Plasticity in host utilization by two host-associated populations of Aphis gossypii Glover

Biological and morphological plasticity in polyphagous insect herbivores allow them to exploit diverse host plant species. Geographical differences in resource availability can lead to preferential host exploitation and result in inconsistent host specialization. Biological and molecular data provide insights into specialization and plasticity of such herbivore populations. In agricultural landscapes, Aphis gossypii encounters several crop and non-crop hosts, which exist in temporal and spatial proximity. We investigated the host-specialization of two A. gossypii host-associated populations (HAPs), which were field collected from cotton and squash (cotton-associated population and melon-associated population), and later maintained separately in the greenhouse. The two aphid populations were exposed to seven plant species (cotton, okra, watermelon, squash, cucumber, pigweed, and morning glory), and evaluated for their host utilization plasticity by estimating aphid's fitness parameters (nymphal period, adult period, fecundity, and intrinsic rate of increase). Four phenotypical characters (body length, head capsule width, hind tibia length and cornicle length) were also measured from the resulting 14 different HAP × host plant combinations. Phylogenetic analysis of mitochondrial COI sequences showed no genetic variation between the two HAPs. Fitness parameters indicated a significant variation between the two aphid populations, and the variation was influenced by host plants. The performance of melon-aphids was poor (up to 89% reduction in fecundity) on malvaceous hosts, cotton and okra. However, cotton-aphids performed better on cucurbitaceous hosts, squash and watermelon (up to 66% increased fecundity) compared with the natal host, cotton. Both HAPs were able to reproduce on two weed hosts. Cotton-aphids were smaller than melon-aphids irrespective of their host plants. Results from this study suggest that the two HAPs in the study area do not have strict host specialization; rather they exhibit plasticity in utilizing several hosts. In this scenario, it is unlikely that host-associated A. gossypii populations would evolve into host-specific biotypes.

Evaluation of Alternatives to an Organophosphate Insecticide with Selected Cultural Practices: Effects on Thrips, Frankliniella fusca, and Incidence of Spotted Wilt in Peanut Farmscapes

Peanut growers use a combination of tactics to manage spotted wilt disease caused by thrips-transmitted Tomato spotted wilt virus (TSWV). They include planting TSWV-resistant cultivars, application of insecticides, and various cultural practices. Two commonly used insecticides against thrips are aldicarb and phorate. Both insecticides exhibit broad-spectrum toxicity. Recent research has led to the identification of potential alternatives to aldicarb and phorate. In this study, along with reduced-risk, alternative insecticides, we evaluated the effect of conventional versus strip tillage; single versus twin row seeding pattern; and 13 seed/m versus 20 seed/m on thips density, feeding injury, and spotted wilt incidence. Three field trials were conducted in Georgia in 2012 and 2013. Thrips counts, thrips feeding injuriy, and incidence of spotted wilt were less under strip tillage than under conventional tillage. Reduced feeding injury from thrips was observed on twin-row plots compared with single-row plots. Thrips counts, thrips feeding injury, and incidence of spotted wilt did not vary by seeding rate. Yield from twin-row plots was greater than yield from single-row plots only in 2012. Yield was not affected by other cultural practices. Alternative insecticides, including imidacloprid and spinetoram, were as effective as phorate in suppressing thrips and reducing incidence of spotted wilt in conjunction with cultural practices. Results suggest that cultural practices and reduced-risk insecticides (alternatives to aldicarb and phorate) can effectively suppress thrips and incidence of spotted wilt in peanut.

Genome-wide analysis identifies chickpea (Cicer arietinum) heat stress transcription factors (Hsfs) responsive to heat stress at the pod development stage

The heat stress transcription factors (Hsfs) play a prominent role in thermotolerance and eliciting the heat stress response in plants. Identification and expression analysis of Hsfs gene family members in chickpea would provide valuable information on heat stress responsive Hsfs. A genome-wide analysis of Hsfs gene family resulted in the identification of 22 Hsf genes in chickpea in both desi and kabuli genome. Phylogenetic analysis distinctly separated 12 A, 9 B, and 1 C class Hsfs, respectively. An analysis of cis-regulatory elements in the upstream region of the genes identified many stress responsive elements such as heat stress elements (HSE), abscisic acid responsive element (ABRE) etc. In silico expression analysis showed nine and three Hsfs were also expressed in drought and salinity stresses, respectively. Q-PCR expression analysis of Hsfs under heat stress at pod development and at 15 days old seedling stage showed that CarHsfA2, A6, and B2 were significantly upregulated in both the stages of crop growth and other four Hsfs (CarHsfA2, A6a, A6c, B2a) showed early transcriptional upregulation for heat stress at seedling stage of chickpea. These subclasses of Hsfs identified in this study can be further evaluated as candidate genes in the characterization of heat stress response in chickpea.

Design and development of a low cost, high current density power supply for streamer free atmospheric pressure DBD plasma generation in air

This paper presents a new power supply architecture for generating a uniform dielectric barrier discharge (DBD) plasma in air medium at atmospheric pressure. It is quite a challenge to generate atmospheric pressure uniform glow discharge plasma, especially in air. This is because air plasma needs very high voltage for initiation of discharge. If the high voltage is used along with high current density, it leads to the formation of streamers, which is undesirable for most applications like textile treatment, etc. Researchers have tried to generate high-density plasma using a RF source, nanosecond pulsed DC source, and medium frequency AC source. However, these solutions suffer from low current discharge and low efficiency due to the addition of an external resistor to control the discharge current. Moreover, they are relatively costly and bulky. This paper presents a new power supply configuration which is very compact and generates high average density (∼0.28 W/cm²) uniform glow DBD plasma in air at atmospheric pressure. The efficiency is also higher as no external resistor is required to control the discharge current. An inherent feature of this topology is that it can drive higher current oscillations (∼50 A peak and 2-3 MHz frequency) into the plasma that damp out due to the plasma dissipation only. A newly proposed model has been used with experimental validation in this paper. Simulations and experimental validation of the proposed topology are included. Also, the application of the generated plasma for polymer film treatment is demonstrated.

Vascular endothelial growth factor: Evidence for autocrine signaling in hepatocellular carcinoma cell lines affecting invasion

BACKGROUND AND AIM

Vascular endothelial growth factor (VEGF) is a well-known pivotal regulator of tumor angiogenesis. Apart from endothelial cells, it is also expressed in nonendothelial cells, including tumor cells themselves. Hence the aim of this study was to investigate the autocrine effects of VEGF in hepatocellular carcinoma (HCC) -derived cell lines.

MATERIALS AND METHODS

Two hepatocellular carcinoma cell lines (Hep3B and HepG2) were screened for expression of VEGF by quantitative real-time polymerase chain reaction (PCR) and its receptors VEGF-R1, VEGF-R2, and neuropilin-1 expression by reverse transcriptase-PCR, respectively. Furthermore, VEGF transcript was silenced by siRNA and the effects on cell migration, viability, and proliferation were determined by the wound healing assay, MTT assay, and propidium iodide staining, respectively.

RESULTS

Both Hep3B and HepG2 cell lines expressed VEGF and all the three receptors at high levels. VEGF siRNA inhibited VEGF expression significantly in both Hep3B and HepG2 cell lines. Silencing of VEGF showed decreased migration in the Hep3B cell line. In both cell lines tested, there was decreased cell viability but no effect on cellular proliferation.

CONCLUSION

Our data indicates that autocrine signaling of VEGF through its receptors exists in HCC cell lines, which has important implications for tumor invasion, metastasis, and for designing interventional strategies.

Risk Factors for Post-Traumatic Endophthalmitis in Patients with Positive Intraocular Cultures

Purpose

To determine the risk factors for post-traumatic endophthalmitis in patients with positive intraocular culture.

Methods

An institutional-based prospective nonrandomized interventional study of patients older than 15 years who presented for primary repair of open globe injury between June 2003 and April 2005 was undertaken. The main outcomes measured were initial and final visual acuity, type of injury, presence of uveal and vitreous prolapse, time interval between injury and primary repair of the globe, length of wound, location of wound, and virulence of organism. Statistical analysis tests used were Student t-test, Fisher exact test, and chi-square test.

Results

Fifty patients were included in the study. They were divided into two groups: Group 1 (n=19) patients, who developed clinically significant endophthalmitis; and Group 2 (n=31) patients, who did not develop clinically significant endophthalmitis. Delay in primary repair more than 36 hours (p=0.042), length of wound more than 8 mm (p=0.050), and isolation of organisms like fungus (p=0.006, OR=14), Bacillus cereus (p=0.01, OR=11.25), and Pseudomonas aeruginosa (p=0.05–0.10, OR=11.3) significantly increased the risk of endophthalmitis. Mean initial and final visual acuity was better in Group 2 but was not statistically significant (p=0.21).

