Strong larvicidal potential of Artemisia annua leaf extract against malaria (Anopheles stephensi Liston) and dengue (Aedes aegypti L.) vectors and bioassay-driven isolation of the marker compounds

Malaria and dengue are the two most important vector-borne human diseases caused by mosquito vectors Anopheles stephensi and Aedes aegypti, respectively. Of the various strategies adopted for eliminating these diseases, controlling of vectors through herbs has been reckoned as one of the important measures for preventing their resurgence. Artemisia annua leaf chloroform extract when tried against larvae of A. stephensi and A. aegypti has shown a strong larvicidal activity against both of these vectors, their respective LC50 and LC90 values being 0.84 and 4.91 ppm for A. stephensi and 0.67 and 5.84 ppm for A. aegypti. The crude extract when separated through column chromatography using petroleum ether-ethyl acetate gradient (0–100 %) yielded 76 fractions which were pooled into three different active fractions A, B and C on the basis of same or nearly similar R _f values. The aforesaid pooled fractions when assayed against the larvae of A. stephensi too reported a strong larvicidal activity. The respective marker compound purified from the individual fractions A, B and C, were Artemisinin, Arteannuin B and Artemisinic acid, as confirmed and characterized through FT-IR and NMR. This is our first report of strong mortality of A. annua leaf chloroform extract against vectors of two deadly diseases. This technology can be scaled up for commercial exploitation.     

Behavioral and electrophysiological responses of Aedes albopictus to certain acids and alcohols present in human skin emanations

Human skin emanations attract hungry female mosquitoes toward their host for blood feeding. In this study, we report the flight orientation and electroantennogram response of Aedes albopictus females to certain unsaturated acids and alcohols found in human skin. In the Y-tube olfactometer, odors of lactic acid and 2-methyl-3-pentanol attracted 54–65 % of Ae. albopictus females at all doses in a dose-dependent manner. However, at the highest dose (10^?2 g), the acids repelled 40–45 % females. Attractancy (ca. 62–68 %) at lower doses and repellency (ca. 30–45 %) at higher doses were recorded for 3-methyl-3-pentanol and 1-octen-3-ol, while 5-hexen-1-ol, cis-2-hexen-1-ol, and trans 2-hexen-1-ol odor repelled ca. 55–65 % of Ae. albopictus females at all doses. Antenna of female Ae. albopictus exhibited a dose-dependent EAG response up to 10^?3 g of l-lactic acid, trans-2-methyl-2-pentenoic acid, 2-octenoic acid, trans-2-hexen-1-ol and 1-octen-3-ol stimulations; however, the highest dose (10^?2 g) caused a little decline in the EAG response. EAG response of 9–10-fold was elicited by lactic acid, 2-octenoic acid, trans-2-hexenoic acid, and 3-methyl-3-pentanol, while cis-2-hexen-1-ol and trans-2-methyl pentenoic acid elicited 1–5-fold responses compared to solvent control. A blend of attractive compounds could be utilized in odor-baited trap for surveillance and repellent molecules with suitable formulation could be used to reduce the biting menace of mosquitoes.     

Outbreak of Streptococcus pyogenes emm type 58 in a high dependency unit of a level-1 trauma center of India

Background and Aims:

Group A Streptococcus (GAS) can cause illnesses ranging from self-limited to severe, life-threatening, invasive infections. The objective of the following study was to investigate a suspected Streptococcus pyogenes outbreak in a high dependency unit (HDU) of our trauma center.

Materials and Methods:

All the isolates of beta hemolytic Streptococci were identified by standard microbiological methods, Vitek 2 system and latex agglutination tests. Antimicrobial susceptibility testing was performed as recommended by Clinical Laboratory Standards Institute. Exotoxin genes, including speA, speB, speC, speF, smeZ, ssa, speG, speH, speJ, speL, speM and speI were detected by polymerase chain reaction (PCR). The emm types of isolates of S. pyogenes were determined by sequencing the variable 5’ end of emm gene after amplification by PCR.

Results:

In a 28 bedded poly-trauma ward with a four bedded HDU three out of four patients developed S. pyogenes emm type 58 infection. The strain was macrolide and tetracycline resistant and produced the Streptococcal pyrogenic exotoxins speB, speC, speG, speF and smeZ. Surveillance sampling was done for investigation from patients, health-care workers and environmental samples.

Conclusion:

An outbreak of GAS infections was established caused by the uncommonly reported emm type 58. The outbreak was controlled by prompt treatment, intensive surveillance, feedback and training.     

