Showed Growth Reduction Research Articles

6'-O-Caffeoylarbutin from Quezui Tea: A Highly Effective and Safe Tyrosinase Inhibitor.

Tyrosinase is vital in fruit and vegetable browning and melanin synthesis, crucial for food preservation and pharmaceuticals. We investigated 6'-O-caffeoylarbutin's inhibition, safety, and preservation on tyrosinase. Using HPLC, we analyzed its effect on mushroom tyrosinase and confirmed reversible competitive inhibition. UV_vis and fluorescence spectroscopy revealed a stable complex formation with specific binding, causing enzyme conformational changes. Molecular docking and simulations highlighted strong binding, enabled by hydrogen bonds and hydrophobic interactions. Cellular tests showed growth reduction of A375 cells with mild HaCaT cell toxicity, indicating favorable safety. Animal experiments demonstrated slight toxicity within safe doses. Preservation trials on apple juice showcased 6'-O-caffeoylarbutin's potential in reducing browning. In essence, this study reveals intricate mechanisms and applications of 6'-O-caffeoylarbutin as an effective tyrosinase inhibitor, emphasizing its importance in food preservation and pharmaceuticals. Our research enhances understanding in this field, laying a solid foundation for future exploration.

Antimicrobial Property of Photocatalytic Nanoparticles-Coated Personal Protective Equipment (PPE) on Bacteria and Fungi

Photocatalytic nanoparticles are new applications that can be used as coatings on surfaces through a photocatalytic process that reacts in the presence of chemical catalysts and light. The resulting reactive oxygen species (ROS) would damage pathogenic components and result in antimicrobial effects. This study was conducted to evaluate the antimicrobial properties of photocatalytic nanoparticles on personal protective equipment (PPE), namely surgical gowns and masks. Antimicrobial testing of photocatalytic nanoparticles against PPE inoculated with pathogens was carried out. The growth log reduction of isolates tested on the photocatalytic nanoparticles-coated PPE showed 100% with growth reduction exceeding 4 log against Escherichia coli ATCC 25922 as well as Staphylococcus aureus ATCC 25923 but less than 50% reduction against Candida albicans ATCC 10231. For 20 h incubation periods, both bacteria showed growth reduction of at least 4 log with 99.99% of reduction. The 5 and 20 times washing effects showed an overall reduction of 99.99%-100% against both bacteria but less than 99.99% against C. albicans. Photocatalytic nanocoating produces an antimicrobial effect that helps to kill the tested pathogens and reduce the attachment of bacteria but not fungi, on the surface of PPE. This nanoparticle is capable of continuous self-disinfection to reduce the number of pathogens. The number of washing cycle also does not affect its function to reduce the number of pathogens.

Urban environment, drought events and climate change strongly affect the growth of common urban tree species in a temperate city

Trees’ ecosystem services help reducing the urban heat island intensity, but are most effective when trees are big and healthy. During the last decades, the frequency of heat waves and drought events in Central Europe has increased, exposing urban trees to even greater stress under already challenging urban growth conditions. To understand the extent to which the urban environment affects tree growth and how trees respond to drought, dendrochronological analyses were conducted on 176 urban trees of six commonly planted tree species: Tilia cordata, Acer platanoides, Robinia pseudoacacia, Platanus x acerifolia, Fagus sylvatica and Quercus robur growing within the temperate city of Munich, Germany. The impacts of climate change were studied comparing tree growth between the periods 1980–1999 and 2000–2019, as well as the effect of the urban heat island intensity, comparing urban and suburban zones. Additionally, a drought-tolerance analysis was conducted to investigate the recovery following different dry years. Species-specific trends showed the highest average basal area increment (BAI) for P. x acerifolia (44.9 cm²/year) and the lowest for T. cordata (18.4 cm²/year). In terms of the urbanisation impact on growth, significantly higher BAI was recorded for A. platanoides and T. cordata in the suburban areas, in contrast to F. sylvatica. Analysing the complete sample, the results showed growth reduction since the year 2000 (−28%). Higher drought tolerance was found for R. pseudoacacia, P. x acerifolia and Q. robur. Accumulated drought stress showed significant negative responses for A. platanoides and T. cordata. With the predicted climate change scenarios, the present study can deepen the knowledge about drought tolerance of urban trees in temperate climate and improve species selection. In particular, R. pseudoacacia and P. x acerifolia could be further planted in cities as were less affected by high urbanisation degree and grew the most despite drought and climate change conditions.

