Alternate current biosusceptometry for the assessment of gastric motility after proximal gastrectomy in rats: a feasibility study.

BACKGROUND: This study proposes an experimental model to assess the consequences of gastric surgeries on gastric motility. We investigated the effects of proximal gastrectomy (PG) using a non-invasive technique (alternate current biosusceptometry [ACB]) on gastric contractility (GC), gastric emptying (GE), and orocecal transit (OCT) after the ingestion of liquids and solids in rats. METHODS: Twenty-four male rats were subjected to gastric motility assessment before and after the PG procedure. The GE and OCT results are expressed as the mean time of gastric emptying (MGET) and cecum arrival (MCAT). The GC recordings are presented as the frequency and amplitude of contractions. KEY RESULTS: Mean time of gastric emptying after solid meals were significantly different (p < 0.001) between control and PG (113 ± 5 to 99 ± 6 min). Mean time of cecum arrival ranged from 265 ± 9 to 223 ± 11 min (p < 0.001) and 164 ± 9 to 136 ± 17 min (p < 0.050) for solid and liquid meals, respectively. The assessment of GC showed that surgery decreased the phasic frequency (4.4 ± 0.4 to 3.0 ± 1.1 cpm, p < 0.050) and increased the amplitude of contractions (3.6 ± 2.7 to 7.2 ± 3.0 V/s, p < 0.050). No significant difference was found in tonic frequency. CONCLUSIONS & INFERENCES: The ACB system was able to assess GE, OCT, and GC in gastrectomized rats. Overall, PG accelerated GE and gastrointestinal transit, likely due to the increase in both intragastric pressure and amplitude contraction. Our data presented an efficient model to investigate functional consequences from gastric surgeries that will allow further studies involving different procedures.

RAPD identification of Varroa destructor genotypes in Brazil and other regions of the Americas.

The mite Varroa destructor is the main pest causing damage to apiculture worldwide. In Brazil and other parts of the world, where bees of African origin and their hybrids predominate, the bees can survive these mites without treatment. Studies have shown a correlation between the various genotypes of the mite and its fertility in different geographical regions. Information about mite genotype could be helpful in understanding the diverse effects and relationships of the mite with bees in different regions of the world. DNA analysis by RAPD technique has permitted identification of three distinct genotypes in the mite V. destructor, namely Russian, Japanese and Papua New Guinea. We found predominance of the Russian genotype in Brazil, along with other parts of South America, and in Cuba and Mexico. The Japanese genotype was exclusively found on Fernando de Noronha Island in Brazil.

Genetic characterization of the mite Varroa destructor (Acari: Varroidae) collected from honey bees Apis mellifera (Hymenoptera, Apidae) in the state of Santa Catarina, Brazil.

The mite Varroa destructor is an ectoparasite that is considered a major pest for beekeeping with European honey bees. However, Africanized bee colonies are less threatened by this ectoparasite, because infestation levels remain low in these bees. The low reproductive ability of female mites of the Japanese biotype (J), introduced to Brazil early in the 1970s was initially considered the main factor for the lack of virulence of this parasite on Africanized bees. In other regions of the world where the Korean (K) biotype of this mite was introduced, there have been serious problems with Varroa due to the high reproductive potential of the mite. However, a significant increase in the reproductive rate of females of Varroa in Brazil has been recently demonstrated; the cause could be a change in the type of Varroa in the bee colonies. We evaluated the prevalence of haplotypes J and K in mite samples collected from the State of Santa Catarina and from the island of Fernando de Noronha in the State of Pernambuco. The analysis of the mitochondrial genome (PCR + RFLP) revealed haplotype K in all samples from Santa Catarina and haplotype J in all samples from Fernando de Noronha. The analysis of microsatellites (nuclear genome) in bees from Fernando de Noronha showed only the specific alleles of haplotype J, while in bees from Santa Catarina, these alleles were found in only 2.8% of the samples. The high frequency of individuals with Korean genetic material is probably to the reason for the current high reproductive capacity of the mite V. destructor recorded in Santa Catarina.

Prevalence of Salmonella in a poultry slaughterhouse.

