Oxidative stress drives divergent evolution of the glutathione peroxidase (GPX) gene family in mammals

The molecular basis for adaptations to extreme environments can now be understood by interrogating the ever-increasing number of sequenced genomes. Mammals such as cetaceans, bats, and highland species can protect themselves from oxidative stress, a disruption in the balance of reactive oxygen species, which results in oxidative injury and cell damage. Here, we consider the evolution of the glutathione peroxidase (GPX) family of antioxidant enzymes by interrogating publicly available genome data from 70 mammalian species from all major clades. We identified 8 GPX subclasses ubiquitous to all mammalian groups. Mammalian GPX gene families resolved into the GPX4/7/8 and GPX1/2/3/5/6 groups and are characterized by several instances of gene duplication and loss, indicating a dynamic process of gene birth and death in mammals. Seven of the eight GPX subfamilies (all but GPX7) were under positive selection, with the residues under selection located at or close to active sites or at the dimer interface. We also reveal evidence of a correlation between ecological niches (e.g. high oxidative stress) and the divergent selection and gene copy number of GPX subclasses. Notably, a convergent expansion of GPX1 was observed in several independent lineages of mammals under oxidative stress and may be important for avoiding oxidative damage. Collectively, this study suggests that the GPX gene family has shaped the adaption of mammals to stressful environments.     

Feeding Saccharomyces cerevisiae fermentation products lessens the severity of a viral–bacterial coinfection in preweaned calves

We have previously reported that supplementation with Saccharomyces cerevisiae fermentation products (SCFP) ameliorates clinical signs and lung pathology following experimental bovine respiratory syncytial virus (BRSV) infection in preweaned dairy calves. The objectives of this study were to determine the effect of SCFP supplementation on the metabolic and endocrine responses, and disease outcome of a viral–bacterial coinfection in preweaned calves. Twenty-seven, 1- to 2-d-old Holstein-Angus cross calves were enrolled in the study; one SCFP calf was removed from the trial during the pre-challenge phase due to complications from nephritis. Calves were assigned to two treatment groups: control or SCFP-treated, base milk replacer with 1 g/d SCFP (Smartcare, soluble formula) and calf starter top dressed with 5 g/d SCFP (NutriTek, insoluble formula). Calves were infected with BRSV on day 21, followed 6 d later by intratracheal inoculation with Pasteurella multocida (PM). Calves were euthanized on day 10 post-viral infection. Calves receiving SCFP had reduced thoracic ultrasonography scores on day 7 post-viral infection (P = 0.03) and a tendency toward reduced scores on day 10 post-viral infection (P = 0.09). Calves receiving SCFP also had less severe lung pathology scores at necropsy (P = 0.06). No differences between treatments were observed in lung viral loads (P = 0.48) or bacterial lung recovery (P = 0.34); however, there was a distinction in the lung location for PM recovery, with PM isolated more frequently from the cranial lobes in SCFP-treated calves, but more frequently from the caudal lobes of control calves. Calves treated with SCFP tended (P = 0.07) to have higher serum IL-6 concentrations following the coinfection. Calves treated with SCFP had lower concentrations of serum nonesterified fatty acids and beta-hydroxybutyric acid compared with controls following experimental challenge (P = 0.03 and P = 0.08, respectively), suggesting metabolic changes favoring growth and development. There were no differences between groups in gene expression of insulin receptor, insulin-like growth factor 1 (IGF-1), IGF-1 receptor (IGF-1R), growth hormone receptor, or haptoglobin in the liver. Results from this study suggest that supplementing with SCFP may moderate the impact of a respiratory viral–bacterial coinfection on preweaned calves through metabolic and immune modifications.     

Weather-Centric Rangeland Revegetation Planning

Invasive annual weeds negatively impact ecosystem services and pose a major conservation threat on semiarid rangelands throughout the western United States. Rehabilitation of these rangelands is challenging due to interannual climate and subseasonal weather variability that impacts seed germination, seedling survival and establishment, annual weed dynamics, wildfire frequency, and soil stability. Rehabilitation and restoration outcomes could be improved by adopting a weather-centric approach that uses the full spectrum of available site-specific weather information from historical observations, seasonal climate forecasts, and climate-change projections. Climate data can be used retrospectively to interpret success or failure of past seedings by describing seasonal and longer-term patterns of environmental variability subsequent to planting. A more detailed evaluation of weather impacts on site conditions may yield more flexible adaptive-management strategies for rangeland restoration and rehabilitation, as well as provide estimates of transition probabilities between desirable and undesirable vegetation states. Skillful seasonal climate forecasts could greatly improve the cost efficiency of management treatments by limiting revegetation activities to time periods where forecasts suggest higher probabilities of successful seedling establishment. Climate-change projections are key to the application of current environmental models for development of mitigation and adaptation strategies and for management practices that require a multidecadal planning horizon. Adoption of new weather technology will require collaboration between land managers and revegetation specialists and modifications to the way we currently plan and conduct rangeland rehabilitation and restoration in the Intermountain West.     