Involvement of VIVID in white light-responsive pigmentation, sexual development and sterigmatocystin biosynthesis in the filamentous fungus Podospora anserina.

Light serves as a source of information and regulates diverse physiological processes in living organisms. Fungi perceive and respond to light through a complex photosensory system. Fungi have evolved the desensitization mechanism to adapt to the changing light signal in a natural environment. White light exerts multiple essential impacts on the model filamentous fungus Podospora anserina. However, the light sensing and response in this species has not been investigated. In this study, we demonstrated that the loss of function of the light desensitization protein VIVID (VVD) in P. anserina triggered exacerbated light responses and therefore led to drastic morphological and physiological changes. The white light-sensitive mutant Δvvd showed growth reduction, spermatia overproduction, enhanced hyphae pigmentation and reduced oxidative stress tolerance. We observed the decreased expression level of sterigmatocystin gene cluster by transcriptome analysis and finally detected the reduced production of sterigmatocystin in Δvvd in response to white light. Our data indicate that VVD acts as a repressor of white collar complex. This study exhibits a vital role of VVD in governing white light-responsive gene expression and secondary metabolite production and contributes to a better understanding of the photoreceptor VVD in P. anserina.

Cultivar-Specific Oxidative Modification of Proteins, Proteolytic Activity and Alterations in Proteomes of Rice Seedlings to Simultaneous Water Deficit and Aluminum Toxicity

Water deficit (WD) and aluminum toxicity (Al) are two key constraints to crop production, especially in upland acid soils. We examined the combined effects of the two stresses in comparison to individual stresses in the seedlings of rice (Oryza sativa L.) cultivars with contrasting stress tolerance, on its antioxidant capacity, oxidative modification of proteins, status of proteolytic activity and proteomic alterations, when grown in sand cultures. Seedlings exposed to WD and Al-excess for 24–72 h showed growth reduction, increased protein carbonylation in the tissues and increased proteolysis. In WD/Al-sensitive cv. Malviya-36, the combined stresses caused more reduction in growth compared to the individual stresses. Immunoblot analysis of protein carbonyls from root/shoot extracts revealed increased oxidatively modified proteins due to WD and Al-excess. When exposed to either WD, Al-excess or combined stresses, cv. Malviya-36 seedlings showed increased proteolysis, more activity bands corresponding to proteolysis and more oxidized proteins than cv. Vandana (WD /Al-tolerant) seedlings. The antioxidant capacity appeared to be greater in cv. Vandana (tolerant) than cv. Malviya-36 (sensitive) measured by DPPH assay. Proteins from rice shoots, separated by 2DE, when analyzed by PDQuest, revealed nearly 200 clear spots, among which 55 were differentially abundant under individual and combined stresses. MALDI-TOF mass spectrometry of differentially abundant proteins revealed that many chloroplast and photosynthesis-related proteins were downregulated, 6 proteins disappeared and the expression of calmodulin and ABA/stress-induced proteins was specifically induced in the sensitive cultivar under combined stresses indicating that photosynthesis was affected in this cultivar under combined stresses.

