Mitochondrial anti-viral immunity

In the cytosol, the sensing of RNA viruses by the RIG-I-like receptors (RLRs) triggers a complex signaling cascade where the mitochondrial antiviral signaling protein (MAVS) plays a crucial role in orchestrating the innate host response through the induction of antiviral and inflammatory responses. Hence, in addition to their known roles in the metabolic processes and the control of programmed cell death, mitochondria are now emerging as a fundamental hub for innate anti-viral immunity. This review summarizes the findings related to the MAVS adapter and mitochondria in the innate immune response to RNA viruses.     

Causes and predictors of nest mortality in a European rabbit population

We conducted a study on nest mortality of an individually marked population of European rabbits (Oryctolagus cuniculus L., 1758) living in a field enclosure. Over 4 years, we determined maternities and quantified pup mortality during the nest period of 703 pups born in subterranean breeding burrows. Overall, pup mortality occurred in 42.7% of the litters, whereas 32.4% of all born pups were affected. Mortality was highest during the first few postnatal days. In about 50% of the cases, we managed to quantify different causes of mortality such as malnutrition, flooding, cooling of the pups, infanticide, or predation. The pups’ body mass on postnatal day 1, the thermal environment and the number of litter mates were the most important predictors of nest mortality. Litter mortality risk decreased with increasing soil temperature around the subterranean nests. A comparatively higher average pup body mass lowered the nest mortality risk of a litter, whereas this effect was more pronounced when soil temperatures were low. Furthermore, mortality was lowest in medium-sized litters, most probably due to the balance between the thermal benefits of huddling with litter siblings and the costs of having them due to the lower share of milk obtained by the individual pups in larger litters. In addition, nest mortality depended on characteristics of the mother; mortality was increased in litters of low-ranking females and of mothers with lower body mass. In conclusion, our study highlights multiple causes and the effects of different environmental and social factors on nest mortality of this small mammal.     

Purification of human galectin-1 produced in high-cell density cultures of recombinant Escherichia coli: a comparison with classic shake flask cultivation

The aim of the present work was to develop a highly productive and simplified process for active human galectin-1 (Gal1) production. Gal1 is a beta-galactoside binding lectin that differentially affects biological and cellular functions such as immune surveillance and apoptosis. These effects have attracted the attention of researchers in cell biology, biochemistry and immunology. However, the production of sufficient amounts of recombinant human Gal1 (rhGal1) is needed to study of the effects of Gal1 during cell treatments. To this end, an high-yield expression of rhGal1 was achieved by high-cell density fed-batch cultivation using an exponential glycerol feeding strategy and rhGal1 was purified by a one-step purification scheme using affinity chromatography.     

New antibacterial peptide derived from bovine hemoglobin

Peptic digestion of bovine hemoglobin at low degree of hydrolysis yields an intermediate peptide fraction exhibiting antibacterial activity against Micrococcus luteus A270, Listeria innocua, Escherichia coli and Salmonella enteritidis after separation by reversed-phase HPLC. From this fraction a pure peptide was isolated and analyzed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and electrospray ionization tandem mass spectrometry (ESI-MS/MS). This peptide correspond to the 107-136 fragment of the alpha chain of bovine hemoglobin. The minimum inhibitory concentrations (MIC) towards the four strains and its hemolytic activity towards bovine erythrocytes were determined. A MIC of 38 microM was reported against L. innocua and 76 microM for other various bacterial species. This peptide had no hemolytic activity up to 380 microM concentration.     

Synthesis of <Emphasis Type="Italic">scl</Emphasis>-poly (3-hydroxyalkanoates) by <Emphasis Type="Italic">Bacillus cereus</Emphasis> found in freshwater,from monosaccharides and disaccharides

Background

Polyhydroxyalkanoates are a good substitute for synthetic plastic because they are highly biocompatible, ecofriendly, and biodegradable. Bacteria in freshwater bodies such as rivers, tube wells, and canals are exposed to alternating high and low concentrations of substrates that induce PHA production.

Methods

Fresh water samples were collected for isolation of bacterial strains. Screening of PHA in bacterial cells was performed with Sudan and Nile Red staining. Extracted PHA was characterized by FTIR.

Results

In this study, nine bacterial isolates were selected for PHA production on the basis of phenotypic screening. Their ability to accumulate PHAs was determined using different monosaccharides and disaccharides. Two bacterial isolates Bacillus cereus T1 (KY746353) and Bacillus cereus R3 (KY746354) produced PHAs. Optimal growth of the bacterial strain (T1) was observed in the presence of glucose, followed by maximum production of PHAs (63% PHAs) during the logarithmic phase of growth. B. cereus R3 (KY746354) accumulated 60% PHAs by dry cell weight.

