Antibiosis and antixenosis of six commonly produced potato cultivars to the green peach aphid, Myzus persicae Sulzer (Hemiptera: Aphididae)

The antibiotic and antixenotic resistance of six commonly produced potato cultivars in Iran including Aozonia, Agria, Cosima, Cosmos, Kondor and Savalan to the green peach aphid, Myzus persicae Sulzer, were investigated under laboratory conditions at 20 ± 2oC, 65 ± 5% RH and 16:8h (L:D) in 2009. Antibiosis experiments showed significant differences in the developmental time, nymphal survivorship, fecundity, adult longevity of the green peach aphid among the potato cultivars. Intrinsic rate of natural increase (r m) for apterous aphids varied significantly with the potato cultivars on which the aphids were reared. This value ranged from 0.225 to 0.293 females/female/day, which was lowest on Cosmos and highest on Aozonia. Additionally, the estimated net reproductive rate (R0) and finite rate of increase (λ) for apterous aphids were the lowest on Cosmos. For the antixenosis experiment, no significant difference was found in aphid's preference to the potato cultivars. However, Aozonia was preferred more than the other five cultivars by the apterous aphids. Therefore, our results demonstrated that among the investigated cultivars the Cosmos cultivar is moderately resistant to the green peach aphid.     

A genomic integration method for the simultaneous visualization of endogenous mRNAs and their translation products in living yeast

Protein localization within cells can be achieved by the targeting and localized translation of mRNA. Yet, our understanding of the dynamics of mRNA targeting and protein localization, and of how general this phenomenon is, is not clear. Plasmid-based expression systems have been used to visualize exogenously expressed mRNAs and proteins; however, these methods typically produce them at levels greater than endogenous and can result in mislocalization. Hence, a method that allows for the simultaneous visualization of endogenous mRNAs and their translation products in living cells is needed. We previously developed a method (m-TAG) to localize endogenously expressed mRNAs in yeast by chromosomal insertion of the MS2 aptamer sequence between the open-reading frame (ORF) and 3' UTR of any gene. Upon coexpression with the MS2 RNA-binding coat protein (MS2-CP) fused with GFP, the aptamer-tagged mRNAs bearing their 3' UTRs are localized using fluorescence microscopy. Here we describe an advanced method (mp-TAG) that allows for the simultaneous visualization of both endogenously expressed mRNAs and their translation products in living yeast for the first time. Homologous recombination is used to insert the mCherry gene and MS2-CP binding sites downstream from any ORF, in order to localize protein and mRNA, respectively. As proof of the concept, we tagged ATP2 as a representative gene and demonstrated that endogenous ATP2 mRNA and protein localize to mitochondria, as shown previously. In addition, we demonstrate that tagged proteins like Hhf2, Vph1, and Yef3 localize to their expected subcellular location, while the localization of their mRNAs is revealed for the first time.     

Impact of Chemical,Organic and Bio-Fertilizers Application on Bell Pepper, <Emphasis Type="Italic">Capsicum annuum</Emphasis> L. and Biological Parameters of <Emphasis Type="Italic">Myzus persicae</Emphasis> (Sulzer) (Hem.: Aphididae)

Myzus persicae (Sulzer) is a polyphagous aphid that causes chlorosis, necrosis, stunting, and reduce growth rate of the host plants. In this research, the effects of Zinc sulfate and vermicompost (30%), Bacillus subtilis, Pseudomonas fluorescens, Glomus intraradices, G. intraradices × B. subtilis, and G. intraradices × P. fluorescens compared to control was investigated on the growth characters of Capsicum annuum L. and biological parameters of M. persicae. Different fertilizers caused a significant effect on growth characters of C. annuum and biological parameters of M. persicae. The highest plant growth was observed on Zinc sulfate and B. subtilis treated plants, and the lowest was on control. Increase in the amount of specific leaf area (SLA) (0.502 mm² mg^?1) was significantly higher in the B. subtilis than other fertilizer treatments. The longest (10.3 days) and the shortest (5.3 days) developmental times of M. persicae nymphs were observed on 30% vermicompost and Zinc sulfate treatments, respectively. The lowest adult longevity periods of M. persicae (11.2 and 11.3 days) were observed on G. intraradices × B. subtilis and 30% vermicompost treatments, respectively, and the longest ones (16.4 days) on Zinc sulfate. The highest rate of nymphal mortality and the lowest amount of nymphal growth index (NGI) were recorded on 30% vermicompost. The nymphs reared on Zinc sulfate treatment had the lowest rate of nymphal mortality and the highest amount of NGI. Thus, amending the soil with 30% vermicompost had a significantly negative effect on the biological parameters of M. persicae that can be used as an ecological control tactic for this pest.     