Pervasive tree-growth reduction in Tibetan juniper forests

Recent forest declines have been reported at many sites across the world and attributed largely to global-warming induced droughts. Occurrence of forest declines before the global warming is not well understood, especially with regard to its long-term characteristics. Here, we use tree-ring data to detect periods of growth reduction in 1429 juniper trees from 48 sites on the Tibetan Plateau (TP). We find that tree-growth reduction has occurred intermittently and dispersedly over the TP in the past 350 years. The growth reductions among trees could be synchronized at site level in different time, reflecting episodes of decreased forest health. Tree-growth reduction has been alleviated since the 1980s; sites that do show growth reduction events in recent decades are located at higher elevations and are more sensitive to winter mean temperature. We conclude that the pervasive tree-growth reductions may be related to irregular natural disturbances than climatic anomalies. The state of forest health can be estimated by identifying episodes of synchronous tree-growth reduction. Our findings help account for historical growth reduction in the assessment of forest health risks under future climate change.

Action of formulated rosemary against Meloidogyne incognita in soybean

The damage caused by nematodes has been severe in many crops in Brazil, causing a reduction in agricultural yield. The objective of this work was to evaluate the efficiency of a formulation, elaborated with extract of the rosemary (Rosmarinus officinalis) and cassava bark, on the control of nematode Meloidogyne incognita in soybean. The doses evaluated were 0.0; 25; 50; 100; 150 and 200 mL of the dried formulation per pot of 3 L containing soybean plants. The experiment was conducted in a greenhouse, in a randomized block design, with five replications. We evaluated dried and fresh masses of aerial part, fresh mass of root, and the number of egg mass, galls and second stage juveniles (J2) and eggs in root and soil. The soybean plants showed growth reduction resulting from the interaction of the formulation, maybe due a phytotoxic effect from cassava bark. There was allelopathic effect in soybean plants treated with formulated made with cassava bark + aqueous extract of rosemary, evidenced by inhibition in plant development according to the increase in doses of the formulated. Moreover, the formulated was not efficient in the control and or reduction of M. incognita.

The efficacy and side-effects of oil-based adjuvants emulsified Vibrio anguillarum bivalent inactivated vaccine in turbot (Scophthalmus maximus) under production mode

Turbot (Scophthalmus maximus) is an important commercial fish in China, and Vibrio anguillarum is a common pathogen of turbot. Oil emulsified vaccines have been widely used to protect fish against V. anguillarum with long-term immune responses in several fish species. Side-effects, such as adhesions and growth reduction caused by oil-based adjuvants, however, limit the application of oil emulsions in turbot. In this study, turbot V. anguillarum serotype O1 and O2 bivalent inactivated vaccines were emulsified as water-in-oil (W/O) emulsions with four kinds of oil-based adjuvants: Freund's incomplete adjuvant (FIA), MOBIL™ Marcol 52 (Marcol 52), SEPPIC Montanide™ ISA 763 A VG (ISA 763) and ISA 780 (ISA 780). Vaccine protection efficiency, fish adhesions, and growth were tested under production mode. The relative percent of survival (RPS) of W/O vaccines was all higher than that of the water-based (WB) vaccine at 7 days post vaccination. At 30 days post vaccination, the RPS of all vaccinated groups was over 90%, and most of the specific antibody titers of W/O vaccine-vaccinated fish were significantly higher than those of WB vaccines. Fish immunized with FIA, ISA 763, and ISA 780 adjuvants W/O vaccine showed serious tissue adhesions after vaccination, and their weight was significantly lower than control fish at 30 days post vaccination. Only slight or minor adhesions were observed in WB and Marcol 52 adjuvant vaccinated fish, which did not show growth reduction. These results indicate that Marcol 52 is a well-tolerated oil-based adjuvant for turbot, and could be used in vaccine development in further study.

Housefly (Musca domestica) Larvae Preparations after Removing the Hydrophobic Fraction Are Effective Alternatives to Fish Meal in Aquaculture Feed for Red Seabream (Pagrus major)

