Symbiotic efficiency of Rhizobium leguminosarum sv. trifolii strains originating from the subpolar and temperate climate regions

Red clover (Trifolium pratense L.) is a forage legume cultivated worldwide. This plant is capable of establishing a nitrogen-fixing symbiosis with Rhizobium leguminosarum symbiovar trifolii strains. To date, no comparative analysis of the symbiotic properties and heterogeneity of T. pratense microsymbionts derived from two distinct geographic regions has been performed. In this study, the symbiotic properties of strains originating from the subpolar and temperate climate zones in a wide range of temperatures (10-25 °C) have been characterized. Our results indicate that all the studied T. pratense microsymbionts from two geographic regions were highly efficient in host plant nodulation and nitrogen fixation in a wide range of temperatures. However, some differences between the populations and between the strains within the individual population examined were observed. Based on the nodC and nifH sequences, the symbiotic diversity of the strains was estimated. In general, 13 alleles for nodC and for nifH were identified. Moreover, 21 and 61 polymorphic sites in the nodC and nifH sequences were found, respectively, indicating that the latter gene shows higher heterogeneity than the former one. Among the nodC and nifH alleles, three genotypes (I-III) were the most frequent, whereas the other alleles (IV-XIII) proved to be unique for the individual strains. Based on the nodC and nifH allele types, 20 nodC-nifH genotypes were identified. Among them, the most frequent were three genotypes marked as A (6 strains), B (5 strains), and C (3 strains). Type A was exclusively found in the temperate strains, whereas types B and C were identified in the subpolar strains. The remaining 17 genotypes were found in single strains. In conclusion, our data indicate that R. leguminosarum sv. trifolii strains derived from two climatic zones show a high diversity with respect to the symbiotic efficiency and heterogeneity. However, some of the R. leguminosarum sv. trifolii strains exhibit very good symbiotic potential in the wide range of the temperatures tested; hence, they may be used in the future for improvement of legume crop production.

Impact of Protoporphyrin Lysine Derivatives on the Ability of Nosema ceranae Spores to Infect Honeybees

Simple Summary

Honeybees, which are important for the development and maintenance of natural ecosystems, are infected by microsporidia, Nosema apis and N. ceranae. These parasites induce a disease named nosemosis contributing to the impairment of digestion and nutrient absorption, ultimately leading to total colony collapse. The need for research into the control of N. ceranae has become increasingly important. Promising compounds for the treatment of nosemosis are porphyrins. In the present study, we examined the effects of three different porphyrins on the infectivity of N. ceranae microsporidia. A significantly lower level of infection was observed in the bees infected with the porphyrin-treated spores than in the control bees (infected with untreated spores). We showed that protoporphyrin lysine derivatives in particular prevented the development of Nosema spores and simultaneously extended bee life spans (up to 50%). The results also indicate that these porphyrins may contribute to the reduction in digestive nutrient absorption disorders in bees. The present findings can be used to develop a new class of drugs for combating nosemosis. These compounds may serve as preventive or disinfection agents through direct inactivation of Nosema both in the midgut and outside the host body, i.e., in the hive.

Abstract

The effect of two protoporphyrin IX derivatives conjugated with single (PP[Lys(TFA)-OH)]₂) or double (PP[Lys(TFA)-Lys(TFA)-OH]₂) lysine moieties on the infectious capacity of Nosema ceranae spores was examined, and their efficacies were compared with those of a cationic porphyrin (H₂TTMePP). Honeybees were inoculated with spores preincubated with porphyrins or with untreated spores (control). A significantly lower level of infection was observed in the bees infected with the porphyrin-treated spores than in the infected control. Porphyrins 1 and 2 reduced the infectious capability of microsporidia more efficiently than porphyrin 3, with bee mortality declining to almost 50%. Confocal analysis of the midguts of infected bees revealed distinct differences in the number of spores between the control group and the group infected with PP[Lys(TFA)-Lys(TFA)-OH]₂-treated spores. Notably, bees with a reduced level of infection consumed less sucrose syrup than the control bees, indicating a reduction in digestive disorders and an improvement in food absorption.

Bioactivity studies of porphyrinoids against microsporidia isolated from honeybees

Microsporidian infections are dangerous to honeybees due to the absence of an efficient treatment for nosemosis. In the present work, the abilities of several porphyrins to directly inactivate microsporidia derived from Nosema-infected honeybees were studied in vitro. Amide derivatives of protoporphyrin IX (PPIX) conjugated with one and two amino acid moieties were synthesized, and their activities were compared with those of two cationic porphyrins, TMePyP and TTMePP. The most active porphyrins, PP[Lys-Asp]₂, PP[Lys-TFA]₂, PP[Asp(ONa)₂]₂ and PP[Lys-Lys]₂ at concentrations as low as 10–50 µM exerted significant effects on microsporidia, reducing the number of spores by 67–80% compared to the control. Live-cell imaging of the spores treated with porphyrins showed that only 1.6% and 3.0% of spores remained alive after 24 h-incubation with 50 µM PP[Asp(ONa)₂]₂ and PP[Lys-Asp]₂, respectively. The length of the amino acid side chains and their identity in the PPIX molecules affected the bioactivity of the porphyrin. Importantly, the irradiation of the porphyrins did not enhance their potency in destroying Nosema spores. We showed that the porphyrins accumulated inside the living spores but not inside dead spores, thus the destruction of the microsporidia by non-metallated porphyrins is not dependent on photosensitization, but is associated with their active transport into the spore cell. When administered to honeybees in vivo, PPIX[Lys-TFA]₂ and PPIX[Lys-Lys]₂ reduced spore loads by 69–76% in infected individuals. They both had no toxic effect on honeybees, in contrast to zinc-coordinated porphyrin.

