The Determination of Nematode Tolerance and Seedling Performance of The Selected Almond (Prunus amygdalus L.) Genotypes in Isparta Province

In the present study, selected almond genotypes in Keciborlu/Isparta region by Y?ld?r?m (2007) based on late blooming and superior nut chacteristics were used to evaluate seedling growth performances and the reaction to root knot nematodes. Seeds were planted on perlite medium and stored 60 days at +4 ^°C in order to break seed dormancy. After germinating, seedlings were transferred to plastic pots to evaluate seedling growth characteristics and remaining seedlings were inoculated with Meloidogyne javanica and Meloidogyne incognita in order to asses resistance status of the selected seedlings. The highest germination percentage was obtained from Genotype 54 (96.1?%), the highest plant was observed from Genotype 9 (62.18 cm), the longest primary root was found from Genotype 54 (30.28 cm), the average secondary root lenght was highest in Genotype 9 (31.04 cm) and the widest root collar was observed in Genotype 33 (8.38 mm). Seedling stem diameter changed between 4.76 mm (Genoype 40) to 7.67 mm (Genotype 33). The lowest variation for stem widht was observed in Genotype 55 (0.58?%) while the lowest variation for seedling hight was found in Genotype 33 (0.50?%). Evaluated almond genotypes showed different reactions to studied nematode species, M. javanica and M. incognita. Resistant reactions of almond genotypes to nematode species were classified as susceptible, tolerant and resistant based on gal index values. Genotype 9 and 31 classified as tolerant to M. javanica while Genotype 54 classified as resistant to M. incognita.     

Soil sodicity as a result of periodical drought

Soil sodicity development is a process that depends nonlinearly on both salt concentration and composition of soil water. In particular in hot climates, soil water composition is subject to temporal variation due to dry–wet cycles. To investigate the effect of such cycles on soil salinity and sodicity, a simple root zone model is developed that accounts for annual salt accumulation and leaching periods. Cation exchange is simplified to considering only Ca/Na exchange, using the Gapon exchange equation. The resulting salt and Ca/Na-balances are solved for a series of dry/wet cycles with a standard numerical approach. Due to the nonlinearities in the Gapon equation, the fluctuations of soil salinity that may be induced, e.g. by fluctuating soil water content, affect sodicity development. Even for the case that salinity is in a periodic steady state, where salt concentrations do not increase on the long term, sodicity may still grow as a function of time from year to year. For the longer term, sodicity, as quantified by Exchangeable Sodium Percentage (ESP), approaches a maximum value that depends on drought and inflowing water quality, but not on soil cation exchange capacity. Analytical approaches for the salinity and sodicity developing under such fluctuating regimes appear to be in good agreement with numerical approximations and are very useful for checking numerical results and anticipating changes in practical situations.     

Antiparasitic activity of the medicinal plant Dillenia suffruticosa against the marine leech Zeylanicobdella arugamensis (Hirudinea) and its phytochemical composition

Zeylanicobdella arugamensis (Annelida: Hirudinea), a marine parasitic leech, is currently affecting different species of cultured groupers, hybrid groupers, snappers and sea bass in Malaysia. Dillenia suffruticosa (Dilleniaceae), a medicinal plant found in Sabah, has been selected in our experiment to kill the leeches as a natural control method. The leech‐infested hybrid groupers were collected from aquaculture facilities, and the isolated leeches were challenged against methanol extract of D. suffruticosa leaves. The experiment was carried out using various concentrations of the extracts such as 25, 50 and 100 mg/ml. The methanol extract showed significant antiparasitic activity against Z. arugamensis with 100% mortality at a concentration of 100 mg/ml in 14.39 ± 3.75 min., followed by 50 and 25 mg/ml in 32.97 ± 9.29 and 41.77 ± 5.40 min., respectively. The phytochemical composition of the extract was determined using GC‐MS analysis to understand the nature of the principal compounds responsible for its antiparasitic properties. The leaves of D. suffruticosa demonstrated the presence of different bioactive compounds of various natures with varying percentages. Thus, it could be revealed that the methanol extract of D. suffruticosa mainly contains vital phytochemical compounds and showed an effective antiparasitic activity against the harmful leeches of hybrid groupers.     

