Isolation of Mycobacterium species from raw milk of pastoral cattle of the Southern Highlands of Tanzania

A study to determine the secretion of Mycobacterium spp. in milk from indigenous cattle was carried out in pastoral cattle reared in the Southern Highlands of Tanzania. The study was aimed at elucidating the dangers associated with milk-borne zoonoses in a society where milk is normally consumed raw. Out of 805 milk samples, 31 (3.9%) were positive for mycobacteria. There was a preponderance of atypical mycobacteria (87%) whereas only two isolates (6.5%) were confirmed as M. bovis. Atypical mycobacteria included: M. terrae (n=7), M. fortuitum (n=2), M. flavescens (n=13), M. gordonae (n=1) and M. smegmatis (n=4). Although the number of M. bovis positive samples was low, the habit of pooling milk may still pose great public health dangers to milk consumers in this part of the world. Moreover, isolation of atypical mycobacteria should also be considered to be a danger to human health in countries such as Tanzania, where the number of people with lowered immunity due to HIV infection is on the increase.     

Hiatal herniation as a complication of chronic diaphragmatic herniation

Three of four cases of chronic diaphragmatic herniation seen over a period of 12 months developed hiatal herniation within five to eight days of corrective surgery for the diaphragmatic herniation. None of the dogs had shown any prior signs referrable to hiatal herniation. The features that developed subsequent to diaphragmatic herniorrhaphy in all cases were dyspnoea, increased intra-abdominal pressure due to decreased abdominal domain and laxity of the oesophageal hiatus as judged subjectively at the time of surgery for hiatal herniation correction. These conditions may be significant underlying factors for the development of hiatal herniation not preceded by diaphragmatic herniation in the dog. Those associated factors accepted as important in humans, including reduced lower oesophageal sphincter tone and gastroesophageal reflux, may not be of similar importance in small animals.     

Herpesvirus cyprini: lethality and oncogenicity

Abstract. Cyprinid herpesvirus 1 (CHV) or Herpesvirus cyprini was virulent for carp, Cyprinus carpio L., fry following 1 h immersion in water at 20 °C. Cumulative mortality for carp fry was 86–97% in 2-week-old common carp, 20% in 4-week-old fancy carp, and 0% in both 8-week-old common and fancy carp. The virus did not produce mortality in fry of crucian carp, grass carp or other cyprinids. It was also oncogenic in carp, inducing papillomas to the extent of 55% among both common and fancy carp fry. The neoplasms appeared 5–6 months after carp had been exposed to the virus by immersion and recurred at an incidence of 83% in carp 7·5 months post-desquamation of the tumour. The CHV was reisolated from all moribund fish and from all survivors. It also induced papillomas at an incidence of 13% in adult mirror carp and at 10% in adult fancy carp 5 months after intraperitoneal inoculation of 10⁵ TCID₅₀ ml^-1 fish. The virus was rcisolated only from the ncoplastic tissue and not from internal organs. The neoplasms were normally located on fin, skin or mandible, at the intraperitoneal inoculation site. Specific fluorescence for CHV antigen was frequently detected in the gills, liver, kidneys and intestine of 2-week-old fry from 3 to 21 days following challenge with CHV. It was found in greater concentrations in experimentally induced papillomata on 2-week-old carp fry survivors examined 24 weeks after challenge than in naturally occurring neoplasms.     

Effect of pH on nitrogen mineralization in crop-residue-treated soils

Summary This study compares N mineralization in soils treated with crop residues [corn (Zea mays L.), soybean (Glycine max (L.) Merr.), sorghum (Sorghum vulgare Pers.)] or alfalfa (Medicago sativa L.) at three adjusted soil pH values (4, 6, and 8); pH was adjusted with dilute H₂SO₄ or KOH. A sample of soil (20 g) was treated with 0.448 g plant material (equivalent to 50t ha^–1), mixed with 20 g silica sand adjusted to the pH of the soil, and packed in a leaching tube. The soil-sand mixture was leached with 100 ml 5 mM CaCl₂ adjusted to the same pH as that of the treated soil to remove the initial mineral N, and incubated at 30°C. The leaching procedure was repeated every 2 weeks for 20 weeks. Results from three soils showed that N mineralization increased as the soil pH increased. In one soil (Lester soil), significant amounts of NH ₄ ⁺ -N accumulated at pH 4 during the first 12 weeks. Treatment with corn and soybean residues resulted in a marked reduction in N mineralization, especially at pH 4. The percentage of organic N mineralized from sorghum residue and alfalfa added to soils increased as the soil pH increased; the values ranged from 7.7% to 37.0% for sorghum and from 17.2% to 30.1% for alfalfa.     

