Diversity of soil cellulase isoenzymes is associated with soil cellulase kinetic and thermodynamic parameters

This study was conducted to determine how land management in three ecosystems including forest, rangeland, and saline desert soils affects the activity and diversity of isoenzymes, and the kinetic and thermodynamic parameters of soil cellulase. Cellulase was chosen because it hydrolyzes cellulose, a major plant substance entering the soils. Soil samples were collected in October 2009 from a native forest, a native rangeland, and a native saline desert as well as adjacent cultivated fields in central Iran. Land use changes of the native forest, rangeland, and saline desert soils resulted in 79%, 47%, and 73% reductions in cellulase activity, respectively. The Michaelis constant (K_m) increased but the maximum catalytic velocity (V_max) decreased for soil cellulase as a result of cultivation in the study areas. The thermodynamic parameters (E_a and Q₁₀) of soil cellulase were also affected by cultivation. Higher E_a and Q₁₀ values were obtained for the native soils, but the lower values belonged to the cultivated soils. The cellulase zymographic pattern revealed different cellulase isoenzymes in the soils. The prevailing cellulase isoenzymes in the soils were found to have molecular weights of 62 and 74 kDa in the native forest, 86 kDa in the cultivated forest, 55 and 65 kDa in the native rangeland, and 72 kDa in the reclaimed saline areas. Evidence reveals that the sensitivity of soil cellulase kinetic and thermodynamic parameters to land management seems to be due to differences in the cellulase isoenzymes present in soils.     

A comparison of retrobulbar and two peribulbar regional anesthetic techniques in dog cadavers

Objective

To compare injectate distribution and likelihood of regional anesthesia to the orbit following retrobulbar (RB) or peribulbar (PB) injections in dog cadavers.

Relationship of plasma calcium and phosphorus to the shell quality of laying hens receiving saline drinking water

1. From 36 to 43 weeks of age 210 White Leghorn laying hens were used to study the relationship of plasma calcium and phosphorus concentrations to egg‐shell quality when saline drinking water was given.

2. Seven experimental treatments in which different amounts of sodium chloride were supplied by the food and/or the drinking water were compared.

3. Increasing salt intake through the drinking water or the food reduced shell thickness and shell calcium, and increased the numbers of damaged eggs. Sodium chloride given in the drinking water was more effective in reducing shell quality and increasing plasma calcium and phosphorus than sodium chloride given in the food.     

Season-induced changes in bovine sperm motility following a freeze-thaw procedure

Decreased conception rate of dairy cows in the summer is mainly associated with the deleterious effects of environmental thermal stress on the female reproductive tract. Here, we suggest that decreased reproductive performance might be partially due to inferior-quality semen. Semen from five representative bulls was collected in summer (August to September) and winter (December to January) and evaluated with a computerized sperm-quality analyzer for bulls (SQA-Vb). No seasonal effect was found in fresh ejaculate, but sperm examined post-thawing showed lower velocity, motility and progressive motility (P<0.04) in summer vs. winter samples. Element concentrations in the seminal plasma, determined by inductively coupled plasma-atomic emission spectrometry, differed between seasons, with higher (P<0.01) concentration values of K, Mg, Na and S elements in winter vs. summer samples. Therefore, season-induced alterations in seminal plasma element concentration should be taken into account when using an extender for cryopreservation. Acrosome integrity was assessed by a triple-fluorescence test using Hoechst 33342, fluorescein isothiocyanate-conjugated Pisum sativum agglutinin (FITC-PSA) and propidium iodide. Acrosome reaction was examined by a one-step staining method using FITC-PSA. The proportion of sperm cells with a damaged acrosome post-thawing tended to be higher (P<0.07) in semen collected during the summer vs. winter. Such alterations suggest that seasonal reductions in sperm function might also be involved in the decreased conception rate of dairy cows in summer.     

