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81.
The opportunity to study the effects of a powerful hurricane on monkey populations, diet, and behavior via pre- and post-hurricane data was presented when hurricane Iris virtually destroyed the forest along Monkey River in southern Belize on October 8, 2001, including a 52-ha area where black howlers have been subjects since 1999. Before the hurricane, 8 social groups, averaging 6.37 members, had been stable in both group composition and range for q 2 years. The hurricane, which levelled much of the forest, resulted in the complete loss of the forest canopy. The trees that remained standing lost most or all branches and were 100% defoliated. The monkey population in the study area was reduced by 42% and survivers experienced a period of extended social disorganization involving transient individuals, high numbers of solitary monkeys, and small fragmentary social groups. The period of disorganization lasted 12 weeks, after which the number of solitaries reduced and stability of the large groups increased. Within the study area, 5 social groups have been more or less stable since ca. week 15; however, home ranges had yet to stabilize at week 35. The social and ranging effects are similar to what has been described for translocated primates. Post-hurricane diet was limited to fruit and leaves remaining in the deadfall for the first 2 weeks and to new leaves and leaf buds for many weeks after that. Normal fruit consumption in April and May was prevented by the failure of surviving trees to produce fruit. With the loss of forest canopy there has been increased use of low foliage and ground travel, and with the reduction in population density there has been a reduction in vocalization frequency.  相似文献   
82.
A relatively novel biocide, ortho-phthalaldehyde (OPA), was tested to control biofilms formed by Pseudomonas fluorescens on stainless steel surfaces. The toxic action of OPA was assessed in terms of inactivation and removal of the biofilm by means of, respectively, the determination of the respiratory activity and the variation in the dry weight of the biofilms. For comparison, the activity of OPA against suspended bacteria was also evaluated. The results showed that higher concentrations of OPA and longer exposure times are needed to inactivate P. fluorescens biofilms than planktonic populations, thus denoting that sessile bacteria have a reduced susceptibility to OPA. This appears to be associated with the reaction with the proteins of the matrix, as demonstrated by the reduction of the antimicrobial action of OPA in the presence of a protein (bovine serum albumin). The application of OPA appeared to cause little effect in the removal of biofilms from the metal slides since the mass of biofilm that remained on the surfaces, after biocide treatment, was within the same range as those observed in the control tests. These results suggest that, with OPA application, biofilms can be inactivated but stay attached to the surfaces, decreasing thereby the success of the chemical treatment.  相似文献   
83.
The intracellular pathogen, Salmonella enterica, translocates type III effectors across its vacuolar membrane into host cells. Herein we describe a new Salmonella effector, PipB2, which has sequence similarity to another type III effector, PipB. In phagocytic cells, PipB2 localizes to the Salmonella-containing vacuole (SCV) and tubular extensions from the SCV, Salmonella-induced filaments (Sifs). We used the specific targeting of PipB2 in macrophages to characterize Sifs in phagocytic cells for the first time. In epithelial cells, PipB2 has a unique localization pattern, localizing to SCVs and Sifs and additionally to vesicles at the periphery of infected cells. We further show that the N-terminal 225-amino-acid residues of PipB2 are sufficient for type III translocation and association with SCVs and Sifs, but not peripheral vesicles. Subcellular fractionation demonstrated that both PipB and PipB2 associate with host cell membranes and resist extraction by high salt, high pH and to a significant extent, non-ionic detergent. Furthermore, PipB and PipB2 are enriched in detergent-resistant microdomains (DRMs), also known as lipid rafts, present on membranes of SCVs and Sifs. The enrichment of Salmonella effectors in DRMs on these intracellular membranes probably permits specific interactions with host cell molecules that are concentrated in these signalling platforms.  相似文献   
84.
Fusion and hypoplasia of the first two branchial arches, a defect typically observed in retinoic acid (RA) embryopathy, is generated in cultured mouse embryos upon treatment with BMS453, a synthetic compound that exhibits retinoic acid receptor beta (RARbeta) agonistic properties in transfected cells. By contrast, no branchial arch defects are observed following treatment with synthetic retinoids that exhibit RARalpha or RARgamma agonistic properties. The BMS453-induced branchial arch defects are mediated through RAR activation, as they are similar to those generated by a selective pan-RAR agonist, are prevented by a selective pan-RAR antagonist and cannot be mimicked by exposure to a pan-RXR agonist alone. They are enhanced in the presence of a pan-RXR agonist, and cannot be generated in Rarb-null embryos. Furthermore, they are accompanied, in the morphologically altered region, by ectopic expression of Rarb and of several other direct RA target genes. Therefore, craniofacial abnormalities characteristic of the RA embryopathy are mediated through ectopic activation of RARbeta/RXR heterodimers, in which the ligand-dependent activity of RXR is subordinated to that of RARbeta. Endodermal cells lining the first two branchial arches respond to treatment with the RARbeta agonist, in contrast to neural crest cells and ectoderm, which suggests that a faulty endodermal regionalization is directly responsible for RA-induced branchial arch dysmorphologies. Additionally, we provide the first in vivo evidence that the synthetic RARbeta agonist BMS453 exhibits an antagonistic activity on the two other RAR isotypes.  相似文献   
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86.
