Relationships of Spectral Reflectance with Plant Tissue Mineral Elements of Common Bean (Phaseolus Vulgaris L.) Under Drought and Salinity Stresses

ABSTRACT

Salinity and drought stresses are critical for Phaseolus vulgaris L. growth and development. They affect plants in various ways, including tissue mineral element content. Micro- and macro-elements in leaves of Phaseolus vulgaris L. (cv. ‘Blue lake’ and cv. ‘Terli’) subjected to deficit irrigation and salinity treatments were investigated, both analytically and with regards to their effect on the leaves’ spectral reflectance. B (boron), K (potassium), Mn (manganese), Na (sodium), Si (silicon) and Zn (zinc) appeared to be influenced by stress factors, mainly responding to salinity increase. The leaf spectral reflectance of the plants appeared to be significantly correlated with most of the elements under investigation. Multivariate regression identified a relationship of the reflectance at particular regions of the spectrum with phosphorus and NDVI (normalized difference vegetation index) and indicated a significant correlation with B, Fe (iron), K, Mn, P (phosphorus) and Zn. Moreover, customized spectral indices, exhibiting significantly high correlation with B, Fe, K, Mg (magnesium), Mn, Na, P, Zn and N (nitrogen), were developed.     

Protective and defensive roles of non-glandular trichomes against multiple stresses:structure-function coordination

As superficial structures,non-glandular trichomes,protect plant organs against multiple biotic and abiotic stresses.The protective and defensive roles of these epidermal appendages are crucial to developing organs and can be attributed to the excellent combination of suitable structural traits and chemical reinforcement in the form of phenolic compounds,primarily fl avonoids.Both the formation of trichomes and the accumulation of phenolics are interrelated at the molecular level.During the early stages of development,non-glandular trichomes show strong morphological similarities to glandular ones such as the balloon-like apical cells with numerous phenolics.At later developmental stages,and during secondary wall thickening,phenolics are transferred to the cell walls of the trichomes.Due to the diff use deposition of phenolics in the cell walls,trichomes provide protection against UV-B radiation by behaving as optical fi lters,screening out wavelengths that could damage sensitive tissues.Protection from strong visible radiation is also aff orded by increased surface light refl ectance.Moreover,the mixtures of trichome phenolics represent a superfi-cial chemical barrier that provides protection against biotic stress factors such as herbivores and pathogens.Although the cells of some trichomes die at maturity,they can modulate their quantitative and qualitative characteristics during development,depending on the prevailing conditions of the external biotic or abiotic environment.In fact,the structure and chemical constituents of trichomes may change due to the particular light regime,herbivore damage,wounding,water stress,salinity and the presence of heavy metals.Hence,trichomes represent dynamic protective structures that may greatly aff ect the outcome of many plant–environment interactions.     

Developmental competence of heat stressed oocytes from Holstein and Limousine cows matured in vitro

The negative effects of heat stress on dairy cattle's fertility have been extensively studied, but the relevant knowledge for beef cattle is rather limited. The aims of this study were to investigate the effects of HS during in vitro maturation on the developmental potential of oocytes derived from Limousine and Holstein cows and to estimate the effect of the differential gene expression of important genes in oocytes, cumulus cells and blastocysts in the growth competence between the breeds. In seven replicates, cumulus oocyte complexes from Holstein and Limousine cows were matured for 24 hr at 39°C (controls C; Hol_39, Lim_39) or at 41°C from hour 2 to hour 8 of IVM (treated T; Hol_41, Lim_41), fertilized, and presumptive zygotes were cultured for 9 days at 39°C. Cleavage and embryo formation rates were evaluated 48 hr post-insemination and on days 7, 8 and 9, respectively. From all groups, subsets of cumulus cells, oocytes and blastocysts were analysed for the relative expression of genes related to metabolism, stress, apoptosis and placentation. No difference was detected in cleavage rate or in blastocyst formation rate among the control groups. In both breeds, heat stress reduced blastocyst yield, but at all days the suppression was higher in Limousines. In Holsteins, altered gene expression was detected in cumulus cells (G6PD, GLUT1) and blastocysts (PLAC8), while in Limousines, differences were found in oocytes (G6PD, HSP90AA1), in cumulus cells (CPT1B, HSP90AA1, SOD2) and blastocysts (DNMT, HSP90AA1, SOD2). It appears that Holstein COCs are more tolerant than Limousine COCs, possibly due to compulsory, production driven selection.     