Liming and Manganese Foliar Levels in Orange

ABSTRACT

Citrus cultures have a fundamental importance to the Brazilian economy; certain aspects such as plant nutrition, yield, and fruit quality are vital for the citrus industry sustainability. The present study evaluated the nutritional status of manganese in adult Pear orange trees using different lime rates topically applied to the soil. The direct evaluation of lime rates effects on leaf manganese (Mn) levels revealed a decrease of the nutrient correlated to its increased, as well as passage of time between application and measurement. Foliar sampling 30 months after surface lime application evidenced a high correlation of foliar manganese levels with soil base saturation of 10–20 cm. Leaf manganese levels which showed a great probability of high productivity were between 33 and 70 mg kg^?1.     

高等植物成花的生理生化与分子机制研究进展

成花过程是高等植物生长发育过程中最重要的阶段之一,包括一系列生理生化代谢与基因调控反应。本文对高等植物成花过程中生理生化与分子机制的研究进行了综述,并介绍了miRNA在植物成花过程中的作用,为成花研究提供参考。     

Telomere length and telomerase activity in canine mammary gland tumors

OBJECTIVE: To measure telomere length and telomerase activity in naturally occurring canine mammary gland tumors. SAMPLE POPULATION: 27 mammary gland tumor specimens obtained during resection or necropsy and 12 mammary gland tissue specimens obtained from healthy (control) dogs. PROCEDURE: Telomere length in tissue specimens was measured by use of restriction endonuclease digestion and Southern blot analysis. Telomerase activity was measured by use of a telomeric repeat amplification protocol assay. RESULTS: Telomere length in mammary gland tumors ranged from 11.0 to 21.6 kilobase pairs (kbp; mean +/- SEM, 14.5+/-0.5 kbp) but did not differ among tumor types. Telomeres in mammary gland tumors were slightly shorter than in normal tissue specimens, but telomere length could not be directly compared between groups, because mean age of dogs was significantly different between groups. Age was negatively correlated with telomere length in control dogs but was not significantly correlated with length in affected dogs. Telomerase activity was detected in 26 of 27 mammary gland tumors and in 4 of 12 normal tissue specimens. However, telomerase activity and telomere length were not correlated in tumor specimens. CONCLUSIONS AND CLINICAL RELEVANCE: Telomere length is maintained in canine mammary gland tumors regardless of the age of the affected dog. Measurement of telomere length may be a useful tool for monitoring the in vivo effects of telomerase inhibitors in dogs with tumors.     

In vitro reactivity of digital arteries and veins to vasoconstrictive mediators in healthy horses and in horses with early laminitis

The in vitro reactivity of vasoconstrictive mediators that are implicated in acute laminitis was determined in palmar and plantar digital arteries and veins obtained from healthy horses and in palmar digital vessels of horses with early laminitis (Obel grade I). To obtain baseline reactivity data, 3 experiments were conducted, using healthy horses: (1) the reactivity of palmar and plantar digital arteries and veins to angiotensin II, norepinephrine, and 5-hydroxytryptamine (serotonin) were compared; (2) the direct effects of bacterial endotoxin on vascular reactivity were assessed; and (3) the reactivity of palmar digital arteries and veins to angiotensin II, norepinephrine, prostaglandin F2 alpha (PGF2 alpha), serotonin, and a thromboxane-endoperoxide analog (U46619) were determined. The vascular reactivity of these same 5 vasoconstrictors then was determined in horses with early laminitis and was compared with data from healthy (control) horses. Obel grade-I laminitis was experimentally induced in horses, using carbohydrate overload. Dose responses were conducted for each agent at concentrations between 10(-8)M and 10(-4)M. The potency of a drug was defined as the mean effective concentration necessary to induce 50% of maximal contraction (EC50). There were no differences in EC50 concentrations and in maximal contractions between forelimb and hind limb arteries and veins for angiotensin II, norepinephrine, and serotonin. Incubation with endotoxin had no effect on the reactivity of arteries and veins to angiotensin II, norepinephrine, and serotonin.(ABSTRACT TRUNCATED AT 250 WORDS)