Insects are an attractive alternative to fish meal (FM) as a sustainable protein source in aquaculture feed that does not negatively impact the marine ecosystem. Despite housefly (Musca domestica) larvae having adequacy of amino acid profiles, they have sometimes been reported to be inferior to FM, especially for marine carnivorous fish species. Here, we report that the removal of the hydrophobic fractions from housefly larvae enables significant replacement of FM in the diet of the red seabream (Pagrus major). In a feeding trial, housefly (HF) larvae that had the hydrophobic fraction removed as a complete substitution for 70% FM produced satisfactory growth. However, HF larvae that were supplemented with the hydrophobic fraction resulted in significant growth reduction. Growth recovery was incomplete by supplementation of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) to undefatted HF larvae, being equivalent to that of fatty acid content with a control diet. Moreover, fish with a dietary intake of catechol identified from the hydrophobic fraction of the HF showed growth reduction and morphological alterations in the intestine. Our findings indicate that the hydrophobic fraction from HF larvae contains a negative factor for fish growth and eliminating the fraction from HF larvae is thought to be an important process for sustainable aquaculture.

Antimicrobial Activity of Probiotics against Endodontic Pathogens:- A Preliminary Study

AbstractIntroduction: The purpose of this study was to evaluate the antibacterial effectiveness of probiotics lactobacilli group and Bifidobacterium against Enterococcus faecalis and Candida albicans in both planktonic stage and biofilm stage. Materials and Methods: Phase 1 of the study was conducted by agar well diffusion method. About 0.5 ml of test pathogen culture was inoculated on 20 ml of molten agar and allowed to solidify. 4–5 circular wells of diameter 8–10 mm were punched in each poured plates and 150 μl of diluted test samples were added to the wells. Phase 2 was deferred antagonism test, wherein purified culture of pathogen strain was streaked at right angle to the original producer growth and incubated at 37°C for 24 h. Zone of inhibition was measured for both the phases. Phase 3 biofilm stage evaluation was conducted by mixing 9 ml of 30% poloxamer 407 and De Man, Rogosa and Sharpe (MRS) broth in a test tube with 500 μl of either pathogen, together with 500 μl of test probiotic strains and incubated (37°C, 48 h), followed by serially diluting the mixture by 1 ml into 9 ml sterile saline till 108 dilutions for evaluation of colony-forming unit/ml counts. Controls were endodontic pathogens in 30% poloxamer with MRS broth and no probiotics. Results: Results were evaluated and statistically analysed using one-way analysis of variance and unpaired t-test. In the planktonic stage, probiotics showed inhibitory activity against endodontic pathogens with valid statistical significance (P < 0.05), while there was no activity by deferred antagonism method. In biofilm stage, all three probiotics showed growth reduction for E. faecalis, while lactobacilli group showed reduction in C. albicans colonies. Conclusion: This preliminary study suggested that probiotics are effective for preventing the growth of endodontic pathogens in vitro. Poloxamer could be utilised as an ideal delivery vehicle for probiotics.

Diagnosis of apple replant disease (ARD): Microscopic evidence of early symptoms in fine roots of different apple rootstock genotypes

Apple replant disease (ARD) is a problem of high economic relevance in tree nurseries and apple orchards worldwide. After replanting, plants show growth reduction, reduced yield, and damaged root systems. The disease’s decade-long persistence in soil exacerbates the situation where alternative cultivation areas and ecologically safe soil decontamination measures are lacking. The etiology is still unclear and there are neither clear causal factors nor reliable parameters (except growth data from plant bioassays) for the early detection of the disease in plants or from samples from potentially affected soils. We report on greenhouse pot trials with the susceptible rootstock Malus domestica ‘M26’ grown in soils of ARD-affected as well as grass plots from three different field sites. Both gamma-irradiated ARD soils and grass soils served as control soils. The aim was to develop a diagnostic tool for the early detection of ARD. In fine roots of first to third order, we assessed the root structure, the root hair density, the cellular damages in the outer layers, and the cell vitality. After only two weeks in ARD soil, ‘M26’ reacted with cell necroses and blackening in a characteristic pattern, impaired root hair development, and low cell vitality. These symptoms were confirmed in Malus domestica ‘Bittenfelder’ and Malus-hybrid B63. Root systems grown in gamma-irradiated soils were almost symptom-free while those from grass soils showed different and only minor alterations. Thus, we suggest selected fine root symptoms to be used for an early diagnosis of ARD, e.g. in plant breeding selections and soil surveys.