The activity and expression of chitinase in the equine lung and its activity in normal horses and animals with recurrent airway obstruction

Recurrent airway obstruction (RAO) is a chronic inflammatory condition in equine lung, which may share a common immunological basis with human asthma, in which dysregulated Th2 responses occur. Mammals express chitinases and chitinase-like proteins, two of which are active enzymes, chitotriosidase and acidic mammalian chitinase (AMCase). Both enzymes are upregulated in a range of inflammatory conditions, including asthma. We investigated the activity of chitinase in bronchoalveolar lavage fluid from horses with and without RAO in response to organic dust challenges. No significant differences were found in activity, although in one study RAO animals had elevated chitinase activity that fell short of statistical significance. The pH optimum and pH lability of the activity was consistent with the presence of chitotriosidase. RT-PCR amplification of the mRNA encoding chitotriosidase and AMCase in normal equine lung showed that chitotriosidase, but not AMCase, is expressed in trachea, bronchi, and peripheral lung tissue. The gene for chitotriosidase was identified from the Equus caballus (horse) genome 1.1 database and its similarity to the same genes from other species was determined. The results of this study indicate that the involvement of chitotriosidase in RAO is uncertain.     

Enhancing mucosal immunity in mice by recombinant adenovirus expressing major epitopes of porcine circovirus-2 capsid protein delivered with cytosine-phosphate-guanosine oligodeoxynucleotides

A recombinant replication-defective adenovirus expressing the major epitopes of porcine circovirus-2 (PCV-2) capsid protein (rAd/Cap/518) was previously constructed and shown to induce mucosal immunity in mice following intranasal delivery. In the present study, immune responses induced by intranasal immunization with a combination of rAd/Cap/518 and cytosine-phosphate-guanosine oligodeoxynucleotides (CpG ODN) were evaluated in mice. The levels of PCV-2-specific IgG in serum and IgA in saliva, lung, and intestinal fluids were significantly higher in the group immunized with rAd/Cap/518 and CpG ODN than animals immunized with rAd/Cap/518 alone. The frequencies of IL-2-secreting CD4⁺ T cells and IFN-γ-producing CD8⁺ T cells were significantly higher in the combined immunization group than mice immunized with rAd/Cap/518 alone. The frequencies of CD3⁺, CD3⁺CD4⁺CD8^-, and CD3⁺CD4^-CD8⁺ T cells in the combined immunization group were similar to that treated with CpG ODN alone, but significantly higher than mice that did not receive CpG ODN. PCV-2 load after challenge in the combined immunization group was significantly lower than that in the phosphate-buffered saline placebo group and approximately 7-fold lower in the group treated with CpG ODN alone. These results indicate that rAd/Cap/518 combined with CpG ODN can enhance systemic and local mucosal immunity in mice, and represent a promising synergetic mucosal vaccine against PCV-2.     

疑核内有关神经元在机体细胞免疫调节中的作用

研究了疑核内胆碱能神经元、去甲肾上腺素能神经元、脑啡肽能神经元对机体细胞免疫机能的影响 ,并对疑核内 3种神经元之间的相互关系进行了探讨。实验用麻醉家兔 ,分 6组进行 ,分别在疑核处通过微量注射器注入氯化乙酰胆碱 ( Ach)、密胆碱 -3( HC-3)、酒石酸去甲肾上腺素 ( NA)、6-羟基多巴胺 ( 6-OHDA)、盐酸吗啡 ( MP)、盐酸纳络酮 ( NX) ,并分别于注射前和注射后不同时间取外周血 ,测定 T细胞百分率及PHA诱导的有丝分裂原反应。结果 :Ach组上述免疫指标比注射前明显升高 ;HC-3组上述免疫指标比注射前明显降低 ;NA组上述免疫指标在注射后 30、60 min时明显低于注射前 ;6-OHDA组上述免疫指标在注射后 1 0～ 1 2 0 min时明显升高 ;MP组上述免疫指标在注射后 60、1 2 0 min时明显降低 ;NX组上述免疫指标注射前、后无明显变化。提示 :疑核增强机体细胞免疫的作用可能是通过胆碱能神经元实现的 ;疑核内的去甲肾上腺素能神经元与胆碱能神经元的作用相拮抗 ;而疑核内的脑啡肽能神经元可能对前两者的活动起一种调整作用     