The prevalence of Salmonella on surfaces, water, and broiler chicken (carcasses, parts, viscera, and spoils) taken from a poultry slaughterhouse located in the south of Brazil was studied. The automated mini-VIDAS system (a variation of the basic enzyme-linked immunosorbent assay) was used to screen for the presence of this microorganism in 615 samples, and the traditional culture method was used in 470 samples. We detected Salmonella in the following sampling points by the VIDAS Salmonella test: transport cages (16.7%), boxes (10%), scalding water (16.7%), chilled water (6.7%), carcass before evisceration (6.7%), carcass after chilling (3.3%), fresh breast (3.3%), fresh leg (10%), frozen wing (13.3%), frozen leg (13.3%), intestines (6.7%), skin of breast and leg (10%), and skin of neck (6.7%). Nevertheless, with the traditional culture method we only detected salmonellae in the following sampling points: scalding water (10%), fresh leg (6.7%), frozen wing (10%), skin of breast and leg (20%), and skin of neck (10%). Finally, 5.4% (33 of 615) of the samples analyzed by the VIDAS Salmonella system were positive, whereas the positive percentage with the traditional method was 2.6% (12 of 470). The results showed that transport cages, scalding water, frozen wing, frozen leg, and skin of breast and leg were the sampling points that demonstrated the greatest prevalence.

Mitochondrial genome differences between the stingless bees Melipona rufiventris and Melipona mondury (Apidae: Meliponini).

Within the Meliponini, a widely distributed group of stingless bees, Melipona rufiventris has been considered as a single, cohesive species. Recently, analysis of morphological characters led to the splitting of this species into two species, M. mondury and M. rufiventris. The former occurs in the Atlantic Rain Forest ranging from Santa Catarina to Bahia States, while the latter is found in other parts of Brazil. We used PCR + RFLP to identify genetic marker patterns of the mtDNA between these species. Nine mtDNA regions were amplified and digested with four restriction enzymes (EcoRI, EcoRV, HindIII, and HinfI). Six species-specific restriction sites were identified for M. mondury and M. rufiventris with all enzymes, except for HindIII. The molecular data agree with the morphological classification.

Mitochondrial genome differences between the stingless bees Melipona rufiventris and Melipona mondury (Apidae: Meliponini)

Within the Meliponini, a widely distributed group of stingless bees, Melipona rufiventris has been considered as a single, cohesive species. Recently, analysis of morphological characters led to the splitting of this species into two species, M. mondury and M. rufiventris. The former occurs in the Atlantic Rain Forest ranging from Santa Catarina to Bahia States, while the latter is found in other parts of Brazil. We used PCR + RFLP to identify genetic marker patterns of the mtDNA between these species. Nine mtDNA regions were amplified and digested with four restriction enzymes (EcoRI, EcoRV, HindIII, and HinfI). Six species-specific restriction sites were identified for M. mondury and M. rufiventris with all enzymes, except for HindIII. The molecular data agree with the morphological classification.

Maternal influence on the acceptance of virgin queens introduced into Africanized honey bee (Apis mellifera) colonies.

The oviposition potential of honey bee queens decreases with age, therefore it is important to replace old queens with younger ones on a periodic basis. However, queen replacement is problematic, especially in Africanized honey bee colonies, since many introduced queens are not accepted, and virgin queens are less easily accepted than are mated queens. We assessed the influence of genetic origin (queen mother) on the acceptance of queens, when they were introduced as virgins into Africanized honey bee colonies. For this purpose, 12 daughter queens from each of 11 mother queens with no degree of kinship among themselves were introduced. Introductions were made monthly, for 12 months, though the winter months of June and July were not included, as there is little brood and drones are rare in winter. There was some seasonal variation in the acceptance rates; generally there was greater acceptance in months with good honey flows. However, the acceptance of introduced queens was influenced by their origin. The rate of acceptance of daughter queens from the 11 different mother queens varied significantly, ranging from 33 to 75%. There appears to be a genetic influence of the mother queen on the introduced queen acceptance rate.