Extending effect of a wind disturbance: mortality of Abies sachalinensis following a strong typhoon in a natural mixed forest

ABSTRACTStrong wind constitutes the major force behind disturbance of northern Japanese forests. Canopy gaps induced by disturbance are responsible for subsequent recovery of the stand (i.e. enhancement of growth and recruitment). There is also a possibility that a sudden change in stand structure, involving significant microclimatic alterations, results in further stand degradation. We therefore examined a hypothesis proposing that wind disturbance causes indirect and delayed negative effects on the demography of Abies sachalinensis, a dominant conifer species of northern Japanese natural mixed forests. Data for all trees in a 3-ha study stand with diameter at breast height ≥10 cm were recorded for over 10 years, including the period of severe wind disturbance induced by Typhoon Songda in 2004. We found that the total amount of dead A. sachalinensis in the post-disturbance period was equivalent to that in the wind disturbance. The mortality of the species was generally high in larger trees. Within 1–2 years immediately after the disturbance, dead trees frequently presented the uprooted form despite there being no record of strong winds, suggesting that the physical influence of the disturbance persisted. Moreover, these dead trees showed spatial association with trees in the surrounding trees that died due to strong wind. In contrast, most A. sachalinensis trees that died 3–8 years later showed growth reduction after the disturbance. We conclude that a strong wind disturbance can have long-term influence on the stand dynamics, during which the possible cause of tree deaths changes gradually from physical damage to physiological stress.

Effects of the herbicide glyphosate on non-target plant native species from Chaco forest (Argentina)

Agriculture based on transgenic crops has expanded in Argentina into areas formerly occupied by Chaco forest. Even though glyphosate is the herbicide most widely used in the world, increasing evidence indicates severe ecotoxicological effects on non-target organisms as native plants. The aim of this work is to determine glyphosate effects on 23 native species present in the remaining Chaco forests immersed in agricultural matrices. This is a laboratory/greenhouse approach studying acute effects on seedlings after 21 days. A gradient of glyphosate rates (525, 1050, 2100, 4200, and 8400g ai/Ha; recommended field application rate (RFAR) = 2100g ai/Ha) was applied on four-week seedlings cultivated in a greenhouse and response variables (phytotoxicity, growth reduction, and sensitivity to the herbicide) were measured. This gradient of herbicide rates covers realistic rates of glyphosate applications in the crop field and also those that can reach vegetation of forest relicts by off-target drift and overspray. Testing was performed following guidelines for vegetative vigour (post-germination spray). All species showed lethal or sublethal effects after the application of the 25% of RFAR (50% of species showed severe phytotoxicity or death and 70% of species showed growth reduction). The results showed a gradient of sensitivity to glyphosate by which some of the studied species are very sensitive to glyphosate and seedlings died with 25% of RFAR while other species can be classified as herbicide-tolerant. Thus, the vegetation present in the forest relicts could be strongly affected by glyphosate application on crops. Lethal and sublethal effects of glyphosate on non-target plants could promote both the loss of biodiversity in native forest relicts immersed in the agroecosystems and the selection of new crop weeds considering that some biotypes are continuously exposed to low doses of glyphosate.

Role of fatty acid salts as anti Acanthamoeba agents for disinfecting contact lens.

