Can the size of the epiphysis determine the number of secondary ossification centers? A mathematical approach

Previous studies have concluded that the chemical feedback (loop) between two reagent molecular factors through a reaction-diffusion mechanism could explain the stable spatial pattern found in the origin of the secondary ossification centres (SOCs). Furthermore, the emergence of the SOC may depend on the size and shape of the head of the bone, as observed in different animals. In this paper, we develop new computer simulations that study the effect of the size of the epiphysis on the emergence of the SOC. This study determines two or more SOCs, that may appear in the head of long bones, depending on the size of the epiphysis.     

Ascorbate peroxidase 1 plays a key role in the response of Arabidopsis thaliana to stress combination

Within their natural habitat plants are subjected to a combination of different abiotic stresses, each with the potential to exacerbate the damage caused by the others. One of the most devastating stress combinations for crop productivity, which frequently occurs in the field, is drought and heat stress. In this study we conducted proteomic and metabolic analysis of Arabidopsis thaliana plants subjected to a combination of drought and heat stress. We identified 45 different proteins that specifically accumulated in Arabidopsis in response to the stress combination. These included enzymes involved in reactive oxygen detoxification, malate metabolism, and the Calvin cycle. The accumulation of malic enzyme during the combined stress corresponded with enhanced malic enzyme activity, a decrease in malic acid, and lower amounts of oxaloacetate, suggesting that malate metabolism plays an important role in the response of Arabidopsis to the stress combination. Cytosolic ascorbate peroxidase 1 (APX1) protein and mRNA accumulated during the stress combination. When exposed to heat stress combined with drought, an APX1-deficient mutant (apx1) accumulated more hydrogen peroxide and was significantly more sensitive to the stress combination than wild type. In contrast, mutants deficient in thylakoid or stromal/mitochondrial APXs were not more sensitive to the stress combination than apx1 or wild type. Our findings suggest that cytosolic APX1 plays a key role in the acclimation of plants to a combination of drought and heat stress.     

Antibiotic-producing Micrococcales govern the microbiome that inhabits the fur of two- and three-toed sloths

Sloths have a dense coat on which insects, algae and fungi coexist in a symbiotic relationship. This complex ecosystem requires different levels of controls; however, most of these mechanisms remain unknown. We investigated the bacterial communities inhabiting the hair of two- (Choloepus Hoffmanni) and three-toed (Bradypus variegatus) sloths and evaluated their potential for producing antibiotic molecules capable of exerting control over the hair microbiota. The analysis of 16S rRNA amplicon sequence variants revealed that the communities in both host species are dominated by Actinobacteriota and Firmicutes. The most abundant genera were Brevibacterium, Kocuria/Rothia, Staphylococcus, Rubrobacter, Nesterenkonia and Janibacter. Furthermore, we isolated nine strains of Brevibacterium and Rothia capable of producing substances that inhibited the growth of common mammalian pathogens. The analysis of the biosynthetic gene clusters of these nine isolates suggests that the pathogen-inhibitory activity could be mediated by the presence of siderophores, terpenes, beta-lactones, Type III polyketide synthases, ribosomally synthesized and post-translationally modified peptides, non-alpha poly-amino acids like e-Polylysine, ectoine or non-ribosomal peptides. Our data suggest that Micrococcales that inhabit sloth hair could have a role in controlling microbial populations in that habitat, improving our understanding of this highly complex ecosystem.     

Pollen dispersal in a population of Passiflora caerulea: spatial components and ecological implications

Plant Ecology - Sexual reproduction in Angiosperms mostly depends on pollen transfer mediated by an agent. In plants pollinated by biotic agents, reproductive success and population structure are...     

Polymorphisms in the TOLLIP Gene Influence Susceptibility to Cutaneous Leishmaniasis Caused by Leishmania guyanensis in the Amazonas State of Brazil

IntroductionThe clinical outcome to Leishmania-infection is determined by the individual adaptive immune T helper cell responses and their interactions with parasitized host cells. An early development of a proinflammatory immune response (Th1 response) is necessary for Leishmania-infection resolution. The Toll-interacting protein (TOLLIP) regulates human Toll-like receptors signaling pathways by down regulating the proinflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) and inducing the ant-inflammatory cytokine interleukin-10 (IL-10). Polymorphisms in the TOLLIP gene are associated with infectious diseases.ResultsThe G and T alleles of the rs5743899 and rs3750920 were more common in patients with CL than in healthy individuals (P = 2.6 x10^-8 ; odds ratio [OR], 1.7 [ 95% confidence interval (CI) 1.4–2.0] and P = 1.9 x10^-8 ; OR, 1.6 [95% CI 1.4–1.9] respectively). The r² and D’ linkage disequilibrium between the two polymorphisms are 0.05 and 0.473 with a confidence bounds of 0.37 to 0.57 respectively.ConclusionThe two polymorphisms are independently associated with an increased risk of developing CL.     

