Skeletal muscle characteristics in young trained and untrained standardbred trotters.

Muscle biopsies were taken from the middle gluteal muscle of 28 Standardbred trotters, 3-4 years of age. The 13 horses in Group T were trained consistently from 18 months of age, whereas the 15 horses in Group UT were not exposed to any systematic training before 3 years of age. Group T horses had a lower percentage of Type IIB fibres (31%) than did Group UT horses (39%). Citrate synthase (CS) activity, representing oxidative capacity, was higher in Group T (72 mmol kg-1 min-1) than in Group UT (47 mmol kg-1 min-1). Biopsies were taken from 4 horses in each group when they were foals and then annually until 3-4 years of age. Results from this study indicate that regular training of Standardbreds from 18 months of age resulted in increased CS activity and a decrease in the percentage of Type IIB fibres. This study shows that training, not growth, is the main factor that induces a high oxidative capacity and a high Type IIA/IIB fibre ratio in muscle of Standardbred trotters.     

Effect of Cultivar Resistance and Haulm Killing Method on Tuber Infection by <Emphasis Type="Italic">Phytophthora infestans</Emphasis>

A series of field trials combining cultivars with different levels of resistance to Phythophtora infestans and different haulm killing methods was conducted in 1997, 1998 and 1999 to assess the contamination potential of the haulm. In addition, the frequency of tubers with late blight was assessed after harvest and storage, combining effects of pretreatment infection, infection by the haulm at harvest and the development of the disease during storage. Haulm killing was performed by diquat (200, 400, 600 g a.i. ha^-1), half cutting of the haulm in combination with diquat (100, 200, 300 g a.i. ha^-1) or full cutting of the haulm. In those treatments where haulm killing was performed purely chemically the haulm remnants’ contamination potential tended to increase at reduced doses. Full mechanical destruction gave as low a contamination potential as application of the full dose of chemical haulm killer. However, there were no consistent differences between the haulm killing treatments in the frequency of blighted tubers after harvest and storage. This indicates that the input of chemical haulm killers may be reduced. There was a large difference between years in tuber blight after harvest and storage, which confirms that climatic factors are of major importance for tuber infection. The large difference found between the cultivars in the frequency of tuber blight indicates that tuber resistance should be an important part of integrated late blight disease management.     

The efficacy of a single intraperitoneal injection of either flumequine or oxytetracycline hydrochloride in prevention of outbreaks of atypical Aeromonas salmonicida infection in goldsinny wrasse, Ctenolabrus rupestris L., following stress.

In this investigation, the efficacy of a single intraperitonealinjection of either flumequine or oxytetracycline hydrochloride to preventoutbreak of atypical Aeromonas salmonicida infection ingoldsinny wrasse, Ctenolabrus rupestris, following stresswas studied. Six groups of goldsinny wrasse, each of 50 individuals, weretreated with an intraperitoneal injection of either propylene glycol : saline(50 : 50), 200 mg kg^–1 of oxytetracycline or 50mg kg^–1 of flumequine dissolved in propyleneglycol : saline (50 : 50). Three days following medication the fish in allgroups were stressed by an intraperitoneal injection of prednisolone acetate(0.05 ml) and a rise in seawater temperature from 9 to 11°C. Mortality was observed daily for 21 days. Flumequine wasthe more effective with a mean cumulative mortality of 5% compared tooxytetracycline with 54%. The mean cumulative mortality in the unmedicatedcontrol groups was 84%. Bacterial examination of kidneys from dead fishconfirmed the presence of atypical A. salmonicida as theprobable cause of death. Minimum inhibitory concentration (MIC) values forflumequine and oxytetracycline against the isolated A.salmonicida were determined to 0.13 gml^–1, and 2.0 g ml^–1,respectively.     

Recruitment of sympatric vendace (Coregonus albula) and whitefish (C. lavaretus) is affected by different environmental factors

Vendace and whitefish in Lake Osensjøen (boreal south‐east Norway) were studied by means of gillnet test fishing (1976–2013) and hydro acoustic acquisition (1986–2011). Vendace increased in number between 1998 and 2009 while growth and size at maturity decreased. The relative density of whitefish decreased in the pelagic habitat, whereas growth and size remained the same. Both species exhibited varying year‐class strength. Whereas strong year‐classes of both species became less frequent after 1980 than before this, this seemed to change after 2000, especially for vendace. Generalised additive models suggested a strong positive relationship between July/August mean air temperature and year‐class strength of both vendace and whitefish. Whitefish recruitment was also negatively affected by the new regulation regime implemented since 1981, and positively correlated with water level after hatching and by late ice off. The reason for the diverging impacts of environmental factors on the two species may be that vendace spawn in deeper waters that whitefish do. The results indicate that increasing summer temperatures benefit recruitment of both species, whereas low water level and early ice off will harm whitefish recruitment. Both trends are caused by climate warming. It may be speculated that increased density of the specialised plankton feeding vendace may affect the algal community through increased predation on herbivorous zooplankton and potentially affect the trophic state of the lake.     

