Influence of climatic variables, forest type, and condition on activity patterns of Geoffroyi's spider monkeys throughout Mesoamerica

Understanding how species cope with variations in climatic conditions, forest types and habitat amount is a fundamental challenge for ecologists and conservation biologists. We used data from 18 communities of Mesoamerican spider monkeys (Ateles geoffroyi) throughout their range to determine whether their activity patterns are affected by climatic variables (temperature and rainfall), forest types (seasonal and nonseasonal forests), and forest condition (continuous and fragmented). Data were derived from 15 published and unpublished studies carried out in four countries (Mexico, El Salvador, Costa Rica, and Panama), cumulatively representing more than 18 years (221 months, >3,645 hr) of behavioral observations. Overall, A. geoffroyi spent most of their time feeding (38.4 ± 14.0%, mean ± SD) and resting (36.6 ± 12.8%) and less time traveling (19.8 ± 11.3%). Resting and feeding were mainly affected by rainfall: resting time increased with decreasing rainfall, whereas feeding time increased with rainfall. Traveling time was negatively related to both rainfall and maximum temperature. In addition, both resting and traveling time were higher in seasonal forests (tropical dry forest and tropical moist forest) than in nonseasonal forests (tropical wet forest), but feeding time followed the opposite pattern. Furthermore, spider monkeys spent more time feeding and less time resting (i.e., higher feeding effort) in forest fragments than in continuous forest. These findings suggest that global climate changes and habitat deforestation and fragmentation in Mesoamerica will threaten the survival of spider monkeys and reduce the distributional range of the species in the coming decades. Am. J. Primatol. 73:1189–1198, 2011. © 2011 Wiley Periodicals, Inc.     

Extremely low-frequency magnetic fields can impair spermatogenesis recovery after reversible testicular damage induced by heat

Male infertility is often related to reproductive age couples experiencing fertility-related issues. Men may have fertility problems associated with reversible testicular damage. Considering that men have been increasingly exposed to extremely low-frequency magnetic fields generated by the production, distribution and use of electricity, this study analyzed whether 60?Hz and 1?mT magnetic field exposure may impair spermatogenesis recovery after reversible testicular damage induced by heat shock using rats as an experimental model. Adult male rats were subjected to a single testicular heat shock (HS, 43?°C for 12?min) and then exposed to the magnetic field for 15, 30 and 60?d after HS. Magnetic field exposure during the spermatogenesis recovery induced changes in testis components volume, cell ultrastructure and histomorphometrical parameters. Control animals had a reestablished and active spermatogenesis at 60?d after heat shock, while animals exposed to magnetic field still showed extensive testicular degeneration. Magnetic field exposure did not change the plasma testosterone. In conclusion, extremely low-frequency magnetic field may be harmful to fertility recovery in males affected by reversible testicular damage.     

The high level of aluminum resistance in signalgrass is not associated with known mechanisms of external aluminum detoxification in root apices

Al resistance of signalgrass (Brachiaria decumbens Stapf cv Basilisk), a widely sown tropical forage grass, is outstanding compared with the closely related ruzigrass (Brachiaria ruziziensis Germain and Evrard cv Common) and Al-resistant genotypes of graminaceous crops such as wheat, triticale, and maize. Secretion of organic acids and phosphate by root apices and alkalinization of the apical rhizosphere are commonly believed to be important mechanisms of Al resistance. However, root apices of signalgrass secreted only moderately larger quantities of organic acids than did those of ruzigrass, and efflux from signalgrass apices was three to 30 times smaller than from apices of Al-resistant genotypes of buckwheat, maize, and wheat (all much more sensitive to Al than signalgrass). In the presence, but not absence, of Al, root apices of signalgrass alkalinized the rhizosphere more than did those of ruzigrass. The latter was associated with a shortening of the alkalinizing zone in Al-intoxicated apices of ruzigrass, indicating that differences in alkalinizing power were a consequence, not a cause of, differential Al resistance. These data indicate that the main mechanism of Al resistance in signalgrass does not involve external detoxification of Al. Therefore, highly effective resistance mechanisms based on different physiological strategies appear to operate in this species.     