Acanthamoeba is found in seawater, fresh water, and soil and is an opportunistic pathogen that causes a potentially blinding corneal infection known as Acanthamoeba keratitis. The anti-amoeba activity of 9 fatty acid salts (potassium butyrate (C4K), caproate (C6K), caprylate (C8K), caprate (C10K), laurate (C12K), myristate (C14K), oleate (C18:1K), linoleate (C18:2K), and linolenate (C18:3K)) was tested on Acanthamoeba castellanii ATCC 30010 (trophozoites and cysts). Fatty acid salts (350 mM and pH 10.5) were prepared by mixing fatty acids with the appropriate amount of KOH. C8K, C10K, and C12K showed growth reduction of 4 log-units (99.99% suppression) in A. castellanii upon 180 min incubation at 175 mM, whereas the pH-adjusted control solution showed no effect. After the amoeba suspension was mixed with C10K or C12K, cell membrane destruction was observed. The minimum inhibitory concentration of C10K and C12K was also determined to be 2.7 mM. Confirmation tests were conducted using contact lenses to evaluate the effectiveness of C10K and C12K as multi-purpose solutions. Experiments using increasing concentrations showed reduced numbers of living cells in C10K (5.5 mM, 10.9 mM) and in C12K (5.5 mM, 10.9 mM). These results demonstrate the inhibitory activity of C10K and C12K against A. castellanii and indicate their potential as anti-amoeba agents.

Combining drought QTLs and bacterial blight Xa-genes to control bacterial blight disease under drought stress

Crops under climate change will be simultaneously exposed to multiple stresses of biotic and abiotic nature. To control rice bacterial blight (BB), near-isogenic lines carrying Xa genes were previously developed, while rice near isogenic lines (NILs) with drought yield QTLs (qDTY) were selected for rice yield improvement under drought conditions. In this study, the response of 17 rice lines to simultaneous BB and drought stresses were evaluated in screenhouse trials and field trials to evaluate their response to exposure to BB and drought simultaneously. Under drought stress, qDTY NILs with their shorter growing period were less affected, while IR24 and IRBB4 showed growth reduction and inhibition of flowering under field conditions. NILs with BB resistance (R) Xa gene alone showed resistance to Xanthomonas oryzae pv. oryzae (Xoo) strains carrying the corresponding avirulence gene, except in genotype IRBB4 with the Xa4 R gene that, although resistant, showed a significant increase in disease severity under drought stress after inoculation with Xoo strain PXO61 (avrXa4) compared to irrigated conditions. IR64 introgression lines (IR87705-6-9-B, IR87707-445-B-B-B, IR87707-446-B-B-B) with the combination of the Xa4 R gene and qDTY showed resistance to Xoo strains PXO61 (avrXa4) and PXO145 (avrXa4) under irrigated conditions but were less resistant under drought. Vandana qDTY NILs were susceptible to all Xoo strains under both irrigated and drought stress conditions, but were more resistant under drought. These results highlight the wide genotypic variation among rice lines in response to BB under drought stress and the advantage of trait combinations (Xa+qDTY) to confer drought tolerance and BB resistance under unfavorable future climate conditions.

Involvement of acyl-CoA synthetase genes in n-alkane assimilation and fatty acid utilization in yeast Yarrowia lipolytica.

Here, we investigated the roles of YAL1 (FAA1) and FAT1 encoding acyl-CoA synthetases (ACSs) and three additional orthologs of ACS genes FAT2-FAT4 of the yeast Yarrowia lipolytica in the assimilation or utilization of n-alkanes and fatty acids. ACS deletion mutants were generated to characterize their function. The FAT1 deletion mutant exhibited decreased growth on n-alkanes of 10-18 carbons, whereas the FAA1 mutant showed growth reduction on n-alkane of 16 carbons. However, FAT2-FAT4 deletion mutants did not show any growth defects, suggesting that FAT1 and FAA1 are involved in the activation of fatty acids produced during the metabolism of n-alkanes. In contrast, deletions of FAA1 and FAT1-FAT4 conferred no defect in growth on fatty acids. The wild-type strain grew in the presence of cerulenin, an inhibitor of fatty acid synthesis, by utilizing exogenously added fatty acid or fatty acid derived from n-alkane when oleic acid or n-alkane of 18 carbons was supplemented. However, the FAA1 deletion mutant did not grow, indicating a critical role for FAA1 in the utilization of fatty acids. Fluorescent microscopic observation and biochemical analyses suggested that Fat1p is present in the peroxisome and Faa1p is localized in the cytosol and to membranes.

