinoma). Using the GE dynamic contrast-enhanced sequence the morphological patterns as well as the kinetic parameters proved to be malignant. By the dynamic measurement technique initial information was obtained on the contrast enhancing properties, which are valuable factors during in vivo staging and in the prognostic work.     

Epidemiology of Salmonella derby strains isolated from swine, pork and pork products

A total of 35 Salmonella derby strains, isolated from 6 types of samples of porcine origin from 9 different places in Hungary were examined for their characteristics. Thirty-two strains (91%) were of phage type 25, 2 (6%) of phage type 15 and 1 (3%) of phage type 58. Colicin production was observed in 3 (9%) strains. Five strains (14%) were found to be resistant to tetracycline (Tc). The strains harboured plasmids of 2.2, 2.4, 3.4, 4.2 and 72 Md. The 72 Md plasmid appears to be characteristic of S. derby and possibly encodes Tc resistance. The 72 Md plasmid belonged partly to incompatibility (Inc) group I1, while the other plasmid of the same size belonged to Inc. group B. The findings suggest that healthy salmonella carrier pigs carried the infection from the farm to the abattoir. Slaughtering of infected pigs may have led to contamination of the carcasses and, thereafter, that of the pork and pork products.     

Pre-symptomatic detection of <Emphasis Type="Italic">Plasmopara viticola</Emphasis> infection in grapevine leaves using chlorophyll fluorescence imaging

Plasmopara viticola is an economically important pathogen of grapevine. Early detection of P. viticola infection can lead to improved fungicide treatment. Our study aimed to determine whether chlorophyll fluorescence (Chl-F) imaging can be used to reveal early stages of P. viticola infection under conditions similar to those occurring in commercial vineyards. Maximum (F_V/F_M) and effective quantum yield of photosystem II (Φ_PSII) were identified as the most sensitive reporters of the infection. Heterogeneous distribution of F_V/F_M and Φ_PSII in artificially inoculated leaves was associated with the presence of the developing mycelium 3 days before the occurrence of visible symptoms and 5 days before the release of spores. Significant changes of F_V/F_M and Φ_PSII were spatially coincident with localised spots of inoculation across the leaf lamina. Reduction of F_V/F_M was restricted to the leaf area that later yielded sporulation, while the area with significantly lower Φ_PSII was larger and probably reflected the leaf parts in which photosynthesis was impaired. Our results indicate that Chl-F can be used for the early detection of P. viticola infection. Because P. viticola does not expand systemically in the host tissues and the effects of infection are localised, Chl-F imaging at high resolution is necessary to reveal the disease in the field.     

宁夏气候变化及其对马铃薯生产的影响

简要介绍宁夏回族自治区马铃薯生产分布现状;根据宁夏1961-2000年40年的气候变化,重点分析马铃薯相对气象产量与不同气候因子的相关关系。利用5年滑动平均法分析宁夏和宁南山区年平均温度和降水的变化趋势,并根据1971—2000年30年的马铃薯产量数据进行三次多项式趋势产量拟合,计算气象产量和相对气象产量,利用SPSS统计软件进行马铃薯相对气象产量与不同生育阶段气候因子的相关性分析,以及生长期内不同时段气候参数与相对气候产量的相关性分析。研究结果表明：近40年来,宁夏以及宁南山区的年平均温度呈升高趋势,降水呈下降趋势。发芽期气温日较差的影响比其他气候因子的影响大;幼苗期影响最大的是降水量;发棵期降水量和平均气温的影响相对较大。生育期内不同旬内气候因子对马铃薯生产的影响也是不同的：4月下旬的日照时数（P〈0.01）和7月下旬的旬气温日较差（P〈0.01）对马铃薯生产的影响最大;5月下旬的最低气温（P〈0.05）、7月上旬的平均气温（P〈0.05）和7月下旬的最低气温（P〈0.05）对马铃薯生产的影响次之;其他时段气候因子的影响相对较小。过去40年宁夏的气候正在向暖干的趋势变化,不同的生育阶段,对马铃薯产量影响的气候因子不同,生育内不同旬内气候因子对马铃薯生产的影响也是不同的,已有的气候变化已对马铃薯生产产生不利影响。如果气候暖干的趋势继续,气候变化对马铃薯生产的不利影响也将继续。因此,要采取调整播期等适应措施应对气候变化的不利影响。     

Porcine circovirus type 2 and associated diseases in Romania--short communication

Porcine circovirus type 2 (PCV2) has been demonstrated to be the causal agent for postweaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS). This report describes the first detection of PCV2 and associated diseases in a Romanian swine herd located in Transylvania. The clinical signs, pathological and histopathological changes observed in affected pigs were similar to those previously described for PDNS and PMWS. Polymerase chain reaction and in situ hybridisation were used for the detection of PCV2 nucleic acids from tissues and serum samples. Complete PCV2 genomes of both PMWS and PDNS cases were sequenced and analysed, and by comparing them with each other no genomic differences could be detected. The sequence analysis showed that the Romanian PCV2 was closely related to PCV2 identified in France and in Hungary.     

Tracking of the hormonally induced maturation of female eels by computed tomography

Female European eels were kept in artificial seawater for a trial period of 14 weeks. Three fish were injected intra-abdominally with carp pituitary suspension (twice a week) and human chorionic gonadotropin (every 2nd week), with the aim to induce artificial maturation. Three further fish were not treated (control). Fish were not fed during the trial. The treated fish were scanned by computed tomography (CT) every second week (the controls only at the start and at the end of the trial) to follow changes in body composition. Notable decreases were shown in total body pixel number (body volume), total body fat content, total fillet volume and fillet fat content during the experiment. Changes were more pronounced in the treated group than in the control. The abdominal volume strongly increased in the responding fish throughout the trial. The ovary volume increased measurably, while its fat content increased only until the 8th week, after which a decrease was measured. Tissue volumetric estimations of the ovary were also supported by histological results. A so-called volumetric gonadosomatic index (gonad volume/total body volume x 100) was developed for the quantitative characterisation of eel maturation.     

Soybean: feed quality and safety. Part 1: biologically active components. A review

A large number of soybean components have diverse biological activities. These include hormonal, immunological, bacteriological and digestive effects. The presently known allergens are listed. The divergence between chemical evaluation and biological value is highlighted. The following components are discussed: Kunitz inhibitor, Bowman-Birk inhibitor, saponins, soyacystatin, phytoestrogens (daidzein, glycitein, genistein), Maillard products, soybean hydrophobic protein, soy allergens, lecithin allergens, raffinose, stachyose, 2-pentyl pyridine. The studies describing the effects of the isolated components are reviewed.