Testicular and Color Variation in the Kissing Bug, Rhodnius brethesi, in Amazonas, Brazil

Abstract Because of the morphological and morphometric variation of testicular follicles in different genera of the subfamily Triatominae, it was of interest to associate those parameters with the different medial pronotal band patterns (wide and narrow) found in Rhodnius brethesi (Matta) (Hemiptera: Reduviidae). This is a wild species often associated with Leopoldina piassaba Wallace (Arecales: Arecaceae) palm, with a geographical distribution restricted to the Amazon region. The specimens used were from the state of Amazonas, and were kept under conditions of 29 ± 1 (°)C, 80 ± 5% RH, 12:12 L:D photoperiod, and were fed weekly on blood from Swiss mice. Three-day-old fasting males were separated in accordance with the patterns of the medial pronotal band, dissected, and the testicles removed. After removal of the testicular membrane, the follicles were spread, drawn by camera lucida, and measured. The results showed that the testis of R. brethesi consists of seven follicles, divided into two groups by length; two long and five short. In specimens with a wide medial pronotal band, the long follicles were 5.4 mm in length, but in specimens with a narrow medial band, the long follicles were 5.64 mm in length. The difference was significant. The short follicles were not different in length, suggesting the presence of a possible complex "brethesi" in the Amazon region.     

Structural characterization and anti-HSV-1 and HSV-2 activity of glycolipids from the marine algae Osmundaria obtusiloba isolated from Southeastern Brazilian coast

Glycolipids were extracted from the red alga Osmundaria obtusiloba from Southeastern Brazilian coast. The acetone insoluble material was extracted with chloroform/methanol and the lipids, enriched in glycolipids, were fractionated on a silica gel column eluted with chloroform, acetone and then methanol. Three major orcinol-positive bands were found in the acetone and methanol fractions, being detected by thin layer chromatography. The structures of the corresponding glycolipids were elucidated by ESI-MS and (1)H/(13)C NMR analysis, on the basis of their tandem-MS behavior and HSQC, TOCSY fingerprints. For the first time, the structure of sulfoquinovosyldiacylglycerol from the red alga Osmundaria obtusiloba was characterized. This molecule exhibited potent antiviral activity against HSV-1 and HSV-2 with EC(50) values of 42 μg/mL to HSV-1 and 12 μg/mL to HSV-2, respectively. Two other glycolipids, mono- and digalactosyldiacylglycerol, were also found in the alga, being characterized by ESI-MS/MS. The structural elucidation of algae glycolipids is a first step for a better understanding of the relation between these structures and their biological activities.     

Lodgepole pine growth as a function of competition and canopy light environment within aspen dominated mixedwoods of central interior British Columbia

Three lodgepole pine and aspen mixedwood sites located in the central interior of British Columbia within the Sub Boreal Spruce (SBS) biogeoclimatic zone were chosen to study the neighbourhood aspen competition and canopy light environment of 14–19-year-old lodgepole pine. All three sites had previously been established as separate research trials designed to explore various silviculture options for controlling aspen competition (aspen brushing, herbicide, thinning and untreated areas). For each site, 33–36 pine trees were selected to represent the observed range of light regimes under the influence of various aspen competition levels. At each sample pine, competition and stand measurements were made and a series of vertical canopy light measurements from the top to the base of the live crown. After an evaluation of a variety of competition indices, the index DRD; sum of the ratio of each of the three nearest neighbour's DBH to the subject pine divided by their distance and, amount of available light at the top of the crown (DIFN_t) were found as the best overall predictors of pine stem volume growth. A site specific exponential relationship of relative pine stem volume growth to DRD was found and minimum growth response competition thresholds were determined, which could provide useful targets where maximizing pine volume is intended. Evaluation of both linear and non-linear models of DIFN_t versus height growth indicated the response to be linear across the observed range of available light. Implications for management are discussed.     

Alleviating soil sickness caused by aerobic monocropping: Responses of aerobic rice to nutrient supply

Yield decline is a major constraint in the adoption of monocropping of aerobic rice. The causes of the yield decline in the continuous aerobic rice system are still unknown. The objective of this study was to determine if nutrient application can mitigate the yield decline caused by continuous cropping of aerobic rice. Micro-plot experiment was conducted in 2005 dry season (DS) in a field where aerobic rice has been grown continuously for eight seasons from 2001 DS at the International Rice Research Institute (IRRI) farm. Pot experiments were done with the soil from the same field where the micro-plot experiment was conducted and aerobic rice has been grown continuously for 10 seasons. Apo, an upland rice variety, was grown under aerobic conditions with different nutrient inputs in field and pot experiments. The field micro-plot experiment showed that micronutrients had insignificant effect on plant growth under continuous aerobic rice cultivation but the combination of N, P, and K mitigated the yield decline of continuous aerobic rice. A series of pot experiments studying the individual effects of nutrients indicated that N application improved plant growth under continuous aerobic rice cropping, while P, K, and micronutrients had no effect. Increasing the rate of N application from 0.23 to 0.90 g per pot in the continuous aerobic rice soil increased the vegetative growth parameters, chlorophyll meter readings, and aboveground N uptake consistently. Our results suggested that N deficiency due to poor soil N availability or reduced plant N uptake might cause the yield decline of continuous cropping of aerobic rice.     