Comparative genome analysis reveals a distinct influence of nucleotide composition on virus–host species‐specific interaction of prawn‐infecting nodavirus

Discovery of species‐specific interaction between the host and virus has drawn the interest of many researchers to study the evolution of the newly emerged virus. Comparative genome analysis provides insights of the virus functional genome evolution and the underlying mechanisms of virus–host interactions. The analysis of nucleotide composition signified the evolution of nodavirus towards host specialization in a host‐specific mutation manner. GC‐rich genome of betanodavirus was significantly deficient in UpA and UpU dinucleotides composition, whilst the AU‐rich genome of gammanodavirus was deficient in CpG dinucleotide. The capsid of MrNV and PvNV of gammanodavirus retains the highest abundance of adenine and uracil at the second codon position, respectively, which were found to be very distinctive from the other genera. ENC‐GC3 plot inferred the influence of natural selection and mutational pressure in shaping the evolution of MrNV RdRp and capsid, respectively. Furthermore, CAI/eCAI analysis predicts a comparable adaptability of MrNV in squid, Sepia officinalis than its natural host, Macrobrachium rosenbergii. Thus, further study is warranted to investigate the capacity of MrNV replication in S. officinalis owing to its high codon adaptation index.     

Recent update on the prevalence of Vibrio species among cultured grouper in Peninsular Malaysia

Vibrio infections are common among marine fish and lead to serious problems in the aquaculture sector. This study reports a recent occurrence of Vibrio species (spp.) isolated from cultured groupers in Peninsular Malaysia using the gyrB and pyrH genes. A total of 147 Vibrio strains were successfully isolated from 77 (64%) groupers using culture method and subjected to gyrB and pyrH sequencing for species identification and confirmation. Results showed that 89% of Vibrio strains were identified and clustered to six groups of Vibrio spp., while 11% were not clustered to any Vibrio spp. using the gyrB sequences. Meanwhile, by analysis of the pyrH sequences all the 147 Vibrio strains (100%) were successfully identified and clustered into 11 groups of Vibrio spp., including the gyrB non‐identified strains. The pyrH gene provides a better resolution for identification of Vibrio spp. compared with the gyrB gene. Thus, the pyrH gene was more suitable for a rapid determination of Vibrio spp. distribution in Peninsular Malaysia. Using the pyrH gene, our study found higher prevalence of Vibrio vulnificus (33%), V. alginolyticus (24%) and V. parahaemolyticus (22%), followed by V. rotiferianus (5%), V. harveyi (3%), V. tubiashii (2%), V. campbellii (2%), V. ponticus (1%), V. diabolicus (1%), V. owensii (1%) and others Vibrio sp. (7%). Thus, the results of this study revealed that the occurrence of pathogenic vibrios among grouper fish is still high in Malaysian aquaculture. In addition, the pyrH gene was proved as a suitable marker for rapid identification of Vibrio species compared with the gyrB gene.     

Effect of microalga-based diet on oxidative stress enzymes of African catfish,Clarias gariepinus

Here an indigenously isolated microalgal strain Ascochloris spp. cultivated in synthetic medium was evaluated as an aquaculture feed supplement. The daily dietary supplement includes microalgal feed (AF) and commercial diet feed (CF) (as control), respectively. These diets were fed separately to the juvenile Clarias gariepinus fishes (n = 4) under controlled conditions for an experimental period of 100 days. The protein, glycogen and lipid contents in the muscle extracts were found to be marginally higher in fishes that were fed with CF than AF diet. Similarly, CF fishes showed significantly higher glutathione-s-transferase, catalase, superoxide dismutase, and lipid peroxidase activities, except glutathione content. Zero mortality of the fishes with no significant difference in the overall body mass with the two dietary supplements strongly suggests that algal biomass could supplement the requisite nutrients for their metabolic activities. This preliminary investigation helps in exploring algal biomass as a potential alternative feed additive in the aquaculture industry.     

