Gut bacteria of cockroaches are a potential source of antibacterial compound(s)

Here, we hypothesized that the microbial gut flora of animals/pests living in polluted environments, produce substances to thwart bacterial infections. The overall aim of this study was to source microbes inhabiting unusual environmental niches for potential antimicrobial activity. Two cockroach species, Gromphadorhina portentosa (Madagascar) and Blaptica dubia (Dubia) were selected. The gut bacteria from these species were isolated and grown in RPMI 1640 and conditioned media were prepared. Conditioned media were tested against a panel of Gram‐positive (Methicillin‐resistant Staphylococcus aureus, Streptococcus pyogenes, Bacillus cereus) and Gram‐negative (Escherichia coli K1, Salmonella enterica, Serratia marcescens, Pseudomonas aeruginosa, Klebsiella pneumoniae) bacteria, as well as the protist pathogen, Acanthamoeba castellanii. The results revealed that the gut bacteria of cockroaches produce active molecule(s) with potent antibacterial properties, as well as exhibit antiamoebic effects. However, heat‐inactivation at 95°C for 10 min had no effect on conditioned media‐mediated antibacterial and antiamoebic properties. These results suggest that bacteria from novel sources i.e. from the cockroach's gut produce molecules with bactericidal as well as amoebicidal properties that can ultimately lead to the development of therapeutic drugs.

Significance and Impact of the Study

The bacteria isolated from unusual dwellings such as the cockroaches' gut are a useful source of antibacterial and antiamoebal molecules. These are remarkable findings that will open several avenues in our search for novel antimicrobials from unique sources. Furthermore studies will lead to the identification of molecules to develop future antibacterials from insects.     

Phaseolus lunatus,a New Host of Xanthomonas axonopodis pv. phaseoli in Iran

Common bacterial blight caused by Xanthomonas axonopodis pv. phaseoli (Xap) is one of the most destructive diseases limiting the production of common bean (Phaseolus vulgaris) in Iran. The disease has previously been described on common bean and mung bean from several regions of Iran, including the central plain and south‐western provinces. In this study, lima bean (Phaseolus lunatus cv. Christmas) plants are being reported as a new natural host of Xap in East Azerbaijan and West Azerbaijan Provinces, northwestern Iran. Disease symptoms consisted initially of water‐soaked spots that progressed to irregular necrotic lesions with chlorotic margins. Infection was observed to affect up to 40% of plants in the field. Identification of the pathogen was based on the biochemical and molecular characteristics, as well as the pathogenicity tests. To our knowledge, this is the first report of X. axonopodis pv. phaseoli causing common bacterial blight on lima bean plants in Iran.     

The role of selenium in amelioration of heat-induced oxidative damage in cucumber under high temperature stress

High temperature is an environmental stress which destroys agricultural crops and inhibits their growth and productivity. The aim of current investigation was to examine the role of selenium (Se) on cucumber (Cucumis sativus L.) cv. Sahil plant growth, physio-biochemical and yield attributes under heat stress (HS) in controlled conditions. Plants were grown under normal temperature (NT; 28/18 °C day/night) from sowing to 32 days after sowing (DAS). All plants were foliar-sprayed with Se (8 µM) at flower-initiation stage (32-DAS) and heat stress (HS; 40/30 °C day/night) was induced from 35-DAS to entire duration of the experiment (75-DAS). Data regarding growth, physio-biochemical and yield traits were measured. Heat stress decreased growth traits, total chlorophyll contents, chlorophyll fluorescence parameters, photosynthesis (Pn), stomatal conductance (g _s), transpiration rate (E), antioxidant enzyme activities, membrane stability index (MSI) and yield-related attributes, while increased intercellular CO₂ (Ci), ROS production, lipid peroxidation (LPO), non-photochemical quenching (NPQ) and compatible solutes. Exogenous application of Se mitigated HS-induced injurious effects by improving growth components, Pn, g _s, E, chlorophyll content, chlorophyll fluorescence parameters, antioxidant enzyme activities, level of osmolytes, MSI and yield attributes and reducing ROS, LPO and NPQ. Selenium reversed heat-induced oxidative damage by strengthening antioxidative mechanism, which resulted in higher scavenging of ROS, thereby minimizing LPO. It is suggested that Se-induced improvement in Pn, growth and productivity associated traits under HS is linked with enhanced antioxidant activities and osmolytes accumulation. In addition, Se applied at flower initiation is highly effective in alleviating heat damage in cucumber.     

