DETECTION OF PHYTOPLASMAS ASSOCIATED WITH KALIMANTAN WILT DISEASE OF COCONUT BY THE POLYMERASE CHAIN REACTION

ABSTRACTCoconut is the second Indonesia’s most important social commodityafter rice. There are more than 3.6 million hectares of coconut plantationsin Indonesia equivalent to one third of the total world coconut area.However, the production and productivity of the coconut are very low andunstable for various reasons, including pests and diseases. Kalimantan wilt(KW) disease causes extensive damage to coconut plantation. In previousinvestigations, bacteria, fungi, viruses, viroids and soil-borne pathogenssuch as nematodes were tested, but none of them were consistentlyassociated with the disease. The objective of this research was to detectand diagnose the phytoplasma associating with KW. Two DNA extractionmethods, namely a modification of CTAB method involving grindingcoconut trunk tissue in pre-warmed CTAB instead of liquid nitrogen, and asmall scale DNA extraction method, were used to prepare DNA fromcoconut trunk tissues. Research results showed that both methods werefound equally suitable for preparing DNA from coconut trunk tissues forPCR analysis. The phytoplasmas aetiology of KW has been proved by thenested PCR approach using P1/P7 and R16F2n/R16R2 primercombinations. The study has further demonstrated that the nested PCRapproach can be employed to effectively detect the presence ofphytoplasma both in infected and in symptomless coconut trunk tissues.Phytoplasma DNA was amplified from 95 out of 116 samples (81.9%).Based on source of samples, phytoplasma DNA was amplified from KWinfected and symptomless samples, 95.1% and 67.3% respectively. Thisstudy confirmed that KW is caused by phytoplasma.Key words : Coconut, Cocos nucifera L., plant disease, Kalimantan wiltdisease, phytoplasma, polymerase chain reaction, CentralKalimantanABSTRAKDeteksi phytoplasma yang berasosiasi dengan penyakitlayu Kalimantan pada kelapa dengan reaksi rantaipolymeraseKelapa merupakan komoditi sosial kedua setelah padi di Indonesiadengan luasan areal lebih dari 3.6 juta ha pertanaman, ekuivalen dengansepertiga luas kelapa dunia, hal ini menjadikan Indonesia sebagai negaraprodusen kelapa terluas di dunia. Sekarang ini produksi dan produktivitaskelapa sangat rendah dan tidak stabil yang disebabkan oleh berbagai alasantermasuk serangan hama dan penyakit. Penyakit layu Kalimantan telahmengakibatkan kerugian yang besar pada pertanaman kelapa. Penelitiansebelumnya untuk mengetahui penyebab penyakit dilakukan denganmenguji bakteri, cendawan, virus, viroid dan patogen tanah sepertinematoda tetapi tidak ada yang secara konsisten berasosiasi denganpenyakit layu Kalimantan. Penelitian ini bertujuan untuk mendeteksi danmendiagnosa phytoplasma sebagai penyebab penyakit yang berasosiasidengan layu Kalimantan. Penelitian ini menggunakan dua metode untukmengekstraksi DNA yaitu metode CTAB yang biasanya menggunakannitrogen cair dimodifikasi dengan menghancurkan sampel tanaman padaCTAB yang dipanaskan, dan metode skala kecil. Hasil penelitianmenunjukkan bahwa kedua metode yang digunakan menghasilkan DNAyang sama baiknya untuk analisis PCR. Teknik nested PCR menggunakankombinasi primer P1/P7 dan R16F2n/R16R2 dapat membuktikan bahwapenyebab penyakit layu Kalimantan adalah phytoplasma. Teknik ini jugasecara efektif dapat mendeteksi phytoplasma dalam jaringan tanamankelapa yang sudah terinfeksi maupun yang belum menunjukkan gejalapenyakit. DNA phytoplasma dapat dideteksi pada 95 sampel dari 116sampel (81.9%) yang dianalisis. Berdasarkan jenis sample yang diperiksaternyata phytoplasma dapat dideteksi pada sample yang terinfeksi maupunyang belum menunjukkan gejala penyakit masing-masing 95.1% dan67.3%. Hasil penelitian ini mengkonfirmasi bahwa penyakit layuKalimantan disebabkan oleh phytoplasma.Kata kunci: Kelapa, Cocos nucifera L., penyakit tanaman, penyakit layuKalimantan,  phytoplasma,  reaksi  rantai  polymerase,Kalimantan Tenga