The Arabian race camel normal parameters--I. Haemogram, enzymes and minerals

1. Racing camels' (Camelus dromedarius) normal blood parameters were determined in Al-Ain, U.A.E. The parameters were: packed cell volume, haemoglobin, total red and white blood cells, the activities of glutamate oxaloacetate (GOT), creatinine kinase (CK), gamma-glutamyl transferase (gamma-GT) and CK muscle-brain isoenzyme and the concentrations of creatinine, urea, total protein, albumin, calcium, magnesium, phosphorus, sodium, potassium, zinc, copper and iron. 2. Most blood parameters were found to differ from those of other domestic animals and from non-race camels. 3. The data are discussed in relation to the management system practised.     

Regulation of mTORC1 and mTORC2 Complex Assembly by Phosphatidic Acid: Competition with Rapamycin

mTOR, the mammalian target of rapamycin, is a critical node for control of cell growth and survival and has widely been implicated in cancer survival signals. mTOR exists in two complexes: mTORC1 and mTORC2. Phospholipase D (PLD) and its metabolite phosphatidic acid (PA) have been implicated in the regulation of mTOR; however, their role has been controversial. We report here that suppression of PLD prevents phosphorylation of the mTORC1 substrate S6 kinase (S6K) at Thr389 and the mTORC2 substrate Akt at Ser473. Suppression of PLD also blocked insulin-stimulated Akt phosphorylation at Ser473 and the mTORC2-dependent phosphorylation of PRAS40. Importantly, PA was required for the association of mTOR with Raptor to form mTORC1 and that of mTOR with Rictor to form mTORC2. The effect of PA was competitive with rapamycin—with much higher concentrations of rapamycin needed to compete with the PA-mTORC2 interaction than with PA-mTORC1. Suppressing PA production substantially increased the sensitivity of mTORC2 to rapamycin. Data provided here demonstrate a PA requirement for the stabilization of both mTORC1 and mTORC2 complexes and reveal a mechanism for the inhibitory effect of rapamycin on mTOR. This study also suggests that by suppressing PLD activity, mTORC2 could be targeted therapeutically with rapamycin.It has become apparent during the past decade that a critical aspect of tumor progression is the suppression of default apoptotic programs that constitute what is likely the most important protection against cancer. Cellular signals that suppress apoptosis have come to be known as “survival signals.” A common node for survival signals is mTOR, the mammalian target of rapamycin (5, 13, 14, 25). mTOR exists in two distinct complexes, mTORC1 and mTORC2 (21), that differ in their subunit composition and sensitivity to rapamycin. mTORC1 consists of a complex that includes mTOR and a protein known as Raptor (regulatory associated protein of mTOR), whereas mTORC2 consists of a complex that includes mTOR and a protein known as Rictor (rapamycin-insensitive companion of mTOR) (13, 14). There are also mTORC2 complexes that can be distinguished by association with different isoforms of mSin1 (9). While much is known about the regulation of mTORC1 (21), very little is known about the regulation of mTORC2.mTORC1 is highly sensitive to rapamycin, whereas mTORC2 is relatively insensitive to rapamycin (21). However, it was recently reported that long-term exposure to rapamycin prevented the formation of mTORC2 complexes and blocked the phosphorylation of the mTORC2 substrate Akt at Ser473 (24, 38). Rapamycin, in association with FK506 binding protein 12 (FKBP12), has been reported to interact with mTOR in a manner that is competitive with phosphatidic acid (PA), the metabolic product of phospholipase D (PLD) (2, 4). PLD, like mTOR, has been implicated in survival signals in several human cancer cell lines (1, 10, 11, 27, 32, 39). Since rapamycin-FKBP12 competes with PA for binding to mTOR, the sensitivity of mTORC2 complex formation to rapamycin suggests that PA facilitates the assembly of mTORC2—and ultimately the activation of mTORC2. We report here that the assembly of both mTORC1 and mTORC2 complexes is dependent upon PLD and its metabolite PA. The study also provides mechanistic insight into how rapamycin impacts on mTOR-mediated signals and how PLD regulates mTOR by facilitating the formation of mTOR complexes.     

Comparative damage and digestive enzyme activity of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) on 12 tomato cultivars

The damage caused by the tomato leaf miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) to 12 tomato cultivars was investigated under greenhouse conditions. The 2 cultivars Korral and CH Falat experienced lower damage in terms of all parameters investigated, whereas the cultivars Valouro and Cal JN3 were categorized as the most susceptible host plants. The larvae feeding on CH Falat and Korral cultivars reached the lowest final weight (1.82 and 1.93 mg, respectively), whereas those reared on the Valouro and Cal JN3 cultivars reached the highest body weight (3.42 and 3.33 mg, respectively). The highest proteolytic and amylolytic activity was detected in larvae feeding on the Korral cultivar, whereas larvae reared on the Valouro cultivar had the lowest enzyme activity for both third and fourth instar larvae. Altogether, the Korral and CH Falat cultivars were classified as relatively resistant cultivars, whereas the 2 cultivars Valouro and Cal JN3 were categorized as highly susceptible to infection by T. absoluta. Therefore, the resistant cultivars can be considered as candidates for use in integrated management programs of the tomato leaf miner in Iran.     