Heavy Metal Pollution in Air-Water-Soil-Plant System of Zhuzhou City,Hunan Province,China

The sources, distribution and mobility of heavy metals in Zhuzhou City, Hunan Province, China were systematically studied based on environmental monitoring data and random sampling from fields and markets. The significant positive correlations between some pairs of heavy metals (total Cd–Hg, total Cu–Pb) within the Zhuzhou section of the Xiang River may indicate that they are coming from the same pollution sources with similar pollution channels and removal patterns in the water bodies. Heavy metals from wastewater partly settled in the sediment after entering the Xiang River, which caused an inconsistent change in heavy metal concentrations over time in the middle and lower parts of the Xiang River. There was no significant difference in total Pb and Zn in topsoil between years in the period 1990–1997, which showed the balance between input and output. Heavy metals accumulated mainly in the topsoil with little downward movement. Heavy metals in the vegetables and rice were higher than the edible standard and background value to some degree with minor exceptions. The maximum heavy metal level observed divided by the acceptable level was in the order of Cd > Pb > Cu > Zn. Significant positive correlations were only found between cabbage uptake and total soil content for Hg, Pb and Cd, with no significant correlationfor the other elements. The plant uptake of a heavy metal was somewhat influenced by the co-existence of other elements.     

Non-abscised aborted sweet cherry fruits are vulnerable to fruit decaying fungi and may be sources of infection for healthy fruits

During three growing seasons (1999–2001), disease incidence of non-abscised aborted and normally developing (sound) sweet cherry fruits were investigated in a research orchard at Ullensvang, western Norway. To reveal possible fungal infections, aborted and sound fruits of two cultivars (cv. Van for three years and cv. Lapins for two years) were harvested over four to seven weeks in an experimental orchard during the green fruit phase and incubated at 20°C in moisture saturated air for 7 days. The most frequently observed fungal pathogens were Monilinia laxa, Colletotrichum gloeosporioides, and Botrytis cinerea. The mean of all observations (±standard deviation) over three years, showed that aborted and sound fruits had a disease incidence of 51.9% (±31.8) and 5.2% (±9.7), respectively, after seven days incubation. In 24 of 25 trials aborted fruits had significantly higher disease incidence than sound fruits after incubation. In one season, when fruits were collected from two commercial orchards, aborted fruits had much higher disease incidence than sound fruits (a mean of 6.5 and 4.5 times higher incidence for the two orchards, respectively). Time of fruit abortion varied with the years (two years observation) and the two cultivars, but the major abortion took place between the fourth and eighth week after anthesis. A higher disease incidence and more rapid disease development in non-abscised aborted fruits indicate that they are more vulnerable to fungal colonisation than sound fruits and may thus be potential incoulum sources for neighbouring, healthy fruits.     

Animal models for human metapneumovirus (HMPV) infections

Since its detection in 2001 the human Metapneumovirus (HMPV), a member of the Paramyxoviridae family, was observed to be a serious pathogen in human respiratory infections during childhood. Meanwhile, several animal models have been established to study the virus-host interactions and pathogenic effects. Mainly, small laboratory animals like mice and cotton rats have been used, although the usage of these two species for HMPV research is controversially discussed and contradictious results were obtained by different groups. Further trials with ferrets, hamsters and non human primates were performed revealing different success in their individual usage. In this review we present the different animal models, summarize their advantages and disadvantages, and discuss the controversial results from different studies.     