Ultrasonographic findings of the corpus luteum and the gravid uterus during heat stress in dairy cattle

The objectives of this study were to assess alterations in, echogenic appearance, size and blood flow in the corpus luteum, the placentomes and the blood flow in umbilical and uterine arteries that heat stress can cause in cooled pregnant dairy cows. Pregnant cows were allocated in two groups and the gravid uteri, along with the ipsilateral corpora lutea were examined during the winter (group W, n = 9) or the summer (group S, n = 10). The grey-scale ultrasound and colour flow imaging of the corpus luteum and placentome were performed. In addition, the umbilical and uterine artery diameters and haemodynamic parameters in the vessels were calculated. At the time of ultrasonographic examination, cortisol concentrations were higher, and progesterone levels tended to be lower in group S compared to group W. The grey-scale ultrasound evaluation of corpora lutea and placentomes was lower in group S compared to group W. The diameter of umbilical artery and the blood volume in the vessel were less in group S than in group W. We infer that heat stress affects foetal blood supply and possibly the structure of placentomes and corpora lutea, but it differently affects the blood flow characteristics in the umbilical and uterine arteries.     

Determination of anabolic steroids in muscle tissue by liquid chromatography-tandem mass spectrometry

A specific and sensitive method based on liquid chromatography-tandem mass spectrometry using atmospheric pressure chemical ionization (LC-APCI-MS/MS) has been developed for the determination of four anabolic steroids [trenbolone, methylboldenone, methyltestosterone, and norethandrolone] in bovine muscle. Methyltestosterone- d 3 was used as internal standard. The procedure involved enzymatic hydrolysis, extraction with tert-butyl methyl ether, defattening, and final cleanup with solid-phase extraction with Oasis HLB cartridges. The analytes were analyzed by reversed-phase LC-MS/MS, acquiring two diagnostic product ions from the chosen precursor [M + H] (+) for the unambiguous confirmation of hormones. The method was validated according to the European Commission Decision 2002/657/EC for the detection and confirmation of residues in products of animal origin. The limits of detection (LOD) and limits of quantitation (LOQ) were found to be 0.3 ng/g and 1.0 ng/g, respectively. The accuracy and precision have been determined, with recoveries ranging from 83% to 104% and the CV factor not exceeding the value of 7%. The decision limits CCalpha were calculated and ranged from 0.05 to 0.15 ng/g while the detection capabilities CCbeta ranged from 0.09 to 0.25 ng/g. The method proved to be sensitive and reliable and thus renders an appropriate means for residue analysis studies.     

Anti-Inflammatory Potential of Monogalactosyl Diacylglycerols and a Monoacylglycerol from the Edible Brown Seaweed Fucus spiralis Linnaeus

A monoacylglycerol (1) and a 1:1 mixture of two monogalactosyl diacylglycerols (MGDGs) (2 and 3) were isolated from the brown seaweed Fucus spiralis Linnaeus. The structures were elucidated by spectroscopic means (NMR and MS) and by comparison with the literature. Compound 1 was composed of a glycerol moiety linked to oleic acid (C18:1 Ω9). Compounds 2 and 3 contained a glycerol moiety linked to a galactose unit and eicosapentaenoic acid (C20:5 Ω3) combined with octadecatetraenoic acid (C18:4 Ω3) or linolenic acid (C18:3 Ω3), respectively. The isolated compounds were tested for their cytotoxic and anti-inflammatory activity in RAW 264.7 macrophage cells. All of them inhibited NO production at non-cytotoxic concentrations. The fraction consisting of compounds 2 and 3, in a ratio of 1:1, was slightly more effective than compound 1 (IC₅₀ of 60.06 and 65.70 µg/mL, respectively). To our knowledge, this is the first report of these compounds from F. spiralis and on their anti-inflammatory capacity.     

