Bioherbicidal potential of a strain of Xanthomonas spp. for control of common cocklebur (Xanthium strumarium)

Several isolates of a previously unreported bacterial pathogen were discovered on common cocklebur seedlings in Chicot County, AR and Washington County, MS. Diseased plants in nature exhibited angular-shaped leaf spotting symptoms on leaf margins and central leaf areas. The isolates were cultured from diseased leaf tissue and tentatively identified as Xanthomonas spp., and their virulence on common cocklebur seedlings compared. The most virulent isolate (LVA987) was used in studies to define disease progression on cocklebur seedlings and to carry out a host range evaluation on various weeds and crop plants. High virulence was found on common cocklebur > marestail (Conyza canadensis) > giant ragweed (Ambrosia trifida) ≥ and common ragweed (Ambrosia artemisifolia). These results suggest this pathogen may be useful for the biological control of these important species of weeds. This is also highly relevant since all of these weeds have evolved resistance to one or more synthetic herbicides and are thus becoming more difficult to control with conventional herbicides.     

High-Level Expression of Fusion Protein Containing 10 Tandem Repeated GLP-1 Analogs in Yeast Pichia pastoris and Its Biological Activity in a Diabetic Rat Model

Glucagon-like peptide-1 (GLP-1), an incretin secreted by intestinal L-cells, can effectively lower blood glucose levels in patients with diabetes. A fusion gene, consisting of 10 tandem repeated GLP-1 analog genes, was expressed at a high level in the yeast Pichia pastoris. SDS polyacrylamide gel electrophoresis (SDS–PAGE), and Western Blotting results showed that fusion protein migrated as a single protein band with a molecular weight of 36 kDa. A biological activity test showed that the GLP-1 analog could significantly lower the level of serum glucose when GLP-1 purified analog was injected into diabetic rats. A potential strategy for large-scale production of fusion protein containing the 10 GLP-1 analogs as discovered, and a single GLP-1 analog was obtained from fusion protein digested with trypsin. This should be inspired foreign expression of medicinal short peptides and be valuable in further research on GLP-1 analog drugs in the treatment of diabetes mellitus.     

Activity rhythms of enzymes in human red blood cell suspensions

Abstract

We have established the presence of a rhythm in the activity of 4 enzymes in in‐vitro cell suspensions of human red blood cells. Glucose 6‐phosphate dehydrogenase and glutamate oxaloacetate transaminase demonstrated semicircadian patterns of activity, while acid phosphatese and acetylcholine esterase exhibited circadian activity rhythms. The ratios between the highest to lowest activities varied from 2:1 to 10:1 among the various enzymes. The affinity of glucose 6 phosphate dehydrogenase to its substrate and coenzyme remained constant throughout the cycle. No evidence was obtained for the presence of a soluble inhibitor at the lower levels of the activity. Sonication of hemolysates with low glucose 6 phosphate dehydrogense activity yielded additional activity comparable to that of the peak activity. Sonication of hemolysates from the time of the peak activity did not change the original activity. The observations point to a role of the cell membrane in the biological clock.     

Fusarium Species Associated with Mango Malformation in Peninsular Malaysia

Mango malformation has become the most important global disease on mango. Fusarium species previously associated with this disease include F. mangiferae, F. mexicanum, F. sterilihyphosum, F. proliferatum, F. subglutinans and F. tupiense. A few strains of F. proliferatum have been reported from Malaysia, but in this study, we report the results of more extensive sampling. The recovered strains were evaluated with morphology, mating tester strain cross‐fertility, amplified fragment length polymorphisms (AFLPs), and partial DNA sequences of the genes encoding translation elongation factor 1‐α (tef‐1α) and β‐tubulin (tub‐2). Amongst the 43 strains evaluated, three species were identified – F. proliferatum, F. mangiferae and F. subglutinans – with F. proliferatum being the most frequent (69%). None of the Fusarium species that appear to originate in the Americas were recovered in Malaysia, which suggests special measures may be warranted to keep these species from entering the country.     