Effect of Echinacea purpurea (Asteraceae) aqueous extract on antibody response to Bothrops asper venom and immune cell response

The effect of aqueous extract of Echinacea purpurea roots on the murine antibody response to Bothrops asper snake venom in vivo was studied. Three groups were used. Group #1, baseline control, was treated with snake venom plus PBS. Group #2 was treated with snake venom plus sodium alginate as adjuvant (routine method used at Instituto Clodomiro Picado), and group #3 or experimental group, was treated with snake venom plus aqueous extract ofE. purpurea root as adjuvant. In all groups, the first inoculation was done with Freund's complete adjuvant (FCA). By the time of the second bleeding, mice in group #3 showed a remarkable increment in the level of anti-venom antibodies compared with those in groups #1 or #2. In vitro immune cell proliferation as a response to aqueous extract of E. purpurea root was studied using human lymphocytes activated with different lectins (Con A, PHA and PWM). In all cases, increase in percentage of lymphoproliferation was greater when E. purpurea root extract was used in addition to individual lectins.     

Hb Costa Rica or · 2 ‚ 277(EF1)His→Arg: the first example of a somatic cell mutation in a globin gene

We have identified a minor hemoglobin component (∼5%) in the blood of a healthy Costa Rican female, but not in her mother and two brothers (father not studied), that has an His→Arg replacement at position β77 (Hb Costa Rica). No other amino acid replacements were observed and no β- or γ-chain-like peptides were present. Hb Costa Rica has a normal stability. Sequence analyses of numerous polymerase chain reaction (PCR)-amplified segments of DNA that contain exon 2 of the β gene failed to identify a CAC→CGC (His→Arg) mutation. The same was the case when cDNA was sequenced, indicating that a β-Costa Rica-mRNA could not be detected with this procedure. Gene mapping of genomic DNA with BglII, BamHI, and HindIII gave normal fragments only and with the same intensity as observed for the fragments of a normal control. The quantities of the β chain variants Hb J-Iran and Hb Fukuyama with related mutations at β77 vary between 30% and 45% in heterozygotes, whereas that of Hb F-Kennestone with the same His→Arg mutation but in the ^Gγ-globin gene, is a high 40%–45% (as percentage of total ^Gγ) in a heterozygous newborn. These different observations exclude a heterozygosity of the A→G mutation at codon β77, as well as a deletion comparable to that of Hbs Lepore or Kenya, or a β-globin gene duplication, and point to a nontraditional inheritance of Hb Costa Rica. Allele-specific amplification of cDNA with appropriate primers identified the presence of a low level of mutated mRNA in the reticulocytes of the patient, which was confirmed by dotblot analysis of the same material with ³²P-labeled probes. Comparable amplification products were not observed in genomic DNA. The A→G mutation apparently occurred in a somatic cell at a relatively early stage in the development of the hematopoietic cell system, and Hb Costa Rica accumulated through rapid cell divisions in patchy areas in the bone marrow (somatic mosaicism). An unequal distribution of Hb Costa Rica over the red cells supports this possibility. Received: 25 August 1995 / Revised: 13 December 1995     

昆虫抗药性和昆虫毒理动力学(英文)

不断地使用一种杀虫药剂防治昆虫,会导致昆虫产生抗药性。对昆虫抗药性资料进行广泛综述时,发现了仅单独的解毒作用不能被解释为家蝇对有机氯杀虫药剂产生高抗性原因。作为一个基因。家蝇可以对有机氯产生比对有机磷杀虫剂更高的抗药性,尽管有机磷杀虫剂一般在虫体内是不太稳定的。考虑到昆虫毒理的动力学,杀虫药剂的穿透作用更显示出其实际的重要性。根据穿透和解毒的速率,慢的穿透作用是解毒作用的一个限制因子。防治敏感和抗性昆虫的观察结果,可以划出物理和生物因子之间关系的几种相关曲线图解。这些相关性不仅能说明家蝇对有机磷和有机氯杀虫剂的抗性程度,而且也助于选择出新的杀虫毒剂。