长白山林区主要可燃物类型地表可燃物载量分析

对长白山林区主要可燃物类型地表可燃物载量进行了对比分析和聚类分析。通过可燃物类型载量的对比分析,得出易燃的可燃物类型是云冷杉林(鱼鳞云杉103a)、落叶松林(115a)和云冷杉林(鱼鳞云杉80a),最不易燃的是岳桦林(142a)、白桦林(87a)和岳桦林(115a);释放能量最大的可燃物类型是落叶松林(115a),释放能量最小的可燃物类型是白桦林(87a)。通过各可燃物类型的1h时滞可燃物载量和地表总可燃物载量的聚类分析,可把13个可燃物类型化为6类。     

Development of a monoclonal antibody-based co-agglutination test to detect enterotoxigenic Escherichia coli isolated from diarrheic neonatal calves

Escherichia coli (E. coli) strains were collected from young diarrheic calves in farms and field. Strains that expressed the K99 (F5) antigen were identified by agglutination tests using reference antibodies to K99 antigen and electron microscopy. The K99 antigen from a selected field strain (SAR-14) was heat-extracted and fractionated on a Sepharose CL-4B column. Further purification was carried out by sodium deoxycholate treatment and/or ion-exchange chromatography. Monoclonal antibodies to purified K99 antigen were produced by the hybridoma technique, and a specific clone, NEK99-5.6.12, was selected for propagation in tissue culture. The antibodies, thus obtained, were affinity-purified, characterized and coated onto Giemsa-stained Cowan-I strain of Staphylococcus aureus (S. aureus). The antibody-coated S. aureus were used in a co-agglutination test to detect K99+ E. coli isolated from feces of diarrheic calves. The specificity of the test was validated against reference monoclonal antibodies used in co-agglutination tests, as well as in ELISA. Specificity of the monoclonal antibodies was also tested against various Gram negative bacteria. The developed antibodies specifically detected purified K99 antigen in immunoblots, as well as K99+ E. coli in ELISA and co-agglutination tests. The co-agglutination test was specific and convenient for large-scale screening of K99+ E. coli isolates.     

Growth,survival, and heavy metal (Cd and Ni) uptake of spinach (Spinacia oleracea) and fenugreek (Trigonella corniculata) in a biochar‐amended sewage‐irrigated contaminated soil

Irrigation of arable land with contaminated sewage waters leads to the accumulation of trace metals in soils with subsequent phyto‐/zootoxic consequences. In this study, biochar derived from cotton sticks was used to amend an agricultural silt‐loam soil that had been previously irrigated with trace metal contaminated sewage waters. Metal accumulation and toxicity to spinach (Spinacia oleracea) and fenugreek (Trigonella corniculata) was investigated by measuring concentrations of Cd and Ni in plant tissues and various photosynthetic and biochemical activities of plants. Positive impacts of biochar on both spinach and fenugreek were observed in terms of biomass production that increased from 29% to 36% in case of spinach, while for fenugreek this increase was 32% to 36%. In the control treatment there was an increase in malondialdihyde, soluble sugar, and ascorbic acid contents, indicating heavy metal stress. Biochar applications increased soluble proteins and amino acids in plants and reduced the uptake of Cd from 5.42 mg kg^?1 at control to 3.45 mg kg^?1 at 5% biochar amended soil and Ni (13.8 mg kg^?1 to 7.3 mg kg^?1 at 5% biochar) by the spinach plants. In fenugreek, the Cd was reduced from 7.72 mg kg^?1 to 3.88 mg kg^?1 and reduction in Ni was from 15.45 mg kg^?1 to 9.46 mg kg^?1 at 5% biochar treated soil, reducing the possibility of transfer up the food chain. This study demonstrates that the use of biochar made from cotton‐sticks, as an amendment to arable soils that have received contaminated irrigation water, could improve plant growth and decrease Cd and Ni uptake to crops, alleviating some of the negative impacts of using sewage waters on arable land.