The synergistic effects of sucrose and plant growth regulators on morphogenesis and evaluation of antioxidant activities in regenerated tissues of <Emphasis Type="Italic">Caralluma tuberculata</Emphasis>

Caralluma tuberculata (C. tuberculata) is a very important medicinal plant with a range of anti-diabetic and weight reduction properties. This high-valued medicinal plant is nowadays considered as endangered due to its unsustainable elimination from wild habitats. There is lack of research efforts on its propagation to overcome escalating demand. In this research study, an effort has been made to optimize protocol for large-scale mass propagation and production of natural antioxidants. Highest callogenic response (87.2 %) was observed from shoot tip explants on Murashige and Skoog (MS) medium containing 30 g l^?1 sucrose and combination of 2, 4-D (2.0 mg l^?1) and BA (1.0 mg l^?1). During shoot morphogenesis, 50 g l^?1 sucrose along with BA (2.0 mg l^?1) and GA₃ (1.0 mg l^?1) enhanced shoot regeneration (91.3 %), mean shoot length (2.6 cm) and shoots per explant (24.5) as compared to control. The combination of IBA and IAA (2.0 mg l^?1) was found optimum for root induction (74.98 %), mean root length (4.1 cm) and roots per shoot (6.9) as compared to control. The plantlets were successfully acclimatized in plastic cups and various tissues were investigated for accumulation of antioxidant secondary metabolites including phenolics, flavonoids, stress enzymes and antioxidant activities. The superoxide dismutase enzyme was higher in shoots; protein content was higher in callus cultures; phenolics, DPPH and protease activity were higher in plantlets, while flavonoids, peroxidase, reducing power and total antioxidant activities were higher in wild plants. This simple protocol is very useful for commercial production of consistent plantlets and metabolites of interest.     

<Emphasis Type="Italic">Chlamydomonas reinhardtii</Emphasis> chloroplasts express an orally immunogenic protein targeting the p210 epitope implicated in atherosclerosis immunotherapies

Key message

An algae-based vaccine model against atherosclerosis was developed with positive findings in terms of antigen yield and immunogenicity in mouse.

Abstract

Several immunotherapies against atherosclerosis have been evaluated at the preclinical level thus far, with some of them currently under evaluation in clinical trials. In particular, the p210 epitope from ApoB100 is known to elicit atheroprotective responses. Considering that Chlamydomonas reinhardtii is an attractive host for the production and delivery of subunit vaccines, in this study a chimeric protein consisting of the B subunit of the cholera toxin and the p210 epitope from ApoB100 (CTB:p210) has been expressed in C. reinhardtii chloroplast as an attempt to establish an oral vaccine candidate against atherosclerosis. The Chlamydomonas-made CTB:p210 protein was successfully expressed at levels of up to 60 µg per g of fresh weight biomass. The antigenic activity of the CTB and the p210 moiety was preserved in the CTB:p210 chimera. Moreover the algae-made CTB:p210 showed an immunogenic activity, when orally administered to BALB/c mice, as evidenced the presence of anti-p210 serum antibodies in mice treated with the algae-derived CTB:p210. The antibody response lasts for at least 80 days after the last boost. This experimental model is proposed as a convenient tool in the development of low cost atherosclerosis vaccines of easy compliance and friendly delivery. Further studies will determine the therapeutic potential of this algae-made vaccine in atherosclerosis animal models.