Interactions between residue placement and earthworm ecological strategy affect aggregate turnover and N2O dynamics in agricultural soil

Previous laboratory studies using epigeic and anecic earthworms have shown that earthworm activity can considerably increase nitrous oxide (N₂O) emissions from crop residues in soils. However, the universality of this effect across earthworm functional groups and its underlying mechanisms remain unclear. The aims of this study were (i) to determine whether earthworms with an endogeic strategy also affect N₂O emissions; (ii) to quantify possible interactions with epigeic earthworms; and (iii) to link these effects to earthworm-induced differences in selected soil properties. We initiated a 90-day ¹⁵N-tracer mesocosm study with the endogeic earthworm species Aporrectodea caliginosa (Savigny) and the epigeic species Lumbricus rubellus (Hoffmeister). ¹⁵N-labeled radish (Raphanus sativus cv. Adagio L.) residue was placed on top or incorporated into the loamy (Fluvaquent) soil. When residue was incorporated, only A. caliginosa significantly (p < 0.01) increased cumulative N₂O emissions from 1350 to 2223 μg N₂O-N kg⁻¹ soil, with a corresponding increase in the turnover rate of macroaggregates. When residue was applied on top, L. rubellus significantly (p < 0.001) increased emissions from 524 to 929 μg N₂O-N kg⁻¹, and a significant (p < 0.05) interaction between the two earthworm species increased emissions to 1397 μg N₂O-N kg⁻¹. These effects coincided with an 84% increase in incorporation of residue ¹⁵N into the microaggregate fraction by A. caliginosa (p = 0.003) and an 85% increase in incorporation into the macroaggregate fraction by L. rubellus (p = 0.018). Cumulative CO₂ fluxes were only significantly increased by earthworm activity (from 473.9 to 593.6 mg CO₂-C kg⁻¹ soil; p = 0.037) in the presence of L. rubellus when residue was applied on top. We conclude that earthworm-induced N₂O emissions reflect earthworm feeding strategies: epigeic earthworms can increase N₂O emissions when residue is applied on top; endogeic earthworms when residue is incorporated into the soil by humans (tillage) or by other earthworm species. The effects of residue placement and earthworm addition are accompanied by changes in aggregate and SOM turnover, possibly controlling carbon, nitrogen and oxygen availability and therefore denitrification. Our results contribute to understanding the important but intricate relations between (functional) soil biodiversity and the soil greenhouse gas balance. Further research should focus on elucidating the links between the observed changes in soil aggregation and controls on denitrification, including the microbial community.     

Serological survey of Q fever in Crete, southern Greece

Coxiella burnetii, the causative agent of Q fever, is an obligatory intracellular bacterium with worldwide distribution. The aim of this study was to determine the prevalence of C. burnetii phase II antibodies in two different groups (high and low risk) of healthy human population and investigate the epidemiological characteristics of the infection in the island of Crete (southern Greece). Collection and testing by IFA of 493 sample sera for IgG and IgM antibodies against C. bumetii phase II antigen indicated a prevalence of IgG antibodies of 48.7%. Of the seropositive individuals, 34% also revealed IgM seropositive antibody titers. Analysis of 225 sample sera by IFA from high risk population presented a prevalence for C. burnetii of 62.2%. Our findings revealed that C. burnetii is highly endemic in Crete, indicating a high exposure of the population to the pathogen regardless of occupation or place of residence.     

Molecular typing of Brucella melitensis endemic strains and differentiation from the vaccine strain Rev-1

In the present study forty-four Greek endemic strains of Br. melitensis and three reference strains were genotyped by Multi locus Variable Number Tandem Repeat (ML-VNTR) analysis based on an eight-base pair tandem repeat sequence that was revealed in eight loci of Br. melitensis genome. The forty-four strains were discriminated from the vaccine strain Rev-1 by Restriction Fragment Length Polymorphism (RFLP) and Denaturant Gradient Gel Electrophoresis (DGGE). The ML-VNTR analysis revealed that endemic, reference and vaccine strains are genetically closely related, while most of the loci tested (1, 2, 4, 5 and 7) are highly polymorphic with Hunter-Gaston Genetic Diversity Index (HGDI) values in the range of 0.939 to 0.775. Analysis of ML-VNTRs loci stability through in vitro passages proved that loci 1 and 5 are non stable. Therefore, vaccine strain can be discriminated from endemic strains by allele’s clusters of loci 2, 4, 6 and 7. RFLP and DGGE were also employed to analyse omp2 gene and reveled different patterns among Rev-1 and endemic strains. In RFLP, Rev-1 revealed three fragments (282, 238 and 44 bp), while endemic strains two fragments (238 and 44 bp). As for DGGE, the electrophoretic mobility of Rev-1 is different from the endemic strains due to heterologous binding of DNA chains of omp2a and omp2b gene. Overall, our data show clearly that it is feasible to genotype endemic strains of Br. melitensis and differentiate them from vaccine strain Rev-1 with ML-VNTR, RFLP and DGGE techniques. These tools can be used for conventional investigations in brucellosis outbreaks.