Conclusions

Final visual outcome in the presence of positive intraocular culture is poor. Isolation of virulent organisms, longer length of laceration, and delayed primary repair of open globe injuries have high risk of developing endophthalmitis. Prophylactic intraocular antibiotics should be considered in cases with longer length of wound and delayed primary closure.

Utilization of Preventive and Curative Services in Five Rural Blocks in Vellore, India

This health utilization survey of 720 children (age <2 y) from 5 rural blocks in Vellore district identified that 80% used government facilities for preventive care while >80% used private facilities for curative services. Only 0.7% were home deliveries, 46% reported illness in the two-week recall, and 83% sought care for these illness.

Domestic dogs as reservoir hosts for Leishmania donovani in the southernmost Western Ghats in India

The peripheral blood samples from domestic dogs (n=47) and wild rats (n=25) in the Kani Tribe settlements, located southernmost part of the Western Ghats, Thiruvananthapuram district, Kerala, India were examined for Leishmania infection. This area is known for cases of leishmaniasis with cutaneous manifestations and sandfly abundance. The tribes domesticate dogs to protect them from untoward activities of wild animals. Leishmania donovani parasite DNA was detected only from 6.4% (n=3) of the blood samples collected from the domestic dogs by amplification of the diagnostic kinetoplast mini-circle DNA and PCR-RFLP analysis of the UTR region of heat shock protein 70 (hsp70) gene. None of the blood samples collected from rats was positive. Through sequencing, L. donovani infection among dogs was confirmed. The DNA sequences generated for hsp70 were deposited with the GenBank. The GenBank accession numbers of these samples are KR905363, KR905364 and KR905365 for hsp70 genes. The results indicated that the DNA isolates from dog blood samples matched precisely with that of our earlier isolates from skin lesions of Kani tribes and also from P. argentipes vector. Thus, the role of dogs as reservoirs for L. donovani parasite in the Kani tribe settlements is confirmed.

Tracked Vehicle Performance Evaluation using Multi Body Dynamics

The objective of the study was to shorten the design cycle and evaluate the performance of infantry fighting vehicle using advanced multi body dynamics (MBD) environment before physical prototypes built. The MBD model is built with tracked vehicle module consisting of tracks (Links), sprocket, Support rollers, and hydro pneumatic suspension with suitable connections. Hull, turret are characterised by mass and inertial properties. The dynamic analysis was carried out for different field conditions i.e. trench crossing, step and ramp climbing, etc., to extract the hull forces at joints, power required to manuever, track tension forces to determine overall vehicle stability and look for possible design modifications. Recommendations were then suggested for power train, number of track segments, tensioner force, etc to ensure proper behavior during different manuevers. The MBD results are used in FEA to determine structural response in terms of stress, deformation, fatigue etc., and reflects in design modification before physical prototype made and are validated with base level analytical results.

Insecticidal Effects on the Spatial Progression of Tomato Yellow Leaf Curl Virus and Movement of Its Whitefly Vector in Tomato

Commercial management of whitefly-transmitted Tomato yellow leaf curl virus (TYLCV) typically relies on insecticide control of whitefly vectors as a first line of defense. We quantified this effect in crop tunnel studies, with validation in a tomato field setting. Tomato yellow leaf curl virus-infected and Bemisia tabaci (Gennadius)-infested source plants were planted at the beginning of tunneled rows to serve as inoculum source, so that movement of whiteflies and TYLCV symptoms could be tracked down the length of the tunnel over time. Tunnel study results showed that proximity to the source plant was a more important factor than insecticide treatments. Insecticide-treated tomato transplants did tend to suppress whitefly incidence and slowed TYLCV movement in comparison with the untreated check; however, tomato plants planted closer to the source plant had higher incidence of whiteflies and TYLCV infection, regardless of treatment. In a large tomato plot study with a controlled inoculum source, insecticide treatments significantly reduced the spread of TYLCV. When uninhibited by insecticide treatment, 80% of the TYLCV spread was restricted to <15 m from the source plant (<11 m in the validation study), with insecticide treatment generally reducing the distance and magnitude of this spread.