Effect of food on absorption of lomefloxacin

Twelve subjects participated in an open-label, single-dose, balanced three-way crossover study in which the absorptions of lomefloxacin were compared following (i) an overnight fast, (ii) a carbohydrate meal, and (iii) a high-fat meal. The time to peak concentration of lomefloxacin was delayed, but peak concentration in plasma and amount of drug absorbed were unchanged following both meals

Exercise and Academic Achievement in Children: Effects of Acute Class-Based Circuit Training

Purpose. For schools, the increasingly imposed requirement to achieve well in academic tests puts increasing emphasis on improving academic achievement. While treadmill exercise has been shown to have beneficial effects on cognitive function and cycling ergometers produce stronger effect sizes than treadmill running, it is impractical for schools to use these on a whole-class basis. There is a need to examine if more ecologically valid modes of exercise might have a similar impact on academic achievement. Circuit training is one such modality shown to benefit cognitive function and recall ability and is easily operationalised within schools. Methods. In a repeated measures design, twenty-six children (17 boys, 8 girls) aged 10-11 years (mean age 10.3; SD ± 0.46 years) completed the Wide Range Achievement Test (WRAT 4) at rest and following 30 minutes of exercise. Results. Standardised scores for word reading were significantly higher post exercise (F(1,18) = 49.9, p = 0.0001) compared to rest. In contrast, standardised scores for sentence comprehension (F(1,18) = 0.078, p = 0.783), spelling (F(1,18) = 4.07, p = 0.06) mathematics (F(1,18) = 1.257, p = 0.277), and reading (F(1,18) = 2.09, p = 0.165) were not significantly different between rest and exercise conditions. Conclusions. The results of the current study suggest acute bouts of circuit based exercise enhances word reading but not other areas of academic ability in 10-11 year old children. These findings support prior research that indicates acute bouts of exercise can selectively improve cognition in children

The response of soil microbial diversity and abundance to long-term application of biosolids

The disposal of biosolids poses a major environmental and economic problem. Agricultural use is generally regarded as the best means of disposal. However, its impact on soil ecosystems remains uncertain. Biosolids can improve soil properties by supplying nutrients and increasing organic matter content but there is also a potentially detrimental effect arising from the introduction of heavy metals into soils. To assess the balance between these competing effects on soil health, we investigated soil bacterial and fungal diversity and community structure at a site that has been dedicated to the disposal of sewage sludge for over 100 years. Terminal restriction fragment length polymorphism (T-RFLP) was used to characterize the soil microbial communities. The most important contaminants at the site were Ni, Cu, Zn, Cd, and Pb. Concentrations were highly correlated and Zn concentration was adopted as a good indicator of the overall (historical) biosolids loading. A biosolids loading, equivalent to 700–1000 mg kg−1 Zn appeared to be optimal for maximum bacterial and fungal diversity. This markedly exceeds the maximum soil Zn concentration of 300 mg kg−1permitted under the current UK Sludge (use in agriculture) Regulations. Redundancy analysis (RDA) suggested that the soil microbial communities had been altered in response to the accumulation of trace metals, especially Zn, Cd, and Cu. We believe this is the first time the trade-off between positive and negative effects of long term (>100 years) biosolids disposal on soil microorganisms have been observed in the field situation

p-wave phase shift and scattering length of 6^6Li

We have calculated the p-wave phase shifts and scattering length of $^6$Li. For this we solve the $p$ partial wave Schr\"odinger equation and analyze the validity of adopting the semiclassical solution to evaluate the constant factors in the solution. Unlike in the $s$ wave case, the semiclassical solution does not provide unique value of the constants. We suggest an approximate analytic solution, which provides reliable results in special cases. Further more, we also use the variable phase method to evaluate the phase shifts. The p-wave scattering lengths of $^{132}$Cs and $^{134}$Cs are calculated to validate the schemes followed. Based on our calculations, the value of the $p$ wave scattering length of $^6$Li is $-45a_o$.Comment: 10 figure

Social reward among juvenile mice

Mammalian social relationships, such as mother–offspring attachments and pair bonds, can directly affect reproductive output. However, conspecifics approach one another in a comparatively broad range of contexts, so conceivably there are motivations for social congregation other than those underlying reproduction, parental care or territoriality. Here, we show that reward mediated by social contact is a fundamental aspect of juvenile mouse sociality. Employing a novel social conditioned place preference (SCPP) procedure, we demonstrate that social proximity is rewarding for juvenile mice from three inbred strains (A/J, C57BL/6J and DBA/2J), while mice from a fourth strain (BALB/cJ) are much less responsive to social contact. Importantly, this strain-dependent difference was not related to phenotypic variability in exploratory behavior or contextual learning nor influenced by the genetic background associated with maternal care or social conditioning. Furthermore, the SCPP phenotype was expressed early in development (postnatal day 25) and did not require a specific sex composition within the conditioning group. Finally, SCPP responses resulted from an interaction between two specifiable processes: one component of the interaction facilitated approach toward environments that were associated with social salience, whereas a second component mediated avoidance of environmental cues that predicted social isolation. We have thus identified a genetically prescribed process that can attribute value onto conditions predicting a general form of social contact. To our knowledge, this is the first definitive evidence to show that genetic variation can influence a form of social valuation not directly related to a reproductive behavior

The History of Galaxy Formation in Groups: An Observational Perspective

We present a pedagogical review on the formation and evolution of galaxies in groups, utilizing observational information from the Local Group to galaxies at z~6. The majority of galaxies in the nearby universe are found in groups, and galaxies at all redshifts up to z~6 tend to cluster on the scale of nearby groups (~1 Mpc). This suggests that the group environment may play a role in the formation of most galaxies. The Local Group, and other nearby groups, display a diversity in star formation and morphological properties that puts limits on how, and when, galaxies in groups formed. Effects that depend on an intragroup medium, such as ram-pressure and strangulation, are likely not major mechanisms driving group galaxy evolution. Simple dynamical friction arguments however show that galaxy mergers should be common, and a dominant process for driving evolution. While mergers between L_* galaxies are observed to be rare at z < 1, they are much more common at earlier times. This is due to the increased density of the universe, and to the fact that high mass galaxies are highly clustered on the scale of groups. We furthermore discus why the local number density environment of galaxies strongly correlates with galaxy properties, and why the group environment may be the preferred method for establishing the relationship between properties of galaxies and their local density.Comment: Invited review, 16 pages, to be published in ESO Astrophysics Symposia: "Groups of Galaxies in the Nearby Universe", eds. I. Saviane, V. Ivanov, J. Borissov

Resilience Measurement Index: An Indicator of Critical Infrastructure Resilience

56 p. ; col. ill

Configuration-interaction calculations of positron binding to zinc and cadmium

The configuration-interaction method is applied to the study of positronic zinc (e+Zn) and positronic cadmium (e+Cd). The estimated binding energies and annihilation rates were 0.00373 hartree and 0.42&times;109 sec-1 for e+Zn and 0.006 10 hartree and 0.56&times;109 sec-1 for e+Cd. The low-energy elastic cross section and Zeff were estimated from a model potential that was tuned to the binding energies and annihilation rates. Since the scattering lengths were positive (14.5a0 for Zn and 11.6a0 for Cd) the differential cross sections are larger at backward angles than at forward angles just above threshold. The possibilities of measuring differential cross sections to confirm positron binding to these atoms is discussed