Ectomycorrhizal Colonization, Biomass, and Production in a Regenerating Scrub Oak Forest in Response to Elevated CO2

The effects of CO₂ elevation on the dynamics of fine root (FR) mass and ectomycorrhizal (EM) mass and colonization were studied in situ in a Florida scrub oak system over four years of postfire regeneration. Soil cores were taken at five dates and sorted to assess the standing crop of ectomycorrhizal and fine roots. We used ingrowth bags to estimate the effects of elevated CO₂ on production of EM roots and fine roots. Elevated CO₂ tended to increase EM colonization frequency but did not affect EM mass nor FR mass in soil cores (standing mass). However, elevated CO₂ strongly increased EM mass and FR mass in ingrowth bags (production), but it did not affect the EM colonization frequency therein. An increase in belowground production with unchanged biomass indicates that elevated CO₂ may stimulate root turnover. The CO₂-stimulated increase of belowground production was initially larger than that of aboveground production. The oaks may allocate a larger portion of resources to root/mycorrhizal production in this system in elevated rather than ambient CO₂.     

甾体1，4-脱氢和11α-羟基化反应的两种不同微生物转化

Two kinds of micro-organism, Arthrobacter sp. AX86(1,4-dehdrogenator)and Absidia sp. A28(11α-hydroxylator) were used in this experiment. Two different fermentation techniques were performed to accomplish the multiple conversional reactions for producing 16β-methyl-11α, 17α, 21-trihydroxy-1,4-pregnadiene-3,20-dione (Ⅲ) from 16β-methyl-3β, 17α,21-trihydroxy-5α-pregnane-20-one-21-acetate(1) 1)To produce product(Ⅲ)by means of a two-step fermentation method which were independently performed first by Arthrobacter and next by Abslaia, and 2)the product was obtained by a sequential fermentation system of aforesaid two micro-organisms in a single fermentor without isolation of the intermediates from the mixture. Our results showed that in both fermentation systems high yield of product was obtained. However, according to the technical simplicity, shorter duration of fermentation cycle and efficient yield of product, the second method is better than the first one.     

Crystal structures of native and inactivated cis-3-chloroacrylic acid dehalogenase. Structural basis for substrate specificity and inactivation by (R)-oxirane-2-carboxylate

The bacterial degradation pathways for the nematocide 1,3-dichloropropene rely on hydrolytic dehalogenation reactions catalyzed by cis- and trans-3-chloroacrylic acid dehalogenases (cis-CaaD and CaaD, respectively). X-ray crystal structures of native cis-CaaD and cis-CaaD inactivated by (R)-oxirane-2-carboxylate were elucidated. They locate four known catalytic residues (Pro-1, Arg-70, Arg-73, and Glu-114) and two previously unknown, potential catalytic residues (His-28 and Tyr-103'). The Y103F and H28A mutants of these latter two residues displayed reductions in cis-CaaD activity confirming their importance in catalysis. The structure of the inactivated enzyme shows covalent modification of the Pro-1 nitrogen atom by (R)-2-hydroxypropanoate at the C3 position. The interactions in the complex implicate Arg-70 or a water molecule bound to Arg-70 as the proton donor for the epoxide ring-opening reaction and Arg-73 and His-28 as primary binding contacts for the carboxylate group. This proposed binding mode places the (R)-enantiomer, but not the (S)-enantiomer, in position to covalently modify Pro-1. The absence of His-28 (or an equivalent) in CaaD could account for the fact that CaaD is not inactivated by either enantiomer. The cis-CaaD structures support a mechanism in which Glu-114 and Tyr-103' activate a water molecule for addition to C3 of the substrate and His-28, Arg-70, and Arg-73 interact with the C1 carboxylate group to assist in substrate binding and polarization. Pro-1 provides a proton at C2. The involvement of His-28 and Tyr-103' distinguishes the cis-CaaD mechanism from the otherwise parallel CaaD mechanism. The two mechanisms probably evolved independently as the result of an early gene duplication of a common ancestor.     

Satellite tracking of two Montagu’s Harriers (Circus pygargus): dual pathways during autumn migration

Autumn migration routes of two Dutch female Montagu’s Harriers (Circus pygargus) were documented for the first time using satellite telemetry. Both migrated to their African wintering area—one via the Straits of Gibraltar through the Mediterranean and the other via Italy/Tunisia. The rate of travel was comparable to values reported for larger raptor species.     

MCA/MR syndrome in two female siblings: new entity or variant examples of Coffin-Lowry versus Atkin-Flaitz syndromes?

We report two sisters with mental retardation, coarse facial features, telecanthus, flat malar region, prominent lower lip, kyphoscoliosis, and tapering fingers. Although these patients' phenotypes showed considerable overlap with the Coffin-Lowry and the Atkin-Flaitz syndromes, their overall picture makes these diagnoses controversial.     

The effect of physical, social and psychological factors on drug compliance in patients with mild hypertension

Background. In patients with hypertension noncompliance with drug treatment is between 15 to 54%, and has been recognised as a relevant contributor to the burden of cardiovascular morbidity. Up to 92% of patients experience unpleasant symptoms with their condition and, particularly in these patients, the symptoms experienced may enhance compliance. Objective. To simultaneously assess the effects of physical, social and psychological factors on noncompliance. Methods. Patients with mild hypertension despite drug treatment, from the departments of cardiology and internal medicine, were requested to answer a self-administered questionnaire addressing the presence of physical symptoms as well as psychosocial factors. The questionnaire was based on previously used test batteries and consisted of two lists of physical complaints and four lists addressing the four domains of planned behaviour regarding medical non-adherence according to Baron and Byrne. These domains mainly assess psychosocial factors. Each list consisted of three or more items and each item was scored on fiveto seven-point scales. Mean scores were used for assessment. The lists were also separately assessed for internal consistency and reliability using Cronbach’s alphas. One-way analysis of variance and multivariate analysis of variance (MANOVA) with compliance as outcome variable and the physical, social and psychological variables as indicator variables were used for data analysis. MANOVA was adjusted for multiple testing. Results. Many patients experienced physical symptoms due to hypertension, such as tiredness (31%), hot flushes (28%), headache (24%), reduced daily life energy (23%), palpitations (22%), with 95% confidence intervals between 16 to 38%. Scores for physical symptoms and social factors did not differ between self-reported adherers (n=165) and nonadherers (n=11). However, the score for psychological factors was significantly larger in the adherers than in the non-adherers, 5.05 versus 3.06, p<0.018. The MANOVA showed a significant overall difference between the adherers and non-adherers in the data at p<0.012, which was mainly due to the score for psychological factors. Conclusion. The effect of physical symptoms on non-compliance in mildly hypertensive patients is negligible. So is the effect of social factors. Psychological factors such as lacking a sense of guilt, regret and shame are major determinants of non-compliance. Physicians may play an educational role in improving their patients’ compliance by addressing these determinants. We should add that the conclusions should be made with reservations, given the small number of non-adherers in our sample. (Neth Heart J 2008;16:197-200.)