Ethanol Fermentation of Starch from Field Peas

Field peas (Pisum sativum) were evaluated as a potential feedstock for ethanol production. Ground peas were dry‐milled and separated into starch, protein, and fibrous fractions by air classification. Starch‐enriched fractions prepared from whole peas and dehulled peas contained 73.7% wt and 77.8% wt starch, respectively, a nearly two‐fold enrichment compared with whole peas. The fractions were liquefied and saccharified using industrial α‐amylase and glucoamylase at recommended enzyme loadings. A final ethanol concentration of 11.0% (w/v) was obtained in 48–52 hr, with yields of 0.43–0.48 g of ethanol/g of glucose. Starch present in whole ground peas was also saccharified and fermented, with 97% of the starch fermented when an autoclaving step was included in the liquefaction stage.     

Genetic diversity assessment of Bulgarian durum wheat (<Emphasis Type="Italic">Triticum durum</Emphasis> Desf.) landraces and modern cultivars using microsatellite markers

The genetic diversity in a Triticum durum Desf. collection, consisting of 102 Bulgarian landraces, nine Bulgarian and 25 introduced cultivars was studied using 14 highly polymorphic microsatellite markers. A total of 100 alleles were identified, with an average of 7.14 alleles per marker. The gene diversity values (He) of the markers for the total samples ranged from 0.23 (WMS357 and WMS631) to 0.77 (WMS46), with an average of 0.52. Within the landraces that were collected from 18 sites in Southern Bulgaria showed 2–11 alleles per locus with an average of 6.07. The microsatellite analysis suggests that the genetic diversity among landraces is lower compared to the diversity levels for durum wheat in countries close to the main centers of wheat domestication. Breeding activities have caused significant reduction of the allelic polymorphism, elimination of rare alleles, and increase in the number of common alleles and the frequency of dominating alleles.     

Multivariate Analysis of the Agricultural Management Presence of Sorghum Halepense (L.) Pers. Relationships in Maize Crops

Sorghum halepense (L.) Pers. is one of the most troublesome weeds in warm climates. Its control is difficult, and understanding the factors affecting its spreading is crucial. A study was conducted in 47 commercial maize fields, which account for more than 400 ha in the Spanish provinces of Albacete, Badajoz and Madrid, to analyse the distribution of S. halepense as a function of various agricultural variables. The results showed significant effects of agricultural management on the presence of this weed. Crop rotation decreased the infestation of S. halepense. Furrow irrigation system favored the establishment of large patches with high plant density, while the sprinkler irrigation system favored the presence of isolated plants or small patches. Apparently, moldboard tillage promoted the establishment of large patches. The combination of different variables also had effects on the characteristics of the present infestations, and its management could lead to a better control in maize fields.     

Gill denervation eliminates the barostatic reflex in a neotropical teleost,the tambaqui (<Emphasis Type="Italic">Colossoma macropomum</Emphasis>)

The baroreflex is one of the most important regulators of cardiovascular homeostasis in vertebrates. It begins with the monitoring of arterial pressure by baroreceptors, which constantly provide the central nervous system with afferent information about the status of this variable. Any change in arterial pressure relative to its normal state triggers autonomic responses, which are characterized by an inversely proportional change in heart rate and systemic vascular resistance and which tend to restore pressure normality. Although the baroreceptors have been located in mammals and other terrestrial vertebrates, their location in fish is still not completely clear and remains quite controversial. Thus, the objective of this study was to locate the baroreceptors in a teleost, the Colossoma macropomum. To do so, the occurrence and efficiency of the baroreflex were both analyzed when this mechanism was induced by pressure imbalancements in intact fish (IN), first-gill-denervated fish (G1), and total-gill-denervated fish (G4). The pressure imbalances were initiated through the administration of the α₁-adrenergic agonist phenylephrine (100 µg kg^?1) and the α₁-adrenergic antagonist prazosin (1 mg kg^?1). The baroreflex responses were then analyzed using an electrocardiogram that allowed for the measurement of the heart rate, the relationship between pre- and post-pharmacological manipulation heart rates, the time required for maximum chronotropic baroreflex response, and total heart rate variability. The results revealed that the barostatic reflex was attenuated in the G1 group and nonexistent in G4 group, findings which indicate that baroreceptors are exclusively located in the gill arches of C. macropomum.     