Molecular identification of Babesia spp isolated from Polish cattle with asymptomatic protozoa infections

The aim of the paper was to study the epizootic situation of babesiosis in the cattle population in eastern Poland and possibly to determine what species of protozoa infects Polish cattle. Blood samples for molecular analysis (real time PCR) were collected from 192 dairy cows from various farms located in eastern Poland. The infection was detected in 10.4% of the samples. All animals were infected with Babesia occultans which sequence of the 18S RNA gene fragment showed a 93.1%, homology with the sequence of B. occultans EU 376017. This is the first report about the detection of B. occultans DNA in asymptomatic cattle in eastern Poland.

Porphyrins inactivate Nosema spp. microsporidia

The study of organic/inorganic molecules with activity against intracellular fungi of the phylum Microsporidia is of critical importance. Here, for the first time, the inactivation of these parasitic fungi by porphyrins is reported. The biological effects of porphyrins (10 µM and 100 µM) on the microsporidian Nosema ceranae was investigated in honeybee hosts using cage experiments. A significant reduction in the number of spores (from 2.6 to 5 fold) was observed in Nosema-infected honeybees with a sucrose-protoporphyrin amide [PP(Asp)₂] syrup diet compared to the control honeybees. PP(Asp)₂ and the other porphyrin examined in vitro, TMePyP, had a direct impact on the microsporidia. Notably, neither porphyrin requires light excitation to be active against microsporidia. Moreover, microsporidia preincubated with these porphyrins exhibited decreased ability to infect honeybees. In particular, PP(Asp)₂, possessing amphiphilic characteristics, exhibited significant inactivation of microsporidia, preventing the development of the microsporidia and diminishing the mortality of infected honeybees. In addition, the porphyrin-treated spores examined by scanning electron microscopy (SEM) showed morphological changes in their exosporium layers, which were distinctly deformed. Thus, we postulate that the mechanism of action of porphyrins on microsporidia is not based on photodynamic inactivation but on the destruction of the cell walls of the spores.

Cardiac disorders in dogs infected with Babesia canis

The aim of this study was to assess cardiac disorders in dogs infected with B. canis. The study included 50 dogs with babesiosis and 20 healthy control animals. All the animals had haematological tests, ECG, echocardiography and serum troponin I and CK-MB levels checked. The haematology in the group of dogs with babesiosis confirmed thrombocytopaenia in 100% of dogs, decreased haematocrit in 52% and anaemia in 46%. The most common abnormalities in ECG and echocardiography in dogs infected with protozoa included: change in appearance and/or amplitude of the T-wave (34%), increased fractional shortening (24%), an increased sinus rhythm (14%) and heart axis deviation (10%). In 19 of the 50 dogs with babesiosis, the level of serum troponin I was elevated. In 2 dogs that died from babesiosis, the troponin level I was very high. The ECG confirmed sinus tachycardia and interpolated ventricular beat in these animals. In all dogs with babesiosis that were used in the study, the serum CK-MB was high or very high and was within limits of 23.17 U/L - 369.62 U/L. The highest kinase concentration (367.33 U/L and 369.62 U/L) was observed in dogs that died due to the disease. The presented results prove that cardiac changes are common in canine babesiosis, but that most changes are nonspecific and appear to have little clinical significance. Cardiovascular assessment should be based on the assessment of the level of troponin I and CK-MB in the serum of sick animals. High concentrations of these factors might be indicators of poor prognosis.

[Gastroenterological manifestations of von Hippel-Lindau disease - a case report]

Gastrointestinal organs are involved in the course of von Hippel Lindau disease. Typically pancreas in von Hippel Lindau syndrome is a site of cystic and solid tumors. Differential diagnosis of pancreatic lesions includes benign lesions (cysts, serous cystic adenomas), potentially malignant (neuroendocrine) and malignant tumors(metastases).In this work we present a patient with VHL syndrome with pancreatic cysts and neuroendocrine tumor.

[Gastroenterological manifestations of von Hippel-Lindau disease]

Von Hippel-Lindau disease is rare autosomal dominant disorder that results from mutation of VHL gene. Typical manifestations of this syndrome include haemangioblastomas of retina, cerebellum and spinal cord, endolymphatic sac tumors, clear cell cancer and kidney cysts, pheochromocytoma, pancreatic cysts and neuroendocrine tumors. The differential diagnosis of pancreatic lesions in patients with von Hippel Lindau syndrome plays an important role. The pancreas in VHL disease is not only site of benign lesions (cysts, serous systic adenomas) but also of potentially malignant (neuroendocrine) and malignant tumors(metastases).The gastroenterological manifestations can be the first symptoms of von Hippel-Lindau disease.