Relationship between shell structure and movement of Salmonella enteritidis across the eggshell wall.

1. Ultrastructural analyses of the eggshells of one strain of commercial layers indicated that the cuticular layer is rarely present as an even covering over the shell surface and the paired shell membranes are invariably pitted with holes larger than bacterial dimensions. 2. The above conditions pertain irrespective of the age of the laying bird. 3. Bacterial penetration of the eggshell is independent of pore numbers. 4. In the absence of a functional cuticle and with the shell membranes removed, bacteria are checked in their movement by structural modifications in the mammillary layer.     

Effect of feed intake and exogenous porcine somatotropin on longissimus muscle fiber characteristics of pigs weighing 55 kilograms live weight

Thirty two barrows were used in a 2 x 3 factorial arrangement to evaluate the effects of porcine somatotropin (pST) administration (USDA-pGH-B1; 0 and 100 micrograms.kg BW-1.d-1) and feed intake (FI; ad libitum [A], 1.64 [R1:80% of A] and 1.38 [R2:60% of A] kg/d) on longissimus (LM) muscle fiber characteristics of pigs growing from 25 to 55 kg live weight. The administration of pST resulted in an increase (P less than .05) in muscle fiber size (all three fiber types) and shear-force (17.1%). The percentage of muscle fiber types was not affected by pST treatment. Feeding of the diet at restricted levels (R1 and R2) resulted in smaller (P less than .05) beta R and alpha W fibers compared with feeding ad libitum. Pigs with ad libitum access to their diet had fewer alpha R fibers and more alpha W fibers in the LM compared with those fed at R1 and R2 levels. Restricted feed intake (R1 and R2) resulted in lower (P less than .05) shear-force values compared with ad libitum feeding. The present study indicates that pST administration of young barrows results in an increase in muscle hypertrophy. Restricted FI reduces both transformation from alpha R to alpha W fibers and muscle fiber hypertrophy.     

The effect of piperonyl butoxide and triorthocresyl phosphate on the activity and metabolism of altosid (isopropyl 11-methoxy, 3,7,11-trimethyldodeca-2,4-dienoate) in Tenebrio molitor L. and Oncopeltus fasciatus (dallas)

Altosid (I) was found to have an ED₅₀ of 0.026 μg/g in T. molitor and 5.0 μg/g in O. fasciatus. The juvenilizing activity of I in T. molitor was increased by co-treatment with piperonyl butoxide (PB) and triorthocresyl phosphate (TOCP). The activity of I in O. fasciatus, was considerably decreased by PB and TOCP indicating the blocking of an activation reaction. The presumptive metabolities of I, isopropyl 11-hydroxy-3,7,11-trimethyldodeca-2,4-dienoate, (II), 11-methoxy-3,7,11-trimethyldodeca-2,4-dienoic acid (III), and 11-hydroxy-3,7,11-trimethyldodeca-2,4-dienoic acid (IV) were tested for juvenilizing activity in O. fasciatus and II was found to be four times more active than I. IV was more active than III but less active than I. Co-treatment of II with PB or TOCP did not decrease activity, indicating that II is a true activation product. Uptake studies with ¹⁴C-I showed that the difference in activity between the two insects was not due to differences in uptake. Forty-eight hours after treatment 30% of I was lost from the cuticle by evaporation. Metabolic studies showed that PB inhibited the formation of II and TOCP inhibited the formation of III in T. molitor while in O. fasciatus both synergists inhibited the formation of II.     

Fenoxycarb,a selective insecticide for inclusion in integrated pest management systems for pear in the UK

The effects of fenoxycarb, an insect growth regulator, on predatory anthocorids, were tested in comparison with the broad-spectrum insecticide deltamethrin, in pear orchard trials. The results confirmed the effectiveness of fenoxycarb against pear sucker, Cacop- sylla pyricola and revealed no damaging effects on larval or adult anthocorids (mainly Anthocoris nemoralis). Deltamethrin reduced numbers of both C. pyricola and anthocorids, allowing a resurgence of C. pyricola later in the season. Fenoxycarb is shown to be suitable for use in integrated pest management programmes in pear.     

Genetic Fingerprinting of Potato Varieties from the Northwest Potato Variety Development Program

The Northwest Potato Variety Development (NWPVD) Program has released 45 improved potato varieties since 1985. Thirty-four potato varieties, four breeding clones and two advanced selections from NWPVD Program, and six commonly-grown potato varieties were fingerprinted using 32 simple sequence repeat (SSR) markers and 12,808 single nucleotide polymorphism (SNP) markers. Of 32 SSR markers, 29 exhibited significant polymorphism across all the 46 potato clones studied. A total of 143 alleles were observed with an average of 4.6 alleles per SSR marker. These markers span all 12 chromosomes of potato, with a maximum of five markers from chromosome VIII and minimum of one marker from chromosome VI. The polymorphic information content (PIC) and expected heterozygosity (H_e) of the SSR markers ranges between 0.18 to 0.75 and 0.20 to 0.78, respectively. Based on PIC, H_e, and ease of scoring, we recommend a set of eight SSR markers: STG0016, STI0004, STI0012, STI0023, STI0030, STI0033, STM1016 and STM1104 for fingerprinting NWPVD varieties. Out of 12,808 SNPs, 88.8% resulted in reliable three cluster diploid calling of which 87.8% were polymorphic. Tetraploid calling resulted in 44.2% of SNPs of which 94.5% were polymorphic. Our study provided fingerprinting resources for the NWPVD varieties and can be used in issues related to intellectual property rights, ownership, trademark and diversity analysis.     

Ecogeographical distribution of wild, weedy and cultivated Sorghum bicolor (L.) Moench in Kenya: implications for conservation and crop-to-wild gene flow

The potential gene flow between a crop and its wild relatives is largely determined by the overlaps in their ecological and geographical distributions. Ecogeographical databases are therefore indispensable tools for the sustainable management of genetic resources. In order to expand our knowledge of Sorghum bicolor distribution in Kenya, we conducted in situ collections of wild, weedy and cultivated sorghum. Qualitative and quantitative morphological traits were measured for each sampled wild sorghum plant. Farmers’ knowledge relating to the management of sorghum varieties and autecology of wild sorghum was also obtained. Cluster analysis supports the existence of several wild sorghum morphotypes that might correspond to at least three of the five ecotypes recognized in Africa. Intermediate forms between wild and cultivated sorghum belonging to the S. bicolor ssp. drummondii are frequently found in predominantly sorghum growing areas. Crop-wild gene flow in sorghum is likely to occur in many agroecosystems of Kenya.