Effects of rapid global warming at the Paleocene-Eocene boundary on neotropical vegetation

Temperatures in tropical regions are estimated to have increased by 3° to 5°C, compared with Late Paleocene values, during the Paleocene-Eocene Thermal Maximum (PETM, 56.3 million years ago) event. We investigated the tropical forest response to this rapid warming by evaluating the palynological record of three stratigraphic sections in eastern Colombia and western Venezuela. We observed a rapid and distinct increase in plant diversity and origination rates, with a set of new taxa, mostly angiosperms, added to the existing stock of low-diversity Paleocene flora. There is no evidence for enhanced aridity in the northern Neotropics. The tropical rainforest was able to persist under elevated temperatures and high levels of atmospheric carbon dioxide, in contrast to speculations that tropical ecosystems were severely compromised by heat stress.     

The type III effector PthG of <Emphasis Type="Italic">Pantoea agglomerans</Emphasis> pv. <Emphasis Type="Italic">gypsophilae</Emphasis> modifies host plant responses to auxin,cytokinin and light

Pantoea agglomerans pvs. gypsophilae and betae are related gall-forming bacteria. While P. agglomerans pv. beta initiates gall formation on both beet and gypsophila, the gypsophila pathovar causes gall formation only on gypsophila. PthG is a type III effector determining host range of these pathogens, initiating the hypersensitivity response in beet, but is a virulence factor in gypsophila. The role of PthG and its mode of action in pathogenicity remain unclear. Transgenic Nicotiana tabacum plants expressing pthG were created. PthG over-expression was often lethal, and surviving pthG-bearing lines showed morphological and developmental abnormalities such as leaf deformation and abnormal vascular branching, dwarf stature, loss of apical dominance, seedling apical meristem loss, rapid germination, reduced fertility, plants which cease growth for several weeks later producing a new lateral shoot, and loss of endophyte resistance (bearing unusual saprophyte populations). Some transformants required light for seed germination and showed rapid seedling greening. In in vitro assays PthG expression modified responses to auxin and cytokinin, inhibiting root and shoot production but not callus formation. In vitro differentiation responses to light were modified by PthG expression. This effector may interfere in the plant auxin signalling pathways resulting in higher observed auxin and ethylene levels, and subsequent blockage of root and shoot development. Apparently PthG tunes the host response to high hormone levels, changing the developmental response. Since shoot and root development are delayed, we hypothesize that callus/gall formation is supported by this activity. However, interference by PthG with hormone and light signalling does not explain all the responses observed in pthG-bearing lines.     

Spring frost and decay fungi are implicated in suppressing aspen re-growth following partial cleaning in juvenile stands

? Aspen (Populus tremuloides Michx.) regenerates at high densities following manual cleaning.

? Ten-year-old stands located near Lac La Biche and Peace River, Alberta were manually cleaned to three densities (0, 500 or 1 500 stems ha^?1) at three times (bud set, dormancy or bud flush) to test the hypothesis that maintaining residual aspen reduces regeneration.

? At Lac La Biche up to 98% of the aspen regeneration died in the partially-cleaned plots compared to 67% at Peace River five years post-treatment. A spring frost in the second growing season at Lac La Biche is hypothesized to be the inciting factor predisposing the stump sprouts to infection by decay fungi such as Armillaria root rot, resulting in reduced density and height of the aspen regeneration at Lac La Biche relative to Peace River. Drought and ungulate herbivory provided additional stresses. The high mortality of aspen regeneration at Lac La Biche shifted the understory regeneration from aspen to balsam poplar (Populus balsamifera L.).

? These results indicate that maintaining 1 500 stems ha^?1 of residual aspen will not effectively control the re-sprouting of aspen; however, the vulnerability of aspen regeneration to spring frost and other stressors can nearly eradicate the re-growth of aspen.

     

Induction of Resistance to Penicillium digitatum in Grapefruit by β-Aminobutyric Acid

-Aminobutyric acid (BABA), an inducer of pathogen resistance in plants, induced disease resistance in reproductive parts of the plant, such as grapefruit peel tissue. Application of BABA to specific wound sites on the fruit peel surface induced resistance to Penicillium digitatum, the main postharvest pathogen of citrus fruit, in a concentration-dependent manner, being most effective at 20mM, and rather less effective at either higher or lower concentrations. The effect of BABA in inducing resistance to P. digitatum in the fruit peel surface was local and limited to the vicinity (within 1–2cm) of the BABA-treated site. In addition to inducing pathogen resistance, increasing concentrations of BABA (from 1 to 100mM) also exhibited direct antifungal activity and inhibited P. digitatum spore germination and germ tube elongation in vitro. The induction of resistance to P. digitatum by BABA was accompanied by the activation of various pathogen defense responses in grapefruit peel tissue, including activation of chitinase gene expression and protein accumulation after 48h, and an increase in phenylalanine ammonia lyase (PAL) activity after 72h.