Differential dependence of hypoxia-inducible factors 1 alpha and 2 alpha on mTORC1 and mTORC2

Constitutive expression of hypoxia-inducible factor (HIF) has been implicated in several proliferative disorders. Constitutive expression of HIF1 alpha and HIF2 alpha has been linked to a number of human cancers, especially renal cell carcinoma (RCC), in which HIF2 alpha expression is the more important contributor. Expression of HIF1 alpha is dependent on the mammalian target of rapamycin (mTOR) and is sensitive to rapamycin. In contrast, there have been no reports linking HIF2 alpha expression with mTOR. mTOR exists in two complexes, mTORC1 and mTORC2, which are differentially sensitive to rapamycin. We report here that although there are clear differences in the sensitivity of HIF1 alpha and HIF2 alpha to rapamycin, both HIF1 alpha and HIF2 alpha expression is dependent on mTOR. HIF1 alpha expression was dependent on both Raptor (a constituent of mTORC1) and Rictor (a constitutive of mTORC2). In contrast, HIF2 alpha was dependent only on the mTORC2 constituent Rictor. These data indicate that although HIF1 alpha is dependent on both mTORC1 and mTORC2, HIF2 alpha is dependent only on mTORC2. We also examined the dependence of HIF alpha expression on the mTORC2 substrate Akt, which exists as three different isoforms, Akt1, Akt2, and Akt3. Interestingly, the expression of HIF2 alpha was dependent on Akt2, whereas that of HIF1 alpha was dependent on Akt3. Because HIF2 alpha is apparently more critical in RCC, this study underscores the importance of targeting mTORC2 and perhaps Akt2 signaling in RCC and other proliferative disorders in which HIF2 alpha has been implicated.     

Life history parameters of <Emphasis Type="Italic">Thrips tabaci</Emphasis> (Thysanoptera: Thripidae) on six commercial cultivars of canola

The onion thrips, Thrips tabaci Lind. (Thysanoptera: Thripidae), is an important pest of the canola crop, Brassica napus L., in the Ardabil region. In this study, life history parameters of T. tabaci were investigated on six canola cultivars, namely: Talayh, Zarfam, RGS003, Opera, Option500, and Hayola401. Experiments were performed in a climate chamber set at 25 ± 1°C and 55 ± 5% RH under 16L:8D. The results indicated that the development time of immature stages was significantly longer on RGS003 than on Opera, Hyola401, Zarfam, Option500, and Talayh. The onion thrips reared on RGS003 had the lowest number of eggs laid per female (15.5) and the lowest survival rate (40%) among the tested cultivars. The lowest intrinsic rate of natural increase (r _m) and population growth rate (λ) were observed on RGS003, and were the highest on Zarfam. The generation time (T) was shortest on Zarfam (21.5 days) and longest on RGS003 (26.5 days). Similarly, the doubling time (DT) was shortest on Zarfam (4.5 days) and longest on RGS003 (8.1 days). Considering the significant effect of the host plant on the life history parameters of onion thrips, it was concluded that RGS003 is the least suitable cultivar among the other tested canola cultivars for integrated management of onion thrips in canola fields.     

Resistance and susceptibility of various wheat varieties to <Emphasis Type="Italic">Sitobion avenae</Emphasis> (Hemiptera: Aphididae) in Iran

The English grain aphid, Sitobion avenae (Fabricius), is a severe pest of wheat plants in temperate countries. Therefore, we carried out primary screening to assess the resistance or susceptibility of 23 commonly grown wheat varieties to this aphid at greenhouse and laboratory conditions in Iran. Also, population attributes of this aphid were evaluated on six wheat varieties, namely Saysonz, Arta, Moghan3, Zagros, Sardari and Shirodi. The aphids were colonized on the Hirmand wheat variety in a growth chamber at 20 ± 1°C, 60 ± 5% R.H. and a photoperiod of 14:10 (L:D). The tested varieties were grouped into three major classes including A (e.g., Shirodi, Falat and Moghan2), B (e.g., Sardari, Zagros and Tagan) and C (e.g., Arta, Saysonz, Moghan3 and Pishtaz). Also, the results of the life history traits showed that the developmental time of nymphal stage ranged from 7.5 days on Zagros to 10.8 days on Saysonz. The intrinsic rate of increase (r _m ) of S. avenae varied from 0.133 (day⁻¹) on Saysonz to 0.210 (day⁻¹) on Shirodi. Jackknife estimates of other population parameters on these varieties were evaluated. As a result, our findings showed that the varieties Saysonz, Arta and Moghan3 were partially resistant against S. avenae, whereas Shirodi, Zagros and Sardari were relatively susceptible.