Streptococcus Suis: Past and Present

Staats, J.J., Feder, I., Okwumabua, O. and Chengappa, M.M., 1997. Streptococcus suis: past and present. Veterinary Research Communications, 21 (6), 381-407Steptococcus suis is a Gram-positive, facultatively anaerobic coccus that has been implicated as the cause of a wide range of clinical disease syndromes in swine and other domestic animals. In swine, the disease has spread worldwide but is more prevalent in countries with intensive swine management practices. The disease syndromes caused by S. suis in swine include arthritis, meningitis, pneumonia, septicaemia, endocarditis, polyserositis, abortions and abscesses. S. suis has also been implicated in disease in humans, especially among abattoir workers and swine and pork handlers. In humans, S. suis type 2 can cause meningitis, which may result in permanent hearing loss, septicaemia, endocarditis and death. The pathogenic mechanism of S. suis is not well defined. Several virulence factors have been identified, but their roles in pathogenesis and disease have not been well elucidated. Much work is in progress on characterization of virulence factors and mechanisms, with emphasis on the control of the disease. Because of the non-availability of suitable immunoprophylaxis, control of S. suis infection has depended mainly on the use of antimicrobials.     

Infectious bovine keratoconjunctivitis: Bacteriologic,immunologic, and clinical responses of cattle to experimental exposure with Moraxella bovis

The bacteriologic, immunologic, and clinical responses of 3- to 4-month old Holstein-Friesian calves to experimental exposure with Moraxella bovis type 10900 has been investigated. After u.v. radiation and intraconjunctival exposure with 1.9 × 10⁷ microorganisms, each eye of 16 calves exhibited signs of blepharospasm, photophobia, and increased lacrimation. Bacteria were recovered from exposed eyes for 2–7 consecutive weeks before maximal clinical response occurred. The severity of the cases varied from eyes that exhibited mild signs to severe clinical cases with profuse lacrimation, conjunctival swelling, corneal opacity, and ulceration. By 70 days after exposure, M. bovis could not be recovered from any conjunctival swabs, and clinical signs were not observed. Four non-exposed control animals did not develop clinical signs nor was M. bovis recovered from conjunctival swabs.Lacrimal secretions collected at the time of and 1 week after maximal clinical response had significantly elevated levels of total protein as compared to those collected 3, 2, and 1 week before, and 2 and 3 weeks after maximal clinical response. A passive hemagglutination test, using tanned formalized sheep erythrocytes sensitized with M. bovis sonicate antigen, detected antibody in lacrimal secretions from 22 of 32 eyes. The appearance of specific antibody in lacrimal secretions correlated with the amelioration of clinical signs and the decline in numbers of M. bovis microorganisms recovered from conjunctival swabs.     

Genetic immunization with the immunodominant antigen P48 of Mycoplasma agalactiae stimulates a mixed adaptive immune response in BALBc mice

A DNA vaccine against contagious agalactia was developed for the first time, encoding the P48 of Mycoplasma agalactiae. Specific immune responses elicited in BALB/c mice were evaluated. Both total IgG and IgG1 were detected in mice vaccinated with pVAX1/P48. Proliferation of mononuclear cells of the spleen, levels of gamma interferon, interleukin-12, and interleukin-2 mRNAs were enhanced in immunized animals. Results indicate that pVAX1/P48 vaccination induced both T_h1 and T_h2 immune responses. Nucleic acid immunization could be a new strategy against M. agalactiae infections and may be potentially used to develop vaccines for other Mycoplasma diseases.     

励珂健喷剂对10日龄内仔猪腹泻和免疫力的影响

为研究励珂健喷剂（主要成分：杨树花提取物）对10日龄内仔猪腹泻和免疫力的影响,将18头PIC母猪随机分成3组,每组6头,分别为蒸馏水组、土霉素组和励珂健喷剂组,蒸馏水组仔猪1、3、5日龄时皮肤喷洒蒸馏水1 m L/头/d,土霉素组仔猪3、7日龄时分别肌肉注射20%长效土霉素注射液0.2 m L/头/d、0.5m L/头/d,励珂健喷剂组仔猪1、3、5日龄时皮肤喷洒励珂健喷剂1 m L/头/d。结果表明,励珂健喷剂可有效降低10日龄内仔猪的腹泻率和发病率,且励珂健喷剂组腹泻仔猪的治愈速度快于土霉素组和蒸馏水组。由此证明：励珂健喷剂对10日龄内仔猪腹泻有防治作用,并且还可以增强仔猪的免疫力。