Urine protein profile of IgA nephropathy patients may predict the response to ACE-inhibitor therapy

This study was aimed at the search of urinary biomarkers which might help to predict the clinical response of IgA nephropathy (IgAN) patients to angiotensin converting enzyme inhibitors (ACEi). First, we studied the urinary proteome of 18 IgAN patients (toward 20 healthy controls) who had been chronically treated with ACEi by using 2-D PAGE coupled to nano-HPLC-ESI-MS/MS analysis. We identified 3 proteins, kininogen (p = 0.02), inter-alpha-trypsin-inhibitor heavy chain 4 (35 kDa fragment) (p = 0.02) and transthyretin (p<0.0001), whose urinary excretion was different in IgAN patients' responders when compared to those who had not responded to ACEi. A reduction of daily proteinuria >50% and a stable renal function over time were used to classify patients as responders. Then, we adopted immunoblotting to confirm the predictive power of one of the above proteins, kininogen, in 20 patients with biopsy-proven IgAN, before starting any therapy. Thus, we confirmed that very low levels of kininogen urine excretion were indeed predictive of an inadequate or absent clinical response to ACEi therapy of IgAN patients, after 6-month follow-up. Concluding, the analysis of urine proteome of IgAN patients generated a set of proteins which distinguished subjects responsive to ACEi from those unresponsive to the inhibition of renin-angiotensin system (RAS).     

Comparative genome sequence analysis underscores mycoparasitism as the ancestral life style of Trichoderma

Background

Mycoparasitism, a lifestyle where one fungus is parasitic on another fungus, has special relevance when the prey is a plant pathogen, providing a strategy for biological control of pests for plant protection. Probably, the most studied biocontrol agents are species of the genus Hypocrea/Trichoderma.

Results

Here we report an analysis of the genome sequences of the two biocontrol species Trichoderma atroviride (teleomorph Hypocrea atroviridis) and Trichoderma virens (formerly Gliocladium virens, teleomorph Hypocrea virens), and a comparison with Trichoderma reesei (teleomorph Hypocrea jecorina). These three Trichoderma species display a remarkable conservation of gene order (78 to 96%), and a lack of active mobile elements probably due to repeat-induced point mutation. Several gene families are expanded in the two mycoparasitic species relative to T. reesei or other ascomycetes, and are overrepresented in non-syntenic genome regions. A phylogenetic analysis shows that T. reesei and T. virens are derived relative to T. atroviride. The mycoparasitism-specific genes thus arose in a common Trichoderma ancestor but were subsequently lost in T. reesei.

Conclusions

The data offer a better understanding of mycoparasitism, and thus enforce the development of improved biocontrol strains for efficient and environmentally friendly protection of plants.     

Sperm quality and morphometry characterization of cryopreserved canine sperm in ACP-106c or TRIS

Morphological sperm evaluation supported by the morphometry can be used in the determination of the seminal quality and in the investigation of potential extenders. Although there are studies comparing TRIS and ACP extenders, there are no comparative studies between them for the computerized assisted semen analysis (CASA), sperm viability, membrane functionality and sperm morphometry parameters of cryopreserved canine semen. Hence, we aimed to evaluate the effects of ACP-106c and TRIS on post-freezing canine sperm quality. Five dogs were submitted to semen collection twice with one-week interval. The semen was evaluated within the parameters: total motility, vigor, concentration, viability, plasma membrane functionality, morphology and morphometry. In the morphometric evaluation, the morphologically normal sperm was measured as: length, width, area and perimeter of the head and the midpiece, tail length and total length. The parameters of ellipticity, elongation, regularity and roughness were determined. Then, the semen was divided into two aliquots that were diluted in TRIS or ACP-106c, with the addition of egg yolk and glycerol. The diluted semen was refrigerated and frozen. The thawed samples were evaluated. Total motility, viability, sperm membrane functionality and normal morphology reduced after thawing in both extenders (morphology reduced from 89.60 ± 1.3% to 84.40 ± 1.8 and 84.60 ± 1.1% in TRIS and ACP-106c, respectively). However, it did not differ between TRIS and ACP-106c. In the ACP-106c the sperm head defects in cryopreserved semen were higher compared to fresh semen (P < 0.05). For all the morphometric parameters evaluated, there were no differences between fresh and cryopreserved samples (3.70 ± 0.4% vs. 2.30 ± 0.5%). In kinetics, with an interval of one week statistical differences between the extenders were found only in the parameters ALH and LIN (P < 0.05). Regardless of the extender, there were no changes in the morphometric parameters of sperm after thawing.