The use of statistical methods to evaluate winter oilseed rape doubled haploids for industrial purposes

Doubled haploid (DH) production is valuable technology in modern plant breeding of oilseed rape. Doubled haploids can be produced from in vitro isolated and cultured microspores, which, instead of forming pollen, develop into haploid embryos. Either spontaneously or after artificial doubling of chromosomes, the arising resulting plants are diploid and fertile, and 100% homozygous for all genes. Biotechnological DH production offers various advantages for plant breeders, including the possibility to obtain homozygous lines rapidly, as well as easy selection due to the absence of heterozygosity. A DH line with desirable agronomic characters can be chosen and introduced into a breeding program as a result of selection for a combination of optimum characters. The study presents the application of uni- and multi-variate statistical methods to evaluate winter oilseed rape DH lines studied in a series of six experiments repeated at different localities and over a number of years. These methods made it possible to estimate individual DH lines under various environmental conditions, including the assessment of the content and stability of two different fatty acid compositions. The aim of the study was to classify and select the best oilseed rape genotypes with regard to the requirements of chemical and biodiesel industry concerning fatty acid compositions at simultaneously high seed yield. The paper contains the results of statistical analysis of 37 genotypes (32 DH lines, 2 parental forms, F₂ and F₃ hybrids and standard cultivar) performed on the basis of experiments carried out at 6 environments. A total of 14 genotypes were found satisfactory (11 stable and 3 unstable) for the chemical industry and 10 genotypes satisfactory (6 stable and 4 unstable) for the biodiesel industry. Among them 5 genotypes had very profitable significant and positive estimates of the main effect for seed yield.     

Greenhouse evaluation of EDTA effectiveness at enhancing Cd,Cr, and Ni uptake in <Emphasis Type="Italic">Helianthus annuus</Emphasis> and <Emphasis Type="Italic">Thlaspi caerulescens</Emphasis>

Background, Aims and Scope  Phytoremediation is a promising means for the treatment of heavy metal contamination. Although several species have been identified as hyperaccumulators, most studies have been conducted with only one metal. Experiments were conducted to investigate the ability of Helianthus annuus and Thlaspi caerulescens to simultaneously uptake Cd, Cr and Ni. Materials and Methods  The efficiency of plants grown in a sandy-loam soil was investigated. The ability of two EDTA concentrations (0.1 and 0.3 g kg⁻¹) for enhancing the phytoremediation of Cd, Cr and Ni at two different metal concentrations (24.75 mg kg⁻¹ and 90 mg kg⁻¹) was studied. Results   Thlaspi hyperaccumulated Ni with 0.1 g kg⁻¹ EDTA. When the EDTA dosage was increased to 0.3 g kg⁻¹, Thlaspi was able to hyperaccumulate both Ni and Cr. Since Thlaspi is a low-biomass plant, it was considered insufficient for full-scale applications. Helianthus annuus hyperacummulated Cr (with 0.1 g kg⁻¹ EDTA) and Cd (0.3 g kg⁻¹ EDTA). Discussion  When the contamination was 8.25 mg kg⁻¹ per metal, the total metal uptake was 10–25% (1.35 to 2.12 mg) higher and had the same uptake selectivity (Cr>>Cd>Ni) for both EDTA levels. It was hypothesized that complexation with EDTA interfered with Ni translocation. For these experiments, the optimal results were obtained with the H. annuus-0.1 g kg⁻¹ EDTA combination. Conclusions  Although the use of EDTA did increase the amount of metal that could be extracted, care should be taken during in-situ field applications. Chelators can also increase the amount of metals that are leached past the root zone. Metal leaching and subsequent migration could lead to ground water contamination as well as lead to new soil contamination. Recommendations and Perspectives  Additional research to identify the optimal EDTA dosage for field applications is warranted. This is necessary to ensure that the metals do not leach past the root zone. Identification of a plant that can hyperaccumulate multiple metals is critical for phytoremediation to be a viable remediation alternative. In addition to being able to hyperaccumulate multiple metals, the optimal plant must be fast growing with sufficient biomass to sequester the heavy metals.     

Influence of time of day on measurement with chlorophyll meters and canopy reflectance sensors of different crop N status

Precision Agriculture - Optical sensors are a promising approach for assessing nitrogen (N) status of vegetable crops. However, their potential may be undermined if time of day influences...     

The cellular structure of cork from Quercus cerris var. cerris bark in a materials’ perspective

Cork in the outer bark of trees is among the valuable raw materials of biological origin due to properties that result mainly from its cellular structure. Large scale commercial utilization of cork has been only achieved with cork from Quercus suber. Another oak species, Quercus cerris, also contains substantial, albeit not continuous, regions of cork that are clearly visible to the naked eye but are so far considered as a waste material.Bark samples of Q. cerris var. cerris trees were collected from the And?r?n province, Turkey. Cork portions were separated and their cellular structure was investigated with optical and electron scanning microscopy observations. The results were compared with Q. suber cork.Q. cerris cork has the typical features of cork tissues with a regular and radially aligned structure of suberized cells without intercellular voids, showing a ring structure and a distinction of earlycork and latecork cells. Solid volume fraction was estimated at 25% (22% in earlycork, 36% in latecork).In Q. cerris cork cells are smaller, cell wall thickness and solid volume fraction are higher, and the tissue is less homogeneous with a higher content of lignified inclusions than in Q. suber cork. These factors will negatively influence quality in regard to density and mechanical properties associated to elasticity. However, this does not impair its use for production of granulates and agglomerates, e.g. for insulation and energy absorption. Separation of the cork fraction from the bark is a step required before further processing and use.     

Halogenated compounds from marine algae

Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds.