Evidence for Resistance to Bacillus thuringiensis (Bt) subsp. kurstaki HD-1, Bt subsp. aizawai and Abamectin in Field Populations of Plutella xylostella from Malaysia

The efficacy of Bacillus thuringiensis (Bt) subsp. kurstaki HD-1 (‘Dipel’™; Btk; CryIA & CryII) and Bt. subsp. aizawai (‘Florbac’™; Bta; CryIA & CryIC) was assessed against larvae from various field populations of Plutella xylostella (F2 generation) collected in the Cameron Highlands, Malaysia in April 1994 and a lowland population (SERD 2; F10 generation) collected in December 1993. Evidence of resistance to Btk and to a lesser extent Bta is reported in these populations (LC₅₀ Toxicity Ratios [TR]=3–14 and 2–8 respectively), most notably in SERD 2. The first recorded evidence of resistance to abamectin (TR=17–195-fold) in field populations of P. xylostella is also reported. In an unselected sub-population of SERD 2, the TR values for Btk, Bta and abamectin declined 2- to 3-fold (P<0·01) over six generations in the laboratory (F10–F16) while in sub-populations of SERD 2 selected with these products (F11–F15) there was a significant (P<0·01) increase in the TR (15-, 3- and 2·5-fold respectively) when compared with the F10 generation. This suggests the presence of marked resistance to Btk and some resistance to Bta and abamectin. There is also evidence of slight cross-resistance to Btk in the Bta-selected sub-population but no evidence for the reverse selection of resistance or for cross-resistance between Btk and abamectin. Concurrent selection studies (F11–F15) with another sub-population of SERD 2 demonstrated resistance to the acylurea insect growth regulator, teflubenzuron (‘Nomolt’™) (29-fold increase in TR). Based on the selection experiments with SERD 2, estimates of realised heritability (h²) of resistance gave very high values for teflubenzuron and Btk (c.0·7) and moderate values for abamectin and Bta (c.0·3). The results are discussed in relation to integrated pest management (IPM) and insecticide resistance management (IRM) strategies for P. xylostella.     

Phytochemical study of Salvia moorcroftiana.

Four known flavonoids were isolated from the aerial parts of Salvia moorcroftiana.     

Application de la chromatographie en phase gazeuse au dosage du squalène dans les végétaux

Résumé Découvert il y a plus de 50 ans, dans des huiles de foies de squaloides, le squalène C₃₀ H₅₀ a été ensuite identifié et dosé dans plusieurs huiles d'origine végétale.Les auteurs décrivent une nouvelle méthode de dosage, plus spécifique et plus sensible, par chromatographie en phase gazeuse et déshydrogenation de la fraction insaponifiable de végétaux.Les teneurs sont, en mg pour 100 g, d'environ 150 pour l'huile d'olive, 4 pour les feuilles d'olivier, 2 pour la luzerne, 0,1 pour les feuilles de sureau, acanthe, laitue et les feuilles et racines de carottes.

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Summary Discovered more than 50 years ago in liver oils of squaloids, squalene C₃₀ H₅₀ was later identified and determined in several oils of vegetable origin.The authors describe a new, more specific, and more sensitive, method of determination by gas chromatography and dehydrogenation of the unsaponiüable fraction of plants.The contents are, in mg per 100 g, about 150 for olive oil, 4 for olive-tree leaves, 2 for alfalfa, 0.1 for the leaves of elder, acanthus, lettuce, and leaves and roots of carrots.

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Zusammenfassung Vor mehr als 50 Jahren im Lebertran von Haifischen entdeckt, wurde das Squalen später in mehreren Ölen pflanzlichen Ursprungs identifiziert und bestimmt.Die Verfasser beschreiben eine neue mehr spezifische und empfindliche Bestimmungsmethode mittels Gaschromatographie und Dehydrogenierung der unverseifbaren Fraktion der Pflanzen.Die Gehalte sind, in mg/100 g, ungefähr 150 für Olivenöl, 4 für die Blätter des Ölbaumes, 2 für Klee, 0,1 für die Blätter des Hollunders, für Bärenklau, für Kopfsalat sowie für Blätter und Wurzeln der Möhren.