Optimizing the lighting regime for Alstroemeria with respect to photoperiod and fluence rates

The Alstroemeria cultivars Diamond, King Cardinal and Libelle were grown for 18 months under five lighting regimes with, and without, soil cooling. The aim was to optimize the daily investment of light energy from artificial sources with respect to photoperiod and photosynthetic fluence rates and to elucidate possible links between reactions to photoperiod and root-zone temperature. The more photons (photosynthetically active radiation, PAR) that were supplied to the plants per day (8, 11 and 13 mol m⁻²), the higher was the total production of flowering stems. The total yield from regimes with 13 mol m⁻² day⁻¹ was higher when the light was spread over 20 and 16 h compared to 12 h. In treatments with soil cooling, the plants flowered continuously under all combinations of photoperiods and photosynthetic fluence rates, and the summer and autumn recession in flower production that occurred for non-cooled ‘King Cardinal' and ‘Diamond' was the same under all lighting regimes. It is concluded that it might be more cost-effective to spread the daily investment of light over 20 rather than 16 or 12 h when the total energy budget and CO₂ costs are taken into consideration.     

Post-embryonic development of Camallanus cotti (Nematoda: Camallanidae), with emphasis on growth of some taxonomically important somatic characters

In this paper, the quantitative post-embryonic development of the Asian freshwater fish nematode Camallanus cotti Fujita, 1927, is described. Larval and adult morphometrics were obtained by following the parasite's life cycle experimentally using copepods Macrocyclops albidus (Jurine) as intermediate host and guppies Poecilia reticulata (Peters), southern platyfish Xiphophorus maculatus (Günther) and paradise fish Macropodus opercularis (L.) as definitive host. Additionally, adult worms were obtained from heavily infected paradise fish imported from Singapore. It is suggested that the gradual change in proportions of the worm's somatic body parts reflects the specific ecological role of each developmental stage. The free-living infective first-stage larva seems to be adapted for transmission, as indicated by its relatively long tail, designed to generate host-attracting movements, and its non-functional intestine. The second- and third-stage larvae from the copepod intermediate host seem mainly to invest in trophic functionality, i.e., the development of the buccal capsule and the oesophagus, which are crucial structures for the worm's successful establishment in the definitive fish host. Once in the fish intestine, the larvae enter a period of considerable growth. After the fourth (i.e., last) moult, a 72% increase in average female body length occurs. This is accompanied by doubling the average vulva-tail tip distance and the average tail length. The length of the female hind body expands in an accelerating allometric fashion, and seems to be closely linked to the posterior-wards expansion of the uterus. In the males however, growth seems to cease after the final moult. We conclude that female post-maturational body size, but especially the length of the hind body and the tail, are closely related to reproductive state, i.e., the developmental stage of the offspring in the uterus, and, probably, the worms' age. Any future taxonomical studies of camallanids in general, and C. cotti in particular, should thus be aware of the reproductive state of the females used.     

Effects of photoperiod on sex steroids and gonad maturation in Arctic charr

Four groups of Arctic charr (age 3+), previously exposed to natural photoperiod, were subjected to different photoperiod regimes from February 20: Simulated natural photoperiod (SNP; Tromsø 70°N), continuous light (LD 24:0) followed by short day (LD 6:18) from either May 1 (L_Feb–May) or June 25 (L_Feb–June), or continuous light (LD 24:0) throughout the experiment (L_Continuous). In females, peak levels of estradiol-17β and testosterone were 6 and 10, 6 and 7, and 3 and 5 weeks advanced, in L_Feb–May, L_Feb–June and L_Continuous, respectively, whereas in males plasma levels of 11-ketotestosterone peaked 8 weeks earlier in L_Feb–May and L_Feb–June than in SNP and L_Continuous. Median ovulation time in L_Feb–May and L_Feb–June was advanced by 10 weeks compared to SNP and L_Continuous, and median spermiation time (first observation of running milt in each individual) in L_Feb–May, L_Feb–June and L_Continuous was advanced by 10, 7 and 5 weeks, compared to SNP. A switch from long to short day early in the reproductive cycle (L_Feb–May and L_Feb–June) apparently resulted in stronger synchronization of both ovulation and spermiation. Ovulation in L_Feb–May and L_Feb–June occurred over 3 weeks (L_Feb–May) and 8 weeks (L_Feb–June), as compared to 10 weeks in the SNP group, whereas all males (except one individual) began spermiating over a period of 3 weeks (L_Feb–June), or less (L_Feb–May), as compared to 7 weeks in the SNP group. Lack of a short day stimulus (L_Continuous), on the other hand, resulted in larger variation in the timing of final maturation, with ovulation and spermiation being spread over 15 weeks. Low egg survival in L_Feb–May (17% versus 60% and 97% for L_Continuous and SNP) indicate that a long day signal of 10 weeks early in the reproductive cycle may be too short to ensure good egg and sperm quality. Photoperiod manipulation did not affect the proportion of maturing fish.