Conclusion

PHA accumulation was relatively less with fructose, but both strains showed increased production (up to 50%) with sucrose. The polymer produced was characterized by Fourier-transform infrared spectroscopy (FTIR), which showed that the compound contains short-chain PHAs.

     

At least five polymorphic mutants account for the prevalence of glucose-6-phosphate dehydrogenase deficiency in Algeria

The electrophoretic mobility and level of enzyme activity of glucose-6-phosphate dehydrogenase (G6PD) was established in 100 unrelated Algerian males with G6PD deficiency. DNA from these subjects was analysed for the presence of certain known G6PD mutations by the appropriate restriction enzyme digestion of fragments amplified by the polymerase chain reaction. Where the mutation could not be identified in this way, the samples were subjected to single-strand conformation polymorphism analysis and abnormal fragments were sequenced. In this way, eight different mutations have been identified, of which five are polymorphic and account for 92% of the samples. The most common variants are G6PD A-(46%) and G6PD Mediterranean (23%), both of which were associated with favism. A new polymorphic variant, G6PD Aures, has been identified during the course of this study, whereas another, G6PD Santamaria, has now been established as a polymorphic variant (11%). Thus, G6PD deficiency in Algeria is heterogeneous, suggesting that there has been significant gene flow, both from sub-Saharan Africa and from other parts of the Mediterranean.     

Identification and molecular docking of novel ACE inhibitory peptides from protein hydrolysates of shrimp waste

The effect of enzymatic hydrolysis by Savinase on the interfacial properties and antihypertensive activity of shrimp waste proteins was evaluated. The physicochemical characterization, interfacial tension, and surface characteristics of shrimp waste protein hydrolysates (SWPH) using different enzyme/substrate (E/S) (SWPH₅ (SWPH using E/S = 5), SWPH₁₅ (SWPH using E/S = 15), and SWPH₄₀ (SWPH using E/S = 40)) were also studied. SWPH₅, SWPH₁₅, and SWPH₄₀ had an isoelectric pH around 2.07, 2.17, and 2.54 respectively. SWPH₅ exhibited the lowest interfacial tension (68.96 mN/m) followed by SWPH₁₅ (69.36 mN/m) and SWPH₄₀ (70.29 mN/m). The in vitro ACE inhibitory activity of shrimp waste protein hydrolysates showed that the most active hydrolysate was obtained using an enzyme/substrate of 15 U/mg (SWPH₁₅). SWPH₁₅ had a lower IC₅₀ value (2.17 mg/mL) than that of SWPH₅ and SWPH₄₀ (3.65 and 5.7 mg/mL, respectively). This hydrolysate was then purified and characterized. Fraction F1 separated by Sephadex G25 column which presents the best ACE inhibition activity was then separated by reversed‐phase high performance liquid chromatography. Four ACE inhibitory peptides were identified and their molecular masses and amino acid sequences were determined using ESI–MS and ESI–MS/MS, respectively. The structures of the most potent peptides were SSSKAKKMP, HGEGGRSTHE, WLGHGGRPDHE, and WRMDIDGDIMISEQEAHQR. The structural modeling of anti‐ACE peptides from shrimp waste through docking simulations results showed that these peptides bound to ACE with high affinity.     

Current prophylactic and therapeutic uses of a recombinant Lactococcus lactis strain secreting biologically active interleukin-12

The noninvasive and food-grade Gram-positive bacterium Lactococcus lactis is well adapted to deliver medical proteins to the mucosal immune system. In the last decade, the potential of live recombinant lactococci to deliver such proteins to the mucosal immune system has been investigated. This approach offers several advantages over the traditional systemic injection, such as easy administration and the ability to elicit both systemic and mucosal immune responses. This paper reviews the current research and advances made with recombinant L. lactis as live vector for the in situ delivery of biologically active interleukin-12, a potent pleiotropic cytokine with adjuvant properties when co-delivered with vaccinal antigens, at mucosal surfaces. Three well-illustrated examples demonstrate the high potential of interleukin-12-secreting lactococci strains for future prophylactic and therapeutic uses.     

First Report of Pythium indigoferae and P. irregulare Associated to Apple Trees Decline in Tunisia

Pythium indigoferae and Pythium irregulare, identified based on morphological and physiological characteristics, were isolated from necrotic roots, crown tissues and the rhizosphere of apple trees in Tunisia from 23 apple orchards in spring and autumn 2007–2009. The virulence assays on excised twigs, using different Pythium species isolated demonstrated that these oomycetes were pathogenic on the Anna, Lorka and Meski varieties and the MM106 rootstock. However, the biggest lesion area was noted on MM106 rootstock. Thus, it appeared that this rootstock is more susceptible to Pythium infections than Anna, Meski and Lorka apple varieties. Furthermore, it is important to note that in vitro tests showed that P. indigoferae seems to be more virulent than P. irregulare.