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avec 1 fig.     

Nucleotide sequencing, whitefly transmission, and screening tomato for resistance against two newly described begomoviruses in bangladesh

ABSTRACT The molecular diversity of Tomato leaf curl viruses (ToLCVs), from the two main tomato growing areas of Jessore and Joydebpur, Bangladesh, was investigated. The viral DNA was amplified from tomato plants exhibiting mild and severe symptoms by polymerase chain reaction, and the complete genomes of the ToLCVs were sequenced. An isolate of the bipartite Tomato leaf curl New Delhi virus-Severe (ToLCNDV-Svr) was associated with the severe symptom phenotype from Jessore (ToLCNDV-Svr[Jes]). A previously undescribed monopartite virus, designated Tomato leaf curl Joydebpur virus-Mild (ToLCJV-Mld), was sequenced from plants showing mild symptoms. ToLCNDV-Svr[Jes] was most closely related to ToLCNDV-[Lucknow] at 95.7% nucleotide (nt) identity and Tomato leaf curl Gujarat virus-[Varanasi] at 90.6% nt identity, based on DNA-A and -B component sequences. ToLCJV-Mld was similar to Pepper leaf curl Bangladesh virus at 87.1% DNA-A nt identity. Identification of ToLCNDV-Svr[Jes] and ToLCJV-Mld was in addition to the previously described Tomato leaf curl Bangladesh virus, with which they shared 73.2 and 86.0% DNA-A nt identities, thus demonstrating the existence of at least three distinct viruses infecting tomato in Bangladesh. Nucleotide identities and placement in phylogenetic trees suggested that the three ToLCVs may have had different evolutionary pathways. The whitefly, Bemisia tabaci, transmitted the viruses of this study equally efficiently. Four tomato cultivars (TLB111, TLB130, TLB133, and TLB182) resistant/ tolerant to South Indian ToLCV were screened against the Bangladesh ToLCVs in 2003-04. Although challenged by diverse viruses and potentially mixed infections, disease incidence remained low (6 to 45%) in the resistant cultivars compared with local cultivars (68 to 100%).     

Assessment of Phosphorus Levels in Small Ruminants as Affected by Summer and Winter

An experiment was carried out to assess the phosphorus status of free grazing goats at Faisalabad,Pakistan.Samples were collected fortnightly during summer and winter seasons of 2010 from soil and plants.The highest(118±0.54 mg·kg-1)levels of feces phosphorus were recorded in lactating goats during winter and(9.87±0.99 mg·kg-1)in urine of male during winter.Similarly maximum(71.0±0.88 mg·kg-1)phosphorus concentration was observed in the plasma of lactating animals.Milk contained(31.0±0.36)mg·L-1 in winter while during the months of summer the highest values recorded in forages,soils,canal and tube well waters were(755±1.98)mg·kg-1,(785±4.98)mg·kg-1,(0.97±8.78)mg·L-1 and(4.12±0.55)mg·L-1,respectively.It was revealed from the current results that fecal matter,forage,milk,tube well and canal water contained lower amounts of P,while P levels in blood plasma was found within the critical limits.Therefore,phosphorus supplementations were required in the area under experimentation to meet the requirements of the animals for their normal growth.     

Kinesin and dynein move a peroxisome in vivo: a tug-of-war or coordinated movement?

We used fluorescence imaging with one nanometer accuracy (FIONA) to analyze organelle movement by conventional kinesin and cytoplasmic dynein in a cell. We located a green fluorescence protein (GFP)-tagged peroxisome in cultured Drosophila S2 cells to within 1.5 nanometers in 1.1 milliseconds, a 400-fold improvement in temporal resolution, sufficient to determine the average step size to be approximately 8 nanometers for both dynein and kinesin. Furthermore, we found that dynein and kinesin do not work against each other in vivo during peroxisome transport. Rather, multiple kinesins or multiple dyneins work together, producing up to 10 times the in vitro speed.     