肉鸡舍的最佳气候条件与通风方式

近30年来,全球的家禽业获得了长足的发展.其中的许多成就来源于对肉鸡快速生长和理想饲料报酬的选育.目前,肉鸡在42日龄的体重要比10年前高出0.45千克.遗传学家和大型肉鸡场已把最大的重点放在进一步提高肉鸡的生长率、饲料报酬和胸肉产量上.他们估计到2005年,肉用仔鸡在28日龄时体重可达到1.8千克.但只有在生产者放弃传统的饲养系统,采用现代饲养技术,使肉鸡的饲养环境和管理达到最佳水平才能取得这些遗传进展.在获取肉鸡最佳生产性能的许多变量中,最重要的因子之一是通过正确通风获取较好的空气质量.     

Model projections of an imminent transition to a more arid climate in southwestern North America

How anthropogenic climate change will affect hydroclimate in the arid regions of southwestern North America has implications for the allocation of water resources and the course of regional development. Here we show that there is a broad consensus among climate models that this region will dry in the 21st century and that the transition to a more arid climate should already be under way. If these models are correct, the levels of aridity of the recent multiyear drought or the Dust Bowl and the 1950s droughts will become the new climatology of the American Southwest within a time frame of years to decades.     

Standard and modified glabellar flap for medial canthus reconstruction following mass removal in three dogs and two cats

Purpose

To describe the surgical technique and clinical outcomes of the glabellar flap and its modification for the reconstruction of the medial canthus following resection of tumors in three dogs and two cats.

Methods

Three dogs (7-, 7-, and 12.5-year-old mixed breeds) and two cats (10- and 14-year-old Domestic shorthair) presented with a 7–13 mm tumor affecting the eyelid and/or conjunctiva in the medial canthal region. Following en bloc mass excision, an inverted V-shaped skin incision was made in the glabellar region (i.e., the area between the eyebrows in humans). The apex of the inverted V-shaped flap was rotated in three cases, whereas a horizontal sliding movement was performed in the other two cases to better cover the surgical wound. The surgical flap was then trimmed to fit the surgical wound and sutured in place in two layers (subcutaneous and cutaneous).

Results

Tumors were diagnosed as mast cell tumors (n = 3), amelanotic conjunctival melanoma (n = 1), and apocrine ductal adenoma (n = 1). No recurrence was noted in a follow-up time of 146 ± 84 days. Satisfactory cosmetic outcome with normal eyelids closure was achieved in all cases. Mild trichiasis was present in all patients and mild epiphora was noted in 2/5 patients, but there were no associated clinical signs such as discomfort or keratitis.

Conclusions

The glabellar flap was easy to perform and provided a good outcome in terms of cosmetic, eyelid function, and corneal health. Postoperative complications from trichiasis appear to be minimized by the presence of the third eyelid in this region.     

Impact of DNA damage on the frequency of sperm chromosomal aneuploidy in normal and subfertile men

Background: Various frequencies of sperm aneuploidy are reported in sperms of subfertile patients compared to normal individuals. Moreover, sperm DNA damage is shown to be associated with male infertility. In this study, the rate of DNA damage and frequencies of aneuploidy in sperms of subfertile patients was investigated. Methods: Semen samples were obtained from healthy normal and subfertile (oligozoospermia, asthenozoospermia, and oligoasthenozoospermia) men. The frequency of aneuploidy was assessed using primed in situ labeling (PRINS) analysis with specific primers for chromosomes 18, 21, X, and Y. Sperm DNA damage was assessed using alkaline comet assay. Results: The mean frequencies of disomy for the patients were significantly higher than normal for all chromosomes (P<0.01). The extent of DNA damage in sperms of subfertiles was significantly higher than in normal individuals (P<0.001). The obtained results indicated that higher rate of DNA damages led to higher frequency of chromosomal disomy except for asthenozoospermia samples which exhibited higher rate of DNA damage and lower frequency of chromosomal disomy. Conclusions: These results demonstrate that men with oligozoospermia and oligoasthenozoospermia have an elevated risk for chromosome abnormalities in their sperm, particularly sex chromosomes. DNA damage might be involved in the process of malsegregation of chromosomes.Asthenozoospermia, DNA damage, Primed in situ labeling (PRINS), Comet assay