Maternal influence on the acceptance of virgin queens introduced into Africanized honey bee (Apis mellifera) colonies

The oviposition potential of honey bee queens decreases with age, therefore it is important to replace old queens with younger ones on a periodic basis. However, queen replacement is problematic, especially in Africanized honey bee colonies, since many introduced queens are not accepted, and virgin queens are less easily accepted than are mated queens. We assessed the influence of genetic origin (queen mother) on the acceptance of queens, when they were introduced as virgins into Africanized honey bee colonies. For this purpose, 12 daughter queens from each of 11 mother queens with no degree of kinship among themselves were introduced. Introductions were made monthly, for 12 months, though the winter months of June and July were not included, as there is little brood and drones are rare in winter. There was some seasonal variation in the acceptance rates; generally there was greater acceptance in months with good honey flows. However, the acceptance of introduced queens was influenced by their origin. The rate of acceptance of daughter queens from the 11 different mother queens varied significantly, ranging from 33 to 75%. There appears to be a genetic influence of the mother queen on the introduced queen acceptance rate.

Infestation and distribution of the mite Varroa destructor in colonies of Africanized bees.

Whereas in several parts of the world varroa is the major pest affecting apiculture, in others the parasite is unknown to many beekeepers because its damage to bees is minor. The impact of the mite Varroa destructor is related to the climatic conditions and the races of Apis mellifera bees in each region where the pest exists. In the present study, the current level of infestation by the mite was assessed to determine the evolution of the pest in Africanized bee colonies in Southern Brazil. This level of infestation was considered low: approximately two mites per one hundred adult bees. This result is similar to that obtained for the same apiary almost five years ago and for others distributed in various regions of Brazil. In the present study, we also estimated the total varroa population and its distribution among brood and adults in each bee colony.

Infestation and distribution of the mite Varroa destructor in colonies of africanized bees

Whereas in several parts of the world varroa is the major pest affecting apiculture, in others the parasite is unknown to many beekeepers because its damage to bees is minor. The impact of the mite Varroa destructor is related to the climatic conditions and the races of Apis mellifera bees in each region where the pest exists. In the present study, the current level of infestation by the mite was assessed to determine the evolution of the pest in Africanized bee colonies in Southern Brazil. This level of infestation was considered low: approximately two mites per one hundred adult bees. This result is similar to that obtained for the same apiary almost five years ago and for others distributed in various regions of Brazil. In the present study, we also estimated the total varroa population and its distribution among brood and adults in each bee colony

Infestation and distribution of the mite Varroa destructor in colonies of africanized bees

Whereas in several parts of the world varroa is the major pest affecting apiculture, in others the parasite is unknown to many beekeepers because its damage to bees is minor. The impact of the mite Varroa destructor is related to the climatic conditions and the races of Apis mellifera bees in each region where the pest exists. In the present study, the current level of infestation by the mite was assessed to determine the evolution of the pest in Africanized bee colonies in Southern Brazil. This level of infestation was considered low: approximately two mites per one hundred adult bees. This result is similar to that obtained for the same apiary almost five years ago and for others distributed in various regions of Brazil. In the present study, we also estimated the total varroa population and its distribution among brood and adults in each bee colony.

Enquanto em diversas partes do mundo a varroa é considerada a mais preocupante peste que afeta a apicultura, em outras o parasita é desconhecido de muitos apicultores em razão dos poucos danos causados às abelhas. O impacto do ácaro Varroa destructor está relacionado às condições climáticas e à raça de abelhas Apis mellifera em cada região onde a praga se estabeleceu. No presente estudo foram avaliadas a evolução da varroatose e a distribuição do ácaro Varroa destructor em colônias de abelhas africanizadas no sul do Brasil. O grau de infestação alcançado pela praga varroatose nas colônias de abelhas envolvidas neste trabalho foi de aproximadamente dois ácaros para cada cem abelhas. Esta infestação é semelhante à encontrada no mesmo apiário e em outros de várias regiões do Brasil aproximadamente cinco anos atrás. Neste estudo também foram avaliadas a população total de varroas e a sua distribuição entre as crias e as abelhas adultas.