Biological activity of Bacillus thuringiensis strains against larvae of the blowfly Chrysomya putoria (Wiedemann) (Diptera: Calliphoridae)

Different strains of Bacillus thuringiensis Berliner were proved to be a powerful biologic insecticide against larvae of several insect orders. Due to the epidemiological importance of blowflies of the Chrysomya Robineau-Desvoidy genus in the production of secondary cutaneous myiasis and mechanic transmission of pathogenic agents, the performance of two strains of B. thuringiensis (LFB-FIOCRUZ 907 and LFB-FIOCRUZ 856) was tested against larvae of Chrysomya putoria (Wiedemann). The LFB-FIOCRUZ 907 strain was tested in four different concentrations, added to the diet; the LFB-FIOCRUZ 856 strain was tested in three concentrations. C. putoria larvae showed sensibility to the treatment with the LFB-FIOCRUZ 907 strain at the tested concentrations. The higher concentration presented the best efficiency, causing higher mortality and reducing larval weight and adult emergence more intensely. The LFB-FIOCRUZ 856 strain showed low toxicity, slightly reducing emergence time of adults at 326 mg/25 g concentration and larval weight at 326 mg/25 g and 86 mg/25 g concentrations.     

Adiponectin multimers and metabolic syndrome traits: relative adiponectin resistance in African Americans

African Americans (AAs) tend to have lower total adiponectin levels compared to European Americans (EA); however, it is not known whether race affects adiponectin multimer distribution and their relationships to metabolic traits. We measured total adiponectin, high molecular weight (HMW), low molecular weight (LMW) (i.e., hexamer), and trimer adiponectin in 132 normoglycemic premenopausal women (75 AAs, 57 EAs), together with measures of total and abdominal fat, plasma lipids, insulin sensitivity (S(i)), and genetic admixture estimates. We found that lower total adiponectin in AAs was explained by reduced LMW, and trimer forms because levels of HMW did not differ between races. In EAs, HMW was highly correlated with multiple metabolic syndrome traits. In contrast, the LMW and trimer forms were most highly correlated with metabolic traits in AAs, including abdominal adiposity, lipids, and S(i). At similar levels of visceral adiposity, AAs exhibited significantly lower LMW adiponectin than EAs. Similarly, at comparable levels of HMW and LMW adiponectin, AAs were more insulin resistant than their EA counterparts. In conclusion, (i) serum adiponectin is lower in AAs predominantly as a result of reduced concentrations of LMW and trimers multimeric forms; (ii) LMW and trimer, not HMW, are most broadly correlated with metabolic traits in AAs. Thus, HMW adiponectin may exert less bioactivity in explaining the metabolic syndrome trait cluster in populations of predominant African genetic background.     

OPT3 Is a Phloem-Specific Iron Transporter That Is Essential for Systemic Iron Signaling and Redistribution of Iron and Cadmium in Arabidopsis

Iron is essential for both plant growth and human health and nutrition. Knowledge of the signaling mechanisms that communicate iron demand from shoots to roots to regulate iron uptake as well as the transport systems mediating iron partitioning into edible plant tissues is critical for the development of crop biofortification strategies. Here, we report that OPT3, previously classified as an oligopeptide transporter, is a plasma membrane transporter capable of transporting transition ions in vitro. Studies in Arabidopsis thaliana show that OPT3 loads iron into the phloem, facilitates iron recirculation from the xylem to the phloem, and regulates both shoot-to-root iron signaling and iron redistribution from mature to developing tissues. We also uncovered an aspect of crosstalk between iron homeostasis and cadmium partitioning that is mediated by OPT3. Together, these discoveries provide promising avenues for targeted strategies directed at increasing iron while decreasing cadmium density in the edible portions of crops and improving agricultural productivity in iron deficient soils.     