Synteny and collinearity in plant genomes

Correlated gene arrangements among taxa provide a valuable framework for inference of shared ancestry of genes and for the utilization of findings from model organisms to study less-well-understood systems. In angiosperms, comparisons of gene arrangements are complicated by recurring polyploidy and extensive genome rearrangement. New genome sequences and improved analytical approaches are clarifying angiosperm evolution and revealing patterns of differential gene loss after genome duplication and differential gene retention associated with evolution of some morphological complexity. Because of variability in DNA substitution rates among taxa and genes, deviation from collinearity might be a more reliable phylogenetic character.     

Arsenic chemistry in a groundwater aquifer from the Eastern Province of Saudi Arabia

Groundwater samples were collected from shallow aquifers underneath an industrial complex in the Eastern Province of Saudi Arabia. Arsenic (As) concentrations in the groundwater samples varied between 10^?8.6 and 10^?6.8 M (0.18 and 11.14 µg L^?1), with an average of 10^?7.5 M (2.19 μ L^?1). The analysis of variance for the analytical data showed that sampling locations had significantly affected As concentrations in the groundwater samples. Analytical and thermodynamic calculations showed that H₂ASO₄ ^? was the most predominant As species in acidic groundwater samples, and HAsO₄ ^2? was the most abundant species in alkaline groundwater samples. Concentrations of H₃AsO₄° and AsO₄ ^3? were too low to be important in this study. Reduced As chemical forms were also expected to be very low. All the groundwater samples were undersaturated with respect to the thermodynamic solubility isotherms of Ca₃(AsO₄)₂(c), Fe₃(AsO₄)₂(c), and Mn₃(AsO₄)₂(c) minerals. Lack of reliable thermodynamic data for these arsenates could be responsible for differences between the theoretical and measured concentrations of As in the shallow groundwater samples. The general trend in the distribution of HAsO₄ ^2? activities in the groundwater samples was parallel to that of the Ca₃(AsO₄)₂ solubility isotherm but different from those of Fe₃(AsO₄)₂(c), and Mn₃(AsO₄)₂(c). These data suggest that As concentrations in the groundwater samples were probably controlled by the precipitation and dissolution of Ca₃(AsO₄)₂ type mineral. A three step hypothesis for As interactions in groundwater/soil system is proposed that combines both solid phase formation and adsorption of As onto the solid colloidal surfaces. This hypothesis is expected to better represent As behavior in groundwater/soil environment.     

Effect of environmental factors on estrus synchronization and artificial insemination success in farmers flock in sheep under semi-arid tropical region

Environmental cues in the different seasons might influence the estrus and lambing percentages. The present study was conducted to assess the effect of environmental factors on estrus synchronization (ES) and artificial insemination success in sheep . During the period from 2012 to 2017, a total of 1,197 ewes of Kheri and Malpura breeds of 34 farms originating from 10 villages were synchronized for estrus and then fixed-time artificial insemination (FTAI) was done. Oestrous synchronization was done by intravaginal progesterone sponges and eCG protocol. Fixed-time cervical insemination was performed 48 and 56 hr after sponge removal in ewes exhibiting estrus, using liquid chilled semen containing 100 million sperm per dose of Patanwadi/Malpura rams. Mean sunshine hours, maximum and minimum ambient temperatures, temperature amplitude, mean relative humidity (RH), temperature-humidity index (THI), mean temperature during sponge-in to sponge-out—12-day period, sponge-out and next day, AI day and AI to next 15 days have been calculated. The estrus response and lambing percentage were higher (p < .05) when ES and FTAI were done during hot-humid with rainfall season. Successful (p < .05) ES occur when the minimum temperature was higher in cold-humid season, and the sunshine hour was higher in hot-humid with scanty rainfall season during sponge-in to sponge-out period. The success of the lambing percentage was higher (p < .05) when maximum temperature, minimum temperature, mean temperature and THI was higher on the day of AI and the next 15-day period, irrespective of the season. The success of FTAI indicates the adaptability of the local breed to tolerate the harsh climate of the hot semi-arid region without much hindrance in lambing percentages.     

Delineating soil nutrient management zones based on optimal sampling interval in medium- and small-scale intensive farming systems

Precision Agriculture - Soil nutrients vary greatly and information regarding their spatial-temporal variability is critical for achieving site-specific nutrient management. However, the problem is...