Listeria monocytogenes Mutants with Altered Growth Phenotypes at Refrigeration Temperature and High Salt Concentrations

Listeria monocytogenes can survive and grow in refrigerated temperatures and high-salt environments. In an effort to better understand the associated mechanisms, a library of ∼ 5,200 transposon mutants of LS411, a food isolate from the Jalisco cheese outbreak, were screened for their ability to grow in brain heart infusion (BHI) broth at 5°C or in the presence of 7% NaCl and two mutants with altered growth profiles were identified. The LS522 mutant has a transposon insertion between secA2 and iap and showed a significant reduction in growth in BHI broth at 5°C and in the presence of 7% NaCl. Reverse transcriptase quantitative PCR (RT-qPCR) revealed a substantial reduction in the expression of iap. Additionally, a hypothetical gene (met), containing a putative S-adenosylmethionine-dependent methyltransferase domain, downstream of iap had downregulated expression. In-frame deletion mutants of iap and met were created in LS411. The LS560 (LS411 Δiap) mutant showed reduced growth at 5°C and in the presence of 7% salt, confirming its role in cold and salt growth attenuation. Surprisingly, the LS655 (LS411 Δmet) mutant showed slightly increased growth during refrigeration, though no alteration was seen in salt growth relative to the wild-type strain. The LS527 mutant, containing an insertion 36 bp upstream of the gbu operon, showed reduced expression of the gbu transcript by RT-qPCR and also showed growth reduction at 5°C and in the presence of 7% salt. This attenuation was severely exacerbated when the mutant was grown under the combined stresses. Analysis of the gbu operon deletion mutant showed decreased growth in 7% salt and refrigeration, supporting the previously characterized role for this gene in cold and salt adaptation. These studies indicate the potential for an intricate relationship between environmental stress regulation and virulence in L. monocytogenes.

In vitro amoebicidal activity of ethanol extracts of Arachis hypogaea L., Curcuma longa L. and Pancratium maritimum L. on Acanthamoeba castellanii cysts

Acanthamoeba castellanii causes amoebic keratitis which is a painful sight-threatening disease of the eyes. Its eradication is difficult because the amoebas encyst making it highly resistant to anti-amoebic drugs, but several medicinal plants have proven to be more effective than the usual therapy. This study aimed to evaluate the in vitro amoebicidal activity of ethanol extracts of Arachis hypogaea L. (peanut), Curcuma longa L. (turmeric), and Pancratium maritimum L. (sea daffodil) on A. castellanii cysts. Acanthamoeba were isolated from keratitic patients, cultivated on 1.5% non-nutrient agar, and then incubated with different concentrations of plant extracts which were further evaluated for their cysticidal activity. The results showed that all extracts had significant inhibitory effect on the multiplication of Acanthamoeba cysts as compared to the drug control (chlorhexidine) and non-treated control, and the inhibition was time and dose dependent. The ethanol extract of A. hypogaea had a remarkable cysticidal effect with minimal inhibitory concentration (MIC) of 100 mg/ml in all incubation periods, while the concentrations of 10 and 1 mg/ml were able to completely inhibit growth after 48 and 72 h, respectively. The concentrations 0.1 and 0.01 mg/ml failed to completely inhibit the cyst growth, but showed growth reduction by 64.4-82.6% in all incubation periods. C. longa had a MIC of 1 g and 100 mg/ml after 48 and 72 h, respectively, while the concentrations 10, 1, and 0.1 mg/ml caused growth reduction by 60-90.3% in all incubation periods. P. maritimum had a MIC of 200 mg/ml after 72 h, while the 20-, 2-, 0.2-, and 0.02-mg/ml concentrations showed growth reduction by 34-94.3% in all incubation periods. All extracts seemed to be more effective than chlorhexidine which caused only growth reduction by 55.3-80.2% in all incubation periods and failed to completely inhibit the cyst growth. In conclusion, ethanol extracts of A. hypogaea, C. longa, and P. maritimum could be considered a new natural agent against the Acanthamoeba cyst.