This work presents the results of a demographic analysis of 30 years of breeding records from the University of Washington's recently closed Primate Field Station at Medical Lake, Washington. Summaries of population growth, age-specific fertility and mortality rates, first-year survival, and seasonality of reproduction are presented, as well as an analysis of survival by decade. In addition, we present data on interbirth intervals in this population. In general, pigtailed macaques represent a typical Old World monkey pattern of age-specific fertility and mortality, with a few minor exceptions. We suggest that pigtailed macaques are most similar to rhesus and Barbary macaques, and that Japanese and bonnet macaques differ somewhat in their demographics.  相似文献   
87.
Lacticin 3147 is a broad-spectrum bacteriocin produced by Lactococcus lactis subsp. lactis DPC3147 (M. P. Ryan, M. C. Rea, C. Hill, and R. P. Ross, Appl. Environ. Microbiol. 62:612–619, 1996). Partial purification of the bacteriocin by hydrophobic interaction chromatography and reverse-phase fast protein liquid chromatography revealed that two components are required for full activity. Lacticin 3147 is bactericidal against L. lactis, Listeria monocytogenes, and Bacillus subtilis; at low concentrations of the bacteriocin, bactericidal activity is enhanced when target cells are energized. This finding suggests that the presence of a proton motive force promotes the interaction of the bacteriocin with the cytoplasmic membrane, leading to the formation of pores at these low lacticin 3147 concentrations. These pores were shown to be selective for K+ ions and inorganic phosphate. The loss of these ions resulted in immediate dissipation of the membrane potential and hydrolysis of internal ATP, leading to an eventual collapse of the pH gradient at the membrane and ultimately to cell death. Our results suggest that lacticin 3147 is a pore-forming bacteriocin which acts on a broad range of gram-positive bacteria.  相似文献   
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90.
Amebiasis is an endemic disease and a public health problem throughout Mexico, although the incidence rates of amebic liver abscess (ALA) vary among the geographic regions of the country. Notably, incidence rates are high in the northwestern states (especially Sonora with a rate of 12.57/100,000 inhabitants) compared with the central region (Mexico City with a rate of 0.69/100,000 inhabitants). These data may be related to host genetic factors that are partially responsible for resistance or susceptibility. Therefore, we studied the association of the HLA-DRB1 and HLA-DQB1 alleles with resistance or susceptibility to ALA in two Mexican populations, one each from Mexico City and Sonora. Ninety ALA patients were clinically diagnosed by serology and sonography. Genomic DNA was extracted from peripheral blood mononuclear cells. To establish the genetic identity of both populations, 15 short tandem repeats (STRs) were analyzed with multiplexed PCR, and the allelic frequencies of HLA were studied by PCR-SSO using LUMINEX technology. The allele frequencies obtained were compared to an ethnically matched healthy control group (146 individuals). We observed that both affected populations differed genetically from the control group. We also found interesting trends in the population from Mexico City. HLA-DQB1*02 allele frequencies were higher in ALA patients compared to the control group (0.127 vs 0.047; p= 0.01; pc= NS; OR= 2.9, 95% CI= 1.09-8.3). The less frequent alleles in ALA patients were HLA-DRB1*08 (0.118 vs 0.238 in controls; p= 0.01; pc= NS; OR= 0.42, 95% CI= 0.19-0.87) and HLA-DQB1*04 (0.109 vs 0.214; p= 0.02; pc= NS; OR= 0.40, 95% CI= 0.20-0.94). The haplotype HLA-DRB1*08/-DQB1*04 also demonstrated a protective trend against the development of this disease (0.081 vs. 0.178; p=0.02; pc=NS; OR= 0.40, 95% CI= 0.16-0.93). These trends suggest that the prevalent alleles in the population of Mexico City may be associated with protection against the development of ALA.  相似文献   
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