Fractional exhaled nitric oxide in children with acute exacerbation of asthma

Objective

To determine whether fractional exhaled nitric oxide (FENO) has a utility as a diagnostic or predictive maker in acute exacerbations of asthma in children.

Design

Analysis of data collected in a pediatric asthma cohort.

Setting

Pediatric Chest Clinic of a tertiary care hospital

Methods

A cohort of children with asthma was followed up every 3 months in addition to any acute exacerbation visits. Pulmonary function tests (PFT) and FENO were obtained at all visits. We compared the FENO values during acute exacerbations with those at baseline and those during the follow up.

Results

243 asthmatic children were enrolled from August 2009 to December 2011 [mean (SD) follow up — 434 (227) days]. FENO during acute exacerbations was not different from FENO during follow up; however, FENO was significantly higher than personal best FENO during follow up (P < 0.0001). FENO during acute exacerbation did not correlate with the severity of acute exacerbation (P=0.29). The receiver operating characteristics curve for FENO as a marker for acute exacerbation had an area under the curve of 0.59. Cut-off of 20 ppb had a poor sensitivity (44%) and specificity (68.7%) for acute exacerbation.

Conclusions

FENO levels during acute exacerbation increase from their personal best levels. However, no particular cut off could be identified that could help in either diagnosing acute exacerbation or predicting its severity.     

From the Cover: Defense mutualisms enhance plant diversification

The ability of plants to form mutualistic relationships with animal defenders has long been suspected to influence their evolutionary success, both by decreasing extinction risk and by increasing opportunity for speciation through an expanded realized niche. Nonetheless, the hypothesis that defense mutualisms consistently enhance plant diversification across lineages has not been well tested due to a lack of phenotypic and phylogenetic information. Using a global analysis, we show that the >100 vascular plant families in which species have evolved extrafloral nectaries (EFNs), sugar-secreting organs that recruit arthropod mutualists, have twofold higher diversification rates than families that lack species with EFNs. Zooming in on six distantly related plant clades, trait-dependent diversification models confirmed the tendency for lineages with EFNs to display increased rates of diversification. These results were consistent across methodological approaches. Inference using reversible-jump Markov chain Monte Carlo (MCMC) to model the placement and number of rate shifts revealed that high net diversification rates in EFN clades were driven by an increased number of positive rate shifts following EFN evolution compared with sister clades, suggesting that EFNs may be indirect facilitators of diversification. Our replicated analysis indicates that defense mutualisms put lineages on a path toward increased diversification rates within and between clades, and is concordant with the hypothesis that mutualistic interactions with animals can have an impact on deep macroevolutionary patterns and enhance plant diversity.Ever since the key innovation hypothesis was first proposed in the 1940s (1, 2), the origination of novel traits has been a popular yet controversial explanation for the exceptional disparity in species richness observed across clades in the tree of life. Despite decades of research linking traits to diversification, we have remarkably few examples of traits that have been convincingly demonstrated to spur diversification repeatedly across independent, distantly related groups. Notable exceptions include a number of ecologically important traits mediating interactions between plants and animals (3–6), suggesting that these interactions may be particularly important drivers of macroevolutionary patterns. Here, we test the hypothesis that plant defense mutualisms, a widespread and classically studied ecological interaction whereby plants provide food rewards to arthropod bodyguards in return for protection against natural enemies (7), increase the evolutionary diversification rate of the plant lineages that participate in them. The morphological traits that mediate defense mutualisms represent well-studied examples of characters hypothesized to expand a plant’s niche via interactions with mutualists and influence species success in various environmental contexts (8). Although the costs and benefits of participating in defense mutualisms are well studied (9), the hypothesis that the ecological impact of defense mutualisms leaves a predictable macroevolutionary signature, increasing lineage diversification within and among clades of plants, has only been examined in a single genus (10).Defense mutualisms may have an impact on plant speciation and extinction rates via several mechanisms. Unlike the evolution of traits related to reproduction, which, more intuitively, could have an impact on lineage diversification (e.g., refs. 5, 11), the direct mechanism by which defense mutualisms are hypothesized to influence diversification is less obvious. One direct mechanism is a decreased incidence of damage and disease due to an enhanced defensive repertoire, which may allow for increased population sizes and, in turn, lower extinction rates (6). Additionally, by expanding the realized niche of a plant (12), defense mutualisms may broaden the range of habitats a plant can occupy (10), thereby increasing instances of allopatric speciation.However, in addition to these direct mechanisms, the evolution of mutualistic traits may facilitate diversification indirectly. First, if niche expansion results in the successful occupation of more environments, mutualistic traits may increase the probability a lineage will encounter conditions ripe with ecological opportunity (e.g., new adaptive zones), which, in turn, will drive increases in diversification. In other words, the evolution of a trait may enable subsequent diversification via increasing exposure to new environments, some of which will harbor external drivers of radiation, such as the uplift of a mountain range or unoccupied niches. Second, the evolution of defense mutualisms may free up resources for the plant, and thereby facilitate the evolution of other innovative traits that subsequently enhance diversification. These indirect effects need not be contingent on the existence of the direct effects mentioned above, and represent a largely overlooked hypothesis concerning how traits can affect diversification (13–15).We suggest that indirect impacts of trait evolution on diversification should be reflected in a phylogenetic pattern in which the origination of a trait is followed by an increased probability of subsequent, downstream rate shifts relative to clades that lack the trait (Fig. 1). Because the indirect effect of the trait is contingent upon additional conditions (e.g., ecological opportunity, the evolution of another trait), there may be a substantial lag between the origin of the trait and rate shifts. Alternatively, a direct effect of the trait on the diversification rate is consistent with a pattern whereby a sustained rate shift occurs concomitantly with, or on the same branch as, the origin of the trait on the phylogeny (Fig. 1). Direct and indirect patterns are not mutually exclusive, and both patterns may be detectable on a single phylogeny (Fig. 1).Open in a separate windowFig. 1.A conceptualization of phylogenetic patterns consistent with direct or indirect effects of EFNs (or any trait) on lineage diversification. A net change in diversification may be due to direct or indirect mechanisms. In the Upper Right, a rate shift occurs concomitantly with the origin of EFNs, consistent with a direct effect. If one or more shifts occur with some delay (Lower), this is consistent with a hypothesis that a trait has an indirect or context-dependent effect on diversification rates.We focus on the macroevolutionary consequences of the repeated origination of extrafloral nectaries (EFNs), nectar-secreting glands found on nonfloral plant tissues that provide food for a wide array of beneficial arthropod bodyguards (16). EFNs are well studied ecologically, and their only known function is defense against herbivores and microbial pathogens by attracting natural enemies (17). Such features have evolved hundreds of times and occur in about a quarter of all vascular plant families (18). Here, we first ask whether, across all vascular plants, families containing species with EFNs are associated with higher diversification rates than families without EFNs. We then focus in on the phylogenetic history and evolution of EFNs in six distantly related plant clades to evaluate whether EFNs are linked, directly or indirectly, to increased lineage diversification rates. As such, this study represents a replicated, multiscale test of the macroevolutionary consequences of a convergently evolved and ecologically important mutualistic trait.     