Three decades of managing Tomato spotted wilt virus in peanut in southeastern United States

Southeastern states namely Georgia, Florida, and Alabama produce two-thirds of the peanuts in the United States. Thrips-transmitted Tomato spotted wilt virus (TSWV), which causes spotted wilt disease, has been a major impediment to peanut production for the past three decades. The cultivars grown in the 1980s were extremely susceptible to TSWV. Early yield losses extended to tens of millions of dollars each year (up to 100% loss in many fields). This situation led to the creation of an interdisciplinary team known as "SWAT: Spotted Wilt Action Team". Initial efforts focused on risk mitigation using a combination of chemical and cultural management practices along with a strong investment in breeding programs. Beginning in the mid 1990s, cultivars with field resistance were developed and integrated with cultural and chemical management options. A Risk Mitigation Index (Peanut Rx) was made available to growers to assess risks, and provide options for mitigating risks such as planting field resistant cultivars with in-furrow insecticides, planting after peak thrips incidence, planting in twin rows, and increasing seeding rates. These efforts helped curtail losses due to spotted wilt. The Peanut Rx continues to be refined every year based on new research findings. Breeding efforts, predominantly in Georgia and Florida, continue to develop cultivars with incremental field resistance. The present-day cultivars (third-generation TSWV-resistant cultivars released after 2010) possess substantially greater field resistance than second-generation (cultivars released from 2000 to 2010) and first-generation (cultivars released from 1994 to 2000) TSWV resistant cultivars. Despite increased field resistance, these cultivars are not immune to TSWV and succumb under high thrips and TSWV pressure. Therefore, field resistant cultivars cannot serve as a 'stand-alone' option and have to be integrated with other management options. The mechanism of resistance is also unknown in field resistant cultivars. Recent research in our laboratory evaluated field resistant cultivars against thrips and TSWV. Results revealed that some resistant cultivars suppressed thrips feeding and development, and they accumulated fewer viral copies than susceptible cultivars. Transcriptomes developed with the aid of Next Generation Sequencing revealed differential gene expression patterns following TSWV infection in susceptible than field resistant cultivars. Results revealed that the upregulation of transcripts pertaining to constitutive and induced plant defense proteins in TSWV resistant cultivars was more robust over susceptible cultivars. On the flipside, the long-term effects of using such resistant cultivars on TSWV were assessed by virus population genetics studies. Initial results suggest lack of positive selection pressure on TSWV, and that the sustainable use of resistant cultivars is not threatened. Follow up research is being conducted. Improvements in TSWV management have enhanced sustainability and contributed to increased yields from <2800kg/ha before 1995 to ∼5000kg/ha in 2015.

Spectral characterization and antibacterial activity of an isolated compound from Memecylon edule leaves

Memecylon edule Roxb. (Melastamataceae family) is a small evergreen tree reported as having ethnobotanical and pharmacological properties. The present study was aimed to investigate the spectral characterization and antibacterial activity of isolated pure compound (3β-hydroxyurs-12-en-28-oic acid (ursolic acid)) from Memecylon edule leaves by performing bioassay guided isolation method. The structure derivation of isolated compound was done by different spectral studies like UV, FT-IR, LC-MS, CHNS analysis, 1D (1H, 13C and DEPT-135) and 2D-NMR (HSQC and HMBC), respectively. About 99.29% purity of the compound was found in LC analysis. 1H NMR spectrum results of compound shown 48 protons appear at different shielded region and most of the protons were present in aliphatic region. Whereas, 13C NMR spectral data resulted seven methyl carbons (CH3), nine methylene carbons (CH2), seven methine carbons (CH) and six non-hydrogenated carbons (C) which are characteristic of pentacyclic triterpene. The isolated pure compound was tested for its antibacterial properties against targeted human pathogens by performing agar well diffusion, MIC and MBC assays and the result exhibits better growth inhibitory effects against S. epidermidis and S. pneumoniae, with the MIC values of 1.56 and 3.15μg/ml. The outcome of this study suggests that the bioactive compound is used for development of plant based drugs in pharmaceutical industry for combating microbial mediated diseases.

Study design and baseline results of an open-label cluster randomized community-intervention trial to assess the effectiveness of a modified mass deworming program in reducing hookworm infection in a tribal population in southern India

Introduction

Hookworm infection is a leading cause of iron deficiency anemia and malnutrition in resource-poor settings. Periodic mass deworming with anthelminthic drugs remains the cornerstone of hookworm control efforts worldwide. Reinfection following treatment occurs, reflecting the human host's inability to acquire immunity following exposure to an untreated reservoir of infection. This cluster randomized trial will evaluate the effectiveness of a modified, population-based, mass deworming strategy in reducing hookworm infection in an endemic southern Indian population.