     

Elevated CO<Subscript>2</Subscript> influences host plant defense response in chickpea against <Emphasis Type="Italic">Helicoverpa armigera</Emphasis>

Global atmospheric concentration of CO₂ is likely to increase from 350 to 750 ppm over the next 100 years. The present studies were undertaken to understand the effects of elevated CO₂ on enzymatic activity and secondary metabolites in chickpea in relation to expression of resistance to pod borer, Helicoverpa armigera. Fifteen-day-old chickpea plants [ICCL 86111—resistant and JG 11—commercial cultivar] grown in the greenhouse were transferred to open-top chambers (OTC) and kept under 350, 550 and 750 ppm of CO₂. Twenty neonates of H. armigera were released on each plant at 7 days after shifting the pots to the OTCs. Un-infested plants were maintained as controls. After 7 days of infestation, the activities of defensive enzymes [peroxidase (POD), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL)] and amounts of total phenols and condensed tannins increased with an increase in CO₂ concentration in chickpea. The nitrogen balance index was greater in plants kept at 350 ppm CO₂ than in plants kept under ambient conditions. The H. armigera-infested plants had higher H₂O₂ content; amounts of oxalic and malic acids were greater at 750 ppm CO₂ than at 350 ppm CO₂. Plant damage was greater at 350 ppm than at 550 and 750 ppm CO₂. This information will be useful for understanding effects of increased levels of CO₂ on expression of resistance to insect pests to develop strategies to mitigate the effects of climate change.     

Myosin light-chain expression during avian muscle development

Monoclonal antibodies to adult chicken myosin light chains were generated and used to quantitate the types of myosin light-chain (MLC) isoforms expressed during development of the pectoralis major (PM), anterior latissimus dorsi (ALD), and medial adductor (MA) muscles of the chicken. These are muscles which, in the adult, are composed predominantly of fast, slow, and a mixture of fiber types, respectively. Three distinct phases of MLC expression characterized the development of the PM and MA muscles. The first identifiable pase occurred during the period of 5-7 d of incubation in ovo. Extracts of muscles from the pectoral region (which included the presumptive PM muscle) contained only fast MLC isoforms. This period of exclusive fast light-chain synthesis was followed by a phase (8- 12 d of incubation in ovo) in which coexpression of both fast and slow MLC isoforms was apparent in both PM and MA muscles. During the period, the composition of both fast and slow MLC isoforms in the PM and MA muscles was identical. Beginning at day 12 in ovo, the ALD was also subjected to immunochemical analyses. The proportion of fast and slow MLCs in this muscle at day 12 was similar to that present in the other muscles studied. The third development phase of MLC expression began at approximately 12 d of incubation in ovo and encompassed the transition in MLC composition to the isoform patterns incubation in ovo and encompassed the transition in MLC composition to the isoform patterns typical of adult muscle. During this period, the relative proportion of slow MLC rose in both the MA and ALD and fell in the PM. By day 16, the third fast light chain, LC(3f), was apparent in extracts of both the PM and MA. These results show that there is a developmental progression in the expression of MLC in the two avian muscles studied from day 5 in ovo; first, only fast MLCs are accumulated, then both fast and slow MLC isoforms are expressed. Only during the latter third of development in ovo is the final MLC isoform pattern characteristic of a particular muscle type expressed.     

Contraceptive use patterns in Matlab, Bangladesh: insights from a 1984 survey

An experimental maternal and child health and family planning programme has been in existence in Matlab for almost 10 years. During this time the project has achieved remarkable success in the area of family planning. Based upon a 1984 survey, this study examines the pattern of contraceptive use in the Matlab treatment area, and contrasts it with the regular government programme in the neighbouring comparison area. Important differences between the two areas are observed, with the treatment area characterized by substantially higher levels of current contraceptive use, greater reliance upon temporary methods for birth spacing and, among acceptors of sterilization, more prior experimentation with other methods. In the comparison area lower rates of contraceptive use are observed, with heavy reliance upon tubectomy for limiting family size. The findings suggest that an intensive and innovative family planning programme in rural Bangladesh can achieve success not only in terms of contraceptive prevalence, but can also attract users interested in child spacing and others wanting to limit their family size, by offering the widest range of contraceptive methods.     