PHYSIOLOGICAL AND BIOCHEMICAL CHANGES IN CATHARANTHUS ROSEUS L. IN RESPONSE TO BORON NUTRITION

Catharanthus roseus L., a medicinally important plant was grown till maturity at varying levels of boron (0.033, 0.066, 0.33 and 3.3 mg B L−1) supply. Optimum yield was observed in plants receiving 0.33 mg B L−1. Plants receiving deficient boron showed growth reduction and visual symptoms such as chlorosis and cupping of young emerging leaves and apical tip necrosis. The number and size of the flowers, pods and seeds formed and the pollen viability of the boron deficient plants was markedly reduced. The threshold values for deficiency and toxicity were 57 and 79 μg B g−1 dry weight for vegetative growth and 60.4 and 68.9 μg B g−1 dry weight for reproductive growth, respectively, and is reported for the first time in periwinkle. An increase was observed in reducing and non-reducing sugars and in activity of acid phosphatase and ribonuclease in boron stressed plants.

First Report of Tomato torrado virus in Tomato Crops in France

In June 2008, tomato (Solanum lycopersicum L.) plants cv. Fer De Lance (De Ruiter Seeds, Bergschenhoek, the Netherlands) grown in greenhouses near Perpignan (southern France) showed growth reduction and necrotic lesions on fruits, stems, and basal parts of the leaves. Tomato torrado virus (ToTV) was suspected on the basis of symptoms and its recent description in Spain (4). Primer set A (3), designed to ToTV RNA-2, was used for reverse transcription (RT)-PCR experiments on RNA extracted from four infected plants and allowed the amplification of a 493-bp fragment. No amplification was observed from healthy plant extracts. The RT-PCR product was directly sequenced (GQ303330) and a BLAST search in GenBank revealed 99.8- and 99.5%-nt identity with Polish (EU563947) and Spanish type strain (DQ388880) isolates of ToTV, respectively. Double-antibody sandwich-ELISA tests were conducted on these four samples to check for the presence of other viruses commonly found in tomato crops in France. Tomato spotted wilt virus, Parietaria mottle virus, Cucumber mosaic virus, Tomato mosaic virus, and Potato virus Y were not detected but Pepino mosaic virus (PepMV) was detected in all samples. ToTV was mechanically transmitted to Physalis floridana but PepMV was not. This plant was used to inoculate healthy tomatoes that served as a ToTV source for further experiments. Mechanical inoculation to test plants showed that Nicotiana benthamiana, N. clevelandii, N. debneyi, N. glutinosa, Capsicum annuum, Solanum melongena, and some tomato cultivars (including Fer De Lance), in which typical necrotic symptoms were observed, were systemically infected by the virus. Isometric particles ~28 nm in diameter were observed by electron microscopy in crude extracts of infected plants negatively stained with 1% ammonium molybdate, pH 7. To confirm ToTV identification, whitefly transmission experiments were performed with Trialeurodes vaporariorum and Bemisia tabaci. Adult whiteflies were placed in cages with infected tomato plants for 1-, 24-, or 48-h acquisition access periods (AAP) before transferring them by groups of ~50 on susceptible tomato plantlets placed under small containers (six plants per AAP). Forty-eight hours later, plants were treated with an insecticide and transferred to an insect-proof containment growth room. Ten days later, RNA preparation from all plants was tested by RT-PCR for the presence of ToTV. No transmission was observed with a 1-h AAP. With a 24-h AAP, transmission to four of six test plants was observed with both whitefly species, while at 48 h, AAP transmission to three and four plants of six was observed with T. vaporariorum and B. tabaci, respectively. Noninoculated control plants were all negative by RT-PCR. These experiments confirm T. vaporariorum and B. tabaci as natural vectors of ToTV as previously described (1,2). ToTV has been already reported in Spain, Poland, Hungary, and Australia, but to our knowledge, this is the first report of ToTV in France. Our detection of ToTV in April 2009 from the same area revealed 7 positive tomato plants of 17 tested. This observation suggests the persistence of the disease in the Perpignan Region.