Methods

Forty five tribal villages were randomized into three groups: one received annual treatment; the second received two rounds of treatment at 1-month intervals; and the third received four rounds of treatment – two rounds 1 month apart at the beginning, followed by another two after 6 months. Stool samples collected through cross-sectional parasitological surveys pre- and post-intervention, and at 3-monthly intervals for a period of 1 year were tested for presence of hookworm ova. Long-term effectiveness of treatment will be assessed through another survey conducted 2 years after the last treatment cycle.

Results

From a population of 11,857 individuals, 8681 (73.2%) were found to be eligible and consented to participate, out-migration being the primary reason for non-participation. Baseline stool samples were obtained from 2082 participants, with 18.5% having hookworm infection, although majority were low intensity infections (<2000 eggs per gram of feces).

Discussion

This study will help identify the optimal mass deworming strategy that can achieve the greatest impact in the shortest period of time, particularly in settings where long-term program sustainability is a challenge.

Direct Medical Costs in Children with Rotavirus and Non-rotavirus Diarrhea Admitted to a Pediatric Intensive Care Unit and High Dependency Unit in Delhi

OBJECTIVE

To estimate direct medical costs of diarrheal hospitalization of children <5 years admitted in pediatric intensive care unit (PICU) or high dependency unit (HDU).

METHODS

Analysis of medical records and hospital bills of 84 children during two time frames, 2005-08 and 2012-14.

RESULTS

Direct medical costs in PICU increased from INR 17,941 to INR 50,663 per child for rotavirus diarrhea and INR 11,614 to INR 27,106 for non-rotavirus diarrhea, and in HDU from approximately INR 5,800 to INR 10,500 per child for all-cause diarrhea between the two time frames.

CONCLUSIONS

Costs of PICU and HDU care are high and should be included in cost-effectiveness analysis of vaccination.

Racecadotril in the Management of Rotavirus and Non-rotavirus Diarrhea in Under-five Children: Two Randomized, Double-blind, Placebo-controlled Trials

OBJECTIVE

To study the effect of racecadotril on reduction in the duration of acute rotavirus and non-rotavirus diarrhea.

DESIGN

Two randomized double-blind placebo-controlled trials.

SETTING

Community-based trial in an urban area in Vellore, hospital-based trial at a secondary hospital in Vellore.

PARTICIPANTS

199 and 130 3-59 month old children in the community- and hospital-based trials, respectively.

METHODS

Racecadotril (1.5 mg/kg/dose, thrice a day for three days) or placebo were given to manage acute diarrhea in both trials.

MAIN OUTCOME MEASURE

Median duration of diarrhea.

RESULTS

Among 124 children completing the hospital trial, the median duration of diarrhea was 25 h in both arms (P=0.5); median total stool weight was 74 g/kg and 53.5 g/kg in racecadotril group and placebo group, respectively (P=0.4); and average fluid intake per day was 3.6 mL/kg/h and 3mL/kg/h in racecadotril and placebo arms, respectively (P=0.3). Among rotavirus-positive children, median duration of diarrhea was 26.9 h and 30.2 h in racecadotril and placebo arms, respectively (P=0.7). In the community, 196 completed the trial, the median duration of diarrhea was 2 days for both arms (P=0.8) and rotavirus positive children had similar outcomes with median diarrheal duration of 3 d in both arms (P=0.4).

CONCLUSIONS

Treatment with racecadotril did not reduce diarrheal duration, stool volume or the requirement for fluid replacement in children with acute gastroenteritis, both with and without rotavirus infection.

Direct and Indirect Costs of Pediatric Gastroenteritis in Vellore, India

OBJECTIVE

To determine costs of pediatric gastroenteritis in out-patient and in-patient facilities.

METHODS

Cross-sectional survey of children with acute gastroenteritis attending out-patient clinic (n=30) or admitted in the ward (n=30) for management in the Christian Medical College, Vellore, India from July-September 2014 to estimate direct (drugs, tests, consultation/hospitalization) and indirect (travel, food, lost wages) costs associated with the episode.

RESULTS

Median direct and indirect costs were Rs 590 and Rs 190 for out-patient management and Rs 7258 and Rs. 610 for hospitalization, constituting 1.1% and 11% of median annual household income, respectively.

CONCLUSIONS

Escalating healthcare costs need tracking for evaluation of interventions.