Assembly of the sarcoplasmic reticulum. Cell-free synthesis of te Ca2+ + Mg2+-adenosine triphosphatase and calsequestrin

Polyadenylated RNA prepared from neonatal rat muscle was translated in a rabbit reticulocyte cell-free system. Two sarcoplasmic reticulum proteins, the Ca2+ + Mg2+-dependent adenosine triphosphatase (ATPase) and calsequestrin, were isolated from the translation mixture by immunoprecipitation, followed by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels. The [35S]methionine-labeled translation products were characterized by molecular weight, peptide mapping, and NH2-terminal sequence analysis. The ATPase synthesized in the cell-free system was found to have the same molecular weight (Mr = 100,000) and [35S]-methionine-labeled peptide map as the mature ATPase. The methionine residue present at the NH2 terminus of the mature ATPase was donated by initiator methionyl-tRNArMet and it became acetylated during translation. These results suggest that the ATPase was synthesized without an NH2-terminal signal sequence. Calsequestrin (Mr - 63,000) was synthesized as a higher molecular weight precursor (Mr = 66,000) that contained an additional [35S]methionine-labeled peptide when compared to mature calsequestrin. The NH2-terminal sequence of the precursor was different from the mature protein. The precursor was processed to a polypeptide with a molecular weight identical with mature calsequestrin when microsomal membranes prepared from canine pancreas were included during translation. These results show that calsequestrin is synthesized with an NH2-terminal signal sequence that is removed during translation. These data add to the evidence that the ATPase and calsequestrin follow distinctly different biosynthetic pathways, even though, ultimately, they are both located in the same membrane.     

Recent advances on applications and biotechnological production of d-psicose

D-Psicose is a hexoketose monosaccharide sweetener, which is a C-3 epimer of D-fructose and is rarely found in nature. It has 70 % relative sweetness but 0.3 % energy of sucrose, and is suggested as an ideal sucrose substitute for food products. It shows important physiological functions, such as blood glucose suppressive effect, reactive oxygen species scavenging activity, and neuroprotective effect. It also improves the gelling behavior and produces good flavor during food process. This article presents a review of recent studies on the properties, physiological functions, and food application of D-psicose. In addition, the biochemical properties of D-tagatose 3-epimerase family enzymes and the D-psicose-producing enzyme are compared, and the biotechnological production of D-psicose from D-fructose is reviewed.     

SARS-CoV-2 viral dynamics in non-human primates

Non-human primates infected with SARS-CoV-2 exhibit mild clinical signs. Here we used a mathematical model to characterize in detail the viral dynamics in 31 cynomolgus macaques for which nasopharyngeal and tracheal viral load were frequently assessed. We identified that infected cells had a large burst size (>10⁴ virus) and a within-host reproductive basic number of approximately 6 and 4 in nasopharyngeal and tracheal compartment, respectively. After peak viral load, infected cells were rapidly lost with a half-life of 9 hours, with no significant association between cytokine elevation and clearance, leading to a median time to viral clearance of 10 days, consistent with observations in mild human infections. Given these parameter estimates, we predict that a prophylactic treatment blocking 90% of viral production or viral infection could prevent viral growth. In conclusion, our results provide estimates of SARS-CoV-2 viral kinetic parameters in an experimental model of mild infection and they provide means to assess the efficacy of future antiviral treatments.     

Ciprofloxacin-Eluting Nanofibers Inhibits Biofilm Formation by Pseudomonas aeruginosa and a Methicillin-Resistant Staphylococcus aureus

Pseudomonas aeruginosa and Staphylococcus aureus are commonly associated with hospital-acquired infections and are known to form biofilms. Ciprofloxacin (CIP), which is normally used to treat these infections, is seldom effective in killing cells in a biofilm. This is mostly due to slow or weak penetration of CIP to the core of biofilms. The problem is accentuated by the release of CIP below MIC (minimal inhibitory concentration) levels following a rapid (burst) release. The aim of this study was to develop a drug carrier that would keep CIP above MIC levels for an extended period. Ciprofloxacin was suspended into poly(D,L-lactide) (PDLLA) and poly(ethylene oxide) (PEO), and electrospun into nanofibers (CIP-F). All of the CIP was released from the nanofibers within 2 h, which is typical of a burst release. However, 99% of P. aeruginosa PA01 cells and 91% of S. aureus Xen 30 cells (a methicillin-resistant strain) in biofilms were killed when exposed to CIP-F. CIP levels remained above MIC for 5 days, as shown by growth inhibition of the cells in vitro. The nanofibers were smooth in texture with no bead formation, as revealed by scanning electron and atomic force microscopy. A single vibration peak at 1632 cm^-1, recorded with Fourier transform infrared spectroscopy, indicated that CIP remained in crystal form when incorporated into PDLLA: PEO. No abnormalities in the histology of MCF-12A breast epithelial cells were observed when exposed to CIP-F. This is the first report of the inhibition of biofilm formation by CIP released from PDLLA: PEO nanofibers.