Pediatric Cutaneous Leishmaniasis in an Endemic Region in India

Cutaneous leishmaniasis (CL) is endemic in the Bikaner region situated in the Thar Desert of Rajasthan, India. This study describes clinicoepidemiological data of pediatric CL in pre-school children (0–5 years of age) from this region during 2001–2012. In total, 151 patients with 217 lesions were reported during the study period. The mean age of the study group was 3.29 ± 1.43 years (0.25–5 years), with many (41.7%) cases being in the age group of 2–4 years. Face was the most common site involved, and morphologically, the lesions were either plaque type or papulonodular. Smear for parasitologic examination was positive in 84 (70%) of 120 cases, and histopathologic examination confirmed CL in 10 (55.55%) of 18 cases. Parasite species identification conducted for 13 randomly selected patients by polymerase chain reaction identified Leishmania tropica as the causative species. Intralesional sodium stibogluconate was the most commonly used treatment and found to be well-tolerated. Other therapies that were effective included oral rifampicin, oral dapsone, radiofrequency heat therapy (RFHT), and combinations of the three therapies.     

Aneurysmally dilated major aorto-pulmonary collateral in tetralogy of Fallot

Haemodynamically significant systemic-to-pulmonary artery collaterals may present as a cause of cardiorespiratory compromise in tetralogy of Fallot (TOF) with pulmonary atresia. We present here a case of TOF with pulmonary atresia with aneurysmally dilated aorto-pulmonary collateral causing compression over trachea, presenting as dry irritating cough who died suddenly with haemoptysis probably due to rupture of hypertrophied bronchial collaterals or direct erosion of large major aorto-pulmonary collateral arteries (MAPCA) into the respiratory tract.