Thie expression of an intraspecific aggressive reaction in the face of a stressor agent alters the immune response in rats.

The repercussion on the immune response of the expression of intraspecific aggressiveness in the face of a stressor agent was investigated in rats. Ninety-day-old animals were divided into three groups: the control group (only immunological measurements were performed), the foot-shock (FS) (animals individually receiving FS), and the intraspecific aggressive response (IAR) group (animals receiving FS and presenting IAR). For immunological measurements, blood samples were collected promptly at 7 and 15 days after FS or IAR. The FS reduced the total leukocyte amount presented. However, aggressiveness triggered not only reduction of the leukocytes, but also lymphocyte decrease and neutrophil increase. Moreover, an elevation in total leukocytes associated with an increase in the humoral immune response was also observed one week after IAR. In this study, the expression of intraspecific aggressiveness in the face of a stressor seemed to activate the immune system and to potentiate the antigen specific humoral response.     

Self-Interaction of Human Pex11pβ during Peroxisomal Growth and Division

Pex11 proteins are involved in membrane elongation and division processes associated with the multiplication of peroxisomes. Human Pex11pβ has recently been linked to a new disorder affecting peroxisome morphology and dynamics. Here, we have analyzed the exact membrane topology of Pex11pβ. Studies with an epitope-specific antibody and protease protection assays show that Pex11pβ is an integral membrane protein with two transmembrane domains flanking an internal region exposed to the peroxisomal matrix and N- and C-termini facing the cytosol. A glycine-rich internal region within Pex11pβ is dispensable for peroxisome membrane elongation and division. However, we demonstrate that an amphipathic helix (Helix 2) within the first N-terminal 40 amino acids is crucial for membrane elongation and self-interaction of Pex11pβ. Interestingly, we find that Pex11pβ self-interaction strongly depends on the detergent used for solubilization. We also show that N-terminal cysteines are not essential for membrane elongation, and that putative N-terminal phosphorylation sites are dispensable for Pex11pβ function. We propose that self-interaction of Pex11pβ regulates its membrane deforming activity in conjunction with membrane lipids.     

Rho GTPases regulate PRK2/PKN2 to control entry into mitosis and exit from cytokinesis

Rho GTPases regulate multiple signal transduction pathways that influence many aspects of cell behaviour, including migration, morphology, polarity and cell cycle. Through their ability to control the assembly and organization of the actin and microtubule cytoskeletons, Rho and Cdc42 make several key contributions during the mitotic phase of the cell cycle, including spindle assembly, spindle positioning, cleavage furrow contraction and abscission. We now report that PRK2/PKN2, a Ser/Thr kinase and Rho/Rac effector protein, is an essential regulator of both entry into mitosis and exit from cytokinesis in HeLa S3 cells. PRK2 is required for abscission of the midbody at the end of the cell division cycle and for phosphorylation and activation of Cdc25B, the phosphatase required for activation of mitotic cyclin/Cdk1 complexes at the G2/M transition. This reveals an additional step in the mammalian cell cycle controlled by Rho GTPases.     

Purification and partial characterization of two phospholipases A2 from Bothrops leucurus (white-tailed-jararaca) snake venom

Two proteins with phospholipase A(2) (PLA(2)) activity were purified to homogeneity from Bothrops leucurus (white-tailed-jararaca) snake venom through three chromatographic steps: Conventional gel filtration on Sephacryl S-200, ion-exchange on Q-Sepharose and reverse phase on Vydac C4 HPLC column. The molecular mass for both enzymes was estimated to be approximately 14 kDa by SDS-PAGE. The N-terminal sequences (48 residues) show that one enzyme presents lysine at position 48 and the other an aspartic acid in this position, and therefore they were designated blK-PLA(2) and blD-PLA(2) respectively. blK-PLA(2) presented negligible levels of PLA(2) activity as compared to that of blD-PLA(2). The PLA(2) activity of both enzymes is Ca(2+)-dependent. blD-PLA(2) did not have any effect upon platelet aggregation induced by arachidonic acid, ADP or collagen, but strongly inhibits coagulation and is able to stimulate Ehrlich tumor growth but not angiogenesis.     