Pseudomonas fluorescens,a potential bacterial antagonist to control plant diseases

Abstract

Fluorescent Pseudomonads belong to plant Growth Promoting Rhizobacteria (PGPR), the important group of bacteria that play a major role in the plant growth promotion, induced systemic resistance, biological control of pathogens etc. Many strains of Pseudomonas fluorescens are known to enhance plant growth promotion and reduce severity of various diseases. The efficacy of bacterial antagonists in controlling fungal diseases was often better as alone, and sometimes in combination with fungicides. The present review refers to occurrence, distribution, mechanism, growth requirements of P. fluorescens and diseases controlled by the bacterial antagonist in different agricultural and horticultural crops were discussed. The literature in this review helps in future research programmes that aim to promote P. fluorescens as a potential bio-pesticide for augmentative biological control of many diseases of agriculture and horticultural importance.     

Female‐borne cues affecting Psyttalia concolor (Hymenoptera: Braconidae) male behavior during courtship and mating

Knowledge of the mechanisms that regulate courtship and mating behavior in Psyttalia concolor (Szépligeti)–a koinobiont endophagous solitary parasitoid of the olive fruit fly, Bactrocera oleae (Rossi), and of other fruit flies–is essential to its mass rearing and management. Augmentative releases of P. concolor for olive fruit fly control started in the Mediterranean areas in the 1950s and still continue with limited success. We determined the influence of visual and chemical cues on courtship and mating behavior of this braconid and the possible effect of the mating status of males and females in the perception of these cues. Our results suggest that integration of visual and chemical stimuli are fundamental for mate location and courtship. Indeed, the optimal response of the male was achieved when physical and chemical cues were simultaneously presented and vision and olfaction worked synergistically.     

Effects of sodium butyrate supplementation on reproductive performance and colostrum composition in gilts

Nutrients are essential for the health and survival of human beings and animals. Also, they play a major role in enhancing reproductive efficiency. The aim of the current study was to investigate the effects of sodium butyrate (SB) on reproductive performance and colostrum composition in gilts. A total of 40 Large White×Landrace replacement gilts (at the age of 160 to 175 days) were fed either a standard diet (control group, n=20) or standard diet top dressed with encapsulated SB at the level of 500 mg/kg (SB group, n=20) from 1 month before mating to 7 days after farrowing. The rate of gilts regular return to estrus after insemination was lower in SB group than the control group. The total number of piglets born (P=0.179) and the litter weight at birth (P=0.063) did not differ between the two treatment groups. However, the mean BW at day 7 tended to be greater in SB group (P=0.051) and average daily gain of piglets was greater (P=0.011) compared with control group. Colostrum samples were collected at parturition and the concentrations of total protein (P=0.197), cholesterol (P=0.161) and lactose (P=0.923) were not influenced by SB supplementation. However, compared with control gilts, colostrum from SB-treated gilts contained lower triglyceride (P=0.050). Moreover, colostrum concentrations of prolactin (P=0.005) and leptin (P=0.006) were significantly lower in SB group. No significant differences were noted for the colostral concentrations of cortisol (P=0.899), thyroxine (P=0.891) or triiodothyronine (P=0.194). The concentration of lipopolysaccharide in colostrum was not influenced by SB supplementation (P=0.972). However, colostrum from SB-treated gilts had significantly lower tumor necrosis factor α (TNFα) (P=0.030) and higher immunoglobulin A (IgA) (P=0.042). Collectively, SB supplementation could reduce the rate of gilts return to estrus, alter the composition of colostrum and enhance the growth rate of piglets. Moreover, SB could alter the immune function of newborn piglets through decreased production of TNFα and increased IgA concentration in colostrum.     

Organic farming affects the potential of a granivorous carabid beetle to control arable weeds at local and landscape scales

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Circadian variations in self-monitoring,a component of executive functions

The objective of this study was to identify circadian rhythms in self-monitoring, a component of executive functions. Participants were 10 undergraduate students, age: 18.5 ± 2.68 years, two male and eight female. They were recorded on a 30-h constant routine protocol; rectal temperature was recorded every minute and performance on a tracking task was assessed every 100 min. Self-monitoring indicators were adjustments of responses to random changes of speed and trajectory of a circle moving on the computer screen. Participants showed better accuracy during the afternoon, with decreases in the morning (06:20 and 08:00 h). These variations showed a phase delay of 2:29 ± 2:19 h with respect to the circadian rhythm of body temperature. In conclusion, there are circadian variations in self-monitoring. The decline in this component of executive functions could cause serious accidents among people working or studying during a morning shift, as well as commuting to and from work or school.