Feeding by sugarcane aphid,Melanaphis sacchari,on sugarcane cultivars with differential susceptibility and potential mechanism of resistance

Feeding behavior of Melanaphis sacchari Zehntner (Hemiptera: Aphididae) was studied on sugarcane, Saccharum spp. (Poaceae), cultivars HoCP 91‐555 (resistant), LCP 85‐384 (moderately resistant), and L 97‐128 (susceptible) using the electrical penetration graph (EPG) technique. Constitutive concentrations of total phenolics and available carbohydrates, water potential at the whole‐leaf tissue level, and free amino acids (FAAs) in phloem sap extracts, and in honeydew produced by aphids fed on L 97‐128 and HoCP 91‐555 were determined. Cultivar did not influence time for M. sacchari to access phloem sieve elements. Total time in sieve elements was ca. two‐fold greater on L 97‐128 than on HoCP 91‐555, whereas it did not differ from LCP 85‐384 in either cultivar. The mean duration of individual events associated with phloem sap ingestion was ca. 50% shorter on both HoCP 91‐555 and LCP 85‐384 than on L 97‐128. Although cultivar effects were not detected for levels of total phenolics, available carbohydrates, and water potential, two free essential amino acids, histidine and arginine, were absent from phloem sap in HoCP 91‐555. Two free essential amino acids, leucine and isoleucine, and two free non‐essential amino acids, tyrosine and proline, were absent from honeydew of aphids fed on HoCP 91‐555. These results suggest that despite apparent biosynthesis of some FAAs, the absence of important FAAs in the phloem sap of HoCP 91‐555 and the inability of M. sacchari and its endosymbionts (e.g., Buchnera) to derive specific free essential and non‐essential amino acids from other ingested molecules, possibly along with other unidentified factors, underlie the pest's decreased phloem sap ingestion and consequently reduced growth potential on HoCP 91‐555.     

Studies on the interaction between nanodiamond and human hemoglobin by surface tension measurement and spectroscopy methods

In this study, a novel method to probe molecular interactions and binding of human hemoglobin (Hb) with nanodiamond (ND) was introduced based on the surface tension measurement. This method complements conventional techniques, which are basically done by zeta potential and dynamic light scattering (DLS) measurements, near and far circular dichroism (CD) spectroscopy, intrinsic and extrinsic fluorescence spectroscopy. Addition of ND to Hb solution increased the surface tension value of Hb–ND complex relative to those of Hb and ND molecules. The zeta potential values reveled that Hb and ND provide identical charge distribution at pH 7.5. DLS measurements demonstrated that Hb, ND, and ND–Hb complex have hydrodynamic radiuses of 98.37 ± 4.57, 122.07 ± 7.88 nm and 62.27 ± 3.70 at pH of 7.5 respectively. Far and near UV-CD results indicated the loss of α-helix structure and conformational changes of Hb, respectively. Intrinsic fluorescence data demonstrated that the fluorescence quenching of Hb by ND was the result of the static quenching. The hydrophobic interaction plays a pivotal role in the interaction of ND with Hb. Fluorescence intensity changes over time revealed conformational change of Hb continues after the mixing of the components (Hb–ND) till 15 min, which is indicative of the denaturation of the Hb relative to the protein control. Extrinsic fluorescence data showed a considerable enhancement of the ANS fluorescence intensity of Hb–ND system relative to the Hb till 60 nM of ND, likely persuaded by greater exposure of nonpolar residues of Hb hydrophobic pocket. The remarkable decrease in T_m value of Hb in Hb–ND complex exhibits interaction of Hb with ND conducts to conformational changes of Hb. This study offers consequential discrimination into the interaction of ND with proteins, which may be of significance for further appeal of these nanoparticles in biotechnology prosecution.