Genetic diversity for aluminum tolerance in sorghum

Genetic variation for aluminum (Al) tolerance in plants has allowed the development of cultivars that are high yielding on acidic, Al toxic soils. However, knowledge of intraspecific variation for Al tolerance control is needed in order to assess the potential for further Al tolerance improvement. Here we focused on the major sorghum Al tolerance gene, Alt _SB , from the highly Al tolerant standard SC283 to investigate the range of genetic diversity for Al tolerance control in sorghum accessions from diverse origins. Two tightly linked STS markers flanking Alt _SB were used to study the role of this locus in the segregation for Al tolerance in mapping populations derived from different sources of Al tolerance crossed with a common Al sensitive tester, BR012, as well as to isolate the allelic effects of Alt _SB in near-isogenic lines. The results indicated the existence not only of multiple alleles at the Alt _SB locus, which conditioned a wide range of tolerance levels, but also of novel sorghum Al tolerance genes. Transgressive segregation was observed in a highly Al tolerant breeding line, indicating that potential exists to exploit the additive or codominant effects of distinct Al tolerance loci. A global, SSR-based, genetic diversity analysis using a broader sorghum set revealed the presence of both multiple Alt _SB alleles and different Al tolerance genes within highly related accessions. This suggests that efforts toward broadening the genetic basis for Al tolerance in sorghum may benefit from a detailed analysis of Al tolerance gene diversity within subgroups across a target population. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Prevalence and diversity of gastrointestinal parasites in free-ranging rhesus macaques (Macaca mulatta) in different land gradients of Bangladesh

Rhesus macaques are considered an important reservoir of different gastrointestinal (GI) zoonotic parasites affecting livestock and humans. Loads of GI parasites in the free-ranging rhesus macaques living in close proximity to communities in Bangladesh are still unknown. To estimate the prevalence and diversity of zoonotic GI parasites in rhesus macaques of Bangladesh, a total of 182 freshly voided fecal samples were collected from macaques living in rural (N = 67), peri-urban (N = 57), urban (N = 28), and Safari park (N = 30) between October 2015 and December 2016. All samples were tested by direct smear, sedimentation, flotation, and the McMaster techniques. A total of fourteen different taxa of GI parasites were detected, revealing an overall prevalence of 54.4% (n = 99; 95% confidence interval [CI]: 46.9–61.8). The prevalence of GI parasites was found to be significantly correlated with the mean parasitic taxa per individual in a group (r = 0.90; p = 0.002). The multivariable logistic regression analysis showed that the overall prevalence of GI parasites in macaques was significantly higher in those inhabiting rural areas (62.69%; odds ratio [OR]: 7.22; p = 0.001) and in macaques with interactions with other animals (60.98%; OR: 5.49; p = 0.005). Our results also indicated that the prevalence of Strongyloides spp. and Balantidium coli infections varied significantly between land gradients. Our results also indicate that macaques frequently visit human settlements for food and are found interacting with domestic animals. In conclusion, the high prevalence of zoonotic GI parasite infection in rhesus macaques found in our study may pose a significant public health risk to communities, particularly in rural areas of Bangladesh. Health promotion to at-risk communities focusing on limiting contact with rhesus macaques is necessary to mitigate potential zoonotic transmission.     

Diet of intraguild predators affects antipredator behavior in intraguild prey

In two-predator, one-prey systems with intraguild predationand patchily distributed prey, the intraguild prey may facea choice between prey patches with and without intraguild predators.To minimize falling victim to intraguild predation, intraguildprey are expected to perceive cues specifically associated withthe presence of intraguild predators. We investigate whetherintraguild prey avoided intraguild predators and which cuestriggered this behavior in a system composed of plant-inhabitingarthropods. We found that intraguild prey recognized intraguildpredators from a distance, based on their diet: they avoidedodors of intraguild predators that had consumed shared preybut did not avoid odors of intraguild predators that had fedon other diets, including a diet of conspecifics. When intraguildprey were foraging on a patch, detection of intraguild predatorsled to longer periods of immobility and to fewer captures ofthe shared prey. However, intraguild predators that were eitherstarved or had previously consumed intraguild prey posed a higherrisk to intraguild prey than did intraguild predators that hadconsumed the shared prey. We conclude that the cues used byintraguild prey to avoid intraguild predators are associatedwith the circumstances under which they encounter intraguildpredators in the field and not to different degrees of danger.